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Sample records for acid sulfate solutions

  1. Surface chemistry of Cu(100) in acidic sulfate solutions

    NASA Astrophysics Data System (ADS)

    Ehlers, Charles B.; Stickney, John L.

    1990-12-01

    The surface chemistry of Cu(100), in H 2SO 4 and acidic K 2SO 4 solutions, has been studied by Auger electron spectroscopy (AES), low-energy electron diffraction (LEED) and thermal desorption spectroscopy (TDS). Experiments were conducted in an electrochemical cell coupled directly to a UHV surface analysis chamber. Structures formed on the Cu(100) surface emersed (removed) from sulfate solutions were the principal focus of this study. Structures and coverages were primarily dependent on sulfate concentration and the presence of coadsorbates such as Cl and K +. Emersion of Cu(100) from 1 mM H 2SO 4 resulted in a Cu(100)(2 × 2)-SO 2-4 adlattice with a {1}/{4} coverage of sulfate. A {1}/{5} coverage Cu(100)( 5 × 5) R26.6°- SO2-4 structure formed upon emersion mM H 2SO 4 containing trace Cl - contaminants, and a {1}/{3} coverage Cu(100)(2 × 100)- SO2-4 structure formed following e from 10 mM H 2SO 4. Emersion of Cu(100) from 1 mM K 2SO 4 (pH = 3.6) resulted in a Cu(100)(4 × 2 5)- SO2-4, K + surface structure, with K + and SO 2-4 coadsorbed in a 1:1 stoichiometry, each at {1}/{4} coverage. No significant potential-dependent variatio in surface structure or coverage was observed when the electrode was emersed from H 2SO 4 at potentials in the double-layer charging region. For emersion from 1 mM K 2SO 4 (pH = 3.6), a reduction in K + coverage along with a change in the surface structure to a (2 × 2) occurred at positive potentials. Comparisons were made of sulfate adsorption on the low-index planes of Cu using a Cu single crystal polished on three different faces to the (111), (110) and (100) planes. This electrode was emersed from 1 mM K 2SO 4 (pH = 3.6) at several potentials. A c(8 × 2) and a diffuse (1 × 1) LEED pattern were observed on Cu(110) and Cu(111), respectively. The K + and SO 2-4 coverages differed appreciably between the three surfaces. Significant differences were observed in the thermal desorption spectra of Cu(100) emersed from H 2SO 4 and K 2SO

  2. Improved process for the production of cellulose sulfate using sulfuric acid/ethanol solution.

    PubMed

    Chen, Guo; Zhang, Bin; Zhao, Jun; Chen, Hongwen

    2013-06-05

    An improved process for production of cellulose sulfate (CS) was developed by using sulfuric acid/ethanol solution as sulfonating agent and Na2SO4 as water absorbent. The FTIR, SEM and TG analysis were used to characterize the CS prepared. The total degree of substitution and viscosity of the product solution (2%, w/v) were ranging from 0.28 to 0.77 and from 115 to 907 mPa s, respectively, by changing the process parameters such as the amount of Na2SO4, the reaction time, the temperature, the sulfuric acid/alcohol ratio and liquid/solid ratio. The results indicated that the product with DS (0.28-0.77) and η2% (115-907) mPa s could be produced by using this improved process and more cellulose sulfate could be produced when cellulose was sulfonated for 3-4 h at -2 °C in sulfuric acid/ethanol (1.4-1.6) solution with addition of 0.8 g Na2SO4. The (13)C NMR indicated that the sulfate group of CS produced using sulfuric acid/ethanol solution was at C6 position.

  3. Copper-Sulfate Pentahydrate as a Product of the Waste Sulfuric Acid Solution Treatment

    NASA Astrophysics Data System (ADS)

    Marković, Radmila; Stevanović, Jasmina; Avramović, Ljiljana; Nedeljković, Dragutin; Jugović, Branimir; Stajić-Trošić, Jasna; Gvozdenović, Milica

    2012-12-01

    The aim of this study is synthesis of copper-sulfate pentahydrate from the waste sulfuric acid solution-mother liquor generated during the regeneration process of copper bleed solution. Copper is removed from the mother liquor solution in the process of the electrolytic treatment using the insoluble lead anodes alloyed with 6 mass pct of antimony on the industrial-scale equipment. As the result of the decopperization process, copper is removed in the form of the cathode sludge and is precipitated at the bottom of the electrolytic cell. By this procedure, the content of copper could be reduced to the 20 mass pct of the initial value. Chemical characterization of the sludge has shown that it contains about 90 mass pct of copper. During the decopperization process, the very strong poison, arsine, can be formed, and the process is in that case terminated. The copper leaching degree of 82 mass pct is obtained using H2SO4 aqueous solution with the oxygen addition during the cathode sludge chemical treatment at 80 °C ± 5 °C. Obtained copper salt satisfies the requirements of the Serbian Standard for Pesticide, SRPS H.P1. 058. Therefore, the treatment of waste sulfuric acid solutions is of great economic and environmental interest.

  4. Volatility of organic aerosol: evaporation of ammonium sulfate/succinic acid aqueous solution droplets.

    PubMed

    Yli-Juuti, Taina; Zardini, Alessandro A; Eriksson, Axel C; Hansen, Anne Maria K; Pagels, Joakim H; Swietlicki, Erik; Svenningsson, Birgitta; Glasius, Marianne; Worsnop, Douglas R; Riipinen, Ilona; Bilde, Merete

    2013-01-01

    Condensation and evaporation modify the properties and effects of atmospheric aerosol particles. We studied the evaporation of aqueous succinic acid and succinic acid/ammonium sulfate droplets to obtain insights on the effect of ammonium sulfate on the gas/particle partitioning of atmospheric organic acids. Droplet evaporation in a laminar flow tube was measured in a Tandem Differential Mobility Analyzer setup. A wide range of droplet compositions was investigated, and for some of the experiments the composition was tracked using an Aerosol Mass Spectrometer. The measured evaporation was compared to model predictions where the ammonium sulfate was assumed not to directly affect succinic acid evaporation. The model captured the evaporation rates for droplets with large organic content but overestimated the droplet size change when the molar concentration of succinic acid was similar to or lower than that of ammonium sulfate, suggesting that ammonium sulfate enhances the partitioning of dicarboxylic acids to aqueous particles more than currently expected from simple mixture thermodynamics. If extrapolated to the real atmosphere, these results imply enhanced partitioning of secondary organic compounds to particulate phase in environments dominated by inorganic aerosol.

  5. Acid Sulfate Alteration on Mars

    NASA Technical Reports Server (NTRS)

    Ming, D. W.; Morris, R. V.

    2016-01-01

    A variety of mineralogical and geochemical indicators for aqueous alteration on Mars have been identified by a combination of surface and orbital robotic missions, telescopic observations, characterization of Martian meteorites, and laboratory and terrestrial analog studies. Acid sulfate alteration has been identified at all three landing sites visited by NASA rover missions (Spirit, Opportunity, and Curiosity). Spirit landed in Gusev crater in 2004 and discovered Fe-sulfates and materials that have been extensively leached by acid sulfate solutions. Opportunity landing on the plains of Meridiani Planum also in 2004 where the rover encountered large abundances of jarosite and hematite in sedimentary rocks. Curiosity landed in Gale crater in 2012 and has characterized fluvial, deltaic, and lacustrine sediments. Jarosite and hematite were discovered in some of the lacustrine sediments. The high elemental abundance of sulfur in surface materials is obvious evidence that sulfate has played a major role in aqueous processes at all landing sites on Mars. The sulfate-rich outcrop at Meridiani Planum has an SO3 content of up to 25 wt.%. The interiors of rocks and outcrops on the Columbia Hills within Gusev crater have up to 8 wt.% SO3. Soils at both sites generally have between 5 to 14 wt.% SO3, and several soils in Gusev crater contain around 30 wt.% SO3. After normalization of major element compositions to a SO3-free basis, the bulk compositions of these materials are basaltic, with a few exceptions in Gusev crater and in lacustrine mudstones in Gale crater. These observations suggest that materials encountered by the rovers were derived from basaltic precursors by acid sulfate alteration under nearly isochemical conditions (i.e., minimal leaching). There are several cases, however, where acid sulfate alteration minerals (jarosite and hematite) formed in open hydrologic systems, e.g., in Gale crater lacustrine mudstones. Several hypotheses have been suggested for the

  6. Mechanism of electrochemical reduction of hydrogen peroxide on copper in acidic sulfate solutions.

    PubMed

    Stewart, Karen L; Gewirth, Andrew A

    2007-09-11

    Hydrogen peroxide is a commonly used oxidizer component in chemical mechanical planarization slurries, used in the processing of Cu metallization in microelectronics applications. We studied the electrochemical reduction of hydrogen peroxide on Cu in 0.1 M H2SO4 solutions using methods including cyclic voltammetry, rotating disk electrode experiments, surface-enhanced Raman spectroscopy, and density functional theory (DFT) calculations. The spectroscopy reveals that the hydrogen peroxide molecule is reduced at negative potentials to form a Cu-OH surface species in acidic solutions, a result consistent with the insight from Tafel slope measurements. DFT calculations support the instability of peroxide relative to the surface-coordinated hydroxide on both Cu(111) and Cu(100) surfaces.

  7. Study of the dose response of the system ferrous ammonium sulfate-sucrose-xylenol orange in acid aqueous solution

    NASA Astrophysics Data System (ADS)

    Juarez-Calderon, J. M.; Negron-Mendoza, A.; Ramos-Bernal, S.

    2014-11-01

    An aqueous solution of ammonium ferrous sulfate-sucrose-xylenol orange in sulfuric acid (FSX) is proposed as a dosimetric system for the processes of gamma irradiation in a range between 0.3 and 6 Gy. This system is based on the indirect oxidation of ferrous ion by an organic compound (sucrose) to ferric ion and on the formation of a color complex of Fe3+ in an acidic medium with xylenol orange (a dye). After gamma radiation, an observable change occurs in the color of the system. Irradiation was executed at three different temperatures (13 °C, 22 °C, and 40 °C). A spectrometric readout method at 585 nm was employed to evaluate the system's dose response. In all of the cases analyzed, the responses had a linear behavior, and a slight effect of irradiation temperature was observed. Post-irradiation response was also evaluated and showed the stability of the solutions 24 h after the irradiation. The results obtained suggest that FSX might be used as a dosimeter for low doses of gamma irradiation because it provides a stable signal, good reproducibility, and an accessible technique for analysis.

  8. Kinetics and mechanism of oxidation of chondroitin-4-sulfate polysaccharide by chromic acid in aqueous perchlorate solutions.

    PubMed

    Hassan, Refat; Ibrahim, Samia; Dahy, Abdel Rahman; Zaafarany, Ishaq; Tirkistani, Fahd; Takagi, Hideo

    2013-02-15

    The kinetics of chromic acid oxidation of chondroitin-4-sulfate polysaccharide as sulfated carbohydrates at a constant ionic strength of 4.0 mol dm(-3) has been investigated, spectrophotometrically. The reaction kinetics showed a first-order dependence in chromic acid and fractional-first-order kinetics with respect to the chondroitin-4-sulfate concentration. The influence of [H(+)] on the reaction rates showed that the oxidation process is acid-catalyzed. Added Mn(2+) ions indicated the formation of Cr(IV) as intermediate species. A kinetic evidence for formation of 1:1 intermediate complex was revealed. The kinetic parameters have been evaluated and a tentative reaction mechanism in good consistent with the kinetic results obtained is discussed.

  9. Laboratory Hydrothermal Alteration of Basaltic Tephra by Acid Sulfate Solutions: An Analog Process for Martian Weathering

    NASA Technical Reports Server (NTRS)

    Golden, D. C.; Ming, D. W.; Morris, R. V.

    2003-01-01

    The objective of this study is to conduct simulated Mars-like weathering experiments in the laboratory to determine the weathering products that might form during oxidative, acidic weathering of Mars analog materials.

  10. Solubilities and Glass Formation in Aqueous Solutions of the Sodium Salts of Malonic Acid With and Without Ammonium Sulfate.

    PubMed

    Kissinger, Jared A; Buttke, Lukas G; Vinokur, Anastasiya I; Guzei, Ilia A; Beyer, Keith D

    2016-06-02

    The solubility of sodium hydrogen malonate and sodium malonate in water both with and without ammonium sulfate present has been studied using differential scanning calorimetry and infrared spectroscopy. The crystals that form from sodium hydrogen malonate/water solutions were determined to be sodium hydrogen malonate monohydrate by single-crystal X-ray diffractometry. The crystals formed in sodium malonate/water solutions were determined to be sodium malonate monohydrate, a compound whose structure had not been previously known. When ammonium sulfate is added to these respective aqueous systems, the precipitation solids contain sodium sulfate decahydrate under low to moderate ammonium concentrations and lecontite (NaNH4SO4·2H2O) under high ammonium concentrations, which can be found under dry atmospheric conditions. Thus, it appears the presence of malonate and hydrogen malonate ions does not significantly affect the precipitation of inorganic salts in these systems. The glass transition temperatures of all solutions were also determined, and it was observed that the addition of ammonium sulfate slightly lowers the glass transition temperature in these solutions.

  11. Solid-solution partitioning and thionation of diphenylarsinic acid in a flooded soil under the impact of sulfate and iron reduction.

    PubMed

    Zhu, Meng; Tu, Chen; Hu, Xuefeng; Zhang, Haibo; Zhang, Lijuan; Wei, Jing; Li, Yuan; Luo, Yongming; Christie, Peter

    2016-11-01

    Diphenylarsinic acid (DPAA) is a major organic arsenic (As) compound derived from abandoned chemical weapons. The solid-solution partitioning and transformation of DPAA in flooded soils are poorly understood but are of great concern. The identification of the mechanisms responsible for the mobilization and transformation of DPAA may help to develop effective remediation strategies. Here, soil and Fe mineral incubation experiments were carried out to elucidate the partitioning and transformation of DPAA in anoxic (without addition of sulfate or sodium lactate) and sulfide (with the addition of sulfate and sodium lactate) soil and to examine the impact of sulfate and Fe(III) reduction on these processes. Results show that DPAA was more effectively mobilized and thionated in sulfide soil than in anoxic soil. At the initial incubation stages (0-4weeks), 6.7-74.5% of the total DPAA in sulfide soil was mobilized likely by sorption competition with sodium lactate. At later incubation stage (4-8weeks), DPAA was almost completely released into the solution likely due to the near-complete Fe(III) reduction. Scanning transmission X-ray microscopy (STXM) results provide further direct evidence of elevated DPAA release coupled with Fe(III) reduction in sulfide environments. The total DPAA fraction decreased significantly to 24.5% after two weeks and reached 3.4% after eight weeks in sulfide soil, whereas no obvious elimination of DPAA occurred in anoxic soil at the initial two weeks and the total DPAA fraction decreased to 10.9% after eight weeks. This can be explained in part by the enhanced mobilization of DPAA and sulfate reduction in sulfide soil compared with anoxic soil. These results suggest that under flooded soil conditions, Fe(III) and sulfate reduction significantly promote DPAA mobilization and thionation, respectively, and we suggest that it is essential to consider both sulfate and Fe(III) reduction to further our understanding of the environmental fate of DPAA.

  12. High resolution electrochemical STM : new structural results for underpotentially deposited Cu on Au(111) in acid sulfate solution.

    SciTech Connect

    Sieradzki, Karl; Vasiljevic, Natasa; Viyannalage, L.K.T.; Dimitrov, Nikolay

    2007-09-01

    Adsorption of sulfate assists Cu monolayer underpotential deposition (upd) on Au(111) in a unique way, rendering two distinct structural stages: (i) formation of a low-density Cu phase at coverage of 2/3 ML known as the ({radical}3 x {radical}3) R30{sup o} or honeycomb phase; (ii) formation of a complete monolayer, i.e., Cu-(1 x 1) phase pseudomorphic with respect to underlying Au(111) substrate. In this paper we present new structural in situ scanning tunneling microscopy (STM) results for this system. We show and discuss the STM imaging of the copper honeycomb superstructure probed underneath the co-adsorbed ({radical}3 x {radical}3)R30{sup o} sulfate adlayer in the low-density phase. High resolution imaging during the phase transition from the low to high density copper phase unambiguously shows the existence of an ordered sulfate structure p(2 x 2) on the pseudomorphic Cu-(1 x 1) layer. The new structure is seen during the co-existence of two copper phases as well as upon completion of the Cu-(1 x 1) monolayer. While supported by earlier chronocoulometric measurements in the same system, the new structural results raise questions that need to be addressed in a future work.

  13. 21 CFR 522.1484 - Neomycin sulfate sterile solution.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Neomycin sulfate sterile solution. 522.1484... § 522.1484 Neomycin sulfate sterile solution. (a) Specifications. Each milliliter of sterile aqueous solution contains 50 milligrams of neomycin sulfate (equivalent to 35 milligrams of neomycin base).1...

  14. 21 CFR 522.1484 - Neomycin sulfate sterile solution.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Neomycin sulfate sterile solution. 522.1484... § 522.1484 Neomycin sulfate sterile solution. (a) Specifications. Each milliliter of sterile aqueous solution contains 50 milligrams of neomycin sulfate (equivalent to 35 milligrams of neomycin base).1...

  15. 21 CFR 522.1484 - Neomycin sulfate sterile solution.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Neomycin sulfate sterile solution. 522.1484... § 522.1484 Neomycin sulfate sterile solution. (a) Specifications. Each milliliter of sterile aqueous solution contains 50 milligrams of neomycin sulfate (equivalent to 35 milligrams of neomycin base).1...

  16. 21 CFR 522.1484 - Neomycin sulfate sterile solution.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Neomycin sulfate sterile solution. 522.1484... § 522.1484 Neomycin sulfate sterile solution. (a) Specifications. Each milliliter of sterile aqueous solution contains 50 milligrams of neomycin sulfate (equivalent to 35 milligrams of neomycin base).1...

  17. Acidic Fluids Across Mars: Detections of Magnesium-Nickel Sulfates

    NASA Technical Reports Server (NTRS)

    Yen, A. S.; Ming, D. W.; Gellert, R.; Mittlefehldt, D. W.; Rampe, E. B.; Vaniman, D. T.; Thompson, L. M.; Morris, R. V.; Clark, B. C.; VanBommel, S. J.

    2017-01-01

    Calcium, magnesium and ferric iron sulfates have been detected by the instrument suites on the Mars rovers. A subset of the magnesium sulfates show clear associations with nickel. These associations indicate Ni(2+) co-precipitation with or substitution for Mg(2+) from sulfate-saturated solutions. Nickel is ex-tracted from primary rocks almost exclusively at pH values less than 6, constraining the formation of these Mg-Ni sulfates to mildly to strongly acidic conditions. There is clear evidence for aqueous alteration at the rim of Endeavour Crater (Meridiani Planum), in the Murray formation mudstone (Gale Crater), and near Home Plate (Gusev Crater). The discovery of Mg-Ni sulfates at these locations indicates a history of fluid-rock interactions at low pH.

  18. Electrochemical corrosion and modeling studies of types 7075 and 2219 aluminum alloys in a nitric acid + ferric sulfate deoxidizer solution

    NASA Astrophysics Data System (ADS)

    Savas, Terence P.

    The corrosion behavior of types 7075-T73 and 2219-T852 high strength aluminum alloys have been investigated in a HNO3 + Fe2(SO 4)3 solution. The materials are characterized in the time domain using the electrochemical noise resistance parameter (Rn) and in the frequency-domain using the spectral noise impedance parameter ( Rsn). The Rsn parameter is derived from an equivalent electrical circuit model that represents the corrosion test cell schematic used in the present study. These calculated parameters are correlated to each other, and to corresponding scanning electron microscopy (SEM) examinations of the corroded surfaces. In addition, energy dispersive spectroscopy (EDS) spectra are used in conjunction with SEM exams for particle mapping and identification. These constituent particles are characterized with respect to their size and composition and their effect on the localized corrosion mechanisms taking place. Pitting mechanisms are identified as 'circumferential' where the particles appeared noble with respect to the aluminum matrix and by 'selective dissolution' where they are anodic to the aluminum matrix. The electrochemical data are found to be in good agreement with the surface examinations. Specifically, the electrochemical parameters Rn and Rsn were consistent in predicting the corrosion resistance of 7075-T73 to be lower than for the 2219-T852 alloy. Other characteristic features used in understanding the corrosion mechanisms include the open circuit potential (OCP) and coupling-current time records.

  19. METHOD OF INHIBITING CORROSION IN URANYL SULFATE SOLUTIONS

    DOEpatents

    Bohlmann, E.G.; Griess, J.C. Jr.

    1960-08-23

    A method is given for treating a uranyl sulfate solution to inhibit the corrosiveness of the solution and elevate the phase separation temperature of the solution. Lithium sulfate is added to the solution in an amount ranging from 0.25 to 1.3 times the uranyl sulfate concentration. The corrosiveness of the solution with respect to stainless steel is substantially decreased by this means. This treatment also serves to raise the phase separation temperature of the solution (above 250 deg C), at which time the uranyl sulfate solution separates into two liquid phases of unequal uranium concentration and thus becomes unsuitable as nuclear reactor fuel.

  20. Effect of dosing sequence and solution pH on floc properties of the compound bioflocculant-aluminum sulfate dual-coagulant in kaolin-humic acid solution treatment.

    PubMed

    Bo, Xiaowen; Gao, Baoyu; Peng, Nana; Wang, Yan; Yue, Qinyan; Zhao, Yingcan

    2012-06-01

    The compound bioflocculant (CBF)-aluminum sulfate (AS) dual-coagulant and AS were comparatively studied for the coagulation of kaolin-humic acid solution. Floc properties including floc growth rate, size, strength, recoverability and fractal dimension under different pH conditions were investigated by Mastersizer 2000. Results indicated that, the flocs formed by AS-CBF (AS dosed first) showed the largest size and the best recoverability across the pH range investigated. While flocs formed by CBF-AS gave the most compact structure. The three coagulants exhibited similar floc growth rate and strength. Moreover, flocs formed in acidic conditions were stronger and more recoverable but showed lower growth rate, smaller size and looser structure compared to those formed at pH>6 regardless of the coagulant used. Charge neutralization was the dominant mechanism for AS at low pH, while the coagulation mechanism transformed to enmeshment as the pH increased. There was an additional adsorption bridging effect for AS-CBF and CBF-AS.

  1. 21 CFR 529.50 - Amikacin sulfate intrauterine solution.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Amikacin sulfate intrauterine solution. 529.50 Section 529.50 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Amikacin sulfate intrauterine solution. (a) Specifications. Each milliliter of sterile aqueous...

  2. Sulfate and acid resistant concrete and mortar

    DOEpatents

    Liskowitz, J.W.; Wecharatana, M.; Jaturapitakkul, C.; Cerkanowicz, A.E.

    1998-06-30

    The present invention relates to concrete, mortar and other hardenable mixtures comprising cement and fly ash for use in construction and other applications, which hardenable mixtures demonstrate significant levels of acid and sulfate resistance while maintaining acceptable compressive strength properties. The acid and sulfate hardenable mixtures of the invention containing fly ash comprise cementitious materials and a fine aggregate. The cementitous materials may comprise fly ash as well as cement. The fine aggregate may comprise fly ash as well as sand. The total amount of fly ash in the hardenable mixture ranges from about 60% to about 120% of the total amount of cement, by weight, whether the fly ash is included as a cementious material, fine aggregate, or an additive, or any combination of the foregoing. In specific examples, mortar containing 50% fly ash and 50% cement in cementitious materials demonstrated superior properties of corrosion resistance. 6 figs.

  3. Sulfate and acid resistant concrete and mortar

    DOEpatents

    Liskowitz, John W.; Wecharatana, Methi; Jaturapitakkul, Chai; Cerkanowicz, deceased, Anthony E.

    1998-01-01

    The present invention relates to concrete, mortar and other hardenable mixtures comprising cement and fly ash for use in construction and other applications, which hardenable mixtures demonstrate significant levels of acid and sulfate resistance while maintaining acceptable compressive strength properties. The acid and sulfate hardenable mixtures of the invention containing fly ash comprise cementitious materials and a fine aggregate. The cementitous materials may comprise fly ash as well as cement. The fine aggregate may comprise fly ash as well as sand. The total amount of fly ash in the hardenable mixture ranges from about 60% to about 120% of the total amount of cement, by weight, whether the fly ash is included as a cementious material, fine aggregate, or an additive, or any combination of the foregoing. In specific examples, mortar containing 50% fly ash and 50% cement in cementitious materials demonstrated superior properties of corrosion resistance.

  4. Simulation of Natural Acid Sulfate Weathering in an Alpine Watershed

    NASA Astrophysics Data System (ADS)

    Bassett, R. L.; Miller, William R.; McHugh, John; Catts, John G.

    1992-09-01

    Streams with acidic sulfate compositions (pH less than 3.5) are naturally generated in the alpine Geneva Creek Basin of the southern Rocky Mountains, an area underlain by Proterozoic metamorphic and igneous rocks that are intruded by Tertiary felsic stocks with associated pyritic alteration. These naturally acidic waters are similar in composition to more familiar man-made acid mine waters or to surface waters acidified by sulfate precipitation. Detailed study of the stream compositions has revealed the principal reactions driving the weathering process and was used to estimate the relative effects of snowpack ionic input versus the solute contribution from acid attack in soil zones and groundwater. In the Geneva Creek Basin, atmospheric sources of solute represent a minor component to the stream water composition, except for chloride, which can be used to determine the fraction of contribution. The weathering process is a balance between oxidation of sulfides, dissolution of silicates, formation of the clay minerals vermiculite, kaolinite, and smectite, carbonate neutralization, and precipitation of ferric and aluminum oxyhydroxides and aluminum sulfate. The chemical analyses of snow samples, multiple samples of water from Geneva Creek and its tributaries, and the composition of primary and secondary minerals identified in the basin serve as input to a mass balance geochemical model, which facilitates the interpretation of the principal geochemical processes.

  5. 21 CFR 524.1484e - Neomycin sulfate and polymyxin B sulfate ophthalmic solution.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS OPHTHALMIC AND TOPICAL DOSAGE FORM NEW ANIMAL DRUGS § 524.1484e Neomycin sulfate and polymyxin B sulfate ophthalmic solution. (a... nonsusceptible to the antibiotics incorporated in the drug. (4) Federal law restricts this drug to use by or...

  6. Recovery of discarded sulfated lead-acid batteries

    NASA Astrophysics Data System (ADS)

    Karami, Hassan; Asadi, Raziyeh

    The aim of this research is to recover discarded sulfated lead-acid batteries. In this work, the effect of two methods (inverse charge and chemical charge) on the reactivation of sulfated active materials was investigated. At the inverse charge, the battery is deeply discharged and the electrolyte of battery is replaced with a new sulfuric acid solution of 1.28 g cm -3. Then, the battery is inversely charged with constant current method (2 A for the battery with the nominal capacity of 40 Ah) for 24 h. At the final stage, the inversely charged battery is directly charged for 48 h. Through these processes, a discarded battery can recover its capacity to more than 80% of a similar fresh and non-sulfated battery. At the chemical charge method, there are some effective parameters that including ammonium persulfate [(NH 4) 2S 2O 8] concentration, recovery temperature and recovery time. The effect of all parameters was optimized by one at a time method. The sulfated battery is deeply discharged and then, its electrolyte was replaced by a 40% ammonium persulfate solution (as oxidant) at temperature of 50 °C. By adding of oxidant solution, the chemical charging of positive and negative plates was performed for optimum time of 1 h. The chemically charged batteries were charged with constant voltage method (2.66 V for the battery with nominal voltage and nominal capacity of 2 V and 10 Ah, respectively) for 24 h. By performing of these processes, a discarded battery can recovers its capacity to more than 84% of the similar fresh and non-sulfated battery. Discharge and cyclelife behaviors of the recovered batteries were investigated and compared with similar healthy battery. The morphology and structure of plates was studied by scanning electron microscopy (SEM) before and after recovery.

  7. Determination of trace elements in triglycine sulfate solutions

    NASA Technical Reports Server (NTRS)

    Tadros, Shawky H.

    1993-01-01

    Ten elements were divided into 2 groups. The elements in the first group included iron, nickel, chromium, manganese, copper, and gold. The elements in the second group included zinc, cobalt, lead, cadmium, and gold. Five ppm of each element in each group was spiked in a 1 percent triglycine sulfate (TGS) solution. Glycine was removed with 1-naphthyl isocyanate in ether medium. The glycine derivative 1-naphthyl isocyanate glycine was removed by filtration, and the filtrates were analyzed for the different elements. Analysis of these elements was performed by using the 5100 Perkin-Elmer Atomic Absorption Spectrophotometer. The result of these experiments was the observation that there was a decrease in the concentration of chromium and gold, which was interpreted to be due to the chelation of these elements by the derivative 1-naphthyl isocyanate glycine. Further research is needed to determine the concentration of other elements in triglycine sulfate (TGS) solutions. These elements will include lithium, sodium, rubidium, magnesium, calcium, strontium, barium, aluminum, and silicon. These are the most likely elements to be found in the sulfuric acid used in manufacturing the TGS crystal. Moreover, we will extend our research to investigate the structural formula of the violet colored chelated compounds, which had been formed by interaction of the derivative 1-naphthyl isocyanate glycine with the different elements, such as gold, chromium.

  8. On the evaporation of ammonium sulfate solution

    SciTech Connect

    Drisdell, Walter S.; Saykally, Richard J.; Cohen, Ronald C.

    2009-07-16

    Aqueous evaporation and condensation kinetics are poorly understood, and uncertainties in their rates affect predictions of cloud behavior and therefore climate. We measured the cooling rate of 3 M ammonium sulfate droplets undergoing free evaporation via Raman thermometry. Analysis of the measurements yields a value of 0.58 {+-} 0.05 for the evaporation coefficient, identical to that previously determined for pure water. These results imply that subsaturated aqueous ammonium sulfate, which is the most abundant inorganic component of atmospheric aerosol, does not affect the vapor-liquid exchange mechanism for cloud droplets, despite reducing the saturation vapor pressure of water significantly.

  9. Acid Sulfate Alteration in Gusev Crater, Mars

    NASA Technical Reports Server (NTRS)

    Morris, R. V.; Ming, D. W.; Catalano, J. G.

    2016-01-01

    dust. The Moessbauer parameters are not definitive for mineralogical speciation (other than octahedrally-coordinated Fe(3+) but are consistent with a schwertmannite-like phase (i.e., a nanophase ferric oxide). The high oxidation state and values of Moessbauer parameters (center shift and quadrupole splitting) for the high-SO3 samples imply ferric sulfate (i.e., oxidized sulfur), although the hydration state cannot be constrained. In no case is there an excess of SO3 over available cations (i.e., no evidence for elemental sulfur), and Fe sulfide (pyrite) has been detected in only one Gusev sample. The presence of both high-SiO2 (and low total iron and SO3) and high SO3 (and high total iron as ferric sulfate) can be accommodated by a two-step geochemical model developed with the Geochemist's Workbench. (1) Step 1 is anoxic acid sulfate leaching of Martian basalt at high water-to rock ratios (greater than 70). The result is a high-SiO2 residue0, and anoxic conditions are required to solubilize Fe as Fe(2+). (2) Step 2 is the oxic precipitation of sulfate salts from the leachate. Oxic conditions are required to produce the high concentrations of ferric sulfate with minor Mg-sulfates and no detectable Fe(2+)-sulfates.

  10. Diffusion of triglycine sulfate in aqueous solution

    NASA Technical Reports Server (NTRS)

    Kroes, R. L.; Reiss, D.; Silberman, E.; Morgan, S.

    1985-01-01

    The diffusion coefficient of triglycine sulfate (TGS) in water was measured for several concentrations over a temperature range of 25 to 55 C. The activation energy for diffusion obtained from these measurements was 4180 cal/mol. No concentration dependence was seen. The maximum difference in D for the various ionic species present was determined by Raman spectroscopy to be about 5 percent.

  11. Electrochemical treatment of acidic aqueous ferrous sulfate and copper sulfate as models for acid mine drainage.

    PubMed

    Bunce, N J; Chartrand, M; Keech, P

    2001-12-01

    Acid mine drainage (AMD) is a serious environmental problem in the mining industry. The present work describes electrolytic reduction of solutions of synthetic AMD, comprising FeSO4/H2SO4 and CuSO4/H2SO4, in flow-through cells whose anode and cathode compartments were separated using ion exchange membranes. In the case of FeSO4/H2SO4 at constant flow rate, the pH of the effluent from the catholyte increased progressively with current at a variety of cathodes, due to electrolytic reduction of H+ ions to elemental hydrogen. Near-quantitative removal of iron was achieved by sparging air into the catholyte effluent, thereby precipitating iron outside the electrochemical cell, and avoiding fouling of the electrodes. The anode reaction was the oxidation of water to O2, a proton-releasing process. Using cation exchange membranes and sodium sulfate as the supporting electrolyte in the anode compartment, the efficiency of the process was compromised at high currents by transport of H+ competitively with Na+ from the anode to the cathode compartments. Higher efficiencies were obtained when anion exchange membranes were used, and in this case no additional supporting electrolyte other than dilute H2SO4 was needed, the net reaction being the electrochemically driven transfer of the elements of H2SO4 from the cathode to the anode compartments. Current efficiencies approximately 50% were achieved, the loss of efficiency being accounted for by ohmic heating of the solutions. In the case of CuSO4/H2SO4 and anion exchange membranes at high currents, reduction of Cu2+ and H+ ions and transport of SO4(2-) ions out of the catholyte caused unacceptably high potentials to be generated.

  12. ZnO Solubility and Zn 2 Complexation by Chloride and Sulfate in Acidic Solutions to 290°C with In-Situ pH Measurement

    NASA Astrophysics Data System (ADS)

    Wesolowski, David J.; Bénézeth, Pascale; Palmer, Donald A.

    1998-03-01

    The solubility of zincite in mildly to strongly acidic aqueous solutions, according to the reaction ZnO + 2H + ⇔ Zn 2+ + H 2O, has been measured at ionic strengths of 0.03-1.0 (stoichiometric molal basis) from 50 to 290°C at saturation vapor pressure in sodium trifluoromethanesulfonate solutions (NaTriflate, a noncomplexing 1:1 electrolyte). The hydrogen-electrode concentration cells employed in this study permit continuous and highly accurate pH measurement at elevated temperatures, and periodic sampling to determine the dissolved metal content of the experimental solution. The solubility of zincite is shown to be reversible at 200°C by addition of acidic and basic titrants, at constant ionic strength. The equilibrium constant is precisely described (±0.05 log units) by the function log K = -4.0168 + 4527.66/T. One additional adjustable parameter, together with an extended Debye-Hückel function, is sufficient to model the ionic strength dependence of the reaction. The solubility product at infinite dilution obtained from this study is in quantitative agreement with the thermodynamic model of Ziemniak 1992. This experimental approach is demonstrated to be advantageous in studying the complexation of Zn 2+ with Cl - and SO 42-, by titrations involving the appropriate anion into NaTriflate solutions pre-equilibrated with zincite at constant temperature and ionic strength. Formation constants in 0.1 molal NaTriflate for the reaction Zn 2+ + yL z- ⇔ Zn(L) y2-yz are reported for ZnCl +, ZnCl 2° and ZnSO 4° at 200°C (log Q = 1.7 ± 0.1, 3.0 ± 0.1, and 2.6 ± 0.1, respectively). Estimates of the equilibrium constants for the chloride species at infinite dilution and 200°C are log K = 2.5 ± 0.1 (ZnCl +), and 4.2 ± 0.1 (ZnCl 2°). This value for the dichlorozinc complex agrees quantitatively with values reported by Bourcier and Barnes 1987 and Ruaya and Seward 1986. However, the latter authors give a value for the monochlorozinc complex (log K = 4.01 ± 0

  13. Effects of raised temperature of sulfate solutions on the sulfate resistance of mortars with and without silica fume

    SciTech Connect

    Akoez, F.; Koral, S.; Yuezer, N.; Tuerker, F.

    1999-04-01

    Effect of raised temperature of sodium sulfate and magnesium sulfate solutions on the resistance of mortars was investigated. Experimental study was carried out on mortars with and without silica fume. Sulfate concentration was 18,000 mg/L as SO{sub 4}{sup 2{minus}} for the sodium sulfate and 13,000 mg/L magnesium sulfate solutions. Temperatures of solutions were 20 and 40 C. Some physical and mechanical properties were tested during the 300 days of sulfate exposure. Test results showed that raised solution temperature did not accelerate the deterioration of mortars under the conditions used in this research. Moreover, raised temperature improved many properties of the specimens. It can be suggested that there are some problems with raising the temperature of sulfate solution as an accelerated test method.

  14. Biological functions of iduronic acid in chondroitin/dermatan sulfate.

    PubMed

    Thelin, Martin A; Bartolini, Barbara; Axelsson, Jakob; Gustafsson, Renata; Tykesson, Emil; Pera, Edgar; Oldberg, Åke; Maccarana, Marco; Malmstrom, Anders

    2013-05-01

    The presence of iduronic acid in chondroitin/dermatan sulfate changes the properties of the polysaccharides because it generates a more flexible chain with increased binding potentials. Iduronic acid in chondroitin/dermatan sulfate influences multiple cellular properties, such as migration, proliferation, differentiation, angiogenesis and the regulation of cytokine/growth factor activities. Under pathological conditions such as wound healing, inflammation and cancer, iduronic acid has diverse regulatory functions. Iduronic acid is formed by two epimerases (i.e. dermatan sulfate epimerase 1 and 2) that have different tissue distribution and properties. The role of iduronic acid in chondroitin/dermatan sulfate is highlighted by the vast changes in connective tissue features in patients with a new type of Ehler-Danlos syndrome: adducted thumb-clubfoot syndrome. Future research aims to understand the roles of the two epimerases and their interplay with the sulfotransferases involved in chondroitin sulfate/dermatan sulfate biosynthesis. Furthermore, a better definition of chondroitin/dermatan sulfate functions using different knockout models is needed. In this review, we focus on the two enzymes responsible for iduronic acid formation, as well as the role of iduronic acid in health and disease.

  15. Sulfate Mineral Formation from Acid-weathered Phyllosilicates: Implications for the Aqueous History of Mars

    NASA Astrophysics Data System (ADS)

    Craig, Patricia; Ming, Douglas; Rampe, Elizabeth

    2014-11-01

    Phyllosilicates on Mars are common in Noachian terrains whereas sulfates are found in the younger Hesperian terrains and suggest alteration under more acidic conditions. Phyllosilicates that formed during the Noachian era would have been exposed to the prevailing acidic conditions during the Hesperian. The purpose of this project is to characterize the effects of acid-weathering on phyllosilicates to better understand the aqueous history of Mars. Nontronite, montmorillonite, and saponite were exposed to H2SO4 solutions at water-rock (WR) ratios of 50 and 25.X-ray diffraction (XRD) patterns of all three acid-treated minerals showed progressive collapse of the phyllosilicate basal spacing with increasing acid concentration. Bassanite formed as an intermediate phase in weathered nontronite and montmorillonite from extracted interlayer Ca. The octahedral cation determined which sulfate formed at high acid concentration: rhomboclase from nontronite, alunogen from montmorillonite, hexahydrite and kieserite from saponite. Gypsum and anhydrite also formed as intermediate phases in nontronite treated at WR=25, showing a change in sulfate hydration state with changing acid concentration (i.e. water activity). Scanning electron microscopy analyses detected phases not identified by XRD. Al-sulfate was found in nontronite weathered at WR=25 and Ca-sulfate in weathered saponite. Near-infrared reflectance spectra of the weathered samples showed decreasing intensity of the hydration/hydroxylation bands and a change or disappearance of metal-OH bands indicating dehydration and dissociation of the interlayers and octahedral layers, respectively, with increased acid weathering.Sulfate mineral formation from acid-weathered phyllosilicates may explain the presence of phyllosilicates and sulfates in close proximity to each other on Mars, such as in Gale Crater. The CheMin XRD instrument on Curiosity may find evidence for acid-weathered phyllosilicates in Mt. Sharp by comparing the 001

  16. Acidity characterization of a titanium and sulfate modified vermiculite

    SciTech Connect

    Hernandez, W.Y.; Centeno, M.A.; Odriozola, J.A.; Moreno, S.; Molina, R.

    2008-07-01

    A natural vermiculite has been modified with titanium and sulfated by the intercalation and impregnation method in order to optimize the acidity of the clay mineral, and characterization of samples were analyzed by X-ray fluorescence (XRF), X-ray diffraction (XRD), nitrogen adsorption isotherms, diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and temperature programmed desorption with ammonia (TPD-NH{sub 3}). All the modified solids have a significantly higher number of acidic sites with respect to the parent material and in all of these, Broensted as well as Lewis acidity are identified. The presence of sulfate appears not to increase the number of acidic centers in the modified clay. For the materials sulfated with the intercalation method, it is observed that the strength of the acidic sites found in the material increases with the nominal sulfate/metal ratio. Nevertheless, when elevated quantities of sulfur are deposited, diffusion problems in the heptane reaction appear.

  17. Solute-solvent interactions in micellar electrokinetic chromatography. Selectivity of lithium dodecyl sulfate-lithium perfluorooctanesulfonate mixed-micellar buffers.

    PubMed

    Fuguet, E; Ràfols, C; Bosch, E; Rosés, M; Abraham, M H

    2001-01-12

    The solvation parameter model has been applied to the characterization of micellar electrokinetic chromatographic (MEKC) systems with mixtures of lithium dodecyl sulfate and lithium perfluorooctanesulfonate as surfactant. The variation in MEKC surfactant composition results in changes in the coefficients of the correlation equation, which in turns leads to information on solute-solvent and solute-micelle interactions. Lithium perfluorooctanesulfonate is more dipolar and hydrogen bond acidic but less polarizable and hydrogen bond basic than lithium dodecyl sulfate. Therefore mixtures of lithium dodecyl sulfate and lithium perfluorooctanesulfonate cover a very wide range of polarity and hydrogen bond properties, which in turn results in important selectivity changes for analytes with different solute properties.

  18. The effect of divalent salt in chondroitin sulfate solutions

    NASA Astrophysics Data System (ADS)

    Aranghel, D.; Badita, C. R.; Radulescu, A.; Moldovan, L.; Craciunescu, O.; Balasoiu, M.

    2016-03-01

    Chondroitin-4 sulfate (CS4) is the main glycosaminoglycan extracted from bovine trachea. CS4 play an important role in osteoarthritis treatment, anticoagulant activity, reduces the degradation of cartilage matrix components, reduces necrosis and apoptosis of chondrocytes and reduces the activity of collagenase. Chondroitin sulfate is also responsible for proteoglycans degradation. Chondroitin sulfate can bind calcium ions with different affinities, depending on their sulfation position. The purpose of this study was to determine the structural properties and the influence of Ca2+ cations. We carried out measurements on CS4 solutions and mixtures of liquid CS4 with Ca2+ by Small-Angle Neutron Scattering (SANS). CS4 have a mass fractal behavior and the addition of a salt (CaCl2) in CS4 solutions generates the appearance of a correlation peak due to local ordering between adjacent chains with inter-chain distances between 483 Å and 233 Å for a calcium concentration of 0.01% w/w.

  19. Study of the solubility of petroleum sulfoxides and their extraction from sulfate and fluoride-sulfate solutions

    SciTech Connect

    Nikolaev, A.I.; Zalkind, L.M.; Babkin, A.G.; Kasikova, N.I.; Toropov, Y.A.

    1983-02-20

    Study of the influence of the ammonium sulfate and sulfuric and hydrochloric acid concentrations and of temperature on the solubility of petroleum sulfoxides in aqueous solutions showed that the solubility of petroleum sulfoxides is in the range 0.1-2.1 g/liter. The solubility of petroleum sulfoxides under conditions of extraction of metals from fluoride-sulfate solutions was determined with the aid of factorial experimental design. The initial and constant solubilities of petroleum sulfoxides were determined. Washing of the sulfoxides with a 600-fold volume of 1.0 M H/sub 2/SO/sub 4/ solution lowers the solubility of petroleum sulfoxides from 1.26-1.02 to 0.12-0.10 g/liter. The conditions for extraction of PSO from aqueous solutions by kerosine were found, and it was shown that under these conditions the extraction of sulfoxides into kerosine reaches 85% in a single stage and more than 96% in three stages.

  20. Electrochemical Deposition and Dissolution of Thallium from Sulfate Solutions

    PubMed Central

    Ussipbekova, Ye. Zh.; Seilkhanova, G. A.; Jeyabharathi, Ch.; Scholz, F.; Kurbatov, A. P.; Nauryzbaev, M. K.; Berezovskiy, A.

    2015-01-01

    The electrochemical behavior of thallium was studied on glassy carbon electrodes in sulfate solutions. Cyclic voltammetry was used to study the kinetics of the electrode processes and to determine the nature of the limiting step of the cathodic reduction of thallium ions. According to the dependence of current on stirring rate and scan rate, this process is diffusion limited. Chronocoulometry showed that the electrodeposition can be performed with a current efficiency of up to 96% in the absence of oxygen. PMID:26064120

  1. 21 CFR 864.9320 - Copper sulfate solution for specific gravity determinations.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Copper sulfate solution for specific gravity... Establishments That Manufacture Blood and Blood Products § 864.9320 Copper sulfate solution for specific gravity determinations. (a) Identification. A copper sulfate solution for specific gravity determinations is a...

  2. 21 CFR 864.9320 - Copper sulfate solution for specific gravity determinations.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Copper sulfate solution for specific gravity... Establishments That Manufacture Blood and Blood Products § 864.9320 Copper sulfate solution for specific gravity determinations. (a) Identification. A copper sulfate solution for specific gravity determinations is a...

  3. 21 CFR 864.9320 - Copper sulfate solution for specific gravity determinations.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Copper sulfate solution for specific gravity... Establishments That Manufacture Blood and Blood Products § 864.9320 Copper sulfate solution for specific gravity determinations. (a) Identification. A copper sulfate solution for specific gravity determinations is a...

  4. 21 CFR 864.9320 - Copper sulfate solution for specific gravity determinations.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Copper sulfate solution for specific gravity... Establishments That Manufacture Blood and Blood Products § 864.9320 Copper sulfate solution for specific gravity determinations. (a) Identification. A copper sulfate solution for specific gravity determinations is a...

  5. 21 CFR 864.9320 - Copper sulfate solution for specific gravity determinations.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Copper sulfate solution for specific gravity... Establishments That Manufacture Blood and Blood Products § 864.9320 Copper sulfate solution for specific gravity determinations. (a) Identification. A copper sulfate solution for specific gravity determinations is a...

  6. Impact of mitigation strategies on acid sulfate soil chemistry and microbial community.

    PubMed

    Wu, Xiaofen; Sten, Pekka; Engblom, Sten; Nowak, Pawel; Österholm, Peter; Dopson, Mark

    2015-09-01

    Potential acid sulfate soils contain reduced iron sulfides that if oxidized, can cause significant environmental damage by releasing large amounts of acid and metals. This study examines metal and acid release as well as the microbial community capable of catalyzing metal sulfide oxidation after treating acid sulfate soil with calcium carbonate (CaCO3) or calcium hydroxide (Ca(OH)2). Leaching tests of acid sulfate soil samples were carried out in the laboratory. The pH of the leachate during the initial flushing with water lay between 3.8 and 4.4 suggesting that the jarosite/schwertmannite equilibrium controls the solution chemistry. However, the pH increased to circa 6 after treatment with CaCO3 suspension and circa 12 after introducing Ca(OH)2 solution. 16S rRNA gene sequences amplified from community DNA extracted from the untreated and both CaCO3 and Ca(OH)2 treated acid sulfate soils were most similar to bacteria (69.1% to 85.7%) and archaea (95.4% to 100%) previously identified from acid and metal contaminated environments. These species included a Thiomonas cuprina-like and an Acidocella-like bacteria as well as a Ferroplasma acidiphilum-like archeon. Although the CaCO3 and Ca(OH)2 treatments did not decrease the proportion of microorganisms capable of accelerating acid and metal release, the chemical effects of the treatments suggested their reduced activity.

  7. Acid Sulfate Weathering on Mars: Results from the Mars Exploration Rover Mission

    NASA Technical Reports Server (NTRS)

    Ming, Douglas W.; Morris, R. V.; Golden, D. C.

    2006-01-01

    Sulfur has played a major role in the formation and alteration of outcrops, rocks, and soils at the Mars Exploration Rover landing sites on Meridiani Planum and in Gusev crater. Jarosite, hematite, and evaporite sulfates (e.g., Mg and Ca sulfates) occur along with siliciclastic sediments in outcrops at Meridiani Planum. The occurrence of jarosite is a strong indicator for an acid sulfate weathering environment at Meridiani Planum. Some outcrops and rocks in the Columbia Hills in Gusev crater appear to be extensively altered as suggested by their relative softness as compared to crater floor basalts, high Fe(3+)/FeT, iron mineralogy dominated by nanophase Fe(3+) oxides, hematite and/or goethite, corundum-normative mineralogies, and the presence of Mg- and Casulfates. One scenario for aqueous alteration of these rocks and outcrops is that vapors and/or fluids rich in SO2 (volcanic source) and water interacted with rocks that were basaltic in bulk composition. Ferric-, Mg-, and Ca-sulfates, phosphates, and amorphous Si occur in several high albedo soils disturbed by the rover's wheels in the Columbia Hills. The mineralogy of these materials suggests the movement of liquid water within the host material and the subsequent evaporation of solutions rich in Fe, Mg, Ca, S, P, and Si. The presence of ferric sulfates suggests that these phases precipitated from highly oxidized, low-pH solutions. Several hypotheses that invoke acid sulfate weathering environments have been suggested for the aqueous formation of sulfate-bearing phases on the surface of Mars including (1) the oxidative weathering of ultramafic igneous rocks containing sulfides; (2) sulfuric acid weathering of basaltic materials by solutions enriched by volcanic gases (e.g., SO2); and (3) acid fog (i.e., vapors rich in H2SO4) weathering of basaltic or basaltic-derived materials.

  8. Remediation of Acid Mine Drainage with Sulfate Reducing Bacteria

    ERIC Educational Resources Information Center

    Hauri, James F.; Schaider, Laurel A.

    2009-01-01

    Sulfate reducing bacteria have been shown to be effective at treating acid mine drainage through sulfide production and subsequent precipitation of metal sulfides. In this laboratory experiment for undergraduate environmental chemistry courses, students design and implement a set of bioreactors to remediate acid mine drainage and explain observed…

  9. Sulfated phenolic acids from Dasycladales siphonous green algae.

    PubMed

    Kurth, Caroline; Welling, Matthew; Pohnert, Georg

    2015-09-01

    Sulfated aromatic acids play a central role as mediators of chemical interactions and physiological processes in marine algae and seagrass. Among others, Dasycladus vermicularis (Scopoli) Krasser 1898 uses a sulfated hydroxylated coumarin derivative as storage metabolite for a protein cross linker that can be activated upon mechanical disruption of the alga. We introduce a comprehensive monitoring technique for sulfated metabolites based on fragmentation patterns in liquid chromatography/mass spectrometry and applied it to Dasycladales. This allowed the identification of two new aromatic sulfate esters 4-(sulfooxy)phenylacetic acid and 4-(sulfooxy)benzoic acid. The two metabolites were synthesized to prove the mass spectrometry-based structure elucidation in co-injections. We show that both metabolites are transformed to the corresponding desulfated phenols by sulfatases of bacteria. In biofouling experiments with Escherichia coli and Vibrio natriegens the desulfated forms were more active than the sulfated ones. Sulfatation might thus represent a measure of detoxification that enables the algae to store inactive forms of metabolites that are activated by settling organisms and then act as defense.

  10. Microstructural and microanalytical studies of sulfate attack. 3: Sulfate-resisting Portland cement -- Reactions with sodium and magnesium sulfate solutions

    SciTech Connect

    Gollop, R.S.; Taylor, H.F.W.

    1995-10-01

    Cubes of a sulfate-resisting Portland cement (SRPC) paste that had been stored for 6 months in solutions of Na{sub 2}SO{sub 4} or MgSO{sub 4} were examined by scanning electron microscopy using backscattered electron imaging and X-ray microanalysis. The changes observed were broadly similar to those which the authors have found with a normal Portland cement (PC), but cracking and loss of material were less marked, less ettringite was formed, and decalcification of the C-S-H was much reduced. At with the PC gypsum was formed, both in veins and mixed with the C-S-H. The differences are attributed to the low content of Al{sub 2}O{sub 3} in the hydration products of the SRPC, and to the fact that some of the Al{sub 2}O{sub 3} is already present as ettringite. The decreased formation of ettringite and decreased decalcification of the C-S-H in the SRPC together explain the superior resistance to sulfate attack.

  11. Isotopically exchangeable Al in coastal lowland acid sulfate soils.

    PubMed

    Yvanes-Giuliani, Yliane A M; Fink, D; Rose, J; Waite, T David; Collins, Richard N

    2016-01-15

    Periodic discharges of high concentrations of aluminium (Al) causing fish kills and other adverse effects occur worldwide in waterways affected by coastal lowland acid sulfate soils (CLASS). The exchangeability - a metal's ability to readily transfer between the soil solid- and solution-phases - of Al in these soils is therefore of particular importance as it has implications for metal transport, plant availability and toxicity to living organisms. In the present study, the concentrations of isotopically exchangeable Al (E values) were measured in 27 CLASS and compared with common salt extractions (i.e. KCl and CuCl2) used to estimate exchangeable soil pools of Al. E values of Al were high in the soils, ranging from 357 to 3040 mg·kg(-1). Exchangeable concentrations estimated using 1 M KCl were consistently lower than measured E values, although a reasonable correlation was obtained between the two values (E=1.68×AlKCl, r(2)=0.66, n=25). The addition of a 0.2 M CuCl2 extraction step improved the 1:1 agreement between extractable and isotopically exchangeable Al concentrations, but lead to significant mobilisation of non-isotopically exchangeable Al in surficial 'organic-rich' CLASS having E values<1000 mg·kg(-1). It was concluded that currently used (i.e. 1 M KCl) methodology severely underestimates exchangeable Al and total actual acidity values in CLASS and should be corrected by a factor similar to the one determined here.

  12. Remediation of acid mine drainage with sulfate reducing bacteria

    SciTech Connect

    Hauri, J.F.; Schaider, L.A.

    2009-02-15

    Sulfate reducing bacteria have been shown to be effective at treating acid mine drainage through sulfide production and subsequent precipitation of metal sulfides. In this laboratory experiment for undergraduate environmental chemistry courses, students design and implement a set of bioreactors to remediate acid mine drainage and explain observed changes in dissolved metal concentrations and pH. Using synthetic acid mine drainage and combinations of inputs, students monitor their bioreactors for decreases in dissolved copper and iron concentrations.

  13. ELECTRON DETACHMENT DISSOCIATION OF SYNTHETIC HEPARAN SULFATE GLYCOSAMINOGLYCAN TETRASACCHARIDES VARYING IN DEGREE OF SULFATION AND HEXURONIC ACID STEREOCHEMISTRY.

    PubMed

    Leach, Franklin E; Arungundram, Sailaja; Al-Mafraji, Kanar; Venot, Andre; Boons, Geert-Jan; Amster, I Jonathan

    2012-12-15

    Glycosaminoglycan (GAG) carbohydrates provide a challenging analytical target for structural determination due to their polydisperse nature, non-template biosynthesis, and labile sulfate modifications. The resultant structures, although heterogeneous, contain domains which indicate a sulfation pattern or code that correlates to specific function. Mass spectrometry, in particular electron detachment dissociation Fourier transform ion cyclotron resonance (EDD FT-ICR MS), provides a highly sensitive platform for GAG structural analysis by providing cross-ring cleavages for sulfation location and product ions specific to hexuronic acid stereochemistry. To investigate the effect of sulfation pattern and variations in stereochemistry on EDD spectra, a series of synthetic heparan sulfate (HS) tetrasaccharides are examined. Whereas previous studies have focused on lowly sulfated compounds (0.5-1 sulfate groups per disaccharide), the current work extends the application of EDD to more highly sulfated tetrasaccharides (1-2 sulfate groups per disaccharide) and presents the first EDD of a tetrasaccharide containing a sulfated hexuronic acid. For these more highly sulfated HS oligomers, alternative strategies are shown to be effective for extracting full structural details. These strategies inlcude sodium cation replacement of protons, for determining the sites of sulfation, and desulfation of the oligosaccharides for the generation of product ions for assigning uronic acid stereochemistry.

  14. Chondroitin Sulfate in Solution: Effects of Mono- and Divalent Salts

    PubMed Central

    Horkay, Ferenc; Basser, Peter J.; Hecht, Anne-Marie; Geissler, Erik

    2013-01-01

    Chondroitin sulphate (CS) is a linear sulfated polysaccharide found in cartilage and other tissues in the body. Small angle neutron scattering (SANS) and dynamic light scattering (DLS) measurements are made on semi-dilute CS solutions to determine ion induced changes in the local order of the CS chains and in their dynamic properties. In salt-free CS solutions SANS detects the correlation peak due to local ordering between adjacent chains in which the characteristic interchain distance is d ≈ 57 Å. In both monovalent and divalent salts (NaCl and CaCl2) aligned linear regions are distinguishable corresponding to distance scales ranging from the length of the monomer unit (8 Å) to about 1000 Å. With increasing calcium ion concentration, the scattering intensity increases. Even in the presence of 200 mM CaCl2, however, neither phase separation nor cross-linking occurs. DLS in the CS solutions reveals two characteristic relaxation modes, the fast mode corresponding to the thermal concentration fluctuations. The collective diffusion coefficient D decreases with increasing calcium ion concentration and exhibits a power law function of the single variable c/J, where c is the CS concentration and J is the ionic strength of the salt in the solution. This result implies that the effect of the sodium and calcium ions on the dynamic properties of CS solutions is fully accounted for by the ionic strength. PMID:23814316

  15. Ambient aerosols remain highly acidic despite dramatic sulfate reductions

    NASA Astrophysics Data System (ADS)

    Nenes, Athanasios; Weber, Rodney; Guo, Hongyu; Russell, Armistead

    2016-04-01

    The pH of fine particles has many vital environmental impacts. By affecting aerosol concentrations, chemical composition and toxicity, particle pH is linked to regional air quality and climate, and adverse effects on human health. Sulfate is often the main acid component that drives pH of fine particles (i.e., PM2.5) and is neutralized to varying degrees by gas phase ammonia. Sulfate levels have decreased by approximately 70% over the Southeastern United States in the last fifteen years, but measured ammonia levels have been fairly steady implying the aerosol may becoming more neutral. Using a chemically comprehensive data set, combined with a thermodynamic analysis, we show that PM2.5 in the Southeastern U.S. is highly acidic (pH between 0 and 2), and that pH has remained relatively unchanged throughout the past decade and a half of decreasing sulfate. Even with further sulfate reductions, pH buffering by gas-particle partitioning of ammonia is expected to continue until sulfate drops to near background levels, indicating that fine particle pH will remain near current levels into the future. These results are non-intuitive and reshape expectations of how sulfur emission reductions impact air quality in the Southeastern U.S. and possibly other regions across the globe.

  16. Mixed metal phospho-sulfates for acid catalysis

    SciTech Connect

    Thoma, S.G.; Jackson, N.B.; Nenoff, T.M.; Maxwell, R.S.

    1997-12-01

    Mixed metal phospho-sulfates have been prepared and evaluated for use as acid catalysts via 2-methyl-2-pentene isomerization and o-xylene isomerization. Particular members of this class of materials exhibit greater levels of activity than sulfated zirconia as well as lower rates and magnitudes of deactivation. {sup 31}P MAS NMR has been used to examine the role of phosphorus in contributing to the activity and deactivation behavior of these materials, while powder x-ray diffraction, BET surface area, IR, and elemental analysis were used to characterize the bulk catalysts.

  17. The effect of temperature on the speciation of U(VI) in sulfate solutions

    SciTech Connect

    Rao, Linfeng; Tian, Guoxin

    2008-09-15

    Sulfate, one of the inorganic constituents that could be present in the nuclear waste repository, forms complexes with U(VI) and affects its migration in the environment. Results show that the complexation of U(VI) with sulfate is enhanced by the increase in temperature. The effect of temperature on the complexation and speciation of U(VI) in sulfate solutions is discussed.

  18. 21 CFR 520.1044b - Gentamicin sulfate pig pump oral solution.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Gentamicin sulfate pig pump oral solution. 520....1044b Gentamicin sulfate pig pump oral solution. (a) Specifications. Each milliliter of pig pump oral.... (d) Conditions of use—(1) Amount. Administer 1.15 milliliters of pig pump oral solution (5...

  19. 21 CFR 520.1044b - Gentamicin sulfate pig pump oral solution.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Gentamicin sulfate pig pump oral solution. 520....1044b Gentamicin sulfate pig pump oral solution. (a) Specifications. Each milliliter of pig pump oral.... (d) Conditions of use—(1) Amount. Administer 1.15 milliliters of pig pump oral solution (5...

  20. 21 CFR 520.1044b - Gentamicin sulfate pig pump oral solution.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Gentamicin sulfate pig pump oral solution. 520....1044b Gentamicin sulfate pig pump oral solution. (a) Specifications. Each milliliter of pig pump oral.... (d) Conditions of use—(1) Amount. Administer 1.15 milliliters of pig pump oral solution (5...

  1. 21 CFR 520.1044b - Gentamicin sulfate pig pump oral solution.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Gentamicin sulfate pig pump oral solution. 520....1044b Gentamicin sulfate pig pump oral solution. (a) Specifications. Each milliliter of pig pump oral.... (d) Conditions of use—(1) Amount. Administer 1.15 milliliters of pig pump oral solution (5...

  2. 21 CFR 520.1044b - Gentamicin sulfate pig pump oral solution.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Gentamicin sulfate pig pump oral solution. 520....1044b Gentamicin sulfate pig pump oral solution. (a) Specifications. Each milliliter of pig pump oral.... (d) Conditions of use—(1) Amount. Administer 1.15 milliliters of pig pump oral solution (5...

  3. Precipitation of phenyl and phenoxypenicillin from solutions using ammonium sulfate.

    PubMed

    Luengo, J M

    1985-09-01

    An easy, rapid, and available method for separating 6-aminopenicillanic acid (6-APA), benzylpenicillin (penicillin G), and other related molecules from aqueous solutions or complex industrial broths is described. A high concentration of ammonium sulphate induces partially or totally the precipitation of the penicillin present in the solutions, while 6-APA, phenylacetic, and phenoxyacetic acid always remain in the supernatant. The filtration through No. 4 Pyrex glass-fiber filter or Whatman 3MM paper permits the separation of the compounds present in the supernatant from the other ones precipitated. The precipitated product was identified, in all cases, as ammonium penicillin. This method is described here for the first time.

  4. Ice nucleation in internally mixed ammonium sulfate/dicarboxylic acid particles

    NASA Astrophysics Data System (ADS)

    Wise, Matthew E.; Garland, Rebecca M.; Tolbert, Margaret A.

    2004-10-01

    Recent studies have shown that tropospheric sulfate aerosols commonly contain 50% or more by mass organic species. The influence of these organics on the chemical and physical properties of sulfate aerosols is not fully established. Using an aerosol flow tube technique, we have determined ice nucleation temperatures for particles composed of ammonium sulfate and mixtures of ammonium sulfate with a series of dicarboxylic acids. A calibration curve was developed to allow us to convert the freezing temperatures to a saturation ratio required for ice nucleation. At levels detectable by our experimental technique we find that the freezing temperatures and critical ice saturation ratios of each system were identical, for a given water activity of the solution, even though the solutions contained varying fractions of inorganic and organic components. Further experiments showed that the freezing behavior of pure dicarboxylic acid particles was identical to that of the other systems studied if the water activity was identical. Although the apparent freezing temperatures reported here are substantially warmer than those predicted by the water activity based nucleation theory of T. Koop et al., we find that solution water activity defined the freezing conditions for the systems studied here.

  5. 40 CFR 417.120 - Applicability; description of the sulfamic acid sulfation subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... sulfamic acid sulfation subcategory. 417.120 Section 417.120 Protection of Environment ENVIRONMENTAL... CATEGORY Sulfamic Acid Sulfation Subcategory § 417.120 Applicability; description of the sulfamic acid sulfation subcategory. The provisions of this subpart are applicable to discharges resulting from...

  6. 40 CFR 417.130 - Applicability; description of the chlorosulfonic acid sulfation subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... chlorosulfonic acid sulfation subcategory. 417.130 Section 417.130 Protection of Environment ENVIRONMENTAL... CATEGORY Chlorosulfonic Acid Sulfation Subcategory § 417.130 Applicability; description of the chlorosulfonic acid sulfation subcategory. The provisions of this subpart are applicable to discharges...

  7. 40 CFR 417.120 - Applicability; description of the sulfamic acid sulfation subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... sulfamic acid sulfation subcategory. 417.120 Section 417.120 Protection of Environment ENVIRONMENTAL... CATEGORY Sulfamic Acid Sulfation Subcategory § 417.120 Applicability; description of the sulfamic acid sulfation subcategory. The provisions of this subpart are applicable to discharges resulting from...

  8. 40 CFR 417.130 - Applicability; description of the chlorosulfonic acid sulfation subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... chlorosulfonic acid sulfation subcategory. 417.130 Section 417.130 Protection of Environment ENVIRONMENTAL... CATEGORY Chlorosulfonic Acid Sulfation Subcategory § 417.130 Applicability; description of the chlorosulfonic acid sulfation subcategory. The provisions of this subpart are applicable to discharges...

  9. 75 FR 78243 - Propionic Acid and Salts, Urea Sulfate, Methidathion, and Methyl Parathion; Registration Review...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-15

    ... AGENCY Propionic Acid and Salts, Urea Sulfate, Methidathion, and Methyl Parathion; Registration Review... pesticides propionic acid and salts, case no. 4078, urea sulfate, case no. 7213, methidathion, case no. 0034... pesticides in the table below--propionic acid and salts, case 4078, urea sulfate, case no. 7213,...

  10. Application of acidic calcium sulfate and e-polylysine to pre-rigor beef rounds for reduction of pathogens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Foodborne illness continues to be a serious public health problem and is a major concern for the United States food industry. This study evaluated the effectiveness of warm solutions of acidic calcium sulfate (ACS), lactic acid (LA), episolon-polylysine (EPL), ACS plus EPL, and sterile distilled wa...

  11. Low temperature aqueous ferric sulfate solutions on the surface of Mars

    NASA Astrophysics Data System (ADS)

    Chevrier, Vincent F.; Altheide, Travis S.

    2008-11-01

    We have studied the low-temperature properties of ferric sulfate Fe2(SO4)3 solutions as a model for potential liquid brines on the surface of Mars. Geochemical modeling demonstrates that concentrated ferric sulfate brines form through sulphur-rich acidic evaporation processes in cold oxidizing environments. Experiments and thermodynamic calculations show that the Fe2(SO4)3 eutectic temperature is 205 +/- 1 K for 48 +/- 2 wt% concentration. As a result of low water activity, these solutions exhibit evaporation rates ranging from 0.42 mm h-1 (29.1 wt%) to 0.03 mm h-1 (58.2 wt%), thus down to 20 times lower than pure water. The combination of extremely low eutectic temperature and evaporation rates allow subsurface liquids to be stable at high latitudes, where the majority of gullies and viscous flow features are located. Therefore, we conclude that episodic releases of highly concentrated ferric sulfate brines are a potential agent for the formation of recent and present-day gullies on Mars.

  12. Lung-clearance mechanisms following inhalation of acid sulfates

    SciTech Connect

    Wolff, R.K.; Muggenburg, B.A.; Silbaugh, S.A.; Carpenter, R.L.; Rowatt, J.D.; Hill, J.O.

    1982-08-01

    These studies have indicated that acute exposures (1-6 hrs) to sulfuric acid at levels of 0.5 to 1.0 mg/m/sup 3/ can produce impairments in mucous clearance. The impairments can last for up to a week following a 1 hr exposure. These effects and studies by others suggest that high sulfate levels in polluted conditions may be one factor in observed increases of hospital visits for respiratory problems. Long term exposures to elevated levels of sulfates resulting in decreases of clearance could also be an initiating factor in producing chronic obstructive pulmonary disease (COPD). These studies have also shown that it is the larger size fraction (0.6 to 1.0 ..mu..m) of sulfuric acid mist in the urban aerosol which is predominantly responsible for at least the acute effects.

  13. Statics of molybdenum sorption from manganese(II) sulfate solutions on porous and macronetwork anion-exchange resin AN-108

    SciTech Connect

    Kholmogorov, A.G.; Kononova, O.N.; Pashkov, G.L.

    1994-11-20

    The statics have been considered of the ion-exchange equilibrium in the system R{sub 2}SO{sub 4}-MnSO{sub 4}-H{sub 2}SO{sub 4}-Mo(VI)-H{sub 2}O in recovery of molybdenum(VI) ions from sulfate solutions of manganese(II) in relation to the sulfuric acid concentration, physical and chemical structure of the ion-exchange resin, and solution temperatures.

  14. Glyoxal in aqueous ammonium sulfate solutions: products, kinetics and hydration effects.

    PubMed

    Yu, Ge; Bayer, Amanda R; Galloway, Melissa M; Korshavn, Kyle J; Fry, Charles G; Keutsch, Frank N

    2011-08-01

    Reactions and interactions between glyoxal and salts in aqueous solution were studied. Glyoxal was found to react with ammonium to form imidazole, imidazole-2-carboxaldehyde, formic acid, N-glyoxal substituted imidazole, and minor products at very low concentrations. Overall reaction orders and rates for each major product were measured. Sulfate ions have a strong and specific interaction with glyoxal in aqueous solution, which shifts the hydration equilibria of glyoxal from the unhydrated carbonyl form to the hydrated form. This ion-specific effect contributes to the observed enhancement of the effective Henry's law coefficient for glyoxal in sulfate-containing solutions. The results of UV-vis absorption and NMR spectroscopy studies of solutions of glyoxal with ammonium, methylamine, and dimethylamine salts reveal that light absorbing compounds require the formation of nitrogen containing molecules. These findings have implications on the role of glyoxal in the atmosphere, both in models of the contribution of glyoxal to form secondary organic aerosol (SOA), the role of nitrogen containing species for aerosol optical properties and in predictions of the behavior of other carbonyls or dicarbonyls in the atmosphere.

  15. Sulfation mediates activity of zosteric acid against biofilm formation.

    PubMed

    Kurth, Caroline; Cavas, Levent; Pohnert, Georg

    2015-01-01

    Zosteric acid (ZA), a metabolite from the marine sea grass Zostera marina, has attracted much attention due to its attributed antifouling (AF) activity. However, recent results on dynamic transformations of aromatic sulfates in marine phototrophic organisms suggest potential enzymatic desulfation of metabolites like ZA. The activity of ZA was thus re-investigated using biofilm assays and simultaneous analytical monitoring by liquid chromatography/mass spectrometry (LC/MS). Comparison of ZA and its non-sulfated form para-coumaric acid (CA) revealed that the active substance was in all cases the non-sulfated CA while ZA was virtually inactive. CA exhibited a strong biofilm inhibiting activity against Escherichia coli and Vibrio natriegens. The LC/MS data revealed that the apparent biofilm inhibiting effects of ZA on V. natriegens can be entirely attributed to CA released from ZA by sulfatase activity. In the light of various potential applications, the (a)biotic transformation of ZA to CA has thus to be considered in future AF formulations.

  16. Reactive solute transport in acidic streams

    USGS Publications Warehouse

    Broshears, R.E.

    1996-01-01

    Spatial and temporal profiles of Ph and concentrations of toxic metals in streams affected by acid mine drainage are the result of the interplay of physical and biogeochemical processes. This paper describes a reactive solute transport model that provides a physically and thermodynamically quantitative interpretation of these profiles. The model combines a transport module that includes advection-dispersion and transient storage with a geochemical speciation module based on MINTEQA2. Input to the model includes stream hydrologic properties derived from tracer-dilution experiments, headwater and lateral inflow concentrations analyzed in field samples, and a thermodynamic database. Simulations reproduced the general features of steady-state patterns of observed pH and concentrations of aluminum and sulfate in St. Kevin Gulch, an acid mine drainage stream near Leadville, Colorado. These patterns were altered temporarily by injection of sodium carbonate into the stream. A transient simulation reproduced the observed effects of the base injection.

  17. Influence and hydrolysis kinetics in titanyl sulfate solution from the sodium hydroxide molten salt method

    NASA Astrophysics Data System (ADS)

    Wang, Weijing; Chen, Desheng; Chu, Jinglong; Li, Jie; Xue, Tianyan; Wang, Lina; Wang, Dong; Qi, Tao

    2013-10-01

    Hydrated titanium dioxide (HTD) was precipitated by thermal hydrolysis in purified titanyl sulfate solution (TSS) obtained through the sodium hydroxide molten salt clean method. Various factors including the stirring speed and initial concentrations of TiOSO4, sulfuric acid, and sodium ion were studied. The main influence factors in the hydrolysis process were the initial concentrations of TiOSO4 and sulfuric acid. Contrary to the ferrous ion, the sodium ion improved the ionic activity of Ti4+, but did not decrease the crystal size. The Boltzman growth model (x=A2+(A1-A2)/{1+exp[(t-t0)/dt)]}, which focuses on two main parameters (CTiOSO4 and CH2SO4), fits the hydrolysis process well with R2>0.97. An increase in sulfuric acid concentration negatively affected the hydrolysis rates and the value of A2, while t0 increased. An increase in titanyl sulfate concentration directly reduced the hydrolysis rates and particle size of HTD, contrary to the trend for the value of t0. A simulation software called 1stopt was used to observe the relationship between Z (A1, A2, t0, dt) and a, b (CTiO2 and CH2SO4).

  18. [Newly leaching method of copper from waste print circuit board using hydrochloric acid/n-butylamine/copper sulfate].

    PubMed

    Wang, Hong-Yan; Cui, Zhao-Jie; Yao, Ya-Wei

    2010-12-01

    A newly leaching method of copper from waste print circuit board was established by using hydrochloric acid-n-butylamine-copper sulfate mixed solution. The conditions of leaching were optimized by changing the hydrochloric acid, n-butylamine, copper sulfate,temperature and other conditions using copper as target mimics. The results indicated that copper could be leached completely after 8 h at 50 degrees C, hydrochloric acid concentration of 1.75 mol/L, n-butylamine concentration of 0.25 mol/L, and copper sulfate mass of 0.96 g. Under the conditions, copper leaching rates in waste print circuit board samples was up to 95.31% after 9 h. It has many advantages such as better effects, low cost, mild reaction conditions, leaching solution recycling.

  19. Smectite Formation in Acid Sulfate Environments on Mars

    NASA Technical Reports Server (NTRS)

    Peretyazhko, T. S.; Niles, P. B.; Sutter, B.; Clark, J. V.; Morris, R. V.; Ming, D. W.

    2017-01-01

    Phyllosilicates of the smectite group detected in Noachian and early Hesperian terrains on Mars were hypothesized to form under aqueous conditions that were globally neutral to alkaline. These pH conditions and the presence of a CO2-rich atmosphere should have been favorable for the formation of large carbonate deposits. However, large-scale carbonate deposits have not been detected on Mars. We hypothesized that smectite deposits are consistent with perhaps widespread acidic aqueous conditions that prevented carbonate precipitation. The objective of our work was to investigate smectite formation under acid sulfate conditions in order to provide insight into the possible geochemical conditions required for smectite formation on Mars. Hydrothermal batch incubation experiments were performed with Mars-analogue, glass-rich, basalt simulant in the presence of sulfuric acid of variable concentration.

  20. Microarray and Functional Gene Analyses of Sulfate-Reducing Prokaryotes in Low-Sulfate, Acidic Fens Reveal Cooccurrence of Recognized Genera and Novel Lineages

    PubMed Central

    Loy, Alexander; Küsel, Kirsten; Lehner, Angelika; Drake, Harold L.; Wagner, Michael

    2004-01-01

    Low-sulfate, acidic (approximately pH 4) fens in the Lehstenbach catchment in the Fichtelgebirge mountains in Germany are unusual habitats for sulfate-reducing prokaryotes (SRPs) that have been postulated to facilitate the retention of sulfur and protons in these ecosystems. Despite the low in situ availability of sulfate (concentration in the soil solution, 20 to 200 μM) and the acidic conditions (soil and soil solution pHs, approximately 4 and 5, respectively), the upper peat layers of the soils from two fens (Schlöppnerbrunnen I and II) of this catchment displayed significant sulfate-reducing capacities. 16S rRNA gene-based oligonucleotide microarray analyses revealed stable diversity patterns for recognized SRPs in the upper 30 cm of both fens. Members of the family “Syntrophobacteraceae” were detected in both fens, while signals specific for the genus Desulfomonile were observed only in soils from Schlöppnerbrunnen I. These results were confirmed and extended by comparative analyses of environmentally retrieved 16S rRNA and dissimilatory (bi)sulfite reductase (dsrAB) gene sequences; dsrAB sequences from Desulfobacca-like SRPs, which were not identified by microarray analysis, were obtained from both fens. Hypotheses concerning the ecophysiological role of these three SRP groups in the fens were formulated based on the known physiological properties of their cultured relatives. In addition to these recognized SRP lineages, six novel dsrAB types that were phylogenetically unrelated to all known SRPs were detected in the fens. These dsrAB sequences had no features indicative of pseudogenes and likely represent novel, deeply branching, sulfate- or sulfite-reducing prokaryotes that are specialized colonists of low-sulfate habitats. PMID:15574893

  1. Similarities Across Mars: Acidic Fluids at Both Meridiani Planum and Gale Crater in the Formation of Magnesium-Nickel Sulfates

    NASA Technical Reports Server (NTRS)

    Yen, Albert S.; Ming, Douglas W.; Gellert, Ralf; Mittlefehldt, David W.; Vaniman, David T.; Thompson, Lucy M.; Morris, Richard V.; Clark, Benton C.; Arvidson, Raymond

    2016-01-01

    In-situ identification of sulfates at the martian surface by the Mars Exploration Rovers and the Mars Science Laboratory have included calcium sulfates with various states of hydration (gypsum, bassanite, anhydrite), iron sulfates of likely fumarolic origin, massive deposits of iron hydroxysulfates indicative of an acidic history, and minor occurrences of magnesium sulfates. Recent measurements by the Opportunity and Curiosity Alpha Particle X-ray Spectrometers (APXS) have indicated the presence of Ni-substituted Mg-sulfates at the Meridiani Planum and Gale Crater landing sites. The Opportunity rover has traversed nearly 43 km and is currently exploring the impact breccias of the rim of Endeavour crater, near a location where signatures of aqueous alteration have been established from orbit. APXS analyses of subsurface materials excavated by a rover wheel show clear evidence for a Mg(Ni)-sulfate with Mg:Ni (is) approximately 100:1 (molar). On the other side of the planet, Curiosity is continuing its climb up Mount Sharp after driving (is) approximately 13 km since landing. Over the last 4 km of the traverse, there have been multiple chemical analyses of erosionally-resistant nodules and dendritic features in a finely laminated mudstone unit which also indicate Mg(Ni)-sulfate (Mg:Ni (is) approximately 30:1, molar). The geologic settings for the Endeavour rim and the Mount Sharp mudstones are clearly different, but similar formation conditions for these sulfates may be possible. Ni(2+) readily substitutes for Mg(2+) in a variety of geochemical processes due to their comparable ionic radii. The availability of soluble Ni at the time of Mg-sulfate precipitation suggests acidic solutions. The fluids responsible for alteration in the Endeavour rim and for the formation of nodules in Gale mudstones may have had similar chemical characteristics at the time the Mg-sulfates were formed.

  2. Chemoenzymatic synthesis and structural characterization of 2-O-sulfated glucuronic acid-containing heparan sulfate hexasaccharides

    PubMed Central

    Hsieh, Po-Hung; Xu, Yongmei; Keire, David A; Liu, Jian

    2014-01-01

    Heparan sulfate and heparin are highly sulfated polysaccharides that consist of a repeating disaccharide unit of glucosamine and glucuronic or iduronic acid. The 2-O-sulfated iduronic acid (IdoA2S) residue is commonly found in heparan sulfate and heparin; however, 2-O-sulfated glucuronic acid (GlcA2S) is a less abundant monosaccharide (∼<5% of total saccharides). Here, we report the synthesis of three GlcA2S-containing hexasaccharides using a chemoenzymatic approach. For comparison purposes, additional IdoA2S-containing hexasaccharides were synthesized. Nuclear magnetic resonance analyses were performed to obtain full chemical shift assignments for the GlcA2S- and IdoA2S-hexasaccharides. These data show that GlcA2S is a more structurally rigid saccharide residue than IdoA2S. The antithrombin (AT) binding affinities of a GlcA2S- and an IdoA2S-hexasaccharide were determined by affinity co-electrophoresis. In contrast to IdoA2S-hexasaccharides, the GlcA2S-hexasaccharide does not bind to AT, confirming that the presence of IdoA2S is critically important for the anticoagulant activity. The availability of pure synthetic GlcA2S-containing oligosaccharides will allow the investigation of the structure and activity relationships of individual sites in heparin or heparan sulfate. PMID:24770491

  3. Methanol Uptake by Low Temperature Aqueous Sulfuric Acid Solutions

    NASA Technical Reports Server (NTRS)

    Iraci, L. T.; Essin, A. M.; Golden, D. M.; Hipskind, R. Stephen (Technical Monitor)

    2001-01-01

    The global methanol budget is currently unbalanced, with source terms significantly larger than the sinks terms. To evaluate possible losses of gaseous methanol to sulfate aerosols, the solubility and reactivity of methanol in aqueous sulfuric acid solutions representative of upper tropospheric and lower stratospheric aerosols is under investigation. Methanol will partition into sulfate aerosols according to its Henry's law solubility. Using standard uptake techniques in a Knudsen cell reactor, we have measured the effective Henry's law coefficient, H*, for cold (196 - 220 K) solutions ranging between 45 and 70 wt % H2SO4. We have found that methanol solubility ranges from approx. 10(exp 5) - 10(exp 7) M/atm for UT/LS conditions. Solubility increases with decreasing temperature and with increasing sulfuric acid content. Although methanol is slightly more soluble than are acetone and formaldehyde, current data indicate that uptake by clean aqueous sulfuric acid particles will not be a significant sink for methanol in the UT/LS. These solubility measurements include uptake due to physical solvation and any rapid equilibria which are established in solution. Reaction between primary alcohols and sulfuric acid does occur, leading to the production of alkyl sulfates. Literature values for the rate of this reaction suggest that formation of CH3OSO3H is not significant over our experimental time scale for solutions below 80 wt % H2SO4. To confirm this directly, results obtained using a complementary equilibrium measurement technique will also be presented.

  4. Sulfate reduction at low pH to remediate acid mine drainage.

    PubMed

    Sánchez-Andrea, Irene; Sanz, Jose Luis; Bijmans, Martijn F M; Stams, Alfons J M

    2014-03-30

    Industrial activities and the natural oxidation of metallic sulfide-ores produce sulfate-rich waters with low pH and high heavy metals content, generally termed acid mine drainage (AMD). This is of great environmental concern as some heavy metals are highly toxic. Within a number of possibilities, biological treatment applying sulfate-reducing bacteria (SRB) is an attractive option to treat AMD and to recover metals. The process produces alkalinity, neutralizing the AMD simultaneously. The sulfide that is produced reacts with the metal in solution and precipitates them as metal sulfides. Here, important factors for biotechnological application of SRB such as the inocula, the pH of the process, the substrates and the reactor design are discussed. Microbial communities of sulfidogenic reactors treating AMD which comprise fermentative-, acetogenic- and SRB as well as methanogenic archaea are reviewed.

  5. Effects of oxalic acid on availability of zinc from spinach leaves and zinc sulfate to rats.

    PubMed

    Welch, R M; House, W A; Van Campen, D

    1977-06-01

    Some effects of dietary oxalic acid on availability of zinc from organic and inorganic sources were assessed. Male rats fed zinc-deficient diets with and without added sodium oxalate were orally dosed once with either 65Zn-labeled spinach leaves or 65Zn-labeled zinc sulfate. Spinach plants (Spinacia oleracea, var. "Winter Bloomsdale") were grown in 65Zn-labeled nutrient solutions that contained 0.033, 0.131 or 0.262 ppm zinc. Increasing zinc supply to the plants increased zinc concentration in the leaves. Oxalic acid content in all leaves was about 7% dry weight. Dietary oxalate enhanced the availability of 65Zn from zinc sulfate, but had no effect on absorption and retention of 65Zn from spinach leaves. Regardless of dietary oxalate levels, absorption and retention of 65Zn was greater from spinach leaves than from zinc sulfate. We concluded that endogenous zinc in spinach leaves was readily available to zinc-deficient rats, and that dietary oxalate was not deleterious to zinc availability.

  6. Analysis of Drosophila glucuronyl C5-epimerase: implications for developmental roles of heparan sulfate sulfation compensation and 2-O-sulfated glucuronic acid.

    PubMed

    Dejima, Katsufumi; Takemura, Masahiko; Nakato, Eriko; Peterson, Jesse; Hayashi, Yoshiki; Kinoshita-Toyoda, Akiko; Toyoda, Hidenao; Nakato, Hiroshi

    2013-11-29

    During the biosynthesis of heparan sulfate (HS), glucuronyl C5-epimerase (Hsepi) catalyzes C5-epimerization of glucuronic acid (GlcA), converting it to iduronic acid (IdoA). Because HS 2-O-sulfotransferase (Hs2st) shows a strong substrate preference for IdoA over GlcA, C5-epimerization is required for normal HS sulfation. However, the physiological significance of C5-epimerization remains elusive. To understand the role of Hsepi in development, we isolated Drosophila Hsepi mutants. Homozygous mutants are viable and fertile with only minor morphological defects, including the formation of an ectopic crossvein in the wing, but they have a short lifespan. We propose that two mechanisms contribute to the mild phenotypes of Hsepi mutants: HS sulfation compensation and possible developmental roles of 2-O-sulfated GlcA (GlcA2S). HS disaccharide analysis showed that loss of Hsepi resulted in a significant impairment of 2-O-sulfation and induced compensatory increases in N- and 6-O-sulfation. Simultaneous block of Hsepi and HS 6-O-sulfotransferase (Hs6st) activity disrupted tracheoblast formation, a well established FGF-dependent process. This result suggests that the increase in 6-O-sulfation in Hsepi mutants is critical for the rescue of FGF signaling. We also found that the ectopic crossvein phenotype can be induced by expression of a mutant form of Hs2st with a strong substrate preference for GlcA-containing units, suggesting that this phenotype is associated with abnormal GlcA 2-O-sulfation. Finally, we show that Hsepi formed a complex with Hs2st and Hs6st in S2 cells, raising the possibility that this complex formation contributes to the close functional relationships between these enzymes.

  7. The stable isotope geochemistry of acid sulfate alteration

    USGS Publications Warehouse

    Rye, R.O.; Bethke, P.M.; Wasserman, M.D.

    1992-01-01

    Acid sulfate wall-rock alteration, characterized by the assemblage alunite + kaolinite + quartz ?? pyrite, results from base leaching by fluids concentrated in H2SO4. Requisite amounts of H2SO4 can be generated by different mechanisms in three principal geologic environments: 1) by atmospheric oxidation of sulfides in the supergene environment, 2) by atmospheric oxidation at the water table in the steam-heated environment of H2S released by deeper, boiling fluids, and 3) by the disproportionation of magmatic SO2 to H2S and H2SO4 during condensation of a magmatic vapor plume at intermediate depths in magmatic hydrothermal environments in silicic and andesitic volcanic terranes. In addition, coarse vein alunite may form in a magmatic steam environment. -from Authors

  8. Solvent extraction separation of nickel and cobalt from a sulfate solution containing iron(II) and magnesium using versatic 10

    NASA Astrophysics Data System (ADS)

    Ichlas, Zela Tanlega; Purwadaria, Sunara

    2017-01-01

    The separation of nickel and cobalt from a synthetic sulfate solution that contains iron(II) and magnesium via solvent extraction techniques using a neodecanoic acid, Versatic 10, as extractant was explored. The extraction behavior of the metals was investigated by varying the operating pH while the stripping behavior was investigated by varying the acidity of the stripping agent which was sulfuric acid. The experimental results demonstrate that nickel, cobalt and iron(II) can be separated easily from magnesium via selective extraction using 20% Versatic 10 as extractant and 5% tri-n-butyl phosphate (TBP) as phase modifier at pH 7.0, while the nickel and cobalt in the loaded organic phase can be separated from iron(II) by selective stripping of the two metals using 0.1 mol/L sulfuric acid solution leaving iron(II) in the organic phase. Attempts to optimize the extraction and stripping processes were reported.

  9. Effect of A Long Chain Carboxylate Acid on Sodium Dodecyl Sulfate Micelle Structure: A SANS Study

    NASA Astrophysics Data System (ADS)

    Patriati, Arum; Giri Rachman Putra, Edy; Seok Seong, Baek

    2010-01-01

    The effect of a different hydrocarbon chain length of carboxylate acid, i.e. dodecanoic acid, CH3(CH)10COOH or lauric acid and hexadecanoic acid, CH3(CH2)14COOH or palmitic acid as a co-surfactant in the 0.3 M sodium dedecyl sulfate, SDS micellar solution has been studied using small angle neutron scattering (SANS). The present of lauric acid has induced the SDS structural micelles. The ellipsoid micelles structures changed significantly in length (major axis) from 22.6 Å to 37.1 Å at a fixed minor axis of 16.7 Å in the present of 0.005 M to 0.1 M lauric acid. Nevertheless, this effect did not occur in the present of palmitic acid with the same concentration range. The present of palmitic acid molecules performed insignificant effect on the SDS micelles growth where the major axis of the micelle was elongated from 22.9 Å to 25.3 Å only. It showed that the appropriate hydrocarbon chain length between surfactant and co-surfactant molecules emerged as one of the determining factors in forming a mixed micelles structure.

  10. Acid sulfate soils are an environmental hazard in Finland

    NASA Astrophysics Data System (ADS)

    Pihlaja, Jouni

    2016-04-01

    Acid sulfate soils (ASS) create significant threats to the environment on coastal regions of the Baltic Sea in Finland. The sediments were deposited during the ancient Litorina Sea phase of the Baltic Sea about 7500-4500 years ago. Finland has larger spatial extent of the ASS than any other European country. Mostly based on anthropogenic reasons (cultivation, trenching etc.) ASS deposits are currently being exposed to oxygen which leads to chemical reaction creating sulfuric acid. The acidic waters then dissolve metals form the soil. Acidic surface run off including the metals are then leached into the water bodies weakening the water quality and killing fish or vegetation. In constructed areas acidic waters may corrode building materials. Geological Survey of Finland (GTK) is mapping ASS deposits in Finland. The goal is to map a total of 5 million hectares of the potentially ASS affected region. It has been estimated that the problematic Litorina Sea deposits, which are situated 0-100 m above the recent Baltic Sea shoreline, cover 500 000 hectares area. There are several phases in mapping. The work begins at the office with gathering the existing data, interpreting airborne geophysical data and compiling a field working plan. In the field, quality of the soil is studied and in uncertain cases samples are taken to laboratory analyses. Also electrical conductivity and pH of soil and water are measured in the field. Laboratory methods include multielemental determinations with ICP-OES, analyses of grain size and humus content (LOI), and incubation. So far, approximately 60 % of the potential ASS affected regions in Finland are mapped. Over 15 000 sites have been studied in the field and 4000 laboratory analyses are done. The spatial database presented in the scale of 1: 250 000 can be viewed at the GTK's web pages (http://gtkdata.gtk.fi/hasu/index.html).

  11. Uptake of Ambient Organic Gases to Acidic Sulfate Aerosols

    NASA Astrophysics Data System (ADS)

    Liggio, J.; Li, S.

    2009-05-01

    The formation of secondary organic aerosols (SOA) in the atmosphere has been an area of significant interest due to its climatic relevance, its effects on air quality and human health. Due largely to the underestimation of SOA by regional and global models, there has been an increasing number of studies focusing on alternate pathways leading to SOA. In this regard, recent work has shown that heterogeneous and liquid phase reactions, often leading to oligomeric material, may be a route to SOA via products of biogenic and anthropogenic origin. Although oligomer formation in chamber studies has been frequently observed, the applicability of these experiments to ambient conditions, and thus the overall importance of oligomerization reactions remain unclear. In the present study, ambient air is drawn into a Teflon smog chamber and exposed to acidic sulfate aerosols which have been formed in situ via the reaction of SO3 with water vapor. The aerosol composition is measured with a High Resolution Aerodyne Aerosol Mass Spectrometer (HR-ToF-AMS), and particle size distributions are monitored with a scanning mobility particle sizer (SMPS). The use of ambient air and relatively low inorganic particle loading potentially provides clearer insight into the importance of heterogeneous reactions. Results of experiments, with a range of sulfate loadings show that there are several competing processes occurring on different timescales. A significant uptake of ambient organic gases to the particles is observed immediately followed by a slow shift towards higher m/z over a period of several hours indicating that higher molecular weight products (possibly oligomers) are being formed through a reactive process. The results suggest that heterogeneous reactions can occur with ambient organic gases, even in the presence of ammonia, which may have significant implications to the ambient atmosphere where particles may be neutralized after their formation.

  12. Processes and fluxes during the initial stage of acid sulfate soil formation

    NASA Astrophysics Data System (ADS)

    Gröger, J.; Hamer, K.; Schulz, H. D.

    2009-04-01

    Acid sulfate soils occur over a wide range of climatic zones, mainly in coastal landscapes. In these soils, the release of sulfuric acid by the oxidation of pyrite generates a very acidic environment (e.g., DENT and PONS, 1995, PONS, 1973). Two major types of acid sulfate soils can be distinguished: In actual acid sulfate soils, the initially contained pyrite was at least partly oxidized. This resulted in a severe acidification of the soil. Potential acid sulfate soils are generally unoxidized and contain large amounts of pyrite. Upon oxidation, these soils will turn into actual acid sulfate soils. By excavation or lowering of the groundwater table, potential acid sulfate soils can be exposed to atmospheric oxygen. During oxidation the pH drops sharply to values below pH 4. This acidification promotes the release of various metals, e.g., alumina, iron and heavy metals. Additionally, large quantities of sulfate are released. In order to assess the effects of disturbances of potential acid sulfate soils, for example by excavations during construction works, several large scale column experiments were conducted with various types of potential acid sulfate soils from Northern Germany. In these experiments, the oxidation and initial profile development of pyritic fen peats and thionic fluvisols were studied over a period of 14 months. The study focused on leaching and the translocation of various metals in the soil profile. To study mobilization processes, element fluxes and the progress of acidification, soil water and leachate were analyzed for total element concentrations. Furthermore, several redox-sensitive parameters, e.g., Fe2+ and sulfide, were measured and changes to the initial solid phase composition were analyzed. Chemical equilibria calculations of the soil water were used to gain insights into precipitation processes of secondary products of pyrite oxidation and leaching products. The results of this study will support the assessment of risks deriving from

  13. A simplified method for estimation of jarosite and acid-forming sulfates in acid mine wastes.

    PubMed

    Li, Jun; Smart, Roger St C; Schumann, Russell C; Gerson, Andrea R; Levay, George

    2007-02-01

    In acid base accounting (ABA) estimates of acid mine wastes, the acid potential (AP) estimate can be improved by using the net carbonate value (NCV) reactive sulfide S method rather than total S assay methods but this does not give recovery of potentially acid producing ferrous and ferric sulfates present in many wastes. For more accurate estimation of AP, an effective, site-specific method to quantify acid sulfate salts, such as jarosite and melanterite, in waste rocks has been developed and tested on synthetic and real wastes. The SPOCAS (acid sulfate soils) methods have been modified to an effective, rapid method to speciate sulfate forms in different synthetic waste samples. A three-step sequential extraction procedure has been established. These steps are: (1) argon-purged water extraction (3 min) to extract soluble Fe(II) salts (particularly melanterite), epsomite and gypsum (<10 wt.%), (2) roasting at 550 degrees C (1 h) to remove sulfur from pyrite and other reactive sulfides, (3) HCl extraction (4 M, 30 min) for determination of jarosites. Products (solid and aqueous) have been characterized at each step including the jarosite decomposition process in Step 2 where temperature control is critical to avoid S loss. The sequential extraction procedure was used to quantitatively determine melanterite, epsomite, gypsum, pyrite and jarosite concentrations in a synthetic waste sample containing these mineral phases at 5 wt.% in quartz, and also tested using a tailings waste sample to quantitatively determine epsomite, gypsum and jarosite contents. The method is applicable to most waste samples including those with non-pyrite sulfides but for samples containing significant amounts of sulfur (>1 wt.% S) as copper sulfides, the second step of roasting needs to be excluded from the procedure with an increased time of 4 M HCl extraction to 16 h for jarosite determination.

  14. Effect of sodium chloride on solute-solvent interactions in aqueous polyethylene glycol-sodium sulfate two-phase systems.

    PubMed

    da Silva, Nuno R; Ferreira, Luisa A; Madeira, Pedro P; Teixeira, José A; Uversky, Vladimir N; Zaslavsky, Boris Y

    2015-12-18

    Partition behavior of eight small organic compounds and six proteins was examined in poly(ethylene glycol)-8000-sodium sulfate aqueous two-phase systems containing 0.215M NaCl and 0.5M osmolyte (sorbitol, sucrose, TMAO) and poly(ethylene glycol)-10000-sodium sulfate-0.215M NaCl system, all in 0.01M sodium phosphate buffer, pH 6.8. The differences between the solvent properties of the coexisting phases (solvent dipolarity/polarizability, hydrogen bond donor acidity, and hydrogen bond acceptor basicity) were characterized with solvatochromic dyes using the solvatochromic comparison method. Differences between the electrostatic properties of the phases were determined by analysis of partitioning of sodium salts of dinitrophenylated (DNP-) amino acids with aliphatic alkyl side-chain. The partition coefficients of all compounds examined (including proteins) were described in terms of solute-solvent interactions. The results obtained in the study show that solute-solvent interactions of nonionic organic compounds and proteins in polyethylene glycol-sodium sulfate aqueous two-phase system change in the presence of NaCl additive.

  15. Acid-Sulfate Alteration at Gusev Crater and Across Mars: High-SiO2 Residues and Ferric Sulfate Precipitates

    NASA Technical Reports Server (NTRS)

    Morris, R. V.; Catalano, J. G.; Klingelhoefer, G.; Schroeder, C.; Gellert, R.; Clark, B. C.; Ming, D. W.; Yen, A. S.; Arvidson, R. E.; Cohen, B. A.; Fleischer, I.; McCoy, T. J.; Mittlefehldt, D. W.; Squyres, S. W.

    2017-01-01

    The Mars Exploration Rover Spirit ended its mission in Gusev crater on sol 2210 after it had become stuck in a deposit of fined-grained and sulfate rich soil with dust covered solar panels unfavorably pointed toward the sun. Final analysis of remaining data from Spirit's Moessbauer spectrometer (Fe redox and mineralogy) for sols 1529 through 2071 is now complete. We focus here on chemical (APXS) and MB data for targets having high-SiO2 or high-SO3 and process link the targets through mixing and geochemical modelling to an acid-sulfate system centered at Home Plate, which is considered to be a hydrovolcanic complex.

  16. Surface characterization of acidic ceria-zirconia prepared by direct sulfation

    NASA Astrophysics Data System (ADS)

    Azambre, B.; Zenboury, L.; Weber, J. V.; Burg, P.

    2010-05-01

    Acidic ceria-zirconia (SCZ) solid acid catalysts with a nominal surface density of ca 2 SO 42-/nm 2 were prepared by a simple route consisting in soaking high specific surface area Ce xZr 1- xO 2 (with x = 0.21 and 0.69) mixed oxides solutions in 0.5 M sulphuric acid. Characterizations by TPD-MS, TP-DRIFTS and FT-Raman revealed that most of surface structures generated by sulfation are stable at least up to 700 °C under inert atmosphere and consist mainly as isolated sulfates located on defects or crystal planes and to a lesser extent as polysulfates. Investigations by pyridine adsorption/desorption have stated that: SCZ possess both strong Brønsted (B) and Lewis (L) acid sites, some of them being presumably superacidic; the B/L site ratio was found to be more dependent on the temperature and hydration degree than on the composition of the ceria-zirconia. By contrast, the reactivity of the parent Ce xZr 1- xO 2 materials towards pyridine is mostly driven by redox properties resulting in the formation of Py-oxide with the participation of Lewis acid sites of moderate strength ( cus Ce x+ and Zr x+ cations). Basicity studies by CO 2 adsorption/desorption reveal that SCZ surfaces are solely acidic whereas the number and strength of Lewis basic sites increases with the Ce content for the parent Ce xZr 1- xO 2 materials.

  17. Iron Absorption from Two Milk Formulas Fortified with Iron Sulfate Stabilized with Maltodextrin and Citric Acid

    PubMed Central

    Pizarro, Fernando; Olivares, Manuel; Maciero, Eugenia; Krasnoff, Gustavo; Cócaro, Nicolas; Gaitan, Diego

    2015-01-01

    Background: Fortification of milk formulas with iron is a strategy widely used, but the absorption of non-heme iron is low. The purpose of this study was to measure the bioavailability of two iron fortified milk formulas designed to cover toddlers’ nutritional needs. These milks were fortified with iron sulfate stabilized with maltodextrin and citric acid. Methods: 15 women (33–47 years old) participated in study. They received on different days, after an overnight fast, 200 mL of Formula A; 200 mL of Formula B; 30 mL of a solution of iron and ascorbic acid as reference dose and 200 mL of full fat cow’s milk fortified with iron as ferrous sulfate. Milk formulas and reference dose were labeled with radioisotopes 59Fe or 55Fe, and the absorption of iron measured by erythrocyte incorporation of radioactive Fe. Results: The geometric mean iron absorption corrected to 40% of the reference dose was 20.6% for Formula A and 20.7% for Formula B, versus 7.5% of iron fortified cow’s milk (p < 0.001). The post hoc Sheffé indeed differences between the milk formulas and the cow’s milk (p < 0.001). Conclusion: Formulas A and B contain highly bioavailable iron, which contributes to covering toddlers’ requirements of this micronutrient. PMID:26529007

  18. Toxicity, bioavailability and pharmacokinetics of a newly formulated colistin sulfate solution.

    PubMed

    Lin, B; Zhang, C; Xiao, X

    2005-08-01

    We formulated a new colistin sulfate injectable solution and tested its effectiveness, toxicity and pharmacokinetics in vivo on mice, rabbits, and piglets. When intramuscularly injected (i.m.) into rabbits at 0.5 mL per site, the 2.5% colistin sulfate solution caused no reaction at the injection site, but the 5.0% solution caused the muscle circumference to appear erythematic. Tested LD50 in CD-1 mice were 38.72 mg/kg for i.m. and 431.95 mg/kg for oral administration, respectively. At 15.0 mg/kg/day (i.m.) for 5 days, colistin sulfate caused obvious neurotoxicity to piglets with moderate granular degenerations in the epithelial tissues from kidney and liver. These toxic responses were not seen when colistin sulfate was injected at 10.0 mg/kg/day for 5 days. Pharmacokinetic studies revealed Cmax of 3.73 +/- 0.28 and 6.40 +/- 0.18 microg/mL, Tmax of 32 +/- 1.5 and 34 +/- 1.8 min, t(1/2beta) of 256 +/- 14 and 264 +/- 29 min, and absolute bioavailability of 95.94 and 88.45% for colistin sulfate intramuscularly injected to piglets at 2.5 and 5.0 mg/kg, respectively. Serum colistin sulfate concentration followed a two-compartment open model showing first-order absorption. The high bioavailability and the long-lasting serum retention time indicated that the new solution is suitable for i.m. in piglets with a recommended dose of 2.5 mg/kg injected twice daily.

  19. Calcium sulfate crystallization along citrus root channels in a Florida soil exhibiting acid sulfate properties

    SciTech Connect

    Syslo, S.K.; Myhre, D.L.; Harris, W.G.

    1988-02-01

    The authors observed euhedral crystals in Manatee soil in a citrus grove in St. Lucie County, Florida. The material was identified as gypsum (CaSO/sub 4/ /times/ 2H/sub 2/O) using x-ray diffraction and infrared spectra. Photomicrography and scanning electron microscopy revealed that gypsum accumulated both in old root channels and within citrus root tissue of the Btg horizon. The subsurface horizons had elevated sulfate levels, a low initial pH, a drop (0.5 unit) in pH upon air-drying. Electrical conductivity paralleled the concentration of water-soluble sulfate. High levels of calcium and sulfate occurred for horizons above the water table. This accumulation is attributed to groundwater bearing these ions and subsequently discharging them to the overlying soil. Dead citrus roots appear to act as wicks to aid water transfer from lower to higher horizons. The roots and their empty channels provide spaces in which the gypsum can precipitate if the concentrations of calcium and sulfate in the evaporating groundwater exceed the solubility product of gypsum.

  20. 21 CFR 522.380 - Chloral hydrate, pentobarbital, and magnesium sulfate sterile aqueous solution.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... effect is produced. Cattle usually require a lower dosage on the basis of body weight. When used as a... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Chloral hydrate, pentobarbital, and magnesium sulfate sterile aqueous solution. 522.380 Section 522.380 Food and Drugs FOOD AND DRUG...

  1. 21 CFR 522.380 - Chloral hydrate, pentobarbital, and magnesium sulfate sterile aqueous solution.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... effect is produced. Cattle usually require a lower dosage on the basis of body weight. When used as a... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Chloral hydrate, pentobarbital, and magnesium sulfate sterile aqueous solution. 522.380 Section 522.380 Food and Drugs FOOD AND DRUG...

  2. 21 CFR 522.380 - Chloral hydrate, pentobarbital, and magnesium sulfate sterile aqueous solution.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... effect is produced. Cattle usually require a lower dosage on the basis of body weight. When used as a... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Chloral hydrate, pentobarbital, and magnesium sulfate sterile aqueous solution. 522.380 Section 522.380 Food and Drugs FOOD AND DRUG...

  3. Hydroxylation, conjugation and sulfation of bile acids in primary monolayer cultures of rat hepatocytes

    SciTech Connect

    Princen, H.M.; Meijer, P.

    1988-08-15

    Hydroxylation of lithocholic, chenodeoxycholic, deoxycholic and cholic acids was studied in monolayers of rat hepatocytes cultured for 76 h. The majority of added lithocholic and chenodeoxycholic acids was metabolized to beta-muricholic acid (56-76%). A small part of these bile acids (9%), however, and a considerable amount of deoxycholic and cholic acids (21%) were converted into metabolites more polar than cholic acid in the first culture period. Formation of these compounds decreased during the last day of culture. Bile acids synthesized after addition of (4-/sup 14/C)-cholesterol were almost entirely (97%) sulfated and/or conjugated, predominantly with taurine (54-66%), during culture. Sulfated bile acids were mainly composed of free bile acids. The ability of hepatocytes to sulfurylate bile acids declined with culture age. Thus, rat hepatocytes in primary monolayer culture are capable to sulfurylate bile acids and to hydroxylate trihydroxylated bile acids, suggesting formation of polyhydroxylated metabolites.

  4. Filtrates & Residues: A Convenient, Low-Cost Method for Determining Sulfate in Acid Rain.

    ERIC Educational Resources Information Center

    Johns, Nicholas; Longstaff, Stephen J.

    1987-01-01

    Describes efforts in devising a method for determining sulfate quickly and accurately from rainwater samples. Explains the design and operation of the apparatus and identifies the solutions for the testing. (ML)

  5. STATISTICAL VALIDATION OF SULFATE QUANTIFICATION METHODS USED FOR ANALYSIS OF ACID MINE DRAINAGE

    EPA Science Inventory

    Turbidimetric method (TM), ion chromatography (IC) and inductively coupled plasma atomic emission spectrometry (ICP-AES) with and without acid digestion have been compared and validated for the determination of sulfate in mining wastewater. Analytical methods were chosen to compa...

  6. Cerro Negro, Nicaragua: A Key Mars Analog Environment for Acid-Sulfate Weathering

    NASA Astrophysics Data System (ADS)

    Hynek, B. M.; Rogers, K. L.; McCollom, T. M.

    2007-07-01

    Cerro Negro Volcano, Nicaragua, is being investigated as an analog for acid-sulfate weathering of Mars-like basalts. Our goal is to better understand the mineral alteration pathways and the astrobiological potential of early Mars.

  7. Acid-Sulfate Weathering of Basalts at Cerro Negro Volcano, Nicaragua: An Early Mars Analog

    NASA Astrophysics Data System (ADS)

    Marcucci, E. C.; Hynek, B. M.; McCollom, T. M.; Rogers, K. L.

    2010-03-01

    Cerro Negro, Nicaragua is a high temperature, low pH, S-rich environment, proposed to explain some acid-sulfate weathering on Mars. Simultaneously, we are analyzing field samples, laboratory experiments, theoretical modeling, and microbial studies.

  8. Acid-Sulfate Weathering of Cerro Negro Basalt: An Early Mars Analog

    NASA Astrophysics Data System (ADS)

    Marcucci, E. C.; Hynek, B. M.; McCollom, T. M.

    2012-05-01

    Understanding the weathering in an acidic volcanic environment gives insights into paleoconditions that formed the sulfates we see on Mars today. A series of experiments and models show the main secondary minerals and controls on their formation.

  9. A study of crystal growth by solution technique. [triglycine sulfate single crystals

    NASA Technical Reports Server (NTRS)

    Lal, R. B.

    1979-01-01

    The advantages and mechanisms of crystal growth from solution are discussed as well as the effects of impurity adsorption on the kinetics of crystal growth. Uncertainities regarding crystal growth in a low gravity environment are examined. Single crystals of triglycine sulfate were grown using a low temperature solution technique. Small components were assembled and fabricated for future space flights. A space processing experiment proposal accepted by NASA for the Spacelab-3 mission is included.

  10. Preparation of manganese sulfate from low-grade manganese carbonate ores by sulfuric acid leaching

    NASA Astrophysics Data System (ADS)

    Lin, Qing-quan; Gu, Guo-hua; Wang, Hui; Zhu, Ren-feng; Liu, You-cai; Fu, Jian-gang

    2016-05-01

    In this study, a method for preparing pure manganese sulfate from low-grade ores with a granule mean size of 0.47 mm by direct acid leaching was developed. The effects of the types of leaching agents, sulfuric acid concentration, reaction temperature, and agitation rate on the leaching efficiency of manganese were investigated. We observed that sulfuric acid used as a leaching agent provides a similar leaching efficiency of manganese and superior selectivity against calcium compared to hydrochloric acid. The optimal leaching conditions in sulfuric acid media were determined; under the optimal conditions, the leaching efficiencies of Mn and Ca were 92.42% and 9.61%, respectively. Moreover, the kinetics of manganese leaching indicated that the leaching follows the diffusion-controlled model with an apparent activation energy of 12.28 kJ·mol-1. The purification conditions of the leaching solution were also discussed. The results show that manganese dioxide is a suitable oxidant of ferrous ions and sodium dimethyldithiocarbamate is an effective precipitant of heavy metals. Finally, through chemical analysis and X-ray diffraction analysis, the obtained product was determined to contain 98% of MnSO4·H2O.

  11. Solid/liquid phase diagram of the ammonium sulfate/glutaric acid/water system.

    PubMed

    Beyer, Keith D; Pearson, Christian S; Henningfield, Drew S

    2013-05-02

    We have studied the low temperature phase diagram and water activities of the ammonium sulfate/glutaric acid/water system using differential scanning calorimetry, infrared spectroscopy of thin films, and a new technique: differential scanning calorimetry-video microscopy. Using these techniques, we have determined that there is a temperature-dependent kinetic effect to the dissolution of glutaric acid in aqueous solution. We have mapped the solid/liquid ternary phase diagram, determined the water activities based on the freezing point depression, and determined the ice/glutaric acid phase boundary as well as the ternary eutectic composition and temperature. We have also modified our glutaric acid/water binary phase diagram previously published based on these new results. We compare our results for the ternary system to the predictions of the Extended AIM Aerosol Thermodynamics Model (E-AIM), and find good agreement for the ice melting points in the ice primary phase field of this system; however, significant differences were found with respect to phase boundaries, concentration and temperature of the ternary eutectic, and glutaric acid dissolution.

  12. Measuring the enthalpies of interaction between glycine, L-cysteine, glycylglycine, and sodium dodecyl sulfate in aqueous solutions

    NASA Astrophysics Data System (ADS)

    Badelin, V. G.; Mezhevoi, I. N.; Tyunina, E. Yu.

    2017-03-01

    Calorimetric measurements of enthalpies of solution Δsol H m for glycine, L-cysteine, and glycylglycine in aqueous solutions of sodium dodecyl sulfate (SDS) with concentrations of up to 0.05 mol kg-1 are made. Standard enthalpy of solution Δsol H 0 and enthalpy of transfer Δtr H 0 of the dipeptide from water into mixed solvent are calculated. The calculated enthalpy coefficients of paired interactions of amino acids and dipeptide with SDS prove to be positive. Hydrophobic interactions between the biomolecules and SDS are found to have a major impact on the enthalpies of interaction in the three-component systems under study, within the indicated range of concentrations.

  13. Eliminating aluminum toxicity in an acid sulfate soil for rice cultivation using plant growth promoting bacteria.

    PubMed

    Panhwar, Qurban Ali; Naher, Umme Aminun; Radziah, Othman; Shamshuddin, Jusop; Razi, Ismail Mohd

    2015-02-20

    Aluminum toxicity is widely considered as the most important limiting factor for plants growing in acid sulfate soils. A study was conducted in laboratory and in field to ameliorate Al toxicity using plant growth promoting bacteria (PGPB), ground magnesium limestone (GML) and ground basalt. Five-day-old rice seedlings were inoculated by Bacillus sp., Stenotrophomonas maltophila, Burkholderia thailandensis and Burkholderia seminalis and grown for 21 days in Hoagland solution (pH 4.0) at various Al concentrations (0, 50 and 100 μM). Toxicity symptoms in root and leaf were studied using scanning electron microscope. In the field, biofertilizer (PGPB), GML and basalt were applied (4 t·ha-1 each). Results showed that Al severely affected the growth of rice. At high concentrations, the root surface was ruptured, leading to cell collapse; however, no damages were observed in the PGPB inoculated seedlings. After 21 days of inoculation, solution pH increased to >6.0, while the control treatment remained same. Field study showed that the highest rice growth and yield were obtained in the bio-fertilizer and GML treatments. This study showed that Al toxicity was reduced by PGPB via production of organic acids that were able to chelate the Al and the production of polysaccharides that increased solution pH. The release of phytohormones further enhanced rice growth that resulted in yield increase.

  14. Homoserine as an Aspartic Acid Precursor for Synthesis of Proteoglycan Glycopeptide Containing Aspartic Acid and a Sulfated Glycan Chain.

    PubMed

    Yang, Weizhun; Ramadan, Sherif; Yang, Bo; Yoshida, Keisuke; Huang, Xuefei

    2016-12-02

    Among many hurdles in synthesizing proteoglycan glycopeptides, one challenge is the incorporation of aspartic acid in the peptide backbone and acid sensitive O-sulfated glycan chains. To overcome this, a new strategy was developed utilizing homoserine as an aspartic acid precursor. The conversion of homoserine to aspartic acid in the glycopeptide was successfully accomplished by late stage oxidation using (2,2,6,6-tetramethyl-piperidin-1-yl)oxyl (TEMPO) and bis(acetoxy)iodobenzene (BAIB). This is the first time that a glycopeptide containing aspartic acid and an O-sulfated glycan was synthesized.

  15. 75 FR 51055 - Propionic Acid and Salts, and Urea Sulfate; Registration Review Proposed Decisions; Notice of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-18

    ... AGENCY Propionic Acid and Salts, and Urea Sulfate; Registration Review Proposed Decisions; Notice of... availability of EPA's proposed registration review decisions for the pesticides propionic acid and salts, and... acid is a fungicide and bactericide that is used to control fungi and bacteria in stored hay and...

  16. Dielectric constants and electrical conductivities of sodium dodecyl sulfate in aqueous solutions

    SciTech Connect

    Abe, M.; Ogino, K.

    1981-03-01

    Dielectric properties of sodium dodecyl sulfate in aqueous solution have been studied. The dielectric constant and ac electrical conductivity were measured in the frequency range 30 Hz to 6 MHz. At lower frequencies, with increasing concentrations of sodium dodecyl sulfate, dielectric properties were greatly affected by polarization on the surfaces of the electrode, the so-called space charge polarization. ac electrical conductivities were dependent on the concentration of sodium dodecyl sulfate at all frequencies. The activation energies of dc electrical conduction were much larger in the molecular state than in the aggregation state. The radius of a spherical particle with an electric double layer could be calculated through the measurement of dielectric constant and dc electrical conductivity. 18 references.

  17. Laboratory Simulated Acid-Sulfate Weathering of Basaltic Materials: Implications for Formation of Sulfates at Meridiani Planum and Gusev Crater, Mars

    NASA Technical Reports Server (NTRS)

    Golden, D. C.; Ming, Douglas W.; Morris, Richard V.; Mertzman, A.

    2006-01-01

    Acid-sulfate weathering of basaltic materials is a candidate formation process for the sulfate-rich outcrops and rocks at the MER rover Opportunity and Spirit landing sites. To determine the style of acid-sulfate weathering on Mars, we weathered basaltic materials (olivine-rich glassy basaltic sand and plagioclase feldspar-rich basaltic tephra) in the laboratory under different oxidative, acid-sulfate conditions and characterized the alteration products. We investigated alteration by (1) sulfuric-acid vapor (acid fog), (2) three-step hydrothermal leaching treatment approximating an open system and (3) single-step hydrothermal batch treatment approximating a "closed system." In acid fog experiments, Al, Fe, and Ca sulfates and amorphous silica formed from plagioclase-rich tephra, and Mg and Ca sulfates and amorphous silica formed from the olivine-rich sands. In three-step leaching experiments, only amorphous Si formed from the plagioclase-rich basaltic tephra, and jarosite, Mg and Ca sulfates and amorphous silica formed from olivine-rich basaltic sand. Amorphous silica formed under single-step experiments for both starting materials. Based upon our experiments, jarosite formation in Meridiani outcrop is potential evidence for an open system acid-sulfate weathering regime. Waters rich in sulfuric acid percolated through basaltic sediment, dissolving basaltic phases (e.g., olivine) and forming jarosite, other sulfates, and iron oxides. Aqueous alteration of outcrops and rocks on the West Spur of the Columbia Hills may have occurred when vapors rich in SO2 from volcanic sources reacted with basaltic materials. Soluble ions from the host rock (e.g., olivine) reacted with S to form Ca-, Mg-, and other sulfates along with iron oxides and oxyhydroxides.

  18. Distribution of Thermophilic Acidophiles at Cerro Negro, Nicaragua, an Analog for Acid-Sulfate Weathering Environments on Early Mars

    NASA Astrophysics Data System (ADS)

    Rogers, K. L.; Stephenson, S.; McCollom, T. M.; Hynek, B. M.

    2010-04-01

    Cerro Negro, Nicaragua is an excellent terrestrial analog for putative acid-sulfate weathering systems on early Mars. Sulfur- and sulfate-reducing acidophiles are found throughout Cerro Negro and can further elucidate the habitability of early Mars.

  19. Influence of bicarbonate ions on the deterioration of mortar bars in sulfate solutions

    SciTech Connect

    Kunther, W.; Lothenbach, B.; Scrivener, K.

    2013-02-15

    This work investigates the influence of bicarbonate ions on the deterioration of cementitious material exposed to sulfate ions. Mortars based on a CEM I and on a CEM III/B cement were investigated. Experimental investigations were compared to thermodynamic modeling and phase characterization to understand the differences in deterioration. The presence of bicarbonate ions significantly reduced the expansion of the CEM I mortars. Thermodynamic modeling showed that at high concentrations of bicarbonate ettringite and gypsum become unstable. Microstructural characterization combined with information from thermodynamic modeling suggests that conditions of high supersaturation with respect to ettringite are unlikely in the samples exposed in solutions containing bicarbonate. Consequently, expansive forces are not generated by the crystallization pressure of ettringite. There was little expansion of the CEM III/B sample even in the sodium sulfate solution. In the bicarbonate solution this mortar showed a highly leached zone at the surface in which calcite was observed.

  20. Efflorescent sulfates from Baia Sprie mining area (Romania)--Acid mine drainage and climatological approach.

    PubMed

    Buzatu, Andrei; Dill, Harald G; Buzgar, Nicolae; Damian, Gheorghe; Maftei, Andreea Elena; Apopei, Andrei Ionuț

    2016-01-15

    The Baia Sprie epithermal system, a well-known deposit for its impressive mineralogical associations, shows the proper conditions for acid mine drainage and can be considered a general example for affected mining areas around the globe. Efflorescent samples from the abandoned open pit Minei Hill have been analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman and near-infrared (NIR) spectrometry. The identified phases represent mostly iron sulfates with different hydration degrees (szomolnokite, rozenite, melanterite, coquimbite, ferricopiapite), Zn and Al sulfates (gunningite, alunogen, halotrichite). The samples were heated at different temperatures in order to establish the phase transformations among the studied sulfates. The dehydration temperatures and intermediate phases upon decomposition were successfully identified for each of mineral phases. Gunningite was the single sulfate that showed no transformations during the heating experiment. All the other sulfates started to dehydrate within the 30-90 °C temperature range. The acid mine drainage is the main cause for sulfates formation, triggered by pyrite oxidation as the major source for the abundant iron sulfates. Based on the dehydration temperatures, the climatological interpretation indicated that melanterite formation and long-term presence is related to continental and temperate climates. Coquimbite and rozenite are attributed also to the dry arid/semi-arid areas, in addition to the above mentioned ones. The more stable sulfates, alunogen, halotrichite, szomolnokite, ferricopiapite and gunningite, can form and persists in all climate regimes, from dry continental to even tropical humid.

  1. A Solution-Based Approach for Mo-99 Production: Considerations for Nitrate versus Sulfate Media

    DOE PAGES

    Youker, Amanda J.; Chemerisov, Sergey D.; Kalensky, Michael; ...

    2013-01-01

    Molybdenum-99 is the parent of Technetium-99m, which is used in nearly 80% of all nuclear medicine procedures. The medical community has been plagued by Mo-99 shortages due to aging reactors, such as the NRU (National Research Universal) reactor in Canada. There are currently no US producers of Mo-99, and NRU is scheduled for shutdown in 2016, which means that another Mo-99 shortage is imminent unless a potential domestic Mo-99 producer fills the void. Argonne National Laboratory is assisting two potential domestic suppliers of Mo-99 by examining the effects of a uranyl nitrate versus a uranyl sulfate target solution configuration onmore » Mo-99 production. Uranyl nitrate solutions are easier to prepare and do not generate detectable amounts of peroxide upon irradiation, but a high radiation field can lead to a large increase in pH, which can lead to the precipitation of fission products and uranyl hydroxides. Uranyl sulfate solutions are more difficult to prepare, and enough peroxide is generated during irradiation to cause precipitation of uranyl peroxide, but this can be prevented by adding a catalyst to the solution. A titania sorbent can be used to recover Mo-99 from a highly concentrated uranyl nitrate or uranyl sulfate solution; however, different approaches must be taken to prevent precipitation during Mo-99 production.« less

  2. Arsenate immobilization associated with microbial oxidation of ferrous ion in complex acid sulfate water.

    PubMed

    Ma, Yingqun; Lin, Chuxia

    2012-05-30

    Chemical, XRD, SEM, RS, FTIR and XPS techniques were used to investigate arsenate immobilization associated with microbial Fe(2+) oxidation in a complex acid sulfate water system consisting of a modified 9 K solution (pH 2.0) plus As, Cu, Cd, Pb, Zn and Mn. At a 1:12.5:70 molar ratio of As:Fe:S, schweretmannite formation was impeded. This was in contrast with the predominant presence of schwertmannite when the heavy metals were absent, suggesting that a schwertmannite binding model is not valid for explaining arsenate immobilization in the complex system. In this study, arsenate was initially immobilized through co-precipitation with non-Fe metals and phosphate. Subsequently when sufficient Fe(3+) was produced from Fe(2+) oxidation, formation of a mixed iron, arsenate and phosphate phase predominated. The last stage involved surface complexation of arsenate species. Pb appeared to play an insignificant role in arsenate immobilization due to its strong affinity for sulfate to form anglesite. Phosphate strongly competed with arsenate for the available binding sites. However, As exhibited an increased capacity to compete with P and S for available binding sites from the co-precipitation to surface complexation stage. Adsorbed As tended to be in HAsO(4)(2-) form. The scavenged arsenate species was relatively stable after 2464-h aging.

  3. Formation of diphenylthioarsinic acid from diphenylarsinic acid under anaerobic sulfate-reducing soil conditions.

    PubMed

    Hisatomi, Shihoko; Guan, Ling; Nakajima, Mami; Fujii, Kunihiko; Nonaka, Masanori; Harada, Naoki

    2013-11-15

    Diphenylarsinic acid (DPAA) is a toxic phenylarsenical compound often found around sites contaminated with phenylarsenic chemical warfare agents, diphenylcyanoarsine or diphenylchloroarsine, which were buried in soil after the World Wars. This research concerns the elucidation of the chemical structure of an arsenic metabolite transformed from DPAA under anaerobic sulfate-reducing soil conditions. In LC/ICP-MS analysis, the retention time of the metabolite was identical to that of a major phenylarsenical compound synthesized by chemical reaction of DPAA and hydrogen sulfide. Moreover the mass spectra for the two compounds measured using LC/TOF-MS were similar. Subsequent high resolution mass spectral analysis indicated that two major ions at m/z 261 and 279, observed on both mass spectra, were attributable to C12H10AsS and C12H12AsSO, respectively. These findings strongly suggest that the latter ion is the molecular-related ion ([M+H](+)) of diphenylthioarsinic acid (DPTA; (C6H5)2AsS(OH)) and the former ion is its dehydrated fragment. Thus, our results reveal that DPAA can be transformed to DPTA, as a major metabolite, under sulfate-reducing soil conditions. Moreover, formation of diphenyldithioarsinic acid and subsequent dimerization were predicted by the chemical reaction analysis of DPAA with hydrogen sulfide. This is the first report to elucidate the occurrence of DPAA-thionation in an anaerobic soil.

  4. Deliquescence and crystallization of ammonium sulfate-glutaric acid and sodium chloride-glutaric acid particles

    NASA Astrophysics Data System (ADS)

    Pant, Atul; Fok, Abel; Parsons, Matthew T.; Mak, Jackson; Bertram, Allan K.

    2004-06-01

    In the following, we report the deliquescence relative humidities (DRH) and crystallization relative humidities (CRH) of mixed inorganic-organic particles, specifically ammonium sulfate-glutaric acid and sodium chloride-glutaric acid particles. Knowledge of the DRH and CRH of mixed inorganic-organic particles is crucial for predicting the role of aerosol particles in the atmosphere. Our DRH results are in good agreement with previous measurements, but our CRH results are significantly lower than some of the previous measurements reported in the literature. Our studies show that the DRH and CRH of ammonium sulfate and sodium chloride only decreased slightly when the mole fraction of the acid was less than 0.4. If other organics in the atmosphere behave in a similar manner, then the DRH and CRH of mixed inorganic-organic atmospheric particles will only be slightly less than the DRH and CRH of pure inorganic particles when the organic mole fraction is less than 0.4. Our results also show that if the particles contain a significant amount of organics (mole fraction > 0.5) the crystallization relative humidity decreases significantly and the particles are more likely to remain in the liquid state. Further work is needed to determine if other organics species of atmospheric importance have a similar effect.

  5. Sulfate Mineral Formation from Acid-Weathered Phyllosilicates: Implications for the Aqueous History of Mars

    NASA Technical Reports Server (NTRS)

    Craig, P. I.; Ming, D. W.; Rampe, E. B.; Morris, R. V.

    2015-01-01

    Phyllosilicates on Mars are thought to have formed under neutral to alkaline conditions during Mars' earliest Noachian geologic era (approx. 4.1-3.7 Gya). Sulfate formation, on the other hand, requires more acidic conditions which are thought to have occurred later during Mars' Hesperian era (approx. 3.7-3.0 Gya). Therefore, regions on Mars where phyllosilicates and sulfates are found in close proximity to each other provide evidence for the geologic and aqueous conditions during this global transition. Both phyllosilicates and sulfates form in the presence of water and thus give clues to the aqueous history of Mars and its potential for habitability. Phyllosilicates that formed during the Noachian era may have been weathered by the prevailing acidic conditions that characterize the Hesperian. Therefore, the purpose of this study is to characterize the alteration products resulting from acid-sulfate weathered phyllosilicates in laboratory experiments. This study focuses on two phyllosilicates commonly identified with sulfates on Mars: nontronite and saponite. We also compare our results to observations of phyllosilicates and sulfates on Mars to better understand the formation process of sulfates in close proximity to phyllosilicates on Mars and constrain the aqueous conditions of these regions on Mars.

  6. ELECTROLYTIC REDUCTION OF NITRIC ACID SOLUTIONS

    DOEpatents

    Alter, H.W.; Barney, D.L.

    1958-09-30

    A process is presented for the treatment of radioactivc waste nitric acid solutions. The nitric acid solution is neutralized with an alkali metal hydroxide in an amount sufficient to precipitate insoluble hydroxides, and after separation of the precipitate the solution is electrolyzed to convert the alkali nitrate formed, to alkali hydroxide, gaseous ammonla and oxygen. The solution is then reusable after reducing the volume by evaporating the water and dissolved ammonia.

  7. Nitric acid recovery from waste solutions

    DOEpatents

    Wilson, A. S.

    1959-04-14

    The recovery of nitric acid from aqueous nitrate solutions containing fission products as impurities is described. It is desirable to subject such solutions to concentration by evaporation since nitric acid is regenerated thereby. A difficulty, however, is that the highly radioactive fission product ruthenium is volatilized together with the nitric acid. It has been found that by adding nitrous acid, ruthenium volatilization is suppressed and reduced to a negligible degree so that the distillate obtained is practically free of ruthenium.

  8. Secondary sulfate minerals associated with acid drainage in the eastern US: Recycling of metals and acidity in surficial environments

    USGS Publications Warehouse

    Hammarstrom, J.M.; Seal, R.R.; Meier, A.L.; Kornfeld, J.M.

    2005-01-01

    Weathering of metal-sulfide minerals produces suites of variably soluble efflorescent sulfate salts at a number of localities in the eastern United States. The salts, which are present on mine wastes, tailings piles, and outcrops, include minerals that incorporate heavy metals in solid solution, primarily the highly soluble members of the melanterite, rozenite, epsomite, halotrichite, and copiapite groups. The minerals were identified by a combination of powder X-ray diffraction (XRD), scanning electron microscopy (SEM), and electron-microprobe. Base-metal salts are rare at these localities, and Cu, Zn, and Co are commonly sequestered as solid solutions within Fe- and Fe-Al sulfate minerals. Salt dissolution affects the surface-water chemistry at abandoned mines that exploited the massive sulfide deposits in the Vermont copper belt, the Mineral district of central Virginia, the Copper Basin (Ducktown) mining district of Tennessee, and where sulfide-bearing metamorphic rocks undisturbed by mining are exposed in Great Smoky Mountains National Park in North Carolina and Tennessee. Dissolution experiments on composite salt samples from three minesites and two outcrops of metamorphic rock showed that, in all cases, the pH of the leachates rapidly declined from 6.9 to 30 mg L-1), Fe (>47 mg L-1), sulfate (>1000 mg L-1), and base metals (>1000 mg L-1 for minesites, and 2 mg L-1 for other sites). Geochemical modeling of surface waters, mine-waste leachates, and salt leachates using PHREEQC software predicted saturation in the observed ochre minerals, but significant concentration by evaporation would be needed to reach saturation in most of the sulfate salts. Periodic surface-water monitoring at Vermont minesites indicated peak annual metal loads during spring runoff. At the Virginia site, where no winter-long snowpack develops, metal loads were highest during summer months when salts were dissolved periodically by rainstorms following sustained evaporation during dry

  9. On the relevance of volume increase for the length changes of mortar bars in sulfate solutions

    SciTech Connect

    Kunther, Wolfgang; Lothenbach, Barbara; Scrivener, Karen L.

    2013-04-01

    The ingress of sulfate ions into cementitious materials leads to the formation of ettringite, gypsum and other phases. The increase in solid volume through the formation of these phases is often assumed to be the only reason for expansion. In this paper we systematically compare the volume increase predicted by thermodynamic modeling to macroscopic expansion for mortars made with CEM I in different sulfate solutions and for mortars made with a range of blended cements in sodium sulfate solution. It is shown that the length changes cannot be explained by simple volume increase alone. A more plausible explanation of expansion lies in the theory of crystallization pressure, in which crystals forming from a supersaturated solution may exert pressure on their surroundings. It is observed that expansion occurs in systems where thermodynamic modeling predicts the co-existence of ettringite with gypsum. In such a case, if monosulfate and gypsum are both present locally, the solution can be highly supersaturated with respect to ettringite, whose formation in confined conditions (such as within C–S–H) can then exert expansive forces.

  10. Practical applications of sulfate-reducing bacteria to control acid mine drainage at the Lilly/Orphan Boy Mine near Elliston, Montana

    SciTech Connect

    Canty, M.

    1994-12-31

    The overall purpose of this document is to provide a detailed technical description of a technology, biological sulfate reduction, which is being demonstrated under the Mine Waste Technology Pilot Program, and provide the technology evaluation process undertaken to select this technology for demonstration. In addition, this document will link the use of the selected technology to an application at a specific site. The purpose of this project is to develop technical information on the ability of biological sulfate reduction to slow the process of acid generation and, thus, improve water quality at a remote mine site. Several technologies are screened for their potential to treat acid mine water and to function as a source control for a specific acid-generating situation: a mine shaft and associated underground workings flooded with acid mine water and discharging a small flow from a mine opening. The preferred technology is the use of biological sulfate reduction. Sulfate-reducing bacteria are capable of reducing sulfate to sulfide, as well as increasing the pH and alkalinity of water affected by acid generation. Soluble sulfide reacts with the soluble metals in solution to form insoluble metal sulfides. The environment needed for efficient sulfate-reducing bacteria growth decreases acid production by reducing the dissolved oxygen in water and increasing pH. A detailed technical description of the sulfate-reducing bacteria technology, based on an extensive review of the technical literature, is presented. The field demonstration of this technology to be performed at the Lilly/Orphan Boy Mine is also described. Finally, additional in situ applications of biological sulfate reduction are presented.

  11. High aerosol acidity despite declining atmospheric sulfate concentrations over the past 15 years

    NASA Astrophysics Data System (ADS)

    Weber, Rodney J.; Guo, Hongyu; Russell, Armistead G.; Nenes, Athanasios

    2016-04-01

    Particle acidity affects aerosol concentrations, chemical composition and toxicity. Sulfate is often the main acid component of aerosols, and largely determines the acidity of fine particles under 2.5 μm in diameter, PM2.5. Over the past 15 years, atmospheric sulfate concentrations in the southeastern United States have decreased by 70%, whereas ammonia concentrations have been steady. Similar trends are occurring in many regions globally. Aerosol ammonium nitrate concentrations were assumed to increase to compensate for decreasing sulfate, which would result from increasing neutrality. Here we use observed gas and aerosol composition, humidity, and temperature data collected at a rural southeastern US site in June and July 2013 (ref. ), and a thermodynamic model that predicts pH and the gas-particle equilibrium concentrations of inorganic species from the observations to show that PM2.5 at the site is acidic. pH buffering by partitioning of ammonia between the gas and particle phases produced a relatively constant particle pH of 0-2 throughout the 15 years of decreasing atmospheric sulfate concentrations, and little change in particle ammonium nitrate concentrations. We conclude that the reductions in aerosol acidity widely anticipated from sulfur reductions, and expected acidity-related health and climate benefits, are unlikely to occur until atmospheric sulfate concentrations reach near pre-anthropogenic levels.

  12. Treatment of acid mine drainage by sulfate reducing bacteria with iron in bench scale runs.

    PubMed

    Bai, He; Kang, Yong; Quan, Hongen; Han, Yang; Sun, Jiao; Feng, Ying

    2013-01-01

    In order to treat acid mine drainage (AMD) effectively using sulfate-reducing bacteria (SRB) at high concentration of sulfate and heavy metals, Fe(0) was added to enhance the activity of SRB. When AMD was treated by SRB and Fe(0) at 25 °C, more than 61% of sulfate was removed and the effluent pH was improved from 2.75 to 6.20 during the operation. Cu(2+) was removed effectively with the removal efficiency at 99%, while only 86% of Fe(2+) was removed during the AMD treatment, without conspicuous change of Mn(2+) in the effluent in the process.

  13. A stable solid acid material: Sulfated ZrO2 dispersed on alumina nanotubes

    NASA Astrophysics Data System (ADS)

    Feng, Yu; Jiaqi, Chen; Xu, Wang; Rui-Feng, Li

    2017-02-01

    A tubular solid acid catalyst was designed by loading sulfated zirconia into γ-Al2O3 nanotubes using the method of stepwise deposition. The XRD, N2 adsorption-desorption characterization demonstrated that introducing alumina nanotube and SO4 2- anions have played an important role in stabilizing the metastable tetragonal ZrO2 phase, and the sulfated zirconia on the surface of the γ-Al2O3 nanotube has high dispersion and stability. The catalyst reused repeatedly possesses large amounts of acid sites and good acidity, exhibiting high catalytic activity and stability for isopropylbenzene cracking.

  14. Reactive transport controls on sandy acid sulfate soils and impacts on shallow groundwater quality

    NASA Astrophysics Data System (ADS)

    Salmon, S. Ursula; Rate, Andrew W.; Rengel, Zed; Appleyard, Steven; Prommer, Henning; Hinz, Christoph

    2014-06-01

    Disturbance or drainage of potential acid sulfate soils (PASS) can result in the release of acidity and degradation of infrastructure, water resources, and the environment. Soil processes affecting shallow groundwater quality have been investigated using a numerical code that integrates (bio)geochemical processes with water, solute, and gas transport. The patterns of severe and persistent acidification (pH < 4) in the sandy, carbonate-depleted podzols of a coastal plain could be reproduced without calibration, based on oxidation of microcrystalline pyrite after groundwater level decrease and/or residual groundwater acidity, due to slow vertical solute transport rates. The rate of acidification was limited by gas phase diffusion of oxygen and hence was sensitive to soil water retention properties and in some cases also to oxygen consumption by organic matter mineralization. Despite diffusion limitation, the rate of oxidation in sandy soils was rapid once pyrite-bearing horizons were exposed, even to a depth of 7.5 m. Groundwater level movement was thus identified as an important control on acidification, as well as the initial pyrite content. Increase in the rate of Fe(II) oxidation lead to slightly lower pH and greater accumulation of Fe(III) phases, but had little effect on the overall amount of pyrite oxidized. Aluminosilicate (kaolinite) dissolution had a small pH-buffering effect but lead to the release of Al and associated acidity. Simulated dewatering scenarios highlighted the potential of the model for risk assessment of (bio)geochemical impacts on soil and groundwater over a range of temporal and spatial scales.

  15. Solution nonideality related to solute molecular characteristics of amino acids.

    PubMed Central

    Keener, C R; Fullerton, G D; Cameron, I L; Xiong, J

    1995-01-01

    By measuring the freezing-point depression for dilute, aqueous solutions of all water-soluble amino acids, we test the hypothesis that nonideality in aqueous solutions is due to solute-induced water structuring near hydrophobic surfaces and solute-induced water destructuring in the dipolar electric fields generated by the solute. Nonideality is expressed with a single solute/solvent interaction parameter I, calculated from experimental measure of delta T. A related parameter, I(n), gives a method of directly relating solute characteristics to solute-induced water structuring or destructuring. I(n)-values correlate directly with hydrophobic surface area and inversely with dipolar strength. By comparing the nonideality of amino acids with progressively larger hydrophobic side chains, structuring is shown to increase with hydrophobic surface area at a rate of one perturbed water molecule per 8.8 square angstroms, implying monolayer coverage. Destructuring is attributed to dielectric realignment as described by the Debye-Hückel theory, but with a constant separation of charges in the amino-carboxyl dipole. By using dimers and trimers of glycine and alanine, this destructuring is shown to increase with increasing dipole strength using increased separation of fixed dipolar charges. The capacity to predict nonideal solution behavior on the basis of amino acid characteristics will permit prediction of free energy of transfer to water, which may help predict the energetics of folding and unfolding of proteins based on the characteristics of constituent amino acids. Images FIGURE 6 PMID:7711253

  16. Acidic and total primary sulfates: development of emission factors for major stationary combustion sources

    SciTech Connect

    Goklany, I.M.; Hoffnagle, G.F.; Brackbill, E.A.

    1984-01-01

    ''Best estimates'' of emission factors for major sources of acidic and total primary sulfates are developed for use in the compilation of emission inventories for the eastern U.S. These may, in turn, be used for modeling of acidic or sulfate deposition. The factors are based upon a critical evaluation of the generic measurement methods used to quantify total and acidic primary sulfate emissions, and an exhaustive review and critique of individual papers and studies available in the open literature which present measurement data on primary sulfate emissions. It develops a qualitative rating scheme which specifies the level of confidence that should be attached to the emission factor determinations. The paper concludes that much of the existing data on primary sulfates from stationary combustion sources are, probably, significantly biased upward and, therefore, inappropriate for the derivation of emission factors. Therefore, existing estimates of primary sulfate emissions for these source categories are, probably, substanitally inflated. It also concludes that, for most source categories, very little confidence can be attached to the best estimates because of the paucity of data obtained from measurement techniques which are likely to be free of systematic bias. 68 references.

  17. Insights Into the Aqueous History of Mars from Acid-Sulfate Weathered Phyllosilicates

    NASA Technical Reports Server (NTRS)

    Craig, P. I.; Ming, D. W.; Rampe, E. B.; Morris, R. V.

    2016-01-01

    Phyllosilicates on Mars are thought to have formed during Mars' earliest Noachian geologic era (approx. 4.1-3.7 Ga). Sulfate formation, on the other hand, requires more acidic conditions which are thought to have occurred later during Mars' Hesperian era (approx. 3.7-3.0 Ga). Therefore, regions on Mars where phyllosilicates and sulfates are found in close proximity to each other provide evidence for the aqueous conditions during this global transition. Both phyllosilicates and sulfates form in the presence of water and thus give clues to the aqueous history of Mars and its potential for habitability. Phyllosilicates that formed during the Noachian era would have been weathered by the prevailing acidic conditions that define the Hesperian. Therefore, the purpose of this study is to characterize the alteration products of acid-sulfate weathered phyllosilicates in laboratory experiments, focusing on the Fe/Mg-smectites commonly identified on Mars. We also compare our results to observations of phyllosilicates and sulfates on Mars in regions such as Endeavour Crater and Mawrth Vallis to understand the formation process of sulfates and constrain the aqueous history of these regions.

  18. Desorption behavior of zinc atoms from zinc-sulfate solution irradiated with pulsed DC plasma

    NASA Astrophysics Data System (ADS)

    Takaba, Takafumi; Suzuki, Haruka; Toyoda, Hirotaka

    2016-07-01

    A DC pulsed plasma ignited between a metal needle and zinc sulfate (ZnSO4) solution electrode was used to investigate Zn metal desorption from an electrolyte solution. Using an ICCD camera and optical band-pass filter, 2D atomic absorption spectroscopy was carried out during irradiation of pulsed plasma to the surface of the solution. The time-resolved measurement of Zn atoms released to the gas phase revealed that the Zn desorption rate monotonically increased with increasing number of discharge repetitions. The surface temperature of the electrolyte solution was observed with a thermographic camera, and correlations between the H2O and Zn desorption rate were inspected. The correlation between the H2O and Zn desorption rate suggested that Zn desorption is assisted not only by the electric field of the discharge but also by H2O evaporating from the solution.

  19. Sulfate Formation From Acid-Weathered Phylosilicates: Implications for the Aqueous History of Mars

    NASA Technical Reports Server (NTRS)

    Craig, P. I.; Ming, D. W.; Rampe, E. B.

    2014-01-01

    Most phyllosilicates on Mars are thought to have formed during the planet's earliest Noachian era, then Mars underwent a global change making the planet's surface more acidic [e.g. 1]. Prevailing acidic conditions may have affected the already existing phyllosilicates, resulting in the formation of sulfates. Both sulfates and phyllosilicates have been identified on Mars in a variety of geologic settings [2] but only in a handful of sites are these minerals found in close spatial proximity to each other, including Mawrth Vallis [3,4] and Gale Crater [5]. While sulfate formation from the acidic weathering of basalts is well documented in the literature [6,7], few experimental studies investigate sulfate formation from acid-weathered phyllosilicates [8-10]. The purpose of this study is to characterize the al-teration products of acid-weathered phyllosilicates in laboratory experiments. We focus on three commonly identified phyllosilicates on Mars: nontronite (Fe-smectite), saponite (Mg-smectite), and montmorillonite (Al-smectite) [1, and references therein]. This information will help constrain the formation processes of sulfates observed in close association with phyllosilicates on Mars and provide a better understanding of the aqueous history of such regions as well as the planet as a whole.

  20. Sodium Sulfate Separation from Aqueous Alkaline Solutions via Crystalline Urea-Functionalized Capsules: Thermodynamics and Kinetics of Crystallization

    DOE PAGES

    Custelcean, Radu; Sloop, Frederick V.; Rajbanshi, Arbin; ...

    2014-12-04

    We measured the thermodynamics and kinetics of crystallization of sodium sulfate with a tripodal tris-urea receptor (L1) from aqueous alkaline solutions in the 15 55 C temperature range, with the goal of identifying the optimal conditions for efficient and quick sulfate removal from nuclear wastes. The use of radiolabeled Na235SO4 provided a practical way to monitor the sulfate concentration in solution by liquid scintillation counting. Our results are consistent with a two-step crystallization mechanism, involving relatively quick dissolution of crystalline L1 followed by the rate-limiting crystallization of the Na2SO4(L1)2(H2O)4 capsules. We found that temperature exerted relatively little influence over themore » equilibrium sulfate concentration, which ranged between 0.004 and 0.011 M. Moreover, this corresponds to 77 91% removal of sulfate from a solution containing 0.0475 M initial sulfate concentration, as found in a typical Hanford waste tank. The apparent pseudo-first-order rate constant for sulfate removal increased 20-fold from 15 to 55 C, corresponding to an activation energy of 14.1 kcal/mol. At the highest measured temperature of 55 C, 63% and 75% of sulfate was removed from solution within 8 h and 24 h, respectively.« less

  1. Sodium Sulfate Separation from Aqueous Alkaline Solutions via Crystalline Urea-Functionalized Capsules: Thermodynamics and Kinetics of Crystallization

    SciTech Connect

    Custelcean, Radu; Sloop, Frederick V.; Rajbanshi, Arbin; Wan, Shun; Moyer, Bruce A.

    2014-12-04

    We measured the thermodynamics and kinetics of crystallization of sodium sulfate with a tripodal tris-urea receptor (L1) from aqueous alkaline solutions in the 15 55 C temperature range, with the goal of identifying the optimal conditions for efficient and quick sulfate removal from nuclear wastes. The use of radiolabeled Na235SO4 provided a practical way to monitor the sulfate concentration in solution by liquid scintillation counting. Our results are consistent with a two-step crystallization mechanism, involving relatively quick dissolution of crystalline L1 followed by the rate-limiting crystallization of the Na2SO4(L1)2(H2O)4 capsules. We found that temperature exerted relatively little influence over the equilibrium sulfate concentration, which ranged between 0.004 and 0.011 M. Moreover, this corresponds to 77 91% removal of sulfate from a solution containing 0.0475 M initial sulfate concentration, as found in a typical Hanford waste tank. The apparent pseudo-first-order rate constant for sulfate removal increased 20-fold from 15 to 55 C, corresponding to an activation energy of 14.1 kcal/mol. At the highest measured temperature of 55 C, 63% and 75% of sulfate was removed from solution within 8 h and 24 h, respectively.

  2. 21 CFR 184.1443 - Magnesium sulfate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Magnesium sulfate. 184.1443 Section 184.1443 Food... Specific Substances Affirmed as GRAS § 184.1443 Magnesium sulfate. (a) Magnesium sulfate (MgSO4·7H2O, CAS... magnesium oxide, hydroxide, or carbonate with sulfuric acid and evaporating the solution to...

  3. 21 CFR 184.1443 - Magnesium sulfate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Magnesium sulfate. 184.1443 Section 184.1443 Food... Specific Substances Affirmed as GRAS § 184.1443 Magnesium sulfate. (a) Magnesium sulfate (MgSO4·7H2O, CAS... magnesium oxide, hydroxide, or carbonate with sulfuric acid and evaporating the solution to...

  4. 21 CFR 184.1443 - Magnesium sulfate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Magnesium sulfate. 184.1443 Section 184.1443 Food... Specific Substances Affirmed as GRAS § 184.1443 Magnesium sulfate. (a) Magnesium sulfate (MgSO4·7H2O, CAS... magnesium oxide, hydroxide, or carbonate with sulfuric acid and evaporating the solution to...

  5. 21 CFR 184.1443 - Magnesium sulfate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Magnesium sulfate. 184.1443 Section 184.1443 Food... Specific Substances Affirmed as GRAS § 184.1443 Magnesium sulfate. (a) Magnesium sulfate (MgSO4·7H2O, CAS... magnesium oxide, hydroxide, or carbonate with sulfuric acid and evaporating the solution to...

  6. Recovery of pyruvic acid from biotransformation solutions.

    PubMed

    Ma, C Q; Li, J C; Qiu, J H; Wang, M; Xu, P

    2006-04-01

    The aim of this investigation was to separate pyruvic acid of biotransformation solutions from lactic acid through complex extraction. For this purpose, complex extraction was investigated from model solutions. Tri-n-octanylamine (TOA) was used as the extractant. The effects of various diluents, the stoichiometry of pyruvic acid to TOA, and the initial pH of the aqueous phase on the extraction process were investigated in this study. The effects of sodium hydroxide (NaOH) and trimethylamine (TMA) on the back extraction process were also studied, respectively. The optimal conditions attained from the model solutions proved efficient on the biotransformation solutions of different concentrations. A total recovery of 71-82% of pyruvic acid was obtained, whereas 89-92% of lactic acid was removed. The purity of pyruvic acid reached 97% after the removal of TMA by a simple distillation.

  7. Solution growth of Triglycine Sulfate (TGS) crystals on the International Microgravity Laboratory (IML-1)

    NASA Technical Reports Server (NTRS)

    Lal, Ravi B.; Batra, Ashok K.; Yang, LI; Wilcox, W. R.; Trolinger, J. D.

    1989-01-01

    An experiment was planned for the International Microgravity Laboratory (IML-1) to be launched around Feb. 1991. Crystals of triglycine sulfate (TGS) will be grown by low temperature solution crystal growth technique using a multiuser facility called Fluid Experiment System (FES). A special cooled sting technique of solution crystal growth will be used where heat is extracted from the seed crystal through a semi-insulating sting, thereby creating the desired supersaturation near the growing crystal. Also, a holocamera will be used to provide tomography of the three dimensional flow field and particle image displacement velocimetry to monitor the convective flows.

  8. Identifying sources of acidity and spatial distribution of acid sulfate soils in the Anglesea River catchment, southern Australia

    NASA Astrophysics Data System (ADS)

    Wong, Vanessa; Yau, Chin; Kennedy, David

    2015-04-01

    Globally, coastal and estuarine floodplains are frequently underlain by sulfidic sediments. When exposed to oxygen, sulfidic sediments oxidise to form acid sulfate soils, adversely impacting on floodplain health and adjacent aquatic ecoystems. In eastern Australia, our understanding of the formation of these coastal and estuarine floodplains, and hence, spatial distribution of acid sulfate soils, is relatively well established. These soils have largely formed as a result of sedimentation of coastal river valleys approximately 6000 years BP when sea levels were one to two metres higher. However, our understanding of the evolution of estuarine systems and acid sulfate soil formation, and hence, distribution, in southern Australia remains limited. The Anglesea River, in southern Australia, is subjected to frequent episodes of poor water quality and low pH resulting in closure of the river and, in extreme cases, large fish kill events. This region is heavily reliant on tourism and host to a number of iconic features, including the Great Ocean Road and Twelve Apostles. Poor water quality has been linked to acid leakage from mining activities and Tertiary-aged coal seams, peat swamps and acid sulfate soils in the region. However, our understanding of the sources of acidity and distribution of acid sulfate soils in this region remains poor. In this study, four sites on the Anglesea River floodplain were sampled, representative of the main vegetation communities. Peat swamps and intertidal marshes were both significant sources of acidity on the floodplain in the lower catchment. However, acid neutralising capacity provided by carbonate sands suggests that there are additional sources of acidity higher in the catchment. This pilot study has highlighted the complexity in the links between the floodplain, upper catchment and waterways with further research required to understand these links for targeted acid management strategies.

  9. Sulfate scale dissolution

    SciTech Connect

    Morris, R.L.; Paul, J.M.

    1992-01-28

    This patent describes a method for removing barium sulfate scale. It comprises contacting the scale with an aqueous solution having a pH of about 8 to about 14 and consisting essentially of a chelating agent comprising a polyaminopolycarboxylic acid or salt of such an acid in a concentration of 0.1 to 1.0 M, and anions of a monocarboxylic acid selected form mercaptoacetic acid, hydroxyacetic acid, aminoacetic acid, or salicyclic acid in a concentration of 0.1 to 1.0 M and which is soluble in the solution under the selected pH conditions, to dissolve the scale.

  10. Optical Properties of Internally Mixed Aerosol Particles Composed of Dicarboxylic Acids and Ammonium Sulfate

    NASA Astrophysics Data System (ADS)

    Freedman, Miriam A.; Hasenkopf, Christa A.; Beaver, Melinda R.; Tolbert, Margaret A.

    2009-10-01

    We have investigated the optical properties of internally mixed aerosol particles composed of dicarboxylic acids and ammonium sulfate using cavity ring-down aerosol extinction spectroscopy at a wavelength of 532 nm. The real refractive indices of these nonabsorbing species were retrieved from the extinction and concentration of the particles using Mie scattering theory. We obtain refractive indices for pure ammonium sulfate and pure dicarboxylic acids that are consistent with literature values, where they exist, to within experimental error. For mixed particles, however, our data deviates significantly from a volume-weighted average of the pure components. Surprisingly, the real refractive indices of internal mixtures of succinic acid and ammonium sulfate are higher than either of the pure components at the highest organic weight fractions. For binary internal mixtures of oxalic or adipic acid with ammonium sulfate, the real refractive indices of the mixtures are approximately the same as ammonium sulfate for all organic weight fractions. Various optical mixing rules for homogeneous and slightly heterogeneous systems fail to explain the experimental real refractive indices. It is likely that complex particle morphologies are responsible for the observed behavior of the mixed particles. Implications of our results for atmospheric modeling and aerosol structure are discussed.

  11. Production of fired construction brick from high sulfate-containing fly ash with boric acid addition.

    PubMed

    Başpinar, M Serhat; Kahraman, Erhan; Görhan, Gökhan; Demir, Ismail

    2010-01-01

    The increase of power plant capacity has led to the production of an increasing amount of fly ash that causes high environmental impact in Turkey. Some of the fly ash is utilized within the fired brick industry but high sulfate-containing fly ash creates severe problems during sintering of the fired brick. This study attempted to investigate the potential for converting high sulfate-containing fly ash into useful material for the construction industry by the addition of boric acid. The chemical and mineralogical composition of fly ash and clay were investigated. Boric acid (H(3)BO(3)) was added to fly ash-clay mixtures with up to 5 wt.%. Six different series of test samples were produced by uniaxial pressing. The samples were fired at the industrial clay-brick firing temperatures of 800, 900 and 1000 degrees C. The microstructures of the fired samples were investigated by scanning electron microscopy and some physical and mechanical properties were measured. It was concluded that the firing at conventional brick firing temperature of high sulfate fly ash without any addition of boric acid resulted in very weak strength bricks. The addition of boric acid and clay simultaneously to the high sulfate- containing fly ash brick dramatically increased the compressive strength of the samples at a firing temperature of 1000 degrees C by modifying the sintering behaviour of high sulfate fly ash.

  12. Formation of hexamethylenetetramine by aqueous solutions of formaldehyde and ammonium sulfate

    NASA Astrophysics Data System (ADS)

    Rodriguez, A. A.; De Haan, D. O.; Kua, J.

    2012-12-01

    Formaldehyde and ammonium sulfate are prominent compounds found in cloudwater. Electronic structure calculations and lab experiments were carried out to explore the oligomerization reactions between formaldehyde and ammonia. Density functional theory calculations along with solvation and thermodynamic corrections were performed to map the kinetic and thermodynamic landscape for the reactions leading to the formation of hexamethylenetetramine (hmta). Three general classes of reactions were considered: nucleophilic addition of amine to formaldehyde, nucleophilic addition of ammonia to imine intermediates ammonia, and dehydration of alkanolamines. The reaction was studied experimentally using bulk-phase aqueous solutions of formaldehyde, ammonium sulfate, and in some experiments, iron (III) sulfate (chosen because Fe3+ forms a brown complex with hmta). Aqueous standard solutions of the reaction product hmta were also made. Reaction mixtures were analyzed using NMR, UV-Vis spectroscopy and LCMS. Compound hmta was the main product observed by both NMR and LCMS. Using LCMS a large peak was observed within minutes of mixing the reactants. The absorbance of the reaction mixture increased strongly below 225 nm but little to no absorbance was observed in the visible spectrum.

  13. Inhibition of sulfate-reducing bacteria by metal sulfide formation in bioremediation of acid mine drainage.

    PubMed

    Utgikar, Vivek P; Harmon, Stephen M; Chaudhary, Navendu; Tabak, Henry H; Govind, Rakesh; Haines, John R

    2002-02-01

    Acid mine drainage (AMD) containing high concentrations of sulfate and heavy metal ions can be treated by biological sulfate reduction. It has been reported that the effect of heavy metals on sulfate-reducing bacteria (SRB) can be stimulatory at lower concentrations and toxic/inhibitory at higher concentrations. The quantification of the toxic/inhibitory effect of dissolved heavy metals is critical for the design and operation of an effective AMD bioremediation process. Serum bottle and batch reactor studies on metal toxicity to SRB indicate that insoluble metal sulfides can inhibit the SRB activity as well. The mechanism of inhibition is postulated to be external to the bacterial cell. The experimental data indicate that the metal sulfides formed due to the reaction between the dissolved metal and biogenic sulfide act as barriers preventing the access of the reactants (sulfate, organic matter) to the necessary enzymes. Scanning electron micrographs of the SRB cultures exposed to copper and zinc provide supporting evidence for this hypothesis. The SRB cultures retained their ability to effect sulfate reduction indicating that the metal sulfides were not lethally toxic to the SRB. This phenomenon of metal sulfide inhibition of the SRB has to be taken into account while designing a sulfate-reducing bioreator, and subsequently an efficient biotreatment strategy for AMD. Any metal sulfide formed in the bioreactor needs to be removed immediately from the system to maintain the efficiency of the process of sulfate reduction.

  14. Experimental Results for Direct Electron Irradiation of a Uranyl Sulfate Solution: Bubble Formation and Thermal Hydraulics Studies

    SciTech Connect

    Chemerisov, Sergey; Gromov, R.; Makarashvili, Vakhtang; Heltemes, Thad; Sun, Zaijing; Wardle, Kent E.; Bailey, James; Stepinski, Dominique; Jerden, James; Vandegrift, George F.

    2015-01-30

    In support of the development of accelerator-driven production of fission product Mo-99 as proposed by SHINE Medical Technologies, a 35 MeV electron linac was used to irradiate depleted-uranium (DU) uranyl sulfate dissolved in pH 1 sulfuric acid at average power densities of 6 kW, 12 kW, and 15 kW. During these irradiations, gas bubbles were generated in the solution due to the radiolytic decomposition of water molecules in the solution. Multiple video cameras were used to record the behavior of bubble generation and transport in the solution. Seven six-channel thermocouples were used to record temperature gradients in the solution from self-heating. Measurements of hydrogen and oxygen concentrations in a helium sweep gas were recorded by a gas chromatograph to estimate production rates during irradiation. These data are being used to validate a computational fluid dynamics (CFD) model of the experiment that includes multiphase flow and a custom bubble injection model for the solution region.

  15. Microbial biofilms control economic metal mobility in an acid-sulfate hydrothermal system

    NASA Astrophysics Data System (ADS)

    Phillips-Lander, C. M.; Roberts, J. A.; Hernandez, W.; Mora, M.; Fowle, D. A.

    2012-12-01

    Trace metal cycling in hydrothermal systems has been the subject of a variety of geochemical and economical geology studies. Typically in these settings these elements are sequestered in sulfide and oxide mineral fractions, however in near-surface low-temperature environments organic matter and microorganisms (typically in mats) have been implicated in their mobility through sorption. Here we specifically examine the role of microbial biofilms on metal partitioning in an acid-sulfate hydrothermal system. We studied the influence of microorganisms and microbial biofilms on trace metal adsorption in Pailas de Aguas I, an acid-sulfate hot spring on the southwest flank of Rincon de la Vieja, a composite stratovolcano in the Guanacaste Province, Costa Rica. Spring waters contain high suspended loads, and are characterized by high T (79.6-89.3oC), low pH (2.6-4), and high ionic strengths (I= 0.5-0.8). Waters contain high concentrations of the biogeochemically active elements Fe (4-6 mmol/l) and SO42- (38 mmol/l), but PO43- are below detection limits (bdl). Silver, Ni, and Mo concentrations are bdl; however other trace metals are present in solution in concentrations of 0.1-0.2 mg/l Cd, 0.2-0.4 mg/l Cr and V, 0.04-1 mg/l Cu,. Preliminary 16S rRNA analyses of microorganisms in sediments reveal several species of algae, including Galderia sp., Cyanidium sp, γ-proteobacteria, Acidithiobacillus caldus, Euryarcheota, and methanogens. To evaluate microbial biofilms' impact on trace metal mobility we analyzed a combination of suspended, bulk and biofilm associated sediment samples via X-ray diffraction (XRD) and trace element sequential extractions (SE). XRD analysis indicated all samples were primarily composed of Fe/Al clay minerals (nontronite, kaolinite), 2- and 6-line ferrihydrite, goethite, and hematite, quartz, and opal-α. SE showed the highest concentrations of Cu, Mo, and V were found in the suspended load. Molybdenum was found primarily in the residual and organic

  16. Partial crystallization and deliquescence of particles containing ammonium sulfate and dicarboxylic acids

    NASA Astrophysics Data System (ADS)

    Ling, Tsz Yan; Chan, Chak K.

    2008-07-01

    The partial crystallization and deliquescence of ammonium sulfate (AS) particles internally mixed with malonic acid (MA), glutaric acid (GA), and succinic acid (SA) were studied. Hygroscopic properties, elastic light scattering, and Raman spectra were measured during water uptake and evaporation of single particles suspended in an electrodynamic balance. AS/MA particles remained partially crystallized at RHs as low as 16%, while AS/GA and AS/SA particles became completely dry at about 30-36% RH and below. Partial deliquescence was observed at intermediate RHs of <10% to 79%, 70% to 80%, and 80% to >90% for the AS/MA, AS/GA, and AS/SA particles, respectively. Solid inclusions in various amounts were in equilibrium with the aqueous solutions. The Raman spectra show solid inclusions of both AS and MA in AS/MA particles, suggesting the heterogeneous crystallization of MA on solid AS. AS was found to deliquesce first at 76% RH in the AS/GA system, followed by GA at 78% RH. In the SA/AS system, AS was observed to dissolve at 80% RH, while SA remained as solid for RH as high as 90%. Comparisons to the thermodynamic model E-AIM demonstrated the necessity to correctly predict the solid phase during partial deliquescence for accurate water content estimation. The Raman spectra also revealed the formation of metastable forms of organic acids upon crystallization from supersaturated droplets of AS/GA and AS/SA. Transformation of metastable solids to stable forms was observed before water uptake in the AS/GA particles, while the SA in AS/SA particles transformed in the presence of water.

  17. Impacts of Sulfate Seed Acidity and Water Content on Isoprene Secondary Organic Aerosol Formation.

    PubMed

    Wong, Jenny P S; Lee, Alex K Y; Abbatt, Jonathan P D

    2015-11-17

    The effects of particle-phase water and the acidity of pre-existing sulfate seed particles on the formation of isoprene secondary organic aerosol (SOA) was investigated. SOA was generated from the photo-oxidation of isoprene in a flow tube reactor at 70% relative humidity (RH) and room temperature in the presence of three different sulfate seeds (effloresced and deliquesced ammonium sulfate and ammonium bisulfate) under low NOx conditions. High OH exposure conditions lead to little isoprene epoxydiol (IEPOX) SOA being generated. The primary result is that particle-phase water had the largest effect on the amount of SOA formed, with 60% more SOA formation occurring with deliquesced ammonium sulfate seeds as compared to that on effloresced ones. The additional organic material was highly oxidized. Although the amount of SOA formed did not exhibit a dependence on the range of seed particle acidity examined, perhaps because of the low amount of IEPOX SOA, the levels of high-molecular-weight material increased with acidity. While the uptake of organics was partially reversible under drying, the results nevertheless indicate that particle-phase water enhanced the amount of organic aerosol material formed and that the RH cycling of sulfate particles may mediate the extent of isoprene SOA formation in the atmosphere.

  18. NIR spectroscopic properties of aqueous acids solutions.

    PubMed

    Omar, Ahmad Fairuz; Atan, Hanafi; Matjafri, Mohd Zubir

    2012-06-15

    Acid content is one of the important quality attributes in determining the maturity index of agricultural product, particularly fruits. Despite the fact that much research on the measurement of acidity in fruits through non-destructive spectroscopy analysis at NIR wavelengths between 700 to 1,000 nm has been conducted, the same response towards individual acids is not well known. This paper presents NIR spectroscopy analysis on aqueous citric, tartaric, malic and oxalic solutions through quantitative analysis by selecting a set of wavelengths that can best be used to measure the pH of the solutions. The aquaphotomics study of the acid solutions has generated R² above 0.9 for the measurement of all acids. The most important wavelengths for pH are located at 918-925 nm and 990-996 nm, while at 975 nm for water.

  19. Algae as an electron donor promoting sulfate reduction for the bioremediation of acid rock drainage.

    PubMed

    Ayala-Parra, Pedro; Sierra-Alvarez, Reyes; Field, Jim A

    2016-11-05

    This study assessed bioremediation of acid rock drainage in simulated permeable reactive barriers (PRB) using algae, Chlorella sorokiniana, as the sole electron donor for sulfate-reducing bacteria. Lipid extracted algae (LEA), the residues of biodiesel production, were compared with whole cell algae (WCA) as an electron donor to promote sulfate-reducing activity. Inoculated columns containing anaerobic granular sludge were fed a synthetic medium containing H2SO4 and Cu(2+). Sulfate, sulfide, Cu(2+) and pH were monitored throughout the experiment of 123d. Cu recovered in the column packing at the end of the experiment was evaluated using sequential extraction. Both WCA and LEA promoted 80% of sulfate removal (12.7mg SO4(2-) d(-1)) enabling near complete Cu removal (>99.5%) and alkalinity generation raising the effluent pH to 6.5. No noteworthy sulfate reduction, alkalinity formation and Cu(2+) removal were observed in the endogenous control. In algae amended-columns, Cu(2+) was precipitated with biogenic H2S produced by sulfate reduction. Formation of CuS was evidenced by sequential extraction and X-ray diffraction. LEA and WCA provided similar levels of electron donor based on the COD balance. The results demonstrate an innovative passive remediation system using residual algae biomass from the biodiesel industry.

  20. Immobilizing U from solution by immobilized sulfate-reducing bacteria of desulfovibrio desulfuricans

    NASA Astrophysics Data System (ADS)

    Xu, Hulfang; Barton, Larry L.

    2000-07-01

    As determined by transmission electron microscopy, the reduction of uranyl accetate by immobilized cells of Desulfovibrio desulfuricans results in the production of black uraninite nanocrystals precipitated outside the cell. Some nanocrystals are associated with outer membranes of the cell as revealed from cross sections of these metabolically active sulfate-reducing bacteria. The nanocrystals have an average diameter of 5 nm and have anhedral shape. It is proposed that cytochrome in these cells has an important role in the reduction of uranyl through transferring electron from molecular hydrogen or lactic acid to uranyl ions.

  1. The Solution Structure of Heparan Sulfate Differs from That of Heparin

    PubMed Central

    Khan, Sanaullah; Rodriguez, Elizabeth; Patel, Rima; Gor, Jayesh; Mulloy, Barbara; Perkins, Stephen J.

    2011-01-01

    The highly sulfated polysaccharides heparin and heparan sulfate (HS) play key roles in the regulation of physiological and pathophysiological processes. Despite its importance, no molecular structures of free HS have been reported up to now. By combining analytical ultracentrifugation, small angle x-ray scattering, and constrained scattering modeling recently used for heparin, we have analyzed the solution structures for eight purified HS fragments degree of polymerization 6–18 (dp6–dp18) and dp24, corresponding to the predominantly unsulfated GlcA-GlcNAc domains of heparan sulfate. Unlike heparin, the sedimentation coefficient s20,w of HS dp6–dp24 showed a small rotor speed dependence, where similar s20,w values of 0.82–1.26 S (absorbance optics) and 1.05–1.34 S (interference optics) were determined. The corresponding x-ray scattering measurements of HS dp6–dp24 gave radius of gyration (RG) values from 1.03 to 2.82 nm, cross-sectional radius of gyration (RXS) values from 0.31 to 0.65 nm, and maximum lengths (L) from 3.0 to 10.0 nm. These data showed that HS has a longer and more bent structure than heparin. Constrained scattering modeling starting from 5000–8000 conformationally randomized HS structures gave best fit dp6–dp16 molecular structures that were longer and more bent than their equivalents in heparin. No fits were obtained for HS dp18 or dp24, indicating their higher flexibility. We conclude that HS displays an extended bent conformation that is significantly distinct from that for heparin. The difference is attributed to the different predominant monosaccharide sequence and reduced sulfation of HS, indicating that HS may interact differently with proteins compared with heparin. PMID:21576246

  2. The Solution Structure of Heparan Sulfate Differs from That of Heparin

    PubMed Central

    Khan, Sanaullah; Fung, Ka Wai; Rodriguez, Elizabeth; Patel, Rima; Gor, Jayesh; Mulloy, Barbara; Perkins, Stephen J.

    2013-01-01

    The highly sulfated polysaccharides heparin and heparan sulfate (HS) play key roles in the regulation of physiological and pathophysiological processes. Despite its importance, no molecular structures of free HS have been reported up to now. By combining analytical ultracentrifugation, small angle x-ray scattering, and constrained scattering modeling recently used for heparin, we have analyzed the solution structures for eight purified HS fragments dp6–dp24 corresponding to the predominantly unsulfated GlcA-GlcNAc domains of heparan sulfate. Unlike heparin, the sedimentation coefficient s20,w of HS dp6–dp24 showed a small rotor speed dependence, where similar s20,w values of 0.82–1.26 S (absorbance optics) and 1.05–1.34 S (interference optics) were determined. The corresponding x-ray scattering measurements of HS dp6–dp24 gave radii of gyration RG values from 1.03 to 2.82 nm, cross-sectional radii of gyration RXS values from 0.31 to 0.65 nm, and maximum lengths L from 3.0 to 10.0 nm. These data showed that HS has a longer and more bent structure than heparin. Constrained scattering modeling starting from 5,000 to 12,000 conformationally randomized HS structures gave best fit dp6–dp24 molecular structures that were longer and more bent than their equivalents in heparin. Alternative fits were obtained for HS dp18 and dp24, indicating their higher bending and flexibility. We conclude that HS displays bent conformations that are significantly distinct from that for heparin. The difference is attributed to the different predominant monosaccharide sequence and reduced sulfation of HS, indicating that HS may interact differently with proteins compared with heparin. PMID:23921391

  3. TOTAL PARTICLE, SULFATE, AND ACIDIC AEROSOL EMISSIONS FROM KEROSENE SPACE HEATERS

    EPA Science Inventory

    Chamber studies were conducted on four unvented kerosene space heaters to assess emissions of total particle, sulfate, and acidic aerosol. The heaters tested represented four burner designs currently in use by the public. Kerosene space heaters are a potential source of fine part...

  4. The effect of copper sulfate, potassium permanganate, and peracetic acid on Ichthyobodo necator in channel catfish

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ichthyobodo necator is a single celled biflagellate that can cause significant mortalities in fish, particularly young, tank-reared fish. Copper sulfate (CuSO4), potassium permanganate (KMnO4) and peracetic acid (PAA) were evaluated for effectiveness against Ichthybodosis in juvenile channel catfis...

  5. 40 CFR 417.130 - Applicability; description of the chlorosulfonic acid sulfation subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 30 2012-07-01 2012-07-01 false Applicability; description of the chlorosulfonic acid sulfation subcategory. 417.130 Section 417.130 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS SOAP AND DETERGENT MANUFACTURING POINT...

  6. 40 CFR 417.130 - Applicability; description of the chlorosulfonic acid sulfation subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 29 2014-07-01 2012-07-01 true Applicability; description of the chlorosulfonic acid sulfation subcategory. 417.130 Section 417.130 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS SOAP AND DETERGENT MANUFACTURING POINT...

  7. 40 CFR 417.120 - Applicability; description of the sulfamic acid sulfation subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 30 2013-07-01 2012-07-01 true Applicability; description of the sulfamic acid sulfation subcategory. 417.120 Section 417.120 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS SOAP AND DETERGENT MANUFACTURING POINT...

  8. 40 CFR 417.120 - Applicability; description of the sulfamic acid sulfation subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 30 2012-07-01 2012-07-01 false Applicability; description of the sulfamic acid sulfation subcategory. 417.120 Section 417.120 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS SOAP AND DETERGENT MANUFACTURING POINT...

  9. 40 CFR 417.120 - Applicability; description of the sulfamic acid sulfation subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 29 2014-07-01 2012-07-01 true Applicability; description of the sulfamic acid sulfation subcategory. 417.120 Section 417.120 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS SOAP AND DETERGENT MANUFACTURING POINT...

  10. 40 CFR 417.130 - Applicability; description of the chlorosulfonic acid sulfation subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 30 2013-07-01 2012-07-01 true Applicability; description of the chlorosulfonic acid sulfation subcategory. 417.130 Section 417.130 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS SOAP AND DETERGENT MANUFACTURING POINT...

  11. Mine Waste Technology Program. In Situ Source Control Of Acid Generation Using Sulfate-Reducing Bacteria

    EPA Science Inventory

    This report summarizes the results of the Mine Waste Technology Program (MWTP) Activity III, Project 3, In Situ Source Control of Acid Generation Using Sulfate-Reducing Bacteria, funded by the U.S. Environmental Protection Agency (EPA) and jointly administered by EPA and the U.S....

  12. Use of copper sulfate and peracetic acid as therapeutants on fish: can these replace formalin?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Copper sulfate (CuSO4) and peracetic acid (PAA) are compounds that have been found to be useful in several areas of aquaculture around the world. In the United States, CuSO4 is used for treatment of an ectoparasite (Ichthyophthirius multifiliis) on fish (Straus 1993; Tieman and Goodwin 2001), and s...

  13. Sulfate influx on band 3 protein of equine erythrocyte membrane (Equus caballus) using different experimental temperatures and buffer solutions.

    PubMed

    Casella, S; Piccione, D; Ielati, S; Bocchino, E G; Piccione, G

    2013-06-01

    The aim of this study was to assess the anion transport in equine erythrocytes through the measurement of the sulfate uptake operating from band 3 using different experimental temperatures and buffer solutions. Blood samples of six clinically healthy horses were collected via jugular vein puncture, and an emochrome-citometric examination was performed. The blood was divided into four aliquots and by centrifugation and aspiration the plasma and buffy coat were carefully discarded. The red blood cells were washed with an isosmotic medium and centrifuged. The obtained cell suspensions were incubated with two different experimental buffer solutions (buffer A: 115 mM Na2SO4, 10 mM NaCl, 20 mM ethylenediaminetetraacetic acid, 30 mM glucose; and buffer B: 115 mM Na2SO4, 10 mM NaCl, 20 mM ethylenediaminetetraacetic acid, 30 mM MgCl2) in a water bath for 1 h at 25 °C and 37 °C. Normal erythrocytes, suspended at 3% hematocrit, were used to measure the SO4= influx by absorption spectrophotometry at 425 nm wavelength. Unpaired Student's t-test showed a statistically significant decrease (P < 0.01) of rate constants in equine erythrocytes at 25 °C versus 37 °C using both experimental buffer solutions. Comparing the buffer A with buffer B unpaired Student's t-test showed statistically lower values (P < 0.0001) for A solution versus B solution both at 25 °C and at 37 °C. The greater inhibition of SO4 (=) influx measured in equine erythrocytes indicates the increased formation of the sulfydryl bonds in band 3 and the modulation of the sulfydryl groups, culminating in the conformational changes in band 3.

  14. Solid/liquid phase diagram of the ammonium sulfate/succinic acid/water system.

    PubMed

    Pearson, Christian S; Beyer, Keith D

    2015-05-14

    We have studied the low-temperature phase diagram and water activities of the ammonium sulfate/succinic acid/water system using differential scanning calorimetry and infrared spectroscopy of thin films. Using the results from our experiments, we have mapped the solid/liquid ternary phase diagram, determined the water activities based on the freezing point depression, and determined the ice/succinic acid phase boundary as well as the ternary eutectic composition and temperature. We also compared our results to the predictions of the extended AIM aerosol thermodynamics model (E-AIM) and found good agreement for the ice melting points in the ice primary phase field of this system; however, differences were found with respect to succinic acid solubility temperatures. We also compared the results of this study with those of previous studies that we have published on ammonium sulfate/dicarboxylic acid/water systems.

  15. Enhanced rosmarinic acid production by Lavandula vera MM cell suspension culture through elicitation with vanadyl sulfate.

    PubMed

    Georgiev, Milen; Kuzeva, Sonya; Pavlov, Atanas; Kovacheva, Elena; Ilieva, Mladenka

    2006-01-01

    The influence of elicitation on rosmarinic acid biosynthesis by Lavandula vera MM cell suspension culture was investigated using vanadyl sulfate as an abiotic elicitor. It was established that 12 h after treatment with 25 mg/l vanadyl sulfate the rosmarinic acid production was increased up to 3.92 g/l (2.8 times higher compared to the control cultivation). No significant amounts of rosmarinic acid were detected in the culture medium in comparison with its intracellular content. However, it was observed that the extracellular content of rosmarinic acid is 3.3 times higher compared to the control variant (4 h after treatment at elicitor concentration 25 mg/l).

  16. Methanol Uptake By Low Temperature Aqueous Sulfuric Acid Solutions

    NASA Technical Reports Server (NTRS)

    Iraci, Laura T.; Essin, Andrew M.; Golden, David M.; Hipskind, R. Stephen (Technical Monitor)

    2001-01-01

    To evaluate the role of upper tropospheric and lower stratospheric aerosols in the global budget of methanol, the solubility and reactivity of CH3OH in aqueous sulfuric acid solutions are under investigation. Using standard uptake techniques in a Knudsen cell reactor, we have measured the effective Henry's law coefficient, H(*), for methanol dissolution into 45 to 70 percent by weight H2SO4. We find that methanol solubility ranges from 10(exp 5) to 10(exp 8) M/atm and increases with decreasing temperature and with increasing sulfuric acid content. These solubility measurements include uptake due to physical solvation and all rapid equilibria which are established in solution. Our data indicate that simple uptake by aqueous sulfuric acid particles will not be a significant sink for methanol in the UT/LS. These results differ from those recently reported in the literature, and an explanation of this disparity will be presented. In addition to solvation, reaction between primary alcohols and sulfuric acid does occur, leading to the production of alkyl sulfates. Literature values for the rate of this reaction suggest that formation of CH3OSO3H may proceed in the atmosphere but is not significant under our experimental conditions. Results obtained using a complementary equilibrium measurement technique confirm this directly. In addition, the extent of methanol sequestration via formation of mono- and dimethylsulfate will be evaluated under several atmospheric conditions.

  17. Heterogeneous Chemistry of HONO on Liquid Sulfuric Acid: A New Mechanism of Chlorine Activation on Stratospheric Sulfate Aerosols

    NASA Technical Reports Server (NTRS)

    Zhang, Renyi; Leu, Ming-Taun; Keyser, Leon F.

    1996-01-01

    Heterogeneous chemistry of nitrous acid (HONO) on liquid sulfuric acid (H2SO4) Was investigated at conditions that prevail in the stratosphere. The measured uptake coefficient (gamma) of HONO on H2SO4 increased with increasing acid content, ranging from 0.03 for 65 wt % to about 0.1 for 74 wt %. In the aqueous phase, HONO underwent irreversible reaction with H2SO4 to form nitrosylsulfuric acid (NO(+)HSO4(-). At temperatures below 230 K, NO(+)HSO4(-) was observed to be stable and accumulated in concentrated solutions (less than 70 wt % H2SO4) but was unstable and quickly regenerated HONO in dilute solutions (less than 70 wt %). HCl reacted with HONO dissolved in sulfuric acid, releasing gaseous nitrosyl chloride (ClNO). The reaction probability between HCl and HONO varied from 0.01 to 0.02 for 60-72 wt % H2SO4. In the stratosphere, ClNO photodissociates rapidly to yield atomic chlorine, which catalytically destroys ozone. Analysis of the laboratory data reveals that the reaction of HCl with HONO on sulfate aerosols can affect stratospheric ozone balance during elevated sulfuric acid loadings after volcanic eruptions or due to emissions from the projected high-speed civil transport (HSCT). The present results may have important implications on the assessment of environmental acceptability of HSCT.

  18. Reference electrode for strong oxidizing acid solutions

    DOEpatents

    Rigdon, Lester P.; Harrar, Jackson E.; Bullock, Sr., Jack C.; McGuire, Raymond R.

    1990-01-01

    A reference electrode for the measurement of the oxidation-reduction potentials of solutions is especially suitable for oxidizing solutions such as highly concentrated and fuming nitric acids, the solutions of nitrogen oxides, N.sub.2 O.sub.4 and N.sub.2 O.sub.5, in nitric acids. The reference electrode is fabricated of entirely inert materials, has a half cell of Pt/Ce(IV)/Ce(III)/70 wt. % HNO.sub.3, and includes a double-junction design with an intermediate solution of 70 wt. % HNO.sub.3. The liquid junctions are made from Corning No. 7930 glass for low resistance and negligible solution leakage.

  19. Dielectric properties of solutions of oil materials solubilized by sodium dodecyl sulfate in aqueous solutions

    SciTech Connect

    Abe, M.; Shimizu, A.; Ogino, K.

    1982-08-01

    One of the most important properties of micellar systems is their ability to solubilize a variety of species. For aqueous micelles, solubilization is related closely to the hydrophobic and hydrophilic properties of the solubilizate. Different sites of solubilization and orientations may be involved, depending on the structure of the solubilizate. A number of studies on solubilization have been performed experimentally and theoretically. Dielectric constant measurement has proved to be a powerful tool for the investigation of permanent dipole moments of various molecules and of the behavior in solution of various substances, and has been applied in various fields. This technique has been used to determine the chemical structure of surfactants, but not to investigate the solubilization of oily materials in aqueous solution. The dielectric constants and ac electric conductivities observed when a solubilizate is added to an aqueous solution of an anionic surfactant and the differences in the solubilizing behavior due to different kinds of polar groups are discussed. 30 references.

  20. Viscosity of liquid ferric sulfate solutions and application to the formation of gullies on Mars

    NASA Astrophysics Data System (ADS)

    Chevrier, Vincent F.; Ulrich, Richard; Altheide, Travis S.

    2009-06-01

    We studied the viscosity of ferric sulfate Fe2(SO4)3 solutions as a model for low-temperature liquids on the surface of Mars and their implication in the formation of gullies. Viscosity varies with temperature and concentration, ranging from 7.0 × 10-3 Pa s for 38.8 wt % at 285.15 K to 4.6 Pa s for 58.2 wt % at 260.15 K. Using the experimental results, we built a semiempirical equation of viscosity as a function of temperature and salt concentration, which was combined with a numerical model to estimate the effect of these solutions on the formation of gullies. Calculated fluid velocities ranged from 0.5 to 14 m s-1, in accordance with estimates from image analyses. Turbulent flow occurs in the majority of the conditions and is characterized by a constant velocity (˜8.5 m s-1). At very low temperature and high concentration, the laminar regime shows reduced velocities (down to ˜0.5 m s-1). In between, a transitional regime presents high velocities, up to 14 m s-1. Using the velocities, we determined the size threshold for boulders to be moved by the liquid flow. Depending on the regime, boulders of diameter inferior to 3 m (turbulent), 4 m (transition), and down to 0.5 m (laminar) are displaced. Since laminar flow occurs only in an extremely limited range of conditions, for low temperatures (<240 K) and supersaturated solutions, the abundance of small boulders (˜0.5 m) in gully channels requires lower velocities and higher viscosities than ferric sulfate solution or any other water-based liquid can reach. This suggests an important participation of debris mixed with the liquid phase.

  1. Sulfate radical-induced degradation of Acid Orange 7 by a new magnetic composite catalyzed peroxymonosulfate oxidation process.

    PubMed

    Chen, Dan; Ma, Xiaolong; Zhou, Jizhi; Chen, Xi; Qian, Guangren

    2014-08-30

    We synthesized a novel magnetic composite, Fe3O4/Cu(Ni)Cr-LDH, as a heterogeneous catalyst for the degradation of organic dyes in the solution using sulfate radical-based advanced oxidation processes. The physicochemical properties of the composite synthesized via two-step microwave hydrothermal method were characterized by several techniques, such as X-ray diffraction (XRD), inductively coupled plasma (ICP), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). The degradation tests were performed at 25°C with Acid Orange 7 (AO7) initial concentration of 25mg/L and AO7/peroxymonosulfate (PMS) molar ratio of 1:10, which showed that the complete degradation by Fe3O4/Cu1.5Ni0.5Cr-LDH could be achieved and the mineralization rate could reach 46%. PMS was activated by Cu (II) and Fe (II/III) of Fe3O4/Cu(Ni)Cr-LDH to generate sulfate radicals (SO4(-)). Subsequently, the organic functional groups of AO7 molecules were destroyed by sulfate radicals (SO4(-)), inducing the degradation of AO7. Moreover, the catalytic behavior of the catalysts could be reused five times. Therefore, our work suggested that the Fe3O4/Cu(Ni)Cr-LDH composite could be applied widely for the treatment of organic dyes in wastewater.

  2. The influence of ferrous sulfate utilization on the sugar yields from dilute-acid pretreatment of softwood for bioethanol production.

    PubMed

    Monavari, Sanam; Galbe, Mats; Zacchi, Guido

    2011-01-01

    By employing metal salts in dilute-acid pretreatment the severity can be reduced due to reduced activation energy. This study reports on a dilute-acid steam pretreatment of spruce chips by addition of a small amount of ferrous sulfate to the acid catalyst, i.e., either SO2, H2SO3 or H2SO4. The utilization of ferrous sulfate resulted in a slightly increased overall glucose yield (from 74% to 78% of the theoretical value) in pretreatment with SO2 and H2SO3. Impregnation with ferrous sulfate and sulfuric acid did not give any improvement compared with pretreatment based solely on H2SO4.

  3. Pulmonary effects of acid sulfate inhalation in the guinea pig

    SciTech Connect

    Silbaugh, S.A.; Mauderly, J.L.; Wolff, R.K.; Carpenter, R.L.; Brownstein, D.G.; Harkema, J.R.; Rothenberg, S.J.

    1982-07-01

    Guinea pigs were exposed by inhalation for 1 to 8 hours to sulfuric acid aerosols of various sizes and concentrations in order to provide quantitative information for standards setting. The effects of sulfuric acid aerosols were examined to determine acute mortality, changes in respiratory function and morphology, response mechanisms, differences in individual sensitivity and changes in airway response to bronchoconstrictors. An aerosol generator for another sulfur-containing pollutant, ammonium bisulfite, was developed for use in animal exposures. Also, lung lesions which simulate human emphysema were produced by intratracheal elastase instillation to investigate a potential impaired animal model for sulfur pollutant exposures. Pulmonary mechanics, lung morphology, and histamine sensitivity data all suggest that the guinea pig reacts to sulfuric acid aerosols with a nearly all-or-none airway constrictive response. Results also indicate that the concentration at which this response occurs is affected by aerosol size, exposure profile and individual animal sensitivity. No acute pulmonary function changes were noted at concentrations below 15 mg/m/sup 3/. The reason for these differences is unknown.

  4. Solid/Liquid phase diagram of the ammonium sulfate/maleic acid/water system.

    PubMed

    Beyer, Keith D; Schroeder, Jason R; Pearson, Christian S

    2011-12-01

    We have studied the low temperature phase diagram and water activities of the ammonium sulfate/maleic acid/water system using differential scanning calorimetry and infrared spectroscopy of thin films. Using the results from our experiments, we have mapped the solid/liquid ternary phase diagram, determined the water activities based on the freezing point depression, and determined the ice/maleic acid phase boundary as well as the ternary eutectic composition and temperature. We also compare our results to the predictions of the extended AIM aerosol thermodynamics model and find good agreement for the ice melting points in the ice primary phase field of this system; however significant differences were found with respect to phase boundaries, maleic acid dissolution, and ammonium sulfate dissolution.

  5. Infrared spectroscopic study of the effect of oleic acid on the deliquescence behaviour of ammonium sulfate aerosol particles.

    PubMed

    Nájera, Juan J; Horn, Andrew B

    2009-01-21

    In order to accurately assess the impact of fatty acids on the hygroscopic properties of atmospheric aerosol particles, (NH4)2SO4 (ammonium sulfate) and oleic acid (cis-9-octadecenoic acid) were chosen to perform this study as components of the particle phase. Micron-sized (700-900 nm) particles containing (NH4)2SO4 and oleic acid were generated by nebulising aqueous solutions of (NH4)2SO4 and sodium oleate. In this study, the effect of oleic acid on the deliquescence phase transition of particles was investigated in a room temperature aerosol flow tube (AFT) system using Fourier transform infrared (FTIR) spectroscopy. Particles morphologies and their chemical compositions were also analysed using a variety of techniques, including attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy and scanning electron microscopy/energy dispersive X-ray analysis (SEM/EDX). The deliquescence relative humidity (DRH) of the (NH4)2SO4 component, determined at 81+/-2%, was slightly lowered or not affected by the presence of different thickness of oleic acid (21 nm, 44 nm and 109 nm) present in the particles. Analyses of the results presented here are consistent with earlier studies about the possible effects of water-insoluble fatty acids coatings on the phase transitions of atmospheric aerosol particles.

  6. Comparison of sodium acid sulfate to citric acid to inhibit browning of fresh-cut potatoes.

    PubMed

    Calder, Beth L; Kash, Emily A; Davis-Dentici, Katherine; Bushway, Alfred A

    2011-04-01

    Sodium acid sulfate (SAS) dip treatments were evaluated against a distilled water control and citric acid (CA) to compare its effectiveness in reducing enzymatic browning of raw, French-fry cut potatoes. Two separate studies were conducted with dip concentrations ranging from 0%, 1%, and 3% in experiment 1 to 0%, 2%, and 2.5% in experiment 2 to determine optimal dip concentrations. Russet Burbank potatoes were peeled, sliced, and dipped for 1 min and stored at 3 °C. Color, texture, fry surface pH, and microbiological analyses were conducted on days 0, 7, and 14. The 3% SAS- and CA-treated samples had significantly (p<0.0001) lower pH levels on fry surfaces than all other treatments. Both acidulants had significantly (p≤0.05) lower aerobic plate counts compared to controls in both studies by day 7. However, SAS appeared to be the most effective at the 3% level in maintaining a light fry color up to day 14 and had the highest L-values than all other treatments. The 3% SAS-treated fry slices appeared to have the least change in textural properties over storage time, having a significantly (p=0.0002) higher force value (kg force [kgf]) than the other treatments during experiment 1, without any signs of case-hardening that appeared in the control and CA-treated samples. SAS was just as comparable to CA in reducing surface fry pH and also lowering microbial counts over storage time. According to the results, SAS may be another viable acidulant to be utilized in the fresh-cut fruit and vegetable industry.

  7. Real-time investigations of Pt(111) surface transformations in sulfuric acid solutions.

    PubMed

    Braunschweig, Björn; Mukherjee, Prabuddha; Dlott, Dana D; Wieckowski, Andrzej

    2010-10-13

    We present the first broadband sum-frequency generation (SFG) spectra of adlayers from sulfuric acid solutions on Pt(111) surfaces and reveal surface transformations of (bi)sulfate anions in unprecedented detail. SFG amplitudes, bandwidth, and electrochemical Stark tuning of (bi)sulfate vibrational bands centered at 1250-1290 cm(-1) strongly depend on the applied potential and are correlated with prominent voltammetric features. (Bi)sulfate adlayers on Pt(111) are important model systems for weak, specific adsorption of anions on catalytically active surfaces. Although the existence of surface transformations on Pt(111) in dilute H(2)SO(4) solutions has been established by previous studies, so far they have not been observed with surface vibrational spectroscopy. Our results confirm previous reports of a surface transformation at 0.21 V and provide new information on a second transformation at 0.5 V due to surface hydroxyl formation and rearrangement of the electric double layer.

  8. Analysis of partitioning of organic compounds and proteins in aqueous polyethylene glycol-sodium sulfate aqueous two-phase systems in terms of solute-solvent interactions.

    PubMed

    da Silva, Nuno R; Ferreira, Luisa A; Madeira, Pedro P; Teixeira, José A; Uversky, Vladimir N; Zaslavsky, Boris Y

    2015-10-09

    Partition behavior of nine small organic compounds and six proteins was examined in poly(ethylene glycol)-8000-sodium sulfate aqueous two-phase systems containing 0.5M osmolyte (sorbitol, sucrose, trehalose, TMAO) and poly(ethylene glycol)-10000-sodium sulfate system, all in 0.01M sodium phosphate buffer, pH 6.8. The differences between the solvent properties of the coexisting phases (solvent dipolarity/polarizability, hydrogen bond donor acidity, and hydrogen bond acceptor basicity) were characterized with solvatochromic dyes using the solvatochromic comparison method. Differences between the electrostatic properties of the phases were determined by analysis of partitioning of sodium salts of dinitrophenylated (DNP-) amino acids with aliphatic alkyl side-chain. It was found out that the partition coefficient of all compounds examined (including proteins) may be described in terms of solute-solvent interactions. The results obtained in the study show that solute-solvent interactions of nonionic organic compounds and proteins in polyethylene glycol-sodium sulfate aqueous two-phase system differ from those in polyethylene glycol-dextran system.

  9. Influence of semi-batch operation on the precipitation of natrojarosite particles from sulfate solutions

    NASA Astrophysics Data System (ADS)

    Sandré, Anne-Laure; Gaunand, Alain

    2012-03-01

    The precipitation of natrojarosite from iron sodium sulfate solutions has been investigated at temperatures close to the atmospheric boiling point, in batch and semi-batch conditions. Semi-batch conditions make it possible to maintain a weaker iron concentration in the stirred reactor, leading to lower supersaturations, closer to those in continuous and possibly seeded MSMPRs or tanks—in series units. In these reactors, primary and secondary nucleations are few, allowing the growth of pure mono-crystalline particles of controlled size and size dispersion. Both modi operandi lead to agglomerates made of crystals of cubic habit. The surface of cauliflower-like particles from the batch modus operandi displays overlaying crystals, of size between 100 and 400 nm. The particles from the semi-batch mode, with moderate iron addition, are rougher and show bigger intergrown constitutive crystals of size up to a few microns, which denotes lesser secondary nucleation and more growth. A model is developed to characterize iron(III) and sulfate speciation with non-ideal behavior in the mother solution. It is used to compare the variations of supersaturation in the reactor between the batch and the semi-batch conditions. During the first 500 min, the supersaturation resulting from a moderate addition of iron is 10,000-10 times lower than during batch kinetics, which agrees with the reduction of secondary nucleation suggested by scanning electron micrographs. The semi-batch technique, which can be combined with the addition of support particles, is worth further work, aiming to reduce secondary nucleation and to determine the crystallite growth rate expression of natrojarosite as a function of supersaturation, using the model of solution developed in this work.

  10. Sulfated diesters of okadaic acid and DTX-1: Self-protective precursors of diarrhetic shellfish poisoning (DSP) toxins.

    PubMed

    Hu, Tingmo; LeBlanc, Patricia; Burton, Ian W; Walter, John A; McCarron, Pearse; Melanson, Jeremy E; Strangman, Wendy K; Wright, Jeffrey L C

    2017-03-01

    Many toxic secondary metabolites used for defense are also toxic to the producing organism. One important way to circumvent toxicity is to store the toxin as an inactive precursor. Several sulfated diesters of the diarrhetic shellfish poisoning (DSP) toxin okadaic acid have been reported from cultures of various dinoflagellate species belonging to the genus Prorocentrum. It has been proposed that these sulfated diesters are a means of toxin storage within the dinoflagellate cell, and that a putative enzyme mediated two-step hydrolysis of sulfated diesters such as DTX-4 and DTX-5 initially leads to the formation of diol esters and ultimately to the release of free okadaic acid. However, only one diol ester and no sulfated diesters of DTX-1, a closely related DSP toxin, have been isolated leading some to speculate that this toxin is not stored as a sulfated diester and is processed by some other means. DSP components in organic extracts of two large scale Prorocentrum lima laboratory cultures have been investigated. In addition to the usual suite of okadaic acid esters, as well as the free acids okadaic acid and DTX-1, a group of corresponding diol- and sulfated diesters of both okadaic acid and DTX-1 have now been isolated and structurally characterized, confirming that both okadaic acid and DTX-1 are initially formed in the dinoflagellate cell as the non-toxic sulfated diesters.

  11. Sulfation of metal-organic framework: Opportunities for acid catalysis and proton conductivity

    SciTech Connect

    Goesten, M.G.; Stavitski, E.; Juan-Alcaniz, J.; Ramos-Fernandez, E.V.; Sai Sankar Gupta, K.B.; van Bekkum, H.; Gascon, J. and Kapteijn, F.

    2011-05-24

    A new post-functionalization method for metal-organic frameworks (MOFs) has been developed to introduce acidity for catalysis. Upon treatment with a mixture of triflic anhydride and sulfuric acid, chemically stable MOF structures MIL-101(Cr) and MIL-53(Al) can be sulfated, resulting in a Broensted sulfoxy acid group attached to up to 50% of the aromatic terephthalate linkers of the structure. The sulfated samples have been extensively characterized by solid-state NMR, XANES, and FTIR spectroscopy. The functionalized acidic frameworks show catalytic activity similar to that of acidic polymers like Nafion{reg_sign} display in the esterification of n-butanol with acetic acid (TOF {approx} 1 min{sup -1} {at} 343 K). Water adsorbs strongly up to 4 molecules per sulfoxy acid group, and an additional 2 molecules are taken up at lower temperatures in the 1-D pore channels of S-MIL-53(Al). The high water content and Broensted acidity provide the structure S-MIL-53(Al) a high proton conductivity up to moderate temperatures.

  12. Sulfate-reducing bacteria mediate thionation of diphenylarsinic acid under anaerobic conditions.

    PubMed

    Guan, Ling; Shiiya, Ayaka; Hisatomi, Shihoko; Fujii, Kunihiko; Nonaka, Masanori; Harada, Naoki

    2015-02-01

    Diphenylarsinic acid (DPAA) is often found as a toxic intermediate metabolite of diphenylchloroarsine or diphenylcyanoarsine that were produced as chemical warfare agents and were buried in soil after the World Wars. In our previous study Guan et al. (J Hazard Mater 241-242:355-362, 2012), after application of sulfate and carbon sources, anaerobic transformation of DPAA in soil was enhanced with the production of diphenylthioarsinic acid (DPTAA) as a main metabolite. This study aimed to isolate and characterize anaerobic soil microorganisms responsible for the metabolism of DPAA. First, we obtained four microbial consortia capable of transforming DPAA to DPTAA at a high transformation rate of more than 80% after 4 weeks of incubation. Sequencing for the bacterial 16S rRNA gene clone libraries constructed from the consortia revealed that all the positive consortia contained Desulfotomaculum acetoxidans species. In contrast, the absence of dissimilatory sulfite reductase gene (dsrAB) which is unique to sulfate-reducing bacteria was confirmed in the negative consortia showing no DPAA reduction. Finally, strain DEA14 showing transformation of DPAA to DPTAA was isolated from one of the positive consortia. The isolate was assigned to D. acetoxidans based on the partial 16S rDNA sequence analysis. Thionation of DPAA was also carried out in a pure culture of a known sulfate-reducing bacterial strain, Desulfovibrio aerotolerans JCM 12613(T). These facts indicate that sulfate-reducing bacteria are microorganisms responsible for the transformation of DPAA to DPTAA under anaerobic conditions.

  13. Mineralogy and Organic Geochemistry of Acid Sulfate Environments from Valles Caldera, New Mexico: Habitability, Weathering and Biosignatures

    NASA Astrophysics Data System (ADS)

    Vogel, M. B.; Des Marais, D. J.; Jahnke, L. L.; Kubo, M.

    2009-12-01

    We report on the mineralogy, organic preservation potential and habitability of sulfate deposits in acid sulfate volcanic settings at Valles Caldera, New Mexico. Fumaroles and acidic springs are potential analogs for aqueous environments on Mars and may offer insights into habitability of sulfate deposits such as those at Meridiani Planum. Sulfates recently detected on Mars are posited to have formed from fluids derived from basaltic weathering and igneous volatile input, ultimately precipitating from acidic brines subjected to desiccation and freeze-thaw cycles (McClennan and Grotzinger, 2008). Key issues concerning martian sulfate deposits are their relationship to aqueous clay deposits, and whether or not specific sulfates deposits represent former habitable environments (see Soderblum and Bell, 2008; Tosca et al., 2008). Modern terrestrial volcanic fumaroles and hot springs precipitate various Ca-, Mg- and Fe- sulfates along with clays, and can help clarify whether certain acid sulfate mineral assemblages reflect habitable environments. Valles caldera is a resurgent caldera last active in the Pleistocene (1.4 - 1.0 Ma) that hosts several active fumaroles and over 40 geothermal exploration wells (see Goff, 2009). Fumaroles and associated mudpots and springs at Valles range from pH < 1 to 3, and affect argillic alteration upon rhylolitic tuffs and sedimentary deposits (Charles et al., 1986). We identified assemblages containing gypsum, quartz, Al-sulfates, elemental sulfur, clays and other minerals using XRD and SEM-EDS. Our previous research has shown that sulfates from different marine depositional environments display textural and morphological traits that are indicative of biological influence, or specific conditions in the depositional environments (Vogel et al., 2009). Gypsum crystals that develop in the presence of microbial biofilms in marine environments may have distorted crystal morphologies, biofilm - associated dissolution features, and accessory

  14. Hexuronic acid stereochemistry determination in chondroitin sulfate glycosaminoglycan oligosaccharides by electron detachment dissociation.

    PubMed

    Leach, Franklin E; Ly, Mellisa; Laremore, Tatiana N; Wolff, Jeremy J; Perlow, Jacob; Linhardt, Robert J; Amster, I Jonathan

    2012-09-01

    Electron detachment dissociation (EDD) has previously provided stereo-specific product ions that allow for the assignment of the acidic C-5stereochemistry in heparan sulfate glycosaminoglycans (GAGs), but application of the same methodology to an epimer pair in the chondroitin sulfate glycoform class does not provide the same result. A series of experiments have been conducted in which glycosaminoglycan precursor ions are independently activated by electron detachment dissociation (EDD), electron induced dissociation (EID), and negative electron transfer dissociation (NETD) to assign the stereochemistry in chondroitin sulfate (CS) epimers and investigate the mechanisms for product ion formation during EDD in CS glycoforms. This approach allows for the assignment of electronic excitation products formed by EID and detachment products to radical pathways in NETD, both of which occur simultaneously during EDD. The uronic acid stereochemistry in electron detachment spectra produces intensity differences when assigned glycosidic and cross-ring cleavages are compared. The variations in the intensities of the doubly deprotonated (0,2)X(3) and Y(3) ions have been shown to be indicative of CS-A/DS composition during the CID of binary mixtures. These ions can provide insight into the uronic acid composition of binary mixtures in EDD, but the relative abundances, although reproducible, are low compared with those in a CID spectrum acquired on an ion trap. The application of principal component analysis (PCA) presents a multivariate approach to determining the uronic acid stereochemistry spectra of these GAGs by taking advantage of the reproducible peak distributions produced by electron detachment.

  15. Electrical conductivity of acidic chloride solutions

    NASA Astrophysics Data System (ADS)

    Majima, Hiroshi; Peters, Ernest; Awakura, Yasuhiro; Park, Sung Kook; Aoki, Masami

    1988-02-01

    The electrical conductivities of aqueous solutions in the system HCl-MCln (where M = K, Na, Mg, Ni, or Cd) were measured at different temperatures. The equivalent electrical conductivity of H+ was calculated on the basis of simple assumptions for these solutions, and show an inverse relationship with water activity in these solutions. The results obtained by varying temperatures, solute ratios, and ionic strength on the electrical conductivity were found to be consistent with a proton jump mechanism for the H+ ion, where the activity of water is the most significant parameter affecting its equivalent conductance, and a viscous (Stokes’ law) drag mechanism (i.e., Walden’s rule is obeyed) for other ions found in acidic solutions.

  16. Practical method to make a discrete memristor based on the aqueous solution of copper sulfate

    NASA Astrophysics Data System (ADS)

    Merrikh-Bayat, Farshad; Parvizi, Meysam

    2016-06-01

    A new method to realize a discrete memristor is proposed. The device under study consists of a tube filled of aqueous saturated solution of copper sulfate which can be electrolyzed by using two asymmetric copper electrodes, one of which has a considerably smaller cross-sectional area than to the other one. It is shown both theoretically and experimentally that this device has exactly the properties of a memristor if it is designed such that the electrical field and the current density on the thinner electrode when it acts as anode are sufficiently large. Different aspects of the proposed discrete memristor, including pinched hysteresis loop, on-off resistance ratio and memory volatilization, are studied and experimental results are presented.

  17. Magnetic field effects on copper metal deposition from copper sulfate aqueous solution.

    PubMed

    Udagawa, Chikako; Maeda, Aya; Katsuki, Akio; Maki, Syou; Morimoto, Shotaro; Tanimoto, Yoshifumi

    2014-05-08

    Effects of a magnetic field (≤0.5 T) on electroless copper metal deposition from the reaction of a copper sulfate aqueous solution and a zinc thin plate were examined in this study. In a zero field, a smooth copper thin film grew steadily on the plate. In a 0.38 T field, a smooth copper thin film deposited on a zinc plate within about 1 min. Then, it peeled off repeatedly from the plate. The yield of consumed copper ions increased about 2.1 times compared with that in a zero field. Mechanism of this magnetic field effect was discussed in terms of Lorentz force- and magnetic force-induced convection and local volta cell formation.

  18. Acid-Sulfate-Weathering Activity in Shergottite Sites on Mars Recorded in Grim Glasses

    NASA Technical Reports Server (NTRS)

    Rao, M. N.; Nyquist, L. E.; Ross, K.; Sutton, S. R.; Schwandt, C. S.

    2011-01-01

    Based on mass spectrometric studies of sulfur species in Shergotty and EET79001, [1] and [2] showed that sulfates and sulfides occur in different proportions in shergottites. Sulfur speciation studies in gas-rich impact-melt (GRIM) glasses in EET79001 by the XANES method [3] showed that S K-XANES spectra in GRIM glasses from Lith A indicate that S is associated with Ca and Al presumably as sulfides/sulfates whereas the XANES spectra of amorphous sulfide globules in GRIM glasses from Lith B indicate that S is associated with Fe as FeS. In these amorphous iron sulfide globules, [4] found no Ni using FE-SEM and suggested that the globules resulting from immiscible sulfide melt may not be related to the igneous iron sulfides having approximately 1-3% Ni. Furthermore, in the amorphous iron sulfides from 507 GRIM glass, [5] determined delta(sup 34)S values ranging from +3.5%o to -3.1%o using Nano-SIMS. These values plot between the delta(sup 34)S value of +5.25%o determined in the sulfate fraction in Shergotty [6] at one extreme and the value of -1.7%o obtained for igneous sulfides in EET79001 and Shergotty [7] at the other. These results suggest that the amorphous Fe-S globules likely originated by shock reduction of secondary iron sulfate phases occurring in the regolith precursor materials during impact [7]. Sulfates in the regolith materials near the basaltic shergottite sites on Mars owe their origin to surficial acid-sulfate interactions. We examine the nature of these reactions by studying the composition of the end products in altered regolith materials. For the parent material composition, we use that of the host shergottite material in which the impact glasses are situated.

  19. Geology and geochemistry of Summitville, Colorado: an epithermal acid sulfate deposit in a volcanic dome

    USGS Publications Warehouse

    Gray, J.E.; Coolbaugh, M.F.

    1994-01-01

    Geologic studies during recent open-pit mining at Summitville, Colorado, have provided new information on an epithermal acid sulfate Au-Ag-Cu deposit formed in a volcanic dome. Geologic mapping, geochemical studies of whole-rock samples from blast holes, and geologic and geochemical traverse studies refine the details of the evolution of the Summitville deposit. Six distinct events followed emplacement of the quartz latite volcanic dome and define the development of the Summitville deposit: 1) an early stage of acid sulfate alteration, 2) subsequent Cu sulfide and gold mineralization, 3) widespread hydrothermal brecciation, 4) volumetrically minor, base metal sulfide-bearing barite veining, 5) volumetrically minor, kaolinite matrix brecciation, and finally, 6) supergene oxidation. -from Authors

  20. Detection of copiapite in the northern Mawrth Vallis region of Mars: Evidence of acid sulfate alteration

    NASA Astrophysics Data System (ADS)

    Farrand, William H.; Glotch, Timothy D.; Horgan, Briony

    2014-10-01

    The Mawrth Vallis region on Mars is associated with extensive layered deposits containing a stratigraphic sequence of Fe/Mg smectites overlain by Al phyllosilicates. Earlier studies have reported restricted exposures of the ferric sulfate mineral jarosite on top of the sequence. In this paper we have used CRISM data covering the northern portion of the Mawrth Vallis region to find a new jarosite exposure and multiple occurrences of the mixed valence Fe-sulfate mineral copiapite (Fe2+Fe3+4(SO4)6(OH)2·20(H2O)). HiRISE imagery indicate that the copiapite exposures lie on top of the Al phyllosilicates and thus post-date that unit either as a coating or as extensive veins. The presumed copiapite exposures are associated with high values of a “SINDX” parameter derived from CRISM data. Application of several spectral matching metrics over a spectral subsection indicated several candidates for the high SINDX phase including copiapite, ferricopiapite and metavoltine (another mixed valence Fe-sulfate mineral). Visible and near infrared CRISM spectra of the high SINDX areas are most consistent with the phase being copiapite. On Earth copiapite generally occurs as efflorescent coatings in acid mine drainage environments or in association with acid sulfate soils. The presence of jarosite and copiapite indicates the presence of acidic waters. Such acid waters could have contributed to the formation of the underlying Al phyllosilicate minerals. A possible mode of origin for these minerals in this region would involve a fluctuating ground water table and the weathering of Fe sulfide minerals.

  1. Mineral Alteration in Acid-sulfate Fumaroles on Earth and Mars

    NASA Astrophysics Data System (ADS)

    McCollom, T. M.; Hynek, B. M.; Rogers, K. L.

    2011-12-01

    Recent observations made at Mars by orbiting spacecraft and landers have documented the widespread occurrence of sulfate-rich rocks across the planet. Although the settings and origins of these rocks are likely to be variable, at least some appear to have originated from hydrothermal alteration of volcanic rocks. In order to place constraints on the chemical and mineralogical processes that might give rise to sulfate-rich rocks in hydrothermal settings on Mars, we are studying of acid-sulfate alteration of basalt in fumarolic environments using a combination of field work, experiments, and numerical modeling. Examination of acid-sulfate altered basaltic cinders from active fumaroles at Cerro Negro volcano in Nicaragua indicates that the initial stage of alteration results predominantly in the formation of amorphous silica, gypsum, and natroalunite/natrojarosite, with minor amounts of iron oxides/oxyhydroxides. Laboratory experimental alteration of basalt cinders by sulfuric acid at 145 °C generated a similar suite of minerals, with amorphous Si-rich gel, anhydrite, and Fe-bearing natroalunite as the primary products, along with minor amounts of Fe oxides/oxyhydroxides and magnesium sulfates. Crystalline silicates, including clay minerals, are not observed in either the field samples or experimental products. During the initial stage of alteration in both field and laboratory samples, igneous phenocrysts decompose rapidly while the glass remains intact. Over time, cations inlcuding Ca, Mg, Fe, Al, and Na are progressively leached from the glass in the field samples, while the glass largely maintains its original morphology despite being composed predominantly of SiO2. Evaluation of the laboratory and field results with numerical geochemical models indicates that formation of the observed alteration products requires that (a) igneous silicate phenocrysts (plagioclase, augite, olivine) react much faster than basaltic glass and (b) there are kinetic inhibitions to the

  2. Selective binding of C-6 OH sulfated hyaluronic acid to the angiogenic isoform of VEGF(165).

    PubMed

    Lim, Dong-Kwon; Wylie, Ryan G; Langer, Robert; Kohane, Daniel S

    2016-01-01

    Vascular endothelial growth factor 165 (VEGF165) is an important extracellular protein involved in pathological angiogenesis in diseases such as cancer, wet age-related macular degeneration (wet-AMD) and retinitis pigmentosa. VEGF165 exists in two different isoforms: the angiogenic VEGF165a, and the anti-angiogenic VEGF165b. In some angiogenic diseases the proportion of VEGF165b may be equal to or higher than that of VEGF165a. Therefore, developing therapeutics that inhibit VEGF165a and not VEGF165b may result in greater anti-angiogenic activity and therapeutic benefit. To this end, we report the selective binding properties of sulfated hyaluronic acid (s-HA). Selective biopolymers offer several advantages over antibodies or aptamers including cost effective and simple synthesis, and the ability to make nanoparticles or hydrogels for drug delivery applications or VEGF165a sequestration. Limiting sulfation to the C-6 hydroxyl (C-6 OH) in the N-acetyl-glucosamine repeat unit of hyaluronic acid (HA) resulted in a polymer with strong affinity for VEGF165a but not VEGF165b. Increased sulfation beyond the C-6 OH (i.e. greater than 1 sulfate group per HA repeat unit) resulted in s-HA polymers that bound both VEGF165a and VEGF165b. The C-6 OH sulfated HA (Mw 150 kDa) showed strong binding properties to VEGF165a with a fast association rate constant (Ka; 2.8 × 10(6) M(-1) s(-1)), slow dissociation rate constant (Kd; 2.8 × 10(-3) s(-1)) and strong equilibrium binding constant (KD; ∼1.0 nM)), which is comparable to the non-selective VEGF165 binding properties of the commercialized therapeutic anti-VEGF antibody (Avastin(®)). The C-6 OH sulfated HA also inhibited human umbilical vein endothelial cell (HUVEC) survival and proliferation and human dermal microvascular endothelial cell (HMVEC) tube formation. These results demonstrate that the semi-synthetic natural polymer, C-6 OH sulfated HA, may be a promising biomaterial for the treatment of angiogenesis

  3. The effects of acid deposition on sulfate reduction and methane production in peatlands

    NASA Technical Reports Server (NTRS)

    Murray, Georgia L.; Hines, Mark E.; Bayley, Suzanne E.

    1992-01-01

    Peatlands, as fens and bods, make up a large percentage of northern latitude terrestrial environments. They are organic rich and support an active community of anaerobic bacteria, such as methanogenic and sulfate-reducing bacteria. The end products of these microbial activities, methane and hydrogen sulfide, are important components in the global biogeochemical cycles of carbon and sulfur. Since these two bacterial groups compete for nutritional substrates, increases in sulfate deposition due to acid rain potentially can disrupt the balance between these processes leading to a decrease in methane production and emission. This is significant because methane is a potent greenhouse gas that effects the global heat balance. A section of Mire 239 in the Experimental Lakes Area, in Northwestern Ontario, was artificially acidified and rates of sulfate reduction and methane production were measured with depth. Preliminary results suggested that methane production was not affected immediately after acidification. However, concentrations of dissolved methane decreased and dissolved sulfide increased greatly after acidification and both took several days to recover. The exact mechanism for the decrease in methane was not determined. Analyses are under way which will be used to determine rates of sulfate reduction. These results will be available by Spring and will be discussed.

  4. Identification of Organic Sulfate Esters in d-Limonene Ozonolysis SOA Under Acidic Condition

    NASA Astrophysics Data System (ADS)

    Iinuma, Y.; Mueller, C.; Boege, O.; Herrmann, H.

    2006-12-01

    Secondary organic aerosol (SOA) components from gas phase ozonolysis of d-limonene were investigated in a series of indoor chamber experiments. The compounds smaller than 300 Da were quantified using capillary electrophoresis coupled to electrospray ionisation ion trap mass spectrometry (CE/ESI-ITMS). HPLC coupled to an ESI-TOFMS and an ESI-ITMS was used for structural study of dimmers and oligomers. Only 10% of the produced SOA could be attributed to low molecular weight carboxylic acids (Mw<300). The oxidation products which have molecular weights over 300 were detected regardless of the seed particle acidity but the concentrations of these compounds were much higher for acidic seed particle experiments. Strong signals of the compounds with mass to charge ratios (m/z) 281, 465 and 481 were detected when sulphuric acid was used in the seed particles. These compounds showed a strong fragment of m/z 97 in MS2 or MS3 spectra indicating the presence of sulfate in the structures. HPLC/ESI-TOFMS analysis suggests the elemental compositions of C10H17O7S-, C20H33O10S- and C20H33O11S- for m/z 281, 465 and 481, respectively. Based on MS^{n} and TOFMS results, they are most likely organic sulfate esters, possibly formed by a heterogeneous acid catalyzed reaction of a limonene oxidation product and sulfuric acid in the particle phase. The concentrations of the organic sulfate ester were as high as 3.7 μgm-3 for m/z 281.

  5. Sulfated Steroid–Amino Acid Conjugates from the Irish Marine Sponge Polymastia boletiformis

    PubMed Central

    Smyrniotopoulos, Vangelis; Rae, Margaret; Soldatou, Sylvia; Ding, Yuanqing; Wolff, Carsten W.; McCormack, Grace; Coleman, Christina M.; Ferreira, Daneel; Tasdemir, Deniz

    2015-01-01

    Antifungal bioactivity-guided fractionation of the organic extract of the sponge Polymastia boletiformis, collected from the west coast of Ireland, led to the isolation of two new sulfated steroid-amino acid conjugates (1 and 2). Extensive 1D and 2D NMR analyses in combination with quantum mechanical calculations of the electronic circular dichroism (ECD) spectra, optical rotation, and 13C chemical shifts were used to establish the chemical structures of 1 and 2. Both compounds exhibited moderate antifungal activity against Cladosporium cucumerinum, while compound 2 was also active against Candida albicans. Marine natural products containing steroidal and amino acid constituents are extremely rare in nature. PMID:25812034

  6. Acid-Tolerant Sulfate-Reducing Bacteria Play a Major Role in Iron Cycling in Acidic Iron Rich Sediments

    NASA Astrophysics Data System (ADS)

    Enright, K. A.; Moreau, J. W.

    2008-12-01

    Climate change drives drying and acidification of many rivers and lakes. Abundant sedimentary iron in these systems oxidizes chemically and biologically to form iron-ox(yhydrox)ide crusts and "hardpans". Given generally high sulfate concentrations, the mobilization and cycling of iron in these environments can be strongly influenced by bacterial sulfate reduction. Sulfate-reducing bacteria (SRB) induce reductive dissolution of oxidized iron phases by producing the reductant bisulfide as a metabolic product. These environmentally ubiquitous microbes also recycle much of the fixed carbon in sediment-hosted microbial mat communities. With prevalent drying, the buffering capacity for protons liberated from iron oxidation is exceeded, and the activity of sulfate-reducers is restricted to those species capable of tolerating low pH (and generally highly saline, i.e. sulfate-rich) conditions. These species will sustain the recycling of iron from more crystalline phases to more bioavailable species, as well as act as the only source of bisulfide for photosynthesizing microbial communities. The phylogeny and physiology of acid-tolerant SRB is therefore important to Fe, S and C cycling in iron-rich sedimentary environments, particularly those on a geochemical trajectory towards acidification. Previous studies have shown that these SRB species tend to be highly novel. We studied two distinct environments along a geochemical continuum towards acidification. In both settings, iron redox transformations exert a major, if not controlling, influence on reduction potential. An acidified, iron- rich tidal marsh receiving acid-mine drainage (San Francisco Bay, CA, USA) contained abundant textural evidence for reductive dissolution of Fe(III) in sediments with pH values varying from 2.4 - 3.8. From these sediments, full-length novel dsrAB gene sequences from acid-tolerant SRB were recovered, and sulfur isotope profiles reflected biological fractionation of sulfur under even the most

  7. Effects of nitrate and water on the oxygen isotopic analysis of barium sulfate precipitated from solution

    USGS Publications Warehouse

    Hannon, Janet E.; Bohlke, Johnkarl F.; Mroczkowski, Stanley J.

    2008-01-01

    BaSO4 precipitated from mixed salt solutions by common techniques for SO isotopic analysis may contain quantities of H2O and NOthat introduce errors in O isotope measurements. Experiments with synthetic solutions indicate that δ18O values of CO produced by decomposition of precipitated BaSO4 in a carbon reactor may be either too low or too high, depending on the relative concentrations of SO and NO and the δ18O values of the H2O, NO, and SO. Typical δ18O errors are of the order of 0.5 to 1‰ in many sample types, and can be larger in samples containing atmospheric NO, which can cause similar errors in δ17O and Δ17O. These errors can be reduced by (1) ion chromatographic separation of SO from NO, (2) increasing the salinity of the solutions before precipitating BaSO4 to minimize incorporation of H2O, (3) heating BaSO4 under vacuum to remove H2O, (4) preparing isotopic reference materials as aqueous samples to mimic the conditions of the samples, and (5) adjusting measured δ18O values based on amounts and isotopic compositions of coexisting H2O and NO. These procedures are demonstrated for SO isotopic reference materials, synthetic solutions with isotopically known reagents, atmospheric deposition from Shenandoah National Park, Virginia, USA, and sulfate salt deposits from the Atacama Desert, Chile, and Mojave Desert, California, USA. These results have implications for the calibration and use of O isotope data in studies of SOsources and reaction mechanisms.

  8. Suppression of rice methane emission by sulfate deposition in simulated acid rain

    NASA Astrophysics Data System (ADS)

    Gauci, Vincent; Dise, Nancy B.; Howell, Graham; Jenkins, Meaghan E.

    2008-09-01

    Sulfate in acid rain is known to suppress methane (CH4) emissions from natural freshwater wetlands. Here we examine the possibility that CH4 emissions from rice agriculture may be similarly affected by acid rain, a major and increasing pollution problem in Asia. Our findings suggest that acid rain rates of SO42- deposition may help to reduce CH4 emissions from rice agriculture. Emissions from rice plants treated with simulated acid rain at levels of SO42- consistent with the range of deposition in Asia were reduced by 24% during the grain filling and ripening stage of the rice season which accounts for 50% of the overall CH4 that is normally emitted in a rice season. A single application of SO42- at a comparable level reduced CH4 emission by 43%. We hypothesize that the reduction in CH4 emission may be due to a combination of effects. The first mechanism is that the low rates of SO42- may be sufficient to boost yields of rice and, in so doing, may cause a reduction in root exudates to the rhizosphere, a key substrate source for methanogenesis. Decreasing a major substrate source for methanogens is also likely to intensify competition with sulfate-reducing microorganisms for whom prior SO42- limitation had been lifted by the simulated acid rain S deposition.

  9. A Geochemical and Mineralogical Model for Formation of Layered Sulfate Deposits at Meridiani Planum by Hydrothermal Acid-sulfate Alteration of Pyroclastic Basalt

    NASA Astrophysics Data System (ADS)

    McCollom, T. M.; Hynek, B. M.

    2012-12-01

    The Mars Exploration Rover (MER) Opportunity has extensively characterized sulfate-rich, hematite-bearing bedrock exposed at Meridiani Planum, Mars. Based on various measurements, the mineral composition of the bedrocks has been interpreted to include: amorphous silica/glass/phyllosilicates, Mg-, Ca-, and Fe-bearing sulfates including jarosite, minor amounts of igneous phases including plagioclase, pyroxene, olivine, and magnetite, and hematite [1,2]. Chemically, the bedrocks closely resemble the composition of pristine martian basalt with addition of S and O, and minor variations of Mg and Cl with depth [3,4]. Based on these and other observations, the MER team has proposed that the bedrocks represent chemically altered siliciclastic sediments combined with sulfate salts formed by evaporation of sulfate-bearing fluids, modified by transport and multiple stages of infiltrating groundwater [3,5]. Several alternative scenarios have been proposed for the origin of the rocks including large impacts [6], evaporating glacial deposits [7], acid-fog alteration [8], and hydrothermal acid-sulfate alteration of basalt [4]. In order to further evaluate the potential contribution of hydrothermal proceeses to the deposits, we performed numerical geochemical models of acid-sulfate alteration of martian basalt based on constraints provided by recent laboratory experiments. Experimental studies of alteration of basalt conducted in our lab [9] indicate that the initial stages of acid-sulfate alteration of pyroclastic basalt are characterized by rapid decomposition of igneous crystalline phases including plagioclase, pyroxene, and olivine, while the glass (and igneous phases protected within the glass) remain unreactive. Elements released by dissolving minerals are precipitated primarily as amorphous silica and Ca-, Al-, Fe- and Mg-bearing sulfates, while precipitation of phyllosilicates and Fe-oxides/oxyhydroxides (FeOx) is kinetically inhibited. Based on these constraints, models

  10. Sulfate adsorption at the buried hematite/solution interface investigated using total internal reflection (TIR)-Raman spectroscopy.

    PubMed

    Jubb, Aaron M; Verreault, Dominique; Posner, Ralf; Criscenti, Louise J; Katz, Lynn E; Allen, Heather C

    2013-06-15

    Sulfate adsorption at buried mineral/solution interfaces is of great interest in geochemistry and atmospheric aerosol chemistry due to the sulfate anion's environmental ubiquity and the wide role of physical and chemical phenomena that it impacts. Here we present the first application of total internal reflection-Raman (TIR-Raman) spectroscopy, a surface sensitive spectroscopy, to probe sulfate ion behavior at the buried hematite/solution interface. Hematite is the most thermodynamically stable iron oxide polymorph and as such is widely found in nature. Our results demonstrate the feasibility of a TIR-Raman approach to study simple, inorganic anion adsorption at buried interfaces. Moreover, our data suggest that inner-sphere sulfate adsorption proceeds in a bidentate fashion at the hematite surface. These results help clarify long-standing questions as to whether sulfate forms inner-sphere adsorption complexes at hematite surfaces in a mono- or bidentate fashion based on attenuated total reflection-infrared (ATR-IR) observations. Our results are discussed with perspective to this debate and the applicability of TIR-Raman spectroscopy to address ambiguities of ion adsorption to mineral surfaces.

  11. Preparation of metal-resistant immobilized sulfate reducing bacteria beads for acid mine drainage treatment.

    PubMed

    Zhang, Mingliang; Wang, Haixia; Han, Xuemei

    2016-07-01

    Novel immobilized sulfate-reducing bacteria (SRB) beads were prepared for the treatment of synthetic acid mine drainage (AMD) containing high concentrations of Fe, Cu, Cd and Zn using up-flow anaerobic packed-bed bioreactor. The tolerance of immobilized SRB beads to heavy metals was significantly enhanced compared with that of suspended SRB. High removal efficiencies of sulfate (61-88%) and heavy metals (>99.9%) as well as slightly alkaline effluent pH (7.3-7.8) were achieved when the bioreactor was fed with acidic influent (pH 2.7) containing high concentrations of multiple metals (Fe 469 mg/L, Cu 88 mg/L, Cd 92 mg/L and Zn 128 mg/L), which showed that the bioreactor filled with immobilized SRB beads had tolerance to AMD containing high concentrations of heavy metals. Partially decomposed maize straw was a carbon source and stabilizing agent in the initial phase of bioreactor operation but later had to be supplemented by a soluble carbon source such as sodium lactate. The microbial community in the bioreactor was characterized by denaturing gradient gel electrophoresis (DGGE) and sequencing of partial 16S rDNA genes. Synergistic interaction between SRB (Desulfovibrio desulfuricans) and co-existing fermentative bacteria could be the key factor for the utilization of complex organic substrate (maize straw) as carbon and nutrients source for sulfate reduction.

  12. Treatment of acid rock drainage using a sulfate-reducing bioreactor with zero-valent iron.

    PubMed

    Ayala-Parra, Pedro; Sierra-Alvarez, Reyes; Field, James A

    2016-05-05

    This study assessed the bioremediation of acid rock drainage (ARD) in flow-through columns testing zero-valent iron (ZVI) for the first time as the sole exogenous electron donor to drive sulfate-reducing bacteria in permeable reactive barriers. Columns containing ZVI, limestone or a mixture of both materials were inoculated with an anaerobic mixed culture and fed a synthetic ARD containing sulfuric acid and heavy metals (initially copper, and later also cadmium and lead). ZVI significantly enhanced sulfate reduction and the heavy metals were extensively removed (>99.7%). Solid-phase analyses showed that heavy metals were precipitated with biogenic sulfide in the columns packed with ZVI. Excess sulfide was sequestered by iron, preventing the discharge of dissolved sulfide. In the absence of ZVI, heavy metals were also significantly removed (>99.8%) due to precipitation with hydroxide and carbonate ions released from the limestone. Vertical-profiles of heavy metals in the columns packing, at the end of the experiment, demonstrated that the ZVI columns still had excess capacity to remove heavy metals, while the capacity of the limestone control column was approaching saturation. The ZVI provided conditions that enhanced sulfate reduction and generated alkalinity. Collectively, the results demonstrate an innovative passive ARD remediation process using ZVI as sole electron-donor.

  13. Speciation in aqueous solutions of nitric acid.

    PubMed

    Hlushak, S; Simonin, J P; De Sio, S; Bernard, O; Ruas, A; Pochon, P; Jan, S; Moisy, P

    2013-02-28

    In this study, speciation in aqueous solutions of nitric acid at 25 °C was assessed in two independent ways. First, Raman experiments were carried out and interpreted in terms of free nitrate ions, ion pairs and neutral HNO(3) molecules. In parallel, a model was developed to account for the formation of these two kinds of pairs. It was based on an extension of the binding mean spherical approximation (BiMSA), or associative MSA (AMSA), in which the size and the charge of the ions in the chemical pair may differ from those of the free ions. A simultaneous fit of the osmotic coefficient and of the proportion of free ions (obtained from Raman spectroscopy experiments) led to an estimation of the speciation in nitric acid solutions. The result obtained using this procedure was compared with the estimation obtained from the Raman experiments.

  14. Acid Mine Drainage and Metal Sulfate Minerals in the Shasta Mining District, California

    NASA Astrophysics Data System (ADS)

    Livingston, J. D.; Murphy, W. M.; Miller, R. M.; Ayars, E. J.

    2005-12-01

    Metal sulfate minerals were collected at four surface water drainage sites during September and October of 2004 in the Shasta Mining District, southern Klamath Mountains, Shasta County, California and analyzed by X-ray fluorescence, atomic absorption spectroscopy, and X-ray diffraction to determine elements present, quantities of Fe, Cu, and Zn, and mineralogy. The Shasta Mining District produced major quantities of Cu, Zn, and pyrite (S) with minor amounts of Au, Ag, and Fe from massive sulfide bodies (Kinkel et al., 1956). Three study sites are located on Iron Mountain and one study site is at Bully Hill. Although mining occurred during a period of just over 100 years, it is estimated that acid mine drainage (AMD) will continue from Iron Mountain for over 3,200 years (Nordstrom and Alpers, 1998). AMD at the study sites produces blooms of metal sulfates during California's Mediterranean climate summer. The minerals readily dissolve in the "first flush" of seasonal rain creating runoff water of low pH with high amounts of dissolved metals (Bayless and Olyphant, 1993; Jambor et al., 2000). Data were examined for mineralogical changes in time and space and for zoning of minerals on a scale of centimeters. Sulfate mineral samples are complex with some samples composed of over a dozen different minerals. Site 1 is located on Spring Creek downstream from the Iron Mountain superfund remediation site, so levels of Fe, Cu, and Zn in the sulfates at this site are lower than at the other sites. Two site 1 samples from the same location taken a month apart show Ca, Fe, Cu, Sr, Y, and Sn, and the first sample also has detectable Br. The metal sulfates identified from the first visit are celestine, cesanite, chessexite, hectorfloresite, and ungemachite, and the mineralogy of the second visit is bilinite, epsomite, millosevichite, and anhydrite. The Fe bearing sulfate mineral during the first visit is ungemachite, but bilinite was the Fe bearing mineral at the time of the second

  15. Alkaline earth cation extraction from acid solution

    DOEpatents

    Dietz, Mark; Horwitz, E. Philip

    2003-01-01

    An extractant medium for extracting alkaline earth cations from an aqueous acidic sample solution is described as are a method and apparatus for using the same. The separation medium is free of diluent, free-flowing and particulate, and comprises a Crown ether that is a 4,4'(5')[C.sub.4 -C.sub.8 -alkylcyclohexano]18-Crown-6 dispersed on an inert substrate material.

  16. Infrared and laser Raman spectral studies of bis( DL-aspartic acid) sulfate

    NASA Astrophysics Data System (ADS)

    Mary, M. Briget; Ramakrishnan, V.

    2005-11-01

    The infrared and Raman spectra of bis( DL-aspartic acid) sulfate in the crystalline state are recorded at room temperature and the vibrational assignments of the observed wavenumbers are made. The presence of two carbonyl (C dbnd O) groups has been identified in the title complex and the two carbonyl groups are in different environment. The extensive intermolecular hydrogen bonding in the crystal has been identified by the shifting of bands due to the stretching and bending modes of the various functional groups. The sulfate group forms the anion. Its fundamentals continue to be degenerate except for the asymmetric bending mode and it suggests that the Td symmetry of SO 42- group has not been affected in the crystal.

  17. NONLINEARITIES IN THE SULFATE SECONDARY FINE PARTICULATE RESPONSE TO NOX EMISSIONS REDUCTIONS AS MODELED BY THE REGIONAL ACID DEPOSITION MODEL

    EPA Science Inventory

    Attention is increasingly being devoted to the health effects of fine particulates. In regions that have a large production of sulfate, sulfuric acid and nitric acid compete for the available ammonia to form aerosols. In addition, the available nitric acid is the result of ur...

  18. Wet oxidation of salicylic acid solutions.

    PubMed

    Collado, Sergio; Garrido, Laura; Laca, Adriana; Diaz, Mario

    2010-11-15

    Salicylic acid is a frequent pollutant in several industrial wastewaters. Uncatalyzed wet air oxidation, which is a promising technique for the treatment of phenolic effluents, has not been analyzed yet for the removal of salicylic acid. The effect of different conditions of pH (1.3-12.3), pressure (1.0-4.1 MPa), temperature (413-443 K), and initial concentrations (1.45-14.50 mM) on the wet oxidation of salicylate/salicylic acid solutions have here been investigated. The pH value of the reaction media was found to be a key parameter for the rate of the oxidation process with an optimum at pH 3.1, when the concentrations of salicylic acid and salicylate were similar. The oxidation reaction followed pseudofirst-order kinetics with respect to salicylic acid and 0.82 order with respect to dissolved oxygen. Additionally, the evolution of the color during the wet oxidation was analyzed and discussed in relation with the formation of intermediate compounds. Then, a reaction pathway for the noncatalytic wet oxidation of the salicylic acid was proposed.

  19. Microbial sulfate reduction and metal attenuation in pH 4 acid mine water

    USGS Publications Warehouse

    Church, C.D.; Wilkin, R.T.; Alpers, C.N.; Rye, R.O.; Blaine, R.B.

    2007-01-01

    Sediments recovered from the flooded mine workings of the Penn Mine, a Cu-Zn mine abandoned since the early 1960s, were cultured for anaerobic bacteria over a range of pH (4.0 to 7.5). The molecular biology of sediments and cultures was studied to determine whether sulfate-reducing bacteria (SRB) were active in moderately acidic conditions present in the underground mine workings. Here we document multiple, independent analyses and show evidence that sulfate reduction and associated metal attenuation are occurring in the pH-4 mine environment. Water-chemistry analyses of the mine water reveal: (1) preferential complexation and precipitation by H2S of Cu and Cd, relative to Zn; (2) stable isotope ratios of 34S/32S and 18O/16O in dissolved SO4 that are 2-3 ??? heavier in the mine water, relative to those in surface waters; (3) reduction/oxidation conditions and dissolved gas concentrations consistent with conditions to support anaerobic processes such as sulfate reduction. Scanning electron microscope (SEM) analyses of sediment show 1.5-micrometer, spherical ZnS precipitates. Phospholipid fatty acid (PLFA) and denaturing gradient gel electrophoresis (DGGE) analyses of Penn Mine sediment show a high biomass level with a moderately diverse community structure composed primarily of iron- and sulfate-reducing bacteria. Cultures of sediment from the mine produced dissolved sulfide at pH values near 7 and near 4, forming precipitates of either iron sulfide or elemental sulfur. DGGE coupled with sequence and phylogenetic analysis of 16S rDNA gene segments showed populations of Desulfosporosinus and Desulfitobacterium in Penn Mine sediment and laboratory cultures. ?? 2007 Church et al; licensee BioMed Central Ltd.

  20. A spectrophotometric study of neodymium(III) complexation in sulfate solutions at elevated temperatures

    NASA Astrophysics Data System (ADS)

    Migdisov, Art. A.; Reukov, V. V.; Williams-Jones, A. E.

    2006-02-01

    The formation constants of neodymium complexes in sulfate solutions have been determined spectrophotometrically at temperatures of 30-250 °C and a pressure of 100 bars. The dominant species in the solution are NdSO 4+ and Nd(SO 4) 2-, with the latter complex being more important at higher temperature. Equilibrium constants were calculated for the following reactions: Nd+SO4=NdSO4,β1; Nd+2·SO4=Nd(SO4)2,β2; NdSO4+SO4=Nd(SO4)2,Ks. The values of β1 and β2, were determined for 30 and 100 °C, whereas for higher temperatures it was only possible to determine the stepwise formation constant Ks. The values of the formation constants obtained in this study for 30 and 100 °C are in excellent agreement with those predicted theoretically by Wood [Wood, S.A., 1990b. The aqueous geochemistry of the rare-earth elements and yttrium. 2. Theoretical predictions of speciation in hydrothermal solutions to 350 °C at saturation water vapor pressure. Chem. Geol.88 (1-2), 99-125] and Haas et al. [Haas, J.R., Shock, E.L., Sassani, D.C., 1995. Rare earth elements in hydrothermal sysytems: estimates of standard partial molal thermodynamic properties of aqueous complexes of the rare earth elements at high pressures and temperatures. Geochim. Cosmochim. Acta59 (21), 4329-4350], and those for the stepwise formation constant ( Ks) agree reasonably well with the predictions of Wood (1990b).

  1. A simple method for isolating chicken egg yolk immunoglobulin using effective delipidation solution and ammonium sulfate.

    PubMed

    Tong, Chenyao; Geng, Fang; He, Zhenjiao; Cai, Zhaoxia; Ma, Meihu

    2015-01-01

    Chicken egg yolk immunoglobulin (IgY) is a superior alternative to mammalian immunoglobulin. However, the practical application of IgY in research, diagnostics, and functional food is limited due to complex or time-consuming purification procedures. The objective of this study was to develop a simple, safe, large-scale separation method for IgY from egg yolk. Egg yolk was diluted with 6-fold delipidation solutions made of different types (pectin, λ-carrageenan, carboxymethylcellulose, methylcellulose, and dextran sulfate) and concentrations (0.01, 0.05, 0.1, 0.15, and 0.2%) of polysaccharides, respectively. The yolk solution was adjusted to pH 5.0, and then kept overnight at 4°C before being centrifuged at 4°C. The resulting supernatant was added to 35% (w/v) (NH4)2SO4 and then centrifuged. The precipitant, which contained IgY, was dissolved in distilled water and then dialyzed. SDS-PAGE and Western blotting were utilized to conduct qualitative analysis of IgY; high-performance liquid chromatography (HPLC) was used for quantitative analysis. The immunoreactivity of IgY was measured by ELISA. The results showed that yield, purity, and immunoreactivity varied with types and concentrations of polysaccharides. The optimal isolation of IgY for pectin, λ-carrageenan, dextran sulfate, and carboxymethylcellulose was at the concentration of 0.1%; for methylcellulose, optimal isolation was at 0.15%. The best results were obtained in the presence of 0.1% pectin. In this condition, yield and purity can reach 8.36 mg/mL egg yolk and 83.3%, respectively, and the negative effect of IgY on immunoreactivity can be minimized. The procedure of isolation was simplified to 2 steps with a higher yield of IgY, avoiding energy- and time-consuming methods. Therefore, the isolation condition under study has a great potential for food industry production of IgY on a large scale.

  2. Silver-silver sulfate reference electrodes for use in lead-acid batteries

    NASA Astrophysics Data System (ADS)

    Ruetschi, Paul

    Electrochemical properties of silver-silver sulfate reference electrodes for lead-acid batteries are described, and the following possible applications discussed: Determination of individual capacities of positive and negative plates. Monitoring individual electrode behavior during deep discharge and cell reversal. Optimization charge or discharge parameters, by controlling the current such that pre-determined limits of positive or negative half-cell potential are respected. Observation of acid concentration differences, for example due to acid stratification, by measuring diffusion potentials (concentration-cell voltages). Detection of defective cells, and defective plate sets, in a string of cells, at the end of their service life. Silver-silver sulfate reference electrodes, permanently installed in lead-acid cells, may be a means to improve battery management, and therewith to improve reliability and service life. In vented batteries, reference electrodes may be used to limit positive plate polarization during charge, or float-charge. Limiting the positive half-cell potential to an upper, pre-set value would permit to keep anodic corrosion as low as possible. During cycling, discharge could be terminated when the half-cell potential of the positive electrode has dropped to a pre-set limit. This would prevent excessive discharge of the positive electrodes, which could result in an improvement of cycle life. In valve-regulated batteries, reference electrodes may be used to adjust float-charge conditions such as to assure sufficient cathodic polarization of the negative electrodes, in order to avoid sulfation. The use of such reference electrodes could be beneficial particularly in multi-cell batteries, with overall voltages above 12 V, operated in a partial-state-of-charge.

  3. Cerro Negro, Nicaragua: A key Mars Analog Environment for Acid-Sulfate Weathering

    NASA Astrophysics Data System (ADS)

    Hynek, B. M.; Rogers, K. L.; McCollom, T. M.

    2008-12-01

    Sulfate-rich bedrock has been discovered in many locations on Mars and has been studied by both orbiting spacecraft and landers. It appears that in most cases these minerals are produced by acid-sulfate weathering of igneous rocks, which may have been a widespread process for the first billion years of Mars' history. The origin of life on Earth may have occurred in iron-sulfur hydrothermal settings and it is conceivable that early Mars had similar environmental conditions. An excellent terrestrial analog for acid- sulfate weathering of Mars-like basalts exists at Cerro Negro (CN), Nicaragua, where sulfur-bearing gases interact with recently erupted basaltic ash in numerous fumaroles. To date, we have made two expeditions to CN to assess the chemical, mineralogical, and biological conditions. At the fumaroles pH ranges from <1 to 5 and temperatures range from 40 to 400° C. Basalts with a chemical composition very similar to those on Mars are being chemically altered in the solfatara setting. In a few years, freshly erupted basalt can be converted into predominately Ca-, Mg-, and Fe-sulfates, Fe-hydroxides (including jarosite), clays, and free silica. Altered rocks have up to 30 wt% SO3 equivalent, which is similar to the Meridiani Planum bedrocks and inferred in other sulfate-bearing bedrock on Mars. Moreover, heavily weathered rocks have silica contents up to 80 wt%, similar to silica-rich soils at Gusev Crater that possibly formed in hydrothermal environments. Samples were collected for biological analysis including enrichment and isolation of novel thermophiles as well as molecular characterization of thermophile diversity. The low water and nutrient levels found in solfatara environments lead to less biomass when compared to hot springs with similar geochemical conditions. Nonetheless, microbes are thriving in these hot, acidic vent environments. At Cerro Negro solfatara, we are characterizing the metabolic and phylogenetic diversity of resident microbial

  4. Role of vanadium(V) in the aging of the organic phase in the extraction of uranium(VI) by Alamine 336 from acidic sulfate leach liquors

    SciTech Connect

    Chagnes, A.; Cote, G.; Courtaud, B.; Thiry, J.

    2008-07-01

    The present work is focussed on the chemical degradation of Alamine 336-tridecanol-n-dodecane solvent which used in the recovery of uranium by solvent extraction. Degradation occurs due to the presence of vanadium(V), an oxidant, in the feed solution. After a brief overview of the chemistry of vanadium, the kinetics of degradation of the solvent when contacted with acidic sulfate leach liquor was investigated and interpreted by the Michelis-Menten mechanism. GCMS analyses evidenced the presence of tridecanoic acid and dioctylamine as degradation products. A mechanism of degradation is discussed. (authors)

  5. Acidities of Water and Methanol in Aqueous Solution and DMSO

    ERIC Educational Resources Information Center

    Gao, Daqing

    2009-01-01

    The relative acidities of water and methanol have been a nagging issue. In gas phase, methanol is more acidic than water by 36.0 kJ/mol; however, in aqueous solution, the acidities of methanol and water are almost identical. The acidity of an acid in solution is determined by both the intrinsic gas-phase ionization Gibbs energy and the solvent…

  6. Desulfotomaculum alcoholivorax sp. nov., a moderately thermophilic, spore-forming, sulfate-reducer isolated from a fluidized-bed reactor treating acidic metal- and sulfate-containing wastewater.

    PubMed

    Kaksonen, Anna H; Spring, Stefan; Schumann, Peter; Kroppenstedt, Reiner M; Puhakka, Jaakko A

    2008-04-01

    A moderately thermophilic, Gram-positive, endospore-forming, sulfate-reducing bacterium was isolated from a fluidized-bed reactor treating acidic water containing metal and sulfate. The strain, designated RE35E1T, was rod-shaped and motile. The temperature range for growth was 33-51 degrees C (optimum 44-46 degrees C) and the pH range was 6.0-7.5 (optimum pH 6.4-7.3). The strain grew optimally without additional NaCl. The electron acceptors were 10 mM sulfate, thiosulfate and elemental sulfur and 1 mM (but not 10 mM) sulfite. Various alcohols and carboxylic acids were utilized as electron donors. Fermentative growth occurred on pyruvate. The cell wall contained meso-diaminopimelic acid, and the major respiratory isoprenoid quinone was menaquinone MK-7. The major whole-cell fatty acids were iso-C15 : 0, iso-C17 : 1 omega 10c and iso-C17 : 0. Strain RE35E1T was related to representatives of the genera Desulfotomaculum and Sporotomaculum, the closest relatives being Desulfotomaculum arcticum DSM 17038T (96.3 % 16S rRNA gene sequence similarity) and Sporotomaculum hydroxybenzoicum DSM 5475T (92.0 % similarity). Strain RE35E1T represents a novel species, for which the name Desulfotomaculum alcoholivorax sp. nov. is proposed. The type strain is RE35E1T (=DSM 16058T=JCM 14019T).

  7. FY-15 Progress Report on Cleanup of irradiated SHINE Target Solutions Containing 140g-U/L Uranyl Sulfate

    SciTech Connect

    Bennett, Megan E.; Bowers, Delbert L.; Vandegrift, George F.

    2015-09-01

    During FY 2012 and 2013, a process was developed to convert the SHINE Target Solution (STS) of irradiated uranyl sulfate (140 g U/L) to uranyl nitrate. This process is necessary so that the uranium solution can be processed by the UREX (Uranium Extraction) separation process, which will remove impurities from the uranium so that it can be recycled. The uranyl sulfate solution must contain <0.02 M SO42- so that the uranium will be extractable into the UREXsolvent. In addition, it is desired that the barium content be below 0.0007 M, as this is the limit in the Resource Conservation and Recovery Act (RCRA).

  8. Thermodynamic data for modeling acid mine drainage problems: compilation and estimation of data for selected soluble iron-sulfate minerals

    USGS Publications Warehouse

    Hemingway, Bruch S.; Seal, Robert R., II; Chou, I-Ming

    2002-01-01

    Enthalpy of formation, Gibbs energy of formation, and entropy values have been compiled from the literature for the hydrated ferrous sulfate minerals melanterite, rozenite, and szomolnokite, and a variety of other hydrated sulfate compounds. On the basis of this compilation, it appears that there is no evidence for an excess enthalpy of mixing for sulfate-H2O systems, except for the first H2O molecule of crystallization. The enthalpy and Gibbs energy of formation of each H2O molecule of crystallization, except the first, in the iron(II) sulfate - H2O system is -295.15 and -238.0 kJ?mol-1, respectively. The absence of an excess enthalpy of mixing is used as the basis for estimating thermodynamic values for a variety of ferrous, ferric, and mixed-valence sulfate salts of relevance to acid-mine drainage systems.

  9. Separation of copper from aqueous sulfate solutions by mixtures of Cyanex 301 and LIX 984N.

    PubMed

    Fouad, E A

    2009-07-30

    The extraction equilibria of copper(II) with Cyanex 301, LIX 984N, and their mixtures have been investigated. Extraction was studied as a function of organic phase composition, sulfuric acid concentration, pH, temperature, initial copper concentration, mixing speed, and aqueous/organic volume ratio. Considerable synergistic enhancement has been observed in the extraction of Cu(2+) with mixtures of Cyanex 301 and LIX 984N. The results demonstrate that copper ion is extracted as CuRL(2)H with synergistic mixture. The thermodynamic parameter, enthalpy change (Delta H) of Cyanex 301, LIX 984N, and their mixtures have been determined and the endothermic process has been found. The synergistic enhancement factor of copper(II) with mixtures is higher at more acidic solutions, which suggests that it is a promising synergistic extraction system for the separation of copper(II) from more acidic medium. HCl was found to be more efficient for copper stripping from loaded synergistic mixtures.

  10. Modeling and experimental validation of electroplating deposit distributions in copper sulfate solutions

    NASA Astrophysics Data System (ADS)

    Robison, Mark Robert

    Uniform deposits are typically desired in electrodeposition; however, the geometry of the deposited surface often makes a uniform deposit difficult to achieve. The objectives of this thesis are to provide experimental and modeling data for deposit uniformity of several geometries in a copper sulfate solution and to create a model capable of predicting deposit uniformity on any geometry. Bench scale electroplating cells were set up to test deposit distributions of multiple geometries as well as to test deposit uniformity with varying copper concentrations and temperatures ranging from 30 g/L to 50 g/L Cu2+ and 30 °C to 60 °C. The deposit uniformity was determined by cross-sectioning the samples. Models were generated using a finite element analysis-based software package named COMSOL Multiphysics. The model results were compared to experimental results to verify model accuracy. Model results were determined to be accurate as long as the cathode size was not too small. In addition, a numerical model was developed based on cell geometry, current density, and limiting current density. This numerical model was compared with the COMSOL model, and the results show very good agreement between the two models. Results from the electrodeposition experiments, COMSOL model, and numerical model can be used to predict copper electrodeposition profiles and uniformity in a wide range of conditions and geometries.

  11. Uremic retention solute indoxyl sulfate level is associated with prolonged QTc interval in early CKD patients.

    PubMed

    Tang, Wei-Hua; Wang, Chao-Ping; Chung, Fu-Mei; Huang, Lynn L H; Yu, Teng-Hung; Hung, Wei-Chin; Lu, Li-Fen; Chen, Po-Yuan; Luo, Ching-Hsing; Lee, Kun-Tai; Lee, Yau-Jiunn; Lai, Wen-Ter

    2015-01-01

    Total mortality and sudden cardiac death is highly prevalent in patients with chronic kidney disease (CKD). In CKD patients, the protein-bound uremic retention solute indoxyl sulfate (IS) is independently associated with cardiovascular disease. However, the underlying mechanisms of this association have yet to be elucidated. The relationship between IS and cardiac electrocardiographic parameters was investigated in a prospective observational study among early CKD patients. IS arrhythmogenic effect was evaluated by in vitro cardiomyocyte electrophysiological study and mathematical computer simulation. In a cohort of 100 early CKD patients, patients with corrected QT (QTc) prolongation had higher IS levels. Furthermore, serum IS level was independently associated with prolonged QTc interval. In vitro, the delay rectifier potassium current (IK) was found to be significantly decreased after the treatment of IS in a dose-dependent manner. The modulation of IS to the IK was through the regulation of the major potassium ion channel protein Kv 2.1 phosphorylation. In a computer simulation, the decrease of IK by IS could prolong the action potential duration (APD) and induce early afterdepolarization, which is known to be a trigger mechanism of lethal ventricular arrhythmias. In conclusion, serum IS level is independently associated with the prolonged QTc interval in early CKD patients. IS down-regulated IK channel protein phosphorylation and the IK current activity that in turn increased the cardiomyocyte APD and QTc interval in vitro and in the computer ORd model. These findings suggest that IS may play a role in the development of arrhythmogenesis in CKD patients.

  12. Capture chromatography for Mo-99 recovery from uranyl sulfate solutions: minimum-column-volume design method.

    PubMed

    Ling, Lei; Chung, Pei-Lun; Youker, Amanda; Stepinski, Dominique C; Vandegrift, George F; Wang, Nien-Hwa Linda

    2013-09-27

    Molybdenum-99 (Mo-99), generated from the fission of Uranium-235 (U-235), is the radioactive parent of the most widely used medical isotope, technetium-99m (Tc-99m). An efficient, robust, low-pressure process is developed for recovering Mo-99 from uranyl sulfate solutions. The minimum column volume and the maximum column length for required yield, pressure limit, and loading time are determined using a new graphical method. The method is based on dimensionless groups and intrinsic adsorption and diffusion parameters, which are estimated using a small number of experiments and simulations. The design is tested with bench-scale experiments with titania columns. The results show a high capture yield and a high stripping yield (95±5%). The design can be adapted to changes in design constraints or the variations in feed concentration, feed volume, or material properties. The graph shows clearly how the column utilization is affected by the required yield, loading time, and pressure limit. The cost effectiveness of various sorbent candidates can be evaluated based on the intrinsic parameters. This method can be used more generally for designing other capture chromatography processes.

  13. Synthesis of a sulfonic acid mimetic of the sulfated Lewis A pentasaccharide.

    PubMed

    Jakab, Zsolt; Fekete, Anikó; Csávás, Magdolna; Borbás, Anikó; Lipták, András; Antus, Sándor

    2012-03-01

    The first sulfonic acid mimetic of the sulfated Lewis A pentasaccharide in which the natural L-fucose unit is replaced by a D-arabinose ring was synthesized. Formation of the sulfonic acid moiety at a pentasaccharide level could be successfully achieved by means of introduction of an acetylthio moiety into the terminal D-galactose residue and subsequent oxidation. The equatorial arrangement of the acetylthio group linked to C-3 of the galactose ring could be obtained by double nucleophilic substitutions; efficient formation of the gulo-triflate derivatives required low-power microwave (MW) activation. Oxidation of the acetylthio group was carried out using Oxone in the presence of acetic acid.

  14. Supported zirconium sulfate on carbon nanotubes as water-tolerant solid acid catalyst

    SciTech Connect

    Juan, Joon Ching; Jiang Yajie; Meng Xiujuan; Cao Weiliang; Yarmo, Mohd Ambar; Zhang Jingchang . E-mail: zhangjc1@mail.buct.edu.cn

    2007-07-03

    A new solid acid of zirconium sulfate (CZ) was successfully supported on carbon nanotube (CNT) for esterification reaction. Preparation conditions of the supported CZ have been investigated, to obtain highest catalytic activity for esterification reaction. XRD, TEM, BET, X-ray photoelectron spectra (XPS) and in situ FTIR analysis has also been carried out to understand the characteristics of the catalyst. In the esterification of acrylic acid with n-octanol, the supported CZ exhibited high catalytic activity and stability. The catalytic activity was nearly unchanged during four times of reuse. XRD and TEM analysis indicated that CZ was finely dispersed on CNT. XPS analysis shows that the CZ species was preserved and the chemical environment of the CZ has changed after loaded on CNT. This finding show that CNT as CZ support is an efficient water-tolerant solid acid.

  15. Sulfated glycosaminoglycans and glucosamine may synergize in promoting synovial hyaluronic acid synthesis.

    PubMed

    McCarty, M F; Russell, A L; Seed, M P

    2000-05-01

    High-molecular-weight hyaluronic acid (HA) produced by the synovium may function physiologically to aid preservation of cartilage structure and prevent arthritic pain; both the size and concentration of HA in synovial fluid are diminished in osteoarthritis (OA). Glucosamine therapy for OA can be expected to increase synovial HA production by providing rate-limiting substrate. In addition, certain sulfated glycosaminoglycans and polysaccharides - including chondroitin sulfate (CS), dermatan sulfate, and pentosan polysulfate - stimulate synovial HA production, apparently owing to a hormone-like effect triggered by the binding of these polymers to membrane proteins of synovial cells. Surprisingly, a significant proportion of orally administered CS is absorbed as intact polymers - apparently by pinocytosis. These considerations may rationalize clinical studies concluding that oral CS provides slow-onset but durable pain relief and functional improvement in OA. The possibility that oral glucosamine and CS may interact in a complementary or synergistic fashion to improve synovial fluid HA content in OA should be assessed in clinical studies, and the potential of adjunctive CS administration to improve the clinical response achievable with optimal intakes of glucosamine should likewise be evaluated. In light of the fact that the synovium virtually functions as a 'placenta' for cartilage, focusing on synovium as the target for therapeutic intervention in OA may be a rational strategy.

  16. Groundwater or floodwater? Assessing the pathways of metal exports from a coastal acid sulfate soil catchment.

    PubMed

    Santos, Isaac R; de Weys, Jason; Eyre, Bradley D

    2011-11-15

    Daily observations of dissolved aluminum, iron, and manganese in an estuary downstream of a coastal acid sulfate soil (CASS) catchment provided insights into how floods and submarine groundwater discharge drive wetland metal exports. Extremely high Al, Fe, and Mn concentrations (up to 40, 374, and 8 mg L(-1), respectively) were found in shallow acidic groundwaters from the Tuckean Swamp, Australia. Significant correlations between radon (a natural groundwater tracer) and metals in surface waters revealed that metal loads were driven primarily by groundwater discharge. Dissolved Fe, Mn, and Al loads during a 16-day flood triggered by a 213 mm rain event were respectively 80, 35, and 14% of the total surface water exports during the four months of observations. Counter clockwise hysteresis was observed for Fe and Mn in surface waters during the flood due to delayed groundwater inputs. Groundwater-derived Fe fluxes into artificial drains were 1 order of magnitude higher than total surface water exports, which is consistent with the known accumulation of monosulfidic black ooze within the wetland drains. Upscaling the Tuckean catchment export estimates yielded dissolved Fe fluxes from global acid sulfate soil catchments on the same order of magnitude of global river inputs into estuaries.

  17. Ascorbic acid protects against colistin sulfate-induced neurotoxicity in PC12 cells.

    PubMed

    Liu, Yang; Dai, Chongshan; Gao, Ruixia; Li, Jichang

    2013-10-01

    This study aimed to examine the protective effect of ascorbic acid against colistin-induced neurotoxicity mediated by oxidative stress, a potential mechanism. An in vitro neurotoxicity model was established with PC12 cells exposed to 125 µg/mL colistin sulfate for 24 h. PC12 cells were treated with colistin (125 µg/mL) in the absence and presence of ascorbic acid (0.1, 1.0 and 10 µM/mL) for 24 h. Both 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) assay and lactate dehydrogenase (LDH) assay were carried out to evaluate cell viability. The levels of intracellular reactive oxygen species (ROS), superoxide dismutase (SOD) and glutathione (GSH) levels were assessed. Moreover, we tested the level of DNA fragmentation, the release of cytochrome-c and the expressions of caspase-9 and -3 mRNA. The results showed that 1 and 10 µM/mL ascorbic acid significantly increased the cell viability and the levels of SOD and GSH (both p<0.05), while 0.1, 1 and 10 µM/mL ascorbic acid significantly decreased the generation of ROS, the release of cytochrome-c, formation of DNA fragmentation and the expressions of caspase-9 and -3 mRNA in colistin-treated PC12 cells, compared with the colistin model group. These results suggest that ascorbic acid could reduce colistin sulfate-induced neurotoxicity through the resistance of oxidative stress and the prevention of apoptosis mediated via mitochondria pathway. They also highlight the potential of coadministering ascorbic acid to widen the therapeutic dose of colistin.

  18. Aerosol pH buffering in the southeastern US: Fine particles remain highly acidic despite large reductions in sulfate

    NASA Astrophysics Data System (ADS)

    Weber, R. J.; Guo, H.; Russell, A. G.; Nenes, A.

    2015-12-01

    pH is a critical aerosol property that impacts many atmospheric processes, including biogenic secondary organic aerosol formation, gas-particle phase partitioning, and mineral dust or redox metal mobilization. Particle pH has also been linked to adverse health effects. Using a comprehensive data set from the Southern Oxidant and Aerosol Study (SOAS) as the basis for thermodynamic modeling, we have shown that particles are currently highly acidic in the southeastern US, with pH between 0 and 2. Sulfate and ammonium are the main acid-base components that determine particle pH in this region, however they have different sources and their concentrations are changing. Over 15 years of network data show that sulfur dioxide emission reductions have resulted in a roughly 70 percent decrease in sulfate, whereas ammonia emissions, mainly link to agricultural activities, have been largely steady, as have gas phase ammonia concentrations. This has led to the view that particles are becoming more neutralized. However, sensitivity analysis, based on thermodynamic modeling, to changing sulfate concentrations indicates that particles have remained highly acidic over the past decade, despite the large reductions in sulfate. Furthermore, anticipated continued reductions of sulfate and relatively constant ammonia emissions into the future will not significantly change particle pH until sulfate drops to clean continental background levels. The result reshapes our expectation of future particle pH and implies that atmospheric processes and adverse health effects linked to particle acidity will remain unchanged for some time into the future.

  19. The action of flufenamic acid and other nonsteroidal anti-inflammatories on sulfate transport in the isolated perfused rat liver.

    PubMed

    Lopez, C H; Bracht, A; Yamamoto, N S; Ishii-Iwamoto, E L; Sampaio, E; Kelmer-Bracht, A M

    1999-06-01

    The influence of flufenamic acid and other nonsteroidal anti-inflammatories on sulfate transport in the liver was investigated. The experimental system was the isolated perfused rat liver. Perfusion was accomplished in an open, nonrecirculating system. The perfusion fluid was Krebs/Henseleit-bicarbonate buffer (pH 7.4), saturated with a mixture of oxygen and carbon dioxide (95:5) by means of a membrane oxygenator and heated to 37 degrees C. Sulfate transport (equilibrium exchange) was measured by employing the multiple-indicator dilution technique with simultaneous injection (impulse input) of [35S]sulfate. [3H]sucrose (indicator for the distribution of the sinusoidal transit times), and [3H]water (indicator for the total aqueous space). Analysis was accomplished by means of a space-distributed variable transit time model. Flufenamic acid and other anti-inflammatories inhibited sulfate transport in the liver. For a concentration of 100 microM, the following decreasing series of potency could be established: flufenamic acid (53.4 +/- 2.9%) > niflumic acid (41.1 +/- 1.4%) > mefenamic acid (35.6 +/- 3.3%) > piroxicam (16.6 +/- 1.9%) > naproxen (13.5 +/- 8.4)%) nimesulide (11.6 +/- 5.8%). Inhibition of sulfate transport by flufenamic acid was clearly concentration dependent; 250 microM flufenamic acid produced more than 95% inhibition. Flufenamic acid in the range between 50 and 250 microM did not affect the mean transit times of tritiated water (t water) and [3H]sucrose (t suc), the same applying to all other anti-inflammatory agents (100 microM) tested in this work. This means that these agents do not affect vascular and cellular spaces, even when present at high concentrations. The ratio of the intra- to extracellular sulfate concentrations ([C]i/[C]e), generally between 0.4 and 0.5 under control conditions, was affected only by 250 microM flufenamic acid and 100 microM niflumic acid. In the first case, this phenomenon is possibly due to the high degree of transport

  20. Comparison between the efficacy of 10% zinc sulfate solution with 4% hydroquinone cream on improvement of melasma

    PubMed Central

    Iraji, Fariba; Tagmirriahi, Nabet; Gavidnia, Keyvan

    2012-01-01

    Background: Melasma, a common disorder of hyperpigmentation, is often difficult to treat. Although 10% zinc sulfate solution has been reported to be useful for patients with melasma, controlled trials are lacking. Materials and Methods: 72 women with moderate to severe melasma were divided randomly into 2 groups. Group A were treated with 10% zinc sulfate solution and group B with 4% hydroquinone cream twice-daily. The results were evaluated by photoevaluation by patients based on subjective satisfaction and a blinded dermatologist using MASI score. Assessments were obtained at baseline and at 2 and 6 months after starting treatment. Results: According to MASI score changes during treatment, there was a reduction in both groups at 2 months, however, the reduction in group B was more significant (the reduction in mean ± SD MASI was 0.7 ± 0.7 in group A vs. 2.7 ± 1.6 in group B). In addition, the patients in group B continued to decrease MASI score for the remainder of the study period at 6 months follow-up (0.3 ± 0.5) in comparison with patients in group A who did not show more reduction in MASI score. Conclusions: The study indicates that topical zinc sulfate is not as effective in treating disease as was observed in the previous open study. A comparative study with sunscreen and placebo is necessary to determine if topical zinc sulfate is truly superior to sunscreen and placebo in this respect. PMID:23326770

  1. Monitoring and assessment of surface water acidification following rewetting of oxidised acid sulfate soils.

    PubMed

    Mosley, Luke M; Zammit, Benjamin; Jolley, Ann-Marie; Barnett, Liz; Fitzpatrick, Rob

    2014-01-01

    Large-scale exposure of acid sulfate soils during a hydrological drought in the Lower Lakes of South Australia resulted in acidification of surface water in several locations. Our aim was to describe the techniques used to monitor, assess and manage these acidification events using a field and laboratory dataset (n = 1,208) of acidic to circum-neutral pH water samples. The median pH of the acidified (pH < 6.5) samples was 3.8. Significant (p < 0.05) increases in soluble metals (Al, Co, Mn, Ni and Zn above guidelines for ecosystem protection), SO4 (from pyrite oxidation), Si (from aluminosilicate dissolution) and Ca (from carbonate dissolution and limestone addition), were observed under the acidic conditions. The log of the soluble metal concentrations, acidity and SO4/Cl ratio increased linearly with pH. The pH, alkalinity and acidity measurements were used to inform aerial limestone dosing events to neutralise acidic water. Field measurements correlated strongly with laboratory measurements for pH, alkalinity and conductivity (r (2) ≥ 0.97) but only moderately with acidity (r (2) = 0.54), which could be due to difficulties in determining the indicator-based field titration endpoint. Laboratory measured acidity correlated well with calculated acidity (r (2) = 0.87, acidity present as Al(III) > H(+) ≈ Mn(II) > Fe(II/III)) but was about 20 % higher on average. Geochemical speciation calculations and XRD measurements indicated that solid phase minerals (schwertmannite and jarosite for Fe and jurbanite for Al) were likely controlling dissolved metal concentrations and influencing measured acidity between pH 2 and 5.

  2. Quantification of phenolic acids and their methylates, glucuronides, sulfates and lactones metabolites in human plasma by LC-MS/MS after oral ingestion of soluble coffee.

    PubMed

    Marmet, Cynthia; Actis-Goretta, Lucas; Renouf, Mathieu; Giuffrida, Francesca

    2014-01-01

    Chlorogenic acids and derivatives like phenolic acids are potentially bioactive phenolics, which are commonly found in many foods. Once absorbed, chlorogenic and phenolic acids are highly metabolized by the intestine and the liver, producing glucuronidated and/or sulphated compounds. These metabolites were analyzed in human plasma using a validated liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) method. After protein precipitation, phenolic acids and their metabolites were extracted by using ethanol and chromatographic separation was achieved by reversed-phase using an Acquity UPLC BEH C18 column combined with a gradient elution system using 1% acetic acid aqueous solution and 1% acetic acid with 100% acetonitrile. The method was able to quantify 56 different compounds including 24 phenolic acids, 4 lactones, 15 sulfates and 13 glucuronides metabolites between 5 and 1000nM in plasma for most of them, except for m-dihydrocoumaric acid, 5-ferulloylquinic-glucuronide, 4-methoxycinnamic acid, 3-phenylpropionic acid, 3-(4-methoxyphenyl)propionic acid (25 to 1000nM) and p-dihydrocoumaric acid (50-1000nM). Values of repeatability and intermediate reproducibility were below 15% of deviation in general, and maximum 20% for the lowest concentrations. The validated method was successfully applied to quantify phenolic acids and their metabolites in plasma obtained after oral ingestion of soluble coffee. In conclusion, the developed and validated method is proved to be very sensitive, accurate and precise for the quantification of these possible dietary phenols.

  3. High-Affinity Transport of Choline-O-Sulfate and Its Use as a Compatible Solute in Bacillus subtilis

    PubMed Central

    Nau-Wagner, Gabriele; Boch, Jens; Le Good, J. Ann; Bremer, Erhard

    1999-01-01

    We report here that the naturally occurring choline ester choline-O-sulfate serves as an effective compatible solute for Bacillus subtilis, and we have identified a high-affinity ATP-binding cassette (ABC) transport system responsible for its uptake. The osmoprotective effect of this trimethylammonium compound closely matches that of the potent and widely employed osmoprotectant glycine betaine. Growth experiments with a set of B. subtilis strains carrying defined mutations in the glycine betaine uptake systems OpuA, OpuC, and OpuD and in the high-affinity choline transporter OpuB revealed that choline-O-sulfate was specifically acquired from the environment via OpuC. Competition experiments demonstrated that choline-O-sulfate functioned as an effective competitive inhibitor for OpuC-mediated glycine betaine uptake, with a Ki of approximately 4 μM. Uptake studies with [1,2-dimethyl-14C]choline-O-sulfate showed that its transport was stimulated by high osmolality, and kinetic analysis revealed that OpuC has high affinity for choline-O-sulfate, with a Km value of 4 ± 1 μM and a maximum rate of transport (Vmax) of 54 ± 3 nmol/min · mg of protein in cells grown in minimal medium with 0.4 M NaCl. Growth studies utilizing a B. subtilis mutant defective in the choline to glycine betaine synthesis pathway and natural abundance 13C nuclear magnetic resonance spectroscopy of whole-cell extracts from the wild-type strain demonstrated that choline-O-sulfate was accumulated in the cytoplasm and was not hydrolyzed to choline by B. subtilis. In contrast, the osmoprotective effect of acetylcholine for B. subtilis is dependent on its biotransformation into glycine betaine. Choline-O-sulfate was not used as the sole carbon, nitrogen, or sulfur source, and our findings thus characterize this choline ester as an effective compatible solute and metabolically inert stress compound for B. subtilis. OpuC mediates the efficient transport not only of glycine betaine and choline-O-sulfate

  4. Process for the extraction of strontium from acidic solutions

    DOEpatents

    Horwitz, E.P.; Dietz, M.L.

    1993-01-01

    The invention is a process for selectively extracting strontium values from aqueous nitric acid waste solutions containing these and other fission product values. The extractant solution is a macrocyclic polyether in an aliphatic hydrocarbon diluent containing a phase modifier. The process will selectively extract strontium values from nitric acid solutions which are up to 6 molar in nitric acid.

  5. Process for the extraction of strontium from acidic solutions

    DOEpatents

    Horwitz, E.P.; Dietz, M.L.

    1994-09-06

    The invention is a process for selectively extracting strontium values from aqueous nitric acid waste solutions containing these and other fission product values. The extractant solution is a macrocyclic polyether in an aliphatic hydrocarbon diluent containing a phase modifier. The process will selectively extract strontium values from nitric acid solutions which are up to 6 molar in nitric acid. 4 figs.

  6. Process for the extraction of strontium from acidic solutions

    DOEpatents

    Horwitz, E. Philip; Dietz, Mark L.

    1994-01-01

    The invention is a process for selectively extracting strontium values from aqueous nitric acid waste solutions containing these and other fission product values. The extractant solution is a macrocyclic polyether in an aliphatic hydrocarbon diluent containing a phase modifier. The process will selectively extract strontium values from nitric acid solutions which are up to 6 molar in nitric acid.

  7. Sulfur geochemistry of hydrothermal waters in Yellowstone National Park: IV Acid-sulfate waters

    USGS Publications Warehouse

    Kirk, Nordstrom D.; Blaine, McCleskey R.; Ball, J.W.

    2009-01-01

    Many waters sampled in Yellowstone National Park, both high-temperature (30-94 ??C) and low-temperature (0-30 ??C), are acid-sulfate type with pH values of 1-5. Sulfuric acid is the dominant component, especially as pH values decrease below 3, and it forms from the oxidation of elemental S whose origin is H2S in hot gases derived from boiling of hydrothermal waters at depth. Four determinations of pH were obtained: (1) field pH at field temperature, (2) laboratory pH at laboratory temperature, (3) pH based on acidity titration, and (4) pH based on charge imbalance (at both laboratory and field temperatures). Laboratory pH, charge imbalance pH (at laboratory temperature), and acidity pH were in close agreement for pH ??10%, a selection process was used to compare acidity, laboratory, and charge balance pH to arrive at the best estimate. Differences between laboratory and field pH can be explained based on Fe oxidation, H2S or S2O3 oxidation, CO2 degassing, and the temperature-dependence of pK2 for H2SO4. Charge imbalances are shown to be dependent on a speciation model for pH values 350 mg/L Cl) decrease as the Cl- concentration increases from boiling which appears inconsistent with the hypothesis of H2S oxidation as a source of hydrothermal SO4. This trend is consistent with the alternate hypothesis of anhydrite solubility equilibrium. Acid-sulfate water analyses are occasionally high in As, Hg, and NH3 concentrations but in contrast to acid mine waters they are low to below detection in Cu, Zn, Cd, and Pb concentrations. Even concentrations of SO4, Fe, and Al are much lower in thermal waters than acid mine waters of the same pH. This difference in water chemistry may explain why certain species of fly larvae live comfortably in Yellowstone's acid waters but have not been observed in acid rock drainage of the same pH.

  8. Examination of Organic Reactions in UT/LS Aerosols: Temperature Dependence in Sulfuric Acid Solution

    NASA Astrophysics Data System (ADS)

    Iraci, L. T.; Michelsen, R. R.

    2004-12-01

    Sulfuric acid has been used for decades as an industrial catalyst for organic reactions, but its parallel role in atmospheric aerosols is relatively unexplored, despite identification of a wide array of organic compounds in particles. Several recent studies have demonstrated possible reactions in acidic particles, generally involving carbonyl groups (C=O) and leading to the formation of larger molecules. Reactions of oxygenated organic compounds in acidic solution are most often studied near room temperature, while the sulfate particles of the upper troposphere and lower stratosphere are significantly colder. Our studies of ethanal (acetaldehyde) suggest that reactivity in ~50 wt% H2SO4 solutions may be enhanced at lower temperatures, contrary to expectations. We will present temperature-dependent results of acid catalyzed condensation reactions, leading to formation of higher molecular weight products. Implications for aerosol composition and reactivity will be discussed.

  9. ADVANCES IN BIOTREATMENT OF ACID MINE DRAINAGE AND BIORECOVERY OF METALS: 2. MEMBRANE BIOREACTOR SYSTEM FOR SULFATE REDUCTION

    EPA Science Inventory

    Acid-mine drainage (AMD) is a severe pollution problem attributed to past mining activities. AMD is an acidic, metal-bearing wastewater generated by the oxidation of metal sulfides to sulfates by Thiobacillus bacteria in both the active and abandoned mining operations. The wastew...

  10. A study of the structure of mixed micellar solutions based on heptaethylene glycol monotetradecyl ether and sodium (lithium) dodecyl sulfate by the small-angle neutron scattering method

    NASA Astrophysics Data System (ADS)

    Rajewska, A.; Medrzycka, K.; Hallmann, E.

    2007-09-01

    The micellization in mixed aqueous systems based on a new nonionic surfactant, namely, heptaethylene glycol monotetradecyl ether (C14E7), and an anionic surfactant, namely, sodium dodecyl sulfate, sodium decyl sulfate, or lithium dodecyl sulfate, is studied by small-angle neutron scattering. Preliminary results of the investigation into the behavior of C14E7 aqueous solutions (at two concentrations, 0.17 and 0.50%) upon addition of small amounts of three different classical anionic surfactants are reported.

  11. Synergistic De-colorization of CanLan-Green Solution with Attapulgite-Ferrous Sulfate Composite Coagulator

    NASA Astrophysics Data System (ADS)

    Han, Hong; Gu, Xu; Li, Dong; Zhou, Sumin; Jiang, Saibo; Lu, Humei

    2010-11-01

    Attapulgite clay has strong adsorptive ability, excellent chemical stability and biological safety, thus has attracted more and more attention in application for environmental field recently. In this study, 0.01 g/L Canlan-Green solution was prepared as treatment target, and the optimal preparation conditions of attapulgite-ferrous sulfate composite coagulator were obtained by methods of heat pretreatment, high temperature calcination and orthogonal experiments; Then the best dosage of composite coagulator for de-colorization of CanLan-Green solution was determined via inspecting factors as pH, reaction temperature, settlement time, reaction time, agitation rate etc. Compared with conventional coagulator ferrous sulfate, composite coagulator possesses advantages of less dosage, excellent decolorization performance, speediness, better settlement ability, cheaper and safer and so on. It proves to be an ideal inorganic composite coagulator choice.

  12. BASE COMPOSITION OF THE DEOXYRIBONUCLEIC ACID OF SULFATE-REDUCING BACTERIA.

    PubMed

    SIGAL, N; SENEZ, J C; LEGALL, J; SEBALD, M

    1963-06-01

    Sigal, Nicole (Laboratoire de Chimie Bactérienne du CNRS, Marseille, France), Jacques C. Senez, Jean Le Gall, and Madeleine Sebald. Base composition of the deoxyribonucleic acid of sulfate-reducing bacteria. J. Bacteriol. 85:1315-1318. 1963-The deoxyribonucleic acid constitution of several strains of sulfate-reducing bacteria has been analytically determined. The results of these studies show that this group of microorganisms includes at least four subgroups characterized by significantly different values of the adenine plus thymine to guanine plus cytosine ratio. The nonsporulated forms with polar flagellation, containing both cytochrome c(3) and desulfoviridin, are divided into two subgroups. One includes the fresh-water, nonhalophilic strains with base ratio from 0.54 to 0.59, and the other includes the halophilic or halotolerant strains with base ratio from 0.74 to 0.77. The sporulated, peritrichous strains without cytochrome and desulfoviridin ("nigrificans" and "orientis") are distinct from the above two types and differ from each other, having base ratios of 1.20 and 1.43, respectively.

  13. New Glucuronic Acid Donors for the Modular Synthesis of Heparan Sulfate Oligosaccharides**

    PubMed Central

    Dhamale, Omkar P.; Zong, Chengli; Al-Mafraji, Kanar

    2014-01-01

    Although hundreds of heparan sulfate (HS) binding proteins have been implicated in a myriad of physiological and pathological processes, very little information is known about ligand requirements for binding and mediating biological activities by these proteins. We report here a streamlined approach for the preparation of modular disaccharide building blocks that will facilitate the assembly of libraries of HS oligosaccharides for structure-activity relationship studies. In particular, we have found that glucuronic acid donors, which usually perform poorly in glycosylations, can give high yields of coupling product when the C-2 hydroxyl is protected with a permanent 4-acetoxy-2,2-dimethyl butanoyl- (PivOAc) or temporary levulinoyl (Lev) ester and the C-4 hydroxyl modified with a selectively removable 2-methylnaphthyl (Nap) ether. It has been shown that the PivOAc ester can be removed without affecting sulfate esters making it an ideal protecting group for HS oligosaccharide assembly. Iduronic acid donors exhibit more favorable glycosyl donating properties and a compound protected with a Lev ester at C-2 and an Fmoc function at the C-4 hydroxyl gave coupling products in high yield. The new donors avoid post-glycosylation oxidation and therefore allow the facile preparation of modular disaccharide building blocks. PMID:24549353

  14. Uremic Retention Solute Indoxyl Sulfate Level Is Associated with Prolonged QTc Interval in Early CKD Patients

    PubMed Central

    Tang, Wei-Hua; Wang, Chao-Ping; Chung, Fu-Mei; Huang, Lynn L. H.; Yu, Teng-Hung; Hung, Wei-Chin; Lu, Li-Fen; Chen, Po-Yuan; Luo, Ching-Hsing; Lee, Kun-Tai; Lee, Yau-Jiunn; Lai, Wen-Ter

    2015-01-01

    Total mortality and sudden cardiac death is highly prevalent in patients with chronic kidney disease (CKD). In CKD patients, the protein-bound uremic retention solute indoxyl sulfate (IS) is independently associated with cardiovascular disease. However, the underlying mechanisms of this association have yet to be elucidated. The relationship between IS and cardiac electrocardiographic parameters was investigated in a prospective observational study among early CKD patients. IS arrhythmogenic effect was evaluated by in vitro cardiomyocyte electrophysiological study and mathematical computer simulation. In a cohort of 100 early CKD patients, patients with corrected QT (QTc) prolongation had higher IS levels. Furthermore, serum IS level was independently associated with prolonged QTc interval. In vitro, the delay rectifier potassium current (IK) was found to be significantly decreased after the treatment of IS in a dose-dependent manner. The modulation of IS to the IK was through the regulation of the major potassium ion channel protein Kv 2.1 phosphorylation. In a computer simulation, the decrease of IK by IS could prolong the action potential duration (APD) and induce early afterdepolarization, which is known to be a trigger mechanism of lethal ventricular arrhythmias. In conclusion, serum IS level is independently associated with the prolonged QTc interval in early CKD patients. IS down-regulated IK channel protein phosphorylation and the IK current activity that in turn increased the cardiomyocyte APD and QTc interval in vitro and in the computer ORd model. These findings suggest that IS may play a role in the development of arrhythmogenesis in CKD patients. PMID:25893644

  15. Alleviating aluminum toxicity in an acid sulfate soil from Peninsular Malaysia by calcium silicate application

    NASA Astrophysics Data System (ADS)

    Elisa, A. A.; Ninomiya, S.; Shamshuddin, J.; Roslan, I.

    2016-03-01

    In response to human population increase, the utilization of acid sulfate soils for rice cultivation is one option for increasing production. The main problems associated with such soils are their low pH values and their associated high content of exchangeable Al, which could be detrimental to crop growth. The application of soil amendments is one approach for mitigating this problem, and calcium silicate is an alternative soil amendment that could be used. Therefore, the main objective of this study was to ameliorate soil acidity in rice-cropped soil. The secondary objective was to study the effects of calcium silicate amendment on soil acidity, exchangeable Al, exchangeable Ca, and Si content. The soil was treated with 0, 1, 2, and 3 Mg ha-1 of calcium silicate under submerged conditions and the soil treatments were sampled every 30 days throughout an incubation period of 120 days. Application of calcium silicate induced a positive effect on soil pH and exchangeable Al; soil pH increased from 2.9 (initial) to 3.5, while exchangeable Al was reduced from 4.26 (initial) to 0.82 cmolc kg-1. Furthermore, the exchangeable Ca and Si contents increased from 1.68 (initial) to 4.94 cmolc kg-1 and from 21.21 (initial) to 81.71 mg kg-1, respectively. Therefore, it was noted that calcium silicate was effective at alleviating Al toxicity in acid sulfate, rice-cropped soil, yielding values below the critical level of 2 cmolc kg-1. In addition, application of calcium silicate showed an ameliorative effect as it increased soil pH and supplied substantial amounts of Ca and Si.

  16. Sulfate- and sialic acid-containing glycolipids inhibit DNA polymerase alpha activity.

    PubMed

    Simbulan, C M; Taki, T; Tamiya-Koizumi, K; Suzuki, M; Savoysky, E; Shoji, M; Yoshida, S

    1994-03-16

    The effects of various glycolipids on the activity of immunoaffinity-purified calf thymus DNA polymerase alpha were studied in vitro. Preincubation with sialic acid-containing glycolipids, such as sialosylparagloboside (SPG), GM3, GM1, and GD1a, and sulfatide (cerebroside sulfate ester, CSE) dose-dependently inhibited the activity of DNA polymerase alpha, while other glycolipids, as well as free sphingosine and ceramide did not. About 50% inhibition was achieved by preincubating the enzyme with 2.5 microM of CSE, 50 microM of SPG or GM3, and 80 microM of GM1. Inhibition was noncompetitive with both the DNA template and the substrate dTTP, as well as with the other dNTPs. Since the inhibition was largely reversed by the addition of 0.05% Nonidet P40, these glycolipids may interact with the hydrophobic region of the enzyme protein. Apparently, the sulfate moiety in CSE and the sialic acid moiety in gangliosides were essential for the inhibition since neither neutral glycolipids (i.e., glucosylceramide, galactosylceramide, lactosylceramide) nor asialo-gangliosides (GA1 and GA2) showed any inhibitory effect. Furthermore, the ceramide backbone was also found to be necessary for maximal inhibition since the inhibition was largely abolished by substituting the lipid backbone with cholesterol. Increasing the number of sialic acid moieties per molecule further enhanced the inhibition, while elongating the sugar chain diminished it. It was clearly shown that the N-acetyl residue of the sialic acid moiety is particularly essential for inhibition by both SPG and GM3 because the loss of this residue or substitution with a glycolyl residue completely negated their inhibitory effect on DNA polymerase alpha activity.

  17. Distribution of iron- and sulfate-reducing bacteria across a coastal acid sulfate soil (CASS) environment: implications for passive bioremediation by tidal inundation

    PubMed Central

    Ling, Yu-Chen; Bush, Richard; Grice, Kliti; Tulipani, Svenja; Berwick, Lyndon; Moreau, John W.

    2015-01-01

    Coastal acid sulfate soils (CASS) constitute a serious and global environmental problem. Oxidation of iron sulfide minerals exposed to air generates sulfuric acid with consequently negative impacts on coastal and estuarine ecosystems. Tidal inundation represents one current treatment strategy for CASS, with the aim of neutralizing acidity by triggering microbial iron- and sulfate-reduction and inducing the precipitation of iron-sulfides. Although well-known functional guilds of bacteria drive these processes, their distributions within CASS environments, as well as their relationships to tidal cycling and the availability of nutrients and electron acceptors, are poorly understood. These factors will determine the long-term efficacy of “passive” CASS remediation strategies. Here we studied microbial community structure and functional guild distribution in sediment cores obtained from 10 depths ranging from 0 to 20 cm in three sites located in the supra-, inter- and sub-tidal segments, respectively, of a CASS-affected salt marsh (East Trinity, Cairns, Australia). Whole community 16S rRNA gene diversity within each site was assessed by 454 pyrotag sequencing and bioinformatic analyses in the context of local hydrological, geochemical, and lithological factors. The results illustrate spatial overlap, or close association, of iron-, and sulfate-reducing bacteria (SRB) in an environment rich in organic matter and controlled by parameters such as acidity, redox potential, degree of water saturation, and mineralization. The observed spatial distribution implies the need for empirical understanding of the timing, relative to tidal cycling, of various terminal electron-accepting processes that control acid generation and biogeochemical iron and sulfur cycling. PMID:26191042

  18. Using Australian Acidic Playa Lakes as Analogs for Phyllosilicate and Sulfate Depositional Environments on Mars

    NASA Astrophysics Data System (ADS)

    Baldridge, A. M.; Michalski, J.; Kargel, J.; Hook, S.; Marion, G.; Crowley, J.; Bridges, N.; Brown, A.; Ribeiro da Luz, B.; de Souza Filho, C. R.; Thomson, B.

    2008-12-01

    Recent work on the origin of martian sulfates and their relationship to phyllosilicate deposits suggest that these deposits formed in different eras of Mars' history, under distinct environmental conditions. In southwestern Meridiani Planum phyllosilicates exist in close proximity to sulfate deposits. One possible explanation for this relationship is that it is an unconformable stratigraphic sequence, representing a significant change in aqueous geochemical conditions over time. Specifically, it may be interpreted to record a change in environment from neutral pH aqueous alteration in the Noachian to an acidic evaporitic system in the late Noachian to the Hesperian. On Earth, two different geochemical systems need not be evoked to explain such chemical variation. Acidic playa lakes in Western Australia have large pH differences separated by only a few tens of meters and demonstrate how highly variable chemistries can coexist over short distances in natural environments. Playa lakes on Earth tend to be dominated by lateral flow of water and salts leading to lateral chemical variation. Heterogeneity of playa mineralogy in Australia is due to the varied source rocks of brines and the mixing of dilute oxidizing brines and freshwater with the saturated evaporitic brines. This is evidenced by the ferricretes in the near-shore environment and more soluble phases in basin interiors. Playa lakes on Mars would be much larger than their terrestrial counterparts, leading to the prevalence of large-scale surface and crustal advection of water and salt rather than short-distance lateral flow, except at lake boundaries. Little or no influx of freshwater would preclude the formation of playa rim (e.g., crater rim) ferricretes and silcretes. Instead, we expect to see mainly vertical facies changes, and any diachronous lateral facies changes are expected to occur on very large spatial scales. Comparison of high spatial resolution, hyperspectral airborne data for Australian playa

  19. Measuring and modeling the salting-out effect in ammonium sulfate solutions.

    PubMed

    Wang, Chen; Lei, Ying Duan; Endo, Satoshi; Wania, Frank

    2014-11-18

    The presence of inorganic salts significantly influences the partitioning behavior of organic compounds between environmentally relevant aqueous phases, such as seawater or aqueous aerosol, and other, nonaqueous phases (gas phase, organic phase, etc.). In this study, salting-out coefficients (or Setschenow constants) (KS [M(-1)]) for 38 diverse neutral compounds in ammonium sulfate ((NH4)2SO4) solutions were measured using a shared headspace passive dosing method and a negligible depletion solid phase microextraction technique. The measured KS were all positive, varied from 0.216 to 0.729, and had standard errors in the range of 0.006-0.060. Compared to KS for sodium chloride (NaCl) in the literature, KS values for (NH4)2SO4 are always higher for the same compound, suggesting a higher salting-out effect of (NH4)2SO4. A polyparameter linear free energy relationship (pp-LFER) for predicting KS in (NH4)2SO4 solutions was generated using the experimental data for calibration. pp-LFER predicted KS agreed well with measured KS reported in the literature. KS for (NH4)2SO4 was also predicted using the quantum-chemical COSMOtherm software and the thermodynamic model AIOMFAC. While COSMOtherm generally overpredicted the experimental KS, predicted and experimental values were correlated. Therefore, a fitting factor needs to be applied when using the current version of COSMOtherm to predict KS. AIOMFAC tends to underpredict the measured KS((NH4)2SO4) but always overpredicts KS(NaCl). The prediction error is generally larger for KS(NaCl) than for KS((NH4)2SO4). AIOMFAC also predicted a dependence of KS on the salt concentrations, which is not observed in the experimental data. In order to demonstrate that the models developed and calibrated in this study can be applied to estimate Setschenow coefficients for atmospherically relevant compounds involved in secondary organic aerosol formation based on chemical structure alone, we predicted and compared KS for selected

  20. Recovery and separation of sulfuric acid and iron from dilute acidic sulfate effluent and waste sulfuric acid by solvent extraction and stripping.

    PubMed

    Qifeng, Wei; Xiulian, Ren; Jingjing, Guo; Yongxing, Chen

    2016-03-05

    The recovery and simultaneous separation of sulfuric acid and iron from dilute acidic sulfate effluent (DASE) and waste sulfuric acid (WSA) have been an earnest wish for researchers and the entire sulfate process-based titanium pigment industry. To reduce the pollution of the waste acid and make a comprehensive use of the iron and sulfuric acid in it, a new environmentally friendly recovery and separation process for the DASE and the WSA is proposed. This process is based on the reactive extraction of sulfuric acid and Fe(III) from the DASE. Simultaneously, stripping of Fe(III) is carried out in the loaded organic phase with the WSA. Compared to the conventional ways, this innovative method allows the effective extraction of sulfuric acid and iron from the DASE, and the stripping of Fe(III) from the loaded organic phase with the WSA. Trioctylamine (TOA) and tributyl phosphate (TBP) in kerosene (10-50%) were used as organic phases for solvent extraction. Under the optimal conditions, about 98% of Fe(III) and sulfuric acid were removed from the DASE, and about 99.9% of Fe(III) in the organic phase was stripped with the WSA.

  1. Speciation and Structural Properties of Hydrothermal Solutions of Sodium and Potassium Sulfate Studied by Molecular Dynamics Simulations.

    PubMed

    Reimer, Joachim; Vogel, Frédéric; Steele-MacInnis, Matthew

    2016-05-18

    Aqueous solutions of salts at elevated pressures and temperatures play a key role in geochemical processes and in applications of supercritical water in waste and biomass treatment, for which salt management is crucial for performance. A major question in predicting salt behavior in such processes is how different salts affect the phase equilibria. Herein, molecular dynamics (MD) simulations are used to investigate molecular-scale structures of solutions of sodium and/or potassium sulfate, which show contrasting macroscopic behavior. Solutions of Na-SO4 exhibit a tendency towards forming large ionic clusters with increasing temperature, whereas solutions of K-SO4 show significantly less clustering under equivalent conditions. In mixed systems (Nax K2-x SO4 ), cluster formation is dramatically reduced with decreasing Na/(K+Na) ratio; this indicates a structure-breaking role of K. MD results allow these phenomena to be related to the characteristics of electrostatic interactions between K(+) and SO4 (2-) , compared with the analogous Na(+) -SO4 (2-) interactions. The results suggest a mechanism underlying the experimentally observed increasing solubility in ternary mixtures of solutions of Na-K-SO4 . Specifically, the propensity of sodium to associate with sulfate, versus that of potassium to break up the sodium-sulfate clusters, may affect the contrasting behavior of these salts. Thus, mutual salting-in in ternary hydrothermal solutions of Na-K-SO4 reflects the opposing, but complementary, natures of Na-SO4 versus K-SO4 interactions. The results also provide clues towards the reported liquid immiscibility in this ternary system.

  2. Design and Construction of Experiment for Direct Electron Irradiation of Uranyl Sulfate Solution: Bubble Formation and Thermal Hydraulics Studies

    SciTech Connect

    Chemerisov, Sergey; Gromov, Roman; Makarashvili, Vakho; Heltemes, Thad; Sun, Zaijing; Wardle, Kent E.; Bailey, James; Quigley, Kevin; Stepinski, Dominique; Vandegrift, George

    2014-10-01

    Argonne is assisting SHINE Medical Technologies in developing SHINE, a system for producing fission-product 99Mo using a D/T-accelerator to produce fission in a non-critical target solution of aqueous uranyl sulfate. We have developed an experimental setup for studying thermal-hydraulics and bubble formation in the uranyl sulfate solution to simulate conditions expected in the SHINE target solution during irradiation. A direct electron beam from the linac accelerator will be used to irradiate a 20 L solution (sector of the solution vessel). Because the solution will undergo radiolytic decomposition, we will be able to study bubble formation and dynamics and effects of convection and temperature on bubble behavior. These experiments will serve as a verification/ validation tool for the thermal-hydraulic model. Utilization of the direct electron beam for irradiation allows homogeneous heating of a large solution volume and simplifies observation of the bubble dynamics simultaneously with thermal-hydraulic data collection, which will complement data collected during operation of the miniSHINE experiment. Irradiation will be conducted using a 30-40 MeV electron beam from the high-power linac accelerator. The total electron-beam power will be 20 kW, which will yield a power density on the order of 1 kW/L. The solution volume will be cooled on the front and back surfaces and central tube to mimic the geometry of the proposed SHINE solution vessel. Also, multiple thermocouples will be inserted into the solution vessel to map thermal profiles. The experimental design is now complete, and installation and testing are in progress.

  3. Short-term endproducts of sulfate reduction in a salt marsh: Formation of acid volatile sulfides, elemental sulfur, and pyrite

    NASA Astrophysics Data System (ADS)

    King, Gary M.; Howes, B. L.; Dacey, J. W. H.

    1985-07-01

    Rates of sulfate reduction, oxygen uptake and carbon dioxide production in sediments from a short Spartina alterniflora zone of Great Sippewissett Marsh were measured simultaneously during late summer. Surface sediments (0-2 cm) were dominated by aerobic metabolism which accounted for about 45% of the total carbon dioxide production over 0-15 cm. Rates of sulfate reduction agreed well with rates of total carbon dioxide production below 2 cm depth indicating that sulfate reduction was the primary pathway for sub-surface carbon metabolism. Sulfate reduction rates were determined using a radiotracer technique coupled with a chromous chloride digestion and carbon disulfide extraction of the sediment to determine the extent of formation of radiolabelled elemental sulfur and pyrite during shortterm (48 hr) incubations. In the surface 10 cm of the marsh sediments investigated, about 50% of the reduced radiosulfur was recovered as dissolved or acid volatile sulfides, 37% as carbon disulfide extractable sulfur, and only about 13% was recovered in a fraction operationally defined as pyrite. Correlations between the extent of sulfate depletion in the marsh sediments and the concentrations of dissolved and acid volatile sulfides supported the results of the radiotracer work. Our data suggest that sulfides and elemental sulfur may be major short-term end-products of sulfate reduction in salt marshes.

  4. Origin of dimethylsulfide, non-sea-salt sulfate, and methanesulfonic acid in eastern Antarctica

    NASA Astrophysics Data System (ADS)

    Cosme, E.; Hourdin, F.; Genthon, C.; Martinerie, P.

    2005-02-01

    Ignoring the origin of atmospheric chemicals is often a strong limitation to the full interpretation of their measurement. In this article, this question is addressed in the case of the sulfur species in Antarctica, with an original method of retrotransport of tracers. The retrotransport model is derived from the Laboratoire de Météorologie Dynamique Zoom-Tracers (LMD-ZT) atmospheric general circulation model, optimized for polar climate and expanded to simulate atmospheric sulfur chemistry. For two East Antarctic scientific stations (Dumont d'Urville and Vostok) the effects of transport and chemistry and the influence of oceanic, volcanic, and anthropogenic sources on dimethylsulfide (DMS), non-sea-salt (nss) sulfate, and methanesulfonic acid (MSA) concentrations are evaluated in summer and winter. The oceanic source largely dominates, but other sources can episodically be significant. The meridional origin and the age of DMS, MSA, and biogenic nss sulfate are also estimated. The latitudes of origin of MSA and nss sulfate are similar in summer, but they differ markedly in winter. This is a signature of their different chemical production scheme. Also, the interannual variability of the origin of the sulfur species at Vostok is weak compared to that at Dumont d'Urville. Acknowledging that the DMS concentrations in the ocean have no interannual variability in the model, this result suggests unsurprisingly that inland Antarctic stations may be better observation sites to monitor large-scale DMS bioproductivity variability than coastal sites are. The combination of slower chemistry and more intense atmospheric circulation in winter leads to unexpected results, such as a younger DMS in winter than in summer at Vostok.

  5. Free radical mechanisms for the oxidation of substituted ascorbates. A pulse radiolysis study of L-ascorbic acid-2-sulfate

    SciTech Connect

    Cabelli, D.E.; Comstock, D.A.; Bielski, B.H.J.

    1983-09-01

    The oxidations of L-ascorbate 2-sulfate by Br/sub 2//sup -/ and OH radicals generated in aqueous solutions (pH 4.5 to 9.5) were studied by pulse radiolysis. The (2-SO/sub 4/A)./sup -/ radical, generated in an electron transfer reaction between Br/sub 2//sup -/ and the parent compound, loses sulfate (tau approx. 500 ..mu..sec) to give ascorbate free radical (A./sup -/) with a G(A./sup -/) = 2.0. The oxidation of L-ascorbate 2sulfate by OH radicals is complex, yielding both (2-SO/sub 4/A)/sup -/ and OH radical adducts. Some of these transients subsequently yield A./sup -/. HPLC studies corroborate the overall mechanism postulated for the oxidation of L-ascorbate 2-sulfate by OH radicals.

  6. Evidence for Acid-Sulfate Alteration in the Pahrump Hills Region, Gale Crater, Mars

    NASA Astrophysics Data System (ADS)

    Rampe, E. B.; Ming, D. W.; Vaniman, D. T.; Blake, D. F.; Chipera, S.; Morris, R. V.; Bish, D. L.; Cavanagh, P.; Achilles, C.; Bristow, T.; Fairen, A.; Morrison, S. M.; Treiman, A. H.; Crisp, J. A.; Downs, R. T.; Farmer, J. D.; Fendrich, K.; Morookian, J.

    2015-12-01

    The Pahrump Hills region of Gale crater is a ~12 m thick section of sedimentary rock in the Murray formation, interpreted as the basal geological unit of Mount Sharp. The Mars Science Laboratory, Curiosity, arrived at the Pahrump Hills in September 2014 and performed a detailed six-month investigation of the sedimentary structures, geochemistry, and mineralogy of the area. During the campaign, Curiosity drilled and delivered three mudstone samples (targets Confidence Hills, Mojave 2, and Telegraph Peak) to its internal instruments, including the CheMin XRD/XRF. Results from CheMin show that these samples have variable amounts of plagioclase, pyroxene, iron oxides, jarosite, phyllosilicates, cristobalite, and X-ray amorphous material. The presence of jarosite in all samples indicates these rocks were affected by acid-sulfate alteration, and the mineralogical and geochemical trends observed through the section may give more insight into this process. Geochemical data measured by APXS show enrichment in Si and depletion in Mg moving up section. CheMin data show that cristobalite is more abundant up section, whereas pyroxene and phyllosilicates are more abundant at the bottom of the section. Based on mineralogical and geochemical trends and diagenetic features observed in the Pahrump Hills, we hypothesize that the sediments were altered in-situ by acid-sulfate fluids moving down from the top of the section to leach mobile elements, dissolve the minerals most susceptible to acidic alteration, and precipitate secondary silica at the top of the section. Alternative interpretations of the observed mineralogical and geochemical data are possible, including the hypothesis that the redox conditions of the body of water in which the sediments were deposited changed over time.

  7. Microwave-assisted digestion using nitric acid for heavy metals and sulfated ash testing in active pharmaceutical ingredients.

    PubMed

    Pluhácek, T; Hanzal, J; Hendrych, J; Milde, D

    2016-04-01

    The monitoring of inorganic impurities in active pharmaceutical ingredients plays a crucial role in the quality control of the pharmaceutical production. The heavy metals and residue on ignition/sulfated ash methods employing microwave-assisted digestion with concentrated nitric acid have been demonstrated as alternatives to inappropriate compendial methods recommended in United States Pharmacopoeia (USP) and European Pharmacopoeia (Ph. Eur.). The recoveries using the heavy metals method ranged between 89% and 122% for nearly all USP and Ph. Eur. restricted elements as well as the recoveries of sodium sulfate spikes were around 100% in all tested matrices. The proposed microwave-assisted digestion method allowed simultaneous decomposition of 15 different active pharmaceutical ingredients with sample weigh up to 1 g. The heavy metals and sulfated ash procedures were successfully applied to the determination of heavy metals and residue on ignition/sulfated ash content in mycophenolate mofetil, nicergoline and silymarin.

  8. Modeling the crystal distribution of lead-sulfate in lead-acid batteries with 3D spatial resolution

    NASA Astrophysics Data System (ADS)

    Huck, Moritz; Badeda, Julia; Sauer, Dirk Uwe

    2015-04-01

    For the reliability of lead-acid batteries it is important to have an accurate prediction of its response to load profiles. A model for the lead-sulfate growth is presented, which is embedded in a physical-chemical model with 3D spatial resolution is presented which is used for analyzing the different mechanism influencing the cell response. One import factor is the chemical dissolution and precipitation of lead-sulfate, since its dissolution speed limits the charging reaction and the accumulation of indissolvable of lead-sulfate leads to capacity degradation. The cell performance/behavior is not only determined by the amount of the sulfate but also by the radii and distribution of the crystals. The presented model can be used to for an improved understanding of the interaction of the different mechanisms.

  9. Stannous sulfate as an electrolyte additive for lead acid battery made from a novel ultrafine leady oxide

    NASA Astrophysics Data System (ADS)

    Wang, Qin; Liu, Jianwen; Yang, Danni; Yuan, Xiqing; Li, Lei; Zhu, Xinfeng; Zhang, Wei; Hu, Yucheng; Sun, Xiaojuan; Liang, Sha; Hu, Jingping; Kumar, R. Vasant; Yang, Jiakuan

    2015-07-01

    The effects of SnSO4 as an electrolyte additive on the microstructure of positive plate and electrochemical performance of lead acid battery made from a novel leady oxide are investigated. The novel leady oxide is synthesized through leaching of spent lead paste in citric acid solution. The novel leady oxides are used to prepare working electrode (WE) subjected to electrochemical cyclic voltammetry (CV) tests. Moreover, the novel leady oxides are used as active materials of positive plate assembled as a testing battery of 1.85 A h capacity. In CV tests, SEM/EDX results show that the major crystalline phase of the paste in WE after CV cycles is PbSO4. The larger column-shaped PbSO4 crystals easily generate in the paste of WE without an electrolyte additive of SnSO4. However, PbSO4 crystals significantly become smaller with the addition of SnSO4 in the electrolyte. In batteries testing, SEM results show that an electrolyte additive of SnSO4 could effectively decrease PbO2 particle size in the positive active materials of the teardown battery at the end of charging procedure. It is indicated that an electrolyte additive of SnSO4 could have a positive influence on restraining larger particles of irreversible sulfation in charge/discharge cycles of battery testing.

  10. Sonolysis of Short-Chain Organic Dicarboxylic Acid Solutions

    NASA Astrophysics Data System (ADS)

    Naruke, Yukio; Harada, Hisashi

    2011-07-01

    Sonolyses of C4 (carbon number 4) dicarboxylic acids (succinic acid, maleic acid, and fumaric acid) were performed in aqueous solution. They changed one into the other during sonication, affording carbon-number-conserving transformations. Maleic acid and fumaric acid were produced from saccinic acid by dehydrogenation. Furthermore, malic acid and tartaric acid were obtained by hydroxylation. The sonochemical reaction processes are discussed in terms of the time dependences of products and the addition of radical scavengers. In addition, mutual isomerization of fumaric acid and maleic acid was observed during sonication without the use of mediators.

  11. Uranyl fluoride luminescence in acidic aqueous solutions

    SciTech Connect

    Beitz, J.V.; Williams, C.W.

    1996-08-01

    Luminescence emission spectra and decay rates are reported for uranyl species in acidic aqueous solutions containing HF or added NaF. The longest luminescence lifetime, 0.269 {+-} 0.006 ms, was observed from uranyl in 1 M HF + 1 M HClO{sub 4} at 296 K and decreased with increasing temperature. Based on a luminescence dynamics model that assumes equilibrium among electronically excited uranyl fluoride species and free fluoride ion, this long lived uranyl luminescence in aqueous solution is attributed primarily to UO{sub 2}F{sub 2}. Studies on the effect of added LiNO{sub 3} or Na{sub 2}WO{sub 4}{center_dot}2H{sub 2}O showed relatively weak quenching of uranyl fluoride luminescence which suggests that high sensitivity determination of the UF{sub 6} content of WF{sub 6} gas should be feasible via uranyl luminescence analysis of hydrolyzed gas samples of impure WF{sub 6}.

  12. Pharmacokinetics of wood creosote: glucuronic acid and sulfate conjugation of phenolic compounds.

    PubMed

    Ogata, N; Matsushima, N; Shibata, T

    1995-09-01

    Wood creosote, principally a mixture of non-, alkyl- and/or alkoxy-substituted phenolic compounds, was orally administered to adult male volunteers to determine its metabolites and pharmacokinetic parameters. After a 133-mg single dose, its major constituents (i.e. phenol 15 mg, guaiacol 32 mg, p-cresol 18 mg and creosol 24 mg) were found in peripheral venous blood and urine, mostly as glucuronic acid and, except for creosol, as sulfate conjugates. Low concentrations of unconjugated phenols were also detected. The metabolites in the serum started to increase 15 min after the dose, and they reached their maximum concentrations 30 min after administration. The maximum concentrations of glucuronides were 0.18 +/- 0.07, 0.91 +/- 0.38, 0.33 +/- 0.18 and 0.47 +/- 0.23 mg/l; those of sulfates were 0.16 +/- 0.06, 0.22 +/- 0.09, 0.17 +/- 0.07 and < 0.04 mg/l for phenol, guaiacol, p-cresol and creosol, respectively. The 24-hour urinary recoveries of the sum of each compound and its metabolites were 75 +/- 35, 45 +/- 36, 103 +/- 51 and 74 +/- 36%, in the above order. The presence of guaiacol glucuronide in blood and urine was directly verified by its isolation and structure analyses.

  13. Influence of metal ions and pH on the hydraulic properties of potential acid sulfate soils

    NASA Astrophysics Data System (ADS)

    Le, T. M. H.; Collins, R. N.; Waite, T. D.

    2008-07-01

    SummaryAcid sulfate soils (ASS) cover extensive areas of east Australian coastal floodplains. Upon oxidation, these hydromorphic pyritic sediments produce large quantities of sulfuric acid. In addition, due to their geographic location, these soils may also come in contact with high ionic strength estuarine tidal waters. As a result, there is typically a large variation in acidity (pH) and cation concentrations in soil porewaters and adjacent aquatic systems (e.g., agricultural field drains, rivers, estuaries, etc.). Acid sulfate soils, especially from the unoxidized gelatinous deeper layers, contain a relatively high proportion of montmorillonite, which is wellknown for its shrink-swell properties. Variations in cation concentrations, including H3O+, can influence montmorillonite platelet interactions and may, thus, also significantly affect the hydraulic conductivity of materials containing this clay. In this paper we report on the effect of four common cations, at reasonable environmental concentrations, on the hydraulic properties of potential (unoxidized) acid sulfate soil materials. The natural system was simplified by examining individually the effects of each cation (H+, Ca2+, Fe2+ and Na+) on a soil-water suspension in a filtration cell unit. Moisture ratio, hydraulic conductivity and the consolidation coefficient of the deposited filter cakes were calculated using material coordinates theory. The results indicate that the hydraulic conductivity of potential acid sulfate soils increases at low pH and with cation concentration. Although an increase in the charge of amphoteric edge groups on montmorillonite clays may result in some aggregation between individual clay platelets, we conclude that the extent of these changes are unlikely to cause significant increases in the transportation of acidity (and contaminants) through potential acid sulfate soils as the hydraulic conductivity of these materials remain low (<10-9 m/s) at pH and ionic conditions normally

  14. Crystallization of aqueous inorganic-malonic acid particles: nucleation rates, dependence on size, and dependence on the ammonium-to-sulfate ratio.

    PubMed

    Parsons, Matthew T; Riffell, Jenna L; Bertram, Allan K

    2006-07-06

    Using an electrodynamic balance, we determined the relative humidity (RH) at which aqueous inorganic-malonic acid particles crystallized, with ammonium sulfate ((NH(4))(2)SO(4)), letovicite ((NH(4))(3)H(SO(4))(2)), or ammonium bisulfate (NH(4)HSO(4)) as the inorganic component. The results for (NH(4))(2)SO(4)-malonic acid particles and (NH(4))(3)H(SO(4))(2)-malonic acid particles show that malonic acid decreases the crystallization RH of the inorganic particles by less than 7% RH when the dry malonic acid mole fraction is less than 0.25. At a dry malonic acid mole fraction of about 0.5, the presence of malonic acid can decrease the crystallization RH of the inorganic particles by up to 35% RH. For the NH(4)HSO(4)-malonic acid particles, the presence of malonic acid does not significantly modify the crystallization RH of the inorganic particles for the entire range of dry malonic acid mole fractions studied; in all cases, either the particles did not crystallize or the crystallization RH was close to 0% RH. Size dependent measurements show that the crystallization RH of aqueous (NH(4))(2)SO(4) particles is not a strong function of particle volume. However, for aqueous (NH(4))(2)SO(4)-malonic acid particles (with dry malonic acid mole fraction = 0.36), the crystallization RH is a stronger function of particle volume, with the crystallization RH decreasing by 6 +/- 3% RH when the particle volume decreases by an order of magnitude. To our knowledge, these are the first size dependent measurements of the crystallization RH of atmospherically relevant inorganic-organic particles. These results suggest that for certain organic mole fractions the particle size and observation time need to be considered when extrapolating laboratory crystallization results to atmospheric scenarios. For aqueous (NH(4))(2)SO(4) particles, the homogeneous nucleation rate data are a strong function of RH, but for aqueous (NH(4))(2)SO(4)-malonic acid particles (with dry organic mole fraction = 0

  15. Ion Association in Hydrothermal Sodium Sulfate Solutions Studied by Modulated FT-IR-Raman Spectroscopy and Molecular Dynamics.

    PubMed

    Reimer, Joachim; Steele-MacInnis, Matthew; Wambach, Jörg M; Vogel, Frédéric

    2015-07-30

    Saline aqueous solutions at elevated pressures and temperatures play an important role in processes such as supercritical water oxidation (SCWO) and supercritical water gasification (SCWG), as well as in natural geochemical processes in Earth and planetary interiors. Some solutions exhibit a negative temperature coefficient of solubility at high temperatures, thereby leading to salt precipitation with increasing temperature. Using modulated FT-IR Raman spectroscopy and classical molecular dynamics simulations (MD), we studied the solute speciation in solutions of 10 wt % Na2SO4, at conditions close to the saturation limit. Our experiments reveal that ion pairing and cluster formation are favored as solid saturation is approached, and ionic clusters form prior to the precipitation of solid sulfate. The proportion of such clusters increases as the phase boundary is approached either by decreasing pressure or by increasing temperature in the vicinity of the three-phase (vapor-liquid-solid) curve.

  16. The effect of ascorbic acid oxidation on the incorporation of sulfate by slices of calf costal cartilage.

    PubMed

    KLEBANOFF, S J; DZIEWIATKOWSKI, D D; OKINAKA, G J

    1958-11-20

    A marked inhibition of the incorporation of S(35)-sulfate by normal calf costal cartilage was produced by potassium ascorbate in the presence of catalytic amounts of cupric ions. The effect of the various components of the ascorbic acid oxidizing system (potassium ascorbate, cupric ions, cuprous ions, hydrogen peroxide, dehydroascorbic acid) was investigated. The results of experiments in which hydrogen peroxide, catalase, or sodium azide were used singly or in combination suggest that the inhibition produced by the ascorbic acid oxidizing system is due, to a considerable extent, to the production of hydrogen peroxide. Dehydroascorbic acid was also found to inhibit the incorporation of S(35)-sulfate by cartilage slices. However, the gradual fall in pH which resulted from the addition of dehydroascorbic acid could account to a large extent for the inhibitory effect observed because the incorporation of S(35)-sulfate by cartilage slices decreases sharply as the pH is lowered. The incorporation of S(35)-sulfate by cartilage slices is inhibited also by increasing the concentration of phosphate.

  17. Protonation of Alcohols in Sulfuric Acid Solutions at UT/LS Conditions

    NASA Astrophysics Data System (ADS)

    Michelsen, R. R.; Vernier, K.; Axson, J.; Morley, D.

    2007-12-01

    The protonation of several small alcohols (ethanol, 2-propanol, and 1-butanol) in cold sulfuric acid aqueous solutions was measured using variable temperature 13C nuclear magnetic resonance (NMR) spectroscopy. The acidity of the sulfuric acid + deuterium oxide solutions ranged from 43 to 81 weight percent (wt %) H2SO4. The pKBH+ values, which are a measure of the acidity of each alcohol, range from -2.0 for butanol at room temperature to -2.2 for ethanol at -20°C. The protonation enthalpies of the three alcohols over the temperature range of 22°C to -35°C were found to be small and negative, ranging from -1.8 kJ mol-1 for 2-propanol to -2.3 kJ mol-1 for ethanol. A small, negative protonation enthalpy means that the degree of protonation of the alcohol slightly decreases as temperature decreases. The pKBH+values and protonation enthalpies are used to predict the form of dissolved alcohols in sulfate aerosols. For typical upper troposphere/lower stratosphere (UT/LS) conditions (40-70 wt % H2SO4 and 220 K), all three alcohols increase from approximately 10% protonated in 40 wt % H2SO4 to over 60% protonated in 70 wt % H2SO4. The percent of protonated alcohol depends more strongly on m*, the slope factor of the excess acidity treatment, than on pKBH+ values. This relationship may reflect solvation effects. The treatment of strongly acidic, non-ideal solutions as applied to organic solutes in sulfate aerosol particles will be discussed.

  18. Synergistic inhibition of Listeria monocytogenes in vitro through the combination of octanoic acid and acidic calcium sulfate.

    PubMed

    Brandt, Alex L; Castillo, Alejandro; Harris, Kerri B; Keeton, Jimmy T; Hardin, Margaret D; Taylor, T Matthew

    2011-01-01

    It has been hypothesized that inhibition of foodborne pathogens can be enhanced by using antimicrobials in combination. A broth dilution assay was devised to determine whether inhibition of Listeria monocytogenes exposed to the combination of the fatty acid octanoic acid (OCT) and the organic acid-containing antimicrobial acidic calcium sulfate (ACS) was enhanced compared with the inhibition of the pathogen exposed to either antimicrobial applied singly. MICs for OCT and ACS were 25.00 μg/g and 1.56 ml/liter, respectively, for all strains of the pathogen tested. Fractional inhibitory concentrations (FICs) from the combination exposures were calculated for use in characterizing the antimicrobial interaction as antagonistic, additive indifferent, or synergistic with respect to L. monocytogenes inhibition. Combining OCT and ACS resulted in observed synergistic inhibition of L. monocytogenes; isobolograms for all strains curved toward the origin, and FIC indices (FIC(I)s) were <1.0. Future investigations of the antimicrobial combination should focus on determining the mechanism of action of combined antimicrobials and the levels of antimicrobials required for pathogen inhibition on the surfaces of ready-to-eat meats.

  19. Ferrous iron oxidation by Thiobacillus ferrooxidans: inhibition with benzoic acid, sorbic acid and sodium lauryl sulfate

    SciTech Connect

    Onysko, S.J.

    1984-07-01

    Acid mine drainage is formed by the weathering or oxidation of pyritic material exposed during coal mining. The rate of pyritic material oxidation can be greatly accelerated by certain acidophilic bacteria such as Thiobacillus ferrooxidans which catalyse the oxidation of ferrous to ferric iron. A number of organic compounds, under laboratory conditions, can apparently inhibit both the oxidation of ferrous to ferric iron by T. ferrooxidans and the weathering of pyritic material by mixed cultures of acid mine drainage micro-organisms. Sodium lauryl sulphate (SLS), an anionic surfactant has proved effective in this respect. Benzoic acid, sorbic acid and SLS at low concentrations, each effectively inhibited bacterial oxidation of ferrous iron in batch cultures of T. ferrooxidans. The rate of chemical oxidation of ferrous iron in low pH, sterile, batch reactors was not substantially affected at the tested concentrations of any of the compounds.

  20. Nitric acid uptake by sulfuric acid solutions under stratospheric conditions - Determination of Henry's Law solubility

    NASA Technical Reports Server (NTRS)

    Reihs, Christa M.; Golden, David M.; Tolbert, Margaret A.

    1990-01-01

    The uptake of nitric acid by sulfuric acid solutions representative of stratospheric particulate at low temperatures was measured to determine the solubility of nitric acid in sulfuric acid solutions as a function of H2SO4 concentration and solution temperature. Solubilities are reported for sulfuric acid solutions ranging from 58 to 87 wt pct H2SO4 over a temperature range from 188 to 240 K, showing that, in general, the solubility of nitric acid increases with decreasing sulfuric acid concentration and with decreasing temperature. The measured solubilities indicate that nitric acid in the global stratosphere will be found predominantly in the gas phase.

  1. Regioselective sulfation of Artemisia sphaerocephala polysaccharide: Solution conformation and antioxidant activities in vitro.

    PubMed

    Wang, Junlong; Yang, Wen; Tang, YinYing; Xu, Qing; Huang, Shengli; Yao, Jian; Zhang, Ji; Lei, Ziqiang

    2016-01-20

    Regioselective modification is an effective approach to synthesize polysaccharides with different structure features and improved properties. In this study, regioselective sulfation of Artemisia sphaerocephala polysaccharide (SRSASP) was prepared by using triphenylchloromethane (TrCl) as protecting precursor. The decrease in fractal dimension (df) values (1.56-2.04) of SRSASP was observed in size-exclusion chromatography combined with multi angle laser light scattering (SEC-MALLS) analysis. Compared to sample substituted at C-6, SRSASP showed a more expanded conformation of random coil, which was attributed to the breakup of hydrogen bonds and elastic contributions. Circular dichroism (CD), methylene blue (MB) and congo red (CR) spectrophotometric method and atomic force microscopy (AFM) results confirmed the conformational transition and stiffness of the chains after sulfation. SRSASP exhibited enhanced antioxidant activities in the DPPH, superoxide and hydroxyl radical scavenging assay. Sulfation at C-2 or C-3 was favorable for the chelation which might prevent the generation of hydroxyl radicals. It concluded that the degree of substitution and substitution position were the factors influencing biological activities of sulfated polysaccharides.

  2. Size distribution of acidic sulfate ions in fine ambient particulate matter and assessment of source region effect

    NASA Astrophysics Data System (ADS)

    Hazi, Y.; Heikkinen, M. S. A.; Cohen, B. S.

    Human exposure studies strongly suggested that the fine fraction of ambient particulate matter (PM) and its associated acidic sulfates are closely correlated with observed adverse health effects. Acidic sulfates are the products of atmospheric sulfur dioxide oxidation and neutralization processes. Few data are available on the amount and size distribution of acidic sulfates within the fine fraction of ambient PM. Knowledge of this distribution will help to understand their toxic mechanisms in the human respiratory tract. The goals of this research were: (1) to measure the size distribution of hydrogen ion, sulfate, and ammonium within the fine fraction of the ambient aerosol in air masses originating from different source regions; and (2) to examine the effect of the source region and the seasons on the sampled PM composition. Six size fractions within the fine ambient PM were collected using a micro-orifice impactor. Results from 30 sampling sessions demonstrated that higher total concentrations of these three ions were observed during the warm months than during the cold months of the year. Size distribution results show that the midpoint diameter of the fraction of particles with the largest fraction of hydrogen, sulfate and ammonium ions was 0.38 μm. Although most of the mass containing hydrogen and sulfate ions was measured in the fraction of particles with 0.38 μm midpoint diameter, the ultrafine fraction (<0.1 μm) was found to be more acidic. Ambient ion concentrations varied between sampling sessions and seasons, but the overall size distribution profiles are similar. Air mass back trajectories were used to identify the source region of the sampled aerosols. No apparent source region effect was observed in terms of the distribution profile of the ions. However, samples collected from air masses that originated from, or passed over, high sulfur dioxide emission areas demonstrated higher concentrations of the different ions.

  3. Sulfation and biological activities of konjac glucomannan.

    PubMed

    Bo, Surina; Muschin, Tegshi; Kanamoto, Taisei; Nakashima, Hideki; Yoshida, Takashi

    2013-05-15

    The sulfation of konjac glucomannan and its anti-HIV and blood anticoagulant activities were investigated. Konjac glucomannan is a polysaccharide occurring naturally in konjac plant tubers and has high molecular weights. Solubility in water is very low, and the aqueous solutions at low concentrations have high viscosity. Before sulfation, hydrolysis by diluted sulfuric acid was carried out to decrease the molecular weights of M¯n=19.2 × 10(4)-0.2 × 10(4). Sulfation with piperidine-N-sulfonic acid or SO3-pyridine complex gave sulfated konjac glucomannans with molecular weights of M¯n=1.0 × 10(4)-0.4 × 10(4) and degrees of sulfation (DS) of 1.3-1.4. It was found that the sulfated konjac glucomannans had potent anti-HIV activity at a 50% effective concentration, (EC50) of 1.2-1.3 μg/ml, which was almost as high as that of an AIDS drug, ddC, whose EC50=3.2 μg/ml, and moderate blood anticoagulant activity, AA=0.8-22.7 units/mg, compared to those of standard sulfated polysaccharides, curdlan (10 units/mg) and dextran (22.7 units/mg) sulfates. Structural analysis of sulfated konjac glucomannans with negatively charged sulfated groups was performed by high resolution NMR, and the interaction between poly-l-lysine with positively charged amino groups as a model compound of proteins and peptides was measured by surface plasmon resonance measurement, suggesting that the sulfated konjac glucomannans had a high binding stability on immobilized poly-l-lysine. The binding of sulfated konjac glucomannan was concentration-dependent, and the biological activity of the sulfated konjac glucomannans may be due to electrostatic interaction between the sulfate and amino groups.

  4. Performance and microbial community dynamics of a sulfate-reducing bioreactor treating coal generated acid mine drainage.

    PubMed

    Burns, Andrew S; Pugh, Charles W; Segid, Yosief T; Behum, Paul T; Lefticariu, Liliana; Bender, Kelly S

    2012-06-01

    The effectiveness of a passive flow sulfate-reducing bioreactor processing acid mine drainage (AMD) generated from an abandoned coal mine in Southern Illinois was evaluated using geochemical and microbial community analysis 10 months post bioreactor construction. The results indicated that the treatment system was successful in both raising the pH of the AMD from 3.09 to 6.56 and in lowering the total iron level by 95.9%. While sulfate levels did decrease by 67.4%, the level post treatment (1153 mg/l) remained above recommended drinking water levels. Stimulation of biological sulfate reduction was indicated by a +2.60‰ increase in δ(34)S content of the remaining sulfate in the water post-treatment. Bacterial community analysis targeting 16S rRNA and dsrAB genes indicated that the pre-treated samples were dominated by bacteria related to iron-oxidizing Betaproteobacteria, while the post-treated water directly from the reactor outflow was dominated by sequences related to sulfur-oxidizing Epsilonproteobacteria and complex carbon degrading Bacteroidetes and Firmicutes phylums. Analysis of the post-treated water, prior to environmental release, revealed that the community shifted back to predominantly iron-oxidizing Betaproteobacteria. DsrA analysis implied limited diversity in the sulfate-reducing population present in both the bioreactor outflow and oxidation pond samples. These results support the use of passive flow bioreactors to lower the acidity, metal, and sulfate levels present in the AMD at the Tab-Simco mine, but suggest modifications of the system are necessary to both stimulate sulfate-reducing bacteria and inhibit sulfur-oxidizing bacteria.

  5. Development of a Combined Solution Formulation of Atropine Sulfate and Obidoxime Chloride for Autoinjector and Evaluation of Its Stability

    PubMed Central

    Ettehadi, Hossein Ali; Ghalandari, Rouhollah; Shafaati, Alireza; Foroutan, Seyed Mohsen

    2013-01-01

    Atropine (AT) and oximes, alone or in combination, have been proven greatly valuable therapeutics in the treatment of organophosphates intoxications. An injectable mixture of AT and obidoxime (OB) was formulated for the administration by automatic self-injector. The aqueous single dose solution contained 275 mg obidoxime chloride and 2.5 mg atropine sulfate per 1 mL (220 mg and 2 mg per 0.8 effective dose, respectively). The final solution was sterilized by filtration through a 0.22 μm pore size filter. This more concentrated solution allowed to use a smaller size and lighter weight cartridge. Quality control tests, including assay of the two major compounds were performed separately, using reversed-phase HPLC methods. Besides, the stability test was carried out according to ICH guideline for the accelerated test. The obtained results showed that the proposed formulation is stable over a period of 2 years after preparation. PMID:24250669

  6. A comparative study of the sulfation of bile acids and a bile alcohol by the Zebra danio (Danio rerio) and human cytosolic sulfotransferases (SULTs)

    PubMed Central

    Kurogi, Katsuhisa; Krasowski, Matthew D.; Injeti, Elisha; Liu, Ming-Yih; Williams, Frederick E.; Sakakibara, Yoichi; Suiko, Masahito; Liu, Ming-Cheh

    2012-01-01

    The current study was designed to examine the sulfation of bile acids and bile alcohols by the Zebra danio (Danio rerio) SULTs in comparison with human SULTs. A systematic analysis using the fifteen Zebra danio SULTs revealed that SULT3 ST2 and SULT3 ST3 were the major bile acid/alcohol-sulfating SULTs. Among the eleven human SULTs, only SULT2A1 was found to be capable of sulfating bile acids and bile alcohols. To further investigate the sulfation of bile acids and bile alcohols by the two Zebra danio SULT3 STs and the human SULT2A1, pH-dependence and kinetics of the sulfation of bile acids/alcohols were analyzed. pH-dependence experiments showed that the mechanisms underlying substrate recognition for the sulfation of lithocholic acid (a bile acid) and 5α-petromyzonol (a bile alcohol) differed between the human SULT2A1 and the Zebra danio SULT3 ST2 and ST3. Kinetic analysis indicated that both the two Zebra danio SULT3 STs preferred petromyzonol as substrate compared to bile acids. In contrast, the human SULT2A1 was more catalytically efficient toward lithocholic acid than petromyzonol. Collectively, the results imply that the Zebra danio and human SULTs have evolved to serve for the sulfation of, respectively, bile alcohols and bile acids, matching the cholanoid profile in these two vertebrate species. PMID:21839837

  7. Recovery of water and acid from leach solutions using direct contact membrane distillation.

    PubMed

    Kesieme, Uchenna K; Milne, Nicholas; Cheng, Chu Yong; Aral, Hal; Duke, Mikel

    2014-01-01

    This paper describes for the first time the use of direct contact membrane distillation (DCMD) for acid and water recovery from a real leach solution generated by a hydrometallurgical plant. The leach solutions considered contained H2SO4 or HCl. In all tests the temperature of the feed solution was kept at 60 °C. The test work showed that fluxes were within the range of 18-33 kg/m(2)/h and 15-35 kg/m(2)/h for the H2SO4 and HCl systems, respectively. In the H2SO4 leach system, the final concentration of free acid in the sample solution increased on the concentrate side of the DCMD system from 1.04 M up to 4.60 M. The sulfate separation efficiency was over 99.9% and overall water recovery exceeded 80%. In the HCl leach system, HCl vapour passed through the membrane from the feed side to the permeate. The concentration of HCl captured in the permeate was about 1.10 M leaving behind only 0.41 M in the feed from the initial concentration of 2.13 M. In all the experiments, salt rejection was >99.9%. DCMD is clearly viable for high recovery of high quality water and concentrated H2SO4 from spent sulfuric acid leach solution where solvent extraction could then be applied to recover the sulfuric acid and metals. While HCl can be recovered for reuse using only DCMD.

  8. Extractive separation and determination of arsenic at different valences in industrial solutions and sulfuric acid production waste waters

    SciTech Connect

    Minasyan, K.V.; Vrtanesyan, S.G.; Badalyan, M.A.

    1986-12-01

    Wash towers of sulfuric acid production divisions of non-ferrous metallurgy plants contain sulfated solutions and waste waters with arsenic contents over a wide range of concentrations (1-20 g/liter). These solutions also contain large amounts of iron, copper, zinc, selenium, tellurium, and other impurities. Monitoring arsenic removal from the solutions requires rapid and accurate methods of determining not only the total arsenic content but also its valence state. In this paper, the authors report the quantitative extractive separation of arsenic(III) from sulfuric acid solutions with toluene (or benzene) in the presence of chlorides. The technique is intended to be a preliminary step in developing a method for separately determining tri- and pentavalent arsenic in complex sulfuric acid solutions.

  9. Effectiveness of 5-Pyrrolidone-2-carboxylic Acid and Copper Sulfate Pentahydrate Association against Drug Resistant Staphylococcus Strains.

    PubMed

    Governa, Paolo; Miraldi, Elisabetta; De Fina, Gianna; Biagi, Marco

    2016-04-01

    Bacterial resistance is an ongoing challenge for pharmacotherapy and pharmaceutical chemistry. Staphylococcus aureus is the bacterial species which makes it most difficult to treat skin and soft tissue infections and it is seen in thousands of hospitalization cases each year. Severe but often underrated infectious diseases, such as complicated nasal infections, are primarily caused by MRSA and S. epidermidis too. With the aim of studying new drugs with antimicrobial activity and effectiveness on drug resistant Staphylococcus strains, our attention in this study was drawn on the activity of a new association between two natural products: 5-pyrrolidone-2-carboxylic acid (PCA), naturally produced by certain Lactobacillus species, and copper sulfate pentahydrate (CS). The antimicrobial susceptibility test was conducted taking into account 12 different Staphylococcus strains, comprising 6 clinical isolates and 6 resistant strains. PCA 4%, w/w, and CS 0.002%, w/w, association in distilled water solution was found to have bactericidal activity against all tested strains. Antimicrobial kinetics highlighted that PCA 4%, w/w, and CS 0.002% association could reduce by 5 log10 viable bacterial counts of MRSA and oxacillin resistant S. epidennidis in less than 5 and 3 minutes respectively. Microscopic investigations suggest a cell wall targeting mechanism of action. Being very safe and highly tolerated, the natural product PCA and CS association proved to be a promising antimicrobial agent to treat Staphylococcus related infections.

  10. Porewater geochemistry of inland Acid sulfate soils with sulfuric horizons following postdrought reflooding with freshwater.

    PubMed

    Creeper, Nathan L; Shand, Paul; Hicks, Warren; Fitzpatrick, Rob W

    2015-05-01

    Following the break of a severe drought in the Murray-Darling Basin, rising water levels restored subaqueous conditions to dried inland acid sulfate soils with sulfuric horizons (pH <3.5). Equilibrium dialysis membrane samplers were used to investigate in situ changes to soil acidity and abundance of metals and metalloids following the first 24 mo of restored subaqueous conditions. The rewetted sulfuric horizons remained severely acidified (pH ∼4) or had retained acidity with jarosite visibly present after 5 mo of continuous subaqueous conditions. A further 19 mo of subaqueous conditions resulted in only small additional increases in pH (∼0.5-1 pH units), with the largest increases occurring within the uppermost 10 cm of the soil profile. Substantial decreases in concentrations of some metal(loid)s were observed with time most likely owing to lower solubility and sorption as a consequence of the increase in pH. In deeper parts of the profiles, porewater remained strongly buffered at low pH values (pH <4.5) and experienced little progression toward anoxic circumneutral pH conditions over the 24 mo of subaqueous conditions. It is proposed that low pH conditions inhibited the activity of SO-reducing bacteria and, in turn, the in situ generation of alkalinity through pyrite production. The limited supply of alkalinity in freshwater systems and the initial highly buffered low pH conditions were also thought to be slowing recovery. The timescales involved for a sulfuric horizon rewetted by a freshwater body to recover from acidic conditions could therefore be in the order of several years.

  11. Preparation and application of zirconium sulfate supported on SAPO-34 molecular sieve as solid acid catalyst for esterification

    SciTech Connect

    Xu, Dongyan Ma, Hong; Cheng, Fei

    2014-05-01

    Graphical abstract: - Highlights: • SAPO-34 supported zirconium sulfate solid acid catalyst was prepared. • Esterification of acetic acid with ethanol can be catalyzed by ZS/SAPO-34. • The hydration of ZS is vital to the acidic property and catalytic performance. • The ZS/SAPO-34 catalyst treated at 200 °C shows good reusability. - Abstract: Zirconium sulfate (ZS) was supported on SAPO-34 molecular sieve by using an incipient wetness impregnation method with zirconium sulfate as the precursor. The as-prepared catalysts were used as solid acid catalyst for esterification reaction of acetic acid with ethanol. The influence of calcination temperature on the acidic property, catalytic activity, and reusability of ZS/SAPO-34 catalysts were mainly investigated. FT-IR, SEM, EDS and TG analysis have been carried out to demonstrate the characteristics of ZS/SAPO-34 catalysts. It was found that the 30 wt%ZS/SAPO-34 catalysts display the property of superacid irrespective of calcination temperature. The ZS/SAPO-34 catalyst treated at 200 °C can enhance the interaction between the supported ZS and SAPO-34 and keep the catalyst remaining substantially active after several reaction cycles. However, further increasing calcination temperature will cause the transfer of ZS from hydrate to anhydrous phase, and thus the decrease of activity.

  12. Laboratory simulations of acid-sulfate weathering under volcanic hydrothermal conditions: Implications for early Mars

    PubMed Central

    Marcucci, Emma C; Hynek, Brian M

    2014-01-01

    We have completed laboratory experiments and thermochemical equilibrium models to investigate secondary mineral formation under conditions akin to volcanic, hydrothermal acid-sulfate weathering systems. Our research used the basaltic mineralogy at Cerro Negro Volcano, Nicaragua, characterized by plagioclase, pyroxene, olivine, and volcanic glass. These individual minerals and whole-rock field samples were reacted in the laboratory with 1 molal sulfuric acid at varying temperatures (65, 150, and 200°C), fluid:rock weight ratios (1:1, 4:1, and 10:1), and durations (1–60 days). Thermochemical equilibrium models were developed using Geochemist's Workbench. To understand the reaction products and fluids, we employed scanning electron microscopy/energy dispersive spectroscopy, X-ray diffraction, and inductively coupled plasma-atomic emission spectroscopy. The results of our experiments and models yielded major alteration minerals that include anhydrite, natroalunite, minor iron oxide, and amorphous Al-Si gel. We found that variations in experimental parameters did not drastically change the suite of minerals produced; instead, abundance, size, and crystallographic shape changed. Our results also suggest that it is essential to separate phases formed during experiments from those formed during fluid evaporation to fully understand the reaction processes. Our laboratory reacted and model predicted products are consistent with the mineralogy observed at places on Mars. However, our results indicate that determination of the formation conditions requires microscopic imagery and regional context, as well as a thorough understanding of contributions from both experiment precipitation and fluid evaporation minerals. PMID:26213665

  13. Laboratory simulations of acid-sulfate weathering under volcanic hydrothermal conditions: Implications for early Mars.

    PubMed

    Marcucci, Emma C; Hynek, Brian M

    2014-03-01

    We have completed laboratory experiments and thermochemical equilibrium models to investigate secondary mineral formation under conditions akin to volcanic, hydrothermal acid-sulfate weathering systems. Our research used the basaltic mineralogy at Cerro Negro Volcano, Nicaragua, characterized by plagioclase, pyroxene, olivine, and volcanic glass. These individual minerals and whole-rock field samples were reacted in the laboratory with 1 molal sulfuric acid at varying temperatures (65, 150, and 200°C), fluid:rock weight ratios (1:1, 4:1, and 10:1), and durations (1-60 days). Thermochemical equilibrium models were developed using Geochemist's Workbench. To understand the reaction products and fluids, we employed scanning electron microscopy/energy dispersive spectroscopy, X-ray diffraction, and inductively coupled plasma-atomic emission spectroscopy. The results of our experiments and models yielded major alteration minerals that include anhydrite, natroalunite, minor iron oxide, and amorphous Al-Si gel. We found that variations in experimental parameters did not drastically change the suite of minerals produced; instead, abundance, size, and crystallographic shape changed. Our results also suggest that it is essential to separate phases formed during experiments from those formed during fluid evaporation to fully understand the reaction processes. Our laboratory reacted and model predicted products are consistent with the mineralogy observed at places on Mars. However, our results indicate that determination of the formation conditions requires microscopic imagery and regional context, as well as a thorough understanding of contributions from both experiment precipitation and fluid evaporation minerals.

  14. Laboratory simulations of acid-sulfate weathering under volcanic hydrothermal conditions: Implications for early Mars

    NASA Astrophysics Data System (ADS)

    Marcucci, Emma C.; Hynek, Brian M.

    2014-03-01

    We have completed laboratory experiments and thermochemical equilibrium models to investigate secondary mineral formation under conditions akin to volcanic, hydrothermal acid-sulfate weathering systems. Our research used the basaltic mineralogy at Cerro Negro Volcano, Nicaragua, characterized by plagioclase, pyroxene, olivine, and volcanic glass. These individual minerals and whole-rock field samples were reacted in the laboratory with 1 molal sulfuric acid at varying temperatures (65, 150, and 200°C), fluid:rock weight ratios (1:1, 4:1, and 10:1), and durations (1-60 days). Thermochemical equilibrium models were developed using Geochemist's Workbench. To understand the reaction products and fluids, we employed scanning electron microscopy/energy dispersive spectroscopy, X-ray diffraction, and inductively coupled plasma-atomic emission spectroscopy. The results of our experiments and models yielded major alteration minerals that include anhydrite, natroalunite, minor iron oxide, and amorphous Al-Si gel. We found that variations in experimental parameters did not drastically change the suite of minerals produced; instead, abundance, size, and crystallographic shape changed. Our results also suggest that it is essential to separate phases formed during experiments from those formed during fluid evaporation to fully understand the reaction processes. Our laboratory reacted and model predicted products are consistent with the mineralogy observed at places on Mars. However, our results indicate that determination of the formation conditions requires microscopic imagery and regional context, as well as a thorough understanding of contributions from both experiment precipitation and fluid evaporation minerals.

  15. Contemporaneous deposition of phyllosilicates and sulfates: Using Australian acidic saline lake deposits to describe geochemical variability on Mars

    USGS Publications Warehouse

    Baldridge, A.M.; Hook, S.J.; Crowley, J.K.; Marion, G.M.; Kargel, J.S.; Michalski, J.L.; Thomson, B.J.; de Souza, Filho C.R.; Bridges, N.T.; Brown, A.J.

    2009-01-01

    Studies of the origin of the Martian sulfate and phyllosilicate deposits have led to the hypothesis that there was a marked, global-scale change in the Mars environment from circum-neutral pH aqueous alteration in the Noachian to an acidic evaporitic system in the late Noachian to Hesperian. However, terrestrial studies suggest that two different geochemical systems need not be invoked to explain such geochemical variation.Western Australian acidic playa lakes have large pH differences separated vertically and laterally by only a few tens of meters, demonstrating how highly variable chemistries can coexist over short distances in natural environments. We suggest diverse and variable Martian aqueous environments where the coetaneous formation of phyllosilicates and sulfates at the Australian sites are analogs for regions where phyllosilicates and sulfates coexist on Mars. In these systems, Fe and alkali earth phyllosilicates represent deep facies associated with upwelling neutral to alkaline groundwater, whereas aluminous phyllosilicates and sulfates represent near-surface evaporitic facies formed from more acidic brines. Copyright 2009 by the American Geophysical Union.

  16. Contemporaneous deposition of phyllosilicates and sulfates: Using Australian acidic saline lake deposits to describe geochemical variability on Mars

    NASA Astrophysics Data System (ADS)

    Baldridge, A. M.; Hook, S. J.; Crowley, J. K.; Marion, G. M.; Kargel, J. S.; Michalski, J. L.; Thomson, B. J.; de Souza Filho, C. R.; Bridges, N. T.; Brown, A. J.

    2009-10-01

    Studies of the origin of the Martian sulfate and phyllosilicate deposits have led to the hypothesis that there was a marked, global-scale change in the Mars environment from circum-neutral pH aqueous alteration in the Noachian to an acidic evaporitic system in the late Noachian to Hesperian. However, terrestrial studies suggest that two different geochemical systems need not be invoked to explain such geochemical variation. Western Australian acidic playa lakes have large pH differences separated vertically and laterally by only a few tens of meters, demonstrating how highly variable chemistries can coexist over short distances in natural environments. We suggest diverse and variable Martian aqueous environments where the coetaneous formation of phyllosilicates and sulfates at the Australian sites are analogs for regions where phyllosilicates and sulfates coexist on Mars. In these systems, Fe and alkali earth phyllosilicates represent deep facies associated with upwelling neutral to alkaline groundwater, whereas aluminous phyllosilicates and sulfates represent near-surface evaporitic facies formed from more acidic brines.

  17. Evaluating enhanced sulfate reduction and optimized volatile fatty acids (VFA) composition in anaerobic reactor by Fe (III) addition.

    PubMed

    Liu, Yiwen; Zhang, Yaobin; Ni, Bing-Jie

    2015-02-17

    Anaerobic reactors with ferric iron addition have been experimentally demonstrated to be able to simultaneously improve sulfate reduction and organic matter degradation during sulfate-containing wastewater treatment. In this work, a mathematical model is developed to evaluate the impact of ferric iron addition on sulfate reduction and organic carbon removal as well as the volatile fatty acids (VFA) composition in anaerobic reactor. The model is successfully calibrated and validated using independent long-term experimental data sets from the anaerobic reactor with Fe (III) addition under different operational conditions. The model satisfactorily describes the sulfate reduction, organic carbon removal and VFA production. Results show Fe (III) addition induces the microbial reduction of Fe (III) by iron reducing bacteria (IRB), which significantly enhances sulfate reduction by sulfate reducing bacteria (SRB) and subsequently changes the VFA composition to acetate-dominating effluent. Simultaneously, the produced Fe (II) from IRB can alleviate the inhibition of undissociated H2S on microorganisms through iron sulfide precipitation, resulting in further improvement of the performance. In addition, the enhancement on reactor performance by Fe (III) is found to be more significantly favored at relatively low organic carbon/SO4(2-) ratio (e.g., 1.0) than at high organic carbon/SO4(2-) ratio (e.g., 4.5). The Fe (III)-based process of this work can be easily integrated with a commonly used strategy for phosphorus recovery, with the produced sulfide being recovered and then deposited into conventional chemical phosphorus removal sludge (FePO4) to achieve FeS precipitation for phosphorus recovery while the required Fe (III) being acquired from the waste ferric sludge of drinking water treatment process, to enable maximum resource recovery/reuse while achieving high-rate sulfate removal.

  18. Electrode kinetics at a platinum anode in chloroacetic acid solutions

    SciTech Connect

    Lotvin, B.M.; Vasil'ev, Yu.B.

    1987-02-01

    It was shown by direct comparison of kinetic and adsorption data that at platinum in solutions of mono- and trichloroacetic acid, the anodic processes are entirely analogous in character to the processes occurring in acetate solutions. The lack of Kolbe electrosynthesis products in the electrolysis of chloroacetic acids is to the special reaction features of the secondary chloroalkyl radicals.

  19. Effect of cyclic redox oscillations on water quality in freshwater acid sulfate soil wetlands.

    PubMed

    Karimian, Niloofar; Johnston, Scott G; Burton, Edward D

    2017-03-01

    Restoration of acid sulfate soil (ASS) wetlands by freshwater re-flooding can lead to the reformation of various Fe(II) and reduced inorganic sulfur (RIS) species in surface soil layers. However, in many locations, wetland water levels undergo large seasonal fluctuations that drive extreme redox oscillations. Newly formed RIS species [e.g. greigite, mackinawite, nano-pyrite and S(0)] and Fe(II) are vulnerable to rapid oxidation during dry periods and may generate substantial acidity. Rainfall following a dry period may then mobilise acidity and metal cations in surface waters prior to eventual recovery in pH by re-establishment of reducing conditions. We explore this dry-wet transition by subjecting soil samples from two freshwater re-flooded ASS wetlands to oxidative incubation for up to 130days followed by re-flooding simulation for 84days. During very early stages of re-flooding (up to 7days) there was an initial pulse-release of acidity, and trace metals/metalloids (Al, Mn, Zn and As). This was followed by a rapid reversion to anoxia, and Fe(III) and SO4 reducing conditions which generated alkalinity, ameliorated acidity and sequestered Fe, S, Zn, Mn and As. Field-observations of surface water quality in an ASS wetland at a sub-catchment scale also confirms re-establishment of SO4 reducing conditions and recovery of pH within ~4-8weeks of re-flooding after dry periods. These observations suggest that retaining surface water in ASS wetlands for ~8weeks after a dry-wet transition will allow sufficient time for alkalinity producing reductive processes to ameliorate most surface water acidity. Although management of freshwater re-flooded ASS wetlands in a highly dynamic climate will remain challenging over the long term and the post-remediation effectiveness of the method depends on initial soil characteristics, knowledge of the timing of redox oscillations and the associated changes in water geochemistry can be helpful for mitigating the risks to downstream

  20. Rapid identification of triterpenoid sulfates and hydroxy fatty acids including two new constituents from Tydemania expeditionis by LC-MS

    PubMed Central

    Zhang, Jian-Long; Kubanek, Julia; Hay, Mark E.; Aalbersberg, William; Ye, Wen-Cai; Jiang, Ren-Wang

    2011-01-01

    Tydemania expeditionis Weber-van Bosse (Udoteaceae) is a weakly calcified green alga. In the present paper, liquid chromatography coupled with photodiode array detection and electrospray mass spectrometry was developed to identify the fingerprint components. A total of four triterpenoid sulfates and three hydroxy fatty acids in the ethyl acetate fraction of the crude extract were structurally characterized on the basis of retention time, online UV spectrum and mass fragmentation pattern. Furthermore, detailed LC-MS analysis revealed two new hydroxy fatty acids, which were then prepared and characterized by extensive NMR analyses. The proposed method provides a scientific and technical platform for the rapid identification of triterpenoid sulfates and hydroxy fatty acids in similar marine algae and terrestrial plants. PMID:21915955

  1. Exchangeable and secondary mineral reactive pools of aluminium in coastal lowland acid sulfate soils.

    PubMed

    Yvanes-Giuliani, Yliane A M; Waite, T David; Collins, Richard N

    2014-07-01

    The use of coastal floodplain sulfidic sediments for agricultural activities has resulted in the environmental degradation of many areas worldwide. The generation of acidity and transport of aluminium (Al) and other metals to adjacent aquatic systems are the main causes of adverse effects. Here, a five-step sequential extraction procedure (SEP) was applied to 30 coastal lowland acid sulfate soils (CLASS) from north-eastern New South Wales, Australia. This enabled quantification of the proportion of aluminium present in 'water-soluble', 'exchangeable', 'organically-complexed', 'reducible iron(III) (oxyhydr)oxide/hydroxysulfate-incorporated' and 'amorphous Al mineral' fractions. The first three extractions represented an average of 5% of 'aqua regia' extractable Al and their cumulative concentrations were extremely high, reaching up to 4000 mg·kg(-1). Comparison of Al concentrations in the final two extractions indicated that 'amorphous Al minerals' are quantitatively a much more important sink for the removal of aqueous Al derived from the acidic weathering of these soils than reducible Fe(III) minerals. Correlations were observed between soil pH, dissolved and total organic carbon (DOC and TOC) and Al concentrations in organic carbon-rich CLASS soil horizons. These results suggest that complexation of Al by dissolved organic matter significantly increases soluble Al concentrations at pH values >5.0. As such, present land management practices would benefit with redefinition of an 'optimal' soil from pH ≥5.5 to ~4.8 for the preservation of aquatic environments adjacent to organic-rich CLASS where Al is the sole or principle inorganic contaminant of concern. Furthermore, it was observed that currently-accepted standard procedures (i.e. 1 M KCl extraction) to measure exchangeable Al concentrations in these types of soils severely underestimate exchangeable Al and a more accurate representation may be obtained through the use of 0.2 M CuCl2.

  2. Isotopic constraints on the role of hypohalous acids in sulfate aerosol formation in the remote marine boundary layer

    NASA Astrophysics Data System (ADS)

    Chen, Qianjie; Geng, Lei; Schmidt, Johan A.; Xie, Zhouqing; Kang, Hui; Dachs, Jordi; Cole-Dai, Jihong; Schauer, Andrew J.; Camp, Madeline G.; Alexander, Becky

    2016-09-01

    Sulfate is an important component of global atmospheric aerosol, and has partially compensated for greenhouse gas-induced warming during the industrial period. The magnitude of direct and indirect radiative forcing of aerosols since preindustrial times is a large uncertainty in climate models, which has been attributed largely to uncertainties in the preindustrial environment. Here, we report observations of the oxygen isotopic composition (Δ17O) of sulfate aerosol collected in the remote marine boundary layer (MBL) in spring and summer in order to evaluate sulfate production mechanisms in pristine-like environments. Model-aided analysis of the observations suggests that 33-50 % of sulfate in the MBL is formed via oxidation by hypohalous acids (HOX = HOBr + HOCl), a production mechanism typically excluded in large-scale models due to uncertainties in the reaction rates, which are due mainly to uncertainties in reactive halogen concentrations. Based on the estimated fraction of sulfate formed via HOX oxidation, we further estimate that daily-averaged HOX mixing ratios on the order of 0.01-0.1 parts per trillion (ppt = pmol/mol) in the remote MBL during spring and summer are sufficient to explain the observations.

  3. Nickel recovery from electronic waste II electrodeposition of Ni and Ni-Fe alloys from diluted sulfate solutions.

    PubMed

    Robotin, B; Ispas, A; Coman, V; Bund, A; Ilea, P

    2013-11-01

    This study focuses on the electrodeposition of Ni and Ni-Fe alloys from synthetic solutions similar to those obtained by the dissolution of electron gun (an electrical component of cathode ray tubes) waste. The influence of various parameters (pH, electrolyte composition, Ni(2+)/Fe(2+) ratio, current density) on the electrodeposition process was investigated. Scanning electron microscopy (SEM) and X-ray fluorescence analysis (XRFA) were used to provide information about the obtained deposits' thickness, morphology, and elemental composition. By controlling the experimental parameters, the composition of the Ni-Fe alloys can be tailored towards specific applications. Complementarily, the differences in the nucleation mechanisms for Ni, Fe and Ni-Fe deposition from sulfate solutions have been evaluated and discussed using cyclic voltammetry and potential step chronoamperometry. The obtained results suggest a progressive nucleation mechanism for Ni, while for Fe and Ni-Fe, the obtained data points are best fitted to an instantaneous nucleation model.

  4. Assessment of the Effects Exerted by Acid and Alkaline Solutions on Bone: Is Chemistry the Answer?

    PubMed

    Amadasi, Alberto; Camici, Arianna; Porta, Davide; Cucca, Lucia; Merli, Daniele; Milanese, Chiara; Profumo, Antonella; Rassifi, Nabila; Cattaneo, Cristina

    2017-02-01

    The treatment of corpses with extremely acid or basic liquids is sometimes performed in criminal contexts. A thorough characterization by chemical analysis may provide further help to macroscopic and microscopic analysis; 63 porcine bone samples were treated with solutions at different pH (1-14) for immersion periods up to 70 days, as well as in extremely acidic sulfuric acid solutions (9 M/18 M) and extremely basic sodium hydroxide. Inductively coupled optical emission spectrometry (ICP-OES)/plasma mass spectrometry (ICP-MS), Fourier transform infrared spectroscopy (FT-IR), energy dispersive X-ray analysis (EDX), X-ray powder diffraction (XRPD), and scanning electron microscopy (SEM) showed that only the sulfuric acid solution 18 M was able to completely dissolve the sample. In addition, chemical analysis allowed to recognize the contact between bone and substances. Hydrated calcium sulfate arose from extreme pH. The possibility of detecting the presence of human material within the residual solution was demonstrated, especially with FT-IR, ICP-OES, and EDX.

  5. Gamma ray-induced synthesis of hyaluronic acid/chondroitin sulfate-based hydrogels for biomedical applications

    NASA Astrophysics Data System (ADS)

    Zhao, Linlin; Gwon, Hui-Jeong; Lim, Youn-Mook; Nho, Young-Chang; Kim, So Yeon

    2015-01-01

    Hyaluronic acid (HA)/chondroitin sulfate (CS)/poly(acrylic acid) (PAAc) hydrogel systems were synthesized by gamma-ray irradiation without the use of additional initiators or crosslinking agents to achieve a biocompatible hydrogel system for skin tissue engineering. HA and CS derivatives with polymerizable residues were synthesized. Then, the hydrogels composed of glycosaminoglycans, HA, CS, and a synthetic ionic polymer, PAAc, were prepared using gamma-ray irradiation through simultaneous free radical copolymerization and crosslinking. The physicochemical properties of the HA/CS/PAAc hydrogels having various compositions were investigated to evaluate their feasibility as artificial skin substitutes. The gel fractions of the HA/CS/PAAc hydrogels increased in absorbed doses up to 15 kGy, and they exhibited 91-93% gel fractions under 15 kGy radiation. All of the HA/CS/PAAc hydrogels exhibited relatively high water contents of over 90% and reached an equilibrium swelling state within 24 h. The enzymatic degradation kinetics of the HA/CS/PAAc hydrogels depended on both the concentration of the hyaluronidase solution and the ratio of HA/CS/PAAc. The in vitro drug release profiles of the HA/CS/PAAc hydrogels were significantly influenced by the interaction between the ionic groups in the hydrogels and the ionic drug molecules as well as the swelling of the hydrogels. From the cytotoxicity results of human keratinocyte (HaCaT) cells cultured with extracts of the HA/CS/PAAc hydrogels, all of the HA/CS/PAAc hydrogel samples tested showed relatively high cell viabilities of more than 82%, and did not induce any significant adverse effects on cell viability.

  6. Citric Acid-Modified Fenton's Reaction for the Oxidation of Chlorinated Ethylenes in Soil Solution Systems

    SciTech Connect

    Seol, Yongkoo; Javandel, Iraj

    2008-03-15

    Fenton's reagent, a solution of hydrogen peroxide and ferrous iron catalyst, is used for an in-situ chemical oxidation of organic contaminants. Sulfuric acid is commonly used to create an acidic condition needed for catalytic oxidation. Fenton's reaction often involves pressure buildup and precipitation of reaction products, which can cause safety hazards and diminish efficiency. We selected citric acid, a food-grade substance, as an acidifying agent to evaluate its efficiencies for organic contaminant removal in Fenton's reaction, and examined the impacts of using citric acid on the unwanted reaction products. A series of batch and column experiments were performed with varying H{sub 2}O{sub 2} concentrations to decompose selected chlorinated ethylenes. Either dissolved iron from soil or iron sulfate salt was added to provide the iron catalyst in the batch tests. Batch experiments revealed that both citric and sulfuric acid systems achieved over 90% contaminant removal rates, and the presence of iron catalyst was essential for effective decontamination. Batch tests with citric acid showed no signs of pressure accumulation and solid precipitations, however the results suggested that an excessive usage of H{sub 2}O{sub 2} relative to iron catalysts (Fe{sup 2+}/H{sub 2}O{sub 2} < 1/330) would result in lowering the efficiency of contaminant removal by iron chelations in the citric acid system. Column tests confirmed that citric acid could provide suitable acidic conditions to achieve higher than 55% contaminant removal rates.

  7. Sulfate adsorption in Michigan forest soils

    SciTech Connect

    MacDonald, N.W.

    1987-01-01

    The occurrence of acidic atmospheric deposition raised concerns over adverse cation leaching effects on Michigan forest soils with low cation exchange capacities. Leaching effects of acid deposition depend on mobility of sulfate in the soil. Little was known, however, concerning the ability of these soils to adsorb sulfate. The objectives of this study were to determine the ability of representative Michigan forest soils to adsorb sulfate, to relate sulfate adsorption to soil properties, and to develop equations to predict sulfate adsorption in similar forest soils. Frigid zone soil series studied were Grayling (Typic Udipsamments), Rubicon (Entic Haplorthods), Kalkaska (Typic Haplorthods), and Montcalm (Eutric Glossoboralfs). Mesic zone series studied were Spinks (Psammentic Hapludals) and Oshtemo (Typic Hapludalfs). Six randomly located pedons of each series were sampled. Sulfate adsorption was determined by shaking 10 gram soil samples for 24 hours in 50 mL 0.01 M CaCl/sub 2/ solution containing 10 mg SO/sub 4/-S L/sup -1/. Solution filtrates were turbidimetrically analyzed for SO/sub 4/-S and adsorption was calculated from reduction in SO/sub 4/-S concentration. Bw, Bs, and Bh horizons of frigid zone soils and E and Bt horizons of mesic zone soils had the highest sulfate adsorbing abilities. No significant differences were found between series in total sulfate adsorptive capacity.

  8. Small-angle neutron scattering study of the structure of mixed micellar solutions based on heptaethylene glycol monotetradecyl ether and cesium dodecyl sulfate

    SciTech Connect

    Rajewska, A.; Medrzycka, K.; Hallmann, E.; Soloviov, D. V.

    2016-01-15

    The micellization in mixed aqueous systems based on a nonionic surfactant, heptaethylene glycol monotetradecyl ether (C{sub 14}E{sub 7}), and an anionic surfactant, cesium dodecyl sulfate, has been investigated by small-angle neutron scattering. Preliminary data on the behavior of the C{sub 14}E{sub 7} aqueous solutions (with three concentrations, 0.17, 0.5, and 1%) mixed with a small amount of anionic surfactant, cesium dodecyl sulfate, are reported.

  9. Process for the recovery of strontium from acid solutions

    DOEpatents

    Horwitz, E. Philip; Dietz, Mark L.

    1992-01-01

    The invention is a process for selectively extracting strontium and technetium values from aqueous nitric acid waste solutions containing these and other fission product values. The extractant is a macrocyclic polyether in a diluent which is insoluble in water, but which will itself dissolve a small amount of water. The process will extract strontium and technetium values from nitric acid solutions which are up to 6 molar in nitric acid.

  10. Process for the recovery of strontium from acid solutions

    DOEpatents

    Horwitz, E.P.; Dietz, M.L.

    1992-03-31

    The invention is a process for selectively extracting strontium and technetium values from aqueous nitric acid waste solutions containing these and other fission product values. The extractant is a macrocyclic polyether in a diluent which is insoluble in water, but which will itself dissolve a small amount of water. The process will extract strontium and technetium values from nitric acid solutions which are up to 6 molar in nitric acid. 5 figs.

  11. Absorption, fluorescence, and acid-base equilibria of rhodamines in micellar media of sodium dodecyl sulfate

    NASA Astrophysics Data System (ADS)

    Obukhova, Elena N.; Mchedlov-Petrossyan, Nikolay O.; Vodolazkaya, Natalya A.; Patsenker, Leonid D.; Doroshenko, Andrey O.; Marynin, Andriy I.; Krasovitskii, Boris M.

    2017-01-01

    Rhodamine dyes are widely used as molecular probes in different fields of science. The aim of this paper was to ascertain to what extent the structural peculiarities of the compounds influence their absorption, emission, and acid-base properties under unified conditions. The acid-base dissociation (HR+ ⇄ R + H+) of a series of rhodamine dyes was studied in sodium n-dodecylsulfate micellar solutions. In this media, the form R exists as a zwitterion R±. The indices of apparent ionization constants of fifteen rhodamine cations HR+ with different substituents in the xanthene moiety vary within the range of pKaapp = 5.04 to 5.53. The distinct dependence of emission of rhodamines bound to micelles on pH of bulk water opens the possibility of using them as fluorescent interfacial acid-base indicators.

  12. Akaganéite (β-FeOOH) precipitation in inland acid sulfate soils of south-western New South Wales (NSW), Australia

    NASA Astrophysics Data System (ADS)

    Bibi, Irshad; Singh, Balwant; Silvester, Ewen

    2011-11-01

    The prevalence of sulphidic sediments in inland wetlands has been only recently recognized in many parts of the world, including Australia. The exposure of sulphidic sediments in these wetlands due to natural and human induced drying events has resulted in the oxidation of iron sulfide minerals, the formation of secondary iron minerals characteristic of acid sulfate soils and the release of highly acidic solutions. The objective of this study was to determine the mineralogy and morphology of sediments collected from the oxidized surface horizon (0-5 cm) of an inland acid sulfate soil located in south-western New South Wales (NSW), Australia. Random powder X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning transmission electron microscopy combined with energy dispersive X-ray spectroscopy (STEM-EDS) techniques were used to characterize the minerals present in these sediments. Akaganéite was identified as the major mineral phase in the sediments; K-jarosite was also determined in small amounts in some sediments. The XRD patterns of sequentially washed (E-pure® water-0.01 M HCl-0.01 M EDTA) sediment samples showed all akaganéite peaks; the Rietveld refinement of these patterns also revealed a predominance of akaganéite. The chemical analyses of the original and washed sediments using STEM-EDS clearly showed the presence of akaganéite as a pure mineral phase with an average Fe/Cl mole ratio of 6.7 and a structural formula of Fe 8O 8(OH) 6.8(Cl) 1.2. These findings show that the extreme saline-acidic solutions (pH ˜ 2, EC = 216 dS/m) at the Bottle Bend lagoon provide ideal conditions for the crystallization of this rarely forming mineral.

  13. Tough and elastic hydrogel of hyaluronic acid and chondroitin sulfate as potential cell scaffold materials.

    PubMed

    Ni, Yilu; Tang, Zhurong; Cao, Wanxu; Lin, Hai; Fan, Yujiang; Guo, Likun; Zhang, Xingdong

    2015-03-01

    Natural polysaccharides are extensively investigated as cell scaffold materials for cellular adhesion, proliferation, and differentiation due to their excellent biocompatibility, biodegradability, and biofunctions. However, their application is often severely limited by their mechanical behavior. In this study, a tough and elastic hydrogel scaffold was prepared with hyaluronic acid (HA) and chondroitin sulfate (CS). HA and CS were conjugated with tyramine (TA) and the degree of substitution (DS) was 10.7% and 11.3%, respectively, as calculated by (1)H NMR spectra. The hydrogel was prepared by mixing HA-TA and CS-TA in presence of H2O2 and HRP. The sectional morphology of hydrogels was observed by SEM, static and dynamic mechanical properties were analyzed by Shimadzu electromechanical testing machine and dynamic mechanical thermal analyzer Q800. All samples showed good ability to recover their appearances after deformation, the storage modulus (E') of hydrogels became higher as the testing frequency went up. Hydrogels also showed fatigue resistance to cyclic compression. Mesenchymal stem cells encapsulated in hydrogels showed good cell viability as detected by CLSM. This study suggests that the hydrogels have both good mechanical properties and biocompatibility, and may serve as model systems to explore mechanisms of deformation and energy dissipation or find some applications in tissue engineering.

  14. Comparison between therapeutic antitoxin F(ab)2 fractionated with ammonium sulfate and caprylic acid.

    PubMed

    Redwan, El-Rashdy M

    2006-01-01

    To date, animal derived therapeutic antibodies represent the best and only choice source of antitoxins, especially in developing countries. Furthermore, this industry needs to develop a production protocol to achieve safer products. Recently, several laboratories changed their production protocol from ammonium sulfate (AS) protocol to caprylic acid (CA) fractionation. Our results showed that using the CA protocol leads to improvement in the product quality, as assessed by the albumin and protein content decrease (from 4.75 to 3.54 g/dL and 0.64 to 0.18 g/dL, respectively), which yielded a purer antitoxin product. The F(ab)2 protein aggregate formation and turbidity have been significantly reduced, 4.60 versus 2.55 and 0.046 versus 0.021 (p < 0.01), respectively. However, the anti-complementary activity was also reduced, from 42 to 33. The total IgG content was higher in CA fractionated products than AS materials. The endotoxin content was worrisome in some F(ab)2 products.

  15. Gallic acid attenuates dextran sulfate sodium-induced experimental colitis in BALB/c mice

    PubMed Central

    Pandurangan, Ashok Kumar; Mohebali, Nooshin; Norhaizan, Mohd Esa; Looi, Chung Yeng

    2015-01-01

    Gallic acid (GA) is a polyhydroxy phenolic compound that has been detected in various natural products, such as green tea, strawberries, grapes, bananas, and many other fruits. In inflammatory bowel disease, inflammation is promoted by oxidative stress. GA is a strong antioxidant; thus, we evaluated the cytoprotective and anti-inflammatory role of GA in a dextran sulfate sodium (DSS)-induced mouse colitis model. Experimental acute colitis was induced in male BALB/c mice by administering 2.5% DSS in the drinking water for 7 days. The disease activity index; colon weight/length ratio; histopathological analysis; mRNA expressions of IL-21 and IL-23; and protein expression of nuclear erythroid 2-related factor 2 (Nrf2) were compared between the control and experimental mice. The colonic content of malondialdehyde and the activities of superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase activity were examined as parameters of the redox state. We determined that GA significantly attenuated the disease activity index and colon shortening, and reduced the histopathological evidence of injury. GA also significantly (P<0.05) reduced the expressions of IL-21 and IL-23. Furthermore, GA activates/upregulates the expression of Nrf2 and its downstream targets, including UDP-GT and NQO1, in DSS-induced mice. The findings of this study demonstrate the protective effect of GA on experimental colitis, which is probably due to an antioxidant nature of GA. PMID:26251571

  16. Modified ferrous ammonium sulfate benzoic acid xyelenol orange (MFBX) and thermoluminescent dosimeters--a comparative study.

    PubMed

    Brindha, S; Rose, J V R; Sathyan, S; Singh I, Rabi Raja; Ravindran, B Paul

    2002-06-07

    Radiation dosimetry deals with the determination of absorbed dose to the medium exposed to ionizing radiation. Chemical dosimetry depends on oxidation or reduction of chemicals by ionizing radiation. A ferrous ammonium sulfate benzoic acid xyelenol orange (FBX) dosimeter based on this principle is being used as a clinical dosimeter at present. Certain modifications were carried out in the preparation and storage of the FBX dosimeter to increase its shelf life. The resulting dosimeter was called a modified FBX (MFBX) dosimeter and has been used in our department for the past few years. An extensive study of the dose, dose rate and energy response of the dosimeter was carried out and compared with a thermoluminescent (LiF7) dosimeter. The results obtained were found to be comparable to the thermoluminescent (LiF7) dosimeter. Hence it was concluded that the MFBX dosimeter could be used for phantom dosimetry, data collection and in vivo measurements. Easier preparation and availability of the reagents are added advantages of using MFBX as a clinical dosimeter in small radiotherapy departments.

  17. Temporal MRI characterization of gelatin/hyaluronic acid/chondroitin sulfate sponge for cartilage tissue engineering.

    PubMed

    Chou, Cheng-Hung; Lee, Herng-Sheng; Siow, Tiing Yee; Lin, Ming-Huang; Kumar, Amit; Chang, Yue-Cune; Chang, Chen; Huang, Guo-Shu

    2013-08-01

    A tri-copolymer sponge consisting of gelatin, hyaluronic acid, and chondroitin sulfate (GHC) was designed to mimic the cartilage environment in vivo for cartilage regeneration. The present study aimed to temporally characterize the magnetic resonance relaxation time of GHC constructs in vivo in a rodent heterotopic model. GHC sponges with cells (GHCc) or without cells (GHC) implanted in rat leg muscle were monitored using MRI (4.7 T MR scanner) on day 0, 7, 14, and 21 after implantation. The results revealed that the transverse relaxation time (T2) of GHC constructs decreased significantly over time when compared to the T2 of GHCc constructs. However, the longitudinal relaxation time (T1) of GHCc and GHC constructs remained stable. Moreover, hematoxylin and eosin and immunohistochemical staining with antibodies to S100 protein, and types I and II collagen showed that normal morphology, phenotype, and function of chondrocytes were preserved in the GHCc construct. Thus, we concluded that GHC constructs adequately support chondrocyte growth and function. On top of that, T2 may be a useful tool for monitoring cartilage regeneration in GHC constructs.

  18. Deliquescence behavior of organic/ammonium sulfate aerosol

    NASA Astrophysics Data System (ADS)

    Brooks, Sarah D.; Wise, Matthew E.; Cushing, Melinda; Tolbert, Margaret A.

    2002-10-01

    Recent studies have shown that tropospheric aerosols composed of internal mixtures of organics with sulfates are quite common with the organic composing up to 50% of the particle mass. The influences of the organics on the chemical and physical properties of the aerosol are not known. In this paper, we report the solubility of a series of dicarboxylic acids in saturated ammonium sulfate solution as a function of temperature. We also report the deliquescence relative humidity (DRH) of the pure dicarboxylic acids and of mixtures of dicarboxylic acids with ammonium sulfate. For the systems studied, we find that the presence of water-soluble dicarboxylic acids caused deliquescence to occur at a lower relative humidity (RH) than pure ammonium sulfate. In contrast, the less soluble dicarboxylic acids had no measurable effect on the deliquescence relative humidity of ammonium sulfate.

  19. TARGETING HYALURONIDASE FOR CANCER THERAPY: ANTITUMOR ACTIVITY OF SULFATED HYALURONIC ACID IN PROSTATE CANCER CELLS

    PubMed Central

    Benitez, Anaid; Yates, Travis J.; Lopez, Luis E.; Cerwinka, Wolfgang H.; Bakkar, Ashraf; Lokeshwar, Vinata B.

    2011-01-01

    The tumor cell-derived hyaluronidase HYAL-1 degrades hyaluronic acid (HA) into pro-angiogenic fragments that support tumor progression. Although HYAL-1 is a critical determinant of tumor progression and a marker for cancer diagnosis and metastasis prediction, it has not been evaluated as a target for cancer therapy. Similarly, sulfated hyaluronic acid (sHA) has not been evaluated for biological activity, although it is a HAase inhibitor. In this study we show that sHA is a potent inhibitor of prostate cancer. sHA blocked the proliferation, motility and invasion of LNCaP, LNCaP-AI, DU145 and LAPC-4 prostate cancer cells, also inducing caspase 8-dependent apoptosis associated with downregulation of Bcl-2 and phospho-Bad. sHA inhibited Akt signaling including androgen receptor (AR) phosphorylation, AR-activity, NFkb activation and VEGF expression. These effects were traced to a blockade in complex formation between PI3K and HA receptors and to a transcriptional downregulation of HA receptors, CD44 and RHAMM, along with PI3K inhibition. Angiogenic HA fragments or overexpression of myristoylated-Akt or HA receptors blunted these effects of sHA, implicating a feedback loop between HA receptors and PI3K/Akt signaling in the mechanism of action. In an animal model, sHA strongly inhibited LNCaP-AI prostate tumor growth without causing weight loss or apparent serum-organ toxicity. Inhibition of tumor growth was accompanied by a significant decrease in tumor angiogenesis and an increase in apoptosis index. Taken together, our findings offer mechanistic insights into the tumor-associated HA-HAase system and a preclinical proof-of-concept of the safety and efficacy of sHA to control prostate cancer growth and progression. PMID:21555367

  20. Glucosamine sulfate

    MedlinePlus

    ... Glucosamine Sulphate KCl, Glucosamine-6-Phosphate, GS, Mono-Sulfated Saccharide, Poly-(1->3)-N-Acetyl-2-Amino- ... Sulfate de Glucosamine, Sulfate de Glucosamine 2KCl, SG, Sulfated Monosaccharide, Sulfated Saccharide, Sulfato de Glucosamina. Glucosamine Hydrochloride ...

  1. REDUCTION OF ACIDITY OF NITRIC ACID SOLUTIONS BY USE OF FORMALDEHYDE

    DOEpatents

    Healy, T.V.

    1958-05-20

    A continuous method is described of concentrating by evaporation and reducing the nitrate ion content of an aqueous solution of metallic salts containing nitric acid not in excess of 8N. It consists of heating the solution and then passing formaldehyde into the heated solution to bring about decomposition of the nitric acid. The evolved gases containing NO are contacted countercurrently with an aqueous metal salt solution containing nitric acid in excess of 8N so as to bring about decomposition of the nitric acid and lower the normality to at least 8N, whereupon it is passed into the body of heated solution.

  2. Comparison of the Efficacy of a Sulfuric Acid-Sodium Sulfate Blend and Lactic Acid for the Reduction of Salmonella on Prerigor Beef Carcass Surface Tissue.

    PubMed

    Yang, Xiang; Bullard, Brittney R; Geornaras, Ifigenia; Hu, Shuang; Woerner, Dale R; Delmore, Robert J; Morgan, J Brad; Belk, Keith E

    2017-04-03

    A study was conducted to compare the efficacy of a commercially available sulfuric acid-sodium sulfate blend (SSS) and lactic acid (LA) in reducing inoculated Salmonella populations on beef. Sixty pieces of prerigor beef carcass surface brisket tissue, collected directly from the processing line of a commercial beef processing plant, were cut into two sections (10 by 10 cm each) and spot inoculated (6 to 7 log CFU/cm(2)) on the adipose side with a six-strain mixture of Salmonella. One section per piece of brisket tissue was left untreated (control), while the second section was spray treated (5 s, 15 lb/in(2), and 33 mL/s flow rate) with unheated (21°C) or heated (52°C) solutions of SSS (pH 1.1) or LA (4%). Unheated and heated SSS lowered (P < 0.05) total bacterial counts from 6.3 to 4.6 and 4.3 log CFU/cm(2), respectively. Likewise, unheated and heated LA reduced (P < 0.05) total bacterial counts from 6.3 to 4.7 and 4.4 log CFU/cm(2), respectively. Initial counts of inoculated Salmonella populations (6.1 to 6.2 log CFU/cm(2)) were reduced (P < 0.05) to 4.2 and 3.9 log CFU/cm(2) following treatment with unheated and heated SSS, respectively, and to 3.7 and 3.8 log CFU/cm(2) after treatment with unheated and heated LA, respectively. Overall, the temperature of the chemical solutions had a small (0.3 log CFU/cm(2)), but significant (P < 0.05), effect on total bacterial counts but not (P > 0.05) on Salmonella counts. Regardless of solution temperature, Salmonella counts for LA-treated samples were 0.3 log CFU/cm(2) lower (P < 0.05) than those of samples treated with SSS. These results indicate that both unheated and heated solutions of SSS and LA are effective interventions for reducing Salmonella contamination on prerigor beef carcass surface tissue.

  3. Method for liquid chromatographic extraction of strontium from acid solutions

    DOEpatents

    Horwitz, E. Philip; Dietz, Mark L.

    1992-01-01

    A method and apparatus for extracting strontium and technetium values from biological, industrial and environmental sample solutions using a chromatographic column is described. An extractant medium for the column is prepared by generating a solution of a diluent containing a Crown ether and dispersing the solution on a resin substrate material. The sample solution is highly acidic and is introduced directed to the chromatographic column and strontium or technetium is eluted using deionized water.

  4. Hygroscopic and phase separation properties of ammonium sulfate/organics/water ternary solutions

    NASA Astrophysics Data System (ADS)

    Zawadowicz, M. A.; Proud, S. R.; Seppalainen, S. S.; Cziczo, D. J.

    2015-08-01

    Atmospheric aerosol particles are often partially or completely composed of inorganic salts, such as ammonium sulfate and sodium chloride, and therefore exhibit hygroscopic properties. Many inorganic salts have well-defined deliquescence and efflorescence points at which they take up and lose water, respectively. Field measurements have shown that atmospheric aerosols are not typically pure inorganic salt, instead, they often also contain organic species. There is ample evidence from laboratory studies that suggests that mixed particles exist in a phase-separated state, with an aqueous inorganic core and organic shell. Although phase separation has not been measured in situ, there is no reason it would not also take place in the atmosphere. Here, we investigate the deliquescence and efflorescence points, phase separation and ability to exchange gas-phase components of mixed organic and inorganic aerosol using a flow tube coupled with FTIR (Fourier transform infrared) spectroscopy. Ammonium sulfate aerosol mixed with organic polyols with different O : C ratios, including 1,4-butanediol, glycerol, 1,2,6-hexanetriol, 1,2-hexanediol, and 1,5-pentanediol have been investigated. Those constituents correspond to materials found in the atmosphere in great abundance and, therefore, particles prepared in this study should mimic atmospheric mixed-phase aerosol particles. Some results of this study tend to be in agreement with previous microscopy experiments, but others, such as phase separation properties of 1,2,6-hexanetriol, do not agree with previous work. Because the particles studied in this experiment are of a smaller size than those used in microscopy studies, the discrepancies found could be a size-related effect.

  5. Hygroscopic and phase separation properties of ammonium sulfate/organic/water ternary solutions

    NASA Astrophysics Data System (ADS)

    Zawadowicz, M. A.; Proud, S. R.; Seppalainen, S. S.; Cziczo, D. J.

    2015-03-01

    Atmospheric aerosol particles are often partially or completely composed of inorganic salts, such as ammonium sulfate and sodium chloride, and therefore exhibit hygroscopic properties. Many inorganic salts have well-defined deliquescence and efflorescence points at which they take up and lose water, respectively. Deliquescence and efflorescence of simple inorganic salt particles have been investigated by a variety of methods, such as IR spectroscopy, tandem mobility analysis and electrodynamic balance. Field measurements have shown that atmospheric aerosols are not typically pure inorganic salt, instead they often also contain organic species. There is ample evidence from laboratory studies that suggests that mixed particles exist in a phase-separated state, with an aqueous inorganic core and organic shell. Although phase separation has not been measured in situ, there is no reason it would not also take place in the atmosphere. Many recent studies have focused on microscopy techniques that require deposition of the aerosol on a glass slide, possibly changing its surface properties. Here, we investigate the deliquescence and efflorescence points, phase separation and ability to exchange gas-phase components of mixed organic and inorganic aerosol using a flow tube coupled with FTIR spectroscopy. Ammonium sulfate aerosol mixed with organic polyols with different O : C ratios, including 1,4-butanediol, glycerol, 1,2,6-hexanetriol, 1,2-hexanediol, and 1,5-pentanediol have been investigated. Those constituents correspond to materials found in the atmosphere in great abundance, and therefore, particles prepared in this study should mimic atmospheric mixed phase aerosol particles. The results of this study tend to be in agreement with previous microscopy experiments, with several key differences, which possibly reveal a size-dependent effect on phase separation in organic/inorganic aerosol particles.

  6. Recovery of rhodium(III) from solutions and industrial wastewaters by a sulfate-reducing bacteria consortium.

    PubMed

    Ngwenya, Nonhlanhla; Whiteley, Chris G

    2006-01-01

    A quantitative analysis of the rate of removal of rhodium(III) by a resting sulfate-reducing bacteria (SRB) consortium under different initial rhodium and biomass concentrations, pH, temperature, and electron donor was studied. Rhodium speciation was found to be the main factor controlling the rate of its removal from solution. SRB cells were found to have a higher affinity for anionic rhodium species, as compared to both cationic and neutral species, which become abundant when speciation equilibrium was reached. Consequently, a pH-dependent rate of rhodium removal from solution was observed. The maximum SRB uptake capacity for rhodium was found to be 66 mg of rhodium per gram of resting SRB biomass. Electron microscopy studies revealed a time-dependent localization and distribution of rhodium precipitates, initially intracellularly and then extracellularly, suggesting the involvement of an enzymatic reductive precipitation process. When a purified hydrogenase enzyme was incubated with rhodium chloride solution under hydrogen, 88% of the rhodium was removed within 1 h, whereas with a soluble extract from SRB 77% was removed within 10 min. Due to the low pH of the industrial effluent (1.31), the enzymatic reduction of rhodium by the purified hydrogenase was greatly limited, and it was apparent that an industrial effluent pretreatment was necessary before the application of an enzymatic treatment. In the present study, however, it was established that SRB are good candidates for the enzymatic recovery of rhodium from both aqueous solution and industrial effluent.

  7. Effects of buffered vinegar and sodium dodecyl sulfate plus levulinic acid on Salmonella Typhimurium survival, shelf-life, and sensory characteristics of ground beef patties.

    PubMed

    Stelzleni, Alexander M; Ponrajan, Amudhan; Harrison, Mark A

    2013-09-01

    The inclusion of two sources of buffered vinegar and sodium dodecyl sulfate plus levulinic acid were studied as interventions for Salmonella Typhimurium and for their effect on shelf-life and sensory characteristics of ground beef. For the Salmonella challenge, beef trimmings (80/20) were inoculated then treated with 2% (w/v) liquid buffered vinegar (LVIN), 2.5% (w/w) powdered buffered vinegar (PVIN), a solution containing 1.0% levulinic acid plus 0.1% sodium dodecyl sulfate (SDLA) at 10% (w/v), or had no intervention applied (CNT). The same trim source and production methods were followed during production of patties for shelf-life and sensory testing without inoculation. SDLA patties had the largest reduction (P<0.05; 0.70 log CFU/g) of Salmonella. However, LVIN and PVIN had the least (P<0.05) psychrotrophic growth. SDLA patties had more purge (P<0.05) and lower (P<0.05) subjective color scores. There were not large differences in sensory characteristics, except PVIN exhibited stronger off-flavor (P<0.05).

  8. Degradation of dissolved organic monomers and short-chain fatty acids in sandy marine sediment by fermentation and sulfate reduction

    NASA Astrophysics Data System (ADS)

    Valdemarsen, Thomas; Kristensen, Erik

    2010-03-01

    The decay of a wide range of organic monomers (short-chain volatile fatty acids (VFA's), amino acids, glucose and a pyrimidine) was studied in marine sediments using experimental plug flow-through reactors. The reactions were followed in the presence and absence of 10 mM SO 42-. Degradation stoichiometry of individual monomers (inflow concentration of 6 mM organic C) was traced by measuring organic (VFA's, amino acids) and inorganic (CO 2, NH 4+, SO 42-) compounds in the outflow. Fermentation of amino acids was efficient and complete during passage through anoxic sediment reactors. Aliphatic amino acids (alanine, serine and glutamate) were primarily recovered as CO 2 (24-34%), formate (3-22%) and acetate (41-83%), whereas only ˜1/3 of the aromatic amino acid (tyrosine) was recovered as CO 2 (13%) and acetate (20%). Fermentation of glucose and cytosine was also efficient (78-86%) with CO 2 (30-35%), formate (3%) and acetate (28-33%) as the primary products. Fermentation of VFA's (acetate, propionate and butyrate), on the other hand, appeared to be product inhibited. The presence of SO 42- markedly stimulated VFA degradation (29-45% efficiency), and these compounds were recovered as CO 2 (17% for butyrate to 100% for acetate) and acetate (51% and 82% for propionate and butyrate, respectively). When reaction stoichiometry during fermentation is compared with compound depletion during sulfate reduction, the higher proportion CO 2 recovery is consistent with lower acetate and formate accumulation. Our results therefore suggest that fermentation reactions mediate the initial degradation of added organic compounds, even during active sulfate reduction. Fermentative degradation stoichiometry also suggested significant H 2 production, and >50% of sulfate reduction appeared to be fuelled by H 2. Furthermore, our results suggest that fermentation was the primary deamination step during degradation of the amino acids and cytosine.

  9. Acid rain: Engineering solutions, regulatory aspects

    SciTech Connect

    Schwieger, R.G.; Elliott, T.C.

    1985-01-01

    Keeping up with efforts to control acid rain, this reference presents current scientific aspects associated with the problem of political and legislative concerns and ideas for developing effective mitigation programs at reasonable cost. The contributors are the authorities in attendance at the Second International Conference on Acid Rain - and this work represents the first time engineers and managers with firsthand knowledge of systems and equipment to reduce SO/sub 2/ and NO/sub x/ emissions gathered in one place. Throughout the book, some 200 tables, charts, diagrams, and photographs augment the textual material.

  10. Macroalgal biomonitors of trace metal contamination in acid sulfate soil aquaculture ponds.

    PubMed

    Gosavi, K; Sammut, J; Gifford, S; Jankowski, J

    2004-05-25

    Earthen shrimp aquaculture ponds are often impacted by acid sulfate soils (ASS), typically resulting in increased disease and mortality of cultured organisms. Production losses have been attributed to either low pH or to elevated concentrations of toxic metals, both direct products of pyrite oxidation in ASS. The standard farm management practice to minimise effects of pyrite oxidation is to maintain pH of pond waters above 5, based on the assumption that dissolved metal bioavailability is negligible at this pH. This study aimed to test the validity of this assumption, and therefore elucidate a possible role of toxic heavy metals in observed decreases in farm productivity. Metal bioaccumulation in four genera of macroalgae, Ulva sp., Enteromorpha sp., Cladophora sp. and Chaetomorpha sp., sampled from ASS-affected shrimp aquaculture ponds were measured using inductively coupled plasma-optical emission spectroscopy (ICP-OES) to assess the relative bioavailability of dissolved metals within the system. Results showed that all four genera of macroalgae accumulated appreciable quantities of Fe, Al, Zn, Cd, Cu, As and Pb. Iron and Al, the most common metals mobilised from ASS, were both accumulated in all algal genera to concentrations three orders of magnitude greater than all other metals analysed. These findings indicate that dissolved heavy metals are indeed bioavailable within the aquaculture pond system. A literature search of heavy metal bioaccumulation by these algal genera revealed concentrations recorded in this study are comparable to highly contaminated environments, such as those exposed to urban, industrial and mining pollution. The results of this study indicate that dissolved metal bioavailability in many earthen shrimp aquaculture ponds may be higher than previously thought.

  11. Decomposition Studies of Triphenylboron, Diphenylborinic Acid and Phenylboric Acid in Aqueous Alkaline Solutions Containing Copper

    SciTech Connect

    Crawford, C.L.; Peterson, R. A.

    1997-02-11

    This report documents the copper-catalyzed chemical kinetics of triphenylboron, diphenylborinic acid and phenylboric acid (3PB, 2PB and PBA) in aqueous alkaline solution contained in carbon-steel vessels between 40 and 70 degrees C.

  12. Recovery of transplutonium elements from aqueous and water-ethanol solutions of sulfuric acid and their separation from other actinides

    SciTech Connect

    Guseva, L.I.; Tikhomirova, G.S.; Stepushkina, V.V.

    1988-05-01

    The behavior of Am, Cm, Bk, Cf, Es, and other actinides, as well as Zr, on anion and cation exchangers in aqueous and water-ethanol solutions of sulfuric acid as a function of the various components of the solution has been investigated. It has been discovered that the presence of ethanol in sulfuric acid solutions causes an increase in the distribution coefficients both on cation exchangers and on anion exchangers. The possibility of the use of ion exchangers for the preconcentration and separation of transplutonium elements from U, Np, Pu, Zr, and other elements which form strong complexes with sulfate ions over a broad range of concentrations of sulfuric acid has been demonstrated.

  13. Antimicrobial Efficacy of a Sulfuric Acid and Sodium Sulfate Blend, Peroxyacetic Acid, and Cetylpyridinium Chloride against Salmonella on Inoculated Chicken Wings.

    PubMed

    Scott, Brittney R; Yang, Xiang; Geornaras, Ifigenia; Delmore, Robert J; Woerner, Dale R; Reagan, James O; Morgan, J Brad; Belk, Keith E

    2015-11-01

    Studies were conducted to evaluate the efficacy of a commercial blend of sulfuric acid and sodium sulfate (SSS) in reducing Salmonella on inoculated whole chilled chicken wings and to compare its efficacy to peroxyacetic acid (PAA) and cetylpyridinium chloride (CPC). Wings were spot inoculated (5 to 6 log CFU/ml of sample rinsate) with a five-strain mixture of novobiocin- and nalidixic acid-resistant Salmonella and then left untreated (control) or treated by immersing individual wings in 350 ml of antimicrobial solution. An initial study evaluated two treatment immersion times, 10 and 20 s, of SSS (pH 1.1) and compared cell recoveries following rinsing of treated samples with buffered peptone water or Dey/Engley neutralizing broth. In a second study, inoculated wings were treated with SSS (pH 1.1; 20 s), PAA (700 ppm, 20 s), or CPC (4,000 ppm, 10 s) and analyzed for survivors immediately after treatment (0 h) and after 24 h of aerobic storage at 4°C. Color and pH analyses were also conducted in the latter study. Recovery of Salmonella survivors following treatment with SSS (10 or 20 s) was not (P ≥ 0.05) affected by the type of cell recovery rinse solution (buffered peptone water or Dey/Engley neutralizing broth), but there was an effect (P < 0.05) of SSS treatment time. Immersion of samples for 10 or 20 s in SSS resulted in pathogen reductions of 0.8 to 0.9 and 1.1 to 1.2 log CFU/ml, respectively. Results of the second study showed that there was an interaction (P < 0.05) between antimicrobial type and storage time. Efficacy against Salmonella at 0 h increased in the order CPC , SSS , PAA; however, after 24 h of aerobic storage, pathogen counts of SSS- and PAA-treated wings did not differ (P ≥ 0.05). Overall, the results indicated that SSS applied at pH 1.1 for 20 s was an effective antimicrobial intervention to reduce Salmonella contamination on chicken wings.

  14. Metal and acidity fluxes controlled by precipitation/dissolution cycles of sulfate salts in an anthropogenic mine aquifer

    NASA Astrophysics Data System (ADS)

    Cánovas, C. R.; Macías, F.; Pérez-López, R.

    2016-05-01

    Underground mine drainages are extremely difficult to study due to the lack of information about the flow path and source proximity in relation to the outflow adit. Geochemical processes controlling metals and acidity fluxes in a complex anthropogenic mine aquifer in SW Spain during the dry and rainy season were investigated by geochemical and statistical tools. High concentrations of acidity, sulfate, metals and metalloids (e.g. Fe, Cu, Zn, As, Cd, Ni, Co) were observed due to intense sulfide oxidation processes. The high residence time inside the anthropogenic aquifer, around 40 days, caused the release of significant quantities of metals linked to host rocks (e.g. Al, Ca, Ge, Li, Mg, REE). The most outstanding characteristic of the acid mine drainage (AMD) outflows is the existence of higher Fe/SO4 molar ratios than those theoretical of pyrite (0.50) during most of the monitored period, due to a fire which occurred in 1949 and remained active for decades. Permanent and temporal retention mechanisms of acidity and metals were observed in the galleries. Once released from sulfide oxidation, Pb and As are sorbed on Fe oxyhydroxysulfate or precipitated as low solubility minerals (i.e. anglesite) inside the galleries. The precipitation of evaporitic sulfate salts during the dry season and the subsequent re-dissolution after rainfall control the fluxes of acidity and main metals (i.e. Fe, Mg, Al) from this anthropogenic aquifer. Some elements, such as Cd, Cu, Ni, REE and Zn, are retained in highly soluble sulfate salts while other elements, such as Ge, Pb and Sc, have a lower response to washout processes due to its incorporation in less soluble sulfate salts. In this way, metal concentration during the washout processes would be controlled by the proportion and solubility of each type of evaporitic sulfate salt stored during the dry season. The recovery of metals of economic interest contained in the AMD could help to self-finance the remediation of these waters in

  15. Vacuum-jacketed hydrofluoric acid solution calorimeter

    USGS Publications Warehouse

    Robie, R.A.

    1965-01-01

    A vacuum-jacketed metal calorimeter for determining heats of solution in aqueous HF was constructed. The reaction vessel was made of copper and was heavily gold plated. The calorimeter has a cooling constant of 0.6 cal-deg -1-min-1, approximately 1/4 that of the air-jacketed calorimeters most commonly used with HF. It reaches equilibrium within 10 min after turning off the heater current. Measurements of the heat of solution of reagent grade KCl(-100 mesh dried 2 h at 200??C) at a mole ratio of 1 KCl to 200 H2O gave ??H = 4198??11 cal at 25??C. ?? 1965 The American Institute of Physics.

  16. Decomposition of pertoluic acid in chlorobenzene solution

    SciTech Connect

    Ariko, N.G.; Kornilova, N.N.; Mitskevich, N.I.

    1985-09-01

    The kinetics and composition of the decomposition products of pertoluic acid in chlorobenzene at 353-403 K were studied. The activation energy of the gross decomposition is 82.4 is identical to 6 kJ/mole; the main products are pertoluic acid and CO/sub 2/. On the basis of the dependence of the yields of CO/sub 2/ on the concentration of the peracid (0.01-0.05 M), it was concluded that the peracid undergoes radical breakdown, and induced breakdown with abstraction of a H atom from OOH group occurs. The formation of toluence (conversion product of the CH/sub 3/-C/sub 6/H/sub 4/. radical) and O/sub 2/ was demonstrated.

  17. Improved method for extracting lanthanides and actinides from acid solutions

    DOEpatents

    Horwitz, E.P.; Kalina, D.G.; Kaplan, L.; Mason, G.W.

    1983-07-26

    A process for the recovery of actinide and lanthanide values from aqueous acidic solutions uses a new series of neutral bi-functional extractants, the alkyl(phenyl)-N,N-dialkylcarbamoylmethylphosphine oxides. The process is suitable for the separation of actinide and lanthanide values from fission product values found together in high-level nuclear reprocessing waste solutions.

  18. Polymerization of beta-amino acids in aqueous solution

    NASA Technical Reports Server (NTRS)

    Liu, R.; Orgel, L. E.; Bada, J. L. (Principal Investigator)

    1998-01-01

    We have compared carbonyl diimidazole (CDI) and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDAC) as activating agents for the oligomerization of negatively-charged alpha- and beta-amino acids in homogeneous aqueous solution. alpha-Amino acids can be oligomerized efficiently using CDI, but not by EDAC. beta-Amino acids can be oligomerized efficiently using EDAC, but not by CDI. Aspartic acid, an alpha- and beta-dicarboxylic acid is oligomerized efficiently by both reagents. These results are explained in terms of the mechanisms of the reactions, and their relevance to prebiotic chemistry is discussed.

  19. Clues on Acid-Sulfate Alteration and Hematite Formation on Earth and Mars From Iron Isotopic Analyses of Terrestrial Analogues From Hawaii

    NASA Technical Reports Server (NTRS)

    Nie, N. X.; Dauphas, N.; Morris, R. V

    2017-01-01

    The Mars Exploration Rover mission revealed the presence of rocks and minerals indicative of water-rock interactions on Mars. A range of mineralogies have been identified, including hematite spherules (i.e., blueberries), jarosite, Mg-, Ca-sulfates, silica-rich materials and silicate relics from basaltic rocks. The mineral assemblages have been interpreted to be derived from acid-sulfate alteration of basaltic materials. Indeed, the chemical compositions of rocks and soils at Home Plate in Gusev Crater follow the trends expected for acid-sulfate alteration.

  20. Method for incorporating radioactive phosphoric acid solutions in concrete

    DOEpatents

    Wolf, G.A.; Smith, J.W.; Ihle, N.C.

    1982-07-08

    A method for incorporating radioactive phosphoric acid solutions in concrete is described wherein the phosphoric acid is reacted with Ca(OH)/sub 2/ to form a precipitate of hydroxyapatite and the hydroxyapatite is mixed with Portland cement to form concrete.

  1. Method for incorporating radioactive phosphoric acid solutions in concrete

    DOEpatents

    Wolf, Gary A [Kennewick, WA; Smith, Jeffrey W [Lancaster, OH; Ihle, Nathan C [Walla Walla, WA

    1984-01-01

    A method for incorporating radioactive phosphoric acid solutions in concrete is described wherein the phosphoric acid is reacted with Ca(OH).sub.2 to form a precipitate of hydroxyapatite and the hydroxyapatite is mixed with portland cement to form concrete.

  2. Resilience of sulfate-reducing granular sludge against temperature, pH, oxygen, nitrite, and free nitrous acid.

    PubMed

    Hao, Tianwei; Mackey, Hamish R; Guo, Gang; Liu, Rulong; Chen, Guanghao

    2016-10-01

    Sulfate-reducing granular sludge has recently been developed and characterized in detail as part of the development of the sulfate reduction, autotrophic denitrification, nitrification integrated (SANI) process. However, information regarding temperature of granules to environmental fluctuation is lacking, an aspect that is important in dealing with real wastewater. A comprehensive assessment of sulfate-reducing granular sludge performance under various environmental conditions was thus conducted in this study, including temperature, pH, oxygen, nitrite, and free nitrous acid (FNA) as possible encountering conditions in the removal of organics and/or nitrate. Specific chemical oxygen demand removal rate of the granules was determined to be reduced by 65 % when the temperature varied between 10-15 °C, reduced by 70 % when dissolved oxygen (DO) was 0.5 mg/L or greater, and at least, reduced by 75 % when nitrite was 30 mg N/L or above. Nevertheless, the sludge activity recovered by 82, 100, and 86 % from exposure to high oxygen and nitrite and low temperature levels, respectively. Combined inhibition of nitrite and FNA on the sludge is strong and complex, while FNA alone reduced cell viability from 60 to 40 % when its concentration increased to 2.3 mg N/L. The present study demonstrates that sulfate-reducing bacteria (SRB) granules possess high resilience against varying environmental conditions, showing the high application potential of sulfate-reducing granular sludge in dealing with brackish and saline industrial or domestic wastewaters.

  3. Physical state and acidity of inorganic sulfate can regulate the production of secondary organic material from isoprene photooxidation products.

    PubMed

    Kuwata, Mikinori; Liu, Yingjun; McKinney, Karena; Martin, Scot T

    2015-02-28

    The production of secondary organic material (SOM) by the reactive uptake of isoprene photooxidation products was investigated using partially to wholly neutralized sulfuric acid particles. The experiments were performed at a relative humidity (RH) of <5% and a temperature of 20 °C. The extent X of neutralization was adjusted from that of sulfuric acid (X = 0) to that of ammonium sulfate (X = 1). Significant SOM production was observed only for X < 0.7. The threshold of 0.7 corresponded to the transition point of the sulfate particles from aqueous to solid for <5% RH. The phase transition of inorganic sulfate therefore regulated the particle-phase reactions that produce isoprene SOM, at least for the investigated conditions. For aqueous particles, a decreasing extent of neutralization was associated with increasing production of SOM, including increased production of oligomers and organosulfates. These results can underpin treatments of phase-dependent SOM production within chemical transport models, thereby improving the accuracy of simulations of biogenic-anthropogenic interactions in the atmosphere and the associated impacts of aerosol particles on climate and air quality.

  4. Synthesis and olfactory activity of unnatural, sulfated 5β-bile acid derivatives in the sea lamprey (Petromyzon marinus)

    PubMed Central

    Burns, Aaron C.; Sorensen, Peter W.

    2011-01-01

    A variety of unnatural bile acid derivatives (9a–9f) were synthesized and used to examine the specificity with which the sea lamprey (Petromyzon marinus) olfactory system detects these compounds. These compounds are analogs of petromyzonol sulfate (PS, 1), a component of the sea lamprey migratory pheromone. Both the stereochemical configuration at C5 (i.e., 5α vs. 5β) and the extent and sites of oxygenation (hydroxylation or ketonization) of the bile acid derived steroid skeleton were evaluated by screening the compounds for olfactory activity using electro-olfactogram recording. 5β-Petromyzonol sulfate (9a) elicited a considerable olfactory response at sub-nanomolar concentration. In addition, less oxygenated systems (i.e., 9b–9e) elicited olfactory responses, albeit with less potency. The sea lamprey sex pheromone mimic 9f (5β-3-ketopetromyzonol sulfate) was also examined and found to produce a much lower olfactory response. Mixture studies conducted with 9a and PS (1) suggest that stimulation is occurring via similar modes of activation, demonstrating a relative lack of specificity for recognition of the allo-configuration (i.e., 5α) in sea lamprey olfaction. This attribute could facilitate design of pheromone analogs to control this invasive species. PMID:21145335

  5. Phosphorylation of glyceric acid in aqueous solution using trimetaphosphate

    NASA Astrophysics Data System (ADS)

    Kolb, Vera; Orgel, Leslie E.

    1996-02-01

    The phosphorylation of glyceric acid is an interesting prebiotic reaction because it converts a simple, potentially prebiotic organic molecule into phosphate derivatives that are central to carbohydrate metabolism. We find that 0.05 M glyceric acid in the presence of 0.5 M trimetaphosphate in alkaline solution gives a mixture of 2- and 3-phosphoglyceric acids in combined yields of up to 40%.

  6. Phosphorylation of Glyceric Acid in Aqueous Solution Using Trimetaphosphate

    NASA Technical Reports Server (NTRS)

    Kolb, Vera; Orgel, Leslie E.

    1996-01-01

    The phosphorylation of glyceric acid is an interesting prebiotic reaction because it converts a simple, potentially prebiotic organic molecule into phosphate derivatives that are central to carbohydrate metabolism. We find that 0.05 M glyceric acid in the presence of 0.5 M trimetaphosphate in alkaline solution gives a mixture of 2- and 3-phosphoglyceric acids in combined yields of up to 40%.

  7. Reductions of Salmonella enterica on chicken breast by thymol, acetic acid, sodium dodecyl sulfate or hydrogen peroxide combinations as compared to chlorine wash.

    PubMed

    Lu, Y; Wu, C

    2012-01-03

    Poultry products are important vehicles for Salmonella transmission to humans and have been incriminated in several Salmonella outbreaks. Thymol (THY) from thyme oil has wide inhibitory effects against foodborne pathogens including Salmonella, and has shown great potential as a natural alternative to chlorine. In order to improve the cost-effectiveness of thymol-based washing solutions, formulas of THY with combination of organic acid or surfactant were developed and their efficacies to reduce Salmonella on chicken breast were investigated in the current study. Surface-inoculated chicken breasts were washed with the two thymol-based washing solutions: 0.2 mg/mL THY+5% (w/v) sodium dodecyl sulfate (SDS)+2 mg/mL acetic acid (AA) or 0.2 mg/mL THY+2 mg/mL AA for 2 min. Both solutions achieved around 2.2 log reductions of Salmonella on chicken breast and their efficacy was comparable to log reduction obtained by 200 ppm chlorine washing. Addition of SDS did not result in more log reduction of Salmonella on chicken meat samples. More than 3.3 log reduction in the used THY washing solutions was determined and it was similar to log reduction from the spent chlorine solution. None of these antimicrobial agents changed the pH and texture values of chicken breasts. Therefore, 0.2 mg/mL THY+2 mg/mL AA has great potential to be a natural alternative to chlorine-based washing solution for reducing Salmonella contamination on chicken breast meat.

  8. The solution behavior of poly(vinylpyrrolidone): its clouding in salt solution, solvation by water and isopropanol, and interaction with sodium dodecyl sulfate.

    PubMed

    Dan, Abhijit; Ghosh, Soumen; Moulik, Satya P

    2008-03-27

    This article deals with the solution properties of poly(vinylpyrrolidone) (PVP) in salt and surfactant environment. The cloud point (CP) of PVP has been found to be induced by the salts NaCl, KCl, KBr, Na2SO4, MgSO4, and Na3PO4. On the basis of CP values for a salt at different [PVP], the energetics of the clouding process have been estimated. The effect of the surfactant, sodium dodecyl sulfate (SDS), on the salt-induced CP has also been studied, and reduction in CP at low [SDS] and increase in CP at high [SDS] have been observed. The water vapor adsorption of PVP has been determined by isopiestic method. The results display a BET Type III isotherm whose analysis has helped to obtain the monolayer capacity of PVP and formation of multilayer on it. The solvation of PVP in a solution of water and a water-isopropanol mixture has been determined by conductometry from which contribution of the individual components were estimated. The interaction of PVP with SDS in solution led to formation of a complex entity, which has been studied also by conductometry adopting a binding-equilibrium scheme. SDS has been found to undergo two types of binding as monomers in the pre- critical aggregation concentration (CAC) range and as small clusters in the post CAC region. The stoichiometries of binding and binding constant were evaluated.

  9. Reduction of Plutonium in Acidic Solutions by Mesoporous Carbons

    SciTech Connect

    Parsons-Moss, Tashi; Jones, Stephen; Wang, Jinxiu; Wu, Zhangxiong; Uribe, Eva; Zhao, Dongyuan; Nitsche, Heino

    2015-12-19

    Batch contact experiments with several porous carbon materials showed that carbon solids spontaneously reduce the oxidation state of plutonium in 1-1.5 M acid solutions, without significant adsorption. The final oxidation state and rate of Pu reduction varies with the solution matrix, and also depends on the surface chemistry and surface area of the carbon. It was demonstrated that acidic Pu(VI) solutions can be reduced to Pu(III) by passing through a column of porous carbon particles, offering an easy alternative to electrolysis with a potentiostat.

  10. Competitive Oxidation of Volatile Fatty Acids by Sulfate- and Nitrate-Reducing Bacteria from an Oil Field in Argentina▿ †

    PubMed Central

    Grigoryan, Aleksandr A.; Cornish, Sabrina L.; Buziak, Brenton; Lin, Shiping; Cavallaro, Adriana; Arensdorf, Joseph J.; Voordouw, Gerrit

    2008-01-01

    Acetate, propionate, and butyrate, collectively referred to as volatile fatty acids (VFA), are considered among the most important electron donors for sulfate-reducing bacteria (SRB) and heterotrophic nitrate-reducing bacteria (hNRB) in oil fields. Samples obtained from a field in the Neuquén Basin, western Argentina, had significant activity of mesophilic SRB, hNRB, and nitrate-reducing, sulfide-oxidizing bacteria (NR-SOB). In microcosms, containing VFA (3 mM each) and excess sulfate, SRB first used propionate and butyrate for the production of acetate, which reached concentrations of up to 12 mM prior to being used as an electron donor for sulfate reduction. In contrast, hNRB used all three organic acids with similar kinetics, while reducing nitrate to nitrite and nitrogen. Transient inhibition of VFA-utilizing SRB was observed with 0.5 mM nitrite and permanent inhibition with concentrations of 1 mM or more. The addition of nitrate to medium flowing into an upflow, packed-bed bioreactor with an established VFA-oxidizing SRB consortium led to a spike of nitrite up to 3 mM. The nitrite-mediated inhibition of SRB led, in turn, to the transient accumulation of up to 13 mM of acetate. The complete utilization of nitrate and the incomplete utilization of VFA, especially propionate, and sulfate indicated that SRB remained partially inhibited. Hence, in addition to lower sulfide concentrations, an increase in the concentration of acetate in the presence of sulfate in waters produced from an oil field subjected to nitrate injection may indicate whether the treatment is successful. The microbial community composition in the bioreactor, as determined by culturing and culture-independent techniques, indicated shifts with an increasing fraction of nitrate. With VFA and sulfate, the SRB genera Desulfobotulus, Desulfotignum, and Desulfobacter as well as the sulfur-reducing Desulfuromonas and the NR-SOB Arcobacter were detected. With VFA and nitrate, Pseudomonas spp. were

  11. Self-assembled nanoparticles based on chondroitin sulfate-deoxycholic acid conjugates for docetaxel delivery: Effect of degree of substitution of deoxycholic acid.

    PubMed

    Liu, Mengrui; Du, Hongliang; Zhai, Guangxi

    2016-10-01

    Hydrophobically-modified polymers based on chondroitin sulfate with different degree of substitution (DS) of deoxycholic acid (DOCA) were developed for docetaxel delivery. Chondroitin sulfate-deoxycholic acid (CSAD) bioconjugates were synthesized via the linker of adipic dihydrazide by amide bond. They were characterized with spherical shape, mean diameter of around 165.2nm and negative zeta potential (-14.87 to -20.53mV). An increase of DOCA DS reduced size of nanoparticles, while increasing drug loading efficiency. Drug release in vitro showed a triphasic sustained pattern and higher accumulative drug release percentage was observed with increased DS of DOCA on polymer. Self-assemblies with higher DS also had enhanced internalization of nanoparticles and stronger cytotoxicity at the cellular level. The self-assemble nanoparticles demonstrate to be excellent targeting drug delivery systems and the desired therapeutics can be achieved via the alteration of DS.

  12. Incorporation of Np(V) and U(VI) in carbonate and sulfate minerals crystallized from aqueous solution

    NASA Astrophysics Data System (ADS)

    Balboni, Enrica; Morrison, Jessica M.; Wang, Zheming; Engelhard, Mark H.; Burns, Peter C.

    2015-02-01

    The neptunyl Np(V)O2+ and uranyl U(VI)O22+ ions are soluble in groundwater, although their interaction with minerals in the subsurface may impact their mobility. One mechanism for the immobilization of actinyl ions in the subsurface is co-precipitation in low-temperature minerals that form naturally, or that are induced to form as part of a remediation strategy. Important differences in the crystal-chemical behavior of the Np(V) neptunyl and U(VI) uranyl ions suggest their behavior towards incorporation into growing crystals may differ significantly. Using a selection of low-temperature minerals synthesized in aqueous systems under ambient conditions, this study examines the factors that impact the structural incorporation of the Np(V) neptunyl and U(VI) uranyl ions in carbonate and sulfate minerals. Calcite (CaCO3), aragonite (CaCO3), gypsum (CaSO4·2H2O), strontianite (SrCO3), cerussite (PbCO3), celestine (SrSO4), and anglesite (PbSO4) were synthesized from aqueous solutions containing either 400-1000 ppm of U(VI) or Np(V) relative to the divalent cation present in the system. The synthetic products were investigated by inductively coupled plasma mass spectrometry, luminescence and time resolved luminescence spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy. Amongst the carbonate minerals, calcite significantly favors Np(V) incorporation over U(VI). U(VI) and Np(V) are incorporated in aragonite and strontianite in similar amounts, whereas cerussite did not incorporate either U(VI) or Np(V) under the synthesis conditions. The sulfate minerals weakly interact with the actinyl ions, relative to the carbonate minerals. Incorporation of U(VI) and Np(V) in celestine was observed at the level of a few tens of ppm; anglesite and gypsum did not incorporate detectable U(VI) or Np(V). Luminescence spectra of the uranyl incorporated in aragonite and strontianite are consistent with a uranyl unit coordinated by three bidentate CO32- groups

  13. REMOVAL OF CHLORIDE FROM ACIDIC SOLUTIONS USING NO2

    SciTech Connect

    Visser, A; Robert Pierce, R; James Laurinat, J

    2006-08-22

    Chloride (Cl{sup -}) salt processing in strong acids is used to recycle plutonium (Pu) from pyrochemical residues. The Savannah River National Laboratory (SRNL) is studying the potential application of nitrogen dioxide (NO{sub 2}) gas to effectively convert dissolved pyrochemical salt solutions to chloride-free solutions and improve recovery operations. An NO{sub 2} sparge has been shown to effectively remove Cl{sup -} from solutions containing 6-8 M acid (H{sup +}) and up to 5 M Cl{sup -}. Chloride removal occurs as a result of the competition of at least two reactions, one which is acid-dependent. Below 4 M H+, NO2 reacts with Cl- to produce nitrosyl chloride (ClNO). Between 6 M and 8 M H{sup +}, the reaction of hydrochloric acid (HCl) with nitric acid (HNO{sub 3}), facilitated by the presence of NO{sub 2}, strongly affects the rate of Cl{sup -} removal. The effect of heating the acidic Cl{sup -} salt solution without pre-heating the NO{sub 2} gas has minimal effect on Cl{sup -} removal rates when the contact times between NO{sub 2} and the salt solution are on the order of seconds.

  14. Visible-near-infrared reflectance spectroscopy of volcanic acid-sulfate alteration in Nicaragua: Analogs for early Mars

    NASA Astrophysics Data System (ADS)

    Marcucci, Emma C.; Hynek, Brian M.; Kierein-Young, Kathryn S.; Rogers, K. L.

    2013-10-01

    Acid-sulfate weathering at Nicaraguan hydrothermal sites Cerro Negro, Momotombo, and Telica volcanoes and Hervidores de San Jacinto mudpots was characterized as an analog for similar processes that likely operated on early Mars. In situ mineralogical analyses were conducted with a field portable visible near-infrared spectrometer for comparison to similar Martian data sets. Three classes of alteration minerals were identified: sulfates (gypsum and natroalunite), oxides/hydroxides (hematite and goethite), and phyllosilicates (kaolinite/halloysite, montmorillonite, and saponite), as well as elemental sulfur and hydrated silica phases. Our sites had similar suites of minerals, but frequencies varied with location. The results of this field campaign allow inferences regarding the paleo-environmental conditions that were likely present at similar relic hydrothermal sites identified on Mars. In particular, sulfates and phyllosilicates could have coevolved under hydrothermal conditions at Noctis Labyrinthus as is seen in Nicaragua. Fe/Mg smectites were detected in areas with pH of 3-4. Alunite spectra at Terra Sirenum demonstrated mineral mixing effects on spectroscopy. Mineral mixing can cause uncertainties in spectral identification due to a dominant spectrum, such as iron minerals, masking another or the suppression of weaker bands. When viewed from orbit, our field sites would likely be dominated by hydrated silica and Mars sites, such as one in Syrtis Major, could have a more diverse mineralogy than the data reveal. Concentrated amorphous silica, such as at Gusev crater, can result from acidic fumarolic activity, while Mg sulfates may indicate a lack of reworking by water. This field spectroscopy study helps confirm and provide insight into hydrothermal processes on ancient Mars.

  15. Sulfated hyaluronic acid hydrogels with retarded degradation and enhanced growth factor retention promote hMSC chondrogenesis and articular cartilage integrity with reduced hypertrophy.

    PubMed

    Feng, Qian; Lin, Sien; Zhang, Kunyu; Dong, Chaoqun; Wu, Tianyi; Huang, Heqin; Yan, Xiaohui; Zhang, Li; Li, Gang; Bian, Liming

    2017-02-11

    Recently, hyaluronic acid (HA) hydrogels have been extensively researched for delivering cells and drugs to repair damaged tissues, particularly articular cartilage. However, the in vivo degradation of HA is fast, thus limiting the clinical translation of HA hydrogels. Furthermore, HA cannot bind proteins with high affinity because of the lack of negatively charged sulfate groups. In this study, we conjugated tunable amount of sulfate groups to HA. The sulfated HA exhibits significantly slower degradation by hyaluronidase compared to the wild type HA. We hypothesize that the sulfation reduces the available HA octasaccharide substrate needed for the effective catalytic action of hyaluronidase. Moreover, the sulfated HA hydrogels significantly improve the protein sequestration, thereby effectively extending the availability of the proteinaceous drugs in the hydrogels. In the following in vitro study, we demonstrate that the HA hydrogel sulfation exerts no negative effect on the viability of encapsulated human mesenchymal stem cells (hMSCs). Furthermore, the sulfated HA hydrogels promote the chondrogenesis and suppresses the hypertrophy of encapsulated hMSCs both in vitro and in vivo. Moreover, intra-articular injections of the sulfated HA hydrogels avert the cartilage abrasion and hypertrophy in the animal osteoarthritic joints. Collectively, our findings demonstrate that the sulfated HA is a promising biomaterial for the delivery of therapeutic agents to aid the regeneration of injured or diseased tissues and organs.

  16. Acidic gases and nitrate and sulfate particles in the atmosphere in the city of Guadalajara, México.

    PubMed

    Saldarriaga-Noreña, Hugo; Waliszewski, Stefan; Murillo-Tovar, Mario; Hernández-Mena, Leonel; de la Garza-Rodríguez, Iliana; Colunga-Urbina, Edith; Cuevas-Ordaz, Rosalva

    2012-05-01

    Atmospheric concentrations of nitrous acid, nitric acid, nitrate and sulfate particles were obtained in this study from April to June 2008 in the center of the city of Guadalajara, while concentrations of ozone, sulfur dioxide, nitrogen dioxide and meteorological parameters (temperature and relative humidity), were acquired by the Secretaría del Medio Ambiente para el Desarrollo Sustentable del Estado de Jalisco (SEMADES). The results showed that nitric acid (2.7 μg m(-3)) was 2.7 times higher than nitrous acid (1.0 μg m(-3)). The sulfur dioxide (SO(2)) concentration indicated an opposite trend to sulfate (SO(4) (2-)), with the average concentration of SO(2) (6.9 μg m(-3)) higher in almost the entire period of study. The sulfur conversion ratio (Fs, 24.9%) and nitrogen conversion ratio (Fn, 6.2%), were revealed to be similar to that reported in other urban areas during warm seasons. It is also noted that ozone is not the main oxidizer of nitrogen dioxide and sulfur dioxide. This determination was made by taking into account the slightly positively correlation determined for Fn (r(2) = 0.084) and Fs (r(2) = 0.092) with ozone that perhaps suggests there are other oxidizing species such as the radical OH, which are playing an important role in the processes of atmospheric oxidation in this area.

  17. Nickel recovery from electronic waste II Electrodeposition of Ni and Ni–Fe alloys from diluted sulfate solutions

    SciTech Connect

    Robotin, B.; Ispas, A.; Coman, V.; Bund, A.; Ilea, P.

    2013-11-15

    Highlights: • Ni can be recovered from EG wastes as pure Ni or as Ni–Fe alloys. • The control of the experimental conditions gives a certain alloy composition. • Unusual deposits morphology shows different nucleation mechanisms for Ni vs Fe. • The nucleation mechanism was progressive for Ni and instantaneous for Fe and Ni–Fe. - Abstract: This study focuses on the electrodeposition of Ni and Ni–Fe alloys from synthetic solutions similar to those obtained by the dissolution of electron gun (an electrical component of cathode ray tubes) waste. The influence of various parameters (pH, electrolyte composition, Ni{sup 2+}/Fe{sup 2+} ratio, current density) on the electrodeposition process was investigated. Scanning electron microscopy (SEM) and X-ray fluorescence analysis (XRFA) were used to provide information about the obtained deposits’ thickness, morphology, and elemental composition. By controlling the experimental parameters, the composition of the Ni–Fe alloys can be tailored towards specific applications. Complementarily, the differences in the nucleation mechanisms for Ni, Fe and Ni–Fe deposition from sulfate solutions have been evaluated and discussed using cyclic voltammetry and potential step chronoamperometry. The obtained results suggest a progressive nucleation mechanism for Ni, while for Fe and Ni–Fe, the obtained data points are best fitted to an instantaneous nucleation model.

  18. Selective recognition of sulfate anions in a 95% ethanol solvent with a simple neutral salicylaldehyde dansyl hydrazine Schiff base tuned by Brønsted-Lowry acid-base reaction.

    PubMed

    Wei, Gao-Ning; Zhang, Jing-Li; Jia, Cang; Fan, Wei-Zhen; Lin, Li-Rong

    2014-07-15

    A new Schiff base compound, 5-(dimethylamino)-N'-(2-hydroxybenzylidene)naphthalene-1-sulfonohydrazide (R), has been synthesized, characterized, and employed as a selective fluorescence receptor for the recognition of sulfate anions. UV-vis absorption, fluorescence emission, (1)H NMR spectra and DFT calculation studies on the system have been carried out to determine the nature of the interactions between R and anions. The results reveal that the deprotonation of the phenol without the need of a strong base leads to the formation of a hydrogen-bonding complex with a -SO2-NH- group, which is responsible for the spectra changes. The deprotonation process for the selectivity recognition of sulfate can be tuned by the Brønsted-Lowry acid-base reaction in nonaqueous solutions, revealing that suitable phenolic hydroxyl acidity is the key factor for anion recognition selectivity.

  19. Selective recognition of sulfate anions in a 95% ethanol solvent with a simple neutral salicylaldehyde dansyl hydrazine Schiff base tuned by Brønsted-Lowry acid-base reaction

    NASA Astrophysics Data System (ADS)

    Wei, Gao-Ning; Zhang, Jing-Li; Jia, Cang; Fan, Wei-Zhen; Lin, Li-Rong

    2014-07-01

    A new Schiff base compound, 5-(dimethylamino)-N‧-(2-hydroxybenzylidene)naphthalene-1-sulfonohydrazide (R), has been synthesized, characterized, and employed as a selective fluorescence receptor for the recognition of sulfate anions. UV-vis absorption, fluorescence emission, 1H NMR spectra and DFT calculation studies on the system have been carried out to determine the nature of the interactions between R and anions. The results reveal that the deprotonation of the phenol without the need of a strong base leads to the formation of a hydrogen-bonding complex with a sbnd SO2sbnd NHsbnd group, which is responsible for the spectra changes. The deprotonation process for the selectivity recognition of sulfate can be tuned by the Brønsted-Lowry acid-base reaction in nonaqueous solutions, revealing that suitable phenolic hydroxyl acidity is the key factor for anion recognition selectivity.

  20. Coulometric determination of berkelium in sulfuric acid and nitric acid solutions

    SciTech Connect

    Timofeev, G.A.; Chistyakov, V.M.; Erin, E.A.

    1987-03-01

    Results are reported on the study and quantitative determination of berkelium by the coulometric method in 1 M sulfuric acid, in solutions of nitric acid, and in mixtures of these acids. The best results in the determination of berkelium were obtained in solutions of a mixture of nitric and sulfuric acids. In 1 M HNO/sub 3/ + 0.1 M H/sub 2/SO/sub 4/ solutions, berkelium can be determined with an accuracy within approx. +/- 2%, when its content is 10 ..mu..g/ml.

  1. RADIATION CHEMISTRY OF HIGH ENERGY CARBON, NEON AND ARGON IONS: INTEGRAL YIELDS FROM FERROUS SULFATE SOLUTIONS

    SciTech Connect

    Christman, E.A.; Appleby, A.; Jayko, M.

    1980-07-01

    Chemical yields of Fe{sup 3+} have been measured from FeSO{sub 4} solutions irradiated in the presence and absence of oxygen with carbon, neon, and argon ions from the Berkeley Bevalac facility. G(Fe{sup 3+}) decreases with increasing beam penetration and with increasing atomic number of the incident ion. The results are compared with current theoretical expectations of the behavior of these particles in an aqueous absorber. The chemical yields are consistently higher than theoretically predicted, by amounts varying from <6.2% (carbon ions) to <13.2% (argon ions). The additional yields are possibly attributable to fragmentation of the primary particle beams.

  2. Reactivity of Tannic Acid with Common Corrosion Products and Its Influence on the Hydrolysis of Iron in Alkaline Solutions

    NASA Astrophysics Data System (ADS)

    Jaén, J. A.; Araúz, E. Y.; Iglesias, J.; Delgado, Y.

    2003-06-01

    To ascertain the role of tannic acid in the anticorrosive protection of steels, the reaction between 5% tannic acid aqueous solutions with lepidocrocite, goethite, superparamagnetic goethite, akaganeite, poorly crystalline maghemite, magnetite and hematite was studied using color changes, infrared and Mössbauer spectroscopy. After three months of interaction with lepidocrocite, the formation of an iron tannate complex was detected by its dark blue color and confirmed by infrared and Mössbauer analysis. Evidence for the chemical transformation was obtained for goethite in nanoparticles and poorly crystalline maghemite after reaction for six months. The other iron compounds do not transform to another oxide or phase upon treatment with the tannic acid solution. These results showed that lepidocrocite is the most reactive phase and that the size and degree of crystallinity have strong influence on the formation of the tannate complexes. The precipitation of iron phases from alkaline solutions of iron (II) sulfate heptahydrate containing different amount of tannic acid and potassium nitrate as oxidative agent was also studied. Mössbauer and infrared results show that in the absence of tannic acid some common rust components are obtained (viz. goethite, superparamagnetic goethite, maghemite and non-stoichiometric magnetite). The presence of 0.1% tannic acid in a low alkalinity solution results in the precipitation of iron oxyhydroxides and some iron tannates. Concentrations of 1% tannic acid are required for the formation of the tannates complexes as main reaction product.

  3. Effectiveness of the bran media and bacteria inoculum treatments in increasing pH and reducing sulfur-total of acid sulfate soils

    NASA Astrophysics Data System (ADS)

    Taufieq, Nur Anny Suryaningsih; Rahim, Sahibin Abdul; Jamil, Habibah

    2013-11-01

    This study was carried out to determine the effectiveness ofsulfate reducing bacteria (SRB) in using bran as a source of food and energy, and to see the effectiveness of the bran media and bacteria inoculums treatments for pH and sulfur-total of acid sulfate reduction insoils. This study used two factors in group random designs with four treatments for bacteria inoculum of B1 (1%), B2 (5%), B3 (10%), B4 (15%) and two treatments for organic media (bran) of D1 (1:1) and D2 (1:19). Based on three replications, the combination resulted in a total of 24 treatments. Soil pH was measured using the Duddridge and Wainright method and determination of sulfate content in soil was conducted by the spectrophotometry method. The data obtained was analyzed for significance by Analysis of Variance and the Least Significant Difference Test. The pH of the initial acid sulfate soils ranged from 3 to 4 and the soil sulfur-total ranged from 1.4% to 10%. After mixing sulfate reducing bacteria with the bran mediaand incubated for four days, the pH of the acid sulfate soils increased from 3.67 to 4.20, while the soil sulfur-total contents had been reduced by 2.85% to 0.35%. This experiment has proven that an acid sulfate soil with low pH is a good growth medium for the sulfate reducing bacteria. The bestincubation period to achieve an effective bioremediation resultthrough sulfate percentage reduction by sulfate reducing bacteria was 10 days, while the optimum bran media dose was 1:19, and the bacteria inoculums dose was 10%.

  4. Measurement of chemical leaching potential of sulfate from landfill disposed sulfate containing wastes.

    PubMed

    Sun, Wenjie; Barlaz, Morton A

    2015-02-01

    A number of sulfate-containing wastes are disposed in municipal solid wastes (MSW) landfills including residues from coal, wood, and MSW combustion, and construction and demolition (C&D) waste. Under anaerobic conditions that dominate landfills, the sulfate can be reduced to hydrogen sulfide which is problematic for several reasons including its low odor threshold, toxicity, and corrosive nature. The overall objective of this study was to evaluate existing protocols for the quantification of total leachable sulfate from solid samples and to compare their effectiveness and efficiency with a new protocol described in this study. Methods compared include two existing acid extraction protocols commonly used in the U.S., a pH neutral protocol that requires multiple changes of the leaching solution, and a new acid extraction method. The new acid extraction method was shown to be simple and effective to measure the leaching potential of sulfate from a range of landfill disposed sulfate-containing wastes. However, the acid extraction methods do not distinguish between sulfate and other forms of sulfur and are thus most useful when sulfate is the only form of sulfur present.

  5. Population and size distribution of solute-rich mesospecies within mesostructured aqueous amino acid solutions.

    PubMed

    Jawor-Baczynska, Anna; Moore, Barry D; Lee, Han Seung; McCormick, Alon V; Sefcik, Jan

    2013-01-01

    Aqueous solutions of highly soluble substances such as small amino acids are usually assumed to be essentially homogenous systems with some degree of short range local structuring due to specific interactions on the sub-nanometre scale (e.g. molecular clusters, hydration shells), usually not exceeding several solute molecules. However, recent theoretical and experimental studies have indicated the presence of much larger supramolecular assemblies or mesospecies in solutions of small organic and inorganic molecules as well as proteins. We investigated both supersaturated and undersaturated aqueous solutions of two simple amino acids (glycine and DL-alanine) using Dynamic Light Scattering (DLS), Brownian Microscopy/Nanoparticles Tracking Analysis (NTA) and Cryogenic Transmission Electron Microscopy (Cryo-TEM). Colloidal scale mesospecies (nanodroplets) were previously reported in supersaturated solutions of these amino acids and were implicated as intermediate species on non-classical crystallization pathways. Surprisingly, we have found that the mesospecies are also present in significant numbers in undersaturated solutions even when the solute concentration is well below the solid-liquid equilibrium concentration (saturation limit). Thus, mesopecies can be observed with mean diameters ranging from 100 to 300 nm and a size distribution that broadens towards larger size with increasing solute concentration. We note that the mesospecies are not a separate phase and the system is better described as a thermodynamically stable mesostructured liquid containing solute-rich domains dispersed within bulk solute solution. At a given temperature, solute molecules in such a mesostructured liquid phase are subject to equilibrium distribution between solute-rich mesospecies and the surrounding bulk solution.

  6. Long term response of acid-sensitive Vermont Lakes to sulfate deposition

    EPA Science Inventory

    Atmospheric deposition of sulfur can negatively affect the health of lakes and streams, particularly in poorly buffered catchments. In response to the Clean Air Act Amendments, wet deposition of sulfate decreased more than 35% in Vermont between 1990 and 2008. However, most of ...

  7. Mapping Acid Sulfate Alteration of Basaltic Andesite with Thermal Infrared Data

    NASA Technical Reports Server (NTRS)

    Vaughan, R. G.; Calvin, W. M.; Hook, S. J.; Taranik, J. V.

    2002-01-01

    Airborne thermal infrared multi- and hyperspectral data sets are used to map sulfate alteration of basaltic andesites near Reno, NV. Alteration includes quartz-alunite, jarosite and a number of clay minerals such as kaolinite and montmorillonite. Additional information is contained in the original extended abstract.

  8. MICROBIAL SULFATE REDUCTION AND METAL ATTENUATION IN PH 4 ACID MINE WATER

    EPA Science Inventory

    Sediments recovered from the flooded mine workings of the Penn Mine, a Cu-Zn mine abandoned since the early 1960s, were cultured for anaerobic bacteria over a range of pH (4 to 7.5). The molecular biology of sediments and cultures was studied to determine whether sulfate-reducing...

  9. Interaction Between CO2-Rich Sulfate Solutions and Carbonate Reservoir Rocks from Atmospheric to Supercritical CO2 Conditions: Experiments and Modeling

    NASA Astrophysics Data System (ADS)

    Cama, J.; Garcia-Rios, M.; Luquot, L.; Soler Matamala, J. M.

    2014-12-01

    A test site for CO2 geological storage is situated in Hontomín (Spain) with a reservoir rock that is mainly composed of limestone. During and after CO2 injection, the resulting CO2-rich acid brine gives rise to the dissolution of carbonate minerals (calcite and dolomite) and gypsum (or anhydrite at depth) may precipitate since the reservoir brine contains sulfate. Experiments using columns filled with crushed limestone or dolostone were conducted under different P-pCO2 conditions (atmospheric: 1-10-3.5 bar; subcritical: 10-10 bar; and supercritical: 150-34 bar), T (25, 40 and 60 ºC) and input solution compositions (gypsum-undersaturated and gypsum-equilibrated solutions). We evaluated the effect of these parameters on the coupled reactions of calcite/dolomite dissolution and gypsum/anhydrite precipitation. The CrunchFlow and PhreeqC (v.3) numerical codes were used to perform reactive transport simulations of the experiments. Under the P-pCO2-T conditions, the volume of precipitated gypsum was smaller than the volume of dissolved carbonate minerals, yielding an increase in porosity (Δporosity up to ≈ 4%). A decrease in T favored limestone dissolution regardless of pCO2 owing to increasing undersaturation with decreasing temperature. However, gypsum precipitation was favored at high T and under atmospheric pCO2 conditions but not at high T and under 10 bar of pCO2 conditions. The increase in limestone dissolution with pCO2 was directly attributed to pH, which was more acidic at higher pCO2. Increasing pCO2, carbonate dissolution occurred along the column whereas it was localized in the very inlet under atmospheric conditions. This was due to the buffer capacity of the carbonic acid, which maintains pH at around 5 and keeps the solution undersaturated with respect to calcite and dolomite along the column. 1D reactive transport simulations reproduced the experimental data (carbonate dissolution and gypsum precipitation for different P-pCO2-T conditions). Drawing

  10. Electron spin echo modulation study of sodium dodecyl sulfate and dodecyltrimethylammonium bromide micellar solutions in the presence of urea: Evidence for urea interaction at the micellar surface

    SciTech Connect

    Baglioni, P. ); Ferroni, E. ); Kevan, L. )

    1990-05-17

    Electron spin echo studies have been carried out for a series of x-doxylstearic acid (x-DSA, x = 5,7,10,12,16) and 4-octanoyl-2,2,6,6-tetramethylpiperidine-1-oxy (C{sub 8}-TEMPO) spin probes in micellar solutions of anionic sodium dodecyl sulfate (SDS) and cationic dodecyltrimethylammonium bromide (DTAB) in D{sub 2}O and in the presence of 2 or 6 M urea or urea-d{sub 4}. Modulation effects due to the interaction of the unpaired electron with urea and water deuteriums show that urea does not affect the bent conformation of the x-DSA probe in the micelle. The analysis of the deuterium modulation depth and the Fourier transformation of the two-pulse electron spin echo spectra show that urea interacts with the surfactant polar headgroups at the micelle surface. These results support recent molecular dynamics and Monte Carlo calculations of micellar systems and are in agreement with direct interaction of urea at micellar surfaces in which it replaces some water molecules in the surface region.

  11. Solubility of HOBr in Acidic Solution and Implications for Liberation of Halogens Via Aerosol Processing

    NASA Technical Reports Server (NTRS)

    Iraci, Laura T.; Michelsen, R. R.; Rammer, T. A.; Ashbourn, S. F. M.

    2004-01-01

    Halogen species are known to catalytically destroy ozone in several regions of the atmosphere. In addition to direct catalytic losses, bromine compounds can indirectly enhance ozone loss through coupling to other radical families. Hypobromous acid (HOBr) is a key species in the linkage of BrOx to ClOx and HOx. The aqueous- phase coupling reaction HOBr + HCI (right arrow) BrCl + H2O may provide a pathway for chlorine activation on sulfate aerosols at temperatures warmer than those required for polar stratospheric cloud formation. We have measured t h e solubility of HOBr in 45 - 70 wt% sulfuric acid solutions. Over the temperature range 201 - 252 K, HOBr is quite soluble in sulfuric acid, H* = 10(exp 4) - 10(exp 7) mol dm(exp -3) atm(exp -1). The expected inverse dependence of H* on temperature was observed, but only a weak dependence on acidity was found. The solubility of HOBr is comparable to that of HBr, indicating that equilibrium concentrations of HOBr could equal or exceed those of HBr in upper tropospheric and lower stratospheric aerosols. Despite the high solubility of HOBr, aerosol volumes are not large enough to sequester a significant fraction of inorganic bromine from the gas phase. Our measurements of HOBr uptake in aqueous sulfuric acid in the presence of other brominated gases show the evolution of gaseous products including Br2O and Br2.

  12. Separation of hafnium from zirconium in sulfuric acid solutions using pressurized ion exchange

    SciTech Connect

    Hurst, F.J.

    1981-01-01

    High-resolution pressurized ion exchange has been used successfully to study and separate hafnium and zirconium sulfate complexes by chromatographic elution from Dowex 50W-X8 (15 to 25 ..mu..m) resin with sulfuric acid solutions. Techniques were developed to continuously monitor the column effluents for zirconium and hafnium by reaction with fluorometric and colorimetric reagents. Since neither reagent was specific for either metal ion, peak patterns were initially identified by using the stable isotopes /sup 90/Zr and /sup 180/Hf as fingerprints of their elution position. Distribution ratios for both zirconium and hafnium decrease as the inverse fourth power of the sulfuric acid concentration below 2N and as the inverse second power at higher acid concentration. The hafnium-to-zirconium separation factor is approximately constant (approx. 8) over the 0.5 to 3N range. Under certain conditions, an unseparated fraction was observed that was not retained by the resin. The amount of this fraction which is thought to be a polymeric hydrolysis product appears to be a function of metal and sulfuric acid concentrations. Conditions are being sought to give the highest zirconium concentration and the lowest acid concentration that can be used as a feed material for commercial scale-up in the continuous annular chromatographic (CAC) unit without formation of the polymer.

  13. Assignment Of Hexuronic Acid Stereochemistry In Synthetic Heparan Sulfate Tetrasaccharides With 2-O-Sulfo Uronic Acids Using Electron Detachment Dissociation.

    PubMed

    Agyekum, Isaac; Patel, Anish B; Zong, Chengli; Boons, Geert-Jan; Amster, Jonathan

    2015-11-15

    The present work focuses on the assignment of uronic acid stereochemistry in heparan sulfate (HS) oligomers. The structural elucidation of HS glycosaminoglycans is the subject of considerable importance due to the biological and biomedical significance of this class of carbohydrates. They are highly heterogeneous due to their non-template biosynthesis. Advances in tandem mass spectrometry activation methods, particularly electron detachment dissociation (EDD), has led to the development of methods to assign sites of sulfo modification in glycosaminoglycan oligomers, but there are few reports of the assignment of uronic acid stereochemistry, necessary to distinguish glucuronic acid (GlcA) from iduronic acid (IdoA). Whereas preceding studies focused on uronic acid epimers with no sulfo modification, the current work extends the assignment of the hexuronic acid stereochemistry to 2-O-sulfo uronic acid epimeric tetrasaccharides. The presence of a 2-O-sulfo group on the central uronic acid was found to greatly influence the formation of B3, C2, Z2, and Y1 ions in glucuronic acid and Y2 and (1,5)X2 for iduronic acid. The intensity of these peaks can be combined to yield a diagnostic ratios (DR), which can be used to confidently assign the uronic acid stereochemistry.

  14. Reactive trace element enrichment in a highly modified, tidally inundated acid sulfate soil wetland: East Trinity, Australia.

    PubMed

    Keene, Annabelle F; Johnston, Scott G; Bush, Richard T; Burton, Edward D; Sullivan, Leigh A

    2010-04-01

    This study examines the abundance of trace elements in surface sediments of a former acid sulfate soil (ASS) wetland subjected to marine tidal inundation. Sediment properties of this highly modified study site are compared with those of an adjacent unmodified, intertidal mangrove forest. Whilst some trace elements (Al, Cd, Mn, Ni and Zn) were clearly depleted due to mobilisation and leaching in the previous oxic-acidic phase, other trace elements (As and Cr) displayed significant enrichment in the tidally inundated ASS. Many trace elements were strongly associated with the reactive Fe and acid volatile sulfide (AVS) fractions, suggesting that trace elements may be adsorbed to abundant reactive Fe phases or sequestered as sulfide minerals. These findings provide an important understanding of the fate and mobility of reactive iron, AVS and trace elements during tidal remediation of a formerly acidified Great Barrier Reef (GBR) catchment.

  15. Dephosphorization of Steelmaking Slag by Leaching with Acidic Aqueous Solution

    NASA Astrophysics Data System (ADS)

    Qiao, Yong; Diao, Jiang; Liu, Xuan; Li, Xiaosa; Zhang, Tao; Xie, Bing

    2016-09-01

    In the present paper, dephosphorization of steelmaking slag by leaching with acidic aqueous solution composed of citric acid, sodium hydroxide, hydrochloric acid and ion-exchanged water was investigated. The buffer solution of C6H8O7-NaOH-HCl system prevented changes in the pH values. Kinetic parameters including leaching temperature, slag particle size and pH values of the solution were optimized. The results showed that temperature has no obvious effect on the dissolution ratio of phosphorus. However, it has a significant effect on the dissolution ratio of iron. The dephosphorization rate increases with the decrease of slag particle size and the pH value of the solution. Over 90% of the phosphorus can be dissolved in the solution while the corresponding leaching ratio of iron was only 30% below the optimal condition. Leaching kinetics of dephosphorization follow the unreacted shrinking core model with a rate controlled step by the solid diffusion layer, the corresponding apparent activation energy being 1.233 kJ mol-1. A semiempirical kinetic equation was established. After leaching, most of the nC2S-C3P solid solution in the steelmaking slag was selectively dissolved in the aqueous solution and the iron content in the solid residue was correspondingly enriched.

  16. Acidity variations across the cloud drop size spectrum and their influence on rates of atmospheric sulfate production

    SciTech Connect

    Collett, J.L. Jr.; Bator, A.; Rao, Xin; Demoz, B.

    1994-11-01

    Measurements of pH variations within natural cloud drop populations reveal that small drops are often more acidic than large drops. Cloud samples collected from coastal stratus clouds, frontal clouds, and radiation fogs, from heavily polluted and pristine locations, had pH values ranging from below three to more than seven. Differences between small and large cloud drop acidities as large as two pH units were observed, although differences were generally below one pH unit. This chemical heterogenity can significantly enhance oxidation of sulfur dioxide to sulfate within clouds, relative to oxidation rates predicted from the average cloudwater composition. One-third of the sampled clouds were estimated to experience an increase of at least 20% in the rate of sulfur oxidation by ozone (8% of the clouds had increases exceeding 100%) as a result of acidity differences between large and small cloud drops. These findings suggest that sulfate production within clouds, a critical component of the global sulfur cycle, may be more rapid than previously though. 20 refs., 3 figs.

  17. Toxicology of cupric salts on honeybees. V. Gluconate and sulfate action on gut alkaline and acid phosphatases.

    PubMed

    Bounias, M; Kruk, I; Nectoux, M; Popeskovic, D

    1996-10-01

    Some aspects of putative nontarget effects of cupric ions systemically fed to honeybees against their parasite mite Varroa jacobsoni have been investigated on the host phosphatases. The alkaline and acid forms extracted from the guts of worker bees exhibited substrate-inhibition features. Upon detailed kinetic analysis, cupric organic salts indicate activation effects at concentrations of about 1 mM. Concentrations up to 10 mM (alkaline form) and 25 mM (acid form) induced no important changes, except a partial quenching of the substrate-inhibition process, characterized by a wide increase in the constant of apparent inhibitory binding of substrate to the enzyme-substrate complex. Partial purification gave a single alkaline form with quite similar kinetic behavior in the absence of natural ions as in crude extracts. Cupric gluconate and sulfate demonstrated similar patterns, except an increase of the apparent Hill coefficient by sulfate only. The substrate constant of acid phosphatases was decreased at high cupric gluconate doses while its maximum velocity was biphasically increased (with observed maximum at 1 mM), resulting in a sustained activation. Chemiluminescence studies revealed that cupric ion activation is counteracted by oxygen radicals generated by cupric ions and also, in vitro, by the artificial substrate para-nitrophenylphosphate. The para-nitrophenol molecules released from the reaction are therefore responsible for biphasic effects selectively observed with gluconate salts. In apicultural practice, neither blockade of activity nor dramatic changes are to be expected at doses administered to bees against the parasite.

  18. Coprecipitation of thorium and uranium peroxides from acid solutions

    SciTech Connect

    McTaggart, D.R.; Mailen, J.C.

    1981-01-01

    The factors affecting successful coprecipitation of thorium and uranium peroxides from acid media were studied. Variables considered in this work were H/sup +/ concentration, H/sub 2/O/sub 2/ concentration, duration of contact, and rate of feed solution addition. In all experiments, stock solutions of Th(NO/sub 3/)/sub 4/ and UO/sub 2/(NO/sub 3/)/sub 2/ were fed at a controlled rate into H/sub 2/O/sub 2/ solutions with constant stirring. Samples were taken as a function of time to follow the H/sup +/ concentration of the solution, uranium precipitation, thorium precipitation, precipitant weight/volume of solution, and crystalline structure and growth. The optimum conditions for maximum coprecipitation are low H/sup +/ concentration, high H/sub 2/O/sub 2/ concentration, and extended contact time between the solutions.

  19. Recovery of H2SO4 from an acid leach solution by diffusion dialysis.

    PubMed

    Wei, Chang; Li, Xingbin; Deng, Zhigan; Fan, Gang; Li, Minting; Li, Cunxiong

    2010-04-15

    Diffusion dialysis with a series of anion exchange membranes was used to recover H(2)SO(4) from an acid leach solution produced during the vanadium manufacturing process. The effects of sulfuric acid, FeSO(4) and VOSO(4) concentration, flow rate and flow rate ratio on the recovery of H(2)SO(4) were investigated. The results showed that sulfuric acid permeated well through the membranes used, while metal ions were efficiently rejected. The recovery of H(2)SO(4) increased as the sulfate concentration of the feed increased and the flow rate ratio of water to feed increased. More than 80% of the H(2)SO(4) could be recovered from the leach solution which contained 61.7 g/L free H(2)SO(4), 11.2 g/L Fe and 4.60 g/L V at a flow rate of 0.19x10(-3) m(3)/h m(2). V and Fe ion rejection were within 93-95 and 92-94%, respectively. A preliminary economic evaluation revealed that an investment in this process could be recovered within 27 months.

  20. γ-Irradiation of malic acid in aqueous solutions

    NASA Astrophysics Data System (ADS)

    Negron-Mendoza, Alicia; Graff, Rebecca L.; Ponnamperuma, Cyril

    1980-12-01

    The γ-irradiation of malic acid in aqueous solutions was studied under initially oxygenated and oxygen-free conditions in an attempt to determine the possible interconversion of malic acid into other carboxylic acids, specifically those associated with Krebs cycle. The effect of dose on product formation of the system was investigated. Gas-liquid chromatography combined with mass spectrometry was used as the principal means of identification of the non-volatile products. Thin layer chromotography and direct probe mass spectroscopy were also employed. The findings show that a variety of carboxylic acids are formed, with malonic and succinic acids in greatest abundance. These products have all been identified as being formed in the γ-irradiation of acetic acid, suggesting a common intermediary. Since these molecules fit into a metabolic cycle, it is strongly suggestive that prebiotic pathways provided the basis for biological systems.

  1. Diffusion-controlled evaporation of sodium dodecyl sulfate solution drops placed on a hydrophobic substrate.

    PubMed

    Doganci, Merve Dandan; Sesli, Belma Uyar; Erbil, H Yildirim

    2011-10-15

    In this work, the effect of SDS anionic surfactant on the diffusion-controlled evaporation rate of aqueous solution drops placed on TEFLON-FEP substrate was investigated with 11 different SDS concentrations. Drop evaporation was monitored in a closed chamber having a constant RH of 54-57% by a video camera. The initial contact angle, θ(i) decreased from 104±2° down to 68±1° due to the adsorption of SDS both at the water-air and the solid-water interfaces. The adsorption of SDS on the solid surface was found to be 76% of that of its adsorption at the water-air interface by applying Lucassen-Reynders approach. An equation was developed for the comparison of the evaporation rates of drops having different θ(i) on the same substrate. It was found that the addition of SDS did not alter the drop evaporation rate considerably for the first 1200 s for all the SDS concentrations. The main difference was found to be the change of the mode of drop evaporation by varying the SDS concentration. The constant θ mode was operative up to 80 mM SDS concentration, whereas constant contact area mode was operative after 200 mM SDS concentrations due to rapid drop pining on the substrate.

  2. A spectrophotometric study of Nd(III), Sm(III) and Er(III) complexation in sulfate-bearing solutions at elevated temperatures

    NASA Astrophysics Data System (ADS)

    Migdisov, Art. A.; Williams-Jones, A. E.

    2008-11-01

    The speciation of Nd(III), Sm(III), and Er(III) in sulfate-bearing solutions has been determined spectrophotometrically at temperatures from 25 to 250 °C and a pressure of 100 bars. The data obtained earlier on the speciation of Nd in sulfate-bearing solutions ( Migdisov et al., 2006) have been re-evaluated and corrected using a more appropriate activity model and are compared with the corresponding data for Sm(III) and Er(III) and new data for Nd(III). Based on this comparison, the dominant species in the solution are interpreted to be REESO4+ and REE(SO)2-, with the latter complex increasing in importance at higher temperature. Equilibrium constants were calculated for the following reactions:

  3. Highly accurate boronimeter assay of concentrated boric acid solutions

    SciTech Connect

    Ball, R.M. )

    1992-01-01

    The Random-Walk Boronimeter has successfully been used as an on-line indicator of boric acid concentration in an operating commercial pressurized water reactor. The principle has been adapted for measurement of discrete samples to high accuracy and to concentrations up to 6000 ppm natural boron in light water. Boric acid concentration in an aqueous solution is a necessary measurement in many nuclear power plants, particularly those that use boric acid dissolved in the reactor coolant as a reactivity control system. Other nuclear plants use a high-concentration boric acid solution as a backup shutdown system. Such a shutdown system depends on rapid injection of the solution and frequent surveillance of the fluid to ensure the presence of the neutron absorber. The two methods typically used to measure boric acid are the chemical and the physical methods. The chemical method uses titration to determine the ionic concentration of the BO[sub 3] ions and infers the boron concentration. The physical method uses the attenuation of neutrons by the solution and infers the boron concentration from the neutron absorption properties. This paper describes the Random-Walk Boronimeter configured to measure discrete samples to high accuracy and high concentration.

  4. Polymerization of Pu(IV) in aqueous nitric acid solutions

    SciTech Connect

    Toth, L.M.; Friedman, H.A.; Osborne, M.M.

    1980-10-01

    The polymerization of Pu(IV) in aqueous nitric acid solutions has been studied spectrophotometrically both to establish the influence of large UO{sub 2}(NO{sub 3}){sub 2} concentrations on the polymerization rates and, more generally, to review the influence of the major parameters on the polymer reaction. Typically, experiments have been performed at 50{sup 0}C and with 0.05 M Pu in nitric acid solutions that vary in acidity from 0.07 to 0.4 M. An induction period usually precedes the polymer growth stage during which time nucleation of primary hydrolysis products occurs. Uranyl nitrate retards the polymerization reaction by approximately 35% in spite of the counteracting influence of the nitrate ions associated with this solute. The rate of polymer formation, expressed as d(percent polymer)/dt, has been shown to depend on the total plutonium concentration in reactions where the Pu(IV) concentration remained constant; and it is therefore suggested that the polymer reaction rate is not first order with respect to the concentration of plutonium as was previously thought. It has been shown further that accurate acid determinations on stock reagents are essential in order to obtain reliable polymerization experiments. Satisfactory procedures for these analyses did not exist, so appropriate modifications to the iodate precipitation methods were developed. The most ideal plutonium reagent material has been shown to be crystalline Pu(IV) nitrate because it can be added directly to acid solutions without the occurrence of unintentional hydrolysis reactions.

  5. [Sorption of amino acids from aqueous solutions on activated charcoal].

    PubMed

    Nekliudov, A D; Tsibanov, V V

    1985-03-01

    Various methods for quantitative description of amino acid sorption from solutions for parenteral nutrition on activated charcoal were studied under dynamic and static conditions. With the use of the well-known Freindlich and Langmuir absorption isotherms it was shown to be possible to describe in a simplified way the complex multicomponent process of sorption of the amino acids and to estimate their loss at the filtration stage.

  6. Origin of salt additive effect on solute partitioning in aqueous polyethylene glycol-8000-sodium sulfate two-phase system.

    PubMed

    da Silva, Nuno R; Ferreira, Luisa A; Mikheeva, Larissa M; Teixeira, José A; Zaslavsky, Boris Y

    2014-04-11

    Partitioning of a homologous series of dinitrophenylted (DNP-) amino acids with aliphatic side chains was examined in aqueous polyethylene glycol (PEG)-8000-sodium sulfate two-phase systems (ATPS) with the additives NaSCN, NaClO4, and NaH2PO4 at concentrations varied from 0.025M up to 0.54M. The differences between the relative hydrophobicities and electrostatic properties of the two phases in all ATPS were estimated. Partitioning of adenine, adenosine mono-, di- and tri-phosphates was also examined in all ATPSs, including those with NaCl additive. Partition coefficients for these compounds and for nonionic organic compounds previously reported [L.A. Ferreira, P. Parpot, J.A. Teixeira, L.M. Mikheeva, B.Y. Zaslavsky, J. Chromatogr. A 1220 (2012) 14.] were analyzed in terms of linear solvent regression relationship. The results obtained suggest that the effects of the salts additives are related to their influence on the water structure.

  7. Development and validation of a stability indicating RP-HPLC method for the simultaneous determination of related substances of albuterol sulfate and ipratropium bromide in nasal solution.

    PubMed

    Kasawar, Gajanan B; Farooqui, Mazahar

    2010-05-01

    A simple, sensitive and specific RP-HPLC method was developed for the quantification of related impurities of albuterol sulfate (AS) and ipratropium bromide (IB) in liquid pharmaceutical dosage form. The chromatographic separation employs gradient elution using an inertsil C8-3, 250mmx4.6mm, 5mum columns. Mobile phase consisting of solvent A (solution containing 2.5g of potassium dihydrogen phosphate and 2.87g of heptane-1-sulfonic acid sodium salt per liter of water, adjusted to pH 4 with orthophosphoric acid) and solvent B (acetonitrile) delivered at a flow rate of 1.0mlmin(-1). The analytes were detected and quantified at 210nm using photodiode array (PDA) detector. The method was validated as per ICH guidelines, demonstrating to be accurate and precise (repeatability and intermediate precision level) within the corresponding linear range of known impurities of AS and IB. The specificity of the method was investigated under different stress conditions including hydrolytic, oxidative, photolytic and thermal as recommended by ICH guidelines. Relevant degradation was found to take place under hydrolytic and oxidative conditions. Robustness against small modification in pH, column oven temperature, flow rate and percentage of the mobile phase composition was ascertained. Lower limit of quantification and detection were also determined. The peak purity indices (purity angle

  8. Effect of a tea tree oil and organic acid footbath solution on digital dermatitis in dairy cows.

    PubMed

    Smith, A C; Wood, C L; McQuerry, K J; Bewley, J M

    2014-01-01

    Copper sulfate is the industry gold standard footbath ingredient for controlling dairy cow digital dermatitis. However, when used footbath solutions are deposited on soil, high levels of copper in the soil may result, which can have toxic and negative effects on plant growth. An alternative to copper sulfate is Provita Hoofsure Endurance (Provita Eurotech Ltd., Omagh, UK), which is a biodegradable solution containing organic acids, tea tree oil, and wetting agents. The objective of this study was to quantify changes in digital dermatitis frequency when using Provita Hoofsure Endurance and copper sulfate in a split footbath in 3 commercial dairy herds. This study was conducted from January 5, 2012, to March 19, 2012, in 3 commercial Kentucky dairies with 120, 170, and 200 milking Holstein cows. None of the herds was using a footbath for digital dermatitis control before the study. Footbath solutions were delivered using a split footbath. During the study, a 3% Hoofsure Endurance solution for the left hooves and a 5% copper sulfate solution for the right hooves was used. Digital dermatitis was scored every 3wk using the M0 to M4 system, where M0=a claw free of signs of digital dermatitis; M1=a lesion <2cm that is not painful; M2=the ulcerative stage, with lesion diameter of >2cm, and painful to the touch; M3=the healing stage and covered by a scab; and M4=the chronic stage and characterized by dyskeratosis or proliferation of the surface that is generally not painful. McNemar's test statistic suggested that a statistically significant difference existed in the proportions of M1 and M2 lesions between the beginning and end of the study for both treatments. This indicates that each solution was effective in decreasing the proportion of M1 or M2 lesions from baseline to the last time point. A chi-square test calculated using PROC FREQUENCY of SAS (SAS Institute Inc., Cary, NC) indicated that no statistically significant relationship existed between the treatments among

  9. Chemical and Mineralogical Characterization of Acid-Sulfate Alteration of Basaltic Material on Mauna Kea Volcano, Hawaii: Jarosite and Hydrated Halloysite

    NASA Technical Reports Server (NTRS)

    Graff, Trevor G.; Morris, R. V.; Archilles C. N.; Agresti, D. G.; Ming, D. W.; Hamilton, J. C.; Mertzman, S. A.; Smith, J.

    2012-01-01

    Sulfates have been identified on the martian surface during robotic surface exploration and by orbital remote sensing. Measurements at Meridiani Planum (MP) by the Alpha-Particle X-ray Spectrometer (APXS) and Mossbauer (MB) instruments on the Mars Exploration Rover Opportunity document the presence of a ubiquitous sulfate-rich outcrop (20-40% SO3) that has jarosite as an anhydrous Fe3+-sulfate [1- 3]. The presence of jarosite implies a highly acidic (pH <3) formation environment [4]. Jarosite and other sulfate minerals, including kieserite, gypsum, and alunite have also been identified in several locations in orbital remote sensing data from the MEx OMEGA and MRO CRISM instruments [e.g. 5-8]. Acid sulfate weathering of basaltic materials is an obvious pathway for formation of sulfate-bearing phases on Mars [e.g. 4, 9, 10]. In order to constrain acid-sulfate pathways on Mars, we are studying the mineralogical and chemical manifestations of acid-sulfate alteration of basaltic compositions in terrestrial environments. We have previously shown that acidsulfate alteration of tephra under hydrothermal conditions on the Puu Poliahu cone (summit region of Mauna Kea volcano, Hawaii) resulted in jarosite and alunite as sulfate-bearing alteration products [11-14]. Other, more soluble, sulfates may have formed, but were leached away by rain and melting snow. Acidsulfate processes on Puu Poliahu also formed hematite spherules similar (except in size) to the hematite spherules observed at MP as an alteration product [14]. Phyllosilicates, usually smectite }minor kaolinite are also present as alteration products [13]. We discuss here an occurrence of acid-sulfate alteration on Mauna Kea Volcano (Hawaii). We report VNIR spectra (0.35-2.5 microns ASD spectrometer), Mossbauer spectra (MER-like ESPI backscatter spectrometer), powder XRD (PANalytical), and major element chemical compositions (XRF with LOI and Fe redox) for comparison to similar data acquired or to be acquired by MRO

  10. Sulfated nanozirconia: an investigation on acid-base properties and n-butane isomerization activity.

    PubMed

    Mishra, H K; Dalai, A K; Das, D D; Parida, K M; Pradhan, N C

    2004-04-15

    Hydrated zirconia was synthesized by an organo-inorganic route employing surfactant and was sulfated using aqueous ammonium persulfate, followed by drying at 110 degrees C. The sample thus obtained was calcined at 600 degrees C to obtain sulfated zirconia and was characterized by several physicochemical methods. Crystallite sizes of sulfated zirconia were calculated from X-ray line broadening using the Debye-Scherer equation and were found to be in the range of 25 nm. When pretreated in air, the catalyst was found to exhibit butane isomerization activity at a temperature as low as 35 degrees C under atmospheric pressure. It showed conversion as high as 37% at 100 degrees C under normal pressure when pretreated in air, whereas nitrogen-pretreated catalyst showed zero activity under similar conditions. NH(3) and CO(2) temperature-programmed desorption studies on air- and helium-pretreated samples indicated that the catalyst surface changes appreciably during air pretreatment. Results on butane isomerization in conjunction with TPD studies suggest that zirconium-oxy sites play an important role in butane activation during the reaction.

  11. Effects of particle size and acid addition on the remediation of chromite ore processing residue using ferrous sulfate.

    PubMed

    Jagupilla, Santhi Chandra; Moon, Deok Hyun; Wazne, Mahmoud; Christodoulatos, Christos; Kim, Min Gyu

    2009-08-30

    A bench-scale treatability study was conducted to assess the effects of particle size and acid addition on the remediation of chromite ore processing residue (COPR) using ferrous sulfate. The remediation scheme entailed the chemical reduction of hexavalent chromium [Cr(VI)] and the mitigation of swell potential. Leaching tests and the EQ3/6 geochemical model were used to estimate the acid dosage required to destabilize Cr(VI)-bearing and swell-causing minerals. The model predicted greater acid dosage than that estimated from the batch leaching tests. This indicated that mass transfer limitation may be playing a significant role in impeding the dissolution of COPR minerals following acid addition and hence hindering the remediation of COPR. Cr(VI) concentrations determined by alkaline digestion for the treated samples were less than the current NJDEP standard. However, Cr(VI) concentrations measured by X-ray absorption near edge structure (XANES) were greater than those measured by alkaline digestion. Greater Cr(VI) percentages were reduced for acid pretreated and also for smaller particle size COPR samples. Upon treatment, brownmillerite content was greatly reduced for the acid pretreated samples. Conversely, ettringite, a swell-causing mineral, was not observed in the treated COPR.

  12. Synthesis and characterization of sulfated TiO2 nanorods and ZrO2/TiO2 nanocomposites for the esterification of biobased organic acid.

    PubMed

    Li, Zhonglai; Wnetrzak, Renata; Kwapinski, Witold; Leahy, James J

    2012-09-26

    TiO(2) nanorods and ZrO(2)-modified TiO(2) nanocomposites have been prepared by hydrothermal synthesis and the deposition-precipitation method. Their sulfated products were tested as solid superacid catalysts for the esterification of levulinic acid which was used as a model bio-oil molecule. SEM and TEM characterization showed that TiO(2) nanorods with diameters ranging from 20 to 200 nm and with lengths of up to 5 μm were synthesized by a hydrothermal method at 180 °C. ZrO(2) nanoparticles with the diameters ranging from 10 to 20 nm were evenly deposited on TiO(2) nanorods. IR and XPS results suggested that sulfated ZrO(2)/TiO(2) nanocomposite has higher content of sulfate groups on the surface with a S/(Zr+Ti) ratio of 13.6% than sulfated TiO(2) nanorods with a S/Ti ratio of 4.9%. The HPLC results showed that sulfated ZrO(2)/TiO(2) nanocomposite have enhanced catalytic activity for esterification reaction between levulinic acid and ethanol compared to sulfated TiO(2) nanorods. The conversion of levulinic acid to ethyl levulinate can reach to 90.4% at the reaction temperature of 105 °C after 180 min.

  13. Removal of fluoride in aqueous solution by adsorption on acid activated water treatment sludge

    NASA Astrophysics Data System (ADS)

    Vinitnantharat, Soydoa; Kositchaiyong, Sriwilai; Chiarakorn, Siriluk

    2010-06-01

    This paper reports the use of a pellet of adsorbent made from water treatment sludge (S) and acid activated water treatment sludge (SH) for removal of fluoride in the batch equilibration technique. The influence of pH, adsorbent dosage, temperature and effect of other ions were employed to find out the feasibility of acid activated adsorbent to remove fluoride to the permissible concentration of 0.7 mg/L. The results from the adsorption isotherm followed both Langmuir and Freundlich models and the highest fluoride removal was found for adsorbent activated with acetic acid at 2.0 mol/L. The optimum adsorbent dosage was found at 40 g/L, 0.01 mol/L acid activated adsorbent which was able to adsorb fluoride from 10 down to 0.11 mg/L. The adsorption capacity was decreased when the temperature increased. This revealed that the adsorption of fluoride on SH was exothermic. In the presence of nitrate and carbonate ions in the aqueous solution, fluoride removal efficiency of SH decreased from 94.4% to 86.6% and 90.8%, respectively. However, there is no significant effect in the presence of sulfate and chloride ions.

  14. Cocoa shells for heavy metal removal from acidic solutions.

    PubMed

    Meunier, N; Laroulandie, J; Blais, J F; Tyagi, R D

    2003-12-01

    The development of economic and efficient processes for the removal of heavy metals present in acidic effluents from industrial sources or decontamination technologies has become a priority. The purpose of this work was to study the efficiency with which cocoa shells remove heavy metals from acidic solutions (pH 2) and to investigate how the composition of these solutions influences heavy metal uptake efficiency. Adsorption tests were conducted in agitated flasks with single-metal solutions (0.25 mM Al, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn), multi-metal solution (comprised of 0.25 mM of each of the cations above) and an effluent obtained from chemical leaching of metal-contaminated soil, in the presence of different cocoa shell concentrations (5-40 g/l). Results from the single-metal solution assays indicated that the fixation capacity of heavy metals by cocoa shells followed a specific order: Pb>Cr>Cd=Cu=Fe>Zn=Co>Mn=Ni=Al. Cocoa shells are particularly efficient in the removal of lead from very acidic solutions (q(max)=6.2 mg Pb/g, pH(i)=2.0 and T=22 degrees C). The presence of other metals and cations in solution did not seem to affect the recovery of lead. It was also observed that the maximum metal uptake was reached in less than 2 h. This research has also demonstrated that the removal of metals caused a decline in solution proton concentration (pH increase) and release of calcium, magnesium, potassium and sodium from the cocoa shells.

  15. [Investigation on mechanism of pyrite oxidation in acidic solutions].

    PubMed

    Wang, Nan; Yi, Xiao-Yun; Dang, Zhi; Liu, Yun

    2012-11-01

    The mechanism of pyrite oxidation in acidic solutions was investigated by electrochemical analysis methods, such as open-circuit potential, cyclic voltammetry, Tafel polarization curve and anodic polarization curve, using a pyrite-carbon paste electrode as working electrode. The results showed that the oxidation process of pyrite in acidic solutions was via a two-step reaction: the first step was the dissolution of iron moiety and formation of a passivation film composed of elemental sulphur, metal-deficient sulfide and polysulfide; the second step was the further oxidation of these intermediate products to SO4(2-). The final reaction products of pyrite oxidation were Fe3+ and SO4(2-) in acidic solutions. In addition, the open-circuit potential and corrosion potential were positively shifted, the peak current and the corrosion current were increased with the increase in concentration of H2SO4 solutions. This indicated that increased acidity of the system was advantageous to the oxidation of pyrite.

  16. Polymeric Sulfated Amino Acid Surfactants: A New Class of Versatile Chiral Selectors for Micellar Electrokinetic Chromatography (MEKC) and MEKC-MS

    PubMed Central

    Ali Rizvi, Syed Asad; Zheng, Jie; Apkarian, Robert P.; Dublin, Steven N.; Shamsi, Shahab A.

    2008-01-01

    In this work, three amino acids derived (L-leucinol, L-isoleucinol and L-valinol) sulfated chiral surfactants are synthesized and polymerized. These chiral sulfated surfactants are thoroughly characterized to determine critical micelle concentration, aggregation number, polarity, optical rotation and partial specific volume. For the first time the morphological behavior of polymeric sulfated surfactants is revealed using cryogenic high-resolution electron microscopy (cryo-HRSEM). The polysodium N-undecenoyl-L-leucine sulfate (poly-L-SUCLS) shows distinct tubular structure, while polysodium N-undecenoyl-L-valine sulfate (poly-L-SUCVS) also shows tubular morphology but without any distinct order of the tubes. On the other hand, polysodium N-undecenoyl-L-isoleucine sulfate (poly-L-SUCILS) displays random distribution of coiled/curved filaments with heavy association of tightly and loosely bound water. All three polymeric sulfated surfactants are compared for enantio-separation of broad range of structurally diverse racemic compounds at very acidic, neutral and basic pH conditions in micellar electrokinetic chromatography (MEKC). A small combinatorial library of 10 structurally related phenylethylamines (PEAs) is investigated for chiral separation under acidic and moderately acidic to neutral pH conditions using an experimental design. In contrast to neutral pH conditions, at acidic pH, significantly enhanced chiral resolution is obtained for class I and class II PEAs due to the compact structure of polymeric sulfated surfactants. It is observed that the presence of hydroxy group on the benzene ring of PEAs resulted in deterioration of enantioseparation. A sensitive MEKC-mass spectrometry (MS) method is developed for one of the PEA (e.g., (±)-pseudoephedrine) in human urine. Very low limit of detection (LOD) is obtained at pH 2.0 (LOD 325 ng/mL), which is ca 16 times better compared to pH 8.0 (LOD 5.2 µg/mL). Other broad range of chiral analytes (

  17. 21 CFR 184.1307 - Ferric sulfate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Substances Affirmed as GRAS § 184.1307 Ferric sulfate. (a) Ferric sulfate (iron (III) sulfate, Fe2(SO4)3 CAS... treating ferric oxide or ferric hydroxide with sulfuric acid. (b) The ingredient must be of a...

  18. 21 CFR 184.1307 - Ferric sulfate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... Substances Affirmed as GRAS § 184.1307 Ferric sulfate. (a) Ferric sulfate (iron (III) sulfate, Fe2(SO4)3 CAS... treating ferric oxide or ferric hydroxide with sulfuric acid. (b) The ingredient must be of a...

  19. Chemical residuals in the environment and on chicken carcasses associated with scalding chickens in an acidic, copper sulfate-based commercial sanitizer during poultry processing.

    PubMed

    Russell, Scott M

    2008-01-01

    A study was conducted to determine if an acidic, copper sulfate-based commercial sanitizer evolves into surrounding air when introduced in a commercial poultry scalder. Two identical slaughter lines in a large poultry processing plant were used. One scalder was dosed with the sanitizer, and the other one was not. Four air samples were collected per day over the treated and control lines by an impingement method for 4 days for each of the two lines. Results showed that dosing the scalder with an acidic, copper sulfate-based commercial sanitizer resulted in no significant increase (P < or = 0.05) in the levels of the chemical components (sulfuric acid, ammonium sulfate, and copper sulfate) in the air above the scalder. Another study was conducted to evaluate the effect of the addition of this sanitizer during scalding on chemical residuals on chicken skin, meat, and fat. Five chickens were tagged and scalded in commercial scald water (136 degrees F [57.8 degrees C]), and five chickens were tagged and scalded in scald water (136 degrees F) treated with an acidic, copper sulfate-based commercial sanitizer as above. The chickens for both the control and treated lines were allowed to continue down the processing line and be exposed to the various washes (inside and outside bird washer and on-line reprocessing system) and the chiller. Skin, breast meat, and fat were removed from each carcass and analyzed. Three repetitions were conducted. Results demonstrated that there was no significant difference (P < or = 0.05) in the amount of sulfuric acid, ammonium sulfate, or copper sulfate recovered from these carcass parts.

  20. Formation of a Phyllosilicate-, K-feldspar-, and Sulfate-Bearing Hematite Ridge on Mauna Kea Volcano, Hawaii, Under Hydrothermal, Acid-Sulfate Conditions: Process and Mineralogical Analog for the Hematite Ridge on Mt. Sharp, Gale Crater, Mars.

    NASA Astrophysics Data System (ADS)

    Ming, D. W.; Morris, R. V.; Adams, M. E.; Catalano, J. G.; Graff, T. G.; Arvidson, R. E.; Guinness, E. A.; Hamilton, J. C.; Mertzman, S. A.; Fraeman, A.

    2015-12-01

    The Mars Science Laboratory rover Curiosity is currently moving upslope on Mt. Sharp in Gale Crater toward a hematite-bearing ridge. This hematite exposure was originally detected in CRISM spectra and subsequently mapped as part of a ~200 m wide, 6.5 km long ridge extending roughly parallel to the base of Mt. Sharp. CRISM spectra in the region suggest that hematite, smectite, and hydrated sulfates occur as secondary phases in lower layers of Mt. Sharp, separated by an unconformity from overlying anhydrous strata. A potential process and mineralogical analog is a hematite-bearing and weathering-resistant stratum (ridge) is exposed on the Puu Poliahu cinder cone on Mauna Kea (MK) volcano, Hawaii. The MK ridge is the product of hydrothermal alteration of basaltic precursors under acid-sulfate conditions. We are acquiring chemical and mineralogical (VNIR, Mid-IR, and backscatter Moessbauer spectroscopy, and transmission XRD) data on the MK ridge area that correspond to rover and orbiting spacecraft measurements at Gale Crater and elsewhere. The hematite-bearing stratum does not have detectable sulfate minerals by XRD, and hematite is variably present as up to mm-sized black crystals which, together with associated trioctahedral smectite and K-feldspar (from XRD), imply hydrothermal conditions. Adjacent to the MK hematite-bearing stratum are sulfates (jarosite and alunite) that are evidence for aqueous alteration under acid-sulfate conditions, and more soluble sulfates are absent but such phases would not persist if formed because of annual precipitation. Dioctahedral smectite is associated with red hematite and alunite-rich samples. The black and red hematite zones have the highest and lowest MgO/Al2O3 and K2O/Na2O ratios, respectively. Hematite, smectite, jarosite, and K-feldspar have been detected by Curiosity XRD downslope from the Mt. Sharp hematite ridge. MK field work and samples were obtained with PISCES partnership and OMKM, MKMB, BLNR, and KKMC permissions.

  1. The solute carrier family 10 (SLC10): beyond bile acid transport

    PubMed Central

    da Silva, Tatiana Claro; Polli, James E.; Swaan, Peter W.

    2012-01-01

    The solute carrier (SLC) family 10 (SLC10) comprises influx transporters of bile acids, steroidal hormones, various drugs, and several other substrates. Because the seminal transporters of this family, namely, sodium/taurocholate cotransporting polypeptide (NTCP; SLC10A1) and the apical sodium-dependent bile acid transporter (ASBT; SLC10A2), were primarily bile acid transporters, the term “sodium bile salt cotransporting family” was used for the SLC10 family. However, this notion became obsolete with the finding of other SLC10 members that do not transport bile acids. For example, the sodium-dependent organic anion transporter (SOAT; SLC10A6) transports primarily sulfated steroids. Moreover, NTCP was shown to also transport steroids and xenobiotics, including HMG-CoA inhibitors (statins). The SLC10 family contains four additional members, namely, P3 (SLC10A3; SLC10A3), P4 (SLC10A4; SLC10A4), P5 (SLC10A5; SLC10A5) and SLC10A7 (SLC10A7), several of which were unknown or considered hypothetical until approximately a decade ago. While their substrate specificity remains undetermined, great progress has been made towards their characterization in recent years. SLC10A4 may participate in vesicular storage or exocytosis of neurotransmitters or mastocyte mediators, whereas SLC10A5 and SLC10A7 may be involved in solute transport and SLC10A3 may have a role as a housekeeping protein. Finally, the newly found role of bile acids in glucose and energy homeostasis, via the TGR5 receptor, sheds new light on the clinical relevance of ASBT and NTCP. The present mini-review provides a brief summary of recent progress on members of the SLC10 family. PMID:23506869

  2. Fabrication of calcium phosphate-calcium sulfate injectable bone substitute using hydroxy-propyl-methyl-cellulose and citric acid.

    PubMed

    Thai, Van Viet; Lee, Byong-Taek

    2010-06-01

    In this study, an injectable bone substitute (IBS) consisting of citric acid, chitosan, and hydroxyl propyl methyl cellulose (HPMC) as the liquid phase and tetra calcium phosphate (TTCP), dicalcium phosphate dihydrate (DCPD) and calcium sulfate dehydrate (CSD, CaSO4 x 2H2O) powders as the solid phase, were fabricated. Two groups were classified based on the percent of citric acid in the liquid phase (20, 40 wt%). In each groups, the HPMC percentage was 0, 2, and 4 wt%. An increase in compressive strength due to changes in morphology was confirmed by scanning electron microscopy images. A good conversion rate of HAp at 20% citric acid was observed in the XRD profiles. In addition, HPMC was not obviously affected by apatite formation. However, both HPMC and citric acid increased the compressive strength of IBS. The maximum compressive strength for IBS was with 40% citric acid and 4% HPMC after 14 days of incubation in 100% humidity at 37 degrees C.

  3. A multi-faceted approach to characterize acid-sulfate alteration processes in volcanic hydrothermal systems on Earth and Mars

    NASA Astrophysics Data System (ADS)

    Marcucci, Emma Cordts

    Acid-sulfate alteration is a dominant weathering process in high temperature, low pH, sulfur-rich volcanic environments. Additionally, hydrothermal environments have been proposed as locations where life could have originated on Earth. Based on the extensive evidence of flowing surface water and persistent volcanism, similar locations and processes could have existed on early Mars. Globally observed alteration mineral assemblages likely represent relic Martian hydrothermal settings. Yet the limited understanding of environmental controls, limits the confidence of interpreting the paleoconditions of these hydrothermal systems and assessing their habitability to support microbial life. This thesis presents a series of laboratory experiments, geochemical models, analog fieldwork, and Martian remote sensing to characterize distinguishing features and controls of acid-sulfate alteration. The experiments and models were designed to replicate alteration is a highly acidic, sulfurous, and hot field sites. The basaltic minerals were individually reacted in both experimental and model simulations with varying initial parameters to infer the geochemical pathways of acid-sulfate alteration on Earth and Mars. It was found that for a specific starting material, secondary mineralogies were consistent. Variations in pH, temperature and duration affected the abundance, shape, and size of mineral products. Additionally evaporation played a key role in secondary deposits; therefore, both alteration and evaporitic processes need to be taken into consideration. Analog volcanic sites in Nicaragua were used to supplement this work and highlight differences between natural and simulated alteration. In situ visible near-infrared spectroscopy demonstrated that primary lithology and gas chemistry were dominant controls of alteration, with secondary effects from environmental controls, such as temperature and pH. The spectroscopic research from the field was directly related to Mars

  4. Evidence for Siliceous Deposits Formed by Acid-Sulfate Alteration at Home Plate in Gusev Crater, Mars

    NASA Astrophysics Data System (ADS)

    Morris, R. V.; Ming, D. W.; Gellert, R.; Yen, A. S.; Clark, B. C.; Ruff, S. W.; Graff, T. G.; Arvidson, R. E.; Squyres, S. W.; Science Teams, T.

    2007-12-01

    The Alpha Particle X-ray Spectrometer (APXS) instrument on the Mars Exploration Rover (MER) Spirit measured three targets on or adjacent to Home Plate in Gusev Crater that have unusually high SiO2 concentrations (68 to 91%), unusually low FeO concentrations (1 to 7%, with total Fe as FeO), and unusually high TiO2/FeO ratios (0.2 to 1.2 by weight). Two targets are high albedo soil (Gertrude Weise) exposed by the rover wheels (Kenosha Comets and Lefty Ganote), and one target is a rock (Fuzzy Smith). Kenosha Comets has the highest SiO2 concentration, lowest FeO concentration, and highest TiO2/FeO ratio. Mineralogical evidence from the MER Miniature Thermal Emission Spectrometer (Mini-TES) suggests that high proportions of amorphous (non- crystalline) SiO2 account for the high SiO2 concentration of Gertrude Weise. Mini-TES data were not acquired for Fuzzy Smith. The spectral evidence for amorphous SiO2 includes deep emissivity minima near 9 and 21 microns. Amorphous SiO2 is typically characterized by a shoulder near 8 microns, but the Gertrude Weise spectra are instead characterized by a well-defined emissivity minimum. The difference is attributed to scattering and/or geometric effects. The chemistry of Gertrude Weise and Fuzzy Smith is very similar to that for a tholeiitic basaltic rock altered under acid-sulfate conditions in a fumarolic (hydrothermal) environment on Kilauea Volcano (Hawaii). The terrestrial acid sulfate alteration resulted in compositions having about 62 to 91% SiO2, 1 to 8% FeO, and 0.3 to 5 TiO2/FeO. The SiO2 and TiO2 are passively enriched while all other major elements are removed by leaching. XRD analysis shows that SiO2 and TiO2 are present as amorphous SiO2 (opal-A) and anatase, respectively. Alunite is also present. Thermal emission spectra of the Kilauea rock obtained from its exterior surface and from 500-1000 micron and <150 micron powders derived by grinding and sieving are all characterized by the emissivity features at 8, 9, and 21

  5. Chondroitin sulfate

    MedlinePlus

    ... in combination with glucosamine sulfate, shark cartilage, and camphor. Some people also inject chondroitin sulfate into the ... in combination with glucosamine sulfate, shark cartilage, and camphor seems to reduce arthritis symptoms. However, any symptom ...

  6. Enhanced adsorption of Methylene Blue from aqueous solution by chitosan-g-poly (acrylic acid)/vermiculite hydrogel composites.

    PubMed

    Liu, Yi; Zheng, Yian; Wang, Aiqin

    2010-01-01

    A series of chitosan-g-poly (acrylic acid)/vermiculite hydrogel composites were synthesized and used as adsorbents for the investigation of the effect of process parameters such as vermiculite content, pH of dye solution, contact time, initial concentration of dye solution, temperature, ionic strength and concentration of surfactant sodium dodecyl sulfate on the removal of Methylene Blue (MB) from aqueous solution. The results showed that the adsorption capacity for dye increased with increasing pH, contact time and initial dye concentration, but decreased with increasing temperature, ionic strength and sodium dodecyl sulfate concentration in the present of the surfactant. The adsorption kinetics of MB onto the hydrogel composite followed pseudo second-order kinetics and the adsorption equilibrium data obeyed Langmuir isotherm. By introducing 10 wt.% vermiculite into chitosan-g-poly (acrylic acid) polymeric network, the obtaining hydrogel composite showed the highest adsorption capacity for MB, and then could be regarded as a potential adsorbent for cationic dye removal in a wastewater treatment process.

  7. The Effect of Sodium Hyaluronate plus Sodium Chondroitin Sulfate Solution on Peritendinous Adhesion and Tendon Healing: An Experimental Study

    PubMed Central

    Tosun, Hacı Bayram; Gümüştaş, Seyit Ali; Kom, Mustafa; Uludağ, Abuzer; Serbest, Sancar; Eröksüz, Yesari

    2016-01-01

    Background: Adhesion formation following tendon injury is a serious clinical problem. Aims: In this experimental study, the effects of the combination of sodium hyaluronate (HA) and chondroitin sulfate (CS) on peritendinous adhesion and tendon healing were evaluated. Study Design: Animal experimentation. Methods: Twenty-one mature Sprague Dawley male rats were randomly divided into three equal groups. The rats’ Achilles tendons were cut and repaired with a modified Kessler technique. About 0.25 and 0.50 mL of the HA and CS (HA+CS) combination were injected subcutaneously into the repair site of the rats in groups 1 and 2, respectively, on days 0, 3, 7, and 10. The subjects in group 3 were used as the control group. At 6 weeks, all rats were euthanized. The tenotomy site was examined macroscopically in all animal subjects. Four samples were assigned to the histopathological examination group, and the others were assigned to the biomechanical assessment group. Results: Inflammation and adhesion in both treatment groups were observed at a lower rate than in the control group. The collagen filaments in both treatment groups were regular and the number was low when compared to the control group. However, there was no statistically significant difference between group 1 and the control group. The quantity, quality, and grade of the adhesions were statistically significantly lower in group 2 when compared with the other groups. The mean maximum stress strength in group 2 was statistically significantly higher than that in group 1 and the control group. Conclusion: Local administration of the HA+CS combination solution is a valid tool for preventing peritendinous adhesion after extrasynovial tendon repair such as Achilles tendon, and is a treatment option in such cases. PMID:27308069

  8. Seven-coordinate anion complex with a tren-based urea: binding discrepancy of hydrogen sulfate in solid and solution states.

    PubMed

    Pramanik, Avijit; Thompson, Bethtrice; Hayes, Trina; Tucker, Kimberly; Powell, Douglas R; Bonnesen, Peter V; Ellis, Erick D; Lee, Ken S; Yu, Hongtao; Hossain, Md Alamgir

    2011-06-21

    Structural characterization of a hydrogen sulfate complex with a tren-based urea suggests that the anion is coordinated with six NH···O bonds (d(N···O) = 2.857 (3) to 3.092 (3) Å) and one OH···O bond (d(O···O) = 2.57 (2) Å) from three receptors; however, in solution the anion is bound within the pseudo-cavity of one receptor.

  9. Near-real time infrared observations of acidic sulfates in /open quotes/clean/close quotes/ air at Mauna Loa, Hawaii

    SciTech Connect

    Johnson, S.A.; Kumar, R.

    1988-01-01

    Sulfuric acid and its partially or completely neutralized salts with ammonia are believed to result from the oxidation of sulfur dioxide in cloud water and in other heterogeneous media present in the atmosphere. Due to the natural abundance of ammonia and the ubiquitous presence of sulfur in the atmosphere, (NH/sub 4/)/sub 2/SO/sub 4/ is commonly the dominant chemical species in the ambient aerosol. The amounts of ammonium sulfates are expected to be very low in areas far removed from anthropogenic emissions of sulfur dioxide. The chemical composition of submicrometer aerosol particles was determined at the Mauna Loa Observatory (MLO) on Mauna Loa in Hawaii during an eight-day period in August 1986. The MLO site was selected for this measurement because it is the only ground-based aerosol observatory in the remote Pacific Ocean that allows extended sampling of aerosols in the free troposphere. Measurements were made using an attenuated total internal reflection (ATR) impactor system. The impactor collects size-fractionated submicrometer particles for analysis by ATR infrared spectroscopy. The collected samples were analyzed using an on-site Perkin Elmer dispersive infrared spectrophotometer. Infrared absorption spectra (4000 to 250 cm/sup /minus/1/) of the samples were obtained within minutes after the ATR substrates were removed from the impactor. Absorbances were measured for sulfate, nitrate, and ammonium. Acidic sulfate showed infrared absorbances at 600 cm/sup /minus/1/ and 1210 cm/sup /minus/1/ in addition. Results showed that ammonium sulfate was the dominant chemical species in the submicrometer particles. Over half of the nearly 40 samples collected showed an acidic sulfate component. Consecutive samples were found to change from completely neutralized ammonium sulfate to acidic ammonium sulfates in a two-hour time interval. 5 refs., 1 tab.

  10. The use of nanometer tetrabasic lead sulfate as positive active material additive for valve regulated lead-acid battery

    NASA Astrophysics Data System (ADS)

    Lang, Xiaoshi; Wang, Dianlong; Hu, Chiyu; Tang, Shenzhi; Zhu, Junsheng; Guo, Chenfeng

    2014-12-01

    Conventional tetrabasic lead sulfate used as positive active material additive shows the results of the low effective lead dioxide conversion rate due to the large grain size and crossed the crystal structure. In this paper, we study on a type of nanometer tetrabasic lead sulfate. Through the XRD and SEM test and Material Studio software calculation, the purity of tetrabasic lead sulfate is very high, the grain size of the nanometer 4BS is almost unanimous, and can be controlled below 200 nm. When charged and discharged in 1.75 V-2.42 V with the current density of 40 mA g-1, 80 mA g-1 and 160 mA g-1, the effective lead dioxide conversion rate of nanometer 4BS after formation can achieve to 83.48%, 71.42%, and 66.96%. Subsequently, the nanometer 4BS as additive is added to positive paste of lead-acid battery. When the batteries are tested galvanostatically between 1.75 V and 2.42 V at 0.25 C charge and 0.5 C discharge rates at room temperature. The ratio of adding nanometer 4BS is 0%, 1% and 4% and the initial discharge specific capacities are 60 mAh g-1, 65 mAh g-1 and 68 mAh g-1. After 80 cycles, the initial discharge capacity of positive active material with 1% nanometer 4BS decreased less than 10%, while adding 4% nanometer 4BS, the initial discharge capacity doesn't decrease obviously.

  11. 40 CFR 721.9595 - Alkyl benzene sulfonic acids and alkyl sulfates, amine salts (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkyl benzene sulfonic acids and alkyl... Significant New Uses for Specific Chemical Substances § 721.9595 Alkyl benzene sulfonic acids and alkyl...) The chemical substances identified generically as alkyl benzene sulfonic acids and alkyl...

  12. 40 CFR 721.9595 - Alkyl benzene sulfonic acids and alkyl sulfates, amine salts (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Alkyl benzene sulfonic acids and alkyl... Significant New Uses for Specific Chemical Substances § 721.9595 Alkyl benzene sulfonic acids and alkyl...) The chemical substances identified generically as alkyl benzene sulfonic acids and alkyl...

  13. 40 CFR 721.9595 - Alkyl benzene sulfonic acids and alkyl sulfates, amine salts (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Alkyl benzene sulfonic acids and alkyl... Significant New Uses for Specific Chemical Substances § 721.9595 Alkyl benzene sulfonic acids and alkyl...) The chemical substances identified generically as alkyl benzene sulfonic acids and alkyl...

  14. 40 CFR 721.9595 - Alkyl benzene sulfonic acids and alkyl sulfates, amine salts (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Alkyl benzene sulfonic acids and alkyl... Significant New Uses for Specific Chemical Substances § 721.9595 Alkyl benzene sulfonic acids and alkyl...) The chemical substances identified generically as alkyl benzene sulfonic acids and alkyl...

  15. 40 CFR 721.9595 - Alkyl benzene sulfonic acids and alkyl sulfates, amine salts (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Alkyl benzene sulfonic acids and alkyl... Significant New Uses for Specific Chemical Substances § 721.9595 Alkyl benzene sulfonic acids and alkyl...) The chemical substances identified generically as alkyl benzene sulfonic acids and alkyl...

  16. Evaporation kinetics of acetic acid-water solutions

    NASA Astrophysics Data System (ADS)

    Duffey, K.; Wong, N.; Saykally, R.; Cohen, R. C.

    2012-12-01

    The transport of water molecules across vapor-liquid interfaces in the atmosphere is a crucial step in the formation and evolution of cloud droplets. Despite decades of study, the effects of solutes on the mechanism and rate of evaporation and condensation remain poorly characterized. The present work aims to determine the effect of atmospherically-relevant solutes on the evaporation rate of water. In our experiments, we create a train of micron-sized droplets and measure their temperature via Raman thermometry as they undergo evaporation without condensation. Analysis of the cooling rate yields the evaporation coefficient (γ). Previous work has shown that inorganic salts have little effect on γ, with surface-adsorbing anions causing a slight reduction in the coefficient from that measured for pure water. Organic acids are ubiquitous in aqueous aerosol and have been shown to disrupt the surface structure of water. Here we describe measurements of the evaporation rate of acetic acid solutions, showing that acetic acid reduces γ to a larger extent than inorganic ions, and that γ decreases with increasing acetic acid concentration.

  17. Solution Preserves Nucleic Acids in Body-Fluid Specimens

    NASA Technical Reports Server (NTRS)

    Pierson, Duane L.; Stowe, Raymond P.

    2004-01-01

    A solution has been formulated to preserve deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) in specimens of blood, saliva, and other bodily fluids. Specimens of this type are collected for diagnostic molecular pathology, which is becoming the method of choice for diagnosis of many diseases. The solution makes it possible to store such specimens at room temperature, without risk of decomposition, for subsequent analysis in a laboratory that could be remote from the sampling location. Thus, the solution could be a means to bring the benefits of diagnostic molecular pathology to geographic regions where refrigeration equipment and diagnostic laboratories are not available. The table lists the ingredients of the solution. The functions of the ingredients are the following: EDTA chelates divalent cations that are necessary cofactors for nuclease activity. In so doing, it functionally removes these cations and thereby retards the action of nucleases. EDTA also stabilizes the DNA helix. Tris serves as a buffering agent, which is needed because minor contaminants in an unbuffered solution can exert pronounced effects on pH and thereby cause spontaneous degradation of DNA. SDS is an ionic detergent that inhibits ribonuclease activity. SDS has been used in some lysis buffers and as a storage buffer for RNA after purification. The use of the solution is straightforward. For example, a sample of saliva is collected by placing a cotton roll around in the subject's mouth until it becomes saturated, then the cotton is placed in a collection tube. Next, 1.5 mL of the solution are injected directly into the cotton and the tube is capped for storage at room temperature. The effectiveness of the solution has been demonstrated in tests on specimens of saliva containing herpes simplex virus. In the tests, the viral DNA, as amplified by polymerase chain reaction, was detected even after storage for 120 days.

  18. A mechanistic study of copper electropolishing in phosphoric acid solutions

    NASA Astrophysics Data System (ADS)

    Mansson, Andrew

    The microelectronics industry is using copper as the interconnect material for microchips. A study of copper electropolishing is important for the process development of a new, low downforce approach, which is being developed to replace chemical mechanical polishing (CMP) of the copper overburden. A promising technology is a combination of electropolishing with conventional CMP. Electropolishing of copper in phosphoric acid has been studied for, more than 70 years. Previous work has shown that the polishing rate, as measured by current density is directly related to the viscosity of the electrolyte. Also, the limiting species is water. In this study, a multidimensional design of experiments was performed to develop an in-depth model of copper electropolishing. Phosphoric acid was mixed with alcohols of different molecular weight and related viscosity to investigate how the solvents' properties affected polishing. The alcohols used were methanol, ethanol, isopropanol, butanol, ethylene glycol, and glycerol. The limiting current densities and electrochemical behavior of each solution was measured by potentiodynamic and potentiostatic experiments. Also, the kinematic viscosity and density were measured to determine the dynamic viscosity to investigate the relationship of current density and viscosity. Water, methanol, ethanol, and isopropanol solutions were also examined at 20°C to 60°C. Next, the relative percentage of dissociated phosphoric acid was measured by Raman spectroscopy for each polishing solution. Raman spectroscopy was also used to measure the relative dissociation of phosphoric acid inside the polishing film. Additionally, wafers were electropolished and electrochemical mechanically polished to investigate the effects of the different solvents, fluid flow, current, and potential. The results of these experiments have shown that the molecular mass and the ability of the solvent to dissociate phosphoric acid are the primary electrolyte properties that

  19. A decade of monitoring at Swiss Long-Term Forest Ecosystem Research (LWF) sites: can we observe trends in atmospheric acid deposition and in soil solution acidity?

    PubMed

    Pannatier, Elisabeth Graf; Thimonier, Anne; Schmitt, Maria; Walthert, Lorenz; Waldner, Peter

    2011-03-01

    Trends in atmospheric acid deposition and in soil solution acidity from 1995 or later until 2007 were investigated at several forest sites throughout Switzerland to assess the effects of air pollution abatements on deposition and the response of the soil solution chemistry. Deposition of the major elements was estimated from throughfall and bulk deposition measurements at nine sites of the Swiss Long-Term Forest Ecosystem Research network (LWF) since 1995 or later. Soil solution was measured at seven plots at four soil depths since 1998 or later. Trends in the molar ratio of base cations to aluminum (BC/Al) in soil solutions and in concentrations and fluxes of inorganic N (NO(3)-N + NH(4)-N), sulfate (SO(4)-S), and base cations (BC) were used to detect changes in soil solution chemistry. Acid deposition significantly decreased at three out of the nine study sites due to a decrease in total N deposition. Total SO(4)-S deposition decreased at the nine sites, but due to the relatively low amount of SO(4)-S load compared to N deposition, it did not contribute to decrease acid deposition significantly. No trend in total BC deposition was detected. In the soil solution, no trend in concentrations and fluxes of BC, SO(4)-S, and inorganic N were found at most soil depths at five out of the seven sites. This suggests that the soil solution reacted very little to the changes in atmospheric deposition. A stronger reduction in base cations compared to aluminum was detected at two sites, which might indicate that acidification of the soil solution was proceeding faster at these sites.

  20. Solution influence on biomolecular equilibria - Nucleic acid base associations

    NASA Technical Reports Server (NTRS)

    Pohorille, A.; Pratt, L. R.; Burt, S. K.; Macelroy, R. D.

    1984-01-01

    Various attempts to construct an understanding of the influence of solution environment on biomolecular equilibria at the molecular level using computer simulation are discussed. First, the application of the formal statistical thermodynamic program for investigating biomolecular equilibria in solution is presented, addressing modeling and conceptual simplications such as perturbative methods, long-range interaction approximations, surface thermodynamics, and hydration shell. Then, Monte Carlo calculations on the associations of nucleic acid bases in both polar and nonpolar solvents such as water and carbon tetrachloride are carried out. The solvent contribution to the enthalpy of base association is positive (destabilizing) in both polar and nonpolar solvents while negative enthalpies for stacked complexes are obtained only when the solute-solute in vacuo energy is added to the total energy. The release upon association of solvent molecules from the first hydration layer around a solute to the bulk is accompanied by an increase in solute-solvent energy and decrease in solvent-solvent energy. The techniques presented are expectd to displace less molecular and more heuristic modeling of biomolecular equilibria in solution.

  1. Hexane isomerization and cracking activity and intrinsic acidity of H-zeolites and sulfated zirconia-titania.

    PubMed

    Lónyi, Ferenc; Kovács, Anita; Valyon, József

    2006-02-02

    Adsorption of N2 was studied on zeolite H-Y, ultrastabilized H-Y (H-USY), H-mordenite, H-ZSM-5, H-beta, and on sulfated zirconia-titania (SZT) mixed oxide by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) at 298 K and at N2 pressures up to 9 bar. The adsorption-induced DeltanuOH red-shift of the nuOH bands was used as a measure of the intrinsic acid strength of the Brnønsted acid sites. The intrinsic acid strength of the solids follows the order of H-ZSM-5 approximately H-mordenite approximately H-beta > H-USY > SZT approximately H-Y. The solids were characterized by their hexane conversion activities at 553 K and 6.1 kPa hexane partial pressure. The reaction was shown to proceed predominantly by a bimolecular mechanism, while the reaction was first order in hexane and zero order in alkenes. The site-specific apparent rate constant of the bimolecular hexane conversion was shown to parallel the intrinsic acid strength of the samples, suggesting that the ratio of the apparent and the intrinsic activity, that is, the KA' equilibrium constant of alkane adsorption on the hydrocarbon-covered sorption sites, is hardly dependent on the catalyst structure.

  2. Acid hydrolysis of cellulose in zinc chloride solution

    SciTech Connect

    Cao, N.J.; Xu, Q.; Chen, L.F.

    1995-12-31

    The efficient conversion of cellulosic materials to ethanol has been hindered by the low yield of sugars, the high energy consumption in pretreatment processes, and the difficulty of recycling the pre-treatment agents. Zinc chloride may provide an alternative for pre-treating biomass prior to the hydrolysis of cellulose. The formation of a zinc-cellulose complex during the pretreatment of cellulose improves the yield of glucose in both the enzymatic and acid hydrolysis of cellulose. Low-temperature acid hydrolysis of cellulose in zinc chloride solution is carried out in two stages, a liquefaction stage and a saccharification stage. Because of the formation of zinc-cellulose complex in the first stage, the required amount of acid in the second stage has been decreased significantly. In 67% zinc chloride solution, a 99.5% yield of soluble sugars has been obtained at 70{degrees}C and 0.5M acid concentration. The ratio of zinc chloride to cellulose has been reduced from 4.5 to 1.5, and the yield of soluble sugars is kept above 80%. The rate of hydrolysis is affected by the ratio of zinc chloride to cellulose, acid concentration, and temperature.

  3. Method for extracting lanthanides and actinides from acid solutions

    DOEpatents

    Horwitz, E. Philip; Kalina, Dale G.; Kaplan, Louis; Mason, George W.

    1985-01-01

    A process for the recovery of actinide and lanthanide values from aqueous acidic solutions with an organic extractant having the formula: ##STR1## where .phi. is phenyl, R.sup.1 is a straight or branched alkyl or alkoxyalkyl containing from 6 to 12 carbon atoms and R.sup.2 is an alkyl containing from 3 to 6 carbon atoms. The process is suitable for the separation of actinide and lanthanide values from fission product values found together in high level nuclear reprocessing waste solutions.

  4. Solubility of acetic acid and trifluoroacetic acid in low-temperature (207-245 k) sulfuric acid solutions: implications for the upper troposphere and lower stratosphere.

    PubMed

    Andersen, Mads P Sulbaek; Axson, Jessica L; Michelsen, Rebecca R H; Nielsen, Ole John; Iraci, Laura T

    2011-05-05

    The solubility of gas-phase acetic acid (CH(3)COOH, HAc) and trifluoroacetic acid (CF(3)COOH, TFA) in aqueous sulfuric acid solutions was measured in a Knudsen cell reactor over ranges of temperature (207-245 K) and acid composition (40-75 wt %, H(2)SO(4)). For both HAc and TFA, the effective Henry's law coefficient, H*, is inversely dependent on temperature. Measured values of H* for TFA range from 1.7 × 10(3) M atm(-1) in 75.0 wt % H(2)SO(4) at 242.5 K to 3.6 × 10(8) M atm(-1) in 40.7 wt % H(2)SO(4) at 207.8 K. Measured values of H* for HAc range from 2.2 × 10(5) M atm(-1) in 57.8 wt % H(2)SO(4) at 245.0 K to 3.8 × 10(8) M atm(-1) in 74.4 wt % H(2)SO(4) at 219.6 K. The solubility of HAc increases with increasing H(2)SO(4) concentration and is higher in strong sulfuric acid than in water. In contrast, the solubility of TFA decreases with increasing sulfuric acid concentration. The equilibrium concentration of HAc in UT/LS aerosol particles is estimated from our measurements and is found to be up to several orders of magnitude higher than those determined for common alcohols and small carbonyl compounds. On the basis of our measured solubility, we determine that HAc in the upper troposphere undergoes aerosol partitioning, though the role of H(2)SO(4) aerosol particles as a sink for HAc in the upper troposphere and lower stratosphere will only be discernible under high atmospheric sulfate perturbations.

  5. Acid sulfate alteration of fluorapatite, basaltic glass and olivine by hydrothermal vapors and fluids: Implications for fumarolic activity and secondary phosphate phases in sulfate-rich Paso Robles soil at Gusev Crater, Mars

    NASA Astrophysics Data System (ADS)

    Hausrath, E. M.; Golden, D. C.; Morris, R. V.; Agresti, D. G.; Ming, D. W.

    2013-01-01

    Phosphate-rich rocks and a nearby phosphate-rich soil, Paso Robles, were analyzed in Gusev Crater, Mars, by the Mars Exploration Rover Spirit and interpreted to be highly altered, possibly by hydrothermal or fumarolic alteration of primary, phosphate-rich material. To test mineral phases resulting from such alteration, we performed hydrothermal acid-vapor and acid-fluid experiments on olivine (Ol), fluorapatite (Ap), and basaltic glass (Gl) as single phases and a mixture of phases. Minerals formed include Ca-, Al-, Fe- and Mg-sulfates with different hydration states (anhydrite, bassanite, gypsum; alunogen; hexahydrite, and pentahydrite). Phosphate-bearing minerals formed included monocalcium phosphate monohydrate (MCP) (acid-vapor and acid-fluid alteration of fluorapatite only) and ferrian giniite (acid-fluid alteration of the Ol + Gl + Ap mixture). MCP is likely present in Paso Robles if primary Ca-phosphate minerals reacted with sulfuric acid with little transport of phosphate. Under fluid:rock ratios allowing transport of phosphate, a ferric phosphate phase such as ferrian giniite might form instead. Mössbauer measurements of ferrian giniite-bearing alteration products and synthetic ferrian giniite are consistent with Spirit's Mössbauer measurements of the ferric-bearing phase in Paso Robes soil, but are also consistent with ferric sulfate phases in the low-P soil Arad_Samra. Therefore, Mössbauer data alone do not constrain the fluid:rock ratio. However, the excess iron (hematite) in Paso Robles soil, which implies aqueous transport, combined with our laboratory experiments, suggest acid-sulfate alteration in a hydrothermal (fumarolic) environment at fluid:rock ratios sufficient to allow dissolution, transport, and precipitation of secondary chemical components including a ferric phosphate such as ferrian giniite.

  6. DC diaphragm discharge in water solutions of selected organic acids

    NASA Astrophysics Data System (ADS)

    Vyhnankova, Edita J.; Hammer, Malte U.; Reuter, Stephan; Krcma, Frantisek

    2015-07-01

    Effect of four simple organic acids water solution on a DC diaphragm discharge was studied. Efficiency of the discharge was quantified by the hydrogen peroxide production determined by UV-VIS spectrometry of a H2O2 complex formed with specific titanium reagent. Automatic titration was used to study the pH behaviour after the plasma treatment. Optical emission spectroscopy overview spectra were recorded and detailed spectra of OH band and Hβ line were used to calculate the rotational temperature and comparison of the line profile (reflecting electron concentration) in the acid solutions. Contribution to the topical issue "The 14th International Symposium on High Pressure Low Temperature Plasma Chemistry (HAKONE XIV)", edited by Nicolas Gherardi, Ronny Brandenburg and Lars Stollenwark

  7. Interaction of Ethyl Alcohol Vapor with Sulfuric Acid Solutions

    NASA Technical Reports Server (NTRS)

    Leu, Ming-Taun

    2006-01-01

    We investigated the uptake of ethyl alcohol (ethanol) vapor by sulfuric acid solutions over the range approx.40 to approx.80 wt % H2SO4 and temperatures of 193-273 K. Laboratory studies used a fast flow-tube reactor coupled to an electron-impact ionization mass spectrometer for detection of ethanol and reaction products. The uptake coefficients ((gamma)) were measured and found to vary from 0.019 to 0.072, depending upon the acid composition and temperature. At concentrations greater than approx.70 wt % and in dilute solutions colder than 220 K, the values approached approx.0.07. We also determined the effective solubility constant of ethanol in approx.40 wt % H2SO4 in the temperature range 203-223 K. The potential implications to the budget of ethanol in the global troposphere are briefly discussed.

  8. Recovery of rhenium from sulfuric acid solutions with activated coals

    SciTech Connect

    Troshkina, I.D.; Naing, K.Z.; Ushanova, O.N.; P'o, V.; Abdusalomov, A.A.

    2006-09-15

    Equilibrium and kinetic characteristics of rhenium sorption from sulfuric acid solutions (pH 2) by activated coals produced from coal raw materials (China) were studied. Constants of the Henry equation describing isotherms of rhenium sorption by activated coals were calculated. The effective diffusion coefficients of rhenium in the coals were determined. The dynamic characteristics of rhenium sorption and desorption were determined for the activated coal with the best capacity and kinetic characteristics.

  9. Enhancement of bacterial iron and sulfate respiration for in situ bioremediation of acid mine drainage sites: a case study

    SciTech Connect

    Bilgin, A.A.; Harrington, J.M.; Silverstein, J.

    2007-08-15

    The prevention of acid mine drainage (AMD) in situ is more attractive than down-gradient treatment alternatives that do not involve source control. AMD source control can be achieved by shifting the microbial activity in the sulfidic rock from pyrite oxidation to anaerobic heterotrophic activity. This is achieved by adding biodegradable organic carbon amendments to the sulfidic rock. This technique was applied to an abandoned coal mine pool in Pennsylvania. The pool had a pH of 3.0 to 3.5. Following treatment, near-neutral pH and decreased effluent heavy metal concentrations were achieved. In situ bioremediation by the enhancement of bacterial iron and sulfate reduction is a promising technology for AMD prevention.

  10. Sulfation pathways in plants.

    PubMed

    Koprivova, Anna; Kopriva, Stanislav

    2016-11-25

    Plants take up sulfur in the form of sulfate. Sulfate is activated to adenosine 5'-phosphosulfate (APS) and reduced to sulfite and then to sulfide when it is assimilated into amino acid cysteine. Alternatively, APS is phosphorylated to 3'-phosphoadenosine 5'-phosphosulfate (PAPS), and sulfate from PAPS is transferred onto diverse metabolites in its oxidized form. Traditionally, these pathways are referred to as primary and secondary sulfate metabolism, respectively. However, the synthesis of PAPS is essential for plants and even its reduced provision leads to dwarfism. Here the current knowledge of enzymes involved in sulfation pathways of plants will be summarized, the similarities and differences between different kingdoms will be highlighted, and major open questions in the research of plant sulfation will be formulated.

  11. Sulfate in fetal development.

    PubMed

    Dawson, Paul A

    2011-08-01

    Sulfate (SO(4)(2-)) is an important nutrient for human growth and development, and is obtained from the diet and the intra-cellular metabolism of sulfur-containing amino acids, including methionine and cysteine. During pregnancy, fetal tissues have a limited capacity to produce sulfate, and rely on sulfate obtained from the maternal circulation. Sulfate enters and exits placental and fetal cells via transporters on the plasma membrane, which maintain a sufficient intracellular supply of sulfate and its universal sulfonate donor 3'-phosphoadenosine 5'-phosphosulfate (PAPS) for sulfate conjugation (sulfonation) reactions to function effectively. Sulfotransferases mediate sulfonation of numerous endogenous compounds, including proteins and steroids, which biotransforms their biological activities. In addition, sulfonation of proteoglycans is important for maintaining normal structure and development of tissues, as shown for reduced sulfonation of cartilage proteoglycans that leads to developmental dwarfism disorders and four different osteochondrodysplasias (diastrophic dysplasia, atelosteogenesis type II, achondrogenesis type IB and multiple epiphyseal dysplasia). The removal of sulfate via sulfatases is an important step in proteoglycan degradation, and defects in several sulfatases are linked to perturbed fetal bone development, including mesomelia-synostoses syndrome and chondrodysplasia punctata 1. In recent years, interest in sulfate and its role in developmental biology has expanded following the characterisation of sulfate transporters, sulfotransferases and sulfatases and their involvement in fetal growth. This review will focus on the physiological roles of sulfate in fetal development, with links to human and animal pathophysiologies.

  12. INNOVATIVE, IN SITU TREATMENT OF ACID MINE DRAINAGE USING SULFATE REDUCING BACTERIA

    EPA Science Inventory

    Acid generation in abandoned mines is a widespread problem. There are a numberous quantity of abandoned mines in the west which have no power source, have limited physical accessibility and have limited remediation funds available. Acid is produced chemically, through pyritic min...

  13. Fast hybridization solution for the detection of immobilized nucleic acids.

    PubMed

    Yang, T T; Kain, S R

    1995-03-01

    We have developed a fast hybridization solution, termed ExpressHyb, for the rapid and sensitive detection of nucleic acids immobilized on membrane supports. This solution reduces typical hybridization times of 12-24 h to as little as 1 h while simultaneously increasing the sensitivity of detection in many applications. Using ExpressHyb, human beta-actin mRNA was detected on a human multiple tissue Northern (MTN) blot following a 30-min hybridization, with optimal detection occurring with a 1-h hybridization interval. The moderately abundant human glyceraldehyde-3-phosphate dehydrogenase (G3PDH) mRNA was detected using similar hybridization conditions and yielded improved signal-to-background characteristics relative to overnight hybridizations in conventional solutions. ExpressHyb can be used with either 32P- or digoxigenin-labeled probes and works effectively with both cDNA and oligonucleotide probes. For non-isotopic detection in particular, ExpressHyb reduces the nonspecific background commonly encountered with this technique. In cDNA library screening, ExpressHyb was found to both reduce the time required for effective hybridizations and to increase the number of positive colonies obtained relative to conventional overnight procedures. Taken together, these results illustrate the broad capability of ExpressHyb Hybridization Solution to improve nucleic acid detection in a variety of important techniques.

  14. Sonolysis of an oxalic acid solution under xenon lamp irradiation.

    PubMed

    Tanaka, Hisashi; Harada, Hisashi

    2010-06-01

    The photosonolysis of oxalic acid was carried out in an Ar atmosphere. The detectable products of sonolysis were CO(2), CO, H(2), and H(2)O(2). The yield of CO(2) was higher than that for the sum of sonolysis and photolysis reactions. Namely, a synergistic effect was observed during simultaneous irradiations of 200 kHz ultrasound and Xe lamp. The degradation of oxalic acid was promoted by active species such as H(2)O(2) produced from water by sonolysis. An oxalic acid-H(2)O(2) complex is likely to be present in the solution, but could not be detected. The effects of not only the photo-irradiation but also the thermal or incident energy during Xe lamp illumination were also considered.

  15. Combined sulfur K-edge XANES-EXAFS study of the effect of protonation on the sulfate tetrahedron in solids and solutions.

    PubMed

    Pin, S; Huthwelker, T; Brown, M A; Vogel, F

    2013-09-05

    Sulfur K-edge X-ray absorption spectroscopy (XAS) has been used to distinguish between aqueous and solid sulfates and to investigate changes in their speciation. Data have been collected for tetrahedrally coordinated S in K2SO4 and KHSO4 solids and aqueous solutions. With a first qualitative analysis of the X-ray absorption near-edge structure (XANES) spectra, it has been observed that those for solids are much more structured and distinguishable from those of aqueous solutions. The protonation state has a strong effect on the white line of sulfates and has been assigned to the different charge delocalization in the samples, the effect of the solvating water molecules and multiple scattering effects. In the extended X-ray absorption fine structure (EXAFS) spectra, the backscattering from the first O shell dominated the EXAFS fine structure function, χ(k), but the nonlinear multiple scattering contributions occurring in the first coordination shell are significant and must be considered in the EXAFS analysis. The intensity of these contributions strongly depend on the symmetry of the system. For a distorted tetrahedron, the intensity of the multiple scattering contributions is less than that found in a regular tetrahedron. The FEFF code has been used to model the contributions of the multiple-scattering processes. The observed experimental evidence in the XAS data can be used to distinguish between sulfates in solids and liquids. This is applicable to many chemical, geochemical, and biological systems.

  16. Solute-solvent interactions in micellar electrokinetic chromatography. Characterization of sodium dodecyl sulfate-Brij 35 micellar systems for quantitative structure-activity relationship modelling.

    PubMed

    Rosés, M; Ràfols, C; Bosch, E; Martínez, A M; Abraham, M H

    1999-06-11

    The solvation parameter model has been applied to the characterization of micellar electrokinetic chromatographic (MEKC) systems with mixtures of sodium dodecyl sulfate and Brij 35 as surfactant. The variation in MEKC surfactant composition results in changes in the coefficients of the correlation equation, which in turns leads to information on solute-solvent and solute-micelle interactions. Since the same solvation model can be used to describe many biological processes, particular MEKC surfactant compositions can be selected that model the solute-solvent interactions of some of these processes. Two different MEKC systems have been selected to model the solute-solvent interactions of two processes of biological interest (octanol-water partition and tadpole narcosis).

  17. Trace anion determination in concentrated hydrofluoric acid solutions by two-dimensional ion chromatography I. Matrix elimination by ion-exclusion chromatography.

    PubMed

    Vermeiren, Koen

    2005-08-26

    Since years, ion exclusion chromatography (ICE) has been the standard method to separate strong acid analyte anions from concentrated weak acid matrices such as hydrofluoric acid (HF). In this work, the commercially available IonPac ICE-AS 1 column was used to separate trace levels of chloride, nitrate, sulfate and phosphate from HF solutions at 20% (w/w). The efficiency of the separation was studied in more detail using techniques such as ion chromatography (IC), inductively coupled plasma optical emission spectrometry (ICP-OES) and ICP-mass spectrometry (ICP-MS). For 20% (w/w) HF solutions and at a water carrier flow-rate of 0.50 ml/min, the cut window was set from 8.5 to 14.5 min. Under these conditions, analyte recoveries of better than 90% were obtained for chloride, nitrate and sulfate, but only about 75% for phosphate. The HF rejection efficiency was better than 99.9%. It was found that the ICP techniques, measuring total element levels and not species, yielded significantly higher recoveries for phosphorus and sulfur compared to IC. Evidence will be given that part of the added phosphorus (approximately 15% for an addition of 10 mg PO4/kg) is present as mono-fluorophosphoric acid (H2FPO3). In the case of sulfate, the difference between IC and ICP-MS could be attributed to an important matrix effect from the residual HF concentration.

  18. Effectiveness of copper sulfate, potassium permanganate, and peracetic acid to reduce mortality and infestation of Ichthyobodo nector in channel catfish Ictalurus punctatus (Rafinesque 1818)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ichthyobodo necator is a single celled bi-flagellate parasite, and in high density can causes significant mortality in young fish. Copper sulfate (CuSO4), potassium permanganate (KMnO4) and peracetic acid (PAA) were evaluated for effectiveness against ichthyobodosis. Treatments were: untreated con...

  19. Acid-fog deposition at Kilauea volcano: A possible mechanism for the formation of siliceous-sulfate rock coatings on Mars

    NASA Astrophysics Data System (ADS)

    Schiffman, Peter; Zierenberg, Robert; Marks, Naomi; Bishop, Janice L.; Darby Dyar, M.

    2006-11-01

    On the summit of Kilauea volcano, sulfur dioxide, which is continuously emitted from Halemaumau crater and rapidly sequestered into sulfuric-acid rich aerosol entrained in the prevailing trade winds, is subsequently precipitated as acid fog immediately downwind from Kilauea caldera in the Kau Desert. The characteristic pH of surface tephra deposits is <4.0 in Sand Wash, a region of nearly continuous, acidic aerosol fallout immediately southwest of the caldera. Vertical exposures of unconsolidated tephras of the Keanakakoi Ash found within fissures and small, dry gullies are coated with thin rock coatings of amorphous silica and jarosite. These rock coatings are formed via an evaporative mechanism whereby acidic pore fluids, circulating in the upper few meters within the highly porous tephra, are wicked toward the walls of the gullies. Geochemical modeling of the rock coating formation process implies that the sulfate formation via evaporation occurs subsequent to minimal interaction of acidic pore fluids with the basaltic tephra. This also suggests that the cycle from acid-fog fallout to precipitation of the siliceous-sulfate rock coatings must occur quite rapidly. Acid-fog deposition of sulfate and silica at Kilauea may provide one mechanism for the origin of jarosite-bearing outcrops on Mars.

  20. Thermochemical comparisons of homogeneous and heterogeneous acids and bases. 1. Sulfonic acid solutions and resins as prototype Broensted acids

    SciTech Connect

    Arnett, E.M.; Haaksma, R.A.; Chawla, B.; Healy, M.H.

    1986-08-06

    Heats of ionization by thermometric titration for a series of bases (or acids) can be used to compare solid acids (or bases) with liquid analogues bearing the same functionalities in homogeneous solutions. The method is demonstrated for Broensted acids by reacting a series of substituted nitrogen bases with solutions of p-toluenesulfonic acid (PTSA) in acetonitrile and with suspensions of the microporous polymeric arylsulfonic acid resin-Dowex 50W-X8 in the same solvent. Under well-controlled anhydrous conditions there is a good correlation (r = 0.992) between the heats of reaction of the bases with the homogeneous and heterogeneous acid systems, but the homogeneous system gives a more exothermic interaction by 3-4 kcal mol/sup -1/ for a series of 29 substituted pyrimidines, anilines, and some other amines. This difference may be attributed to homohydrogen bonding interactions between excess acid and sulfonate anion sites which are more restricted geometrically in the resin than in solution. Other factors which affect the enthalpy change for the acid-base interaction are the acid/base ratio, the water content of the sulfonic acid, the solvent, and the resin structure (e.g., microporous vs. macroporous). Steric hindrance in the base does not differentiate solid from homogeneous acid. In addition to the use of titration calorimetry, heats of immersion are reported for the Dowex-arylsulfonic acid resins and the Nafion-perfluorinated sulfonic acid resin in a series of basic liquids. The results are compared with each other and with those from a previous study of several varieties of coal.

  1. Recovery of hydrochloric acid from the waste acid solution by diffusion dialysis.

    PubMed

    Xu, Jing; Lu, Shuguang; Fu, Dan

    2009-06-15

    Diffusion dialysis using a series of anion exchange membranes was employed to recover HCl acid from the waste acid solution. Effects of flow rate, flow rate ratio of water to feed, and Fe ion concentration on the recovery of HCl were investigated. It was found that the flow rate ratio was an important factor in the diffusion dialysis operation, and the recovered HCl concentration and Fe ion concentration in diffusate decreased significantly with the change of flow rate ratio from 0.4 to 1.7. In addition, the higher the Fe ion concentration in the feed, the higher the Fe leakage in the recovered acid solution. The HCl recovery efficiency was influenced not only by the recovered acid concentration, but also the outlet flow rate. While using the actual pot galvanizing waste HCl solution with the co-existence of 2.70 mol/L of Fe and 0.07 mol/L of Zn ions, over 88% HCl recovery efficiency could be achieved and Fe leakage was within the range of 11-23%. However, over 56% of Zn leakage was found due to the formation of negative Zn complexes in solution, which was unfavorable for the recovered acid reuse.

  2. Redox transformation, solid phase speciation and solution dynamics of copper during soil reduction and reoxidation as affected by sulfate availability

    NASA Astrophysics Data System (ADS)

    Fulda, Beate; Voegelin, Andreas; Ehlert, Katrin; Kretzschmar, Ruben

    2013-12-01

    In periodically flooded soils, interactions of Cu with biogenic sulfide formed during soil reduction lead to the precipitation of sparingly soluble Cu-sulfides. In contaminated soils, however, the amounts of Cu can exceed the amount of sulfate available for microbial reduction to sulfide. In laboratory batch experiments, we incubated a paddy soil spiked to ∼4.4 mmol kg-1 (280 mg kg-1) Cu(II) to monitor temporal changes in the concentrations of dissolved Cu and the speciation of solid-phase Cu during 40 days of soil reduction and 28 days of reoxidation as a function of initially available reducible sulfate (0.06, 2.09 or 5.92 mmol kg-1). Using Cu K-edge EXAFS spectroscopy, we found that a large fraction of Cu(II) became rapidly reduced to Cu(I) (23-39%) and Cu(0) (7-17%) before the onset of sulfate reduction. Combination with results from sequential Cu extraction and chromium reducible sulfur (CRS) data suggested that complexation of Cu(I) by reduced organic S groups (Sorg) may be an important process during this early stage. In sulfate-depleted soil, Cu(0) and Cu(I)-Sorg remained the dominant species over the entire reduction period, whereas in soils with sufficient sulfate, initially formed Cu(0) and (remaining) Cu(II) became transformed into Cu-sulfide during continuing sulfate reduction. The formation of Cu(0), Cu(I)-Sorg, and Cu-sulfide led to an effective decrease in dissolved Cu concentrations. Differences in Cu speciation at the end of soil reduction however affected the dynamics of Cu during reoxidation. Whereas Cu(0) was rapidly oxidized to Cu(II), more than half of the S-coordinated Cu fraction persisted over 14 days of aeration. Our results show that precipitation of Cu(0) and complexation of Cu(I) by reduced organic S groups are important processes in periodically flooded soils if sulfide formation is limited by the amount of available sulfate or the duration of soil flooding. The speciation changes of Cu described in this study may also affect the

  3. Toluene nitration in irradiated nitric acid and nitrite solution

    SciTech Connect

    Gracy Elias; Bruce J. Mincher; Stephen P. Mezyk; Jim Muller; Leigh R. Martin

    2011-04-01

    The kinetics, mechanisms, and stable products produced for the aryl alkyl mild ortho-para director - toluene, in irradiated nitric acid and neutral nitrite solutions were investigated using ?, and pulse radiolysis. Electron pulse radiolysis was used to determine the bimolecular rate constants for the reaction of toluene with different transient species produced by irradiation. HPLC with UV detection was primarily used to assess the stable reaction products. GC-MS and LC-MS were used to confirm the results from HPLC. Free-radical nitration reaction products were found in irradiated acidic and neutral media. In acidic medium, the ring substitution and side chain substitution and oxidation produced different nitro products. In ring substitution, nitrogen oxide radicals were added mainly to hydroxyl radical-produced cyclohexadienyl radical, and in side chain substitution they were added to the carbon-centered benzyl radical produced by H-atom abstraction. In neutral nitrite toluene solution, radiolytic ring nitration products approached a statistically random distribution, suggesting a free-radical reaction involving addition of the •NO2 radical.

  4. Efficacy of ε-polylysine, lauric arginate, or acidic calcium sulfate applied sequentially for Salmonella reduction on membrane filters and chicken carcasses.

    PubMed

    Benli, Hakan; Sanchez-Plata, Marcos X; Keeton, Jimmy T

    2011-05-01

    Salmonella contamination continues to be one of the major concerns for the microbiological safety of raw poultry products. Application of more than one decontamination agent as a multihurdle intervention to carcasses in a processing line might produce greater reductions than one treatment alone due to different modes of action of individual antimicrobials. In this study, all possible two-way combinations and individual applications of ε-polylysine (EPL), lauric arginate (LAE), and acidic calcium sulfate (ACS) solutions were evaluated for their effects against Salmonella enterica serovars, including Enteritidis and Typhimurium, using a sterile membrane filter model system. The combinations that provided higher Salmonella reductions were further evaluated on inoculated chicken carcasses in various concentrations applied in a sequential manner. Sequential spray applications of 300 mg of EPL per liter followed by 30% ACS and of 200 mg of LAE per liter followed by 30% ACS produced the highest Salmonella reductions on inoculated chicken carcasses, by 2.1 and 2.2 log CFU/ml, respectively. Our results indicated that these sequential spray applications of decontamination agents are effective for decreasing Salmonella contamination on poultry carcasses, but further studies are needed to determine the effectiveness of these combinations over a storage period.

  5. Inactivation of Salmonella spp. and Listeria spp. by Palmitic, Stearic, and Oleic Acid Sophorolipids and Thiamine Dilauryl Sulfate

    PubMed Central

    Zhang, Xuejie; Ashby, Richard; Solaiman, Daniel K. Y.; Uknalis, Joseph; Fan, Xuetong

    2016-01-01

    Food contaminated with human pathogens, such as Salmonella spp. and Listeria monocytogenes, frequently causes outbreaks of foodborne illness. Consumer concern over the use of synthesized antimicrobials to enhance microbial food safety has led to a search of natural alternatives. The objectives of this study were to evaluate the antimicrobial activity of various types of sophorolipids (SLs) and thiamine dilauryl sulfate (TDS) against pathogenic Salmonella spp. and Listeria spp. Both free and lactonic forms of SLs were synthesized from Candida bombicola using palmitic, stearic, and oleic acids as co-feedstocks. TDS and purified SLs were used to treat cocktails of Salmonella spp. and Listeria spp. Results showed that lactonic SLs had higher antimicrobial activity than the free-acid form, and Gram-positive Listeria spp. were more susceptible to SLs and TDS than Gram-negative Salmonella spp. Listeria populations were reduced from an initial concentration of 7.2 log CFU/mL to a non-detectible level within a 1 min treatment of 0.1% (w/v) lactonic SLs and TDS in the presence of 20% ethanol, which itself did not significantly reduce the populations. There were no significant differences in the antimicrobial efficacy among palmitic, stearic, and oleic acid-based SLs against Salmonella or Listeria spp. Ethanol was utilized to improve the antimicrobial activity of free-acid SLs against Gram-negative bacteria. In general, TDS was more effective than the SLs against Salmonella and Listeria spp. scanning electron microscopy and transmission electron microscopy images showed that SLs and TDS damaged Listeria cell membranes and resulted in cell lysis. Overall, our results demonstrated that SLs and TDS in the presence of ethanol can be used to inactivate foodborne pathogens, especially Gram-positive bacteria. PMID:28066390

  6. Inactivation of Salmonella spp. and Listeria spp. by Palmitic, Stearic, and Oleic Acid Sophorolipids and Thiamine Dilauryl Sulfate.

    PubMed

    Zhang, Xuejie; Ashby, Richard; Solaiman, Daniel K Y; Uknalis, Joseph; Fan, Xuetong

    2016-01-01

    Food contaminated with human pathogens, such as Salmonella spp. and Listeria monocytogenes, frequently causes outbreaks of foodborne illness. Consumer concern over the use of synthesized antimicrobials to enhance microbial food safety has led to a search of natural alternatives. The objectives of this study were to evaluate the antimicrobial activity of various types of sophorolipids (SLs) and thiamine dilauryl sulfate (TDS) against pathogenic Salmonella spp. and Listeria spp. Both free and lactonic forms of SLs were synthesized from Candida bombicola using palmitic, stearic, and oleic acids as co-feedstocks. TDS and purified SLs were used to treat cocktails of Salmonella spp. and Listeria spp. Results showed that lactonic SLs had higher antimicrobial activity than the free-acid form, and Gram-positive Listeria spp. were more susceptible to SLs and TDS than Gram-negative Salmonella spp. Listeria populations were reduced from an initial concentration of 7.2 log CFU/mL to a non-detectible level within a 1 min treatment of 0.1% (w/v) lactonic SLs and TDS in the presence of 20% ethanol, which itself did not significantly reduce the populations. There were no significant differences in the antimicrobial efficacy among palmitic, stearic, and oleic acid-based SLs against Salmonella or Listeria spp. Ethanol was utilized to improve the antimicrobial activity of free-acid SLs against Gram-negative bacteria. In general, TDS was more effective than the SLs against Salmonella and Listeria spp. scanning electron microscopy and transmission electron microscopy images showed that SLs and TDS damaged Listeria cell membranes and resulted in cell lysis. Overall, our results demonstrated that SLs and TDS in the presence of ethanol can be used to inactivate foodborne pathogens, especially Gram-positive bacteria.

  7. Donnan membrane speciation of Al, Fe, trace metals and REEs in coastal lowland acid sulfate soil-impacted drainage waters.

    PubMed

    Jones, Adele M; Xue, Youjia; Kinsela, Andrew S; Wilcken, Klaus M; Collins, Richard N

    2016-03-15

    Donnan dialysis has been applied to forty filtered drainage waters collected from five coastal lowland acid sulfate soil (CLASS) catchments across north-eastern NSW, Australia. Despite having average pH values<3.9, 78 and 58% of Al and total Fe, respectively, were present as neutral or negatively-charged species. Complementary isotope dilution experiments with (55)Fe and (26)Al demonstrated that only soluble (i.e. no colloidal) species were present. Trivalent rare earth elements (REEs) were also mainly present (>70%) as negatively-charged complexes. In contrast, the speciation of the divalent trace metals Co, Mn, Ni and Zn was dominated by positively-charged complexes and was strongly correlated with the alkaline earth metals Ca and Mg. Thermodynamic equilibrium speciation calculations indicated that natural organic matter (NOM) complexes dominated Fe(III) speciation in agreement with that obtained by Donnan dialysis. In the case of Fe(II), however, the free cation was predicted to dominate under thermodynamic equilibrium, whilst our results indicated that Fe(II) was mainly present as neutral or negatively-charged complexes (most likely with sulfate). For all other divalent metals thermodynamic equilibrium speciation calculations agreed well with the Donnan dialysis results. The proportion of Al and REEs predicted to be negatively-charged was also grossly underestimated, relative to the experimental results, highlighting possible inaccuracies in the stability constants developed for these trivalent Me(SO4)2(-) and/or Me-NOM complexes and difficulties in modeling complex environmental samples. These results will help improve metal mobility and toxicity models developed for CLASS-affected environments, and also demonstrate that Australian CLASS environments can discharge REEs at concentrations an order of magnitude greater than previously reported.

  8. Orbital Evidence for Clay and Acidic Sulfate Assemblages on Mars and Mineralogical Analogs from Rio Tinto, Spain

    NASA Astrophysics Data System (ADS)

    Kaplan, H. H.; Milliken, R.; Fernandez-Remolar, D. C.; Amils, R.; Robertson, K.; Knoll, A. H.

    2015-12-01

    A suite of enigmatic near-infrared reflectance spectra with a 'doublet' absorption between 2.2 and 2.3 µm is observed in CRISM (Compact Reconnaissance Imaging Spectrometer for Mars) hyperspectral images over Ius and Melas Chasma on Mars. The doublet-bearing deposits are found alongside other hydrated minerals including clays, sulfates, and silica, but the mineral(s) responsible for the spectral signature has yet to be identified. Reflectance spectra of rocks and sediments at Rio Tinto, Spain exhibit similar absorptions at airborne, field, and lab spatial scales. Coupled X-ray diffraction and reflectance spectra of these terrestrial examples indicate the absorption arises from a mixture of jarosite, a ferric sulfate, and Al-phyllosilicates (illite/muscovite). Detailed analysis of CRISM data over Ius and Melas Chasma suggests that these deposits also contain mixtures of jarosite and Al-phyllosilicate, where the latter may include halloysite, kaolinite and/or montmorillonite in addition to illite/muscovite. This interpretation is supported because (1) the two absorptions in the doublet feature vary independently, implying the presence of two or more phases, (2) the position of the absorptions is consistent with Al-OH and Fe-OH vibrations in both the Rio Tinto and CRISM spectra and (3) Al-phyllosilicates and jarosite are identified separately in nearby regions. Multiple formation mechanisms are proposed based on stratigraphy in Ius Chasma, where the strength of absorptions varies within a single stratigraphic unit as well as between different units. Mechanisms include authigenic formation of jarosite, which would indicate locally acidic and oxidizing conditions, mixed with detrial Al-phyllosilicates, or authigenic formation of Al-phyllosilicates and jarosite. Each implies different conditions in terms of aqueous geochemistry, redox, and sediment transport. Results from the field, lab, and CRISM analysis will be presented to discuss how placing these spectral

  9. Hyaluronic acid and glucosamine sulfate for adult Kashin-Beck disease: a cluster-randomized, placebo-controlled study.

    PubMed

    Xia, Chuan-Tao; Yu, Fang-Fang; Ren, Feng-Ling; Fang, Hua; Guo, Xiong

    2016-05-01

    To evaluate the efficacy and safety of hyaluronic acid (HA) and glucosamine sulfate (GS) in alleviating symptoms and improving function of Kashin-Beck disease (KBD). A cluster-randomized, placebo-controlled trial was conducted in 150 patients with KBD. Participants were randomly allocated to receive intra-articular injection hyaluronic acid (IAHA) for 4 weeks, oral GS for 12 weeks, or oral placebo for 12 weeks. The primary outcome measures were 20 % and 50 % reductions in pain from baseline measured by the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) index. Secondary outcome measures included WOMAC index parameters of pain, stiffness, and physical function. The third outcome measure was mean change in Lequence score. HA and GS were effective in reducing WOMAC pain by 20 % (differences of 43.5 % and 25.4 %) and 50 % (differences of 43.4 % and 26.9 %). Both HA and GS significantly reduced WOMAC pain, WOMAC stiffness, and WOMAC normalized score compared with placebo group (all P < 0.05). IAHA was significantly more effective than oral GS in improving WOMAC normalized score (P = 0.034), pain (P = 0.002), stiffness (P = 0.018), and function (P = 0.044). The results indicate that HA and GS were more effective than placebo in treating KBD and HA was more effective than GS.

  10. Cryo-transmission electron microscopy imaging of the morphology of submicrometer aerosol containing organic acids and ammonium sulfate.

    PubMed

    Veghte, Daniel P; Bittner, Danielle Rae; Freedman, Miriam Arak

    2014-03-04

    The effects of aerosol particles on heterogeneous atmospheric chemistry and climate are determined in part by the internal arrangement of compounds within the particles. To characterize the morphology of internally mixed aerosol particles in the accumulation mode size regime, we have used cryo-transmission electron microscopy to investigate the phase separation behavior of dry, submicrometer particles composed of ammonium sulfate mixed with carboxylic acids (adipic, azelaic, citric, glutaric, malonic, pimelic, suberic, and succinic acid). Determining the morphology of dry particles is important for understanding laboratory studies of aerosol optical properties, reactivity, and cloud condensation nucleus activity, results from field instruments where aerosol particles are dried prior to analysis, and atmospheric processes like deposition mode heterogeneous ice nucleation that occur on dried particles. We observe homogeneous morphologies for highly soluble organic compounds. For organic compounds with limited aqueous solubility, partially engulfed structures are observed. At intermediate aqueous solubilities, small particles are homogeneous and larger particles are partially engulfed. Results are compared to previous studies of liquid-liquid phase separation in supermicrometer particles and the impact of these dry particle morphologies on aerosol-climate interactions are discussed.

  11. GADOLINIUM OXALATE SOLUBILITY MEASUREMENTS IN NITRIC ACID SOLUTIONS

    SciTech Connect

    Pierce, R.

    2012-02-22

    HB-Line will begin processing Pu solutions during FY2012 that will involve the recovery of Pu using oxalate precipitation and filtration. After the precipitation and filtration processes, the filtrate solution will be transferred from HB-Line to H-Canyon. The presence of excess oxalate and unfiltered Pu oxalate solids in these solutions create a criticality safety issue if they are sent to H-Canyon without controls in H-Canyon. One approach involves H-Canyon receiving the filtrate solution into a tank that is poisoned with soluble gadolinium (Gd). Decomposition of the oxalate will occur within a subsequent H-Canyon vessel. The receipt of excess oxalate into the H-Canyon receipt tanks has the potential to precipitate a portion of the Gd poison in the receipt tanks. Because the amount of Gd in solution determines the maximum amount of Pu solids that H-Canyon can receive, H-Canyon Engineering requested that SRNL determine the solubility of Gd in aqueous solutions of 4-10 M nitric acid (HNO{sub 3}), 4-12 g/L Gd, and 0.15-0.25 M oxalic acid (H{sub 2}C{sub 2}O{sub 4}) at 25 C. The target soluble Gd concentration is 6 g/L. The data indicate that the target can be achieved above 6 M HNO{sub 3} and below 0.25 M H{sub 2}C{sub 2}O{sub 4}. For 6 M HNO{sub 3}, 10.5 g/L and 7 g/L Gd are soluble in 0.15 M and 0.25 M H{sub 2}C{sub 2}O{sub 4}, respectively. In 4 M HNO{sub 3}, the Gd solubility drops significantly to 2 g/L and 0.25 g/L in 0.15 M and 0.25 M H{sub 2}C{sub 2}O{sub 4}, respectively. The solubility of Gd at 8-10 M HNO{sub 3} exceeds the solubility at 6 M HNO{sub 3}. The data for 4 M HNO{sub 3} showed good agreement with data in the literature. To achieve a target of 6 g/L soluble Gd in solution in the presence of 0.15-0.25 M oxalate, the HNO{sub 3} concentration must be maintained at or above 6 M HNO{sub 3}.

  12. Plutonium and Americium Alpha Radiolysis of Nitric Acid Solutions.

    PubMed

    Horne, Gregory P; Gregson, Colin R; Sims, Howard E; Orr, Robin M; Taylor, Robin J; Pimblott, Simon M

    2017-02-02

    The yield of HNO2, as a function of absorbed dose and HNO3 concentration, from the α-radiolysis of aerated HNO3 solutions containing plutonium or americium has been investigated. There are significant differences in the yields measured from solutions of the two different radionuclides. For 0.1 mol dm(-3) HNO3 solutions, the radiolytic yield of HNO2 produced by americium α-decay is below the detection limit, whereas for plutonium α-decay the yield is considerably greater than that found previously for γ-radiolysis. The differences between the solutions of the two radionuclides are a consequence of redox reactions involving plutonium and the products of aqueous HNO3 radiolysis, in particular H2O2 and HNO2 and its precursors. This radiation chemical behavior is HNO3 concentration dependent with the differences between plutonium and americium α-radiolysis decreasing with increasing HNO3 concentration. This change may be interpreted as a combination of α-radiolysis direct effects and acidity influencing the plutonium oxidation state distribution, which in turn affects the radiation chemistry of the system.

  13. Sulfated chitosan/PVA absorbent membrane for removal of copper and nickel ions from aqueous solutions-Fabrication and sorption studies.

    PubMed

    Abu-Saied, M A; Wycisk, Ryszard; Abbassy, Moustafa M; El-Naim, G Abd; El-Demerdash, F; Youssef, M E; Bassuony, H; Pintauro, Peter N

    2017-06-01

    Novel absorbents for the removal of Cu(2+) and Ni(2+) ions from aqueous solutions were prepared from solution cast sulfated chitosan/polyvinyl alcohol membranes (SCS/PVA) and their properties were investigated. FTIR, SEM, XRD and TGA analyses were used to determine membrane structure. The effect of environmental parameters on absorption was studied, including pH, contact time, temperature and the initial concentration of Ni(2+) and Cu(2+) ions. Freundlich and Langmuir absorption isotherms were fitted to experimental data and a pseudo-second order rate equation was employed to model the kinetics of uptake for several copper and nickel ion concentrations. The results indicate that the affinity of an SCS/PVA membrane for Cu(2+) ions was higher than that for Ni(2+) ions. The study demonstrated that the SCS/PVA system can be utilized as highly efficient sorbents, to extract Ni(2+) and Cu(2+) from aqueous feed solutions.

  14. Adsorption of organic acids from dilute aqueous solution onto activated carbon

    SciTech Connect

    Wang, S.W.

    1980-06-01

    The radioisotope technique was used to study the removal of organic acid contaminants from dilute aqueous solutions onto activated carbon. Acetic acid, propionic acid, n-butyric acid, n-hexanoic acid and n-heptanoic acid were studied at 278, 298, and 313/sup 0/K. Three bi-solute acid mixtures (acetic and propionic acids, acetic and butanoic acids, and propionic and butanoic acids) were studied at 278 and 298/sup 0/K. Isotherms of the single-solute systems were obtained at three different temperatures in the very dilute concentration region (less than 1% by weight). These data are very important in the prediction of bi-solute equilibrium data. A Polanyi-based competitive adsorption potential theory was used to predict the bi-solute equilibrium uptakes. Average errors between calculated and experimental data ranges from 4% to 14%. It was found that the competitive adsorption potential theory gives slightly better results than the ideal adsorbed solution theory.

  15. Assessment of environmental controls on acid-sulfate alteration at active volcanoes in Nicaragua: Applications to relic hydrothermal systems on Mars

    NASA Astrophysics Data System (ADS)

    Hynek, Brian M.; McCollom, Thomas M.; Marcucci, Emma C.; Brugman, Kara; Rogers, Karyn L.

    2013-10-01

    A variety of secondary mineralogies has been detected on Mars from both orbiters and landers, indicating widespread aqueous alteration of the crust. Many of these locales exhibit sulfates, which in some cases imply acidic fluids. At present, there are few constraints on the paleoenvironmental conditions that existed during formation of the widespread and diverse classes of secondary minerals on Mars. We investigated hydrothermal systems at three active acidic volcanic systems in Nicaragua, including Cerro Negro, Momotombo, and Telica. The recently erupted materials are similar in composition to the Martian crust and are undergoing extensive acid-sulfate alteration predominately in gas-dominated settings (fumaroles). We characterized the secondary mineralogy and local variables, including temperature, pH, rock and gas composition, and fluid-rock ratio. We find that these environmental parameters exhibit strong controls on the alteration mineralogy. The environments studied include pH that ranged from -1 to 6, temperatures from ambient to hundreds of degrees Celsius, and fumaroles to hot springs. The hottest and most acidic systems contained sulfur, silica, and minor gypsum, while moderately acidic and cooler fumaroles included abundant silica, gypsum and other hydrated sulfates, and phyllosilicates. A setting with a higher fluid-rock ratio but similar temperature and acidity was dominated by phyllosilicates and, to a lesser degree, sulfates. The characterization of aqueous alteration of basalts under a variety of environmental conditions provides a conceptual framework for interpretation of similar relic environments on Mars. Finally, while identification of phyllosilicates on Mars is generally thought to require neutral to alkaline fluids, we documented significant formation of these minerals in the acidic volcanic systems.

  16. Systems solutions by lactic acid bacteria: from paradigms to practice

    PubMed Central

    2011-01-01

    Lactic acid bacteria are among the powerhouses of the food industry, colonize the surfaces of plants and animals, and contribute to our health and well-being. The genomic characterization of LAB has rocketed and presently over 100 complete or nearly complete genomes are available, many of which serve as scientific paradigms. Moreover, functional and comparative metagenomic studies are taking off and provide a wealth of insight in the activity of lactic acid bacteria used in a variety of applications, ranging from starters in complex fermentations to their marketing as probiotics. In this new era of high throughput analysis, biology has become big science. Hence, there is a need to systematically store the generated information, apply this in an intelligent way, and provide modalities for constructing self-learning systems that can be used for future improvements. This review addresses these systems solutions with a state of the art overview of the present paradigms that relate to the use of lactic acid bacteria in industrial applications. Moreover, an outlook is presented of the future developments that include the transition into practice as well as the use of lactic acid bacteria in synthetic biology and other next generation applications. PMID:21995776

  17. Polyethylene glycol plus an oral sulfate solution as a bowel cleansing regimen for colon capsule endoscopy: a prospective, single-arm study in healthy volunteers

    PubMed Central

    Peled, Ravit

    2015-01-01

    Objectives: As with colonoscopy, adequate bowel cleansing is essential prior to colon capsule endoscopy (CCE). Because CCE requires that the capsule traverse the entire gastrointestinal tract during the examination, laxative ‘boosters’ are used. The objective of this prospective, single-center, single-arm study was to evaluate the safety of a bowel preparation consisting of polyethylene glycol (PEG) plus an oral sulfate solution. Methods: Subjects were healthy volunteers aged 50–75 years old with normal baseline serum chemistry. The bowel preparation consisted of 4 Senna tablets, 4 liters of PEG (split dose), 10 mg metoclopramide, 2 oral sulfate solution boosters (6 oz. and 3 oz.), and 10 mg bisacodyl. Serum chemistry was performed at baseline, following PEG intake, 24 hours after bisacodyl administration, and at 7 days post procedure (in subjects with abnormal 24 hour results). The primary endpoints were the percentage of subjects with a clinically significant change in serum chemistry at the last test and the adverse event (AE) rate. Results: A total of 25 subjects were enrolled. The serum chemistry was normal in all subjects at the final evaluation. One subject showed a slight elevation in creatinine (1.08 mg/dl 7 days post procedure from 0.84 mg/dl at baseline), deemed not clinically significant. Another subject had a transient elevation in serum creatinine (from 1.01 mg/dl at baseline to 1.45 mg/dl at 24 hours after the bowel preparation); values returned to near baseline at 7 days post procedure (1.06 mg/dl). There were no serious AEs, three moderate AEs related to the bowel preparation (nausea, headache, elevated creatinine) and two mild unrelated AEs (chills, abdominal cramping). Conclusions: A bowel cleansing regimen of PEG plus an oral sulfate solution can be used in healthy volunteers. These data provide support for the continued study of this regimen in future CCE clinical trials and in medical practice. PMID:26327914

  18. Isolation and separation of transplutonium elements from other actinides on ion exchange resins from aqueous and aqueous ethanol solutions of sulfuric acid

    SciTech Connect

    Guseva, L.I.; Tikhomirova, G.S.; Stepushkina, V.V.

    1987-11-01

    The behavior of Am, Cm, Bk, Cf, Es, and other actinides, as well as Zr, on an anion exchange resin and a cation exchange resin in aqueous and aqueous alcohol solutions of sulfuric acid was investigated as a function of the concentration of various components of the solution. It was found that the presence of alcohol in sulfuric acid solutions leads to an increase in the distribution coefficients both on cation exchange resins and on anion exchange resins. The possibility of using ion exchange resins for the concentration and separation of transplutonium elements from U, Np, Pu, Zr, and other elements that form strong complexes with sulfate ions in a wide range of sulfuric acid concentrations was demonstrated.

  19. Compatibility and stability of potassium chloride and magnesium sulfate in 0.9% sodium chloride injection and 5% dextrose injeciton solutions.

    PubMed

    Quay, I; Tan, E

    2001-01-01

    The compatibility and stability of 80 mmol/L potassium chloride and 16 mmol/L magnesium sulfate in 0.9% sodium chloride injection and in 5% dextrose injection solutions at 22 deg C have been studied by means of a Beckman Clinical Chemistry Analyzer Synchron CX5 Delta. The infusions were stable for 24 hours at 22 deg C. The results from both diluents showed an average of +/-5% fluctuations in concentration. None of the samples appeared to form visible precipitation or to change in color or clarity.

  20. Simultaneous chemical oxygen demand removal, methane production and heavy metal precipitation in the biological treatment of landfill leachate using acid mine drainage as sulfate resource.

    PubMed

    Li, Yu-Long; Wang, Jin; Yue, Zheng-Bo; Tao, Wei; Yang, Hai-Bin; Zhou, Yue-Fei; Chen, Tian-Hu

    2017-03-06

    Biological treatment played an important role in the treatment of landfill leachate. In the current study, acid mine drainage (AMD) was used as a source of sulfate to strengthen the anaerobic treatment of landfill leachate. Effects of chemical oxygen demand (COD) and SO4(2-) mass concentration ratio on the decomposition of organic matter, methane production and sulfate reduction were investigated and the microbial community was analyzed using the high throughout methods. Results showed that high removal efficiency of COD, methane production and heavy metal removal was achieved when the initial COD/SO4(2-) ratio (based on mass) was set at 3.0. The relative abundance of anaerobic hydrogen-producing bacteria (Candidatus Cloacamonas) in the experimental group with the addition of AMD was significantly increased compared to the control. Abundance of hydrogenotrophic methanogens of Methanosarcina and Methanomassiliicoccus was increased. Results confirmed that AMD could be used as sulfate resource to strengthen the biological treatment of landfill leachate.

  1. Improved synthesis of glycine, taurine and sulfate conjugated bile acids as reference compounds and internal standards for ESI-MS/MS urinary profiling of inborn errors of bile acid synthesis.

    PubMed

    Donazzolo, Elena; Gucciardi, Antonina; Mazzier, Daniela; Peggion, Cristina; Pirillo, Paola; Naturale, Mauro; Moretto, Alessandro; Giordano, Giuseppe

    2017-03-11

    Bile acid synthesis defects are rare genetic disorders characterized by a failure to produce normal bile acids (BAs), and by an accumulation of unusual and intermediary cholanoids. Measurements of cholanoids in urine samples by mass spectrometry are a gold standard for the diagnosis of these diseases. In this work improved methods for the chemical synthesis of 30 BAs conjugated with glycine, taurine and sulfate were developed. Diethyl phosphorocyanidate (DEPC) and diphenyl phosphoryl azide (DPPA) were used as coupling reagents for glycine and taurine conjugation. Sulfated BAs were obtained by sulfur trioxide-triethylamine complex (SO3-TEA) as sulfating agent and thereafter conjugated with glycine and taurine. All products were characterized by NMR, IR spectroscopy and high resolution mass spectrometry (HRMS). The use of these compounds as internal standards allows an improved accuracy of both identification and quantification of urinary bile acids.

  2. Acidic and total primary sulfates: development of emission factors for major stationary combustion sources

    SciTech Connect

    Goklamy, I.M.

    1984-02-01

    This paper develops 'best estimates' of emission factors for major sources of acidic and total primary sulphates for use in the compilation of emission inventories for the eastern US, which may, in turn, be used for modelling acidic or sulphate deposition. The authors conclude that much of the existing data on primary sulphates from stationary combustion sources are probably significantly biased upward and, therefore, inappropriate for the derivation of emission factors. Existing estimates of primary sulphate emissions for these source categories are probably substantially inflated. It also concludes that for most source categories, very little confidence can be attached to the best estimates because of the paucity of data obtained from measurement techniques which are likely to be free of systematic bias.

  3. Multivariate analysis of electron detachment dissociation and infrared multiphoton dissociation mass spectra of heparan sulfate tetrasaccharides differing only in hexuronic acid stereochemistry.

    PubMed

    Oh, Han Bin; Leach, Franklin E; Arungundram, Sailaja; Al-Mafraji, Kanar; Venot, Andre; Boons, Geert-Jan; Amster, I Jonathan

    2011-03-01

    The structural characterization of glycosaminoglycan (GAG) carbohydrates by mass spectrometry has been a long-standing analytical challenge due to the inherent heterogeneity of these biomolecules, specifically polydispersity, variability in sulfation, and hexuronic acid stereochemistry. Recent advances in tandem mass spectrometry methods employing threshold and electron-based ion activation have resulted in the ability to determine the location of the labile sulfate modification as well as assign the stereochemistry of hexuronic acid residues. To facilitate the analysis of complex electron detachment dissociation (EDD) spectra, principal component analysis (PCA) is employed to differentiate the hexuronic acid stereochemistry of four synthetic GAG epimers whose EDD spectra are nearly identical upon visual inspection. For comparison, PCA is also applied to infrared multiphoton dissociation spectra (IRMPD) of the examined epimers. To assess the applicability of multivariate methods in GAG mixture analysis, PCA is utilized to identify the relative content of two epimers in a binary mixture.

  4. Acid fog Deposition of Crusts on Basaltic Tephra Deposits in the Sand Wash Region of Kilauea Volcano: A Possible Mechanism for Siliceous-Sulfatic Crusts on Mars

    NASA Astrophysics Data System (ADS)

    Schiffman, P.; Zierenberg, R.; Marks, N.; Bishop, J. L.

    2004-12-01

    Although the presence of sulfate minerals in martian outcrops may imply the prior existence of standing bodies of surface water, in terrestrial volcanic settings, sulfatic alteration may also occur above the water table within the vadose zone. On the summit of Kilauea volcano, sulfur dioxide, which is continuously emitted from Halemaumau crater and rapidly sequestered into sulfuric acid-rich aerosol entrained in the prevailing trade winds, is subsequently precipitated as acid-fog immediately downwind from the caldera in the Kau Desert. The characteristic pH of surface tephra deposits is < 4.0 in Sand Wash, a region of continuous, acidic aerosol fall-out immediately SW of the caldera. The upper portion of the Keanakakoi Ash tephra in Sand Wash, deposited in the late 18th century, has a ubiquitous, 0.1-0.2 mm-thick coating of amorphous silica. Conversely, vertical walls of unconsolidated tephra, exposed within small, dry gullies eroded into the ca. 3-4 m-thick Keanakakoi section at Sand Wash, are coated with ca. 0.5-1.0 mm-thick, mixed amorphous silica and jarosite-bearing crusts. Since these crusts are denuded from their outcrops during ephemeral, but probably annual flooding events in Sand Wash, we believe that they must accumulate rapidly. These crusts are apparently formed via an evaporative mechanism whereby acidic pore fluids, circulating in the upper few m's within the highly porous tephra, are wicked towards the walls of the gullies. Geochemical modeling of the crust-forming process implies that the sulfate formation via evaporation occurs subsequent to minimal interaction of acidic pore fluids with the basaltic tephra. This also suggests that the cycle from acid-fog fall-out to precipitation of the siliceous-sulfatic crusts must occur quite rapidly. Production of siliceous-sulfatic crusts via acid-fog alteration may also be occurring on Mars. The occurrence of evaporitic sulfate and silica at Sand Wash in Kilauea may serve as an example of how the jarosite

  5. Strategy Approach for Direct Enantioseparation of Hyoscyamine Sulfate and Zopiclone on a Chiral αl-Acid Glycoprotein Column and Determination of Their Eutomers: Thermodynamic Study of Complexation.

    PubMed

    Zaazaa, Hala E; Salama, Nahla N; Abd El Halim, Lobna M; Salem, Maissa Y; Abd El Fattah, Laila E

    2016-01-01

    Rapid and simple isocratic high-performance liquid chromatographic methods with UV detection were developed and validated for the direct resolution of racemic mixtures of hyoscyamine sulfate and zopiclone. The method involved the use of αl -acid glycoprotein (AGP) as chiral stationary phase. The stereochemical separation factor (ά) and the stereochemical resolution factor (Rs ) obtained were 1.29 and 1.60 for hyoscyamine sulfate and 1.47 and 2.45 for zopiclone, respectively. The method was used for determination of chiral switching (eutomer) isomers: S-hyoscyamine sulfate and eszopiclone. Several mobile phase parameters were investigated for controlling enantioselective retention and resolution on the chiral AGP column. The influence of mobile phase, concentration and type of uncharged organic modifier, ionic strength, and column temperature on enantioselectivity were studied. Calibration curves were linear in the ranges of 1-10 µg mL(-1) and 0.5-5 µg mL(-1) for S-hyoscyamine sulfate and eszopiclone, respectively. The method is specific and sensitive, with lower limits of detection and quantifications of 0.156, 0.515 and 0.106, 0.349 for S-hyoscyamine sulfate and eszopiclone, respectively. The method was used to identify quantitatively the enantiomers profile of the racemic mixtures of the studied drugs in their pharmaceutical preparations. Thermodynamic studies were performed to calculate the enthalpic ΔH and entropic ΔS terms. The results showed that enantiomer separation of the studied drugs were an enthalpic process.

  6. Solution and gas-phase acidities of all-trans (all-E) retinoic acid: an experimental and computational study.

    PubMed

    Abboud, José-Luis M; Koppel, Ilmar A; Uggerud, Einar; Leito, Ivo; Koppel, Ivar; Sekiguchi, Osamu; Kaupmees, Karl; Saame, Jaan; Kütt, Karl; Mishima, Masaaki

    2015-07-27

    Retinoic acid is of fundamental biological importance. Its acidity was determined in the gas phase and in acetonitrile solution by means of mass spectrometry and UV/Vis spectrophotometry, respectively. The intrinsic acidity is slightly higher than that of benzoic acid. In solution, the situation is opposite. The experimental systems were described theoretically applying quantum chemical methods (wave function theory and density functional theory). This allowed the determination of the molecular structure of the acid and its conjugate base, both in vacuo and in solution, and for computational estimates of its acidity in both phases.

  7. Nanomechanical Behavior of Human Molars Soaked in Slight Acid Solutions

    NASA Astrophysics Data System (ADS)

    Fang, Te-Hua; Chang, Win-Jin; Kang, Shao-Hui; Chu, Chia-Chun

    This paper studied the mechanical and chemical properties of hydroxyl apatite (HA) crystal structure in the teeth when human molars were soaked in slight acid solution. First, we soaked the ground and polished molars respectively in the liquor of 30 wt.% H2CO3 and the liquor of 30 wt.% H2O2 for 10, 20, or 60 minutes. Next, we used a nanoindenter to measure the hardness and Young's modulus. Finally, we used a scanning electron microscope (SEM) coupled with energy dispersive spectroscopy (EDS) to analyze the variation of Ca, P and Na in teeth, a high resolution transmitting electron microscope (HRTEM) to observe the arrangement of crystallization phase of HA, and X-ray diffraction (XRD) to analyze the crystallinity of the hexagonal phase of HA. The results showed that the demineralization phenomenon of the calcium-phosphorous compound in teeth made the teeth reduce sharply in hardness and Young's modulus after they were soaked in the two slight acid solutions for 10 minutes, but the re-mineralization phenomenon made the hardness and Young's modulus ascend gradually when the time lasted longer. With the same period of time, the teeth soaked in H2CO3 were lower in the hardness and Young's modulus than that in H2O2.

  8. Electrocatalytic hydrogenation of 5-hydroxymethylfurfural in acidic solution.

    PubMed

    Kwon, Youngkook; Birdja, Yuvraj Y; Raoufmoghaddam, Saeed; Koper, Marc T M

    2015-05-22

    Electrocatalytic hydrogenation of 5-hydroxymethylfurfural (HMF) is studied on solid metal electrodes in acidic solution (0.5 M H2 SO4 ) by correlating voltammetry with on-line HPLC product analysis. Three soluble products from HMF hydrogenation are distinguished: 2,5-dihydroxymethylfuran (DHMF), 2,5-dihydroxymethyltetrahydrofuran (DHMTHF), and 2,5-dimethyl-2,3-dihydrofuran (DMDHF). Based on the dominant reaction products, the metal catalysts are divided into three groups: (1) metals mainly forming DHMF (Fe, Ni, Cu, and Pb), (2) metals forming DHMF and DMDHF depending on the applied potentials (Co, Ag, Au, Cd, Sb, and Bi), and (3) metals forming mainly DMDHF (Pd, Pt, Al, Zn, In, and Sb). Nickel and antimony are the most active catalysts for DHMF (0.95 mM cm(-2) at ca. -0.35 VRHE and -20 mA cm(-2) ) and DMDHF (0.7 mM cm(-2) at -0.6 VRHE and -5 mA cm(-2) ), respectively. The pH of the solution plays an important role in the hydrogenation of HMF: acidic condition lowers the activation energy for HMF hydro-genation and hydrogenates the furan ring further to tetrahydrofuran.

  9. Mechanics, degradability, bioactivity, in vitro, and in vivo biocompatibility evaluation of poly(amino acid)/hydroxyapatite/calcium sulfate composite for potential load-bearing bone repair.

    PubMed

    Fan, Xiaoxia; Ren, Haohao; Luo, Xiaoman; Wang, Peng; Lv, Guoyu; Yuan, Huipin; Li, Hong; Yan, Yonggang

    2016-03-01

    A ternary composite of poly(amino acid), hydroxyapatite, and calcium sulfate (PAA/HA/CS) was prepared using in situ melting polycondensation method and evaluated in terms of mechanical strengths, in vitro degradability, bioactivity, as well as in vitro and in vivo biocompatibility. The results showed that the ternary composite exhibited a compressive strength of 147 MPa, a bending strength of 121 MPa, a tensile strength of 122 MPa, and a tensile modulus of 4.6 GPa. After immersion in simulated body fluid, the compressive strength of the composite decreased from 147 to 98 MPa for six weeks and the bending strength decreased from 121 to 75 MPa for eight weeks, and both of them kept stable in the following soaking period. The composite could be slowly degraded with 7.27 wt% loss of initial weight after soaking in phosphate buffered solution for three weeks when started to keep stable weight in the following days. The composite was soaked in simulated body fluid solution and the hydroxyapatite layer, as flower-like granules, formed on the surface of the composite samples, showing good bioactivity. Moreover, it was found that the composite could promote proliferation of MG-63 cells, and the cells with normal phenotype extended and spread well on the composite surface. The implantation of the composite into the ulna of sheep confirmed that the composite was biocompatible and osteoconductive in vivo, and offered the PAA/HA/CS composite promising material for load-bearing bone substitutes for clinical application.

  10. Precipitation of sodium acid urate from electrolyte solutions

    NASA Astrophysics Data System (ADS)

    Füredi-Milhofer, Helga; Babić-Ivaniĉić, Vesna; Milat, Ognjen; Brown, Walter E.; Gregory, Thomas M.

    1987-07-01

    The precipitation of soduim urate from solutions containing uric acid, soduim hydroxide, hydrochloric acid, sodium chloride and water was investigated at constant pH (7.5±0.1) and temperature (308 K). Precipitates were observed by lights and electron microscopy and characterized by electron and X-ray diffraction. The results are presented in the form of "precipitation" and "chemical potential" diagrams, the latter giving the soduim-to-urate molar ratios of the precipitates. Two types of precipitation boundaries were observed, both of which had indicated soduim-to-urate moral ratios of 1:1. The ion activity product, (Na +)(HU -), associated with boundary I was AP I=(4.8±1.1)×10 -5 and with boundary II was with boundary II was AP II=(6.5±0.4)×10 -4. The supersaturation, S, at boundary II was S=AP II/ Ksp=12.3, in which Ksp is the solubility product of soduim acid urate monohydrate. The latter precipitated as well-formed crystals at supersaturations of 12.3 and above. The ion activity product associated with boundary I is approximately equal to the solubility product of soduim acid urate monohydrate. Small amounts of several morphologically different sodium urate crystals formed in the range of supersaturations (1≤ S≤12.3). Crystals formed in this range may include the monohydrate of sodium acid urate and possibly a higher hydrate. The findings have relevance to pathological renal stone formation and gouty arthritis.

  11. Detection and Characterization of Ultrafine Fe-as-pb Colloids In Acid Rock Drainage Solution From An Ore Mine

    NASA Astrophysics Data System (ADS)

    Zänker, H.; Moll, H.; Richter, W.; Brendler, V.; Hennig, C.; Reich, T.; Kluge, A.; Hüttig, G.

    The processes of sulfide oxidation, water acidification and water mineralization in abandoned ore mines are closely associated with the existence of gangue fissures in the host rock that contain clay minerals and finely-divided sulfide ores. These fissures release highly mineralized, red-colored acid rock drainage (ARD) solutions which can be collected from pools in front of the fissures. ARD solution from an abandoned Zn-Pb-A g mine at Freiberg, Germany, (pH 2.7, sulfate concentration 411 mmol/l, Fe concentration 93,5 mmol/l) was nvestigated by photon correlation i spectroscopy, centrifugation, filtration, ultrafiltration, scanning electron microscopy, ICP-MS, AAS, ion chromatography, TOC analysis and X-ray absorption fine structure (EXAFS) spectroscopy. The question was if this ARD solution contains colloidal particles of the lower nanometer range or if it is particle-free after the common filtration through a 450-nm filter. We found that there is a small amount (about 20 mg/l) of submicron particles of about 100 nm in size. However, the major colloidal component was shown to be a population of ultrafine particles of less than 5 nm. The concentration of these particles is about 1 g/l. They consist of Fe, As and Pb compounds. According to EXAFS spectroscopy, their most probable mineralogical composition is a mixture of hydronium jarosite (HFe3(SO4)2(OH)6) and schwertmannite (ideally Fe8O8(OH)6SO 4). We also observed the formation of a relatively coarse precipitate of a similar mineralogy in the colloidal solution over a time span of months. The ultrafine colloids are obviously an intermediate in the formation process of the long-term precipitate. The arsenic is probably bound onto the ultrafine colloidal particles as a bidentate binuclear ars enate surface complex (inner-sphere complex). However, the transformation of the colloids into the more aggregated long-term precipitate leads to the incorporation of the arsenic into the interior of the iron hydroxy sulfate

  12. Synthesis of S-linked glycosyl amino acids in aqueous solution with unprotected carbohydrates.

    PubMed

    Cohen, S B; Halcomb, R L

    2001-02-08

    [figure: see text] The cyclic sulfamidate 5 was synthesized in 60% overall yield from L-serine benzyl ester. Compound 5 reacted cleanly with the sodium thiolate salt of a variety of unprotected 1-thio sugars in aqueous buffer to afford the corresponding S-linked amino acid glycoconjugates in good yields after hydrolysis of the N-sulfates.

  13. Corrosion behavior of mild steel in acetic acid solutions

    SciTech Connect

    Singh, M.M.; Gupta, A.

    2000-04-01

    The corrosion behavior of mild steel in acetic acid (CH{sub 3}COOH) solutions was studied by weight loss and potentiostatic polarization techniques. The variation in corrosion rate of mild steel with concentrations of CH{sub 3}COOH, evaluated by weight loss and electrochemical techniques, showed marked resemblance. From both techniques, the maximum corrosion rate was observed for 20% CH{sub 3}COOH solution at all three experimental temperatures (25, 35, and 45 C). Anodic polarization curves showed active-passive behavior at each concentration, except at 80% CH{sub 3}COOH. Critical current density (i{sub c}) passive current density (I{sub n}), primary passivation potential (E{sub pp}), and potential for passivity (E{sub p}) had their highest values in 20% CH{sub 3}COOH solution. With an increase in temperature, while the anodic polarization curves shifted toward higher current density region at each concentration, the passive region became progressively less distinguishable. With the addition of sodium acetate (NaCOOCH{sub 3}) as a supporting electrolyte, the passive range was enlarged substantially. However, the transpassive region commenced at more or less the same potential. Cathodic polarization curves were almost identical irrespective of the concentration of CH{sub 3}COOH or temperature.

  14. Complex metabolism of aromatic glucosinolates in Pieris rapae caterpillars involving nitrile formation, hydroxylation, demethylation, sulfation, and host plant dependent carboxylic acid formation.

    PubMed

    Agerbirk, Niels; Olsen, Carl Erik; Poulsen, Eva; Jacobsen, Niels; Hansen, Paul Robert

    2010-02-01

    We investigated the metabolism of two chain elongated phenolic glucosinolates and the corresponding O-methyl derivatives upon ingestion by caterpillars of the butterfly Pieris rapae (L.). The glucosinolates (GSLs) were 4-hydroxyphenethylGSL, (R)-2-hydroxy-2-(4-hydroxyphenyl)ethylGSL, 4-methoxyphenethylGSL, and (R)-2-hydroxy-2-(4-methoxyphenyl)ethylGSL, variously occurring in foliage of two Arabis species: Arabis hirsuta (L.) Scop. and Arabis soyeri Reut. & Huet subsp. subcoriacea (Gren. ex Nyman) Breitstr. (Brassicaceae). Frass from caterpillars reared on each Arabis species contained two sulfated nitriles (4-sulfates of 3-(4-hydroxyphenyl)propanenitrile and 3-hydroxy-3-(4-hydroxyphenyl)propanenitrile) as apparent GSL metabolites. Comparison of glucosinolate levels in foliage and levels of sulfated nitriles in frass, and experiments with isolated GSLs spiked to crucifer foliage and ingested by P. rapae, demonstrated that phenolic GSLs and the corresponding O-methyl derivatives were metabolised to sulfated nitriles, and that metabolites lacking a beta-hydroxy group were partially hydroxylated in this position during metabolism in P. rapae. In contrast, an induction experiment did not show increased levels of beta-hydroxylated GSLs in A. soyeri plants upon caterpillar feeding. Frass contents of other putative GSL metabolites from the interaction with the two Arabis species differed significantly; caterpillars reared on A. hirsuta excreted significant amounts of four carboxylic acids (3-(4-hydroxyphenyl)propanoic acid, 3-hydroxy-3-(4-hydroxyphenyl)propanoic acid, and the corresponding 4-sulfates), which were low or absent when the caterpillars were reared on A. soyeri. The excreted carboxylic acids could be formed by hydrolysis of nitriles to carboxylic acids in caterpillar guts by an ingested nitrilase enzyme from A. hirsuta foliage; this hypothesis was supported by demonstration of 3-(4-hydroxyphenyl)propanenitrile hydrolysing nitrilase activity (E.C. 3.5.5.x) in a

  15. Conformation of poly(γ-glutamic acid) in aqueous solution.

    PubMed

    Muroga, Yoshio; Nakaya, Asami; Inoue, Atsuki; Itoh, Daiki; Abiru, Masaya; Wada, Kaori; Takada, Masako; Ikake, Hiroki; Shimizu, Shigeru

    2016-04-01

    Local conformation and overall conformation of poly(γ-DL-glutamic acid) (PγDLGA) and poly(γ-L-glutamic acid) (PγLGA) in aqueous solution was studied as a function of degree of ionization ε by (1) H-NMR, circular dichroism, and potentiometric titration. It was clarified that their local conformation is represented by random coil over an entire ε range and their overall conformation is represented by expanded random-coil in a range of ε > ε(*) , where ε(*) is about 0.3, 0.35, 0.45, and 0.5 for added-salt concentration of 0.02M, 0.05M, 0.1M, and 0.2M, respectively. In a range of ε < ε(*) , however, ε dependence of their overall conformation is significantly differentiated from each other. PγDLGA tends to aggregate intramolecularly and/or intermolecularly with decreasing ε, but PγLGA still behaves as expanded random-coil. It is speculated that spatial arrangement of adjacent carboxyl groups along the backbone chain essentially affects the overall conformation of PγGA in acidic media.

  16. Understanding barite and gypsum precipitation in upland acid-sulfate soils: An example from a Lufkin Series toposequence, south-central Texas, USA

    NASA Astrophysics Data System (ADS)

    Jennings, Debra S.; Driese, Steven G.

    2014-01-01

    Although low-temperature barite precipitation has been previously documented in soils and paleosols, pedogenic barite precipitation remains poorly understood. This study characterizes the micromorphology, elemental trends, and stable isotope geochemistry of sulfates in a barite-bearing soil (Lufkin Series) toposequence using optical microscopy, XRD, ICP-MS, and stable S and O isotope data. Synthesized data indicate that fluctuating redox processes and microbial activity resulting from epiaquatic and evaporative conditions lead to the precipitation of sulfates in the Lufkin soils. Stable sulfur and oxygen isotopes indicate that the primary source of sulfur is the partial dissolution of jarosite during microbial sulfate reduction. Barium-rich parent material provides adequate barium for barite precipitation. Barium is mobilized and concentrated in Btg horizons ~ 100-160 cm below the surface. The presence of humic acids in profiles lower on the landscape prevents barite precipitation and drives the precipitation of gypsum between saturated, anoxic conditions (November to May) and drier, more oxic conditions (May to November). Barite precipitation is a slow, punctuated process. Micromorphological data reveal that barite precipitates first along evacuated macropores and then in the adjacent matrix. In general, optimal conditions for pedogenic barite precipitation in upland wetland acid-sulfate soils are: 1) warm soil temperature that supports active sulfur-reducing and sulfur oxidizing microbes; 2) distinct wet/dry seasons that allow alternating redox conditions; 3) low-gradient landscape; 4) parent material that contains barium- and sulfur-rich constituents; and 5) a long-lived, stable landscape.

  17. Infrared optical constants of H2O ice, amorphous nitric acid solutions, and nitric acid hydrates

    NASA Technical Reports Server (NTRS)

    Toon, Owen B.; Koehler, Birgit G.; Middlebrook, Ann M.; Tolbert, Margaret A.; Jordon, Joseph

    1994-01-01

    We determined the infrared optical constants of nitric acid trihydrate, nitric acid dihydrate, nitric acid monohydrate, and solid amorphous nitric acid solutions which crystallize to form these hydrates. We have also found the infrared optical constants of H2O ice. We measured the transmission of infrared light throught thin films of varying thickness over the frequency range from about 7000 to 500/cm at temperatures below 200 K. We developed a theory for the transmission of light through a substrate that has thin films on both sides. We used an iterative Kramers-Kronig technique to determine the optical constants which gave the best match between measured transmission spectra and those calculated for a variety of films of different thickness. These optical constants should be useful for calculations of the infrared spectrum of polar stratospheric clouds.

  18. Effect of ferrous sulfate and nitrohumic acid neutralization on the leaching of metals from a combined bauxite residue.

    PubMed

    Ren, Jie; Liu, Jidong; Chen, Juan; Liu, Xiaolian; Li, Fasheng; Du, Ping

    2017-02-23

    Bauxite residue neutralization is intended to open opportunities for revegetation and reuse of the residue. Ferrous sulfate (FS) and nitrohumic acid (NA) were two kinds of materials studied for pH reduction of the residue from 10.6 to 8.3 and 8.1, respectively. The effects of FS and NA on the leaching of metals from a combined bauxite residue were investigated by using sequential and multiple extraction procedures. Neutralization with FS and NA restricted the leaching of Al, V, and Pb from the residue but promoted the leaching of Fe, Cu, Mn, and Ni, consistent with the changes in the potentially mobile fractions. With the exceptions of Pb and Ni, leaching of metals increased during a 10-day extraction period. However, the maximum leaching of Al, V, Pb, Fe, Cu, Mn, and Ni from neutralized bauxite residue were 0.46 mg/L, 59.3, 12.9, 167, 95.3, 15.5, and 14.5 μg/L, respectively, which were under the corresponding limits in the National Standard (GB/T 14848-93). Although it is necessary to consider the continued leaching of metals during neutralization, both maximum and accumulation leaching concentrations of metals from a combined bauxite residue were too low to pose a potential environmental risk.

  19. Increased Serum Hyaluronic Acid and Heparan Sulfate in Dengue Fever: Association with Plasma Leakage and Disease Severity

    PubMed Central

    Tang, Tommy Hing-Cheung; Alonso, Sylvie; Ng, Lisa Fong-Poh; Thein, Tun-Linn; Pang, Vincent Jun-Xiong; Leo, Yee-Sin; Lye, David Chien-Boon; Yeo, Tsin-Wen

    2017-01-01

    Plasma leakage is a major pathogenic mechanism of severe dengue, but the etiology remains unclear. The association between endothelial glycocalyx integrity and vascular permeability in older adults with dengue has not been evaluated. A prospective cohort study of adults with undifferentiated fever screened for dengue by RT-PCR or NS1 antigen testing was performed. Patients were assessed daily while symptomatic and at convalescence. Serum hyaluronic acid (HA), heparan sulfate (HS) and selected cytokines (TNF-α, IL-6, IL-10) were measured on enrollment and convalescence. Patients were diagnosed as dengue fever (DF, n = 30), dengue hemorrhagic fever (DHF, n = 20) and non-dengue (ND) febrile illness (n = 11). Acute HA and HS levels were significantly higher in all dengue patients compared to ND (p = 0.0033 and p = 0.0441 respectively), but not different between DF and DHF (p = 0.3426 and p = 0.9180 respectively). Enrolment HA inversely correlated with serum albumin, protein and platelets in all dengue and DHF (p < 0.05). HA and HS in all dengue patients decreased significantly at convalescence. Serum IL-10 was significantly associated with HA in all dengue patients (p = 0.002). Serum HA and HS levels were increased in adult dengue and HA was associated with markers of disease severity. Endothelial glycocalyx damage may have a role in vascular leakage in dengue. PMID:28393899

  20. Relative roles of acetic acid, dodecyl sulfate and benzotriazole in chemical mechanical and electrochemical mechanical planarization of copper

    NASA Astrophysics Data System (ADS)

    Goonetilleke, P. C.; Roy, D.

    2008-02-01

    The efficiency of chemical mechanical or electrochemical mechanical planarization (CMP or ECMP) carried out in the fabrication of integrated circuits is largely governed by the functional chemicals used in these processes. In this work, we study the individual and combined chemical and electrochemical effects of a selected set of such chemicals that can potentially support both CMP and ECMP of copper. These chemicals include acetic acid (HAc) as a complexing agent, H2O2 as an oxidizer, and ammonium dodecyl sulfate (ADS) as a dissolution inhibitor. Surface passivating effects of ADS under both CMP (open circuit) and ECMP (voltage activated) conditions are compared with those of a standard dissolution inhibitor for Cu, benzotriazole (BTAH), and the combined effects of a BTAH-ADS mixture also are explored. The experiments are performed in the absence of mechanical polishing using static and rotating Cu disc electrodes, and electro-dissolution of Cu for ECMP is activated using a voltage pulse modulation technique. A mechanism of surface reactions is proposed to describe the relative roles of HAc, H2O2, ADS and BTAH as electrolyte components for CMP and ECMP of Cu.

  1. Effects of propionic acid and of copper sulfate on the nutritional value of diets containing moldy corn for broiler chicks.

    PubMed

    Bartov, I

    1983-11-01

    Diets containing moldy corn (in which fat levels were restored or not restored by soybean oil) were supplemented with either propionic acid (PA) or copper sulfate (CS), and their nutritional value for young broiler chicks was evaluated. The fat content of a diet containing good quality grains decreased slightly, whereas that of diets containing moldy grains decreased markedly, during the 30 days of the experiment. The PA (.3%), but not CS (600 ppm), almost completely prevented this decrease. Dietary metabolizable energy (ME), retention of dry matter and protein, and the performance of the chicks fed the diet containing the moldy corn were markedly depressed. Neither CS, nor soybean oil supplementation, nor a combination of the two, counteracted these effects. Supplementation with PA however, significantly (P less than .05) increased dietary ME, increased retention of dry matter and protein, and improved performance of chicks fed the moldy grains. The combination of PA and soybean oil supplementation yielded essentially the same results as the diet containing the good corn. It is concluded, therefore, that the nutritional value of diets containing moldy grains can be completely restored if their fat content is increased in proportion to the amount lost in the moldy grains and an efficient fungistat is used.

  2. Reductions of Shiga toxin-producing Escherichia coli and Salmonella typhimurium on beef trim by lactic acid, levulinic acid, and sodium dodecyl sulfate treatments.

    PubMed

    Zhao, Tong; Zhao, Ping; Chen, Dong; Jadeja, Ravirajsinh; Hung, Yen-Con; Doyle, Michael P

    2014-04-01

    Studies were done at 21 °C to determine the bactericidal activity of lactic acid, levulinic acid, and sodium dodecyl sulfate (SDS) applied individually and in combination on Shiga toxin-producing Escherichia coli (STEC) in pure culture and to compare the efficacy of lactic acid and levulinic acid plus SDS treatments applied by spray or immersion to inactivate STEC and Salmonella (10(7) CFU/cm2) on beef trim pieces (10 by 10 by 7.5 cm). Application of 3% lactic acid for 2 min to pure cultures was shown to reduce E. coli O26:H11, O45:H2, O111:H8, O103:H2, O121:H2, O145:NM, and O157:H7 populations by 2.1, 0.4, 0.3, 1.4, 0.3, 2.1, and 1.7 log CFU/ml, respectively. Treatment with 0.5% levulinic acid plus 0.05% SDS for <1 min reduced the populations of all STEC strains to undetectable levels (>6 log/ml reduction). Beef surface temperature was found to affect the bactericidal activity of treatment with 3 % levulinic acid plus 2% SDS (LV-SDS). Treating cold (4 °C) beef trim with LV-SDS at 21, 62, or 81 °C for 30 s reduced E. coli O157:H7 by 1.0, 1.1, or 1.4 log CFU/cm2, respectively, whereas treating beef trim at 8 °C with LV-SDS at 12 °C for 0.1, 1, 3, or 5 min reduced E. coli O157:H7 by 1.4, 2.4, 2.5, or 3.3 log CFU/cm(2), respectively. Spray treatment of beef trim at 4 °C with 5 % lactic acid only reduced the E. coli O157:H7 population by 1.3 log CFU/cm2. Treating beef trim at 8 °C with LV-SDS for 1, 2, or 3 min reduced Salmonella Typhimurium by 2.1, 2.6, and >5.0 log CFU/cm2, respectively. Hand massaging the treated beef trim substantially reduced contamination of both pathogens, with no detectable E. coli O157:H7 or Salmonella Typhimurium (<5 CFU/cm2) on beef trim pieces treated with LV-SDS. Reduction of E. coli O157:H7 and Salmonella Typhimurium populations was enhanced, but bactericidal activity was affected by the meat temperature.

  3. The solvent effect on the acidities of haloacetic acids in aqueous solution. A RISM-SCF study

    NASA Astrophysics Data System (ADS)

    Kawata, Masaaki; Ten-no, Seiichiro; Kato, Shigeki; Hirata, Fumio

    1995-06-01

    The acidities of acetic, fluoracetic and chloroacetic acids in aqueous solution are calculated by means of the ab initio method combined with the reference interaction site method in the statistical mechanics of molecular liquids (the RISM-SCF method). The inversion in the order of acidities experimentally observed when a series of haloacetic acids is immersed into aqueous solution is reproduced. It is shown that the inversion is caused by competition between substitution and solvation effects. The solvation effect is discussed in molecular detail in terms of the charge distribution of the solute and the solute-solvent radial distribution functions.

  4. The extraction of actinides from nitric acid solutions with diamides of dipicolinic acid

    NASA Astrophysics Data System (ADS)

    Lapka, Joseph L.; Paulenova, Alena; Alyapyshev, Mikhail Yu; Babain, Vasiliy A.; Law, Jack D.; Herbst, R. Scott

    2010-03-01

    Diamides of dipicolinic acid (N,N'-diethyl-N,N'-ditolyl-dipicolinamide, EtTDPA) were synthesized and evaluated for their extraction capability for actinides. In this work the extractions of neptunium(V), protactinium(V), and thorium(IV) with EtTDPA in a polar fluorinated diluent from nitric acid were investigated. EtTDPA shows a high affinity for Th(IV) even at millimolar concentrations. Np(V) and Pa(V) are both reasonably extractable with EtTDPA; however, near saturated solutions are required to achieve appreciable distribution ratios. A comparison with previously published actinide extraction data is given.

  5. GADOLINIUM OXALATE SOLUBILITY MEASUREMENTS IN NITRIC ACID SOLUTIONS

    SciTech Connect

    Pierce, R. A.

    2012-03-12

    HB-Line will begin processing Pu solutions during FY2012 that will involve the recovery of Pu using oxalate precipitation and filtration. After the precipitation and filtration processes, the filtrate solution will be transferred from HB-Line to H-Canyon. The presence of excess oxalate and unfiltered Pu oxalate solids in these solutions create a criticality safety issue if they are sent to H-Canyon without controls in H-Canyon. One approach involves H-Canyon receiving the filtrate solution into a tank that is poisoned with soluble gadolinium (Gd). Decomposition of the oxalate will occur within a subsequent H-Canyon vessel. The receipt of excess oxalate into the H-Canyon receipt tanks has the potential to precipitate a portion of the Gd poison in the receipt tanks. Because the amount of Gd in solution determines the maximum amount of Pu solids that H-Canyon can receive, H-Canyon Engineering requested that SRNL determine the solubility of Gd in aqueous solutions of 4-10 M nitric acid (HNO{sub 3}), 4-12 g/L Gd, and 0.15-0.25 M oxalic acid (H{sub 2}C{sub 2}O{sub 4}) at 25 °C. The target soluble Gd concentration is 6 g/L. The data indicate that the target can be achieved above 6 M HNO{sub 3} and below 0.25 M H{sub 2}C{sub 2}O{sub 4}. At 25 °C, for 6 M HNO{sub 3}, 11 g/L and 7 g/L Gd are soluble in 0.15 M and 0.25 M H{sub 2}C{sub 2}O{sub 4}, respectively. In 4 M HNO{sub 3}, the Gd solubility drops significantly to 2.5 g/L and 0.8 g/L in 0.15 M and 0.25 M H{sub 2}C{sub 2}O{sub 4}, respectively. The solubility of Gd at 8-10 M HNO{sub 3} exceeds the solubility at 6 M HNO{sub 3}. The data for 4 M HNO{sub 3} showed good agreement with data in the literature. To achieve a target of 6 g/L soluble Gd in solution in the presence of 0.15-0.25 M oxalate, the HNO{sub 3} concentration must be maintained at or above 6 M HNO{sub 3}. The solubility of Gd in 4 M HNO{sub 3} with 0.15 M oxalate at 10 °C is about 1.5 g/L. For 6 M HNO{sub 3} with 0.15 M oxalate, the solubility of Gd at 10

  6. Radiolysis gases from nitric acid solutions containing HSA and HAN

    SciTech Connect

    Smith, J.R.

    1994-10-28

    The concentration of hydrogen (H{sub 2}) in the radiolytically produced off-gas from 2.76-4.25M HNO{sub 3}/PU solutions has been found to be greatly reduced in the presence of sulfamic acid (HSA) and hydroxylamine nitrate (HAN). The H{sub 2} concentration ([H{sub 2}]) is reduced from 35 percent to about 4 percent by dilution caused from an increase in the production rates of nitrogen (N{sub 2}), nitrous oxide (N{sub 2}O), and oxygen (O{sub 2}) gases. The generation rate of H{sub 2} was not affected by HSA or HAN giving a measured radiolytic yield, G(H{sub 2}), value of 0.201 molecules/100 eV for 2.765M NO{sub 3}{sup -} solution (a value of 0.213 is predicted from previous data). The G(H{sub 2}) values are dependent on the solution nitrate concentration ([NO{sub 3}{sup -}]). The generation rates of N{sub 2}, N{sub 2}O, and O{sub 2} are not dependent on the [NO{sub 3}{sup -}] in this narrow range, but are dependent on the presence of HSA and the concentration of HAN. The percentage [H{sub 2}] for the 2.5 to 3.0M NO{sub 3}{sup -} range expected in the off- from the FB-Line Pu{sup +3} Hold Tanks is conservatively estimated to be about 3.5 to 4.5 % for Pu + 3 solutions initially containing 0.023M HAN/0.165M HSA. The upper limit [H{sub 2}] may actually be about 4.1 % (4.3 % at 90 % confidence limits) but more {open_quotes}initial{close_quotes} off-gas rate data is needed at about 2.9M [NO{sub 3}{sup -}] in Pu{sup +3} solution for verification. Addition of ascorbic acid had no effect on the off-gas rate of Pu{sup +3} solutions containing HSA and NO{sub 3}{sup -} concentrations higher than those expected in the hold tanks. The maximum {open_quotes}hold time{close_quotes} for 50 grams/liter Pu{sup +3}/0.165M HSA/0.023M HAN/2.5-3.0M HNO{sub 3} solution is 20.3{+-}2.1 days. After this time the HSA initially present will become exhausted and the [H{sub 2}] will increase to 35 %. This hold time may be longer in [NO{sub 3}{sup -}] < 3.0M, but again more study is needed.

  7. Optical properties of chitosan in aqueous solution of L- and D-ascorbic acids

    NASA Astrophysics Data System (ADS)

    Malinkina, Olga N.; Shipovskaya, Anna B.; Kazmicheva, Olga F.

    2016-04-01

    The optical properties of aqueous chitosan solutions in L- and D-ascorbic acids were studied by optical rotatory dispersion and spectrophotometry. The specific optical rotation [α] of all chitosan solutions tested was positive, in contrast to aqueous solutions of the ascorbic acid enantiomers, which exhibit an inverse relationship of [α] values. Significant differences in the absolute values of [α] of the chitosan solutions at polymer-acid ratios exceeding the equimolar one were found.

  8. Uric acid, indoxyl sulfate, and methylguanidine activate bulbospinal neurons in the RVLM via their specific transporters and by producing oxidative stress.

    PubMed

    Oshima, N; Onimaru, H; Matsubara, H; Uchida, T; Watanabe, A; Takechi, H; Nishida, Y; Kumagai, H

    2015-09-24

    Patients with chronic renal failure often have hypertension, but the cause of hypertension, other than an excess of body fluid, is not well known. We hypothesized that the bulbospinal neurons in the rostral ventrolateral medulla (RVLM) are stimulated by uremic toxins in patients with chronic renal failure. To investigate whether RVLM neurons are sensitive to uremic toxins, such as uric acid, indoxyl sulfate, or methylguanidine, we examined changes in the membrane potentials (MPs) of bulbospinal RVLM neurons of Wister rats using the whole-cell patch-clamp technique during superfusion with these toxins. A brainstem-spinal cord preparation that preserved the sympathetic nervous system was used for the experiments. During uric acid, indoxyl sulfate, or methylguanidine superfusion, almost all the RVLM neurons were depolarized. To examine the transporters for these toxins on RVLM neurons, histological examinations were performed. The uric acid-, indoxyl sulfate-, and methylguanidine-depolarized RVLM neurons showed the presence of urate transporter 1 (URAT 1), organic anion transporter (OAT)1 or OAT3, and organic cation transporter (OCT)3, respectively. Furthermore, the toxin-induced activities of the RVLM neurons were suppressed by the addition of an anti-oxidation drug (VAS2870, an NAD(P)H oxidase inhibitor), and a histological examination revealed the presence of NAD(P)H oxidase (nox)2 and nox4 in these RVLM neurons. The present results show that uric acid, indoxyl sulfate, and methylguanidine directly stimulate bulbospinal RVLM neurons via specific transporters on these neurons and by producing oxidative stress. These uremic toxins may cause hypertension by activating RVLM neurons.

  9. Colominic acid inhibits the proliferation of cultured bovine aortic endothelial cells and injures their monolayers: cell density-dependent effects prevented by sulfation.

    PubMed

    Yamamoto, Chika; Morita, Yuki; Yamaguchi, Shinya; Hayashi, Toshimitsu; Kaji, Toshiyuki

    2006-01-18

    Colominic acid (CA), produced by Escherichia coli K1, is a polymer of sialic acid linked through alpha (2-->8) glycosidic linkages. Although there are several studies on the biological activities of chemically sulfated CA, the activity of CA has been incompletely understood. In the present study, we investigated the effects of CA, prepared as an alpha2,8-linked homopolymer of N-acetylneuraminic acid, on the proliferation and monolayer maintenance of bovine aortic endothelial cells in culture. The results indicate that CA potently inhibits the proliferation of sparse endothelial cells without nonspecific cell damage. The inhibitory effect of CA was markedly stronger than those of sodium spirulan and calcium spirulan, known polysaccharides that inhibit endothelial cell proliferation. On the other hand, in dense endothelial cells, CA induced nonspecific cell damage and markedly injured the monolayer. These results indicate that CA has two distinct effects on vascular endothelial cells: one is the inhibition of proliferation when the cell density is low, and the other is the nonspecific cytotoxicity when the cell density is high. Interestingly, these cell density-dependent effects of CA could be prevented by sulfation of the CA chains. Therefore, it is concluded that CA not only inhibits the proliferation of sparse endothelial cells without nonspecific cell damage but also injures dense cells in a monolayer by nonspecific cytotoxicity, which can be prevented by sulfation of the polysaccharide.

  10. Theoretical comparison of p-nitrophenyl phosphate and sulfate hydrolysis in aqueous solution: implications for enzyme-catalyzed sulfuryl transfer.

    PubMed

    Kamerlin, Shina Caroline Lynn

    2011-11-18

    Both phosphoryl and sulfuryl transfers are ubiquitous in biology, being involved in a wide range of processes, ranging from cell division to apoptosis. Additionally, it is becoming increasingly clear that enzymes that can catalyze phosphoryl transfer can often cross-catalyze sulfuryl transfer (and vice versa). However, while there have been extensive experimental and theoretical studies performed on phosphoryl transfer, the body of available research on sulfuryl transfer is comparatively much smaller. The present work presents a direct theoretical comparison of p-nitrophenyl phosphate and sulfate monoester hydrolysis, both of which are considered prototype systems for probing phosphoryl and sulfuryl transfer, respectively. Specifically, free energy surfaces have been generated using density functional theory, by initial geometry optimization in PCM using the 6-31+G* basis set and the B3LYP density functional, followed by single-point calculations using the larger 6-311+G** basis set and the COSMO continuum model. The resulting surfaces have been then used to identify the relevant transition states, either by further unconstrained geometry optimization or from the surface itself where possible. Additionally, configurational entropies were evaluated using a combination of the quasiharmonic approximation and the restraint release approach and added to the calculated activation barriers as a correction. Finally, the overall activation entropy was estimated by approximating the solvent contribution to the total activation entropy using the Langevin dipoles solvation model. We have reproduced both the experimentally observed activation barriers and the observed trend in the activation entropies with reasonable accuracy, as well as providing a comparison of calculated and observed (15)N and (18)O kinetic isotope effects. We demonstrate that, counterintuitively, the hydrolysis of the p-nitrophenyl sulfate proceeds through a more expansive pathway than its phosphate

  11. Trace metal biogeochemistry in mangrove ecosystems: a comparative assessment of acidified (by acid sulfate soils) and non-acidified sites.

    PubMed

    Nath, Bibhash; Birch, Gavin; Chaudhuri, Punarbasu

    2013-10-01

    The generation of acidity and subsequent mobilization of toxic metals induced by acid sulfate soils (ASSs) are known to cause severe environmental damage to many coastal wetlands and estuaries of Australia and worldwide. Mangrove ecosystems serve to protect coastal environments, but are increasingly threatened from such ASS-induced acidification due to variable hydrological conditions (i.e., inundation-desiccation cycles). However, the impact of such behaviors on trace metal distribution, bio-availability and accumulation in mangrove tissues, i.e., leaves and pneumatophores, are largely unknown. In this study, we examined how ASS-induced acidifications controlled trace metal distribution and bio-availability in gray mangrove (Avicennia marina) soils and in tissues in the Kooragang wetland, New South Wales, Australia. We collected mangrove soils, leaves and pneumatophores from a part of the wetland acidified from ASS (i.e., an affected site) for detailed biogeochemical studies. The results were compared with samples collected from a natural intertidal mangrove forest (i.e., a control site) located within the same wetland. Soil pH (mean: 5.90) indicated acidic conditions in the affected site, whereas pH was near-neutral (mean: 7.17) in the control site. The results did not show statistically significant differences in near-total and bio-available metal concentrations, except for Fe and Mn, between affected and control sites. Iron concentrations were significantly (p values≤0.001) greater in the affected site, whereas Mn concentrations were significantly (p values≤0.001) greater in the control site. However, large proportions of near-total metals were potentially bio-available in control sites. Concentrations of Fe and Ni were significantly (p values≤0.001) greater in leaves and pneumatophores of the affected sites, whereas Mn, Cu, Pb and Zn were greater in control sites. The degree of metal bio-accumulation in leaves and pneumatophores suggest contrasting

  12. Theoretical study on the reactivity of sulfate species with hydrocarbons

    USGS Publications Warehouse

    Ma, Q.; Ellis, G.S.; Amrani, A.; Zhang, T.; Tang, Y.

    2008-01-01

    The abiotic, thermochemically controlled reduction of sulfate to hydrogen sulfide coupled with the oxidation of hydrocarbons, is termed thermochemical sulfate reduction (TSR), and is an important alteration process that affects petroleum accumulations in nature. Although TSR is commonly observed in high-temperature carbonate reservoirs, it has proven difficult to simulate in the laboratory under conditions resembling nature. The present study was designed to evaluate the relative reactivities of various sulfate species in order to provide greater insight into the mechanism of TSR and potentially to fill the gap between laboratory experimental data and geological observations. Accordingly, quantum mechanics density functional theory (DFT) was used to determine the activation energy required to reach a potential transition state for various aqueous systems involving simple hydrocarbons and different sulfate species. The entire reaction process that results in the reduction of sulfate to sulfide is far too complex to be modeled entirely; therefore, we examined what is believed to be the rate limiting step, namely, the reduction of sulfate S(VI) to sulfite S(IV). The results of the study show that water-solvated sulfate anions SO42 - are very stable due to their symmetrical molecular structure and spherical electronic distributions. Consequently, in the absence of catalysis, the reactivity of SO42 - is expected to be extremely low. However, both the protonation of sulfate to form bisulfate anions (HSO4-) and the formation of metal-sulfate contact ion-pairs could effectively destabilize the sulfate molecular structure, thereby making it more reactive. Previous reports of experimental simulations of TSR generally have involved the use of acidic solutions that contain elevated concentrations of HSO4- relative to SO42 -. However, in formation waters typically encountered in petroleum reservoirs, the concentration of HSO4- is likely to be significantly lower than the levels

  13. Theoretical study on the reactivity of sulfate species with hydrocarbons

    NASA Astrophysics Data System (ADS)

    Ma, Qisheng; Ellis, Geoffrey S.; Amrani, Alon; Zhang, Tongwei; Tang, Yongchun

    2008-09-01

    The abiotic, thermochemically controlled reduction of sulfate to hydrogen sulfide coupled with the oxidation of hydrocarbons, is termed thermochemical sulfate reduction (TSR), and is an important alteration process that affects petroleum accumulations in nature. Although TSR is commonly observed in high-temperature carbonate reservoirs, it has proven difficult to simulate in the laboratory under conditions resembling nature. The present study was designed to evaluate the relative reactivities of various sulfate species in order to provide greater insight into the mechanism of TSR and potentially to fill the gap between laboratory experimental data and geological observations. Accordingly, quantum mechanics density functional theory (DFT) was used to determine the activation energy required to reach a potential transition state for various aqueous systems involving simple hydrocarbons and different sulfate species. The entire reaction process that results in the reduction of sulfate to sulfide is far too complex to be modeled entirely; therefore, we examined what is believed to be the rate limiting step, namely, the reduction of sulfate S(VI) to sulfite S(IV). The results of the study show that water-solvated sulfate anions SO42- are very stable due to their symmetrical molecular structure and spherical electronic distributions. Consequently, in the absence of catalysis, the reactivity of SO42- is expected to be extremely low. However, both the protonation of sulfate to form bisulfate anions ( HSO4-) and the formation of metal-sulfate contact ion-pairs could effectively destabilize the sulfate molecular structure, thereby making it more reactive. Previous reports of experimental simulations of TSR generally have involved the use of acidic solutions that contain elevated concentrations of HSO4- relative to SO42-. However, in formation waters typically encountered in petroleum reservoirs, the concentration of HSO4- is likely to be significantly lower than the levels

  14. Incorporation of Np(V) and U(VI) in Carbonate and Sulfate Minerals Crystallized from Aqueous Solution

    SciTech Connect

    Balboni, Enrica; Morrison, Jessica M.; Wang, Zheming; Engelhard, Mark H.; Burns, Peter C.

    2015-02-15

    The neptunyl Np(V)O2 + and uranyl U(VI)O2 2+ ions are soluble in groundwater, although their interaction with minerals in the subsurface may impact their mobility. One mechanism for the immobilization of actinyl ions in the subsurface is coprecipitation in low-temperature minerals that form naturally, or that are induced to form as part of a remediation strategy. Important differences in the crystal-chemical behavior of the Np(V) neptunyl and U(VI) uranyl ions suggest their behavior towards incorporation into growing crystals may differ significantly. Using a selection of low temperature minerals synthesized in aqueous systems under ambient conditions, this study examines the factors that impact the structural incorporation of the Np(V) neptunyl and U(VI) uranyl ions in carbonate and sulfate minerals.

  15. Uptake of ozone to mixed sodium bromide/ citric acid solutions

    NASA Astrophysics Data System (ADS)

    Lee, Ming-Tao; Steimle, Emilie; Bartels-Rausch, Thorsten; Kato, Shunsuke; Lampimäki, Markus; Brown, Matthew; van Bokhoven, Jeroen; Nolting, Frithjof; Kleibert, Armin; Türler, Andreas; Ammann, Markus

    2013-04-01

    Sea-salt solution - air interfaces play an important role in the chemistry of the marine boundary layer. The reaction of ozone (O3) with bromide is of interest in the context of formation of photolabile halogens (Br2, BrCl) in the marine boundary layer. Recent experiments have suggested that the bromide oxidation rate is related to the surface concentration of bromide [1] and inversely related to the gas phase concentration of O3, an indication for a precursor mediated reaction at the surface [2]. So far, the effect of organics (such as those occurring at the ocean surface or in marine aerosols) on the reaction of O3 with bromide aerosols has not been studied yet. In our study we investigate the uptake kinetics of O3 to a mixed solution of sodium bromide (NaBr) and citric acid (CA), which represents highly oxidized organic compounds present in the environment, with a well-established coated wall flow tube technique, which leads to exposure of the film to O3 allowing the heterogeneous reactions to take place and the loss of O3 being measured. The results indicate that the uptake of O3 to the films with the higher bromide concentrations (0.34M and 4M) is independent of the gas phase concentration and roughly consistent with uptake limited by reaction in the bulk. For the lower bromide concentration (84mM), however, we observe a trend of the uptake coefficient to decrease with increasing O3 concentration, indicating an increasing importance of a surface reaction. In an attempt to constrain the kinetic data, we employed X-ray photoelectron spectroscopy (XPS) to get insight into the surface composition of the aqueous solution - air interface. Previous XPS studies have shown that halide ion concentrations are enhanced at the aqueous solution air interface [3-4], which likely promotes the surface reactions of bromide or iodide with O3. A first XPS study of ternary solutions of KI with butanol indicated the importance of specific interactions of the cation with the alcohol

  16. Mercury methylation in Sphagnum moss mats and its association with sulfate-reducing bacteria in an acidic Adirondack forest lake wetland.

    PubMed

    Yu, Ri-Qing; Adatto, Isaac; Montesdeoca, Mario R; Driscoll, Charles T; Hines, Mark E; Barkay, Tamar

    2010-12-01

    Processes leading to the bioaccumulation of methylmercury (MeHg) in northern wetlands are largely unknown. We have studied various ecological niches within a remote, acidic forested lake ecosystem in the southwestern Adirondacks, NY, to discover that mats comprised of Sphagnum moss were a hot spot for mercury (Hg) and MeHg accumulation (190.5 and 18.6 ng g⁻¹ dw, respectively). Furthermore, significantly higher potential methylation rates were measured in Sphagnum mats as compared with other sites within Sunday Lake's ecosystem. Although MPN estimates showed a low biomass of sulfate-reducing bacteria (SRB), 2.8 × 10⁴ cells mL⁻¹ in mat samples, evidence consisting of (1) a twofold stimulation of potential methylation by the addition of sulfate, (2) a significant decrease in Hg methylation in the presence of the sulfate reduction inhibitor molybdate, and (3) presence of dsrAB-like genes in mat DNA extracts, suggested that SRB were involved in Hg methylation. Sequencing of dsrB genes indicated that novel SRB, incomplete oxidizers including Desulfobulbus spp. and Desulfovibrio spp., and syntrophs dominated the sulfate-reducing guild in the Sphagnum mos