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Sample records for hydrous oxide inorganic

  1. New inorganic (an)ion exchangers based on Mg-Al hydrous oxides: (alkoxide-free) sol-gel synthesis and characterisation.

    PubMed

    Chubar, Natalia

    2011-05-01

    New inorganic ion exchangers based on double Mg-Al hydrous oxides were generated via the new non-traditional sol-gel synthesis method which avoids using metal alkoxides as raw materials. Surface chemical and adsorptive properties of the final products were controlled by several ways of hydrogels and xerogels treatments which produced the materials of the layered structure, mixed hydrous oxides or amorphous adsorbents. The final adsorptive materials obtained via thermal treatment of xerogels were the layered mesoporous materials with carbonate in the interlayer space, surface abundance with hydroxylic groups and maximum adsorptive capacity to arsenate. Higher affinity of Mg-Al hydrous oxides towards H(2)AsO(4)(-) is confirmed by steep adsorption isotherms having plateau (removal capacity) at 220 mg[As]g(dw)(-1) for the best sample at pH=7, fast adsorption kinetics and little pH effect. Adsorption of arsenite, fluoride, bromate, bromide, selenate, borate by Mg-Al hydrous oxides was few times high either competitive (depending on the anion) as compare with the conventional inorganic ion exchange adsorbents. PMID:21345442

  2. Method for preparing hydrous zirconium oxide gels and spherules

    DOEpatents

    Collins, Jack L.

    2003-08-05

    Methods for preparing hydrous zirconium oxide spherules, hydrous zirconium oxide gels such as gel slabs, films, capillary and electrophoresis gels, zirconium monohydrogen phosphate spherules, hydrous zirconium oxide spherules having suspendable particles homogeneously embedded within to form a composite sorbent, zirconium monohydrogen phosphate spherules having suspendable particles of at least one different sorbent homogeneously embedded within to form a composite sorbent having a desired crystallinity, zirconium oxide spherules having suspendable particles homogeneously embedded within to form a composite, hydrous zirconium oxide fiber materials, zirconium oxide fiber materials, hydrous zirconium oxide fiber materials having suspendable particles homogeneously embedded within to form a composite, zirconium oxide fiber materials having suspendable particles homogeneously embedded within to form a composite and spherules of barium zirconate. The hydrous zirconium oxide spherules and gel forms prepared by the gel-sphere, internal gelation process are useful as inorganic ion exchangers, catalysts, getters and ceramics.

  3. Thin film hydrous metal oxide catalysts

    DOEpatents

    Dosch, Robert G.; Stephens, Howard P.

    1995-01-01

    Thin film (<100 nm) hydrous metal oxide catalysts are prepared by 1) synthesis of a hydrous metal oxide, 2) deposition of the hydrous metal oxide upon an inert support surface, 3) ion exchange with catalytically active metals, and 4) activating the hydrous metal oxide catalysts.

  4. Improved diffusive gradients in thin films (DGT) measurement of total dissolved inorganic arsenic in waters and soils using a hydrous zirconium oxide binding layer.

    PubMed

    Sun, Qin; Chen, Jing; Zhang, Hao; Ding, Shiming; Li, Zhu; Williams, Paul N; Cheng, Hao; Han, Chao; Wu, Longhua; Zhang, Chaosheng

    2014-03-18

    A high-capacity diffusive gradients in thin films (DGT) technique has been developed for measurement of total dissolved inorganic arsenic (As) using a long shelf life binding gel layer containing hydrous zirconium oxide (Zr-oxide). Both As(III) and As(V) were rapidly accumulated in the Zr-oxide gel and could be quantitatively recovered by elution using 1.0 M NaOH for freshwater or a mixture of 1.0 M NaOH and 1.0 M H2O2 for seawater. DGT uptake of As(III) and As(V) increased linearly with deployment time and was independent of pH (2.0-9.1), ionic strength (0.01-750 mM), the coexistence of phosphate (0.25-10 mg P L(-1)), and the aging of the Zr-oxide gel up to 24 months after production. The capacities of the Zr-oxide DGT were 159 μg As(III) and 434 μg As(V) per device for freshwater and 94 μg As(III) and 152 μg As(V) per device for seawater. These values were 5-29 times and 3-19 times more than those reported for the commonly used ferrihydrite and Metsorb DGTs, respectively. Deployments of the Zr-oxide DGT in As-spiked synthetic seawater provided accurate measurements of total dissolved inorganic As over the 96 h deployment, whereas ferrihydrite and Metsorb DGTs only measured the concentrations accurately up to 24 and 48 h, respectively. Deployments in soils showed that the Zr-oxide DGT was a reliable and robust tool, even for soil samples heavily polluted with As. In contrast, As in these soils was underestimated by ferrihydrite and Metsorb DGTs due to insufficient effective capacities, which were likely suppressed by the competing effects of phosphate.

  5. Method for preparing hydrous iron oxide gels and spherules

    DOEpatents

    Collins, Jack L.; Lauf, Robert J.; Anderson, Kimberly K.

    2003-07-29

    The present invention is directed to methods for preparing hydrous iron oxide spherules, hydrous iron oxide gels such as gel slabs, films, capillary and electrophoresis gels, iron monohydrogen phosphate spherules, hydrous iron oxide spherules having suspendable particles homogeneously embedded within to form composite sorbents and catalysts, iron monohydrogen phosphate spherules having suspendable particles of at least one different sorbent homogeneously embedded within to form a composite sorbent, iron oxide spherules having suspendable particles homogeneously embedded within to form a composite of hydrous iron oxide fiber materials, iron oxide fiber materials, hydrous iron oxide fiber materials having suspendable particles homogeneously embedded within to form a composite, iron oxide fiber materials having suspendable particles homogeneously embedded within to form a composite, dielectric spherules of barium, strontium, and lead ferrites and mixtures thereof, and composite catalytic spherules of barium or strontium ferrite embedded with oxides of Mg, Zn, Pb, Ce and mixtures thereof. These variations of hydrous iron oxide spherules and gel forms prepared by the gel-sphere, internal gelation process offer more useful forms of inorganic ion exchangers, catalysts, getters, dielectrics, and ceramics.

  6. Semivolatile organic (GC-MS) and inorganic analyses of groundwater samples during the hydrous pyrolysis/oxidation (HPO) field test in Visalia, CA, 1997

    SciTech Connect

    Chiarappa, M; Knauss, K G; Kumamoto, G; Leif, R N; Newmark, R L

    1998-02-05

    Hydrous pyrolysis/oxidation (HPO) is a novel, in situ, thermal-remediation technology that uses hot, oxygenated groundwater to completely oxidize a wide range of organic pollutants. A field demonstration of HPO was performed during the summer of 1997 at the Southern California Edison Pole Yard in Visalia, California, a site contaminated with creosote. The goal of the field experiment was to confirm the success of HPO under field remediation conditions. The groundwater was heated by steam injections, and oxygen was added by co-injection of compressed air. The progress of the HPO remediation process was evaluated by monitoring groundwater from multiple wells for dissolved oxygen, dissolved inorganic carbon, and dissolved organic contaminant levels. Analyses of groundwater chemistry allowed us to measure the concentrations of creosote components and to identify oxygenated intermediates produced by the HPO treatment. Dissolved organic carbon levels increased in response to steam injections because of the enhanced dissolution and mobilization of the creosote into the heated groundwater. Elevated concentrations of phenols and benzoic acid were measured in wells affected by the steam injections. Concentrations of other oxygenated compounds (i.e., fluorenone, anthrone, and 9,10-anthracenedione) increased in response to the steam injections. The production of these partially oxidized compounds is consistent with the aqueous-phase HPO reactions of creosote. Additional changes in the groundwater in response to steam injection were also consistent with the groundwater HPO chemistry. A drop in dissolved oxygen was observed in the aquifer targeted for the steam injections, and isotope shifts in the dissolved inorganic pool reflected the input of oxidized carbon derived from the creosote carbon.

  7. Adsorption of inorganic and organic ligands onto hydrous aluminum oxide: evaluation of surface charge and the impacts on particle and NOM removal during water treatment.

    PubMed

    Pommerenk, Peter; Schafran, Gary C

    2005-09-01

    The variable removal from solution of sulfate, orthophosphate, fluoride, five simple organic acids, and natural organic matterfromtwo sources by adsorption on aluminum hydroxide was examined to assess their potential influence on coagulation during drinking water treatment. Measurements of electrophoretic mobility were conducted with adsorption studies to provide means of evaluating the impact of the adsorption of these anions on the removal of particulate material during coagulation at water treatment facilities. The three inorganic ions exhibited widely different trends in terms of removal from solution and effect on the surface charge of the aluminum hydroxide. Phosphate was nearly completely removed from solution across a wide pH range and was observed to lower surface charge and shift the isoelectric point. Sulfate was removed to a lesser extent than phosphate, lowered the surface charge on the precipitate, but did not shiftthe isoelectric point. Fluoride was well-removed through adsorption but exhibited no influence on the charge of the hydrous aluminum oxide. The organic acids similarly displayed varying abilities to be removed through adsorption and different influences on surface charge. The results indicate the importance of the number and location of functional groups and their acid/ base properties. The ability to strongly influence surface charge illustrates the impact that adsorption of these anions can have on particle stability.

  8. Ion exchange properties of novel hydrous metal oxide materials

    SciTech Connect

    Gardner, T.J.; McLaughlin, L.I.

    1996-12-31

    Hydrous metal oxide (HMO) materials are inorganic ion exchangers which have many desirable characteristics for catalyst support applications, including high cation exchange capacity, anion exchange capability, high surface area, ease of adjustment of acidity and basicity, bulk or thin film preparation, and similar chemistry for preparation of various transition metal oxides. Cation exchange capacity is engineered into these materials through the uniform incorporation of alkali cations via manipulation of alkoxide chemistry. Specific examples of the effects of Na stoichiometry and the addition of SiO{sub 2} to hydrous titanium oxide (HTO) on ion exchange behavior will be given. Acid titration and cationic metal precursor complex exchange will be used to characterize the ion exchange behavior of these novel materials.

  9. Method for preparing hydrous titanium oxide spherules and other gel forms thereof

    DOEpatents

    Collins, J.L.

    1998-10-13

    The present invention are methods for preparing hydrous titanium oxide spherules, hydrous titanium oxide gels such as gel slabs, films, capillary and electrophoresis gels, titanium monohydrogen phosphate spherules, hydrous titanium oxide spherules having suspendible particles homogeneously embedded within to form a composite sorbent, titanium monohydrogen phosphate spherules having suspendible particles of at least one different sorbent homogeneously embedded within to form a composite sorbent having a desired crystallinity, titanium oxide spherules in the form of anatase, brookite or rutile, titanium oxide spherules having suspendible particles homogeneously embedded within to form a composite, hydrous titanium oxide fiber materials, titanium oxide fiber materials, hydrous titanium oxide fiber materials having suspendible particles homogeneously embedded within to form a composite, titanium oxide fiber materials having suspendible particles homogeneously embedded within to form a composite and spherules of barium titanate. These variations of hydrous titanium oxide spherules and gel forms prepared by the gel-sphere, internal gelation process offer more useful forms of inorganic ion exchangers, catalysts, getters and ceramics. 6 figs.

  10. Method for preparing hydrous titanium oxide spherules and other gel forms thereof

    DOEpatents

    Collins, Jack L.

    1998-01-01

    The present invention are methods for preparing hydrous titanium oxide spherules, hydrous titanium oxide gels such as gel slabs, films, capillary and electrophoresis gels, titanium monohydrogen phosphate spherules, hydrous titanium oxide spherules having suspendible particles homogeneously embedded within to form a composite sorbent, titanium monohydrogen phosphate spherules having suspendible particles of at least one different sorbent homogeneously embedded within to form a composite sorbent having a desired crystallinity, titanium oxide spherules in the form of anatase, brookite or rutile, titanium oxide spherules having suspendible particles homogeneously embedded within to form a composite, hydrous titanium oxide fiber materials, titanium oxide fiber materials, hydrous titanium oxide fiber materials having suspendible particles homogeneously embedded within to form a composite, titanium oxide fiber materials having suspendible particles homogeneously embedded within to form a composite and spherules of barium titanate. These variations of hydrous titanium oxide spherules and gel forms prepared by the gel-sphere, internal gelation process offer more useful forms of inorganic ion exchangers, catalysts, getters and ceramics.

  11. Iron oxidation state in hydrous rhyolites

    NASA Astrophysics Data System (ADS)

    Humphreys, M.; Brooker, R.; Fraser, D.; Smith, V. C.

    2012-12-01

    Recent studies have suggested that the Earth's mantle at subduction zones is oxidized relative to that at mid-ocean ridges. One possible origin of the oxidation is thought to be hydrous fluids, which are released into the mantle from the down-going slab during subduction. However, this is controversial; other studies have concluded that there is no intrinsic difference in oxidation state. One potential problem in determining primary oxidation states is that magmas produced by partial melting of the sub-arc mantle undergo significant degassing and crystallisation near the earth's surface, which may overprint the oxidation state of the primary melt. H2O contents of melt inclusions may be affected by partial re-equilibration. The effect of H2O on Fe oxidation state is unclear, although theoretical arguments typically predict increasing Fe3+/ΣFe during shallow degassing as a result of preferential diffusion of H2 out of the melt: FeO (m) + H2O (m) = Fe2O3 (m) + H2 (g) [1] We used XANES to measure Fe3+/Fe2+ in cylinders of rhyolitic obsidian that had been hydrated in gold capsules in cold-seal apparatus. Runs were performed at 850-900 °C under H2O-saturated conditions for short run times (20-80 minutes). Surprisingly, we find a positive correlation between Fe3+/ΣFe and H2O content of the glass. This is inconsistent with the effects of reaction [1], but can be explained by considering the acid-base properties of the hydrous melt. In particular, basic behaviour of FeO but amphoteric behaviour of Fe2O3, and changes in melt basicity relating to dissolution of H2O, can explain increasing Fe3+/Fe2+ with increasing H2O. We discuss the implications of these results for using melt compositions to infer the oxidation state of the earth's mantle.

  12. Formulation and method for preparing gels comprising hydrous aluminum oxide

    SciTech Connect

    Collins, Jack L.

    2014-06-17

    Formulations useful for preparing hydrous aluminum oxide gels contain a metal salt including aluminum, an organic base, and a complexing agent. Methods for preparing gels containing hydrous aluminum oxide include heating a formulation to a temperature sufficient to induce gel formation, where the formulation contains a metal salt including aluminum, an organic base, and a complexing agent.

  13. Formulation and method for preparing gels comprising hydrous hafnium oxide

    SciTech Connect

    Collins, Jack L; Hunt, Rodney D; Montgomery, Frederick C

    2013-08-06

    Formulations useful for preparing hydrous hafnium oxide gels contain a metal salt including hafnium, an acid, an organic base, and a complexing agent. Methods for preparing gels containing hydrous hafnium oxide include heating a formulation to a temperature sufficient to induce gel formation, where the formulation contains a metal salt including hafnium, an acid, an organic base, and a complexing agent.

  14. Formulation and method for preparing gels comprising hydrous cerium oxide

    DOEpatents

    Collins, Jack L; Chi, Anthony

    2013-05-07

    Formulations useful for preparing hydrous cerium oxide gels contain a metal salt including cerium, an organic base, and a complexing agent. Methods for preparing gels containing hydrous cerium oxide include heating a formulation to a temperature sufficient to induce gel formation, where the formulation contains a metal salt including cerium, an organic base, and a complexing agent.

  15. Hydrous oxide ion-exchange compound catalysts

    DOEpatents

    Dosch, Robert G.; Stephens, Howard P.

    1990-01-01

    A catalytic material of improved activity which comprises a hydrous, alkali metal or alkaline earth metal or quaternary ammonium titanate, zirconate, niobate, or tantalate, in which the metal or ammonium cations have been exchange with a catalytically effective quantity of a catalyst metal, and which has been subsequently treated with a solution of a Bronsted acid.

  16. Catalysis using hydrous metal oxide ion exchanges

    DOEpatents

    Dosch, Robert G.; Stephens, Howard P.; Stohl, Frances V.

    1985-01-01

    In a process which is catalyzed by a catalyst comprising an active metal on a carrier, said metal being active as a catalyst for the process, an improvement is provided wherein the catalyst is a hydrous, alkali metal or alkaline earth metal titanate, zirconate, niobate or tantalate wherein alkali or alkaline earth metal cations have been exchanged with a catalytically effective amount of cations of said metal.

  17. Catalysis using hydrous metal oxide ion exchangers

    DOEpatents

    Dosch, R.G.; Stephens, H.P.; Stohl, F.V.

    1983-07-21

    In a process which is catalyzed by a catalyst comprising an active metal on a carrier, said metal being active as a catalyst for the process, an improvement is provided wherein the catalyst is a hydrous, alkali metal or alkaline earth metal titanate, zirconate, niobate or tantalate wherein alkali or alkaline earth metal cations have been exchanged with a catalytically effective amount of cations of said metal.

  18. Hafnium Germanate from a Hydrous Hafnium Germanium Oxide Gel.

    PubMed

    Lambert, P. M.

    1998-03-23

    The gel chemistry of germanium is explored through the formation and composition of a hydrous metal oxide precursor gel used in the preparation of the HfGeO(4) and HfGeO(4):Ti X-ray phosphors. The enhanced solubility of hexagonal GeO(2) in dilute ammoniacal solutions is exploited to give a convenient and high-yield precipitation. The precursor gel is shown by FT-IR to be a diphasic mixture of hydrous hafnia and an ammonium germanate gel. Thermal treatment drives the crystallization of a hafnium-rich, simple tetragonal Hf(1)(-)(x)()Ge(x)()O(2) structure at 893 degrees C, that upon further heating to 1200 degrees C yields scheelite HfGeO(4).

  19. Adsorption of phosphate from aqueous solution by hydrous zirconium oxide.

    PubMed

    Rodrigues, Liana Alvares; Maschio, Leandro José; Coppio, Luciana de Simone Cividanes; Thim, Gilmar Patrocínio; da Silva, Maria Lúcia Caetano Pinto

    2012-06-01

    Synthetic ZrO2 x nH2O was used for phosphate removal from aqueous solution. The optimum adsorbent dose obtained for phosphate adsorption on to hydrous zirconium oxide was 0.1 g. The kinetic process was described very well by a pseudo-second-order rate model. The phosphate adsorption tended to increase with the decrease in pH. The adsorption capacity increased from 61 to 66 mg g(-1) when the temperature was increased from 298 to 338 K. A phosphate desorption of approximately 74% was obtained using water at pH 12.

  20. Thermal cleanups using dynamic underground stripping and hydrous pyrolysis oxidation

    SciTech Connect

    Aines, R D; Knauss, K; Leif, R; Newmark, R L

    1999-05-01

    In the early 1990s, in collaboration with the School of Engineering at the University of California, Berkeley, Lawrence Livermore National Laboratory developed dynamic underground stripping (DUS), a method for treating subsurface contaminants with heat that is much faster and more effective than traditional treatment methods. more recently, Livermore scientists developed hydrous pyrolysis/oxidation (HPO), which introduces both heat and oxygen to the subsurface to convert contaminants in the ground to such benign products as carbon dioxide, chloride ion, and water. This process has effectively destroyed all contaminants it encountered in laboratory tests. With dynamic underground stripping, the contaminants are vaporized and vacuumed out of the ground, leaving them still to be destroyed elsewhere. Hydrous pyrolysis/oxidation technology takes the cleanup process one step further by eliminating the treatment, handling, and disposal requirements and destroying the contamination in the ground. When used in combination, HPO is especially useful in the final polishing of a site containing significant free-product contaminant, once the majority of the contaminant has been removed.

  1. Synthesis and characterization of a mesoporous hydrous zirconium oxide used for arsenic removal from drinking water

    SciTech Connect

    Bortun, Anatoly; Bortun, Mila; Pardini, James; Khainakov, Sergei A.; Garcia, Jose R.

    2010-02-15

    Powder (20-50 {mu}m) mesoporous hydrous zirconium oxide was prepared from a zirconium salt granular precursor. The effect of some process parameters on product morphology, porous structure and adsorption performance has been studied. The use of hydrous zirconium oxide for selective arsenic removal from drinking water is discussed.

  2. Anodic deposition of hydrous ruthenium oxide for supercapacitors

    NASA Astrophysics Data System (ADS)

    Hu, Chi-Chang; Liu, Ming-Jue; Chang, Kuo-Hsin

    This communication demonstrates the success in the anodic deposition of hydrous ruthenium oxide (denoted as RuO 2· xH 2O) from RuCl 3· xH 2O in aqueous media with/without adding acetate ions (CH 3COO -, AcO -) as the complex agent. The benefits of as-deposited RuO 2· xH 2O include the low electron-hopping resistance and the low contact resistance at the Ti-RuO 2· xH 2O interface which are clarified in electrochemical impedance spectroscopic (EIS) studies. The cycling stability, specific capacitance, and power performance of as-deposited RuO 2· xH 2O are further improved by annealing in air at 150 °C for 2 h. The morphologies of as-deposited and annealed RuO 2· xH 2O films, examined by scanning electron microscopy (SEM), are very similar to that of thermally decomposed RuO 2. The high onset frequencies of 660 and 1650 Hz obtained from EIS spectra for the as-deposited and annealed RuO 2· xH 2O films, respectively, definitely illustrate the high-power merits of both oxide films prepared by means of the anodic deposition without considering the advantages of its simplicity, one-step, reliability, low cost, and versatility for electrode preparation.

  3. Dietary bioavailability of Cu adsorbed to colloidal hydrous ferric oxide

    USGS Publications Warehouse

    Cain, Daniel J.; Croteau, Marie-Noële; Fuller, Christopher C.

    2013-01-01

    The dietary bioavailability of copper (Cu) adsorbed to synthetic colloidal hydrous ferric oxide (HFO) was evaluated from the assimilation of 65Cu by two benthic grazers, a gastropod and a larval mayfly. HFO was synthesized, labeled with 65Cu to achieve a Cu/Fe ratio comparable to that determined in naturally formed HFO, and then aged. The labeled colloids were mixed with a food source (the diatom Nitzschia palea) to yield dietary 65Cu concentrations ranging from 211 to 2204 nmol/g (dry weight). Animals were pulse fed the contaminated diet and assimilation of 65Cu from HFO was determined following 1–3 days of depuration. Mass transfer of 65Cu from HFO to the diatom was less than 1%, indicating that HFO was the source of 65Cu to the grazers. Estimates of assimilation efficiency indicated that the majority of Cu ingested as HFO was assimilated (values >70%), implying that colloidal HFO potentially represents a source of dietary Cu to benthic grazers, especially where there is active formation and infiltration of these particles into benthic substrates.

  4. Preparation and evaluation of novel hydrous metal oxide (HMO)-supported noble metal catalysts

    SciTech Connect

    Gardner, T.J.; McLaughlin, L.I.; Evans, L.R.; Datye, A.K.

    1998-04-01

    Hydrous Metal Oxides (HMOs) are chemically synthesized materials that, because of their high cation exchange capacity, possess a unique ability to allow the preparation of highly dispersed supported-metal catalyst precursors with high metal loadings. This study evaluates high weight loading Rh/HMO catalysts with a wide range of HMO support compositions, including hydrous titanium oxide (HTO), silica-doped hydrous titanium oxide (HTO:Si), hydrous zirconium oxide (HZO), and silica-doped hydrous zirconium oxide (HZO:Si), against conventional oxide-supported Rh catalysts with similar weight loadings and support chemistries. Catalyst activity measurements for a structure-sensitive model reaction (n-butane hydrogenolysis) as a function of catalyst activation conditions show superior activity and stability for the ZrO{sub 2}, HZO, and HZO:Si supports, although all of the Rh/HMO catalysts have high ethane selectivity indicative of high Rh dispersion. For the TiO{sub 2}-, HTO-, and HTO:Si supported Rh catalysts, a significant loss of both catalyst activity and Rh dispersion is observed at more aggressive activation conditions, consistent with TiO{sub x} migration associated with SMSI phenomena. Of all the Rh/HMO catalysts, the Rh/HZO:Si catalysts appear to offer the best tradeoff in terms of high Rh dispersion, high activity, and high selectivity.

  5. Improved hydrous oxide ion-exchange compound catalysts

    DOEpatents

    Dosch, R.G.; Stephens, H.P.

    1986-04-09

    Disclosed is a catalytic material of improved activity which comprises a hydrous, alkali metal or alkaline earth metal or quaternary ammonium titanate, zirconate, niobate, or tantalate, in which the metal or ammonium cations have been exchanged with a catalytically effective quantity of a catalyst metal, and which has been subsequently treated with a solution of a Bronsted acid.

  6. Preparation and characterization of cellulose/hydrous niobium oxide hybrid.

    PubMed

    Maschio, Leandro José; Pereira, Paulo Henrique Fernandes; Da Silva, Maria Lucia Caetano Pinto

    2012-07-01

    A composite of cellulose extracted from bagasse with Nb2O5·nH2O in three different proportions (16.67, 37.5 and 50.0 wt%) was prepared using the co-precipitation method. The materials were characterized by X-ray diffractometry (XRD), Fourier transform infra-red spectroscopy (FTIR), thermogravimetric analysis (TG/DTG), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). TG data obtained show that the presence of inorganic material influenced slightly the stability of the hybrid material. The precipitation of 16.67 wt.% of oxide was sufficient to inhibit the combustion peaks present in the DSC curve of cellulose. This work will help find new applications for these materials.

  7. RATES OF HYDROUS FERRIC OXIDE CRYSTALLIZATION AND THE INFLUENCE ON COPRECIPITATED ARSENATE

    EPA Science Inventory

    Arsenate coprecipitated with hydrous ferric oxide (HFO) was stabilized against dissolution during transformation of HFO to more crystalline iron (hydr)oxides. The rate of arsenate stabilization approximately coincided with the rate of HFO transformation at pH 6 and 40 ?C. Compa...

  8. Mechanism of selenite removal by a mixed adsorbent based on Fe-Mn hydrous oxides studied using X-ray absorption spectroscopy.

    PubMed

    Chubar, Natalia; Gerda, Vasyl; Szlachta, Małgorzata

    2014-11-18

    Selenium cycling in the environment is greatly controlled by various minerals, including Mn and Fe hydrous oxides. At the same time, such hydrous oxides are the main inorganic ion exchangers suitable (on the basis of their chemical nature) to sorb (toxic) anions, separating them from water solutions. The mechanism of selenite adsorption by the new mixed adsorbent composed of a few (amorphous and crystalline) phases [maghemite, MnCO3, and X-ray amorphous Fe(III) and Mn(III) hydrous oxides] was studied by extended X-ray absorption fine structure (EXAFS) spectroscopy [supported by Fourier transform infrared (FTIR) and X-ray diffraction (XRD) data]. The complexity of the porous adsorbent, especially the presence of the amorphous phases of Fe(III) and Mn(III) hydrous oxides, is the main reason for its high selenite removal performance demonstrated by batch and column adsorption studies shown in the previous work. Selenite was bound to the material via inner-sphere complexation (via oxygen) to the adsorption sites of the amorphous Fe(III) and Mn(III) oxides. This anion was attracted via bidentate binuclear corner-sharing coordination between SeO3(2-) trigonal pyramids and both FeO6 and MnO6 octahedra; however, the adsorption sites of Fe(III) hydrous oxides played a leading role in selenite removal. The contribution of the adsorption sites of Mn(III) oxide increased as the pH decreased from 8 to 6. Because most minerals have a complex structure (they are seldom based on individual substances) of various crystallinity, this work is equally relevant to environmental science and environmental technology because it shows how various solid phases control cycling of chemical elements in the environment.

  9. Formation of metallic and metal hydrous oxide dispersions

    NASA Technical Reports Server (NTRS)

    Matijevic, E.; Sapieszko, R. S.

    1979-01-01

    The formation, via hydrothermally induced precipitation from homogeneous solution, of a variety of well-defined dispersions of metallic and hydrous metal in the conditions under which the particles are produced (e.g., pH and composition of the growth medium, aging temperature, rate of heating, or degree of agitation) can be readily discerned by following changes in the mass, composition, and morphology of the final solid phase. The generation of colloidal dispersions in the absence of gravity convection or sedimentation effects may result in the appearance of morphological modifications not previously observed in terrestrially formed hydrosols.

  10. Phase composition analysis of hydrous aluminium oxides by thermal analysis and infrared spectrometry.

    PubMed

    Wittmann, Z; Kántor, E; Bélafi, K; Péterfy, L; Farkas, L P

    1992-12-01

    A general method for determination of the phase composition of hydrous aluminium oxides by thermal analysis and infrared spectrometry, and determination of the transformation temperature of mixtures of Al(OH)(3) and AlOOH into alpha-Al(2)O(3) are described.

  11. Rare earth element partitioning between hydrous ferric oxides and acid mine water during iron oxidation

    USGS Publications Warehouse

    Verplanck, P.L.; Nordstrom, D.K.; Taylor, H.E.; Kimball, B.A.

    2004-01-01

    Ferrous iron rapidly oxidizes to Fe (III) and precipitates as hydrous Fe (III) oxides in acid mine waters. This study examines the effect of Fe precipitation on the rare earth element (REE) geochemistry of acid mine waters to determine the pH range over which REEs behave conservatively and the range over which attenuation and fractionation occur. Two field studies were designed to investigate REE attenuation during Fe oxidation in acidic, alpine surface waters. To complement these field studies, a suite of six acid mine waters with a pH range from 1.6 to 6.1 were collected and allowed to oxidize in the laboratory at ambient conditions to determine the partitioning of REEs during Fe oxidation and precipitation. Results from field experiments document that even with substantial Fe oxidation, the REEs remain dissolved in acid, sulfate waters with pH below 5.1. Between pH 5.1 and 6.6 the REEs partitioned to the solid phases in the water column, and heavy REEs were preferentially removed compared to light REEs. Laboratory experiments corroborated field data with the most solid-phase partitioning occurring in the waters with the highest pH. ?? 2004 Elsevier Ltd. All rights reserved.

  12. Effect of competitive ions on the arsenic removal by mesoporous hydrous zirconium oxide from drinking water

    SciTech Connect

    Bortun, Anatoly; Bortun, Mila; Pardini, James; Khainakov, Sergei A.

    2010-11-15

    Adsorption properties of 302-type commercially available hydrous zirconium oxide (302-HZO) towards arsenic and some competitive anions and cations have been studied under batch and column conditions. Due to amphoteric properties, anion exchange performance of hydrous zirconium oxide is pH dependent. Media exhibits high affinity towards arsenic in a broad pH range, with high adsorption capacity at pH < 8. It was shown that silicate and phosphate ions are arsenic's main competitors affecting media adsorption capacity. Presence of transition metal cations in <1 ppm does not affect 302-HZO capacity on arsenic, whereas alkaline-earth cations improve arsenic removal. The possibility for significant increase of 302-HZO adsorption capacity on arsenic at pH > 8 by using 'solid acidifier' technique is discussed. Results of 302-HZO field trials are presented.

  13. Hydrous iron oxide modified diatomite as an active filtration medium for phosphate capture.

    PubMed

    Wang, Zhe; Lin, Yan; Wu, Deyi; Kong, Hainan

    2016-02-01

    A simple method to functionalize diatomite with hydrous iron oxide was attempted and its performance as a new active filtration material to remove and recover phosphate from water was investigated under varying solution conditions. The Langmuir phosphate adsorption capacity increased from 0.6 mgP/g for raw diatomite to 4.89, 14.71, 25.02 mgP/g for hydrous iron oxide modified diatomite (HIOMD), depending on the amount of iron loaded. Loading of hydrous iron oxide caused the increase in true and bulk density and a decline in filtration rate, but to a lesser extent. It was shown that the HIOMD product with suitable iron content could retain a good filtration performance with a greatly increased adsorption capacity for phosphate. The phosphate adsorption increased by decreasing pH and by increasing ionic strength at high pH levels. The adsorption process was interpreted by ligand exchange. Coexisting oxyanions of sulfate, nitrate, citrate, carbonate, silicate and humic acid showed different effects on phosphate fixation but it was presumed that their influence at their concentrations and pH levels commonly encountered in effluent or natural waters was limited, i.e., HIOMD had a reasonably good selectivity. Results in repeated adsorption, desorption and regeneration experiment showed that the adsorbed phosphate could be recovered and the material could be reused after regeneration. The column test showed that HIOMD could be potentially utilized as an adsorption filtration medium for phosphate removal and recovery from water.

  14. Hydrous pyrolysis/oxidation: in-ground thermal destruction of organic contaminants

    SciTech Connect

    Knauss, K. G.; Aines, R.D.; Dibley, M.J.; Leif, R.N.; Mew, D.A.

    1997-03-11

    Experimental work with organic solvents at Lawrence Livermore National Laboratory has suggested that in situ thermal oxidation of these compounds via hydrous pyrolysis forms the basis for a whole new remediation method, called hydrous pyrolysis oxidation. Preliminary results of hydrothermal oxidation using both dissolved 0{sub 2} gas and mineral oxidants present naturally in soils (e.g., MnO{sub 2}) demonstrate that TCE, TCA, and even PCE can be rapidly and completely degraded to benign products at moderate conditions, easily achieved in thermal remediation. Polycyclic aromatic hydrocarbons (PAHS) have an even larger thermodynamic driving force favoring oxidation, and they are also amenable to in situ destruction. Today, the principal treatment methods for chlorinated solvent- and PAH-contaminated soil are to remove it to landfills, or incinerate it on site. The most effective method for treating ground water, Dynamic Underground Stripping (Newmark et al., 1995), still involves removing the contaminant for destruction elsewhere. Hydrous pyrolysis/oxidation would eliminate the need for long-term use of expensive treatment facilities by converting all remaining contaminant to benign products (e.g., carbon dioxide, water, and chloride ion). The technique is expected to be applicable to dense non-aqueous phase liquids (DNAPLS) and dissolved organic components. Soil and ground water would be polished without bringing them to the surface. This would dramatically decrease the cost of final site closure efforts. Large-scale cleanup using hydrous pyrolysis/oxidation may cost less than $10/yd. The end product of hydrous pyrolysis/oxidation is expected to be a clean site. The delivery concept for hydrous pyrolysis/oxidation utilizes the established experience in heating large volumes of ground developed in the Dynamic Underground Stripping Demonstration (Newmark et al., 1995). Steam and possibly oxygen are injected together, building a heated, oxygenated zone in the

  15. Reactions of metal ions at surfaces of hydrous iron oxide

    USGS Publications Warehouse

    Hem, J.D.

    1977-01-01

    Cu, Ag and Cr concentrations in natural water may be lowered by mild chemical reduction involving ferric hydroxide-ferrous ion redox processes. V and Mo solubilities may be controlled by precipitation of ferrous vanadate or molybdate. Concentrations as low as 10-8.00 or 10-9.00 M are readily attainable for all these metals in oxygen-depleted systems that are relatively rich in Fe. Deposition of manganese oxides such as Mn3O4 can be catalyzed in oxygenated water by coupling to ferrous-ferric redox reactions. Once formed, these oxides may disproportionate, giving Mn4+ oxides. This reaction produces strongly oxidizing conditions at manganese oxide surfaces. The solubility of As is significantly influenced by ferric iron only at low pH. Spinel structures such as chromite or ferrites of Cu, Ni, and Zn, are very stable and if locally developed on ferric hydroxide surfaces could bring about solubilities much below 10-9.00 M for divalent metals near neutral pH. Solubilities calculated from thermodynamic data are shown graphically and compared with observed concentrations in some natural systems. ?? 1977.

  16. Use of metal hydrous titanium oxide catalysts to enhance coal tar yield via hydropyrolysis

    SciTech Connect

    Klavetter, E.A.; Stephens, H.P.; Dosch, R.G.

    1990-01-01

    Catalytic hydropyrolysis experiments performed in this project on several US and UK coals have established that tar yields in excess of 70% (daf basis) and conversions (100%-char) in excess of 80% can be achieved from bituminous coals containing 80--84% dmmf carbon using hydrous titanium oxide (HTO) catalysts with low concentrations of active metals. Total conversion approaches the reactive maceral contents for these coals. Previously performed two-stage catalytic hydropyrolysis experiments have demonstrated that high yields of liquid products with high H/C ratios, low heteroatom contents, and a significant concentration of light naphtha can be achieved. The objectives of this research are to determine suitable methods for catalyzing the hydropyrolysis process and to investigate the reactions and mechanisms responsible for the high conversion of coal materials to distillable liquids via direct catalytic hydropyrolysis. Recently developed hydrous titanium oxide (HTO)-supported catalysts have received encouraging results in direct coal liquefaction applications. Results of hydropyrolysis experiment using Mo and Pd HTO catalysts coated directly onto the coal are presented here and compared with results from experiments using uncatalyzed coal samples and using a dispersed MoS{sub 2} catalyst. The effect of coal rank, active metals concentration, dispersion method, and metal type are discussed. 9 refs., 6 figs., 2 tabs.

  17. Determination of Ideal Broth Formulations Needed to Prepare Hydrous Hafnium Oxide Microspheres via the Internal Gelation Process

    SciTech Connect

    Collins, Jack Lee; Hunt, Rodney Dale; Simmerman, S. G.

    2009-02-01

    A simple test-tube methodology was used to determine optimum process parameters for preparing hydrous hafnium oxide microspheres by the internal gelation process. Broth formulations of hafnyl chloride [HfOCl{sub 2}], hexamethylenetetramine, and urea were found that can be used to prepare hydrous hafnium oxide gel spheres in the temperature range of 70-90 C. A few gel-forming runs were made in which microspheres were prepared with some of these formulations in order to equate the test-tube gelation times with actual gelation times. These preparations confirmed that the test-tube methodology is reliable for determining the ideal broths.

  18. Determination of Ideal Broth Formulations Needed to Prepare Hydrous Aluminum Oxide Microspheres via the Internal Gelation Process

    SciTech Connect

    Collins, Jack Lee; Pye, S. L.

    2009-02-01

    A simple test-tube methodology was used to determine optimum process parameters for preparing hydrous aluminum oxide microspheres by the internal gelation process. Broth formulations of aluminum, hexamethylenetetramine, and urea were found that can be used to prepare hydrous aluminum oxide gel spheres in the temperature range of 60-90 C. A few gel-forming runs were made in which microspheres were prepared with some of these formulations in order to equate the test-tube gelation times with actual gelation times. These preparations confirmed that the test-tube methodology is reliable for determining the ideal broths.

  19. Hydrous pyrolysis/oxidation process for in situ destruction of chlorinated hydrocarbon and fuel hydrocarbon contaminants in water and soil

    DOEpatents

    Knauss, Kevin G.; Copenhaver, Sally C.; Aines, Roger D.

    2000-01-01

    In situ hydrous pyrolysis/oxidation process is useful for in situ degradation of hydrocarbon water and soil contaminants. Fuel hydrocarbons, chlorinated hydrocarbons, polycyclic aromatic hydrocarbons, petroleum distillates and other organic contaminants present in the soil and water are degraded by the process involving hydrous pyrolysis/oxidation into non-toxic products of the degradation. The process uses heat which is distributed through soils and water, optionally combined with oxygen and/or hydrocarbon degradation catalysts, and is particularly useful for remediation of solvent, fuel or other industrially contaminated sites.

  20. Formation of Green Rust and Immobilization of Nickel in Response to Bacterial Reduction of Hydrous Ferric Oxide

    SciTech Connect

    Parmar, N.; Gorby, Yuri A.; Beveridge, Terrance J.; Ferris, F G.

    2001-04-01

    This investigation documents the formation of Green Rust (GR) and immobilization of Ni2+ in response to bacterial reduction of hydrous ferric oxide (HFO) reduction experiments provided evidence that the solid-phase partitioning of Ni2+ in GR extended from equilibrium solid-solution behavior.

  1. Effect of hot pressing additives on the leachability of hot pressed sodium hydrous titanium oxide

    SciTech Connect

    Valentine, T.M.; Sambell, R.A.J.

    1980-01-01

    Sodium hydrous titanium oxide is an ion exchange resin which can be used for immobilizing medium level waste (MLW) liquors. When hot pressed, it undergoes conversion to a ceramic. Three low melting point materials (borax, bismuth trioxide, and a mixture of PbO/CuO) were added to the (Na)HTiO and the effect that each of these had on aiding densification was assessed. Hot pressing temperature, applied pressure, and percentage addition of hot pressing aid were varied. Percentage open porosity, flexural strength, and leachability were measured. There was a linear relationship between the percentage open porosity and the logarithm of the leach rate for a constant percentage addition of each additive.

  2. In situ destruction of contaminants via hydrous pyrolysis/oxidation. Visalia Field Test

    SciTech Connect

    Newmark, Robin L.; Aines, Roger D.; Knauss, Kevin; Leif, Roald; Chiarappa, Marina; Hudson, Bryant; Carrigan, Charles; Tompson, Andy; Richards, Jim; Eaker, Craig; Weidner, Randall; Sciarotta, Terry

    1998-12-01

    A field test of hydrous pyrolysis/oxidation (HPO) was conducted during the summer of 1997, during a commercial application of thermal remediation (Dynamic Underground Stripping (DUS)) at the Visalia Pole Yard (a super-fund site) in southern California. At Visalia, Southern California Edison Co. is applying the DUS thermal remediation method to clean up a large (4.3 acre) site contaminated with pole-treating compounds. This is a full-scale cleanup, during which initial extraction of contaminants is augmented by combined steam/air injection in order to enhance the destruction of residual contaminants by HPO. Laboratory results indicate that the contaminants at Visaha react at similar rates to TCE, which has been the focus of extensive laboratory work (Knauss et al., 1998a-c). Field experimental results from this application yield valuable information (1) confirming the destruction of contaminants in soil and groundwater by HPO, (2) validating the predictive models used to design HP0 steam injection systems, (3) demonstrating that accurate field measurements of the critical fluid parameters can be obtained using existing monitoring wells and (4) obtaining a reasonable prediction of the cost and effectiveness of HPO, working at a commercial scale and with commercial partners. The goal of our additional study and demonstration in conjunction with Edison has been to obtain early proof of hydrous pyrolysis/oxidation in the field, and validate our predictive models and monitoring strategies. This demonstration provides valuable economic and practicability data obtained on a commercial scale, with more detailed field validation than is commonly available on a commercially-conducted cleanup. The results of LLNL' s field experiments constrain the destruction rates throughout the site, and enable site management to make accurate estimates of total in situ destruction based on the recovered carbon. As of October, 1998, over 900,000 lb of contaminant have been removed from the

  3. Mass production of two-dimensional oxides by rapid heating of hydrous chlorides

    NASA Astrophysics Data System (ADS)

    Zhao, Chunsong; Zhang, Haitian; Si, Wenjie; Wu, Hui

    2016-09-01

    Two-dimensional (2D) nanoscale oxides have attracted research interest owing to their electronic, magnetic optical and catalytic properties. If they could be manufactured on a large scale, 2D oxides would be attractive for applications ranging from electronics to energy conversion and storage. Herein, we report facile fabrication of oxide nanosheets by rapid thermal annealing of corresponding hydrous-chloride compounds. By heating CrCl3.6H2O, ZrOCl2.8H2O, AlCl3.6H2O and YCl3.6H2O crystals as precursors, we immediately collect large quantities of ultrathin Cr2O3, ZrO2, Al2O3 and Y2O3 nanosheets, respectively. The formation of layered nanosheets relies on exfoliation driven by rapid evaporation of water and/or other gas molecules generated under annealing. Our route allows simple, efficient and inexpensive production of 2D oxides. As a demonstration, we evaluate Cr2O3 nanosheets prepared by our method as anodes in lithium-ion batteries and find superior performance in comparison with their microcrystalline counterparts.

  4. Mass production of two-dimensional oxides by rapid heating of hydrous chlorides.

    PubMed

    Zhao, Chunsong; Zhang, Haitian; Si, Wenjie; Wu, Hui

    2016-01-01

    Two-dimensional (2D) nanoscale oxides have attracted research interest owing to their electronic, magnetic optical and catalytic properties. If they could be manufactured on a large scale, 2D oxides would be attractive for applications ranging from electronics to energy conversion and storage. Herein, we report facile fabrication of oxide nanosheets by rapid thermal annealing of corresponding hydrous-chloride compounds. By heating CrCl3·6H2O, ZrOCl2·8H2O, AlCl3·6H2O and YCl3·6H2O crystals as precursors, we immediately collect large quantities of ultrathin Cr2O3, ZrO2, Al2O3 and Y2O3 nanosheets, respectively. The formation of layered nanosheets relies on exfoliation driven by rapid evaporation of water and/or other gas molecules generated under annealing. Our route allows simple, efficient and inexpensive production of 2D oxides. As a demonstration, we evaluate Cr2O3 nanosheets prepared by our method as anodes in lithium-ion batteries and find superior performance in comparison with their microcrystalline counterparts. PMID:27610589

  5. Mass production of two-dimensional oxides by rapid heating of hydrous chlorides

    PubMed Central

    Zhao, Chunsong; Zhang, Haitian; Si, Wenjie; Wu, Hui

    2016-01-01

    Two-dimensional (2D) nanoscale oxides have attracted research interest owing to their electronic, magnetic optical and catalytic properties. If they could be manufactured on a large scale, 2D oxides would be attractive for applications ranging from electronics to energy conversion and storage. Herein, we report facile fabrication of oxide nanosheets by rapid thermal annealing of corresponding hydrous-chloride compounds. By heating CrCl3·6H2O, ZrOCl2·8H2O, AlCl3·6H2O and YCl3·6H2O crystals as precursors, we immediately collect large quantities of ultrathin Cr2O3, ZrO2, Al2O3 and Y2O3 nanosheets, respectively. The formation of layered nanosheets relies on exfoliation driven by rapid evaporation of water and/or other gas molecules generated under annealing. Our route allows simple, efficient and inexpensive production of 2D oxides. As a demonstration, we evaluate Cr2O3 nanosheets prepared by our method as anodes in lithium-ion batteries and find superior performance in comparison with their microcrystalline counterparts. PMID:27610589

  6. Preloading hydrous ferric oxide into granular activated carbon for arsenic removal.

    PubMed

    Jang, Min; Chen, Weifang; Cannon, Fred S

    2008-05-01

    Arsenic is of concern in water treatment because of its health effects. This research focused on incorporating hydrous ferric oxide (HFO) into granular activated carbon (GAC) for the purpose of arsenic removal. Iron was incorporated into GAC via incipient wetness impregnation and cured at temperatures ranging from 60 to 90 degrees C. X-ray diffractions and arsenic sorption as a function of pH were conducted to investigate the effect of temperature on final iron oxide (hydroxide) and their arsenic removal capabilities. Results revealed that when curing at 60 degrees C, the procedure successfully created HFO in the pores of GAC, whereas at temperatures of 80 and 90 degrees C, the impregnated iron oxide manifested a more crystalline form. In the column tests using synthetic water, the HFO-loaded GAC prepared at 60 degrees C also showed higher sorption capacities than media cured at higher temperatures. These results indicated that the adsorption capacity for arsenic was closely related to the form of iron (hydr)oxide for a given iron content For the column test using a natural groundwater, HFO-loaded GAC (Fe, 11.7%) showed an arsenic sorption capacity of 26 mg As/g when the influent contained 300 microg/L As. Thus, the preloading of HFO into a stable GAC media offered the opportunity to employ fixed carbon bed reactors in water treatment plants or point-of-use filters for arsenic removal. PMID:18522120

  7. Modeling sorption of divalent metal cations on hydrous manganese oxide using the diffuse double layer model

    USGS Publications Warehouse

    Tonkin, J.W.; Balistrieri, L.S.; Murray, J.W.

    2004-01-01

    Manganese oxides are important scavengers of trace metals and other contaminants in the environment. The inclusion of Mn oxides in predictive models, however, has been difficult due to the lack of a comprehensive set of sorption reactions consistent with a given surface complexation model (SCM), and the discrepancies between published sorption data and predictions using the available models. The authors have compiled a set of surface complexation reactions for synthetic hydrous Mn oxide (HMO) using a two surface site model and the diffuse double layer SCM which complements databases developed for hydrous Fe (III) oxide, goethite and crystalline Al oxide. This compilation encompasses a range of data observed in the literature for the complex HMO surface and provides an error envelope for predictions not well defined by fitting parameters for single or limited data sets. Data describing surface characteristics and cation sorption were compiled from the literature for the synthetic HMO phases birnessite, vernadite and ??-MnO2. A specific surface area of 746 m2g-1 and a surface site density of 2.1 mmol g-1 were determined from crystallographic data and considered fixed parameters in the model. Potentiometric titration data sets were adjusted to a pH1EP value of 2.2. Two site types (???XOH and ???YOH) were used. The fraction of total sites attributed to ???XOH (??) and pKa2 were optimized for each of 7 published potentiometric titration data sets using the computer program FITEQL3.2. pKa2 values of 2.35??0.077 (???XOH) and 6.06??0.040 (???YOH) were determined at the 95% confidence level. The calculated average ?? value was 0.64, with high and low values ranging from 1.0 to 0.24, respectively. pKa2 and ?? values and published cation sorption data were used subsequently to determine equilibrium surface complexation constants for Ba2+, Ca2+, Cd 2+, Co2+, Cu2+, Mg2+, Mn 2+, Ni2+, Pb2+, Sr2+ and Zn 2+. In addition, average model parameters were used to predict additional

  8. Oxidative stress by inorganic nanoparticles.

    PubMed

    Tee, Jie Kai; Ong, Choon Nam; Bay, Boon Huat; Ho, Han Kiat; Leong, David Tai

    2016-05-01

    Metallic and metallic oxide nanoparticles (NPs) have been increasingly used for various bio-applications owing to their unique physiochemical properties in terms of conductivity, optical sensitivity, and reactivity. With the extensive usage of NPs, increased human exposure may cause oxidative stress and lead to undesirable health consequences. To date, various endogenous and exogenous sources of oxidants contributing to oxidative stress have been widely reported. Oxidative stress is generally defined as an imbalance between the production of oxidants and the activity of antioxidants, but it is often misrepresented as a single type of cellular stress. At the biological level, NPs can initiate oxidative stress directly or indirectly through various mechanisms, leading to profound effects ranging from the molecular to the disease level. Such effects of oxidative stress have been implicated owing to their small size and high biopersistence. On the other hand, cellular antioxidants help to counteract oxidative stress and protect the cells from further damage. While oxidative stress is commonly known to exert negative biological effects, measured and intentional use of NPs to induce oxidative stress may provide desirable effects to either stimulate cell growth or promote cell death. Hence, NP-induced oxidative stress can be viewed from a wide paradigm. Because oxidative stress is comprised of a wide array of factors, it is also important to use appropriate assays and methods to detect different pro-oxidant and antioxidant species at molecular and disease levels. WIREs Nanomed Nanobiotechnol 2016, 8:414-438. doi: 10.1002/wnan.1374 For further resources related to this article, please visit the WIREs website.

  9. Oxidative stress by inorganic nanoparticles.

    PubMed

    Tee, Jie Kai; Ong, Choon Nam; Bay, Boon Huat; Ho, Han Kiat; Leong, David Tai

    2016-05-01

    Metallic and metallic oxide nanoparticles (NPs) have been increasingly used for various bio-applications owing to their unique physiochemical properties in terms of conductivity, optical sensitivity, and reactivity. With the extensive usage of NPs, increased human exposure may cause oxidative stress and lead to undesirable health consequences. To date, various endogenous and exogenous sources of oxidants contributing to oxidative stress have been widely reported. Oxidative stress is generally defined as an imbalance between the production of oxidants and the activity of antioxidants, but it is often misrepresented as a single type of cellular stress. At the biological level, NPs can initiate oxidative stress directly or indirectly through various mechanisms, leading to profound effects ranging from the molecular to the disease level. Such effects of oxidative stress have been implicated owing to their small size and high biopersistence. On the other hand, cellular antioxidants help to counteract oxidative stress and protect the cells from further damage. While oxidative stress is commonly known to exert negative biological effects, measured and intentional use of NPs to induce oxidative stress may provide desirable effects to either stimulate cell growth or promote cell death. Hence, NP-induced oxidative stress can be viewed from a wide paradigm. Because oxidative stress is comprised of a wide array of factors, it is also important to use appropriate assays and methods to detect different pro-oxidant and antioxidant species at molecular and disease levels. WIREs Nanomed Nanobiotechnol 2016, 8:414-438. doi: 10.1002/wnan.1374 For further resources related to this article, please visit the WIREs website. PMID:26359790

  10. Inorganic chemistry: Deconstructing water oxidation

    NASA Astrophysics Data System (ADS)

    Cook, Sarah A.; Borovik, A. S.

    2013-04-01

    During photosynthesis, the oxygen-evolving complex oxidizes water to produce molecular oxygen. Now, a possible role for the calcium ion in this complex has been proposed based on the electrochemical properties of a series of synthetic heterometallic clusters.

  11. Determination of Ideal Broth Formulations Needed to Prepare Hydrous Cerium Oxide Microspheres via the Internal Gelation Process

    SciTech Connect

    Collins, Jack Lee; Chi, Anthony

    2009-02-01

    A simple test tube methodology was used to determine optimum process parameters for preparing hydrous cerium oxide microspheres via the internal gelation process.1 Broth formulations of cerium ammonium nitrate [(NH4)2Ce(NO3)6], hexamethylenetetramine, and urea were found that can be used to prepare hydrous cerium oxide gel spheres in the temperature range of 60 to 90 C. A few gel-forming runs were made in which microspheres were prepared with some of these formulations to be able to equate the test-tube gelation times to actual gelation times. These preparations confirmed that the test-tube methodology is reliable for determining the ideal broth formulations.

  12. ATR-FTIR spectroscopic studies of boric acid adsorption on hydrous ferric oxide

    NASA Astrophysics Data System (ADS)

    Peak, Derek; Luther, George W.; Sparks, Donald L.

    2003-07-01

    Boron is an important micronutrient for plants, but high B levels in soils are often responsible for toxicity effects in plants. It is therefore important to understand reactions that may affect B availability in soils. In this study, Attenuated Total Reflectance Fourier transform Infrared (ATR-FTIR) spectroscopy was employed to investigate mechanisms of boric acid (B(OH) 3) and borate (B(OH) 4-) adsorption on hydrous ferric oxide (HFO). On the HFO surface, boric acid adsorbs via both physical adsorption (outer-sphere) and ligand exchange (inner-sphere) reactions. Both trigonal (boric acid) and tetrahedral (borate) boron are complexed on the HFO surface, and a mechanism where trigonal boric acid in solution reacts to form either trigonal or tetrahedral surface complexes is proposed based upon the spectroscopic results. The presence of outer-sphere boric acid complexes can be explained based on the Lewis acidity of the B metal center, and this complex has important implications for boron transport and availability. Outer-sphere boric acid is more likely to leach downward in soils in response to water flow. Outer-sphere boron would also be expected to be more available for plant uptake than more strongly bound boron complexes, and may more readily return to the soil solution when solution concentrations decrease.

  13. The effect of solids residence time on phosphorus adsorption to hydrous ferric oxide floc.

    PubMed

    Conidi, Daniela; Parker, Wayne J

    2015-11-01

    The impact of solids residence time (SRT) on phosphate adsorption to hydrous ferric oxide (HFO) floc when striving for ultra-low P concentrations was characterized and an equilibrium model that describes the adsorption of P onto HFO floc of different ages was developed. The results showed that fresh HFO had a higher adsorption capacity in comparison to aged (2.8, 7.4, 10.8 and 22.8 days) HFO and contributed substantially to P removal at steady state. P adsorption onto HFO solids was determined to be best described by the Freundlich isotherm. P desorption from HFO solids was negligible supporting the hypothesis that chemisorption is the mechanism of P adsorption on HFO solids. A model that included the contribution of different classes of HFO solids (i.e. High, Low or Old, containing high concentration, low concentration or no active surface sites, respectively) to adsorption onto HFO from a sequencing batch reactor (SBR) system was found to adequately describe P adsorption onto HFO solids of different ages. From the model it was determined that the fractions of High and Low HFO decreased with SRT while the fraction of Old HFO increased with SRT. The transformation of High HFO to Low HFO did not limit the overall production of Old HFO and the fresh HFO solids contributed more to P removal at steady state than the aged solids.

  14. Enhanced removal of fluoride by polystyrene anion exchanger supported hydrous zirconium oxide nanoparticles.

    PubMed

    Pan, Bingcai; Xu, Jingsheng; Wu, Bing; Li, Zhigang; Liu, Xitong

    2013-08-20

    Here we fabricated a novel nanocomposite HZO-201, an encapsulated nanosized hydrous zirconium oxide (HZO) within a commercial porous polystyrene anion exchanger D201, for highly efficient defluoridation of water. HZO-201 exhibited much higher preference than activated alumina and D201 toward fluoride removal when competing anions (chloride, sulfate, nitrate, and bicarbonate) coexisted at relatively high levels. Fixed column adsorption indicated that the effective treatable volume of water with HZO-201 was about 7-14 times as much as with D201 irrespective of whether synthetic solution or groundwater was the feeding solution. In addition, HZO-201 could treat >3000 BV of the acidic effluent (around 3.5 mg F(-)/L) per run at pH 3.5, compared to only ∼4 BV with D201. The exhausted HZO-201 could be regenerated by NaOH solution for repeated use without any significant capacity loss. Such attractive performance of HZO-201 resulted from its specific hybrid structure, that is, the host anion exchanger D201 favors the preconcentration of fluoride ions inside the polymer based on the Donnan principle, and the encapsulated nanosized HZO exhibits preferable sequestration of fluoride through specific interaction, as further demonstrated by XPS spectra. The influence of solution pH, competitive anions, and contact time was also examined. The results suggested that HZO-201 has a great potential in efficient defluoridation of groundwater and acidic mine drainage.

  15. Preferable removal of phosphate from water using hydrous zirconium oxide-based nanocomposite of high stability.

    PubMed

    Chen, Liang; Zhao, Xin; Pan, Bingcai; Zhang, Weixian; Hua, Ming; Lv, Lu; Zhang, Weiming

    2015-03-01

    In this study, we employed a new nanocomposite adsorbent HZO-201, which featured high stability under varying solution chemistry, for preferable removal of phosphate from synthetic solution and a real effluent. An anion exchange resin (D-201) was employed as the host of HZO-201, where nano-hydrous zirconium oxide (HZO) was encapsulated as the active species. D-201 binds phosphate through nonspecific electrostatic affinity, whereas the loaded HZO nanoparticles capture phosphate through formation of the inner-sphere complexes. Quantitative contribution of both species to phosphate adsorption was predicted based on the double-Langmuir model. Preferable removal of phosphate by HZO-201 was observed in the presence of the competing anions at higher levels (Cl(-), NO3(-), SO4(2-), HCO3(-)). Fixed-bed adsorption indicated that the effective volume capacity of a synthetic water (2.0 mg P-PO4(3-)/L) by using HZO-201 was ∼1600 BV in the first run (<0.5mg P-PO4(3-)/L), comparable to Fe(III)-based nanocomposite HFO-201 (∼1500 BV) and much larger than D-201 (<250 BV). The exhausted HZO-201 can be in situ regenerated by using a binary NaOH-NaCl solution for cyclic runs, whether fed with the synthetic solution or real effluent. In general, HZO-201 is a promising alternative to Fe(III)-based adsorbents for trace phosphate removal from effluent particularly at acidic pH.

  16. Fabrication of a Biomass-Based Hydrous Zirconium Oxide Nanocomposite for Preferable Phosphate Removal and Recovery.

    PubMed

    Qiu, Hui; Liang, Chen; Zhang, Xiaolin; Chen, Mindong; Zhao, Yunxia; Tao, Tao; Xu, Zhengwen; Liu, Gang

    2015-09-23

    Advanced removal of phosphate by low-cost adsorbents from municipal wastewater or industrial effluents is an effective and economic way to prevent the occurrence of eutrophication. Here, we proposed a novel method to immobilize hydrous zirconium oxide nanoparticle within quaternary-aminated wheat straw, and obtained an inexpensive, eco-friendly nanocomposite Ws-N-Zr. The biomass-based Ws-N-Zr exhibited higher preference toward phosphate than commercial anion exchanger IRA-900 when competing sulfate ions coexisted at relatively high levels. Such excellent performance of Ws-N-Zr resulted from its specific hybrid structure, the quaternary ammonium groups bonded on the host favor the preconcentration of phosphate ions inside the wheat straw based on Donnan effect, and the encapsulated HZO nanoparticle exhibits preferable sequestration of phosphate ions through specific interaction, as further demonstrated by FTIR and X-ray photoelectron spectroscopy. Cycle adsorption and regeneration experiments demonstrated that Ws-N-Zr could be employed for repeated use without significant capacity loss, when the binary NaOH-NaCl solution was employed as the regenerant. The influence of solution pH and contact time was also examined. The results suggested that Ws-N-Zr has a great potential in efficient removal of phosphate in contaminated waters.

  17. Hydrous ferric oxide doped alginate beads for fluoride removal: Adsorption kinetics and equilibrium studies

    NASA Astrophysics Data System (ADS)

    Sujana, M. G.; Mishra, A.; Acharya, B. C.

    2013-04-01

    A new biopolymer beads, composite of hydrous ferric oxide (HFO) and alginate were synthesised, characterised and studied for its fluoride efficiency from water. The beads were characterised by chemical analysis, BET surface area, pHPZC and X-ray diffraction (XRD) analysis. The optimum conditions for fluoride removal were determined by studying operational variables viz. pH, contact time, initial F- concentration, bead dose and temperature. Presence of other anions like SO42-, PO43-, NO3-, Cl- and HCO3- effect on fluoride removal efficiency of prepared beads was also tested. The beads were 0.8-0.9 mm in size and contain 32-33% Fe (III) and showed specific surface area of 25.80 m2 g-1 and pHPZC of 5.15. Modified beads demonstrated Langmuir F- adsorption capacity of 8.90 mg g-1 at pH 7.0. The adsorption kinetics were best described by the pseudo-second order kinetic model followed by intra-particle diffusion as the rate determining step. It was found that about 80% of the adsorbed fluoride could be desorbed by using 0.05 M HCl. The FTIR, Raman and SEM-EDAX analysis were used to study the fluoride adsorption mechanisms on beads. Studies were also conducted to test the potential application of beads for F- removal from drinking water and the treated water quality.

  18. Enhanced removal of fluoride by polystyrene anion exchanger supported hydrous zirconium oxide nanoparticles.

    PubMed

    Pan, Bingcai; Xu, Jingsheng; Wu, Bing; Li, Zhigang; Liu, Xitong

    2013-08-20

    Here we fabricated a novel nanocomposite HZO-201, an encapsulated nanosized hydrous zirconium oxide (HZO) within a commercial porous polystyrene anion exchanger D201, for highly efficient defluoridation of water. HZO-201 exhibited much higher preference than activated alumina and D201 toward fluoride removal when competing anions (chloride, sulfate, nitrate, and bicarbonate) coexisted at relatively high levels. Fixed column adsorption indicated that the effective treatable volume of water with HZO-201 was about 7-14 times as much as with D201 irrespective of whether synthetic solution or groundwater was the feeding solution. In addition, HZO-201 could treat >3000 BV of the acidic effluent (around 3.5 mg F(-)/L) per run at pH 3.5, compared to only ∼4 BV with D201. The exhausted HZO-201 could be regenerated by NaOH solution for repeated use without any significant capacity loss. Such attractive performance of HZO-201 resulted from its specific hybrid structure, that is, the host anion exchanger D201 favors the preconcentration of fluoride ions inside the polymer based on the Donnan principle, and the encapsulated nanosized HZO exhibits preferable sequestration of fluoride through specific interaction, as further demonstrated by XPS spectra. The influence of solution pH, competitive anions, and contact time was also examined. The results suggested that HZO-201 has a great potential in efficient defluoridation of groundwater and acidic mine drainage. PMID:23909842

  19. Preferable removal of phosphate from water using hydrous zirconium oxide-based nanocomposite of high stability.

    PubMed

    Chen, Liang; Zhao, Xin; Pan, Bingcai; Zhang, Weixian; Hua, Ming; Lv, Lu; Zhang, Weiming

    2015-03-01

    In this study, we employed a new nanocomposite adsorbent HZO-201, which featured high stability under varying solution chemistry, for preferable removal of phosphate from synthetic solution and a real effluent. An anion exchange resin (D-201) was employed as the host of HZO-201, where nano-hydrous zirconium oxide (HZO) was encapsulated as the active species. D-201 binds phosphate through nonspecific electrostatic affinity, whereas the loaded HZO nanoparticles capture phosphate through formation of the inner-sphere complexes. Quantitative contribution of both species to phosphate adsorption was predicted based on the double-Langmuir model. Preferable removal of phosphate by HZO-201 was observed in the presence of the competing anions at higher levels (Cl(-), NO3(-), SO4(2-), HCO3(-)). Fixed-bed adsorption indicated that the effective volume capacity of a synthetic water (2.0 mg P-PO4(3-)/L) by using HZO-201 was ∼1600 BV in the first run (<0.5mg P-PO4(3-)/L), comparable to Fe(III)-based nanocomposite HFO-201 (∼1500 BV) and much larger than D-201 (<250 BV). The exhausted HZO-201 can be in situ regenerated by using a binary NaOH-NaCl solution for cyclic runs, whether fed with the synthetic solution or real effluent. In general, HZO-201 is a promising alternative to Fe(III)-based adsorbents for trace phosphate removal from effluent particularly at acidic pH. PMID:25463215

  20. Study on sulfadimethoxine removal from aqueous solutions by hydrous ferric oxides.

    PubMed

    Zhu, Weixiao; Wang, Jianduo; Wang, Yili; Wang, Hongjie

    2016-01-01

    Significant concerns have been raised over the presence of antibiotics including sulfadimethoxine (SDMO) in aquatic environments. This study investigated the removal capability and mechanism involved in the removal of SDMO by hydrous ferric oxides (HFO). Results showed that SDMO removal was highly pH and ionic strength dependent. The pseudo-first-order model fitted well the kinetic results, and the value of the calculated activation energy for SDMO adsorption onto HFO was 8.6 kJ mol(-1). Adsorption isotherms at varied temperatures were well described by the Langmuir model. Thermodynamic parameters (change in enthalpy > 0, change in entropy > 0, and change in Gibbs free energy < 0) calculated from the temperature-dependent sorption data revealed spontaneous and endothermic process. The exchange of the surface hydroxyl groups of HFO and the negative anions of SDMO(-) and the electrostatic interaction between the positively charged surface of HFO and the deprotonated imino (-N(-)-) accounted for the uptake of SDMO by HFO. PMID:27642833

  1. Fabrication of a Biomass-Based Hydrous Zirconium Oxide Nanocomposite for Preferable Phosphate Removal and Recovery.

    PubMed

    Qiu, Hui; Liang, Chen; Zhang, Xiaolin; Chen, Mindong; Zhao, Yunxia; Tao, Tao; Xu, Zhengwen; Liu, Gang

    2015-09-23

    Advanced removal of phosphate by low-cost adsorbents from municipal wastewater or industrial effluents is an effective and economic way to prevent the occurrence of eutrophication. Here, we proposed a novel method to immobilize hydrous zirconium oxide nanoparticle within quaternary-aminated wheat straw, and obtained an inexpensive, eco-friendly nanocomposite Ws-N-Zr. The biomass-based Ws-N-Zr exhibited higher preference toward phosphate than commercial anion exchanger IRA-900 when competing sulfate ions coexisted at relatively high levels. Such excellent performance of Ws-N-Zr resulted from its specific hybrid structure, the quaternary ammonium groups bonded on the host favor the preconcentration of phosphate ions inside the wheat straw based on Donnan effect, and the encapsulated HZO nanoparticle exhibits preferable sequestration of phosphate ions through specific interaction, as further demonstrated by FTIR and X-ray photoelectron spectroscopy. Cycle adsorption and regeneration experiments demonstrated that Ws-N-Zr could be employed for repeated use without significant capacity loss, when the binary NaOH-NaCl solution was employed as the regenerant. The influence of solution pH and contact time was also examined. The results suggested that Ws-N-Zr has a great potential in efficient removal of phosphate in contaminated waters. PMID:26340586

  2. Hydrous ruthenium oxide nanoparticles anchored to graphene and carbon nanotube hybrid foam for supercapacitors

    SciTech Connect

    Wang, Wei; Guo, S.; Lee, I.; Ahmed, K.; Zhong, J.; Favors, Z.; Zaera, F.; Ozkan, M.; Ozkan, C. S

    2014-03-25

    In real life applications, supercapacitors (SCs) often can only be used as part of a hybrid system together with other high energy storage devices due to their relatively lower energy density in comparison to other types of energy storage devices such as batteries and fuel cells. Increasing the energy density of SCs will have a huge impact on the development of future energy storage devices by broadening the area of application for SCs. Here, we report a simple and scalable way of preparing a three-dimensional (3D) sub-5 nm hydrous ruthenium oxide (RuO₂) anchored graphene and CNT hybrid foam (RGM) architecture for high-performance supercapacitor electrodes. This RGM architecture demonstrates a novel graphene foam conformally covered with hybrid networks of RuO₂ nanoparticles and anchored CNTs. SCs based on RGM show superior gravimetric and per-area capacitive performance (specific capacitance: 502.78 F g⁻¹, areal capacitance: 1.11 F cm⁻²) which leads to an exceptionally high energy density of 39.28 Wh kg⁻¹ and power density of 128.01 kW kg⁻¹. The electrochemical stability, excellent capacitive performance, and the ease of preparation suggest this RGM system is promising for future energy storage applications.

  3. Hydrous Ruthenium Oxide Nanoparticles Anchored to Graphene and Carbon Nanotube Hybrid Foam for Supercapacitors

    PubMed Central

    Wang, Wei; Guo, Shirui; Lee, Ilkeun; Ahmed, Kazi; Zhong, Jiebin; Favors, Zachary; Zaera, Francisco; Ozkan, Mihrimah; Ozkan, Cengiz S.

    2014-01-01

    In real life applications, supercapacitors (SCs) often can only be used as part of a hybrid system together with other high energy storage devices due to their relatively lower energy density in comparison to other types of energy storage devices such as batteries and fuel cells. Increasing the energy density of SCs will have a huge impact on the development of future energy storage devices by broadening the area of application for SCs. Here, we report a simple and scalable way of preparing a three-dimensional (3D) sub-5 nm hydrous ruthenium oxide (RuO2) anchored graphene and CNT hybrid foam (RGM) architecture for high-performance supercapacitor electrodes. This RGM architecture demonstrates a novel graphene foam conformally covered with hybrid networks of RuO2 nanoparticles and anchored CNTs. SCs based on RGM show superior gravimetric and per-area capacitive performance (specific capacitance: 502.78 F g−1, areal capacitance: 1.11 F cm−2) which leads to an exceptionally high energy density of 39.28 Wh kg−1 and power density of 128.01 kW kg−1. The electrochemical stability, excellent capacitive performance, and the ease of preparation suggest this RGM system is promising for future energy storage applications. PMID:24663242

  4. Arsenic removal using hydrous nanostructure iron(III)-titanium(IV) binary mixed oxide from aqueous solution.

    PubMed

    Gupta, Kaushik; Ghosh, Uday Chand

    2009-01-30

    The synthetic bimetal iron(III)-titanium(IV) oxide (NHITO) used was characterized as hydrous and nanostructured mixed oxide, respectively, by the Föurier transform infra red (FTIR), X-ray diffraction (XRD) pattern and the transmission electron microscopic (TEM) image analyses. Removal of As(III) and As(V) using the NHITO was studied at pH 7.0 (+/-0.1) with variation of contact time, solute concentration and temperature. The kinetic sorption data, in general, for As(III) described the pseudo-first order while that for As(V) described the pseudo-second order equation. The Langmuir isotherm described the equilibrium data (303 (+/-1.6)K) of fit was well with the Langmuir model. The Langmuir capacity (q(m), mg g(-1)) value of the material is 85.0 (+/-4.0) and 14.0 (+/-0.5), respectively, for the reduced and oxidized species. The sorption reactions on NHITO were found to be endothermic and spontaneous, and took place with increasing entropy. The energy (kJ mol(-1)) of sorption for As(III) and As(V) estimated, respectively, is 9.09 (+/-0.01) and 13.51 (+/-0.04). The sorption percentage reduction of As(V) was significant while that of As(III) was insignificant in presence of phosphate and sulfate. The fixed bed NHITO column (5.1 cm x 1.0 cm) sorption tests gave 3.0, 0.7 and 4.5L treated water (As content < or = 0.01 mg L(-1)) from separate As(III) and As(V) spiked (0.35+/-0.02 mg L(-1)) natural water samples and from high arsenic (0.11+/-0.01 mg L(-1)) ground water, respectively when inflow rate was (0.06 L h(-1)).

  5. Arsenate sorption by hydrous ferric oxide incorporated onto granular activated carbon with phenol formaldehyde resins coating.

    PubMed

    Zhuang, J M; Hobenshield, E; Walsh, T

    2008-04-01

    A simple and effective method was developed using phenol formaldehyde (PF) resins to immobilize hydrous ferric oxide (HFO) onto granular activated carbon (GAC). The resulting sorbent possesses advantages for both the ferric oxide and the GAC, such as a great As-affinity of ferric oxide, large surface area of GAC, and enhanced physical strength. The studies showed that within one hour this sorbent was able to remove 85% of As(V) from water containing an initial As(V) concentration of 1.74 mg l(-1). The As(V) adsorption onto the sorbent was found to follow a pseudo-second order kinetics model. The adsorption isotherms were interpreted in terms of the Langmuir and Freundlich models. The equilibrium data fitted very well to both models. Column tests showed that this sorbent was able to achieve residual concentrations of As(V) in a range of 0.1-2.0 microg l(-1) while continuously treating about 180 bed volume (BV, 130 ml-BV) of arsenate water with an initial As(V) concentration of 1886 microg l(-1) at a filtration rate of 13.5 ml min(-1), i.e., an empty bed contact time (EBCT) of 9.6 min and a gram sorbent contact time (GSCT) of 0.15 min. After passing 635 BV of arsenate water, the exhausted sorbent was then tested by the Toxicity Characteristic Leaching Procedure (TCLP, US EPA Method 1311) test, and classified as non-hazardous for disposal. Hence, this HFO-PF-coated GAC has the capability to remove As(V) from industrial wastewater containing As(V) levels of about 2 mg l(-1). PMID:18619145

  6. New strategy to enhance phosphate removal from water by hydrous manganese oxide.

    PubMed

    Pan, Bingcai; Han, Feichao; Nie, Guangze; Wu, Bing; He, Kai; Lu, Lv

    2014-05-01

    Hydrous manganese oxide (HMO) is generally negatively charged at circumneutral pH and cannot effectively remove anionic pollutants such as phosphate. Here we proposed a new strategy to enhance HMO-mediated phosphate removal by immobilizing nano-HMO within a polystyrene anion exchanger (NS). The resultant nanocomposite HMO@NS exhibited substantially enhanced phosphate removal in the presence of sulfate, chloride, and nitrate at greater levels. This is mainly attributed to the pHpzc shift from 6.2 for the bulky HMO to 10.5 for the capsulated HMO nanoparticles, where HMO nanoparticles are positively charged at neutral pH. The ammonium groups of NS also favor phosphate adsorption through the Donnan effect. Cyclic column adsorption experiment indicated that the fresh HMO@NS could treat 460 bed volumes (BV) of a synthetic influent (from the initial concentration of 2 mg P[PO4(3-)]/L to 0.5 mg P[PO4(3-)]/L), while only 80 BV for NS. After the first time of regeneration by NaOH-NaCl solution, the capacity of HMO@NS was lowered to ∼ 300 BV and then kept constant for the subsequent 5 runs, implying the presence of both the reversible and irreversible adsorption sites of nano-HMO. Additional column adsorption feeding with a real bioeffluent further validated great potential of HMO@NS in advanced wastewater treatment. This study may provide an alternative approach to expand the usability of other metal oxides in water treatment.

  7. EXAFS Analyses of Innersphere Surface Complexations of Arsenate and Silicate on Natural Hydrous Ferric Oxides

    NASA Astrophysics Data System (ADS)

    Tommaseo, C. E.; Kersten, M.

    2002-12-01

    X-ray absorption spectroscopy (EXAFS) was used to determine the near range order of three elements (Fe, As, Si) on the surface of hydrous ferric oxide (HFO) from thermal water scales. Fe K-edge EXAFS analyses of the 2nd shell show a better fit including Si as backscattering neighbor. Validation of the Si-Fe bond was obtained by Si K-edge EXAFS spectra, where the light absorber element is surrounded favourably by much heavier second-shell elements. Least-squares fitting of the second-shell Fourier-filtered EXAFS spectrum in the k-range of 5-11 Å-1 yields in a Si-Fe distance of 3.10-3.13Å, and a Si-Si distance of 3.00Å. Both these interatomic distances and the coordination number N = 2 obtained for the Si-Fe shell are consistent with the formation of a corner-bridging bidentate binuclear (2C) surface complex on the HFO surface. The Si-Si bonds and existance of a vibrational band at 964 cm-1 in the infrared spectrum indicate polymerisation of the silicate on the HFO surface (Tommaseo and Kersten). As K-edge XANES analyses showed the As present in form of arsenate scavenged by the HFO phase. As and Si K-edge EXAFS analyses revealed both elements to compete for 2C surface complexation sites. A mean As-Fe distance of 3.03Å indicate an approx. equal distribution of arsenate between 2C (3.24Å) and another 1E (bidentate mononuclear surface complexation) sites (2.84Å). The average Fe-(O,OH) bond length of 2.09Å is compatible with a high proportion of distorted surficial FeIII(O,OH)6 octahedra in the colloidal HFO precipitates of the scale deposits. The slight distortion of the FeIII(O,OH)6 octahedra is consistent with the apparent strong binding of the 1E arsenate surface complexes (Manceau, 1995). The adverse effect of silicate would therefore be overpredicted without surface complexation models constructed to account for both surface functional groups. The Si K-edge EXAFS data provide also a basis for explaining at the molecular level the poisoning of HFO particle

  8. Surface complexation modeling of Cu(II) adsorption on mixtures of hydrous ferric oxide and kaolinite

    PubMed Central

    Lund, Tracy J; Koretsky, Carla M; Landry, Christopher J; Schaller, Melinda S; Das, Soumya

    2008-01-01

    Background The application of surface complexation models (SCMs) to natural sediments and soils is hindered by a lack of consistent models and data for large suites of metals and minerals of interest. Furthermore, the surface complexation approach has mostly been developed and tested for single solid systems. Few studies have extended the SCM approach to systems containing multiple solids. Results Cu adsorption was measured on pure hydrous ferric oxide (HFO), pure kaolinite (from two sources) and in systems containing mixtures of HFO and kaolinite over a wide range of pH, ionic strength, sorbate/sorbent ratios and, for the mixed solid systems, using a range of kaolinite/HFO ratios. Cu adsorption data measured for the HFO and kaolinite systems was used to derive diffuse layer surface complexation models (DLMs) describing Cu adsorption. Cu adsorption on HFO is reasonably well described using a 1-site or 2-site DLM. Adsorption of Cu on kaolinite could be described using a simple 1-site DLM with formation of a monodentate Cu complex on a variable charge surface site. However, for consistency with models derived for weaker sorbing cations, a 2-site DLM with a variable charge and a permanent charge site was also developed. Conclusion Component additivity predictions of speciation in mixed mineral systems based on DLM parameters derived for the pure mineral systems were in good agreement with measured data. Discrepancies between the model predictions and measured data were similar to those observed for the calibrated pure mineral systems. The results suggest that quantifying specific interactions between HFO and kaolinite in speciation models may not be necessary. However, before the component additivity approach can be applied to natural sediments and soils, the effects of aging must be further studied and methods must be developed to estimate reactive surface areas of solid constituents in natural samples. PMID:18783619

  9. Biogenic iron mineralization accompanying the dissimilatory reduction of hydrous ferric oxide by a groundwater bacterium

    NASA Astrophysics Data System (ADS)

    Fredrickson, James K.; Zachara, John M.; Kennedy, David W.; Dong, Hailang; Onstott, Tullis C.; Hinman, Nancy W.; Li, Shu-mei

    1998-10-01

    Dissimilatory iron-reducing bacteria (DIRB) couple the oxidation of organic matter or H 2 to the reduction of iron oxides. The factors controlling the rate and extent of these reduction reactions and the resulting solid phases are complex and poorly understood. Batch experiments were conducted with amorphous hydrous ferric oxide (HFO) and the DIRB Shewanella putrefaciens, strain CN32, in well-defined aqueous solutions to investigate the reduction of HFO and formation of biogenic Fe(II) minerals. Lactate-HFO solutions buffered with either bicarbonate or 1,4-piperazinediethanesulfonic acid (PIPES) containing various combinations of phosphate and anthraquinone-2,6-disulfonate (AQDS), were inoculated with S. putrefaciens CN32. AQDS, a humic acid analog that can be reduced to dihydroanthraquinone by CN32, was included because of its ability to function as an electron shuttle during microbial iron reduction and as an indicator of pe. Iron reduction was measured with time, and the resulting solids were analyzed by X-ray diffraction, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) with energy-dispersive X-ray spectroscopy (EDS) and selected area electron diffraction (SAED). In HCO 3- buffered medium with AQDS, HFO was rapidly and extensively reduced, and the resulting solids were dominated by ferrous carbonate (siderite). Ferrous phosphate (vivianite) was also present in HCO 3- medium containing P, and fine-grained magnetite was present as a minor phase in HCO 3- medium with or without P. In the PIPES-buffered medium, the rate and extent of reduction was strongly influenced by AQDS and P. With AQDS, HFO was rapidly converted to highly crystalline magnetite whereas in its absence, magnetite mineralization was slower and the final material less crystalline. In PIPES with both P and AQDS, a green rust type compound [Fe (6-x)IIFe xIII(OH) 12] x+[(A 2-) x/2 · yH 2O] x- was the dominant solid phase formed; in the absence of AQDS a poorly

  10. Economic Evaluation for the Production of Sorbents and Catalysts Derived from Hydrous Titanium Oxide Microspheres Prepared by the HMTA Internal Gelation Process

    SciTech Connect

    Collins, J.L.

    2001-01-11

    Hydrous metal oxides of Zr, Ti, Hf, Fe, Al, etc. are inorganic ion exchangers that have high selectivities and efficiencies for separating and removing fission products, actinides, and other undesirable elements from aqueous waste streams. In most cases, these ion exchangers are commercially available only as fine powders or as unstable granular particles that are not readily adaptable to continuous processing techniques such as column chromatography. Hydrous metal oxides can be prepared as microspheres by the internal gelation process. This process is unique in that it provides a means of making a usable engineered form of inorganic ion exchanger that can be used in large-scale column separations. With such material, the flow dynamics in column operations would be greatly enhanced. In addition, the microspheres are in a stable form that has little or no tendency to degrade under dynamic conditions. Another advantage of the process is that the gelation time and size of the microspheres can be controlled. Also, microspheres can be reproducibly prepared on either a small or a large scale-which is not always true for batch preparation of the powdered or granular forms. The use of these materials can be expanded in a number of ways. The process allows for the microspheres to be homogeneously embedded with fine particles of other selective ion exchangers, and for the microspheres (undried) to be chemically converted to microspheres of other ion-exchanger materials such as phosphates, silicophosphates, hexacyanoferrates, tungstates, and molybdates. This report presents an economic evaluation of the preparation of hydrous titanium oxide (HTiO) microspheres by an internal gelation process for use in making ion exchangers, catalysts, and getters. It also examines the estimated costs for a company to produce the material but does not discuss the price to be charged since that value would take into account company policy-matters that cannot be covered here. Since the volume

  11. Applications of x ray absorption fine structure to the in situ study of the effect of cobalt in nickel hydrous oxide electrodes for fuel cells and rechargeable batteries

    NASA Technical Reports Server (NTRS)

    Kim, Sunghyun; Tryk, Donald A.; Scherson, Daniel A.; Antonio, Mark R.

    1993-01-01

    Electronic and structural aspects of composite nickel-cobalt hydrous oxides have been examined in alkaline solutions using in situ X-ray absorption fine structure (XAFS). The results obtained have indicated that cobalt in this material is present as cobaltic ions regardless of the oxidation state of nickel in the lattice. Furthermore, careful analysis of the Co K-edge Extended X-ray absorption fine structure data reveals that the co-electrodeposition procedure generates a single phase, mixed metal hydrous oxide, in which cobaltic ions occupy nickel sites in the NiO2 sheet-like layers and not two intermixed phases each consisting of a single metal hydrous oxide.

  12. The ecological effect of acid conditions and precipitation of hydrous metal oxides in a Rocky Mountain stream

    USGS Publications Warehouse

    McKnight, Diane M.; Feder, G.L.

    1984-01-01

    Periphyton and benthic invertebrates assemblages were studied at the confluence of two Rocky Mountain streams, Deer Creek and the Snake River near Montezuma, Colorado. Upstream from the confluence the Snake River is acidic and enriched in dissolved trace metals, while Deer Creek is a typical Rocky Mountain stream. In the Snake River, downstream from the confluence, the pH increases and hydrous metal oxides precipitate and cover the streambed. The algal and benthic invertebrate communities in the upstream reaches of the Snake River and in Deer Creek were very different. A liverwort, Scapania undulata var. undulata, was abundant in the Snake River, and although periphyton were very sparse, there were as many benthic invertebrates as in Deer Creek. Downstream from the confleunce, the precipitation of hydrous metal oxides greatly decreased the abundance of periphyton and benthic invertebrates. This study shows that in streams metal precipitates covering the streambed may have a more deleterious effect on stream communities than high metal-ion activities. ?? 1984 Dr. W. Junk Publishers.

  13. Immobilization of strontium during iron biomineralization coupled to dissimilatory hydrous ferric oxide reduction

    NASA Astrophysics Data System (ADS)

    Roden, Eric E.; Leonardo, Michael R.; Ferris, F. Grant

    2002-09-01

    The potential for incorporation of strontium (Sr) into biogenic Fe(II)-bearing minerals formed during microbial reduction of synthetic hydrous ferric oxide (HFO) was investigated in circumneutral bicarbonate-buffered medium containing SrCl 2 at concentrations of 10 μM, 100 μM, or 1.0 mM. CaCl 2 (10 mM) was added to some experiments to simulate a Ca-rich groundwater. In Ca-free systems, 89 to 100% of total Sr was captured in solid-phase compounds formed during reduction of 30 to 40 mmol Fe(III) L -1 over a 1-month period. A smaller fraction of total Sr (25 to 34%) was incorporated into the solid phase in cultures amended with 10 mM CaCl 2. X-ray diffraction identified siderite and ferroan ankerite as major end products of HFO reduction in Ca-free and Ca-amended cultures, respectively. Scanning electron microscopy-energy dispersive x-ray spectroscopy revealed the presence of Sr associated with carbonate phases. Selective extraction of HFO reduction end products indicated that 46 to 100% of the solid-phase Sr was associated with carbonates. The sequestration of Sr into carbonate phases in the Ca-free systems occurred systematically according to a heterogeneous (Doerner-Hoskins) partition coefficient (D D-H) of 1.81 ± 0.15. This D D-H value was 2 to 10 times higher than values determined for incorporation of Sr (10 μM) into FeCO 3(s) precipitated abiotically at rates comparable to or greater than rates observed during HFO reduction, and fivefold higher than theoretical partition coefficients for equilibrium Fe(Sr)CO 3 solid solution formation. Surface complexation and entrapment of Sr by rapidly growing siderite crystals (and possibly other biogenic Fe(II) solids) provides an explanation for the intensive scavenging of Sr in the Ca-free systems. The results of abiotic siderite precipitation experiments in the presence and absence of excess Ca indicate that substitution of Ca for Sr at foreign element incorporation sites (mass action effect) on growing FeCO 3(s

  14. Immobilization of strontium during iron biomineralization coupled to dissimilatory hydrous ferric oxide reduction

    SciTech Connect

    Roden, Eric E.; Leonardo, Michael R.; Ferris, F. G.

    2002-08-15

    Abstract: The potential for incorporation of strontium (Sr) into biogenic Fe(II)-bearing minerals formed during microbial reduction of synthetic hydrous ferric oxide (HFO) was investigated in circumneutral bicarbonate-buffered medium containing SrCl2 at concentrations of 10 muM, 100 muM, or 1.0 mM. CaCl2 (10 mM) was added to some experiments to simulate a Ca-rich groundwater. In Ca-free systems, 89 to 100% of total Sr was captured in solid-phase compounds formed during reduction of 30 to 40 mmol Fe(III) L-1 over a 1-month period. A smaller fraction of total Sr (25 to 34%) was incorporated into the solid phase in cultures amended with 10 mM CaCl2. X-ray diffraction identified siderite and ferroan ankerite as major end products of HFO reduction in Ca-free and Ca-amended cultures, respectively. Scanning electron microscopy-energy dispersive x-ray spectroscopy revealed the presence of Sr associated with carbonate phases. Selective extraction of HFO reduction end products indicated that 46 to 100% of the solid-phase Sr was associated with carbonates. The sequestration of Sr into carbonate phases in the Ca-free systems occurred systematically according to a heterogeneous (Doerner-Hoskins) partition coefficient (DD-H) of 1.81+/-0.15. This DD-H value was 2 to 10 times higher than values determined for incorporation of Sr (10 muM) into FeCO3(S) precipitated abiotically at rates comparable to or greater than rates observed during HFO reduction, and fivefold higher than theoretical partition coefficients for equilibrium Fe(Sr)CO3 solid solution formation. Surface complexation and entrapment of Sr by rapidly growing siderite crystals (and possibly other biogenic Fe(II) solids) provides an explanation for the intensive scavenging of Sr in the Ca-free systems. The results of abiotic siderite precipitation experiments in the presence and absence of excess Ca indicate that substitution of Ca for Sr at foreign element incorporation sites (mass action effect) on growing FeCO3(S

  15. Removal of aluminum(III)-based turbidity in water using hydrous titanium oxide dispersed in ion-exchange resins

    SciTech Connect

    Venkataramani, B.; Karweer, S.B.; Iyer, R.K.; Phatak, G.M.; Iyer, R.M.

    1988-04-01

    An adsorber consisting of hydrous titanium oxide (HTiO) dispersed in a Dowex-type ion-exchange resin matrix (designated RT resins) has been developed which is capable of removing Al(III)-based colloidal dispersions in the neutral pH condition. The effect of resin crosslinking, particle size, HTiO loading, turbidity level, and flow rate on the turbidity removal efficiency of RT resins has been studied. It is demonstrated that a train of columns comprising RT resin, H/sup +/, and OH/sup -/ form of resins could be used for large-scale purification operations at high flow rates. These columns, apart from removing turbidity and associated radioactivity, can effectively remove dissolved uranium present in ppb levels when used for water purification in nuclear reactors.

  16. Synthesis of hydrous zirconium oxide-impregnated chitosan beads and their application for removal of fluoride and lead

    NASA Astrophysics Data System (ADS)

    Cho, Dong-Wan; Jeon, Byong-Hun; Jeong, Yoojin; Nam, In-Hyun; Choi, Ui-Kyu; Kumar, Rahul; Song, Hocheol

    2016-05-01

    A composite adsorbent capable of simultaneous removal of both cationic and anionic contaminants from aqueous solutions was developed by impregnating hydrous zirconium oxide (HZO) into chitosan beads (CB). The optimal mass ratio of chitosan to HZO was 2:2. The composite adsorbent (HZOCB) had the rugged surface (52.74 m2 g-1) with irregular cracks caused by HZO inclusion and amine functional groups. The rate of Pb2+ adsorption by HZOCB was relatively rapid. Most of Pb2+ (89%) was adsorbed within 2.5 h. A binary sorbate system was noticeably favorable for F- adsorption as compared to single sorbate system. Adsorption of F- and Pb2+ followed pseudo-second order kinetics. The maximum sorption capacities obtained from Langmuir isotherm model were 22.1 and 222.2 mg g-1, respectively. The study demonstrates that the developed composite could be a potential adsorbent for the simultaneous remediation of F- and Pb2+ contamination in water.

  17. Simultaneous microbial reduction of iron(III) and arsenic(V) in suspensions of hydrous ferric oxide.

    PubMed

    Campbell, Kate M; Malasarn, Davin; Saltikov, Chad W; Newman, Dianne K; Hering, Janet G

    2006-10-01

    Bacterial reduction of arsenic(V) and iron(III) oxides influences the redox cycling and partitioning of arsenic (As) between solid and aqueous phases in sediment-porewater systems. Two types of anaerobic bacterial incubations were designed to probe the relative order of As(V) and Fe(III) oxide reduction and to measure the effect of adsorbed As species on the rate of iron reduction, using hydrous ferric oxide (HFO) as the iron substrate. In one set of experiments, HFO was pre-equilibrated with As(V) and inoculated with fresh sediment from Haiwee Reservoir (Olancha, CA), an As-impacted field site. The second set of incubations consisted of HFO (without As) and As(III)- and As(V)- equilibrated HFO incubated with Shewanella sp. ANA-3 wild-type (WT) and ANA-3deltaarrA, a mutant unable to produce the respiratory As(V) reductase. Of the two pathways for microbial As(V) reduction (respiration and detoxification), the respiratory pathway was dominant under these experimental conditions. In addition, As(III) adsorbed onto the surface of HFO enhanced the rate of microbial Fe(III) reduction. In the sediment and ANA-3 incubations, As(V) was reduced simultaneously or prior to Fe(III), consistent with thermodynamic calculations based on the chemical conditions of the ANA-3 WT incubations.

  18. Arsenite adsorption on cryogels embedded with iron-aluminium double hydrous oxides: possible polishing step for smelting wastewater?

    PubMed

    Kumar, Prashanth Suresh; Onnby, Linda; Kirsebom, Harald

    2013-04-15

    Arsenic is among the most toxic elements and it commonly exists in water as arsenite (As(III)) and arsenate (As(V)) ions. As(III) removal often requires a pre-oxidation or pH adjustment step and it is a challenge to adsorb As(III) at circumneutral pH. In this study, iron-aluminium double hydrous oxides were synthesized and incorporated into cryogels. The resulting composite cryogels were evaluated for As(III) adsorption. Initial experiments indicated that the adsorbent showed similar adsorption kinetics for both As(V) and As(III) ions. The adsorption of As(III) best fit the Langmuir isotherm and the maximum adsorption capacity was 24.6 mg/g. Kinetic modeling indicated that the mechanism of adsorption was chemisorption, making the adsorbent-adsorbate interactions independent of charge and hence allowing the adsorbent to function equally efficient across pH 4-11. A Swedish smelting wastewater was used to evaluate the adsorption performance in continuous mode. The studies showed that the adsorbent was successful in reducing the arsenic concentrations below the European Union emission limit (0.15 mg/l) in a smelting wastewater collected after two precipitation processes. The arsenic removal was obtained without requiring a pH adjustment or a pre-oxidation step, making it a potential choice as an adsorbent for As(III) removal from industrial wastewaters.

  19. Hydrous manganese oxide doped gel probe sampler for measuring in situ reductive dissolution rates. 2. Field deployment.

    PubMed

    Farnsworth, Claire E; Griffis, Sarah D; Wildman, Richard A; Hering, Janet G

    2010-01-01

    In situ rates of reductive dissolution in submerged shoreline sediments at Lake Tegel (Berlin, Germany) were measured with a novel hydrous manganese (Mn) oxide-doped gel probe sampler in concert with equilibrium gel probe and sequential extraction measurements. Rates were low in the top 8 cm, then showed a peak from 8 to 14 cm, with a maximum at 12 cm depth. This rate corresponded with a peak in dissolved porewater iron (Fe) at 11 cm depth. Below 14 cm, the reductive dissolution rate reached an intermediate steady value. Lower rates at depth corresponded with increases in operationally defined fractions of carbonate-bound and organic- and sulfide-bound Mn and Fe as detected by sequential extraction. Observed rates of reductive dissolution, which reflect a capacity for Mn reduction rather than actual rates under ambient conditions, appear to correlate with porewater chemistry and sequential extraction fractions as expected in early sediment diagenesis, and are consistent with previous measurements of in situ reductive dissolution rates. Significant downward advection in this bank filtration setting depletes the Mn and Fe oxides in the sediments and enhances the transport of dissolved Fe and Mn into the infiltrating water.

  20. Mercury (II) reduction and co-precipitation of metallic mercury on hydrous ferric oxide in contaminated groundwater.

    PubMed

    Richard, Jan-Helge; Bischoff, Cornelia; Ahrens, Christian G M; Biester, Harald

    2016-01-01

    Mercury (Hg) speciation and sorption analyses in contaminated aquifers are useful for understanding transformation, retention, and mobility of Hg in groundwater. In most aquifers hydrous ferric oxides (HFOs) are among the most important sorbents for trace metals; however, their role in sorption or mobilization of Hg in aquifers has been rarely analyzed. In this study, we investigated Hg chemistry and Hg sorption to HFO under changing redox conditions in a highly HgCl2-contaminated aquifer (up to 870μgL(-1) Hg). Results from aqueous and solid phase Hg measurements were compared to modeled (PHREEQC) data. Speciation analyses of dissolved mercury indicated that Hg(II) forms were reduced to Hg(0) under anoxic conditions, and adsorbed to or co-precipitated with HFO. Solid phase Hg thermo-desorption measurements revealed that between 55 and 93% of Hg bound to HFO was elemental Hg (Hg(0)). Hg concentrations in precipitates reached more than 4 weight %, up to 7000 times higher than predicted by geochemical models that do not consider unspecific sorption to and co-precipitation of elemental Hg with HFO. The observed process of Hg(II) reduction and Hg(0) formation, and its retention and co-precipitation by HFO is thought to be crucial in HgCl2-contaminated aquifers with variable redox-conditions regarding the related decrease in Hg solubility (factor of ~10(6)), and retention of Hg in the aquifer.

  1. The Formation, Structure, and Ageing of As-Rich Hydrous Ferric Oxide at the Abandoned Sb Deposit Pezinok (Slovakia)

    SciTech Connect

    Majzlan,J.; Lalinska, B.; Chovan, M.; Jurkovic, L.; Milovska, S.; Gottlicher, J.

    2007-01-01

    The abandoned Sb deposit Pezinok in Slovakia is a significant source of As and Sb pollution that can be traced in the upper horizons of soils kilometers downstream. The source of the metalloids are two tailing impoundments which hold {approx}380,000 m{sup 3} of mining waste. The tailings and the discharged water have circumneutral pH values (7.0 {+-} 0.6) because the acidity generated by the decomposition of the primary sulfides (pyrite, FeS{sub 2}; arsenopyrite, FeAsS; berthierite, FeSb{sub 2}S{sub 4}) is rapidly neutralized by the abundant carbonates. The weathering rims on the primary sulfides are iron oxides which act as very efficient scavengers of As and Sb (with up to 19.2 wt% As and 23.7 wt% Sb). In-situ {mu}-XANES experiments indicate that As in the weathering rims is fully oxidized (As{sup 5+}). The pore solutions in the impoundment body contain up to 81 ppm As and 2.5 ppm Sb. Once these solutions are discharged from the impoundments, they precipitate or deposit masses of As-rich hydrous ferric oxide (As-HFO) with up to 28.3 wt% As{sub 2}O{sub 5} and 2.7 wt% Sb. All As-HFO samples are amorphous to X-rays. They contain Fe and As in their highest oxidation state and in octahedral and tetrahedral coordination, respectively, as suggested by XANES and EXAFS studies on Fe K and As K edges. The iron octahedra in the As-HFO share edges to form short single chains and the chains polymerize by sharing edges or corners with the adjacent units. The arsenate ions attach to the chains in a bidentate-binuclear and monodentate fashion. In addition, hydrogen-bonded complexes may exist to satisfy the bonding requirements of all oxygen atoms in the first coordination sphere of As{sup 5+}. Structural changes in the As-HFO samples were traced by chemical analyses and Fe EXAFS spectroscopy during an ageing experiment. As the samples age, As becomes more easily leachable. EXAFS spectra show a discernible trend of increasing number of Fe-Fe pairs at a distance of 3

  2. Kinetic Modeling of Phosphate Adsorption by Preformed and In situ formed Hydrous Ferric Oxides at Circumneutral pH

    PubMed Central

    Mao, Yanpeng; Yue, Qinyan

    2016-01-01

    Kinetics of phosphate removal by Fe(III) was investigated by both preformed and in situ formed hydrous ferric oxides (HFO) at pH 6.0–8.0. A pseudo-second-order empirical model was found to adequately describe phosphate removal in the two cases. The Elovich and intra-particle diffusion models, however, were only capable of describing phosphate adsorption to preformed HFO (PF-HFO). By using surface complexation kinetic models (SCKMs) to describe phosphate adsorption to PF-HFO, the adsorption rate constant (0.0386–0.205 mM−1 min−1 for SCKM-1 and 0.0680–0.274 mM−1 min−1 for SCKM-2) decreased with increasing pH while the protonation reaction rate constant in SCKM-2 (0.0776–0.0947 mM−1 min−1) increased over the pH range 6.0–8.0. Using the rate constants obtained from the process of phosphate adsorption to PF-HFO, the amount of active surface sites on the in situ formed HFO were calculated as 0.955 ± 0.170, 1.46 ± 0.39 and 2.98 ± 0.78 mM for pH = 6.0, 7.0 and 8, respectively. Generally, as the SCKMs incorporate phosphate complexation on HFO surface sites and protons competiting for the surface sites, they could provide a good description of the rate and extent of phosphate removal by both preformed and in-situ formed HFO over a wide range of conditions. PMID:27739456

  3. Kinetic Modeling of Phosphate Adsorption by Preformed and In situ formed Hydrous Ferric Oxides at Circumneutral pH

    NASA Astrophysics Data System (ADS)

    Mao, Yanpeng; Yue, Qinyan

    2016-10-01

    Kinetics of phosphate removal by Fe(III) was investigated by both preformed and in situ formed hydrous ferric oxides (HFO) at pH 6.0–8.0. A pseudo-second-order empirical model was found to adequately describe phosphate removal in the two cases. The Elovich and intra-particle diffusion models, however, were only capable of describing phosphate adsorption to preformed HFO (PF-HFO). By using surface complexation kinetic models (SCKMs) to describe phosphate adsorption to PF-HFO, the adsorption rate constant (0.0386–0.205 mM‑1 min‑1 for SCKM-1 and 0.0680–0.274 mM‑1 min‑1 for SCKM-2) decreased with increasing pH while the protonation reaction rate constant in SCKM-2 (0.0776–0.0947 mM‑1 min‑1) increased over the pH range 6.0–8.0. Using the rate constants obtained from the process of phosphate adsorption to PF-HFO, the amount of active surface sites on the in situ formed HFO were calculated as 0.955 ± 0.170, 1.46 ± 0.39 and 2.98 ± 0.78 mM for pH = 6.0, 7.0 and 8, respectively. Generally, as the SCKMs incorporate phosphate complexation on HFO surface sites and protons competiting for the surface sites, they could provide a good description of the rate and extent of phosphate removal by both preformed and in-situ formed HFO over a wide range of conditions.

  4. Rapid and efficient removal of fluoride ions from aqueous solution using a polypyrrole coated hydrous tin oxide nanocomposite.

    PubMed

    Parashar, Kamya; Ballav, Niladri; Debnath, Sushanta; Pillay, Kriveshini; Maity, Arjun

    2016-08-15

    Polypyrrole/hydrous tin oxide nanocomposites (PPy/HSnO NC 1, 2, 3, 4 and 5) were synthesized through encapsulating HSnO by the PPy via an in situ polymerization for fluoride removal. The optimized adsorbent i.e. PPy/HSnO NC 3 was characterized using FE-SEM, HR-TEM, ATR-FTIR, XRD, BET, TGA and zeta sizer. Microscopic images revealed the encapsulation of HSnO by precipitating PPy during polymerization. The FTIR and XRD studies confirmed the presence of both constituents. The BET surface area and pHpzc of the adsorbent were estimated to be 65.758m(2)/g and 7.6, respectively. The fluoride adsorption followed pseudo-second-order model and was commendably rapid. The monolayer adsorption capacity was found to be 26.16-28.99mg/g at pH 6.5±0.1. The thermodynamic parameters indicated the sorption of F(-) was spontaneous, endothermic and that physisorption occurred. The calculated activation energy (Ea∼20.05kJ/mol) provided further evidence of a physisorption mechanism. Moreover, the adsorbent performed very well over a considerably wide pH range of 3.5-8.5 and in the presence of other co-existing ions. The regeneration of the F(-) laden PPy/HSnO NC 3 showed a high desorption efficiency of 95.81% up to 3 cycles. Ground water tested results also demonstrate the potential utility of the PPy/HSnO NC as an effective adsorbent. PMID:27209396

  5. Crystallization of oxidized, moderately hydrous arc basalt at mid- to lower-crustal pressures: Implications for andesite genesis

    USGS Publications Warehouse

    Blatter, Dawnika L.; Sisson, Thomas W.; Hankins, W. Ben

    2013-01-01

    This study focuses on the production of convergent margin calc-alkaline andesites by crystallization–differentiation of basaltic magmas in the lower to middle crust. Previous experimental studies show that dry, reduced, subalkaline basalts differentiate to tholeiitic (high Fe/Mg) daughter liquids, but the influences of H2O and oxidation on differentiation are less well established. Accordingly, we performed crystallization experiments at controlled oxidized fO2 (Re–ReO2 ≈ ΔNi–NiO + 2) on a relatively magnesian basalt (8.7 wt% MgO) typical of mafic magmas erupted in the Cascades near Mount Rainier, Washington. The basalt was synthesized with 2 wt% H2O and run at 900, 700, and 400 MPa and 1,200 to 950 °C. A broadly clinopyroxenitic crystallization interval dominates near the liquidus at 900 and 700 MPa, consisting of augite + olivine + orthopyroxene + Cr-spinel (in decreasing abundance). With decreasing temperature, plagioclase crystallizes, Fe–Ti-oxide replaces spinel, olivine dissolves, and finally amphibole appears, producing gabbroic and then amphibole gabbroic crystallization stages. Enhanced plagioclase stability at lower pressure narrows the clinopyroxenitic interval and brings the gabbroic interval toward the liquidus. Liquids at 900 MPa track along Miyashiro’s (Am J Sci 274(4):321–355, 1974) tholeiitic versus calc-alkaline boundary, whereas those at 700 and 400 MPa become calc-alkaline at silica contents ≥56 wt%. This difference is chiefly due to higher temperature appearance of magnetite (versus spinel) at lower pressures. Although the evolved liquids are similar in many respects to common calc-alkaline andesites, the 900 and 700 MPa liquids differ in having low CaO concentrations due to early and abundant crystallization of augite, with the result that those liquids become peraluminous (ASI: molar Al/(Na + K + 2Ca) > 1) at ≥61 wt% SiO2, similar to liquids reported in other studies of the high-pressure crystallization of hydrous basalts

  6. An easy way to prepare monolithic inorganic oxide aerogels.

    PubMed

    Ren, Lili; Cui, Sumin; Cao, Fengchao; Guo, Qinghui

    2014-09-15

    Inorganic oxide aerogels have unique thermal, optical, electrical, magnetic, and chemical properties, which result in them potentially having a broad range of applications. However, their preparation is commonly based on a supercritical drying method, which greatly limits real applications of aerogels and their commercialization. Here we demonstrate a general method for drying wet gels to form aerogels that is based on the sublimation of organic solvent. The organic solvent must have a low surface tension, undergo sublimation easily, and have a high freezing point to allow the rapid synthesis of monolithic inorganic oxide aerogels under vacuum conditions. This cost-effective process will facilitate application of aerogel materials. This approach may also be used for the preparation of other porous materials, whose theoretical and practical applications should be investigated.

  7. Hydrous ferric oxide precipitation in the presence of nonmetabolizing bacteria: Constraints on the mechanism of a biotic effect

    NASA Astrophysics Data System (ADS)

    Rancourt, Denis G.; Thibault, Pierre-Jean; Mavrocordatos, Denis; Lamarche, Gilles

    2005-02-01

    We have used room temperature and cryogenic 57Fe Mössbauer spectroscopy, powder X-ray diffraction (pXRD), mineral magnetometry, and transmission electron microscopy (TEM), to study the synthetic precipitation of hydrous ferric oxides (HFOs) prepared either in the absence (abiotic, a-HFO) or presence (biotic, b-HFO) of nonmetabolizing bacterial cells ( Bacillus subtilis or Bacillus licheniformis, ˜10 8 cells/mL) and under otherwise identical chemical conditions, starting from Fe(II) (10 -2, 10 -3, or 10 -4 mol/L) under open oxic conditions and at different pH (6-9). We have also performed the first Mössbauer spectroscopy measurements of bacterial cell wall ( Bacillus subtilis) surface complexed Fe, where Fe(III) (10 -3.5-10 -4.5 mol/L) was added to a fixed concentration of cells (˜10 8 cells/mL) under open oxic conditions and at various pH (2.5-4.3). We find that non-metabolic bacterial cell wall surface complexation of Fe is not passive in that it affects Fe speciation in at least two ways: (1) it can reduce Fe(III) to sorbed-Fe 2+ by a proposed steric and charge transfer effect and (2) it stabilizes Fe(II) as sorbed-Fe 2+ against ambient oxidation. The cell wall sorption of Fe occurs in a manner that is not compatible with incorporation into the HFO structure (different coordination environment and stabilization of the ferrous state) and the cell wall-sorbed Fe is not chemically bonded to the HFO particle when they coexist (the sorbed Fe is not magnetically polarized by the HFO particle in its magnetically ordered state). This invalidates the concept that sorption is the first step in a heterogeneous nucleation of HFO onto bacterial cell walls. Both the a-HFOs and the b-HFOs are predominantly varieties of ferrihydrite (Fh), often containing admixtures of nanophase lepidocrocite (nLp), yet they show significant abiotic/biotic differences: Biotic Fh has less intraparticle (including surface region) atomic order (Mössbauer quadrupole splitting), smaller primary

  8. Assessment of the Morphological, Biochemical, and Kinetic Properties for Candida rugosa Lipase Immobilized on Hydrous Niobium Oxide to Be Used in the Biodiesel Synthesis

    PubMed Central

    Miranda, Michele; Urioste, Daniele; Andrade Souza, Livia T.; Mendes, Adriano A.; de Castro, Heizir F.

    2011-01-01

    Lipase from Candida rugosa (CRL) was immobilized by covalent attachment on hydrous niobium oxide. The matrix could effectively be attached to the enzyme with high retention of activity and prevent its leakage. Following immobilization, CRL exhibited improved storage stability and performed better at higher incubation temperatures. In addition, the enzyme retained most of its catalytic efficiency after successive operational cycles. The immobilized derivative was also fully characterized with respect to its morphological properties: particle size, surface specific area, and pore size distribution. Structural integrity and conformational changes, such as surface cavities in the support, set by the lipase procedure, were observed by Scanning Electron Microscopy. Additionally, a comparative study between free and immobilized lipases was provided in terms of pH, temperature, and thermal stability. CRL derivative was evaluated for the synthesis of biodiesel employing babassu oil and short chain alcohols. The process was feasible only for oil and butanol reaction system. PMID:21876790

  9. Sorption of dissolved organic carbon by hydrous aluminum and iron oxides occurring at the confluence of deer creek with the Snake River, Summit County, Colorado

    USGS Publications Warehouse

    McKnight, Diane M.; Bencala, K.E.; Zellweger, G.W.; Aiken, G.R.; Feder, G.L.; Thorn, K.A.

    1992-01-01

    Organic solute sorption by hydrous iron and aluminum oxides was studied in an acidic, metal-enriched stream (the Snake River) at its confluence with a pristine stream (Deer Creek). From 1979 to 1986, typically 40% of the dissolved organic carbon (DOC) was removed from solution by sorption onto aluminum and iron oxides, which precipitate as the two streamwaters mix. Upstream DOC concentrations, which increase during snowmelt, were identified as the most significant variables in a multiple regression for determining the DOC concentration below the confluence, and the extent of Al and Fe precipitation was much less significant. On hourly timescales, removal of Al and Fe varied erratically but DOC removal was steady, indicating that "sorbable" organic solutes are sorbed either by precipitating oxides or by oxides on the streambed. Characterization of two reactive DOC fractions (fulvic and hydrophilic acids) showed that sorption results in chemical fractionation. Molecules with greater contents of aromatic moieties, carboxylic acid groups, and amino acid residues were preferentially sorbed, which is consistent with the ligand exchange-surface complexation model.

  10. OXIDATIVE COUPLING OF METHANE USING INORGANIC MEMBRANE REACTORS

    SciTech Connect

    Dr. Y.H. Ma; Dr. W.R. Moser; Dr. A.G. Dixon; Dr. A.M. Ramachandra; Dr. Y. Lu; C. Binkerd

    1998-04-01

    The objective of this research is to study the oxidative coupling of methane in catalytic inorganic membrane reactors. A specific target is to achieve conversion of methane to C{sub 2} hydrocarbons at very high selectivity and higher yields than in conventional non-porous, co-feed, fixed bed reactors by controlling the oxygen supply through the membrane. A membrane reactor has the advantage of precisely controlling the rate of delivery of oxygen to the catalyst. This facility permits balancing the rate of oxidation and reduction of the catalyst. In addition, membrane reactors minimize the concentration of gas phase oxygen thus reducing non selective gas phase reactions, which are believed to be a main route for the formation of CO{sub x} products. Such gas phase reactions are a cause of decreased selectivity in the oxidative coupling of methane in conventional flow reactors. Membrane reactors could also produce higher product yields by providing better distribution of the reactant gases over the catalyst than the conventional plug flow reactors. Membrane reactor technology also offers the potential for modifying the membranes both to improve catalytic properties as well as to regulate the rate of the permeation/diffusion of reactants through the membrane to minimize by-product generation. Other benefits also exist with membrane reactors, such as the mitigation of thermal hot-spots for highly exothermic reactions such as the oxidative coupling of methane. The application of catalytically active inorganic membranes has potential for drastically increasing the yield of reactions which are currently limited by either thermodynamic equilibria, product inhibition, or kinetic selectivity.

  11. Role of hydrous iron oxide formation in attenuation and diel cycling of dissolved trace metals in a stream affected by acid rock drainage

    USGS Publications Warehouse

    Parker, S.R.; Gammons, C.H.; Jones, C.A.; Nimick, D.A.

    2007-01-01

    Mining-impacted streams have been shown to undergo diel (24-h) fluctuations in concentrations of major and trace elements. Fisher Creek in south-central Montana, USA receives acid rock drainage (ARD) from natural and mining-related sources. A previous diel field study found substantial changes in dissolved metal concentrations at three sites with differing pH regimes during a 24-h period in August 2002. The current work discusses follow-up field sampling of Fisher Creek as well as field and laboratory experiments that examine in greater detail the underlying processes involved in the observed diel concentration changes. The field experiments employed in-stream chambers that were either transparent or opaque to light, filled with stream water and sediment (cobbles coated with hydrous Fe and Al oxides), and placed in the stream to maintain the same temperature. Three sets of laboratory experiments were performed: (1) equilibration of a Cu(II) and Zn(II) containing solution with Fisher Creek stream sediment at pH 6.9 and different temperatures; (2) titration of Fisher Creek water from pH 3.1 to 7 under four different isothermal conditions; and (3) analysis of the effects of temperature on the interaction of an Fe(II) containing solution with Fisher Creek stream sediment under non-oxidizing conditions. Results of these studies are consistent with a model in which Cu, Fe(II), and to a lesser extent Zn, are adsorbed or co-precipitated with hydrous Fe and Al oxides as the pH of Fisher Creek increases from 5.3 to 7.0. The extent of metal attenuation is strongly temperature-dependent, being more pronounced in warm vs. cold water. Furthermore, the sorption/co-precipitation process is shown to be irreversible; once the Cu, Zn, and Fe(II) are removed from solution in warm water, a decrease in temperature does not release the metals back to the water column. ?? 2006 Springer Science+Business Media B.V.

  12. Oxidative coupling of methane using inorganic membrane reactor

    SciTech Connect

    Ma, Y.H.; Moser, W.R.; Dixon, A.G.

    1995-12-31

    The goal of this research is to improve the oxidative coupling of methane in a catalytic inorganic membrane reactor. A specific target is to achieve conversion of methane to C{sub 2} hydrocarbons at very high selectivity and relatively higher yields than in fixed bed reactors by controlling the oxygen supply through the membrane. A membrane reactor has the advantage of precisely controlling the rate of delivery of oxygen to the catalyst. This facility permits balancing the rate of oxidation and reduction of the catalyst. In addition, membrane reactors minimize the concentration of gas phase oxygen thus reducing non selective gas phase reactions, which are believed to be a main route for formation of CO{sub x} products. Such gas phase reactions are a cause for decreased selectivity in oxidative coupling of methane in conventional flow reactors. Membrane reactors could also produce higher product yields by providing better distribution of the reactant gases over the catalyst than the conventional plug flow reactors. Modeling work which aimed at predicting the observed experimental trends in porous membrane reactors was also undertaken in this research program.

  13. Dietary uptake of Cu sorbed to hydrous iron oxide is linked to cellular toxicity and feeding inhibition in a benthic grazer

    USGS Publications Warehouse

    Cain, Daniel J.; Croteau, Marie-Noele; Fuller, Christopher C.; Ringwood, Amy H.

    2016-01-01

    Whereas feeding inhibition caused by exposure to contaminants has been extensively documented, the underlying mechanism(s) are less well understood. For this study, the behavior of several key feeding processes, including ingestion rate and assimilation efficiency, that affect the dietary uptake of Cu were evaluated in the benthic grazer Lymnaea stagnalis following 4–5 h exposures to Cu adsorbed to synthetic hydrous ferric oxide (Cu–HFO). The particles were mixed with a cultured alga to create algal mats with Cu exposures spanning nearly 3 orders of magnitude at variable or constant Fe concentrations, thereby allowing first order and interactive effects of Cu and Fe to be evaluated. Results showed that Cu influx rates and ingestion rates decreased as Cu exposures of the algal mat mixture exceeded 104 nmol/g. Ingestion rate appeared to exert primary control on the Cu influx rate. Lysosomal destabilization rates increased directly with Cu influx rates. At the highest Cu exposure where the incidence of lysosomal membrane damage was greatest (51%), the ingestion rate was suppressed 80%. The findings suggested that feeding inhibition was a stress response emanating from excessive uptake of dietary Cu and cellular toxicity.

  14. Absorption of inorganic halides produced from Freon 12 by calcium carbonate containing iron(III) oxide

    SciTech Connect

    Imamura, Seiichiro; Matsuba, Yoichi; Yamada, Etsu; Takai, Kenji; Utani, Kazunori

    1997-09-01

    Inorganic halides produced by the catalytic decomposition of Freon 12 were fixed by calcium carbonate, which is the main component of limestone. Iron(III) oxide, which is present as a contaminant in limestone, promoted the absorption of the halides by calcium carbonate at low temperatures. The supposed action of iron(III) oxide was to first react with inorganic halides, forming iron halides, and, then, transfer them to calcium carbonate to replace carbonate ion in a catalytic way. Thus, calcium carbonate containing iron oxides (limestone) can be used as an effective absorbent for the inorganic halogens produced during the decomposition of Freons.

  15. [Removal and Recycle of Phosphor from Water Using Magnetic Core/Shell Structured Fe₃O₄ @ SiO₂Nanoparticles Functionalized with Hydrous Aluminum Oxide].

    PubMed

    Lai, Li; Xie, Qiang; Fang, Wen-kan; Xing, Ming-chao; Wu, De-yi

    2016-04-15

    A novel magnetic core/shell structured nano-particle Fe₃O₄@ SiO₂phosphor-removal ahsorbent functionalized with hydrous aluminum oxides (Fe₃O₄@ SiO₂@ Al₂O₃· nH₂O) was synthesized. Fe₃O₄@ SiO₂@ Al₂O₃· nH₂O was characterized by XRD, TEM, VSM and BET nitrogen adsorption experiment. The XRD and TEM results demonstrated the presence of the core/shell structure, with saturated magnetization and specific surface area of 56.00 emu · g⁻¹ and 47.27 m² · g⁻¹, respectively. In batch phosphor adsorption experiment, the Langmuir adsorption maximum capacity was 12.90 mg · g⁻¹ and nearly 96% phosphor could be rapidly removed within a contact time of 40 mm. Adsorption of phosphor on Fe₃O₄@ SiO₂@ Al₂O₃ · nH₂O was highly dependent on pH condition, and the favored pH range was 5-9 in which the phosphor removal rate was above 90%. In the treatment of sewage water, the recommended dosage was 1.25 kg · t⁻¹. In 5 cycles of adsorption-regeneration-desorption experiment, over 90% of the adsorbed phosphor could be desorbed with 1 mol · L⁻¹ NaOH, and Fe₃O₄@ SiO₂@ Al₂O₃· nH₂O could be reused after regeneration by pH adjustment with slightly decreased phosphor removal rate with increasing recycling number, which proved the recyclability of Fe₃O₄@ SiO₂@ Al₂O₃· nH₂O and thereby its potential in recycling of phosphor resources. PMID:27548967

  16. [Removal and Recycle of Phosphor from Water Using Magnetic Core/Shell Structured Fe₃O₄ @ SiO₂Nanoparticles Functionalized with Hydrous Aluminum Oxide].

    PubMed

    Lai, Li; Xie, Qiang; Fang, Wen-kan; Xing, Ming-chao; Wu, De-yi

    2016-04-15

    A novel magnetic core/shell structured nano-particle Fe₃O₄@ SiO₂phosphor-removal ahsorbent functionalized with hydrous aluminum oxides (Fe₃O₄@ SiO₂@ Al₂O₃· nH₂O) was synthesized. Fe₃O₄@ SiO₂@ Al₂O₃· nH₂O was characterized by XRD, TEM, VSM and BET nitrogen adsorption experiment. The XRD and TEM results demonstrated the presence of the core/shell structure, with saturated magnetization and specific surface area of 56.00 emu · g⁻¹ and 47.27 m² · g⁻¹, respectively. In batch phosphor adsorption experiment, the Langmuir adsorption maximum capacity was 12.90 mg · g⁻¹ and nearly 96% phosphor could be rapidly removed within a contact time of 40 mm. Adsorption of phosphor on Fe₃O₄@ SiO₂@ Al₂O₃ · nH₂O was highly dependent on pH condition, and the favored pH range was 5-9 in which the phosphor removal rate was above 90%. In the treatment of sewage water, the recommended dosage was 1.25 kg · t⁻¹. In 5 cycles of adsorption-regeneration-desorption experiment, over 90% of the adsorbed phosphor could be desorbed with 1 mol · L⁻¹ NaOH, and Fe₃O₄@ SiO₂@ Al₂O₃· nH₂O could be reused after regeneration by pH adjustment with slightly decreased phosphor removal rate with increasing recycling number, which proved the recyclability of Fe₃O₄@ SiO₂@ Al₂O₃· nH₂O and thereby its potential in recycling of phosphor resources.

  17. Filamentous hydrous ferric oxide biosignatures in a pipeline carrying acid mine drainage at Iron Mountain Mine, California

    USGS Publications Warehouse

    Williams, Amy J.; Alpers, Charles N.; Sumner, Dawn Y.; Campbell, Kate M.

    2016-01-01

    A pipeline carrying acidic mine effluent at Iron Mountain, CA, developed Fe(III)-rich precipitate caused by oxidation of Fe(II)aq. The native microbial community in the pipe included filamentous microbes. The pipe scale consisted of microbial filaments, and schwertmannite (ferric oxyhydroxysulfate, FOHS) mineral spheres and filaments. FOHS filaments contained central lumina with diameters similar to those of microbial filaments. FOHS filament geometry, the geochemical environment, and the presence of filamentous microbes suggest that FOHS filaments are mineralized microbial filaments. This formation of textural biosignatures provides the basis for a conceptual model for the development and preservation of biosignatures in other environments.

  18. Development of Surface Complexation Models of Cr(VI) Adsorption on Soils, Sediments and Model Mixtures of Kaolinite, Montmorillonite, γ-Alumina, Hydrous Manganese and Ferric Oxides and Goethite

    SciTech Connect

    Koretsky, Carla

    2013-11-29

    Hexavalent chromium is a highly toxic contaminant that has been introduced into aquifers and shallow sediments and soils via many anthropogenic activities. Hexavalent chromium contamination is a problem or potential problem in the shallow subsurface at several DOE sites, including Hanford, Idaho National Laboratory, Los Alamos National Laboratory and the Oak Ridge Reservation (DOE, 2008). To accurately quantify the fate and transport of hexavalent chromium at DOE and other contaminated sites, robust geochemical models, capable of correctly predicting changes in chromium chemical form resulting from chemical reactions occurring in subsurface environments are needed. One important chemical reaction that may greatly impact the bioavailability and mobility of hexavalent chromium in the subsurface is chemical binding to the surfaces of particulates, termed adsorption or surface complexation. Quantitative thermodynamic surface complexation models have been derived that can correctly calculate hexavalent chromium adsorption on well-characterized materials over ranges in subsurface conditions, such pH and salinity. However, models have not yet been developed for hexavalent chromium adsorption on many important constituents of natural soils and sediments, such as clay minerals. Furthermore, most of the existing thermodynamic models have been developed for relatively simple, single solid systems and have rarely been tested for the complex mixtures of solids present in real sediments and soils. In this study, the adsorption of hexavalent chromium was measured as a function of pH (3-10), salinity (0.001 to 0.1 M NaNO3), and partial pressure of carbon dioxide(0-5%) on a suite of naturally-occurring solids including goethite (FeOOH), hydrous manganese oxide (MnOOH), hydrous ferric oxide (Fe(OH)3), γ-alumina (Al2O3), kaolinite (Al2Si2O5(OH)4), and montmorillonite (Na3(Al, Mg)2Si4O10(OH)2-nH2O). The results show that all of these materials can bind substantial quantities of

  19. Sb(III) and Sb(V) Sorption onto Al-Rich Phases: Hydrous Al Oxide and the Clay Minerals Kaolinite KGa-1b and Oxidized and Reduced Nontronite NAu-1

    SciTech Connect

    Ilgen, Anastasia G.; Trainor, Thomas P.

    2012-11-13

    We have studied the immobilization of Sb(III) and Sb(V) by Al-rich phases - hydrous Al oxide (HAO), kaolinite (KGa-1b), and oxidized and reduced nontronite (NAu-1) - using batch experiments to determine the uptake capacity and the kinetics of adsorption and Extended X-ray Absorption Fine Structure (EXAFS) Spectroscopy to characterize the molecular environment of adsorbed Sb. Both Sb(III) and Sb(V) are adsorbed in an inner-sphere mode on the surfaces of the studied substrates. The observed adsorption geometry is mostly bidentate corner-sharing, with some monodentate complexes. The kinetics of adsorption is relatively slow (on the order of days), and equilibrium adsorption isotherms are best fit using the Freundlich model. The oxidation state of the structural Fe within nontronite affects the adsorption capacity: if the clay is reduced, the adsorption capacity of Sb(III) is slightly decreased, while Sb(V) uptake is increased significantly. This may be a result of the presence of dissolved Fe(II) in the reduced nontronite suspensions or associated with the structural rearrangements in nontronite due to reduction. These research findings indicate that Sb can be effectively immobilized by Al-rich phases. The increase in Sb(V) uptake in response to reducing structural Fe in clay can be important in natural settings since Fe-rich clays commonly go through oxidation-reduction cycles in response to changing redox conditions.

  20. Cu-ZSM-5: A biomimetic inorganic model for methane oxidation

    PubMed Central

    Vanelderen, Pieter; Hadt, Ryan G.; Smeets, Pieter J.; Solomon, Edward I.; Schoonheydt, Robert A.; Sels, Bert F.

    2012-01-01

    The present work highlights recent advances in elucidating the methane oxidation mechanism of inorganic Cu-ZSM-5 biomimic and in identifying the reactive intermediates that are involved. Such molecular understanding is important in view of upgrading abundantly available methane, but also to comprehend the working mechanism of genuine Cu-containing oxidation enzymes. PMID:23487537

  1. Inorganic metal oxide/organic polymer nanocomposites and method thereof

    DOEpatents

    Gash, Alexander E.; Satcher, Joe H.; Simpson, Randy

    2004-03-30

    A synthetic method for preparation of hybrid inorganic/organic energetic nanocomposites is disclosed herein. The method employs the use of stable metal inorganic salts and organic solvents as well as an organic polymer with good solubility in the solvent system to produce novel nanocomposite energetic materials. In addition, fuel metal powders (particularly those that are oxophillic) can be incorporated into composition. This material has been characterized by thermal methods, energy-filtered transmission electron microscopy (EFTEM), N.sub.2 adsoprtion/desorption methods, and Fourier-Transform (FT-IR) spectroscopy. According to these characterization methods the organic polymer phase fills the nanopores of the composite material, providing superb mixing of the component phases in the energetic nanocomposite.

  2. Oxidation control of fluxes for mixed-valent inorganic oxide materials synthesis

    NASA Astrophysics Data System (ADS)

    Schrier, Marc David

    This dissertation is concerned with controlling the flux synthesis and ensuing physical properties of mixed-valence metal oxides. Molten alkali metal nitrates and hydroxides have been explored to determine and exploit their variable redox chemistries for the synthesis of mixed-valent oxide materials. Cationic and anionic additives have been utilized in these molten salts to control the relative concentrations of the redox-active species present to effectively tune and cap the electrochemical potential of the flux. Atoms like bismuth, copper, and manganese are capable of providing different numbers of electrons for bonding. With appropriate doping near the metal-insulator transition, many of these mixed-valent inorganic metal oxides exhibit extraordinary electronic and magnetic properties. Traditionally, these materials have been prepared by classical high temperature solid state routes where microscopic homogeneity is hard to attain. In these routes, the starting composition dictates the doping level, and in turn, the formal oxidation state achieved. Molten flux syntheses developed in this work have provided the potential for preparing single-phase, homogeneous, and crystalline materials. The redox-active fluxes provide a medium for enhanced doping and mixed-valency control in which the electrochemical potential adjusts the formal oxidation state, and the doping takes place to maintain charge neutrality. The two superconductor systems investigated are: (1) the potassium-doped barium bismuth oxides, and (2) the alkali metal- and alkaline earth metal-doped lanthanum copper oxides. Controlled oxidative doping has been achieved in both systems by two different approaches. The superconducting properties of these materials have been assessed, and the materials have been characterized by powder X-ray diffraction and e-beam microprobe elemental analyses. In the course of these studies, several other materials have been identified. Analysis of these materials, and the

  3. Megafans as Hydrous Environments

    NASA Technical Reports Server (NTRS)

    Wilkinson, M. Justin; Miller, R. McG.; Allen, C. C.; Kreslavsky, M. H.; Eckardt, F.

    2009-01-01

    The mesoscale sedimentary environment known as the megafan, is a low-angle, partial cone of fluvial sediment generated where a river enters an unconfined basin where it begins the process of avulsing over wide areas. In shifting to different positions, the river lays down a partial cone of sediment and establishes a characteristic radial pattern of paleo courses. The apparent paucity of sedimentary bodies obviously tied to martian outflow channels may also relate to the difficulty of recognition due to their sheer size and featurelessness. However, the existence of megafans on Mars is being examined now that their ubiquity and characteristics on Earth are better understood. Accordingly we suggest two likely candidates on Mars: Maja Valles fluvial cone and Amazonis Planitia fluvial sedimentary bodies. Two cryptic examples from Amazonis Planitia may be important for understanding subsurface hydrous accumulation. For at least some of its history, discharges from Mangala Valles likely resulted in megafans. Distances from the end of Mangala Valles to the northern (low) margin of the planitia are very large, a fact that has suggested that fluvial emplacement was unlikely. However, the megafan model shows that long megafan radii are indeed feasible. It has been suggested further that discharge from Labou Vallis (8.5S 154.5W) must have led to fluvial sedimentation in the planitia. We suggest that during locally non-lacustrine/ocean phases, this sedimentation would have occurred in the form of megafans. However, the megafan model shows that long megafan radii are indeed feasible. It has been suggested further that discharge from Labou Vallis (8.5S 154.5W) must have led to fluvial sedimentation in the planitia. We suggest that during locally non-lacustrine/ocean phases, this sedimentation would have occurred in the form of megafans. Megafans emanating from Marte, Mangala and Labou valles have probably contributed to hydrous near-subsurface environments--in their distal

  4. Inorganic Metal Oxide/Organic Polymer Nanocomposites And Method Thereof

    DOEpatents

    Gash, Alexander E.; Satcher, Joe H.; Simpson, Randy

    2004-11-16

    A synthetic method for preparation of hybrid inorganic/organic energetic nanocomposites is disclosed herein. The method employs the use of stable metal in organic salts and organic solvents as well as an organic polymer with good solubility in the solvent system to produce novel nanocomposite energetic materials. In addition, fuel metal powders (particularly those that are oxophilic) can be incorporated into composition. This material has been characterized by thermal methods, energy-filtered transmission electron microscopy (EFTEM), N.sub.2 adsoprtion/desorption methods, and Fourier-Transform (FT-IR) spectroscopy. According to these characterization methods the organic polymer phase fills the nanopores of the material, providing superb mixing of the component phases in the energetic nanocomposite.

  5. Homogeneous coating of photonic macroporous oxides with inorganic nanocrystals

    NASA Astrophysics Data System (ADS)

    Mitchell, Robert; Brydson, Rik; Douthwaite, R. E.

    2014-03-01

    A simple method to obtain homogeneous sub-monolayer coverage of metal oxide and chalcogenide nanocrystals onto porous oxide supports is described. Quantitative nanoparticle coverage was probed using photonic macroporous oxide supports. Composites of nanocrystals of TiO2, Fe3O4 or CdS dispersed onto macroporous SiO2 or ZrO2 all show a predictable linear shift in the photonic stop band position.A simple method to obtain homogeneous sub-monolayer coverage of metal oxide and chalcogenide nanocrystals onto porous oxide supports is described. Quantitative nanoparticle coverage was probed using photonic macroporous oxide supports. Composites of nanocrystals of TiO2, Fe3O4 or CdS dispersed onto macroporous SiO2 or ZrO2 all show a predictable linear shift in the photonic stop band position. Electronic supplementary information (ESI) available: Synthetic procedures, SEM, TEM, EDX, PXRD, DRUVS and BET measurements. See DOI: 10.1039/c4nr00490f

  6. Thermal stability of ladderane lipids as determined by hydrous pyrolysis

    USGS Publications Warehouse

    Jaeschke, A.; Lewan, M.D.; Hopmans, E.C.; Schouten, S.; Sinninghe, Damste J.S.

    2008-01-01

    Anaerobic ammonium oxidation (anammox) has been recognized as a major process resulting in loss of fixed inorganic nitrogen in the marine environment. Ladderane lipids, membrane lipids unique to anammox bacteria, have been used as markers for the detection of anammox in marine settings. However, the fate of ladderane lipids after sediment burial and maturation is unknown. In this study, anammox bacterial cell material was artificially matured by hydrous pyrolysis at constant temperatures ranging from 120 to 365 ??C for 72 h to study the stability of ladderane lipids during progressive dia- and catagenesis. HPLC-MS/MS analysis revealed that structural alterations of ladderane lipids already occurred at 120 ??C. At temperatures >140 ??C, ladderane lipids were absent and only more thermally stable products could be detected, i.e., ladderane derivatives in which some of the cyclobutane rings were opened. These diagenetic products of ladderane lipids were still detectable up to temperatures of 260 ??C using GC-MS. Thus, ladderane lipids are unlikely to occur in ancient sediments and sedimentary rocks, but specific diagenetic products of ladderane lipids will likely be present in sediments and sedimentary rocks of relatively low maturity (i.e., C31 hopane 22S/(22S + 22R) ratio 0.5). ?? 2008 Elsevier Ltd.

  7. Interactions of inorganic oxide nanoparticles with sewage biosolids.

    PubMed

    Rottman, Jeff; Shadman, Farhang; Sierra-Alvarez, Reyes

    2012-01-01

    The use of nanoparticles (NPs) in manufacturing continues to increase despite the growing concern over their potential environmental and health effects. Understanding the interaction of NPs and sewage sludge is crucial for determining the ultimate fate of NPs released to municipal wastewater treatment plants (WWTPs) as those interactions will determine whether the bulk of the material is retained in the sludge or released in the effluent stream. Analyzing the affinity of aluminum oxide, cerium oxide, and silicon oxide NPs, which are commonly used in semiconductor manufacturing processes, for biosolids used in municipal WWTPs provides a basis for estimating their removal efficiency. Batch studies were performed and the NPs were shown to partition onto the cellular surface. At the maximum equilibrium values tested (75-92 mg nanoparticles/L), the concentration of Al(2)O(3), CeO(2) and SiO(2) associated with the sludge was 137, 238, and 28 mg/g-sludge VSS, respectively. These results suggest that electrostatic interactions play a major role in determining NP association with biosolids.

  8. Pitfalls of assays devoted to evaluation of oxidative stress induced by inorganic nanoparticles.

    PubMed

    Tournebize, Juliana; Sapin-Minet, Anne; Bartosz, Grzegorz; Leroy, Pierre; Boudier, Ariane

    2013-11-15

    During the last years, there has been a remarkable increase in the use of inorganic nanoparticles (NP) in different applications, including consumer and medical products. Despite these promising applications, the extremely small size of NP allows them to penetrate cells, in which they can interact with intracellular structures causing serious side effects. A number of studies showed that NP cause adverse effects predominantly via induction of an oxidative stress - an imbalance between damaging oxidants and protective antioxidants - resulting in inflammation, immune response, cell damages, genotoxicity, etc … Most of the in vitro methods used for measurement of oxidative stress biomarkers were designed and standardized for conventional organic, inorganic and biochemical compounds. More recently, these methods have been adapted to studies related to various nanomaterials. Thus, this review is an attempt to highlight some current methods employed in and to provide a critical analysis of the major challenges and issues faced in this emerging field. PMID:24148470

  9. Time-resolved luminescence of nanocrystalline inorganic complex oxides

    NASA Astrophysics Data System (ADS)

    Pankratov, V.; Millers, D.; Grigorjeva, L.; Lojkowski, W.; Kareiva, A.

    2007-12-01

    Two types of complex nanosized oxides - cerium doped Y3Al5O12 (YAG) and CaWO4- have been studied by means of time-resolved luminescence spectroscopy. Comparative study of time-resolve luminescence characteristics of cerium doped YAG single crystal, nanopowders and nanoceramic as well as for CaWO4 macro- and nanocrystals has been done. Two components in the decay kinetic of Ce3+ related emission in YAG nanocrystals were detected and it was suggested that a different energy transfer rate to volume and surface Ce3+ ions takes place. It is shown that the segregation of Ce3+ ions near nanoparticles surface and/or dislocation lines plays a crucial role in degradation of light yield of cerium related luminescence in YAG nanocrystals. Time-resolved properties of sol-gel synthesized CaWO4 nanocrystals depends strongly on the synthesis rout. It was shown that shallow traps have a strong influence on the luminescence decay times of nanosized CaWO4.

  10. Genomic Analysis Unravels Reduced Inorganic Sulfur Compound Oxidation of Heterotrophic Acidophilic Acidicaldus sp. Strain DX-1

    PubMed Central

    Liu, Yuanyuan; Yang, Hongying; Zhang, Xian; Xiao, Yunhua; Guo, Xue; Liu, Xueduan

    2016-01-01

    Although reduced inorganic sulfur compound (RISC) oxidation in many chemolithoautotrophic sulfur oxidizers has been investigated in recent years, there is little information about RISC oxidation in heterotrophic acidophiles. In this study, Acidicaldus sp. strain DX-1, a heterotrophic sulfur-oxidizing acidophile, was isolated. Its genome was sequenced and then used for comparative genomics. Furthermore, real-time quantitative PCR was performed to identify the expression of genes involved in the RISC oxidation. Gene encoding thiosulfate: quinone oxidoreductase was present in Acidicaldus sp. strain DX-1, while no candidate genes with significant similarity to tetrathionate hydrolase were found. Additionally, there were genes encoding heterodisulfide reductase complex, which was proposed to play a crucial role in oxidizing cytoplasmic sulfur. Like many heterotrophic sulfur oxidizers, Acidicaldus sp. strain DX-1 had no genes encoding enzymes essential for the direct oxidation of sulfite. An indirect oxidation of sulfite via adenosine-5′-phosphosulfate was proposed in Acidicaldus strain DX-1. However, compared to other closely related bacteria Acidiphilium cryptum and Acidiphilium multivorum, which harbored the genes encoding Sox system, almost all of these genes were not detected in Acidicaldus sp. strain DX-1. This study might provide some references for the future study of RISC oxidation in heterotrophic sulfur-oxidizing acidophiles. PMID:27239474

  11. Genomic Analysis Unravels Reduced Inorganic Sulfur Compound Oxidation of Heterotrophic Acidophilic Acidicaldus sp. Strain DX-1.

    PubMed

    Liu, Yuanyuan; Yang, Hongying; Zhang, Xian; Xiao, Yunhua; Guo, Xue; Liu, Xueduan

    2016-01-01

    Although reduced inorganic sulfur compound (RISC) oxidation in many chemolithoautotrophic sulfur oxidizers has been investigated in recent years, there is little information about RISC oxidation in heterotrophic acidophiles. In this study, Acidicaldus sp. strain DX-1, a heterotrophic sulfur-oxidizing acidophile, was isolated. Its genome was sequenced and then used for comparative genomics. Furthermore, real-time quantitative PCR was performed to identify the expression of genes involved in the RISC oxidation. Gene encoding thiosulfate: quinone oxidoreductase was present in Acidicaldus sp. strain DX-1, while no candidate genes with significant similarity to tetrathionate hydrolase were found. Additionally, there were genes encoding heterodisulfide reductase complex, which was proposed to play a crucial role in oxidizing cytoplasmic sulfur. Like many heterotrophic sulfur oxidizers, Acidicaldus sp. strain DX-1 had no genes encoding enzymes essential for the direct oxidation of sulfite. An indirect oxidation of sulfite via adenosine-5'-phosphosulfate was proposed in Acidicaldus strain DX-1. However, compared to other closely related bacteria Acidiphilium cryptum and Acidiphilium multivorum, which harbored the genes encoding Sox system, almost all of these genes were not detected in Acidicaldus sp. strain DX-1. This study might provide some references for the future study of RISC oxidation in heterotrophic sulfur-oxidizing acidophiles. PMID:27239474

  12. CRYSTAL CHEMISTRY OF HYDROUS MINERALS

    SciTech Connect

    Y. ZHAO; ET AL

    2001-02-01

    Hydrogen has long been appreciated for its role in geological processes of the Earth's crust. However, its role in Earth's deep interior has been neglected in most geophysical thinking. Yet it is now believed that most of our planet's hydrogen may be locked up in high pressure phases of hydrous silicate minerals within the Earth's mantle. This rocky interior (approximately 7/8 of Earth's volume) is conjectured to contain 1-2 orders of magnitude more water than the more obvious oceans (the ''hydrosphere'') and atmosphere. This project is aimed at using the capability of neutron scattering from hydrogen to study the crystal chemistry and stability of hydrogen-bearing minerals at high pressures and temperatures. At the most basic level this is a study of the atomic position and hydrogen bond itself. We have conducted experimental runs on hydrous minerals under high pressure and high temperature conditions. The crystallographic structure of hydrous minerals at extreme conditions and its structural stability, and hydrogen bond at high P-T conditions are the fundamental questions to be addressed. The behavior of the hydrous minerals in the deep interior of the Earth has been discussed.

  13. Stoichiometric modeling of oxidation of reduced inorganic sulfur compounds (Riscs) in Acidithiobacillus thiooxidans.

    PubMed

    Bobadilla Fazzini, Roberto A; Cortés, Maria Paz; Padilla, Leandro; Maturana, Daniel; Budinich, Marko; Maass, Alejandro; Parada, Pilar

    2013-08-01

    The prokaryotic oxidation of reduced inorganic sulfur compounds (RISCs) is a topic of utmost importance from a biogeochemical and industrial perspective. Despite sulfur oxidizing bacterial activity is largely known, no quantitative approaches to biological RISCs oxidation have been made, gathering all the complex abiotic and enzymatic stoichiometry involved. Even though in the case of neutrophilic bacteria such as Paracoccus and Beggiatoa species the RISCs oxidation systems are well described, there is a lack of knowledge for acidophilic microorganisms. Here, we present the first experimentally validated stoichiometric model able to assess RISCs oxidation quantitatively in Acidithiobacillus thiooxidans (strain DSM 17318), the archetype of the sulfur oxidizing acidophilic chemolithoautotrophs. This model was built based on literature and genomic analysis, considering a widespread mix of formerly proposed RISCs oxidation models combined and evaluated experimentally. Thiosulfate partial oxidation by the Sox system (SoxABXYZ) was placed as central step of sulfur oxidation model, along with abiotic reactions. This model was coupled with a detailed stoichiometry of biomass production, providing accurate bacterial growth predictions. In silico deletion/inactivation highlights the role of sulfur dioxygenase as the main catalyzer and a moderate function of tetrathionate hydrolase in elemental sulfur catabolism, demonstrating that this model constitutes an advanced instrument for the optimization of At. thiooxidans biomass production with potential use in biohydrometallurgical and environmental applications.

  14. Thermochemistry of dense hydrous magnesium silicates

    NASA Technical Reports Server (NTRS)

    Bose, Kunal; Burnley, Pamela; Navrotsky, Alexandra

    1994-01-01

    Recent experimental investigations under mantle conditions have identified a suite of dense hydrous magnesium silicate (DHMS) phases that could be conduits to transport water to at least the 660 km discontinuity via mature, relatively cold, subducting slabs. Water released from successive dehydration of these phases during subduction could be responsible for deep focus earthquakes, mantle metasomatism and a host of other physico-chemical processes central to our understanding of the earth's deep interior. In order to construct a thermodynamic data base that can delineate and predict the stability ranges for DHMS phases, reliable thermochemical and thermophysical data are required. One of the major obstacles in calorimetric studies of phases synthesized under high pressure conditions has been limitation due to the small (less than 5 mg) sample mass. Our refinement of calorimeter techniques now allow precise determination of enthalpies of solution of less than 5 mg samples of hydrous magnesium silicates. For example, high temperature solution calorimetry of natural talc (Mg(0.99) Fe(0.01)Si4O10(OH)2), periclase (MgO) and quartz (SiO2) yield enthalpies of drop solution at 1044 K to be 592.2 (2.2), 52.01 (0.12) and 45.76 (0.4) kJ/mol respectively. The corresponding enthalpy of formation from oxides at 298 K for talc is minus 5908.2 kJ/mol agreeing within 0.1 percent to literature values.

  15. Thermochemistry of dense hydrous magnesium silicates

    NASA Astrophysics Data System (ADS)

    Bose, Kunal; Burnley, Pamela; Navrotsky, Alexandra

    Recent experimental investigations under mantle conditions have identified a suite of dense hydrous magnesium silicate (DHMS) phases that could be conduits to transport water to at least the 660 km discontinuity via mature, relatively cold, subducting slabs. Water released from successive dehydration of these phases during subduction could be responsible for deep focus earthquakes, mantle metasomatism and a host of other physico-chemical processes central to our understanding of the earth's deep interior. In order to construct a thermodynamic data base that can delineate and predict the stability ranges for DHMS phases, reliable thermochemical and thermophysical data are required. One of the major obstacles in calorimetric studies of phases synthesized under high pressure conditions has been limitation due to the small (less than 5 mg) sample mass. Our refinement of calorimeter techniques now allow precise determination of enthalpies of solution of less than 5 mg samples of hydrous magnesium silicates. For example, high temperature solution calorimetry of natural talc (Mg(0.99) Fe(0.01)Si4O10(OH)2), periclase (MgO) and quartz (SiO2) yield enthalpies of drop solution at 1044 K to be 592.2 (2.2), 52.01 (0.12) and 45.76 (0.4) kJ/mol respectively. The corresponding enthalpy of formation from oxides at 298 K for talc is minus 5908.2 kJ/mol agreeing within 0.1 percent to literature values.

  16. Mechanism of oxidation of inorganic sulfur compounds by thiosulfate-grown Thiobacillus thiooxidans.

    PubMed

    Masau, R J; Oh, J K; Suzuki, I

    2001-04-01

    Thiobacillus thiooxidans was grown at pH 5 on thiosulfate as an energy source, and the mechanism of oxidation of inorganic sulfur compounds was studied by the effect of inhibitors, stoichiometries of oxygen consumption and sulfur, sulfite, or tetrathionate accumulation, and cytochrome reduction by substrates. Both intact cells and cell-free extracts were used in the study. The results are consistent with the pathway with sulfur and sulfite as the key intermediates. Thiosulfate was oxidized after cleavage to sulfur and sulfite as intermediates at pH 5, the optimal growth pH on thiosulfate, but after initial condensation to tetrathionate at pH 2.3 where the organism failed to grow. N-Ethylmaleimide (NEM) inhibited sulfur oxidation directly and the oxidation of thiosulfate or tetrathionate indirectly. It did not inhibit the sulfite oxidation by cells, but inhibited any reduction of cell cytochromes by sulfur, thiosulfate, tetrathionate, and sulfite. NEM probably binds sulfhydryl groups, which are possibly essential in supplying electrons to initiate sulfur oxidation. 2-Heptyl-4-hydroxy-quinoline N-oxide (HQNO) inhibited the oxidation of sulfite directly and that of sulfur, thiosulfate, and tetrathionate indirectly. Uncouplers, carbonyl cyanide-m-chlorophenylhydrazone (CCCP) and 2,4-dinitrophenol (DNP), inhibited sulfite oxidation by cells, but not the oxidation by extracts, while HQNO inhibited both. It is proposed that HQNO inhibits the oxidation of sulfite at the cytochrome b site both in cells and extracts, but uncouplers inhibit the oxidation in cells only by collapsing the energized state of cells, delta muH+, required either for electron transfer from cytochrome c to b or for sulfite binding.

  17. Freezing-Enhanced Dissolution of Iron Oxides: Effects of Inorganic Acid Anions.

    PubMed

    Jeong, Daun; Kim, Kitae; Min, Dae Wi; Choi, Wonyong

    2015-11-01

    Dissolution of iron from mineral dust particles greatly depends upon the type and amount of copresent inorganic anions. In this study, we investigated the roles of sulfate, chloride, nitrate, and perchlorate on the dissolution of maghemite and lepidocrocite in ice under both dark and UV irradiation and compared the results with those of their aqueous counterparts. After 96 h of reaction, the total dissolved iron in ice (pH 3 before freezing) was higher than that in the aqueous phase (pH 3) by 6-28 times and 10-20 times under dark and UV irradiation, respectively. Sulfuric acid was the most efficient in producing labile iron under dark condition, whereas hydrochloric acid induced the most dissolution of the total and ferrous iron in the presence of light. This ice-induced dissolution result was also confirmed with Arizona Test Dust (AZTD). In the freeze-thaw cycling test, the iron oxide samples containing chloride, nitrate, or perchlorate showed a similar extent of total dissolved iron after each cycling while the sulfate-containing sample rapidly lost its dissolution activity with repeating the cycle. This unique phenomenon observed in ice might be related to the freeze concentration of protons, iron oxides, and inorganic anions in the liquid-like ice grain boundary region. These results suggest that the ice-enhanced dissolution of iron oxides can be a potential source of bioavailable iron, and the acid anions critically influence this process.

  18. Freezing-Enhanced Dissolution of Iron Oxides: Effects of Inorganic Acid Anions.

    PubMed

    Jeong, Daun; Kim, Kitae; Min, Dae Wi; Choi, Wonyong

    2015-11-01

    Dissolution of iron from mineral dust particles greatly depends upon the type and amount of copresent inorganic anions. In this study, we investigated the roles of sulfate, chloride, nitrate, and perchlorate on the dissolution of maghemite and lepidocrocite in ice under both dark and UV irradiation and compared the results with those of their aqueous counterparts. After 96 h of reaction, the total dissolved iron in ice (pH 3 before freezing) was higher than that in the aqueous phase (pH 3) by 6-28 times and 10-20 times under dark and UV irradiation, respectively. Sulfuric acid was the most efficient in producing labile iron under dark condition, whereas hydrochloric acid induced the most dissolution of the total and ferrous iron in the presence of light. This ice-induced dissolution result was also confirmed with Arizona Test Dust (AZTD). In the freeze-thaw cycling test, the iron oxide samples containing chloride, nitrate, or perchlorate showed a similar extent of total dissolved iron after each cycling while the sulfate-containing sample rapidly lost its dissolution activity with repeating the cycle. This unique phenomenon observed in ice might be related to the freeze concentration of protons, iron oxides, and inorganic anions in the liquid-like ice grain boundary region. These results suggest that the ice-enhanced dissolution of iron oxides can be a potential source of bioavailable iron, and the acid anions critically influence this process. PMID:26444653

  19. Ammonia-oxidizing archaea respond positively to inorganic nitrogen addition in desert soils.

    PubMed

    Marusenko, Yevgeniy; Garcia-Pichel, Ferran; Hall, Sharon J

    2015-02-01

    In soils, nitrogen (N) addition typically enhances ammonia oxidation (AO) rates and increases the population density of ammonia-oxidizing bacteria (AOB), but not that of ammonia-oxidizing archaea (AOA). We asked if long-term inorganic N addition also has similar consequences in arid land soils, an understudied yet spatially ubiquitous ecosystem type. Using Sonoran Desert top soils from between and under shrubs within a long-term N-enrichment experiment, we determined community concentration-response kinetics of AO and measured the total and relative abundance of AOA and AOB based on amoA gene abundance. As expected, N addition increased maximum AO rates and the abundance of bacterial amoA genes compared to the controls. Surprisingly, N addition also increased the abundance of archaeal amoA genes. We did not detect any major effects of N addition on ammonia-oxidizing community composition. The ammonia-oxidizing communities in these desert soils were dominated by AOA as expected (78% of amoA gene copies were related to Nitrososphaera), but contained unusually high contributions of Nitrosomonas (18%) and unusually low numbers of Nitrosospira (2%). This study highlights unique traits of ammonia oxidizers in arid lands, which should be considered globally in predictions of AO responses to changes in N availability.

  20. Synthesis and Characterization of a Layered Manganese Oxide: Materials Chemistry for the Inorganic or Instrumental Methods Lab

    ERIC Educational Resources Information Center

    Ching, Stanton; Neupane, Ram P.; Gray, Timothy P.

    2006-01-01

    A three-week laboratory project involving synthesis and characterization of a layered manganese oxide provides an excellent vehicle for teaching important concepts of inorganic chemistry and instrumental methods related to non-molecular systems. Na-birnessite is an easily prepared manganese oxide with a 7 A interlayer spacing and Na[superscript +]…

  1. Study of Organic and Inorganic Binders on Strength of Iron Oxide Pellets

    NASA Astrophysics Data System (ADS)

    Srivastava, Urvashi; Kawatra, S. Komar; Eisele, Timothy C.

    2013-08-01

    Bentonite is a predominant binder used in iron ore pelletization. However, the presence of a high content of silica and alumina in bentonite is considered undesirable for ironmaking operations. The objective of this study was to identify the alternatives of bentonite for iron ore pelletization. To achieve this goal, different types of organic and inorganic binders were utilized to produce iron oxide pellets. The quality of these iron oxide pellets was compared with pellets made using bentonite. All pellets were tested for physical strength at different stages of pelletization to determine their ability to survive during shipping and handling. The results show that organic binders such as lactose monohydrate, hemicellulose, and sodium lignosulfonate can provide sufficient strength to indurated pellets.

  2. Nano-sized nickel oxide powder synthesized by organic-inorganic solution route.

    PubMed

    Lee, Sang-Jin; Han, Young-Min; Jung, Choong-Hwan; Kwak, Ji-Yeon

    2013-02-01

    Nano-sized nickel oxide powders were synthesized by an organic-inorganic solution route employing polyvinyl alcohol (PVA) as an organic carrier. In this study, it was possible to control the physical properties of the nickel oxide powders by change of the PVA content. The experimental factors, such as the PVA content, heating temperature and time, were studied for the synthesis of nano crystalline powders. Nickel nitrate, (Ni(NO3)2, reagent grade) was used as a source of nickel cation. Once the cation source was completely dissolved in de-ionized (DI) water, 5 wt% PVA solution was added to the sol solution. The resulting gel-type precursors were completely dried and then calcined or crystallized at various temperatures in an air atmosphere in a box furnace. In the high PVA content of 2:1 mixing ratio, nano crystallite nickel oxide powders of below 5 nm in size with a high specific surface area of 151.19 m2/g were obtained at low temperature of 400 degrees C for 1 h. The PVA polymer contributed to homogeneous nickel cations in atomic scale through the fabrication process of the sol precursor. In this paper, the PVA solution technique for the fabrication of nano-sized nickel oxide powders is introduced. The effects of PVA content and heating time on the powder crystallization, morphology and specific surface area are also studied. The characterization of the synthesized powders is examined by using XRD, DTA/TG, TEM and nitrogen gas adsorption.

  3. Response of anaerobic ammonium oxidation to inorganic nitrogen fluctuations in temperate estuarine sediments

    NASA Astrophysics Data System (ADS)

    Teixeira, Catarina; Magalhães, Catarina; Joye, Samantha B.; Bordalo, Adriano A.

    2016-07-01

    The discovery of anaerobic ammonium oxidation (anammox) highlighted the importance of alternative metabolic pathways to inorganic nitrogen removal in natural environments, particularly in those subjected to increased nitrate inputs, such as estuaries. Laboratory enrichment experiments were used to test the effect of increasing loads of nitrate (NO3-), nitrite (NO2-), and ammonium (NH4+) on the anammox process. Three Atlantic temperate estuaries (NW Portugal) were investigated along a salinity gradient, and anammox activity was measured under different NO3-, NO2-, and NH4+ treatments, using the isotope pairing technique. Obtained results showed that NO3- stimulated denitrification but not anammox, whereas NO2- additions had a positive effect on anammox activity, confirming its role as a key environmental control. On the other hand, increasing NH4+ concentrations seemed to inhibit anammox for low salinity sites. Our findings suggested an important role of the natural availability of nitrogen compounds in regulating anammox and the magnitude of anammox versus denitrification in estuarine environments.

  4. A systematic investigation of the preparation and properties of composite carbon molecular sieves containing inorganic oxides

    NASA Technical Reports Server (NTRS)

    Foley, Henry C.

    1990-01-01

    The objective of this research is to define the methodology for the preparation and characterization of new carbon-based molecular sieves with composite structures. Carbon molecular sieves have found increasing application in the field of separation and purification of gases. These materials are relatively easy to prepare and their surfaces can be modified to some extent. It is expected that by combining inorganic oxides with the carbonaceous structure one can begin to design composite materials with a wider range of possible chemical and physical properties. In this way, the IOM-CMS materials may confer distinct advantages over pure carbon molecular sieves, not just for separation, but also for catalysis. The most recent results in the design and characterization of these IOM-CMS materials are reviewed and summarized. Directions for further research are also presented.

  5. Well-ordered organic-inorganic hybrid layered manganese oxide nanocomposites with excellent decolorization performance

    SciTech Connect

    Zhou, Junli; Yu, Lin; Sun, Ming; Ye, Fei; Lan, Bang; Diao, Guiqiang; He, Jun

    2013-02-15

    Well-ordered organic-inorganic hybrid layered manganese oxide nanocomposites (CTAB-Al-MO) with excellent decolorization performance were prepared through a two-step process. Specifically, the MnO{sub 2} nanosheets were self-assembled in the presence of CTAB, and subsequently pillared with Keggin ions. The obtained CTAB-Al-MO with the basal spacing of 1.59 nm could be stable at 300 Degree-Sign C for 2 h and also possesses high total pore volumes (0.41 cm Superscript-Three g{sup -1}) and high specific BET surface area (161 m{sup 2} g{sup -1}), which is nine times larger than that of the pristine (19 m{sup 2} g{sup -1}). Possible formation process for the highly thermal stable CTAB-Al-MO is proposed here. The decolorization experiments of methyl orange showed that the obtained CTAB-Al-MO exhibit excellent performance in wastewater treatment and the decolorization rate could reach 95% within 5 min. - Graphical Abstract: Well-ordered organic-inorganic hybrid LMO nanocomposites (CTAB-Al-MO) with excellent decolorization performance were prepared through a two-step process. Specifically, the MnO{sub 2} nanosheets were self-assembled by CTAB, and subsequently pillared with Keggin ions. Highlights: Black-Right-Pointing-Pointer A two-step synthesis method was used to prepare the CTAB-Al-MO. Black-Right-Pointing-Pointer The CTAB-Al-MO has the large basal spacing and high specific BET surface area. Black-Right-Pointing-Pointer The thermal stability of the well-ordered CTAB-Al-MO could obviously improve. Black-Right-Pointing-Pointer The CTAB-Al-MO exhibits excellent oxidation and absorption ability to remove organic pollutants.

  6. Compilation, evaluation, and prediction of triple-layer model constants for ions on Fe(III) and Mn(IV) hydrous oxides

    SciTech Connect

    Smith, R.W.; Jenne, E.A.

    1988-11-01

    This report includes recommendations for further work. A brief discussion of the formulation of the Triple Layer Model (TLM) of the oxide/water interfaces is given in Section 3. Table of literature values for TLM constants are given in Section 4.0. In addition, the sources of uncertainties in the TLM constants are discussed. Equations useful for the prediction of TLM parameters are presented in Section 6.0. Summaries of experimental conditions used by the various investigators referenced in this report are given in Appendix A. 43 refs., 4 figs., 12 tabs. (JL)

  7. The role of hydrous ferric oxide precipitation in the fractionation of arsenic, gallium, and indium during the neutralization of acidic hot spring water by river water in the Tama River watershed, Japan

    NASA Astrophysics Data System (ADS)

    Ogawa, Yasumasa; Ishiyama, Daizo; Shikazono, Naotatsu; Iwane, Kenta; Kajiwara, Masahiro; Tsuchiya, Noriyoshi

    2012-06-01

    The Obuki spring is the largest and most acidic of the Tamagawa hot springs (Akita Prefecture, northern Japan), and it discharges ca. 9000 L/min of chloride-rich acidic water (pH 1.2) that contains high concentrations of both As and rare metals such as Ga and In. This paper aims to quantify seasonal variations in the mobility of these elements in the Shibukuro and Tama rivers, which are fed by the thermal waters of the Obuki spring, caused by sorption onto hydrous ferric oxide (HFO). Seasonal observations revealed the following relationships with respect to As removal by HFO: (a) the oxidation of Fe2+ is predominantly controlled by both pH and water temperature, and progresses more quickly in less acidic and warmer conditions; (b) HFO formation was predominantly controlled by pH; and (c) the removal of dissolved arsenate is directly related to the amount of HFO present. Consequently, the oxidation to Fe3+ was slower during periods of cold and lower pH, and the amount of HFO was too small to remove the dissolved arsenate effectively. Consequently, considerable amounts of dissolved arsenate and Fe2+ remained in river water. In contrast, when HFO production from Fe3+ increased, and dissolved arsenate was removed during warmer and less acidic periods, only small amounts of dissolved arsenite and Fe2+ remained in the river water. The geochemical behavior of Ga and In was essentially controlled by pH; however, when HFO production was limited by a pH of less than 3.5, Ga behavior was controlled mainly by the amount of HFO. Gallium tended to be sorbed under more acidic conditions than was In. Due to differences in sorption behavior, Ga, As, and In were fractionated during sedimentation. In the upstream reaches, arsenate and dissolved Ga sorbed onto HFO, and were widely distributed across the watershed. Conversely, dissolved In was removed by HFO downstream. As a result, In is relatively concentrated on the downstream lakebed, unlike As and Ga, and In-rich mineral deposits

  8. RNA transcript sequencing reveals inorganic sulfur compound oxidation pathways in the acidophile Acidithiobacillus ferrivorans.

    PubMed

    Christel, Stephan; Fridlund, Jimmy; Buetti-Dinh, Antoine; Buck, Moritz; Watkin, Elizabeth L; Dopson, Mark

    2016-04-01

    Acidithiobacillus ferrivorans is an acidophile implicated in low-temperature biomining for the recovery of metals from sulfide minerals. Acidithiobacillus ferrivorans obtains its energy from the oxidation of inorganic sulfur compounds, and genes encoding several alternative pathways have been identified. Next-generation sequencing of At. ferrivorans RNA transcripts identified the genes coding for metabolic and electron transport proteins for energy conservation from tetrathionate as electron donor. RNA transcripts suggested that tetrathionate was hydrolyzed by the tetH1 gene product to form thiosulfate, elemental sulfur and sulfate. Despite two of the genes being truncated, RNA transcripts for the SoxXYZAB complex had higher levels than for thiosulfate quinone oxidoreductase (doxDAgenes). However, a lack of heme-binding sites in soxX suggested that DoxDA was responsible for thiosulfate metabolism. Higher RNA transcript counts also suggested that elemental sulfur was metabolized by heterodisulfide reductase (hdrgenes) rather than sulfur oxygenase reductase (sor). The sulfite produced as a product of heterodisulfide reductase was suggested to be oxidized by a pathway involving the sat gene product or abiotically react with elemental sulfur to form thiosulfate. Finally, several electron transport complexes were involved in energy conservation. This study has elucidated the previously unknown At. ferrivorans tetrathionate metabolic pathway that is important in biomining.

  9. Iodine oxide in the global marine boundary layer: inorganic versus organic sources

    NASA Astrophysics Data System (ADS)

    Prados-Roman, Cristina; Cuevas, Carlos; Mahajan, Anoop; Fernandez, Rafael; Saiz-Lopez, Alfonso

    2014-05-01

    In the last decades iodine has been object of increasing interest in atmospheric chemistry due to its link to the oxidizing capacity of the atmosphere, the NOx and HOx partitioning and the formation of ultra-fine particles. Recently laboratory and numerous fieldwork efforts have been carried out trying to assess the sources and sinks of reactive iodine in the open marine environment. Within the framework of the Malaspina expedition, in 2010-2011 the Spanish research vessel Hesperides circumnavigated the world aiming at investigating the biogeochemistry, physical oceanography and microbiological biodiversity of the oceans from a multidisciplinary approach. During that 7-months campaign throughout the Atlantic, Indian and Pacific oceans, a MAX-DOAS system was deployed, along with a surface ozone instrument, in order to monitor the geographical distribution of relevant reactive iodine compounds such IO. Complementing this extensive dataset with results from previous works in the Eastern Pacific Ocean, we show not only the ubiquity of iodine oxide in the open marine boundary layer (MBL) ranging between 0.3-1 pptv levels, but also provide what is- to our knowledge- the most comprehensive global map of the of IO and O3 distribution in the subpolar MBL. Ultimately, by means of a photochemical model, we will address the contribution of inorganic and organic iodine sources to the measured levels of IO.

  10. Development and testing of inorganic sorbents made by the internal gelation process for radionuclide and heavy metal separations

    SciTech Connect

    Egan, B.Z.; Collins, J.L.; Anderson, K.K.; Chase, C.W.

    1995-11-29

    The objectives of this task are to develop, prepare, and test microspheres and granular forms of inorganic ion exchangers to remove radionuclides and heavy metals from waste streams occurring at various sites. Several inorganic materials, such as hexacyanoferrates, titanates, phosphates, and oxides have high selectivities and efficiencies for separating and removing radionuclides such as uranium, technetium, cesium, and strontium, and metals such as cobalt, silver, zinc, and zirconium from aqueous waste streams. However, these sorbents frequently exist only as powders and consequently are not readily adaptable to continuous processing such as column chromatography. Making these inorganic ion exchangers as microspheres or granular forms improves the flow dynamics for column operations and expands their practical applications. Microspheres of several materials have been prepared at ORNL, and the effectiveness of zirconium monohydrogen phosphate and hydrous titanium oxide microspheres for removing radionuclides from hot cell waste solutions has been demonstrated.

  11. Electrical Properties of Hydrous Magmas

    NASA Astrophysics Data System (ADS)

    Laumonier, M.; Sifre, D.; Gaillard, F.

    2013-12-01

    Volatiles strongly affect physical and chemical properties of magmas which are major vectors of mass and heat transfer in the Earth's. In subduction zones, hydrated melts prevail during the entire course of differentiation from basalts, andesites, dacites to rhyolites. Several electrical surveys obtained by magneto telluric investigations are currently deployed at subduction zones. The electrical conductivity of hydrous melts is however poorly constrained: so far only three studies have experimentally addressed this topic. Here, we show in situ electrical impedance of natural dacites, andesites (from Uturuncu Volcano, Bolivia) and basaltic magmas obtained with a 4-wire set up in a piston cylinder and internally heated pressure vessel. The range of temperature (500 to 1300°C), pressure (0.3 to 2 Gpa), and the various water contents and crystal fractions covers the respective ranges occurring at natural conditions. First results show that the conductivity increases with the temperature, the melt fraction, and a slightly decreases with the pressure and the crystal fraction. The compilation of these results with previous studies (rhyolitic, phonolitic and basaltic compositions) will lead to a general model of the electrical properties of magmas. Such a model will help in (i) interpreting the electrical signature of natural magmas and (ii) constraining their conditions (chemical composition, temperature, pressure, water content, melt fraction) from the source to the storage location.

  12. Nitric oxide induces the alternative oxidase pathway in Arabidopsis seedlings deprived of inorganic phosphate.

    PubMed

    Royo, Beatriz; Moran, Jose F; Ratcliffe, R George; Gupta, Kapuganti J

    2015-10-01

    Phosphate starvation compromises electron flow through the cytochrome pathway of the mitochondrial electron transport chain, and plants commonly respond to phosphate deprivation by increasing flow through the alternative oxidase (AOX). To test whether this response is linked to the increase in nitric oxide (NO) production that also increases under phosphate starvation, Arabidopsis thaliana seedlings were grown for 15 d on media containing either 0 or 1mM inorganic phosphate. The effects of the phosphate supply on growth, the production of NO, respiration, the AOX level and the production of superoxide were compared for wild-type (WT) seedlings and the nitrate reductase double mutant nia. Phosphate deprivation increased NO production in WT roots, and the AOX level and the capacity of the alternative pathway to consume electrons in WT seedlings; whereas the same treatment failed to stimulate NO production and AOX expression in the nia mutant, and the plants had an altered growth phenotype. The NO donor S-nitrosoglutathione rescued the growth phenotype of the nia mutants under phosphate deprivation to some extent, and it also increased the respiratory capacity of AOX. It is concluded that NO is required for the induction of the AOX pathway when seedlings are grown under phosphate-limiting conditions. PMID:26163703

  13. Alkyl Surface Treatments of Planar Zinc Oxide in Hybrid Organic/Inorganic Solar Cells

    SciTech Connect

    Allen, C. G.; Baker, D. J.; Brenner, T. M.; Weigand, C. C.; Albin, J. M.; Steirer, K. X.; Olson, D. C.; Ladam, C.; Ginley, D. S.; Collins, R. T.; Furtak, T. E.

    2012-04-26

    Hybrid organic/inorganic solar cells have not lived up to their potential because of poor interface properties. Interfacial molecular layers provide a way of adjusting these devices to improve their performance. We have studied a prototypical system involving poly(3-hexylthiophene) (P3HT) on planar zinc oxide (ZnO) films that have been modified with two types of molecules having identical 18-carbon alkyl chain termination and different surface attachments: octadecanethiol (ODT) and octadecyltriethoxysilane (OTES). We examined the functionalized surfaces using water contact angle measurements, Kelvin probe measurements, infrared absorbance spectroscopy, and atomic force microscopy. These have shown that OTES forms disordered incomplete monolayers, while ODT is prone to develop multilayered islands. Both treatments enhance polymer ordering. However, inverted solar cell devices fabricated with these treated interfaces performed very differently. ODT improves the short circuit current (J{sub SC}), open circuit voltage (V{sub OC}), and power conversion efficiency ({eta}), while these parameters all decrease in devices constructed from OTES-treated ZnO. The differences in V{sub OC} are related to modifications of the surface dipole associated with deposition of the two types of alkyl molecules, while changes in J{sub SC} are attributed to a balance between charge transfer blocking caused by the saturated hydrocarbon and the improved hole mobility in the polymer.

  14. Design and development of anisotropic inorganic/polystyrene nanocomposites by surface modification of zinc oxide nanoparticles.

    PubMed

    Han, Xiao; Huang, Shiming; Wang, Yilong; Shi, Donglu

    2016-07-01

    Anisotropic yolk/shell or Janus inorganic/polystyrene nanocomposites were prepared by combining miniemulsion polymerization and sol-gel reaction. The morphologies of the anisotropic composites were found to be greatly influenced by surface modification of zinc oxide (ZnO) nanoparticle seeds. Two different types of the oleic acid modified ZnO nanoparticles (OA-ZnO) were prepared by post-treatment of commercial ZnO powder and homemade OA-ZnO nanoparticles. The morphologies and properties of the nanocomposites were investigated by transmission electron microscope (TEM), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), dynamic light scattering (DLS), and energy dispersive X-ray spectroscopy (EDX). It was found that both post-treated OA-ZnO and in-situ prepared OA-ZnO nanoparticles resulted in the yolk-shell and Janus structure nanocomposites, but with varied size and morphology. These nanocomposites showed stable and strong fluorescence by introducing quantum dots as the co-seeds. The fluorescent anisotropic nanocomposites were decorated separately with surface carboxyl and hydroxyl groups. These composites with unique anisotropic properties will have high potential in biomedical applications, particularly in bio-detection.

  15. Nitric oxide induces the alternative oxidase pathway in Arabidopsis seedlings deprived of inorganic phosphate

    PubMed Central

    Royo, Beatriz; Moran, Jose F.; Ratcliffe, R. George; Gupta, Kapuganti J.

    2015-01-01

    Phosphate starvation compromises electron flow through the cytochrome pathway of the mitochondrial electron transport chain, and plants commonly respond to phosphate deprivation by increasing flow through the alternative oxidase (AOX). To test whether this response is linked to the increase in nitric oxide (NO) production that also increases under phosphate starvation, Arabidopsis thaliana seedlings were grown for 15 d on media containing either 0 or 1mM inorganic phosphate. The effects of the phosphate supply on growth, the production of NO, respiration, the AOX level and the production of superoxide were compared for wild-type (WT) seedlings and the nitrate reductase double mutant nia. Phosphate deprivation increased NO production in WT roots, and the AOX level and the capacity of the alternative pathway to consume electrons in WT seedlings; whereas the same treatment failed to stimulate NO production and AOX expression in the nia mutant, and the plants had an altered growth phenotype. The NO donor S-nitrosoglutathione rescued the growth phenotype of the nia mutants under phosphate deprivation to some extent, and it also increased the respiratory capacity of AOX. It is concluded that NO is required for the induction of the AOX pathway when seedlings are grown under phosphate-limiting conditions. PMID:26163703

  16. Methylarsonous acid causes oxidative DNA damage in cells independent of the ability to biomethylate inorganic arsenic

    PubMed Central

    Tokar, Erik J.; Kojima, Chikara; Waalkes, Michael P.

    2013-01-01

    Inorganic arsenic (iAs) and its toxic methylated metabolite, methylarsonous acid (MMAIII), both have carcinogenic potential. Prior study shows iAs induced malignant transformation in both arsenic methylation-proficient (liver) and methylation-deficient (prostate) cells, but only methylation-proficient cells show oxidative DNA damage (ODD) during this transformation. To further define if arsenic methylation is necessary for transformation or ODD induction, here we chronically exposed these same liver or prostate cell lines to MMAIII (0.25–1.0 μM) and tested for acquired malignant phenotype. Various metrics of oncogenic transformation were periodically assessed along with ODD during chronic MMAIII exposure. Methylation-deficient and methylation-proficient cells both acquired a cancer phenotype with MMAIII exposure at about 20 weeks, based on increased matrix metalloproteinase secretion, colony formation and invasion. In contrast, prior work showed iAs-induced transformation took longer in biomethylation-deficient cells (~30 weeks) than in biomethylation-proficient cells (~18 weeks). In the present study, MMAIII caused similar peak ODD levels at similar concentrations and at similar exposure times (18–22 weeks) in both cell types. At the approximate peak of ODD production both cell types showed similar alterations in arsenic and oxidative stress adaptation factors (i.e. ABCC1, ABCC2, GST-π, SOD-1). Thus, MMAIII causes oncogenic transformation associated with ODD in methylation-deficient cells, indicating further methylation is not required to induce ODD. Together, these results show that, MMAIII and iAs cause an acquired malignant phenotype in methylation-deficient cells, yet iAs does not induce ODD. This indicates iAs likely has both genotoxic and non-genotoxic mechanisms dictated by the target cell’s ability to methylate arsenic. PMID:24091636

  17. Methylarsonous acid causes oxidative DNA damage in cells independent of the ability to biomethylate inorganic arsenic.

    PubMed

    Tokar, Erik J; Kojima, Chikara; Waalkes, Michael P

    2014-02-01

    Inorganic arsenic (iAs) and its toxic methylated metabolite, methylarsonous acid (MMA(III)), both have carcinogenic potential. Prior study shows iAs-induced malignant transformation in both arsenic methylation-proficient (liver) and methylation-deficient (prostate) cells, but only methylation-proficient cells show oxidative DNA damage (ODD) during this transformation. To further define whether arsenic methylation is necessary for transformation or ODD induction, here we chronically exposed these same liver or prostate cell lines to MMA(III) (0.25-1.0 μM) and tested for acquired malignant phenotype. Various metrics of oncogenic transformation were periodically assessed along with ODD during chronic MMA(III) exposure. Methylation-deficient and methylation-proficient cells both acquired a cancer phenotype with MMA(III) exposure at about 20 weeks, based on increased matrix metalloproteinase secretion, colony formation, and invasion. In contrast, prior work showed iAs-induced transformation took longer in biomethylation-deficient cells (~30 weeks) than in biomethylation-proficient cells (~18 weeks). In the present study, MMA(III) caused similar peak ODD levels at similar concentrations and at similar exposure times (18-22 weeks) in both cell types. At the approximate peak of ODD production, both cell types showed similar alterations in arsenic and oxidative stress adaptation factors (i.e., ABCC1, ABCC2, GST-π, SOD-1). Thus, MMA(III) causes oncogenic transformation associated with ODD in methylation-deficient cells, indicating that further methylation is not required to induce ODD. Together, these results show that MMA(III) and iAs cause an acquired malignant phenotype in methylation-deficient cells, yet iAs does not induce ODD. This indicates iAs likely has both genotoxic and non-genotoxic mechanisms dictated by the target cell's ability to methylate arsenic. PMID:24091636

  18. Methylarsonous acid causes oxidative DNA damage in cells independent of the ability to biomethylate inorganic arsenic.

    PubMed

    Tokar, Erik J; Kojima, Chikara; Waalkes, Michael P

    2014-02-01

    Inorganic arsenic (iAs) and its toxic methylated metabolite, methylarsonous acid (MMA(III)), both have carcinogenic potential. Prior study shows iAs-induced malignant transformation in both arsenic methylation-proficient (liver) and methylation-deficient (prostate) cells, but only methylation-proficient cells show oxidative DNA damage (ODD) during this transformation. To further define whether arsenic methylation is necessary for transformation or ODD induction, here we chronically exposed these same liver or prostate cell lines to MMA(III) (0.25-1.0 μM) and tested for acquired malignant phenotype. Various metrics of oncogenic transformation were periodically assessed along with ODD during chronic MMA(III) exposure. Methylation-deficient and methylation-proficient cells both acquired a cancer phenotype with MMA(III) exposure at about 20 weeks, based on increased matrix metalloproteinase secretion, colony formation, and invasion. In contrast, prior work showed iAs-induced transformation took longer in biomethylation-deficient cells (~30 weeks) than in biomethylation-proficient cells (~18 weeks). In the present study, MMA(III) caused similar peak ODD levels at similar concentrations and at similar exposure times (18-22 weeks) in both cell types. At the approximate peak of ODD production, both cell types showed similar alterations in arsenic and oxidative stress adaptation factors (i.e., ABCC1, ABCC2, GST-π, SOD-1). Thus, MMA(III) causes oncogenic transformation associated with ODD in methylation-deficient cells, indicating that further methylation is not required to induce ODD. Together, these results show that MMA(III) and iAs cause an acquired malignant phenotype in methylation-deficient cells, yet iAs does not induce ODD. This indicates iAs likely has both genotoxic and non-genotoxic mechanisms dictated by the target cell's ability to methylate arsenic.

  19. Sulfide and sulfate saturation in hydrous silicate melts

    NASA Astrophysics Data System (ADS)

    Carroll, M. R.; Rutherford, M. J.

    1985-02-01

    A series of hydrothermal experiments was performed over a wide range of pressures, temperatures, oxygen fugacities, and melt FeO content, in order to examine the effects of physical changes on sulfur solubility in fractionated hydrous silicate melts. On the basis of the experimental results, it is concluded that upper crustal oxidation-reduction reactions and crystal fractionation processes may exert considerable influence on the amount of sulfur contained in magmas erupted at the surface. The application of the experimental results to investigations of volatile transport and volcanic degassing processes on the earth, Venus, and Mars is discussed

  20. Sulfide and sulfate saturation in hydrous silicate melts

    NASA Technical Reports Server (NTRS)

    Carroll, M. R.; Rutherford, M. J.

    1985-01-01

    A series of hydrothermal experiments was performed over a wide range of pressures, temperatures, oxygen fugacities, and melt FeO content, in order to examine the effects of physical changes on sulfur solubility in fractionated hydrous silicate melts. On the basis of the experimental results, it is concluded that upper crustal oxidation-reduction reactions and crystal fractionation processes may exert considerable influence on the amount of sulfur contained in magmas erupted at the surface. The application of the experimental results to investigations of volatile transport and volcanic degassing processes on the earth, Venus, and Mars is discussed

  1. Acid catalyzed hydrocarbon conversion processes utilizing a catalyst comprising a group ivb, vb or vib metal oxide on an inorganic refractory oxide support

    SciTech Connect

    Grenoble, D.C.; Kim, C.J.; Murrell, L.L.

    1980-11-11

    It has been discovered and forms the basis of the disclosure that various acid catalyzed hydrocarbon conversion processes such as catalytic cracking of gas oil; xylene isomerization; toluene disproportionation; dealkylation of aromatics; ethylene, butylene , isobutylene, propylene polymerization; olefin isomerization; alcohol dehydration; olefin hydration; alkylation; heavy ends cat cracking, etc. are dramatically improved insofar as percent conversion, and selectivity are concerned by the use of a catalyst selected from the group consisting of the oxides of tungsten, niobium and mixtures thereof, and tungsten or niobium oxides in combination with one or more additional metal oxides selected from the group consisting of tantalum oxide, hafnium oxide, chromium oxide, titanium oxide and zirconium oxide, supported on an inorganic refractory oxide support. These catalysts may be prepared by the methods known in the art, I.E., incipient wetness, impregnation, coprecipitation, etc. Of the metal oxide precursor onto or with the supports followed by conversion into the oxide form. Before use, the metal oxide/support combination is preferably subjected to steaming at elevated temperatures either before introduction into the reactor or in situ in the process reactor. Conventional catalytic cracking catalysts are unstable at the elevated temperatures where the metal oxide/support combinations of the present invention are uniquely stable.

  2. Inorganic arsenic causes cell apoptosis in mouse cerebrum through an oxidative stress-regulated signaling pathway.

    PubMed

    Yen, Cheng Chien; Ho, Tsung Jung; Wu, Chin Ching; Chang, Chun Fang; Su, Chin Chuan; Chen, Ya Wen; Jinn, Tzyy Rong; Lu, Tien Hui; Cheng, Po Wen; Su, Yi Chang; Liu, Shing Hwa; Huang, Chun Fa

    2011-06-01

    Arsenic pollution is a major public health problem worldwide. Inorganic arsenic (iAs) is usually more harmful than organic ones. iAs pollution increases the risk of human diseases such as peripheral vascular disease and cancer. However, the toxicological effects of iAs in the brain are mostly unclear. Here, we investigated the toxic effects and possible mechanisms of iAs in the cerebrum of mice after exposure to iAs (0.5 and 5 ppm (mg/l) As(2)O(3), via the drinking water), which was the possible human exposed dose via the ingestion in iAs-contaminated areas, for 6 consecutive weeks. iAs dose-dependently caused an increase of LPO production in the plasma and cerebral cortex. iAs also decreased the reduced glutathione levels and the expressions of NQO1 and GPx mRNA in the cerebral cortex. These impairments in the cerebral cortex caused by iAs exposure were significantly correlated with the accumulation of As. Moreover, iAs induced the production of apoptotic cells and activation of caspase-3, up-regulation of Bax and Bak, and down-regulation of Mcl-1 in the cerebral cortex. Exposure to iAs also triggered the expression of ER stress-related genes, including GRP78, GRP94, and CHOP. Meanwhile, an increase of p38 activation and dephosphorylation of ERK1/2 were shown in the cerebral cortex as a result of iAs-exposed mice. These iAs-induced damages and apoptosis-related signals could be significantly reversed by NAC. Taken together, these results suggest that iAs-induced oxidative stress causes cellular apoptosis in the cerebrum, signaling of p38 and ERK1/2, and ER stress may be involved in iAs-induced cerebral toxicity.

  3. ARSENIC (+3 OXIDATION STATE) METHYLTRANSFERASE AND THE INORGANIC ARSENIC METHYLATION PHENOTYPE

    EPA Science Inventory

    Inorganic arsenic is enzymatically methylated; hence, its ingestion results in exposure to the parent compound and various methylated arsenicals. Both experimental and epidemiological evidence suggest that some of the adverse health effects associated with chronic exposure to in...

  4. Effects of inhibitors and NaCl on the oxidation of reduced inorganic sulfur compounds by a marine acidophilic, sulfur-oxidizing bacterium, Acidithiobacillus thiooxidans strain SH.

    PubMed

    Kamimura, Kazuo; Higashino, Emi; Kanao, Tadayoshi; Sugio, Tsuyoshi

    2005-02-01

    The effect of NaCl and the pathways of the oxidation of reduced inorganic sulfur compounds were studied using resting cells and cell-free extracts of Acidithiobacillus thiooxidans strain SH. This isolate specifically requires NaCl for growth. The oxidation of sulfur and sulfite by resting cells was strongly inhibited by 2-heptyl-4-hydroxyquinoline-N-oxide. Carbonylcyanide m-chlorophenyl-hydrazone and monensin were also relatively strong inhibitors. Thiosulfate-oxidizing activity was not inhibited by these uncouplers. Valinomycin did not inhibit the oxidation of sulfur compounds. NaCl stimulated the sulfur- and sulfite-oxidizing activities in resting cells but not in cell-free extracts. The tetrathionate-oxidizing activity in resting cells was slightly stimulated by NaCl, whereas it did not influence the thiosulfate-oxidizing activity. Sulfide oxidation was biphasic, suggesting the formation of intermediate sulfur. The initial phase of sulfide oxidation was not affected by NaCl, whereas the subsequent oxidation of sulfur in the second phase was Na+-dependent. A model is proposed for the role of NaCl in the metabolism of reduced sulfur compounds in A. thiooxidans strain SH.

  5. Nb-Ta, Nb-Mo and Nb-V oxides prepared from hybrid organic-inorganic precursors

    SciTech Connect

    Deligne, N.; Bayot, D.; Degand, M.; Devillers, M.

    2007-07-15

    New hybrid organic-inorganic materials based on group 5 elements and a well-defined polymeric matrix have been prepared and used as precursors for Nb-Ta and Nb-Mo mixed oxides. In this non-conventional but easily accessible route to multimetallic oxides, a copolymer of N,N-diallyl-N-hexylamine and maleic acid was synthesised and used as matrix to stabilise inorganic species generated in solution from (NH{sub 4}){sub 6}Mo{sub 7}O{sub 24}.4H{sub 2}O, NH{sub 4}VO{sub 3} (gu){sub 3}[Nb(O{sub 2}){sub 4}] and (gu){sub 3}[Ta(O{sub 2}){sub 4}]. Solid-state studies indicate that the homogeneity of the blends can be kept up to about 0.5 mol Nb{sup V} and Ta{sup V} and 0.25 mol V{sup V} per mol of repeat units of the copolymer. The calcination conditions of these homogeneous hybrid precursors were optimised to produce Nb-Mo, Nb-Ta and Nb-V oxides. While the thermal treatment of the Nb-V hybrid blends led only to a mixture of different phases, the characterisation of the final phases by X-ray diffraction (XRD) proved the formation of pure Nb{sub 2}Mo{sub 3}O{sub 14} and showed that Nb-Ta oxides could be synthesised as single phases corresponding to a continuous series of solid solutions. - Graphical abstract: An alternative route based on hybrid organic-inorganic materials was implemented to synthesise Nb-Ta, Nb-Mo and Nb-V oxides. The hybrid materials were prepared by incorporation of inorganic salts based on Nb{sup V}, Ta{sup V}, V{sup V} and Mo{sup VI} in an organic polymer bearing cationic as well as anionic moieties. A thermal treatment of these hybrid blends has allowed the formation of multimetallic oxides.

  6. PEGylated Inorganic Nanoparticles

    SciTech Connect

    Karakoti, Ajay S.; Das, Soumya; Thevuthasan, Suntharampillai; Seal, Sudipta

    2011-02-25

    Application of inorganic nanoparticles in diagnosis and therapy has become a critical component in targeted treatment of diseases. The surface modification of inorganic oxides is important for providing diversity in size, shape, solubility, long term stability and attachment of selective functional groups. PEGylation of surfaces is a key strategic approach for providing stealth characteristics to nanomaterials otherwise identified as foreign materials by human body. The current review describes the role of surface modification of oxides by polyethylene glycol (PEG) in providing versatile characteristics to inorganic oxide nanoparticles with a focus on their biomedical applications. The role of PEG as structure directing agent in synthesis of oxides is also captured in this short review.

  7. Fundamental Mvssbauer Parameters of Hydrous Iron Sulfates

    NASA Technical Reports Server (NTRS)

    Rothstein, Y.; Dyar, M. D.; Schaefer, M. W.; Lane, M. D.; Bishop, J. L.

    2005-01-01

    Hydrous iron sulfates, which form as alteration products of sulfides, are rare on Earth. On Mars, the low temperature and pH found in the martian permafrost create ideal conditions for the formation of this group of minerals [1], which includes such phases as coquimbite (Fe2(SO4) 9H2O) and amarantite (FeSO4(OH) 3H2O). Viking, Mars Pathfinder, MER and OMEGA data [e.g., [2

  8. Integrated Spectroscopic Studies of Hydrous Sulfate Minerals

    NASA Technical Reports Server (NTRS)

    Dyar, M. D.; Lane, M. D.; Bishop, J. L.; OConnor, V.; Cloutis, E.; Hiroi, T.

    2005-01-01

    Sulfate minerals have been identified in Martian meteorites and on Mars using a suite of instruments aboard the MER rovers. These results have confirmed previous groundbased observations and orbital measurements that suggested their presence. The orbiting OMEGA instrument on Mars Express is also finding evidence for sulfate. In order to better interpret remote-sensing data, we present here the results of a coordinated visible/near infrared (VNIR) reflectance, Moussbauer (MB), and thermal emittance study of wellcharacterized hydrous sulfate minerals.

  9. Temperature-induced transformation of electrochemically formed hydrous RuO2 layers over Ru(0001) model electrodes

    NASA Astrophysics Data System (ADS)

    Krause, Philipp P. T.; Camuka, Hava; Leichtweiss, Thomas; Over, Herbert

    2016-07-01

    Hydrous RuO2 reveals excellent performance both as a supercapacitor and as a heterogeneous oxidation catalyst. Molecular understanding of these processes needs, however, a model system with preferably low structural and morphological complexity. This goal is partly accomplished here by using single crystalline Ru(0001) as a template on which hydrous RuO2 is electrochemically formed. The hydrous RuO2 layers on Ru(0001) and their temperature induced transformation under ultra high vacuum (UHV) conditions are comprehensively characterized by scanning electron microscopy and X-ray photoemission spectroscopy. The hydrous RuO2 layer grows with an intricate morphology governed by the presence of step bunching regions of the Ru(0001) surface. Upon annealing to 200 °C in UHV the hydrous RuO2 layer transforms mostly into flat metallic Ru islands and occasionally into (100) and (111) oriented RuO2 particles aligned along the high symmetry direction of Ru(0001).Hydrous RuO2 reveals excellent performance both as a supercapacitor and as a heterogeneous oxidation catalyst. Molecular understanding of these processes needs, however, a model system with preferably low structural and morphological complexity. This goal is partly accomplished here by using single crystalline Ru(0001) as a template on which hydrous RuO2 is electrochemically formed. The hydrous RuO2 layers on Ru(0001) and their temperature induced transformation under ultra high vacuum (UHV) conditions are comprehensively characterized by scanning electron microscopy and X-ray photoemission spectroscopy. The hydrous RuO2 layer grows with an intricate morphology governed by the presence of step bunching regions of the Ru(0001) surface. Upon annealing to 200 °C in UHV the hydrous RuO2 layer transforms mostly into flat metallic Ru islands and occasionally into (100) and (111) oriented RuO2 particles aligned along the high symmetry direction of Ru(0001). Electronic supplementary information (ESI) available. See DOI: 10

  10. Inorganic nitrate promotes the browning of white adipose tissue through the nitrate-nitrite-nitric oxide pathway.

    PubMed

    Roberts, Lee D; Ashmore, Tom; Kotwica, Aleksandra O; Murfitt, Steven A; Fernandez, Bernadette O; Feelisch, Martin; Murray, Andrew J; Griffin, Julian L

    2015-02-01

    Inorganic nitrate was once considered an oxidation end product of nitric oxide metabolism with little biological activity. However, recent studies have demonstrated that dietary nitrate can modulate mitochondrial function in man and is effective in reversing features of the metabolic syndrome in mice. Using a combined histological, metabolomics, and transcriptional and protein analysis approach, we mechanistically defined that nitrate not only increases the expression of thermogenic genes in brown adipose tissue but also induces the expression of brown adipocyte-specific genes and proteins in white adipose tissue, substantially increasing oxygen consumption and fatty acid β-oxidation in adipocytes. Nitrate induces these phenotypic changes through a mechanism distinct from known physiological small molecule activators of browning, the recently identified nitrate-nitrite-nitric oxide pathway. The nitrate-induced browning effect was enhanced in hypoxia, a serious comorbidity affecting white adipose tissue in obese individuals, and corrected impaired brown adipocyte-specific gene expression in white adipose tissue in a murine model of obesity. Because resulting beige/brite cells exhibit antiobesity and antidiabetic effects, nitrate may be an effective means of inducing the browning response in adipose tissue to treat the metabolic syndrome.

  11. The metabolism of inorganic arsenic oxides, gallium arsenide, and arsine: a toxicochemical review.

    PubMed

    Carter, Dean E; Aposhian, H Vasken; Gandolfi, A Jay

    2003-12-15

    The aim of this review is to compare the metabolism, chemistry, and biological effects to determine if either of the industrial arsenicals (arsine and gallium arsenide) act like the environmental arsenic oxides (arsenite and arsenate). The metabolism of the arsenic oxides has been extensively investigated in the past 4 years and the differences between the arsenic metabolites in the oxidation states +III versus +V and with one or two methyl groups added have shown increased importance. The arsenic oxide metabolism has been compared with arsine (oxidation state -III) and arsenide (oxidation state between 0 to -III). The different metabolites appear to have different strengths of reaction for binding arsenic (III) to thiol groups, their oxidation-reduction reactions and their forming an arsenic-carbon bond. It is unclear if the differences in parameters such as the presence or absence of methyl metabolites, the rates of AsV reduction compared to the rates of AsIII oxidation, or the competition of phosphate and arsenate for cellular uptake are large enough to change biological effects. The arsine rate of decomposition, products of metabolism, target organ of toxic action, and protein binding appeared to support an oxidized arsenic metabolite. This arsine metabolite was very different from anything made by the arsenic oxides. The gallium arsenide had a lower solubility than any other arsenic compound and it had a disproportionate intensity of lung damage to suggest that the GaAs had a site of contact interaction and that oxidation reactions were important in its toxicity. The urinary metabolites after GaAs exposure were the same as excreted by arsenic oxides but the chemical compounds responsible for the toxic effects of GaAs are different from the arsenic oxides. The review concludes that there is insufficient evidence to equate the different arsenic compounds. There are several differences in the toxicity of the arsenic compounds that will require substantial

  12. The metabolism of inorganic arsenic oxides, gallium arsenide, and arsine: a toxicochemical review.

    PubMed

    Carter, Dean E; Aposhian, H Vasken; Gandolfi, A Jay

    2003-12-15

    The aim of this review is to compare the metabolism, chemistry, and biological effects to determine if either of the industrial arsenicals (arsine and gallium arsenide) act like the environmental arsenic oxides (arsenite and arsenate). The metabolism of the arsenic oxides has been extensively investigated in the past 4 years and the differences between the arsenic metabolites in the oxidation states +III versus +V and with one or two methyl groups added have shown increased importance. The arsenic oxide metabolism has been compared with arsine (oxidation state -III) and arsenide (oxidation state between 0 to -III). The different metabolites appear to have different strengths of reaction for binding arsenic (III) to thiol groups, their oxidation-reduction reactions and their forming an arsenic-carbon bond. It is unclear if the differences in parameters such as the presence or absence of methyl metabolites, the rates of AsV reduction compared to the rates of AsIII oxidation, or the competition of phosphate and arsenate for cellular uptake are large enough to change biological effects. The arsine rate of decomposition, products of metabolism, target organ of toxic action, and protein binding appeared to support an oxidized arsenic metabolite. This arsine metabolite was very different from anything made by the arsenic oxides. The gallium arsenide had a lower solubility than any other arsenic compound and it had a disproportionate intensity of lung damage to suggest that the GaAs had a site of contact interaction and that oxidation reactions were important in its toxicity. The urinary metabolites after GaAs exposure were the same as excreted by arsenic oxides but the chemical compounds responsible for the toxic effects of GaAs are different from the arsenic oxides. The review concludes that there is insufficient evidence to equate the different arsenic compounds. There are several differences in the toxicity of the arsenic compounds that will require substantial

  13. Organic-inorganic random copolymers from methacrylate-terminated poly(ethylene oxide) with 3-methacryloxypropylheptaphenyl polyhedral oligomeric silsesquioxane: synthesis via RAFT polymerization and self-assembly behavior.

    PubMed

    Wei, Kun; Li, Lei; Zheng, Sixun; Wang, Ge; Liang, Qi

    2014-01-14

    In this contribution, we report the synthesis of organic-inorganic random polymers from methacrylate-terminated poly(ethylene oxide) (MAPEO) (Mn = 950) and 3-methacryloxypropylheptaphenyl polyhedral oligomeric silsesquioxane (MAPOSS) macromers via reversible addition-fragmentation chain transfer (RAFT) polymerization with 4-cyano-4-(thiobenzoylthio) valeric acid (CTBTVA) as the chain transfer agent. The organic-inorganic random copolymers were characterized by means of (1)H NMR spectroscopy, gel permeation chromatography (GPC) and differential scanning calorimetry (DSC). The results of GPC indicate that the polymerizations were carried out in a controlled fashion. Transmission electron microscopy (TEM) showed that the organic-inorganic random copolymers in bulk were microphase-separated and the POSS microdomains were formed via POSS-POSS interactions. In aqueous solutions the organic-inorganic random copolymers were capable of self-assembling into spherical nanoobjects as evidenced by transmission electron microscopy (TEM) and dynamic laser scattering (DLS). The self-assembly behavior of the organic-inorganic random copolymers was also found to occur in the mixtures with the precursors of epoxy. The nanostructures were further fixed via subsequent curing reaction and thus the organic-inorganic nanocomposites were obtained. The formation of nanophases in epoxy thermosets was confirmed by transmission electron microscopy (TEM) and dynamic mechanical thermal analysis (DMTA). The organic-inorganic nanocomposites displayed the enhanced surface hydrophobicity as evidenced by surface contact angle measurements.

  14. A new sensitive organic/inorganic hybrid material based on titanium oxide for the potentiometric detection of iron(III).

    PubMed

    Becuwe, M; Rouge, P; Gervais, C; Courty, M; Dassonville-Klimpt, A; Sonnet, P; Baudrin, E

    2012-12-15

    The formation of a new hybrid material based on titanium dioxide as inorganic support and containing an iron organochelator (ICL670) is described. An organophosphorous coupling agent was used to graft the organic molecule on the oxide surface. The attachment of the organic substrate was well-confirmed by FTIR (DRIFT), solid-state (31)P and (13)C CPMAS NMR, thermal analysis and the integrity of the structural and morphological parameters were verified using XRD and TEM analyses. The interaction between the material and dissolved iron(III) was also investigated through potentiometric measurements and demonstrated the interest of this new non-siliceous based hybrid material. The obtained linear evolution of the open circuit potential from 10(-2) to 10(-6) mol L(-1) can be used for the analytical detection of iron(III).

  15. Frontier Orbital Engineering of Metal-Organic Frameworks with Extended Inorganic Connectivity: Porous Alkaline-Earth Oxides.

    PubMed

    Hendon, Christopher H; Walsh, Aron; Dincă, Mircea

    2016-08-01

    The development of conductive metal-organic frameworks is challenging owing to poor electronic communication between metal clusters and the organic ligands that bridge them. One route to overcoming this bottleneck is to extend the inorganic dimensionality, while using the organic components to provide chemical functionality. Using density functional theory methods, we demonstrate how the properties of the alkaline-earth oxides SrO and BaO are transformed upon formation of porous solids with organic oxygen sources (acetate and trifluoroacetate). The electron affinity is significantly enhanced in the hybrid materials, while the ionization potential can be tuned over a large range with the polarity of the organic moiety. Furthermore, because of their high-vacuum fraction, these materials have dielectric properties suitable for low-κ applications.

  16. Versatile Oxidation Methods for Organic and Inorganic Substrates Catalyzed by Platinum-Group Metals on Carbons.

    PubMed

    Sawama, Yoshinari; Asai, Shota; Monguchi, Yasunari; Sajiki, Hironao

    2016-02-01

    Platinum-group metals on activated carbon catalysts, represented by Pd/C, Ru/C, Rh/C, etc., are widely utilized to accomplish green and sustainable organic reactions due to their favorable features, such as easy handling, recoverability, and reusability. The efficient oxidation methods of various organic compounds using heterogeneous platinum-group metals on carbons with or without added oxidants are summarized in this Personal Account. The oxidation of internal alkynes into diketones was effectively catalyzed by Pd/C in the presence of dimethyl sulfoxide and molecular oxygen or pyridine N-oxide. The Pd/C-catalyzed mild combustion of gaseous hydrogen with molecular oxygen provided hydrogen peroxide, which could be directly utilized for the oxidation of sulfide derivatives into sulfoxides. Furthermore, the Ru/C-catalyzed aerobic oxidation of primary and secondary alcohols gave the corresponding aldehydes and ketones, respectively. On the other hand, the dehydrogenative oxidation of secondary alcohols into ketones was achieved using Rh/C in water, and primary alcohols were effectively dehydrogenated by Pd/C in water under mildly reduced pressure to produce carboxylic acids. PMID:26666634

  17. Graphene-Inorganic Hybrids with Cobalt Oxide Polymorphs for Electrochemical Energy Systems and Electrocatalysis: Synthesis, Processing and Properties

    NASA Astrophysics Data System (ADS)

    Gupta, Sanju; Carrizosa, Sara B.

    2015-11-01

    We report on the synthesis and physical property characterization of graphene-inorganic `hybrid' nanomaterials coupled with nano-/microscale transition metal oxide polymorphs namely, cobalt oxides, i.e. CoO [Co(II)] and Co3O4 [Co(II, III)]), for alternative energy storage and conversion devices. Their demand is owed to higher specific capacitance, wide operational potential window, stability through charge-discharge cycling, environmentally benignity, easily processability, reproducibility and manufacturability. To accomplish this, we strategically designed these hybrids by direct anchoring or physisorption of CoO and CO3O4 on two different variants of graphene: graphene oxide which is semiconducting, and its reduced form showing conducting behavior via mixing dispersions of the constituents under mild ultrasonication and drop-cast (or spray-cast) resulting in different combinations. This facile approach affords strong chemical/physical attachment and is expected to have coupling between the pseudocapacitive transition metal oxides and supercapacitive graphene showing enhanced surface activity/reactivity and reasonable areal density of tailored interfaces. We used a range of complementary tools to establish microscopic structure-property-function correlations including scanning electron microscopy combined with energy dispersive x-ray spectroscopy, atomic force microscopy, x-ray diffraction, transmission electron microscopy in conjunction with selected-area electron diffraction, and resonance Raman spectroscopy combined with elemental Raman mapping. They reveal surface morphology, local (lattice dynamical) and average structure and surface charge transfer/doping due to physically (or chemically) adsorbed cobalt oxide and highlight the surface structure and interfaces. This lays the groundwork to further investigate the electrochemical properties as high-performance supercapacitor cathodes, rechargeable secondary battery anodes and electrocatalytical platforms.

  18. Nitrous oxide emissions after sewage sludge and inorganic N-fertilization of a willow bio-energy plantation

    NASA Astrophysics Data System (ADS)

    Klemedtsson, Leif; Hedenrud, Anna; Rychlik, Sophie; Weslien, Per; Kasimir Klemedtsson, Åsa; Achberger, Christine; Lindroth, Anders

    2014-05-01

    The use of sewage sludge as fertilizer after harvest or inorganic N-fertilization of bio-energy plantations can give rise to high emissions of the greenhouse gas nitrous oxide (N2O). Plantations of e.g. willow (Salix) are today grown and used for bioenergy purposes. They could serve as carbon and nitrogen sinks, lowering greenhouse gas emissions and helping to mitigate a change in climate. However, since N2O is such a powerful greenhouse gas it can have a large impact on the total emission of greenhouse gases from a bio-energy plantation. The magnitude of N2O emissions after fertilization is therefore important to investigate. This study concerns N2O emissions from a conventionally grown bio-energy plantation of Salix. The aim of the study was to investigate the use of sewage sludge after harvest as well as inorganic N-fertilization in a growing plantation, and its effect on emissions of N2O from the soil ecosystem. The field site is a Salix plantation in south-western Sweden, a representative site in management practices and abiotic conditions. The site was divided into two areas, a larger field and smaller plots. The field was applied with sewage sludge after harvest 2013. Emissions of N2O were measured using the micrometeorological Eddy covariance technique, with a Quantum Cascade laser (Aerodyne). The fluxes of CO2 and H2O were measured using a LI-7200(Li-cor) instrument. The flux was calculated using the EddyPro software. On the plots, N2O emissions from inorganic N-fertilization (2013) were monitored using automatic chambers (height 1.05 m, volume 0.2625 m3) and a trace gas analyzer (TGA100, Campbell Scientific, USA) during approximately one (1) year. The N2O emissions from the plots (inorganic fertilizer) and field (sewage sludge) were compared with non-fertilized plots (controls) using the automatic chambers for both comparisons. The N2O emissions from the control plot for the inorganic fertilizer had an emission over the growing season that was 0.33 kg N2O

  19. Study of the Photo-oxidation and Photolysis of Unsaturated and Cross-linked Polyesters (UP) in the Presence of Photoactive or not Inorganic Fillers

    NASA Astrophysics Data System (ADS)

    Khalil, Zahi; Koubaissy, Bachar; Akil, Mariam

    Disturbances of the photochemical evolution involved in the photolysis and in the photo-oxidation at long wavelengths (ë?300 nm) of poly(propylene glycol-maleatophtalate cross-linked by the styrene (UP),caused by the addition of photo-active pigment such as zinc sulphide or black iron oxides,and no photoactive inorganic fillers such as calcium carbonate have been analysed by means of FTIR and U.V. spectrophotometry. The photo-oxidation observed by FTIR of the polymer UP in the presence of inorganic fillers leads to the same photoproducts such as ones of the photo-oxidation of the virgin polymer, but the oxidation rate is greatly affected by the nature and the percentage of the inorganic filler. Zinc sulfide and black iron are incorporated in the film of polymers, the absorption spectra of ZnS reveals that this pigment is not as absorbent as titanium oxide in a more limited field. On the other hand, with a very low inner filter effect, black iron oxides promote the formation of absorbing photoproducts. The addition of Calcium carbonate non- absorbing filler to the UP, causes a slight decrease in the evolution of the I.R

  20. Improved oxidation resistance of organic/inorganic composite atomic layer deposition coated cellulose nanocrystal aerogels

    SciTech Connect

    Smith, Sean W.; Matthews, David J.; Conley, John F.; Buesch, Christian; Simonsen, John

    2014-07-01

    Cellulose nanocrystal (CNC) aerogels are coated with thin conformal layers of Al{sub 2}O{sub 3} using atomic layer deposition to form hybrid organic/inorganic nanocomposites. Electron probe microanalysis and scanning electron microscopy analysis indicated the Al{sub 2}O{sub 3} penetrated more than 1500 μm into the aerogel for extended precursor pulse and exposure/purge times. The measured profile of coated fiber radius versus depth from the aerogel surface agrees well with simulations of precursor penetration depth in modeled aerogel structures. Thermogravimetric analysis shows that Al{sub 2}O{sub 3} coated CNC aerogel nanocomposites do not show significant thermal degradation below 295 °C as compared with 175 °C for uncoated CNC aerogels, an improvement of over 100 °C.

  1. Inorganic oxide core, polymer shell nanocomposite as a high K gate dielectric for flexible electronics applications.

    PubMed

    Maliakal, Ashok; Katz, Howard; Cotts, Pat M; Subramoney, Shekhar; Mirau, Peter

    2005-10-26

    Organic/inorganic core shell nanoparticles have been synthesized using high K TiO(2) as the core nanoparticle, and polystyrene as the shell. This material is easy to process and forms transparent continuous thin films, which exhibit a dielectric constant enhancement of over 3 times that of bulk polystyrene. This new dielectric material has been incorporated into capacitors and thin film transistors (TFTs). Mobilities approaching 0.2 cm(2)/V.s have been measured for pentacene TFTs incorporating the new TiO(2) polystyrene nanostructured gate dielectric, indicating good surface properties for pentacene film growth. This novel strategy for generating high K flexible gate dielectrics will be of value in improving organic and flexible electronic device performance.

  2. Heat Capacity of Hydrous Silicate Melts

    NASA Astrophysics Data System (ADS)

    Robert, G.; Whittington, A. G.; Stechern, A.; Behrens, H.

    2015-12-01

    We determined the heat capacities of four series of glasses and liquids of basaltic and basaltic andesite compositions including two natural remelts from Fuego volcano, Guatemala, and two Fe-free analogs. The samples are low-alkali, Ca- and Mg-rich aluminosilicates with non-bridging oxygen to tetrahedrally-coordinated cation ratios (NBO/T) ranging between 0.33 and 0.67. Differential scanning calorimetry measurements were performed at atmospheric pressure between room temperature and ≈100 K above the glass transition for hydrous samples and up to ≈1800 K for dry samples. The water contents investigated range up to 5.34 wt.% (16.4 mol%). Water does not measurably affect the heat capacity of glasses (T hydrous samples also occurs below the Dulong-Petit limit of 3R/g atom. We see little change in liquid heat capacity with increasing water content; hydrous liquid heat capacities are within 3-6% of the dry liquid, at low temperatures just above the glass transition. However, dry liquids show a decrease in heat capacity with increasing temperature above the glass transition, from supercooled to superliquidus temperatures. Liquid heat capacity values just above the glass transition range between 95-100 J/mol K, whereas liquid heat capacity values at superliquidus temperatures are between 85-91 J/mol K. Comparison with other studies of the heat capacity of hydrous glasses and liquids shows that the liquid heat capacity of strongly depolymerized samples (NBO/T ≥ 0.8) increases with increasing water content, whereas depolymerized samples (0.4 ≤ NBO/T ≤ 0.8) or polymerized samples (NBO/T ≤ 0.4) generally show little change or a moderate decrease in liquid heat capacity with increasing water content.

  3. Directed synthesis of bio-inorganic vanadium oxide composites using genetically modified filamentous phage

    NASA Astrophysics Data System (ADS)

    Mueller, Michael; Baik, Seungyun; Jeon, Hojeong; Kim, Yuchan; Kim, Jungtae; Kim, Young Jun

    2015-05-01

    The growth of crystalline vanadium oxide using a filamentous bacteriophage template was investigated using sequential incubation in a V2O5 precursor. Using the genetic modification of the bacteriophage, we displayed two cysteines that constrained the RSTB-1 peptide on the major coat protein P8, resulting in vanadium oxide crystallization. The phage-driven vanadium oxide crystals with different topologies, microstructures, photodegradation and vanadium oxide composites were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), quartz microbalance and dissipation (QCM-D) and X-ray photoelectron spectroscopy (XPS). Non-specific electrostatic attraction between a wild-type phage (wt-phage) and vanadium cations in the V2O5 precursor caused phage agglomeration and fiber formation along the length of the viral scaffold. As a result, the addition of recombinant phage (re-phage) in V2O5 precursors formed heterogeneous structures, which led to efficient condensation of vanadium oxide crystal formation in lines, shown by QCM-D analysis. Furthermore, re-phage/VxOx composites showed significantly enhanced photodegradation activities compared with the synthesized wt-phage-V2O5 composite under illumination. This study demonstrates that peptide-mediated vanadium oxide mineralization is governed by a complicated interplay of peptide sequence, local structure, kinetics and the presence of a mineralizing aid, such as the two cysteine-constrained peptides on the phage surface, and has potential for use in nanotechnology applications.

  4. Komatiites reveal a hydrous Archaean deep-mantle reservoir.

    PubMed

    Sobolev, Alexander V; Asafov, Evgeny V; Gurenko, Andrey A; Arndt, Nicholas T; Batanova, Valentina G; Portnyagin, Maxim V; Garbe-Schönberg, Dieter; Krasheninnikov, Stepan P

    2016-03-31

    Archaean komatiites (ultramafic lavas) result from melting under extreme conditions of the Earth's mantle. Their chemical compositions evoke very high eruption temperatures, up to 1,600 degrees Celsius, which suggests even higher temperatures in their mantle source. This message is clouded, however, by uncertainty about the water content in komatiite magmas. One school of thought holds that komatiites were essentially dry and originated in mantle plumes while another argues that these magmas contained several per cent water, which drastically reduced their eruption temperature and links them to subduction processes. Here we report measurements of the content of water and other volatile components, and of major and trace elements in melt inclusions in exceptionally magnesian olivine (up to 94.5 mole per cent forsterite). This information provides direct estimates of the composition and crystallization temperature of the parental melts of Archaean komatiites. We show that the parental melt for 2.7-billion-year-old komatiites from the Abitibi greenstone belt in Canada contained 30 per cent magnesium oxide and 0.6 per cent water by weight, and was depleted in highly incompatible elements. This melt began to crystallize at around 1,530 degrees Celsius at shallow depth and under reducing conditions, and it evolved via fractional crystallization of olivine, accompanied by minor crustal assimilation. As its major- and trace-element composition and low oxygen fugacities are inconsistent with a subduction setting, we propose that its high H2O/Ce ratio (over 6,000) resulted from entrainment into the komatiite source of hydrous material from the mantle transition zone. These results confirm a plume origin for komatiites and high Archaean mantle temperatures, and evoke a hydrous reservoir in the deep mantle early in Earth's history. PMID:27029278

  5. Komatiites reveal a hydrous Archaean deep-mantle reservoir

    NASA Astrophysics Data System (ADS)

    Sobolev, Alexander V.; Asafov, Evgeny V.; Gurenko, Andrey A.; Arndt, Nicholas T.; Batanova, Valentina G.; Portnyagin, Maxim V.; Garbe-Schönberg, Dieter; Krasheninnikov, Stepan P.

    2016-03-01

    Archaean komatiites (ultramafic lavas) result from melting under extreme conditions of the Earth’s mantle. Their chemical compositions evoke very high eruption temperatures, up to 1,600 degrees Celsius, which suggests even higher temperatures in their mantle source. This message is clouded, however, by uncertainty about the water content in komatiite magmas. One school of thought holds that komatiites were essentially dry and originated in mantle plumes while another argues that these magmas contained several per cent water, which drastically reduced their eruption temperature and links them to subduction processes. Here we report measurements of the content of water and other volatile components, and of major and trace elements in melt inclusions in exceptionally magnesian olivine (up to 94.5 mole per cent forsterite). This information provides direct estimates of the composition and crystallization temperature of the parental melts of Archaean komatiites. We show that the parental melt for 2.7-billion-year-old komatiites from the Abitibi greenstone belt in Canada contained 30 per cent magnesium oxide and 0.6 per cent water by weight, and was depleted in highly incompatible elements. This melt began to crystallize at around 1,530 degrees Celsius at shallow depth and under reducing conditions, and it evolved via fractional crystallization of olivine, accompanied by minor crustal assimilation. As its major- and trace-element composition and low oxygen fugacities are inconsistent with a subduction setting, we propose that its high H2O/Ce ratio (over 6,000) resulted from entrainment into the komatiite source of hydrous material from the mantle transition zone. These results confirm a plume origin for komatiites and high Archaean mantle temperatures, and evoke a hydrous reservoir in the deep mantle early in Earth’s history.

  6. Komatiites reveal a hydrous Archaean deep-mantle reservoir.

    PubMed

    Sobolev, Alexander V; Asafov, Evgeny V; Gurenko, Andrey A; Arndt, Nicholas T; Batanova, Valentina G; Portnyagin, Maxim V; Garbe-Schönberg, Dieter; Krasheninnikov, Stepan P

    2016-03-31

    Archaean komatiites (ultramafic lavas) result from melting under extreme conditions of the Earth's mantle. Their chemical compositions evoke very high eruption temperatures, up to 1,600 degrees Celsius, which suggests even higher temperatures in their mantle source. This message is clouded, however, by uncertainty about the water content in komatiite magmas. One school of thought holds that komatiites were essentially dry and originated in mantle plumes while another argues that these magmas contained several per cent water, which drastically reduced their eruption temperature and links them to subduction processes. Here we report measurements of the content of water and other volatile components, and of major and trace elements in melt inclusions in exceptionally magnesian olivine (up to 94.5 mole per cent forsterite). This information provides direct estimates of the composition and crystallization temperature of the parental melts of Archaean komatiites. We show that the parental melt for 2.7-billion-year-old komatiites from the Abitibi greenstone belt in Canada contained 30 per cent magnesium oxide and 0.6 per cent water by weight, and was depleted in highly incompatible elements. This melt began to crystallize at around 1,530 degrees Celsius at shallow depth and under reducing conditions, and it evolved via fractional crystallization of olivine, accompanied by minor crustal assimilation. As its major- and trace-element composition and low oxygen fugacities are inconsistent with a subduction setting, we propose that its high H2O/Ce ratio (over 6,000) resulted from entrainment into the komatiite source of hydrous material from the mantle transition zone. These results confirm a plume origin for komatiites and high Archaean mantle temperatures, and evoke a hydrous reservoir in the deep mantle early in Earth's history.

  7. Kinetics of the Heterogeneous Reaction CO + O = CO(sub 2) on Inorganic Oxide and Water Ice Surfaces: Implications for the Martian Atmosphere

    NASA Technical Reports Server (NTRS)

    Leu, Ming-Taun; Choi, Wonyong

    1997-01-01

    The heterogeneous reaction CO + O - CO(sub 2) on water ice and varios inorganic oxide surfaces has been investigated in order to evaluate the proposition that this heterogeneous reaction may contribute to the CO(sub 2) stability in the Martian atmosphere.

  8. Th and U in hydrous rhyolite melts

    NASA Astrophysics Data System (ADS)

    Xing, L.; Watson, E. B.; Ruscitto, D. M.

    2012-12-01

    We measured diffusion coefficients of thorium (Th) and uranium (U) in hydrous (up to 6 wt.% H2O) melts of Lake County Obsidian at 1 GPa and temperatures ranging from 900°C to 1200°C. Diffusion couples were assembled from pre-synthesized capsule halves with high (~500 ppm) and low (~100 ppm) concentrations of U and Th. Experiments were run for 4 to 54 hours, depending on temperature, and the resulting concentration profiles were characterized by LA-ICP/MS in the case of U and both EPMA and LA-ICP/MS in the case of Th. Th and U have almost identical diffusivities, ranging from 10-9 to 10-7 cm2/s over the temperature range examined. We observed Arrhenius behavior for both Th and U, and constrain activation energies to E ~140 and 116 kJ/mole, respectively. Measured diffusivities are insensitive to dissolved H2O contents at > 6 wt%. Modest down-temperature extrapolation to conditions relevant to the Earth's crust (700 - 850°C) give Th and U diffusivities of ~10-10 cm2/s. Our results are comparable with known values for the major structural constituents of accessory minerals that concentrate U and Th (e.g., zircon, monazite, apatite, xenotime), so the diffusive supply of U and Th to growing crystals is adequate to preclude significant disequilibrium uptake during growth. The results complement and extend previous results on Th and U diffusion in hydrous molten granite.

  9. Efficient organic-inorganic hybrid perovskites and doped metal oxide heterojunction solar cells

    NASA Astrophysics Data System (ADS)

    Fan, Xiaojuan

    Organic-Inorganic hybrid perovskite CH3NH3PbI3 has recently attracted much attention for its high efficient solar energy conversion. This semiconducting pigment with a direct bandgap of 1.55 eV has made it an interesting optical and electronic material over the whole visible solar emission spectrum. The role of hole conducting has been found in this semiconductor that allows perovskite solar cell (PSC) to be formed by CH3NH3PbI3/TiO2 heterojunctions that use TiO2 as scaffold, and carbon as a back contact. We will report a double layer metal doped TiO2/Al2O3 mesoporous scaffold covered by the p-type semiconducting pigment to form a high efficient PSC through solution method. TiO2 and Al2O3 are both large band gap semiconductors that affect conducting and recombination rate in solar cells. One improvement work is doping other metal elements in TiO2 to raise the mobility while extend the recombination time. It has suggested that optimal amounts of doped metals such as Cu, Co, Mn can suppress the reduction of Ti4 + resulting better transportation. TiO2 thin films doped with metals are subjected to the EPR analysis and the results will be correlated with measurements of electronic-optical properties.

  10. Photocatalytical removal of inorganic and organic arsenic species from aqueous solution using zinc oxide semiconductor.

    PubMed

    Rivera-Reyna, Nidia; Hinojosa-Reyes, Laura; Guzmán-Mar, Jorge Luis; Cai, Yong; O'Shea, Kevin; Hernández-Ramírez, Aracely

    2013-04-01

    The photocatalytic removal of arsenite [As(III)] and monomethylarsonic acid [MMA(V)] was investigated in the presence of UV light (350 nm) and aqueous suspensions of ZnO synthesized by the sol-gel technique. Photocatalytic removal of these potent arsenic compounds results in the effective and rapid mineralization to less toxic inorganic arsenate [As(V)]. The effect of ZnO loading and solution pH on the treatment efficiency of the UV/ZnO photocatalytic process was evaluated. The optimal conditions for the removal of 5 mg L(-1) [As(III)] and [MMA(V)] aqueous solutions were observed at catalyst loadings of 0.25 and 0.50 g L(-1) with solution pH values of 7 and 8, respectively. Under these conditions, the activity of photocatalyst sol-gel ZnO was compared with TiO2 Degussa P25 and commercial ZnO catalyst. The results demonstrate that the high adsorption capacity of ZnO synthesized by sol-gel gives enhanced removal of arsenic species from water samples, indicating that this catalyst is a promising material for treatment of arsenic contaminated groundwater. PMID:23064294

  11. Photocatalytical removal of inorganic and organic arsenic species from aqueous solution using zinc oxide semiconductor.

    PubMed

    Rivera-Reyna, Nidia; Hinojosa-Reyes, Laura; Guzmán-Mar, Jorge Luis; Cai, Yong; O'Shea, Kevin; Hernández-Ramírez, Aracely

    2013-04-01

    The photocatalytic removal of arsenite [As(III)] and monomethylarsonic acid [MMA(V)] was investigated in the presence of UV light (350 nm) and aqueous suspensions of ZnO synthesized by the sol-gel technique. Photocatalytic removal of these potent arsenic compounds results in the effective and rapid mineralization to less toxic inorganic arsenate [As(V)]. The effect of ZnO loading and solution pH on the treatment efficiency of the UV/ZnO photocatalytic process was evaluated. The optimal conditions for the removal of 5 mg L(-1) [As(III)] and [MMA(V)] aqueous solutions were observed at catalyst loadings of 0.25 and 0.50 g L(-1) with solution pH values of 7 and 8, respectively. Under these conditions, the activity of photocatalyst sol-gel ZnO was compared with TiO2 Degussa P25 and commercial ZnO catalyst. The results demonstrate that the high adsorption capacity of ZnO synthesized by sol-gel gives enhanced removal of arsenic species from water samples, indicating that this catalyst is a promising material for treatment of arsenic contaminated groundwater.

  12. Photocatalytical removal of inorganic and organic arsenic species from aqueous solution using zinc oxide semiconductor†

    PubMed Central

    Rivera-Reyna, Nidia; Hinojosa-Reyes, Laura; Guzmán-Mar, Jorge Luis; Cai, Yong; O'Shea, Kevin; Hernández-Ramírez, Aracely

    2012-01-01

    The photocatalytic removal of arsenite [As(III)] and monomethylarsonic acid [MMA(V)] was investigated in the presence of UV light (350 nm) and aqueous suspensions of ZnO synthesized by the sol–gel technique. Photocatalytic removal of these potent arsenic compounds results in the effective and rapid mineralization to less toxic inorganic arsenate [As(V)]. The effect of ZnO loading and solution pH on the treatment efficiency of the UV/ZnO photocatalytic process was evaluated. The optimal conditions for the removal of 5 mg L−1 [As(III)] and [MMA(V)] aqueous solutions were observed at catalyst loadings of 0.25 and 0.50 g L−1 with solution pH values of 7 and 8, respectively. Under these conditions, the activity of photocatalyst sol–gel ZnO was compared with TiO2 Degussa P25 and commercial ZnO catalyst. The results demonstrate that the high adsorption capacity of ZnO synthesized by sol–gel gives enhanced removal of arsenic species from water samples, indicating that this catalyst is a promising material for treatment of arsenic contaminated groundwater. PMID:23064294

  13. Synthesis of coral-like tantalum oxide films via anodization in mixed organic-inorganic electrolytes.

    PubMed

    Yu, Hongbin; Zhu, Suiyi; Yang, Xia; Wang, Xinhong; Sun, Hongwei; Huo, Mingxin

    2013-01-01

    We report a simple method to fabricate nano-porous tantalum oxide films via anodization with Ta foils as the anode at room temperature. A mixture of ethylene glycol, phosphoric acid, NH4F and H2O was used as the electrolyte where the nano-porous tantalum oxide could be synthesized by anodizing a tantalum foil for 1 h at 20 V in a two-electrode configuration. The as-prepared porous film exhibited a continuous, uniform and coral-like morphology. The diameters of pores ranged from 30 nm to 50 nm. The pores interlaced each other and the depth was about 150 nm. After calcination, the as-synthesized amorphous tantalum oxide could be crystallized to the orthorhombic crystal system. As observed in photocatalytic experiments, the coral-like tantalum oxide exhibited a higher photocatalytic activity for the degradation of phenol than that with a compact surface morphology, and the elimination rate of phenol increased by 66.7%.

  14. Synthesis of Coral-Like Tantalum Oxide Films via Anodization in Mixed Organic-Inorganic Electrolytes

    PubMed Central

    Yu, Hongbin; Zhu, Suiyi; Yang, Xia; Wang, Xinhong; Sun, Hongwei; Huo, Mingxin

    2013-01-01

    We report a simple method to fabricate nano-porous tantalum oxide films via anodization with Ta foils as the anode at room temperature. A mixture of ethylene glycol, phosphoric acid, NH4F and H2O was used as the electrolyte where the nano-porous tantalum oxide could be synthesized by anodizing a tantalum foil for 1 h at 20 V in a two–electrode configuration. The as-prepared porous film exhibited a continuous, uniform and coral-like morphology. The diameters of pores ranged from 30 nm to 50 nm. The pores interlaced each other and the depth was about 150 nm. After calcination, the as-synthesized amorphous tantalum oxide could be crystallized to the orthorhombic crystal system. As observed in photocatalytic experiments, the coral-like tantalum oxide exhibited a higher photocatalytic activity for the degradation of phenol than that with a compact surface morphology, and the elimination rate of phenol increased by 66.7%. PMID:23799106

  15. Influence of inorganic nitrogen management regime on the diversity of nitrite-oxidizing bacteria in agricultural grassland soils.

    PubMed

    Freitag, Thomas E; Chang, Lisa; Clegg, Christopher D; Prosser, James I

    2005-12-01

    To assess links between the diversity of nitrite-oxidizing bacteria (NOB) in agricultural grassland soils and inorganic N fertilizer management, NOB communities in fertilized and unfertilized soils were characterized by analysis of clone libraries and denaturing gradient gel electrophoresis (DGGE) of 16S rRNA gene fragments. Previously uncharacterized Nitrospira-like sequences were isolated from both long-term-fertilized and unfertilized soils, but DGGE migration patterns indicated the presence of additional sequence types in the fertilized soils. Detailed phylogenetic analysis of Nitrospira-like sequences suggests the existence of one newly described evolutionary group and of subclusters within previously described sublineages, potentially representing different ecotypes; the new group may represent a lineage of noncharacterized Nitrospira species. Clone libraries of Nitrobacter-like sequences generated from soils under different long-term N management regimes were dominated by sequences with high similarity to the rhizoplane isolate Nitrobacter sp. strain PJN1. However, the diversity of Nitrobacter communities did not differ significantly between the two soil types. This is the first cultivation-independent study of nitrite-oxidizing bacteria in soil demonstrating that nitrogen management practices influence the diversity of this bacterial functional group.

  16. New sol-gel synthetic route to transition and main-group metal oxide aerogels using inorganic salt precursors

    SciTech Connect

    Gash, A E; Tillotson, T M; Satcher Jr, J H; Hrubesh, L W; Simpson, R L

    2000-09-12

    We have developed a new sol-gel route to synthesize several transition and main-group metal oxide aerogels. The approach is straightforward, inexpensive, versatile, and it produces monolithic microporous materials with high surface areas. Specifically, we report the use of epoxides as gelation agents for the sol-gel synthesis of chromia aerogels and xerogels from simple Cr(III) inorganic salts. The dependence of both gel formation and its rate was studied by varying the solvent used, the Cr(III) precursor salt, the epoxide/Cr(III) ratio, as well as the type of epoxide employed. All of these variables were shown to affect the rate of gel formation and provide a convenient control of this parameter. Dried chromia aerogels were characterized by high-resolution transmission electron microscopy (HRTEM) and nitrogen adsorption/desorption analyses, results of which will be presented. Our studies have shown that rigid monolithic gels can be prepared from many different metal ions salts, provided the formal oxidation state of the metal ion is greater than or equal to +3. Conversely, when di-valent transition metal salts are used precipitated solids are the products.

  17. Inorganic greywater matrix impact on photocatalytic oxidation: does flocculation of TiO2 nanoparticles impair process efficiency?

    PubMed

    Armanious, A; Ozkan, A; Sohmen, U; Gulyas, H

    2011-01-01

    This study was conducted in order to clarify whether photocatalyst flocculation--as observed in biologically pretreated greywater--contributes to photocatalytic oxidation (PCO) efficiency impairment. Aqueous solutions of tetraethyleneglycol dimethylether spiked with different inorganic salts in concentrations as found in biologically treated greywater were investigated with respect to TiO2 flocculation and PCO mineralisation kinetics. Flocculation of the photocatalyst primarily depended on pH (which was affected by the salts) and how close pH was to the point of zero charge (PZC). Photocatalyst agglomeration was maximum at pH 5.5. With salt concentrations >7 mmol L(-1), flocculation was strong even at pH far above PZC due to electric double layer compression. PCO rate constants were not unequivocally related to flocculation. Increasing pH was observed as the clearest factor deteriorating PCO efficiency. This was interpreted to result from impaired adsorbability of negatively charged oxidation intermediates as well as from enhanced CO2 absorption with increasing pH and subsequent formation of HCO3(-) anions which are OH radical scavengers.

  18. Efficiency of photosynthetic water oxidation at ambient and depleted levels of inorganic carbon.

    PubMed

    Shevela, Dmitriy; Nöring, Birgit; Koroidov, Sergey; Shutova, Tatiana; Samuelsson, Göran; Messinger, Johannes

    2013-11-01

    Over 40 years ago, Joliot et al. (Photochem Photobiol 10:309-329, 1969) designed and employed an elegant and highly sensitive electrochemical technique capable of measuring O2 evolved by photosystem II (PSII) in response to trains of single turn-over light flashes. The measurement and analysis of flash-induced oxygen evolution patterns (FIOPs) has since proven to be a powerful method for probing the turnover efficiency of PSII. Stemler et al. (Proc Natl Acad Sci USA 71(12):4679-4683, 1974), in Govindjee's lab, were the first to study the effect of "bicarbonate" on FIOPs by adding the competitive inhibitor acetate. Here, we extend this earlier work by performing FIOPs experiments at various, strictly controlled inorganic carbon (Ci) levels without addition of any inhibitors. For this, we placed a Joliot-type bare platinum electrode inside a N2-filled glove-box (containing 10-20 ppm CO2) and reduced the Ci concentration simply by washing the samples in Ci-depleted media. FIOPs of spinach thylakoids were recorded either at 20-times reduced levels of Ci or at ambient Ci conditions (390 ppm CO2). Numerical analysis of the FIOPs within an extended Kok model reveals that under Ci-depleted conditions the miss probability is discernibly larger (by 2-3 %) than at ambient conditions, and that the addition of 5 mM HCO3 (-) to the Ci-depleted thylakoids largely restores the original miss parameter. Since a "mild" Ci-depletion procedure was employed, we discuss our data with respect to a possible function of free or weakly bound HCO3 (-) at the water-splitting side of PSII. PMID:23828399

  19. Easily processable multimodal spectral converters based on metal oxide/organic—inorganic hybrid nanocomposites

    NASA Astrophysics Data System (ADS)

    Julián-López, Beatriz; Gonell, Francisco; Lima, Patricia P.; Freitas, Vânia T.; André, Paulo S.; Carlos, Luis D.; Ferreira, Rute A. S.

    2015-10-01

    This manuscript reports the synthesis and characterization of the first organic-inorganic hybrid material exhibiting efficient multimodal spectral converting properties. The nanocomposite, made of Er3+, Yb3+ codoped zirconia nanoparticles (NPs) entrapped in a di-ureasil d-U(600) hybrid matrix, is prepared by an easy two-step sol-gel synthesis leading to homogeneous and transparent materials that can be very easily processed as monolith or film. Extensive structural characterization reveals that zirconia nanocrystals of 10-20 nm in size are efficiently dispersed into the hybrid matrix and that the local structure of the di-ureasil is not affected by the presence of the NPs. A significant enhancement in the refractive index of the di-ureasil matrix with the incorporation of the ZrO2 nanocrystals is observed. The optical study demonstrates that luminescent properties of both constituents are perfectly preserved in the final hybrid. Thus, the material displays a white-light photoluminescence from the di-ureasil component upon excitation at UV/visible radiation and also intense green and red emissions from the Er3+- and Yb3+-doped NPs after NIR excitation. The dynamics of the optical processes were also studied as a function of the lanthanide content and the thickness of the films. Our results indicate that these luminescent hybrids represent a low-cost, environmentally friendly, size-controlled, easily processed and chemically stable alternative material to be used in light harvesting devices such as luminescent solar concentrators, optical fibres and sensors. Furthermore, this synthetic approach can be extended to a wide variety of luminescent NPs entrapped in hybrid matrices, thus leading to multifunctional and versatile materials for efficient tuneable nonlinear optical nanodevices.

  20. Inorganic nitrite attenuates NADPH oxidase-derived superoxide generation in activated macrophages via a nitric oxide-dependent mechanism.

    PubMed

    Yang, Ting; Peleli, Maria; Zollbrecht, Christa; Giulietti, Alessia; Terrando, Niccolo; Lundberg, Jon O; Weitzberg, Eddie; Carlström, Mattias

    2015-06-01

    Oxidative stress contributes to the pathogenesis of many disorders, including diabetes and cardiovascular disease. Immune cells are major sources of superoxide (O2(∙-)) as part of the innate host defense system, but exaggerated and sustained O2(∙-) generation may lead to progressive inflammation and organ injuries. Previous studies have proven organ-protective effects of inorganic nitrite, a precursor of nitric oxide (NO), in conditions manifested by oxidative stress and inflammation. However, the mechanisms are still not clear. This study aimed at investigating the potential role of nitrite in modulating NADPH oxidase (NOX) activity in immune cells. Mice peritoneal macrophages or human monocytes were activated by lipopolysaccharide (LPS), with or without coincubation with nitrite. O2(∙-) and peroxynitrite (ONOO(-)) formation were detected by lucigenin-based chemiluminescence and fluorescence techniques, respectively. The intracellular NO production was measured by DAF-FM DA fluorescence. NOX isoforms and inducible NO synthase (iNOS) expression were detected by qPCR. LPS increased both O2(∙-) and ONOO(-) production in macrophages, which was significantly reduced by nitrite (10µmol/L). Mechanistically, the effects of nitrite are (1) linked to increased NO generation, (2) similar to that observed with the NO donor DETA-NONOate, and (3) can be abolished by the NO scavenger carboxy-PTIO or by the xanthine oxidase (XO) inhibitor febuxostat. Nox2 expression was increased in activated macrophages, but was not influenced by nitrite. However, nitrite attenuated LPS-induced upregulation of iNOS expression. Similar to that observed in mice macrophages, nitrite also reduced O2(∙-) generation in LPS-activated human monocytes. In conclusion, XO-mediated reduction of nitrite attenuates NOX activity in activated macrophages, which may modulate the inflammatory response. PMID:25724690

  1. Interfacial Properties of Organic Semiconductor-Inorganic Magnetic Oxide Hybrid Spintronic Systems Fabricated Using Pulsed Laser Deposition.

    PubMed

    Majumdar, Sayani; Grochowska, Katarzyna; Sawczak, Miroslaw; Śliwiński, Gerard; Huhtinen, Hannu; Dahl, Johnny; Tuominen, Marjukka; Laukkanen, Pekka; Majumdar, Himadri S

    2015-10-14

    We report fabrication of a hybrid organic semiconductor-inorganic complex oxide interface of rubrene and La0.67Sr0.33MnO3 (LSMO) for spintronic devices using pulsed laser deposition (PLD) and investigate the interface structure and chemical bonding-dependent magnetic properties. Our results demonstrate that with proper control of growth parameters, thin films of organic semiconductor rubrene can be deposited without any damage to the molecular structure. Rubrene, a widely used organic semiconductor with high charge-carrier mobility and spin diffusion length, when grown as thin films on amorphous and crystalline substrates such as SiO2-glass, indium-tin oxide (ITO), and LSMO by PLD at room temperature and a laser fluence of 0.19 J/cm2, reveals amorphous structure. The Raman spectra verify the signatures of both Ag and Bg Raman active modes of rubrene molecules. X-ray reflectivity measurements indicate a well-defined interface formation between surface-treated LSMO and rubrene, whereas X-ray photoelectron spectra indicate the signature of hybridization of the electronic states at this interface. Magnetic measurements show that the ferromagnetic property of the rubrene-LSMO interface improves by >230% compared to the pristine LSMO surface due to this proposed hybridization. Intentional disruption of the direct contact between LSMO and rubrene by insertion of a dielectric AlOx layer results in an observably decreased ferromagnetism. These experimental results demonstrate that by controlling the interface formation between organic semiconductor and half-metallic oxide thin films, it is possible to engineer the interface spin polarization properties. Results also confirm that by using PLD for consecutive growth of different layers, contamination-free interfaces can be obtained, and this finding is significant for the well-controlled and reproducible design of spin-polarized interfaces for future hybrid spintronics devices.

  2. Interfacial Properties of Organic Semiconductor-Inorganic Magnetic Oxide Hybrid Spintronic Systems Fabricated Using Pulsed Laser Deposition.

    PubMed

    Majumdar, Sayani; Grochowska, Katarzyna; Sawczak, Miroslaw; Śliwiński, Gerard; Huhtinen, Hannu; Dahl, Johnny; Tuominen, Marjukka; Laukkanen, Pekka; Majumdar, Himadri S

    2015-10-14

    We report fabrication of a hybrid organic semiconductor-inorganic complex oxide interface of rubrene and La0.67Sr0.33MnO3 (LSMO) for spintronic devices using pulsed laser deposition (PLD) and investigate the interface structure and chemical bonding-dependent magnetic properties. Our results demonstrate that with proper control of growth parameters, thin films of organic semiconductor rubrene can be deposited without any damage to the molecular structure. Rubrene, a widely used organic semiconductor with high charge-carrier mobility and spin diffusion length, when grown as thin films on amorphous and crystalline substrates such as SiO2-glass, indium-tin oxide (ITO), and LSMO by PLD at room temperature and a laser fluence of 0.19 J/cm2, reveals amorphous structure. The Raman spectra verify the signatures of both Ag and Bg Raman active modes of rubrene molecules. X-ray reflectivity measurements indicate a well-defined interface formation between surface-treated LSMO and rubrene, whereas X-ray photoelectron spectra indicate the signature of hybridization of the electronic states at this interface. Magnetic measurements show that the ferromagnetic property of the rubrene-LSMO interface improves by >230% compared to the pristine LSMO surface due to this proposed hybridization. Intentional disruption of the direct contact between LSMO and rubrene by insertion of a dielectric AlOx layer results in an observably decreased ferromagnetism. These experimental results demonstrate that by controlling the interface formation between organic semiconductor and half-metallic oxide thin films, it is possible to engineer the interface spin polarization properties. Results also confirm that by using PLD for consecutive growth of different layers, contamination-free interfaces can be obtained, and this finding is significant for the well-controlled and reproducible design of spin-polarized interfaces for future hybrid spintronics devices. PMID:26402298

  3. Metallothionein blocks oxidative DNA damage induced by acute inorganic arsenic exposure

    SciTech Connect

    Qu, Wei Waalkes, Michael P.

    2015-02-01

    We studied how protein metallothionein (MT) impacts arsenic-induced oxidative DNA damage (ODD) using cells that poorly express MT (MT-I/II double knockout embryonic cells; called MT-null cells) and wild-type (WT) MT competent cells. Arsenic (as NaAsO{sub 2}) was less cytolethal over 24 h in WT cells (LC{sub 50} = 11.0 ± 1.3 μM; mean ± SEM) than in MT-null cells (LC{sub 50} = 5.6 ± 1.2 μM). ODD was measured by the immuno-spin trapping method. Arsenic (1 or 5 μM; 24 h) induced much less ODD in WT cells (121% and 141% of control, respectively) than in MT-null cells (202% and 260%). In WT cells arsenic caused concentration-dependent increases in MT expression (transcript and protein), and in the metal-responsive transcription factor-1 (MTF-1), which is required to induce the MT gene. In contrast, basal MT levels were not detectable in MT-null cells and unaltered by arsenic exposure. Transfection of MT-I gene into the MT-null cells markedly reduced arsenic-induced ODD levels. The transport genes, Abcc1 and Abcc2 were increased by arsenic in WT cells but either showed no or very limited increases in MT-null cells. Arsenic caused increases in oxidant stress defense genes HO-1 and GSTα2 in both WT and MT-null cells, but to much higher levels in WT cells. WT cells appear more adept at activating metal transport systems and oxidant response genes, although the role of MT in these responses is unclear. Overall, MT protects against arsenic-induced ODD in MT competent cells by potential sequestration of scavenging oxidant radicals and/or arsenic. - Highlights: • Metallothionein blocks arsenic toxicity. • Metallothionein reduces arsenic-induced DNA damage. • Metallothionein may bind arsenic or radicals produced by arsenic.

  4. Inorganic proton conducting electrolyte coupled oxide-based dendritic transistors for synaptic electronics

    NASA Astrophysics Data System (ADS)

    Wan, Chang Jin; Zhu, Li Qiang; Zhou, Ju Mei; Shi, Yi; Wan, Qing

    2014-04-01

    Ionic/electronic hybrid devices with synaptic functions are considered to be the essential building blocks for neuromorphic systems and brain-inspired computing. Here, artificial synapses based on indium-zinc-oxide (IZO) transistors gated by nanogranular SiO2 proton-conducting electrolyte films are fabricated on glass substrates. Spike-timing dependent plasticity and paired-pulse facilitation are successfully mimicked in an individual bottom-gate transistor. Most importantly, dynamic logic and dendritic integration established by spatiotemporally correlated spikes are also mimicked in dendritic transistors with two in-plane gates as the presynaptic input terminals.Ionic/electronic hybrid devices with synaptic functions are considered to be the essential building blocks for neuromorphic systems and brain-inspired computing. Here, artificial synapses based on indium-zinc-oxide (IZO) transistors gated by nanogranular SiO2 proton-conducting electrolyte films are fabricated on glass substrates. Spike-timing dependent plasticity and paired-pulse facilitation are successfully mimicked in an individual bottom-gate transistor. Most importantly, dynamic logic and dendritic integration established by spatiotemporally correlated spikes are also mimicked in dendritic transistors with two in-plane gates as the presynaptic input terminals. Electronic supplementary information (ESI) available: The structures and transfer characteristics of the IZO junctionless transistor working in bottom-gate mode and in-plane gate mode. See DOI: 10.1039/c3nr05882d

  5. Flagellar filament bio-templated inorganic oxide materials - towards an efficient lithium battery anode.

    PubMed

    Beznosov, Sergei N; Veluri, Pavan S; Pyatibratov, Mikhail G; Chatterjee, Abhijit; MacFarlane, Douglas R; Fedorov, Oleg V; Mitra, Sagar

    2015-01-13

    Designing a new generation of energy-intensive and sustainable electrode materials for batteries to power a variety of applications is an imperative task. The use of biomaterials as a nanosized structural template for these materials has the potential to produce hitherto unachievable structures. In this report, we have used genetically modified flagellar filaments of the extremely halophilic archaea species Halobacterium salinarum to synthesize nanostructured iron oxide composites for use as a lithium-ion battery anode. The electrode demonstrated a superior electrochemical performance compared to existing literature results, with good capacity retention of 1032 mAh g(-1) after 50 cycles and with high rate capability, delivering 770 mAh g(-1) at 5 A g(-1) (~5 C) discharge rate. This unique flagellar filament based template has the potential to provide access to other highly structured advanced energy materials in the future.

  6. Oxide Semiconductor-Based Flexible Organic/Inorganic Hybrid Thin-Film Transistors Fabricated on Polydimethylsiloxane Elastomer.

    PubMed

    Jung, Soon-Won; Choi, Jeong-Seon; Park, Jung Ho; Koo, Jae Bon; Park, Chan Woo; Na, Bock Soon; Oh, Ji-Young; Lim, Sang Chul; Lee, Sang Seok; Chu, Hye Yong

    2016-03-01

    We demonstrate flexible organic/inorganic hybrid thin-film transistors (TFTs) on a polydimethysilox- ane (PDMS) elastomer substrate. The active channel and gate insulator of the hybrid TFT are composed of In-Ga-Zn-O (IGZO) and blends of poly(vinylidene fluoride-trifluoroethylene) [P(VDF- TrFE)] with poly(methyl methacrylate) (PMMA), respectively. It has been confirmed that the fabri- cated TFT display excellent characteristics: the recorded field-effect mobility, sub-threshold voltage swing, and I(on)/I(off) ratio were approximately 0.35 cm2 V(-1) s(-1), 1.5 V/decade, and 10(4), respectively. These characteristics did not experience any degradation at a bending radius of 15 mm. These results correspond to the first demonstration of a hybrid-type TFT using an organic gate insulator/oxide semiconducting active channel structure fabricated on PDMS elastomer, and demonstrate the feasibility of a promising device in a flexible electronic system.

  7. Catalysis of peptide formation by inorganic oxides: high efficiency of alumina under mild conditions on the Earth-like planets.

    PubMed

    Basiuk, V A; Sainz-Rojas, J

    2001-01-01

    Amino acid condensation catalyzed by inorganic oxides is a widely recognized way for prebiotic peptide formation. Silica and alumina are widely distributed in the Earth-like planets' crust as minerals of different complexity, and thus are attractive model catalysts for the studies of abiotic peptide synthesis. Experiments performed in other laboratories have shown that this process can be efficient at > 80 degrees C, which is not easy to find on the planetary surface in combination with sufficient concentrations of amino acids and necessary catalysts. In the present work we tested catalytic activity of three forms of alumina (which proved to be an efficient catalyst for this process) in the intermolecular condensation of L-alanine. We expanded the temperature interval down to 55 degrees C and used the simplest permanent heating procedure, without employing fluctuating drying/wetting conditions. The most important finding is that even under the lowest temperature considered (i.e. 55 degrees C), short peptide formation can be detected already after 10-30 days of heating. This fact implies that the abiotic peptide formation might occur in a wide variety of planetary environments, without need for high temperatures, given the presence of amino acid building blocks and alumina-containing minerals.

  8. Oxide Semiconductor-Based Flexible Organic/Inorganic Hybrid Thin-Film Transistors Fabricated on Polydimethylsiloxane Elastomer.

    PubMed

    Jung, Soon-Won; Choi, Jeong-Seon; Park, Jung Ho; Koo, Jae Bon; Park, Chan Woo; Na, Bock Soon; Oh, Ji-Young; Lim, Sang Chul; Lee, Sang Seok; Chu, Hye Yong

    2016-03-01

    We demonstrate flexible organic/inorganic hybrid thin-film transistors (TFTs) on a polydimethysilox- ane (PDMS) elastomer substrate. The active channel and gate insulator of the hybrid TFT are composed of In-Ga-Zn-O (IGZO) and blends of poly(vinylidene fluoride-trifluoroethylene) [P(VDF- TrFE)] with poly(methyl methacrylate) (PMMA), respectively. It has been confirmed that the fabri- cated TFT display excellent characteristics: the recorded field-effect mobility, sub-threshold voltage swing, and I(on)/I(off) ratio were approximately 0.35 cm2 V(-1) s(-1), 1.5 V/decade, and 10(4), respectively. These characteristics did not experience any degradation at a bending radius of 15 mm. These results correspond to the first demonstration of a hybrid-type TFT using an organic gate insulator/oxide semiconducting active channel structure fabricated on PDMS elastomer, and demonstrate the feasibility of a promising device in a flexible electronic system. PMID:27455702

  9. Synthesis of hybrid inorganic/organic nitric oxide-releasing silica nanoparticles for biomedical applications

    NASA Astrophysics Data System (ADS)

    Carpenter, Alexis Wells

    Nitric oxide (NO) is an endogenously produced free radical involved in a number of physiological processes. Thus, much research has focused on developing scaffolds that store and deliver exogenous NO. Herein, the synthesis of N-diazeniumdiolate-modified silica nanoparticles of various physical and chemical properties for biomedical applications is presented. To further develop NO-releasing silica particles for antimicrobial applications, a reverse microemulsion synthesis was designed to achieve nanoparticles of distinct sizes and similar NO release characteristics. Decreasing scaffold size resulted in improved bactericidal activity against Pseudomonas aeruginosa. Confocal microscopy revealed that the improved efficacy resulted from faster particle-bacterium association kinetics. To broaden the therapeutic potential of NO-releasing silica particles, strategies to tune NO release characteristics were evaluated. Initially, surface hydrophobicity and NO release kinetics were tuned by grafting hydrocarbon- and fluorocarbon-based silanes onto the surface of N-diazeniumdiolate-modified particles. The addition of fluorocarbons resulted in a 10x increase in the NO release half-life. The addition of short-chained hydrocarbons to the particle surface increased their stability in hydrophobic electrospun polyurethanes. Although NO release kinetics were longer than that of unmodified particles, durations were still limited to <7 days. An alternative strategy for increasing NO release duration involved directly stabilizing the N-diazeniumdiolate using O2-protecting groups. O2-Methoxymethyl 1-(4-(3-(trimethoxysilyl)propyl))piperazin-1-yl)diazen-1-ium-1,2-diolate (MOM-Pip/NO) was grafted onto mesoporous silica nanoparticles to yield scaffolds with an NO payload of 2.5 μmol NO/mg and an NO release half-life of 23 d. Doping the MOM-Pip/NO-modified particles into resin composites yielded antibacterial NO-releasing dental restorative materials. A 3-log reduction in viable adhered

  10. [Relationship between Arsenic (+3 Oxidation State) Methyltransferase Genetic Polymorphisms and Methylation Capacity of Inorganic Arsenic].

    PubMed

    Agusa, Tetsuro; Kunito, Takashi; Minh Tue, Nguyen; Thi Mai Lan, Vi; Binh Minh, Tu; Thi Kim Trang, Pham; Fujihara, Junko; Takeshita, Haruo; Takahashi, Shin; Hung Viet, Pham; Tanabe, Shinsuke; Iwata, Hisato

    2015-01-01

    Arsenic metabolism affects the susceptibility of humans to arsenic toxicity; therefore, clarification of the factors associated with individual variations in arsenic metabolism is an important task. Genetic polymorphisms such as single nucleotide polymorphisms (SNPs) in arsenic (+3 oxidation state) methyltransferase (AS3MT), which can methylate arsenic compounds using S-adenosyl-l-methionine (AdoMet), have been reported to modify arsenic methylation. In this review, we summarize studies conducted by us in Vietnam and by others on the association of AS3MT genetic polymorphisms with arsenic metabolism as well as human health effects. Most of the SNPs in AS3MT showed inconsistent results in terms of genotype-dependent differences in arsenic metabolism among the studies. However, AS3MT 12390 (rs3740393) and 14458 (rs11191439) were consistently related to arsenic methylation regardless of the study population: AS3MT 12390 (rs3740393) affected the second step of methylation of arsenic, whereas 14458 (rs11191439) affected the first methylation step.

  11. [Relationship between Arsenic (+3 Oxidation State) Methyltransferase Genetic Polymorphisms and Methylation Capacity of Inorganic Arsenic].

    PubMed

    Agusa, Tetsuro; Kunito, Takashi; Minh Tue, Nguyen; Thi Mai Lan, Vi; Binh Minh, Tu; Thi Kim Trang, Pham; Fujihara, Junko; Takeshita, Haruo; Takahashi, Shin; Hung Viet, Pham; Tanabe, Shinsuke; Iwata, Hisato

    2015-01-01

    Arsenic metabolism affects the susceptibility of humans to arsenic toxicity; therefore, clarification of the factors associated with individual variations in arsenic metabolism is an important task. Genetic polymorphisms such as single nucleotide polymorphisms (SNPs) in arsenic (+3 oxidation state) methyltransferase (AS3MT), which can methylate arsenic compounds using S-adenosyl-l-methionine (AdoMet), have been reported to modify arsenic methylation. In this review, we summarize studies conducted by us in Vietnam and by others on the association of AS3MT genetic polymorphisms with arsenic metabolism as well as human health effects. Most of the SNPs in AS3MT showed inconsistent results in terms of genotype-dependent differences in arsenic metabolism among the studies. However, AS3MT 12390 (rs3740393) and 14458 (rs11191439) were consistently related to arsenic methylation regardless of the study population: AS3MT 12390 (rs3740393) affected the second step of methylation of arsenic, whereas 14458 (rs11191439) affected the first methylation step. PMID:26411936

  12. Probing Electronic, Structural, and Charge Transfer Properties of Organic Semiconductor/Inorganic Oxide Interfaces Using Field-Effect Transistors

    NASA Astrophysics Data System (ADS)

    Spalenka, Josef Wade

    Interfaces between organic semiconductors and inorganic oxides provide the functionality for devices including field-effect transistors (FETs) and organic photovoltaics. Organic FETs are sensitive to the physical structure and electronic properties of the few molecular layers of material at the interface between the semiconducting channel and the gate dielectric, and provide quantitative information such as the field-effect mobility of charge carriers and the concentration of trapped charge. In this thesis, FET interfaces between organic small-molecule semiconductors and SiO2, and donor/acceptor interfaces between organic small-molecules and the wide bandgap semiconductor ZnO are studied using electrical measurements of field-effect transistor devices. Monolayer-scale films of dihexyl sexithiophene are shown to have higher hole mobility than other monolayer organic semiconductors, and the origin of the high mobility is discussed. Studies of the crystal structure of the monolayer using X-ray structural probes and atomic force microscopy reveal the crystal structure is different in the monolayer regime compared to thicker films and bulk crystals. Progress and remaining challenges are discussed for in situ X-ray diffraction studies of the dynamic changes in the local crystal structure in organic monolayers due to charge carriers generated during the application of electric fields from the gate electrode in working FETs. Studies were conducted of light sensitive organic/inorganic interfaces that are modified with organic molecules grafted to the surface of ZnO nanoparticles and thin films. These interfaces are models for donor/acceptor interfaces in photovoltaics. The process of exciton dissociation at the donor/acceptor interface was sensitive to the insulating or semiconducting molecules grafted to the ZnO, and the photoinduced charge transfer process is measured by the threshold voltage shift of FETs during illumination. Charge transfer between light sensitive donor

  13. Mechanisms of inorganic nitrous oxide production in soils during nitrification and their dependence on soil properties

    NASA Astrophysics Data System (ADS)

    Heil, Jannis; Liu, Shurong; Vereecken, Harry; Brüggemann, Nicolas

    2014-05-01

    Nitrous oxide (N2O) is an important anthropogenic greenhouse gas and today's single most ozone depleting substance. Soils have been identified as the major source of N2O. Microbial nitrification and denitrification are considered the major N2O emission sources. However, N2O production in soils, especially during nitrification, is far from being completely understood. Several abiotic reactions involving the nitrification intermediate hydroxylamine (NH2OH) have been identified leading to N2O emissions, but are being neglected in most current studies. However, it is known that NH2OH can be oxidized by several soil constituents to form N2O. For better mitigation strategies it is mandatory to understand the underlying processes of N2O production during nitrification and their controlling factors. We studied N2O emissions from different soils in laboratory incubation experiments. Soils covered a wide range of land use types from arable to grassland and forest. Soil incubations were conducted with and without the addition of NH2OH at conditions favorable for nitrification with non-sterile as well as with sterile samples. N2O and, additionally, CO2 evolution were analyzed using gas chromatography. To get insight into the dynamics of N2O formation, N2O production from NH2OH was quantified online using quantum cascade laser absorption spectroscopy. Furthermore, isotope ratio mass spectrometry was used to analyze the isotopic signature of the produced N2O (i.e. δ15N, δ18O, and 15N site preference). We observed large differences in N2O emissions between different soils upon the addition of NH2OH. While a forest soil sample with pH < 3 showed hardly any reaction to the addition of NH2OH, a very high and immediate formation of N2O was observed in a cropland soil sample at neutral pH. N2O production after NH2OH addition was also observed in autoclaved samples, which confirmed an abiotic production mechanism. Further, isotopic signatures of N2O could be used to differentiate

  14. Oxidation state-differentiated measurement of aqueous inorganic arsenic by continuous flow electrochemical arsine generation coupled to gas-phase chemiluminescence detection.

    PubMed

    Sengupta, Mrinal K; Dasgupta, Purnendu K

    2011-12-15

    The electrochemical reduction of inorganic As on a graphite cathode depends on the current density. We observed that while only inorganic As(III) is reduced to AsH(3) at low current densities, at high current densities both forms of inorganic As are reduced. We describe a unique electrochemical reactor in which the cylindrical anode compartment is isolated from the outer concentric cathode compartment by a Nafion tube in which a hole is deliberately made and the entire anode compartment is inside the cylindrical cavity of a small volume (∼115 μL) cathode chamber. The evolved arsine is then quantitated by gas-phase chemiluminescence (GPCL) reaction with ozone; the latter is generated from oxygen formed during electrolysis. For the dimensions used, inorganic As(III) can be selectively determined at a current of 0.1 A while total inorganic As (both As(III) and As(V)) respond equally at an applied electrolysis current at 0.85 A, without any sample treatment. For a 1-mL sample, the system provides a limit of detection (LOD, S/N = 3) of 0.09 μg/L for total As (i = 0.85 A) and an LOD of 0.76 μg/L for As(III) (i = 0.10 A); As(V) is obtained by difference. Comparison of ICP-MS results for total As in groundwater samples that span a large range of concentration and total inorganic As determined by the present method showed a high correlation (r(2) = 0.9975) and a near unity slope. The basic electrochemical arsine generation technique and current-differentiated oxidation state speciation should be applicable as the front end to many other arsenic measurements techniques, including atomic spectrometry. PMID:22035322

  15. Decompression-Induced Crystallization of Hydrous Basalt

    NASA Astrophysics Data System (ADS)

    Teasdale, R.; Brooker, R. A.

    2014-12-01

    Decompression-induced crystallization of hydrous basalt during magma ascent from 1.5 kb (150 MPa) is quantified using isothermal decompression TZM experiments. The starting composition is a synthetic glass based on the 1921 Kilauea basalt, with 1% H2O added. In all cases, the liquidus phase is aluminous spinel, followed by clinopyroxene, then plagioclase. The plagioclase liquidus temperatures for isobaric (equilibrium) experiments range from 1175°C (at 1.5 kb) to 1217°C (at 200b), which are 35-75°C hotter than predicted by MELTS (Ghiorso & Sack 1995). Experiments were decompressed at 1kb/hr and quenched at 800, 400, 200, or 100b for three temperatures (1160°, 1150°, and 1140°C). Plagioclase crystals formed during decompression have long axes that range from less than 1 micron to 20 microns. Increasing decompression yields larger plagioclase crystal sizes and aspect ratios for experiments at equal temperatures. However, the number of crystals does not vary systematically, indicating that crystallization is dominated by growth rather than nucleation during decompression. Plagioclase compositions for experiments were measured with University of Bristol's Electron Microprobe and the Hyperprobe with Field Emission Gun. Plagioclase compositions from equilibrium experiments (An60-An80) span the range of those from decompression experiments (An60-An73). Equilibrium experiments generated higher An compositions at lower pressures (500b) than at higher pressure (1.5kb) but do not systematically vary with temperature. Variations in plagioclase compositions are minimal above H2O saturation (100-200°C, based on Papale et al., 2006). Below H2O saturation, An content decreases slightly, by approximately 4% An. One application of this work is better characterization of groundmass crystallization in hydrous basalt as it traverses the conduit during eruption. This work also provides a means of distinguishing groundmass plagioclase related to decompression from crystals

  16. Inorganic mercury causes pancreatic beta-cell death via the oxidative stress-induced apoptotic and necrotic pathways

    SciTech Connect

    Chen Yawen; Huang Chunfa; Yang Chingyao; Yen Chengchieh; Tsai Kehsung; Liu Shinghwa

    2010-03-15

    Mercury is a well-known highly toxic metal. In this study, we characterize and investigate the cytotoxicity and its possible mechanisms of inorganic mercury in pancreatic beta-cells. Mercury chloride (HgCl{sub 2}) dose-dependently decreased the function of insulin secretion and cell viability in pancreatic beta-cell-derived HIT-T15 cells and isolated mouse pancreatic islets. HgCl{sub 2} significantly increased ROS formation in HIT-T15 cells. Antioxidant N-acetylcysteine effectively reversed HgCl{sub 2}-induced insulin secretion dysfunction in HIT-T15 cells and isolated mouse pancreatic islets. Moreover, HgCl{sub 2} increased sub-G1 hypodiploids and annexin-V binding in HIT-T15 cells, indicating that HgCl{sub 2} possessed ability in apoptosis induction. HgCl{sub 2} also displayed several features of mitochondria-dependent apoptotic signals including disruption of the mitochondrial membrane potential, increase of mitochondrial cytochrome c release and activations of poly (ADP-ribose) polymerase (PARP) and caspase 3. Exposure of HIT-T15 cells to HgCl{sub 2} could significantly increase both apoptotic and necrotic cell populations by acridine orange/ethidium bromide dual staining. Meanwhile, HgCl{sub 2} could also trigger the depletion of intracellular ATP levels and increase the LDH release from HIT-T15 cells. These HgCl{sub 2}-induced cell death-related signals could be significantly reversed by N-acetylcysteine. The intracellular mercury levels were markedly elevated in HgCl{sub 2}-treated HIT-T15 cells. Taken together, these results suggest that HgCl{sub 2}-induced oxidative stress causes pancreatic beta-cell dysfunction and cytotoxicity involved the co-existence of apoptotic and necrotic cell death.

  17. No effect of H2O degassing on the oxidation state of hydrous rhyolite magmas: a comparison of pre- and post-eruptive Fe2+ concentrations in six obsidian samples from the Mexican and Cascade arcs

    NASA Astrophysics Data System (ADS)

    Waters, L.; Lange, R. A.

    2011-12-01

    The extent to which degassing affects the oxidation state of arc magmas is widely debated. Several researchers have examined how degassing of mixed H-C-O-S-Cl fluids may change the Fe3+/FeT ratio of magmas, and it has been proposed that degassing may induce either oxidation or reduction depending on the initial oxidation state. A commonly proposed oxidation reaction is related to H2O degassing: H2O (melt) + 2FeO (melt) = H2 (fluid) + Fe2O3 (melt). Another mechanism by which H2O degassing can affect the iron redox state is if dissolved water affects the activity of ferrous and/or ferric iron in the melt. Although Moore et al. (1995) presented experiments showing no evidence of an affect of dissolved water on the activity of the ferric-ferrous ratio in silicate melts, other experimental results (e.g., Baker and Rutherford, 1996; Gaillard et al., 2001; 2003) indicate that there may be such an effect in rhyolite liquids. It has long been understood that rhyolites, owing to their low total iron concentrations, are more sensitive than other magma types to degassing-induced change in redox state. Therefore, a rigorous test of whether H2O degassing affects the redox state of arc magmas is best evaluated on rhyolites. In this study, a comparison is made between the pre-eruptive (pre-degassing) Fe2+ concentrations in six, phenocryst-poor (<5%), fresh, glassy obsidian samples with their post-eruptive (post-degassing) Fe2+ concentrations. Near-liquidus co-precipitation of two Fe-Ti oxides allows the pre-eruptive oxygen fugacity and temperature to be calculated in each rhyolite using the oxygen barometer and thermometer of Ghiorso and Evans (2008). Temperatures range from 793 (± 19) to 939 (± 15) °C, and ΔNNO values (log10fO2 of sample - log10fO2 of Ni-NiO buffer) range from -0.4 to +1.4. These ΔNNO values allow the ferric-ferrous ratio in the liquid to be calculated, using the experimental calibration of Kress and Carmichael (1991), which relates melt composition (not

  18. Size-controlled synthesis and formation mechanism of manganese oxide OMS-2 nanowires under reflux conditions with KMnO4 and inorganic acids

    NASA Astrophysics Data System (ADS)

    Zhang, Qin; Cheng, Xiaodi; Qiu, Guohong; Liu, Fan; Feng, Xionghan

    2016-05-01

    This study presents a simplified approach for size-controlled synthesis of manganese oxide octahedral molecular sieve (OMS-2) nanowires using potassium permanganate (KMnO4) and different inorganic acids (HCl, HNO3, and H2SO4) under reflux conditions. The morphology and nanostructure of the synthesized products are characterized by X-ray diffraction, Ar adsorption, and electron microscopy analysis, in order to elucidate the controlling effects of acid concentration and type as well as the formation mechanism of OMS-2 nanowires. The concentration of inorganic acid is a crucial factor controlling the phase of the synthesized products. OMS-2 nanowires are obtained with HCl at the concentration ≥0.96 mol/L or with HNO3 and H2SO4 at the concentrations ≥0.72 mol/L. Differently, the type of inorganic acid effectively determines the particle size of OMS-2 nanowires. When the acid is changed from HCl to HNO3 and H2SO4 in the reflux system, the average length of OMS-2 declines significantly by 60-70% (1104-442 and 339 nm), with minor decreased in the average width (43-39 and 34 nm). The formation of OMS-2 nanowires under reflux conditions with KMnO4 and inorganic acids involves a two-step process, i.e., the initial formation of layered manganese oxides, and subsequent transformation to OMS-2 via a dissolution-recrystallization process under acidic conditions. The proposed reflux route provides an alternative approach for synthesizing OMS-2 nanowires as well as other porous nano-crystalline OMS materials.

  19. Size-controlled synthesis and formation mechanism of manganese oxide OMS-2 nanowires under reflux conditions with KMnO4 and inorganic acids

    NASA Astrophysics Data System (ADS)

    Zhang, Qin; Cheng, Xiaodi; Qiu, Guohong; Liu, Fan; Feng, Xionghan

    2016-05-01

    This study presents a simplified approach for size-controlled synthesis of manganese oxide octahedral molecular sieve (OMS-2) nanowires using potassium permanganate (KMnO4) and different inorganic acids (HCl, HNO3, and H2SO4) under reflux conditions. The morphology and nanostructure of the synthesized products are characterized by X-ray diffraction, Ar adsorption, and electron microscopy analysis, in order to elucidate the controlling effects of acid concentration and type as well as the formation mechanism of OMS-2 nanowires. The concentration of inorganic acid is a crucial factor controlling the phase of the synthesized products. OMS-2 nanowires are obtained with HCl at the concentration ≥0.96 mol/L or with HNO3 and H2SO4 at the concentrations ≥0.72 mol/L. Differently, the type of inorganic acid effectively determines the particle size of OMS-2 nanowires. When the acid is changed from HCl to HNO3 and H2SO4 in the reflux system, the average length of OMS-2 declines significantly by 60-70% (1104-442 and 339 nm), with minor decreased in the average width (43-39 and 34 nm). The formation of OMS-2 nanowires under reflux conditions with KMnO4 and inorganic acids involves a two-step process, i.e., the initial formation of layered manganese oxides, and subsequent transformation to OMS-2 via a dissolution-recrystallization process under acidic conditions. The proposed reflux route provides an alternative approach for synthesizing OMS-2 nanowires as well as other porous nano-crystalline OMS materials.

  20. Elasticity of Hydrous Phases in Subduction Zones- Geophysical Implications

    NASA Astrophysics Data System (ADS)

    Mookherjee, M.; Mainprice, D.

    2014-12-01

    Globally, subduction zones are region associated with earthquakes and volcanic activities, both involving risk to local populations. These processes are intimately related to the thermodynamic stability and instabilty of hydrous phases that are subducted with the down going slab. These phases sequestrate several wt % of water in their crystallographic structure and can account for significant proportion of the hydrogen budget of the upper mantle , transition zone and perhaps the top of the lower mantle. In order to quantify the degree of mantle hydration, we need to have a good understanding of the elastic properties of layered hydrous phases, the effects of temperature, and pressure and relate them to seismological observables, such as the velocity and its anisotropy. Using first principle simulations, we have investigated several layered hydrous phases, including the important minerals antigorite, talc, and chlorite. These results are complementary to the recent experimental Brillouin Scattering results at ambient conditions. Based on the full elastic constant tensor we note that these hydrous phases have significant shear wave anisotropy and often have unusual pressure dependence of the anisotropy. Together with elasticity data, thermodynamic predictions of phase stability and experimental plastic deformation studies it is apparent that these layered hydrous phases could account for the large delay times observed in certain subduction zone settings, such as Ryukyu trench. Acknowledgement- MM is supported by the US National Science Foundation grant (EAR-1250477). MM acknowledges computing resources (request # EAR130015) from the Extreme Science and Engineering Discovery Environment (XSEDE), which is supported by National Science Foundation grant number OCI-1053575.

  1. Characteristics of oxidative homolytic alkylation of imidazoles and organic-inorganic hybrid extended networks from large aromatic building blocks

    NASA Astrophysics Data System (ADS)

    Li, Kunhao

    The discovery of the dramatic in vitro antimalarial activity of 2-iodo-L-histidine and 2-fluoro-L-histidine, as well as their in vivo limitations, has prompted a systematic search for novel 2-substituted imidazoles and bioimidazoles as agents against human malaria. Previous research has shown that the regioselective alkyl free radical substitution on imidazoles and bioimidazoles could serve as a simple and efficient route to a wide variety of 2-alkylimidazoles. In this research, this methodology was successfully extended to include alkyl radicals substituted with various functional groups such as amide or ester. While this novel methodology should be of some synthetic utility when tertiary radicals are used, poorer yields are usually encountered in the cases of primary radicals. In the second part of this dissertation, a series of novel ligands containing multiple ortho-bis(organothio) groups were synthesized and their coordination and network forming properties were studied in the context of crystalline organic-inorganic hybrid extended networks. For the syntheses of HRTTs [2,3,6,7,10,11-hexakis(alkylthio)triphenylenes], a simpler, safer and higher yielding one-pot process was developed. Quenching the hexa-anions (formed when sodium methylthiolate was refluxed with hexabromotriphenylene) with alkyl halides or acid chlorides afforded HRTTs. This newly developed process was also successfully expanded to the pyrene system. In the syntheses of unsymmetrically substituted triphenlyenes, it was shown for the first time that the oxidative cyclization process is applicable to thioether containing systems, pointing to a novel strategy for the preparation of this type of unsymmetrically substituted triphenlyenes. Treating these novel ligands with various metal salts [i.e. bismuth(III) chloride and bismuth(III) bromide] under carefully controlled conditions resulted in a series of air-stable semiconductive coordination networks. Their single crystal structures were

  2. Roles of inorganic oxide nanoparticles on extraction efficiency of electrospun polyethylene terephthalate nanocomposite as an unbreakable fiber coating.

    PubMed

    Bagheri, Habib; Roostaie, Ali

    2015-01-01

    In the present work, the roles of inorganic oxide nanoparticles on the extraction efficiency of polyethylene terephthalate-based nanocomposites were extensively studied. Four fiber coatings based on polyethylene terephthalate nanocomposites containing different types of nanoparticles along with a pristine polyethylene terephthalate polymer were conveniently electrospun on stainless steel wires. The applicability of new fiber coatings were examined by headspace-solid phase microextraction of some environmentally important volatile organic compound such as benzene, toluene, ethylbenzene and xylene (BTEX), as model compounds, from aqueous samples. Subsequently, the extracted analytes were transferred into a gas chromatography by thermal desorption. Parameters affecting the morphology and capability of the prepared nanocomposites including the type of nanoparticles and their doping levels along with the coating time were optimized. Four types of nanoparticles including Fe3O4, SiO2, CoO and NiO were examined as the doping agents and among them the presence of SiO2 in the prepared nanocomposite was prominent. The homogeneity and the porous surface structure of the SiO2-polyethylene terephthalate nanocomposite were confirmed by scanning electron microscopy indicating that the nanofibers diameters were lower than 300 nm. In addition, important parameters influencing the extraction and desorption process such as temperature and extraction time, ionic strength and desorption conditions were optimized. Eventually, the developed method was validated by gas chromatography-mass spectrometry. Under optimized conditions, the relative standard deviation values for a double distilled water spiked with the selected volatile organic compounds at 50 ng L(-1) were 2-7% (n=3) while the limits of detection were between 0.7 and 0.9 ng L(-1). The method was linear in the concentration range of 10 to 1,000 ng L(-1) (R(2)>0.9992). Finally, the developed method was applied to the analysis of

  3. Continental flood basalts derived from the hydrous mantle transition zone

    NASA Astrophysics Data System (ADS)

    Wang, Xuan-Ce; Wilde, Simon A.; Li, Qiu-Li; Yang, Ya-Nan

    2015-07-01

    It has previously been postulated that the Earth's hydrous mantle transition zone may play a key role in intraplate magmatism, but no confirmatory evidence has been reported. Here we demonstrate that hydrothermally altered subducted oceanic crust was involved in generating the late Cenozoic Chifeng continental flood basalts of East Asia. This study combines oxygen isotopes with conventional geochemistry to provide evidence for an origin in the hydrous mantle transition zone. These observations lead us to propose an alternative thermochemical model, whereby slab-triggered wet upwelling produces large volumes of melt that may rise from the hydrous mantle transition zone. This model explains the lack of pre-magmatic lithospheric extension or a hotspot track and also the arc-like signatures observed in some large-scale intracontinental magmas. Deep-Earth water cycling, linked to cold subduction, slab stagnation, wet mantle upwelling and assembly/breakup of supercontinents, can potentially account for the chemical diversity of many continental flood basalts.

  4. Continental flood basalts derived from the hydrous mantle transition zone.

    PubMed

    Wang, Xuan-Ce; Wilde, Simon A; Li, Qiu-Li; Yang, Ya-Nan

    2015-07-14

    It has previously been postulated that the Earth's hydrous mantle transition zone may play a key role in intraplate magmatism, but no confirmatory evidence has been reported. Here we demonstrate that hydrothermally altered subducted oceanic crust was involved in generating the late Cenozoic Chifeng continental flood basalts of East Asia. This study combines oxygen isotopes with conventional geochemistry to provide evidence for an origin in the hydrous mantle transition zone. These observations lead us to propose an alternative thermochemical model, whereby slab-triggered wet upwelling produces large volumes of melt that may rise from the hydrous mantle transition zone. This model explains the lack of pre-magmatic lithospheric extension or a hotspot track and also the arc-like signatures observed in some large-scale intracontinental magmas. Deep-Earth water cycling, linked to cold subduction, slab stagnation, wet mantle upwelling and assembly/breakup of supercontinents, can potentially account for the chemical diversity of many continental flood basalts.

  5. Creation of giant two-dimensional crystal of zinc oxide nanodisk by method of single-particle layer of organo-modified inorganic fine particles.

    PubMed

    Meng, Qi; Honda, Nanami; Uchida, Saki; Hashimoto, Kazuaki; Shibata, Hirobumi; Fujimori, Atsuhiro

    2015-09-01

    In this study, the formation and structure of a single-particle layer of organo-zinc oxide are investigated using surface-pressure-area (π-A) isotherms, out-of-plane X-ray diffraction (XRD) analysis, and atomic force microscopy (AFM). Further, techniques for achieving the solubilization of inorganic fine particles in general solvents have been proposed, and a single-particle layer has been formed using such an inorganic solution as a "spreading solution" for an interfacial film. Surface modification of ZnO is performed using a long-chain carboxylic acid. Accordingly, a regular arrangement of ZnO can be easily achieved in order to overcome the relatively weak van der Walls interactions between inorganic materials. A condensed Langmuir monolayer of these particles is also formed. A multiparticle layered structure is constructed by the Langmuir-Blodgett (LB) technique. Out-of-plane XRD measurement results for a single-particle layer of organo-ZnO clearly show a sharp peak at 42 Å. This peak is attributed to the distance between ZnO layers. The AFM image of this single-particle layer of organo-ZnO shows a particle assembly with a uniform height of 60 nm. These aggregated particles form large two-dimensional crystals. In other words, a regular periodic structure along the c-axis and a condensed single-particle layer had been fabricated using Langmuir and LB techniques.

  6. Introduction to Homogenous Catalysis with Ruthenium-Catalyzed Oxidation of Alcohols: An Experiment for Undergraduate Advanced Inorganic Chemistry Students

    ERIC Educational Resources Information Center

    Miecznikowski, John R.; Caradonna, John P.; Foley, Kathleen M.; Kwiecien, Daniel J.; Lisi, George P.; Martinez, Anthony M.

    2011-01-01

    A three-week laboratory experiment, which introduces students in an advanced inorganic chemistry course to air-sensitive chemistry and catalysis, is described. During the first week, the students synthesize RuCl[subscript 2](PPh[subscript 3])[subscript 3]. During the second and third weeks, the students characterize the formed coordination…

  7. Lipid oxidative damage and distribution of inorganic arsenic and its metabolites in the rat nervous system after arsenite exposure: influence of alpha tocopherol supplementation.

    PubMed

    García-Chávez, Erika; Jiménez, Ismael; Segura, Bertha; Del Razo, Luz M

    2006-12-01

    Inorganic arsenic (iAs) exposure causes peripheral neuropathy. Oxidative effects caused by iAs exposure in peripheral nerves have been incompletely characterized. This study analyzed arsenic and lipid oxidative damage in the brain, spinal cord, and sciatic and sensory sural nerves following arsenite exposure. This study also explored whether alpha tocopherol (alpha-TOC) administration mitigates arsenite-induced oxidative damage. Thiobarbituric acid-reactive substance (TBARS) levels and distributions of iAs and its metabolites were evaluated in male Wistar rats following 30d of sodium arsenite exposure (10mg/kg bodyweight (bw)/d, by gavage). A second group also received alpha-TOC (125mg/kg bw/d, by gavage) during the final 20d of arsenite administration. Arsenite exposure caused increased TBARS levels within each region of the nervous system; oxidative stress was most pronounced in the sural and sciatic nerves. In addition there was a positive quadratic relationship between TBARS levels and the concentration of arsenicals found in the nervous system (r(2)=0.878, p<0.001). Dimethylarsenic was the predominant metabolite of iAs found. Animals alpha-TOC-treated had a 1.7-5.2-fold reduction in TBARS levels when compared with rats that received iAs alone. These results suggest that oxidative damage may be the main mechanism of toxicity induced by exposure of the peripheral nervous system to arsenite and that such damage could be attenuated by alpha-TOC-supplementation.

  8. Influence of wastewater sludge treatment using combined peroxyacetic acid oxidation and inorganic coagulants re-flocculation on characteristics of extracellular polymeric substances (EPS).

    PubMed

    Zhang, Weijun; Cao, Bingdi; Wang, Dongsheng; Ma, Teng; Xia, Hua; Yu, Dehong

    2016-01-01

    Extracellular polymeric substances (EPS) are highly hydrated biopolymers and play important roles in bioflocculation, floc stability, and solid-water separation processes. Destroying EPS structure will result in sludge reduction and release of trapped water. In this study, the effects of combined process of peracetic acid (PAA) pre-oxidation and chemical re-flocculation on morphological properties and distribution and composition of EPS of the resultant sludge flocs were investigated in detail to gain insights into the mechanism involved in sludge treatment. It was found that sludge particles were effectively solubilized and protein-like substances were degraded into small molecules after PAA oxidation. A higher degradation of protein-like substances was observed at acid environments under PAA oxidation. Microscopic analysis revealed that no integral sludge floc was observed after oxidation with PAA at high doses. The floc was reconstructed with addition of inorganic coagulants (polyaluminium chloride (PACl) and ferric chloride (FeCl3)) and PACl performed better in flocculation due to its higher charge neutralization and bridging ability. Combined oxidative lysis and chemical re-flocculation provide a novel solution for sludge treatment.

  9. Influence of wastewater sludge treatment using combined peroxyacetic acid oxidation and inorganic coagulants re-flocculation on characteristics of extracellular polymeric substances (EPS).

    PubMed

    Zhang, Weijun; Cao, Bingdi; Wang, Dongsheng; Ma, Teng; Xia, Hua; Yu, Dehong

    2016-01-01

    Extracellular polymeric substances (EPS) are highly hydrated biopolymers and play important roles in bioflocculation, floc stability, and solid-water separation processes. Destroying EPS structure will result in sludge reduction and release of trapped water. In this study, the effects of combined process of peracetic acid (PAA) pre-oxidation and chemical re-flocculation on morphological properties and distribution and composition of EPS of the resultant sludge flocs were investigated in detail to gain insights into the mechanism involved in sludge treatment. It was found that sludge particles were effectively solubilized and protein-like substances were degraded into small molecules after PAA oxidation. A higher degradation of protein-like substances was observed at acid environments under PAA oxidation. Microscopic analysis revealed that no integral sludge floc was observed after oxidation with PAA at high doses. The floc was reconstructed with addition of inorganic coagulants (polyaluminium chloride (PACl) and ferric chloride (FeCl3)) and PACl performed better in flocculation due to its higher charge neutralization and bridging ability. Combined oxidative lysis and chemical re-flocculation provide a novel solution for sludge treatment. PMID:26584344

  10. Hydrous silica coatings: occurrence, speciation of metals, and environmental significance.

    PubMed

    Schindler, Michael; Durocher, Jennifer L; Abdu, Yassir; Hawthorne, Frank C

    2009-12-01

    Si-enriched coatings form on the surface of silicate minerals under acidic conditions. Although they are often only a few nanometers thick, their large specific surface area may control the interaction between silicate minerals in acidic soils, aquifers, and mine tailings. Micrometer thick, hydrous-silica coatings occur on the surface of a granite outcrop in contact with acidic pond water at the Coppercliff mine-tailings area in the Greater City of Sudbury, Ontario, and are ideal to study the concentration and speciation of metals and metalloids inside Si-enriched coatings. These coatings have higher average concentrations of Cr, Mn, Co, Ni, Cu, Zn, and Pb than coatings composed of schwertmannite, Fe(8)O(8)(OH)(4.4)(SO(4))(1.8) (H(2)O)(8.4). Microscopic and spectroscopic examination of the hydrous-silica coating indicates the occurrence of Fe- and Cu-Zn-oxy-hydroxide particles, tetrahedrally coordinated Fe(3+) and a high proportion of M-O-Si bonds (M = metal). These observations suggest that metals occur either finely distributed in the hydrous-silica matrix or in oxy-hydroxide particles. The latter particles are products of the diffusion of metals into the hydrous silica and the subsequent nucleation of oxy-hydroxide phases.

  11. Reproductive toxicity of inorganic mercury exposure in adult zebrafish: Histological damage, oxidative stress, and alterations of sex hormone and gene expression in the hypothalamic-pituitary-gonadal axis.

    PubMed

    Zhang, Qun-Fang; Li, Ying-Wen; Liu, Zhi-Hao; Chen, Qi-Liang

    2016-08-01

    Mercury (Hg) is a prominent environmental contaminant that causes a variety of adverse effects on aquatic organisms. However, the mechanisms underlying inorganic Hg-induced reproductive impairment in fish remains largely unknown. In this study, adult zebrafish were exposed to 0 (control), 15 and 30μg Hg/l (added as mercuric chloride, HgCl2) for 30days, and the effects on histological structure, antioxidant status and sex hormone levels in the ovary and testis, as well as the mRNA expression of genes involved in the hypothalamic-pituitary-gonadal (HPG) axis were analyzed. Exposure to Hg caused pathological lesions in zebrafish gonads, and changed the activities and mRNA levels of antioxidant enzymes (catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPx)) as well as the content of glutathione (GSH) and malondialdehyde (MDA). In females, although ovarian 17β-estradiol (E2) content remained relatively stable, significant down-regulation of lhβ, gnrh2, gnrh3, lhr and erα were observed. In males, testosterone (T) levels in the testis significantly decreased after Hg exposure, accompanied by down-regulated expression of gnrh2, gnrh3, fshβ and lhβ in the brain as well as fshr, lhr, ar, cyp17 and cyp11b in the testis. Thus, our study indicated that waterborne inorganic Hg exposure caused histological damage and oxidative stress in the gonads of zebrafish, and altered sex hormone levels by disrupting the transcription of related HPG-axis genes, which could subsequently impair the reproduction of fish. Different response of the antioxidant defense system, sex hormone and HPG-axis genes between females and males exposed to inorganic Hg indicated the gender-specific regulatory effect by Hg. To our knowledge, this is the first time to explore the effects and mechanisms of inorganic Hg exposure on reproduction at the histological, enzymatic and molecular levels, which will greatly extend our understanding on the mechanisms underlying of reproductive

  12. Adsorption of isoxaflutole degradates to aluminum and iron hydrous oxides

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Isoxaflutole (IXF) is a pre-emergence herbicide that has been marketed as a substitute for atrazine. It is rapidly transformed to a more stable and soluble diketonitrile degradate (DKN) after field application and, subsequently, DKN can be further degraded to a benzoic acid derivative (BA) within so...

  13. Adsorption of Isoxaflutole Degradates to Hydrous Metal Oxide Surfaces

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Isoxaflutole (IXF) is a pre-emergence herbicide that is rapidly transformed to a more stable and soluble diketonitrile degradate (DKN) after field application and, subsequently, DKN can be degraded to a benzoic acid derivative (BA) within soil. Due to the short half-life (t1/2) of IXF and the signif...

  14. Abundance retrieval of hydrous minerals around the Mars Science Laboratory landing site in Gale crater, Mars

    NASA Astrophysics Data System (ADS)

    Lin, Honglei; Zhang, Xia; Shuai, Tong; Zhang, Lifu; Sun, Yanli

    2016-02-01

    The detection of hydrous minerals on Mars is of great importance for revealing the early water environment as well as possible biotic activity. However, few studies focus on abundance retrieval of hydrous minerals for some difficulties. In this paper, we studied the area around the Mars Science Laboratory (MSL) landing site, to identify hydrous minerals and retrieve their abundance. Firstly, the distribution of hydrous minerals was extracted using their hydration features. Then, a sparse unmixing algorithm was applied along with the CRISM spectral library to retrieve the abundance of hydrous minerals in this area. As a result, seven hydrous minerals were retrieved, i.e. actinolite, montmorillonite, saponite, jarosite, halloysite, szomolnokite and magnesite and, the total concentration of all hydrous minerals was as high as 40 vol% near the lower reaches of Mount Sharp. Our results were consistent with results from related research and the in-situ analysis of the MSL rover Curiosity.

  15. Influence of crustal dust and sea spray supermicron particle concentrations and acidity on inorganic NO3- aerosol during the 2013 Southern Oxidant and Aerosol Study

    SciTech Connect

    Allen, Hannah M.; Draper, Danielle C.; Ayres, Benjamin R.; Ault, Andrew P.; Bondy, Amy L.; Takahama, S.; Modini, Robert; Baumann, K.; Edgerton, Eric S.; Knote, Christoph; Laskin, Alexander; Wang, Bingbing; Fry, Juliane L.

    2015-09-25

    The inorganic aerosol composition was measured in the southeastern United States, a region that exhibits high aerosol mass loading during the summer, as part of the 1 June to 15 July 2013 Southern Oxidant and Aerosol Study (SOAS) campaign. Measurements using a Monitor for AeRosols and GAses (MARGA), an ion chromatograph coupled with a wet rotating denuder and a steam-jet aerosol collector for monitoring of ambient inorganic gas and aerosol species, revealed two periods of high aerosol nitrate (NO3 ) concentrations during the campaign. These periods of high nitrate were correlated with increased concentrations of coarse mode mineral or sea spray aerosol species, particularly Na+ and Ca2+, and with a shift towards aerosol with larger (1 to 2.5 um) diameters. We suggest this nitrate aerosol forms by multiphase reactions of HNO3 and particles, reactions that are facilitated by transport of mineral dust and sea spray aerosol from a source within the United States. The observed high aerosol acidity prevents the formation of NH4NO3, the inorganic nitrogen species often dominant in fine-mode aerosol at higher pH. Calculation of the rate of the heterogeneous uptake of HNO3 on mineral aerosol supports the conclusion that aerosol NO3 is produced primarily by this process, and is likely limited by the availability of mineral dust surface area. Modeling of NO3 and HNO3 by thermodynamic equilibrium models (ISORROPIA II and E-AIM) reveals the importance of including mineral cations in the southeastern United States to accurately balance ion species and predict gas/aerosol phase partitioning.

  16. Zeolite catalysis in the synthesis of isobutylene from hydrous ethanol

    NASA Astrophysics Data System (ADS)

    Phillips, Cory Bernard

    1999-11-01

    This work deals with the synthesis of isobutylene from a hydrous ethanol feedstock over zeolites. The synthesis is accomplished in three steps: (1) low-temperature direct ethanol conversion to ethylene on H-ZSM-5 zeolite, (2) ethylene conversion to butene products over metal-exchanged zeolites, and (3) butene skeletal rearrangement to isobutylene over FER zeolites. The key to understanding and optimizing each synthesis step lies in the ability to control and regulate the zeolite acidity (Bronsted and Lewis)---both strength and number. Therefore, the continuous temperature programmed amine desorption (CTPAD) technique was further developed to simultaneously count the Bronsted acid sites and quantitatively characterize their strength. The adsorption of ethanol, reaction products, amines, coke and ethanol-derived residue (EDR) were monitored gravimetrically using the highly sensitive, novel Tapered Element Oscillating Microreactor (TEOM) apparatus. The TEOM was also used also in conjunction with CTPAD to characterize Bronsted acidity which is a new application for the instrument. For the first synthesis step, a parallel reaction exists which simultaneously produces diethyl ether and ethylene directly over H-ZSM-5. The reaction rates for each pathway were measured directly using a differential reactor operating at low temperatures (<473 K). Water in the ethanol feed enhances the rate of ethylene formation. A mechanism and kinetic expression are proposed for this reaction over H-ZSM-5, with diethyl-ether desorption and ethylene formation as the rate limiting steps. Heat of adsorption values measured from the independent microcalorimetry work reported in the literature are incorporated into the kinetic analysis which reduces the number of regressed parameters. For the remaining synthesis steps, several zeolite structures (ZSM-5, Y, FER) partially exchanged with Pd, Ti, Ni and Au were prepared and tested. It was determined from this screening study that the zeolites

  17. Efficient visible light-driven water oxidation catalyzed by an all-inorganic copper-containing polyoxometalate.

    PubMed

    Yu, Li; Du, Xiaoqiang; Ding, Yong; Chen, Hongli; Zhou, Panpan

    2015-12-21

    [Cu5(OH)4(H2O)2(A-α-SiW9O33)2](10-) (1) was tested as the first copper-containing polyoxometalate catalyst for O2 production via visible light-driven water oxidation. Multiple experiments confirm that 1 is an active and dominant catalyst during water oxidation. PMID:26468511

  18. Geochemistry of dissolved inorganic carbon in a Coastal Plain aquifer. 1. Sulfate from confining beds as an oxidant in microbial CO2 production

    USGS Publications Warehouse

    Chapelle, F.H.; McMahon, P.B.

    1991-01-01

    A primary source of dissolved inorganic carbon (DIC) in the Black Creek aquifer of South Carolina is carbon dioxide produced by microbially mediated oxidation of sedimentary organic matter. Groundwater chemistry data indicate, however, that the available mass of inorganic electron acceptors (oxygen, Fe(III), and sulfate) and observed methane production is inadequate to account for observed CO2 production. Although sulfate concentrations are low (approximately 0.05-0.10 mM) in aquifer water throughout the flow system, sulfate concentrations are greater in confining-bed pore water (0.4-20 mM). The distribution of culturable sulfate-reducing bacteria in these sediments suggests that this concentration gradient is maintained by greater sulfate-reducing activity in sands than in clays. Calculations based on Fick's Law indicate that possible rates of sulfate diffusion to aquifer sediments are sufficient to explain observed rates of CO2 production (about 10-5 mmoll-1 year-1), thus eliminating the apparent electron-acceptor deficit. Furthermore, concentrations of dissolved hydrogen in aquifer water are in the range characteristic of sulfate reduction (2-6 nM), which provides independent evidence that sulfate reduction is the predominant terminal electron-accepting process in this system. The observed accumulation of pyrite- and calcite-cemented sandstones at sand-clay interfaces is direct physical evidence that these processes have been continuing over the history of these sediments. ?? 1991.

  19. DNA-base guanine as hydrogen getter and charge-trapping layer embedded in oxide dielectrics for inorganic and organic field-effect transistors.

    PubMed

    Lee, Junyeong; Park, Ji Hoon; Lee, Young Tack; Jeon, Pyo Jin; Lee, Hee Sung; Nam, Seung Hee; Yi, Yeonjin; Lee, Younjoo; Im, Seongil

    2014-04-01

    DNA-base small molecules of guanine, cytosine, adenine, and thymine construct the DNA double helix structure with hydrogen bonding, and they possess such a variety of intrinsic benefits as natural plentitude, biodegradability, biofunctionality, low cost, and low toxicity. On the basis of these advantages, here, we report on unprecedented useful applications of guanine layer as hydrogen getter and charge trapping layer when it is embedded into a dielectric oxide of n-channel inorganic InGaZnO and p-channel organic heptazole field effect transistors (FETs). The embedded guanine layer much improved the gate stability of inorganic FETs gettering many hydrogen atoms in the gate dielectric layer of FET, and it also played as charge trapping layer to which the voltage pulse-driven charges might be injected from channel, resulting in a threshold voltage (Vth) shift of FETs. Such shift state is very ambient-stable and almost irrevocable even under a high electric-field at room temperature. So, Boolean logics are nicely demonstrated by using our FETs with the guanine-embedded dielectric. The original Vth is recovered only under high energy blue photons by opposite voltage pulse (charge-ejection), which indicates that our device is also applicable to nonvolatile photo memory.

  20. Influence of crustal dust and sea spray supermicron particle concentrations and acidity on inorganic NO3− aerosol during the 2013 Southern Oxidant and Aerosol Study

    DOE PAGESBeta

    Allen, H. M.; Draper, D. C.; Ayres, B. R.; Ault, A.; Bondy, A.; Takahama, S.; Modini, R. L.; Baumann, K.; Edgerton, E.; Knote, C.; et al

    2015-09-25

    Inorganic aerosol composition was measured in the southeastern United States, a region that exhibits high aerosol mass loading during the summer, as part of the 2013 Southern Oxidant and Aerosol Study (SOAS) campaign. Measurements using a Monitor for AeRosols and GAses (MARGA) revealed two periods of high aerosol nitrate (NO3−) concentrations during the campaign. These periods of high nitrate were correlated with increased concentrations of supermicron crustal and sea spray aerosol species, particularly Na+ and Ca2+, and with a shift towards aerosol with larger (1 to 2.5 μm) diameters. We suggest this nitrate aerosol forms by multiphase reactions of HNO3more » and particles, reactions that are facilitated by transport of crustal dust and sea spray aerosol from a source within the United States. The observed high aerosol acidity prevents the formation of NH4NO3, the inorganic nitrogen species often dominant in fine-mode aerosol at higher pH. In addition, calculation of the rate of the heterogeneous uptake of HNO3 on mineral aerosol supports the conclusion that aerosol NO3− is produced primarily by this process, and is likely limited by the availability of mineral cation-containing aerosol surface area. Modeling of NO3− and HNO3 by thermodynamic equilibrium models (ISORROPIA II and E-AIM) reveals the importance of including mineral cations in the southeastern United States to accurately balance ion species and predict gas–aerosol phase partitioning.« less

  1. Efficient hybrid organic-inorganic light emitting diodes with self-assembled dipole molecule deposited metal oxides

    NASA Astrophysics Data System (ADS)

    Park, Ji Sun; Lee, Bo Ram; Lee, Ju Min; Kim, Ji-Seon; Kim, Sang Ouk; Song, Myoung Hoon

    2010-06-01

    We investigate the effect of self-assembled dipole molecules (SADMs) on ZnO surface in hybrid organic-inorganic polymeric light-emitting diodes (HyPLEDs). Despite the SADM being extremely thin, the magnitude and orientation of SADM dipole moment effectively influenced the work function of the ZnO. As a consequence, the charge injection barrier between the conduction band of the ZnO and the lowest unoccupied molecular orbital of poly(9,9'-dioctylfluorene)-co-benzothiadiazole could be efficiently controlled resulting that electron injection efficiency is remarkably enhanced. The HyPLEDs modified with a negative dipolar SADM exhibited enhanced device performances, which correspond to approximately a fourfold compared to those of unmodified HyPLEDs.

  2. The Identity of Hydrous Defects Controlling the Rheology of Olivine

    NASA Astrophysics Data System (ADS)

    Faul, U.; David, E. C.; Cline, C. J., II; Berry, A.; Jackson, I.

    2015-12-01

    The reduction of the creep strength of minerals due to the presence of water is well established. The nature of the relevant hydrous defect(s) is perhaps less well understood. Standard treatments examine intrinsic defects of a pure crystal, but impurity-related defects are not usually considered. Natural olivine contains monovalent (Na) and trivalent (e.g. Al) trace elements in concentrations that exceed the concentration of intrinsic defects by up to an order of magnitude. They therefore are potentially important as agents for water-weakening. Hydrated defects - both intrinsic and impurity-related - systematically affect infrared absorption spectra, which can therefore be used for their identification and quantification. Experiments with olivine in contact with a range of buffer assemblages (e.g. MgO and enstatite) have shown that the infrared spectra of natural olivine can only be reproduced experimentally in the presence of titanium. Doping with a range of trivalent cations shows systematics in the infrared spectra related to the ionic radius of the dopants, confirming that the spectra are sensitive to the bonding environment and can be used to identify particular defects. To investigate the relationship between hydrous, titanium-related defects and creep strength we conducted deformation experiments on synthetic Fo90 olivine that was buffered by enstatite and doped with titanium. The infrared spectra of the deformed samples show absorption bands at the same wave numbers and relative intensity as natural olivine, indicating that the experimental samples contain the same hydrous defects. Fitting the creep data from samples with a range of water contents determined from these absorption bands shows a near linear relationship between strain rate and water content, consistent with published observations. The experiments therefore show that the rheology of hydrous olivine is determined by hydrated impurity-related defects rather than intrinsic point defects.

  3. Structure and stability of hydrous minerals at high pressure

    NASA Technical Reports Server (NTRS)

    Duffy, T. S.; Fei, Y.; Meade, C.; Hemley, R. J.; Mao, H. K.

    1994-01-01

    The presence of even small amounts of hydrogen in the Earth's deep interior may have profound effects on mantle melting, rheology, and electrical conductivity. The recent discovery of a large class of high-pressure H-bearing silicates further underscores the potentially important role for hydrous minerals in the Earth's mantle. Hydrogen may also be a significant component of the Earth's core, as has been recently documented by studies of iron hydride at high pressure. In this study, we explore the role of H in crystal structures at high pressure through detailed Raman spectroscopic and x ray diffraction studies of hydrous minerals compressed in diamond anvil cells. Brucite, Mg(OH)2, has a simple structure and serves as an analogue for the more complex hydrous silicates. Over the past five years, this material has been studied at high pressure using shock-compression, powder x ray diffraction, infrared spectroscopy, Raman spectroscopy, and neutron diffraction. In addition, we have recently carried out single-crystal synchrotron x-ray diffraction on Mg(OH)2 and Raman spectroscopy on Mg(OD)2 at elevated pressure. From all these studies, an interesting picture of the crystal chemical behavior of this material at high pressure is beginning to emerge. Some of the primary conclusions are as follows: First, hydrogen bonding is enhanced by the application of pressure. Second, layered minerals which are elastically anisotropic at low pressure may not be so at high pressure. Furthermore, the brucite data place constraints on the effect of hydrogen on seismic velocities and density at very high pressure. Third, the stability of hydrous minerals may be enhanced at high P by subtle structural rearrangements that are difficult to detect using traditional probes and require detailed spectroscopic analyses. Finally, brucite appears to be unique in that it undergoes pressure-induced disordering that is confined solely to the H-containing layers of the structure.

  4. Uranium oxidation: characterization of oxides formed by reaction with water

    SciTech Connect

    Fuller, E.L. Jr.; Smyrl, N.R.; Condon, J.B.; Eager, M.H.

    1983-04-27

    Three different uranium oxide samples have been characterized with respect to the different preparation techniques. Results show that the water reaction with uranium metal occurs cyclically forming laminar layers of oxide which spall off due to the strain at the oxide/metal interface. Single laminae are released if liquid water is present due to the prizing penetration at the reaction zone. The rate of reaction of water with uranium is directly proportional to the amount of adsorbed water on the oxide product. Rapid transport is effected through the open hydrous oxide product. Dehydration of the hydrous oxide irreversibly forms a more inert oxide which cannot be rehydrated to the degree that prevails in the original hydrous product of uranium oxidation with water. 27 figures.

  5. Arsenic, inorganic

    Integrated Risk Information System (IRIS)

    Arsenic , inorganic ; CASRN 7440 - 38 - 2 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinoge

  6. Heat capacity, configurational heat capacity and fragility of hydrous magmas

    NASA Astrophysics Data System (ADS)

    Di Genova, D.; Romano, C.; Giordano, D.; Alletti, M.

    2014-10-01

    The glassy and liquid heat capacities of four series of dry and hydrous natural glasses and magma as a function of temperature and water content (up to 19.9 mol%) were investigated using differential scanning calorimetry (DSC). The analyzed compositions are basalt, latite, trachyte and pantellerite. The results of this study indicate that the measured heat capacity of glasses (Cpg) is a linear function of composition and is well reproduced by the empirical model of Richet (1987). For the investigated glasses, the partial molar heat capacity of water can be considered as independent of composition, in agreement with Bouhifd et al. (2006). For hydrous liquids, the heat capacity (Cpliq) decreases nonlinearly with increasing water content. Previously published models, combined with the partial molar heat capacity of water from the literature, are not able to reproduce our experimental data in a satisfactory way. We estimated the partial molar heat capacity of water (CpH2O) in hydrous magma over a broad compositional range. The proposed value is 41 ± 3 J mol-1 K-1. Water strongly affects the configurational heat capacity at the glass transition temperature [Cpconf (Tg)]. An increases of Cpconf (Tg) with water content was measured for the polymerized liquids (trachyte and pantellerite), while the opposite behavior was observed for the most depolymerized liquids (basalt and latite). Structural and rheological implications of this behavior are discussed in light of the presented results.

  7. Oxidative treatment of bromide-containing waters: formation of bromine and its reactions with inorganic and organic compounds--a critical review.

    PubMed

    Heeb, Michèle B; Criquet, Justine; Zimmermann-Steffens, Saskia G; von Gunten, Urs

    2014-01-01

    Bromide (Br(-)) is present in all water sources at concentrations ranging from ≈ 10 to >1000 μg L(-1) in fresh waters and about 67 mg L(-1) in seawater. During oxidative water treatment bromide is oxidized to hypobromous acid/hypobromite (HOBr/OBr(-)) and other bromine species. A systematic and critical literature review has been conducted on the reactivity of HOBr/OBr(-) and other bromine species with inorganic and organic compounds, including micropollutants. The speciation of bromine in the absence and presence of chloride and chlorine has been calculated and it could be shown that HOBr/OBr(-) are the dominant species in fresh waters. In ocean waters, other bromine species such as Br2, BrCl, and Br2O gain importance and may have to be considered under certain conditions. HOBr reacts fast with many inorganic compounds such as ammonia, iodide, sulfite, nitrite, cyanide and thiocyanide with apparent second-order rate constants in the order of 10(4)-10(9)M(-1)s(-1) at pH 7. No rate constants for the reactions with Fe(II) and As(III) are available. Mn(II) oxidation by bromine is controlled by a Mn(III,IV) oxide-catalyzed process involving Br2O and BrCl. Bromine shows a very high reactivity toward phenolic groups (apparent second-order rate constants kapp ≈ 10(3)-10(5)M(-1)s(-1) at pH 7), amines and sulfamides (kapp ≈ 10(5)-10(6)M(-1)s(-1) at pH 7) and S-containing compounds (kapp ≈ 10(5)-10(7)M(-1)s(-1) at pH 7). For phenolic moieties, it is possible to derive second-order rate constants with a Hammett-σ-based QSAR approach with [Formula in text]. A negative slope is typical for electrophilic substitution reactions. In general, kapp of bromine reactions at pH 7 are up to three orders of magnitude greater than for chlorine. In the case of amines, these rate constants are even higher than for ozone. Model calculations show that depending on the bromide concentration and the pH, the high reactivity of bromine may outweigh the reactions of chlorine during

  8. Oxidative treatment of bromide-containing waters: formation of bromine and its reactions with inorganic and organic compounds--a critical review.

    PubMed

    Heeb, Michèle B; Criquet, Justine; Zimmermann-Steffens, Saskia G; von Gunten, Urs

    2014-01-01

    Bromide (Br(-)) is present in all water sources at concentrations ranging from ≈ 10 to >1000 μg L(-1) in fresh waters and about 67 mg L(-1) in seawater. During oxidative water treatment bromide is oxidized to hypobromous acid/hypobromite (HOBr/OBr(-)) and other bromine species. A systematic and critical literature review has been conducted on the reactivity of HOBr/OBr(-) and other bromine species with inorganic and organic compounds, including micropollutants. The speciation of bromine in the absence and presence of chloride and chlorine has been calculated and it could be shown that HOBr/OBr(-) are the dominant species in fresh waters. In ocean waters, other bromine species such as Br2, BrCl, and Br2O gain importance and may have to be considered under certain conditions. HOBr reacts fast with many inorganic compounds such as ammonia, iodide, sulfite, nitrite, cyanide and thiocyanide with apparent second-order rate constants in the order of 10(4)-10(9)M(-1)s(-1) at pH 7. No rate constants for the reactions with Fe(II) and As(III) are available. Mn(II) oxidation by bromine is controlled by a Mn(III,IV) oxide-catalyzed process involving Br2O and BrCl. Bromine shows a very high reactivity toward phenolic groups (apparent second-order rate constants kapp ≈ 10(3)-10(5)M(-1)s(-1) at pH 7), amines and sulfamides (kapp ≈ 10(5)-10(6)M(-1)s(-1) at pH 7) and S-containing compounds (kapp ≈ 10(5)-10(7)M(-1)s(-1) at pH 7). For phenolic moieties, it is possible to derive second-order rate constants with a Hammett-σ-based QSAR approach with [Formula in text]. A negative slope is typical for electrophilic substitution reactions. In general, kapp of bromine reactions at pH 7 are up to three orders of magnitude greater than for chlorine. In the case of amines, these rate constants are even higher than for ozone. Model calculations show that depending on the bromide concentration and the pH, the high reactivity of bromine may outweigh the reactions of chlorine during

  9. The Chassigny meteorite - A cumulate dunite with hydrous amphibole-bearing melt inclusions

    NASA Technical Reports Server (NTRS)

    Floran, R. J.; Prinz, M.; Hlava, P. F.; Keil, K.; Nehru, C. E.; Hinthorne, J. R.

    1978-01-01

    The Chassigny meteorite, an iron-rich dunite (Fo 68), is a moderately shocked olivine achondrite or chassignite with features indicative of a cumulate origin with some subsolidus annealing. The evidence that the meteorite experienced shock pressures of approximately 150-200 kbar is described. Kaersutitic amphibole, found only in melt inclusions, represents the first extraterrestrial occurence of hydrous amphibole and the first meteoritic amphibole type other than fluorichterite. Fractionation data indicate that Chassigny formed under relatively more oxidizing conditions than most other achondrites, which implies that its parental melt could not have been directly derived from a chondritic composition in a simple single-stage process. Similarities and differences with the Brachina meteorite, the only other meteorite of the Chassigny type, are considered.

  10. Oxidations of Organic and Inorganic Substrates by Superoxo-, hydroperoxo-, and oxo-compounds of the transition metals.

    SciTech Connect

    Vasbinder, Michael John

    2006-01-01

    Chapters 1 and 2 dealt with the chemistry of superoxo-, hydroperoxo-, and oxo- complexes of chromium, rhodium and cobalt. Chapter 3 dealt with the mechanism of oxygen-atom transfer catalyzed by an oxo-complex of rhenium. In Chapter 1, it was shown that hydroperoxometal complexes of cobalt and rhodium react with superoxochromium and chromyl ions, generating reduced chromium species while oxidizing the hydroperoxometal ions to their corresponding superoxometal ions. It was shown that the chromyl and superoxochromium ions are the more powerful oxidants. Evidence supports hydrogen atom transfer from the hydroperoxometal ion to the oxidizing superoxochromium or chromyl ion as the reaction mechanism. There is a significant H/D kinetic isotope effect. Comparisons to the rate constants of other known hydrogen atom transfer reactions show the expected correlation with bond dissociation energies. In Chapter 2, it was found that the superoxometal complexes Cr{sub aq}OO2+ and Rh(NH3)4(H2O)OO2+ oxidize stable nitroxyl radicals of the TEMPO series with rate constants that correlate with the redox potentials of both the oxidant and reductant. These reactions fit the Marcus equation for electron transfer near the theoretical value. Acid catalysis is important to the reaction, especially the thermodynamically limited cases involving Rh(NH3)4(H2O)OO2+ as the oxidant. The rate constants are notably less than those measured in the reaction between the same nitroxyl radicals and other strong free-radical oxidants, an illustration of the delocalized and stabilized nature of the superoxometal ions. Chapter 3 showed that oxo-rhenium catalysts needed a nucleophile to complete the catalytic oxygen-atom transfer from substituted pyridine-N-oxides to triphenylphosphine. The reaction was studied by introducing various pyridine-derived nucleophiles and monitoring their effect on the rate, then

  11. Effect Of Inorganic, Synthetic And Naturally Occurring Chelating Agents On Fe(II) Mediated Advanced Oxidation Of Chlorophenols

    EPA Science Inventory

    This study examines the feasibility and application of Advanced Oxidation Technologies (AOTs) for the treatment of chlorophenols that are included in US EPA priority pollutant list. A novel class of sulfate/hydroxyl radical-based homogeneous AOTs (Fe(II)/PS, Fe(II)/PMS, Fe(II)/H...

  12. Reactive uptake of N2O5 to internally mixed inorganic and organic particles: the role of organic carbon oxidation state and inferred organic phase separations

    NASA Astrophysics Data System (ADS)

    Gaston, C. J.; Thornton, J. A.; Ng, N. L.

    2014-06-01

    We measured N2O5 reactive uptake onto mixed organic/inorganic submicron particles using organic compounds with a variety of oxidation states (using mainly atomic O : C ratios as a proxy) and molecular weights. The organic mass fraction, organic molecular composition, and relative humidity (RH) were varied to assess their effects separately on the N2O5 uptake coefficient, γ(N2O5). At a constant RH, mixtures of organic components having an O : C < 0.5 with ammonium bisulfate significantly suppressed the uptake of N2O5(g) compared to pure ammonium bisulfate, even at small organic mass fractions (e.g., ≤ 15%). The effect of the organic component became less pronounced at higher RH. In general, highly oxygenated organic components (O : C > 0.8) had a smaller or even negligible impact on N2O5(g) uptake at all RHs probed; however, a few exceptions were observed. Notably, γ(N2O5) for mixtures of ammonium bisulfate with polyethylene glycol (PEG), PEG-300 (O : C = 0.56), decreased nearly linearly as the PEG mass fraction increased at constant RH until leveling off at the value measured for pure PEG. The response of γ(N2O5) to increasing PEG mass fraction was similar to that measured on ambient atmospheric particles as a function of organic mass fraction. The effects of the organic mass fraction on γ(N2O5), for mixtures having an O : C < ~0.8, were best described using a standard resistor model of reactive uptake assuming the particles had an RH-dependent inorganic core-organic shell morphology. This model suggests that the N2O5 diffusivity and/or solubility in the organic layer is up to a factor of 20 lower compared to aqueous solution particles, and that the diffusivity, solubility, and reactivity of N2O5 within organic coatings and particles depend upon both RH and the molecular composition of the organic medium. We use these dependencies and ambient measurements of organic aerosol from the global aerosol mass spectrometry (AMS) database to show that the typical

  13. Reactive uptake of N2O5 to internally mixed inorganic and organic particles: the role of organic carbon oxidation state and inferred organic phase separations

    NASA Astrophysics Data System (ADS)

    Gaston, C. J.; Thornton, J. A.; Ng, N. L.

    2013-12-01

    We measured N2O5 reactive uptake onto mixed organic/inorganic submicron particles using organic compounds with a variety of oxidation states (using mainly atomic O : C ratios as a proxy) and molecular weights. The organic mass fraction, organic molecular composition, and relative humidity (RH) were varied to separately assess their effect on the N2O5 uptake coefficient, γ(N2O5). At a constant RH, mixtures of organic components having an O : C < 0.5 with ammonium bisulfate (ABS) significantly suppressed the uptake of N2O 0.8) had a smaller or even negligible impact on N2O5 uptake at all RHs probed; however, a few exceptions were observed. Notably, γ(N2O5) for mixtures of ABS with polyethylene glycol (PEG), PEG-300 (O : C = 0.56), decreased nearly linearly as the PEG mass fraction increased at constant RH until leveling off at the value measured on pure PEG. The response of γ(N2O5) to increasing PEG mass fraction was similar to that measured on ambient atmospheric particles as a function of organic mass fraction. The effects of the organic mass fraction on γ(N2O5), for mixtures having an O : C < ~ 0.8, were best described using a standard resistor model of reactive uptake assuming the particles had a RH dependent inorganic core-organic shell morphology. This model suggests that the N2O5 diffusivity and/or solubility in the organic layer is up to a factor of 20 lower compared to aqueous solution particles, and that the diffusivity, solubility, and reactivity of N2O5 within organic coatings and particles depend upon both RH and the molecular composition of the organic medium. We use these dependencies and ambient measurements of organic aerosol from the global aerosol mass spectrometry (AMS) database to show that the typical impact of organic aerosol

  14. Graphene oxide-TiO2 composite solid phase extraction combined with graphite furnace atomic absorption spectrometry for the speciation of inorganic selenium in water samples.

    PubMed

    Zhang, Yanan; Chen, Beibei; Wu, Shaowei; He, Man; Hu, Bin

    2016-07-01

    In this paper, a method of graphene oxide (GO)-TiO2 composite solid phase extraction followed by graphite furnace atomic absorption spectrometry (GFAAS) detection was proposed for the speciation of inorganic selenium in environmental waters. The adsorption behavior of inorganic Se(IV) and Se(VI) on the GO-TiO2(1:1) composite was investigated. It was found that Se(IV) was quantitatively retained on the GO-TiO2 composites within a wide pH range of 0.5-10, while Se(VI) was quantitatively adsorbed on GO-TiO2(1:1) composite at pH 0.5-2, and no obvious adsorption of Se(VI) within the pH range of 4-10 was found. By selecting pH 6.0, Se(IV) could be easily determined. After reduction of Se(VI), total Se was determined by the proposed method, and Se(VI) was calculated as the difference between the total Se and Se(IV). The factors affecting the separation/preconcentration of Se(IV) and Se(VI) were studied. Under the optimum conditions, the isothermal adsorption of Se(IV) on the GO-TiO2(1:1) composite fitted Langmuir model; a linear range over 0.1-12ngmL(-1) was obtained. The limit of detection (LOD) and precision of the method for Se(IV) was 0.04ngmL(-1) and 9.4% (cSe(IV)=0.5ngmL(-1), n=7), respectively. In order to verify the accuracy of the method, a standard water sample (GSBZ50031-94) was analyzed, and the determined value was in a good agreement to the certified value. The established method was applied to inorganic Se speciation in environmental water samples and the recovery of 87.4-102% was obtained for the spiked samples.

  15. Graphene oxide-TiO2 composite solid phase extraction combined with graphite furnace atomic absorption spectrometry for the speciation of inorganic selenium in water samples.

    PubMed

    Zhang, Yanan; Chen, Beibei; Wu, Shaowei; He, Man; Hu, Bin

    2016-07-01

    In this paper, a method of graphene oxide (GO)-TiO2 composite solid phase extraction followed by graphite furnace atomic absorption spectrometry (GFAAS) detection was proposed for the speciation of inorganic selenium in environmental waters. The adsorption behavior of inorganic Se(IV) and Se(VI) on the GO-TiO2(1:1) composite was investigated. It was found that Se(IV) was quantitatively retained on the GO-TiO2 composites within a wide pH range of 0.5-10, while Se(VI) was quantitatively adsorbed on GO-TiO2(1:1) composite at pH 0.5-2, and no obvious adsorption of Se(VI) within the pH range of 4-10 was found. By selecting pH 6.0, Se(IV) could be easily determined. After reduction of Se(VI), total Se was determined by the proposed method, and Se(VI) was calculated as the difference between the total Se and Se(IV). The factors affecting the separation/preconcentration of Se(IV) and Se(VI) were studied. Under the optimum conditions, the isothermal adsorption of Se(IV) on the GO-TiO2(1:1) composite fitted Langmuir model; a linear range over 0.1-12ngmL(-1) was obtained. The limit of detection (LOD) and precision of the method for Se(IV) was 0.04ngmL(-1) and 9.4% (cSe(IV)=0.5ngmL(-1), n=7), respectively. In order to verify the accuracy of the method, a standard water sample (GSBZ50031-94) was analyzed, and the determined value was in a good agreement to the certified value. The established method was applied to inorganic Se speciation in environmental water samples and the recovery of 87.4-102% was obtained for the spiked samples. PMID:27154702

  16. Comparative short-term inhalation toxicity of five organic diketopyrrolopyrrole pigments and two inorganic iron-oxide-based pigments

    PubMed Central

    Hofmann, Thomas; Ma-Hock, Lan; Strauss, Volker; Treumann, Silke; Rey Moreno, Maria; Neubauer, Nicole; Wohlleben, Wendel; Gröters, Sibylle; Wiench, Karin; Veith, Ulrich; Teubner, Wera; van Ravenzwaay, Bennard; Landsiedel, Robert

    2016-01-01

    Abstract Diketopyrrolopyrroles (DPP) are a relatively new class of organic high-performance pigments. The present inhalation and particle characterization studies were performed to compare the effects of five DPP-based pigments (coarse and fine Pigment Red 254, coarse and fine meta-chloro DPP isomer and one form of mixed chlorinated DPP isomers) and compare it to coarse and fine inorganic Pigment Red 101. Wistar rats were exposed head-nose to atmospheres of the respective materials for 6 h/day on 5 consecutive days. Target concentrations were 30 mg/m3 as high dose for all compounds and selected based occupational exposure limits for respirable nuisance dust. Toxicity was determined after end of exposure and after 3-week recovery using broncho-alveolar lavage fluid (BALF) and microscopic examinations of the entire respiratory tract. Mixed chlorinated DPP isomers and coarse meta-chloro DPP isomer caused marginal changes in BALF, consisting of slight increases of polymorphonuclear neutrophils, and in case of coarse meta-chloro DPP increased MCP-1 and osteopontin levels. Mixed chlorinated DPP isomers, Pigment Red 254, and meta-chloro DPP caused pigment deposits and phagocytosis by alveolar macrophages, slight hypertrophy/hyperplasia of the bronchioles and alveolar ducts, but without evidence of inflammation. In contrast, only pigment deposition and pigment phagocytosis were observed after exposure to Pigment Red 101. All pigments were tolerated well and caused only marginal effects in BALF or no effects at all. Only minor effects were seen on the lung by microscopic examination. There was no evidence of systemic inflammation based on acute-phase protein levels in blood. PMID:27387137

  17. Comparative short-term inhalation toxicity of five organic diketopyrrolopyrrole pigments and two inorganic iron-oxide-based pigments.

    PubMed

    Hofmann, Thomas; Ma-Hock, Lan; Strauss, Volker; Treumann, Silke; Rey Moreno, Maria; Neubauer, Nicole; Wohlleben, Wendel; Gröters, Sibylle; Wiench, Karin; Veith, Ulrich; Teubner, Wera; van Ravenzwaay, Bennard; Landsiedel, Robert

    2016-08-01

    Diketopyrrolopyrroles (DPP) are a relatively new class of organic high-performance pigments. The present inhalation and particle characterization studies were performed to compare the effects of five DPP-based pigments (coarse and fine Pigment Red 254, coarse and fine meta-chloro DPP isomer and one form of mixed chlorinated DPP isomers) and compare it to coarse and fine inorganic Pigment Red 101. Wistar rats were exposed head-nose to atmospheres of the respective materials for 6 h/day on 5 consecutive days. Target concentrations were 30 mg/m(3) as high dose for all compounds and selected based occupational exposure limits for respirable nuisance dust. Toxicity was determined after end of exposure and after 3-week recovery using broncho-alveolar lavage fluid (BALF) and microscopic examinations of the entire respiratory tract. Mixed chlorinated DPP isomers and coarse meta-chloro DPP isomer caused marginal changes in BALF, consisting of slight increases of polymorphonuclear neutrophils, and in case of coarse meta-chloro DPP increased MCP-1 and osteopontin levels. Mixed chlorinated DPP isomers, Pigment Red 254, and meta-chloro DPP caused pigment deposits and phagocytosis by alveolar macrophages, slight hypertrophy/hyperplasia of the bronchioles and alveolar ducts, but without evidence of inflammation. In contrast, only pigment deposition and pigment phagocytosis were observed after exposure to Pigment Red 101. All pigments were tolerated well and caused only marginal effects in BALF or no effects at all. Only minor effects were seen on the lung by microscopic examination. There was no evidence of systemic inflammation based on acute-phase protein levels in blood. PMID:27387137

  18. Ultrasonic-assisted degradation of phenazopyridine with a combination of Sm-doped ZnO nanoparticles and inorganic oxidants.

    PubMed

    Eskandarloo, Hamed; Badiei, Alireza; Behnajady, Mohammad A; Ziarani, Ghodsi Mohammadi

    2016-01-01

    Pure and samarium doped ZnO nanoparticles were synthesized by a sonochemical method and characterized by TEM, SEM, EDX, XRD, Pl, and DRS techniques. The average crystallite size of pure and Sm-doped ZnO nanoparticles was about 20 nm. The sonocatalytic activity of pure and Sm-doped ZnO nanoparticles was considered toward degradation of phenazopyridine as a model organic contaminant. The Sm-doped ZnO nanoparticles with Sm concentration of 0.4 mol% indicated a higher sonocatalytic activity (59%) than the pure ZnO (51%) and other Sm-doped ZnO nanoparticles. It was believed that Sm(3+) ion with optimal concentration (0.4 mol%) can act as superficial trapping for electrons in the conduction band of ZnO and delayed the recombination of charge carriers. The influence of the nature and concentration of various oxidants, including periodate, hydrogen peroxide, peroxymonosulfate, and peroxydisulfate on the sonocatalytic activity of Sm-doped ZnO nanoparticles was studied. The influence of the oxidants concentration (0.2-1.4 g L(-1)) on the degradation rate was established by the 3D response surface and the 2D contour plots. The results demonstrated that the utilizing of oxidants in combination with Sm-doped ZnO resulting in rapid removal of contaminant, which can be referable to a dual role of oxidants; (i) scavenging the generated electrons in the conduction band of ZnO and (ii) creating highly reactive radical species under ultrasonic irradiation. It was found that the Sm-doped ZnO and periodate combination is the most efficient catalytic system under ultrasonic irradiation.

  19. Oxidation of aqueous EDTA and associated organics and coprecipitation of inorganics by ambient iron-mediated aeration.

    PubMed

    Englehardt, James D; Meeroff, Daniel E; Echegoyen, Luis; Deng, Yang; Raymo, Françisco M; Shibata, Tomoyuki

    2007-01-01

    Cationic metal and radionuclide contaminants can be extracted from soils to groundwater with sequestering agents such as EDTA. However, EDTA must then be removed fromthe groundwater, by advanced oxidation or specialized biological treatment. In this work, aqueous individual metal-EDTA solutions were aerated with steel wool for 25 h, at ambient pH, temperature, and pressure. Removal of approximately 99% of EDTA (0.09-1.78 mM); glyoxylic acid (0.153 mM); chelated Cd2+ (0.94 and 0.0952 mM), Pb2+ (0.0502 mM), and Hg2+ (0.0419 mM); and free chromate and vanadate was shown. EDTA was oxidized to glyoxylic acid and formaldehyde, and metals/metalloids were coprecipitated together with iron oxyhydroxide floc. Free arsenite and arsenate were each removed at 99.97%. Free Sr2+, and chelated Ni2+ were removed at 92% and 63%, respectively. Similar removals were obtained from mixtures, including 99.996+/-0.004% removal of total arsenic (95% confidence). Traces of iminodiacetic acid, nitrilotriacetic acid, and ethylenediaminetriacetic acid were detected after 25 h. Results are consistent with first-order, solution-phase oxidation of EDTA and glyoxylic acid by ferryl ion and H202, respectively, with inhibition due to sludge accumulation, and equilibrium metal coprecipitation. This ambient process, to our knowledge previously unknown, agrees with recently reported findings and shows promise for remediation of metals, metalloids, and radionuclides in wastewater, soil, and sediment.

  20. Inorganic Graphene Analogs

    NASA Astrophysics Data System (ADS)

    Rao, C. N. R.; Maitra, Urmimala

    2015-07-01

    In the last four to five years, there has been a great resurgence of research on two-dimensional inorganic materials, partly because of the impetus received from graphene research. Unlike graphene, which is a gap-less material, most inorganic layered materials are semiconductors or insulators. Some of them, as exemplified by MoS2, exhibit unexpected properties, not unlike graphene, with possible applications. Thus, layered metal chalcogenides are being explored intensely, and MoS2 is emerging as a wonder material. In this article, we present the synthesis and properties of nanosheets composing single or few layers of these fascinating materials. Besides metal chalcogenides, boron nitride, borocarbonitrides (BxCyNz), metal oxides, and metal-organic frameworks are also discussed.

  1. Infrared spectroscopy and hydrogen isotope geochemistry of hydrous silicate glasses

    SciTech Connect

    Epstein, S.; Stolper, E.

    1992-01-01

    The focus of this project is the combined appication of infrared spectroscopy and stable isotope geochemistry to the study of hydrogen-bearing species dissolved in silicate melts and glasses. We are conducting laboratory experiments aimed at determining the fractionation of D and H between melt species (OH and H{sub 2}O) and hydrous vapor and the diffusivities of these species in glasses and melts. Knowledge of these parameters is critical to understanding the behavior of hydrogen isotopes during igneous processes and hydrothermal processes. These results also could be valuable in application of glass technology to development of nuclear waste disposal strategies.

  2. Seismic signature of a hydrous mantle transition zone

    NASA Astrophysics Data System (ADS)

    Thio, Vincent; Cobden, Laura; Trampert, Jeannot

    2016-01-01

    Although water has a major influence on tectonic and other geodynamic processes, little is known about its quantity and distribution within the deep Earth. In the last few decades, laboratory experiments on nominally anhydrous minerals (NAMs) of the transition zone have shown that these minerals can contain significant amounts of water, up to 3.3 wt%. In this study, we investigate if it is possible to use seismic observations to distinguish between a hydrous and anhydrous transition zone. We perform an extensive literature search of mineral experimental data, to generate a compilation of the water storage capacities, elastic parameters and phase boundary data for potentially hydrous minerals in the transition zone, and use thermodynamic modelling to compute synthetic seismic profiles of density, VP and VS at transition zone temperatures and pressures. We find that large uncertainties on the mineral phase equilibria (ca. 2 GPa) and elastic properties produce a wide range of seismic profiles. In particular, there is a lack of data at temperatures corresponding to those along a 1300 °C adiabat or hotter, which may be expected at transition zone pressures. Comparing our hydrous transition zone models with equivalent profiles at anhydrous conditions, we see that the depths of the 410 and 660 discontinuities cannot at present be used to map the water content of the transition zone due to these uncertainties. Further, while average velocities and densities inside the transition zone clearly decrease with increasing water content, there is a near-perfect trade-off with increases in temperature. It is therefore difficult to distinguish thermal from water effects, and the conventional view of a slow and thick transition zone for water and slow and thin transition zone for high temperature should be regarded with caution. A better diagnostic for water may be given by the average velocity gradients of the transition zone, which increase with increasing water content (but

  3. Seismic Signature of a Hydrous Mantle Transition Zone

    NASA Astrophysics Data System (ADS)

    Cobden, L. J.; Thio, V.; Trampert, J.

    2014-12-01

    The quantity and distribution of water inside the deep Earth has major consequences for tectonic and geodynamic processes, yet remains essentially unconstrained. Laboratory experiments on nominally anhydrous minerals (NAMs) of the mantle transition zone have indicated that these minerals in particular are capable of storing significant amounts of water. We pose the question of whether seismology can be used to distinguish a hydrous from an anhydrous transition zone. We perform an extensive literature search of the experimentally-determined elastic properties and phase equilibria of hydrous NAMs, and use thermodynamic modelling to predict the seismic properties (Vp, Vs and density) of these minerals at transition zone pressures and temperatures. We compare these models with their anhydrous counterparts, taking into account the (often large) uncertainties in the mineralogical data. We find that much experimental work remains to be done for completely defining the elastic parameters and phase equilibria of the hydrous minerals, and large uncertainties produce a wide range of possible seismic structures. This uncertainty makes it difficult to use metrics such as the depths of the 410 and 660 discontinuities for mapping transition zone water content. At the same time, average P and S wave velocities inside the transition zone are not helpful, since there is a near-perfect trade-off between changes in water content, changes in temperature and changes in iron content. Average velocity gradients, density and density gradients appear to be both sensitive to, and diagnostic of, the presence of water. However these parameters are difficult to resolve seismically. Potentially the impedance contrast at 410 may also be useful, depending on the partitioning of water between olivine and wadsleyite. From a seismological perspective, it would be most helpful for future experimental studies to focus on better constraining the phase boundaries in hydrous (Mg,Fe)2SiO4, since these

  4. Efficient automatic screening for Li ion conductive inorganic oxides with bond valence pathway models and percolation algorithm

    NASA Astrophysics Data System (ADS)

    Nakayama, Masanobu; Kimura, Mayumi; Jalem, Randy; Kasuga, Toshihiro

    2016-01-01

    Fast ion conductive solid oxide electrolytes are urgently needed because of the development of batteries, fuel cells, and sensors. Ab initio density functional theory can predict ionic conductivities with high accuracy, although it often requires large computational resources and time. In this paper, we use empirical bond valence relations [Adams et al., Phys. Status Solidi A 208, 1746 (2011)] and a percolation algorithm for fast, efficient, fully automated evaluation of migration energies for Li ion conduction in 14 olivine-type LiMXO4 compounds. The results showed a high correlation coefficient with the ab initio density functional theory (DFT) approach, indicating that our method could be attractive for identifying fast ion conductors in databases of numerous candidates.

  5. The research progress of Li-ion battery separators with inorganic oxide nanoparticles by electrospinning: A mini review

    NASA Astrophysics Data System (ADS)

    Chen, Hong-Li; Jiao, Xiao-Ning; Zhou, Jin-Tao

    2016-09-01

    The technology of Lithium-ion battery (LIB) separator has become more and more mature. But there are still many problems that needed to be resolved. For example, its mechanical strength is low relatively, thermal stability is bad and the porosity and electrochemical performance are imperfect. This paper introduces modification of electrospinning LIB separator from the way of adding nanoparticles, including SiO2, TiO2, Al2O3 and copper titanate oxide, etc. And addition methods include dissolving in dispersant, dissolving in polymer solution, coating and in situ method. The modified membranes possess higher ionic conductivity which can reach to the level of 10‑3s/cm.

  6. Inorganic and methylmercury levels in plasma are differentially associated with age, gender, and oxidative stress markers in a population exposed to mercury through fish consumption.

    PubMed

    Carneiro, Maria Fernanda Hornos; Grotto, Denise; Barbosa, Fernando

    2014-01-01

    This study aimed to determine the concentrations of plasma methylmercury (Me-Hg) and inorganic mercury (I-Hg) in a population exposed to Me-Hg. In addition, associations between each form of mercury (Hg) and gender, age, plasma selenium (Se), and oxidative stress markers were also investigated. The mean plasma I-Hg level was 5.7 μg/L while the mean for plasma Me-Hg was 3.6 μg/L, representing approximately 59 and 41% of the total Hg in blood, respectively. However, several plasma samples contained higher percentages of Me-Hg. Age displayed a direct linkage with plasma I-Hg levels, whereas gender did not correlate with any of the Hg species. In addition, fish intake was only correlated with and a predictor of plasma Me-Hg, suggesting that plasma I-Hg levels originated endogenously through a demethylation reaction that needs to be verified. Further, plasma Me-Hg was markedly correlated with adverse effects to a greater extent than plasma I-Hg and may be considered a valuable, reliable internal dose biomarker for Hg in chronically Me-Hg- exposed individuals.

  7. Hydrous mantle transition zone indicated by ringwoodite included within diamond.

    PubMed

    Pearson, D G; Brenker, F E; Nestola, F; McNeill, J; Nasdala, L; Hutchison, M T; Matveev, S; Mather, K; Silversmit, G; Schmitz, S; Vekemans, B; Vincze, L

    2014-03-13

    The ultimate origin of water in the Earth's hydrosphere is in the deep Earth--the mantle. Theory and experiments have shown that although the water storage capacity of olivine-dominated shallow mantle is limited, the Earth's transition zone, at depths between 410 and 660 kilometres, could be a major repository for water, owing to the ability of the higher-pressure polymorphs of olivine--wadsleyite and ringwoodite--to host enough water to comprise up to around 2.5 per cent of their weight. A hydrous transition zone may have a key role in terrestrial magmatism and plate tectonics, yet despite experimental demonstration of the water-bearing capacity of these phases, geophysical probes such as electrical conductivity have provided conflicting results, and the issue of whether the transition zone contains abundant water remains highly controversial. Here we report X-ray diffraction, Raman and infrared spectroscopic data that provide, to our knowledge, the first evidence for the terrestrial occurrence of any higher-pressure polymorph of olivine: we find ringwoodite included in a diamond from Juína, Brazil. The water-rich nature of this inclusion, indicated by infrared absorption, along with the preservation of the ringwoodite, is direct evidence that, at least locally, the transition zone is hydrous, to about 1 weight per cent. The finding also indicates that some kimberlites must have their primary sources in this deep mantle region. PMID:24622201

  8. Fabrication and characterization of an inorganic gold and silica nanoparticle mediated drug delivery system for nitric oxide

    NASA Astrophysics Data System (ADS)

    Das, Amitava; Mukherjee, Priyabrata; Singla, Sumit K.; Guturu, Praveen; Frost, Megan C.; Mukhopadhyay, Debabrata; Shah, Vijay H.; Ranjan Patra, Chitta

    2010-07-01

    Nitric oxide (NO) plays an important role in inhibiting the development of hepatic fibrosis and its ensuing complication of portal hypertension by inhibiting human hepatic stellate cell (HSC) activation. Here we have developed a gold nanoparticle and silica nanoparticle mediated drug delivery system containing NO donors, which could be used for potential therapeutic application in chronic liver disease. The gold nanoconjugates were characterized using several physico-chemical techniques such as UV-visible spectroscopy and transmission electron microscopy. Silica nanoconjugates were synthesized and characterized as reported previously. NO released from gold and silica nanoconjugates was quantified under physiological conditions (pH = 7.4 at 37 °C) for a substantial period of time. HSC proliferation and the vascular tube formation ability, manifestations of their activation, were significantly attenuated by the NO released from these nanoconjugates. This study indicates that gold and silica nanoparticle mediated drug delivery systems for introducing NO could be used as a strategy for the treatment of hepatic fibrosis or chronic liver diseases, by limiting HSC activation.

  9. Inorganic Materials

    NASA Astrophysics Data System (ADS)

    Černý, Radovan

    The separation of compounds by inorganic/organic boundary is of less importance for the structure determination by diffraction methods. More important for the diffraction is how the atoms build up larger building units and the crystal itself. A molecular/non-molecular boundary is therefore relevant for the choice of a structure determination method. Non-molecular compounds - also called extended solids - are constructed by bonds that extend "infinitely" in three dimensions through a crystal. These non-molecular crystals usually crystallize with higher symmetries, and atoms often occupy special Wyckoff positions. A review of actual methodology is given first, and then highlights and pitfalls of structure determination from powder diffraction, its problems and their solutions are shown and discussed using selected examples.

  10. In adenosine A2B knockouts acute treatment with inorganic nitrate improves glucose disposal, oxidative stress, and AMPK signaling in the liver

    PubMed Central

    Peleli, Maria; Hezel, Michael; Zollbrecht, Christa; Persson, A. Erik G.; Lundberg, Jon O.; Weitzberg, Eddie; Fredholm, Bertil B.; Carlström, Mattias

    2015-01-01

    Rationale: Accumulating studies suggest that nitric oxide (NO) deficiency and oxidative stress are central pathological mechanisms in type 2 diabetes (T2D). Recent findings demonstrate therapeutic effects by boosting the nitrate-nitrite-NO pathway, which is an alternative pathway for NO formation. This study aimed at investigating the acute effects of inorganic nitrate on glucose and insulin signaling in adenosine A2B receptor knockout mice (A−/−2B), a genetic mouse model of impaired metabolic regulation. Methods: Acute effects of nitrate treatment were investigated in aged wild-type (WT) and A−/−2B mice. One hour after injection with nitrate (0.1 mmol/kg, i.p.) or placebo, metabolic regulation was evaluated by intraperitoneal glucose and insulin tolerance tests. NADPH oxidase-mediated superoxide production and AMPK phosphorylation were measured in livers obtained from non-treated or glucose-treated mice, with or without prior nitrate injection. Plasma was used to determine insulin resistance (HOMA-IR) and NO signaling. Results: A−/−2B displayed increased body weight, reduced glucose clearance, and attenuated overall insulin responses compared with age-matched WT mice. Nitrate treatment increased circulating levels of nitrate, nitrite and cGMP in the A−/−2B, and improved glucose clearance. In WT mice, however, nitrate treatment did not influence glucose clearance. HOMA-IR increased following glucose injection in the A−/−2B, but remained at basal levels in mice pretreated with nitrate. NADPH oxidase activity in livers from A−/−2B, but not WT mice, was reduced by nitrate treatment. Livers from A−/−2B displayed reduced AMPK phosphorylation compared with WT mice, and this was increased by nitrate treatment. Finally, injection with the anti-diabetic agent metformin induced similar therapeutic effects in the A−/−2B as observed with nitrate. Conclusion: The A−/−2B mouse is a genetic mouse model of metabolic syndrome. Acute treatment

  11. Analysis of Mineral Assemblages Containing Unstable Hydrous Phases

    NASA Astrophysics Data System (ADS)

    Vaniman, D. T.; Wilson, S. A.; Bish, D. L.; Chipera, S.

    2011-12-01

    Minerals in many environments can be treated as durable phases that preserve a record of their formation. However many minerals, especially those with hydrogen-bonded H2O molecules as part of their structure, are ephemeral and are unlikely to survive disturbance let alone removal from their environment of formation. Minerals with exceptionally limited stability such as meridianiite (Mg-sulfate 11 hydrate), ikaite (Ca-carbonate 6 hydrate), and mirabilite (Na-sulfate 10 hydrate) are very susceptible to destabilization during analysis, and even modest changes in temperature or relative humidity can lead to change in hydration state or deliquescence. The result may be not only loss of the salt hydrate but dissolution of other salts present, precipitation of new phases, and ion exchange between the concentrated solution and otherwise unaffected phases. Exchange of H2O molecules can also occur in solid-vapor systems without any liquid involvement; moreover, recent work has shown that cation exchange between smectite and sulfate hydrates can occur without any liquid phase present other than a presumed thin film at the salt-silicate interface. Among hydrous silicates, clay minerals are susceptible to cation exchange and similar alteration can be expected for zeolites, palagonite, and possibly other hydrous silicate alteration products. Environmentally sensitive phases on Mars, such as meridianiite, may occur at higher latitudes or in the subsurface where permafrost may be present. Accurate determination of the presence and paragenesis of such minerals will be important for understanding the near-surface hydrogeology of Mars, and in situ analysis may be the only way to obtain this information. Access to the subsurface may be required, yet the act of exposure by excavation or drilling can itself lead to rapid degradation as the sample is exposed or brought to the surface for analysis. Mars is not the only body with which to be concerned, for similar concerns can be raised

  12. Geochemical signatures of thermochemical sulfate reduction in controlled hydrous pyrolysis experiments

    USGS Publications Warehouse

    Zhang, T.; Ellis, G.S.; Walters, C.C.; Kelemen, S.R.; Wang, K.-s.; Tang, Y.

    2008-01-01

    A series of gold tube hydrous pyrolysis experiments was conducted in order to investigate the effect of thermochemical sulfate reduction (TSR) on gas generation, residual saturated hydrocarbon compositional alteration, and solid pyrobitumen formation. The intensity of TSR significantly depends on the H2O/MgSO4 mole ratio, the smaller the ratio, the stronger the oxidizing conditions. Under highly oxidizing conditions (MgSO4/hydrocarbon wt/wt 20/1 and hydrocarbon/H2O wt/wt 1/1), large amounts of H2S and CO2 are generated indicating that hydrocarbon oxidation coupled with sulfate reduction is the dominant reaction. Starting with a mixture of C21-C35 n-alkanes, these hydrocarbons are consumed totally at temperatures below the onset of hydrocarbon thermal cracking in the absence of TSR (400 ??C). Moreover, once the longer chain length hydrocarbons are oxidized, secondarily formed hydrocarbons, even methane, are oxidized to CO2. Using whole crude oils as the starting reactants, the TSR reaction dramatically lowers the stability of hydrocarbons leading to increases in gas dryness and gas/oil ratio. While their concentrations decrease, the relative distributions of n-alkanes do not change appreciably from the original composition, and consequently, are non-diagnostic for TSR. However, distinct molecular changes related to TSR are observed, Pr/n-C17 and Ph/n-C18 ratios decrease at a faster rate under TSR compared to thermal chemical alteration (TCA) alone. TSR promotes aromatization and the incorporation of sulfur and oxygen into hydrocarbons leading to a decrease in the saturate to aromatic ratio in the residual oil and in the generation of sulfur and oxygen rich pyrobitumen. These experimental findings could provide useful geochemical signatures to identify TSR in settings where TSR has occurred in natural systems. ?? 2008 Elsevier Ltd. All rights reserved.

  13. Stable sulfur isotope partitioning during simulated petroleum formation as determined by hydrous pyrolysis of Ghareb Limestone, Israel

    USGS Publications Warehouse

    Amrani, A.; Lewan, M.D.; Aizenshtat, Zeev

    2005-01-01

    Hydrous pyrolysis experiments at 200 to 365??C were carried out on a thermally immature organic-rich limestone containing Type-IIS kerogen from the Ghareb Limestone in North Negev, Israel. This work focuses on the thermal behavior of both organic and inorganic sulfur species and the partitioning of their stable sulfur isotopes among organic and inorganic phases generated during hydrous pyrolyses. Most of the sulfur in the rock (85%) is organic sulfur. The most dominant sulfur transformation is cleavage of organic-bound sulfur to form H2 S(gas). Up to 70% of this organic sulfur is released as H2S(gas) that is isotopically lighter than the sulfur in the kerogen. Organic sulfur is enriched by up to 2??? in 34S during thermal maturation compared with the initial ??34S values. The ??34S values of the three main organic fractions (kerogen, bitumen and expelled oil) are within 1??? of one another. No thermochemical sulfate reduction or sulfate formation was observed during the experiments. The early released sulfur reacted with available iron to form secondary pyrite and is the most 34S depleted phase, which is 21??? lighter than the bulk organic sulfur. The large isotopic fractionation for the early formed H2S is a result of the system not being in equilibrium. As partial pressure of H2S(gas) increases, retro reactions with the organic sulfur in the closed system may cause isotope exchange and isotopic homogenization. Part of the ??34S-enriched secondary pyrite decomposes above 300??C resulting in a corresponding decrease in the ??34S of the remaining pyrite. These results are relevant to interpreting thermal maturation processes and their effect on kerogen-oil-H2S-pyrite correlations. In particular, the use of pyrite-kerogen ??34S relations in reconstructing diagenetic conditions of thermally mature rocks is questionable because formation of secondary pyrite during thermal maturation can mask the isotopic signature and quantity of the original diagenetic pyrite. The

  14. Science Update: Inorganic Chemistry.

    ERIC Educational Resources Information Center

    Rawls, Rebecca

    1981-01-01

    Describes areas of inorganic chemistry which have changed dramatically in the past year or two, including photochemistry, electrochemistry, organometallic complexes, inorganic reaction theory, and solid state chemistry. (DS)

  15. Nitrogen Isotopic Anomalies in a Hydrous Interplanetary Dust Particle

    NASA Technical Reports Server (NTRS)

    Smith, J. B.; Dai, Z. R.; Weber, P. K.; Graham, G. A.; Hutcheon, I. D.; Bajt, S.; Ishii, H.; Bradley, J. P.

    2005-01-01

    Interplanetary dust particles (IDPs) collected in the stratosphere are the fine-grained end member (5 - 50 microns in size) of the meteoritic material available for investigation in the laboratory. IDPs are derived from either cometary or asteroidal sources. Some IDPs contain cosmically primitive materials with isotopic signatures reflecting presolar origins. Recent detailed studies using the NanoSIMS have shown there is a wide variation of isotopic signatures within individual IDPs; grains with a presolar signature have been observed surrounded by material with a solar isotopic composition. The majority of IDPs studied have been anhydrous. We report here results from integrated NanoSIMS/FIB/TEM/Synchrotron IR studies of a hydrous IDP, focused on understanding the correlations between the isotopic, mineralogical and chemical compositions of IDPs.

  16. Electrical Conductivity Measurements on Hydrous Carbonate Melts at Mantle Pressure

    NASA Astrophysics Data System (ADS)

    Sifre, D.; Gaillard, F.

    2012-04-01

    Electromagnetic methods image mantle regions in the asthenosphere with elevated conductivity (0.1 to 1 S.m-1), which constrasts with the conductivity of dry olivine (10-2 to 10-3 S.m-1). A correct interpretation of the petrological nature of the conductive mantle is critical for our understanding of mantle geodynamics because such conductive regions indicate mantle rocks with physical and chemical properties that importantly deviates from the canonical peridotites. For decades, such anomalously high mantle conductivities have been attributed to mineralogical defects associated to few tens of ppm water incorporated in olivine. Most recent experimental surveys, however, refute this hydrous olivine model. Conductive mantle regions could then reflect partial melting. The presence of melts in the Earth's mantle has long been proved by geochemical observations and experimental petrology on peridotite rocks. The requirement for melting in the asthenospheric mantle is the presence of volatile species (water, carbon dioxide, halogens). Small melt fractions are then produced by small volatile contents and they are the first liquids produced by melting magma. This study reports electrical conductivity measurements on such melts at mantle pressure and temperature. We investigated on melt chemical compositions produced by melting of peridotite that would interact with CO2-H2O and Cl. Such melts are carbonatite melts, carbonated silicate melts, hydrous carbonate melts, hydrous basalts. A new system allowing in situ electrical conductivity measurements in piston cylinder has been deployed. This design has been specifically adapted to perfom measurements on liquid samples with elevated electrical conductivities. The chemical compositions investigated are pure liquid CaCO3 and CaMg(CO3)2, to which, cloride (as salts), silicate (as basalts) and water (as brucite) have been added. Experiments have been realized at 1.5 and 2.7 GPa pressure and temperature of 1000-1700° C. Impedance

  17. Crystallization of LiAlSiO4 Glass in Hydrothermal Environments at Gigapascal Pressures-Dense Hydrous Aluminosilicates.

    PubMed

    Spektor, Kristina; Fischer, Andreas; Häussermann, Ulrich

    2016-08-15

    High-pressure hydrothermal environments can drastically reduce the kinetic constraints of phase transitions and afford high-pressure modifications of oxides at comparatively low temperatures. Under certain circumstances such environments allow access to kinetically favored phases, including hydrous ones with water incorporated as hydroxyl. We studied the crystallization of glass in the presence of a large excess of water in the pressure range of 0.25-10 GPa and at temperatures from 200 to 600 °C. The p and T quenched samples were analyzed by powder X-ray diffraction, scanning electron microscopy, and IR spectroscopy. At pressures of 0.25-2 GPa metastable zeolite Li-ABW and stable α-eucryptite are obtained at low and high temperatures, respectively, with crystal structures based on tetrahedrally coordinated Al and Si atoms. At 5 GPa a new, hydrous phase of LiAlSiO4, LiAlSiO3(OH)2 = LiAlSiO4·H2O, is produced. Its crystal structure was characterized from single-crystal X-ray diffraction data (space group P21/c, a = 9.547(3) Å, b = 14.461(5) Å, c = 5.062(2) Å, β = 104.36(1)°). The monoclinic structure resembles that of α-spodumene (LiAlSi2O6) and constitutes alternating layers of chains of corner-condensed SiO4 tetrahedra and chains of edge-sharing AlO6 octahedra. OH groups are part of the octahedral Al coordination and extend into channels provided within the SiO4 tetrahedron chain layers. At 10 GPa another hydrous phase of LiAlSiO4 with presently unknown structure is produced. The formation of hydrous forms of LiAlSiO4 shows the potential of hydrothermal environments at gigapascal pressures for creating truly new materials. In this particular case it indicates the possibility of generally accessing pyroxene-type aluminosilicates with crystallographic amounts of hydroxyl incorporated. This could also have implications to geosciences by representing a mechanism of water storage and transport in the depths of the Earth. PMID:27482770

  18. Crystallization of LiAlSiO4 Glass in Hydrothermal Environments at Gigapascal Pressures-Dense Hydrous Aluminosilicates.

    PubMed

    Spektor, Kristina; Fischer, Andreas; Häussermann, Ulrich

    2016-08-15

    High-pressure hydrothermal environments can drastically reduce the kinetic constraints of phase transitions and afford high-pressure modifications of oxides at comparatively low temperatures. Under certain circumstances such environments allow access to kinetically favored phases, including hydrous ones with water incorporated as hydroxyl. We studied the crystallization of glass in the presence of a large excess of water in the pressure range of 0.25-10 GPa and at temperatures from 200 to 600 °C. The p and T quenched samples were analyzed by powder X-ray diffraction, scanning electron microscopy, and IR spectroscopy. At pressures of 0.25-2 GPa metastable zeolite Li-ABW and stable α-eucryptite are obtained at low and high temperatures, respectively, with crystal structures based on tetrahedrally coordinated Al and Si atoms. At 5 GPa a new, hydrous phase of LiAlSiO4, LiAlSiO3(OH)2 = LiAlSiO4·H2O, is produced. Its crystal structure was characterized from single-crystal X-ray diffraction data (space group P21/c, a = 9.547(3) Å, b = 14.461(5) Å, c = 5.062(2) Å, β = 104.36(1)°). The monoclinic structure resembles that of α-spodumene (LiAlSi2O6) and constitutes alternating layers of chains of corner-condensed SiO4 tetrahedra and chains of edge-sharing AlO6 octahedra. OH groups are part of the octahedral Al coordination and extend into channels provided within the SiO4 tetrahedron chain layers. At 10 GPa another hydrous phase of LiAlSiO4 with presently unknown structure is produced. The formation of hydrous forms of LiAlSiO4 shows the potential of hydrothermal environments at gigapascal pressures for creating truly new materials. In this particular case it indicates the possibility of generally accessing pyroxene-type aluminosilicates with crystallographic amounts of hydroxyl incorporated. This could also have implications to geosciences by representing a mechanism of water storage and transport in the depths of the Earth.

  19. Hybrid organic/inorganic band-edge modulation of p-Si(111) photoelectrodes: effects of R, metal oxide, and Pt on H2 generation.

    PubMed

    Seo, Junhyeok; Kim, Hark Jin; Pekarek, Ryan T; Rose, Michael J

    2015-03-11

    The efficient generation of dihydrogen on molecularly modified p-Si(111) has remained a challenge due to the low barrier heights observed on such surfaces. The band-edge and barrier height challenge is a primary obstruction to progress in the area of integration of molecular H2 electrocatalysts with silicon photoelectrodes. In this work, we demonstrate that an optimal combination of organic passivating agent and inorganic metal oxide leads to H2 evolution at photovoltages positive of RHE. Modulation of the passivating R group [CH3 → Ph → Naph → Anth → Ph(OMe)2] improves both the band-edge position and ΔV (Vonset - VJmax). Subsequent atomic layer deposition (ALD) of Al2O3 or TiO2 along with ALD-Pt deposition results in to our knowledge the first example of a positive H2 operating potential on molecularly modified Si(111). Mott-Schottky analyses reveal that the flat-band potential of the stable Ph(OMe)2 surface approaches that of the native (but unstable) hydride-terminated surface. The series resistance is diminished by the methoxy functional groups on the phenyl unit, due to its chemical and electronic connectivity with the TiO2 layer. Overall, judicious choice of the R group in conjunction with TiO2|Pt effects H2 generation on p-Si(111) photoelectrodes (Voc = 207 ± 5.2 mV; Jsc = -21.7 mA/cm(2); ff = 0.22; ηH2 = 0.99%). These results provide a viable hybrid strategy toward the operation of catalysts on molecularly modified p-Si(111).

  20. Association Between Variants in Arsenic (+3 Oxidation State) Methyltranserase (AS3MT) and Urinary Metabolites of Inorganic Arsenic: Role of Exposure Level.

    PubMed

    Xu, Xiaofan; Drobná, Zuzana; Voruganti, V Saroja; Barron, Keri; González-Horta, Carmen; Sánchez-Ramírez, Blanca; Ballinas-Casarrubias, Lourdes; Cerón, Roberto Hernández; Morales, Damián Viniegra; Terrazas, Francisco A Baeza; Ishida, María C; Gutiérrez-Torres, Daniela S; Saunders, R Jesse; Crandell, Jamie; Fry, Rebecca C; Loomis, Dana; García-Vargas, Gonzalo G; Del Razo, Luz M; Stýblo, Miroslav; Mendez, Michelle A

    2016-09-01

    Variants in AS3MT, the gene encoding arsenic (+3 oxidation state) methyltranserase, have been shown to influence patterns of inorganic arsenic (iAs) metabolism. Several studies have suggested that capacity to metabolize iAs may vary depending on levels of iAs exposure. However, it is not known whether the influence of variants in AS3MT on iAs metabolism also vary by level of exposure. We investigated, in a population of Mexican adults exposed to drinking water As, whether associations between 7 candidate variants in AS3MT and urinary iAs metabolites were consistent with prior studies, and whether these associations varied depending on the level of exposure. Overall, associations between urinary iAs metabolites and AS3MT variants were consistent with the literature. Referent genotypes, defined as the genotype previously associated with a higher percentage of urinary dimethylated As (DMAs%), were associated with significant increases in the DMAs% and ratio of DMAs to monomethylated As (MAs), and significant reductions in MAs% and iAs%. For 3 variants, associations between genotypes and iAs metabolism were significantly stronger among subjects exposed to water As >50 versus ≤50 ppb (water As X genotype interaction P < .05). In contrast, for 1 variant (rs17881215), associations were significantly stronger at exposures ≤50 ppb. Results suggest that iAs exposure may influence the extent to which several AS3MT variants affect iAs metabolism. The variants most strongly associated with iAs metabolism-and perhaps with susceptibility to iAs-associated disease-may vary in settings with exposure level. PMID:27370415

  1. New dense hydrous magnesium silicate in the lower mantle

    NASA Astrophysics Data System (ADS)

    Nishi, M.; Irifune, T.; Tsuchiya, J.; Tange, Y.; Nishihara, Y.; Fujino, K.; Higo, Y.

    2013-12-01

    A small amount of water has been shown to strongly affect several key properties of the deep mantle, such as melting temperature, rheological property, electrical conductivity, atomic diffusivity. Recent experimental studies suggest that dense hydrous magnesium silicates (DHMS) are stable over a wide range of pressure, and therefore DHMS possibly carry water into the deep Eath's interior. The most dense form of DHMS, phase D, has been believed to be stable at least under the uppermost part of the lower mantle conditions along cold slab geotherms. However, little is known about the high pressure transformation of phase D, and the other DHMS that can be stable in the lower mantle. To determine the stability fields of the DHMS in the lower mantle, we conducted the high pressure and high temperature experiments using a large volume multianvil apparatus with sintered diamond as the second-stage anvils. In-situ X-ray diffraction measurements were also conducted in order to observe the structure of the present dense hydrous magnesium phases. The starting materials were mixture of Mg(OH)2 brucite and SiO2 silica powder. The microstructures and chemical compositions of the recovered samples were examined using a field emission-scanning electron microscope with an energy dispersive X-ray spectroscopy. We found that phase D transforms to an assemblage with a new DHMS at pressures above ~48 GPa. Phase H has a chemical composition close to MgSiH2O4. A significant amount of water is retained in the descending slabs of this new DHMS, which may be delivered to the deepest part of the lower mantle and may influence the structure and dynamics of the mantle.

  2. Formation of orthopyroxenite by reaction between peridotite and hydrous basaltic melt: an experimental study

    NASA Astrophysics Data System (ADS)

    Wang, Chunguang; Liang, Yan; Dygert, Nick; Xu, Wenliang

    2016-09-01

    The consequences of hydrous basaltic melts and peridotite interaction were examined experimentally in Au-Pd, Pt, and graphite capsules using the reaction couple method. Reactions between a hydrous basaltic andesite (4 wt% H2O) and dunite or lherzolite in an Au-Pd capsule at 1 GPa and 1200 °C produce a melt-bearing orthopyroxenite-dunite sequence. Reactions between a hydrous ferro-basalt and lherzolite in Pt or Au-Pd capsules at 0.8-2 GPa and 1250-1385 °C produce a melt-bearing orthopyroxenite-harzburgite sequence. Reactions between the ferro-basalt and lherzolite in graphite capsules (not designed to retain water) result in a melt-bearing dunite-harzburgite sequence at 1 GPa and a melt-bearing harzburgite-lherzolite sequence at 2 GPa. The orthopyroxenite from the hydrous reaction experiments has a high porosity, and it is separated by a sharp lithological interface from the dunite or harzburgite. Orthopyroxenes in the orthopyroxenite are large in size with resorbed olivine inclusions. Formation of the high-porosity orthopyroxenite in the hydrous melt-rock reaction experiments is determined by the liquidus phase relation of the interface reacting melt and reaction kinetics. Reaction between orthopyroxene-saturated hydrous melt and olivine at melt-rock interface produces orthopyroxenite. Water infiltration induces hydrous melting of the lherzolite, producing a dunite or an orthopyroxene-depleted harzburgite. Efficient diffusive exchange between the partial melt and the hydrous reacting melt promotes orthopyroxene-oversaturation around the melt-rock interfacial region. The simplified experiments reveal end-member processes for understanding the formation of orthopyroxenite in the upper mantle. The presence of orthopyroxenites in mantle samples is a strong indication of hydrous melt and peridotite interaction.

  3. Trace element mass balance in hydrous adiabatic mantle melting: The Hydrous Adiabatic Mantle Melting Simulator version 1 (HAMMS1)

    NASA Astrophysics Data System (ADS)

    Kimura, Jun-Ichi; Kawabata, Hiroshi

    2014-06-01

    numerical mass balance calculation model for the adiabatic melting of a dry to hydrous peridotite has been programmed in order to simulate the trace element compositions of basalts from mid-ocean ridges, back-arc basins, ocean islands, and large igneous provinces. The Excel spreadsheet-based calculator, Hydrous Adiabatic Mantle Melting Simulator version 1 (HAMMS1) uses (1) a thermodynamic model of fractional adiabatic melting of mantle peridotite, with (2) the parameterized experimental melting relationships of primitive to depleted mantle sources in terms of pressure, temperature, water content, and degree of partial melting. The trace element composition of the model basalt is calculated from the accumulated incremental melts within the adiabatic melting regime, with consideration for source depletion. The mineralogic mode in the primitive to depleted source mantle in adiabat is calculated using parameterized experimental results. Partition coefficients of the trace elements of mantle minerals are parameterized to melt temperature mostly from a lattice strain model and are tested using the latest compilations of experimental results. The parameters that control the composition of trace elements in the model are as follows: (1) mantle potential temperature, (2) water content in the source mantle, (3) depth of termination of adiabatic melting, and (4) source mantle depletion. HAMMS1 enables us to obtain the above controlling parameters using Monte Carlo fitting calculations and by comparing the calculated basalt compositions to primary basalt compositions. Additionally, HAMMS1 compares melting parameters with a major element model, which uses petrogenetic grids formulated from experimental results, thus providing better constraints on the source conditions.

  4. Plasma chemistry for inorganic materials

    NASA Technical Reports Server (NTRS)

    Matsumoto, O.

    1980-01-01

    Practical application of plasma chemistry to the development of inorganic materials using both low temperature and warm plasmas are summarized. Topics cover: the surface nitrification and oxidation of metals; chemical vapor deposition; formation of minute oxide particles; the composition of oxides from chloride vapor; the composition of carbides and nitrides; freezing high temperature phases by plasma arc welding and plasma jet; use of plasma in the development of a substitute for petroleum; the production of silicon for use in solar cell batteries; and insulating the inner surface of nuclear fusion reactor walls.

  5. Water Cycling in Hydrous Sulfate Sands as a Possible Analog for Dehydration of Meridiani Planum Outcrops

    NASA Astrophysics Data System (ADS)

    Chavdarian, G. V.; Sumner, D. Y.

    2007-07-01

    Cracks and fins in hydrous sulfate sands at White Sands National Monument, New Mexico, demonstrate vapor transport between the atmosphere and subsurface. A similar process may be forming cracks and fins in Meridiani outcrops in the recent past.

  6. Late Holocene hydrous mafic magmatism at the Paint Pot Crater and Callahan flows, Medicine Lake Volcano, N. California and the influence of H2O in the generation of silicic magmas

    USGS Publications Warehouse

    Kinzler, R.J.; Donnelly-Nolan, J. M.; Grove, T.L.

    2000-01-01

    This paper characterizes late Holocene basalts and basaltic andesites at Medicine Lake volcano that contain high pre-eruptive H2O contents inherited from a subduction related hydrous component in the mantle. The basaltic andesite of Paint Pot Crater and the compositionally zoned basaltic to andesitic lavas of the Callahan flow erupted approximately 1000 14C years Before Present (14C years B.P.). Petrologic, geochemical and isotopic evidence indicates that this late Holocene mafic magmatism was characterized by H2O contents of 3 to 6 wt% H2O and elevated abundances of large ion lithophile elements (LILE). These hydrous mafic inputs contrast with the preceding episodes of mafic magmatism (from 10,600 to ~3000 14C years B.P.) that was characterized by the eruption of primitive high alumina olivine tholeiite (HAOT) with low H2O (< 0.2 wt%), lower LILE abundance and different isotopic characteristics. Thus, the mantle-derived inputs into the Medicine Lake system have not always been low H2O, primitive HAOT, but have alternated between HAOT and hydrous subduction related, calc-alkaline basalt. This influx of hydrous mafic magma coincides temporally and spatially with rhyolite eruption at Glass Mountain and Little Glass Mountain. The rhyolites contain quenched magmatic inclusions similar in character to the mafic lavas at Callahan and Paint Pot Crater. The influence of H2O on fractional crystallization of hydrous mafic magma and melting of pre-existing granite crust beneath the volcano combined to produce the rhyolite. Fractionation under hydrous conditions at upper crustal pressures leads to the early crystallization of Fe-Mg silicates and the suppression of plagioclase as an early crystallizing phase. In addition, H2O lowers the saturation temperature of Fe and Mg silicates, and brings the temperature of oxide crystallization closer to the liquidus. These combined effects generate SiO2-enrichment that leads to rhyodacitic differentiated lavas. In contrast, low H2O HAOT

  7. Separation of strontium from low level radioactive waste solutions using hydrous manganese dioxide composite materials

    NASA Astrophysics Data System (ADS)

    Valsala, T. P.; Joseph, Annie; Sonar, N. L.; Sonavane, M. S.; Shah, J. G.; Raj, Kanwar; Venugopal, V.

    2010-09-01

    90Sr is one of the major isotopes present in the low level radioactive liquid waste (LLW) generated during operation of nuclear reactors and spent fuel reprocessing plants. A composite ion exchange material consisting of hydrous manganese oxide and poly methyl methacrylate (PMMA) was developed for removal of strontium from aqueous radioactive waste. The prepared composite material showed very good strontium adsorption properties in aqueous solutions. Sorption of strontium on the composite material as a function of pH, equilibration time and strontium ion concentrations were studied. The process of sorption of strontium from solution was analysed using different isotherm models like Langmuir, D-R and Freundlich. Four different error functions were employed to find out the most suitable isotherm model to represent the experimental data and it was found that Freundlich model best fits the sorption of strontium on the composite material. Analysis of the data obtained from the sorption kinetics studies showed that the data fitted better to the pseudo-second order kinetic model. Lab scale column performance study of the composite material revealed that the material could be effectively used in column operations to remove strontium from LLW solutions.

  8. Ionic liquid-based zinc oxide nanofluid for vortex assisted liquid liquid microextraction of inorganic mercury in environmental waters prior to cold vapor atomic fluorescence spectroscopic detection.

    PubMed

    Amde, Meseret; Liu, Jing-Fu; Tan, Zhi-Qiang; Bekana, Deribachew

    2016-01-01

    Zinc oxide nanofluid (ZnO-NF) based vortex assisted liquid liquid microextraction (ZnO-NF VA-LLME) was developed and employed in extraction of inorganic mercury (Hg(2+)) in environmental water samples, followed by cold vapor atomic fluorescence spectrometry (CV-AFS). Unlike other dispersive liquid liquid microextraction techniques, ZnO-NF VA-LLME is free of volatile organic solvents and dispersive solvent consumption. Analytical signals were obtained without back-extraction from the ZnO-NF phase prior to CV-AFS determination. Some essential parameters of the ZnO-NF VA-LLME and cold vapor generation such as composition and volume of the nanofluid, vortexing time, pH of the sample solution, amount of the chelating agent, ionic strength and matrix interferences have been studied. Under optimal conditions, efficient extraction of 1ng/mL of Hg(2+) in 10mL of sample solution was achieved using 50μL of ZnO-NF. The enrichment factor before dilution, detection limits and limits of quantification of the method were about 190, 0.019 and 0.064ng/mL, respectively. The intra and inter days relative standard deviations (n=8) were found to be 4.6% and 7.8%, respectively, at 1ng/mL spiking level. The accuracy of the current method was also evaluated by the analysis of certified reference materials, and the measured Hg(2+) concentration of GBW08603 (9.6ng/mL) and GBW(E)080392 (8.9ng/mL) agreed well with their certified value (10ng/mL). The method was applied to the analysis of Hg(2+) in effluent, influent, lake and river water samples, with recoveries in the range of 79.8-92.8% and 83.6-106.1% at 1ng/mL and 5ng/mL spiking levels, respectively. Overall, ZnO-NF VA-LLME is fast, simple, cost-effective and environmentally friendly and it can be employed for efficient enrichment of the analyte from various water samples.

  9. Ionic liquid-based zinc oxide nanofluid for vortex assisted liquid liquid microextraction of inorganic mercury in environmental waters prior to cold vapor atomic fluorescence spectroscopic detection.

    PubMed

    Amde, Meseret; Liu, Jing-Fu; Tan, Zhi-Qiang; Bekana, Deribachew

    2016-03-01

    Zinc oxide nanofluid (ZnO-NF) based vortex assisted liquid liquid microextraction (ZnO-NF VA-LLME) was developed and employed in extraction of inorganic mercury (Hg(2+)) in environmental water samples, followed by cold vapor atomic fluorescence spectrometry (CV-AFS). Unlike other dispersive liquid liquid microextraction techniques, ZnO-NF VA-LLME is free of volatile organic solvents and dispersive solvent consumption. Analytical signals were obtained without back-extraction from the ZnO-NF phase prior to CV-AFS determination. Some essential parameters of the ZnO-NF VA-LLME and cold vapor generation such as composition and volume of the nanofluid, vortexing time, pH of the sample solution, amount of the chelating agent, ionic strength and matrix interferences have been studied. Under optimal conditions, efficient extraction of 1ng/mL of Hg(2+) in 10mL of sample solution was achieved using 50μL of ZnO-NF. The enrichment factor before dilution, detection limits and limits of quantification of the method were about 190, 0.019 and 0.064ng/mL, respectively. The intra and inter days relative standard deviations (n=8) were found to be 4.6% and 7.8%, respectively, at 1ng/mL spiking level. The accuracy of the current method was also evaluated by the analysis of certified reference materials, and the measured Hg(2+) concentration of GBW08603 (9.6ng/mL) and GBW(E)080392 (8.9ng/mL) agreed well with their certified value (10ng/mL). The method was applied to the analysis of Hg(2+) in effluent, influent, lake and river water samples, with recoveries in the range of 79.8-92.8% and 83.6-106.1% at 1ng/mL and 5ng/mL spiking levels, respectively. Overall, ZnO-NF VA-LLME is fast, simple, cost-effective and environmentally friendly and it can be employed for efficient enrichment of the analyte from various water samples. PMID:26717850

  10. Water storage and early hydrous melting of the Martian mantle

    NASA Astrophysics Data System (ADS)

    Pommier, A.; Grove, T. L.; Charlier, B.

    2012-06-01

    We report an experimental investigation of the near-solidus phase equilibria of a water-saturated analog of the Martian mantle. Experiments were performed at low temperatures (700-920 °C) and high pressure (4-7 GPa) using multi-anvil apparatus and piston cylinder device (4 GPa). The results of this study are used to explore the role of water during early melting and chemical differentiation of Mars, and to further our understanding of the near-solidus behavior in planetary mantle compositions at high pressure. Water has a significant effect on the temperature of melting and, therefore, on accretion and subsequent differentiation processes. Experiments locate the wet solidus at ∼800 °C, and is isothermal between 4 GPa and 7 GPa. The Martian primitive mantle can store significant amounts of water in hydrous minerals stable near the solidus. Humite-group minerals and phase E represent the most abundant hydrous minerals stable in the 4-7 GPa pressure range. The amount of water that can be stored in the mantle and mobilized during melting ranges from 1 to up to 4 wt% near the wet solidus. We discuss thermal models of Mars accretion where the planet formed very rapidly and early on in solar system history. We incorporate the time constraint of Dauphas and Pourmand (2011) that Mars had accreted to 50% of its present mass in 1.8 Myr and include the effects of 26Al radioactive decay and heat supplied by rapid accretion. When accretion has reached 30% of Mars current mass (∼70% of its present size), melting starts, and extends from 100 to 720 km depth. Below this melt layer, water can still be bound in crystalline solids. The critical stage is at 50% accretion (∼80% of its size), where Mars is above the wet and dry solidi with most of its interior melted. This is earlier in the accretion process than what would be predicted from dry melting. We suggest that water may have promoted early core formation on Mars and rapidly extended melting over a large portion of Mars

  11. Hydrous Partial Melting Within the Deep Oceanic Crust

    NASA Astrophysics Data System (ADS)

    Koepke, J.; Feig, S. T.; Snow, J.

    2003-12-01

    Our knowledge on the structure, composition, and mineralogy of the in-situ lower oceanic crust (layer 3) and the mechanism how it is formed is poor. Petrological models for its generation, seismic and thermal models require an effective cooling of the deep oceanic crust. The current model implies a conductive mechanism for the cooling, and hydrothermal circulation is regarded to play a small role in transport of heat and masses in the deep oceanic crust (Wilcock, 2003). Here we demonstrate that hydrothermal circulation within the gabbroic layer starts at much higher temperatures (900° - 1000° C) as up to now believed. Water-rich fluids causes hydrous partial melting in a large scale, which is manifested by characteristic microtextures visible within many investigated rocks of all reference locations for oceanic gabbros (sampled by the Ocean Drilling Program (ODP Legs 147, 153, 176) and from the Oman ophiolite). The observed process has the potential for significant transfer of heat and masses between the upper and lower oceanic crust. The interpretation of the observed microstructures as products of hydrous partial melting is based on experimental work. Water-saturated melting experiments on a variety of natural gabbros between 900 and 1000° C at 200 MPa produced silicic melts similar in composition to oceanic plagiogranites (Koepke et al., 2003 in press). The newly formed minerals form a characteristic paragenesis consisting of plagioclase, orthopyroxene and pargasitic amphibole. In all experiments the An content of the new plagioclases is higher compared to that of the protolith, even at the lowest investigated temperature. It can be observed that olivine and clinopyroxene of the protolith react to orthopyroxene and pargasite. Very similar features can be observed in the natural gabbros. The most striking feature are zones within the plagioclase grains showing a strong enrichment in An component, often with An contents which are 20 to 25 mol% higher than those

  12. Petrological features of anhydrous and hydrous mantle xenoliths from Harrow Peaks, Antarctica

    NASA Astrophysics Data System (ADS)

    Pelorosso, Beatrice; Bonadiman, Costanza; Coltorti, Massimo; Giacomoni, Pier Paolo; Ntaflos, Theodoros

    2014-05-01

    enrichment in iron contents, accompanied (opx1 rim) by relevant depletion in Al2O3 and CaO. Primary and unmetasomatized portions of spongy cpx preserve primary residual chemical features in terms of mg#(89.19-90.87) and Al2O3(3.50-4.50 wt%), whereas TiO2 is anomalously high (0.47-0.6 wt%). In spongy and secondary cpx, effects of metasomatism at depth is evidenced by relatively higher mg# and low to very low TiO2 and Al2O3 contents, while the interaction with the host basalts univocally is testified by a coherent trend of the same elements. Sp follow the expected negative correlation between cr# [= Cr/(Cr+Al)*100 mol] and mg#, beside the strong textural evidence of matrix/melt interaction. Amphibole are pargasites (mg# 87.2-89.5) relatively homogeneous in composition with TiO2 ranging from 1.65 to 2.53 wt%. The few data so far available indicate T in the range 940 -1194 °C and relatively low condition of Δlog FMQ (-1.11; -0.25),comparable to the nearby hydrous xenolith locality of Baker Rocks. As already suggested by Bonadiman et al.(2014)the presence of amphibole do not necessarily mean high oxidation conditions. References: Bonadiman et al., (2014) CMP, in press Coltorti et. al., (2004) Lithos 75, 115-139

  13. Vibrational Sum Frequency Generation Spectroscopy Study of Hydrous Species in Soda Lime Silica Float Glass.

    PubMed

    Luo, Jiawei; Banerjee, Joy; Pantano, Carlo G; Kim, Seong H

    2016-06-21

    It is generally accepted that the mechanical properties of soda lime silica (SLS) glass can be affected by the interaction between sodium ions and hydrous species (silanol groups and water molecules) in its surface region. While the amount of these hydrous species can be estimated from hydrogen profiles and infrared spectroscopy, their chemical environment in the glass network is still not well understood. This work employed vibrational sum frequency generation (SFG) spectroscopy to investigate the chemical environment of hydrous species in the surface region of SLS float glass. SLS float glass shows sharp peaks in the OH stretching vibration region in SFG spectra, while the OH stretch peaks of glasses that do not have leachable sodium ions and the OH peaks of water molecules in condensed phases are normally broad due to fast hydrogen bonding dynamics. The hydrous species responsible for the sharp SFG peaks for the SLS float glass were found to be thermodynamically more stable than physisorbed water molecules, did not exchange with D2O, and were associated with the sodium concentration gradient in the dealkalized subsurface region. These results suggested that the hydrous species reside in static solvation shells defined by the silicate network with relatively slow hydrogen bonding dynamics, compared to physisorbed water layers on top of the glass surface. A putative radial distribution of the hydrous species within the SLS glass network was estimated based on the OH SFG spectral features, which could be compared with theoretical distributions calculated from computational simulations. PMID:27254814

  14. Vibrational Sum Frequency Generation Spectroscopy Study of Hydrous Species in Soda Lime Silica Float Glass.

    PubMed

    Luo, Jiawei; Banerjee, Joy; Pantano, Carlo G; Kim, Seong H

    2016-06-21

    It is generally accepted that the mechanical properties of soda lime silica (SLS) glass can be affected by the interaction between sodium ions and hydrous species (silanol groups and water molecules) in its surface region. While the amount of these hydrous species can be estimated from hydrogen profiles and infrared spectroscopy, their chemical environment in the glass network is still not well understood. This work employed vibrational sum frequency generation (SFG) spectroscopy to investigate the chemical environment of hydrous species in the surface region of SLS float glass. SLS float glass shows sharp peaks in the OH stretching vibration region in SFG spectra, while the OH stretch peaks of glasses that do not have leachable sodium ions and the OH peaks of water molecules in condensed phases are normally broad due to fast hydrogen bonding dynamics. The hydrous species responsible for the sharp SFG peaks for the SLS float glass were found to be thermodynamically more stable than physisorbed water molecules, did not exchange with D2O, and were associated with the sodium concentration gradient in the dealkalized subsurface region. These results suggested that the hydrous species reside in static solvation shells defined by the silicate network with relatively slow hydrogen bonding dynamics, compared to physisorbed water layers on top of the glass surface. A putative radial distribution of the hydrous species within the SLS glass network was estimated based on the OH SFG spectral features, which could be compared with theoretical distributions calculated from computational simulations.

  15. Computational studies of the geometry and electronic structure of an all-inorganic and homogeneous tetra-Ru-polyoxotungstate catalyst for water oxidation and its four subsequent one-electron oxidized forms.

    PubMed

    Quiñonero, David; Kaledin, Alexey L; Kuznetsov, Aleksey E; Geletii, Yurii V; Besson, Claire; Hill, Craig L; Musaev, Djamaladdin G

    2010-01-14

    Geometry and electronic structure of five species [{Ru(4)O(4)(OH)(2)(H(2)O)(4)}(gamma-SiW(10)O(36))(2)](10-) (1), [{Ru(4)O(4)(OH)(2)(H(2)O)(4)}(gamma-SiW(10)O(36))(2)](9-) (2), [{Ru(4)O(4)(OH)(2)(H(2)O)(4)}(gamma-SiW(10)O(36))(2)](8-) (3), [{Ru(4)O(4)(OH)(2)(H(2)O)(4)}(gamma-SiW(10)O(36))(2)](7-) (4), and [{Ru(4)O(4)(OH)(2)(H(2)O)(4)}(gamma-SiW(10)O(36))(2)](6-) (5) with different oxidation states of Ru centers were studied at the density functional and COSMO levels of theory. These species are expected to be among the possible intermediates of the recently reported 1-catalyzed water oxidation (Geletii, Y. V.; Botar, B.; Kogerler, P.; Hillesheim, D. A.; Musaev, D. G.; Hill, C. L. Angew. Chem. Int. Ed. 2008, 47, 3896-3899 and Sartorel, A.; Carraro, M.; Scorrano, G.; Zorzi, R. D.; Geremia, S.; McDaniel, N. D.; Bernhard, S.; Bonchio, M. J. Am. Chem. Soc. 2008, 130, 5006-5007). It was shown that RI-BP86 correctly describes the geometry and energy of the low-lying electronic states of compound 1, whereas the widely used B3LYP approach overestimates the energy of its high-spin states. Including the solvent and/or countercation effects into calculations improves the agreement between the calculated and experimental data. It was found that the several HOMOs and LUMOs of the studied complexes are bonding and antibonding orbitals of the [Ru(4)O(4)(OH)(2)(H(2)O)(4)](6+) core, and four subsequent one-electron oxidations of 1, leading to formation of 2, 3, 4, and 5, respectively, involve only {Ru(4)} core orbitals. In other words, catalyst instability due to ligand oxidation in the widely studied Ru-blue dimer, [(bpy)(2)(O)Ru(V)-(mu-O)-Ru(V)(O)(bpy)(2)](4+), is not operable for 1: the latter all-inorganic catalyst is predicted to be stable under water oxidation turnover conditions. The calculated HOMOs and LUMOs of all the studied species are very close in energy and exhibit a "quasi-continuum" or "nanoparticle-type" electronic structure similar to that of nanosized transition

  16. High-rate supercapacitor utilizing hydrous ruthenium dioxide nanotubes

    NASA Astrophysics Data System (ADS)

    Wu, Xu; Xiong, Wei; Chen, Yangyang; Lan, Danni; Pu, Xuli; Zeng, Yan; Gao, Hairui; Chen, Jisheng; Tong, Hua; Zhu, Zhihong

    2015-10-01

    Three-dimensional criss-crossed hydrous ruthenium dioxide (RuO2) nanotubes directly on a Ti substrate without any binder are successfully synthesized for the first time via a facile template method at a low temperature of 90 °C. A cobalt-hydroxide-carbonate nanowire array is used as the template and can be completely dissolved away during the formation process of the tubular structure. The synthetic strategy is much more cost-effective and facile than other physical/chemical methods. The obtained material possesses proper crystallinity and water content together with a distinctive structure, resulting in superior electron and ion transmission performance. When the binder-free electrode is used in a supercapacitor, it exhibits a remarkable high-rate performance with a specific capacitance of 745 F g-1 at a high current density of 32 A g-1. This represents a retention of 88.7% compared to the value of 840 F g-1 at 2 A g-1.

  17. Hydrous-Carbonaceous Meteoroids in the Hadean Aeon

    NASA Astrophysics Data System (ADS)

    Maurette, M.

    2009-12-01

    Meteoroids ˜50-200 μm in size represent the dominant mass fraction of extraterrestrial material accreted by the Earth today. About 20% of them survive as unmelted micrometeorites upon atmospheric entry, and they can be recovered from Antarctica ices and snows. Around 99% of them are related to the rare group of the most volatile-rich chondrites (˜2.5% of the meteorite falls), dominantly composed of a primitive hydrous-carbonaceous material. Micrometeorites contain a mixture of volatiles showing an elemental composition and a water isotopic composition very similar to the corresponding values measured in the contemporary Earth’s atmosphere. This surprising micrometeoritic “purity” of the Earth’s atmosphere led to an accretion equation to compute the total amount of any meteoroid species accreted by the Earth, during the first ˜100-200 Ma of the post-lunar period of the Early Heavy Bombardment of the solar system, when the mass flux of meteoroids was about one million times higher than today. This equation allows using micrometeorites and other meteoroid “ashes” as tracers of early planetary processes, including: the formation of the atmospheres of the Earth and Mars; the functioning of the Earth’s mantle, and; the formation of the prebiotic “soups” and benign climatic conditions required for the birth of life.

  18. Remote Monitoring, Inorganic Monitoring

    EPA Science Inventory

    This chapter provides an overview of applicability, amenability, and operating parameter ranges for various inorganic parameters:this chapter will also provide a compilation of existing and new online technologies for determining inorganic compounds in water samples. A wide vari...

  19. D/H isotope ratios of kerogen, bitumen, oil, and water in hydrous pyrolysis of source rocks containing kerogen types I, II, IIS, and III

    USGS Publications Warehouse

    Schimmelmann, A.; Lewan, M.D.; Wintsch, R.P.

    1999-01-01

    Immature source rock chips containing different types of kerogen (I, II, IIS, III) were artificially matured in isotopically distinct waters by hydrous pyrolysis and by pyrolysis in supercritical water. Converging isotopic trends of inorganic (water) and organic (kerogen, bitumen, oil) hydrogen with increasing time and temperature document that water-derived hydrogen is added to or exchanged with organic hydrogen, or both, during chemical reactions that take place during thermal maturation. Isotopic mass-balance calculations show that, depending on temperature (310-381??C), time (12-144 h), and source rock type, between ca. 45 and 79% of carbon-bound hydrogen in kerogen is derived from water. Estimates for bitumen and oil range slightly lower, with oil-hydrogen being least affected by water-derived hydrogen. Comparative hydrous pyrolyses of immature source rocks at 330??C for 72 h show that hydrogen in kerogen, bitumen, and expelled oil/wax ranks from most to least isotopically influenced by water-derived hydrogen in the order IIS > II ~ III > I. Pyrolysis of source rock containing type II kerogen in supercritical water at 381 ??C for 12 h yields isotopic results that are similar to those from hydrous pyrolysis at 350??C for 72 h, or 330??C for 144 h. Bulk hydrogen in kerogen contains several percent of isotopically labile hydrogen that exchanges fast and reversibly with hydrogen in water vapor at 115??C. The isotopic equilibration of labile hydrogen in kerogen with isotopic standard water vapors significantly reduces the analytical uncertainty of D/H ratios when compared with simple D/H determination of bulk hydrogen in kerogen. If extrapolation of our results from hydrous pyrolysis is permitted to natural thermal maturation at lower temperatures, we suggest that organic D/H ratios of fossil fuels in contact with formation waters are typically altered during chemical reactions, but that D/H ratios of generated hydrocarbons are subsequently little or not affected

  20. Mantle hydrous-fluid interaction with Archaean granite.

    NASA Astrophysics Data System (ADS)

    Słaby, E.; Martin, H.; Hamada, M.; Śmigielski, M.; Domonik, A.; Götze, J.; Hoefs, J.; Hałas, S.; Simon, K.; Devidal, J.-L.; Moyen, J.-F.; Jayananda, M.

    2012-04-01

    Water content/species in alkali feldspars from late Archaean Closepet igneous bodies as well as growth and re-growth textures, trace element and oxygen isotope composition have been studied (Słaby et al., 2011). Both processes growth and re-growth are deterministic, however they differ showing increasing persistency in element behaviour during interaction with fluids. The re-growth process fertilized domains and didn't change their oxygen-isotope signature. Water speciation showed persistent behaviour during heating at least up to 600oC. Carbonate crystals with mantle isotope signature are associated with the recrystallized feldspar domains. Fluid-affected domains in apatite provide evidence of halide exchange. The data testify that the observed recrystallization was a high-temperature reaction with fertilized, halide-rich H2O-CO2 mantle-derived fluids of high water activity. A wet mantle being able to generate hydrous plumes, which appear to be hotter during the Archean in comparison to the present time is supposed by Shimizu et al. (2001). Usually hot fluids, which can be strongly carbonic, precede asthenospheric mantle upwelling. They are supposed to be parental to most recognized compositions, which can be derived by their immiscible separation into saline aqueous-silicic and carbonatitic members (Klein-BenDavid et al., 2007). The aqueous fractions are halogen-rich with a significant proportion of CO2. Both admixed fractions are supposed to be fertile. The Closepet granite emplaced in a major shear zone that delimitates two different terrains. Generally such shear zones, at many places, are supposed to be rooted deep into the mantle. The drain, that favoured and controlled magma ascent and emplacement, seemed to remain efficient after granite crystallization. In the southern part of the Closepet batholiths an evidence of intensive interaction of a lower crust fluid (of high CO2 activity) is provided by the extensive charnockitization of amphibolite facies (St

  1. The redox conditions of anhydrous and hydrous xenoliths of suprasubduction and intraplate lithospheric mantle

    NASA Astrophysics Data System (ADS)

    Bonadiman, C.; Coltorti, M.

    2012-12-01

    The oxidation state of the upper mantle, its relationship with C-H-O fluids speciation and tectonic settings has been debated for decades and the various modelling have considered the prevalent role of the hydrous minerals over nominally anhydrous minerals (and the opposite) as well as the dissolution of silicate minerals (as providers of Fe3+ to the system) as directly related to water activity and oxygen fugacity. Each of these modelling has different implications for mantle rheology, seismic structure, and the evolution of the lithosphere (i.e.: Karato and Jung, 1998, Hirshmann, 2006). Upper mantle is the only part of the Earth's mantle where the oxygen fugacity can be directly measured, its values/variation being dependent on various processes such as partial melting and metasomatism often operating in time and space without solution of continuity. Recent general reviews of oxygen thermobarometry measurements (Forst & McCammon, 2008; Foley, 2011) indicate that the oxygen fugacity at the top of the upper mantle falls within ±2 log units of the fayalite-magnetite-quartz (FMQ) oxygen buffer. There is also a general consensus in considering H2O as the strongest oxidizing agent in mantle metasomatic fluids, its activity leading to the formation of amphibole and raising the mantle redox state. This contribution presents fO2 and water activity results from three spinel-bearing mantle xenolith localities and distinct geodynamic settings: Ichinomegata (Japan) amphibole-bearing peridotites entrained in calc-alkaline basalts and Cerro Fraile (South Patagonia, Argentina), mostly anhydrous lherzolites and pirossenites brought up to the surface by alkaline basalts representing fragments of sub-arc mantle and Baker Rocks, Victoria Land (Antarctica), amphibole-bearing lherzolites representing portion of intraplate subcontinental lithospheric mantle. The three mantle sectors records fO2 values in the range of -1.9 to +0.8 log units of the FQM buffer. and low to very low aH2O

  2. Hydrous pyrolysis of crude oil in gold-plated reactors

    USGS Publications Warehouse

    Curiale, J.A.; Lundegard, P.D.; Kharaka, Y.K.

    1992-01-01

    Crude oils from Iraq and California have been pyrolyzed under hydrous conditions at 200 and 300??C for time periods up to 210 days, in gold-plated reactors. Elemental (vanadium, nickel), stable isotopic (carbon), and molecular (n-alkanes, acyclic isoprenoids, steranes, terpanes and aromatic steroid hydrocarbons) analyses were made on the original and pyrolyzed oils. Various conventional crude oil maturity parameters, including 20S/(20S + 20R)-24-ethylcholestane ratios and the side-chain-length distribution of aliphatic and aromatic steroidal hydrocarbons, were measured in an effort to assess the modification of molecular maturity parameters in clay-free settings, similar to those encountered in "clean" reservoirs. Concentrations of vanadium and nickel in the Iraq oil decrease significantly and the V/(V + Ni) ratio decreases slightly, with increasing pyrolysis time/temperature. Whole oil carbon isotope ratios remain fairly constant during pyrolysis, as do hopane/sterane ratios and carbon number distribution of 5??(H),14??(H),17??(H),20R steranes. These latter three parameters are considered maturity-invariant. The ratios of short side-chain components to long side-chain components of the regular steranes [C21/(C21 + C29R)] and the triaromatic steroid hydrocarbons [C21/(C21 + C28)] vary systematically with increasing pyrolysis time, indicating that these parameters may be useful as molecular maturity parameters for crude oils in clay-free reservoir rocks. In addition, decreases in bisnorhopane/hopane ratio with increasing pyrolysis time, in a clay-free and kerogen-free environment, suggest that the distribution of these compounds is controlled by either differential thermal stabilities or preferential release from a higher-molecular weight portion of the oil. ?? 1992.

  3. Temperature-stable and optically transparent thin-film zinc oxide aerogel electrodes as model systems for 3D interpenetrating organic-inorganic heterojunction solar cells.

    PubMed

    Krumm, Michael; Pawlitzek, Fabian; Weickert, Jonas; Schmidt-Mende, Lukas; Polarz, Sebastian

    2012-12-01

    Novel, nanostructured electrode materials comprising porous ZnO films with aerogel morphology are presented. Almost any substrate including polymers, metals, or ceramics can be coated using a method that is suitable for mass production. The thin, porous films can be prepared from the wet gels via conventional drying, supercritical drying is not necessary. The filigree ZnO network is thermally very stable and exhibits sufficient electrical conductivity for advanced electronic applications. The latter was tested by realizing a highly desired architecture of organic-inorganic hybrid solar cells. After sensitizing of the ZnO with a purely organic squarine dye (SQ2), a nanostructured, interpenetrating 3D network of the inorganic semiconductor (ZnO) and organic semiconductor (P3HT) was prepared. The solar cell device was tested under illumination with AM 1.5G solar light (100 mW/cm(2)) and exhibited an energy conversion efficiency (η(eff)) of 0.69%.

  4. Density and seismic velocity of hydrous melts under crustal and upper mantle conditions

    NASA Astrophysics Data System (ADS)

    Ueki, Kenta; Iwamori, Hikaru

    2016-05-01

    We present a new model for calculating the density of hydrous silicate melts as a function of P, T, H2O concentration, and melt composition. We optimize VPr,Tr, ∂V/∂T, ∂V/∂P, ∂V2/∂T∂P, and K' of H2O end-member components in hydrous silicate melts, as well as K' of anhydrous silicate melts, using previously reported experimental results. The parameter set for H2O end-member component in silicate melt optimized in this study is internally consistent with the parameter values for the properties of anhydrous silicate melt reported by Lange and Carmichael (1987, 1990). The model calculation developed in this study reproduces the experimentally determined densities of various hydrous melts, and can be used to calculate the relationships between pressures, temperatures, and H2O concentrations of various hydrous melts from ultramafic to felsic compositions at pressures of 0-4.29 GPa. Using the new parameter set, we investigate the effects of H2O content on the seismic velocity of hydrous melts, as well as seismic velocities in partially molten regions of subduction zones. The results show that water content in silicate melt plays a key role in determining seismic velocity structure, and therefore must be taken into account when interpreting seismic tomography.

  5. U-Pb Geochronology of Hydrous Silica (Siebengebirge, Germany)

    NASA Astrophysics Data System (ADS)

    Tomaschek, Frank; Nemchin, Alexander; Geisler, Thorsten; Heuser, Alexander; Merle, Renaud

    2015-04-01

    Low-temperature, hydrous weathering eventually leads to characteristic products such as silica indurations. Elevated U concentrations and the ability of silica to maintain a closed system permits silica to be dated by the U-Pb method, which, in turn, will potentially allow constraining the timing of near-surface processes. To test the feasibility of silica U-Pb geochronology, we sampled opal and chalcedony from the Siebengebirge, Germany. This study area is situated at the terminus of the Cenozoic Lower Rhine Basin on the Rhenish Massif. The investigated samples include silicified gravels from the Mittelbachtal locality, renowned for the embedded wood opal. Structural characterization of the silica phases (Raman spectroscopy) was combined with in situ isotopic analyses, using ion microprobe and LA-ICPMS techniques. In the Siebengebirge area fluviatile sediments of Upper Oligocene age were covered by an extended trachyte tuff at around 25 Ma. Silica is known to indurate some domains within the tuff and, in particular, certain horizons within the subjacent fluviatile sediments ('Tertiärquarzite'). Cementation of the gravels occurred during at least three successive growth stages: early paracrystalline silica (opal-CT), fibrous chalcedony, and late microcrystalline quartz. It has traditionally been assumed that this silica induration reflects intense weathering, more or less synchronous with the deposition of the volcanic ashes. Results from U-Pb geochronology returned a range of discrete 206Pb-238U ages, recording a protracted silicification history. For instance, we obtained 22 ± 1 Ma for opal-CT cement from a silicified tuff, 16.6 ± 0.5 Ma for silicified wood and opal-CT cement in the fluviatile gravels, as well as 11 ± 1 Ma for texturally late chalcedony. While silicification of the sampled tuff might be contemporaneous with late-stage basalts, opaline silicification of the subjacent sediments and their wood in the Mittelbachtal clearly postdates active

  6. The density, compressibility and seismic velocity of hydrous melts at crustal and upper mantle conditions

    NASA Astrophysics Data System (ADS)

    Ueki, K.; Iwamori, H.

    2015-12-01

    Various processes of subduction zone magmatism, such as upward migration of partial melts and fractional crystallization depend on the density of the hydrous silicate melt. The density and the compressibility of the hydrous melt are key factors for the thermodynamic calculation of phase relation of the hydrous melt, and the geophysical inversion to predict physicochemical conditions of the melting region based on the seismic velocity. This study presents a new model for the calculations of the density of the hydrous silicate melts as a function of T, P, H2O content and melt composition. The Birch-Murnaghan equation is used for the equation of state. We compile the experimentally determined densities of various hydrous melts, and optimize the partial molar volume, compressibility, thermal expansibility and its pressure derivative, and K' of the H2O component in the silicate melt. P-T ranges of the calibration database are 0.48-4.29 GPa and 1033-2073 K. As such, this model covers the P-T ranges of the entire melting region of the subduction zone. Parameter set provided by Lange and Carmichael [1990] is used for the partial molar volume and KT value of the anhydrous silicate melt. K' of anhydrous melt is newly parameterized as a function of SiO2 content. The new model accurately reproduces the experimentally determined density variations of various hydrous melts from basalt to rhyolite. Our result shows that the hydrous melt is more compressive and less dense than the anhydrous melt; with the 5 wt% of H2O in melt, density and KT decrease by ~10% and ~30% from those of the anhydrous melt, respectively. For the application of the model, we calculated the P-wave velocity of the hydrous melt. With the 5 wt% of H2O, P-wave velocity of the silicate melt decreases by >10%. Based on the melt P-wave velocity, we demonstrate the effect of the melt H2O content on the seismic velocity of the partially molten zone of the subduction zone.

  7. Thermodynamics and Kinetics of Sulfide Oxidation by Oxygen: A Look at Inorganically Controlled Reactions and Biologically Mediated Processes in the Environment

    PubMed Central

    Luther, George W.; Findlay, Alyssa J.; MacDonald, Daniel J.; Owings, Shannon M.; Hanson, Thomas E.; Beinart, Roxanne A.; Girguis, Peter R.

    2011-01-01

    The thermodynamics for the first electron transfer step for sulfide and oxygen indicates that the reaction is unfavorable as unstable superoxide and bisulfide radical ions would need to be produced. However, a two-electron transfer is favorable as stable S(0) and peroxide would be formed, but the partially filled orbitals in oxygen that accept electrons prevent rapid kinetics. Abiotic sulfide oxidation kinetics improve when reduced iron and/or manganese are oxidized by oxygen to form oxidized metals which in turn oxidize sulfide. Biological sulfur oxidation relies on enzymes that have evolved to overcome these kinetic constraints to affect rapid sulfide oxidation. Here we review the available thermodynamic and kinetic data for H2S and HS• as well as O2, reactive oxygen species, nitrate, nitrite, and NOx species. We also present new kinetic data for abiotic sulfide oxidation with oxygen in trace metal clean solutions that constrain abiotic rates of sulfide oxidation in metal free solution and agree with the kinetic and thermodynamic calculations. Moreover, we present experimental data that give insight on rates of chemolithotrophic and photolithotrophic sulfide oxidation in the environment. We demonstrate that both anaerobic photolithotrophic and aerobic chemolithotrophic sulfide oxidation rates are three or more orders of magnitude higher than abiotic rates suggesting that in most environments biotic sulfide oxidation rates will far exceed abiotic rates due to the thermodynamic and kinetic constraints discussed in the first section of the paper. Such data reshape our thinking about the biotic and abiotic contributions to sulfide oxidation in the environment. PMID:21833317

  8. Origin of hydrous alkali feldspar-silica intergrowth in spherulites from intra-plate A2-type rhyolites at the Jabal Shama, Saudi Arabia

    NASA Astrophysics Data System (ADS)

    Surour, Adel A.; El-Nisr, Said A.; Bakhsh, Rami A.

    2016-03-01

    Miocene rhyolites (19.2 ± 0.9 Ma) at the Jabal Shama in western Saudi Arabia represent an example of rift-related silicic volcanism that took place during the formation of the Red Sea. They mostly consist of tuffaceous varieties with distinct flow banding, and pea-sized spherulites, obsidian and perlitized rhyolite tuffs. Although they have the geochemical signature of A2-type rhyolites, these silicic rocks are not typically alkaline but alkali-calcic to calc-alkaline. They developed in a within-plate regime and possibly derived from a recycled mafic subducted slab in depleted sub-continental mantle beneath the western Arabian plate. The Jabal Shama rhyolites are younger in age than their Miocene counterparts in Yemen and Ethiopia. The Jabal Shama spherulites consist of hydrous alkali feldspar-silica radial intergrowths with an occasional brown glass nucleus. Carbonate- and glass-free spherulites give up to 4.45 wt% L.O.I. The hydrous nature of these silicates and the absence of magnetite in the spherulites is a strong indication of oxidizing conditions. The spherulites contain hydrous feldspars with up to ∼6 wt% H2O, and they develop by diffusion and devitrification of glass in the rhyolite tuff at ∼800 °C. Owing to higher undercooling due to supersaturation, the radial hydrous phases within spherulites might grow faster and led to coagulation. The polygonal contacts between spherulites and the ∼120° dihedral angle suggest solid-state modification and recrystallization as the process of devitrification proceeds as low as ∼300 °C. The sum of FeO + MgO is positively correlated with total alkalies along with magnetite oxidation in the matrix to Fe-oxyhydroxides, and to the incorporation of OH- into silicates within the spehrulites themselves. Structural H2O in glass of the Jabal Shama perlite (obsidian) is considerable (∼9-12 wt%) with 3.72-5.6 wt% L.O.I. of the whole-rock. The presence of deleterious silica impurities would lower the ore grade due to

  9. FORUM: Bioinspired Heme, Heme/non-heme Diiron, Heme/copper and Inorganic NOx Chemistry: ·NO(g) Oxidation, Peroxynitrite-Metal Chemistry and ·NO(g) Reductive Coupling

    PubMed Central

    Schopfer, Mark P.; Wang, Jun; Karlin, Kenneth D.

    2010-01-01

    The focus of this Forum review highlights work from our own laboratories and those of others in the area of biochemical and biologically inspired inorganic chemistry dealing with nitric oxide (nitrogen monoxide, ·NO(g)) and its biological roles and reactions. The latter focus is on (i) oxidation of ·NO(g) to nitrate by nitric oxide dioxygenases (NOD’s), and (ii) reductive coupling of two molecules of ·NO(g) to give N2O(g). In the former case, NOD’s are described and the highlighting of possible peroxynitrite-heme intermediates and consequences of this are given by discussion of recent works with myoglobin and a synthetic heme model system for NOD action. Summaries of recent copper complex chemistries with ·NO(g) and O2(g) leading to peroxynitrite species are given. The coverage of biological reductive coupling of ·NO(g) deals with bacterial nitric oxide reductases (NOR’s) with heme/non-heme diiron active sites, and on heme/Cu oxidases such as cytochrome c oxidase which can mediate the same chemistry. Recent designed protein and synthetic model compound (heme/non-heme diiron or heme/copper) as functional mimics are discussed in some detail. We also highlight examples from the chemical literature, not necessarily involving biologically relevant metal ions, which describe the oxidation of ·NO(g) to nitrate (or nitrite) and possible peroxynitrite intermediates, or reductive coupling of ·NO(g) to give nitrous oxide. PMID:20666386

  10. Method for plating with metal oxides

    DOEpatents

    Silver, G.L.; Martin, F.S.

    1994-08-23

    A method is disclosed of plating hydrous metal oxides on at least one substrate, which method is indifferent to the electrochemical properties of the substrate, and comprises reacting metallic ions in aqueous solution with an appropriate oxidizing agent such as sodium hypochlorite or calcium sulfite with oxygen under suitable conditions of pH and concentration such that oxidation and precipitation of metal oxide are sufficiently slow to allow satisfactory plating of metal oxide on the substrate. 1 fig.

  11. Method for plating with metal oxides

    SciTech Connect

    Silver, Gary L.; Martin, Frank S.

    1994-08-23

    A method of plating hydrous metal oxides on at least one substrate, which method is indifferent to the electrochemical properties of the substrate, and comprises reacting metallic ions in aqueous solution with an appropriate oxidizing agent such as sodium hypochlorite or calcium sulfite with oxygen under suitable conditions of pH and concentration such that oxidation and precipitation of metal oxide are sufficiently slow to allow satisfactory plating of metal oxide on the substrate.

  12. Fabricating porous materials using interpenetrating inorganic-organic composite gels

    DOEpatents

    Seo, Dong-Kyun; Volosin, Alex

    2016-06-14

    Porous materials are fabricated using interpenetrating inorganic-organic composite gels. A mixture or precursor solution including an inorganic gel precursor, an organic polymer gel precursor, and a solvent is treated to form an inorganic wet gel including the organic polymer gel precursor and the solvent. The inorganic wet gel is then treated to form a composite wet gel including an organic polymer network in the body of the inorganic wet gel, producing an interpenetrating inorganic-organic composite gel. The composite wet gel is dried to form a composite material including the organic polymer network and an inorganic network component. The composite material can be treated further to form a porous composite material, a porous polymer or polymer composite, a porous metal oxide, and other porous materials.

  13. Inorganic Nanomaterials as Carriers for Drug Delivery.

    PubMed

    Chen, Shizhu; Hao, Xiaohong; Liang, Xingjie; Zhang, Qun; Zhang, Cuimiao; Zhou, Guoqiang; Shen, Shigang; Jia, Guang; Zhang, Jinchao

    2016-01-01

    For safe and effective therapy, drugs must be delivered efficiently and with minimal systemic side effects. Nanostructured drug carriers enable the delivery of small-molecule drugs as well as nucleic acids and proteins. Inorganic nanomaterials are ideal for drug delivery platforms due to their unique physicochemical properties, such as facile preparation, good storage stability and biocompatibility. Many inorganic nanostructure-based drug delivery platforms have been prepared. Although there are still many obstacles to overcome, significant advances have been made in recent years. This review focuses on the status and development of inorganic nanostructures, including silica, quantum dots, gold, carbon-based and magnetic iron oxide-based nanostructures, as carriers for chemical and biological drugs. We specifically highlight the extensive use of these inorganic drug carriers for cancer therapy. Finally, we discuss the most important areas in the field that urgently require further study. PMID:27301169

  14. Inorganic contents of peats

    SciTech Connect

    Raymond, R. Jr.; Bish, D.L.; Cohen, A.D.

    1988-02-01

    Peat, the precursor of coal, is composed primarily of plant components and secondarily of inorganic matter derived from a variety of sources. The elemental, mineralogic, and petrographic composition of a peat is controlled by a combination of both its botanical and depositional environment. Inorganic contents of peats can vary greatly between geographically separated peat bogs as well as vertially and horizontally within an individual bog. Predicting the form and distribution of inorganic matter in a coal deposit requires understanding the distribution and preservation of inorganic matter in peat-forming environments and diagenetic alterations affecting such material during late-stage peatification and coalification processes. 43 refs., 4 figs., 3 tabs.

  15. Selective inorganic thin films

    SciTech Connect

    Phillips, M.L.F.; Pohl, P.I.; Brinker, C.J.

    1997-04-01

    Separating light gases using membranes is a technology area for which there exists opportunities for significant energy savings. Examples of industrial needs for gas separation include hydrogen recovery, natural gas purification, and dehydration. A membrane capable of separating H{sub 2} from other gases at high temperatures could recover hydrogen from refinery waste streams, and facilitate catalytic dehydrogenation and the water gas shift (CO + H{sub 2}O {yields} H{sub 2} + CO{sub 2}) reaction. Natural gas purification requires separating CH{sub 4} from mixtures with CO{sub 2}, H{sub 2}S, H{sub 2}O, and higher alkanes. A dehydrating membrane would remove water vapor from gas streams in which water is a byproduct or a contaminant, such as refrigeration systems. Molecular sieve films offer the possibility of performing separations involving hydrogen, natural gas constituents, and water vapor at elevated temperatures with very high separation factors. It is in applications such as these that the authors expect inorganic molecular sieve membranes to compete most effectively with current gas separation technologies. Cryogenic separations are very energy intensive. Polymer membranes do not have the thermal stability appropriate for high temperature hydrogen recovery, and tend to swell in the presence of hydrocarbon natural gas constituents. The authors goal is to develop a family of microporous oxide films that offer permeability and selectivity exceeding those of polymer membranes, allowing gas membranes to compete with cryogenic and adsorption technologies for large-scale gas separation applications.

  16. Melting the hydrous, subarc mantle: the origin of primitive andesites

    NASA Astrophysics Data System (ADS)

    Mitchell, Alexandra L.; Grove, Timothy L.

    2015-08-01

    This experimental study is the first comprehensive investigation of the melting behavior of an olivine + orthopyroxene ± spinel—bearing fertile mantle (FM) composition as a function of variable pressure and water content. The fertile composition was enriched with a metasomatic slab component of ≤0.5 % alkalis and investigated from 1135 to 1470 °C at 1.0-2.0 GPa. A depleted lherzolite with 0.4 % alkali addition was also studied from 1225 to 1240 °C at 1.2 GPa. Melts of both compositions were water-undersaturated: fertile lherzolite melts contained 0-6.4 wt% H2O, and depleted lherzolite melts contained ~2.5 wt% H2O. H2O contents of experimental glasses are measured using electron microprobe, secondary ion mass spectrometry, and synchrotron-source reflection Fourier transform infrared spectroscopy, a novel technique for analyzing H2O in petrologic experiments. Using this new dataset in conjunction with results from previous hydrous experimental studies, a thermobarometer and a hygrometer-thermometer are presented to determine the conditions under which primitive lavas were last in equilibration with the mantle. These predictive models are functions of H2O content and pressure, respectively. A predictive melting model is also presented that calculates melt compositions in equilibrium with an olivine + orthopyroxene ± spinel residual assemblage (harzburgite). This model quantitatively predicts the following influences of H2O on mantle lherzolite melting: (1) As melting pressure increases, melt compositions become more olivine-normative, (2) as melting extent increases, melt compositions become depleted in the normative plagioclase component, and (3) as melt H2O content increases, melts become more quartz-normative. Natural high-Mg# [molar Mg/(Mg + Fe2+)], high-MgO basaltic andesite and andesite lavas—or primitive andesites (PAs)—contain high SiO2 contents at mantle-equilibrated Mg#s. Their compositional characteristics cannot be readily explained by melting

  17. Magnetite in Stardust Terminal Grains: Evidence for Hydrous Alteration in the Wild2 Parent Body

    NASA Astrophysics Data System (ADS)

    Bridges, J. C.; Hicks, L. J.; MacArthur, J. L.; Price, M. C.; Burchell, M. J.; Franchi, I. A.; Gurman, S. J.

    2015-10-01

    We use synchrotron X-ray Diffraction and other techniques to show the presence of magnetite in terminal grains from Stardust cometary tracks. This suggests that the parent body of Comet Wild2 underwent hydrous alteration, and gives further evidence for the varied mineralogical history of this early Solar System body from the Outer Solar System.

  18. Hydrous mineral dehydration around heat-generating nuclear waste in bedded salt formations.

    PubMed

    Jordan, Amy B; Boukhalfa, Hakim; Caporuscio, Florie A; Robinson, Bruce A; Stauffer, Philip H

    2015-06-01

    Heat-generating nuclear waste disposal in bedded salt during the first two years after waste emplacement is explored using numerical simulations tied to experiments of hydrous mineral dehydration. Heating impure salt samples to temperatures of 265 °C can release over 20% by mass of hydrous minerals as water. Three steps in a series of dehydration reactions are measured (65, 110, and 265 °C), and water loss associated with each step is averaged from experimental data into a water source model. Simulations using this dehydration model are used to predict temperature, moisture, and porosity after heating by 750-W waste canisters, assuming hydrous mineral mass fractions from 0 to 10%. The formation of a three-phase heat pipe (with counter-circulation of vapor and brine) occurs as water vapor is driven away from the heat source, condenses, and flows back toward the heat source, leading to changes in porosity, permeability, temperature, saturation, and thermal conductivity of the backfill salt surrounding the waste canisters. Heat pipe formation depends on temperature, moisture availability, and mobility. In certain cases, dehydration of hydrous minerals provides sufficient extra moisture to push the system into a sustained heat pipe, where simulations neglecting this process do not.

  19. SEM Observation of Hydrous Superabsorbent Polymer Pretreated with Room-Temperature Ionic Liquids

    PubMed Central

    Tsuda, Tetsuya; Mochizuki, Eiko; Kishida, Shoko; Iwasaki, Kazuki; Tsunashima, Katsuhiko; Kuwabata, Susumu

    2014-01-01

    Room-temperature ionic liquid (RTIL), which is a liquid salt at or below room temperature, shows peculiar physicochemical properties such as negligible vapor pressure and relatively-high ionic conductivity. In this investigation, we used six types of RTILs as a liquid material in the pretreatment process for scanning electron microscope (SEM) observation of hydrous superabsorbent polymer (SAP) particles. Very clear SEM images of the hydrous SAP particles were obtained if the neat RTILs were used for the pretreatment process. Of them, tri-n-butylmethylphosphonium dimethylphosphate ([P4, 4, 4, 1][DMP]) provided the best result. On the other hand, the surface morphology of the hydrous SAP particles pretreated with 1-ethyl-3-methylimidazolium tetrafluoroborate ([C2mim][BF4]) and 1-butyl-3-methylimidazolium tetrafluoroborate ([C4mim][BF4]) was damaged. The results of SEM observation and thermogravimetry analysis of the hydrous SAP pretreated with the RTILs strongly suggested that most water in the SAP particles are replaced with RTIL during the pretreatment process. PMID:24621609

  20. The Effect of Disorder on Hydrous Mineral Stability at High Pressure

    NASA Astrophysics Data System (ADS)

    Rytel, A. L.; Pigott, J. S.; Panero, W. R.

    2014-12-01

    The water storage capacity in the Earth's deep interior and its transport between reservoirs is in part dependent upon the stability of high-pressure phases of hydrous minerals. Prediction of mineral stability in the Earth's mantle is dependent upon accurately calculating the Gibbs free energy of each phase as a function of pressure, temperature, and composition. Contributions from crystallographic disorder to the configurational entropy can extend the stability field of minerals at high temperatures. In certain hydrous and anhydrous aluminum and magnesium silicates such as ringwoodite, some degree of disorder is favored at mantle pressure and temperature conditions. This study constrains the water storage capacity of the mantle by examining the effects of cation disorder on the structure and energetics of hydrous and anhydrous aluminum and magnesium silicates (kyanite, topaz-OH, phase egg, phase D, and δ-AlOOH) as a function of Si and Al coordination. We present the energetics of disorder at mantle pressure and temperature conditions from static lattice energy minimizations using interatomic potentials and complementary first-principles calculations coupled with modeling of configurational entropy. This work assesses the applicability of the aluminum avoidance principle in high-pressure hydrous aluminosilicates.

  1. Low-Mr hydrocarbons generated during hydrous and dry pyrolysis of kerogen.

    PubMed

    Tannenbaum, E; Kaplan, I R

    1985-10-24

    The validity of applying laboratory pyrolysis experiments to simulating the maturation of organic matter in sedimentary basins has been vigorously debated. We report here results from the generation of hydrocarbons of low relative molecular mass (Mr) in both hydrous and dry pyrolysis. A principal difference is that under dry conditions in the presence of montmorillonite, catalysis occurs with respect to generation of low-Mr hydrocarbons but no such effect is evident for hydrous conditions, probably because of a reduction in the clay's acidity. In addition, olefins which were previously reported as not being present in the products of hydrous pyrolyses were found to be produced in the C2-C6 range in comparable amounts under both hydrous and dry pyrolyses at 300 degrees C and may form in the course of kerogen catagenesis in nature but disappear with geologic time due to their instability. These studies have relevance to understanding the interactions between kerogen and minerals in sedimentary rocks and to processes in the formation of natural gas.

  2. The Decisive but Quite Limited Role of Hydrous and Carbonaceous Minerals During Subduction - an Opinion

    NASA Astrophysics Data System (ADS)

    Schmidt, M. W.

    2005-12-01

    Subduction is interesting because it enables geochemical exchange between the subducting crust and the Earth's mantle. Such exchange occurs through two processes: element transport in a mobile phase which moves between the reservoirs or mechanical mixture of the reminder of devolatilization with the mantle. After initial expulsion of pore fluids and decomposition of clay minerals, hydrous and carbonaceous phases are fundamental for the production of a fluid, melt or supercritical liquid within the subducting lithosphere. The role and contribution of the different hydrous minerals can be quantified when superimposing thermo-mechanical models and phase diagrams (e.g. Connolly 2005, EPSL). Chlorite, amphibole, epidote/zoisite, lawsonite and chloritoid are the most important hydrous minerals in mafic and pelagic lithologies, this list is appended by the role of phengite in defining melting conditions in any lithology with significant K2O. In some subduction zones, carbonates may be omnipresent, nevertheless, dolomite and magnesite are extremely refractory and XCO2 in the fluid is generally low, thus making it difficult to mobilize CO2 at typical subduction zone conditions. With regard to the mantle, the contributions and conditions for serpentine, clinohumite, chondrodite, phase A and phase E are reviewed. Whereas the major element geochemistry as well as fluid and melt production are clearly dominated by hydrous phases, this is only valid to a much diminished extent for trace elements. Many of the major hydrous phases are quite limited as residual phases, in particular, because trace element budgets are established in an essentially diffusion-free (low temperature) environment: distribution coefficients between hydrous and mobile phases are important, but fluids equilibrate only with the (mostly unhydrous) phases formed anew during hydrous phase breakdown, an aspect that is generally ignored in trace element modeling. Furthermore, fluids originating from lower parts

  3. Comparison of artificial maturation of lignite in hydrous and nonhydrous conditions

    USGS Publications Warehouse

    Behar, F.; Lewan, M.D.; Lorant, F.; Vandenbroucke, M.

    2003-01-01

    The objectives of the study are to compare product compositions and yields generated from lignite artificially matured by open nonhydrous pyrolysis, closed nonhydrous pyrolysis, and hydrous pyrolysis. The pyrolysis products were fractionated into CO2, H2O, CH4, C2-C5, C8-C14, C14+ saturates, C14+ aromatics and NSOs (resins+asphaltenes). All three methods generated high and similar quantities of water during pyrolysis that ranged between 14.6 and 15.2 wt.% of the original lignite. As a result of this high water content generated by the lignite, the experiments with no added water are referred to as nonhydrous rather than anhydrous. Rock-Eval pyrolysis and elemental analyses were conducted on the recovered lignite after solvent extraction to determine their residual hydrocarbon generation potential and to plot their position in a van Krevelen diagram, respectively. Residual lignite from the closed nonhydrous and hydrous experiments showed relationships between vitrinite reflectance (%Ro) values and atomic H/C ratios that occurred within the fields observed for natural maturation of coal. Although no significant differences in the atomic H/C ratios were observed between closed nonhydrous and hydrous pyrolysis, the vitrinite reflectance values were on the average 0.2% Ro lower in the residual lignite from the nonhydrous experiments. The remaining hydrocarbon generation potential as determined by Rock-Eval pyrolysis of the residual lignite showed that the nonhydrous residuals had on the average 16 mg more hydrocarbon potential per gram of original lignite than the hydrous residuals. This suggests there is a better release of the pyrolysis products from the lignite network in the hydrous experiments once generation occurs. For gas generation, at maximum yields, open nonhydrous pyrolysis generates the most hydrocarbon gas (21.0 mg/g original lignite), which is 20% more than closed nonhydrous pyrolysis and 29% more than hydrous pyrolysis. Closed nonhydrous pyrolysis

  4. Comparison of petroleum generation kinetics by isothermal hydrous and nonisothermal open-system pyrolysis

    USGS Publications Warehouse

    Lewan, M.D.; Ruble, T.E.

    2002-01-01

    This study compares kinetic parameters determined by open-system pyrolysis and hydrous pyrolysis using aliquots of source rocks containing different kerogen types. Kinetic parameters derived from these two pyrolysis methods not only differ in the conditions employed and products generated, but also in the derivation of the kinetic parameters (i.e., isothermal linear regression and non-isothermal nonlinear regression). Results of this comparative study show that there is no correlation between kinetic parameters derived from hydrous pyrolysis and open-system pyrolysis. Hydrous-pyrolysis kinetic parameters determine narrow oil windows that occur over a wide range of temperatures and depths depending in part on the organic-sulfur content of the original kerogen. Conversely, open-system kinetic parameters determine broad oil windows that show no significant differences with kerogen types or their organic-sulfur contents. Comparisons of the kinetic parameters in a hypothetical thermal-burial history (2.5 ??C/my) show open-system kinetic parameters significantly underestimate the extent and timing of oil generation for Type-US kerogen and significantly overestimate the extent and timing of petroleum formation for Type-I kerogen compared to hydrous pyrolysis kinetic parameters. These hypothetical differences determined by the kinetic parameters are supported by natural thermal-burial histories for the Naokelekan source rock (Type-IIS kerogen) in the Zagros basin of Iraq and for the Green River Formation (Type-I kerogen) in the Uinta basin of Utah. Differences in extent and timing of oil generation determined by open-system pyrolysis and hydrous pyrolysis can be attributed to the former not adequately simulating natural oil generation conditions, products, and mechanisms.

  5. Effect of thermal maturation on the K-Ar, Rb-Sr and REE systematics of an organic-rich New Albany Shale as determined by hydrous pyrolysis

    USGS Publications Warehouse

    Clauer, Norbert; Chaudhuri, Sambhudas; Lewan, M.D.; Toulkeridis, T.

    2006-01-01

    Hydrous-pyrolysis experiments were conducted on an organic-rich Devonian-Mississippian shale, which was also leached by dilute HCl before and after pyrolysis, to identify and quantify the induced chemical and isotopic changes in the rock. The experiments significantly affect the organic-mineral organization, which plays an important role in natural interactions during diagenetic hydrocarbon maturation in source rocks. They produce 10.5% of volatiles and the amount of HCl leachables almost doubles from about 6% to 11%. The Rb-Sr and K-Ar data are significantly modified, but not just by removal of radiogenic 40Ar and 87Sr, as described in many studies of natural samples at similar thermal and hydrous conditions. The determining reactions relate to alteration of the organic matter marked by a significant change in the heavy REEs in the HCl leachate after pyrolysis, underlining the potential effects of acidic fluids in natural environments. Pyrolysis induces also release from organics of some Sr with a very low 87Sr/86Sr ratio, as well as part of U. Both seem to have been volatilised during the experiment, whereas other metals such as Pb, Th and part of U appear to have been transferred from soluble phases into stable (silicate?) components. Increase of the K2O and radiogenic 40Ar contents of the silicate minerals after pyrolysis is explained by removal of other elements that could only be volatilised, as the system remains strictly closed during the experiment. The observed increase in radiogenic 40Ar implies that it was not preferentially released as a volatile gas phase when escaping the altered mineral phases. It had to be re-incorporated into newly-formed soluble phases, which is opposite to the general knowledge about the behavior of Ar in supergene natural environments. Because of the strictly closed-system conditions, hydrous-pyrolysis experiments allow to better identify and even quantify the geochemical aspects of organic-inorganic interactions, such as

  6. Hydrous carbonates on Mars?: evidence from Mariner 6/7 infrared spectrometer and ground-based telescopic spectra

    USGS Publications Warehouse

    Calvin, W.M.; King, T.V.V.; Clark, R.N.

    1994-01-01

    Absorption features at 2.28 and 5.4 ??m identified in Mariner 6/7 infrared spectrometer and terrestrial telescopic spectra are consistent with the spectra of hydrous magnesium carbonates such as hydromagnesite and artinite. Spectral characteristics of these hydrous carbonates are different from those of the anhydrous carbonates, as the former do not have the strong spectral features typically associated with anhydrous carbonates such as calcite and siderite. Although the spectroscopic evidence for anhydrous carbonates is scant, the possible presence of hydrous carbonates provides an appealing mechanism for the existence of carbonates on Mars. -from Authors

  7. Chalcophile element partitioning between sulfide phases and hydrous mantle melt: Applications to mantle melting and the formation of ore deposits

    NASA Astrophysics Data System (ADS)

    Li, Yuan

    2014-11-01

    Understanding the geochemical behavior of chalcophile elements in magmatic processes is hindered by the limited partition coefficients between sulfide phases and silicate melt, in particular at conditions relevant to partial melting of the hydrated, metasomatized upper mantle. In this study, the partitioning of elements Co, Ni, Cu, Zn, As, Mo, Ag, and Pb between sulfide liquid, monosulfide solid solution (MSS), and hydrous mantle melt has been investigated at 1200 °C/1.5 GPa and oxygen fugacity ranging from FMQ-2 to FMQ+1 in a piston-cylinder apparatus. The determined partition coefficients between sulfide liquid and hydrous mantle melt are: 750-1500 for Cu; 600-1200 for Ni; 35-42 for Co; 35-53 for Pb; and 1-2 for Zn, As, and Mo. The partition coefficients between MSS and hydrous mantle melt are: 380-500 for Cu; 520-750 for Ni; ∼50 for Co; <0.5 for Zn; 0.3-6 for Pb; 0.1-2 for As; 1-2 for Mo; and >34 for Ag. The variation of the data is primarily due to differences in oxygen fugacity. These partitioning data in conjunction with previous data are applied to partial melting of the upper mantle and the formation of magmatic-hydrothermal Cu-Au deposits and magmatic sulfide deposits. I show that the metasomatized arc mantle may no longer contain sulfide after >10-14% melt extraction but is still capable of producing the Cu concentrations in the primitive arc basalts, and that the comparable Cu concentrations in primitive arc basalts and in MORB do not necessarily imply similar oxidation states in their source regions. Previous models proposed for producing Cu- and/or Au-rich magmas have been reassessed, with the conclusions summarized as follows. (1) Partial melting of the oxidized (fO2 > FMQ), metasomatized arc mantle with sulfide exhaustion at degrees >10-14% may not generate Cu-rich, primitive arc basalts. (2) Partial melting of sulfide-bearing cumulates in the root of thickened lower continental crust or lithospheric mantle does not typically generate Cu- and

  8. New composites of nanoparticle Cu (I) oxide and titania in a novel inorganic polymer (geopolymer) matrix for destruction of dyes and hazardous organic pollutants.

    PubMed

    Falah, Mahroo; MacKenzie, Kenneth J D; Knibbe, Ruth; Page, Samuel J; Hanna, John V

    2016-11-15

    New photoactive composites to efficiently remove organic dyes from water are reported. These consist of Cu2O/TiO2 nanoparticles in a novel inorganic geopolymer matrix modified by a large tertiary ammonium species (cetyltrimethylammonium bromide, CTAB) whose presence in the matrix is demonstrated by FTIR spectroscopy. The CTAB does not disrupt the tetrahedral geopolymer structural silica and alumina units as demonstrated by (29)Si and (27)Al MAS NMR spectroscopy. SEM/EDS, TEM and BET measurements suggest that the Cu2O/TiO2 nanoparticles are homogenously distributed on the surface and within the geopolymer pores. The mechanism of removal of methylene blue (MB) dye from solution consists of a combination of adsorption (under dark conditions) and photodegradation (under UV radiation). MB adsorption in the dark follows pseudo second-order kinetics and is described by Freundlich-Langmuir type isotherms. The performance of the CTAB-modified geopolymer based composites is superior to composites based on unmodified geopolymer hosts, the most effective composite containing 5wt% Cu2O/TiO2 in a CTAB-modified geopolymer host. These composites constitute a new class of materials with excellent potential in environmental protection applications.

  9. Experiments on phase equilibria in hydrous tholeiitic systems: implications for the genesis of oceanic plagiogranites

    NASA Astrophysics Data System (ADS)

    Koepke, J.; Berndt, J.; Feig, S. T.

    2003-04-01

    For the genesis of oceanic plagiogranites at mid-ocean spreading systems, two models are under discussion: (1) Late-stage differentiation of a MORB-type melt and (2) partial melting of pre-existing gabbros within high-temperature shear zones. In this study, we have applied recent experimental data of the experimental lab in Hannover to the plagiogranite petrogenesis in order to test both models. The role of water during the genesis of these rocks (presence of amphibole as mafic phase in natural plagiogranites) was assessed by including water to the systems. Crystallization experiments were performed in a MORB system doped with different water contents at different redox conditions at 200 MPa (Berndt, 2002), and hydrous partial melting experiments were performed at 200 MPa on typical oceanic gabbros (Feig et al., this volume). For the experiments we have used an internally heated pressure vessel for high temperatures (up to 1250°C) equipped with a rapid-quench system and a hydrogen membrane for controlling the oxygen fugacity. Liquid lines of descent obtained via crystallization experiments are mainly controlled by oxygen fugacity and only to a little extent by water activity. SiO2-rich residual melts can be obtained under both oxidizing and reducing redox condition at low temperatures, but at least one fractionation step is required to reach high-silicic plagiogranites (SiO2 > 70 wt%). The partial melting of typical oceanic gabbro leads at low temperatures also to plagiogranitic melts. At 940°C, the normalized SiO2 contents of the experimental melts of the three investigated systems range between 60 and 61 wt%, and at 900°C from 63 and 68 wt%. These melts coexist with orthopyroxene, amphibole, plagioclase and in one sample also with olivine. The experimental melt compositions are compared with those of natural plagiogranites of different tectonic settings and show in general a broad compositional overlap with those. Our experiments imply, in concordance with the

  10. Influence of crustal dust and sea spray supermicron particle concentrations and acidity on inorganic NO3 aerosol during the 2013 Southern Oxidant and Aerosol Study

    SciTech Connect

    Allen, H. M.; Draper, D. C.; Ayres, B. R.; Ault, A.; Bondy, A.; Takahama, S.; Modini, R. L.; Baumann, K.; Edgerton, E.; Knote, C.; Laskin, A.; Wang, B.; Fry, J. L.

    2015-09-25

    Inorganic aerosol composition was measured in the southeastern United States, a region that exhibits high aerosol mass loading during the summer, as part of the 2013 Southern Oxidant and Aerosol Study (SOAS) campaign. Measurements using a Monitor for AeRosols and GAses (MARGA) revealed two periods of high aerosol nitrate (NO3) concentrations during the campaign. These periods of high nitrate were correlated with increased concentrations of supermicron crustal and sea spray aerosol species, particularly Na+ and Ca2+, and with a shift towards aerosol with larger (1 to 2.5 μm) diameters. We suggest this nitrate aerosol forms by multiphase reactions of HNO3 and particles, reactions that are facilitated by transport of crustal dust and sea spray aerosol from a source within the United States. The observed high aerosol acidity prevents the formation of NH4NO3, the inorganic nitrogen species often dominant in fine-mode aerosol at higher pH. In addition, calculation of the rate of the heterogeneous uptake of HNO3 on mineral aerosol supports the conclusion that aerosol NO3 is produced primarily by this process, and is likely limited by the availability of mineral cation-containing aerosol surface area. Modeling of NO3 and HNO3 by thermodynamic equilibrium models (ISORROPIA II and E-AIM) reveals the importance of including mineral cations in the southeastern United States to accurately balance ion species and predict gas–aerosol phase partitioning.

  11. Science Update: Inorganic Chemistry

    ERIC Educational Resources Information Center

    Rawls, Rebecca

    1978-01-01

    This first in a series of articles describing the state of the art of various branches of chemistry reviews inorganic chemistry, including bioinorganic, photochemistry, organometallic, and solid state chemistries. (SL)

  12. Inorganic and organic structures as interleavers among [bis(1-methyl-3-(p-carboxylatephenyl)triazenide 1-oxide)Ni(II)] complexes to form supramolecular arrangements

    NASA Astrophysics Data System (ADS)

    Santos, Aline Joana Rolina Wohlmuth Alves; dos Santos Hackbart, Helen Cristina; Giacomini, Gabriela Xavier; Bersch, Patrícia; Paraginski, Gustavo Luiz; Hörner, Manfredo

    2016-12-01

    Alternative compounds to capture metal ions are triazenes 1-oxide since they are basic compounds O(N) with negative charge in the deprotonated form. The proximity of both coordination sites (O and N) enables these compounds to have good chelating ability and a tendency to stabilize in the formation of rings with soft and hard transition metal ions. The structure analysis by single crystal X-ray diffraction of compounds (1) and (2) demonstrate the formation of 3D supramolecular arrangements through ion-ion, ion-dipolo and dipolo-dipolo interactions. In one of them, there are [(H2O)2(CH3CH3SO)K2]2+ as linkers of polymerization and, in another complex, there are [(H2O)(CH3CH3SO)Ni(H2O)6]2+ as a linker of polymerization. These linkers act in the polymerization of the novel mononuclear complex [bis(1-methyl (p-carboxylatephenyl) triazenide 1-oxide) NiII] (3). The crystallography analysis of (1) and (2) showed distorted quadratic geometry for Ni (II), thus, there are two axial positions available in Ni (II) to be used in catalysis studies and as sensor or biosensor. In addition, this study shows the support of this novel mononuclear complex of Ni (II) (3) on protonated chitosan chains (4). The compounds (3) and (4) were characterized by spectroscopic analysis, infrared (IR) and energy dispersive X-ray detector (EDS), and by differential scanning calorimetry analysis (DSC). The specificity of ligand 1-methyl (p-carboxyphenyl) triazene 1-oxide to capture potassium and nickel ions will be tested at different pH values, as well as the capacity of the triazenide 1-oxide of Ni (II) complex, supported on chitosan polymer, or not, to act as a catalyst for organic reactions and biomimetic organic reactions.

  13. Sensibility of hydrous ethanol adulteration detection using ultrasonic parameters validated in a metrological base

    NASA Astrophysics Data System (ADS)

    K-K Figueiredo, Monique; Costa-Felix, Rodrigo P. B.; Maggi, Luis E.; Alvarenga, André V.; Romeiro, Gilberto A.

    2011-02-01

    The aim of this study is to identify possible changes in fuels, in this case hydrous ethanol, through ultrasonic parameters such as attenuation and propagation speed. The system setup and method were implemented at Inmetro's Laboratory of Ultrasound. Experiments and method uncertainties were assessed accordingly to ISO/IEC Guide 98 1:2009 (Uncertainty of measurement - Part 1: Introduction to the expression of uncertainty in measurement). Mixtures of ethanol and water varying from 90% to 94% of alcohol in mass were used as testing samples. Attenuation and propagation speed were accurately measured and uncertainties evaluated. The accordingly to Brazilian biofuel regulations, the concentration of water in hydrous ethanol can be accepted at a maximum concentration of 93.8 and minimum of 92.6 of alcohol in mass. To achieve that figure, a functional combination of tested parameters should be implemented. Those results could be used as a tool to identify adulteration of biofuel, even in analysis performed on site.

  14. Evidence for the late formation of hydrous asteroids from young meteoritic carbonates.

    PubMed

    Fujiya, Wataru; Sugiura, Naoji; Hotta, Hideyuki; Ichimura, Koji; Sano, Yuji

    2012-01-17

    The accretion of small bodies in the Solar System is a fundamental process that was followed by planet formation. Chronological information of meteorites can constrain when asteroids formed. Secondary carbonates show extremely old (53)Mn-(53)Cr radiometric ages, indicating that some hydrous asteroids accreted rapidly. However, previous studies have failed to define accurate Mn/Cr ratios; hence, these old ages could be artefacts. Here we develop a new method for accurate Mn/Cr determination, and report a reliable age of 4,563.4+0.4/-0.5 million years ago for carbonates in carbonaceous chondrites. We find that these carbonates have identical ages, which are younger than those previously estimated. This result suggests the late onset of aqueous activities in the Solar System. The young carbonate age cannot be explained if the parent asteroid accreted within 3 million years after the birth of the Solar System. Thus, we conclude that hydrous asteroids accreted later than differentiated and metamorphosed asteroids.

  15. Water Speciation and properties of hydrous model basalt melt at high pressure

    NASA Astrophysics Data System (ADS)

    Bajgain, S. K.; Karki, B. B.

    2013-12-01

    Silicate melts in the Earth's interior are known/expected to be hydrous. Water can make major impact on physical properties including the structure, density, and mobility of melts. The behavior of relevant hydrous melts over most of the mantle pressure regime is poorly constrained. Water solubility increases rapidly with increasing pressure at low pressure [1] and a complete miscibility of liquid MgSiO3 and H2O has been suggested based on high-pressure simulations [2]. We have recently performed first principle molecular dynamics simulations of hydrous model basalt melt at high pressure. Our results show that with increasing pressure, the partial molar volume of water in the melt asymptotically approaches to that of pure water, and both the volumes become identical after certain point. Water is predicted to dissolve in the form of hydroxyls and water molecules at low pressure and as more extended structures at high pressure. The simulated basalt-H2O system commences to behave ideally at pressures above 10 GPa. In contrast, the simulated SiO2-H2O and MgSiO3-H2O systems approach to an ideal limit at much higher pressures of 50 GPa or above. These results imply an unlimited solubility of water in in silicate melts and the water solubility rather appears to be insensitive of composition at high pressure. Existence of water-rich silicate melts over most of the mantle in early history could have made substantial contribution to the origin of hydrosphere [3]. [1] Shen, A. H., and H. Keppler (1997), Direct observation of complete miscibility in the Albite-H2O system, Nature, 385, 710-712. [2] Mookherjee, M., L. Stixrude, and B. Karki (2008), Hydrous silicate melt at high pressure, Nature, 452, 983-986. [3] Matsui, T., and Y. Abe (1986), Evolution of an impact-induced atmosphere and magma ocean on the accreting Earth, Nature, 319, 303-305.

  16. Inorganic Nanoparticles for Multimodal Molecular Imaging

    PubMed Central

    Swierczewska, Magdalena; Lee, Seulki; Chen, Xiaoyuan

    2013-01-01

    Multimodal molecular imaging can offer a synergistic improvement of diagnostic ability over a single imaging modality. Recent development of hybrid imaging systems has profoundly impacted the pool of available multimodal imaging probes. In particular, much interest has been focused on biocompatible, inorganic nanoparticle–based multimodal probes. Inorganic nanoparticles offer exceptional advantages to the field of multimodal imaging owing to their unique characteristics, such as nanometer dimensions, tunable imaging properties, and multifunctionality. Nanoparticles mainly based on iron oxide, quantum dots, gold, and silica have been applied to various imaging modalities to characterize and image specific biologic processes on a molecular level. A combination of nanoparticles and other materials such as biomolecules, polymers, and radiometals continue to increase functionality for in vivo multimodal imaging and therapeutic agents. In this review, we discuss the unique concepts, characteristics, and applications of the various multimodal imaging probes based on inorganic nanoparticles. PMID:21303611

  17. Detectability of hydrous minerals using ONC-T camera onboard the Hayabusa2 spacecraft

    NASA Astrophysics Data System (ADS)

    Kameda, S.; Suzuki, H.; Cho, Y.; Koga, S.; Yamada, M.; Nakamura, T.; Hiroi, T.; Sawada, H.; Honda, R.; Morota, T.; Honda, C.; Takei, A.; Takamatsu, T.; Okumura, Y.; Sato, M.; Yasuda, T.; Shibasaki, K.; Ikezawa, S.; Sugita, S.

    2015-10-01

    The Hayabusa2 spacecraft has three framing cameras (ONC-T, ONC-W1, and ONC-W2) for optical navigation to asteroid 1999 JU3. The ONC-T is a telescopic camera with seven band-pass filters in the visible and near-infrared range. These filters are placed on a wheel, which rotates to put a selected filter for different observations, enabling multiband imaging. Previous ground-based observations suggesting that hydrous materials may be present on the surface of 1999 JU3 and distributed in relatively limited areas. The presence of hydrous minerals indicates that this asteroid experienced only low to moderate temperatures during its formation, suggesting that primordial materials are preserved. In order to find the best sampling sites, we will perform reflectance spectroscopic observations using the ONC-T near the asteroid after arrival. Finding regions rich in hydrous minerals is the key for this remote sensing observation. In preparation for this, we conducted ground-based experiments for the actual ONC-T flight model to confirm the detectability of the absorption band of Fe-rich serpentine. As a result, we detected the absorption band near 0.7 μm by reflectance spectroscopy of CM2 chondrites, such as Murchison and Nogoya, which are known to contain the Fe-rich serpentine, and did not detect any 0.7 μm absorption in Jbilet Winselwan CM2 chondrite with decomposed Fe-rich serpentine.

  18. Hydrous RuO2 nanoparticles as an efficient NIR-light induced photothermal agent for ablation of cancer cells in vitro and in vivo.

    PubMed

    Xiao, Zhiyin; Jiang, Xiaohong; Li, Bo; Liu, Xijian; Huang, Xiaojuan; Zhang, Yuxin; Ren, Qilong; Luo, Jie; Qin, Zongyi; Hu, Junqing

    2015-07-28

    Metal oxides are receiving an incremental attention in recent years for their potential applications in ablation of cancer cells due to their efficient photothermal conversion and good biocompatibility, but the large sizes and poor photo-stability will seriously limit their practical application. Herein, hydrous RuO2 nanoparticles were synthesized by a facile hydrothermal treatment and surface-modified with polyvinylpyrrolidone (PVP) coating. PVP-coated RuO2 nanoparticles exhibit a well dispertion in saline solution, strong characteristic plasmonic absorption in NIR region, enhanced photothermal conversion efficiency of 54.8% and remarkable photo-stability under the irridation of an 808 nm laser. The nanoparticles were further employed as a new photothermal ablation agent for cancer cells which led rapidly to cellular deaths both in vitro and in vivo. PMID:26055486

  19. Theoretical and experimental studies of the spin trapping of inorganic radicals by 5,5-dimethyl-1-pyrroline N-oxide (DMPO). 1. Carbon dioxide radical anion.

    PubMed

    Villamena, Frederick A; Locigno, Edward J; Rockenbauer, Antal; Hadad, Christopher M; Zweier, Jay L

    2006-12-14

    The carbon dioxide radical anion (CO2*-) is known to be generated in vivo through various chemical and biochemical pathways. Electron paramagnetic resonance (EPR) spin trapping with the commonly used spin trap, 5,5-dimethyl-1-pyrroline N-oxide (DMPO), has been employed in the detection of CO2*-. The thermodynamics of CO2*- addition to DMPO was predicted using density functional theory (DFT) at the B3LYP/6-31++G**//B3LYP/6-31G* and B3LYP/6-311+G* levels with the polarizable continuum model (PCM) to simulate the effect of the bulk dielectric effect of water on the calculated energetics. Three possible products of CO2*- addition to DMPO were predicted: (1) a carboxylate adduct, (2) pyrroline-alcohol and (3) DMPO-OH. Experimentally, UV photolysis of H2O2 in the presence of sodium formate (NaHCO2) and DMPO gave an EPR spectrum characteristic of a C-centered carboxylate adduct and is consistent with the theoretically derived hyperfine coupling constants (hfcc). The pKa of the carboxylate adduct was estimated computationally to be 6.4. The mode of CO2*- addition to DMPO is predicted to be governed predominantly by the spin (density) population on the radical, whereas electrostatic effects are not the dominant factor for the formation of the persistent adduct. The thermodynamic behavior of CO2*- in the aqueous phase is predicted to be similar to that of mercapto radical (*SH), indicating that formation of CO2*- in biological systems may have an important role in the initiation of oxidative damage in cells.

  20. Inorganic Phosphor Materials for Lighting.

    PubMed

    Lin, Yuan-Chih; Karlsson, Maths; Bettinelli, Marco

    2016-04-01

    This chapter addresses the development of inorganic phosphor materials capable of converting the near UV or blue radiation emitted by a light emitting diode to visible radiation that can be suitably combined to yield white light. These materials are at the core of the new generation of solid-state lighting devices that are emerging as a crucial clean and energy saving technology. The chapter introduces the problem of white light generation using inorganic phosphors and the structure-property relationships in the broad class of phosphor materials, normally containing lanthanide or transition metal ions as dopants. Radiative and non-radiative relaxation mechanisms are briefly described. Phosphors emitting light of different colors (yellow, blue, green, and red) are described and reviewed, classifying them in different chemical families of the host (silicates, phosphates, aluminates, borates, and non-oxide hosts). This research field has grown rapidly and is still growing, but the discovery of new phosphor materials with optimized properties (in terms of emission efficiency, chemical and thermal stability, color, purity, and cost of fabrication) would still be of the utmost importance. PMID:27573146

  1. Hydrous RuO2 nanoparticles as an efficient NIR-light induced photothermal agent for ablation of cancer cells in vitro and in vivo

    NASA Astrophysics Data System (ADS)

    Xiao, Zhiyin; Jiang, Xiaohong; Li, Bo; Liu, Xijian; Huang, Xiaojuan; Zhang, Yuxin; Ren, Qilong; Luo, Jie; Qin, Zongyi; Hu, Junqing

    2015-07-01

    Metal oxides are receiving an incremental attention in recent years for their potential applications in ablation of cancer cells due to their efficient photothermal conversion and good biocompatibility, but the large sizes and poor photo-stability will seriously limit their practical application. Herein, hydrous RuO2 nanoparticles were synthesized by a facile hydrothermal treatment and surface-modified with polyvinylpyrrolidone (PVP) coating. PVP-coated RuO2 nanoparticles exhibit a well dispertion in saline solution, strong characteristic plasmonic absorption in NIR region, enhanced photothermal conversion efficiency of 54.8% and remarkable photo-stability under the irridation of an 808 nm laser. The nanoparticles were further employed as a new photothermal ablation agent for cancer cells which led rapidly to cellular deaths both in vitro and in vivo.Metal oxides are receiving an incremental attention in recent years for their potential applications in ablation of cancer cells due to their efficient photothermal conversion and good biocompatibility, but the large sizes and poor photo-stability will seriously limit their practical application. Herein, hydrous RuO2 nanoparticles were synthesized by a facile hydrothermal treatment and surface-modified with polyvinylpyrrolidone (PVP) coating. PVP-coated RuO2 nanoparticles exhibit a well dispertion in saline solution, strong characteristic plasmonic absorption in NIR region, enhanced photothermal conversion efficiency of 54.8% and remarkable photo-stability under the irridation of an 808 nm laser. The nanoparticles were further employed as a new photothermal ablation agent for cancer cells which led rapidly to cellular deaths both in vitro and in vivo. Electronic supplementary information (ESI) available: Characterizations including TEM, TG, EDS, etc. See DOI: 10.1039/c5nr00965k

  2. Inorganic separator technology program

    NASA Technical Reports Server (NTRS)

    Smatko, J. S.; Weaver, R. D.; Kalhammer, F. R.

    1973-01-01

    Testing and failure analyses of silver zinc cells with largely inorganic separators were performed. The results showed that the wet stand and cycle life objective of the silver-zinc cell development program were essentially accomplished and led to recommendations for cell composition, design, and operation that should yield further improvement in wet and cycle life. A series of advanced inorganic materials was successfully developed and formulated into rigid and semiflexible separator samples. Suitable screening tests for evaluation of largely inorganic separators were selected and modified for application to the separator materials. The results showed that many of these formulations are potentially superior to previously used materials and permitted selection of three promising materials for further evaluation in silver-zinc cells.

  3. Intermediate-depth earthquake generation: what hydrous minerals can tell us

    NASA Astrophysics Data System (ADS)

    Deseta, N.; Ashwal, L.; Andersen, T. B.

    2012-04-01

    Subduction zone seismicity has commonly been causally related to the dehydration of minerals within the subducting slab(Hacker et al. 2004, Jung et al. (2004), Dobson et al. 2002, Rondenay et al. 2008). Other models for release of intermediate- and deep earthquakes include spontaneous reaction(s) affecting large rock-bodies along overstepped phase boundaries ( e.g. Green and Houston, 1995) and various shear heating-localization models (e.g. Kelemen and Hirth 2007, John et al. 2009). These concepts are principally reliant on seismic and thermo-petrological modeling; both of which are indirect methods of analysis. Recent discoveries of pseudotachylytes (PST) formed under high pressure conditions (Ivrea-Verbano Zone, Italy, Western Gneiss Region, Norway and Corsica) provide the first tangible opportunity to evaluate these models (Austrheim and Andersen, 2004, Lund and Austrheim, 2003, Obata and Karato, 1995, Jin et al., 1998). This case study focuses on observations based on ultramafic and mafic PST within the Ligurian Ophiolite of the high pressure-low temperature metamorphic (HP-LT) 'Shistes Lustres' complex in Cima di Gratera, Corsica (Andersen et al. 2008). These PST have been preserved in pristine lenses of peridotite and gabbro surrounded by schistose serpentinites. The PST range in thickness from 1mm to 25 cm (Andersen and Austrheim, 2006). Petrography and geochemistry on PST from the peridotite and gabbro samples indicates that total/near-total fusion of the local host rock mineral assemblage occurred; bringing up the temperature of shear zone from 350° C to 1400 - 1700° C; depending on the host rock (Andersen and Austrheim, 2006). The composition of the PST is highly variable, even at the thin section scale and this has been attributed to the coarse-grained nature of the host rock, its small scale inhomogeneity and poor mixing of the fusion melt. Almost all the bulk analyses of the PST are hydrous; the peridotitic PST is always hydrous (H2O content from 3

  4. Theoretical and experimental studies of the spin trapping of inorganic radicals by 5,5-dimethyl-1-pyrroline N-oxide (DMPO). 2. Carbonate radical anion.

    PubMed

    Villamena, Frederick A; Locigno, Edward J; Rockenbauer, Antal; Hadad, Christopher M; Zweier, Jay L

    2007-01-18

    Previous studies have shown that the enzyme-mediated generation of carbonate radical anion (CO(3)(.-)) may play an important role in the initiation of oxidative damage in cells. This study explored the thermodynamics of CO(3)(.-) addition to 5,5-dimethyl-1-pyrroline N-oxide (DMPO) using density functional theory at the B3LYP/6-31+G(**)//B3LYP/6-31G* and B3LYP/6-311+G* levels with the polarizable continuum model to simulate the effect of the bulk dielectric effect of water on the calculated energetics. Theoretical data reveal that the addition of CO(3)(.-) to DMPO yields an O-centered radical adduct (DMPO-OCO2) as governed by the spin (density) population on the CO(3)(.-). Electron paramagnetic resonance spin trapping with the commonly used spin trap, DMPO, has been employed in the detection of CO(3)(.-). UV photolysis of H(2)O(2) and DMPO in the presence of sodium carbonate (Na(2)CO(3)) or sodium bicarbonate (NaHCO(3)) gave two species (i.e., DMPO-OCO(2) and DMPO-OH) in which the former has hyperfine splitting constant values of a(N) = 14.32 G, a(beta)-Eta = 10.68 G, and a(gamma-H) = 1.37 G and with a shorter half-life compared to DMPO-OH. The origin of the DMPO-OH formed was experimentally confirmed using isotopically enriched H(2)(17)O(2) that indicates direct addition of HO(.) to DMPO. Theoretical studies on other possible pathways for the formation of DMPO-OH from DMPO-OCO(2) in aqueous solution and in the absence of free HO(.) such as in the case of enzymatically generated CO(3)(.-), show that the preferred pathway is via nucleophilc substitution of the carbonate moiety by H(2)O or HO(-). Nitrite formation has been observed as the end product of CO(3)(.-) trapping by DMPO and is partly dependent on the basicity of solution. The thermodynamic behavior of CO(3)(.-) in the aqueous phase is predicted to be similar to that of the hydroperoxyl (HO(2)(.)) radical. PMID:17214476

  5. Cationic polyelectrolyte induced separation of some inorganic contaminants and their mixture (zirconium silicate, kaolin, K-feldspar, zinc oxide) as well as of the paraffin oil from water.

    PubMed

    Ghimici, Luminita

    2016-03-15

    The flocculation efficiency of a cationic polyelectrolyte with quaternary ammonium salt groups in the backbone, namely PCA5 was evaluated on zirconium silicate (kreutzonit), kaolin, K- feldspar and zinc oxide (ZnO) suspensions prepared either with each pollutant or with their mixture. The effect of several parameters such as settling time, polymer dose and the pollutant type on the separation efficacy was evaluated and followed by optical density and zeta potential measurements. Except for ZnO, the interactions between PCA5 and suspended particles led to low residual turbidity values (around 4% for kreutzonit, 5% for kaolin and 8% for K-feldspar) as well as to the reduction of flocs settling time (from 1200 min to 30 min and 120 min in case of kaolinit and K-feldspar, respectively), that meant a high efficiency in their separation. The negative value of the zeta potential and flocs size measurements, at the optimum polymer dose, point to contribution from charge patch mechanism for the particles flocculation. A good efficiency of PCA5 in separation of paraffin oil (a minimum residual turbidity of 9.8%) has been also found. PMID:26716571

  6. Visible-near infrared spectra of hydrous carbonates, with implications for the detection of carbonates in hyperspectral data of Mars

    NASA Astrophysics Data System (ADS)

    Harner, Patrick L.; Gilmore, Martha S.

    2015-04-01

    We present visible-near infrared (VNIR, 0.35-5 μm) spectra for a suite of hydrous carbonates that may be relevant to the surface of Mars. This includes VNIR spectra for ikaite, nesquehonite, synthetic monohydrocalcite and lansfordite over the 0.35-2.5 μm range that are new to the literature. The spectral features of the hydrous carbonates are dominated by absorptions at ∼1.0, 1.2, 1.4-1.5, 1.9 and 2.8 μm that are due to overtones and combinations of fundamental water and hydroxyl vibrations. Absorptions due to (CO3)2-, Mg-OH, Fe-OH, and/or water are seen at ∼2.3-2.5, 3.4, and 3.9 μm in hydrous Mg and Mg-Fe3+ carbonates containing hydroxyl groups, but are weaker than in the common anhydrous carbonates. When present in the hydrous carbonates, the positions of the centers of the 2.3 μm and/or 2.5 μm absorptions are often shifted relative to the anhydrous carbonates, which may be diagnostic. Some or all of the (CO3)2- absorptions typical of anhydrous carbonates are weak to absent in the hydrous carbonates, and thus this group may be difficult to distinguish from other hydrous minerals like sulfates, phyllosilicates or chlorides in Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) data using standard spectral search parameters for anhydrous carbonates. We present strategies for recognizing hydrous carbonates in CRISM data using combinations of spectral parameters that measure the intensity and shape of the water-related absorptions in these minerals.

  7. Neutron and X-ray diffraction study on the hydrous SiO2 glass under pressure

    NASA Astrophysics Data System (ADS)

    Urakawa, S.; Inoue, T.; Hattori, T.; Sano, A.; Kikegawa, T.; Funakoshi, K. I.; Mibe, K.; Kohara, S.

    2015-12-01

    Water has significant effects on the physical properties and the structure of silicate melts. Studies on hydrous silicate melts are, therefore, important to understand the magma-related phenomena of the planetary interior. Neutron has an advantage over X-ray to study the structure of hydrous melts. We have developed the high-pressure neutron diffraction method on the amorphous silicates with water at the PLANTE beamline of MLF, J-PARC. Here we report the results of in-situ neutron diffraction experiments on the hydrous silica glass at room temperature up to 10 GPa as well as X-ray diffraction study. Hydrous silica glass was synthesized by quenching from liquid at 3 GPa, in which D2O content is 13 wt.%. Neutron diffraction experiments were carried out at BL11 of MLF, J-PARC and X-ray studies were done at BL04B2 of SPring-8 and AR-NE5 of Photon Factory. On the neutron and X-ray spectra, the FSDP of hydrous glass locates at the higher Q-side than dry one, indicating the breakdown of network structure of silica glass by an addition of water. The FSDP shifts toward higher-Q side with increasing pressure parallel to that of dry silica glass. The radial distribution functions shows that the SiO4 unit does not change up to 10 GPa but the Si-Si-distance decreases with pressure. These show that the intermediate range order, which consists of the network of SiO4 tetrahedra, shrinks with increasing pressure. The changes of silica framework with pressure in hydrous silica glass are similar to those in dry silica glass. On the other hand, neutron diffraction shows the D-O distance in hydrous silica glass is nearly constant up to 10 GPa.

  8. Hybrid inorganic-organic materials: Novel poly(propylene oxide)-based ceramers, abrasion-resistant sol-gel coatings for metals, and epoxy-clay nanocomposites, with an additional chapter on: Metallocene-catalyzed linear polyethylene

    NASA Astrophysics Data System (ADS)

    Jordens, Kurt

    1999-12-01

    The sol-gel process has been employed to generate hybrid inorganic-organic network materials. Unique ceramers were prepared based on an alkoxysilane functionalized soft organic oligomer, poly(propylene oxide (PPO), and tetramethoxysilane (TMOS). Despite the formation of covalent bonds between the inorganic and organic constituents, the resulting network materials were phase separated, composed of a silicate rich phase embedded in a matrix of the organic oligomer chains. The behavior of such materials was similar to elastomers containing a reinforcing filler. The study focused on the influence of initial oligomer molecular weight, functionality, and tetramethoxysilane, water, and acid catalyst content on the final structure, mechanical and thermal properties. The sol-gel approach has also been exploited to generate thin, transparent, abrasion resistant coatings for metal substrates. These systems were based on alkoxysilane functionalized diethylenetriamine (DETA) with TMOS, which generated hybrid networks with very high crosslink densities. These materials were applied with great success as abrasion resistant coatings to aluminum, copper, brass, and stainless steel. In another study, intercalated polymer-clay nanocomposites were prepared based on various epoxy networks montmorillonite clay. This work explored the influence of incorporated clay on the adhesive properties of the epoxies. The lap shear strength decreased with increasing day content This was due to a reduction in the toughness of the epoxy. Also, the delaminated (or exfoliated) nanocomposite structure could not be generated. Instead, all nanocomposite systems possessed an intercalated structure. The final project involved the characterization of a series of metallocene catalyzed linear polyethylenes, produced at Phillips Petroleum. Polyolefins synthesized with such new catalyst systems are becoming widely available. The influence of molecular weight and thermal treatment on the mechanical, rheological

  9. Lead and compounds (inorganic)

    Integrated Risk Information System (IRIS)

    Lead and compounds ( inorganic ) ; CASRN 7439 - 92 - 1 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for

  10. Geological and Inorganic Materials.

    ERIC Educational Resources Information Center

    Jackson, L. L.; And Others

    1989-01-01

    Presents a review focusing on techniques and their application to the analysis of geological and inorganic materials that offer significant changes to research and routine work. Covers geostandards, spectroscopy, plasmas, microbeam techniques, synchrotron X-ray methods, nuclear activation methods, chromatography, and electroanalytical methods.…

  11. ADSORPTION OF THE ISOXAFLUTOLE DEGRADATES TO ALUMINUM AND IRON HYDROUS OXIDES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Isoxaflutole is relatively new herbicide which rapidly hydrolyzes to a diketonitrile (DKN) degradate after field application. Subsequently, DKN is degraded to form a benzoic acid (BA) derivative and other inactive degradates. However, our understanding of soil solid phases influencing or governing t...

  12. Partitioning of protactinium, uranium, thorium and other trace elements between columbite and hydrous silicate melt

    NASA Astrophysics Data System (ADS)

    Huang, F.; Schmidt, M. W.; Günther, D.; Eikenberg, J.

    2009-12-01

    U-series disequilibria are a unique powerful tool to constrain the time-scales and processes of magmatism in mid-ocean ridge, intra-plate, and convergent margin settings. 235U-231Pa is one of the important parent-daughter pairs (231Pa half life = 33 kyr) because protactinium is normally much more incompatible than U during magmatism and thus the ubiquitously observed 231Pa excess in young igneous rocks most likely reflects melting processes. However, because of the extreme incompatibility of protactinium in most silicate minerals (mineral/meltDPa < 10-5), it is quite challenging to experimentally investigate partition coefficient of Pa. Furthermore, it is unclear whether Pa is always +5 or possibly more reduced at natural magmatic conditions, in particular in a reduced mantle. This significantly limits our understanding of the chemical behavior of Pa and applications of U-series disequilibrium data to the study of magmatism. Columbite (Mn(Nb,Ta)2O6) is a mineral with Nb5+ and Ta5+ as major elements, and occurs in per-aluminous granites and pegmatites. Because protactinium is expected to be +5 charged at crustal oxygen fugacities, and Pa5+ has an ionic radius close to Nb5+ and Ta5+, Nb and Ta have been used as proxy elements to constrain partitioning of Pa between minerals and melt using lattice strain modeling. Nb and Ta are strongly compatible in columbite (columbite/meltDNb-Ta ~ 10), and lattice strain modeling based on physical characteristics of the Nb-Ta site where Pa should be incorporated predicts that columbite/meltDPa5+ should be around 0.2, high enough to be experimentally determined at the permissible Pa doping level of 10 ppm (bulk). Experiments were run in a piston cylinder apparatus at 0.5 GPa and 1115 oC using Pt double capsules with NNO or FMQ as external fO2 buffers. The starting material is a hydrous per-aluminous granitic composition, doped with Pa solution in the Paul Scherrer Institute and also contains other trace elements including U, Th, REE

  13. Electrical conductivity of dense hydrous magnesium silicates with implication for conductivity in the stagnant slab

    NASA Astrophysics Data System (ADS)

    Guo, Xinzhuan; Yoshino, Takashi

    2013-05-01

    Electrical conductivities of dense hydrous magnesium silicates (DHMS), phase A, super-hydrous phase B (SuB) and phase D, were measured by means of impedance spectroscopy in the frequency range of 10-1-106 Hz at temperatures up to 775, 700 and 700 K and pressures of 10, 18 and 22 GPa, respectively. For all phases, the increase in electrical conductivity (σ) with temperature follows the Arrhenian formula: σ=σ0exp(-(ΔH/kT)). The pre-exponential factors (σ0) and activation enthalpies (ΔH) of phase A, SuB and phase D yield values of 7.28±0.82 S/m and 0.77±0.01 eV, 292±48 S/m and 0.83±0.01 eV and 1342±154 and 0.75±0.01 eV, respectively. Higher pressure DHMS phases show higher conductivity values. The electrical conductivities of phase D and super hydrous phase B are about two and one orders of magnitude higher than that of phase A in the same temperature range, respectively. Although the proton conduction is considered to be a dominant mechanism, there is no clear relationship between water content and conductivity. Rather the conductivity of DHMS phase is closely related to the O⋯O distance. The conductivity-depth profiles for a cold subduction zone were constructed based on the phase proportion predicted in the descending slab. The results show distinctly lower conductivity values than those geophysically observed beneath the northeastern China and the Philippine Sea, where the cold slab stagnates in the mantle transition zone. Consequently, the DHMS phases themselves cannot be a main contributor to enhance the conductivity in the stagnant slab. Dehydration of the stagnant slab would strongly enhance the conductivities in the transition zone beneath northeastern China and Philippine Sea.

  14. Dehydration of hydrous minerals and formation of nanocrystals by frictional heating in experimental seismic fault zones

    NASA Astrophysics Data System (ADS)

    Jung, S.; Chae, S.; Ree, J.; Hirose, T.; Kim, J.

    2013-12-01

    Recent studies on experimental and natural carbonate faults have shown that the formation of nanocrystals produced by thermal decomposition or deformation during seismic slip can lead to significant slip weakening and large earthquakes. Natural fault rocks contain various hydrous minerals that can be easily decomposed by frictional heating and possibly form nanocrystals. However, thermal decomposition of hydrous minerals during seismic slip has not been studied much. We performed rotary-shear experiments on amphibolites and metapelites at seismic slip rates (up to 1.3 m/s) and at normal stress of 2-16 MPa to investigate thermal decomposition of hydrous minerals. The frictional property of the metapelites is characterized by two transient peak frictions followed by a final slip weakening leading to a steady-state friction, while the amphibolites exhibit three peak frictions and subsequent steady-state friction. The simulated fault zones consist of a principal slip zone (PSZ) mantled by damage zone (DZ). The PSZ is a molten layer laden with clasts of quartz (metapelites) and plagioclase (amphibolites). Hornblendes of the amphibolites and biotites of the metapelites in DZ show dark stripes along cleavage planes in plane-polarized light (PPL). These hornblende and biotite grains become totally dark in PPL immediately adjacent to PSZ. Scanning electron microscopy (SEM) shows that tiny holes (1 to 10 μm) occur in dark colored biotites of DZ. The darker stripes of hornblende appear rugged in SEM images. Selected area electron diffraction (SAED) and high-resolution transmission electron microscope (HRTEM) analyses reveal that the dark cleavage stripes of biotite and hornblende consist of cavity- and nanocrystal-bands. We interpret these cavity- and nanocrystal-bands of the dark cleavage stripes are products of biotite- and hornblende-dehydration preferably occurring along cleavage planes. We believe nanocrystals not only lower friction but also facilitate reaction and

  15. Methane production by treating vinasses from hydrous ethanol using a modified UASB reactor

    PubMed Central

    2012-01-01

    Background A modified laboratory-scale upflow anaerobic sludge blanket (UASB) reactor was used to obtain methane by treating hydrous ethanol vinasse. Vinasses or stillage are waste materials with high organic loads, and a complex composition resulting from the process of alcohol distillation. They must initially be treated with anaerobic processes due to their high organic loads. Vinasses can be considered multipurpose waste for energy recovery and once treated they can be used in agriculture without the risk of polluting soil, underground water or crops. In this sense, treatment of vinasse combines the elimination of organic waste with the formation of methane. Biogas is considered as a promising renewable energy source. The aim of this study was to determine the optimum organic loading rate for operating a modified UASB reactor to treat vinasse generated in the production of hydrous ethanol from sugar cane molasses. Results The study showed that chemical oxygen demand (COD) removal efficiency was 69% at an optimum organic loading rate (OLR) of 17.05 kg COD/m3-day, achieving a methane yield of 0.263 m3/kg CODadded and a biogas methane content of 84%. During this stage, effluent characterization presented lower values than the vinasse, except for potassium, sulfide and ammonia nitrogen. On the other hand, primers used to amplify the 16S-rDNA genes for the domains Archaea and Bacteria showed the presence of microorganisms which favor methane production at the optimum organic loading rate. Conclusions The modified UASB reactor proposed in this study provided a successful treatment of the vinasse obtained from hydrous ethanol production. Methanogen groups (Methanobacteriales and Methanosarcinales) detected by PCR during operational optimum OLR of the modified UASB reactor, favored methane production. PMID:23167984

  16. Water and Slabs in the Transition Zone - Hydrous Ringwoodite in Diamond

    NASA Astrophysics Data System (ADS)

    Pearson, D. G.; Brenker, F. E.; Nestola, F.; McNeill, J.; Nasdala, L.; Hutchison, M.; Matveev, S.; Mather, K.; Vincze, L.; Schmitz, S.; Vekemens, B.

    2014-12-01

    Theory and experiments have shown that the Earth's Transition Zone (TZ) could be a major repository for water, due to the ability of the higher-pressure polymorphs of olivine - wadsleyite and ringwoodite - to host up to ~2.5wt. % H2O. Despite experimental demonstration of the water-bearing capacity of these phases, geophysical probes such as electrical conductivity have provided conflicting results, and the issue of whether the TZ contains abundant water remains highly controversial. We report X-ray diffraction, Raman and infra-red spectroscopic evidence for the first terrestrial occurrence of any higher pressure polymorph of olivine: ringwoodite, included in a diamond from Juína, Brazil. The ringwoodite occurs with a Ca-walstromite phase that we interpret to be retrogressed Ca-silicate perovskite. The most likely interpretation of this two-phase assemblage is that it represents a partially retrogressed portion of a somewhat Fe-rich peridotitic mantle, in which hydrous ringwoodite, and former CaSiO3- perovskite co-existed above 15GPa. The ringwoodite has a Mg# of ~ 75, suggesting that it may be mantle hybrised with a more fertile component such as subducted oceanic crust. The water-rich nature of this inclusion (~1.5 wt%), along with the preservation of ringwoodite, is the first direct evidence that, at least locally, the TZ is hydrous, to about 1 wt%. As well as being in agreement with recent magnetotelluric estimates of the TZ water content, this amount of water helps to reconcile measured TZ seismic velocities with those predicted from lab experiments. The finding also indicates that some kimberlites must have their primary sources in this deep mantle region. The high water content of the ringwoodite suggests that it was not close to the mantle geotherm when trapped in the diamond. This may be an indication that the the assemblage was part of a water-rich subducted slab out of thermal equilibrium, within the transition zone. The water-rich nature of the

  17. Infrared spectroscopy and hydrogen isotope geochemistry of hydrous silicate glasses. Progress report

    SciTech Connect

    Epstein, S.; Stolper, E.

    1992-03-01

    The focus of this project is the combined appication of infrared spectroscopy and stable isotope geochemistry to the study of hydrogen-bearing species dissolved in silicate melts and glasses. We are conducting laboratory experiments aimed at determining the fractionation of D and H between melt species (OH and H{sub 2}O) and hydrous vapor and the diffusivities of these species in glasses and melts. Knowledge of these parameters is critical to understanding the behavior of hydrogen isotopes during igneous processes and hydrothermal processes. These results also could be valuable in application of glass technology to development of nuclear waste disposal strategies.

  18. Stability of Pure Hydrous Silica at Geotherm Temperatures up to 70 GPa

    NASA Astrophysics Data System (ADS)

    Nisr, C.; Shim, S. H.; Leinenweber, K. D.; Hervig, R. L.; Prakapenka, V.; Meng, Y.; Liu, Z.

    2015-12-01

    Stishovite, in the rutile structure with octahedrally coordinated silicon, is expected to exist in silica rich parts of subducted oceanic slabs and crustal fragments in the Earth's mantle, and has been considered for a long time to be essentially anhydrous. However, Spektor et al., (2011) have shown that ~1.3 wt% can be incorporated into pure Al-free stishovite at 10 GPa and 723 K. Yet, the stability and physical properties of hydrous silica at mantle related pressures and temperatures are unknown. We have synthesized hydrous silica samples in the multi anvil press at 9-20 GPa and 700-900 K, and in the laser-heated diamond anvil cell at 17-70 GPa and 1400-2100 K. Three different sample setups have been used: dry silica gel in an H2O medium, anhydrous stishovite in an H2O medium, and hydrous silica gel in a Ne or Ar medium. The presence of percent level of water was found by Secondary Ion Mass Spectrometry, and Raman and Infrared spectroscopy measurements. X-ray diffraction patterns show that the unit-cell volumes of the recovered stishovite samples are greater by 0.2-3.9 % compared with anhydrous stishovite at 1 bar. The unit-cell volumes show strong linear correlation with their c/a ratio suggesting that the same OH substitution mechanism persists for a wide range of water content. Based on unit-cell volumes vs water content calibration by Spektor et al., (2011), our samples contain 0.3-7.9 wt% H2O. We found that pure silica is capable of containing as much as 4.9 wt% of H2O at temperatures close to those of the mantle geotherm (e.g., sample synthesized at ~1997 K and ~67 GPa). The highest water contents were found at the highest pressures, suggesting that the pressure stabilizes OH in dense silica. X-ray diffraction patterns have also shown several new diffraction lines upon compression and heating which appear from 45 GPa (1500-2100 K) and are observed up to 100 GPa. The peaks appear to belong to a new hydrous silica phase stable at higher pressures and

  19. Geological Sequestration of CO2 by Hydrous Carbonate Formation with Reclaimed Slag

    SciTech Connect

    Von L. Richards; Kent Peaslee; Jeffrey Smith

    2008-02-06

    The concept of this project is to develop a process that improves the kinetics of the hydrous carbonate formation reaction enabling steelmakers to directly remove CO2 from their furnace exhaust gas. It is proposed to bring the furnace exhaust stream containing CO2 in contact with reclaimed steelmaking slag in a reactor that has an environment near the unit activity of water resulting in the production of carbonates. The CO2 emissions from the plant would be reduced by the amount sequestered in the formation of carbonates. The main raw materials for the process are furnace exhaust gases and specially prepared slag.

  20. Setting constraints on the nature and origin of the two major hydrous sulfates on Mars: Monohydrated and polyhydrated sulfates

    NASA Astrophysics Data System (ADS)

    Wang, Alian; Jolliff, Bradley L.; Liu, Yang; Connor, Kathryn

    2016-04-01

    Monohydrated Mg sulfate (MgSO4·H2O) and polyhydrated sulfate are the most common and abundant hydrous sulfates observed thus far on Mars. They are widely distributed and coexist in many locations. On the basis of results from two new sets of experiments, in combination with past experimental studies and the subsurface salt mineralogy observed at a saline playa (Dalangtan, DLT) in a terrestrial analogue hyperarid region on the Tibet Plateau, we can now set new constraints on the nature and origin of these two major Martian sulfates. Starkeyite (MgSO4·4H2O) is the best candidate for polyhydrated sulfate. MgSO4·H2O in the form of "LH-1w," generated from dehydration of Mg sulfates with high degrees of hydration, is the most likely mineral form for the majority of Martian monohydrated Mg sulfate. Two critical properties of Mg sulfates are responsible for the coexistence of these two phases that have very different degrees of hydration: (1) the metastability of a substructural unit in starkeyite at relatively low temperatures, and (2) catalytic effects attributed to coprecipitated species (sulfates, chlorides, oxides, and hydroxides) from chemically complex brines that help overcome the metastability of starkeyite. The combination of these two properties controls the coexistence of the LH-1w layer and starkeyite layers at many locations on Mars, which sometimes occur in an interbedded stratigraphy. The structural H2O held by these two broadly distributed sulfates represents a large H2O reservoir at the surface and in the shallow subsurface on current Mars.

  1. Supported inorganic membranes

    DOEpatents

    Sehgal, Rakesh; Brinker, Charles Jeffrey

    1998-01-01

    Supported inorganic membranes capable of molecular sieving, and methods for their production, are provided. The subject membranes exhibit high flux and high selectivity. The subject membranes are substantially defect free and less than about 100 nm thick. The pores of the subject membranes have an average critical pore radius of less than about 5 .ANG., and have a narrow pore size distribution. The subject membranes are prepared by coating a porous substrate with a polymeric sol, preferably under conditions of low relative pressure of the liquid constituents of the sol. The coated substrate is dried and calcined to produce the subject supported membrane. Also provided are methods of derivatizing the surface of supported inorganic membranes with metal alkoxides. The subject membranes find use in a variety of applications, such as the separation of constituents of gaseous streams, as catalysts and catalyst supports, and the like.

  2. NMR determination of carbon aromatization during hydrous pyrolysis of coals from the Mesaverde group, Greater Green river basin

    SciTech Connect

    Miknis, F.P.; Netzel, D.A.; Surdam, R.C.

    1995-12-01

    Solid-state {sup 13}C NMR measurements have been made on the residues from hydrous pyrolysis experiments conducted on Almond and Lance Formation coals from the Upper Cretaceous Mesaverde Group in the Green River Basin. Only a small percentage of the total carbon (13%) was converted to volatile products for both coals during hydrous pyrolysis. An accounting of the aliphatic carbon was obtained by comparing the aliphatic carbon in the gas, oil and residue products with that of the starting coals. The amount of aliphatic carbon in the volatile products and residue was not sufficient to account for the total amount of aliphatic carbon that disappeared. From this it was inferred that a substantial portion of the aliphatic carbon aromatized during hydrous pyrolysis, (48 and 56% for the Almond and Lance coal, respectively). These and additional results on coal maturation in the natural environment will be discussed.

  3. Material and system for catalytic reduction of nitrogen oxide in an exhaust stream of a combustion process

    DOEpatents

    Gardner, Timothy J.; Lott, Stephen E.; Lockwood, Steven J.; McLaughlin, Linda I.

    1998-01-01

    A catalytic material of activated hydrous metal oxide doped with platinum, palladium, or a combination of these, and optionally containing an alkali or alkaline earth metal, that is effective for NO.sub.X reduction in an oxidizing exhaust stream from a combustion process is disclosed. A device for reduction of nitrogen oxides in an exhaust stream, particularly an automotive exhaust stream, the device having a substrate coated with the activated noble-metal doped hydrous metal oxide of the invention is also provided.

  4. First-principles prediction of a high-pressure hydrous phase of AlOOH

    NASA Astrophysics Data System (ADS)

    Tsuchiya, Jun; Tsuchiya, Taku

    2011-02-01

    We have predicted a high-pressure hydrous phase of AlOOH stabilizing at ˜170 GPa by first-principles density-functional calculations. The structure predicted has a cubic pyrite-type AlO2 framework with interstitial H atoms forming symmetric hydrogen bonds, whose symmetry is assigned to the space group Pa3¯ (No. 205). The predicted δ-AlOOH to the pyrite-type phase sequence is analogous to a recent theoretical and experimental discovery of high-pressure phase evolution in InOOH and invokes the high-pressure phase relationship in SiO2, but the transition pressure is much greater in AlOOH than in InOOH. Relative enthalpies also indicate that the dissociation of this phase into a CaIrO3-type phase of Al2O3 plus ice X finally occurs at a further pressure of 300 GPa. The present results suggest that AlOOH has an unexpectedly wide stability range in pressure compared to common hydrous materials.

  5. Remote Pulsed Laser Raman Spectroscopy System for Detecting Qater, Ice, and Hydrous Minerals

    NASA Technical Reports Server (NTRS)

    Garcia, Christopher S.; Abedin, M. Nuraul; Sharma, Shiv K.; Misra, Anupam K.; Ismail, Syed; Singh, Upendra; Refaat, Tamer F.; Elsayed-Ali, Hani; Sandford, Steve

    2006-01-01

    For exploration of planetary surfaces, detection of water and ice is of great interest in supporting existence of life on other planets. Therefore, a remote Raman spectroscopy system was demonstrated at NASA Langley Research Center in collaboration with University of Hawaii for detecting ice-water and hydrous minerals on planetary surfaces. In this study, a 532 nm pulsed laser is utilized as an excitation source to allow detection in high background radiation conditions. The Raman scattered signal is collected by a 4-inch telescope positioned in front of a spectrograph. The Raman spectrum is analyzed using a spectrograph equipped with a holographic super notch filter to eliminate Rayleigh scattering, and a holographic transmission grating that simultaneously disperses two spectral tracks onto the detector for higher spectral range. To view the spectrum, the spectrograph is coupled to an intensified charge-coupled device (ICCD), which allows detection of very weak Stokes line. The ICCD is operated in gated mode to further suppress effects from background radiation and long-lived fluorescence. The sample is placed at 5.6 m from the telescope, and the laser is mounted on the telescope in a coaxial geometry to achieve maximum performance. The system was calibrated using the spectral lines of a Neon lamp source. To evaluate the system, Raman standard samples such as calcite, naphthalene, acetone, and isopropyl alcohol were analyzed. The Raman evaluation technique was used to analyze water, ice and other hydrous minerals and results from these species are presented.

  6. Can hydrous minerals account for the observed mid-latitude water on Mars?

    SciTech Connect

    Bish, D. L.; Vaniman, D. T.; Fialips, C. I.; Carey, J. W.; Feldman, W. C.

    2003-01-01

    Great interest was generated with the discovery by the Odyssey spacecraft OC heterogeneously distributed hydrogcn at martian mid-latitudes, suggesting that large areas of the near-equatorial highlands contain near-surface deposits of 'chemically and/or physically bound 1120 and/or OH' in amounts up to 3.8% equivalent H20. More recent interpretations of the Odyssey data using new calibrations suggest that some near-equatorial areas, such as Arabia Terra, contain up to 8.5f I .3% water-equivalent hydrogen. Such shallow occurrences (hydrous silicate phases, notably clay minerals and zeolites, have been proposed as possible M20-bearing constituents on Mars, and both groups of minerals are common terrestrial alteration products of hydrovolcanic basaltic ashes and palagonitic material comparable io those that may be widespread on Mars. Smectites within martian meteorites, attributed to hydrous alteration on Mars rather than on Earth, provide direct evidence of clay minerals from Mars. In addition, new thermal emission spectrometer (TES) data provide evidence for unspecified zeolites in martian surface dust, and concluded that spectral deconvolution of MGS TES and Mariner 9 IRIS data is consistent with the presence of zeolite in the martian surface dust.

  7. Enhanced Lithium-ion intercalation properties of coherent hydrous vanadium pentoxide-carbon cryogels nanocomposites

    SciTech Connect

    Pan, Anqiang; Liu, Dawei; Zhou, Xiaoyuan; Garcia, Betzaita Betalla; Liang, Shu-quan; Liu, Jun; Cao, Guozhong

    2010-06-01

    Coherent hydrous vanadium pentoxide (V2O5•nH2O) - carbon cryogels (CCs) nanocomposites were synthesized by electrodeposition of vanadium pentoxide onto the porous carbon scaffold which was derived from resorcinol (R) and formaldehyde (F) organic hydrogels. As-fabricated nanocomposites were characterized by scanning electron microscopy (SEM), along with EDAX and nitrogen sorption isotherms which suggested vanadium pentoxide incorporated in the pores of carbon cryogels. The nanocomposites showed much improved discharge capacity and better cyclic stability as compared to hydrous vanadium pentoxide films deposited on platinum foil. The discharge capacity of the nanocomposites reached 280 mAh/g based on the mass of the vandium pentoxide at a current density of 100mA/g and it possessed good cycle stability at different discharge rate. The results demonstrated that electrochemical performances, such as specific discharge capacitance and reversibility of the composite electrode, could be greatly enhanced by the introduction of carbon cryogels (CCs) scaffold with three-dimensionally interconnected porous structure in which V2O5•nH2O homogeneously dispersed.

  8. Remote pulsed laser Raman spectroscopy system for detecting water, ice, and hydrous minerals

    NASA Astrophysics Data System (ADS)

    Garcia, Christopher S.; Abedin, M. Nurul; Sharma, Shiv K.; Misra, Anupam K.; Ismail, Syed; Singh, Upendra N.; Refaat, Tamer F.; Elsayed-Ali, Hani E.; Sandford, Steve P.

    2006-08-01

    For exploration of planetary surfaces, detection of water and ice is of great interest in supporting existence of life on other planets. Therefore, a remote Raman spectroscopy system was demonstrated at NASA Langley Research Center in collaboration with the University of Hawaii for detecting ice-water and hydrous minerals on planetary surfaces. In this study, a 532 nm pulsed laser is utilized as an excitation source to allow detection in high background radiation conditions. The Raman scattered signal is collected by a 4-inch telescope positioned in front of a spectrograph. The Raman spectrum is analyzed using a spectrograph equipped with a holographic super notch filter to eliminate Rayleigh scattering, and a holographic transmission grating that simultaneously disperses two spectral tracks onto the detector for higher spectral range. To view the spectrum, the spectrograph is coupled to an intensified charge-coupled device (ICCD), which allows detection of very weak Stokes line. The ICCD is operated in gated mode to further suppress effects from background radiation and long-lived fluorescence. The sample is placed at 5.6 m from the telescope, and the laser is mounted on the telescope in a coaxial geometry to achieve maximum performance. The system was calibrated using the spectral lines of a Neon lamp source. To evaluate the system, Raman standard samples such as calcite, naphthalene, acetone, and isopropyl alcohol were analyzed. The Raman evaluation technique was used to analyze water, ice and other hydrous minerals and results from these species are presented.

  9. Generation of aliphatic acid anions and carbon dioxide by hydrous pyrolysis of crude oils

    USGS Publications Warehouse

    Kharaka, Y.K.; Lundegard, P.D.; Ambats, G.; Evans, William C.; Bischoff, J.L.

    1993-01-01

    Two crude oils with relatively high (0.60 wt%) and low (0.18 wt%) oxygen contents were heated in the presence of water in gold-plated reactors at 300??C for 2348 h. The high-oxygen oil was also heated at 200??C for 5711 h. The compositions of aqueous organic acid anions of the oils and of the headspace gases were monitored inn order to investigate the distribution of organic acids that can be generated from liquid petroleum. The oil with higher oxygen content generated about five times as much organic anions as the other oil. The dominant organic anions produced were acetate, propionate and butyrate. Small amounts of formate, succinate, methyl succinate and oxalate were also produced. The dominant oxygen-containing product was CO2, as has been observed in similar studies on the hydrous pyrolysis of kerogen. These results indicate that a significant portion (10-30%) of organic acid anions reported i be generated by thermal alteration of oils in reservoir rocks. The bulk of organic acid anions present in formation waters, however, is most likely generated by thermal alteration of kerogen in source rocks. Kerogen is more abundant than oil in sedimentary basins and the relative yields of organic acid anions reported from the hydrous pyrolysis of kerogen are much higher than the yields obtained for the two oils. ?? 1993.

  10. Inorganic: the other mercury.

    PubMed

    Risher, John F; De Rosa, Christopher T

    2007-11-01

    There is a broad array of mercury species to which humans may be exposed. While exposure to methylmercury through fish consumption is widely recognized, the public is less aware of the sources and potential toxicity of inorganic forms of mercury. Some oral and laboratory thermometers, barometers, small batteries, thermostats, gas pressure regulators, light switches, dental amalgam fillings, cosmetic products, medications, cultural/religious practices, and gold mining all represent potential sources of exposure to inorganic forms of mercury. The route of exposure, the extent of absorption, the pharmacokinetics, and the effects all vary with the specific form of mercury and the magnitude and duration of exposure. If exposure is suspected, a number of tissue analyses can be conducted to confirm exposure or to determine whether an exposure might reasonably be expected to be biologically significant. By contrast with determination of exposure to methylmercury, for which hair and blood are credible indicators, urine is the preferred biological medium for the determination of exposure to inorganic mercury, including elemental mercury, with blood normally being of value only if exposure is ongoing. Although treatments are available to help rid the body of mercury in cases of extreme exposure, prevention of exposure will make such treatments unnecessary. Knowing the sources of mercury and avoiding unnecessary exposure are the prudent ways of preventing mercury intoxication. When exposure occurs, it should be kept in mind that not all unwanted exposures will result in adverse health consequences. In all cases, elimination of the source of exposure should be the first priority of public health officials.

  11. Inorganic: the other mercury.

    PubMed

    Risher, John F; De Rosa, Christopher T

    2007-11-01

    There is a broad array of mercury species to which humans may be exposed. While exposure to methylmercury through fish consumption is widely recognized, the public is less aware of the sources and potential toxicity of inorganic forms of mercury. Some oral and laboratory thermometers, barometers, small batteries, thermostats, gas pressure regulators, light switches, dental amalgam fillings, cosmetic products, medications, cultural/religious practices, and gold mining all represent potential sources of exposure to inorganic forms of mercury. The route of exposure, the extent of absorption, the pharmacokinetics, and the effects all vary with the specific form of mercury and the magnitude and duration of exposure. If exposure is suspected, a number of tissue analyses can be conducted to confirm exposure or to determine whether an exposure might reasonably be expected to be biologically significant. By contrast with determination of exposure to methylmercury, for which hair and blood are credible indicators, urine is the preferred biological medium for the determination of exposure to inorganic mercury, including elemental mercury, with blood normally being of value only if exposure is ongoing. Although treatments are available to help rid the body of mercury in cases of extreme exposure, prevention of exposure will make such treatments unnecessary. Knowing the sources of mercury and avoiding unnecessary exposure are the prudent ways of preventing mercury intoxication. When exposure occurs, it should be kept in mind that not all unwanted exposures will result in adverse health consequences. In all cases, elimination of the source of exposure should be the first priority of public health officials. PMID:18044248

  12. Fabrication of flexible and self-standing inorganic-organic three phase magneto-dielectric PVDF based multiferroic nanocomposite films through a small loading of graphene oxide (GO) and Fe3O4 nanoparticles.

    PubMed

    Jayakumar, O D; Abdelhamid, Ehab H; Kotari, Vasundhara; Mandal, Balaji P; Rao, Rekha; Jagannath; Naik, Vaman M; Naik, Ratna; Tyagi, A K

    2015-09-28

    Flexible inorganic-organic magneto-electric (ME) nanocomposite films (PVDF, PVDF-GO, PVDF-Fe3O4 and PVDF-GO-Fe3O4), composed of well-dispersed graphene oxide (GO 5 wt%) and magnetic Fe3O4 nanoparticles (5 wt%) embedded into a poly(vinylidene-fluoride) (PVDF) matrix, have been prepared by a solvent casting route. The magnetic, ferroelectric, dielectric, magneto-dielectric (MD) coupling and structural properties of these films have been systematically investigated. Magnetic (Ms = 2.21 emu g(-1)) and ferroelectric (P = 0.065 μC cm(-2)) composite films of PVDF-GO-Fe3O4 (PVDF loaded with 5% GO and 5% Fe3O4) with an MD coupling of 0.02% at room temperature (RT) showed a three times higher dielectric constant than that of the pure PVDF film, with a dielectric loss as low as 0.6. However, the PVDF-Fe3O4 film, which exhibited improved magnetic (Ms = 2.5 emu g(-1)) and MD coupling (0.04%) properties at RT with a lower dielectric loss (0.3), exhibited decreased ferroelectric properties (P = 0.06 μC cm(-2)) and dielectric constant compared to the PVDF-GO-Fe3O4 film. MD coupling measurements carried out as a function of temperature on the multi-functional PVDF-GO-Fe3O4 film showed a systematic increase in MD values up to 100 K and a decrease thereafter. The observed magnetic, ferroelectric, dielectric, MD coupling and structural properties of the nanocomposite films are attributed to the homogeneous dispersion and good alignment of Fe3O4 nanoparticles and GO in the PVDF matrix along with a partial conversion of nonpolar α-phase PVDF to polar β-phase. The above multi-functionality of the composite films of PVDF-Fe3O4 and PVDF-GO-Fe3O4 paves the way for their application in smart multiferroic devices.

  13. Fabrication of flexible and self-standing inorganic-organic three phase magneto-dielectric PVDF based multiferroic nanocomposite films through a small loading of graphene oxide (GO) and Fe3O4 nanoparticles.

    PubMed

    Jayakumar, O D; Abdelhamid, Ehab H; Kotari, Vasundhara; Mandal, Balaji P; Rao, Rekha; Jagannath; Naik, Vaman M; Naik, Ratna; Tyagi, A K

    2015-09-28

    Flexible inorganic-organic magneto-electric (ME) nanocomposite films (PVDF, PVDF-GO, PVDF-Fe3O4 and PVDF-GO-Fe3O4), composed of well-dispersed graphene oxide (GO 5 wt%) and magnetic Fe3O4 nanoparticles (5 wt%) embedded into a poly(vinylidene-fluoride) (PVDF) matrix, have been prepared by a solvent casting route. The magnetic, ferroelectric, dielectric, magneto-dielectric (MD) coupling and structural properties of these films have been systematically investigated. Magnetic (Ms = 2.21 emu g(-1)) and ferroelectric (P = 0.065 μC cm(-2)) composite films of PVDF-GO-Fe3O4 (PVDF loaded with 5% GO and 5% Fe3O4) with an MD coupling of 0.02% at room temperature (RT) showed a three times higher dielectric constant than that of the pure PVDF film, with a dielectric loss as low as 0.6. However, the PVDF-Fe3O4 film, which exhibited improved magnetic (Ms = 2.5 emu g(-1)) and MD coupling (0.04%) properties at RT with a lower dielectric loss (0.3), exhibited decreased ferroelectric properties (P = 0.06 μC cm(-2)) and dielectric constant compared to the PVDF-GO-Fe3O4 film. MD coupling measurements carried out as a function of temperature on the multi-functional PVDF-GO-Fe3O4 film showed a systematic increase in MD values up to 100 K and a decrease thereafter. The observed magnetic, ferroelectric, dielectric, MD coupling and structural properties of the nanocomposite films are attributed to the homogeneous dispersion and good alignment of Fe3O4 nanoparticles and GO in the PVDF matrix along with a partial conversion of nonpolar α-phase PVDF to polar β-phase. The above multi-functionality of the composite films of PVDF-Fe3O4 and PVDF-GO-Fe3O4 paves the way for their application in smart multiferroic devices. PMID:26274764

  14. Experimental constraints on the interaction between hydrous and anhydrous magmas at Stromboli volcano.

    NASA Astrophysics Data System (ADS)

    Pompilio, M.

    2008-12-01

    Triggers of eruptions or important changes in eruptive style have been often associated to the arrival of batches of new undegassed magma in the volcanic plumbing system. This process has been proved to occur in basaltic and in more evolved magma. What happen in a magmatic reservoir and how do melts interact when this occur has been theoretical inferred or modeled using silicate analogues, thermodynamics or numerically. But only few laboratory experiments on molten silicates exist. Analogues of magmas, as syrups or waxes allow scaling of some important parameters like density contrast, rheology, and relative proportion between volumes of the interacting melts, but some other important process like diffusion, crystallization and gas exsolution is overlooked. These processes can significantly affect the mobility of magmas and the extent of mixing. This paper reports main results of laboratory experiments carried at high pressure and temperature on natural melts aimed to reproduce interaction between hydrous and dry magmas with same compositions. A grounded basalt from Stromboli is used as starting material in order gain insights on the dynamics of magmas within the plumbing system. In fact the interaction between hydrous crystal-poor and dry crystal-rich magmas is recognized to trigger violent paroxysmal eruptions in this volcano. A dry glassy (or slightly crystallized) cylinder was superimposed to an hydrous grounded glass in a single Au- Pd capsule. Charges were held for between 15 minutes and 13 hours at about 1130°C , 50 Mpa in a EHPV and then rapidly quenched isobarically. Capsules were cut longitudinally and interactions between melts were observed by SEM, EMP and FTIR. Results evidence that in runs with shorter duration (<1 hour) water diffusion dominates at the interface and strongly controls liquidus temperature, crystallization and rheology. Experiments of longer duration show buoyant plumes or blobs of water-rich melts that rise and mix with the

  15. Geochemical changes and fracture development in Woodford Shale cores following hydrous pyrolysis under uniaxial confinement

    USGS Publications Warehouse

    Birdwell, Justin E.; Lewan, Michael D.; Miller, Michael; Baez, Luis; Beeney, Ken; Sonnenberg, Steve

    2013-01-01

    A uniaxial confinement clamp was used on Woodford Shale cores in hydrous pyrolysis experiments to study fracture development during thermal maturation. The clamp simulates overburden in that it prevents cores from expanding perpendicular to bedding fabric during the volume-increasing reactions associated with petroleum generation. Cores were cut from a slab of immature Woodford Shale and subjected to hydrous pyrolysis under confinement at 300, 330, and 365 °C for 72 hours to induce thermal maturities ranging from early bitumen to maximum expelled-oil generation. Two additional cores were used as experimental controls: (1) a confined core was saturated with water by heating it to 100 °C under hydrous pyrolysis conditions for 72 hours to use for characterization of the original rock, and (2) an unconfined core was heated at 365 °C for 72 hours to evaluate the effects of confinement on petroleum generation and expulsion. X-ray computed tomography (X-CT) imaging and other analyses identified five distinct beds within the cored interval. Using a tentative classification system, beds 1, 2, and 3 are described as dolomitic marlstone (DM) with total organic carbon (TOC) contents of 7.7, 5.8, and 7.7 wt. %, respectively; bed 4 is a cherty quartzose claystone (CQC) with TOC content of 5.5 wt. %; and bed 5 is a quartzose claystone with TOC content of 10.9 wt. %. Bed samples all had similar Rock-Eval hydrogen indices (600 ± 46 mg S2/g-TOC) and Tmax values (433 ± 2 °C), demonstrating organic matter uniformity and low thermal maturity. The X-CT scan of the core heated to 100 °C showed preexisting fractures that were nearly perpendicular to the bedding fabric primarily in the low-TOC DM bed 2 and CQC bed 4. Heating led to enhancement of preexisting fractures in the confined cores with the greatest enhancement occurring in CQC bed 4. The fractures increased in size and intensity with temperature. This is attributed to the internal pressure generated by volume

  16. High-pressure and high-temperature stability field of hydrous phase delta-AlOOH

    NASA Astrophysics Data System (ADS)

    Sano, A.; Ohtani, E.; Kondo, T.; Hirao, N.; Sone, T.; Kikegawa, T.; Sata, N.; Ohishi, Y.

    2005-12-01

    Stability field of hydrous phases is a key for understanding water concentration in the earth's mantle. δ-AlOOH is a high-pressure polymorph of diaspore (α-AlOOH) and boehmite (γ-AlOOH). The space group of this phase is Pnn2 and it is similar to CaCl2-type SiO2 which is a high-pressure polymorph of stishovite; edge-sharing Al-O octahedra make single-chain along c-axis. Although it has a large stability field in pressure range from 18 GPa to 32 GPa and temperature of up to 1473 K, the high-pressure stability limits has not yet clarified. In this study, we investigated the stability field of δ-AlOOH up to 130 GPa. The high-pressure experiments were performed using a laser-heated diamond-anvil cell. Starting material was gibbsite (Al(OH)3) powder mixed with platinum black as a laser absorber. The sample was sandwiched by pure gibbsite layers and loaded into a rhenium gasket. Pressures were measured with ruby-fluorescence technique before and after heating. The sample was heated from both sides by a Nd:YAG laser operated in multimode. After experiment, stable phase in each condition was determined using the X-ray diffraction and Raman spectroscopy method. We also conducted in-situ X-ray diffraction experiments under high-pressure and temperature conditions together with the X-ray diffraction of the recovered samples both at BL10XU in SPring-8 and BL-13A in Photon Factory. In these runs, pressures were also calculated using the equation of state of platinum. The experimental conditions were in the pressures between 50-130 GPa and temperatures to 1800 K. X-ray analysis shows the sample recovered from the pressure and temperature range from 40 GPa and 1577 K to 130 GPa and 1800 K consists of δ-AlOOH. In the in-situ experiments, crystallization of δ-AlOOH was observed at 65 GPa and 1300 K and it was stable up to 1700 K. δ-AlOOH is stable in the large pressure range with a dehydration temperature around 1800K. It can be a water reservoir in subducting slabs in the

  17. The Origin of Hydrous Minerals in Peridotite Mylonites from an Oceanic Transform Fault

    NASA Astrophysics Data System (ADS)

    Deems, N. J.; Warren, J. M.; McCubbin, F. M.; Wolfson-Schwehr, M.

    2014-12-01

    Previous studies of oceanic transform faults have assumed that fluid circulation ends when the transition from brittle failure to plastic flow occurs. However, we have identified significant amounts of hydrous minerals in peridotite mylonites from St. Paul's Rocks, a small set of islets on the St. Paul Transform Fault on the Mid-Atlantic Ridge. These rocks, which are highly deformed, are interpreted as having originated within the brittle-ductile transition zone. Our analyses show that the peridotites contain syn-deformational amphibole (12% on average) and minor phlogopite. In addition, the mylonites contain cm-scale veins of gabbro that are semi-parallel to foliation, which have been altered to amphibole, sodalite, and scapolite. Microprobe analysis indicates that the amphibole is pargasite, which is relatively rich in Na and Cl and requires temperatures >~700°C to form. In addition, sodalite and scapolite contain Na and Cl as essential elements. Initial stable isotope analysis indicates that δD of the pargasite lies between mantle δD (~70‰) and seawater (0‰). Based on our observations, we suggest that melt was introduced into the system either prior to or during deformation. In addition, we propose that either i) the melt was volatile-rich, providing the necessary water to form hydrous phases; or ii) seawater penetrated into the brittle-ductile transition zone by microfracturing, thus providing the necessary water, Na, and Cl to form the phases observed. While the 600°C isotherm is traditionally considered the limit of brittle deformation, this second hypothesis would suggest that seawater can penetrate to greater depths, in agreement with recent seismicity observations from an East Pacific Rise transform fault (McGuire et al., 2012). With additional stable isotope analysis and thermodynamic modeling, we plan to further constrain the source of melt/fluid at St. Paul's Rocks and thus improve constraints on OTF processes. If seawater is the origin of syn

  18. Inorganic Crystal Structure Database (ICSD)

    National Institute of Standards and Technology Data Gateway

    SRD 84 FIZ/NIST Inorganic Crystal Structure Database (ICSD) (PC database for purchase)   The Inorganic Crystal Structure Database (ICSD) is produced cooperatively by the Fachinformationszentrum Karlsruhe(FIZ) and the National Institute of Standards and Technology (NIST). The ICSD is a comprehensive collection of crystal structure data of inorganic compounds containing more than 140,000 entries and covering the literature from 1915 to the present.

  19. Periodicity in the Acid-Base Behavior of Oxides and Hydroxides.

    ERIC Educational Resources Information Center

    Rich, Ronald L.

    1985-01-01

    Aqueous solubilities of many important hydrous oxides and hydroxides are displayed, for the various elements, as functions primarily of pH. These graphs are then arranged in groups to facilitate studies of the effects of oxidation state, electron structure, and position in the periodic table, along with size and coordination number. (JN)

  20. Inorganic chemically active adsorbents (ICAAs)

    SciTech Connect

    Ally, M.R.; Tavlarides, L.

    1997-10-01

    Oak Ridge National Laboratory (ORNL) researchers are developing a technology that combines metal chelation extraction technology and synthesis chemistry. They begin with a ceramic substrate such as alumina, titanium oxide or silica gel because they provide high surface area, high mechanical strength, and radiolytic stability. One preparation method involves silylation to hydrophobize the surface, followed by chemisorption of a suitable chelation agent using vapor deposition. Another route attaches newly designed chelating agents through covalent bonding by the use of coupling agents. These approaches provide stable and selective, inorganic chemically active adsorbents (ICAAs) tailored for removal of metals. The technology has the following advantages over ion exchange: (1) higher mechanical strength, (2) higher resistance to radiation fields, (3) higher selectivity for the desired metal ion, (4) no cation exchange, (5) reduced or no interference from accompanying anions, (6) faster kinetics, and (7) easy and selective regeneration. Target waste streams include metal-containing groundwater/process wastewater at ORNL`s Y-12 Plant (multiple metals), Savannah River Site (SRS), Rocky Flats (multiple metals), and Hanford; aqueous mixed wastes at Idaho National Engineering Laboratory (INEL); and scrubber water generated at SRS and INEL. Focus Areas that will benefit from this research include Mixed Waste, and Subsurface Contaminants.

  1. Inventory of H2O in the ancient Martian regolith from Northwest Africa 7034: The important role of Fe oxides

    NASA Astrophysics Data System (ADS)

    Muttik, Nele; McCubbin, Francis M.; Keller, Lindsay P.; Santos, Alison R.; McCutcheon, Whitney A.; Provencio, Paula P.; Rahman, Zia; Shearer, Charles K.; Boyce, Jeremy W.; Agee, Carl B.

    2014-12-01

    Water-rich Martian regolith breccia Northwest Africa (NWA) 7034 was analyzed by Fourier transform infrared spectroscopy and transmission electron microscopy to determine the inventory and phase distribution of H2O (used herein to refer to both molecular H2O and OH- structural components in hydrous minerals). Hydrous Fe oxide phases (hydromaghemite and an unidentified nanocrystalline Fe-bearing oxide phase observed with hydromaghemite) and phyllosilicates (saponite) were identified as the primary mineralogic hosts for H2O with a minor contribution from Cl-rich apatite. Based on mass balance calculations and modal abundances of minerals constrained by powder X-ray diffraction and petrography, we can account for the entire 6000 ppm H2O measured in bulk rock analyses of NWA 7034. This H2O is distributed evenly between hydrous Fe-rich oxides and phyllosilicates, indicating that Fe oxides could be as important as phyllosilicates for H2O storage in Martian surface material.

  2. Optimization of hydrous ferrous sulfate dehydration by microwave heating using response surface methodology.

    PubMed

    Yu, Yan-Tao; Liu, Bing-Guo; Chen, Guo; Peng, Jin-Hui; Srinivasakannan, C

    2012-01-01

    The work relates to assessing the ability of the microwave for dehydration of large amount of waste hydrous ferrous sulfate generated from the titanium pigment process industry. The popular process optimization tool of response surface methodology with central composite design was adopted to estimate the effect of dehydration. The process variables were chosen to be power input, duration of heating and the bed thickness, while the response variable being the weight loss. An increase in all the three process variables were found to significantly increase the weight loss, while the effect of interaction among the parameters were found to be insignificant. The optimized process conditions that contribute to the maximum weight loss were identified to be a power input of 960 W, duration of heating of 14 min and bed thickness of 5 cm, resulting in a weight loss of 31.44%. The validity of the optimization process was tested with the repeat runs at optimized conditions.

  3. A hydrous Ca-bearing magnesium carbonate from playa lake sediments, Salines Lake, Spain

    USGS Publications Warehouse

    Queralt, I.; Julia, R.; Plana, F.; Bischoff, J.L.

    1997-01-01

    Sediments of playa Lake Salines, SE, Spain, contain a carbonate mineral characterized by X-ray diffraction peaks very similar to, but systematically shifted from those of pure magnesite. Analyses (SEM, IR and Raman spectroscopy, DTA, TGA, and ICP) indicate the mineral is a hydrous Ca-bearing magnesium carbonate with the chemical formula (Mg0.92,Ca0.08)CO3??3H2O. Thermal characteristics of the mineral are similar to those of other known hydrated magnesium carbonates. X-ray and electron diffraction data suggests a monoclinic system (P21/n space group) with unit-cell parameters of a = 6.063(6), b = 10.668(5), and c = 6.014(4) A?? and ?? = 107.28??.

  4. Microwave-assisted synthesis of carbon-supported carbides catalysts for hydrous hydrazine decomposition

    NASA Astrophysics Data System (ADS)

    Mnatsakanyan, Raman; Zhurnachyan, Alina R.; Matyshak, Valery A.; Manukyan, Khachatur V.; Mukasyan, Alexander S.

    2016-09-01

    Microwave-assisted synthesis of carbon-supported Mo2C and WC nanomaterials was studied. Two different routes were utilized to prepare MoO3 (WO3) - C precursors that were then subjected to microwave irradiation in an inert atmosphere. The effect of synthesis conditions, such as irradiation time and gas environment, was investigated. The structure and formation mechanism of the carbide phases were explored. As-synthesized nanomaterials exhibited catalytic activity for hydrous hydrazine (N2H4·H2O) decomposition at 30-70 °C. It was shown that the catalyst activity significantly increases if microwave irradiation is applied during the decomposition process. Such conditions permit complete conversion of hydrazine to ammonia and nitrogen within minutes. This effect can be attributed to the unique nanostructure of the catalysts that includes microwave absorbing carbon and active carbide constituents.

  5. Can Hydrous Minerals Account for the Observed Mid-Latitude Water on Mars?

    NASA Technical Reports Server (NTRS)

    Bish, D. L.; Vaniman, D. T.; Fialips, C.; Carey, J. W.; Feldman, W. C.

    2003-01-01

    Clays, zeolites, and Mg-sulfates are all phases that could potentially retain H2O in martian regolith. The nature of the hydrogen-containing material observed in the equatorial martian regolith is of particular importance to the question of whether hydrous minerals have formed in the past on Mars. Also, whether these minerals exist in a hydrated (i.e., containing H2O molecules in their structures) or dehydrated state is a crucial question. The purpose of this communication is to estimate the possible magnitude of the H2O reservoir constituted by these H2O-bearing minerals. In other words, can minerals containing H2O and/or OH such clays, zeolites, or Mg-sulfates, reasonably be expected to account for the amounts of near-equatorial H2O-equivalent hydrogen recently documented by Mars Odyssey?

  6. Inorganic-organic composite solid polymer electrolytes

    SciTech Connect

    Abraham, K.M.; Koch, V.R.; Blakley, T.J.

    2000-04-01

    Inorganic-organic composite solid polymer electrolytes (CSPEs) have been prepared from the poly(ethylene oxide) (PEO)-like electrolytes of the general formula polyvinylidene fluoride-hexafluoropropylene (PVdF-HFP)-PEO{sub n}-LiX and Li{sup +}-conducting ceramic powders. In the PEO-like electrolytes, PVdF-HFP is the copolymer of PVdF and HFP, PEO{sub n} is a nonvolatile oligomeric polyethylene oxide of {approximately}400 g/mol molecular weight, and LiX is lithium bis(trifluoroethylsulfonyl)imide. Two types of inorganic oxide ceramic powders were used: a highly Li{sup +}-conducting material of the composition 14 mol % Li{sub 2}O-9Al{sub 2}O{sub 3}-38TiO{sub 2}-39P{sub 2}O{sub 5}, and the poorly Li{sup +}-conducting Li-silicates Li{sub 4{minus}x}M{sub x}SiO{sub 4} where M is Ca or Mg and x is 0 or 0.05. The composite electrolytes can be prepared as thin membranes in which the Li{sup +} conductivity and good mechanical strength of the Li{sup +}-conducting inorganic ceramics are complemented by the structural flexibility and high conductivity of organic polymer electrolytes. Excellent electrochemical and thermal stabilities have been demonstrated for the electrolyte films. Li//composite electrolyte//LiCoO{sub 2} rechargeable cells have been fabricated and cycled at room temperature and 50 C.

  7. Hunting for hydrogen: random structure searching and prediction of NMR parameters of hydrous wadsleyite.

    PubMed

    Moran, Robert F; McKay, David; Pickard, Chris J; Berry, Andrew J; Griffin, John M; Ashbrook, Sharon E

    2016-04-21

    The structural chemistry of materials containing low levels of nonstoichiometric hydrogen is difficult to determine, and producing structural models is challenging where hydrogen has no fixed crystallographic site. Here we demonstrate a computational approach employing ab initio random structure searching (AIRSS) to generate a series of candidate structures for hydrous wadsleyite (β-Mg2SiO4 with 1.6 wt% H2O), a high-pressure mineral proposed as a repository for water in the Earth's transition zone. Aligning with previous experimental work, we solely consider models with Mg3 (over Mg1, Mg2 or Si) vacancies. We adapt the AIRSS method by starting with anhydrous wadsleyite, removing a single Mg(2+) and randomly placing two H(+) in a unit cell model, generating 819 candidate structures. 103 geometries were then subjected to more accurate optimisation under periodic DFT. Using this approach, we find the most favourable hydration mechanism involves protonation of two O1 sites around the Mg3 vacancy. The formation of silanol groups on O3 or O4 sites (with loss of stable O1-H hydroxyls) coincides with an increase in total enthalpy. Importantly, the approach we employ allows observables such as NMR parameters to be computed for each structure. We consider hydrous wadsleyite (∼1.6 wt%) to be dominated by protonated O1 sites, with O3/O4-H silanol groups present as defects, a model that maps well onto experimental studies at higher levels of hydration (J. M. Griffin et al., Chem. Sci., 2013, 4, 1523). The AIRSS approach adopted herein provides the crucial link between atomic-scale structure and experimental studies. PMID:27020937

  8. Hydrous partial melting in the lower crust of the Oman ophiolite

    NASA Astrophysics Data System (ADS)

    Boudier, F. I.; Koepke, J.; Nicolas, A. J.

    2004-12-01

    Series of water-saturated melting experiments have been performed on natural gabbros between 900° and 1000°C, at crustal pressure up to 200MPa (Koepke et al., 2004), that put new constraints on the composition of melt and residual crystals at increasing temperature and melt fraction produced. In the gabbro section of the Oman ophiolite, the development of high-T secondary parageneses is ubiquist, represented by orthopyroxene+pargasite rims within contact between olivine and plagioclase, while clinopyroxene is replaced by pargasite. The reference to the experimental results, and isotopic tracing (Bosch et al., 2004) lead to interpret these reactions as representing initiation of hydrous partial melting by fluids circulating at grain boundaries. The inferred mechanism allowing supercritical water to penetrate the deep gabbro section is a strong anisotropy of thermal compression inducing microcracking in the cooling lower gabbros (Nicolas et al., 2003). In the Oman gabbros, another important petrologic feature is the local occurrence, in the deeper section, of large amounts of orthopyroxene bearing gabbros either interlayered with olivine gabbros or intrusive as pegmatitic patches, in association with wehrlites, or mixed with pargasitic gabbros. The corresponding upper levels are rich in dioritic or trondjemitic dikes. These occurrences are restricted to localized areas that coincide with tips and segments limits as deduced from the detailed mapping along the NW-SE paleospreading axis. The origin of these parageneses as products of hydrous melting of the gabbros, at various melt fraction, is explored by reference to the experimental data. Koepke, J., Feig, S.T., Snow, J., Freise, M., 2004. Contrib. Mineral. Petrol. 146, 414-432. Bosch, D.et al., 2004, J. Petrology, 45, 1181-1208. Nicolas, A., Mainprice, D., Boudier, F., 2003, J. Geophys. Res. 108 (B8) 2371.

  9. Characterizing thermogenic coalbed gas from Polish coals of different ranks by hydrous pyrolysis

    USGS Publications Warehouse

    Kotarba, M.J.; Lewan, M.D.

    2004-01-01

    To provide a better characterization of origin and volume of thermogenic gas generation from coals, hydrous pyrolysis experiments were conducted at 360??C for 72 h on Polish coals ranging in rank from lignite (0.3% R r) to semi-anthracite (2.0% Rr). Under these conditions, the lignites attained a medium-volatile bituminous rank (1.5% Rr), high-volatile bituminous coals attained a low-volatile bituminous rank (1.7% Rr), and the semi-anthracite obtained an anthracite rank (4.0% R r). Hydrous pyrolysis of a coal, irrespective of rank, provides a diagnostic ??13C value for its thermogenic hydrocarbon gases. This value can be used quantitatively to interpret mixing of indigenous thermogenic gas with microbial methane or exogenous thermogenic gas from other sources. Thermogenic methane quantities range from 20 dm3/kg of lignite (0.3% Rr) to 0.35 dm3/kg of semi-anthracite (2.0% Rr). At a vitrinite reflectance of 1.7% Rr, approximately 75% of the maximum potential for a coal to generate thermogenic methane has been expended. At a vitrinite reflectance of 1.7% Rr, more than 90% of the maximum potential for a coal to generate CO2 has been expended. Assuming that these quantities of generated CO2 remain associated with a sourcing coal bed as uplift or erosion provide conditions conducive for microbial methanogenesis, the resulting quantities of microbial methane generated by complete CO2 reduction can exceed the quantities of thermogenic methane generated from the same coal bed by a factor of 2-5. ?? 2004 Elsevier Ltd. All rights reserved.

  10. Hunting for hydrogen: random structure searching and prediction of NMR parameters of hydrous wadsleyite.

    PubMed

    Moran, Robert F; McKay, David; Pickard, Chris J; Berry, Andrew J; Griffin, John M; Ashbrook, Sharon E

    2016-04-21

    The structural chemistry of materials containing low levels of nonstoichiometric hydrogen is difficult to determine, and producing structural models is challenging where hydrogen has no fixed crystallographic site. Here we demonstrate a computational approach employing ab initio random structure searching (AIRSS) to generate a series of candidate structures for hydrous wadsleyite (β-Mg2SiO4 with 1.6 wt% H2O), a high-pressure mineral proposed as a repository for water in the Earth's transition zone. Aligning with previous experimental work, we solely consider models with Mg3 (over Mg1, Mg2 or Si) vacancies. We adapt the AIRSS method by starting with anhydrous wadsleyite, removing a single Mg(2+) and randomly placing two H(+) in a unit cell model, generating 819 candidate structures. 103 geometries were then subjected to more accurate optimisation under periodic DFT. Using this approach, we find the most favourable hydration mechanism involves protonation of two O1 sites around the Mg3 vacancy. The formation of silanol groups on O3 or O4 sites (with loss of stable O1-H hydroxyls) coincides with an increase in total enthalpy. Importantly, the approach we employ allows observables such as NMR parameters to be computed for each structure. We consider hydrous wadsleyite (∼1.6 wt%) to be dominated by protonated O1 sites, with O3/O4-H silanol groups present as defects, a model that maps well onto experimental studies at higher levels of hydration (J. M. Griffin et al., Chem. Sci., 2013, 4, 1523). The AIRSS approach adopted herein provides the crucial link between atomic-scale structure and experimental studies.

  11. Variation of the shape and morphological properties of silica and metal oxide powders by electro homogeneous precipitation

    DOEpatents

    Harris, Michael T.; Basaran, Osman A.; Sisson, Warren G.; Brunson, Ronald R.

    1997-01-01

    The present invention provides a method for preparing irreversible linear aggregates (fibrils) of metal oxide powders by utilizing static or pulsed DC electrical fields across a relatively non-conducting liquid solvent in which organometal compounds or silicon alkoxides have been dissolved. The electric field is applied to the relatively non-conducting solution throughout the particle formation and growth process promoting the formation of either linear aggregates (fibrils) or spherical shaped particles as desired. Thus the present invention provides a physical method for altering the size, shape and porosity of precursor hydrous metal oxide or hydrous silicon oxide powders for the development of advanced ceramics with improved strength and insulating capacity.

  12. Inorganic polymer engineering materials

    SciTech Connect

    Stone, M.L.

    1993-06-01

    Phosphazene-based, inorganic-polymer composites have been produced and evaluated as potential engineering materials. The thermal, chemical, and mechanical properties of several different composites made from one polymer formulation have been measured. Measured properties are very good, and the composites show excellent promise for structural applications in harsh environments. Chopped fiberglass, mineral, cellulose, and woodflour filled composites were tested. Chopped fiberglass filled composites showed the best overall properties. The phosphazene composites are very hard and rigid. They have low dielectric constants and typical linear thermal expansion coefficients for polymers. In most cases, the phosphazene materials performed as well or better than analogous, commercially available, filled phenolic composites. After 3 to 5 weeks of exposure, both the phosphazene and phenolics were degraded to aqueous bases and acids. The glass filled phosphazene samples were least affected.

  13. Selective inorganic thin films

    SciTech Connect

    Phillips, M.L.F.; Weisenbach, L.A.; Anderson, M.T.

    1995-05-01

    This project is developing inorganic thin films as membranes for gas separation applications, and as discriminating coatings for liquid-phase chemical sensors. Our goal is to synthesize these coatings with tailored porosity and surface chemistry on porous substrates and on acoustic and optical sensors. Molecular sieve films offer the possibility of performing separations involving hydrogen, air, and natural gas constituents at elevated temperatures with very high separation factors. We are focusing on improving permeability and molecular sieve properties of crystalline zeolitic membranes made by hydrothermally reacting layered multicomponent sol-gel films deposited on mesoporous substrates. We also used acoustic plate mode (APM) oscillator and surface plasmon resonance (SPR) sensor elements as substrates for sol-gel films, and have both used these modified sensors to determine physical properties of the films and have determined the sensitivity and selectivity of these sensors to aqueous chemical species.

  14. PATHWAY OF INORGANIC ARSENIC METABOLISM

    EPA Science Inventory

    A remarkable aspect of the metabolism of inorganic arsenic in humans is its conversion to methylated metabolites. These metabolites account for most of the arsenic found in urine after exposure to inorganic arsenic. At least some of the adverse health effects attributed to inor...

  15. Development of taste sensing system using inorganic membrane

    NASA Astrophysics Data System (ADS)

    Kojima, Yohichiro; Hasegawa, Yuki

    2011-09-01

    We developed a novel taste sensor for liquid and verified its effectiveness using coffee. We fabricated an inorganic metal oxide membrane liquid sensor using the laser ablation method. The sensor shows a sufficient sensitivity for electrolyte solutions, while it shows a relatively low response for non-electrolyte solutions. We differentiated and identified five brands of commercially available coffee using the sensor.

  16. Ion-Conducting Organic/Inorganic Polymers

    NASA Technical Reports Server (NTRS)

    Kinder, James D.; Meador, Mary Ann B.

    2007-01-01

    Ion-conducting polymers that are hybrids of organic and inorganic moieties and that are suitable for forming into solid-electrolyte membranes have been invented in an effort to improve upon the polymeric materials that have been used previously for such membranes. Examples of the prior materials include perfluorosulfonic acid-based formulations, polybenzimidazoles, sulfonated polyetherketone, sulfonated naphthalenic polyimides, and polyethylene oxide (PEO)-based formulations. Relative to the prior materials, the polymers of the present invention offer greater dimensional stability, greater ease of formation into mechanically resilient films, and acceptably high ionic conductivities over wider temperature ranges. Devices in which films made of these ion-conducting organic/inorganic polymers could be used include fuel cells, lithium batteries, chemical sensors, electrochemical capacitors, electrochromic windows and display devices, and analog memory devices. The synthesis of a polymer of this type (see Figure 1) starts with a reaction between an epoxide-functionalized alkoxysilane and a diamine. The product of this reaction is polymerized by hydrolysis and condensation of the alkoxysilane group, producing a molecular network that contains both organic and inorganic (silica) links. The silica in the network contributes to the ionic conductivity and to the desired thermal and mechanical properties. Examples of other diamines that have been used in the reaction sequence of Figure 1 are shown in Figure 2. One can use any of these diamines or any combination of them in proportions chosen to impart desired properties to the finished product. Alternatively or in addition, one could similarly vary the functionality of the alkoxysilane to obtain desired properties. The variety of available alkoxysilanes and diamines thus affords flexibility to optimize the organic/inorganic polymer for a given application.

  17. Inorganic nanostructured materials for high performance electrochemical supercapacitors.

    PubMed

    Liu, Sheng; Sun, Shouheng; You, Xiao-Zeng

    2014-02-21

    Electrochemical supercapacitors (ES) are a well-known energy storage system that has high power density, long life-cycle and fast charge-discharge kinetics. Nanostructured materials are a new generation of electrode materials with large surface area and short transport/diffusion path for ions and electrons to achieve high specific capacitance in ES. This mini review highlights recent developments of inorganic nanostructure materials, including carbon nanomaterials, metal oxide nanoparticles, and metal oxide nanowires/nanotubes, for high performance ES applications.

  18. Carboranylphosphinic Acids: A New Class of Purely Inorganic Ligands.

    PubMed

    Oleshkevich, Elena; Teixidor, Francesc; Choquesillo-Lazarte, Duane; Sillanpää, Reijo; Viñas, Clara

    2016-03-01

    Purely inorganic carboranyl phosphinates were prepared, and the influence of the cluster on the reactivity of the phosphinate group was studied. Electron-withdrawal by the carboranyl carbon atoms, combined with space-filling efficiency and enhanced aromaticity of the cluster cage, renders the phosphorus more difficult to oxidize. This enables carboranyl phosphinates to survive harsh oxidizing conditions, a property which is uncommon in organic phosphinates. PMID:26638876

  19. Biomarker generation from Type II-S kerogens in claystone and limestone during hydrous and anhydrous pyrolysis

    USGS Publications Warehouse

    Koopmans, M.P.; Carson, F.C.; Sinninghe, Damste J.S.; Lewan, M.D.

    1998-01-01

    A claystone and a limestone containing immature Type II-S kerogen were thermally matured in the presence and absence of water, to study the influence of water and clay minerals on the generation of biomarkers. In contrast to hydrous pyrolysis, anhydrous pyrolysis of the claystone did not generate biomarkers, which resulted in the loss of important information. Desulfurization of the polar fraction of the claystone showed that anhydrous pyrolysis is not capable of converting S-bound biomarkers to free biomarkers. For the limestone, the differences between hydrous and anhydrous pyrolysis are less dramatic. Adsorption of the polar fraction of the claystone to smectite interlayers probably leads to cross-linking reactions, preventing the generation of free biomarkers. During hydrous pyrolysis, the smectite interlayers are occupied by water so that generation of biomarkers can take place. In addition, cross-linking reactions during anhydrous pyrolysis of the claystone may be enhanced because of the presence of S-S bonds in the organic matter of the claystone. These results show that water is important in closed system laboratory experiments designed to simulate natural maturation of sedimentary organic matter.A claystone and a limestone containing immature Type II-S kerogen were thermally matured in the presence and absence of water, to study the influence of water and clay minerals on the generation of biomarkers. In contrast to hydrous pyrolysis, anhydrous pyrolysis of the claystone did not generate biomarkers, which resulted in the loss of important information. Desulfurization of the polar fraction of the claystone showed that anhydrous pyrolysis is not capable of converting S-bound biomarkers to free biomarkers. For the limestone, the differences between hydrous and anhydrous pyrolysis are less dramatic. Adsorption of the polar fraction of the claystone to smectite interlayers probably leads to cross-linking reactions, preventing the generation of free biomarkers

  20. Significance of hydrous silicate lamellae in pyrope-rich garnets from the Garnet Ridge in the Colorado Plateau

    NASA Astrophysics Data System (ADS)

    Ogasawara, Y.; Sakamaki, K.; Sato, Y.

    2014-12-01

    Pyrope-rich garnets originated from the upper mantle underneath the Colorado Plateau occur at the Garnet Ridge. These garnets contain the following lamellae of hydrous and anhydrous minerals; Rt, Ilm, crichtonites, Cr-Spl, Amp, Cpx, Chl, rarely Apt, srilankite and carmichealite. The origin of these lamellae in the garnets is controversial; exsolved origin or epitaxial growth. We emphasize here the close relations between the presence of hydrous lamellae and the OH concentrations in the host garnets. Lamella phases were identified with a standard-less quantitative EDS system and a laser Raman spectrometer with Ar+ laser (514.5 nm). OH concentrations in garnets were quantitated on the basis of IR absorption spectra of garnet by micro FT-IR method using IR absorption coefficient (8770 L/mol/cm2, Katayama et al., 2006). Pyrope-rich reddish brown garnet (group B by Sato et al., AGU2014F) has large variations of major chemical compositions (Prp: 49-76, Alm: 6-43, Grs: 6-26 mol%), and OH contents (2-177 ppm wt. H2O). Among this group garnets, Ca-rich ones (Prp: 49-66; Alm: 18-28; Grs: 16-26 mol%) have lamellae of both hydrous (Amp and Chl) and anhydrous (Rt, Ilm, and Cpx) minerals. Amp and Chl lamellae are pargasitic amphibole and clinochlore, respectively, and their host garnets contain significantly low amounts of OH (2-42 ppm). Cr and pyrope-rich garnet (group A by Sato et al., AGU2014F) has chemical compositions of Prp: 67-74, Alm: 13-18, Grs: 7-11 mol% with Cr2O3 up to 5.9 wt.%, and contains lamellae of anhydrous minerals (Rt, Ilm, crichtonites, and Cr-Spl). The host garnet with these anhydrous lamellae contains a little higher OH ranging 24 to 115 ppm. Summarizing the present results, the OH contents of the host garnets depend on the presence of hydrous silicate lamella phase; OH in the garnet with hydrous silicate lamellae is lower than that in the garnet with anhydrous lamellae. The precursor OH incorporated in the host garnet structure was exsolved as hydrous

  1. Polystyrene-poly(vinylphenol) copolymers as compatibilzers for organic-inorganic composites

    SciTech Connect

    Landry, C.J.T.; Coltrain, B.K.; Teegarden, D.M.

    1996-12-31

    Random, graft, and block copolymers of polystyrene (PS) and poly(4-vinylphenol) (PVPh), and PVPh homopolymer are shown to act as compatibilizers for incompatible organic-inorganic composite materials. The VPh component reacts, or interacts strongly with the polymerizing inorganic (titanium or zirconium) alkoxide. The organic components studied were PS, poly(vinyl methyl ether), and poly(styrene-co-acrylonitrile). The use of such compatibilizers provides a means of combining in situ polymerized inorganic oxides and hydrophobic polymers. This is seen as a reduction in the size of the dispersed inorganic phase and results in improved optical and mechanical properties.

  2. Cancer risk from inorganics

    SciTech Connect

    Swierenga, S.H.; Gilman, J.P.; McLean, J.R.

    1987-01-01

    Inorganic metals and minerals for which there is evidence of carcinogenicity are identified. The risk of cancer from contact with them in the work place, the general environment, and under conditions of clinical (medical) exposure is discussed. The evidence indicates that minerals and metals most often influence cancer development through their action as cocarcinogens. The relationship between the physical form of mineral fibers, smoking and carcinogenic risk is emphasized. Metals are categorized as established (As, Be, Cr, Ni), suspected (Cd, Pb) and possible carcinogens, based on the existing in vitro, animal experimental and human epidemiological data. Cancer risk and possible modes of action of elements in each class are discussed. Views on mechanisms that may be responsible for the carcinogenicity of metals are updated and analysed. Some specific examples of cancer risks associated with the clinical use of potentially carcinogenic metals and from radioactive pharmaceuticals used in therapy and diagnosis are presented. Questions are raised as to the effectiveness of conventional dosimetry in accurately measuring risk from radiopharmaceuticals. 302 references.

  3. Inorganic ion sorbent method

    DOEpatents

    Teter, David M.; Brady, Patrick V.; Krumhansl, James L.

    2007-07-17

    A process and medium for decontamination of water containing anionic species including arsenic and chromium, wherein compounds comprising divalent and trivalent metal oxides and sulfides are used to form surface complexes with contaminants under pH conditions within the range of potable water. In one embodiment natural and synthetic spinels and spinel-like materials are used as the sorbent substance.

  4. Inorganic ion sorbents

    DOEpatents

    Teter, David M.; Brady, Patrick V.; Krumhansl, James L.

    2006-10-17

    A process and medium for decontamination of water containing anionic species including arsenic and chromium, wherein compounds comprising divalent and trivalent metal oxides and sulfides are used to form surface complexes with contaminants under pH conditions within the range of potable water. In one embodiment natural and synthetic spinels and spinel-like materials are used as the sorbent substance.

  5. A comparison of organic and inorganic nitrates/nitrites.

    PubMed

    Omar, Sami A; Artime, Esther; Webb, Andrew J

    2012-05-15

    Although both organic and inorganic nitrates/nitrites mediate their principal effects via nitric oxide, there are many important differences. Inorganic nitrate and nitrite have simple ionic structures and are produced endogenously and are present in the diet, whereas their organic counterparts are far more complex, and, with the exception of ethyl nitrite, are all medicinally synthesised products. These chemical differences underlie the differences in pharmacokinetic properties allowing for different modalities of administration, particularly of organic nitrates, due to the differences in their bioavailability and metabolic profiles. Whilst the enterosalivary circulation is a key pathway for orally ingested inorganic nitrate, preventing an abrupt effect or toxic levels of nitrite and prolonging the effects, this is not used by organic nitrates. The pharmacodynamic differences are even greater; while organic nitrates have potent acute effects causing vasodilation, inorganic nitrite's effects are more subtle and dependent on certain conditions. However, in chronic use, organic nitrates are considerably limited by the development of tolerance and endothelial dysfunction, whereas inorganic nitrate/nitrite may compensate for diminished endothelial function, and tolerance has not been reported. Also, while inorganic nitrate/nitrite has important cytoprotective effects against ischaemia-reperfusion injury, continuous use of organic nitrates may increase injury. While there are concerns that inorganic nitrate/nitrite may induce carcinogenesis, direct evidence of this in humans is lacking. While organic nitrates may continue to dominate the therapeutic arena, this may well change with the increasing recognition of their limitations, and ongoing discovery of beneficial effects and specific advantages of inorganic nitrate/nitrite.

  6. The compositions of Hydrous Fluids in equilibrium with the Peridotitic Mantle

    NASA Astrophysics Data System (ADS)

    Adam, J.; Locmelis, M.; Fiorentini, M.; Rushmer, T. A.

    2013-12-01

    The compositional characteristics of H2O-rich fluids are critical to determine because migrating hydrous fluids have the capacity to impart many of the compositional characteristics of arc magmas and the continental crust/hydrosphere, to mantle source regions. However, the compositions of H2O-fluids produced by near-solidus experiments on peridotite are intrinsically difficult to determine. In this study we avoided many previously encountered problems by using an indirect approach. This involved H2O-saturated experiments on a hydrous nepheline basanite for which conditions of equilibrium with garnet-lherzolite (~ 1200 °C and 2.6 GPa) had been independently established using near-liquidus phase equilibria. Following experiments in single Ag70Pd30 and Au capsules, the quenched products of melts and H2O-fluids could be easily distinguished and directly analysed by EDS and LAM ICP-MS. Solute concentrations in the fluid phase were then calculated from mass-balances using estimated H2O-solubilities in melts. Because mineral/melt partition coefficients had already been determined for trace and minor elements in the basanite, we indirectly obtained peridotite/fluid partition coefficients for the same elements. In addition, we were able to directly analyse co-existing fluid-solutes and peridotite phases (clinopyroxene + orthopyroxene + olivine + amphibole + mica + spinel) from one sub-solidus experiment at 950 °C and 2.0 GPa. At 2.0 GPa and 950-1100 °C the H2O-fluid contains between 10 and 20 wt. % of dissolved solute, which has a peralkaline phonolite composition. Relative to the co-existing basanite melt, the H2O-fluid is enriched in Cs, Rb, K, Pb, Ba and V, but otherwise has lower concentrations of most incompatible elements. It is not depleted in HFSE relative to REE. As pressure and temperature increase, the fluid becomes more solute-rich until at 4.0 GPa and 1100 °C no clear distinction between the fluid and melt phase is apparent. At 2-3 GPa and 1100

  7. Water on Mars: Clues from Deuterium/Hydrogen and Water Contents of Hydrous Phases in SNC Meteorites.

    PubMed

    Watson, L L; Hutcheon, I D; Epstein, S; Stolper, E M

    1994-07-01

    Ion microprobe studies of hydrous amphibole, biotite, and apatite in shergottite-nakhlite-chassignite (SNC) meteorites, probable igneous rocks from Mars, indicate high deuterium/hydrogen (D/H) ratios relative to terrestrial values. The amphiboles contain roughly one-tentn as much water as expected, suggesting that SNC magmas were less hydrous than previously proposed. The high but variable D/H values of these minerals are best explained by postcrystallization D enrichment of initially D-poor phases by martian crustal fluids with near atmospheric D/H (about five times the terrestrial value). These igneous phases do not directly reflect the D/H ratios of martian "magmatic" water but provide evidence for a D-enriched martian crustal water reservoir.

  8. Origin of hydrous fluids at seismogenic depth: Constraints from natural and experimental fault rocks

    NASA Astrophysics Data System (ADS)

    Mittempergher, Silvia; Dallai, Luigi; Pennacchioni, Giorgio; Renard, François; Di Toro, Giulio

    2014-01-01

    Fluids control the mechanical behavior of fault zones during the seismic cycle. We used geochemical, mineralogical, microstructural, hydrogen isotope compositions and Fourier Transform Infrared (FTIR) investigations to characterize the origin of hydrous fluids involved in ductile and brittle shear zones at the bottom of the seismogenic crust. Natural samples were collected from exhumed mylonitic shear zones and cataclasite-pseudotachylyte bearing faults in the northern Adamello (Italian Southern Alps), which were active at 9-11 km depth. Pseudotachylytes, solidified coseismic friction-induced melts, testify to ancient seismogenic behavior of the faults. Natural pseudotachylytes were compared with artificial pseudotachylytes produced in high velocity friction experiments simulating seismic slip. Mylonites have mineralogical, elemental and hydrogen isotope compositions (-80‰<δD<-78‰) similar to the host tonalite (-77‰<δD<-73‰), within the analytical error of ±5‰. Cataclasites have instead mineralogical (chlorite, epidote, K-feldspar, no biotite), major and trace elements (enrichment in K2O, Ba, Rb; depletion in CaO, Na2O, SiO2) and hydrogen isotope (-69‰<δD<-60‰) compositions suggesting interactions with a crustal metamorphic fluid. Pseudotachylytes are composed of high temperature minerals (plagioclase, biotite, dmisteinbergite, cordierite, and scapolite) and have elemental compositions resulting from mixing of tonalite and cataclasite. Pseudotachylytes have complex microstructures, including: (i) microlitic domains, with well crystallized micrometric biotite, which have hydrogen isotope composition (-81‰<δD<-59‰) similar to cataclasites and tonalite; and (ii) cryptocrystalline domains, with poorly crystallized biotite, which have very high water content, release water upon heating at T>50 °C and have low δD value (-93‰). The hydrogen isotope composition of bulk samples is dominated by the composition of cryptocrystalline domains (-103

  9. Review of inorganic nitrogen transformations and effect of global climate change on inorganic nitrogen cycling in ocean ecosystems

    NASA Astrophysics Data System (ADS)

    Kim, Haryun

    2016-03-01

    Inorganic N transformations (nitrification, anaerobic ammonium oxidation, denitrification, and dissimilatory nitrate reduction to ammonium) are regulated by various biogeochemical factors linked either by the supply of electron acceptors and donors or by competition for electron acceptors. This review considers both the microbial community related to each process and the technical methods used to measure each process rate. With this background knowledge, this article summarizes how global climate change through increased pCO2, ocean acidification, deoxygenation and anthropogenic N deposition will alter oceanic N cycling, and finally emphasizes the need for comprehensive research on inorganic N transformation in marine ecosystems.

  10. First principle molecular dynamics simulation of hydrous modal basalt melt structure

    NASA Astrophysics Data System (ADS)

    Karki, B. B.; Bajgain, S. K.

    2012-12-01

    We have performed the first principle molecular dynamics simulation of hydrous model basalt to investigate its structural properties over wide ranges of pressure (0-100 GPa) and temperature (2200-6000 K) ranges. Our initial results show that all partial radial distribution functions represent well-defined peaks with decreased amplitudes compared to those in pure basalt liquid. The mean Si-O (Al-O) coordination number at the reference volume of 3422.47 Å3 is ~ 3.9 (4.8) at the ambient pressure and 3000 K. The coordination increases with increasing pressure but varies only a little with temperature though the abundances of various coordination species are highly sensitive to both pressure and temperature. We find that isolated structures of water component dominate in lower pressure, which consists of hydroxyl, water molecule, O-H-O bridging, and four-atom (O-H-O-H and H-O-H-O) groups. At higher pressures, extended structures (five or more O and H atoms) are formed. The effects of water on melt depolymerization, compressibility and dynamical properties will also be examined.

  11. Evolution of melt-vapor surface tension in silicic volcanic systems: Experiments with hydrous melts

    USGS Publications Warehouse

    Mangan, M.; Sisson, T.

    2005-01-01

    We evaluate the melt-vapor surface tension (??) of natural, water-saturated dacite melt at 200 MPa, 950-1055??C, and 4.8-5.7 wt % H2O. We experimentally determine the critical supersaturation pressure for bubble nucleation as a function of dissolved water and then solve for ?? at those conditions using classical nucleation theory. The solutions obtained give dacite melt-vapor surface tensions that vary inversely with dissolved water from 0.042 (??0.003) J m-2 at 5.7 wt% H2O to 0.060 (??0.007) J m-2 at 5.2 wt% H2O to 0.073 (??0.003) J m-2 at 4.8 wt% H2O. Combining our dacite results with data from published hydrous haplogranite and high-silica rhyolite experiments reveals that melt-vapor surface tension also varies inversely with the concentration of mafic melt components (e.g., CaO, FeOtotal, MgO). We develop a thermodynamic context for these observations in which melt-vapor surface tension is represented by a balance of work terms controlled by melt structure. Overall, our results suggest that cooling, crystallization, and vapor exsolution cause systematic changes in ?? that should be considered in dynamic modeling of magmatic processes.

  12. Deuterium isotopic exchangeability of resin and amber at low thermal stress under hydrous conditions

    NASA Astrophysics Data System (ADS)

    Gonzalez, G.; Tappert, R.; Wolfe, A. P.; Muehlenbachs, K.

    2012-04-01

    Hydrous deuterium-exchange experiments have shown that a significant fraction of the original D/H composition of bulk kerogens, bitumens and expelled oils may participate in isotopic exchange reactions during burial diagenesis. However, it is unknown to what extent plant-derived secondary metabolites, namely resins and their fossil counterpart amber, exchange hydrogen isotopes following their biosynthesis. This situation hinders the application of resin D/H measurements in paleoenvironmental reconstruction. Here, we assess explicitly hydrogen exchange in resins and ambers using a series of immersion experiments in deuterated (D-enriched) waters over a period of several months at several temperatures. We are especially interested in assessing whether significant H-isotopic exchange occurs between resins and meteoric waters during early thermal maturation and polymerization. At 90°C, equivalent to ~3km of burial in most diagenetic regimes, modern conifer and angiosperm resins have an average post-metabolic H exchange of 4.6%, compared to only 1.1% for mature, polymerized ambers. At 55°C the degree of exchange is considerably lower: 1.9% for resins and 0.6% for ambers. These results indicate that most D/H isotopic exchange occurs prior to polymerization reactions, thereby confirming that D/H measurements from amber constitute a potentially sensitive proxy for environmental change.

  13. First evidence of hydrous silicic fluid films around solid inclusions in gem-quality diamonds

    NASA Astrophysics Data System (ADS)

    Nimis, Paolo; Alvaro, Matteo; Nestola, Fabrizio; Angel, Ross J.; Marquardt, Katharina; Rustioni, Greta; Harris, Jeff W.; Marone, Federica

    2016-09-01

    Diamonds form from fluids or melts circulating at depth in the Earth's mantle. Analysis of these fluids is possible if they remain entrapped in the diamond during its growth, but this is rarely observed in gem-quality stones. We provide the first evidence that typical mineral inclusions in gem-quality diamonds from the Siberian and Kaapvaal cratons are surrounded by a thin film of hydrous silicic fluid of maximum thickness 1.5 μm. The fluid contains Si2O(OH)6, Si(OH)4, and molecular H2O and was identified using confocal micro-Raman spectroscopy and synchrotron-based X-ray tomographic microscopy. As the solid mineral inclusions have both peridotitic and eclogitic affinities and occur in two cratonic regions, our results demonstrate the strong connection between water-rich fluids and the growth of gem-quality lithospheric diamonds. The presence of the fluid films should be taken into account for a proper evaluation of H2O contents in the mantle based on H2O contents in solid inclusions and for a robust assessment of diamond formation pressures based on the residual pressures of the inclusions.

  14. High-temperature phase transition and local structure of a hydrous anorthoclase

    NASA Astrophysics Data System (ADS)

    Yang, Y.; Wang, Z. P.; Tian, Z. Z.; Xia, Q. K.; Li, G. W.

    2016-02-01

    The in situ Raman spectra of a hydrous anorthoclase at temperatures of 20-800 °C have been measured using a LABRAM-HR spectrometer and Linkam TS 1500 heating stage. The frequencies of modes at 54, 99, 130 and 162 cm-1 related to M-O vibrations decrease sharply and then increase drastically or keep steady at temperatures above 200 °C. A knee point can be clearly seen at about 200 °C for those modes. The frequency of the mode at 282 cm-1 shows little temperature dependence. However, for the two strongest modes at 471 and 512 cm-1, the frequencies decrease linearly with increasing temperature. From evolution of the frequencies of modes at 54, 99, 130 and 162 cm-1 with temperature, the following conclusions can be drawn: (1) The distance of the local M-O bond shortens rather than lengthens at temperatures above 200 °C; (2) The abrupt changes of the local structure of M site induce a collapse of the framework structure and displacive phase transition at 200 °C; and (3) The H atoms incorporated in anorthoclase are located at the M site. These results are indicative for the structure and properties of anorthoclase at deep earth conditions.

  15. Inorganic nitrite supplementation for healthy arterial aging

    PubMed Central

    DeVan, Allison E.; Fleenor, Bradley S.; Seals, Douglas R.

    2014-01-01

    Aging is the major risk factor for cardiovascular diseases (CVD). This is attributable primarily to adverse changes in arteries, notably, increases in large elastic artery stiffness and endothelial dysfunction mediated by inadequate concentrations of the vascular-protective molecule, nitric oxide (NO), and higher levels of oxidative stress and inflammation. Inorganic nitrite is a promising precursor molecule for augmenting circulating and tissue NO bioavailability because it requires only a one-step reduction to NO. Nitrite also acts as an independent signaling molecule, exerting many of the effects previously attributed to NO. Results of recent studies indicate that nitrite may be effective in the treatment of vascular aging. In old mice, short-term oral sodium nitrite supplementation reduces aortic pulse wave velocity, the gold-standard measure of large elastic artery stiffness, and ameliorates endothelial dysfunction, as indicated by normalization of NO-mediated endothelium-dependent dilation. These improvements in age-related vascular dysfunction with nitrite are mediated by reductions in oxidative stress and inflammation, and may be linked to increases in mitochondrial biogenesis and health. Increasing nitrite levels via dietary intake of nitrate appears to have similarly beneficial effects in many of the same physiological and clinical settings. Several clinical trials are being performed to determine the broad therapeutic potential of increasing nitrite bioavailability on human health and disease, including studies related to vascular aging. In summary, inorganic nitrite, as well as dietary nitrate supplementation, represents a promising therapy for treatment of arterial aging and prevention of age-associated CVD in humans. PMID:24408999

  16. Optical properties of inorganic electroluminescent devices with nanostripe electrodes

    NASA Astrophysics Data System (ADS)

    Nonaka, Toshihiro; Yamamoto, Shin-ichi

    2016-03-01

    In this paper, we report on the luminescence (emission) characteristics of a laminated dispersion-type inorganic electroluminescent (EL) device with a nanostripe electrode made of thin Al film, instead of a conventional indium-tin oxide (ITO) transparent electrode, on the emission side of the device. The transmittance of the Al nanostripe electrode, with 60-nm line-and-space widths, was 45%. We compared an inorganic EL device positioned between two thin films of Al and the inorganic EL device with the Al nanostripe electrode using electric field simulations and actual experiments. We were able to apply the same electric field intensity to the phosphor layer in the conventional structure and to the new structure. Therefore, with an Al nanostripe electrode on one side of the EL device, it is possible to fabricate an ITO-free display.

  17. Inorganic nanoparticle-based contrast agents for molecular imaging

    PubMed Central

    Cho, Eun Chul; Glaus, Charles; Chen, Jingyi; Welch, Michael J.; Xia, Younan

    2010-01-01

    Inorganic nanoparticles including semiconductor quantum dots, iron oxide nanoparticles, and gold nanoparticles have been developed as contrast agents for diagnostics by molecular imaging. Compared to traditional contrast agents, nanoparticles offer several advantages: their optical and magnetic properties can be tailored by engineering the composition, structure, size, and shape; their surfaces can be modified with ligands to target specific biomarkers of disease; the contrast enhancement provided can be equivalent to millions of molecular counterparts; and they can be integrated with a combination of different functions for multi-modal imaging. Here, we review recent advances in the development of contrast agents based on inorganic nanoparticles for molecular imaging, with a touch on contrast enhancement, surface modification, tissue targeting, clearance, and toxicity. As research efforts intensify, contrast agents based on inorganic nanoparticles that are highly sensitive, target-specific, and safe to use are expected to enter clinical applications in the near future. PMID:21074494

  18. Natural Attenuation of Metals from Acid Drainage in Surface Waters: Effects of Organic Matter in the Association of Arsenic to Hydrous Al and Fe Oxyhydroxides and Their Particle Size Distribution

    NASA Astrophysics Data System (ADS)

    Arce, G. J.; Pasten, P.; Coquery, M.; Abarca, M. I.; Montecinos, M.

    2015-12-01

    The presence of toxic metals in watersheds affected by acid drainage (AD) imposes a challenge for sustainable supply of water for cities, agriculture and industry. The formation and settling of metal-rich HFO (hydrous ferric oxides) and HAO (hydrous aluminum oxides) is a relevant mechanism for the attenuation of dissolved metals from AD, particularly for arsenic. Organic matter is known to alter the chemical speciation and key physical properties like particle size distribution (PSD) and settling velocity of HFO and HAO particle suspensions. However, available experimental studies focus either on chemical or physical properties. We used a suite of analytical techniques to probe the effects of organic matter on particle suspensions formed in natural waters and in laboratory model systems. Dissolved organic matter was added at different concentrations (0, 0.1, 0.3, 0.6, 1 and 1.5 mg C/L) to synthetic AD before neutralization with alkaline solutions. PSD and average particle size were measured with laser scattering transmissometry (LISST), while organic matter was characterized by total organic carbon (TOC) and UV-VIS spectrometry. Larger concentrations of organic matter lead to the formation of particle suspensions with larger particle volume and size. When 1.5 mg C/L were added, the total particle volume concentration increased from 0.67 to 23.74 μL/L, while the mean particle size increased from 102 to 176 μm. These results suggests that organic matter influences the fate of metals from AD. Undergoing measurements include total and dissolved metal analyses with total reflection X-ray fluorescence (TXRF) and ICP-OES to confirm increased removal of dissolved arsenic. The results from this research are necessary to understand the processes governing natural attenuation of metal contamination in fluvial systems affected by AD and to serve as the basis for enhanced natural attenuation schemes. The authors acknowledge funding from Fondecyt 1130936.

  19. A Silica/Fly Ash-Based Technology for Controlling Pyrite Oxidation

    SciTech Connect

    V. P. Evangelou

    1997-04-14

    The purpose of our studies during this past six-month period was to evaluate the surface properties of iron-oxide-silicate coatings. The specific objectives were (a) to evaluate the mechanisms and ability of hydrous ferric oxide (HFO) to adsorb silica (Si); (b) to evaluate the effects of Si on the bulk and surface properties of HFO; and (c) to evaluate the effect of Si on heavy-metal adsorption properties by iron-oxides.

  20. Shock compression of silica gel as the analog experiments of hydrous comet and meteorite

    NASA Astrophysics Data System (ADS)

    Arasuna, Akane; Okuno, Masayuki; Mizukami, Tomoyuki; Chen, Liliang; Mashimo, Tsutomu; Arai, Shoji; Okudera, Hiroki

    2013-04-01

    The studies for structural changes of hydrous silica materials by shock compression are important to obtain the information for compression behaviors of comet and meteorite made of silicate material, ice and hydroxyl on the impact event. In this study, TEOS-derived synthetic silica gels for the analog material of hydrous amorphous silica minerals were compressed under shock pressures of 11, 13, 17, 21, 27, and 31 GPa using a single-stage propellant gun. All recovered samples have been investigated by XRD measurements, Raman and IR spectroscopies, in order to elucidate the shock compression behavior of silica gel. Pressure variation of first sharp diffraction peak (FSDP) positions of samples was estimated from measured XRD patterns. FSDP position of as-prepared sample was smaller than silica glass. It indicates that medium range structure of silica gel, i.e. ring structure of SiO4 tetrahedra, is smaller than that of silica glass. FSDP positions showed negative shift with increasing pressure and approached that of silica glass at 31 GPa. It suggests that medium range structure of silica gel approached to silica glass by shock compression. Raman spectrum of as-prepared sample showed an intense D1 band at 480 cm-1 and a broad band at around 450 cm-1. The former is attributed to the oxygen-breathing mode of the four-membered ring of SiO4 tetrahedra and the latter to the symmetrical Si-O-Si stretching mode. The presence of strong D1 band of as-prepared sample indicates that the sample might contain considerable amount of four-membered rings in the structure. Shocked sample showed that the broad band around 450 cm-1 became prominent above 21 GPa, whereas D1 band became much less intense. These indicate that medium range structure of shocked sample above 21 GPa approached to that of silica glass. Furthermore, IR spectrum of shocked silica gel at 21 GPa indicates that the center part of sample showed development of vitrification as compared with the extremity part of the

  1. Protein-inorganic hybrid nanoflowers

    NASA Astrophysics Data System (ADS)

    Ge, Jun; Lei, Jiandu; Zare, Richard N.

    2012-07-01

    Flower-shaped inorganic nanocrystals have been used for applications in catalysis and analytical science, but so far there have been no reports of `nanoflowers' made of organic components. Here, we report a method for creating hybrid organic-inorganic nanoflowers using copper (II) ions as the inorganic component and various proteins as the organic component. The protein molecules form complexes with the copper ions, and these complexes become nucleation sites for primary crystals of copper phosphate. Interaction between the protein and copper ions then leads to the growth of micrometre-sized particles that have nanoscale features and that are shaped like flower petals. When an enzyme is used as the protein component of the hybrid nanoflower, it exhibits enhanced enzymatic activity and stability compared with the free enzyme. This is attributed to the high surface area and confinement of the enzymes in the nanoflowers.

  2. Diffusion of dissolved CO sub 2 and Cl in hydrous silicic to intermediate magmas

    SciTech Connect

    Watson, E.B. )

    1991-07-01

    The bulk diffusivity of dissolved CO{sub 2} in obsidian and dacite melts containing 0-11 wt% dissolved water at 800-1,100C and 1 GPa was characterized using a {sup 14}C radiotracer technique. Five values were also obtained for Cl in melts containing 8% H{sub 2}O. Carbon dioxide diffusivity (D{sub CO{sub 2}}) in nominally dry molten obsidian is similar to previously reported values for a simple melt in the Na{sub 2}O-Al{sub 2}O{sub 3}-SiO{sub 2} system and for dry basalt, indicating little effect of melt composition on bulk CO{sub 2} diffusion. Three D{sub CO{sub 2}} values for hydrous dacite melt are consistent with this lack of a melt composition effect. Dissolved water, however, causes an increase of D{sub CO{sub 2}} in molten obsidian by about an order of magnitude for each 5% of added water. The activation energy of {approximately}18 kcal/mol is lower by a factor of {approximately}3 than that for diffusion in dry basalt. In comparison with existing data for diffusion of water in silicic melts at their typical liquidus temperatures, D{sub CO{sub 2}} is generally lower unless the melt contains more than about 6% dissolved H{sub 2}O, in which case D{sub CO{sub 2}} {approximately} D{sub H{sub 2}0}. The few data obtained from chlorine diffusion reveal the D{sub Cl} is lower by a factor of 5-10 than D{sub CO{sub 2}} in the same melt. The overall systematics of the new data on dissolved volatile diffusion indicate that diffusional fractionation effects are likely to be most significant in silicic to intermediate magmas having water contents in the 0-4% range.

  3. Sound velocities of hydrous ringwoodite to 16 GPa and 673 K

    SciTech Connect

    Mao, Zhu; Lin, Jung-Fu; Jacobsen, Steven D.; Duffy, Thomas S.; Chang, Yun-Yuan; Smyth, Joseph R.; Frost, Daniel J.; Hauri, Erik H.; Prakapenka, Vitali B.

    2012-05-10

    To understand the effect of hydration on the sound velocities of major mantle minerals and to constrain the mantle's H{sub 2}O budget, we have measured the single-crystal elastic moduli of hydrous ringwoodite, (Mg{sub 1.633}Fe{sub 0.231}{sup 2+}Fe{sub 0.026}{sup 3+})Si{sub 1.00}H{sub 0.179}O{sub 4} with 1.1 wt.% H{sub 2}O using Brillouin scattering combined with X-ray diffraction in an externally-heated diamond anvil cell up to 16 GPa and 673 K. Up to 12 GPa at 300 K, the presence of 1.1 wt.% H{sub 2}O lowers the elastic moduli of ringwoodite by 5-9%, but does not affect the pressure derivatives of the elastic moduli compared to anhydrous ringwoodite. The reduction caused by hydration is significantly enhanced when temperatures are elevated at high pressures. At 12 GPa, increasing temperature by {Delta}T = 100 K leads to a 1.3-2.4% reduction in the elastic moduli (C{sub 11}, C{sub 12}, and C{sub 14}). Comparing our results with seismic observations, we have evaluated the potential H{sub 2}O content in the lower part of the transition zone. Our results indicate that the observed seismic velocity anomalies and related depth depression of the 660-km discontinuity could be attributed to thermal variations together with the presence of {approx} 0.1 wt.% H{sub 2}O.

  4. Plagioclase nucleation and growth kinetics in a hydrous basaltic melt by decompression experiments

    NASA Astrophysics Data System (ADS)

    Arzilli, Fabio; Agostini, C.; Landi, P.; Fortunati, A.; Mancini, L.; Carroll, M. R.

    2015-12-01

    Isothermal single-step decompression experiments (at temperature of 1075 °C and pressure between 5 and 50 MPa) were used to study the crystallization kinetics of plagioclase in hydrous high-K basaltic melts as a function of pressure, effective undercooling (Δ T eff) and time. Single-step decompression causes water exsolution and a consequent increase in the plagioclase liquidus, thus imposing an effective undercooling (∆ T eff), accompanied by increased melt viscosity. Here, we show that the decompression process acts directly on viscosity and thermodynamic energy barriers (such as interfacial-free energy), controlling the nucleation process and favoring the formation of homogeneous nuclei also at high pressure (low effective undercoolings). In fact, this study shows that similar crystal number densities ( N a) can be obtained both at low and high pressure (between 5 and 50 MPa), whereas crystal growth processes are favored at low pressures (5-10 MPa). The main evidence of this study is that the crystallization of plagioclase in decompressed high-K basalts is more rapid than that in rhyolitic melts on similar timescales. The onset of the crystallization process during experiments was characterized by an initial nucleation event within the first hour of the experiment, which produced the largest amount of plagioclase. This nucleation event, at short experimental duration, can produce a dramatic change in crystal number density ( N a) and crystal fraction ( ϕ), triggering a significant textural evolution in only 1 h. In natural systems, this may affect the magma rheology and eruptive dynamics on very short time scales.

  5. Inorganic nanotube nanofluidics

    NASA Astrophysics Data System (ADS)

    Fan, Rong

    The ability to manipulate charge carriers (electrons and holes) in metal-oxide semiconductor field effect transistors (MOSFETs) has revolutionized how information is processed and stored, and created the modern digital age. Introducing direct field effect modulation in fluidic systems would enable the manipulation of ionic and molecular species at a similar level and even logic operation. Due to strong Debye screening in aqueous solutions, field effect manipulation of ion transport arises only in systems whose dimensions are comparable to the critical Debye Length, i.e. in nanofluidic systems. Nanofluidics has already been explored in various cases, e.g. biological channel proteins and artificial solid-state nanopores. All these two terminal systems usually transport the ions the same way as passive electron conduction in a resistor. My work is aimed at developing nanotube nanofluidic units with a third terminal that can electrically turn on/off and control ion and biomolecule transport. Moreover, the systematic study on "doping" and transient phenomena can provide rich information to assess the electrokinetics theory and fluidic physics in nanoscale. Silica nanotubes were synthesized by oxidation/etching approach using vertical silicon nanowires as templates. A single nanotube was integrated into a metal-oxide-solution field effect transistor (MOSolFET) by interfacing with two microfluidic channels and a metallic gate electrode. Concentration dependence of ionic conductance through single nanotubes revealed the emergence of unipolar environment at low ionic strength regime. In this case, ionic conductance is only associated with majority ions and governed by surface potentials and charge densities. By applying a gate voltage, the ionic conductance can be quickly modulated. The gate voltages alter the surface potential of the silica nanotubes via capacitive coupling through the nanotube wall and the electrical double layer. In a negatively charged silica nanotube

  6. Principles of Inorganic Materials Design

    NASA Astrophysics Data System (ADS)

    Lalena, John N.; Cleary, David

    2005-04-01

    A unique interdisciplinary approach to inorganic materials design Textbooks intended for the training of chemists in the inorganic materials field often omit many relevant topics. With its interdisciplinary approach, this book fills that gap by presenting concepts from chemistry, physics, materials science, metallurgy, and ceramics in a unified treatment targeted towards the chemistry audience. Semiconductors, metal alloys and intermetallics, as well as ceramic substances are covered. Accordingly, the book should also be useful to students and working professionals in a variety of other disciplines. This book discusses a number of topics that are pertinent to the design of new inorganic materials but are typically not covered in standard solid-state chemistry books. The authors start with an introduction to structure at the mesoscopic level and progress to smaller-length scales. Next, detailed consideration is given to both phenomenological and atomistic-level descriptions of transport properties, the metal-nonmetal transition, magnetic and dielectric properties, optical properties, and mechanical properties. Finally, the authors present introductions to phase equilibria, synthesis, and nanomaterials. Other features include: Worked examples demonstrating concepts unfamiliar to the chemist Extensive references to related literature, leading readers to more in-depth coverage of particular topics Biographies introducing the reader to great contributors to the field of inorganic materials science in the twentieth century With their interdisciplinary approach, the authors have set the groundwork for communication and understanding among professionals in varied disciplines who are involved with inorganic materials engineering. Armed with this publication, students and researchers in inorganic and physical chemistry, physics, materials science, and engineering will be better equipped to face today's complex design challenges. This textbook is appropriate for senior

  7. Inorganic nanoparticles in porous coordination polymers.

    PubMed

    Kim, Cho Rong; Uemura, Takashi; Kitagawa, Susumu

    2016-07-21

    Porous coordination polymers (PCPs) have been recently highlighted because of their high synthetic designability in structure and functions. Because of their ordered nanoporous structures with a large surface area and tunable pore surface functionality, PCPs have emerged as a significant class of nanoporous materials with potential applications in gas storage, separation, catalysis, and chemical sensing. Recent research has shown the utility of PCPs as host materials for the confinement of nanoparticles of inorganic polymers (IPs), such as metals, metal oxides, and metal chalcogenides. The fabrication of IP nanoparticles in PCPs (PCP⊃IP) has been studied for manifesting specific nanosized-dependent properties and host-guest synergistic functions. In this review, we describe the recent progress in the accommodation of IPs in the nanochannels of PCPs and the remarkable functions of the composite materials. PMID:27051891

  8. Applications of inorganic nanoparticles as therapeutic agents

    NASA Astrophysics Data System (ADS)

    Kim, Taeho; Hyeon, Taeghwan

    2014-01-01

    During the last decade, various functional nanostructured materials with interesting optical, magnetic, mechanical and chemical properties have been extensively applied to biomedical areas including imaging, diagnosis and therapy. In therapeutics, most research has focused on the application of nanoparticles as potential delivery vehicles for drugs and genes, because nanoparticles in the size range of 2-100 nm can interact with biological systems at the molecular level, and allow targeted delivery and passage through biological barriers. Recent investigations have even revealed that several kinds of nanomaterials are intrinsically therapeutic. Not only can they passively interact with cells, but they can also actively mediate molecular processes to regulate cell functions. This can be seen in the treatment of cancer via anti-angiogenic mechanisms as well as the treatment of neurodegenerative diseases by effectively controlling oxidative stress. This review will present recent applications of inorganic nanoparticles as therapeutic agents in the treatment of disease.

  9. Toxicological review of inorganic phosphates.

    PubMed

    Weiner, M L; Salminen, W F; Larson, P R; Barter, R A; Kranetz, J L; Simon, G S

    2001-08-01

    Inorganic phosphate salts are widely used as food ingredients and in a variety of commercial applications. The United States Food and Drug Administration (FDA) considers inorganic phosphates "Generally Recognized As Safe" (GRAS) (FDA, 1973a, 1979) [FDA: Food and Drug Administration 1973a. GRAS (Generally Recognized as Safe) food ingredients-phosphates. NTIS PB-221-224, FDA, Food and Drug Administration, 1979. Phosphates; Proposed Affirmation of and Deletion From GRAS Status as Direct and Human Food Ingredients. Federal Register 44 (244). 74845-74857, 18 December (1979)] and the European Union (EU) allows inorganic phosphates to be added directly to food (EU Directive 95/2/EC as amended by 98/72/EC). In this review, data on the acute, subchronic and chronic toxicity, genotoxicity, teratogenicity and reproductive toxicity from the published literature and from unpublished studies by the manufacturers are reviewed. Based on the toxicity data and similar chemistry, the inorganic phosphates can be separated into four major classes, consisting of monovalent salts, divalent salts, ammonium salts and aluminum salts. The proposed classification scheme supports the use of toxicity data from one compound to assess the toxicity of another compound in the same class. However, in the case of eye and skin irritation, the proposed classification scheme cannot be used because a wide range of responses exists within each class. Therefore, the eye and skin hazards associated with an individual inorganic phosphate should be assessed on a chemical-by-chemical basis. A large amount of toxicity data exists for all four classes of inorganic phosphates. The large and comprehensive database allows an accurate assessment of the toxicity of each class of inorganic phosphate. Overall, all four classes of inorganic phosphates exhibit low oral, inhalation and dermal toxicities. Based on these data, humans are unlikely to experience adverse effects when the daily phosphorus consumption remains

  10. Distribution of inorganic species in two Antarctic cryptoendolithic microbial communities

    NASA Technical Reports Server (NTRS)

    Johnston, C. G.; Vestal, J. R.; Friedmann, E. I. (Principal Investigator)

    1989-01-01

    Chemical differences were noted between two Antarctic cryptoendolithic (hidden within rock) microenvironments colonized by different microbial communities. Microenvironments dominated by cyanobacteria (BPC) had a higher pH (pH 7-8) than those dominated by lichen (LTL) (pH 4.5-5.5). In order to understand the interactions between the microbiota and the inorganic environment, the inorganic environment was characterized. Water-soluble, carbonate-bound, metal-oxide, organically bound, and residual inorganic species were sequentially extracted from rock samples by chemical means. Each fraction was then quantified using inductively coupled plasma atomic emission spectrometry. BPC contained much more water-soluble and carbonate-bound Ca and Mg than LTL. Metal-oxide species of Al, Fe, and Mn were more abundant in LTL than BPC. Metal oxides appeared to be mobilized (in the order Mn > Fe > Al) from the LTL lichen zone but remained immobile in BPC sandstone. The distribution of K and P bound to metal oxide reflected the distribution of iron oxide in LTL, an indication of the importance of iron in controlling the availability of nutrients in this ecosystem. Metal oxides in turn were likely controlled or influenced by organic matter associated with the lichen community. Despite overall depletion of Fe, Al, and K in the lichen zone, SEM X-ray analysis showed that they were enriched in fungal hyphae. Water-soluble P was present despite the presence of metal oxides, which sequester phosphate. This has biological relevance since P is an essential nutrient.

  11. Soft templating strategies for the synthesis of mesoporous materials: inorganic, organic-inorganic hybrid and purely organic solids.

    PubMed

    Pal, Nabanita; Bhaumik, Asim

    2013-03-01

    With the discovery of MCM-41 by Mobil researchers in 1992 the journey of the research on mesoporous materials started and in the 21st century this area of scientific investigation have extended into numerous branches, many of which contribute significantly in emerging areas like catalysis, energy, environment and biomedical research. As a consequence thousands of publications came out in large varieties of national and international journals. In this review, we have tried to summarize the published works on various synthetic pathways and formation mechanisms of different mesoporous materials viz. inorganic, organic-inorganic hybrid and purely organic solids via soft templating pathways. Generation of nanoscale porosity in a solid material usually requires participation of organic template (more specifically surfactants and their supramolecular assemblies) called structure-directing agent (SDA) in the bottom-up chemical reaction process. Different techniques employed for the syntheses of inorganic mesoporous solids, like silicas, metal doped silicas, transition and non-transition metal oxides, mixed oxides, metallophosphates, organic-inorganic hybrids as well as purely organic mesoporous materials like carbons, polymers etc. using surfactants are depicted schematically and elaborately in this paper. Moreover, some of the frontline applications of these mesoporous solids, which are directly related to their functionality, composition and surface properties are discussed at the appropriate places.

  12. Evaluation of the microbial growth response to inorganic nanoparticles

    PubMed Central

    Williams, Darryl N; Ehrman, Sheryl H; Pulliam Holoman, Tracey R

    2006-01-01

    In order to enhance the utilization of inorganic nanoparticles in biological systems, it is important to develop a fundamental understanding of the influence they have on cellular health and function. Experiments were conducted to test silica, silica/iron oxide, and gold nanoparticles for their effects on the growth and activity of Escherichia coli (E. coli). Transmission electron microscopy (TEM) and dynamic light scattering (DLS) were used to characterize the morphology and quantify size distribution of the nanoparticles, respectively. TEM was also used to verify the interactions between composite iron oxide nanoparticles and E. coli. The results from DLS indicated that the inorganic nanoparticles formed small aggregates in the growth media. Growth studies measured the influence of the nanoparticles on cell proliferation at various concentrations, showing that the growth of E. coli in media containing the nanoparticles indicated no overt signs of toxicity. PMID:16507102

  13. Evaluating Re-Os systematics in organic-rich sedimentary rocks in response to petroleum generation using hydrous pyrolysis experiments

    USGS Publications Warehouse

    Rooney, A.D.; Selby, D.; Lewan, M.D.; Lillis, P.G.; Houzay, J.-P.

    2012-01-01

    Successful application of the 187Re–187Os geochronometer has enabled the determination of accurate and precise depositional ages for organic-rich sedimentary rocks (ORS) as well as establishing timing constraints of petroleum generation. However, we do not fully understand the systematics and transfer behaviour of Re and Os between ORS and petroleum products (e.g., bitumen and oil). To more fully understand the behaviour of Re–Os systematics in both source rocks and petroleum products we apply hydrous pyrolysis to two immature hydrocarbon source rocks: the Permian Phosphoria Formation (TOC = 17.4%; Type II-S kerogen) and the Jurassic Staffin Formation (TOC = 2.5%; Type III kerogen). The laboratory-based hydrous pyrolysis experiments were carried out for 72 h at 250, 300, 325 and 350 °C. These experiments provided us with whole rock, extracted rock and bitumen and in some cases expelled oil and asphaltene for evaluation of Re–Os isotopic and elemental abundance. The data from these experiments demonstrate that the majority (>95%) of Re and Os are housed within extracted rock and that thermal maturation does not result in significant transfer of Re or Os from the extracted rock into organic phases. Based on existing thermodynamic data our findings suggest that organic chelating sites have a greater affinity for the quadravalent states of Re and Os than sulphides. Across the temperature range of the hydrous pyrolysis experiments both whole rock and extracted rock 187Re/188Os ratios show small variations (3.3% and 4.7%, for Staffin, respectively and 6.3% and 4.9% for Phosphoria, respectively). Similarly, the 187Os/188Os ratios show only minor variations for the Staffin and Phosphoria whole rock and extracted rock samples (0.6% and 1.4% and 1.3% and 2.2%). These isotopic data strongly suggest that crude oil generation through hydrous pyrolysis experiments does not disturb the Re–Os systematics in ORS as supported by various studies on natural systems. The

  14. Strongly coupled inorganic-nano-carbon hybrid materials for energy storage.

    PubMed

    Wang, Hailiang; Dai, Hongjie

    2013-04-01

    The global shift of energy production from fossil fuels to renewable energy sources requires more efficient and reliable electrochemical energy storage devices. In particular, the development of electric or hydrogen powered vehicles calls for much-higher-performance batteries, supercapacitors and fuel cells than are currently available. In this review, we present an approach to synthesize electrochemical energy storage materials to form strongly coupled hybrids (SC-hybrids) of inorganic nanomaterials and novel graphitic nano-carbon materials such as carbon nanotubes and graphene, through nucleation and growth of nanoparticles at the functional groups of oxidized graphitic nano-carbon. We show that the inorganic-nano-carbon hybrid materials represent a new approach to synthesize electrode materials with higher electrochemical performance than traditional counterparts made by simple physical mixtures of electrochemically active inorganic particles and conducting carbon materials. The inorganic-nano-carbon hybrid materials are novel due to possible chemical bonding between inorganic nanoparticles and oxidized carbon, affording enhanced charge transport and increased rate capability of electrochemical materials without sacrificing specific capacity. Nano-carbon with various degrees of oxidation provides a novel substrate for nanoparticle nucleation and growth. The interactions between inorganic precursors and oxidized-carbon substrates provide a degree of control over the morphology, size and structure of the resulting inorganic nanoparticles. This paper reviews the recent development of inorganic-nano-carbon hybrid materials for electrochemical energy storage and conversion, including the preparation and functionalization of graphene sheets and carbon nanotubes to impart oxygen containing groups and defects, and methods of synthesis of nanoparticles of various morphologies on oxidized graphene and carbon nanotubes. We then review the applications of the SC

  15. Diamondoid hydrocarbons as a molecular proxy for thermal maturity and oil cracking: Geochemical models from hydrous pyrolysis

    USGS Publications Warehouse

    Wei, Z.; Moldowan, J.M.; Zhang, S.; Hill, R.; Jarvie, D.M.; Wang, Hongfang; Song, F.; Fago, F.

    2007-01-01

    A series of isothermal hydrous pyrolysis experiments was performed on immature sedimentary rocks and peats of different lithology and organic source input to explore the generation of diamondoids during the thermal maturation of sediments. Oil generation curves indicate that peak oil yields occur between 340 and 360 ??C, followed by intense oil cracking in different samples. The biomarker maturity parameters appear to be insensitive to thermal maturation as most of the isomerization ratios of molecular biomarkers in the pyrolysates have reached their equilibrium values. Diamondoids are absent from immature peat extracts, but exist in immature sedimentary rocks in various amounts. This implies that they are not products of biosynthesis and that they may be generated during diagenesis, not just catagenesis and cracking. Most importantly, the concentrations of diamondoids are observed to increase with thermal stress, suggesting that they can be used as a molecular proxy for thermal maturity of source rocks and crude oils. Their abundance is most sensitive to thermal exposure above temperatures of 360-370 ??C (R0 = 1.3-1.5%) for the studied samples, which corresponds to the onset of intense cracking of other less stable components. Below these temperatures, diamondoids increase gradually due to competing processes of generation and dilution. Calibrations were developed between their concentrations and measured vitrinite reflectance through hydrous pyrolysis maturation of different types of rocks and peats. The geochemical models obtained from these methods may provide an alterative approach for determining thermal maturity of source rocks and crude oils, particularly in mature to highly mature Paleozoic carbonates. In addition, the extent of oil cracking was quantified using the concentrations of diamondoids in hydrous pyrolysates of rocks and peats, verifying that these hydrocarbons are valuable indicators of oil cracking in nature. ?? 2006 Elsevier Ltd. All rights

  16. Differentiation of pre-existing trapped methane from thermogenic methane in an igneous-intruded coal by hydrous pyrolysis

    USGS Publications Warehouse

    Dias, Robert F.; Lewan, Michael D.; Birdwell, Justin E.; Kotarba, Maciej J.

    2014-01-01

    So as to better understand how the gas generation potential of coal changes with increasing rank, same-seam samples of bituminous coal from the Illinois Basin that were naturally matured to varying degrees by the intrusion of an igneous dike were subjected to hydrous pyrolysis (HP) conditions of 360 °C for 72 h. The accumulated methane in the reactor headspace was analyzed for δ13C and δ2H, and mol percent composition. Maximum methane production (9.7 mg/g TOC) occurred in the most immature samples (0.5 %Ro), waning to minimal methane values at 2.44 %Ro (0.67 mg/g TOC), and rebounding to 3.6 mg/g TOC methane in the most mature sample (6.76 %Ro). Methane from coal with the highest initial thermal maturity (6.76 %Ro) shows no isotopic dependence on the reactor water and has a microbial δ13C value of −61‰. However, methane from coal of minimal initial thermal maturity (0.5 %Ro) shows hydrogen isotopic dependence on the reaction water and has a δ13C value of −37‰. The gas released from coals under hydrous pyrolysis conditions represents a quantifiable mixture of ancient (270 Ma) methane (likely microbial) that was generated in situ and trapped within the rock during the rapid heating by the dike, and modern (laboratory) thermogenic methane that was generated from the indigenous organic matter due to thermal maturation induced by hydrous pyrolysis conditions. These findings provide an analytical framework for better assessment of natural gas sources and for differentiating generated gas from pre-existing trapped gas in coals of various ranks.

  17. Inorganic Fullerenes, Onions, and Tubes

    ERIC Educational Resources Information Center

    York, Andrew P. E.

    2004-01-01

    Buckminsterfullerene, which is in the shape of a soccer-ball was first discovered in 1985, has many applications as a good lubricant, or as a new superconductor. The synthesis of these inorganic fullerenes involves a great deal of interdisciplinary research between physicists, material scientists, engineers and chemists from various fields.

  18. Inorganic Reaction Mechanisms. Part I

    ERIC Educational Resources Information Center

    Cooke, D. O.

    1976-01-01

    Provides a collection of data on the mechanistic aspects of inorganic chemical reactions. Wherever possible includes procedures for classroom demonstration or student project work. The material covered includes gas phase reactions, reactions in solution, mechanisms of electron transfer, the reaction between iron III and iodine, and hydrolysis. (GS)

  19. Infrared Spectrometry of Inorganic Salts

    ERIC Educational Resources Information Center

    Ackermann, Martin N.

    1970-01-01

    Describes a general chemistry experiment which uses infrared spectroscopy to analyze inorganic ions and thereby serves to introduce an important instrumental method of analysis. Presents a table of eight anions and the ammonium ion with the frequencies of their normal modes, as well as the spectra of three sulfate salts. (RR)

  20. Organic/inorganic nanocomposites, methods of making, and uses as a permeable reactive barrier

    DOEpatents

    Harrup, Mason K.; Stewart, Frederick F.

    2007-05-15

    Nanocomposite materials having a composition including an inorganic constituent, a preformed organic polymer constituent, and a metal ion sequestration constituent are disclosed. The nanocomposites are characterized by being single phase, substantially homogeneous materials wherein the preformed polymer constituent and the inorganic constituent form an interpenetrating network with each other. The inorganic constituent may be an inorganic oxide, such as silicon dioxide, formed by the in situ catalyzed condensation of an inorganic precursor in the presence of the solvated polymer and metal ion sequestration constituent. The polymer constituent may be any hydrophilic polymer capable of forming a type I nanocomposite such as, polyacrylonitrile (PAN), polyethyleneoxide (PEO), polyethylene glycol (PEG), polyvinyl acetate (PVAc), polyvinyl alcohol (PVA), and combinations thereof. Nanocomposite materials of the present invention may be used as permeable reactive barriers (PRBs) to remediate contaminated groundwater. Methods for making nanocomposite materials, PRB systems, and methods of treating groundwater are also disclosed.

  1. LETTER TO THE EDITOR: Hydrous species in ceramics for the encapsulation of nuclear waste: OH in zircon

    NASA Astrophysics Data System (ADS)

    Salje, Ekhard K. H.; Zhang, Ming

    2006-06-01

    The partition of hydrous species in radiation-damaged zircon was investigated using infrared spectra from a large range of samples with different degrees of radiation damage and a variety of geological conditions. The results of the present study showed uniformly a partition coefficient of K = 0.3. This indicates that OH is enriched in the damaged crystalline phase and not in the amorphous phase. The uniformity of the results for all samples indicates equilibrium rather than a frozen-in kinetic behaviour. It is possible that the enrichment of OH in the damaged crystalline phase of zircon indicates a catalytic effect of hydrogen during recrystallization events.

  2. Synthesis and electron microscopy of inorganic and hybrid organic-inorganic mesoporous and macroporous materials

    NASA Astrophysics Data System (ADS)

    Blanford, Christopher Francis

    This work describes the creation and analysis of ordered porous inorganic and organic-inorganic hybrid materials with an emphasis on the qualitative and quantitative characterization by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Two major systems were studied: MCM-41-type mesoporous molecular sieves and three-dimensionally ordered macroporous (3DOM) materials. The microanalysis of mesoporous samples is discussed first. Samples of unmodified siliceous MCM-41, MCM-41 with grafted titanium dioxide species, and MCM-41 with incorporated 3-mercaptopropyl groups were examined in the TEM at three accelerating voltages. The beam stability of all the samples increased with increasing accelerating voltage. The particles were significantly more resistant to beam damage with the surfactant template in place, when the samples were synthesized above room temperature, and when the silicate precursor was hydrolyzed in acid. The samples with organic and inorganic groups were more stable than siliceous analogs. The discussion of 3DOM materials begins with their synthesis and characterization: 3DOM materials were created from colloidal crystals of uniform, sub-micrometer diameter polystyrene and poly(methyl methacrylate) spheres. Metal alkoxides, solutions of metal salts, and mixed salt-alkoxide precursors were employed to create 3DOM metal oxides, silicates with incorporated organic groups and polyoxometalate clusters, metals, and metal alloys. SEM and TEM were used extensively to characterize the morphology, crystallinity, grain size, and phase of the 3DOM products. The formation of 3DOM nickel oxide was studied by heating a nickel oxalate-colloidal crystal composite in an environmental SEM. The growth of the grains in 3DOM cobalt metal and 3DOM iron oxide were observed by high-temperature TEM. The arrangement of the pores in 3DOM materials was studied by analyzing diffractograms of TEM images of single particles tilted into different orientations

  3. Creep of porous rocks and measurements of elastic wave velocities under different hydrous conditions

    NASA Astrophysics Data System (ADS)

    Eslami, J.; Grgic, D.; Hoxha, D.

    2009-04-01

    of strains on a same sample, under uniaxial compression. Different hydrous conditions (saturated or partially saturated) are tested in all creep tests. In this paper, we focus on the time-dependent behavior and short-term mechanical behavior of iron ore and limestone in saturated and partially saturated domains. The main outcomes of these experiments are: (i) identification of the apparent dynamic stiffness tensor from elastic wave velocity measurements; (ii) assessment of velocity anisotropy, and its evolution under uniaxial loading. This last step allows for the quantification of the intrinsic and stress-induced anisotropies, leading eventually to an estimation of the microcracks density and distribution evolutions in the rock sample under loading.

  4. The Amphibole-Bearing Chondrite Meteorite LAP04840: Metamorphism and `Tectonics' in a Hydrous Asteroid

    NASA Astrophysics Data System (ADS)

    Treiman, A. H.; McCanta, M. C.; Essene, E. J.

    2006-12-01

    C (Ghosh et al., 2006). This is the puzzle of LAP how can it be both hydrous and have reached high temperature?

  5. Evaluating transition-metal catalysis in gas generation from the Permian Kupferschiefer by hydrous pyrolysis

    USGS Publications Warehouse

    Lewan, M.D.; Kotarba, M.J.; Wieclaw, D.; Piestrzynski, A.

    2008-01-01

    Transition metals in source rocks have been advocated as catalysts in determining extent, composition, and timing of natural gas generation (Mango, F. D. (1996) Transition metal catalysis in the generation of natural gas. Org. Geochem.24, 977–984). This controversial hypothesis may have important implications concerning gas generation in unconventional shale-gas accumulations. Although experiments have been conducted to test the metal-catalysis hypothesis, their approach and results remain equivocal in evaluating natural assemblages of transition metals and organic matter in shale. The Permian Kupferschiefer of Poland offers an excellent opportunity to test the hypothesis with immature to marginally mature shale rich in both transition metals and organic matter. Twelve subsurface samples containing similar Type-II kerogen with different amounts and types of transition metals were subjected to hydrous pyrolysis at 330° and 355 °C for 72 h. The gases generated in these experiments were quantitatively collected and analyzed for molecular composition and stable isotopes. Expelled immiscible oils, reacted waters, and spent rock were also quantitatively collected. The results show that transition metals have no effect on methane yields or enrichment. δ13C values of generated methane, ethane, propane and butanes show no systematic changes with increasing transition metals. The potential for transition metals to enhance gas generation and oil cracking was examined by looking at the ratio of the generated hydrocarbon gases to generated expelled immiscible oil (i.e., GOR), which showed no systematic change with increasing transition metals. Assuming maximum yields at 355 °C for 72 h and first-order reaction rates, pseudo-rate constants for methane generation at 330 °C were calculated. These rate constants showed no increase with increasing transition metals. The lack of a significant catalytic effect of transition metals on the extent, composition, and timing of

  6. Structure and properties of ITQ-8: a hydrous layer silicate with microporous silicate layers.

    PubMed

    Marler, Bernd; Müller, Melanie; Gies, Hermann

    2016-06-21

    ITQ-8 is a new hydrous layer silicate (HLS) with a chemical composition of [C4H8(C7H13N)2]8 [Si64O128(OH)16]·48H2O per unit cell. The synthesis of ITQ-8 was first described in 2002 by Díaz-Cabañas et al., the structure of this material, however, remained unsolved at that time. Physico-chemical characterization using solid-state NMR spectroscopy, SEM, TG-DTA, and FTIR spectroscopy confirmed that ITQ-8 is a layer silicate. The XRD powder pattern was indexed in the monoclinic system with lattice parameters of a0 = 35.5168(5) Å, b0 = 13.3989(2) Å, c0 = 16.0351(2) Å, β = 106.74(2)°. The crystal structure was solved by simulated annealing. Rietveld refinement of the structure in space group C2/c converged to residual values of RBragg = 0.023, RF = 0.022 and chi(2) = 2.3 confirming the structure model. The structure of ITQ-8 contains silicate layers with a topology that resembles a (11-1) section of the framework of zeolite levyne. So far, this layer topology is unique among layer silicates. The layer can be regarded as made up of 4-, 6-, double-six and 8-rings which are interconnected to form cup-like "half-cages". Unlike other HLSs, which possess impermeable silicate layers, ITQ-8 contains 8-rings pores with a free diameter of 3.5 Å × 3.4 Å and can be regarded as a "small-pore layer silicate". In the crystal structure, the organic cations, 1,4-diquiniclidiniumbutane, used as structure directing agents during synthesis are intercalated between the silicate layers. Clusters (bands) of water molecules which are hydrogen bonded to each other and to the terminal Si-OH/Si-O(-) groups are located between the organic cations and interconnect the silicate layers. ITQ-8 is a very interesting material as precursor for the synthesis of microporous framework silicates by topotactic condensation or interlayer expansion reactions leading to 3D micro-pore systems which may be useful in applications as e.g. catalysts, catalyst supports and adsorbents of for separation. PMID

  7. Evaluating transition-metal catalysis in gas generation from the Permian Kupferschiefer by hydrous pyrolysis

    NASA Astrophysics Data System (ADS)

    Lewan, M. D.; Kotarba, M. J.; Więcław, D.; Piestrzyński, A.

    2008-08-01

    Transition metals in source rocks have been advocated as catalysts in determining extent, composition, and timing of natural gas generation (Mango, F. D. (1996) Transition metal catalysis in the generation of natural gas. Org. Geochem.24, 977-984). This controversial hypothesis may have important implications concerning gas generation in unconventional shale-gas accumulations. Although experiments have been conducted to test the metal-catalysis hypothesis, their approach and results remain equivocal in evaluating natural assemblages of transition metals and organic matter in shale. The Permian Kupferschiefer of Poland offers an excellent opportunity to test the hypothesis with immature to marginally mature shale rich in both transition metals and organic matter. Twelve subsurface samples containing similar Type-II kerogen with different amounts and types of transition metals were subjected to hydrous pyrolysis at 330° and 355 °C for 72 h. The gases generated in these experiments were quantitatively collected and analyzed for molecular composition and stable isotopes. Expelled immiscible oils, reacted waters, and spent rock were also quantitatively collected. The results show that transition metals have no effect on methane yields or enrichment. δ 13C values of generated methane, ethane, propane and butanes show no systematic changes with increasing transition metals. The potential for transition metals to enhance gas generation and oil cracking was examined by looking at the ratio of the generated hydrocarbon gases to generated expelled immiscible oil (i.e., GOR), which showed no systematic change with increasing transition metals. Assuming maximum yields at 355 °C for 72 h and first-order reaction rates, pseudo-rate constants for methane generation at 330 °C were calculated. These rate constants showed no increase with increasing transition metals. The lack of a significant catalytic effect of transition metals on the extent, composition, and timing of

  8. Maturation of Green River Shale Kerogen with Hydrous Pyrolysis: Characterization of Geochemical Biomarkers and Carbon Isotopes

    NASA Astrophysics Data System (ADS)

    Fu, Q.; Darnell, M.; Bissada, K. K.

    2014-12-01

    To fully understand controlling factors of organic compound generation during oil shale maturation, and systematically assess associated carbon isotope values, a series of hydrous pyrolysis experiments are performed. Kerogen was isolated from Green River shale by a set of acid treatment. Experiments are conducted at 350 °C and 300 bars of total pressure with running time of 24, 48 and 72 hours, respectively. In each experiment, the reactor contains 1.5 grams of kerogen and 30 grams of deionized water. After experiments, gaseous products are removed under cryogenic conditions for chemical and carbon isotope analyses (GC-IRMS). The bitumen product is retrieved and separated into saturated hydrocarbons, aromatics, resins, and asphaltenes (SARA) by HPLC before subsequent analyses (GC, GC-MS, and IRMS). The gaseous compounds from experiments consisted of CO2 and C1 to C4 hydrocarbons. Semiquantitative analysis indicates the yield of n-alkanes decreases with carbon number, with CO2 being more abundant than all alkanes. The δ13C value of alkanes increases with molecular weight, with CO2 having the highest value. Methane and ethane become enriched in 13C with time. In bitumen products, gravimetric analysis has shown that the abundance of aromatics increases with time, while that of asphaltenes decreases. After 72 hours, the weight percentages of saturated hydrocarbons, aromatics, resins and asphaltenes are 2.6, 42.3, 40.1, and 15.0, respectively. High resolution GC-MS results indicate low kerogen maturation after 72 hours using saturated biomarker compounds as thermal maturity indicator, such as 22S/(22S + 22R) of C31 to C35 homohopanes, tricyclics/17(H)-hopanes, and Ts/(Ts + Tm). Bulk carbon isotope value of bitumen decreases with time, with 2.5‰ lighter than original kerogen after 72 hours. In terms of different groups, saturated hydrocarbons and resins become depleted in 13C with longer reaction time, while aromatics and asphaltenes become enriched in 13C

  9. Static elasticity of cordierite I: Effect of heavy ion irradiation on the compressibility of hydrous cordierite

    NASA Astrophysics Data System (ADS)

    Miletich, R.; Scheidl, K. S.; Schmitt, M.; Moissl, A. P.; Pippinger, T.; Gatta, G. D.; Schuster, B.; Trautmann, C.

    2014-09-01

    The effect of ion beam irradiations on the elastic properties of hydrous cordierite was investigated by means of Raman and X-ray diffraction experiments. Oriented single crystals were exposed to swift heavy ions (Au, Bi) of various specific energies (10.0-11.1 MeV/u and 80 MeV/u), applying fluences up to 5 × 1013 ions/cm2. The determination of unit-cell constants yields a volume strain of 3.4 × 10-3 up to the maximum fluence, which corresponds to a compression of non-irradiated cordierite at ~480 ± 10 MPa. The unit-cell contraction is anisotropic ( e 1 = 1.4 ± 0.1 × 10-3, e 2 = 1.5 ± 0.1 × 10-3, and e 3 = 7 ± 1 × 10-4) with the c-axis to shrink only half as much as the axes within the ab-plane. The lattice elasticity for irradiated cordierite ( ϕ = 1 × 1012 ions/cm2) was determined from single-crystal XRD measurements in the diamond anvil cell. The fitted third-order Birch-Murnaghan equation-of-state parameters of irradiated cordierite ( V 0 = 1548.41 ± 0.16 Å3, K 0 = 117.1 ± 1.1 GPa, ∂ K/∂ P = -0.6 ± 0.3) reveal a 10-11 % higher compressibility compared to non-irradiated cordierite. While the higher compressibility is attributed to the previously reported irradiation-induced loss of extra-framework H2O, the anomalous elasticity as expressed by elastic softening ( β {a/-1}, β {b/-1}, β {c/-1} = 397 ± 9, 395 ± 28, 308 ± 11 GPa, ∂( β -1)/∂ P = -4.5 ± 2.7, -6.6 ± 8.4, -5.4 ± 3.0) appears to be related to the framework stability and to be independent of the water content in the channels and thus of the ion beam exposure.

  10. Si and O self-diffusion in hydrous forsterite and iron-bearing olivine from the perspective of defect chemistry

    NASA Astrophysics Data System (ADS)

    Fei, Hongzhan; Katsura, Tomoo

    2016-02-01

    We discuss the experimental results of silicon and oxygen self-diffusion coefficients in forsterite and iron-bearing olivine from the perspective of defect chemistry. Silicon diffusion is dominated by VO ··-associated VSi″″, whereas oxygen diffusion is dominated by hopping of VO ·· under anhydrous conditions, and by (OH)O · under hydrous conditions. By considering the charge neutrality condition of [(OH)O ·] = 2[VMe″] in hydrous forsterite and iron-bearing olivine, we get D Si ∝ (C_{{{{H}}2 {{O}}}})1/3 and D O ∝ (C_{{{{H}}2 {{O}}}})0, which explains the experimental results of water effects on oxygen and silicon self-diffusion rates (Fei et al. in Nature 498:213-215, 2013; J Geophys Res 119:7598-7606, 2014). The C_{{{{H}}2 {{O}}}} dependence of creep rate in the Earth's mantle should be close to that given by Si and O self-diffusion coefficients obtained under water unsaturated conditions.

  11. Phase relations in the hydrous CMAS pyrolite in presence of KCl at 2 GPa

    NASA Astrophysics Data System (ADS)

    Safonov, O.

    2012-04-01

    In the upper mantle, chlorides are constituents of concentrated aqueous solutions (brines), as well as chloride-carbonate and carbonatite melts. Mineral assemblages coming from diverse depth levels show that mobile (K, Na)Cl-bearing fluids are able to provoke intensive metasomatism of the peridotitic mantle accompanied by melting. Scarce experimental studies on influence of brines on mineral equilibria in the peridotitic mantle (Stalder et al., 2008; Chu et al., 2011) indicate that influence of chlorides on water activity in a fluid equilibrated with forsterite enstatite at pressures above 2 GPa is very similar to their effect at lower "crustal" pressures (e.g. Aranovich, Newton, 1997): decrease of the H2O activity with an increase of the salt content results in an increase of the melting temperature of silicates. Nevertheless, these experiments were performed in the Al-free systems. Presence of Al would provoke an active interaction of alkali chlorides, namely KCl, with silicates with formation of new K-Al-bearing phases, such as phlogopite (in presence of H2O), which would influence on the melting of complex assemblages. In order to investigate an effect of KCl on phase relations in the Al2O3, CaO, Na2O-rich hydrous peridotite and on stability of garnet, pyroxenes, and amphiboles, in particular, experiments on interaction of the model CMAS pyrolite Fo57En17Prp14Di12 (+0.3 wt. % of Na2O) with the H2O-KCl fluid were performed at 2 GPa in the temperature interval 900-1200. Mixtures of synthetic forsterite, diopside, enstatite and pyrope in the above weight ratio were mixed with 14 wt. % of Mg(OH)2 corresponding to 4.4 wt. % of H2O in the system. 2.4, 3.7, 5 and 10 wt. % of KCl were added to silicate-H2O mixture. Experiments were performed using a piston-cylinder apparatus with ½-inch talc high-pressure cells calibrated via brucite = periclase + H2O and albite = jadeite + quartz equilibria curves. Temperature was controlled with accuracy ?1 with the W95Re5/W80Re20

  12. Ultrathin inorganic molecular nanowire based on polyoxometalates

    PubMed Central

    Zhang, Zhenxin; Murayama, Toru; Sadakane, Masahiro; Ariga, Hiroko; Yasuda, Nobuhiro; Sakaguchi, Norihito; Asakura, Kiyotaka; Ueda, Wataru

    2015-01-01

    The development of metal oxide-based molecular wires is important for fundamental research and potential practical applications. However, examples of these materials are rare. Here we report an all-inorganic transition metal oxide molecular wire prepared by disassembly of larger crystals. The wires are comprised of molybdenum(VI) with either tellurium(IV) or selenium(IV): {(NH4)2[XMo6O21]}n (X=tellurium(IV) or selenium(IV)). The ultrathin molecular nanowires with widths of 1.2 nm grow to micrometre-scale crystals and are characterized by single-crystal X-ray analysis, Rietveld analysis, scanning electron microscopy, X-ray photoelectron spectroscopy, ultraviolet–visible spectroscopy, thermal analysis and elemental analysis. The crystals can be disassembled into individual molecular wires through cation exchange and subsequent ultrasound treatment, as visualized by atomic force microscopy and transmission electron microscopy. The ultrathin molecular wire-based material exhibits high activity as an acid catalyst, and the band gap of the molecular wire-based crystal is tunable by heat treatment. PMID:26139011

  13. Global inorganic source of atmospheric bromine.

    PubMed

    Enami, S; Vecitis, C D; Cheng, J; Hoffmann, M R; Colussi, A J

    2007-09-13

    A few bromine molecules per trillion (ppt) causes the complete destruction of ozone in the lower troposphere during polar spring and about half of the losses associated with the "ozone hole" in the stratosphere. Recent field and aerial measurements of the proxy BrO in the free troposphere suggest an even more pervasive global role for bromine. Models, which quantify ozone trends by assuming atmospheric inorganic bromine (Bry) stems exclusively from long-lived bromoalkane gases, significantly underpredict BrO measurements. This discrepancy effectively implies a ubiquitous tropospheric background level of approximately 4 ppt Bry of unknown origin. Here, we report that I- efficiently catalyzes the oxidation of Br- and Cl- in aqueous nanodroplets exposed to ozone, the everpresent atmospheric oxidizer, under conditions resembling those encountered in marine aerosols. Br- and Cl-, which are rather unreactive toward O3 and were previously deemed unlikely direct precursors of atmospheric halogens, are readily converted into IBr2- and ICl2- en route to Br2(g) and Cl2(g) in the presence of I-. Fine sea salt aerosol particles, which are predictably and demonstrably enriched in I- and Br-, are thus expected to globally release photoactive halogen compounds into the atmosphere, even in the absence of sunlight. PMID:17713895

  14. INORGANIC PYROPHOSPHATASE OF DESULFOVIBRIO DESULFURICANS.

    PubMed

    AKAGI, J M; CAMPBELL, L L

    1963-09-01

    Akagi, J. M. (University of Illinois, Urbana) and L. Leon Campbell. Inorganic pyrophosphatase of Desulfovibrio desulfuricans. J. Bacteriol. 86:563-568. 1963.-The inorganic pyrophosphatase of Desulfovibrio desulfuricans was purified 136-fold by (NH(4))(2)SO(4) and ethanol fractionation and diethylaminoethyl cellulose chromatography. Mg(++) or Mn(++) was required for optimal activity; Co(++) was only 65% as effective as Mg(++). The optimal ratio of Mg(++) to pyrophosphate was 1.0 at pH 8.0. The K(s) for the pyrophosphatase was found to be in the region of 1.9 x 10(-3)m. Sulfhydryl inhibitors and sodium fluoride had no effect on enzyme activity at a concentration of 10(-3)m. The purified enzyme did not hydrolyze adenosine triphosphate, glycerol phosphate, diphenyl phosphate, or p-nitrophenyl phosphate. Thermal stability studies showed that the enzyme is rapidly inactivated at temperatures above 40 C. PMID:14066437

  15. Gas separations using inorganic membranes

    SciTech Connect

    Egan, B.Z.; Singh, S.P.N. ); Fain, D.E.; Roettger, G.E.; White, D.E. )

    1992-04-01

    This report summarizes the results from a research and development program to develop, fabricate, and evaluate inorganic membranes for separating gases at high temperatures and pressures in hostile process environments encountered in fossil energy conversion processes such as coal gasification. The primary emphasis of the research was on the separation and recovery of hydrogen from synthesis gas. Major aspects of the program included assessment of the worldwide research and development activity related to gas separations using inorganic membranes, identification and selection of candidate membrane materials, fabrication and characterization of membranes using porous membrane technology developed at the Oak Ridge K-25 Site, and evaluation of the separations capability of the fabricated membranes in terms of permeabilities and fluxes of gases.

  16. Hybrid polymer-inorganic nanocomposites

    NASA Astrophysics Data System (ADS)

    Pomogailo, Anatolii D.

    2000-01-01

    Approaches to the preparation of organic-inorganic nanocomposites are considered from a unified viewpoint for the first time. The major problems in the development of this new line of research in materials technology, which has arisen on the border of the science of polymers, colloid chemistry and physical chemistry of the ultradisperse state, are discussed. The main methods for the formation of composite materials and polymer-inorganic cross-linked hybrids with interpenetrating networks are analysed. Primary attention is given to sol-gel procedures for their preparation, including template processes, which occur under conditions of strict stereochemical orientation of reactants, intercalation of monomers and polymers into porous and layered matrices and their intracrystalline and post-intercalation transformations. Methods for the synthesis and properties of metallopolymeric polymolecular Langmuir-Blodgett films, which are peculiar supramolecular ensembles incorporating nanosized metal-containing particles, are discussed. The generality of the processes of formation of organic-inorganic nanocomposites in living and nonliving natural objects is demonstrated and the major fields of application of nanocomposites are considered. The bibliography includes 566 references.

  17. Aqueous alteration on the parent bodies of carbonaceous chondrites: Computer simulations of late-stage oxidation

    NASA Technical Reports Server (NTRS)

    Bourcier, W. L.; Zolensky, Michael E.

    1991-01-01

    CI carbonaceous chondrites may be products of hydrous alteration of CV- or anhydrous CM-type materials. The CIs typically contain veins filled with carbonates and sulfates, probably indicating a period of late stage aqueous alteration under oxidizing conditions. To test this idea, computer simulations of aqueous alteration of CV- and CM-type carbonaceous were performed. Simulations were restricted to the oxidation of hydrous mineral assemblages produced in previous simulations in order to determine whether further reaction and oxidation results in the phyllosilicate, carbonate, sulfate and oxide vein assemblages typical of CI carbonaceous chondrites. Our simulations were performed at 1, 25, 100, and 150 C (the appropriate temperature range) for the CV and CM mineral assemblages and using the computer code EQ3/6.

  18. Detection and removal of dissolved hydrogen sulphide in flow-through systems via the sulphidation of hydrous iron (III) oxides.

    PubMed

    Poulton, S W; Krom, M D; van Rijn, J; Raiswell, R; Bows, R

    2003-02-01

    A novel automated warning and removal system for hydrogen sulphide in aqueous flow-through systems has been developed based on the sulphidation of ferrihydrite sorbed to zeolite substrate. The system consists of a small flow-through reaction cartridge with photo-sensors positioned at the base. During the reaction, sulphide is initially oxidised to elemental sulphur by the ferrihydrite, and Fe2+ is subsequently released to solution. This Fe2+ then reacts with additional dissolved sulphide to form solid phase iron monosulphide. The colour change from orange ferrihydrite to black iron monosulphide is continuously monitored by the photo-sensors, which provide a rapid and reproducible response (via a voltage change) to pulses of sulphidic water. The response of the photo-sensors is linear with respect to inflowing sulphide concentration, while the most rapid response to dissolved sulphide occurs at a flow rate of approximately 200 ml min(-1) (equivalent to a hydraulic loading rate of 21 cm min(-1). The presence of phosphate in solution substantially decreases reaction rates due to adsorption to reactive surface sites. However, the response time of the photo-sensors remains sufficient to provide a rapid indication of sulphidic conditions even in systems with high concentrations of dissolved phosphate. The cartridge has the advantage of partially or completely removing sulphide (depending on flow rate and substrate mass) from an initial pulse of water. At the optimal flow rate for the successful use of the cartridge as a sulphide warning system (200 ml min(-1)), required substrate masses for the complete removal of dissolved sulphide (over the experimental range of 0-1000 microM) are relatively small (0.5-2 kg).

  19. Weathering of Dronino Iron Meteorite and Ferric Hydrous Oxides Transfer in Clay Sand Studied Using Mössbauer Spectroscopy

    NASA Astrophysics Data System (ADS)

    Yakovlev, G. A.; Oshtrakh, M. I.; Semionkin, V. A.

    2016-08-01

    The Dronino meteorite fragments found in clay sand demonstrated heavily weathering. Several concretions formed in this place were also found. These weathering products were subject for the study using Mössbauer spectroscopy.

  20. Silicon oxidation in fluoride solutions

    NASA Technical Reports Server (NTRS)

    Sancier, K. M.; Kapur, V.

    1980-01-01

    Silicon is produced in a NaF, Na2SiF6, and Na matrix when SiF4 is reduced by metallic sodium. Hydrogen is evolved during acid leaching to separate the silicon from the accompanying reaction products, NaF and Na2SiF6. The hydrogen evolution reaction was studied under conditions simulating leaching conditions by making suspensions of the dry silicon powder in aqueous fluoride solutions. The mechanism for the hydrogen evolution is discussed in terms of spontaneous oxidation of silicon resulting from the cooperative effects of (1) elemental sodium in the silicon that reacts with water to remove a protective silica layer, leaving clean reactive silicon, and (2) fluoride in solution that complexes with the oxidized silicon in solution and retards formation of a protective hydrous oxide gel.

  1. Experimental Hydrous Partial Melting of Natural Pristine and Altered MORB Beneath Subduction Zones

    NASA Astrophysics Data System (ADS)

    Carter, L. B.; Skora, S. E.; Blundy, J.

    2012-12-01

    Experimental determination of the hydrous phase relations and trace element partitioning behaviour of Mid-Ocean Ridge Basalt (MORB) constrains the conditions for melting of subducted oceanic crust. This study utilises natural pristine MORB (from the Kolbeinsey ridge, north of Iceland) and altered MORB from the altered oceanic crust (AOC, from the DSDP leg 46, Mid Atlantic, ~20°N), hydrated with about 15wt% water, in experiments using piston-cylinder apparatus to simulate pressures and temperatures equivalent to about 100 km depth (3.0 GPa, 800-1000°C). Our motivation of (re-)studying the melting behaviour of undoped subducted basalt is two-fold. First, previous studies that focused on the trace element behaviour 'doped' their starting materials with trace elements to facilitate analysis and positive identification of accessory phases. Only by applying the 'doping' method has it been found that allanite may exert a key control on the light rare earth element (approx. La-Sm) budget in subducted basalt. However, it is still a matter of debate whether the ubiquitous presence of allanite in these experimental studies is solely due to doping of La-Sm. In addition, bulk fluid-solid partition coefficients so obtained may not be uncritically applied to model the trace element transfer in nature because of the enhanced proportions of accessory phases in the experimental solid residue. Second, there appears to be a clear difference in the melting behaviour of K-free and K-bearing MORB (and sediment), even if K2O only appears in minor concentrations. These differences are difficult to quantify, as the various studies were carried out at differing P-T-XH2O conditions. In agreement with earlier studies, we find that the vapour-saturated solidus is shifted toward higher temperatures at 3 GPa in pristine MORB (800°C < Tsolidus < 850°C), because it is virtually K-free (approx. 0.03 wt% K2O), in contrast to altered MORB where melting starts at T < 800°C (approx. 0.26 wt% K2O

  2. Correlating single-molecule and ensemble-average measurements of peptide adsorption onto different inorganic materials.

    PubMed

    Kim, Seong-Oh; Jackman, Joshua A; Mochizuki, Masahito; Yoon, Bo Kyeong; Hayashi, Tomohiro; Cho, Nam-Joon

    2016-06-01

    The coating of solid-binding peptides (SBPs) on inorganic material surfaces holds significant potential for improved surface functionalization at nano-bio interfaces. In most related studies, the goal has been to engineer peptides with selective and high binding affinity for a target material. The role of the material substrate itself in modulating the adsorption behavior of a peptide molecule remains less explored and there are few studies that compare the interaction of one peptide with different inorganic substrates. Herein, using a combination of two experimental techniques, we investigated the adsorption of a 16 amino acid-long random coil peptide to various inorganic substrates - gold, silicon oxide, titanium oxide and aluminum oxide. Quartz crystal microbalance-dissipation (QCM-D) experiments were performed in order to measure the peptide binding affinity for inorganic solid supports at the ensemble average level, and atomic force microscopy (AFM) experiments were conducted in order to determine the adhesion force of a single peptide molecule. A positive trend was observed between the total mass uptake of attached peptide and the single-molecule adhesion force on each substrate. Peptide affinity for gold was appreciably greater than for the oxide substrates. Collectively, the results obtained in this study offer insight into the ways in which inorganic materials can differentially influence and modulate the adhesion of SBPs.

  3. Correlating single-molecule and ensemble-average measurements of peptide adsorption onto different inorganic materials.

    PubMed

    Kim, Seong-Oh; Jackman, Joshua A; Mochizuki, Masahito; Yoon, Bo Kyeong; Hayashi, Tomohiro; Cho, Nam-Joon

    2016-06-01

    The coating of solid-binding peptides (SBPs) on inorganic material surfaces holds significant potential for improved surface functionalization at nano-bio interfaces. In most related studies, the goal has been to engineer peptides with selective and high binding affinity for a target material. The role of the material substrate itself in modulating the adsorption behavior of a peptide molecule remains less explored and there are few studies that compare the interaction of one peptide with different inorganic substrates. Herein, using a combination of two experimental techniques, we investigated the adsorption of a 16 amino acid-long random coil peptide to various inorganic substrates - gold, silicon oxide, titanium oxide and aluminum oxide. Quartz crystal microbalance-dissipation (QCM-D) experiments were performed in order to measure the peptide binding affinity for inorganic solid supports at the ensemble average level, and atomic force microscopy (AFM) experiments were conducted in order to determine the adhesion force of a single peptide molecule. A positive trend was observed between the total mass uptake of attached peptide and the single-molecule adhesion force on each substrate. Peptide affinity for gold was appreciably greater than for the oxide substrates. Collectively, the results obtained in this study offer insight into the ways in which inorganic materials can differentially influence and modulate the adhesion of SBPs. PMID:27174015

  4. Inorganics

    SciTech Connect

    Qureshi, M.

    1986-01-01

    This comprehensive handbook is valuable when doing routine analysis or developing new methods of chromatography of organic materials. Section I presents the principles, techniques, quantitative determinations and detection methods used in chromatographic analysis. In the major part of the book, Section II summarizes data in voluminous tabular/graphic form on paper, thin layer, liquid and gas chromatography. Section III lists important books on electrophoresis, gel permeation chromatography, and ion exchange, in addition to the other forms of chromatography mentioned above.

  5. Inorganic-organic materials incorporating alumoxane nanoparticles

    NASA Astrophysics Data System (ADS)

    Vogelson, Cullen Taylor

    Chemically functionalized alumina nanoparticles (carboxylate-alumoxanes) are used as the inorganic component of a new class of inorganic-organic material. Lysine- or para-hydroxybenzoic acid-derivatized alumoxanes are prepared from the reaction of boehmite, [Al(O)(OH)]n, with the appropriate carboxylic acid. The peripheral hydroxides and amines of these alumoxanes react directly with DER 332 epoxide to form a hybrid material, or in the presence of a resin and hardener system, to form a composite material. Solid state NMR spectroscopy demonstrates that the alumoxanes are chemically bound to the resin matrix. The properties and cure times of the alumoxane materials are distinct from both the pure resins and from a physical blend of the resins with traditional fillers. A significant increase in thermal stability and tensile strength is observed for the resin systems. In order to produce molecular coupling layers, epoxides cross-linked with self-assembled monolayers (SAMs) grown on the native oxide of aluminum thin films on silicon substrates have been investigated. Specifically, SAMs have been formed by the attachment of different carboxylic acids. In order to investigate the cross-linking reaction between carboxylate monolayers and an epoxide, grown monolayers were reacted with a mono-epoxy resin. In addition to these surface materials, aluminum oxide surfaces supporting carboxylate monolayers were reacted in pairs with DER 332 to form a structural adhesive. These materials have been characterized variously by SEM, AFM, XPS, EDX, and contact angle measurements. The particle size dependence on pH of a series of alumoxanes was investigated. For each of the alumoxanes, PCS particle size measurements were obtained as a function of pH. In all cases, particle size control was afforded by variations in pH. Finally, crystal structures of several model compounds were determined by X-ray crystallography, and shown to form either sheets of dimers or tetrameric units. Through a

  6. Hierarchical Inorganic Assemblies for Artificial Photosynthesis.

    PubMed

    Kim, Wooyul; Edri, Eran; Frei, Heinz

    2016-09-20

    Artificial photosynthesis is an attractive approach for renewable fuel generation because it offers the prospect of a technology suitable for deployment on highly abundant, non-arable land. Recent leaps forward in the development of efficient and durable light absorbers and catalysts for oxygen evolution and the growing attention to catalysts for carbon dioxide activation brings into focus the tasks of hierarchically integrating the components into assemblies for closing of the photosynthetic cycle. A particular challenge is the efficient coupling of the multi-electron processes of CO2 reduction and H2O oxidation. Among the most important requirements for a complete integrated system are catalytic rates that match the solar flux, efficient charge transport between the various components, and scalability of the photosynthetic assembly on the unprecedented scale of terawatts in order to have impact on fuel consumption. To address these challenges, we have developed a heterogeneous inorganic materials approach with molecularly precise control of light absorption and charge transport pathways. Oxo-bridged heterobinuclear units with metal-to-metal charge-transfer transitions absorbing deep in the visible act as single photon, single charge transfer pumps for driving multi-electron catalysts. A photodeposition method has been introduced for the spatially directed assembly of nanoparticle catalysts for selective coupling to the donor or acceptor metal of the light absorber. For CO2 reduction, a Cu oxide cluster is coupled to the Zr center of a ZrOCo light absorber, while coupling of an Ir nanoparticle catalyst for water oxidation to the Co donor affords closing of the photosynthetic cycle of CO2 conversion by H2O to CO and O2. Optical, vibrational, and X-ray spectroscopy provide detailed structural knowledge of the polynuclear assemblies. Time resolved visible and rapid-scan FT-IR studies reveal charge transfer mechanisms and transient surface intermediates under

  7. Hierarchical Inorganic Assemblies for Artificial Photosynthesis.

    PubMed

    Kim, Wooyul; Edri, Eran; Frei, Heinz

    2016-09-20

    Artificial photosynthesis is an attractive approach for renewable fuel generation because it offers the prospect of a technology suitable for deployment on highly abundant, non-arable land. Recent leaps forward in the development of efficient and durable light absorbers and catalysts for oxygen evolution and the growing attention to catalysts for carbon dioxide activation brings into focus the tasks of hierarchically integrating the components into assemblies for closing of the photosynthetic cycle. A particular challenge is the efficient coupling of the multi-electron processes of CO2 reduction and H2O oxidation. Among the most important requirements for a complete integrated system are catalytic rates that match the solar flux, efficient charge transport between the various components, and scalability of the photosynthetic assembly on the unprecedented scale of terawatts in order to have impact on fuel consumption. To address these challenges, we have developed a heterogeneous inorganic materials approach with molecularly precise control of light absorption and charge transport pathways. Oxo-bridged heterobinuclear units with metal-to-metal charge-transfer transitions absorbing deep in the visible act as single photon, single charge transfer pumps for driving multi-electron catalysts. A photodeposition method has been introduced for the spatially directed assembly of nanoparticle catalysts for selective coupling to the donor or acceptor metal of the light absorber. For CO2 reduction, a Cu oxide cluster is coupled to the Zr center of a ZrOCo light absorber, while coupling of an Ir nanoparticle catalyst for water oxidation to the Co donor affords closing of the photosynthetic cycle of CO2 conversion by H2O to CO and O2. Optical, vibrational, and X-ray spectroscopy provide detailed structural knowledge of the polynuclear assemblies. Time resolved visible and rapid-scan FT-IR studies reveal charge transfer mechanisms and transient surface intermediates under

  8. Survey of electrochemical production of inorganic compounds. Final report

    SciTech Connect

    Not Available

    1980-10-01

    The electrochemical generation of inorganic compounds, excluding chlorine/caustic, has been critically reviewed. About 60 x 10/sup 12/ Btu/y fossil fuel equivalent will be used in the year 2000 for the electrosynthesis of inorganic compounds. Significant energy savings in chlorate production can result from the development of suitable electrocatalysts for lowering the cathodic overpotential. Perchlorates, electrolytic hypochlorite, electrolytic manganese dioxide, fluorine and other miscellaneous compounds use relatively small amounts of electrical energy. Implementation of caustic scrubber technology for stack gas cleanup would result in appreciable amounts of sodium sulfate which could be electrolyzed to regenerate caustic. Hydrogen peroxide, now produced by the alkyl anthraquinone process, could be made electrolytically by a new process coupling anodic oxidation of sulfate with cathodic reduction of oxygen in alkaline solution. Ozone is currently manufactured using energy-inefficient silent discharge equipment. A novel energy-efficient approach which uses an oxygen-enhanced anodic reaction is examined.

  9. Strongly coupled inorganic/nanocarbon hybrid materials for advanced electrocatalysis.

    PubMed

    Liang, Yongye; Li, Yanguang; Wang, Hailiang; Dai, Hongjie

    2013-02-13

    Electrochemical systems, such as fuel cell and water splitting devices, represent some of the most efficient and environmentally friendly technologies for energy conversion and storage. Electrocatalysts play key roles in the chemical processes but often limit the performance of the entire systems due to insufficient activity, lifetime, or high cost. It has been a long-standing challenge to develop efficient and durable electrocatalysts at low cost. In this Perspective, we present our recent efforts in developing strongly coupled inorganic/nanocarbon hybrid materials to improve the electrocatalytic activities and stability of inorganic metal oxides, hydroxides, sulfides, and metal-nitrogen complexes. The hybrid materials are synthesized by direct nucleation, growth, and anchoring of inorganic nanomaterials on the functional groups of oxidized nanocarbon substrates including graphene and carbon nanotubes. This approach affords strong chemical attachment and electrical coupling between the electrocatalytic nanoparticles and nanocarbon, leading to nonprecious metal-based electrocatalysts with improved activity and durability for the oxygen reduction reaction for fuel cells and chlor-alkali catalysis, oxygen evolution reaction, and hydrogen evolution reaction. X-ray absorption near-edge structure and scanning transmission electron microscopy are employed to characterize the hybrids materials and reveal the coupling effects between inorganic nanomaterials and nanocarbon substrates. Z-contrast imaging and electron energy loss spectroscopy at single atom level are performed to investigate the nature of catalytic sites on ultrathin graphene sheets. Nanocarbon-based hybrid materials may present new opportunities for the development of electrocatalysts meeting the requirements of activity, durability, and cost for large-scale electrochemical applications.

  10. Inorganic Components of Atmospheric Aerosols

    NASA Astrophysics Data System (ADS)

    Wexler, Anthony Stein

    The inorganic components comprise 15% to 50% of the mass of atmospheric aerosols. For about the past 10 years the mass of these components was predicted assuming thermodynamic equilibrium between the volatile aerosol -phase inorganic species NH_4NO _3 and NH_4Cl and their gas-phase counterparts NH_3, HNO_3, and HCl. In this thesis I examine this assumption and prove that (1) the time scales for equilibration between the gas and aerosol phases are often too long for equilibrium to hold, and (2) even when equilibrium holds, transport considerations often govern the size distribution of these aerosol components. Water can comprise a significant portion of atmospheric aerosols under conditions of high relative humidity, whereas under conditions of sufficiently low relative humidity atmospheric aerosols tend to be dry. The deliquescence point is the relative humidity where the aerosol goes from a solid dry phase to an aqueous or mixed solid-aqueous phase. In this thesis I derive the temperature dependence of the deliquescence point and prove that in multicomponent solutions the deliquescence point is lower than for corresponding single component solutions. These theories of the transport, thermodynamic, and deliquescent properties of atmospheric aerosols are integrated into an aerosol inorganics model, AIM. The predictions of AIM compare well to fundamental thermodynamic measurements. Comparison of the prediction of AIM to those of other aerosol equilibrium models shows substantial disagreement in the predicted water content at lower relative humidities. The disagreement is due the improved treatment in AIM of the deliquescence properties of multicomponent solutions. In the summer and fall of 1987 the California Air Resources Board conducted the Southern California Air Quality Study, SCAQS, during which atmospheric aerosols were measured in Los Angeles. The size and composition of the aerosol and the concentrations of their gas phase counterparts were measured. When the

  11. Inorganic Nanoparticles in Cancer Therapy

    PubMed Central

    Bhattacharyya, Sanjib; Kudgus, Rachel A.; Bhattacharya, Resham; Mukherjee, Priyabrata

    2011-01-01

    Nanotechnology is an evolving field with enormous potential for biomedical applications. The growing interest to use inorganic nanoparticles in medicine is due to the unique size and shape-dependent optoelectronic properties. Herein, we will focus on gold, silver and platinum nanoparticles, discussing recent developments for therapeutic applications with regard to cancer in terms of nanoparticles being used as a delivery vehicle as well as therapeutic agents. We will also discuss some of the key challenges to be addressed in future studies. PMID:21104301

  12. The inorganic constituents of echinoderms

    USGS Publications Warehouse

    Clarke, F.W.; Wheeler, W.C.

    1915-01-01

    In a recent paper on the composition of crinoid skeletons we showed that crinoids contain large quantities of magnesia, and that its proportion varies with the temperature of the water in which the creatures live. This result was so novel and surprising that it seemed desirable to examine other echinoderms and to ascertain whether they showed the same characteristics and regularity. A number of sea urchins and starfishes were therefore studied, their inorganic constituents being analyzed in the same manner as those of the crinoids

  13. AFM studies of semicrystalline polymer/inorganic nanocomposites

    NASA Astrophysics Data System (ADS)

    Strawhecker, Kenneth E.

    2002-01-01

    The aims of this work are to elucidate the effects of interaction strength on the crystallization of a polymer near an inorganic surface; connect filler induced polymer crystallinity with resulting property changes, especially for strongly interacting (i.e. hydrogen bonding) systems; and to devise atomic force microscopy (AFM) methods for probing the crystallinity and properties of polymer/layered silicate systems at the nanometer level. Three inorganically filled systems were studied: (1) poly(vinyl alcohol) (PVA), (2) poly(ethylene oxide) (PEO), and (3) polypropylene (PP). Since it has the strongest, interactions, the PVA system is investigated first. AFM is used in conjunction with x-ray diffraction and differential scanning calorimetry (DSC) to show that strong polymer/filler interactions can promote a different crystalline structure and a different morphology than those seen in the bulk. The study then proceeds to the weakly interacting PEO/inorganic system where it is found that the inorganic layers disrupt crystalline morphology, but do not change the crystal structure. Furthermore, crystallization always occurs in volumes away from the inorganic filler. The third system (neutral interactions), PP/inorganic is then discussed. The three systems are compared with each other, and is found that the crystalline morphology and structure is highly dependent upon the strength of interaction between the polymer and filler. Due to its far-reaching morphology changes, the strongly interacting system was chosen for property studies. The composite structure study revealed a coexistence of exfoliated and intercalated MMT layers, especially for low and moderate silicate loadings. The inorganic layers promote a new crystalline phase different than the one of the respective neat PVA, characterized by higher melting temperature and a different crystal structure. This new crystal phase reflects on the composite materials properties, which have mechanical, thermal, and water

  14. Sulfur solubility in hydrous Etna Basalt at temperatures from 1150 to 1250 °C and 200 MPa

    NASA Astrophysics Data System (ADS)

    Beermann, O.; Nowak, N.; Botcharnikov, R. E.; Holtz, F.

    2009-04-01

    Degassing of magmatic volatiles is strongly dependent on fluid-melt interaction at the oneset of degassing under given pressure and temperature. Most magmatic fluids are composed of hydrous multicomponental mixtures, e.g. H-O-C-S-Cl-F-Br bearing fluids. In particular the partitioning behaviour of S and Cl between basaltic melt and hydrous fluid is of interest, because the S/Cl ratio of emitted volcanic gasses correlate to the eruption style (e.g. [1], [2], [3]). In particular, this was also observed for the 2002 eruption of Mt. Etna (Sicily) [4], which is one of the worlds most active and best investigated volcanoes. Since now, there even exist no reliable data on the solubility of sulfur in hydrous silicic melts at geologic relevant temperatures for basaltic magmas (above 1050 °C), because sulfur is known to be a very aggressive component limiting the application of experimental approaches that use noble metal capsules, especially Pt and AuPd. Thus, the experiments in this study, concerning the solubility of S in natural hydrous Etna basalt at 200 MPa and temperatures from 1150 to 1250 °C at fO2 ~ NNO + 2.5 and 1200 °C at fO2 ~ NNO, were performed in olivine-AuPd double capsules, using single crystal olivine capsules (San Carlos olivine) as sample containers, which were inserted into outer Au80Pd20 capsules. The starting material was a fused and water presaturated trachybasalt from Mt. Etna (2001 eruption), containing 5 wt.% H2O. For sulfur source pyrrhotine (FeS) was used, obtaining initial S concentrations between 1-1.5 wt.% (with respect to the amount of starting material). For some experiments an olivine disc was placed between FeS and starting glass powder to avoid FeS dispersion in the melt. All experiments were conducted in internally heated argon pressure vessels (IHPV) equipped with rapid quench device. For the reduced runs an Ar-H2 mixture was load into the vessel and the H2 pressure was monitored, using the shaw membrane technique. The experimental

  15. Experimental controls on D/H and 13C/12C ratios of kerogen, bitumen and oil during hydrous pyrolysis

    USGS Publications Warehouse

    Schimmelmann, A.; Boudou, J.-P.; Lewan, M.D.; Wintsch, R.P.

    2001-01-01

    Large isotopic transfers between water-derived hydrogen and organic hydrogen occurred during hydrous pyrolysis experiments of immature source rocks, in spite of only small changes in organic 13C/12C. Experiments at 330 ??C over 72 h using chips or powder containing kerogen types I and III identify the rock/water ratio as a main factor affecting ????D for water and organic hydrogen. Our data suggest that larger rock permeability and smaller rock grain size increase the H-isotopic transfer between water-derived hydrogen and thermally maturing organic matter. Increasing hydrostatic pressure may have a similar effect, but the evidence remains inconclusive. ?? 2001 Elsevier Science Ltd. All rights reserved.

  16. Ancient and recent clay formation on Mars as revealed from a global survey of hydrous minerals in crater central peaks

    NASA Astrophysics Data System (ADS)

    Sun, Vivian Z.; Milliken, Ralph E.

    2015-12-01

    Clay minerals on Mars have commonly been interpreted as the remnants of pervasive water-rock interaction during the Noachian period (>3.7 Ga). This history has been partly inferred by observations of clays in central peaks of impact craters, which often are presumed uplifted from depth. However, combined mineralogical and morphological analyses of individual craters have shown that some central peak clays may represent post-impact, possibly authigenic processes. Here we present a global survey of 633 central peaks to assess their hydrous minerals and the prevalence of uplifted, detrital, and authigenic clays. Central peak regions are examined using high-resolution Compact Reconnaissance Imaging Spectrometer for Mars and High Resolution Imaging Science Experiment data to identify hydrous minerals and place their detections in a stratigraphic and geologic context. We find that many occurrences of Fe/Mg clays and hydrated silica are associated with potential impact melt deposits. Over 35% of central peak clays are not associated with uplifted rocks; thus, caution must be used when inferring deeper crustal compositions from surface mineralogy of central peaks. Uplifted clay-bearing rocks suggest the Martian crust hosts clays to depths of at least 7 km. We also observe evidence for increasing chloritization with depth, implying the presence of fluids in the upper portions of the crust. Our observations are consistent with widespread Noachian/Early Hesperian clay formation, but a number of central peak clays are also suggestive of clay formation during the Amazonian. These results broadly support current paradigms of Mars' aqueous history while adding insight to global crustal and diagenetic processes associated with clay mineral formation and stability.

  17. Release of sulfur- and oxygen-bound components from a sulfur-rich kerogen during simulated maturation by hydrous pyrolysis

    USGS Publications Warehouse

    Putschew, A.; Schaeffer-Reiss, C.; Schaeffer, P.; Koopmans, M.P.; De Leeuw, J. W.; Lewan, M.D.; Sinninghe, Damste J.S.; Maxwell, J.R.

    1998-01-01

    An immature sulfur-rich marl from the Gessosso-solfifera Formation of the Vena del Gesso Basin (Messinian, Italy) has been subjected to hydrous pyrolysis (160 to 330??C) to simulate maturation under natural conditions. The kerogen of the unheated and heated samples was isolated and the hydrocarbons released by selective chemical degradation (Li/EtNH2 and HI/LiAIH4) were analysed to allow a study of the fate of sulfur- and oxygen-bound species with increasing temperature. The residues from the chemical treatments were also subjected to pyrolysis-GC to follow structural changes in the kerogens. In general, with increasing hydrous pyrolysis temperature, the amounts of sulfide- and ether-bound components in the kerogen decreased significantly. At the temperature at which the generation of expelled oil began (260??C), almost all of the bound components initially present in the unheated sample were released from the kerogen. Comparison with an earlier study of the extractable organic matter using a similar approach and the same samples provides molecular evidence that, with increasing maturation, solvent-soluble macromolecular material was initially released from the kerogen, notably as a result of thermal cleavage of weak Carbon-heteroatom bonds (sulfide, ester, ether) even at temperatures as low as 220??C. This solvent-soluble macromolecular material then underwent thermal cleavage to generate hydrocarbons at higher temperatures. This early generation of bitumen may explain the presence of unusually high amounts of extractable organic matter of macromolecular nature in very immature S-rich sediments.

  18. Can Minor Hydrous Minerals Play a Role in Low Crust Seismic Anisotropy: an Experimental and Numerical Investigation to Finero Peridotites

    NASA Astrophysics Data System (ADS)

    Zhong, X.; Kunze, K.; Zappone, A. S.

    2013-12-01

    The Ivrea-Verbano Zone (South-Alpine basement, NW Italy) offers an unique opportunity to study lower crust/upper mantle rocks unaffected by serpentinization or intense weathering. Peridotites from Finero (northeast Ivrea-Verbano Zone) have been collected to investigate the physical influence , on seismic properties of hydrous minerals (hornblende and phlogopite), which have been formed as a consequence of metasomatism. The methods involve experimental tests using ultrasound wave measurements at increasing hydrostatic confining pressure, electron backscatter diffraction (EBSD), to investigate the crystallographic preferred orientation and its influence on seismic anisotropy, optical microscope, scanning electron microscope (SEM) together with open software simulation (MTEX and OIM Analysis) to investigate the influence of crystal shape and grain boundaries. The seismic anisotropy of compressional wave range from 2% to 8.7% (averaged around 6%) under room temperature and meanwhile shows decreasing trend as confining pressure increases (from 20 to 250 MPa). However, no distinct crystallographic preferred orientation of major minerals including olivine, orthopyroxene and clinopyroxene have been observed in EBSD and EDX maps. Since the fast axis of metasomatic hornblende and phlogopite are better aligned along the lineation direction, one explanation is that the seismic anisotropy is mainly a result of the preferred orientation of minor hornblende and phlogopite, though they only make around 1~5% percent of the whole content based on SEM images. We propose that the well orientated hydrous minerals can strongly influence the seismic anisotropy in the case where the dominate minerals show weak or no crystallographic preferred orientation. Another possible explanation might be due to the influence of crystal shape and geometrical arrangement of grain boundaries . DBSD inverse pole figure map of sample ZAP201. The grains are mostly olivine showing random orientation. Other

  19. Theoretical and Experimental Studies of the Spin Trapping of Inorganic Radicals by 5,5-Dimethyl-1-Pyrroline N-Oxide (DMPO). 3. Sulfur Dioxide, Sulfite and Sulfate Radical Anions

    PubMed Central

    Zamora, Pedro L.; Villamena, Frederick A.

    2012-01-01

    Radical forms of sulfur dioxide (SO2), sulfite (SO32−), sulfate (SO42−), and their conjugate acids are known to be generated in vivo through various chemical and biochemical pathways. Oxides of sulfur are environmentally pervasive compounds and are associated with a number of health problems. There is growing evidence that their toxicity may be mediated by their radical forms. Electron paramagnetic resonance (EPR) spin trapping using the commonly used spin trap, 5,5-dimethyl-1-pyrroline N-oxide (DMPO), has been employed in the detection of SO3•− and SO4•−. The thermochemistries of SO2•−, SO3•−, SO4•−, and their respective conjugate acids addition to DMPO were predicted using density functional theory (DFT) at the PCM/B3LYP/6-31+G**//B3LYP/6-31G* level. No spin adduct was observed for SO2•− by EPR but an S-centered adduct was observed for SO3•− and an O-centered adduct for SO4•−. Determination of adducts as S- or O-centered was made via comparison based on qualitative trends of experimental hfcc’s with theoretically calculated ones. The thermodynamics of the non-radical addition of SO32− and HSO3− to DMPO followed by conversion to the corresponding radical adduct via the Forrester-Hepburn mechanism was also calculated. Adduct acidities and decomposition pathways were investigated as well, including an EPR experiment using H217O to determine the site of hydrolysis of O-centered adducts. The mode of radical addition to DMPO is predicted to be governed by several factors, including spin population density, and geometries stabilized by hydrogen bonds. The thermodynamic data supports evidence for the radical addition pathway over the nucleophilic addition mechanism. PMID:22668066

  20. XPS determination of Mn oxidation states in Mn (hydr)oxides

    NASA Astrophysics Data System (ADS)

    Ilton, Eugene S.; Post, Jeffrey E.; Heaney, Peter J.; Ling, Florence T.; Kerisit, Sebastien N.

    2016-03-01

    Hydrous manganese oxides are an important class of minerals that help regulate the geochemical redox cycle in near-surface environments and are also considered to be promising catalysts for energy applications such as the oxidation of water. A complete characterization of these minerals is required to better understand their catalytic and redox activity. In this contribution an empirical methodology using X-ray photoelectron spectroscopy (XPS) is developed to quantify the oxidation state of hydrous multivalent manganese oxides with an emphasis on birnessite, a layered structure that occurs commonly in soils but is also the oxidized endmember in biomimetic water-oxidation catalysts. The Mn2p3/2, Mn3p, and Mn3s lines of near monovalent Mn(II), Mn(III), and Mn(IV) oxides were fit with component peaks; after the best fit was obtained the relative widths, heights and binding energies of the components were fixed. Unknown multivalent samples were fit such that binding energies, intensities, and peak-widths of each oxidation state, composed of a packet of correlated component peaks, were allowed to vary. Peak-widths were constrained to maintain the difference between the standards. Both average and individual mole fraction oxidation states for all three energy levels were strongly correlated, with close agreement between Mn3s and Mn3p analyses, whereas calculations based on the Mn2p3/2 spectra gave systematically more reduced results. Limited stoichiometric analyses were consistent with Mn3p and Mn3s. Further, evidence indicates the shape of the Mn3p line was less sensitive to the bonding environment than that for Mn2p. Consequently, fitting the Mn3p and Mn3s lines yielded robust quantification of oxidation states over a range of Mn (hydr)oxide phases. In contrast, a common method for determining oxidation states that utilizes the multiplet splitting of the Mn3s line was found to be not appropriate for birnessites.

  1. Biodegradable and Renal Clearable Inorganic Nanoparticles

    PubMed Central

    Ehlerding, Emily B.; Chen, Feng; Cai, Weibo

    2016-01-01

    Personalized treatment plans for cancer therapy have been at the forefront of oncology research for many years. With the advent of many novel nanoplatforms, this goal is closer to realization today than ever before. Inorganic nanoparticles hold immense potential in the field of nano-oncology, but have considerable toxicity concerns that have limited their translation to date. In this review, an overview of emerging biologically safe inorganic nanoplatforms is provided, along with considerations of the challenges that need to be overcome for cancer theranostics with inorganic nanoparticles to become a reality. The clinical and preclinical studies of both biodegradable and renal clearable inorganic nanoparticles are discussed, along with their implications. PMID:27429897

  2. Biodegradable and Renal Clearable Inorganic Nanoparticles

    PubMed Central

    Ehlerding, Emily B.

    2015-01-01

    Personalized treatment plans for cancer therapy have been at the forefront of oncology research for many years. With the advent of many novel nanoplatforms, this goal is closer to realization today than ever before. Inorganic nanoparticles hold immense potential in the field of nano‐oncology, but have considerable toxicity concerns that have limited their translation to date. In this review, an overview of emerging biologically safe inorganic nanoplatforms is provided, along with considerations of the challenges that need to be overcome for cancer theranostics with inorganic nanoparticles to become a reality. The clinical and preclinical studies of both biodegradable and renal clearable inorganic nanoparticles are discussed, along with their implications. PMID:27429897

  3. Heat-transport mechanisms in molecular building blocks of inorganic/organic hybrid superlattices

    NASA Astrophysics Data System (ADS)

    Giri, Ashutosh; Niemelä, Janne-Petteri; Tynell, Tommi; Gaskins, John T.; Donovan, Brian F.; Karppinen, Maarit; Hopkins, Patrick E.

    2016-03-01

    Nanomaterial interfaces and concomitant thermal resistances are generally considered as atomic-scale planes that scatter the fundamental energy carriers. Given that the nanoscale structural and chemical properties of solid interfaces can strongly influence this thermal boundary conductance, the ballistic and diffusive nature of phonon transport along with the corresponding phonon wavelengths can affect how energy is scattered and transmitted across an interfacial region between two materials. In hybrid composites composed of atomic layer building blocks of inorganic and organic constituents, the varying interaction between the phononic spectrum in the inorganic crystals and vibronic modes in the molecular films can provide a new avenue to manipulate the energy exchange between the fundamental vibrational energy carriers across interfaces. Here, we systematically study the heat transfer mechanisms in hybrid superlattices of atomic- and molecular-layer-grown zinc oxide and hydroquinone with varying thicknesses of the inorganic and organic layers in the superlattices. We demonstrate ballistic energy transfer of phonons in the zinc oxide that is limited by scattering at the zinc oxide/hydroquinone interface for superlattices with a single monolayer of hydroquinone separating the thicker inorganic layers. The concomitant thermal boundary conductance across the zinc oxide interfacial region approaches the maximal thermal boundary conductance of a zinc oxide phonon flux, indicative of the contribution of long wavelength vibrations across the aromatic molecular monolayers in transmitting energy across the interface. This transmission of energy across the molecular interface decreases considerably as the thickness of the organic layers are increased.

  4. Tuberculosis: An Inorganic Medicinal Chemistry Perspective.

    PubMed

    Viganor, Livia; Skerry, Ciaran; McCann, Malachy; Devereux, Michael

    2015-01-01

    Tuberculosis (TB) which is caused by the resilient pathogen Mycobacterium tuberculosis (MTB) has re-emerged to become a leading public health problem in the world. The growing number of multi-drug resistant MTB strains and the more recently emerging problem with the extensively drug resistant strains of the pathogen are greatly undermining conventional anti-TB therapeutic strategies which are lengthy and expose patients to toxicity and other unwanted side effects. The search for new anti-TB drugs essentially involves either the repurposing of existing organic drugs which are now off patent and already FDA approved, the synthesis of modified analogues of existing organic drugs, with the aim of shortening and improving drug treatment for the disease, or the search for novel structures that offer the possibility of new mechanisms of action against the mycobacterium. Inorganic medicinal chemistry offers an alternative to organic drugs through opportunities for the design of therapeutics that target different biochemical pathways. The incorporation of metal ions into the molecular structure of a potential drug offers the medicinal chemist an opportunity to exploit structural diversity, have access to various oxidation states of the metal and also offer the possibility of enhancing the activity of an established organic drug through its coordination to the metal centre. In this review, we summarize what is currently known about the antitubercular capability of metal complexes, their mechanisms of action and speculate on their potential applications in the clinic.

  5. Natural hybrid organic-inorganic photovoltaic devices

    NASA Astrophysics Data System (ADS)

    De Padova, Paola; Lucci, Massimiliano; Olivieri, Bruno; Quaresima, Claudio; Priori, Sandro; Francini, Roberto; Grilli, Antonio; Hricovini, Karol; Davoli, Ivan

    2009-06-01

    Natural hybrid organic-inorganic photovoltaic devices based on TiO 2 have been realized. Chlorophyll A (from anacystis nidulans algae), chlorophyll B (from spinach), carmic acid (from insect Coccus cacti L.), synthetic trans- β-carotene, natural fresh picked Morus nigra, and their mixtures have been used as an organic photo active layer to fabricate photovoltaic prototypes. In order to reduce the charge's interfacial recombination, different thicknesses (5-45 nm) of Si layers, subsequently oxidized in air, were inserted between the TiO 2 and chlorophyll B. Scanning electron microscopy of TiO 2 and Si/TiO 2 systems shows the coexistence at least of four classes of nanoparticles of 60, 100, 150 and 250 nm in size. Auger electron spectroscopy of the Si L 2,3V V transition demonstrates the presence of silica and SiO x suboxides. Photocurrent measurements versus radiation wavelength in the range 300-800 nm exhibit different peaks according to the absorption spectra of the organic molecules. All realized photovoltaic devices are suitable for solar light electric energy conversion. Those made of a blend of all organic molecules achieved higher current and voltage output. The Si/TiO 2-based devices containing chlorophyll B exhibited an enhanced photocurrent response with respect to those with TiO 2 only.

  6. Surface science aspects on inorganic biomaterials

    SciTech Connect

    Kasemo, B.; Lausmaa, J.

    1986-01-01

    The chemical interaction between a foreign inorganic material, such as an implant, and living tissue takes place at an interface whose width initially is only about 1 nm. The processes at the interface, such as corrosion, ion diffusion, denaturing of proteins, etc., will eventually widen the interface until, at best, a dynamic quasiequilibrium is established. Since the chemical role of the implant in its interaction with the host tissue is almost exclusively determined by its outermost atomic layers, the characterization of implants on this length scale is necessary for understanding and controlling implant-tissue interactions. In this review, it is shown that modern surface science offers a variety of surface characterization spectroscopies, surface preparation methods, and theoretical concepts that can be directly applied in studies of biocompatible materials and biocompatibility, with particular reference to metallic materials. The general properties of metal surfaces, of oxides on metals, and bonding of molecules to such surfaces are reviewed, as well as the most important chemical and transport processes at solid-liquid interfaces. Several examples are given of how the experimental methods described in the article can be used for a thorough characterization and controlled preparation of titanium (Ti) surfaces. 92 references.

  7. Tuberculosis: An Inorganic Medicinal Chemistry Perspective.

    PubMed

    Viganor, Livia; Skerry, Ciaran; McCann, Malachy; Devereux, Michael

    2015-01-01

    Tuberculosis (TB) which is caused by the resilient pathogen Mycobacterium tuberculosis (MTB) has re-emerged to become a leading public health problem in the world. The growing number of multi-drug resistant MTB strains and the more recently emerging problem with the extensively drug resistant strains of the pathogen are greatly undermining conventional anti-TB therapeutic strategies which are lengthy and expose patients to toxicity and other unwanted side effects. The search for new anti-TB drugs essentially involves either the repurposing of existing organic drugs which are now off patent and already FDA approved, the synthesis of modified analogues of existing organic drugs, with the aim of shortening and improving drug treatment for the disease, or the search for novel structures that offer the possibility of new mechanisms of action against the mycobacterium. Inorganic medicinal chemistry offers an alternative to organic drugs through opportunities for the design of therapeutics that target different biochemical pathways. The incorporation of metal ions into the molecular structure of a potential drug offers the medicinal chemist an opportunity to exploit structural diversity, have access to various oxidation states of the metal and also offer the possibility of enhancing the activity of an established organic drug through its coordination to the metal centre. In this review, we summarize what is currently known about the antitubercular capability of metal complexes, their mechanisms of action and speculate on their potential applications in the clinic. PMID:25850770

  8. Inorganic Chemistry Solutions to Semiconductor Nanocrystal Problems

    SciTech Connect

    Alvarado, Samuel R.; Guo, Yijun; Ruberu, T. Purnima A.; Tavasoli, Elham; Vela, Javier

    2014-03-15

    The optoelectronic and chemical properties of semiconductor nanocrystals heavily depend on their composition, size, shape and internal structure, surface functionality, etc. Available strategies to alter these properties through traditional colloidal syntheses and ligand exchange methods place a premium on specific reaction conditions and surfactant combinations. In this invited review, we apply a molecular-level understanding of chemical precursor reactivity to reliably control the morphology, composition and intimate architecture (core/shell vs. alloyed) of semiconductor nanocrystals. We also describe our work aimed at achieving highly selective, low-temperature photochemical methods for the synthesis of semiconductor–metal and semiconductor–metal oxide photocatalytic nanocomposites. In addition, we describe our work on surface modification of semiconductor nanocrystal quantum dots using new approaches and methods that bypass ligand exchange, retaining the nanocrystal's native ligands and original optical properties, as well as on spectroscopic methods of characterization useful in determining surface ligand organization and chemistry. Using recent examples from our group and collaborators, we demonstrate how these efforts have lead to faster, wider and more systematic application of semiconductor nanocrystal-based materials to biological imaging and tracking, and to photocatalysis of unconventional substrates. We believe techniques and methods borrowed from inorganic chemistry (including coordination, organometallic and solid state chemistry) have much to offer in reaching a better understanding of the synthesis, functionalization and real-life application of such exciting materials as semiconductor nanocrystals (quantum dots, rods, tetrapods, etc.).

  9. Design and synthesis of inorganic/organic hybrid electrochemical materials

    NASA Astrophysics Data System (ADS)

    Harreld, John H.

    An ambient pressure method for drying sol-gel materials is developed to synthesize high porosity (80--90%), high surface area vanadium oxide and silica aerogel materials (150--300 and 1000 m2/g for vanadium pentoxide and silica, respectively). The synthesis approach uses liquid exchange to replace the pore fluid with a low surface tension, nonpolar solvent which reduces the capillary pressures developed during drying. The Good-Girifalco interaction parameter is used to calculate pore stresses resulting from drying silica gels from various liquids. Vanadium oxide/polypyrrole hybrid aerogels are prepared using three strategies. These approaches focus on either sequential or consecutive polymerization of the inorganic and organic networks. Microcomposite aerogels are synthesized by encapsulating a dispersion of preformed polypyrrole in a vanadium pentoxide gel. In the second approach, pyrrole is polymerized and doped within the pore volume of preformed vanadium pentoxide gel. When the inorganic and organic precursors are polymerized simultaneously, the resulting gels exhibited a nanometer scaled microstructure with homogeneous distributions of either phases. Through this route, a suitable microstructure and composition for a lithium secondary battery cathode is obtained. Lithiated aerogels of hydrated nickel, cobalt, and mixed nickel-cobalt oxides are synthesized from lithium hydroxide and transition metal acetate precursors. The XRD analyses indicate that the nickel containing gels exhibit a lithium deficiency (less than 1 Li/transition metal. By increasing the concentration of the lithium precursor the lithium content in nickel oxides is increased, and additional base solution is no longer required to catalyze gelation. A non-hydrolytic sol-gel approach is utilized to create tin oxide and tin-aluminum binary oxide aerogels with high porosity (90%) and high surface area (300 m2/g). XRD data from single phase tin oxide aerogel indicates the growth of SnO2 crystallites

  10. Infrared Spectra of Simple Inorganic Ion Pairs in Solid Solution: A Physical Inorganic Chemistry Experiment.

    ERIC Educational Resources Information Center

    Miller, Philip J.; Tong, William G.

    1980-01-01

    Presents a physical inorganic experiment in which large single crystals of the alkali halides doped with divalent ion impurities are prepared easily. Demonstrates the ion pairing of inorganic ions in solid solution. (CS)

  11. Inorganic hollow nanotube aerogels by atomic layer deposition onto native nanocellulose templates.

    PubMed

    Korhonen, Juuso T; Hiekkataipale, Panu; Malm, Jari; Karppinen, Maarit; Ikkala, Olli; Ras, Robin H A

    2011-03-22

    Hollow nano-objects have raised interest in applications such as sensing, encapsulation, and drug-release. Here we report on a new class of porous materials, namely inorganic nanotube aerogels that, unlike other aerogels, have a framework consisting of inorganic hollow nanotubes. First we show a preparation method for titanium dioxide, zinc oxide, and aluminum oxide nanotube aerogels based on atomic layer deposition (ALD) on biological nanofibrillar aerogel templates, that is, nanofibrillated cellulose (NFC), also called microfibrillated cellulose (MFC) or nanocellulose. The aerogel templates are prepared from nanocellulose hydrogels either by freeze-drying in liquid nitrogen or liquid propane or by supercritical drying, and they consist of a highly porous percolating network of cellulose nanofibrils. They can be prepared as films on substrates or as freestanding objects. We show that, in contrast to freeze-drying, supercritical drying produces nanocellulose aerogels without major interfibrillar aggregation even in thick films. Uniform oxide layers are readily deposited by ALD onto the fibrils leading to organic-inorganic core-shell nanofibers. We further demonstrate that calcination at 450 °C removes the organic core leading to purely inorganic self-supporting aerogels consisting of hollow nanotubular networks. They can also be dispersed by grinding, for example, in ethanol to create a slurry of inorganic hollow nanotubes, which in turn can be deposited to form a porous film. Finally we demonstrate the use of a titanium dioxide nanotube network as a resistive humidity sensor with a fast response.

  12. The impact of wafering on organic and inorganic surface contaminations

    NASA Astrophysics Data System (ADS)

    Meyer, S.; Wahl, S.; Timmel, S.; Köpge, R.; Jang, B.-Y.

    2016-08-01

    Beside the silicon feedstock material, the crystallization process and the cell processing itself, the wafer sawing process can strongly determine the final solar cell quality. Especially surface contamination is introduced in this process step because impurities from sawing meet with a virgin silicon surface which is highly reactive until the oxide layer is formed. In this paper we quantitatively analysed both, the organic and inorganic contamination on wafer surfaces and show that changes of process parameters during wafering may cause dramatic changes in surface purity. We present powerful techniques for the monitoring of wafer surface quality which is essential for the production of high efficiency and high quality solar cells.

  13. In vivo degeneration and the fate of inorganic nanoparticles.

    PubMed

    Feliu, Neus; Docter, Dominic; Heine, Markus; Del Pino, Pablo; Ashraf, Sumaira; Kolosnjaj-Tabi, Jelena; Macchiarini, Paolo; Nielsen, Peter; Alloyeau, Damien; Gazeau, Florence; Stauber, Roland H; Parak, Wolfgang J

    2016-05-01

    What happens to inorganic nanoparticles (NPs), such as plasmonic gold or silver, superparamagnetic iron oxide, or fluorescent quantum dot NPs after they have been administrated to a living being? This review discusses the integrity, biodistribution, and fate of NPs after in vivo administration. The hybrid nature of the NPs is described, conceptually divided into the inorganic core, the engineered surface coating comprising of the ligand shell and optionally also bio-conjugates, and the corona of adsorbed biological molecules. Empirical evidence shows that all of these three compounds may degrade individually in vivo and can drastically modify the life cycle and biodistribution of the whole heterostructure. Thus, the NPs may be decomposed into different parts, whose biodistribution and fate would need to be analyzed individually. Multiple labeling and quantification strategies for such a purpose will be discussed. All reviewed data indicate that NPs in vivo should no longer be considered as homogeneous entities, but should be seen as inorganic/organic/biological nano-hybrids with complex and intricately linked distribution and degradation pathways. PMID:26862602

  14. Organic/Inorganic Complex Pigments: Ancient Colors Maya Blue

    SciTech Connect

    Polette-Niewold, L.A.; Manciu, F.S.; Torres, B.; Alvarado, M.; Jr.; Chianelli, R.R.

    2009-06-04

    Maya Blue is an ancient blue pigment composed of palygorskite clay and indigo. It was used by the ancient Maya and provides a dramatic background for some of the most impressive murals throughout Mesoamerica. Despite exposure to acids, alkalis, and chemical solvents, the color of the Maya Blue pigment remains unaltered. The chemical interaction between palygorskite and indigo form an organic/inorganic complex with the carbonyl oxygen of the indigo bound to a surface Al{sup 3+} in the Si-O lattice. In addition indigo will undergo an oxidation to dehydroindigo during preparation. The dehydro-indigo molecule forms a similar but stronger complex with the Al{sup 3+}. Thus, Maya Blue varies in color due to the mixed indigo/dehydroindigo complex. The above conclusions are the result of application of multiple techniques (X-ray diffraction, differential thermal analysis/thermal gravimetric analysis, high resolution transmission electron microscopy, scanning electron microscopy, infrared and Raman spectroscopy) to the characterization of the organic/inorganic complex. A picture of the bonding of the organic molecule to the palygorskite surface forming a surface complex is developed and supported by the results of density functional theory calculations. We also report that other organic molecules such as thioindigo form similar organic/inorganic complexes thus, opening an entirely new class of complex materials for future applications.

  15. Organic/inorganic complex pigments: ancient colors Maya Blue.

    PubMed

    Polette-Niewold, Lori Ann; Manciu, Felicia S; Torres, Brenda; Alvarado, Manuel; Chianelli, Russell R

    2007-11-01

    Maya Blue is an ancient blue pigment composed of palygorskite clay and indigo. It was used by the ancient Maya and provides a dramatic background for some of the most impressive murals throughout Mesoamerica. Despite exposure to acids, alkalis, and chemical solvents, the color of the Maya Blue pigment remains unaltered. The chemical interaction between palygorskite and indigo form an organic/inorganic complex with the carbonyl oxygen of the indigo bound to a surface Al(3+) in the Si-O lattice. In addition indigo will undergo an oxidation to dehydroindigo during preparation. The dehydro-indigo molecule forms a similar but stronger complex with the Al(3+). Thus, Maya Blue varies in color due to the mixed indigo/dehydroindigo complex. The above conclusions are the result of application of multiple techniques (X-ray diffraction, differential thermal analysis/thermal gravimetric analysis, high resolution transmission electron microscopy, scanning electron microscopy, infrared and Raman spectroscopy) to the characterization of the organic/inorganic complex. A picture of the bonding of the organic molecule to the palygorskite surface forming a surface complex is developed and supported by the results of density functional theory calculations. We also report that other organic molecules such as thioindigo form similar organic/inorganic complexes thus, opening an entirely new class of complex materials for future applications.

  16. Thermal and chemical degradation of inorganic membrane materials. Topical report

    SciTech Connect

    Krishnan, G.N.; Sanjurjo, A.; Wood, B.J.; Lau, K.H.

    1994-04-01

    This report describes the results of a literature review to evaluate the long-term thermal and chemical degradation of inorganic membranes that are being developed to separate gaseous products produced by the gasification or combustion of coal in fixed-, fluidized-, and entrained-bed gasifiers, direct coal-fired turbines, and pressurized-fluidized-bed combustors. Several impurities, such as H{sub 2}S, NH{sub 3}, SO{sub 2}, NO{sub x}, and trace metal compounds are generated during coal conversion, and they must be removed from the coal gas or the combustor flue gas to meet environmental standards. The use of membranes to separate these noxious gases is an attractive alternative to their removal by sorbents such as zinc titanate or calcium oxide. Inorganic membranes that have a high separation efficiency and exhibit both thermal and chemical stability would improve the economics of power generation from coal. The U.S. Department of Energy is supporting investigations to develop inorganic membranes for separating hydrogen from coal gas streams and noxious impurities from hot coal- and flue-gas streams. Membrane materials that have been investigated in the past include glass (silica), alumina, zirconia, carbon, and metals (Pd and Pt).

  17. Preliminary Ion Exchange Modeling for Removal of Cesium from Hanford Waste Using Hydrous Crystalline Silicotitanate Material

    SciTech Connect

    HAMM, LUTHER L.

    2004-07-27

    For the current pretreatment facility design of the River Protection Project (RPP) Waste Treatment Plant (WTP), the removal of cesium from low activity waste (LAW) is achieved by ion-exchange technology based on SuperLig(R) 644 resin. Due to recent concerns over potential radiological and chemical degradation of SuperLig(R) 644 resin and increased pressure drops observed during pilot-scale column studies, an increased interest in developing a potential backup ion-exchanger material has resulted. Ideally, a backup ion-exchanger material would replace the SuperLig(R) 644 resin and have no other major impacts on the pretreatment facility flowsheet. Such an ideal exchanger has not been identified to date. However, Crystalline Silicotitanate (CST) ion-exchanger materials have been studied for the removal of cesium from a variety of DOE wastes over the last decade. CST ion-exchanger materials demonstrate a high affinity for cesium under high alkalinity conditions and have been under investigation for cesium removal specifically at Hanford and SRS during the last six years. Since CST is an inorganic based material (with excellent properties in regard to chemical, radiological, and thermal stability) that is considered to be practically non-elutable (while SuperLig(R) 644 is an organic based elutable resin), the overall pretreatment facility flowsheet would be impacted in various ways. However, the CST material is still being considered as a potential backup ion-exchanger material. The performance of a proposed backup ion-exchange column using IONSIV IE-911 (CST in its engineered-form) material for the removal of cesium from Hanford high level radioactive alkaline waste is discussed. This report focuses attention on the ion-exchange aspects and addresses the loading phase of the process cycle.

  18. Inorganic dual-layer microporous supported membranes

    DOEpatents

    Brinker, C. Jeffrey; Tsai, Chung-Yi; Lu, Yungfeng

    2003-03-25

    The present invention provides for a dual-layer inorganic microporous membrane capable of molecular sieving, and methods for production of the membranes. The inorganic microporous supported membrane includes a porous substrate which supports a first inorganic porous membrane having an average pore size of less than about 25 .ANG. and a second inorganic porous membrane coating the first inorganic membrane having an average pore size of less than about 6 .ANG.. The dual-layered membrane is produced by contacting the porous substrate with a surfactant-template polymeric sol, resulting in a surfactant sol coated membrane support. The surfactant sol coated membrane support is dried, producing a surfactant-templated polymer-coated substrate which is calcined to produce an intermediate layer surfactant-templated membrane. The intermediate layer surfactant-templated membrane is then contacted with a second polymeric sol producing a polymeric sol coated substrate which is dried producing an inorganic polymeric coated substrate. The inorganic polymeric coated substrate is then calcined producing an inorganic dual-layered microporous supported membrane in accordance with the present invention.

  19. 29 CFR 1926.1118 - Inorganic arsenic.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 8 2011-07-01 2011-07-01 false Inorganic arsenic. 1926.1118 Section 1926.1118 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... Inorganic arsenic. Note: The requirements applicable to construction work under this section are...

  20. 29 CFR 1926.1118 - Inorganic arsenic.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 8 2012-07-01 2012-07-01 false Inorganic arsenic. 1926.1118 Section 1926.1118 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... Inorganic arsenic. Note: The requirements applicable to construction work under this section are...

  1. 29 CFR 1926.1118 - Inorganic arsenic.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 8 2014-07-01 2014-07-01 false Inorganic arsenic. 1926.1118 Section 1926.1118 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... Inorganic arsenic. Note: The requirements applicable to construction work under this section are...

  2. 29 CFR 1926.1118 - Inorganic arsenic.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 8 2013-07-01 2013-07-01 false Inorganic arsenic. 1926.1118 Section 1926.1118 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... Inorganic arsenic. Note: The requirements applicable to construction work under this section are...

  3. 29 CFR 1926.1118 - Inorganic arsenic.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Inorganic arsenic. 1926.1118 Section 1926.1118 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... Inorganic arsenic. Note: The requirements applicable to construction work under this section are...

  4. 29 CFR 1915.1018 - Inorganic arsenic.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 7 2013-07-01 2013-07-01 false Inorganic arsenic. 1915.1018 Section 1915.1018 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... § 1915.1018 Inorganic arsenic. Note: The requirements applicable to shipyard employment under...

  5. 29 CFR 1915.1018 - Inorganic arsenic.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 7 2011-07-01 2011-07-01 false Inorganic arsenic. 1915.1018 Section 1915.1018 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... § 1915.1018 Inorganic arsenic. Note: The requirements applicable to shipyard employment under...

  6. 29 CFR 1915.1018 - Inorganic arsenic.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Inorganic arsenic. 1915.1018 Section 1915.1018 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... § 1915.1018 Inorganic arsenic. Note: The requirements applicable to shipyard employment under...

  7. 29 CFR 1915.1018 - Inorganic arsenic.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 7 2014-07-01 2014-07-01 false Inorganic arsenic. 1915.1018 Section 1915.1018 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... § 1915.1018 Inorganic arsenic. Note: The requirements applicable to shipyard employment under...

  8. 29 CFR 1915.1018 - Inorganic arsenic.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 7 2012-07-01 2012-07-01 false Inorganic arsenic. 1915.1018 Section 1915.1018 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... § 1915.1018 Inorganic arsenic. Note: The requirements applicable to shipyard employment under...

  9. 46 CFR 153.1045 - Inorganic acids.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Inorganic acids. 153.1045 Section 153.1045 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SHIPS CARRYING... § 153.1045 Inorganic acids. When Table 1 refers to this section, the person in charge of cargo...

  10. 46 CFR 153.1045 - Inorganic acids.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Inorganic acids. 153.1045 Section 153.1045 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SHIPS CARRYING... § 153.1045 Inorganic acids. When Table 1 refers to this section, the person in charge of cargo...

  11. 46 CFR 153.1045 - Inorganic acids.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Inorganic acids. 153.1045 Section 153.1045 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SHIPS CARRYING... § 153.1045 Inorganic acids. When Table 1 refers to this section, the person in charge of cargo...

  12. 46 CFR 153.1045 - Inorganic acids.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Inorganic acids. 153.1045 Section 153.1045 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SHIPS CARRYING... § 153.1045 Inorganic acids. When Table 1 refers to this section, the person in charge of cargo...

  13. 46 CFR 153.1045 - Inorganic acids.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Inorganic acids. 153.1045 Section 153.1045 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SHIPS CARRYING... § 153.1045 Inorganic acids. When Table 1 refers to this section, the person in charge of cargo...

  14. SPE speciation of inorganic arsenic in rice followed by hydride-generation atomic fluorescence spectrometric quantification

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Due to high toxicity, inorganic arsenics (iAs) are the focus of monitoring effort worldwide. In this work, extraction was performed by microwave-assisted digestion in HCl-H2O2, during which AsIII was oxidized to AsV. AsV was separated from organoarsenic species using silica-based SAX cartridge and r...

  15. Manure and inorganic N affect trace gas emissions under semi-arid irrigated corn