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Sample records for hydrous oxide inorganic

  1. Adsorption of arsenite and selenite using an inorganic ion exchanger based on Fe-Mn hydrous oxide.

    PubMed

    Szlachta, Małgorzata; Gerda, Vasyl; Chubar, Natalia

    2012-01-01

    The adsorption behaviour and mechanism of As(III) and Se(IV) oxyanion uptake using a mixed inorganic adsorbent were studied. The novel adsorbent, based on Fe(III)-Mn(III) hydrous oxides and manganese(II) carbonate, was synthesised using a hydrothermal precipitation approach in the presence of urea. The inorganic ion exchanger exhibited a high selectivity and adsorptive capacity towards As(III) (up to 47.6 mg/g) and Se(IV) (up to 29.0 mg/g), even at low equilibrium concentration. Although pH effects were typical for anionic species (i.e., the adsorption decreased upon pH increase), Se(IV) was more sensitive to pH changes than As(III). The rates of adsorption of both oxyanions were high. Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) studies showed that the ion exchange adsorption of both anions took place via OH(-) groups, mainly from Fe(III) but also Mn(III) hydrous oxides. MnCO(3) did not contribute directly to As(III) and Se(IV) removal. A higher adsorptive capacity of the developed material towards As(III) was partly due to partial As(III) oxidation during adsorption. PMID:21968401

  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. PMID:24528281

  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. 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.

  8. 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.

  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. 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.

  11. 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.

  12. 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.

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

    DOEpatents

    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. Ferrous iron sorption by hydrous metal oxides.

    PubMed

    Nano, Genevieve Villaseñor; Strathmann, Timothy J

    2006-05-15

    Ferrous iron is critical to a number of biogeochemical processes that occur in heterogeneous aquatic environments, including the abiotic reductive transformation of subsurface contaminants. The sorption of Fe(II) to ubiquitous soil minerals, particularly iron-free mineral phases, is not well understood. Colloidal TiO2, gamma-AlOOH, and gamma-Al2O2 were used as model hydrous oxides to investigate Fe(II) sorption to iron-free mineral surfaces. Rapid Fe(II) sorption during the first few hours is followed by a much slower uptake process that continues for extended periods (at least 30 days). For equivalent solution conditions, the extent of Fe(II) sorption decreases in the order TiO2 >gamma-Al2O3 >gamma-AlOOH. Short-term equilibrium sorption data measured over a wide range of conditions (pH, ionic strength, Fe(II)-to-sorbent ratio) are well described by the diffuse double layer model. Fe(II) sorption to TiO2 is best described by a single-site model that considers formation of two surface complexes, SOFe+ and SOFeOH0. For gamma-AlOOH and gamma-Al2O3, sorption data are best described by a two-site model that considers formation of SOFe+ complexes at weak- and strong-binding surface sites. Accurate description of sorption data for higher Fe(II) concentrations at alkaline pH conditions requires the inclusion of a Fe(II) surface precipitation reaction in the model formulation. The presence of common groundwater constituents (calcium, sulfate, bicarbonate, or fulvic acid) had no significant effect on Fe(II) sorption. These results demonstrate that iron-free soil minerals can exert a significant influence on Fe(II) sorption and speciation in heterogeneous aquatic systems. PMID:16337955

  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 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.

  17. 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.

  18. Thorium(IV) hydrous oxide solubility

    SciTech Connect

    Ryan, J.L.; Rai, D.

    1987-12-02

    The results of a study of the solubility of amorphous, hydrous ThO/sub 2/ over the pH range 3.5 - 14.2 are reported. The solubility is high at pH 3.5 and decreases rapidly at pH 4.5. The chemical modes of solubility over various pH ranges are discussed. No conclusive evidence for any amphoteric behavior of Th(IV) is reported. 22 references, 1 figure.

  19. RATES OF HYDROUS FERRIC OXIDE CRYSTALLIZATION AND THE INFLUENCE ON COPRECIPITATED ARSENATE: JOURNAL ARTICLE

    EPA Science Inventory

    NRMRL-ADA-02101 Ford*, R. Rates of Hydrous Ferric Oxide Crystallization and the Influence on Coprecipitated Arsenate. Environmental Science & Technology 36 (11):2459-2463 (2002). EPA/600/J-02/240. Arsenate coprecipitated with hydrous fer...

  20. Hydrous metal oxide catalysts for oxidation of hydrocarbons

    SciTech Connect

    Miller, J.E.; Dosch, R.G.; McLaughlin, L.I.

    1993-07-01

    This report describes work performed at Sandia under a CRADA with Shell Development of Houston, Texas aimed at developing hydrous metal oxide (HMO) catalysts for oxidation of hydrocarbons. Autoxidation as well as selective oxidation of 1-octene was studied in the presence of HMO catalysts based on known oxidation catalysts. The desired reactions were the conversion of olefin to epoxides, alcohols, and ketones, HMOs seem to inhibit autoxidation reactions, perhaps by reacting with peroxides or radicals. Attempts to use HMOs and metal loaded HMOs as epoxidation catalysts were unsuccessful, although their utility for this reaction was not entirely ruled out. Likewise, alcohol formation from olefins in the presence of HMO catalysts was not achieved. However, this work led to the discovery that acidified HMOs can lead to carbocation reactions of hydrocarbons such as cracking. An HMO catalyst containing Rh and Cu that promotes the reaction of {alpha}-olefins with oxygen to form methyl ketones was identified. Although the activity of the catalyst is relatively low and isomerization reactions of the olefin simultaneously occur, results indicate that these problems may be addressed by eliminating mass transfer limitations. Other suggestions for improving the catalyst are also made. 57 refs.

  1. Ultrasound-enhanced copper removal by hydrous iron oxide adsorption

    SciTech Connect

    Campos, H.R.; Wheat, P.E.

    1996-12-31

    A model system to investigate ultrasound-enhanced removal of metallic ions from aqueous solution by hydrous ferric oxide (HFO) adsorption has been conducted. The experimental data indicate that ultrasonic treatment of pre-formed HFO flocs can lead to enhanced removal of metallic ions from aqueous solution and that the level of enhancement is strongly correlated with the solution pH. Ultrasonic treatment has been shown to be effective at lowering the final solution concentration of copper species in the pH range 7.5--9.5 at copper to iron molar concentration ratios of 10 and 30%.

  2. 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.

  3. 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.

  4. Effect of temperature annealing on capacitive and structural properties of hydrous ruthenium oxides

    NASA Astrophysics Data System (ADS)

    Fang, Wei-Chuan; Huang, Jin-Hua; Chen, Li-Chyong; Su, Yuh-Long Oliver; Chen, Kuei-Hsien

    The structure-property relationships of hydrous ruthenium oxides, fabricated by electro deposition on Ti foil, were investigated with different annealing conditions. The annealing temperature was found to play an important role in affecting the electrochemical performance of the annealed hydrous ruthenium oxides. The results indicate that annealing hydrous ruthenium oxide at its crystallization threshold temperature, ∼200 °C, may help to create suitable nanostructure in the oxide that supports the establishment of interpenetrating percolation paths for balanced electron and proton conduction, thereby improving the capacitive response of the oxide dramatically. This finding is useful for fabrication of electrodes with enhanced electrochemical performance for application in microsupercapacitor.

  5. 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.

  6. Experimental Methodology for Determining Optimum Process Parameters for Production of Hydrous Metal Oxides by Internal Gelation

    SciTech Connect

    Collins, J.L.

    2005-10-28

    The objective of this report is to describe a simple but very useful experimental methodology that was used to determine optimum process parameters for preparing several hydrous metal-oxide gel spheres by the internal gelation process. The method is inexpensive and very effective in collection of key gel-forming data that are needed to prepare the hydrous metal-oxide microspheres of the best quality for a number of elements.

  7. 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.

  8. 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.

  9. Incipient hydrous oxide species as inhibitors of reduction processes at noble metal electrode

    SciTech Connect

    Burke, L.D.; O'Sullivan, J.F.; O'Dwyer, K.J.; Scannell, R.A.; Ahern, M.J.G.; McCarthy, M.M. )

    1990-08-01

    Evidence is presented to illustrate the important role of hydrous oxide in noble metal electrocatalysis. It was demonstrated, for instance, that in the case of gold in acid the onset/termination potential, under potential sweep conditions, for hydrazine oxidation and persulfate or iodate reduction occurred at the end of the hydrous oxide reduction peak (recorded for a thick film growth grown by potential multicycling); there was also a maximum in the faradaic ac response for gold in acid in the same region. Both gold and platinum were investigated in acid and base electrolytes. In some cases a range of potential, rather than a discrete value, was found to be involved, different species react with (or are inhibited by) different types (or coverages) of these submonolayer species. In some, possibly electrocatalytically nondemanding, reduction reactions the hydrous oxide seemed to have little effect.

  10. 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...

  11. 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

  12. Spectroscopic probes of the structure of hydrous uranium oxide precursors to UO sub 2 ceramic fuel

    SciTech Connect

    Thompson, M.C.; King, C.M. ); King, R.B. . Dept. of Chemistry)

    1989-01-01

    Fourier Transform infrared spectroscopy, x-ray powder diffraction and thermal analysis show that one example of ammonium diuranate'' observed as an intermediate in the U(VI) sol-gel process is a layered hydrous uranium oxide with a proposed structural formula of (NH){sub 4}{sub 2}((UO{sub 2}){sub 8}O{sub 4}(OH){sub 10}){center dot}8H{sub 2}O, an ammonium ion intercalate. Examples of polyamine intercalation compounds hydrous uranium oxide are also given.

  13. 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. PMID:25325790

  14. 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.

  15. Inorganic halogen oxidizers

    NASA Astrophysics Data System (ADS)

    Christe, K. O.; Wilson, W. W.

    1994-09-01

    A research program was carried out in novel energetic materials. This program was highly successful and resulted in 28 major publications. Highlights of this effort include: the characterization of the XeF5(-) anion which is the first example of a pentagonal planar XY5 structure, completion of our work on a quantitative oxidizer strength scale, the synthesis and characterization of new compounds at the limits of coordination and oxidation, such as XeOF5(-), TeOF6(2-), IOF6(-), IF8(-), TeF8(2-), TeF7(-), and XeF7(+), the study of fluxionality and steric repulsion effects in hexa- and hepta- coordinated species, such as IF7, HPF5(-), HSF5, and IOF5, the controlled replacement of two fluorine ligands by one doubly bonded oxygen ligand, studies of the thermal instability of NF5 and the F3(-) anion, the characterization of the N2F(+) cation N(CH3)4N3, H2N3(+) cation and the SF4(-) and SOF4(-) radical anions, the synthesis and characterization of a new Os(+VIII) compound, OsF4O2, theoretical studies on ONOF and a new family of polynitrogen compounds, the synthesis and characterization of the novel PF4(-) anion and it hydrolysis products, and the electrophilic fluorination of CH4 with F(+) equivalent N2F(+) and NF4(+) salts.

  16. Destruction of 2,2`,3 - trichlorobiphenyl in aqueous solution by hydrous pyrolysis/oxidation (HPO)

    SciTech Connect

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

    1997-11-25

    Aqueous, low-temperature oxidation rates for the polychlorinated biphenyl (PCB) congener 2,2`,3-trichlorobiphenyl have been measured in aqueous phosphate-buffered solutions using Dickson-type reaction vessels. Concentrations of the target compounds were determined by gas chromatography and compound identification was verified by gas chromatography - mass spectrometry. The reaction temperatures ranged from 131 {degrees}C to 165{degrees}C and the activation energy for the destruction of 2,2`,3-trichlorobiphenyl was estimated to be 134 kJ/mole. In a low concentration experiment (approximately 500 ng/g starting concentration), 2,2`,3-trichlorobiphenyl concentration reached non-detect in two days at 135{degrees}C. In a much higher concentration experiment (approximately 24,000 mg/g initial loading), nearly 40% of the initial 2,2`,3-trichlorobiphenyl concentration, or about 10,000 ng/g was destroyed at 161{degrees}C in 18 days. The 2,2`, 3-trichlorobiphenyl concentration of 24,000 ng/g measured at 131{degrees}C represents a greater than 100 fold increase in the aqueous solubility compared to the value of 200 ng/g at 20{degrees}C reported by Mackay et al. During the experiments the reacted portion of the 2,2`, 3-trichlorobiphenyl was completely mineralized, as indicated by a stoichiometric production of inorganic carbon and chloride ion, and no intermediates amenable to gas chromatography were observed during the HPO experiments. These preliminary experiments indicate that hydrous pyrolysis/oxidation (HPO) may be a useful alternative method for remediating soil and groundwater contaminated with PCBs.

  17. 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.

  18. 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.

  19. An exploratory program for using hydrous metal oxide ion exchangers as Fischer-Tropsch catalysts

    SciTech Connect

    Lynch, A.W.; Dosch, R.G.; Sault, A.G.

    1990-01-01

    The purpose of this program is to investigate the potential of hydrous metal oxide (HMO) ion exchangers, invented at Sandia National Laboratories, as Fischer-Tropsch (F-T) catalysts. Metals known to be active in F-T synthesis (e.g. Fe, Co) were ion exchanged on hydrous metal oxide supports. Although HMO catalysts based on Zr, Nb, and Ta have been investigated in direct coal liquefaction studies, this effect focused on formulations based on the hydrous titanium oxide (HTO) system. The program has the goals of developing a catalyst with (1) high activity, (2) selectively to fuel range or other useful products, and (3) better properties for use in slurry reactors. The program has three main tasks: (1) catalyst synthesis, to develop methods for preparing catalysts having desirable F-T properties, (2) characterization, to investigate catalysts proving to have desirable properties by a variety of analytical techniques to determine correlations between activity and material properties and (3) testing to determine activity and selectivity of catalysts. This paper discussed results of activity testing of Ruhrchemie catalyst and some catalyst formulations prepared using ion exchange on hydrous titanium oxide and precipitation. For example, at 250{degree}C the Ruhrchemie catalyst converts {approximately}50% of the syngas feed to reaction products. In comparison, iron catalysts prepared by ion exchange and precipitation had conversions ranging from 20 to 50% over a temperature range of 250 to 275{degree}C of the syngas feed. In addition, results are Auger surface analysis of Ruhrchemie catalyst are presented. 6 refs., 2 figs., 2 tabs.

  20. 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.

  1. 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.

  2. 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.

  3. Spectroscopic probes of the structure of hydrous uranium oxide precursors to UO{sub 2} ceramic fuel

    SciTech Connect

    Thompson, M.C.; King, C.M.; King, R.B.

    1989-12-31

    Fourier Transform infrared spectroscopy, x-ray powder diffraction and thermal analysis show that one example of ``ammonium diuranate`` observed as an intermediate in the U(VI) sol-gel process is a layered hydrous uranium oxide with a proposed structural formula of (NH){sub 4}{sub 2}[(UO{sub 2}){sub 8}O{sub 4}(OH){sub 10}]{center_dot}8H{sub 2}O, an ammonium ion intercalate. Examples of polyamine intercalation compounds hydrous uranium oxide are also given.

  4. 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.

  5. Ianthinite: A rare hydrous uranium oxide mineral from Akkavaram, Andhra Pradesh, India

    NASA Astrophysics Data System (ADS)

    Singh, Yamuna; Viswanathan, R.; Parashar, K. K.; Srivastava, S. K.; Ramesh Babu, P. V.; Parihar, P. S.

    2014-02-01

    Ianthinite is the only known uranyl oxide hydrate mineral that contains both U6 + and U4 + . For the first time, we report ianthinite from India (at Akkavaram, Andhra Pradesh), which is hosted in basement granitoids. The mineral occurs in the form of tiny grains, encrustations and coatings in intimate association with uraninite and uranophane. X-ray diffraction (XRD) data reveals that d-spacings of the investigated ianthinite are in close agreement with the corresponding values given for ianthinite standard in International Centre for Diffraction Data (ICDD) card no. 12-272. The crystallographic parameters of the studied ianthinite are: ao = 11.3 (1) Å, bo = 7.19 (3) Å and co = 30.46 (8) Å, with a unit cell volume of 2474 (27) Å3. The association of investigated ianthinite with uraninite suggests that the former has formed due to oxidation of the latter. Since a major part of the uraninite was exposed to oxidizing meteoric water, much of it has been transformed into hydrous uranium oxide (ianthinite) and very little part remained unaltered as uranium oxide (uraninite). Absence of schoepite in the investigated ianthinite suggests that after its formation it (ianthinite) was not exposed to oxygen/oxidizing meteoric water. As the oxidation was partial and short lived, some amount of primary uraninite is also preserved.

  6. 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.

  7. 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

  8. Role of Surface Precipitation in Copper Sorption by the Hydrous Oxides of Iron and Aluminum.

    PubMed

    Karthikeyan; Elliott; Chorover

    1999-01-01

    Isotherms were developed at pH 6.9 for adsorption (ADS) and coprecipitation (CPT) of Cu by hydrous oxides of Fe (HFO) and Al (HAO) to study the role of sorbate/sorbent ratio in metal cation removal. For low sorbate/sorbent conditions, HFO had a higher Cu retention capacity than HAO regardless of contact methodology. For either oxide, CPT was consistently more effective than ADS in removing Cu from solution. At high sorbate/sorbent ratios, surface precipitation dominates and the oxide's net cation retention capacity depends on the nature and solubility of the precipitate formed at the oxide-water interface. X-ray diffraction patterns and isotherms of HAO for both ADS and CPT suggest formation of a solid solution [e.g., CuAl2O4(s)] with dramatically lower solubility than Cu(OH)2(s) precipitated in bulk solution. In contrast, Cu precipitated on the HFO surface exhibited a solubility comparable to the bulk precipitated Cu(OH)2(s). Therefore, at high sorbate/sorbent ratios, HAO has a higher Cu "apparent" sorption capacity than HFO. The relative utility of these oxides as metal scavengers thus depends markedly on sorbate/sorbent conditions. Copyright 1999 Academic Press. PMID:9878138

  9. 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

  10. 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

  11. 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

  12. Ni(II) complexation to amorphous hydrous ferric oxide: an X-ray absorption spectroscopy study.

    PubMed

    Xu, Ying; Axe, Lisa; Boonfueng, Thipnakarin; Tyson, Trevor A; Trivedi, Paras; Pandya, Kaumudi

    2007-10-01

    Ni(II) sorption onto iron oxides and in particular hydrous ferric oxide (HFO) is among the important processes impacting its distribution, mobility, and bioavailability in environment. To develop mechanistic models for Ni, extended X-ray absorption fine structure (EXAFS) analysis has been conducted on Ni(II) sorbed to HFO. Coprecipitation revealed the formation of the metastable alpha-Ni(OH)(2) at a Ni(II) loading of 3.5 x 10(-3) molg(-1). On the other hand, Ni(II) formed inner-sphere mononuclear bidentate complexes along edges of FeO(6) octahedra when sorbed to HFO surfaces with Ni-O distances of 2.05-2.07 A and Ni-Fe distances of 3.07-3.11 A. This surface complex was observed by EXAFS study over 2.8 x 10(-3) to 10(-1) ionic strength, pH from 6 to 7, a Ni(II) loading of 8 x 10(-4) to 8.1 x 10(-3) molg(-1) HFO, and reaction times from 4 hours to 8 months. The short- and long-range structure analyses suggest that the presence of Ni(II) inhibited transformation of the amorphous iron oxide into a more crystalline form. However, Ni(2+) was not observed to substitute for Fe(3+) in the oxide structure. This study systematically addresses Ni(II) adsorption mechanisms to amorphous iron oxide. The experimentally defined surface complexes can be used to constrain surface complexation modeling for improved prediction of metal distribution at the iron oxide/aqueous interface. PMID:17561066

  13. Ion dynamics in the pseudocapacitive reaction of hydrous ruthenium oxide. Effect of the temperature pre-treatment

    NASA Astrophysics Data System (ADS)

    Sopčić, Suzana; Mandić, Zoran; Inzelt, György; Roković, Marijana Kraljić; Meštrović, Ernest

    2011-05-01

    Pseudocapacitive redox reaction of hydrous ruthenium oxide was investigated by the combined electrochemical and quartz crystal nanobalance measurements on gold support in H2SO4 and Na2SO4 solutions. The results show that the pseudocapacitance arises from at least two different Faradaic reactions with significant influence of double layer capacitance. All three processes simultaneously take place during charging/discharging reaction, but their contribution vary depending on the electrolyte used, the temperature pre-treatment and on the potential range. One Faradaic reaction releases protons during oxidation reaction resulting in the electrode mass decrease, while another Faradaic reaction results in the chemical binding of water leading to the mass gain during the oxidation reaction. The former reaction is favoured in acidic electrolyte and at lower anodic potentials, and the latter reaction proceeds predominantly in neutral media and at higher anodic potentials. The influence of annealing temperatures on the characteristics of the redox reaction of hydrous ruthenium oxide, as well as on its capacitance, was confirmed. It was demonstrated that specific capacitances of hydrous ruthenium oxide could achieve values as high as 1500 F g-1, provided that conditions of good electronic conductivity among RuO2 particles, as well as good electrical contact between gold and RuO2, are met.

  14. Mediated electron transfer between Fe(II) adsorbed onto hydrous ferric oxide and a working electrode.

    PubMed

    Klein, Annaleise R; Silvester, Ewen; Hogan, Conor F

    2014-09-16

    The redox properties of Fe(II) adsorbed onto mineral surfaces have been highly studied over recent years due to the wide range of environmental contaminants that react with this species via abiotic processes. In this work the reactivity of Fe(II) adsorbed onto hydrous ferric oxide (HFO) has been studied using ferrocene (bis-cyclopentadienyl iron(II); Fc) derivatives as electron shuttles in cyclic voltammetry (CV) experiments. The observed amplification of the ferrocene oxidation peak in CV is attributed to reaction between the electrochemically generated ferrocenium (Fc(+)) ion and adsorbed Fe(II) species in a catalytic process (EC' mechanism). pH dependence studies show that the reaction rate increases with Fe(II) adsorption and is maintained in the absence of aqueous Fe(2+), providing strong evidence that the electron transfer process involves the adsorbed species. The rate of reaction between Fc(+) and adsorbed Fe(II) increases with the redox potential of the ferrocene derivative, as expected, with bimolecular rate constants in the range 10(3)-10(5) M(-1) s(-1). The ferrocene-mediated electrochemical method described has considerable promise in the development of a technique for measuring electron-transfer rates in geochemical and environmental systems. PMID:25157830

  15. Solubility data for U(VI) hydroxide and Np(IV) hydrous oxide: application of MCC-3 methodology

    SciTech Connect

    Krupka, K.M.; Rai, D.; Fulton, R.W.; Strickert, R.G.

    1984-10-01

    Experiments based on a modified MCC-3S test method were conducted to investigate the solubility of U(VI) hydroxide (the mineral schoepite) and Np(IV) hydrous oxide at ambient temperature. The solubility of U(VI) hydroxide was investigated in carbonate-free, oxidizing aqueous solutions in the pH range of 3 to 11. The measured concentrations of dissolved U confirm the amphoteric behavior of U(VI) hydroxide solid and the importance of anionic U(VI) hydroxyl complexes in accurately calculating the solubilities of U(VI) solids under basic pH conditions. the effect of fluoride complexation on the solubility of Np(IV) hydrous oxide was studied in carbonate-free, near-neutral to alkaline solutions that contained 100 ppM total F. For solutions in which sodium dithionite (Na/sub 2/S/sub 2/O/sub 4/) and metallic Fe were used as reducing agents, the addition of 100 ppM F had no measurable effect on the solubility of Np(IV) hydrous oxide.

  16. Solubility data for U(VI) hydroxide and Np(IV) hydrous oxide: application of MCC-3 methodology

    SciTech Connect

    Krupka, K.M.; Rai, D.; Fulton, R.W.; Strickert, R.G.

    1985-01-01

    Experiments based on a modified MCC-3S test method were conducted to investigate the solubility of U(VI) hydroxide (the mineral schoepite) and Np(IV) hydrous oxide at ambient temperature. The solubility of U(VI) hydroxide was investigated in carbonate-free, oxidizing aqueous solutions in the pH range of 3 to 11. The measured concentrations of dissolved U confirm the amphoteric behavior of U(VI) hydroxide solid and the importance of anionic U(VI) solids under basic pH conditions. The effect of fluoride complexation on the solubility of Np(IV) hydrous oxide was studied in carbonate-free, near-neutral to alkaline solutions that contained 100 ppm total F. For solutions in which sodium dithionite (Na2S2O4) and metallic Fe were used as reducing agents, the addition of 100 ppm F had no measurable effect on the solubility of Np(IV) hydrous oxide. 20 references, 1 figure.

  17. 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.

  18. 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

  19. 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.

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

    PubMed

    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

  1. Quartz and Hydrous Iron Oxides from the Bee Bluff Structure of South Texas

    NASA Astrophysics Data System (ADS)

    Graham, R. A.; Martin, M.; Thadhani, N. N.; Morosin, B.

    2006-07-01

    There is substantial information showing that the Bee Bluff structure is an impact site and that a residual crater can be identified. The thin hard cap of Carrizo Sandstone, Indio fm calcareous silt and a thin layer of iron-rich siltstone leads to impact processes in which the high pressure release wave proceeds promptly upward leading to a trapping of metamorphic products at the impact interface, a `bottom-up' pressure release. Release of water from goethite binder in the sandstone and from the iron-rich siltstone results in supersaturated steam in mixtures with iron and quartz compounds. Samples with quartz and hydrous iron oxide features are examined with optical microscopy, SEM, EDX and XRD. A quartz grain is found with a well defined PDF set. There is widespread amorphous quartz including lechatleriete. Nanocrystals of α-goethite in the acicular form are common. A condensation sphere from the `Uvalde Crater Rosetta Stone' shows a complex mixture of hematite, goethite, and alpha quartz with a trace of trydimite. Numerous samples are yet to be analyzed. The crater appears to have features that can serve as an Earth analog to Mars craters. A companion paper in the present proceedings summarizes prior work, adds new site detail, reports impact-loading analysis, and describes overall features of impactite samples from the site.

  2. 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

  3. 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.

  4. 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.

  5. 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

  6. 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

  7. Removal of arsenate with hydrous ferric oxide coprecipitation: effect of humic acid.

    PubMed

    Du, Jingjing; Jing, Chuanyong; Duan, Jinming; Zhang, Yongli; Hu, Shan

    2014-02-01

    Insights from the adverse effect of humic acid (HA) on arsenate removal with hydrous ferric oxide (HFO) coprecipitation can further our understanding of the fate of As(V) in water treatment process. The motivation of our study is to explore the competitive adsorption mechanisms of humic acid and As(V) on HFO on the molecular scale. Multiple complementary techniques were used including macroscopic adsorption experiments, surface enhanced Raman scattering (SERS), extended X-ray absorption fine structure (EXAFS) spectroscopy, flow-cell attenuated total reflectance Fourier transform infrared (ATR-FTIR) measurement, and charge distribution multisite complexation (CD-MUSIC) modeling. The As(V) removal efficiency was reduced from over 95% to about 10% with the increasing HA concentration to 25 times of As(V) mass concentration. The SERS analysis excluded the HA-As(V) complex formation. The EXAFS results indicate that As(V) formed bidentate binuclear surface complexes in the presence of HA as evidenced by an As-Fe distance of 3.26-3.31 angstroms. The in situ ATR-FTIR measurements show that As(V) replaces surface hydroxyl groups and forms innersphere complex. High concentrations of HA may physically block the surface sites and inhibit the As(V) access. The adsorption of As(V) and HA decreased the point of zero charge of HFO from 7.8 to 5.8 and 6.3, respectively. The CD-MUSIC model described the zeta potential curves and adsorption edges of As(V) and HA reasonably well. PMID:25076514

  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. 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

  10. 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.

  11. The solubility of Th(IV) hydrous oxide in concentrated NaCl and MgCl[sub 2] solutions

    SciTech Connect

    Sterner, S.M.; Felmy, A.R. ); Novak, C.F. )

    1995-09-01

    The solubility of Th(IV) hydrous oxide was studied in concentrated 4m and 6m NaCl solutions as well as in MgCl[sub 2] solutions ranging in concentration from 1m to 3m over a broad range of hydrogen ion concentrations. The observed solubilities in all solutions showed the same trend as observed previously of higher solubilities at early equilibration times, usually 7 to 8 days, followed by decreases in solubility with time as the precipitates aged. The trend of decreasing solubility with time was more pronounced in NaCl solutions than in MgCl[sub 2] solutions. The observed ThO[sub 2](am) solubilities in concentrated NaCl solutions (i.e., 4m and 6m) were lower than previously reported solubilities in more dilute NaCl solutions (i.e., < 3M NaCl). The results in MgCl[sub 2] were similar in all solutions regardless of the MgCl[sub 2] concentration. Current thermodynamic models for the solubility of hydrous thorium, oxide in chloride solutions, which primarily describe only aqueous Th[sup 4+]-Cl[sup -] ion-interactions, predicted higher solubilities than observed in 4 and 6m NaCl as well as in all MgCl[sub 2] solutions. An improved aqueous thermodynamic model, which includes ion-interaction parameters for like charged species, is proposed to explain these results.

  12. Preparation and characterization of composite electrodes of coconut-shell-based activated carbon and hydrous ruthenium oxide for supercapacitors

    NASA Astrophysics Data System (ADS)

    Dandekar, Mukta S.; Arabale, Girish; Vijayamohanan, K.

    The relationship between the structure-specific capacitance (F g -1) of a composite electrode consisting of activated coconut-shell carbon and hydrous ruthenium oxide (RuO x(OH) y) has been evaluated by impregnating various amounts of RuO x(OH) y into activated carbon that is specially prepared with optimum pore-size distribution. The composite electrode shows an enhanced specific capacitance of 250 F g -1 in 1 M H 2SO 4 with 9 wt.% ruthenium incorporated. Chemical and structural characterization of the composites reveals a homogeneous distribution of amorphous RuO x(OH) y throughout the porous network of the activated carbon. Electrochemical characterization indicates an almost linear dependence of capacitance on the amount of ruthenium owing to its pseudocapacitive nature.

  13. 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.

  14. Reconciling data on the iron oxidation state of anhydrous and hydrous aluminosilicate glasses and melts: a polymeric approach.

    NASA Astrophysics Data System (ADS)

    Moretti, R.

    2003-04-01

    The oxidation state of iron has been the object of attentive investigations during the last four decades. A first class of investigation involves glasses synthesized under nominally anhydrous conditions at atmospheric pressure: interpretation of iron oxidation state Vs. composition has given rise to some contradictions in literature about the structural role played by this element in silicate melts. Controversies are particularly relevant in the case of divalent iron, as testified by many spectroscopic determinations. The second class of investigation concerns hydrous aluminosilicate glasses synthesized under different T-P conditions. Again, no unique redox pattern has been found so far in literature, the ferric to ferrous iron ratio depending in a complex fashion on composition, temperature, pressure and oxygen fugacity of synthesis. The present study aims at showing that it is possible to reconcile such data by accounting for the acid-base properties of studied melts/glasses in the framework of a polymeric approach based on the concept of optical basicity and considering water speciation. Useful insights may thus be given about the dissociation equilibria of water in aluminosilicate melts/glasses. It is concluded that the developed model may be usefully employed for studying the evolution of the oxidation state of degassing and erupting silicate melts, showing that redox variations may be more reasonably ascribed to the melt compositional control rather than to changes in oxygen fugacity during magma migration from depth to surface.

  15. 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. PMID:23500428

  16. 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. PMID:20039732

  17. Novel approach to zinc removal from circum-neutral mine waters using pelletised recovered hydrous ferric oxide.

    PubMed

    Mayes, William M; Potter, Hugh A B; Jarvis, Adam P

    2009-02-15

    Data are presented which evaluate the performance of a pilot-scale treatment system using pelletised hydrous ferric oxide (HFO; a waste stream from coal mine water treatment) as a high surface area sorbent for removing zinc (Zn) from a metal mine water discharge in the North Pennines Orefield, UK. Over a 10-month period the system removed Zn at mean area- and volume-adjusted removal rates of 3.7 and 8.1gm(-3)day(-1), respectively, with a mean treatment efficiency of 32% at a low mean residence time of 49min. There were seasonal effects in Zn removal owing to establishment and dieback of algae in the treatment tank. This led to increased Zn uptake in early summer months followed by slight Zn release upon algae senescence. In addition to these biosorptive processes, the principal sinks for Zn appear to be (1) sorption onto the HFO surface, and (2) precipitation with calcite-dominated secondary minerals. The latter were formed as a product of dissolution of portlandite in the cement binder and calcium recarbonation. Further optimisation of the HFO pelletisation process holds the possibility for providing a low-cost, low footprint treatment option for metal rich mine waters, in addition to a valuable after-use for recovered HFO from coal mine water treatment facilities. PMID:18583040

  18. 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

  19. The formation, structure, and ageing of As-rich hydrous ferric oxide at the abandoned Sb deposit Pezinok (Slovakia)

    NASA Astrophysics Data System (ADS)

    Majzlan, Juraj; Lalinská, Bronislava; Chovan, Martin; Jurkovič, L.'ubomír; Milovská, Stanislava; Göttlicher, Jörg

    2007-09-01

    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 ˜380,000 m 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 2; arsenopyrite, FeAsS; berthierite, FeSb 2S 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 μ-XANES experiments indicate that As in the weathering rims is fully oxidized (As 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 2O 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 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 3.3-3.5 Å, that is, increasing polymerization of the iron

  20. 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

  1. Arsenate Adsorption by Hydrous Ferric Oxide Nanoparticles Embedded in Cross-linked Anion Exchanger: Effect of the Host Pore Structure.

    PubMed

    Li, Hongchao; Shan, Chao; Zhang, Yanyang; Cai, Jianguo; Zhang, Weiming; Pan, Bingcai

    2016-02-10

    Three composite adsorbents were fabricated via confined growth of hydrous ferric oxide (HFO) nanoparticles within cross-linked anion exchangers (NS) of different pore size distributions to investigate the effect of host pore structure on the adsorption of As(V). With the decrease in the average pore size of the NS hosts from 38.7 to 9.2 nm, the mean diameter of the confined HFO nanoparticles was lessened from 31.4 to 11.6 nm as observed by transmission electron microscopy (TEM), while the density of active surface sites was increased due to size-dependent effect proved by potentiometric titration. The adsorption capacity of As(V) yielded by Sips model was elevated from 24.2 to 31.6 mg/g via tailoring the pore size of the NS hosts, and the adsorption kinetics was slightly accelerated with the decrease of pore size in background solution containing 500 mg/L of Cl(-). Furthermore, the enhanced adsorption of As(V) was achieved over a wide pH range from 3 to 10, as well as in the presence of competing anions including Cl(-), SO4(2-), HCO3(-), NO3(-) (up to 800 mg/L), and PO4(3-) (up to 10 mg P/L). In addition, the fixed-bed working capacity increased from 2200 to 2950 bed volumes (BV) owing to the size confinement effect, which did not have adverse effect on the desorption of As(V) as the cumulative desorption efficiency reached 94% with 10 BV of binary solution (5% NaOH + 5% NaCl) for all the three adsorbents. Therefore, this study provided a promising strategy to regulate the reactivity of the nanoparticles via the size confinement effect of the host pore structure. PMID:26765396

  2. Breakdown of hydrous ringwoodite to pyroxene and spinelloid at high P and T and oxidizing conditions

    NASA Astrophysics Data System (ADS)

    Koch-Müller, M.; Rhede, D.; Schulz, R.; Wirth, R.

    2009-06-01

    3+ bearing phase at P-T conditions of the transition zone but because of the oxidizing conditions and the Fe-rich bulk composition needed one would expect it more in subduction zone environments than in the transition zone in senso stricto.

  3. 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

  4. Fundamental study on the solidification of Cs{sup +} and Sr{sup 2+} with hydrous Ti{sup IV} oxide modified with Si and Zr

    SciTech Connect

    Inoue, Y.; Yamazaki, H.; Erza, R.

    1993-12-31

    Fundamental data are provided for the potential use of hydrous Ti{sup IV}-Si oxide (TS) and hydrous Ti{sup IV}-Zr oxide (TZ) as the solidification media of radioactive Cs{sup +} and Sr{sup 2+}. The sorption capacity for Cs{sup +} and Sr{sup 2+}, at various conditions, and the structure and the composition of the exchangers in these ionic forms, at high temperature, were investigated, followed by measuring the leaching rate from the calcined exchangers into water at room temperature. TS uptakes more Cs{sup +} and Sr{sup +} than Tz does. The leaching rate from calcined TS is much lower than that from calcined TZ, due to the formation of titanium silicates of Cs{sup +} or Sr{sup 2+}. Based on these results, TS is considered to be superior to TZ, in sorption capacity, and the fixation capability of Cs{sup +} and Sr{sup 2+}, on the exchanger matrix.

  5. 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

  6. The solubility of Th(IV) and U(IV) hydrous oxides in concentrated NaHCO{sub 3} and Na{sub 2}CO{sub 3} solutions

    SciTech Connect

    Rai, D.; Felmy, A.R.; Moore, D.A.; Mason, M.J.

    1995-12-31

    The solubility of Th(IV) and U(IV) hydrous oxide was studied in the aqueous HCO{sub 3}{sup {minus}}-CO{sub 3}{sup 2{minus}}-OH{sup {minus}}-H{sub 2}O system extending to high concentration. The solubility of the Th(IV) and U(IV) hydrous oxides increases dramatically in both high bicarbonate and carbonate solutions and decreases with the increase in hydroxide at a fixed carbonate concentration. In general, the observed solubility of Th(IV) hydrous oxide at a given total carbonate concentration was three to four of magnitude higher than the solubility of U(IV) hydrous oxide. In the studies of the U(IV) system, extreme caution was used to ensure that the dissolved U was present as U(IV). Oxidation state analyses and systematic trends in the U(IV) solubility data similar to those for Th(IV), which is not redox sensitive, indicated that the dissolved U was present as U(IV).

  7. 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.

  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 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.

  11. Trace Metal Contamination in Sediments from U.K. Estuaries: An Empirical Evaluation of the Role of Hydrous Iron and Manganese Oxides

    NASA Astrophysics Data System (ADS)

    Turner, A.

    2000-03-01

    Concentrations of reducible trace metals (available to hydroxylamine hydrochloride-acetic acid; HA) have been determined in sediments from contrasting estuaries around the United Kingdom; specifically, estuaries receiving contemporary anthropogenic inputs from catchments which are urbanized and industrialized to varying degrees (Clyde, Dee, Forth, Loughor, Mersey and Poole Harbour), and estuaries receiving inputs from mineralized catchments where working of sulphidic ore deposits was important in the past (Fal, Hayle, Helford and Tavy). Mean estuarine ratios of Fe:Mn ranged from less than 10 (Dee, Mersey, Loughor) to about 100 (Fal, Poole Harbour); inter-estuarine variations in the mass contributions of Fe and Mn were attributed to differences in geological and hydrological catchment characteristics, while intra-estuarine variations were attributed to local differences in hydraulic sorting of sediment and redox conditions. The relative contributions of hydrous Fe and Mn oxides to the accumulation of trace metals (Cr, Cu, Pb, Zn) was evaluated by applying different regression analyses to each estuarine dataset. Overall, the most significant correlations were with Fe, and in estuaries draining mineralized catchments where well-defined contaminant metal sources exist; poor correlations in other cases were related to the dissolution of additional metal-bearing phases, including carbonates, by the digest (Dee, Loughor), or the inability of low energy environments (Clyde, Poole Harbour) to buffer the impacts of local sources of contaminant metals. Mean estuarine concentrations of Pb and Zn ranged from about 25 μg g -1(Poole Harbour) to 200 μg g -1(Hayle), and 80 μg g -1(Forth) to 1500 μg g -1(Hayle), respectively. Pooled Pb and Zn data were defined by a single regression equation which was not controlled by the availability or abundance of oxidic material, suggesting common environmental and anthropogenic sources and similar sorptive and post-depositional behaviours

  12. 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.

  13. Dietary Uptake of Cu Sorbed to Hydrous Iron Oxide is Linked to Cellular Toxicity and Feeding Inhibition in a Benthic Grazer.

    PubMed

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

    2016-02-01

    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 10(4) 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. PMID:26698541

  14. Protein-mediated adhesion of the dissimilatory Fe(III)-reducing bacterium Shewanella alga BrY to hydrous ferric oxide

    SciTech Connect

    Caccavo, F. Jr.

    1999-11-01

    The rate and extent of bacterial Fe(III) mineral reduction are governed by molecular-scale interactions between the bacterial cell surface and the mineral surface. These interactions are poorly understood. This study examined the role of surface proteins in the adhesion of Shewanella alga BrY to hydrous ferric oxide (HFO). Enzymatic degradation of cell surface polysaccharides had no effect on cell adhesion to HFO. The proteolytic enzymes Streptomyces griseus protease and chymotrypsin inhibited the adhesion of S. alga BrY cells to HFO through catalytic degradation of surface proteins. Trypsin inhibited S. alga BrY adhesion solely through surface-coating effects. Protease and chymotrypsin also mediated desorption of adhered S. alga BrY cells from HFO while trypsin did not mediate cell desorption. Protease removed a single peptide band that represented a protein with an apparent molecular mass of 50 kDa. Chymotrypsin removed two peptide bands that represented proteins with apparent molecular masses of 60 and 31 kDa. These proteins represent putative HGO adhesion molecules. A. alga BrY adhesion was inhibited by up to 46% when cells were cultured at sub-MICs of chloramphenicol, suggesting that protein synthesis is necessary for adhesion. Proteins extracted from the surface of S. alga BrY cells inhibited adhesion to HFO by up to 41%. A number of these proteins bound specifically to HFO, suggesting that a complex system of surface proteins mediates S. alga BrY adhesion to HFO.

  15. 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.

  16. Stability of amorphous hydrous manganese oxide in contrasting soils and implications for its use in chemical stabilization of metals/metalloids in contaminated soil environments

    NASA Astrophysics Data System (ADS)

    Ettler, V.; Knytl, V.; Komarek, M.; Della Puppa, L.; Mihaljevic, M.; Sebek, O.

    2012-04-01

    Amorphous manganese oxides are known to be efficient sorbents in soils and thus useful in remediation technologies. A novel amorphous hydrous manganese oxide (HMO) was prepared by a modified procedure generally used for birnessite synthesis. Its long-term stability in view of possible applications for chemical stabilization of metals/metalloids in polluted soils was evaluated. HMO was sealed in experimental bags prepared from polyamide fabric (pore size 1 um) and placed in the pots containing 200 g of soil. Three contrasting soils were used (two cambisols with pH values of 4.2 and 5.4, respectively, and a chernozem with a pH of 7.3). Each pot was equipped with a rhizon pore water sampler and the water content was maintained at 80% WHC throughout the experiment. HMO and pore waters were sampled after 1, 7, 15, 30, 45, 60, 75 and 90 days of incubation. Up to 113 mg Mn/L was released into pore water at the beginning of the experiment in more acidic soils indicating a slight dissolution of HMO surfaces. Manganese release into the pore water stabilized after 15 days in agreement with mass loss measurements. Mass loss decreased again after 60 days of the incubation for the neutral soil due to the formation of secondary rhodochrosite (MnCO3) detected on the HMO surfaces by X-ray diffraction analysis (XRD) and transmission electron microscopy (TEM). The efficiency of HMO for trace metal retention in soils (e.g., Zn) slightly decreased after 60 days, probably due to the mineralogical transformation of the sorbent leading to decrease of binding surfaces. Nevertheless, only approximately 10% of HMO dissolved after 90 days of experiment showing that this sorbent can be relatively stable in the studied soils. Its binding capacity for metals/metalloids should be further tested in soils with elevated contaminant concentrations.

  17. Selective mineralization of microbes in Fe-rich precipitates (jarosite, hydrous ferric oxides) from acid hot springs in the Waiotapu geothermal area, North Island, New Zealand

    NASA Astrophysics Data System (ADS)

    Jones, Brian; Renaut, Robin W.

    2007-01-01

    A group of small springs that are informally called "Orange Spring", located near Hakereteke Stream in the northern part of the Waiotapu geothermal area, feed hot (˜ 80 °C), acidic (pH: 2.1 - 2.4), As-rich sulfate waters into a discharge channel that is up to 25 cm deep. Submerged reddish-brown precipitates on the channel floor are formed largely of noncrystalline As-rich hydrous ferric oxide (HFO: mainly goethite), poorly crystalline lepidocrocite, and crystalline jarosite. Well-preserved coccoid and rod-shaped microbes are found in the As-rich HFO, but not in the lepidocrocite or jarosite. The jarosite was probably precipitated when the water had a low pH (< 3) and high SO 4 content, whereas the goethite and lepidocrocite were probably precipitated when the water had a slightly higher pH (> 4) and lower SO 4 content. The fluctuations in the pH and SO 4 content, which led to precipitation of the different mineral phases, may reflect mixing of the spring water with stream water that flowed through the channel when Hakereteke Stream was in flood stage. The goethite probably formed when coccoid and rod-shaped bacteria ( Acidithiobacillus ferrooxidans?) mediated rapid oxidization of the Fe 2+ to Fe 3+ that was then immediately coprecipitated with the As. Such rapid precipitation promoted mineralization of the microbes. The lack of mineralized microbes and the lower As in the lepidocrocite and jarosite may reflect precipitation rates that were slower than the decay rates of the microbes, or ecological factors that limited their growth.

  18. Dynamics of oxidation of inorganic sulphur compounds in upper soil horizons of spruce forests.

    PubMed

    Lettl, A; Langkramer, O; Lochman, V

    1981-01-01

    Dynamics of oxidation of inorganic sulphur compounds to sulphate by the soil of spruce forests was investigated. Sulphide, sulphite and thiosulphate are oxidized to sulphate at a maximal rate at the beginning of the reaction, oxidation of elemental sulphur exhibits a lag phase. Linear relationships between the amounts of the produced sulphate and concentrations of substrates in the soil could be detected. On the basis of ;this finding a method for comparison of the oxidative activity of various soils was proposed. PMID:7203284

  19. [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

  20. Combined Hydrous Ferric Oxide and Quaternary Ammonium Surfactant Tailoring of Granular Activated Carbon for Concurrent Arsenate and Perchlorate Removal

    SciTech Connect

    Jang, M.; Cannon, F; Parette, R; Yoon, S; Chen, W

    2009-01-01

    Activated carbon was tailored with both iron and quaternary ammonium surfactants so as to concurrently remove both arsenate and perchlorate from groundwater. The iron (hydr)oxide preferentially removed the arsenate oxyanion but not perchlorate; while the quaternary ammonium preferentially removed the perchlorate oxyanion, but not the arsenate. The co-sorption of two anionic oxyanions via distinct mechanisms has yielded intriguing phenomena. Rapid small-scale column tests (RSSCTs) with these dually prepared media employed synthetic waters that were concurrently spiked with arsenate and perchlorate; and these trial results showed that the quaternary ammonium surfactants enhanced arsenate removal bed life by 25-50% when compared to activated carbon media that had been preloaded merely with iron (hydr)oxide; and the surfactant also enhanced the diffusion rate of arsenate per the Donnan effect. The authors also employed natural groundwater from Rutland, MA which contained 60 microg/L As and traces of silica, and sulfate; and the authors spiked this with 40 microg/L perchlorate. When processing this water, activated carbon that had been tailored with iron and cationic surfactant could treat 12,500 bed volumes before 10 microg/L arsenic breakthrough, and 4500 bed volumes before 6 microg/L perchlorate breakthrough. Although the quaternary ammonium surfactants exhibited only a slight capacity for removing arsenate, these surfactants did facilitate a more favorably positively charged avenue for the arsenate to diffuse through the media to the iron sorption site (i.e. via the Donnan effect).

  1. 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

  2. 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

  3. 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.

  4. 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.

  5. 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

  6. Interactions of humic acid with nanosized inorganic oxides.

    PubMed

    Yang, Kun; Lin, Daohui; Xing, Baoshan

    2009-04-01

    Adsorption of natural organic matter (NOM) on nanoparticles (NPs) is important for evaluating their transport, transfer, and fate in the environment, which will also affect sorption of hydrophobic organic compounds (HOCs) by NPs and thereby potentially alter the toxicity of NPs and the fate, transport, and bioavailability of HOCs in the environment. Therefore, the adsorption behavior of humic acids (HA) by four types of nano-oxides (i.e., TiO2, SiO2, Al2O3, and ZnO) was examined in this study to explore their interaction mechanisms using techniques including Fourier transform infrared (FTIR) spectroscopy and elemental, zeta potential, and surface area analyses. Adsorption of HA was observed on nanosized TiO2, Al2O3, and ZnO but not on nano-SiO2. Furthermore, HA adsorption was pH-dependent. HA adsorption by nano-oxides was mainly induced by electrostatic attraction and ligand exchange between HA and nano-oxide surfaces. Surface hydrophilicity and negative charges of nano-oxides affected their adsorption of HA. However, the maxima of HA adsorption on nano-oxides were limited by the surface area of nano-oxides. HA phenolic OH and COOH groups were responsible for its ligand exchange with nano-TiO2 and nano-ZnO, respectively, while either HA COOH or HA phenolic/aliphatic OH was responsible for its ligand exchange with nano-Al2O3. HA adsorption decreased the micropore surface area of nano-oxides but not the external surface area because of the micropore blockage. HA adsorption also decreased the zeta potential of nano-oxides, indicating that HA-coated nano-oxides could be more easily dispersed and suspended and more stable in solution than uncoated ones because of their enhanced electrostatic repulsion. PMID:19708146

  7. 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.

  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. 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

  10. 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.

  11. 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

  12. 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

  13. The crystal chemistry of inorganic metal borohydrides and their relation to metal oxides.

    PubMed

    Černý, Radovan; Schouwink, Pascal

    2015-12-01

    The crystal structures of inorganic homoleptic metal borohydrides are analysed with respect to their structural prototypes found amongst metal oxides in the inorganic databases such as Pearson's Crystal Data [Villars & Cenzual (2015). Pearson's Crystal Data. Crystal Structure Database for Inorganic Compounds, Release 2014/2015, ASM International, Materials Park, Ohio, USA]. The coordination polyhedra around the cations and the borohydride anion are determined, and constitute the basis of the structural systematics underlying metal borohydride chemistry in various frameworks and variants of ionic packing, including complex anions and the packing of neutral molecules in the crystal. Underlying nets are determined by topology analysis using the program TOPOS [Blatov (2006). IUCr CompComm. Newsl. 7, 4-38]. It is found that the Pauling rules for ionic crystals apply to all non-molecular borohydride crystal structures, and that the latter can often be derived by simple deformation of the close-packed anionic lattices c.c.p. and h.c.p., by partially removing anions and filling tetrahedral or octahedral sites. The deviation from an ideal close packing is facilitated in metal borohydrides with respect to the oxide due to geometrical and electronic considerations of the BH4(-) anion (tetrahedral shape, polarizability). This review on crystal chemistry of borohydrides and their similarity to oxides is a contribution which should serve materials engineers as a roadmap to design new materials, synthetic chemists in their search for promising compounds to be prepared, and materials scientists in understanding the properties of novel materials. PMID:26634719

  14. Oxidative properties and chemical stability of fluoronanotubes in matrixes of binary inorganic compounds.

    PubMed

    Peng, Haiqing; Gu, Zhenning; Liu, Yu; Chiang, Ivana W; Smalley, Richard E; Hauge, Robert H; Khabashesku, Valery N; Margrave, John L

    2003-01-01

    The chemical stability of fluoronanotubes in selected solid inorganic matrixes has been studied by initially mixing and mechanically grinding the components and subsequently heating them at temperatures ranging from 35 to 600 degrees C. The inorganic compounds selected for matrixes included halides (KBr, KI, Lil, LiBr, LiCl, NaCl, Znl2), oxides (Li2O, Fe2O3, PbO, MnO), lithium peroxide (Li2O2), potassium superoxide (KO2), sulfides (Li2S and ZnS), zinc selenide (ZnSe), lithium nitride (Li3N), and aluminum phosphide (AIP). Solid products, resulting from the proceeding chemical reactions, were analyzed by X-ray diffraction, Raman spectroscopy, and SEM/EDX elemental analysis. Gaseous and volatile products were identified with the help of the TGA/MS technique. Experimental data presented in this paper provide clear evidence that fluoronanotubes are not chemically inert toward the solid matrixes studied and exhibit significant oxidative properties in the redox reactions occurring under various temperatures, depending on the nature of the inorganic compound. PMID:12908234

  15. 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.

  16. 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

  17. 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.

  18. 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. PMID:25764551

  19. Fully inorganic oxide-in-oxide ultraviolet nanocrystal light emitting devices

    NASA Astrophysics Data System (ADS)

    Brovelli, Sergio; Chiodini, Norberto; Lorenzi, Roberto; Lauria, Alessandro; Romagnoli, Marco; Paleari, Alberto

    2012-02-01

    The development of integrated photonics and lab-on-a-chip platforms for environmental and biomedical diagnostics demands ultraviolet electroluminescent materials with high mechanical, chemical and environmental stability and almost complete compatibility with existing silicon technology. Here we report the realization of fully inorganic ultraviolet light-emitting diodes emitting at 390 nm with a maximum external quantum efficiency of ~0.3%, based on SnO2 nanoparticles embedded in SiO2 thin films obtained from a solution-processed method. The fabrication involves a single deposition step onto a silicon wafer followed by a thermal treatment in a controlled atmosphere. The fully inorganic architecture ensures superior mechanical robustness and optimal chemical stability in organic solvents and aqueous solutions. The versatility of the fabrication process broadens the possibility of optimizing this strategy and extending it to other nanostructured systems for designed applications, such as active components of wearable health monitors or biomedical devices.

  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. Nickel Oxide as an Inorganic Hole Transport Layer in Organic Photovoltaics

    NASA Astrophysics Data System (ADS)

    Bailey, Brian; Widjonarko, N. Edwin; Berry, Joseph J.; Shaheen, Sean E.; Ginley, David S.; Olson, Dana C.

    2009-10-01

    This work explores the use of nickel oxide as a hole transport layer in organic photovoltaics (OPV). The purpose of the hole transport layer (HTL) is to provide an energetic barrier to electrons at the anode of the OPV device, while facilitating extraction of holes. At present, poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) is commonly used in this layer of the device, but it suffers from inherent problems in phase separation of the PEDOT and PSS components leading to non-uniform conductivity, incompatibility with various transparent conducting oxides due to its acidity, and high rate of water uptake that can accelerate degradation of interfaces and surrounding layers. Inorganic metal oxides such as nickel oxide present a potential solution to these problems. Using pulsed laser deposition (PLD) to deposit nickel oxide films, we show OPV device performance to be tunable by varying deposition parameters. Parameters explored include oxygen partial pressure during PLD, substrate temperature, film thickness, and post PLD surface treatments. These tune physical properties of the film such as work function and conductivity, which were measured directly, and in device performance.

  3. Water oxidation surface mechanisms replicated by a totally inorganic tetraruthenium–oxo molecular complex

    PubMed Central

    Piccinin, Simone; Sartorel, Andrea; Aquilanti, Giuliana; Goldoni, Andrea; Bonchio, Marcella; Fabris, Stefano

    2013-01-01

    Solar-to-fuel energy conversion relies on the invention of efficient catalysts enabling water oxidation through low-energy pathways. Our aerobic life is based on this strategy, mastered by the natural Photosystem II enzyme, using a tetranuclear Mn–oxo complex as oxygen evolving center. Within artificial devices, water can be oxidized efficiently on tailored metal-oxide surfaces such as RuO2. The quest for catalyst optimization in vitro is plagued by the elusive description of the active sites on bulk oxides. Although molecular mimics of the natural catalyst have been proposed, they generally suffer from oxidative degradation under multiturnover regime. Here we investigate a nano-sized Ru4–polyoxometalate standing as an efficient artificial catalyst featuring a totally inorganic molecular structure with enhanced stability. Experimental and computational evidence reported herein indicates that this is a unique molecular species mimicking oxygenic RuO2 surfaces. Ru4–polyoxometalate bridges the gap between homogeneous and heterogeneous water oxidation catalysis, leading to a breakthrough system. Density functional theory calculations show that the catalytic efficiency stems from the optimal distribution of the free energy cost to form reaction intermediates, in analogy with metal-oxide catalysts, thus providing a unifying picture for the two realms of water oxidation catalysis. These correlations among the mechanism of reaction, thermodynamic efficiency, and local structure of the active sites provide the key guidelines for the rational design of superior molecular catalysts and composite materials designed with a bottom–up approach and atomic control. PMID:23479603

  4. Viscosity of Hydrous Rhyolitic Melts

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Xu, Z.; Liu, Y.

    2002-12-01

    It is critical to understand and to be able to predict viscosity of hydrous silicate melts for understanding magma transport, bubble growth, volcanic eruptions, and magma fragmentation. We report new viscosity data for hydrous rhyolitic melt in the viscosity range of 109 to 1015 Pa s based on the kinetics of hydrous species reaction in the melt upon cooling (i.e., based on the equivalence between the glass transition temperature and the apparent equilibrium temperature). We also report viscosity data obtained from bubble growth experiments. Our data show that the viscosity model of Hess and Dingwell (1996) systematically overestimates the viscosity of hydrous rhyolitic melt at the high viscosity range by a factor of 2 to 4 (still within their stated 2σ uncertainty). Another problem with the model of Hess and Dingwell is that the functional dependence of viscosity on total H2O content cannot be extended to dry melt: as total H2O content decreases to zero, the viscosity would first increase, and then decrease to zero. A zero viscosity for a dry melt makes no sense. Hence we need a mixing law for hydrous melt viscosity that is extendible to dry melts. By examining the viscosity of rhyolitic melts containing 6 ppm to about 8.0 wt% total H2O (both our own data and literature data), we propose the following relation for the dependence of viscosity on total H2O content: 1/η = 1/η 1+(1/η 2-1/η 1)xn ≈ 1/η 1+xn/η 2 where η is viscosity and 1/η is fluidity, η 1 is the viscosity of the dry melt, x is the mole fraction of total dissolved H2O, n and η 2 are two fitting parameters, and η 2 can be identified to be the viscosity of the hypothetical melt consisting of pure H2O (η 2 cannot be directly measured since such a melt does not exist). The above equation appears to work well for the viscosity of hydrous rhyolitic melts. By fitting hydrous rhyolitic melt viscosity with the above equation, we find that rhyolitic melt viscosity vary by 1.2 orders of magnitude

  5. Oxidative effects of inorganic and organic contaminants on haemolymph of mussels.

    PubMed

    Kaloyianni, M; Dailianis, S; Chrisikopoulou, E; Zannou, A; Koutsogiannaki, S; Alamdari, D H; Koliakos, G; Dimitriadis, V K

    2009-05-01

    We applied a newly-established method in haemolymph of mussels, Mytilus galloprovincialis, exposed to different concentrations of heavy metals, such as zinc and cadmium and organic pollutants, such as PAHs and lindane, for the detection of total antioxidant capacity (TAC). The susceptibility of exposed mussels was increased in relation to oxidative stress induced by contaminants tested. Oxidative modifications of proteins were estimated by measuring protein carbonyl content (PCC) and malondialdehyde levels (MDA). For PCC measurement, a highly sensitive and accurate ELISA method, which requires only 5 microg of protein, was used. The significant increase of PCC and MDA in haemolymph of exposed mussels reinforces its role as biomarkers of oxidative stress. Significant correlation of TAC assay, PCC and MDA was conducted in order to evaluate the utility of PCC and TAC assay, used in the present study, as tools for determining oxidative effects of pollutants in mussels. The results reinforce the application of PCC method as useful tool for the determination of PCC alterations in haemolymph of mussels exposed to different levels of contaminants. In addition, the TAC method gives encouraging results, concerning its ability to predict antioxidant efficiency in haemolymph of mussels exposed to inorganic and organic contaminants. PMID:19358338

  6. Hybrid flow system for automatic dynamic fractionation and speciation of inorganic arsenic in environmental solids.

    PubMed

    Zhang, Yanlin; Miró, Manuel; Kolev, Spas D

    2015-03-01

    An integrated flow analysis system and protocol are proposed for the first time for automatic dynamic flow-through fractionation of inorganic arsenic (arsenite and arsenate) in environmental solids in combination with its real-time speciation. Four extractants (i.e., (1) 0.05 M ammonium sulfate, (2) 0.05 M ammonium dihydrogen phosphate, (3) 0.2 M ammonium oxalate, and (4) a mixture of 0.2 M ammonium oxalate and 0.1 M ascorbic acid at 96 °C) are applied sequentially to the sample to measure bioaccessible inorganic arsenic associated with (1) nonspecifically sorbed phases, (2) specifically sorbed phases, (3) amorphous plus poorly crystalline hydrous oxides of iron and aluminum, and (4) well-crystallized hydrous oxides of Fe and Al, respectively. The kinetic extraction profiles of arsenite and total inorganic arsenic are obtained for each extractant by automatic collection of a given number of its aliquots (subfractions) exposed to the solid sample. Arsenite and total inorganic arsenic in each subfraction are converted to arsine sequentially by hydride generation at pH 4.50 and in 1.14 M hydrochloric acid, respectively. Arsine is absorbed into a potassium permanganate solution, the discoloration of which is related to the concentration of the corresponding arsenic species. The proposed method is successfully validated by analyzing a soil reference material (NIST 2710a) and a sediment sample. PMID:25649028

  7. Liquid crystal orientation on solution processed zinc oxide inorganic films according to molecular concentration

    NASA Astrophysics Data System (ADS)

    Lee, Jong-Jin; Han, Jae-Jun; Park, Hong-Gyu; Kim, Dai-Hyun; Byun, Sang-Un; Seo, Dae-Shik

    2013-10-01

    In this paper we present the characteristics of molar concentration-dependent zinc oxide (ZnO) inorganic films deposited by the solution process for application in liquid crystal displays. ZnO surfaces supported homogeneously aligned liquid crystal (LC) molecules based on an ion-beam (IB) irradiation system. Uniform LC alignment was obtained at ZnO molar concentrations greater than 0.25 mol l-1. X-ray photoelectron spectroscopic (XPS) analysis revealed that changes in the orientation of LC molecules occurred on the ZnO layer. The electro-optic characteristics of the aligned homogenous LCs and twisted nematic (TN) mode based on the ZnO layer were comparable to those based on polyimide, which showed good potential as ZnO surfaces as an alignment layer.

  8. 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.

  9. 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.

  10. Application of inorganic oxidants to the spectrophotometric determination of ribavirin in bulk and capsules.

    PubMed

    Darwish, Ibrahim A; Khedr, Alaa S; Askal, Hassan F; Mohamed, Ramadan M

    2006-01-01

    Eight spectrophotometric methods for determination of ribavirin have been developed and validated. These methods were based on the oxidation of the drug by different inorganic oxidants: ceric ammonium sulfate, potassium permanganate, ammonium molybdate, ammonium metavanidate, chromium trioxide, potassium dichromate, potassium iodate, and potassium periodate. The oxidation reactions were performed in perchloric acid medium for ceric ammonium sulfate and in sulfuric acid medium for the other reagents. With ceric ammonium sulfate and potassium permanganate, the concentration of ribavirin in its samples was determined by measuring the decrease in the absorption intensity of the colored reagents at 315 and 525 nm, respectively. With the other reagents, the concentration of ribavirin was determined by measuring the intensity of the developed colored reaction products at the wavelengths of maximum absorbance: 675, 780, 595, 595, 475, and 475 nm for reactions with ammonium molybdate, ammonium metavanidate, chromium trioxide, potassium dichromate, potassium iodate, and potassium periodate, respectively. Different variables affecting the reaction conditions were carefully studied and optimized. Under the optimum conditions, linear relationships with good correlation coefficients (0.9984-0.9998) were found between the absorbance readings and the concentrations of ribavirin in the range of 4-1400 microg/mL. The molar absorptivities were correlated with the oxidation potential of the oxidants used. The precision of the methods were satisfactory; the values of relative standard deviation did not exceed 1.64%. The proposed methods were successfully applied to the analysis of ribavirin in pure drug material and capsules with good accuracy and precision; the recovery values were 99.2-101.2 +/- 0.48-1.30%. The results obtained using the proposed spectrophotometric methods were comparable with those obtained with the official method stated in the United States Pharmacopeia. PMID

  11. Effect of inorganic carbon on anaerobic ammonium oxidation enriched in sequencing batch reactor.

    PubMed

    Liao, Dexiang; Li, Xiaoming; Yang, Qi; Zeng, Guangming; Guo, Liang; Yue, Xiu

    2008-01-01

    The present lab-scale research reveals the enrichment of anaerobic ammonium oxidation microorganism from methanogenic anaerobic granular sludge and the effect of inorganic carbon (sodium bicarbonate) on anaerobic ammonium oxidation. The enrichment of anammox bacteria was carried out in a 7.0-L sequencing batch reactor (SBR) and the effect of bicarbonate on anammox was conducted in a 3.0-L SBR. Research results, especially the biomass, showed first signs of anammox activity after 54 d cultivation with synthetic wastewater, when the pH was controlled between 7.5 and 8.3, the temperature was 35 degrees C. The anammox activity increased as the influent bicarbonate concentration increased from 1.0 to 1.5 g/L, and then, was inhibited as the bicarbonate concentration approached 2.0 g/L. However, the activity could be restored by the reduction of bicarbonate concentration to 1.0 g/L, as shown by rapid conversion of ammonium, and nitrite and nitrate production with normal stoichiometry. The optimization of the bicarbonate concentration in the reactor could increase the anammox rate up to 66.4 mgN/(L x d). PMID:18817072

  12. 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. PMID:26956550

  13. 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.

  14. 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)

  15. 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

  16. 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.

  17. Ultrafast Spectroscopy and Energy Transfer in an Organic/Inorganic Composite of Zinc Oxide and Graphite Oxide

    NASA Astrophysics Data System (ADS)

    Secor, Jeff A.

    This thesis describes the ultrafast processes in a hybrid organic/inorganic composite of Zinc (hydr)oxide and graphite oxide. The zinc phase is a large bandgap semi-conductor metal oxide with broadband visible emission from 430 - 600 nm caused by large density of surface and defects that act as trap states within the bandgap of the metal oxide. These surface states are observed to be brightly luminescent with long lifetimes. Steady state absorption, emission and Raman scattering provide a first look into the nature and effects of the hybridized defect states. Different luminescent structures are observed when the energy of excitation lies below the fundamental band edge of the zinc phase eventhough there is no structure in the absorption spectra caused by these intermediate states. This is analyzed with tunable laser excitation energy and the appearance of the blue-shifted emission with sub band gap excitation energies is attributed to a range of defect levels and the charge transfer state near the band edge of ZnO that becomes unaccessible under resonant absorption due to band bending effects of the excited electrons in the conduction band. In the time domain, the composite system GO shows very long and reversible nanosecond decay characteristics of the GO and shortened decay processes in the zinc phase. It is hypothesized that the overlap of the defect states of the two materials leads to strong interaction of the dense defect states of each material. To analyze this, spectrally and polarization resolved ultrafast decays are compared between the components in neat form and in composite form to give details on the ultrafast transfer/decay processes. The lifetimes of the different spectral regions of the emission show multi-exponential behavior that can be grouped into three energy regions: the zinc phase exciton, the charge transfer/ surface state overlap emission, and the defect level emission. Comparison of each region as a function of excitation energy build up

  18. 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

  19. 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. PMID:27127031

  20. Effects of inorganic carbon limitation on anaerobic ammonium oxidation (anammox) activity.

    PubMed

    Kimura, Yuya; Isaka, Kazuichi; Kazama, Futaba

    2011-03-01

    Anammox bacteria are chemoautotrophic bacteria that oxidize ammonium with nitrite as the electron acceptor and with CO(2) as the main carbon source. The effects of inorganic carbon (IC) limitation on anammox bacteria were investigated using continuous feeding tests. In this study, a gel carrier with entrapped anammox sludge was used. It was clearly shown that the anammox activity deteriorated with a decrease in the influent IC concentration. The relationship between the influent IC concentration and the anammox activity was analyzed using Michaelis-Menten kinetics, and the apparent K(m) was determined to be 1.2mg-C/L. The activity could be recovered by adding IC to the influent. The consumption ratio of IC to ammonium was not constant and mainly depended on the influent ratio of the IC to ammonium concentrations (inf.IC/inf.NH(4)-N). The results indicated that an inf.IC/inf.NH(4)-N ratio of 0.2 in the anammox reactor was ideal for the anammox process using gel cubes. PMID:21256745

  1. Electrical resistivity of assembled transparent inorganic oxide nanoparticle thin layers: Influence of silica, insulating impurities and surfactant layer thickness

    PubMed Central

    Bubenhofer, Stephanie B.; Schumacher, Christoph M.; Koehler, Fabian M.; Luechinger, Norman A.; Sotiriou, Georgios A.; Grass, Robert N.; Stark, Wendelin J.

    2013-01-01

    Transparent, conductive layers prepared from nanoparticle dispersion of doped oxides are highly sensitive to impurities. Currently investigated cost efficient and fast production of thin conducting films for use in consumer electronics relies on wet processing such as spin and/or dip coating of surfactant-stabilized nanoparticle dispersions. This inherently results in entrainment of organic and inorganic impurities into the conducting layer leading to largely varying electrical conductivity. Therefore this study provides a systematic investigation on the effect of insulating surfactants, small organic molecules and silica in terms of pressure dependent electrical conductivity as a result of different core/shell structure (layer thickness). Application of high temperature flame synthesis gives access to antimony-doped tin oxide (ATO) nanoparticles with high purity. This well-defined starting material was then subjected to representative film preparation processes using organic additives. In addition ATO nanoparticles were prepared with a homogeneous inorganic silica layer (silica layer thickness from 0.7 to 2 nm). Testing both organic and inorganic shell materials for the electronic transport through the nanoparticle composite allowed a systematic study on the influence of surface adsorbates (e.g. organic, insulating materials on the conducting nanoparticle’s surface) in comparison to well-known insulators such as silica. Insulating impurities or shells revealed a dominant influence of tunneling effect on the overall layer resistance. Mechanical relaxation phenomena were found for 2 nm insulating shells for both large polymer surfactants and (inorganic) SiO2 shells. PMID:22545730

  2. "Black-colored olivines" in peridotites: dehydrogenation from hydrous olivines

    NASA Astrophysics Data System (ADS)

    Arai, Shoji; Hoshikawa, Chihiro; Miura, Makoto

    2015-04-01

    Fresh olivines that are black to the naked eye are found in some dunites. Peridotites are easily converted to be black in color, when serpentinized, due to production of secondary fine magnetite particles. The dunites that contain fresh but black-colored olivines are usually coarse-grained. These coarse olivine grains are sometimes very heterogeneous in color; the blackish part grades to whitish parts in single grains. The black color is due to homegeneous distribution of minute (< 10 microns) black particles in olivine. They are rod-like or plate-like in shape in thin section, sometimes being aligned under crystallographic control of the host olivine. Olivines are clear and free of these inclusions around primary chromian spinel inclusions or chromian spinel lamellae (Arai, 1978). Raman spectroscopy indicates the minute black particles are magnetite always associated with diopside. It is interesting to note that olivine in mantle peridotites accompanied by the black-colored dunites is totally free of the black inclusions, giving the ordinary colors (pale yellow to whitish) of Mg-rich olivine. It is not likely that the magnetite inclusions formed through secondary oxidation of olivine by invasion of oxygen, which is possible along cracks or grain boundaries. They most probably formed due to dehydrogenation from primary OH-bearing olivines upon cooling. Hydrogen was quickly diffused out from the olivines to leave magnetite and excess silica. The excess silica was possibly combined with a monticellite component to form diopside. The OH-bearing (hydrous) olivines can be precipitated from hydrous magmas, and the hydrous nature of the magma can promote an increase in grain size due to faster diffusion of elements. The minute inclusions of magnetite + diopside is thus an indicator of primary hydrous character of host olivine.

  3. Hydrous reactive flow and magmatic channelisation

    NASA Astrophysics Data System (ADS)

    Katz, Richard; Manning, Craig; Spiegelman, Marc; Kelemen, Peter

    2010-05-01

    It is broadly accepted that the dominant mechanism of melt production in subduction zones is hydrous flux melting. This type of melting occurs when hydrous fluids, released by metamorphic reactions in the subducting slab, metasomatize the mantle wedge. As hydrous fluid rises off the subducting slab it encounters higher temperatures within the mantle. The volatile elements in the hydrous fluid (principally water) depress the solidus of the mantle and cause melting. This can be thought of as a reactive flow process whereby a chemically reactive liquid migrates through a soluble matrix, up a solubility gradient---with increasing temperature, the hydrous fluid becomes increasingly undersaturated in silicate rock components. The fluid is therefore corrosive and hydrous melting is understood as a dissolution process. Under these conditions, the flow can be affected by the Reactive Infiltration Instability, which leads to channelization. In this talk I introduce a themochemical/fluid dynamical model to investigate this scenario and show that for plausible conditions in the mantle wedge, channelized magmatic transport is expected.

  4. 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.

  5. 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...

  6. 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. PMID:15375674

  7. 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.

  8. Magnetic resonance studies of inorganic oxides and a new pulse programming system for pulsed EMR

    NASA Astrophysics Data System (ADS)

    Schwartz, Dwight Allen

    We have investigated several inorganic oxide systems using nuclear and electron magnetic resonance spectroscopies and also report a new pulse programming system for a pulsed S-band EMR spectrometer. We show in a study of simple perovskites (Ca,Sr,Ba)(Ti,Zr) Osb3 that magic-angle spinning O-17 NMR provides unique, highly-resolved spectra in these materials and gives evidence of being useful as a diagnostic tool in mixed phase materials (Asb{x}Asbsp{1-x}{'})BOsb3. Various used NMR and EMR techniques to study of the commercial borosilicate glasses CGW-3320, CGW-7502, CGW-7740 (Pyrex) and GSC-4, and T-08 (pure silica glass) which had received 5-10 gigarad doses of Co-60 gamma-radiation in the presence and absence of hydrogen gas. We show that B-11, Al-27 and Si-29 MAS NMR spectra contain indications of structural changes in these glasses as a result of large doses of radiation. We also observed the reduction of trace Ti(IV) to Ti(III) when Hsb2 gas was present during irradiation of glass samples. Static NMR and EMR studies in the (Na,Li)POsb3 system indicate a possible mixed alkali effect in the spin-lattice relaxation of Na-23 in NaPOsb3 and Lisb{0.4}Nasb{0.6}POsb3. Static Na-23 NMR studies of NaPOsb3 reveal the presence of different structural or dynamical environments as a function of temperatures between 23-566 C. We have investigated glass and glass fibers of Lisb{0.6}Nasb{0.4}POsb3 and Na(Psb{0.99},Vsb{0.01})Osb3, and show P-31 NMR and EMR evidence that these materials remained structurally isotropic when pulled into fibers. We show that vanadium (in Na(Psb{0.99},Vsb{0.01})Osb3) appears to suppress radiolytic unpaired electron and hole defect production which does take place in nominally vanadium-free NaPOsb3 during small doses of gamma-radiation. We describe hardware and software developed for a pulse programming system for a pulsed S-band EMR spectrometer. This system supports user-programmable automatic independent control of all pulse sequence parameters

  9. Development and testing of spheroidal inorganic sorbents

    SciTech Connect

    Collins, J.L.; Anderson, K.K.

    1998-01-29

    The general objectives of this task are to develop, prepare, and test spheroidal inorganic ion exchangers made by the HMTA (hexamethylenetetramine) internal gelation process to remove radionuclides and heavy metals from waste streams occurring at the various DOE sites. Inorganic ion-exchange materials, such as sodium silicotitanate, sodium titanate, ammonium molybdeophosphate, phosphotungstic acid, hexacyanoferrates, titanium monohydrogen phosphate, hydrous titanium oxide, polyantimonic acid, magnesium oxide, etc. have high selectivities and efficiencies for separating and removing radionuclides (e.g., cesium, strontium, technetium, iodine, europium, cerium, ruthenium, and zirconium), actinides, and other elements (such as lead, mercury, silver, nickel, zinc, chromium, and fluoride) from aqueous waste streams. The development of cesium specific spherical sorbents for treatment of acidic, high-salt waste solutions was initiated in FY 1998. Acid-side treatment is important at INEEL and could become important if acidic sludge washing were to become a treatment option at Hanford, Savannah River, or Oak Ridge. Zirconium monohydrogen phosphates (ZrHP) embedded with ammonium molybdophosphate (AMP) was the cesium selective inorganic sorbent chosen for making microspheres. AMP is known to be a very effective sorbent for removing cesium from waste streams over a wide range of acidity and salinity, and it has very rapid loading kinetics. The cesium can also be eluted from AMP with ammonium salt solutions. AMP cannot be used as a sorbent at pHs above 7 because it decomposes. In the pH range of 1 to 7, ZrHP is also a very effective sorbent for removing Cs, Sr, Th, U(VI), Pu(IV), AM(III), Hg, and Pb from streams of lower ionic concentrations.

  10. 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.

  11. Stress proteins and oxidative damage in a renal derived cell line exposed to inorganic mercury and lead.

    PubMed

    Stacchiotti, Alessandra; Morandini, Fausta; Bettoni, Francesca; Schena, Ilaria; Lavazza, Antonio; Grigolato, Pier Giovanni; Apostoli, Pietro; Rezzani, Rita; Aleo, Maria Francesca

    2009-10-29

    A close link between stress protein up-regulation and oxidative damage may provide a novel therapeutic tool to counteract nephrotoxicity induced by toxic metals in the human population, mainly in children, of industrialized countries. Here we analysed the time course of the expression of several heat shock proteins, glucose-regulated proteins and metallothioneins in a rat proximal tubular cell line (NRK-52E) exposed to subcytotoxic doses of inorganic mercury and lead. Concomitantly, we used morphological and biochemical methods to evaluate metal-induced cytotoxicity and oxidative damage. In particular, as biochemical indicators of oxidative stress we detected reactive oxygen species (ROS) and nitrogen species (RNS), total glutathione (GSH) and glutathione-S-transferase (GST) activity. Our results clearly demonstrated that mercury increases ROS and RNS levels and the expressions of Hsp25 and inducible Hsp72. These findings are corroborated by evident mitochondrial damage, apoptosis or necrosis. By contrast, lead is unable to up-regulate Hsp72 but enhances Grp78 and activates nuclear Hsp25 translocation. Furthermore, lead causes endoplasmic reticulum (ER) stress, vacuolation and nucleolar segregation. Lastly, both metals stimulate the over-expression of MTs, but with a different time course. In conclusion, in NRK-52E cell line the stress response is an early and metal-induced event that correlates well with the direct oxidative damage induced by mercury. Indeed, different chaperones are involved in the specific nephrotoxic mechanism of these environmental pollutants and work together for cell survival. PMID:19720107

  12. Inorganic Nitrate Promotes the Browning of White Adipose Tissue through the Nitrate-Nitrite-Nitric Oxide Pathway

    PubMed Central

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

    2015-01-01

    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 define 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 co-morbidity 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. Since resulting beige/brite cells exhibit anti-obesity and anti-diabetic effects, nitrate may be an effective means of inducing the browning response in adipose tissue to treat the metabolic syndrome. PMID:25249574

  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. PMID:24651714

  14. Revisiting the catalytic CuZ cluster of nitrous oxide (N2O) reductase. Evidence of a bridging inorganic sulfur.

    PubMed

    Brown, K; Djinovic-Carugo, K; Haltia, T; Cabrito, I; Saraste, M; Moura, J J; Moura, I; Tegoni, M; Cambillau, C

    2000-12-29

    Nitrous-oxide reductases (N2OR) catalyze the two-electron reduction of N(2)O to N(2). The crystal structure of N2ORs from Pseudomonas nautica (Pn) and Paracoccus denitrificans (Pd) were solved at resolutions of 2.4 and 1.6 A, respectively. The Pn N2OR structure revealed that the catalytic CuZ center belongs to a new type of metal cluster in which four copper ions are liganded by seven histidine residues. A bridging oxygen moiety and two other hydroxide ligands were proposed to complete the ligation scheme (Brown, K., Tegoni, M., Prudencio, M., Pereira, A. S., Besson, S., Moura, J. J. G., Moura, I., and Cambillau, C. (2000) Nat. Struct. Biol. 7, 191-195). However, in the CuZ cluster, inorganic sulfur chemical determination and the high resolution structure of Pd N2OR identified a bridging inorganic sulfur instead of an oxygen. This result reconciles the novel CuZ cluster with the hitherto puzzling spectroscopic data. PMID:11024061

  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. PMID:27267149

  16. Influence of albumin and inorganic ions on electrochemical corrosion behavior of plasma electrolytic oxidation coated magnesium for surgical implants

    NASA Astrophysics Data System (ADS)

    Wan, Peng; Lin, Xiao; Tan, LiLi; Li, Lugee; Li, WeiRong; Yang, Ke

    2013-10-01

    Magnesium and its alloys are of great interest for biodegradable metallic devices. However, the degradation behavior and mechanisms of magnesium treated with coating in physiological environment in the presence of organic compound such as albumin have not been elucidated. In this study, the plasma electrolytic oxidation coated magnesium immersed in four different simulated body fluids: NaCl, PBS and with the addition of albumin to investigate the influence of protein and inorganic ions on degradation behavior by electrochemical methods. The results of electrochemical tests showed that aggressive corrosion took place in 0.9 wt.% NaCl solution; whereas albumin can act as an inhibitor, its adsorption impeded further dissolution of the coating. The mechanism was attributed to the synergistic effect of protein adsorption and precipitation of insoluble salts.

  17. 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

  18. 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

  19. Nanostructural surface engineering of grafted polymers on inorganic oxide substrates for membrane separations

    NASA Astrophysics Data System (ADS)

    Yoshida, Wayne Hiroshi

    Nanostructural engineering of inorganic substrates by free radical graft polymerization was studied with the goal of developing new membrane materials for pervaporation. Graft polymerization consisted of modification of surface hydroxyls with vinyl trimethoxysilane, followed by solution graft polymerization reaction using either vinyl acetate (VAc) or vinyl pyrrolidone (VP). The topology of the modified surfaces was studied by atomic force microscopy (AFM) on both atomically smooth silicon wafer substrates and microporous inorganic membrane supports in order to deduce the effects of modification on the nanostructural properties of the membrane. While unmodified wafers showed a root-mean-square (RMS) surface roughness of 0.21 +/- 0.03 nm, roughness increased to 3.15 +/- 0.23 nm upon silylation. Under poor solvent conditions (i.e., air), surfaces modified with higher poly(vinyl acetate) (PVAc) or poly(vinyl pyrrolidone) (PVP) polymer graft yields displayed lateral inhomogeneities in the polymer layer. Although RMS surface roughness was nearly identical (0.81--0.85 nm) for PVAc-modified surfaces grafted at different monomer concentrations, the skewness of the height distribution decreased from 2.22 to 0.78 as polymer graft yield increased from 0.8 to 3.5 mg/m2. The polymer-modified surfaces were used to create inorganic pervaporation membranes consisting of a single macromolecular separation layer formed by graft polymerization. PVAc grafted silica membranes (500A native pore size) were found selective for MTBE in the separation of 0.1--1% (v/v) MTBE from water, achieving MTBE enrichment factors as high as 371 at a permeate flux of 0.38 l/m2 hr and a Reynolds number of 6390; however, these membranes could not separate anhydrous organic mixtures. Pervaporative separation of methanol/MTBE mixtures was possible with PVAc and PVP-modified alumina supports of 50A native pore size, where the separation layer consisted of grafted polymer chains with estimated radius of

  20. 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.

  1. 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

  2. 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.

  3. 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

  4. 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.

  5. 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.

  6. Adsorption behavior and mechanism of perfluorooctane sulfonate on nanosized inorganic oxides.

    PubMed

    Lu, Xinyu; Deng, Shubo; Wang, Bin; Huang, Jun; Wang, Yujue; Yu, Gang

    2016-07-15

    Adsorption of perfluorooctane sulfonate (PFOS) on manufactured nanoparticles (NPs) is critical for understanding their transport and fate in aquatic environments. In this study, the adsorption behavior of PFOS on nanosized Al2O3, Fe2O3, SiO2 and TiO2 was examined in terms of adsorption isotherms and influences of pH, ionic strength and heavy metallic cations. The nano-oxides had much higher adsorption capacities than bulk particles due to higher surface hydroxyl density. PFOS adsorption showed strong pH dependence due to different species of surface hydroxyl groups on nano-oxides. Besides electrostatic interaction, sulfonic group of PFOS possibly formed hydrogen bonds on the surface of nano-oxides. Because of the bridging effect in the co-adsorption process, the coexisting PFOS and heavy metallic cations greatly enhanced their adsorption onto the nano-oxides. Comparative adsorption of different perfluorinated sulfonates indicated the possible formation of bilayer PFOS adsorption on the nano-oxides, leading to the enhanced Cu(II) adsorption on the sulfonic groups of PFOS on the surfaces through electrostatic interaction. PMID:27127908

  7. N2O production by ammonia oxidizing bacteria in an enriched nitrifying sludge linearly depends on inorganic carbon concentration.

    PubMed

    Peng, Lai; Ni, Bing-Jie; Ye, Liu; Yuan, Zhiguo

    2015-05-01

    The effect of inorganic carbon (IC) on nitrous oxide (N2O) production by ammonia oxidizing bacteria (AOB) was investigated over a concentration range of 0-12 mmol C/L, encompassing typical IC levels in a wastewater treatment reactors. The AOB culture was enriched along with nitrite-oxidizing bacteria (NOB) in a sequencing batch reactor (SBR) to perform complete nitrification. Batch experiments were conducted with continuous carbon dioxide (CO2) stripping or at controlled IC concentrations. The results revealed a linear relationship between N2O production rate (N2OR) and IC concentration (R(2) = 0.97) within the IC range studied, suggesting a substantial effect of IC on N2O production by AOB. Similar results were also obtained with an AOB culture treating anaerobic sludge digestion liquor. The fundamental mechanism responsible for this dependency is unclear; however, in agreement with previous studies, it was observed that the ammonia oxidation rate (AOR) was also influenced by the IC concentration, which could be well described by the Monod kinetics. These resulted in an exponential relationship between N2OR and AOR, as previously observed in experiments where AOR was altered by varying dissolved oxygen and ammonia concentrations. It is therefore possible that IC indirectly affected N2OR by causing a change in AOR. The observation in this study indicates that alkalinity (mostly contributed by IC) could be a significant factor influencing N2O production and should be taken into consideration in estimating and mitigating N2O emissions in wastewater treatment systems. PMID:25706224

  8. 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.

  9. 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

  10. Water-melt interaction in hydrous magmatic systems at high temperature and pressure

    NASA Astrophysics Data System (ADS)

    Mysen, Bjorn

    2014-12-01

    Experimental data on the structure and properties of melts and fluids relevant to water-melt interaction in hydrous magmatic systems in the Earth's interior have been reviewed. Complex relationships between water solubility in melts and their bulk composition [Al/Si-ratio, metal oxide/(Al + Si) and electron properties of metal cations] explain why water solubility in felsic magmas such as those of rhyolite and andesite composition is significantly greater than the water solubility in basalt melts. The silicate solubility in aqueous fluid is also significantly dependent on composition with metal oxide/(Al + Si) and electron properties of the metal cations, the dominant variables. Hydrogen bonding is not important in hydrous fluids and melts at temperatures above 500°C to 550°C and does not, therefore, play a role in hydrous magmatic systems. The properties of hydrous melts and aqueous solutions are governed by how the silicate speciation ( Q n species, where n is the number of bridging oxygen in an individual species) varies with bulk composition, silicate composition, temperature, and pressure. The reactions that describe the interactions are similar in melts, fluids, and supercritical fluids. The degree of melt polymerization caused by dissolved water varies with melt composition and total water content. Silicate- and alkali-rich felsic magmatic melts are more sensitive to water content than more mafic magmas. Transport and configurational properties of hydrous magmatic melts can be modeled with the aid of the Q n speciation variations. Liquidus and melting phase relations of hydrous systems also can be described in such terms, as can minor and trace element partition coefficients. Stable isotope fractionation (e.g., D/H) can also be rationalized in this manner. Critical to these latter observations is the high silicate concentration in aqueous fluids. These components can enhance solubility of minor and trace elements by orders of magnitude and change the

  11. Tillage and Inorganic Nitrogen Source Effects on Nitrous Oxide Emissions from Irrigated Cropping Systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nitrous oxide (N2O) emissions were monitored from irrigated corn production systems receiving different N sources at fertilizer rates of 246 kg N ha-1 when in corn (Zea mays L.), 56 kg N ha-1 when in dry bean (Phaseolus vulgaris L.), and 157 kg N ha-1 when in barley (Hordeum distichon L.). Croppin...

  12. 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.

  13. 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.

  14. Easily processable multimodal spectral converters based on metal oxide/organic-inorganic hybrid nanocomposites.

    PubMed

    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 Er(3+), Yb(3+) 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 Er(3+)- and Yb(3+)-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. PMID:26374133

  15. 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

  16. 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

  17. 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

  18. 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

  19. 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.

  20. 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.

  1. 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

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

    PubMed

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

    2016-08-01

    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). PMID:27009374

  3. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

    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.

  5. Improvement of device performance by using zinc oxide in hybrid organic-inorganic solar cells

    NASA Astrophysics Data System (ADS)

    Hayakawa, Akinobu; Sagawa, Takashi

    2016-02-01

    Zinc oxide (ZnO) nanopowder was applied to hybrid solar cells in combination with poly(3-hexylthiophene). Stability tests of the hybrid solar cell with or without encapsulation with glass and UV cut-off films were performed under 1 sun at 63 °C at a relative humidity of 50%. It was found that the sealed cell showed worse device performance in terms of the loss of the open-circuit voltage (Voc), whereas the unsealed cell exposed to air retained an almost constant Voc for more than 3 d under dark and atmospheric conditions. Placement in O2 atmosphere in the dark led to the recovery of Voc. Cation (Sn4+) doping into ZnO was performed, and the loss of Voc was effectively suppressed through the restraint of the supply of the excited electron from the valence band to the conduction band.

  6. 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

    2015-01-01

    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. PMID:25583370

  7. Parameters of oxidative stress variation depending on the concentration of inorganic zinc compounds

    PubMed Central

    Grigorescu, R; Gruia, MI; Nacea, V; Nitu, C

    2015-01-01

    Zinc deficiency is a problem faced by a large number of people, a U.S. study showing that only 46% of the population aged over 71 years has the best amount of zinc in the body. Due to the very complex role of zinc deficiency in this trace, it can occur through a variety of symptoms affecting multiple body functions. Zinc was demonstrated to have the ability to neutralize free radicals protecting the body from the harmful effects of these effects, ultimately leading to atherosclerosis and cardiovascular disease derived from premature aging, the immune and immune disorders and increased risk of cancer. The purpose of the paper is to identify the role of antioxidant systems, with Zn2+ ions in the center of defense and decrease oxidative stress in dynamic interaction with malignant transformed cells. PMID:26664468

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

    PubMed Central

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

    2015-01-01

    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. PMID:25583370

  9. 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

  10. 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

  11. Inorganic/Organic Hybrid Silica Nanoparticles as a Nitric Oxide Delivery Scaffold.

    PubMed

    Shin, Jae Ho; Schoenfisch, Mark H

    2008-01-01

    The preparation and characterization of nitric oxide (NO)-releasing silica particles formed following the synthesis of N-diazeniumdiolate-modified aminoalkoxysilanes are reported. Briefly, an aminoalkoxysilane solution was prepared by dissolving an appropriate amount of aminoalkoxysilane in a mixture of ethanol, methanol, and sodium methoxide (NaOMe) base. The silane solution was reacted with NO (5 atm) to form N-diazeniumdiolate NO donor moieties on the amino-alkoxysilanes. Tetraethoxy- or tetramethoxysilane (TEOS or TMOS) was then mixed with different ratios of N-diazeniumdiolate-modified aminoalkoxysilane (10 - 75 mol%, balance TEOS or TMOS). Finally, the silane mixture was added into ethanol in the presence of an ammonia catalyst to form NO donor silica nanoparticles via a sol-gel process. This synthetic approach allows for the preparation of NO delivery silica scaffolds with remarkably improved NO storage and release properties, surpassing all macromolecular NO donor systems reported to date with respect to NO payload (11.26μmol·mg(-1)), maximum NO release amount (357000 ppb·mg(-1)), NO release half-life (253 min), and NO release duration (101 h). The N-diazeniumdiolate-modified silane monomers and the resulting silica nanoparticles were characterized by (29)Si nuclear magnetic resonance (NMR) spectroscopy, UV-visible spectroscopy, chemiluminescence, atomic force microscopy (AFM), gas adsorption-desorption isotherms, and elemental analysis. PMID:23833394

  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. Spherical silica particles decorated with graphene oxide nanosheets as a new sorbent in inorganic trace analysis.

    PubMed

    Sitko, Rafal; Zawisza, Beata; Talik, Ewa; Janik, Paulina; Osoba, Grzegorz; Feist, Barbara; Malicka, Ewa

    2014-06-27

    Graphene oxide (GO) is a novel material with excellent adsorptive properties. However, the very small particles of GO can cause serious problems is solid-phase extraction (SPE) such as the high pressure in SPE system and the adsorbent loss through pores of frit. These problems can be overcome by covalently binding GO nanosheets to a support. In this paper, GO was covalently bonded to spherical silica by coupling the amino groups of spherical aminosilica and the carboxyl groups of GO (GO@SiO2). The successful immobilization of GO nanosheets on the aminosilica was confirmed by scanning electron microscopy and X-ray photoelectron spectroscopy. The spherical particle covered by GO with crumpled silk wave-like carbon sheets are an ideal sorbent for SPE of metal ions. The wrinkled structure of the coating results in large surface area and a high extractive capacity. The adsorption bath experiment shows that Cu(II) and Pb(II) can be quantitatively adsorbed at pH 5.5 with maximum adsorption capacity of 6.0 and 13.6 mg g(-1), respectively. Such features of GO nanosheets as softness and flexibility allow achieving excellent contact with analyzed solution in flow-rate conditions. In consequence, the metal ions can be quantitatively preconcentrated from high volume of aqueous samples with excellent flow-rate. SPE column is very stable and several adsorption-elution cycles can be performed without any loss of adsorptive properties. The GO@SiO2 was used for analysis of various water samples by flame atomic absorption spectrometry with excellent enrichment factors (200-250) and detection limits (0.084 and 0.27 ng mL(-1) for Cu(II) and Pb(II), respectively). PMID:24928241

  15. 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

  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. 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.

  18. 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

  19. 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

  20. Bioinspired heme, heme/nonheme diiron, heme/copper, and inorganic NOx chemistry: *NO((g)) oxidation, peroxynitrite-metal chemistry, and *NO((g)) reductive coupling.

    PubMed

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

    2010-07-19

    The focus of this Forum Article 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 (NODs) and (ii) reductive coupling of two molecules of *NO((g)) to give N(2)O(g). In the former case, NODs are described, and the highlighting of possible peroxynitrite/heme intermediates and the consequences of this are given by a 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 O(2)(g), leading to peroxynitrite species, are given. The coverage of biological reductive coupling of *NO((g)) deals with bacterial nitric oxide reductases (NORs) with heme/nonheme diiron active sites and on heme/copper oxidases such as cytochrome c oxidase, which can mediate the same chemistry. Recently designed protein and synthetic model compounds (heme/nonheme/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, that 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

  1. 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…

  2. Sol-gel processed thin-layer ruthenium oxide/carbon black supercapacitors: A revelation of the energy storage issues

    NASA Astrophysics Data System (ADS)

    Panić, V. V.; Dekanski, A. B.; Stevanović, R. M.

    Hydrous ruthenium oxide/carbon black nanocomposites were prepared by impregnation of the carbon blacks by differently aged inorganic RuO 2 sols, i.e. of different particle size. Commercial Black Pearls 2000 ® (BP) and Vulcan ® XC-72 R (XC) carbon blacks were used. Capacitive properties of BP/RuO 2 and XC/RuO 2 composites were investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in H 2SO 4 solution. Capacitance values and capacitance distribution through the composite porous layer were found different if high- (BP) and low- (XC) surface-area carbons are used as supports. The aging time (particle size) of Ru oxide sol as well as the concentration of the oxide solid phase in the impregnating medium influenced the capacitive performance of prepared composites. While the capacitance of BP-supported oxide decreases with the aging time, the capacitive ability of XC-supported oxide is promoted with increasing oxide particle size. The increase in concentration of the oxide solid phase in the impregnating medium caused an improvement of charging/discharging characteristics due to pronounced pseudocapacitance contribution of the increasing amount of inserted oxide. The effects of these variables in the impregnation process on the energy storage capabilities of prepared nanocomposites are envisaged as a result of intrinsic way of population of the pores of carbon material by hydrous Ru oxide particle.

  3. 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

  4. 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

  5. Spectral evidence for carbonates on Mars: Hydrous carbonates

    NASA Technical Reports Server (NTRS)

    Calvin, W. M.; King, T. V. V.

    1991-01-01

    Although many of the spectral features of the Martian samples studied are not unique mineralogical indicators, much of the current spectral data is consistent with (possibly abundant) hydrous carbonates on the surface of Mars. The absorption features in the measured samples were quite weak compared with those of anhydrous carbonates. The weak features imply that significantly more hydrous carbonates can be incorporated onto the surface before becoming spectrally evident; however, exact limits have yet to be determined. The stability of these materials in the Martian environment is not known, but their formation and occurrence in low temperature terrestrial environments makes them appealing candidates for weathering products on Mars.

  6. 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.

  7. 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.

  8. 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

  9. Growth and Filling Regularities of Filamentary Channels in Non-Metallic Inorganic Coatings Under Anodic Oxidation of Valve Metals. Mathematical Modeling

    NASA Astrophysics Data System (ADS)

    Mamaev, A. I.; Mamaeva, V. A.; Kolenchin, N. F.; Chubenko, A. K.; Kovalskaya, Ya. B.; Dolgova, Yu. N.; Beletskaya, E. Yu.

    2015-12-01

    Theoretical models are developed for growth and filling processes in filamentary channels of nanostructured non-metallic coatings produced by anodizing and microplasma oxidation. Graphical concentration distributions are obtained for channel-reacting anions, cations, and sparingly soluble reaction products depending on the time of electric current transmission and the length of the filamentary channel. Graphical distributions of the front moving velocity for the sparingly soluble compound are presented. The resulting model representation increases the understanding of the anodic process nature and can be used for a description and prediction of porous anodic film growth and filling. It is shown that the character of the filamentary channel growth and filling causes a variety of processes determining the textured metal - nonmetallic inorganic coating phase boundary formation.

  10. 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...

  11. 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...

  12. Ultra-hydrous stishovite obtained by hydrothermal treatment of SiO2

    NASA Astrophysics Data System (ADS)

    Spektor, K.; Nylen, J.; Stoyanov, E.; Navrotsky, A.; Hervig, R. L.; Leinenweber, K.; Holland, G. P.; Haussermann, U.

    2011-12-01

    Stishovite (SiO2) is an important high pressure mineral occurring in silica rich parts of subducted oceanic slabs and crustal fragments in the Earth's mantle. This silica polymorph adopts the rutile structure with octahedrally coordinated silicon and is generally considered to be nearly anhydrous with a maximum of 30 ppm H2O. In the presence of Al2O3, stishovite is capable of incorporating up to 0.3 wt.% of H2O. This research shows the possibility of synthesizing ultra-hydrous stishovite containing 1.3±0.2% of water without the presence of aluminum. Hydrous stishovite was unexpectedly obtained during hydrothermal treatments of either silica glass or coesite in a multi-anvil high pressure device at 10 GPa and 8 hours isothermal heating, at temperatures between 300 °C and 550 °C. Employed silica - water mixtures averaged a molar ratio of 1:1. At temperatures above 400 °C pure samples of stishovite were obtained. Optical and SEM observations showed that silica glass transforms via coesite into stishovite. Thermogravimetric analysis (TGA) and secondary ion mass spectrometry (SIMS) results were in good agreement, giving 1.3(2) wt.% of incorporated H2O for hydrous stishovite samples obtained at 450 °C. Hydrous stishovite has a slightly larger unit cell volume compared to conventionally prepared, dry, stishovite (0.5 to 0.8%). Infrared spectra (IR) showed intense OH stretching bands in 2500-3500 cm-1 region. Oxide melt drop solution calorimetry results show very modest (< 10 kJ per mole of SiO2) energetic destabilization associated with the observed H2O incorporation. On the other hand, the pV term at room temperature and 10 GPa is estimated to be about - 7 kJ/mol and thus can overcome the destabilizing enthalpy at atmospheric pressure. NMR data on the hydrous stishovite indicates that an octahedral Si vacancy is balanced by a cluster of 4 H atoms in a hydrogarnet-type defect. 1H NMR shows clustering of the hydrogen nuclei where the H-H distances are below 3 Å. 29Si

  13. A novel control method for nitritation: The domination of ammonia-oxidizing bacteria by high concentrations of inorganic carbon in an airlift-fluidized bed reactor.

    PubMed

    Tokutomi, Takaaki; Shibayama, Chizu; Soda, Satoshi; Ike, Michihiko

    2010-07-01

    A novel nitritation method based on the addition of inorganic carbon (IC) was verified using an airlift-fluidized bed reactor packed with sponge cubes. A continuous-treatment experiment demonstrated that the type of nitrification-nitrite or nitrate accumulation-could be controlled by the addition of different alkalinity sources (NaHCO(3) or NaOH, respectively). The maximum rate of ammonia oxidation at 30 degrees C was 2.47kg-N/(m(3) d), with nitrate formation of less than 0.5% of the converted ammonia. Nitrite accumulation of over 90% was maintained stably over 250 days at 30 degrees C and was achieved even at 19 degrees C. Qualitative and quantitative shifts of nitrifying bacteria in the biofilm were monitored by real-time PCR and T-RFLP analysis. Ammonia-oxidizing bacteria (AOB) were dominant but nitrite-oxidizing bacteria (NOB) were eliminated in the reactor when NaHCO(3) was used as the alkalinity source. From the kinetic data, we inferred that high IC concentrations drive stable nitritation by promoting a higher growth rate for AOB than for NOB. PMID:20554306

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

    SciTech Connect

    Michael John Vasbinder

    2006-12-12

    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}OO{sup 2+} and Rh(NH{sub 3}){sub 4}(H{sub 2}O)OO{sup 2+} 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(NH{sub 3}){sub 4}(H{sub 2}O)OO{sup 2+} 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 fitting the observed rate constants to the

  15. 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

  16. 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

  17. 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.

  18. 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.

  19. 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...

  20. Sulfate Saturated Hydrous Magmas Associated with Hydrothermal Gold Ores

    NASA Astrophysics Data System (ADS)

    Chambefort, I.; Dilles, J. H.; Kent, A. J.

    2007-12-01

    -ICP-MS. Yanacocha anhydrite, hosted by amphiboles, are enriched in FeO (up to 0.6 wt%) and present positive anomalies in Eu and SrO (up to 8000ppm in anhydrite blebs hosted by high Al amphibole of the sample RC6). Anhydrite hosted by clinopyroxene (CPx) and low Al amphibole present higher Ce2O3 content (up to 2000ppm in CPx). In comparison, hydrothermal anhydrite analyzed from El Salvador, Butte and Ajo ore deposits contain less SrO (~ 2000 ppm) and no FeO. Pinatubo anhydrite phenocrysts and inclusions from the 1991 Pinatubo dacite yield low FeO contents, except anhydrite included in amphibole. These data suggest FeO in anhydrite is a product of subsolidus diffusion from the host. The breakdown of abundant anhydrite crystals "stored" in the magma may source of SO2-rich hydrothermal fluids that produced the sulfur enrichment (>500 M Tonnes) observed the Yanacocha hydrothermal gold deposits. The two populations of amphibole are evidence of magma mixing in the Yanacocha magmatic rocks. A sulfate-saturated oxidized dacitic magma chamber resided at about 4 to 8 km depth and 800°C was periodically underplated or fed by hydrous sulfate-rich oxidized basaltic-andesite magma. The shape of the irregular anhydrite blebs suggest that these inclusions could have been trapped as an immiscible sulfate- phosphate rich melt, despite the fact that anhydrite normally has a liquidus temperature of 1450°C and the host amphiboles crystallized at no more than 1050°C based on experiments on andesites and dacites.

  1. 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

  2. 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

  3. 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

  4. 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.

  5. 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.

  6. 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. PMID:26384896

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

    PubMed

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

    2015-01-01

    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. PMID:26169260

  8. Oxygen isotopic composition of hydrous and anhydrous mantle peridotites

    NASA Astrophysics Data System (ADS)

    Chazot, Gilles; Lowry, David; Menzies, Martin; Mattey, David

    1997-01-01

    Oxygen isotope ratios, determined using the laser fluorination technique, are reported for minerals from anhydrous and hydrous (i.e., amphibole-bearing) spinel lherzolites from Yemen, as well as from hydrous spinel lherzolites and amphibole megacrysts from Nunivak Island, Alaska. Oxygen isotopic compositions of olivine vary from 5.1-5.4%c and of pyroxene from 5.5-6.0%c and no systematic difference exists between minerals in hydrous and anhydrous lherzolites. The oxygen isotopic composition of the amphibole in the peridotites and of the amphibole megacrysts is also very homogeneous and varies from δ 18O = 5.3-5.6%o. These results indicate that the metasomatic minerals in the lherzolites are in oxygen isotopic equilibrium with the peridotitic minerals. The only isotopic disequilibria are observed in minerals which have grown in melt-pockets formed by partial melting of amphibole. The homogeneity of the oxygen isotopic ratios of mantle minerals in this study indicate that the fluids circulating in the mantle and precipitating amphibole or mica had the same oxygen isotopic compositions as the mantle protolith or that the fluids had been buffered by the isotopic composition of the olivine, the most abundant mineral, during percolation through the peridotites.

  9. 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.

  10. 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.

  11. Velocity Crossover Between Hydrous and Anhydrous Forsterite at High Pressures

    SciTech Connect

    Mao, Z.; Jacobsen, S; Smyth, R; Holl, C; Frost, D; Duffy, T

    2010-01-01

    The elastic properties of hydrous forsterite, Mg{sub 2-x}SiO{sub 4}H{sub 2x}, are relevant to interpreting seismic velocity anomalies in the Earth's mantle. In this study, we used Brillouin scattering to determine the single-crystal elasticity of forsterite with 0.9(1) wt.% H{sub 2}O (x = 0.14) to 14 GPa. Aggregate bulk and shear moduli of hydrous forsterite increase with pressure at a greater rate than those of the corresponding anhydrous phase. Compared with anhydrous forsterite, we observe a 7% increase in the pressure derivative of the bulk modulus (K{prime}{sub S0} = 4.50(5)), and a 25% increase in the pressure derivative of the shear modulus (G{prime}{sub 0} = 1.75(5)) for forsterite with near maximum possible water content. Using our results, we calculated the compressional, V{sub P}, and shear, V{sub S}, velocities of forsterite as a function of pressure at 300 K. Whereas V{sub P} and V{sub S} of hydrous forsterite are 0.6% and 0.4% slower than those of anhydrous forsterite at ambient pressure, velocity crossovers at {approx} 3-4 GPa result in higher hydrous forsterite velocities at pressures corresponding to depths below {approx} 120 km. At the pressure of the 410-km discontinuity, V{sub P} and V{sub S} of hydrous forsterite exceed those of anhydrous forsterite by 1.1(1)% and 1.9(1)%, respectively. This implies that incorporation of water could decrease the magnitude of the velocity contrast at 410-km depth between forsterite and wadsleyite. Although the effects of hydration on temperature derivatives of the elastic moduli of forsterite and wadsleyite are not yet known, from the current data we estimate that the presence of {approx} 0.4 wt.% H{sub 2}O in forsterite (at 60 mol%) could lower the P and S velocity contrast at 410-km depth to 3.8(4)% and 4.8(6)%, respectively. At high pressures, hydration also decreases the V{sub P}/V{sub S} ratio of forsterite, and lowers the maximum P wave azimuthal anisotropy and S wave splitting of forsterite.

  12. 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.

  13. Calcium controls the assembly of the photosynthetic water-oxidizing complex: a cadmium(II) inorganic mutant of the Mn4Ca core

    PubMed Central

    Bartlett, John E; Baranov, Sergei V; Ananyev, Gennady M; Dismukes, G. Charles

    2007-01-01

    Perturbation of the catalytic inorganic core (Mn4Ca1OxCly) of the photosystem II-water-oxidizing complex (PSII-WOC) isolated from spinach is examined by substitution of Ca2+ with cadmium(II) during core assembly. Cd2+ inhibits the yield of reconstitution of O2-evolution activity, called photoactivation, starting from the free inorganic cofactors and the cofactor-depleted apo-WOC-PSII complex. Ca2+ affinity increases following photooxidation of the first Mn2+ to Mn3+ bound to the ‘high-affinity’ site. Ca2+ binding occurs in the dark and is the slowest overall step of photoactivation (IM1→IM1* step). Cd2+ competitively blocks the binding of Ca2+ to its functional site with 10- to 30-fold higher affinity, but does not influence the binding of Mn2+ to its high-affinity site. By contrast, even 10-fold higher concentrations of Cd2+ have no effect on O2-evolution activity in intact PSII-WOC. Paradoxically, Cd2+ both inhibits photoactivation yield, while accelerating the rate of photoassembly of active centres 10-fold relative to Ca2+. Cd2+ increases the kinetic stability of the photooxidized Mn3+ assembly intermediate(s) by twofold (mean lifetime for dark decay). The rate data provide evidence that Cd2+ binding following photooxidation of the first Mn3+, IM1→IM1*, causes three outcomes: (i) a longer intermediate lifetime that slows IM1 decay to IM0 by charge recombination, (ii) 10-fold higher probability of attaining the degrees of freedom (either or both cofactor and protein d.f.) needed to bind and photooxidize the remaining 3 Mn2+ that form the functional cluster, and (iii) increased lability of Cd2+ following Mn4 cluster assembly results in (re)exchange of Cd2+ by Ca2+ which restores active O2-evolving centres. Prior EPR spectroscopic data provide evidence for an oxo-bridged assembly intermediate, Mn3+(μ-O2−)Ca2+, for IM1*. We postulate an analogous inhibited intermediate with Cd2+ replacing Ca2+. PMID:17954439

  14. Calcium controls the assembly of the photosynthetic water-oxidizing complex: a cadmium(II) inorganic mutant of the Mn4Ca core.

    PubMed

    Bartlett, John E; Baranov, Sergei V; Ananyev, Gennady M; Dismukes, G Charles

    2008-03-27

    Perturbation of the catalytic inorganic core (Mn4Ca1OxCly) of the photosystem II-water-oxidizing complex (PSII-WOC) isolated from spinach is examined by substitution of Ca2+ with cadmium(II) during core assembly. Cd2+ inhibits the yield of reconstitution of O2-evolution activity, called photoactivation, starting from the free inorganic cofactors and the cofactor-depleted apo-WOC-PSII complex. Ca2+ affinity increases following photooxidation of the first Mn2+ to Mn3+ bound to the 'high-affinity' site. Ca2+ binding occurs in the dark and is the slowest overall step of photoactivation (IM1-->IM1* step). Cd2+ competitively blocks the binding of Ca2+ to its functional site with 10- to 30-fold higher affinity, but does not influence the binding of Mn2+ to its high-affinity site. By contrast, even 10-fold higher concentrations of Cd2+ have no effect on O2-evolution activity in intact PSII-WOC. Paradoxically, Cd2+ both inhibits photoactivation yield, while accelerating the rate of photoassembly of active centres 10-fold relative to Ca2+. Cd2+ increases the kinetic stability of the photooxidized Mn3+ assembly intermediate(s) by twofold (mean lifetime for dark decay). The rate data provide evidence that Cd2+ binding following photooxidation of the first Mn3+, IM1-->IM1*, causes three outcomes: (i) a longer intermediate lifetime that slows IM1 decay to IM0 by charge recombination, (ii) 10-fold higher probability of attaining the degrees of freedom (either or both cofactor and protein d.f.) needed to bind and photooxidize the remaining 3 Mn2+ that form the functional cluster, and (iii) increased lability of Cd2+ following Mn4 cluster assembly results in (re)exchange of Cd2+ by Ca2+ which restores active O2-evolving centres. Prior EPR spectroscopic data provide evidence for an oxo-bridged assembly intermediate, Mn3+(mu-O2(-))Ca2+, for IM1*. We postulate an analogous inhibited intermediate with Cd2+ replacing Ca2+. PMID:17954439

  15. 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

  16. 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.

  17. 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

  18. 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)

  19. Nitric oxide generated by nitrate reductase increases nitrogen uptake capacity by inducing lateral root formation and inorganic nitrogen uptake under partial nitrate nutrition in rice.

    PubMed

    Sun, Huwei; Li, Jiao; Song, Wenjing; Tao, Jinyuan; Huang, Shuangjie; Chen, Si; Hou, Mengmeng; Xu, Guohua; Zhang, Yali

    2015-05-01

    Increasing evidence shows that partial nitrate nutrition (PNN) can be attributed to improved plant growth and nitrogen-use efficiency (NUE) in rice. Nitric oxide (NO) is a signalling molecule involved in many physiological processes during plant development and nitrogen (N) assimilation. It remains unclear whether molecular NO improves NUE through PNN. Two rice cultivars (cvs Nanguang and Elio), with high and low NUE, respectively, were used in the analysis of NO production, nitrate reductase (NR) activity, lateral root (LR) density, and (15)N uptake under PNN, with or without NO production donor and inhibitors. PNN increased NO accumulation in cv. Nanguang possibly through the NIA2-dependent NR pathway. PNN-mediated NO increases contributed to LR initiation, (15)NH₄(+)/(15)NO₃(-) influx into the root, and levels of ammonium and nitrate transporters in cv. Nanguang but not cv. Elio. Further results revealed marked and specific induction of LR initiation and (15)NH₄(+)/(15)NO₃(-) influx into the roots of plants supplied with NH₄(+)+sodium nitroprusside (SNP) relative to those supplied with NH₄(+) alone, and considerable inhibition upon the application of cPTIO or tungstate (NR inhibitor) in addition to PNN, which is in agreement with the change in NO fluorescence in the two rice cultivars. The findings suggest that NO generated by the NR pathway plays a pivotal role in improving the N acquisition capacity by increasing LR initiation and the inorganic N uptake rate, which may represent a strategy for rice plants to adapt to a fluctuating nitrate supply and increase NUE. PMID:25784715

  20. 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). PMID:25716423

  1. 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

  2. Nitric oxide generated by nitrate reductase increases nitrogen uptake capacity by inducing lateral root formation and inorganic nitrogen uptake under partial nitrate nutrition in rice

    PubMed Central

    Sun, Huwei; Li, Jiao; Song, Wenjing; Tao, Jinyuan; Huang, Shuangjie; Chen, Si; Hou, Mengmeng; Xu, Guohua; Zhang, Yali

    2015-01-01

    Increasing evidence shows that partial nitrate nutrition (PNN) can be attributed to improved plant growth and nitrogen-use efficiency (NUE) in rice. Nitric oxide (NO) is a signalling molecule involved in many physiological processes during plant development and nitrogen (N) assimilation. It remains unclear whether molecular NO improves NUE through PNN. Two rice cultivars (cvs Nanguang and Elio), with high and low NUE, respectively, were used in the analysis of NO production, nitrate reductase (NR) activity, lateral root (LR) density, and 15N uptake under PNN, with or without NO production donor and inhibitors. PNN increased NO accumulation in cv. Nanguang possibly through the NIA2-dependent NR pathway. PNN-mediated NO increases contributed to LR initiation, 15NH4 +/15NO3 – influx into the root, and levels of ammonium and nitrate transporters in cv. Nanguang but not cv. Elio. Further results revealed marked and specific induction of LR initiation and 15NH4 +/15NO3 – influx into the roots of plants supplied with NH4 ++sodium nitroprusside (SNP) relative to those supplied with NH4 + alone, and considerable inhibition upon the application of cPTIO or tungstate (NR inhibitor) in addition to PNN, which is in agreement with the change in NO fluorescence in the two rice cultivars. The findings suggest that NO generated by the NR pathway plays a pivotal role in improving the N acquisition capacity by increasing LR initiation and the inorganic N uptake rate, which may represent a strategy for rice plants to adapt to a fluctuating nitrate supply and increase NUE. PMID:25784715

  3. Creep behavior of Fe-bearing olivine under hydrous conditions

    NASA Astrophysics Data System (ADS)

    Tasaka, Miki; Zimmerman, Mark E.; Kohlstedt, David L.

    2015-09-01

    To understand the effect of iron content on the creep behavior of olivine, (MgxFe(1 - x))2SiO4, under hydrous conditions, we have conducted tri-axial compressive creep experiments on samples of polycrystalline olivine with Mg contents of x = 0.53, 0.77, 0.90, and 1. Samples were deformed at stresses of 25 to 320 MPa, temperatures of 1050° to 1200°C, a confining pressure of 300 MPa, and a water fugacity of 300 MPa using a gas-medium high-pressure apparatus. Under hydrous conditions, our results yield the following expression for strain rate as a function of iron content for 0.53 ≤ x ≤ 0.90 in the dislocation creep regime: ɛ˙=ɛ˙0.90((1-x/0.1))1/2exp[226×1030.9-x/RT]. In this equation, the strain rate of San Carlos olivine, ɛ˙0.90, is a function of T, σ, and fH2O. As previously shown for anhydrous conditions, an increase in iron content directly increases creep rate. In addition, an increase in iron content increases hydrogen solubility and therefore indirectly increases creep rate. This flow law allows us to extrapolate our results to a wide range of mantle conditions, not only for Earth's mantle but also for the mantle of Mars.

  4. 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

  5. Shock effects on hydrous minerals and implications for carbonaceous meteorites

    NASA Technical Reports Server (NTRS)

    Lange, M. A.; Ahrens, T. J.; Lambert, P.

    1985-01-01

    The effect of shock loading over the pressure range of 29-59 GPa on the shock-recovered specimens of antigorite serpentine, Mg3Si2O5(OH)4, were investigated employing infrared (IR) spectroscopy, thermogravimetric analysis, and optical and scanning electron microscopy. With increasing shock pressure, there was an increase in H2O IR absorption peaks at the expense of OH peaks, while the changes in SiO bond vibration modes were identical to those seen for other, nonhydrous minerals. Thermogravimetric results on vented assembly samples showed linear relationships between the shock pressure and both the length of dehydration interval and the effective activation energy for releasing post-shock structural water. Optical and scanning electron microscopy revealed gas bubbles, which appeared to be injected into zones of partial melting, and vesicular dark veins distributed throughout the shocked samples. It is suggested that shock loading of hydrous minerals would release and redistribute free water in the regoliths of carbonaceous chondrite parent bodies, giving rise to observed hydrous alterations.

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

    NASA Astrophysics Data System (ADS)

    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.

    2014-03-01

    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.

  7. Uranium oxidation: Characterization of oxides formed by reaction with water by infrared and sorption analyses

    NASA Astrophysics Data System (ADS)

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

    1984-04-01

    Three different uranium oxide samples have been characterized with respect to the different preparation techniques. The 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. Inert gas sorption analyses and diffuse reflectance infrared studies combined with electron microscopy prove valuable in defining the chemistry and morphology of the oxidic products and hydrated intermediates.

  8. 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.

  9. 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

  10. 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

  11. 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.

  12. 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

  13. Hydrous alteration of amorphous silicate smokes - First results

    NASA Technical Reports Server (NTRS)

    Nuth, J. A.; Donn, B.; Deseife, R.; Donn, A.; Nelson, R.

    1986-01-01

    Results of the initial studies of the hydrous alteration of amorphous Mg-SiO smokes indicate that, although these materials readily adsorb water, the silicate structure is much more stable at 360 K than expected. Drastic changes in the relative absorption strengths of the 10- and 20-micron 'silicate' features that appear quite rapidly at 750 K were observed; these observations might have important implications for the interpretation of cometary dust spectra. Observations of the development of 3.4-3.5 micron features possibly due to hydrocarbons in the spectra of processed Mg-SiO smokes have raised the exciting possibility that these amorphous condensates could act as Fischer-Tropsch type catalysts to produce hydrocarbons in the primitive solar nebula.

  14. Radiative Heat Transfer in a Hydrous Transition Zone

    NASA Astrophysics Data System (ADS)

    Thomas, S.; Bina, C. R.; Jacobsen, S. D.; Goncharov, A. F.

    2012-12-01

    The structure and dynamics of Earth's interior depend crucially upon heat flow and thus upon the thermal conductivity of its constituents. The bulk thermal conductivity has two components: lattice conductivity (klat) and radiative conductivity (krad) [1,2]. Whereas lattice conductivity is governed by phonon propagation, radiative conductivity arises from heat transport by emission and absorption of photons. The latter, therefore, can be indirectly measured by analyzing the visible and infrared (VIS-IR) regions of a material's optical absorption spectrum. Thermal conductivity in the mantle is controlled by temperature, pressure, the electronic structure and concentration of transition metal ions (such as iron), and the water content of the material [1,3]. The radiative component has generally been assumed to be negligible, as most ferromagnesian minerals become opaque in the VIS-IR range at high pressures due to intensification and red-shift of electronic charge-transfer bands [4, 5]. However, more recent studies have suggested that mantle minerals may, in fact, remain relatively transparent at high pressures, thereby allowing for a potentially significant contribution to thermal conductivity from the radiative component [6]. We measured optical absorbance spectra of hydrous wadsleyite and hydrous ringwoodite at simultaneous high-pressure and high-temperature conditions up to 26 GPa and 823 K in order to determine their radiative conductivities and to study the potential influence of hydration in the transition zone on thermal conductivity of the mantle. We report radiative thermal conductivities of 1.5 ± 0.2 Wm-1K-1 for hydrous wadsleyite and 1.2 ± 0.1 Wm-1K-1 for hydrous ringwoodite at transition zone conditions. The analytically derived radiative thermal conductivities of anhydrous wadsleyite and ringwoodite are 2.1 ± 0.2 Wm-1K-1 and 1.6 ± 0.2 Wm-1K-1, respectively. Our results imply that a water content of ~1 wt% H2O lowers the thermal radiative conductivity

  15. 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

  16. 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

  17. 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.

  18. Toxicity of inorganic nanomaterials in biomedical imaging.

    PubMed

    Li, Jinxia; Chang, Xueling; Chen, Xiaoxia; Gu, Zhanjun; Zhao, Feng; Chai, Zhifang; Zhao, Yuliang

    2014-01-01

    Inorganic nanoparticles have shown promising potentials as novel biomedical imaging agents with high sensitivity, high spatial and temporal resolution. To translate the laboratory innovations into clinical applications, their potential toxicities are highly concerned and have to be evaluated comprehensively both in vitro and in vivo before their clinical applications. In this review, we first summarized the in vivo and in vitro toxicities of the representative inorganic nanoparticles used in biomedical imagings. Then we further discuss the origin of nanotoxicity of inorganic nanomaterials, including ROS generation and oxidative stress, chemical instability, chemical composition, the surface modification, dissolution of nanoparticles to release excess free ions of metals, metal redox state, and left-over chemicals from synthesis, etc. We intend to provide the readers a better understanding of the toxicology aspects of inorganic nanomaterials and knowledge for achieving optimized designs of safer inorganic nanomaterials for clinical applications. PMID:24389087

  19. A strongly hydrated microclast in the Rumuruti chondrite NWA 6828: Implications for the distribution of hydrous material in the solar system

    NASA Astrophysics Data System (ADS)

    Greshake, Ansgar

    2014-05-01

    Hydrous carbonaceous microclasts are by far the most abundant foreign fragments in stony meteorites and mostly resemble CI1-, CM2-, or CR2-like material. Their occurrence is of great importance for understanding the distribution and migration of water-bearing volatile-rich matter in the solar system. This paper reports the first finding of a strongly hydrated microclast in a Rumuruti chondrite. The R3-6 chondrite Northwest Africa 6828 contains a 420 × 325 μm sized angular foreign fragment exhibiting sharp boundaries to the surrounding R-type matrix. The clast is dominantly composed of magnetite, pyrrhotite, rare Ca-carbonate, and very rare Mg-rich olivine set in an abundant fine-grained phyllosilicate-rich matrix. Phyllosilicates are serpentine and saponite. One region of the clast is dominated by forsteritic olivine (Fa<2) supported by a network of interstitial Ca-carbonate. The clast is crosscut by Ca-carbonate-filled veins and lacks any chondrules, calcium-aluminum-rich inclusions, or their respective pseudomorphs. The hydrous clast contains also a single grain of the very rare phosphide andreyivanovite. Comparison with CI1, CM2, and CR2 chondrites as well as with the ungrouped C2 chondrite Tagish Lake shows no positive match with any of these types of meteorites. The clast may, thus, either represent a fragment of an unsampled lithology of the hydrous carbonaceous chondrite parent asteroids or constitute a sample from an as yet unknown parent body, maybe even a comet. Rumuruti chondrites are a unique group of highly oxidized meteorites that probably accreted at a heliocentric distance >1 AU between the formation regions of ordinary and carbonaceous chondrites. The occurrence of a hydrous microclast in an R chondrite attests to the presence of such material also in this region at least at some point in time and documents the wide distribution of water-bearing (possibly zodiacal cloud) material in the solar system.

  20. 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...

  1. 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

  2. Implication on Aqueous History of Mars as Revealed by Hydrous Minerals in Southwest Melas Chasma

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Glotch, T. D.

    2014-07-01

    We made new detections of hydrous minerals in southwest Melas Chasma including poly- and mono-hydrated sulfates, jarosite, and Fe/Mg smectites, and explored their possible formation mechanisms and implications on martian aqueous history.

  3. Density of Hydrous Ultramafic Silicate Melt under the Earth's Deep Upper Mantle Conditions

    NASA Astrophysics Data System (ADS)

    Jing, Z.; Matsukage, K. N.; Karato, S.

    2005-12-01

    between hydrous melts and the surrounding solids at 410 km were determined for different water content, temperature, and partial molar volume of water. Results showed that the critical water content is ~6wt% for T=1800K and V̅H2O=8cm3/mol, although the uncertainties are still large. We recognize, however, that these initial results likely underestimated the melt density in Earth's mantle. The low-pressure data indicate that oxygen fugacity has important effects on melt density (e.g., Kress & Carmichael, 1991). In our experiments, we used a rhenium capsule to minimize the chemical reaction, which defines a relatively high oxygen fugacity. At lower oxygen fugacities, the oxidation state of iron is likely different, which will increase the density of melts. Calculations showed that at room pressure the density difference between sample buffered by Re-ReO2 and by Mo-MoO2 is ~0.5-2%, which is important to determine the conditions for density crossover. We will report on new results on the influence of oxygen fugacity on melt density which will provide a better estimate for the conditions for density cross-over.

  4. 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

  5. Deformation of olivine in torsion under hydrous conditions

    NASA Astrophysics Data System (ADS)

    Demouchy, Sylvie; Tommasi, Andréa; Barou, Fabrice; Mainprice, David; Cordier, Patrick

    2012-08-01

    We performed torsional deformation experiments on pre-hydrated fine-grained olivine aggregates using an innovative experimental assembly to investigate water weakening in mantle rocks at high shear strains. San Carlos olivine powder was cold-pressed and then hot-pressed under hydrous conditions, producing aggregates with average grain sizes of 7 or 15 μm. Deformation experiments were performed in a high-resolution gas-medium apparatus equipped with a torsional actuator, under a confining pressure of 300 MPa, a temperature of 1200 °C, and constant shear strain rates ranging from 8 × 10-5 to 1.4 × 10-4 s-1. Maximum shear stresses range from 150 to 195 MPa. These values are 30% lower relative to those determined in previous torsion experiments on dry, fined-grained dunites under similar conditions. Textures and microstructures of the starting and deformed specimens were characterized by scanning and transmission electron microscopy. All deformed aggregates exhibit a shape-preferred orientation marking a foliation and lineation, as well as a reduction in mean grain size from 15 μm down to 3-4 μm due to dynamic recrystallization. Olivine crystallographic fabrics developed rapidly (γ < 0.1), but their strength, characterized by the J-index, is low compared to naturally deformed peridotites or to polycrystalline olivine deformed at similar finite shear strains under dry conditions. The crystallographic fabrics are consistent with deformation by a dislocation accommodated creep mechanism with activation of multiple {0 k l}[1 0 0] systems, among which the (0 1 0)[1 0 0] slip system is dominant, and minor participation of the (0 1 0)[0 0 1] slip system. Transmission electron microscopy confirmed the occurrence of dislocations with [1 0 0] and [0 0 1] Burgers vectors in most grains. Analysis of unpolarized infrared spectra indicates that hydrogen concentration in the olivine lattice is below the saturation level of 18 ppm wt H2O, which is similar to those typically

  6. 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

  7. In situ identification and analysis of automotive paint pigments using line segment excitation Raman spectroscopy: I. Inorganic topcoat pigments.

    PubMed

    Suzuki, E M; Carrabba, M

    2001-09-01

    Several applications of Raman spectroscopy in the forensic sciences have recently been demonstrated, but few have involved the analysis of paints. Undoubtedly, this is a reflection of the sample degradation problems often encountered when a visible or near-infrared laser is focused on a light-absorbing matrix. In this study, a dispersive CCD Raman spectrometer (785 nm) was used in a configuration which collected scattered light from an excitation region 3 mm long and 80 microm wide, instead of from a focused spot. Sample degradation was not observed, and Raman spectra of automotive paints of all colors were readily obtained. Most of the paints analyzed were U.S. automobile original finishes (1974 to 1989) from the Reference Collection of Automotive Paints, and the inorganic pigments examined were those which had been identified previously by infrared spectroscopy in finishes from this collection. Prominent peaks of rutile were observed in Raman spectra of light-colored nonmetallic finishes for both monocoats and basecoat/clearcoat systems, and the rutile peaks are readily distinguished from those of anatase. The lead chromates (Chrome Yellow, Molybdate Orange, and silica-encapsulated versions of the two) are the strongest Raman scatterers among the pigments examined, and Chrome Yellow was identified by Raman spectroscopy in several yellow and orange nonmetallic monocoats for which infrared absorptions of this pigment were not observed. Raman spectroscopy also provides an unequivocal means to distinguish Chrome Yellow from Molybdate Orange. This is particularly helpful for the analysis of paints containing light pigment loads or encapsulated pigments since the two formulations cannot be differentiated by infrared spectroscopy in such cases. The iron-containing pigments, ferric oxide, hydrous ferric oxide, and Prussian Blue, are relatively weak Raman scatterers, but peaks of hydrous ferric oxide and Prussian Blue were observed in spectra of paints containing heavy

  8. 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.

  9. 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

  10. Stress-Induced Proton Disorder in Hydrous Ringwoodite

    NASA Astrophysics Data System (ADS)

    Koch-Müller, M.; Rhede, D.; Mrosko, M.; Speziale, S.; Schade, U.

    2008-12-01

    The system (Fe,Mg)2SiO4 with its modifications olivine, wadsleyite and ringwoodite has been the subject of numerous studies in the past to determine the maximum solubility of hydrogen in their structures (e.g., Kudoh et al., 2000). Nowadays experimental work is focused on the effect of the water content on the physical, structural and thermodynamic properties. Camorro Perez et al. (2006) studied hydrous (1 and 1.7 wt % water) Mg-ringwoodite by in-situ high-pressure IR spectroscopy up to 30 GPa using Neon as pressure medium and reported a second-order phase transition at pressures of about 25 GPa with sudden disappearance of the prominent OH band centred at 3150 cm-1. To study this phenomenon in the whole system (Fe,Mg)2SiO4 we synthesized Fe- rich hydrated ringwoodite of different compositions ranging from xFe = 1.0 to xFe = 0.40. The samples were investigated by electron microprobe, secondary ion mass spectrometry (SIMS), conventional and synchrotron FTIR spectroscopy at ambient condition and to 30 GPa in situ in the diamond anvil cell (DAC). Water determination using SIMS in combination with IR spectroscopy yielded concentrations ranging from 0.6 wt % for the Fe- endmember to 2.5 wt % for the Mg-richest sample. Several DAC experiments were performed with ringwoodite of compositions xFe = 0.4, 0.5 and 0.6 in a Megabar diamond anvil cell. We performed the high pressure measurements in different pressure transmitting environments. In the experiments performed using CsI powder, or cryogenically loaded liquid Argon, between 10 and 12 GPa, the prominent OH-stretching suddenly disappears, and the lattice vibrations show discontinuities, independent of composition. In another set of experiments cryogenically loaded liquid Argon was annealed for one hour at 8.6 GPa to 120° C before further increasing the pressure to ensure more hydrostatic conditions (Wittlinger et al. 1997). In these experiments the OH stretching vibrations as well as lattice vibrations could be

  11. 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

  12. 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.

  13. Distribution of hydrous minerals in the subduction system beneath Mexico

    NASA Astrophysics Data System (ADS)

    Kim, YoungHee; Clayton, Robert W.; Jackson, Jennifer M.

    2012-08-01

    Teleseismic converted phases are used to probe the composition of the downgoing oceanic crust as a function of depth along the Cocos slab in central and southern Mexico. Previously, modeling of the receiver function (RF) conversion amplitude of the flat Cocos slab beneath central Mexico at 45 km depth revealed a thin low-velocity upper oceanic crust of a thickness of 4±1 km, which has much lower seismic velocities (∼20-30% reduction in shear wave velocities) than (normal) lower crust. High Vp/Vs ratio (∼2.0) also suggested a large concentration of hydrous minerals such as talc in combination of high pore-fluid pressure in the horizontal segment. We extend this previous effort to examine seismic properties of both the steeply subducting Cocos oceanic crust beneath the Trans-Mexican Volcanic Belt (TMVB) in central Mexico and the shallowly dipping crust beneath southern Mexico. Inverted seismic velocities using the converted amplitudes at the top and bottom of the dipping oceanic crust are compared with experimentally constrained seismic velocities of candidate mineral phases in a range of likely pressures and temperatures. The composition of the oceanic crust downdip in the steep part of slab beneath the TMVB includes the minerals such as lawsonite and zoisite at 60-100 km depth, and the eclogitization occurs around 100 km depth. This is related to arc volcanism in the TMVB directly above the slab as well as the slab rollback. In contrast, the dominant mineral phase in the upper oceanic crust of southern Mexico beneath the Isthmus of Tehauntepec is amphibole on top of unaltered gabbroic oceanic crust. The difference in mineral assemblages of the subducted oceanic crust may help explain the difference in slab geometries between central and southern Mexico.

  14. 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

  15. Organic/Inorganic Composite Latexes: The Marriage of Emulsion Polymerization and Inorganic Chemistry

    NASA Astrophysics Data System (ADS)

    Bourgeat-Lami, Elodie; Lansalot, Muriel

    This review article describes recent advances in the synthesis and properties of waterborne organic/inorganic colloids elaborated through conventional emulsion polymerization, a well-established technology. These materials can be defined as aqueous suspensions of composite latex particles made up of organic and inorganic domains organized into well-defined core-shell, multinuclear, raspberry-like, multipod-like, or armored morphologies. Particular emphasis is placed on the synthetic strategies for fabrication of these colloidal materials. Two main approaches are described: the polymerization of organic monomers in the presence of preformed inorganic particles, and the reverse approach by which inorganic materials are synthesized in the presence of preformed polymer latexes. The list of examples provided in this review is by no means exhaustive but rather intends to give an overview of synthetic methods for selected inorganic compounds (e.g., silica, iron oxide, pigments, clays, quantum dots, and metals), and briefly reports on potential applications of the resulting materials.

  16. 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

  17. 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

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. Effect of Hydrous Mantle on a Coupled Core-Mantle Evolution

    NASA Astrophysics Data System (ADS)

    Nakagawa, T.; Iwamori, H.

    2014-12-01

    The water in the mantle is also important for dynamics, evolution, composition and structure of deep Earth's interior [e.g. Karato, 2011]. However, the hydrous mantle was not assumed for thermo-chemical evolution model in numerical mantle convection simulations [e.g. Nakagawa and Tackley, 2014]. To assess the effect of hydrous mantle in thermo-chemical evolution of deep Earth's interior, we develop a coupled core-mantle evolution model including water transportation system based on Iwamori [1998; 2004]. The important ingredient of this model is the rheological property of hydrous mantle and dehydration processes. Here we assume this taken from deformation experiments on hydrous olivine [e.g. Mei and Kohlsteadt, 2000; Korenaga and Karato, 2008; Fei et al., 2013], which ranges from weak to extremely strong viscosity dependence due to the water content. We also assume the reduction of solidus temperature of mantle minerals based on Katz et al. [2003]. Preliminary results suggested that the best-fit scenario of thermo-chemical evolution of Earth's mantle and core could be found in the weak rheological dependence due to the water content. In the successful model, the lower mantle would be close to water-saturated situation less than 1.0 Gyrs from initial condition assuming the completely dry mantle. In the presentation, we will also discuss the possibility on hydrous basalt in the lowermost mantle and geochemical evolution in the deep mantle.

  3. Solubility of Au in Cl- and S-bearing hydrous silicate melts

    NASA Astrophysics Data System (ADS)

    Botcharnikov, R. E.; Linnen, R. L.; Holtz, F.

    2010-04-01

    The solubility of Au in Cl- and S-bearing hydrous rhyodacitic and andesitic melts has been experimentally investigated at 1050 °C, 200 MPa and log fO 2 close to the Ni/NiO solid oxygen buffer (NNO). The concentrations of Au in the experimental glasses have been determined using Laser Ablation ICP-MS (LA) with special efforts to avoid incorporation of Au micronuggets in the analysis. It is concluded that metal micronuggets are an experimental artefact and produced by Au partitioning into the fluids during heating with consequent precipitation on fluid dissolution in the melting glass powder. Hence, the micronuggets do not represent quench phases and must be excluded from the analysis. The micro-analytical data obtained by LA show that Au concentrations vary from ˜0.2 to ˜2.5 ppm by weight, generally consistent with the literature data for other melt compositions. The measured Au concentrations increase with increasing amounts of Cl and S dissolved in the silicate melt and show a correlation with the apparent activities of Cl and S in the system. The apparent activities of Cl and S are defined by the simplified linear relationship between volatile concentrations in the melt and activity of volatiles. The maximum activity ( a∗ = 1) is assumed to be reached at the saturation of the systems in respect of Cl-rich brine or FeS liquid for Cl and S, respectively. The dependence of Au solubility on the concentrations/activities of Cl and S at the fixed redox conditions shows that Au may form not only oxide- but also Cl- and S-bearing complexes in silicate melts. Furthermore, it indicates that exsolution of S and Cl from the melt by degassing/segregation/crystallization processes may lead to mobilization and extraction of Au into the fluid, liquid and/or mineral phase(s).

  4. 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

  5. Optical Absorption Spectra of Hydrous Wadsleyite to 32 GPa

    NASA Astrophysics Data System (ADS)

    Thomas, S.; Goncharov, A. F.; Jacobsen, S. D.; Bina, C. R.; Frost, D. J.

    2009-05-01

    Optical absorption spectra of high-pressure minerals can be used as indirect tools to calculate radiative conductivity of the Earth's interior [e.g., 1]. Recent high-pressure studies show that e.g. ringwoodite, γ-(Mg,Fe)2SiO4, does not become opaque in the near infrared and visible region, as previously assumed, but remains transparent to 21.5 GPa [2]. Therefore, it has been concluded that radiative heat transfer does not necessarily become blocked at high pressures of the mantle and ferromagnesian minerals actually could contribute to the heat flow in the Earth's interior [2]. In this study we use gem-quality single-crystals of hydrous Fe-bearing wadsleyite, β-(Mg,Fe)2SiO4, that were synthesized at 18 GPa and 1400 °C in a multianvil apparatus. Crystals were analyzed by Mössbauer and Raman spectroscopy, electron microprobe analysis and single-crystal X-ray diffraction. For absorption measurements a double-polished 50 μm sized single-crystal of wadsleyite was loaded in a diamond-anvil cell with neon as pressure medium. Optical absorption spectra were recorded at ambient conditions as well as up to 32 GPa from 400 to 50000 cm-1. At ambient pressure the absorption spectrum reveals two broad bands at - 10000 cm-1 and -15000 cm-1, and an absorption edge in the visible-ultraviolet range. With increasing pressure the absorption spectrum changes, both bands continuously shift to higher frequencies as has been observed for ringwoodite [2], but is contrary to earlier presumptions for wadsleyite [3]. Here, we will discuss band assignment along with the influence of iron, compare our results to previous absorption studies of mantle materials [2], and analyze possible implications for radiative conductivity of the transition zone. References: [1] Goncharov et al. (2008), McGraw Yearbook Sci. Tech., 242-245. [2] Keppler & Smyth (2005), Am. Mineral., 90 1209-1212. [3] Ross (1997), Phys. Chem. Earth, 22 113-118.

  6. Distribution of Hydrous Minerals in the Subduction System beneath Mexico

    NASA Astrophysics Data System (ADS)

    Kim, Y.; Clayton, R. W.; Jackson, J. M.; Asimow, P. D.

    2011-12-01

    Teleseismic converted phases are used to estimate the mineralogy of subducting material as a function of depth along the Cocos slab in central and southern Mexico. Modeling of the receiver function (RF) conversion amplitudes of the horizontal slab, south of the Trans-Mexican Volcanic Belt (TMVB) in central Mexico, reveals a thin low-velocity zone between the Cocos plate and the continental crust that appears to absorb nearly all of the strain between the upper plate and the Cocos slab. Using Vp/Vs versus Vs in a range of likely pressures and temperatures for candidate mineral phases, this thin (~4 km thick) layer in the flat slab region of central Mexico is determined to be enriched with hydrous minerals such as talc over normal oceanic crustal compositions such as MORB-like gabbro. On the other hand, the mineralogy of the oceanic crust downdip in the steep part of the slab beneath the TMVB is enriched with lawsonite and zoisite, which then transitions into gabbroic and eclogitic assemblages at 100 km. This supports arc volcanism in the TMVB directly above the slab as well as the slab rollback. In contrast, the dominant mineral phase in the upper oceanic crust of southern Mexico beneath the Isthmus of Tehauntepec is amphibole on top of unaltered gabbroic oceanic crust. Based on the P-T curves for equilibria involving talc derived from available thermodynamic data, the generation of talc from the basaltic lithology of the oceanic crust subducting from the trench side is nearly impossible. We therefore propose that the talc-rich layer on top of the subducting plate is generated from the mantle wedge side during the slab flattening process coupled with trench rollback. The talc-rich rocks at the slab interface can be formed in the mantle by the addition of silica transported by rising fluids via the dehydration reaction from the subducting oceanic crust and by mechanical mixing of mantle and siliceous rocks. Thus, it appears that the thin low-strength layer, which

  7. 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.

  8. Method for plating with metal oxides

    DOEpatents

    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.

  9. 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

  10. Mesostructured tin oxide as sensitive material for C(2)H(5)OH sensor.

    PubMed

    Wang, Yu-De; Ma, Chun-Lai; Wu, Xing-Hui; Sun, Xiao-Dan; Li, Heng-De

    2002-07-01

    Mesostructured tin oxide with high specific surface area was synthesized using cationic surfactant (cetyltrimethylammonium bromide, CTAB: CH(3)(CH(2))(15)N(+)(CH(3))(3)Br(-)) as the organic template and hydrous tin chloride (SnCl(4).5H(2)O) and NH(4)OH as the inorganic precursors under acidic conditions at ambient temperature. Thermogravimetric analysis (TGA), Fourier transformed infrared (FTIR), X-ray diffraction analysis (XRD), X-ray photoelectron spectrum (XPS) and N(2)-sorption isotherms were used to characterize the mesostructured tin oxide that was formed at room temperature as well as calcined at different temperature. The surface area of mesostructured tin oxide calcined at 400 degrees C is 136 m(2) g(-1). The indirect heating sensor using this material as sensitive body was fabricated on an alumna tube with Au electrodes and platinum wires. Electrical and sensing properties of such a sensor were investigated. It was found that the mesostructured tin oxide with high surface area had higher sensitivity to C(2)H(5)OH and selectivity to gasoline than commercial sample of polycrystalline tin(IV) oxide. PMID:18968691

  11. 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

  12. 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. PMID:27329791

  13. 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.

  14. 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. PMID:25965632

  15. 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

  16. 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.

  17. High performance nickel-palladium nanocatalyst for hydrogen generation from alkaline hydrous hydrazine at room temperature

    NASA Astrophysics Data System (ADS)

    Bhattacharjee, Debaleena; Mandal, Kaustab; Dasgupta, Subrata

    2015-08-01

    Room temperature synthesized highly active bimetallic Ni60Pd40 nanocatalyst with large surface area (150 m2g-1) exerts 100% selectivity towards hydrogen generation (3 equivalents of gas in 60 min) from hydrous hydrazine under alkaline and ambient reaction conditions. This low noble metal content catalyst offers a new prospect for on-board hydrogen production system.

  18. 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)

  19. 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

  20. The role of Nrf2/Keap1 signaling in inorganic mercury induced oxidative stress in the liver of large yellow croaker Pseudosciaena crocea.

    PubMed

    Zeng, Lin; Zheng, Jia-Lang; Wang, Yong-Hong; Xu, Mei-Ying; Zhu, Ai-Yi; Wu, Chang-Wen

    2016-10-01

    The aim of the present study was to evaluate the effects of acute inorganic Hg exposure (0, 32 and 64μgHgL(-1)) on lipid peroxidation, activities and gene expression of antioxidant enzymes (Cu/Zn-SOD, CAT, GPx, GR and GST), and mRNA levels of the Keap1-Nrf2 signaling molecules at different exposure times (6h, 12h, 24h, 48h, and 96h) in the liver of large yellow croaker Pseudosciaena crocea. The results showed that lipid peroxidation was sharply reduced by 32μg Hg L(-1) during 6-12h before returning to control levels. Similarly, lipid peroxidation was significantly reduced during 6-12h followed by a sharp increase towards the end of the exposure in the 64μgHgL(-1) group. There was a negative relationship between lipid peroxidation and antioxidant enzyme activities, and positive relationship between activities and gene expression of antioxidant enzymes, suggesting that the changes at a molecular level may underlie enzymatic level and accordingly affect hepatic lipid peroxidation. Obtained results also showed a coordinated transcriptional regulation of antioxidant genes, suggesting that Nrf2 is required for the protracted induction of these genes. Furthermore, a negative relationship between the mRNA levels of Nrf2 and Keap1 indicated that Keap1 may play an important role in switching off the Nrf2 response. In conclusion, this is the first study to elucidate effects of waterborne Hg on antioxidant system in large yellow croaker through the Keap1-Nrf2 pathway, which will aid our understanding of the molecular mechanisms of waterborne heavy metal on antioxidant responses in fish. PMID:27362492

  1. 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.

  2. 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.

  3. 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

  4. Crystallization and functionality of inorganic materials

    SciTech Connect

    Xue, Dongfeng; Li, Keyan; Liu, Jun; Sun, Congting; Chen, Kunfeng

    2012-10-15

    In this article, we briefly summarized our recent work on the studies of crystallization and functionality of inorganic materials. On the basis of the chemical bonding theory of single crystal growth, we can quantitatively simulate Cu{sub 2}O crystallization processes in solution system. We also kinetically controlled Cu{sub 2}O crystallization process in the reduction solution route. Lithium ion battery and supercapacitor performances of some oxides such as Co{sub 3}O{sub 4} and MnO{sub 2} were shown to elucidate the important effect of crystallization on functionality of inorganic materials. This work encourages us to create novel functionalities through the study of crystallization of inorganic materials, which warrants more chances in the field of functional materials.

  5. 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

  6. 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

  7. 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.

  8. 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

  9. Enhanced rate performance of mesoporous Co(3)O(4) nanosheet supercapacitor electrodes by hydrous RuO(2) nanoparticle decoration.

    PubMed

    Rakhi, R B; Chen, Wei; Hedhili, M N; Cha, Dongkyu; Alshareef, H N

    2014-03-26

    Mesoporous cobalt oxide (Co3O4) nanosheet electrode arrays are directly grown over flexible carbon paper substrates using an economical and scalable two-step process for supercapacitor applications. The interconnected nanosheet arrays form a three-dimensional network with exceptional supercapacitor performance in standard two electrode configuration. Dramatic improvement in the rate capacity of the Co3O4 nanosheets is achieved by electrodeposition of nanocrystalline, hydrous RuO2 nanoparticles dispersed on the Co3O4 nanosheets. An optimum RuO2 electrodeposition time is found to result in the best supercapacitor performance, where the controlled morphology of the electrode provides a balance between good conductivity and efficient electrolyte access to the RuO2 nanoparticles. An excellent specific capacitance of 905 F/g at 1 A/g is obtained, and a nearly constant rate performance of 78% is achieved at current density ranging from 1 to 40 A/g. The sample could retain more than 96% of its maximum capacitance even after 5000 continuous charge-discharge cycles at a constant high current density of 10 A/g. Thicker RuO2 coating, while maintaining good conductivity, results in agglomeration, decreasing electrolyte access to active material and hence the capacitive performance. PMID:24580967

  10. 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

  11. 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.

  12. Hydrogen site analysis of hydrous ringwoodite in mantle transition zone by pulsed neutron diffraction

    NASA Astrophysics Data System (ADS)

    Purevjav, Narangoo; Okuchi, Takuo; Tomioka, Naotaka; Abe, Jun; Harjo, Stefanus

    2014-10-01

    Hydrogen site positions and occupancies in the crystal structure of synthetic hydrous ringwoodite have been determined for the first time by high-resolution neutron powder diffraction conducted at the pulsed neutron source at Japan Proton Accelerator Research Complex (J-PARC). It is demonstrated that hydrogen exchanges not only with Mg or Fe but also with Si cations to form hydroxyl and hydrogen bonding, both within the relevant octahedra or tetrahedra created by their surrounding oxygen anions. The hydrated octahedra shrink, whereas the hydrated tetrahedra expand. The occurrence of simultaneous hydration of octahedra and tetraheda is thus unambiguously confirmed, whereby the latter plays an especially unique role in reducing seismic velocity and for enhancing the electrical conductivity of ringwoodite at high pressures and temperatures. These results provide distinctive implications for discussing the physical properties of hydrous ringwoodite occurring in the mantle transition zone and evaluating the actual water content in the zone.

  13. 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

  14. 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

  15. 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.…

  16. Dynamics, crustal thicknesses, seismic anomalies, and electrical conductivities in dry and hydrous ridge-centered plumes

    NASA Astrophysics Data System (ADS)

    Ruedas, Thomas

    2006-04-01

    3D convection and melting models for ridge-centered plumes in the upper 410 km of the mantle have been computed for dry and hydrous mantles, taking into account the effects of water on melting and viscosity. Dry and hydrous models have fundamentally different flow and melting styles in the melting regime: in the dry model, active upwelling occurs to shallow depth and results in a very thick, narrow plume-generated crust, whereas dehydration stiffening in the hydrous models enforces passive upwelling in much of the melting region and causes the plume crust to be much less thick, but broader in along-ridge direction. The output of the numerical models, i.e. temperature, melting degree, water content, and porosity, is used to compute synthetic models of seismic velocity anomalies and electrical conductivity. For this purpose, combinations of theoretical and empirical relations with recent experimental data are developped. The models predict that the seismic velocity anomaly of the deep, unmolten plume stem is mostly thermal in both water-bearing and water-free plumes, but that the two velocity minima in the anomaly in the melting zone of the plume are much more clearly distinguishable in a water-bearing plume. If one assumes a contribution to the electrical conductivity of hydrous mantle from free protons, and if the water reservoir features large-scale contiguity, one would also expect a strong high-conductivity anomaly in the plume stem which should be visible to magnetotelluric observations. However, comparison with observations suggests that a simple free-proton model may not be applicable.

  17. Growth of Diamond from a Carbonaceous Hydrous Silicate Melt: An Experimental Study

    NASA Astrophysics Data System (ADS)

    Fagan, A. J.; Luth, R. W.

    2007-12-01

    Diamond was grown in a hydrous halide-bearing silicate system at pressures and temperatures near those at which natural peridotitic diamonds form (1000-1300° C, 5-7 GPa) in the Earth' s upper mantle. The mechanisms by which diamonds are made within the earth is still unresolved, and many authors have suggested possible media from which diamonds precipitate; examples include mantle carbonates, sulphides and silicates (1-3). To date, little work has been conducted on silicate melts and the effect of mantle catalysts on diamond formation. This study used a hydrous silicate melt (HSM) to attempt to precipitate diamond. The primary experimental system was MgO-SiO2-C-H2O, with subsystems to document the addition of alkali halides (KCl and NaCl). Previous studies have concluded that alkali halides have a catalytic effect on diamond formation reactions and observed halides in inclusions in natural diamonds. Diamond was successfully grown on seed crystals at temperatures of 1400-1500° C and pressures of 6-7 GPa, in 3-4 hours. No spontaneous nucleation of diamond was observed during these experiments. No diamond growth was observed in experiments at < 1400° C and 6 GPa to date. The addition of KCl to the HSM system allowed diamond to form 200° C lower than the previously published minimum temperature of over 1600° C (3). The effect of NaCl and other catalysts are still under investigation. The starting compositions contain ~ 20.6wt% structural H2O. At run conditions, a hydrous melt coexisted with olivine and orthropyroxene, with the halides either dissolved in the melt or forming a separate brine. This study demonstrates that hydrous silicate melts, especially containing alkali halides, are a viable medium for diamond growth in the Earth' s upper mantle. 1) Arima et al, 2002; 2) Gunn & Luth, 2006; 3) Pal' yanov et al, 2007

  18. Synthesis of porous inorganic hollow fibers without harmful solvents.

    PubMed

    Shukla, Sushumna; de Wit, Patrick; Luiten-Olieman, Mieke W J; Kappert, Emiel J; Nijmeijer, Arian; Benes, Nieck E

    2015-01-01

    A route for the fabrication of porous inorganic hollow fibers with high surface-area-to-volume ratio that avoids harmful solvents is presented. The approach is based on bio-ionic gelation of an aqueous mixture of inorganic particles and sodium alginate during wet spinning. In a subsequent thermal treatment, the bio-organic material is removed and the inorganic particles are sintered. The method is applicable to the fabrication of various inorganic fibers, including metals and ceramics. The route completely avoids the use of organic solvents, such as N-methyl-2-pyrrolidone, and additives associated with the currently used fiber fabrication methods. In addition, it inherently avoids the manifestation of so-called macro voids and allows the facile incorporation of additional metal oxides in the inorganic hollow fibers. PMID:25256812

  19. A crystallographic model for hydrous wadsleyite (Beta-Mg2SiO4)

    NASA Technical Reports Server (NTRS)

    Smyth, J. R.

    1994-01-01

    Wadsleyite (beta-Mg2SiO4) is believed to be the most abundant phase in the Earth between depths of 400 and about 525km. Because of the unusual crystal chemistry, Smyth suggested that this phase might be a significant host for hydrogen in the transition zone. Indeed, of the nominally anhydrous phases believed to make up the upper mantle and transition zone none has been reported with a greater H content than wadsleyite. Young et al, report the synthesis of hydrous, Fe-bearing wadsleyite with up to 60,000 H per 10(exp 6) Si. Using ionic constraints and maximal subgroup symmetry, a hypothetical, ordered model for hydrous wadsleyite has been created and examined. The model has formula Mg7Si4O14(OH)2, has space group Pmmb, has an ordered vacancy into one of two non-equivalent M2 sites, and contains two different H positions, one on each of the non-equivalent O1 sites. Electrostatic calculations indicate that hydration would relieve the underbonding of O1 as well as the overbonding of the bridging oxygen, O2, so that the hydrous phase may be more stable than the anhydrous phase. This model makes several predictions that may be of significance for the mechanisms and amounts of H that may be stored in the transition zone of the Earth, and by which the model may be tested experimentally.

  20. pH dependence of Fenton reagent generation and As(III) oxidation and removal by corrosion of zero valent iron in aerated water.

    PubMed

    Katsoyiannis, Ioannis A; Ruettimann, Thomas; Hug, Stephan J

    2008-10-01

    Corrosion of zerovalent iron (ZVI) in oxygen-containing water produces reactive intermediates that can oxidize various organic and inorganic compounds. We investigated the kinetics and mechanism of Fenton reagent generation and As(III) oxidation and removal by ZVI (0.1m2/g) from pH 3-11 in aerated water. Observed half-lives for the oxidation of initially 500 microg/L As(III) by 150 mg Fe(0)/L were 26-80 min at pH 3-9. At pH 11, no As(III) oxidation was observed during the first two hours. Dissolved Fe(III) reached 325, 140, and 6 microM at pH 3, 5, and 7. H2O2 concentrations peaked within 10 min at 1.2, 0.4, and < 0.1 microM at pH 3, 5, and 7, and then decreased to undetectable levels. Addition of 2,2'-bipyridine (1-3 mM), prevented Fe(II) oxidation by O2 and H2O2 and inhibited As(III)oxidation. 2-propanol (14 mM), scavenging OH-radicals, quenched the As(III) oxidation at pH 3, but had almost no effect at pH 5 and 7. Experimental data and kinetic modeling suggest that As(III) was oxidized mainly in solution by the Fenton reaction and removed by sorption on newly formed hydrous ferric oxides. OH-radials are the main oxidant for As(III) at low pH, whereas a more selective oxidant oxidizes As(III) at circumneutral pH. PMID:18939581

  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. 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

  3. 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.

  4. 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...

  5. 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

  6. 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

  7. The influence of hydrous phases on the microstructure and seismic properties of a hydrated mantle rock

    NASA Astrophysics Data System (ADS)

    Morales, Luiz F. G.; Mainprice, David; Boudier, Françoise

    2013-05-01

    To better understand the microstructural evolution of a “serpentinized” mantle rock and the influence of various hydrous phases on the seismic properties of the mantle wedge, we have conducted the detailed microstructural analyses of a sample of tremolite-chlorite-antigorite schist collected from the Moses Rock dike (central part of the Colorado Plateau). We performed differential effective media (DEM) modelling to study the effect of three hydrous phases forming two-phase aggregates with olivine, considering the crystallographic preferred orientation (CPO) of each phase and the shape ratio of the hydrous phases. We have demonstrated that in a partially serpentinized peridotite, the olivine CPO characteristic of [100](010) dislocation glide is still preserved, and the high-temperature asthenospheric flow is preserved with a foliation normal to that of antigorite schist. The transformation of olivine into antigorite occurs predominantly (~ 75%) by the relationship (100)ol || (001)atg with [001]ol || [010]atg, with the (010)ol || (001)atg and [001]ol || [010]atg relationship observed in areas of weak antigorite CPO. Chlorite results from the phase transformation of olivine in a relatively static environment, as shown by the correlation between the olivine-chlorite CPOs with (100)ol || (100)ch, (010)ol || (001)ch and (001)ol || (010)ch. The fluid percolation that caused the localized metasomatism and partial hydration of the mantle occurred possibly along trans-lithospheric shear zones. The presence of chlorite induces the most important drop on the P-wave velocities and may help to explain some local low velocities in the fore-arc mantle wedges, but is unlikely to be of global importance due to its very high Vp/Vs ratio ~ 1.9. On the other hand, antigorite is the only phase that causes important modification on the propagation directions of P and S-waves, and the only phase to explain the polarization of the fastest shear waves parallel to the subduction trench.

  8. 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

  9. 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

  10. 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.

  11. Fast Breakdown of Hydrous Minerals may Trigger Intermediate-depth Earthquakes in subduction Zones

    NASA Astrophysics Data System (ADS)

    Chollet, M.; Daniel, I.; Koga, K. T.; Petitgirard, S.; Morard, G.

    2008-12-01

    Earthquakes are located along a double seismic zone (DSZ) in many subduction zones. Dehydration embrittlement is the mechanism usually proposed to explain these earthquakes, as the pressure-temperature (P,T) location of some hydrous minerals breakdown reactions coincide with intermediate-depth hypocenters. This model assumes that the release of water during dehydration reactions is fast enough to cause hydraulic rupture. Therefore, we have measured the kinetics of dehydration of antigorite, talc and 10Å phase at (P,T) conditions relevant to subduction zones. In situ real-time measurements were performed by X-Ray Diffraction (XRD) at high-P and high-T in the Paris- Edinburgh press at the European Synchrotron Radiation Facility (ESRF, ID27). Hydrous minerals were loaded in a transparent, pressure-sealed titanium capsule that ensured a closed thermochemical system. P and T were calculated from the unit-cell parameters of Au and NaCl, using the EoS cross calibration method. During dehydration, (P,T) conditions were kept constant and XRD patterns were acquired every 3 min. The extent of dehydration as a function of time was monitored by the variation in intensity of characteristic diffraction lines of both the hydrous phase and the reaction products. The fit of the isothermal kinetics data to the Avrami's equation and the texture of the reaction products after quench confirm that dehydration rates are limited by diffusion, as expected if a fluid is present. Minimum rates of fluid production during dehydration vary from 10-4 to 8.10-6 m3fluid.m-3rock.s-1. Such rates are definitely faster than the characteristic relaxation rate of the weakest mineral in subduction slabs, calculated as the inverse Maxwell relaxation time of antigorite. Hence, the sudden release of water by dehydration of antigorite, talc and 10Å phase is fast enough to provoke hydrofractures. We also show that rates of fluid release are comparable between antigorite, talc and 10Å phase. Consequently, we

  12. 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.

  13. Complexes of polyvinyl alcohol with insoluble inorganic compounds

    NASA Astrophysics Data System (ADS)

    Prosanov, I. Yu.; Bulina, N. V.; Gerasimov, K. B.

    2013-10-01

    Hybrid materials of polyvinyl alcohol-hydroxides/oxides of Be, Mg, Zn, Cd, B, Al, Cr, and Fe have been obtained. The studies have been carried out by the methods of optical spectroscopy, X-ray diffraction, and synchronous thermal analysis. Interpretation of experimental data is presented, presuming that, in systems with zinc, boron, aluminum, chromium, and iron hydroxides/oxides, interpolymeric complexes of polyvinyl alcohol with corresponding polymeric inorganic compounds are formed. They belong to a new class of materials with unusual structure containing chains of inorganic polymers isolated in the organic matrix.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. Hybrid organic-inorganic chlorozincate and a molecular zinc complex involving the in situ formed imidazo[1,5-a]pyridinium cation: serendipitous oxidative cyclization, structures and photophysical properties.

    PubMed

    Buvaylo, Elena A; Kokozay, Vladimir N; Linnik, Rostyslav P; Vassilyeva, Olga Yu; Skelton, Brian W

    2015-08-14

    Two novel compounds, the organic-inorganic hybrid [L](2)[ZnCl(4)] (1) and the coordination complex LZnCl(3) (2), where L is the 2-methyl-3-(pyridin-2-yl)imidazo[1,5-a]pyridinium cation, were prepared using the oxidative condensation-cyclization of 2-pyridinecarbaldehyde and CH(3)NH(2)·HCl in methanol in the presence of Zn(2+) cations. The metal-free interaction of the organic components afforded the salt [L][Cl]·1.5H(2)O (3). The use of methylamine hydrochloride instead of its aqueous solution is believed to be responsible for the cyclocondensation with the formation of L instead of the expected Schiff base ligand. Compounds 1-3 have been obtained as single crystals and characterized by elemental analysis, IR, NMR spectroscopy, and single-crystal X-ray diffraction techniques. The structure of 1 is described as layers of cations and anions stacked along the c-axis, with the minimum ZnZn distance being 8.435 Å inside a layer. In the crystal lattice of 3, the cations are arranged in stacks propagating along the a-axis; the 1D H-bonding polymer built of chloride ions and water molecules runs parallel to a column of stacked cations. The organic cations in salts 1 and 3 show various patterns of π-π stacking. The discrete molecular structure of 2 shows coordination of a Zn atom to the N(pyridyl) atom, which enables one of the chloride atoms attached to the metal centre to interact with a π-system of the positively charged imidazolium ring. Numerous C-HCl contacts in a 1-3 are seen as space-filling van der Waals interactions of minor importance in determining crystal packing. The (1)H NMR studies suggest that the Zn-N coordination found in the solid-state structure of 2 is not retained in dmso, and 1, 2 and 3 are completely dissociated in solution. The emission spectra of 1 and 2 (λ(max) = 455 and 445 nm, respectively) exhibit red-shifts of fluorescence wavelength when compared to 3 and differ in the shapes and maxima of the emission as well as in relative

  19. 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.

  20. 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.

  1. Evolution of the rheological and microstructural properties of olivine aggregates during dislocation creep under hydrous conditions

    NASA Astrophysics Data System (ADS)

    Tasaka, Miki; Zimmerman, Mark E.; Kohlstedt, David L.

    2016-01-01

    Since hydrogen plays an important role in dynamic processes in Earth's mantle, we conducted torsion experiments to shear strains of 0.6 to 5.0 on Fe-bearing olivine aggregates [(Mg0.5Fe0.5)2SiO4: Fo50] under hydrous conditions at T = 1200°C and P = 300 MPa. We deformed samples to high enough strains that a steady state microstructures were achieved, which allowed us to investigate the evolution of both the rheological and microstructural properties. The stress exponent of n ≈ 5.0 and the grain size exponent of p ≈ 0 determined by fitting the strain rate, stress, and grain size data indicate that our samples deformed by dislocation creep. Fourier transform infrared spectroscopy measurements on embedded olivine single crystals demonstrated that our samples were saturated with hydrogen during the deformation experiments. The lattice preferred orientation (LPO) of olivine changes as a function of strain due to competition among three slip systems: (010)[100], (100)[001], and (001)[100]. Observed strain weakening can be attributed to geometrical softening associated with development of LPO, which reduces the stress by ~1/3 from its peak value in constant strain rate experiments. The geometrical softening coefficient determined in this study is an important constraint for modeling and understanding dynamical processes in the upper mantle under hydrous conditions.

  2. 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.

  3. Density of hydrous silicate melt at the conditions of Earth's deep upper mantle

    NASA Astrophysics Data System (ADS)

    Matsukage, Kyoko N.; Jing, Zhicheng; Karato, Shun-Ichiro

    2005-11-01

    The chemical evolution of the Earth and the terrestrial planets is largely controlled by the density of silicate melts. If melt density is higher than that of the surrounding solid, incompatible elements dissolved in the melt will be sequestered in the deep mantle. Previous studies on dry (water-free) melts showed that the density of silicate melts can be higher than that of surrounding solids under deep mantle conditions. However, melts formed under deep mantle conditions are also likely to contain some water, which will reduce the melt density. Here we present data constraining the density of hydrous silicate melt at the conditions of ~410km depth. We show that the water in the silicate melt is more compressible than the other components, and therefore the effect of water in reducing melt density is markedly diminished under high-pressure conditions. Our study indicates that there is a range of conditions under which a (hydrous) melt could be trapped at the 410-km boundary and hence incompatible elements could be sequestered in the deep mantle, although these conditions are sensitive to melt composition as well as the composition of the surrounding mantle.

  4. 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.

  5. Hydrous olivine unable to account for conductivity anomaly at the top of the asthenosphere.

    PubMed

    Yoshino, Takashi; Matsuzaki, Takuya; Yamashita, Shigeru; Katsura, Tomoo

    2006-10-26

    The oceanic asthenosphere is observed to have high electrical conductivity, which is highly anisotropic in some locations. In the directions parallel and normal to the plate motion, the conductivity is of the order of 10(-1) and 10(-2) S m(-1), respectively, which cannot be explained by the conductivity of anhydrous olivine. But because hydrogen can be incorporated in olivine at mantle pressures, this observation has been attributed to olivine hydration, which might cause anisotropically high conductivity by proton migration. To examine this hypothesis, here we report the effect of water on electrical conductivity and its anisotropy for hydrogen-doped and undoped olivine at 500-1,500 K and 3 GPa. The hydrous olivine has much higher conductivity and lower activation energy than anhydrous olivine in the investigated temperature range. Nevertheless, extrapolation of the experimental results suggests that conductivity of hydrous olivine at the top of the asthenosphere should be nearly isotropic and only of the order of 10(-2) S m(-1). Our data indicate that the hydration of olivine cannot account for the geophysical observations, which instead may be explained by the presence of partial melt elongated in the direction of plate motion. PMID:17066031

  6. Magnesium isotope fractionation during hydrous magnesium carbonate precipitation with and without cyanobacteria

    NASA Astrophysics Data System (ADS)

    Mavromatis, Vasileios; Pearce, Christopher R.; Shirokova, Liudmila S.; Bundeleva, Irina A.; Pokrovsky, Oleg S.; Benezeth, Pascale; Oelkers, Eric H.

    2012-01-01

    The hydrous magnesium carbonates, nesquehonite (MgCO 3·3H 2O) and dypingite (Mg 5(CO 3) 4(OH) 2·5(H 2O)), were precipitated at 25 °C in batch reactors from aqueous solutions containing 0.05 M NaHCO 3 and 0.025 M MgCl 2 and in the presence and absence of live photosynthesizing Gloeocapsa sp. cyanobacteria. Experiments were performed under a variety of conditions; the reactive fluid/bacteria/mineral suspensions were continuously stirred, and/or air bubbled in most experiments, and exposed to various durations of light exposure. Bulk precipitation rates are not affected by the presence of bacteria although the solution pH and the degree of fluid supersaturation with respect to magnesium carbonates increase due to photosynthesis. Lighter Mg isotopes are preferentially incorporated into the precipitated solids in all experiments. Mg isotope fractionation between the mineral and fluid in the abiotic experiments is identical, within uncertainty, to that measured in cyanobacteria-bearing experiments; measured δ 26Mg ranges from -1.54‰ to -1.16‰ in all experiments. Mg isotope fractionation is also found to be independent of reactive solution pH and Mg, CO 32-, and biomass concentrations. Taken together, these observations suggest that Gloeocapsa sp. cyanobacterium does not appreciably affect magnesium isotope fractionation between aqueous fluid and hydrous magnesium carbonates.

  7. Hydrous pyrolysis in the field: closed-system diagenesis at high fluid flow

    SciTech Connect

    Hutcheon, I.; Abercrombie, H.; Shevalier, M.; Nahnybida, C.

    1989-03-01

    Diagenetic processes are studied by observing natural systems or by experimental hydrous pyrolysis of water-organic-rock mixtures. Steam-enhanced recovery is similar to hydrous pyrolysis but is done in a previously undisturbed geological setting with mass, time, and temperature closer to natural diagenetic systems. Chemical and isotopic compositions of produced water and gas were determined for wellhead samples obtained from quartz-rich and lithic reservoirs. Estimates of reservoir temperature were made using the silica and Na-K geothermometers and agree with temperatures estimated from /sup 13/C//sup 13/C partitioning between bicarbonate and CO/sub 2/. Temperature and fluid composition data are portrayed on activity diagrams and show that minerals (illite, chalcedony, chlorite, analcime, and smectite) rapidly reach equilibrium with waters. Mineral reactions inferred from produced waters are different in quartz-rich and lithic reservoirs and agree with mineral reactions observed in post-steam cores. Carbon isotopic data indicate that carbonate minerals are the source of produced CO/sub 2/. Comparison of the buffering potential of aqueous carbonate species, carbonate minerals, organic acids, and silicate hydrolysis shows that silicates have the greatest potential to buffer pH. The authors data are consistent with pH control by silicate hydrolysis and indicate that silicate-carbonate reactions may be a major source of CO/sub 2/ during diagenesis. More generally, their results show that a diagenetic system of high fluid flow can be approximated by closed-system behavior.

  8. 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.

  9. 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.

  10. 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.

  11. 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)

  12. 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.

  13. 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.

  14. CHEMICAL SPECIATION OF INORGANIC COMPOUNDS UNDER HYDROTHERMAL CONDITIONS

    EPA Science Inventory

    This research will utilize the high-intensity x-rays available at the Advance Photon Source (APS) to study the inorganic chemistry occurring during the hydrothermal oxidation of tank waste and the chemistry associated with tank waste vitrification. Although the chemical conversio...

  15. 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.

  16. Inorganic nanostructured materials for high performance electrochemical supercapacitors

    NASA Astrophysics Data System (ADS)

    Liu, Sheng; Sun, Shouheng; You, Xiao-Zeng

    2014-01-01

    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.

  17. 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

    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

  18. Creation and Deformation of Hydrous Lithosphere at the Southern Mariana Margin

    NASA Astrophysics Data System (ADS)

    Martinez, F.; Kelley, K. A.; Stern, R. J.

    2012-04-01

    Mantle lithosphere formed at mid-ocean seafloor spreading centers is thought to be essentially anhydrous because water is strongly partitioned into melt and removed from the mantle during crustal formation. Since water weakens olivine this dehydration process is also thought to strengthen oceanic mantle lithosphere above solidus depths, perhaps helping to focus deformation and melt delivery to the narrow plate boundary zones observed at mid-ocean ridges. In contrast, convergent margins are sites of high water flux from subducting slabs and thereby provide an opportunity to study the creation and deformation of lithosphere in a hydrous environment. The southern Mariana margin presents a rare case in which the upper plate is undergoing active extension parallel to the trench and directly above the subducting slab. The extension has rifted preexisting Paleogene lithosphere resulting in the present-day creation of new lithosphere in this hydrous environment. Here we present preliminary results from R/V Thomas G. Thompson cruise TN273 in December 2011-January 2012 utilizing the Hawaii Mapping Research Group's IMI-30, a 30 kHz deep-towed side-scan sonar, and ship-based Simrad EM302 multibeam bathymetry. The sidescan sonar imagery and multibeam bathymetry map the tectonic and volcanic structure of a 32 x 80 km area referred to as the southeast Mariana forearc rifts (SEMFR), which extend from near the backarc spreading center toward the trench. The sonar imagery shows a complex volcanic and tectonic structure with no single spreading or rifting axis. Volcanism appears to be widely dispersed and separated by faulted areas. Bathymetry data show several rifts spanning this area but no single rift appears to be focusing tectonic activity as earthquake seismicity is broadly distributed across this region. The data depict a broad volcano-tectonic zone of complex deformation and distributed volcanism unlike the narrow plate boundary zones of mid-ocean ridges. This distributed

  19. 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

  20. THE REDUCTION OF INORGANIC SULPHATE TO INORGANIC SULPHITE IN THE SMALL INTESTINE OF THE RAT.

    PubMed

    ROBINSON, H C

    1965-03-01

    1. Whole scrapings of rat intestinal mucosa were incubated with carrier-free sodium [(35)S]sulphate. Radioactivity was found in S-sulphocysteine and to a small extent in S-sulphoglutathione. 2. Whole scrapings of rat intestinal mucosa incubated with carrier-free sodium [(35)S]sulphate and oxidized glutathione formed S[(35)S]-sulphoglutathione as the main radioactive product. The amount of S[(35)S]-sulphocysteine formed was considerably lower than in a control that contained no oxidized glutathione. 3. The supernatant fraction of homogenates of rat intestinal mucosa catalyses the NADPH-dependent reduction of adenosine 3'-phosphate 5'-sulphatophosphate to inorganic sulphite. NADH or GSH fail to replace NADPH as reducing agents. 4. The formation of inorganic [(35)S]sulphite from inorganic [(35)S]-sulphate may account for the incorporation of [(35)S]sulphate into S-sulphoglutathione by the small intestine of the rat in vivo and in vitro. PMID:14340059

  1. The reduction of inorganic sulphate to inorganic sulphite in the small intestine of the rat

    PubMed Central

    Robinson, H. C.

    1965-01-01

    1. Whole scrapings of rat intestinal mucosa were incubated with carrier-free sodium [35S]sulphate. Radioactivity was found in S-sulphocysteine and to a small extent in S-sulphoglutathione. 2. Whole scrapings of rat intestinal mucosa incubated with carrier-free sodium [35S]sulphate and oxidized glutathione formed S[35S]-sulphoglutathione as the main radioactive product. The amount of S[35S]-sulphocysteine formed was considerably lower than in a control that contained no oxidized glutathione. 3. The supernatant fraction of homogenates of rat intestinal mucosa catalyses the NADPH-dependent reduction of adenosine 3′-phosphate 5′-sulphatophosphate to inorganic sulphite. NADH or GSH fail to replace NADPH as reducing agents. 4. The formation of inorganic [35S]sulphite from inorganic [35S]-sulphate may account for the incorporation of [35S]sulphate into S-sulphoglutathione by the small intestine of the rat in vivo and in vitro. PMID:14340059

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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?

  7. Elasticity of Hydrous Olivine Polymorphs: Implications for Seismic Structure of the Transition Zone

    NASA Astrophysics Data System (ADS)

    Duffy, T. S.; Mao, Z.; Jacobsen, S. D.; Jiang, F.; Smyth, J. R.; Holl, C. M.; Frost, D. J.

    2007-12-01

    The presence of water in the upper mantle and transition zone has the potential to explain various phenomena such as shear velocity anomalies or uplift and broadening of the 410-km discontinuity. The presence of H2O in the transition zone has also been frequently invoked to reconcile laboratory elasticity data on olivine polymorphs with seismic data for the amplitude of the 410-km discontinuity (Li et al., 2001; Chambers et al., 2005). Recently, we have measured the single-crystal elastic properties of hydrous olivine (Jacobsen et al., 2006) and a suite of hydrous wadsleyites (Mao et al., 2007a) at ambient conditions and one hydrous wadsleyite composition (0.84 wt% H2O) up to 12 GPa (Mao et al., 2007b). These data provide new constraints on elastic moduli and their pressure derivatives for hydrous olivine and wadsleyite. Using this data, we first examine the effect of H2O on bulk sound velocities under transition zone conditions because anelastic effects can be neglected in this case. At 410 km depth (~13.8 GPa, along a 1400°C adiabat), the bulk sound velocity of wadsleyite with 1 wt% H2O is 3.1% lower than for dry wadsleyite. Comparison of the seismic velocity jump across the 410-km discontinuity with the measured velocity contrast between wadsleyite and olivine provides a means to estimate the olivine abundance at 410-km depth. For mantle wadsleyite with 0.1-0.2 wt% H2O (Huang et al., 2005) and using experimentally determined olivine- wadsleyite H2O partition coefficients, the olivine abundance is found to be 40%, much lower than a pyrolite model. In order for a pyrolite composition to satisfy the seismic data, 1.2 wt. % H2O is needed in wadsleyite- a value greater than its maximum solubility under these conditions. The anomalously steep seismic gradient in the transition zone has been another feature of the region that has long defied explanation. We show that the seismic gradient can be matched if there is a gradient in H2O concentration across the transition

  8. Post-stishovite transition in hydrous aluminous SiO2

    NASA Astrophysics Data System (ADS)

    Umemoto, Koichiro; Kawamura, Katsuyuki; Hirose, Kei; Wentzcovitch, Renata M.

    2016-06-01

    Lakshtanov et al. (2007) showed that incorporation of aluminum and some water into SiO2 significantly reduces the post-stishovite transition pressure in SiO2. This discovery suggested that the ferroelastic post-stishovite transition in subducted MORB crust could be the source of reflectors/scatterers with low shear velocities observed in the mid to upper lower mantle. A few years later, a similar effect was observed in anhydrous Al-bearing silica. In this paper, we show by first principles static calculations and by molecular dynamics using inter-atomic potentials that hydrogen bonds and hydrogen mobility play a crucial role in lowering the post-stishovite transition pressure. A cooperative redistribution of hydrogen atoms is the main mechanism responsible for the transition pressure reduction in hydrous aluminous stishovite. The effect is enhanced by increasing hydrogen concentration. This perspective suggests a potential relationship between the depth of seismic scatterers and the water content in stishovite.

  9. 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. PMID:24432588

  10. 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??.

  11. 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.

  12. 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.

  13. 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

  14. Extracting inorganics from scrap tires

    SciTech Connect

    Cummings, R.; Wertz, D.L.

    1995-12-31

    Scrap tires contain several inorganic moieties in abundances >0.5% which are impregnated into their carbonaceous matrix. These inorganic species are known to produce acid rain, toxic aerosols, and boiler scale and could produce unwanted catalytic effects as well. It is our position that the potential of recycling scrap tires would be considerably enhanced if the inorganics in question - S, Ca, and Zn - were removed prior to attempts to upgrade the carbonaceous matrix. Using non-mechanical methods, we are attempting to cleave the adherence between the co-polymer matrix and to extract the inorganics. The efficiency of our methods is being measured by wavelength dispersive x-ray spectrometry and by other methods.

  15. Dynamics of the Axial Melt Lens/Dike transition at fast spreading ridges: assimilation and hydrous partial melting

    NASA Astrophysics Data System (ADS)

    France, L.; Ildefonse, B.; Koepke, J.

    2009-04-01

    Recent detailed field studies performed in the Oman ophiolite on the gabbro/sheeted dike transition, compared to corresponding rocks from the EPR drilled by IODP (Site 1256), constrain a general model for the dynamics of the axial melt lens (AML) present at fast spreading ridges (France et al., 2008). This model implies that the AML/dike transition is a dynamic interface migrating up- and downward, and that the isotropic gabbro horizon on top of the igneous section represents its fossilization. It is also proposed that upward migrations are associated to reheating of the base of the sheeted dike complex and to assimilation processes. Plagiogranitic lithologies are observed close to the truncated base of the dikes and are interpreted to represent frozen melts generated by partial melting of previously hydrothermalized sheeted dikes. Relicts of previously hydrothermalized lithologies are also observed in the fossil melt lens, and are associated to lithologies that have crystallized under high water activities, with clinopyroxene crystallizing before plagioclase, and An-rich plagioclase. To better understand our field data, we performed hydrous partial melting experiments at shallow pressures (0.1 GPa) under slightly oxidizing conditions (NNO oxygen buffer) and water saturated conditions on hydrothermalized sheeted dike sample from the Oman ophiolite. These experiments have been performed between 850°C and 1030°C; two additional experiments in the subsolidus regime were also conducted (750°C and 800°C). Clinopyroxenes formed during incongruent melting at low temperature (<910°C) have compositions that match those from the corresponding natural rocks (reheated base of the sheeted dike and relicts of assimilated lithologies). In particular, the characteristic low TiO2 and Al2O3 contents are reproduced. The experimental melts produced at low temperatures correspond to compositions of typical natural plagiogranites. In natural settings, these silicic liquids would be

  16. 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.

  17. 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

  18. 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

  19. Strength of inorganic glass

    SciTech Connect

    Kurkjian, C.R.

    1985-01-01

    This book presents information on the following topics: a look at the history of glass strength; atomistic theory of fracture; surface chemistry in relation to the strength and fracture of silicate glasses; high-speed photographic investigations of the dynamic localized loading of some oxide glasses; a correction for measurements of contact area using Newton's rings; envionmentally enhanced crack growth; fatigue in glass; behavior of flaws in fused silica fibers; fracture toughness of chalcogenide glasses and glass-ceramics; fracture analysis of glass surfaces; and fracture mechanics parameters for glasses - a compilation and correlation.

  20. 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

  1. 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

  2. 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.

  3. Synthesis of tungsten oxide tapered needles with nanotips

    NASA Astrophysics Data System (ADS)

    Wang, Shiliang; He, Yuehui; Zou, Jin; Cao, Peng; Jiang, Yao; Huang, Baiyun; Liu, C. T.; Liaw, P. K.

    2007-05-01

    Tungsten oxide tapered needles with nanotips were synthesized on a large scale by reacting tungsten nanopowders with hydrous nickel nitrate in hydrogen atmosphere. The resultant tungsten oxide needles have lengths more than 100 μm, root diameters of several hundred nanometers and tip diameters of several nanometers, showing a perfectly axisymmetric configuration. HRTEM and SAED analyses showed that the synthesized tungsten oxide tapered needles have a single-crystalline structure with growth direction of [0 1 0]. The effects of the experimental conditions (the ratio between tungsten and hydrous nickel nitrate, the size of tungsten powders, and the reaction atmosphere) on the morphology of the products were systematically investigated. It was found that tungsten oxide nanowires, submicro-/micro-whiskers and microtubules could be facilely obtained under different experimental conditions. The unique configuration and the single-crystal structure of the tapered needles may make them a potential candidate for field emitters and probing tips.

  4. Determination of thermal stability of specific biomarker lipids of the freshwater fern Azolla through hydrous pyrolysis

    NASA Astrophysics Data System (ADS)

    Sap, Merel; Speelman, Eveline N.; Lewan, Michael D.; Sinninghe Damsté, Jaap S.; Reichart, Gert-Jan

    2010-05-01

    Enormous blooms of the free-floating freshwater fern Azolla occurred within the Arctic Basin during an extended period of ~1.2 Ma during the middle Eocene (Brinkhuis et al. 2006; Speelman et al., GB, 2009). The sustained growth of Azolla, currently ranking among the fastest growing plants on Earth, in a major anoxic basin may have substantially contributed to decreasing atmospheric CO2 levels by burial of Azolla-derived organic matter. Speelman et al. (OG, 2009) reported biomarkers for Azolla (1,w20 C32 - C36 diols, structurally related C29 ω20,ω21 diols, C29 1,20,21 triols, C29 dihydroxy fatty acids as well as a series of wax esters containing these mono- and dihydroxy lipids), which can be used to reconstruct palaeo-environmental conditions. Here we assess the thermal stability of these compounds, to extend their biomarker potential. We specifically focused on the thermal stability of the Azolla biomarkers using hydrous pyrolysis in order to determine which burial conditions allow reconstruction of past occurrences of Azolla. In addition, hydrous pyrolysis was also performed on samples from the Eocene Arctic Ocean (ACEX core), to test if and how the biomarkers change under higher temperatures and pressures in situ. During hydrous pyrolysis, the biomass was heated under high pressure at temperatures ranging between 220 and 365°C for 72 hours. Four experiments were also run using different durations to explore the kinetics of biomarker degradation at specific temperatures. First results indicate that the Azolla specific diols are still present at 220°C, while the corresponding wax esters are already absent. At 300°C all Azolla specific biomarkers are destroyed. More specific determination of the different biomarkers' stability and kinetics would potentially allow the reconstruction of the temperature and pressure history of Azolla deposits. Literature: • Brinkhuis, H., Schouten, S., Collinson, M. E., Sluijs, A., Sinninghe Damste, J. S., Dickens, G. R., Huber

  5. 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

  6. Preparation of monodispersed cobalt-boron spherical nanoparticles and their behavior during the catalytic decomposition of hydrous hydrazine

    SciTech Connect

    Tong, D.G.; Zeng, X.L.; Chu, W.; Wang, D.; Wu, P.

    2010-04-15

    Monodispersed cobalt-boron spherical nanoparticles have been prepared through solution plasma processing in the presence of hexadecyltrimethyl ammonium bromide for the first time. The particle size of cobalt-boron can be adjusted by changing either the plasma time or the concentration of hexadecyltrimethyl ammonium bromide. The samples were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy. During the decomposition of hydrous hydrazine, the obtained monodispersed cobalt-boron spherical nanoparticles exhibit higher catalytic activity and hydrogen selectivity than regular cobalt-boron prepared by direct reduction of Co{sup 2+} with BH{sub 4}{sup -}. The experimental investigations indicate that hydrous hydrazine along with the monodispersed cobalt-boron spherical nanoparticles may find application in small-scale on-board hydrogen storage and supply.

  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. PMID:17774694

  8. Transport and thermodynamic properties of hydrous melts in the system An-Di.

    NASA Astrophysics Data System (ADS)

    Giordano, D.; Potuzak, M.; Romano, C.; Russell, J. K.; Nowak, M.; Dingwell, D. B.

    2006-12-01

    The thermodynamic and transport properties hydrous silicate melts are of fundamental importance for characterization of the dynamics and energetics associated with silicate melts in the Earth. The literature concerning the transport and calorimetric properties of hydrous silicate melts remains scarce. With few exceptions little has been effectively done in order to provide chemical models that bridge the gap between the description of both complex and simple systems. The An-Di system is of general interest to geochemists as well as petrologists because it serves as a simple analogue for basaltic compositions. It was chosen here due to the combination of its simple chemical description and the presence of an extensive database of published experimental data on both its transport and thermodynamic properties. We have measured the viscosity (η)), the glass transition temperatures (Tg) and the heat capacity (Cp) of silicate melts in the An-Di system containing up to 3 wt.% of dissolved H2O. Viscosity data were obtained by using the dilatometric method of micropenetration, whereas a differential scanning calorimeter (DSC) was employed to determine the glass transition temperatures and the heat capacities. In order to characterize the well-known cooling/heating rate dependence of the glass transition temperatures the calorimetric measurements were performed at heating/cooling rate of 5, 10, 15 and 20 K/min. These results together with those of previous experimental studies have been used to provide a compositional model capable of calculating the Newtonian viscosity of melts as well as the Tg and Cp values for the An- Di+H2O system. The non-Arrhenian T-dependence of viscosity is accounted for by the Vogel-Fulcher- Tammann (VFT) and the Adam Gibbs (AG) equations. Our optimizations assume a common, high-T limit (A) for silicate melt viscosity, consistent with values provided by both theoretical and experimental studies. In particular, we also show that glass transition

  9. Compound-specific carbon isotope analysis of instantaneous gas generated from shaly coal during hydrous pyrolysis

    NASA Astrophysics Data System (ADS)

    Tsai, Wen-Yu; Sun, Chih-Hsien; Huang, Wuu-Liang

    2010-05-01

    Isotopes of natural gases have provided important information for indicating their maturation, origins and influencing factors during the generation processes. In order to distinguish compositions of gas generated at different intervals of maturities, the present study investigates the variation of compound-specific carbon isotope (CSI) ratios of hydrocarbon gases from a shaly coal by instantaneous hydrous pyrolysis, during which the earlier generated gas was evacuated before the start of next maturation stage. The experiments were conducted at ten different maturity stages (0.65 to 2.02 % Ro) from a terrestrial shaly coal with 0.48 % Ro. The gas products were analyzed by GC-IR-MS. The results show that, in general, the δ13C values of methane (C1), ethane (C2), propane (C3) slightly increase, then decrease and finally increase with increasing maturities. This reverse phenomenon indicates the heterogeneous and complex compositions of the kerogen. The isotope compositions of gases exhibit three distinct clusters in natural gas plot of δ13C values versus 1/n (where n is carbon number of the gaseous molecule), corresponding to three different groups of maturity stages. By linking the same maturity stage of δ13C values, all lines show nearly parallel in each group with consistently reverse trend of δ13C3 < δ13C2 > δ13C1. These three distinct clusters were also observed in the cross plotting of iC4/nC4 versus iC5/nC5 isomer ratios. This may imply that the kerogen is composed of three discrete structural domains which were progressively cracked at three major groups of maturity stages. The reverse trend was inconsistent with data for gas collected cumulatively in most prior pyrolysis experiments and the linear relationship predicted from kinetic isotope effect (KIE) model. Although the non-linear relationship or reverse trend, δ13C3 < δ13C2, was also reported for some natural gases, it was interpreted as a result of mixing from different source rocks or other

  10. 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

  11. 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.

  12. Concerning inorganic crystal structure types.

    PubMed

    Bergerhoff; Berndt; Brandenburg; Degen

    1999-04-01

    All representatives of an inorganic crystal structure type can be found systematically in the new database SICS (Standardized Inorganic Crystal Structures). It is derived from the Inorganic Crystal Structure Database (ICSD) by selecting the best determination of each phase. In addition, each entry is given in a standardized description and complemented by searchable descriptors Delta, which give the difference between all structures of an isopointal set. Because of the large number of structures the full information on relationships present can only be found by means of the new database itself. Some examples are given here in printed form. The limitations and the possibilities of expansion of SICS in terms of the concept of 'structure types' are demonstrated. PMID:10927350

  13. Inorganic composites for space applications

    NASA Technical Reports Server (NTRS)

    Malmendier, J. W.

    1984-01-01

    The development of inorganic composite materials for space applications is reviewed. The composites do not contain any organic materials, and therefore, are not subject to degradation by ultraviolet radiation, volatilization of constituents, or embrittlement at low temperatures. The composites consist of glass, glass/ceramics or ceramic matrices, reinforced by refractory whiskers or fibers. Such composites have the low thermal expansion, refractories, chemical stability and other desirable properties usually associated with the matrix materials. The composites also have a degree of toughness which is extraordinary for refractory inorganic materials.

  14. 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.

  15. 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

  16. 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.

  17. 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.

  18. 3D dynamics of hydrous thermal-chemical plumes in subduction zones

    NASA Astrophysics Data System (ADS)

    Zhu, G.; Gerya, T.; Yuen, D.; Connolly, J. A. D.

    2009-04-01

    Mantle wedges are identified as sites of intense thermal convection and thermal-chemical Rayleigh-Taylor instabilities ("cold plumes") controlling distribution and intensity of magmatic activity in subduction zones. To investigate 3D hydrous partially molten cold plumes forming in the mantle wedge in response to slab dehydration, we perform 3D petrological-thermomechanical numerical simulations of the intraoceanic one-sided subduction with spontaneously bending retreating slab characterized by weak hydrated upper interface. I3ELVIS code is used which is developed based on multigrid approach combined with marker-in-cell method with conservative finite-difference schemes. We investigated regional 800 km wide and 200 km deep 3D subduction models with variable 200 to 800 km lateral dimension along the trench using uniform numerical staggered grid with 405x101x101 nodal points and up to 50 million markers. Our results show three patterns (roll(sheet)-, zig-zag- and finger-like) of Rayleigh-Taylor instabilities can develop above the subducting slab, which are controlled by effective viscosity of partially molten rocks. Spatial and temporal periodicity of plumes correlate well with that of volcanic activity in natural intraoceanic arcs such as Japan. High laterally variable surface heat flow predicted in the arc region in response to thermal-chemical plumes activity is also consistent with natural observations.

  19. 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.

  20. 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.

  1. Textural and chemical consequences of interaction between hydrous mafic and felsic magmas: an experimental study

    NASA Astrophysics Data System (ADS)

    Pistone, Mattia; Blundy, Jonathan D.; Brooker, Richard A.

    2016-01-01

    Mantle-derived, hydrous mafic magmas are often invoked as a mechanism to transfer heat, mass and volatiles to felsic plutons in the Earth's crust. Field observations suggest that mafic, water-rich magmas often intrude viscous felsic crystal-rich mushes. This scenario can advect water from the crystallising mafic magma to the felsic magma, leading to an increase in melt fraction in the felsic mush and subsequent mobilisation, at the same time as the mafic magma becomes quenched through a combination of cooling and water loss. To investigate such a scenario, we conducted experiments on a water-undersaturated (4 wt% H2O in the interstitial melt) dacitic crystal mush (50-80 vol% quartz crystals) subject to volatile supply from a water-saturated (≥6 wt% H2O) andesite magma at 950 °C and 4 kbar. Our experimental run products show unidirectional solidification textures (i.e. comb layering) as crystals nucleate at the mafic-felsic interface and grow into the mafic end-member. This process is driven by isothermal and isobaric undercooling resulting from a change in liquidus temperature as water migrates from the mafic to the felsic magma. We refer to this process as "chemical quenching" and suggest that some textures associated with natural mafic-felsic interactions are not simply cooling-driven in origin, but can be caused by exsolution of volatiles adjacent to an interface, whether a water-undersaturated felsic magma (as in our experiments) or a fracture.

  2. 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.

  3. 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.

  4. Colloidal inorganic nanocrystals: Nucleation, growth and biological applications

    NASA Astrophysics Data System (ADS)

    Lynch, Jared James

    Colloidal inorganic nanocrystals are a class of material whose size ranges from a few nanometers to a hundred nanometers in dimension. These nanocrystals have size dependent properties that differ significantly from the bulk material counterparts. Due to their unique physical properties colloidal inorganic nanocrystals have several promising applications in a diverse range of areas, such as biomedical diagnosis, catalysis, plasmonics, high-density data storage and solar energy conversion. This dissertation presents the study of the formation of iron oxide nanocrystals under the influence of solvent and Ar gas bubbles, the phase transfer of metal oxide nanocrystals into water using inorganic ions, and the doping of semiconductor CdS/ZnS core/shell nanocrystals with copper and silver ions. First, the formation of iron oxide nanocrystals is investigated in the presence of boiling solvent or Ar bubbles. Using a non-injection based synthesis method, the thermal decomposition of iron oleate was studied under various reaction conditions, and the role of the bubbles on the nucleation and growth of iron oxide nanocrystals was determined. Kinetics studies were used to elucidate how latent heat transfer from the bubbles allows for "active monomers" to form preferentially from exothermic reactions taking place during nucleation. General insights into colloidal inorganic nanocrystal formation are discussed. Second, a non-injection based synthesis for CdS/ZnS core/shell nanocrystals is used to make high quality semiconductor particles which are intentionally doped with Cu or Ag ions. The Ag ions effect on the optical properties of the CdS/ZnS nanocrystals is investigated. The absorption and fluorescence of the samples is measured as a function of time and temperature. Proposed mechanisms for the observations are given and thoroughly discussed. Comparisons between previous results for Cu doped CdS/ZnS nanocrystals are also made to further understand how doping of semiconductor

  5. 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.

  6. 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)

  7. 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)

  8. 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.

  9. 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. PMID:24384725

  10. Anomalous elastic behaviour of hydrous sanidine megacrysts from the Eifel, Germany

    NASA Astrophysics Data System (ADS)

    Schreuer, Jürgen; Demtröder, Kathrin; Sondergeld, Peter; Dehn, Sara

    2010-05-01

    contrast, the hydrous Eifel sanidines show an exponentially increasing ultrasound dissipation above 800°C followed by a rapid irreversible softening of all resonance frequencies by about 8% above 970°C. The observed anomalies are most likely related to the mobility of water dissolved in the crystal structure of the Eifel sanidines. On first heating the water slowly gets mobile above 800°C and leaves the crystal structure at about 970°C. The high mobility of the water molecules allow for a new, less ordered equilibrium state to be reached on the time scale of the experiment. The increase of the configurational entropy as well as the development and propagation of micro-cracks lead to an elastic softening of the macroscopic crystals. [1] C. Zeipert and W. Wondratschek: Ein ungewöhnliches Temperverhalten bei Sanidinen von Volkesfeld/Eifel. N. Jb. Mineral., Mh. 9 (1981) 407-415. [2] A. Beran: A model of water allocation in alkali feldspar, derived from infrared-spectroscopic investigations. Phys. Chem. Minerals 13 (1986) 306-310. [3] E.A. Johnson and G.R. Rossman: A survey of hydrous species and concentrations in igneous feldspars. Am. Min. 89 (2004) 586-600.

  11. Effects of thermal maturation on steroid hydrocarbons as determined by hydrous pyrolysis of Phosphoria Retort Shale

    NASA Astrophysics Data System (ADS)

    Lewan, M. D.; Bjorøy, M.; Dolcater, D. L.

    1986-09-01

    Hydrous pyrolysis experiments on the Phosphoria Retort Shale generate bitumen extracts and expelled oils that have steroid hydrocarbons with m/z 217-, 231-, and 253-mass Chromatographic distributions that are similar to those of bitumens and crude oils in the natural system. These experiments agree with the natural observations that diasteroid hydrocarbons increase relative to their regular counterparts with increasing thermal stress, while their C 27 through C 29 proportionality shows a slight enrichment in C 27. Relative concentrations of 20S to 20R configurations of 24-ethyl-14α,17α-cholestane show the expected increase with increasing thermal stress into the early part of the primary oil generation stage, but thereafter decrease with increasing thermal stress. If this reversal is found in high maturity sections of the natural system, the utility of this transformation as a maturity index will be limited. Triaromatic- to monoaromatic-steroid hydrocarbon concentrations increase with increasing thermal stress as observed in the natural system. Preferred migration of monoaromatic steroid hydrocarbons from bitumen extracts to expelled oils places considerable doubt on currently employed kinetic models for this aromatization reaction. As in the natural system, the experiments show relative concentrations of low-molecular weight- to high-molecular weight-triaromatic steroid hydrocarbons to increase with increasing thermal stress. Assuming a first-order reaction rate, the apparent activation energy and pre-exponential factor for this apparent side-chain cleavage reaction are 175.59 kJ mol -1 and 2.82 × 10 13hr-1, respectively. These kinetic parameters are geologically reasonable and are similar to those for the overall generation of expelled oil.

  12. Hydrous Na-garnet from Garnet Ridge; products of mantle metasomatism underneath the Colorado Plateau

    NASA Astrophysics Data System (ADS)

    Sakamaki, Kunihiko; Sato, Yuto; Ogasawara, Yoshihide

    2016-12-01

    This is the first report on amphibole exsolution in pyrope from the Colorado Plateau. Pyrope crystals delivered from mantle depths underneath the Colorado Plateau by kimberlitic volcanism at 30 Ma were collected at Garnet Ridge, northern Arizona. The garnet grains analyzed in this study occur as discrete crystals (without adjacent rock matrix) and are classified into two major groups, Cr-rich pyrope and Cr-poor pyrope. The Cr-poor pyrope group is divided into four subgroups based on exsolved phases: amphibole lamella type, ilmenite lamella type, dense lamellae type, and clinopyroxene/amphibole lamellae type. Exsolved amphibole occurs in amphibole lamella type, dense lamellae type, and clinopyroxene/amphibole lamellae type of Cr-poor pyrope. The amphibole crystals tend to have preferred orientations in their garnet hosts and occur as monomineralic hexagonal or rhombic prisms and tablets, and as multimineralic needles or blades with other exsolved phases. Exsolved amphibole has pargasitic compositions (Na2O up to 1.6 apfu based on 23 oxygen). Garnet host crystals that have undergone amphibole exsolution have low OH contents (2-42 ppmw H2O) compared to garnets that do not have amphibole lamellae (up to 115 ppmw H2O). The low OH contents of garnets hosting amphibole lamellae suggest loss of OH from garnet during amphibole exsolution. Amphibole exsolution from pyrope resulted from breakdown of a precursor "hydrous Na-garnet" composition (Mg,Na+ x)3(Al2 - x, Mgx)2Si3O12 - 2x(OH)2x. Exsolution of amphibole and other phases probably occurred during exhumation to depths shallower than 100 km prior to volcanic eruption.

  13. 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.

  14. Configurational entropy modeling of the viscosity of hydrous albitic, granitic and rhyolitic melts

    NASA Astrophysics Data System (ADS)

    Whittington, A.; Bouhifd, A.; Hofmeister, A.; Richet, P.; Romine, W.

    2008-12-01

    The transition from ductile to brittle behavior in silicate melts occurs when strain rates exceed relaxation rates, which are closely related to the viscosity. Viscosity is very sensitive to temperature, melt composition and dissolved water content. We present 210 new viscosity data for obsidians from Mono Crater, California, containing up to <1.2 wt.% H2O. In conjunction with literature data, we used configurational entropy theory to model the viscosity (η) and glass transition temperature (Tg) of hydrous synthetic NaAlSi3O8 and haplogranite melts, and complex (natural) leucogranites and high-silica rhyolites. In the equation log η = Ae + Be/TSconf(T), the Sconf term is configurational entropy, which varies with T depending on the configurational heat capacity of the melt. The variables Ae, Be, and Sconf(Tg) were parameterized as a function of water content for each of the four data sets. With the simplest assumption of ideal mixing between silicate and water components, configurational entropy models with between 4 and 10 fitting parameters reproduce experimentally determined η-T-X(H2O) relationships significantly better than previous literature models based on empirical equations, and have the advantage of being based on thermodynamic theory. Our preferred configurational entropy models have root-mean-square deviations of 0.26 log units for NaAlSi3O8 (n = 77), 0.16 log units for haplogranite (n = 55), 0.28 log units for peraluminous granites (n = 79), and 0.36 log units for Mono Crater rhyolites (n = 262). The majority of the data were collected in the viscosity range 108 to 1013 Pa.s, so the new models place tight constraints on the glass transition in silicic melts, especially at low water contents relevant to conduits and domes.

  15. 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.

  16. 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.

  17. Ultrathin inorganic molecular nanowire based on polyoxometalates.

    PubMed

    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

  18. 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

  19. 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

  20. 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.

  1. 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

  2. Evaluating Re-Os systematics in organic-rich sedimentary rocks in response to petroleum generation using hydrous pyrolysis experiments

    NASA Astrophysics Data System (ADS)

    Rooney, Alan D.; Selby, David; Lewan, Michael D.; Lillis, Paul G.; Houzay, Jean-Pierre

    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 elemental

  3. 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

  4. 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.

  5. Superplasticity in hydrous melt-bearing dunite: Implications for shear localization in Earth’s upper mantle

    NASA Astrophysics Data System (ADS)

    Ohuchi, Tomohiro; Nishihara, Yu; Kawazoe, Takaaki; Spengler, Dirk; Shiraishi, Rei; Suzuki, Akio; Kikegawa, Takumi; Ohtani, Eiji

    2012-06-01

    Deformation experiments on hydrous melt-bearing dunite (olivine+4 vol% orthopyroxene+4 vol% clinopyroxene with less than 2.5 vol% of the melt phase) were conducted at pressures of 1.3-5.7 GPa and temperatures of 1270-1490 K in order to explore the effect of intergranular fluids on the plastic flow of olivine in Earth's upper mantle. The strain rate was proportional to steady-state creep strength to the 2.1 power, and the creep strength markedly increased with increase in grain size. Developments of the crystallographic preferred orientation of olivine and flattening of olivine grains were hardly observed even after 33-55% shortening of the samples. These observations show that grain boundary sliding (GBS) dominated the deformation of olivine (i.e., superplasticity). The creep strength of hydrous melt-bearing dunite was 2-5 times lower than that of melt-free dunite. The dependence of creep rate on melt fraction is known to be expressed empirically as ɛ˙(ϕ)=ɛ˙(0)exp(αϕ), where α is a constant and ϕ is the melt fraction. The experimentally obtained value of α was in the range of 150-230, corresponding to 5-7 times the reported values for the olivine-basalt system at 0.3 GPa (i.e., creep strength of dunite was efficiently reduced by the hydrous melt). Superplasticity is the dominant creep mechanism of olivine in fluid-bearing fine-grained peridotites under low-temperature and high-stress conditions (i.e., peridotite shear zones in the upper mantle). Superplasticity induced by geological fluids would play an important role in the shear localization (and thus initiation of subduction) in the upper mantle.

  6. Seismic velocities and anisotropy in subducting slabs: Constrains from high pressure Brillouin scattering studies on hydrous phases

    NASA Astrophysics Data System (ADS)

    Sanchez-Valle, C.

    2009-05-01

    Water transported and released into the upper mantle via subduction of oceanic lithosphere has a profound effect on the physical and mechanical properties of mantle materials and may trigger earthquakes and partial melting. The identification of water storage sites in the slab is therefore necessary to constrain H2O recycling through subduction zones and the effect that its circulation on a global scale has on the dynamics of the Earth's interior. As seismology represents the preferred method to detect hydration, knowledge of the sound velocities and elastic properties of candidate hydrous minerals are essential to interpret the seismic velocity structure and anisotropy of subducted plates. Dense hydrous magnesium silicates (DHMS) are recognized as important host for H2O in the slab, but their elastic properties under the appropriate pressure-temperature conditions are still poorly constrained. Here I present recent high-pressure Brillouin spectroscopy measurements to determine the sound velocities and single-crystal elastic properties of Fe-bearing phase A (phA) and phase E (phE), two DHMS that may transport water into the upper mantle and transition zone. Measurements were performed on samples compressed up to 16.5(2) GPa in the diamond-anvil cell. The results provide new insights into the behavior of hydrous minerals under subduction conditions and the possibility of identifying hydration through seismic observations. In both cases, the shear properties of the materials are important factors in the conclusions reached. The compressional (VP) and shear (VS) wave velocities of phA and phE are significantly lower than those of other phases in slab peridotite with whom they coexist. The new data is used with existing thermoelastic data to compute the density and seismic velocity structure of harzburgitic subducted slabs with various degrees of hydration at pressures corresponding to the upper mantle and transition zone. The results suggest that the seismic

  7. Highly efficient Ni@Ni-Pt/La2O3 catalyst for hydrogen generation from hydrous hydrazine decomposition: Effect of Ni-Pt surface alloying

    NASA Astrophysics Data System (ADS)

    Zhong, Yu-Jie; Dai, Hong-Bin; Jiang, Yuan-Yuan; Chen, De-Min; Zhu, Min; Sun, Li-Xian; Wang, Ping

    2015-12-01

    Hydrous hydrazine has received increasing attention as a promising hydrogen carrier owing to its many favorable attributes, such as high hydrogen content, low material cost, stable liquid state at ambient conditions, and free of solid decomposition byproduct. Herein, we report the synthesis of a supported core-shell structured Ni@Ni-Pt/La2O3 catalyst by a combination of co-precipitation and galvanic replacement methods. The catalyst exhibits high catalytic activity and 100% selectivity towards hydrogen generation from hydrous hydrazine at mild conditions, which outperforms most reported hydrous hydrazine decomposition catalysts. The favorable catalytic performance of the Ni@Ni-Pt/La2O3 catalyst is correlated with the Pt-induced electronic and geometric modifications on the catalyst surface.

  8. 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

  9. 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

  10. 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

  11. 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

  12. 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?

  13. 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

  14. 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

  15. On the behavior of redox pairs in anhydrous and hydrous silicate melts: from the oxygen electrode to the mutual interactions of Fe and S

    NASA Astrophysics Data System (ADS)

    Moretti, R.

    2005-12-01

    The need of techniques for determining the oxidation state of magmas from iron and/or sulfur redox ratios has pushed scientists to yield composition-based semi-empirical equations, without much interest for the understanding of how electron transfer takes place, thus disregarding true, or at least most plausible, redox exchanges occurring in melts. Not secondary, it has generated notations (i.e., chemical equilibria) in which standard states, species and components are mixed. Let us then go back to basics, by taking the most geologically important element having multiple oxidation states: iron. In order to model redox exchanges we need i) a formalism for acid-base reactions in silicate melts, ii) a reference electrode, iii) a model for computing proportions and activities of species intervening in acid-base exchanges and redox electrodes, including that of reference. Briefly, the above requirements converge in the adoption of the normal oxygen electrode plus the Toop-Samis polymeric approach, which is based on the ionic Temkin notation (Ottonello et al., 2001). Therefore, in silicate melts redox processes and polymerization are intimately related. Under certain conditions, some unexpected features can be explored, such as the oxidation of iron in closed system with decreasing temperature. Let us now complicate the things by introducing the most geologically important volatile: water. Processing of data on the iron redox ratio in hydrous glasses allows one to model the role of composition, temperature, pressure and oxygen fugacity i) by assessing the acid-base properties of the water component in a notation consistent with the above and ii) by introducing volume terms of interest. The central role of water speciation can be then discussed in terms of its amphoteric behavior, in line with the earlier prediction of Fraser (1977) and the recent NMR findings of Xue and Kanzaki (2004). Finally, let us add another multiple valence state element such as S and investigate

  16. 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.

  17. 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.

  18. Effect of hydrolysis conditions on hydrous TiO2 polymorphs precipitated from a titanyl sulfate and sulfuric acid solution

    NASA Astrophysics Data System (ADS)

    Song, Hao; Liang, Bin; Lü, Li; Wu, Pan; Li, Chun

    2012-07-01

    The relationship between hydrolysis conditions and hydrous titania polymorphs obtained in a titanyl sulfate and sulfuric acid solution was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HRTEM). The results revealed that the feeding rate of the titanyl sulfate stock solution, the concentration of sulfuric acid, and the seed dosage of rutile crystal could significantly affect the hydrolysis rate, thus influencing the titania crystal phase. Hydrous TiO2 in the form of rutile, anatase, or the mixture of both could be obtained in solutions of low titanium concentrations and 2.5wt% to 15wt% sulfuric acid at 100°C. When the hydrolysis rate of titanium expressed by TiO2 was more than or equal to 0.04 g/(L·min), the hydrolysate was almost phase-pure anatase, while the main phase state was rutile when the hydrolysis rate was less than or equal to 0.01 g/(L·min). With the hydrolysis rate between 0.02 and 0.03 g/(L·min), the hydrolysate contained almost equal magnitude of rutile and anatase. It seems that although rutile phase is thermodynamically stable in very acidic solutions, anatase is a kinetically stable phase.

  19. 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

  20. 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

  1. 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. PMID:23339685

  2. 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.

  3. Physical and Molecular Biosignature Preservation in Hydrous Ferric Oxides: Implications for Detection wtih MSL and Future Missions

    NASA Astrophysics Data System (ADS)

    Williams, A. J.; Sumner, D. Y.; Eigenbrode, J. L.; Wilhelm, M. B.; Cook, C. L.; Mahaffy, P. R.

    2016-05-01

    Physical and molecular biosignature preservation in modern to 1000s-of-years-old iron-bearing environments and their potential for detection by instruments onboard the Curiosity rover and future surface missions.

  4. Dehydration of primordial hydrous rock in Ganymede: formation of the conductive core, the grooved terrain, and the contrasting interior from Callisto

    NASA Astrophysics Data System (ADS)

    Kimura, J.; Kuramoto, K.

    2011-12-01

    The small value of the moment of inertia factor and the strong intrinsic magnetic field observed for Ganymede are consistent with a highly differentiated interior with a conductive dense core. The Gany-mede's surface is commonly divided into two units, termed dark terrain and bright terrain. The latter, or grooved terrain, has been interpreted as grabens resulting from lithospheric extension. According to geological estimates, 3-4% increase in the satellite radius may be required for their formation. Hence Ganymede has likely undergone significant tempera-ture rise inside allowing the separation of a conduc-tive core and global expansion during its history. But its mechanisms still remain an open question. This study numerically investigates the possible influ-ence of hydrated rock on the thermal history of Ganymede. Here we assumes that Ganymede had an initial structure with a relatively thin H2O ice mantle and a low temperature primordial core made of the mixture of hydrous rock and Fe-sulfide similar to hydrated primitive meteorites. The primordial core is heated by the decay of long-lived radioactive nu-clides. The rise of core temperature is kept slow after the occurrence of effective thermal convection in the core having low viscosity (~1E20 Pas) of hydrous rock. However, once the temperature reaches the dehydration point (~900 K) then the highly viscous, anhydrous region begins to grow associated with the release of H2O to the mantle. The core temperature thereby becomes to increase faster with accelerating the further dehydration of primitive matter. The core temperature subsequently exceeds the eutectic point of the Fe-bearing sulfide and oxide so that the formation of a conductive dense core could occur by their gravitational segregation. Such thermal runaway occurs when the dry rock mass fraction including sulfide is larger than 48 wt%, which is consistent with the geodetic constraints. Dehydration of serpentine has increase in total vol-ume of ~10

  5. Denitrification-coupled iron(ii) oxidation: a key process regulating the fate and transport of nitrate, phosphate, and arsenic in a wastewater-contaminated aquifer

    USGS Publications Warehouse

    Smith, Richard L.; Kent, Douglas B.; Repert, Deborah A.; Hart, C. P.

    2008-01-01

    Denitrification in the subsurface is often viewed as a heterotrophic process. However, some denitrifiers can also utilize inorganic electron donors. In particular, Fe(II), which is common in many aquifers, could be an important reductant for contaminant nitrate. Anoxic iron oxidation would have additional consequences, including decreased mobility for species like arsenic and phosphate, which bind strongly to hydrous Fe(III) oxide. A study was conducted in a wastewater contaminant plume on Cape Cod to assess the potential for denitrification- coupled Fe(II) oxidation. Previous changes in wastewater disposal upgradient of the study area had resulted in nitrate being transported into a portion of the anoxic zone of the plume and decreased concentrations of Fe(II), phosphate, and arsenic. A series of anoxic tracers (groundwater + nitrate + bromide) were injected into the unaffected, Fe(II)-containing zone under natural gradient conditions. Denitrification was stimulated within 1 m of transport (4 days) for both low and high (100 & 1000 μM) nitrate additions, initially producing stiochiometric quantities of nitrous oxide (>300 μM N) and trace amounts of nitrite. Subsequent injections at the same site reduced nitrate even more rapidly and produced less nitrous oxide, especially over longer transport distances. Fe(II) and nitrate concentrations decreased together and this was accompanied by an increase in colloidal Fe(III) and decreases in pH, total arsenic, and phosphate concentrations. All plume constituents returned to background levels several weeks after the tracer tests were completed. Groundwater microorganisms collected on filters during the tracer test rapidly and immediately reduced nitrite and oxidized Fe(II) in 3-hr laboratory incubations. Several pure cultures of Fe(II)-oxidizing denitrifying bacteria were isolated from core material and subsequently characterized. All of the isolates were mixotrophic, simultaneously oxidizing organic carbon and Fe

  6. Denitrification-Coupled Iron(II) Oxidation: A Key Process Regulating the Fate and Transport of Nitrate, Phosphate, and Arsenic in a Wastewater-Contaminated Aquifer

    NASA Astrophysics Data System (ADS)

    Smith, R. L.; Kent, D. B.; Repert, D. A.; Hart, C. P.

    2007-12-01

    Denitrification in the subsurface is often viewed as a heterotrophic process. However, some denitrifiers can also utilize inorganic electron donors. In particular, Fe(II), which is common in many aquifers, could be an important reductant for contaminant nitrate. Anoxic iron oxidation would have additional consequences, including decreased mobility for species like arsenic and phosphate, which bind strongly to hydrous Fe(III) oxide. A study was conducted in a wastewater contaminant plume on Cape Cod to assess the potential for denitrification- coupled Fe(II) oxidation. Previous changes in wastewater disposal upgradient of the study area had resulted in nitrate being transported into a portion of the anoxic zone of the plume and decreased concentrations of Fe(II), phosphate, and arsenic. A series of anoxic tracers (groundwater + nitrate + bromide) were injected into the unaffected, Fe(II)-containing zone under natural gradient conditions. Denitrification was stimulated within 1 m of transport (4 days) for both low and high (100 & 1000 μM) nitrate additions, initially producing stiochiometric quantities of nitrous oxide (>300 μM N) and trace amounts of nitrite. Subsequent injections at the same site reduced nitrate even more rapidly and produced less nitrous oxide, especially over longer transport distances. Fe(II) and nitrate concentrations decreased together and this was accompanied by an increase in colloidal Fe(III) and decreases in pH, total arsenic, and phosphate concentrations. All plume constituents returned to background levels several weeks after the tracer tests were completed. Groundwater microorganisms collected on filters during the tracer test rapidly and immediately reduced nitrite and oxidized Fe(II) in 3-hr laboratory incubations. Several pure cultures of Fe(II)-oxidizing denitrifying bacteria were isolated from core material and subsequently characterized. All of the isolates were mixotrophic, simultaneously oxidizing organic carbon and Fe

  7. A new type of a sol-gel-derived inorganic-organic nanocomposite

    SciTech Connect

    Kasemann, R.; Schmidt, H.K.; Wintrich, E.

    1994-12-31

    A new type of sol-gel-based transparent inorganic-organic nano composites has been developed by increasing the inorganic phase dimension to values just below the point, where scattering can be neglected. For this purpose, nanosized boehmite particles {le} < 50 nm are homogeneously incorporated in a sol based on tetraethoxysilane and an epoxysilane. The nanoscale boehmite particles act as catalysts for the polymerization of the epoxy silane to polyethylene oxide, as proved by {sup 13}C NMR, and are linked to the matrix by Si-O-Al bridges, as proven by {sup 27}Al-NMR spectroscopy. The synthesized sols can be applied by standard coating techniques on transparent polymers and are cured thermally. The mechanical properties (scratch resistance, hardness) have been substantially improved compared to systems with molecular dimensions of the inorganic phase. The effect is attributed to the special structure of flexibly suspended nano-scale boehmite particles in an inorganic-organic network by a tailored interface.

  8. 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

  9. 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

  10. 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.).

  11. 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.

  12. 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)

  13. 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.

  14. 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. PMID:21361349

  15. Dynamics of three-dimensional hydrous thermal-chemical plumes in the mantle wedge

    NASA Astrophysics Data System (ADS)

    Zhu, Guizhi; Gerya, Taras; Kaus, Boris; Tackley, Paul; Honda, Satoru; Yoshida, Takeyoshi; Yuen, David; Connolly, James

    2010-05-01

    As a plate subducts, fluid release from the subducting slab lowers the melting point of the surrounding mantle, which results in the configuration of more dense and viscous dry mantle overlying a thin layer of hydrated mantle with lowered density and viscosity. These processes trigger Rayleigh-Taylor (RT) type instabilities in a low-viscosity wedge with complex three-dimensional (3-D) geometries. RT-type cold plumes atop the slab were previously studied in 2-D. Here we use 3-D petrological-thermomechanical numerical simulations to investigate the dynamics of 3-D hydrous thermal-chemical plumes in the mantle wedge. The simulations were carried out with the I3ELVIS code which is based on a multigrid approach combined with marker-in-cell methods and conservative finite difference schemes. Our numerical simulations show that three types of upwelling plumes occur above the slab-mantle interface: (1) finger-like plumes forming roll/sheet-like structures parallel to the trench; (2) ridge-like structures perpendicular to the trench; and (3) flattened, wave-like instabilities propagating upward along the upper surface of the slab and forming zigzag patterns parallel to the trench. Plume-related melt productivity correlates well with volcanic activity clustering in natural intraoceanic arcs, such as in northeast Japan. Why do the above different plume patterns form atop the slab? Variation in partially molten rock viscosity notably affects plume patterns and lateral dimensions: wave-like plumes are most pronounced at higher (10^19 Pa s) viscosity, which also favors the development of larger plumes compared to models with lower (10^18 Pa s) viscosity. The "effective" density contrast between solid and molten rocks, which is closely related to melt extraction processes, is the key factor in determining plume patterns. A large to moderate density contrast of >200 kg/m3 (i.e. low to moderate degree of melt extraction) promotes the development of three distinct patterns of the

  16. The role of Iron on the dissolution of Sulfur in hydrous silicate melts

    NASA Astrophysics Data System (ADS)

    Klimm, K.; Kohn, S. C.; Botcharnikov, R. E.

    2012-04-01

    It is well established that the sulfur solubility in silicate melts is a function of fO2 and melt compositions [1]. At high fO2, S6+ is dominant and more soluble in natural silicate melts than S2-, which is dominant at low fO2. Primitive melt compositions such as basalt can contain an order of magnitude more sulfur than more evolved melt compositions such as rhyolite. The compositional control on the sulfur solubility is yet not fully understood but a positive correlation with FeO has often been observed. Thus, determining the S2-- and S6+-speciesincorporated in the silicate glass structure is crucial to unravel the sulfur dissolution mechanism in silicate melts. Together with solubility measurements such information is essential to quantify the sulfide and sulfate capacity of silicate melts and to understand the sulfur flux in subduction zones. Here we present Raman and XANES measurements on experimentally equilibrated sulfur-bearing, hydrous silicate glasses, including soda-lime (SLG), K2Si4O9 (KSG), albite and trondhjemite (TROND) compositions. A series of SLG and KSG glasses, doped with small quantities of Fe, were also studied in order to determine the effect of Fe/S on the S solubility. The experiments were performed in internally heated and cold seal pressure vessels at 200 MPa, 1000 and 850 ° C and fO2 ranging from logfO2 = QFM-2.4 to QFM+4. The systematic correlation of features in Raman and XANES spectra allows the identification of at least four different S-species in the glasses depending on fO2 and Fe/S of the system. In Fe-free melts S is dissolved as SH-, H2S and/or SO42- depending on the prevailing fO2. S2- is more soluble than S6+.The total sulfur solubility depends on the degree of polymerisation of the melt and increases with increasing NBO/T. This correlation is much more pronounced for SH- and H2S than for SO42-. Adding Fe results in the formation of Fe-S-complexes at the expense of SH- and H2S, which are still observed up to Fe/S ~ 2.6. The S

  17. 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

  18. 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.

  19. 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

  20. 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).

  1. 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.

  2. 29 CFR 1910.1018 - Inorganic arsenic.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 6 2012-07-01 2012-07-01 false Inorganic arsenic. 1910.1018 Section 1910.1018 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) OCCUPATIONAL SAFETY AND HEALTH STANDARDS (CONTINUED) Toxic and Hazardous Substances § 1910.1018 Inorganic arsenic. (a) Scope...

  3. 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...

  4. 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...

  5. 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...

  6. 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...

  7. 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...

  8. REMOVING DISSOLVED INORGANIC CONTAMINANTS FROM WATER

    EPA Science Inventory

    Dissolved inorganic contaminants in water can be cationic, anionic, or neutral forms of ions, atoms, or molecules of any element in the periodic table. The article describes the physicochemical treatment processes typically used to remove the more common inorganic contaminants fr...

  9. 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...

  10. 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...

  11. 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...

  12. 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...

  13. 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...

  14. 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...

  15. 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...

  16. 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...

  17. 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...

  18. 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...

  19. 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.

  20. Inorganic nanotubes and fullerene-like materials.

    PubMed

    Tenne, Reshef

    2002-12-01

    Following the discovery of fullerenes and carbon nanotubes, it was shown that nanoparticles of inorganic layered compounds, like MoS2, are unstable in the planar form and they form closed cage structures with polyhedral or nanotubular shapes. Various issues on the structure, synthesis, and properties of such inorganic fullerene-like structures are reviewed, together with some possible applications. PMID:12432497

  1. 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.

  2. Determination of the hydrogen isotopic compositions of organic materials and hydrous minerals using thermal combustion laser spectroscopy.

    PubMed

    Koehler, Geoff; Wassenaar, Leonard I

    2012-04-17

    Hydrogen isotopic compositions of hydrous minerals and organic materials were measured by combustion to water, followed by optical isotopic analysis of the water vapor by off-axis integrated cavity output spectroscopy. Hydrogen and oxygen isotopic compositions were calculated by numerical integration of the individual isotopologue concentrations measured by the optical spectrometer. Rapid oxygen isotope exchange occurs within the combustion reactor between water vapor and molecular oxygen so that only hydrogen isotope compositions may be determined. Over a wide range in sample sizes, precisions were ±3-4 per mil. This is comparable but worse than continuous flow-isotope ratio mass spectroscopy (CF-IRMS) methods owing to memory effects inherent in water vapor transfer. Nevertheless, the simplicity and reduced cost of this analysis compared to classical IRMS or CF-IRMS methods make this an attractive option to determine the hydrogen isotopic composition of organic materials where the utmost precision or small sample sizes are not needed. PMID:22432837

  3. 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.

  4. Hydrogen concentration in plagioclaes as a hygrometer of magmas: Approaches from melt inclusion analyses and hydrous melting experiments

    NASA Astrophysics Data System (ADS)

    Hamada, M.; Ushioda, M.; Fujii, T.; Takahashi, E.

    2012-12-01

    Plagioclase is one of the nominally anhydrous minerals (NAMs) which accommodates hundreds wt. ppm of hydrogen. Hydrogen in igneous plagioclase (OH) can act as a proxy of dissolved H2O in silicate melt. In order to use it as a practical hygrometer of magmas, we studied partitioning of hydrogen between plagioclase and basaltic melt dis-solving H2O (0.3˜5.5 wt.%) by two approaches: analyses of plagioclase-hosted melt inclusions (H2O≈0.3 wt.%) from mid-ocean ridge basalt (MORB) and hydrogen partitioning experiments between An96 plagioclase and hydrous basaltic melt (0.8 wt.%≦H2O≦5.5 wt.%) at 0.35 GPa. Concentration hydrogen in plagioclase and concentration of H2O in basaltic glasses were analyzed by infrared spectroscopy. As a first series of this study, plagioclase-hosted melt inclusions in MORB (50.5% SiO2, 15.1% Al2O3, 7.4% MgO) from the Rodriguez triple junction in the Indian Ocean were analyzed. The hydrogen concentration of plagioclase is less than 50 wt. ppm water, and no correlation between hydrogen concentration and anorthite content is recognized. Average H2O concentrations in melt inclusions is 0.3 wt.%. Therefore, apparent partition coefficient of hydrogen between plagioclase and melt is ≈ 0.01 in molar basis. As a second series of this study, hydrous melting experiments of arc basaltic magma were performed at 350 MPa using internally-heated pressure vessel. Starting material was hydrous glass (0.8 wt.%≦H2O≦5.5 wt.%) of an undifferentiated rock from Miyakejima volcano, a frontal-arc volcano in Izu-arc (MTL rock: 50.5% SiO2, 18.1% Al2O3, 4.9% MgO). A grain of Ca-rich plagioclase (≈1 mg, about An96) and 10 mg of powdered glasses were sealed in Au80Pd20 alloy capsule, and then kept at temperature at around the liquidus. Liquidus phase of MTL rock at 350 MPa is always plagioclase with 0 to 5.5 wt.% H2O in melt, and therefore, a grain of plagioclase and hydrous melt were nearly in equilibrium. Oxygen fugacity (fO2) during the melting experiments

  5. 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

  6. Hydrous state of the subducting Philippine Sea plate inferred from receiver function image using onshore and offshore data

    NASA Astrophysics Data System (ADS)

    Akuhara, Takeshi; Mochizuki, Kimihiro

    2015-12-01

    Exploring the hydrous state of subducting oceanic crust is intriguing because it is considered to affect the strength of megathrust faults that cause various types of earthquakes; however, its state beneath offshore regions remains unclear. In this study, we investigated fluid contents along the subducting Philippine Sea plate around the Kii Peninsula by receiver function (RF) analysis using data from both on-land stations and ocean bottom seismometers (OBSs). The vertical component of OBS records contains dominant water reverberations, and thus, conventional methods fail to estimate RFs correctly. We therefore developed a method to calculate RFs that removes such reverberations. The RFs calculated by our method showed considerable improvement for later phase identification, compared with those obtained using a conventional method. Resultant RF amplitudes suggest the existence of low-velocity zones directly beneath the plate interface of both onshore and offshore regions. We interpreted this as evidence of hydrous oceanic crust, which extends from 5 km to 35 km depth to the plate interface. Reduction of RF amplitudes beneath the Kii Peninsula suggests that dehydration of the oceanic crust increases the seismic velocity, and the accompanying densification makes the plate interface permeable. This permeable plate interface may characterize the location of non-volcanic tremors. This contrasts with long-term slow slip events because it is believed that they occur along the sealed plate interface. Comparison between the plate geometry and local earthquakes reveals the paucity of earthquakes in the oceanic crust below a certain depth, which provides further insight into the dehydration process in the oceanic crust.

  7. 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.

  8. 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.

  9. SHRNA-MEDIATED SILENCING OF AS3MT EXPRESSION MODULATES THE CAPACITY OF HEPG2 CELLS TO METHYLATE INORGANIC ARSENIC

    EPA Science Inventory

    Several methyltransferases have been linked to the oxidative methylation of inorganic arsenic (iAs) in mammalian cells. However, the relative contributions of these enzymes to the overall capacity of cells to methylate iAs have not been characterized. Arsenic (+3 oxidation state)...

  10. 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...

  11. METABOLISM AS A DETERMINING FACTOR IN ACUTE AND CHRONIC TOXICITY OF INORGANIC ARSENIC

    EPA Science Inventory

    The metabolism of inorganic arsenic (iAs) in humans involves reduction of As(V)-species to trivalency and oxidative methylation of As(III)-species. In this pathway, iAs is converted to methylarsenic (MAs) and dimethyl arsenic (DMAs) metabolites that contain As(III) or As(V). Rec...

  12. Inorganic polymers: morphogenic inorganic biopolymers for rapid prototyping chain.

    PubMed

    Müller, Werner E G; Schröder, Heinz C; Shen, Zhijian; Feng, Qingling; Wang, Xiaohong

    2013-01-01

    In recent years, considerable progress has been achieved towards the development of customized scaffold materials, in particular for bone tissue engineering and repair, by the introduction of rapid prototyping or solid freeform fabrication techniques. These new fabrication techniques allow to overcome many problems associated with conventional bone implants, such as inadequate external morphology and internal architecture, porosity and interconnectivity, and low reproducibility. However, the applicability of these new techniques is still hampered by the fact that high processing temperature or a postsintering is often required to increase the mechanical stability of the generated scaffold, as well as a post-processing, i.e., surface modification/functionalization to enhance the biocompatibility of the scaffold or to bind some bioactive component. A solution might be provided by the introduction of novel inorganic biopolymers, biosilica and polyphosphate, which resist harsh conditions applied in the RP chain and are morphogenetically active and do not need supplementation by growth factors/cytokines to stimulate the growth and the differentiation of bone-forming cells. PMID:24420716

  13. 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

  14. Synthesis and characterization of inorganic materials precipitated into polymeric and novel liquid crystalline systems

    NASA Astrophysics Data System (ADS)

    Lubeck, Christopher Ryan

    The use of nanostructured, hybrid materials possesses great future potential. Many examples of nanostructured materials exist within nature, such as animal bone, animal teeth, and seashells. This research, inspired by nature, strove to mimic salient properties of natural materials, utilizing methods observed within nature to produce materials. Further, this research increased the functionality of the templates from "mere" template to functional participant. Different chemical methods to produce hybrid materials were employed within this research to achieve these goals. First, electro-osmosis was utilized to drive ions into a polymeric matrix to form hybrid inorganic polymer material, creating a material inspired by naturally occurring bone or seashell in which the inorganic component provides strength and the polymeric material decreases the brittleness of the combined hybrid material. Second, self-assembled amphiphiles, forming higher ordered structures, acted as a template for inorganic cadmium sulfide. Electronically active molecules based on ethylene oxide and aniline segments were synthesized to create interaction between the templating material and the resulting inorganic cadmium sulfide. The templating process utilized self-assembly to create the inorganic structure through the interaction of the amphiphiles with water. The use of self-assembly is itself inspired by nature. Self-assembled structures are observed within living cells as cell walls and cell membranes are created through hydrophilic and hydrophobic interactions. Finally, the mesostructured inorganic cadmium sulfide was itself utilized as a template to form mesostructured copper sulfide.

  15. Low temperature removal of inorganic sulfur compounds from mining process waters.

    PubMed

    Liljeqvist, Maria; Sundkvist, Jan-Eric; Saleh, Amang; Dopson, Mark

    2011-06-01

    Process water and effluents from mining operations treating sulfide rich ores often contain considerable concentrations of metastable inorganic sulfur compounds such as thiosulfate and tetrathionate. These species may cause environmental problems if released to downstream recipients due to oxidation to sulfuric acid catalyzed by acidophilic microorganisms. Molecular phylogenic analysis of the tailings pond and recipient streams identified psychrotolerant and mesophilic inorganic sulfur compound oxidizing microorganisms. This suggested year round thiosalt oxidation occurs. Mining process waters may also contain inhibiting substances such as thiocyanate from cyanidation plants. However, toxicity experiments suggested their expected concentrations would not inhibit thiosalt oxidation by Acidithiobacillus ferrivorans SS3. A mixed culture from a permanently cold (4-6 °C) low pH environment was tested for thiosalt removal in a reactor design including a biogenerator and a main reactor containing a biofilm carrier. The biogenerator and main reactors were successively reduced in temperature to 5-6 °C when 43.8% of the chemical oxidation demand was removed. However, it was found that the oxidation of thiosulfate was not fully completed to sulfate since low residual concentrations of tetrathionate and trithionate were found in the discharge. This study has demonstrated the potential of using biotechnological solutions to remove inorganic sulfur compounds at 6°C and thus, reduce the impact of mining on the environment. PMID:21280027

  16. Shape control of inorganic nanoparticles from solution

    NASA Astrophysics Data System (ADS)

    Wu, Zhaohui; Yang, Shuanglei; Wu, Wei

    2016-01-01

    Inorganic materials with controllable shapes have been an intensely studied subject in nanoscience over the past decades. Control over novel and anisotropic shapes of inorganic nanomaterials differing from those of bulk materials leads to unique and tunable properties for widespread applications such as biomedicine, catalysis, fuels or solar cells and magnetic data storage. This review presents a comprehensive overview of shape-controlled inorganic nanomaterials via nucleation and growth theory and the control of experimental conditions (including supersaturation, temperature, surfactants and secondary nucleation), providing a brief account of the shape control of inorganic nanoparticles during wet-chemistry synthetic processes. Subsequently, typical mechanisms for shape-controlled inorganic nanoparticles and the general shape of the nanoparticles formed by each mechanism are also expounded. Furthermore, the differences between similar mechanisms for the shape control of inorganic nanoparticles are also clearly described. The authors envision that this review will provide valuable guidance on experimental conditions and process control for the synthesis of inorganic nanoparticles with tunable shapes in the solution state.

  17. Inorganic membranes and solid state sciences

    NASA Astrophysics Data System (ADS)

    Cot, Louis; Ayral, André; Durand, Jean; Guizard, Christian; Hovnanian, Nadine; Julbe, Anne; Larbot, André

    2000-05-01

    The latest developments in inorganic membranes are closely related to recent advances in solid state science. Sol-gel processing, plasma-enhanced chemical vapor deposition and hydrothermal synthesis are methods that can be used for inorganic membrane preparation. Innovative concepts from material science (templating effect, nanophase materials, growing of continuous zeolite layers, hybrid organic-inorganic materials) have been applied by our group to the preparation of inorganic membrane materials. Sol-gel-derived nanophase ceramic membranes are presented with current applications in nanofiltration and catalytic membrane reactors. Silica membranes with an ordered porosity, due to liquid crystal phase templating effect, are described with potential application in pervaporation. Defect-free and thermally stable zeolite membranes can be obtained through an original synthesis method, in which zeolite crystals are grown inside the pores of a support. Hybrid organic-inorganic materials with permselective properties for gas separation and facilitated transport of solutes in liquid media, have been successfully adapted to membrane applications. Potential membrane developments offered by CVD deposition techniques are also illustrated through several examples related to the preparation of purely inorganic and hybrid organic-inorganic membrane materials.

  18. Nanowire-haired inorganic membranes with superhydrophilicity and underwater ultralow adhesive superoleophobicity for high-efficiency oil/water separation.

    PubMed

    Zhang, Feng; Zhang, Wen Bin; Shi, Zhun; Wang, Dong; Jin, Jian; Jiang, Lei

    2013-08-14

    A novel all-inorganic Cu(OH)2 nanowire-haired membrane with superhydrophilicity and underwater ultralow adhesive superoleophobicity is fabricated by a facile surface oxidation of copper mesh that allows effective separation of both immiscible oil/water mixtures and oil-in-water emulsions solely driven by gravity, with extremely high separation efficiency. The all-inorganic membrane exhibits superior solvent and alkaline resistance and antifouling property compared to organic-based membranes. PMID:23788392

  19. The quest for inorganic fullerenes

    DOE PAGESBeta

    Pietsch, Susanne; Dollinger, Andreas; Strobel, Christoph H.; Park, Eun Ji; Ganteför, Gerd; Seo, Hyun Ook; Kim, Young Dok; Idrobo, Juan-Carlos; Pennycook, Stephen J.

    2015-10-02

    Experimental results of the search for inorganic fullerenes are presented. Mo nSm - and WnSm - clusters are generated with a pulsed arc cluster ion source equipped with an annealing stage. This is known to enhance fullerene formation in the case of carbon. Analogous to carbon, the mass spectra of the metal chalcogenide clusters produced in this way exhibit a bimodal structure. Moreover, the species in the first maximum at low mass are known to be platelets. The structure of the species in the second maximum is studied by anion photoelectron spectroscopy, scanning transmission electron microscopy, and scanning tunneling microcopy.more » All experimental results indicate a two-dimensional structure of these species and disagree with a three-dimensional fullerene-like geometry. A possible explanation for this preference of two-dimensional structures is the ability of a two-element material to saturate the dangling bonds at the edges of a platelet by excess atoms of one element. A platelet consisting of a single element only cannot do this. Likewise, graphite and boron might be the only materials forming nano-spheres because they are the only single element materials assuming two-dimensional structures.« less

  20. The quest for inorganic fullerenes

    SciTech Connect

    Pietsch, Susanne; Dollinger, Andreas; Strobel, Christoph H.; Ganteför, Gerd E-mail: ydkim91@skku.edu; Park, Eun Ji; Kim, Young Dok E-mail: ydkim91@skku.edu; Seo, Hyun Ook; Pennycook, Stephen J.

    2015-10-07

    Experimental results of the search for inorganic fullerenes are presented. Mo{sub n}S{sub m}{sup −} and W{sub n}S{sub m}{sup −} clusters are generated with a pulsed arc cluster