Catalytic Fast Pyrolysis of Cellulose Using Nano Zeolite and Zeolite/Matrix Catalysts in a GC/Micro-Pyrolyzer.

PubMed

Lee, Kyong-Hwan

2016-05-01

Cellulose, as a model compound of biomass, was catalyzed over zeolite (HY,.HZSM-5) and zeolite/matrix (HY/Clay, HM/Clay) in a GC/micro-pyrolyzer at 500 degrees C, to produce the valuable products. The catalysts used were pure zeolite and zeolite/matrix including 20 wt% matrix content, which were prepared into different particle sizes (average size; 0.1 mm, 1.6 mm) to study the effect of the particle size of the catalyst for the distribution of product yields. Catalytic pyrolysis had much more volatile products as light components and less content of sugars than pyrolysis only. This phenomenon was strongly influenced by the particle size of the catalyst in catalytic fast pyrolysis. Also, in zeolite and zeolite/matrix catalysts the zeolite type gave the dominant impact on the distribution of product yields.

A Miniature Mineralogical Instrument for In-Situ Characterization of Ices and Hydrous Minerals at the Lunar Poles

NASA Technical Reports Server (NTRS)

Sarrazin, P.; Blake, D.; Vaniman, D.; Bish, D.; Chipera, S.; Collins, S. A.

2002-01-01

Lunar missions over the past few years have provided new evidence that water may be present at the lunar poles in the form of cold-trapped ice deposits, thereby rekindling interest in sampling the polar regions. Robotic landers fitted with mineralogical instrumentation for in-situ analyses could provide unequivocal answers on the presence of crystalline water ice and/or hydrous minerals at the lunar poles. Data from Lunar Prospector suggest that any surface exploration of the lunar poles should include the capability to drill to depths of more than 40 cm. Limited data on the lunar geotherm indicate temperatures of approximately 245-255 K at regolith depths of 40 cm, within a range where water may exist in the liquid state as brine. A relevant terrestrial analog occurs in Antarctica, where the zeolite mineral chabazite has been found at the boundary between ice-free and ice-cemented regolith horizons, and precipitation from a regolith brine is indicated. Soluble halogens and sulfur in the lunar regolith could provide comparable brine chemistry in an analogous setting. Regolith samples collected by a drilling device could be readily analyzed by CheMin, a mineralogical instrument that combines X-ray diffraction (XRD) and X-ray fluorescence (XRF) techniques to simultaneously characterize the chemical and mineralogical compositions of granular or powdered samples. CheMin can unambiguously determine not only the presence of hydrous alteration phases such as clays or zeolites, but it can also identify the structural variants or types of clay or zeolite present (e.g., well-ordered versus poorly ordered smectite; chabazite versus phillipsite). In addition, CheMin can readily measure the abundances of key elements that may occur in lunar minerals (Na, Mg, Al, Si, K, Ca, Fe) as well as the likely constituents of lunar brines (F, Cl, S). Finally, if coring and analysis are done during the lunar night or in permanent shadow, CheMin can provide information on the chemistry and structure of any crystalline ices that might occur in the regolith samples.

Bentonite Clay Evolution at Elevated Pressures and Temperatures: An experimental study for generic nuclear repositories

NASA Astrophysics Data System (ADS)

Caporuscio, F. A.; Cheshire, M.; McCarney, M.

2012-12-01

The Used Fuel Disposition Campaign is presently engaged in looking at various generic repository options for disposal of used fuel. Of interest are the disposal of high heat load canisters ,which may allow for a reduced repository footprint. The focus of this experimental work is to characterize Engineered Barrier Systems (EBS) conditions in repositories. Clay minerals - as backfill or buffer materials - are critical to the performance of the EBS. Experiments were performed in Dickson cells at 150 bar and sequentially stepped from 125 oC to 300 oC over a period of ~1 month. An unprocessed bentonite from Colony, Wyoming was used as the buffer material in each experiment. An K-Ca-Na-Cl-rich brine (replicating deep Stripa groundwater) was used at a 9:1 water:rock ratio. The baseline experiment contained brine + clay, while three other experiments contained metals that could be used as waste form canisters (brine +clay+304SS, brine+clay+316SS, brine+clay+Cu). All experiments were buffered at the Mt-Fe oxygen fugacity univarient line. As experiment temperature increased and time progressed, pH, K and Ca ion concentrations dropped, while Si, Na, and SO4 concentrations increased. Silicon was liberated into the fluid phase (>1000 ppm) and precipitated during the quenching of the experiment. The precipitated silica transformed to cristobalite as cooling progressed. Potassium was mobilized and exchanged with interlayer Na, transitioning the clay from Na-montmorillonite to K-smectite. Though illitization was not observed in these experiments, its formation may be kinetically limited and longer-term experiments are underway to evaluate the equilibrium point in this reaction. Clinoptilolite present in the starting bentonite mixture is unstable above 150 oC. Hence, the zeolite broke down at high temperatures but recrystallized as the quench event occurred. This was borne out in SEM images that showed clinoptilolite as a very late stage growth mineral. Both experimental runs containing steel exhibit the generation of a chlorite / Fe-saponite layer at the clay-metal boundary. The formation of minor amounts of pentlandite [(Fe,Ni)9S8] also occurs on both steel plates. Chalcocite (Cu2S) formed as a corrosion product on the Cu plates. The two sulfide phases have been produced by the generation of H2S gas during the experimental runs. The H2S is formed by the breakdown of pyrite framboids at high temperature in the bentonite. Such experiments on representative EBS materials at elevated P,T repository conditions are providing useful information for generic repository studies. Lack of illite formation is common in clay experiments and may be related to kinetics or K concentration. Precipitated SiO2 may potentially seal heating cracks in the clay backfill. The chlorite layer generated on steel may act as a passivation material and prevent corrosion of the steel canister wall. Finally, even if zeolites break down during the high temperature thermal pulse of a repository, zeolites may form again as the repository inventory cools off and perform as radionuclide sorbing phases.

Subglacial hydrothermal alteration minerals in Jökulhlaup deposits of Southern Iceland, with implications for detecting past or present habitable environments on Mars.

PubMed

Warner, Nicholas H; Farmer, Jack D

2010-06-01

Jökulhlaups are terrestrial catastrophic outfloods, often triggered by subglacial volcanic eruptions. Similar volcano-ice interactions were likely important on Mars where magma/lava may have interacted with the planet's cryosphere to produce catastrophic floods. As a potential analogue to sediments deposited during martian floods, the Holocene sandurs of Iceland are dominated by basaltic clasts derived from the subglacial environment and deposited during jökulhlaups. Palagonite tuffs and breccias, present within the deposits, represent the primary alteration lithology. The surface abundance of palagonite on the sandurs is 1-20%. X-ray diffraction (XRD) analysis of palagonite breccias confirms a mineral assemblage of zeolites, smectites, low-quartz, and kaolinite. Oriented powder X-ray diffractograms (< 2 microm fraction) for palagonite breccia clasts and coatings reveal randomly ordered smectite, mixed layer smectite/illite, zeolites, and quartz. Visible light-near infrared (VNIR) and shortwave infrared (SWIR) lab spectroscopic data of the same palagonite samples show H2O/OH(-) absorptions associated with clays and zeolites. SWIR spectra derived from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) images of the sandurs reveal Al-OH(-) and Si-OH(-) absorption features. The identified alteration mineral assemblage is consistent with low temperature (100-140 degrees C) hydrothermal alteration of basaltic material within the subglacial environment. These results suggest that potential martian analog sites that contain a similar suite of hydrated minerals may be indicative of past hydrothermal activity and locations where past habitable environments for microbial life may be found.

Effect of clay minerals and nanoparticles on chromium fractionation in soil contaminated with leather factory waste.

PubMed

Taghipour, Marzieh; Jalali, Mohsen

2015-10-30

This study was conducted to investigate the effect of time, clay minerals and nanoparticles (NPs) on chromium (Cr) fractionation in a soil contaminated with leather factory waste (LFW). Soil was mixed with LFW, then, the contaminated soils were treated with clay minerals (bentonite and zeolite) and nanoparticles (MgO, TiO2 and ZnO) at 5% and 1%, respectively. The samples were incubated for 15-180 days at 25 °C and constant moisture. After incubation, Cr in control and treated soils was fractionated by the sequential extraction procedure. The distribution of various Cr fractions in control soil indicated that the greatest amounts of Cr were found in the residual fraction (RES) followed by the carbonate (CAR), organic matter (OM) and exchangeable (EXC) fractions. The addition of LFW in soils increased Cr concentration in all fractions. The higher proportion of EXC fraction in the soil treated with LFW indicates its higher potential of leaching and runoff transport. In all treated soils, the RES fraction was increased, while EXC and OM fractions were decreased during incubation. The results indicated that NPs are effective adsorbent for the removal of Cr ions from LFW treated soil, and they could be useful in reducing their environment risk. Copyright © 2015 Elsevier B.V. All rights reserved.

Natural and synthetic mineral silicates as functional nanoparticles in polymer composites

NASA Astrophysics Data System (ADS)

Shao, Hua

A new strategy is described for the substantial enhancement of the barrier properties for both a thermoset epoxy polymer and a thermoplastic polyolefin by sandwiching a novel self-supported clay fabric film between thin polymer sheets. The success of this strategy is attributed to the high orientation of clay nanolayers in the paper-like clay fabric films and to the filling of the micro- or sub-micro sized voids between imperfectly tiled clay platelet edges by the polymer chains. Thermoplastic polyolefin-clay fabric film composites were fabricated by hot-pressing the clay films between two sheets of high density polyethylene (HDPE) films. The sandwiched composites exhibit more than a 30-fold decrease in O2 transmission rate with respect to the pure HDPE film. Impregnating the self-supported clay papers with epoxy pre-polymers successfully leads to thermoset composite films with more than 2-3 orders of magnitude reduction in O2 permeability in comparison to the pristine epoxy matrix. Owing to the promising use of synthetic Mg-saponite (denoted SAP) as epoxy polymer reinforcing agents, we investigated the cost-effective synthesis of SAP by replacing urea with sodium hydroxide as base source. Co-crystallization of new zeolite phases, such as garronite (denoted GIS) and cancrinite (denoted CAN), occurred along with SAP upon increasing the alkalinity of the reaction mixture. This finding represents the first example of the preparation of a CAN/SAP phase mixture. Moreover, pure-phase cancrinite with rod-like morphology up to several mum in length was synthesized under Mg-free conditions. Also, the Si/AI ratio within the synthesis gel has an influence on the chemical composition and textural properties of pure CAN crystals. Microporous cancrinite is a promising candidate for reinforcing epoxy polymers, considering that CAN represents a substantial fraction of the mixed CAN-SAP phase formed during the synthesis of saponite. Therefore, the reaction conditions (e.g. alkalinity, reaction temperature, and duration) were further expored in order to optimize the formation of small crystals of CAN (˜ 100 nm) with large external surface area and high pore volume. These textural features facilitate the homogeneous dispersion of cancrinite particles in epoxy matrices. In addition, a new phase sodalite (denoted SOD) was co-crystallized along with CAN in some cases, depending on reaction conditions. The synthetic zeolites CAN and SOD act as reinforcing agents for thermoset epoxy polymers owing in part to their small particle size, large surface area and high pore volume. The tensile strength, modulus and toughness of an epoxy matrix are simultaneously enhanced without the need for organic surface modification of zeolites. This finding represents the first example for which the mechanical properties of glassy epoxy composite are all improved through the use of a microporous zeolite as a functional inorganic nanoparticle.

Toluene, Methanol and Benzaldehyde Removal from Gas Streams by Adsorption onto Natural Clay and Faujasite-Y type Zeolite.

PubMed

Zaitan, Hicham; Mohamed, Elham F; Valdés, Héctor; Nawdali, Mostafa; Rafqah, Salah; Manero, Marie Hélène

2016-12-01

A great number of pollution problems come as a result of the emission of Volatile Organic Compounds (VOCs) into the environment and their control becomes a serious challenge for the global chemical industry. Adsorption is a widely used technique for the removal of VOCs due to its high efficiency, low cost, and convenient operation. In this study, the feasibility to use a locally available clay, as adsorbent material to control VOCs emissions is evaluated. Natural clay is characterised by different physical-chemical methods and adsorptive interaction features between VOCs and natural clay are identified. Toluene (T), methanol (M) and benzaldehyde (B) are used here as representatives of three different kinds of VOCs. Adsorption isotherms onto natural clay and faujasite-Y type zeolite (Fau Y) are obtained at room temperature. According to Langmuir model data, maximum adsorption capacities (qm) of Fez natural clay and zeolite toward methanol (M), toluene (T) and benzaldehyde (B) at 300 K are 8, 0.89 and 3.1 mmol g-1, and 15, 1.91 and 13.9 mmol g-1 respectively. In addition, the effect of temperature on the adsorption of toluene onto natural clay is evaluated in the range from 300 to 323K. An increase on temperature reduces the adsorption capacity of natural clay toward toluene, indicating that an exothermic physical adsorption process takes place. The enthalpy of adsorption of toluene onto Fez natural clay was found to be -54 kJ mol-1. A preliminary cost analysis shows that natural clay could be used as an alternative low cost adsorbent in the control of VOCs from contaminated gas streams with a cost of US$ 0.02 kg-1 compared to Fau Y zeolite with US$ 10 kg-1.

Mineralogical and geomicrobial examination of soil contamination by radioactive Cs due to 2011 Fukushima Daiichi Nuclear Power Plant accident

NASA Astrophysics Data System (ADS)

Akai, Junji; Nomura, Nao; Matsushita, Shin; Kudo, Hisaaki; Fukuhara, Haruo; Matsuoka, Shiro; Matsumoto, Jinko

Soil contamination by radioactive Cs from Fukushima Daiichi Nuclear Power Plant accident was investigated. Absorption and desorption experiments of Cs were conducted for several phyllosillicates (kaolinite, sericite, montmorillonite, vermiculite, chrysotile and biotite), zeolite and solid organic matter (dead and green leaves). The results confirmed the characteristic sorption and desorption of Cs by these materials. The 2:1 type phyllosilicate, especially, vermiculite and montmorillonite absorbed Cs well. Heated vermiculite for agricultural use and weathered montmorillonite also adsorbed Cs. Leaves also absorbed Cs considerably but easily desorbed it. In summary, the relative capacity and strength of different materials for sorption of Cs followed the order: zeolite (clinoptilolite) > 2:1 type clay mineral > 1:1 type clay mineral > dead and green leaves. Culture experiments using bacteria of both naturally living on dead leaves in Iitate village, Fukushima Pref. and bacterial strains of Bacillus subtillis, Rhodococus erythropolis, Streptomyces aomiensis and Actinomycetospora chlora were carried out. Non-radioactive 1% Cs solution (CsCl) was added to the culture media. Two types of strong or considerable bacterial uptakes of Cs were found in bacterial cells. One is that Cs was contained mainly as globules inside bacteria and the other is that Cs was absorbed in the whole bacterial cells. The globules consisted mainly of Cs and P. Based on all these results, future diffusion and re-circulation behavior of Cs in the surface environment was discussed.

The role of external and internal mass transfer in the process of Cu2+ removal by natural mineral sorbents.

PubMed

Sljivić, M; Smiciklas, I; Plećas, I; Pejanović, S

2011-07-01

The kinetics of Cu2+ sorption on to zeolite, clay and diatomite was investigated as a function of initial metal concentrations. For consideration of the mass transfer phenomena, single resistance models based on both film and intraparticle diffusion were tested and compared. The obtained results suggested that the rate-limiting step in Cu2+ sorption strongly depended on the sorbent type, as well as on initial cation concentration. The decrease in external mass transfer coefficients with the increase in initial metal concentrations was in excellent agreement with expressions based on Sherwood and Schmidt dimensionless numbers. The internal diffusivities through zeolite particles were in the range 1.0 x 10(-11) to 1.0 x 10(-13) m2/min, depending on the Cu2+ concentration and the applied theoretical model.

Removal of xenobiotics from effluent discharge by adsorption on zeolite and expanded clay: an alternative to activated carbon?

PubMed

Tahar, A; Choubert, J M; Miège, C; Esperanza, M; Le Menach, K; Budzinski, H; Wisniewski, C; Coquery, M

2014-04-01

Xenobiotics such as pesticides and pharmaceuticals are an increasingly large problem in aquatic environments. A fixed-bed adsorption filter, used as tertiary stage of sewage treatment, could be a solution to decrease xenobiotics concentrations in wastewater treatment plants (WWTPs) effluent. The adsorption efficiency of two mineral adsorbent materials (expanded clay (EC) and zeolite (ZE)), both seen as a possible alternative to activated carbon (AC), was evaluated in batch tests. Experiments involving secondary treated domestic wastewater spiked with a cocktail of ten xenobiotics (eight pharmaceuticals and two pesticides) known to be poorly eliminated in conventional biological process were carried out. Removal efficiencies and partitions coefficients were calculated for two levels of initial xenobiotic concentration, i.e, concentrations lower to 10 μg/L and concentrations ranged from 100 to 1,000 μg/L. While AC was the most efficient adsorbent material, both alternative adsorbent materials showed good adsorption efficiencies for all ten xenobiotics (from 50 to 100 % depending on the xenobiotic/adsorbent material pair). For all the targeted xenobiotics, at lower concentrations, EC presented the best adsorption potential with higher partition coefficients, confirming the results in terms of removal efficiencies. Nevertheless, Zeolite presents virtually the same adsorption potential for both high and low xenobiotics concentrations to be treated. According to this first batch investigation, ZE and EC could be used as alternative absorbent materials to AC in WWTP.

Zeolites in Eocene basaltic pillow lavas of the Siletz River Volcanics, Central Coast Range, Oregon

USGS Publications Warehouse

Keith, Terry E.C.; Staplese, Lloyd W.

1985-01-01

Zeolites and associated minerals occur in a tholeiitic basaltic pillow lava sequence that makes up part of the Eocene Siletz River Volcanics in the central Coast Range, Oregon. Regional zoning of zeolite assemblages is not apparent; the zeolites formed in joints, fractures, and interstices, although most occur in central cavities of basalt pillows. The zeolites and associated minerals identified, in general order of paragenetic sequence, are smectite, pyrite, calcite (small spheres), thomsonite, natrolite, analcime, scolecite, mesolite, stilbite, heulandite, apophyllite, chahazite, mordenite, calcite (scalenohedra and twinned rhombohedra), laumontite, and amethystine quartz. Common three-mineral assemblages are: natrolite-analcime-sfilbite, stilbite-heulandite-chabazite, stilbite-apophyllie-chabazite, and natrolite-mesolite-laumontite.Alteration of basaltic glass, which was initially abundant, appears to have been an important factor in formation of the zeolites. Isotopic data suggest that zeolitization occurred during a low-temperature (60 ~ 70°C submarine hydrothermal event, or by reactions of cold (~ 10°C meteoric water with basalt over a long time. The occurrence of different mineral assemblages in cavities of adjacent basalt pillows indicates that these minerals crystallized in dosed systems that were isolated as fractures and joints were sealed by deposition of smectite and early zeolites. Although the total chemical composition of the mineral assemblages in cavities is similar, different mineral species formed because of the sensitivity of zeolite minerals to slight variations in physical and chemical conditions within individual cavities.

Synthesis and Properties of Nanoparticle Forms Saponite Clay, Cancrinite Zeolite and Phase Mixtures Thereof.

PubMed

Shao, Hua; Pinnavaia, Thomas J

2010-09-01

The low-temperature synthesis (90°C) of nanoparticle forms of a pure phase smectic clay (saponite) and zeolite (cancrinite) is reported, along with phase mixtures thereof. A synthesis gel corresponding to the Si:Al:Mg unit cell composition of saponite (3.6:0.40:3.0) and a NaOH/Si ratio of 1.39 affords the pure phase clay with disordered nanolayer stacking. Progressive increases in the NaOH/Si ratio up to a value of 8.33 results in the co-crystallization of first garronite and then cancrinite zeolites with nanolath morphology. The resulting phase mixtures exhibit a compound particulate structure of intertwined saponite nanolayers and cancrinite nanolaths that cannot be formed through physical mixing of the pure phase end members. Under magnesium-free conditions, pure phase cancrinite nanocrystals are formed. The Si/Al ratio of the reaction mixture affects the particle morphology as well as the chemical composition of the cancrinite zeolite. Ordinarily, cancrinite crystallizes with a Si/Al ratio of 1.0, but a silicon-rich form of the zeolite (Si/Al=1.25) is crystallized at low temperature from a silica rich synthesis gel, as evidenced by (29)Si NMR spectroscopy and XEDS-TEM. Owing to the exceptionally high external surface areas of the pure phase clay (875 m(2)/g) and zeolite end members (8.9 - 40 m(2)/g), as well as their unique mixed phase composites (124 - 329 m(2)/g), these synthetic derivatives are promising model nanoparticles for studies of the bioavailability of poly-aromatic hydrocarbons immobilized in silicate bearing sediments and soils.

Preliminary evaluation of the landsat-4 thematic mapper data for mineral exploration

USGS Publications Warehouse

Podwysocki, M.H.; Power, M.S.; Jones, O.D.

1985-01-01

Landsat-4 Thematic Mapper (TM) data recorded over an arid terrain were analyzed to determine the applicability of using of TM data for identifying and mapping hydrothermally altered, potentially mineralized rocks. Clays, micas, and other minerals bearing the OH anion in specific crystal lattice positions have absorption bands in the 2.2-??m region (TM channel 7, TM7) and commonly lack features in the 1.6-??m region (TM5). Channel ratios TM5/TM7, TM5/TM4, and TM3/TM1 were combined into a color-ratio-composite (CRC) image and used to distinguish hydrothermally altered rocks, unaltered rocks, and vegetation. These distinctions are made possible by using the TM5 and TM7, channels which are not available in the Landsat multispectral scanner (MSS). Digital masking was used to eliminate ambiguities due to water and shadows. However, some ambiguities in identification resulted between altered volcanic rocks and unaltered sedimentary deposits that contained clays, carbonates, and gypsum, and between altered volcanic rocks and volcanic tuffs diagenetically altered to zeolites. However, compared to MSS data, TM data should greatly improve the ability to map hydrothermally altered rocks in arid terrains. ?? 1985.

Spectroscopic investigations of humic-like acids formed via polycondensation reactions between glycine, catechol and glucose in the presence of natural zeolites

NASA Astrophysics Data System (ADS)

Fukuchi, Shigeki; Miura, Akitaka; Okabe, Ryo; Fukushima, Masami; Sasaki, Masahide; Sato, Tsutomu

2010-10-01

Polycondensation reactions between low-molecular-weight compounds, such as amino acids, sugars and phenols, are crucially important processes in the formation of humic substances, and clay minerals have the ability to catalyze these reactions. In the present study, catechol (CT), glycine (Gly) and glucose (Gl) were used as representative phenols, amino acids and sugars, respectively, and the effects of the catalytic activities of natural zeolites on polycondensation reactions between these compounds were investigated. The extent of polycondensation was evaluated by measuring the specific absorbance at 600 nm ( E600) as an index of the degree of darkening. After a 3-week incubation period, the E600 values for solutions that contained zeolite samples were 4-10 times greater than those measured in the absence of zeolite, suggesting that the zeolite had, in fact, catalyzed the polycondensation reaction. The humic-like acids (HLAs) produced in the reactions were isolated, and their elemental composition and molecular weights determined. When formed in the presence of a zeolite, the nitrogen contents and molecular weights for the HLAs were significantly higher, compared to the HLA sample formed in the absence of zeolite. In addition, solid-state CP-MAS 13C NMR spectra and carboxylic group analyses of the HLA samples indicated that the concentration of carbonyl carbon species for quinones and ketones produced in the presence of zeolite were higher than the corresponding values for samples produced in the absence of a zeolite. Carbonyl carbons in quinones and ketones indicate the nucleophilic characteristics of the samples. Therefore, a nitrogen atom in Gly, which serves as nucleophile, is incorporated into quinones and ketones in CT and Gl. The differences in the catalytic activities of the zeolite samples can be attributed to differences in their transition metal content (Fe, Mn and Ti), which function as Lewis acids.

Stable isotope and mineralogical investigation of the genesis of amethyst geodes in the Los Catalanes gemological district, Uruguay, southernmost Paraná volcanic province

NASA Astrophysics Data System (ADS)

Duarte, Lauren C.; Hartmann, Leo A.; Ronchi, Luiz H.; Berner, Zsolt; Theye, Thomas; Massonne, Hans J.

2011-03-01

Stable isotopes (C, O, S) and mineralogical studies of the world-class amethyst-geode deposits of the Los Catalanes gemological district, Uruguay, constrain processes operative during mineral deposition. The mineralized basaltic andesites from the Cretaceous Paraná volcanic province are intensely altered to zeolites (clinoptilolite) and clay minerals. Variations in the δ18O values of silica minerals in geodes (chalcedony, quartz, and amethyst) are much larger and the values generally somewhat lower (21.2-31.5‰) in the Uruguayan deposits than in the Ametista do Sul area of southern Brazil. The range of δ34S values (-15.0 to -0.3‰) of altered basaltic rocks requires (in addition to sulfur of magmatic origin) the involvement of 34S-depleted sedimentary sulfur from bacterial sulfate reduction. The results delimit the mineralizing processes to a post-eruption environment characterized by low temperature and strong interaction of the lava flows with meteoric water.

X-Ray Fingerprinting Techniques for Recognizing A Hydrological Role in the Formation of Minerals on the Surface of Mars

NASA Technical Reports Server (NTRS)

Metzger, Ellen P.; John, R.

1999-01-01

Previous work has demonstrated the ability of a miniaturized XRD-XRF instrument to perform in-situ analyses without sample preparation or acquisition. Deployment of this instrument on a Martian rover will allow a large number of rapid qualitative analyses, which will maximize the diversity of samples studied and selected for possible return. As a first step in designing a decision tree for recognizing minerals in complex mixtures, d spacings were plotted against intensity for several mineral groups comprising rock and soil types inferred for the surface of Mars (weathered basalt, playa and hydrothermal deposits, clay-rich soils). In all groups, d spacings cluster in a range from about 1-4 angstroms, which can under certain circumstances obscure patterns for individual phases. However, within the silicate family, minerals containing either bound OH- or molecules of H20 (clays, micas, amphiboles, zeolites) are characterized by a shift of peaks to higher d spacings. Large d spacings (greater than about 7 angstroms) thus act as a first-order filter for distinguishing hydrous from anhydrous silicates. The ability to quickly verify the presence of silicates that have interacted with water has important implications for using mineral chemistry and structure to help decipher the hydrologic and atmospheric history of Mars. This represents a beginning for developing more sophisticated methods of pattern recognition. These will combine XRD and XRF analyses with optical data to rapidly7 discern environmentally diagnostic assemblages without the necessity of identifying every peak individual mineral phase.

Soda Creek springs - metamorphic waters in the eastern Alaska Range

USGS Publications Warehouse

Richter, D.H.; Donaldson, D.E.; Lamarre, R.A.

1973-01-01

The Soda Creek springs are a group of small, cold mineral springs on the southern flank of the eastern Alaska Range. The spring waters contain anomalous concentrations of carbon dioxide, sodium, chlorine, sulfate, boron, and ammonia and are actively precipitating deposits of calcite and aragonite. Sparingly present in these deposits are mixed-layer illite-montmorillonite clays and zeolite minerals. Low-temperaturemetamorphic reactions in subjacent marine sedimentary rocks of Jurassic and Cretaceous age may have produced the fluids and silicate minerals. With only a few exceptions, cool bicarbonate-rich springs in Alaska are concentrated south of the Denali fault system in south-central Alaska, southeastern Alaska, and along the Kaltag-Tintina fault system. These areas are characterized by active or recently activetectonism, major faults and folds, and an abundance of marine sedimentary rocks.

Zirconium-modified materials for selective adsorption and removal of aqueous arsenic

DOEpatents

Zhao, Hongting; Moore, Robert C.

2004-11-30

A method, composition, and apparatus for removing contaminant species from an aqueous medium comprising: providing a material to which zirconium has been added, the material selected from one or more of zeolites, cation-exchangeable clay minerals, fly ash, mesostructured materials, activated carbons, cellulose acetate, and like porous and/or fibrous materials; and contacting the aqueous medium with the material to which zirconium has been added. The invention operates on all arsenic species in the form of arsenate, arsenite and organometallic arsenic, with no pretreatment necessary (e.g., oxidative conversion of arsenite to arsenate).

Recommended nomenclature for zeolite minerals: report of the subcommittee on zeolites of the International Mineralogical Association, Commission of New Minerals and Mineral Names

USGS Publications Warehouse

Coombs, D.S.; Alberti, A.; Armbruster, T.; Artioli, G.; Colella, C.; Galli, E.; Grice, Joel D.; Liebau, F.; Mandarino, J.A.; Minato, H.; Nickel, E.H.; Passaglia, E.; Peacor, D.R.; Quartieri, S.; Rinaldi, R.; Ross, M.; Sheppard, R.A.; Tillmanns, E.; Vezzalini, G.

1998-01-01

This report embodies recommendations on zeolite nomenclature approved by the International Mineralogical Association Commission of New Minerals and Mineral Names. In a working definition of a zeolite mineral used for review, interrupted tetrahedral framework structures are accepted where other zeolitic properties prevail, and complete substitution by elements other than Si and Al is allowed. Separate species are recognized in topologically distinctive compositional series in which different extra-framework cations are the most abundance in atomic proportions. To name these, the appropriate chemical symbol is attached by a hyphen to the series name as a suffix except for the names harmotome, pollucite and wairakite in the phillipsite and analcime series. Differences in space-group symmetry and in order-disorder relationships in zeolites having the same topologically distinctive framework do not in general provide adequate grounds for recognition of separate species. Zeolite species are not to be distinguished solely on Si:Al ratio except for heulandite (Si:Al < 4.0) and clinoptilolite (Si:Al ??? 4.0). Dehydration, partial hydration, and over-hydration are not sufficient grounds for the recognition of separate species of zeolites. Use of the term 'ideal formula' should be avoided in referring to a simplified or averaged formula of a zeolite. Newly recognized species in compositional series are as follows: brewsterite-Sr.-Ba: chabazite-Ca.-Na.-K; clinoptilolite-K, -Na, -Ca: dachiardite-Ca, -Na; erionite-K, -Ca: faujasite-Na, -Ca, -Na: paulingite-K. -Ca; phillipsite-Na, -Ca, -Ka; stilbite-Ca, -Na. Key references, type locality, origin of name, chemical data. IZA structure-type symbols, space-group symmetry; unit-cell dimensions, and comments on structure are listed for 13 compositional series, 82 accepted zeolite mineral species, and three of doubtful status. Herschelite, leonhardite, svetlozarite, and wellsite are discredited as mineral species names. Obsolete and discredited names are listed.

A new approach to evaluate natural zeolite ability to sorb lead (Pb) from aqueous solutions

NASA Astrophysics Data System (ADS)

Drosos, Evangelos I. P.; Karapanagioti, Hrissi K.

2013-04-01

Lead (Pb) is a hazardous pollutant commonly found in aquatic ecosystems. Among several methods available, the addition of sorbent amendments to soils or sediments is attractive, since its application is relatively simple, while it can also be cost effective when a low cost and re-usable sorbent is used; e.g. natural zeolites. Zeolites are crystalline aluminosilicates with a three-dimensional structure composed of a set of cavities occupied by large ions and water molecules. Zeolites can accommodate a wide variety of cations, such as Na+, K+, Ca2+, Mg2+, which are rather loosely held and can readily be exchanged for others in an aqueous solution. Natural zeolites are capable of removing cations, such as lead, from aqueous solutions by ion exchange. There is a wide variation in the cation exchange capacity (CEC) of natural zeolites because of the different nature of various zeolites cage structures, natural structural defects, adsorbed ions, and their associated gangue minerals. Naturally occurring zeolites are rarely pure and are contaminated to varying degrees by other minerals, such as clays and feldspars, metals, quartz, or other zeolites as well. These impurities affect the CEC even for samples originated from the same region but from a different source. CEC of the material increases with decreasing impurity content. Potentially exchangeable ions in such impurities do not necessarily participate in ion exchange mechanism, while, in some cases, impurities may additionally block the access to active sites. For zeoliferous rocks having the same percentage of a zeolitic phase, the CEC increases with decreasing Si/Al ratio, as the more Si ions are substituted by Al ions, the more negative the valence of the matrix becomes. Sodium seems to be the most effective exchangeable ion for lead. On the contrary, it is unlikely that the potassium content of the zeolite would be substituted. A pretreatment with high concentration solutions of Na, such as 2 M NaCl, can significantly improve zeolite CEC by bringing the material to near homoionic form. pH and temperature are the critical parameters for using natural zeolites as sorbents. Zeolites should not be used in extremely acidic, neither in extremely basic pH conditions, except for very short times. The exchange of Pb, requires low solution pH, to avoid precipitation but not too low because the H+ are competitive ions for ion exchange; as a result the zeolite CEC related to Pb removal may be downgraded. If pH enters the basic range (e.g. pH>8), more aquatic complexes with lower positive valence than those prevailing in lower pH are produced; these complexes are less attracted by the negative charged zeolitic matrix. Pb uptake is favored at higher temperatures as ion exchange (including the diffusion of exchangeable ions inside the material and the medium, and vice versa) is an endothermic process. With the increase of temperature there is a decrease in hydration of all available exchangeable cations that eases the movement within the channels of the solid matrix. Additionally, the mobility of the potassium ions, present in the zeolitic material, also increases with the temperature resulting in enhanced CEC.

Determination of Martian soil mineralogy and water content using the Thermal Analyzer for Planetary Soils (TAPS)

NASA Technical Reports Server (NTRS)

Gooding, James L.; Ming, Douglas W.; Allton, Judith H.; Byers, Terry B.; Dunn, Robert P.; Gibbons, Frank L.; Pate, Daniel B.; Polette, Thomas M.

1992-01-01

Physical and chemical interactions between the surface and atmosphere of Mars can be expected to embody a strong cause-and-effect relationship with the minerals comprising the martian regolith. Many of the minerals in soils and sediments are probably products of chemical weathering (involving surface/atmosphere or surface/hydrosphere reactions) that could be expected to subsequently influence the sorption of atmospheric gases and water vapor. Therefore, identification of the minerals in martian surface soils and sediments is essential for understanding both past and present interactions between the Mars surface and atmosphere. Clearly, the most definitive mineral analyses would be achieved with well-preserved samples returned to Earth-based laboratories. In advance of a Mars sample return mission, however, significant progress could be made with in situ experiments that fill current voids in knowledge about the presence or abundance of key soil minerals such as clays (layered-structured silicates), zeolites, and various salts, including carbonates. TAPS is intended to answer that challenge by providing first-order identification of soil and sediment minerals.

Influence of organic acids on kinetic release of chromium in soil contaminated with leather factory waste in the presence of some adsorbents.

PubMed

Taghipour, Marzieh; Jalali, Mohsen

2016-07-01

In this study, batch experiments were conducted to investigate the effects of nanoparticles (NPs) (MgO, ZnO, TiO2) and clay minerals (bentonite, zeolite) on the release of chromium (Cr) from leather factory waste (LFW) and LFW treated soil using organic acids. Chromium release from all treatments was studied in the presence of citric acid, oxalic acid and CaCl2 solutions. The results showed that, in all treatments, organic acids released more Cr than inorganic salt (CaCl2). The release of Cr by citric acid was higher than that by oxalic acid. In LFW treated soil and LFW, the release of Cr from the all treatments with NPs was less than that from the clay mineral treatments. On the other hand, in the presence of organic acids, Cr release by NPs and clay minerals decreased. Two kinetic models including pseudo-first- and pseudo-second-order model were tested to describe the time dependent Cr release data. Among the kinetic models used, the pseudo-second-order model generally gave the best fits to experimental data. Before and after release experiments, Cr in LFW, treated LFW, control soil and LFW treated soils were fractionated. In all treatments, the greatest amounts of Cr were found in the residual fraction (RES). The organic acids were effective in reducing the exchangeable (EXC), bound to organic matter (OM) and bound to carbonate (CAR) fractions of Cr in all treatments, whereas, after release of Cr from treated soils, Cr remained mainly in the RES fraction. The application of NPs and clay minerals in soil led to a significant transformation of Cr from mobile fractions to the RES fraction. Therefore, organic ligands played a dominant role in mobility and bioavailability of Cr and the removal of Cr by adsorbents. Copyright © 2016 Elsevier Ltd. All rights reserved.

Sorption of As(V) on aluminosilicates treated with Fe(II) nanoparticles.

PubMed

Dousová, Barbora; Grygar, Tomás; Martaus, Alexandr; Fuitová, Lucie; Kolousek, David; Machovic, Vladimír

2006-10-15

Adsorption of arsenic on clay surfaces is important for the natural and simulated removal of arsenic species from aqueous environments. In this investigation, three samples of clay minerals (natural metakaoline, natural clinoptilolite-rich tuff, and synthetic zeolite) in both untreated and Fe-treated forms were used for the sorption of arsenate from model aqueous solution. The treatment of minerals consisted of exposing them to concentrated solution of Fe(II). Within this process the mineral surface has been laden with Fe(III) oxi(hydroxides) whose high affinity for the As(V) adsorption is well known. In all investigated systems the sorption capacity of Fe(II)-treated sorbents increased significantly in comparison to the untreated material (from about 0.5 to >20.0 mg/g, which represented more than 95% of the total As removal). The changes of Fe-bearing particles in the course of treating process and subsequent As sorption were investigated by the diffuse reflectance spectroscopy and the voltammetry of microparticles. IR spectra of treated and As(V)-saturated solids showed characteristic bands caused by Fe(III)SO(4), Fe(III)O, and AsO vibrations. In untreated As(V)-saturated solids no significant AsO vibrations were observed due to the negligible content of sorbed arsenate.

Paleoenvironmental Interpretation of drill core from Tugen Hills, Kenya through X-ray Diffraction

NASA Astrophysics Data System (ADS)

Minkara, K. E.; Rabideaux, N. M.; Deocampo, D.; Kingston, J.; Cohen, A. S.

2016-12-01

Paleoenvironmental reconstruction in regions of significant archeological and paleontological discoveries can be used to help better understand early hominin history in relation to environmental changes. Using X-ray diffraction (XRD) analysis of lacustrine sediments obtained from core material recovered during the Hominin Sites and Paleolakes Drilling Project (HSPDP) campaign at the Tugen Hills drilling site in central Kenya we can reconstruct a high-resolution record of paleoclimate and tectonics from the lake sediments during the Plio-Pleistocene. XRD analysis enables us to identify the mineralogical trends from the 227m core, which can be employed to understand the geochemical evolution of the basin. We want to test whether 23-kyr precessional cyclicity is the primary driver of environmental change at Lake Baringo, and how that change influenced vertebrate and hominin evolution. Our goals are to understand how the paleolake geochemically evolved over time and how the mineralogical characteristics are related to climate change. Preliminary results indicate discrete zones of carbonate and zeolite mineral occurrence, suggesting possible paleoclimate indicators of humidity versus aridity. Geochemical and sedimentological analysis will be required to distinguish primary lacustrine carbonate versus secondary or pedogenic carbonate, which does not carry a lacustrine signal. Quartz-rich intervals and diatomaceous sequences are distinct from zeolitic zones, suggesting variable salinities. Furthermore, hkl reflections of clay-rich bulk samples suggest varying relative abundances of kaolinite and smectite. As we extract clay fractions and analyze the clay mineralogy in further detail, this ratio may provide an indicator of paleoweathering intensity within the basin.

Recommended nomenclature for zeolite minerals: Report of the Subcommittee on Zeolites of the International Mineralogical Association, Commission on New Minerals and Mineral Names

USGS Publications Warehouse

Coombs, D.S.; Alberti, A.; Armbruster, T.; Artioli, G.; Colella, C.; Galli, E.; Grice, Joel D.; Liebau, F.; Mandarino, J.A.; Minato, H.; Nickel, E.H.; Passaglia, E.; Peacor, D.R.; Quartieri, S.; Rinaldi, R.; Ross, M.; Sheppard, R.A.; Tillmanns, E.; Vezzalini, G.

1998-01-01

This report embodies recommendations on zeolite nomenclature approved by the International Mineralogical Association Commission on New Minerals and Mineral Names. In a working definition of a zeolite mineral used for this review, structures containing an interrupted containing an interrupted framework of tetrahedra are accepted where other zeolitic properties prevail, and complete substitution by elements other than Si and Al is alloowed. Separate species are recognized in topologically distinctive compositional series in which different extra-framework cations are the most abundant in atomic proportions. To name these, the appropriate chemical symbol is attached by a hyphen to the series name as a suffix, except for the names harmotome, pollucite and wairakite in the phillipsite and analcime series. Differences in space-group symmetry and in order-disorder relationships in zeolites having the same topologically distinctive framework do not in general provide adequate grounds for recognition of separate species. Zeolite species are not to be distinguished solely in Si:Al ratio except for heulandite (Si:Al < 4.0) and clinoptilolite (Si:Al ??? 4.0). Dehydration, partial hydration and over-hydration are not sufficient grounds for the recognition of separate species of zeolites. Use of the term 'ideal formula' should be avoided in referring to a simplified or averaged formula of zeolite. Newly recognized species in compositional series are as follows: brewsterite-Sr, -Ba; chabazite-Ca, -Na, -K; clinoptilolite-K, -Na, -Ca; dechiardite-Ca, -Na; erionite-Na, -K, -Ca,; faujasite-Na, -Ca, -Mg; ferrierite-Mg, -K, -Na; gmelinite-Na, -Ca, -K; heulandite-Ca, -Na, -K, -Sr; levyne-Ca, -Na; paulingite-K, -Ca; phillipsite-Na, -Ca, -K stilbite-Ca, -Na. Key references, type locality, origin of name, chemical data, IZA structure-type symbols, space-group symmetry, unit-cell dimensions, and comments on structure are listed for 13 compositional series, 82 accepted zeolite mineral species, and three of doubtful status. Herschelite, leonhardite, svetlozarite and wellsite are discredited as mineral species names. Obsolete and discredited names are listed.

Recommended nomenclature for zeolite minerals: report of the subcommittee on zeolites of the International Mineralogical Association, Commission on new Minerals and Mineral names

USGS Publications Warehouse

Coombs, D.S.; Alberti, A.; Armbruster, T.; Artioli, G.; Colella, C.; Galli, E.; Grice, Joel D.; Liebau, F.; Mandarino, J.A.; Minato, H.; Nickel, E.H.; Passaglia, E.; Peacor, D.R.; Quartieri, S.; Rinaldi, R.; Ross, M.; Sheppard, R.A.; Tillmanns, E.; Vezzalini, G.

1997-01-01

This report embodies recommendations on zeolite nomenclature approved by the International Mineralogical Association, Commission on New Minerals and Mineral Names. In a working definition of a zeolite mineral used for this review, structures containing an interrupted framework of tetrahedra are accepted where other zeolitic properties prevail, and complete substitution by elements other than Si and Al is allowed. Separate species are recognized in topologically distinctive compositional series in which different extra-framework cations are the most abundant in atomic proportions. To name these, the appropriate chemicalsymbol is attached by a hyphen to the series name as a suffix, except for the names harmotome, pollucite and wairakite in the phillipsite and analcime series. Differences in space-group symmetry and in order-disorder relationships in zeolites having the same topologically distinctive framework do not in general provide adequate grounds for recognition of separate species. Zeolite species are not to be distinguished solely on the ratio Si:Al except for heulandite (Si:Al < 4.0) and clinoptilolite (Si:Al ??? 4.0). Dehydration, partial hydration, and overhydration are not sufficient grounds for the recognition of separate species of zeolites. Use of the term 'ideal formula' should be avoided in referring to a simplified or averaged formula of a zeolite. newly recognized species in compositional series are as follows: brewsterite-Sr, -Ba, chabazite-Ca, -Na, -K, clinoptilolite-K, -Na, -Ca, dachiardite-Ca, -Na, erionite-Na, erionite-Na, -K, -Ca, faujasite-Na, -Ca, -Mg, ferrierite-Mg, -K, -Na, gmelinite-Na, -Ca, -K, heulandite-Ca, -Na, -K, -Sr, levyne-Ca, -Na, paulingite-K, -Ca, phillipsite-Na, -Ca, -K, and stilbite-Ca, -Na. Key references, type locality, origin of name, chemical data, IZA structure-type symbols, space-group symmetry, unit-cell dimensions, and comments on structure are listed for 13 compositional series, 82 accepted zeolite mineral species, and three of doubtful status. Herschelite, leonhardite, dvetlozarite, and wellsite are discredited as mineral species names. Obsolete and discredited names are listed.

Identification of Some Zeolite Group Minerals by Application of Artificial Neural Network and Decision Tree Algorithm Based on SEM-EDS Data

NASA Astrophysics Data System (ADS)

Akkaş, Efe; Evren Çubukçu, H.; Akin, Lutfiye; Erkut, Volkan; Yurdakul, Yasin; Karayigit, Ali Ihsan

2016-04-01

Identification of zeolite group minerals is complicated due to their similar chemical formulas and habits. Although the morphologies of various zeolite crystals can be recognized under Scanning Electron Microscope (SEM), it is relatively more challenging and problematic process to identify zeolites using their mineral chemical data. SEMs integrated with energy dispersive X-ray spectrometers (EDS) provide fast and reliable chemical data of minerals. However, considering elemental similarities of characteristic chemical formulae of zeolite species (e.g. Clinoptilolite ((Na,K,Ca)2 -3Al3(Al,Si)2Si13O3612H2O) and Erionite ((Na2,K2,Ca)2Al4Si14O36ṡ15H2O)) EDS data alone does not seem to be sufficient for correct identification. Furthermore, the physical properties of the specimen (e.g. roughness, electrical conductivity) and the applied analytical conditions (e.g. accelerating voltage, beam current, spot size) of the SEM-EDS should be uniform in order to obtain reliable elemental results of minerals having high alkali (Na, K) and H2O (approx. %14-18) contents. This study which was funded by The Scientific and Technological Research Council of Turkey (TUBITAK Project No: 113Y439), aims to construct a database as large as possible for various zeolite minerals and to develop a general prediction model for the identification of zeolite minerals using SEM-EDS data. For this purpose, an artificial neural network and rule based decision tree algorithm were employed. Throughout the analyses, a total of 1850 chemical data were collected from four distinct zeolite species, (Clinoptilolite-Heulandite, Erionite, Analcime and Mordenite) observed in various rocks (e.g. coals, pyroclastics). In order to obtain a representative training data set for each minerals, a selection procedure for reference mineral analyses was applied. During the selection procedure, SEM based crystal morphology data, XRD spectra and re-calculated cationic distribution, obtained by EDS have been used for the characterization of the training set. Consequently, for each zeolite species 250 EDS data (as elemental intensities) used for training and 200 ±50 analyses were tested. Finally, two prediction models were developed. The constructed models with various cross-correlation values (r) yielded an average accuracy of >91% for the best predictions using C5.0 Decision Tree algorithm and back propagation artificial neural network. Despite having similar accuracies, the developed models exhibit different prediction behaviors for some zeolite minerals. The results demonstrate that artificial neural network as a nonlinear tool and decision tree algorithm as a rule based prediction model would be employed to provide considerably efficient and reliable identification/classification of some zeolite minerals regardless of their similar elemental compositions. Keywords: mineral identification; zeolites; energy dispersive spectrometry; artificial neural networks; decision tree.

Development of high temperature liquid lubricants for low-heat rejection heavy duty diesel engines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wiczynski, T.A.; Marolewski, T.A.

1993-03-01

Objective was to develop a liquid lubricant that will allow advanced diesel engines to operate at top ring reversal temperatures approaching 500 C and lubricant sump temperatures approaching 250 C. Base stock screening showed that aromatic esters and diesters has the lowest deposit level, compared to polyol esters, poly-alpha-olefins, or refined mineral oil of comparable viscosity. Classical aryl and alkyl ZDP antiwear additives are ineffective in reducing wear with aromatic esters; the phosphate ester was a much better antiwear additive, and polyol esters are more amenable to ZDP treatment. Zeolites and clays were evaluated for filtration.

Efficiency of a multi-soil-layering system on wastewater treatment using environment-friendly filter materials.

PubMed

Ho, Chia-Chun; Wang, Pei-Hao

2015-03-23

The multi-soil-layering (MSL) system primarily comprises two parts, specifically, the soil mixture layer (SML) and the permeable layer (PL). In Japan, zeolite is typically used as the permeable layer material. In the present study, zeolite was substituted with comparatively cheaper and more environmentally friendly materials, such as expanded clay aggregates, oyster shells, and already-used granular activated carbon collected from water purification plants. A series of indoor tests indicated that the suspended solid (SS) removal efficiency of granular activated carbon was between 76.2% and 94.6%; zeolite and expanded clay aggregates achieved similar efficiencies that were between 53.7% and 87.4%, and oyster shells presented the lowest efficiency that was between 29.8% and 61.8%. Further results show that the oyster shell system required an increase of wastewater retention time by 2 to 4 times that of the zeolite system to maintain similar chemical oxygen demand (COD) removal efficiency. Among the four MSL samples, the zeolite system and granular activated carbon system demonstrated a stable NH3-N removal performance at 92.3%-99.8%. The expanded clay aggregate system present lower removal performance because of its low adsorption capacity and excessively large pores, causing NO3--N to be leached away under high hydraulic loading rate conditions. The total phosphorous (TP) removal efficiency of the MSL systems demonstrated no direct correlation with the permeable layer material. Therefore, all MSL samples achieved a TP efficiency of between 92.1% and 99.2%.

Accelerated Leach Testing of Glass (ALTGLASS): II. Mineralization of hydrogels by leachate strong bases

DOE PAGES

Jantzen, Carol M.; Trivelpiece, Cory L.; Crawford, Charles L.; ...

2017-02-18

The durability of high level nuclear waste glasses must be predicted on geological time scales. Waste glass surfaces form hydrogels when in contact with water for varying test durations. As the glass hydrogels age, some exhibit an undesirable resumption of dissolution at long times while others exhibit near steady-state dissolution, that is, nonresumption of dissolution. Resumption of dissolution is associated with the formation of zeolitic phases while nonresumption of dissolution is associated with the formation of clay minerals. Hydrogels with a stoichiometry close to that of imogolite, (Al 2O 3·Si(OH) 4), with ferrihydrite (Fe 2O 3·0.5H 2O), have been shownmore » to be associated with waste glasses that resume dissolution. Aluminosilicate hydrogels with a stoichiometry of allophane-hisingerite ((Al,Fe) 2O 3·1.3-2Si(OH) 4) have been shown to be associated with waste glasses that exhibit near steady-state dissolution at long times. These phases are all amorphous and poorly crystalline and are also found on natural weathered basalt glasses. Interaction of these hydrogels with excess alkali and OH – (strong base) in the leachates, causes the Al 2O 3· nSiO 2 (where n=1-2) hydrogels to mineralize to zeolites. Excess alkali in the leachate is generated by alkali in the glass. As a result, preliminary rate-determining leach layer forming exchange reactions are hypothesized based on these findings.« less

Accelerated Leach Testing of Glass (ALTGLASS): II. Mineralization of hydrogels by leachate strong bases

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jantzen, Carol M.; Trivelpiece, Cory L.; Crawford, Charles L.

The durability of high level nuclear waste glasses must be predicted on geological time scales. Waste glass surfaces form hydrogels when in contact with water for varying test durations. As the glass hydrogels age, some exhibit an undesirable resumption of dissolution at long times while others exhibit near steady-state dissolution, that is, nonresumption of dissolution. Resumption of dissolution is associated with the formation of zeolitic phases while nonresumption of dissolution is associated with the formation of clay minerals. Hydrogels with a stoichiometry close to that of imogolite, (Al 2O 3·Si(OH) 4), with ferrihydrite (Fe 2O 3·0.5H 2O), have been shownmore » to be associated with waste glasses that resume dissolution. Aluminosilicate hydrogels with a stoichiometry of allophane-hisingerite ((Al,Fe) 2O 3·1.3-2Si(OH) 4) have been shown to be associated with waste glasses that exhibit near steady-state dissolution at long times. These phases are all amorphous and poorly crystalline and are also found on natural weathered basalt glasses. Interaction of these hydrogels with excess alkali and OH – (strong base) in the leachates, causes the Al 2O 3· nSiO 2 (where n=1-2) hydrogels to mineralize to zeolites. Excess alkali in the leachate is generated by alkali in the glass. As a result, preliminary rate-determining leach layer forming exchange reactions are hypothesized based on these findings.« less

Efficiency of a Multi-Soil-Layering System on Wastewater Treatment Using Environment-Friendly Filter Materials

PubMed Central

Ho, Chia-Chun; Wang, Pei-Hao

2015-01-01

The multi-soil-layering (MSL) system primarily comprises two parts, specifically, the soil mixture layer (SML) and the permeable layer (PL). In Japan, zeolite is typically used as the permeable layer material. In the present study, zeolite was substituted with comparatively cheaper and more environmentally friendly materials, such as expanded clay aggregates, oyster shells, and already-used granular activated carbon collected from water purification plants. A series of indoor tests indicated that the suspended solid (SS) removal efficiency of granular activated carbon was between 76.2% and 94.6%; zeolite and expanded clay aggregates achieved similar efficiencies that were between 53.7% and 87.4%, and oyster shells presented the lowest efficiency that was between 29.8% and 61.8%. Further results show that the oyster shell system required an increase of wastewater retention time by 2 to 4 times that of the zeolite system to maintain similar chemical oxygen demand (COD) removal efficiency. Among the four MSL samples, the zeolite system and granular activated carbon system demonstrated a stable NH3-N removal performance at 92.3%–99.8%. The expanded clay aggregate system present lower removal performance because of its low adsorption capacity and excessively large pores, causing NO3−-N to be leached away under high hydraulic loading rate conditions. The total phosphorous (TP) removal efficiency of the MSL systems demonstrated no direct correlation with the permeable layer material. Therefore, all MSL samples achieved a TP efficiency of between 92.1% and 99.2%. PMID:25809517

Development of electroactive polymer nanocomposites with porous structured materials

NASA Astrophysics Data System (ADS)

Lopes, Ana Catarina Teixeira Castro

Electroactive polymer composites are interesting materials for advance technological applications due to the possibility to combine the electroactive properties of the polymer matrix with a large variety of fillers that allow tailored responses for specific applications. The best all-around electroactive polymers are poly(vinylidene fluoride) (PVDF) and its copolymers which allied with the properties of porous zeolite materials, with tailored shape, size and Si/Al ratio, among others, leads to the possibility of development of promising PVDF/zeolite composites. In this way, a study of the structural, thermal and electrical properties of PVDF composites prepared with different framework zeolite types (LTL, LTA, FAU and MFI), different polymer solvents (DMF, DMSO, TEP) and different zeolite (NaY) concentrations (4, 16, 24 and 32 wt %) was performed. Further, the dielectric response, electrical conductivity and electric modulus of the composites were investigated as a function of NaYzeolite content. The zeolite influence on the electroactive gamma-phase crystallization of PVDF was explored, as well as the effect of clay layered structure (Montmorillonite, Kaolinite and Laponite) on the electroactive gamma-phase nucleation and on the optical transparency of the composite. It was found that the obtained composites showed an electrical response dependence on the pore structure and chemical content of the inorganic host. The dielectric response of the composites is directly related to the Si/Al ratio, leading zeolites with lower Si/Al ratios to larger dielectric responses and encapsulation efficiencies in the composites. It was also found that the zeolite content strongly influences the macroscopic response of dielectric response, which increases for increasing filler content. The dielectric constant at room temperature reaches values larger than 1000 for the 32 wt.% composite at 1 kHz what is mainly attributed to restricted ion mobility and interfacial polarization effects due to the zeolite inclusion, leading also to high dielectric losses. For the higher zeolite concentrations the composite d.c. electrical conductivity is characterized by two conducting regimes separated by a concentration independent breaking voltage of 4 V, which is associated to an intrazeolite charge transport. Dielectric relaxation studies show that the main relaxation process (?-relaxation) of the amorphous phase of the polymer matrix is not affected by the presence of the zeolite and, in a similar way, the zeolite low temperature relaxation is not significantly affected by the polymer phase. On the other hand, the electric modulus formalism reveals significant contributions of the fillers to the electrical permittivity and conductivity of the composites. The presence of the zeolite particles increases a.c. conductivity and the Maxwell-Wagner-Sillars contribution that is predominant at low frequencies with respect to the ohmic contribution to permittivity. The ability of zeolites to induce the eletroactive gamma-phase nucleation of PVDF is directly dependent on the Si/Al ratio and zeolite content; however it only occurs when the composite is melted at temperatures below 200 ºC. The complete ?-phase crystallization of the polymer crystalline phase occurs for a filler content of 16 wt% of LTA or FAU zeolite structure. The even higher surface interaction of clays when exfoliated leads to the same phenomenon with an amount of 0.50 % of Montmorillonite clay content. The electroactivity of the material has been proven by measuring the piezoelectric d33 response of the material, which presents a value of -7 pC/N, lower than for beta-PVDF obtained by mechanical stretching but still among the largest coefficients obtained for polymers. Further, the optical transmittance in the visible range is strongly enhanced with respect to the transmittance of the pure polymer. The development, characterization and physical-chemical understanding of these PVDF/zeolite and PVDF/clay composites resulted in suitable materials for applications in diverse areas including battery separator membranes and biomedical applications.

Improved synthesis of isostearic acid using zeolite catalysts

USDA-ARS?s Scientific Manuscript database

Isostearic acids are unique and important biobased products with superior properties. Unfortunately, they are not widely utilized in industry because they are produced as byproducts from a process called clay-catalyzed oligomerization of tall oil fatty acids. Generally, this clay method results in...

Fluids in Convergent Margins: What do We Know about their Composition, Origin, Role in Diagenesis and Importance for Oceanic Chemical Fluxes?

NASA Astrophysics Data System (ADS)

Kastner, M.; Elderfield, H.; Martin, J. B.

1991-05-01

The nature and origin of fluids in convergent margins can be inferred from geochemical and isotopic studies of the venting and pore fluids, and is attempted here for the Barbados Ridge, Nankai Trough and the convergent margin off Peru. Venting and pore fluids with lower than seawater Cl- concentrations characterize all these margins. Fluids have two types of source: internal and external. The three most important internal sources are: (1) porosity reduction; (2) diagenetic and metamorphic dehydration; and (3) the breakdown of hydrous minerals. Gas hydrate formation and dissociation, authigenesis of hydrous minerals and the alteration of volcanic ash and/or the upper oceanic crust lead to a redistribution of the internal fluids and gases in vertical and lateral directions. The maximum amount of expelled water calculated can be ca. 7 m3 a-1 m-1, which is much less than the tens to more than 100 m3 a-1 m-1 of fluid expulsion which has been observed. The difference between these figures must be attributed to external fluid sources, mainly by transport of meteoric water enhanced by mixing with seawater. The most important diagenetic reactions which modify the fluid compositions, and concurrently the physical and even the thermal properties of the solids through which they flow are: (1) carbonate recrystallization, and more importantly precipitation; (2) bacterial and thermal degradation of organic matter; (3) formation and dissociation of gas hydrates; (4) dehydration and transformation of hydrous minerals, especially of clay minerals and opal-A; and (5) alteration, principally zeolitization and clay mineral formation, of volcanic ash and the upper oceanic crust.

Rare earth elements upon assessment of reasons of the geophagy in Sikhote-Alin region (Russian Federation), Africa and other world regions.

PubMed

Panichev, Alexander M; Popov, Vladimir K; Chekryzhov, Igor Yu; Seryodkin, Ivan V; Stolyarova, Tatiana A; Zakusin, Sergey V; Sergievich, Alexandr A; Khoroshikh, Pavel P

2016-12-01

Rocks eaten by wild animals on the Bolshoy Shanduyskiy kudur in the Sikhote-Alin region (Russian Federation) are zeolite-clay mineral complexes-products of weathering of zeolitized vitric tuffs of rhyolite composition, deposited in aqueous medium within the volcanic caldera of about 55 million years ago. By composition of rock-forming oxides, the tuffs refer to high-potassium calc-alkaline series. In trace elements of most favorite kudurites of the Bolshoy Shanduyskiy kudur, there are significantly increased contents of most of rare earth elements (2-5 times in comparison with surrounding rocks). The results of our analysis of geological and geochemical data on kudurs and kudurites in another part of the Sikhote-Alin, as well as on other regions of the world (particularly, in Africa and Indonesia), taking into account new data on the prevalence of rare earth elements in living matter and their medical and biological properties, enable us to consider the version of causal connection of the geophagy with rare earth elements.

Chemical Evidence for Smectites and Zeolites on Mars: Criteria and Limitations

NASA Technical Reports Server (NTRS)

Clark, B. C.; Ming, D.; Vaniman, D.; Wiens, R.; Gellert, R.; Bridges, J. C.; Morris, D.

2014-01-01

Aqueous alteration on Mars can produce a range of tell-tale secondary minerals [1]. Surface missions typically obtain detailed and highly localized element compositional information, but not always mineralogical information, whereas orbital missions deduce mineralogy from relatively high spatial resolution IR spectral mapping (decameters scale, for CRISM), but obtain element data only over much larger areas of martian terrain (200 km). Surface missions have also discovered several occurrences of major geochemical alteration of igneous precursors, for many of which elemental compositional is the only diagnostic information available. Many types of clays and zeolites have quasi-unique element profiles which may be used to implicate their presence. In some cases, one or more candidate minerals are sufficiently close in their component elements and their stoichiometry that ambiguity must remain, unless other constraints can be brought to bear. Geochemical characteristics of alteration products most likely on Mars can be compared to results from MER and MSL rover missions (e.g. Independence [4] and Esperance samples). These considerations are needed for MER Opportunity rover now that Mini-TES is no longer operational. It also has importance for exploration by the MSL Curiosity rover because inferences and deductions available from ChemCam (CCAM) remote LIBS and/or in situ x-ray fluorescence (APXS) can be used as indicators for triage to select materials to sample for limited-resource instruments, SAM and Chemin.

Moderate-temperature zeolitic alteration in a cooling pyroclastic deposit

USGS Publications Warehouse

Levy, S.S.; O'Neil, J.R.

1989-01-01

The locally zeolitized Topopah Spring Member of the Paintbrush Tuff (13 Myr.), Yucca Mountain, Nevada, U.S.A., is part of a thick sequence of zeolitized pyroclastic units. Most of the zeolitized units are nonwelded tuffs that were altered during low-temperature diagenesis, but the distribution and textural setting of zeolite (heulandite-clinoptilolite) and smectite in the densely welded Topopah Spring tuff suggest that these hydrous minerals formed while the tuff was still cooling after pyroclastic emplacement and welding. The hydrous minerals are concentrated within a transition zone between devitrified tuff in the central part of the unit and underlying vitrophyre. Movement of liquid and convected heat along fractures from the devitrified tuff to the ritrophyre caused local devitrification and hydrous mineral crystallization. Oxygen isotope geothermometry of cogenetic quartz confirms the nondiagenetic moderate temperature origin of the hydrous minerals at temperatures of ??? 40-100??C, assuming a meteoric water source. The Topopah Spring tuff is under consideration for emplacement of a high-level nuclear waste repository. The natural rock alteration of the cooling pyroclastic deposit may be a good natural analog for repository-induced hydrothermal alteration. As a result of repository thermal loading, temperatures in the Topopah Spring vitrophyre may rise sufficiently to duplicate the inferred temperatures of natural zeolitic alteration. Heated water moving downward from the repository into the vitrophyre may contribute to new zeolitic alteration. ?? 1989.

Origins of saline fluids at convergent margins

NASA Astrophysics Data System (ADS)

Martin, Jonathan B.; Kastner, Miriam; Egeberg, Per Kr.

The compositions of pore and venting fluids at convergent margins differ from seawater values, reflecting mixing and diagenesis. Most significantly, the concentration of Cl-, assumed to be a conservative ion, differs from its seawater value. Chloride concentrations could be elevated by four processes, although two, the formation of gas hydrate and ion filtration by clay membranes, are insignificant in forming saline fluids at convergent margins. During the formation of gas hydrate, the resulting Cl--rich fluids, estimated to contain an average excess of ˜140 mM Cl- over seawater value, probably would be flushed from the sediment when the pore fluids vent to seawater. Ion filtration by clay membranes requires compaction pressures typical of >2 km burial depths. Even at these depths, the efficiency of ion filtration will be negligible because (1) fluids will flow through fractures, thereby bypassing clay membranes, (2) concentrations of clay minerals are diluted by other phases, and (3) during burial, smectite converts to illite, which has little capacity for ion filtration. A third process, mixing with subaerially evaporated seawater, elevates Cl- concentrations to 1043 mM in forearc basins along the Peru margin. Evaporation of seawater, however, will be important only in limited geographic regions that are characterized by enclosed basins, arid climates, and permeable sediments. At the New Hebrides and Izu-Bonin margins, Cl- concentrations are elevated to a maximum of 1241 mM. The process responsible for this increase is the alteration of volcanic ash to hydrous clay and zeolite minerals. Mass balance calculations, based on the decrease in δ18O values to -9.5‰ (SMOW), suggest that the Cl- concentrations could increase solely from the formation of smectite in a closed system. The diagenesis of volcanic ash also alters the concentrations of most dissolved species in addition to Cl-. Depending on the volume of this altered fluid, it could influence seawater chemistry when vented from the sediment.

Mineral resource of the month: natural and synthetic zeolites

USGS Publications Warehouse

Virta, Robert L.

2008-01-01

Volcanic rocks containing natural zeolites — hydrated aluminosilicate minerals that contain alkaline and alkaline-earth metals — have been mined worldwide for more than 1,000 years for use as cements and building stone. For centuries, people thought natural zeolites occurred only in small amounts inside cavities of volcanic rock. But in the 1950s and early 1960s, large zeolite deposits were discovered in volcanic tuffs in the western United States and in marine tuffs in Italy and Japan. And since then, similar deposits have been found around the world, from Hungary to Cuba to New Zealand. The discovery of these larger deposits made commercial mining of natural zeolite possible.

Staging Life in an Early Warm ‘Seltzer’ Ocean

DOE PAGES

Schoonen, Martin; Smirnov, Alexander

2016-12-01

A period as short as 20 million years within the first 100 million years after the formation of the Moon may have set the stage for the origin of life. This atmosphere contained more carbon dioxide than any other period afterwards. The carbon dioxide sustained greenhouse conditions, accelerated the weathering of a primitive crust and may have led to conditions conducive to the formation of the building blocks of life. The conversion of CO 2 as well as N 2 may have been facilitated by clays, zeolites, sulfides and metal alloys formed as the crust reacted with a warm ‘seltzer’more » ocean. We used geochemical modeling to constrain the conditions favorable for the formation of these potential mineral catalysts.« less

Staging Life in an Early Warm ‘Seltzer’ Ocean

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schoonen, Martin; Smirnov, Alexander

A period as short as 20 million years within the first 100 million years after the formation of the Moon may have set the stage for the origin of life. This atmosphere contained more carbon dioxide than any other period afterwards. The carbon dioxide sustained greenhouse conditions, accelerated the weathering of a primitive crust and may have led to conditions conducive to the formation of the building blocks of life. The conversion of CO 2 as well as N 2 may have been facilitated by clays, zeolites, sulfides and metal alloys formed as the crust reacted with a warm ‘seltzer’more » ocean. We used geochemical modeling to constrain the conditions favorable for the formation of these potential mineral catalysts.« less

Destabilization of emulsions by natural minerals.

PubMed

Yuan, Songhu; Tong, Man; Wu, Gaoming

2011-09-15

This study developed a novel method to destabilize emulsions and recycle oils, particularly for emulsified wastewater treatment. Natural minerals were used as demulsifying agents, two kinds of emulsions collected from medical and steel industry were treated. The addition of natural minerals, including artificial zeolite, natural zeolite, diatomite, bentonite and natural soil, could effectively destabilize both emulsions at pH 1 and 60 °C. Over 90% of chemical oxygen demand (COD) can be removed after treatment. Medical emulsion can be even destabilized by artificial zeolite at ambient temperature. The mechanism for emulsion destabilization by minerals was suggested as the decreased electrostatic repulsion at low pH, the enhanced gathering of oil microdroplets at elevated temperature, and the further decreased surface potential by the addition of minerals. Both flocculation and coalescence were enhanced by the addition of minerals at low pH and elevated temperature. Copyright © 2011 Elsevier B.V. All rights reserved.

Mineral Acquisition from Clay by Budongo Forest Chimpanzees.

PubMed

Reynolds, Vernon; Lloyd, Andrew W; English, Christopher J; Lyons, Peter; Dodd, Howard; Hobaiter, Catherine; Newton-Fisher, Nicholas; Mullins, Caroline; Lamon, Noemie; Schel, Anne Marijke; Fallon, Brittany

2015-01-01

Chimpanzees of the Sonso community, Budongo Forest, Uganda were observed eating clay and drinking clay-water from waterholes. We show that clay, clay-rich water, and clay obtained with leaf sponges, provide a range of minerals in different concentrations. The presence of aluminium in the clay consumed indicates that it takes the form of kaolinite. We discuss the contribution of clay geophagy to the mineral intake of the Sonso chimpanzees and show that clay eaten using leaf sponges is particularly rich in minerals. We show that termite mound soil, also regularly consumed, is rich in minerals. We discuss the frequency of clay and termite soil geophagy in the context of the disappearance from Budongo Forest of a formerly rich source of minerals, the decaying pith of Raphia farinifera palms.

Mineral Acquisition from Clay by Budongo Forest Chimpanzees

PubMed Central

Reynolds, Vernon; Lloyd, Andrew W.; English, Christopher J.; Lyons, Peter; Dodd, Howard; Hobaiter, Catherine; Newton-Fisher, Nicholas; Mullins, Caroline; Lamon, Noemie; Schel, Anne Marijke; Fallon, Brittany

2015-01-01

Chimpanzees of the Sonso community, Budongo Forest, Uganda were observed eating clay and drinking clay-water from waterholes. We show that clay, clay-rich water, and clay obtained with leaf sponges, provide a range of minerals in different concentrations. The presence of aluminium in the clay consumed indicates that it takes the form of kaolinite. We discuss the contribution of clay geophagy to the mineral intake of the Sonso chimpanzees and show that clay eaten using leaf sponges is particularly rich in minerals. We show that termite mound soil, also regularly consumed, is rich in minerals. We discuss the frequency of clay and termite soil geophagy in the context of the disappearance from Budongo Forest of a formerly rich source of minerals, the decaying pith of Raphia farinifera palms. PMID:26218593

[Interaction of clay minerals with microorganisms: a review of experimental data].

PubMed

Naĭmark, E B; Eroshchev-Shak, V A; Chizhikova, N P; Kompantseva, E I

2009-01-01

A review of publications containing results of experiments on the interaction of microorganisms with clay minerals is presented. Bacteria are shown to be involved in all processes related to the transformation of clay minerals: formation of clays from metamorphic and sedimentary rocks, formation of clays from solutions, reversible transitions of different types of clay minerals, and consolidation of clay minerals into sedimentary rocks. Integration of these results allows to conclude that bacteria reproduced all possible abiotic reactions associated with the clay minerals, these reactions proceed much faster with the bacteria being involved. Thus, bacteria act as a living catalyst in the geochemical cycle of clay minerals. The ecological role of bacteria can be considered as a repetition of a chemical process of the abiotic world, but with the use of organic catalytic innovation.

The Performance of Four Different Mineral Liners on the Transportation of Chlorinated Phenolic Compounds to Groundwater in Landfills

PubMed Central

Adar, Elanur; Bilgili, Mehmet Sinan

2015-01-01

The aim of this study was to investigate the efficiency of four different mineral liners (clay, bentonite, kaoline, and zeolite) which could be utilized to prevent the transport of phenolic compounds to groundwater through alternative liner systems. Four laboratory-scale HDPE reactors with 80 cm height and 40 cm inner diameter were operated for a period of 180 days. Results indicated that the transport of mono- or dichlorophenols is significantly prevented by the liner systems used, while the transport of highly chlorinated phenolic compounds cannot be prevented by the landfill liner system effectively. Highly chlorinated phenolic compounds in groundwater can be found in higher concentrations than the leachate, as a result of the degradation and transformation of these compounds. Thus, the analysis of highly chlorinated phenolic compounds such as 2,4,6-TCP, 2,3,6-TCP, 3,4,5-TCP, and PCP is of great significance for the studies to be conducted on the contamination of groundwater around landfills. PMID:26759828

Hydrothermal synthesis of free-template zeolite T from kaolin

NASA Astrophysics Data System (ADS)

Arshad, Sazmal E.; Yusslee, Eddy F.; Rahman, Md. Lutfor; Sarkar, Shaheen M.; Patuwan, Siti Z.

2017-12-01

Free-template zeolite T crystals were synthesized via hydrothermal synthesis by utilizing the activated kaolin as silica and alumina source, with the molar composition of 1 SiO2: 0.04 Al2O3: 0.26 Na2O: 0.09 K2O: 14 H2O. Observation of the formation of free-template zeolite crystals were done at temperature 90°C, 100 °C and 110 °C respectively. It was therefore determined that during the 120 h of the synthesis at 90 °C, zeolite T nucleated and formed a first competitive phase with zeolite L. As temperature increases to 100 °C, zeolite T presented itself as a major phase in the system at time 168 h. Subsequently, development of Zeolite T with second competitive phase of zeolite W was observed at temperature 110 °C. In this study, XRD and SEM instruments were used to monitor the behavior of zeolite T crystals with respect of temperature and time. By using natural resource of kaolin clay as a starting material, this paper hence aims to provide new findings in synthesis of zeolite T using low energy consumption and low production cost.

Clay mineral type effect on bacterial enteropathogen survival in soil.

PubMed

Brennan, Fiona P; Moynihan, Emma; Griffiths, Bryan S; Hillier, Stephen; Owen, Jason; Pendlowski, Helen; Avery, Lisa M

2014-01-15

Enteropathogens released into the environment can represent a serious risk to public health. Soil clay content has long been known to have an important effect on enteropathogen survival in soil, generally enhancing survival. However, clay mineral composition in soils varies, and different clay minerals have specific physiochemical properties that would be expected to impact differentially on survival. This work investigated the effect of clay materials, with a predominance of a particular mineral type (montmorillonite, kaolinite, or illite), on the survival in soil microcosms over 96 days of Listeria monocytogenes, Salmonella Dublin, and Escherichia coli O157. Clay mineral addition was found to alter a number of physicochemical parameters in soil, including cation exchange capacity and surface area, and this was specific to the mineral type. Clay mineral addition enhanced enteropathogen survival in soil. The type of clay mineral was found to differentially affect enteropathogen survival and the effect was enteropathogen-specific. © 2013.

Impact-Induced Clay Mineral Formation and Distribution on Mars

NASA Technical Reports Server (NTRS)

Rivera-Valentin, E. G.; Craig, P. I.

2015-01-01

Clay minerals have been identified in the central peaks and ejecta blankets of impact craters on Mars. Several studies have suggested these clay minerals formed as a result of impact induced hydrothermalism either during Mars' Noachian era or more recently by the melting of subsurface ice. Examples of post-impact clay formation is found in several locations on Earth such as the Mjolnir and Woodleigh Impact Structures. Additionally, a recent study has suggested the clay minerals observed on Ceres are the result of impact-induced hydrothermal processes. Such processes may have occurred on Mars, possibly during the Noachian. Distinguishing between clay minerals formed preor post-impact can be accomplished by studying their IR spectra. In fact, showed that the IR spectra of clay minerals is greatly affected at longer wavelengths (i.e. mid-IR, 5-25 micron) by impact-induced shock deformation while the near-IR spectra (1.0-2.5 micron) remains relatively unchanged. This explains the discrepancy between NIR and MIR observations of clay minerals in martian impact craters noted. Thus, it allows us to determine whether a clay mineral formed from impact-induced hydrothermalism or were pre-existing and were altered by the impact. Here we study the role of impacts on the formation and distribution of clay minerals on Mars via a fully 3-D Monte Carlo cratering model, including impact- melt production using results from modern hydrocode simulations. We identify regions that are conducive to clay formation and the location of clay minerals post-bombardment.

Impact mineralogy and chemistry of the cretaceous-tertiary boundary at DSDP site 576

NASA Technical Reports Server (NTRS)

Bostwick, Jennifer A.; Kyte, Frank T.

1993-01-01

We have identified the K/T boundary in pelagic clay sediments from cores at DSDP Site 576 in the western North Pacific. Detailed geochemical and trace mineralogical analyses of this boundary section are in progress and initial results indicate similarities and differences relative to the only other clay core investigated in detail; DSDP Site 596, a locality in the western South Pacific. Peak Ir concentrations of 13 ng/g in DSDP Hole 576B are virtually identical with those observed in the South Pacific, but in the North Pacific this peak is much narrower and the integrated Ir fluence of 85 ng cm(exp -2) is 4 times lower (320 in Hole 596). Of the 34 elements measured, only Ir and Cr were found to have anomalous concentrations in K/T boundary samples. Trace mineral residues were obtained by washing away clays and sequential chemical leaches (including HF) to remove typical hydrogenous and biogenous sediment components (e.g., zeolites and radiolarian opal). We attempted to quantitatively recover the entire trace mineral assemblage for grains greater than 30 micrometers in diameter. Our mineral residues were dominated by two phases: quartz and magnesioferrite spinel. Other non-opaque mineral grains we have positively identified were trace K-feldspar, plagioclase, corundum, and muscovite. Of these only K-feldspar exhibited planar deformation features (PDF). We have not found abundant plagioclase, as in the South Pacific suggesting that this phase was either not preserved in the North Pacific, or that in the south, it has a non-impact (i.e., volcanic) source. PDF in quartz were commonly obscured by secondary overgrowths on the surfaces of quartz grains, presumably from diagenetic reprecipitation of silica dissolved from opaline radiolarian tests that are common in these sediments. However, careful examination revealed that most grains had multiple sets of PDF. Of the 133 quartz grains greater than 30 micrometers analyzed, 62 percent showed evidence of shock. The largest shocked grain recovered to date had a maximum diameter of 160 micrometers, consistent with other sites in the Pacific.

Surface clay formation during short-term warmer and wetter conditions on a largely cold ancient Mars

NASA Astrophysics Data System (ADS)

Bishop, Janice L.; Fairén, Alberto G.; Michalski, Joseph R.; Gago-Duport, Luis; Baker, Leslie L.; Velbel, Michael A.; Gross, Christoph; Rampe, Elizabeth B.

2018-03-01

The ancient rock record for Mars has long been at odds with climate modelling. The presence of valley networks, dendritic channels and deltas on ancient terrains points towards running water and fluvial erosion on early Mars1, but climate modelling indicates that long-term warm conditions were not sustainable2. Widespread phyllosilicates and other aqueous minerals on the Martian surface3-6 provide additional evidence that an early wet Martian climate resulted in surface weathering. Some of these phyllosilicates formed in subsurface crustal environments5, with no association with the Martian climate, while other phyllosilicate-rich outcrops exhibit layered morphologies and broad stratigraphies7 consistent with surface formation. Here, we develop a new geochemical model for early Mars to explain the formation of these clay-bearing rocks in warm and wet surface locations. We propose that sporadic, short-term warm and wet environments during a generally cold early Mars enabled phyllosilicate formation without requiring long-term warm and wet conditions. We conclude that Mg-rich clay-bearing rocks with lateral variations in mixed Fe/Mg smectite, chlorite, talc, serpentine and zeolite occurrences formed in subsurface hydrothermal environments, whereas dioctahedral (Al/Fe3+-rich) smectite and widespread vertical horizonation of Fe/Mg smectites, clay assemblages and sulphates formed in variable aqueous environments on the surface of Mars. Our model for aluminosilicate formation on Mars is consistent with the observed geological features, diversity of aqueous mineralogies in ancient surface rocks and state-of-the-art palaeoclimate scenarios.

Multifaceted role of clay minerals in pharmaceuticals

PubMed Central

Khurana, Inderpreet Singh; Kaur, Satvinder; Kaur, Harpreet; Khurana, Rajneet Kaur

2015-01-01

The desirable physical and physiochemical properties of clay minerals have led them to play a substantial role in pharmaceutical formulations. Clay minerals like kaolin, smectite and palygorskite-sepiolite are among the world's most valuable industrial minerals and of considerable importance. The elemental features of clay minerals which caused them to be used in pharmaceutical formulations are high specific area, sorption capacity, favorable rheological properties, chemical inertness, swelling capacity, reactivity to acids and inconsiderable toxicity. Of course, these are highly cost effectual. This special report on clay minerals provides a bird's eye view of the chemical composition and structure of these minerals and their influence on the release properties of active medicinal agents. Endeavor has been made to rope in myriad applications depicting the wide acceptability of these clay minerals. PMID:28031881

Interstitial Water Geochemistry and Low Temperature Alteration in Volcaniclastic Sediments from the Amami Sankaku Basin at IODP Site U1438 (Expedition 351)

NASA Astrophysics Data System (ADS)

Loudin, L. C.; Yogodzinski, G. M.; Sena, C.; van der Land, C.; Zhang, Z.; Marsaglia, K. M.; Meffre, S.

2014-12-01

Interstitial water (IW) geochemistry provides insight into the diagenetic transformation of sediment to rock by component dissolution/alteration and precipitation of new mineral phases as pore-filling cements, as well as providing insight into ion exchange reactions with secondary minerals. At Site U1438, 67 IW samples were collected within a ~950 m section of volcaniclastic sediments. These were analyzed for pH as well as major and trace elements. The corresponding host sediments were mineralogically characterized by XRD and petrographic observations. Three alteration zones are inferred: 1) the upper alteration zone (~0-300 mbsf) characterized by maximum IW concentrations of Si (790.1 μM), Sr (138.5 μM) and Mn (279.5 μM), consistent with volcanic glass and siliceous microfossil dissolution, enhanced reduction of Mn oxides, and carbonate recrystallization. Maximum concentrations in Li and B coupled with the lowest pH (6.7) imply that Li and B are released into the IW due to silicate dissolution and clay desorption. 2) At intermediate depths (~300 to ~550 mbsf) Mg, K, Sr, Si, Mn, Li, and B are at concentration minima, possibly due to growth of authigenic minerals. B and Li minimum concentrations occur at high pH (~9) suggesting that these elements are preferentially removed from high pH waters during the precipitation of clay mineral and zeolite cements in primary and secondary (dissolution) pores. The mineralogy of these phases is confirmed by XRD data, and their pore-filling nature is seen in thin sections of the coarser lithologies. 3) The deep alteration zone (>~550m) is characterized by an increase in B, Li, Sr and Ca. At ~650 mbsf, Ca becomes the dominant cation in solution consistent with either mineral interaction with the IW, or diffusive input from underlying igneous basement (~1400 mbsf).

Towards an understanding of the role of clay minerals in crude oil formation, migration and accumulation

NASA Astrophysics Data System (ADS)

Wu, Lin Mei; Zhou, Chun Hui; Keeling, John; Tong, Dong Shen; Yu, Wei Hua

2012-12-01

This article reviews progress in the understanding of the role of clay minerals in crude oil formation, migration and accumulation. Clay minerals are involved in the formation of kerogen, catalytic cracking of kerogen into petroleum hydrocarbon, the migration of crude oil, and the continued change to hydrocarbon composition in underground petroleum reservoirs. In kerogen formation, clay minerals act as catalysts and sorbents to immobilize organic matter through ligand exchange, hydrophobic interactions and cation bridges by the mechanisms of Maillard reactions, polyphenol theory, selective preservation and sorptive protection. Clay minerals also serve as catalysts in acid-catalyzed cracking of kerogen into petroleum hydrocarbon through Lewis and Brønsted acid sites on the clay surface. The amount and type of clay mineral affect the composition of the petroleum. Brønsted acidity of clay minerals is affected by the presence and state of interlayer water, and displacement of this water is a probable driver in crude oil migration from source rocks. During crude oil migration and accumulation in reservoirs, the composition of petroleum is continually modified by interaction with clay minerals. The clays continue to function as sorbents and catalysts even while they are being transformed by diagenetic processes. The detail of chemical interactions and reaction mechanisms between clay minerals and crude oil formation remains to be fully explained but promises to provide insights with broader application, including catalytic conversion of biomass as a source of sustainable energy into the future.

Understanding the role of clay minerals in the chromium(VI) bioremoval by Pseudomonas aeruginosa CCTCC AB93066 under growth condition: microscopic, spectroscopic and kinetic analysis.

PubMed

Kang, Chunxi; Wu, Pingxiao; Li, Yuewu; Ruan, Bo; Li, Liping; Tran, Lytuong; Zhu, Nengwu; Dang, Zhi

2015-11-01

Laboratory batch experiments were conducted to investigate the role of clay minerals, e.g., kaolinite and vermiculite, in microbial Cr(VI) reduction by Pseudomonas aeruginosa under growth condition in glucose-amended mediums as a method for treating Cr(VI)-contaminated subsurface environment such as soil. Our results indicated that glucose could acted as an essential electron donor, and clay minerals significantly enhanced microbial Cr(VI) reduction rates by improving the consumption rate of glucose and stimulating the growth and propagation of P. aeruginosa. Cr(VI) bioreduction by both free cells and clay minerals-amended cells followed the pseudo-first-order kinetic model, with the latter one fitting better. The mass balance analyses and X-ray photoelectron spectroscopy analysis found that Cr(VI) was reduced to Cr(III) and the adsorption of total chromium on clay minerals-bacteria complex was small, implying that Cr(VI) bioremoval was not mainly due to the adsorption of Cr(VI) onto cells or clay minerals or clay minerals-cells complex but mainly due to the Cr(VI) reduction capacity of P. aeruginosa under the experimental conditions studied (e.g., pH 7). Atomic force microscopy revealed that the addition of clay minerals (e.g. vermiculite) decreased the surface roughness of Cr(VI)-laden cells and changed the cell morphology and dimension. Fourier transform infrared spectroscopy revealed that organic matters such as aliphatic species and/or proteins played an important role in the combination of cells and clay minerals. Scanning electron microscopy confirmed the attachment of cells on the surface of clay minerals, indicating that clay minerals could provide a microenvironment to protect cells from Cr(VI) toxicity and serve as growth-supporting materials. These findings manifested the underlying influence of clay minerals on microbial reduction of Cr(VI) and gave an understanding of the interaction between pollutants, the environment and the biota.

Reconstruction of a digital core containing clay minerals based on a clustering algorithm.

PubMed

He, Yanlong; Pu, Chunsheng; Jing, Cheng; Gu, Xiaoyu; Chen, Qingdong; Liu, Hongzhi; Khan, Nasir; Dong, Qiaoling

2017-10-01

It is difficult to obtain a core sample and information for digital core reconstruction of mature sandstone reservoirs around the world, especially for an unconsolidated sandstone reservoir. Meanwhile, reconstruction and division of clay minerals play a vital role in the reconstruction of the digital cores, although the two-dimensional data-based reconstruction methods are specifically applicable as the microstructure reservoir simulation methods for the sandstone reservoir. However, reconstruction of clay minerals is still challenging from a research viewpoint for the better reconstruction of various clay minerals in the digital cores. In the present work, the content of clay minerals was considered on the basis of two-dimensional information about the reservoir. After application of the hybrid method, and compared with the model reconstructed by the process-based method, the digital core containing clay clusters without the labels of the clusters' number, size, and texture were the output. The statistics and geometry of the reconstruction model were similar to the reference model. In addition, the Hoshen-Kopelman algorithm was used to label various connected unclassified clay clusters in the initial model and then the number and size of clay clusters were recorded. At the same time, the K-means clustering algorithm was applied to divide the labeled, large connecting clusters into smaller clusters on the basis of difference in the clusters' characteristics. According to the clay minerals' characteristics, such as types, textures, and distributions, the digital core containing clay minerals was reconstructed by means of the clustering algorithm and the clay clusters' structure judgment. The distributions and textures of the clay minerals of the digital core were reasonable. The clustering algorithm improved the digital core reconstruction and provided an alternative method for the simulation of different clay minerals in the digital cores.

Preparation of 13X from Waste Quartz and Photocatalytic Reaction of Methyl Orange on TiO2/ZSM-5, 13X and Y-Zeolite.

PubMed

Wang, Jia-Jie; Jing, You-Hai; Ouyang, Tong; Chang, Chang-Tang

2015-08-01

TiO2 photocatalytic reactions not only remove a variety of organic pollutants via complete mineralization, but also destroy the bacterial cell wall and cell membrane, thus playing an important bactericidal role. However, the post-filtration procedures to separate nanometer-levels of TiO2 and the gradual inactivity of photocatalyst during continuous use are defects that limit its application. In this case, we propose loading TiO2 on zeolite for easy separation and 13X is considered as a promising one. In our study, 13X-zeolite was prepared by a hydrothermal method and the source of Si was extracted from waste quartz sand. For comparison, commercial zeolite with different microporous and mesoporous diameters (ZSM-5 and Y-zeolites) were also used as TiO2 supports. The pore size of the three kinds of zeolites are as follows: Y-zeolite > 13X > ZSM-5. Different TiO2 loading content over ZSM-5, 13X and Y-zeolite were prepared by the sol-gel method. XRD, FTIR, BET, UV-vis, TGA and SEM were used for investigation of material characteristics. In addition, the efficiencies of mineralization and photodegradation were studied in this paper. The effects of the loading ratio of TiO2 over zeolites, initial pH, and concentration on photocatalytic performance are investigated. The relationship between best loading content of TiO2 and pore size of the zeolite was studied. The possible roles of the ZSM-5, 13X-zeolites and Y-zeolites support on the reactions and the possible mechanisms of effects were also explored. The best loading content of TiO2 over ZSM-5, 13X and Y-zeolite was found to be 50 wt%, 12.5 wt% and 7 wt%, respectively. The optimum pH condition is 3 with TiO2 over ZSM-5, 13X-zeolites and Y-zeolites. The results showed that the degradation and mineralization efficiency of 12.5 wt%GT13X (TiO2 over 13X) after 90 min irradiation reached 57.9% and 22.0%, which was better than that of 7 wt%GTYZ (TiO2 over Y-zeolites) while much lower than that of 50 wt%GTZ (TiO2 over ZSM-5). The materials were recycled four times while the degradation was remained at a higher level.

Killer clays! Natural antibacterial clay minerals

USGS Publications Warehouse

Williams, L.B.; Holland, M.; Eberl, D.D.; Brunet, T.; De Courrsou, L. B.

2004-01-01

The clay chemical properties that may be important in medicine were investigated. It was found that natural clay minerals can have striking and very specific effects on microbial populations. The effects can range from potentially enhanced microbial growth to complete sterilization. This paper presents evidence that natural clay minerals can be effective antimicrobial agents.

Sorption Kinetics Of Selected Heavy Metals Adsorption To Natural And Fe(III) Modified Zeolite Tuff Containing Clinoptilolite Mineral

NASA Astrophysics Data System (ADS)

Sirotiak, Maroš; Lipovský, Marek; Bartošová, Alica

2015-06-01

In the research described in this paper, studied was sorption capacity of natural and ferric modification of zeolite tuff containing mineral clinoptilolite from the Nižný Hrabovec deposit to remove potentially toxic metals (ionic forms of chromium, nickel, copper and aluminium) from their water solutions. We reported that the Fe (III) zeolite has an enhanced ability to sorption of Cu (II), and a slight improvement occurs in the case of Cr (VI) and Ni (II). On the other hand, the deterioration was observed in the case of Al (III) adsorption.

Immobilizing of catalyst using Bayah's natural zeolite to reduce the chemical oxygen demand (COD) and total organic carbon (TOC)

NASA Astrophysics Data System (ADS)

Jayanudin, Kustiningsih, Indar; Sari, Denni Kartika

2017-05-01

Indonesia is rich of natural minerals, many of which had not been widely used. One potential natural mineral is zeolite from Bayah Banten that can be used to support catalyst in the process of waste degradation. The purpose of this research is to characterize the Bayah's zeolite and to figure out the effectiveness of the zeolite as supporting agent to the Fe catalyst in the process of phenol degradation, with the main purposes are to reduce the Chemical Oxygen Demand (COD) and Total Organic Carbon (TOC). This research consists of three steps, activation of natural zeolite using 1M, 2M, and 3M NaOH solution, impregnation process with 0.025M, 0.05 M and 0.075M Fe(NO3)3.9H2O solution, and calcination at 500°C. Bayah's natural zeolite was characterize using Brauner-Emmet-Teller (BET) for its pore area, X-ray Fluorescence (XRF) for analyzing zeolite's component before and after activation process and after impregnation process, and Scanning Electron Microscope (SEM) for analyzing zeolite's morphology. The result showed that the highest pore area was 9Å, Fe metal from Fe(NO3)3.9H2O 0,075 M solution remained in zeolite pore was 7,73%, the reduction of COD and TOC was yielded at H2O2: phenol ratio of 1 : 6.

Effects of clay minerals on diethyl phthalate degradation in Fenton reactions.

PubMed

Chen, Ning; Fang, Guodong; Zhou, Dongmei; Gao, Juan

2016-12-01

Phthalate esters are a group of plasticizers, which are commonly detected in China's soils and surface water. Fenton reactions are naturally occurring and widely applied in the degradation of contaminants. However, limited research was considered the effects of clay minerals on contaminants degradation with OH oxidation. In this study, batch experiments were conducted to investigate the degradation of diethyl phthalate (DEP) in Fenton reactions in the presence of clay minerals, and the effects of clay type, Fe content in clay structure. The results showed the clay adsorption inhibited total degradation of DEP, and Fe content in clay structure played an important role in DEP degradation, including in solution and adsorbed in clay minerals. Clay minerals with less Fe content (<3%) quenched OH radical, while nontronite with Fe content 19.2% improved OH radical generation and accelerated DEP degradation in solution. The degradation of clay-adsorbed DEP was much slower than DEP in solution. Six main products of DEP degradation were identified, including monoethyl phthalate, phthalate acid, hydroxyl diethyl phthalate, etc. This study implied that phthalate ester's degradation would be much slower in natural water than expected in the presence of clay minerals. Copyright © 2016 Elsevier Ltd. All rights reserved.

Clay Mineral Structure Similar to Clays Observed in Mudstone on Mars

NASA Image and Video Library

2013-12-09

This schematic shows the atomic structure of the smallest units that make up the layers and interlayer region of clay minerals. This structure is similar to the clay mineral in drilled rock powder collected by NASA Curiosity Mars rover.

[Mechanism of tritium persistence in porous media like clay minerals].

PubMed

Wu, Dong-Jie; Wang, Jin-Sheng; Teng, Yan-Guo; Zhang, Ke-Ni

2011-03-01

To investigate the mechanisms of tritium persistence in clay minerals, three types of clay soils (montmorillonite, kaolinite and illite) and tritiated water were used in this study to conduct the tritium sorption tests and the other related tests. Firstly, the ingredients, metal elements and heat properties of clay minerals were studied with some instrumental analysis methods, such as ICP and TG. Secondly, with a specially designed fractionation and condensation experiment, the adsorbed water, the interlayer water and the structural water in the clay minerals separated from the tritium sorption tests were fractionated for investigating the tritium distributions in the different types of adsorptive waters. Thirdly, the location and configuration of tritium adsorbed into the structure of clay minerals were studied with infrared spectrometry (IR) tests. And finally, the forces and mechanisms for driving tritium into the clay minerals were analyzed on the basis of the isotope effect of tritium and the above tests. Following conclusions have been reached: (1) The main reason for tritium persistence in clay minerals is the entrance of tritium into the adsorbed water, the interlayer water and the structural water in clay minerals. The percentage of tritium distributed in these three types of adsorptive water are in the range of 13.65% - 38.71%, 0.32% - 5.96%, 1.28% - 4.37% of the total tritium used in the corresponding test, respectively. The percentages are different for different types of clay minerals. (2) Tritium adsorbed onto clay minerals are existed in the forms of the tritiated hydroxyl radical (OT) and the tritiated water molecule (HTO). Tritium mainly exists in tritiated water molecule for adsorbed water and interlayer water, and in tritiated hydroxyl radical for structural water. (3) The forces and effects driving tritium into the clay minerals may include molecular dispersion, electric charge sorption, isotope exchange and tritium isotope effect.

Recent advances in clay mineral-containing nanocomposite hydrogels.

PubMed

Zhao, Li Zhi; Zhou, Chun Hui; Wang, Jing; Tong, Dong Shen; Yu, Wei Hua; Wang, Hao

2015-12-28

Clay mineral-containing nanocomposite hydrogels have been proven to have exceptional composition, properties, and applications, and consequently have attracted a significant amount of research effort over the past few years. The objective of this paper is to summarize and evaluate scientific advances in clay mineral-containing nanocomposite hydrogels in terms of their specific preparation, formation mechanisms, properties, and applications, and to identify the prevailing challenges and future directions in the field. The state-of-the-art of existing technologies and insights into the exfoliation of layered clay minerals, in particular montmorillonite and LAPONITE®, are discussed first. The formation and structural characteristics of polymer/clay nanocomposite hydrogels made from in situ free radical polymerization, supramolecular assembly, and freezing-thawing cycles are then examined. Studies indicate that additional hydrogen bonding, electrostatic interactions, coordination bonds, hydrophobic interaction, and even covalent bonds could occur between the clay mineral nanoplatelets and polymer chains, thereby leading to the formation of unique three-dimensional networks. Accordingly, the hydrogels exhibit exceptional optical and mechanical properties, swelling-deswelling behavior, and stimuli-responsiveness, reflecting the remarkable effects of clay minerals. With the pivotal roles of clay minerals in clay mineral-containing nanocomposite hydrogels, the nanocomposite hydrogels possess great potential as superabsorbents, drug vehicles, tissue scaffolds, wound dressing, and biosensors. Future studies should lay emphasis on the formation mechanisms with in-depth insights into interfacial interactions, the tactical functionalization of clay minerals and polymers for desired properties, and expanding of their applications.

Program and Abstracts for Clay Minerals Society 28th Annual Meeting

NASA Technical Reports Server (NTRS)

1991-01-01

This volume contains abstracts that were accepted for presentation at the annual meeting. Some of the main topics covered include: (1) fundamental properties of minerals and methods of mineral analysis; (2) surface chemistry; (3) extraterrestrial clay minerals; (4) geothermometers and geochronometers; (5) smectite, vermiculite, illite, and related reactions; (6) soils and clays in environmental research; (7) kaolinite, halloysite, iron oxides, and mineral transformations; and (8) clays in lakes, basins, and reservoirs.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Caporuscio, Florie Andre; Norskog, Katherine Elizabeth; Maner, James

Over the past five years the Used Fuel Campaign has investigated Engineered Barrier Systems (EBS) at higher heat loads (up to 300°C) and pressure (150 bar). This past year experimental work was hindered due to a revamping of the hydrothermal lab. Regardless, two experiments were run this past year, EBS-18 and EBS-19. EBS-18 was run using Low Carbon Steel (LCS) and opalinus clay in addition to the bentonite and opalinus brine. Many of the past results were confirmed in EBS-18, such as the restriction of illite formation due to the bulk chemistry, pyrite degradation, and zeolite formation dependent on themore » bentonite and opalinus clay. The LCS show vast amounts of pit corrosion (over 100μm of corrosion in six weeks), leading a corrosion rate of 1083 μm/year. In addition, a mineral goethite, an iron-bearing hydroxide, formed in the pits of the LCS. Preliminary results from EBS-19 water chemistry are included but SEM imaging, micro probe and XRD are still needed for further results. Copper corrosion was investigated further and over 850 measurements were taken. It was concluded that pitting and pyrite degradation drastically increase the corrosion rate from 0.12 to 0.39 μm/day. However, the growth of a layer of the mineral chalcocite is thought to subdue the corrosion rate to 0.024 μm/day as observed in the EBS-13, a sixth month experiment. This document presents the findings of this past year.« less

Electron transfer and atom exchange between aqueous Fe(II) and structural Fe(III) in clays. Role in U and Hg(II) transformations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scherer, Michelle

2016-08-31

During this project, we investigated Fe electron transfer and atom exchange between aqueous Fe(II) and structural Fe(III) in clay minerals. We used selective chemical extractions, enriched Fe isotope tracer experiments, computational molecular modeling, and Mössbauer spectroscopy. Our findings indicate that structural Fe(III) in clay minerals is reduced by aqueous Fe(II) and that electron transfer occurs when Fe(II) is sorbed to either basal planes and edge OH-groups of clay mineral. Findings from highly enriched isotope experiments suggest that up to 30 % of the Fe atoms in the structure of some clay minerals exhanges with aqueous Fe(II). First principles calculations usingmore » a small polaron hopping approach suggest surprisingly fast electron mobility at room temperature in a nontronite clay mineral and are consistent with temperature dependent Mössbauer data Fast electron mobility suggests that electrons may be able to conduct through the mineral fast enough to enable exchange of Fe between the aqueous phase and clay mineral structure. over the time periods we observed. Our findings suggest that Fe in clay minerals is not as stable as previously thought.« less

Microbe-Clay Mineral Reactions and Characterization Techniques

NASA Astrophysics Data System (ADS)

Dong, H.; Zhang, G.; Ji, S.; Jaisi, D.; Kim, J.

2008-12-01

Clays and clay minerals are ubiquitous in soils, sediments, and sedimentary rocks. They play an important role in environmental processes such as nutrient cycling, plant growth, contaminant migration, organic matter maturation, and petroleum production. The changes in the oxidation state of the structural iron in clay minerals, in part, control their physical and chemical properties in natural environments, such as clay particle flocculation, dispersion, swelling, hydraulic conductivity, surface area, cation and anion exchange capacity, and reactivity towards organic and inorganic contaminants. The structural ferric iron [Fe(III)] in clay minerals can be reduced either chemically or biologically. Many different chemical reductants have been tried, but the most commonly used agent is dithionite. Biological reductants are bacteria, including dissimilatory iron reducing prokaryotes (DIRP) and sulfate-reducing bacteria (SRB). A wide variety of DIRP have been used to reduce ferric iron in clay minerals, including mesophilic, thermophilic, and hyperthermophilic prokaryotes. Multiple clay minerals have been used for microbial reduction studies, including smectite, nontronite (iron-rich smectite variety), illite, illite/smectite, chlorite, and their various mixtures. All these clay minerals are reducible by microorganisms under various conditions with smectite (nontronite) being the most reducible. The reduction extent and rate of ferric iron in clay minerals are measured by wet chemistry, and the reduced clay mineral products are typically characterized with chemical methods, X-ray diffraction, scanning and transmission electron microscopy, Mössbauer spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), UV-vis spectroscopy, and synchrotron-based techniques (such as EXAFS). Microbially reduced smectites (nontronites) have been found to be reactive in reducing a variety of organic and inorganic contaminants. Degradable organic contaminants include pesticides, solvents, explosives, and nitroaromatic and polychlorinated compounds. Inorganic contaminants include Cr(VI), U(VI), and Tc(VII). Despite significant efforts, our understanding of mechanisms of chemical and microbial reduction of ferric iron in clay minerals is still limited. While some studies have presented evidence for a solid-state reduction mechanism, others argue that the clay mineral structure dissolves when the extent of reduction is higher (greater than 30 percent). The electron transfer process is also dependent on the reducing agent. While chemical reduction of ferric iron appears to occur at the basal surfaces, bacteria appear to attack clay minerals at the edges.

Dynamic mechanical properties and anisotropy of synthetic shales with different clay minerals under confining pressure

NASA Astrophysics Data System (ADS)

Gong, Fei; Di, Bangrang; Wei, Jianxin; Ding, Pinbo; Shuai, Da

2018-03-01

The presence of clay minerals can alter the elastic behaviour of reservoir rocks significantly as the type of clay minerals, their volume and distribution, and their orientation control the shale's intrinsic anisotropic behaviours. Clay minerals are the most abundant materials in shale, and it has been proven extremely difficult to measure the elastic properties of natural shale by means of a single variable (in this case, the type of clay minerals), due to the influences of multiple factors, including water, TOC content and complex mineral compositions. We used quartz, clay (kaolinite, illite and smectite), carbonate and kerogen extract as the primary materials to construct synthetic shale with different clay minerals. Ultrasonic experiments were conducted to investigate the anisotropy of velocity and mechanical properties in dry synthetic and natural shale as a function of confining pressure. Velocities in synthetic shale are sensitive to the type of clay minerals, possibly due to the different structures of the clay minerals. The velocities increase with confining pressure and show higher rate of velocity increase at low pressures, and P-wave velocity is usually more sensitive than S-wave velocity to confining pressure according to our results. Similarly, the dynamic Young's modulus and Poisson's ratio increase with applied pressure, and the results also reveal that E11 is always larger than E33 and ν31 is smaller than ν12. Velocity and mechanical anisotropy decrease with increasing stress, and are sensitive to stress and the type of clay minerals. However, the changes of mechanical anisotropy with applied stress are larger compared with the velocity anisotropy, indicating that mechanical properties are more sensitive to the change of rock properties.

Hydrothermal alteration in research drill hole Y-3, Lower Geyser Basin, Yellowstone National Park, Wyoming

USGS Publications Warehouse

Bargar, Keith E.; Beeson, Melvin H.

1985-01-01

Y-3, a U.S. Geological Survey research diamond-drill hole in Lower Geyser Basin, Yellowstone National Park, Wyoming, reached a depth of 156.7 m. The recovered drill core consists of 42.2 m of surficial (mostly glacial) sediments and two rhyolite flows (Nez Perce Creek flow and an older, unnamed rhyolite flow) of the Central Plateau Member of the Pleistocene Plateau Rhyolite. Hydrothermal alteration is fairly extensive in most of the drill core. The surficial deposits are largely cemented by silica and zeolite minerals; and the two rhyolite flows are, in part, bleached by thermal water that deposited numerous hydrothermal minerals in cavities and fractures. Hydrothermal minerals containing sodium as a dominant cation (analcime, clinoptilolite, mordenite, Na-smectite, and aegirine) are more abundant than calcium-bearing minerals (calcite, fluorite, Ca-smectite, and pectolite) in the sedimentary section of the drill core. In the volcanic section of drill core Y-3, calcium-rich minerals (dachiardite, laumontite, yugawaralite, calcite, fluorite, Ca-smectite, pectolite, and truscottite) are predominant over sodium-bearing minerals (aegirine, mordenite, and Na-smectite). Hydrothermal minerals that contain significant amounts of potassium (alunite and lepidolite in the sediments and illitesmectite in the rhyolite flows) are found in the two drill-core intervals. Drill core y:.3 also contains hydrothermal silica minerals (opal, [3-cristobalite, chalcedony, and quartz), other clay minerals (allophane, halloysite, kaolinite, and chlorite), gypsum, pyrite, and hematite. The dominance of calcium-bearing hydrothermal minerals in the lower rhyolitic section of the y:.3 drill core appears to be due to loss of calcium, along with potassium, during adiabatic cooling of an ascending boiling water.

Clay minerals: Properties and applications to dermocosmetic products and perspectives of natural raw materials for therapeutic purposes-A review.

PubMed

Moraes, Jemima Daniela Dias; Bertolino, Silvana Raquel Alina; Cuffini, Silvia Lucia; Ducart, Diego Fernando; Bretzke, Pedro Eriberto; Leonardi, Gislaine Ricci

2017-12-20

Clay minerals are layered materials with a number of peculiar properties, which find many relevant applications in various industries. Since they are easily found everywhere, they are particularly attractive due to their economic viability. In the cosmetic industry, clay minerals are often used as excipients to stabilize emulsions or suspensions and to modify the rheological behavior of these systems. They also play an important role as adsorbents or absorbents, not only in cosmetics but also in other industries, such as pharmaceuticals. This reviewer believes that since this manuscript is presented as covering topical applications that include pharmaceuticals, some types of clay minerals should be considered as a potential material to be used as drug delivery systems. We review several applications of clay minerals to dermocosmetic products, relating them to the underlying properties of these materials and exemplifying with a number of clay minerals available in the market. We also discuss the use of clay minerals in topically-applied products for therapeutic purposes, specially for skin treatment and protection. Copyright © 2017 Elsevier B.V. All rights reserved.

Sorption of chlorophenols on microporous minerals: mechanism and influence of metal cations, solution pH, and humic acid.

PubMed

Yang, Hui; Hu, Yuanan; Cheng, Hefa

2016-10-01

Sorption of 2-chlorophenol (2-CP), 2,4-dichlorophenol (2,4-DCP), and 2,4,6-trichlorophenol (2,4,6-TCP) on a range of dealuminated zeolites were investigated to understand the mechanism of their sorption on microporous minerals, while the influence of common metal cations, solution pH, and humic acid was also studied. Sorption of chlorophenols was found to increase with the hydrophobicity of the sorbates and that of the microporous minerals, indicating the important role of hydrophobic interactions, while sorption was also stronger in the micropores of narrower sizes because of greater enhancement of the dispersion interactions. The presence of metal cations could enhance chlorophenol sorption due to the additional electrostatic attraction between metal cations exchanged into the mineral micropores and the chlorophenolates, and this effect was apparent on the mineral sorbent with a high density of surface cations (2.62 sites/nm(2)) in its micropores. Under circum-neutral or acidic conditions, neutral chlorophenol molecules adsorbed into the hydrophobic micropores through displacing the "loosely bound" water molecules, while their sorption was negligible under moderately alkaline conditions due to electrostatic repulsion between the negatively charged zeolite framework and anionic chlorophenolates. The influence of humic acid on sorption of chlorophenols on dealuminated Y zeolites suggests that its molecules did not block the micropores but created a secondary sorption sites by forming a "coating layer" on the external surface of the zeolites. These mechanistic insights could help better understand the interactions of ionizable chlorophenols and metal cations in mineral micropores and guide the selection and design of reusable microporous mineral sorbents for sorptive removal of chlorophenols from aqueous stream.

Epigenetic formation of amethyst-bearing geodes from Los Catalanes gemological district, Artigas, Uruguay, southern Paraná Magmatic Province

NASA Astrophysics Data System (ADS)

Duarte, L. C.; Hartmann, L. A.; Vasconcellos, M. A. Z.; Medeiros, J. T. N.; Theye, T.

2009-07-01

Giant geodes (up to 4 m long) in the massive central portions of altered basalt lavas from the Paraná Magmatic Province, southern Brazil and Uruguay, form a world-class source of amethyst and agate. Although the origin of the cavities has been ascribed to degassing of the lava at > 1150 °C, field evidence is conclusive that the giant amethyst-agate-filled geodes were formed by hydrothermal processes at low temperatures. We propose an epigenetic and hydrothermal model for the origin of giant geodes. This model includes hydrothermal brecciation during an early brittle stage and the late formation of the cavities (geodes). In the brittle stage an overpressured aqueous fluid affected the basalt in a P, T field delimited by temperatures between 100 and 150 °C and vapor pressures between 1.2 and 5.5 bar. The fluids were capable of lifting the roof and fracturing the host rock along new subhorizontal and subvertical fractures and breccias in the massive lava. The formation of these structures occurred at shallow depths, unit-by-unit. To open the cavities, dissolution of the now altered basalt to clay minerals is necessary. The process is closely linked to the highest alteration grade of mineralized lavas in Los Catalanes gemological district. Dissolution processes are observed in micrometer-scale in the studied basalts. The primary mineralogy, consisting of labradorite (± andesine) +augite + pigeonite + mesostasis (K-rich), was altered during the interaction of large volumes of hot aqueous fluid with the rock. The alteration of pigeonite and its replacement by smectite is observed around the cavities, followed by the precipitation of amorphous silica and microcrystalline quartz in clay-rich sites. Associated zeolites (heulandite + clinoptilolite) fill the newly formed cavities in progressive stages of hydrothermal alteration. Our data indicate that the temperatures were less than 200 °C and probably less than 150 °C; cavity formation occurred after alteration of the basalt to more than 60 vol.% clay minerals. We thus suggest that cavities related to geode formation are of epigenetic origin.

Sorption-desorption behavior of PCP on soil organic matter and clay minerals.

PubMed

Pu, Xunchi; Cutright, Teresa J

2006-08-01

Pentachlorophenol (PCP) contamination is a severe environmental problem due to its widespread occurrence, toxicity and recalcitrance. In order to gain a better understanding of the fate of PCP in soils, the role of the soil organic matter (SOM) and clay minerals in the PCP sorption-desorption was studied on two bulk field soils, two subsoils (i.e., SOM or clay-removed soil) and two artificial soils. The two field soils used were a silty loam from New Mexico (NM) containing 10% clay and a sandy-clay-loam from Colombia (CO) South America comprised of 18% clay minerals. The bulk CO soil containing kaolinite sorbed significantly less PCP than the NM soil. All soils depicted an apparent hysteresis during sorption. The CO bulk and subsoils desorbed 14-20% and 15-26% of the sorbed PCP respectively whereas the NM bulk and subsoils desorbed only 4-12% and 5-16%, respectively. Experiments conducted with pure clay and artificial soils indicated that the expandable clay minerals were key sorbent material. Additional studies to investigate the interaction between SOM and clay minerals are needed to fully understand sorptive phenomena.

Iodide uptake by negatively charged clay interlayers?

PubMed

Miller, Andrew; Kruichak, Jessica; Mills, Melissa; Wang, Yifeng

2015-09-01

Understanding iodide interactions with clay minerals is critical to quantifying risk associated with nuclear waste disposal. Current thought assumes that iodide does not interact directly with clay minerals due to electrical repulsion between the iodide and the negatively charged clay layers. However, a growing body of work indicates a weak interaction between iodide and clays. The goal of this contribution is to report a conceptual model for iodide interaction with clays by considering clay mineral structures and emergent behaviors of chemical species in confined spaces. To approach the problem, a suite of clay minerals was used with varying degrees of isomorphic substitution, chemical composition, and mineral structure. Iodide uptake experiments were completed with each of these minerals in a range of swamping electrolyte identities (NaCl, NaBr, KCl) and concentrations. Iodide uptake behaviors form distinct trends with cation exchange capacity and mineral structure. These trends change substantially with electrolyte composition and concentration, but do not appear to be affected by solution pH. The experimental results suggest that iodide may directly interact with clays by forming ion-pairs (e.g., NaI(aq)) which may concentrate within the interlayer space as well as the thin areas surrounding the clay particle where water behavior is more structured relative to bulk water. Ion pairing and iodide concentration in these zones is probably driven by the reduced dielectric constant of water in confined space and by the relatively high polarizability of the iodide species. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effect of Annealing Temperature on Broad Luminescence of Silver-Exchanged Zeolites Y and A

NASA Astrophysics Data System (ADS)

Gui, Sa Chu Rong; Lin, H.; Bao, W.; Wang, W.

2018-05-01

The annealing temperature dependence of luminescence properties of silver (Ag)-exchanged zeolites Y and A was studied. It was found that the absorbance and excitation/emission bands are strongly affected by the thermal treatments. With increase in annealing temperature, the absorbance of Ag in zeolite Y increases at first and then decreases. However, the position of the excitation/emission band in zeolite Y was found to be insensitive to the annealing temperature. In contrast, the excitation/emission bands in zeolite A are particularly sensitive to the annealing temperature. The difference of such temperature dependence in zeolites Y and A may be due to the different microporous structure of the two minerals. Moreover, the fact that this dependence is not observed in Ag-exchanged zeolite Y is likely to be due to the difficulty in dehydration of zeolite Y in air or due to the weak Ag+-Ag+ interaction in zeolite Y.

Mineral resource of the Month: Clay

USGS Publications Warehouse

Virta, Robert L.

2010-01-01

Clays were one of the first mineral commodities used by people. Clay pottery has been found in archeological sites that are 12,000 years old, and clay figurines have been found in sites that are even older.

Clay-mineral suites, sources, and inferred dispersal routes: Southern California continental shelf

USGS Publications Warehouse

Hein, J.R.; Dowling, J.S.; Schuetze, A.; Lee, H.J.

2003-01-01

Clay mineralogy is useful in determining the distribution, sources, and dispersal routes of fine-grained sediments. In addition, clay minerals, especially smectite, may control the degree to which contaminants are adsorbed by the sediment. We analyzed 250 shelf sediment samples, 24 river-suspended-sediment samples, and 12 river-bed samples for clay-mineral contents in the Southern California Borderland from Point Conception to the Mexico border. In addition, six samples were analyzed from the Palos Verdes Headland in order to characterize the clay minerals contributed to the offshore from that point source. The <2 ??m-size fraction was isolated, Mg-saturated, and glycolated before analysis by X-ray diffraction. Semi-quantitative percentages of smectite, illite, and kaolinite plus chlorite were calculated using peak areas and standard weighting factors. Most fine-grained sediment is supplied to the shelf by rivers during major winter storms, especially during El Nin??o years. The largest sediment fluxes to the region are from the Santa Ynez and Santa Clara Rivers, which drain the Transverse Ranges. The mean clay-mineral suite for the entire shelf sediment data set (26% smectite, 50% illite, 24% kaolinite+chlorite) is closely comparable to that for the mean of all the rivers (31% smectite, 49% illite, 20% kaolinite+chlorite), indicating that the main source of shelf fine-grained sediments is the adjacent rivers. However, regional variations do exist and the shelf is divided into four provinces with characteristic clay-mineral suites. The means of the clay-mineral suites of the two southernmost provinces are within analytical error of the mineral suites of adjacent rivers. The next province to the north includes Santa Monica Bay and has a suite of clay minerals derived from mixing of fine-grained sediments from several sources, both from the north and south. The northernmost province clay-mineral suite matches moderately well that of the adjacent rivers, but does indicate some mixing from sources in adjacent provinces.

Chemical models for martian weathering profiles: Insights into formation of layered phyllosilicate and sulfate deposits

NASA Astrophysics Data System (ADS)

Zolotov, Mikhail Yu.; Mironenko, Mikhail V.

2016-09-01

Numerical chemical models for water-basalt interaction have been used to constrain the formation of stratified mineralogical sequences of Noachian clay-bearing rocks exposed in the Mawrth Vallis region and in other places on cratered martian highlands. The numerical approaches are based on calculations of water-rock type chemical equilibria and models which include rates of mineral dissolution. Results show that the observed clay-bearing sequences could have formed through downward percolation and neutralization of acidic H2SO4-HCl solutions. A formation of weathering profiles by slightly acidic fluids equilibrated with current atmospheric CO2 requires large volumes of water and is inconsistent with observations. Weathering by solutions equilibrated with putative dense CO2 atmospheres leads to consumption of CO2 to abundant carbonates which are not observed in clay stratigraphies. Weathering by H2SO4-HCl solutions leads to formation of amorphous silica, Al-rich clays, ferric oxides/oxyhydroxides, and minor titanium oxide and alunite at the top of weathering profiles. Mg-Fe phyllosilicates, Ca sulfates, zeolites, and minor carbonates precipitate from neutral and alkaline solutions at depth. Acidic weathering causes leaching of Na, Mg, and Ca from upper layers and accumulation of Mg-Na-Ca sulfate-chloride solutions at depth. Neutral MgSO4 type solutions dominate in middle parts of weathering profiles and could occur in deeper layers owing to incomplete alteration of Ca minerals and a limited trapping of Ca to sulfates. Although salts are not abundant in the Noachian geological formations, the results suggest the formation of Noachian salty solutions and their accumulation at depth. A partial freezing and migration of alteration solutions could have separated sulfate-rich compositions from low-temperature chloride brines and contributed to the observed diversity of salt deposits. A Hesperian remobilization and release of subsurface MgSO4 type solutions into newly-formed depressions could account for formation of some massive layered sulfate deposits through freezing or evaporation. This scenario explains the observed deficiency of salts in Noachian formations, a paucity of Hesperian phyllosilicates, and the occurrence of sulfate deposits in Valles Marineris troughs, chaotic terrains, and some craters of the Hesperian age.

Clay mineral formation under oxidized conditions and implications for paleoenvironments and organic preservation on Mars

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gainey, Seth R.; Hausrath, Elisabeth M.; Adcock, Christopher T.

Clay mineral-bearing locations have been targeted for martian exploration as potentially habitable environments and as possible repositories for the preservation of organic matter. Although organic matter has been detected at Gale Crater, Mars, its concentrations are lower than expected from meteoritic and indigenous igneous and hydrothermal reduced carbon. We conducted synthesis experiments motivated by the hypothesis that some clay mineral formation may have occurred under oxidized conditions conducive to the destruction of organics. Previous work has suggested that anoxic and/or reducing conditions are needed to synthesize the Fe-rich clay mineral nontronite at low temperatures. In contrast, our experiments demonstrated themore » rapid formation of Fe-rich clay minerals of variable crystallinity from aqueous Fe3+ with small amounts of aqueous Mg2+. Our results suggest that Fe-rich clay minerals such as nontronite can form rapidly under oxidized conditions, which could help explain low concentrations of organics within some smectite-containing rocks or sediments on Mars.« less

Clay mineral formation under oxidized conditions and implications for paleoenvironments and organic preservation on Mars.

PubMed

Gainey, Seth R; Hausrath, Elisabeth M; Adcock, Christopher T; Tschauner, Oliver; Hurowitz, Joel A; Ehlmann, Bethany L; Xiao, Yuming; Bartlett, Courtney L

2017-11-01

Clay mineral-bearing locations have been targeted for martian exploration as potentially habitable environments and as possible repositories for the preservation of organic matter. Although organic matter has been detected at Gale Crater, Mars, its concentrations are lower than expected from meteoritic and indigenous igneous and hydrothermal reduced carbon. We conducted synthesis experiments motivated by the hypothesis that some clay mineral formation may have occurred under oxidized conditions conducive to the destruction of organics. Previous work has suggested that anoxic and/or reducing conditions are needed to synthesize the Fe-rich clay mineral nontronite at low temperatures. In contrast, our experiments demonstrated the rapid formation of Fe-rich clay minerals of variable crystallinity from aqueous Fe 3+ with small amounts of aqueous Mg 2+ . Our results suggest that Fe-rich clay minerals such as nontronite can form rapidly under oxidized conditions, which could help explain low concentrations of organics within some smectite-containing rocks or sediments on Mars.

Microbial reduction of structural iron in interstratified illite-smectite minerals by a sulfate-reducing bacterium

USGS Publications Warehouse

Liu, D.; Dong, H.; Bishop, M.E.; Zhang, Jiahua; Wang, Hongfang; Xie, S.; Wang, Shaoming; Huang, L.; Eberl, D.D.

2012-01-01

Clay minerals are ubiquitous in soils, sediments, and sedimentary rocks and could coexist with sulfate-reducing bacteria (SRB) in anoxic environments, however, the interactions of clay minerals and SRB are not well understood. The objective of this study was to understand the reduction rate and capacity of structural Fe(III) in dioctahedral clay minerals by a mesophilic SRB, Desulfovibrio vulgaris and the potential role in catalyzing smectite illitization. Bioreduction experiments were performed in batch systems, where four different clay minerals (nontronite NAu-2, mixed-layer illite-smectite RAr-1 and ISCz-1, and illite IMt-1) were exposed to D. vulgaris in a non-growth medium with and without anthraquinone-2,6-disulfonate (AQDS) and sulfate. Our results demonstrated that D. vulgaris was able to reduce structural Fe(III) in these clay minerals, and AQDS enhanced the reduction rate and extent. In the presence of AQDS, sulfate had little effect on Fe(III) bioreduction. In the absence of AQDS, sulfate increased the reduction rate and capacity, suggesting that sulfide produced during sulfate reduction reacted with the phyllosilicate Fe(III). The extent of bioreduction of structural Fe(III) in the clay minerals was positively correlated with the percentage of smectite and mineral surface area of these minerals. X-ray diffraction, and scanning and transmission electron microscopy results confirmed formation of illite after bioreduction. These data collectively showed that D. vulgaris could promote smectite illitization through reduction of structural Fe(III) in clay minerals. ?? 2011 Blackwell Publishing Ltd.

Clay Minerals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mueller, Karl T.; Sanders, Rebecca L.; Washton, Nancy M.

2014-03-14

Clay minerals are important components of the environment and are involved or implicated in processes such as the uptake of pollutants and the release of nutrients and as potential platforms for a number of chemical reactions. Owing to their small particle sizes (typically, on the order of microns or smaller) and mixing with a variety of other minerals and soil components, advanced characterization methods are needed to study their structures, dynamics, and reactivities. In this article, we describe the use of solid-state NMR methods to characterize the structures and chemistries of clay minerals. Early one-pulse magic-angle spinning (MAS) NMR studiesmore » of 27Al and 29Si have now been enhanced and extended with new studies utilizing advanced methodologies (such as Multiple Quantum MAS) as well as studies of less-sensitive nuclei. In additional work, the issue of reactivity of clay minerals has been addressed, including studies of reactive surface area in the environment. Utilizations of NMR-sensitive nuclides within the clay minerals themselves, and in molecules that react with specific sites on the clay mineral surfaces, have aided in understanding the reactivity of these complex aluminosilicate systems.« less

Crude oil polycyclic aromatic hydrocarbons removal via clay-microbe-oil interactions: Effect of acid activated clay minerals.

PubMed

Ugochukwu, Uzochukwu C; Fialips, Claire I

2017-07-01

Acid treatment of clay minerals is known to modify their properties such as increase their surface area and surface acidity, making them suitable as catalysts in many chemical processes. However, the role of these surface properties during biodegradation processes of polycyclic aromatic hydrocarbons (PAHs) is only known for mild acid (0.5 M Hydrochloric acid) treated clays. Four different clay minerals were used for this study: a montmorillonite, a saponite, a palygorskite and a kaolinite. They were treated with 3 M hydrochloric acid to produce acid activated clay minerals. The role of the acid activated montmorillonite, saponite, palygorskite and kaolinite in comparison with the unmodified clay minerals in the removal of PAHs during biodegradation was investigated in microcosm experiments. The microcosm experiments contained micro-organisms, oil, and clays in aqueous medium with a hydrocarbon degrading microorganism community predominantly composed of Alcanivorax spp. Obtained results indicated that acid activated clays and unmodified kaolinite did not enhance the biodegradation of the PAHs whereas unmodified montmorillonite, palygorskite and saponite enhanced their biodegradation. In addition, unmodified palygorskite adsorbed the PAHs significantly due to its unique channel structure. Copyright © 2017 Elsevier Ltd. All rights reserved.

Surveying Clay Mineral Diversity in the Murray Formation, Gale Crater, Mars

NASA Technical Reports Server (NTRS)

Bristow, T. F.; Blake, D. F.; Vaniman, D. T.; Chipera, S. J.; Rampe, E. B.; Grotzinger, J. P.; McAdam, A. C.; Ming, D. W.; Morrison, S. M.; Yen, A. S.;

Sm-Nd dating of Fig Tree clay minerals of the Barberton greenstone belt, South Africa.

PubMed

Toulkeridis, T; Goldstein, S L; Clauer, N; Kroner, A; Lowe, D R

1994-03-01

Sm-Nd isotopic data from carbonate-derived clay minerals of the 3.22-3.25 Ga Fig Tree Group, Barberton greenstone belt, South Africa, form a linear array corresponding to an age of 3102 +/- 64 Ma, making these minerals the oldest dated clays on Earth. The obtained age is 120-160 m.y. younger than the depositional age determined by zircon geochronology. Nd model ages for the clays range from approximately 3.39 to 3.44 Ga and almost cover the age variation of the Barberton greenstone belt rocks, consistent with independent evidence that the clay minerals are derived from material of the belt. The combined isotopic and mineralogical data provide evidence for a cryptic thermal overprint in the sediments of the belt. However, the highest temperature reached by the samples since the time of clay-mineral formation was <300 degrees C, lower than virtually any known early Archean supracrustal sequence.

Sm-Nd dating of Fig Tree clay minerals of the Barberton greenstone belt, South Africa

NASA Technical Reports Server (NTRS)

Toulkeridis, T.; Goldstein, S. L.; Clauer, N.; Kroner, A.; Lowe, D. R.

1994-01-01

Sm-Nd isotopic data from carbonate-derived clay minerals of the 3.22-3.25 Ga Fig Tree Group, Barberton greenstone belt, South Africa, form a linear array corresponding to an age of 3102 +/- 64 Ma, making these minerals the oldest dated clays on Earth. The obtained age is 120-160 m.y. younger than the depositional age determined by zircon geochronology. Nd model ages for the clays range from approximately 3.39 to 3.44 Ga and almost cover the age variation of the Barberton greenstone belt rocks, consistent with independent evidence that the clay minerals are derived from material of the belt. The combined isotopic and mineralogical data provide evidence for a cryptic thermal overprint in the sediments of the belt. However, the highest temperature reached by the samples since the time of clay-mineral formation was <300 degrees C, lower than virtually any known early Archean supracrustal sequence.

Clay-mineral assemblages from some levels of K-118 drill core of Maha Sarakham evaporites, northeastern Thailand

NASA Astrophysics Data System (ADS)

Suwanich, Parkorn

Clay-mineral assemblages in Middle Clastic, Middle Salt, Lower Clastic, Potash Zone, and Lower Salt, totalling 13 samples from K-118 drill core, in the Maha Sarakham Formation, Khorat Basin, northeastern Thailand were studied. The clay-size particles were separated from the water-soluble salt by water leaching. Then the samples were leached again in the EDTA solution and separated into clay-size particles by using the timing sedimentation. The EDTA-clay residues were divided and analyzed by using the XRD and XRF method. The XRD peaks show that the major-clay minerals are chlorite, illite, and mixed-layer corrensite including traces of rectorite? and paragonite? The other clay-size particles are quartz and potassium feldspar. The XRF results indicate Mg-rich values and moderate MgAl atom ratio values in those clay minerals. The variable Fe, Na, and K contents in the clay-mineral assemblages can explain the environment of deposition compared to the positions of the samples from the core. Hypothetically, mineralogy and the chemistry of the residual assemblages strongly indicate that severe alteration and Mg-enrichment of normal clay detritus occurred in the evaporite environment through brine-sediment interaction. The various Mg-enrichment varies along the various members reflecting whether sedimentation is near or far from the hypersaline brine.

Adsorption of Dissolved Gases (CH4, CO2, H2, Noble Gases) by Water-Saturated Smectite Clay Minerals

NASA Astrophysics Data System (ADS)

Bourg, I. C.; Gadikota, G.; Dazas, B.

2016-12-01

Adsorption of dissolved gases by water-saturated clay minerals plays important roles in a range of fields. For example, gas adsorption in on clay minerals may significantly impact the formation of CH4 hydrates in fine-grained sediments, the behavior of CH4 in shale, CO2 leakage across caprocks of geologic CO2 sequestration sites, H2 leakage across engineered clay barriers of high-level radioactive waste repositories, and noble gas geochemistry reconstructions of hydrocarbon migration in the subsurface. Despite its importance, the adsorption of gases on clay minerals remains poorly understood. For example, some studies have suggested that clay surfaces promote the formation of CH4 hydrates, whereas others indicate that clay surfaces inhibit the formation of CH4 hydrates. Here, we present molecular dynamics (MD) simulations of the adsorption of a range of gases (CH4, CO2, H2, noble gases) on clay mineral surfaces. Our results indicate that the affinity of dissolved gases for clay mineral surfaces has a non-monotone dependence on the hydrated radius of the gas molecules. This non-monotone dependence arises from a combination of two effects: the polar nature of certain gas molecules (in particular, CO2) and the templating of interfacial water structure by the clay basal surface, which results in the presence of interfacial water "cages" of optimal size for intermediate-size gas molecules (such as Ne or Ar).

The influence of shale depositional fabric on the kinetics of hydrocarbon generation through control of mineral surface contact area on clay catalysis

NASA Astrophysics Data System (ADS)

Rahman, Habibur M.; Kennedy, Martin; Löhr, Stefan; Dewhurst, David N.; Sherwood, Neil; Yang, Shengyu; Horsfield, Brian

2018-01-01

Accurately assessing the temperature and hence the depth and timing of hydrocarbon generation is a critical step in the characterization of a petroleum system. Clay catalysis is a potentially significant modifier of hydrocarbon generation temperature, but experimental studies of clay catalysis show inconsistent or contradictory results. This study tests the hypothesis that source rock fabric itself is an influence on clay mineral catalysis as it controls the extent to which organic matter and clay minerals are physically associated. Two endmember clay-organic fabrics distinguish the source rocks studied: (1) a particulate fabric where organic matter is present as discrete, >5 μm particles and (2) a nanocomposite fabric in which amorphous organic matter is associated with clay mineral surfaces at sub-micron scale. High-resolution electron imaging and bulk geochemical characterisation confirm that samples of the Miocene Monterey Formation (California) are representative of the nanocomposite source rock endmember, whereas samples from the Permian Stuart Range Formation (South Australia) represent the particulate source rock endmember. Kinetic experiments are performed on paired whole rock and kerogen isolate samples from these two formations using open system, non-isothermal pyrolysis at three different heating rates (0.7, 2 and 5 K/min) to determine the effects of the different shale fabrics on hydrocarbon generation kinetics. Extrapolation to a modelled geological heating rate shows a 20 °C reduction in the onset temperature of hydrocarbon generation in Monterey Formation whole rock samples relative to paired kerogen isolates. This result is consistent with the Monterey Formations's nanocomposite fabric where clay catalysis can proceed because reactive clay minerals are intimately associated with organic matter. By contrast, there is no significant difference in the modelled hydrocarbon generation temperature of paired whole rock and kerogen isolates from the Stuart Range Formation. This is consistent with its particulate fabric, where relatively large, discrete organic particles have limited contact with the mineral matrix and the clay minerals are mainly diagenetic and physically segregated within pores. While heating rate may have a control on mineral matrix effects, this result shows that the extent to which organic matter and clay minerals are physically associated could have a significant effect on the timing of hydrocarbon generation, and is a function of the depositional environment and detrital vs diagenetic origin of clay minerals in source rocks.

Clays and clay minerals in Bikaner: Sources, environment pollution and management

NASA Astrophysics Data System (ADS)

Gayatri, Sharma; Anu, Sharma

2016-05-01

Environmental pollution can also be caused by minerals which include natural as well as human activities. Rapid urbanization, consumerist life style, anthropogenic deeds are increasing environmental pollution day by day. Fluctuation in our ecosystem or polluted environment leads to many diseases and shows adverse effects on living organisms. The main aim of this paper is to highlight the environmental pollution from clays and clay minerals and their mitigation..

Adsorption and Desorption of Cesium in Clay Minerals: Effects of Natural Organic Matter and pH

NASA Astrophysics Data System (ADS)

Yoon, Hongkyu; Ilgen, Anastasia; Mills, Melissa; Lee, Moo; Seol, Jeung Gun; Cho, Nam Chan; Kang, Hyungyu

2017-04-01

Cesium (Cs) released into the environment (e.g., Fukushima accident) poses significant environmental concerns and remediation challenges. A majority of Cs in the environment have remained within the surface soils due to the strong adsorption affinity of Cs towards clay minerals. Different clay minerals have different bonding sites, resulting in various adsorption mechanisms at nanometer scale. For example, the illite commonly has a basal spacing of 1.0 nm, but becomes wider to 1.4 nm once other cations exchange with K in the interlayer site. Cs adsorbs into these expanded wedged zone strongly, which can control its mobility in the environment. In addition, natural organic matter (NOM) in the surface soils can interact with clay minerals, which can modify the mechanisms of Cs adsorption on the clay minerals by blocking specific adsorption sites and/or providing Cs adsorption sites on NOM surface. In this work, three representative clay minerals (illite, vermiculite, montmorillonite) and humic acid (HA) are used to systematically investigate the adsorption and desorption behavior of Cs. We performed batch adsorption experiments over a range of Cs concentrations on three clay minerals with and without HA, followed by sequential desorption batch testing. We tested desorption efficiency as a function of initial adsorbed Cs concentration, HA content, sodium concentration, and pH. The sequential extraction results are compared to the structural changes in clay minerals, measured using extended X-ray absorption fine structure spectroscopy (EXAFS) and aberration-corrected (scanning) transmission electron microscopy (TEM) - energy dispersive X-ray spectroscopy (EDX). Hence, this work aims to identify the mechanisms of Cs fixation at the nanometer (or atomic-) scale as a function of the clay mineral properties (e.g. expandability, permanent surface charge) and varying organic matter content at different pH values and to enhance our atomic-scale mechanistic understanding of the clay mineral interactions with cesium in the presence of NOM. The expandability of clay minerals and effect of HA addition on Cs adsorption and desorption are highlighted to address the efficiency of Cs removal schemes from contaminated soils. Sandia National Laboratories is a multi-mission laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Clay Mineral Crystal Structure Tied to Composition

NASA Image and Video Library

2016-12-13

This diagram illustrates how the dimensions of clay minerals' crystal structure are affected by which ions are present in the composition of the mineral. Different clay minerals were identified this way at two sites in Mars' Gale Crater: "Murray Buttes" and "Yellowknife Bay." In otherwise identical clay minerals, a composition that includes aluminum and ferric iron ions (red dots) results in slightly smaller crystalline unit cells than one that instead includes magnesium and ferrous iron ions (green dots). Ferric iron is more highly oxidized than ferrous iron. Crystalline cell units are the basic repeating building blocks that define minerals. X-ray diffraction analysis, a capability of the Chemistry and Mineralogy (CheMin) instrument on NASA's Curiosity Mars rover, identifies minerals from their crystalline structure. http://photojournal.jpl.nasa.gov/catalog/PIA21148

Microbial reduction of structural iron in interstratified illite-smectite minerals by a sulfate-reducing bacterium.

PubMed

Liu, D; Dong, H; Bishop, M E; Zhang, J; Wang, H; Xie, S; Wang, S; Huang, L; Eberl, D D

2012-03-01

Clay minerals are ubiquitous in soils, sediments, and sedimentary rocks and could coexist with sulfate-reducing bacteria (SRB) in anoxic environments, however, the interactions of clay minerals and SRB are not well understood. The objective of this study was to understand the reduction rate and capacity of structural Fe(III) in dioctahedral clay minerals by a mesophilic SRB, Desulfovibrio vulgaris and the potential role in catalyzing smectite illitization. Bioreduction experiments were performed in batch systems, where four different clay minerals (nontronite NAu-2, mixed-layer illite-smectite RAr-1 and ISCz-1, and illite IMt-1) were exposed to D. vulgaris in a non-growth medium with and without anthraquinone-2,6-disulfonate (AQDS) and sulfate. Our results demonstrated that D. vulgaris was able to reduce structural Fe(III) in these clay minerals, and AQDS enhanced the reduction rate and extent. In the presence of AQDS, sulfate had little effect on Fe(III) bioreduction. In the absence of AQDS, sulfate increased the reduction rate and capacity, suggesting that sulfide produced during sulfate reduction reacted with the phyllosilicate Fe(III). The extent of bioreduction of structural Fe(III) in the clay minerals was positively correlated with the percentage of smectite and mineral surface area of these minerals. X-ray diffraction, and scanning and transmission electron microscopy results confirmed formation of illite after bioreduction. These data collectively showed that D. vulgaris could promote smectite illitization through reduction of structural Fe(III) in clay minerals. © 2011 Blackwell Publishing Ltd.

[Research on characteristics of soil clay mineral evolution in paddy field and dry land by XRD spectrum].

PubMed

Zhang, Zhi-dan; Li, Qiao; Luo, Xiang-li; Jiang, Hai-chao; Zheng, Qing-fu; Zhao, Lan-po; Wang, Ji-hong

2014-08-01

The present paper took the typical saline-alkali soil in Jilin province as study object, and determinated the soil clay mineral composition characteristics of soil in paddy field and dry land. Then XRD spectrum was used to analyze the evolutionary mechanism of clay mineral in the two kinds of soil. The results showed that the physical and chemical properties of soil in paddy field were better than those in dry land, and paddy field would promote the weathering of mineral particles in saline-alkali soil and enhance the silt content. Paddy field soil showed a strong potassium-removal process, with a higher degree of clay mineral hydration and lower degree of illite crystallinity. Analysis of XRD spectrum showed that the clay mineral composition was similar in two kinds of soil, while the intensity and position of diffraction peak showed difference. The evolution process of clay mineral in dry land was S/I mixture-->vermiculite, while in paddy field it was S/I mixture-->vermiculite-->kaolinite. One kind of hydroxylated 'chlorite' mineral would appear in saline-alkali soil in long-term cultivated paddy field. Taking into account that the physical and chemical properties of soil in paddy field were better then those in dry land, we could know that paddy field could help much improve soil structure, cultivate high-fertility soil and improve saline-alkali soil. This paper used XRD spectrum to determine the characteristics of clay minerals comprehensively, and analyzed two'kinds of land use comparatively, and was a new perspective of soil minerals study.

Microbial Impacts on Clay Mineral Transformation and Reactivity

NASA Astrophysics Data System (ADS)

Dong, H.; Jaisi, D.; Fredrickson, J.; Plymale, A.

2006-05-01

Clays and clay minerals are ubiquitous in soils, sedimentary rocks, and pelagic oozes. They play important roles in environmental processes such as nutrient cycling, plant growth, contaminant migration, organic matter maturation, and petroleum production. Iron is a major constituent in clay minerals, and its mobility and stability in different environmental processes is, in part, controlled by the oxidation state. Recent studies have shown that biological reduction of structural Fe(III) in clay minerals can change the physical and chemical properties of clay minerals, such as swelling, cation exchange and fixation capacity, specific surface area, color, and magnetic exchange interactions. As a result of biological reduction of Fe(III), clay minerals also undergo mineral transformations, such as dissolution of smectite and precipitation of illite, siderite and vivianite. These chemical, structural and mineralogical changes of clay minerals have a profound effect on clay mineral reactivity, such as their reactivity with organic and inorganic (i.e., heavy metals and radionuclides) contaminants. Our latest data show that biologically reduced nontronite (a smectite variety) is much more effective in reducing soluble and mobile Tc(VII) to Tc(IV) than unreduced nontronite. The reduced Tc(IV) is insoluble in groundwater and soil and thus is immobile. Biologically reduced nontronite can be prepared by microbially reducing Fe(III) in nontronite by Shewanella putrefaciens in the absence of oxygen. Approximately 30% of structurally Fe(III) can be reduced in this manner. Biogenic Fe(II) can then serve as an electron donor to reduce Tc(VII). Nearly all Fe(II) is available to reduce Tc(VII), with the rate of reduction (typically within weeks) possibly depending on the speciation of Fe(II) (surface sorbed Fe(II) vs. structural Fe(II)). Further investigations are underway to further assess the reversibility of Tc reduction upon exposure to oxygen and to elucidate Tc reduction kinetics. These preliminary results have important implications for in-situ bioremediation efforts, where either chemically or biologically reduced clay minerals can be introduced into a contaminant site for removing heavy metals and radionuclides in groundwater aquifers.

La roca magica: Uses of natural zeolites in agriculture and industry

PubMed Central

Mumpton, Frederick A.

1999-01-01

For nearly 200 years since their discovery in 1756, geologists considered the zeolite minerals to occur as fairly large crystals in the vugs and cavities of basalts and other traprock formations. Here, they were prized by mineral collectors, but their small abundance and polymineralic nature defied commercial exploitation. As the synthetic zeolite (molecular sieve) business began to take hold in the late 1950s, huge beds of zeolite-rich sediments, formed by the alteration of volcanic ash (glass) in lake and marine waters, were discovered in the western United States and elsewhere in the world. These beds were found to contain as much as 95% of a single zeolite; they were generally flat-lying and easily mined by surface methods. The properties of these low-cost natural materials mimicked those of many of their synthetic counterparts, and considerable effort has made since that time to develop applications for them based on their unique adsorption, cation-exchange, dehydration–rehydration, and catalytic properties. Natural zeolites (i.e., those found in volcanogenic sedimentary rocks) have been and are being used as building stone, as lightweight aggregate and pozzolans in cements and concretes, as filler in paper, in the take-up of Cs and Sr from nuclear waste and fallout, as soil amendments in agronomy and horticulture, in the removal of ammonia from municipal, industrial, and agricultural waste and drinking waters, as energy exchangers in solar refrigerators, as dietary supplements in animal diets, as consumer deodorizers, in pet litters, in taking up ammonia from animal manures, and as ammonia filters in kidney-dialysis units. From their use in construction during Roman times, to their role as hydroponic (zeoponic) substrate for growing plants on space missions, to their recent success in the healing of cuts and wounds, natural zeolites are now considered to be full-fledged mineral commodities, the use of which promise to expand even more in the future. PMID:10097058

La roca magica: uses of natural zeolites in agriculture and industry.

PubMed

Mumpton, F A

1999-03-30

For nearly 200 years since their discovery in 1756, geologists considered the zeolite minerals to occur as fairly large crystals in the vugs and cavities of basalts and other traprock formations. Here, they were prized by mineral collectors, but their small abundance and polymineralic nature defied commercial exploitation. As the synthetic zeolite (molecular sieve) business began to take hold in the late 1950s, huge beds of zeolite-rich sediments, formed by the alteration of volcanic ash (glass) in lake and marine waters, were discovered in the western United States and elsewhere in the world. These beds were found to contain as much as 95% of a single zeolite; they were generally flat-lying and easily mined by surface methods. The properties of these low-cost natural materials mimicked those of many of their synthetic counterparts, and considerable effort has made since that time to develop applications for them based on their unique adsorption, cation-exchange, dehydration-rehydration, and catalytic properties. Natural zeolites (i.e., those found in volcanogenic sedimentary rocks) have been and are being used as building stone, as lightweight aggregate and pozzolans in cements and concretes, as filler in paper, in the take-up of Cs and Sr from nuclear waste and fallout, as soil amendments in agronomy and horticulture, in the removal of ammonia from municipal, industrial, and agricultural waste and drinking waters, as energy exchangers in solar refrigerators, as dietary supplements in animal diets, as consumer deodorizers, in pet litters, in taking up ammonia from animal manures, and as ammonia filters in kidney-dialysis units. From their use in construction during Roman times, to their role as hydroponic (zeoponic) substrate for growing plants on space missions, to their recent success in the healing of cuts and wounds, natural zeolites are now considered to be full-fledged mineral commodities, the use of which promise to expand even more in the future.

Global distribution of clay-size minerals on land surface for biogeochemical and climatological studies

PubMed Central

Ito, Akihiko; Wagai, Rota

2017-01-01

Clay-size minerals play important roles in terrestrial biogeochemistry and atmospheric physics, but their data have been only partially compiled at global scale. We present a global dataset of clay-size minerals in the topsoil and subsoil at different spatial resolutions. The data of soil clay and its mineralogical composition were gathered through a literature survey and aggregated by soil orders of the Soil Taxonomy for each of the ten groups: gibbsite, kaolinite, illite/mica, smectite, vermiculite, chlorite, iron oxide, quartz, non-crystalline, and others. Using a global soil map, a global dataset of soil clay-size mineral distribution was developed at resolutions of 2' to 2° grid cells. The data uncertainty associated with data variability and assumption was evaluated using a Monte Carlo method, and validity of the clay-size mineral distribution obtained in this study was examined by comparing with other datasets. The global soil clay data offer spatially explicit studies on terrestrial biogeochemical cycles, dust emission to the atmosphere, and other interdisciplinary earth sciences. PMID:28829435

Toxicological evaluation of clay minerals and derived nanocomposites: a review.

PubMed

Maisanaba, Sara; Pichardo, Silvia; Puerto, María; Gutiérrez-Praena, Daniel; Cameán, Ana M; Jos, Angeles

2015-04-01

Clays and clay minerals are widely used in many facets of our society. This review addresses the main clays of each phyllosilicate groups, namely, kaolinite, montmorillonite (Mt) and sepiolite, placing special emphasis on Mt and kaolinite, which are the clays that are more frequently used in food packaging, one of the applications that are currently exhibiting higher development. The improvements in the composite materials obtained from clays and polymeric matrices are remarkable and well known, but the potential toxicological effects of unmodified or modified clay minerals and derived nanocomposites are currently being investigated with increased interest. In this sense, this work focused on a review of the published reports related to the analysis of the toxicological profile of commercial and novel modified clays and derived nanocomposites. An exhaustive review of the main in vitro and in vivo toxicological studies, antimicrobial activity assessments, and the human and environmental impacts of clays and derived nanocomposites was performed. From the analysis of the scientific literature different conclusions can be derived. Thus, in vitro studies suggest that clays in general induce cytotoxicity (with dependence on the clay, concentration, experimental system, etc.) with different underlying mechanisms such as necrosis/apoptosis, oxidative stress or genotoxicity. However, most of in vivo experiments performed in rodents showed no clear evidences of systemic toxicity even at doses of 5000mg/kg. Regarding to humans, pulmonary exposure is the most frequent, and although clays are usually mixed with other minerals, they have been reported to induce pneumoconiosis per se. Oral exposure is also common both intentionally and unintentionally. Although they do not show a high toxicity through this pathway, toxic effects could be induced due to the increased or reduced exposure to mineral elements. Finally, there are few studies about the effects of clay minerals on wildlife, with laboratory trials showing contradictory outcomes. Clay minerals have different applications in the environment, thus with a strict control of the concentrations used, they can provide beneficial uses. Despite the extensive number of reports available, there is also a need of systematic in vitro-in vivo extrapolation studies, with still scarce information on toxicity biomarkers such as inmunomodulatory effects or alteration of the genetic expression. In conclusion, a case by case toxicological evaluation is required taking into account that different clays have their own toxicological profiles, their modification can change this profile, and the potential increase of the human/environmental exposure to clay minerals due to their novel applications. Copyright © 2014 Elsevier Inc. All rights reserved.

Boosting subsurface life: is subseafloor sediment a natural catalyst for radiolytic hydrogen production?

NASA Astrophysics Data System (ADS)

Sauvage, J.; Graham, D.; Spivack, A. J.; Dunlea, A. G.; Murray, R. W.; D'Hondt, S.

2014-12-01

Naturally occurring production of molecular hydrogen (H2) by water radiolysis may be a fundamentally important source of electron donors (energy) for life in subsurface environments where organic matter is scarce. Previous studies with very high gamma radiation rates and wet mineral phases have reported high H2 production relative to production from water radiolysis in the absence of solid phases. Numerical calculations by other previous studies have predicted enhanced H2 production from seawater radiolysis relative to pure water radiolysis, due to the interaction of anions with hydroxyl radicals. Given these reports, the potential catalytic influences of solid and dissolved chemical phases on radiolytic H2 production need to be carefully quantified in order to fully evaluate the role of radiolytic H2 as a microbial energy source. For such quantification, we undertook gamma-irradiation experiments with pure water, deep ocean water and mixtures (slurries, φ = 0.85) of seawater with: North Pacific abyssal clay and calcareous oozes, coastal sediment, zirconium dioxide, and zeolite. We carried out our experiments at the Rhode Island Nuclear Science Center using a 37Cesium source at low dose rates (up to 0.1 Gy/hr). Our results to date include the following. First, the per-dose radiolytic H2 yield of pure water at low dose rates is directly comparable to the per-dose yield at much higher dose rates (ca. 1 kGy/hr); this result indicates that H2 production rate is linearly related to radiation dose rate across four orders of magnitude. Second, there is no statistically significant difference (90% confidence limit) between the radiolytic H2 yield from pure water and that from seawater; this result rules out influence of abundant seawater salts on H2 yield from water radiolysis. Third, H2 production from a mixture of abyssal clay and seawater is 25% higher than the yield from pure water. This enhanced yield is consistent with catalysis of radiolytic H2 production by zeolite.

Unravelling the Paleoenvironmental and Diagenetic History of Fluviolacustrine Sediments from a Northern Kenya Rift Basin Through Analysis of HSPDP West Turkana-Kaitio Core Material

NASA Astrophysics Data System (ADS)

Rabideaux, N. M.; Chaudhary, M. S.; Deocampo, D.; Feibel, C. S.; Cohen, A. S.

2016-12-01

The Hominin Sites and Paleolakes Drilling Project (HSPDP) collected sediment cores from six rift basins in Ethiopia and Kenya. The goal of HSPDP is to construct high-resolution records of environmental change, and to understand how those changes relate to early human evolution and cultural adaptations. The West Turkana-Kaitio (WTK) site was targeted due to the abundant archeological and paleontological artifacts and fossils discovered around the basin. We conducted XRD and XRF analyses on HSPDP-WTK core material to construct a high-resolution record of paleoenvironmental conditions in the Kenya Rift during the Early Pleistocene ( 1.9-1.35 Ma). Mineralogical and geochemical trends were also used to identify the diagenetic history of fluviolacustrine sediments in the basin. The bulk mineralogy is comprised of mostly detrital feldspars, muscovite, α-quartz, and carbonates. Zeolites are present in intervals throughout the core, possibly suggesting pulses of increased salinity. Oxides and S-bearing minerals are abundant from 100-170 mbs, which may be indicative of redox and or hydrothermal processes in that interval. The lowermost portion of the core contains α- and β-quartz, pyrite and zeolites, suggesting either low-oxygen saline conditions or hydrothermal activity. Oriented clay analysis indicated multiple intervals of diagenesis, with the illitization of smectite related to hydrothermal and or microbial activity. Clay analysis provided evidence for a low degree of illitization in the upper portion of the core, whereas mixed-layered illite-smectite (I/S) contained 30-50% illite proximal to fault breccia and up to 70% illite below the faulted section, indicative of significant alteration in the lowermost portion of the core. Coupled mineralogical and geochemical analysis revealed a complex alteration history in the basin indicated by: 1) the presence of mixed-layer I/S throughout the 216 m core; 2) pronounced alteration proximal to faulting; and 3) authigenic silicates and pyrite in the basal section of the core.

Formation of replicating saponite from a gel in the presence of oxalate: implications for the formation of clay minerals in carbonaceous chondrites and the origin of life.

PubMed

Schumann, Dirk; Hartman, Hyman; Eberl, Dennis D; Sears, S Kelly; Hesse, Reinhard; Vali, Hojatollah

2012-06-01

The potential role of clay minerals in the abiotic origin of life has been the subject of ongoing debate for the past several decades. At issue are the clay minerals found in a class of meteorites known as carbonaceous chondrites. These clay minerals are the product of aqueous alteration of anhydrous mineral phases, such as olivine and orthopyroxene, that are often present in the chondrules. Moreover, there is a strong correlation in the occurrence of clay minerals and the presence of polar organic molecules. It has been shown in laboratory experiments at low temperature and ambient pressure that polar organic molecules, such as the oxalate found in meteorites, can catalyze the crystallization of clay minerals. In this study, we show that oxalate is a robust catalyst in the crystallization of saponite, an Al- and Mg-rich, trioctahedral 2:1 layer silicate, from a silicate gel at 60°C and ambient pressure. High-resolution transmission electron microscopy analysis of the saponite treated with octadecylammonium (n(C)=18) cations revealed the presence of 2:1 layer structures that have variable interlayer charge. The crystallization of these differently charged 2:1 layer silicates most likely occurred independently. The fact that 2:1 layer silicates with variable charge formed in the same gel has implications for our understanding of the origin of life, as these 2:1 clay minerals most likely replicate by a mechanism of template-catalyzed polymerization and transmit the charge distribution from layer to layer. If polar organic molecules like oxalate can catalyze the formation of clay-mineral crystals, which in turn promote clay microenvironments and provide abundant adsorption sites for other organic molecules present in solution, the interaction among these adsorbed molecules could lead to the polymerization of more complex organic molecules like RNA from nucleotides on early Earth.

Formation of replicating saponite from a gel in the presence of oxalate: implications for the formation of clay minerals in carbonaceous chondrites and the origin of life

USGS Publications Warehouse

Schumann, Dirk; Hartman, Hyman; Eberl, Dennis D.; Sears, S. Kelly; Hesse, Reinhard; Vali, Hojatollah

2012-01-01

The potential role of clay minerals in the abiotic origin of life has been the subject of ongoing debate for the past several decades. At issue are the clay minerals found in a class of meteorites known as carbonaceous chondrites. These clay minerals are the product of aqueous alteration of anhydrous mineral phases, such as olivine and orthopyroxene, that are often present in the chondrules. Moreover, there is a strong correlation in the occurrence of clay minerals and the presence of polar organic molecules. It has been shown in laboratory experiments at low temperature and ambient pressure that polar organic molecules, such as the oxalate found in meteorites, can catalyze the crystallization of clay minerals. In this study, we show that oxalate is a robust catalyst in the crystallization of saponite, an Al- and Mg-rich, trioctahedral 2:1 layer silicate, from a silicate gel at 60°C and ambient pressure. High-resolution transmission electron microscopy analysis of the saponite treated with octadecylammonium (n(C)=18) cations revealed the presence of 2:1 layer structures that have variable interlayer charge. The crystallization of these differently charged 2:1 layer silicates most likely occurred independently. The fact that 2:1 layer silicates with variable charge formed in the same gel has implications for our understanding of the origin of life, as these 2:1 clay minerals most likely replicate by a mechanism of template-catalyzed polymerization and transmit the charge distribution from layer to layer. If polar organic molecules like oxalate can catalyze the formation of clay-mineral crystals, which in turn promote clay microenvironments and provide abundant adsorption sites for other organic molecules present in solution, the interaction among these adsorbed molecules could lead to the polymerization of more complex organic molecules like RNA from nucleotides on early Earth.

Desorption and mobility mechanisms of co-existing polycyclic aromatic hydrocarbons and heavy metals in clays and clay minerals.

PubMed

Saeedi, Mohsen; Li, Loretta Y; Grace, John R

2018-05-15

The effects of soil components such as clay minerals and as humic acids, as well as co-existing metals and polycyclic aromatic hydrocarbons, on desorption and mobility are examined. Three types of artificially blended clay and clay mineral mixtures (pure kaolinite, kaolinite + sand and kaolinite + sand + bentonite), each with different humic acid content, were tested for desorption and mobility of acenaphthene, fluorene and fluoranthene by three extracting solutions CaCl 2 (0.01 M) and EDTA (0.01M) with non-ionic surfactants (Tween 80 and Triton X100). Heavy metals (Ni, Pb and Zn) were also studied for desorption and mobility. The influence of co-present metals on simultaneous desorption and mobility of PAHs was investigated as well. The results showed that <10% of metals in the clay mineral mixtures were mobile. Combined EDTA and non-ionic solutions can enhance the desorption and mobility of PAHs to >80% in clay mineral mixtures containing no sand, while in the same soils containing ∼40% sand, the desorption exceeded 90%. Heavy metals, as well as increasing humic acids content in the clay mineral mixtures, decreased the desorption and mobility of PAHs, especially for soils containing no sand, and for fluoranthene compared with fluorene and acenaphthene. Copyright © 2018 Elsevier Ltd. All rights reserved.

The effects of worms, clay and biochar on CO2 emissions during production and soil application of co-composts

NASA Astrophysics Data System (ADS)

Barthod, Justine; Rumpel, Cornélia; Paradelo, Remigio; Dignac, Marie-France

2016-12-01

In this study we evaluated CO2 emissions during composting of green wastes with clay and/or biochar in the presence and absence of worms (species of the genus Eisenia), as well as the effect of those amendments on carbon mineralization after application to soil. We added two different doses of clay, biochar or their mixture to pre-composted green wastes and monitored carbon mineralization over 21 days in the absence or presence of worms. The resulting co-composts and vermicomposts were then added to a loamy Cambisol and the CO2 emissions were monitored over 30 days in a laboratory incubation. Our results indicated that the addition of clay or clay/biochar mixture reduced carbon mineralization during co-composting without worms by up to 44 %. In the presence of worms, CO2 emissions during composting increased for all treatments except for the low clay dose. The effect of the amendments on carbon mineralization after addition to soil was small in the short term. Overall, composts increased OM mineralization, whereas vermicomposts had no effect. The presence of biochar reduced OM mineralization in soil with respect to compost and vermicompost without additives, whereas clay reduced mineralization only in the composts. Our study indicates a significant role of the conditions of composting on mineralization in soil. Therefore, the production of a low CO2 emission amendment requires optimization of feedstocks, co-composting agents and worm species.

Oily wastewater treatment by adsorption-membrane filtration hybrid process using powdered activated carbon, natural zeolite powder and low cost ceramic membranes.

PubMed

Rasouli, Yaser; Abbasi, Mohsen; Hashemifard, Seyed Abdollatif

2017-08-01

In this research, four types of low cost and high performance ceramic microfiltration (MF) membranes have been employed in an in-line adsorption-MF process for oily wastewater treatment. Mullite, mullite-alumina, mullite-alumina-zeolite and mullite-zeolite membranes were fabricated as ceramic MF membranes by low cost kaolin clay, natural zeolite and α-alumina powder. Powdered activated carbon (PAC) and natural zeolite powder in concentrations of 100-800 mg L -1 were used as adsorbent agent in the in-line adsorption-MF process. Performance of the hybrid adsorption-MF process for each concentration of PAC and natural zeolite powder was investigated by comparing quantity of permeation flux (PF) and total organic carbon (TOC) rejection during oily wastewater treatment. Results showed that by application of 400 mg L -1 PAC in the adsorption-MF process with mullite and mullite-alumina membranes, TOC rejection was enhanced up to 99.5% in comparison to the MF only process. An increasing trend was observed in PF by application of 100-800 mg L -1 PAC. Also, results demonstrated that the adsorption-MF process with natural zeolite powder has higher performance in comparison to the MF process for all membranes except mullite-alumina membranes in terms of PF. In fact, significant enhancement of PF and TOC rejection up to 99.9% were achieved by employing natural zeolite powder in the in-line adsorption-MF hybrid process.

[What a physician should know about zeolites].

PubMed

Boranić, M

2000-01-01

Zeolites are natural and synthetic hydrated crystalline aluminosilicates endowed with absorptive and ion exchange properties. They have found numerous and multifarous applications--in industry as catalysts and absorbents, in water sanitation for the removal of ammonia and heavy metals, in agriculture as fertilizers, and in animal husbandry as the absorbents of excreted material and as food additives. Medical applications have included the use in filtration systems for anesthesia or dialysis and as the contrast materials in NMR imaging. Recently, zeolite powders for external use have found application as deodorants, antimycotic agents and wound dressings. Peroral use of encapsulated zeolite powders enriched with vitamins, oligoelements or other ingredients has been claimed to exert beneficial medical effects. Ingestion of zeolites may be considered analogous to the clay eating (geophagia), considered in traditional medicine as a remedy for various illnesses. Being amphoteric, zeolites are partly soluble in acid or alkaline media, but within the physiological pH range the solubility is generally low. Minimal amounts of free aluminium or silicium from the ingested zeolites are resorbed from the gut. The bulk of ingested zeolite probably remains undissolved in the gut. In view of the ion exchange properties, zeolites may be expected to change the ionic content, pH and buffering capacity of the gastrointestinal secretions and to affect the transport through the intestinal epithelium. In addition, zeolites could affect the bacterial flora and the resorption of bacterial products, vitamins and oligoelements. The contact of zeolite particles with gastrointestinal mucosa may elicit the secretion of cytokines with local and systemic actions. Reactive silicium ions might react with biomolecules of the intestinal epithelium, and if resorbed, do so in other cells. Mutagenic and carcinogenic effects of zeolite particles have been described, resembling such effects of asbestos fibers. Thus, local and systemic effects of zeolites may be complex and interrelated, and an objective assessment requires appropriate experimental models.

Erionite and other fibrous zeolites in volcanic environments: the need for a risk assessment in Italy

NASA Astrophysics Data System (ADS)

Cavallo, A.; Rimoldi, B.

2012-04-01

In many European countries in the '90s there was a significant increase in mortality linked to mesothelioma, a cancer of the lung, involving pleural, pericardial and peritoneal mesothelial cells, which unfortunately has no cure at present. Though most of these cases have been attributed to t asbestos, in Italy at least 17% of cases of mesothelioma is still not fully explained. In the years between 1990 and 2000, it was discovered that the inhalation of erionite fibers (a zeolite group mineral, that can be found in altered volcanic rocks) was the cause of a regional epidemic of mesothelioma in some villages of Cappadocia (Turkey). Erionite, in fact, was recently included in Class 1 (highly carcinogenic) by the World Health Organization, up to 800 times more carcinogenic than asbestos; on the other hand, little is known about the toxicity of other fibrous zeolites, commonly intergrown with erionite, such as offretite and mordenite. Erionite was reported in different regions of Italy; nevertheless, a systematic mapping of its distribution, the quantification of its presence in rocks and data about airborne fibers are still missing. We carried out first preliminary sampling in Veneto, in Tertiary volcanic rocks, mainly hydrothermally altered basalts. The first mineralogical investigations by means of XRPD, SEM-EDS and OM confirmed the presence of small amounts of erionite and abundant fibrous offretite, in vugs of basaltic rocks. Intergrowths and overgrowths with other fibrous minerals are quite common, and the morphological-chemical similarities among these zeolites pose a special analytical problem, with the need of combining different techniques. Our first findings, combined with the fact that zeolites are important industrial minerals, emphasize the need of a risk assessment in Italy and Europe, because there are no systematic studies on the distribution of erionite or similar fibrous zeolites in the environment. The knowledge of the epidemiology of mesothelioma linked to erionite in Italy is extremely scarce: INAIL, through its database of occupational diseases, can provide essential information for epidemiological research. An effective risk assessment in Italy will require coordinated actions from government agencies, local health authorities, Universities and research centers, in order to record the actual presence of fibrous zeolites, recognizing mineral species and quantifying their abundance in rock deposits. The different geological conditions through time of volcanic deposits will be compared with an updated "database" on the physical-chemical-geological conditions of formation of zeolites. In sites where the presence of fibrous zeolites has been validated by laboratory tests, we will proceed with accurate field surveys and sampling campaigns, in order to determine detailed geological-stratigraphic and structural features, and resolving precisely the thickness, areal extent and volume of lithostratigraphic units containing these minerals. These data will be entered into a GIS to produce a result that can be used immediately and in the long-period by research institutes, local authorities and regional agencies for environmental protection. In sites where the presence of hazardous fibrous minerals has been validated, we will plan airborne fibers sampling campaigns, and we will assess the extent of airborne dispersion produced by natural agents and by man activity. In the case that these sites host active mining or quarrying activities, we will quantify the airborne fibers contamination at workplaces and propose measures for environmental risk mitigation.

Kinetics and Products of Chromium(VI) Reduction by Iron(II/III)-Bearing Clay Minerals.

PubMed

Joe-Wong, Claresta; Brown, Gordon E; Maher, Kate

2017-09-05

Hexavalent chromium is a water-soluble pollutant, the mobility of which can be controlled by reduction of Cr(VI) to less soluble, environmentally benign Cr(III). Iron(II/III)-bearing clay minerals are widespread potential reductants of Cr(VI), but the kinetics and pathways of Cr(VI) reduction by such clay minerals are poorly understood. We reacted aqueous Cr(VI) with two abiotically reduced clay minerals: an Fe-poor montmorillonite and an Fe-rich nontronite. The effects of ionic strength, pH, total Fe content, and the fraction of reduced structural Fe(II) [Fe(II)/Fe(total)] were examined. The last variable had the largest effect on Cr(VI) reduction kinetics: for both clay minerals, the rate constant of Cr(VI) reduction varies by more than 3 orders of magnitude with Fe(II)/Fe(total) and is described by a linear free energy relationship. Under all conditions examined, Cr and Fe K-edge X-ray absorption near-edge structure spectra show that the main Cr-bearing product is a Cr(III)-hydroxide and that Fe remains in the clay structure after reacting with Cr(VI). This study helps to quantify our understanding of the kinetics of Cr(VI) reduction by Fe(II/III)-bearing clay minerals and may improve predictions of Cr(VI) behavior in subsurface environments.

Studies on thermal reactions and sintering behaviour of red clays by irreversible dilatometry

NASA Astrophysics Data System (ADS)

Anil, Asha; Misra, S. N.; Misra, N. M.

2018-05-01

Thermal behavior of clays strongly influences that of ceramic bodies made thereof and hence, its study is must for assessing its utility in ceramic products as well as to set the body composition. Irreversible dilatometry is an effective thermal analysis tool for evaluating thermal reactions as well as sintering behavior of clays or clay based ceramic bodies. In this study, irreversible dilatometry of four red clay samples (S, M, R and G) of Gujarat region, which vary in their chemical and mineralogical compositions was carried out using a Dilatometer and compared. Chemical analysis and XRD of red clays were carried out. XRD showed that major clay minerals in S, M and R clays are kaolinite. However, clay marked R and G showed presence of both kaolinite and illite and /muscovite. Presence of non-clay minerals such as hematite, quartz, anatase were also observed in all clays. XRD results were in agreement with chemical analyses results. Rational analyses showed variation in amount of clay and non-clay minerals in red clay samples. Evaluation of dilatometric curves showed that clay marked as S, M and R exhibit patterns typical for kaolinitic clays. Variation in linear expansion (up to 550°C) and shrinkage (above 550°C) between these three clays was found to be related to difference in amount of quartz and kaolinite respectively. However, dilatometric curve of G exhibit a pattern similar to that for an illitic clay. This study confirmed that sintering of investigated kaolinitic and illitic and / muscovitic red clays initiates at above 1060°C and 860°C respectively and this behaviour strongly depends upon type and amount of minerals and their chemical compositions.

Applications for special-purpose minerals at a lunar base

NASA Technical Reports Server (NTRS)

Ming, Douglas W.

1992-01-01

Maintaining a colony on the Moon will require the use of lunar resources to reduce the number of launches necessary to transport goods from the Earth. It may be possible to alter lunar materials to produce minerals or other materials that can be used for applications in life support systems at a lunar base. For example, mild hydrothermal alteration of lunar basaltic glasses can produce special-purpose minerals (e.g., zeolites, smectites, and tobermorites) that in turn may be used in life support, construction, waste renovation, and chemical processes. Zeolites, smectites, and tobermorites have a number of potential applications at a lunar base. Zeolites are hydrated aluminosilicates of alkali and alkaline earth cations that possess infinite, three-dimensional crystal structures. They are further characterized by an ability to hydrate and dehydrate reversibly and to exchange some of their constituent cations, both without major change of structure. Based on their unique absorption, cation exchange, molecular sieving, and catalytic properties, zeolites may be used as a solid support medium for the growth of plants, as an adsorption medium for separation of various gases (e.g., N2 from O2), as catalysts, as molecular sieves, and as a cation exchanger in sewage-effluent treatment, in radioactive waste disposal, and in pollution control. Smectites are crystalline, hydrated 2:1 layered aluminosilicates that also have the ability to exchange some of their constituent cations. Like zeolites, smectites may be used as an adsorption medium for waste renovation, as adsorption sites for important essential plant growth cations in solid support plant growth mediums (i.e., 'soils'), as cation exchangers, and in other important application. Tobermorites are cystalline, hydrated single-chained layered silicates that have cation-exchange and selectivity properties between those of smectites and most zeolites. Tobermorites may be used as a cement in building lunar base structures, as catalysts, as media for nuclear and hazardous waste disposal, as exchange media for waste-water treatment, and in other potential applications. Special-purpose minerals synthesized at a lunar base may also have important applications at a space station and for other planetary missions. New technologies will be required at a lunar base to develop life support systems that are self-sufficient, and the use of special-purpose minerals may help achieve this self-sufficiency.

Exploration of novel multifunctional open graded friction courses for in-situ highway runoff treatment.

DOT National Transportation Integrated Search

2014-07-01

This study found that the possible functional additives such as bentonite, zeolite, and clay : cannot increase the physical and mechanical properties of PCP, neither the removal of Cu and : Zn. Lime is effective in enhancing the physical and mechanic...

An Innovative Design of a Clay-Zeolite Medium for the Adsorption of Total Phosphorus from Wastewater.

PubMed

Ciosek, Amanda Lidia; Luk, Grace K; Warner, Michèle; Warner, R Anthony

2016-02-01

Phosphorus significantly influences the eutrophication process, modifying the quality of waterways and habitat, especially in stagnant waterbodies exposed to septic tank effluent at high nutrient levels. This research explores the development of a cost-effective, efficient, and affordable on-site wastewater treatment system targeted as total phosphorus (TP) removal technology. The research objective is to demonstrate the TP removal efficiency of an optimized clay-zeolite medium by chemical adsorption. The study observes the effects of pellet medium design and modifications, influent concentrations, and contact time. Following various stages of optimization, the preliminary testing achieves a 45 ± 1.8% removal after 45 minutes of contact time. The optimized pellets are contained within a five-layer bench-scale model, achieving equilibrium TP removal of 72 ± 2.9% after 3 hours. Theoretical extrapolation to 12 contact hours indicates an achievement of 88% removal is possible. The results show a positive correlation with the linearized Langmuir and Freundlich adsorption isotherms.

Hydrovolcanic and Hydrothermal Biomediated Mineral Growth in Basaltic Tuff, Surtsey Volcano, Iceland

NASA Astrophysics Data System (ADS)

Jackson, M. D.; Couper, S.; Ivarsson, M.; Stan, C. V.; Tamura, N.; Miyagi, L. M.; Moore, J. G.

2017-12-01

Fine-scale analyses of hydroclasts in 1979 Surtsey basaltic tuff drill core provide new methods for examining hydrovolcanic and hydrothermal magma-rock influences on biomediated alteration in palagonitized submarine tephra. Synchrotron source X-ray microdiffraction and microfluorescence studies from Advanced Light Source beamline 12.3.2, epifluorescent UVA illumination microscopy, S/TEM EDX compositional analyses, and Raman spectroscopy define diverse nanocrystalline clay mineral structures at 137.9 m depth (93.8 °C (1980)) and 102.6 m depth (141.3 °C (1980)). At 137.9 m, olivine contains endolithic microborings; vermicular microstructures in altered glass contain nontronite exhibiting crystallographic preferred orientation; and 75-150 µm sub-circular microstructures in altered glass contain Al-tobermorite, a calcium-silicate-hydrate with 11.3 Å interlayer spacing, zeolite, and epifluorescent, thread-like structures. At 102.6 m depth, concentrically-layered microstructures occur in altered glass and altered olivine. These have nontronite crystallographic preferred orientations that rotate around a longitudinal axis commonly occupied by a 10-80 µm long, epifluorescent thread-like structure. Pronounced carbon concentrations detected by S/TEM EDX trace layer boundaries. First-order Raman bands at 1370 cm-1 (disorder-related) and at 1580 cm-1 (order-related), and second-order bands at 2500-3300 cm-1 (overtone scattering) detect degraded organic carbonaceous matter, a strong indication of biological origin. Sub-circular nanostructures in altered glass at 137.9 m depth show similar spectra. Borehole fluid temperatures at 102.6 m, 141.3 °C in 1980, exceeded 130 °C, the assumed limit for growth of microorganisms, however. Previous analyses suggest an early low temperature episode in submarine deposits, prior to development of a hydrothermal system driven by 1964-1967 magmatic intrusions. The abundant traces of biomediated nanocrystalline clay mineral growth validate this hypothesis. Hydrovolcanic fragmentation apparently increased ingress of seawater from the marine biosphere. Both eruptive and hydrothermal water-rock interactions influenced palagonitic alteration at the submillimeter scale during diverse temperature chronologies in the very young volcano.

Enhanced cellular preservation by clay minerals in 1 billion-year-old lakes.

PubMed

Wacey, David; Saunders, Martin; Roberts, Malcolm; Menon, Sarath; Green, Leonard; Kong, Charlie; Culwick, Timothy; Strother, Paul; Brasier, Martin D

2014-07-28

Organic-walled microfossils provide the best insights into the composition and evolution of the biosphere through the first 80 percent of Earth history. The mechanism of microfossil preservation affects the quality of biological information retained and informs understanding of early Earth palaeo-environments. We here show that 1 billion-year-old microfossils from the non-marine Torridon Group are remarkably preserved by a combination of clay minerals and phosphate, with clay minerals providing the highest fidelity of preservation. Fe-rich clay mostly occurs in narrow zones in contact with cellular material and is interpreted as an early microbially-mediated phase enclosing and replacing the most labile biological material. K-rich clay occurs within and exterior to cell envelopes, forming where the supply of Fe had been exhausted. Clay minerals inter-finger with calcium phosphate that co-precipitated with the clays in the sub-oxic zone of the lake sediments. This type of preservation was favoured in sulfate-poor environments where Fe-silicate precipitation could outcompete Fe-sulfide formation. This work shows that clay minerals can provide an exceptionally high fidelity of microfossil preservation and extends the known geological range of this fossilization style by almost 500 Ma. It also suggests that the best-preserved microfossils of this time may be found in low-sulfate environments.

Enhanced cellular preservation by clay minerals in 1 billion-year-old lakes

PubMed Central

Wacey, David; Saunders, Martin; Roberts, Malcolm; Menon, Sarath; Green, Leonard; Kong, Charlie; Culwick, Timothy; Strother, Paul; Brasier, Martin D.

2014-01-01

Organic-walled microfossils provide the best insights into the composition and evolution of the biosphere through the first 80 percent of Earth history. The mechanism of microfossil preservation affects the quality of biological information retained and informs understanding of early Earth palaeo-environments. We here show that 1 billion-year-old microfossils from the non-marine Torridon Group are remarkably preserved by a combination of clay minerals and phosphate, with clay minerals providing the highest fidelity of preservation. Fe-rich clay mostly occurs in narrow zones in contact with cellular material and is interpreted as an early microbially-mediated phase enclosing and replacing the most labile biological material. K-rich clay occurs within and exterior to cell envelopes, forming where the supply of Fe had been exhausted. Clay minerals inter-finger with calcium phosphate that co-precipitated with the clays in the sub-oxic zone of the lake sediments. This type of preservation was favoured in sulfate-poor environments where Fe-silicate precipitation could outcompete Fe-sulfide formation. This work shows that clay minerals can provide an exceptionally high fidelity of microfossil preservation and extends the known geological range of this fossilization style by almost 500 Ma. It also suggests that the best-preserved microfossils of this time may be found in low-sulfate environments. PMID:25068404

Ground Truthing Orbital Clay Mineral Observations with the APXS Onboard Mars Exploration Rover Opportunity

NASA Technical Reports Server (NTRS)

Schroeder, C.; Gellert, R.; VanBommel, S.; Clark, B. C.; Ming, D. W.; Mittlefehldt, D. S.; Yen, A. S.

2016-01-01

NASA's Mars Exploration Rover Opportunity has been exploring approximately 22 km diameter Endeavour crater since 2011. Its rim segments predate the Hesperian-age Burns formation and expose Noachian-age material, which is associated with orbital Fe3+-Mg-rich clay mineral observations [1,2]. Moving to an orders of magnitude smaller instrumental field of view on the ground, the clay minerals were challenging to pinpoint on the basis of geochemical data because they appear to be the result of near-isochemical weathering of the local bedrock [3,4]. However, the APXS revealed a more complex mineral story as fracture fills and so-called red zones appear to contain more Al-rich clay minerals [5,6], which had not been observed from orbit. These observations are important to constrain clay mineral formation processes. More detail will be added as Opportunity is heading into her 10th extended mission, during which she will investigate Noachian bedrock that predates Endeavour crater, study sedimentary rocks inside Endeavour crater, and explore a fluid-carved gully. ESA's ExoMars rover will land on Noachian-age Oxia Planum where abundant Fe3+-Mg-rich clay minerals have been observed from orbit, but the story will undoubtedly become more complex once seen from the ground.

Satellite-derived mineral mapping and monitoring of weathering, deposition and erosion

PubMed Central

Cudahy, Thomas; Caccetta, Mike; Thomas, Matilda; Hewson, Robert; Abrams, Michael; Kato, Masatane; Kashimura, Osamu; Ninomiya, Yoshiki; Yamaguchi, Yasushi; Collings, Simon; Laukamp, Carsten; Ong, Cindy; Lau, Ian; Rodger, Andrew; Chia, Joanne; Warren, Peter; Woodcock, Robert; Fraser, Ryan; Rankine, Terry; Vote, Josh; de Caritat, Patrice; English, Pauline; Meyer, Dave; Doescher, Chris; Fu, Bihong; Shi, Pilong; Mitchell, Ross

2016-01-01

The Earth’s surface comprises minerals diagnostic of weathering, deposition and erosion. The first continental-scale mineral maps generated from an imaging satellite with spectral bands designed to measure clays, quartz and other minerals were released in 2012 for Australia. Here we show how these satellite mineral maps improve our understanding of weathering, erosional and depositional processes in the context of changing weather, climate and tectonics. The clay composition map shows how kaolinite has developed over tectonically stable continental crust in response to deep weathering during northwardly migrating tropical conditions from 45 to 10 Ma. The same clay composition map, in combination with one sensitive to water content, enables the discrimination of illite from montmorillonite clays that typically develop in large depositional environments over thin (sinking) continental crust such as the Lake Eyre Basin. Cutting across these clay patterns are sandy deserts that developed <10 Ma and are well mapped using another satellite product sensitive to the particle size of silicate minerals. This product can also be used to measure temporal gains/losses of surface clay caused by periodic wind erosion (dust) and rainfall inundation (flood) events. The accuracy and information content of these satellite mineral maps are validated using published data. PMID:27025192

[Analysis of XRD spectral characteristics of soil clay mineral in two typical cultivated soils].

PubMed

Zhang, Zhi-Dan; Luo, Xiang-Li; Jiang, Hai-Chao; Li, Qiao; Shen, Cong-Ying; Liu, Hang; Zhou, Ya-Juan; Zhao, Lan-Po; Wang, Ji-Hong

2014-07-01

The present paper took black soil and chernozem, the typical cultivated soil in major grain producing area of Northeast, as the study object, and determinated the soil particle composition characteristics of two cultivated soils under the same climate and location. Then XRD was used to study the composition and difference of clay mineral in two kinds of soil and the evolutionary mechanism was explored. The results showed that the two kinds of soil particles were composed mainly of the sand, followed by clay and silt. When the particle accumulation rate reached 50%, the central particle size was in the 15-130 microm interval. Except for black soil profile of Shengli Xiang, the content of clay showed converse sequence to the central particle in two soils. Clay accumulated under upper layer (18.82%) in black soil profile while under caliche layer (17.41%) in chernozem profile. Clay content was the least in parent material horizon except in black profile of Quanyanling. Analysis of clay XRD atlas showed that the difference lied in not only the strength of diffraction peak, but also in the mineral composition. The main contents of black soil and chernozem were both 2 : 1 clay, the composition of black soil was smectite/illite mixed layer-illite-vermiculite and that of chernozem was S/I mixture-illite-montmorillonite, and both of them contained little kaolinite, chlorite, quartz and other primary mineral. This paper used XRD to determine the characteristics of clay minerals comprehensively, and analyzed two kinds of typical cultivated soil comparatively, and it was a new perspective of soil minerals study.

Dehydration-induced luminescence in clay minerals

NASA Technical Reports Server (NTRS)

Coyne, L. M.; Lahav, N.; Lawless, J. G.

1981-01-01

Reports of triboluminescent phenomena in organic crystalline materials prompted a search for related processes in clay minerals. The reported extensive mechanical distortion produced on freezing and drying of montmorillonite was particularly interesting because of studies of condensation reactions in a wet/dry cycled reaction sequence. The discovery of an unusual luminescent process in several clay minerals is reported and its characteristics are described.

Photocatalytic activity of undoped and Ag-doped TiO{sub 2}-supported zeolite for humic acid degradation and mineralization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lazau, C.; Ratiu, C.; National Institute for Research and Development in Microtechnologies, Erou Iancu Nicolae Street, 077190 Bucharest

2011-11-15

Highlights: {yields} Hybrid materials based on natural zeolite and TiO{sub 2} obtained by solid-state reaction. {yields} XRD proved the presence of anatase form of undoped and Ag-doped TiO{sub 2} onto zeolite. {yields} FT-IR spectra evidenced the presence on TiO{sub 2} bounded at the zeolite network. {yields} Ag-doped TiO{sub 2} onto zeolitic matrix exhibited an enhanced photocatalytic activity. -- Abstract: The hybrid materials based on natural zeolite and undoped and Ag-doped TiO{sub 2}, i.e., Z-Na-TiO{sub 2} and Z-Na-TiO{sub 2}-Ag, were successfully synthesized by solid-state reaction in microwave-assisted hydrothermal conditions. Undoped TiO{sub 2} and Ag-doped TiO{sub 2} nanocrystals were previously synthesized bymore » sol-gel method. The surface characterization of undoped TiO{sub 2}/Ag-doped TiO{sub 2} and natural zeolite hybrid materials has been investigated by X-ray diffraction, DRUV-VIS spectroscopy, FT-IR spectroscopy, BET analysis, SEM microscopy and EDX analysis. The results indicated that anatase TiO{sub 2} is the dominant crystalline type as spherical form onto zeolitic matrix. The presence of Ag into Z-Na-TiO{sub 2}-Ag was confirmed by EDX analysis. The DRUV-VIS spectra showed that Z-Na-TiO{sub 2}-Ag exhibited absorption within the range of 400-500 nm in comparison with Z-Na-TiO{sub 2} catalyst. The enhanced photocatalytic activity of Z-Na-TiO{sub 2}-Ag catalyst is proved through the degradation and mineralization of humic acid under ultraviolet and visible irradiation.« less

Changing of Sumatra backswamp peat properties by seawater and zeolite application

NASA Astrophysics Data System (ADS)

Sarifuddin; Nasution, Z.; Rauf, A.; Mulyanto, B.

2018-02-01

This research attempts to improve the properties of backswamp peatsoil originated from Asahan District, North Sumatra Indonesia by adding sea water and zeolite using factorial randomized block design with volume of sea water as first factor, consisting of without seawater, 500 ml, 1000 ml and 1500 ml and second factor are dosages of zeolite consisting of without zeolite, 100 g, 200 g each 10 kgs of wet peat soil. at green house in faculty of agriculture University of Sumatra Utara (USU) Medan, Indonesia. The result showed that the application of seawater decreased pH, C/N and Cation Exchange Capacity and increased of base saturation of peat soil. Adding of zeolite minerals can buffered the increasing of acidity and Electric Conductivity caused by sea water application. Interaction seawater + zeolite decreased of C/N and increased of percent of base saturation.

Clay mineral formation and transformation in rocks and soils

USGS Publications Warehouse

Eberl, D.D.

1983-01-01

Three mechanisms for clay mineral formation (inheritance, neoformation, and transformation) operating in three geological environments (weathering, sedimentary, and diagenetic-hydrothermal) yield nine possibilities for the origin of clay minerals in nature. Several of these possibilities are discussed in terms of the rock cycle. The mineralogy of clays neoformed in the weathering environment is a function of solution chemistry, with the most dilute solutions favoring formation of the least soluble clays. After erosion and transportation, these clays may be deposited on the ocean floor in a lateral sequence that depends on floccule size. Clays undergo little reaction in the ocean, except for ion exchange and the neoformation of smectite; therefore, most clays found on the ocean floor are inherited from adjacent continents. Upon burial and heating, however, dioctahedral smectite reacts in the diagenetic environment to yield mixed-layer illite-smectite, and finally illite. With uplift and weathering, the cycle begins again. Refs.

Sub-glacial Origin of the Hot Springs Bay Valley hydrothermal System, Akutan, Alaska

NASA Astrophysics Data System (ADS)

Stelling, P. L.; Tobin, B.; Knapp, P.

2015-12-01

Exploration for geothermal energy in Hot Springs Bay Valley (HSBV) on Akutan Island, Alaska, has revealed a rich hydrothermal history, including what appears to be a stage of peak activity during a significant glacial period. Alteration mineralogy observed in 754 m of drill core recovered from the outflow zone is dominated by chlorite and includes minor smectite clays, a suite of zeolite species and several moderately high-temperature hydrothermal minerals (epidote/clinozoisite, prehnite, adularia and wairakite). The latter minerals each have minimum formation temperatures exceeding 200 oC, and fluid inclusion results in related calcite crystals indicate temperatures of formation to be as high as 275 oC, some 100 oC hotter than the modern boiling point with depth (BPD) curve at that depth (>62 m). In order to maintain liquid temperatures this high, the pressure during mineralization must have been substantially greater (~680 bar), a pressure change equivalent to erosion of ~280 m of rock (ρ=2.5 g/cm3). Although glacial erosion rates are too low (0.034 mm/yr; Bekele et al., 2003) for this amount of erosion to occur in a single glaciation, glacial melting and ablation are substantially more rapid (~100 mm/yr; Bekele et al., 2003; Person et al., 2012). Thus, a more probable scenario than pure erosion is that peak hydrothermal conditions occurred during a large glacial event, with the added pressure from the overlying ice allowing the high temperature minerals to form closer to the ground surface. Subsequent melting of the ice eroded upper tributary valleys and upper levels of the originally smectite-rich alteration assemblage, explaining the paucity of swelling clays in the region. We present mineralogical, fluid inclusion and geochronologic evidence to support these conclusions, and discuss the general implications of sub-glacial hydrothermal system formation and geothermal resource potential. References: Bekele, E., Rostron, B. and Person, M. (2003) Fluid pressure implications of erosional unloading, basin hydrodynamics and glaciation in the Alberta Basin, Western Canada. J. of Geochem. Exploration, 78-79, 143-7. Person, M., Bense, V., Cohen, D. and Banerjee, A, (2012). Models of ice-sheet hydrogeologic interactions: a review. Geofluids, 12, 58-78

Ostwald ripening of clays and metamorphic minerals

USGS Publications Warehouse

Eberl, D.D.; Srodon, J.; Kralik, M.; Taylor, B.E.; Peterman, Z.E.

1990-01-01

Analyses of particle size distributions indicate that clay minerals and other diagenetic and metamorphic minerals commonly undergo recrystallization by Ostwald ripening. The shapes of their particle size distributions can yield the rate law for this process. One consequence of Ostwald ripening is that a record of the recrystallization process is preserved in the various particle sizes. Therefore, one can determine the detailed geologic history of clays and other recrystallized minerals by separating, from a single sample, the various particle sizes for independent chemical, structural, and isotopic analyses.

Long-term variations of clay mineral composition in the Andaman Sea (IODP Exp. 353 Site U1447): preliminary result

NASA Astrophysics Data System (ADS)

Lee, J.; Khim, B. K.; Cho, H. G.; Kim, S.; 353 Scientists, I. E.

2016-12-01

Clay mineral studies in the Bengal Fan have allowed the reconstruction of the erosional history of the Himalayan-Tibetan complex since the Early Miocene. Several factors such as climate change and tectonic activity are important for the erosion rate of the Himalaya-Tibet complex. IODP Expedition 353 Site U1447 (10°47.4'N, 93°00'E; 1391 mbsl) was drilled on a ridge 45 km offshore Little Andaman Island in the Andaman Sea, penetrating to total depths of 738 m. Riverine sediments supplied mainly by the Irrawaddy and Salween (draining the Indo-Burman Ranges; smectite-rich) and the Ganga/Brahmaputra (draining the Himalaya; illite-rich) via the surface currents have been known to deposit in the Andaman Sea. We measured clay minerals of 38 sediment samples collected from 150 to 737 m CSF-A at Site U1447 in order to reveal long-term variation patterns of clay minerals and their controlling factors. Age reconstruction of Site U1447 aided by shipboard biostratigraphic and paleomagnetic data defined the study interval spanning from the Late Miocene ( 10 Ma) to Early Pleistocene ( 1.25 Ma). At this interval, clay minerals consist mainly of smectite (28-61% with an average of 47%) followed by illite (20-41% with an average of 29%), kaolinite (9-19% with an average of 14%), and chlorite (5-15% with an average of 10%). Variation of clay mineral compositions is divided into three stages; almost consistent variations of all clay minerals (from 750 to 570 m CSF-A; 10.0 to 7.5 Ma), gradual decrease of smectite and increase of illite and chlorite (from 570 to 400 m CSF-A; 7.5 to 4.5 Ma), and great fluctuation of all clay minerals (from 400 to 150 m CSF-A; 4.5 to 1.1 Ma). Such long-term clay mineral changes may be related to provenance switches, tectonic evolution of the source regions, climatic variations, degree of volcanism with basin evolution, sedimentation history by sea level changes or some combination of these factors.

Role of clay minerals in the formation of atmospheric aggregates of Saharan dust

NASA Astrophysics Data System (ADS)

Cuadros, Javier; Diaz-Hernandez, José L.; Sanchez-Navas, Antonio; Garcia-Casco, Antonio

2015-11-01

Saharan dust can travel long distances in different directions across the Atlantic and Europe, sometimes in episodes of high dust concentration. In recent years it has been discovered that Saharan dust aerosols can aggregate into large, approximately spherical particles of up to 100 μm generated within raindrops that then evaporate, so that the aggregate deposition takes place most times in dry conditions. These aerosol aggregates are an interesting phenomenon resulting from the interaction of mineral aerosols and atmospheric conditions. They have been termed "iberulites" due to their discovery and description from aerosol deposits in the Iberian Peninsula. Here, these aggregates are further investigated, in particular the role of the clay minerals in the aggregation process of aerosol particles. Iberulites, and common aerosol particles for reference, were studied from the following periods or single dust events and locations: June 1998 in Tenerife, Canary Islands; June 2001 to August 2002, Granada, Spain; 13-20 August 2012, Granada; and 1-6 June 2014, Granada. Their mineralogy, chemistry and texture were analysed using X-ray diffraction, electron microprobe analysis, SEM and TEM. The mineral composition and structure of the iberulites consists of quartz, carbonate and feldspar grains surrounded by a matrix of clay minerals (illite, smectite and kaolinite) that also surrounds the entire aggregate. Minor phases, also distributed homogenously within the iberulites, are sulfates and Fe oxides. Clays are apparently more abundant in the iberulites than in the total aerosol deposit, suggesting that iberulite formation concentrates clays. Details of the structure and composition of iberulites differ from descriptions of previous samples, which indicates dependence on dust sources and atmospheric conditions, possibly including anthropic activity. Iberulites are formed by coalescence of aerosol mineral particles captured by precursor water droplets. The concentration of clays in the iberulites is suggested to be the result of higher efficiency for clay capture than for the capture of larger mineral grains. The high hygroscopicity of clay minerals probably causes retention of water in the evaporation stage and some secondary minerals (mainly gypsum) are associated with clays.

Lactic acid production on liquid distillery stillage by Lactobacillus rhamnosus immobilized onto zeolite.

PubMed

Djukić-Vuković, Aleksandra P; Mojović, Ljiljana V; Jokić, Bojan M; Nikolić, Svetlana B; Pejin, Jelena D

2013-05-01

In this study, lactic acid and biomass production on liquid distillery stillage from bioethanol production with Lactobacillus rhamnosus ATCC 7469 was studied. The cells were immobilized onto zeolite, a microporous aluminosilicate mineral and the lactic acid production with free and immobilized cells was compared. The immobilization allowed simple cell separation from the fermentation media and their reuse in repeated batch cycles. A number of viable cells of over 10(10) CFU g(-1) of zeolite was achieved at the end of fourth fermentation cycle. A maximal process productivity of 1.69 g L(-1), maximal lactic acid concentration of 42.19 g L(-1) and average yield coefficient of 0.96 g g(-1) were achieved in repeated batch fermentation on the liquid stillage without mineral or nitrogen supplementation. Copyright © 2012 Elsevier Ltd. All rights reserved.

Laboratory study of adsorption and deliquescence on the surface of Mars

NASA Astrophysics Data System (ADS)

Nikolakakos, George; Whiteway, James A.

2018-07-01

A sample of the zeolitic mineral chabazite was subjected to a range of water vapor pressures and temperatures found on present day Mars. Laser Raman scattering was applied to detect the relative amounts of water and carbon dioxide adsorbed by the sample. Results show that zeolites are capable of adsorbing water from the atmosphere on diurnal time scales and that Raman scattering spectroscopy provides a promising method for detecting this process during a landed mission. When the water vapor pressure and temperature were sufficiently low, the zeolite sample also adsorbed carbon dioxide, resulting in the simultaneous adsorption of water and carbon dioxide on the surface mineral grains. Additional experiments were carried out using a mixture of magnesium perchlorate and chabazite. The sample of mixed surface material remained visually unchanged during water adsorption, but was found to darken during deliquescence.

To what extent clay mineralogy affects soil aggregation? Consequences for soil organic matter stabilization

NASA Astrophysics Data System (ADS)

Fernandez-Ugalde, O.; Barré, P.; Hubert, F.; Virto, I.; Chenu, C.; Ferrage, E.; Caner, L.

2012-12-01

Aggregation is a key process for soil functioning as it influences C storage, vulnerability to erosion and water holding capacity. While the influence of soil organic C on aggregation has been documented, much less is known about the role of soil mineralogy. Soils usually contain a mixture of clay minerals with contrasted surface properties, which should result on different abilities of clay minerals to aggregation. We took advantage of the intrinsic mineral heterogeneity of a temperate Luvisol to compare the role of clay minerals (illite, smectite, kaolinite, and mixed-layer illite-smectite) in aggregation. In a first step, grassland and tilled soil samples were fractionated in water in aggregate-size classes according to the hierarchical model of aggregation (Tisdall and Oades, 1982). Clay mineralogy and organic C in the aggregate-size classes were analyzed. The results showed that interstratified minerals containing swelling phases accumulated in aggregated fractions (>2 μm) compared to free clay fractions (<2 μm) in the two land-uses. The accumulation increased from large macro-aggregates (>500 μm) to micro-aggregates (50-250 μm). C concentration and C/N ratio followed the opposite trend. These results constitute a clay mineral-based evidence for the hierarchical model of aggregation, which postulates an increasing importance of the reactivity of clay minerals in the formation of micro-aggregates compared to larger aggregates. In the latter aggregates, formation relies on the physical enmeshment of particles by fungal hyphae, and root and microbial exudates. In a second step, micro-aggregates from the tilled soil samples were submitted to increasingly disaggregating treatments by sonication to evaluate the link between their water stability and clay mineralogy. Micro-aggregates with increasing stability showed an increase of interstratified minerals containing swelling phases and C concentration for low intensities of disaggregation (from 0 to 5 J mL-1). This suggests that swelling phases promote their stability. Swelling phases and organic C decreased for greater intensities of disaggregation. These results and the SEM images taken at different disaggregation intensities indicate that when increasing disaggregation intensity above 5 J mL-1, the recovered material consists on sand particles covered by physical coatings of illite and kaolinite. Our results show that different clay minerals have different contribution to soil aggregation. Swelling phases are especially important for water-stable aggregates formation, whereas illite and kaolinite can either contribute to aggregation or been coated to sand grains in "mineral aggregates", without porosity and organic C protection capability. In conclusion, soils with large proportion of swelling clay minerals have greater potential for carbon storage by occlusion in aggregates and greater resistance to erosion. Tisdall JM, Oades JM (1982) Organic matter and water-stable aggregates in soils. J Soil Sci 62: 141-163.

First Direct Detection of Clay Minerals on Mars

NASA Technical Reports Server (NTRS)

Singer, R. B.; Owensby, P. D.; Clark, R. N.

1985-01-01

Magnesian clays or clay-type minerals were conclusively detected in the martian regolith. Near-IR spectral observations of Mars using the Mauna Kea 2.2-m telescope show weak but definite absorption bands near microns. The absorption band positions and widths match those produced by combined OH stretch and Mg-OH lattice modes and are diagnostic of minerals with structural OH such as clays and amphiboles. Likely candidate minerals include serpentine, talc, hectorite, and sponite. There is no spectral evidence for aluminous hydroxylated minerals. No distinct band occurs at 2.55 microns, as would be expected if carbonates were responsible for the 2.35 micron absorption. High-albedo regions such as Elysium and Utopia have the strongest bands near 2.35 microns, as would be expected for heavily weathered soils. Low-albedo regions such as Iapygia show weaker but distinct bands, consistent with moderate coatings, streaks, and splotches of bright weathered material. In all areas observed, the 2.35-micron absorption is at least three times weaker than would be expected if well-crystallized clay minerals made up the bulk of bright soils on Mars.

Clinoptilolite zeolite influence on inorganic nitrogen in silt loam and sandy agricultural soils

USDA-ARS?s Scientific Manuscript database

Development of best management practices can help improve inorganic nitrogen (N) availability to plants and reduce nitrate-nitrogen (NO3-N) leaching in soils. This study was conducted to determine the influence of the zeolite mineral Clinoptilolite (CL) additions on NO3-N and ammonium-nitrogen (NH4...

Clinoptilolite Zeolite Influence on Inorganic Nitrogen in Silt Loam and Sandy Agricultural Soils

USDA-ARS?s Scientific Manuscript database

Development of best management practices can help improve inorganic nitrogen (N) availability to plants and reduce nitrate-nitrogen (NO3-N) leaching in soils. This study was conducted to determine the influence of the zeolite mineral Clinoptilolite (CL) additions on NO3-N and ammonium-nitrogen (NH4...

Clinoptilolite zeolite influence on nitrogen in a manure-amended sandy agricultural soil

USDA-ARS?s Scientific Manuscript database

Development of best management practices can help improve inorganic nitrogen (N) availability to plants and reduce nitrate-nitrogen (NO3-N) leaching in soils. This study was conducted to determine the influence of the zeolite mineral clinoptilolite (CL) additions on NO3-N and ammonium-nitrogen (NH4-...

POLISHING INDUSTRIAL WASTE STREAM EFFLUENTS USING FLY ASH - NATURAL CLAY SORBENT COMBINATION

EPA Science Inventory

A laboratory evaluation of the use of acidic and basic fly ashes, bentonite, bauxite, illite, kaolinite, zeolite, vermiculite, and activated alumina is presented for polishing a 3.8 x 10 to the 6th power liters per day waste stream from the feldspar mining and processing industry...

Contrasting frictional behaviour of fault gouges containing Mg-rich phyllosilicates

NASA Astrophysics Data System (ADS)

Sanchez Roa, C.; Faulkner, D.; Jimenez Millan, J.; Nieto, F.

2015-12-01

The clay mineralogy of fault gouges has important implications on frictional properties and stability of fault planes. We studied the specific case of the Galera fault zone where fault gouges containing Mg-rich phyllosilicates appear as hydrothermal deposits related to high salinity fluids enriched in Mg2+. These deposits are dominated by sepiolite and palygorskite, both fibrous clay minerals with similar composition to Mg-smectite. The frictional strengths of sepiolite and palygorskite have not yet been determined, however, as they are part of the clay mineral group, it has been assumed that their frictional behaviour would be in line with platy clay minerals. We performed frictional sliding experiments on powdered pure standards and fault rocks in order to establish the frictional behaviour of sepiolite and palygorskite using a triaxial deformation apparatus with a servo-controlled axial loading system and fluid pressure pump. Friction coefficients for palygorskite and sepiolite as monomineralic samples were found to be 0.65 to 0.7 for dry experiments, and 0.45 to 0.5 for water-saturated experiments. Although these fibrous minerals are part of the phyllosilicates group, they show higher friction coefficients and their mechanical behaviour is less stable than platy clay minerals. This difference is a consequence of their stronger structural framework and the discontinuity of water layers. Our results present a contrast in mechanical behaviour between Mg-rich fibrous and platy clay minerals in fault gouges, where smectite is known to considerably reduce friction coefficients and to increase the stability of the fault plane leading to creeping processes. Transformations between saponite and sepiolite have been previously observed and could modify the deformation regime of a fault zone. Constraining the stability conditions and possible mineral reactions or transformations in fault gouges could help us understand the general role of clay minerals in fault stability.

Origin and diagenesis of clay minerals in relation to sandstone paragenesis: An example in eolian dune reservoirs and associated rocks, Permian upper part of the Minnelusa Formation, Powder River basin, Wyoming

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pollastro, R.M.; Schenk, C.J.

Eolian dune sandstones are the principal reservoir rocks in the Permian upper part of the Minnelusa Formation, Powder River basin, Wyoming. These sandstones formed as shorelines retreated and dunes migrated across siliciclastic sabkhas. Sandstones are mainly quartzarenites; on average, clay minerals constitute about 5 wt.% the whole rock. Although present in minor amounts, clay minerals play an important role in the diagenetic evolution of these sandstones. Allogenic clay minerals are present in shaly rock fragments and laminae. Early infiltration of clays into porous sabkha sands commonly form characteristic menisei or bridges between framework grains or, when more extensive, form coatingsmore » or rims on grain surfaces. Authigenic clays include nearly pure smectite, mixed-layer illite/smectite (I/S), and late diagenetic illite and corrensite; these clay minerals are present as pore-lining cements. In addition to the deposition and neoformation of clay minerals throughout sandstone paragenesis, the conversion of smectite to illite occurred as temperatures increased with progressive burial. A temperature of 103C is calculated at a present depth of 3,200 m using a geothermal gradient of 30C/km and a mean annual surface temperature of 7C. After correction for uplift and erosion (250 m), the maximum calculated temperature for the conversion of all random I/S to ordered I/S is 100C. This calculated temperature is in excellent agreement with temperatures of 100-110C implied from I/S geothermometry.« less

The clays of the United States east of the Mississippi River

USGS Publications Warehouse

Ries, Henrich

1903-01-01

Since clays vary mineralogically they vary also chemically, but the plasticity may remain the same through a wide range of chemical composition, and this property is evidently not dependent on the chemical composition alone, but is due rather to some physical cause. The plasticity may be destroyed by heating the clay to a sufficiently high temperature to drive off the chemically combined water. Although varying in their mineral composition, most clays are supposed to contain more or less of the mineral kaolinite (a hydrated silicate of alumina), which is commonly referred to as the clay base or clay substance. The adoption of the latter term has probably arisen from the fact that many have 'considered this mineral to be the cause of plasticity, an idea now known to be somewhat incorrect, because some of the most plastic clays contain but small quantities of kaolinite, and vice versa. 

Comparative study of As (III) and Zn (II) removal from aqueous solutions using Philippine natural zeolite and alumina

NASA Astrophysics Data System (ADS)

Olegario-Sanchez, Eleanor; Pelicano, Christian Mark

2017-12-01

Herein, the heavy metal removal efficiency of Philippine natural zeolite is investigated through a comparative study with commercial alumina (Al2O3). XRD results revealed a high purity crystalline γ-Al2O3 and a natural zeolite having clinoptilolite (Na,K,Ca)2-3Al3(Al,Si)2Si13O36.12H2O and mordenite (Ca, Na2, K2)Al2Si10O24.7H2O as primary component minerals. Micro-pores and plate-like structures were observed on the surface of the natural zeolite. The natural zeolite has shown three times higher removal efficiency for Zn2+ ion than alumina. On the other hand, alumina exhibited comparable but smaller removal efficiency for As3+ as with that of natural zeolite. Alumina showed a higher capability of increasing the pH of both solutions compared with the natural zeolite. Based on removal efficiency and adsorbent costs, Philippine natural zeolite could be used as a low-cost alternative for wastewater treatment.

Investigating Interactions between the Silica and Carbon Cycles during Precipitation and Early Diagenesis of Authigenic Clay/Carbonate-Mineral Associations in the Carbonate Rock Record

NASA Astrophysics Data System (ADS)

McKenzie, J. A.; Francisca Martinez Ruiz, F.; Sanchez-Roman, M.; Anjos, S.; Bontognali, T. R. R.; Nascimento, G. S.; Vasconcelos, C.

2017-12-01

The study of authigenic clay/carbonate-mineral associations within carbonate sequences has important implications for the interpretation of scientific problems related with rock reservoir properties, such as alteration of potential porosity and permeability. More specifically, when clay minerals are randomly distributed within the carbonate matrix, it becomes difficult to predict reservoir characteristics. In order to understand this mineral association in the geological record, we have undertaken a comparative study of specially designed laboratory experiments with modern environments, where clay minerals have been shown to precipitate together with a range of carbonate minerals, including calcite, Mg-calcite and dolomite. Two modern dolomite-forming environments, the Coorong lakes, South Australia and Brejo do Espinho Rio de Janeiro, Brazil, were selected for this investigation. For comparative evaluation, enrichment microbial culture experiments, using natural pore water from Brejo do Espinho as the growth medium to promote mineral precipitation, were performed under both aerobic and anaerobic conditions. To establish the environmental parameters and biological processes facilitating the dual mineral association, the experimental samples have been compared with the natural minerals using HRTEM measurements. The results demonstrate that the clay and carbonate minerals apparently do not co-precipitate, but the precipitation of the different minerals in the same sample has probably occurred under different environmental conditions with variable chemistries, e.g., hypersalinity versus normal salinity resulting from the changing ratio of evaporation versus precipitation. Thus, the investigated mineral association is not a product of diagenetic processes but of sequential in situ precipitation processes related to changes in the silica and carbon availability. Implications for ancient carbonate formations will be presented and discussed in the context of a specific example of this clay/carbonate-mineral association recorded in the Lower Cretaceous Codó Formation, NE Brazil (Bahniuk et al., 2015. Sedimentology, 62, 155-181).

Detecting a Difference in Clay Minerals at Two Gale Crater Sites

NASA Image and Video Library

2016-12-13

Data graphed here from the Chemistry and Camera (CheMin) instrument on NASA's Mars Curiosity rover show a difference between clay minerals in powder drilled from mudstone outcrops at two locations in Mars' Gale Crater: "Yellowknife Bay" and "Murray Buttes." CheMin's X-ray diffraction analysis reveals information about the crystalline structure of minerals in the rock. The intensity peaks marked with dotted vertical lines in this chart indicate that the crystalline structure of the two sites' clay minerals differs. The difference can be tied to a compositional difference in the clay minerals, as depicted in a diagram at PIA21148. The Yellowknife Bay site is on the floor of Gale Crater. The Murray Buttes site is on lower Mount Sharp, the layered mound in the center of the crater. http://photojournal.jpl.nasa.gov/catalog/PIA21147

Modelling of the physico-chemical behaviour of clay minerals with a thermo-kinetic model taking into account particles morphology in compacted material.

NASA Astrophysics Data System (ADS)

Sali, D.; Fritz, B.; Clément, C.; Michau, N.

2003-04-01

Modelling of fluid-mineral interactions is largely used in Earth Sciences studies to better understand the involved physicochemical processes and their long-term effect on the materials behaviour. Numerical models simplify the processes but try to preserve their main characteristics. Therefore the modelling results strongly depend on the data quality describing initial physicochemical conditions for rock materials, fluids and gases, and on the realistic way of processes representations. The current geo-chemical models do not well take into account rock porosity and permeability and the particle morphology of clay minerals. In compacted materials like those considered as barriers in waste repositories, low permeability rocks like mudstones or compacted powders will be used : they contain mainly fine particles and the geochemical models used for predicting their interactions with fluids tend to misjudge their surface areas, which are fundamental parameters in kinetic modelling. The purpose of this study was to improve how to take into account the particles morphology in the thermo-kinetic code KINDIS and the reactive transport code KIRMAT. A new function was integrated in these codes, considering the reaction surface area as a volume depending parameter and the calculated evolution of the mass balance in the system was coupled with the evolution of reactive surface areas. We made application exercises for numerical validation of these new versions of the codes and the results were compared with those of the pre-existing thermo-kinetic code KINDIS. Several points are highlighted. Taking into account reactive surface area evolution during simulation modifies the predicted mass transfers related to fluid-minerals interactions. Different secondary mineral phases are also observed during modelling. The evolution of the reactive surface parameter helps to solve the competition effects between different phases present in the system which are all able to fix the chemical elements mobilised by the water-minerals interaction processes. To validate our model we simulated the compacted bentonite (MX80) studied for engineered barriers for radioactive waste confinement and mainly composed of Na-Ca-montmorillonite. The study of particles morphology and reactive surfaces evolutions reveals that aqueous ions have a complex behaviour, especially when competitions between various mineral phases occur. In that case, our model predicts a preferential precipitation of finest particles, favouring smectites instead of zeolites. This work is a part of a PhD Thesis supported by Andra, the French Radioactive Waste Management Agency.

Bioremediation of PAHs and VOCs: Advances in clay mineral-microbial interaction.

PubMed

Biswas, Bhabananda; Sarkar, Binoy; Rusmin, Ruhaida; Naidu, Ravi

2015-12-01

Bioremediation is an effective strategy for cleaning up organic contaminants, such as polycyclic aromatic hydrocarbons (PAHs) and volatile organic compounds (VOCs). Advanced bioremediation implies that biotic agents are more efficient in degrading the contaminants completely. Bioremediation by microbial degradation is often employed and to make this process efficient, natural and cost-effective materials can serve as supportive matrices. Clay/modified clay minerals are effective adsorbents of PAHs/VOCs, and readily available substrate and habitat for microorganisms in the natural soil and sediment. However, the mechanism underpinning clay-mediated biodegradation of organic compounds is often unclear, and this requires critical investigation. This review describes the role of clay/modified clay minerals in hydrocarbon bioremediation through interaction with microbial agents in specific scenarios. The vision is on a faster, more efficient and cost-effective bioremediation technique using clay-based products. This review also proposes future research directions in the field of clay modulated microbial degradation of hydrocarbons. Copyright © 2015 Elsevier Ltd. All rights reserved.

Mineralogical Composition of Particle-Size Fractions of Solonetzes from the North Crimean Lowland

NASA Astrophysics Data System (ADS)

Chizhikova, N. P.; Khitrov, N. B.; Tronza, G. E.; Kol'tsov, S. A.; Varlamov, E. B.; Chechetko, E. S.; Churilin, N. A.

2017-12-01

Data on the mineralogical composition of clay (<1 μm), fine silt (1-5 μm), medium silt (5-10 μm), and coarser (>10 μm) fractions of meadow solonchakous solonetzes (Calcic Gypsic Salic Stagnic Solonetz (Albic, Siltic, Columnic, Cutanic, Differentic)) developing from loesslike loam and clay in the North Crimean Lowland are presented. Fractions >5 μm constitute nearly 50% of the soil mass and are characterized by the same mineralogical composition in the entire profile; they consist of quartz, plagioclases, potassium feldspars, and micas (biotite and muscovite). The eluvial-illuvial redistribution of clay in the course of solonetzic process is accompanied by changes in the portion of mixed-layer minerals and hydromicas in the upper part of the profile; a larger part of the smectitic phase is transformed into the superdisperse state. In the eluvial SEL horizon and in the illuvial BSN horizon, the clay fraction is impoverished in smectitic phase and enriched in trioctahedral hydromicas. Upon calculation of the content of clay minerals per bulk soil mass, the distribution of mixed-layer minerals is either eluvial, or eluvial-illuvial, whereas the distribution of hydromicas has an illuvial pattern without distinct eluvial minimum in the SEL horizons. The eluvial-illuvial distribution pattern of clay minerals in solonetzes of the North Crimean Lowland is compared with the distribution pattern of clay minerals in solonetzes of the West Siberian Lowland. Coefficients characterizing differentiation of solonetzes by the contents of particular mineral components are suggested.

Effect of Several Clay Minerals and Humic Acid on the Survival of Klebsiella aerogenes Exposed to Ultraviolet Irradiation1

PubMed Central

Bitton, Gabriel; Henis, Y.; Lahav, N.

1972-01-01

The effect of various clay minerals and humic acid on the survival of Klebsiella aerogenes exposed to ultraviolet (UV) irradiation was investigated. A protective effect was observed and found to depend on the specific light absorption and light scattering properties of the clay minerals and the humic acid used. The higher the specific absorption, the better was the survival of K. aerogenes after UV irradiation. Bacterial survival was lower in clays saturated with divalent cations (Ca, Zn) than in those homoionic to monovalent cations (K). PMID:5031559

Effect of organic matter properties, clay mineral type and thermal maturity on gas adsorption in organic-rich shale systems

USGS Publications Warehouse

Zhang, Tongwei; Ellis, Geoffrey S.; Ruppel, Stephen C.; Milliken, Kitty; Lewan, Mike; Sun, Xun; Baez, Luis; Beeney, Ken; Sonnenberg, Steve

2013-01-01

A series of CH4 adsorption experiments on natural organic-rich shales, isolated kerogen, clay-rich rocks, and artificially matured Woodford Shale samples were conducted under dry conditions. Our results indicate that physisorption is a dominant process for CH4 sorption, both on organic-rich shales and clay minerals. The Brunauer–Emmett–Teller (BET) surface area of the investigated samples is linearly correlated with the CH4 sorption capacity in both organic-rich shales and clay-rich rocks. The presence of organic matter is a primary control on gas adsorption in shale-gas systems, and the gas-sorption capacity is determined by total organic carbon (TOC) content, organic-matter type, and thermal maturity. A large number of nanopores, in the 2–50 nm size range, were created during organic-matter thermal decomposition, and they significantly contributed to the surface area. Consequently, methane-sorption capacity increases with increasing thermal maturity due to the presence of nanopores produced during organic-matter decomposition. Furthermore, CH4 sorption on clay minerals is mainly controlled by the type of clay mineral present. In terms of relative CH4 sorption capacity: montmorillonite ≫ illite – smectite mixed layer > kaolinite > chlorite > illite. The effect of rock properties (organic matter content, type, maturity, and clay minerals) on CH4 adsorption can be quantified with the heat of adsorption and the standard entropy, which are determined from adsorption isotherms at different temperatures. For clay-mineral rich rocks, the heat of adsorption (q) ranges from 9.4 to 16.6 kJ/mol. These values are considerably smaller than those for CH4 adsorption on kerogen (21.9–28 kJ/mol) and organic-rich shales (15.1–18.4 kJ/mol). The standard entropy (Δs°) ranges from -64.8 to -79.5 J/mol/K for clay minerals, -68.1 to -111.3 J/mol/K for kerogen, and -76.0 to -84.6 J/mol/K for organic-rich shales. The affinity of CH4 molecules for sorption on organic matter is stronger than for most common clay minerals. Thus, it is expected that CH4 molecules may preferentially occupy surface sites on organic matter. However, active sites on clay mineral surfaces are easily blocked by water. As a consequence, organic-rich shales possess a larger CH4-sorption capacity than clay-rich rocks lacking organic matter. The thermodynamic parameters obtained in this study can be incorporated into model predictions of the maximum Langmuir pressure and CH4- sorption capacity of shales under reservoir temperature and pressure conditions.

Arsenic(V) Removal in Wetland Filters Treating Drinking Water with Different Substrates and Plants.

PubMed

Wu, Min; Li, Qingyun; Tang, Xianqiang; Huang, Zhuo; Lin, Li; Scholz, Miklas

2014-05-01

Constructed wetlands are an attractive choice for removing arsenic (As) within water resources used for drinking water production. The role of substrate and vegetation in As removal processes is still poorly understood. In this study, gravel, zeolite (microporous aluminosilicate mineral), ceramsite (lightweight expanded clay aggregate) and manganese sand were tested as prospective substrates while aquatic Juncus effuses (Soft Rush or Common Rush) and terrestrial Pteris vittata L. (Chinese Ladder Brake; known as As hyperaccumulator) were tested as potential wetland plants. Indoor batch adsorption experiments combined with outdoor column experiments were conducted to assess the As removal performances and process mechanisms. Batch adsorption results indicated that manganese sand had the maximum As(V) adsorption rate of 4.55 h -1 and an adsorption capacity of 42.37 μg/g compared to the other three aggregates. The adsorption process followed the pseudo-first-order kinetic model and Freundlich isotherm equations better than other kinetic and isotherm models. Film-diffusion was the rate-limiting step. Mean adsorption energy calculation results indicated that chemical forces, particle diffusion and physical processes dominated As adsorption to manganese sand, zeolite and gravel, respectively. During the whole running period, manganese sand-packed wetland filters were associated with constantly 90% higher As(V) reduction of approximate 500 μg/L influent loads regardless if planted or not. The presence of P. vittata contributed to no more than 13.5% of the total As removal. In contrast, J. effuses was associated with a 24% As removal efficiency.

Building zeolites from pre-crystallized units: nanoscale architecture.

PubMed

Corma, Avelino; Li, Chengeng; Moliner, Manuel

2018-01-24

Since the earlier descriptions by Barrer in the 40's on converting natural minerals into synthetic zeolites, the use of pre-crystallized zeolites as crucial inorganic directing agents to synthesize other crystalline zeolites with improved physico-chemical properties, has become a very intense and relevant research field, allowing the design, particularly in the last years, of new industrial catalysts. In the present review, we will highlight how the presence of some crystalline fragments in the synthesis media, such as small secondary building units (SBUs) or layered substructures, not only favors the crystallization of other zeolites presenting similar SBUs or layers, but also permits mostly controlling important parameters affecting to their catalytic activity (i.e. chemical composition, crystal size, or porosity, among others). In this sense, the recent advances on the preparation of 3-D and 2-D related zeolites through seeding and zeolite-to-zeolite transformation processes will be extensively revised, including their preparation in presence or absence of organic structure directing agents (OSDAs), with the aim of introducing general guidelines for designing more efficient future synthesis approaches for target zeolites. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Antimony(V) Adsorption by Variable-Charge Minerals

DTIC Science & Technology

2013-10-01

6‒] and inner-sphere [≡SOSb(OH)5‒] adsorption mechanisms. In general, however, the models generated for single ligand systems required reoptimization...HCO3 and CO3 ) effectively desorbed Sb(V) from hydrous metal (Al and Fe) oxides, clay minerals, and Sb(V)-contaminated sediments, relative to the...temperatures (20- 22°C). 7 A well- crystallized Georgia kaolinite (KGa-1b) from the Source Clays Repository of The Clay Minerals Society (West Lafayette

State summaries: Kentucky

USGS Publications Warehouse

Greb, S.F.; Anderson, W.H.

2006-01-01

Kentucky mines coal, limestone, clay, sand and gravel. Coal mining operations are carried out mainly in the Western Kentucky Coal Field and the Eastern Kentucky Coal field. As to nonfuel minerals, Mississippian limestones are mined in the Mississippian Plateaus Region and along Pine Mountain in southeastern Kentucky. Ordovician and Silurian limestones are mined from the central part of the state. Clay minerals that are mined in the state include common clay, ceramic and ball clays, refractory clay and shale. Just like in 2004, mining activities in the state remain significant.

Clay fractions from a soil chronosequence after glacier retreat reveal the initial evolution of organo-mineral associations

NASA Astrophysics Data System (ADS)

Dümig, Alexander; Häusler, Werner; Steffens, Markus; Kögel-Knabner, Ingrid

2012-05-01

Interactions between organic and mineral constituents prolong the residence time of organic matter in soils. However, the structural organization and mechanisms of organic coverage on mineral surfaces as well as their development with time are still unclear. We used clay fractions from a soil chronosequence (15, 75 and 120 years) in the foreland of the retreating Damma glacier (Switzerland) and from mature soils outside the proglacial area (>700 and <3000 years) to elucidate the evolution of organo-mineral associations during initial soil formation. The chemical composition of the clay-bound organic matter (OM) was assessed by solid-state 13C NMR spectroscopy while the quantities of amino acids and neutral sugar monomers were determined after acid hydrolysis. The mineral phase was characterized by X-ray diffraction, oxalate extraction, specific surface area by N2 adsorption (BET approach), and cation exchange capacity at pH 7 (CECpH7). The last two methods were applied before and after H2O2 treatment. We found pronounced shifts in quantity and quality of OM during aging of the clay fractions, especially within the first one hundred years of soil formation. The strongly increasing organic carbon (OC) loading of clay-sized particles resulted in decreasing specific surface areas (SSA) of the mineral phases and increasing CECpH7. Thus, OC accumulation was faster than the supply of mineral surfaces and cation exchange capacity was mainly determined by the OC content. Clay-bound OC of the 15-year-old soils showed high proportions of carboxyl C and aromatic C. This may point to remnants of ancient OC which were inherited from the recently exposed glacial till. With increasing age (75 and 120 years), the relative proportions of carboxyl and aromatic C decreased. This was associated with increasing O-alkyl C proportions, whereas accumulation of alkyl C was mainly detected in clay fractions from the mature soils. These findings from solid-state 13C NMR spectroscopy are in line with the increasing amounts of microbial-derived carbohydrates with soil age. The large accumulation of proteins, which was comparable to those of carbohydrates, and the very low C/N ratios of H2O2-resistant OM indicated strong and preferential associations between proteinaceous compounds and mineral surfaces. In the acid soils, poorly crystalline Fe oxides were the main providers of mineral surface area and important for the stabilization of OM during aging of the clay fractions. This was indicated by (I) the strong correlations between oxalate soluble Fe and both, SSA of H2O2-treated clay fractions and OC content, and (II) the low formation of expandable clays due to small extents of mineral weathering. Our chronosequence approach provided new insights into the evolution of organo-mineral interactions in acid soils. The formation of organo-mineral associations started with the sorption of proteinaceous compounds and microbial-derived carbohydrates on mineral surfaces which were mainly provided by ferrihydrite. The sequential accumulation of different organic compounds and the large OC loadings point to multiple accretion of OM in distinct zones or layers during the initial evolution of clay fractions.

Overview of the evolution of clay mineralogy in the Gulf of Mexico: implications for regional climate and drainage history of the Mississippi and Brazos-Trinity Rivers

NASA Astrophysics Data System (ADS)

Adatte, T.; John, C. M.; Flemings, P. B.; Behrmann, J.

2005-12-01

In this paper we present the overview and preliminary results of the analysis of clay minerals in two mini basins drilled during IODP Expedition 308. The goal of our project is to explore the vertical and temporal trends in clay mineralogy in the Ursa Basin and the Brazos-Trinity basin #4. The Brazos-Trinity basin was the sink for sands and clays carried by the Brazos and Trinity Rivers, while the Ursa basin was the sink for sediments carried by the Mississippi river. Reconstructing clay minerals (phyllosilicates <2μm in size) accumulations at these locations could thus potentially yield information on changes in the transport and the source of the siliclastic material transported in the course of the Pleistocene by these three rivers. Moreover, because the type of clay formed in soils through weathering processes largely depend on temperature and amount of precipitation, the dataset generated could provide clues on past climate changes. Some of the mechanisms that are hypothesized to play a major role in controlling clay accumulation in the basins investigated are reworking of clays on the American continent (controlled at the time-scale investigated here by changes in precipitation) and turbidity current deposition (controlled mainly by sea-level changes and thus glacio-eustasy). Finally, a major focusing point of Expedition 308 was sediment physical properties in an overpressured basin. Because each clay mineral specie has a specific average grain sizes, physical properties and cation exchange capacity, the clay mineral composition of the sediment investigated here (dominated by clay-sized particles) may partly control how these sediments react to changes in pressure and temperature. Thus, clay mineral data could contribute to our understanding of the physical properties of the sediments in overpressured basins, and collaborations with geotechnical scientist are planned.

Superficial alteration mineralogy in active volcanic systems: An example of Poás volcano, Costa Rica

NASA Astrophysics Data System (ADS)

Rodríguez, Alejandro; van Bergen, Manfred J.

2017-10-01

The alteration mineralogy in the crater area of Poás volcano (Costa Rica) has been studied to constrain acid fluid-rock interaction processes and conditions relevant for the formation of sulphate-bearing mineral assemblages found on the surface of Mars. Individual sub-environments, which include the hyperacid lake (Laguna Caliente), ephemeral hot springs, fumarole vents and areas affected by acid rain and/or spray from the lake, are marked by distinct secondary mineral associations, with sulphates commonly as prevailing component. The sulphates occur in a wide mineralogical diversity comprising gypsum/anhydrite, various polyhydrated Al-sulphates, alunite-jarosite group minerals, halotrichite-, voltaite- and copiapite-group minerals, epsomite and römerite. Depending on the sub-environment, they are variably associated with clay minerals (kaolinite-group and smectite-group), zeolites, SiO2-polymorphs, Fe-(hydro)oxides, Ti-oxides, native sulphur, sulphides, chlorides, fluorides, phosphates and carbonates. Geochemical modelling was performed to identify mechanisms responsible for the formation of the secondary minerals found in the field, and to predict their possible stability under conditions not seen at the surface. The results indicate that the appearance of amorphous silica, hematite, anhydrite/gypsum, pyrite, anatase and kaolinite is relatively insensitive to the degree of acidity of the local aqueous system. On the other hand, alunite-jarosite group minerals, elemental sulphur and Al(OH)SO4 only form under acidic conditions (pH < 4). The presence of polyhydrated Mg- and Fe2 +-sulphates is restricted to olivine-bearing rocks exposed to acid rain or brine spray. Modelling suggests that their formation required a repetitive sequence of olivine dissolution and evaporation in an open system involving limited amounts of fluid. The mineral variety in the crater of Poás is remarkably similar to sulphate-bearing assemblages considered to be the product of acid-sulphate alteration on Mars. The analogy suggests that comparable fluid-rock interaction controls operated in Martian volcanic environments.

Mineralogy and sedimentology of the Miocene Göcenoluk borate deposit, Kırka district, western Anatolia, Turkey

NASA Astrophysics Data System (ADS)

García-Veigas, Javier; Helvacı, Cahit

2013-05-01

The Miocene boratiferous district of Kırka, in western Anatolia (Turkey), is the most important Na-borate (borax) resource in the world. Two separate deposits in the Kırka district are located near the villages of Sarıkaya and Göcenoluk (Eskişehir Province). Borax is intensively exploited in open-pit mines in the Sarıkaya deposit while only small quarries of colemanite are known in the Göcenoluk deposit. Recent exploratory drilling in the Göcenoluk area intersected a thick succession of dolostones, tuffs and three borate-bearing units (Lower, Intermediate and Upper Borate Units). In them, the most abundant borate mineral is ulexite (Ca-Na-borate) passing at depth to probertite. Borax (Na-borate) is only present in the Intermediate Borate Unit. Minor amounts of colemanite (Ca-borate) and hydroboracite (Ca-Mg-borate) occur at the base, and/or top, of each mineralized unit. Pyroclastic layers within the borate units show intense alteration by alkaline, boron-bearing waters and formation of diagenetic clay minerals (smectites), zeolites (analcime) and borosilicates (searlesite). The Göcenoluk succession is interpreted as a shallow, ephemeral, alkaline lake deposit in which carbonates formed as stromatolites and travertines. Borate precipitation in the Göcenoluk area took place interstitially within muddy and carbonate sediments in a lateral progression from marginal Ca-borates towards Na-Ca-borates and rarely to Na-borates in the center of the lake. Authigenic silicate mineral distribution shows parallel changes toward the center of the lake that reflect increasing pH gradient.

Chemical effects of carbon dioxide sequestration in the Upper Morrow Sandstone in the Farnsworth, Texas, hydrocarbon unit

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ahmmed, Bulbul; Appold, Martin S.; Fan, Tianguang

Numerical geochemical modeling was used to study the effects on pore-water composition and mineralogy from carbon dioxide (CO2) injection into the Pennsylvanian Morrow B Sandstone in the Farnsworth Unit in northern Texas to evaluate its potential for long-term CO2 sequestration. Speciation modeling showed the present Morrow B formation water to be supersaturated with respect to an assemblage of zeolite, clay, carbonate, mica, and aluminum hydroxide minerals and quartz. The principal accessory minerals in the Morrow B, feldspars and chlorite, were predicted to dissolve. A reaction-path model in which CO2 was progressively added up to its solubility limit into the Morrowmore » B formation water showed a decrease in pH from its initial value of 7 to approximately 4.1 to 4.2, accompanied by the precipitation of small amounts of quartz, diaspore, and witherite. As the resultant CO2-charged fluid reacted with more of the Morrow B mineral matrix, the model predicted a rise in pH, reaching a maximum of 5.1 to 5.2 at a water–rock ratio of 10:1. At a higher water–rock ratio of 100:1, the pH rose to only 4.6 to 4.7. Diaspore, quartz, and nontronite precipitated consistently regardless of the water–rock ratio, but the carbonate minerals siderite, witherite, dolomite, and calcite precipitated at higher pH values only. As a result, CO2 sequestration by mineral trapping was predicted to be important only at low water–rock ratios, accounting for a maximum of 2% of the added CO2 at the lowest water–rock ratio investigated of 10:1, which corresponds to a small porosity increase of approximately 0.14% to 0.15%.« less

Exploring biotic vs. abiotic controls on syngenetic carbonate and clay mineral precipitation

NASA Astrophysics Data System (ADS)

Nascimento, Gabriela S.; McKenzie, Judith A.; Martinez Ruiz, Francisca; Bontognali, Tomaso R. R.; Vasconcelos, Crisogono

2016-04-01

A possible syngenetic relationship between carbonate and clay mineral precipitation has been reported for sedimentary rocks deposited in both lacustrine and marine sedimentary environments throughout the geological record. In particular, the mineral dolomite is often found associated with Mg-rich clays, such as stevensite. It is notable that this carbonate/clay association has been recorded in numerous samples taken from modern dolomite precipitating environments; for example, the Coorong lakes, South Australia, coastal sabkhas, Abu Dhabi, UAE and coastal hypersaline lagoons (Lagoa Vermelha and Brejo do Espinho) east of Rio de Janeiro, Brazil. An HRTEM study of samples from these three locations indicates a possible physical/chemical association between the Ca-dolomite and Mg-rich clays, demonstrating a probable co-precipitation. To test this hypothesis, we have conducted a series of biotic and abiotic laboratory experiments. If this syngenesis actually occurs in nature, what, if any, are the biogeochemical processes controlling these precipitation reactions? Our experiments were designed to determine the extent of the biotic versus abiotic component influencing the mineral precipitation and, in the case of a biotic influence, to understand the mechanism through which microorganisms might mediate the formation of clay minerals. The experiments were carried out in the Geomicrobiology Laboratory of ETH Zürich using cultures of living microbes and artificial organic compounds that simulate functional groups present in natural biofilms formed under both aerobic and anaerobic conditions. In addition, pure inorganic experiments were designed to understand possible physico-chemical conditions for diagenetic processes that could induce dissolution of Mg-carbonates and precipitation of Mg-rich clays. Our results show a remarkable biotic influence during the formation of clay minerals. Specifically, extracellular polymeric substances (EPS), released by microbes in their surrounding environments, appear to play a key role in the mineralization process, by binding and concentrating silica and by stabilizing cations in specific co-ordination positions. This step may be essential for the initial nucleation of the clay mineral. Also, the conditions of the biotic experiments probably helped to lower kinetic barriers and promote the reactions, which apparently remained kinetically constrained in the abiotic experiments. These initial experimental results provide information to understand the syngenetic relationship between dolomite and Mg-rich clay precipitation and furnish additional information to help reconstruct paleoenviromental conditions for similar deposits found in the geological record.

Synthesis of hectorite-TiO2 and kaolinite-TiO2 nanocomposites with photocatalytic activity for the degradation of model air pollutants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Destaillats, Hugo; Kibanova, D.; Trejo, M.

2008-03-01

We studied the synthesis and photocatalytic activity of small-sized TiO{sub 2} supported on hectorite and kaolinite. Deposition of TiO{sub 2} on the clay mineral surface was conducted by using a sol-gel method with titanium isopropoxide as precursor. Anatase TiO{sub 2} particles formation was achieved by hydrothermal treatment at 180 C. Material characterization was conducted using XRD, SEM, XPS, ICP-OES, BET and porosimetry analysis. Efficiency in synthesizing clay-TiO{sub 2} composites depended strongly on the clay mineral structure. Incorporation of anatase in hectorite, an expandable clay mineral, was found to be very significant (> 36 wt.% Ti) and to be followed bymore » important structural changes at the clay mineral surface. Instead, no major structural modifications of the clay were observed for kaolinite-TiO{sub 2}, as compared with the untreated material. Photocatalytic performance of clay-TiO{sub 2} composites was evaluated with ATR-FTIR following the oxidation of adsorbed toluene and d-limonene, two model air pollutants. In either case, the photocatalytic removal efficiency of these hydrophobic substrates by the synthesized clay-TiO{sub 2} composites was comparable to that observed using pure commercial TiO{sub 2} (Degussa P25).« less

Mineral resources of Novokuznetsk administrative district of Kemerovo region (metallic and non-metallic minerals)

NASA Astrophysics Data System (ADS)

Gutak, Ja M.

2017-09-01

The article summarizes data on metallic and non-metallic minerals of Novokuznetsk district of Kemerovo region. Consistently reviewed are iron deposits (Tersinskaya group of deposits), gold deposits (placer accumulations and vein gold deposits), mineral water deposits (Tersinskoe deposit), deposit of refractory clay (Barkinskoe) and wide spread mineral deposits such as brick clay, keramzite materials, sand and gravel, building stones, ornamental stones, facing stones, peat, materials for lime production. It is indicated that resource base of metallic and nonmetallic minerals is inferior to that of mineral coal. At the same time it can be of considerable interest to small and medium-size businesses as objects with quick return of investment (facing and ornamental stones). For a number of wide spread mineral resources (brick clay, keramzite materials, sand and gravel) it is an important component of local industry.

Hydrogeologic investigations of the Miocene Nogales Formation in the Nogales Area, Upper Santa Cruz Basin, Arizona

USGS Publications Warehouse

Page, William R.; Gray, Floyd; Bultman, Mark W.; Menges, Christopher M.

2016-07-28

Hydrogeologic investigations were conducted to evaluate the groundwater resource potential for the Miocene Nogales Formation in the Nogales area, southern Arizona. Results indicate that parts of the formation may provide new, deeper sources of groundwater for the area. Geologic mapping determined the hydrogeologic framework of the formation by defining lithologic, mineralogic, and stratigraphic characteristics; identifying potential aquifers and confining units; and mapping faults and fractures which likely influence groundwater flow. Geophysical modeling was used to determine the basin geometry and thickness of the Nogales Formation and younger alluvial aquifers and to identify target areas (deep subbasins) which may prove to be productive aquifers.Volcaniclastic sandstone samples from the formation were analyzed for porosity, bulk density, saturated hydraulic conductivity, and fabric. Effective porosity ranges from 16 to 42 percent, bulk density from 1.6 to 2.47 grams per cubic centimeter, and saturated hydraulic conductivity (SHC) from 4 to 57 centimeters per day (4.9×10-5 to 6.7×10-4 centimeters per second). Thin sections show that sandstone framework grains consist of quartz, feldspar, biotite, hornblende, pumice, volcanic glass, and opaque minerals. The matrix in most samples consists of pumice fragments, and some contain predominantly silt and clay. Samples with a mostly silt and clay matrix have lower porosity and SHC compared to samples with mostly pumice, which have higher and wider ranges of porosity and SHC. Pore space in the Nogales Formation sediments includes moldic, intercrystalline, and fracture porosity. Some intercrystalline pore space is partially filled with calcite cement. About one third of the samples contain fractures, which correspond to fractures noted in outcrops in all members of the formation.Scanning electron microscope (SEM) and x-ray diffraction (XRD) analyses indicate that most of the samples contained the zeolite clinoptilolite and mixed-layer clay. X-ray diffraction analyses verified clinoptilolite as the only zeolite in Nogales Formation samples; they also verified the presence of smectite and illite clay and some kaolinite. Samples which contain greater amounts of clinoptilolite and lesser amounts of smectite have high porosity and SHC in narrow ranges. However, samples with abundant smectite and lesser amounts of clinoptilolite span the entire ranges of porosity and SHC for the formation.All members of the Nogales Formation are fractured and faulted as a result of Tertiary Basin and Range extensional deformation, which was broadly contemporaneous with deposition of the formation. These structures may have significant influence on groundwater flow in the upper Santa Cruz basin because, although many of the sediments in the formation have characteristics indicating they may be productive aquifers based only on porous-media flow, fracturing in these sediments may further enhance permeability and groundwater flow in these basin-fill aquifers by orders of magnitude.

Continental weathering as a driver of Late Cretaceous cooling: new insights from clay mineralogy of Campanian sediments from the southern Tethyan margin to the Boreal realm

NASA Astrophysics Data System (ADS)

Chenot, Elise; Deconinck, Jean-François; Pucéat, Emmanuelle; Pellenard, Pierre; Guiraud, Michel; Jaubert, Maxime; Jarvis, Ian; Thibault, Nicolas; Cocquerez, Théophile; Bruneau, Ludovic; Razmjooei, Mohammad J.; Boussaha, Myriam; Richard, James; Sizun, Jean-Pierre; Stemmerik, Lars

2018-03-01

New clay mineralogical analyses have been performed on Campanian sediments from the Tethyan and Boreal realms along a palaeolatitudinal transect from 45° to 20°N (Danish Basin, North Sea, Paris Basin, Mons Basin, Aquitaine Basin, Umbria-Marche Basin and Tunisian Atlas). Significant terrigenous inputs are evidenced by increasing proportions of detrital clay minerals such as illite, kaolinite and chlorite at various levels in the mid- to upper Campanian, while smectitic minerals predominate and represented the background of the Late Cretaceous clay sedimentation. Our new results highlight a distinct latitudinal distribution of clay minerals, with the occurrence of kaolinite in southern sections and an almost total absence of this mineral in northern areas. This latitudinal trend points to an at least partial climatic control on clay mineral sedimentation, with a humid zone developed between 20° and 35°N. The association and co-evolution of illite, chlorite and kaolinite in most sections suggest a reworking of these minerals from basement rocks weathered by hydrolysis, which we link to the formation of relief around the Tethys due to compression associated with incipient Tethyan closure. Diachronism in the occurrence of detrital minerals between sections, with detrital input starting earlier during the Santonian in the south than in the north, highlights the northward progression of the deformation related to the anticlockwise rotation of Africa. Increasing continental weathering and erosion, evidenced by our clay mineralogical data through the Campanian, may have resulted in enhanced CO2 consumption by silicate weathering, thereby contributing to Late Cretaceous climatic cooling.

Surveying Clay Mineral Diversity in the Murray Formation, Gale Crater, Mars

NASA Technical Reports Server (NTRS)

Bristow, T.F.; Blake, D. F..; Vaniman, D. T.; Chipera, S. J.; Rampe, E. B.; Grotzinger, J. P.; McAdam, A. C.; Ming, D. W..; Morrison, S. M.; Yen, A. S.;

The Impact of Mass Movement and Fluid Flow during Ridge Subduction inferred from Physical Properties and Zeolite Assemblage in the Upper Plate Slope of the Costa Rica Subduction Zone

NASA Astrophysics Data System (ADS)

Hamahashi, M.; Screaton, E.; Tanikawa, W.; Hashimoto, Y.; Martin, K. M.; Saito, S.; Kimura, G.

2015-12-01

The Costa Rica subduction zone offshore Osa Peninsula is known as an erosive margin with active seismicity and the subduction of the Cocos Ridge. One of the major unknowns in this margin is the nature of the unconformity at the base of the slope sediments in the upper plate and the high velocity materials below. To investigate the geologic processes across the unconformity, we examined the consolidation state and mineral assemblages of the sediments at the mid-slope Site 1380 drilled during IODP Expedition 344 by conducting microstructural observation, particle size analysis, X-ray fluorescence/diffraction analysis and resistivity measurement. The general compaction trend is controlled primarily by grain-size sorting and the physical property transition is likely caused by massive sediment removal under normal fault regime, thickness of which range between ~600-850 m determined from the composite porosity-depth curve. Across the unconformity between the late Pliocene~late Pleistocene silty clay (Unit 1) and late Pliocene~early Pleistocene clayey siltstone (Unit 2), the mineral/element components of the sediments is marked by the transitions in zeolite compositions; Unit 1 consists of laumontite and heulandite, whereas below the unconformity, Unit 2 sediments contain analcime, laumontite, and heulandite, but laumontite become less abundant at lower depth. The experienced temperature of the sediments in Unit 2 is estimated to have reached between ~86 and 122℃ as inferred from analcime burial diagenesis. This may correspond with the greater depth range prior to mass movement and normal faulting. The initial analcime burial diagenetic zone was likely cut off by the sediment removal across the unconformity, and later overprinted by high temperature fluid along the boundary forming laumontite and heulandite in the vicinity. These results illustrate that ridge subduction has substantial potential to cause mass movement, an extensional stress regime, and fluid flow from depth.

Nontronite and Montmorillonite as Nutrient Sources for Life on Mars

NASA Technical Reports Server (NTRS)

Craig, P. I.; Mickol, R. L.; Archer, P. D.; Kral, T. A.

2017-01-01

Clay minerals have been identified on Mars' oldest (Noachian) terrain and their presence suggests long-term water-rock interactions. The most commonly identified clay minerals on Mars to date are nontronite (Fe-smectite) and montmorillonite (Al-smectite) [1], both of which contain variable amounts of water both adsorbed on their surface and within their structural layers. Over Mars' history, these clay miner-al-water assemblages may have served as nutrient sources for microbial life.

Mapping of hydrothermally altered rocks using airborne multispectral scanner data, Marysvale, Utah, mining district

USGS Publications Warehouse

Podwysocki, M.H.; Segal, D.B.; Jones, O.D.

1983-01-01

Multispectral data covering an area near Marysvale, Utah, collected with the airborne National Aeronautics and Space Administration (NASA) 24-channel Bendix multispectral scanner, were analyzed to detect areas of hydrothermally altered, potentially mineralized rocks. Spectral bands were selected for analysis that approximate those of the Landsat 4 Thematic Mapper and which are diagnostic of the presence of hydrothermally derived products. Hydrothermally altered rocks, particularly volcanic rocks affected by solutions rich in sulfuric acid, are commonly characterized by concentrations of argillic minerals such as alunite and kaolinite. These minerals are important for identifying hydrothermally altered rocks in multispectral images because they have intense absorption bands centered near a wavelength of 2.2 ??m. Unaltered volcanic rocks commonly do not contain these minerals and hence do not have the absorption bands. A color-composite image was constructed using the following spectral band ratios: 1.6??m/2.2??m, 1.6??m/0.48??m, and 0.67??m/1.0??m. The particular bands were chosen to emphasize the spectral contrasts that exist for argillic versus non-argillic rocks, limonitic versus nonlimonitic rocks, and rocks versus vegetation, respectively. The color-ratio composite successfully distinguished most types of altered rocks from unaltered rocks. Some previously unrecognized areas of hydrothermal alteration were mapped. The altered rocks included those having high alunite and/or kaolinite content, siliceous rocks containing some kaolinite, and ash-fall tuffs containing zeolitic minerals. The color-ratio-composite image allowed further division of these rocks into limonitic and nonlimonitic phases. The image did not allow separation of highly siliceous or hematitically altered rocks containing no clays or alunite from unaltered rocks. A color-coded density slice image of the 1.6??m/2.2??m band ratio allowed further discrimination among the altered units. Areas containing zeolites and some ash-fall tuffs containing montmorillonite were readily recognized on the color-coded density slice as having less intense 2.2-??m absorption than areas of highly altered rocks. The areas of most intense absorption, as depicted in the color-coded density slice, are dominated by highly altered rocks containing large amounts of alunite and kaolinite. These areas form an annulus, approximately 10 km in diameter, which surrounds a quartz monzonite intrusive body of Miocene age. The patterns of most intense alteration are interpreted as the remnants of paleohydrothermal convective cells set into motion during the emplacement of the central intrusive body. ?? 1983.

Spatially resolved nanoscale observations of soil carbon multidecadal persistence

NASA Astrophysics Data System (ADS)

Lutfalla, S.; Chenu, C.; Bernard, S.; Le Guillou, C.; Barré, P.

2015-12-01

Assessing how mineral surfaces, especially at small scale, can protect soil organic carbon (SOC) from biodegradation is crucial. The question we address in this work is whether different mineral species lead to different organo-mineral interactions and stabilize different quantities of SOM and different types of SOC. Here we used the unique opportunity offered by long term bare fallows (BF) to study in situ C dynamics in several fine fractions of a silty loam soil. With no vegetation i.e. no external input of fresh C, the plant-free soil of the Versailles 42 Plots (INRA, France) has been progressively enriched in persistent SOC during the 80 years of BF. Contrasted mineral phases of the clay size fraction were isolated by size fractionation on samples from 5 different dates (0, 10, 22, 52, and 79 years after the beginning of the BF, four field replicates per date). Four fractions were studied: total clays (< 2 μm), and three sub fractions in the clay (fine clay: 0 - 0.05 μm, intermediate clay: 0.05 - 0.2 μm, and coarse clay: 0.2 - 2 μm). X-ray diffraction analyses showed contrasted mineralogies in the fine and intermediate clay (smectite and mixed layered illite/smectite) as opposed to the coarse clay (smectite, illite, kaolinite and mixed layered I/S). We performed CHN elemental analysis and synchrotron based spectroscopy and microscopy (NEXAFS bulk and STXM at the carbon K edge of 280 eV, CLS Saskatoon, Canada) to study the dynamics, the distribution and the chemical speciation of the SOC in these fractions. The quantity of C appears to be stabilized after 50 years of BF, even though the dynamics are different for the three clay fractions. Indeed, coarse and intermediate clays have the same final C content but coarse clays lose more C. Fine clay experiences the highest C losses and displays the highest final C content suggesting that fine clays contained more labile C and more persistent C. In all fractions, C:N ratios are really low (below 8) and are decreasing with time, evidencing the dominant presence of microbial SOC. STXM-NEXAFS data shows that, in the fine and intermediate clay fractions, during the first 50 years of BF all mineral particles are associated with SOC. On the contrary, in the coarse clays, SOC displays more diversity: the chemical signature is more diverse and mineral particles not associated with SOC appear more quickly.

Mineralogy and Geochemistry of the Main Glauconite Bed in the Middle Eocene of Texas: Paleoenvironmental Implications for the Verdine Facies

PubMed Central

Harding, Sherie C.; Nash, Barbara P.; Petersen, Erich U.; Ekdale, A. A.; Bradbury, Christopher D.; Dyar, M. Darby

2014-01-01

The Main Glauconite Bed (MGB) is a pelleted greensand located at Stone City Bluff on the south bank of the Brazos River in Burleson County, Texas. It was deposited during the Middle Eocene regional transgression on the Texas Gulf Coastal Plain. Stratigraphically it lies in the upper Stone City Member, Crockett Formation, Claiborne Group. Its mineralogy and geochemistry were examined in detail, and verdine facies minerals, predominantly odinite, were identified. Few glauconitic minerals were found in the green pelleted sediments of the MGB. Without detailed mineralogical work, glaucony facies minerals and verdine facies minerals are easily mistaken for one another. Their distinction has value in assessing paleoenvironments. In this study, several analytical techniques were employed to assess the mineralogy. X-ray diffraction of oriented and un-oriented clay samples indicated a clay mixture dominated by 7 and 14Å diffraction peaks. Unit cell calculations from XRD data for MGB pellets match the odinite-1M data base. Electron microprobe analyses (EMPA) from the average of 31 data points from clay pellets accompanied with Mössbauer analyses were used to calculate the structural formula which is that of odinite: Fe3+ 0.89 Mg0.45 Al0.67 Fe2+ 0.30 Ti0.01 Mn0.01) Σ = 2.33 (Si1.77 Al0.23) O5.00 (OH)4.00. QEMSCAN (Quantitative Evaluation of Minerals by Scanning Electron Microscopy) data provided mineral maps of quantitative proportions of the constituent clays. The verdine facies is a clay mineral facies associated with shallow marine shelf and lagoonal environments at tropical latitudes with iron influx from nearby runoff. Its depositional environment is well documented in modern nearshore locations. Recognition of verdine facies clays as the dominant constituent of the MGB clay pellets, rather than glaucony facies clays, allows for a more precise assessment of paleoenvironmental conditions. PMID:24503875

An abiogenic photochemical synthesis on surface of meteorites and other small space bodies

NASA Astrophysics Data System (ADS)

Simakov, M.; Kuzicheva, E.

Abiogenic photochemical synthesis of complex biochemical compounds on the surface of small bodies in our Solar system was examined. The hydrated minerals are found within a chondrite matrix of meteorites together with significant amounts of organic matter. Clays are likely to have formed when water was presented on parent meteoritic bodies. In order to verify the existence of a relationship between abiogenic synthesis of nucleotides and inorganic components of the meteorites we have investigated possible abiogenic reactions at the presence of different clay minerals (montmorillonite, kaolinite) and basaltic sample (Tjatja's volcanic ash) under action of open space energy sources for modeling of different exobiological environments on the surface of small space bodies. The abiogenic synthesis of natural adenine nucleotides from mixture of adenosine plus inorganic phosphate has been observed under an irradiation with VUV radiation at the presence of different mineral samples. The yields of the products (5'AMP, 2'AMP, 3'AMP, 2'3'cAMP and 3'5'cAMP) were depended from irradiation time and kind of used minerals. The discovery that meteoritic organic compounds may be trapped and protected within a clay mineral matrix has implications for our understanding of prebiotic molecular evolution in the early Solar system. Clay minerals may have concentrated organic compounds thereby promoting polymerization reactions also. An adsorption/binding of nucleic acids components by clay crystals could change in the electron distribution and/or the conformation of the molecules. The remnant water molecules in the clay sheets also could influence on the course of the reaction. Besides, an immobilization of phosphate on clay also could play an important role in our reaction. Chondritic material would have been a common component of the inner Solar system shortly after its formation and the biologically useful products of clay mineral-organic matter interactions would have also widespread, and delivered to planetary surfaces through the accretion of carbonaceous asteroids.

Geological and technological characterization of the Late Jurassic-Early Cretaceous clay deposits (Jebel Ammar, northeastern Tunisia) for ceramic industry

NASA Astrophysics Data System (ADS)

Ben M'barek-Jemaï, Moufida; Sdiri, Ali; Ben Salah, Imed; Ben Aissa, Lassaad; Bouaziz, Samir; Duplay, Joelle

2017-05-01

Late Jurassic-Lower Cretaceous clays of the Jebel Ammar study site were used as raw materials for potential applications in ceramic industry. Physico-chemical characterization of the collected samples was performed using atomic absorption spectroscopy, X-ray diffraction, thermogravimetry and dilatometry (Bugot's curve). Geotechnical study was also undertaken by the assessment of plasticity and liquidity limits. It was found that high concentrations of silica, alumina with SiO2/Al2O3 ratio characterized the studied clays; its high amounts of CaO and Fe2O3 in the Late Jurassic clays indicated their calcareous nature. In addition, technological tests indicated moderate to low plasticity values for the Late Jurassic and Lower Cretaceous clays, respectively. Clay fraction (<2 μm) reached 50% of the natural clay in some cases. Mineralogical analysis showed that Jurassic clays were dominated by smectite, illite and kaolinite, as clay mineral species; calcite was the main associated mineral. Lower Cretaceous clays were mainly composed of abundant illite accompanied by well-crystallized smectite and kaolinite. Kaolinite gradually increased upwards, reaching 70% of the total clay fraction (i.e. <2 μm). Quartz, calcite and feldspar were the main non-clay minerals. Based on these analyses, the clays meet technological requirements that would allow their use in the ceramic industry and for the manufacturing of ceramic tiles.

Preparation of highly ordered cubic NaA zeolite from halloysite mineral for adsorption of ammonium ions.

PubMed

Zhao, Yafei; Zhang, Bing; Zhang, Xiang; Wang, Jinhua; Liu, Jindun; Chen, Rongfeng

2010-06-15

Well-ordered cubic NaA zeolite was first synthesized using natural halloysite mineral with nanotubular structure as source material by hydro-thermal method. SEM and HRTEM images indicate that the synthesized NaA zeolite is cubic-shaped crystal with planar surface, well-defined edges and symmetrical and uniform pore channels. The adsorption behavior of ammonium ions (NH(4)(+)) from aqueous solution onto NaA zeolite was investigated as a function of parameters such as equilibrium time, pH, initial NH(4)(+) concentration, temperature and competitive cations. The Langmuir and Freundlich adsorption models were applied to describe the equilibrium isotherms. A maximum adsorption capacity of 44.3 mg g(-1) of NH(4)(+) was achieved. The regeneration and reusable ability of this adsorbent was evaluated, and the results indicated that the recovered adsorbent could be used again for NH(4)(+) removal with nearly constant adsorption capacity. Thermodynamic parameters such as change in free energy (DeltaG(0)), enthalpy (DeltaH(0)) and entropy (DeltaS(0)) were also determined, which indicated that the adsorption was a spontaneous and exothermic process at ambient conditions. Compared with other adsorbents, the as-synthesized NaA zeolite displays a faster adsorption rate and higher adsorption capacity, which implies potential application for removing NH(4)(+) pollutants from wastewaters. Copyright 2010 Elsevier B.V. All rights reserved.

Biodegradation of crude oil saturated fraction supported on clays.

PubMed

Ugochukwu, Uzochukwu C; Jones, Martin D; Head, Ian M; Manning, David A C; Fialips, Claire I

2014-02-01

The role of clay minerals in crude oil saturated hydrocarbon removal during biodegradation was investigated in aqueous clay/saturated hydrocarbon microcosm experiments with a hydrocarbon degrading microorganism community. The clay minerals used for this study were montmorillonite, palygorskite, saponite and kaolinite. The clay mineral samples were treated with hydrochloric acid and didecyldimethylammonium bromide to produce acid activated- and organoclays respectively which were used in this study. The production of organoclay was restricted to only montmorillonite and saponite because of their relative high CEC. The study indicated that acid activated clays, organoclays and unmodified kaolinite, were inhibitory to biodegradation of the hydrocarbon saturates. Unmodified saponite was neutral to biodegradation of the hydrocarbon saturates. However, unmodified palygorskite and montmorillonite were stimulatory to biodegradation of the hydrocarbon saturated fraction and appears to do so as a result of the clays' ability to provide high surface area for the accumulation of microbes and nutrients such that the nutrients were within the 'vicinity' of the microbes. Adsorption of the saturated hydrocarbons was not significant during biodegradation.

Fire Events and Soil Thermometry: The Applications of Clay Chemistry for Tracing Temperature Changes in Soils and Sediments Below Surface Fires

NASA Astrophysics Data System (ADS)

Watson, E.; Werts, S. P.; Gelabert, M.

2016-12-01

Fires in the natural environment affect the physical, chemical, and biological properties of soils. However, fires may also alter the mineralogy of the geologic material in which it comes in contact. Previous experiments on high temperature alteration of clays indicate that dehydration, oxidation, and hydroxylation in clay minerals can occur progressively in that order at increasing temperatures up to 500°C. It is also well known that wildfire events can heat soils to these temperature ranges several centimeters deep. In this experiment, alterations in clay chemistry were used as a tool to investigate fire intensity along with the changing morphology of clay minerals. For data collection, small camp fires were set in York County, SC and temperatures were recorded using a datalogger system to 5 cm deep during the fire event. Control samples were taken adjacent to the fires to compare the changing morphology of the minerals when heated. Powder x-ray diffraction and scanning electron microscopy were used to identify the clay mineralogy. The clay from soil samples was identified as hydrous kaolinite, anhydrous kaolinite, and varying types of goethite. To observe the dehydration, oxidation, and hydroxylation of clay minerals, scanning electron microscopy with emission dispersive spectroscopy was used to identify the O/cation ratios present, which would indicate changes in the oxidation state of the clay minerals. By mapping the changes in O/cation ratios with temperature in silicates, we are able to trace the temperature of the sediments during fire events. This research suggests it may be possible to utilize these geochemical trends to aid in soil and sediment temperature investigations in both archeological and modern soil and surface process investigations.

Characterization and Activation of Indonesian Natural Zeolite from Southwest Aceh District-Aceh Province

NASA Astrophysics Data System (ADS)

Yulianis, Y.; Muhammad, S.; Pontas, K.; Mariana, M.; Mahidin, M.

2018-05-01

This study aims to identify the effect of activation processes of Indonesian zeolite from Southwest Aceh District, Aceh Province on the physical characteristics and chemical contents changes. The work was conducted by downsizing of natural zeolite into nano particle size, treating it physically (heated up to 105˚C) and chemically (soaked with 0.5 M HCl for 1 hour), and finally calcining it at the temperature of 350° C for 2 hours. The natural and activated nano zeolites were then characterized by using SEM, BET, XRD, XRF and FTIR in order to examine their characters and chemical contents. The characterization results showed that the activated nano zeolite has better appearances than the natural one. The XRD analysis showed that the main minerals of zeolite are quartz and calcite clinochlore. Further, the XRF analysis showed that there are elements of magnesium, calcium and potassium which can be as a cation exchange with other metal elements. Based on the identified properties, this zeolite showed a good performance to be used as an adsorbent in waste water treatment process, especially after activated.

Surface area effects on the reduction of U VI in the presence of synthetic montmorillonite

DOE PAGES

Boyanov, Maxim I.; Latta, Drew E.; Scherer, Michelle M.; ...

2016-12-14

Here, the redox transformations that affect the environmental mobility of metal or radionuclide contaminants typically take place in the presence of mineral or biological surfaces. Adsorption can alter the speciation and free energy of a dissolved ion and can thus change the occurrence, rate, or products of redox reactions relative to those expected in homogenous solution. Here, we investigated the effect of SYn-1, a redox-inactive synthetic montomorillonite clay mineral, on the reduction of U VI by dihydroanthraquinone-2,6 disulfonate (AH 2QDS, the reduced form of the soluble electron shuttle AQDS). We varied the surface:U ratio in a circumneutral bicarbonate solution andmore » measured the valence and atomic coordination of U in the solids using X-ray absorption spectroscopy (XANES and EXAFS). The spectra show that U IV was the predominant product both in the presence or absence of the clay mineral, indicating that adsorption of U VI to clay mineral surface sites does not affect its ability to be reduced by AH 2QDS. In the absence of the clay mineral and at low-to-intermediate surface:U ratios the predominant UIV product was nanoparticulate uraninite, UO 2. At the highest surface:U ratio tested (100 g/L clay mineral and 50 μM U) we observe a decrease in the proportion of uraninite down to 50%, with the remaining U IV present as adsorbed, non-uraninite species. These results are similar to previous findings with magnetite and rutile, where adsorbed U IV were the predominant species below a specific surface coverage and U in excess of this coverage was precipitated as uraninite. The threshold coverage determined here for the SYn-1 clay mineral is 10-100 × lower than that determined for magnetite and rutile, suggesting that clay mineral surfaces may be less important than metal oxides for stabilizing non-uraninite U IV species in natural sediments.« less

Surface area effects on the reduction of U VI in the presence of synthetic montmorillonite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boyanov, Maxim I.; Latta, Drew E.; Scherer, Michelle M.

Here, the redox transformations that affect the environmental mobility of metal or radionuclide contaminants typically take place in the presence of mineral or biological surfaces. Adsorption can alter the speciation and free energy of a dissolved ion and can thus change the occurrence, rate, or products of redox reactions relative to those expected in homogenous solution. Here, we investigated the effect of SYn-1, a redox-inactive synthetic montomorillonite clay mineral, on the reduction of U VI by dihydroanthraquinone-2,6 disulfonate (AH 2QDS, the reduced form of the soluble electron shuttle AQDS). We varied the surface:U ratio in a circumneutral bicarbonate solution andmore » measured the valence and atomic coordination of U in the solids using X-ray absorption spectroscopy (XANES and EXAFS). The spectra show that U IV was the predominant product both in the presence or absence of the clay mineral, indicating that adsorption of U VI to clay mineral surface sites does not affect its ability to be reduced by AH 2QDS. In the absence of the clay mineral and at low-to-intermediate surface:U ratios the predominant UIV product was nanoparticulate uraninite, UO 2. At the highest surface:U ratio tested (100 g/L clay mineral and 50 μM U) we observe a decrease in the proportion of uraninite down to 50%, with the remaining U IV present as adsorbed, non-uraninite species. These results are similar to previous findings with magnetite and rutile, where adsorbed U IV were the predominant species below a specific surface coverage and U in excess of this coverage was precipitated as uraninite. The threshold coverage determined here for the SYn-1 clay mineral is 10-100 × lower than that determined for magnetite and rutile, suggesting that clay mineral surfaces may be less important than metal oxides for stabilizing non-uraninite U IV species in natural sediments.« less

Solid-support substrates for plant growth at a lunar base

NASA Technical Reports Server (NTRS)

Ming, D. W.; Galindo, C.; Henninger, D. L.

1990-01-01

Zeoponics is only in its developmental stages at the Johnson Space Center and is defined as the cultivation of plants in zeolite substrates that contain several essential plant growth cations on their exchange sites, and have minor amounts of mineral phases and/or anion-exchange resins that supply essential plant growth anions. Zeolites are hydrated aluminosilicates of alkali and alkaline earth cations with the ability to exchange most of their constituent exchange cations as well as hydrate/dehydrate without change to their structural framework. Because zeolites have extremely high cation exchange capabilities, they are very attractive media for plant growth. It is possible to partially or fully saturate plant-essential cations on zeolites. Zeoponic systems will probably have their greatest applications at planetary bases (e.g., lunar bases). Lunar raw materials will have to be located that are suited for the synthesis of zeolites and other exchange resings. Lunar 'soil' simulants have been or are being prepared for zeolite/smectite synthesis and 'soil' dissolution studies.

Evaluation of Zeolite Permeable Treatment Wall for the Removal of Strontium-90 from Groundwater

NASA Astrophysics Data System (ADS)

Seneca, S. M.; Bandilla, K.; Rabideau, A. J.; Ross, E.; Bronner, C. E.

2009-12-01

Experimental and modeling studies are in progress to evaluate the potential performance of a permeable treatment wall comprised of zeolite-rich rock for the removal of strontium-90 from groundwater. Column studies were performed using a synthetic groundwater referenced to anticipate field conditions, with a focus on quantifying the competitive ion exchange among five cations (Na+, K+, Ca2+, Mg2+, and Sr2+). Ongoing studies are focused on the comparison of zeolites obtained from two sources: Teague Mineral Products (Adrian, OR) and Bear River Zeolite (Preston, UT), and on the possible influence of native soil that is mixed with treatment wall material during construction. The data obtained from the column studies is used to support robust estimation of zeolite cation exchange parameters producing a five-solute cation exchange model describing the removal efficiency of the zeolite. The field-scale transport model provides flexibility to explore design parameters to support the possible deployment of a full scale treatment wall at a Western New York nuclear facility.

Microbial reduction of Fe(III)-bearing clay minerals in the presence of humic acids

NASA Astrophysics Data System (ADS)

Liu, Guangfei; Qiu, Shuang; Liu, Baiqing; Pu, Yiying; Gao, Zhanming; Wang, Jing; Jin, Ruofei; Zhou, Jiti

2017-03-01

Both Fe(III)-bearing clay minerals and humic acids (HAs) are abundant in the soils and sediments. Previous studies have shown that bioreduction of structural Fe(III) in clay minerals could be accelerated by adding anthraquinone compound as a redox-active surrogate of HAs. However, a quinoid analogue could not reflect the adsorption and complexation properties of HA, and little is known about the effects of real HAs at environmental concentration on bioreduction of clay minerals. Here, it was shown that 10-200 mg l-1 of natural or artificially synthesized HAs could effectively stimulate the bioreduction rate and extent of Fe(III) in both iron-rich nontronite NAu-2 and iron-deficient montmorillonite SWy-2. After adsorption to NAu-2, electron-transfer activities of different HA fractions were compared. Additionally, Fe(II) complexation by HAs also contributed to improvement of clay-Fe(III) bioreduction. Spectrosopic and morphological analyses suggested that HA addition accelerated the transformation of NAu-2 to illite, silica and siderite after reductive dissolution.

Impact of Oriented Clay Particles on X-Ray Spectroscopy Analysis

NASA Astrophysics Data System (ADS)

Lim, A. J. M. S.; Syazwani, R. N.; Wijeyesekera, D. C.

2016-07-01

Understanding the engineering properties of the mineralogy and microfabic of clayey soils is very complex and thus very difficult for soil characterization. Micromechanics of soils recognize that the micro structure and mineralogy of clay have a significant influence on its engineering behaviour. To achieve a more reliable quantitative evaluation of clay mineralogy, a proper sample preparation technique for quantitative clay mineral analysis is necessary. This paper presents the quantitative evaluation of elemental analysis and chemical characterization of oriented and random oriented clay particles using X-ray spectroscopy. Three different types of clays namely marine clay, bentonite and kaolin clay were studied. The oriented samples were prepared by placing the dispersed clay in water and left to settle on porous ceramic tiles by applying a relatively weak suction through a vacuum pump. Images form a Scanning Electron Microscope (SEM) was also used to show the comparison between the orientation patterns of both the sample preparation techniques. From the quantitative analysis of the X-ray spectroscopy, oriented sampling method showed more accuracy in identifying mineral deposits, because it produced better peak intensity on the spectrum and more mineral content can be identified compared to randomly oriented samples.

Detailed mineral and chemical relations in two uranium-vanadium ores

USGS Publications Warehouse

Garrels, Robert M.; Larsen, E. S.; Pommer, A.M.; Coleman, R.G.

1956-01-01

Channel samples from two mines on the Colorado Plateau have been studied in detail both mineralogically and chemically. A channel sample from the Mineral Joe No. 1 mine, Montrose County, Colo., extends from unmineralized rock on one side, through a zone of variable mineralization, into only weakly mineralized rock. The unmineralized rock is a fairly clean quartz sand cemented with gypsum and contains only minor amounts of clay minerals. One boundary between unmineralized and mineralized rock is quite sharo and is nearly at right angles to the bedding. Vanadium clay minerals, chiefly mixed layered mica-montmorillonite and chlorite-monmorillonite, are abundant throughout the mineralized zone. Except in the dark "eye" of the channel sample, the vanadium clay minerals are accompanied by hewettite, carnotite, tyuyamunite, and probably unidentified vanadates. In the dark "eye," paramontroseite, pyrite, and marcasite are abundant, and bordered on each side by a zone containing abundant corvusite. No recognizable uranium minerals were seen in the paramontroseite zone although uranium is abundant there. Coaly material is recognizable throughout all of the channel but is most abundant in and near the dark "eye." Detailed chemical studies show a general increase in Fe, Al, U, and V, and a decrease in SO4 toward the "eye" of the channel. Reducing capacity studies indicate that V(IV) and Fe(II) are present in the clay mineral throughout the channel, but only in and near the "eye" are other V(IV) minerals present (paramontroseite and corvusite). The uranium is sexivalent, although its state of combination is conjectural where it is associated with paramontroseite. Where the ore boundary is sharp, the boundary of introduced trace elements is equally sharp. Textural and chemical relations leave no doubt that the "eye: is a partially oxidized remnant of a former lower-valence ore, and the remainder of the channel is a much more fully oxidized remnant. A channel sample from the Virgin No. 3 mine, Montrose County, Colo., extends from weakly mineralized sandstone on both sides through a strongly mineralized central zone. The weakly mineralized zone is a poorly sorted sandstone with common detrital clay partings; chlorite and mixed layer mica-montmorrillonite are abundant interstitial to the quartz grains. No distinct vanadium or uranium minerals are recognizable, although the clay minerals are vanadium bearing. Euherdral pyrite grains and selenian galena are present but rare. The strongly mineralized rock is separated from the weakly mineralized rock by a narrow transition zone which only apporiximates the bedding planes. It contains abundant vanadium-bearing clay minerals (predominantly chlorite) interstitial to the quartz grains, and apparently replacing them. Paramontroseite is common and is intergrown with the clay minerals. Pyrite and marcasite are present, chiefly in or near the abundant blebs and fragments of carbonaceous material. Selenian galena is rarely present, and generally in or near carbonaceous material. Coffinite is the only uranium mineral idenitified; it is extremely fine grained and was identified only in X-ray diffraction patterns of heavy separates. Distribution of trace elements is not clear; some are consistently high in the strongly mineralized rocks, and some are consistently low. The trace element composition of the unmineralized rock is not known. Chemical studies show a very abrupt rise in the total U, V, and Fe from the weakly mineralized to strongly mineralized rock. Reducing-capacity studies indicate that most of the vanadium is present as V(IV), but some is present as V(V); that iron is present as both Fe(II) and Fe(III), the latter believed to have been present in the primary clays of the unmineralized rock; and that come of the uranium is present as U(VI) in addition to the U(IV) in the coffinite. All evidence points to weak oxidation of an ore once having a somewhat lower valence state. The channel samples from both the Mineral Joe No. 1 mine and the Virgin No. 3 mine are believe to have been essentially identical in mineralogy prior to oxidation by weathering: vanadium was present as V(III) in montroseite and V(IV) in the vanadium clays; uranium was present largely as U(IV) in coffinite and/or uraninite. The Mineral Joe No. 1 mine channel sample is now more fully oxidized. Vanadium clays are unquestionably formed abundantly during the primary mineralization, and they persist with a minimum of alteration during much of the weathering. They suggest that the vanadium is carried as V(IV) in the ore-forming fluids; it seems likely too that the uranium is carried as a U(VI) ion.

Numerous nanopores developed in organo-clay complexes during the shale formations

NASA Astrophysics Data System (ADS)

Wang, Q.; Wang, T.; Lu, H.; Liao, J.

2017-12-01

Shale gas as new energy resource is either stored in nano pores and microfractures or absorbed on the surface of kerogen and clay aggregate (Chalmers et al., 2012). Nano pores developed in organic matters is very important, because these organic pores have better connectivity than inorganic pores (Loucks et al., 2012) and can form an effective pore system where shale gas flows dominantly (Curtis et al., 2010). In order to figure out how the organic pores is affected by shale compositions, we conduct in-situ FE-SEM and EDS analysis on organic-rich Longmaxi shales. The data indicate that 1) organic matter, mixed with clay minerals, can form an organo-clay complex containing many nanopores; 2)furthermore, larger organic pores are developed in organo-clay complexes with higher clay content than in those with lower clay content(Wang et al., 2017). It seems that the presence of organo-clay complex raises the heterogeneous than pure organic matters. Organo-clay complex may bring in lots of intergranular nanopores between organic matter and clay minerals. Another potential interpretation is that clay minerals may influence kerogen thermal decomposition, generation of hydrocarbons and thus the development of organic pores. The presence of numerous nanopores in organo-clay complexes may promote the connectivity of the pore network and enhance the hydrocarbon production efficiency for shale gas field.

Scanning electron microscopy of clays and clay minerals

USGS Publications Warehouse

Bohor, B.F.; Hughes, R.E.

1971-01-01

The scanning electron microscope (SEM) proves to be ideally suited for studying the configuration, texture, and fabric of clay samples. Growth mechanics of crystalline units—interpenetration and interlocking of crystallites, crystal habits, twinning, helical growth, and topotaxis—also are uniquely revealed by the SEM.Authigenic kaolins make up the bulk of the examples because their larger crystallite size, better crystallinity, and open texture make them more suited to examination by the SEM than most other clay mineral types.

Investigating the behaviour of Mg isotopes during the formation of clay minerals

NASA Astrophysics Data System (ADS)

Wimpenny, Joshua; Colla, Christopher A.; Yin, Qing-Zhu; Rustad, James R.; Casey, William H.

2014-03-01

We present elemental and isotopic data detailing how the Mg isotope system behaves in natural and experimentally synthesized clay minerals. We show that the bulk Mg isotopic composition (δ26Mg) of a set of natural illite, montmorillonite and kaolinite spans a 2‰ range, and that their isotopic composition depends strongly on a balance between the relative proportions of structural and exchangeable Mg. After acid leaching, these natural clays become relatively enriched in isotopically heavy Mg by between 0.2‰ and 1.6‰. Results of exchange experiments indicate that the Mg that has adsorbed to interlayer spaces and surface charged sites is relatively enriched in isotopically light Mg compared to the residual clay. The isotopic composition of this exchangeable Mg (-1.49‰ to -2.03‰) is characteristic of the isotopic composition of Mg found in many natural waters. Further experiments with an isotopically characterized MgCl2 solution shows that the clay minerals adsorb this exchangeable Mg with little or no isotopic fractionation, although we cannot discount the possibility that the uptake of exchangeable Mg does so with a slight preference for 24Mg. To characterize the behaviour of Mg isotopes during clay mineral formation we synthesized brucite (Mg(OH)2), which we consider to be a good analogue for the incorporation of Mg into the octahedral sheet of Mg-rich clay minerals or into the brucitic layer of clays such as chlorite. In our experiment the brucite mineral becomes enriched in the heavy isotopes of Mg while the corresponding solution is always relatively enriched in isotopically light Mg. The system reaches a steady state after 10 days with a final fractionation factor (αsolid-solution) of 1.0005 at near-neutral pH. This result is consistent with the general consensus that secondary clay minerals preferentially take up isotopically heavy Mg during their formation. However our results also show that exchangeable Mg is an important component within bulk clay minerals and can have an important influence over the bulk clay δ26Mg value. Modeling shows that in certain soils or sediments where the percentage of exchangeable Mg is >30% and the isotopic composition of the exchangeable Mg is around -2‰, the generation of bulk δ26Mg values of <-0.5‰ is likely. On a broader scale, Mg-rich minerals such as smectite and illite are likely to impart a stronger control over the Mg budget in clay rich sediments, and their high structural Mg component is likely to result in bulk sediment δ26Mg values that are closer in composition to the UCC. Despite this, results of modeling, together with experimental observation suggests that the uptake of exchangeable Mg into these clay rich sediments could cause a decrease in the bulk δ26Mg value by up to ˜0.3-0.4‰. This should be accounted for when assessing the δ26Mg value of sediments on a crustal scale.

Comment on "Evaluation of X-ray diffraction methods for determining the crystal growth mechanisms of clay minerals in mudstones, shales and slates," by L. N. Warr and D. R. Peacor

USGS Publications Warehouse

Eberl, D.D.; Srodon, J.; Drits, V.A.

2003-01-01

A recent paper by Warr and Peacor (2002) suggested that our use of the Bertaut-Warren-Averbach technique (MudMaster computer program) for studying changes in crystallite thickness distributions (CTDs) of clay minerals during diagenesis and very low-grade metamorphism is not reliable because it is dependent on many variables which can not be fully controlled. Furthermore, the authors implied that the measured shapes of CTDs cannot be used with confidence to deduce crystal growth mechanisms and histories for clays, based on our CTD simulation approach (using the Galoper computer program). We disagree with both points, and show that the techniques are powerful, reliable and useful for studying clay mineral alteration in rocks. ?? 2003 Schweiz. Mineral. Petrogr. Ges.

Fluoride content of clay minerals and argillaceous earth materials

USGS Publications Warehouse

Thomas, Josephus; Glass, H.D.; White, W.A.; Trandel, R.M.

1977-01-01

A reliable method, utilizing a fluoride ion-selective electrode, is described for the determination of fluoride in clays and shales. Interference by aluminum and iron is minimal. The reproducibility of the method is about ±5% at different levels of fluoride concentration.Data are presented for various clay minerals and for the <2-µm fractions of marine and nonmarine clays and shales. Fluoride values range from 44 ppm (0.0044%) for nontronite from Colfax, WA, to 51,800 ppm (5.18%) for hectorite from Hector, CA. In general, clays formed under hydrothermal conditions are relatively high in fluoride content, provided the hydrothermal waters are high in fluoride content. Besides hectorite, dickite from Ouray, CO, was found to contain more than 50 times as much fluoride (6700 ppm) as highly crystalline geode kaolinite (125 ppm). The clay stratum immediately overlying a fluorite mineralized zone in southern Illinois was found to have a higher fluoride content than the same stratum in a nonmineralized zone approximately 1 mile away. Nonmarine shales in contact with Australian coals were found to be lower in fluoride content than were marine shales in contact with Illinois coals.It is believed that, in certain instances, peak shifts on DTA curves of similar clay minerals are the result of significant differences in their fluoride content.

Timescales of carbon turnover in soils with mixed crystalline mineralogies

NASA Astrophysics Data System (ADS)

Khomo, Lesego; Trumbore, Susan; Bern, Carleton R.; Chadwick, Oliver A.

2017-01-01

Organic matter-mineral associations stabilize much of the carbon (C) stored globally in soils. Metastable short-range-order (SRO) minerals such as allophane and ferrihydrite provide one mechanism for long-term stabilization of organic matter in young soil. However, in soils with few SRO minerals and a predominance of crystalline aluminosilicate or Fe (and Al) oxyhydroxide, C turnover should be governed by chemisorption with those minerals. Here, we correlate mineral composition from soils containing small amounts of SRO minerals with mean turnover time (TT) of C estimated from radiocarbon (14C) in bulk soil, free light fraction and mineral-associated organic matter. We varied the mineral amount and composition by sampling ancient soils formed on different lithologies in arid to subhumid climates in Kruger National Park (KNP), South Africa. Mineral contents in bulk soils were assessed using chemical extractions to quantify Fe oxyhydroxides and SRO minerals. Because of our interest in the role of silicate clay mineralogy, particularly smectite (2 : 1) and kaolinite (1 : 1), we separately quantified the mineralogy of the clay-sized fraction using X-ray diffraction (XRD) and measured 14C on the same fraction. Density separation demonstrated that mineral associated C accounted for 40-70 % of bulk soil organic C in A and B1 horizons for granite, nephelinite and arid-zone gabbro soils, and > 80 % in other soils. Organic matter strongly associated with the isolated clay-sized fraction represented only 9-47 % of the bulk soil C. The mean TT of C strongly associated with the clay-sized fraction increased with the amount of smectite (2 : 1 clays); in samples with > 40 % smectite it averaged 1020 ± 460 years. The C not strongly associated with clay-sized minerals, including a combination of low-density C, the C associated with minerals of sizes between 2 µm and 2 cm (including Fe oxyhydroxides as coatings), and C removed from clay-sized material by 2 % hydrogen peroxide had TTs averaging 190 ± 190 years in surface horizons. Summed over the bulk soil profile, we found that smectite content correlated with the mean TT of bulk soil C across varied lithologies. The SRO mineral content in KNP soils was generally very low, except for the soils developed on gabbros under more humid climate that also had very high Fe and C contents with a surprisingly short, mean C TTs. In younger landscapes, SRO minerals are metastable and sequester C for long timescales. We hypothesize that in the KNP, SRO minerals represent a transient stage of mineral evolution and therefore lock up C for a shorter time. Overall, we found crystalline Fe-oxyhydroxides (determined as the difference between Fe in dithionate citrate and oxalate extractions) to be the strongest predictor for soil C content, while the mean TT of soil C was best predicted from the amount of smectite, which was also related to more easily measured bulk properties such as cation exchange capacity or pH. Combined with previous research on C turnover times in 2 : 1 vs. 1 : 1 clays, our results hold promise for predicting C inventory and persistence based on intrinsic timescales of specific carbon-mineral interactions.

Hyperspectral analysis of clay minerals

NASA Astrophysics Data System (ADS)

Janaki Rama Suresh, G.; Sreenivas, K.; Sivasamy, R.

2014-11-01

A study was carried out by collecting soil samples from parts of Gwalior and Shivpuri district, Madhya Pradesh in order to assess the dominant clay mineral of these soils using hyperspectral data, as 0.4 to 2.5 μm spectral range provides abundant and unique information about many important earth-surface minerals. Understanding the spectral response along with the soil chemical properties can provide important clues for retrieval of mineralogical soil properties. The soil samples were collected based on stratified random sampling approach and dominant clay minerals were identified through XRD analysis. The absorption feature parameters like depth, width, area and asymmetry of the absorption peaks were derived from spectral profile of soil samples through DISPEC tool. The derived absorption feature parameters were used as inputs for modelling the dominant soil clay mineral present in the unknown samples using Random forest approach which resulted in kappa accuracy of 0.795. Besides, an attempt was made to classify the Hyperion data using Spectral Angle Mapper (SAM) algorithm with an overall accuracy of 68.43 %. Results showed that kaolinite was the dominant mineral present in the soils followed by montmorillonite in the study area.

Impacts of Pantoea agglomerans strain and cation-modified clay minerals on the adsorption and biodegradation of phenanthrene.

PubMed

Tao, Kelin; Zhao, Song; Gao, Pin; Wang, Lijin; Jia, Hanzhong

2018-06-06

Interactions between microorganisms and minerals have the potential contribution to remove polycyclic aromatic hydrocarbons (PAHs) in model systems. In this study, phenanthrene (PHE) was used as a probe molecule to explore the potential adsorption and biotransformation processes in the presence of microorganisms and various reference clays, such as montmorillonite (M), kaolinite (K), and pyrophyllite (P). Equilibrium adsorption experiments and scanning electron microscopy (SEM) technique were used to investigate the sorption of Pantoea agglomerans strains on clay minerals saturated with cations (Na + and Fe 3+ ). The adsorption isotherms of PHE and Pantoea agglomerans strains on cation-modified clay minerals fitted to Langmuir equation, and their adsorbed amounts both followed the sequence: montmorillonite > kaolinite > pyrophyllite. For six types of cation-modified minerals, the behavior of PHE adsorbed and Pantoea agglomerans adhered onto mentioned minerals was in the order of Na(I)-M > Fe(Ⅲ)-M, Na(I)-K > Fe(Ⅲ)-K and Fe(Ⅲ)-P > Na(I)-P, respectively. The biodegradation results showed that cation-modified clay minerals could enhance the biodegradation of PHE, ascribing to their large specific surface area, and cation exchange capability, as well as the difference in zeta potential between minerals and Pantoea agglomerans strains. Comparison of biodegradation rates displayed that PHE was degraded the highest in the presence of Na-M (93.285%). In addition, the obtained results suggested that the adhesion of bacteria onto cation-exchanged clay minerals was beneficial to the biodegradation of PHE. Anthracen-9-ylmethanol and 3,4-dimethyl-2-(3-methylbutanoyl)benzoic acid were detected as the main intermediate compounds, which can be further biodegraded into small molecules. The overall results obtained in this study are of valuable significance for the understanding of the behavior of PHE in soil and associated environment. Copyright © 2018 Elsevier Inc. All rights reserved.

Mineralogical compositions of fault rocks from surface ruptures of Wenchuan earthquake and implication of mineral transformation during the seismic cycle along Yingxiu-Beichuan fault, Sichuan Province, China

NASA Astrophysics Data System (ADS)

Dang, Jiaxiang; Zhou, Yongsheng; He, Changrong; Ma, Shengli

2018-06-01

There are two co-seismic bedrock surface ruptures from the Mw 7.9 Wenchuan earthquake in the northern and central parts of the Beichuan-Yingxiu fault, Sichuan Province, southwest China. In this study, we report on the macrostructure of the fault rocks and results from X-ray powder diffraction analysis of minerals from rocks in the fault zone. The most recent fault gouge (the gouge produced by the most recent co-seismic fault movement) in all the studied outcrops is dark or grayish-black, totally unconsolidated and ultrafine-grained. Older fault gouges in the same outcrops are grayish or yellowish and weakly consolidated. X-ray powder diffraction analysis results show that mineral assemblages in both the old fault gouge and the new fault gouge are more complicated than the mineral assemblages in the bedrock as the fault gouge is rich in clay minerals. The fault gouge inherited its major rock-forming minerals from the parent rocks, but the clay minerals in the fault gouge were generated in the fault zone and are therefore authigenic and synkinematic. In profiles across the fault, clay mineral abundances increase as one traverses from the bedrock to the breccia to the old gouge and from the old gouge to the new gouge. Quartz and illite are found in all collected gouge samples. The dominant clay minerals in the new fault gouge are illite and smectite along the northern part of the surface rupture and illite/smectite mixed-layer clay in the middle part of the rupture. Illite/smectite mixed-layer clay found in the middle part of the rupture indicates that fault slip was accompanied by K-rich fluid circulation. The existence of siderite, anhydrite, and barite in the northern part of the rupture suggests that fault slip at this locality was accompanied by acidic fluids containing ions of Fe, Ca, and Ba.

Abiogenic photochemical synthesis on surface of meteorites and other small space bodies

NASA Astrophysics Data System (ADS)

Simakov, Michael B.; Kuzicheva, Eugenia A.

The abiogenic photochemical synthesis of complex biochemical compounds on the surface of small bodies in our Solar system was examined. Hydrated minerals are found within a chondrite matrix of meteorites together with significant amounts of organic matter. Clays are likely to have formed when water was present on parent meteoritic bodies. In order to verify the existence of a relationship between abiogenic synthesis of nucleotides and inorganic components of the meteorites, we have investigated possible abiogenic reactions associated with different clay (montmorillonite, kaolinite) and a basaltic one (Tyatya's volcanic ash) under action of open space energy sources as a model of different exobiological environments on the surface of small space bodies. The abiogenic synthesis of natural adenine nucleotides from a mixture of adenosine and inorganic phosphate has been observed following irradiation with VUV light in the presence of different mineral samples. The yields of the products (5'AMP, 2'AMP, 3'AMP, 2'3'cAMP and 3'5'cAMP) depended on irradiation time and kinds of minerals used. The discovery that meteoritic organic compounds may be trapped and protected within a clay mineral matrix has implications for our understanding of prebiotic molecular evolution in the early Solar system. Clay minerals may also have concentrated organic compounds thereby promoting polymerization reactions. An adsorption/binding of nucleic acids components by clay crystals could change the electron distribution and/or the conformation of the molecules. The remnant water molecules in the clay sheets also could influence the course of the reaction. Clay immobilization of phosphate could play an important role in this reaction. Chondritic material could have been a common component of the inner Solar system shortly after its formation and the biologically useful products of clay mineral-organic matter interactions could have also widespread, and delivered to planetary surfaces through the accretion of carbonaceous asteroids.

Characterization of Heat-treated Clay Minerals in the Context of Nuclear Waste Disposal

NASA Astrophysics Data System (ADS)

Matteo, E. N.; Wang, Y.; Kruichak, J. N.; Mills, M. M.

2015-12-01

Clay minerals are likely candidates to aid in nuclear waste isolation due to their low permeability, favorable swelling properties, and high cation sorption capacities. Establishing the thermal limit for clay minerals in a nuclear waste repository is a potentially important component of repository design, as flexibility of the heat load within the repository can have a major impact on the selection of repository design. For example, the thermal limit plays a critical role in the time that waste packages would need to cool before being transferred to the repository. Understanding the chemical and physical changes, if any, that occur in clay minerals at various temperatures above the current thermal limit (of 100 °C) can enable decision-makers with information critical to evaluating the potential trade-offs of increasing the thermal limit within the repository. Most critical is gaining understanding of how varying thermal conditions in the repository will impact radionuclide sorption and transport in clay materials either as engineered barriers or as disposal media. A variety of repository-relevant clay minerals (illite, mixed layer illite/smectite, and montmorillonite), were heated for a range of temperatures between 100-1000 °C. These samples were characterized to determine surface area, mineralogical alteration, and cation exchange capacity (CEC). Our results show that for conditions up to 500 °C, no significant change occurs, so long as the clay mineral remains mineralogically intact. At temperatures above 500 °C, transformation of the layered silicates into silica phases leads to alteration that impacts important clay characteristics. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's Nation Nuclear Security Administration under contract DE-AC04-94AL85000. SAND Number: SAND2015-6524 A

Clays and other minerals in prebiotic processes

NASA Technical Reports Server (NTRS)

Paecht-Horowitz, M.

1984-01-01

Clays and other minerals have been investigated in context with prebiotic processes, mainly in polymerization of amino acids. It was found that peptides adsorbed on the clay, prior to polymerization, influence the reaction. The ratio between the amount of the peptides adsorbed and that of the clay is important for the yield as well as for the degrees of polymerization obtained. Adsorption prior to reaction produces a certain order in the aggregates of the clay particles which might induce better reaction results. Excess of added peptides disturbs this order and causes lesser degrees of polymerization. In addition to adsorption, clays are also able to occlude between their layers substances out of the environment, up to very high concentrations.

Comparison of tetrachloromethane sorption to an alkylammonium-clay and an alkyldiammonium-clay

USGS Publications Warehouse

Smith, J.A.; Jaffe, P.R.

1991-01-01

The interlamellar space of Wyoming bentonite (clay) was modified by exchanging either decyltrimethyl-ammonium (DTMA) or decyltrimethyldiammonium (DTMDA) cations for inorganic ions, and tetrachloromethane sorption to the resulting two organoclays from water was studied at 10, 20, and 35??C. Only one end of the 10-carbon alkyl chain of the DTMA cation is attached to the silica surface of the clay mineral, and tetrachloromethane sorption of DTMA-clay is characterized by isotherm linearity, noncompetitive sorption, weak solute uptake, and a relatively low heat of sorption. Both ends of the 10-carbon chain of the DTMDA cation are attached to the silica surface of the clay mineral, and tetrachloromethane sorption to DTMDA-clay is characterized by nonlinear isotherms, competitive sorption, strong solute uptake, and a relatively high, exothermic heat of sorption that varies as a function of the mass of tetrachloromethane sorbed. Therefore, the attachment of both ends of the alkyl chain to the interlamellar mineral surface appears to change the sorption mechanism from a partition-dominated process to an adsorption-dominated process. ?? 1991 American Chemical Society.

Atom exchange between aqueous Fe(II) and structural Fe in clay minerals.

PubMed

Neumann, Anke; Wu, Lingling; Li, Weiqiang; Beard, Brian L; Johnson, Clark M; Rosso, Kevin M; Frierdich, Andrew J; Scherer, Michelle M

2015-03-03

Due to their stability toward reductive dissolution, Fe-bearing clay minerals are viewed as a renewable source of Fe redox activity in diverse environments. Recent findings of interfacial electron transfer between aqueous Fe(II) and structural Fe in clay minerals and electron conduction in octahedral sheets of nontronite, however, raise the question whether Fe interaction with clay minerals is more dynamic than previously thought. Here, we use an enriched isotope tracer approach to simultaneously trace Fe atom movement from the aqueous phase to the solid ((57)Fe) and from the solid into the aqueous phase ((56)Fe). Over 6 months, we observed a significant decrease in aqueous (57)Fe isotope fraction, with a fast initial decrease which slowed after 3 days and stabilized after about 50 days. For the aqueous (56)Fe isotope fraction, we observed a similar but opposite trend, indicating that Fe atom movement had occurred in both directions: from the aqueous phase into the solid and from the solid into aqueous phase. We calculated that 5-20% of structural Fe in clay minerals NAu-1, NAu-2, and SWa-1 exchanged with aqueous Fe(II), which significantly exceeds the Fe atom layer exposed directly to solution. Calculations based on electron-hopping rates in nontronite suggest that the bulk conduction mechanism previously demonstrated for hematite1 and suggested as an explanation for the significant Fe atom exchange observed in goethite2 may be a plausible mechanism for Fe atom exchange in Fe-bearing clay minerals. Our finding of 5-20% Fe atom exchange in clay minerals indicates that we need to rethink how Fe mobility affects the macroscopic properties of Fe-bearing phyllosilicates and its role in Fe biogeochemical cycling, as well as its use in a variety of engineered applications, such as landfill liners and nuclear repositories.

Soft X-ray spectromicroscopy study of mineral-organic matter associations in pasture soil clay fractions.

PubMed

Chen, Chunmei; Dynes, James J; Wang, Jian; Karunakaran, Chithra; Sparks, Donald L

2014-06-17

There is a growing acceptance that associations with soil minerals may be the most important overarching stabilization mechanism for soil organic matter. However, direct investigation of organo-mineral associations has been hampered by a lack of methods that can simultaneously characterize organic matter (OM) and soil minerals. In this study, STXM-NEXAFS spectroscopy at the C 1s, Ca 2p, Fe 2p, Al 1s, and Si 1s edges was used to investigate C associations with Ca, Fe, Al, and Si species in soil clay fractions from an upland pasture hillslope. Bulk techniques including C and N NEXAFS, Fe K-edge EXAFS spectroscopy, and XRD were applied to provide additional information. Results demonstrated that C was associated with Ca, Fe, Al, and Si with no separate phase in soil clay particles. In soil clay particles, the pervasive C forms were aromatic C, carboxyl C, and polysaccharides with the relative abundance of carboxyl C and polysaccharides varying spatially at the submicrometer scale. Only limited regions in the soil clay particles had aliphatic C. Good C-Ca spatial correlations were found for soil clay particles with no CaCO3, suggesting a strong role of Ca in organo-mineral assemblage formation. Fe EXAFS showed that about 50% of the total Fe in soils was contained in Fe oxides, whereas Fe-bearing aluminosilicates (vermiculite and Illite) accounted for another 50%. Fe oxides in the soil were mainly crystalline goethite and hematite, with lesser amounts of poorly crystalline ferrihydrite. XRD revealed that soil clay aluminosilicates were hydroxy-interlayered vermiculite, Illite, and kaolinite. C showed similar correlation with Fe to Al and Si, implying a similar association of Fe oxides and aluminosilicates with organic matter in organo-mineral associations. These direct microscopic determinations can help improve understanding of organo-mineral interactions in soils.

Mineralogy and thermal properties of clay from Slatina (Ub, Serbia)

NASA Astrophysics Data System (ADS)

Milosevic, Maja; Logar, Mihovil; Kaludjerovic, Lazar; Jelic, Ivana

2017-04-01

The "Slatina" deposit, Ub, Serbia was opened in 1965 and represents one of few deposits exploited by "Kopovi" a.d., Ub, company. Deposit is composed of clay layers belonging to Neogene sediments that are widespread transgressive over granitoid rocks of Cer mountain and Paleozoic and Mesozoic sediments. Clay is mostly of illite-montmorillonite-kaolinite type and they are generally used as ceramic materials while some of the layers are used as fire-resistant materials. In this study we present mineralogical and thermal characterization of two samples to determine their application as industrial materials. Chemical and mineral composition was determined using inductively coupled plasma optical emission spectroscopy (ICP-OES), X-ray diffraction (XRD) on powder and oriented samples, infrared spectroscopy (IR) and granulometry. Cationic exchange capacity (CEC) and specific surface area (SSA) was determined using spectrophotometry and methylene blue (MB). Thermal properties where determined by gravimetry (120, 350, 600 and 1000 oC) and differential thermal analysis (DTA). Quantitative mineral composition obtained by Rietveld refinement of combined chemical and XRD data shows that the sample 1(SC) is mainly smectite-illite (45%) and kaolinite (14%) clay with 19% of quartz, 10% feldspars and 7% of limonite, while sample 2(SV) is smectite-illite (43%) and kaolinite (11%) clay with 10% of quartz, 15% feldspars and 7% of limonite. Both samples have low content of impurities (carbonate minerals). Medium grain size (μm) goes from 1.02 (SSA = 104 m2/g) for sample 1(SC) to 0.71 (SSA = 117 m2/g) for sample 2(SV) while their CEC is 12.7 and 14.9 mmol/100g for 1(SC) and 2(SV) respectively. IR spectra of the samples shows larger amount of smectite clays with quartz and carbonate minerals for both samples which is in accordance with XRD data. DTA data shows couple of events that are endothermic. First one (100-200 oC) is associated with loss of moisture and constitutive water, second (300-400 oC) with iron hydroxide minerals, third (500-600 oC) with smectite clay content with smaller separate bands of kaolinite clays while events between 800-900 oC correspond to carbonate minerals. Loss of mass after gravimetry measurement at given temperatures shows that the samples have significant amount of water in their structure (≈3 wt% (120 oC)) with larger weight loss at 600 oC (3.06 and 3.37 wt%) while total weight loss is 9.12 and 9.08 wt% for 1(SC) and 2(SV) respectively. The studied clays from "Slatina" deposit have a medium content of smectite-illite minerals with smaller amount of kaolinite mineral together with quartz and feldspars. Based on their mineral composition and characteristics, possible application should be in different types of ceramic and construction industries. REFERENCES - M. Milošević, M. Logar, B. Dojčinović, A. Rosić and S. Erić, 2016, Diffuse reflectance spectra of methylene blue adsorbed on different types of clay samples, Clay Minerals, (2016) 5, 1-15

Origin and evolution of phyllosilicate deformation bands in the poorly lithified sandstones of the Rio do Peixe Basin, NE Brazil

NASA Astrophysics Data System (ADS)

Nogueira, Francisco; Nicchio, Matheus; Balsamo, Fabrizio; Bezerra, Francisco; Souza, Jorge; Carvalho, Bruno; Storti, Fabrizio

2017-04-01

In this work we describe the genetic processes and the microstructural evolution of phylossilicate deformation bands developed in poorly lithified, high porosity sandstones of the Rio do Peixe Basin, Northeast Brazil. The studied deformation bands occur in damage zones of NE-SW and NW-SE transtensional faults that exhibit well developed anastomosed clusters, with a thickness varying from tens of centimeters to 1 meter. The Host rocks are arkosic to lithic arkosic coarse sandstones to fine conglomerate and with less than 1% of clay content in the matrix. Based on (i) field observations, (ii) clay amount in deformation band cores and (iii) clay mineral arrangements in deformation bands cores, we identified two types of phyllosilicate deformation bands: (1) clay smearing deformation bands and (2) phyllosilicate deformation bands formed by clay authigenesis. The former occur only in fault zones that cut across clay-rich layers and are characterized by 45-50% of clay content. Single element chemical analysis indicates that the composition of clay minerals in clay smearing deformation bands is similar to that of clay-rich layers in the host rocks. The dominant deformation mechanism is particulate flow, which produces preferential alignments of grains and clay minerals. Only subordinate cataclasis occurs. Based on microstructural fabrics, three evolutionary stages can be identified for phyllosilicate deformation bands formed by clay authigenesis. The first one is characterized by preferentially cataclasis and weathering of feldspars. Clay concentration is relatively low, reaching 15-20%, with preferential concentration where crushed feldspar abundance is higher. The second stage is characterized by clay migration within deformation bands, to form continuous films with more than 20-25% of clay concentration. In the last stage clay mineral fabric re-organization occurs, forming well a developed S-C foliation. Clay concentration exceeds 35%. Single element chemical analysis indicates that the only external element present in phyllosilicate deformation bands formed by clay authigenesis is iron oxide. This feature suggests formation at very shallow depth, in the vadose zone where fluid flow preferentially occurs by capillarity in deformation band cores. Petrophysical analysis shows that both types of phyllosilicate deformation bands have high sealing potential. Clay smearing deformation bands reduce rock permeability by three orders of magnitude whereas phyllosilicate deformation bands formed by authigenesis causes permeability reduction of about two orders of magnitude with respect to the corresponding host rock.

Iron-rich clay minerals on Mars - Potential sources or sinks for hydrogen and indicators of hydrogen loss over time

NASA Technical Reports Server (NTRS)

Burt, D. M.

1989-01-01

Although direct evidence is lacking, indirect evidence suggests that iron-rich clay minerals or poorly-ordered chemical equivalents are widespread on the Martian surface. Such clays can act as sources or sinks for hydrogen ('hydrogen sponges'). Ferrous clays can lose hydrogen and ferric clays gain it by the coupled substitution Fe(3+)O(Fe(2+)OH)-1, equivalent to minus atomic H. This 'oxy-clay' substitution involves only proton and electron migration through the crystal structure, and therefore occurs nondestructively and reversibly, at relatively low temperatures. The reversible, low-temperature nature of this reaction contrasts with the irreversible nature of destructive dehydroxylation (H2O loss) suffered by clays heated to high temperatures. In theory, metastable ferric oxy-clays formed by dehydrogenation of ferrous clays over geologic time could, if exposed to water vapor, extract the hydrogen from it, releasing oxygen.

MODIFIED REVERSE OSMOSIS SYSTEM FOR TREATMENT OF PRODUCED WATERS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Robert L. Lee; Junghan Dong

2004-06-03

This final report of ''Modified Reverse Osmosis System for Treatment of Produced Water,'' DOE project No. DE-FC26-00BC15326 describes work performed in the third year of the project. Several good results were obtained, which are documented in this report. The compacted bentonite membranes were replaced by supported bentonite membranes, which exhibited the same salt rejection capability. Unfortunately, it also inherited the clay expansion problem due to water invasion into the interlayer spaces of the compacted bentonite membranes. We noted that the supported bentonite membrane developed in the project was the first of its kind reported in the literature. An {alpha}-alumina-supported MFI-typemore » zeolite membrane synthesized by in-situ crystallization was fabricated and tested. Unlike the bentonite clay membranes, the zeolite membranes maintained stability and high salt rejection rate even for a highly saline solution. Actual produced brines from gas and oil fields were then tested. For gas fields producing brine, the 18,300 ppm TDS (total dissolved solids) in the produced brine was reduced to 3060 ppm, an 83.3% rejection rate of 15,240 ppm salt rejection. For oilfield brine, while the TDS was reduced from 181,600 ppm to 148,900 ppm, an 18% rejection rate of 32,700 ppm reduction, the zeolite membrane was stable. Preliminary results show the dissolved organics, mainly hydrocarbons, did not affect the salt rejection. However, the rejection of organics was inconclusive at this point. Finally, the by-product of this project, the {alpha}-alumina-supported Pt-Co/Na Y catalytic zeolite membrane was developed and demonstrated for overcoming the two-step limitation of nonoxidation methane (CH{sub 4}) conversion to higher hydrocarbons (C{sub 2+}) and hydrogen (H{sub 2}). Detailed experiments to obtain quantitative results of H{sub 2} generation for various conditions are now being conducted. Technology transfer efforts included five manuscripts submitted to peer-reviewed journals and five conference presentations.« less

Clay mineral diversity and abundance in sedimentary rocks of Gale crater, Mars.

PubMed

Bristow, Thomas F; Rampe, Elizabeth B; Achilles, Cherie N; Blake, David F; Chipera, Steve J; Craig, Patricia; Crisp, Joy A; Des Marais, David J; Downs, Robert T; Gellert, Ralf; Grotzinger, John P; Gupta, Sanjeev; Hazen, Robert M; Horgan, Briony; Hogancamp, Joanna V; Mangold, Nicolas; Mahaffy, Paul R; McAdam, Amy C; Ming, Doug W; Morookian, John Michael; Morris, Richard V; Morrison, Shaunna M; Treiman, Allan H; Vaniman, David T; Vasavada, Ashwin R; Yen, Albert S

2018-06-01

Clay minerals provide indicators of the evolution of aqueous conditions and possible habitats for life on ancient Mars. Analyses by the Mars Science Laboratory rover Curiosity show that ~3.5-billion year (Ga) fluvio-lacustrine mudstones in Gale crater contain up to ~28 weight % (wt %) clay minerals. We demonstrate that the species of clay minerals deduced from x-ray diffraction and evolved gas analysis show a strong paleoenvironmental dependency. While perennial lake mudstones are characterized by Fe-saponite, we find that stratigraphic intervals associated with episodic lake drying contain Al-rich, Fe 3+ -bearing dioctahedral smectite, with minor (3 wt %) quantities of ferripyrophyllite, interpreted as wind-blown detritus, found in candidate aeolian deposits. Our results suggest that dioctahedral smectite formed via near-surface chemical weathering driven by fluctuations in lake level and atmospheric infiltration, a process leading to the redistribution of nutrients and potentially influencing the cycling of gases that help regulate climate.

Submicron structures provide preferential spots for carbon and nitrogen sequestration in soils

PubMed Central

Vogel, Cordula; Mueller, Carsten W.; Höschen, Carmen; Buegger, Franz; Heister, Katja; Schulz, Stefanie; Schloter, Michael; Kögel-Knabner, Ingrid

2014-01-01

The sequestration of carbon and nitrogen by clay-sized particles in soils is well established, and clay content or mineral surface area has been used to estimate the sequestration potential of soils. Here, via incubation of a sieved (<2 mm) topsoil with labelled litter, we find that only some of the clay-sized surfaces bind organic matter (OM). Surprisingly, <19% of the visible mineral areas show an OM attachment. OM is preferentially associated with organo-mineral clusters with rough surfaces. By combining nano-scale secondary ion mass spectrometry and isotopic tracing, we distinguish between new labelled and pre-existing OM and show that new OM is preferentially attached to already present organo-mineral clusters. These results, which provide evidence that only a limited proportion of the clay-sized surfaces contribute to OM sequestration, revolutionize our view of carbon sequestration in soils and the widely used carbon saturation estimates. PMID:24399306

Cross flow ultrafiltration of Cr (VI) using MCM-41, MCM-48 and Faujasite (FAU) zeolite-ceramic composite membranes.

PubMed

Basumatary, Ashim Kumar; Kumar, R Vinoth; Ghoshal, Aloke Kumar; Pugazhenthi, G

2016-06-01

This work describes the removal of Cr (VI) from aqueous solution in cross flow mode using MCM-41, MCM-48 and FAU zeolite membranes prepared on circular shaped porous ceramic support. Ceramic support was manufactured using locally available clay materials via a facile uni-axial compaction method followed by sintering process. A hydrothermal technique was employed for the deposition of zeolites on the ceramic support. The porosity of ceramic support (47%) is reduced by the formation of MCM-41 (23%), MCM-48 (22%) and FAU (33%) zeolite layers. The pore size of the MCM-41, MCM-48 and FAU membrane is found to be 0.173, 0.142, and 0.153 μm, respectively, which is lower than that of the support (1.0 μm). Cross flow ultrafiltration experiments of Cr (VI) were conducted at five different applied pressures (69-345 kPa) and three cross flow rates (1.11 × 10(-7) - 2.22 × 10(-7) m(3)/s). The filtration studies inferred that the performance of the fabricated zeolite composite membranes is optimum at the maximum applied pressure (345 kPa) and the highest rejection is obtained with the lowest cross flow rate (1.11 × 10(-7) m(3)/s) for all three zeolite membrane. The permeate flux of MCM-41, MCM-48 and FAU zeolite composite membranes are almost remained constant in the entire duration of the separation process. The highest removal of 82% is shown by FAU membrane, while MCM-41 and MCM-48 display 75% and 77% of Cr (VI) removal, respectively for the initial feed concentration of 1000 ppm with natural pH of the solution at an applied pressure of 345 kPa. Copyright © 2016 Elsevier Ltd. All rights reserved.

Ammonium removal from high-strength aqueous solutions by Australian zeolite.

PubMed

Wijesinghe, D Thushari N; Dassanayake, Kithsiri B; Sommer, Sven G; Jayasinghe, Guttila Y; J Scales, Peter; Chen, Deli

2016-07-02

Removal of ammonium nitrogen (NH4(+)-N) particularly from sources which are highly rich in nitrogen is important for addressing environmental pollution. Zeolites, aluminosilicate minerals, are commonly used as commercial adsorbents and ion-exchange medium in number of commercial applications due to its high adsorption capacity of ammonium (NH4(+)). However, detailed investigations on NH4(+) adsorption and ion exchange capacities of Australian natural zeolites are rare, particularly under higher NH4(+) concentrations in the medium. Therefore, this study was conducted to determine NH4(+) adsorption characteristics of Australian natural zeolites at high NH4(+) concentrations with and without other chemical compounds in an aqueous solution. Results showed that initial NH4(+) concentration, temperature, reaction time, and pH of the solution had significant effects on NH4(+) adsorption capacity of zeolite. Increased retention time and temperature generally had a positive impact on adsorption. Freundlich model fitted well with adsorption process of Australian natural zeolites; however, Langmuir model had best fitted for the adsorption process of sodium (Na(+)) treated zeolites. NaCl treatment increased the NH4(+) adsorption capacity of Australian zeolites by 25% at 1000 mg-N, NH4(+) solution. The maximum adsorption capacity of both natural Australian zeolites and Na(+) treated zeolites were estimated as 9.48 and 11.83 mg-N/g, respectively, which is lower than many zeolites from other sources. Compared to the NH4(+) only medium, presence of other competitive ions and acetic acid in the medium (resembling composition in digested swine manure slurries) reduced NH4(+) removal of natural and Na(+) treated zeolites by 44% and 57%, respectively. This suggests detailed investigations are required to determine practically achievable NH4(+) -N removal potential of zeolites for applications in complex mediums such as animal manure slurries.

The distribution and mobility of uranium in glassy and zeolitized tuff, Keg Mountain area, Utah, U.S.A.

USGS Publications Warehouse

Zielinski, R.A.; Lindsey, D.A.; Rosholt, J.N.

1980-01-01

The distribution and mobility of uranium in a diagenetically altered, 8 Ma old tuff in the Keg Mountain area, Utah, are modelled in this study. The modelling represents an improvement over similar earlier studies in that it: (1) considers a large number of samples (76) collected with good geologic control and exhibiting a wide range of alteration; (2) includes radiometric data for Th, K and RaeU (radium equivalent uranium) as well as U; (3) considers mineralogic and trace-element data for the same samples; and (4) analyzes the mineral and chemical covariation by multivariate statistical methods. The variation of U in the tuff is controlled mainly by its primary abundance in glass and by the relative abundance of non-uraniferous detritus and uraniferous accessory minerals. Alteration of glass to zeolite, even though extensive, caused no large or systematic change in the bulk concentration of U in the tuff. Some redistribution of U during diagenesis is indicated by association of U with minor alteration products such as opal and hydrous Fe-Mn oxide minerals. Isotopic studies indicate that the zeolitized tuff has been open to migration of U decay products during the last 0.8 Ma. The tuff of Keg Mountain has not lost a statistically detectable fraction of its original U, even though it has a high (??? 9 ppm) trace U content and has been extensively altered to zeolite. Similar studies in a variety of geological environments are required in order to identify the particular combination of conditions most favorable for liberation and migration of U from tuffs. ?? 1980.

A Fungal-Prokaryotic Consortium at the Basalt-Zeolite Interface in Subseafloor Igneous Crust

PubMed Central

Ivarsson, Magnus; Bengtson, Stefan; Skogby, Henrik; Lazor, Peter; Broman, Curt; Belivanova, Veneta; Marone, Federica

2015-01-01

We have after half a century of coordinated scientific drilling gained insight into Earth´s largest microbial habitat, the subseafloor igneous crust, but still lack substantial understanding regarding its abundance, diversity and ecology. Here we describe a fossilized microbial consortium of prokaryotes and fungi at the basalt-zeolite interface of fractured subseafloor basalts from a depth of 240 m below seafloor (mbsf). The microbial consortium and its relationship with the surrounding physical environment are revealed by synchrotron-based X-ray tomographic microscopy (SRXTM), environmental scanning electron microscopy (ESEM), and Raman spectroscopy. The base of the consortium is represented by microstromatolites—remains of bacterial communities that oxidized reduced iron directly from the basalt. The microstromatolites and the surrounding basalt were overlaid by fungal cells and hyphae. The consortium was overgrown by hydrothermally formed zeolites but remained alive and active during this event. After its formation, fungal hyphae bored in the zeolite, producing millimetre-long tunnels through the mineral substrate. The dissolution could either serve to extract metals like Ca, Na and K essential for fungal growth and metabolism, or be a response to environmental stress owing to the mineral overgrowth. Our results show how microbial life may be maintained in a nutrient-poor and extreme environment by close ecological interplay and reveal an effective strategy for nutrient extraction from minerals. The prokaryotic portion of the consortium served as a carbon source for the eukaryotic portion. Such an approach may be a prerequisite for prokaryotic-eukaryotic colonisation of, and persistence in, subseafloor igneous crust. PMID:26488482

[X-ray diffraction and infrared spectrum analysis of fault gouge in Wenchuan seismic belt].

PubMed

Wang, Zheng-Yang; Cao, Jian-Jin; Luo, Song-Ying; Liao, Yi-Peng

2014-05-01

Wenchuan earthquake produced a series of co-seismic surface ruptures in Leigu and Zhaojiagou, and we collected samples of co-seismic fault gouge in the surface ruptures as well as the old gouge in the fault of Nanba. Testing The new and old fault gouge was tested with X-ray diffraction and infrared absorption spectra, and its characteristics such as mineral compositions, clay mineral contents and combinations were comprehensively analyzed. The results display obvious differences between the new and old fault gouge, showing that the old fault gouge is mainly composed of wall rock debris or milled powders, while the main components of new fault gouge are clay minerals. The assemblage of clay minerals composition shows that the environment of the fault activity was mainly warm and humid, and the clay minerals were mainly transformed by low temperature and low pressure dynamic metamorphism. And this also partly indicates that the latest way of the fault activity in this area may be a creeping. However the previous researches on the fault gouge of Wenchuan earthquake fault zone are mainly focused on its mechanical properties as well as its texture and structure, the research in this paper is to determine the physical and chemical environment of fault activity through the mineral compositions and clay mineral contents in the fault gouge characteristics, and this research has important scientific significance to the researches on the evolution of the fault environment and the activity mechanism of the earthquake.

Bioreduction of Fe-bearing clay minerals and their reactivity toward pertechnetate (Tc-99)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bishop, Michael E.; Dong, Hailiang; Kukkadapu, Ravi K.

2011-07-01

99Technetium (99Tc) is a fission product of uranium-235 and plutonium-239 and poses a high environmental hazard due to its long half-life (t1/2 = 2.13 x 105 y), abundance in nuclear wastes, and environmental mobility under oxidizing conditions [i.e., Tc(VII)]. Under reducing conditions, Tc(VII) can be reduced to insoluble Tc(IV). Ferrous iron [Fe(II)], either in aqueous form or in mineral form, has been used to reduce Tc(VII) to Tc(IV). However, the reactivity of Fe(II) from clay minerals, other than nontronite, toward immobilization of Tc(VII) and its role in retention of reduced Tc(IV) have not been investigated. In this study the reactivitymore » of a suite of clay minerals toward Tc(VII) reduction and immobilization was evaluated. The clay minerals chosen for this study included five members in the smectite-illite (S-I) series, (montmorillonite, nontronite, rectorite, mixed layered I-S, and illite), chlorite, and palygorskite. Fe-oxides were removed from these minerals with a modified dithionite-citrate-bicarbonate (DCB) procedure. The total Fe content of these clay minerals, after Fe-oxide removal, ranged from 0.7 to 30.4% by weight, and the Fe(III)/Fe(total) ratio ranged from 44.9 to 98.5%. X-ray diffraction (XRD) and Mössbauer spectroscopy results showed that after Fe oxide removal the clay minerals were free of Fe-oxides. Scanning electron microscopy (SEM) revealed that little dissolution occurred during the DCB treatment. Bioreduction experiments were performed in bicarbonate buffer (pH-7) with Fe(III) in the clay minerals as the sole electron acceptor, lactate as the sole electron donor, and Shewanella Putrifaciens CN32 cells as mediators. In select tubes, anthraquinone-2,6-disulfate (AQDS) was added as electron shuttle to facilitate electron transfer. The extent of Fe(III) bioreduction was the highest for chlorite (~43 wt%) and the lowest for palygorskite (~4.17 wt%). In the S-I series, NAu-2 was the most reducible (~31 %) and illite the least (~0.4 %). The extent and initial rate of bioreduction were positively correlated with the percent smectite in the S-I series (i.e., layer expandability). Fe(II) in the bioreduced clay minerals subsequently was used to reduce Tc(VII) to Tc(IV) in PIPES buffer. Similar to the trend of bioreduction, in the S-I series, reduced smectite showed the highest reactivity toward Tc(VII), and reduced illite exhibited the least. The initial rate of Tc(VII) reduction, after normalization to clay and Fe(II) concentrations, was positively correlated with the percent smectite in the S-I series. Fe(II) in chlorite and palygorskite was also reactive toward Tc(VII) reduction. These data demonstrate that crystal chemical parameters (layer expandability, Fe and Fe(II) contents, and surface area etc.) play important roles in controlling the extent and rate of bioreduction and the reactivity toward Tc(VII) reduction. Reduced Tc(IV) resides within clay mineral matrix, and this association could minimize any potential of reoxidation over long term.« less

Arsenic(V) Removal in Wetland Filters Treating Drinking Water with Different Substrates and Plants

PubMed Central

Li, Qingyun; Tang, Xianqiang; Huang, Zhuo; Lin, Li; Scholz, Miklas

2014-01-01

Constructed wetlands are an attractive choice for removing arsenic (As) within water resources used for drinking water production. The role of substrate and vegetation in As removal processes is still poorly understood. In this study, gravel, zeolite (microporous aluminosilicate mineral), ceramsite (lightweight expanded clay aggregate) and manganese sand were tested as prospective substrates while aquatic Juncus effuses (Soft Rush or Common Rush) and terrestrial Pteris vittata L. (Chinese Ladder Brake; known as As hyperaccumulator) were tested as potential wetland plants. Indoor batch adsorption experiments combined with outdoor column experiments were conducted to assess the As removal performances and process mechanisms. Batch adsorption results indicated that manganese sand had the maximum As(V) adsorption rate of 4.55 h–1 and an adsorption capacity of 42.37 μg/g compared to the other three aggregates. The adsorption process followed the pseudo-first-order kinetic model and Freundlich isotherm equations better than other kinetic and isotherm models. Film-diffusion was the rate-limiting step. Mean adsorption energy calculation results indicated that chemical forces, particle diffusion and physical processes dominated As adsorption to manganese sand, zeolite and gravel, respectively. During the whole running period, manganese sand-packed wetland filters were associated with constantly 90% higher As(V) reduction of approximate 500 μg/L influent loads regardless if planted or not. The presence of P. vittata contributed to no more than 13.5% of the total As removal. In contrast, J. effuses was associated with a 24% As removal efficiency. PMID:24771958

Ultrafiltration by a compacted clay membrane-II. Sodium ion exclusion at various ionic strengths

USGS Publications Warehouse

Hanshaw, B.B.; Coplen, T.B.

1973-01-01

Several recent laboratory studies and field investigations have indicated that shales and compacted clay minerals behave as semipermeable membranes. One of the properties of semipermeable membranes is to retard or prevent the passage of charged ionic species through the membrane pores while allowing relatively free movement of uncharged species. This phenomenon is termed salt filtering, reverse osmosis, or ultrafiltration. This paper shows how one can proceed from the ion exchange capacity of clay minerals and, by means of Donnan membrane equilibrium concept and the Teorell-Meyer-Siever theory, develop a theory to explain why and to what extent ultrafiltration occurs when solutions of known concentration are forced to flow through a clay membrane. Reasonable agreement between theory and laboratory results were found. The concentration of the ultrafiltrate was always greater than predicted because of uncertainty in values of some parameters in the equations. Ultrafiltration phenomena may be responsible for the formation of some subsurface brines and mineral deposits. The effect should also be taken into consideration in any proposal for subsurface waste emplacement in an environment containing large quantities of clay minerals. ?? 1973.

Quantitative mineralogy of surface sediments of the Iceland shelf, and application to down-core studies of holocene ice-rafted sediments

USGS Publications Warehouse

Andrews, John T.; Eberl, D.D.

2007-01-01

Quantitative X-ray diffraction analyses on the < 2 mm sediment fraction from the Iceland shelves are reported for subglacial diamictons, seafloor surface sediments, and the last 2000 cal yr BP from two cores. The overall goal of the paper is to characterize the spatial variability of the mineralogy of the present-day surface sediments (18 non-clay minerals and 7 clay minerals), compare that with largely in situ erosional products typified by the composition of subglacial diamictons, and finally examine the late Holocene temporal variability in mineral composition using multi-mineral compositions. The subglacial diamictons are dominated in the non-clay-mineral fraction by the plagioclase feldspars and pyroxene with 36.7 ?? 6.1 and 17.9 ?? 3.5 wt % respectively, with smectites being the dominant clay minerals. The surface seafloor sediments have similar compositions although there are substantial amounts of calcite, plus there is a distinct band of sites from NW to N-central Iceland that contain 1-6 wt% of quartz. This latter distribution mimics the modern and historic pattern of drift ice in Iceland waters. Principal component analysis of the transformed wt% (log-ratio) non-clay minerals is used to compare the subglacial, surface, and down-core mineral compositions. Fifty-eight percent of the variance is explained by the first two axes, with dolomite, microcline, and quartz being important "foreign" species. These analyses indicate that today the NW-N-central Iceland shelf is affected by the import of exotic minerals, which are transported and released from drift ice. The down-core mineralogy indicates that this is a process that has varied over the last 2000 cal yr BP. Copyright ?? 2007, SEPM (Society for Sedimentary Geology).

Mineralogy of fine-grained alluvium from borehole U11g, expl. 1, northern Frenchman Flat area, Nevada Test Site

USGS Publications Warehouse

Jones, B.F.

1982-01-01

The mineralogy of matrix fines in alluvium from borehole Ullg, expl. 1, north of Frenchman Flat, Nevada Test Site, has been examined for evidence of past variations in water table elevation. Although greater abundance of zeolite and slightly more expanded basal spacings in smectite clays suggest effects of increased hydration of material up to 50 m above the present water table, these differences might also be related to provenance of environment of deposition. The relative uniformity of clay hydration properties in the 50 meters above the current water table suggest long-term stability near the present level. (USGS)

The effect of mineral composition on the sorption of cesium ions on geological formations.

PubMed

Kónya, József; Nagy, Noémi M; Nemes, Zoltán

2005-10-15

The sorption of cesium-137 on rock samples, mainly on clay rocks, is determined as a function of the mineral composition of the rocks. A relation between the mineral groups (tectosilicates, phyllosilicates, clay minerals, carbonates) and their cesium sorption properties is shown. A linear model is constructed by which the distribution coefficients of the different minerals can be calculated from the mineral composition and the net distribution coefficient of the rock. On the basis of the distribution coefficients of the minerals the cesium sorption properties of other rocks can be predicted.

Specific Features of Profile Distribution and Crystallochemistry of Phyllosilicates in Soils of the Cisbaikal Forest-Steppe

NASA Astrophysics Data System (ADS)

Chizhikova, N. P.; Gamzikov, G. P.; Chechetko, E. S.

2018-01-01

The mineralogical composition of agrogray, dark gray, and agro-dark gray soils (Luvic Greyzemic Retic Phaeozems); agro-dark gray residual-calcareous soils (Calcaric Cambic Phaeozems); clay-illuvial agrochernozems (Luvic Chernic Phaeozems); and agrochernozems with migrational-mycelial carbonates (Haplic Chernozems) developed in the forest-steppe of Central Siberia within the Irkutsk Depression has been studied. The clay (<1 μm) fraction separated from these soils consists of mixed-layer minerals with alternating layers of hydromica, smectite, vermiculite, and chlorite; the proportions between them change within the soil profiles. The clay fraction also contains hydromicas, kaolinite, chlorite, and some admixture of the fine-dispersed quartz. Each type of the soils is characterized by its own distribution pattern of clay material with specific alternation of layers in the mixed-layer formations. Mixed-layer minerals of the chlorite-vermiculite type predominate in the upper horizons of texture-differentiated soils. Down the soil profile, the content of mixed-layer mica-smectitic minerals increases. In the clay fraction of arable dark gray-humus soils with residual carbonates, the distribution of the clay fraction and major mineral phases in the soil profile is relatively even. An increased content of well-crystallized kaolinite is typical of these soils. The parent material of agrochernozems has a layered character: the upper horizons are generally depleted of clay, and the middle-profile and lower horizons are characterized by the considerable kaolinite content. In general, the clay material of soils of the Tulun-Irkutsk forest-steppe differs considerably from the clay material of foreststeppe soils developed from loesslike and mantle loams in the European part of Russia. In particular, this difference is seen in the proportions between major mineral phases and between biotitic and muscovitic components, as well as in the degree of crystallinity and behavior of kaolinite and chlorite.

Formation of stable nanocomposite clays from small peptides reacted with montmorillonite and illite-smectite mixed layer clays

NASA Astrophysics Data System (ADS)

Block, K. A.; Katz, A.; LeBlanc, J.; Peña, S.; Gottlieb, P.

2015-12-01

Understanding how organic compounds interact with clay minerals and which functional groups result in the strongest bonds is pivotal to achieving a better understanding of how mineral composition affects the residence time of carbon and nitrogen in soils. In this work, we describe how small peptides derived from tryptone casein digest are dissolved and suspended with clay minerals to examine the nature of OM adsorption to mineral surfaces and the resulting effect on clay mineral structure. XRD analyses indicate that peptides intercalation results in expansion of the d001 spacing of montmorillonite (Mt) and the smectite component of a 70-30 illite-smectite mixed layer clay (I-S) and poorer crystallinity overall as a result of exfoliation of tactoids. Peptide adsorption is concentration-dependent, however, surface adsorption appears to mediate interlayer adsorption in Mt reaching a maximum of 16% of the mass of the organoclay complex, indicating that at a critical concentration, peptide intercalation will supersede surface adsorption resulting in a more stable attachment. In I-S the degree of surface adsorption and intercalation is proportional to concentration, however, surface adsorption is not a priming mechanism for interlayer adsorption. Thermogravimetric analysis of the organoclay complexes determined by TGA coupled to GC-MS indicate that the most prominent product species measured was 1-(1-Trimethylsiloxyethenyl)-3-trimethylsiloxy-benzene, likely from tryptophan monomer decomposition. The compound was detected over a broad temperature range, greater than 300 oC, during pyrolysis and suggests a carbon-silicon covalent bond formed between the peptide and tetrahedral layers in the clay. An additional silicon-bearing VOC detected at lower pyrolysis temperature by GC was N,N-Diethyl-1-(trimethylsilyl)-9,10-didehydroergoline-8-carboxamide, likely derived from a lysine-bearing peptide derivative. We hypothesize that hydrophobic (non-ionic) peptides react with silanol at the clay platelet edges to induce exfoliation and subsequent formation of stable nanocomposite clays.

The origin and implications of clay minerals from Yellowknife Bay, Gale crater, Mars†

PubMed Central

Bristow, Thomas F.; Bish, David L.; Vaniman, David T.; Morris, Richard V.; Blake, David F.; Grotzinger, John P.; Rampe, Elizabeth B.; Crisp, Joy A.; Achilles, Cherie N.; Ming, Doug W.; Ehlmann, Bethany L.; King, Penelope L.; Bridges, John C.; Eigenbrode, Jennifer L.; Sumner, Dawn Y.; Chipera, Steve J.; Moorokian, John Michael; Treiman, Allan H.; Morrison, Shaunna M.; Downs, Robert T.; Farmer, Jack D.; Marais, David Des; Sarrazin, Philippe; Floyd, Melissa M.; Mischna, Michael A.; McAdam, Amy C.

2016-01-01

The Mars Science Laboratory (MSL) rover Curiosity has documented a section of fluvio-lacustrine strata at Yellowknife Bay (YKB), an embayment on the floor of Gale crater, approximately 500 m east of the Bradbury landing site. X-ray diffraction (XRD) data and evolved gas analysis (EGA) data from the CheMin and SAM instruments show that two powdered mudstone samples (named John Klein and Cumberland) drilled from the Sheepbed member of this succession contain up to ~20 wt% clay minerals. A trioctahedral smectite, likely a ferrian saponite, is the only clay mineral phase detected in these samples. Smectites of the two samples exhibit different 001 spacing under the low partial pressures of H2O inside the CheMin instrument (relative humidity <1%). Smectite interlayers in John Klein collapsed sometime between clay mineral formation and the time of analysis to a basal spacing of 10 Å, but largely remain open in the Cumberland sample with a basal spacing of ~13.2 Å. Partial intercalation of Cumberland smectites by metal-hydroxyl groups, a common process in certain pedogenic and lacustrine settings on Earth, is our favored explanation for these differences. The relatively low abundances of olivine and enriched levels of magnetite in the Sheepbed mudstone, when compared with regional basalt compositions derived from orbital data, suggest that clay minerals formed with magnetite in situ via aqueous alteration of olivine. Mass-balance calculations are permissive of such a reaction. Moreover, the Sheepbed mudstone mineral assemblage is consistent with minimal inputs of detrital clay minerals from the crater walls and rim. Early diagenetic fabrics suggest clay mineral formation prior to lithification. Thermodynamic modeling indicates that the production of authigenic magnetite and saponite at surficial temperatures requires a moderate supply of oxidants, allowing circum-neutral pH. The kinetics of olivine alteration suggest the presence of fluids for thousands to hundreds of thousands of years. Mineralogical evidence of the persistence of benign aqueous conditions at YKB for extended periods indicates a potentially habitable environment where life could establish itself. Mediated oxidation of Fe2+ in olivine to Fe3+ in magnetite, and perhaps in smectites provided a potential energy source for organisms. PMID:28798492

The origin and implications of clay minerals from Yellowknife Bay, Gale crater, Mars.

PubMed

Bristow, Thomas F; Bish, David L; Vaniman, David T; Morris, Richard V; Blake, David F; Grotzinger, John P; Rampe, Elizabeth B; Crisp, Joy A; Achilles, Cherie N; Ming, Doug W; Ehlmann, Bethany L; King, Penelope L; Bridges, John C; Eigenbrode, Jennifer L; Sumner, Dawn Y; Chipera, Steve J; Moorokian, John Michael; Treiman, Allan H; Morrison, Shaunna M; Downs, Robert T; Farmer, Jack D; Marais, David Des; Sarrazin, Philippe; Floyd, Melissa M; Mischna, Michael A; McAdam, Amy C

2015-04-01

The Mars Science Laboratory (MSL) rover Curiosity has documented a section of fluvio-lacustrine strata at Yellowknife Bay (YKB), an embayment on the floor of Gale crater, approximately 500 m east of the Bradbury landing site. X-ray diffraction (XRD) data and evolved gas analysis (EGA) data from the CheMin and SAM instruments show that two powdered mudstone samples (named John Klein and Cumberland) drilled from the Sheepbed member of this succession contain up to ~20 wt% clay minerals. A trioctahedral smectite, likely a ferrian saponite, is the only clay mineral phase detected in these samples. Smectites of the two samples exhibit different 001 spacing under the low partial pressures of H 2 O inside the CheMin instrument (relative humidity <1%). Smectite interlayers in John Klein collapsed sometime between clay mineral formation and the time of analysis to a basal spacing of 10 Å, but largely remain open in the Cumberland sample with a basal spacing of ~13.2 Å. Partial intercalation of Cumberland smectites by metal-hydroxyl groups, a common process in certain pedogenic and lacustrine settings on Earth, is our favored explanation for these differences. The relatively low abundances of olivine and enriched levels of magnetite in the Sheepbed mudstone, when compared with regional basalt compositions derived from orbital data, suggest that clay minerals formed with magnetite in situ via aqueous alteration of olivine. Mass-balance calculations are permissive of such a reaction. Moreover, the Sheepbed mudstone mineral assemblage is consistent with minimal inputs of detrital clay minerals from the crater walls and rim. Early diagenetic fabrics suggest clay mineral formation prior to lithification. Thermodynamic modeling indicates that the production of authigenic magnetite and saponite at surficial temperatures requires a moderate supply of oxidants, allowing circum-neutral pH. The kinetics of olivine alteration suggest the presence of fluids for thousands to hundreds of thousands of years. Mineralogical evidence of the persistence of benign aqueous conditions at YKB for extended periods indicates a potentially habitable environment where life could establish itself. Mediated oxidation of Fe 2+ in olivine to Fe 3+ in magnetite, and perhaps in smectites provided a potential energy source for organisms.

Clays, specialty

USGS Publications Warehouse

Virta, R.L.

1998-01-01

Part of a special section on the state of industrial minerals in 1997. The state of the specialty clay industry worldwide for 1997 is discussed. The specialty clays mined in the U.S. are ball clay, fuller's earth, bentonite, fire clay, and kaolin. Sales of specialty clays in the U.S. were around 17 Mt in 1997. Approximately 53 kt of specialty clays were imported.

Quorum Sensing Disruption in Vibrio harveyi Bacteria by Clay Materials.

PubMed

Naik, Sajo P; Scholin, Jonathon; Ching, San; Chi, Fang; Herpfer, Marc

2018-01-10

This work describes the use of clay minerals as catalysts for the degradation of quorum sensing molecule N-(3-oxooctanoyl)-dl-homoserine lactone. Certain clay minerals as a result of their surface properties and porosity can catalytically degrade the quorum sensing molecule into smaller fragments. The disruption of quorum sensing by clay in a growing Gram-negative Vibrio harveyi bacteria culture was also studied by monitoring luminescence and population density of the bacteria, wherein quenching of bacterial quorum sensing activity was observed by means of luminescence reduction. The results of this study show that food-grade clays can be used as biocatalysts in disrupting bacterial activity in various media.

Application of mixed based membrane technology from component materials bintaro, zeolite and bentonite to reduction of songket waste liquid cloth

NASA Astrophysics Data System (ADS)

Dahlan, Muhammad Hatta; Saleh, Abdullah; Asip, Faisol; Makmun, Akbar; Defi

2017-11-01

Application of membrane technology based on clay mixture, Activated Carbon from Bintaro, Zeolite and Bentonit to process the waste water of Songket cloth is Palembang traditionally cloth. The applied research is into the superior field of industrial and household waste processing with membrane ceramic technology. The objective of this research is to design the liquid waste separation tool of jumputan cloth using better and simpler ceramic membrane so that it can help the artisans of Palembang songket or songket in processing the waste in accordance with the standard of environmental quality standard (BML) and Pergub Sumsel no. 16 in 2005. The specific target to be achieved can decrease the waste of cloth jumputan in accordance with applicable environmental quality standards the method used in achieving the objectives of this study using 2 processes namely the adsorption process using activated carbon and the separation process using a ceramic membrane based on the composition of the mixture. The activated carbon from bintaro seeds is expected to decrease the concentration of liquid waste of Songket cloth. Bintaro seeds are non-edible fruits where the composition contains organic ingredients that can absorb because contains dyes and filler metals. The process of membranization in the processing is expected to decrease the concentration of waste better and clear water that can be used as recycled water for household use. With the composition of a mixture of clay-based materials: zeolite, bentonit, activated carbon from bintaro seeds are expected Find the solution and get the novelty value in the form of patent in this research

Report on "Methodologies for Investigating Microbial-Mineral Interactions: A Clay Minerals Society Short Course"

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maurice, Patricia A.

2010-02-08

A workshop entitled, “Methods of Investigating Microbial-Mineral Interactions,” was held at the Clay Minerals Society meeting at the Pacific Northwest National Laboratory in Richland, WA on June 19, 2004. The workshop was organized by Patricia A. Maurice (University of Notre Dame) and Lesley A. Warren (McMaster University, CA). Speakers included: Dr. P. Bennett, Dr. J. Fredrickson (PNNL), Dr. S. Lower (Ohio State University), Dr. P. Maurice, Dr. S. Myneni (Princeton University), Dr. E. Shock (Arizona State), Dr. M. Tien (Penn State), Dr. L. Warren, and Dr. J. Zachara (PNNL). There were approximately 75 attendees at the workshop, including more thanmore » 20 students. A workshop volume was published by the Clay Minerals Society [Methods for Study of Microbe-Mineral Interactions (2006), CMS Workshop Lectures, vol 14(Patricia A. Maurice and Leslie A. Warren, eds.) ISBN 978-1-881208-15-0, 166 pp.]« less

Reduction And Immobilization Of Hexavalent Chromium By Microbially Reduced Fe-bearing Clay Minerals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bishop, Michael E.; Glasser, Paul; Dong, Hailiang

Hexavalent chromium (Cr6+) is a major contaminant in the environment. As a redox-sensitive element, the fate and toxicity of chromium is controlled by reduction-oxidation (redox) reactions. Previous research has shown the ability of structural Fe(II) in naturally present and chemically reduced clay minerals to reduce Cr6+ to Cr(III) as a way of immobilization and detoxification. However, it is still poorly known whether or not structural Fe(II) in biologically reduced clay minerals exhibits a similar reactivity and if so, what the kinetics and mechanisms of Cr6+ reduction are. The objective of this study was to determine the kinetics and possible mechanismsmore » of Cr6+ reduction by structural Fe(II) in microbially reduced clay minerals and the nature of reduced Cr(III). Structural Fe(III) in nontronite (NAu-2), montmorillonite (SWy-2), chlorite (CCa-2), and clay-rich sediments from the Ringold Formation of the Hanford site of Washington State, USA was first bioreduced to Fe(II) by an iron-reducing bacterium Geobacter sulfurreducens with acetate as the sole electron donor and anthraquinone-2,6-disulfate (AQDS) as electron shuttle in synthetic groundwater (pH 7). Biogenic Fe(II) was then used to reduce aqueous Cr6+ at three different temperatures, 10°, 20°, and 30°C, in order to determine the temperature dependence of the redox reaction between Cr6+ and clay-Fe(II). The results showed that nontronite and montmorillonite were most effective in reducing aqueous Cr6+ at all three temperatures. In contrast, most Fe(II) in chlorite was not reactive towards Cr6+ reduction at 10°C, though at 30°C there was some reduction. For all the clay minerals, the ratio of total Fe(II) oxidized to Cr6+ reduced was close to the expected stoichiometric value of 3. Characterization of the Cr-clay reaction product with scanning electron microscopy with focused ion beam and transmission electron microscopy with electron energy loss spectroscopy revealed that reduced chromium was possibly in the form of sub-nanometer Cr2O3 in association with residual clay minerals as micro-aggregates. This textural association was expected to minimize the chance of Cr(III) reoxidation upon exposure to oxidants. These results are important for our understanding of how various clay minerals may be used to reductively immobilize the heavy metal contaminant Cr in the environment.« less

Timescales of carbon turnover in soils with mixed crystalline mineralogies

USGS Publications Warehouse

Khomo, Lesego; Trumbore, Susan E.; Bern, Carleton R.; Chadwick, Oliver A.

2017-01-01

Organic matter–mineral associations stabilize much of the carbon (C) stored globally in soils. Metastable short-range-order (SRO) minerals such as allophane and ferrihydrite provide one mechanism for long-term stabilization of organic matter in young soil. However, in soils with few SRO minerals and a predominance of crystalline aluminosilicate or Fe (and Al) oxyhydroxide, C turnover should be governed by chemisorption with those minerals. Here, we correlate mineral composition from soils containing small amounts of SRO minerals with mean turnover time (TT) of C estimated from radiocarbon (14C) in bulk soil, free light fraction and mineral-associated organic matter. We varied the mineral amount and composition by sampling ancient soils formed on different lithologies in arid to subhumid climates in Kruger National Park (KNP), South Africa. Mineral contents in bulk soils were assessed using chemical extractions to quantify Fe oxyhydroxides and SRO minerals. Because of our interest in the role of silicate clay mineralogy, particularly smectite (2 : 1) and kaolinite (1 : 1), we separately quantified the mineralogy of the clay-sized fraction using X-ray diffraction (XRD) and measured 14C on the same fraction. Density separation demonstrated that mineral associated C accounted for 40–70 % of bulk soil organic C in A and B1 horizons for granite, nephelinite and arid-zone gabbro soils, and > 80 % in other soils. Organic matter strongly associated with the isolated clay-sized fraction represented only 9–47 % of the bulk soil C. The mean TT of C strongly associated with the clay-sized fraction increased with the amount of smectite (2 : 1 clays); in samples with > 40 % smectite it averaged 1020 ± 460 years. The C not strongly associated with clay-sized minerals, including a combination of low-density C, the C associated with minerals of sizes between 2 µm and 2 cm (including Fe oxyhydroxides as coatings), and C removed from clay-sized material by 2 % hydrogen peroxide had TTs averaging 190 ± 190 years in surface horizons. Summed over the bulk soil profile, we found that smectite content correlated with the mean TT of bulk soil C across varied lithologies. The SRO mineral content in KNP soils was generally very low, except for the soils developed on gabbros under more humid climate that also had very high Fe and C contents with a surprisingly short, mean C TTs. In younger landscapes, SRO minerals are metastable and sequester C for long timescales. We hypothesize that in the KNP, SRO minerals represent a transient stage of mineral evolution and therefore lock up C for a shorter time. Overall, we found crystalline Fe-oxyhydroxides (determined as the difference between Fe in dithionate citrate and oxalate extractions) to be the strongest predictor for soil C content, while the mean TT of soil C was best predicted from the amount of smectite, which was also related to more easily measured bulk properties such as cation exchange capacity or pH. Combined with previous research on C turnover times in 2 : 1 vs. 1 : 1 clays, our results hold promise for predicting C inventory and persistence based on intrinsic timescales of specific carbon–mineral interactions.

Optimization for zeolite regeneration and nitrogen removal performance of a hypochlorite-chloride regenerant.

PubMed

Zhang, Wei; Zhou, Zhen; An, Ying; Du, Silu; Ruan, Danian; Zhao, Chengyue; Ren, Ning; Tian, Xiaoce

2017-07-01

Simultaneous zeolites regeneration and nitrogen removal were investigated by using a mixed solution of NaClO and NaCl (NaClO-NaCl solution), and effects of the regenerant on ammonium removal performance and textural properties of zeolites were analyzed by long-term adsorption and regeneration operations. Mixed NaClO-NaCl solution removed more NH 4 + exchanged on zeolites and converted more of them to nitrogen than using NaClO or NaCl solution alone. Response surface methodological analysis indicated that molar ratio of hypochlorite and nitrogen (ClO - /N), NaCl concentration and pH value all had significant effects on zeolites regeneration and NH 4 + conversion to nitrogen, and the optimum condition was obtained at ClO - /N of 1.75, NaCl concentration of 20 g/L and pH of 10.0. Zeolites regenerated by mixed NaClO-NaCl solution showed higher ammonium adsorption rate and lower capacity than unused zeolites. Zeolites and the regeneration solution were both effective even after 20 cycles of use. Composition and morphological analysis revealed that the main mineral species and surface morphology of zeolites before and after NaClO-NaCl regeneration were unchanged. Textural analysis indicated that NaClO-NaCl regeneration leads to an increased surface area of zeolites, especially the microporosity. The results indicated that NaClO-NaCl regeneration is an attractive method to achieve sustainable removal of nitrogen from wastewater through zeolite. Copyright © 2017 Elsevier Ltd. All rights reserved.

The Lacustrine Upper Brushy Basin Member of the Morrison Formation, Four Corners Region, Usa: a Lithological and Mineralogical Terrestrial Analog for Gale Crater, Mars

NASA Astrophysics Data System (ADS)

Potter-McIntyre, S. L.; Chan, M. A.; McPherson, B. J.

2013-12-01

The upper part of the Jurassic Brushy Basin Member of the Morrison Formation is an iron- and clay-rich volcaniclastic shale deposited in an ephemeral alkaline saline lake system. Sedimentary rocks exposed in Gale Crater consist of similar non-acidic clays, possibly of lacustrine origin. Three primary clastic lithofacies are present in both the Brushy Basin Member and at Gale Crater: silt-/claystone, sandstone, and conglomerate. Both the terrestrial and martian silt-/claystone lithofacies are interpreted as lacustrine depositional environments due to features such as parallel laminated and massive sedimentary structures. Vugs are present in the siltstone/claystone facies on both the Colorado Plateau and at Gale Crater. Fluvial features are also observed in both examples such as cross-bedded sandstones and imbricated conglomerates. Concretions are present in both the Colorado Plateau and Gale Crater units. The vugs in the Brushy Basin Member preserve algal forms with cellular elaboration and are interpreted as charophyte molds. Two distinct suites of elements (1. C, Fe, As, P and, 2. C, S, Se, P) are associated with the microbial fossils and may be potential markers for biosignatures. Vugs at Gale Crater are a potential target to investigate the possibility of preserved microbial (algal) life where early analyses show the presence of the elements capable of supporting life. The Brushy Basin Member is composed predominately of quartz, feldspars, zeolites and altered volcanic ash. The abundant clay minerals in both the terrestrial and martian examples are hypothesized to have formed due to partial alteration of volcanic minerals in alkaline fluid. Similarly, concretions present in the terrestrial unit exhibit a diverse range of mineralogies likely due to alkaline fluid chemistries interacting with reactive volcaniclastic sediments. Terrestrial concretion mineralogy is diverse even within an outcrop or stratigraphic horizon which suggests reactants to precipitate concretions are being sourced from diagenetic micorenvironments. Similar diagenetic microenvironments may be preserved at Gale Crater due to the fine-grained, volcaniclastic (reactive) rocks. The Brushy Basin Member is a valuable analog because comparative iron-and clay-rich compositions help to: 1) understand diagenetic processes in a non-acidic, saline lacustrine environment, 2) document specific sedimentary structures and lithofacies associations to interpret depositional environment, 3) document specific biomediated features (e.g., textures, morphologies, chemistries), and 4) demonstrate how these features might persist or respond to diagenesis over time.

Clay alteration and gold deposition in the genesis and blue star deposits, Eureka County, Nevada

USGS Publications Warehouse

Drews-Armitage, S. P.; Romberger, S.B.; Whitney, C.G.

1996-01-01

The Genesis and Blue Star sedimentary rock-hosted gold deposits occur within the 40-mile-long Carlin trend and are located in Eureka County, Nevada. The deposits are hosted within the Devonian calcareous Popovich Formation, the siliciclastic Rodeo Creek unit and the siliciclastic Vinini Formation. The host rocks have undergone contact metamorphism, decalcification, silicification, argillization, and supergene oxidation. Detailed characterization of the alteration patterns, mineralogy, modes of occurrence, and associated geochemistry of clay minerals resulted in the following classifications: least altered rocks, found distal to the orebody, consisting of both metamorphosed and unmetamorphosed host rock that has not been completely decalcified; and altered rocks, found proximal to the orebody that have been decalcified. Altered rocks are classified further into the following groups based on clay mineral content: silicic, 1 to 10 percent clay; silicicargillic, 10 to 35 percent clay; and argillic, 35 to 80 percent clay. Clay species identified are 1M illite, 2M1 illite, kaolinite, halloysite, and dioctahedral smectite. An early hydrothermal event resulted in the precipitation of euhedral kaolinite and at least one generation of silica. This event occurred contemporaneously with decalcification which increased rock permeability and porosity. A second clay alteration event resulted in the precipitation of hydrothermal 1M illite which replaced hydrothermal kaolinite and is associated with gold deposition. Silver and silica deposition is also associated with this phase of hydrothermal alteration. Hydrothermal alteration was followed by supergene alteration which resulted in the formation of supergene kaolinite, halloysite, and smectite as well as the oxidation of iron-bearing minerals. Supergene clays are concentrated along faults, dike margins, and within rocks containing carbonate. Gold mineralization is not associated with supergene clay minerals within the Genesis and Blue Star deposits. Rocks classified as silicic-argillic in the Popovich Formation represent the most significant gold host. Silicicargillic rocks commonly exhibit bedding-parallel alteration zones. This pattern of alteration indicates that stratigraphy as well as northwest-trending structures played a significant role in the migration of gold-bearing fluids. Based on K-Ar age determinations of hydrothermal 1M illite associated with gold, the main event of mineralization in the Genesis and Blue Star deposits occurred between 93 and 100 Ma, during mid-Cretaceous time.

Two-way Valorization of Blast Furnace Slag: Synthesis of Precipitated Calcium Carbonate and Zeolitic Heavy Metal Adsorbent.

PubMed

Georgakopoulos, Evangelos; Santos, Rafael M; Chiang, Yi Wai; Manovic, Vasilije

2017-02-21

The aim of this work is to present a zero-waste process for storing CO2 in a stable and benign mineral form while producing zeolitic minerals with sufficient heavy metal adsorption capacity. To this end, blast furnace slag, a residue from iron-making, is utilized as the starting material. Calcium is selectively extracted from the slag by leaching with acetic acid (2 M CH3COOH) as the extraction agent. The filtered leachate is subsequently physico-chemically purified and then carbonated to form precipitated calcium carbonate (PCC) of high purity (<2 wt% non-calcium impurities, according to ICP-MS analysis). Sodium hydroxide is added to neutralize the regenerated acetate. The morphological properties of the resulting calcitic PCC are tuned for its potential application as a filler in papermaking. In parallel, the residual solids from the extraction stage are subjected to hydrothermal conversion in a caustic solution (2 M NaOH) that leads to the predominant formation of a particular zeolitic mineral phase (detected by XRD), namely analcime (NaAlSi2O6∙H2O). Based on its ability to adsorb Ni 2+ , as reported from batch adsorption experiments and ICP-OES analysis, this product can potentially be used in wastewater treatment or for environmental remediation applications.

Two-way Valorization of Blast Furnace Slag: Synthesis of Precipitated Calcium Carbonate and Zeolitic Heavy Metal Adsorbent

PubMed Central

Georgakopoulos, Evangelos; Santos, Rafael M.; Chiang, Yi Wai; Manovic, Vasilije

2017-01-01

The aim of this work is to present a zero-waste process for storing CO2 in a stable and benign mineral form while producing zeolitic minerals with sufficient heavy metal adsorption capacity. To this end, blast furnace slag, a residue from iron-making, is utilized as the starting material. Calcium is selectively extracted from the slag by leaching with acetic acid (2 M CH3COOH) as the extraction agent. The filtered leachate is subsequently physico-chemically purified and then carbonated to form precipitated calcium carbonate (PCC) of high purity (<2 wt% non-calcium impurities, according to ICP-MS analysis). Sodium hydroxide is added to neutralize the regenerated acetate. The morphological properties of the resulting calcitic PCC are tuned for its potential application as a filler in papermaking. In parallel, the residual solids from the extraction stage are subjected to hydrothermal conversion in a caustic solution (2 M NaOH) that leads to the predominant formation of a particular zeolitic mineral phase (detected by XRD), namely analcime (NaAlSi2O6∙H2O). Based on its ability to adsorb Ni2+, as reported from batch adsorption experiments and ICP-OES analysis, this product can potentially be used in wastewater treatment or for environmental remediation applications. PMID:28287605

Application of Spectral Gamma Ray for Lithofacies and Paleo-environmental Interpretation: A Case Study from the Late Ordovician Glaciogenic Deposits, Saudi Arabia

NASA Astrophysics Data System (ADS)

Alqubalee, Abdullah; Abdullatif, Osman; Babalola, Lamidi

2017-04-01

This study is an integral part of multidisciplinary research being carried out on the Late Ordovician Sarah Formation in the Rub' Al-Khali Basin, Saudi Arabia. Sarah Formation proved to be important target for tight gas reservoir in Saudi Arabia. This study integrates lithofacies characteristics and spectral Gamma Ray of core samples so as to identify and differentiate among different depositional environments. Thorium (Th, ppm) and potassium (K, %) are acquired with approximately a reading point per inch using high-resolution Spectral Core Gamma. The cores description and analysis from six exploratory wells revealed four depositional environments ranging from the glaciofluvial, glaciolacustrine delta, subglacial to the nearshore environments. Based on lithofacies and geochemical analysis of the core samples, four groups of lithofacies including sandstone (G1), claystone and/or argillaceous sandstone (G2), calcareous and/or evaporitic sandstone (G3), and diamictites (G4) were recognized in each well. The bivariate plots of Th and K were used to delineate the minerals contents in each core and environment. The results showed that the G1 facies of the nearshore and glaciofluvial environments are characterized by similar distribution patterns of these elements exhibiting lower clay minerals variations than that in the other groups of lithofacies. These patterns consist of two mineral groups, the first one includes illite and montmorillonite clay minerals while the second one includes mica, glauconite, and feldspar. By contrast, G1 and G2 lithofacies of the glaciolacustrine delta environment are characterized by a range of clay minerals. However, G3 of this environment exhibits similar pattern of the nearshore and the glaciofluvial environments This is because the grains of G3 are cemented by anhydrite rather than by clays. Based on the lithological characteristic, matrix-supported and clast-supported diamictites were identified in the subglacial environment. The differences between these two lithofacies were clearly detected using Th/K plot. Both diamictites are characterized by a range of minerals including illite, mixed layer clays, glauconite, and feldspar. The matrix-supported diamictites contain higher proportions of these minerals. This study indicates that the relationship between Th and K can be used to predict the types of lithofacies and clay contents in different glaciogenic depositional environments. In addition, it can be used to predict the relative amounts of the clay minerals in each lithofacies. In turn, identifying the types and the amounts of clay minerals in lithofacies facilitate the prediction of reservoir quality and eventually lead to enhancement of their development and productivity.

Interaction between the Bacterium Pseudomonas fluorescens strain CHA0, its genetic derivatives and vermiculite: Effects on chemical, mineralogical and mechanical properties of vermiculite

NASA Astrophysics Data System (ADS)

Mueller, Barbara

2016-04-01

Using bacteria of the strain Pseudomonas fluorescens wild type CHA0 and its genetic derivative strains CHA77, CHA89, CHA400, CHA631 and CHA661 (which differ in one gene only) the changes in chemical, mineralogical and rheological properties of the clay mineral vermiculite affected by microbial activity were studied in order to test whether the individually different production of metabolites by the genetically engineered strains may alter the clay mineral vermiculite in distinct ways. With the novel strategy of working with living wild type bacteria, their genetic derivatives and clay, the following properties of the mineral altered by the various strains of Pseudomonas fluorescens were determined: grain size, X-Ray diffraction pattern, intercrystalline swelling with glycerol, layer charge, CEC, BET surface and uptake of trace elements. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was used to determine the changes in major, minor and trace elements of the clay vermiculite affected by microbial activity. Among all analyzed trace elements, Fe, Mn and Cu are the most interesting. Fe and Mn are taken up from the clay mineral by all bacterial strains whereas Cu is only removed from vermiculite by strains CHA0, CHA77, CHA400 and CHA661. The latter mentioned strains all produce the antibiotics 2,4-diacetylphloroglucinol and monoacetylphloroglucinol which can complex Cu efficiently. Therefore the alteration of only one gene of the bacteria is causing significant effects on the clay mineral.

Diagenetic contrast of sandstones in hydrocarbon prospective Mesozoic rift basins (Ethiopia, UK, USA)

NASA Astrophysics Data System (ADS)

Wolela, A.

2014-11-01

Diagenetic studied in hydrocarbon-prospective Mesozoic rift basins were carried out in the Blue Nile Basin (Ethiopia), Ulster Basin (United Kingdom) and Hartford Basin (United States of America). Alluvial fan, single and amalgamated multistorey meandering and braided river, deep and shallow perennial lake, shallow ephemeral lake, aeolian and playa mud-flat are the prominent depositional environments. The studied sandstones exhibit red bed diagenesis. Source area geology, depositional environments, pore-water chemistry and circulation, tectonic setting and burial history controlled the diagenetic evolution. The diagenetic minerals include: facies-related minerals (calcrete and dolocrete), grain-coating clay minerals and/or hematite, quartz and feldspar overgrowths, carbonate cements, hematite, kaolinite, illite-smectite, smectite, illite, chlorite, actinolite, laumontite, pyrite and apatite. Diversity of diagenetic minerals and sequence of diagenetic alteration can be directly related to depositional environment and burial history of the basins. Variation in infiltrated clays, carbonate cements and clay minerals observed in the studied sandstones. The alluvial fan and fluviatile sandstones are dominated by kaolinite, illite calcite and ferroan calcite, whereas the playa and lacustrine sandstones are dominated by illite-smectite, smectite-chlorite, smectite, chlorite, dolomite ferroan dolomite and ankerite. Albite, pyrite and apatite are predominantly precipitated in lacustrine sandstones. Basaltic eruption in the basins modified mechanically infiltrated clays to authigenic clays. In all the studied sandstones, secondary porosity predominates over primary porosity. The oil emplacement inhabited clay authigenesis and generation of secondary porosity, whereas authigenesis of quartz, pyrite and apatite continued after oil emplacement.

Mineralogical control of soil organic carbon persistence at the multidecadal time scale

NASA Astrophysics Data System (ADS)

Lutfalla, Suzanne; Barré, Pierre; Bernard, Sylvain; Le Guillou, Corentin; Chenu, Claire

2015-04-01

One of the current challenges in understanding the long term persistence of organic carbon in soils is to assess how mineral surfaces, especially at small scale, can stabilize soil organic carbon (SOC). The question we address in this work is whether different mineral species stabilize different types of SOC. Here we used the unique opportunity offered by long term bare fallows to study in situ C dynamics in several fine fractions of a silty loam soil. Indeed, with no vegetation i.e. no external input of fresh C, the plant-free soil of the Versailles 42 Plots (INRA, France) has been progressively enriched in persistent SOC during the 80 years of bare fallow. To separate mineral phases of the clay size fraction we performed a size fractionation on samples taken from 4 different plots at 5 different dates (0, 10, 22, 52, and 79 years after the beginning of the BF) and analyzed the SOC in the different fractions thus obtained. First, the clay fraction (< 2 µm) was isolated by wet sieving and centrifugation in water. Then, the clay fraction was further separated into 3 size fractions by centrifugation: fine clay (< 0.05 µm), intermediate clay (0.05 - 0.2 µm), and coarse clay (0.2 - 2 µm). X-ray diffraction was used to determine the mineralogy of the phases and we found that the coarse clay fraction on the one hand and fine and intermediate clay fractions on the other hand exhibited contrasted mineralogies. Fine and intermediate clay fractions contained almost exclusively smectite and mixed-layered illite/smectite minerals whereas coarse clays contained also discrete illite and kaolinite on top of smectite and illite/smectite. We carried out CHN elemental analysis to study the C and nitrogen dynamics with time in the different fractions. And synchrotron based spectroscopy and microscopy (NEXAFS bulk and STXM at the carbon K edge of 280 eV, CLS Saskatoon, Canada) was used to get information on the distribution and the chemical speciation of the SOC in fractions with contrasted mineralogies. Data analysis is still ongoing and full results will be presented at EGU. First results show that the dynamics and quality of the SOC differ in the different clay fractions. SOC decay was greater in coarse clays compared to intermediate clays, SOC in the coarse clay fraction displaying more diversity than in the other fractions. SOC persistence at the multidecadal timescale also seems to be mineral dependent: smectite being more efficient at protecting carbon compared to illite.

Rainwater as a chemical agent of geologic processes; a review

USGS Publications Warehouse

Carroll, Dorothy

1962-01-01

Chemical analyses of the rainwater collected at several localities are given to show the variations of the principal constitutents. In rock weathering and soil-forming processes, the chemical composition of rainwater has an important effect which has been evaluated for only a few arid areas. In humid regions the important amounts of calcium, magnesium, sodium, and potassium added yearly by rain may be expected to influence the composition of the soil water and thereby the cations in the exchange positions of soil clay minerals. The acquisition of cations by clay minerals may slow down chemical weathering. The stability of soil clay minerals is influenced by the constant accession of cations from rainwater. Conversely, the clay minerals modify the amounts and kinds of cations that are leached out by drainage waters. The stability of micaceous minerals in soils may be partly due to accessions of K +1 ions from rainwater. The pH of rainwater in any area varies considerably and seems to form a seasonal and regional pattern. The recorded pH values range from 3.0 to 9.8.

Synchrotron Powder X-ray Diffraction Study of the Structure and Dehydration Behavior of Sepiolite

NASA Astrophysics Data System (ADS)

Post, J. E.; Bish, D. L.; Heaney, P. J.

2006-05-01

Sepiolite is a hydrous Mg-silicate clay mineral with fibrous morphology that typically occurs as fine-grained, poorly crystalline masses. It occurs in a wide variety of geological environments and has been mined for centuries because of its many uses, e.g. in the pharmaceutical, fertilizer, and pesticide industries. Its versatile functionality derives from the large surface area and microporosity that are characteristic of the material. In recent years, sepiolite has received considerable attention with regard to the adsorption of organics, for use as a support for catalysts, as a molecular sieve, and as an inorganic membrane for ultrafiltration. Because of its fine-grained and poorly crystalline nature, it has not been possible to study sepiolite's crystal structure using single-crystal X-ray diffraction methods, and consequently many details of the structure are still not well known. In this study, Rietveld refinements using synchrotron powder X-ray diffraction data were used to investigate the crystal structure and dehydration behavior of sepiolite from Durango, Mexico. The room- temperature (RT) sepiolite structure in air compares well with previous models but reveals an additional zeolitic water site. The RT structure under vacuum retained only ~1/8 of the zeolitic water and the volume decreased 1.3%. Real-time, temperature-resolved synchrotron powder X-ray diffraction data and Rietveld refinements were used to investigate the behavior of the sepiolite structure from 300 to 925 K. Rietveld refinements revealed that most of the zeolitic water is lost by ~390 K, accompanied by a decrease in the a and c unit-cell parameters. Above ~600 K the sepiolite structure folds as one-half of the crystallographically bound water is lost. Rietveld refinements of the "anhydrous" sepiolite structure reveal that, in general, unit-cell parameters a, b, â and volume steadily decrease with increasing temperature; there is an obvious change in slope at ~820 K suggesting a phase transformation coinciding with the loss of the remaining bound water molecule. These temperature-resolved real-time powder X-ray diffraction studies provide the first comprehensive description of the sepiolite structure and the complex changes it undergoes as it dehydrates. Additional heating and cooling in situ powder X-ray diffraction experiments are underway in order to investigate the relative stabilities and rehydration behaviors of the partially-hydrated sepiolite phases. The results of these studies should provide a more robust model for predicting and modifying the properties and applications of this critical industrial material and environmentally important mineral.

Aluminate effect on desilication product phase transformation

NASA Astrophysics Data System (ADS)

Peng, Hong; Vaughan, James

2018-06-01

It remains a grand challenge in the treatment of bauxite residue to physically separate zeolite (also known as the DeSilication Product, DSP) from other unleached mineral phases owing to their fine sizes, typically less than 2 μm in diameter. In this study, the effect of aluminate concentration on DSP phase transformation was investigated from synthetic NaOH-NaAl(OH)4-Na2SiO3-H2O solution at 90 °C. The results show how at relatively low aluminate concentrations of 0.125 and 0.25 M NaAl(OH)4(aq), larger zeolite crystals of up to 60 μm in diameter are formed during homogenous precipitation from aqueous solution. The precipitation process involves the conversion of zeolite LTA to sodalite via the formation of an intermediate phase, octahedral LTN. Initial amorphous solids precipitate as aggregates in which cubic zeolite LTA nucleation occurs. As the reaction proceeds, truncated octahedral LTN appears with the cubic zeolite LTA and finally sodalite crystallizes on the LTA-LTN aggregates resulting in coarsened particles.

Zeolite A synthesized from alkaline assisted pre-activated halloysite for efficient heavy metal removal in polluted river water and industrial wastewater.

PubMed

Meng, Qingpeng; Chen, Hong; Lin, Junzhong; Lin, Zhang; Sun, Junliang

2017-06-01

High quality zeolite A was synthesized through a hydrothermal process using alkaline-assisted pre-activated halloysite mineral as the alumina and silica source. The synthesis conditions employed in this study were finely tuned by varying the activating temperature, sodium hydroxide content, water content and Si/Al ratio. The obtained zeolite A showed excellent adsorption properties for both single metal cation solutions and mixed cation solutions when the concentrations of the mixed cations were comparable with those in polluted natural river water and industrial wastewater. High adsorptive capacities for Ag + (123.05mg/g) and Pb 2+ (227.70mg/g) were achieved using the synthesized zeolite A. This observation indicates that the zeolite A synthesized from alkaline-assisted pre-activated halloysite can be used as a low-cost and relatively effective adsorbent to purify heavy metal cation polluted natural river water and industrial wastewater. Copyright © 2016. Published by Elsevier B.V.

Correlation between thermal behavior of clays and their chemical and mineralogical composition: a review

NASA Astrophysics Data System (ADS)

Dwi Yanti, Evi; Pratiwi, I.

2018-02-01

Clay's abundance has been widely used as industrial raw materials, especially ceramic and tile industries. Utilization of these minerals needs a thermal process for producing ceramic products. Two studies conducted by Septawander et al. and Chin C et al., showed the relationship between thermal behavior of clays and their chemical and mineralogical composition. Clays are characterized by XRD analysis and thermal analysis, ranging from 1100°C to 1200°C room temperature. Specimen of raw materials of clay which is used for the thermal treatment is taken from different geological conditions and formation. In raw material, Quartz is almost present in all samples. Halloysite, montmorillonite, and feldspar are present in Tanjung Morawa raw clay. KC and MC similar kaolinite and illite are present in the samples. The research illustrates the interrelationships of clay minerals and chemical composition with their heat behavior. As the temperature of combustion increases, the sample reduces a significant weight. The minerals which have undergone a transformation phase became mullite, cristobalite or illite and quartz. Under SEM analysis, the microstructures of the samples showed irregularity in shape; changes occurred due the increase of heat.

Multidecadal persistence of organic matter in soils: insights from spatially resolved investigations at the submicrometer scale

NASA Astrophysics Data System (ADS)

Lutfalla, Suzanne; Barré, Pierre; Bernard, Sylvain; Le Guillou, Corentin; Alléon, Julien; Chenu, Claire

2016-04-01

Better understanding the mechanisms responsible for the pluri-decadal persistence of carbon in soils requires well constraining the dynamics, the distribution and the chemical nature of both the soil organic carbon (SOC) and the associated mineral phases. The question we address in this work is whether different mineral species lead to different organo-mineral interactions and stabilize different quantities of SOM and different types of SOC. Here, benefiting from the unique opportunity offered by an INRA long term bare fallow (LTBF) experiment having started in 1928 in Versailles (France), we report the in-situ characterization of SOC dynamics in four clay fractions of this silty loam soil (total clays [TC, <2μm], coarse clays [CC, 0.2-2μm], intermediate clays [IC, 0.05-0.2μm] and fine clays [FC, 0-0.05μm]). The IC and FC fractions only contain smectite and illite/smectite mixed-layered clay minerals while the CC fraction also contains illite and kaolinite. In the absence of any carbon input, the plant-free LTBF clay fractions from Versailles progressively lost SOC during the first 50 years of the experiment, until they reached a seemingly stable concentration. Of note, the investigated clay fractions did not lose the same amount of SOC and do not exhibit the same final carbon concentrations. The decrease of the organic C:N ratios with LTBF duration corresponds to a progressive enrichment in N-rich SOC for all fractions which can be attributed to microbial material. Even though the speciation of SOC appears to only slightly evolve with LTBF duration, an enrichment in carboxyl and carbonyl groups is revealed by bulk-scale C-NEXAFS data for SOC from all clay fractions. In addition, STXM-based NEXAFS investigations at the submicrometer scale reveal three types of SOC-clay assemblages in addition to clay-free SOC and organic-free clays. While SOC appears mostly adsorbed onto clay surfaces within the IC and FC fractions, other protection mechanisms occur within the CC fraction. Altogether, the present study suggests that smectite have more efficient protection capabilities than those of illite and kaolinite.

Reactivity of clay minerals with acids and alkalies

USGS Publications Warehouse

Carroll, Dorothy; Starkey, Harry C.

1971-01-01

One-g samples of a montmorillonite, a metabentonite, an illite, two kaolinites, and three halloysites were treated with 50 ml of hydrochloric acid (6⋅45 N, 1:1), acetic acid (4⋅5 N, 1:3), sodium hydroxide (2⋅8 N), sodium chloride solution (pH 6⋅10; Na = 35‰; Cl = 21⋅5‰), and natural sea water (pH 7⋅85; Na = 35⋅5‰; Cl = 21⋅ 5‰) for a 10-day period in stoppered plastic vials. The supernatant solutions were removed from the clay minerals and analyzed for SiO2, Al2O3, CaO, MgO, Na2O, and K2O. All the solutions removed some SiO2, Al2O3, and Fe2O3 from the samples, but the quantities were small. Sodium hydroxide attacked the kaolin group minerals more strongly than it did montmorillonite, metabentonite, or illite. Halloysite was more strongly attacked by hydrochloric acid than was any of the other experimental minerals. Hydrochloric acid removed iron oxide coatings from soil clay minerals, but acetic acid did not remove them completely. The samples most strongly attacked by HCl and NaOH were examined by X-ray diffraction. Acid treatment did not destroy the structure of the clays, but the halloysite structure was partially destroyed. Sodium hydroxide attacked the halloysite structure, as shown by chemical analysis and X-ray diffraction. These experiments show that treatment in dilute acids has no harmful effect in the preparation of clays for X-ray diffraction. Acetic acid is preferred to hydrochloric acid for this purpose. Hydrochloric acid cleans clay minerals by removing free iron oxide from the surface; acetic acid is less effective.

Clay mineralogy of surface sediments as a tool for deciphering river contributions to the Cariaco Basin (Venezuela)

NASA Astrophysics Data System (ADS)

Bout-Roumazeilles, V.; Riboulleau, A.; du Châtelet, E. Armynot; Lorenzoni, L.; Tribovillard, N.; Murray, R. W.; Müller-Karger, F.; Astor, Y. M.

2013-02-01

The mineralogical composition of 95 surface sediment samples from the Cariaco Basin continental shelf and Orinoco delta was investigated in order to constrain the clay-mineral main provenance and distribution within the Cariaco Basin. The spatial variability of the data set was studied using a geo-statistical approach that allows drawing representative clay-mineral distribution maps. These maps are used to identify present-day dominant sources for each clay-mineral species in agreement with the geological characteristics of the main river watersheds emptying into the basin. This approach allows (1) identifying the most distinctive clay-mineral species/ratios that determine particle provenance, (2) evaluating the respective contribution of local rivers, and (3) confirming the minimal present-day influence of the Orinoco plume on the Cariaco Basin sedimentation. The Tuy, Unare, and Neveri Rivers are the main sources of clay particles to the Cariaco Basin sedimentation. At present, the Tuy River is the main contributor of illite to the western part of the southern Cariaco Basin continental shelf. The Unare River plume, carrying smectite and kaolinite, has a wide westward propagation, whereas the Neveri River contribution is less extended, providing kaolinite and illite toward the eastern Cariaco Basin. The Manzanares, Araya, Tortuga, and Margarita areas are secondary sources of local influence. These insights shed light on the origin of present-day terrigenous sediments of the Cariaco Basin and help to propose alternative explanations for the temporal variability of clay mineralogy observed in previously published studies.

INTERACTIONS OF METHYL ORANGE WITH CYCLODEXTRIN/SODIUM-MONTMORILLONITE SYSTEMS PROBED BY UV-VISIBLE SPECTROSCOPY

EPA Science Inventory

Clay mineral colloids play important roles in the adsorption of polar organic contaminants in the environment. Similarly, cyclodextrins (CD) can entrap poorly water-soluble organic compounds. A combination of CDs and clay minerals affords great opportunities to investigate simult...

Clay mineral diversity and abundance in sedimentary rocks of Gale crater, Mars

PubMed Central

Chipera, Steve J.; Hazen, Robert M.; Horgan, Briony; Hogancamp, Joanna V.; Mangold, Nicolas; Morookian, John Michael; Morris, Richard V.; Vaniman, David T.; Yen, Albert S.

2018-01-01

Clay minerals provide indicators of the evolution of aqueous conditions and possible habitats for life on ancient Mars. Analyses by the Mars Science Laboratory rover Curiosity show that ~3.5–billion year (Ga) fluvio-lacustrine mudstones in Gale crater contain up to ~28 weight % (wt %) clay minerals. We demonstrate that the species of clay minerals deduced from x-ray diffraction and evolved gas analysis show a strong paleoenvironmental dependency. While perennial lake mudstones are characterized by Fe-saponite, we find that stratigraphic intervals associated with episodic lake drying contain Al-rich, Fe3+-bearing dioctahedral smectite, with minor (3 wt %) quantities of ferripyrophyllite, interpreted as wind-blown detritus, found in candidate aeolian deposits. Our results suggest that dioctahedral smectite formed via near-surface chemical weathering driven by fluctuations in lake level and atmospheric infiltration, a process leading to the redistribution of nutrients and potentially influencing the cycling of gases that help regulate climate. PMID:29881776

Synthetic Zeolites as Controlled-Release Delivery Systems for Anti-Inflammatory Drugs.

PubMed

Khodaverdi, Elham; Soleimani, Hossein Ali; Mohammadpour, Fatemeh; Hadizadeh, Farzin

2016-06-01

Scientists have always been trying to use artificial zeolites to make modified-release drug delivery systems in the gastrointestinal tract. An ideal carrier should have the capability to release the drug in the intestine, which is the main area of absorption. Zeolites are mineral aluminosilicate compounds with regular structure and huge porosity, which are available in natural and artificial forms. In this study, soaking, filtration and solvent evaporation methods were used to load the drugs after activation of the zeolites. Weight measurement, spectroscopy FTIR, thermogravimetry and scanning electronic microscope were used to determine drug loading on the systems. Finally, consideration of drug release was made in a simulated gastric fluid and a simulated intestinal fluid for all matrixes (zeolites containing drugs) and drugs without zeolites. Diclofenac sodium (D) and piroxicam (P) were used as the drug models, and zeolites X and Y as the carriers. Drug loading percentage showed that over 90% of drugs were loaded on zeolites. Dissolution tests in stomach pH environment showed that the control samples (drug without zeolite) released considerable amount of drugs (about 90%) within first 15 min when it was about 10-20% for the matrixes. These results are favorable as NSAIDs irritate the stomach wall and it is ideal not to release much drugs in the stomach. Furthermore, release rate of drugs from matrixes has shown slower rate in comparison with control samples in intestine pH environment. © 2016 John Wiley & Sons A/S.

Zeolite food supplementation reduces abundance of enterobacteria.

PubMed

Prasai, Tanka P; Walsh, Kerry B; Bhattarai, Surya P; Midmore, David J; Van, Thi T H; Moore, Robert J; Stanley, Dragana

2017-01-01

According to the World Health Organisation, antibiotics are rapidly losing potency in every country of the world. Poultry are currently perceived as a major source of pathogens and antimicrobial resistance. There is an urgent need for new and natural ways to control pathogens in poultry and humans alike. Porous, cation rich, aluminosilicate minerals, zeolites can be used as a feed additive in poultry rations, demonstrating multiple productivity benefits. Next generation sequencing of the 16S rRNA marker gene was used to phylogenetically characterize the fecal microbiota and thus investigate the ability and dose dependency of zeolite in terms of anti-pathogenic effects. A natural zeolite was used as a feed additive in laying hens at 1, 2, and 4% w/w for a 23 week period. At the end of this period cloacal swabs were collected to sample faecal microbial communities. A significant reduction in carriage of bacteria within the phylum Proteobacteria, especially in members of the pathogen-rich family Enterobacteriaceae, was noted across all three concentrations of zeolite. Zeolite supplementation of feed resulted in a reduction in the carriage of a number of poultry pathogens without disturbing beneficial bacteria. This effect was, in some phylotypes, correlated with the zeolite concentration. This result is relevant to zeolite feeding in other animal production systems, and for human pathogenesis. Copyright © 2016 Elsevier GmbH. All rights reserved.

Bioavailability of iron in geophagic earths and clay minerals, and their effect on dietary iron absorption using an in vitro digestion/Caco-2 cell model.

PubMed

Seim, Gretchen L; Ahn, Cedric I; Bodis, Mary S; Luwedde, Flavia; Miller, Dennis D; Hillier, Stephen; Tako, Elad; Glahn, Raymond P; Young, Sera L

2013-08-01

Geophagy, the deliberate consumption of earth, is strongly associated with iron (Fe) deficiency. It has been proposed that geophagy may be practiced as a means to improve Fe status by increasing Fe intakes and, conversely, that geophagy may cause Fe deficiency by inhibiting Fe absorption. We tested these hypotheses by measuring Fe concentration and relative bioavailable Fe content of 12 samples of geophagic earth and 4 samples of pure clay minerals. Further, we assessed the impact of these samples on the bioavailability of Fe from an Fe-rich test meal (cooked white beans, WB). Fe concentrations were measured with inductively coupled plasma atomic emission spectroscopy. Fe bioavailability was determined using an in vitro digestion/Caco-2 cell model in which ferritin formation was used as an index of Fe bioavailability. Geophagic earth and clay mineral samples were evaluated with this model, both alone and in combination with WB (1 : 16 ratio, sample : WB). Median Fe concentration of the geophagic earth was 3485 (IQR 2462, 14 ,571) μg g⁻¹ and mean Fe concentration in the clay minerals was 2791 (±1782) μg g⁻¹. All specimens had Fe concentrations significantly higher (p ≤ 0.005) than the Fe concentration of WB (77 μg g⁻¹). Ferritin formation (i.e. Fe uptake) in cells exposed to geophagic earths and clay minerals was significantly lower than in cells exposed to WB (p ≤ 0.05) and Fe uptake responses of 11 of the 16 samples were not significantly different from the blank, indicating no bioavailable Fe. When samples were combined with WB, 5 of 16 had mean ferritin levels that were significantly lower (p ≤ 0.05, one tail) than the WB alone, indicating that the samples inhibited Fe uptake from the WB. None of the ferritin responses of cells exposed to both WB and earth/clay were significantly higher than WB alone. Thus, although geophagic earths and mineral clays are high in total Fe, very little of this Fe is bioavailable. Further, some geophagic earth and clay mineral samples inhibit Fe absorption from foods. In vivo research is warranted to confirm these observations and to determine if geophagic earth samples can be a source of Fe and/or inhibit Fe absorption.

Bioavailability of iron in geophagic earths and clay minerals, and their effect on dietary iron absorption using an in vitro digestion/Caco-2 cell model

PubMed Central

Seim, Gretchen L.; Ahn, Cedric I.; Bodis, Mary S.; Luwedde, Flavia; Miller, Dennis D.; Hillier, Stephen; Tako, Elad; Glahn, Raymond P.; Young, Sera L.

2014-01-01

Geophagy, the deliberate consumption of earth, is strongly associated with iron (Fe) deficiency. It has been proposed that geophagy may be practiced as a means to improve Fe status by increasing Fe intakes and, conversely, that geophagy may cause Fe deficiency by inhibiting Fe absorption. We tested these hypotheses by measuring Fe concentration and relative bioavailable Fe content of 12 samples of geophagic earth and 4 samples of pure clay minerals. Further, we assessed the impact of these samples on the bioavailability of Fe from an Fe-rich test meal (cooked white beans, WB). Fe concentrations were measured with inductively coupled plasma atomic emission spectroscopy. Fe bioavailability was determined using an in vitro digestion/Caco-2 cell model in which ferritin formation was used as an index of Fe bioavailability. Geophagic earth and clay mineral samples were evaluated with this model, both alone and in combination with WB (1:16 ratio, sample:WB). Median Fe concentration of the geophagic earth was 3485 (IQR 2462, 14571) μg/g and mean Fe concentration in the clay minerals was 2791 (± 1782) μg/g. All specimens had Fe concentrations significantly higher (p ≤ 0.005) than the Fe concentration of WB (77 μg/g). Ferritin formation (i.e. Fe uptake) in cells exposed to geophagic earths and clay minerals was significantly lower than in cells exposed to WB (p ≤ 0.05) and Fe uptake responses of 11 of the 16 samples were not significantly different from the blank, indicating no bioavailable Fe. When samples were combined with WB, 5 of 16 had mean ferritin levels that were significantly lower (p ≤ 0.05, one tail) than the WB alone, indicating that the samples inhibited Fe uptake from the WB. None of the ferritin responses of cells exposed to both WB and earth/clay were significantly higher than WB alone. Thus, although geophagic earths and mineral clays are high in total Fe, very little of this Fe is bioavailable. Further, some geophagic earth and clay mineral samples inhibit Fe absorption from foods. In vivo research is warranted to confirm these observations and to determine if geophagic earth samples can be a source of Fe and/or inhibit Fe absorption. PMID:23787405

Biochemical evolution. I. Polymerization on internal, organophilic silica surfaces of dealuminated zeolites and feldspars

PubMed Central

Smith, Joseph V.

1998-01-01

Catalysis at mineral surfaces might generate replicating biopolymers from simple chemicals supplied by meteorites, volcanic gases, and photochemical gas reactions. Many ideas are implausible in detail because the proposed mineral surfaces strongly prefer water and other ionic species to organic ones. The molecular sieve silicalite (Union Carbide; = Al-free Mobil ZSM-5 zeolite) has a three-dimensional, 10-ring channel system whose electrically neutral Si-O surface strongly adsorbs organic species over water. Three -O-Si tetrahedral bonds lie in the surface, and the fourth Si-O points inwards. In contrast, the outward Si-OH of simple quartz and feldspar crystals generates their ionic organophobicity. The ZSM-5-type zeolite mutinaite occurs in Antarctica with boggsite and tschernichite (Al-analog of Mobil Beta). Archean mutinaite might have become de-aluminated toward silicalite during hot/cold/wet/dry cycles. Catalytic activity of silicalite increases linearly with Al-OH substitution for Si, and Al atoms tend to avoid each other. Adjacent organophilic and catalytic Al-OH regions in nanometer channels might have scavenged organic species for catalytic assembly into specific polymers protected from prompt photochemical destruction. Polymer migration along weathered silicic surfaces of micrometer-wide channels of feldspars might have led to assembly of replicating catalytic biomolecules and perhaps primitive cellular organisms. Silica-rich volcanic glasses should have been abundant on the early Earth, ready for crystallization into zeolites and feldspars, as in present continental basins. Abundant chert from weakly metamorphosed Archaean rocks might retain microscopic clues to the proposed mineral adsorbent/catalysts. Other framework silicas are possible, including ones with laevo/dextro one-dimensional channels. Organic molecules, transition-metal ions, and P occur inside modern feldspars. PMID:9520372

Date palm waste-derived biochar composites with silica and zeolite: synthesis, characterization and implication for carbon stability and recalcitrant potential.

PubMed

Ahmad, Munir; Ahmad, Mahtab; Usman, Adel R A; Al-Faraj, Abdullah S; Abduljabbar, Adel; Ok, Yong Sik; Al-Wabel, Mohammad I

2017-03-23

Engineered organo-mineral composites were synthesized from date palm waste biochar and silica or zeolite via mechanochemical treatments. Date palm tree rachis (leaves) waste biomass was pre-treated with silica or zeolite minerals via ball milling and sonication prior to pyrolysis at 600 °C. The resultant organo-mineral composites and pristine materials were characterized using X-ray diffraction, thermogravimetric-differential thermal (TG-DTA), Fourier transform infrared, scanning electron microscope analyses and surface area and porosity analyzer to investigate the variations in physiochemical and structural characteristics. Compared to the resultant composites derived from non-milled date palm biomass, ball milling increased surface area, while decreased crystallinity index and effective particle size of the biochar composites. Silica composited biochars were located near origin in the van Krevelen diagram indicating lowest H/C and O/C molar ratios, thus suggesting higher aromaticity and lower polarity compared to other biochars. TGA thermograms indicated highest thermal stability of silica composited biochars. Ash and moisture corrected TGA thermograms were used to calculate recalcitrance index (R 50 ) of the materials, which speculated high degradability of biomass (R 50  < 0.4), minimal degradability of biochars and zeolite composited biochars (0.5 < R 50  < 0.7) and high recalcitrant nature of silica composited biochars (R 50  > 0.7). Silica composited biochars exhibited highest carbon sequestration potential (64.17-95.59%) compared to other biochars. Highest recalcitrance and carbon sequestration potential of silica composited biochars may be attributed to changes in structural arrangements in the silica-biochar complex. Encapsulations of biochar particles with amorphous silica via Si-C bonding may have prevented thermal degradation, subsequently increasing recalcitrance potential of silica composited biochars.

Biochemical evolution. I. Polymerization On internal, organophilic silica surfaces of dealuminated zeolites and feldspars.

PubMed

Smith, J V

1998-03-31

Catalysis at mineral surfaces might generate replicating biopolymers from simple chemicals supplied by meteorites, volcanic gases, and photochemical gas reactions. Many ideas are implausible in detail because the proposed mineral surfaces strongly prefer water and other ionic species to organic ones. The molecular sieve silicalite (Union Carbide; = Al-free Mobil ZSM-5 zeolite) has a three-dimensional, 10-ring channel system whose electrically neutral Si-O surface strongly adsorbs organic species over water. Three -O-Si tetrahedral bonds lie in the surface, and the fourth Si-O points inwards. In contrast, the outward Si-OH of simple quartz and feldspar crystals generates their ionic organophobicity. The ZSM-5-type zeolite mutinaite occurs in Antarctica with boggsite and tschernichite (Al-analog of Mobil Beta). Archean mutinaite might have become de-aluminated toward silicalite during hot/cold/wet/dry cycles. Catalytic activity of silicalite increases linearly with Al-OH substitution for Si, and Al atoms tend to avoid each other. Adjacent organophilic and catalytic Al-OH regions in nanometer channels might have scavenged organic species for catalytic assembly into specific polymers protected from prompt photochemical destruction. Polymer migration along weathered silicic surfaces of micrometer-wide channels of feldspars might have led to assembly of replicating catalytic biomolecules and perhaps primitive cellular organisms. Silica-rich volcanic glasses should have been abundant on the early Earth, ready for crystallization into zeolites and feldspars, as in present continental basins. Abundant chert from weakly metamorphosed Archaean rocks might retain microscopic clues to the proposed mineral adsorbent/catalysts. Other framework silicas are possible, including ones with laevo/dextro one-dimensional channels. Organic molecules, transition-metal ions, and P occur inside modern feldspars.

The ultimate mineral processing challenge: Recovery of rare earths, phosphorus and uranium from Florida phosphatic clay

DOE PAGES

Zhang, Patrick; Liang, Haijun; Jin, Zhen; ...

2017-11-01

We report phosphate beneficiation in Florida generates more than one tonne of phosphatic clay, or slime, per tonne of phosphate rock produced. Since the start of the practice of large-scale washing and desliming for phosphate beneficiation, more than 2 Gt of slime has accumulated, containing approximately 600 Mt of phosphate rock, 600 kt of rare earth elements (REEs) and 80 million kilograms of uranium. The recovery of these valuable elements from the phosphatic clay is one of the most challenging endeavors in mineral processing, because the clay is extremely dilute, with an average solids concentration of 3 percent, and finemore » in size, with more than 50 percent having particle size smaller than 2 μm, and it contains nearly 50 percent clay minerals as well as large amounts of magnesium, iron and aluminum. With industry support and under funding from the Critical Materials Institute, the Florida Industrial and Phosphate Research Institute in conjunction with the Oak Ridge National Laboratory undertook the task to recover phosphorus, rare earths and uranium from Florida phosphatic clay. This paper presents the results from the preliminary testing of two approaches. The first approach involves three-stage cycloning using cyclones with diameters of 12.4 cm (5 in.), 5.08 cm (2 in.) and 2.54 cm (1 in.), respectively, to remove clay minerals followed by flotation and leaching. The second approach is a two-step leaching process. In the first step, selective leaching was conducted to remove magnesium, thus allowing the production of phosphoric acid suitable for the manufacture of diammonium phosphate (DAP) in the second leaching step. The results showed that multistage cycloning with small cyclones is necessary to remove clay minerals. Finally, selective leaching at about pH 3.2 using sulfuric acid was found to be effective for removing more than 80 percent of magnesium from the feed with minimal loss of phosphorus.« less

The ultimate mineral processing challenge: Recovery of rare earths, phosphorus and uranium from Florida phosphatic clay

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Patrick; Liang, Haijun; Jin, Zhen

We report phosphate beneficiation in Florida generates more than one tonne of phosphatic clay, or slime, per tonne of phosphate rock produced. Since the start of the practice of large-scale washing and desliming for phosphate beneficiation, more than 2 Gt of slime has accumulated, containing approximately 600 Mt of phosphate rock, 600 kt of rare earth elements (REEs) and 80 million kilograms of uranium. The recovery of these valuable elements from the phosphatic clay is one of the most challenging endeavors in mineral processing, because the clay is extremely dilute, with an average solids concentration of 3 percent, and finemore » in size, with more than 50 percent having particle size smaller than 2 μm, and it contains nearly 50 percent clay minerals as well as large amounts of magnesium, iron and aluminum. With industry support and under funding from the Critical Materials Institute, the Florida Industrial and Phosphate Research Institute in conjunction with the Oak Ridge National Laboratory undertook the task to recover phosphorus, rare earths and uranium from Florida phosphatic clay. This paper presents the results from the preliminary testing of two approaches. The first approach involves three-stage cycloning using cyclones with diameters of 12.4 cm (5 in.), 5.08 cm (2 in.) and 2.54 cm (1 in.), respectively, to remove clay minerals followed by flotation and leaching. The second approach is a two-step leaching process. In the first step, selective leaching was conducted to remove magnesium, thus allowing the production of phosphoric acid suitable for the manufacture of diammonium phosphate (DAP) in the second leaching step. The results showed that multistage cycloning with small cyclones is necessary to remove clay minerals. Finally, selective leaching at about pH 3.2 using sulfuric acid was found to be effective for removing more than 80 percent of magnesium from the feed with minimal loss of phosphorus.« less

Aggregation and stability of anisotropic charged clay colloids in aqueous medium in the presence of salt.

PubMed

Ali, Samim; Bandyopadhyay, Ranjini

2016-01-01

Na-montmorillonite nanoclay is a colloid of layered mineral silicate. When dispersed in water, this mineral swells on absorption of water and exfoliates into platelets with electric double layers on their surfaces. Even at low particle concentration, the aqueous dispersion can exhibit a spontaneous ergodicity breaking phase transition from a free flowing liquid to nonequilibrium, kinetically arrested and disordered states such as gels and glasses. In an earlier publication [Applied Clay Science, 2015, 114, 8592], we showed that the stability of clay gels can be enhanced by adding a salt later to the clay dispersion prepared in deionized water, rather than by adding the clay mineral to a previously mixed salt solution. Here, we directly track the collapsing interface of sedimenting clay gels using an optical method and show that adding salt after dispersing the clay mineral does indeed result in more stable gels even in very dilute dispersions. These weak gels are seen to exhibit a transient collapse after a finite delay time, a phenomenon observed previously in depletion gels. The velocity of the collapse oscillates with the age of the sample. However, the average velocity of collapse increases with sample age up to a peak value before decreasing at higher ages. With increasing salt concentration, the delay time for transient collapse decreases, while the peak value of the collapsing velocity increases. Using ultrasound attenuation spectroscopy, rheometry and cryogenic scanning electron microscopy, we confirm that morphological changes of the gel network assembly, facilitated by thermal fluctuations, lead to the observed collapse phenomenon. Since clay minerals are used extensively in polymer nanocomposites, as rheological modifiers, stabilizers and gas absorbents, we believe that the results reported in this work are extremely useful for several practical applications and also for understanding geophysical phenomena such as the formation and stability of quicksand and river deltas.

Color measurement of methylene blue dye/clay mixtures and its application using economical methods

NASA Astrophysics Data System (ADS)

Milosevic, Maja; Kaludjerovic, Lazar; Logar, Mihovil

2016-04-01

Identifying the clay mineral components of clay materials by staining tests is rapid and simple, but their applicability is restricted because of the mutual interference of the common components of clay materials and difficulties in color determination. The change of color with concentration of the dye is related to the use of colorants as a field test for identifying clay minerals and has been improved over the years to assure the accuracy of the tests (Faust G. T., 1940). The problem of measurement and standardization of color may be solved by combination of colors observed in staining tests with prepared charts of color chips available in the Munsell Book of Color, published by Munsell Color Co. Under a particular set of illumination conditions, a human eye can achieve an approximate match between the color of the dyed clay sample and that of a standard color chip, even though they do have different spectral reflectance characteristics. Experiments were carried out with diffuse reflectance spectroscopy on selected clay samples (three montmorillonite, three kaolinite and one mix-layer clay samples) saturated with different concentration of methylene blue dye solution. Dominant wavelength and purity of the color was obtained on oriented dry samples and calculated by use of the I. C. I. (x, y) - diagram in the region of 400-700 nm (reflectance spectra) without MB and after saturation with different concentrations of MB solutions. Samples were carefully photographed in the natural light environment and processed with user friendly and easily accessible applications (Adobe color CC and ColorHexa encyclopedia) available for android phones or tablets. Obtained colors were compared with Munsell standard color chips, RGB and Hexa color standards. Changes in the color of clay samples in their interaction with different concentration of the applied dye together with application of economical methods can still be used as a rapid fieldwork test. Different types of clay minerals can be distinguished by application of at least three concentrations of the methylene blue dye on the same sample and observing the color change in comparison with standardized color chips that can be easily obtained and free of charge. If the color tests are properly used in conjunction with other more complex analytical procedures, they can be helpful addition in identification of different clay minerals, especially montmorillonite and kaolinite minerals. - Faust G. T., 1940, Staining of clay minerals as a rapid means of identification in natural and beneficiated products, U. S. Bur. Mines, Investigation Report. N0.3522 - Munsell Color, Munsell Book of Color, 1942. Macbeth Division of Kollmorgen Corporation, Maryland, U.S.A. - https://color.adobe.com/create/color-wheel/ - http://www.colorhexa.com/

Zeolitization of intracaldera sediments and rhyolitic rocks in the 1.25 Ma lake of Valles caldera, New Mexico, USA

NASA Astrophysics Data System (ADS)

Chipera, Steve J.; Goff, Fraser; Goff, Cathy J.; Fittipaldo, Melissa

2008-12-01

Quantitative X-ray diffraction analysis of about 80 rhyolite and associated lacustrine rocks has characterized previously unrecognized zeolitic alteration throughout the Valles caldera resurgent dome. The alteration assemblage consists primarily of smectite-clinoptilolite-mordenite-silica, which replaces groundmass and fills voids, especially in the tuffs and lacustrine rocks. Original rock textures are routinely preserved. Mineralization typically extends to depths of only a few tens of meters and resembles shallow "caldera-type zeolitization" as defined by Utada et al. [Utada, M., Shimizu, M., Ito, T., Inoue, A., 1999. Alteration of caldera-forming rocks related to the Sanzugawa volcanotectonic depression, northeast Honshu, Japan — with special reference to "caldera-type zeolitization." Resource Geol. Spec. Issue No. 20, 129-140]. Geology and 40Ar/ 39Ar dates limit the period of extensive zeolite growth to roughly the first 30 kyr after the current caldera formed (ca. 1.25 to 1.22 Ma). Zeolitic alteration was promoted by saturation of shallow rocks with alkaline lake water (a mixture of meteoric waters and degassed hydrothermal fluids) and by high thermal gradients caused by cooling of the underlying magma body and earliest post-caldera rhyolite eruptions. Zeolitic alteration of this type is not found in the later volcanic and lacustrine rocks of the caldera moat (≤ 0.8 Ma) suggesting that later lake waters were cooler and less alkaline. The shallow zeolitic alteration does not have characteristics resembling classic, alkaline lake zeolite deposits (no analcime, erionite, or chabazite) nor does it contain zeolites common in high-temperature hydrothermal systems (laumontite or wairakite). Although aerially extensive, the early zeolitic alteration does not form laterally continuous beds and are consequently, not of economic significance.

Modification of zeolite 4A for use as an adsorbent for glyphosate and as an antibacterial agent for water.

PubMed

Zavareh, Siamak; Farrokhzad, Zahra; Darvishi, Farshad

2018-07-15

The aim of this work was to design a low cost adsorbent for efficient and selective removal of glyphosate from water at neutral pH conditions. For this purpose, zeolite 4A, a locally abundant and cheap mineral material, was ion-exchanged with Cu 2+ to produce Cu-zeolite 4A. The FTIR results revealed that the modification has no important effect on chemical structure of zeolite 4A. After modification, highly crystalline zeolite 4A was converted to amorphous Cu-zeolite 4A according to XRD studies. The SEM images showed spherical-like particles with porous surfaces for Cu-zeolite 4A compared to cubic particles with smooth surfaces for zeolite 4A. Adsorption equilibrium data were well fitted with non-linear forms of Langmuir, Freundlich and Temkin isotherms. The maximum adsorption capacity for Cu-zeolite 4A was calculated to be 112.7 mg g -1 based on the Langmuir model. The adsorption of glyphosate by the modified adsorbent had fast kinetics fitted both pseudo-first-order and pseudo-second-order models. A mechanism based on chemical adsorption was proposed for the removal process. The modified adsorbent had a good selectivity to glyphosate over natural waters common cations and anions. It also showed desired regeneration ability as an important feature for practical uses. The potential use of the developed material as antibacterial agent for water disinfection filters was also investigated by MIC method. Relatively strong antibacterial activity was observed for Cu-zeolite 4A against Gram-positive and Gram-negative model bacteria while zeolite 4A had no antibacterial properties. No release of Cu 2+ to aqueous solutions was detected as unique feature of the developed material. Copyright © 2018 Elsevier Inc. All rights reserved.

Microsphere zeolite materials derived from coal fly ash cenospheres as precursors to mineral-like aluminosilicate hosts for 135,137Cs and 90Sr

NASA Astrophysics Data System (ADS)

Vereshchagina, Tatiana A.; Vereshchagin, Sergei N.; Shishkina, Nina N.; Vasilieva, Nataly G.; Solovyov, Leonid A.; Anshits, Alexander G.

2013-06-01

Hollow microsphere zeolite materials with a bilayered zeolite/glass crystalline shell bearing NaP1 zeolite were synthesized by the hydrothermal treatment of coal fly ash cenospheres (Si/Al = 2.7) in an alkaline medium. Cs+ and/or Sr2+ forms of zeolitized cenospheres with the different Cs+ and/or Sr2+ loading were prepared by the ion exchange from nitrate solutions. The resulted (Cs,Na)P1, (Sr,Na)P1 and (Cs,Sr,Na)P1 bearing microsphere zeolites were converted to glass ceramics by heating at 900-1000 °C. The differential scanning calorimetry and quantitative phase analysis were used to monitor the solid-phase transformation of the initial and ion exchanged zeolite materials. It was established that the final solidified forms of Cs+ and/or Sr2+ are glass-crystalline ceramic materials based on pollucite-nepheline, Sr-feldspar-nepheline and Sr-feldspar-pollucite composites including ˜60 wt.% of the major host phases (pollucite, Sr-feldspar) and 10-20 wt.% of glass. The 137Cs leaching rate of 4.1 × 10-7 g cm-2 day-1 was determined for the pollucite glass-ceramic according to Russian State Standard (GOST) No. 52126 P-2003 (7 day, 25 °C, distilled water).

The role of clay minerals in the preservation of organic matter in sediments of Qinghai Lake, NW China

USGS Publications Warehouse

Yu, Bingsong; Dong, Hailiang; Jiang, Hongchen; Lv, Guo; Eberl, Dennis D.; Li, Shanying; Kim, Jinwook

2009-01-01

The role of saline lake sediments in preserving organic matter has long been recognized. In order to further understand the preservation mechanisms, the role of clay minerals was studied. Three sediment cores, 25, 57, and 500 cm long, were collected from Qinghai Lake, NW China, and dissected into multiple subsamples. Multiple techniques were employed, including density fractionation, X-ray diffraction, scanning and transmission electron microscopy (SEM and TEM), total organic carbon (TOC) and carbon compound analyses, and surface area determination. The sediments were oxic near the water-sediment interface, but became anoxic at depth. The clay mineral content was as much as 36.8%, consisting mostly of illite, chlorite, and halloysite. The TEM observations revealed that organic matter occurred primarily as organic matter-clay mineral aggregates. The TOC and clay mineral abundances are greatest in the mid-density fraction, with a positive correlation between the TOC and mineral surface area. The TOC of the bulk sediments ranges from 1 to 3% with the non-hydrocarbon fraction being predominant, followed by bitumen, saturated hydrocarbon, aromatic hydrocarbons, and chloroform-soluble bitumen. The bimodal distribution of carbon compounds of the saturated hydrocarbon fraction suggests that organic matter in the sediments was derived from two sources: terrestrial plants and microorganisms/algae. Depthrelated systematic changes in the distribution patterns of the carbon compounds suggest that the oxidizing conditions and microbial abundance near the water-sediment interface promote degradation of labile organic matter, probably in adsorbed form. The reducing conditions and small microbial biomass deeper in the sediments favor preservation of organic matter, because of the less labile nature of organic matter, probably occurring within clay mineral-organic matter aggregates that are inaccessible to microorganisms. These results have important implications for our understanding of mechanisms of organic matter preservation in saline lake sediments.

Removal of Chromium from Soils Cultivated with Maize (Zea Mays) After the Addition of Natural Minerals as Soil Amendments.

PubMed

Μolla, A; Ioannou, Z; Mollas, S; Skoufogianni, E; Dimirkou, A

2017-03-01

The efficiency of natural minerals, i.e. zeolite, bentonite and goethite, regarding the retention of chromium, from maize was examined. Specifically, 1.0 kg of soil, 1.0 g of soil amendment and either 50 mg L -1 Cr(III) or 1 mg L -1 Cr(VI) were added in plant pots. Then, seeds of maize were cultivated. Each treatment was repeated three times. The statistical results of the experiments were analyzed by LSD test. Cr(III) addition in soil has shown that zeolite was the only amendment that increased the dry weight. Zeolite and bentonite reduced significantly the total chromium in plants after the addition of 50 mg L -1 Cr(III). The addition of Cr(VI) in soil has shown that bentonite was the only amendment that increased the dry weight of biomass and the plants' height. All soil amendments reduced to zero the total chromium concentration measured to plants after the addition of 1 mg L -1 Cr(VI).

Potential contribution of low cost materials in clean technology

NASA Astrophysics Data System (ADS)

Smail, Heman A.; Shareef, Kafia M.; Ramli, Zainab

2016-03-01

As the world's population approaches more than 9 billion, the strain on the planet's resources is steadily increasing. This demand can only be met by improving production methods to reduce the use of chemicals and the amount of chemical waste. Zeolites are among the least-known products for environmental pollution control, separation science and technology. This study investigates whether the use of geological sources as low-cost materials are suitable for zeolite synthesis and future applications. In this investigation natural montmorillonite clay, locally available in Erbil-Kurdistan, was used as raw material. The experiments were carried out in the presence of ultrasound 30KHz at 60°C and for different crystallization times (5, 10 &15 hours) and the results were compared with those obtained by performing conventional alkaline hydrothermal static syntheses under similar conditions and crystallization time of (90 hours). The raw material as well as the products was analyzed using; Fourier Transform Infra-Red (FT-IR), X-Ray Diffraction (XRD) and X-Ray Fluorescence (XRF) spectroscopy and scanning electron microscope (SEM). The experimental data were ascertained the formation of Zeolite successfully. Crystallization by ultrasound has been demonstrated to offer the possibilities of increasing the nucleation and crystallization rates of zeolites, improving the yield and directing the synthesis towards different crystal phases.

Study of Usage Areas of Clay Samples of Asphaltite Quarries in Sirnak, Turkey

NASA Astrophysics Data System (ADS)

Bilgin, Oyku

2017-12-01

The asphaltite of Sirnak, Turkey are in the form of 12 veins and their total reserves are anticipated to be approximately 200 million tons in a field of 25.000 hectares. The asphaltites at the Sirnak region are in the form of fault and crack fillings and take place together with clay minerals at their side rock. The main raw materials used in the production of cement are limestone, clay and marn known as sedimentary rocks. Limestone for CaO and clay minerals for SiO2, Al2O3, and Fe2O3, which are the main compounds of clinker production, are the main raw materials. Other materials containing these four oxides like marn are also used as cement raw material. Conformity levels of the raw materials to be used in cement production vary according to their chemical compounds. The rocks to be used as clay mineral are evaluated by taking the rate of silicate and alumina into consideration. The soils suitable for brick-tile productions are named as sandy clay. Their difference from the ceramic clays is that they are richer in terms of iron, silica and carbonate. These soils are also known under the names such as clay, arid, alluvium, silt, loam and argil. Inside these soils, minerals such as quartz, montmorillonite, kaolinite, calcite, limonite, hidromika, sericite, illite, and chlorite are available. Some parts of the soils consist of clays in amorphous structure. Limestone parts, gypsums, organic substances and bulky rock residuals spoil the quality. The soils suitable for brick production may not be suitable for tile production. In this case, their sandy soils should be mixed up with the clays with fine granule structure which is high in plasticity. During asphaltite mining in Sirnak region, clays forming side rock are gathered at dump sites. In this study; SQX analyses of the clay samples taken from Avgamasya, Seridahli and Segürük asphaltite veins run in Sirnak region are carried out and their usage areas are searched.

Physical Alteration of Martian Dust Grains, Its Influence on Detection of Clays and Identification of Aqueous Processes on Mars

NASA Technical Reports Server (NTRS)

Bishop, Janice L.; Drief, Ahmed; Dyar, Darby

2003-01-01

Clays, if present on Mars, have been illusive. Determining whether or not clay minerals and other aqueous alteration species are present on Mars provides key information about the extent and duration of aqueous processes on Mars. The purpose of this study is to characterize in detail changes in the mineral grains resulting from grinding and to assess the influence of physical processes on clay minerals on the surface of Mars. Physical alteration through grinding was shown to greatly affect the structure and a number of properties of antigorite and kaolinite. This project builds on an initial study and includes a combination of SEM, HRTEM, reflectance and M ssbauer spectroscopies. Grain size was found to decrease, as expected, with grinding. In addition, nanophase carbonate, Si-OH and iron oxide species were formed.

Effect of purity on adsorption capacities of a Mars-like clay mineral at different pressures

NASA Technical Reports Server (NTRS)

Jenkins, Traci; Mcdoniel, Bridgett; Bustin, Roberta; Allton, Judith H.

1992-01-01

There has been considerable interest in adsorption of carbon dioxide on Marslike clay minerals. Some estimates of the carbon dioxide reservoir capacity of the martian regolith were calculated from the amount of carbon dioxide adsorbed on the ironrich smectite nontronite under martian conditions. The adsorption capacity of pure nontronite could place upper limits on the regolith carbon dioxide reservoir, both at present martian atmospheric pressure and at the postulated higher pressures required to permit liquid water on the surface. Adsorption of carbon dioxide on a Clay Mineral Society standard containing nontronite was studied over a wide range of pressures in the absence of water. Similar experiments were conducted on the pure nontronite extracted from the natural sample. Heating curves were obtained to help characterize and determine the purity of the clay sample.

Distribution of clay minerals in surface sediments of the western Gulf of Thailand: Sources and transport patterns

NASA Astrophysics Data System (ADS)

Shi, Xuefa; Liu, Shengfa; Fang, Xisheng; Qiao, Shuqing; Khokiattiwong, Somkiat; Kornkanitnan, Narumol

2015-06-01

A high density sampling program during two joint China-Thailand scientific cruises in 2011-2012 included collection of 152 gravity box cores in the Gulf of Thailand (GoT). Samples from the top 5 cm of each core were analyzed by X-ray diffraction for clay mineral content. Several systemic analytical approaches were applied to examine the distribution pattern and the constraint factors of clay minerals in the surface sediments of the western GoT. The clay minerals mainly comprise illite, kaolinite, chlorite and smectite, having the average weight percent distributions of 50%, 34%, 14% and 2%, respectively. Based on the spatial distribution characteristics and statistical results, the study area can be classified into three provinces. Province I contains high concentrations of smectite, and covers the northern GoT, sediments in this province are mainly from rivers discharging into the upper GoT, especially the Chao Phraya and Mae Klong Rivers. Sediments in Province II are characterized by higher values of illite, located in the central GoT, where fine sediments are contributed by the Mekong River and from the South China Sea. Province Ш, in the coastal regions of southwestern GoT close to Malaysia, exhibits a clay mineral assemblage with complex distribution patterns, and may contain terrestrial materials from the Mae Klong River as well as re-suspended sediments. Results of integrative analysis also demonstrate that the hydrodynamic environment in the study area, especially the seasonal various circumfluence and eddies, play an important role in the spatial distribution and dispersal of clay fraction in sediments.

Growth of Iron(III)-Reducing Bacteria on Clay Minerals as the Sole Electron Acceptor and Comparison of Growth Yields on a Variety of Oxidized Iron Forms†

PubMed Central

Kostka, Joel E.; Dalton, Dava D.; Skelton, Hayley; Dollhopf, Sherry; Stucki, Joseph W.

2002-01-01

Smectite clay minerals are abundant in soils and sediments worldwide and are typically rich in Fe. While recent investigations have shown that the structural Fe(III) bound in clay minerals is reduced by microorganisms, previous studies have not tested growth with clay minerals as the sole electron acceptor. Here we have demonstrated that a pure culture of Shewanella oneidensis strain MR-1 as well as enrichment cultures of Fe(III)-reducing bacteria from rice paddy soil and subsurface sediments are capable of conserving energy for growth with the structural Fe(III) bound in smectite clay as the sole electron acceptor. Pure cultures of S. oneidensis were used for more detailed growth rate and yield experiments on various solid- and soluble-phase electron acceptors [smectite, Fe(III) oxyhydroxide FeOOH, Fe(III) citrate, and oxygen] in the same minimal medium. Growth was assessed as direct cell counts or as an increase in cell carbon (measured as particulate organic carbon). Cell counts showed that similar growth of S. oneidensis (108 cells ml−1) occurred with smectitic Fe(III) and on other Fe forms [amorphous Fe(III) oxyhydroxide, and Fe citrate] or oxygen as the electron acceptor. In contrast, cell yields of S. oneidensis measured as the increase in cell carbon were similar on all Fe forms tested while yields on oxygen were five times higher, in agreement with thermodynamic predictions. Over a range of particle loadings (0.5 to 4 g liter−1), the increase in cell number was highly correlated to the amount of structural Fe in smectite reduced. From phylogenetic analysis of the complete 16S rRNA gene sequences, a predominance of clones retrieved from the clay mineral-reducing enrichment cultures were most closely related to the low-G+C gram-positive members of the Bacteria (Clostridium and Desulfitobacterium) and the δ-Proteobacteria (members of the Geobacteraceae). Results indicate that growth with smectitic Fe(III) is similar in magnitude to that with Fe(III) oxide minerals and is dependent upon the mineral surface area available. Iron(III) bound in clay minerals should be considered an important electron acceptor supporting the growth of bacteria in soils or sedimentary environments. PMID:12450850

Sand and clay mineralogy of sal forest soils of the Doon Siwalik Himalayas

NASA Astrophysics Data System (ADS)

Mukesh; Manhas, R. K.; Tripathi, A. K.; Raina, A. K.; Gupta, M. K.; Kamboj, S. K.

2011-02-01

The peteromineralogical characterization of the soil was carried out for the 12 soil profiles exposed in the Shorea robusta dominated forests of the Siwalik forest division, Dehradun. The quartz was observed as the dominating light mineral fraction (64-80%) in all the profiles studied. Biotite, hornblende, zircon, tourmaline, rutile and opaques comprising of iron minerals constituted the heavy mineral fraction (20%). The mineralogy of both the sand and clay fractions revealed a mixed mineralogy. The clay minerals in the order of their dominance were vermiculite, illite, kaolinite and mixed layer minerals. The presence of vermiculite and illite in appreciable quantities indicates that these were synthesized from the K-rich soil solution, as orthoclase and micas were present in significant quantities in the sand minerals. The mineral suites identified in the study shows that the geological, climatological and topographical factors of the region collectively played a dominant role in their formation and transformation. After critical appraisal of the results, it may be deduced that the mineralogical composition, physicochemical properties and total elemental analysis of the soils do not show any deficiency of the bases and other plant nutrients in general. The inherent fertility of the soil is good as indicated by the sand and clay mineralogy of the soil and the biotite and feldspar together with the mica is an important source of nutrients for the vegetation in the soils of the Doon valley.

Influences of Sedimentary Environments and Volcanic Sources on Diagenetic Alteration of Volcanic Tuffs in South China.

PubMed

Gong, Nina; Hong, Hanlie; Huff, Warren D; Fang, Qian; Bae, Christopher J; Wang, Chaowen; Yin, Ke; Chen, Shuling

2018-05-16

Permian-Triassic (P-Tr) altered volcanic ashes (tuffs) are widely distributed within the P-Tr boundary successions in South China. Volcanic altered ashes from terrestrial section-Chahe (CH) and marine section-Shangsi (SS) are selected to further understand the influence of sedimentary environments and volcanic sources on diagenetic alterarion on volcanic tuffs. The zircon 206 Pb/ 238 U ages of the corresponding beds between two sections are almost synchronous. Sedimentary environment of the altered tuffs was characterized by a low pH and did not experience a hydrothermal process. The dominant clay minerals of all the tuff beds are illite-smectite (I-S) minerals, with minor chlorite and kaolinite. I-S minerals of CH (R3) are more ordered than SS (R1), suggesting that CH also shows a higher diagenetic grade and more intensive chemical weathering. Besides, the nature of the volcanism of the tuff beds studied is derived from different magma sources. The clay mineral compositions of tuffs have little relation with the types of source volcanism and the depositional environments. Instead, the degree of the mixed-layer clay minerals and the REE distribution are mainly dependent upon the sedimentary environments. Thus, the mixed-layer clay minerals ratio and their geochemical index can be used as the paleoenvironmental indicator.

Green Clay Minerals

NASA Astrophysics Data System (ADS)

Velde, B.

2003-12-01

Color is a problem for scientific study. One aspect is the vocabulary one used to describe color. Mint green, bottle green, and Kelly green are nice names but not of great utility in that people's physical perception of color is not always the same. In some industries, such as colored fabric manufacture, current use is to send a set of standard colors which are matched by the producer. This is similar to the use of the Munsell color charts in geology. None of these processes makes use of physical optical spectral studies. The reason is that they are difficult to obtain and interpret. For a geologist, color is very important but we rarely have the possibility to standardize the method of our color perception. One reason is that color is both a reflective and transmission phenomenon. The thickness of the sample is critical to any transmission characteristics. Hence, a field color determination is different from one made by using a petrographic microscope. Green glauconite in a hand specimen is not the same color in 30 μm thick thin section seen with a microscope using transmitted light.A second problem is that color in a spectral identification is the result of several absorption emissions,with overlapping signal, forming a complicated spectrum. Interpretation depends very greatly on the spectrum of the light source and the conditions of transmission-reflection of the sample. As a result, for this text, we will not attempt to analyze the physical aspect of green in green clays. In the discussion which follows, reference is made concerning color, to thin section microscopic perception.Very briefly, green clay minerals are green, because they contain iron. This is perhaps not a great revelation to mineralogists, but it is the key to understanding the origin and stability of green clay minerals. In fact, iron can color minerals either red or green or in various shades of orange and brown. The color most likely depends upon the relative abundance of the iron ion valence in the silicate (clay mineral in our case) structure, the specific bonding of these ions, and other factors. In fact, the reasons for coloration are not known completely, but it is certain that a combination of Fe2+ and Fe3+ ions is necessary to give a nice green color to clays. In the green clay minerals discussed here, the colors vary greatly as seen under the optical microscope (not always the same as the one seen in hand specimen). Yellow to blue-green hues can be found. However, for the moment, no clear relation between iron content, iron valence ratio, or other factors such as minor transition element concentrations can be found to explain the greenness of green clay minerals. The fact that a clay is green just indicates a combination of the two oxidation states of iron. The color, however, indicates the key to the formation in nature of green clay minerals.Green clay minerals are in general the product of "mixed valence" conditions of formation, most often in a situation where some iron is reduced from Fe3+ and enters into a silicate mineral structure. In general, iron would rather be an oxide when it is in the trivalent state. The moment iron is reduced to a divalent state under surface or near-surface conditions, it looks for a silicate, sulfide, or carbonate to hide in. The reverse is also true, of course. When a silicate is oxidized, Fe2+ becoming Fe3+, the iron begins to group together in oxide clumps and eventually exits the silicate structure. This is seen in thin section in altered rocks (weathering or hydrothermal action). The production of trivalent, oxidized iron usually results in a brownish or orange mineral.If the geology of the formation of green silicate minerals is relatively well defined, especially at near surface or surface conditions, the question remains how much of the iron is in a reduced oxidation state and how? In the case of reduction of iron in surface environments: if most of the iron goes to Fe2+, one mineral is formed; if only part of it is reduced, another is formed. This is the fundamental geochemical aspect of the genesis of green clay minerals; they contain iron in both oxidation states.Unfortunately modern methods of mineral analysis on a microscopic scale, electron microbeam and others, do not allow the determination of the different oxidation states of iron especially for nonstoichiometric minerals. One can use Mössbauer spectral analysis, but the scales of observations are not the same (Mössbauer needing more material); one method used for observations on a microscale, the other on a macroscale. Given the problems of micro- and macroscale observations, oxidation state information is almost excluded from data gathered since the 1980s or so, and hence information concerning the relations of iron reduction and clay genesis must be taken from older studies. A second, much greater problem is that little X-ray diffraction (XRD) work is done on samples which are analyzed chemically by electron microbeam studies. In the past both types of information, structural and chemical, were available for the same sample. Hence not only do we have no precise chemical data for many samples (oxidation state of iron), but there is a rarity of mineral structural information to go along with the incomplete chemistry. This is critical for the study of clay minerals, because slight chemical changes in a clay mineral are frequently accompanied by changes in its structure, especially when one deals with interstratified clay minerals (mica/smectites for example). In fact, the tendency to obtain more and more precision (analysis of a smaller and smaller sized sample) has led to a total loss of mineralogical data. The Heisenberg principle is unwittingly verified by geologists. We know more about a small part of a sample, but we know less about its whole. As a result, the following discussion is based largely upon old data, those which combine iron oxidation states and XRD information.

Distribution and possible immobilization of lead in a forest soil (Luvisol) profile.

PubMed

Sipos, Péter; Németh, Tibor; Mohai, Ilona

2005-02-01

Geochemical analyses using a sequential extraction method and lead adsorption studies were carried out in order to characterize the distribution and adsorption of lead on each genetic horizon of a Luvisol profile developed on a pelagic clayey aleurolite. Clay illuviation is the most important pedogenic process in the profile studied. Its clay mineralogy is characterized by chlorite/vermiculite species with increasing chlorite component downward. The amount of carbonate minerals strongly increases in the lower part of the profile resulting in an abrupt rise in soil pH within a small distance. The Pb content of the soil profile exceeds the natural geochemical background only in the Ao horizon, and its amount decreases with depth in the profile without correcting for differences in bulk density, suggesting the binding of Pb to soil organic matter. According to the sequential extraction analysis the organic matter and carbonate content of the soil have the most significant effect on lead distribution. This effect varies in the different soil horizons. Lead adsorption experiments were carried out on whole soil samples, soil clay fractions, as well as on their carbonate and organic matter free variant. The different soil horizons adsorb lead to different extents depending on their organic matter, clay mineral and carbonate content; and the mineralogical features of soil clays significantly affect their lead adsorption capacity. The clay fraction adsorbs 25% more lead than the whole soil, while in the calcareous subsoil a significant proportion of lead is precipitated due to the alkaline conditions. 10 and 5% of adsorbed Pb can be leached with distilled water in the organic matter and clay mineral dominated soil horizons, respectively. These results suggest that soil organic matter plays a decisive role in the adsorption of Pb, but the fixation by clay minerals is stronger.

Effect of Mineral and Microbe Interactions on Biomass Yield

NASA Astrophysics Data System (ADS)

Pena, S. A.; Block, K. A.; Katz, A.; Gottlieb, P.

2016-12-01

The ecological feedback of microbes (bacteria and viruses) in association with minerals is virtually unexplored in the context of characterizing how carbon cycles in the terrestrial ecosystem. These interactions include the ability for bacteriophage to control bacteria populations, the ability of minerals to provide a substrate for bacteria growth, and the effect of minerals on bacteriophage viability. We investigate bacteriophage aggregation with minerals in the clay size fraction (< 0.2 µm) as well as the interaction between bacteriophage and mineral biofilms. In our virus experiments, bacteriophage Φ6 was suspended with the minerals smectite, illite, kaolinite, and goethite at low divalent cation concentrations so aggregation was in the reaction limited colloidal aggregation (RLCA) regime, at neutral pH and room temperature conditions. Virus remained viable at a 1:1 virus-clay ratio for clays, and at an approximate 100:1 ratio for goethite. However, the number of plaque forming units was reduced by 99%. Electron micrographs show viable as well as partially disassembled virus, similar to the results found by Block et al. 2014. We found that inactivation of a 4 x 1011 cm-3 concentration of bacteriophage Φ6 by smectite, illite, kaolinite, and goethite, required a minimum sediment concentration of 1.5 x 1011 cm-3, 1.4 x 1011 cm-3, 2.5 x 1011 cm-3, and 1.1 x 109 cm-3, respectively. Mineral biofilms were generated by suspension of tropical soil clays with gram-positive and gram-negative microbes and characterized by x-ray diffraction and imaged by electron microscopy (SEM and TEM). Mineral biomass produced by gram negative organisms were subjected to virus infection to determine influence of minerals on community resilience. Lastly, we report biomass yield in each instance to quantify the influence of mineral composition on total biomass production.

Modeling selenate adsorption behavior on oxides, clay minerals, and soils using the triple layer model

USDA-ARS?s Scientific Manuscript database

Selenate adsorption behavior was investigated on amorphous aluminum oxide, amorphous iron oxide, goethite, clay minerals: kaolinites, montmorillonites, illite, and 18 soil samples from Hawaii, and the Southwestern and the Midwestern regions of the US as a function of solution pH. Selenate adsorpti...

Modeling selenite adsorption envelopes on oxides, clay minerals, and soils using the triple layer model

USDA-ARS?s Scientific Manuscript database

Selenite adsorption behavior was investigated on amorphous aluminum and iron oxides, clay minerals: kaolinite, montmorillonite, and illite, and 45 surface and subsurface soil samples from the Southwestern and Midwestern regions of the USA as a function of solution pH. Selenite adsorption decreased ...

Picloram and Aminopyralid Sorption to Soil and Clay Minerals

USDA-ARS?s Scientific Manuscript database

Aminopyralid sorption data are lacking, and these data are needed to predict off-target transport and plant available herbicide in soil solution. The objective of this research was to determine the sorption of picloram and aminopyralid to five soils and three clay minerals and determine if the pote...

A recommended procedure for the preparation of oriented clay-mineral specimens for X-ray diffraction analysis; modifications to Drever's filter-membrane peel technique

USGS Publications Warehouse

Pollastro, R.M.

1982-01-01

Extremely well-oriented clay mineral mounts for X-ray diffraction analysis can be prepared quickly and without introducing segregation using the filter-membrane peel technique. Mounting problems encountered with smectite-rich samples can be resolved by using minimal sample and partial air-drying of the clay film before transfer to a glass slide. Samples containing small quantities of clay can produce useful oriented specimens if Teflon masks having more restrictive areas are inserted above the membrane filter during clay deposition. War]page and thermal shock of glass slides can be controlled by using a flat, porous, ceramic plate as a holding surface during heat treatments.

Slow release of NO by microporous titanosilicate ETS-4.

PubMed

Pinto, Moisés L; Rocha, João; Gomes, José R B; Pires, João

2011-04-27

A novel approach to designing nitric oxide (NO) storage and releasing microporous agents based on very stable, zeolite-type silicates possessing framework unsaturated transition-metal centers has been proposed. This idea has been illustrated with ETS-4 [Na(9)Si(12)Ti(5)O(38)(OH)·xH(2)O], a titanosilicate that displays excellent NO adsorption capacity and a slow releasing kinetics. The performance of these materials has been compared to the performance of titanosilicate ETS-10, [(Na,K)(2)Si(5)TiO(13)·xH(2)O], of benchmark zeolites mordenite and CaA, and of natural and pillared clays. DFT periodic calculations have shown that the presence of water in the pores of ETS-4 promotes the NO adsorption at the unsaturated (pentacoordinated) Ti(4+) framework ions.

Adsorption coefficients for TNT on soil and clay minerals

NASA Astrophysics Data System (ADS)

Rivera, Rosángela; Pabón, Julissa; Pérez, Omarie; Muñoz, Miguel A.; Mina, Nairmen

2007-04-01

To understand the fate and transport mechanisms of TNT from buried landmines is it essential to determine the adsorption process of TNT on soil and clay minerals. In this research, soil samples from horizons Ap and A from Jobos Series at Isabela, Puerto Rico were studied. The clay fractions were separated from the other soil components by centrifugation. Using the hydrometer method the particle size distribution for the soil horizons was obtained. Physical and chemical characterization studies such as cation exchange capacity (CEC), surface area, percent of organic matter and pH were performed for the soil and clay samples. A complete mineralogical characterization of clay fractions using X-ray diffraction analysis reveals the presence of kaolinite, goethite, hematite, gibbsite and quartz. In order to obtain adsorption coefficients (K d values) for the TNT-soil and TNT-clay interactions high performance liquid chromatography (HPLC) was used. The adsorption process for TNT-soil was described by the Langmuir model. A higher adsorption was observed in the Ap horizon. The Freundlich model described the adsorption process for TNT-clay interactions. The affinity and relative adsorption capacity of the clay for TNT were higher in the A horizon. These results suggest that adsorption by soil organic matter predominates over adsorption on clay minerals when significant soil organic matter content is present. It was found that, properties like cation exchange capacity and surface area are important factors in the adsorption of clayey soils.

Experimental Insights into Multiphase (H2O-CO2) Fluid-Rock Interactions in Geothermal Systems

NASA Astrophysics Data System (ADS)

Kaszuba, J. P.; Lo Re, C.; Martin, J.; McPherson, B. J.; Moore, J. N.

2012-12-01

Integrated hydrothermal experiments and geochemical modeling elucidate fluid-rock interactions and reaction pathways in both natural and anthropogenic systems, including enhanced geothermal systems (EGS) in which CO2 is introduced as a working fluid. Experiments are conducted in rocker bombs and flexible Au-Ti reaction cells. Individual experiments require one to three months to complete; intensive in-situ fluid/gas sampling gauges reaction progress. Investigation of granitic reservoirs and associated vein minerals are broadly based on the Roosevelt Hot Springs thermal area, Utah, USA. The granite consists of subequal amounts of quartz, perthitic K-feldspar (~25% wt% albite and 75% wt% K-feldspar), and oligoclase (An23), and 4 wt% Fe-rich biotite. Vein minerals include epidote and chlorite (clinochlore). Experiments are conducted at 250°C and 25 to 45 MPa. Each experiment uses mineral powders (75 wt% of rock mass, ground to <45 um) to increase reactivity and also mineral pieces (0.1-0.7 cm in size) to promote petrologic evaluation of mineral reactions. The water (I ≈ 0.1 molal) initially contains millimolal quantities of SiO2, Al, Ca, Mg, K, SO4, and HCO3 and is designed to be saturated with all of the minerals present at the start of each experiment. Excess CO2 is injected to saturate the water and maintain an immiscible supercritical fluid phase. The entire evolutionary path of the natural system is not replicated at laboratory scales. Instead, experiments define a segment of the reaction path and, in combination with geochemical modeling, provide clear trajectories towards equilibrium. Reaction of granite+water yields illite+zeolite; smectite subsequently precipitates in response to CO2 injection. Reaction of granite+epidote+water yields illite+zeolite+smectite; zeolite does not precipitate after CO2 is injected. Water in all experiments become saturated with chalcedony. Carbonate minerals do not precipitate but are predicted as final equilbrium products. Enhanced Geothermal Systems are expected to follow similar reaction pathways and produce metastable minerals during initial development.

Surfactant-Modified Soil Amendments Reduce Nitrogen and Phosphorus Leaching in a Sand-Based Rootzone.

PubMed

Shaddox, Travis W; Kruse, Jason K; Miller, Grady L; Nkedi-Kizza, Peter; Sartain, Jerry B

2016-09-01

United States Golf Association putting greens are susceptible to nitrogen (N) and phosphorus (P) leaching. Inorganic soil amendments are used to increase moisture and nutrient retention and may influence N and P leaching. This study was conducted to determine whether N and P leaching could be reduced using soil amendments and surfactant-modified soil amendments. Treatments included a control (sand), sand-peat, zeolite, calcined clay, hexadecyltrimethylammonium-zeolite, and hexadecyltrimethylammonium-calcined clay. Lysimeters were filled with a 30-cm rootzone layer of sand-peat (85:15 by volume), below which a 5-cm treatment layer of amendments was placed. A solution of NO-N, NH-N, and orthophosphate-P (2300, 2480, and 4400 μg mL, respectively) was injected at the top of each lysimeter, and leachate was collected using an autocollector set to collect a 10-mL sample every min until four pore volumes were collected. Uncoated amendments, sand, and peat had no influence on NO-N retention, whereas hexadecyltrimethylammonium-coated amendments reduced NO-N leaching to below detectable limits. Both coated and uncoated amendments reduced NH-N leaching, with zeolite reducing NH-N leached to near zero regardless of hexadecyltrimethylammonium coating. Pure sand resulted in a 13% reduction of applied orthophosphate-P leaching, whereas peat contributed to orthophosphate-P leaching. Surfactant-modified amendments reduced orthophosphate-P leaching by as much as 97%. Surfactant-modified soil amendments can reduce NO-N, NH-N, and orthophosphate-P leaching and, thus, may be a viable option for removing leached N and P before they enter surface or ground waters. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Early containment of high-alkaline solution simulating low-level radioactive waste stream in clay-bearing blended cement

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kruger, A.A.; Olson, R.A.; Tennis, P.D.

1995-04-01

Portland cement blended with fly ash and attapulgite clay was mixed with high-alkaline solution simulating low-level radioactive waste stream at a one-to-one weight ratio. Mixtures were adiabatically and isothermally cured at various temperatures and analyzed for phase composition, total alkalinity, pore solution chemistry, and transport properties as measured by impedance spectroscopy. Total alkalinity is characterized by two main drops. The early one corresponds to a rapid removal of phosphorous, aluminum, sodium, and to a lesser extent potassium solution. The second drop from about 10 h to 3 days is mainly associated with the removal of aluminum, silicon, and sodium. Thereafter,more » the total alkalinity continues descending, but at a lower rate. All pastes display a rapid flow loss that is attributed to an early precipitation of hydrated products. Hemicarbonate appears as early as one hour after mixing and is probably followed by apatite precipitation. However, the former is unstable and decomposes at a rate that is inversely related to the curing temperature. At high temperatures, zeolite appears at about 10 h after mixing. At 30 days, the stabilized crystalline composition Includes zeolite, apatite and other minor amounts of CaCO{sub 3}, quartz, and monosulfate Impedance spectra conform with the chemical and mineralogical data. The normalized conductivity of the pastes shows an early drop, which is followed by a main decrease from about 12 h to three days. At three days, the permeability of the cement-based waste as calculated by Katz-Thompson equation is over three orders of magnitude lower than that of ordinary portland cement paste. However, a further decrease in the calculated permeability is questionable. Chemical stabilization is favorable through incorporation of waste species into apatite and zeolite.« less

Nanoscale zero valent supported by Zeolite and Montmorillonite: Template effect of the removal of lead ion from an aqueous solution.

PubMed

Arancibia-Miranda, Nicolás; Baltazar, Samuel E; García, Alejandra; Muñoz-Lira, Daniela; Sepúlveda, Pamela; Rubio, María A; Altbir, Dora

2016-01-15

In this work, we have studied the Pb(2+) sorption capacity of Zeolite (Z) and Montmorillonite (Mt) functionalized with nanoscale zero-valent iron (nZVI), at 50% w/w, obtained by means of an impregnating process with a solvent excess. The composites were characterized by several techniques including X-ray diffraction; scanning electron microscopy (SEM); BET area; isoelectric point (IEP); and, finally a magnetic response. Comparatively significant differences in terms of electrophoretic and magnetic characteristics were found between the pristine materials and the composites. Both structures show a high efficiency and velocity in the removal of Pb(2+) up to 99.0% (200.0 ppm) after 40 min of reaction time. The removal kinetics of Pb(2+) is adequately described by the pseudo second-order kinetic model, and the maximum adsorbed amounts (q(e)) of this analyte are in close accordance with the experimental results. The intraparticle diffusion model shows that this is not the only rate-limiting step, this being the Langmuir model which was well adjusted to our experimental data. Therefore, maximum sorption capacities were found to be 115.1±11.0, 105.5±9.0, 68.3±1.3, 54.2±1.3, and 50.3±4.2 mg g(-1), for Mt-nZVI, Z-nZVI, Zeolite, Mt, and nZVI, respectively. The higher sorption capacities can be attributed to the synergetic behavior between the clay and iron nanoparticles, as a consequence of the clay coating process with nZVI. These results suggest that both composites could be used as an efficient adsorbent for the removal of lead from contaminated water sources. Copyright © 2015 Elsevier B.V. All rights reserved.

Permeability of Granite Including Macro-Fracture Naturally Filled with Fine-Grained Minerals

NASA Astrophysics Data System (ADS)

Nara, Yoshitaka; Kato, Masaji; Niri, Ryuhei; Kohno, Masanori; Sato, Toshinori; Fukuda, Daisuke; Sato, Tsutomu; Takahashi, Manabu

2018-03-01

Information on the permeability of rock is essential for various geoengineering projects, such as geological disposal of radioactive wastes, hydrocarbon extraction, and natural hazard risk mitigation. It is especially important to investigate how fractures and pores influence the physical and transport properties of rock. Infiltration of groundwater through the damage zone fills fractures in granite with fine-grained minerals. However, the permeability of rock possessing a fracture naturally filled with fine-grained mineral grains has yet to be investigated. In this study, the permeabilities of granite samples, including a macro-fracture filled with clay and a mineral vein, are investigated. The permeability of granite with a fine-grained mineral vein agrees well with that of the intact sample, whereas the permeability of granite possessing a macro-fracture filled with clay is lower than that of the macro-fractured sample. The decrease in the permeability is due to the filling of fine-grained minerals and clay in the macro-fracture. It is concluded that the permeability of granite increases due to the existence of the fractures, but decreases upon filling them with fine-grained minerals.

Pedogenic formation of montmorillonite from a 2:1-2:2 intergrade clay mineral

USGS Publications Warehouse

Malcolm, R.L.; Nettleton, W.D.; McCracken, R.J.

1968-01-01

Montmorillonite was found to be the dominant clay mineral in surface horizons of certain soils of the North Carolina Coastal Plain whereas a 2:1-2:2 intergrade clay mineral was dominant in subjacent horizons. In all soils where this clay mineral sequence was found, the surface horizon was low in pH (below 4⋅5) and high in organic matter content. In contrast, data from studies of other soils of this region (Weed and Nelson, 1962) show that: (1) montmorillonite occurs infrequently; (2) maximum accumulation of the 2:1-2:2 intergrade normally occurs in the surface horizon and decreases with depth in the profile; (3) organic matter contents are low; and (4) pH values are only moderately acid (pH 5-6).It is theorized that the montmorillonite in the surface horizon of the soils studied originated by pedogenic weathering of the 2:1-2:2 intergrade clay mineral. The combined effects of low pH (below 4⋅5) and high organic matter content in surface horizons are believed to be the agents responsible for this mineral transformation. The protonation and solubilization (reverse of hydrolysis) of Al-polymers in the interlayer of expansible clay minerals will occur at or below pH 4⋅5 depending on the charge and steric effects of the interlayer. A low pH alone may cause this solubilization and thus mineral transformation, but in the soils studied the organic matter is believed to facilitate and accelerage the transformation. The intermediates of organic matter decomposition provide an acid environment, a source of protons, and a source of watersoluble mobile organic substances (principally fulvic acids) which have the ability to complex the solubilized aluminum and move it down the profile. This continuous removal of solubilized aluminum would provide for a favorable gradient for aluminum solubilization.The drainage class or position in a catena is believed to be less important than the chemical factors in formation of montmorillonite from 2:1-2:2 intergrade, because montmorillonite is present in all drainage classes if the surface horizon is low in pH and high in organic matter.

Reactive transport modeling of CO2 mineral sequestration in basaltic rocks

NASA Astrophysics Data System (ADS)

Aradottir, E. S.; Sonnenthal, E. L.; Bjornsson, G.; Jonsson, H.

2011-12-01

CO2 mineral sequestration in basalt may provide a long lasting, thermodynamically stable, and environmentally benign solution to reduce greenhouse gases in the atmosphere. Multi-dimensional, field scale, reactive transport models of this process have been developed with a focus on the CarbFix pilot CO2 injection in Iceland. An extensive natural analog literature review was conducted in order to identify the primary and secondary minerals associated with water-basalt interaction at low and elevated CO2 conditions. Based on these findings, an internally consistent thermodynamic database describing the mineral reactions of interest was developed and validated. Hydrological properties of field scale mass transport models were properly defined by calibration to field data using iTOUGH2. Reactive chemistry was coupled to the models and TOUGHREACT used for running predictive simulations carried out with the objective of optimizing long-term management of injection sites, to quantify the amount of CO2 that can be mineralized, and to identify secondary minerals that compete with carbonates for cations leached from the primary rock. Calibration of field data from the CarbFix reservoir resulted in a horizontal permeability for lava flows of 300 mD and a vertical permeability of 1700 mD. Active matrix porosity was estimated to be 8.5%. The CarbFix numerical models were a valuable engineering tool for designing optimal injection and production schemes aimed at increasing groundwater flow. Reactive transport simulations confirm dissolution of primary basaltic minerals as well as carbonate formation, and thus indicate in situ CO2 mineral sequestration in basalts to be a viable option. Furthermore, the simulations imply that clay minerals are most likely to compete with magnesite-siderite solid solutions for Mg and Fe leached from primary minerals, whereas zeolites compete with calcite for dissolved Ca. In the case of the CarbFix pilot injection, which involves a continuous injection of 1,100 tons CO2 in total for 6 months, the basalt hosted reservoir was estimated to have a 100% sequestering efficiency after 10 years. In the case of an upscaled 10 year long injection of 40,000 tons per year, sequestering efficiency of the same reservoir was estimated to be about 10% after 100 years. However, sequestering efficiency in the latter case has every potential of increasing substantially with time due to the vast amount of primary basaltic minerals in the reservoir.

Ball clay

USGS Publications Warehouse

Virta, R.L.

2001-01-01

Part of the 2000 annual review of the industrial minerals sector. A general overview of the ball clay industry is provided. In 2000, sales of ball clay reached record levels, with sanitary ware and tile applications accounting for the largest sales. Ball clay production, consumption, prices, foreign trade, and industry news are summarized. The outlook for the ball clay industry is also outlined.

Adsorption of Aqueous Crude Oil Components on the Basal Surfaces of Clay Minerals: Molecular Simulations Including Salinity and Temperature Effects

DOE PAGES

Greathouse, J. A.; Cygan, R. T.; Fredrich, J. T.; ...

2017-09-28

Molecular simulations of the adsorption of representative organic molecules onto the basal surfaces of various clay minerals were used to assess the mechanisms of enhanced oil recovery associated with salinity changes and water flooding. Simulations at the density functional theory (DFT) and classical levels provide insights into the molecular structure, binding energy, and interfacial behavior of saturate, aromatic, and resin molecules near clay mineral surfaces. Periodic DFT calculations reveal binding geometries and ion pairing mechanisms at mineral surfaces while also providing a basis for validating the classical force field approach. Through classical molecular dynamics simulations, the influence of aqueous cationsmore » at the interface and the role of water solvation are examined to better evaluate the dynamical nature of cation-organic complexes and their co-adsorption onto the clay surfaces. The extent of adsorption is controlled by the hydrophilic nature and layer charge of the clay mineral. All organic species studied showed preferential adsorption on hydrophobic mineral surfaces. However, the anionic form of the resin (decahydro-2-naphthoic acid)—expected to be prevalent at near-neutral pH conditions in petroleum reservoirs—readily adsorbs to the hydrophilic kaolinite surface through a combination of cation pairing and hydrogen bonding with surface hydroxyl groups. Analysis of cation-organic pairing in both the adsorbed and desorbed states reveals a strong preference for organic anions to coordinate with divalent calcium ions rather than monovalent sodium ions, lending support to current theories regarding low-salinity water flooding.« less

Adsorption of Aqueous Crude Oil Components on the Basal Surfaces of Clay Minerals: Molecular Simulations Including Salinity and Temperature Effects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Greathouse, J. A.; Cygan, R. T.; Fredrich, J. T.

Molecular simulations of the adsorption of representative organic molecules onto the basal surfaces of various clay minerals were used to assess the mechanisms of enhanced oil recovery associated with salinity changes and water flooding. Simulations at the density functional theory (DFT) and classical levels provide insights into the molecular structure, binding energy, and interfacial behavior of saturate, aromatic, and resin molecules near clay mineral surfaces. Periodic DFT calculations reveal binding geometries and ion pairing mechanisms at mineral surfaces while also providing a basis for validating the classical force field approach. Through classical molecular dynamics simulations, the influence of aqueous cationsmore » at the interface and the role of water solvation are examined to better evaluate the dynamical nature of cation-organic complexes and their co-adsorption onto the clay surfaces. The extent of adsorption is controlled by the hydrophilic nature and layer charge of the clay mineral. All organic species studied showed preferential adsorption on hydrophobic mineral surfaces. However, the anionic form of the resin (decahydro-2-naphthoic acid)—expected to be prevalent at near-neutral pH conditions in petroleum reservoirs—readily adsorbs to the hydrophilic kaolinite surface through a combination of cation pairing and hydrogen bonding with surface hydroxyl groups. Analysis of cation-organic pairing in both the adsorbed and desorbed states reveals a strong preference for organic anions to coordinate with divalent calcium ions rather than monovalent sodium ions, lending support to current theories regarding low-salinity water flooding.« less

Composition and properties of the Pierre Shale and equivalent rocks, northern Great Plains region

USGS Publications Warehouse

Schultz, Leonard Gene; Tourtelot, H.A.; Gill, J.R.; Boerngen, J.G.

1980-01-01

The Pierre Shale and equivalent rocks of Late Cretaceous age consist in the east-central Dakotas of several hundred feet of offshore-marine shale and minor marl; in west-central Montana near the sediment source the equivalents of the Pierre Shale consist of several thousand feet of volcanic-rich and mostly nonmarine sediments; and in the area between, both types of rock are separated by tongues of nearshore-marine siltstone and sandstone that mark three major transgressions of the sea across the area. The major-, minor-, and trace-element composition was determined for 226 samples of these rocks, and the mineralogical composition was determined for 1,350 samples. Slurry pH, Atterberg limits, and grain and bulk densities were determined on some samples. The arithmetic mean, in percent, and standard deviation (in parentheses) of major and minor elements, mostly in shale and siltstone and excluding the 23 chemically analyzed bentonite samples, are as follows: SiO2 60.8 (7.9) Al2O3 14.4 (2.5) Fe2O3 3.4 (1.4) FeO 1.1 (1.2) MgO 2.2 (1.0) CaO 2.7 (0.48) Na2O 1.1 (0.56) K2O 2.4 (0.57) H2O- 3.2 (1.3) H2O+ 4.3 (1.2) TiO2 0.58 (0.12) P2O5 0.14 (0.073) S 0.37 (1.1) F 0.71 (0.15) Cl 0.16 (0.024) CO2 2.1 (7.0) C, organic 0.94 (1.8) The mean and standard deviation of minerals as determined by X-ray methods, excluding bentonite samples, is as follows: clay minerals, 53 (20); quartz, 24 (13); cristobalite, 1 (5); potassium-feldspar, 1 (2); plagioclase, 6 (7); anorthite content from 20 to 40 percent; calcite, 5 (14); dolomite, 4 (7); organic matter, 1 (2); and sparsely scattered gypsum, jarosite, pyrite, zeolites, augite, siderite, and probably minor amounts of hydrated iron-manganese (Fe-Mn) oxides. The mean and standard deviation of the clay-mineral fraction is as follows: mixed-layer illite-smectite, 70 (20); illite, 16 (9); chlorite, 3 (6); and kaolinite, 9 (13). The mixed-layer clay, except in the Montana disturbed belt, is a random interlayering of 20 to 60 percent illite-type layers, about 35 percent beidelite-type layers, and the remainder montmorillonite-type layers; chlorite or vermiculite layers are rare. Most bentonite differs from shale in its small quartz content, rarely more than a few percent, in the more calcic composition and hightemperature thermal state of its plagioclase, and in its rare kaolinite, near absence of chlorite, and lack of illite-either free or mixed layered with smectite. Bentonite commonly consists of more than 90 percent smectite in which montmorillonite is interlayered with a smaller amount of beidellite. The clay-mineral composition of marine rock, including proportions of layers in the dominant illite-smectite, averages about the same as in the nonmarine rock, though in the latter the composition is more variable. The average content of major chemical constituents also is closely similar, partly because the large clay content of fine-grained offshore-marine shale is balanced by the small clay content of nearshore-marine siltstone and sandstone. In addition, the alumina and alkalic elements in an average of 10 percent more clay in marine rock are partly balanced by these constituents in the 5 percent more feldspar in nonmarine rock. Much of the observed regional and stratigraphic variation in maj or constituents is the result of the three major east-west migrations of the depositional sites of nearshore-marine sandstone and siltstone. Dolomite is found almost exclusively in relatively coarse-grained rock, particularly in nearshore-marine siltstone where diagenetic dolomite is expected, but it is found almost as frequently in nonmarine siltstone. Amounts of minor constituents are nearly equal in marine and nonmarine rocks, except that pyrite and consequently sulfur are relatively sparse in nonmarine rock. Average amounts of organic matter found in marine and nonmarine rocks are nearly identical. However, organic matter in nonmarine rock occurs almost entirely in volumetric

Preparation and Characterization of Novel Montmorillonite Nanocomposites

NASA Astrophysics Data System (ADS)

Mansa, Rola

Clay minerals have historically played a consequential role in human health. While the beginnings were rooted in geophagy, a primitive act of consuming earth, the health-related uses of clay minerals have evolved and diversified over time.. As excipients in pharmaceutical formulations, clay minerals can attribute novel properties onto intercalated compounds. Intercalating oxybenzone, a UV filter, within the interlamellar space of montmorillonite is desirable in order to minimize direct contact with skin. Intercalating resveratrol, a compound known for attributing beneficial effects onto human health, may be advantageous since this compound is susceptible to cis-trans isomerisation. The strategy of using alkylammonium--modified clay was undertaken and proved successful for the intercalation of oxybenzone. The field of biopolymer/layered silicate nanocomposites is heavily researched for use in a multitude of applications. Novel montmorillonite nanocomposites were prepared with neutral guar gum and cationic guar gum, using an environmentally friendly process and are fully characterized.

Antibacterial properties of Ag-exchanged Philippine natural zeolite-chitosan composites

NASA Astrophysics Data System (ADS)

Taaca, Kathrina Lois M.; Olegario, Eleanor M.; Vasquez, Magdaleno R.

2017-12-01

Zeolites are microporous minerals composed of silicon, aluminum and oxygen. These aluminosilicates consist of tetrahedral units which produce open framework structures to generate a system of pores and cavities of molecular dimensions. Zeolites are naturally abundant and can be mined in most parts of the world. In this study, natural zeolites (NaZ) which are locally-sourced here in the Philippines were investigated to determine its properties. An ion-exchange process was utilized, using the zeolite to silver (Ag) solution ratio of 1:20 (w/v), to incorporate Ag into the zeolite framework. Characterizations such as XRD, AAS, and Agar diffusion assay were used to evaluate the properties of the synthesized Ag-exchanged zeolites (AgZ). X-ray diffraction revealed that both NaZ and AgZ have peaks mostly corresponding to the clinoptilolite structure, with some trace peaks of the mordenite and quartz. Absorption spectroscopy revealed that the ion exchange process added about 0.61188g of silver into the zeolite structure. This Ag content was seen to be enough to make the AgZ sample exhibit an antibacterial effect where clearing zones against E. coli and S. aureus were observed in the agar diffusion assay, respectively. The AgZ sample was also tested as ceramic filler to a polymer matrix-chitosan. The diffusion assay revealed presence of antibacterial activity to the polymer composite with AgZ fillers. These results indicate that the Philippine natural zeolite, incorporated with metals such as Ag, can be used as an antibacterial agent and can be developed as a ceramic filler to improve the antibacterial property of composite materials for biomedical application.

An experimental study of basaltic glass-H2O-CO2 interaction at 22 and 50 ° C: Implications for subsurface storage of CO2

NASA Astrophysics Data System (ADS)

Galeczka, Iwona; Wolff-Boenisch, Domenik; Oelkers, Eric H.; Gislason, Sigurdur R.

2014-05-01

A novel high pressure column flow reactor (HPCFR) was used to investigate the evolution of fluid chemistry along a 2.3 meter flow path during 37-104 days of pure water- and CO2-charged water- (0.3 M CO2(aq)) basaltic glass interaction experiments at 22 and 50 ° C. The scale of the HPCFR, the ability to sample a reactive fluid at discrete spatial intervals under pressure and the possibility to measure the dissolved inorganic carbon and pH in situ all render the HPCFR unique in comparison with other reactors constructed for studies of CO2-charged water-rock interaction. During the pure water-basaltic glass interaction experiment, the pH of the injected water evolved rapidly from 6.7 to 9-9.5 and most of the dissolved iron was consumed by secondary mineral formation, similar to natural basaltic groundwater systems. In contrast to natural systems, however, the dissolved aluminium concentration remained relatively high along the entire flow path. The reactive fluid was undersaturated with respect to basaltic glass and carbonate minerals, but supersaturated with respect to zeolites, clays, and Fe hydroxides. Basaltic glass dissolution in the CO2-charged water was closer to stoichiometry than in pure water. The mobility of metals increased significantly in the reactive fluid and the concentration of some metals, including Mn, Fe, Cr, Al, and As exceeded the WHO (World Health Organisation) allowable drinking water limits. Iron was mobile and the aqueous Fe2+/Fe3+ ratio increased along the flow path. Basaltic glass dissolution in the CO2-charged water did not overcome the pH buffer capacity of the fluid. The pH rose only from an initial pH of 3.4 to 4.5 along the first 18.5 cm of the column, then remained constant during the remaining 2.1 meters of the flow path. Increasing the temperature of the CO2-charged fluid from 22 to 50 ° C increased the relative amount of dissolved divalent iron along the flow path. After a significant initial increase along the first metre of the column, the dissolved aluminium concentration decreased consistent with its incorporation into secondary minerals. The dissolved chromium concentration evolution mimicked that of Al at 50 ° C, suggesting substitution of trivalent Cr for Al in secondary phases. According to PHREEQC calculations, the CO2-charged fluid was always undersaturated with respect to carbonate minerals within the column, but supersaturated with respect to clays and Fe hydroxides at 22 ° C and with respect to clays and Al hydroxides at 50 ° C. Substantial differences were found between modelled and measured dissolved element concentrations in the fluids during the experiments. These differences underscore the need to improve computational models before they can be used to predict with confidence the fate and consequences of carbon dioxide injected into the subsurface.

Experimental Evaluation of pH and Temperature Effects on the Adsorption of Boron onto Clay Minerals

NASA Astrophysics Data System (ADS)

Hoenisch, B.; Marone, D.; Ruprecht, J.

2017-12-01

Modeling the secular evolution of the concentration [B] and isotopic composition (δ11B) of boron in seawater is hampered by limited constraints on the relative sources (i.e. riverine input of weathering products, hydrothermal convection at mid-ocean ridges and fluids expelled from accretionary prisms) and sinks (i.e. alteration of the oceanic crust, adsorption onto clays, and co-precipitation in carbonates) of boron to and from the ocean. Clays remove approximately 28% of total boron from the ocean and quantification of this sink thus represents a major factor for reconstructing the secular evolution of seawater [B] and δ11B over the Cenozoic. However, the relative strength of the clay sink could have been much smaller in the early Cenozoic compared to today, because borate ion as the charged species is preferentially adsorbed onto detrital clays over boric acid, and because the relative abundance of borate in seawater should have been lower under the more acidic conditions of the early Cenozoic. In addition, different clay minerals tend to fractionate boron isotopes differentially, and the relative composition of clay minerals has varied in the past with the dominant climate and weathering patterns on the continents. We have conducted a range of pH (7.5-8.4) and temperature (3-32°C) experiments with four clay minerals (Kaolinite, Illite, Montmorillonite and Chlorite), to build on previously published but limited experimental data. Similar to a previous study and as expected based on the relative abundance of borate ion in seawater, boron adsorption onto these clays increases at higher pH and lower temperatures, but whereas Montmorillonite and Illite absorb similar quantities of boron, Kaolinite is most and Chlorite least efficient in this process. We are now in the process of characterizing the boron isotope fractionation associated with these adsorption experiments.

Mild acid and alkali treated clay minerals enhance bioremediation of polycyclic aromatic hydrocarbons in long-term contaminated soil: A 14C-tracer study.

PubMed

Biswas, Bhabananda; Sarkar, Binoy; Rusmin, Ruhaida; Naidu, Ravi

2017-04-01

Bioremediation of polycyclic aromatic hydrocarbon (PAH)-contaminated soils requires a higher microbial viability and an increased PAH bioavailability. The clay/modified clay-modulated bacterial degradation could deliver a more efficient removal of PAHs in soils depending on the bioavailability of the compounds. In this study, we modified clay minerals (smectite and palygorskite) with mild acid (HCl) and alkali (NaOH) treatments (0.5-3 M), which increased the surface area and pore volume of the products, and removed the impurities without collapsing the crystalline structure of clay minerals. In soil incubation studies, supplements with the clay products increased bacterial growth in the order: 0.5 M HCl ≥ unmodified ≥ 0.5 M NaOH ≥ 3 M NaOH ≥ 3 M HCl for smectite, and 0.5 M HCl ≥ 3 M NaOH ≥ 0.5 M NaOH ≥ 3 M HCl ≥ unmodified for palygorskite. A 14 C-tracing study showed that the mild acid/alkali-treated clay products increased the PAH biodegradation (5-8%) in the order of 0.5 M HCl ≥ unmodified > 3 M NaOH ≥ 0.5 M NaOH for smectite, and 0.5 M HCl > 0.5 M NaOH ≥ unmodified ≥ 3 M NaOH for palygorskite. The biodegradation was correlated (r = 0.81) with the bioavailable fraction of PAHs and microbial growth as affected particularly by the 0.5 M HCl and 0.5 M NaOH-treated clay minerals. These results could be pivotal in developing a clay-modulated bioremediation technology for cleaning up PAH-contaminated soils and sediments in the field. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of zeolite on toxicity of ammonia in freshwater sediments: Implications for toxicity identification evaluation procedures

USGS Publications Warehouse

Besser, J.M.; Ingersoll, C.G.; Leonard, E.N.; Mount, D.R.

1998-01-01

Techniques for reducing ammonia toxicity in freshwater sediments were investigated as part of a project to develop toxicity identification and evaluation (TIE) procedures for whole sediments. Although ammonia is a natural constituent of freshwater sediments, pollution can lead to ammonia concentrations that are toxic to benthic invertebrates, and ammonia can also contribute to the toxicity of sediments that contain more persistent contaminants. We investigated the use of amendments of a natural zeolite mineral, clinoptilolite, to reduce concentrations of ammonia in sediment pore water. Zeolites have been widely used for removal of ammonia in water treatment and in aqueous TIE procedures. The addition of granulated zeolite to ammonia-spiked sediments reduced pore-water ammonia concentrations and reduced ammonia toxicity to invertebrates. Amendments of 20% zeolite (v/v) reduced ammonia concentrations in pore water by ???70% in spiked sediments with ammonia concentrations typical of contaminated freshwater sediments. Zeolite amendments reduced toxicity of ammonia-spiked sediments to three taxa of benthic invertebrates (Hyalella azteca, Lumbriculus variegatus, and Chironomus tentans), despite their widely differing sensitivity to ammonia toxicity. In contrast, zeolite amendments did not reduce acute toxicity of sediments containing high concentrations of cadmium or copper or reduce concentrations of these metals in pore waters. These studies suggest that zeolite amendments, used in conjunction with toxicity tests with sensitive taxa such as H. azteca, may be an effective technique for selective reduction of ammonia toxicity in freshwater sediments.

Clay mineral distribution and provenance in the Heuksan mud belt, Yellow Sea

NASA Astrophysics Data System (ADS)

Cho, Hyen Goo; Kim, Soon-Oh; Kwak, Kyeong Yoon; Choi, Hunsoo; Khim, Boo-Keun

2015-12-01

The Heuksan mud belt (HMB), located in the southeastern Yellow Sea, runs parallel to the southwest coast of Korea. In this study, the distribution and relative contribution of four major clay minerals are investigated using 101 surface sediment samples collected in the course of KIOST (2001, 2010, 2011) and KIGAM (2012) cruises, as well as 33 river sediment samples (four from the Huanghe River, three from the Changjiang River, and 26 from Korean rivers) in order to clarify the provenance of fine-grained sediments in the HMB. Based on this currently largest and most robust dataset available for interpretation, the clay mineral assemblages of the fine-grained sediments in the HMB are found to be on average composed of 64.7% illite, 17.9% chlorite, 11.4% kaolinite, and 5.9% smectite. Overall, the clay mineral assemblages are similar in both the northern and the southern parts of the HMB, although smectite seems to be relatively enriched in the southern part, whereas kaolinite is slightly more dominant in the northern part. This clearly indicates that the clays are mostly derived from Korean rivers and, in the southern part of the HMB, partly also from the Huanghe River in China. The new data thus confirm and strengthen the tentative interpretation of some earlier work based on a more limited dataset.

Mineralogical Characterization of the Miocene Olcese Formation, Southern San Joaquin Valley, California

NASA Astrophysics Data System (ADS)

Lopez, K. A.; Baron, D.; Guo, J.; Woolford, J. M.

2016-12-01

The early to middle Miocene Olcese Formation in the southern San Joaquin Valley of California consists of shallow marine shelf sands in its lower and upper parts, and non-marine, frequently pumiceous sands in its middle part, and varies in thickness up to 1800 ft. There is little known as to the origin, nature, quantity, and distribution of clay minerals throughout the formation. This study examined 95 sidewall core samples from three wells, as well as 388 cutting samples from four wells and 12 samples from 3 outcrops. Well samples were from depths between 1,800 and 4,000 ft. Qualitative and quantitative mineralogy including clay minerals of the sidewall samples and selected cutting samples was determined by powder X-ray diffraction (XRD). XRD analyses were supplemented by scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS) and petrographic microscopy of selected samples. The main minerals of bulk samples include composite clay, quartz, potassium feldspar/plagioclase, calcite, and clinoptilolite. Content of composite clay varies between 17% and 51%. The clay-size fraction is predominantly composed of smectite, illite, kaolinite and chlorite with smectite being the most abundant. Smectite and clinoptilolite may be the alteration products of deeper burial of volcanic materials. The formation permeability could be significantly lowered by these authigenic minerals.

Modified clay minerals efficiency against chemical and biological warfare agents for civil human protection.

PubMed

Plachá, Daniela; Rosenbergová, Kateřina; Slabotínský, Jiří; Kutláková, Kateřina Mamulová; Studentová, Soňa; Martynková, Gražyna Simha

2014-04-30

Sorption efficiencies of modified montmorillonite and vermiculite of their mono ionic Na and organic HDTMA and HDP forms were studied against chemical and biological warfare agents such as yperite and selected bacterial strains. Yperite interactions with modified clay minerals were observed through its capture in low-density polyethylene foil-modified clay composites by measuring yperite gas permeation with using chemical indication and gas chromatography methods. The antibacterial activities of synthetized organoclays were tested against selected Gram-positive and Gram-negative bacterial species in minimum inhibitory concentration tests. The obtained results showed a positive influence of modified clay minerals on the significant yperite breakthrough-time increase. The most effective material was the polyethylene-Na form montmorillonite, while the polyethylene-Na form vermiculite showed the lowest efficiency. With increasing organic cations loading in the interlayer space the montmorillonite efficiency decreased, and in the case of vermiculite an opposite effect was observed. Generally the modified montmorillonites were more effective than modified vermiculites. The HDP cations seem to be more effective compare to the HDTMA. The antibacterial activity tests confirmed efficiency of all organically modified clay minerals against Gram-positive bacteria. The confirmation of antibacterial activity against Y. pestis, plague bacteria, is the most interesting result of this part of the study. Copyright © 2014 Elsevier B.V. All rights reserved.

Use of zeolite to neutralise nickel in a soil environment.

PubMed

Boros-Lajszner, Edyta; Wyszkowska, Jadwiga; Kucharski, Jan

2017-12-30

Nickel is a heavy metal which is a stable soil pollutant which is difficult to remediate. An attempt to reduce its impact on the environment can be made by changing its solubility. The right level of hydrogen ions and the content of mineral and organic colloids are crucial in this regard. Therefore, methods to neutralise heavy metals in soil are sought. There are no reports in the literature on the possibility of using minerals in the detoxication of a soil environment contaminated with metals. It is important to fill the gap in research on the effect of zeolites on the microbiological, biochemical and physicochemical properties of soils under pressure from heavy metals. Therefore, a pot experiment was conducted on two soils which examined the effect of various levels of contamination of soil with nickel on the activity of soil enzymes, physical and chemical properties and growth and development of plants. An alleviating effect of zeolite Bio.Zeo.S.01 on the negative impact of nickel on the soil and a plant (oats) was examined. The enzyme activity and the oat yield were found to be significantly and negatively affected by an excess of nickel in the soil, regardless of the soil type. The metal was accumulated more in the oat roots than in the above-ground parts. An addition of zeolite decreased the level of accumulation of nickel in oats grown only on sandy-silty loam. Zeolite Bio.Zeo.S.01 used in the study only slightly alleviated the negative effect of nickel on the biochemical properties of soil. Therefore, its usability in the remediation of soil contaminated with nickel is small.

Clay minerals in sediments of Portuguese reservoirs and their significance as weathering products from over-eroded soils: a comparative study of the Maranhão, Monte Novo and Divor Reservoirs (South Portugal)

NASA Astrophysics Data System (ADS)

Fonseca, Rita M. F.; Barriga, Fernando J. A. S.; Conceição, Patrícia I. S. T.

2010-12-01

The Southern region of Portugal is subjected to several forms of over-erosion. Most leached products, mainly composed of fine particles containing nutrients, metals or pesticides, are easily transported by river flows. When these are hindered by a physical barrier such as a dam, the particulate load accumulates on the bottom of the reservoirs, often leading to a pronounced decrease of water quality. Bottom sediments from three reservoirs were subjected to grain-size analysis and a study of clay minerals by X-ray diffraction. Most sediments contain a diverse set of clay minerals, mostly illites, smectites, chlorites and kaolinites. The nature of the clay minerals reflects the nature of the parent rocks. During the cycles of transport and temporary deposition, they may undergo significant chemical and physical transformations, which lead to an increase of expandable properties and therefore, to a higher cationic exchange capacity, determining its important role as vehicles of environmental pollutants.

The source of dissolved silicon in soil surface solutions of a temperate forest ecosystem: Ge/Si and Si isotope ratios as biogeochemical tracers

NASA Astrophysics Data System (ADS)

Cornelis, J.; Delvaux, B.; Cardinal, D.; André, L.; Ranger, J.; Opfergelt, S.

2010-12-01

Understand the biogeochemical cycle of silicon (Si) in the Earth’s critical zone and the dissolved Si transfer from the litho-pedosphere into the hydrosphere is of great interest for the global balance of biogeochemical processes, including the global C cycle. Indeed, the interaction between Si and C cycles regulates the atmospheric CO2 through the chemical weathering of silicate minerals, the C sequestration in stable organo-mineral compounds and the Si nutrition of phytoplankton CO2-consumers in oceans. H4SiO4 released by mineral dissolution contributes to the critical zone evolution through neoformation of secondary minerals, adsorption onto hydroxyl-bearing phases and recycling by vegetation and return of phytoliths on topsoil. The neoformation of secondary precipitates (clay minerals and phytoliths polymerized in plants) and adsorption of Si onto Fe and Al (hydr)oxides are processes favoring the light Si isotope incorporation, generating rivers enriched in heavy Si isotopes. On the other hand, clay minerals and phytoliths display contrasting Ge/Si ratios since clay-sized weathering products are enriched in Ge and phytoliths are depleted in Ge. Thus stable Si isotope and Ge/Si ratios constitute very interesting proxies to trace transfer of Si in the critical zone. Here we report Si isotopic and Ge/Si ratios of the different Si pools in a temperate soil-tree system (Breuil experimental forest, France) involving various tree species grown on Alumnic Cambisol derived from granitic bedrock. Relative to granitic bedrock (δ30Si = -0.07 ‰; Ge/Si = 2.5 µmol/mol), clay-sized minerals are enriched in 28Si (-1.07 ‰) and Ge (6.2 µmol/mol) while phytoliths are enriched in 28Si (-0.28 to -0.64 ‰) and depleted in Ge (0.1 to 0.3 µmol/mol). This contrast allows us to infer the relative contribution of litho/pedogenic and biogenic mineral dissolution on the release of H4SiO4 in soil surface solutions. The Si-isotope signatures and Ge/Si ratios of forest floor solutions evolve towards lighter values (-1.38 and -2.05 ‰) and higher Ge/Si ratios (2.7 µmol/mol) relative to granite bedrock. This suggests a partial dissolution of 28Si and Ge-enriched secondary clays minerals incorporated by bioturbation in organic-rich horizons, with a fractionation releasing preferentially light Si isotopes. Without considering that organic acids promote dissolution of minerals, clay minerals detected in the organic layer (vermiculite, chlorite, illite and Ca-montmorillonite) are not stable and could have been partially dissolved and transformed in the chemical environment of forest floor. Sources of H4SiO4 in forest floor solutions are influenced by tree species which control the extent of clay-sized minerals mixed in organic horizons by bioturbation and, to a lesser extent, the Si recycling by forest vegetation.

Depositional and diagenetic processes of Qa Khanna playa, North Jordan basaltic plateau, Jordan

NASA Astrophysics Data System (ADS)

Howari, F. M.; Banat, K. M.; Abu-Salha, Y. A.

2010-09-01

The present study explored mineral occurrences and sediment characteristics of playas from northern Jordan and explained depositional and diagenetic processes as reflected from bulk chemistry and sedimentary structures. Mudcracks of different sizes and shape patterns, laminations, intersediment vesicles, and bioturbation pipes are the main sedimentary structures. Plagioclase, olivine, orthopyroxene, nepheline and other opaque minerals are all of detrital origin, and are derived from the basaltic bedrocks surrounding the studied playa. Evaporites are very rare; they are represented only by trace amounts of gypsum. The identified clay minerals in the clay fraction of the studied sediments, arranged according to their decreasing abundances are palygorskite, illite, kaolinite, smectite and chlorite. The elemental abundances were tied to clay, CaCO 3 and nearby igneous rocks. The type of clay minerals, the high pH values of the studied sediments, and the considerable incorporation of Mg and K in palygorskite and illite respectively, may strongly reflect a high evaporative and alkaline environment under arid to semi-arid conditions in an ephemeral lake of the Qa Khanna. Concentrations and distributions of both major and trace elements are essentially controlled by the clay mineralogy and the calcium carbonate content; Ca is mainly incorporated in the CaCO 3, which is either generated authigenically or by aeolian deposition. Fe and K are incorporated and fixed by illite under an evaporative and alkaline environment. Mg is incorporated in palygorskite while Mn is adsorbed on various clay minerals. Sr substitutes for Ca in the aeolian CaCO 3 and its presence in the studied sediments is independent of the prevailing conditions during the playa evolution. Rb substitutes for K in illite under the prevailing chemical conditions in the studied playa.

Examination and Manipulation of Clay Aggregates - Initial Inquiry

DTIC Science & Technology

2011-06-06

and the first conclusions in the examination and testing of clay aggregates composed of montmorillonite clay and a polysaccharide (xanthan gum, also...and the first conclusions in the examination and testing of clay aggregates composed of montmorillonite clay and a polysaccharide (xanthan gum, also...PSU and the X-gum content from 0% to 10% of the mineral content of the clay (by weight). Montmorillonite was used in all the suspensions prepared

Ball clay

USGS Publications Warehouse

Virta, R.L.

2007-01-01

The article offers information on ball clay. Among the companies that mine ball clay in the U.S. are H.C. Spinks Clay, Kentucky-Tennessee Clay and Old Hickory Clay. In 2006, an estimated 1.2 million tons of the mineral was sold or used domestically and exported. Forty-percent of the total sales is accounted for ceramic floor and wall tile followed by sanitaryware and miscellaneous ceramics. Its average value was $ 45 per ton in 2006.

Effects of simulated clay gouges on the sliding behavior of Tennessee sandston

NASA Astrophysics Data System (ADS)

Shimamoto, Toshihiko; Logan, John M.

1981-06-01

The effects of simulated fault gouge on the sliding behavior of Tennessee sandstone are studied experimentally with special reference to the stabilizing effect of clay minerals mixed into the gouge. About 30 specimens with gouge composed of pure clays, of homogeneously mixed clay and anhydrite, or of layered clay and anhydrite, along a 35° precut are deformed dry in a triaxial apparatus at a confining pressure of 100 MPa, with a shortening rate of about 5 · 10 -4/sec, and at room temperature. Pure clay gouges exhibit only stable sliding, and the ultimate frictional strength is very low for bentonite (mont-morillonite), intermediate for chlorite and illite, and considerably higher for kaolinite. Anhydrite gouge shows violent stick-slip at 100 MPa confining pressure. When this mineral is mixed homogeneously with clays, the frictional coefficient of the mixed gouge, determined at its ultimate frictional strength, decreases monotonically with an increase in the clay content. The sliding mode changes from stick-slip to stable sliding when the frictional coefficient of the mixed clay-anhydrite gouge is lowered down below 90-95% of the coefficient of anhydrite gouge. The stabilizing effect of clay in mixed gouge is closely related to the ultimate frictional strength of pure clays; that is, the effect is conspicuous only for a mineral with low frictional strength. Only 15-20% of bentonite suppresses the violent stick-slip of anhydrite gouge. In contrast, violent stick-slip occurs even if the gouge contains as much as 75% of kaolinite. The behavior of illite and chlorite is intermediate between that of kaolinite and bentonite. Bentonite—anhydrite two-layer gouge exhibits stable sliding even when the bentonite content is only 5%. Thus, the presence of a thin, clay-rich layer in a fault zone stabilizes the behavior much more effectively than do the clay minerals mixed homogeneously with the gouge. This result brings out the mechanical significance of internal structures of a fault zone in understanding the effects of intrafault materials on the fault motion. Based on the present experimental results incorporated with some other experimental data, it is argued that although the stabilizing effect of montmorillonite and vermiculite is indeed remarkable at room temperature, the effect should be much less pronounced at elevated temperatures, due perhaps to the dewatering of the clays. In most geological environments where shallow earthquakes occur, the stabilizing effect of clays is probably not so conspicuous as to completely suppress the unstable motion of a fault.

Thallium (Tl) sorption onto illite and smectite: Implications for Tl mobility in the environment

NASA Astrophysics Data System (ADS)

Martin, Loïc A.; Wissocq, Aubéry; Benedetti, M. F.; Latrille, Christelle

2018-06-01

Clay minerals play a relevant role in the transport and fate of trace elements in the environment. Though illite has been referred as an important Thallium (Tl) bearing phase in soils, mechanisms and affinity of thallium for clay minerals remain poorly known. This study investigated the sorption behavior of thallium as Tl(I) onto illite and smectite, two clay minerals occurring mainly in soils and sediments. Different sorption experiments were carried out under various pH conditions and Tl concentrations, in competition with sodium and calcium at a constant ionic strength of 0.01 mol L-1. Our results showed that illite displayed more affinity than smectite for thallium. With illite, the distribution coefficients (Kd in L kg-1) varied between 102.75 ± 0.17 and 104.0 ± 0.17 in Na solutions versus between 102.25 ± 0.17 and 103.0 ± 0.17 in Ca solutions, depending on pH. With smectite, Kd (in L kg-1) ranged between 102.50 ± 0.16 and 103.20 ± 0.16 and between 101.25 ± 0.16 and 101.95 ± 0.16 in Na and Ca solutions, respectively. Sorption behavior was described with the Multi-Site Ion Exchanger model and selectivity coefficients with respect to protons were calculated for the first time. In all cases, independently of clay mineral and background electrolyte, low capacity but highly reactive sites were dominant in thallium uptake, highlighting Tl affinity for those sites. Moreover, the exchangeable and reversible interactions between Tl+ and clays reactive sites suggested that in changing conditions, thallium could be released in solution. The role of clay minerals in thallium environmental cycle is evident and confirmed illite to be a dominant Tl bearing phase, in some environment competing with manganese oxides. Compared to others Tl bearing mineral phases, clays are ranked as follows: MnO2 > illite > smectite ∼ ferrihydrite ≥ Al2O3 ∼ goethite > SiO2. Finally, over the three monovalent cations (Tl, Rb, Cs) Tl is the one less sorbed on illite independently of the background cations.

Clay mineralogy and source-to-sink transport processes of Changjiang River sediments in the estuarine and inner shelf areas of the East China Sea

NASA Astrophysics Data System (ADS)

Zhao, Yifei; Zou, Xinqing; Gao, Jianhua; Wang, Chenglong; Li, Yali; Yao, Yulong; Zhao, Wancang; Xu, Min

2018-02-01

We examined the source-to-sink sediment transport processes from the Changjiang River to the estuarine coastal shelf area by analyzing the clay mineral assemblages in suspended sediment samples from the Changjiang River catchment and surface samples from the estuarine coastal shelf area following the impoundment of the Three Gorges Dam (TGD) in 2003. The results indicate that the clay mineral compositions throughout the study area are dominated by illite, with less abundant kaolinite and chlorite and scarce smectite. The clay minerals display distinct differences in the tributaries and exhibit obvious changes in the trunk stream compared with the periods before 2003, and the source of sediment has largely shifted to the mid- to lower reaches of the river after 2003. Spatially, the clay mineral assemblages in the estuarine area define two compositionally distinct provinces. Province I covers the mud area of the Changjiang River estuary and the Zhe-Min coastal region, where sediment is primarily supplied by the Changjiang River. Province II includes part of the Changjiang River estuary and the southeastern portion of the study area, where the sediment is composed of terrestrial material from the Changjiang River and re-suspended material from the Huanghe River carried by the Jiangsu coastal current. Moreover, the other smaller rivers in China (including the Oujiang and Minjiang rivers of mainland China and the rivers of West Taiwan) also contribut sediments to the estuarine and inner shelf areas. In general, the clay mineral assemblages in the Changjiang River estuarine area are have mainly been controlled by sediment supplied from upstream of the Changjiang River tributaries. However, since the completion of the TGD in 2003, the mid- to downstream tributaries have become the main source of sediments from the Changjiang catchment into the East China Sea. These analyses further demonstrate that the coastal currents and the decrease in the sediment load of the river have the greatest impacts on the distribution and transport of clay minerals assemblages in the sediments.

Common clay and shale

USGS Publications Warehouse

Virta, R.L.

2003-01-01

Part of the 2002 industrial minerals review. The production, consumption, and price of shale and common clay in the U.S. during 2002 are discussed. The impact of EPA regulations on brick and structural clay product manufacturers is also outlined.

Clays, common

USGS Publications Warehouse

Virta, R.L.

1998-01-01

Part of a special section on the state of industrial minerals in 1997. The state of the common clay industry worldwide for 1997 is discussed. Sales of common clay in the U.S. increased from 26.2 Mt in 1996 to an estimated 26.5 Mt in 1997. The amount of common clay and shale used to produce structural clay products in 1997 was estimated at 13.8 Mt.

Alteration, adsorption and nucleation processes on clay-water interfaces: Mechanisms for the retention of uranium by altered clay surfaces on the nanometer scale

NASA Astrophysics Data System (ADS)

Schindler, Michael; Legrand, Christine A.; Hochella, Michael F.

2015-03-01

Nano-scale processes on the solid-water interface of clay minerals control the mobility of metals in the environment. These processes can occur in confined pore spaces of clay buffers and barriers as well as in contaminated sediments and involve a combination of alteration, adsorption and nucleation processes of multiple species and phases. This study characterizes nano-scale processes on the interface between clay minerals and uranyl-bearing solution near neutral pH. Samples of clay minerals with a contact pH of ∼6.7 are collected from a U mill and mine tailings at Key Lake, Saskatchewan, Canada. The tailings material contains Cu-, As-, Co-, Mo-, Ni-, Se-bearing polymetallic phases and has been deposited with a surplus of Ca(OH)2 and Na2CO3 slaked lime. Small volumes of mill-process solutions containing sulfuric acid and U are occasionally discharged onto the surface of the tailings and are neutralized after discharge by reactions with the slaked lime. Transmission electron microscopy (TEM) in combination with the focused ion beam (FIB) technique and other analytical methods (SEM, XRD, XRF and ICP-OES) are used to characterize the chemical and mineralogical composition of phases within confined pore spaces of the clay minerals montmorillonite and kaolinite and in the surrounding tailings material. Alteration zones around the clay minerals are characterized by different generations of secondary silicates containing variable proportions of adsorbed uranyl- and arsenate-species and by the intergrowth of the silicates with the uranyl-minerals cuprosklodowskite, Cu[(UO2)2(SiO3OH)2](H2O)6 and metazeunerite, Cu[(UO2)(AsO4)2](H2O)8. The majority of alteration phases such as illite, illite-smectite, kaolinite and vermiculite have been most likely formed in the sedimentary basin of the U-ore deposit and contain low amounts of Fe (<5 at.%). Iron-enriched Al-silicates or illite-smectites (Fe >10 at.%) formed most likely in the limed tailings at high contact pH (∼10.5) and their structure is characterized by a low degree of long-range order. Adsorption of U and nucleation of metazeunerite and cuprosklodowskite are strongly controlled by the presence of the adsorbed oxy-anion species arsenate and silica on the Fe-enriched silicates. Heterogeneous nucleation of nano-crystals of the uranyl minerals occurs most likely on adsorption sites of binary uranyl-, arsenate- and silica-complexes as well as on ternary uranyl-arsenate or uranyl-silicate complexes. The uranyl minerals occur as aggregates of misoriented nano-size crystals and are the result of supersaturated solutions and a high number of nucleation sites that prevented the formation of larger crystals through Oswald ripening. The results of this study provide an understanding of interfacial nano-scale processes between uranyl species and altered clay buffers in a potential Nuclear Waste repository as similar alteration conditions of clays may occur in a multi-barrier system.

a Mineralogical Analysis of Hspdp Core Samples from the Northern Awash Pliocene Hadar Formation, Ethiopia: the tale of AN East African Paleolake

NASA Astrophysics Data System (ADS)

Davis, D. M.; Deocampo, D.; Rabideaux, N. M.; Campisano, C. J.

2017-12-01

The Northern Awash Valley is located in the southwestern portion of the Afar Depression in Ethiopia. During the 2014 field season, two core sites were drilled as part of the Hominin Sites and Paleolakes Drilling Project (HSPDP), recovering a total of 600 m of sediment from both localities (NAO and NAW). Mineralogical analyses of the bulk sediments and clays from the Hadar Formation have helped to begin constructing a more complete picture of the paleoenvironmental conditions of the Northern Awash during the Pliocene. This work is an attempt to begin to answer the questions about salinity/alkalinity of Hadar Paleolake as well as its sulfur content. The two sites, NAW and NAO, are about 3 kilometers apart and presumably part of the same paleolake basin. The data has shown that this area was much more humid during the Pliocene than it is today and that most of the minerals in the paleolake basin are detrital, save for calcite, Mg-calcite, gypsum, pyrite, and a few zeolites. 060 analyses of the clays in the cores show that the lake was a freshwater lake three million years ago, up until its eventual evaporation. Interestingly, the lack of trioctahedral clays is an indication that the lake water did not become highly saline and alkaline during its evaporation. An interesting contrast between the two cores shows that NAO contains gypsum, but so far, no pyrite. NAW, on the other hand, contains both pyrite and gypsum. The pyrite in NAW is mostly at the bottom of the core, whereas, the gypsum is intermittent throughout the core and much more sparse toward the bottom. This line of evidence suggests that the two sites within the lake may have experienced different redox conditions. It may be that the NAO core was sampled in a shallower part of the lake whereas the NAW core sampled a deeper section.

Chew Bahir: A Key Site within the Hominin Sites and Paleolakes Drilling Project, towards a Half Million-Year Climate Record from Southern Ethiopia

NASA Astrophysics Data System (ADS)

Schaebitz, F.; Asrat, A.; Lamb, H. F.; Trauth, M. H.; Foerster, V. E.; Junginger, A.; Raub, T. D.; Gromig, R.; Viehberg, F. A.; Roberts, H. M.; Cohen, A.

2015-12-01

Chew Bahir, a saline mudflat today, is one of the five sites in East Africa, drilled within the framework of HSPDP (Hominin Site and Paleolakes Drilling Project). It is also one of the key sites of the Collaborative Research Centre (CRC-806) "Our way to Europe" aiming at the reconstruction of environmental conditions in the source region of modern man (H. sapiens). It is suggested that a changing environment could have triggered the mobility and dispersal of modern man. The oldest known fossils of anatomical modern humans (~195 ka BP) were found in the Omo basin, not more than 90km westwards of our drill site. The deposits in the tectonic basin of Chew Bahir in southern Ethiopia were cored in Nov. 2014 in two boreholes down to 280 m and 260 m below surface respectively. The overlapping long cores (drilled ~20 m apart from each other), were opened, scanned, described and sampled in low resolution in April 2015. The recovered sediments mostly contain green-greyish to light coloured and brown to reddish clays and silty clays, interbedded with some laminated mica-rich sand layers and occurrences of carbonate concretions and nodules, which decrease upcore. Here we will present a first set of results on the composite core, comprising mainly lithology and magnetic susceptibility (MS). Based on known sedimentation rates from pre-studies performed on short cores across the basin, we anticipate the deep drilled cores to cover at least 500 ka BP. Moreover, new insights into the role of post-depositional alteration, especially of clay minerals and zeolites, will be presented as a contribution to an improved understanding of formation processes. The results support the identification of wet and dry climate periods in the past. Those pronounced variations of moisture availability, are thought to have influenced the evolution and mobility of Homo sapiens sapiens.

Preliminary report on the clay mineralogy of the Upper Devonian Shales in the southern and middle Appalachian Basin

USGS Publications Warehouse

Hosterman, John W.; Loferski, Patricia J.

1978-01-01

The distribution of kaolinite in parts of the Devonian shale section is the most significant finding of this work. These shales are composed predominately of 2M illite and illitic mixed-layer clay with minor amounts of chlorite and kaolinite. Preliminary data indicate that kaolinite, the only allogenic clay mineral, is present in successively older beds of the Ohio Shale from south to north in the southern and middle parts of the Appalachian basin. This trend in the distribution of kaolinite shows a paleocurrent direction to the southwest. Three well-known methods of preparing the clay fraction for X-ray diffraction analysis were tested and evaluated. Kaolinite was not identified in two of the methods because of layering due to differing settling rates of the clay minerals. It is suggested that if one of the two settling methods of sample preparation is used, the clay film be thin enough for the X-ray beam to penetrate the entire thickness of clay.

Geochemical survey of the Adams Gap and Shinbone Creek Roadless Areas, Clay County, Alabama

USGS Publications Warehouse

Robinson, G.R.; Klein, T.L.; Lesure, F.G.; Hanley, J.T.

1984-01-01

Reports covering the mineral resources of Clay County and vicinity include Brewer (1896) and Adams (1930) on gold, Prouty (1923) on graphite, and Heinrich and Olson (1953) on mica. The mineral resources of the Talladega National Forest were evaluated by Gilbert and Smith (1973). The mineral resource potential of the two roadless areas is detailed in Robinson and others (1983) and an accompanying geologic report is given in Robinson and others (in press).

Sensitive life detection strategies for low-biomass environments: optimizing extraction of nucleic acids adsorbing to terrestrial and Mars analogue minerals.

PubMed

Direito, Susana O L; Marees, Andries; Röling, Wilfred F M

2012-07-01

The adsorption of nucleic acids to mineral matrixes can result in low extraction yields and negatively influences molecular microbial ecology studies, in particular for low-biomass environments on Earth and Mars. We determined the recovery of nucleic acids from a range of minerals relevant to Earth and Mars. Clay minerals, but also other silicates and nonsilicates, showed very low recovery (< 1%). Consequently, optimization of DNA extraction was directed towards clays. The high temperatures and acidic conditions used in some methods to dissolve mineral matrices proved to destruct DNA. The most efficient method comprised a high phosphate solution (P/EtOH; 1 M phosphate, 15% ethanol buffer at pH 8) introduced at the cell-lysing step in DNA extraction, to promote chemical competition with DNA for adsorption sites. This solution increased DNA yield from clay samples spiked with known quantities of cells up to nearly 100-fold. DNA recovery was also enhanced from several mineral samples retrieved from an aquifer, while maintaining reproducible DGGE profiles. DGGE profiles were obtained for a clay sample for which no profile could be generated with the standard DNA isolation protocol. Mineralogy influenced microbial community composition. The method also proved suitable for the recovery of low molecular weight DNA (< 1.5 kb). © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

Clay mineral continental amplifier for marine carbon sequestration in a greenhouse ocean.

PubMed

Kennedy, Martin J; Wagner, Thomas

2011-06-14

The majority of carbon sequestration at the Earth's surface occurs in marine continental margin settings within fine-grained sediments whose mineral properties are a function of continental climatic conditions. We report very high mineral surface area (MSA) values of 300 and 570 m(2) g in Late Cretaceous black shales from Ocean Drilling Program site 959 of the Deep Ivorian Basin that vary on subcentennial time scales corresponding with abrupt increases from approximately 3 to approximately 18% total organic carbon (TOC). The observed MSA changes with TOC across multiple scales of variability and on a sample-by-sample basis (centimeter scale), provides a rigorous test of a hypothesized influence on organic carbon burial by detrital clay mineral controlled MSA. Changes in TOC also correspond with geochemical and sedimentological evidence for water column anoxia. Bioturbated intervals show a lower organic carbon loading on mineral surface area of 0.1 mg-OC m(-2) when compared to 0.4 mg-OC m(-2) for laminated and sulfidic sediments. Although either anoxia or mineral surface protection may be capable of producing TOC of < 5%, when brought together they produced the very high TOC (10-18%) apparent in these sediments. This nonlinear response in carbon burial resulted from minor precession-driven changes of continental climate influencing clay mineral properties and runoff from the African continent. This study identifies a previously unrecognized land-sea connection among continental weathering, clay mineral production, and anoxia and a nonlinear effect on marine carbon sequestration during the Coniacian-Santonian Oceanic Anoxic Event 3 in the tropical eastern Atlantic.

Geochemical and technological characterization of clays of Corumbataí Formation, Paraná Basin, in the state of São Paulo, Brazil for the application in the ceramic industry.

NASA Astrophysics Data System (ADS)

Christofoletti, Sergio Ricardo; Torres Moreno, Maria Margarita; Batezelli, Alessandro; Zanardo, Antenor

2014-05-01

The Corumbataí Formation is a geological unit of the Paraná Basin comprises a range of predominantly argillaceous facies. These clays are important from an economic point of view, because they represent important mineral deposits suppliers of raw materials for the ceramic industry in the production of ceramic tiles.The study presents preliminary results of a research that aims to study the clays municipalities Tambaú, Ferreira and Santa Rosa of Viterbo in the State of São Paulo for their application and diversification of ceramic products. The methodology used was based on a detailed description of facies using the methodology in principles of analysis of Basin Miall (1984), followed by mineralogical identification by X-ray Diffraction, chemical analysis of major elements by X-ray Fluorescence and technological tests ceramic. According to the geological surveys of mines studied through columnar sections were identified the following lithofacies from base to top: Massive, Laminated, Intercalated and Altered. The mineralogy present on these lithofacies is composed by minerals: quartz, microclineo, albite, calcite, dolomite and hematite and by clay minerals illite, kaolinite and montmorillonite. The quartz represents the mineral more present in diffraction and occurs with d001 of 3.33Å in all lithofacies studied. The illite clay mineral represents the most frequent in studied samples presenting d 001 10Å in three conditions (natural, heated and treated with ethylene glycol) in which the blade was subjected to the analysis of X-ray diffraction, the presence of kaolinite or montmorillonite occurs or not in samples. It was observed a increased frequency of some minerals in the lithofacies studied, carbonates (calcite and dolomite), hematite and feldspar occurring in the intermediate portions of the profile with a predominance in lithofacies Intercalated. The illita clay mineral occurs throughout the profile, but with greater frequency in the lithofacies Massive and Laminated. The clay minerals kaolinite and montmorillonite occur in portions intermediate and top of the profiles studied in the intercalated and altered lithofacies. The chemical results of major elements by X-ray fluorescence confirmed the mineralogical results, with average values of 63.74 % of SiO2, 12.50 of Al2O3, 4.35% of of K2O, 0.45% of Na2O, 2,72% of CaO and 1,87 of MgO. The results chemical and mineralogical subsidized testing and ceramic formulations due to be executed later so defining the main applications of these clays in the production of ceramic products. The authors acknowledge the finantial support of Fundação de Amparo à Pesquisa do Estado de São Paulo-FAPESP, (Process, number 2012/24219-9).

A granulometry and secondary mineral fingerprint of chemical weathering in periglacial landscapes and its application to blockfield origins

NASA Astrophysics Data System (ADS)

Goodfellow, Bradley W.

2012-12-01

A review of published literature was undertaken to determine if there was a fingerprint of chemical weathering in regoliths subjected to periglacial conditions during their formation. If present, this fingerprint would be applied to the question of when blockfields in periglacial landscapes were initiated. These blocky diamicts are usually considered to represent remnants of regoliths that were chemically weathered under a warm, Neogene climate and therefore indicate surfaces that have undergone only a few metres to a few 10s of metres of erosion during the Quaternary. Based on a comparison of clay and silt abundances and secondary mineral assemblages from blockfields, other regoliths in periglacial settings, and regoliths from non-periglacial settings, a fingerprint of chemical weathering in periglacial landscapes was identified. A mobile regolith origin under, at least seasonal, periglacial conditions is indicated where clay(%) ≤ 0.5*silt(%) + 8 across a sample batch. This contrasts with a mobile regolith origin under non-periglacial conditions, which is indicated where clay(%) ≥ 0.5*silt(%) - 6 across a sample batch with clay(%) ≥ 0.5*silt(%) + 8 in at least one sample. A range of secondary minerals, which frequently includes interstratified minerals and indicates high local variability in leaching conditions, is also commonly present in regoliths exposed to periglacial conditions during their formation. Clay/silt ratios display a threshold response to temperature, related to the freezing point of water, but there is little response to precipitation or regolith residence time. Lithology controls clay and silt abundances, which increase from felsic, through intermediate, to mafic compositions, but does not control clay/silt ratios. Use of a sedigraph or Coulter Counter to determine regolith granulometry systematically indicates lower clay abundances and intra-site variability than use of a pipette or hydrometer. In contrast to clay/silt ratios, secondary mineral assemblages vary according to regolith residence time, temperature, and/or precipitation. A microsystems model is invoked as a conceptual framework in which to interpret the concurrent formation of the observed secondary mineral ranges. According to the fingerprint of chemical weathering in periglacial landscapes, there is generally no evidence of blockfield origins under warm Neogene climates. Nearly all blockfields appear to be a product of Quaternary physical and chemical weathering. A more dominant role for periglacial processes in further bevelling elevated, low relief, non-glacial surface remnants in otherwise glacially eroded landscapes is therefore indicated.

Impact of clay mineral on air oxidation of PAH-contaminated soils.

PubMed

Biache, Coralie; Kouadio, Olivier; Lorgeoux, Catherine; Faure, Pierre

2014-09-01

This work investigated the impact of a clay mineral (bentonite) on the air oxidation of the solvent extractable organic matters (EOMs) and the PAHs from contaminated soils. EOMs were isolated from two coking plant soils and mixed with silica sand or bentonite. These samples, as well as raw soils and bentonite/soil mixtures, were oxidized in air at 60 and 100 °C for 160 days. Mineralization was followed by measuring the CO2 produced over the experiments. EOM, polycyclic aromatic compound (PAC), including PAH, contents were also determined. Oxidation led to a decrease in EOM contents and PAH concentrations, these diminutions were enhanced by the presence of bentonite. Transfer of carbon from EOM to insoluble organic matter pointed out a condensation phenomenon leading to a stabilization of the contamination. Higher mineralization rates, observed during the oxidation of the soil/bentonite mixtures, seem to indicate that this clay mineral had a positive influence on the transformation of PAC into CO2.

An Evidence-Based Review on Medicinal Value of Clays in Traditional Persian Medicine.

PubMed

Hosseinkhani, Ayda; Montaseri, Hashem; Hosamo, Ammar; Zarshenas, Mohammad Mehdi

2017-01-01

The use of earths and clays for medical purposes dates back to antiquity. In recent years, there has been an increasing interest in researches on traditional remedies in the hope of discovering new drug. Iran is an ancient country with a medical backbone acquired from the experiences of ancient Persian scholars, who had made a great contribution to the development of the medical sciences. Many medical and pharmaceutical books by early Persian scientists still exist and may have the potential of leading researchers to new drug discoveries. Owing to the emergence of new and antimicrobial-resistant infections, present-day medicine has recently begun focusing on medicinal earths and clays especially as mineral antimicrobials. The current study is, therefore, aimed at gathering information regarding medicinal clays in traditional Persian medicine (TPM). Five main Persian materia medica with the key word 'tin' (clay) and current databases such as PubMed, Scopus, ScienceDirect, and Google Scholar were searched by key words 'white, green, red, maroon, violet, black, grey and pink clays' and 'pharmacological effects'. Twenty three clays were found in Persian manuscripts. Although their mineralogical compositions are unknown, different pharmacological properties have been attributed to these mineral medicaments. Clay's properties were widely used in medieval times for the treatment of infections to poisoning. They were also used in compound formulations, possibly for their pharmaceutical formulation modifying effects. Modern scientific proofs have also been found in many of the medicinal clays reported in Persian manuscripts. Although many of the reported clays are still unknown, their characterization may lead to new medicinal developments. Novel analytical methods available today make it possible to elucidate the chemical compositions of these minerals as parameters responsible for their medicinal effects. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Formation and Coloring Mechanism of Typical Aluminosilicate Clay Minerals for CoAl2O4 Hybrid Pigment Preparation

PubMed Central

Zhang, Anjie; Mu, Bin; Wang, Xiaowen; Wen, Lixin; Wang, Aiqin

2018-01-01

Different kinds of aluminosilicate minerals were employed to fabricate CoAl2O4 hybrid pigment for studying its formation and coloring mechanism. It revealed that the color of the obtained hybrid pigments was determined by the content of Al2O3 and lightness of clay minerals. The higher the Al2O3 content and the lightness of clay minerals, the better the color parameters of hybrid pigments. During the preparation of hybrid pigments, CoAl2O4 nanoparticles were confined to be loaded on the surface of the aluminosilicate minerals, which effectively prevented from the aggregation and the size increase of CoAl2O4 nanoparticles. What's more, aluminosilicate mineral might be an ideal natural aluminum source to compensate the aluminum loss due to the dissolution of Al(OH)3 at alkaline medium during precursor preparation, keeping an optimum molar ratio of Co2+/Al3+ for formation of spinel CoAl2O4 pigments in the process of high-temperature crystallization. PMID:29725589

Formation and Coloring Mechanism of Typical Aluminosilicate Clay Minerals for CoAl2O4 Hybrid Pigment Preparation.

PubMed

Zhang, Anjie; Mu, Bin; Wang, Xiaowen; Wen, Lixin; Wang, Aiqin

2018-01-01

Different kinds of aluminosilicate minerals were employed to fabricate CoAl 2 O 4 hybrid pigment for studying its formation and coloring mechanism. It revealed that the color of the obtained hybrid pigments was determined by the content of Al 2 O 3 and lightness of clay minerals. The higher the Al 2 O 3 content and the lightness of clay minerals, the better the color parameters of hybrid pigments. During the preparation of hybrid pigments, CoAl 2 O 4 nanoparticles were confined to be loaded on the surface of the aluminosilicate minerals, which effectively prevented from the aggregation and the size increase of CoAl 2 O 4 nanoparticles. What's more, aluminosilicate mineral might be an ideal natural aluminum source to compensate the aluminum loss due to the dissolution of Al(OH) 3 at alkaline medium during precursor preparation, keeping an optimum molar ratio of Co 2+ /Al 3+ for formation of spinel CoAl 2 O 4 pigments in the process of high-temperature crystallization.

Heteroaggregation of Silver Nanoparticles with Clay Minerals in Aqueous System

NASA Astrophysics Data System (ADS)

Liu, J.; Burrow, E.; Hwang, Y.; Lenhart, J.

2013-12-01

Nanoparticles are increasingly being used in industrial processes and consumer products that exploit their beneficial properties and improve our daily lives. Nevertheless, they also attract attention when released into natural environment due to their potential for causing adverse effects. The fate and transport of nanoparticles in aqueous systems have been the focus of intense study. However, their interactions with other natural particles have received only limited attention. Clay minerals are ubiquitous in most aquatic systems and their variably charged surfaces can act as deposition sites that can alter the fate and transport of nanoparticles in natural aqueous environments. In this study, we investigated the homoaggregation of silver nanoparticles with different coating layers and their heteroaggregation behavior with clay minerals (illite, kaolinite, montmorillonite) in neutral pH solutions. Silver nanoparticles with a nominal diameter of 80 nm were synthesized with three different surface coating layers: uncoated, citrate-coated and Tween-coated. Illite (IMt-2), kaolinite (KGa-2), and montmorillonite (SWy-2) were purchased from the Clay Mineral Society (Indiana) and pretreated to obtain monocationic (Na-clay) and dicationic (Ca-clay) suspensions before the experiments. The change in hydrodynamic diameter as a function of time was monitored using dynamic light scattering (DLS) measurements in order to evaluate early stage aggregation as a function of electrolyte concentration in both the homo- and heteroaggregation scenarios. A shift in the critical coagulation concentration (CCC) values to lower electrolyte concentrations was observed in binary systems, compared to single silver nanoparticle and clay systems. The results also suggest more rapid aggregation in binary system during the early aggregation stage when compared to the single-particle systems. The behavior of citrate-coated silver nanoparticles was similar to that of the bare particles, while the Tween-coated silver nanoparticles showed high stability in both single and binary systems. There were no significant differences in early stage aggregation kinetics observed inthe Na-clay-nanoparticle or Ca-clay-nanoparticle systems, which suggested that the CCC values of the single Na- or Ca-clay suspensions depend only on the electrolyte concentration, not the original cations on the clay surface. These results provide a basic idea for understanding the heteroaggregation of different silver nanoparticles and clays, which can be utilized in further study of fate and transport of engineered nanoparticles in natural aqueous system.

Geology and Refractory Clay Deposits of the Haldeman and Wrigley Quadrangles, Kentucky

USGS Publications Warehouse

Patterson, Sam H.; Hosterman, John W.; Huddle, John Warfield

1962-01-01

The Haldeman and Wrigley 7th-minute quadrangles are near the western edge of the eastern Kentucky coal field and cover an area of approximately 117 square miles in parts of Carter, Rowan, Elliott, and Morgan Counties, Ky. The rocks exposed in the two quadrangles are of Early and Late Mississippian and Early and Middle Pennsylvanian age. The Mississippian rocks are composed of the thick Brodhead formation, which consists of siltstone and shale, and eleven thin marine limestone and shale formations, having an aggregate thickness of about 150 feet. The Lee and Breathitt formations, of Pennsylvanian age, consist of sandstone, siltstone, and shale; they also contain thin beds of coal and several beds of underclay, including the economically important Olive Hill clay bed of Crider, 1913. Pennsylvanian rocks include beds of both continental and marine origin. The eleven thin Mississippian formations and the upper-most part of the thick Brodhead formation are truncated by a prominent unconformity on which rocks of Pennsylvanian age rest. The rocks occupy a region of gentle dips between the Cincinnati arch and the Appalachian Mountains. Refractory clay deposits are in the Olive Hill clay bed, which occurs in the lower part of the Lee formation. The Olive Hill clay bed is discontinuous and consists of a series of irregularly shaped lenses. The bed is approximately two-thirds semifiint clay and one-third flint clay, and it contains minor amounts of plastic clay. Some of the flint clay is nearly pure kaolinite, but the semi flint and plastic clay consists of mixtures of kaolinite, illite, and mixed-layer clay minerals. The structure of the kaolinite ranges from highly crystalline to very poorly crystalline 'fireclay' type. The degree of crystallinity of the kaolinite and the hardness of the clay vary inversely with the amount of illite and mixed-layer clay minerals present. The nearly pure kaolinite is believed to have formed by the removal of alkalies and some silica fram mixtures of kaolinite, illite, and mixed-layer clays by leaching in swamps to the deposition of the beds overlying the clay. The refractory properties of the clay vary directly with the purity of the kaolinite, and refractoriness decreases as the proportions of illite and mixed-layer clays increase. Certain nonclay minerals, chiefly siderite, pyrite, and iron oxide-bearing minerals, also act as fiuxes, reducing the refractory properties of the clay. The entire resources of clay in the Olive Hill clay bed are roughly and tentatively estimated to include 105,000,000 tons in the Haldeman quadrangle and 175,000,000 tons in the Wrigley quadrangle. Much of this clay is of poor quality and the amount that is better than the minimum requirements for use in refractories is probably about 30,000,000 tons. Only a fraction of this tonnage is suitable for superheat-duty products. Limestone is the only nonmetallic mineral resource other than refractory clay that has been developed in the two quadrangles, but 1arge amounts of shale suitable for use in making lightweight aggregate and structural clay products may also be present. Most of the limestone, which is quarried. in both quadrangles, is used for road-metal, concrete aggregate, and agriculture stone, but some of the limestone is of the quality that would be suitable for other uses. Virtually all the Mississippian Beech Creek limestone of Malott, 1919 which is as much as 18 feet thick, consists of high-calcium limestone. Shale beds that appear most favoralble for making lightweight aggregate are in the shale facies of the Lee formation of Pennsylvanian age. Shale that is probably suitable for structural clay products is present in the shale flacles of the Lee formation and in the Muldraugh formation of Mississippian age. Several dry holes have been drilled in search for oil and gas within the area of the two quadrangles. Though no commercial production was ever attained, one well furnished a supply of gas f

Decomposition of algal lipids in clay-enriched marine sediment under oxic and anoxic conditions

NASA Astrophysics Data System (ADS)

Lü, Dongwei; Song, Qian; Wang, Xuchen

2010-01-01

A series of laboratory incubation experiments were conducted to examine the decomposition of algal organic matter in clay-enriched marine sediment under oxic and anoxic conditions. During the 245-day incubation period, changes in the concentrations of TOC, major algal fatty acid components (14:0, 16:0, 16:1, 18:1 and 20:5), and n-alkanes (C16-C23) were quantified in the samples. Our results indicate that the organic matters were degraded more rapidly in oxic than anoxic conditions. Adsorption of fatty acids onto clay minerals was a rapid and reversible process. Using a simple G model, we calculated the decomposition rate constants for TOC, n-alkanes and fatty acids which ranged from 0.017-0.024 d-1, 0.049-0.103 d-1 and 0.011 to 0.069 d-1, respectively. Algal organic matter degraded in two stages characterized by a fast and a slow degradation processes. The addition of clay minerals montmorillonite and kaolinite to the sediments showed significant influence affecting the decomposition processes of algal TOC and fatty acids by adsorption and incorporation of the compounds with clay particles. Adsorption/association of fatty acids by clay minerals was rapid but appeared to be a slow reversible process. In addition to the sediment redox and clay influence, the structure of the compounds also played important roles in affecting their degradation dynamic in sediments.

Selenium isotope fractionation during adsorption onto the modified clay minerals

NASA Astrophysics Data System (ADS)

Xu, W.; Jianming, Z.; Tan, D.; Qin, H.

2016-12-01

Currently, Selenium (Se) isotopes have been used as a paleoenvironmental proxy to trace Se evolution in Ancient Ocean. And many researchers considered the variation of Se isotopes in nature mainly result from the reduction of Se oxyanion, while Se isotope fractionation during adsorption onto minerals was rarely reported. Therefore, based on the previous studies [1, 2], we used three common clay minerals in supergene environment: montmorillonite, illite and kaolinite as an adsorbent to study Se isotope fractionation during adsorption. Before doing adsorption experiments, the adsorbent were modified as Na-clay minerals to remove the possibility of interference of Ca2+, Fe3+, Fe2+ as well as organic matters. A batch adsorption experiments were carried out at room temperature (23 ±2 °) under N2 atmosphere, initial Se concentration (SeO32-/ SeO42-) was respectively 200ng and 100ng, the solution ionic strength was 0.1mol/L NaCl; the ratio of liquid to solid is 2g / L, and pH = 5. Experimental results showed that adsorption reached a steady state during 48h, and the maximum adsorption for SeO32- was larger than SeO42-. The isotope data showed that SeO42- adsorbed onto three clay minerals didn't present obvious Se isotope fractionation, generally δ82/78Se is less than 0.1 ‰. Meanwhile, SeO32- during adsorption process also didn't show the significant fractionation, less than 0.3 ‰. However, interestingly, for SeO32- the δ82/78Se values of solution during adsorption onto kaolinite underwent a process of increasing by 0.5‰ compared to the initial solution and then decreasing to 0.3‰. We speculated the reason may not be related to the surface charge of the clay minerals, but mostly with the layered structure of clay minerals. Montmorillonite and illite are 2: 1; kaolinite is 1: 1 layered structure. The different layered structure may influence the isotope fraction between Se oxyanions and clay minerals. These still needs further and more experiments to definitely explain this phenomenon. This work was financially supported by National Key Basic Research Program of China (2014CB238903) and Natural Science Foundation of China (41473028, 41273029). [1] D. Peak et al. Soil Science Society of America Journal. 2006, 192-203. [2] T. Missana et al. Journal of Colloid and Interface Science. 2009, 334, 132-138.

Clay minerals related to the circulation of geothermal fluids in boreholes at Rittershoffen (Alsace, France)

NASA Astrophysics Data System (ADS)

Vidal, Jeanne; Patrier, Patricia; Genter, Albert; Beaufort, Daniel; Dezayes, Chrystel; Glaas, Carole; Lerouge, Catherine; Sanjuan, Bernard

2018-01-01

Two geothermal wells, GRT-1 and GRT-2, were drilled into the granite at Rittershoffen (Alsace, France) in the Upper Rhine Graben to exploit geothermal resources at the sediment-basement interface. Brine circulation occurs in a permeable fracture network and leads to hydrothermal alteration of the host rocks. The goal of the study was to characterize the petrography and mineralogy of the altered rocks with respect to the permeable fracture zones in the granitic basement. As clay minerals are highly reactive to hydrothermal alteration, they can be used as indicators of present-day and paleo-circulation systems. Special attention has been paid to the textural, structural and chemical properties of these minerals. The fine-grained clay fraction (< 5 μm) was analyzed around the originally permeable fracture zones to observe the crystal structure of clay minerals using X-ray diffraction. Chemical microanalysis of the clay minerals was performed using scanning electron microscopy coupled with energy dispersive X-ray spectroscopy. The occurrences of mixed layers illite-smectite ( 10% smectite) provide a promising guide for identifying the fracture zones that control the present-day circulation of geothermal fluids in the Rittershoffen wells. However, multistage paleo-circulation systems could lead to an abundance of heterogeneous and fine-grained illitic minerals that could plug the fracture system. The permeability of fracture zones in the GRT-1 well was likely reduced because of an intense illitization, and the well was stimulated. The occurrence of chlorite in the permeable fracture zones of GRT-2 is indicative of less intense illitization, and the natural permeability is much higher in GRT-2 than in GRT-1.

The role of reaction affinity and secondary minerals in regulating chemical weathering rates at the Santa Cruz Soil Chronosequence, California

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maher, K.; Steefel, C. I.; White, A.F.

2009-02-25

In order to explore the reasons for the apparent discrepancy between laboratory and field weathering rates and to determine the extent to which weathering rates are controlled by the approach to thermodynamic equilibrium, secondary mineral precipitation and flow rates, a multicomponent reactive transport model (CrunchFlow) was used to interpret soil profile development and mineral precipitation and dissolution rates at the 226 ka marine terrace chronosequence near Santa Cruz, CA. Aqueous compositions, fluid chemistry, transport, and mineral abundances are well characterized (White et al., 2008, GCA) and were used to constrain the reaction rates for the weathering and precipitating minerals inmore » the reactive transport modeling. When primary mineral weathering rates are calculated with either of two experimentally determined rate constants, the nonlinear, parallel rate law formulation of Hellmann and Tisser and [2006] or the aluminum inhibition model proposed by Oelkers et al. [1994], modeling results are consistent with field-scale observations when independently constrained clay precipitation rates are accounted for. Experimental and field rates, therefore, can be reconciled at the Santa Cruz site. Observed maximum clay abundances in the argillic horizons occur at the depth and time where the reaction fronts of the primary minerals overlap. The modeling indicates that the argillic horizon at Santa Cruz can be explained almost entirely by weathering of primary minerals and in situ clay precipitation accompanied by undersaturation of kaolinite at the top of the profile. The rate constant for kaolinite precipitation was also determined based on model simulations of mineral abundances and dissolved Al, SiO{sub 2}(aq) and pH in pore waters. Changes in the rate of kaolinite precipitation or the flow rate do not affect the gradient of the primary mineral weathering profiles, but instead control the rate of propagation of the primary mineral weathering fronts and thus total mass removed from the weathering profile. Our analysis suggests that secondary clay precipitation is as important as aqueous transport in governing the amount of dissolution that occurs within a profile because clay minerals exert a strong control over the reaction affinity of the dissolving primary minerals. The modeling also indicates that the weathering advance rate and the total mass of mineral dissolved is controlled by the thermodynamic saturation of the primary dissolving phases plagioclase and K-feldspar, as is evident from the difference in propagation rates of the reaction fronts for the two minerals despite their very similar kinetic rate laws.« less

Uranium mineralization in fluorine-enriched volcanic rocks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burt, D.M.; Sheridan, M.F.; Bikun, J.

1980-09-01

Several uranium and other lithophile element deposits are located within or adjacent to small middle to late Cenozoic, fluorine-rich rhyolitic dome complexes. Examples studied include Spor Mountain, Utah (Be-U-F), the Honeycomb Hills, Utah (Be-U), the Wah Wah Mountains, Utah (U-F), and the Black Range-Sierra Cuchillo, New Mexico (Sn-Be-W-F). The formation of these and similar deposits begins with the emplacement of a rhyolitic magma, enriched in lithophile metals and complexing fluorine, that rises to a shallow crustal level, where its roof zone may become further enriched in volatiles and the ore elements. During initial explosive volcanic activity, aprons of lithicrich tuffsmore » are erupted around the vents. These early pyroclastic deposits commonly host the mineralization, due to their initial enrichment in the lithophile elements, their permeability, and the reactivity of their foreign lithic inclusions (particularly carbonate rocks). The pyroclastics are capped and preserved by thick topaz rhyolite domes and flows that can serve as a source of heat and of additional quantities of ore elements. Devitrification, vapor-phase crystallization, or fumarolic alteration may free the ore elements from the glassy matrix and place them in a form readily leached by percolating meteoric waters. Heat from the rhyolitic sheets drives such waters through the system, generally into and up the vents and out through the early tuffs. Secondary alteration zones (K-feldspar, sericite, silica, clays, fluorite, carbonate, and zeolites) and economic mineral concentrations may form in response to this low temperature (less than 200 C) circulation. After cooling, meteoric water continues to migrate through the system, modifying the distribution and concentration of the ore elements (especially uranium).« less

Modeling cation/anion-water interactions in functional aluminosilicate structures.

PubMed

Richards, A J; Barnes, P; Collins, D R; Christodoulos, F; Clark, S M

1995-02-01

A need for the computer simulation of hydration/dehydration processes in functional aluminosilicate structures has been noted. Full and realistic simulations of these systems can be somewhat ambitious and require the aid of interactive computer graphics to identify key structural/chemical units, both in the devising of suitable water-ion simulation potentials and in the analysis of hydrogen-bonding schemes in the subsequent simulation studies. In this article, the former is demonstrated by the assembling of a range of essential water-ion potentials. These span the range of formal charges from +4e to -2e, and are evaluated in the context of three types of structure: a porous zeolite, calcium silicate cement, and layered clay. As an example of the latter, the computer graphics output from Monte Carlo computer simulation studies of hydration/dehydration in calcium-zeolite A is presented.

Efficient removal of cesium from low-level radioactive liquid waste using natural and impregnated zeolite minerals.

PubMed

Borai, E H; Harjula, R; Malinen, Leena; Paajanen, Airi

2009-12-15

The objective of the proposed work was focused to provide promising solid-phase materials that combine relatively inexpensive and high removal capacity of some radionuclides from low-level radioactive liquid waste (LLRLW). Four various zeolite minerals including natural clinoptilolite (NaNCl), natural chabazite (NaNCh), natural mordenite (NaNM) and synthetic mordenite (NaSM) were investigated. The effective key parameters on the sorption behavior of cesium (Cs-134) were investigated using batch equilibrium technique with respect to the waste solution pH, contacting time, potassium ion concentration, waste solution volume/sorbent weight ratio and Cs ion concentration. The obtained results revealed that natural chabazite (NaNCh) has the higher distribution coefficients and capacity towards Cs ion rather than the other investigated zeolite materials. Furthermore, novel impregnated zeolite material (ISM) was prepared by loading Calix [4] arene bis(-2,3 naphtho-crown-6) onto synthetic mordenite to combine the high removal uptake of the mordenite with the high selectivity of Calix [4] arene towards Cs radionuclide. Comparing the obtained results for both NaSM and the impregnated synthetic mordenite (ISM-25), it could be observed that the impregnation process leads to high improvement in the distribution coefficients of Cs+ ion (from 0.52 to 27.63 L/g). The final objective in all cases was aimed at determining feasible and economically reliable solution to the management of LLRLW specifically for the problems related to the low decontamination factor and the effective recovery of monovalent cesium ion.

21 CFR 186.1256 - Clay (kaolin).

Code of Federal Regulations, 2012 CFR

2012-04-01

... CONSUMPTION (CONTINUED) INDIRECT FOOD SUBSTANCES AFFIRMED AS GENERALLY RECOGNIZED AS SAFE Listing of Specific...-58-7) consists of hydrated aluminum silicate. The commercial products of clay (kaolin) contain... kaolin. Kaolinite or china clay is whiter, less contaminated with extraneous minerals, and less plastic...

21 CFR 186.1256 - Clay (kaolin).

Code of Federal Regulations, 2011 CFR

2011-04-01

... CONSUMPTION (CONTINUED) INDIRECT FOOD SUBSTANCES AFFIRMED AS GENERALLY RECOGNIZED AS SAFE Listing of Specific...-58-7) consists of hydrated aluminum silicate. The commercial products of clay (kaolin) contain... kaolin. Kaolinite or china clay is whiter, less contaminated with extraneous minerals, and less plastic...

21 CFR 186.1256 - Clay (kaolin).

Code of Federal Regulations, 2013 CFR

2013-04-01

... CONSUMPTION (CONTINUED) INDIRECT FOOD SUBSTANCES AFFIRMED AS GENERALLY RECOGNIZED AS SAFE Listing of Specific...-58-7) consists of hydrated aluminum silicate. The commercial products of clay (kaolin) contain... kaolin. Kaolinite or china clay is whiter, less contaminated with extraneous minerals, and less plastic...

21 CFR 186.1256 - Clay (kaolin).

Code of Federal Regulations, 2010 CFR

2010-04-01

... CONSUMPTION (CONTINUED) INDIRECT FOOD SUBSTANCES AFFIRMED AS GENERALLY RECOGNIZED AS SAFE Listing of Specific...-58-7) consists of hydrated aluminum silicate. The commercial products of clay (kaolin) contain... kaolin. Kaolinite or china clay is whiter, less contaminated with extraneous minerals, and less plastic...

Removal of cyanobacterial blooms in Taihu Lake using local soils. I. Equilibrium and kinetic screening on the flocculation of Microcystis aeruginosa using commercially available clays and minerals.

PubMed

Pan, Gang; Zhang, Ming-Ming; Chen, Hao; Zou, Hua; Yan, Hai

2006-05-01

Algal removal abilities of 26 clays/minerals were classified into three categories according to the 8-h equilibrium removal efficiency (Q8h) and removal rate at a clay loading of 0.7 g/L. Type I clays (sepiolite, talc, ferric oxide, and kaolinite) had a Q8h > 90%, a t50 (time needed to remove 50% of the algae) < 15 min, and a t80 < 2.5 h. Type II clays (6 clays) had a Q8h 50-90%, a t50 < 2.5 h, and a t80 > 2.5 h. Type III clays (14 clays) with Q8h < 50%, t50 > 8 h and t80 > 14 h had no practical value in removal of algal blooms. When the clay loading was reduced to 0.2 g/L, Q8h for all the 25 materials decreased to below 60%, except for sepiolite whose Q8h remained about 97%. The high efficiency for sepiolite to flocculate M. aeruginosa cells in freshwaters was due to the mechanism of netting and bridging effect.

Cracking vegetable oil from Callophylluminnophyllum L. seeds to bio-gasoline by Ni-Mo/Al2O3 and Ni-Mo/Zeolite as micro-porous catalysts

NASA Astrophysics Data System (ADS)

Savitri, Effendi, R.; Tursiloadi, S.

2016-02-01

Natural minerals such as zeolite are local natural resources in the various regions in Indonesia. Studies on the application of natural mineral currently carried out by national research institutions, among others, as a filler, bleaching agent, or dehydration agent. However, not many studies that utilize these natural minerals as green catalysts material which has high performance for biomass conversion processes and ready to be applied directly by the bio-fuel industry. The trend movement of green and sustainable chemistry research that designing environmentally friendly chemical processes from renewable raw materials to produce innovative products derived biomass for bio-fuel. Callophylluminnophyllum L. seeds can be used as raw material for bio-energy because of its high oil content. Fatty acid and triglyceride compounds from this oil can be cracked into bio-gasoline, which does not contain oxygen in the hydrocarbon structure. Bio-gasoline commonly is referred to as drop-in biofuel because it can be directly used as a substitute fuel. This paper focused on the preparation and formulation of the catalyst NiMo/H-Zeolite and Ni-Mo/Al2O3 which were used in hydro-cracking process of oil from Callophylluminnophyllum L. seeds to produce bio-gasoline. The catalysts were analyzed using XRD, BET and IR-adsorbed pyridine method. The results of hydro-cracking products mostly were paraffin (C10-C19) straight chain, with 59.5 % peak area based on GC-MS analysis.

Mineral Resources of the Warm Springs Wilderness Study Area, Mohave County, Arizona

USGS Publications Warehouse

Gray, Floyd; Jachens, Robert C.; Miller, Robert J.; Turner, Robert L.; Knepper, Daniel H.; Pitkin, James A.; Keith, William J.; Mariano, John; Jones, Stephanie L.; Korzeb, Stanley L.

1986-01-01

At the request of the U.S. Bureau of Land Management, approximately 113,500 acres of the Warm Springs Wilderness Study Area (AZ-020-028/029) were evaluated for mineral resources and mineral resource potential. In this report, the area studied is referred to as the 'wilderness study area' or 'study area'; any reference to the Warm Springs Wilderness Study Area refers only to that part of the wilderness study area for which a mineral survey was requested. This study area is located in west-central Arizona. The U.S. Geological Survey and the U.S. Bureau of Mines conducted geological, geochemical, and geophysical surveys to appraise the identified mineral resources (known) and assess the mineral resource potential (undiscovered) of the study area. fieldwork for this report was carried out largely in 1986-1989. There is a 1-million short ton indicated subeconomic resource of clinoptilolite-mordenite zeolite and an additional inferred resource of 2 million short tons near McHeffy Butte, approximately 2 miles west of the study area. A perlite deposit in the southeast corner of the study area contains an inferred subeconomic resource totaling 13 million short tons. An inferred subeconomic resource of gold in 225 short tons of quartz having a grade of 0.01 8 troy ounces per short ton is present at the Cook mine, 0.5 miles west of the study area. The northwestern part of the Warm Springs Wilderness Study Area has high mineral resource potential for gold and silver. The south-central part of the study area has one area of moderate and one area north of this south-central part has low mineral resource potential for gold and silver in and near Warm Springs Canyon; the mineral resource potential for gold is also moderate in three small areas in the southern part and one area in the northeastern part of the study area. The mineral resource potential for zeolite is high for the area surrounding the McHeffy Butte prospect and for one area in the southern part of the study area. Two areas inside the south and southeast boundaries of the study area have high mineral resource potential for perlite. The potential for ka: olinite resources is moderate in two areas in the southern part of the study area. The southern part of the study area has low resource potential for perlite and zeolite. Geothermal energy resource potential of the study area is low. The study area has no resource potential for oil and gas.

Pore structure characterization of Chang-7 tight sandstone using MICP combined with N2GA techniques and its geological control factors

NASA Astrophysics Data System (ADS)

Cao, Zhe; Liu, Guangdi; Zhan, Hongbin; Li, Chaozheng; You, Yuan; Yang, Chengyu; Jiang, Hang

2016-11-01

Understanding the pore networks of unconventional tight reservoirs such as tight sandstones and shales is crucial for extracting oil/gas from such reservoirs. Mercury injection capillary pressure (MICP) and N2 gas adsorption (N2GA) are performed to evaluate pore structure of Chang-7 tight sandstone. Thin section observation, scanning electron microscope, grain size analysis, mineral composition analysis, and porosity measurement are applied to investigate geological control factors of pore structure. Grain size is positively correlated with detrital mineral content and grain size standard deviation while negatively related to clay content. Detrital mineral content and grain size are positively correlated with porosity, pore throat radius and withdrawal efficiency and negatively related to capillary pressure and pore-to-throat size ratio; while interstitial material is negatively correlated with above mentioned factors. Well sorted sediments with high debris usually possess strong compaction resistance to preserve original pores. Although many inter-crystalline pores are produced in clay minerals, this type of pores is not the most important contributor to porosity. Besides this, pore shape determined by N2GA hysteresis loop is consistent with SEM observation on clay inter-crystalline pores while BJH pore volume is positively related with clay content, suggesting N2GA is suitable for describing clay inter-crystalline pores in tight sandstones.

Pore structure characterization of Chang-7 tight sandstone using MICP combined with N2GA techniques and its geological control factors

PubMed Central

Cao, Zhe; Liu, Guangdi; Zhan, Hongbin; Li, Chaozheng; You, Yuan; Yang, Chengyu; Jiang, Hang

2016-01-01

Understanding the pore networks of unconventional tight reservoirs such as tight sandstones and shales is crucial for extracting oil/gas from such reservoirs. Mercury injection capillary pressure (MICP) and N2 gas adsorption (N2GA) are performed to evaluate pore structure of Chang-7 tight sandstone. Thin section observation, scanning electron microscope, grain size analysis, mineral composition analysis, and porosity measurement are applied to investigate geological control factors of pore structure. Grain size is positively correlated with detrital mineral content and grain size standard deviation while negatively related to clay content. Detrital mineral content and grain size are positively correlated with porosity, pore throat radius and withdrawal efficiency and negatively related to capillary pressure and pore-to-throat size ratio; while interstitial material is negatively correlated with above mentioned factors. Well sorted sediments with high debris usually possess strong compaction resistance to preserve original pores. Although many inter-crystalline pores are produced in clay minerals, this type of pores is not the most important contributor to porosity. Besides this, pore shape determined by N2GA hysteresis loop is consistent with SEM observation on clay inter-crystalline pores while BJH pore volume is positively related with clay content, suggesting N2GA is suitable for describing clay inter-crystalline pores in tight sandstones. PMID:27830731

Studies of the water adsorption on Lampung’s natural zeolite of Indonesia for cooling application

NASA Astrophysics Data System (ADS)

Wulandari, D. A.; Nasruddin; Lemington

2018-03-01

Part of minerals that originally formed from volcanic rock and ash layers reacting further with alkaline groundwater is called natural zeolite, where its sources are not always available in all countries. Indonesia is located in the ring of fire which have a huge sources of zeolite, one of the area is Lampung, South Sumatra. Natural zeolite has been considered as one of potential heat adsorbent medium which can contribute to the energy consumption and reduce air pollution in the using of cooling application. The characteristic of this Lampung natural zeolite such as adsorption kinetics, adsorption water uptake, and adsorption capacity were test with ASAP 2020 system. Sorption kinetics by this experiment of zeolite samples were carried out in a constant temperature and humidity chamber. The chamber can supply constant air condition with deviations of ±0.5 °C for temperature and ±3% for relative humidity. The data based on rate of adsorption and the defined working condition was set as 20°C and 70% RH. Pore volume is a significant parameter for determining the limitation of water uptake, which can describe the saturated condition of zeolite. Sorption isotherm models used to describe sorption phenomena are commonly deduced from the Polanyi potential theory were investigated. The water adsorption quantity increased with the increase of relative pressure. To sum up, this pure zeolite has a less heat and mass transfer performance so its need to be activated before using in cooling application to get their great potential and by being coated in a desiccant heat exchanger systems.

Tracking Hydrothermal Fluid Pathways from Surface Alteration Mineralogy: The Case of Licancura Geothermal Field, Northern Chile

NASA Astrophysics Data System (ADS)

Camus, E.; Elizalde, J. D.; Morata, D.; Wechsler, C.

2017-12-01

In geothermal systems alteration minerals are evidence of hot fluid flow, being present even in absence of other surface manifestations. Because these minerals result from the interaction between geothermal fluids and surrounding host rocks, they will provide information about features of thermal fluids as temperature, composition and pH, allowing tracking their changes and evolution. In this work, we study the Licancura Geothermal field located in the Andean Cordillera in Northern Chile. The combination of Principal Components Analysis on ASTER-L1T imagery and X Ray Diffraction (XRD) allow us to interpret fluid conditions and the areas where fluid flow took place. Results from red, green, blue color composite imagery show the presence of three types of secondary paragenesis. The first one corresponds to hematite and goethite, mainly at the east of the area, in the zone of eroded Pliocene volcanic edifices. The second one, mainly at the center of the area, highlighting propylitic alteration, includes minerals such as chlorite, illite, calcite, zeolites, and epidote. The third paragenesis, spatially related to the intersection between faults, represents advanced argillic alteration, includes minerals as alunite, kaolinite, and jarosite. XRD analysis support results from remote sensing techniques. These results suggest an acid pH hydrothermal fluid reaching temperatures at surface up to 80-100°C, which used faults as a conduit, originating advanced argillic minerals. The same fluid was, probably, responsible for propylitic paragenesis. However, iron oxides paragenesis identified in the area of eroded volcanoes probably corresponds to other processes associated with weathering rather than geothermal activity. In this work, we propose the applicability of remote sensing techniques as a first level exploration tool useful for high-altitude geothermal fields. Detailed clay mineral studies (XRD and SEM) would allow us to a better characterization of the geothermal fluid flow and the defining fluid pathways in the Licancura geothermal field. This work is a contribution to the FONDAP-CONICYT 15090013 Project. E.C. thanks CONICYT for her Ph.D. grant.

Effect of minerals on accumulation of Cs by fungus Saccaromyces cerevisiae.

PubMed

Ohnuki, Toshihiko; Sakamoto, Fuminori; Yamasaki, Shinya; Kozai, Naofumi; Shiotsu, Hiroyuki; Utsunomiya, Satoshi; Watanabe, Naoko; Kozaki, Tamotsu

2015-06-01

The accumulation of Cs by unicellular fungus of Saccharomyces cerevisiae in the presence of minerals has been studied to elucidate the role of microorganisms in the migration of radioactive Cs in the environment. Two different types of experiments were employed: experiments using stable Cs to examine the effect of a carbon source on the accumulation of Cs, and accumulation experiments of radioactive Cs from agar medium containing (137)Cs and zeolite, vermiculite, phlogopite, smectite, mica, or illite as mineral supplements. In the former type of experiments, the Cs-accumulated cells were analyzed by scanning electron microscopy equipped with energy dispersive X-ray analysis (SEM-EDS). In the latter type, the radioactivity in the yeast cells was measured by an autoradiography technique. When a carbon source was present, higher amounts of Cs accumulated in the cells than in the resting condition without a carbon source. Analyses with SEM-EDS showed that no mineral formed on the cell surface. These results indicate that the yeast cells accumulate Cs by adsorption on the cell surface and intracellular accumulation. In the presence of minerals in the agar medium, the radioactivity in the yeast cells was in the order of mica > smectite, illite > vermiculite, phlogopite, zeolite. This order is inversely correlated to the ratio of the concentration of radioactive Cs between the minerals and the medium solution. These results strongly suggest that the yeast accumulates radioactive Cs competitively with minerals. Copyright © 2015 Elsevier Ltd. All rights reserved.

The origin and emergence of life under impact bombardment.

PubMed

Cockell, Charles S

2006-10-29

Craters formed by asteroids and comets offer a number of possibilities as sites for prebiotic chemistry, and they invite a literal application of Darwin's 'warm little pond'. Some of these attributes, such as prolonged circulation of heated water, are found in deep-ocean hydrothermal vent systems, previously proposed as sites for prebiotic chemistry. However, impact craters host important characteristics in a single location, which include the formation of diverse metal sulphides, clays and zeolites as secondary hydrothermal minerals (which can act as templates or catalysts for prebiotic syntheses), fracturing of rock during impact (creating a large surface area for reactions), the delivery of iron in the case of the impact of iron-containing meteorites (which might itself act as a substrate for prebiotic reactions), diverse impact energies resulting in different rates of hydrothermal cooling and thus organic syntheses, and the indiscriminate nature of impacts into every available lithology-generating large numbers of 'experiments' in the origin of life. Following the evolution of life, craters provide cryptoendolithic and chasmoendolithic habitats, particularly in non-sedimentary lithologies, where limited pore space would otherwise restrict colonization. In impact melt sheets, shattered, mixed rocks ultimately provided diverse geochemical gradients, which in present-day craters support the growth of microbial communities.

Networking and rheology of concentrated clay suspensions "matured" in mineral medicinal water.

PubMed

Aguzzi, Carola; Sánchez-Espejo, Rita; Cerezo, Pilar; Machado, José; Bonferoni, Cristina; Rossi, Silvia; Salcedo, Inmaculada; Viseras, César

2013-09-10

This work studied the influence of "maturation" conditions (time and agitation) on aggregation states, gel structure and rheological behaviour of a special kind of pharmaceutical semisolid products made of concentrated clay suspensions in mineral medicinal water. Maturation of the samples was carried out in distilled and sulphated mineral medicinal water, both in static conditions (without agitation) and with manual stirring once a week, during a maximum period of three months. At the measured pH interval (7.5-8.0), three-dimensional band-type networks resulting from face/face contacts were predominant in the laminar (disc-like) clay suspensions, whereas the fibrous (rod-like) particles formed micro-aggregates by van der Waals attractions. The high concentration of solids in the studied systems greatly determined their behaviour. Rod-like sepiolite particles tend to align the major axis in aggregates promoted by low shearing maturation, whereas aggregates of disc-like smectite particles did not have a preferential orientation and their complete swelling required long maturation time, being independent of stirring. Maturation of both kinds of suspensions resulted in improved rheological properties. Laminar clay suspensions became more structured with time, independently from static or dynamic maturation conditions, whereas for fibrous clay periodic agitation was also required. Rheological properties of the studied systems have been related to aggregation states and networking mechanisms, depending on the type of clay minerals constituents. Physical stability of the suspensions was not impaired by the specific composition of the Graena medicinal water. Copyright © 2013 Elsevier B.V. All rights reserved.

Zeolites on Mars: Possible environmental indicators in soils and sediments

NASA Technical Reports Server (NTRS)

Ming, D. W.; Gooding, J. L.

1988-01-01

Weathering products should serve as indicators of weathering environments and may provide the best evidence of the nature of climate change on Mars. No direct mineralogical measurements of Martian regolith were performed by the Viking missions, but the biology and X-ray fluorescence experiments provided some information on the physiochemical properties of Martian regolith. Most post-Viking studies of candidate weathering products have emphasized phyllosilicates and Fe-oxides; zeolites are potentially important, but overlooked, candidate Martian minerals. Zeolites would be important on Mars for three different reasons. First, they are major sinks of atmospheric gases and, per unit mass, are stronger and more efficient sorbents than are phyllosilicates. Secondly, they can be virtually unique sorbents and shelters for organic compounds and possible catalysts for organic-based reactions. Finally, their exchangeable ions are good indicators of the chemical properties of solutions with which they have communicated. Accordingly, the search for information on past compositions of the Martian atmosphere and hydrosphere should find zeolites to be rich repositories.

A Prebiotic Chemistry Experiment on the Adsorption of Nucleic Acids Bases onto a Natural Zeolite.

PubMed

Anizelli, Pedro R; Baú, João Paulo T; Gomes, Frederico P; da Costa, Antonio Carlos S; Carneiro, Cristine E A; Zaia, Cássia Thaïs B V; Zaia, Dimas A M

2015-09-01

There are currently few mechanisms that can explain how nucleic acid bases were synthesized, concentrated from dilute solutions, and/or protected against degradation by UV radiation or hydrolysis on the prebiotic Earth. A natural zeolite exhibited the potential to adsorb adenine, cytosine, thymine, and uracil over a range of pH, with greater adsorption of adenine and cytosine at acidic pH. Adsorption of all nucleic acid bases was decreased in artificial seawater compared to water, likely due to cation complexation. Furthermore, adsorption of adenine appeared to protect natural zeolite from thermal degradation. The C=O groups from thymine, cytosine and uracil appeared to assist the dissolution of the mineral while the NH2 group from adenine had no effect. As shown by FT-IR spectroscopy, adenine interacted with a natural zeolite through the NH2 group, and cytosine through the C=O group. A pseudo-second-order model best described the kinetics of adenine adsorption, which occurred faster in artificial seawaters.

Evaluation of Zeolite Permeable Treatment Wall for the Removal of Strontium-90 from Groundwater

NASA Astrophysics Data System (ADS)

Seneca, S. M.; Bronner, C.; Ross, E.; Rabideau, A. J.

2009-05-01

Experimental and modeling studies have been initiated to evaluate the potential performance of a permeable treatment wall comprised of zeolite-rich rock for the removal of strontium-90 from groundwater. Preliminary column studies were performed using a synthetic groundwater referenced to anticipate field conditions, with a focus on quantifying the competitive ion exchange among five cations (Na+, K+, Ca2+, Mg2+, and Sr2+). Variations of the column configurations addressed the effects of particle size and flow rates on removal efficiency. In general, kinetic effects were not significant for the test conditions. Ongoing studies are focused on the comparison of zeolites obtained from two sources: Teague Mineral Products (Adrian, OR) and Bear River Zeolite (Preston, UT), and on the possible influence of native soil that is mixed with treatment wall material during construction. The results of the performance assessment will support the possible deployment of a full scale treatment wall at a Western New York nuclear facility.

Evaluation of the medicinal use of clay minerals as antibacterial agents.

PubMed

Williams, Lynda B; Haydel, Shelley E

2010-07-01

Natural clays have been used to heal skin infections since the earliest recorded history. Recently our attention was drawn to a clinical use of French green clay (rich in Fe-smectite) for healing Buruli ulcer, a necrotizing fasciitis ('flesh-eating' infection) caused by Mycobacterium ulcerans. These clays and others like them are interesting as they may reveal an antibacterial mechanism that could provide an inexpensive treatment for this and other skin infections, especially in global areas with limited hospitals and medical resources.Microbiological testing of two French green clays, and other clays used traditionally for healing, identified three samples that were effective at killing a broad-spectrum of human pathogens. A clear distinction must be made between 'healing clays' and those we have identified as antibacterial clays. The highly adsorptive properties of many clays may contribute to healing a variety of ailments, although they are not antibacterial. The antibacterial process displayed by the three identified clays is unknown. Therefore, we have investigated the mineralogical and chemical compositions of the antibacterial clays for comparison with non-antibacterial clays in an attempt to elucidate differences that may lead to identification of the antibacterial mechanism(s).The two French green clays used to treat Buruli ulcer, while similar in mineralogy, crystal size, and major element chemistry, have opposite effects on the bacterial populations tested. One clay deposit promoted bacterial growth whereas another killed the bacteria. The reasons for the difference in antibacterial properties thus far show that the bactericidal mechanism is not physical (e.g., an attraction between clay and bacteria), but by a chemical transfer or reaction. The chemical variables are still under investigation.Cation exchange experiments showed that the antibacterial component of the clay can be removed, implicating exchangeable cations in the antibacterial process. Furthermore, aqueous leachates of the antibacterial clays effectively kill the bacteria. Progressively heating the clay leads first to dehydration (200 degrees C), then dehydroxylation (550 degrees C or more), and finally to destruction of the clay mineral structure by (~900 degrees C). By identifying the elements lost after each heating step, and testing the bactericidal effect of the heated product, we eliminated many toxins from consideration (e.g., microbes, organic compounds, volatile elements) and identified several redox-sensitive refractory metals that are common among antibacterial clays. We conclude that the pH and oxidation state buffered by the clay mineral surfaces is key to controlling the solution chemistry and redox related reactions occurring at the bacterial cell wall.

Clay mineral continental amplifier for marine carbon sequestration in a greenhouse ocean

PubMed Central

Kennedy, Martin J.; Wagner, Thomas

2011-01-01

The majority of carbon sequestration at the Earth’s surface occurs in marine continental margin settings within fine-grained sediments whose mineral properties are a function of continental climatic conditions. We report very high mineral surface area (MSA) values of 300 and 570 m2 g in Late Cretaceous black shales from Ocean Drilling Program site 959 of the Deep Ivorian Basin that vary on subcentennial time scales corresponding with abrupt increases from approximately 3 to approximately 18% total organic carbon (TOC). The observed MSA changes with TOC across multiple scales of variability and on a sample-by-sample basis (centimeter scale), provides a rigorous test of a hypothesized influence on organic carbon burial by detrital clay mineral controlled MSA. Changes in TOC also correspond with geochemical and sedimentological evidence for water column anoxia. Bioturbated intervals show a lower organic carbon loading on mineral surface area of 0.1 mg-OC m-2 when compared to 0.4 mg-OC m-2 for laminated and sulfidic sediments. Although either anoxia or mineral surface protection may be capable of producing TOC of < 5%, when brought together they produced the very high TOC (10–18%) apparent in these sediments. This nonlinear response in carbon burial resulted from minor precession-driven changes of continental climate influencing clay mineral properties and runoff from the African continent. This study identifies a previously unrecognized land–sea connection among continental weathering, clay mineral production, and anoxia and a nonlinear effect on marine carbon sequestration during the Coniacian-Santonian Oceanic Anoxic Event 3 in the tropical eastern Atlantic. PMID:21576498

Plant Growth Experiments in Zeoponic Substrates: Applications for Advanced Life Support Systems

NASA Technical Reports Server (NTRS)

Ming, Douglas W.; Gruener, J. E.; Henderson, K. E.; Steinberg, S. L.; Barta, D. J.; Galindo, C.; Henninger, D. L.

2001-01-01

A zeoponic plant-growth system is defined as the cultivation of plants in artificial soils, which have zeolites as a major component (Allen and Ming, 1995). Zeolites are crystalline, hydrated aluminosilicate minerals that have the ability to exchange constituent cations without major change of the mineral structure. Recently, zeoponic systems developed at the National Aeronautics and Space Administration (NASA) slowly release some (Allen et at., 1995) or all of the essential plant-growth nutrients (Ming et at., 1995). These systems have NH4- and K-exchanged clinoptilolite (a natural zeolite) and either natural or synthetic apatite (a calcium phosphate mineral). For the natural apatite system, Ca and P were made available to the plant by the dissolution of apatite. Potassium and NH4-N were made available by ion-exchange reactions involving Ca(2+) from apatite dissolution and K(+) and NH4(+) on zeolitic exchange sites. In addition to NH4-N, K, Ca, and P, the synthetic apatite system also supplied Mg, S, and other micronutrients during dissolution (Figure 1). The overall objective of this research task is to develop zeoponic substrates wherein all plant growth nutrients are supplied by the plant growth medium for several growth seasons with only the addition of water. The substrate is being developed for plant growth in Advanced Life Support (ALS) testbeds (i.e., BioPLEX) and microgravity plant growth experiments. Zeoponic substrates have been used for plant growth experiments on two Space Shuttle flight experiments (STS-60; STS-63; Morrow et aI., 1995). These substrates may be ideally suited for plant growth experiments on the International Space Station and applications in ALS testbeds. However, there are several issues that need to be resolved before zeoponics will be the choice substrate for plant growth experiments in space. The objective of this paper is to provide an overview on recent research directed toward the refinement of zeoponic plant growth substrates.

Studies of anions sorption on natural zeolites.

PubMed

Barczyk, K; Mozgawa, W; Król, M

2014-12-10

This work presents results of FT-IR spectroscopic studies of anions-chromate, phosphate and arsenate - sorbed from aqueous solutions (different concentrations of anions) on zeolites. The sorption has been conducted on natural zeolites from different structural groups, i.e. chabazite, mordenite, ferrierite and clinoptilolite. The Na-forms of sorbents were exchanged with hexadecyltrimethylammonium cations (HDTMA(+)) and organo-zeolites were obtained. External cation exchange capacities (ECEC) of organo-zeolites were measured. Their values are 17mmol/100g for chabazite, 4mmol/100g for mordenite and ferrierite and 10mmol/100g for clinoptilolite. The used initial inputs of HDTMA correspond to 100% and 200% ECEC of the minerals. Organo-modificated sorbents were subsequently used for immobilization of mentioned anions. It was proven that aforementioned anions' sorption causes changes in IR spectra of the HDTMA-zeolites. These alterations are dependent on the kind of anions that were sorbed. In all cases, variations are due to bands corresponding to the characteristic Si-O(Si,Al) vibrations (occurring in alumino- and silicooxygen tetrahedra building spatial framework of zeolites). Alkylammonium surfactant vibrations have also been observed. Systematic changes in the spectra connected with the anion concentration in the initial solution have been revealed. The amounts of sorbed CrO4(2-), AsO4(3-) and PO4(3-) ions were calculated from the difference between their concentrations in solutions before (initial concentration) and after (equilibrium concentration) sorption experiments. Concentrations of anions were determined by spectrophotometric method. Copyright © 2014 Elsevier B.V. All rights reserved.

The Impact of 10 Years of War on Combat Casualty Care Research: A Citation Analysis

DTIC Science & Technology

2012-01-01

2004 74 14 Alam HB, Chen Z, Jaskille A, et al. Application of a zeolite hemostatic agent achieves 100% survival in a lethal model of complex groin...Among the preclinical studies, the most cited was #14 by Alam et al. (2004), ‘‘Application of a zeolite hemostatic agent achieves 100% survival in a...patients. J Trauma. 2006;60:363Y370. 2006 44 47 Wright JK, Kalns J, Wolf EA, et al. Thermal injury resulting from application of a granular mineral

Some engineering aspects of homoionized mixed clay minerals.

PubMed

Oren, Ali Hakan; Kaya, Abidin

2003-05-01

Many studies have been conducted to investigate the physicochemical behavior of pure clay minerals and predict their engineering performance in the field. In this study, the physicochemical properties of an artificial mixture of different clay minerals namely, 40-50% montmorillonite, 20-30% illite and 10-15% kaolin were investigated. The mixture was homoionized with sodium, Na+; calcium, Ca2+; and aluminum, Al3+. The engineering properties studied were consistency limits, sediment volume, compressibility behavior, and hydraulic conductivity. The results revealed that the liquid, plastic and shrinkage limits of soil increased with increasing cation valence. The hydraulic conductivity of the soil also increased with an increase in the valence of the cation at any given void ratio. Aluminum and sodium treated clays had the highest and the lowest modified compression index values, respectively. Furthermore, trivalent cation saturated clayey soil consolidates three times faster than that of monovalent and two times faster than that of divalent. These properties of the soils determined were, in general, similar to those of kaolinite rather than those of montmorillonite. The comparison of the results obtained with the published data in the literature revealed that the physicochemical behavior of the tested clay soil was, in general, similar to that of kaolinite.

Chemical and mineralogical characteristics of French green clays used for healing

USGS Publications Warehouse

Williams, Lynda B.; Haydel, Shelley E.; Giese, Rossman F.; Eberl, Dennis D.

2008-01-01

The worldwide emergence of infectious diseases, together with the increasing incidence of antibiotic-resistant bacteria, elevate the need to properly detect, prevent, and effectively treat these infections. The overuse and misuse of common antibiotics in recent decades stimulates the need to identify new inhibitory agents. Therefore, natural products like clays, that display antibacterial properties, are of particular interest.The absorptive properties of clay minerals are well documented for healing skin and gastrointestinal ailments. However, the antibacterial properties of clays have received less scientific attention. French green clays have recently been shown to heal Buruli ulcer, a necrotic or ‘flesh-eating’ infection caused by Mycobacterium ulcerans. Assessing the antibacterial properties of these clays could provide an inexpensive treatment for Buruli ulcer and other skin infections.Antimicrobial testing of the two clays on a broad-spectrum of bacterial pathogens showed that one clay promotes bacterial growth (possibly provoking a response from the natural immune system), while another kills bacteria or significantly inhibits bacterial growth. This paper compares the mineralogy and chemical composition of the two French green clays used in the treatment of Buruli ulcer.Mineralogically, the two clays are dominated by 1Md illite and Fe-smectite. Comparing the chemistry of the clay minerals and exchangeable ions, we conclude that the chemistry of the clay, and the surface properties that affect pH and oxidation state, control the chemistry of the water used to moisten the clay poultices and contribute the critical antibacterial agent(s) that ultimately debilitate the bacteria.

Evaluation of the medicinal use of clay minerals as antibacterial agents

PubMed Central

Williams, Lynda B.; Haydel, Shelley E.

2010-01-01

Natural clays have been used to heal skin infections since the earliest recorded history. Recently our attention was drawn to a clinical use of French green clay (rich in Fe-smectite) for healing Buruli ulcer, a necrotizing fasciitis (‘flesh-eating’ infection) caused by Mycobacterium ulcerans. These clays and others like them are interesting as they may reveal an antibacterial mechanism that could provide an inexpensive treatment for this and other skin infections, especially in global areas with limited hospitals and medical resources. Microbiological testing of two French green clays, and other clays used traditionally for healing, identified three samples that were effective at killing a broad-spectrum of human pathogens. A clear distinction must be made between ‘healing clays’ and those we have identified as antibacterial clays. The highly adsorptive properties of many clays may contribute to healing a variety of ailments, although they are not antibacterial. The antibacterial process displayed by the three identified clays is unknown. Therefore, we have investigated the mineralogical and chemical compositions of the antibacterial clays for comparison with non-antibacterial clays in an attempt to elucidate differences that may lead to identification of the antibacterial mechanism(s). The two French green clays used to treat Buruli ulcer, while similar in mineralogy, crystal size, and major element chemistry, have opposite effects on the bacterial populations tested. One clay deposit promoted bacterial growth whereas another killed the bacteria. The reasons for the difference in antibacterial properties thus far show that the bactericidal mechanism is not physical (e.g., an attraction between clay and bacteria), but by a chemical transfer or reaction. The chemical variables are still under investigation. Cation exchange experiments showed that the antibacterial component of the clay can be removed, implicating exchangeable cations in the antibacterial process. Furthermore, aqueous leachates of the antibacterial clays effectively kill the bacteria. Progressively heating the clay leads first to dehydration (200°C), then dehydroxylation (550°C or more), and finally to destruction of the clay mineral structure by (~900°C). By identifying the elements lost after each heating step, and testing the bactericidal effect of the heated product, we eliminated many toxins from consideration (e.g., microbes, organic compounds, volatile elements) and identified several redox-sensitive refractory metals that are common among antibacterial clays. We conclude that the pH and oxidation state buffered by the clay mineral surfaces is key to controlling the solution chemistry and redox related reactions occurring at the bacterial cell wall. PMID:20640226

Mineralogy of Sediments on a Cold and Icy Early Mars

NASA Astrophysics Data System (ADS)

Rampe, E. B.; Horgan, B. H. N.; Smith, R.; Scudder, N.; Rutledge, A. M.; Bamber, E.; Morris, R. V.

2017-12-01

The water-related minerals discovered in ancient martian terrains suggest liquid water was abundant on the surface and/or near subsurface during Mars' early history. The debate remains, however, whether these minerals are indicative of a warm and wet or cold and icy climate. To characterize mineral assemblages of cold and icy mafic terrains, we analyzed pro- and supraglacial rocks and sediments from the Collier and Diller glacial valleys in Three Sisters, Oregon. We identified primary and secondary phases using X-ray diffraction (XRD), scanning and transmission electron microscopies with energy dispersive spectroscopy (SEM, TEM, EDS), and visible/short-wave-infrared (VSWIR) and thermal-infrared (TIR) spectroscopies. Samples from both glacial valleys are dominated by primary igneous minerals (i.e., plagioclase and pyroxene). Sediments in the Collier glacial valley contain minor to trace amounts of phyllosilicates and zeolites, but these phases are likely detrital and sourced from hydrothermally altered units on North Sister. We find that the authigenic phases in cold and icy mafic terrains are poorly crystalline and/or amorphous. TEM-EDS analyses of the <2 um size fraction of glacial flour shows the presence of many different nanophase materials, including iron oxides, devitrified volcanic glass, and Fe-Si-Al (e.g., proto-clay) phases. A variety of primary and secondary amorphous materials (e.g., volcanic glass, leached glass, allophane) have been suggested from orbital IR data from Mars, and the CheMin XRD on the Curiosity rover has identified X-ray amorphous materials in all rocks and soils measured to date. The compositions of the Gale Crater amorphous components cannot be explained by primary volcanic glass alone and likely include secondary silicates, iron oxides, and sulfates. We suggest that the prevalence of amorphous materials on the martian surface and the variety of amorphous components may be a signature of a cold and icy climate on Early Mars.

Evolution of ribozymes in the presence of a mineral surface

PubMed Central

Stephenson, James D.; Popović, Milena; Bristow, Thomas F.

2016-01-01

Mineral surfaces are often proposed as the sites of critical processes in the emergence of life. Clay minerals in particular are thought to play significant roles in the origin of life including polymerizing, concentrating, organizing, and protecting biopolymers. In these scenarios, the impact of minerals on biopolymer folding is expected to influence evolutionary processes. These processes include both the initial emergence of functional structures in the presence of the mineral and the subsequent transition away from the mineral-associated niche. The initial evolution of function depends upon the number and distribution of sequences capable of functioning in the presence of the mineral, and the transition to new environments depends upon the overlap between sequences that evolve on the mineral surface and sequences that can perform the same functions in the mineral's absence. To examine these processes, we evolved self-cleaving ribozymes in vitro in the presence or absence of Na-saturated montmorillonite clay mineral particles. Starting from a shared population of random sequences, RNA populations were evolved in parallel, along separate evolutionary trajectories. Comparative sequence analysis and activity assays show that the impact of this clay mineral on functional structure selection was minimal; it neither prevented common structures from emerging, nor did it promote the emergence of new structures. This suggests that montmorillonite does not improve RNA's ability to evolve functional structures; however, it also suggests that RNAs that do evolve in contact with montmorillonite retain the same structures in mineral-free environments, potentially facilitating an evolutionary transition away from a mineral-associated niche. PMID:27793980

Intercalated layered clay composites and their applications

NASA Astrophysics Data System (ADS)

Phukan, Anjali

Supported inorganic reagents are rapidly emerging as new and environmentally acceptable reagents and catalysts. The smectite group of layered clay minerals, such as, Montmorillonite, provides promising character for adsorption, catalytic activity, supports etc. for their large surface area, swelling behavior and ion exchange properties. Aromatic compounds intercalated in layered clays are useful in optical molecular devices. Clay is a unique material for adsorption of heavy metals and various toxic substances. Clay surfaces are known to be catalytically active due to their surface acidity. Acid activated clays possess much improved surface areas and acidities and have higher pore volumes so that can absorb large molecules in the pores. The exchangeable cations in clay minerals play a key role in controlling surface acidity and catalytic activity. Recently, optically active metal-complex-Montmorillonite composites are reported to be active in antiracemization purposes. In view of the above, a research work, relating to the preparation of different modified clay composites and their catalytic applications were carried out. The different aspects and results of the present work have been reported in four major chapters. Chapter I: This is an introductory chapter, which contains a review of the literature regarding clay-based materials. Clay minerals are phyllosilicates with layer structure. Montmorillonite, a member of smectite group of clay, is 2:1 phyllosilicate, where a layer is composed of an octahedral sheet sandwiched by two tetrahedral sheets. Such clay shows cation exchange capacity (CEC) and is expressed in milli-equivalents per 100 gm of dry clay. Clays can be modified by interaction with metal ion, metal complexes, metal cluster and organic cations for various applications. Clays are also modified by treating with acid followed by impregnation with metal salts or ions. Montmorillonite can intercalate suitable metal complexes in excess of CEC to form double or pseudo-trilayer composites. Metal ion and metal ion metal salts intercalated on Montmorillonite are efficient catalysts for Friedel-Crafts (FC) reactions, such as benzylation of benzene, synthesis of Raspberry ketone [4-(4'-hydroxyphenyl)butan-2-one] etc. Montmorillonite clay can be used as a good support for controlled release of pesticides and medicinal drugs, adsorbent for cationic dyes, toxic substances and heavy metals effective adsorbent for radioactive and toxic industrial wastes,...

Mineral resources and land use in Stanislaus County, California

DOE Office of Scientific and Technical Information (OSTI.GOV)

Higgins, C.T.; Dupras, D.L.; Chapman, R.H.

1993-04-01

Stanislaus County covers portions of 3 geologic provinces: Coast Ranges, Great Valley, and Sierra Nevada. Each has been exploited for a distinct set of mineral resources, which include sand and gravel, ball and fire clay, placer gold, manganese, chromite, magnesite, mercury, diatomite, building stone, and mineral pigment. Of these, sand and gravel, clay, and diatomite have been the most important commodities produced recently. Sand and gravel, particularly that along the Tuolumne River, is and will continue to be the county's main mineral product; other potentially important areas include alluvial fans along the west side of the Great Valley. Clay andmore » diatomite could resume importance in the future. There is also potential for quartz-rich specialty sands. Although the county is largely rural, it is undergoing one of the highest growth rates in California. Several new residential communities are being proposed in the county, which would have two major effects on mineral resources: (1) large sources of aggregate will be required for construction, and (2) development of residential areas may preclude mining of resources in those areas. Maps of mineral resources produced by this study, will assist decisions on such potential conflicts in land use.« less

X-ray diffraction study of the mineralogy of microinclusions in fibrous diamond

NASA Astrophysics Data System (ADS)

Smith, Evan; Kopylova, Maya; Dubrovinksy, Leonid

2010-05-01

Fibrous diamond, occurring both as cuboids and as coatings over non-fibrous diamond nuclei, is translucent due to the presence of millions of sub-micron-sized mineral and fluid inclusions. Diamond is strong and relatively inert, making it an excellent vessel to preserve trapped materials. These microinclusions represent direct samples of natural diamond-forming mantle fluids, and are critical for our understanding of diamond genesis. Traditionally, infrared spectroscopy, Raman spectroscopy, secondary ion mass spectrometry, electron microprobe, and FIB-TEM techniques have proven to be effective for the study of microinclusions in diamond. The abundance and random orientation of included minerals in fibrous diamond make them amenable to a powder-type X-ray diffraction (XRD) technique. This technique provides an accurate way to identify included minerals. It also has the advantage of analyzing thousands of inclusions simultaneously, rather than analyzing one inclusion at a time, as with common FIB-TEM techniques. XRD provides a bulk analysis, giving a superior measure of relative abundances of included minerals, as well as potentially accounting for small quantities of minerals that might otherwise be overlooked. We studied fibrous cuboid diamonds with microinclusions from the Democratic Republic of Congo (DRC) (23 samples), Brazil (4 samples), Jericho (1 sample), and Wawa conglomerates (9 samples). XRD analysis was performed at the Bayerisches Geoinstitut (BGI), University of Bayreuth, Germany. The unique XRD setup consists of a RIGAKU FR-D high-brilliance source, OSMIC Inc. Confocal Max-Flux optics, and a SMART APEX 4K CCD area detector. Preliminary XRD studies of microinclusions 8 fibrous diamonds from the DRC showed a prevalence of silicates with structural and coordinated H2O. Sheet silicates constituted 9 out of 13 detected minerals, with phlogopite-biotite micas being present in 4 out of 8 samples. Other detected minerals were 2 chlorite minerals, 2 clay phyllosilicates, serpentine, zircon, a hydrous carbonate and an unidentified zeolite. Many of these phases are deuteric, replacing high-T, high-P micas and carbonates that precipitate from the fluid in the diamond stability field. The ongoing XRD study will (1) elucidate the mineralogy of fluid inclusions in diamonds from Wawa, (2) compare XRD analyses to distinguish between diamonds with carbonatitic versus saline fluid compositions, and (3) reveal whether carbonates occur as crystalline phases or as dissolved or amorphous material in fibrous diamond.

Thermal Properties of Soils

DTIC Science & Technology

1981-12-01

plagio - clase feldspar and pyroxene. The tine fraction may Surface area and its effects contain the clay "sheet" minerals (i.e. kaolinite. illite...Pyroxene, Kaoliniwe Unified By By Ortho. Plagio . amphibole, Basic clay min. Hematite Soil Soil soil petrogr. X.ray clase clase and Igneous and clay and no

Experimental layering development by indenter technique and application to fault rheology differentiation

NASA Astrophysics Data System (ADS)

Gratier, J. P.; Noiriel, C. N.; Renard, F.

2014-12-01

Natural deformation of rocks is often associated with differentiation processes leading to irreversible transformations of their microstructural thus leading in turn to modifications of their rheological properties. The mechanisms of development of such processes at work during diagenesis, metamorphism or fault differentiation are poorly known as they are not easy to reproduce in the laboratory due to the long duration required for most of chemically controlled differentiation processes. Here we show that experimental compaction with layering development, similar to what happens in natural deformation, can be obtained in the laboratory by indenter techniques. Samples of plaster mixed with clay and samples of diatomite loosely interbedded with clays were loaded during several months at 40°C (plaster) and 150°C (diatomite) in presence of their saturated solutions. High-resolution X-ray tomography and SEM studies show that the layering development is a self-organized process. Stress driven dissolution of the soluble minerals (gypsum in plaster, silica in diatomite) is initiated in the zones initially richer in clays because the kinetics of diffusive mass transfer along the clay/soluble mineral interfaces is much faster than along the healed boundaries of the soluble minerals. The passive concentration of the clay minerals amplifies the localization of the dissolution along some layers oriented perpendicular to the maximum compressive stress component. Conversely, in the areas with initial low content in clay and clustered soluble minerals, dissolution is more difficult as the grain boundaries of the soluble species are healed together. These areas are less deformed and they act as rigid objects that concentrate the dissolution near their boundaries thus amplifying the differentiation. Applications to fault processes are discussed: i) localized pressure solution and sealing processes may lead to fault rheology differentiation with a partition between two end-member behaviors: seismic (in sealed zones) and aseismic (in dissolved zones); ii) tectonic layering may lead to highly anisotropic structures with a drastic decrease of the rock strength parallel to the layering.

Particle size and X-ray analysis of Feldspar, Calvert, Ball, and Jordan soils

NASA Technical Reports Server (NTRS)

Chapman, R. S.

1977-01-01

Pipette analysis and X-ray diffraction techniques were employed to characterize the particle size distribution and clay mineral content of the feldspar, calvert, ball, and jordan soils. In general, the ball, calvert, and jordan soils were primarily clay size particles composed of kaolinite and illite whereas the feldspar soil was primarily silt-size particles composed of quartz and feldspar minerals.

Rates and time scales of clay-mineral formation by weathering in saprolitic regoliths of the southern Appalachians from geochemical mass balance

Treesearch

Jason R. Price; Michael A. Velbel; Lina C. Patino

2005-01-01

Rates of clay formation in three watersheds located at the Coweeta Hydrologic Laboratory, western North Carolina, have been determined from solute flux-based mass balance methods. A system of mass balance equations with enough equations and unknowns to allow calculation of secondary mineral formation rates as well as the more commonly determined primary-...

Sorption of Hydrophobic Organic Compounds on Natural Sorbents and Organoclays from Aqueous and Non-Aqueous Solutions: A Mini-Review

PubMed Central

Moyo, Francis; Tandlich, Roman; Wilhelmi, Brendan S.; Balaz, Stefan

2014-01-01

Renewed focus on the sorption of hydrophobic organic chemicals (HOCs) onto mineral surfaces and soil components is required due to the increased and wider range of organic pollutants being released into the environment. This mini-review examines the possibility of the contribution and mechanism of HOC sorption onto clay mineral sorbents such as kaolinite, and soil organic matter and the possible role of both in the prevention of environmental contamination by HOCs. Literature data indicates that certain siloxane surfaces can be hydrophobic. Therefore soils can retain HOCs even at low soil organic levels and the extent will depend on the structure of the pollutant and the type and concentration of clay minerals in the sorbent. Clay minerals are wettable by nonpolar solvents and so sorption of HOCs onto them from aqueous and non-aqueous solutions is possible. This is important for two reasons: firstly, the movement and remediation of soil environments will be a function of the concentration and type of clay minerals in the soil. Secondly, low-cost sorbents such as kaolinite and expandable clays can be added to soils or contaminated environments as temporary retention barriers for HOCs. Inorganic cations sorbed onto the kaolinite have a strong influence on the rate and extent of sorption of hydrophobic organic pollutants onto kaolinite. Structural sorbate classes that can be retained by the kaolinite matrix are limited by hydrogen bonding between hydroxyl groups of the octahedral alumosilicate sheet and the tetrahedral sheet with silicon. Soil organic carbon plays a key role in the sorption of HOCs onto soils, but the extent will be strongly affected by the structure of the organic soil matter and the presence of soot. Structural characterisation of soil organic matter in a particular soil should be conducted during a particular contamination event. Contamination by mining extractants and antibiotics will require renewed focus on the use of the QSAR approaches in the context of the sorption of HOCs onto clay minerals from aqueous and non-aqueous solutions. PMID:24821385

Biomimetic nanoclay scaffolds for bone tissue engineering

NASA Astrophysics Data System (ADS)

Ambre, Avinash Harishchandra

Tissue engineering offers a significant potential alternative to conventional methods for rectifying tissue defects by evoking natural regeneration process via interactions between cells and 3D porous scaffolds. Imparting adequate mechanical properties to biodegradable scaffolds for bone tissue engineering is an important challenge and extends from molecular to macroscale. This work focuses on the use of sodium montmorillonite (Na-MMT) to design polymer composite scaffolds having enhanced mechanical properties along with multiple interdependent properties. Materials design beginning at the molecular level was used in which Na-MMT clay was modified with three different unnatural amino acids and further characterized using Fourier Transform Infrared (FTIR) spectroscopy, X-ray diffraction (XRD). Based on improved bicompatibility with human osteoblasts (bone cells) and intermediate increase in d-spacing of MMT clay (shown by XRD), 5-aminovaleric acid modified clay was further used to prepare biopolymer (chitosan-polygalacturonic acid complex) scaffolds. Osteoblast proliferation in biopolymer scaffolds containing 5-aminovaleric acid modified clay was similar to biopolymer scaffolds containing hydroxyapatite (HAP). A novel process based on biomineralization in bone was designed to prepare 5-aminovaleric acid modified clay capable of imparting multiple properties to the scaffolds. Bone-like apatite was mineralized in modified clay and a novel nanoclay-HAP hybrid (in situ HAPclay) was obtained. FTIR spectroscopy indicated a molecular level organic-inorganic association between the intercalated 5-aminovaleric acid and mineralized HAP. Osteoblasts formed clusters on biopolymer composite films prepared with different weight percent compositions of in situ HAPclay. Human MSCs formed mineralized nodules on composite films and mineralized extracellular matrix (ECM) in composite scaffolds without the use of osteogenic supplements. Polycaprolactone (PCL), a synthetic polymer, was used for preparing composites (films and scaffolds) containing in situ HAPclay. Composite films showed significantly improved nanomechanical properties. Human MSCs formed mineralized ECM on films in absence of osteogenic supplements and were able to infiltrate the scaffolds. Atomic force microscopy imaging of mineralized ECM formed on composite films showed similarities in dimensions, arrangement of collagen and apatite with their natural bone counterparts. This work indicates the potential of in situ HAPclay to impart polymeric scaffolds with osteoinductive, osteoconductive abilities and improve their mechanical properties besides emphasizing nanoclays as cell-instructive materials.

Adsorption Effectivity Test of Andisols Clay-Zeolite (ACZ) Composite as Chromium Hexavalent (Cr(VI)) Ion Adsorbent

NASA Astrophysics Data System (ADS)

Pranoto; Masykur, A.; Nugroho, Y. A.

2018-03-01

Adsorption of chromium hexavalent (Cr(VI)) ion in aqueous solution was investigated. This research was purposed to study the influence of the composition of ACZ, temperature activation, and contact time against adsorption capacity of Cr(VI) ion in aqueous solution. Determination of adsorption effectivity using several parameter such as composition variation of ACZ, contact time, pH, activation temperature, and concentration. In this research, andisol clay and zeolite has been activated with NaOH 3 M and 1 M, respectively. Temperature variation used 100, 200, and 400°C. While composition variation ACZ used 0:100, 25:75, 50:50, 75:25, 100:0. The pH variation was used 2 – 6 and concentration variation using 2, 4, 6, 8, 10, and 12 ppm. Characterization in this research used such as UV-Vis, Surface Area Analyzer (SAA) and Acidity Analysis. Result of this research is known that optimum composition of ACZ was 50:50 with calcination temperature 100°C. Optimum adsorption of Cr(VI) at pH 4 with removal percentage 76.10 % with initial concentration 2 ppm and adsorption capacity is 0.16 mg/g. Adsorption isotherm following freundlich isotherm with value Kf = 0.17 mg/g and value n is 0.963. Based on results, ACZ composite can be used as Cr(VI) ion adsorbents in aqueous solutions.

Investigation of Wyoming Bentonite Hydration in Dry to Water-Saturated Supercritical CO2: Implications for Caprock Integrity

NASA Astrophysics Data System (ADS)

Loring, J. S.; Chen, J.; Thompson, C.; Schaef, T.; Miller, Q. R.; Martin, P. F.; Ilton, E. S.; Qafoku, O.; Felmy, A. R.; Rosso, K. M.

2012-12-01

The effectiveness of geologic sequestration as an enterprise for CO2 storage depends partly on the reactivity of supercritical CO2 (scCO2) with caprock minerals. Injection of scCO2 will displace formation water, and the pore space adjacent to overlying caprocks could eventually be dominated by dry to water-saturated scCO2. Caprock formations have high concentrations of clay minerals, including expandable montmorillonites. Water-bearing scCO2 is highly reactive and capable of hydrating or dehydrating clays, possibly leading to porosity and permeability changes that directly impact caprock performance. Dehydration will cause montmorillonite clay minerals in caprocks to contract, thereby decreasing solid volume and possibly increasing caprock permeability and porosity. On the other hand, water intercalation will cause these clays to expand, thereby increasing solid volume and possibly leading to self-sealing of caprock fractures. Pacific Northwest National Laboratory's Carbon Sequestration Initiative is developing capabilities for studying wet scCO2-mineral reactions in situ. Here, we introduce novel in situ infrared (IR) spectroscopic instrumentation that enables quantitative titrations of reactant minerals with water in scCO2. Results are presented for the infrared spectroscopic titrations of Na-, Ca-, and Mg-saturated Wyoming betonites with water over concentrations ranging from zero to scCO2 saturated. These experiments were carried out at 50°C and 90 bar. Transmission IR spectroscopy was used to measure concentrations of water dissolved in the scCO2 or intercalated into the clays. The titration curves evaluated from the transmission-IR data are compared between the three types of clays to assess the effects of the cation on water partitioning. Single-reflection attenuated total reflection (ATR) IR spectroscopy was used to collect the spectrum of the clays as they hydrate at every total water concentration during the titration. Clay hydration is evidenced by increases in absorbance of the OH stretching and HOH bending modes of the intercalated waters. The ATR-IR data also indicate that CO2 is intercalated in the clay. The asymmetric stretching band of the CO2 molecules that are intercalated in the clay is narrower than that stretching band of bulk scCO2, which indicates that the spectral contribution from rotational fine structure is minimal and the intercalated CO2 is rotationally constrained. A chemometrics analysis of the complete set of ATR-IR spectra spanning the range of total water concentrations covered in the titration finds that there are at least two types of intercalated waters, two types of intercalated CO2 molecules, and the concentrations of these intercalated waters and CO2 molecules are correlated. These quantitative data, when coupled with in situ XRD results that predict interlayer spacing and clay volume, demonstrate that water and CO2 intercalation processes in expandable montmorillonite clays could lead to porosity and permeability changes that directly impact caprock performance.

Neocrystallization, fabrics and age of clay minerals from an exposure of the Moab Fault, Utah

USGS Publications Warehouse

Solum, J.G.; van der Pluijm, B.A.; Peacor, D.R.

2005-01-01

Pronounced changes in clay mineral assemblages are preserved along the Moab Fault (Utah). Gouge is enriched up to ???40% in 1Md illite relative to protolith, whereas altered protolith in the damage zone is enriched ???40% in illite-smectite relative to gouge and up to ???50% relative to protolith. These mineralogical changes indicate that clay gouge is formed not solely through mechanical incorporation of protolith, but also through fault-related authigenesis. The timing of mineralization is determined using 40Ar/39Ar dating of size fractions of fault rocks with varying detrital and authigenic clay content. We applied Ar dating of illite-smectite samples, as well as a newer approach that uses illite polytypes. Our analysis yields overlapping, early Paleocene ages for neoformed (1Md) gouge illite (63??2 Ma) and illite-smectite in the damage zone (60??2 Ma), which are compatible with results elsewhere. These ages represent the latest period of major fault motion, and demonstrate that the fault fabrics are not the result of recent alteration. The clay fabrics in fault rocks are poorly developed, indicating that fluids were not confined to the fault zone by preferentially oriented clays; rather we propose that fluids in the illite-rich gouge were isolated by adjacent lower permeability, illite-smectite-bearing rocks in the damage zone. ?? 2005 Elsevier Ltd. All rights reserved.

The use of fortified soil-clay as on-site system for domestic wastewater purification.

PubMed

Oladoja, N A; Ademoroti, C M A

2006-02-01

The quest for simple, low-cost and high-performance decentralized wastewater treatment system for domestic application in developing nations necessitated this study. Clay samples collected from different deposits in Nigeria were characterized by studying the mineralogical and geochemical composition using X-ray diffraction (XRD) and atomic absorption spectroscopy (AAS), respectively. Three major clay minerals of kaolinite, illite and smectite were identified. The geochemical studies showed the abundance of SiO2, Al2O3 and H2O+ in each of the clay samples. Performance efficiency studies were conducted to determine the best combination ratio of pebbles/soil-clay. Soil-clay fortified by pebbles in combination ratios of 1:3 (i.e. pebbles:soil-clay = 1:3 (w/w) showed the optimum water purification, while the combination 3:1 gave the least. The flow rate studies showed that the wastewater had a longer residence time in non-fortified soil-clay than in fortified soil-clay. Two modes of treatment methods were employed-single and double column treatment methods (SCT and DCT). The two methods gave effluents of good quality characteristics, but those from the DCT were of better quality. The quality of effluents also varies from one clay type to another. The quality of effluents from media containing smectite clay mineral was better than those from other columns. Repeated usage of the fortified clay column showed a decrease of pH, TS and DO, and an increase of COD when monitored over a period of 10 days.

Treatment of radioactive liquid waste by sorption on natural zeolite in Turkey.

PubMed

Osmanlioglu, Ahmet Erdal

2006-09-01

Liquid radioactive waste has been generated from the use of radioactive materials in industrial applications, research and medicine in Turkey. Natural zeolites (clinoptilolite) have been studied for the removal of several key radionuclides ((137)Cs, (60)Co, (90)Sr and (110m)Ag) from liquid radioactive waste. The aim of the present study is to investigate effectiveness of zeolite treatment on decontamination factor (DF) in a combined process (chemical precipitation and adsorption) at the laboratory tests and scale up to the waste treatment plant. In this study, sorption and precipitation techniques were adapted to decontamination of liquid low level waste (LLW). Effective decontamination was achieved when sorbents are used during the chemical precipitation. Natural zeolite samples were taken from different zeolite formations in Turkey. Comparison of the ion-exchange properties of zeolite minerals from different formations shows that Gordes clinoptilolite was the most suitable natural sorbent for radionuclides under dynamic treatment conditions and as an additive for chemical precipitation process. Clinoptilolite were shown to have a high selectivity for (137)Cs and (110m)Ag as sorbent. In the absence of potassium ions, native clinoptilolite removed (60)Co and (90)Sr very effectively from the liquid waste. In the end of this liquid waste treatment, decontamination factor was provided as 430 by using 0.5 mm clinoptilolite at 30 degrees C.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boxley, Chett J.; Kadota, Rod

This research program performed by Ceramatec may significantly increase the beneficial utilization of fly ash, and improve the overall performance of high quality animal litter products. Ceramatec has developed a novel high surface area material, which is capable of ammonia adsorption. High surface area zeolites when combined with agglomerated fly ash can significantly reduce the use of naturally mined materials (i.e. clay bentonite) for animal litter manufacture. This not only preserves natural resources and the natural environment, but it also will reduce CO 2 emissions, via the reduced need for heavy mining equipment. This novel animal litter is made withmore » over 85% of recycled materials, thus preventing their disposition to landfills. The novel litter material is similar to traditional clay-like litters, and it is clumpable and has superior odor control properties.« less

Lithological and hydrological influences on ground-water composition in a heterogeneous carbonate-clay aquifer system

USGS Publications Warehouse

Kauffman, S.J.; Herman, J.S.; Jones, B.F.

1998-01-01

The influence of clay units on ground-water composition was investigated in a heterogeneous carbonate aquifer system of Miocene age in southwest Florida, known as the Intermediate aquifer system. Regionally, the ground water is recharged inland, flows laterally and to greater depths in the aquifer systems, and is discharged vertically upward at the saltwater interface along the coast. A depth profile of water composition was obtained by sampling ground water from discrete intervals within the permeable carbonate units during coring and by squeezing pore water from a core of the less-permeable clay layers. A normative salt analysis of solute compositions in the water indicated a marine origin for both types of water and an evolutionary pathway for the clay water that involves clay diagenesis. The chemical composition of the ground water in the carbonate bedrock is significantly different from that of the pore water in the clay layers. Dissolution of clays and opaline silica results in high silica concentrations relative to water in other parts of the Intermediate aquifer system. Water enriched in chloride relative to the overlying and underlying ground water recharges the aquifer inland where the confining clay layer is absent, and it dissolves carbonate and silicate minerals and reacts with clays along its flow path, eventually reaching this coastal site and resulting in the high chloride and silica concentrations observed in the middle part of the Intermediate aquifer system. Reaction-path modeling suggests that the recharging surficial water mixes with sulfate-rich water upwelling from the Upper Floridan aquifer, and carbonate mineral dissolution and precipitation, weathering and exchange reactions, clay mineral diagenesis, clay and silica dissolution, organic carbon oxidation, and iron and sulfate reduction result in the observed water compositions.A study was conducted to clarify the influence of clay units on ground-water composition in a heterogeneous carbonate aquifer system of Miocene age in southwest Florida. A depth profile of water composition was obtained by sampling ground water from discrete intervals within the permeable carbonate units during coring and by squeezing pore water from a core of the less-permeable clay layers. A normative salt analysis of solute compositions in the water indicated a marine origin for both types of water and an evolutionary pathway for the clay water that involves clay diagenesis. The factors influencing water compositions were determined.

Oxygen radical-mediated mutagenic effect of asbestos on human lymphocytes: suppression by oxygen radical scavengers.

PubMed

Korkina, L G; Durnev, A D; Suslova, T B; Cheremisina, Z P; Daugel-Dauge, N O; Afanas'ev, I B

1992-02-01

The mutagenic effect of chrysotile asbestos fibers and zeolite and latex particles on human lymphocytes in whole blood has been studied. It was concluded that their mutagenic activities were mediated by oxygen radicals because they were inhibited by antioxidant enzymes (SOD and catalase) and oxygen radical scavengers (rutin, ascorbic acid, and bemitil). It was proposed that oxygen radicals were released by phagocytes activated upon exposure to mineral dusts and fibers. The study of lucigenin- and luminol-amplified chemiluminescence of peritoneal macrophages stimulated by chrysotile fibers and zeolite and latex particles has shown that their mutagenic action is probably mediated by different oxygen species, namely, by the iron-oxygen complexes (perferryl ions) plus hydrogen peroxide, hydrogen peroxide, and superoxide ion, respectively. From the oxygen radical scavengers studied, rutin was the most effective inhibitor of the mutagenic effect of mineral fibers and dusts.

Estimating soil zinc concentrations using reflectance spectroscopy

NASA Astrophysics Data System (ADS)

Sun, Weichao; Zhang, Xia

2017-06-01

Soil contamination by heavy metals has been an increasingly severe threat to nature environment and human health. Efficiently investigation of contamination status is essential to soil protection and remediation. Visible and near-infrared reflectance spectroscopy (VNIRS) has been regarded as an alternative for monitoring soil contamination by heavy metals. Generally, the entire VNIR spectral bands are employed to estimate heavy metal concentration, which lacks interpretability and requires much calculation. In this study, 74 soil samples were collected from Hunan Province, China and their reflectance spectra were used to estimate zinc (Zn) concentration in soil. Organic matter and clay minerals have strong adsorption for Zn in soil. Spectral bands associated with organic matter and clay minerals were used for estimation with genetic algorithm based partial least square regression (GA-PLSR). The entire VNIR spectral bands, the bands associated with organic matter and the bands associated with clay minerals were incorporated as comparisons. Root mean square error of prediction, residual prediction deviation, and coefficient of determination (R2) for the model developed using combined bands of organic matter and clay minerals were 329.65 mg kg-1, 1.96 and 0.73, which is better than 341.88 mg kg-1, 1.89 and 0.71 for the entire VNIR spectral bands, 492.65 mg kg-1, 1.31 and 0.40 for the organic matter, and 430.26 mg kg-1, 1.50 and 0.54 for the clay minerals. Additionally, in consideration of atmospheric water vapor absorption in field spectra measurement, combined bands of organic matter and absorption around 2200 nm were used for estimation and achieved high prediction accuracy with R2 reached 0.640. The results indicate huge potential of soil reflectance spectroscopy in estimating Zn concentrations in soil.

Clay mineral distribution along the southern and western Svalbard continental margin in association with contouritic deposition: insights for environmental and oceanographic reconstruction

NASA Astrophysics Data System (ADS)

Musco, Maria Elena; Caricchi, Chiara; Giulia Lucchi, Renata; Princivalle, Francesco; GIorgetti, Giovanna; Caburlotto, Andrea

2017-04-01

The Kveithola and Storfjorden troughs are two glacial depositional systems, situated South of the Svalbard Archipelago (North Western Barents Sea), that during the last glaciation (MIS-2) have hosted ice streams, which contributed to the build-up of the relative Trough Mouth Fans (TMFs) on the continental slope. The sedimentary record contained in TMFs provides several proxies that can be useful for reconstructing the ice-streams dynamics during glacial periods, the onset of deglaciation and the climatic variability during interglacials. The TMF slopes facing the two troughs have been investigated during several international oceanographic cruises: SVAIS onboard R/V BIO Hespérides; EGLACOM, onboard R/V OGS Explora; PNRA Project CORIBAR, onboard R/V Maria S. Marien; Eurofleets-2 PREPARED, onboard RV-G.O. Sars. For this study we have focused on XRD analyses on clay minerals, collected from seven cores, taken during these cruises, and XRF analyses have also been conducted on the whole length of the cores. Clay mineral assemblages are controlled by source rock composition, physical-chemical weathering, transport and depositional mechanisms. In polar areas clay mineral analysis can be used also for reconstructing sedimentary processes, associated with glacial and interglacial conditions. Moreover in the North western Barents Sea smectite is considered a good proxy for reconstructing the North Atlantic Current strength, giving thus additional indication on the palaeoceanographic conditions associated with climatic changes. Here we present a first correlation among these cores, aiming to describe the clay mineral distribution in response to the climatic variations that followed the Last Glacial Maximum and describe the changes in ice-stream dynamics and related oceanographic/environmental changes along the margin.

Quantifying structural states of soft mudrocks

NASA Astrophysics Data System (ADS)

Li, B.; Wong, R. C. K.

2016-05-01

In this paper, a cm model is proposed to quantify structural states of soft mudrocks, which are dependent on clay fractions and porosities. Physical properties of natural and reconstituted soft mudrock samples are used to derive two parameters in the cm model. With the cm model, a simplified homogenization approach is proposed to estimate geomechanical properties and fabric orientation distributions of soft mudrocks based on the mixture theory. Soft mudrocks are treated as a mixture of nonclay minerals and clay-water composites. Nonclay minerals have a high stiffness and serve as a structural framework of mudrocks when they have a high volume fraction. Clay-water composites occupy the void space among nonclay minerals and serve as an in-fill matrix. With the increase of volume fraction of clay-water composites, there is a transition in the structural state from the state of framework supported to the state of matrix supported. The decreases in shear strength and pore size as well as increases in compressibility and anisotropy in fabric are quantitatively related to such transition. The new homogenization approach based on the proposed cm model yields better performance evaluation than common effective medium modeling approaches because the interactions among nonclay minerals and clay-water composites are considered. With wireline logging data, the cm model is applied to quantify the structural states of Colorado shale formations at different depths in the Cold Lake area, Alberta, Canada. Key geomechancial parameters are estimated based on the proposed homogenization approach and the critical intervals with low strength shale formations are identified.

Manganese soil and foliar fertilization of olive plantlets: the effect on leaf mineral and phenolic content and root mycorrhizal colonization.

PubMed

Pasković, Igor; Ćustić, Mirjana Herak; Pecina, Marija; Bronić, Josip; Ban, Dean; Radić, Tomislav; Pošćić, Filip; Jukić Špika, Maja; Soldo, Barbara; Palčić, Igor; Goreta Ban, Smiljana

2018-06-08

The aim of this study was to examine the effect of foliar (Mn_fol) and soil Zeolite-Mn (Mn_ZA) application on leaf mineral, total phenolic and oleuropein content, and mycorrhizae colonization of self-rooted cv. Leccino plantlets grown on calcareous soil. The dissolution of zeolite was 97% when citric acid was applied at 0.05 mM dm -3 , suggesting that organic acids excreted by roots can dissolve modified zeolite (Mn_ZA) making Mn available for plant uptake. The leaf Mn concentration was the highest for Mn_fol treatment at 90 DAT (172 mg kg -1 ) and 150 DAT (70 mg kg -1 ) compared to other treatments. Mn_ZA soil application increased leaf Mn concentration at 150 DAT compared to control and NPK treatment. The oleuropein leaf content was highest for Mn_fol compared to other treatments at 90 DAT and lowest at 150 DAT. Arbuscular mycorrhizal colonization was higher for Mn_fol treatment at 150 DAT compared to all other treatments. Changes in the arbuscular colonization percentage and oleuropein content may be connected to stress conditions provoked by high leaf Mn concentration in Mn_fol treatment at 90 DAT. Mn_ZA application increased leaf Mn concentration at 150 DAT compared to control and NPK treatments. It can be assumed that the dominant mechanism in Mn uptake from modified zeolite is Mn_ZA dissolution through root exudates. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Natural Zeolite Sample and Investigation Its Use in Oil Bleaching Sector

NASA Astrophysics Data System (ADS)

Bilgin, Oyku

2017-12-01

In the sector of oil bleaching, the stored raw oil is subjected to physical and chemical methods such as degumming, neutralization, bleaching, deodorization and winterization. In the process of oil bleaching, the selection of correct bleaching earth in accordance with oil characteristics matters so much. Bleaching earth is an inorganic product used in removing impurities being available within the structures of vegetable, animal oil (sunflower, soya, corn, palm, tallow, rapeseed, fish oils…etc.) and fatty acids, mineral oils (glycerine, paraffin, mineral motor oils. etc.) with the adsorption process. The factors such as low cost of oil bleaching earth, low ratio of oil retaining, high bleaching capacity in spite of using them in small amounts, filter’s delayed blocking by the earth and non-increase of the free acidity of the oil should be taken into consideration. Bleaching earths are processed with some acids in order to widen their surface areas. During this process, a certain amount of acid is left within oil bleaching earths even if it is very little. These acids also increase oil’s acidity by oxidizing oil in the course of bleaching process. In this study, zeolite sample taken from Manisa -Demirci region was used. Following the processes of crushing and sieving, zeolite sample was subjected to chemical analyses according to their grain thickness, microscopic examination, the analyses of XRD and cation exchange capacity and their ore characteristics were determined. Afterwards, it was searched whether zeolite sample has oil bleaching ability or not or whether it can be used as oil bleaching earth or not.

The colloidal chemistry of ceramic clays

NASA Technical Reports Server (NTRS)

Phelps, G. W.

1984-01-01

The colloidal chemistry and mineralogy of two argil minerals were studied. Deposits of kaolin and of ceramic clays in the United States and England are discussed for the probable mechanism of formation. The structural modifications of the bed, original material associated with the clays and the proper use of flocculants are discussed.

Broad-spectrum in vitro antibacterial activities of clay minerals against antibiotic-susceptible and antibiotic-resistant bacterial pathogens

PubMed Central

HAYDEL, SHELLEY E.; REMENIH, CHRISTINE M.; WILLIAMS, LYNDA B.

2008-01-01

SYNOPSIS Objectives The capacity to properly address the worldwide incidence of infectious diseases lies in the ability to detect, prevent, and effectively treat these infections. Therefore, identifying and analyzing inhibitory agents are worthwhile endeavors in an era when few new classes of effective antimicrobials have been developed. The use of geological nanomaterials to heal skin infections has been evident since the earliest recorded history, and specific clay minerals may prove valuable in the treatment of bacterial diseases, including infections for which there are no effective antibiotics, such as Buruli ulcer and multi-drug resistant infections. Methods We have subjected two iron-rich clay minerals, which have previously been used to treat Buruli ulcer patients, to broth culture testing of antibiotic-susceptible and -resistant pathogenic bacteria to assess the feasibility of using clay minerals as therapeutic agents. Results One specific mineral, CsAg02, demonstrated bactericidal activity against pathogenic Escherichia coli, extended-spectrum β-lactamase (ESBL) E. coli, S. enterica serovar Typhimurium, Pseudomonas aeruginosa, and Mycobacterium marinum and a combined bacteriostatic/bactericidal effect against Staphylococcus aureus, penicillin-resistant S. aureus (PRSA), methicillin-resistant S. aureus (MRSA), and Mycobacterium smegmatis, while another mineral with similar structure and bulk crystal chemistry, CsAr02, had no effect on or enhanced bacterial growth. The <0.2 μm fraction of CsAg02 and CsAg02 heated to 200°C or 550°C retained bactericidal activity, while cation-exchanged CsAg02 and CsAg02 heated to 900°C no longer killed E. coli. Conclusions Our results indicate that specific mineral products have intrinsic, heat-stable antibacterial properties, which could provide an inexpensive treatment against numerous human bacterial infections. PMID:18070832

Common clay and shale

USGS Publications Warehouse

Virta, R.L.

2000-01-01

Part of the 1999 Industrial Minerals Review. The clay and shale market in 1999 is reviewed. In the U.S., sales or use of clay and shale increased from 26.4 million st in 1998 to 27.3 million st in 1999, with an estimated 1999 value of production of $143 million. These materials were used to produce structural clay products, lightweight aggregates, cement, and ceramics and refractories. Production statistics for clays and shales and for their uses in 1999 are presented.

Chemical indicators of subsurface temperature applied to hot spring waters of Yellowstone National Park, Wyoming, U.S.A.

USGS Publications Warehouse

Fournier, R.O.; Truesdell, A.H.

1970-01-01

Under favorable conditions the chemistry of hot springs may give reliable indications of subsurface temperatures and circulation patterns. These chemical indicators can be classified by the type of process involved: {A table is presented}. All these indicators have certain limitations. The silica geothermometer gives results independent of the local mineral suite and gas partial pressures, but may be affected by dilution. Alkali ratios are strongly affected by the local mineral suite and the formation of complex ions. Carbonate-chloride ratios are strongly affected by subsurface PCO2. The relative concentration of volatiles can be very misleading in high-pressure liquid systems. In Yellowstone National Park most thermal waters issue from hot, shallow aquifers with pressures in excess of hydrostatic by 2 to 6 bars and with large flows (the flow of hot spring water from the Park is greater than 4000 liters per second). These conditions should be ideal for the use of chemical indicators to estimate aquifer temperatures. In five drill holes aquifer temperatures were within 2??C of that predicted from the silica content of nearby hot springs; the temperature level off at a lower value than predicted in only one hole, and in four other holes drilling was terminated before the predicted aquifer temperature was reached. The temperature-Na/K ratio relationship does not follow any published experimental or empirical curve for water-feldspar or water-clay reactions. We suspect that ion exchange reactions involving zeolites in the Yellowstone rocks result in higher Na/K ratios at given temperatures than result from feldspar or clay reactions. Comparison of SiO2 and Cl/(HCO3 + CO3) suggest that because of higher subsurface PCO2 in Upper Geyser Basin a given Cl/(HCO3 + CO3) ratio there means a higher temperature than in Lower Geyser Basin. No correlation was found in Yellowstone Park between the subsurface regions of highest temperature and the relative concentration of volatile components such as boron and ammonia. ?? 1971.

Common clay and shale

USGS Publications Warehouse

Virta, R.L.

2004-01-01

Part of the 2003 industrial minerals review. The legislation, production, and consumption of common clay and shale are discussed. The average prices of the material and outlook for the market are provided.

Clay-based polymer nanocomposites: research and commercial development.

PubMed

Zeng, Q H; Yu, A B; Lu, G Q; Paul, D R

2005-10-01

This paper reviews the recent research and development of clay-based polymer nanocomposites. Clay minerals, due to their unique layered structure, rich intercalation chemistry and availability at low cost, are promising nanoparticle reinforcements for polymers to manufacture low-cost, lightweight and high performance nanocomposites. We introduce briefly the structure, properties and surface modification of clay minerals, followed by the processing and characterization techniques of polymer nanocomposites. The enhanced and novel properties of such nanocomposites are then discussed, including mechanical, thermal, barrier, electrical conductivity, biodegradability among others. In addition, their available commercial and potential applications in automotive, packaging, coating and pigment, electrical materials, and in particular biomedical fields are highlighted. Finally, the challenges for the future are discussed in terms of processing, characterization and the mechanisms governing the behaviour of these advanced materials.

Subsurface water and clay mineral formation during the early history of Mars.

PubMed

Ehlmann, Bethany L; Mustard, John F; Murchie, Scott L; Bibring, Jean-Pierre; Meunier, Alain; Fraeman, Abigail A; Langevin, Yves

2011-11-02

Clay minerals, recently discovered to be widespread in Mars's Noachian terrains, indicate long-duration interaction between water and rock over 3.7 billion years ago. Analysis of how they formed should indicate what environmental conditions prevailed on early Mars. If clays formed near the surface by weathering, as is common on Earth, their presence would indicate past surface conditions warmer and wetter than at present. However, available data instead indicate substantial Martian clay formation by hydrothermal groundwater circulation and a Noachian rock record dominated by evidence of subsurface waters. Cold, arid conditions with only transient surface water may have characterized Mars's surface for over 4 billion years, since the early-Noachian period, and the longest-duration aqueous, potentially habitable environments may have been in the subsurface.

Shales and geological waste repositories: from microstructure description to macro-scale properties

NASA Astrophysics Data System (ADS)

Tournassat, C.; Steefel, C. I.; Gaboreau, S.

2017-12-01

The mineralogical and chemical properties of clays have been the subject of longstanding study for the long-term disposal of nuclear wastes in geological repositories. The low permeability of clay materials, including shales, provides at least part of the safety functions for radionuclide contaminants confinement. From a geochemical and mineralogical point of view, the high adsorption capacity of clay minerals adds to the effect of low hydraulic conductivities by greatly increasing the retardation of radionuclides and other contaminants, making clays ideal where isolation from the biosphere is desired. While their low permeability and high adsorption capacity are widely acknowledged, it is clear nonetheless that there is a need for an improved understanding of how the chemical and mineralogical properties of shales impact their macroscopic properties. It is at the pore-scale that the chemical properties of clay minerals become important since their electrostatic properties can play a large role. The negative electrostatic potential field at the clay mineral surfaces results in the presence of porosity domains where electroneutrality is not achieved: cations are attracted by the surfaces while anions are repulsed from them, resulting in the presence of a diffuse ion swarm - or diffuse layer. Numerical methods for modeling macroscopic properties of clay media with the consideration of the presence of a diffuse ion swarm have met a growing interest in diverse communities in the past years. In this presentation we will highlight the complex interplays of mineralogical, chemical and microstructural characteristics of clay materials that are ultimately responsible for a remarkable array of macro-scale properties such as specific adsorption, high swelling pressure, semi-permeable membrane properties, and non-Fickian diffusional behavior.

Are Clay Minerals a Climate Constraint? A Review of Prior Data and New Insights on Martian "Weathering Sequences"

NASA Astrophysics Data System (ADS)

Ehlmann, B. L.; Dundar, M.

2016-12-01

Most clay minerals on Mars are Fe/Mg smectites or chlorites, which typically form from mafic protoliths in aqueous chemical systems that are relatively closed and thus require liquid water but not large amounts of water throughput and large-scale chemical leaching. They may thus form either in the subsurface or under select conditions at the surface. However, Al clay minerals, discovered in multiple locations on Mars (Arabia Terra, Northeast Syrtis, Libya Montes Terra Sirenum, Eridania, circum-Hellas, Valles Marineris) may provide evidence of substantial water throughput, if their protolith materials were basaltic. This is because formation of Al clays from a mafic protolith requires removal of Mg and either formation of accompanying Fe oxides or removal of Fe. Thus, the observed sequences of Al clays atop Fe/Mg clays were proposed to represent open system weathering and possibly a late climate optimum around the late Noachian/early Hesperian [1]. Later, they were comprehensively cataloged and reported to represent "weathering sequences" similar to those in terrestrial tropical environments [2]. However, key questions remain; in particular, how much water throughput over what time scale is required? The answer to this question has substantial bearing on the climate of early Mars. Recently, we employed a newly developed, non-parametric Bayesian algorithm [3,4] for semi-automatic identification of rare spectral classes on 139 CRISM images in areas with reported regional-scale occurrences of Al clays. Dozens of detections of the minerals alunite and jarosite were made with the algorithm and then verified by manual analysis. These sulfate hydroxides form only at low pHs, and thus their presence tightly constrains water chemistry. Here, we discuss the evidence for low pH surface waters associated with the weathering sequences and their implications for the cumulative duration of surface weathering. [1] Ehlmann et al., 2011, Nature | [2] Carter et al., 2015, Icarus | [3] Dundar et al., 2016, IEEE WHISPERS proceedings | [4] Ehlmann & Dundar, submitted

Adsorption of organic ligands on low surface charge clay minerals: the composition in the aqueous interface region.

PubMed

Jelavić, S; Stipp, S L S; Bovet, N

2018-06-27

An understanding of the mechanisms that control the adsorption of organic molecules on clay minerals is of interest in several branches of science and industry. Oil production using low salinity injection fluids can increase yields by as much as 40% over standard injection with seawater or formation water. The mechanism responsible for the low salinity response is still debated, but one hypothesis is a change in pore surface wettability. Organic contamination in soil and drinking water aquifers is a challenge for municipal water suppliers and for agriculture. A better understanding is needed for how mineral species, solution composition and pH affect the desorption of low molecular weight organic ligands from clay minerals and consequently their wettability. We used X-ray photoelectron spectroscopy under cryogenic conditions to investigate the in situ composition in the mineral-solution interface region in a series of experiments with a range of pH and ion concentrations. We demonstrate that both chlorite and kaolinite release organic molecules under conditions relevant for low salinity water flooding. This release increases with a higher solution pH but is only slightly affected by the character of the organic ligand. This is consistent with the observation that low salinity enhanced oil recovery correlates with the presence of chlorite and kaolinite. Our results indicate that the pore surface charge and salinity of formation water and injection fluids are key parameters in determining the low salinity response. In general, our results imply that clay mineral surface charge influences the composition in the interface through an affinity for organic molecules.

Petrography and geochemistry of the Middle Devonian coal from Luquan, Yunnan Province, China

USGS Publications Warehouse

Dai, S.; Han, D.; Chou, C.-L.

2006-01-01

Coals from Luquan, Yunnan Province, China, have high contents of cutinite and microsporinite, with an average of 55 and 33.5 vol%, respectively, (on a mineral-free basis). The coals are classified as cutinitic liptobiolith, sporinite-rich durain, cutinite-rich durain, and sporinitic liptobiolith. These four liptinite-rich coals are often interlayered within the coal bed section and vary transversely within the coal bed. The vitrinite content varies from as low as 1.6-20.5% (mineral-free basis), and it is dominated by collodetrinite, collotelinite, and corpogelinite. The maceral composition may be attributed to the type of the peat-forming plant communities. Moreover, the Luquan coals are characterized by high contents of volatile matter, hydrogen, and oxygen, and the high values of the atomic hydrogen to carbon ratio as a result of the maceral composition. As compared with the common Chinese coals and the upper continental crust, the Luquan coals are enriched in Li, B, Cu, Ga, Se, Rb, Mo, Ba, Pb, Bi, and U, with averages of 99.9, 250, 111, 24.4, 4.55, 130, 58.8, 1276, 162, 3.85, and 34.1 ??g/g, respectively. The SEM-EDX results show that V, Cr, Ga, and Rb occur mainly in clay minerals, and Cu and Pb are associated with clay minerals and pyrite, and Mo and U are mainly in clay minerals and organic matter. Barite and clay minerals are the main carrier of barium. The high B and U contents are probably resulted from deep seawater influence during coal formation. ?? 2005 Elsevier Ltd. All rights reserved.

Unraveling the antibacterial mode of action of a clay from the Colombian Amazon.

PubMed

Londono, Sandra Carolina; Williams, Lynda B

2016-04-01

Natural antibacterial clays can inhibit growth of human pathogens; therefore, understanding the antibacterial mode of action may lead to new applications for health. The antibacterial modes of action have shown differences based on mineralogical constraints. Here we investigate a natural clay from the Colombian Amazon (AMZ) known to the Uitoto natives as a healing clay. The physical and chemical properties of the AMZ clay were compared to standard reference materials: smectite (SWy-1) and kaolinite (API #5) that represent the major minerals in AMZ. We tested model Gram-negative (Escherichia coli ATCC #25922) and Gram-positive (Bacillus subtilis ATCC #6633) bacteria to assess the clay's antibacterial effectiveness against different bacterial types. The chemical and physical changes in the microbes were examined using bioimaging and mass spectrometry of clay digests and aqueous leachates. Results indicate that a single dose of AMZ clay (250 mg/mL) induced a 4-6 order of magnitude reduction in cell viability, unlike the reference clays that did not impact bacterial survival. AMZ clay possesses a relatively high specific surface area (51.23 m(2)/g) and much higher total surface area (278.82 m(2)/g) than the reference clays. In aqueous suspensions (50 mg clay/mL water), soluble metals are released and the minerals buffer fluid pH between 4.1 and 4.5. We propose that the clay facilitates chemical interactions detrimental to bacteria by absorbing nutrients (e.g., Mg, P) and potentially supplying metals (e.g., Al) toxic to bacteria. This study demonstrates that native traditional knowledge can direct scientific studies.

Field trip guidebook on environmental impact of clays along the upper Texas coast

NASA Technical Reports Server (NTRS)

Garcia, Theron D.; Ming, Douglas W.; Tuck, Lisa Kay

1991-01-01

The field trip was prepared to provide an opportunity to see first hand some the environmental hazards associated with clays in the Houston, Texas area. Because of the very high clay content in area soils and underlying Beaumont Formation clay, Houston is a fitting location to host the Clay Mineral Society. Examinations were made of (1) expansive soils, (2) subsidence and surface faulting, and (3) a landfill located southeast of Houston at the Gulf Coast Waste Disposal Authority where clay is part of the liner material.

Size distributions of coastal ocean suspended particulate inorganic matter: Amorphous silica and clay minerals and their dynamics

NASA Astrophysics Data System (ADS)

Zhang, Xiaodong; Stavn, Robert H.; Falster, Alexander U.; Rick, Johannes J.; Gray, Deric; Gould, Richard W.

2017-04-01

Particulate inorganic matter (PIM) is a key component in estuarine and coastal systems and plays a critical role in trace metal cycling. Better understanding of coastal dynamics and biogeochemistry requires improved quantification of PIM in terms of its concentration, size distribution, and mineral species composition. The angular pattern of light scattering contains detailed information about the size and composition of particles. These volume scattering functions (VSFs) were measured in Mobile Bay, Alabama, USA, a dynamic, PIM dominated coastal environment. From measured VSFs, we determined through inversion the particle size distributions (PSDs) of major components of PIM, amorphous silica and clay minerals. An innovation here is the extension of our reported PSDs significantly into the submicron range. The PSDs of autochthonous amorphous silica exhibit two unique features: a peak centered at about 0.8 μm between 0.2 and 4 μm and a very broad shoulder essentially extending from 4 μm to >100 μm. With an active and steady particle source from blooming diatoms, the shapes of amorphous silica PSDs for sizes <10 μm varied little across the study area, but showed more particles of sizes >10 μm inside the bay, likely due to wind-induced resuspension of larger frustules that have settled. Compared to autochthonous amorphous silica, the allochthonous clay minerals are denser and exhibit relatively narrower PSDs with peaks located between 1 and 4 μm. Preferential settling of larger mineral particles as well as the smaller but denser illite component further narrowed the size distributions of clay minerals as they were being transported outside the bay. The derived PSDs also indicated a very dynamic situation in Mobile Bay when a cold weather front passed through during the experiment. With northerly winds of speeds up to 15 m s-1, both amorphous silica and clay minerals showed a dramatic increase in concentration and broadening in size distribution outside the exit of the barrier islands, indicative of wind-induced resuspension and subsequent advection of particles out of Mobile Bay. While collectively recognized as the PIM, amorphous silica and clay minerals, as shown in this study, possess very different size distributions. Considering how differences in PSDs and the associated particle areas will effect differences in sorption/desorption properties of these components, the results also demonstrate the potential of applying VSF-inversion in studying biogeochemistry in the estuarine-coastal ocean system.

A Comparative Study of T1 and T2 Relaxation in Shale

NASA Astrophysics Data System (ADS)

Keating, K.; Obasi, C. C.; Pashin, J. C.

2015-12-01

Nuclear magnetic resonance (NMR) relaxation measurement have been used extensively in petroleum and, more recently, in groundwater resource evaluation to estimate the porosity, pore-size distributions, permeability, fluid saturation, and fluid mobility. In shale, the transverse decay rate of NMR signal is sensitive to the microporosity, but is also affected by the paramagnetic contributions of clay and other iron-bearing minerals. Furthermore, contrasts in the magnetic susceptibility of the mineral matrix and pore fluids that result in an inhomogeneous magnetic field within the pore space results in an extra term in transverse relaxation. These issues can cause errors in NMR-based estimates of pore-size distribution and permeability. In this study we compare T1 and T2 relaxation time distributions in order to study the molecular mechanism of relaxation in brine-saturated mixtures of clay and other common minerals. We collected measurements on a range of mixtures of clay minerals common in shale (illite, glauconite, celadonite, chamosite, montmorillonite and kaolinite) and pyrite. To constrain the interpretation of the NMR data, we measured the magnetic susceptibility and surface area of all samples. We are confident that by accounting for the presence and variations of clay and pyrite in shale, we can substantially improve both the NMR estimate of pore-size distribution and permeability.

Arsenic mobilization in shallow aquifers due to CO 2 intrusion from storage reservoirs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xiao, Ting; Dai, Zhenxue; Viswanathan, Hari S.

We developed an integrated framework of combined batch experiments and reactive transport simulations to quantify water-rock-CO 2 interactions and arsenic (As) mobilization responses to CO 2 and/or saline water leakage into USDWs. Experimental and simulation results suggest that when CO 2 is introduced, pH drops immediately that initiates release of As from clay minerals. Calcite dissolution can increase pH slightly and cause As re-adsorption. Thus, the mineralogy of the USDW is ultimately a determining factor of arsenic fate and transport. Salient results suggest that: (1) As desorption/adsorption from/onto clay minerals is the major reaction controlling its mobilization, and clay mineralsmore » could mitigate As mobilization with surface complexation reactions; (2) dissolution of available calcite plays a critical role in buffering pH; (3) high salinity in general hinders As release from minerals; and (4) the magnitude and quantitative uncertainty of As mobilization are predicated on the values of reaction rates and surface area of calcite, adsorption surface areas and equilibrium constants of clay minerals, and cation exchange capacity. Results of this study are intended to improve ability to quantify risks associated with potential leakage of reservoir fluids into shallow aquifers, in particular the possible environmental impacts of As mobilization at carbon sequestration sites.« less

Arsenic mobilization in shallow aquifers due to CO 2 intrusion from storage reservoirs

DOE PAGES

Xiao, Ting; Dai, Zhenxue; Viswanathan, Hari S.; ...

2017-06-05

We developed an integrated framework of combined batch experiments and reactive transport simulations to quantify water-rock-CO 2 interactions and arsenic (As) mobilization responses to CO 2 and/or saline water leakage into USDWs. Experimental and simulation results suggest that when CO 2 is introduced, pH drops immediately that initiates release of As from clay minerals. Calcite dissolution can increase pH slightly and cause As re-adsorption. Thus, the mineralogy of the USDW is ultimately a determining factor of arsenic fate and transport. Salient results suggest that: (1) As desorption/adsorption from/onto clay minerals is the major reaction controlling its mobilization, and clay mineralsmore » could mitigate As mobilization with surface complexation reactions; (2) dissolution of available calcite plays a critical role in buffering pH; (3) high salinity in general hinders As release from minerals; and (4) the magnitude and quantitative uncertainty of As mobilization are predicated on the values of reaction rates and surface area of calcite, adsorption surface areas and equilibrium constants of clay minerals, and cation exchange capacity. Results of this study are intended to improve ability to quantify risks associated with potential leakage of reservoir fluids into shallow aquifers, in particular the possible environmental impacts of As mobilization at carbon sequestration sites.« less

Thermo Gravimetric and Differential Thermal Analysis of Clay of Western Rajasthan (india)

NASA Astrophysics Data System (ADS)

Shekhawat, M. S.

The paper presents the study of thermo gravimetric and differential thermal analysis of blended clay. Western part of Rajasthan (India) is rich resource of Ball clays and it is mainly used by porcelain, sanitary ware, and tile industry. The quality and grade of clay available in the region vary from one deposit to other. To upgrade the fired colour and strength properties, different variety of clays may be blended together. The paper compares the results of thermal analysis one of blended clay B2 with reference clay of Ukraine which is imported by industries owners. The result revealed that the blended clay is having mineral kaolinite while the Ukrainian clay is Halloysite.

Swelling properties of montmorillonite and beidellite clay minerals from molecular simulation: Comparison of temperature interlayer cation, and charge location effects

DOE PAGES

Teich-McGoldrick, Stephanie L.; Greathouse, Jeffery A.; Jove-Colon, Carlos F.; ...

2015-08-27

In this study, the swelling properties of smectite clay minerals are relevant to many engineering applications including environmental remediation, repository design for nuclear waste disposal, borehole stability in drilling operations, and additives for numerous industrial processes and commercial products. We used molecular dynamics and grand canonical Monte Carlo simulations to study the effects of layer charge location, interlayer cation, and temperature on intracrystalline swelling of montmorillonite and beidellite clay minerals. For a beidellite model with layer charge exclusively in the tetrahedral sheet, strong ion–surface interactions shift the onset of the two-layer hydrate to higher water contents. In contrast, for amore » montmorillonite model with layer charge exclusively in the octahedral sheet, weaker ion–surface interactions result in the formation of fully hydrated ions (two-layer hydrate) at much lower water contents. Clay hydration enthalpies and interlayer atomic density profiles are consistent with the swelling results. Water adsorption isotherms from grand canonical Monte Carlo simulations are used to relate interlayer hydration states to relative humidity, in good agreement with experimental findings.« less

Investigating the Thermal Limit of Clay Minerals for Applications in Nuclear Waste Repository Design

NASA Astrophysics Data System (ADS)

Matteo, E. N.; Miller, A. W.; Kruichak, J.; Mills, M.; Tellez, H.; Wang, Y.

2013-12-01

Clay minerals are likely candidates to aid in nuclear waste isolation due to their low permeability, favorable swelling properties, and high cation sorption capacities. Establishing the thermal limit for clay minerals in a nuclear waste repository is a potentially important component of repository design, as flexibility of the heat load within the repository can have a major impact on the selection of repository design. For example, the thermal limit plays a critical role in the time that waste packages would need to cool before being transferred to the repository. Understanding the chemical and physical changes that occur in clay minerals at various temperatures above the current thermal limit (of 100 °C) can enable decision-makers with information critical to evaluating the potential trade-offs of increasing the thermal limit within the repository. Most critical is gaining understanding of how varying thermal conditions in the repository will impact radionuclide sorption and transport in clay materials either as engineered barriers or as disposal media. A variety of clays (illite, mixed layer illite/smectite, montmorillonite, and palygorskite) were heated for a range of temperatures between 100-500 °C. These samples were characterized by a variety of methods, including nitrogen adsorption, x-ray diffraction, thermogravimetric analysis, barium chloride exchange for cation exchange capacity (CEC), and iodide sorption. The nitrogen porosimetry shows that for all the clays, thermally-induced changes in BET surface area are dominated by collapse/creation of the microporosity, i.e. pore diameters < 17 angstroms. Changes in micro porosity (relative to no heat treatment) are most significant for heat treatments 300 °C and above. Alterations are also seen in the chemical properties (CEC, XRD, iodide sorption) of clays, and like pore size distribution changes, are most significant above 300 °C. Overall, the results imply that changes seen in pores size distribution correlate with cation exchange capacity and cation exchange processes. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's Nation Nuclear Security Administration under contract DE-AC04-94AL85000. SAND Number: 2013-6352A.

Importance of clay size minerals for Fe(III) respiration in a petroleum-contaminated aquifer

USGS Publications Warehouse

Shelobolina, Evgenya S.; Anderson, Robert T.; Vodyanitskii, Yury N.; Sivtsov, Anatolii V.; Yuretich, Richard; Lovely, Derek R.

2004-01-01

The availability of Fe(III)-bearing minerals for dissimilatory Fe(III) reduction was evaluated in sediments from a petroleum-contaminated sandy aquifer near Bemidji, Minnesota (USA). First, the sediments from a contaminated area of the aquifer, in which Fe(III) reduction was the predominant terminal electron accepting process, were compared with sediments from a nearby, uncontaminated site. Data from 0.5 m HCl extraction of different size fractions of the sediments revealed that the clay size fraction contributed a significant portion of the ‘bio-available’ Fe(III) in the background sediment and was the most depleted in ‘bio-available’ Fe(III) in the iron-reducing sediment. Analytical transmission electron microscopy (TEM) revealed the disappearance of thermodynamically unstable Fe(III) and Mn(IV) hydroxides (ferrihydrite and Fe vernadite), as well as a decrease in the abundance of goethite and lepidocrocite in the clay size fraction from the contaminated sediment. TEM observations and X-ray diffraction examination did not provide strong evidence of Fe(III)-reduction-related changes within another potential source of ‘bio-available’ Fe(III) in the clay size fraction – ferruginous phyllosilicates. However, further testing in the laboratory with sediments from the methanogenic portion of the aquifer that were depleted in microbially reducible Fe(III) revealed the potential for microbial reduction of Fe(III) associated with phyllosilicates. Addition of a clay size fraction from the uncontaminated sediment, as well as Fe(III)-coated kaolin and ferruginous nontronite SWa-1, as sources of poorly crystalline Fe(III) hydroxides and structural iron of phyllosilicates respectively, lowered steady-state hydrogen concentrations consistent with a stimulation of Fe(III) reduction in laboratory incubations of methanogenic sediments. There was no change in hydrogen concentration when non-ferruginous clays or no minerals were added. This demonstrated that Fe(III)-bearing clay size minerals were essential for microbial Fe(III) reduction and suggested that both potential sources of ‘bio-available’ Fe(III) in the clay size fraction, poorly crystalline Fe(III) hydroxides and structural Fe(III) of phyllosilicates, were important sources of electron acceptor for indigenous iron-reducing microorganisms in this aquifer.

Crystal structure control of aluminized clay minerals on the mobility of caesium in contaminated soil environments

NASA Astrophysics Data System (ADS)

Dzene, Liva; Ferrage, Eric; Viennet, Jean-Christophe; Tertre, Emmanuel; Hubert, Fabien

2017-02-01

Radioactive caesium pollution resulting from Fukushima Dai-ichi and Chernobyl nuclear plant accidents involves strong interactions between Cs+ and clays, especially vermiculite-type minerals. In acidic soil environments, such as in Fukushima area, vermiculite is subjected to weathering processes, resulting in aluminization. The crystal structure of aluminized clays and its implications for Cs+ mobility in soils remain poorly understood due to the mixture of these minerals with other clays and organic matter. We performed acidic weathering of a vermiculite to mimic the aluminization process in soils. Combination of structure analysis and Cs+ extractability measurements show that the increase of aluminization is accompanied by an increase in Cs+ mobility. Crystal structure model for aluminized vermiculite is based on the interstratification of unaltered vermiculite layers and aluminized layers within the same particle. Cs+ in vermiculite layers is poorly mobile, while the extractability of Cs+ is greatly enhanced in aluminized layers. The overall reactivity of the weathered clay (cation exchange capacity, Cs+ mobility) is then governed by the relative abundance of the two types of layers. The proposed layer model for aluminized vermiculite with two coexisting populations of caesium is of prime importance for predicting the fate of caesium in contaminated soil environments.

Ball clay

USGS Publications Warehouse

Virta, R.L.

2000-01-01

Part of the 1999 Industrial Minerals Review. The state of the ball clay industry in 1999 is presented. Record highs in the sales and use of ball clay were attained in 1999 due to the continued strength of the U.S. economy. U.S. production was estimated at 1.25 million st for the year, with more than half of that amount mined in Tennessee. Details of the consumption, price, imports, and exports of ball clay in 1999 and the outlook for ball clay over the next few years are provided.

Clay Minerals as Solid Acids and Their Catalytic Properties.

ERIC Educational Resources Information Center

Helsen, J.

1982-01-01

Discusses catalytic properties of clays, attributed to acidity of the clay surface. The formation of carbonium ions on montmorillonite is used as a demonstration of the presence of surface acidity, the enhanced dissociation of water molecules when polarized by cations, and the way the surface can interact with organic substances. (Author/JN)

Primordial clays on Mars formed beneath a steam or supercritical atmosphere.

PubMed

Cannon, Kevin M; Parman, Stephen W; Mustard, John F

2017-12-06

On Mars, clay minerals are widespread in terrains that date back to the Noachian period (4.1 billion to 3.7 billion years ago). It is thought that the Martian basaltic crust reacted with liquid water during this time to form hydrated clay minerals. Here we propose, however, that a substantial proportion of these clays was formed when Mars' primary crust reacted with a dense steam or supercritical atmosphere of water and carbon dioxide that was outgassed during magma ocean cooling. We present experimental evidence that shows rapid clay formation under conditions that would have been present at the base of such an atmosphere and also deeper in the porous crust. Furthermore, we explore the fate of a primordial clay-rich layer with the help of a parameterized crustal evolution model; we find that the primordial clay is locally disrupted by impacts and buried by impact-ejected material and by erupted volcanic material, but that it survives as a mostly coherent layer at depth, with limited surface exposures. These exposures are similar to those observed in remotely sensed orbital data from Mars. Our results can explain the present distribution of many clays on Mars, and the anomalously low density of the Martian crust in comparison with expectations.

Removal of diphenhydramine from water by swelling clay minerals.

PubMed

Li, Zhaohui; Chang, Po-Hsiang; Jiang, Wei-Teh; Jean, Jiin-Shuh; Hong, Hanlie; Liao, Libing

2011-08-01

Frequent detection of pharmaceuticals in surface water and wastewater attracted renewed attention on studying interactions between pharmaceuticals and sludge or biosolids generated from wastewater treatment. Less attention was focused on studying interactions between pharmaceuticals and clay minerals, important soil and sediment components. This research targeted on investigating interactions between diphenhydramine (DPH), an important antihistamine drug, and a montmorillonite, a swelling clay, in aqueous solution. Stoichiometric desorption of exchangeable cations accompanying DPH adsorption confirmed that cation exchange was the most important mechanism of DPH uptake by the swelling clay. When the solution pH was below the pK(a) of DPH, its adsorption on the swelling clay was less affected by pH. Increasing solution pH above the pK(a) value resulted in a decrease in DPH adsorption by the clay. An increase in d(001) spacing at a high DPH loading level suggested interlayer adsorption, thus, intercalation of DPH. The results from this study showed that swelling clays are a good environmental sink for weak acidic drugs like DPH. In addition, the large cation exchange capacity and surface area make the clay a good candidate to remove cationic pharmaceuticals from the effluent of wastewater treatment facilities. Copyright © 2011 Elsevier Inc. All rights reserved.

Primordial clays on Mars formed beneath a steam or supercritical atmosphere

NASA Astrophysics Data System (ADS)

Cannon, Kevin M.; Parman, Stephen W.; Mustard, John F.

2017-12-01

On Mars, clay minerals are widespread in terrains that date back to the Noachian period (4.1 billion to 3.7 billion years ago). It is thought that the Martian basaltic crust reacted with liquid water during this time to form hydrated clay minerals. Here we propose, however, that a substantial proportion of these clays was formed when Mars’ primary crust reacted with a dense steam or supercritical atmosphere of water and carbon dioxide that was outgassed during magma ocean cooling. We present experimental evidence that shows rapid clay formation under conditions that would have been present at the base of such an atmosphere and also deeper in the porous crust. Furthermore, we explore the fate of a primordial clay-rich layer with the help of a parameterized crustal evolution model; we find that the primordial clay is locally disrupted by impacts and buried by impact-ejected material and by erupted volcanic material, but that it survives as a mostly coherent layer at depth, with limited surface exposures. These exposures are similar to those observed in remotely sensed orbital data from Mars. Our results can explain the present distribution of many clays on Mars, and the anomalously low density of the Martian crust in comparison with expectations.

SUPPRESSION OF HUMORAL IMMUNE RESPONSES BY 2,3,7,8-TETRACHLORODIBENZO-p-DIOXIN INTERCALATED IN SMECTITE CLAY

PubMed Central

Boyd, Stephen A.; Johnston, Cliff T.; Pinnavaia, Thomas J.; Kaminski, Norbert E.; Teppen, Brian J.; Li, Hui; Khan, Bushra; Crawford, Robert B.; Kovalova, Natalia; Kim, Seong-Su; Shao, Hua; Gu, Cheng; Kaplan, Barbara L.F.

2018-01-01

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a highly toxic environmental contaminant found in soils and sediments. Because of its exceptionally low water solubility, this compound exists predominantly in the sorbed state in natural environments. Clay minerals, especially expandable smectite clays, are one of the major component geosorbents in soils and sediments that can function as an effective adsorbent for environmental dioxins, including TCDD. In this study, TCDD was intercalated in the smectite clay saponite by an incipient wetness method. The primary goal of this study was to intercalate TCDD in natural K-saponite clay and evaluate its immunotoxic effects in vivo. The relative bioavailability of TCDD was evaluated by comparing the metabolic activity of TCDD administered in the adsorbed state as an intercalate in saponite and freely dissolved in corn oil. This comparison revealed nearly identical TCDD-induced suppression of humoral immunity, a well-established and sensitive sequela, in a mammalian (mouse) model. This result suggests that TCDD adsorbed by clays is likely to be available for biouptake and biodistribution in mammals, consistent with previous observations of TCDD in livestock exposed to dioxin-contaminated ball clays that were used as feed additives. Adsorption of TCDD by clay minerals does not appear to mitigate risk associated with TCDD exposure substantially. PMID:21994089

In situ immobilisation of toxic metals in soil using Maifan stone and illite/smectite clay.

PubMed

Ou, Jieyong; Li, Hong; Yan, Zengguang; Zhou, Youya; Bai, Liping; Zhang, Chaoyan; Wang, Xuedong; Chen, Guikui

2018-03-15

Clay minerals have been proposed as amendments for remediating metal-contaminated soils owing to their abundant reserves, high performance, simplicity of use and low cost. Two novel clay minerals, Maifan stone and illite/smectite clay, were examined in the in situ immobilisation of soil metals. The application of 0.5% Maifan stone or illite/smectite clay to field soils significantly decreased the fractions of diethylenetriaminepentaacetic acid (DTPA)-extractable Cd, Ni, Cr, Zn, Cu and Pb. Furthermore, reductions of 35.4% and 7.0% in the DTPA-extractable fraction of Cd were obtained with the Maifan stone and illite/smectite clay treatments, respectively, which also significantly reduced the uptake of Cd, Ni, Cr, Zn, Cu and Pb in the edible parts of Brassica rapa subspecies pekinensis, Brassica campestris and Spinacia oleracea. Quantitatively, the Maifan stone treatment reduced the metal uptake in B. rapa ssp. Pekinensis, B. campestris and S. oleracea from 11.6% to 62.2%, 4.6% to 41.8% and 11.3% to 58.2%, respectively, whereas illite/smectite clay produced reductions of 8.5% to 62.8% and 4.2% to 37.6% in the metal uptake in B. rapa ssp. Pekinensis and B. campestris, respectively. Therefore, both Maifan stone and illite/smectite clay are promising amendments for contaminated soil remediation.

Mars surface weathering products and spectral analogs: Palagonites and synthetic iron minerals

NASA Technical Reports Server (NTRS)

Golden, D. C.; Ming, D. W.; Morris, R. V.; Lauer, H. V., Jr.

1992-01-01

There are several hypotheses regarding the formation of Martian surface fines. These surface fines are thought to be products of weathering processes occurring on Mars. Four major weathering environments of igneous rocks on Mars have been proposed; (1) impact induced hydrothermal alterations; (2) subpermafrost igneous intrusion; (3) solid-gas surface reactions; and (4) subaerial igneous intrusion over permafrost. Although one or more of these processes may be important on the Martian surface, one factor in common for all these processes is the reaction of solid or molten basalt with water (solid, liquid, or gas). These proposed processes, with the exception of solid-gas surface reactions, are transient processes. The most likely product of transient hydrothermal processes are layer silicates, zeolites, hydrous iron oxides and palagonites. The long-term instability of hydrous clay minerals under present Martian conditions has been predicted; however, the persistence of such minerals due to slow kinetics of dehydration, or entrapment in permafrost, where the activity of water is high, can not be excluded. Anhydrous oxides of iron (e.g., hematite and maghemite) are thought to be stable under present Martian surface conditions. Oxidative weathering of sulfide minerals associated with Martian basalts has been proposed. Weathering of sulfide minerals leads to a potentially acidic permafrost and the formation of Fe(3) oxides and sulfates. Weathering of basalts under acidic conditions may lead to the formation of kaolinite through metastable halloysite and metahalloysite. Kaolinite, if present, is thought to be a thermodynamically stable phase at the Martian surface. Fine materials on Mars are important in that they influence the surface spectral properties; these fines are globally distributed on Mars by the dust storms and this fraction will have the highest surface area which should act as a sink for most of the absorbed volatiles near the surface of Mars. Therefore, the objectives of this study were to: (1) examine the fine fraction mineralogy of several palagonitic materials from Hawaii; and (2) compare spectral properties of palagonites and submicron sized synthetic iron oxides with the spectral properties of the Martian surface.

Engineered Structured Sorbents for the Adsorption of Carbon Dioxide and Water Vapor from Manned Spacecraft Atmospheres: Applications and Testing 2008/2009

NASA Technical Reports Server (NTRS)

Howard, David F.; Perry, Jay L.; Knox, James C.; Junaedi, Christian

2009-01-01

This paper describes efforts to improve on typical packed beds of sorbent pellets by making use of structured sorbents and alternate bed configurations to improve system efficiency and reliability. The benefits of the alternate configurations include increased structural stability gained by eliminating clay bound zeolite pellets that tend to fluidize and erode, and better thermal control during sorption to increase process efficiency. Test results that demonstrate such improvements are described and presented.

Sulfates and Clays in Columbus Crater, Mars

NASA Image and Video Library

2011-11-21

Sulfates are found overlying clay minerals in sediments within Columbus Crater, a depression that likely hosted a lake in the past in this image based on information from NASA Mars Reconnaissance Orbiter.

CLAYFORM: a FORTRAN 77 computer program apportioning the constituents in the chemical analysis of a clay or other silicate mineral into a structural formula

USGS Publications Warehouse

Bodine, M.W.

1987-01-01

The FORTRAN 77 computer program CLAYFORM apportions the constituents of a conventional chemical analysis of a silicate mineral into a user-selected structure formula. If requested, such as for a clay mineral or other phyllosilicate, the program distributes the structural formula components into appropriate default or user-specified structural sites (tetrahedral, octahedral, interlayer, hydroxyl, and molecular water sites), and for phyllosilicates calculates the layer (tetrahedral, octahedral, and interlayer) charge distribution. The program also creates data files of entered analyses for subsequent reuse. ?? 1987.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ilgen, A. G.; Kukkadapu, R. K.; Dunphy, D. R.

Heterogeneous redox reactions on clay mineral surfaces control mobility and bioavailability of redox-sensitive nutrients and contaminants. Iron (Fe) residing in clay mineral structures can either catalyze or directly participate in redox reactions; however, chemical controls over its reactivity are not fully understood. In our previous work we demonstrated that converting a minor portion of Fe(III) to Fe(II) (partial reduction) in the octahedral sheet of natural Fe-rich clay mineral nontronite (NAu-1) activates its surface, making it redox-active. In this study we produced and characterized synthetic ferric nontronite (SIP), highlighting structural and chemical similarities and differences between this synthetic nontronite and itsmore » natural counterpart NAu-1, and probed whether mineral surface is redox-active by reacting it with arsenic As(III) under oxic and anoxic conditions. We demonstrate that synthetic nontronite SIP undergoes the same activation as natural nontronite NAu-1 following the partial reduction treatment. Similar to NAu-1, SIP oxidized As(III) to As(V) under both oxic (catalytic pathway) and anoxic (direct oxidation) conditions. The similar reactivity trends observed for synthetic nontronite and its natural counterpart make SIP an appropriate analog for laboratory studies. The development of chemically pure analogs for ubiquitous soil minerals will allow for systematic research of the fundamental properties of these minerals.« less

Synthesis and characterization of redox-active ferric nontronite

DOE PAGES

Ilgen, A. G.; Kukkadapu, R. K.; Dunphy, D. R.; ...

2017-07-12

Heterogeneous redox reactions on clay mineral surfaces control mobility and bioavailability of redox-sensitive nutrients and contaminants. Iron (Fe) residing in clay mineral structures can either catalyze or directly participate in redox reactions; but, chemical controls over its reactivity are not fully understood. In our previous work we demonstrated that converting a minor portion of Fe(III) to Fe(II) (partial reduction) in the octahedral sheet of natural Fe-rich clay mineral nontronite (NAu-1) activates its surface, making it redox-active. In this study we produced and characterized synthetic ferric nontronite (SIP), highlighting structural and chemical similarities and differences between this synthetic nontronite and itsmore » natural counterpart NAu-1, and probed whether mineral surface is redox-active by reacting it with arsenic As(III) under oxic and anoxic conditions. Here, we demonstrate that synthetic nontronite SIP undergoes the same activation as natural nontronite NAu-1 following the partial reduction treatment. Similar to NAu-1, SIP oxidized As(III) to As(V) under both oxic (catalytic pathway) and anoxic (direct oxidation) conditions. The similar reactivity trends observed for synthetic nontronite and its natural counterpart make SIP an appropriate analog for laboratory studies. The development of chemically pure analogs for ubiquitous soil minerals will allow for systematic research of the fundamental properties of these minerals.« less

Heterogeneous nucleation of nitric acid trihydrate on clay minerals: relevance to type ia polar stratospheric clouds.

PubMed

Hatch, Courtney D; Gough, Raina V; Toon, Owen B; Tolbert, Margaret A

2008-01-17

Although critical to atmospheric modeling of stratospheric ozone depletion, selective heterogeneous nuclei that promote the formation of Type Ia polar stratospheric clouds (PSCs) are largely unknown. While mineral particles are known to be good ice nuclei, it is currently not clear whether they are also good nuclei for PSCs. In the present study, a high-vacuum chamber equipped with transmission Fourier transform infrared spectroscopy and a quadrupole mass spectrometer was used to study heterogeneous nucleation of nitric acid trihydrate (NAT) on two clay minerals-Na-montmorillonite and kaolinite-as analogs of atmospheric terrestrial and extraterrestrial minerals. The minerals are first coated with a 3:1 supercooled H2O/HNO3 solution prior to the observed nucleation of crystalline NAT. At 220 K, NAT formation was observed at low SNAT values of 12 and 7 on kaolinite and montmorillonite clays, respectively. These are the lowest SNAT values reported in the literature on any substrate. However, NAT nucleation exhibited significant temperature dependence. At lower temperatures, representative of typical polar stratospheric conditions, much higher supersaturations were required before nucleation was observed. Our results suggest that NAT nucleation on mineral particles, not previously treated with sulfuric acid, may not be an important nucleation platform for Type Ia PSCs under normal polar stratospheric conditions.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ilgen, A. G.; Kukkadapu, R. K.; Dunphy, D. R.

Heterogeneous redox reactions on clay mineral surfaces control mobility and bioavailability of redox-sensitive nutrients and contaminants. Iron (Fe) residing in clay mineral structures can either catalyze or directly participate in redox reactions; but, chemical controls over its reactivity are not fully understood. In our previous work we demonstrated that converting a minor portion of Fe(III) to Fe(II) (partial reduction) in the octahedral sheet of natural Fe-rich clay mineral nontronite (NAu-1) activates its surface, making it redox-active. In this study we produced and characterized synthetic ferric nontronite (SIP), highlighting structural and chemical similarities and differences between this synthetic nontronite and itsmore » natural counterpart NAu-1, and probed whether mineral surface is redox-active by reacting it with arsenic As(III) under oxic and anoxic conditions. Here, we demonstrate that synthetic nontronite SIP undergoes the same activation as natural nontronite NAu-1 following the partial reduction treatment. Similar to NAu-1, SIP oxidized As(III) to As(V) under both oxic (catalytic pathway) and anoxic (direct oxidation) conditions. The similar reactivity trends observed for synthetic nontronite and its natural counterpart make SIP an appropriate analog for laboratory studies. The development of chemically pure analogs for ubiquitous soil minerals will allow for systematic research of the fundamental properties of these minerals.« less

The crystal cavities of the New Jersey zeolite region

USGS Publications Warehouse

Schaller, Waldemar Theodore

1932-01-01

The crystal cavities present in the mineral complex of the New Jersey traprock region have long excited the interest of mineralogists. In 1914 Fenner made the first detailed and comprehensive study of these cavities and suggested that babingtonite was the original mineral. Soon after this anhydrite was found occupying parts of some of the cavities at one of the quarries. At this time, too, Wherry concluded that glauberite was the original mineral of some of the cavities because of his studies of similar crystal cavities in Triassic shale at different places.

Activated zeolite--suitable carriers for microorganisms in anaerobic digestion processes?

PubMed

Weiß, S; Lebuhn, M; Andrade, D; Zankel, A; Cardinale, M; Birner-Gruenberger, R; Somitsch, W; Ueberbacher, B J; Guebitz, G M

2013-04-01

Plant cell wall structures represent a barrier in the biodegradation process to produce biogas for combustion and energy production. Consequently, approaches concerning a more efficient de-polymerisation of cellulose and hemicellulose to monomeric sugars are required. Here, we show that natural activated zeolites (i.e. trace metal activated zeolites) represent eminently suitable mineral microhabitats and potential carriers for immobilisation of microorganisms responsible for anaerobic hydrolysis of biopolymers stabilising related bacterial and methanogenic communities. A strategy for comprehensive analysis of immobilised anaerobic populations was developed that includes the visualisation of biofilm formation via scanning electron microscopy and confocal laser scanning microscopy, community and fingerprint analysis as well as enzyme activity and identification analyses. Using SDS polyacrylamide gel electrophoresis, hydrolytical active protein bands were traced by congo red staining. Liquid chromatography/mass spectroscopy revealed cellulolytical endo- and exoglucanase (exocellobiohydrolase) as well as hemicellulolytical xylanase/mannase after proteolytic digestion. Relations to hydrolytic/fermentative zeolite colonisers were obtained by using single-strand conformation polymorphism analysis (SSCP) based on amplification of bacterial and archaeal 16S rRNA fragments. Thereby, dominant colonisers were affiliated to the genera Clostridium, Pseudomonas and Methanoculleus. The specific immobilisation on natural zeolites with functional microbes already colonising naturally during the fermentation offers a strategy to systematically supply the biogas formation process responsive to population dynamics and process requirements.

Atomic force microscopy measurements of bacterial adhesion and biofilm formation onto clay-sized particles

PubMed Central

Huang, Qiaoyun; Wu, Huayong; Cai, Peng; Fein, Jeremy B.; Chen, Wenli

2015-01-01

Bacterial adhesion onto mineral surfaces and subsequent biofilm formation play key roles in aggregate stability, mineral weathering, and the fate of contaminants in soils. However, the mechanisms of bacteria-mineral interactions are not fully understood. Atomic force microscopy (AFM) was used to determine the adhesion forces between bacteria and goethite in water and to gain insight into the nanoscale surface morphology of the bacteria-mineral aggregates and biofilms formed on clay-sized minerals. This study yields direct evidence of a range of different association mechanisms between bacteria and minerals. All strains studied adhered predominantly to the edge surfaces of kaolinite rather than to the basal surfaces. Bacteria rarely formed aggregates with montmorillonite, but were more tightly adsorbed onto goethite surfaces. This study reports the first measured interaction force between bacteria and a clay surface, and the approach curves exhibited jump-in events with attractive forces of 97 ± 34 pN between E. coli and goethite. Bond strengthening between them occurred within 4 s to the maximum adhesion forces and energies of −3.0 ± 0.4 nN and −330 ± 43 aJ (10−18 J), respectively. Under the conditions studied, bacteria tended to form more extensive biofilms on minerals under low rather than high nutrient conditions. PMID:26585552

Experimental alteration of artificial and natural impact melt rock from the Chesapeake Bay impact structure

USGS Publications Warehouse

Declercq, J.; Dypvik, H.; Aagaard, Per; Jahren, J.; Ferrell, R.E.; Horton, J. Wright

2009-01-01

The alteration or transformation of impact melt rock to clay minerals, particularly smectite, has been recognized in several impact structures (e.g., Ries, Chicxulub, Mj??lnir). We studied the experimental alteration of two natural impact melt rocks from suevite clasts that were recovered from drill cores into the Chesapeake Bay impact structure and two synthetic glasses. These experiments were conducted at hydrothermal temperature (265 ??C) in order to reproduce conditions found in meltbearing deposits in the first thousand years after deposition. The experimental results were compared to geochemical modeling (PHREEQC) of the same alteration and to original mineral assemblages in the natural melt rock samples. In the alteration experiments, clay minerals formed on the surfaces of the melt particles and as fine-grained suspended material. Authigenic expanding clay minerals (saponite and Ca-smectite) and vermiculite/chlorite (clinochlore) were identified in addition to analcime. Ferripyrophyllite was formed in three of four experiments. Comparable minerals were predicted in the PHREEQC modeling. A comparison between the phases formed in our experiments and those in the cores suggests that the natural alteration occurred under hydrothermal conditions similar to those reproduced in the experiment. ?? 2009 The Geological Society of America.

Zeolite Formation and Weathering Processes in Dry Valleys of Antartica: Martian Analogs

NASA Technical Reports Server (NTRS)

Gibson, E. K., Jr.; Wentworth, S. J.; McKay, D. S.; Socki, R. A.

2004-01-01

Terrestrial weathering processes in cold-desert climates such as the Dry Valleys of Antarctica may provide an excellent analog to chemical weathering and diagenesis of soils on Mars. Detailed studies of soil development and the chemical and mineralogical alterations occurring within soil columns in Wright Valley, Antarctica show incredible complexity in the upper meter of soil. Previous workers noted the ice-free Dry Valleys are the best terrestrial approximations to contemporary Mars. Images returned from the Pathfinder and Spirit landers show similarities to surfaces observed within the Dry Valleys. Similarities to Mars that exist in these valleys are: mean temperatures always below freezing (-20 C), no rainfall, sparse snowfall-rapidly removed by sublimation, desiccating winds, diurnal freeze-thaw cycles (even during daylight hours), low humidity, oxidative environment, relatively high solar radiation and low magnetic fields . The Dry Valley soils contain irregular distributions and low abundances of soil microorganisms that are somewhat unusual on Earth. Physical processes-such as sand abrasion-are dominant mechanisms of rock weathering in Antarctica. However, chemical weathering is also an important process even in such extreme climates. For example, ionic migration occurs even in frozen soils along liquid films on individual soil particles. It has also been shown that water with liquid-like properties is present in soils at temperatures on the order of approx.-80 C and it has been observed that the percentage of oxidized iron increases with increasing soil age and enrichments in oxidized iron occurs toward the surface. The presence of evaporates is evident and appear similar to "evaporite sites" within the Pathfinder and Spirit sites. Evaporites indicate ionic migration and chemical activity even in the permanently frozen zone. The presence of evaporates indicates that chemical weathering of rocks and possibly soils has been active. Authogenic zeolites have been identified within the soil columns because they are fragile; i.e. they are euhedral, unabraded, and unfractured, strongly suggesting in situ formation. Their presence in Antarctic samples is another indication that diagenic processes are active in cold-desert environments. The presence of zeolites, and other clays along with halites, sulfates, carbonates, and hydrates are to be expected within the soil columns on Mars at the Gusev and Isidis Planitia regions. The presence of such water-bearing minerals beneath the surface supplies one of the requirements to support biological activity on Mars.

An Investigation of the Effects of Deposit Feeding Invertebrates on the Structural Properties of Clay Minerals.

DTIC Science & Technology

1981-07-01

Dennis M. Lavoie of NORDA for chemical analysis of clay minerals with the x-ray energy dispersive spectrometer. We thank Fred Bowles, Peter Fleischer...diffractograi of Nuculana acuta fecal pellet 11 residue (illite experiment). TABLES TABLE 1. X-ray energy dispersive spectrometer chemical 8 analysis for...inontmorillonite experiments. Counts for elements after background counts removed. TABLE 2. X-ray energy dispersive spectroneter chemical analysis 12 for

Mineral-produced high-pressure striae and clay polish: Key evidence for nonballistic transport of ejecta from Ries crater

USGS Publications Warehouse

Chao, E.C.T.

1976-01-01

Recently discovered mineral-produced, deeply incised striae and mirror-like polish on broken surfaces of limestone fragments from the sedimentary ejecta of the Ries impact crater of southern Germany are described. The striae and polish were produced under high confining pressures during high-velocity nonballistic transport of the ejecta mass within the time span of the cratering event (measured in terms of seconds). The striae on these fragments were produced by scouring by small mineral grains embedded in the surrounding clay matrix, and the polish was formed under the same condition, by movements of relatively fragment-free clay against the fragment surfaces. The occurrence of these striae and polish is key evidence for estimating the distribution and determining the relative importance of nonballistic and ballistic transport of ejecta from the shallow Ries stony meteorite impact crater.

Dirt in the Wound: Evaluating the Role of Iron in Antibacterial Minerals

NASA Astrophysics Data System (ADS)

Morrison, K. D.; Williams, L. B.

2013-12-01

The recent discovery of antibacterial clay deposits which are effective in killing antibiotic resistant bacteria may lead to the discovery of mineral based antibacterial mechanisms. These antibacterial clays have been shown to prevent the growth of a broad spectrum of bacteria, including methicillin-resistant Staphylococcus aureus MRSA and extended-spectrum beta lactamase (ESBL) Escherichia coli (antibiotic resistant strains) when tested in vitro. This study investigates the first antibacterial mineral deposit identified in the United States, the Oregon Mineral Technologies (OMT) mine, which formed from the hydrothermal alteration of porphyry andesites. Our hypothesis is that mixed-layered clay minerals containing nano-iron sulfides can release soluble transition metals at low pH which are antibacterial due to the rapid influx and precipitation of intracellular metal-oxides while generating reactive oxygen species (ROS) and damaging bacterial membranes. To test this hypothesis, E. coli (ATCC 25922) was reacted with clay suspensions and clay leachates (solutions equilibrated with clays for 24 hrs). Inductively coupled plasma mass spectrometry (ICP-MS) was used to measure the soluble transition metals that are leaching from the clays. Bioimaging using scanning transmission electron microscopy-electron energy loss spectroscopy (STEM-EELS) and scanning transmission X-ray microscopy (STXM) were used to investigate the precipitation of intracellular mineral particles and redox state of the soluble metals reacting with the bacteria. Reactive oxygen species (ROS) were measured using a spectrophotometric hydrogen peroxide assay (H2O2) assay. Aldehydes were measured using HPLC-UV-Vis (high-performance liquid chromatography-ultraviolet-visible). Antibacterial susceptibility testing and ICP-MS elemental analysis of the leachates reveals that low pH (2.5-3.1) samples containing mM levels of soluble Fe, Al and Ca are antibacterial. All other potential toxins are below the minimum inhibitory concentrations for bactericide. The acidic pH is not the only factor contributing to the antibacterial effect. The intracellular particles observed upon cell death were determined to be Fe-oxides by STEM-EELS. STXM iron maps of single cells indicate that soluble Fe2+ and Fe3+ are adsorbing to the bacterial cell walls. The adsorption of reduced iron to the cell walls of bacteria can result in lipid peroxidation and the concurrent release of toxic aldehydes. Results from the HPLC-UV-Vis aldehyde assay reveal that the antibacterial leachates cause lipid peroxidation and the release of mono-aldehydes at μM levels from bacterial cell walls. The hydrogen peroxide and ferrous/ferric iron assay of the mineral leachates indicates that H2O2 is being generated in the presence of Fe2+, ultimately generating hydroxyl radicals which are toxic to bacterial lipids, proteins and DNA.

Formation and use of coal combustion residues from three types of power plants burning Illinois coals

USGS Publications Warehouse

Demir, I.; Hughes, R.E.; DeMaris, P.J.

2001-01-01

Coal, ash, and limestone samples from a fluidized bed combustion (FBC) plant, a pulverized coal combustion (PC) plant, and a cyclone (CYC) plant in Illinois were analyzed to determine the combustion behavior of mineral matter, and to propose beneficial uses for the power plant ashes. Pyrite and marcasite in coal were converted during combustion to glass, hematite and magnetite. Calcite was converted to lime and anhydrite. The clay minerals were altered to mullite and glass. Quartz was partially altered to glass. Trace elements in coal were partially mobilized during combustion and, as a result, emitted into the atmosphere or adsorbed on fly ash or on hardware on the cool side of the power plants. Overall, the mobilities of 15 trace elements investigated were lower at the FBC plant than at the other plants. Only F and Mn at the FBC plant, F, Hg, and Se at the PC plant and Be, F, Hg, and Se at the CYC plant had over 50% of their concentrations mobilized. Se and Ge could be commercially recovered from some of the combustion ashes. The FBC ashes could be used as acid neutralizing agents in agriculture and waste treatment, and to produce sulfate fertilizers, gypsum wall boards, concrete, and cement. The PC and CYC fly ashes can potentially be used in the production of cement, concrete, ceramics, and zeolites. The PC and CYC bottom ashes could be used in stabilized road bases, as frits in roof shingles, and perhaps in manufacturing amber glass. ?? 2001 Elsevier Science Ltd. All rights reserved.

Unearthing the Antibacterial Mechanism of Medicinal Clay: A Geochemical Approach to Combating Antibiotic Resistance

DOE PAGES

Morrison, Keith D.; Misra, Rajeev; Williams, Lynda B.

2016-01-08

Natural antibacterial clays, when hydrated and applied topically, kill human pathogens including antibiotic resistant strains proliferating worldwide. Only certain clays are bactericidal; those containing soluble reduced metals and expandable clay minerals that absorb cations, providing a capacity for extended metal release and production of toxic hydroxyl radicals. Here we show the critical antibacterial components are soluble Fe 2+ and Al 3+ that synergistically attack multiple cellular systems in pathogens normally growth-limited by Fe supply. This geochemical process is more effective than metal solutions alone and provides an alternative antibacterial strategy to traditional antibiotics. Advanced bioimaging methods and genetic show thatmore » Al 3+ misfolds cell membrane proteins, while Fe 2+ evokes membrane oxidation and enters the cytoplasm inflicting hydroxyl radical attack on intracellular proteins and DNA. The lethal reaction precipitates Fe 3+-oxides as biomolecular damage proceeds. In conclusion, discovery of this bactericidal mechanism demonstrated by natural clays should guide designs of new mineral-based antibacterial agents.« less

Unearthing the Antibacterial Mechanism of Medicinal Clay: A Geochemical Approach to Combating Antibiotic Resistance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morrison, Keith D.; Misra, Rajeev; Williams, Lynda B.

Natural antibacterial clays, when hydrated and applied topically, kill human pathogens including antibiotic resistant strains proliferating worldwide. Only certain clays are bactericidal; those containing soluble reduced metals and expandable clay minerals that absorb cations, providing a capacity for extended metal release and production of toxic hydroxyl radicals. Here we show the critical antibacterial components are soluble Fe 2+ and Al 3+ that synergistically attack multiple cellular systems in pathogens normally growth-limited by Fe supply. This geochemical process is more effective than metal solutions alone and provides an alternative antibacterial strategy to traditional antibiotics. Advanced bioimaging methods and genetic show thatmore » Al 3+ misfolds cell membrane proteins, while Fe 2+ evokes membrane oxidation and enters the cytoplasm inflicting hydroxyl radical attack on intracellular proteins and DNA. The lethal reaction precipitates Fe 3+-oxides as biomolecular damage proceeds. In conclusion, discovery of this bactericidal mechanism demonstrated by natural clays should guide designs of new mineral-based antibacterial agents.« less

Unearthing the Antibacterial Mechanism of Medicinal Clay: A Geochemical Approach to Combating Antibiotic Resistance

PubMed Central

Morrison, Keith D.; Misra, Rajeev; Williams, Lynda B.

2016-01-01

Natural antibacterial clays, when hydrated and applied topically, kill human pathogens including antibiotic resistant strains proliferating worldwide. Only certain clays are bactericidal; those containing soluble reduced metals and expandable clay minerals that absorb cations, providing a capacity for extended metal release and production of toxic hydroxyl radicals. Here we show the critical antibacterial components are soluble Fe2+ and Al3+ that synergistically attack multiple cellular systems in pathogens normally growth-limited by Fe supply. This geochemical process is more effective than metal solutions alone and provides an alternative antibacterial strategy to traditional antibiotics. Advanced bioimaging methods and genetic show that Al3+ misfolds cell membrane proteins, while Fe2+ evokes membrane oxidation and enters the cytoplasm inflicting hydroxyl radical attack on intracellular proteins and DNA. The lethal reaction precipitates Fe3+-oxides as biomolecular damage proceeds. Discovery of this bactericidal mechanism demonstrated by natural clays should guide designs of new mineral-based antibacterial agents. PMID:26743034

Influence of Clay Content, Mineralogy and Fabric On Radar Frequency Response of Aquifer Materials

NASA Astrophysics Data System (ADS)

West, L. J.; Handley, K.

High frequency electromagnetic methods such as ground penetrating radar (GPR) and time domain reflectometry (TDR) are widely employed to measure water saturation in the vadose zone and water filled porosity in the saturated zone. However, previous work has shown that radar frequency dielectric properties are strongly influenced by clay as well as by water content. They have also shown that that the dielectric response of clay minerals is strongly frequency dependent, and that even a small proportion of clay such as that present in many sandstone aquifers can have a large effect at typi- cal GPR frequencies (around 100MHz). Hence accurate water content/porosity deter- mination requires clay type and content to be taken into account. Reported here are dielectric measurements on clay-sand mixtures, aimed at investigating the influence of clay mineralogy, particle shape, and the geometrical arrangement of the mixture constituents on GPR and TDR response. Dielectric permittivity (at 50-1000MHz) was measured for mixtures of Ottawa Sand and various clay minerals or clay size quartz rock flour, using a specially constructed dielectric cell. Both homogeneous and layered mixtures were tested. The influence of pore water salinity, clay type, and particle arrangement on the dielectric response is interpreted in terms of dielectric dispersion mechanisms. The appropriateness of var- ious dielectric mixing rules such as the Complex Refractive Index Method (CRIM) for determination of water content or porosity from field GPR and TDR data are dis- cussed.

Landslide: Mineralogical and Physical Investigation

NASA Astrophysics Data System (ADS)

Tudor, Viluș; Grozav, Adia; Rogobete, Gheorghe

2017-10-01

In order to construct a road bed foundation, if land has moved, on an area with old landslides, there is a high chance of it moving again. The investigation was made in a region with hilly relief, in which the parent materials of soils are argillaceous marls of Pliocene age. Because the slope is scarped and the versant has been cut, the soil mass slide favoured of the particle-size distribution dominated by heavy clay. With a reiteratedly percolative moisture regime, the soil material is saturated in water fora long period (700-800 mm precipitation/year), and that can increase the slope mass, thereby increasing the driving forces. In a soil profile situated on the top of the hill, with landslide for about 40 m length of the road, disturbed and undisturbed soil samples were analysed physic-chemical and mineralogical. For the heavy and light minerals from the sand fraction a polarized light analyser is used, and for clay minerals X-ray, differential thermal and infrared absorption method are used. The particle-size distribution in the soil profile is dominated by the clay fraction, which reached 53.2% in the ABt horizon and 63.0% in the Bt horizon (67-93 cm depth). The structure of the light minerals, consists of quartz (41-58%); feldspar (10.16-18.10%); muscovite (14.10-26.04). The heavy minerals are oxides (2.61-15.26%), hornblende (0.58-2.87%) and biotite (0.51-2.68%). It must be mentioned the presence of the metamorphic minerals, with the source of the Poiana Rusca mountains. These minerals are epidote (1.01-1.86%), disthene (0.70-1.86%), staurolite (0.73-2.46%) and sillimanite (0.35-0.45%). The clay minerals, inherited from the parent material or formed during the soil-forming process are dominated by smectite, which represent (71-85%) from the total clay minerals, illite 10-21%, and Kaolinite, 4-12%. Rheological properties, like plastic index (53.8%), activity index (1.01%) and consistency index (0.99-1.00%) show that the shrinkage - swelling processes are active, and provoke landslide. We propose some technical measures for decreasing the driving force and increasing the resisting forces on the slope, such as: drainage net with track ditch and inspection chamber, driven pile a 10 m depth, and so on.

Disentangling controls on mineral-stabilized soil organic matter using a slurry incubation

NASA Astrophysics Data System (ADS)

Lavallee, J. M.; Cotrufo, M. F.; Paul, E. A.; Conant, R. T.

2014-12-01

Mineral-stabilized organic matter (OM) is the largest and oldest pool of soil carbon and nitrogen. Mineral stabilization limits OM availability to soil microbes, preventing its decomposition and prolonging its turnover. Thus, understanding controls on the decomposition of mineral-stabilized OM is key to understanding soil carbon and nitrogen dynamics. The very slow turnover of mineral-stabilized OM makes it challenging to study in a typical incubation, and as a result, many potential controls (temperature, OM chemistry, and mineralogy) on its turnover remain unclear. We aimed to better understand controls on decomposition of mineral-stabilized OM by employing a slurry incubation technique, which speeds up microbial processing of OM by maximizing OM accessibility to microbes. In a slurry incubation, we expect that any OM that is not stabilized on mineral surfaces will be available for decomposition and will be converted to CO2. Using this technique, we studied the interactive effects of incubation temperature, plant material type (aboveground vs. belowground), and soil fraction (silt vs. clay) on CO2 efflux and OM stabilization. We separated silt-sized and clay-sized fractions from an agricultural soil, added aboveground or belowground plant material to each, and incubated them at 15°C, 25°C and 35°C. The added plant material was isotopically labeled (13C and 15N), which allowed us to trace it through the system and distinguish between the responses of the new (derived from the plant material) and old (derived from what was already present in the silt and clay) OM to warming. We measured CO2 efflux and 13CO2 efflux throughout the incubation. We performed one short-term harvest at day 6 and one final harvest at day 60. Initial results show higher cumulative CO2 efflux at warmer temperatures regardless of plant material type or soil fraction. A larger fraction of that CO2 came from OM that was initially present in the silt and clay, rather than from the plant material that we added, which suggests faster turnover of that "old" OM at warmer temperatures. We will present CO2 efflux data in addition to total [C] and [N] and the isotopic ratios of 13C and 15N in the silt and clay at each harvest to explain how the interactions between warming, plant material type and soil fraction affect turnover of mineral stabilized OM.

One-pot synthesis of hierarchical FeZSM-5 zeolites from natural aluminosilicates for selective catalytic reduction of NO by NH3

PubMed Central

Yue, Yuanyuan; Liu, Haiyan; Yuan, Pei; Yu, Chengzhong; Bao, Xiaojun

2015-01-01

Iron-modified ZSM-5 zeolites (FeZSM-5s) have been considered to be a promising catalyst system to reduce nitrogen oxide emissions, one of the most important global environmental issues, but their synthesis faces enormous economic and environmental challenges. Herein we report a cheap and green strategy to fabricate hierarchical FeZSM-5 zeolites from natural aluminosilicate minerals via a nanoscale depolymerization-reorganization method. Our strategy is featured by neither using any aluminum-, silicon-, or iron-containing inorganic chemical nor involving any mesoscale template and any post-synthetic modification. Compared with the conventional FeZSM-5 synthesized from inorganic chemicals with the similar Fe content, the resulting hierarchical FeZSM-5 with highly-dispersed iron species showed superior catalytic activity in the selective catalytic reduction of NO by NH3. PMID:25791958

Clay minerals trap hydrogen in the Earth's crust: Evidence from the Cigar Lake uranium deposit, Athabasca

NASA Astrophysics Data System (ADS)

Truche, Laurent; Joubert, Gilles; Dargent, Maxime; Martz, Pierre; Cathelineau, Michel; Rigaudier, Thomas; Quirt, David

2018-07-01

Hydrogen (H2)-rich fluids are observed in a wide variety of geologic settings including gas seeps in serpentinized ultramafic rocks, sub-seafloor hydrothermal vents, fracture networks in crystalline rocks from continental and oceanic crust, and volcanic gases. Natural hydrogen sources can sustain deep microbial ecosystems, induce abiotic hydrocarbons synthesis and trigger the formation of prebiotic organic compounds. However, due to its extreme mobility and small size, hydrogen is not easily trapped in the crust. If not rapidly consumed by redox reactions mediated by bacteria or suitable mineral catalysts it diffuses through the rocks and migrates toward the surface. Therefore, H2 is not supposed to accumulate in the crust. We challenge this view by demonstrating that significant amount of H2 may be adsorbed by clay minerals and remain trapped beneath the surface. Here, we report for the first time H2 content in clay-rich rocks, mainly composed of illite, chlorite, and kaolinite from the Cigar Lake uranium ore deposit (northern Saskatchewan, Canada). Thermal desorption measurements reveal that H2 is enriched up to 500 ppm (i.e. 0.25 mol kg-1 of rock) in these water-saturated rocks having a very low total organic content (<0.5 wt%). Such hydrogen uptake is comparable and even exceeds adsorbed methane capacities reported elsewhere for pure clay minerals or shales. Sudoite (Al-Mg di-trioctahedral chlorite) is probably the main mineral responsible for H2 adsorption in the present case. The presence of multiple binding sites in interlinked nanopores between crystal layers of illite-chlorite particles offers the ideal conditions for hydrogen sorption. We demonstrate that 4 to 17% of H2 produced by water radiolysis over the 1.4-Ga-lifetime of the Cigar Lake uranium ore deposit has been trapped in the surrounding clay alteration haloes. As a result, sorption processes on layered silicates must not be overlooked as they may exert an important control on the fate and mobility of H2 in the crust. Furthermore, the high capacity of clay minerals to sorb molecular hydrogen may also open up new opportunities for exploration of unexpected energy resources and for H2 storage based on geo-inspired materials.

Controlling weathering and erosion intensity on the southern slope of the Central Himalaya by the Indian summer monsoon during the last glacial

NASA Astrophysics Data System (ADS)

Kuwahara, Yoshihiro; Masudome, Yukiko; Paudel, Mukunda Raj; Fujii, Rie; Hayashi, Tatsuya; Mampuku, Mami; Sakai, Harutaka

2010-03-01

This paper reports the results of clay mineral analysis (the amount of clay fraction, clay mineral assemblages, illite crystallinity) of samples collected from a drilled core (Rabibhawan (RB) core) located in the west-central part of the Kathmandu Basin on the southern slope of the Central Himalaya. The amount of clay fraction in the core sediments between 12 m and 45 m depth (corresponding to ca. 17-76 ka), which belong to the Kalimati Formation, is variable and shows three clay-poor zones (19-31 ka, 44-51 ka, and 66-75 ka). The variations correspond with those of illite crystallinity index (Lanson index (LI) and modified Lanson index (MLI)) and kaolinite/illite ratio as well as the fossil pollen and diatom records reported by previous workers. These data reveal the following transformations occurring during the weathering process in this area: micas(mainlymuscovite)→illite(→illite-smectitemixedlayermineral(R=1))→kaolinite The sedimentation rate (~ 50 cm/kyr) of clay-poor zones that correspond to dry climate intervals is only half that of clay-rich zones (~ 120 cm/kyr) that correspond to wet climate intervals, indicating weakened chemical weathering and erosion and low suspended discharge during dry climate intervals. The clay-poor zones commonly show unique laminite beds with very fine, authigenic calcite, which was probably precipitated under calm and high calcite concentration conditions caused by low precipitation and run-off. The variations between dry and wet conditions in this area as deduced from clay minerals appear to follow the Indian Summer Monsoon Index (ISMI) (30°N-30°S, 1 July) and northern hemisphere summer insolation (NHSI) signals (30°N) at 1 July, especially during the dry climate zones, whereas the wet maxima of the wet climate zones somewhat deviate from the strongest NHSI. On the other hand, the dry-wet records lead markedly the SPECMAP stack (by about 5000 years). These results suggest that the Indian summer monsoon precipitation was strongly controlled by the NHSI or summer insolation difference between the Himalayan-Tibetan Plateau and the subtropical Indian Ocean, showing a major fluctuation on the 23,000 years precessional cycle, and that it was not driven by changes in high-latitude ice volume, although the records of clay mineral indices during the wet intervals leave a question that other factors, in addition to insolation forcing, may play important roles in weathering, erosion, and sedimentation processes.

Heteroagglomeration of zinc oxide nanoparticles with clay mineral modulates the bioavailability and toxicity of nanoparticle in Tetrahymena pyriformis.

PubMed

Gupta, Govind Sharan; Senapati, Violet Aileen; Dhawan, Alok; Shanker, Rishi

2017-06-01

The extensive use of zinc oxide nanoparticles (ZnO NPs) in cosmetics, sunscreens and healthcare products increases their release in the aquatic environment. The present study explored the possible interaction of ZnO NPs with montmorillonite clay minerals in aqueous conditions. An addition of ZnO NPs on clay suspension significantly (p<0.05) increases the hydrodymic size of clay particles from 1652±90nm to 2158±13nm due to heteroagglomeration. The electrokinetic measurements showed a significant (p<0.05) difference in the electrophoretic mobilities of bare (-1.80±0.03μmcm/Vs) and ZnO NPs-clay association (-1.37±0.03μmcm/Vs) that results to the electrostatic interaction between ZnO NPs and clay particles. The attenuated total reflectance Fourier transform infrared spectroscopy analysis of ZnO NPs-clay association demonstrated the binding of ZnO NPs with the Si-O-Al region on the edges of clay particles. The increase in size of ZnO NPs-clay heteroagglomerates further leads to their sedimentation at 24h. Although, the stability of ZnO NPs in the clay suspension was decreased due to heteroagglomeration, but the bioavailability and toxicity of ZnO NPs-clay heteroagglomerates in Tetrahymena pyriformis was enhanced. These observations provide an evidence on possible mechanisms available in natural environment that can facilitate nanoparticles entry into the organisms present in lower trophic levels of the food web. Copyright © 2017 Elsevier Inc. All rights reserved.

Near-infrared reflectance spectra of mixtures of kaolin-group minerals: Use in clay mineral studies

USGS Publications Warehouse

Crowley, James K.; Vergo, Norma

1988-01-01

Near-infrared (NIR) reflectance spectra for mixtures of ordered kaolinite and ordered dickite have been found to simulate the spectral response of disordered kaolinite. The amount of octahedral vacancy disorder in nine disordered kaolinite samples was estimated by comparing the sample spectra to the spectra of reference mixtures. The resulting estimates are consistent with previously published estimates of vacancy disorder for similar kaolin minerals that were modeled from calculated X-ray diffraction patterns. The ordered kaolinite and dickite samples used in the reference mixtures were carefully selected to avoid undesirable particle size effects that could bias the spectral results.NIR spectra were also recorded for laboratory mixtures of ordered kaolinite and halloysite to assess whether the spectra could be potentially useful for determining mineral proportions in natural physical mixtures of these two clays. Although the kaolinite-halloysite proportions could only be roughly estimated from the mixture spectra, the halloysite component was evident even when halloysite was present in only minor amounts. A similar approach using NIR spectra for laboratory mixtures may have applications in other studies of natural clay mixtures.

Unraveling the Diversity of Early Aqueous Environments and Climate on Mars Through the Phyllosilicate Record

NASA Technical Reports Server (NTRS)

Bishop, J. L.; Baker, L. L.; Fairén, A. G.; Gross, C.; Velbel, M. A.; Rampe, E. B.; Michalski, J. R.

2017-01-01

Were Martian phyllosilicates formed on the surface or subsurface? Was early Mars warm or cold? How long was liquid water present on the surface of Mars? These are some of the many open questions about our neighboring planet. We propose that the mineralogy of the clay-bearing outcrops on Mars can help address these questions. Abundant phyllosilicates and aqueous minerals are observed nearly everywhere we can see the ancient rocks on Mars. Most bountiful among these is Fe/Mg-smectite. In this study we evaluate the nature and stratigraphy of clay outcrops observed on Mars and the presence of mixtures of other clays or other minerals with the ubiquitous Fe/Mg-smectite.

Clay mineralogy and its palaeoclimatic significance in the Luochuan loess-palaeosols over ˜1.3 Ma, Shaanxi, northwestern China

NASA Astrophysics Data System (ADS)

Won, Changdok; Hong, Hanlie; Cheng, Feng; Fang, Qian; Wang, Chaowen; Zhao, Lulu; Churchman, Gordon Jock

2018-03-01

To understand climate changes recorded in the Luochuan loess-palaeosols, Shaanxi province, northwestern China, clay mineralogy was studied using X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), and scanning electron microscopy (SEM) methods. XRD results show that clay mineral compositions in the Luochuan loess-palaeosols are dominantly illite, with minor chlorite, kaolinite, smectite, and illite-smectite mixed-layer clays (I/S). Illite is the most abundant species in the sediments, with a content of 61%-83%. The content of chlorite ranges from 5%-22%, and the content of kaolinite ranges from 5%-19%. Smectite (or I/S) occurs discontinuously along the loess profile, with a content of 0-8%. The Kübler index of illite (IC) ranges from 0.255°-0.491°, and the illite chemical index (ICI) ranges from 0.294-0.394. The CIA values of the loesspalaeosols are 61.9-69.02, and the R3+/(R3+ + R2+ + M+) values are 0.508-0.589. HRTEM observations show that transformation of illite to illite-smectite has occurred in both the loess and palaeosol, suggesting that the Luochuan loess-palaeosols have experienced a certain degree of chemical weathering. The Luochuan loess-palaeosols have the same clay mineral assemblage along the profile. However, the relative contents of clay mineral species, CIA, ICI, and IC values fluctuate frequently along the profile, and all these parameters display a similar trend. Moreover, climate changes suggested by the clay index are consistent with variations in the deep-sea δ18O records and the magnetic susceptibility value, and thus, climate changes in the Luochuan region have been controlled by global climate change.

Clay mineral assemblages of terrestrial records (Xining Basin, China) during the Eocene-Oligocene climate Transition (EOT) and its environmental implications

NASA Astrophysics Data System (ADS)

Zhang, C.; Guo, Z.

2013-12-01

The Eocene-Oligocene Transition (EOT) between ~34.0 and 33.5 million years ago, where global climate cooled from 'greenhouse' to 'icehouse' at ~33.5 Ma ago, is one of the great events during Cenozoic climate deterioration. In contrast to the marine records of the EOT, significantly less research has focused on the continental climate change during this time, particularly in inner Asia. We present a comprehensive study of the upper Eocene to lower Oligocene succession with regular alternations of laterally continuous gypsum/gypsiferous layers and red mudstone beds in Tashan section of Xining Basin, which is located at the northeastern margin of the Tibetan Plateau. Clay minerals, which were extracted from this succession, were analyzed qualitatively and semi-quantitatively by using X-ray differaction (XRD). Base on detailed magnetostratigraphic time control, clay mineral compositions of this succession (33.1-35.5 Ma) are compared with open ocean marine records and Northern Hemisphere continental records to understand the process and characteristics of Asian climate change before, during and after EOT. Our results indicate that illite is the dominant clay mineral with less chlorite and variable smectite. Multi-parameter evidence suggests that the source areas of detrital inputs in Tashan have not changed and climate is the main control for the composition of the clay fraction. The characteristics of clay mineral concentrations suggest warm and humid fluctuations with cold and dry conditions and intense of seasonality during ~35.5-34.0 Ma in inner Asian. This changed to cold and dry condition at ~34 Ma and remained so from ~34-33.1 Ma. The comparisons between continental and marine records indicate that the climate changes experienced in the Xining basin region are more consistent with Northern Hemisphere rather than open oceans records. This indicates that paleoclimate changes for inner Asian before, during and after EOT was not controlled by Antarctic ice growth, but may be due to atmospheric cooling linked to the existence and expansion of Northern Hemisphere glaciation.

DEVELOPMENT OF NONCARBON SORBENTS FOR HG0 REMOVAL FROM COAL-FIRED POWER PLANTS

EPA Science Inventory

Noncarbon materials or mineral oxides (silica gel, alumina, molecular sieves, zeolites, and montmorillonite) were modified with various functional groups, such as amine, amide, thiol, and urea; and active additives, such as elemental sulfur, sodium sulfide, and sodium polysulfide...

Shallow Water Propagation

DTIC Science & Technology

2013-09-30

HPMM. For these minerals, kaolinite and smectite , the corresponding shear speed estimates are 13 m/s and 0.25 m/s. The third and fourth columns of...representative value for each parameter in two clay minerals, kaolinite and smectite , which are the most common types in marine mud. These values produce...13 m/s for kaolinite and 0.25 m/s for smectite . The third column shows typical ranges of values for h, L, and χ in the two clay types. The fourth

Behavior of adsorbed Poly-A onto sodium montmorillonite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Palomino-Aquino, Nayeli; Negrón-Mendoza, Alicia, E-mail: negron@nucleares.unam.mx

2015-07-23

The adsorption of Poly-A (a polynucleotide consisting of adenine, ribose and a phosphate group), onto a clay mineral, was studied to investigate the extent of adsorption, the site of binding, and the capacity of the clay to protect Poly-A, while it is adsorbed onto the clay, from external sources of energy. The results showed that Poly-A presented a high percentage of adsorption at the edges of the clay and that the survival of the polynucleotide was superior to irradiating the polymer in the absence of the clay.

25 CFR 212.3 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-04-01

..., cinders, granite, building stone, limestone, clay, silt, or any other energy or non-energy mineral... treatment of minerals; Provided, when sand, gravel, pumice, cinders, granite, building stone, limestone...

25 CFR 212.3 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-04-01

..., cinders, granite, building stone, limestone, clay, silt, or any other energy or non-energy mineral... treatment of minerals; Provided, when sand, gravel, pumice, cinders, granite, building stone, limestone...

Evidence for Smectite Clays from MSL SAM Analyses of Mudstone at Yellowknife Bay, Gale Crater, Mars

NASA Technical Reports Server (NTRS)

McAdam, Amy; Franz, Heather; Mahaffy, Paul R.; Eigenbrode, Jennifer L.; Stern, Jennifer C.; Brunner, Anna; Archer, Paul Douglas; Ming, Douglas W.; Morris, Richard V.; Atreya, Sushil K.

2013-01-01

Drilled samples of mudstone from the Sheepbed unit at Yellowknife Bay were analyzed by MSL instruments including the Sample Analysis at Mars (SAM) and Chemistry and Mineralogy (CheMin) instruments in MSL's Analytical Laboratory. CheMin analyses revealed the first in situ X-ray diffraction based evidence of clay minerals on Mars, which are likely trioctahedral smectites (e.g., saponite) and comprise approx 20% of the mudstone sample (e.g., Bristow et al., this meeting). SAM analyses, which heated the mudstone samples to 1000 C and monitored volatiles evolved to perform in situ evolved gas analysis mass spectrometry (EGA-MS), resulted in a H2O trace exhibiting a wide evolution at temperatures < 500 C, and an evolution peak at higher temperatures near approx 750 C. The low temperature H2O evolution has many potential contributors, including adsorbed H2O, smectite interlayer H2O, and structural H2O/OH from bassanite and akaganeite (identified by CheMin) and H2O/OH from amorphous phases in the sample. The high temperature H2O is consistent with the evolution of H2O from the dehydroxylation of the smectite clay mineral. Comparison to EGA-MS data collected under SAM-like conditions on a variety of clay mineral reference materials indicate that a trioctahedral smectite, such as saponite, is most consistent with the high temperature H2O evolution observed. There may also be SAM EGA-MS evidence for a small high temperature H2O evolution from scoop samples from the Yellowknife Bay Rocknest sand shadow bedform. As in the mudstone samples, this evolution may indicate the detection of smectite clays, and the idea that minor clays may be present in Rocknest materials that could be expected to be at least partially derived from local sources is reasonable. But, because smectite clays were not definitively observed in CheMin analyses of Rocknest materials, they must be present at much lower abundances than the approx 20% observed in the mudstone samples. This potential detection underscores the complementary nature of the MSL CheMin and SAM instruments for investigations of martian sample mineralogy. Information on the nature of Yellowknife Bay clay minerals may also be available from the detection of H2 evolved during SAM EGA-MS at high temperature. A likely source of at least some of this H2 is H2O evolved from the smectite clays at high temperature, and it is possible these evolutions can be used in a similar fashion to high temperature H2O releases to provide constraints on the clay minerals in a sample. In addition, the D/H of this high temperature H2, as well as the H2O, can be derived from SAM MS and Tunable Laser Spectrometer (TLS) data, respectively. These D/H values may help to inform the provenance of high and low temperature water evolved from martian samples

Influence of clay minerals on curcumin properties: Stability and singlet oxygen generation

NASA Astrophysics Data System (ADS)

Gonçalves, Joyce L. S.; Valandro, Silvano R.; Poli, Alessandra L.; Schmitt, Carla C.

2017-09-01

Curcumin (CUR) has showed promising photophysical properties regarding to biological and chemical sciences. However, the main barrier for those applications are their low solubility and stability in aqueous solution. The effects of two different clay minerals, the montmorillonite (SWy-2) and the Laponite RD (Lap) nanoclay, on the stabilization of Curcumin were investigated. Their effects were compared with two well-established environments (acidic and neutral aqueous media). CUR/clay hybrids were prepared using a simple and fast method, where CUR solution was added into clay suspensions, to obtain well dispersed hybrids in water. The degradation process of CUR and CUR/clays hybrids was investigated using UV-Vis spectroscopic. For both studied hybrids, the CUR degradation process was suppressed by the presence of the clay particles. Furthermore, the Lap showed a great stabilization effect than SWy-2. This behavior was due to the smaller particle size and higher exfoliation ability of Lap, providing a large surface for CUR adsorption compared to SWy-2. The degradation process of CUR solutions and CUR/clay hybrids was also studied in the presence of light. CUR photodegradation process was faster not only in the aqueous solution but also in the clay suspension compared to those studied in the dark. The presence of clay particles accelerated the photodegradation of CUR due to the products formation in the reactions between CUR and oxygen radicals. Our results showed that the singlet oxygen quantum yield (ΦΔ) of CUR were about 59% higher in the clay suspensions than CUR in aqueous solution. Therefore, the formation of CUR/clay hybrids, in particularly with Lap, suppressed the degradation in absence light of CUR and increased the singlet oxygen generation, which makes this hybrids of CUR/clay a promising material to enlarge the application of CUR in the biological sciences.

Mineral carbonation of gaseous carbon dioxide using a clay-hosted cation exchange reaction.

PubMed

Kang, Il-Mo; Roh, Ki-Min

2013-01-01

The mineral carbonation method is still a challenge in practical application owing to: (1) slow reaction kinetics, (2) high reaction temperature, and (3) continuous mineral consumption. These constraints stem from the mode of supplying alkaline earth metals through mineral acidification and dissolution. Here, we attempt to mineralize gaseous carbon dioxide into calcium carbonate, using a cation exchange reaction of vermiculite (a species of expandable clay minerals). The mineralization is operated by draining NaCI solution through vermiculite powders and continuously dropping into the pool of NaOH solution with CO2 gas injected. The mineralization temperature is regulated here at 293 and 333 K for 15 min. As a result of characterization, using an X-ray powder diffractometer and a scanning electron microscopy, two types of pure CaCO3 polymorphs (vaterite and calcite) are identified as main reaction products. Their abundance and morphology are heavily dependent on the mineralization temperature. Noticeably, spindle-shaped vaterite, which is quite different from a typical vaterite morphology (polycrystalline spherulite), forms predominantly at 333 K (approximately 98 wt%).

Acyl silicates and acyl aluminates as activated intermediates in peptide formation on clays

NASA Technical Reports Server (NTRS)

White, D. H.; Kennedy, R. M.; Macklin, J.

1984-01-01

Glycine reacts with heating on dried clays and other minerals to give peptides in much better yield than in the absence of mineral. This reaction was proposed to occur by way of an activated intermediate such as an acyl silicate or acyl aluminate analogous to acyl phosphates involved in several biochemical reactions including peptide bond synthesis. The proposed mechanism has been confirmed by trapping the intermediate, as well as by direct spectroscopic observation of a related intermediate. The reaction of amino acids on periodically dried mineral surfaces represents a widespead, geologically realistic setting for prebiotic peptide formation via in situ activation.

Study on the Particle Size Distribution Nano-Particles of Mining Minerals on Whiteness of Triaxial Body

NASA Astrophysics Data System (ADS)

Mathur, Ravi; Soni, Aditi

White wares produced worldwide represent the foundation of much of the ceramic industry; Porcelain bodies fabricated from triaxial mixtures of clay, quartz and feldspar with different size and amounts of nano particles were investigated. Although the purity of raw materials has a strong effect on the colour of the fired bodies, the particle size of raw materials also effect the whiteness The raw material mining minerals china Clay, Feldspar, quarts were prepared of various sized nano particles contains 10.60 -20.22%, 56.84- 70.80 % and 34.87-50.76 % of 100nm respectively. The fired bodies of raw mining minerals and triaxial bodies were subjected to colour measurement. The differences in whiteness were compared and discussed. The studies so far carried out is upto 400 mesh size while the present study has included up to 100nm particle size. A statistical correlation between whiteness of feldspar and triaxial body was also carried out. The correlation between china clay and triaxial body are 0.53, 0.57 and 0.66 for china clay similarly correlation for feldspar is 0.49, 0.73 and 0.83 for triaxial body it are 0.97, 0.84 and 0.75 for A1, A2 and A3 samples. Correlation between china clay and feldspar with triaxial body are 0.79 and 0.92 respectively.

Eridania Basin: An ancient paleolake floor as the next landing site for the Mars 2020 rover

NASA Astrophysics Data System (ADS)

Pajola, Maurizio; Rossato, Sandro; Carter, John; Baratti, Emanuele; Pozzobon, Riccardo; Erculiani, Marco Sergio; Coradini, Marcello; McBride, Karen

2016-09-01

The search for traces of past Martian life is directly connected to ancient paleolakes, where ponding water or low-energy water fluxes were present for long time intervals. The Eridania paleolakes system, located along the 180° meridian, is one of the largest lacustrine environments that were once present on Mars. Morphological features suggest that it was constituted by connected depressions filled by water to maximum depths of ∼2400 m and a volume of at least 562,000 km3. We focused our attention on the northern side of the Eridania Basin, where high-albedo, uneven patches of material characterized by the absence of dust are present. Based on OMEGA and CRISM orbital imaging spectroscopy data, a large clay-bearing unit has been identified there. In particular, a set of aqueous minerals in present in the stratigraphy, being visible through erosional windows in the first several tens of meters of the sedimentary sequence. Below this capping unit, a thin Al-rich clay stratum attributable to Al-smectite and/or kaolins is present. This overlies a Fe-rich clay stratum, attributable to the nontronite smectite. At the base of the mineralogic sequence a stratum that could be either a zeolite or more likely a hydrated sulfate is present. In addition, small deposits of alunite (a rare phase on Mars), and jarosite are here found at several locations. Such stratigraphy is interpreted as originating from a surface weathering process similar to terrestrial abiotic pedogenesis; nonetheless, possible exobiologic processes can be also invoked to explain it. NASA's Spirit rover landed on Gusev crater in 2004, near the mouth of the Ma'adim Vallis, which connects this crater with the considered paleolakes system. The Eridania site provides the unique opportunity to complete the measurements obtained in Gusev crater, while investigating the exposed mineralogical sequence in its depositionary setting. In addition, the extremely favorable landing parameters, such as elevation, slope, roughness, rock distribution, thermal inertia and dust coverage, support this location as a possible landing site for the NASA Mars 2020 rover.

Suppression of humoral immune responses by 2,3,7,8-tetrachlorodibenzo-p-dioxin intercalated in smectite clay.

PubMed

Boyd, Stephen A; Johnston, Cliff T; Pinnavaia, Thomas J; Kaminski, Norbert E; Teppen, Brian J; Li, Hui; Khan, Bushra; Crawford, Robert B; Kovalova, Natalia; Kim, Seong-Su; Shao, Hua; Gu, Cheng; Kaplan, Barbara L F

2011-12-01

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a highly toxic environmental contaminant found in soils and sediments. Because of its exceptionally low water solubility, this compound exists predominantly in the sorbed state in natural environments. Clay minerals, especially expandable smectite clays, are one of the major component geosorbents in soils and sediments that can function as an effective adsorbent for environmental dioxins, including TCDD. In this study, TCDD was intercalated in the smectite clay saponite by an incipient wetness method. The primary goal of this study was to intercalate TCDD in natural K-saponite clay and evaluate its immunotoxic effects in vivo. The relative bioavailability of TCDD was evaluated by comparing the metabolic activity of TCDD administered in the adsorbed state as an intercalate in saponite and freely dissolved in corn oil. This comparison revealed nearly identical TCDD-induced suppression of humoral immunity, a well-established and sensitive sequela, in a mammalian (mouse) model. This result suggests that TCDD adsorbed by clays is likely to be available for biouptake and biodistribution in mammals, consistent with previous observations of TCDD in livestock exposed to dioxin-contaminated ball clays that were used as feed additives. Adsorption of TCDD by clay minerals does not appear to mitigate risk associated with TCDD exposure substantially. Copyright © 2011 SETAC.

Molecular Modeling of the Binding Structures in the Interlayer Adsorption of a Tetracycline Antibiotic by Smectite Clays

NASA Astrophysics Data System (ADS)

Aristilde, L.

2009-12-01

A controlling factor in the fate of antibiotics in the environment is their sequestration in soil particles including clay minerals. Of special interest is the interlayer adsorption by smectite clays, which has been shown to influence both the bioavailability and persistence of antibiotics in the soil environment. However, the interlayer structures of the bound antibiotics, essential to an accurate understanding of the adsorption mechanisms, are not well understood. Molecular simulations of oxytetracycline (OTC) with a model montmorillonite (MONT) clay were performed to gain insights into these structures for tetracycline antibiotics. Monte Carlo simulations were used for explorations of the clay layer spacing required for the adsorption of the antibiotic under different hydration states of the clay interlayer; these preliminary results were validated with previous X-ray diffraction patterns obtained following sorption experiments of OTC with MONT. Molecular dynamics relaxation simulations were performed subsequently in order to obtain geometry-optimized structures of the binding conformations of the intercalated antibiotic in the model MONT layers. This study contributes to a mechanistic understanding of the factors controlling the interlayer adsorption of the tetracycline antibiotics by the expandable smectite clay minerals. Figure 1. Optimized Monte Carlo simulation cell of OTC in the interlayer of MONT: perspective side view (top) and bottom view (bottom).

Role of interlayer hydration in lincomycin sorption by smectite clays.

PubMed

Wang, Cuiping; Ding, Yunjie; Teppen, Brian J; Boyd, Stephen A; Song, Cunyi; Li, Hui

2009-08-15

Lincomycin, an antibiotic widely administered as a veterinary medicine, is frequently detected in water. Little is known about the soil-water distribution of lincomycin despite the fact that this is a major determinant of its environmental fate and potential for exposure. Cation exchange was found to be the primary mechanism responsible for lincomycin sorption by soil clay minerals. This was evidenced by pH-dependent sorption, and competition with inorganic cations for sorptive sites. As solution pH increased, lincomycin sorption decreased. The extent of reduction was consistent with the decrease in cationic lincomycin species in solution. The presence of Ca2+ in solution diminished lincomycin sorption. Clay interlayer hydration status strongly influenced lincomycin adsorption. Smectites with the charge deficit from isomorphic substitution in tetrahedral layers (i.e., saponite) manifest a less hydrated interlayer environment resulting in greater sorption than that by octahedrally substituted clays (i.e., montmorillonite). Strongly hydrated exchangeable cations resulted in a more hydrated clay interlayer environment reducing sorption in the order of Ca- < K- < Cs-smectite. X-ray diffraction revealed that lincomycin was intercalated in smectite clay interlayers. Sorption capacity was limited by clay surface area rather than by cation exchange capacity. Smectite interlayer hydration was shown to be a major, yet previously unrecognized, factor influencing the cation exchange process of lincomycin on aluminosilicate mineral surfaces.

Bioremediating Oil Spills in Nutrient Poor Ocean Waters Using Fertilized Clay Mineral Flakes: Some Experimental Constraints

PubMed Central

Warr, Laurence N.; Friese, André; Schwarz, Florian; Schauer, Frieder; Portier, Ralph J.; Basirico, Laura M.; Olson, Gregory M.

2013-01-01

Much oil spill research has focused on fertilizing hydrocarbon oxidising bacteria, but a primary limitation is the rapid dilution of additives in open waters. A new technique is presented for bioremediation by adding nutrient amendments to the oil spill using thin filmed minerals comprised largely of Fullers Earth clay. Together with adsorbed N and P fertilizers, filming additives, and organoclay, clay flakes can be engineered to float on seawater, attach to the oil, and slowly release contained nutrients. Our laboratory experiments of microbial activity on weathered source oil from the Deepwater Horizon spill in the Gulf of Mexico show fertilized clay treatment significantly enhanced bacterial respiration and consumption of alkanes compared to untreated oil-in-water conditions and reacted faster than straight fertilization. Whereas a major portion (up to 98%) of the alkane content was removed during the 1 month period of experimentation by fertilized clay flake interaction; the reduced concentration of polyaromatic hydrocarbons was not significantly different from the non-clay bearing samples. Such clay flake treatment could offer a way to more effectively apply the fertilizer to the spill in open nutrient poor waters and thus significantly reduce the extent and duration of marine oil spills, but this method is not expected to impact hydrocarbon toxicity. PMID:23864952

Bioremediating oil spills in nutrient poor ocean waters using fertilized clay mineral flakes: some experimental constraints.

PubMed

Warr, Laurence N; Friese, André; Schwarz, Florian; Schauer, Frieder; Portier, Ralph J; Basirico, Laura M; Olson, Gregory M

2013-01-01

Much oil spill research has focused on fertilizing hydrocarbon oxidising bacteria, but a primary limitation is the rapid dilution of additives in open waters. A new technique is presented for bioremediation by adding nutrient amendments to the oil spill using thin filmed minerals comprised largely of Fullers Earth clay. Together with adsorbed N and P fertilizers, filming additives, and organoclay, clay flakes can be engineered to float on seawater, attach to the oil, and slowly release contained nutrients. Our laboratory experiments of microbial activity on weathered source oil from the Deepwater Horizon spill in the Gulf of Mexico show fertilized clay treatment significantly enhanced bacterial respiration and consumption of alkanes compared to untreated oil-in-water conditions and reacted faster than straight fertilization. Whereas a major portion (up to 98%) of the alkane content was removed during the 1 month period of experimentation by fertilized clay flake interaction; the reduced concentration of polyaromatic hydrocarbons was not significantly different from the non-clay bearing samples. Such clay flake treatment could offer a way to more effectively apply the fertilizer to the spill in open nutrient poor waters and thus significantly reduce the extent and duration of marine oil spills, but this method is not expected to impact hydrocarbon toxicity.

TRACE ELEMENT DISTRIBUTION IN SEDIMENTS OF THE MID-ATLANTIC RIDGE.

DTIC Science & Technology

MARINE GEOLOGY, ATLANTIC OCEAN), (*OCEAN BOTTOM, MINERALS), SEDIMENTATION, IRON, COBALT, MANGANESE, STRONTIUM, CHLORITES, NEUTRON ACTIVATION, GEOCHEMISTRY, CALCITE , CARBONATES, X RAY DIFFRACTION, CLAY MINERALS, THESES

The role of reaction affinity and secondary minerals in regulating chemical weathering rates at the Santa Cruz Soil Chronosequence, California

USGS Publications Warehouse

Maher, K.; Steefel, Carl; White, A.F.; Stonestrom, David A.

2009-01-01

In order to explore the reasons for the apparent discrepancy between laboratory and field weathering rates and to determine the extent to which weathering rates are controlled by the approach to thermodynamic equilibrium, secondary mineral precipitation, and flow rates, a multicomponent reactive transport model (CrunchFlow) was used to interpret soil profile development and mineral precipitation and dissolution rates at the 226 ka Marine Terrace Chronosequence near Santa Cruz, CA. Aqueous compositions, fluid chemistry, transport, and mineral abundances are well characterized [White A. F., Schulz M. S., Vivit D. V., Blum A., Stonestrom D. A. and Anderson S. P. (2008) Chemical weathering of a Marine Terrace Chronosequence, Santa Cruz, California. I: interpreting the long-term controls on chemical weathering based on spatial and temporal element and mineral distributions. Geochim. Cosmochim. Acta 72 (1), 36-68] and were used to constrain the reaction rates for the weathering and precipitating minerals in the reactive transport modeling. When primary mineral weathering rates are calculated with either of two experimentally determined rate constants, the nonlinear, parallel rate law formulation of Hellmann and Tisserand [Hellmann R. and Tisserand D. (2006) Dissolution kinetics as a function of the Gibbs free energy of reaction: An experimental study based on albite feldspar. Geochim. Cosmochim. Acta 70 (2), 364-383] or the aluminum inhibition model proposed by Oelkers et al. [Oelkers E. H., Schott J. and Devidal J. L. (1994) The effect of aluminum, pH, and chemical affinity on the rates of aluminosilicate dissolution reactions. Geochim. Cosmochim. Acta 58 (9), 2011-2024], modeling results are consistent with field-scale observations when independently constrained clay precipitation rates are accounted for. Experimental and field rates, therefore, can be reconciled at the Santa Cruz site. Additionally, observed maximum clay abundances in the argillic horizons occur at the depth and time where the reaction fronts of the primary minerals overlap. The modeling indicates that the argillic horizon at Santa Cruz can be explained almost entirely by weathering of primary minerals and in situ clay precipitation accompanied by undersaturation of kaolinite at the top of the profile. The rate constant for kaolinite precipitation was also determined based on model simulations of mineral abundances and dissolved Al, SiO2(aq) and pH in pore waters. Changes in the rate of kaolinite precipitation or the flow rate do not affect the gradient of the primary mineral weathering profiles, but instead control the rate of propagation of the primary mineral weathering fronts and thus total mass removed from the weathering profile. Our analysis suggests that secondary clay precipitation is as important as aqueous transport in governing the amount of dissolution that occurs within a profile because clay minerals exert a strong control over the reaction affinity of the dissolving primary minerals. The modeling also indicates that the weathering advance rate and the total mass of mineral dissolved is controlled by the thermodynamic saturation of the primary dissolving phases plagioclase and K-feldspar, as is evident from the difference in propagation rates of the reaction fronts for the two minerals despite their very similar kinetic rate laws. ?? 2009 Elsevier Ltd.

Meso- and microscale structures related to post-magmatic deformation of the outer Izu-Bonin-Mariana fore arc system: preliminary results from IODP Expedition 352

NASA Astrophysics Data System (ADS)

Micheuz, P.; Kurz, W.; Ferre, E. C.

2015-12-01

IODP Expedition 352 aimed to drill through the entire volcanic sequence of the Bonin fore arc. Four sites were drilled, two on the outer fore arc and two on the upper trench slope. Analysis of structures within drill cores, combined with borehole and site survey seismic data, indicates that tectonic deformation in the outer Izu-Bonin-Mariana fore arc is mainly post-magmatic, associated with the development of syn-tectonic sedimentary basins. Within the magmatic basement, deformation was accommodated by shear along cataclastic fault zones, and the formation of tension fractures, hybrid (tension and shear) fractures, and shear fractures. Veins commonly form by mineral filling of tension or hybrid fractures and, generally, show no or limited observable macroscale displacement along the fracture plane. The vein filling generally consists of (Low Mg-) calcite and/or various types of zeolite as well as clay. Vein frequency varies with depth but does not seem to correlate with the proximity of faults. This may indicate that these veins are genetically related to hydrothermal activity taking place shortly after magma cooling. Host-rock fragments are commonly embedded within precipitated vein material pointing to a high fluid pressure. Vein thickness varies from < 1 mm up to 15 mm. The wider veins appear to have formed in incremental steps of extension. Calcite veins tend to be purely dilational at shallow depths, but gradually evolve towards oblique tensional veins at depth, as shown by the growth of stretched calcite and/or zeolites (idiomorphic and/or stretched) with respect to vein margins. With increasing depth, the calcite grains exhibit deformation microstructures more frequently than at shallower core intervals. These microstructures include thin twinning (type I twins), increasing in width with depth (type I and type II twins), curved twins, and subgrain boundaries indicative of incipient plastic deformation.

Hydrolysis of oligosaccharides over solid acid catalysts: a review.

PubMed

Vilcocq, Léa; Castilho, Paula C; Carvalheiro, Florbela; Duarte, Luís C

2014-04-01

Mild fractionation/pretreatment processes are becoming the most preferred choices for biomass processing within the biorefinery framework. To further explore their advantages, new developments are needed, especially to increase the extent of the hydrolysis of poly- and oligosaccharides. A possible way forward is the use of solid acid catalysts that may overcome many current drawbacks of other common methods. In this Review, the advantages and limitations of the use of heterogeneous catalysis for the main groups of solid acid catalysts (zeolites, resins, carbon materials, clays, silicas, and other oxides) and their relation to the hydrolysis of model soluble disaccharides and soluble poly- and oligosaccharides are presented and discussed. Special attention is given to the hydrolysis of hemicelluloses and hemicellulose-derived saccharides into monosaccharides, the impact on process performance of potential catalyst poisons originating from biomass and biomass hydrolysates (e.g., proteins, mineral ions, etc.). The data clearly point out the need for studying hemicelluloses in natura rather than in model compound solutions that do not retain the relevant factors influencing process performance. Furthermore, the desirable traits that solid acid catalysts must possess for the efficient hemicellulose hydrolysis are also presented and discussed with regard to the design of new catalysts. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The origin and emergence of life under impact bombardment

PubMed Central

Cockell, Charles S

2006-01-01

Craters formed by asteroids and comets offer a number of possibilities as sites for prebiotic chemistry, and they invite a literal application of Darwin's ‘warm little pond’. Some of these attributes, such as prolonged circulation of heated water, are found in deep-ocean hydrothermal vent systems, previously proposed as sites for prebiotic chemistry. However, impact craters host important characteristics in a single location, which include the formation of diverse metal sulphides, clays and zeolites as secondary hydrothermal minerals (which can act as templates or catalysts for prebiotic syntheses), fracturing of rock during impact (creating a large surface area for reactions), the delivery of iron in the case of the impact of iron-containing meteorites (which might itself act as a substrate for prebiotic reactions), diverse impact energies resulting in different rates of hydrothermal cooling and thus organic syntheses, and the indiscriminate nature of impacts into every available lithology—generating large numbers of ‘experiments’ in the origin of life. Following the evolution of life, craters provide cryptoendolithic and chasmoendolithic habitats, particularly in non-sedimentary lithologies, where limited pore space would otherwise restrict colonization. In impact melt sheets, shattered, mixed rocks ultimately provided diverse geochemical gradients, which in present-day craters support the growth of microbial communities. PMID:17008223

Formulation of stable Bacillus subtilis AH18 against temperature fluctuation with highly heat-resistant endospores and micropore inorganic carriers.

PubMed

Chung, Soohee; Lim, Hyung Mi; Kim, Sang-Dal

2007-08-01

To survive the commercial market and to achieve the desired effect of beneficial organisms, the strains in microbial products must be cost-effectively formulated to remain dormant and hence survive through high and low temperatures of the environment during transportation and storage. Dormancy and stability of Bacillus subtilis AH18 was achieved by producing endospores with enhanced heat resistance and using inorganic carriers. Heat stability assays, at 90 degrees C for 1 h, showed that spores produced under a sublethal temperature of 57 degrees C was 100 times more heat-resistant than the ones produced by food depletion at the growing temperature of 37 degrees C. When these highly heat-resistant endospores were formulated with inorganic carriers of natural and synthetic zeolite or kaolin clay minerals having substantial amount of micropores, the dormancy of the endospores was maintained for 6 months at 15-25 degrees C. Meanwhile, macroporous perlite carriers with average pore diameter larger than 3.7 microm stimulated the germination of the spores and rapid proliferation of the bacteria. These results indicated that a B. subtilis AH18 product that can remain dormant and survive through environmental temperature fluctuation can be formulated by producing heat-stressed endospores and incorporating inorganic carriers with micropores in the formulation step.

Direct evidence for organic carbon preservation as clay-organic nanocomposites in a Devonian black shale; from deposition to diagenesis

NASA Astrophysics Data System (ADS)

Kennedy, Martin John; Löhr, Stefan Carlos; Fraser, Samuel Alex; Baruch, Elizabeth Teresa

2014-02-01

The burial of marine sourced organic carbon (OC) in continental margin sediments is most commonly linked to oceanographic regulation of bottom-water oxygenation (anoxia) and/or biological productivity. Here we show an additional influence in the Devonian Woodford Shale, in which OC occurs as nanometer intercalations with specific phyllosilicate minerals (mixed-layer illite/smectite) that we term organo-mineral nanocomposites. High resolution transmission electron microscopic (HRTEM) images provide direct evidence of this nano-scale relationship. While discrete micron-scale organic particles, such as Tasmanites algal cysts, are present in some lamina, a strong relation between total organic carbon (TOC) and mineral surface area (MSA) over a range of 15% TOC indicate that the dominant association of organic carbon is with mineral surfaces and not as discrete pelagic grains, consistent with HRTEM images of nanocomposites. Where periods of oxygenation are indicated by bioturbation, this relationship is modified by a shift to lower OC loading on mineral surfaces and reduced MSA variability likely resulting from biological mixing and homogenization of the sediment, oxidative burn down of OC and/or stripping of OC from minerals in animal guts. The TOC-MSA relationship extends across a range of burial depths and thermal maturities into the oil window and persists through partial illitization. Where illitization occurs, the loss of mineral surface area associated with the collapse of smectite interlayer space results in a systematic increase in TOC:MSA and reorganization of organic carbon and clays into nano-scale aggregates. While the Woodford Shale is representative of black shale deposits commonly thought to record heightened marine productivity and/or anoxia, our results point to the importance of high surface area clay minerals for OC enrichment. Given that the vast majority of these clay minerals are formed in soils before being transported to continental margin settings, their mineralogy and attendant preservative potential is primarily a function of continental climate and provenance making these deposits a sensitive recorder of land as well as oceanographic change.

Geotechnical and mineralogical characteristics of marl deposits in Jordan

NASA Astrophysics Data System (ADS)

Shaqour, Fathi M.; Jarrar, Ghaleb; Hencher, Steve; Kuisi, Mostafa

2008-10-01

Marls and marly limestone deposits cover most of Northern Jordan, where Amman City and its suburbs are located. These deposits serve as foundations for most buildings and roads as well as fill material for structural back filling, especially road bases and sub-bases. The present study aims at investigating the geotechnical characteristics and mineral composition of the marl units of these deposits through field investigations and laboratory testing. Using X-ray diffraction technique along with chemical analysis, representative samples of marl horizons were tested for mineral composition, and for a set of index and geotechnical properties including: specific gravity, grain size, Atterberg limits, Proctor compaction and shear strength properties. The test results show a positive linear relationship as expected between the clay content and both liquid and plastic limits. The tests results also show an inverse linear relationship between the clay content and the maximum dry density in both standard and modified compaction. This is attributed to the adsorption of water by the clay minerals. The relationship is more prominent in the case of modified compaction test. The results also indicate a similar relationship for the angle of internal friction. No clear correlation between cohesion and clay content was apparent.

Biodegradation and adsorption of C1- and C2-phenanthrenes and C1- and C2-dibenzothiophenes in the presence of clay minerals: effect on forensic diagnostic ratios.

PubMed

Ugochukwu, Uzochukwu C; Head, Ian M; Manning, David A C

2014-07-01

The impact of modified montmorillonites on adsorption and biodegradation of crude oil C1-phenanthrenes, C1-dibenzothiophenes, C2-phenanthrenes and C2-dibenzothiophenes was investigated in aqueous clay/oil microcosm experiments with a hydrocarbon degrading microorganism community. Consequently, the effect on C1-dibenzothiophenes/C1-phenanthrenes, C2-dibenzothiophenes/C2-phenanthrenes, 2+3-methyldibenzothiophene/4-methyldibenzothiophene and 1-methyldibenzothiophene/4-methyldibenzothiophene ratios commonly used as diagnostic ratios for oil forensic studies was evaluated. The clay mineral samples were treated to produce acid activated montmorillonite, organomontmorillonite and homoionic montmorillonite which were used in this study. The different clay minerals (modified and unmodified) showed varied degrees of biodegradation and adsorption of the C1-phenanthrenes, C1-dibenzothiophenes, C2-phenanthrenes and C2-dibenzothiophenes. The study indicated that as opposed to biodegradation, adsorption has no effect on the diagnostic ratios. Among the diagnostic ratios reviewed, only C2-dibenzothiophenes/C2-phenanthrenes ratio was neither affected by adsorption nor biodegradation making this ratio very useful in forensic studies of oil spills and oil-oil correlation.

The acid-base titration of montmorillonite

NASA Astrophysics Data System (ADS)

Bourg, I. C.; Sposito, G.; Bourg, A. C.

2003-12-01

Proton binding to clay minerals plays an important role in the chemical reactivity of soils (e.g., acidification, retention of nutrients or pollutants). If should also affect the performance of clay barriers for waste disposal. The surface acidity of clay minerals is commonly modelled empirically by assuming generic amphoteric surface sites (>SOH) on a flat surface, with fitted site densities and acidity constant. Current advances in experimental methods (notably spectroscopy) are rapidly improving our understanding of the structure and reactivity of the surface of clay minerals (arrangement of the particles, nature of the reactive surface sites, adsorption mechanisms). These developments are motivated by the difficulty of modelling the surface chemistry of mineral surfaces at the macro-scale (e.g., adsorption or titration) without a detailed (molecular-scale) picture of the mechanisms, and should be progressively incorporated into surface complexation models. In this view, we have combined recent estimates of montmorillonite surface properties (surface site density and structure, edge surface area, surface electrostatic potential) with surface site acidities obtained from the titration of alpha-Al2O3 and SiO2, and a novel method of accounting for the unknown initial net proton surface charge of the solid. The model predictions were compared to experimental titrations of SWy-1 montmorillonite and purified MX-80 bentonite in 0.1-0.5 mol/L NaClO4 and 0.005-0.5 mol/L NaNO3 background electrolytes, respectively. Most of the experimental data were appropriately described by the model after we adjusted a single parameter (silanol sites on the surface of montmorillonite were made to be slightly more acidic than those of silica). At low ionic strength and acidic pH the model underestimated the buffering capacity of the montmorillonite, perhaps due to clay swelling or to the interlayer adsorption of dissolved aluminum. The agreement between our model and the experimental data illustrates the complementarity of molecular and macro-scale descriptions of the clay reactivity.

Raman spectroscopy, an innovative tool to explore the mineralogy and provenance of dust (1-5 µm): Dome B ice core, East Antarctica

NASA Astrophysics Data System (ADS)

Ileana Paleari, Chiara; Andò, Sergio; Delmonte, Barbara; Maggi, Valter; Garzanti, Eduardo

2017-04-01

The polar ice sheets are invaluable archives preserving information about past climate changes and atmosphere composition. Deep ice cores from Greenland and Antarctica provide records of several climate-dependent proxies allowing climate reconstructions at different time scales, among which greenhouse gases, atmospheric aerosol and aeolian dust. In this project, the mineralogy of dust preserved in the Dome B (77°05'S, 94°55'E, 3650 m a.s.l.) ice core was investigated using Raman spectroscopy. The thermal drilled ice core, made during the 1987-1988 Austral season by the 33rd Soviet Antarctic Expedition, covers the last 30 kyr. The record thus encompasses the last glacial period, the Last Glacial Maximum (LGM), the deglaciation and the beginning of the Holocene. Four Dome B ice core samples from the LGM were selected, and the mineralogical fingerprint of dust particles was investigated. Dust in central Antarctic ice cores is clay to finest silt, the volume-size distribution of particles showing modal values around 2-2.6 µm at the Dome B site. Detrital minerals of such a fine grain-size range are exceedingly difficult to determine one by one, a task that to the best of our knowledge has never been accomplished so far. In order to meet this challenge, we have developed a new protocol for the preparation and analysis of particles between 1 and 5 µm in diameter, in a clean room at the EuroCold Lab and at the Laboratory for Provenance Studies of Milano-Bicocca University. Three slides were prepared for each sample, and 962 particles were studied overall. In total, 41 different minerals were recognized, including species derived from granitoid, metamorphic or siliciclastic rocks (e.g., quartz, feldspars and phyllosilicates), from volcanic source rocks (e.g., sanidine, anorthite, pyroxenes, zeolites) associated with biogenic marine aragonite and iron oxides probably derived from erosion of soil profiles. Our observations indicate southern South America as the most likely dominant dust source for Dome B during the LGM. Abundant carbonates found in samples DB620 and DB631 highlights the role of the exposed Argentine continental shelf as a significant additional dust source during the sea-level low-stand period of Marine Isotopic Stage 2. This study demonstrates that dust minerals as small as 1-5 µm can be identified with single-grain method by Raman Spectroscopy, opening up a new frontier in provenance studies of silt-sized sediments down to the size limit of clay.

Study of gamma spectrometry laboratory measurement in various sediment and vulcanic rocks

NASA Astrophysics Data System (ADS)

Nurhandoko, Bagus Endar B.; Kurniadi, Rizal; Rizka Asmara Hadi, Muhammad; Rizal Komara, Insan

2017-01-01

Gamma-ray spectroscopy is the quantitative study of the energy spectra of gamma-ray sources. This method is powerful to characterize some minerals, especially to differentiate rocks which contains among Potassium, Uranium, dan Thorium. Rock contains radioactive material which produce gamma rays in various energies and intensities. When these emissions are detected and analyzed with a spectroscopy system, a gamma-ray energy spectrum can be used as indicator for mineral content of rock. Some sediment and vulcanic rock have been collected from East Java Basin. Samples are ranging from Andesite vulcanics, Tuff, Shale, various vulcanic clay and Alluvial clay. We present some unique characteristics of gamma spectrometry in various sedimentar and vulcanic rocks of East Java Basins. Details contents of gamma ray spectra give enrichments to characterize sample of sediment and vulcanic in East Java. Weathered vulcanic clay has lower counting rate of gamma ray than alluvial deltaic clay counting rate. Therefore, gamma spectrometrometry can be used as tool for characterizing the enviroment of clay whether vulcanic or alluvial-deltaic. This phenomena indicates that gamma ray spectrometry can be as tool for characterizing the clay whether it tends to Smectite or Illite

Diagenesis and clay mineral formation at Gale Crater, Mars

PubMed Central

Bridges, J C; Schwenzer, S P; Leveille, R; Westall, F; Wiens, R C; Mangold, N; Bristow, T; Edwards, P; Berger, G

2015-01-01

The Mars Science Laboratory rover Curiosity found host rocks of basaltic composition and alteration assemblages containing clay minerals at Yellowknife Bay, Gale Crater. On the basis of the observed host rock and alteration minerals, we present results of equilibrium thermochemical modeling of the Sheepbed mudstones of Yellowknife Bay in order to constrain the formation conditions of its secondary mineral assemblage. Building on conclusions from sedimentary observations by the Mars Science Laboratory team, we assume diagenetic, in situ alteration. The modeling shows that the mineral assemblage formed by the reaction of a CO2-poor and oxidizing, dilute aqueous solution (Gale Portage Water) in an open system with the Fe-rich basaltic-composition sedimentary rocks at 10–50°C and water/rock ratio (mass of rock reacted with the starting fluid) of 100–1000, pH of ∽7.5–12. Model alteration assemblages predominantly contain phyllosilicates (Fe-smectite, chlorite), the bulk composition of a mixture of which is close to that of saponite inferred from Chemistry and Mineralogy data and to that of saponite observed in the nakhlite Martian meteorites and terrestrial analogues. To match the observed clay mineral chemistry, inhomogeneous dissolution dominated by the amorphous phase and olivine is required. We therefore deduce a dissolving composition of approximately 70% amorphous material, with 20% olivine, and 10% whole rock component. PMID:26213668

Diagenesis and clay mineral formation at Gale Crater, Mars

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bridges, J. C.; Schwenzer, S. P.; Leveille, R.

The Mars Science Laboratory rover Curiosity found host rocks of basaltic composition and alteration assemblages containing clay minerals at Yellowknife Bay, Gale Crater. On the basis of the observed host rock and alteration minerals, we present results of equilibrium thermochemical modeling of the Sheepbed mudstones of Yellowknife Bay in order to constrain the formation conditions of its secondary mineral assemblage. Building on conclusions from sedimentary observations by the Mars Science Laboratory team, we assume diagenetic, in situ alteration. The modeling shows that the mineral assemblage formed by the reaction of a CO₂-poor and oxidizing, dilute aqueous solution (Gale Portage Water)more » in an open system with the Fe-rich basaltic-composition sedimentary rocks at 10–50°C and water/rock ratio (mass of rock reacted with the starting fluid) of 100–1000, pH of ~7.5–12. Model alteration assemblages predominantly contain phyllosilicates (Fe-smectite, chlorite), the bulk composition of a mixture of which is close to that of saponite inferred from Chemistry and Mineralogy data and to that of saponite observed in the nakhlite Martian meteorites and terrestrial analogues. To match the observed clay mineral chemistry, inhomogeneous dissolution dominated by the amorphous phase and olivine is required. We therefore deduce a dissolving composition of approximately 70% amorphous material, with 20% olivine, and 10% whole rock component.« less

Diagenesis and clay mineral formation at Gale Crater, Mars

DOE PAGES

Bridges, J. C.; Schwenzer, S. P.; Leveille, R.; ...

2015-01-18

The Mars Science Laboratory rover Curiosity found host rocks of basaltic composition and alteration assemblages containing clay minerals at Yellowknife Bay, Gale Crater. On the basis of the observed host rock and alteration minerals, we present results of equilibrium thermochemical modeling of the Sheepbed mudstones of Yellowknife Bay in order to constrain the formation conditions of its secondary mineral assemblage. Building on conclusions from sedimentary observations by the Mars Science Laboratory team, we assume diagenetic, in situ alteration. The modeling shows that the mineral assemblage formed by the reaction of a CO₂-poor and oxidizing, dilute aqueous solution (Gale Portage Water)more » in an open system with the Fe-rich basaltic-composition sedimentary rocks at 10–50°C and water/rock ratio (mass of rock reacted with the starting fluid) of 100–1000, pH of ~7.5–12. Model alteration assemblages predominantly contain phyllosilicates (Fe-smectite, chlorite), the bulk composition of a mixture of which is close to that of saponite inferred from Chemistry and Mineralogy data and to that of saponite observed in the nakhlite Martian meteorites and terrestrial analogues. To match the observed clay mineral chemistry, inhomogeneous dissolution dominated by the amorphous phase and olivine is required. We therefore deduce a dissolving composition of approximately 70% amorphous material, with 20% olivine, and 10% whole rock component.« less

Clay minerals behaviour in thin sandy clay-rich lacustrine turbidites (Lake Hazar, Turkey)

NASA Astrophysics Data System (ADS)

El Ouahabi, Meriam; Hubert-Ferrari, Aurelia; Lamair, Laura; Hage, Sophie

2017-04-01

Turbidites have been extensively studied in many different areas using cores or outcrop, which represent only an integrated snapshot of a dynamic evolving flow. Laboratory experiments provide the missing relationships between the flow characteristics and their deposits. In particular, flume experiments emphasize that the presence of clay plays a key role in turbidity current dynamics. Clay fraction, in small amount, provides cohesive strength to sediment mixtures and can damp turbulence. However, the degree of flocculation is dependent on factors such as the amount and size of clay particles, the surface of clay particles, chemistry and pH conditions in which the clay particles are dispersed. The present study focuses on thin clayey sand turbidites found in Lake Hazar (Turkey) occurring in stacked thin beds. Depositional processes and sources have been previously studied and three types were deciphered, including laminar flows dominated by cohesion, transitional, and turbulence flow regimes (Hage et al., in revision). For the purpose of determine the clay behavior in the three flow regimes, clay mineralogical, geochemical measurements on the cores allow characterising the turbidites. SEM observations provide further information regarding the morphology of clay minerals and other clasts. The study is particularly relevant given the highly alkaline and saline water of the Hazar Lake. Clay minerals in Hazar Lake sediments include kaolinite (1:1-type), illite and chlorite (2:1-type). Hazar lake water is alkaline having pH around 9.3, in such alkaline environment, a cation-exchange reaction takes place. Furthermore, in saline water (16‰), salts can act as a shield and decrease the repulsive forces between clay particle surfaces. So, pH and salt content jointly impact the behaviour of clays differently. Since the Al-faces of clay structures have a negative charge in basic solutions. At high pH, all kaolinite surfaces become negative-charged, and then kaolinite particles are dispersed, and the suspension is stabilized supported by our SEM observations. In alkaline water, kaolinite reveals a lower degree of consolidation. While, alkaline water has no measurable effect on illite and chlorite surface properties due to the absence of modifications in charge. Illite and chlorite form with other clasts clusters or aggregate structures in suspension when the particle interactions are dominated by attractive energies were formed. The aggregate structure plays a major part in the flow behavior of clay suspensions. Flocs will immobilize the suspending medium, and give rise to increasing viscosity and yield strength of the suspension. S. Hage, A. Hubert-Ferrari, L. Lamair, U. Avşar, M. El Ouahabi, M. Van Daele, F. Boulvain, M.A. Bahri, A. Seret, Al. Plenevaux. Flow dynamics at the origin of thin sandy clay-rich lacustrine turbidites: Examples from Lake Hazar, Turkey, submitted to Sedimentology, in revision.

Rock Physics and Petrographic Parameters Relationship Within Siliciclastic Rocks: Quartz Sandstone Outcrop Study Case

NASA Astrophysics Data System (ADS)

Syafriyono, S.; Caesario, D.; Swastika, A.; Adlan, Q.; Syafri, I.; Abdurrokhim, A.; Mardiana, U.; Mohamad, F.; Alfadli, M. K.; Sari, V. M.

2018-03-01

Rock physical parameters value (Vp and Vs) is one of fundamental aspects in reservoir characterization as a tool to detect rock heterogenity. Its response is depend on several reservoir conditions such as lithology, pressure and reservoir fluids. The value of Vp and Vs is controlled by grain contact and contact stiffness, a function of clay mineral content and porosity also affected by mineral composition. The study about Vp and Vs response within sandstone and its relationship with petrographic parameters has become important to define anisotrophy of reservoir characteristics distribution and could give a better understanding about local diagenesis that influence clastic reservoir properties. Petrographic analysis and Vp-Vs calculation was carried out to 12 core sample which is obtained by hand-drilling of the outcrop in Sukabumi area, West Java as a part of Bayah Formation. Data processing and interpretation of sedimentary vertical succession showing that this outcrop comprises of 3 major sandstone layers indicating fluvial depositional environment. As stated before, there are 4 petrographic parameters (sorting, roundness, clay mineral content, and grain contact) which are responsible to the differences of shear wave and compressional wave value in this outcrop. Lithology with poor-sorted and well- roundness has Vp value lower than well-sorted and poor-roundness (sub-angular) grain. For the sample with high clay content, Vp value is ranging from 1681 to 2000 m/s and could be getting high until 2190 to 2714 m/s in low clay content sample even though the presence of clay minerals cannot be defined neither as matrix nor cement. The whole sample have suture grain contact indicating telogenesis regime whereas facies has no relationship with Vp and Vs value because of the different type of facies show similar petrographic parameters after diagenesis.

Plant community change mediates the response of foliar δ(15)N to CO 2 enrichment in mesic grasslands.

PubMed

Polley, H Wayne; Derner, Justin D; Jackson, Robert B; Gill, Richard A; Procter, Andrew C; Fay, Philip A

2015-06-01

Rising atmospheric CO2 concentration may change the isotopic signature of plant N by altering plant and microbial processes involved in the N cycle. CO2 may increase leaf δ(15)N by increasing plant community productivity, C input to soil, and, ultimately, microbial mineralization of old, (15)N-enriched organic matter. We predicted that CO2 would increase aboveground productivity (ANPP; g biomass m(-2)) and foliar δ(15)N values of two grassland communities in Texas, USA: (1) a pasture dominated by a C4 exotic grass, and (2) assemblages of tallgrass prairie species, the latter grown on clay, sandy loam, and silty clay soils. Grasslands were exposed in separate experiments to a pre-industrial to elevated CO2 gradient for 4 years. CO2 stimulated ANPP of pasture and of prairie assemblages on each of the three soils, but increased leaf δ(15)N only for prairie plants on a silty clay. δ(15)N increased linearly as mineral-associated soil C declined on the silty clay. Mineral-associated C declined as ANPP increased. Structural equation modeling indicted that CO2 increased ANPP partly by favoring a tallgrass (Sorghastrum nutans) over a mid-grass species (Bouteloua curtipendula). CO2 may have increased foliar δ(15)N on the silty clay by reducing fractionation during N uptake and assimilation. However, we interpret the soil-specific, δ(15)N-CO2 response as resulting from increased ANPP that stimulated mineralization from recalcitrant organic matter. By contrast, CO2 favored a forb species (Solanum dimidiatum) with higher δ(15)N than the dominant grass (Bothriochloa ischaemum) in pasture. CO2 enrichment changed grassland δ(15)N by shifting species relative abundances.

Carbonation of Clay Minerals Exposed to scCO2/Water at 200 degrees and 250 degrees C

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sugama, T.; Ecker, L.; Gill, S.

2010-11-01

To clarify the mechanisms of carbonation of clay minerals, such as bentonite, kaolinite, and soft clay, we exposed them to supercritical carbon dioxide (scCO2)/water at temperatures of 200 and 250 C and pressures of 1500 and 2000 psi for 72- and 107-hours. Bentonite, comprising three crystalline phases, montmorillonite (MMT), anorthoclase-type albite, and quartz was susceptible to reactions with ionic carbonic acid yielded by the interactions between scCO2 and water, particularly MMT and anorthoclase-type albite phases. For MMT, the cation-exchangeable ions, such as Na+ and Ca2+, present in its basal interplanar space, were replaced by proton, H+, from ionic carbonic acid;more » thereafter, the cations leaching from MMT directly reacted with CO32- as a counter ion of H+ to form carbonate compounds. Such in-situ carbonation process in basal space caused the shrinkage and breakage of the spacing structure within MMT. In contrast, the wet carbonation of anorthoclase-type albite, categorized as rock minerals, entailed the formation of three amorphous by-products, such as carbonates, kaolinite-like compounds, and silicon dioxide. Together, these two different carbonations caused the disintegration and corruption of bentonite. Kaolinite clay containing the amorphous carbonates and silicon dioxide was inert to wet carbonation. We noted only a gain in weight due to its water uptake, suggesting that kaolinite-like by-products generated by the wet carbonation of rock minerals might remain unchanged even during extended exposure. Soft clay consisting of two crystalline phases, dolomite and silicon dioxide, also was unaltered by wet carbonation, despite the uptake of water.« less

Characterizing and Quantifying Emissions and Transport of Fugitive Dust Emissions Due to Department of Defense Activities

DTIC Science & Technology

2015-09-19

response to shear stress (τ, N m-2) induced by the PI-SWERL®, the viscosity of the fluid exerts a torque (N m-1) that eventually balances with τ. The...Engelbrecht et al. (2012) from CCSEM measurements, report that these silicate mineral particles are largely coated by a veneer of clay minerals and fine...content does not, by itself, contribute to the high emissions observed at YTC. The presence of high clay content can constrain the emissions by

Heavy Metal Soil Contamination at U.S. Army Installations: Proposed Research and Strategy for Technology Development

DTIC Science & Technology

1994-03-01

substrates that form the basis of the soil, such as carbonates, clay minerals, organic matter, iron and manganese oxides and hydroxides, sulfides, or...32 10 25 2.5 32 to 64 7 20 1.4 Total 100 200.7 interstitial water, clay minerals, sulfides, carbonates, organic matter, hydrous iron and manganese ...condensation reaction with OH- groups on the surface of (silicon, iron, manganese , and aluminum) com- pounds (Calmano and Forsmer 1983). Sorption-based

Evidence for ammonium-bearing minerals in Ceres

NASA Technical Reports Server (NTRS)

King, T. V. V.; Clark, R. N.; Calvin, W. M.; Sherman, D. M.; Swayze, G. A.; Brown, R. H.

1991-01-01

Evidence for ammonium-bearing minerals was found on the surface of the largest asteroid Ceres. The presence of ammonium-bearing clays suggests that Ceres has experienced a period of alteration by substantial amounts of an ammonium-bearing fluid. The presence of the ammonium-bearing clays does not preclude Ceres maintaining a volatile inventory in the core or in a volatile-rich zone at some distance below the surface. Telescopic observations of Ceres, using the 3.0 meter NASA Infrared telescope facility prompted this reevaluation of its surface mineralogy.

Implications of abundant hygroscopic minerals in the Martian regolith

NASA Technical Reports Server (NTRS)

Clark, B. C.

1978-01-01

Converging lines of evidence suggest that a significant portion of the Martian surface fines may consist of salts and smectite clays. Salts can form stoichiometric hydrates as well as eutectic solutions with depressed freezing points; clays contain bound water of constitution and adsorb significant quantities of water from the vapor phase. The formation of ice may be suppressed by these minerals in some regions on Mars, and their presence in abundance would imply important consequences for atmospheric and geologic processes and the prospects for exobiology.

Hydrothermal Synthesis of Analcime from Kutingkeng Formation Mudstone

NASA Astrophysics Data System (ADS)

Hsiao, Yin-Hsiu; Chen, Kuan-Ting; Ray, Dah-Tong

2015-04-01

In southwest of Taiwan, the foothill located in Tainan-Kaohsiung city is the exposed area of Pliocene strata to early Pleistocene strata. The strata are about a depth of five thousand, named as Kutigkeng Formation. The outcrop of Kutigkeng Formation is typical badlands, specifically called 'Moon World.' It is commonly known as no important economic applications of agricultural land. The mineral compositions of Kutingkeng Formation are quartz, clay minerals and feldspar. The clay minerals consist of illite, clinochlore and swelling clays. To study how the phase and morphology of analcime formed by hydrothermal synthesis were affected, analcime was synthesized from the mudstone of Kutinkeng Formation with microwave hydrothermal reaction was investigated. The parameters of the experiment were the reaction temperature, the concentration of mineralizer, solids/liquid ratio and time. The sodium silicate (Na2SiO3) were used as mineralizer. The results showed that the analcime could be synthesized by hydrothermal reaction above 180° from Kutinkeng Formation mudstone samples. At the highest temperature (240°) of this study, the high purity analcime could be produced. When the concentration of Na2SiO3=3~6M, analcime could be synthesized at 240°. The best solids/liquid ratio was approximate 1 to 5. The hydrothermal reaction almost was completed after 4 hours.

Mineral resource potential map of the Savannah Roadless Area, Liberty County, Florida

USGS Publications Warehouse

Patterson, Sam H.; Schmidt, Walter; Crandall, Thomas M.

1982-01-01

The Savannah Roadless Area is underlain by sedimentary rocks having low potential for oil and gas and minerals. The low potential for oil or gas notwithstanding, the possibilities for discovery cannot be ruled out because the area and nearby lands have not been thoroughly explored. No minerals have been mined within the Savannah Roadless Area, and the only production nearby has been the digging of clayey sand used in stabilizing U.S. Forest Service roads. Fuller's earth, quartz sand and gravel, clayey sand, and common clay presently are produced elsewhere in the region, and limestone and peat have been produced in the past. No clay suitable for structural clay products or fuller's earth is present in the roadless area; however, a bed of quartz sand and gravel of excellent quality was penetrated at a depth interval of 37-50 ft by one drill hole. Although this bed is coarser grained-and therefore is more suitable for many uses-than the sand deposits worked elsewhere in the Big Bend region, its mineral resource potential is reduced by the thickness of overburden above it and by its distance from markets in population centers. The Apalachicola National Forest has been explored for phosphate and reconnoitered for heavy minerals, but no valuable deposits of either have been found.

Interaction of ordinary Portland cement and Opalinus Clay: Dual porosity modelling compared to experimental data

NASA Astrophysics Data System (ADS)

Jenni, A.; Gimmi, T.; Alt-Epping, P.; Mäder, U.; Cloet, V.

2017-06-01

Interactions between concrete and clays are driven by the strong chemical gradients in pore water and involve mineral reactions in both materials. In the context of a radioactive waste repository, these reactions may influence safety-relevant clay properties such as swelling pressure, permeability or radionuclide retention. Interfaces between ordinary Portland cement and Opalinus Clay show weaker, but more extensive chemical disturbance compared to a contact between low-pH cement and Opalinus Clay. As a consequence of chemical reactions porosity changes occur at cement-clay interfaces. These changes are stronger and may lead to complete pore clogging in the case of low-pH cements. The prediction of pore clogging by reactive transport simulations is very sensitive to the magnitude of diffusive solute fluxes, cement clinker chemistry, and phase reaction kinetics. For instance, the consideration of anion-depleted porosity in clays substantially influences overall diffusion and pore clogging at interfaces. A new concept of dual porosity modelling approximating Donnan equilibrium is developed and applied to an ordinary Portland cement - Opalinus Clay interface. The model predictions are compared with data from the cement-clay interaction (CI) field experiment in the Mt Terri underground rock laboratory (Switzerland), which represent 5 y of interaction. The main observations such as the decalcification of the cement at the interface, the Mg enrichment in the clay detached from the interface, and the S enrichment in the cement detached from the interface, are qualitatively predicted by the new model approach. The model results reveal multiple coupled processes that create the observed features. The quantitative agreement of modelled and measured data can be improved if uncertainties of key input parameters (tortuosities, reaction kinetics, especially of clay minerals) can be reduced.

Inter-layered clay stacks in Jurassic shales

NASA Technical Reports Server (NTRS)

Pye, K.; Krinsley, D. H.

1983-01-01

Scanning electron microscopy in the backscattered electron mode is used together with energy-dispersive X-ray microanalysis to show that Lower Jurassic shales from the North Sea Basin contain large numbers of clay mineral stacks up to 150 microns in size. Polished shale sections are examined to determine the size, shape orientation, textural relationships, and internal compositional variations of the clays. Preliminary evidence that the clay stacks are authigenic, and may have formed at shallow burial depths during early diagenesis, is presented.