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Sample records for hydrous oxide inorganic

  1. 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.

  2. 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.

  3. Preparation and properties of coated, uniform, inorganic colloidal particles: I. Aluminum (hydrous) oxide on hematite, chromia, and titania

    SciTech Connect

    Kratohvil, S.; Matijevic, E. )

    1987-10-01

    Spherical alumina (hydrous) oxide particles of narrow size distribution were prepared by first hydrolyzing aluminum sulfate solutions at elevated temperatures in the presence of urea. The system was quenched before any solids were formed. Dilution of the prepared solutions at room temperature led to sol formation. The same procedure produced surface coatings on admixed, preformed solid particles. Uniform hematite, chromium hydroxide, and titania were used as core materials. The thickness of the coatings could be varied by proper adjustment of the concentrations of particles, aluminum salt solutions, and reaction time.

  4. 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.

  5. 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.

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

    PubMed

    Pommerenk, Peter; Schafran, Gary C

    2005-09-01

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

  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. Inorganic particulates in removal of heavy metal toxic ions IX. Rapid and efficient removal of Hg(II) by hydrous manganese and tin oxides.

    PubMed

    Mishra, Shuddhodan P; Dubey, Som Shankar; Tiwari, Diwakar

    2004-11-01

    Batch studies have been carried out in the removal of Hg(II) from aqueous solutions by using well-synthesized and -characterized hydrous manganese oxide (HMO) and hydrous tin oxide (HTO) employing a radiotracer technique. Results obtained reveal that increased sorptive concentration (10(-8)-10(-2) mol dm(-3)), temperature (298-328 K), and pH (ca. 2.0-10.5) enhance the removal efficiency of these solids. First-order uptake of Hg(II) on HMO and HTO follows the Freundlich adsorption isotherm for entire concentration range. Positive values of DeltaH0 for the uptake process on both solids indicate endothermic uptake and desorption experiments point to irreversible uptake. Radiation stability of the adsorbents has also been assessed using a 300-mCi (Ra-Be) neutron source having an integral neutron flux of 3.85 x 10(6) N cm(-2) s(-1) and associated with a nominal gamma-dose of ca. 1.72 Gy/h.

  9. 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.

  10. 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.

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

    SciTech Connect

    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.

  12. 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.

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

    DOEpatents

    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.

  14. 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.

  15. 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.

  16. 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.

  17. Development of hydrous titanium oxide catalysts for upgrading coal liquids

    SciTech Connect

    Lott, S.; Dosch, R.

    1993-07-01

    Improved efficiency in direct coal liquefaction processes can be obtained by developing catalysts with better activity, selectivity, and life. In previous exploratory research at Sandia National Laboratories, catalysts prepared via hydrous metal oxide (HMO) ion exchangers have been shown to have potential for application to a number of reactions associated with the conversion of coal to liquid fuels. In the present effort, one member of this class of catalysts, hydrous titanium oxide (HTO), has been developed for use in hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) of coal liquids. The unsupported (or bulk) NiMo-HTO catalyst performed well for HDS/HDN of a coal derived liquid as compared to the benchmark Shell 324 catalyst. The CoMo-HTO, while performing better than the Shell 324 catalyst, did not perform quite as well as the NiMo-HTO. In a side-by-side comparison of supported NiMo-HTO catalysts with commercial counterparts, the supported NiMo-HTO catalysts outperformed the Shell 324 and Amocat 1C catalysts on a weight of Mo basis. On a catalyst weight basis, the NiMo-HTO coated catalyst on a Shell 324 blank under performed Shell 324, while the NiMo-HTO coated catalyst on an Amocat 1C support performed as well as the Amocat 1C catalyst.

  18. 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.

  19. 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.

  20. 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.

  1. Kinetics of oxytetracycline reaction with a hydrous manganese oxide.

    PubMed

    Rubert, Kennedy F; Pedersen, Joel A

    2006-12-01

    Tetracycline antibiotics comprise a class of broad spectrum antimicrobial agents finding application in human therapy, animal husbandry, aquaculture, and fruit crop production. To better understand the processes affecting these antibiotics in soils and sediments, the kinetics of oxytetracycline transformation by a hydrous manganese oxide (MnO2) were investigated as a function of reactant concentration, pH, and temperature. Oxytetracycline was rapidly degraded by MnO2. Initial reaction rates exhibited pronounced pH-dependence, increasing as pH decreased. Reaction of oxytetracycline with MnO2 was accompanied by generation of Mn(II) ions, suggesting oxidative transformation of the antibiotic. At pH 5.6, apparent reaction orders for oxytetracycline and MnO2 were 0.7 and 0.8. Reaction order with respect to H+ was 0.6 between pH 4 and 9. Initial reaction rates increased by a factor of approximately 2.4 for 10 degrees C temperature increases; the apparent activation energy (60 kJ x mol(-1)) was consistent with a surface-controlled reaction. Reactivity of tetracycline antibiotics toward MnO2 increased in the following order: rolitetracyline oxytetracycline < or =tetracycline approximately meclocycline < chlortetracycline. The initial rate of chlortetracycline degradation by MnO2 was substantially larger than that of the other tetracycline antibiotics investigated. MnO2 reactivity toward oxytetracycline decreased with time; a retarded rate equation was used to describe oxytetracycline reaction with MnO2 under declining rate conditions. This study indicates that natural manganese oxides in soils and sediments are likely to promote appreciable degradation of tetracycline antibiotics, and that reaction rates are strongly dependent on reaction time scale and solution conditions.

  2. 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.

  3. Inorganic Halogen Oxidizers.

    DTIC Science & Technology

    1984-02-22

    this series of compounds is needed to verify this effect. The F NMR spectra of these salts were recorded in an- hydrous HF solutions at 29 °C. In...The yield of only 55% for CIF6BF4 can be attributed to the following factors: (i) hang-up of some mother liquor on »he filter cake; (ii) possibly...basis of NF4HF:. With most of ’me Ni4Ili2 * allies losi being due lo hang up of some mother liquor on the CsSbF6 filter cake during the metathc teal

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

    PubMed

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

    2012-07-01

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

  5. 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...

  6. 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.

  7. 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.

  8. Pd oxides/hydrous oxides as highly efficient catalyst for formic acid electrooxidation

    NASA Astrophysics Data System (ADS)

    Yan, Liang; Yao, Shikui; Chang, Jinfa; Liu, Changpeng; Xing, Wei

    2014-03-01

    A novel Pd-based catalyst for formic acid electrooxidation (FAEO) was prepared by annealing commercial Pd/C catalyst under the O2 atmosphere at 100 °C, which exhibits excellent catalytic activity and stability for FAEO due to introduction of Pd oxides/hydrous oxides (POHOs). The catalytic activity of the as-prepared catalyst towards FAEO is 1.86 times of the commercial Pd/C catalyst in 0.5 M H2SO4 + 0.5 M HCOOH solution. Chronoamperometric curves show obvious improvement of the as-prepared catalyst electrocatalytic stability for FAEO. It is confirmed that POHOs can provide the required oxygen species for intermediate CO oxidation during the oxidation process of formic acid.

  9. Inorganic Halogen Oxidizer Research

    DTIC Science & Technology

    1975-02-26

    KEY WORDS (Continue on reverse aide il necesxary and identity by block number) Synthesis, Novel Oxidizers, Perchlorates, Fluorination , Halogen...C. J. Schack, R. D. Wilson, and E. C. Curtis, 5th European Fluorine Symposium, Avie.nore, Scotland (September 1974) 20. "New Energetic Halogen...elimination lasers. For NF-, no evidence for protonation was found at tempera- tures as low as -78 C. Furthermore, attempts to fluorinate NH. AsF

  10. Sol gel synthesis of hydrous ruthenium oxide nanonetworks from 1,2-epoxides

    NASA Astrophysics Data System (ADS)

    Walker, Jeremy; Bruce King, R.; Tannenbaum, Rina

    2007-08-01

    Hydrous ruthenium oxide (RuO 2· xH 2O) xerogels were synthesized through the addition of a 1,2-epoxide, propylene oxide, to commercial hydrated ruthenium chloride, "RuCl 3· xH 2O," in ethanol. After a blue-black monolithic gel formed in 4 h, the samples were allowed to age for 24 h and were dried in ambient conditions. The dried samples were then characterized by XPS, XRD, DTA and TGA. XPS showed the Ru(3 d5/2) peak at a binding energy of 281.7 eV, corresponding to that of hydrous ruthenium oxide. XRD data revealed the synthesized material as amorphous. Heating the sample in inert atmospheres caused the complete reduction of the oxide to the zero-valent state, whereas heating the sample in air resulted in both crystalline anhydrous RuO 2 and zero-valent ruthenium, depending on the method of heating. DTA traces showed an endotherm ending at 150 °C, corresponding to the loss of coordinated water, as well as two higher temperature crystallization exotherms when the sample was heated in both inert and oxygen-rich atmospheres. TGA runs also confirmed the complete reduction of the hydrous oxide when heated in nitrogen below 270 °C and the formation of anhydrous ruthenium oxide when heated in air, confirming the XRD results.

  11. Sol-gel synthesis of hydrous ruthenium oxide nanonetworks from 1,2-epoxides

    SciTech Connect

    Walker, Jeremy; Bruce King, R.; Tannenbaum, Rina

    2007-08-15

    Hydrous ruthenium oxide (RuO{sub 2}.xH{sub 2}O) xerogels were synthesized through the addition of a 1,2-epoxide, propylene oxide, to commercial hydrated ruthenium chloride, 'RuCl{sub 3}.xH{sub 2}O,' in ethanol. After a blue-black monolithic gel formed in 4 h, the samples were allowed to age for 24 h and were dried in ambient conditions. The dried samples were then characterized by XPS, XRD, DTA and TGA. XPS showed the Ru(3d{sub 5/2}) peak at a binding energy of 281.7 eV, corresponding to that of hydrous ruthenium oxide. XRD data revealed the synthesized material as amorphous. Heating the sample in inert atmospheres caused the complete reduction of the oxide to the zero-valent state, whereas heating the sample in air resulted in both crystalline anhydrous RuO{sub 2} and zero-valent ruthenium, depending on the method of heating. DTA traces showed an endotherm ending at 150 deg. C, corresponding to the loss of coordinated water, as well as two higher temperature crystallization exotherms when the sample was heated in both inert and oxygen-rich atmospheres. TGA runs also confirmed the complete reduction of the hydrous oxide when heated in nitrogen below 270 deg. C and the formation of anhydrous ruthenium oxide when heated in air, confirming the XRD results. - Graphical abstract: Heating of hydrous ruthenium oxide, RuO{sub 2}.xH{sub 2}O, under an inert atmosphere, results in its complete reduction to the zero-valent state, whereas heating it in air results in both crystalline anhydrous RuO{sub 2} and zero-valent ruthenium, depending on the method of heating.

  12. 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.

  13. Electrochemical capacitor performance of hydrous ruthenium oxide/mesoporous carbon composite electrodes

    NASA Astrophysics Data System (ADS)

    Jang, Jong H.; Han, Sangjin; Hyeon, Taeghwan; Oh, Seung M.

    Ruthenium/carbon composite materials are prepared by impregnating ruthenium(III) acetylacetonate into a mesoporous carbon (average pore diameter=12 mn, pore volume=3.6 cm 3 g -1) and then heat treatment at 320 °C for 2 h under an argon atmosphere. The metallic ruthenium nanoparticles are converted to pseudo-capacitive hydrous ruthenium oxide by electrochemical oxidation at 0.75 V (versus SCE) for 2 h in 2.0 M H 2SO 4. The specific capacitance of the composite electrodes, which is the sum of the double-layer capacitance of mesoporous carbon and the pseudo-capacitance of hydrous ruthenium oxide, reaches 243 F g -1 with heavy loading. As the loading is increased, however, the degree of ruthenium utilization for a pseudo-capacitor becomes poorer, presumably due to a limited conversion to the hydrous oxide form. The rate capability of composite electrodes also decreases with increase in ruthenium loading, due to an increase in both the equivalent series resistance (ESR) and the overall capacitance value. The ESR enlargement is caused mainly an increase in the electrolyte resistance within pores which, in turn, results from a pore narrowing with ruthenium loading Hindered ionic motion in narrowed pores can explain this feature. An increase in the RC time constant with ruthenium loading is further verified by ac impedance measurements.

  14. 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.

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

    PubMed

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

    2016-02-01

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

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

    USGS Publications Warehouse

    Hem, J.D.

    1977-01-01

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

  17. Quartz and Hydrous Iron-oxide Impactites from the Bee Bluff Structure of South Texas

    NASA Astrophysics Data System (ADS)

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

    2005-07-01

    Breccia impactite samples are found to have been strongly influenced by high pressure shock waves controlled by the thin veneer of sandstone, siltstone and a thin layer of iron-rich siltstone target rocks. Carrizo sandstone is converted to a hard grey breccia containing comminuted quartz bound with tightly adhering alpha goethite. Transformations in the hydrous iron-oxide binder and hydrous iron-rich siltstone in virtually all impactite samples dominate the scientific issues. Goethite is found in numerous samples including spherules loose on the site, `sky bombs,' in suevite in a Rosetta Stone containing five different impactite clasts, and in samples with hydrodynamic instabilities. Localized melting in quartz at particle interfaces is observed throughout. SEM and EDX analysis shows regions of fused quartz, some in the ballen structure characteristic of lechatleriete. Acicular goethite nanocrystals and submicron spheres are abundant. The high pressure-high temperature pulse of the impact produces an environment in which transformation to the iron-rich hydrous oxide to goethite, hematite and steam is to be expected.

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

    SciTech Connect

    Collins, Jack Lee; Pye, S. L.

    2009-02-01

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

  19. 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.

  20. 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.

  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. 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.

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

    SciTech Connect

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

    2001-04-01

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

  4. [Sorption-desorption of phosphate in wastewater by hydrous iron oxide].

    PubMed

    Xiang, Xue-Min; Liu, Ying; Zhou, Ji-Ti; Wang, Ren

    2008-11-01

    FeCl3 was used t o prepare hydrous iron oxide (HIO) as a n absorbent for phosphate (P) sorption and desorption study. The results showed that as pH decreased, the sorption capacity of HIO increased, and the sorption kinetics followed the second-order model, and the sorption isotherm could be fitted by the Langmuir equation. A 50 g/L NaOH solution was used for desorption of P from HIO, and the desorption rate could be reached over 98% . No relation was found between desorption rate and adsorption capacity. Based on above results, HIO was applied to adsorption of P from supernatant of sludge thickener, and after desorption, more than 90% of P was recovered. According to the results obtained, an effective system for P removal and recovery from municipal wastewater was suggested, which includes the following processes: adsorption, desorption, regeneration of HIO, and of recovery of P from P-rich desorption solution.

  5. 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.

  6. 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

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

    NASA Astrophysics Data System (ADS)

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

    2016-09-01

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

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

    PubMed Central

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

    2016-01-01

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

  9. 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

  10. Removal of fluoride by hydrous manganese oxide-coated alumina: performance and mechanism.

    PubMed

    Teng, Shao-Xiang; Wang, Shu-Guang; Gong, Wen-Xin; Liu, Xian-Wei; Gao, Bao-Yu

    2009-09-15

    A novel hydrous-manganese-oxide-coated alumina (HMOCA) material was prepared through a redox process. The adsorbent was characterized by SEM, BET surface area measurement, XRD, pH(PZC) measurement, FTIR spectroscopy, and XPS. The manganese oxides were amorphous and manganese existed mainly in the +IV oxidation state. Batch and column experiments were carried out to investigate the adsorption potential of the adsorbent. Fluoride adsorption onto HMOCA followed the pseudo-second-order equation well with a correlation coefficient greater than 0.99. Both external and intraparticle diffusion contributed to the rate of transfer and removal. The adsorption of fluoride was thought to take place mainly by ion-exchange. Optimum removal of fluoride occurred in a pH range of 4.0-6.0. The maximum adsorption capacity calculated from the Langmuir model was 7.09 mg/g. The presence of HCO(3)(-), SO(4)(2-) and PO(4)(3-) had negative effects on the adsorption of fluoride. The adsorbed fluoride can be released by alkali solution. Column studies were performed and 669 bed volumes were treated with the effluent fluoride under 1.0mg/L at an influent F(-) concentration of 5.0mg/L and flow rate of 2.39 m(3)/(m(2)h) (empty bed contact time=7.5 min).

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

    SciTech Connect

    Collins, Jack Lee; Chi, Anthony

    2009-02-01

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

  12. Enhanced removal of As (V) from aqueous solution using modified hydrous ferric oxide nanoparticles

    PubMed Central

    Huo, Lijuan; Zeng, Xibai; Su, Shiming; Bai, Lingyu; Wang, Yanan

    2017-01-01

    Hydrous ferric oxide (HFO) is most effective with high treatment capacity on arsenate [As(V)] sorption although its transformation and aggregation nature need further improvement. Here, HFO nanoparticles with carboxymethyl cellulose (CMC) or starch as modifier was synthesized for the purpose of stability improvement and As(V) removal from water. Comparatively, CMC might be the optimum stabilizer for HFO nanoparticles because of more effective physical and chemical stability. The large-pore structure, high surface specific area, and the non-aggregated nature of CMC-HFO lead to increased adsorption sites, and thus high adsorption capacities of As(V) without pre-treatment (355 mg·g−1), which is much greater than those reported in previous studies. Second-order equation and dual-mode isotherm model could be successfully used to interpret the sorption kinetics and isotherms of As(V), respectively. FTIR, XPS and XRD analyses suggested that precipitation and surface complexation were primary mechanisms for As(V) removal by CMC modified HFO nanoparticles. A surface complexation model (SCM) was used to simulate As adsorption over pH 2.5–10.4. The predominant adsorbed arsenate species were modeled as bidentate binuclear surface complexes at low pH and as monodentate complexes at high pH. The immobilized arsenic remained stable when aging for 270 d at room temperature. PMID:28098196

  13. 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.

  14. 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

  15. 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.

  16. Enhanced removal of As (V) from aqueous solution using modified hydrous ferric oxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Huo, Lijuan; Zeng, Xibai; Su, Shiming; Bai, Lingyu; Wang, Yanan

    2017-01-01

    Hydrous ferric oxide (HFO) is most effective with high treatment capacity on arsenate [As(V)] sorption although its transformation and aggregation nature need further improvement. Here, HFO nanoparticles with carboxymethyl cellulose (CMC) or starch as modifier was synthesized for the purpose of stability improvement and As(V) removal from water. Comparatively, CMC might be the optimum stabilizer for HFO nanoparticles because of more effective physical and chemical stability. The large-pore structure, high surface specific area, and the non-aggregated nature of CMC-HFO lead to increased adsorption sites, and thus high adsorption capacities of As(V) without pre-treatment (355 mg·g‑1), which is much greater than those reported in previous studies. Second-order equation and dual-mode isotherm model could be successfully used to interpret the sorption kinetics and isotherms of As(V), respectively. FTIR, XPS and XRD analyses suggested that precipitation and surface complexation were primary mechanisms for As(V) removal by CMC modified HFO nanoparticles. A surface complexation model (SCM) was used to simulate As adsorption over pH 2.5–10.4. The predominant adsorbed arsenate species were modeled as bidentate binuclear surface complexes at low pH and as monodentate complexes at high pH. The immobilized arsenic remained stable when aging for 270 d at room temperature.

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

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

    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.

  18. 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.

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

    PubMed

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

    2015-03-02

    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.

  20. Preferable uptake of phosphate by hydrous zirconium oxide nanoparticles embedded in quaternary-ammonium Chinese reed.

    PubMed

    Shang, Yanan; Xu, Xing; Qi, Shuto; Zhao, Yanxia; Ren, Zhongfei; Gao, Baoyu

    2017-02-12

    Phosphate capture from aqueous was conducted using hydrous zirconium oxide (HZO) embedded in quaternary-ammonium Chinese reed (CR-N(+)-HZO), and the characteristics of adsorbent was determined. HZO was dispersed as nanoparticles or nano-clusters on the external or inside the networking pores of CR-N(+)-HZO. The surface of CR-N(+)-HZO was heterogeneous with multiple adsorption sites, HZO nanocomposite and N(+)(CH2CH3)3Cl(-), which both contributed to the adsorption process. The phosphate uptake by CR-N(+)-HZO was optimal at pH 3.0 and phosphate uptake by HZO nanocomposite was greatly inhibited at alkaline pH. Kinetics studies suggested that both the intra-particle mass-transfer and external resistances were likely to be the rate controlling steps. The Qmax (maximum adsorption capacity) of phosphate uptake by CR-N(+)-HZO and CR-N(+) (30°C) calculated based on Langmuir model was about 59.2mg(P)/g(CR-N(+)-HZO) and 30.4mg(P)/g(CR-N(+)). A high usage efficiency of Zr in CR-N(+)-HZO was observed with calculated molar ratio of P/Zr to be 3.07.

  1. Sulfur in Hydrous, Oxidized Basaltic Magmas: Phase Equilibria and Melt Solubilities

    NASA Astrophysics Data System (ADS)

    Pichavant, M.; Scaillet, B.; di Carlo, I.; Rotolo, S.; Metrich, N.

    2006-05-01

    Basaltic magmas from subduction zone settings are typically S-rich and may be the ultimate source of sulfur in vapor phases emitted during eruptions of more silicic systems. To understand processes of sulfur recycling in subduction zones, the behaviour of S in hydrous, oxidized, mafic arc magmas must be known. Although experimental data on S-bearing basaltic melts are available for dry conditions, and under both reduced and oxidized fO2, no study has yet examined the effect of S in hydrous mafic melts. In this work, 3 starting compositions were investigated, a basaltic andesite, a K basalt and a picritic basalt. For each composition, experimental data for S-added (1 wt % elemental sulfur) and S-free charges were obtained under similar P-T- H2O-fO2. All experiments were performed at 4 kbar and at either 950 ° C (basaltic andesite), 1100 ° C (K basalt) or 1150 ° C (picritic basalt). These were carried out in an internally heated vessel pressurized with Ar-H2 mixtures and fitted with a drop-quench device, and lasted for between 15 and 99 h. Either Au (950 ° C) or AuPd alloys (1100 and 1150 ° C) were used as containers. These latter perform satisfactorily under strongly oxidizing conditions, i.e., for fO2 above NNO+1 at 1100 and 1150 ° C. Below NNO+1, Pd- Au-S-Fe phases appear in the charges, suggesting extensive interaction between S and the capsule material. Experimental redox conditions, determined from Ni-Pd-O sensors, ranged between NNO+1.3 to +4.1 (basaltic andesite), +0.6 to +2.0 (K basalt), and +0.3 to +3.6 (picritic basalt). H2O concentrations in melt ranged from 8.2 wt % (basaltic andesite), decreasing to 2.2-3.9 wt % (K basalt) and 2.5-5.0 wt % (picritic basalt). All 3 compositions studied crystallize anhydrite and Fe-Ni-S-O sulphide as saturating S-bearing phases, anhydrite at high fO2 and sulphide at lower fO2, although melt composition also influences their stability. Anhydrite is present at a fO2 as low as NNO+1.5 in the K basalt. In the picritic

  2. Crystallization of oxidized, moderately hydrous arc basalt at mid-to-lower crustal pressures

    NASA Astrophysics Data System (ADS)

    Blatter, D. L.; Sisson, T. W.; Hankins, W. B.

    2012-12-01

    Decades of experimental work show that dry, reduced, subalkaline basalts differentiate to produce tholeiitic (high Fe/Mg) daughter liquids, however the influences of H2O and oxidation on differentiation paths are not well established. Accordingly, we performed crystallization experiments on a relatively magnesian basalt (8.7 wt% MgO) typical of mafic lavas erupted in the Cascades magmatic arc near Mount Rainier, Washington. Starting material was synthesized with 3 wt% H2O and run in 2.54 cm piston-cylinder vessels at 900, 700, and 400 MPa and 1200 to 925 degrees C. Samples were contained in Au75Pd25 capsules pre-saturated with Fe by reaction with magnetite at controlled fO2. Oxygen fugacity was controlled during high-pressure syntheses by the double capsule method using Re-ReO2 plus H2O-CO2 vapor in the outer capsule, mixed to match the expected fH2O of the vapor-undersaturated sample. Crystallization was similar at all pressures with a high temperature interval consisting of augite + olivine + orthopyroxene + Cr-spinel (in decreasing abundance). With decreasing temperature, plagioclase crystallizes, FeTi-oxides replace spinel, olivine dissolves, and finally amphibole appears. Liquids at 900 MPa track along Miyashiro's (1974) tholeiitic vs. calc-alkaline boundary, whereas those at 700 and 400 MPa become calc-alkaline by ~57 wt% SiO2 and greater. Although these evolved liquids are similar in most respects to common calc-alkaline andesites, they differ in having low-CaO due to early and abundant crystallization of augite prior to plagioclase, with the result that they become peraluminous (ASI: Al/(Na+K+Ca)>1) by ~55 wt% SiO2, similar to liquids reported in other studies of the high-pressure crystallization of hydrous basalts (Müntener and Ulmer, 2006 and references therein). A compilation of >7000 analyses of volcanic and intrusive rocks from the Cascades and the Sierra Nevada batholith shows that ASI in arc magmas increases continuously and linearly with SiO2 from

  3. 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.

  4. The Fouling of Zirconium(IV) Hydrous Oxide-Polyacrylate Dynamically Formed Membranes during the Nanofiltration of Lactic Acid Solutions.

    PubMed

    Polom, Ewa

    2013-12-10

    The results of investigations of flux decline during nanofiltration (NF) of lactic acid solutions using dynamically formed zirconium(IV) hydrous oxide/polyacrylate membranes (Zr(IV)/PAA) under conditions resulting in low and high lactic acid rejection are reported. The experimental permeate flux versus time curves were analyzed in the frame of resistance in a series model with the aim of developing the characteristic of resistances. Analysis of experimental data and results of calculations showed that the reduction of fouling effects in the investigated system could be achieved due to appropriate hydrodynamic process conditions and regular rinsing with deionized water.

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

    USGS Publications Warehouse

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

    1984-01-01

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

  6. 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.

  7. 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.

  8. Hydrous manganese oxide doped gel probe sampler for measuring in situ reductive dissolution rates. 1. Laboratory development.

    PubMed

    Farnsworth, Claire E; Hering, Janet G

    2010-01-01

    Reductive dissolution of redox-sensitive minerals such as manganese (Mn) oxides in natural sediments is an important mechanism for trace element mobilization into groundwater. A gel probe sampler has been constructed to study in situ reductive dissolution of Mn oxides. The gel consists of a polyacrylamide polymer matrix doped with hydrous Mn oxide (HMO). Gel slabs are mounted into a probe, which is designed to be inserted into the sediments. The amount of Mn released from the gel by reductive dissolution is determined by comparing the amount of Mn initially embedded into the gel with the amount remaining in the gel after exposure to conditions in the sediments or, in laboratory studies, to reducing agents. In this laboratory study, the performance of the gel probes was examined using the model reductant ascorbate and the Mn-reducing bacteria Shewanella oneidensis strain MR-1. In addition, a 1-D model was used to relate the reaction rates observed for HMO embedded in gels to those for HMO in suspension. One limitation of the HMO-doped gels for assessing microbial reduction rates is that the gels prevent direct contact between the microbes and the HMO and hence preclude enzymatic reduction at the cell surface. Nonetheless, the HMO-doped gel probes offer the possibility to establish a lower bound for Mn-reduction capacity in sediments.

  9. A model-based evaluation of sorptive reactivities of hydrous ferric oxide and hematite for U(VI).

    PubMed

    Jang, Je-Hun; Dempsey, Brian A; Burgos, William D

    2007-06-15

    The sorption of uranyl onto hydrous ferric oxide (HFO) or hematite was measured by discontinuously titrating the suspensions with uranyl at pH 5.9, 6.8, and 7.8 under Pco2 = 10(-35)atm (sorption isotherms). Batch reactors were used with equilibration times up to 48 days. Sorption of 1 microM uranyl onto HFO was also measured versus pH (sorption edge). A diffuse double layer surface complexation model was calibrated by invoking three sorption species that were consistent with spectroscopic evidence for predominance of bidentate complexes at neutral pH and uranyl-carbonato complexes: > SOH:UO2OH(+1), (> SO)2: UO2CO3(-2), and (> SO)2:(UO2)3(OH)5(-1). The model was consistent with previously published isotherm and edge data. The model successfully predicted sorption data onto hematite, only adjusting for different measured specific surface area. Success in application of the model to hematite indicates that the hydrated surface of hematite has similar sorptive reactivity as HFO.

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

    PubMed

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

    2016-01-01

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

  11. Predicting divalent metal sorption to hydrous Al, Fe, and Mn oxides.

    PubMed

    Trivedi, P; Axe, L

    2001-05-01

    Intraparticle diffusion in microporous amorphous oxides of aluminum, iron, and manganese affects contaminant mobility and bioavailability in soils and sediments. This sorption is a lengthy process, as such, predictive methods to assess thermodynamic and transport parameters would be useful. Based on enthalpies observed in recent work, adsorption of Zn, Cd, and Sr to amorphous oxides is a physical type of reaction where the metal ions retain their waters of hydration. Consequently the adsorbate-surface interactions are a function of electrostatic forces of attraction. Accordingly, knowing the hydrated radius and the hydration number of a metal cation, a correlation is used to predict enthalpy and hence affinity. Using the resulting enthalpy and the Polanyi relation, the activation energy was evaluated for Ni and Ca. This Polanyi relationship reveals that for a given metal the activation energies with respect to these oxides are comparable. Additionally, metals of the same periodic group appear to form similar sorption complexes with a particular oxide and therefore have an equivalent Polanyi constant, alpha. Assuming a sinusoidal function describes the surface potential along the oxide surface, the surface diffusivity was predicted from the site activation theory. In this work, the predicted sorption parameters proved to be equivalent to experimental ones given the associated errors.

  12. 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

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

    PubMed Central

    Mao, Yanpeng; Yue, Qinyan

    2016-01-01

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

  14. Similarity of the Surface Reactivity of Hydrous Ferric Oxide and Hematite: Sorption and Redox of U(VI) and Fe(II)

    SciTech Connect

    Je-Hun Jang; Dempsey, Brian A.; Burgos, William D.; Yeh, George; Roden, Eric

    2004-03-17

    Hydrous Ferric Oxide (HFO) vs. Hematite--Thermodynamically distinctive bulk phases, but the surfaces could be similar due to hydration of the interface. Hypothesis--The surface of HFO is energetically similar to the surface of hematite. Objective--Compare the reactions of HFO and hematite with U(VI) and Fe(II). Experimental--The reactions of interests were (1) preparation of sub-micron hematite, (2) sorption of U(VI), and (3) redox of U(VI) and Fe(II) with HFO or hematite.

  15. Oxidation Chemistry of Inorganic Benzene Complexes.

    PubMed

    Fleischmann, Martin; Dielmann, Fabian; Balázs, Gábor; Scheer, Manfred

    2016-10-17

    The oxidation of the 28 VE cyclo-E6 triple-decker complexes [(Cp(R) Mo)2 (μ,η(6) :η(6) -E6 )] (E=P, Cp(R) =Cp(2 a), Cp*(2 b), Cp(Bn) (2 c)=C5 (CH2 Ph)5 ; E=As, Cp(R) =Cp*(3)) by Cu(+) or Ag(+) leads to cationic 27 VE complexes that retain their general triple-decker geometry in the solid state. The obtained products have been characterized by cyclic voltammetry (CV), EPR, Evans NMR, multinuclear NMR spectroscopy, MS, and structural analysis by single-crystal X-ray diffraction. The cyclo-E6 middle decks of the oxidized complexes are distorted to a quinoid (2 a) or bisallylic (2 b, 2 c, 3) geometry. DFT calculations of 2 a, 2 b, and 3 persistently result in the bisallylic distortion as the minimum geometry and show that the oxidation leads to a depopulation of the σ-system of the cyclo-E6 ligands in 2 a-3. Among the starting complexes, 2 c is reported for the first time including its preparation and full characterization.

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

    NASA Astrophysics Data System (ADS)

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

    2013-09-01

    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 (M

  17. 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

  18. 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

  19. Sulfur speciation in hydrous experimental glasses of varying oxidation state - Results from measured wavelength shifts of sulfur X-rays

    NASA Technical Reports Server (NTRS)

    Carroll, Michael R.; Rutherford, Malcolm J.

    1988-01-01

    The focusing geometry of an electron microprobe has been used to measure the wavelength shifts of sulfur X-rays from hydrous experimental melts synthesized at oxygen fugacities that range from near the iron-wustite buffer to the magnetite-hermatite buffer. It is found that the proportion of dissolved sulfur which is present as sulfate increases with increasing oxygen fugacity. It is noted that in natural melts that have equilibrated at or below fayalite-magnetite-quartz values of +1, sulfur is probably present mainly as S(2-).

  20. The influence of hydrous Mn–Zn oxides on diel cycling of Zn in an alkaline stream draining abandoned mine lands

    USGS Publications Warehouse

    Shope, Christopher L.; Xie, Ying; Gammons, Christopher H.

    2006-01-01

    Many mining-impacted streams in western Montana with pH near or above neutrality display large (up to 500%) diel cycles in dissolved Zn concentrations. The streams in question typically contain boulders coated with a thin biofilm, as well as black mineral crusts composed of hydrous Mn–Zn oxides. Laboratory mesocosm experiments simulating diel behavior in High Ore Creek (one of the Montana streams with particularly high Zn concentrations) show that the Zn cycles are not caused by 24-h changes in streamflow or hyporheic exchange, but rather to reversible in-stream processes that are driven by the solar cycle and its attendant influence on pH and water temperature (T). Laboratory experiments using natural Mn–Zn precipitates from the creek show that the mobilities of Zn and Mn increase nearly an order of magnitude for each unit decrease in pH, and decrease 2.4-fold for an increase in T from 5 to 20 °C. The response of dissolved metal concentration to small changes in either pH or T was rapid and reversible, and dissolved Zn concentrations were roughly an order of magnitude higher than Mn. These observations are best explained by sorption of Zn2+ and Mn2+ onto the secondary Mn–Zn oxide surfaces. From the T-dependence of residual metal concentrations in solution, approximate adsorption enthalpies of +50 kJ/mol (Zn) and +46 kJ/mol (Mn) were obtained, which are within the range of enthalpy values reported in the literature for sorption of divalent metal cations onto hydrous metal oxides. Using the derived pH- and T-dependencies from the experiments, good agreement is shown between predicted and observed diel Zn cycles for several historical data sets collected from High Ore Creek.

  1. Inorganic sulfur oxidizing system in green sulfur bacteria.

    PubMed

    Sakurai, Hidehiro; Ogawa, Takuro; Shiga, Michiko; Inoue, Kazuhito

    2010-06-01

    Green sulfur bacteria use various reduced sulfur compounds such as sulfide, elemental sulfur, and thiosulfate as electron donors for photoautotrophic growth. This article briefly summarizes what is known about the inorganic sulfur oxidizing systems of these bacteria with emphasis on the biochemical aspects. Enzymes that oxidize sulfide in green sulfur bacteria are membrane-bound sulfide-quinone oxidoreductase, periplasmic (sometimes membrane-bound) flavocytochrome c sulfide dehydrogenase, and monomeric flavocytochrome c (SoxF). Some green sulfur bacteria oxidize thiosulfate by the multienzyme system called either the TOMES (thiosulfate oxidizing multi-enzyme system) or Sox (sulfur oxidizing system) composed of the three periplasmic proteins: SoxB, SoxYZ, and SoxAXK with a soluble small molecule cytochrome c as the electron acceptor. The oxidation of sulfide and thiosulfate by these enzymes in vitro is assumed to yield two electrons and result in the transfer of a sulfur atom to persulfides, which are subsequently transformed to elemental sulfur. The elemental sulfur is temporarily stored in the form of globules attached to the extracellular surface of the outer membranes. The oxidation pathway of elemental sulfur to sulfate is currently unclear, although the participation of several proteins including those of the dissimilatory sulfite reductase system etc. is suggested from comparative genomic analyses.

  2. 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

  3. Reduction of U(VI) by Fe(II) in the presence of hydrous ferric oxide and hematite: effects of solid transformation, surface coverage, and humic acid.

    PubMed

    Jang, Je-Hun; Dempsey, Brian A; Burgos, William D

    2008-04-01

    Fe(II) was added to U(VI)-spiked suspensions of hydrous ferric oxide (HFO) or hematite to compare the redox behaviors of uranium in the presence of two different Fe(III) (oxyhydr)oxides. Experiments were conducted with low or high initial sorption density of U(VI) and in the presence or absence of humic acid (HA). About 80% of U(VI) was reduced within 3 days for low sorbed U(VI) conditions, with either hematite or HFO. The {Fe(3+)} in the low U(VI) experiments at 3 days, based on measured Fe(II) and U(VI) and the assumed presence of amorphous UO(2(s)), was consistent with control by HFO for either initial Fe(III) (oxyhydr)oxide. After about 1 day, partial re-oxidation to U(VI) was observed in the low sorbed U(VI) experiments in the absence of HA, without equivalent increase of dissolved U(VI). No reduction of U(VI) was observed in the high sorbed U(VI) experiments; it was hypothesized that the reduction required sorption proximity of U(VI) and Fe(II). Addition of 5mg/L HA slowed the reduction with HFO and had less effect with hematite. Mössbauer spectroscopy (MBS) of (57)Fe(II)-enriched samples identified the formation of goethite, hematite, and non-stoichiometric magnetite from HFO, and the formation of HFO, hydrated hematite, and non-stoichiometric magnetite from hematite.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. [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.

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

    USGS Publications Warehouse

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

    2017-01-01

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

  11. 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).

  12. 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

  13. Probing the interactions between lignin and inorganic oxides using atomic force microscopy

    NASA Astrophysics Data System (ADS)

    Wang, Jingyu; Qian, Yong; Deng, Yonghong; Liu, Di; Li, Hao; Qiu, Xueqing

    2016-12-01

    Understanding the interactions between lignin and inorganic oxides has both fundamental and practical importance in industrial and energy fields. In this work, the specific interactions between alkali lignin (AL) and three inorganic oxide substrates in aqueous environment are quantitatively measured using atomic force microscopy (AFM). The results show that the average adhesion force between AL and metal oxide such as Al2O3 or MgO is nearly two times bigger than that between AL and nonmetal oxide such as SiO2 due to the electrostatic difference and cation-π interaction. When 83% hydroxyl groups of AL is blocked by acetylation, the adhesion forces between AL and Al2O3, MgO and SiO2 decrease 43, 35 and 75% respectively, which indicate hydrogen bonds play an important role between AL and inorganic oxides, especially in AL-silica system.

  14. 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.

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

    PubMed

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

    2011-12-01

    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.

  16. 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.

  17. 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

  18. Hydrous RuO2 nanoparticles as highly active electrocatalysts for hydrogen evolution reaction

    NASA Astrophysics Data System (ADS)

    Lee, Jooyoung; Sher Shah, Selim Arif; Yoo, Pil J.; Lim, Byungkwon

    2017-04-01

    This letter describes an aqueous-phase synthetic route to hydrous ruthenium oxide (RuO2) nanoparticles and their conversion into crystalline ones via a thermal annealing process. Electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy were employed to characterize hydrous and crystalline RuO2 nanoparticles. The hydrous RuO2 nanoparticles exhibited higher activity for hydrogen evolution reaction than commercial Pt catalyst, while the crystalline RuO2 nanoparticles showed better performance for oxygen evolution reaction than IrO2 catalyst. With these hydrous and crystalline RuO2 catalysts, we were able to achieve highly efficient overall electrochemical water splitting.

  19. 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

  20. 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.

  1. 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.

  2. Interactions of inorganic oxide nanoparticles with sewage biosolids.

    PubMed

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

    2012-01-01

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

  3. Relationship between hydrous and ordinary pyrolysis

    SciTech Connect

    Burnham, A.K.

    1993-06-01

    Pyrolysis results are reviewed briefly with the intent of drawing comparisons between open, high pressure, and hydrous pyrolysis. Empirically, the degree of pyrolysis severity to form volatile products in open pyrolysis is similar to that required to form an expelled oil phase in hydrous pyrolysis. The yields of hydrocarbons from open pyrolysis are close to those from hydrous pyrolysis, but hydrous pyrolysis tends to assist the separation of hydrocarbons from polar materials. Pressure has a small but measurable affect on the generation kinetics.

  4. 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.

  5. 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.

  6. Nanoscale growth and patterning of inorganic oxides using DNA nanostructure templates.

    PubMed

    Surwade, Sumedh P; Zhou, Feng; Wei, Bryan; Sun, Wei; Powell, Anna; O'Donnell, Christina; Yin, Peng; Liu, Haitao

    2013-05-08

    We describe a method to form custom-shaped inorganic oxide nanostructures by using DNA nanostructure templates. We show that a DNA nanostructure can modulate the rate of chemical vapor deposition of SiO2 and TiO2 with nanometer-scale spatial resolution. The resulting oxide nanostructure inherits its shape from the DNA template. This method generates both positive-tone and negative-tone patterns on a wide range of substrates and is compatible with conventional silicon nanofabrication processes. Our result opens the door to the use of DNA nanostructures as general-purpose templates for high-resolution nanofabrication.

  7. Investigation of oxidation and migration processes of inorganic compounds in ink-corroded manuscripts

    NASA Astrophysics Data System (ADS)

    Kanngießer, Birgit; Hahn, Oliver; Wilke, Max; Nekat, Bettina; Malzer, Wolfgang; Erko, Alexei

    2004-10-01

    We studied the oxidation and migration processes of inorganic compounds in iron gall inks with a combination of micro X-ray fluorescence analysis (micro-XRF) and micro X-ray absorption near edge structure spectroscopy (micro-XANES). With elemental mapping by micro-XRF, the correlation of the minor elements in the ink to the major element Fe was investigated. Along concentration profiles of Fe, micro-XANES measurements were carried out in order to determine the oxidation state and the local environment. With the help of model inks, we could show that Cu is a further important element in the paper degradation process due to iron gall ink corrosion.

  8. 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.

  9. Coating of uniform inorganic particles with polymers, I

    SciTech Connect

    Oyama, H.T.; Sprycha, R.; Xie, Yuming; Partch, R.E.; Matijevic, E. . Center for Advanced Materials Processing)

    1993-10-15

    Uniform spherical silica particles have been first coated with aluminum hydrous oxide and then with poly(divinylbenzene). To produce the outer shell, the inorganic cores were pretreated with a vinyl coupling agent, then divinylbenzene, and an initiator in hot mineral spirits. The thickness of the alumina or polymer layers could be controlled by adjusting the experimental parameters. The same procedure was used to coat irregularly shaped commercial alumina particles. The charge of the so prepared particles was determined by potentiometric titrations, which showed that the polymer coating was permeable to the reactants. Thus, the titration curves were determined by the properties of the cores.

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

    PubMed

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

    2015-11-03

    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.

  11. 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.

  12. 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 +]…

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

    PubMed

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

    2012-02-21

    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 SnO(2) nanoparticles embedded in SiO(2) 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.

  14. 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.

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

    PubMed

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

    2015-03-03

    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.

  16. Effects of inorganics on the degradation of micropollutants with vacuum UV (VUV) advanced oxidation.

    PubMed

    Duca, Clara; Imoberdorf, Gustavo; Mohseni, Madjid

    2017-02-21

    This research focused on the effects of inorganic water constituents on the efficiency of vacuum UV (VUV) for the degradation of micropollutants in surface water supplies. Atrazine was used as a model miropollutant, and bicarbonate, sulphate, and nitrate were used as the most common inorganic constituents in the water matrix. First, the absorbance of radiation at 254 and 185 nm was measured in the presence of different ions. At 254 nm, only nitrate showed a measurable absorption coefficient of [Formula: see text] = 3.51 M[Formula: see text] cm[Formula: see text], and all other ions showed a molar absorption coefficient below the detection limit. However, at 185 nm, all the ions showed high absorption coefficients, with nitrate giving the highest absorption coefficient of [Formula: see text] = 5568 M[Formula: see text] cm[Formula: see text]. Second, the hydroxyl radical (HO[Formula: see text]) scavenging effects of the same inorganic ions were evaluated; nitrate and bicarbonate showed a negative effect during the UV/H2O2 and VUV advanced oxidation processes. Sulfate was photolyzed with 185 nm UV to form HO[Formula: see text], and for this reason, it assisted the degradation of the target micropollutant, as demonstrated by increases in the degradation rate constant. An additional component of this work involved developing a method for measuring the quantum yield of atrazine at 185 nm. This made it possible to distinguish the contribution of OH radical attach from that of direct photolysis towards the degradation of atrazine.

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

    NASA Astrophysics Data System (ADS)

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

    2016-07-01

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

  18. 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.

  19. Fabrication of a new hydrous Zr(IV) oxide-based nanocomposite for enhanced Pb(II) and Cd(II) removal from waters.

    PubMed

    Hua, Ming; Jiang, Yingnan; Wu, Bian; Pan, Bingcai; Zhao, Xin; Zhang, Quanxing

    2013-11-27

    To overcome the technical bottleneck of fine hydrated Zr(IV) oxide particles in environmental remediation, we irreversibly impregnated nanosized hydrated Zr(IV) oxide inside a commercial cation exchange resin D-001 and obtained a new nanocomposite NZP. NZP exhibited efficient removal of lead and cadmium ions in a pH range of 2-6, where no Zr(IV) leaching was detected from NZP. As compared to D-001, NZP showed more preferable adsorption toward both toxic metals from the background Ca(II) solution at greater levels. The synthetic Pb(II) or Cd(II) solution containing other ubiquitous metal ions was employed as the feeding influent for column adsorption, and the results indicated that the treatable volume of NZP is around 3-4 times that of D-001 before reaching the breakthrough point set according to the effluent discharge standard of China. With respect to Pb(II) removal from an acidic mining effluent, the treatable volume of NZP was 13 times higher than that of D-001. The exhausted NZP could be effectively regenerated by HNO3-Ca(NO3)2 binary solution for repeated use without any significant capacity loss. The superior performance of NZP was attributed to the Donnan membrane effect exerted by the host D-001 as well as the impregnated HZO nanoparticles of specific interaction toward toxic metals, as confirmed by the comparative isothermal adsorption and X-ray photoelectron spectroscopic study.

  20. An inorganic geochemical argument for coupled anaerobic oxidation of methane and iron reduction in marine sediments.

    PubMed

    Riedinger, N; Formolo, M J; Lyons, T W; Henkel, S; Beck, A; Kasten, S

    2014-03-01

    Here, we present results from sediments collected in the Argentine Basin, a non-steady state depositional marine system characterized by abundant oxidized iron within methane-rich layers due to sediment reworking followed by rapid deposition. Our comprehensive inorganic data set shows that iron reduction in these sulfate and sulfide-depleted sediments is best explained by a microbially mediated process-implicating anaerobic oxidation of methane coupled to iron reduction (Fe-AOM) as the most likely major mechanism. Although important in many modern marine environments, iron-driven AOM may not consume similar amounts of methane compared with sulfate-dependent AOM. Nevertheless, it may have broad impact on the deep biosphere and dominate both iron and methane cycling in sulfate-lean marine settings. Fe-AOM might have been particularly relevant in the Archean ocean, >2.5 billion years ago, known for its production and accumulation of iron oxides (in iron formations) in a biosphere likely replete with methane but low in sulfate. Methane at that time was a critical greenhouse gas capable of sustaining a habitable climate under relatively low solar luminosity, and relationships to iron cycling may have impacted if not dominated methane loss from the biosphere.

  1. A global model of tropospheric chlorine chemistry: Organic versus inorganic sources and impact on methane oxidation

    NASA Astrophysics Data System (ADS)

    Hossaini, Ryan; Chipperfield, Martyn P.; Saiz-Lopez, Alfonso; Fernandez, Rafael; Monks, Sarah; Feng, Wuhu; Brauer, Peter; Glasow, Roland

    2016-12-01

    Chlorine atoms (Cl) are highly reactive toward hydrocarbons in the Earth's troposphere, including the greenhouse gas methane (CH4). However, the regional and global CH4 sink from Cl is poorly quantified as tropospheric Cl concentrations ([Cl]) are uncertain by 2 orders of magnitude. Here we describe the addition of a detailed tropospheric chlorine scheme to the TOMCAT chemical transport model. The model includes several sources of tropospheric inorganic chlorine (Cly), including (i) the oxidation of chlorocarbons of natural (CH3Cl, CHBr2Cl, CH2BrCl, and CHBrCl2) and anthropogenic (CH2Cl2, CHCl3, C2Cl4, C2HCl3, and CH2ClCH2Cl) origin and (ii) sea-salt aerosol dechlorination. Simulations were performed to quantify tropospheric [Cl], with a focus on the marine boundary layer, and quantify the global significance of Cl atom CH4 oxidation. In agreement with observations, simulated surface levels of hydrogen chloride (HCl), the most abundant Cly reservoir, reach several parts per billion (ppb) over polluted coastal/continental regions, with sub-ppb levels typical in more remote regions. Modeled annual mean surface [Cl] exhibits large spatial variability with the largest levels, typically in the range of 1-5 × 104 atoms cm-3, in the polluted northern hemisphere. Chlorocarbon oxidation provides a tropospheric Cly source of up to 4320 Gg Cl/yr, sustaining a background surface [Cl] of <0.1 to 0.5 × 103 atoms cm-3 over large areas. Globally, we estimate a tropospheric methane sink of 12-13 Tg CH4/yr due the CH4 + Cl reaction ( 2.5% of total CH4 oxidation). Larger regional effects are predicted, with Cl accounting for 10 to >20% of total boundary layer CH4 oxidation in some locations.

  2. 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.

  3. Formation and reactivity of inorganic and organic chloramines and bromamines during oxidative water treatment.

    PubMed

    Heeb, Michèle B; Kristiana, Ina; Trogolo, Daniela; Arey, J Samuel; von Gunten, Urs

    2017-03-01

    The formation and further reactions of halamines during oxidative water treatment can be relevant for water quality. In this study, we investigated the formation and reactivity of several inorganic and organic halamines (monochloramine, N-chloromethylamine, N-chlorodimethylamine, monobromamine, dibromamine, N-bromomethylamine, N,N-dibromomethylamine, and N-bromodimethylamine) by kinetic experiments, transformation product analysis, and quantum chemical computations. Kinetic model simulations were conducted to evaluate the relevance of halamines for various water treatment scenarios. Halamines were quickly formed from the reaction of chlorine and bromine with ammonia or organic amines. Species-specific second-order rate constants for the reaction of chlorine and bromine with ammonia, methyl- and dimethylamine were in the order of 10(6)-10(8) M(-1)s(-1). The formed halamines were found to be reactive towards phenolic compounds, forming halogenated phenols via electrophilic aromatic substitution (phenol and resorcinol) or quinones via electron transfer (catechol and hydroquinone). At near neutral pH, apparent second-order rate constants for these reactions were in the order of 10(-4)-10(-1) M(-1)s(-1) for chloramines and 10(1)-10(2) M(-1)s(-1) for bromamines. Quantum chemical computations were used to determine previously unknown aqueous pKa values, gas phase bond dissociation energies (BDE) and partial atomic charges of the halamines, allowing a better understanding of their reactivities. Kinetic model simulations, based on the results of this study, showed that during chlorination inorganic and organic chloramines are the main halamines formed. However, their further reactions with organic matter are outcompeted kinetically by chlorine. During ozonation, mainly inorganic bromamines are formed, since ozone quickly oxidizes organic amines. The further reactions of bromamine are typically outcompeted by ozone and thus generally of minor importance. The use of

  4. 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.

  5. The patterning of sub-500 nm inorganic oxide and semiconducting polymeric structures

    NASA Astrophysics Data System (ADS)

    Hampton, Meredith J.; Williams, Stuart S.; Zhou, Zhilian; Nunes, Janine; Ko, Doo-Hyun; Templeton, Joseph L.; DeSimone, Joseph M.; Samulski, Edward T.

    2008-08-01

    The Pattern Replication In Non-wetting Templates (PRINT) technique has been extended to patterning of isolated features as well as embossed films of sub-500 nm "hard" inorganic oxides and nanocrystalline semiconductors and "soft" semiconducting polymers including TiO2, SnO2, ZnO, ITO, BaTiO3, CdSe, poly(3-hexylthiophene) (P3HT), Poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylenevinylene] (MDMO-PPV), and other polythiophene derivatives. The low surface energy, chemically resistant, air permeable elastomeric perflouropolyether (PFPE) based molds allow for numerous materials to be patterned on a variety of substrates including glass, transparent conductive oxides, and thin films of conducting polymer for a wide range of electronic and optical applications. Additionally, PRINT has been employed to pattern features with aspect ratios greater than 1, deposit a second layer of features on top of an initial layer without pattern destruction, and replicate sub-100 nm sized features for photovoltaics applications. Materials and patterns generated in this work were characterized using a variety of techniques including: Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and X-ray Diffraction (XRD).

  6. "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.

  7. An SOA model for toluene oxidation in the presence of inorganic aerosols.

    PubMed

    Cao, Gang; Jang, Myoseon

    2010-01-15

    A predictive model for secondary organic aerosol (SOA) formation including both partitioning and heterogeneous reactions is explored for the SOA produced from the oxidation of toluene in the presence of inorganic seed aerosols. The predictive SOA model comprises the explicit gas-phase chemistry of toluene, gas-particle partitioning, and heterogeneous chemistry. The resulting products from the explicit gas phase chemistry are lumped into several classes of chemical species based on their vapor pressure and reactivity for heterogeneous reactions. Both the gas-particle partitioning coefficient and the heterogeneous reaction rate constant of each lumped gas-phase product are theoretically determined using group contribution and molecular structure-reactivity. In the SOA model, the predictive SOA mass is decoupled into partitioning (OM(P)) and heterogeneous aerosol production (OM(H)). OM(P) is estimated from the SOA partitioning model developed by Schell et al. (J. Geophys. Res. 2001, 106, 28275-28293 ) that has been used in a regional air quality model (CMAQ 4.7). OM(H) is predicted from the heterogeneous SOA model developed by Jang et al. (Environ. Sci. Technol. 2006, 40, 3013-3022 ). The SOA model is evaluated using a number of the experimental SOA data that are generated in a 2 m(3) indoor Teflon film chamber under various experimental conditions (e.g., humidity, inorganic seed compositions, NO(x) concentrations). The SOA model reasonably predicts not only the gas-phase chemistry, such as the ozone formation, the conversion of NO to NO(2), and the toluene decay, but also the SOA production. The model predicted that the OM(H) fraction of the total toluene SOA mass increases as NO(x) concentrations decrease: 0.73-0.83 at low NO(x) levels and 0.17-0.47 at middle and high NO(x) levels for SOA experiments with high initial toluene concentrations. Our study also finds a significant increase in the OM(H) mass fraction in the SOA generated with low initial toluene

  8. Poly(ethylene oxide)-bonded stationary phase for separation of inorganic anions in capillary ion chromatography.

    PubMed

    Linda, Roza; Lim, Lee Wah; Takeuchi, Toyohide

    2013-06-14

    A tosylated-poly(ethylene oxide) (PEO) reagent was reacted with primary amino groups of an aminopropylsilica packing material (TSKgel NH2-60) in acetonitrile to form PEO-bonded stationary phase. The reaction was a single and simple step reaction. The prepared stationary phase was able to separate inorganic anions. The retention behavior of six common inorganic anions on the prepared stationary phase was examined under various eluent conditions in order to clarify its separation/retention mechanism. The elution order of the tested anions was iodate, bromate, bromide, nitrate, iodide, and thiocyanate, which was similar as observed in common ion chromatography. The retention of inorganic anions could be manipulated by ion exchange interaction which is expected that the eluent cation is coordinated among the PEO chains and it works as the anion-exchange site. Cations and anions of the eluent therefore affected the retention of sample anions. We demonstrated that the retention of the analyte anions decreased with increasing eluent concentration. The repeatability of retention time for the six anions was satisfactory on this column with relative standard deviation values from 1.1 to 4.3% when 10mM sodium chloride was used as the eluent. Compared with the unmodified TSKgel NH2-60, the prepared stationary phase retained inorganic anions more strongly and the selectivity was also improved. The present stationary phase was applied for the determination of inorganic anions contained in various water samples.

  9. Sulfide and sulfate saturation in hydrous silicate melts

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

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

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

    PubMed

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

    2011-06-01

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

  11. 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...

  12. 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.

  13. Evaluation of New Inorganic Sorbents for Strontium and Actinide Removal from High-Level Nuclear Waste Solutions

    SciTech Connect

    Hobbs, D.T.; Nyman, M.; Medvedev, D.G.; Tripathi, A.; Clearfield, A.

    2004-03-28

    Monosodium titanate (MST), a hydrous metal oxide sorbent, is the baseline material for the removal of 90Sr and alpha-emitting radionuclides (principally 238Pu, 239Pu, 240Pu and 237Np) from alkaline waste solutions generated during the processing of irradiated nuclear materials at the Savannah River Site. This material exhibits excellent performance characteristics for strontium removal. Plutonium removal is also good, but problematic at the estimated bonding concentration. We are currently developing new inorganic materials for improved sorption characteristics. These materials include sodium nonatitanates, pharmacosiderites and heteropolyniobates. We will present results evaluating the performance of these materials with simulated and actual high level nuclear waste solutions.

  14. Influence of 300°C thermal conversion of Fe-Ce hydrous oxides prepared by hydrothermal precipitation on the adsorptive performance of five anions: Insights from EXAFS/XANES, XRD and FTIR (companion paper).

    PubMed

    Chubar, Natalia; Gerda, Vasyl; Banerjee, Dipanjan

    2017-04-01

    In this work, we report atomic-scale reconstruction processes in Fe-Ce oxide-based composites (hydrothermally precipitated at Fe-to-Ce dosage ratios of 1:0, 2:1, 1:1, 1:2, and 0:1), upon treatment at 300°C. The structural changes are correlated with the adsorptive removal of arsenate, phosphate, fluoride, bromide, and bromate. The presence of the carbonate-based Ce-component and surface sulfate in precursor samples creates favorable conditions for phase transformation, resulting in the formation of novel (unknown) layered compounds of Fe and Ce. These compounds are of the layered double hydroxide type, with sulfate in the interlayer space. In spite of general awareness of the importance of surface area in adsorptive removal, the increase in surface area upon thermal treatment did not increase adsorption of the studied anions. However, EXAFS simulations and the adsorption tests provided evidence of regularities between local structures of Fe in composites obtained at 80 and 300°C and adsorption performance of most studied anions. The best adsorption of tetrahedral anions was demonstrated by samples whose simulated outer Fe shells resulted from oscillations from both O and Fe atoms. In contrast, the loss of extended x-ray absorption fine structure was correlated with the decrease of adsorptive removal. Both Fe K-edge and Ce L3 -edge EXAFS suggested the formation of solid solutions. For the first time, the utilization of extended x-ray absorption fine structure is suggested as a methodological approach (first expressed in the companion paper) to estimate the surface reactivity of inorganic materials intended for use as anion exchange adsorbents.

  15. Integrated Spectroscopic Studies of Hydrous Sulfate Minerals

    NASA Technical Reports Server (NTRS)

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

    2005-01-01

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

  16. Quantification of water in hydrous ringwoodite

    SciTech Connect

    Thomas, Sylvia -Monique; Jacobsen, Steven D.; Bina, Craig R.; Reichart, Patrick; Moser, Marcus; Hauri, Erik H.; Koch-Muller, Monika; Smyth, Joseph R.; Dollinger, Gunther

    2015-01-28

    Here, ringwoodite, γ-(Mg,Fe)2SiO4, in the lower 150 km of Earth’s mantle transition zone (410-660 km depth) can incorporate up to 1.5-2 wt% H2O as hydroxyl defects. We present a mineral-specific IR calibration for the absolute water content in hydrous ringwoodite by combining results from Raman spectroscopy, secondary ion mass spectrometery (SIMS) and proton-proton (pp)-scattering on a suite of synthetic Mg- and Fe-bearing hydrous ringwoodites. H2O concentrations in the crystals studied here range from 0.46 to 1.7 wt% H2O (absolute methods), with the maximum H2O in the same sample giving 2.5 wt% by SIMS calibration. Anchoring our spectroscopic results to absolute H-atom concentrations from pp-scattering measurements, we report frequency-dependent integrated IR-absorption coefficients for water in ringwoodite ranging from 78180 to 158880 L mol-1cm-2, depending upon frequency of the OH absorption. We further report a linear wavenumber IR calibration for H2O quantification in hydrous ringwoodite across the Mg2SiO4-Fe2SiO4 solid solution, which will lead to more accurate estimations of the water content in both laboratory-grown and naturally occurring ringwoodites. Re-evaluation of the IR spectrum for a natural hydrous ringwoodite inclusion in diamond from the study of the crystal contains 1.43 ± 0.27 wt% H2O, thus confirming near-maximum amounts of H2O for this sample from the transition zone.

  17. Quantification of water in hydrous ringwoodite

    DOE PAGES

    Thomas, Sylvia -Monique; Jacobsen, Steven D.; Bina, Craig R.; ...

    2015-01-28

    Here, ringwoodite, γ-(Mg,Fe)2SiO4, in the lower 150 km of Earth’s mantle transition zone (410-660 km depth) can incorporate up to 1.5-2 wt% H2O as hydroxyl defects. We present a mineral-specific IR calibration for the absolute water content in hydrous ringwoodite by combining results from Raman spectroscopy, secondary ion mass spectrometery (SIMS) and proton-proton (pp)-scattering on a suite of synthetic Mg- and Fe-bearing hydrous ringwoodites. H2O concentrations in the crystals studied here range from 0.46 to 1.7 wt% H2O (absolute methods), with the maximum H2O in the same sample giving 2.5 wt% by SIMS calibration. Anchoring our spectroscopic results to absolutemore » H-atom concentrations from pp-scattering measurements, we report frequency-dependent integrated IR-absorption coefficients for water in ringwoodite ranging from 78180 to 158880 L mol-1cm-2, depending upon frequency of the OH absorption. We further report a linear wavenumber IR calibration for H2O quantification in hydrous ringwoodite across the Mg2SiO4-Fe2SiO4 solid solution, which will lead to more accurate estimations of the water content in both laboratory-grown and naturally occurring ringwoodites. Re-evaluation of the IR spectrum for a natural hydrous ringwoodite inclusion in diamond from the study of the crystal contains 1.43 ± 0.27 wt% H2O, thus confirming near-maximum amounts of H2O for this sample from the transition zone.« less

  18. Fundamental Mvssbauer Parameters of Hydrous Iron Sulfates

    NASA Technical Reports Server (NTRS)

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

    2005-01-01

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

  19. 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

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

    PubMed

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

    2015-02-01

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

  1. 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

  2. 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.

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

    PubMed

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

    2003-12-15

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

  4. 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.

  5. Oxide-based inorganic/organic and nanoporous spherical particles: synthesis and functional properties

    PubMed Central

    Shiba, Kota; Tagaya, Motohiro; Tilley, Richard D; Hanagata, Nobutaka

    2013-01-01

    This paper reviews the recent progress in the preparation of oxide-based and heteroatom-doped particles. Surfactant-templated oxide particles, e.g. silica and titania, are possible candidates for various potential applications such as adsorbents, photocatalysts, and optoelectronic and biological materials. We highlight nanoporous oxides of one element, such as silicon or titanium, and those containing multiple elements, which exhibit properties that are not achieved with individual components. Although the multicomponent nanoporous oxides possess a number of attractive functions, the origin of their properties is hard to determine due to compositional/structural complexity. Particles with a well-defined size and shape are keys for a quantitative and detailed discussion on the unique complex properties of the particles. From this viewpoint, we review the synthesis techniques of the oxide particles, which are functionalized with organic molecules or doped with heteroatoms, the physicochemical properties of the particles and the possibilities for their photofunctional applications as complex systems. PMID:27877569

  6. 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.

  7. 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

  8. 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.

  9. Heat Capacity of Hydrous Silicate Melts

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  10. 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

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. 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.

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

    SciTech Connect

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

    2000-09-12

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

  17. Influence of Inorganic Nitrogen Management Regime on the Diversity of Nitrite-Oxidizing Bacteria in Agricultural Grassland Soils

    PubMed Central

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

    2005-01-01

    To assess links between the diversity of nitrite-oxidizing bacteria (NOB) in agricultural grassland soils and inorganic N fertilizer management, NOB communities in fertilized and unfertilized soils were characterized by analysis of clone libraries and denaturing gradient gel electrophoresis (DGGE) of 16S rRNA gene fragments. Previously uncharacterized Nitrospira-like sequences were isolated from both long-term-fertilized and unfertilized soils, but DGGE migration patterns indicated the presence of additional sequence types in the fertilized soils. Detailed phylogenetic analysis of Nitrospira-like sequences suggests the existence of one newly described evolutionary group and of subclusters within previously described sublineages, potentially representing different ecotypes; the new group may represent a lineage of noncharacterized Nitrospira species. Clone libraries of Nitrobacter-like sequences generated from soils under different long-term N management regimes were dominated by sequences with high similarity to the rhizoplane isolate Nitrobacter sp. strain PJN1. However, the diversity of Nitrobacter communities did not differ significantly between the two soil types. This is the first cultivation-independent study of nitrite-oxidizing bacteria in soil demonstrating that nitrogen management practices influence the diversity of this bacterial functional group. PMID:16332819

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

    PubMed

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

    2011-01-01

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

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

    PubMed

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

    2013-01-01

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

  20. 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

    2015-10-09

    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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. Aqueous process to limit hydration of thin-film inorganic oxides

    NASA Astrophysics Data System (ADS)

    Perkins, Cory K.; Mansergh, Ryan H.; Park, Deok-Hie; Nanayakkara, Charith E.; Ramos, Juan C.; Decker, Shawn R.; Huang, Yu; Chabal, Yves J.; Keszler, Douglas A.

    2016-11-01

    Aqueous-processed aluminum oxide phosphate (AlPO) dielectric films were studied to determine how water desorbs and absorbs on heating and cooling, respectively. In-situ Fourier transform infrared spectroscopy showed a distinct, reversible mono- to bidentate phosphate structural change associated with water loss and uptake. Temperature programmed desorption measurements on a 1-μm thick AlPO film revealed water sorption was inhibited by an aqueous-processed HfO2 capping film only 11-nm thick. The HfO2 capping film prevents water resorption, thereby preserving the exceptional performance of AlPO as a thin-film dielectric.

  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

    2015-01-13

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

  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. 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.

  9. 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.

  10. 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

  11. 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.

  12. 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

  13. Biosensor made with organic-inorganic hybrid composite: cellulose-tin oxide

    NASA Astrophysics Data System (ADS)

    Mahadeva, Suresha K.; Nayak, Jyoti; Kim, Jaehwan

    2011-04-01

    Cellulose is the most abundant polymer found in nature, inexhaustible, low cost, easy processing, renewable, biodegradable and biocompatible. SnO2, is a known electrical conductor that is optically transparent in the visible spectrum with a wide band gap at room temperature. Thus, a hybrid nanocomposite of cellulose and SnO2can offer a unique property of cellulose combined with electrical properties of SnO2. These unique properties of cellulose- SnO2 hybrid nanocomposite can be capitalized to design flexible, biodegradable and low cost biosensors. Preparation and characterization of cellulose-SnO2 hybrid nanocomposite and its application as a flexible urea biosensor was demonstrated in this paper. It is observed sensitivity of cellulose-SnO2 hybrid nanocomposite urea biosensor was increased linearly with deposition time. As deposition time increased, amount of tin oxide deposited over cellulose surface also increases, so as to increase the amount of enzyme immobilization and attachment of analyte, attributes to large current output and high sensitivity of sensor. Increasing enzyme activity is observed, with increasing urea concentration. Experimental results suggested that, the proposed biosensor under study is suitable for urea detection below 50 mM.

  14. Biosensor made with organic-inorganic hybrid composite: cellulose-tin oxide

    NASA Astrophysics Data System (ADS)

    K. Mahadeva, Suresha; Nayak, Jyoti; Kim, Jaehwan

    2011-03-01

    Cellulose is the most abundant polymer found in nature, inexhaustible, low cost, easy processing, renewable, biodegradable and biocompatible. SnO2, is a known electrical conductor that is optically transparent in the visible spectrum with a wide band gap at room temperature. Thus, a hybrid nanocomposite of cellulose and SnO2can offer a unique property of cellulose combined with electrical properties of SnO2. These unique properties of cellulose- SnO2 hybrid nanocomposite can be capitalized to design flexible, biodegradable and low cost biosensors. Preparation and characterization of cellulose-SnO2 hybrid nanocomposite and its application as a flexible urea biosensor was demonstrated in this paper. It is observed sensitivity of cellulose-SnO2 hybrid nanocomposite urea biosensor was increased linearly with deposition time. As deposition time increased, amount of tin oxide deposited over cellulose surface also increases, so as to increase the amount of enzyme immobilization and attachment of analyte, attributes to large current output and high sensitivity of sensor. Increasing enzyme activity is observed, with increasing urea concentration. Experimental results suggested that, the proposed biosensor under study is suitable for urea detection below 50 mM.

  15. Inorganic oxides with potential application in the preparation of a (68)Ge/(68)Ga generator system.

    PubMed

    Romero, E; Morcillo, M A

    2017-01-01

    The ion exchange properties of some tin and titanium oxides with potential application in the development of a (68)Ge/(68)Ga generator were determined. The best potential candidates, SnO2 and calcined SnO2, were further characterized by powder X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Brunauer-Emmett-Teller (BET) surface area analysis and its radiation stability was also determined. Two (68)Ge/(68)Ga pilot generators (1.85MBq) based on SnO2 and calcined SnO2 were developed and evaluated over 100 and 200 elution cycles respectively, using as eluent different concentrations of HCl. The generator based on calcined SnO2 showed higher (68)Ga elution yield and lower (68)Ge content in the eluate (75-80% and <3×10(-3)% respectively, 1-2M HCl) than the generator based on unheated SnO2 (60-65% and <1×10(-1)% respectively, 1-2M HCl). Nano-crystalline calcined SnO2 proved to be a promising sorbent; therefore it should be considered as an attractive candidate to develop (68)Ge/(68)Ga generators to produce gallium-68 for biomedical purposes.

  16. 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

  17. Hosts of hydrogen in ALH 84001: Evidence for hydrous martian salts in the oldest martian meteorite?

    NASA Astrophysics Data System (ADS)

    Eiler, John M.; Kitchen, Nami; Leshin, Lauri; Strausberg, Melissa

    2002-03-01

    The Martian meteorite, ALH84001, contains D-rich hydrogen of plausible Martian origin (Leshin et al. 1996). The phase identity of the host(s) of this hydrogen are not well known and could include organic matter (McKay et al., 1996), phlogopite (Brearley 2000), glass (Mittlefehldt 1994) and/or other, unidentified components of this rock. Previous ion microprobe studies indicate that much of the hydrogen in ALH84001 as texturally associated with concretions of nominally anhydrous carbonates, glass and oxides (Boctor et al., 1998; Sugiura and Hoshino, 2000). We examined the physical and chemical properties of the host(s) of this hydrogen by stepped pyrolysis of variously pre-treated sub-samples. A continuous-flow method of water reduction and mass spectrometry (Eiler and Kitchen 2001) was used to permit detailed study of the small amounts of this hydrogen-poor sample available for study. We find that the host(s) of D-rich hydrogen released from ALH84001 at relatively low temperatures (~500 deg C) is soluble in orthophosphoric and dilute hydrochloric acids and undergoes near-complete isotopic exchange with water within hours at temperatures of 200 to 300 deg C. These characteristics are most consistent with the carrier phase(s) being a hydrous salt (e.g., carbonate, sulfate or halide); the thermal stability of this material is inconsistent with many examples of such minerals (e.g., gypsum) and instead suggests one or more relatively refractory hydrous carbonates (e.g., hydromagnesite). Hydrous salts (particularly hydrous carbonates) are common on the earth only in evaporite, sabkha, and hydrocryogenic-weathering environments; we suggest that much (if not all) of the 'Martian' hydrogen in ALH84001 was introduced in analogous environments on or near the martian surface rather than through biological activity or hydrothermal alteration of silicates in the crust.

  18. 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

  19. 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.

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

    NASA Astrophysics Data System (ADS)

    Waters, L.; Lange, R. A.

    2011-12-01

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

  1. A note on the effects of inorganic seed aerosol on the oxidation state of secondary organic aerosol—α-Pinene ozonolysis

    NASA Astrophysics Data System (ADS)

    Huang, Dan Dan; Zhang, Xuan; Dalleska, Nathan F.; Lignell, Hanna; Coggon, Matthew M.; Chan, Chi-Ming; Flagan, Richard C.; Seinfeld, John H.; Chan, Chak K.

    2016-10-01

    We compare the oxidation state and molecular composition of α-pinene-derived secondary organic aerosol (SOA) by varying the types and surface areas of inorganic seed aerosol that are used to promote the condensation of SOA-forming vapors. The oxidation state of α-pinene SOA is found to increase with inorganic seed surface area, likely a result of enhanced condensation of low-volatility organic compounds on particles versus deposition on the chamber wall. α-Pinene SOA is more highly oxygenated in the presence of sodium nitrate (SN) seed than ammonium sulfate seed. The relative abundance of semivolatile monomers and low-volatility dimer components that account for more than half of α-pinene SOA mass is not significantly affected by the composition of seed aerosol. Enhanced uptake of highly oxidized small carboxylic acids onto SN seed particles is observed, which could potentially explain the observed higher SOA oxidation state in the presence of SN seed aerosol. Overall, our results demonstrate that a combined effect of seed aerosol composition and surface area leads to an increase in the O:C atomic ratio of α-pinene SOA by as much as a factor of 2.

  2. High Pressure Crystal Chemistry of Hydrous Ringwoodite

    NASA Astrophysics Data System (ADS)

    Holl, C. M.; Smyth, J. R.; Frost, D. J.; Jacobsen, S. D.

    2002-12-01

    Single crystals of hydrous Fo90 ringwoodite up to 800 μm in diameter have been synthesized in a multi-anvil press at 1400°C and 20 GPa. The crystals are deep blue in color and contain approximately 0.8 percent H2O by weight as measured by IR spectroscopy. The unit cell parameter of this material has been refined by single-crystal X-ray diffraction at 15 different pressures up to 3.8 GPa. Pressure was determined by refinement of the until cell volume of a standard quartz crystal. Preliminary values for the bulk modulus give a K0 = 172 +/- 9 GPa and K' = 5.1 +/- 1.6 over the range studied. The crystal structure of this material has been refined at six pressures up to 3.8 GPa. Refinements were obtained from an average of 13 unique data with values of Rf < 5%. Preliminary estimates of the polyhedral compressibilities are 1.0x10-2 GPa-1 (K = 100 GPa) for MgVI and 6.3x10-3 GPa-1 (K = 160 GPa) for SiIV. Comparison of the present data with previous results shows a systematic decrease in the bulk modulus of ringwoodite with H content. This decrease is larger than the effect of temperature within the allowable ranges of each so that an increase in H2O content of one percent would have an effect on the bulk modulus equivalent to raising the temperature by 500°C.

  3. Inorganic Halogen Oxidizer Research.

    DTIC Science & Technology

    1980-03-17

    J-1 RI/RD8O-134 V * Appendix K Self- Clinkering NF4 +Compositions f or NF3-F2 Gas Generators and Method of Producing Same...K-1 Appendix L Self- Clinkering Burning Rate Modifier for Solid Propellant NF 3-F 2Gas Generators for Chemical HF-DF Lasers...Self- Clinkering NF4 +Compositions for NF3-F2 * ~Gas Generators and M4ethod of Producing Same........ ......... 0-1 Appendix P Distribution List

  4. Inorganic Halogen Oxidizer Research

    DTIC Science & Technology

    1981-04-21

    methods devcloned in our laboratory for analyzing NF• salts. Experi mntal Caution: The hydrolysis of NF salts is highly exothermic and can be explo...1156. R1iRD8l-140 A-12 Table 1. The Determination of NF3 in Various NF: Salts by the Gas Chromatographic Method _- COMPOUND THEORETICAL EXPERIMENTAL ...found to be zero within experimental error. Those shifts of v3 and v, were computed as a function of of v,IF,) and P,(F,) were measured to be 29.25:r

  5. Inorganic Halogen Oxidizer Research.

    DTIC Science & Technology

    1982-04-21

    to the contract were: W. Sawodny, H. Haertner, K. Birk, and G. Fogarasi (University of Ulm, Germany), R. Bougon and T. Bui Huy (French Atomic Energy...chemical HF-DF laser, F atoms are generated by burning F2 in a precombustor with a fuel, such as hydrogen: F 2 + H - HF + F. .4 10 LM The F atoms are...solid F atom generator concept (Ref. 2), the F atoms were directly generated by burning the solid propellant grain, thus eliminating the need of a

  6. Inorganic Halogen Oxidizer Research

    DTIC Science & Technology

    1979-02-16

    Christe, Inorg. Chem., 11, 1220 (1972). 22. "Iodine Trisperchlorate and Cesium Tetraperchlorato Iodate (III)," by K. 0. Christe and C. J. Schack...Applied Chemistry, Proceedings of XXIV Internat. Congress, 4, •S (1974). 40. " Cesium Bis(perchlorato)bromat, (I), Cs+ [Br(OCl0 3) 2 ] ," by K. 0...RocKxITDYxN , A DiVISION OF NOaRTH AxzRICAN ROcKWRLL, CANOGA PARK, CALUPORNLA 913M0 Iodine Tris(perchlorate) and Cesium Tetrakis(perchlorato)iodate(III) By

  7. 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.

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

    NASA Astrophysics Data System (ADS)

    Mookherjee, M.; Mainprice, D.

    2014-12-01

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

  9. Crystallization Response of Hydrous Granitic Liquids

    NASA Astrophysics Data System (ADS)

    London, D.; Morgan, G. B.; Evensen, J. M.

    2006-05-01

    Preconditioning of hydrous haplogranite liquid (200 MPa eutectic composition Ab38Or28Qz34) at 100° C above the liquidus temperature for 72 hr is sufficient to eliminate any vestiges of the initial structural states of vitreous or crystalline starting materials. Experimental crystallization of this composition in the presence of aqueous vapor begins by nucleation in the vapor space, following which crystal growth advances into supercooled melt. The minimum in nucleation delay (~ 200 hrs) and maximum in nucleation density and growth rate occur at liquidus undercooling (ΔT) of 200° C. Crystallization does not exceed 10% in experiments up to 600 hrs at any value of ΔT, and no crystallization occurs within 50° C of the liquidus up to 700 hrs. Though the melt composition is invariant (eutectic), and no compositional gradients are discernable by EMPA in quenched glasses, the crystallization response is sequential: at ΔT = 200° C, coarsely skeletal K-feldspar nucleates and grows first, followed by graphic to spherulitic quartz-sodic alkali feldspar intergrowths, and lastly in some experiments, monophase quartz blebs. Once formed, crystals or clusters tend not to grow larger, but rather, new centers of nucleation and growth appear. The result is a sequential history of uniform crystal texture (size and habit). At comparable ΔT, the nucleation delay decreases as the bulk composition is displaced (by choosing a composition) farther from the eutectic. At comparable ΔT, fluxes (P, F) serve to increase the nucleation delay and decrease the nucleation density but do not notably change either growth rates or crystal habits. Diffusion of alkalis through melt is rapid, such that any gradients in alkalis that should result from non-eutectic crystallization are erased in minutes or hours over distances of 5 mm and down to ΔT = 350° C, in the field of glass. These relations of undercooling (ΔT) to time (t) apply only to H2O-oversaturated systems. We do not have data for the

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

    PubMed

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

    2015-09-01

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

  11. 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.

  12. 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…

  13. Steady-State Growth under Inorganic Carbon Limitation Conditions Increases Energy Consumption for Maintenance and Enhances Nitrous Oxide Production in Nitrosomonas europaea

    PubMed Central

    Giguere, Andrew; Chaplen, Frank; Bottomley, Peter J.

    2016-01-01

    ABSTRACT Nitrosomonas europaea is a chemolithoautotrophic bacterium that oxidizes ammonia (NH3) to obtain energy for growth on carbon dioxide (CO2) and can also produce nitrous oxide (N2O), a greenhouse gas. We interrogated the growth, physiological, and transcriptome responses of N. europaea to conditions of replete (>5.2 mM) and limited inorganic carbon (IC) provided by either 1.0 mM or 0.2 mM sodium carbonate (Na2CO3) supplemented with atmospheric CO2. IC-limited cultures oxidized 25 to 58% of available NH3 to nitrite, depending on the dilution rate and Na2CO3 concentration. IC limitation resulted in a 2.3-fold increase in cellular maintenance energy requirements compared to those for NH3-limited cultures. Rates of N2O production increased 2.5- and 6.3-fold under the two IC-limited conditions, increasing the percentage of oxidized NH3-N that was transformed to N2O-N from 0.5% (replete) up to 4.4% (0.2 mM Na2CO3). Transcriptome analysis showed differential expression (P ≤ 0.05) of 488 genes (20% of inventory) between replete and IC-limited conditions, but few differences were detected between the two IC-limiting treatments. IC-limited conditions resulted in a decreased expression of ammonium/ammonia transporter and ammonia monooxygenase subunits and increased the expression of genes involved in C1 metabolism, including the genes for RuBisCO (cbb gene cluster), carbonic anhydrase, folate-linked metabolism of C1 moieties, and putative C salvage due to oxygenase activity of RuBisCO. Increased expression of nitrite reductase (gene cluster NE0924 to NE0927) correlated with increased production of N2O. Together, these data suggest that N. europaea adapts physiologically during IC-limited steady-state growth, which leads to the uncoupling of NH3 oxidation from growth and increased N2O production. IMPORTANCE Nitrification, the aerobic oxidation of ammonia to nitrate via nitrite, is an important process in the global nitrogen cycle. This process is generally dependent

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

    PubMed

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

    2009-12-01

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

  15. The heat capacity of hydrous cordierite above 295 K

    NASA Astrophysics Data System (ADS)

    Carey, J. William

    1993-04-01

    The heat capacity of synthetic hydrous cordierite (Mg2Al4Si5O18·nH2O) has been determined by differential scanning calorimetry (DSC) from 295 to 425 K as a function of H2O content. Six samples with H2O contents ranging from 0 to 0.82 per formula unit were examined. The partial molar heat capacity of H2O in cordierite over the measured temperature interval is independent of composition and temperature within experimental uncertainty and is equal to 43.3 ±0.8 J/mol/ K. This value exceeds the molar heat capacity of gaseous H2O by 9.7 J/mol/K, but is significantly smaller than the heat capacity of H2O in several zeolites and liquid H2O. A statistical-mechanical model of the heat capacity of adsorbed gas species (Barrer 1978) is used to extrapolate the heat capacity of hydrous cordierite to temperatures greater than 425 K. In this model, the heat capacity of hydrous cordierite (Crd·nH2O) is represented as follows: Cp(Crd · nH2O) = Cp(Crd)+ n{Cp(H2O, gas)+ R(gas constant)} (1) An examination of calorimetric data for hydrous beryl, analcime, mordenite, and clinoptilolite (Hemingway et al. 1986; Johnson et al. 1982, 1991, 1992) demonstrates the general applicability of the statistical-mechanical model for the extrapolation of heat capacity data of zeolitic minerals. The heat capacity data for cordierite are combined with the data of Carey and Navrotsky (1992) to obtain the molar enthalpy of formation and enthalpy of hydration of hydrous cordierite as a function of temperature.

  16. 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

  17. 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

  18. 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.

  19. Microfluidics in inorganic chemistry.

    PubMed

    Abou-Hassan, Ali; Sandre, Olivier; Cabuil, Valérie

    2010-08-23

    The application of microfluidics in chemistry has gained significant importance in the recent years. Miniaturized chemistry platforms provide controlled fluid transport, rapid chemical reactions, and cost-saving advantages over conventional reactors. The advantages of microfluidics have been clearly established in the field of analytical and bioanalytical sciences and in the field of organic synthesis. It is less true in the field of inorganic chemistry and materials science; however in inorganic chemistry it has mostly been used for the separation and selective extraction of metal ions. Microfluidics has been used in materials science mainly for the improvement of nanoparticle synthesis, namely metal, metal oxide, and semiconductor nanoparticles. Microfluidic devices can also be used for the formulation of more advanced and sophisticated inorganic materials or hybrids.

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

    NASA Astrophysics Data System (ADS)

    Phillips, Cory Bernard

    1999-11-01

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

  1. Synthesis and characterizations of anion exchange organic-inorganic hybrid materials based on poly(2,6-dimethyl-1,4-phenylene oxide) (PPO)

    SciTech Connect

    Zhang Shaoling; Wu Cuiming; Xu Tongwen . E-mail: twxu@ustc.edu.cn; Gong Ming; Xu Xiaolong

    2005-07-15

    A series of poly(2,6-dimethyl-1,4-phenylene oxide) (PPO)-based organic-inorganic hybrid materials for anion exchange were prepared through sol-gel process of polymer precursors PPO-Si(OCH{sub 3}){sub 3}. PPO-Si(OCH{sub 3}){sub 3} were obtained from the reaction of bromomethylated PPO with 3-aminopropyl-trimethoxysilane (A1110). These polymer precursors then underwent hydrolysis and condensation with additional A1110 to generate hybrid materials. The reaction to produce polymer precursors was identified by FTIR; while FTIR, TGA, XRD, SEM, as well as conventional ion exchange capacity (IEC) measurements were conducted for the structures and properties of the prepared hybrids. TGA results show that this series of hybrid materials possess high thermal stability; XRD and SEM indicate that the prepared hybrid materials are amorphous and the inorganic and organic contents show good compatibility if the ratio between them is proper. The IEC values of the hybrid materials due to the amine groups range from 1.13 mmol/gBPPO (material i) to 4.80 mmol/gBPPO (material iv)

  2. 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.

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

    DOE PAGES

    Allen, H. M.; Draper, D. C.; Ayres, B. R.; ...

    2015-09-25

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

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. Structure and stability of hydrous minerals at high pressure

    NASA Astrophysics Data System (ADS)

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

    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.

  9. 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.

  10. 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.

  11. 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

  12. Assessment of the formation of inorganic oxidation by-products during the electrocatalytic treatment of ammonium from landfill leachates.

    PubMed

    Pérez, G; Saiz, J; Ibañez, R; Urtiaga, A M; Ortiz, I

    2012-05-15

    This work investigates the formation of oxidation by-products during the electrochemical removal of ammonium using BDD electrodes from wastewaters containing chlorides. The influence of the initial chloride concentration has been experimentally analyzed first, working with model solutions with variable ammonium concentration and second, with municipal landfill leachates. Two different levels of chloride concentration were studied, i) low chloride concentrations ranging between 0 and 2000 mg/L and, ii) high chloride concentrations ranging between 5000 and 20,000 mg/L. Ammonium removal took place mainly via indirect oxidation leading to the formation of nitrogen gas and nitrate as the main oxidation products; at high chloride concentration the formation of nitrogen gas and the rate of ammonium removal were both favored. However, chloride was also oxidized during the electrochemical treatment leading to the formation of free chlorine responsible of the ammonium oxidation, together with undesirable products such as chloramines, chlorate and perchlorate. Chloramines appeared during the treatment but they reached a maximum and then started decreasing, being totally removed when high chloride concentrations were used. With regard to the formation of chlorate and perchlorate once again the concentration of chloride exerted a strong influence on the formation kinetics of the oxidation by-products and whereas at low chloride concentrations, chlorate appeared like an intermediate compound leading to the formation of perchlorate, at high chloride concentrations chlorate formation was delayed significantly and perchlorate was not detected during the experimental time. Thus this work contributes first to the knowledge of the potential hazards of applying the electro-oxidation technology as an environmental technology to deal with ammonium oxidation under the presence of chloride and second it reports efficient conditions that minimize or even avoid the formation of undesirable

  13. 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

  14. In situ hydrothermal oxidative destruction of DNAPLS in a creosote contaminated site

    SciTech Connect

    Leif, R. N., LLNL

    1998-02-27

    Hydrous Pyrolysis / Oxidation (HPO) is an in situ thermal remediation technology that uses hot, oxygenated groundwater to completely mineralize a wide range of organic pollutants. A field demonstration of HPO was performed at a creosote contaminated site during the summer of 1997. The groundwater was heated by steam injections and oxygen was added by coinjection of compressed air. The remediation was monitored from multiple groundwater monitoring wells. Dissolved organic carbon levels increased in response to steam injections as a result of the enhanced dissolution and mobilization of the creosote into the heated groundwater. Elevated concentrations of partially oxidized organic compounds (i.e. phenols, benzoic acid, fluorenone, anthrone and 9,10- anthracenedione), decreased levels of dissolved oxygen and isotopic shifts in the dissolved inorganic pool were indicators of partial to complete oxidative destruction of the creosote in the heated aquifer as a result of the HPO process.

  15. [AFM study on microtopography of NOM and newly formed hydrous manganese dioxide adsorbed on mica].

    PubMed

    Guo, Jin; Ma, Jun; Shi, Xue-hua

    2006-05-01

    With the methods of mica adsorbing, the microtopography of the newly formed hydrous manganese dioxide was perfectly captured. The tapping mode AFM study results revealed that the newly formed hydrous manganese dioxide possesses a perforated sheet (with a thickness of 0-1.75 nm) as well as some spheric particle structures compared with the hydrous manganese dioxide with 2 h aging time, which demonstrated that the newly formed hydrous manganese dioxide have a large surface area and adsorption capacity. When 1 mmol/L newly formed hydrous manganese dioxide was added, the microtopography of NOM molecules shifted from loosely dispersed pancake shape (with adsorption height of 5-8.5 nm) to densely dispersed and uniform spheric structure. NOM was prone to adsorb on the surface of the newly formed hydrous manganese dioxide, which provided a valid proof for the coagulation-aid mechanism of permanganate preoxidation.

  16. Inorganic mercury exposure: toxicological effects, oxidative stress biomarkers and bioaccumulation in the tropical freshwater fish matrinxã, Brycon amazonicus (Spix and Agassiz, 1829).

    PubMed

    Monteiro, Diana Amaral; Rantin, Francisco Tadeu; Kalinin, Ana Lúcia

    2010-01-01

    Alterations in the antioxidant cellular system have often been proposed as biomarkers of pollutant-mediated toxicity. This study evaluated the effects of mercury on oxidative stress biomarkers and bioaccumulation in the liver, gills, white muscle and heart of the freshwater fish matrinxã, Brycon amazonicus, exposed to a nominal and sub-lethal concentration (~20% of 96 h-LC(50)) of 0.15 mg L(-1) of mercury chloride (HgCl(2)) for 96 h in a static system. Increases in superoxide dismutase, catalase, glutathione peroxidase (GPx), glutathione S-transferase (GST) and glutathione reductase (GR) were observed in all tissues after HgCl(2) exposure, except for white muscle GR activity and hepatic GPx. In the liver and gills, the exposure to HgCl(2) also induced significant increases in reduced glutathione (GSH). Conversely, exposure to HgCl(2) caused a significant decrease in the GSH levels and an increase in the oxidized glutathione (GSSG) content in the white muscle, while both GSH and GSSG levels increased significantly in the heart muscle. Metallothionein concentrations were significantly high after HgCl(2) exposure in the liver, gills and heart, but remained at control values in the white muscle. HgCl(2) exposure induced oxidative damage, increasing the lipid peroxidation and protein carbonyl content in all tissues. Mercury accumulated significantly in all the fish tissue. The pattern of accumulation follows the order gills > liver > heart > white muscle. In conclusion, these data suggest that oxidative stress in response to inorganic mercury exposure could be the main pathway of toxicity induced by this metal in fish.

  17. Effects of oxide electron transport layer on quantum dots light emitting diode with an organic/inorganic hybrid structure

    NASA Astrophysics Data System (ADS)

    Kim, Jiwan; Park, Yu Jin; Kim, Yohan; Kim, Yong-Hoon; Han, Chul Jong; Han, Jeong In; Oh, Min Suk

    2013-11-01

    We report on the effects of an oxide semiconductor as an electron transport layer (ETL) on a quantum dots light emitting diode (QD-LED). To improve the properties of QD-LED, we optimized the process parameters for the deposition and post-annealing steps of an oxide ETL. When zinc tin oxide (ZTO) was deposited by radio-frequency magnetron sputtering in a gas mixture of argon and oxygen (Ar : O2 = 2 : 1) and then annealed under 760 Torr O2 for 10 min, our QD-LED showed improved luminescence characteristics. Additionally, to overcome the problem of non-uniform luminescence, we optimized the concentration and process conditions of colloidal quantum dot materials. Finally, we fabricated QD-LED devices with luminescence of 4,874 cd/m2 and luminous efficiency of 2.68 cd/A.

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

    SciTech Connect

    Vasbinder, Michael John

    2006-01-01

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

  19. The Fouling of Zirconium(IV) Hydrous Oxide–Polyacrylate Dynamically Formed Membranes during the Nanofiltration of Lactic Acid Solutions

    PubMed Central

    Polom, Ewa

    2013-01-01

    The results of investigations of flux decline during nanofiltration (NF) of lactic acid solutions using dynamically formed zirconium(IV) hydrous oxide/polyacrylate membranes (Zr(IV)/PAA) under conditions resulting in low and high lactic acid rejection are reported. The experimental permeate flux versus time curves were analyzed in the frame of resistance in a series model with the aim of developing the characteristic of resistances. Analysis of experimental data and results of calculations showed that the reduction of fouling effects in the investigated system could be achieved due to appropriate hydrodynamic process conditions and regular rinsing with deionized water. PMID:24957066

  20. Effects of soil moisture, temperature, and inorganic nitrogen on nitric oxide emissions from acidic tropical savannah soils

    SciTech Connect

    Cardenas, L.; Sanhueza, E.; Rondon, A.; Johansson, C.

    1993-08-20

    NO fluxes from soils with a wide range of soil moistures, soil inorganic-N concentrations, and soil temperatures were measured during the wet and the dry season at a Venezuelan savannah site. Maximum NO emissions ({approximately} 12 ngN m{sup {minus}2} s{sup {minus}1}) were observed at soil gravimetric moistures between 10% and 18%. Deviation from this optimum range results in decreased NO fluxes; very low emissions (< 2 ngN m{sup {minus}2} s{sup {minus}1}) were recorded at low (< 2%) and high (< 25%) soil moistures. Both NO production in soil and its transport within the soil play important roles in the emission of NO to the atmosphere. Under most conditions no temperature effect was observed. NO emission was strongly stimulated by the addition of NO{sub 3}{sup {minus}} and only very weakly by the addition of NH{sub 4}{sup +}; at low and moderate soil moistures, soil nitrate and the NO flux were positively correlated. At low (natural) soil nitrate content and comparable soil moisture and temperature, NO emissions were greater during the dry season than during the rainy season, suggesting that other factors (i.e., soil physical structure) may also govern NO flux from savannah soil. 29 refs., 6 figs., 3 tabs.

  1. Respiration-dependent proton translocation in Nitrosomonas europaea and its apparent absence in Nitrobacter agilis during inorganic oxidations.

    PubMed Central

    Hollocher, T C; Kumar, S; Nicholas, D J

    1982-01-01

    Oxygen pulse experiments were carried out with the nitrifying bacteria Nitrosomonas europaea and Nitrobacter agilis and with spheroplasts and everted vesicles prepared from Nitrobacter agilis. In addition to thiocyanate, the salting-in anions perchlorate and trichloroacetate proved to be permeant and effective in allowing respiration-dependent proton translocation with Nitrosomonas europaea. Valinomycin-K+, however, was generally ineffective in this respect with Nitrosomonas europaea. The observed leads to H+/O ratio for ammonium ion oxidation by Nitrosomonas europaea was 3.4; that for hydroxylamine and hydrazine cation oxidation was 4.4. These values, when corrected for production of stoichiometric protons and for the fact that the first step in ammonium ion oxidation (hydroxylamine production) is mediated by a monooxygenase, give effective leads to H+/O ratios of about 4 for these three substrates. This value compares favorably with those obtained with other aerobes. No convincing evidence was obtained for operation of a respiratory proton pump in Nitrobacter agilis during nitrite oxidation. Implications of this unexpected result are discussed. PMID:6277846

  2. 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...

  3. 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.

  4. 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

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

    PubMed Central

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

    2016-01-01

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

  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.

  7. A Random Network Model of Electrical Conduction in Hydrous Rock

    NASA Astrophysics Data System (ADS)

    Fujita, K.; Seki, M.; Katsura, T.; Ichiki, M.

    2011-12-01

    To evaluate the variation in conductivity of hydrous rock during the dehydration, it is essential to comprehend the mechanism of electrical conduction network in rock. In the recent past, several attempts have been made to demonstrate the mechanism of electrical conduction network in hydrous rock. However, realistic conduction mechanism within the crustal rock and mineral is unknown and relevant theories have not been successful. The aim of our study is to quantify the electrical conduction network in the rock and/or mineral. We developed a cell-type lattice network model to evaluate the electrical conduction mechanism of fluid-mineral interaction. Using cell-type lattice model, we simulated the various electrical paths and connectivity in the rock and/or mineral sample. First, we assumed a network model consists of 100 by 100 elementary cells as matrix configuration. We also settled the current input and output layers at the edge of the lattice model. Second, we randomly generated and put the conductive and resistive cells using the scheme of Mersenne Twister. Third, we applied the current for this model and performed a great number of realization on each mineral distribution patterns explaining realistic conduction network model. Considering fractal dimensions, our model has been compared with images from Electron Probe Micro Analysis. To evaluate the distribution pattern of conductive and resistive cells quantitatively, we have determined fractal dimensions by box-counting method. Assessing the bulk conductivity change as a function of conductor ratio in the hydrous rock, the model has been examined successfully both against simulated data and experimental data.

  8. Inorganic Graphene Analogs

    NASA Astrophysics Data System (ADS)

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

    2015-07-01

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

  9. 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.

  10. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2016-09-01

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

  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. Effect of inorganic carbon concentration on the stability and nitrite-oxidizing bacteria community structure of the CANON process in a membrane bioreactor.

    PubMed

    Zhang, Xiaojing; Zhou, Yue; Ma, Yongpeng; Zhang, Nan; Zhao, Siyu; Zhang, Rongrong; Zhang, Jun; Zhang, Hongzhong

    2017-03-30

    In the completely autotrophic nitrogen removal over nitrite (CANON) process, the nitrite-oxidizing bacteria (NOB) should be effectively suppressed or thoroughly washed out. In this study, the nitrate production and the structure of NOB community under different inorganic carbon (IC) concentrations were investigated using denaturing gradient gel electrophoresis (DGGE) in a membrane bioreactor (MBR). Results showed that IC decrease correspondingly lowered the nitrogen removal, and simultaneously induced the nitrate production by NOB. DGGE results indicated the IC deficit led to the biodiversity increasing of both Nitrobacter-like NOB and Nitrospira-like NOB. An equation fitted between the ratio of nitrate production to ammonia consumption ([Formula: see text]) and the ratio of influent IC to ammonia concentration ([Formula: see text]) indicated the influent [Formula: see text] should be controlled between 1.6 and 2.3 to ensure the stable operation of the CANON process. A small amount addition of organic material could be used as an effective strategy to suppress NOB when the [Formula: see text] ratio was not appropriate.

  14. Utilization of titanium oxide-like compound as an inorganic phosphate adsorbent for the control of serum phosphate level in chronic renal failure.

    PubMed

    Tamagawa, Kazuhiko; Nakayama-Imaohji, Haruyuki; Wakimoto, Shin; Ichimura, Minoru; Kuwahara, Tomomi

    2010-08-01

    Hyperphosphatemia adversely affects the prognosis of patients with chronic renal failure (CRF). We synthesized a titanium oxide-like compound (TAP) as a phosphate adsorbent for treatment of hyperphosphatemia in CFR patients. We evaluated the ability of TAP to adsorb inorganic phosphate in vitro and in vivo. TAP was shown to contain sulfate and hydroxyl groups by thermal analysis, which probably involved in phosphate adsorption through an ionic exchange mechanism. TAP constantly adsorbed phosphate (66.20-72.84 mg/g TAP) over a wide pH range (1.22-7.27) in vitro. To evaluate the phosphate binding potential of TAP in vivo, adenine-induced CRF rats were fed AIN-76 diet containing 3% TAP, 10% TAP, 3% sevelamer hydrochloride (clinical phosphate adsorbent), or 3% calcium carbonate, and serum levels of phosphate and calcium and urinary phosphate were compared with those in untreated CRF rats. Orally administered TAP showed the inhibitory effect on serum phosphate level in adenine-induced CRF rats, which was equivalent to that of sevelamer hydrochloride. These results indicate that TAP is a useful alternative phosphate-binder with fewer side effects than sevelamer hydrochloride and calcium carbonate.

  15. Adsorption of natural dissolved organic matter at the oxide/water interface

    USGS Publications Warehouse

    Davis, James A.

    1982-01-01

    Natural organic matter is readily adsorbed by alumina and kaolinite in the pH range of natural waters. Adsorption occurs by complex formation between surface hydroxyls and the acidic functional groups of the organic matter. Oxides with relatively acidic surface hydroxyls, e.g. silica, do not react strongly with the organic matter. Under conditions typical for natural waters, almost complete surface coverage by adsorbed organic matter may be expected for alumina, hydrous iron oxides and the edge sites of aluminosilicates. Potentiometric titration and electrophoresis indicate that most of the acidic functional groups of the adsorbed organic matter are neutralized by protons from solution. The organic coating is expected to have a great influence on subsequent adsorption of inorganic cations and anions.

  16. 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+.

  17. 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

  18. 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.

  19. 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

  20. Micro-Raman studies of hydrous ferrous sulfates and jarosites.

    PubMed

    Chio, Chi Hong; Sharma, Shiv K; Muenow, David W

    2005-08-01

    Ferrous sulfates of various hydration states (FeSO(4) X xH(2)O; x=7, 4, 1) and jarosites (MFe(3)(SO(4))(2)(OH)(6); M=Na or K) were synthesized and studied by micro-Raman spectroscopy between 295 and 8K. Spectral analyses of the sulfate and water/hydroxyl vibrational modes are presented. Fingerprint regions attributed to the symmetric (nu(1)) and antisymmetric (nu(3)) stretching vibrations of the sulfate group are found to vary with the degree of hydration in hydrous ferrous sulfate. In jarosites, the Raman shift of the OH stretching mode is related to the type of alkali metal present between the tetrahedral and octahedral layers. The Raman technique can thus unambiguously identify ferrous sulfate of various hydration states and jarosites bearing different alkali metal ions.

  1. Nitrogen Isotopic Anomalies in a Hydrous Interplanetary Dust Particle

    NASA Technical Reports Server (NTRS)

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

    2005-01-01

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

  2. Single-crystal elasticity of hydrous wadsleyite by Brillouin scattering

    NASA Astrophysics Data System (ADS)

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

    2006-12-01

    Wadsleyite (β-Mg2SiO4) is the high-pressure polymorph of olivine that is expected to be a dominant mineral in the transition zone from 410 km to 520 km depth in the mantle. The elasticity of wadsleyite is crucial to constrain the mineralogy of the transition zone. Previous studies show wadsleyite can incorporate variable amounts of water up to 3.3 wt% of water (Kohlstedt et al. 1996; Inoue et al. 1995; Smyth et al. 1987, 1994). The effect of water on the bulk modulus of wadsleyite was studied by x-ray diffraction (Yusa and Inoue, 1997; Smyth et al. 2005) but no constraints on the shear modulus exist. We have measured the single-crystal elastic constants of hydrous wadsleyite with varying water content using Brillouin spectroscopy at ambient conditions. We carried out measurements for samples containing 0.3 wt%, 0.6 wt% and 1.6 wt% water using at least 2 crystal planes for each sample. By computing the aggregate elastic properties, we find that the bulk (K0S) and shear modulus (G0) of hydrous wadsleyite decrease linearly with water content according to the following relations: K0S=169.0-11.8X_W; G0=115.1-12.5X_W; where X_W is the water H2O weight percent. Compared with anhydrous wadsleyite, 1 wt% of water will lead to 7.0% decrease in bulk modulus, 10.9% decrease in shear modulus. Water has a greater effect on the elastic moduli of wadsleyite than that of olivine or ringwoodite. The olivine to wadsleyite phase transition is believed to be the origin of the seismic discontinuity near 410 km. Using these new results, the possible effect of water content on the velocity contrast across the 410-km discontinuity will be examined.

  3. 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)

  4. 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.

  5. 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

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

    NASA Astrophysics Data System (ADS)

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

    2016-09-01

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

  7. The use of anthracene as a model compound in a comparative study of hydrous pyrolysis methods for industrial waste remediation.

    PubMed

    Nkansah, Marian Asantewah; Christy, Alfred A; Barth, Tanja

    2011-07-01

    Polycyclic aromatic hydrocarbons are very stable compounds and tend to bioaccumulate in the environment due to their high degree of conjugation and aromaticity. Hydrous pyrolysis is explored as a technique for the treatment of industrial water containing PAH, using anthracene as a model compound. The reactivity of anthracene under a range of temperatures and durations are studied in this paper. Aliquots of 1.0-10.0mg of anthracene in a range of 1.0-5.0 mL of H(2)O are subjected to hydrous pyrolysis under varied conditions of temperature, reagents and duration. The conditions include oxidising systems comprising distilled water, hydrogen peroxide and Nafion-SiO(2) solid catalyst in water; and reducing systems of formic acid and formic acid/Nafion-SiO(2)/Pd-C catalysts to assess a range of redox reaction conditions. Oxygen in air played a role in some of the reaction conditions. Pyrolysed products were identified and quantified by the use of Gas Chromatography-Mass Spectrometry (GC-MS). The major products were anthrone, anthraquinone, xanthone from oxidation; and multiple hydro-anthracene derivatives from reductive hydogenation. The nature of reaction conditions influenced the extent of anthracene degradation. The products formed are more reactive (less stable) as compared to anthracene the starting material and will therefore be less persistent in the environment.

  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. Viscosity of Anhydrous and Hydrous Basalt Melts at High Pressures

    NASA Astrophysics Data System (ADS)

    Tinker, D.; Lesher, C. E.; Baxter, G. M.; Uchida, T.; Wang, Y.; Zhao, Y.

    2004-12-01

    We performed in situ falling-sphere experiments to determine the viscosity of anhydrous and hydrous basaltic (48 wt% SiO2) melts from 1.5 to 5.3 GPa between 1600 and 1840 K, using the T-25 MA8 multianvil apparatus at the GSECARS 13-ID-D beamline at the Advanced Photon Source, Argonne National Lab. These falling-sphere experiments included monitoring the simultaneous settling of Pt and Mo spheres, an approach that provides redundant viscosity measurements for individual experiments and offers the opportunity to recover simultaneously melt density. Our results show that the viscosity of anhydrous basalt melt decreases with pressure up to 5.3 GPa, with an activation volume for viscous flow of -8.1 to -9.5 cm3/mol between 2 and 5.3 GPa. The addition of a few wt. % water reduces melt viscosity by roughly 0.5 log units; however, there is no resolvable influence on activation volume. This negative pressure dependence is consistent with previous results for basaltic melts up to 3 GPa [1, 2], while the activation volume at low pressure is indistinguishable from the activation volume for O self-diffusion in the same bulk composition [3]. Application of the Eyring equation using O self-diffusion data for basaltic melt [3] predicts anhydrous melt viscosities that are 30-90% of the values determined in this study. This result is in stark contrast with our recent results for dacitic melt (68 wt% SiO2) melt [4], in which the Eyring equation overestimates viscosity by as much as 40% at pressures < 5 GPa. The limited utility of the Eyring equation for naturally-occurring silicate melts illustrates the difficulties in relating O self-diffusion to viscous flow in polymerized liquids. Adam-Gibbs theory [5] provides a means for addressing structural controls on these transport properties. The negative pressure dependence for anhydrous and hydrous basalt viscosity suggests that the extraction of partial melts from mantle source regions will be enhanced with pressure to 5.3 GPa. Future

  10. 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

  11. Fractional crystallization of primitive, hydrous arc magmas: an experimental study at 0.7 GPa

    NASA Astrophysics Data System (ADS)

    Nandedkar, Rohit H.; Ulmer, Peter; Müntener, Othmar

    2014-06-01

    Differentiation of mantle-derived, hydrous, basaltic magmas is a fundamental process to produce evolved intermediate to SiO2-rich magmas that form the bulk of the middle to shallow continental and island arc crust. This study reports the results of fractional crystallization experiments conducted in a piston cylinder apparatus at 0.7 GPa for hydrous, calc-alkaline to arc tholeiitic magmas. Fractional crystallization was approached by synthesis of starting materials representing the liquid composition of the previous, higher temperature experiment. Temperatures ranged from near-liquidus at 1,170 °C to near-solidus conditions at 700 °C. H2O contents varied from 3.0 to more than 10 wt%. The liquid line of descent covers the entire compositional range from olivine-tholeiite (1,170 °C) to high-silica rhyolite (700 °C) and evolves from metaluminous to peraluminous compositions. The following crystallization sequence has been established: olivine → clinopyroxene → plagioclase, spinel → orthopyroxene, amphibole, titanomagnetite → apatite → quartz, biotite. Anorthite-rich plagioclase and spinel are responsible for a marked increase in SiO2-content (from 51 to 53 wt%) at 1,040 °C. At lower temperatures, fractionation of amphibole, plagioclase and Fe-Ti oxide over a temperature interval of 280 °C drives the SiO2 content continuously from 53 to 78 wt%. Largest crystallization steps were recorded around 1,040 °C and at 700 °C. About 40 % of ultramafic plutonic rocks have to crystallize to generate basaltic-andesitic liquids, and an additional 40 % of amphibole-gabbroic cumulate to produce granitic melts. Andesitic liquids with a liquidus temperature of 1,010 °C only crystallize 50 % over an 280 °C wide range to 730 °C implying that such liquids form mobile crystal mushes (<50 % crystals) in long-lived magmatic systems in the middle crust, allowing for extensive fractionation, assimilation and hybridization with periodic replenishment of more mafic magmas

  12. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

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

    PubMed

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

    2016-01-01

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

  15. Bromine speciation in hydrous haplogranitic melts up to 7 GPa

    NASA Astrophysics Data System (ADS)

    Cochain, B.; de Grouchy, C.; Crepisson, C.; Kantor, I.; Irifune, T.; Sanloup, C.

    2013-12-01

    Halogens are minor volatiles in the Earth's mantle and crust, but they have significant and specific influences on magmatic and degassing processes. They also provide insights about subsurface magma movement and eruption likelihood in subduction-related volcanism. Their speciation in silicate melts affects volatile exsolution, rheology, and the thermodynamic properties of the melts but still remains relatively unknown. A few studies have explored halogen speciation at room conditions, i.e. in glasses but no firm conclusion has yet been reached. Furthermore, halogen speciation remains unexplored at high pressures and temperatures. In this work we investigate the speciation of Br in subduction-related melt (hydrous haplogranite melt) up to 1200°C and 7 GPa using X-ray absorption spectroscopy (XANES and EXAFS) at the Br K-edge. High P-T conditions were generated by the Paris-Edinburgh press. The use of nanocrystalline diamond capsules enabled us to avoid glitches in the EXAFS spectra. The results provide valuable information on Br speciation and its evolution with pressure. It gives insights into solubility mechanisms for halogens in magmas at depth and on their degassing from the melt. In addition, we were able to identify quench effects on the atomic environment of Br by comparison of high P-T in-situ spectra and ex-situ spectra recorded on quenched samples.

  16. 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.

  17. 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

  18. Phase H: A new high pressure phase of dense hydrous magnesium silicates in the lower mantle

    NASA Astrophysics Data System (ADS)

    Tsuchiya, J.; Tsuchiya, T.; Nishi, M.; Mookherjee, M.

    2014-12-01

    It has been believed that water is carried into the deep Earth's interior by hydrous minerals such as the dense hydrous magnesium silicates (DHMSs) in the descending cold plate. Recently, the new high pressure phase of DHMSs is theoretically predicted (Tsuchiya 2013) and experimentally confirmed in lower mantle pressure conditions above ~45 GPa (Nishi et al. 2014). This phase has MgSiO4H2 chemical composition and named as phase H. At the lower mantle pressure conditions, Al and H-bearing SiO2, δ-AlOOH, ɛ-FeOOH and phase H may be the potential hydrous phases in the subducting slabs. Interestingly, the crystal structure of these hydrous phases are almost same and have CaCl2 type structure. This suggests that these hydrous phases may be able to make the wide range of solid solution. Some experimental studies already reported that Al preferentially partitioned into phase H and the stability of phase H drastically increased by incorporation of Al (Nishi et al. 2014, Ohira et al. 2014). The density of subducted MORB is reported to be denser than that of pyrolite in the lower mantle. Therefore, there is a possibility that phase H containing Al and Fe in subducted MORB survive down to the bottom of lower mantle and the melting of phase H at the core mantle boundary may contribute to the cause of ultra-low velocity zones. In this study, we report the effects of Al and Fe on the stability of phase H, elasticity and seismic anisotropy of this new hydrous mineral using first principles calculation techniques and discuss the possible effects of this hydrous phase at the bottom of lower mantle.

  19. An Assessment of the Environmental Impacts from the Discharge of Bilge Water in the Norfolk Naval Station Harbor

    DTIC Science & Technology

    1991-08-01

    between the metal ion and specific surface sites. The hydrous metal oxides, clays and carbonates were typically the most common [ inorganic adsorbents... Hydrous metal oxides have the greatest affinity for ions because of their charged surface sites and high surface area. Hydrous metal oxides were...often present as coatings on particles such as organic " matter and clays. The dominant hydrous metal oxides in natural systems were the oxides of iron

  20. Mantle hydrous-fluid interaction with Archaean granite.

    NASA Astrophysics Data System (ADS)

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

    2012-04-01

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

  1. The density of dry and hydrous granitic magmas

    NASA Astrophysics Data System (ADS)

    Malfait, W. J.; Sanchez-Valle, C.; Seifert, R.; Petitgirard, S.; Perrillat, J.

    2011-12-01

    Large volumes of granitic magmas form through partial melting of the lower crust and are subsequently emplaced in the higher crustal levels [1]. In addition, granite-like liquids may form through partial melting of subducted sediments [2] or as an end-product of magmatic differentiation [3]. Moreover, water rich magmas of granitic composition are a major source of explosive volcanism. The physical properties of granitic melts, and particularly their density, are key controls on the migration rate and emplacement depth of granitic intrusions. However, because of the high viscosity of granitic liquids, density and compressibility measurements with the sink/float method and sound velocity measurements are challenging. As a result, the density and compressibility of dry and volatile-bearing granitic liquids is poorly constrained, particularly for the pressure-temperature conditions relevant for their formation and emplacement. In this study, we present in situ experimental data on the density of dry and hydrous haplogranitic melts (5 and 10 wt% water) at pressure and temperature conditions relevant for the crust and the subducting slab (1.0-2.7 GPa, 1350-1720 K). The experiments were performed with a panoramic Paris-Edinburgh press installed at the ID27 beamline of ESRF. The samples were contained in a cylindrical diamond capsule, capped with a platinum disk on either side, surrounded by hexagonal boron nitride (hBN) and placed inside a graphite heater and boron epoxy gasket. Pressure and temperature were determined from the X-ray diffraction patterns of hBN and platinum using the double-isochore method [4]. The density of the melts was determined from the X-ray absorption contrast between the sample and the diamond capsule (Mo edge, 20 keV). The molten state of the sample at the condition of the density measurements was verified by X-ray diffraction. The run products were analyzed by electron microprobe and infrared spectroscopy to verify the chemical composition and

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

    NASA Astrophysics Data System (ADS)

    Bonadiman, C.; Coltorti, M.

    2012-12-01

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

  3. 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...

  4. Predicted model for hydrous modified olivine (HyM-α)

    NASA Astrophysics Data System (ADS)

    Kudoh, Y.

    A possible structure for hydrous modified olivine (HyM-α) has been obtained by the subtraction of Mg3SiO5 from forsterite by crystallographic shear along a direction parallel to the [010] direction of olivine. The subtraction of Mg3SiO5 results in the subtraction of MgO from bulk chemistry (-Mg3SiO5=-Mg2SiO4-MgO). A possible structure for HyM-α thus obtained has the chemical formula Mg9Si5H2O20 (= 5 × Mg1.8SiH0.4O4) with monoclinic unit cell a=4.754 Å, b=10.19 Å, c=29.90 Å, ρ=3.126 g cm-3, and space group=Ac2m (no. 39). Since the X-ray powder diffraction pattern of HyM-α proposed in this study is very close to that of clinohumite, there is the possibility of this phase having been undiscovered. The humite group minerals and HyM-α proposed in this study make a homologous series as recombination structures: Mg(2m+n)SimH2nO2(2m+n) for the humite group and Mg(2m+n)Si(m+n)H2nO4(m+n) for HyM-α A characteristic feature is that Mg/Si > 2 for the humite group and Mg/Si < 2 for HyM-α. Forsterite specimens containing around 100 ppm H2O reported in mantle xenoliths might be the disordered case with n=1 and m=1200 of the humite group or HyM-α.

  5. 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.

  6. 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.

  7. 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.

  8. Inorganic nanomedicine--part 1.

    PubMed

    Sekhon, Bhupinder S; Kamboj, Seema R

    2010-08-01

    Inorganic nanomedicine refers to the use of inorganic or hybrid nanomaterials and nanosized objects to achieve innovative medical breakthroughs for drug and gene discovery and delivery, discovery of biomarkers, and molecular diagnostics. Potential uses for fluorescent quantum dots include cell labeling, biosensing, in vivo imaging, bimodal magnetic-luminescent imaging, and diagnostics. Biocompatible quantum dot conjugates have been used successfully for sentinel lymph node mapping, tumor targeting, tumor angiogenesis imaging, and metastatic cell tracking. Magnetic nanowires applications include biosensing and construction of nucleic acids sensors. Magnetic cell therapy is used for the repair of blood vessels. Magnetic nanoparticles (MNPs) are important for magnetic resonance imaging, drug delivery, cell labeling, and tracking. Superparamagnetic iron oxide nanoparticles are used for hyperthermic treatment of tumors. Multifunctional MNPs applications include drug and gene delivery, medical imaging, and targeted drug delivery. MNPs could have a vital role in developing techniques to simultaneously diagnose, monitor, and treat a wide range of common diseases and injuries. From the clinical editor: This review serves as an update about the current state of inorganic nanomedicine. The use of inorganic/hybrid nanomaterials and nanosized objects has already resulted in innovative medical breakthroughs for drug/gene discovery and delivery, discovery of biomarkers and molecular diagnostics, and is likely to remain one of the most prolific fields of nanomedicine.

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

    PubMed

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

    2012-12-01

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

  10. Polyaspartic acid facilitates oxolation within iron(iii) oxide pre-nucleation clusters and drives the formation of organic-inorganic composites

    NASA Astrophysics Data System (ADS)

    Scheck, J.; Drechsler, M.; Ma, X.; Stöckl, M. T.; Konsek, J.; Schwaderer, J. B.; Stadler, S. M.; De Yoreo, J. J.; Gebauer, D.

    2016-12-01

    The interplay between polymers and inorganic minerals during the formation of solids is crucial for biomineralization and bio-inspired materials, and advanced material properties can be achieved with organic-inorganic composites. By studying the reaction mechanisms, basic questions on organic-inorganic interactions and their role during material formation can be answered, enabling more target-oriented strategies in future synthetic approaches. Here, we present a comprehensive study on the hydrolysis of iron(iii) in the presence of polyaspartic acid. For the basic investigation of the formation mechanism, a titration assay was used, complemented by microscopic techniques. The polymer is shown to promote precipitation in partly hydrolyzed reaction solutions at the very early stages of the reaction by facilitating iron(iii) hydrolysis. In unhydrolyzed solutions, no significant interactions between the polymer and the inorganic solutes can be observed. We demonstrate that the hydrolysis promotion by the polymer can be understood by facilitating oxolation in olation iron(iii) pre-nucleation clusters. We propose that the adsorption of olation pre-nucleation clusters on the polymer chains and the resulting loss in dynamics and increased proximity of the reactants is the key to this effect. The resulting composite material obtained from the hydrolysis in the presence of the polymer was investigated with additional analytical techniques, namely, scanning and transmission electron microscopies, light microscopy, atomic force microscopy, zeta potential measurements, dynamic light scattering, and thermogravimetric analyses. It consists of elastic, polydisperse nanospheres, ca. 50-200 nm in diameter, and aggregates thereof, exhibiting a high polymer and water content.

  11. Adsorption mechanisms of selenium oxyanions at the aluminum oxide/water interface.

    PubMed

    Peak, Derek

    2006-11-15

    Sorption processes at the mineral/water interface typically control the mobility and bioaccessibility of many inorganic contaminants such as oxyanions. Selenium is an important micronutrient for human and animal health, but at elevated concentrations selenium toxicity is a concern. The objective of this study was to determine the bonding mechanisms of selenate (SeO4(2-) and selenite (SeO3(2-) on hydrous aluminum oxide (HAO) over a wide range of reaction pH using extended X-ray absorption fine structure (EXAFS) spectroscopy. Additionally, selenate adsorption on corundum (alpha-Al2O3) was studied to determine if adsorption mechanisms change as the aluminum oxide surface structure changes. The overall findings were that selenite forms a mixture of outer-sphere and inner-sphere bidentate-binuclear (corner-sharing) surface complexes on HAO, selenate forms primarily outer-sphere surface complexes on HAO, and on corundum selenate forms outer-sphere surface complexes at pH 3.5 but inner-sphere monodentate surface complexes at pH 4.5 and above. It is possible that the lack of inner-sphere complex formation at pH 3.5 is caused by changes in the corundum surface at low pH or secondary precipitate formation. The results are consistent with a structure-based reactivity for metal oxides, wherein hydrous metal oxides form outer-sphere complexes with sulfate and selenate, but inner-sphere monodentate surface complexes are formed between sulfate and selenate and alpha-Me2O3.

  12. Diamond Synthesis and Carbon Solubility in a Hydrous Granitoid System

    NASA Astrophysics Data System (ADS)

    Renfro, A.; Dobrzhinetskaya, L. P.

    2004-12-01

    An increasing number of UHP metamorphic terranes incorporated in collisional orogenic belts have been identified since the first discovery of diamonds within felsic metamorphic rocks of Kokchetav massif, Kazakhstan, extending up to ˜4000 km in length in the Dabie-SuLu-Qinling belt of China. Some have suggested that all orogenic belt diamonds formed from a carbonate or calc-alkaline melt similar to those derived from kimberlitic pipes, or alternatively that they formed from a carbon-enriched silicate melt with a granitoid bulk chemistry composition. Another group has suggested that orogenic belt diamonds crystallized from a COH-rich supercritical fluid. While the diversity of the minor components accompanying the SiO2-dominated inclusions from Kokchetav diamonds, as well as the presence of cavities bearing traces of a former fluid, suggest the idea of diamond growth from a COH fluid, a Si-rich melt as a source for diamond formation cannot be ruled out. Although many experiments were performed on diamond synthesis and on the petrology of diamond-bearing rocks, no consensus has been reached as to which of the mentioned growth media is correct to explain orogenic belt diamond formation. We report here the results of an experimental program undertaken to determine the critical point of the Si-Al-K-C-H2O system (and thus, to distinguish a melt environment from a fluid one) and to provide an understanding of how diamond is crystallized in hydrous subducted felsic continental crust. Carbon solubility in these systems was qualitatively determined based on the observed diamond growth rates. Experiments were performed at in a Walker-style multianvil apparatus at P=7 GPa and T=1500-1700° C with SiO2 ranging from 90 wt. %, imitating diamondiferous quartzite, to 62 wt. %, imitating a wide range of feldspathic diamondiferous gneisses. An additional parameter, oxygen fugacity, was also varied to test its affects on the solubility of carbon in Si-rich melt/fluid.

  13. 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.

  14. 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

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

    NASA Astrophysics Data System (ADS)

    Ueki, K.; Iwamori, H.

    2015-12-01

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

  16. 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

  17. Method for plating with metal oxides

    SciTech Connect

    Silver, Gary L.; Martin, Frank S.

    1994-08-23

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

  18. Method for plating with metal oxides

    SciTech Connect

    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.

  19. 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.

  20. 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.

  1. Effects of inorganic electrolyte anions on enrichment of Cu(II) ions with aminated Fe3O4/graphene oxide: Cu(II) speciation prediction and surface charge measurement.

    PubMed

    Hu, Xin-jiang; Liu, Yun-guo; Zeng, Guang-ming; Wang, Hui; You, Shao-hong; Hu, Xi; Tan, Xiao-fei; Chen, An-wei; Guo, Fang-ying

    2015-05-01

    The present work evaluated the effects of six inorganic electrolyte anions on Cu(II) removal using aminated Fe3O4/graphene oxide (AMGO) in single- and multi-ion systems. A 2(6-2) fractional factorial design (FFD) was employed for assessing the effects of multiple anions on the adsorption process. The results indicated that the Cu(II) adsorption was strongly dependent on pH and could be significantly affected by inorganic electrolyte anions due to the changes in Cu(II) speciation and surface charge of AMGO. In the single-ion systems, the presence of monovalent anions (Cl(-), ClO4(-), and NO3(-)) slightly increased the Cu(II) adsorption onto AMGO at low pH, while the Cu(II) adsorption was largely enhanced by the presence of SO4(2-), CO3(2-), and HPO4(2-). Based on the estimates of major effects and interactions from FFD, the factorial effects of the six selected species on Cu(II) adsorption in multi-ion system were in the following sequence: HPO4(2-)>CO3(2-)>Cl(-)>SO4(2-)>NO3(-)=ClO4(-), and the combined factors of AD (Cl(-)×SO4(2-)) and EF (Cl(-)×SO4(2-)) had significant effects on Cu(II) removal.

  2. 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

  3. 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.

  4. 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.

  5. 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

  6. SEM observation of hydrous superabsorbent polymer pretreated with room-temperature ionic liquids.

    PubMed

    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 ([P(4, 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.

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

    PubMed

    Tannenbaum, E; Kaplan, I R

    1985-10-24

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

  8. Infrared diffuse reflectance spectra of carbonaceous chondrites: Amount of hydrous minerals

    NASA Technical Reports Server (NTRS)

    Miyamoto, M.; Zolensky, M. E.

    1994-01-01

    Infrared diffuse reflectance spectra (2.53-25 microns) of some carbonaceous (C) chondrites were measured. The integrated intensity of the absorption bands near 3 microns caused by hydrous minerals were compared with the modal content of hydrous minerals for the meteorites. The CM and CI chondrites show larger values of the intergated intensity than those of the unique C chondrites Y82162, Y86720 and B7904, suggesting that the amount of hydrous minerals in the CM and CI chondrites is larger, which supports the contention that hydrous minerals were dehydrated by thermal metamorphism in the unique chondrites. Orgueil (CI) has the largest value of the integrated intensity among the C chondrites we measured and shows a sharp absorption band at 3685/cm (2.71 microns) that is not seen in the spectra of the CM chondrites. There is an excellent correlation between the observed hydrogen content in C chondrites and the integrated intensity. The CM chondrites show a wide variation in the strength of absorption bands at 1470/cm (6.8 microns), despite the similarity in absorption features near 3 micron for all CM chondites. The 1470/cm band could be due to the presence of some hydrocarbons but may also be a result of terrestrial alteration processes.

  9. Mineralogical, Spectral, and Compositional Changes During Heating of Hydrous Carbonaceous Chondrites

    NASA Technical Reports Server (NTRS)

    Nakamura, T.; Matsuoka, M.; Yamashita, S.; Sato, Y.; Mogi, K.; Enokido, Y.; Nakata, A.; Okumura, S.; Furukawa, Y.; Zolensky, M.

    2017-01-01

    Hydrous carbonaceous chondrites experienced hydration and subsequent dehydration by heating, which resulted in a variety of mineralogical and spectral features [e. g., 1-6]. The degree of heating is classified according to heating stage (HS) II to IV based on mineralogy of phyllosilicates [2], because they change, with elevating temperature, to poorly crystal-line phases and subsequently to aggregates of small secondary anhydrous silicates of mainly olivine. Heating of hydrous carbonaceous chondrites also causes spectral changes and volatile loss [3-6]. Experimental heating of Murchison CM chondrite showed flattening of whole visible-near infrared spectra, especially weakening of the 3µm band strength [1, 4, 7]. In order to understand mineralogical, spectral, and compositional changes during heating of hydrous carbonaceous chondrites, we have carried out systematic investigation of mineralogy, reflectance spectra, and volatile composition of hydrated and dehydrated carbonaceous chondrites as well as experimentally-heated hydrous carbonaceous chondrites. In addition, we investigated reflectance spectra of tochilinite that is a major phase of CM chondrites and has a low dehydration temperature (250degC).

  10. 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.

  11. 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

    2015-06-02

    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.

  12. 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

  13. 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.

  14. Biosynthetic inorganic chemistry.

    PubMed

    Lu, Yi

    2006-08-25

    Inorganic chemistry and biology can benefit greatly from each other. Although synthetic and physical inorganic chemistry have been greatly successful in clarifying the role of metal ions in biological systems, the time may now be right to utilize biological systems to advance coordination chemistry. One such example is the use of small, stable, easy-to-make, and well-characterized proteins as ligands to synthesize novel inorganic compounds. This biosynthetic inorganic chemistry is possible thanks to a number of developments in biology. This review summarizes the progress in the synthesis of close models of complex metalloproteins, followed by a description of recent advances in using the approach for making novel compounds that are unprecedented in either inorganic chemistry or biology. The focus is mainly on synthetic "tricks" learned from biology, as well as novel structures and insights obtained. The advantages and disadvantages of this biosynthetic approach are discussed.

  15. Investigations of inorganic and hybrid inorganic-organic nanostructures

    NASA Astrophysics Data System (ADS)

    Kam, Kinson Chihang

    This thesis focuses on the exploratory synthesis and characterization of inorganic and hybrid inorganic-organic nanomaterials. In particular, nanostructures of semiconducting nitrides and oxides, and hybrid systems of nanowire-polymer composites and framework materials, are investigated. These materials are characterized by a variety of techniques for structure, composition, morphology, surface area, optical properties, and electrical properties. In the study of inorganic nanomaterials, gallium nitride (GaN), indium oxide (In2O3), and vanadium dioxide (VO2) nanostructures were synthesized using different strategies and their physical properties were examined. GaN nanostructures were obtained from various synthetic routes. Solid-state ammonolysis of metastable gamma-Ga2O 3 nanoparticles was found to be particularly successful; they achieved high surface areas and photoluminescent study showed a blue shift in emission as a result of surface and size defects. Similarly, In2O3 nanostructures were obtained by carbon-assisted solid-state syntheses. The sub-oxidic species, which are generated via a self-catalyzed vapor-liquid-solid mechanism, resulted in 1D nanostructures including nanowires, nanotrees, and nanobouquets upon oxidation. On the other hand, hydrothermal methods were used to obtain VO2 nanorods. After post-thermal treatment, infrared spectroscopy demonstrated that these nanorods exhibit a thermochromic transition with temperature that is higher by ˜10°C compared to the parent material. The thermochromic behavior indicated a semiconductor-to-metal transition associated with a structural transformation from monoclinic to rutile. The hybrid systems, on the other hand, enabled their properties to be tunable. In nanowire-polymer composites, zinc oxide (ZnO) and silver (Ag) nanowires were synthesized and incorporated into polyaniline (PANI) and polypyrrole (PPy) via in-situ and ex-situ polymerization method. The electrical properties of these composites are

  16. 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

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

    NASA Astrophysics Data System (ADS)

    Li, Yuan

    2014-11-01

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

  18. 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.

  19. Analytical methods for SiO2 and other inorganic oxides in titanium dioxide or certain silicates for food additive specifications.

    PubMed

    Mutsuga, Motoh; Sato, Kyoko; Hirahara, Yoshichika; Kawamura, Yoko

    2011-04-01

    An analytical method has been developed for the detection of SiO(2) and other oxides in titanium dioxide and certain silicates used in food additives using inductively coupled plasma (ICP) atomic emission spectrometry without hydrofluoric acid. SiO(2) and other oxides in titanium dioxide or certain silicates were resolved by alkali fusion with KOH and boric acid and then dissolved in dilute hydrochloric acid as a test solution for ICP. The recovery of SiO(2) and Al(2)O(3) added at 0.1 and 1.0%, respectively, in TiO(2) was 88-104%; coefficient of variation was <4%. The limit of determination of SiO(2) and Al(2)O(3) was about 0.08%, and the accuracy of the ICP method was better than that of the Joint FAO/WHO Expert Committee on Food Additives (JECFA) test method. The recovery of SiO(2) and other oxides in silicates was 95-107% with a coefficient of variation of <4%. Using energy dispersive X-ray fluorescence spectrometry (EDX) with fundamental parameter determination, the content of SiO(2) and other oxide in titanium dioxide and silicate showed good agreement with the ICP results. ICP with alkali fusion proved suitable as a test method for SiO(2), Al(2)O(3) and other oxides in titanium dioxide and certain silicates, and EDX proves useful for screening such impurities in titanium dioxide and componential analysis of certain silicates.

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

    SciTech Connect

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

    2015-09-25

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

  1. Applications of inorganic nanoparticles in diabetes

    NASA Astrophysics Data System (ADS)

    Elhabush, Nada Atiya Omar

    Diabetes Mellitus (DM) is an endocrine and metabolic disease that has become a global emergency because of the rapid rise in morbidity and mortality rates worldwide. Since the direct delivery of biomolecules, such as insulin, to treat DM is inefficient and subjected to enzymatic degradation, nanotechnology and nanomedicine research have been devoted to the development of more effective methods to treat DM. Nanoparticles (NP), organic, inorganic, or hybrid, have served as potential carrier for safe and efficient transport for insulin. Additionally, several NP have biological activities that help treat and/or prevent DM and diabetes complications, such as antioxidant, anti-apoptotic, or insulin-mimetic activities. Moreover, physicochemical properties of some NP allow them to be used in diagnostic tools for potential diagnosis or monitoring purposes. This work highlights the applications of inorganic NP such as, gold, selenium, silver, calcium phosphate, zinc oxide, cerium oxide, and iron oxide and in the treatment or diagnosis of DM.

  2. 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)

  3. 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.

  4. Partitioning of Trace Elements Between Hydrous Minerals and Aqueous Fluids : a Contribution to the Chemical Budget of Subduction Zones

    NASA Astrophysics Data System (ADS)

    Daniel, I.; Koga, K. T.; Reynard, B.; Petitgirard, S.; Chollet, M.; Simionovici, A.

    2006-12-01

    Subduction zones are powerful chemical engines where the downgoing lithosphere reacts with asthenospheric mantle and produces magmas. Understanding this deep recycling system is a scientific challenge requiring multiple approaches. Among those, it appears that we lack basic information on the composition of the fluid that begins the process of material transfer in subduction zones. Indeed, no pristine fluid sample has yet been collected from this particular environment. Albeit challenging, the alternative would be experimental study of fluids under the appropriate conditions. Consequently, we developed an experimental protocol to measure the concentration of aqueous fluids equilibrated with minerals up to pressures (P) of 5 GPa, at least and temperatures (T) of 550 C. This includes syntheses at high-P and -T conditions, and determination of the fluid composition. Syntheses were performed in a large volume belt-type press at the conditions, 2-5 GPa and ca. 550 C. Oxides or minerals were loaded with water in a gold capsule sealed afterwards. Presence of free fluid during experiments could be confirmed by direct observation of fluid release from the sealed capsule upon puncturing. The composition in trace elements of the fluids that were equilibrated at high-P and -T with minerals was reconstructed from that of the precipitates deposited at the surface of minerals after evaporation of the capsule. The precipitates were dissolved and analyzed by a leaching technique detailed in Koga et al. (2005). Two hydrous minerals of prime interest for subductions were sofar investigated: the high-pressure variety of serpentine, antigorite, and talc. The partitioning coefficients of a series of trace-elements will be presented, as well as their evolution as a function of pressure. Consequences for the composition of the fluids released during the dehydration of hydrous metamorphic minerals will be drawn. Those measurements are unlikely to be feasible at pressures in excess of 5 GPa

  5. 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.

  6. 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.

  7. Evidence for the late formation of hydrous asteroids from young meteoritic carbonates.

    PubMed

    Fujiya, Wataru; Sugiura, Naoji; Hotta, Hideyuki; Ichimura, Koji; Sano, Yuji

    2012-01-17

    The accretion of small bodies in the Solar System is a fundamental process that was followed by planet formation. Chronological information of meteorites can constrain when asteroids formed. Secondary carbonates show extremely old (53)Mn-(53)Cr radiometric ages, indicating that some hydrous asteroids accreted rapidly. However, previous studies have failed to define accurate Mn/Cr ratios; hence, these old ages could be artefacts. Here we develop a new method for accurate Mn/Cr determination, and report a reliable age of 4,563.4+0.4/-0.5 million years ago for carbonates in carbonaceous chondrites. We find that these carbonates have identical ages, which are younger than those previously estimated. This result suggests the late onset of aqueous activities in the Solar System. The young carbonate age cannot be explained if the parent asteroid accreted within 3 million years after the birth of the Solar System. Thus, we conclude that hydrous asteroids accreted later than differentiated and metamorphosed asteroids.

  8. Water Speciation and properties of hydrous model basalt melt at high pressure

    NASA Astrophysics Data System (ADS)

    Bajgain, S. K.; Karki, B. B.

    2013-12-01

    Silicate melts in the Earth's interior are known/expected to be hydrous. Water can make major impact on physical properties including the structure, density, and mobility of melts. The behavior of relevant hydrous melts over most of the mantle pressure regime is poorly constrained. Water solubility increases rapidly with increasing pressure at low pressure [1] and a complete miscibility of liquid MgSiO3 and H2O has been suggested based on high-pressure simulations [2]. We have recently performed first principle molecular dynamics simulations of hydrous model basalt melt at high pressure. Our results show that with increasing pressure, the partial molar volume of water in the melt asymptotically approaches to that of pure water, and both the volumes become identical after certain point. Water is predicted to dissolve in the form of hydroxyls and water molecules at low pressure and as more extended structures at high pressure. The simulated basalt-H2O system commences to behave ideally at pressures above 10 GPa. In contrast, the simulated SiO2-H2O and MgSiO3-H2O systems approach to an ideal limit at much higher pressures of 50 GPa or above. These results imply an unlimited solubility of water in in silicate melts and the water solubility rather appears to be insensitive of composition at high pressure. Existence of water-rich silicate melts over most of the mantle in early history could have made substantial contribution to the origin of hydrosphere [3]. [1] Shen, A. H., and H. Keppler (1997), Direct observation of complete miscibility in the Albite-H2O system, Nature, 385, 710-712. [2] Mookherjee, M., L. Stixrude, and B. Karki (2008), Hydrous silicate melt at high pressure, Nature, 452, 983-986. [3] Matsui, T., and Y. Abe (1986), Evolution of an impact-induced atmosphere and magma ocean on the accreting Earth, Nature, 319, 303-305.

  9. Detectability of hydrous minerals using ONC-T camera onboard the Hayabusa2 spacecraft

    NASA Astrophysics Data System (ADS)

    Kameda, S.; Suzuki, H.; Cho, Y.; Koga, S.; Yamada, M.; Nakamura, T.; Hiroi, T.; Sawada, H.; Honda, R.; Morota, T.; Honda, C.; Takei, A.; Takamatsu, T.; Okumura, Y.; Sato, M.; Yasuda, T.; Shibasaki, K.; Ikezawa, S.; Sugita, S.

    2015-10-01

    The Hayabusa2 spacecraft has three framing cameras (ONC-T, ONC-W1, and ONC-W2) for optical navigation to asteroid 1999 JU3. The ONC-T is a telescopic camera with seven band-pass filters in the visible and near-infrared range. These filters are placed on a wheel, which rotates to put a selected filter for different observations, enabling multiband imaging. Previous ground-based observations suggesting that hydrous materials may be present on the surface of 1999 JU3 and distributed in relatively limited areas. The presence of hydrous minerals indicates that this asteroid experienced only low to moderate temperatures during its formation, suggesting that primordial materials are preserved. In order to find the best sampling sites, we will perform reflectance spectroscopic observations using the ONC-T near the asteroid after arrival. Finding regions rich in hydrous minerals is the key for this remote sensing observation. In preparation for this, we conducted ground-based experiments for the actual ONC-T flight model to confirm the detectability of the absorption band of Fe-rich serpentine. As a result, we detected the absorption band near 0.7 μm by reflectance spectroscopy of CM2 chondrites, such as Murchison and Nogoya, which are known to contain the Fe-rich serpentine, and did not detect any 0.7 μm absorption in Jbilet Winselwan CM2 chondrite with decomposed Fe-rich serpentine.

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. Inorganic and Organometallic Polymers

    NASA Astrophysics Data System (ADS)

    Chandrasekhar, Vadapalli

    This textbook is intended to give an understanding of the basic principles that constitute the field of non-conventional polymers containing inorganic and organometalic units as the repeating units. Each chapter will be self-explanatory with a good background so that it can be easily understood at the senior undergraduate level. The principles involved in the preparation of these polymers, their characterisation and their applications will be discussed. Basic inorganic chemistry required for the understanding of each topic is presented so that the content of the chapter is readily understood.

  15. Experimental constraints on the genesis of hydrous arc dacites

    NASA Astrophysics Data System (ADS)

    Blatter, D. L.; Sisson, T. W.; Hankins, W. B.

    2015-12-01

    Shallow, pre-eruptive storage conditions are well known for dacitic magmas of the Cascade arc through melt inclusions, FeTi oxides, and experiments. Zircon ages indicate protracted (>105 yrs) incubation for some Cascade dacites, but their origins in the deep crust have not been established. Accordingly, we report experimental results identifying the P-T-H2O conditions under which such liquids could segregate from (hornblende-) gabbroic sources. Two compositions were investigated: (1) MSH-Yn dacite (SiO2: 65 wt%) from Mount St. Helens' voluminous Yn tephra, and (2) MSH-Yn + 10% cpx to force saturation with cpx and locate the cpx + melt = amphibole peritectic. H2O-undersaturated (3-9 wt% H2O) piston cylinder experiments were conducted at pressures, temperatures, and fO2 appropriate for the lower to middle crust (400 to 900 MPa, 825 to 1100°C, and ReReO2). Results for MSH-Yn indicate near-liquidus equilibrium with a cpx-free hornblende-gabbro residue (amphibole, plagioclase, magnetite, +/- opx and ilmeno-hematite) with 6-7 wt% H2O, 925°C, and 700-900 MPa. Opx disappears down-temperature consistent with the reaction opx + melt = amphibole. Cpx-added phase relations are similar in that once ~10% cpx crystallizes, multiple saturation is attained with cpx, amphibole, and plagioclase, +/- opx, at 6-7 wt% H2O, 950°C, and 700-900 MPa. Plagioclase-amphibole-cpx saturated liquids diverge from plagioclase-amphibole-opx saturated liquids, consistent with the MSH-Yn dacite composition marking a (pseudo-invariant) distributary reaction point where amphibole appears down-temperature and opx + cpx cease to coexist. Liquid compositions and temperatures stall at reaction points, irrespective of whether the source is crystallizing or melting, accounting for the compositional and thermal uniformity of voluminous dacites that feed into the shallow storage regions of arc volcanoes.

  16. Impacts of organic and inorganic fertilizers on nitrification in a cold climate soil are linked to the bacterial ammonia oxidizer community.

    PubMed

    Fan, Fenliang; Yang, Qianbao; Li, Zhaojun; Wei, Dan; Cui, Xi'an; Liang, Yongchao

    2011-11-01

    The microbiology underpinning soil nitrogen cycling in northeast China remains poorly understood. These agricultural systems are typified by widely contrasting temperature, ranging from -40 to 38°C. In a long-term site in this region, the impacts of mineral and organic fertilizer amendments on potential nitrification rate (PNR) were determined. PNR was found to be suppressed by long-term mineral fertilizer treatment but enhanced by manure treatment. The abundance and structure of ammonia-oxidizing bacterial (AOB) and archaeal (AOA) communities were assessed using quantitative polymerase chain reaction and denaturing gradient gel electrophoresis techniques. The abundance of AOA was reduced by all fertilizer treatments, while the opposite response was measured for AOB, leading to a six- to 60-fold reduction in AOA/AOB ratio. The community structure of AOA exhibited little variation across fertilization treatments, whereas the structure of the AOB community was highly responsive. PNR was correlated with community structure of AOB rather than that of AOA. Variation in the community structure of AOB was linked to soil pH, total carbon, and nitrogen contents induced by different long-term fertilization regimes. The results suggest that manure amendment establishes conditions which select for an AOB community type which recovers mineral fertilizer-suppressed soil nitrification.

  17. 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.

  18. 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

  19. 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.

  20. Protection from inorganic mercury effects on the in vivo dopamine release by ionotropic glutamate receptor antagonists and nitric oxide synthase inhibitors.

    PubMed

    Vidal, Lucía; Durán, Rafael; Faro, Lilian F; Campos, Francisco; Cervantes, Rosa C; Alfonso, Miguel

    2007-09-05

    The possible role of ionotropics glutamate receptors on the HgCl(2)-induced dopamine (DA) release from rat striatum was investigated by using in vivo brain microdialysis technique after administration of selective NMDA and AMPA/Kainate receptors antagonists dizocilpine (MK-801), D (-)-2-amino-5-phoshonopentanoic acid (AP5), and 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX). Moreover, we have also studied the effects of nitric oxide synthase (NOS) inhibitors L-nitro-arginine methyl ester (L-NAME) and 7-nitro-indazol (7-NI) on HgCl(2)-induced DA release. Intraestriatal infusion of 1mM HgCl(2) increased striatal DA to 1717.2+/-375.4% respect to basal levels. Infusion of 1mM HgCl(2) in 400 microM MK-801 pre-treated animals produced an increase on striatal DA levels 61% smaller than that induced in non-pre-treated animals. In the case of AP5, this treatment reduced 92% the increase produced by HgCl(2) as compared to non-pre-treated rats. Nevertheless, the administration of CNQX did not produce any effect on HgCl(2)-induced dopamine release. Intrastriatal infusion of 1mM HgCl(2) in 100 microM L-NAME pre-treated animals produced an increase on extracellular DA levels 82% smaller than produced by HgCl(2) alone. In addition, the pre-treatment with 7-NI reduced 90% the increase produced by infusion of HgCl(2) alone in rats. Thus, HgCl(2)-induced DA release could be produced at last in part, by overstimulation of NMDA receptors with NO production, since administration of NMDA receptor antagonists and NOS inhibitors protected against HgCl(2) effects on DA release.

  1. 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

  2. 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

  3. Polyhedra in (inorganic) chemistry.

    PubMed

    Alvarez, Santiago

    2005-07-07

    A systematic description of polyhedra with varying degrees of regularity is illustrated with examples of chemical structures, mostly from different fields of Inorganic Chemistry. Also the geometrical relationships between different polyhedra are highlighted and their application to the analysis of complex structures is discussed.

  4. 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

  5. Al-bearing dense hydrous minerals under mantle transition zone and uppermost lower mantle conditions

    NASA Astrophysics Data System (ADS)

    Inoue, T.; Hayashi, K.; Yurimoto, H.

    2013-12-01

    Subducting slabs are supplying water into the deep mantle, and some hydrous minerals may be present in the mantle transition zone and even in the uppermost lower mantle. The water storage capacities of mantle minerals are supposed to be significantly coupled with Al by a substitution with Mg2+, Si4+ or Mg2+ + Si4+, because Al3+ is the trivalent cation, and H+ is the monovalent cation. In this study, we have examined the effect of Al for the water content and the stability of some hydrous phases in the system MgO - Al2O3 - SiO2 - H2O in the mantle transition zone and the uppermost lower mantle condition. The experiments were conducted at 20 - 25 GPa and 1873 - 2273K by MA8-type (KAWAI-type) high pressure apparatus. The samples were sealed by AuPd capsule to prevent the loss of water, and the temperatures were measured by WRe thermocouple. The charges were heated for 1 hour in the desired P-T conditions, and then quenched at the rate of ~1000K/sec by tuning off the electric power supply. After releasing the press load for several hours, the run products were recovered, and then the recovered samples were polished to measure the chemical composition and the H2O contents.. We succeeded to synthesize the Al-bearing hydrous minerals (Al-bearing phase B, Al-bearing superhydrous phase B, Mg-Si bearing δ-AlOOH), and found that the significant coupling of H and Al were occurred in these minerals. The chemical compositions and the lattice parameters are examined by SEM-EDS and microfocus-XRD, and the H2O contents were measured by SIMS. The present chemical formula and the lattice parameters were compared to discuss about the difference between the pure chemical forms. Still more, the substitution mechanisms were considered basically by the chemical compositions and the information of the crystal structures. Our study suggests that water can be stored in the mantle transition zone and the uppermost lower mantle in the form of Al-bearing hydrous minerals or nominally anhydrous

  6. 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.

  7. Hydrous and anhydrous garnet-bearing mantle xenoliths from Hawaii: Isotopic Heterogeneity?

    NASA Astrophysics Data System (ADS)

    Mukherjee, S.; Bizimis, M.; Keshav, S.; Sen, G.

    2003-12-01

    This study focuses on the petrography, major element mineral chemistry, and bulk-rock trace element and Sr-Nd isotopes compositions of a suite of garnet-bearing xenoliths from Oahu, Hawaii, in an attempt to answer the following questions: (1) Are these xenoliths restites, cumulates, or frozen melts? (2) Are they related to Koolau-like (shield stage) magmas or post-erosional Honolulu Volcanics (HV)-type magmas? Large clinopyroxene (cpx) is the dominant phase; however, large garnet (gt), orthopyroxene (opx), olivine (ol), and spinel (sp) are also present. Some xenoliths also have trace (less than 1 percent) amounts of phlogopite of different shapes and sizes. Cpx has exsolved opx, sp, and gt. Mineral chemically, cpx is a low-Cr, high-Al, Na, Ti, and Fe/Mg variety. Garnet is a low-Cr and high Fe/Mg type. The Mg#s of cpx and gt range from 74-85 and 61-74, respectively. The Mg# of opx ranges from ~80-84. Spinels are of the pleonaste type. Chemical traits of cpx, gt, and sp indicate that these xenoliths cannot be treated as either restites or frozen melts. Post-exsolution and "igneous" stage temperatures based on cpx-gt thermometry range from ~ 950-1350oC and ~ 1290-1470oC. Cpx and gt are in Mg# equilibrium with each other. Opx has not equilibrated with cpx or gt in terms of Mg/Fe. The anhydrous xenoliths are distinct from the Pacific-MORB and Koolau, but are virtually identical to the HV lavas, confirming previous suggestions that the garnet pyroxenites are genetically related to parental magmas. However, some hydrous xenoliths have more radiogenic Sr isotope (for a given Nd) than both HV and the anhydrous xenoliths, and fall outside the compositions of the Hawaiian lavas in the Sr-Nd isotope space. From Sr-Nd data on these xenoliths, the following becomes clear: (1) All the anhydrous and some hydrous xenoliths pyroxenite are virtually identical to the HV; (2) Higher Sr isotope compositions of the hydrous variety indicates that water-bearing phases may be partially

  8. Energetic comparison between photoinduced electron-transfer reactions from NADH model compounds to organic and inorganic oxidants and hydride-transfer reactions from NADH model compounds to p-benzoquinone derivatives

    SciTech Connect

    Fukuzumi, S.; Koumitsu, S.; Hironaka, K.; Tanaka, T.

    1987-01-21

    Kinetic studies on photoinduced electron-transfer reactions from dihydropyridine compounds (PyH/sub 2/) as being NADH model compounds to organic and inorganic oxidants and hydride-transfer reactions from PyH/sub 2/ to p-benzoquinone derivatives (Q) in the absence and presence of Mg/sup 2 +/ ion are reported by determining over 150 rate constants. These results, combined with the values of Gibbs energy change of the photoinduced electron-transfer reactions as well as those of each step of the hydride-transfer reactions as being the e/sup -/-H/sup +/-e/sup -/ sequence, which are determined independently, revealed that the rate constants of the photoinduced electron-transfer reactions obey the Rehm-Weller-Gibbs energy relationship and that the activation barrier of the hydride-transfer reactions from PyH/sub 2/ to Q is dependent solely on the Gibbs energy changes of the initial electron transfer from PyH/sub 2/ to Q and the following proton transfer from PyH/sub 2//sup .+/ to Q/sup .-/ and thus independent of the Gibbs energy change of the final electron transfer from PyH/sup ./ to QH/sup ./. The retarding effect of Mg/sup 2 +/ ion observed on the photoinduced electron transfer and hydride-transfer reactions of PyH/sub 2/ is ascribed to the positive shifts of the redox potentials of the ground and excited states of PyH/sub 2/ due to the complex formation with Mg/sup 2 +/ ion.

  9. 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.

  10. 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.

  11. Inorganic Chemistry by Gary Wulfsberg

    NASA Astrophysics Data System (ADS)

    Ackermann, Martin N.

    2000-11-01

    Inorganic Chemistry is an interesting new option for teachers of advanced inorganic courses and offers the possibility of serving an introductory course as well. Since PDIC first appeared, more authors have adopted the approach of developing descriptive inorganic chemistry around common principles instead of a group-by-group treatment, which makes this text less of a departure from the traditional than PDIC was. Still, Wulfsberg offers an original and engaging perspective on inorganic chemistry. Even if this text is not adopted for a course, it deserves a place on the shelf of every teacher of inorganic chemistry, where it will be a valuable resource.

  12. 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.

  13. Inorganic biomimetic nanostructures.

    PubMed

    Levine, Lauren A; Williams, Mary Elizabeth

    2009-12-01

    Supramolecular structures modeled after biological systems (DNA and enzymes) are being developed to simultaneously mimic natural biological functions including catalysis, information storage, and self-assembly and to engineer novel electronic and magnetic properties. Structural mimics of nucleic acids containing multiple metal-coordinating ligands, and comprising natural and artificial bases or completely synthetic systems, create stable double-stranded structures with new electronic, spectroscopic, and magnetic properties. Supramolecular inorganic mimics of enzymatic function, including metallonucleases and metalloproteases, have begun to be constructed. Alternatively, metal-organic-frameworks have potential as artificial catalysts with substrate-specificity and size-selectivity analogous to biological processes. This review describes some of the recent themes in inorganic supramolecular systems that aim to mimic and exploit nature's ability to self-assemble polyfunctional architectures for new materials and biological applications.

  14. 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.

  15. Remote pulsed laser Raman spectroscopy system for detecting water, ice, and hydrous minerals

    NASA Astrophysics Data System (ADS)

    Garcia, Christopher S.; Abedin, M. Nurul; Sharma, Shiv K.; Misra, Anupam K.; Ismail, Syed; Singh, Upendra N.; Refaat, Tamer F.; Elsayed-Ali, Hani E.; Sandford, Steve P.

    2006-08-01

    For exploration of planetary surfaces, detection of water and ice is of great interest in supporting existence of life on other planets. Therefore, a remote Raman spectroscopy system was demonstrated at NASA Langley Research Center in collaboration with the University of Hawaii for detecting ice-water and hydrous minerals on planetary surfaces. In this study, a 532 nm pulsed laser is utilized as an excitation source to allow detection in high background radiation conditions. The Raman scattered signal is collected by a 4-inch telescope positioned in front of a spectrograph. The Raman spectrum is analyzed using a spectrograph equipped with a holographic super notch filter to eliminate Rayleigh scattering, and a holographic transmission grating that simultaneously disperses two spectral tracks onto the detector for higher spectral range. To view the spectrum, the spectrograph is coupled to an intensified charge-coupled device (ICCD), which allows detection of very weak Stokes line. The ICCD is operated in gated mode to further suppress effects from background radiation and long-lived fluorescence. The sample is placed at 5.6 m from the telescope, and the laser is mounted on the telescope in a coaxial geometry to achieve maximum performance. The system was calibrated using the spectral lines of a Neon lamp source. To evaluate the system, Raman standard samples such as calcite, naphthalene, acetone, and isopropyl alcohol were analyzed. The Raman evaluation technique was used to analyze water, ice and other hydrous minerals and results from these species are presented.

  16. Enhanced Lithium-ion intercalation properties of coherent hydrous vanadium pentoxide-carbon cryogels nanocomposites

    SciTech Connect

    Pan, Anqiang; Liu, Dawei; Zhou, Xiaoyuan; Garcia, Betzaita Betalla; Liang, Shu-quan; Liu, Jun; Cao, Guozhong

    2010-06-01

    Coherent hydrous vanadium pentoxide (V2O5•nH2O) - carbon cryogels (CCs) nanocomposites were synthesized by electrodeposition of vanadium pentoxide onto the porous carbon scaffold which was derived from resorcinol (R) and formaldehyde (F) organic hydrogels. As-fabricated nanocomposites were characterized by scanning electron microscopy (SEM), along with EDAX and nitrogen sorption isotherms which suggested vanadium pentoxide incorporated in the pores of carbon cryogels. The nanocomposites showed much improved discharge capacity and better cyclic stability as compared to hydrous vanadium pentoxide films deposited on platinum foil. The discharge capacity of the nanocomposites reached 280 mAh/g based on the mass of the vandium pentoxide at a current density of 100mA/g and it possessed good cycle stability at different discharge rate. The results demonstrated that electrochemical performances, such as specific discharge capacitance and reversibility of the composite electrode, could be greatly enhanced by the introduction of carbon cryogels (CCs) scaffold with three-dimensionally interconnected porous structure in which V2O5•nH2O homogeneously dispersed.

  17. 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.

  18. Melting relations of hydrous and dry mantle compositions and the genesis of komatiites

    NASA Astrophysics Data System (ADS)

    Asahara, Y.; Ohtani, E.; Suzuki, A.

    The hydrous phase relations of primitive upper mantle model compositions in the CaO-MgO-Al2O3-SiO2-H2O system with 1, 2 and 5 wt.% H2O have been investigated with a multianvil high pressure apparatus at 6.5 GPa and temperatures from 1550°C to 2050°C. Liquidus temperatures decrease by about 100°C and the temperature interval to produce about 60% partial melting reduces to less than 50°C in the 1-2 wt.% H2O-bearing systems. At an H2O content of about 5 wt.%, garnet is the first dissolved phase and the stability field of orthopyroxene expands. Aluminum undepleted komatiite magmas can be formed by melting at 200 km depth in a hydrous mantle at significantly lower temperatures than under dry conditions. Thus, komatiite magmas cannot constrain temperatures in the Archean mantle. In addition, cratonic peridotites may have formed as residues of partial melting under various H2O contents.

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

    PubMed

    Matsukage, Kyoko N; Jing, Zhicheng; Karato, Shun-ichiro

    2005-11-24

    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 approximately 410 km 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.

  20. 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.

  1. 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.

  2. Chemical characterization of organic carbon dissolved in natural waters using inorganic adsorbents.

    PubMed

    Sugiyama, Y; Kumagai, T

    2001-01-01

    Dissolved organic carbon (DOC) in water samples from Lake Biwa was chemically characterized by two inorganic adsorbents with completely different surface characteristics. The two adsorbents were HIO (hydrous iron oxide) and SG (silica gel). Solutions of reference standard materials were analyzed concerning their adsorption behavior to HIO and SG for bovine serum albumin (BSA), fulvic acid extracted from the bottom sediments of Lake Biwa, phthalic acid, and starch. The adsorption of DOC to HIO was mainly controlled by ligand exchange and electrostatic interaction; that of SG was by electrostatic interaction. It was found that in a weak acid solution of around pH 5, BSA adsorbs to both HIO and SG, but that fulvic acid, phthalic acid and starch only show adsorption to HIO. Using these characteristics, DOC samples in natural water samples were characterized into pro-DOC, which adsorbs to both HIO and SG at pH 5, and car-DOC, which only adsorbs to HIO at pH 5. The DOC samples in Lake Biwa on October 7, 1997, at sampling sites Nb-2 and Nb-5 (south basin of Lake Biwa, the depths were about 2 and 4 m), and Ie-1 (north basin of Lake Biwa, the depth was about 75 m) were characterized. The pro-DOC has different values, depending on their sampling sites and depths, and had the maximum value of 0.42 mg C l(-1) at the surface water of Ie-1, and had the lowest values at middle to deeper water depths (0.18-0.27 mg C l(-1)). The car-DOC showed a relatively stable value at Ie-1 regardless of the depth (0.63-0.83 mg C l(-1)), and the maximum value was observed in Nb-2 and Nb-5 (1.2 and 1.3 mg C l(-1)). The ratios between car-DOC and pro-DOC concentrations were 0.2-0.5, and had different values for different sampling sites and depths. The ratios were significantly different for surface water samples where the biological activities are high and for bottom water samples where decomposition predominates.

  3. The Origin of Hydrous Minerals in Peridotite Mylonites from an Oceanic Transform Fault

    NASA Astrophysics Data System (ADS)

    Deems, N. J.; Warren, J. M.; McCubbin, F. M.; Wolfson-Schwehr, M.

    2014-12-01

    Previous studies of oceanic transform faults have assumed that fluid circulation ends when the transition from brittle failure to plastic flow occurs. However, we have identified significant amounts of hydrous minerals in peridotite mylonites from St. Paul's Rocks, a small set of islets on the St. Paul Transform Fault on the Mid-Atlantic Ridge. These rocks, which are highly deformed, are interpreted as having originated within the brittle-ductile transition zone. Our analyses show that the peridotites contain syn-deformational amphibole (12% on average) and minor phlogopite. In addition, the mylonites contain cm-scale veins of gabbro that are semi-parallel to foliation, which have been altered to amphibole, sodalite, and scapolite. Microprobe analysis indicates that the amphibole is pargasite, which is relatively rich in Na and Cl and requires temperatures >~700°C to form. In addition, sodalite and scapolite contain Na and Cl as essential elements. Initial stable isotope analysis indicates that δD of the pargasite lies between mantle δD (~70‰) and seawater (0‰). Based on our observations, we suggest that melt was introduced into the system either prior to or during deformation. In addition, we propose that either i) the melt was volatile-rich, providing the necessary water to form hydrous phases; or ii) seawater penetrated into the brittle-ductile transition zone by microfracturing, thus providing the necessary water, Na, and Cl to form the phases observed. While the 600°C isotherm is traditionally considered the limit of brittle deformation, this second hypothesis would suggest that seawater can penetrate to greater depths, in agreement with recent seismicity observations from an East Pacific Rise transform fault (McGuire et al., 2012). With additional stable isotope analysis and thermodynamic modeling, we plan to further constrain the source of melt/fluid at St. Paul's Rocks and thus improve constraints on OTF processes. If seawater is the origin of syn

  4. 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

  5. Plasticity of the dense hydrous magnesium silicate phase A at subduction zones conditions

    NASA Astrophysics Data System (ADS)

    Gouriet, K.; Hilairet, N.; Amiguet, E.; Bolfan-Casanova, N.; Wang, Y.; Reynard, B.; Cordier, P.

    2015-11-01

    The plasticity of the dense hydrous magnesium silicate (DHMS) phase A, a key hydrous mineral within cold subduction zones, was investigated by two complementary approaches: high-pressure deformation experiments and computational methods. The deformation experiments were carried out at 11 GPa, 400 and 580 °C, with in situ measurements of stress, strain and lattice preferred orientations (LPO). Based on viscoplastic self-consistent modeling (VPSC) of the observed LPO, the deformation mechanisms at 580 °C are consistent with glide on the (0 0 0 1) basal and (0 1 1 bar 0) prismatic planes. At 400 °C the deformation mechanisms involve glide on (2 bar 1 1 0) prismatic, (0 0 0 1) basal and { 1 1 2 bar 1 } pyramidal planes. Both give flow stresses of 2.5-3 GPa at strain rates of 2-4 × 10-5 s-1. We use the Peierls-Nabarro-Galerkin (PNG) approach, relying on first-principles calculations of generalized stacking fault (γ-surface), and model the core structure of potential dislocations in basal and prismatic planes. The computations show multiple dissociations of the 1/3 [ 2 1 bar 1 bar 0 ] and [ 0 1 1 bar 0 ] dislocations ( and dislocations) in the basal plane, which is compatible with the ubiquity of basal slip in the experiments. The γ-surface calculations also suggest 1/3 [ 2 1 bar 1 bar 3 ] and [ 0 1 bar 1 1 ] dislocations ( or directions) in prismatic and pyramidal planes, which is also consistent with the experimental data. Phase A has a higher flow strength than olivine. When forming at depths from the dehydration of weak and highly anisotropic hydrated ultramafic rocks, phase A may not maintain the mechanical softening antigorite can provide. The seismic properties calculated for moderately deformed aggregates suggest that S-wave seismic anisotropy of phase A-bearing rocks is lower than hydrous subduction zone lithologies such as serpentinites and blueschists.

  6. Geochemical changes and fracture development in Woodford Shale cores following hydrous pyrolysis under uniaxial confinement

    USGS Publications Warehouse

    Birdwell, Justin E.; Lewan, Michael D.; Miller, Michael; Baez, Luis; Beeney, Ken; Sonnenberg, Steve

    2013-01-01

    A uniaxial confinement clamp was used on Woodford Shale cores in hydrous pyrolysis experiments to study fracture development during thermal maturation. The clamp simulates overburden in that it prevents cores from expanding perpendicular to bedding fabric during the volume-increasing reactions associated with petroleum generation. Cores were cut from a slab of immature Woodford Shale and subjected to hydrous pyrolysis under confinement at 300, 330, and 365 °C for 72 hours to induce thermal maturities ranging from early bitumen to maximum expelled-oil generation. Two additional cores were used as experimental controls: (1) a confined core was saturated with water by heating it to 100 °C under hydrous pyrolysis conditions for 72 hours to use for characterization of the original rock, and (2) an unconfined core was heated at 365 °C for 72 hours to evaluate the effects of confinement on petroleum generation and expulsion. X-ray computed tomography (X-CT) imaging and other analyses identified five distinct beds within the cored interval. Using a tentative classification system, beds 1, 2, and 3 are described as dolomitic marlstone (DM) with total organic carbon (TOC) contents of 7.7, 5.8, and 7.7 wt. %, respectively; bed 4 is a cherty quartzose claystone (CQC) with TOC content of 5.5 wt. %; and bed 5 is a quartzose claystone with TOC content of 10.9 wt. %. Bed samples all had similar Rock-Eval hydrogen indices (600 ± 46 mg S2/g-TOC) and Tmax values (433 ± 2 °C), demonstrating organic matter uniformity and low thermal maturity. The X-CT scan of the core heated to 100 °C showed preexisting fractures that were nearly perpendicular to the bedding fabric primarily in the low-TOC DM bed 2 and CQC bed 4. Heating led to enhancement of preexisting fractures in the confined cores with the greatest enhancement occurring in CQC bed 4. The fractures increased in size and intensity with temperature. This is attributed to the internal pressure generated by volume

  7. 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.

  8. Sealed Lithium Inorganic Battery

    DTIC Science & Technology

    1976-08-01

    MuWrn , 1,ad iw..am m4 IdM.D to We"L406W) Inorganic Electrolyte lattery Carbon Cathode Evaluation Thionyl Chloride Gas Generation Lithium C ell sign...hardware surface to carry the reductIon of thionyl chloride when in contact with lithium (self discharge) and the corro,’ion of hardware materials... Lithium - Aluminum Chloride 10) AOSTSAC? (Cmawl/e o ade H .m.eewr W MWO, AV 600 nwe w) Stdies were continued of the effects of hardware materials on the

  9. 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)

  10. 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.

  11. Lithosphere thinning induced by slab penetration into a hydrous mantle transition zone

    NASA Astrophysics Data System (ADS)

    Wang, Zhensheng; Kusky, Timothy M.; Capitanio, Fabio A.

    2016-11-01

    Water plays an important role in deformation and partial melting of Earth's mantle. The mantle transition zone (MTZ) is a deep reservoir of bound water from subducting slabs. When this reservoir is perturbed by subducting slabs, water is released, impacting the rheology and dynamics of the mantle. We model the role of released water from the MTZ in lithospheric destruction, deformation and deep-source magmatism. Comparing the model results from the North China Craton, we infer that the first peak period of magmatism during craton destruction and lithospheric removal (135-115 Ma) resulted from the subducting Izanagi plate perturbing the strongly hydrous MTZ, whereas the second peak period of magmatism (80 Ma-Cenozoic) is related to extension and asthenospheric partial melting caused by Pacific slab rollback.

  12. 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??.

  13. 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.

  14. 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.

  15. 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?

  16. Stability of Hydrous Phase H MgSiO2(OH)2 Under the Lower Mantle Conditions

    NASA Astrophysics Data System (ADS)

    Ohtani, E.; Amaike, Y.; Kamada, S.; Sakamaki, T.; Hirao, N.

    2014-12-01

    Recent ab-initio calculation [1] and high pressure experiment [2] reported existence of a new high pressure hydrous phase, phase H with a composition of MgSiO2(OH)2. This phase has a structure similar to that of phase δ, AlOOH [3]. Here we report the stability field of this high pressure hydrous phase, phase H, and its implications for water transport into the deep lower mantle. We conducted in situ X-ray diffraction studies at high pressure and temperature on the stability field of hydous phase H, MgSiO2(OH)2. The high pressure and temperature were generated by using X-ray synchrotron radiation combined with the double-sided laser heating diamond anvil cell. We observed existence of hydrous phase H in the pressure range around 50 GPa, and it is stable up to 60 GPa and below 1610 K. The present results together with the previous works [1, 2, 3] indicate that the pure phase H MgSiO2(OH)2 has a very narrow stability field in a pressure range from 35 to 60 GPa, in the upper part of the lower mantle. The stability field expands significantly towards higher pressure and temperature by dissolution of hydous AlOOH component [4]. The hydrous phase H-phase δ solid solution (aluminous phase H), (MgSi,Al2)O2(OH)2, is potentially the most important hydrous phase under the deep lower mantle conditions. References: [1] Tsuchiya, J., 2013. Geophys. Res. Lett., 20, 4579-4573. [2] Nishi, M. et al., 2014. Nature Geoscience 7, 224-227. [3] Suzuki, A. et al., 2000. Phys. Chem. Miner.27, 689-693. [4] Ohira, I. et al., 2014. Earth Planet. Sci. Lett., 2014, in press.

  17. 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.

  18. Fabrication and characterization of materials and structures for hybrid organic-inorganic photonics

    NASA Astrophysics Data System (ADS)

    Haško, Daniel; Chovan, Jozef; Uherek, František

    2017-03-01

    Hybrid organic-inorganic integrated photonics integrate the organic material, as a part of active layer, with inorganic structure, and it is the organic component that extends the functionalities as compared to inorganic photonics. This paper presents the results of fabrication and characterization of inorganic and organic layers, as well as of hybrid organic-inorganic structures. Inorganic oxide and nitride materials and structures were grown using plasma enhanced chemical vapor deposition. As a substrate for tested organic layers and for preparation of multilayer structures, commercially available SiO2 created by thermal oxidation on Si was used. The hybrid organic-inorganic structures were prepared by spin coating of organic materials on SiO2/Si inorganic structures. As the basic photonics devices, the testing strip inorganic and organic waveguides were fabricated using reactive ion etching. The shape of fabricated testing waveguides was trapezoidal and etched structures were able to guide the radiation. The presented technology enabled to prepare hybrid organic-inorganic structures of comparable dimensions and shape. The fabricated waveguides dimensions and shape will be used for optimisation and design of new lithographic mask to prepare photonic components with required characteristics.

  19. 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.

  20. Miniature asymmetric ultracapacitor of patterned carbon nanotubes and hydrous ruthenium dioxide.

    PubMed

    Chen, Chun-Hung; Tsai, Dah-Shyang; Chung, Wen-Hung; Chiou, Yi-Deng; Lee, Kuei-Yi; Huang, Ying-Sheng

    2012-12-07

    A symmetric ultracapacitor CNT_CNT and an asymmetric ultracapacitor CNT_hRuO(2) of mini size have been prepared with patterned carbon nanotubes (CNT) and hydrous ruthenium dioxide. Galvanostatic charge/discharge results indicate that CNT_hRuO(2) is the superior one in both power and energy densities. In a potential window 2.0 V, the CNT_hRuO(2) cell displays an energy density of 24.0 W h kg(-1) at a power density of 22.9 kW kg(-1). Its power density can be raised to 41.1 kW kg(-1) at the expense of the energy density, which drops to 6.8 W h kg(-1). On the other hand, CNT_CNT performs at a lower level, delivering 5.2 W h kg(-1) at 5.5 kW kg(-1). The favorable charge/discharge performance of CNT_hRuO(2) is attributed to hydrous RuO(2), whose pseudocapacitance drives the other electrode of the vertical CNT array to work harder and makes more use of its double-layer capacitance. The analysis of individual electrode capacitance indicates that the high capacitance of hRuO(2) also causes a disproportion in voltage partition, which restricts the low limit of cycling current in an extended potential window. On energy cycling, CNT_hRuO(2) demonstrates sufficient stability in 10,000 cycles, after an initial 13% drop in capacitance.

  1. Experimental Investigation of Irradiation-driven Hydrogen Isotope Fractionation in Analogs of Protoplanetary Hydrous Silicate Dust

    NASA Astrophysics Data System (ADS)

    Roskosz, Mathieu; Laurent, Boris; Leroux, Hugues; Remusat, Laurent

    2016-11-01

    The origin of hydrogen in chondritic components is poorly understood. Their isotopic composition is heavier than the solar nebula gas. In addition, in most meteorites, hydrous silicates are found to be lighter than the coexisting organic matter. Ionizing irradiation recently emerged as an efficient hydrogen fractionating process in organics, but its effect on H-bearing silicates remains essentially unknown. We report the evolution of the D/H of hydrous silicates experimentally irradiated by electrons. Thin films of amorphous silica, amorphous “serpentine,” and pellets of crystalline muscovite were irradiated at 4 and 30 keV. For all samples, irradiation leads to a large hydrogen loss correlated with a moderate deuterium enrichment of the solid residue. The entire data set can be described by a Rayleigh distillation. The calculated fractionation factor is consistent with a kinetically controlled fractionation during the loss of hydrogen. Furthermore, for a given ionizing condition, the deuteration of the silicate residues is much lower than the deuteration measured on irradiated organic macromolecules. These results provide firm evidence of the limitations of ionizing irradiation as a driving mechanism for D-enrichment of silicate materials. The isotopic composition of the silicate dust cannot rise from a protosolar to a chondritic signature during solar irradiations. More importantly, these results imply that irradiation of the disk naturally induces a strong decoupling of the isotopic signatures of coexisting organics and silicates. This decoupling is consistent with the systematic difference observed between the heavy organic matter and the lighter water typically associated with minerals in the matrix of most carbonaceous chondrites.

  2. Crystal structure, thermal expansivity, and elasticity of OH-chondrodite: Trends among dense hydrous magnesium silicates

    DOE PAGES

    Ye, Yu; Jacobsen, Steven D.; Mao, Zhu; ...

    2015-04-01

    Here, we report the structure and thermoelastic properties of OH-chondrodite. The sample was synthesized at 12 GPa and 1523 K, coexisting with hydroxyl-clinohumite and hydrous olivine. The Fe content Fe/(Fe+Mg) is 1.1 mol%, and the monoclinic unit-cell parameters are: a = 4.7459(2) Å, b = 10.3480(7) Å, c = 7.9002(6) Å, α = 108.702(7)°, and V = 367.50(4) Å3. At ambient conditions the crystal structure was refined in space group P21/b from 1915 unique reflection intensities measured by single-crystal x-ray diffraction. The volume thermal expansion coefficient was measured between 150 and 800 K, resulting in αV = 2.8(5)×10-9(K-2) × Tmore » + 40.9(7) × 10-6(K-1) – 0.81(3)(K)/T2, with an average value of 38.0(9)×10-6 K-1. Brillouin spectroscopy was used to measure a set of acoustic velocities from which all thirteen components (Cij) of the elastic tensor were determined. The Voigt-Reuss-Hill average of the moduli yield for the adiabatic bulk modulus, KS0 = 117.9(12) GPa, and for shear modulus, G0 = 70.1(5) GPa. The Reuss bound on the isothermal bulk modulus (KT0) is 114.2(14) GPa. From the measured thermodynamic properties, the Grüneisen parameter (γ) is calculated to be 1.66(4). Fitting previous static compression data using our independently measured bulk modulus (isothermal Reuss bound) as a fixed parameter, we refined the first pressure derivative of the bulk modulus, KT’ = 5.5(1). Systematic trends between H2O content and physical properties are evaluated among dense hydrous magnesium silicate (DHMS) phases along the forsterite-brucite join.« less

  3. Sound velocities and elastic constants of iron-bearing hydrous ringwoodite

    NASA Astrophysics Data System (ADS)

    Jacobsen, Steven D.; Smyth, Joseph R.; Spetzler, Hartmut; Holl, Christopher M.; Frost, Daniel J.

    2004-06-01

    The sound velocities and single-crystal elastic constants of Fo 89 hydrous ringwoodite (γ-Mg 1.7Fe 0.22H 0.16SiO 4) containing ˜10,000 ppm by weight (1 wt.%) H 2O have been determined from seven separate pure-mode travel-time measurements using gigahertz ultrasonic interferometry. The experiments feature a new Yttrium-Aluminum-Garnet (YAG) P-to-S conversion shear buffer rod (BR), capable of producing pure ultrasonic shear waves with known polarization in the region of 0.5-2.0 GHz. To our knowledge they are the first such single-crystal ultrasonic measurements on a high-pressure phase recovered from the multi-anvil press. The cubic single-crystal elastic constants of hydrous Fo 89 ringwoodite at ambient conditions are (in GPa): c11=298±13, c44=112±6, and c12=115±6. Hydration of Fo ˜90 ringwoodite to 1 wt.% H 2O reduces the adiabatic bulk ( K0S=176±7 GPa) and shear ( G=103±5 GPa) moduli by about 6 and 13%, roughly equivalent to raising the temperature at room pressure by 600 and 1000 °C, respectively. Assuming a linear trend with hydration, we calculate that P- and S-wave velocities are reduced by about 40 m/s for every 1000 ppm weight (0.1 wt.%) H 2O added to Fo ˜90 ringwoodite. P- and S-wave velocities of the lower transition zone in PREM are consistent with a hydrated ringwoodite-rich composition.

  4. Synergistic influence of inorganic oxides (ZrO2 and SiO2) with N2H4 to protect composite coatings obtained via plasma electrolyte oxidation on Mg alloy.

    PubMed

    Zoubi, Wail Al; Kamil, Muhammad Prisla; Ko, Young Gun

    2017-01-18

    Different electrochemical approaches were proposed in this study to introduce nanoparticles to the coating layers, aiming at their in situ incorporation into the coating layers fabricated via plasma electrolytic oxidation (PEO). The addition of nanoparticles to the coating layers provided an electrochemical pathway to generate the functionalized coatings with a wide range of compositions and constituent phases as well giving the appearance of sealing the pores. In this study, the microstructure, chemical composition, and electrochemical response of the composite coating formed via one-stage PEO were compared with those obtained by means of structural modification of PEO coatings together with either impregnation or pre-deposition. For the combination of PEO and pre-deposition, the coating layer demonstrated less porous and better corrosion performance in the conditions used in this study, which were attributed to the denser and/or thicker layer resulting after incorporating the nanoparticles, such as SiO2 and ZrO2. In these methods, the nanoparticles were detected mainly not only near the coating surface, but also within the micro-defects inside the coating layers. Accordingly, the electrochemical analysis based on potentiodynamic polarization tests in 3.5 wt% NaCl solution clearly showed that the corrosion resistance of Mg alloy would be enhanced significantly due to the incorporation of SiO2 and ZrO2 or ZrO2 nanoparticles.

  5. Melting relations of hydrous pyrolite in CaO-MgO-Al2O3-SiO2-H2O System at the transition zone pressures

    NASA Astrophysics Data System (ADS)

    Litasov, Konstantin; Ohtani, Eiji; Taniguchi, Hiromitsu

    Phase relations and melt compositions in CaO-MgO-Al2O3-SiO2-pyrolite under hydrous (+2% of H2O) and anhydrous conditions have been determined at 13-20 GPa and 1600-2220°C. Liquidus and solidus temperatures for the hydrous system are about 50-100°C and 180-240°C lower than those for the dry system, respectively. Majorite is a liquidus phase of the hydrous pyrolite from 13 to 20 GPa. Olivine is a liquidus phase at 13 GPa and both periclase and majorite are the liquidus phases at 20 GPa in the dry pyrolite. We observed expansion of the stability field of anhydrous phase B in hydrous experiments. Compositions of partial melts at 13-20 GPa are generally similar in dry and hydrous systems, but hydrous melts contain more SiO2 at 13-17 GPa. The melts formed by low degree of melting have Al2O3-depleted and CaO-rich compositions. Trends of hydrous melt compositions are generally consistent with those of aluminum-depleted komatiite magmas.

  6. Inorganic-organic composite solid polymer electrolytes

    SciTech Connect

    Abraham, K.M.; Koch, V.R.; Blakley, T.J.

    2000-04-01

    Inorganic-organic composite solid polymer electrolytes (CSPEs) have been prepared from the poly(ethylene oxide) (PEO)-like electrolytes of the general formula polyvinylidene fluoride-hexafluoropropylene (PVdF-HFP)-PEO{sub n}-LiX and Li{sup +}-conducting ceramic powders. In the PEO-like electrolytes, PVdF-HFP is the copolymer of PVdF and HFP, PEO{sub n} is a nonvolatile oligomeric polyethylene oxide of {approximately}400 g/mol molecular weight, and LiX is lithium bis(trifluoroethylsulfonyl)imide. Two types of inorganic oxide ceramic powders were used: a highly Li{sup +}-conducting material of the composition 14 mol % Li{sub 2}O-9Al{sub 2}O{sub 3}-38TiO{sub 2}-39P{sub 2}O{sub 5}, and the poorly Li{sup +}-conducting Li-silicates Li{sub 4{minus}x}M{sub x}SiO{sub 4} where M is Ca or Mg and x is 0 or 0.05. The composite electrolytes can be prepared as thin membranes in which the Li{sup +} conductivity and good mechanical strength of the Li{sup +}-conducting inorganic ceramics are complemented by the structural flexibility and high conductivity of organic polymer electrolytes. Excellent electrochemical and thermal stabilities have been demonstrated for the electrolyte films. Li//composite electrolyte//LiCoO{sub 2} rechargeable cells have been fabricated and cycled at room temperature and 50 C.

  7. 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.

  8. Flexible inorganic nanowire light-emitting diode.

    PubMed

    Nadarajah, Athavan; Word, Robert C; Meiss, Jan; Könenkamp, Rolf

    2008-02-01

    We report a highly flexible light-emitting device in which inorganic nanowires are the optically active components. The single-crystalline ZnO nanowires are grown at 80 degrees C on flexible polymer-based indium-tin-oxide-coated substrates and subsequently encapsulated in a minimal-thickness, void-filling polystyrene film. A reflective top contact serving as the anode in the diode structure is provided by a strongly doped p-type polymer and an evaporated Au film. The emission through the polymer side of this arrangement covers most of the visual region. Electrical and optical properties as well as performance limitations of the device structure are discussed.

  9. 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.

  10. 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.

  11. PATHWAY OF INORGANIC ARSENIC METABOLISM

    EPA Science Inventory

    A remarkable aspect of the metabolism of inorganic arsenic in humans is its conversion to methylated metabolites. These metabolites account for most of the arsenic found in urine after exposure to inorganic arsenic. At least some of the adverse health effects attributed to inor...

  12. 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.

  13. 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

  14. 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.

  15. 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

  16. Emerging of Inorganic Hole Transporting Materials For Perovskite Solar Cells.

    PubMed

    Rajeswari, Ramireddy; Mrinalini, Madoori; Prasanthkumar, Seelam; Giribabu, Lingamallu

    2017-01-04

    Hole transporting material (HTM) is a significant component to achieve the high performance perovskite solar cells (PSCs). Over the years, inorganic, organic and hybrid (organic-inorganic) material based HTMs have been developed and investigated successfully. Today, perovskite solar cells achieved the efficiency of 22.1 % with with 2,2',7,7'-tetrakis(N,N-di-p-methoxyphenyl-amine) 9,9-spirobifluorene (spiro-OMeTAD) as HTM. Nevertheless, synthesis and cost of organic HTMs is a major challenging issue and therefore alternative materials are required. From the past few years, inorganic HTMs showed large improvement in power conversion efficiency (PCE) and stability. Recently CuOx reached the PCE of 19.0% with better stability. These developments affirms that inorganic HTMs are better alternativesto the organic HTMs for next generation PSCs. In this report, we mainly focussed on the recent advances of inorganic and hybrid HTMs for PSCs and highlighted the efficiency and stability of PSCs improved by changing metal oxides as HTMs. Consequently, we expect that energy levels of these inorganic HTMs matches very well with the valence band of perovskites and improved efficiency helps in future practical deployment of low cost PSCs.

  17. A comparison of organic and inorganic nitrates/nitrites.

    PubMed

    Omar, Sami A; Artime, Esther; Webb, Andrew J

    2012-05-15

    Although both organic and inorganic nitrates/nitrites mediate their principal effects via nitric oxide, there are many important differences. Inorganic nitrate and nitrite have simple ionic structures and are produced endogenously and are present in the diet, whereas their organic counterparts are far more complex, and, with the exception of ethyl nitrite, are all medicinally synthesised products. These chemical differences underlie the differences in pharmacokinetic properties allowing for different modalities of administration, particularly of organic nitrates, due to the differences in their bioavailability and metabolic profiles. Whilst the enterosalivary circulation is a key pathway for orally ingested inorganic nitrate, preventing an abrupt effect or toxic levels of nitrite and prolonging the effects, this is not used by organic nitrates. The pharmacodynamic differences are even greater; while organic nitrates have potent acute effects causing vasodilation, inorganic nitrite's effects are more subtle and dependent on certain conditions. However, in chronic use, organic nitrates are considerably limited by the development of tolerance and endothelial dysfunction, whereas inorganic nitrate/nitrite may compensate for diminished endothelial function, and tolerance has not been reported. Also, while inorganic nitrate/nitrite has important cytoprotective effects against ischaemia-reperfusion injury, continuous use of organic nitrates may increase injury. While there are concerns that inorganic nitrate/nitrite may induce carcinogenesis, direct evidence of this in humans is lacking. While organic nitrates may continue to dominate the therapeutic arena, this may well change with the increasing recognition of their limitations, and ongoing discovery of beneficial effects and specific advantages of inorganic nitrate/nitrite.

  18. 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

  19. 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

  20. Dynamics in Hydrous Silicates Studied by High Temperature High Pressure Quasielastic Neutron Scattering

    NASA Astrophysics Data System (ADS)

    Yang, F.; Meyer, A.; Unruh, T.

    2008-12-01

    Dissolved water in silicate melts plays an important role in many geological processes, especially in active volcanism. The knowledge of microscopic dynamics of the water species represents a key for the understanding of these processes and to predict macroscopic melt properties like viscosity. We study water dynamics in hydrous silicate melts employing quasielastic neutron scattering technique. Neutron scattering provides simultaneously information on the microscopic structure and dynamics of the sample. At the new time-of-flight spectrometer TOFTOF of FRM II a high energy resolution of about several tens μeVs can be obtained together with a large neutron flux as well as an excellent signal-to-noise ratio, which is ideal for such kind of investigation. In order to investigate the water dynamics in hydrous silicate melts at the temperatures relevant for volcanic processes, a pressure of about 150-200 MPa is needed at the mean time to prevent the degassing and foaming of the sample. A high temperature high pressure cell was constructed as sample environment with a relative large opening angle optimized for the tof-spectrometer. The cell provides a temperature range from RT up to 1500 K with a pressure up to 200 MPa at the sample position with an available sample volume of about 1 cm3, achieved by an internally heated NbZr autoclave. Applying the cell, we successfully performed quasielastic neutron scattering experiments on sodium trisilicate (Na2O·3SiO2), sodium aluminosilicate (Al2O3·Na2O·6SiO2, Albite: haplogranitic rock composition) and pure silica (SiO2) samples with 10 mol% water content in the temperature range from 850 K to 1250 K. Taking advantage of the large difference in neutron scattering cross-sections of H and D, a contrast variation via H2O/D2O substitution gives access to the pure incoherent proton dynamics. An unusual behaviour of the density correlation functions in hydrous sodium trisilicate melt has been observed. The proton dynamics is not

  1. Polyoxometalates: from inorganic chemistry to materials science.

    PubMed

    Casañ-Pastor, Nieves; Gómez-Romero, Pedro

    2004-05-01

    Polyoxometalates have been traditionally the subject of study of molecular inorganic chemistry. Yet, these polynuclear molecules, reminiscent of oxide clusters, present a wide range of structures and with them ideal frameworks for the deployment of a plethora of useful magnetic, electroionic, catalytic, bioactive and photochemical properties. With this in mind, a new trend towards the application of these remarkable species in materials science is beginning to develop. In this review we analyze this trend and discuss two main lines of thought for the application of polyoxometalates as materials. On the one hand, there is their use as clusters with inherently useful properties on themselves, a line which has produced fundamental studies of their magnetic, electronic or photoelectrochemical properties and has shown these clusters as models for quantum-sized oxides. On the other hand, the encapsulation or integration of polyoxometalates into organic, polymeric or inorganic matrices or substrates opens a whole new field within the area of hybrid materials for harnessing the multifunctional properties of these versatile species in a wide variety of applications, ranging from catalysis to energy storage to biomedicine.

  2. Zircon record of fractionation, hydrous partial melting and thermal gradients at different depths in oceanic crust (ODP Site 735B, South-West Indian Ocean)

    NASA Astrophysics Data System (ADS)

    Pietranik, A.; Storey, C.; Koepke, J.; Lasalle, S.

    2017-03-01

    Felsic veins (plagiogranites) are distributed throughout the whole oceanic crust section and offer insight into late-magmatic/high temperature hydrothermal processes within the oceanic crust. Despite constituting only 0.5% of the oceanic crust section drilled in IODP Site 735B, they carry a significant budget of incompatible elements, which they redistribute within the crust. Such melts are saturated in accessory minerals, such as zircon, titanite and apatite, and often zircon is the only remaining phase that preserves magmatic composition and records processes of felsic melt formation and evolution. In this study, we analysed zircon from four depths in IODP Site 735B; they come from the oxide gabbro (depth approximately 250 m below sea floor) and plagiogranite (depths c. 500, 860, 940 m below sea floor). All zircons have similar ɛHf composition of c. 15 units indicating an isotopically homogenous source for the mafic magmas forming IODP Site 735B gabbro. Zircons from oxide gabbro are scarce and variable in composition consistent with their crystallization from melts formed by both fractionation of mafic magmas and hydrous remelting of gabbro cumulate. On the other hand, zircon from plagiogranite is abundant and each sample is characterized by compositional trends consistent with crystallization of zircon in an evolving melt. However, the trends are different between the plagiogranite at 500 m bsf and the deeper sections, which are interpreted as the record of plagiogranite formation by two processes: remelting of gabbro cumulate at 500 m bsf and fractionation at deeper sections. Zircon from both oxide gabbro and plagiogranite has δ18O from 3.5 to 6.0‰. Values of δ18O are best explained by redistribution of δ18O in a thermal gradient and not by remelting of hydrothermally altered crust. Tentatively, it is suggested that fractionation could be an older episode contemporaneous with gabbro crystallization and remelting could be a younger one, triggered by

  3. XPS determination of Mn oxidation states in Mn (hydr)oxides

    SciTech Connect

    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 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 common layered structure that occurs readily in Nature 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 widths of each oxidation state, composed of a packet of correlated component peaks, were allowed vary. whereas 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, whereas Mn2p3/2 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 Mn2p. Consequently, fitting the Mn3p and Mn3s lines yields robust quantification of oxidation states over a range of hydrous Mn oxide polytypes and compositions. In contrast, a common method for determining oxidation states that utilizes the multiplet splitting of the Mn3s line is not appropriate for birnessites.

  4. The origin of low velocity layers in subduction zones: elasticity of hydrous phases at high pressures and temperatures

    NASA Astrophysics Data System (ADS)

    Mookherjee, M.; Chantel, J.; Frost, D. J.

    2012-12-01

    A 5-10 km thick low velocity layer (LVL) at the top of the subducting slab has been seismically detected in many subduction zone settings. The LVL may persist up to a depth of 250 km. The shear wave velocity of the LVL could be 10 % slower than the surrounding mantle. Based on thermal profile of the subducting slabs it is hard to relate the LVL with partial melting or pore fluids. We have undertaken experimental and theoretical studies to constrain the pressure and temperature dependence of elasticity of eclogitic rocks formed from hydrated oceanic crust. In particular, we focus on hydrous phases such as lawsonite [CaAl2Si2O7(OH)2.H2O]. Our study shows that lawsonite has unusual shear modulus at high pressure and temperatures relevant at 250 km depths. Formation of hydrous phases such as lawsonite at the expense of garnet additionally lowers the seismic velocities.

  5. Hydrous solidus of CMAS-pyrolite and melting of mantle plumes at the bottom of the upper mantle

    NASA Astrophysics Data System (ADS)

    Litasov, Konstantin; Ohtani, Eiji

    2003-11-01

    We showed in previous experiments that the melting temperature of hydrous pyrolite, at the transition boundary between wadsleyite and olivine, is abruptly reduced by the presence of 2 wt.% H2O. In this paper we determine the apparent solidus for CaO-MgO-Al2O3-SiO2-pyrolite with lower and geologically more reasonable H2O contents (0.5 wt.%). Phase relations and melt compositions have been determined at pressures of 13.5-17.0 GPa and temperatures of 1600 to 2100°C. There was no abrupt decrease of solidus temperature along the phase boundary between olivine and wadsleyite in pyrolite with 0.5 wt.% H2O. However significant gradual decrease of the solidus temperature at pressures below 15-16 GPa still supports previous models for a hydrous origin of some ancient komatiites by dehydration melting of rising wet plumes at pressures of 4-10 GPa.

  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. Electrical conductivity of hydrous mantle minerals, with implications for the conductivity structure of the mantle transition zone

    NASA Astrophysics Data System (ADS)

    Guo, X.; Yoshino, T.

    2011-12-01

    Water plays an important role in the electrical conductivity of the mantle transition zone. For example, high conductivity values were observed in the mantle transition zone beneath the Philippine Sea. Recent laboratory electrical conductivity measurements focused on wadsleyite and ringwoodite. However, it is difficult to explain high conductivity in the transition zone, although proton conduction in these minerals can enhance the conductivity. Most of water was transported into the mantle by hydrous minerals with descending slab. Some dense hydrous magnesium silicates (DHMS) can be stable in the descending slab (e.g. super hydrous phase B and phase D), which are expected to exhibit high conductivity due to the high water content in the crystal structure. However, the contribution of DHMS to the electrical conductivity has not been investigated. Here we report the electrical conductivities of brucite, phase A and super hydrous phase B under high pressure condition and the pressure effect on the conductivity of brucite. The electrical conductivity of brucite, phase A and super hydrous phase B (suB) ploycrystals, were measured by means of impedance spectroscopy in the frequency range 10-2-106 Hz at pressures of 3 GPa, 10 GPa and 18 GPa, respectively, and in the temperature range of 500-775 K. The increase of electrical conductivity with temperature follows the Arrhenian formula: σ =σ0exp(-ΔH/kT). The pre-exponential factors and activation enthalpies of brucite, phase A and suB yield values of 149.7 S/m and 0.90 eV, 4.88 S/m and 0.74 eV, 292 S/m and 0.83 eV, respectively. The electrical conductivities of brucite (water content of 30.9 wt.%) at 3 GPa was about one order lower of magnitude compared with those of suB (water content of 5.8 wt.%) at 18 GPa, and slightly higher than those of phase A at 10 GPa (water content of 11.9 wt.%) in the measured temperature range. For brucite, effect of pressure on the electrical conductivity was also investigated in the pressure

  8. Origin of primitive arc basaltic andesites by shallow, hydrous mantle melting

    NASA Astrophysics Data System (ADS)

    Andrews, A.; Grove, T. L.

    2012-12-01

    Primitive, high-magnesium basaltic andesites and andesites (51-58 wt. % SiO2, 9-11 wt. % MgO) provide a unique window into hydrous melting processes in the shallow mantle wedge. While it is thought that melting the hydrous mantle at shallow depths produces these primitive melts in equilibrium with a harzburgitic (olivine + orthopyroxene) residue (Wood and Turner, 2009), the exact conditions under which these melts form remain elusive. We have conducted a suite of experiments on a synthetic mix of primitive upper mantle composition (Hart and Zindler, 1986) at varying temperatures, pressures, and water contents in pursuit of a systematic understanding of the conditions that allow for the generation of these unique magmas. The data obtained thus far show a strong correlation between decreasing temperature and increasing silica content. Using this relationship, as well as constraints from high-magnesium basaltic andesites produced at 1.2 GPa, 1275-1363°C, and 1-2 wt. % H2O, additional isobaric experiments are underway at lower temperatures and higher water contents to determine whether the correlation continues and more silica-rich compositions are produced. For each experiment in our data set, the activity coefficient of SiO2 in the melt (γ_SiO2^melt) shows a positive deviation from ideality. As the water content is increased, ln γ_SiO2^melt moves farther from ideal conditions, suggesting that only a non-ideal solution model can adequately explain water's effect on the silica content of the melt produced in these experiments. Using this new experimental data set, we are able to explore the conditions that produce primitive, high magnesium basaltic andesites and andesites as well as increase our understanding of the thermodynamics behind these conditions and resulting melts. At this point, a primary melting origin seems to require a combination of very shallow depths (P<1.2 GPa) and very high H2O contents (>6 wt. % H2O).

  9. Crystal structure, thermal expansivity, and elasticity of OH-chondrodite: Trends among dense hydrous magnesium silicates

    SciTech Connect

    Ye, Yu; Jacobsen, Steven D.; Mao, Zhu; Duffy, Thomas S.; Hirner, Sarah M.; Smyth, Joseph R.

    2015-04-01

    Here, we report the structure and thermoelastic properties of OH-chondrodite. The sample was synthesized at 12 GPa and 1523 K, coexisting with hydroxyl-clinohumite and hydrous olivine. The Fe content Fe/(Fe+Mg) is 1.1 mol%, and the monoclinic unit-cell parameters are: a = 4.7459(2) Å, b = 10.3480(7) Å, c = 7.9002(6) Å, α = 108.702(7)°, and V = 367.50(4) Å3. At ambient conditions the crystal structure was refined in space group P21/b from 1915 unique reflection intensities measured by single-crystal x-ray diffraction. The volume thermal expansion coefficient was measured between 150 and 800 K, resulting in αV = 2.8(5)×10-9(K-2) × T + 40.9(7) × 10-6(K-1) – 0.81(3)(K)/T2, with an average value of 38.0(9)×10-6 K-1. Brillouin spectroscopy was used to measure a set of acoustic velocities from which all thirteen components (Cij) of the elastic tensor were determined. The Voigt-Reuss-Hill average of the moduli yield for the adiabatic bulk modulus, KS0 = 117.9(12) GPa, and for shear modulus, G0 = 70.1(5) GPa. The Reuss bound on the isothermal bulk modulus (KT0) is 114.2(14) GPa. From the measured thermodynamic properties, the Grüneisen parameter (γ) is calculated to be 1.66(4). Fitting previous static compression data using our independently measured bulk modulus (isothermal Reuss bound) as a fixed parameter, we refined the first pressure derivative of the bulk modulus, KT’ = 5.5(1). Systematic trends between H2O content and physical properties are evaluated among dense hydrous magnesium silicate (DHMS) phases along the forsterite-brucite join.

  10. Thermal-maturity limit for primary thermogenic-gas generation from humic coals as determined by hydrous pyrolysis

    USGS Publications Warehouse

    Lewan, Michael; Kotarba, M.J.

    2014-01-01

    Hydrous-pyrolysis experiments at 360°C (680°F) for 72 h were conducted on 53 humic coals representing ranks from lignite through anthracite to determine the upper maturity limit for hydrocarbon-gas generation from their kerogen and associated bitumen (i.e., primary gas generation). These experimental conditions are below those needed for oil cracking to ensure that generated gas was not derived from the decomposition of expelled oil generated from some of the coals (i.e., secondary gas generation). Experimental results showed that generation of hydrocarbon gas ends before a vitrinite reflectance of 2.0%. This reflectance is equivalent to Rock-Eval maximum-yield temperature and hydrogen indices (HIs) of 555°C (1031°F) and 35 mg/g total organic carbon (TOC), respectively. At these maturity levels, essentially no soluble bitumen is present in the coals before or after hydrous pyrolysis. The equivalent kerogen atomic H/C ratio is 0.50 at the primary gas-generation limit and indicates that no alkyl moieties are remaining to source hydrocarbon gases. The convergence of atomic H/C ratios of type-II and -I kerogen to this same value at a reflectance of indicates that the primary gas-generation limits for humic coal and type-III kerogen also apply to oil-prone kerogen. Although gas generation from source rocks does not exceed vitrinite reflectance values greater than , trapped hydrocarbon gases can remain stable at higher reflectance values. Distinguishing trapped gas from generated gas in hydrous-pyrolysis experiments is readily determined by of the hydrocarbon gases when a -depleted water is used in the experiments. Water serves as a source of hydrogen in hydrous pyrolysis and, as a result, the use of -depleted water is reflected in the generated gases but not pre-existing trapped gases.

  11. 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.

  12. 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.

  13. Asymmetric block copolymers for supramolecular templating of inorganic nanospace materials.

    PubMed

    Bastakoti, Bishnu Prasad; Li, Yunqi; Kimura, Tatsuo; Yamauchi, Yusuke

    2015-05-06

    This review focuses on polymeric micelles consisting of asymmetric block copolymers as designed templates for several inorganic nanospace materials with a wide variety of compositions. The presence of chemically distinct domains of asymmetric triblock and diblock copolymers provide self-assemblies with more diverse morphological and functional features than those constructed by EOn POm EOn type symmetric triblock copolymers, thereby affording well-designed nanospace materials. This strategy can produce unprecedented nanospace materials, which are very difficult to prepare through other conventional organic templating approaches. Here, the recent development on the synthesis of inorganic nanospace materials are mainly focused on, such as hollow spheres, tubes, and porous oxides, using asymmetric triblock copolymers.

  14. Biologically-synthesized inorganic nanomaterials

    NASA Astrophysics Data System (ADS)

    Kramer, Ryan M.; Stone, Morley O.; Naik, Rajesh R.

    2004-06-01

    A hallmark of biological systems is their ability to self-assemble. This self-assembly can occur on the molecular, macromolecular and mesoscale. In this work, we have chosen to exploit biology's ability to self-assemble by incorporating additional functionality within the final structure. Our research efforts have been directed at not only understanding how biological organisms control nucleation and growth of inorganic materials, but also how this activity can be controlled in vitro. In previous work, we have demonstrated how peptides can be selected from a combinatorial library that possesses catalytic activity with respect to inorganic nucleation and deposition. We have engineered some of these peptide sequences into self-assembling protein structures. The goal of the project was to create an organic/inorganic hybrid that retained the "memory" properties of the organic, but possessed the superior optical and electronic properties of the inorganic.

  15. Importance of hydrous pyrolysis studies in properly identifying source rocks of the Unita basin

    SciTech Connect

    Ruble, T.E.; Lewan, M.D.; Philp, R.P.

    1995-12-01

    The Uinta Basin in northeastern Utah historically has received considerable attention from petroleum geochemists; as a classic model of hydrocarbon generation from lacustrine source rocks. Previous work has focused primarily on the organic-rich Type-I algal kerogen contained in the Mahogany zone of the upper Green River Formation. Although recently published geochemical data suggest Mahogany zone source rocks are too immature to have generated the basin`s hydrocarbon reserves, this unit has been used as an analog for open lacustrine source rocks inferred to be buried more deeply. A series of hydrous pyrolysis experiments were conducted to examine this hypothesis. Source rocks included both the Mahogany zone and the basal Green River {open_quotes}black shale facies{close_quotes}. Compositional differences in the expelled pyrolysates suggest only the {open_quotes}black shale facies{close_quotes} is the source of the waxy crude oils produced in the Uinta Basin. Kinetic parameters derived from these experiments support such an interpretation and offer new insights for modeling hydrocarbon generation. These parameters have also been compared to previously reported values and those determined by Rock-Eval analysis.

  16. Removal of Pb(II) from aqueous solution by hydrous manganese dioxide: adsorption behavior and mechanism.

    PubMed

    Xu, Meng; Wang, Hongjie; Di, Lei; Qu, Dan; Zhai, Yujia; Wang, Yili

    2013-03-01

    Hydrous manganese dioxide (HMO) synthesized by redox of potassium permanganate and hydrogen peroxide was used as an adsorbent for Pb(II) removal. The specific surface area, pore volume and BJH pore diameter of the HMO were 79.31 m2/g, 0.07 cm3/g and 3.38 nm, respectively. The adsorption equilibrium at 298 K could be well described by the Langmuir isotherm equation with qmax value of 352.55 mg/g. The negative values of deltaG and the positive values of deltaH and deltaS indicated the adsorption process was spontaneous and endothermic. The pseudo second-order equation could best fit the adsorption data. The value of the calculated activation energy for Pb(II) adsorption onto the HMO was 38.23 kJ/mol. The uptake of Pb(II) by HMO was correlated with increasing surface hydroxyl group content and the main adsorbed speciation was PbOH+. The final chemical state of Pb(II) on the surface of HMO was similar to PbO. HMO was a promising candidate for Pb(II) removal from aqueous solution.

  17. Dissolution of tonalitic enclaves in ascending hydrous granitic magmas: An experimental study

    NASA Astrophysics Data System (ADS)

    García-Moreno, O.; Castro, A.; Corretgé, L. G.; El-Hmidi, H.

    2006-07-01

    Dissolution of natural mafic magmatic enclaves in a hydrous leucogranitic synthetic melt has been tested experimentally. Results suggest that the mechanism of enclave dissolution is a potential hybridization process in granitic systems. Experiments performed in decompression, simulating ascending magmas, show interesting results: from 10 kbar to 4 kbar, for a given temperature, enhanced dissolution of the tonalitic enclave into the melt has been observed, compared with experiments at constant pressure. Furthermore, the composition of the melt changed to higher CaO, FeO and MgO contents. Dissolution textures on relict crystals from the tonalitic enclave were monitored. These results have implications for the generation of peraluminous monzogranites and granodiorites and an example for the Cabeza de Araya (Cáceres, Spain) from the "serie mixta" of the Iberian Massif is given. The tonalitic enclaves that are partially dissolved may be early or coeval intrusions into the granite magma or even into the source migmatitic area. Many mineralogical, geochemical and isotopic features of monzogranites (e.g.: reverse zoning in plagioclase, low Sr isotopic ratios) are accounted for by this mechanism of enclave dissolution during ascent and emplacement.

  18. Hydrous upwelling across the mantle transition zone beneath the Afar Triple Junction

    NASA Astrophysics Data System (ADS)

    Thompson, D. A.; Kendall, J. M.; Hammond, J. O. S.; Stuart, G. W.; Helffrich, G. R.; Keir, D.; Ayele, A.; Goitom, B.

    2014-12-01

    The upwelling of material from the lower mantle to the base of the lithosphere is hypothesised as being a primary geodynamic process and the mechanisms that drive upwelling (e.g. thermal vs. compositional buoyancy) are key to our understanding of whole mantle convection. We address these issues with new seismic data from recent deployments located on the Afar Triple Junction. The detailed images of deep structure beneath this large igneous province illuminate features that give insights into the nature of upwelling from the deep mantle. A seismic low velocity layer directly above the mantle transition zone, interpreted as a stable melt layer, along with a prominent 520 km discontinuity suggest the presence of a hydrous upwelling. Coincident with these features is a tomographically determined low velocity feature within the mantle transition zone, and relatively uniform transition zone thickness associated with this implies little variation in temperature. This suggests that upwelling is driven by compositional as opposed to thermal buoyancy. The results are consistent with volatile rich, chemically distinct upwellings rising from a heterogenous lower mantle source within the African Superplume.

  19. 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.

  20. 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.

  1. First-principles calculation of H/D isotopic fractionation between hydrous minerals and water

    NASA Astrophysics Data System (ADS)

    Méheut, Merlin; Lazzeri, Michele; Balan, Etienne; Mauri, Francesco

    2010-07-01

    Hydrogen fractionation laws between selected hydrous minerals (brucite, kaolinite, lizardite, and gibbsite) and perfect water gas have been computed from first-principles quantum-mechanical calculations. The β-factor of each phase was calculated using the harmonic phonon dispersion curves obtained within density functional theory. All the fractionation laws show the same shape, with a minimum between 200 °C (brucite) and 500 °C (gibbsite). At low temperatures, the mineral/liquid water fractionation laws have been obtained using the experimental gas/liquid water fractionation laws. The resulting fractionation laws systematically overestimate measurements by 15‰ at low temperatures to 8‰ at ≈400 °C. Based on this general agreement, all calculated laws were empirically corrected with reference to brucite/water data. These considerations suggest that the experimental or natural calibrations by Xu and Zheng (1999) and Horita et al. (2002) (brucite/water), Gilg and Sheppard (1996) (kaolinite/water), Wenner and Taylor (1973) (lizardite/water), and in some extents Vitali et al. (2001) (gibbsite/water) are representative of equilibrium fractionations. Besides, internal isotopic fractionation of hydrogen between inner-surface and inner hydroxyl groups has been computed for kaolinite and lizardite. The obtained fractionation is large, of opposite sign for the two systems (respectively, -23‰ and +63‰ at 25 °C) and is linear in T-2. Internal fractionation of hydrogen in TO phyllosilicates might thus be used in geothermometry.

  2. 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.

  3. Polymer encapsulation of inorganic nanoparticles for biomedical applications.

    PubMed

    Ladj, Rachid; Bitar, Ahmad; Eissa, Mohamed M; Fessi, Hatem; Mugnier, Yannick; Le Dantec, Ronan; Elaissari, Abdelhamid

    2013-12-15

    Hybrid inorganic colloidal particles have attracted a great attention in the last years, and they have been largely used in various applications and more particularly in biomedical nanotechnology. Recently, they are used as carriers for biomolecules, and exploited for use in microsystems, microfluidics and in lab-on-a chip based bionanotechnology. Various kinds of hybrid particles can be listed starting from classical inorganic nanoparticles such as silica, gold, silver, iron oxide and those exhibiting intrinsic properties such as semiconducting nanoparticles (e.g. quantum dots). As a general tendency, to be conveniently used in biomedical applications, the encapsulation of the inorganic nanoparticles in a polymer matrix is incontestably needed. Consequently, various chemistry-based encapsulation processes have been developed and showed promising results as compared to the encapsulation using preformed polymers.

  4. 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.

  5. Natural Attenuation of Metals from Acid Drainage in Surface Waters: Effects of Organic Matter in the Association of Arsenic to Hydrous Al and Fe Oxyhydroxides and Their Particle Size Distribution

    NASA Astrophysics Data System (ADS)

    Arce, G. J.; Pasten, P.; Coquery, M.; Abarca, M. I.; Montecinos, M.

    2015-12-01

    The presence of toxic metals in watersheds affected by acid drainage (AD) imposes a challenge for sustainable supply of water for cities, agriculture and industry. The formation and settling of metal-rich HFO (hydrous ferric oxides) and HAO (hydrous aluminum oxides) is a relevant mechanism for the attenuation of dissolved metals from AD, particularly for arsenic. Organic matter is known to alter the chemical speciation and key physical properties like particle size distribution (PSD) and settling velocity of HFO and HAO particle suspensions. However, available experimental studies focus either on chemical or physical properties. We used a suite of analytical techniques to probe the effects of organic matter on particle suspensions formed in natural waters and in laboratory model systems. Dissolved organic matter was added at different concentrations (0, 0.1, 0.3, 0.6, 1 and 1.5 mg C/L) to synthetic AD before neutralization with alkaline solutions. PSD and average particle size were measured with laser scattering transmissometry (LISST), while organic matter was characterized by total organic carbon (TOC) and UV-VIS spectrometry. Larger concentrations of organic matter lead to the formation of particle suspensions with larger particle volume and size. When 1.5 mg C/L were added, the total particle volume concentration increased from 0.67 to 23.74 μL/L, while the mean particle size increased from 102 to 176 μm. These results suggests that organic matter influences the fate of metals from AD. Undergoing measurements include total and dissolved metal analyses with total reflection X-ray fluorescence (TXRF) and ICP-OES to confirm increased removal of dissolved arsenic. The results from this research are necessary to understand the processes governing natural attenuation of metal contamination in fluvial systems affected by AD and to serve as the basis for enhanced natural attenuation schemes. The authors acknowledge funding from Fondecyt 1130936.

  6. 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.

  7. Shock compression of silica gel as the analog experiments of hydrous comet and meteorite

    NASA Astrophysics Data System (ADS)

    Arasuna, Akane; Okuno, Masayuki; Mizukami, Tomoyuki; Chen, Liliang; Mashimo, Tsutomu; Arai, Shoji; Okudera, Hiroki

    2013-04-01

    The studies for structural changes of hydrous silica materials by shock compression are important to obtain the information for compression behaviors of comet and meteorite made of silicate material, ice and hydroxyl on the impact event. In this study, TEOS-derived synthetic silica gels for the analog material of hydrous amorphous silica minerals were compressed under shock pressures of 11, 13, 17, 21, 27, and 31 GPa using a single-stage propellant gun. All recovered samples have been investigated by XRD measurements, Raman and IR spectroscopies, in order to elucidate the shock compression behavior of silica gel. Pressure variation of first sharp diffraction peak (FSDP) positions of samples was estimated from measured XRD patterns. FSDP position of as-prepared sample was smaller than silica glass. It indicates that medium range structure of silica gel, i.e. ring structure of SiO4 tetrahedra, is smaller than that of silica glass. FSDP positions showed negative shift with increasing pressure and approached that of silica glass at 31 GPa. It suggests that medium range structure of silica gel approached to silica glass by shock compression. Raman spectrum of as-prepared sample showed an intense D1 band at 480 cm-1 and a broad band at around 450 cm-1. The former is attributed to the oxygen-breathing mode of the four-membered ring of SiO4 tetrahedra and the latter to the symmetrical Si-O-Si stretching mode. The presence of strong D1 band of as-prepared sample indicates that the sample might contain considerable amount of four-membered rings in the structure. Shocked sample showed that the broad band around 450 cm-1 became prominent above 21 GPa, whereas D1 band became much less intense. These indicate that medium range structure of shocked sample above 21 GPa approached to that of silica glass. Furthermore, IR spectrum of shocked silica gel at 21 GPa indicates that the center part of sample showed development of vitrification as compared with the extremity part of the

  8. A Silica/Fly Ash-Based Technology for Controlling Pyrite Oxidation

    SciTech Connect

    V. P. Evangelou

    1997-04-14

    The purpose of our studies during this past six-month period was to evaluate the surface properties of iron-oxide-silicate coatings. The specific objectives were (a) to evaluate the mechanisms and ability of hydrous ferric oxide (HFO) to adsorb silica (Si); (b) to evaluate the effects of Si on the bulk and surface properties of HFO; and (c) to evaluate the effect of Si on heavy-metal adsorption properties by iron-oxides.

  9. The thermodynamic scale of inorganic crystalline metastability.

    PubMed

    Sun, Wenhao; Dacek, Stephen T; Ong, Shyue Ping; Hautier, Geoffroy; Jain, Anubhav; Richards, William D; Gamst, Anthony C; Persson, Kristin A; Ceder, Gerbrand

    2016-11-01

    The space of metastable materials offers promising new design opportunities for next-generation technological materials, such as complex oxides, semiconductors, pharmaceuticals, steels, and beyond. Although metastable phases are ubiquitous in both nature and technology, only a heuristic understanding of their underlying thermodynamics exists. We report a large-scale data-mining study of the Materials Project, a high-throughput database of density functional theory-calculated energetics of Inorganic Crystal Structure Database structures, to explicitly quantify the thermodynamic scale of metastability for 29,902 observed inorganic crystalline phases. We reveal the influence of chemistry and composition on the accessible thermodynamic range of crystalline metastability for polymorphic and phase-separating compounds, yielding new physical insights that can guide the design of novel metastable materials. We further assert that not all low-energy metastable compounds can necessarily be synthesized, and propose a principle of 'remnant metastability'-that observable metastable crystalline phases are generally remnants of thermodynamic conditions where they were once the lowest free-energy phase.

  10. The thermodynamic scale of inorganic crystalline metastability

    PubMed Central

    Sun, Wenhao; Dacek, Stephen T.; Ong, Shyue Ping; Hautier, Geoffroy; Jain, Anubhav; Richards, William D.; Gamst, Anthony C.; Persson, Kristin A.; Ceder, Gerbrand

    2016-01-01

    The space of metastable materials offers promising new design opportunities for next-generation technological materials, such as complex oxides, semiconductors, pharmaceuticals, steels, and beyond. Although metastable phases are ubiquitous in both nature and technology, only a heuristic understanding of their underlying thermodynamics exists. We report a large-scale data-mining study of the Materials Project, a high-throughput database of density functional theory–calculated energetics of Inorganic Crystal Structure Database structures, to explicitly quantify the thermodynamic scale of metastability for 29,902 observed inorganic crystalline phases. We reveal the influence of chemistry and composition on the accessible thermodynamic range of crystalline metastability for polymorphic and phase-separating compounds, yielding new physical insights that can guide the design of novel metastable materials. We further assert that not all low-energy metastable compounds can necessarily be synthesized, and propose a principle of ‘remnant metastability’—that observable metastable crystalline phases are generally remnants of thermodynamic conditions where they were once the lowest free-energy phase. PMID:28138514

  11. Laboratory measurements of electrical conductivities of hydrous and dry Mount Vesuvius melts under pressure

    NASA Astrophysics Data System (ADS)

    Pommier, A.; Gaillard, F.; Pichavant, M.; Scaillet, B.

    2008-05-01

    Quantitative interpretation of MT anomalies in volcanic regions requires laboratory measurements of electrical conductivities of natural magma compositions. The electrical conductivities of three lava compositions from Mount Vesuvius (Italy) have been measured using an impedance spectrometer. Experiments were conducted on both glasses and melts between 400 and 1300°C, at both ambient pressure in air and high pressures (up to 400 MPa). Both dry and hydrous (up to 5.6 wt % H2O) melt compositions were investigated. A change of the conduction mechanism corresponding to the glass transition was systematically observed. The conductivity data were fitted by sample-specific Arrhenius laws on either side of Tg. The electrical conductivity increases with temperature and is higher in the order tephrite, phonotephrite to phonolite. For the three investigated compositions, increasing pressure decreases the conductivity, although the effect of pressure is relatively small. The three investigated compositions have similar activation volumes (ΔV = 16-24 cm3 mol-1). Increasing the water content of the melt increases the conductivity. Comparison of activation energies (Ea) from conductivity and sodium diffusion and use of the Nernst-Einstein relation allow sodium to be identified as the main charge carrier in our melts and presumably also in the corresponding glasses. Our data and those of previous studies highlight the correlation between the Arrhenius parameters Ea and σ0. A semiempirical method allowing the determination of the electrical conductivity of natural magmatic liquids is proposed, in which the activation energy is modeled on the basis of the Anderson-Stuart model, σ0 being obtained from the compensation law and ΔV being fitted from our experimental data. The model enables the electrical conductivity to be calculated for the entire range of melt compositions at Mount Vesuvius and also satisfactorily predicts the electrical response of other melt compositions

  12. 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.

  13. 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.

  14. On the possibility of a folded crustal layer stored in the hydrous mantle transition zone

    NASA Astrophysics Data System (ADS)

    Yoshida, Masaki; Tajima, Fumiko

    2013-06-01

    Previous numerical studies of mantle convection focusing on subduction dynamics have indicated that viscosity (rheological) heterogeneity in the subducting plates and the surrounding mantle may have a primary effect on the behavior of subducting plates. Meanwhile, the existence of a low-viscosity layer (LVL) beneath the mantle transition zone (MTZ) has been suggested by several geodynamic studies. We investigated the effects of a rheologically weaker crustal layer in a hydrous (wet) MTZ with an underlying LVL on the behavior of subducting plates and determined the trace of crustal material using a numerical simulation model of subduction dynamics in three-dimensional regional spherical geometry. The combined effect of a rheologically weaker crustal layer and an LVL beneath the MTZ produces characteristic transient behavior of the crustal layer, whose trace shows a folded, loop-like feature in the wet MTZ along with a folded subducting slab in the LVL. This phenomenon is caused by mechanical interaction of the crustal layer with an upward positive bending force due to the main body of the subducting slab folding in the LVL and an enhanced downward negative buoyancy force due to an increase in density from the garnet to the post-garnet phase of crustal material. The transiently folded crustal layer behind the root of the stagnant slab is also observed. This result is consistent with seismological evidence suggesting a piece of subducted oceanic crust in the uppermost lower mantle beneath the subducting slab in the Mariana trench. Over half of the subducted crust is temporarily stored in the MTZ. However, this stored crustal material begins to penetrate into the lower mantle within 10 Myr, a relatively short timeframe relative to the overturn time of mantle convection. Eventually, most of the crustal material is entrained into the lower mantle, but a non-negligible portion remains stored in the MTZ for >50 Myr after the beginning of the accumulation of subducted crust

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Distribution of inorganic species in two Antarctic cryptoendolithic microbial communities.

    PubMed

    Johnston, C G; Vestal, J R

    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.

  20. Inorganic nitrate and the cardiovascular system.

    PubMed

    Kapil, V; Webb, A J; Ahluwalia, A

    2010-11-01

    Fruit and vegetable-rich diets reduce blood pressure and risk of ischaemic stroke and ischaemic heart disease. While the cardioprotective effects of a fruit and vegetable-rich diet are unequivocal, the exact mechanisms of this effect remain uncertain. Recent evidence has highlighted the possibility that dietary nitrate, an inorganic anion found in large quantities in vegetables (particularly green leafy vegetables), may have a part to play. This beneficial activity lies in the processing in vivo of nitrate to nitrite and thence to the pleiotropic molecule nitric oxide. In this review, recent preclinical and clinical evidence identifying the mechanisms involved in nitrate bioactivity, and the evidence supporting the potential utility of exploitation of this pathway for the prevention and/or treatment of cardiovascular diseases are discussed.

  1. 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.

  2. 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

  3. Strongly coupled inorganic-nano-carbon hybrid materials for energy storage.

    PubMed

    Wang, Hailiang; Dai, Hongjie

    2013-04-07

    The global shift of energy production from fossil fuels to renewable energy sources requires more efficient and reliable electrochemical energy storage devices. In particular, the development of electric or hydrogen powered vehicles calls for much-higher-performance batteries, supercapacitors and fuel cells than are currently available. In this review, we present an approach to synthesize electrochemical energy storage materials to form strongly coupled hybrids (SC-hybrids) of inorganic nanomaterials and novel graphitic nano-carbon materials such as carbon nanotubes and graphene, through nucleation and growth of nanoparticles at the functional groups of oxidized graphitic nano-carbon. We show that the inorganic-nano-carbon hybrid materials represent a new approach to synthesize electrode materials with higher electrochemical performance than traditional counterparts made by simple physical mixtures of electrochemically active inorganic particles and conducting carbon materials. The inorganic-nano-carbon hybrid materials are novel due to possible chemical bonding between inorganic nanoparticles and oxidized carbon, affording enhanced charge transport and increased rate capability of electrochemical materials without sacrificing specific capacity. Nano-carbon with various degrees of oxidation provides a novel substrate for nanoparticle nucleation and growth. The interactions between inorganic precursors and oxidized-carbon substrates provide a degree of control over the morphology, size and structure of the resulting inorganic nanoparticles. This paper reviews the recent development of inorganic-nano-carbon hybrid materials for electrochemical energy storage and conversion, including the preparation and functionalization of graphene sheets and carbon nanotubes to impart oxygen containing groups and defects, and methods of synthesis of nanoparticles of various morphologies on oxidized graphene and carbon nanotubes. We then review the applications of the SC

  4. Principles of Inorganic Materials Design

    NASA Astrophysics Data System (ADS)

    Lalena, John N.; Cleary, David

    2005-04-01

    A unique interdisciplinary approach to inorganic materials design Textbooks intended for the training of chemists in the inorganic materials field often omit many relevant topics. With its interdisciplinary approach, this book fills that gap by presenting concepts from chemistry, physics, materials science, metallurgy, and ceramics in a unified treatment targeted towards the chemistry audience. Semiconductors, metal alloys and intermetallics, as well as ceramic substances are covered. Accordingly, the book should also be useful to students and working professionals in a variety of other disciplines. This book discusses a number of topics that are pertinent to the design of new inorganic materials but are typically not covered in standard solid-state chemistry books. The authors start with an introduction to structure at the mesoscopic level and progress to smaller-length scales. Next, detailed consideration is given to both phenomenological and atomistic-level descriptions of transport properties, the metal-nonmetal transition, magnetic and dielectric properties, optical properties, and mechanical properties. Finally, the authors present introductions to phase equilibria, synthesis, and nanomaterials. Other features include: Worked examples demonstrating concepts unfamiliar to the chemist Extensive references to related literature, leading readers to more in-depth coverage of particular topics Biographies introducing the reader to great contributors to the field of inorganic materials science in the twentieth century With their interdisciplinary approach, the authors have set the groundwork for communication and understanding among professionals in varied disciplines who are involved with inorganic materials engineering. Armed with this publication, students and researchers in inorganic and physical chemistry, physics, materials science, and engineering will be better equipped to face today's complex design challenges. This textbook is appropriate for senior

  5. 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

  6. 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

  7. Evaluation of the microbial growth response to inorganic nanoparticles

    PubMed Central

    Williams, Darryl N; Ehrman, Sheryl H; Pulliam Holoman, Tracey R

    2006-01-01

    In order to enhance the utilization of inorganic nanoparticles in biological systems, it is important to develop a fundamental understanding of the influence they have on cellular health and function. Experiments were conducted to test silica, silica/iron oxide, and gold nanoparticles for their effects on the growth and activity of Escherichia coli (E. coli). Transmission electron microscopy (TEM) and dynamic light scattering (DLS) were used to characterize the morphology and quantify size distribution of the nanoparticles, respectively. TEM was also used to verify the interactions between composite iron oxide nanoparticles and E. coli. The results from DLS indicated that the inorganic nanoparticles formed small aggregates in the growth media. Growth studies measured the influence of the nanoparticles on cell proliferation at various concentrations, showing that the growth of E. coli in media containing the nanoparticles indicated no overt signs of toxicity. PMID:16507102

  8. 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.

  9. Inorganic nanotube nanofluidics

    NASA Astrophysics Data System (ADS)

    Fan, Rong

    The ability to manipulate charge carriers (electrons and holes) in metal-oxide semiconductor field effect transistors (MOSFETs) has revolutionized how information is processed and stored, and created the modern digital age. Introducing direct field effect modulation in fluidic systems would enable the manipulation of ionic and molecular species at a similar level and even logic operation. Due to strong Debye screening in aqueous solutions, field effect manipulation of ion transport arises only in systems whose dimensions are comparable to the critical Debye Length, i.e. in nanofluidic systems. Nanofluidics has already been explored in various cases, e.g. biological channel proteins and artificial solid-state nanopores. All these two terminal systems usually transport the ions the same way as passive electron conduction in a resistor. My work is aimed at developing nanotube nanofluidic units with a third terminal that can electrically turn on/off and control ion and biomolecule transport. Moreover, the systematic study on "doping" and transient phenomena can provide rich information to assess the electrokinetics theory and fluidic physics in nanoscale. Silica nanotubes were synthesized by oxidation/etching approach using vertical silicon nanowires as templates. A single nanotube was integrated into a metal-oxide-solution field effect transistor (MOSolFET) by interfacing with two microfluidic channels and a metallic gate electrode. Concentration dependence of ionic conductance through single nanotubes revealed the emergence of unipolar environment at low ionic strength regime. In this case, ionic conductance is only associated with majority ions and governed by surface potentials and charge densities. By applying a gate voltage, the ionic conductance can be quickly modulated. The gate voltages alter the surface potential of the silica nanotubes via capacitive coupling through the nanotube wall and the electrical double layer. In a negatively charged silica nanotube

  10. 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.

  11. 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

  12. 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.

  13. Modern Inorganic Aerogels.

    PubMed

    Eychmüller, Alexander; Ziegler, Christoph; Wolf, André; Liu, Wei; Herrmann, Anne-Kristin; Gaponik, Nikolai

    2017-02-03

    Essentially, the term aerogel describes a special geometric structure of matter. It is neither limited to any material nor to any synthesis procedure. Hence, the possible variety of materials and therefore the multitude of their applications are almost unbounded. In fact, the same applies for nanoparticles. These are also just defined by their geometrical properties. In the past decades nano-sized materials were intensively studied and possible applications appeared in nearly all areas of natural sciences. To date a large variety of metal, semiconductor, oxide and other nanoparticles are available from colloidal synthesis. However, for many applications of these materials an assembly into macroscopic structures is needed. Here we present a comprehensive picture of the developments that enabled the fusion of the colloidal nanoparticle and the aerogel world. This became possible by the controlled destabilization of pre-formed nanoparticles, which leads to their assembly into three-dimensional macroscopic networks. This revolutionary approach makes it possible to use precisely controlled nanoparticles as building blocks for macroscopic porous structures with programmable properties.

  14. 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)

  15. 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.

  16. 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)

  17. The competing effects of sulfide saturation versus degassing on the behavior of the chalcophile elements during the differentiation of hydrous melts

    NASA Astrophysics Data System (ADS)

    Jenner, Frances E.; Hauri, Erik H.; Bullock, Emma S.; König, Stephan; Arculus, Richard J.; Mavrogenes, John A.; Mikkelson, Nicole; Goddard, Charlotte

    2015-05-01

    There is a lack of consensus regarding the roles of sulfide saturation versus volatile degassing on the partitioning of Cu and Ag during differentiation and eruption of convergent margin magmas. Because of their oxidized character, volatile-rich magmas from the Eastern Manus Back-arc Basin (EMBB) only reach sulfide saturation following magnetite-driven reduction of the melt: the so-called "magnetite crisis." If sulfide saturation typically precedes volatile saturation, the magnetite crisis will limit the proportion of Cu and Ag that can partition from the melt into an exsolving volatile-rich phase, which may contribute to the sporadic occurrence of magmatic-hydrothermal ore deposits at convergent margins. However, it is unclear whether the magnetite crisis is a common or rare event during differentiation of volatile-rich magmas. We report major and trace element data for submarine volcanic glasses from the Tonga arc-proximal Valu Fa Ridge (VFR; SW Pacific). Cu-Se-Ag systematics of samples erupting at the southern VFR suggest magnetite fractionation-triggered sulfide saturation. The similarity in chalcophile element systematics of the southern VFR and EMBB samples is unlikely to be coincidental, and may indicate that the magnetite crisis is a common event during differentiation of hydrous melts. However, unlike many convergent margin magmas, it is unlikely that the evolving VFR and EMBB were saturated in a S-bearing volatile phase prior to magnetite fractionation. Hence, the metal-depleting magnetite crisis may be restricted to back-arc basin magmas that do not degas volatiles prior to magnetite fractionation and potentially convergent margin magmas fractionating at high pressures in the continental crust.

  18. 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.

  19. Hydrous metasomatism and melt percolation in the lithospsheric mantle wedge underneath Comallo, Rio Negro Province, Argentina

    NASA Astrophysics Data System (ADS)

    Papadopoulou, Martha; Ntaflos, Theodoros; Bjerg, Ernesto; Gregoire, Michel

    2014-05-01

    for the lithospheric mantle below Comallo indicating a cold environment which, combined with the equigranular textures of the samples and the fact that spinel is frequently enclosed by olivine, suggests that recrystallization and re-equilibration took place at relatively low temperatures. The modal hydrous metasomatism represented by the occurrence of disseminated amphibole and/or phlogopite appears to be related to the downgoing subducted Pacific slab considering that Comallo is located approximately 200 km from the subduction front in the back-arc region.

  20. 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

  1. 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

  2. Creep of porous rocks and measurements of elastic wave velocities under different hydrous conditions

    NASA Astrophysics Data System (ADS)

    Eslami, J.; Grgic, D.; Hoxha, D.

    2009-04-01

    of strains on a same sample, under uniaxial compression. Different hydrous conditions (saturated or partially saturated) are tested in all creep tests. In this paper, we focus on the time-dependent behavior and short-term mechanical behavior of iron ore and limestone in saturated and partially saturated domains. The main outcomes of these experiments are: (i) identification of the apparent dynamic stiffness tensor from elastic wave velocity measurements; (ii) assessment of velocity anisotropy, and its evolution under uniaxial loading. This last step allows for the quantification of the intrinsic and stress-induced anisotropies, leading eventually to an estimation of the microcracks density and distribution evolutions in the rock sample under loading.

  3. 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

  4. Viscosity of hydrous Etna basalt: implications for Plinian-style basaltic eruptions

    NASA Astrophysics Data System (ADS)

    Giordano, D.; Dingwell, D. B.

    Water dissolved in a silicate melt can strongly influence its physical properties and thus magma behavior during crystallization, degassing, foaming and fragmentation. Etna is a basaltic volcano whose activity is dominated by effusive eruptions which have long represented a threat to the densely populated, surrounding area. Recently, recognition of the products of a Plinian eruption (122 B.C.) has raised further issues for hazard assessment at Etna and other basaltic volcanoes. Constraining the behavior of Etna magma under conditions relevant to both effusive and explosive hazards requires viscosity data under conditions near the glass transition. Here we have investigated the viscosity of hydrous Etna lava in order to better understand eruptive processes which characterize this volcano. The experimental methods which have been used include piston cylinder synthesis of the hydrated melts, micropenetration viscometry for low-temperature viscosity measurements, and near-infrared spectroscopy for the evaluation of sample homogeneity and measurements of water content. Additionally, scanning calorimetric determinations were performed to check whether incipient crystallization had occurred. Sample compositions were determined using electron microprobe analysis and 57Fe Mössbauer spectroscopy. Results from this study are compared with previous reports of trachytic, phonolitic and model calc-alkaline rhyolite (HPG8) compositions. The viscosity of the basaltic melt (dry and wet) has been parameterized in terms of temperature and water content via the non-Arrhenian equation: log10ɛ=-4.643+(5,812.44- 427.04×H2O)/(T(K)- 499.31+28.74×ln(H2O)) where ɛ is the viscosity in Pa s, H2O is the water content in wt%, and T is the temperature in Kelvin. We observe that the viscosity of alkali basalt (at more than 0.5 wt% H2O) is similar to that of an alkaline trachyte (Agnano-Monte Spina eruption, Phlegrean Fields) and much higher than that of a peralkaline phonolite (Teide

  5. Viscosity of hydrous Etna basalt: implications for Plinian-style basaltic eruptions

    NASA Astrophysics Data System (ADS)

    Giordano, D.; Dingwell, D. B.

    2002-07-01

    Water dissolved in a silicate melt can strongly influence its physical properties and thus magma behavior during crystallization, degassing, foaming and fragmentation. Etna is a basaltic volcano whose activity is dominated by effusive eruptions which have long represented a threat to the densely populated, surrounding area. Recently, recognition of the products of a Plinian eruption (122 B.C.) has raised further issues for hazard assessment at Etna and other basaltic volcanoes. Constraining the behavior of Etna magma under conditions relevant to both effusive and explosive hazards requires viscosity data under conditions near the glass transition. Here we have investigated the viscosity of hydrous Etna lava in order to better understand eruptive processes which characterize this volcano. The experimental methods which have been used include piston cylinder synthesis of the hydrated melts, micropenetration viscometry for low-temperature viscosity measurements, and near-infrared spectroscopy for the evaluation of sample homogeneity and measurements of water content. Additionally, scanning calorimetric determinations were performed to check whether incipient crystallization had occurred. Sample compositions were determined using electron microprobe analysis and 57Fe Mössbauer spectroscopy. Results from this study are compared with previous reports of trachytic, phonolitic and model calc-alkaline rhyolite (HPG8) compositions. The viscosity of the basaltic melt (dry and wet) has been parameterized in terms of temperature and water content via the non-Arrhenian equation: log10ɛ=-4.643+(5,812.44-427.04×H2O)/(T(K)-499.31+28.74×ln(H2O)) where ɛ is the viscosity in Pa s, H2O is the water content in wt%, and T is the temperature in Kelvin. We observe that the viscosity of alkali basalt (at more than 0.5 wt% H2O) is similar to that of an alkaline trachyte (Agnano-Monte Spina eruption, Phlegrean Fields) and much higher than that of a peralkaline phonolite (Teide, Tenerife

  6. Visualization and Analysis of Structural and Dynamical Properties of Hydrous Silicate Melt

    NASA Astrophysics Data System (ADS)

    Karki, B. B.; Bhattarai, D.; Stixrude, L. P.

    2008-12-01

    We have carried out a detailed visualization-based analysis of position-time data produced by first principles molecular dynamics simulations of hydrous MgSiO3 liquid to gain insight into its structural and dynamical behavior. A wide range of pressure (0 to ~100 GPa) and temperature (2000 to 6000 K) is covered and the water content is also varied (5 and 10 wt percent water in the melt). By exploring a number of structural parameters associated with short- and mid-range orders, we have shown that the melt structure changes substantially on compression. The speciation of the water component at low pressures is dominated by the isolated structures (with over 90 percent hydrogen participated) consisting of hydroxyls, water molecules, O- H-O bridging, and four-atom (O-H-O-H and H-O-H-O) groups, where every oxygen atom may be a part of polyhedron or free (i.e., bound to only magnesium atom). Hydroxyls slightly favor polyhedral sites over magnesium sites whereas molecular water is almost entirely bound to magnesium sites, and also interpolyhedral bridging (Si-O-H-O-Si) dominates other bridging. As compression increases, these isolated structures increasingly combine with each other to form extended structures involving a total of five or more O and H atoms and/or containing three-fold coordination species, which together consume over 60 percent hydrogen at the highest compression studied. Protons in the melt can be considered on equal footing with other cations (or more precisely as network modifier cations), and they are shown to increase and decrease, respectively, the contents of non-bridging and bridging oxygen. Relatively long runs are used to calculate the self-diffusion coefficients of all atomic species, which are enhanced in the presence of water compared to those of anhydrous melt. This is consistent with the prediction that water depolymerizes the melt structure at all pressures. Our analysis suggests that proton diffusion involves two processes - the transfer

  7. Inorganic chemistry of defensive peroxidases in the human oral cavity.

    PubMed

    Ashby, M T

    2008-10-01

    The innate host response system is comprised of various mechanisms for orchestrating host response to microbial infection of the oral cavity. The heterogeneity of the oral cavity and the associated microenvironments that are produced give rise to different chemistries that affect the innate defense system. One focus of this review is on how these spatial differences influence the two major defensive peroxidases of the oral cavity, salivary peroxidase (SPO) and myeloperoxidase (MPO). With hydrogen peroxide (H(2)O(2)) as an oxidant, the defensive peroxidases use inorganic ions to produce antimicrobials that are generally more effective than H(2)O(2) itself. The concentrations of the inorganic substrates are different in saliva vs. gingival crevicular fluid (GCF). Thus, in the supragingival regime, SPO and MPO work in unison for the exclusive production of hypothiocyanite (OSCN(-), a reactive inorganic species), which constantly bathes nascent plaques. In contrast, MPO is introduced to the GCF during inflammatory response, and in that environment it is capable of producing hypochlorite (OCl(-)), a chemically more powerful oxidant that is implicated in host tissue damage. A second focus of this review is on inter-person variation that may contribute to different peroxidase function. Many of these differences are attributed to dietary or smoking practices that alter the concentrations of relevant inorganic species in the oral cavity (e.g.: fluoride, F(-); cyanide, CN(-); cyanate, OCN(-); thiocyanate, SCN(-); and nitrate, NO(3)(-)). Because of the complexity of the host and microflora biology and the associated chemistry, it is difficult to establish the significance of the human peroxidase systems during the pathogenesis of oral diseases. The problem is particularly complex with respect to the gingival sulcus and periodontal pockets (where the very different defensive stratagems of GCF and saliva co-mingle). Despite this complexity, intriguing in vitro and in vivo

  8. Synthesis of hybrid organic-inorganic near-IR responsive magnetic nanoparticles for cancer theragnosis

    NASA Astrophysics Data System (ADS)

    Bang, Doyeon; Lee, Taeksu; Choi, Jihye; Park, Joseph; Kang, Byunghoon; Huh, Yong-Min; Haam, Seungjoo

    2012-10-01

    Hybrid organic-inorganic near-infrared responsive magnetic nanoparticles were synthesized for theragnosis combined with localized therapy. In detail, inorganic super-paramagnetic nanoparticles were embedded inside organic polyaniline matrix, which enables localized photothermal therapy upon NIR illumination under intracellular acidic/oxidative condition. In this structure, super-paramagnetic nanoparticle works as MRI contrast agent, that enables the visualization of a tumor and polyaniline works for near-infrared responsive tumor ablation.

  9. Metal-organic framework templated synthesis of porous inorganic materials as novel sorbents

    DOEpatents

    Taylor-Pashow, Kathryn M. L.; Lin, Wenbin; Abney, Carter W.

    2017-03-21

    A novel metal-organic framework (MOF) templated process for the synthesis of highly porous inorganic sorbents for removing radionuclides, actinides, and heavy metals is disclosed. The highly porous nature of the MOFs leads to highly porous inorganic sorbents (such as oxides, phosphates, sulfides, etc) with accessible surface binding sites that are suitable for removing radionuclides from high level nuclear wastes, extracting uranium from acid mine drainage and seawater, and sequestering heavy metals from waste streams. In some cases, MOFs can be directly used for removing these metal ions as MOFs are converted to highly porous inorganic sorbents in situ.

  10. Si and O self-diffusion in hydrous forsterite and iron-bearing olivine from the perspective of defect chemistry

    NASA Astrophysics Data System (ADS)

    Fei, Hongzhan; Katsura, Tomoo

    2016-02-01

    We discuss the experimental results of silicon and oxygen self-diffusion coefficients in forsterite and iron-bearing olivine from the perspective of defect chemistry. Silicon diffusion is dominated by VO ··-associated VSi″″, whereas oxygen diffusion is dominated by hopping of VO ·· under anhydrous conditions, and by (OH)O · under hydrous conditions. By considering the charge neutrality condition of [(OH)O ·] = 2[VMe″] in hydrous forsterite and iron-bearing olivine, we get D Si ∝ (C_{{{{H}}2 {{O}}}})1/3 and D O ∝ (C_{{{{H}}2 {{O}}}})0, which explains the experimental results of water effects on oxygen and silicon self-diffusion rates (Fei et al. in Nature 498:213-215, 2013; J Geophys Res 119:7598-7606, 2014). The C_{{{{H}}2 {{O}}}} dependence of creep rate in the Earth's mantle should be close to that given by Si and O self-diffusion coefficients obtained under water unsaturated conditions.

  11. Amorphous indium-gallium-zinc-oxide thin-film transistors using organic-inorganic hybrid films deposited by low-temperature plasma-enhanced chemical vapor deposition for all dielectric layers

    NASA Astrophysics Data System (ADS)

    Hsu, Chao-Jui; Chang, Ching-Hsiang; Chang, Kuei-Ming; Wu, Chung-Chih

    2017-01-01

    We investigated the deposition of high-performance organic-inorganic hybrid dielectric films by low-temperature (close to room temperature) inductively coupled plasma chemical vapor deposition (ICP-CVD) with hexamethyldisiloxane (HMDSO)/O2 precursor gas. The hybrid films exhibited low leakage currents and high breakdown fields, suitable for thin-film transistor (TFT) applications. They were successfully integrated into the gate insulator, the etch-stop layer, and the passivation layer for bottom-gate staggered amorphous In-Ga-Zn-O (a-IGZO) TFTs having the etch-stop configuration. With the double-active-layer configuration having a buffer a-IGZO back-channel layer grown in oxygen-rich atmosphere for better immunity against plasma damage, the etch-stop-type bottom-gate staggered a-IGZO TFTs with good TFT characteristics were successfully demonstrated. The TFTs showed good field-effect mobility (μFE), threshold voltage (V th), subthreshold swing (SS), and on/off ratio (I on/off) of 7.5 cm2 V-1 s-1, 2.38 V, 0.38 V/decade, and 2.2 × 108, respectively, manifesting their usefulness for a-IGZO TFTs.

  12. Ultrathin inorganic molecular nanowire based on polyoxometalates

    PubMed Central

    Zhang, Zhenxin; Murayama, Toru; Sadakane, Masahiro; Ariga, Hiroko; Yasuda, Nobuhiro; Sakaguchi, Norihito; Asakura, Kiyotaka; Ueda, Wataru

    2015-01-01

    The development of metal oxide-based molecular wires is important for fundamental research and potential practical applications. However, examples of these materials are rare. Here we report an all-inorganic transition metal oxide molecular wire prepared by disassembly of larger crystals. The wires are comprised of molybdenum(VI) with either tellurium(IV) or selenium(IV): {(NH4)2[XMo6O21]}n (X=tellurium(IV) or selenium(IV)). The ultrathin molecular nanowires with widths of 1.2 nm grow to micrometre-scale crystals and are characterized by single-crystal X-ray analysis, Rietveld analysis, scanning electron microscopy, X-ray photoelectron spectroscopy, ultraviolet–visible spectroscopy, thermal analysis and elemental analysis. The crystals can be disassembled into individual molecular wires through cation exchange and subsequent ultrasound treatment, as visualized by atomic force microscopy and transmission electron microscopy. The ultrathin molecular wire-based material exhibits high activity as an acid catalyst, and the band gap of the molecular wire-based crystal is tunable by heat treatment. PMID:26139011

  13. 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.

  14. Aqueous alteration on the parent bodies of carbonaceous chondrites: Computer simulations of late-stage oxidation

    NASA Technical Reports Server (NTRS)

    Bourcier, W. L.; Zolensky, Michael E.

    1991-01-01

    CI carbonaceous chondrites may be products of hydrous alteration of CV- or anhydrous CM-type materials. The CIs typically contain veins filled with carbonates and sulfates, probably indicating a period of late stage aqueous alteration under oxidizing conditions. To test this idea, computer simulations of aqueous alteration of CV- and CM-type carbonaceous were performed. Simulations were restricted to the oxidation of hydrous mineral assemblages produced in previous simulations in order to determine whether further reaction and oxidation results in the phyllosilicate, carbonate, sulfate and oxide vein assemblages typical of CI carbonaceous chondrites. Our simulations were performed at 1, 25, 100, and 150 C (the appropriate temperature range) for the CV and CM mineral assemblages and using the computer code EQ3/6.

  15. Gas separations using inorganic membranes

    SciTech Connect

    Egan, B.Z.; Singh, S.P.N.; Fain, D.E.; Roettger, G.E.; White, D.E.

    1992-04-01

    This report summarizes the results from a research and development program to develop, fabricate, and evaluate inorganic membranes for separating gases at high temperatures and pressures in hostile process environments encountered in fossil energy conversion processes such as coal gasification. The primary emphasis of the research was on the separation and recovery of hydrogen from synthesis gas. Major aspects of the program included assessment of the worldwide research and development activity related to gas separations using inorganic membranes, identification and selection of candidate membrane materials, fabrication and characterization of membranes using porous membrane technology developed at the Oak Ridge K-25 Site, and evaluation of the separations capability of the fabricated membranes in terms of permeabilities and fluxes of gases.

  16. Clinical evidence demonstrating the utility of inorganic nitrate in cardiovascular health.

    PubMed

    Kapil, V; Weitzberg, E; Lundberg, J O; Ahluwalia, A

    2014-04-30

    The discovery of nitric oxide and its role in almost every facet of human biology opened a new avenue for treatment through manipulation of its canonical signaling and by attempts to augment endogenous nitric oxide generation through provision of substrate and co-factors to the endothelial nitric oxide synthase complex. This has been particularly so in the cardiovascular system and it is well recognized that there is reduced bioavailable nitric oxide in patients with both cardiovascular risk factors and manifest vascular disease. However, these attempts have failed to deliver the expected benefits of such an approach. Recently, an alternative pathway for nitric oxide synthesis has been elucidated that can produce authentic nitric oxide from the 1 electron reduction of inorganic nitrite. Furthermore, it has long been known that symbiotic, facultative, oral microflora can facilitate the reduction of inorganic nitrate, that is ingested in the average diet in millimolar amounts, to inorganic nitrite itself. Thus, there exists an alternative reductive pathway from nitrate, via nitrite as an intermediate, to nitric oxide that provides a novel pathway that may be amenable to therapeutic manipulation. As such, various research groups have explored the utility of manipulation of this nitrate-nitrite-nitric oxide pathway in situations in which nitric oxide is known to have a prominent role. Animal and early-phase human studies of both inorganic nitrite and nitrate supplementation have shown beneficial effects in blood pressure control, platelet function, vascular health and exercise capacity. This review considers in detail the pathways of inorganic nitrate bioactivation and the evidence of clinical utility to date on the cardiovascular system.

  17. Sealed Lithium Inorganic Electrolyte Cell

    DTIC Science & Technology

    1976-03-01

    revere side it necoeery and idM,1117 "~ bfoh numiber) Inorganic Electrolyte Battery Carbon Cathode Evaluation Thionyl Chloride Gas Generation Lithium ...hardware corrosion in cold rolled steel cans, due to cathodic protection of the cans by the lithium . Recent data 4 showed that thionyl chloride is reduced...very slowly on the surface of nickel and stainless steel, when these materials were in contact with a lithium anode in the thionyl chloride

  18. 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.

  19. 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

  20. Fast dynamics of H{sub 2}O in hydrous aluminosilicate glasses studied with quasielastic neutron scattering

    SciTech Connect

    Indris, Sylvio; Heitjans, Paul; Behrens, Harald; Zorn, Reiner; Frick, Bernhard

    2005-02-01

    We studied the dynamics of dissolved water in aluminosilicate glasses with the compositions NaAlSi{sub 3}O{sub 8}{center_dot}0.3H{sub 2}O, NaAlSi{sub 3}O{sub 8}{center_dot}1.3H{sub 2}O and Ca{sub 0.5}AlSi{sub 3}O{sub 8}{center_dot}1.3H{sub 2}O using quasielastic neutron scattering. As shown by near-infrared spectroscopy on these samples, H{sub 2}O molecules are the predominant hydrous species in the water-rich glasses whereas OH groups bound to tetrahedrally coordinated cations are predominant at low water contents. Backscattering and time-of-flight methods were combined to investigate motional correlation times in the range between 0.2 ps and 2 ns. For the water-rich glasses an elastic scan between 2 K and 420 K shows that the dynamical processes set in at lower temperatures in the Ca-bearing glass than in the Na-bearing glass. This is corroborated by the broadening of the inelastic spectra S(Q,{omega}). The shape of the scattering function S(Q,t) suggests a distribution of activation barriers for the motion of hydrous species in the disordered structure of the glass. The distribution is narrower and the average activation energy is smaller in the Ca-bearing glass than in the Na-bearing glass. No indication for dynamics of hydrous species was found at temperatures up to 520 K in the water-poor glass NaAlSi{sub 3}O{sub 8}{center_dot}0.3H{sub 2}O containing dissolved water mainly in the form of OH groups. It is concluded that H{sub 2}O molecules are the dynamic species in the above-mentioned time regime in the water-rich glasses. The dynamic process is probably a rotation of H{sub 2}O molecules around their bisector axis.

  1. Inclusions of nanocrystalline hydrous aluminium silicate “Phase Egg” in superdeep diamonds from Juina (Mato Grosso State, Brazil)

    NASA Astrophysics Data System (ADS)

    Wirth, Richard; Vollmer, Christian; Brenker, Frank; Matsyuk, Stanislav; Kaminsky, Felix

    2007-07-01

    Inclusions in alluvial diamond from Juina (Mato Grosso, Brazil) have been investigated by TEM methods (electron diffraction, HRTEM, AEM, HAADF, EELS) and Raman spectroscopy. The inclusion paragenesis of Juina diamonds is dominated by ultrahigh-pressure ("superdeep") phases. One of these diamonds, sample #1.1/4, contains several micrometer-sized (approximately 200 μm by 50-70 μm) inclusions, which have been studied. TEM foils prepared applying Focused Ion Beam (FIB) technique revealed that these inclusions consist of a porous, nanocrystalline groundmass, which is composed of nanometre-sized crystals of a hydrous aluminium silicate phase with Al:Si approximately 1:1 and chemical composition of phase "Egg" (AlSiO 3(OH)), a minor volume fraction of nanocrystalline stishovite and pore space, which was originally filled with a fluid or gas. The nanocrystalline hydrous aluminium silicate phase is idiomorphic, randomly oriented (approximately 20-30 nm in size) predominantly with tetragonal crystal structure ( a0 = 0.743 nm, c0 = 0.706 nm). The monoclinic structure of synthetic phase "Egg" determined at ambient conditions [M.W. Schmidt, L.W. Finger, R.J. Ross, R.E. Dinnebier, Synthesis, crystal structure, and phase relations of AlSiO 3OH, a high-pressure hydrous phase, American Mineralogist 83 (1998) 881 - 888] is only occasionally observed. The fluid filling in the porosity has been released into the vacuum of the FIB during TEM specimen preparation. Quench products of the fluid containing minor concentrations of F- P- S- Cl- K- Ca and Ba were detected at the walls of the pores. In addition phase "Egg" is identified by μ-Raman spectroscopy within a second sample (RS 43a) from the same location. The presence of Phase "Egg" in the inclusions in diamond may suggest that crustal material has been subducted to a depth of the lower Transition Zone. Although, metastable growth of nanocrystalline high-pressure phases or extension of their respective stability fields to lower

  2. IRIS Toxicological Review of Ingested Inorganic Arsenic (2005 ...

    EPA Pesticide Factsheets

    EPA's Office of Research and Development (ORD), Office of Pesticide Programs (OPP), and Office of Water (OW) requested the SAB to provide advice to the Agency on several issues about the mode of carcinogenic action of various arsenic species and the implications of these issues for EPA's assessment of the cancer hazard and risks of organic and inorganic arsenic. The panel will review an OPP Science Issue Paper (with an attachment prepared by ORD) and a revised hazard and dose response assessment/characterization for inclusion in the Integrated Risk Information System (IRIS) prepared by OW. Inorganic arsenic is used for hardening copper and lead alloys. It also is used in glass manufacturing as a decolorizing and refining agent, as a component of electrical devices, in the semiconductor industry, and as a catalyst in the production of ethylene oxide.

  3. Organic-inorganic hybrid polymer-encapsulated magnetic nanobead catalysts.

    PubMed

    Arai, Takayoshi; Sato, Toru; Kanoh, Hirofumi; Kaneko, Katsumi; Oguma, Koichi; Yanagisawa, Akira

    2008-01-01

    A new strategy for the encapsulation of magnetic nanobeads was developed by using the in situ self-assembly of an organic-inorganic hybrid polymer. The hybrid polymer of {[Cu(bpy)(BF(4))(2)(H(2)O)(2)](bpy)}(n) (bpy=4,4'-bipyridine) was constructed on the surface of amino-functionalized magnetic beads and the resulting hybrid-polymer-encapsulated beads were utilized as catalysts for the oxidation of silyl enolates to provide the corresponding alpha-hydroxy carbonyl compounds in high yield. After the completion of the reaction, the catalyst was readily recovered by magnetic separation and the recovered catalyst could be reused several times. Because the current method did not require complicated procedures for incorporating the catalyst onto the magnetic beads, the preparation and the application of various other types of organic-inorganic hybrid-polymer-coated magnetic beads could be possible.

  4. Crystallographic analysis of a series of inorganic compounds

    NASA Astrophysics Data System (ADS)

    Borisov, S. V.; Magarill, S. A.; Pervukhina, N. V.

    2015-04-01

    The method of crystallographic analysis relies on the mechanical-wave concept that treats the crystalline state as the result of ordering of atomic positions by families of parallel equidistant planes. Using this method, a large set of fluoride, oxide and sulfide structures was analyzed. The pseudo-translational ordering of various atomic groups (including the presence of cation and anion sublattices) in the structures of various classes of inorganic compounds was established. The crucial role of local ordering of heavy cations (coherent assembly) in the structures comprising large cluster fragments (Keggin polyanions, polyoxoniobates, etc.) is discussed. The role of symmetry and the regular distribution of heavy atoms in the formation of stable crystal structures, which is to be taken into account in the targeted design, is considered. The universality of configurations of atomic positions in the structures of various classes of inorganic compounds resulting from the ordering mechanism organized by mechanical (elastic) forces is demonstrated. The bibliography includes 158 references.

  5. 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.

  6. Hierarchical Inorganic Assemblies for Artificial Photosynthesis.

    PubMed

    Kim, Wooyul; Edri, Eran; Frei, Heinz

    2016-09-20

    Artificial photosynthesis is an attractive approach for renewable fuel generation because it offers the prospect of a technology suitable for deployment on highly abundant, non-arable land. Recent leaps forward in the development of efficient and durable light absorbers and catalysts for oxygen evolution and the growing attention to catalysts for carbon dioxide activation brings into focus the tasks of hierarchically integrating the components into assemblies for closing of the photosynthetic cycle. A particular challenge is the efficient coupling of the multi-electron processes of CO2 reduction and H2O oxidation. Among the most important requirements for a complete integrated system are catalytic rates that match the solar flux, efficient charge transport between the various components, and scalability of the photosynthetic assembly on the unprecedented scale of terawatts in order to have impact on fuel consumption. To address these challenges, we have developed a heterogeneous inorganic materials approach with molecularly precise control of light absorption and charge transport pathways. Oxo-bridged heterobinuclear units with metal-to-metal charge-transfer transitions absorbing deep in the visible act as single photon, single charge transfer pumps for driving multi-electron catalysts. A photodeposition method has been introduced for the spatially directed assembly of nanoparticle catalysts for selective coupling to the donor or acceptor metal of the light absorber. For CO2 reduction, a Cu oxide cluster is coupled to the Zr center of a ZrOCo light absorber, while coupling of an Ir nanoparticle catalyst for water oxidation to the Co donor affords closing of the photosynthetic cycle of CO2 conversion by H2O to CO and O2. Optical, vibrational, and X-ray spectroscopy provide detailed structural knowledge of the polynuclear assemblies. Time resolved visible and rapid-scan FT-IR studies reveal charge transfer mechanisms and transient surface intermediates under

  7. 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.

  8. 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.

  9. A kinetic study of hydrous alteration of amorphous MgSiO smokes - Implications for cometary particles and chondrite matrix

    NASA Technical Reports Server (NTRS)

    Nelson, Robert; Nuth, Joseph A.; Donn, Bertram

    1987-01-01

    Measurements of the rate of hydrous alteration of amorphous Mg-SiO smokes are reported as a function of temperature, as inferred by observing changes in the infrared spectra of these materials. It is shown that under the conditions reported for the nucleus of Comet Halley, based on measurements made by the Vega and Giotto missions, amorphous, anhydrous Mg-SiO smokes would become hydrated within several weeks in the dusty regolith observed on the surface. However, if such grains were released in 'jets' or from loose ice fragments, then previously amorphous grains would retain their anhydrous nature. Similarly, brief periods of aqueous activity on meteorite parent bodies would convert amorphous, fine-grained material to hydrated phyllosilicates much more rapidly than coarse mineral grains. A kinetic model might therefore be developed to explain the observed textural relationships in the matrices of carbonaceous chondrites such as Mokoia, where amorphous phyllosilicates are intimately associated with coarse anhydrous grains.

  10. Sulfur solubility in hydrous Etna Basalt at temperatures from 1150 to 1250 °C and 200 MPa

    NASA Astrophysics Data System (ADS)

    Beermann, O.; Nowak, N.; Botcharnikov, R. E.; Holtz, F.

    2009-04-01

    Degassing of magmatic volatiles is strongly dependent on fluid-melt interaction at the oneset of degassing under given pressure and temperature. Most magmatic fluids are composed of hydrous multicomponental mixtures, e.g. H-O-C-S-Cl-F-Br bearing fluids. In particular the partitioning behaviour of S and Cl between basaltic melt and hydrous fluid is of interest, because the S/Cl ratio of emitted volcanic gasses correlate to the eruption style (e.g. [1], [2], [3]). In particular, this was also observed for the 2002 eruption of Mt. Etna (Sicily) [4], which is one of the worlds most active and best investigated volcanoes. Since now, there even exist no reliable data on the solubility of sulfur in hydrous silicic melts at geologic relevant temperatures for basaltic magmas (above 1050 °C), because sulfur is known to be a very aggressive component limiting the application of experimental approaches that use noble metal capsules, especially Pt and AuPd. Thus, the experiments in this study, concerning the solubility of S in natural hydrous Etna basalt at 200 MPa and temperatures from 1150 to 1250 °C at fO2 ~ NNO + 2.5 and 1200 °C at fO2 ~ NNO, were performed in olivine-AuPd double capsules, using single crystal olivine capsules (San Carlos olivine) as sample containers, which were inserted into outer Au80Pd20 capsules. The starting material was a fused and water presaturated trachybasalt from Mt. Etna (2001 eruption), containing 5 wt.% H2O. For sulfur source pyrrhotine (FeS) was used, obtaining initial S concentrations between 1-1.5 wt.% (with respect to the amount of starting material). For some experiments an olivine disc was placed between FeS and starting glass powder to avoid FeS dispersion in the melt. All experiments were conducted in internally heated argon pressure vessels (IHPV) equipped with rapid quench device. For the reduced runs an Ar-H2 mixture was load into the vessel and the H2 pressure was monitored, using the shaw membrane technique. The experimental

  11. 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.

  12. 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

  13. The inorganic constituents of echinoderms

    USGS Publications Warehouse

    Clarke, F.W.; Wheeler, W.C.

    1915-01-01

    In a recent paper on the composition of crinoid skeletons we showed that crinoids contain large quantities of magnesia, and that its proportion varies with the temperature of the water in which the creatures live. This result was so novel and surprising that it seemed desirable to examine other echinoderms and to ascertain whether they showed the same characteristics and regularity. A number of sea urchins and starfishes were therefore studied, their inorganic constituents being analyzed in the same manner as those of the crinoids

  14. 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

  15. A metamorphic inorganic framework that can be switched between eight single-crystalline states

    NASA Astrophysics Data System (ADS)

    Zhan, Caihong; Cameron, Jamie M.; Gabb, David; Boyd, Thomas; Winter, Ross S.; Vilà-Nadal, Laia; Mitchell, Scott G.; Glatzel, Stefan; Breternitz, Joachim; Gregory, Duncan H.; Long, De-Liang; MacDonell, Andrew; Cronin, Leroy

    2017-02-01

    The design of highly flexible framework materials requires organic linkers, whereas inorganic materials are more robust but inflexible. Here, by using linkable inorganic rings made up of tungsten oxide (P8W48O184) building blocks, we synthesized an inorganic single crystal material that can undergo at least eight different crystal-to-crystal transformations, with gigantic crystal volume contraction and expansion changes ranging from -2,170 to +1,720 Å3 with no reduction in crystallinity. Not only does this material undergo the largest single crystal-to-single crystal volume transformation thus far reported (to the best of our knowledge), the system also shows conformational flexibility while maintaining robustness over several cycles in the reversible uptake and release of guest molecules switching the crystal between different metamorphic states. This material combines the robustness of inorganic materials with the flexibility of organic frameworks, thereby challenging the notion that flexible materials with robustness are mutually exclusive.

  16. Force-controlled inorganic crystallization lithography.

    PubMed

    Cheng, Chao-Min; LeDuc, Philip R

    2006-09-20

    Lithography plays a key role in integrated circuits, optics, information technology, biomedical applications, catalysis, and separation technologies. However, inorganic lithography techniques remain of limited utility for applications outside of the typical foci of integrated circuit manufacturing. In this communication, we have developed a novel stamping method that applies pressure on the upper surface of the stamp to regulate the dewetting process of the inorganic buffer and the evaporation rate of the solvent in this buffer between the substrate and the surface of the stamp. We focused on generating inorganic microstructures with specific locations and also on enabling the ability to pattern gradients during the crystallization of the inorganic salts. This approach utilized a combination of lithography with bottom-up growth and assembly of inorganic crystals. This work has potential applications in a variety of fields, including studying inorganic material patterning and small-scale fabrication technology.

  17. 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.

  18. Perfect Strangers: Inorganic Photochemistry and Nucleic Acids

    NASA Astrophysics Data System (ADS)

    Carter, Pamela J.; Ciftan, Suzanne A.; Sistare, Mark F.; Holden Thorp, H.

    1997-06-01

    The applications of inorganic photochemistry to nucleic acid chemistry are discussed. A brief review of nucleic acid structure is given. Methods for probing DNA using emissive inorganic complexes are discussed. Photoreactions that damage DNA by hydrogen atom transfer from sugar or electron abstraction from guanine are presented. The method of photochemical footprinting using a diplatinum photocatalyst is described. The final section discusses advances in combinatorial selection experiments that increase the urgency for rapid screening methods such as those derived from inorganic photochemistry.

  19. 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.

  20. Biodegradable and Renal Clearable Inorganic Nanoparticles

    PubMed Central

    Ehlerding, Emily B.

    2015-01-01

    Personalized treatment plans for cancer therapy have been at the forefront of oncology research for many years. With the advent of many novel nanoplatforms, this goal is closer to realization today than ever before. Inorganic nanoparticles hold immense potential in the field of nano‐oncology, but have considerable toxicity concerns that have limited their translation to date. In this review, an overview of emerging biologically safe inorganic nanoplatforms is provided, along with considerations of the challenges that need to be overcome for cancer theranostics with inorganic nanoparticles to become a reality. The clinical and preclinical studies of both biodegradable and renal clearable inorganic nanoparticles are discussed, along with their implications. PMID:27429897

  1. 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)

  2. 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.

  3. 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.

  4. Designing inorganic light-protective skin nanotechnology products.

    PubMed

    Popov, Alexey P; Zvyagin, Andrei V; Lademann, Juergen; Roberts, Michael S; Sanchez, Washington; Priezzhev, Alexander V; Myllylä, Risto

    2010-10-01

    In this review, we discuss the use of inorganic nanoparticles, mainly zinc oxide (ZnO) and titanium dioxide (TiO2), for sunscreen applications considering their intrinsic physical properties and the Mie theory. These properties cause, from one side, attenuation of the ultraviolet light by absorption and scattering (dependent on a particle size), which is the purpose sunscreens are designed for, and formation of free radicals (i.e., phototoxicity) during this process--from the other. Particle penetration into skin is also an important issue addressed in this review due to possible adverse effects associated with interaction between nanoparticles and skin living cells.

  5. Design of targeting ligands in medicinal inorganic chemistry.

    PubMed

    Storr, Tim; Thompson, Katherine H; Orvig, Chris

    2006-06-01

    This tutorial review will highlight recent advances in medicinal inorganic chemistry pertaining to the use of multifunctional ligands for enhanced effect. Ligands that adequately bind metal ions and also include specific targeting features are gaining in popularity due to their ability to enhance the efficacy of less complicated metal-based agents. Moving beyond the traditional view of ligands modifying reactivity, stabilizing specific oxidation states, and contributing to substitution inertness, we will discuss recent work involving metal complexes with multifunctional ligands that target specific tissues, membrane receptors, or endogenous molecules, including enzymes.

  6. Antiinflammatory actions of inorganic nitrate stabilize the atherosclerotic plaque

    PubMed Central

    Khambata, Rayomand S.; Ghosh, Suborno M.; Rathod, Krishnaraj S.; Thevathasan, Tharssana; Filomena, Federica; Xiao, Qingzhong; Ahluwalia, Amrita

    2017-01-01

    Reduced bioavailable nitric oxide (NO) plays a key role in the enhanced leukocyte recruitment reflective of systemic inflammation thought to precede and underlie atherosclerotic plaque formation and instability. Recent evidence demonstrates that inorganic nitrate (NO3−) through sequential chemical reduction in vivo provides a source of NO that exerts beneficial effects upon the cardiovascular system, including reductions in inflammatory responses. We tested whether the antiinflammatory effects of inorganic nitrate might prove useful in ameliorating atherosclerotic disease in Apolipoprotein (Apo)E knockout (KO) mice. We show that dietary nitrate treatment, although having no effect upon total plaque area, caused a reduction in macrophage accumulation and an elevation in smooth muscle accumulation within atherosclerotic plaques of ApoE KO mice, suggesting plaque stabilization. We also show that in nitrate-fed mice there is reduced systemic leukocyte rolling and adherence, circulating neutrophil numbers, neutrophil CD11b expression, and myeloperoxidase activity compared with wild-type littermates. Moreover, we show in both the ApoE KO mice and using an acute model of inflammation that this effect upon neutrophils results in consequent reductions in inflammatory monocyte expression that is associated with elevations of the antiinflammatory cytokine interleukin (IL)-10. In summary, we demonstrate that inorganic nitrate suppresses acute and chronic inflammation by targeting neutrophil recruitment and that this effect, at least in part, results in consequent reductions in the inflammatory status of atheromatous plaque, and suggest that this effect may have clinical utility in the prophylaxis of inflammatory atherosclerotic disease. PMID:28057862

  7. 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.

  8. Mercuric oxide poisoning

    MedlinePlus

    ... oxide may be found in some: Button batteries (batteries containing mercury are no longer sold in the United States) Disinfectants Fungicides There have been reports of inorganic mercury poisoning from the use of skin-lightening creams. Note: This list may ...

  9. The biological inorganic chemistry of zinc ions.

    PubMed

    Krężel, Artur; Maret, Wolfgang

    2016-12-01

    The solution and complexation chemistry of zinc ions is the basis for zinc biology. In living organisms, zinc is redox-inert and has only one valence state: Zn(II). Its coordination environment in proteins is limited by oxygen, nitrogen, and sulfur donors from the side chains of a few amino acids. In an estimated 10% of all human proteins, zinc has a catalytic or structural function and remains bound during the lifetime of the protein. However, in other proteins zinc ions bind reversibly with dissociation and association rates commensurate with the requirements in regulation, transport, transfer, sensing, signalling, and storage. In contrast to the extensive knowledge about zinc proteins, the coordination chemistry of the "mobile" zinc ions in these processes, i.e. when not bound to proteins, is virtually unexplored and the mechanisms of ligand exchange are poorly understood. Knowledge of the biological inorganic chemistry of zinc ions is essential for understanding its cellular biology and for designing complexes that deliver zinc to proteins and chelating agents that remove zinc from proteins, for detecting zinc ion species by qualitative and quantitative analysis, and for proper planning and execution of experiments involving zinc ions and nanoparticles such as zinc oxide (ZnO). In most investigations, reference is made to zinc or Zn(2+) without full appreciation of how biological zinc ions are buffered and how the d-block cation Zn(2+) differs from s-block cations such as Ca(2+) with regard to significantly higher affinity for ligands, preference for the donor atoms of ligands, and coordination dynamics. Zinc needs to be tightly controlled. The interaction with low molecular weight ligands such as water and inorganic and organic anions is highly relevant to its biology but in contrast to its coordination in proteins has not been discussed in the biochemical literature. From the discussion in this article, it is becoming evident that zinc ion speciation is

  10. 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)...

  11. 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...

  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 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...

  15. 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...

  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, 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...

  18. 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...

  19. 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...

  20. 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...