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Sample records for high sulfur trioxide

  1. An Aerosol Condensation Model for Sulfur Trioxide

    SciTech Connect

    Grant, K E

    2008-02-07

    This document describes a model for condensation of sulfuric acid aerosol given an initial concentration and/or source of gaseous sulfur trioxide (e.g. fuming from oleum). The model includes the thermochemical effects on aerosol condensation and air parcel buoyancy. Condensation is assumed to occur heterogeneously onto a preexisting background aerosol distribution. The model development is both a revisiting of research initially presented at the Fall 2001 American Geophysical Union Meeting [1] and a further extension to provide new capabilities for current atmospheric dispersion modeling efforts [2]. Sulfuric acid is one of the most widely used of all industrial chemicals. In 1992, world consumption of sulfuric acid was 145 million metric tons, with 42.4 Mt (mega-tons) consumed in the United States [10]. In 2001, of 37.5 Mt consumed in the U.S., 74% went into producing phosphate fertilizers [11]. Another significant use is in mining industries. Lawuyi and Fingas [7] estimate that, in 1996, 68% of use was for fertilizers and 5.8% was for mining. They note that H{sub 2}SO{sub 4} use has been and should continue to be very stable. In the United States, the elimination of MTBE (methyl tertiary-butyl ether) and the use of ethanol for gasoline production are further increasing the demand for petroleum alkylate. Alkylate producers have a choice of either a hydrofluoric acid or sulfuric acid process. Both processes are widely used today. Concerns, however, over the safety or potential regulation of hydrofluoric acid are likely to result in most of the growth being for the sulfuric acid process, further increasing demand [11]. The implication of sulfuric acid being a pervasive industrial chemical is that transport is also pervasive. Often, this is in the form of oleum tankers, having around 30% free sulfur trioxide. Although sulfuric acid itself is not a volatile substance, fuming sulfuric acid (referred to as oleum) is [7], the volatile product being sulfur trioxide

  2. Globins Scavenge Sulfur Trioxide Anion Radical*

    PubMed Central

    Gardner, Paul R.; Gardner, Daniel P.; Gardner, Alexander P.

    2015-01-01

    Ferrous myoglobin was oxidized by sulfur trioxide anion radical (STAR) during the free radical chain oxidation of sulfite. Oxidation was inhibited by the STAR scavenger GSH and by the heme ligand CO. Bimolecular rate constants for the reaction of STAR with several ferrous globins and biomolecules were determined by kinetic competition. Reaction rate constants for myoglobin, hemoglobin, neuroglobin, and flavohemoglobin are large at 38, 120, 2,600, and ≥ 7,500 × 106 m−1 s−1, respectively, and correlate with redox potentials. Measured rate constants for O2, GSH, ascorbate, and NAD(P)H are also large at ∼100, 10, 130, and 30 × 106 m−1 s−1, respectively, but nevertheless allow for favorable competition by globins and a capacity for STAR scavenging in vivo. Saccharomyces cerevisiae lacking sulfite oxidase and deleted of flavohemoglobin showed an O2-dependent growth impairment with nonfermentable substrates that was exacerbated by sulfide, a precursor to mitochondrial sulfite formation. Higher O2 exposures inactivated the superoxide-sensitive mitochondrial aconitase in cells, and hypoxia elicited both aconitase and NADP+-isocitrate dehydrogenase activity losses. Roles for STAR-derived peroxysulfate radical, superoxide radical, and sulfo-NAD(P) in the mechanism of STAR toxicity and flavohemoglobin protection in yeast are suggested. PMID:26381408

  3. Globins Scavenge Sulfur Trioxide Anion Radical.

    PubMed

    Gardner, Paul R; Gardner, Daniel P; Gardner, Alexander P

    2015-11-06

    Ferrous myoglobin was oxidized by sulfur trioxide anion radical (STAR) during the free radical chain oxidation of sulfite. Oxidation was inhibited by the STAR scavenger GSH and by the heme ligand CO. Bimolecular rate constants for the reaction of STAR with several ferrous globins and biomolecules were determined by kinetic competition. Reaction rate constants for myoglobin, hemoglobin, neuroglobin, and flavohemoglobin are large at 38, 120, 2,600, and ≥ 7,500 × 10(6) m(-1) s(-1), respectively, and correlate with redox potentials. Measured rate constants for O2, GSH, ascorbate, and NAD(P)H are also large at ∼100, 10, 130, and 30 × 10(6) m(-1) s(-1), respectively, but nevertheless allow for favorable competition by globins and a capacity for STAR scavenging in vivo. Saccharomyces cerevisiae lacking sulfite oxidase and deleted of flavohemoglobin showed an O2-dependent growth impairment with nonfermentable substrates that was exacerbated by sulfide, a precursor to mitochondrial sulfite formation. Higher O2 exposures inactivated the superoxide-sensitive mitochondrial aconitase in cells, and hypoxia elicited both aconitase and NADP(+)-isocitrate dehydrogenase activity losses. Roles for STAR-derived peroxysulfate radical, superoxide radical, and sulfo-NAD(P) in the mechanism of STAR toxicity and flavohemoglobin protection in yeast are suggested.

  4. EMISSIONS OF SULFUR TRIOXIDE FROM COAL-FIRED POWER PLANTS

    EPA Science Inventory

    Emissions of sulfur trioxide (SO3) are a key component of plume opacity and acid deposition. Consequently, these emissions need to be low enough not to cause opacity violations and acid deposition. Generally, a small fraction of sulfur in coal is converted to SO3 in coal-fired co...

  5. Emissions of sulfur trioxide from coal-fired power plants.

    PubMed

    Srivastava, R K; Miller, C A; Erickson, C; Jambhekar, R

    2004-06-01

    Emissions of sulfur trioxide (SO3) are a key component of plume opacity and acid deposition. Consequently, these emissions need to be low enough to not cause opacity violations and acid deposition. Generally, a small fraction of sulfur (S) in coal is converted to SO3 in coal-fired combustion devices such as electric utility boilers. The emissions of SO3 from such a boiler depend on coal S content, combustion conditions, flue gas characteristics, and air pollution devices being used. It is well known that the catalyst used in the selective catalytic reduction (SCR) technology for nitrogen oxides control oxidizes a small fraction of sulfur dioxide in the flue gas to SO3. The extent of this oxidation depends on the catalyst formulation and SCR operating conditions. Gas-phase SO3 and sulfuric acid, on being quenched in plant equipment (e.g., air preheater and wet scrubber), result in fine acidic mist, which can cause increased plume opacity and undesirable emissions. Recently, such effects have been observed at plants firing high-S coal and equipped with SCR systems and wet scrubbers. This paper investigates the factors that affect acidic mist production in coal-fired electric utility boilers and discusses approaches for mitigating emission of this mist.

  6. Photoresist removal using gaseous sulfur trioxide cleaning technology

    NASA Astrophysics Data System (ADS)

    Del Puppo, Helene; Bocian, Paul B.; Waleh, Ahmad

    1999-06-01

    A novel cleaning method for removing photoresists and organic polymers from semiconductor wafers is described. This non-plasma method uses anhydrous sulfur trioxide gas in a two-step process, during which, the substrate is first exposed to SO3 vapor at relatively low temperatures and then is rinsed with de-ionized water. The process is radically different from conventional plasma-ashing methods in that the photoresist is not etched or removed during the exposure to SO3. Rather, the removal of the modified photoresist takes place during the subsequent DI-water rinse step. The SO3 process completely removes photoresist and polymer residues in many post-etch applications. Additional advantages of the process are absence of halogen gases and elimination of the need for other solvents and wet chemicals. The process also enjoys a very low cost of ownership and has minimal environmental impact. The SEM and SIMS surface analysis results are presented to show the effectiveness of gaseous SO3 process after polysilicon, metal an oxide etch applications. The effects of both chlorine- and fluorine-based plasma chemistries on resist removal are described.

  7. PREVENTION REFERENCE MANUAL: CHEMICAL SPECIFIC. VOL. 15: CONTROL OF ACCIDENTAL RELEASES OF SULFUR TRIOXIDE

    EPA Science Inventory

    The report, discussing sulfur trioxide (SO3), is one of a series addressing the prevention of accidental releases of toxic chemicals. SO3, a clear oily liquid or solid at typical ambient conditions, has an Immediately Dangerous to Life and Health (IDLH) concentration of 20 ppm, w...

  8. Mechanism for forming hydrogen chloride and sodium sulfate from sulfur trioxide, water, and sodium chloride

    NASA Technical Reports Server (NTRS)

    Anderson, A. B.

    1984-01-01

    A molecular orbital study of sodium sulfate and hydrogen chloride formation from sulfur trioxide, water, and sodium chloride shows no activation barrier, in agreement with recent experimental work of Kohl, Fielder, and Stearns. Two overall steps are found for the process. First, gas-phase water reacts with sulfur trioxide along a pathway involving a linear O-H-O transition state yielding closely associated hydroxyl and bisulfite which rearrange to become a hydrogen sulfate molecule. Then the hydrogen sulfate molecule transfers a hydrogen atom to a surface chloride in solid sodium chloride while an electron and a sodium cation simultaneously transfer to yield sodium bisulfate and gas-phase hydrogen chloride. This process repeats. Both of these steps represent well-known reactions for which mechanisms have not been previously determined.

  9. Studies of the fate of sulfur trioxide in coal-fired utility boilers based on modified selected condensation methods.

    PubMed

    Cao, Yan; Zhou, Hongcang; Jiang, Wu; Chen, Chien-Wei; Pan, Wei-Ping

    2010-05-01

    The formation of sulfur trioxide (SO(3)) in coal-fired utility boilers can have negative effects on boiler performance and operation, such as fouling and corrosion of equipment, efficiency loss in the air preheater (APH), increase in stack opacity, and the formation of PM(2.5). Sulfur trioxide can also compete with mercury when bonding with injected activated carbons. Tests in a lab-scale reactor confirmed there are major interferences between fly ash and SO(3) during SO(3) sampling. A modified SO(3) procedure to maximize the elimination of measurement biases, based on the inertial-filter-sampling and the selective-condensation-collecting of SO(3), was applied in SO(3) tests in three full-scale utility boilers. For the two units burning bituminous coal, SO(3) levels starting at 20 to 25 ppmv at the inlet to the selective catalytic reduction (SCR), increased slightly across the SCR, owing to catalytic conversion of SO(2) to SO(3,) and then declined in other air pollutant control device (APCD) modules downstream to approximately 5 ppmv and 15 ppmv at the two sites, respectively. In the unit burning sub-bituminous coal, the much lower initial concentration of SO(3) estimated to be approximately 1.5 ppmv at the inlet to the SCR was reduced to about 0.8 ppmv across the SCR and to about 0.3 ppmv at the exit of the wet flue gas desulfurization (WFGD). The SO(3) removal efficiency across the WFGD scrubbers at the three sites was generally 35% or less. Reductions in SO(3) across either the APH or the dry electrostatic precipitator (ESP) in units burning high-sulfur bituminous coal were attributed to operating temperatures being below the dew point of SO(3).

  10. PREPARATION OF URANIUM TRIOXIDE

    DOEpatents

    Buckingham, J.S.

    1959-09-01

    The production of uranium trioxide from aqueous solutions of uranyl nitrate is discussed. The uranium trioxide is produced by adding sulfur or a sulfur-containing compound, such as thiourea, sulfamic acid, sulfuric acid, and ammonium sulfate, to the uranyl solution in an amount of about 0.5% by weight of the uranyl nitrate hexahydrate, evaporating the solution to dryness, and calcining the dry residue. The trioxide obtained by this method furnished a dioxide with a considerably higher reactivity with hydrogen fluoride than a trioxide prepared without the sulfur additive.

  11. The Centrifugally Induced Pure Rotational Spectrum and the Structure of Sulfur Trioxide. A Microwave Fourier Transform Study of a Nonpolar Molecule

    NASA Astrophysics Data System (ADS)

    Meyer, Volker; Sutter, Dieter Hermann; Dreizler, Helmut

    1991-08-01

    The pure rotational spectrum of sulfur trioxide has been observed for the first time. A total of 25 high-J transitions could be assigned. The rotational constants, two quartic centrifugal distortion constants, and three sextic centrifugal distortion constants were determined as: B= 10 449.0667(23) MHz, C = 5216.0330(12) MHz, DJ = 9.2651 (18) kHz, DJK = -16.3922(18) kHz, HJ, = -8.8(34) • 10-3 Hz, HJK= -15.8(73) • 10-3 Hz, and HKJ = 34.2(73) • 10-3 Hz. An r0- and an re -structure are presented: r0= 1.4198(7) Å (calculated from B), r0 = 1.4210(7) Å (calculated from C), and re = 1.4175 Å

  12. Thiocyanate potentiates antimicrobial photodynamic therapy: In situ generation of the sulfur trioxide radical anion by singlet oxygen

    PubMed Central

    St Denis, Tyler G.; Vecchio, Daniela; Zadlo, Andrzej; Rineh, Ardeshir; Sadasivam, Magesh; Avci, Pinar; Huang, Liyi; Kozinska, Anna; Chandran, Rakkiyappan; Sarna, Tadeusz; Hamblin, Michael R.

    2013-01-01

    Antimicrobial photodynamic therapy (PDT) is used for the eradication of pathogenic microbial cells and involves the light excitation of dyes in the presence of O2, yielding reactive oxygen species including the hydroxyl radical (•OH) and singlet oxygen (1O2). In order to chemically enhance PDT by the formation of longer-lived radical species, we asked whether thiocyanate (SCN−) could potentiate the methylene blue (MB) and light-mediated killing of the gram-positive Staphylococcus aureus and the gram-negative Escherichia coli. SCN− enhanced PDT (10 μM MB, 5J/cm2 660 nm hv) killing in a concentration-dependent manner of S. aureus by 2.5 log10 to a maximum of 4.2 log10 at 10 mM (P < 0.001) and increased killing of E. coli by 3.6 log10 to a maximum of 5.0 log10 at 10 mM (P < 0.01). We determined that SCN− rapidly depleted O2 from an irradiated MB system, reacting exclusively with 1O2, without quenching the MB excited triplet state. SCN− reacted with 1O2, producing a sulfur trioxide radical anion (a sulfur-centered radical demonstrated by EPR spin trapping). We found that MB-PDT of SCN− in solution produced both sulfite and cyanide anions, and that addition of each of these salts separately enhanced MB-PDT killing of bacteria. We were unable to detect EPR signals of •OH, which, together with kinetic data, strongly suggests that MB, known to produce •OH and 1O2, may, under the conditions used, preferentially form 1O2. PMID:23969112

  13. Sulfonate activation of the electrophilic reactivity of chlorine and alkyl hypochlorides by the insertion of sulfur trioxide at the C1-C1 and O-C1 bonds. Addition of chlorine chloro- and ethoxysulfate to olefins

    SciTech Connect

    Zefirov, N.S.; Koz'min, A.S.; Sorokin, V.D.; Zhdankin, V.V.

    1986-10-10

    At low temperatures (-40 to -80/sup 0/C) sulfur trioxide enters the chlorine molecule (with the formation of chlorine chlorosulfate) and the ethyl hypochlorite molecule (giving chlorine ethoxysulfate). Both new compounds are highly reactive electrophilic chlorinating reagents and add to ethylene, activated alkenes (1-hexene and cyclohexene), and deactivated olefins (methyl methacrylate, tri- and tetrachloroethylene) in methylene chloride solution at low temperatures. The addition of chlorine chlorosulfate leads to the formation of ..beta..-chloroalkyl chlorosulfates with yields of 24-85%, and the addition of chlorine ethoxysulfate leads to ..beta..-chloroalkyl ethylsulfates with yields of 65-85%. The reactions with unsymmetrical olefins lead to mixtures of the regioisomers with a preference for the products from addition according to the Markovnikov rule; the addition to cyclohexene is trans-stereospecific. The investigated processes represent a new simple approach to the production of sulfate-activated chlorinating reagents and extend the possibilities for functional substitution of olefins.

  14. Pyrolysis of high sulfur Indian coals

    SciTech Connect

    B.P. Baruah; Puja Khare

    2007-12-15

    Pyrolysis experiments under laboratory conditions for five numbers of high sulfur coal samples from the states of Meghalaya and Nagaland, India, were carried out at temperatures of 450, 600, 850, and 1000{sup o}C, respectively. The yield of products and thermal release of sulfur from these coals are investigated. The distribution of sulfur in the pyrolyzed products, i.e., char/coke, gas, and tar, is also reported. Hydrocarbon and sulfurous gases released at different temperatures were analyzed by a gas chromatograph (GC) with an FID (flame ionized detector) and an FPD (flame photometric detector), respectively. H{sub 2}S evolution during coal pyrolysis was found to be a function of temperature up to 850{sup o}C. The low concentration of SO{sub 2} detected for some of the samples is due to decomposition of inorganic sulphates present. Evolution of methane for the coals tested increases with the increase of temperature. Maximum sulfur release was found in the range of 600-850{sup o}C and has a decreasing tendency from 850-1000{sup o}C, which might be due to the incorporation of sulfur released into the coal matrix. Activation energies for sulfur release were found in the range of 38-228 kJ mol{sup -1}, which were higher than the reported activation energies for lignites and bituminous coals mainly due to highly stable organic sulfur functionalities. 52 refs., 9 figs., 6 tabs.

  15. Antimony trioxide

    Integrated Risk Information System (IRIS)

    Antimony trioxide ; CASRN 1309 - 64 - 4 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogeni

  16. Graphene-wrapped sulfur nanospheres with ultra-high sulfur loading for high energy density lithium-sulfur batteries

    NASA Astrophysics Data System (ADS)

    Liu, Ya; Guo, Jinxin; Zhang, Jun; Su, Qingmei; Du, Gaohui

    2015-01-01

    Lithium-sulfur (Li-S) battery with high theoretical energy density is one of the most promising energy storage systems for electric vehicles and intermittent renewable energy. However, due to the poor conductivity of the active material, considerable weight of the electrode is occupied by the conductive additives. Here we report a graphene-wrapped sulfur nanospheres composite (S-nanosphere@G) with sulfur content up to 91 wt% as the high energy density cathode material for Li-S battery. The sulfur nanospheres with diameter of 400-500 nm are synthesized through a solution-based approach with the existence of polyvinylpyrrolidone (PVP). Then the sulfur nanospheres are uniformly wrapped by conductive graphene sheets through the electrostatic interaction between graphene oxide and PVP, followed by reducing of graphene oxide with hydrazine. The design of graphene wrapped sulfur nanoarchitecture provides flexible conductive graphene coating with void space to accommodate the volume expansion of sulfur and to minimize polysulfide dissolution. As a result, the S-nanosphere@G nanocomposite with 91 wt% sulfur shows a reversible initial capacity of 970 mA h g-1 and an average columbic efficiency > 96% over 100 cycles at a rate of 0.2 C. Taking the total mass of electrode into account, the S-nanosphere@G composite is a promising cathode material for high energy density Li-S batteries.

  17. Rapid sulfur capture studies at high temperatures

    SciTech Connect

    Richards, G.A.; Lawson, W.F.; Maloney, D.J.; Shaw, D.W.

    1990-12-01

    Determine conditions that would reproduce optimum sulfur capture ( super-equilibrium'') behavior. No attempt was made to extract kinetic data for calcination or sulfur capture, as might be done in a comprehensive study of sorbent behavior. While some interesting anomalies are present in the calcination data and in the limited surface area data, no attempt was made to pursue those issues. Since little sulfur capture was observed at operating conditions where super-equilibrium'' might be expected to occur, tests were stopped when the wide range of parameters that were studied failed to produce significant sulfur capture via the super-equilibrium mechanism. Considerable space in this report is devoted to a description of the experiment, including details of the GTRC construction. This description is included because we have received requests for a detailed description of the GTRC itself, as well as the pressurized dry powder feed system. In addition, many questions about accurately sampling the sulfur species from a high-temperature, high-pressure reactor were raised during the course of this investigation. A full account of the development of the gas and particulate sampling train in thus provided. 8 refs., 17 figs., 2 tabs.

  18. Method for removing sulfur oxide from waste gases and recovering elemental sulfur

    DOEpatents

    Moore, Raymond H.

    1977-01-01

    A continuous catalytic fused salt extraction process is described for removing sulfur oxides from gaseous streams. The gaseous stream is contacted with a molten potassium sulfate salt mixture having a dissolved catalyst to oxidize sulfur dioxide to sulfur trioxide and molten potassium normal sulfate to solvate the sulfur trioxide to remove the sulfur trioxide from the gaseous stream. A portion of the sulfur trioxide loaded salt mixture is then dissociated to produce sulfur trioxide gas and thereby regenerate potassium normal sulfate. The evolved sulfur trioxide is reacted with hydrogen sulfide as in a Claus reactor to produce elemental sulfur. The process may be advantageously used to clean waste stack gas from industrial plants, such as copper smelters, where a supply of hydrogen sulfide is readily available.

  19. Facile synthesis of single crystalline rhenium (VI) trioxide nanocubes with high catalytic efficiency for photodegradation of methyl orange.

    PubMed

    Chong, Yuan Yi; Fan, Wai Yip

    2013-05-01

    Single-crystalline rhenium trioxide (ReO3) nanocubes have been prepared for the first time without the need of surfactants via controlled reduction of rhenium (VII) oxide (Re2O7), sandwiched between silicon wafers at 250°C. The metallic ReO3 nanocubes are magnetic and possess surface plasmon resonance (SPR) bands down to the NIR region. The nanocubes also show very high catalytic activity toward the photodegradation of methyl orange (MO) under ambient conditions. A mechanism has been proposed to account for the photodegradation process.

  20. A New Use for High-Sulfur Coal

    NASA Technical Reports Server (NTRS)

    Lawson, D. D.; England, C.

    1982-01-01

    New process recovers some of economic value of high-sulfur coal. Although high-sulfur content is undesirable in most coal-utilization schemes (such as simple burning), proposed process prefers high-sulfur coal to produce electrical power or hydrogen. Potential exists for widespread application in energy industry.

  1. Arsenic Trioxide Injection

    MedlinePlus

    Arsenic trioxide is used to treat acute promyelocytic leukemia (APL; a type of cancer in which there ... worsened following treatment with other types of chemotherapy. Arsenic trioxide is in a class of medications called ...

  2. Sulfur nanocrystals anchored graphene composite with highly improved electrochemical performance for lithium-sulfur batteries

    NASA Astrophysics Data System (ADS)

    Zhang, Jun; Dong, Zimin; Wang, Xiuli; Zhao, Xuyang; Tu, Jiangping; Su, Qingmei; Du, Gaohui

    2014-12-01

    Two kinds of graphene-sulfur composites with 50 wt% of sulfur are prepared using hydrothermal method and thermal mixing, respectively. Transmission Electron Microscopy (TEM) and Energy Dispersive X-ray Spectra mapping show that sulfur nanocrystals with size of ∼5 nm dispersed on graphene sheets homogeneously for the sample prepared by hydrothermal method (NanoS@G). While for the thermal mixed graphene-sulfur composite (S-G mixture), sulfur shows larger and uneven size (50-200 nm). X-ray Photoelectron Spectra (XPS) reveals the strong chemical bonding between the sulfur nanocrystals and graphene. Comparing with the S-G mixture, the NanoS@G composite shows highly improved electrochemical performance as cathode for lithium-sulfur (Li-S) battery. The NanoS@G composite delivers an initial capacity of 1400 mAh g-1 with the sulfur utilization of 83.7% at a current density of 335 mA g-1. The capacity keeps above 720 mAh g-1 over 100 cycles. The strong adherence of the sulfur nanocrystals on graphene immobilizes sulfur and polysulfides species and suppressed the "shuttle effect", resulting higher coulombic efficiency and better capacity retention. Electrochemical impedance also suggests that the strong bonding enabled rapid electronic/ionic transport and improved electrochemical kinetics, therefore good rate capability is obtained. These results demonstrate that the NanoS@G composite is a very promising candidate for high-performance Li-S batteries.

  3. A mesoporous carbon–sulfur composite as cathode material for high rate lithium sulfur batteries

    SciTech Connect

    Choi, Hyunji; Zhao, Xiaohui; Kim, Dul-Sun; Ahn, Hyo-Jun; Kim, Ki-Won; Cho, Kwon-Koo; Ahn, Jou-Hyeon

    2014-10-15

    Highlights: • CMK-3 mesoporous carbon was synthesized as conducting reservoir for housing sulfur. • Sulfur/CMK-3 composites were prepared by two-stage thermal treatment. • The composite at 300 °C for 20 h shows improved electrochemical properties. - Abstract: Sulfur composite was prepared by encapsulating sulfur into CMK-3 mesoporous carbon with different heating times and then used as the cathode material for lithium sulfur batteries. Thermal treatment at 300 °C plays an important role in the sulfur encapsulation process. With 20 h of heating time, a portion of sulfur remained on the surface of carbon, whereas with 60 h of heating time, sulfur is confined deeply in the small pores of carbon that cannot be fully exploited in the redox reaction, thus causing low capacity. The S/CMK-3 composite with thermal treatment for 40 h at 300 °C contained 51.3 wt.% sulfur and delivered a high initial capacity of 1375 mA h g{sup −1} at 0.1 C. Moreover, it showed good capacity retention of 704 mA h g{sup −1} at 0.1 C and 578 mA h g{sup −1} at 2 C even after 100 cycles, which proves its potential as a cathode material for high capability lithium sulfur batteries.

  4. Fibrous hybrid of graphene and sulfur nanocrystals for high-performance lithium-sulfur batteries.

    PubMed

    Zhou, Guangmin; Yin, Li-Chang; Wang, Da-Wei; Li, Lu; Pei, Songfeng; Gentle, Ian Ross; Li, Feng; Cheng, Hui-Ming

    2013-06-25

    Graphene-sulfur (G-S) hybrid materials with sulfur nanocrystals anchored on interconnected fibrous graphene are obtained by a facile one-pot strategy using a sulfur/carbon disulfide/alcohol mixed solution. The reduction of graphene oxide and the formation/binding of sulfur nanocrystals were integrated. The G-S hybrids exhibit a highly porous network structure constructed by fibrous graphene, many electrically conducting pathways, and easily tunable sulfur content, which can be cut and pressed into pellets to be directly used as lithium-sulfur battery cathodes without using a metal current-collector, binder, and conductive additive. The porous network and sulfur nanocrystals enable rapid ion transport and short Li(+) diffusion distance, the interconnected fibrous graphene provides highly conductive electron transport pathways, and the oxygen-containing (mainly hydroxyl/epoxide) groups show strong binding with polysulfides, preventing their dissolution into the electrolyte based on first-principles calculations. As a result, the G-S hybrids show a high capacity, an excellent high-rate performance, and a long life over 100 cycles. These results demonstrate the great potential of this unique hybrid structure as cathodes for high-performance lithium-sulfur batteries.

  5. Infiltrating sulfur into a highly porous carbon sphere as cathode material for lithium–sulfur batteries

    SciTech Connect

    Zhao, Xiaohui; Kim, Dul-Sun; Ahn, Hyo-Jun; Kim, Ki-Won; Cho, Kwon-Koo; Ahn, Jou-Hyeon

    2014-10-15

    Highlights: • A highly porous carbon (HPC) with regular spherical morphology was synthesized. • Sulfur/HPC composites were prepared by melt–diffusion method. • Sulfur/HPC composites showed improved cyclablity and long-term cycle life. - Abstract: Sulfur composite material with a highly porous carbon sphere as the conducting container was prepared. The highly porous carbon sphere was easily synthesized with resorcinol–formaldehyde precursor as the carbon source. The morphology of the carbon was observed with field emission scanning electron microscope and transmission electron microscope, which showed a well-defined spherical shape. Brunauer–Emmett–Teller analysis indicated that it possesses a high specific surface area of 1563 m{sup 2} g{sup −1} and a total pore volume of 2.66 cm{sup 3} g{sup −1} with a bimodal pore size distribution, which allow high sulfur loading and easy transportation of lithium ions. Sulfur carbon composites with varied sulfur contents were prepared by melt–diffusion method and lithium sulfur cells with the sulfur composites showed improved cyclablity and long-term cycle life.

  6. Sulfur

    USGS Publications Warehouse

    Apodaca, L.E.

    2012-01-01

    In 2011, elemental sulfur and the byproduct sulfuric acid were produced at 109 operations in 29 states and the U.S. Virgin Islands. Total shipments were valued at about $1.6 billion. Elemental sulfur production was 8.2 Mt (9 million st); Louisiana and Texas accounted for about 53 percent of domestic production.

  7. Reinforced Conductive Confinement of Sulfur for Robust and High-Performance Lithium-Sulfur Batteries.

    PubMed

    Lai, Chao; Wu, Zhenzhen; Gu, Xingxing; Wang, Chao; Xi, Kai; Kumar, R Vasant; Zhang, Shanqing

    2015-11-04

    Sulfur is an attractive cathode material in energy storage devices due to its high theoretical capacity of 1672 mAh g(-1). However, practical application of lithium-sulfur (Li-S) batteries can be achieved only when the major barriers, including the shuttling effect of polysulfides (Li2Sx, x = 3-8), significant volume change (∼80%), and the resultant rapid deterioration of electrodes, are tackled. Here, we propose an "inside-out" synthesis strategy by mimicking the structure of the pomegranate fruit to achieve conductive confinement of sulfur to address these issues. In the proposed pomegranate-like structure, sulfur and carbon nanotubes composite is encapsulated by the in situ formed amorphous carbon network, which allows the regeneration of electroactive material sulfur and the confinement of the sulfur as well as the lithium polysulfide within the electrical conductive carbon network. Consequently, a highly robust sulfur cathode is obtained, delivering remarkable performance in a Li-S battery. The obtained composite cathode shows a reversible capacity of 691 mAh g(-1) after 200 cycles with impressive cycle stability at the current density of 1600 mA g(-1).

  8. Three-dimensional porous carbon composites containing high sulfur nanoparticle content for high-performance lithium–sulfur batteries

    PubMed Central

    Li, Guoxing; Sun, Jinhua; Hou, Wenpeng; Jiang, Shidong; Huang, Yong; Geng, Jianxin

    2016-01-01

    Sulfur is a promising cathode material for lithium–sulfur batteries because of its high theoretical capacity (1,675 mA h g−1); however, its low electrical conductivity and the instability of sulfur-based electrodes limit its practical application. Here we report a facile in situ method for preparing three-dimensional porous graphitic carbon composites containing sulfur nanoparticles (3D S@PGC). With this strategy, the sulfur content of the composites can be tuned to a high level (up to 90 wt%). Because of the high sulfur content, the nanoscale distribution of the sulfur particles, and the covalent bonding between the sulfur and the PGC, the developed 3D S@PGC cathodes exhibit excellent performance, with a high sulfur utilization, high specific capacity (1,382, 1,242 and 1,115 mA h g−1 at 0.5, 1 and 2 C, respectively), long cycling life (small capacity decay of 0.039% per cycle over 1,000 cycles at 2 C) and excellent rate capability at a high charge/discharge current. PMID:26830732

  9. Atomic-Layer-Deposition Functionalized Carbonized Mesoporous Wood Fiber for High Sulfur Loading Lithium Sulfur Batteries.

    PubMed

    Luo, Chao; Zhu, Hongli; Luo, Wei; Shen, Fei; Fan, Xiulin; Dai, Jiaqi; Liang, Yujia; Wang, Chunsheng; Hu, Liangbing

    2017-04-14

    Lithium-sulfur battery (LSB) as one of the most promising energy storage devices suffers from poor conductivity of sulfur and fast capacity decay triggered by the dissolution of polysulfides. In this work, functionalized carbonized mesoporous wood fiber (f-CMWF) is employed as a host to accommodate sulfur for the first time. Natural wood microfiber has unique hierarchical and mesoporous structure, which is well maintained after carbonization. With such a hierarchical mesoporous structure, a high sulfur loading of 76 wt% is achieved in CMWF electrodes. The pore size of CMWF is tunable by atomic layer deposition (ALD) of 5 nm Al2O3 coating to form the f-CMWF. Such a thin layer coating slightly decreases the sulfur loading to 70%, but remarkably promotes the cyclic stability of sulfur cathode, which delivers an initial capacity of 1115 mAh g-1, and maintains a reversible capacity of 859 mAh g-1 for 450 cycles, corresponding to a slow capacity decay rate of 0.046% per cycle. More importantly, natural wood microfiber is firstly used as a raw material for sulfur encapsulating. This work is also critical for using low cost and mesoporous biomass carbon as bi-functional scaffold for LSB.

  10. Sulfur removal from high-sulfur Illinois coal by low-temperature perchloroethylene (PCE) extraction

    SciTech Connect

    Chou, M.I.M.

    1991-01-01

    A pre-combustion coal desulfurization process at 120{degree}C using perchloroethylene (PCE) to remove up to 70% of the organic sulfur has been developed by the Midwest Ore Processing Co. (MWOPC). However, this process has not yet proven to be as successful with Illinois coals as it has for Ohio and Indiana coals. The organic sulfur removal has been achieved only with highly oxidized Illinois coals containing high sulfatic sulfur. A logical explanation for this observation is vital to successful process optimization for the use of Illinois coals. In addition, the high levels of organic sulfur removals observed by the MWOPC may be due to certain errors involved in the ASTM data interpretation; this needs verification. For example, elemental sulfur extracted by the PCE may be derived from pyrite oxidation during coal pre-oxidation, but it may be interpreted as organic sulfur removed by the PCE using ASTM analysis. The goals of this research are: (1) to independently confirm and possibly to improve the organic sulfur removal from Illinois coals with the PCE desulfurization process reported by the MWOPC, (2) to verify the forms-of-sulfur determination using the ASTM method for the PCE process evaluation, and (3) to determine the suitability of Illinois coals for use in the PCE desulfurization process. This project involves the Illinois State Geological Survey (ISGS), Eastern Illinois University (EIU), the University of Illinois-Urbana/Champaign (UI-UC), and the University of Kentucky, Lexington (UK). This is the first year of a two-year project.

  11. A complementary electrochromic device with highly improved performance based on brick-like hydrated tungsten trioxide film.

    PubMed

    Jiao, Zhihui; Wang, Jinmin; Ke, Lin; Sun, Xiao Wei; Demir, Hilmi Volkan

    2012-05-01

    Uniform and well adhesive nanostructured hydrated tungsten trioxide (3WO3 x H2O) films were grown on fluorine doped tin oxide (FTO) substrate via a facile and template-free crystal-seed-assisted hydrothermal method by addition of ammonium sulfate ((NH4)2SO4) and hydrogen peroxide (H2O2). X-ray diffraction (XRD) studies indicated that the films are of orthorhombic structure. Scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM) analysis showed that the film was composed of brick-like nanostructures with a preferred growing direction along (002). The influence of seed layer, (NH4)2SO4 and H2O2 on the products were also studied. The film showed good cyclic stability, comparable switching speed and coloration efficiency (30.1 cm2 C(-1)). A complementary electrochromic device based on the film and Prussian blue depicted highly improved color contrast, coloration/bleaching response (1.8 and 3.7 s respectively) and coloration efficiency (164.6 cm2 C(-1)).

  12. Microbial degradation of high impact polystyrene (HIPS), an e-plastic with decabromodiphenyl oxide and antimony trioxide.

    PubMed

    Sekhar, Vini C; Nampoothiri, K Madhavan; Mohan, Arya J; Nair, Nimisha R; Bhaskar, Thallada; Pandey, Ashok

    2016-11-15

    Accumulation of electronic waste has increased catastrophically and out of that various plastic resins constitute one of the leading thrown out materials in the electronic machinery. Enrichment medium, containing high impact polystyrene (HIPS) with decabromodiphenyl oxide and antimony trioxide as sole carbon source, was used to isolate microbial cultures. The viability of these cultures in the e-plastic containing mineral medium was further confirmed by triphenyl tetrazolium chloride (TTC) reduction test. Four cultures were identified by 16S rRNA sequencing as Enterobacter sp., Citrobacter sedlakii, Alcaligenes sp. and Brevundimonas diminuta. Biodegradation experiments were carried out in flask level and gelatin supplementation (0.1% w/v) along with HIPS had increased the degradation rate to a maximum of 12.4% (w/w) within 30days. This is the first report for this kind of material. The comparison of FTIR, NMR, and TGA analysis of original and degraded e-plastic films revealed structural changes under microbial treatment. Polystyrene degradation intermediates in the culture supernatant were also detected using HPLC analysis. The gravity of biodegradation was validated by morphological changes under scanning electron microscope. All isolates displayed depolymerase activity to substantiate enzymatic degradation of e-plastic.

  13. Sulfur/three-dimensional graphene composite for high performance lithium-sulfur batteries

    NASA Astrophysics Data System (ADS)

    Xu, Chunmei; Wu, Yishan; Zhao, Xuyang; Wang, Xiuli; Du, Gaohui; Zhang, Jun; Tu, Jiangping

    2015-02-01

    A sulfur/graphene composite is prepared by loading elemental sulfur into three-dimensional graphene (3D graphene), which is assembled using a metal ions assisted hydrothermal method. When used as cathode materials for lithium-sulfur (Li-S) batteries, the sulfur/graphene composite (S@3D-graphene) with 73 wt % sulfur shows a significantly enhanced cycling performance (>700 mAh g-1 after 100 cycles at 0.1C rate with a Coulombic efficiency > 96%) as well as high rate capability with a capacity up to 500 mAh g-1 at 2C rate (3.35 A g-1). The superior electrochemical performance could be attributed to the highly porous structure of three-dimensional graphene that not only enables stable and continue pathway for rapid electron and ion transportation, but also restrain soluble polysulfides and suppress the "shuttle effect". Moreover, the robust structure of 3D graphene can keep cathode integrity and accommodate the volume change during high-rate charge/discharge processes, making it a promising candidate as cathode for high performance Li-S batteries.

  14. Biomimetic Ant-Nest Electrode Structures for High Sulfur Ratio Lithium-Sulfur Batteries.

    PubMed

    Ai, Guo; Dai, Yiling; Mao, Wenfeng; Zhao, Hui; Fu, Yanbao; Song, Xiangyun; En, Yunfei; Battaglia, Vincent S; Srinivasan, Venkat; Liu, Gao

    2016-09-14

    The lithium-sulfur (Li-S) rechargeable battery has the benefit of high gravimetric energy density and low cost. Significant research currently focuses on increasing the sulfur loading and sulfur/inactive-materials ratio, to improve life and capacity. Inspired by nature's ant-nest structure, this research results in a novel Li-S electrode that is designed to meet both goals. With only three simple manufacturing-friendly steps, which include slurry ball-milling, doctor-blade-based laminate casting, and the use of the sacrificial method with water to dissolve away table salt, the ant-nest design has been successfully recreated in an Li-S electrode. The efficient capabilities of the ant-nest structure are adopted to facilitate fast ion transportation, sustain polysulfide dissolution, and assist efficient precipitation. High cycling stability in the Li-S batteries, for practical applications, has been achieved with up to 3 mg·cm(-2) sulfur loading. Li-S electrodes with up to a 85% sulfur ratio have also been achieved for the efficient design of this novel ant-nest structure.

  15. Method of removing and recovering elemental sulfur from highly reducing gas streams containing sulfur gases

    DOEpatents

    Gangwal, Santosh K.; Nikolopoulos, Apostolos A.; Dorchak, Thomas P.; Dorchak, Mary Anne

    2005-11-08

    A method is provided for removal of sulfur gases and recovery of elemental sulfur from sulfur gas containing supply streams, such as syngas or coal gas, by contacting the supply stream with a catalyst, that is either an activated carbon or an oxide based catalyst, and an oxidant, such as sulfur dioxide, in a reaction medium such as molten sulfur, to convert the sulfur gases in the supply stream to elemental sulfur, and recovering the elemental sulfur by separation from the reaction medium.

  16. A Cooperative Interface for Highly Efficient Lithium-Sulfur Batteries.

    PubMed

    Peng, Hong-Jie; Zhang, Ze-Wen; Huang, Jia-Qi; Zhang, Ge; Xie, Jin; Xu, Wen-Tao; Shi, Jia-Le; Chen, Xiang; Cheng, Xin-Bing; Zhang, Qiang

    2016-11-01

    A cooperative interface constructed by "lithiophilic" nitrogen-doped graphene frameworks and "sulfiphilic" nickel-iron layered double hydroxides (LDH@NG) is proposed to synergistically afford bifunctional Li and S binding to polysulfides, suppression of polysulfide shuttles, and electrocatalytic activity toward formation of lithium sulfides for high-performance lithium-sulfur batteries. LDH@NG enables high rate capability, long lifespan, and efficient stabilization of both sulfur and lithium electrodes.

  17. Graphene-Wrapped Sulfur Particles as a Rechargeable Lithium-Sulfur Battery Cathode Material with High Capacity and Cycling Stability

    NASA Astrophysics Data System (ADS)

    Wang, Hailiang; Yang, Yuan; Liang, Yongye; Robinson, Joshua Tucker; Li, Yanguang; Jackson, Ariel; Cui, Yi; Dai, Hongjie

    2011-07-01

    We report the synthesis of a graphene-sulfur composite material by wrapping polyethyleneglycol (PEG) coated submicron sulfur particles with mildly oxidized graphene oxide sheets decorated by carbon black nanoparticles. The PEG and graphene coating layers are important to accommodating volume expansion of the coated sulfur particles during discharge, trapping soluble polysulfide intermediates and rendering the sulfur particles electrically conducting. The resulting graphene-sulfur composite showed high and stable specific capacities up to ~600mAh/g over more than 100 cycles, representing a promising cathode material for rechargeable lithium batteries with high energy density.

  18. Graphene-wrapped sulfur particles as a rechargeable lithium-sulfur battery cathode material with high capacity and cycling stability.

    PubMed

    Wang, Hailiang; Yang, Yuan; Liang, Yongye; Robinson, Joshua Tucker; Li, Yanguang; Jackson, Ariel; Cui, Yi; Dai, Hongjie

    2011-07-13

    We report the synthesis of a graphene-sulfur composite material by wrapping poly(ethylene glycol) (PEG) coated submicrometer sulfur particles with mildly oxidized graphene oxide sheets decorated by carbon black nanoparticles. The PEG and graphene coating layers are important to accommodating volume expansion of the coated sulfur particles during discharge, trapping soluble polysulfide intermediates, and rendering the sulfur particles electrically conducting. The resulting graphene-sulfur composite showed high and stable specific capacities up to ∼600 mAh/g over more than 100 cycles, representing a promising cathode material for rechargeable lithium batteries with high energy density.

  19. High Energy Density Lithium-Sulfur Batteries: Challenges of Thick Sulfur Cathodes

    SciTech Connect

    Lu, Dongping; Zheng, Jianming; Li, Qiuyan; Xie, Xi; Ferrara, Seth A.; Nie, Zimin; Mehdi, Beata L.; Browning, Nigel D.; Zhang, Jiguang; Graff, Gordon L.; Liu, Jun; Xiao, Jie

    2015-08-19

    High energy and cost-effective lithium sulfur (Li-S) battery technology has been vigorously revisited in recent years due to the urgent need of advanced energy storage technologies for transportation and large-scale energy storage applications. However, the market penetration of Li-S batteries has been plagued due to the gap in scientific knowledge between the fundamental research and the real application need. Herein, we focus on the cathode part of the Li-S system and discuss 1) the progress and issues of literature-reported sulfur cathode; 2) how to employ materials chemistry/science to address the challenges to thicken sulfur cathode; 3) the factors that affect the electrochemical performances of Li-S cells constructed at a relevant scale. This progress report attempts to tie the fundamental understanding closely to the practical application of Li-S batteries so that it may provide new insights for the research efforts of Li-S battery technology.

  20. Superior electrochemical performance of sulfur/graphene nanocomposite material for high-capacity lithium-sulfur batteries.

    PubMed

    Wang, Bei; Li, Kefei; Su, Dawei; Ahn, Hyojun; Wang, Guoxiu

    2012-06-01

    Sulfur/graphene nanocomposite material has been prepared by incorporating sulfur into the graphene frameworks through a melting process. Field-emission scanning electron microscope analysis shows a homogeneous distribution of sulfur in the graphene nanosheet matrix. The sulfur/graphene nanocomposite exhibits a super-high lithium-storage capacity of 1580 mA h g(-1) and a satisfactory cycling performance in lithium-sulfur cells. The enhancement of the reversible capacity and cycle life could be attributed to the flexible graphene nanosheet matrix, which acts as a conducting medium and a physical buffer to cushion the volume change of sulfur during the lithiation and delithiation process. Graphene-based nanocomposites can significantly improve the electrochemical performance of lithium-sulfur batteries.

  1. Coaxial Three-Layered Carbon/Sulfur/Polymer Nanofibers with High Sulfur Content and High Utilization for Lithium-Sulfur Batteries.

    PubMed

    He, Feng; Ye, Jian; Cao, Yuliang; Xiao, Lifen; Yang, Hanxi; Ai, Xinping

    2017-03-27

    Great progress has been made on the cyclability and material utilization in recent development of lithium-sulfur (Li-S) batteries; however, most of the sulfur electrodes reported so far have a considerable low loading of sulfur (60%), which causes a substantial decrease in energy density and is therefore difficult for application in batteries. To deal with this issue, we fabricate a novel sulfur composite with a coaxial three-layered structure, in which sulfur is deposited on carbon fibers and coated with poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT/PSS), thus enabling a high sulfur loading of 70.8 wt % without the expense of its electrochemical performance. Benefiting from the rigid conductive framework of carbon fibers and flexible buffering matrix of the polymer for blocking the diffusion loss of discharge intermediates, the as-fabricated composite electrode exhibits a high initial reversible capacity of 1272 mA h g(-1) (based on the total mass of the composite), a stable cyclability with a retained capacity of 807 mA h g(-1) after 200 cycles, and a high Coulombic efficiency of ∼99% upon extended cycling, offering a new selection for practical application in Li-S batteries.

  2. Advanced Sulfur Cathode Enabled by Highly Crumpled Nitrogen-Doped Graphene Sheets for High-Energy-Density Lithium-Sulfur Batteries.

    PubMed

    Song, Jiangxuan; Yu, Zhaoxin; Gordin, Mikhail L; Wang, Donghai

    2016-02-10

    Herein, we report a synthesis of highly crumpled nitrogen-doped graphene sheets with ultrahigh pore volume (5.4 cm(3)/g) via a simple thermally induced expansion strategy in absence of any templates. The wrinkled graphene sheets are interwoven rather than stacked, enabling rich nitrogen-containing active sites. Benefiting from the unique pore structure and nitrogen-doping induced strong polysulfide adsorption ability, lithium-sulfur battery cells using these wrinkled graphene sheets as both sulfur host and interlayer achieved a high capacity of ∼1000 mAh/g and exceptional cycling stability even at high sulfur content (≥80 wt %) and sulfur loading (5 mg sulfur/cm(2)). The high specific capacity together with the high sulfur loading push the areal capacity of sulfur cathodes to ∼5 mAh/cm(2), which is outstanding compared to other recently developed sulfur cathodes and ideal for practical applications.

  3. Coaxial-cable structure composite cathode material with high sulfur loading for high performance lithium-sulfur batteries

    NASA Astrophysics Data System (ADS)

    Li, Qiang; Zhang, Zhian; Guo, Zaiping; Zhang, Kai; Lai, Yanqing; Li, Jie

    2015-01-01

    Hollow carbon nanofiber@nitrogen-doped porous carbon (HCNF@NPC) coaxial-cable structure composite, which is carbonized from HCNF@polydopamine, is prepared as an improved high conductive carbon matrix for encapsulating sulfur as a composite cathode material for lithium-sulfur batteries. The prepared HCNF@NPC-S composite with high sulfur content of approximately 80 wt% shows an obvious coaxial-cable structure with an NPC layer coating on the surface of the linear HCNFs along the length and sulfur homogeneously distributes in the coating layer. This material exhibits much better electrochemical performance than the HCNF-S composite, delivers initial discharge capacity of 982 mAh g-1 and maintains a high capacity retention rate of 63% after 200 cycles at a high current density of 837.5 mA g-1. The significantly enhanced electrochemical performance of the HCNF@NPC-S composite is attributed to the unique coaxial-cable structure, in which the linear HCNF core provides electronic conduction pathways and works as mechanical support, and the NPC shell with nitrogen-doped and porous structure can trap sulfur/polysulfides and provide Li+ conductive pathways.

  4. A dual coaxial nanocable sulfur composite for high-rate lithium-sulfur batteries

    NASA Astrophysics Data System (ADS)

    Li, Zhen; Yuan, Lixia; Yi, Ziqi; Liu, Yang; Xin, Ying; Zhang, Zhaoliang; Huang, Yunhui

    2014-01-01

    Lithium-sulfur batteries have great potential for some high energy applications such as in electric vehicles and smart grids due to their high capacity, natural abundance, low cost and environmental friendliness. But they suffer from rapid capacity decay and poor rate capability. The problems are mainly related to the dissolution of the intermediate polysulfides in the electrolyte, and to the poor conductivity of sulfur and the discharge products. In this work, we propose a novel dual coaxial nanocable sulfur composite fabricated with multi-walled nanotubes (MWCNT), nitrogen-doped porous carbon (NPC) and polyethylene glycol (PEG), i.e. MWCNTs@S/NPC@PEG nanocable, as a cathode material for Li-S batteries. In such a coaxial structure, the middle N-doped carbon with hierarchical porous structure provides a nanosized capsule to contain and hold the sulfur particles; the inner MWCNTs and the outer PEG layer can further ensure the fast electronic transport and prevent the dissolution of the polysulfides into the electrolyte, respectively. The as-designed MWCNT@S/NPC@PEG composite shows good cycling stability and excellent rate capability. The capacity is retained at 527 mA h g-1 at 1 C after 100 cycles, and 791 mA h g-1 at 0.5 C and 551 mA h g-1 at 2 C after 50 cycles. Especially, the high-rate capability is outstanding with 400 mA h g-1 at 5 C.Lithium-sulfur batteries have great potential for some high energy applications such as in electric vehicles and smart grids due to their high capacity, natural abundance, low cost and environmental friendliness. But they suffer from rapid capacity decay and poor rate capability. The problems are mainly related to the dissolution of the intermediate polysulfides in the electrolyte, and to the poor conductivity of sulfur and the discharge products. In this work, we propose a novel dual coaxial nanocable sulfur composite fabricated with multi-walled nanotubes (MWCNT), nitrogen-doped porous carbon (NPC) and polyethylene glycol (PEG

  5. Graphene/Sulfur/Carbon Nanocomposite for High Performance Lithium-Sulfur Batteries

    PubMed Central

    Jin, Kangke; Zhou, Xufeng; Liu, Zhaoping

    2015-01-01

    Here, we report a two-step synthesis of graphene/sulfur/carbon ternary composite with a multilayer structure. In this composite, ultrathin S layers are uniformly deposited on graphene nanosheets and covered by a thin layer of amorphous carbon derived from β-cyclodextrin on the surface. Such a unique microstructure, not only improves the electrical conductivity of sulfur, but also effectively inhibits the dissolution of polysulfides during charging/discharging processes. As a result, this ternary nanocomposite exhibits excellent electrochemical performance. It can deliver a high initial discharge and charge capacity of 1410 mAh·g−1 and 1370 mAh·g−1, respectively, and a capacity retention of 63.8% can be achieved after 100 cycles at 0.1 C (1 C = 1675 mA·g−1). A relatively high specific capacity of 450 mAh·g−1 can still be retained after 200 cycles at a high rate of 2 C. The synthesis process introduced here is simple and broadly applicable to the modification of sulfur cathode for better electrochemical performance. PMID:28347077

  6. High pressure sulfuric acid decomposition experiments for the sulfur-iodine thermochemical cycle.

    SciTech Connect

    Velasquez, Carlos E; Reay, Andrew R.; Andazola, James C.; Naranjo, Gerald E.; Gelbard, Fred

    2005-09-01

    A series of three pressurized sulfuric acid decomposition tests were performed to (1) obtain data on the fraction of sulfuric acid catalytically converted to sulfur dioxide, oxygen, and water as a function of temperature and pressure, (2) demonstrate real-time measurements of acid conversion for use as process control, (3) obtain multiple measurements of conversion as a function of temperature within a single experiment, and (4) assess rapid quenching to minimize corrosion of metallic components by undecomposed acid. All four of these objectives were successfully accomplished. This report documents the completion of the NHI milestone on high pressure H{sub 2}SO{sub 4} decomposition tests for the Sulfur-Iodine (SI) thermochemical cycle project. All heated sections of the apparatus, (i.e. the boiler, decomposer, and condenser) were fabricated from Hastelloy C276. A ceramic acid injection tube and a ceramic-sheathed thermocouple were used to minimize corrosion of hot liquid acid on the boiler surfaces. Negligible fracturing of the platinum on zirconia catalyst was observed in the high temperature decomposer. Temperature measurements at the exit of the decomposer and at the entry of the condenser indicated that the hot acid vapors were rapidly quenched from about 400 C to less than 20 C within a 14 cm length of the flow path. Real-time gas flow rate measurements of the decomposition products provided a direct measurement of acid conversion. Pressure in the apparatus was preset by a pressure-relief valve that worked well at controlling the system pressure. However, these valves sometimes underwent abrupt transitions that resulted in rapidly varying gas flow rates with concomitant variations in the acid conversion fraction.

  7. Sulfur-oxygen processes on Io

    NASA Technical Reports Server (NTRS)

    Nelson, Robert M.; Smythe, William D.

    1987-01-01

    Laboratory studies of irradiated sulfur dioxide frost have found that sulfur trioxide should be formed as a consequence of the irradiation process. The spectral reflectance of solid sulfur trioxide was measured in the laboratory and it was found that the compound has strong absorption features at 3.37 and 3.70 microns. These features are not present in the spectral geometric albedo of Io. This is interpreted as an indication that sulfur trioxide may exist in such limited abundance that it is undetectable in disk averaged spectrophotometry. It is suggested that the Near-Infrared Mapping Spectrometer on the Galileo spacecraft should be able to identify condensed sulfur trioxide on Io particularly in regions bordering the sulfur dioxide deposits. The presence of elemental sulfur on Io's surface has been questioned on several grounds, most notably the suggested production process (quenched molten sulfur extrusions) and the effect of radiation (particularly X-rays) on some of the allotropes. Mixtures of sulfur allotropes were produced in the laboratory by quenching molten sulfur and it was found that the spectra indicate the presence of certain red-colored allotropes which are preserved upon quenching. The color of the sulfur glass produced is redder when the temperature of the original melt is higher. This is consistent with the suggestion that Io's spectral geometric albedo can be partly explained by the presence of quenched sulfur glasses.

  8. Application of electrochemical investigation methods in high sulfur coal flotation

    SciTech Connect

    Zhu Hong; Ou Zeshen; Shi Xiuping; Shen Yanchun

    1997-12-31

    More and more attention has been paid to sulfur dioxide pollution caused by coal burning. It is important that sulfur in coal should be reduced before combustion. Flotation is an important method for the removal of pyrite from high sulfur coal. Many chemicals have been tested as a pyrite depressant. In recent years many tests have been done in the laboratory on the flotation behavior of pyrite, and the results have confirmed that the hydrophobicity of the pyrite surface is dependent on the redox potential of the pulp. The mechanism and the reaction products on the pyrite surface are discussed under various conditions. And pyrite depression in coal flotation by electrochemical control are further studied on the basis of what has been achieved. There are two methods in electrochemical control: chemical reagent and control potential by electrochemical instrument (``control potential`` for short). This paper studies pyrite depression in coal flotation by electrochemical control. The influence of sulfur removal in coal flotation has been probed by chemical reagent and control potential. Experiment shows that at low pulp potential the pyrite flotation is generally suppressed. This is new, efficient and simple method of pyrite depression without environmental pollution. The following main conclusions can be drawn from this study: (1) The control of pulp potential can regulate and lead to electrochemical reaction of the hydrophobicity or hydrophilicity on the pyrite surface; and (2) The characteristics of electrochemical methods are normal atmospheric temperature, simple technological process and strong selection.

  9. Designing high-energy lithium-sulfur batteries.

    PubMed

    Seh, Zhi Wei; Sun, Yongming; Zhang, Qianfan; Cui, Yi

    2016-10-21

    Due to their high energy density and low material cost, lithium-sulfur batteries represent a promising energy storage system for a multitude of emerging applications, ranging from stationary grid storage to mobile electric vehicles. This review aims to summarize major developments in the field of lithium-sulfur batteries, starting from an overview of their electrochemistry, technical challenges and potential solutions, along with some theoretical calculation results to advance our understanding of the material interactions involved. Next, we examine the most extensively-used design strategy: encapsulation of sulfur cathodes in carbon host materials. Other emerging host materials, such as polymeric and inorganic materials, are discussed as well. This is followed by a survey of novel battery configurations, including the use of lithium sulfide cathodes and lithium polysulfide catholytes, as well as recent burgeoning efforts in the modification of separators and protection of lithium metal anodes. Finally, we conclude with an outlook section to offer some insight on the future directions and prospects of lithium-sulfur batteries.

  10. Janus Separator of Polypropylene-Supported Cellular Graphene Framework for Sulfur Cathodes with High Utilization in Lithium-Sulfur Batteries.

    PubMed

    Peng, Hong-Jie; Wang, Dai-Wei; Huang, Jia-Qi; Cheng, Xin-Bing; Yuan, Zhe; Wei, Fei; Zhang, Qiang

    2016-01-01

    Owing to the conversion chemistry of the sulfur cathode, the lithium-sulfur (Li-S) batteries exhibit high theoretical energy density. However, the intrinsic mobile redox centers during the sulfur/Li2S-to-lithium polysulfides solid-to-liquid phase transition induce low sulfur utilization and poor cycling life. Herein, the Janus separator of mesoporous cellular graphene framework (CGF)/polypropylene membrane to promote the utilization of sulfur cathode is introduced. The porous polypropylene membrane serves as an insulating substrate in contact with lithium anode while CGFs that possess high electrical conductivity of 100 S cm(-1), a large mesopore volume of 3.1 cm(3) g(-1), and a huge surface area of 2120 m(2) g(-1) are adhered on cathode side to reactivate the shuttling-back polysulfides and to preserve the ion channels. Therefore, the Li-S cell with the "two-face" CGF Janus separator exhibit a high initial capacity of 1109 mAh g(-1) and superior capacity preserved upon 800 mAh g(-1) after 250 cycles at 0.2 C, which is 40% higher on sulfur utilization efficiency than the corresponding results with routine polypropylene separators. There are significant improvements on capacity as well as electrochemical kinetics. A very high areal capacity of 5.5 mAh cm(-2) combined with high sulfur content of 80% and areal loading amount of 5.3 mg cm(-2) is achieved for such advanced configuration. The negative impact of shuttle mechanism on lowering the utilization of sulfur and overall energy density of a Li-S battery is well eliminated by applying CGF separators. Consequently, employing carbonaceous materials as Janus face of separators enlightens new opportunities for improving the utilization of active materials and energy density of devices that involve complex phase evolution and conversion electrochemistry.

  11. Janus Separator of Polypropylene‐Supported Cellular Graphene Framework for Sulfur Cathodes with High Utilization in Lithium–Sulfur Batteries

    PubMed Central

    Peng, Hong‐Jie; Wang, Dai‐Wei; Cheng, Xin‐Bing; Yuan, Zhe; Wei, Fei

    2016-01-01

    Owing to the conversion chemistry of the sulfur cathode, the lithium–sulfur (Li–S) batteries exhibit high theoretical energy density. However, the intrinsic mobile redox centers during the sulfur/Li2S‐to‐lithium polysulfides solid‐to‐liquid phase transition induce low sulfur utilization and poor cycling life. Herein, the Janus separator of mesoporous cellular graphene framework (CGF)/polypropylene membrane to promote the utilization of sulfur cathode is introduced. The porous polypropylene membrane serves as an insulating substrate in contact with lithium anode while CGFs that possess high electrical conductivity of 100 S cm−1, a large mesopore volume of 3.1 cm3 g−1, and a huge surface area of 2120 m2 g−1 are adhered on cathode side to reactivate the shuttling‐back polysulfides and to preserve the ion channels. Therefore, the Li–S cell with the “two‐face” CGF Janus separator exhibit a high initial capacity of 1109 mAh g−1 and superior capacity preserved upon 800 mAh g−1 after 250 cycles at 0.2 C, which is 40% higher on sulfur utilization efficiency than the corresponding results with routine polypropylene separators. There are significant improvements on capacity as well as electrochemical kinetics. A very high areal capacity of 5.5 mAh cm−2 combined with high sulfur content of 80% and areal loading amount of 5.3 mg cm−2 is achieved for such advanced configuration. The negative impact of shuttle mechanism on lowering the utilization of sulfur and overall energy density of a Li–S battery is well eliminated by applying CGF separators. Consequently, employing carbonaceous materials as Janus face of separators enlightens new opportunities for improving the utilization of active materials and energy density of devices that involve complex phase evolution and conversion electrochemistry. PMID:27774384

  12. Sulfur-carbon nanocomposite cathodes improved by an amphiphilic block copolymer for high-rate lithium-sulfur batteries.

    PubMed

    Fu, Yongzhu; Su, Yu-Sheng; Manthiram, Arumugam

    2012-11-01

    A sulfur-carbon nanocomposite consisting of a commercial high-surface-area carbon (i.e., Black Pearls 2000, BET surface area >1000 m² g⁻¹) and sulfur has been synthesized by an in situ deposition method. The nanocomposite is in the form of agglomerated nanoparticles, with the micropores within the carbon filled with sulfur and the mesopores on the carbon surface almost completely covered by sulfur. The BET surface area of the nanocomposite containing a sulfur content of 63.5 wt % is significantly reduced to only 40 m² g⁻¹. Cathodes containing the nanocomposite and Pluronic F-127 block copolymer, which partially replaces the polyvinylidene fluoride binder, were prepared and evaluated in lithium cells by cyclic voltammetry and galvanostatic cycling. The nanocomposite cathodes with the copolymer show improved electrochemical stability and cyclability. The Pluronic copolymer helps retain a uniform nanocomposite structure within the electrodes, improving the electrochemical contact, which was manifested by scanning electron microscopy and electrochemical impedance spectroscopy. The sulfur-Black Pearls nanocomposite with the Pluronic copolymer as an additive in the electrodes is promising for high-rate rechargeable lithium-sulfur batteries.

  13. Sulfur-infiltrated graphene-based layered porous carbon cathodes for high-performance lithium-sulfur batteries.

    PubMed

    Yang, Xi; Zhang, Long; Zhang, Fan; Huang, Yi; Chen, Yongsheng

    2014-05-27

    Because of advantages such as excellent electronic conductivity, high theoretical specific surface area, and good mechanical flexibility, graphene is receiving increasing attention as an additive to improve the conductivity of sulfur cathodes in lithium-sulfur (Li-S) batteries. However, graphene is not an effective substrate material to confine the polysulfides in cathodes and stable the cycling. Here, we designed and synthesized a graphene-based layered porous carbon material for the impregnation of sulfur as cathode for Li-S battery. In this composite, a thin layer of porous carbon uniformly covers both surfaces of the graphene and sulfur is highly dispersed in its pores. The high specific surface area and pore volume of the porous carbon layers not only can achieve a high sulfur loading in highly dispersed amorphous state, but also can act as polysulfide reservoirs to alleviate the shuttle effect. When used as the cathode material in Li-S batteries, with the help of the thin porous carbon layers, the as-prepared materials demonstrate a better electrochemical performance and cycle stability compared with those of graphene/sulfur composites.

  14. A Sheet-like Carbon Matrix Hosted Sulfur as Cathode for High-performance Lithium-Sulfur Batteries

    PubMed Central

    Lu, Songtao; Chen, Yan; Zhou, Jia; Wang, Zhida; Wu, Xiaohong; Gu, Jian; Zhang, Xiaoping; Pang, Aimin; Jiao, Zilong; Jiang, Lixiang

    2016-01-01

    Lithium-sulfur (Li-S) batteries are a promising candidate of next generation energy storage systems owing to its high theoretical capacity and energy density. However, to date, its commercial application was hindered by the inherent problems of sulfur cathode. Additionally, with the rapid decline of non-renewable resources and active appeal of green chemistry, the intensive research of new electrode materials was conducted worldwide. We have obtained a sheet-like carbon material (shaddock peel carbon sheets SPCS) from organic waste shaddock peel, which can be used as the conductive carbon matrix for sulfur-based cathodes. Furthermore, the raw materials are low-cost, truly green and recyclable. As a result, the sulfur cathode made with SPCS (SPCS-S), can deliver a high reversible capacity of 722.5 mAh g−1 at 0.2 C after 100 cycles with capacity recuperability of ~90%, demonstrating that the SPCS-S hybrid is of great potential as the cathode for rechargeable Li-S batteries. The high electrochemical performance of SPCS-S hybrid could be attributed to the sheet-like carbon network with large surface area and high conductivity of the SPCS, in which the carbon sheets enable the uniform distribution of sulfur, better ability to trap the soluble polysulfides and accommodate volume expansion/shrinkage of sulfur during repeated charge/discharge cycles. PMID:26842015

  15. Hierarchical nitrogen-doped porous graphene/reduced fluorographene/sulfur hybrids for high-performance lithium-sulfur batteries.

    PubMed

    Liu, Zhixuan; Li, Jie; Xiang, Jingwei; Cheng, Shuai; Wu, Hao; Zhang, Na; Yuan, Lixia; Zhang, Wenfeng; Xie, Jia; Huang, Yunhui; Chang, Haixin

    2017-01-18

    It is a great challenge to obtain high performance cathodes with a high sulfur loading and good cycle performance due to the dissolution of intermediate lithium polysulfides in lithium-sulfur batteries. Herein, we report a novel hierarchical hybrid composed of nitrogen-doped porous graphene (NG), reduced fluorographene or graphene fluoride (RFG), and sulfur as a composite cathode in the Li-S batteries. In comparison with sulfur composites based on only either nitrogen-doped porous graphene or pure reduced fluorographene, the hierarchical hybrid of RFG, NG, and sulfur (NG-RFG/S) shows a better reversible capacity and rate capability performance due to a better confinement effect of lithium polysulfides and sulfur. The NG-RFG/S cathode with ∼63.2% S content exhibits a high discharge capacity of 1120 mA h g(-1) and retains 632 mA h g(-1) after 100 cycles at 0.1C. At the higher rate of 0.5C, the cell still maintains a discharge capacity of about 300 mA h g(-1) after 800 cycles, which reveals the great potential of this hybrid cathode for long-cycle-life, high energy density storage applications.

  16. Nitrogen, sulfur-codoped graphene sponge as electroactive carbon interlayer for high-energy and -power lithium-sulfur batteries

    NASA Astrophysics Data System (ADS)

    Xing, Ling-Bao; Xi, Kai; Li, Qiuyan; Su, Zhong; Lai, Chao; Zhao, Xinsheng; Kumar, R. Vasant

    2016-01-01

    Sulfur is an attractive cathode material in energy storage devices since its high theoretical capacity of 1672 mAh g-1. However, practical application of lithium sulfur (Li-S) batteries can be achieved only when the major barriers, including the insulating nature of element sulfur and shuttling effect of polysulfides (Li2Sx, x = 3-8), are tackled. Here, nitrogen, sulfur-codoped (N,S-codoped) sponge-like graphene, which presents a high reversible capacity, is used as electroactive interlayer for Li-S batteries to address these issues. An impressive high capacity of 2193.2 mAh g-1 can be obtained for the sulfur cathodes with such an interlayer at the rate of 0.2C, and it can be stably maintained at 829.4 mAh g-1 at the rate of 6C, for which the contribution from the electroactive interlayer is ca. 30.0%. High energy density of 418.5 Wh Kg-1 still can be released at the power density of 4.55 kW kg-1 (6C) based on the total mass of the sulfur cathode and interlayer for the assembled Li-S batteries.

  17. A Sheet-like Carbon Matrix Hosted Sulfur as Cathode for High-performance Lithium-Sulfur Batteries

    NASA Astrophysics Data System (ADS)

    Lu, Songtao; Chen, Yan; Zhou, Jia; Wang, Zhida; Wu, Xiaohong; Gu, Jian; Zhang, Xiaoping; Pang, Aimin; Jiao, Zilong; Jiang, Lixiang

    2016-02-01

    Lithium-sulfur (Li-S) batteries are a promising candidate of next generation energy storage systems owing to its high theoretical capacity and energy density. However, to date, its commercial application was hindered by the inherent problems of sulfur cathode. Additionally, with the rapid decline of non-renewable resources and active appeal of green chemistry, the intensive research of new electrode materials was conducted worldwide. We have obtained a sheet-like carbon material (shaddock peel carbon sheets SPCS) from organic waste shaddock peel, which can be used as the conductive carbon matrix for sulfur-based cathodes. Furthermore, the raw materials are low-cost, truly green and recyclable. As a result, the sulfur cathode made with SPCS (SPCS-S), can deliver a high reversible capacity of 722.5 mAh g‑1 at 0.2 C after 100 cycles with capacity recuperability of ~90%, demonstrating that the SPCS-S hybrid is of great potential as the cathode for rechargeable Li-S batteries. The high electrochemical performance of SPCS-S hybrid could be attributed to the sheet-like carbon network with large surface area and high conductivity of the SPCS, in which the carbon sheets enable the uniform distribution of sulfur, better ability to trap the soluble polysulfides and accommodate volume expansion/shrinkage of sulfur during repeated charge/discharge cycles.

  18. A Sheet-like Carbon Matrix Hosted Sulfur as Cathode for High-performance Lithium-Sulfur Batteries.

    PubMed

    Lu, Songtao; Chen, Yan; Zhou, Jia; Wang, Zhida; Wu, Xiaohong; Gu, Jian; Zhang, Xiaoping; Pang, Aimin; Jiao, Zilong; Jiang, Lixiang

    2016-02-04

    Lithium-sulfur (Li-S) batteries are a promising candidate of next generation energy storage systems owing to its high theoretical capacity and energy density. However, to date, its commercial application was hindered by the inherent problems of sulfur cathode. Additionally, with the rapid decline of non-renewable resources and active appeal of green chemistry, the intensive research of new electrode materials was conducted worldwide. We have obtained a sheet-like carbon material (shaddock peel carbon sheets SPCS) from organic waste shaddock peel, which can be used as the conductive carbon matrix for sulfur-based cathodes. Furthermore, the raw materials are low-cost, truly green and recyclable. As a result, the sulfur cathode made with SPCS (SPCS-S), can deliver a high reversible capacity of 722.5 mAh g(-1) at 0.2 C after 100 cycles with capacity recuperability of ~90%, demonstrating that the SPCS-S hybrid is of great potential as the cathode for rechargeable Li-S batteries. The high electrochemical performance of SPCS-S hybrid could be attributed to the sheet-like carbon network with large surface area and high conductivity of the SPCS, in which the carbon sheets enable the uniform distribution of sulfur, better ability to trap the soluble polysulfides and accommodate volume expansion/shrinkage of sulfur during repeated charge/discharge cycles.

  19. Nafion coated sulfur-carbon electrode for high performance lithium-sulfur batteries

    NASA Astrophysics Data System (ADS)

    Tang, Qiwei; Shan, Zhongqiang; Wang, Li; Qin, Xue; Zhu, Kunlei; Tian, Jianhua; Liu, Xuesheng

    2014-01-01

    In this paper, a nafion coated electrode is prepared to improve the performance of lithium sulfur batteries. It is demonstrated from a series of measurements that the nafion layer is quite effective in reducing shuttle effect and enhancing the stability and the reversibility of the electrode. When measured under the rate of 0.2 C, the initial discharge capacity of the nafion coated electrode can reach 1084 mAh g-1, with a Columbic efficiency of about 100%. After 100 charge/discharge cycles, this electrode can also deliver a reversible capacity of as high as 879 mAh g-1. Significantly, the charge-transfer resistance of the electrode tends to be reducing after coated with an appropriate thickness of nafion film. The cation conductivity as well as anion inconductivity is considered to be the dominant factor for the superior electrochemical properties.

  20. High-Resolution Multiple Sulfur Isotope Studies of Martian Meteorites

    NASA Technical Reports Server (NTRS)

    Mojzsis, S. J.

    2000-01-01

    Sensitive, high resolution measurements of S-32, S-31, and S-34 in individual pyrite grains in martian meteorite ALH84001 by an in situ ion microprobe multi-collection technique reveal mass-independent anomalies in Delta.S-33 (Delta.S-33 = delta.S-33 - 0.516delta.S-34) in addition to the lowest 634S found in an extraterrestrial material. Low delta.S-34 values in two pyrite grains intimately associated with carbonate in ALH84001 can be explained by the sensitivity of sulfur to fractionations in the geologic environment. Anomalies in Delta.S-33 recorded in ALH84001 pyrites probably formed by gas-phase reactions in the early martian atmosphere (>4 Ga). The discovery of clearly resolvable Delta-S33 anomalies in 2 of 12 ALH84001 pyrites analyzed in their petrographic context in thin section, is considered strong evidence for crust-atmosphere exchange and the global cycling of volatile sulfur species on early Mars. These results corroborate previous measurements by Farquhar and co-workers who used a different technique that measures that bulk Delta.S-33 values of martian meteorites. These independent techniques, and their results, suggest that sulfur affected by mass-independent fractionation is common on Mars.

  1. A binder-free sulfur/reduced graphene oxide aerogel as high performance electrode materials for lithium sulfur batteries.

    PubMed

    Nitze, Florian; Agostini, Marco; Lundin, Filippa; Palmqvist, Anders E C; Matic, Aleksandar

    2016-12-23

    Societies' increasing need for energy storage makes it necessary to explore new concepts beyond the traditional lithium ion battery. A promising candidate is the lithium-sulfur technology with the potential to increase the energy density of the battery by a factor of 3-5. However, so far the many problems with the lithium-sulfur system have not been solved satisfactory. Here we report on a new approach utilizing a self-standing reduced graphene oxide based aerogel directly as electrodes, i.e. without further processing and without the addition of binder or conducting agents. We can thereby disrupt the common paradigm of "no battery without binder" and can pave the way to a lithium-sulfur battery with a high practical energy density. The aerogels are synthesized via a one-pot method and consist of more than 2/3 sulfur, contained inside a porous few-layered reduced graphene oxide matrix. By combining the graphene-based aerogel cathode with an electrolyte and a lithium metal anode, we demonstrate a lithium-sulfur cell with high areal capacity (more than 3 mAh/cm(2) after 75 cycles), excellent capacity retention over 200 cycles and good sulfur utilization. Based on this performance we estimate that the energy density of this concept-cell can significantly exceed the Department of Energy (DEO) 2020-target set for transport applications.

  2. A binder-free sulfur/reduced graphene oxide aerogel as high performance electrode materials for lithium sulfur batteries

    PubMed Central

    Nitze, Florian; Agostini, Marco; Lundin, Filippa; Palmqvist, Anders E. C.; Matic, Aleksandar

    2016-01-01

    Societies’ increasing need for energy storage makes it necessary to explore new concepts beyond the traditional lithium ion battery. A promising candidate is the lithium-sulfur technology with the potential to increase the energy density of the battery by a factor of 3–5. However, so far the many problems with the lithium-sulfur system have not been solved satisfactory. Here we report on a new approach utilizing a self-standing reduced graphene oxide based aerogel directly as electrodes, i.e. without further processing and without the addition of binder or conducting agents. We can thereby disrupt the common paradigm of “no battery without binder” and can pave the way to a lithium-sulfur battery with a high practical energy density. The aerogels are synthesized via a one-pot method and consist of more than 2/3 sulfur, contained inside a porous few-layered reduced graphene oxide matrix. By combining the graphene-based aerogel cathode with an electrolyte and a lithium metal anode, we demonstrate a lithium-sulfur cell with high areal capacity (more than 3 mAh/cm2 after 75 cycles), excellent capacity retention over 200 cycles and good sulfur utilization. Based on this performance we estimate that the energy density of this concept-cell can significantly exceed the Department of Energy (DEO) 2020-target set for transport applications. PMID:28008981

  3. A binder-free sulfur/reduced graphene oxide aerogel as high performance electrode materials for lithium sulfur batteries

    NASA Astrophysics Data System (ADS)

    Nitze, Florian; Agostini, Marco; Lundin, Filippa; Palmqvist, Anders E. C.; Matic, Aleksandar

    2016-12-01

    Societies’ increasing need for energy storage makes it necessary to explore new concepts beyond the traditional lithium ion battery. A promising candidate is the lithium-sulfur technology with the potential to increase the energy density of the battery by a factor of 3–5. However, so far the many problems with the lithium-sulfur system have not been solved satisfactory. Here we report on a new approach utilizing a self-standing reduced graphene oxide based aerogel directly as electrodes, i.e. without further processing and without the addition of binder or conducting agents. We can thereby disrupt the common paradigm of “no battery without binder” and can pave the way to a lithium-sulfur battery with a high practical energy density. The aerogels are synthesized via a one-pot method and consist of more than 2/3 sulfur, contained inside a porous few-layered reduced graphene oxide matrix. By combining the graphene-based aerogel cathode with an electrolyte and a lithium metal anode, we demonstrate a lithium-sulfur cell with high areal capacity (more than 3 mAh/cm2 after 75 cycles), excellent capacity retention over 200 cycles and good sulfur utilization. Based on this performance we estimate that the energy density of this concept-cell can significantly exceed the Department of Energy (DEO) 2020-target set for transport applications.

  4. Hydroxylated N-doped carbon nanotube-sulfur composites as cathodes for high-performance lithium-sulfur batteries

    NASA Astrophysics Data System (ADS)

    Lee, Jun Seop; Manthiram, Arumugam

    2017-03-01

    Despite the higher energy density than the conventional Li-ion cells at a lower cost, commercialization of Lisbnd S batteries is hindered by the insulating nature of sulfur and the dissolution of intermediate polysulfides (Li2SX, 4 < X ≤ 8) into the electrolyte. We demonstrate here hydroxylated N-doped carbon nanotubes (H-NCNT) as sulfur containers in lithium-sulfur batteries to reduce polysulfide shuttling through an interaction between polysulfides and nitrogen and hydroxyl groups in the H-NCNT. This sulfur-carbon composite electrode with 2.2 mg cm-2 sulfur displays excellent performance with high rate capability (initial capacity of 1341 mAh g-1 at C/5 rate and 849 mAh g-1 at 5C rate), rate stability until 500 cycles (a decay of 0.06% per cycle). Furthermore, a stable reversible capacity of as high as ∼1081 mAh g-1 is realized with a higher sulfur loading of 5.1 mg cm-2.

  5. Leaf-Like Graphene-Oxide-Wrapped Sulfur for High-Performance Lithium-Sulfur Battery.

    PubMed

    Yuan, Shouyi; Guo, Ziyang; Wang, Lina; Hu, Shuang; Wang, Yonggang; Xia, Yongyao

    2015-08-01

    Carbon/sulfur composites are attracting extensive attention because of their improved performances for Li-S batteries. However, the achievements are generally based on the low S-content in the composites and the low S-loading on the electrode. Herein, a leaf-like graphene oxide (GO), which includes an inherent carbon nanotube midrib in the GO plane, is synthesized for preparing GO/S composites. Owing to the inherent high conductivity of carbon nanotube midribs and the abundant surface groups of GO for S-immobilization, the composite with an S-content of 60 wt% exhibits ultralong cycling stability over 1000 times with a low capacity decay of 0.033% per cycle and a high rate up to 4C. When the S-content is increased to 75 wt%, the composite still shows a perfect cycling performance over 1000 cycles. Even with the high S-loading of 2.7 mg cm(-2) on the electrode and the high S-content of 85 wt%, it still shows a promising cycling performance over 600 cycles.

  6. Nitrogen-doped graphene/sulfur composite as cathode material for high capacity lithium-sulfur batteries

    NASA Astrophysics Data System (ADS)

    Wang, Xiwen; Zhang, Zhian; Qu, Yaohui; Lai, Yanqing; Li, Jie

    2014-06-01

    Two types of nitrogen-doped graphene sheets (NGS) synthesized by a facile hydrothermal method are used to immobilize sulfur via an in situ sulfur deposition route. The structure and composition of the prepared nitrogen doped graphene/sulfur (NGS/S) composites are confirmed with X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. Scanning electron microscope (SEM) and Transmission electron microscope (TEM) images shows the porous sulfur particles are well wrapped by NGS. Compared with graphene/sulfur (GS/S) composite, the NGS-1/S composite with high loading (80 wt%) of sulfur presents a remarkably higher reversible capacity (1356.8 mAh g-1 at 0.1 C) and long cycle stability (578.5 mAh g-1 remaining at 1 C up to 500 cycles). Pyridinic-N rich NGS-1/S exhibits a better electrochemical performance than pyrrolic-N enriched NGS-2/S. The improvement of electrochemical properties could be attributed to the chemical interaction between the nitrogen functionalities on the surface of NGS and polysulfide as well as the enhanced electronic conductivity of the carbon matrix.

  7. Sulfur concentration of martian basalts at sulfide saturation at high pressures and temperatures - Implications for deep sulfur cycle on Mars

    NASA Astrophysics Data System (ADS)

    Ding, Shuo; Dasgupta, Rajdeep; Tsuno, Kyusei

    2014-04-01

    To constrain sulfur concentration at sulfide saturation (SCSS) of martian magmas at mantle conditions, we simulated basalt-sulfide melt equilibria using two synthesized meteorite compositions, i.e., Yamato980459 and NWA2990 in both anhydrous and hydrous conditions at 1-5 GPa and 1500-1700 °C. Our experimental results show that SCSS decreases with increasing pressure and increases with increasing temperature. Based on our experimental SCSS and those from previous low-pressure experiments on high-FeO∗ martian basalts, we developed a parameterization to predict martian basalt SCSS as a function of depth, temperature, and melt composition. Our model suggests that sulfur contents as high as 3500-4300 ppm can be transferred from the martian mantle to the martian exogenic system, and sulfur-rich gases might have caused the greenhouse conditions during the late Noachian. However, modeling of the behavior of sulfur along the liquid line of descent of a primitive martian basalt suggests that a fraction of the magmatic sulfur could precipitate as sulfides in the cumulates during cooling and fractional crystallization of basaltic magmas. Furthermore, the latter case is consistent with the S concentration of martian meteorites, which reflect variable amount of trapped liquid in cumulus mineral assemblage. Furthermore, our model predicts an average S storage capacity of 5700 ppm for the martian magma ocean, whereas the same for Earth is only ∼860 ppm. Lastly, high SCSS of martian magma ocean and its inverse correlation with depth along the mantle liquidus could have triggered a sulfur pump where the post-core-formation magma ocean of Mars would gain sulfur through interaction with SO2/H2S rich nascent atmosphere.

  8. Integrated Process Configuration for High-Temperature Sulfur Mitigation during Biomass Conversion via Indirect Gasification

    SciTech Connect

    Dutta. A.; Cheah, S.; Bain, R.; Feik, C.; Magrini-Bair, K.; Phillips, S.

    2012-06-20

    Sulfur present in biomass often causes catalyst deactivation during downstream operations after gasification. Early removal of sulfur from the syngas stream post-gasification is possible via process rearrangements and can be beneficial for maintaining a low-sulfur environment for all downstream operations. High-temperature sulfur sorbents have superior performance and capacity under drier syngas conditions. The reconfigured process discussed in this paper is comprised of indirect biomass gasification using dry recycled gas from downstream operations, which produces a drier syngas stream and, consequently, more-efficient sulfur removal at high temperatures using regenerable sorbents. A combination of experimental results from NREL's fluidizable Ni-based reforming catalyst, fluidizable Mn-based sulfur sorbent, and process modeling information show that using a coupled process of dry gasification with high-temperature sulfur removal can improve the performance of Ni-based reforming catalysts significantly.

  9. Process for removing sulfur from sulfur-containing gases: high calcium fly-ash

    DOEpatents

    Rochelle, Gary T.; Chang, John C. S.

    1991-01-01

    The present disclosure relates to improved processes for treating hot sulfur-containing flue gas to remove sulfur therefrom. Processes in accordance with the present invention include preparing an aqueous slurry composed of a calcium alkali source and a source of reactive silica and/or alumina, heating the slurry to above-ambient temperatures for a period of time in order to facilitate the formation of sulfur-absorbing calcium silicates or aluminates, and treating the gas with the heat-treated slurry components. Examples disclosed herein demonstrate the utility of these processes in achieving improved sulfur-absorbing capabilities. Additionally, disclosure is provided which illustrates preferred configurations for employing the present processes both as a dry sorbent injection and for use in conjunction with a spray dryer and/or bagfilter. Retrofit application to existing systems is also addressed.

  10. Aspergillus flavus Conidia-derived Carbon/Sulfur Composite as a Cathode Material for High Performance Lithium–Sulfur Battery

    NASA Astrophysics Data System (ADS)

    Xu, Maowen; Jia, Min; Mao, Cuiping; Liu, Sangui; Bao, Shujuan; Jiang, Jian; Liu, Yang; Lu, Zhisong

    2016-01-01

    A novel approach was developed to prepare porous carbon materials with an extremely high surface area of 2459.6 m2g‑1 by using Aspergillus flavus conidia as precursors. The porous carbon serves as a superior cathode material to anchor sulfur due to its uniform and tortuous morphology, enabling high capacity and good cycle lifetime in lithium sulfur-batteries. Under a current rate of 0.2 C, the carbon-sulfur composites with 56.7 wt% sulfur loading deliver an initial capacity of 1625 mAh g‑1, which is almost equal to the theoretical capacity of sulfur. The good performance may be ascribed to excellent electronic networks constructed by the high-surface-area carbon species. Moreover, the semi-closed architecture of derived carbons can effectively retard the polysulfides dissolution during charge/discharge, resulting in a capacity of 940 mAh g‑1 after 120 charge/discharge cycles.

  11. SULFUR DIOXIDE - SULFUR TRIOXIDE REGENERATIVE FUEL CELL RESEARCH

    DTIC Science & Technology

    The thermodynamics and electrolytic characteristics are discussed of an SO2-SO3 regenerative, closed-cycle fuel cell , and summarizes the electrolytic...electrochemical, and phase separation research conducted during a study program to determine the practicability of such a fuel cell . The...experimental results obtained were at such wide variance with the theoretical concept that it became apparent that a fuel cell of this type is not feasible. (Author)

  12. High sulfur related thiamine deficiency in cattle: A field study

    PubMed Central

    Gooneratne, S. Ravi; Olkowski, Andrzej A.; Klemmer, Robert G.; Kessler, Gerald A.; Christensen, David A.

    1989-01-01

    Following development of polioencephalomalacia in one of 105 cattle in a farm in southeastern Saskatchewan, a study was initiated to monitor thiamine (B1) and copper (Cu) status, and to evaluate interactive nutritional factors which may have been responsible for this occurrence. It was evident that a combination of high sulfur (S) and low Cu intake was responsible for the depletion of blood B1 and plasma Cu. Supplementation with trace minerals alone resulted in a significant (p<0.05) improvement in both B1 and Cu status of the herd. We recommend that herds exposed to high intakes of S be supplemented with Cu up to 50 mg/kg feed dry matter to alleviate potential deficiencies of B1 and Cu. ImagesFigure 1.Figure 2. PMID:17423233

  13. New infrared transmitting material via inverse vulcanization of elemental sulfur to prepare high refractive index polymers.

    PubMed

    Griebel, Jared J; Namnabat, Soha; Kim, Eui Tae; Himmelhuber, Roland; Moronta, Dominic H; Chung, Woo Jin; Simmonds, Adam G; Kim, Kyung-Jo; van der Laan, John; Nguyen, Ngoc A; Dereniak, Eustace L; Mackay, Michael E; Char, Kookheon; Glass, Richard S; Norwood, Robert A; Pyun, Jeffrey

    2014-05-21

    Polymers for IR imaging: The preparation of high refractive index polymers (n = 1.75 to 1.86) via the inverse vulcanization of elemental sulfur is reported. High quality imaging in the near (1.5 μm) and mid-IR (3-5 μm) regions using high refractive index polymeric lenses from these sulfur materials was demonstrated.

  14. Cellulose acetate-based composites with antimicrobial properties from embedded molybdenum trioxide particles.

    PubMed

    Shafaei, S; Dörrstein, J; Guggenbichler, J P; Zollfrank, C

    2017-01-01

    The objective of this research was to develop novel cellulose acetate (biopolymer) composite materials with an excellent antimicrobial activity by embedding molybdenum trioxide particles with unique high specific surface area. High surface area molybdenum trioxide particles were prepared from freshly precipitated molybdenum trioxide dihydrate (MoO3 ·2H2 O) and subsequent calcination at 340°C under H2 /N2 gas. Microbiological evaluation against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa were performed applying a roll-on test and excellent antimicrobial activities were determined for composites with embedded anhydrous molybdenum trioxide with a high specific surface area. Cellulose acetate composites comprising MoO3 particles can eliminate three harmful bacteria as a result of the release of protons from the material and surface enlargement of the molybdenum trioxide particles. The findings support a proposed antimicrobial mechanism based on local acidity increase due to large specific surface areas.

  15. Sulfur Encapsulated in Graphitic Carbon Nanocages for High-Rate and Long-Cycle Lithium-Sulfur Batteries.

    PubMed

    Zhang, Juan; Yang, Chun-Peng; Yin, Ya-Xia; Wan, Li-Jun; Guo, Yu-Guo

    2016-11-01

    Hybrid sp(2) carbon with a graphene backbone and graphitic carbon nanocages (G-GCNs) is demonstrated as an ideal host for sulfur in Li-S batteries, because it serves as highly efficient electrochemical nanoreactors as well as polysulfides reservoirs. The as-obtained S/(G-GCNs) with high S content exhibits superior high-rate capability (765 mA h g(-1) at 5 C) and long-cycle life over 1000 cycles.

  16. [Determination of the content of sulfur of coal by the infrared absorption method with high acccuracy].

    PubMed

    Wang, Hai-Feng; Lu, Hai; Li, Jia; Sun, Guo-Hua; Wang, Jun; Dai, Xin-Hua

    2014-02-01

    The present paper reported the differential scanning calorimetry-thermogravimetry curves and the infrared (IR) absorption spectrometry under the temperature program analyzed by the combined simultaneous thermal analysis-IR spectrometer. The gas products of coal were identified by the IR spectrometry. This paper emphasized on the combustion at high temperature-IR absorption method, a convenient and accurate method, which measures the content of sulfur in coal indirectly through the determination of the content of sulfur dioxide in the mixed gas products by IR absorption. It was demonstrated, when the instrument was calibrated by varied pure compounds containing sulfur and certified reference materials (CRMs) for coal, that there was a large deviation in the measured sulfur contents. It indicates that the difference in chemical speciations of sulfur between CRMs and the analyte results in a systematic error. The time-IR absorption curve was utilized to analyze the composition of sulfur at low temperatures and high temperatures and then the sulfur content of coal sample was determined by using a CRM for coal with a close composition of sulfur. Therefore, the systematic error due to the difference in chemical speciations of sulfur between the CRM and analyte was eliminated. On the other hand, in this combustion at high temperature-IR absorption method, the mass of CRM and analyte were adjusted to assure the sulfur mass equal and then the CRM and the analyte were measured alternately. This single-point calibration method reduced the effect of the drift of the IR detector and improved the repeatability of results, compared with the conventional multi-point calibration method using the calibration curves of signal intensity vs sulfur mass. The sulfur content results and their standard deviations of an anthracite coal and a bituminous coal with a low sulfur content determined by this modified method were 0.345% (0.004%) and 0.372% (0.008%), respectively. The uncertainty (U

  17. Sulfur Nanogranular Film-Coated Three-Dimensional Graphene Sponge-Based High Power Lithium Sulfur Battery.

    PubMed

    Ahn, Wook; Seo, Min Ho; Jun, Yun-Seok; Lee, Dong Un; Hassan, Fathy M; Wang, Xiaolei; Yu, Aiping; Chen, Zhongwei

    2016-01-27

    To meet the requirements of both high energy and power density with cycle durability of modern EVs, we prepared a novel nanosulfur granular assembled film coated on the three-dimensional graphene sponge (3D-GS) composite as a high-performance active material for rechargeable lithium sulfur batteries. Instead of conventional graphene powder, three-dimensional rGO sponge (3D-rGO) is employed for the composite synthesis, resulting in a sulfur film directly in contact with the underlying graphene layer. This significantly improves the overall electrical conductivity, strategically addressing challenges of conventional composites of low sulfur utilization and dissolution of polysulfides. Additionally, the synthesis mechanism of 3D-GS is elucidated by XPS and DFT analyses, where replacement of hydroxyl group of 3D-rGO sponge by sulfur (S8) is found to be thermodynamically favorable. As expected, 3D-GS demonstrates outstanding discharge capacity of 1080 mAh g(-1) at a 0.1C rate, and 86.2% capacity retention even after 500 cycles at a 1.0C rate.

  18. Behavior of sulfur at high pressures and low temperatures. [transition to high electroconductivity state

    NASA Technical Reports Server (NTRS)

    Golopentia, D. A.; Ruoff, A. L.

    1981-01-01

    A new type of high-pressure apparatus for low-temperature experiments was built, which allows loading and measuring the load in situ at low temperature (1.5 K). It uses the diamond anvil in the flat-indentor configuration. It was used to investigate the high-conductivity state of sulfur at low temperatures. For pressures in the 50-GPa range, sulfur is still a semiconductor or at best a two phase semiconductor-metal system. As the temperature is lowered at 50 GPa, the resistance drops slightly, reaches a minimum around 230 deg K, and then increases dramatically.

  19. The solubility of sulfur in high-TiO2 mare basalts

    NASA Technical Reports Server (NTRS)

    Danckwerth, P. A.; Hess, P. C.; Rutherford, M. J.

    1979-01-01

    The present paper deals with an experimental investigation of the solubility of sulfur of the high-TiO2 mare basalt 74275 at 1 atm, 1250 C. The data indicate that at saturation, 74275 is capable of dissolving 3400 ppm sulfur at 10 to 15 degrees below its liquidus. The analyzed samples of 74275 show sulfur contents of 1650 ppm S, which indicates that 74275 was 50% undersaturated at the time of eruption.

  20. Pressure and high-Tc superconductivity in sulfur hydrides

    PubMed Central

    Gor’kov, Lev P.; Kresin, Vladimir Z.

    2016-01-01

    The paper discusses fundamentals of record-TC superconductivity discovered under high pressure in sulfur hydride. The rapid increase of TC with pressure in the vicinity of Pcr ≈ 123GPa is interpreted as the fingerprint of a first-order structural transition. Based on the cubic symmetry of the high-TC phase, it is argued that the lower-TC phase has a different periodicity, possibly related to an instability with a commensurate structural vector. In addition to the acoustic branches, the phonon spectrum of H3S contains hydrogen modes with much higher frequencies. Because of the complex spectrum, usual methods of calculating TC are here inapplicable. A modified approach is formulated and shown to provide realistic values for TC and to determine the relative contributions of optical and acoustic branches. The isotope effect (change of TC upon Deuterium for Hydrogen substitution) originates from high frequency phonons and differs in the two phases. The decrease of TC following its maximum in the high-TC phase is a sign of intermixing with pairing at hole-like pockets which arise in the energy spectrum of the cubic phase at the structural transition. On-pockets pairing leads to the appearance of a second gap and is remarkable for its non-adiabatic regime: hydrogen mode frequencies are comparable to the Fermi energy. PMID:27167334

  1. Sodium-sulfur cells with high conductivity glass electrolytes

    NASA Astrophysics Data System (ADS)

    Nelson, P. A.; Bloom, I.; Bradley, J.; Roche, M. F.

    1985-05-01

    A study is under way to develop glasses in the soda-alumina-zirconia-silica system that have high conductivity for sodium ions. Sodium-conductivity and corrosion experiments indicate that the target resistivity of 100 ohm-cm at 300(0)C can be achieved for glasses having satisfactory corrosion resistance for use in sodium-sulfur cells. The low resistivity makes possible a unique approach to cell design. Cells of 150 A-hr capacity were designed having 6-mm dia electrolytes and are expected to achieve a specific energy of up to 270 W-hr/kg. Others having 1.5-mm dia electrolytes are expected to attain a specific power of up to 2 or 3 kW/kg. Excellent heat removal can be provided for high-specific-power cells by short metallic paths from the center of the cell to the cooled cell wall. Reliability of the cell may be achieved by: (1) use of a protective tube around each electrolyte tube to protect against failure propagation, and (2) the provision for automatic disconnection of a failed element by burnout of its current collector wire.

  2. Demonstration of Selective Catalytic Reduction Technology to Control Nitrogen Oxide Emissions From High-Sulfur, Coal-Fired Boilers: A DOE Assessment

    SciTech Connect

    Federal Energy Technology Center

    1999-12-01

    The goal of the U.S. Department of Energy (DOE) Clean Coal Technology (CCT) program is to furnish the energy marketplace with a number of advanced, more efficient, and environmentally responsible coal utilization technologies through demonstration projects. These projects seek to establish the commercial feasibility of the most promising advanced coal technologies that have developed beyond the proof-of-concept stage. This document serves as a DOE post-project assessment of a project selected in CCT Round 2. The project is described in the report ''Demonstration of Selective Catalytic Reduction (SCR) Technology for the Control of Nitrogen Oxide (NO{sub x}) Emissions from High-Sulfur, Coal-Fired Boilers'' (Southern Company Services 1990). In June 1990, Southern Company Services (Southern) entered into a cooperative agreement to conduct the study. Southern was a cofunder and served as the host at Gulf Power Company's Plant Crist. Other participants and cofunders were EPRI (formerly the Electric Power Research Institute) and Ontario Hydro. DOE provided 40 percent of the total project cost of $23 million. The long-term operation phase of the demonstration was started in July 1993 and was completed in July 1995. This independent evaluation is based primarily on information from Southern's Final Report (Southern Company Services 1996). The SCR process consists of injecting ammonia (NH{sub 3}) into boiler flue gas and passing the 3 flue gas through a catalyst bed where the NO{sub x} and NH{sub 3} react to form nitrogen and water vapor. The objectives of the demonstration project were to investigate: Performance of a wide variety of SCR catalyst compositions, geometries, and manufacturing methods at typical U.S. high-sulfur coal-fired utility operating conditions; Catalyst resistance to poisoning by trace metal species present in U.S. coals but not present, or present at much lower concentrations, in fuels from other countries; and Effects on the balance-of-plant equipment

  3. Sulfur-graphene nanostructured cathodes via ball-milling for high-performance lithium-sulfur batteries.

    PubMed

    Xu, Jiantie; Shui, Jianglan; Wang, Jianli; Wang, Min; Liu, Hua-Kun; Dou, Shi Xue; Jeon, In-Yup; Seo, Jeong-Min; Baek, Jong-Beom; Dai, Liming

    2014-10-28

    Although much progress has been made to develop high-performance lithium-sulfur batteries (LSBs), the reported physical or chemical routes to sulfur cathode materials are often multistep/complex and even involve environmentally hazardous reagents, and hence are infeasible for mass production. Here, we report a simple ball-milling technique to combine both the physical and chemical routes into a one-step process for low-cost, scalable, and eco-friendly production of graphene nanoplatelets (GnPs) edge-functionalized with sulfur (S-GnPs) as highly efficient LSB cathode materials of practical significance. LSBs based on the S-GnP cathode materials, produced by ball-milling 70 wt % sulfur and 30 wt % graphite, delivered a high initial reversible capacity of 1265.3 mAh g(-1) at 0.1 C in the voltage range of 1.5-3.0 V with an excellent rate capability, followed by a high reversible capacity of 966.1 mAh g(-1) at 2 C with a low capacity decay rate of 0.099% per cycle over 500 cycles, outperformed the current state-of-the-art cathode materials for LSBs. The observed excellent electrochemical performance can be attributed to a 3D "sandwich-like" structure of S-GnPs with an enhanced ionic conductivity and lithium insertion/extraction capacity during the discharge-charge process. Furthermore, a low-cost porous carbon paper pyrolyzed from common filter paper was inserted between the 0.7S-0.3GnP electrode and porous polypropylene film separator to reduce/eliminate the dissolution of physically adsorbed polysulfide into the electrolyte and subsequent cross-deposition on the anode, leading to further improved capacity and cycling stability.

  4. High-temperature sorbent method for removal of sulfur containing gases from gaseous mixtures

    DOEpatents

    Young, John E.; Jalan, Vinod M.

    1984-01-01

    A copper oxide-zinc oxide mixture is used as a sorbent for removing hydrogen sulfide and other sulfur containing gases at high temperatures from a gaseous fuel mixture. This high-temperature sorbent is especially useful for preparing fuel gases for high temperature fuel cells. The copper oxide is initially reduced in a preconditioning step to elemental copper and is present in a highly dispersed state throughout the zinc oxide which serves as a support as well as adding to the sulfur sorption capacity. The spent sorbent is regenerated by high-temperature treatment with an air fuel, air steam mixture followed by hydrogen reduction to remove and recover the sulfur.

  5. High-temperature sorbent method for removal of sulfur containing gases from gaseous mixtures

    DOEpatents

    Young, J.E.; Jalan, V.M.

    1984-06-19

    A copper oxide-zinc oxide mixture is used as a sorbent for removing hydrogen sulfide and other sulfur containing gases at high temperatures from a gaseous fuel mixture. This high-temperature sorbent is especially useful for preparing fuel gases for high temperature fuel cells. The copper oxide is initially reduced in a preconditioning step to elemental copper and is present in a highly dispersed state throughout the zinc oxide which serves as a support as well as adding to the sulfur sorption capacity. The spent sorbent is regenerated by high-temperature treatment with an air fuel, air steam mixture followed by hydrogen reduction to remove and recover the sulfur.

  6. High-temperature sorbent method for removal of sulfur-containing gases from gaseous mixtures

    DOEpatents

    Young, J.E.; Jalan, V.M.

    1982-07-07

    A copper oxide-zinc oxide mixture is used as a sorbent for removing hydrogen sulfide and other sulfur containing gases at high temperatures from a gaseous fuel mixture. This high-temperature sorbent is especially useful for preparing fuel gases for high temperature fuel cells. The copper oxide is initially reduced in a preconditioning step to elemental copper and is present in a highly dispersed state throughout the zinc oxide which serves as a support as well as adding to the sulfur sorbtion capacity. The spent sorbent is regenerated by high-temperature treatment with an air fuel, air steam mixture followed by hydrogen reduction to remove and recover the sulfur.

  7. A Fluorinated Ether Electrolyte Enabled High Performance Prelithiated Graphite/Sulfur Batteries.

    PubMed

    Chen, Shuru; Yu, Zhaoxin; Gordin, Mikhail L; Yi, Ran; Song, Jiangxuan; Wang, Donghai

    2017-03-01

    Lithium/sulfur (Li/S) batteries have attracted great attention as a promising energy storage technology, but so far their practical applications are greatly hindered by issues of polysulfide shuttling and unstable lithium/electrolyte interface. To address these issues, a feasible strategy is to construct a rechargeable prelithiated graphite/sulfur batteries. In this work, a fluorinated ether of bis(2,2,2-trifluoroethyl) ether (BTFE) was reported to blend with 1,3-dioxolane (DOL) for making a multifunctional electrolyte of 1.0 M LiTFSI DOL/BTFE (1:1, v/v) to enable high performance prelithiated graphite/S batteries. First, the electrolyte significantly reduces polysulfide solubility to suppress the deleterious polysulfide shuttling and thus improves capacity retention of sulfur cathodes. Second, thanks to the low viscosity and good wettability, the fluorinated electrolyte dramatically enhances the reaction kinetics and sulfur utilization of high-areal-loading sulfur cathodes. More importantly, this electrolyte forms a stable solid-electrolyte interphase (SEI) layer on graphite surface and thus enables remarkable cyclability of graphite anodes. By coupling prelithiated graphite anodes with sulfur cathodes with high areal capacity of ∼3 mAh cm(-2), we demonstrate prelithiated graphite/sulfur batteries that show high sulfur-specific capacity of ∼1000 mAh g(-1) and an excellent capacity retention of >65% after 450 cycles at C/10.

  8. Nano-structured electrocatalysts for high performance lithium sulfur batteries

    NASA Astrophysics Data System (ADS)

    Mosavati, Negar

    Ni nanoparticles has been investigated as a carbon-free cathode material for dissolved polysulfide Li-S battery. A series of Ni nanoparticles with nominal particle size of 20, 40, and 100 nm have been used as electrocatalysts, and the effect of particle size on Li-S battery performance has been investigated. In addition, graphene has been chosen as a support to anchor the Ni nanoparticles, and the synergetic effect of carbon material and Ni nanoparticles on Li-S battery electrochemical performance has been studied. The results indicated there is a strong particle size effect. Ni/graphene electrode exhibits a capacity of 753 mAh g-1 sulfur after 40 cycles due to its high conductivity and electrocatalytic activity toward polysulfide reduction reaction. This capacity is significantly higher than similar studies. Based on the understanding of the electrocathalytic effect of Ni and capacity fading mechanism, transition metal nitrides has been investigated as a new class of cathode materials. Titanium nitride (TiN) nanoparticle was studied as a novel cathode material for Li/dissolved polysulfide batteries. In addition, X-ray photoelectron spectroscopy (XPS) analysis was used to obtain a deeper understanding of the mechanism underlying polysulfide conversion reactions with TiN cathode, and during charge and discharge processes. TiN exhibited a superior performance in a Li/dissolved polysulfide battery configuration. Knowing the superior performance of TiN, the study was expanded to different transition metal nitrides to investigate the role of surface composition and morphology in enhancing the electrochemical performance of Li-S batteries. WN, Mo2N, and VN were synthesized and the electrochemical performance, surface composition, and oxidation/reduction mechanism of these cathodes electrodes were studied for lithium sulfur batteries. Understanding the fading mechanisms of dissolved polysulfide system for metal nitride cathodes, It was tried to enhance Li-S battery

  9. Preparation of three-dimensional hybrid nanostructure-encapsulated sulfur cathode for high-rate lithium sulfur batteries

    NASA Astrophysics Data System (ADS)

    Xie, Jing; Yang, Juan; Zhou, Xiangyang; Zou, Youlan; Tang, Jingjing; Wang, Songcan; Chen, Feng

    2014-05-01

    A three-dimensional hybrid nanostructure incorporating the merits of the MWCNTs webs (MWCNTs-W) and the reduced graphene oxide (RGO) is designed to improve the high-rate cycling performance of the lithium-sulfur batteries. Owing to the excellent Li+ ion and electronic transport properties of the MWCNTs-W and the RGO, this unique structure can provide a three-dimensional conductive network and promote rapid charge-transfer reaction at the cathode. Furthermore, because of the rough surface and porous structure of the MWCNTs after activation with KOH, and the special adsorption ability of the RGO, the soluble polysulfide intermediates can be effectively trapped in the cathode. Therefore, when evaluating the electrochemical properties of the RGO@MWCNTs-W/S composite as the cathode material for lithium-sulfur batteries, it exhibits an excellent cyclical stability and high rate performance. In particular, even at an ultrahigh rate (5 C), a discharge capacity as high as 620 mAh g-1 is still retained for the RGO@MWCNTs-W/S composite with 68.93 wt% sulfur after 200 cycles, and the average coulombic efficiency is 96%.

  10. Sulfur removal from high-sulfur Illinois coal by low-temperature perchloroethylene (PCE) extraction. Technical report, December 1, 1991--February 29, 1992

    SciTech Connect

    Chou, M.I.M; Lytle, J.M.; Ruch, R.R.; Kruse, C.W.; Chaven, C.; Hackley, K.C.; Hughes, R.E.; Harvey, R.D.; Frost, J.K.; Buchanan, D.H.; Stucki, J.W.; Huffman, G.; Huggins, F.E.

    1992-09-01

    A pre-combustion coal desulfurization process at 120{degree}C using perchloroethylene (PCE) to remove up to 70% of the organic sulfur has been developed by the Midwest Ore Processing Co. (MWOPC). However, this process has not yet proven to be as successful with Illinois coals as it has for Ohio and Indiana coals. In addition, the high levels of organic sulfur removals observed by the MWOPC may be due to certain errors involved in the ASTM data interpretation; this needs verification. For example, elemental sulfur extracted by the PCE may be derived from pyrite oxidation during coal preoxidation, but it may be interpreted as organic sulfur removed by the PCE using ASTM analysis. The purposes of this research are to independently confirm and possibly to improve the organic sulfur removal from Illinois coals with the PCE desulfurization process reported by the MWOPC and to verify the forms-of-sulfur determination using the ASTM method for the PCE process evaluation.

  11. Mildly reduced less defective graphene oxide/sulfur/carbon nanotube composite films for high-performance lithium-sulfur batteries.

    PubMed

    Li, Rui; Zhang, Miao; Li, Yingru; Chen, Ji; Yao, Bowen; Yu, Mingpeng; Shi, Gaoquan

    2016-04-28

    The microstructures and properties of the carbonaceous matrices in the cathodes of lithium-sulfur (Li-S) batteries have strong effects on their performances. We prepared a ternary composite cathode of mildly reduced less defective graphene oxide (mrLGO), sulfur, and carbon nanotubes (CNTs) by filtration for Li-S batteries. This battery showed a high initial specific capacity of 1219 mA h g(-1) at 0.2 C and a stable specific capacity of around 1000 mA h g(-1) after 200 cycles with a coulombic efficiency of 99%. Its excellent performance is mainly attributed to the good conductivity and residual oxygen containing groups of mrLGO, and the three-dimensional (3D) framework constructed using mrLGO sheets and CNTs.

  12. Extraction, separation, and analysis of high sulfur coal

    SciTech Connect

    Olesik, S.V.; Pekay, L.A.; Larkins, W. Jr.

    1992-05-31

    The work described in this report studies the removal of sulfur by oxidative interaction of various cupric salts with coal and also considers the possibility of removing organic sulfur by the selective interaction of supercritical ethanol with the organic coal matrix. Either one of these methods could potentially be used to pretreat coals before burning. The primary purpose of these studies is to ascertain the nature of the chemical reactions occurring, the chemical composition of the resultant products, and information on possible reaction mechanisms. This information should allow prediction of reasonable reaction conditions for the removal of organosulfur compound from coal.

  13. Extraction, separation, and analysis of high sulfur coal. Final report

    SciTech Connect

    Olesik, S.V.; Pekay, L.A.; Larkins, W. Jr.

    1992-05-31

    The work described in this report studies the removal of sulfur by oxidative interaction of various cupric salts with coal and also considers the possibility of removing organic sulfur by the selective interaction of supercritical ethanol with the organic coal matrix. Either one of these methods could potentially be used to pretreat coals before burning. The primary purpose of these studies is to ascertain the nature of the chemical reactions occurring, the chemical composition of the resultant products, and information on possible reaction mechanisms. This information should allow prediction of reasonable reaction conditions for the removal of organosulfur compound from coal.

  14. Production of low-sulfur binder pitch from high-sulfur Illinois coals. Technical report, September 1--November 30, 1994

    SciTech Connect

    Knight, R.A.

    1994-12-31

    The objective of this project is to produce electrode binder pitch with sulfur content below 0.6 wt% from high-sulfur Illinois coal mild gasification liquids. In this project, two approaches to sulfur reduction are being explored in conjunction with thermocracking: (1) the use of conventionally cleaned coal with low ({approximately}1%) sulfur as a mild gasification feedstock, and (2) direct biodesulfurization of the liquids prior to thermocracking. In Case 1, the crude pitch is being produced by mild gasification of IBC-109 coal in an existing IGT bench-scale reactor, followed by distillation of the scrubbing solvent and light-to-middle oils to isolate the crude pitch. In Case 2, the crude pitch for biodesulfurization is the same material previously studied, which was obtained from Illinois No. 6 coal tests conducted in the IGT mild gasification PRU in 1990. Biodesulfurization is to be performed by contacting the pitch with Rhodococcus Rhodochrous either as live cultures or in the form of concentrated biocatalyst. Following preparation of the crude pitches, pitch upgrading experiments are to be conducted in a continuous flash thermocracker (FTC) constructed in previous ICCI-sponsored studies. The finished pitch is then characterized for physical and chemical properties (density, softening point, QI, TI, coking value, and elemental composition), and compared to typical specifications for binder pitches. This quarter, 45 kg of IBC-109 coal was obtained and sized to 40 x 80 mesh for mild gasification. Laboratory experiments were conducted to identify means of dispersing or emulsifying pitch in water to render is accessible to biocatalysts, and exploratory desulfurization tests on one-gram pitch samples were begun.

  15. High resistance to sulfur poisoning of Ni with copper skin under electric field

    NASA Astrophysics Data System (ADS)

    Xu, Xiaopei; Zhang, Yanxing; Yang, Zongxian

    2017-02-01

    The effects of sulfur poisoning on the (1 0 0), (1 1 0) and (1 1 1) surfaces of pure Ni and Cu/Ni alloy are studied in consideration of the effect of electric field. The effects of Cu dopants on the S poisoning characteristics are analyzed by the means of the density functional theory results in combination with thermodynamics data using the ab initio atomistic thermodynamic method. When the Cu concentration increases to 50% on the surface layer of the Cu/Ni alloy, the (1 1 0) surface becomes the most vulnerable to the sulfur poisoning. Ni with a copper skin can mostly decrease the sulfur poisoning effect. Especially under the electric field of 1.0 V/Å, the sulfur adsorption and phase transition temperature can be further reduced. We therefore propose that Ni surfaces with copper skin can be very effective to improve the resistance to sulfur poisoning of the Ni anode under high electric field.

  16. Compatibility and Decontamination of High-Density Polyethylene Exposed to Sulfur Mustard

    DTIC Science & Technology

    2014-05-01

    COMPATIBILITY AND DECONTAMINATION OF HIGH-DENSITY POLYETHYLENE EXPOSED TO SULFUR MUSTARD ECBC-TR-1235...Decontamination of High-Density Polyethylene Exposed to Sulfur Mustard 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S...study to determine the compatability of high-density polyethylene (HDPE) with liquid mustard (HD) material and decontamination of HDPE when exposed

  17. EXTRACTION AND QUANTITATIVE ANALYSIS OF ELEMENTAL SULFUR FROM SULFIDE MINERAL SURFACES BY HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY. (R826189)

    EPA Science Inventory

    A simple method for the quantitative determination of elemental sulfur on oxidized sulfide minerals is described. Extraction of elemental sulfur in perchloroethylene and subsequent analysis with high-performance liquid chromatography were used to ascertain the total elemental ...

  18. Sulfur removal from high-sulfur Illinois coal by low-temperature perchloroethylene (PCE) extraction. Annual report, September 1, 1991--August 31, 1992

    SciTech Connect

    Chou, M.I.M.; Lytle, J.M.; Ruch, R.R.; Kruse, C.W.; Chaven, C.; Hackley, K.C.; Hughes, R.E.; Harvey, R.D.; Frost, J.K.; Buchanan, D.H.; Stucki, J.W.; Huffman, G.P.; Huggins, F.E.; Banerjee, D.D.

    1992-12-31

    The Midwest Ore Processing Co. (MWOPC) has reported a precombustion coal desulfurization process using perchloroethylene (PCE) at 120{degree}C to remove up to 70% of the organic sulfur. However, this process has not been proven to be as successful with Illinois coals as it has been for Ohio and Indiana coals. Also, the high levels of organic sulfur removals observed by the MWOPC may be due to certain errors involved in interpreting data from the American Society For Testing and Materials (ASTM) method for forms-of-sulfur analysis. The purposes of this research are to independently confirm and possibly to improve the organic sulfur removal from Illinois coals with the PCE desulfurization process and to verify the forms-of-sulfur determination using the ASTM method for evaluation of the PCE process. One problem that limits commercial application of the PCE process is the high chlorine content in the PCE-treated coals. Hence, an additional goal of this investigation is to develop a dechlorination procedure to remove excess PCE from the PCE-treated coal. MWOPC`s results have been repeated on our tests for the fresh IBC-104 coal. Oxidation of coals was found to affect subsequent PCE desulfurization. Elemental sulfur is more amenable than organic sulfur to removal by PCE. Ohio 5/6 coal appears to produce elemental sulfur more readily than Illinois coal during oxidation.

  19. High Performance All-Solid-State Flexible Micro-Pseudocapacitor Based on Hierarchically Nanostructured Tungsten Trioxide Composite

    PubMed Central

    2015-01-01

    Microsupercapacitors (MSCs) are promising energy storage devices to power miniaturized portable electronics and microelectromechanical systems. With the increasing attention on all-solid-state flexible supercapacitors, new strategies for high-performance flexible MSCs are highly desired. Here, we demonstrate all-solid-state, flexible micropseudocapacitors via direct laser patterning on crack-free, flexible WO3/polyvinylidene fluoride (PVDF)/multiwalled carbon nanotubes (MWCNTs) composites containing high levels of porous hierarchically structured WO3 nanomaterials (up to 50 wt %) and limited binder (PVDF, <25 wt %). The work leads to an areal capacitance of 62.4 mF·cm–2 and a volumetric capacitance of 10.4 F·cm–3, exceeding that of graphene based flexible MSCs by a factor of 26 and 3, respectively. As a noncarbon based flexible MSC, hierarchically nanostructured WO3 in the narrow finger electrode is essential to such enhancement in energy density due to its pseudocapacitive property. The effects of WO3/PVDF/MWCNTs composite composition and the dimensions of interdigital structure on the performance of the flexible MSCs are investigated. PMID:26618406

  20. High Performance All-Solid-State Flexible Micro-Pseudocapacitor Based on Hierarchically Nanostructured Tungsten Trioxide Composite.

    PubMed

    Huang, Xuezhen; Liu, Hewei; Zhang, Xi; Jiang, Hongrui

    2015-12-23

    Microsupercapacitors (MSCs) are promising energy storage devices to power miniaturized portable electronics and microelectromechanical systems. With the increasing attention on all-solid-state flexible supercapacitors, new strategies for high-performance flexible MSCs are highly desired. Here, we demonstrate all-solid-state, flexible micropseudocapacitors via direct laser patterning on crack-free, flexible WO3/polyvinylidene fluoride (PVDF)/multiwalled carbon nanotubes (MWCNTs) composites containing high levels of porous hierarchically structured WO3 nanomaterials (up to 50 wt %) and limited binder (PVDF, <25 wt %). The work leads to an areal capacitance of 62.4 mF·cm(-2) and a volumetric capacitance of 10.4 F·cm(-3), exceeding that of graphene based flexible MSCs by a factor of 26 and 3, respectively. As a noncarbon based flexible MSC, hierarchically nanostructured WO3 in the narrow finger electrode is essential to such enhancement in energy density due to its pseudocapacitive property. The effects of WO3/PVDF/MWCNTs composite composition and the dimensions of interdigital structure on the performance of the flexible MSCs are investigated.

  1. Durable polydopamine-coated porous sulfur core-shell cathode for high performance lithium-sulfur batteries

    NASA Astrophysics Data System (ADS)

    Deng, Yuanfu; Xu, Hui; Bai, Zhaowen; Huang, Baoling; Su, Jingyang; Chen, Guohua

    2015-12-01

    Lithium-sulfur batteries show fascinating potential for advanced energy system due to their high specific capacity, low-cost, and environmental benignity. However, their wide applications have been plagued by low coulombic efficiency, fast capacity fading and poor rate performance. Herein, a facile method for preparation of S@PDA (PDA = polydopamine) composites with core-shell structure and good electrochemical performance as well as the First-Principles calculations on the interactions of PDA and polysulfides are reported. Taking the advantages of the core-shell structure with porous sulfur core, the high mechanical flexibility of PDA for accommodating the volumetric variation during the discharge/charge processes, the good lithium ion conductivity and the strong chemical interactions between the nitrogen/oxygen atoms with lone electron pair and lithium polysulfides for alleviating their dissolution, the S@PDA composites exhibit high discharge capacities at different current densities (1048 and 869 mAh g-1 at 0.2 and 0.8 A g-1, respectively) and excellent capacity retention capability. A capacity decay as low as 0.021% per cycle and an average coulombic efficiency of 98.5% is observed over a long-term cycling of 890 cycles at 0.8 A g-1. The S@PDA electrode has great potential as a low-cost cathode in high energy Li-S batteries.

  2. Extraction, separation, and analysis of high sulfur coal

    SciTech Connect

    Olesik, S.V.

    1991-01-01

    Two processes were studied in the period. The first was a study of oxidative desulfurization processes. Earlier research indicated that the use of copper-promoted oxidation of the organic and inorganic sulfur species in coal showed considerable promise. Initial studies utilizing CuCl{sub 2} demonstrated that the desulfurization yields were much lower than previously quoted. However, the experiments suggested that the reactant pathway showed promise and further investigations were conducted varying the solvent and replacing the Cl{sup {minus}} anion with the OH{sup {minus}} species. Ultimate analyses of these reactions are reported in addition to the experimental conditions used. Reactions using Cu(OH){sub 2}, CuCl{sub 2}, and copper cyclohexane butyrate are investigated. The second process discussed was desulfurization using selective solvation. Supercritical ethanol was used to investigate the extent of organic sulfur removal from coal. (VC)

  3. A highly efficient polysulfide mediator for lithium-sulfur batteries

    NASA Astrophysics Data System (ADS)

    Liang, Xiao; Hart, Connor; Pang, Quan; Garsuch, Arnd; Weiss, Thomas; Nazar, Linda F.

    2015-01-01

    The lithium-sulfur battery is receiving intense interest because its theoretical energy density exceeds that of lithium-ion batteries at much lower cost, but practical applications are still hindered by capacity decay caused by the polysulfide shuttle. Here we report a strategy to entrap polysulfides in the cathode that relies on a chemical process, whereby a host—manganese dioxide nanosheets serve as the prototype—reacts with initially formed lithium polysulfides to form surface-bound intermediates. These function as a redox shuttle to catenate and bind ‘higher’ polysulfides, and convert them on reduction to insoluble lithium sulfide via disproportionation. The sulfur/manganese dioxide nanosheet composite with 75 wt% sulfur exhibits a reversible capacity of 1,300 mA h g-1 at moderate rates and a fade rate over 2,000 cycles of 0.036%/cycle, among the best reported to date. We furthermore show that this mechanism extends to graphene oxide and suggest it can be employed more widely.

  4. A highly efficient polysulfide mediator for lithium-sulfur batteries.

    PubMed

    Liang, Xiao; Hart, Connor; Pang, Quan; Garsuch, Arnd; Weiss, Thomas; Nazar, Linda F

    2015-01-06

    The lithium-sulfur battery is receiving intense interest because its theoretical energy density exceeds that of lithium-ion batteries at much lower cost, but practical applications are still hindered by capacity decay caused by the polysulfide shuttle. Here we report a strategy to entrap polysulfides in the cathode that relies on a chemical process, whereby a host--manganese dioxide nanosheets serve as the prototype--reacts with initially formed lithium polysulfides to form surface-bound intermediates. These function as a redox shuttle to catenate and bind 'higher' polysulfides, and convert them on reduction to insoluble lithium sulfide via disproportionation. The sulfur/manganese dioxide nanosheet composite with 75 wt% sulfur exhibits a reversible capacity of 1,300 mA h g(-1) at moderate rates and a fade rate over 2,000 cycles of 0.036%/cycle, among the best reported to date. We furthermore show that this mechanism extends to graphene oxide and suggest it can be employed more widely.

  5. 3D coral-like nitrogen-sulfur co-doped carbon-sulfur composite for high performance lithium-sulfur batteries

    PubMed Central

    Wu, Feng; Li, Jian; Tian, Yafen; Su, Yuefeng; Wang, Jing; Yang, Wen; Li, Ning; Chen, Shi; Bao, Liying

    2015-01-01

    3D coral-like, nitrogen and sulfur co-doped mesoporous carbon has been synthesized by a facile hydrothermal-nanocasting method to house sulfur for Li–S batteries. The primary doped species (pyridinic-N, pyrrolic-N, thiophenic-S and sulfonic-S) enable this carbon matrix to suppress the diffusion of polysulfides, while the interconnected mesoporous carbon network is favourable for rapid transport of both electrons and lithium ions. Based on the synergistic effect of N, S co-doping and the mesoporous conductive pathway, the as-fabricated C/S cathodes yield excellent cycling stability at a current rate of 4 C (1 C = 1675 mA g−1) with only 0.085% capacity decay per cycle for over 250 cycles and ultra-high rate capability (693 mAh g−1 at 10 C rate). These capabilities have rarely been reported before for Li-S batteries. PMID:26288961

  6. Effects of Arsenic Trioxide on Minor Progressive High-Grade Osteosarcoma of the Extremities Metastatic to the Lung: Results of 39 Patients Treated in a Single Institution

    PubMed Central

    Xie, Lu; Guo, Wei; Tang, Xiaodong; Yang, Yi; Xu, Jie

    2016-01-01

    Patients who mildly progressed after first-line chemotherapy were administered arsenic trioxide (ATO) 5–10 mg intravenously daily. Thirty-nine patients were finally enrolled in the study, of whom 19 patients received first-line chemotherapy with ATO infusion while 20 patients did not. Progression-free survival at 4 months was 89.2 and 62.7% (p = 0.043) for the ATO group and the control group, respectively, while the 2-year overall survival was 61 and 16.4% (p = 0.032). PMID:27920692

  7. Producing vapor grown carbon fibers with high sulfur coal without SO{sub 2} emissions

    SciTech Connect

    Alig, R.; Lake, M.; Guth, J.; Burton, D.

    1995-12-31

    This paper describes the development of a unique process that produces a highly graphitic, vapor grown carbon fiber (VGCF) from the gas phase in pound quantities. Past vapor grown carbon fiber progress has stagnated because the iron catalyst did not grow filaments profusely enough to make a practical continuous reactor. It has been found that adding H{sub 2}S at an equimolar level with the iron catalyst, the filament formation vastly increases. Coal is desirable as a sulfur source, for it eliminates the need for handling toxic H{sub 2}S, and it is a very low cost hydrocarbon supply for the process. We show that Ohio, high-sulfur coal containing 2.5 to 4.6% sulfur accomplishes both tasks. There is also evidence that sulfur from the coal remains with the carbon fiber catalyst during the reaction and does not exhaust as SO{sub 2} into the atmosphere.

  8. Highly Cyclable Lithium-Sulfur Batteries with a Dual-Type Sulfur Cathode and a Lithiated Si/SiOx Nanosphere Anode.

    PubMed

    Lee, Sang-Kyu; Oh, Seung-Min; Park, Eunjun; Scrosati, Bruno; Hassoun, Jusef; Park, Min-Sik; Kim, Young-Jun; Kim, Hansu; Belharouak, Ilias; Sun, Yang-Kook

    2015-05-13

    Lithium-sulfur batteries could become an excellent alternative to replace the currently used lithium-ion batteries due to their higher energy density and lower production cost; however, commercialization of lithium-sulfur batteries has so far been limited due to the cyclability problems associated with both the sulfur cathode and the lithium-metal anode. Herein, we demonstrate a highly reliable lithium-sulfur battery showing cycle performance comparable to that of lithium-ion batteries; our design uses a highly reversible dual-type sulfur cathode (solid sulfur electrode and polysulfide catholyte) and a lithiated Si/SiOx nanosphere anode. Our lithium-sulfur cell shows superior battery performance in terms of high specific capacity, excellent charge-discharge efficiency, and remarkable cycle life, delivering a specific capacity of ∼750 mAh g(-1) over 500 cycles (85% of the initial capacity). These promising behaviors may arise from a synergistic effect of the enhanced electrochemical performance of the newly designed anode and the optimized layout of the cathode.

  9. Engineering of Hollow Core-Shell Interlinked Carbon Spheres for Highly Stable Lithium-Sulfur Batteries.

    PubMed

    Sun, Qiang; He, Bin; Zhang, Xiang-Qian; Lu, An-Hui

    2015-08-25

    We report engineered hollow core-shell interlinked carbon spheres that consist of a mesoporous shell, a hollow void, and an anchored carbon core and are expected to be ideal sulfur hosts for overcoming the shortage of Li-S batteries. The hollow core-shell interlinked carbon spheres were obtained through solution synthesis of polymer spheres followed by a pyrolysis process that occurred in the hermetical silica shell. During the pyrolysis, the polymer sphere was transformed into the carbon core and the carbonaceous volatiles were self-deposited on the silica shell due to the blocking effect of the hermetical silica shell. The gravitational force and the natural driving force of lowering the surface energy tend to interlink the carbon core and carbon/silica shell, resulting in a core-shell interlinked structure. After the SiO2 shell was etched, the mesoporous carbon shell was generated. When used as the sulfur host for Li-S batteries, such a hierarchical structure provides access to Li(+) ingress/egress for reactivity with the sulfur and, meanwhile, can overcome the limitations of low sulfur loading and a severe shuttle effect in solid carbon-supported sulfur cathodes. Transmission electron microscopy and scanning transmission electron microscopy images provide visible evidence that sulfur is well-encapsulated in the hollow void. Importantly, such anchored-core carbon nanostructures can simultaneously serve as a physical buffer and an electronically connecting matrix, which helps to realize the full potential of the active materials. Based on the many merits, carbon-sulfur cathodes show a high utilization of sulfur with a sulfur loading of 70 wt % and exhibit excellent cycling stability (i.e., 960 mA h g(-1) after 200 cycles at a current density of 0.5 C).

  10. A high-density graphene-sulfur assembly: a promising cathode for compact Li-S batteries.

    PubMed

    Zhang, Chen; Liu, Dong-Hai; Lv, Wei; Wang, Da-Wei; Wei, Wei; Zhou, Guang-Min; Wang, Shaogang; Li, Feng; Li, Bao-Hua; Kang, Feiyu; Yang, Quan-Hong

    2015-03-19

    This work reports a high-density graphene/sulfur assembly for compact Li-S batteries with high volumetric capacity, which retains good structural stability and conductivity. This dense assembly was prepared by a reduction-triggered self-assembly of graphene oxide with simultaneous deposition of sulfur, followed by unique evaporation-induced spatial volume shrinkage. This assembly has an ultrahigh density, delivering an unprecedented volumetric capacity that is much higher than common carbon/sulfur cathodes. In particular, the unique spatial confinement derived from the shrinkage of the graphene/sulfur assembly is favorable for stabilizing sulfur cathodes.

  11. Multidimensional Polycation β-Cyclodextrin Polymer as an Effective Aqueous Binder for High Sulfur Loading Cathode in Lithium-Sulfur Batteries.

    PubMed

    Zeng, Fanglei; Wang, Weikun; Wang, Anbang; Yuan, Keguo; Jin, Zhaoqing; Yang, Yu-sheng

    2015-12-02

    Although the lithium-sulfur battery has attracted significant attention because of its high theoretical energy density and low cost of elemental sulfur, its real application is still hindered by multiple challenges, especially the polysulfides shuttled between the cathode and anode electrodes. By originating from β-cyclodextrin and introducing a quaternary ammonium cation into β-cyclodextrin polymer, a new multifunctional aqueous polycation binder (β-CDp-N(+)) for the sulfur cathode is obtained. The unique hyperbranched network structure of the new binder β-CDp-N(+) as well as its multidimensional noncovalent interactions and the introduced cations endowed β-CDp-N(+) with some new abilities: a sulfur-electrode-stabilized ability, a polysulfides-immobilized ability, and a volume-accommodated ability, which help to ease the primary problems of the lithium-sulfur battery, i.e., the shuttle of polysulfides and the volume change of the sulfur during charge and discharge. It is demonstrated that cycling performance and rate capability of the cathodes can be the improved by using β-CDp-N(+) as the binder compared to other well-known binders. Even with high sulfur loading of 5.5 mg cm(-2), the cathode with β-CDp-N(+) still can deliver an areal capacity of 4.4 mAh cm(-2) at 50 mA g(-1) after 45 cycles, which is much higher than that achieved using the cathode with the conventional binder (0.9 mAh cm(-2)).

  12. 3D Porous Graphene Aerogel Cathode with High Sulfur Loading and Embedded TiO2 Nanoparticles for Advanced Lithium-Sulfur Batteries.

    PubMed

    Huang, Jian-Qiu; Wang, Zhenyu; Xu, Zheng-Long; Chong, Woon Gie; Qin, Xianying; Wang, Xiangyu; Kim, Jang-Kyo

    2016-10-07

    Three-dimensional graphene aerogel/TiO2/sulfur (GA/TiO2/S) composites are synthesized through a facile, one-pot hydrothermal route as the cathode for lithium-sulfur batteries. With a high sulfur content of 75.1 wt%, the conductive, highly porous composite electrode delivers a high discharge capacity of 512 mAh/g after 250 cycles at a current rate of 1 C with a low capacity decay of 0.128% per cycle. The excellent capacities and cyclic stability arise from several unique functional features of the cathode. (i) The conductive graphene aerogel framework ameliorates ion/electron transfer while accommodating the volume expansion induced during discharge; and (ii) TiO2 nanoparticles play an important role in restricting the dissolution of polysulfides by chemical bonds with sulfur.

  13. Recovery of high purity sulfuric acid from the waste acid in toluene nitration process by rectification.

    PubMed

    Song, Kai; Meng, Qingqiang; Shu, Fan; Ye, Zhengfang

    2013-01-01

    Waste sulfuric acid is a byproduct generated from numerous industrial chemical processes. It is essential to remove the impurities and recover the sulfuric acid from the waste acid. In this study the rectification method was introduced to recover high purity sulfuric acid from the waste acid generated in toluene nitration process by using rectification column. The waste acid quality before and after rectification were evaluated using UV-Vis spectroscopy, GC/MS, HPLC and other physical and chemical analysis. It was shown that five nitro aromatic compounds in the waste acid were substantially removed and high purity sulfuric acid was also recovered in the rectification process at the same time. The COD was removed by 94% and the chrominance was reduced from 1000° to 1°. The recovered sulfuric acid with the concentration reaching 98.2 wt% had a comparable quality with commercial sulfuric acid and could be recycled back into the toluene nitration process, which could avoid waste of resources and reduce the environmental impact and pollution.

  14. Sulfur Cycle

    NASA Technical Reports Server (NTRS)

    Hariss, R.; Niki, H.

    1985-01-01

    Among the general categories of tropospheric sulfur sources, anthropogenic sources have been quantified the most accurately. Research on fluxes of sulfur compounds from volcanic sources is now in progress. Natural sources of reduced sulfur compounds are highly variable in both space and time. Variables, such as soil temperature, hydrology (tidal and water table), and organic flux into the soil, all interact to determine microbial production and subsequent emissions of reduced sulfur compounds from anaerobic soils and sediments. Available information on sources of COS, CS2, DMS, and H2S to the troposphere in the following paragraphs are summarized; these are the major biogenic sulfur species with a clearly identified role in tropospheric chemistry. The oxidation of SO2 to H2SO4 can often have a significant impact on the acidity of precipitation. A schematic representation of some important transformations and sinks for selected sulfur species is illustrated.

  15. Sulphur trioxide absorption apparatus and process

    SciTech Connect

    Cameron, G.M.

    1987-03-31

    This patent describes a contact process for producing a concentrated sulphuric acid from dry sulphur dioxide and oxygen containing mixtures which employs the absorption of sulphur trioxide from a hot, dry gas stream containing sulphur trioxide into at least one sulphuric acid stream. The improvement described here comprises: (a) feeding the gas stream to a lower packed absorption zone contained within an absorption tower; (b) feeding a first sulphuric acid stream to the lower absorption zone to effect absorption of a major portion of the sulphur trioxide from the gas stream into the first sulphuric acid stream to produce a first enriched sulphuric acid stream and a depleted sulphur trioxide gas stream; (c) feeding the depleted sulphur trioxide gas stream to an upper packed absorption zone above the lower absorption zone within the tower; and (d) feeding a second sulphuric acid stream to the upper absorption zone to effect absorption of substantially all of the sulphur trioxide remaining in the depleted sulphur trioxide gas stream to produce a second enriched sulphuric acid stream and a substantially sulphur trioxide-free gas stream.

  16. Safe and Durable High-Temperature Lithium-Sulfur Batteries via Molecular Layer Deposited Coating.

    PubMed

    Li, Xia; Lushington, Andrew; Sun, Qian; Xiao, Wei; Liu, Jian; Wang, Biqiong; Ye, Yifan; Nie, Kaiqi; Hu, Yongfeng; Xiao, Qunfeng; Li, Ruying; Guo, Jinghua; Sham, Tsun-Kong; Sun, Xueliang

    2016-06-08

    Lithium-sulfur (Li-S) battery is a promising high energy storage candidate in electric vehicles. However, the commonly employed ether based electrolyte does not enable to realize safe high-temperature Li-S batteries due to the low boiling and flash temperatures. Traditional carbonate based electrolyte obtains safe physical properties at high temperature but does not complete reversible electrochemical reaction for most Li-S batteries. Here we realize safe high temperature Li-S batteries on universal carbon-sulfur electrodes by molecular layer deposited (MLD) alucone coating. Sulfur cathodes with MLD coating complete the reversible electrochemical process in carbonate electrolyte and exhibit a safe and ultrastable cycle life at high temperature, which promise practicable Li-S batteries for electric vehicles and other large-scale energy storage systems.

  17. Graphene/sulfur hybrid nanosheets from a space-confined "sauna" reaction for high-performance lithium-sulfur batteries.

    PubMed

    Fei, Linfeng; Li, Xiaogang; Bi, Wentuan; Zhuo, Zhiwen; Wei, Wenfei; Sun, Li; Lu, Wei; Wu, Xiaojun; Xie, Keyu; Wu, Changzheng; Chan, Helen L W; Wang, Yu

    2015-10-21

    A space-confined "sauna" reaction system is introduced for the simultaneous reduction and functionalization of graphene oxide to unique graphene-sulfur hybrid nanosheets, in which thin layers of amorphous sulfur are tightly anchored on the graphene sheet via strong chemical bonding. Upon being used as the cathode material in lithium-sulfur batteries, the as-synthesized composite shows an excellent electrochemical performance.

  18. Hollow carbon nanofiber-encapsulated sulfur cathodes for high specific capacity rechargeable lithium batteries.

    PubMed

    Zheng, Guangyuan; Yang, Yuan; Cha, Judy J; Hong, Seung Sae; Cui, Yi

    2011-10-12

    Sulfur has a high specific capacity of 1673 mAh/g as lithium battery cathodes, but its rapid capacity fading due to polysulfides dissolution presents a significant challenge for practical applications. Here we report a hollow carbon nanofiber-encapsulated sulfur cathode for effective trapping of polysulfides and demonstrate experimentally high specific capacity and excellent electrochemical cycling of the cells. The hollow carbon nanofiber arrays were fabricated using anodic aluminum oxide (AAO) templates, through thermal carbonization of polystyrene. The AAO template also facilitates sulfur infusion into the hollow fibers and prevents sulfur from coating onto the exterior carbon wall. The high aspect ratio of the carbon nanofibers provides an ideal structure for trapping polysulfides, and the thin carbon wall allows rapid transport of lithium ions. The small dimension of these nanofibers provides a large surface area per unit mass for Li(2)S deposition during cycling and reduces pulverization of electrode materials due to volumetric expansion. A high specific capacity of about 730 mAh/g was observed at C/5 rate after 150 cycles of charge/discharge. The introduction of LiNO(3) additive to the electrolyte was shown to improve the Coulombic efficiency to over 99% at C/5. The results show that the hollow carbon nanofiber-encapsulated sulfur structure could be a promising cathode design for rechargeable Li/S batteries with high specific energy.

  19. High sulfur coal research at the SIUC Coal Technology Laboratory. Quarterly progress report

    SciTech Connect

    Not Available

    1984-01-01

    The research effort addressed in this cooperative agreement includes the conduct of a high-sulfur coal research program and the establishment of a research facility, the Coal Technology Laboratory at the site of the former Carbondale Mining Technology Center. The associated research program is broadly based and directed toward high-sulfur coal, the goal being expand the technology to allow for the increased use of high-sulfur coal in an environmentally acceptable manner. Progress continues to be made on the research in the four areas of coal science, coal preparation, coal conversion, and coal utilization. In the Coal Science area, the maceral separation laboratory is about 90% operational. In the area of coal preparation, a mechanical auger feeder device for introducing material into an experimental hydrocyclone along its axis was constructed and incorporated. A froth flotation pilot plant has been acquired and renovated. Coal conversion studies included experiments to examine the effects of chemical pretreatment on supercritical extraction and desulfurization of coal. It was found that with pretreatment a high-sulfur coal containing predominantly organic sulfur experienced a 57% reduction in sulfur on a concentration basis. Without pretreatment, the sulfur reduction was only 40%. In the work examining the mechanism of hydrogen sulfide formation from iron sulfides, it was found that hydrogen sulfide is formed from hydrogen and iron sulfides by a Langmuir-Hinselwood mechanism. Mixtures of H/sub 2/ and D/sub 2/ produce (H,D)H/sub 2/S with random distributions of H and D. Preliminary studies have been conducted in a 10 cm diameter laboratory scale AFBC unit preparatory to the tests to be conducted on waste fuels.

  20. Extraction, separation, and analysis of high sulfur coal

    SciTech Connect

    Olesik, S.

    1990-01-01

    The work completed this past quarter has centered around the further study and characterization of the selective desulfurization of coal through the oxidative interaction of aqueous copper chloride. The reaction of the CuCl{sub 2} with the particular model compounds is conducted at a series of reaction times and reaction temperatures. The reaction times studied were 1, 3, 6, 12, and 24 hours. The reaction temperatures studied were 50, 130, 210, and 295{degree}C. After the reaction, the organic compounds were extracted with methylene chloride. These products were then analyzed via GC/IRD/MS and SFC/SCD (sulfur chemiluminescence detector). Model Coal Compounds reacted include: tetrahydrothiophene, methyl p-tolyl sulfide, cyclohexyl mercaptan, and thiophenol. At 130{degree}C, in addition to these compounds reacting, reactions were also detected for phenyl sulfide and benzo(b)thiophene. 14 figs.

  1. A New Type of Multifunctional Polar Binder: Toward Practical Application of High Energy Lithium Sulfur Batteries.

    PubMed

    Chen, Wei; Qian, Tao; Xiong, Jie; Xu, Na; Liu, Xuejun; Liu, Jie; Zhou, Jinqiu; Shen, Xiaowei; Yang, Tingzhou; Chen, Yu; Yan, Chenglin

    2017-03-01

    A new type of amino polar binder with 3D network flexibility structure for high energy Li-S batteries is synthesized and successfully used with commercial sulfur powder cathodes. The binder shows significant performance improvement in capacity retention and high potential for practical application, which arouse the battery community's interest in the commercial application of high energy Li-S battery.

  2. Production of low-sulfur binder pitch from high-sulfur Illinois coals. Technical report, December 1, 1994--February 28, 1995

    SciTech Connect

    Knight, R.A.

    1996-03-01

    The objective of this project is to produce electrode binder pitch with sulfur content below 0.6 wt% from high-sulfur Illinois coal mild gasification liquids. In previous ICCI projects at IGT, flash thermocracking (FTC) was used to successfully upgrade the properties of mild gasification pitch, yielding a suitable blending stock for use as a binder in the production of carbon electrodes for the aluminum industry. However, in pitches from high-sulfur (4%) Illinois coal, the pitch sulfur content is still unacceptably high at 2%. In this project, two approaches to sulfur reduction are being explored in conjunction with FTC: (1) the use of conventionally cleaned coal with low ({approximately}1%) sulfur as a mild gasification feedstock, and (2) direct biodesulfurization of the liquids prior to FTC. In Case 1, the crude pitch is being produced by mild gasification of IBC-109 coal in an existing IGT bench-scale reactor, followed by distillation to isolate the crude pitch. In Case 2, the crude pitch for biodesulfurization was obtained from Illinois No. 6 coal tests conducted in the IGT mild gasification PRU in 1990. Biodesulfurization is to be performed by contacting the pitch with Rhodococcus Rhodochrous IGTS8 biocatalyst. Following preparation of the crude pitches, pitch upgrading experiments are to be conducted in a continuous FTC reactor constructed in previous ICCI-sponsored studies. The finished pitch is then characterized for physical and chemical properties (density, softening point, QI, TI, coking value, and elemental composition), and compared to typical specifications for binder pitches.

  3. Mesoporous carbon spheres with controlled porosity for high-performance lithium-sulfur batteries

    NASA Astrophysics Data System (ADS)

    Wang, Dexian; Fu, Aiping; Li, Hongliang; Wang, Yiqian; Guo, Peizhi; Liu, Jingquan; Zhao, Xiu Song

    2015-07-01

    Mesoporous carbon (MC) spheres with hierarchical pores, controlled pore volume and high specific surface areas have been prepared by a mass-producible spray drying assisted template method using sodium alginate as carbon precursor and commercial colloidal silica particles as hard template. The resulting MC spheres, possessing hierarchical pores in the range of 3-30 nm, are employed as conductive matrices for the preparation of cathode materials for lithium-sulfur batteries. A high pressure induced one-step impregnation of elemental sulfur into the pore of the MC spheres has been exploited. The electrochemical performances of sulfur-impregnated MC spheres (S-MC) derived from MC spheres with different pore volume and specific surface area but with the same sulfur loading ratio of 60 wt% (S-MC-X-60) have been investigated in details. The S-MC-4-60 composite cathode material displayed a high initial discharge capacity of 1388 mAhg-1 and a good cycling stability of 857 mAhg-1 after 100 cycles at 0.2C, and shows also excellent rate capability of 864 mAhg-1 at 2C. More importantly, the sulfur loading content in MC-4 spheres can reach as high as 80%, and it still can deliver a capacity of 569 mAhg-1 after 100 cycles at 0.2C.

  4. Permselective graphene oxide membrane for highly stable and anti-self-discharge lithium-sulfur batteries.

    PubMed

    Huang, Jia-Qi; Zhuang, Ting-Zhou; Zhang, Qiang; Peng, Hong-Jie; Chen, Cheng-Meng; Wei, Fei

    2015-03-24

    Lithium-sulfur batteries hold great promise for serving as next generation high energy density batteries. However, the shuttle of polysulfide induces rapid capacity degradation and poor cycling stability of lithium-sulfur cells. Herein, we proposed a unique lithium-sulfur battery configuration with an ultrathin graphene oxide (GO) membrane for high stability. The oxygen electronegative atoms modified GO into a polar plane, and the carboxyl groups acted as ion-hopping sites of positively charged species (Li(+)) and rejected the transportation of negatively charged species (Sn(2-)) due to the electrostatic interactions. Such electrostatic repulsion and physical inhibition largely decreased the transference of polysulfides across the GO membrane in the lithium-sulfur system. Consequently, the GO membrane with highly tunable functionalization properties, high mechanical strength, low electric conductivity, and facile fabrication procedure is an effective permselective separator system in lithium-sulfur batteries. By the incorporation of a permselective GO membrane, the cyclic capacity decay rate is also reduced from 0.49 to 0.23%/cycle. As the GO membrane blocks the diffusion of polysulfides through the membrane, it is also with advantages of anti-self-discharge properties.

  5. Production of low sulfur binder pitich from high-sulfur Illinois coals. Quarterly report, 1 March 1995--31 May 1995

    SciTech Connect

    Knight, R.A.

    1995-12-31

    The objective of this project is to produce electrode binder pitch with sulfur content below 0.6 wt% from high-sulfur Illinois coal mild gasification liquids. Previously, flash thermocracking (FTC) was used to successfully upgrade the properties of mild gasification pitch, yielding a suitable blending stock for use as a binder in the production of carbon electrodes for the aluminum industry. However, in pitches from high-sulfur (4%) Illinois coal, the pitch sulfur content (2%) was still higher than preferred. In this project two approaches to sulfur reduction are being explored in conjunction with FTC: (1) the use of a moderate-sulfur (1.2%) Illinois coal as mild gasification feedstock, and (2) direct biodesulfurization of the liquids from high-sulfur coal prior to FTC. In Case 1, the liquids are being produced by mild gasification of IBC-109 coal in a bench-scale fluidized-bed reactor, followed by distillation to isolate the crude pitch. In Case 2, biodesulfurization with Rhodococcus Rhodochrous IGTS8 biocatalyst is being performed on crude pitch obtained from Illinois No. 6 coal tests conducted in the IGT MILDGAS PRU in 1990. Following preparation of the crude pitches, pitch upgrading experiments are being conducted in a continuous FTC reactor constructed in previous ICCI-sponsored studies. This quarter, mild gasification of IBC-109 coal was completed, producing 450 g of coal liquids, which were then distilled to recover 329 g of Case 1 crude pitch. Next month, the pitch will be subjected to FTC treatment and evaluated. Biodesulfurization experiments were performed on Case 2 pitch dispersed in l-undecanol, resulting in sulfur reductions of 15.1 to 21.4%. This was marginally lower than the 24.8% desulfurization obtained in l-dodecanol, but separation of pitch from the dispersant was facilitated by the greater volatility of l-undecanol.

  6. Sulfur removal from high-sulfur Illinois coal by low-temperature perchloroethylene (PCE) extraction. Technical report, September 1, 1991--November 30, 1991

    SciTech Connect

    Chou, M.I.M.

    1991-12-31

    A pre-combustion coal desulfurization process at 120{degree}C using perchloroethylene (PCE) to remove up to 70% of the organic sulfur has been developed by the Midwest Ore Processing Co. (MWOPC). However, this process has not yet proven to be as successful with Illinois coals as it has for Ohio and Indiana coals. The organic sulfur removal has been achieved only with highly oxidized Illinois coals containing high sulfatic sulfur. A logical explanation for this observation is vital to successful process optimization for the use of Illinois coals. In addition, the high levels of organic sulfur removals observed by the MWOPC may be due to certain errors involved in the ASTM data interpretation; this needs verification. For example, elemental sulfur extracted by the PCE may be derived from pyrite oxidation during coal pre-oxidation, but it may be interpreted as organic sulfur removed by the PCE using ASTM analysis. The goals of this research are: (1) to independently confirm and possibly to improve the organic sulfur removal from Illinois coals with the PCE desulfurization process reported by the MWOPC, (2) to verify the forms-of-sulfur determination using the ASTM method for the PCE process evaluation, and (3) to determine the suitability of Illinois coals for use in the PCE desulfurization process. This project involves the Illinois State Geological Survey (ISGS), Eastern Illinois University (EIU), the University of Illinois-Urbana/Champaign (UI-UC), and the University of Kentucky, Lexington (UK). This is the first year of a two-year project.

  7. Foldable and High Sulfur Loading 3D Carbon Electrode for High-performance Li-S Battery Application

    PubMed Central

    He, Na; Zhong, Lei; Xiao, Min; Wang, Shuanjin; Han, Dongmei; Meng, Yuezhong

    2016-01-01

    Sulfur is a promising cathode material with a high theoretical capacity of 1672 mAh g−1, however, the practical energy density of Li-S battery is far away from such promising due to its low active material utilization and low sulfur loading. Moreover, the challenges of the low electrical conductivity of sulfur and the high solubility of polysulfide intermediates still hinder its practical application. Here, we report a kind of free-standing and foldable cathodes consisting of 3D activated carbon fiber matrix and sulfur cathode. The 3D activated carbon fiber matrix (ACFC) has continuous conductive framework and sufficient internal space to provide a long-distance and continuous high-speed electron pathway. It also gives a very larger internal space and tortuous cathode region to ACFC accommodate a highly sulfur loading and keeps polysulfide within the cathode. The unique structured 3D foldable sulfur cathode using a foldable ACFC as matrix delivers a reversible capacity of about 979 mAh g−1 at 0.2C, a capacity retention of 98% after 100 cycles, and 0.02% capacity attenuation per cycle. Even at an areal capacity of 6 mAh cm−2, which is 2 times higher than the values of Li-ion battery, it still maintains an excellent rate capability and cycling performance. PMID:27677602

  8. Foldable and High Sulfur Loading 3D Carbon Electrode for High-performance Li-S Battery Application

    NASA Astrophysics Data System (ADS)

    He, Na; Zhong, Lei; Xiao, Min; Wang, Shuanjin; Han, Dongmei; Meng, Yuezhong

    2016-09-01

    Sulfur is a promising cathode material with a high theoretical capacity of 1672 mAh g-1, however, the practical energy density of Li-S battery is far away from such promising due to its low active material utilization and low sulfur loading. Moreover, the challenges of the low electrical conductivity of sulfur and the high solubility of polysulfide intermediates still hinder its practical application. Here, we report a kind of free-standing and foldable cathodes consisting of 3D activated carbon fiber matrix and sulfur cathode. The 3D activated carbon fiber matrix (ACFC) has continuous conductive framework and sufficient internal space to provide a long-distance and continuous high-speed electron pathway. It also gives a very larger internal space and tortuous cathode region to ACFC accommodate a highly sulfur loading and keeps polysulfide within the cathode. The unique structured 3D foldable sulfur cathode using a foldable ACFC as matrix delivers a reversible capacity of about 979 mAh g-1 at 0.2C, a capacity retention of 98% after 100 cycles, and 0.02% capacity attenuation per cycle. Even at an areal capacity of 6 mAh cm-2, which is 2 times higher than the values of Li-ion battery, it still maintains an excellent rate capability and cycling performance.

  9. Foldable and High Sulfur Loading 3D Carbon Electrode for High-performance Li-S Battery Application.

    PubMed

    He, Na; Zhong, Lei; Xiao, Min; Wang, Shuanjin; Han, Dongmei; Meng, Yuezhong

    2016-09-28

    Sulfur is a promising cathode material with a high theoretical capacity of 1672 mAh g(-1), however, the practical energy density of Li-S battery is far away from such promising due to its low active material utilization and low sulfur loading. Moreover, the challenges of the low electrical conductivity of sulfur and the high solubility of polysulfide intermediates still hinder its practical application. Here, we report a kind of free-standing and foldable cathodes consisting of 3D activated carbon fiber matrix and sulfur cathode. The 3D activated carbon fiber matrix (ACFC) has continuous conductive framework and sufficient internal space to provide a long-distance and continuous high-speed electron pathway. It also gives a very larger internal space and tortuous cathode region to ACFC accommodate a highly sulfur loading and keeps polysulfide within the cathode. The unique structured 3D foldable sulfur cathode using a foldable ACFC as matrix delivers a reversible capacity of about 979 mAh g(-1) at 0.2C, a capacity retention of 98% after 100 cycles, and 0.02% capacity attenuation per cycle. Even at an areal capacity of 6 mAh cm(-2), which is 2 times higher than the values of Li-ion battery, it still maintains an excellent rate capability and cycling performance.

  10. Synthesis of three-dimensionally interconnected sulfur-rich polymers for cathode materials of high-rate lithium–sulfur batteries

    PubMed Central

    Kim, Hoon; Lee, Joungphil; Ahn, Hyungmin; Kim, Onnuri; Park, Moon Jeong

    2015-01-01

    Elemental sulfur is one of the most attractive cathode active materials in lithium batteries because of its high theoretical specific capacity. Despite the positive aspect, lithium–sulfur batteries have suffered from severe capacity fading and limited rate capability. Here we report facile large-scale synthesis of a class of organosulfur compounds that could open a new chapter in designing cathode materials to advance lithium–sulfur battery technologies. Porous trithiocyanuric acid crystals are synthesized for use as a soft template, where the ring-opening polymerization of elemental sulfur takes place along the thiol surfaces to create three-dimensionally interconnected sulfur-rich phases. Our lithium–sulfur cells display discharge capacity of 945 mAh g−1 after 100 cycles at 0.2 C with high-capacity retention of 92%, as well as lifetimes of 450 cycles. Particularly, the organized amine groups in the crystals increase Li+-ion transfer rate, affording a rate performance of 1210, mAh g−1 at 0.1 C and 730 mAh g−1 at 5 C. PMID:26065407

  11. Synthesis of three-dimensionally interconnected sulfur-rich polymers for cathode materials of high-rate lithium-sulfur batteries.

    PubMed

    Kim, Hoon; Lee, Joungphil; Ahn, Hyungmin; Kim, Onnuri; Park, Moon Jeong

    2015-06-12

    Elemental sulfur is one of the most attractive cathode active materials in lithium batteries because of its high theoretical specific capacity. Despite the positive aspect, lithium-sulfur batteries have suffered from severe capacity fading and limited rate capability. Here we report facile large-scale synthesis of a class of organosulfur compounds that could open a new chapter in designing cathode materials to advance lithium-sulfur battery technologies. Porous trithiocyanuric acid crystals are synthesized for use as a soft template, where the ring-opening polymerization of elemental sulfur takes place along the thiol surfaces to create three-dimensionally interconnected sulfur-rich phases. Our lithium-sulfur cells display discharge capacity of 945 mAh g(-1) after 100 cycles at 0.2 C with high-capacity retention of 92%, as well as lifetimes of 450 cycles. Particularly, the organized amine groups in the crystals increase Li(+)-ion transfer rate, affording a rate performance of 1210, mAh g(-1) at 0.1 C and 730 mAh g(-1) at 5 C.

  12. Synthesis of three-dimensionally interconnected sulfur-rich polymers for cathode materials of high-rate lithium-sulfur batteries

    NASA Astrophysics Data System (ADS)

    Kim, Hoon; Lee, Joungphil; Ahn, Hyungmin; Kim, Onnuri; Park, Moon Jeong

    2015-06-01

    Elemental sulfur is one of the most attractive cathode active materials in lithium batteries because of its high theoretical specific capacity. Despite the positive aspect, lithium-sulfur batteries have suffered from severe capacity fading and limited rate capability. Here we report facile large-scale synthesis of a class of organosulfur compounds that could open a new chapter in designing cathode materials to advance lithium-sulfur battery technologies. Porous trithiocyanuric acid crystals are synthesized for use as a soft template, where the ring-opening polymerization of elemental sulfur takes place along the thiol surfaces to create three-dimensionally interconnected sulfur-rich phases. Our lithium-sulfur cells display discharge capacity of 945 mAh g-1 after 100 cycles at 0.2 C with high-capacity retention of 92%, as well as lifetimes of 450 cycles. Particularly, the organized amine groups in the crystals increase Li+-ion transfer rate, affording a rate performance of 1210, mAh g-1 at 0.1 C and 730 mAh g-1 at 5 C.

  13. A high-density graphene-sulfur assembly: a promising cathode for compact Li-S batteries

    NASA Astrophysics Data System (ADS)

    Zhang, Chen; Liu, Dong-Hai; Lv, Wei; Wang, Da-Wei; Wei, Wei; Zhou, Guang-Min; Wang, Shaogang; Li, Feng; Li, Bao-Hua; Kang, Feiyu; Yang, Quan-Hong

    2015-03-01

    This work reports a high-density graphene/sulfur assembly for compact Li-S batteries with high volumetric capacity, which retains good structural stability and conductivity. This dense assembly was prepared by a reduction-triggered self-assembly of graphene oxide with simultaneous deposition of sulfur, followed by unique evaporation-induced spatial volume shrinkage. This assembly has an ultrahigh density, delivering an unprecedented volumetric capacity that is much higher than common carbon/sulfur cathodes. In particular, the unique spatial confinement derived from the shrinkage of the graphene/sulfur assembly is favorable for stabilizing sulfur cathodes.This work reports a high-density graphene/sulfur assembly for compact Li-S batteries with high volumetric capacity, which retains good structural stability and conductivity. This dense assembly was prepared by a reduction-triggered self-assembly of graphene oxide with simultaneous deposition of sulfur, followed by unique evaporation-induced spatial volume shrinkage. This assembly has an ultrahigh density, delivering an unprecedented volumetric capacity that is much higher than common carbon/sulfur cathodes. In particular, the unique spatial confinement derived from the shrinkage of the graphene/sulfur assembly is favorable for stabilizing sulfur cathodes. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr06863g

  14. High temperature superconductivity in sulfur and selenium hydrides at high pressure

    NASA Astrophysics Data System (ADS)

    Flores-Livas, José A.; Sanna, Antonio; Gross, E. K. U.

    2016-03-01

    Due to its low atomic mass, hydrogen is the most promising element to search for high-temperature phononic superconductors. However, metallic phases of hydrogen are only expected at extreme pressures (400 GPa or higher). The measurement of the record superconducting critical temperature of 203 K in a hydrogen-sulfur compound at 160 GPa of pressure [A.P. Drozdov, M.I. Eremets, I.A. Troyan, arXiv:1412.0460; [cond-mat.supr-con] (2014); A.P. Drozdov, M.I. Eremets, I.A. Troyan, V. Ksenofontov, S.I. Shylin, Nature 525, 73 (2015)], shows that metallization of hydrogen can be reached at significantly lower pressure by inserting it in the matrix of other elements. In this work we investigate the phase diagram and the superconducting properties of the H-S systems by means of minima hopping method for structure prediction and density functional theory for superconductors. We also show that Se-H has a similar phase diagram as its sulfur counterpart as well as high superconducting critical temperature. We predict H3Se to exceed 120 K superconductivity at 100 GPa. We show that both H3Se and H3S, due to the critical temperature and peculiar electronic structure, present rather unusual superconducting properties. Supplementary material in the form of one pdf file available from the Journal web page at: http://dx.doi.org/10.1140/epjb/e2016-70020-0

  15. Mineral trioxide aggregate: part 2 - a review of the material aspects.

    PubMed

    Malhotra, Neeraj; Agarwal, Antara; Mala, Kundabala

    2013-03-01

    The purpose of this two-part series is to review the composition, properties, and products of mineral trioxide aggregate (MTA) materials. PubMed and MedLine electronic databases were used to identify scientific papers from January 1991 to May 2010. Based on the selected inclusion criteria, citations were referenced from the scientific peer-reviewed dental literature. Mineral trioxide aggregate is a refined form of the parent compound, Portland cement (PC), and demonstrates a strong biocompatibility due to the high pH level and the material's ability to form hydroxyapatite. Mineral trioxide aggregate materials provide better microleakage protection than traditional endodontic materials as observed in findings from dye-leakage, fluid-filtration, protein-leakage, and bacterial penetration-leakage studies and has been recognized as a bioactive material. Various MTA commercial products are available, including gray mineral trioxide aggregate (GMTA), white mineral trioxide aggregate (WMTA), and mineral trioxide aggregate-Angelus (AMTA). Although these materials are indicated for various dental uses and applications, long-term in-vivo clinical studies are needed. Part 1 of this article highlighted and discussed the composition and characteristics of the material. Part 2 provides an overview of commercially available MTA materials.

  16. Extraction, separation and analysis of high sulfur coal

    SciTech Connect

    Olesik, S.V.

    1990-04-02

    In summary, significant bond cleavage was found only for thiophenol under the supercritical conditions studied. Less than 5% yield was found for the observed reaction products for all the other organosulfur compounds. The hydrogen sulfur bond in thiophenol is clearly the weakest of those studied and therefore it is the easiest to rupture. Also a general trend was observed the solvolysis reaction products such as ethylthiobenzene were the products initially formed at lower temperatures. But with higher temperatures the reaction product were those typically produced from the bimolecular association of free-radicals, such as phenylsulfide for the thiophenol sample. This type of reaction would be expected in pyrolysis reactions. Bimolecular reactions between organosulfur compounds would not be expected when the reaction is occurring at the surface of the solid coal matrix. The probability of the extracted organosulfur radicals having such bimolecular reactions is quite low. However, the reactions that are observed from the interaction of supercritical ethanol and the model coal compounds are not ones that show obvious indications of desulfurization of the compound.

  17. Experimental study of the combined calcination and hydrodesulfurization of high-sulfur green petroleum coke

    NASA Astrophysics Data System (ADS)

    Kilic, Saliha Meltem

    The primary production of aluminum is done by means of the Hall-Heroult process where large amounts of carbon anodes are required and consumed. The quality of carbon anodes used in electrolysis is one of the most important parameters affecting the production of primary aluminum. The anode quality widely depends on the raw materials, one of which is the petroleum coke. Green petroleum coke is produced from the heavy residual fractions of petroleum. Petroleum cokes produced from sour crude oil sources contain high quantity of sulfur. A certain level of sulfur is needed to reduce the anode reactivities; however, the demand for anode-grade coke with acceptable sulfur content is increasing faster than the available supply. High sulfur levels in carbon anodes would have an adverse effect on environment; hence, the desulfurization of high sulfur green petroleum cokes is necessary. There are different ways of desulfurizing green petroleum cokes: solvent extraction, thermal desulfurization, and hydrodesulfurization. Coke produced by solvent extraction is prone to contamination. The thermal approach requires greater energy consumption and causes an increase in coke porosity. The global objective of this master project is to find an alternative solution for desulfurization that will produce quality calcined coke with minimum impact on environment. Hydrodesulfurization seems to be a viable option and was investigated in this study. Water was used for the hydrodesulfurization of commercially available high sulfur green petroleum coke. Different experimental systems were tried during the hydrodesulfurization experiments. A systematic approach was used to investigate the influence of hydrodesulfurization parameters including water injection temperature, duration, and water flow rate as well as coke particle size on the hydrodesulfurization of green petroleum coke. In addition to hydrodesulfurization, a number of thermal desulfurization experiments were carried out with the same

  18. An experimental study on desulfurization of high-sulfur coal slime with free jet flotation column

    SciTech Connect

    Xie Hua; Huang Bo; Xia Qing

    1998-12-31

    A free jet flotation column gives good selectivity and high separation efficiency in treating fine and ultra-fine coal. This paper reports test results of coal desulfurization with a free jet flotation column. Test results showed that when the coal sample from Zhong Liang Shan was processed its pyritic sulfur content was reduced from 3.08% to 0.84%, with 72.22% recovery of combustible matter in clean coal. The concept of Desulfurization Efficiency Index E(ds) for a comprehensive evaluation of desulfurization process is proposed, which is defined as the product of the ratio of sulfur content reduction and the recovery of combustible matters in clean coal.

  19. High-resolution sulfur isotopes in ice cores identify large stratospheric volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Burke, Andrea; Sigl, Michael; Adkins, Jess; Paris, Guillaume; McConnell, Joe

    2016-04-01

    The record of the volcanic forcing of climate over the past 2500 years is reconstructed primarily from sulfate concentrations in ice cores. Of particular interest are stratospheric eruptions, as these afford sulfate aerosols the longest residence time and largest dispersion in the atmosphere, and thus the greatest impact on radiative forcing. Identification of stratospheric eruptions currently relies on the successful matching of the same volcanic sulphate peak in ice cores from both the Northern and Southern hemispheres (a "bipolar event"). These are interpreted to reflect the global distribution of sulfur aerosols by the stratospheric winds. Despite its recent success, this method relies on precise and accurate dating of ice cores, in order to distinguish between a true 'bipolar event' and two separate eruptions that occurred in close temporal succession. Sulfur isotopes can been used to distinguish between these two scenarios since stratospheric sulfur aerosols are exposed to UV radiation which imparts a mass independent fractionation (Baroni et al., 2007). Mass independent fractionation of sulfate in ice cores thus offers a novel method of fingerprinting stratospheric eruptions, and thus refining the historic record of explosive volcanism and its forcing of climate. Here we present new high-resolution (sub-annual) sulfur isotope data from the Tunu Ice core in Greenland over seven eruptions. Sulfur isotopes were measured by MC-ICP-MS, which substantially reduces sample size requirements and allows high temporal resolution from a single ice core. We demonstrate the efficacy of the method on recent, well-known eruptions (including Pinatubo and Katmai/Novarupta), and then apply it to unidentified sulfate peaks, allowing us to identify new stratospheric eruptions. Baroni, M., Thiemens, M. H., Delmas, R. J., & Savarino, J. (2007). Mass-independent sulfur isotopic compositions in stratospheric volcanic eruptions. Science, 315(5808), 84-87. http://doi.org/10

  20. Sulfur Concentration of High-FeO* Basalts at Sulfide Saturation at High Pressures and Temperatures - Implications for Deep Sulfur Cycle on Mars (Invited)

    NASA Astrophysics Data System (ADS)

    Dasgupta, R.; Ding, S.

    2013-12-01

    One of the chief influences of magma in the mantles terrestrial planets is its role in outgassing and ingassing of key volatiles and thus affecting planetary dynamics and climate over long timescales. For Mars, magmatic release of greenhouse gases has been argued to be a major factor in creating warm ancient climate. However, the responsible magmatic gas has not been unequivocally identified. SO2 or H2S could have been the main greenhouse gases, yet the magmatic outflux of S from the martian mantle is poorly constrained. Righter et al. [1] showed that the use of sulfur content at sulfide saturation (SCSS) models based on low-FeO*, high-alumina terrestrial basalts to martian basalts leads to significant error. However, experiments on high-FeO* basalts remain limited to ≤0.8 GPa [1], although the onset of melting in the martian mantle may take place at 250-400 km depth (3-5 GPa) [2]. To constrain SCSS of martian magmas at mantle conditions, we simulated basalt-sulfide melt equilibria using two synthesized meteorite compositions, i.e., Yamato980459 (FeO* ˜17 wt.%; Al2O3 ˜6 wt.%) and NWA2990 (FeO* ˜16 wt.%; Al2O3 ˜9 wt.%) in both anhydrous and hydrous conditions at 1-3 GPa and 1500-1700 °C. Experiments were conducted in graphite capsules, using an end-loaded piston cylinder device. Sulfur contents of sulfide melt-saturated experimental quenched basalts were determined using electron microprobe. Our experimental results show that SCSS decreases with increasing pressure and increases with increasing temperature and melt hydration. Based on our experimental SCSS and those from previous low-pressure experiments on high-FeO* martian basalts [2], we developed a new parameterization to predict martian basalt SCSS as a function of depth, temperature, and melt composition. Our model suggests that at the conditions of last equilibration with the sulfide-saturated mantle [2], martian basalts may contain as high as 3500-4700 ppm S and thus S-rich gases might have caused the

  1. Elemental sulfur-producing high-temperature fuel gas desulfurization process

    SciTech Connect

    Anderson, G.L.; Garrigan, P.C.; Berry, F.O.

    1980-01-01

    Preliminary studies have shown that certain materials when added to air-regenerable, high-temperature, fuel gas desulfurization sorbents, such as iron oxide or zinc oxide, significantly increase elemental sulfur formation during regeneration. Although the full range of conditions under which these materials can be applied remains to be determined, successful applications could eliminate a costly SO/sub 2/ reduction step.

  2. High-Southern Latitudes Sulfur Cycle in an Atmospheric General Circulation Model

    NASA Astrophysics Data System (ADS)

    Cosme, E.; Genthon, C.; Martinerie, P.; Boucher, O.; Pham, M.

    2002-05-01

    This modeling study (Cosme et al., Sulfur cycle in the high southern latitudes in the LMD-ZT General Circulation Model, submitted to JGR) was motivated by the recent publication of annual time-scale records of dimethylsulfide (DMS) and dimethylsulfoxide (DMSO) in Antarctica, completing the available series of sulfate and methanesulfonic acid (MSA). Sulfur chemistry has been incorporated in the Laboratoire de Météorologie Dynamique Atmospheric General Circulation Model (AGCM), LMD-ZT, with high resolution and improved physics in the high-southern latitudes. The model predicts the concentration of 6 major sulfur species through emissions, transport, wet and dry deposition and chemistry in both gaseous and aqueous phases. Model results are broadly realistic when compared with measurements in air and snow or ice, and to results of other modeling studies, at high- and mid- southern latitudes. Although not corrected in this work, defects are identified and discussed: Atmospheric MSA concentrations are underestimated and DMSO concentrations are overestimated in summer, reflecting the lack of a DMSO sink leading to MSA; the deposition scheme used in the model may not be adapted to polar regions; DMS concentrations are underestimated in winter, and the model does not adequately reproduces interannual variability. Oceanic DMS sources appear deciding for the description of the sulfur cycle in these regions. The model suggests that ground atmospheric DMS concentrations are higher in winter than in summer, in a large part of central Antarctica. In the high-southern latitudes, high loads of DMS and DMSO are found and the main chemical sink of sulfur dioxide (SO2) is aqueous oxidation by ozone (O3), whereas oxidation by hydrogen peroxide (H2O2) dominates at the global scale.

  3. The sulfur cycle at high-southern latitudes in the LMD-ZT General Circulation Model

    NASA Astrophysics Data System (ADS)

    Cosme, E.; Genthon, C.; Martinerie, P.; Boucher, O.; Pham, M.

    2002-12-01

    This modeling study was motivated by the recent publication of year-round records of dimethylsulfide (DMS) and dimethylsulfoxide (DMSO) in Antarctica, completing the available series of sulfate and methanesulfonic acid (MSA). Sulfur chemistry has been incorporated in the Laboratoire de Météorologie Dynamique-Zoom Tracers (LMD-ZT) Atmospheric General Circulation Model (AGCM), with high-resolution and improved physics at high-southern latitudes. The model predicts the concentration of six major sulfur species through emissions, transport, wet and dry deposition, and chemistry in both gas and aqueous phases. Model results are broadly realistic when compared with measurements in air and snow or ice, as well as to results of other modeling studies, at high- and middle-southern latitudes. Atmospheric MSA concentrations are underestimated and DMSO concentrations are overestimated in summer, reflecting the lack of a DMSO heterogeneous sink leading to MSA. Experiments with various recently published estimates of the rate of this sink are reported. Although not corrected in this work, other defects are identified and discussed: DMS concentrations are underestimated in winter, MSA and non-sea-salt (nss) sulfate concentrations may be underestimated at the South Pole, the deposition scheme used in the model may not be adapted to polar regions, and the model does not adequately reproduces interannual variability. Oceanic DMS sources have a major contribution to the variability of sulfur in these regions. The model results suggest that in a large part of central Antarctica ground-level atmospheric DMS concentrations are larger in winter than in summer. At high-southern latitudes, high loads of DMS and DMSO are found and the main chemical sink of sulfur dioxide (SO2) is aqueous oxidation by ozone (O3), whereas oxidation by hydrogen peroxide (H2O2) dominates at the global scale. A comprehensive modeled sulfur budget of Antarctica is provided.

  4. Determination of sulfur in food by high resolution continuum source flame molecular absorption spectrometry

    NASA Astrophysics Data System (ADS)

    Zambrzycka, Elżbieta; Godlewska-Żyłkiewicz, Beata

    2014-11-01

    In the present work, a fast, simple and sensitive analytical method for determination of sulfur in food and beverages by high resolution continuum source flame molecular absorption spectrometry was developed. The determination was performed via molecular absorption of carbon monosulfide, CS. Different CS rotational lines (257.959 nm, 258.033 nm, 258.055 nm), number of pixels and types of standard solution of sulfur, namely: sulfuric acid, sodium sulfate, ammonium sulfate, sodium sulfite, sodium sulfide, DL-cysteine, and L-cystine, were studied in terms of sensitivity, repeatability of results as well as limit of detection and limit of quantification. The best results were obtained for measurements of absorption of the CS molecule at 258.055 nm at the wavelength range covering 3 pixels and DL-cysteine in 0.2 mol L- 1 HNO3 solution as a calibration standard. Under optimized conditions the limit of detection and the limit of quantification achieved for sulfur were 10.9 mg L- 1 and 36.4 mg L- 1, respectively. The repeatability of the results expressed as relative standard deviation was typically < 5%. The accuracy of the method was tested by analysis of digested biological certified reference materials (soya bean flour, corn flour and herbs) and recovery experiment for beverage samples with added known amount of sulfur standard. The recovery of analyte from such samples was in the range of 93-105% with the repeatability in the range of 4.1-5.0%. The developed method was applied for the determination of sulfur in milk (194 ± 10 mg kg- 1), egg white (2188 ± 29 mg kg- 1), mineral water (31.0 ± 0.9 mg L- 1), white wine (260 ± 4 mg L- 1) and red wine (82 ± 2 mg L- 1), as well as in sample rich in ions, such as bitter mineral water (6900 ± 100 mg L- 1).

  5. Co-firing high sulfur coal with refuse derived fuels. Final report

    SciTech Connect

    Pan, W.P.; Riley, J.T.; Lloyd, W.G.

    1997-11-30

    This project was designed to evaluate the combustion performance of and emissions from a fluidized bed combustor during the combustion of mixtures of high sulfur and/or high chlorine coals and municipal solid waste (MSW). The project included four major tasks, which were as follows: (1) Selection, acquisition, and characterization of raw materials for fuels and the determination of combustion profiles of combination fuels using thermal analytical techniques; (2) Studies of the mechanisms for the formation of chlorinated organics during the combustion of MSW using a tube furnace; (3) Investigation of the effect of sulfur species on the formation of chlorinated organics; and (4) Examination of the combustion performance of combination fuels in a laboratory scale fluidized bed combustor. Several kinds of coals and the major combustible components of the MSW, including PVC, newspaper, and cellulose were tested in this project. Coals with a wide range of sulfur and chlorine contents were used. TGA/MS/FTIR analyses were performed on the raw materials and their blends. The possible mechanism for the formation of chlorinated organics during combustion was investigated by conducting a series of experiments in a tube furnace. The effect of sulfur dioxide on the formation of molecular chlorine during combustion processes was examined in this study.

  6. Advanced sulfur control concepts in hot-gas desulfurization technology: Phase 1, Feasibility of the direct production of elemental sulfur during the regeneration of high temperature desulfurization sorbents

    SciTech Connect

    Lopez, A.; White, J.; Groves, F.R.; Harrison, D.P.

    1994-10-01

    This topical report de-scribes the results of Phase 1 research performed during the first six months of a three-year contract to study the feasibility of the direct production of elemental sulfur during the regeneration of high temperature desulfurization sorbents. Much effort has gone into the development of a high-temperature meal oxide sorbent process for removal of H{sub 2}S from the coal gas. A number of sorbents based upon metals such as zinc, iron, manganese and others have been studied. In order for high temperature desulfurization to be economical it is necessary that the sorbents be regenerated to permit multicycle operation. Current methods of sorbent regeneration involve oxidation of the metal sulfide to reform the metal oxide and free the sulfur as SO{sub 2}. An alternate regeneration process in which the sulfur is liberated in elemental form is preferable. The overall objective of the current research is to study simpler and economically superior processing of known sorbents capable of producing elemental sulfur during regeneration. This topical report summarizes the first steps of this effort. A literature search has been completed to identify possible regeneration concepts and to collect relevant thermodynamic, kinetic, and process data. Three concepts involving reaction with SO{sub 2}, partial oxidation using an O{sub 2} {minus} H{sub 2}O mixture, and steam regeneration have been identified. The first two concepts result in the direct production of elemental sulfur while H{sub 2}S is the product of steam regeneration. This concept is of potential interest, however, since existing Claus technology can be used to convert H{sub 2}S to elemental sulfur. Following the literature search, a thermodynamic analysis, based upon free-energy minimization was carried out to evaluate candidate sorbents for possible use with the three regeneration concepts.

  7. Destruction of a high sulfur pitch in an industrial scale fluidized bed combustor

    SciTech Connect

    North, B.; Eleftheriades, C.; Engelbrecht, A.; Rutherford-Jones, J.

    1999-07-01

    Sasol approached the CSIR's division of Materials Science and Technology (CSIR Mattek) for an environmentally acceptable solution to their steadily increasing stockpiles of a high sulfur pitch. Conventional incineration of the pitch would result in unacceptably high levels of sulfur dioxide emission to the atmosphere. In addition to the pitch, Sasol indicated a need to dispose of a waste water stream contaminated with organic compounds. After some initial development work CSIR Mattek, in conjunction with its licensee IMS Process Plant, presented a design for a multipurpose bubbling fluidized bed incineration plant that completely destroys the pitch and effluent water while capturing a minimum of 85% of the incoming sulfur in the pitch by limestone injection. The plant design caters for the variable consistency of both the pitch and the organic waste water, which can contain from 0 to 10% organics. The design also allows for potential future treatment of contaminated soils. In addition to the environment benefit of the reduction of sulfur dioxide emissions, the plant also makes use of the hot combustion gases to raise 20 t/hr of saturated steam at 20 bar via an external waste heat boiler. This represents a valuable commodity for the business unit responsible for the waste incineration and makes the Sasol plant a more energy efficient entity. It also represents a net reduction in CO{sub 2} emissions from Sasol. The high sulfur pitch incineration plant was commissioned in Sasolburg by a team of engineers from CSIR Mattek, IMS Process Plant and Sasol during December 1996 and January/February 1997. The plant has performed extremely well and it has complied with the environmental emission requirements as set out by the Department of Environmental Affairs and Tourism.

  8. Primary structures of high potential, four-iron-sulfur ferredoxins from the purple sulfur photosynthetic bacteria, Thiocapsa roseopersicina and Chromatium gracile

    SciTech Connect

    Tedro, S.M.; Meyer, T.E.; Bartsch, R.G.; Kamen, M.D.

    1981-01-25

    The amino acid sequences of high potential iron-sulfur proteins (HiPIP) from the purple sulfur photosynthetic bacteria Thiocapsa roseopersicina and Chromatium gracile were determined by alignment of tryptic peptides with the amino acid sequence of HiPIP from the closely related bacterium Chromatium vinosum, strain D. The two new sequences exhibit about 80% similarity to that of C. vinosum, but only an average of 33% similarity to the other known HiPIP species. Comparison of the three closely related sequences prompted a reinvestigation of the C. vinosum sequence, which resulted in three corrections, all involving changes of asparagine or aspartic acid to their respective acid or amide.

  9. Synergistic Ultrathin Functional Polymer-Coated Carbon Nanotube Interlayer for High Performance Lithium-Sulfur Batteries.

    PubMed

    Kim, Joo Hyun; Seo, Jihoon; Choi, Junghyun; Shin, Donghyeok; Carter, Marcus; Jeon, Yeryung; Wang, Chengwei; Hu, Liangbing; Paik, Ungyu

    2016-08-10

    Lithium-sulfur (Li-S) batteries have been intensively investigated as a next-generation rechargeable battery due to their high energy density of 2600 W·h kg(-1) and low cost. However, the systemic issues of Li-S batteries, such as the polysulfide shuttling effect and low Coulombic efficiency, hinder the practical use in commercial rechargeable batteries. The introduction of a conductive interlayer between the sulfur cathode and separator is a promising approach that has shown the dramatic improvements in Li-S batteries. The previous interlayer work mainly focused on the physical confinement of polysulfides within the cathode part, without considering the further entrapment of the dissolved polysulfides. Here, we designed an ultrathin poly(acrylic acid) coated single-walled carbon nanotube (PAA-SWNT) film as a synergic functional interlayer to address the issues mentioned above. The designed interlayer not only lowers the charge transfer resistance by the support of the upper current collector but also localizes the dissolved polysulfides within the cathode part by the aid of a physical blocking and chemical bonding. With the synergic combination of PAA and SWNT, the sulfur cathode with a PAA-SWNT interlayer maintained higher capacity retention over 200 cycles and achieved better rate retention than the sulfur cathode with a SWNT interlayer. The proposed approach of combining a functional polymer and conductive support material can provide an optimiztic strategy to overcome the fundamental challenges underlying in Li-S batteries.

  10. Back-Transport of Sulfur Species in the High-Southern Latitudes

    NASA Astrophysics Data System (ADS)

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

    2002-05-01

    To interpret polar ice core records of sulfate and methanesulfonic acid (MSA), a good understanding of the processes involved in dimethylsulfide (DMS) oxidation is needed. In particular, the signification of changes in the MSA to non-sea-salt sulfate ratio remains unclear. In cold environment, DMS oxidation through the addition channel, partly leading to MSA, prevails over the abstraction channel that does not yield MSA. However, at several Antarctic stations, the MSA to non-sea-salt sulfate ratio is found higher in the summer (warmer) season than in winter. To improve the interpretation of the MSA to non-sea-salt sulfate ratio, we wish to locate the sources contributing to the sulfur species in Antarctica and to identify how they change with season. To do this, we use the Laboratoire de Météorologie Dynamique (CNRS, Paris, France) Atmospheric General Circulation Model with an imbedded sulfur chemistry module (Cosme et al., Sulfur cycle in the high southern latitudes in the LMD-ZT General Circulation Model, submitted to JGR). The climate / chemistry model is first run forward to archive climate and chemistry parameters which affect the sulfur species. These parameters are then used to run backward an adjoint of the model, thus providing an inverse history of transport and chemistry. We will first present the adjoint transport and chemistry equations. Then we will show and discuss preliminary results related to the interpretation of the MSA to non-sea-salt sulfate ratio in the Antarctic region.

  11. Back-Transport of Sulfur Species in the High-Southern Latitude

    NASA Astrophysics Data System (ADS)

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

    2003-04-01

    To interpret polar ice core records of sulfate and methanesulfonic acid (MSA), a good understanding of the processes involved in dimethylsulfide (DMS) oxidation is needed. In particular, the signification of changes in the MSA to non-sea-salt sulfate ratio remains unclear. In cold environment, DMS oxidation through the addition channel, partly leading to MSA, prevails over the abstraction channel that does not yield MSA. However, at several Antarctic stations, the MSA to non-sea-salt sulfate ratio is found higher in the summer (warmer) season than in winter. To improve the interpretation of the MSA to non-sea-salt sulfate ratio, we wish to locate the sources contributing to the sulfur species in Antarctica and to identify how they change with season. To do this, we use the Laboratoire de Météorologie Dynamique (CNRS, Paris, France) Atmospheric General Circulation Model with an imbedded sulfur chemistry module (Cosme et al., Sulfur cycle in the high southern latitudes in the LMD-ZT General Circulation Model, JGR 107). The climate /chemistry model is first run forward to archive climate and chemistry parameters which affect the sulfur species. These parameters are then used to run backward an adjoint of the model, thus providing an inverse history of transport and chemistry. We will first present the adjoint transport and chemistry equations. Then we will show and discuss preliminary results related to the interpretation of the MSA to non-sea-salt sulfate ratio in the Antarctic region.

  12. Lunar sulfur

    NASA Technical Reports Server (NTRS)

    Kuck, David L.

    1991-01-01

    Ideas introduced by Vaniman, Pettit and Heiken in their 1988 Uses of Lunar Sulfur are expanded. Particular attention is given to uses of SO2 as a mineral-dressing fluid. Also introduced is the concept of using sulfide-based concrete as an alternative to the sulfur-based concretes proposed by Leonard and Johnson. Sulfur is abundant in high-Ti mare basalts, which range from 0.16 to 0.27 pct. by weight. Terrestrial basalts with 0.15 pct. S are rare. For oxygen recovery, sulfur must be driven off with other volatiles from ilmenite concentrates, before reduction. Troilite (FeS) may be oxidized to magnetite (Fe3O4) and SO2 gas, by burning concentrates in oxygen within a magnetic field, to further oxidize ilmenite before regrinding the magnetic reconcentration. SO2 is liquid at -20 C, the mean temperature underground on the Moon, at a minimum of 0.6 atm pressure. By using liquid SO2 as a mineral dressing fluid, all the techniques of terrestrial mineral separation become available for lunar ores and concentrates. Combination of sulfur and iron in an exothermic reaction, to form iron sulfides, may be used to cement grains of other minerals into an anhydrous iron-sulfide concrete. A sulfur-iron-aggregate mixture may be heated to the ignition temperature of iron with sulfur to make a concrete shape. The best iron, sulfur, and aggregate ratios need to be experimentally established. The iron and sulfur will be by-products of oxygen production from lunar minerals.

  13. High rate lithium-sulfur battery enabled by sandwiched single ion conducting polymer electrolyte

    NASA Astrophysics Data System (ADS)

    Sun, Yubao; Li, Gai; Lai, Yuanchu; Zeng, Danli; Cheng, Hansong

    2016-02-01

    Lithium-sulfur batteries are highly promising for electric energy storage with high energy density, abundant resources and low cost. However, the battery technologies have often suffered from a short cycle life and poor rate stability arising from the well-known “polysulfide shuttle” effect. Here, we report a novel cell design by sandwiching a sp3 boron based single ion conducting polymer electrolyte film between two carbon films to fabricate a composite separator for lithium-sulfur batteries. The dense negative charges uniformly distributed in the electrolyte membrane inherently prohibit transport of polysulfide anions formed in the cathode inside the polymer matrix and effectively blocks polysulfide shuttling. A battery assembled with the composite separator exhibits a remarkably long cycle life at high charge/discharge rates.

  14. High rate lithium-sulfur battery enabled by sandwiched single ion conducting polymer electrolyte.

    PubMed

    Sun, Yubao; Li, Gai; Lai, Yuanchu; Zeng, Danli; Cheng, Hansong

    2016-02-22

    Lithium-sulfur batteries are highly promising for electric energy storage with high energy density, abundant resources and low cost. However, the battery technologies have often suffered from a short cycle life and poor rate stability arising from the well-known "polysulfide shuttle" effect. Here, we report a novel cell design by sandwiching a sp(3) boron based single ion conducting polymer electrolyte film between two carbon films to fabricate a composite separator for lithium-sulfur batteries. The dense negative charges uniformly distributed in the electrolyte membrane inherently prohibit transport of polysulfide anions formed in the cathode inside the polymer matrix and effectively blocks polysulfide shuttling. A battery assembled with the composite separator exhibits a remarkably long cycle life at high charge/discharge rates.

  15. High rate lithium-sulfur battery enabled by sandwiched single ion conducting polymer electrolyte

    PubMed Central

    Sun, Yubao; Li, Gai; Lai, Yuanchu; Zeng, Danli; Cheng, Hansong

    2016-01-01

    Lithium-sulfur batteries are highly promising for electric energy storage with high energy density, abundant resources and low cost. However, the battery technologies have often suffered from a short cycle life and poor rate stability arising from the well-known “polysulfide shuttle” effect. Here, we report a novel cell design by sandwiching a sp3 boron based single ion conducting polymer electrolyte film between two carbon films to fabricate a composite separator for lithium-sulfur batteries. The dense negative charges uniformly distributed in the electrolyte membrane inherently prohibit transport of polysulfide anions formed in the cathode inside the polymer matrix and effectively blocks polysulfide shuttling. A battery assembled with the composite separator exhibits a remarkably long cycle life at high charge/discharge rates. PMID:26898772

  16. Self-Assembly of Polyethylene Glycol-Grafted Carbon Nanotube/Sulfur Composite with Nest-like Structure for High-Performance Lithium-Sulfur Batteries.

    PubMed

    Li, Han; Sun, Liping; Wang, Gengchao

    2016-03-09

    The novel polyethylene glycol-grafted multiwalled carbon nanotube/sulfur (PEG-CNT/S) composite cathodes with nest-like structure are fabricated through a facile combination process of liquid phase deposition and self-assembly, which consist of the active material core of sulfur particle and the conductive shell of PEG-CNT network. The unique architecture not only provides a short and rapid charge transfer pathway to improve the reaction kinetics but also alleviates the volume expansion of sulfur during lithiation and minimizes the diffusion of intermediate polysulfides. Such an encouraging electrochemical environment ensures the excellent rate capability and high cycle stability. As a result, the as-prepared PEG-CNT/S composite with sulfur content of 75.9 wt % delivers an initial discharge capacity of 1191 and 897 mAh g(-1) after 200 cycles at 0.2 C with an average Coulombic efficiency of 99.5%. Even at a high rate of 2 C, an appreciable capacity of 723 mAh g(-1) can still be obtained.

  17. High-voltage electrical apparatus utilizing an insulating gas of sulfur hexafluoride and helium

    DOEpatents

    Wootton, Roy E.

    1980-01-01

    High-voltage electrical apparatus includes an outer housing at low potential, an inner electrode disposed within the outer housing at high potential with respect thereto, and support means for insulatably supporting the inner electrode within the outer housing. Conducting particles contaminate the interior of the outer housing, and an insulating gas electrically insulates the inner electrode from the outer housing even in the presence of the conducting particles. The insulating gas is comprised of sulfur hexafluoride at a partial pressure of from about 2.9 to about 3.4 atmospheres absolute, and helium at a partial pressure from about 1.1 to about 11.4 atmospheres absolute. The sulfur hexafluoride comprises between 20 and 65 volume percent of the insulating gas.

  18. Processes for preparing carbon fibers using gaseous sulfur trioxide

    SciTech Connect

    Barton, Bryan E.; Lysenko, Zenon; Bernius, Mark T.; Hukkanen, Eric J.

    2016-01-05

    Disclosed herein are processes for preparing carbonized polymers, such as carbon fibers, comprising: sulfonating a polymer with a sulfonating agent that comprises SO.sub.3 gas to form a sulfonated polymer; treating the sulfonated polymer with a heated solvent, wherein the temperature of said solvent is at least 95.degree. C.; and carbonizing the resulting product by heating it to a temperature of 500-3000.degree. C.

  19. Hybrid sulfur cycle operation for high-temperature gas-cooled reactors

    DOEpatents

    Gorensek, Maximilian B

    2015-02-17

    A hybrid sulfur (HyS) cycle process for the production of hydrogen is provided. The process uses a proton exchange membrane (PEM) SO.sub.2-depolarized electrolyzer (SDE) for the low-temperature, electrochemical reaction step and a bayonet reactor for the high-temperature decomposition step The process can be operated at lower temperature and pressure ranges while still providing an overall energy efficient cycle process.

  20. Biological Effects of Short, High-Level Exposure to Gases: Sulfur Dioxide.

    DTIC Science & Technology

    1980-05-01

    This project was one of four under the same contract; the others covered were ammonia, carbon monoxide, and the nitrogen oxides. I! V It. KEY WORDS...biologic responses to short, high-level exposures to four gases (ammonia, carbon monoxide, sulfur dioxide, and the nitrogen oxides) that may be...associated with certain Army weapons systems and troop field training activities . Thisreport analyzes and synthesizes the available literature on possible

  1. SnO2 as a high-efficiency polysulfide trap in lithium-sulfur batteries

    NASA Astrophysics Data System (ADS)

    Liu, Jing; Yuan, Lixia; Yuan, Kai; Li, Zhen; Hao, Zhangxiang; Xiang, Jingwei; Huang, Yunhui

    2016-07-01

    The ithium-sulfur battery stands as one of the most promising successors of traditional lithium-ion batteries due to its super high theoretical energy density, but practical application still suffers from the shuttle effect arising from soluble intermediate polysulfides. Here, we report SnO2 as a chemical adsorbent for polysulfides. As an interlayer between the cathode and separator, SnO2 gives better results to prevent the polysulfides from diffusing to the lithium anode than as a modifier of the carbon matrix directly. The lithium-sulfur battery with an SnO2 interlayer delivers an initial reversible capacity of 996 mA h g-1 and retains 832 mA h g-1 at the 100th discharge at 0.5 C, with a fading rate of only 0.19% per cycle. The improvements benefit from the quasi-open space provided by the interlayer configuration for the diffused sulfur species, which can largely relieve the loss of active substances caused by the volume effect during the lithiation/delithiation process.The ithium-sulfur battery stands as one of the most promising successors of traditional lithium-ion batteries due to its super high theoretical energy density, but practical application still suffers from the shuttle effect arising from soluble intermediate polysulfides. Here, we report SnO2 as a chemical adsorbent for polysulfides. As an interlayer between the cathode and separator, SnO2 gives better results to prevent the polysulfides from diffusing to the lithium anode than as a modifier of the carbon matrix directly. The lithium-sulfur battery with an SnO2 interlayer delivers an initial reversible capacity of 996 mA h g-1 and retains 832 mA h g-1 at the 100th discharge at 0.5 C, with a fading rate of only 0.19% per cycle. The improvements benefit from the quasi-open space provided by the interlayer configuration for the diffused sulfur species, which can largely relieve the loss of active substances caused by the volume effect during the lithiation/delithiation process. Electronic

  2. Well-dispersed sulfur anchored on interconnected polypyrrole nanofiber network as high performance cathode for lithium-sulfur batteries

    NASA Astrophysics Data System (ADS)

    Yin, Fuxing; Liu, Xinyi; Zhang, Yongguang; Zhao, Yan; Menbayeva, Almagul; Bakenov, Zhumabay; Wang, Xin

    2017-04-01

    Preparation of novel sulfur/polypyrrole (S/PPy) composite consisting well-dispersed sulfur particles anchored on interconnected PPy nanowire network was demonstrated. In such hybrid structure, the as-prepared PPy clearly displays a three-dimensionally cross-linked and hierarchical porous structure, which was utilized in the composite cathode as a conductive network trapping soluble polysulfide intermediates and enhancing the overall electrochemical performance of the system. Benefiting from this unique structure, the S/PPy composite demonstrated excellent cycling stability, resulting in a discharge capacity of 931 mAh g-1 at the second cycle and retained about 54% of this value over 100 cycles at 0.1 C. Furthermore, the S/PPy composite cathode exhibits a good rate capability with a discharge capacity of 584 mAh g-1 at 1 C.

  3. Origin of the critical temperature discontinuity in superconducting sulfur under high pressure

    NASA Astrophysics Data System (ADS)

    Monni, M.; Bernardini, F.; Sanna, A.; Profeta, G.; Massidda, S.

    2017-02-01

    Elemental sulfur shows a superconducting phase at high pressure (above 100 GPa), with critical temperatures that rise up to 20 K [Phys. Rev. B 65, 064504 (2002), 10.1103/PhysRevB.65.064504; Nature (London) 525, 73 (2015), 10.1038/nature14964] and presenting a jump at about 160 GPa, close to a structural phase transition to the β -Po phase. In this work we present a theoretical and fully ab initio characterization of sulfur based on superconducting density functional theory (SCDFT), focusing in the pressure range from 100 to 200 GPa. Calculations result in very good agreement with available experiments and point out that the origin of the critical temperature discontinuity is not related to the structural phase transition but induced by an electronic Lifshitz transition. This brings a strongly (interband) coupled electron pocket available for the superconducting condensation.

  4. Co-firing high sulfur coal with refuse derived fuels. Quarterly report, October - December 1996

    SciTech Connect

    Pan, W.-P.; Riley, J.T.; Lloyd, W.G.

    1996-12-01

    The objectives of this quarter of study on the co-firing of high sulfur coal with refuse derived fuels project were two-fold. First, the effect of S0{sub 2} on the formation of chlorine during combustion processes was examined. To simulate the conditions used in the AFBC system, experiments were conducted in a quartz tube in an electrically heated furnace. The principle analytical technique used for identification of the products from this study was GC/MS. The evolved gas was trapped by an absorbent and analyzed with a GC/MS system. The preliminary results indicate an inhibiting effect of S0{sub 2} on the Deacon Reaction. Secondly, information on the evolution of chlorine, sulfur and organic compounds from coals 95031 and 95011 were studied with the AFBC system. 2 figs., 1 tab.

  5. Determination of halogens and sulfur in high-purity polyimide by IC after digestion by MIC.

    PubMed

    Krzyzaniak, Sindy R; Santos, Rafael F; Dalla Nora, Flavia M; Cruz, Sandra M; Flores, Erico M M; Mello, Paola A

    2016-09-01

    In this work, a method for sample preparation of high-purity polyimide was proposed for halogens and sulfur determination by ion chromatography (IC) with conductivity detection and, alternatively, by inductively coupled plasma mass spectrometry (ICP-MS). A relatively high polyimide mass (600mg) was completely digested by microwave-induced combustion (MIC) using 20bar of O2 and 50mmolL(-1) NH4OH as absorbing solution. These conditions allowed final solutions with low carbon content (<10mgL(-1)) and suitable pH for analysis by both IC and ICP-MS. The accuracy was evaluated using a certified reference material of polymer for Cl, Br and S and spike recovery experiments for all analytes. No statistical difference (t-test, 95% of confidence level) was observed between the results obtained for Cl, Br and S by IC after MIC and the certified values. In addition, spike recoveries obtained for F, Cl, Br, I and S ranged from 94% to 101%. The proposed method was suitable for polyimide decomposition for further determination of halogens and sulfur by IC and by ICP-MS (Br and I only). Taking into account the lack of methods and the difficulty of bringing this material into solution, MIC can be considered as a suitable alternative for the decomposition of polyimide for routine quality control of halogens and sulfur using IC or ICP-MS.

  6. Producing bismuth trioxide and its application in fire assaying

    NASA Astrophysics Data System (ADS)

    Kelly, Zack; Ojebuoboh, Funsho

    2002-04-01

    Bismuth trioxide (Bi2O3) is the prevalent commercial oxide of bismuth. A precursor to the preparation of other compounds of bismuth, including the chemical reagents, bismuth trioxide has specialized uses in optical glass, flame-retardant paper, and, increasingly, in glaze formulations where it substitutes for lead oxides. In the last decade, bismuth trioxide has also become a key ingredient in flux formulations used by mineral analysts in fire assaying. The production of bismuth trioxide generally begins with the minor metal bismuth. This paper describes bismuth trioxide production and the properties and basis for its use in environmentally sound fire assaying.

  7. Sulfurization of α-MoO{sub 3} nanostructured thin film

    SciTech Connect

    Kumar, Prabhat; Singh, Megha; Sharma, Rabindar K. Reddy, G. B.

    2015-08-28

    In this report, the sulfurization of vertically aligned molybdenum trioxide (α- MoO{sub 3}) nanoflakes (NFs) with high aspect ratio (height/thickness >20) on the nickel coated glass substrates in a mixture of H{sub 2}S and argon gas at atmospheric pressure has been studied. The effect of sulfurization have been investigated to understand the basic reaction mechanism and the morphology, structural properties of grown nanoflakes. XPS and XRD indicate the formation of MoS{sub 2} along with the other intermediate phase such as MoO{sub 2} at temperature 200 °C. The surface morphology of samples have been studied systematically by using scanning electron microscope (SEM). The results demonstrate partial conversion of MoO{sub 3} NFs into MoS{sub 2} along with the change in the morphology of nanoflakes. All the observed results are well in consonance with each other.

  8. Strings of Porous Carbon Polyhedrons as Self-Standing Cathode Host for High-Energy-Density Lithium-Sulfur Batteries.

    PubMed

    Liu, Yazhi; Li, Gaoran; Fu, Jing; Chen, Zhongwei; Peng, Xinsheng

    2017-03-22

    Rational design of cathode hosts with high electrical conductivity and strong sulfur confinement is a great need for high-performance lithium-sulfur batteries. Herein, we report a self-standing, hybrid-nanostructured cathode host comprised of metal-organic framework (MOF)-derived porous carbon polyhedrons and carbon nanotubes (CNTs) for the significant improvement of both the electrode cyclability and energy density. The strong coupling of the intertwined CNTs and strung porous carbon polyhedrons as a binder-free thin film significantly enhances the long-range electronic conductivity and provides abundant active interfaces as well as robust electrode integrity for sulfur electrochemistry. Attributed to the synergistic combination of the CNTs and carbon polyhedrons, the obtained sulfur electrodes exhibit outstanding cyclability, an excellent high-rate response up to 10 C, and an ultra-high volumetric capacity of 960 Ah L(-1) .

  9. Prevention of formation of acid drainage from high-sulfur coal refuse by inhibition of iron- and sulfur-oxidizing microorganisms. I. Preliminary experiments in controlled shaken flasks.

    PubMed

    Dugan, P R

    1987-01-01

    Changes of pH and sulfate concentration in high-sulfur coal refuse slurries are used as measurements of microbial pyrite oxidation in the laboratory. Sodium lauryl sulfate (SLS), alkylbenzene sulfonate (ABS), benzoic acid (BZ) and combinations of SLS plus BZ and ABS plus BZ effectively inhibited formation of sulfate and acid when added in concentrations greater than 50 mg/L to inoculated 20 or 30% coal refuse slurries. Here 25 mg/L concentrations of SLS, ABS, and ABS + BZ stimulated acid production. Formic, hexanoic, oxalic, propionic, and pyruvic acids at 0.1% concentrations were also effective inhibitors. Four different lignin sulfonates were only slightly effective inhibitors at 0.1% concentrations. It was concluded that acid formation resulting from microbial oxidation in high-sulfur coal refuse can be inhibited.

  10. Sulfur-oxidizing chemolithotrophic proteobacteria dominate the microbiota in high arctic thermal springs on Svalbard.

    PubMed

    Reigstad, Laila Johanne; Jorgensen, Steffen Leth; Lauritzen, Stein-Erik; Schleper, Christa; Urich, Tim

    2011-09-01

    The thermal springs Trollosen and Fisosen, located on the High Arctic archipelago Svalbard, discharge saline groundwaters rich in hydrogen sulfide and ammonium through a thick layer of permafrost. Large amounts of biomass that consist of filamentous microorganisms containing sulfur granules, as analyzed with energy dispersive X-ray analysis, were found in the outflow. Prokaryotic 16S rRNA gene libraries and quantitative polymerase chain reaction (qPCR) analyses reported bacteria of the γ- and ɛ-proteobacterial classes as the dominant organisms in the filaments and the planktonic fractions, closely related to known chemolithoautotrophic sulfur oxidizers (Thiotrix and Sulfurovum). Archaea comprised ∼1% of the microbial community, with the majority of sequences affiliated with the Thaumarchaeota. Archaeal and bacterial genes coding for a subunit of the enzyme ammonia monooxygenase (amoA) were detected, as well as 16S rRNA genes of Nitrospira, all of which is indicative of potential complete nitrification in both springs. 16S rRNA sequences related to methanogens and methanotrophs were detected as well. This study provides evidence that the microbial communities in Trollosen and Fisosen are sustained by chemolithotrophy, mainly through the oxidation of reduced sulfur compounds, and that ammonium and methane might be minor, additional sources of energy and carbon.

  11. Bioconversion of High Concentrations of Hydrogen Sulfide to Elemental Sulfur in Airlift Bioreactor

    PubMed Central

    Abdel-Monaem Zytoon, Mohamed; Ahmad AlZahrani, Abdulraheem; Hamed Noweir, Madbuli; Ahmed El-Marakby, Fadia

    2014-01-01

    Several bioreactor systems are used for biological treatment of hydrogen sulfide. Among these, airlift bioreactors are promising for the bioconversion of hydrogen sulfide into elemental sulfur. The performance of airlift bioreactors is not adequately understood, particularly when directly fed with hydrogen sulfide gas. The objective of this paper is to investigate the performance of an airlift bioreactor fed with high concentrations of H2S with special emphasis on the effect of pH in combination with other factors such as H2S loading rate, oxygen availability, and sulfide accumulation. H2S inlet concentrations between 1,008 ppm and 31,215 ppm were applied and elimination capacities up to 113 g H2S m−3 h−1 were achieved in the airlift bioreactor under investigation at a pH range 6.5–8.5. Acidic pH values reduced the elimination capacity. Elemental sulfur recovery up to 95% was achieved under oxygen limited conditions (DO < 0.2 mg/L) and at higher pH values. The sulfur oxidizing bacteria in the bioreactor tolerated accumulated dissolved sulfide concentrations >500 mg/L at pH values 8.0–8.5, and near 100% removal efficiency was achieved. Overall, the resident microorganisms in the studied airlift bioreactor favored pH values in the alkaline range. The bioreactor performance in terms of elimination capacity and sulfur recovery was better at pH range 8–8.5. PMID:25147857

  12. Mesoporous TiO2 Nanocrystals/Graphene as an Efficient Sulfur Host Material for High-Performance Lithium-Sulfur Batteries.

    PubMed

    Li, Yuanyuan; Cai, Qifa; Wang, Lei; Li, Qingwei; Peng, Xiang; Gao, Biao; Huo, Kaifu; Chu, Paul K

    2016-09-14

    Rechargeable lithium-sulfur (Li-S) batteries are promising in high-energy storage due to the large specific energy density of about 2600 W h kg(-1). However, the low conductivity of sulfur and discharge products as well as polysulfide-shuttle effect between the cathode and anode hamper applications of Li-S batteries. Herein, we describe a novel and efficient S host material consisting of mesoporous TiO2 nanocrystals (NCs) fabricated in situ on reduced graphene oxide (rGO) for Li-S batteries. The TiO2@rGO hybrid can be loaded with 72 wt % sulfur. The strong chemisorption ability of the TiO2 NCs toward polysulfide combined with high electrical conductivity of rGO effectively localize the soluble polysulfide species within the cathode and facilitate electron and Li ions transport to/from the cathode materials. The sulfur-incorporated TiO2@rGO hybrid (S/TiO2@rGO) shows large capacities of 1116 and 917 mA h g(-1) at the current densities of 0.2 and 1 C (1 C = 1675 mA g(-1)) after 100 cycles, respectively. When the current density is increased 20 times from 0.2 to 4 C, 60% capacity is retained, thereby demonstrating good cycling stability and rate capability. The synergistic effects of TiO2 NCs toward effective chemisorption of polysulfides and conductive rGO with high electron mobility make a promising application of S/TiO2@rGO hybrid in high-performance Li-S batteries.

  13. Corrosion-resistant coatings for high-temperature high-sulfur-activity applications. Final report

    SciTech Connect

    Selman, J.R.

    1994-02-01

    The research described in this report is intended to assistant in developing the technology for the production of molybdenum and molybdenum carbide coatings. These coatings have the potential to serve as an alternative to present methods of protecting metal parts at positive potential, of high-temperature sulfur or sulfide batteries. Two methods have been employed. In Task 1, Study of Molybdenum Carbide Electrodeposition from Oxide Based Molten Salts, dense, well-adherent molybdenum carbide coatings have been deposited on mild steel substrates by electrochemical deposition from a Na{sub 2}WO{sub 4}-K{sub 2}WO{sub 4} molten bath containing alkali molybdates and carbonates. Coatings with thicknesses up to 30 {mu}m have been prepared at cathodic current densities between 30 and 50 mA.cm{sup {minus}2} under air as ambient atmosphere. Addition of Na{sub 2}B{sub 4}O{sub 7} to the basic non-lithium bath composition causes significant quality and morphology improvements. It is shown that the initial stages of the molybdenum carbide electrodeposition can be described by a model involving instantaneous nucleation and 3-D diffusion-controlled growth. In Task 2, Preparation of Mo and Mo{sub 2}C by Plasma-Enhanced Chemical Vapor Deposition, using factorial experimental design, a series of experiments has been carried out to investigate the PECVD process with Mo(CO){sub 6} as a precursor. Information about the effects of the chamber pressure, saturator temperature, gas composition and gas flow rate was obtained by experiments. Elemental analysis of the thin film was carried out by Auger electron spectroscopy. Further investigations are being carried out on the basis of thermodynamics, heterogeneous kinetics, and mass transport, in conjunction with measurements of evaporation rate and analysis of the solid and gaseous phases.

  14. High temperature solar thermochemical processing - Hydrogen and sulfur from hydrogen sulfide

    NASA Astrophysics Data System (ADS)

    Noring, J. E.; Fletcher, E. A.

    1982-08-01

    Sunlight, concentrated to high intensities, has a rarely recognized potential for adding process heat to reactors at high temperatures. Hydrogen sulfide is a by-product of the sweetening of fossil fuels. In this paper, by way of example, the production of hydrogen and sulfur from hydrogen sulfide is used as a device for showing how solar processing might be considered as a successor to a currently used industrial process, the Claus process. It is concluded that this and other processes should be explored as means of using as well as storing solar energy.

  15. Li2S nanocomposites underlying high-capacity and cycling stability in all-solid-state lithium-sulfur batteries

    NASA Astrophysics Data System (ADS)

    Nagao, Motohiro; Hayashi, Akitoshi; Tatsumisago, Masahiro; Ichinose, Takahiro; Ozaki, Tomoatsu; Togawa, Yoshihiko; Mori, Shigeo

    2015-01-01

    All-solid-state sulfur-based rechargeable lithium batteries have been expected to have superior energy density and high reliability so far. In general, the solid-solid interface between electrode and electrolyte particles has strong influence on the cell performance. Recently it is realized that all-solid-state lithium-sulfur batteries exhibit good cycling performance by reducing the particle size down to submicron scale. However, the origin of excellent reversibility has not been understood. Here we clearly demonstrate Li2S nanocomposites underlying high-capacity and cycling stability in all-solid-state lithium-sulfur batteries. Through high-resolution transmission electron microscopy (TEM) and energy-dispersed X-ray (EDX) spectroscopy experiments, reversible structural and morphological changes at the nanoscale during the full-electrochemical cycles in next-generation all-solid-state lithium-sulfur batteries have been revealed for the first time. Reversible variations during cycles between crystallization and amorphization of sulfur-based active nanoparticles are responsible for the feasibility of the high capacity and cycling stability. The smooth and adhesive interface between them is truly realized at the nanoscale, which is fabricated by mechanical milling technique. Our experimental findings will lead to new route to generate the sulfur-based rechargeable batteries with high-capacity and cycling stability.

  16. In situ coating of Poly(3,4-ethylenedioxythiophene) on sulfur cathode for high performance lithium-sulfur batteries

    NASA Astrophysics Data System (ADS)

    Song, Jongchan; Noh, Hyungjun; Lee, Jinhong; Nah, In-Wook; Cho, Won-Il; Kim, Hee-Tak

    2016-11-01

    Polysulfide (PS) shuttle, which is one of the critical problems that need to be addressed for realizing lithium sulfur batteries, can be suppressed by confining PSs within microporous or mesoporous templates. However, PS dissolution through the external opening of the templates has to be further prevented. In this work, a poly (3,4-ethylenedioxythiophene) (PEDOT) layer is formed in situ on the CMK-3/S cathode by inducing the electro-oxidative polymerization of the EDOT monomer included in electrolytes during pre-charging. The PEDOT layer covering the external cathode surface functions as a PS blocking layer, which suppresses the PS shuttle and, thus, improves the cycling stability. The spectroscopic analysis indicates that the PEDOT layer reduces the decomposition of the electrolyte by preventing any reaction between the active PS species and electrolytes. Therefore, the in situ formation of the PS blocking layer from the electrolyte additive provides a simple and effective method to improve the cycling stability of lithium sulfur batteries.

  17. Oxygen and sulfur isotope fractionation during methane dependent sulfate reduction in high pressure continuous incubation studies

    NASA Astrophysics Data System (ADS)

    Deusner, C.; Brunner, B.; Holler, T.; Widdel, F.; Ferdelman, T. G.

    2009-12-01

    The anaerobic oxidation of methane (AOM) coupled to sulfate reduction in marine sediments is an important sink in the global methane budget. However, many aspects of methane dependent sulfate reduction are not fully understood. We developed a novel high pressure biotechnical system to simulate marine conditions with high concentrations of dissolved gases, e.g. at gas seeps and gas hydrate systems. The system allows for batch, fed-batch and continuous gas-phase free incubation. We employ this system to study the kinetics and isotope fractionation during AOM at varying methane partial pressures up to 10 MPa. We present the results of long-term continuous and fed-batch incubations with highly active naturally enriched biomass from microbial mats from the Black Sea. During these experiments the methane partial pressure was increased stepwise from 0.1 to 10 MPa. The methane dependent sulfate reduction rate increased from 0.1 mmol/l/d to 3.5 mmol/l/d resulting from the increase in methane concentration and microbial growth. Sulfate reduction was negligible in the absence of methane. The sulfur and oxygen isotope fractionation during sulfate reduction was strongly influenced by the concentration of dissolved methane. Sulfur isotope fractionation was highest at low methane concentrations, and lowest at high methane concentrations. Relative to sulfate reduction rates, oxygen isotope exchange between sulfate and water was highest at low methane concentrations, and lowest at high methane concentrations.

  18. Superconducting H5S2 phase in sulfur-hydrogen system under high-pressure

    PubMed Central

    Ishikawa, Takahiro; Nakanishi, Akitaka; Shimizu, Katsuya; Katayama-Yoshida, Hiroshi; Oda, Tatsuki; Suzuki, Naoshi

    2016-01-01

    Recently, hydrogen sulfide was experimentally found to show the high superconducting critical temperature (Tc) under high-pressure. The superconducting Tc shows 30–70 K in pressure range of 100–170 GPa (low-Tc phase) and increases to 203 K, which sets a record for the highest Tc in all materials, for the samples annealed by heating it to room temperature at pressures above 150 GPa (high-Tc phase). Here we present a solid H5S2 phase predicted as the low-Tc phase by the application of the genetic algorithm technique for crystal structure searching and first-principles calculations to sulfur-hydrogen system under high-pressure. The H5S2 phase is thermodynamically stabilized at 110 GPa, in which asymmetric hydrogen bonds are formed between H2S and H3S molecules. Calculated Tc values show 50–70 K in pressure range of 100–150 GPa within the harmonic approximation, which can reproduce the experimentally observed low-Tc phase. These findings give a new aspect of the excellent superconductivity in compressed sulfur-hydrogen system. PMID:26983593

  19. Superconducting H5S2 phase in sulfur-hydrogen system under high-pressure

    NASA Astrophysics Data System (ADS)

    Ishikawa, Takahiro; Nakanishi, Akitaka; Shimizu, Katsuya; Katayama-Yoshida, Hiroshi; Oda, Tatsuki; Suzuki, Naoshi

    2016-03-01

    Recently, hydrogen sulfide was experimentally found to show the high superconducting critical temperature (Tc) under high-pressure. The superconducting Tc shows 30–70 K in pressure range of 100–170 GPa (low-Tc phase) and increases to 203 K, which sets a record for the highest Tc in all materials, for the samples annealed by heating it to room temperature at pressures above 150 GPa (high-Tc phase). Here we present a solid H5S2 phase predicted as the low-Tc phase by the application of the genetic algorithm technique for crystal structure searching and first-principles calculations to sulfur-hydrogen system under high-pressure. The H5S2 phase is thermodynamically stabilized at 110 GPa, in which asymmetric hydrogen bonds are formed between H2S and H3S molecules. Calculated Tc values show 50–70 K in pressure range of 100–150 GPa within the harmonic approximation, which can reproduce the experimentally observed low-Tc phase. These findings give a new aspect of the excellent superconductivity in compressed sulfur-hydrogen system.

  20. Functional Organosulfide Electrolyte Promotes an Alternate Reaction Pathway to Achieve High Performance in Lithium-Sulfur Batteries.

    PubMed

    Chen, Shuru; Dai, Fang; Gordin, Mikhail L; Yu, Zhaoxin; Gao, Yue; Song, Jiangxuan; Wang, Donghai

    2016-03-18

    Lithium-sulfur (Li-S) batteries have recently received great attention because they promise to provide energy density far beyond current lithium ion batteries. Typically, Li-S batteries operate by conversion of sulfur to reversibly form different soluble lithium polysulfide intermediates and insoluble lithium sulfides through multistep redox reactions. Herein, we report a functional electrolyte system incorporating dimethyl disulfide as a co-solvent that enables a new electrochemical reduction pathway for sulfur cathodes. This pathway uses soluble dimethyl polysulfides and lithium organosulfides as intermediates and products, which can boost cell capacity and lead to improved discharge-charge reversibility and cycling performance of sulfur cathodes. This electrolyte system can potentially enable Li-S batteries to achieve high energy density.

  1. Sulfur cycling and methanogenesis primarily drive microbial colonization of the highly sulfidic Urania deep hypersaline basin.

    PubMed

    Borin, Sara; Brusetti, Lorenzo; Mapelli, Francesca; D'Auria, Giuseppe; Brusa, Tullio; Marzorati, Massimo; Rizzi, Aurora; Yakimov, Michail; Marty, Danielle; De Lange, Gert J; Van der Wielen, Paul; Bolhuis, Henk; McGenity, Terry J; Polymenakou, Paraskevi N; Malinverno, Elisa; Giuliano, Laura; Corselli, Cesare; Daffonchio, Daniele

    2009-06-09

    Urania basin in the deep Mediterranean Sea houses a lake that is >100 m deep, devoid of oxygen, 6 times more saline than seawater, and has very high levels of methane and particularly sulfide (up to 16 mM), making it among the most sulfidic water bodies on Earth. Along the depth profile there are 2 chemoclines, a steep one with the overlying oxic seawater, and another between anoxic brines of different density, where gradients of salinity, electron donors and acceptors occur. To identify and differentiate the microbes and processes contributing to the turnover of organic matter and sulfide along the water column, these chemoclines were sampled at a high resolution. Bacterial cell numbers increased up to a hundredfold in the chemoclines as a consequence of elevated nutrient availability, with higher numbers in the upper interface where redox gradient was steeper. Bacterial and archaeal communities, analyzed by DNA fingerprinting, 16S rRNA gene libraries, activity measurements, and cultivation, were highly stratified and metabolically more active along the chemoclines compared with seawater or the uniformly hypersaline brines. Detailed analysis of 16S rRNA gene sequences revealed that in both chemoclines delta- and epsilon-Proteobacteria, predominantly sulfate reducers and sulfur oxidizers, respectively, were the dominant bacteria. In the deepest layers of the basin MSBL1, putatively responsible for methanogenesis, dominated among archaea. The data suggest that the complex microbial community is adapted to the basin's extreme chemistry, and the elevated biomass is driven largely by sulfur cycling and methanogenesis.

  2. Sulfur Earth

    NASA Astrophysics Data System (ADS)

    de Jong, B. H.

    2007-12-01

    Variations in surface tension affect the buoyancy of objects floating in a liquid. Thus an object floating in water will sink deeper in the presence of dishwater fluid. This is a very minor but measurable effect. It causes for instance ducks to drown in aqueous solutions with added surfactant. The surface tension of liquid iron is very strongly affected by the presence of sulfur which acts as a surfactant in this system varying between 1.9 and 0.4 N/m at 10 mass percent Sulfur (Lee & Morita (2002), This last value is inferred to be the maximum value for Sulfur inferred to be present in the liquid outer core. Venting of Sulfur from the liquid core manifests itself on the Earth surface by the 105 to 106 ton of sulfur vented into the atmosphere annually (Wedepohl, 1984). Inspection of surface Sulfur emission indicates that venting is non-homogeneously distributed over the Earth's surface. The implication of such large variation in surface tension in the liquid outer core are that at locally low Sulfur concentration, the liquid outer core does not wet the predominantly MgSiO3 matrix with which it is in contact. However at a local high in Sulfur, the liquid outer core wets this matrix which in the fluid state has a surface tension of 0.4 N/m (Bansal & Doremus, 1986), couples with it, and causes it to sink. This differential and diapiric movement is transmitted through the essentially brittle mantle (1024 Pa.s, Lambeck & Johnson, 1998; the maximum value for ice being about 1030 Pa.s at 0 K, in all likely hood representing an upper bound of viscosity for all materials) and manifests itself on the surface by the roughly 20 km differentiation, about 0.1 % of the total mantle thickness, between topographical heights and lows with concomitant lateral movement in the crust and upper mantle resulting in thin skin tectonics. The brittle nature of the medium though which this movement is transmitted suggests that the extremes in topography of the D" layer are similar in range to

  3. Influence of sulfur-bearing polyatomic species on high precision measurements of Cu isotopic composition

    USGS Publications Warehouse

    Pribil, M.J.; Wanty, R.B.; Ridley, W.I.; Borrok, D.M.

    2010-01-01

    An increased interest in high precision Cu isotope ratio measurements using multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) has developed recently for various natural geologic systems and environmental applications, these typically contain high concentrations of sulfur, particularly in the form of sulfate (SO42-) and sulfide (S). For example, Cu, Fe, and Zn concentrations in acid mine drainage (AMD) can range from 100??g/L to greater than 50mg/L with sulfur species concentrations reaching greater than 1000mg/L. Routine separation of Cu, Fe and Zn from AMD, Cu-sulfide minerals and other geological matrices usually incorporates single anion exchange resin column chromatography for metal separation. During chromatographic separation, variable breakthrough of SO42- during anion exchange resin column chromatography into the Cu fractions was observed as a function of the initial sulfur to Cu ratio, column properties, and the sample matrix. SO42- present in the Cu fraction can form a polyatomic 32S-14N-16O-1H species causing a direct mass interference with 63Cu and producing artificially light ??65Cu values. Here we report the extent of the mass interference caused by SO42- breakthrough when measuring ??65Cu on natural samples and NIST SRM 976 Cu isotope spiked with SO42- after both single anion column chromatography and double anion column chromatography. A set of five 100??g/L Cu SRM 976 samples spiked with 500mg/L SO42- resulted in an average ??65Cu of -3.50?????5.42??? following single anion column separation with variable SO42- breakthrough but an average concentration of 770??g/L. Following double anion column separation, the average SO42-concentration of 13??g/L resulted in better precision and accuracy for the measured ??65Cu value of 0.01?????0.02??? relative to the expected 0??? for SRM 976. We conclude that attention to SO42- breakthrough on sulfur-rich samples is necessary for accurate and precise measurements of ??65Cu and may require

  4. Infrared detection of Criegee intermediates formed during the ozonolysis of β-pinene and their reactivity towards sulfur dioxide.

    PubMed

    Ahrens, Jennifer; Carlsson, Philip T M; Hertl, Nils; Olzmann, Matthias; Pfeifle, Mark; Wolf, J Lennard; Zeuch, Thomas

    2014-01-13

    Recently, direct kinetic experiments have shown that the oxidation of sulfur dioxide to sulfur trioxide by reaction with stabilized Criegee intermediates (CIs) is an important source of sulfuric acid in the atmosphere. So far, only small CIs, generated in photolysis experiments, have been directly detected. Herein, it is shown that large, stabilized CIs can be detected in the gas phase by FTIR spectroscopy during the ozonolysis of β-pinene. Their transient absorption bands between 930 and 830 cm(-1) appear only in the initial phase of the ozonolysis reaction when the scavenging of stabilized CIs by the reaction products is slow. The large CIs react with sulfur dioxide to give sulfur trioxide and nopinone with a yield exceeding 80%. Reactant consumption and product formation in time-resolved β-pinene ozonolysis experiments in the presence of sulfur dioxide have been kinetically modeled. The results suggest a fast reaction of sulfur dioxide with CIs arising from β-pinene ozonolysis.

  5. Hierarchical sulfur electrodes as a testing platform for understanding the high-loading capability of Li-S batteries

    NASA Astrophysics Data System (ADS)

    Chung, Sheng-Heng; Chang, Chi-Hao; Manthiram, Arumugam

    2016-12-01

    Lithium-sulfur (Li-S) batteries are considered as an attractive electrochemical energy storage system due to the high theoretical capacity of sulfur (1,675 mA h g-1). However, high-loading sulfur cathodes would need to be employed for the Li-S cells to be practical, but the resulting poor cell cyclability and severe electrode degradation hamper their development. Here, we present a hierarchical sulfur cathode as a testing platform for understanding the high-loading capability of Li-S batteries. The hierarchical cathode presents good electrochemical utilization of above 70%, stable cyclability for 500-1,000 cycles, and high sulfur loadings of 4.2-10.0 mg cm-2. The exploration of the activation and the polysulfide-retention processes of the high-loading cathodes illustrates that the electrochemical stability mainly results from the stabilization of dissolved polysulfides within the cathode region as the electrochemically active catholyte. Therefore, the utilization of stabilized polysulfide migration might be a meaningful opportunity for designing high-loading cathodes and further improving their electrochemical stability and long-term cyclability.

  6. Sulfur isotope dynamics in two central european watersheds affected by high atmospheric deposition of SO x

    NASA Astrophysics Data System (ADS)

    Novák, Martin; Kirchner, James W.; Groscheová, Hana; Havel, Miroslav; Černý, Jiří; Krejčí, Radovan; Buzek, František

    2000-02-01

    Sulfur fluxes and δ34S values were determined in two acidified small watersheds located near the Czech-German border, Central Europe. Sulfur of sulfate aerosol in the broader region (mean δ 34S of 7.5‰ CDT) was isotopically heavier than sulfur of airborne SO 2 (mean δ 34S of 4.7‰). The annual atmospheric S deposition to the Jezeřı´ watershed decreased markedly in 1993, 1994, and 1995 (40, 33, and 29 kg/ ha · yr), reflecting reductions in industrial S emissions. Sulfur export from Jezeří via surface discharge was twice atmospheric inputs, and increased from 52 to 58 to 85 kg/ha · yr over the same three-year period. The δ 34S value of Jezeřı´ streamflow was 4.5 ± 0.3‰, intermediate between the average atmospheric deposition (5.4 ± 0.2‰) and soil S (4.0 ± 0.5‰), suggesting that the excess sulfate in runoff comes from release of S from the soil. Bedrock is not a plausible source of the excess S, because its S concentration is very low (<0.003 wt.%) and because its δ 34S value is too high (5.8‰) to be consistent with the δ 34S of runoff. A sulfur isotope mixing model indicated that release of soil S accounted for 64 ± 33% of sulfate S in Jezeřı´ discharge. Approximately 30% of total sulfate S in the discharge were organically cycled. At Načetı´n, the same sequence of δ34S IN > δ34S OUT > δ34S SOIL was observed. The seasonality found in atmospheric input (higher δ 34S in summer, lower δ 34S in winter) was preserved in shallow (<10 cm) soil water, but not in deeper soil water. δ 34S values of deeper (>10 cm) soil water (4.8 ± 0.2‰) were intermediate between those of atmospheric input (5.9 ± 0.3‰) and Nac̆etín soils (2.4 ± 0.1‰), again suggesting that remobilization of soil S accounts for a significant fraction (roughly 40 ± 10%) of the S in soil water at Načetı´n. The inventories of soil S at both of these sites are legacies of more intense atmospheric pollution during previous decades, and are large enough (740

  7. A low cost, high energy density and long cycle life potassium-sulfur battery for grid-scale energy storage

    SciTech Connect

    Lu, Xiaochuan; Bowden, Mark E.; Sprenkle, Vincent L.; Liu, Jun

    2015-08-15

    Alkali metal-sulfur batteries are attractive for energy storage applications because of their high energy density. Among the batteries, lithium-sulfur batteries typically use liquid in the battery electrolyte, which causes problems in both performance and safety. Sodium-sulfur batteries can use a solid electrolyte such as beta alumina but this requires a high operating temperature. Here we report a novel potassium-sulfur battery with K+-conducting beta-alumina as the electrolyte. Our studies indicate that liquid potassium exhibits much better wettability on the surface of beta-alumina compared to liquid sodium at lower temperatures. Based on this observation, we develop a potassium-sulfur battery that can operate at as low as 150°C with excellent performance. In particular, the battery shows excellent cycle life with negligible capacity fade in 1000 cycles because of the dense ceramic membrane. This study demonstrates a new battery with a high energy density, long cycle life, low cost and high safety, which is ideal for grid-scale energy storage.

  8. Production of a high energy, low sulfur fuel with the Carbondry{trademark} process

    SciTech Connect

    Simmons, J.; Simmons, J.

    1995-12-31

    Carbontee`s Carbondry{trademark} coal drying process has been proven to be a versatile, cost effective technology, ideally suited for drying sub-bituminous and lignite coal. The ability to process a wide variety of low rank coals is a significant achievement. A typical sub-bituminous coal product is a high Btu, low sulfur fuel that contains from 11,000--11,800 Btu/lb, 7--10% moisture, and less than 0.5% sulfur (< 0.8 lbs. SO{sub 2}/MMBtu). Then enriched fuel is a 2 x 0 inch product which can be shipped in open top railroad cars. The capability of Carbontee`s patented technology has been well demonstrated at Carbontee Corporation`s coal drying pilot plant in Bismarck, ND, which has processed sub-bituminous coal from six Wyoming Powder River Basin Mines as well as from Montana and Indonesia. The Carbontee plant has also demonstrated the reliability of the system having operated at 95% of schedule time. The Carbondry Process involves two stages, a hot oil first stage drying unit and a hot flue gas second stage drying unit. The process provides a barrier on the surface and changes the chemistry within the interior of the coal to protect against moisture reabsorption and spontaneous heating. Two Carbondry plants are currently under consideration, a 1,000,000 TPY plant in Wyoming and a 500,000 to 1,000,000 TPY plant in Indonesia.

  9. Sulfur removal from high-sulfur Illinois coal by low-temperature perchloroethylene (PCE) extraction. Final technical report, 1 September, 1992--31 August, 1993

    SciTech Connect

    Chou, M.I.M.; Lytle, J.M.; Ruch, R.R.; Kruse, C.W.; Chaven, C.; Hackley, K.C.; Hughes, R.E.; Harvey, R.D.; Frost, J.K.; Buchanan, D.H.; Stucki, J.W.; Huffman, G.P.; Huggins, F.E.

    1993-12-31

    The Midwest Ore Processing Co. (MWOPC) has reported a precombustion coal desulfurization process using perchloroethylene (PCE) at 120 C to remove up to 70% of the organic sulfur. The purposes of this research were to independently confirm and possibly to improve the organic sulfur removal from Illinois coals with the PCE desulfurization and to verify the ASTM forms-of-sulfur determination for evaluation of the process. An additional goal was to develop a dechlorination procedure to remove excess PCE from the PCE-treated coal. A laboratory scale operation of the MWOPC PCE desulfurization process was demonstrated, and a dechlorination procedure to remove excess PCE from the PCE-treated coal was developed. The authors have determined that PCE desulfurization removed mainly elemental sulfur from coal. The higher the level of coal oxidization, the larger the amount of elemental sulfur that is removed by PCE extraction. The increased elemental sulfur during short-term preoxidation is found to be pH dependent and is attributed to coal pyrite oxidation under acidic (pH < 2) conditions. The non-ASTM sulfur analyses confirmed the hypothesis that the elemental sulfur produced by oxidation of pyrite complicates the interpretation of analytical data for PCE process evaluations when only the ASTM forms-of-sulfur is used. When the ASTM method is used alone, the elemental sulfur removed during PCE desulfurization is counted as organic sulfur. A study using model compounds suggests that mild preoxidation treatment of coal described by MWOPC for removal of organic sulfur does not produce enough oxidized organic sulfur to account for the amounts of sulfur removal reported. Furthermore, when oxidation of coal-like organosulfur compounds does occur, the products are inconsistent with production of elemental sulfur, the product reported by MWOPC. Overall, it is demonstrated that the PCE process is not suitable for organic sulfur removal.

  10. Clean coal technology and emissions trading: Is there a future for high-sulfur coal under the Clean Air Act Amendments of 1990?

    SciTech Connect

    Bailey, K.A.; South, D.W.; McDermott, K.A. |

    1991-12-31

    The near-term and long-term fate of high-sulfur coal is linked to utility compliance plans, the evolution of emission allowance trading, state and federal regulation, and technological innovation. All of these factors will play an implicit role in the demand for high-sulfur coal. This paper will explore the potential impact that emissions trading will have on high-sulfur coal utilization by electric utilities. 28 refs., 6 figs., 4 tabs.

  11. Clean coal technology and emissions trading: Is there a future for high-sulfur coal under the Clean Air Act Amendments of 1990

    SciTech Connect

    Bailey, K.A.; South, D.W. ); McDermott, K.A. Illinois State Univ., Normal, IL )

    1991-01-01

    The near-term and long-term fate of high-sulfur coal is linked to utility compliance plans, the evolution of emission allowance trading, state and federal regulation, and technological innovation. All of these factors will play an implicit role in the demand for high-sulfur coal. This paper will explore the potential impact that emissions trading will have on high-sulfur coal utilization by electric utilities. 28 refs., 6 figs., 4 tabs.

  12. Self-assembled sulfur/reduced graphene oxide nanoribbon paper as a free-standing electrode for high performance lithium-sulfur batteries.

    PubMed

    Liu, Yang; Wang, Xuzhen; Dong, Yanfeng; Tang, Yongchao; Wang, Luxiang; Jia, Dianzeng; Zhao, Zongbin; Qiu, Jieshan

    2016-10-25

    Flexible, interconnected sulfur/reduced graphene oxide nanoribbon paper (S/RGONRP) is synthesized through S(2-) reduction and evaporation induced self-assembly processes. The in situ formed sulfur atoms chemically bonded with the surface of reduced graphene oxide nanoribbons and were physically trapped by the compact assembly, which make the hybrid a suitable cathode material for lithium-sulfur batteries.

  13. Electric Power Research Institute, High-Sulfur Test Center report to the Steering Committee, July 1991

    SciTech Connect

    Not Available

    1991-01-01

    Operation and testing continued this month at the High Sulfur Test Center on the Pilot Wet Scrubber, Mini-Pilot Wet Scrubber and the Spray Dryer Systems. The Pilot continued testing under the High Performance test block program and the Mini-Pilot continued testing under the Formate Forced Oxidation test block. The HSSD testing to investigate the effects that ambient temperature and humidity have on SO{sub 2} removal was completed. Dry alkaline injection testing was started to remove SO{sub 3} and HCl from flue gas which removes visible plumes. Construction upgrades and system shakedown continued on the Cold-Side Selective Catalytic Reduction (SCR) system in preparation for start-up. (VC)

  14. Electric Power Research Institute, High-Sulfur Test Center report to the Steering Committee, July 1991

    SciTech Connect

    Not Available

    1991-12-31

    Operation and testing continued this month at the High Sulfur Test Center on the Pilot Wet Scrubber, Mini-Pilot Wet Scrubber and the Spray Dryer Systems. The Pilot continued testing under the High Performance test block program and the Mini-Pilot continued testing under the Formate Forced Oxidation test block. The HSSD testing to investigate the effects that ambient temperature and humidity have on SO{sub 2} removal was completed. Dry alkaline injection testing was started to remove SO{sub 3} and HCl from flue gas which removes visible plumes. Construction upgrades and system shakedown continued on the Cold-Side Selective Catalytic Reduction (SCR) system in preparation for start-up. (VC)

  15. Search for high-Tc conventional superconductivity at megabar pressures in the lithium-sulfur system

    NASA Astrophysics Data System (ADS)

    Kokail, Christian; Heil, Christoph; Boeri, Lilia

    2016-08-01

    Motivated by the recent report of superconductivity above 200 K in ultra-dense hydrogen sulfide, we search for high-TC conventional superconductivity in the phase diagram of the binary Li-S system, using ab initio methods for crystal structure prediction and linear response calculations for the electron-phonon coupling. We find that at pressures higher than 20 GPa, several new compositions, besides the known Li2S , are stabilized; many exhibit electride-like interstitial charge localization observed in other alkali-metal compounds. Of all predicted phases, only an fcc phase of Li3S , metastable before 640 GPa, exhibits a sizable TC, in contrast to what is observed in sulfur and phosphorus hydrides, where several stoichiometries lead to high TC. We attribute this difference to 2 s -2 p hybridization and avoided core overlap, and predict similar behavior for other alkali-metal compounds.

  16. Pyrolysis of waste electrical and electronic equipment: effect of antinomy trioxide on the pyrolysis of styrenic polymers.

    PubMed

    Hall, W J; Bhaskar, T; Merpati, N M M; Muto, A; Sakata, Y; Williams, P T

    2007-09-01

    This work has investigated the effect that antimony trioxide has on the pyrolysis of styrenic polymers and the effect that different types of brominated flame retardants used in plastics have on the composition of the pyrolysis products. Brominated high impact polystyrene (Br-HIPS) which contained either 5% or 0% antimony trioxide and either decabromodiphenyl oxide (DDO) or decabromodiphenyl ethane (DDE) was pyrolysed in a fixed bed reactor at 430 degrees C. Some experiments on the fixed bed reactor involved mixing the Br-HIPS with polystyrene. The gaseous products were analysed by GC-FID and GC-TCD and it was found that antimony trioxide caused an increase in the proportion of ethane and ethene and suppressed the proportion of butane and butene. When DDE was the flame retardant increased proportions of ethane and ethene were found in the pyrolysis gas compared to when DDO used. When polystyrene was mixed with the Br-HIPS it suppressed the trends observed in the gas composition during the pyrolysis of Br-HIPS. The pyrolysis oils were characterised using FT-IR, GC-MS, GC-FID, and GC-ECD. It was found that the plastic which did not contain antimony trioxide pyrolysed to form mainly toluene, ethylbenzene, styrene, cumene, and alpha-methylstyrene. The oils produced from the pyrolysis of the plastic that contained antimony trioxide did not contain any styrene or alpha-methylstyrene, but instead contained greater concentrations of ethylbenzene and cumene. The absence of styrene and alpha-methylstyrene from the pyrolysis oil occurred even when the Br-HIPS was mixed with polystyrene. GC-ECD analysis of the oils showed that the plastics which did not contain antimony trioxide pyrolysed to form (1-bromoethyl)benzene, which was totally absent from the pyrolysis oils when antimony trioxide was present in the plastic.

  17. Mechanism study on the sulfidation of ZnO with sulfur and iron oxide at high temperature

    PubMed Central

    Han, Junwei; Liu, Wei; Zhang, Tianfu; Xue, Kai; Li, Wenhua; Jiao, Fen; Qin, Wenqing

    2017-01-01

    The mechanism of ZnO sulfidation with sulfur and iron oxide at high temperatures was studied. The thermodynamic analysis, sulfidation behavior of zinc, phase transformations, morphology changes, and surface properties were investigated by HSC 5.0 combined with FactSage 7.0, ICP, XRD, optical microscopy coupled with SEM-EDS, and XPS. The results indicate that increasing temperature and adding iron oxide can not only improve the sulfidation of ZnO but also promote the formation and growth of ZnS crystals. Fe2O3 captured the sulfur in the initial sulfidation process as iron sulfides, which then acted as the sulfurizing agent in the late period, thus reducing sulfur escape at high temperatures. The addition of carbon can not only enhance the sulfidation but increase sulfur utilization rate and eliminate the generation of SO2. The surfaces of marmatite and synthetic zinc sulfides contain high oxygen due to oxidation and oxygen adsorption. Hydroxyl easily absorbs on the surface of iron-bearing zinc sulfide (Zn1−xFexS). The oxidation of synthetic Zn1−xFexS is easier than marmatite in air. PMID:28186156

  18. Understanding the Redox Obstacles in High Sulfur-Loading Li-S Batteries and Design of an Advanced Gel Cathode.

    PubMed

    Zu, Chenxi; Li, Longjun; Guo, Jianhe; Wang, Shaofei; Fan, Donglei; Manthiram, Arumugam

    2016-04-07

    Lithium-sulfur batteries with a high energy density are being considered a promising candidate for next-generation energy storage. However, realization of Li-S batteries is plagued by poor sulfur utilization due to the shuttle of intermediate lithiation products between electrodes and its dynamic redistribution. To optimize the sulfur utilization, an understanding of its redox behavior is essential. Herein, we report a gel cathode consisting of a polysulfide-impregnated O- and N-doped porous carbon and an independent, continuous, and highly conducting 3-dimensional graphite film as the charge-transfer network. This design decouples the function of electron conduction and polysulfide absorption, which is beneficial for understanding the sulfur redox behavior and identifying the dominant factors leading to cell failure when the cells have high sulfur content and insufficient electrolyte. This design also opens up new prospects of tuning the properties of Li-S batteries via separately designing the material functions of electron conduction and polysulfide absorption.

  19. Mechanism study on the sulfidation of ZnO with sulfur and iron oxide at high temperature

    NASA Astrophysics Data System (ADS)

    Han, Junwei; Liu, Wei; Zhang, Tianfu; Xue, Kai; Li, Wenhua; Jiao, Fen; Qin, Wenqing

    2017-02-01

    The mechanism of ZnO sulfidation with sulfur and iron oxide at high temperatures was studied. The thermodynamic analysis, sulfidation behavior of zinc, phase transformations, morphology changes, and surface properties were investigated by HSC 5.0 combined with FactSage 7.0, ICP, XRD, optical microscopy coupled with SEM-EDS, and XPS. The results indicate that increasing temperature and adding iron oxide can not only improve the sulfidation of ZnO but also promote the formation and growth of ZnS crystals. Fe2O3 captured the sulfur in the initial sulfidation process as iron sulfides, which then acted as the sulfurizing agent in the late period, thus reducing sulfur escape at high temperatures. The addition of carbon can not only enhance the sulfidation but increase sulfur utilization rate and eliminate the generation of SO2. The surfaces of marmatite and synthetic zinc sulfides contain high oxygen due to oxidation and oxygen adsorption. Hydroxyl easily absorbs on the surface of iron-bearing zinc sulfide (Zn1‑xFexS). The oxidation of synthetic Zn1‑xFexS is easier than marmatite in air.

  20. Aubrite basalt vitrophyres: High sulfur silicate melts and a snapshot of aubrite formation. [Abstract only

    NASA Technical Reports Server (NTRS)

    Fogel, R. A.

    1994-01-01

    Two aubrite basalt vitrophyre clasts have been found within AMNH thin sections from the Parsa EH3 chondrite and the Khor Temiki aubrite. Polished sections of the Parsa Aubrite Inclusion (PAI) and the Khor Temiki Inclusion (KTI) were studied by optical, electron probe microanalysis (EPMA), and scanning electron microscopy (SEM) techniques with broad-beam and low absorbed EPMA currents used to minimize glass volatile loss. Some data have previously been reported for PAI and KTI may possibly correlate to a previously reported inclusion in Khor Tiimiki. In polished sections, PAI and KTI are approximately equal 4 mm in diameter and contain a large volume of glass. The clasts have similar textural characteristics and are akin to lunar vitrophyre textures. The glasses have high alkali rhyodacitic compositions Al-though PAI is peraluminous, KTI is significantly peralkaline. Additionally, the glasses have elevated sulfur concentrations that are extremely high by geochemical standards. SEM examination for beam overlap of microscopic CaS, FeS, and (Mg, Mn, Fe) S inclusions showed no such contamination. Furthermore, homogeneity of glass S content and low FeO contents help rule out contamination. Materials research data show that under reducing conditions alumino-silicate melts can dissolve up to several weight percent sulfur in the absence of Fe. The high S and alkali contents, the lack of associated high shock features, and the rationalized phase equilibria suggest that PAI and KTI are igneous melting products of an E-chondrite-like source material. Although large-scale impact melting cannot totally be ruled out, the above observations eliminate the possibility of in-situ shock melting.

  1. Polyamidoamine dendrimer-based binders for high-loading lithium–sulfur battery cathodes

    SciTech Connect

    Bhattacharya, Priyanka; Nandasiri, Manjula I.; Lv, Dongping; Schwarz, Ashleigh M.; Darsell, Jens T.; Henderson, Wesley A.; Tomalia, Donald A.; Liu, Jun; Zhang, Ji-Guang; Xiao, Jie

    2016-01-01

    Lithium-sulfur (Li-S) batteries are regarded as one of the most promising candidates for next generation energy storage systems because of their ultra high theoretical specific energy. To realize the practical application of Li-S batteries, however, a high S active material loading is essential (>70 wt% in the carbon-sulfur (C-S) composite cathode and >2 mg cm-2 in the electrode). A critical challenge to achieving this high capacity in practical electrodes is the dissolution of the longer lithium polysulfide reaction intermediates in the electrolyte (resulting in loss of active material from the cathode and contamination of the anode due to the polysulfide shuttle mechanism). The binder material used for the cathode is therefore crucial as this is a key determinant of the bonding interactions between the active material (S) and electronic conducting support (C), as well as the maintenance of intimate contact between the electrode materials and current collector. The battery performance can thus be directly correlated with the choice of binder, but this has received only minimal attention in the relevant Li-S battery published literature. Here, we investigated the application of polyamidoamine (PAMAM) dendrimers as functional binders in Li-S batteries—a class of materials which has been unexplored for electrode design. By using dendrimers, it is demonstrated that high S loadings (>4 mg cm-2) can be easily achieved using "standard" (not specifically tailored) materials and simple processing methods. An exceptional electrochemical cycling performance was obtained (as compared to cathodes with conventional linear polymeric binders such as carboxymethyl cellulose (CMC) and styrene-butadiene rubber (SBR)) with >100 cycles and 85-98% capacity retention, thus demonstrating the significant utility of this new binder architecture which exhibits critical physicochemical properties and flexible nanoscale design parameters (CNDP's).

  2. Sandwich heterostructures of antimony trioxide and bismuth trioxide films: Structural, morphological and optical analysis

    NASA Astrophysics Data System (ADS)

    Condurache-Bota, Simona; Praisler, Mirela; Gavrila, Raluca; Tigau, Nicolae

    2017-01-01

    Thin film heterostructures can be advantageous since they either exhibit novel or a combination of the properties of their components. Here we propose sandwich-type of heterostructures made of antimony trioxide and bismuth trioxide thin films, which were deposited on glass substrates by thermal vacuum deposition at three substrate temperatures, 50° Celsius apart. Their morphology and optical properties are studied as compared to the corresponding monolayers. It was found that even small substrate temperature changes strongly influence their morphology, increasing their roughness, while the optical transmittance shows a slight decrease as compared with the individual layers. The corresponding absorption coefficient exhibits intermediate values as compared to the component oxides, while the energy bandgaps for the indirect allowed transitions move towards the Infrared when overlapping the antimony and bismuth trioxides.

  3. Aqueous leaching on high sulfur sub-bituminous coals, in Assam, India

    SciTech Connect

    Bimala P. Baruah; Binoy K. Saikia; Prabhat Kotoky; P. Gangadhar Rao

    2006-08-15

    Aqueous leaching of high sulfur sub-bituminous coals from Ledo and Baragolai collieries of Makum coal fields, in Assam, India, has been investigated with respect to time at different temperatures. Leaching at 25{sup o}C up to 120 h showed that the physicochemical characteristics viz., conductivity, acidity, TDS, and SO{sub 4}-2 ions, increase with the increase in time of leaching. The generation of highly acidic leachates at 1-1.5 h (pH 2.5) and 2 h (pH 3.1) for Ledo and Baragolai coals was observed, respectively. However, it remains stable up to 120 h. The concentration of major, minor, and trace elements and their mobility along with the loss of pyritic sulfur or depyritization were also reported. The release of metals (Fe, Mg, Bi, Al, V, Cu, Cd, Ni, Pb, and Mn) above the regulatory levels during leaching was evidenced. Depyritization was found to be 79.8, 82.9, 84.7, and 89.7% for Ledo and 70.49, 73.77, 75.41, and 77.05% for Baragolai coal at 15, 25, 35, and 45 {sup o}C, respectively. A pseudo-first-order kinetic relationship with activation energies (E) of 8.1477 and 5.2378 kJ mol{sup -1} with frequency factors (A) of 8.8405 x 10{sup -4} and 2.6494 x 10{sup -4} dm{sup 3} mol{sup -1} s{sup -1} was attributed to aqueous oxidation of pyrites in Ledo and Baragolai coals, respectively. The X-ray diffraction analysis and Fourier transform infrared spectroscopy patterns indicate the presence of illite, {alpha}-quartz, hematite, chlorite, rutile, calcite, and albite as mineral phases. This investigation justifies the formation of acid mine drainage by weathering of pyrites from coal during the mining of high sulfur Makum coal fields, in Assam, India, and demonstrates one of the possible routes for its formation. 39 refs., 3 figs. 9 tabs.

  4. Layer-by-Layer Assembled Architecture of Polyelectrolyte Multilayers and Graphene Sheets on Hollow Carbon Spheres/Sulfur Composite for High-Performance Lithium-Sulfur Batteries.

    PubMed

    Wu, Feng; Li, Jian; Su, Yuefeng; Wang, Jing; Yang, Wen; Li, Ning; Chen, Lai; Chen, Shi; Chen, Renjie; Bao, Liying

    2016-09-14

    In the present work, polyelectrolyte multilayers (PEMs) and graphene sheets are applied to sequentially coat on the surface of hollow carbon spheres/sulfur composite by a flexible layer-by-layer (LBL) self-assembly strategy. Owing to the strong electrostatic interactions between the opposite charged materials, the coating agents are very stable and the coating procedure is highly efficient. The LBL film shows prominent impact on the stability of the cathode by acting as not only a basic physical barrier, and more importantly, an ion-permselective film to block the polysulfides anions by Coulombic repulsion. Furthermore, the graphene sheets can help to stabilize the polyelectrolytes film and greatly reduce the inner resistance of the electrode by changing the transport of the electrons from a "point-to-point" mode to a more effective "plane-to-point'' mode. On the basis of the synergistic effect of the PEMs and graphene sheets, the fabricated composite electrode exhibits very stable cycling stability for over 200 cycles at 1 A g(-1), along with a high average Coulombic efficiency of 99%. With the advantages of rapid and controllable fabrication of the LBL coating film, the multifunctional architecture developed in this study should inspire the design of other lithium-sulfur cathodes with unique physical and chemical properties.

  5. Metatranscriptomic analysis of a high-sulfide aquatic spring reveals insights into sulfur cycling and unexpected aerobic metabolism.

    PubMed

    Spain, Anne M; Elshahed, Mostafa S; Najar, Fares Z; Krumholz, Lee R

    2015-01-01

    Zodletone spring is a sulfide-rich spring in southwestern Oklahoma characterized by shallow, microoxic, light-exposed spring water overlaying anoxic sediments. Previously, culture-independent 16S rRNA gene based diversity surveys have revealed that Zodletone spring source sediments harbor a highly diverse microbial community, with multiple lineages putatively involved in various sulfur-cycling processes. Here, we conducted a metatranscriptomic survey of microbial populations in Zodletone spring source sediments to characterize the relative prevalence and importance of putative phototrophic, chemolithotrophic, and heterotrophic microorganisms in the sulfur cycle, the identity of lineages actively involved in various sulfur cycling processes, and the interaction between sulfur cycling and other geochemical processes at the spring source. Sediment samples at the spring's source were taken at three different times within a 24-h period for geochemical analyses and RNA sequencing. In depth mining of datasets for sulfur cycling transcripts revealed major sulfur cycling pathways and taxa involved, including an unexpected potential role of Actinobacteria in sulfide oxidation and thiosulfate transformation. Surprisingly, transcripts coding for the cyanobacterial Photosystem II D1 protein, methane monooxygenase, and terminal cytochrome oxidases were encountered, indicating that genes for oxygen production and aerobic modes of metabolism are actively being transcribed, despite below-detectable levels (<1 µM) of oxygen in source sediment. Results highlight transcripts involved in sulfur, methane, and oxygen cycles, propose that oxygenic photosynthesis could support aerobic methane and sulfide oxidation in anoxic sediments exposed to sunlight, and provide a viewpoint of microbial metabolic lifestyles under conditions similar to those seen during late Archaean and Proterozoic eons.

  6. Evaluation of high Ni-Cr-Mo alloys for the construction of sulfur dioxide scrubber plants

    NASA Astrophysics Data System (ADS)

    Rajendran, N.; Rajeswari, S.

    1996-02-01

    Corrosion in wet lime/limestone systems used for flue gas desulfurization in thermal power plants is of great concern. The frequent variations in acidity and in chloride and fluoride ion concentrations experienced by such systems pose a serious threat to the materials of construction. Currently used materials mostly type 316L stainless steel often fail to meet their life expectancy. The present study evaluates the performance of advanced Ni- Cr- Mo alloys 59 and C- 276 in a simulated sulfur dioxide scrubber environment. Accelerated tests showed that high Ni- Cr- Mo alloys have little tendency to leach metal ions such as chromium, nickel, and molybdenum at different impressed potentials. Scanning electron microscopy was used to examine the morphology of pitting attack.

  7. Sparingly solvating electrolytes for high energy density Lithium–sulfur batteries

    SciTech Connect

    Cheng, Lei; Curtiss, Larry A.; Zavadil, Kevin R.; Gewirth, Andrew A.; Shao, Yuyan; Gallagher, Kevin G.

    2016-07-11

    Moving to lighter and less expensive battery chemistries compared to lithium-ion requires the control of energy storage mechanisms based on chemical transformations rather than intercalation. Lithium sulfur (Li/S) has tremendous theoretical specific energy, but contemporary approaches to control this solution-mediated, precipitation-dissolution chemistry requires using large excesses of electrolyte to fully solubilize the polysulfide intermediate. Achieving reversible electrochemistry under lean electrolyte operation is the only path for Li/S to move beyond niche applications to potentially transformational performance. An emerging topic for Li/S research is the use of sparingly solvating electrolytes and the creation of design rules for discovering new electrolyte systems that fundamentally decouple electrolyte volume from reaction mechanism. Furthermore, this perspective presents an outlook for sparingly solvating electrolytes as the key path forward for longer-lived, high-energy density Li/S batteries including an overview of this promising new concept and some strategies for accomplishing it.

  8. Hierarchical TiO2 spheres as highly efficient polysulfide host for lithium-sulfur batteries

    PubMed Central

    Yang, Zhi-Zheng; Wang, Hui-Yuan; Lu, Lun; Wang, Cheng; Zhong, Xiao-Bin; Wang, Jin-Guo; Jiang, Qi-Chuan

    2016-01-01

    Hierarchical TiO2 micron spheres assembled by nano-plates were prepared through a facile hydrothermal route. Chemical tuning of the TiO2 through hydrogen reduction (H-TiO2) is shown to increase oxygen-vacancy density and thereby modifies the electronic properties. H-TiO2 spheres with a polar surface serve as the surface-bound intermediates for strong polysulfides binding. Under the restricting and recapturing effect, the sulfur cathode could deliver a high reversible capacity of 928.1 mA h g−1 after 50 charge-discharge cycles at a current density of 200 mA g−1. The H-TiO2 additive developed here is practical for restricting and recapturing the polysulfide from the electrolyte. PMID:26965058

  9. Sparingly Solvating Electrolytes for High Energy Density Lithium-Sulfur Batteries

    SciTech Connect

    Cheng, Lei; Curtiss, Larry A.; Zavadil, Kevin R.; Gewirth, Andrew A.; Shao, Yuyan; Gallagher, Kevin

    2016-07-11

    Moving to lighter and less expensive battery chemistries compared to lithium-ion requires the control of energy storage mechanisms based on chemical transformations rather than intercalation. Lithium sulfur (Li/S) has tremendous theoretical specific energy, but contemporary approaches to control this solution-mediated, precipitation-dissolution chemistry requires using large excesses of electrolyte to fully solubilize the polysulfide intermediate. Achieving reversible electrochemistry under lean electrolyte operation is the only path for Li/S to move beyond niche applications to potentially transformational performance. An emerging topic for Li/S research is the use of sparingly solvating electrolytes and the creation of design rules for discovering new electrolyte systems that fundamentally decouple electrolyte volume from reaction mechanism. This perspective presents an outlook for sparingly solvating electrolytes as the key path forward for longer-lived, high-energy density Li/S batteries including an overview of this promising new concept and some strategies for accomplishing it.

  10. High-rate lithium-sulfur batteries promoted by reduced graphene oxide coating.

    PubMed

    Li, Nianwu; Zheng, Mingbo; Lu, Hongling; Hu, Zibo; Shen, Chenfei; Chang, Xiaofeng; Ji, Guangbin; Cao, Jieming; Shi, Yi

    2012-04-28

    Lithium-sulfur batteries have a poor rate performance and low cycle stability due to the shuttling loss of intermediate lithium polysulfides. To address this issue, a carbon-sulfur nanocomposite coated with reduced graphene oxide was designed to confine the polysulfides.

  11. Relapsed acute promyelocytic leukemia in a hemodialysis-dependent patient treated with arsenic trioxide: a case report

    PubMed Central

    2012-01-01

    Introduction In the relapsed setting, arsenic trioxide remains the backbone of treatment. Scant literature exists regarding treatment of relapsed acute promyelocytic leukemia in patients with renal failure. To the best of our knowledge we are the first to report a safe and effective means of treatment for relapsed acute promyelocytic leukemia in the setting of advanced renal failure, employing titration of arsenic trioxide based on clinical parameters rather than arsenic trioxide levels. Case presentation A 33-year-old Caucasian man with a history of acute promyelocytic leukemia in remission for 3 years, as well as dialysis-dependent chronic renal failure secondary to a solitary kidney and focal segmental glomerulosclerosis and human immunodeficiency virus infection, receiving highly active antiretroviral therapy presented to our hospital with bone marrow biopsy-confirmed relapsed acute promyelocytic leukemia. Arsenic trioxide was begun at a low dose with dose escalation based only on side effect profile monitoring and not laboratory testing for induction as well as maintenance without undue toxicity. Our patient achieved and remains in complete hematologic and molecular remission as of this writing. Conclusion Arsenic trioxide can be used safely and effectively to treat acute promyelocytic leukemia in patients with advanced renal failure using careful monitoring of side effects rather than blood levels of arsenic to guide therapeutic dosing. PMID:23078653

  12. Cross-stacked carbon nanotube film as an additional built-in current collector and adsorption layer for high-performance lithium sulfur batteries

    NASA Astrophysics Data System (ADS)

    Sun, Li; Kong, Weibang; Li, Mengya; Wu, Hengcai; Jiang, Kaili; Li, Qunqing; Zhang, Yihe; Wang, Jiaping; Fan, Shoushan

    2016-02-01

    Cross-stacked carbon nanotube (CNT) film is proposed as an additional built-in current collector and adsorption layer in sulfur cathodes for advanced lithium sulfur (Li-S) batteries. On one hand, the CNT film with high conductivity, microstructural rough surface, high flexibility and mechanical durability retains stable and direct electronic contact with the sulfur cathode materials, therefore decreasing internal resistivity and suppressing polarization of the cathode. On the other hand, the highly porous structure and the high surface area of the CNT film provide abundant adsorption points to support and confine sulfur cathode materials, alleviate their aggregation and promote high sulfur utilization. Moreover, the lightweight and compact structure of the CNT film adds no extra weight or volume to the sulfur cathode, benefitting the improvement of energy densities. Based on these characteristics, the sulfur cathode with a 100-layer cross-stacked CNT film presents excellent rate performances with capacities of 986, 922 and 874 mAh g-1 at cycling rates of 0.2C, 0.5C and 1C for sulfur loading of 60 wt%, corresponding to an improvement of 52%, 109% and 146% compared to that without a CNT film. Promising cycling performances are also demonstrated, offering great potential for scaled-up production of sulfur cathodes for Li-S batteries.

  13. A highly stable anode, carbon-free, catalyst support based on tungsten trioxide nanoclusters for proton-exchange membrane fuel cells.

    PubMed

    Dou, Meiling; Hou, Ming; Zhang, Huabing; Li, Guangfu; Lu, Wangting; Wei, Zidong; Shao, Zhigang; Yi, Baolian

    2012-05-01

    Durability is an important issue in proton-exchange membrane fuel cells (PEMFCs). One of the major challenges lies in the degradation caused by the oxidation of the carbon support under high anode potentials (under fuel starvation conditions). Herein, we report highly stable, carbon-free, WO(3) nanoclusters as catalyst supports. The WO(3) nanoclusters are synthesized through a hard template method and characterized by means of electron microscopy and electrochemical analysis. The electrochemical studies show that the WO(3) nanoclusters have excellent electrochemical stability under a high potential (1.6 V for 10 h) compared to Vulcan XC-72. Pt nanoparticles supported on these nanoclusters exhibit high and stable electrocatalytic activity for the oxidation of hydrogen. The catalyst shows negligible loss in electrochemically active surface area (ECA) after an accelerated durability test, whereas the ECA of the Pt nanoparticles immobilized on conventional carbon decreases significantly after the same oxidation condition. Therefore, Pt/WO(3) could be considered as a promising alternative anode catalyst for PEMFCs.

  14. Screening hydrolysis products of sulfur mustard agents by high-performance liquid chromatography with inductively coupled plasma mass spectrometry detection.

    PubMed

    Kroening, Karolin K; Richardson, Douglas D; Afton, Scott; Caruso, Joseph A

    2009-04-01

    Sulfur mustard (HD), bis(2-chloroethyl)sulfide, is one of a class of mustard agents which are chemical warfare agents. The main chemical warfare hydrolysis degradation products of sulfur mustards are: thiodiglycol, bis(2-hydroxyethylthio)methane, 1,2-bis(2-hydroxyethylthio)ethane, 1,3-bis(2-hydroxyethylthio)propane, and 1,4-bis(2-hydroxyethylthio)butane. The aim of this study is to identify these five hydrolysis degradation products utilizing reversed-phase high-performance liquid chromatography coupled with inductively coupled plasma mass spectrometry (ICP-MS) for element-specific sulfur detection using a collision/reaction cell and electrospray ionization mass spectrometry to confirm the identification. To date, this is the first study utilizing ICP-MS with (32)S element-specific detection for the analysis of vesicant chemical warfare agent degradation products.

  15. Conventional superconductivity at 203 kelvin at high pressures in the sulfur hydride system.

    PubMed

    Drozdov, A P; Eremets, M I; Troyan, I A; Ksenofontov, V; Shylin, S I

    2015-09-03

    A superconductor is a material that can conduct electricity without resistance below a superconducting transition temperature, Tc. The highest Tc that has been achieved to date is in the copper oxide system: 133 kelvin at ambient pressure and 164 kelvin at high pressures. As the nature of superconductivity in these materials is still not fully understood (they are not conventional superconductors), the prospects for achieving still higher transition temperatures by this route are not clear. In contrast, the Bardeen-Cooper-Schrieffer theory of conventional superconductivity gives a guide for achieving high Tc with no theoretical upper bound--all that is needed is a favourable combination of high-frequency phonons, strong electron-phonon coupling, and a high density of states. These conditions can in principle be fulfilled for metallic hydrogen and covalent compounds dominated by hydrogen, as hydrogen atoms provide the necessary high-frequency phonon modes as well as the strong electron-phonon coupling. Numerous calculations support this idea and have predicted transition temperatures in the range 50-235 kelvin for many hydrides, but only a moderate Tc of 17 kelvin has been observed experimentally. Here we investigate sulfur hydride, where a Tc of 80 kelvin has been predicted. We find that this system transforms to a metal at a pressure of approximately 90 gigapascals. On cooling, we see signatures of superconductivity: a sharp drop of the resistivity to zero and a decrease of the transition temperature with magnetic field, with magnetic susceptibility measurements confirming a Tc of 203 kelvin. Moreover, a pronounced isotope shift of Tc in sulfur deuteride is suggestive of an electron-phonon mechanism of superconductivity that is consistent with the Bardeen-Cooper-Schrieffer scenario. We argue that the phase responsible for high-Tc superconductivity in this system is likely to be H3S, formed from H2S by decomposition under pressure. These findings raise hope for the

  16. Conventional superconductivity at 203 kelvin at high pressures in the sulfur hydride system

    NASA Astrophysics Data System (ADS)

    Drozdov, A. P.; Eremets, M. I.; Troyan, I. A.; Ksenofontov, V.; Shylin, S. I.

    2015-09-01

    A superconductor is a material that can conduct electricity without resistance below a superconducting transition temperature, Tc. The highest Tc that has been achieved to date is in the copper oxide system: 133 kelvin at ambient pressure and 164 kelvin at high pressures. As the nature of superconductivity in these materials is still not fully understood (they are not conventional superconductors), the prospects for achieving still higher transition temperatures by this route are not clear. In contrast, the Bardeen-Cooper-Schrieffer theory of conventional superconductivity gives a guide for achieving high Tc with no theoretical upper bound--all that is needed is a favourable combination of high-frequency phonons, strong electron-phonon coupling, and a high density of states. These conditions can in principle be fulfilled for metallic hydrogen and covalent compounds dominated by hydrogen, as hydrogen atoms provide the necessary high-frequency phonon modes as well as the strong electron-phonon coupling. Numerous calculations support this idea and have predicted transition temperatures in the range 50-235 kelvin for many hydrides, but only a moderate Tc of 17 kelvin has been observed experimentally. Here we investigate sulfur hydride, where a Tc of 80 kelvin has been predicted. We find that this system transforms to a metal at a pressure of approximately 90 gigapascals. On cooling, we see signatures of superconductivity: a sharp drop of the resistivity to zero and a decrease of the transition temperature with magnetic field, with magnetic susceptibility measurements confirming a Tc of 203 kelvin. Moreover, a pronounced isotope shift of Tc in sulfur deuteride is suggestive of an electron-phonon mechanism of superconductivity that is consistent with the Bardeen-Cooper-Schrieffer scenario. We argue that the phase responsible for high-Tc superconductivity in this system is likely to be H3S, formed from H2S by decomposition under pressure. These findings raise hope for the

  17. THE EFFECT OF COFIRING HIGH-SULFUR COAL WITH MUNICIPAL WASTE ON FORMATION OF POLYCHLORINATED DIBENZODIOXIN AND POLYCHLORINATED DIBENZOFURAN

    EPA Science Inventory

    The effect of co-firing minor amounts (5-10 wt%) of high sulfur coal with municipal refuse-derived fuel (RDF) on emissions of polychlorinated dibenzo-p-dioxin (PCDD) and polychlorinated dibenzofuran (PCDF) was studied under a range of operating conditions. Through use of 2x facto...

  18. Potential of elemental sulfur fertigation to reduce high soil pH for production of highbush blueberry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Blueberry is adapted to acidic soil conditions but is often planted in high pH soils by adding elemental sulfur (S) prior to planting. Two pot experiments were carried out in a glasshouse to determine the potential of applying elemental S by fertigation through a drip irrigation system. In the first...

  19. Radiative lifetimes and transition probabilities for electric-dipole delta n equals zero transitions in highly stripped sulfur ions

    NASA Technical Reports Server (NTRS)

    Pegg, D. J.; Elston, S. B.; Griffin, P. M.; Forester, J. P.; Thoe, R. S.; Peterson, R. S.; Sellin, I. A.; Hayden, H. C.

    1976-01-01

    The beam-foil time-of-flight method has been used to investigate radiative lifetimes and transition rates involving allowed intrashell transitions within the L shell of highly ionized sulfur. The results for these transitions, which can be particularly correlation-sensitive, are compared with current calculations based upon multiconfigurational models.

  20. High performance lithium-sulfur batteries for storing pulsed energy generated by triboelectric nanogenerators.

    PubMed

    Song, Weixing; Wang, Chao; Gan, Baoheng; Liu, Mengmeng; Zhu, Jianxiong; Nan, Xihui; Chen, Ning; Sun, Chunwen; Chen, Jitao

    2017-03-27

    Storing pulsed energy harvested by triboelectric nanogenerators (TENGs) from ambient mechanical motion is an important technology for obtaining sustainable, low-cost, and green power. Here, we introduce high-energy-density Li-S batteries with excellent performance for storing pulsed output from TENGs. The sandwich-structured sulfur composites with multi-walled carbon nanotubes and polypyrrole serve as cathode materials that suppress the shuttle effect of polysulfides and thus preserve the structural stability of the cathode during Li-ion insertion and extraction. The charging time and energy storage efficiency of the Li-S batteries are directly affected by the rotation rates of the TENGs. The average storage efficiency of the batteries for pulsed output from TENGs can exceed 80% and even reach 93% at low discharge currents. The Li-S batteries also show excellent rate performance for storing pulsed energy at a high discharge current rate of 5 C. The high storage efficiency and excellent rate capability and cyclability demonstrate the feasibility of storing and exploiting pulsed energy provided by TENGs and the potential of Li-S batteries with high energy storage efficiency for storing pulsed energy harvested by TENGs.

  1. Effect of potassium salts in rats adapted to an acidogenic high-sulfur amino acid diet.

    PubMed

    Sabboh, Houda; Horcajada, Marie-Noëlle; Coxam, Véronique; Tressol, Jean-Claude; Besson, Catherine; Rémésy, Christian; Demigné, Christian

    2005-08-01

    Low-grade metabolic acidosis, consecutive to excessive catabolism of sulfur amino acids and a high dietary Na:K ratio, is a common feature of Western food habits. This metabolic alteration may exert various adverse physiological effects, especially on bone, muscle and kidneys. To assess the actual effects of various K salts, a model of the Westernised diet has been developed in rats: slight protein excess (20 % casein); cations provided as non-alkalinising salts; high Na:K ratio. This diet resulted in acidic urine (pH 5.5) together with a high rate of divalent cation excretion in urine, especially Mg. Compared with controls, K supplementation as KCl accentuated Ca excretion, whereas potassium bicarbonate or malate reduced Mg and Ca excretion and alkalinised urine pH (up to 8). In parallel, citraturia was strongly increased, together with 2-ketoglutarate excretion, by potassium bicarbonate or malate in the diet. Basal sulfate excretion, in the range of 1 mmol/d, was slightly enhanced in rats fed the potassium malate diet. The present model of low-grade metabolic acidosis indicates that potassium malate may be as effective as KHCO3 to counteract urine acidification, to limit divalent cation excretion and to ensure high citrate concentration in urine.

  2. Tungsten - Tungsten Trioxide Electrodes for the Long-term Monitoring of Corrosion Processes in Highly Alkaline Media and Concrete-based Materials.

    PubMed

    Kolar, Mitja; Doliška, Aleš; Svegl, Franc; Kalcher, Kurt

    2010-12-01

    The determination of pH in highly alkaline solutions and concrete materials is extremely important for monitoring or predicting the corrosion processes of reinforced concrete structures and to follow the hydration process of Portland cement, fly-ash, micro silica and other materials used in concrete manufacturing. The corrosion of reinforced concrete structures and the hydration of pozzolanic materials are long-term processes, which means, that appropriate durable, and resilient pH electrodes are needed, for direct implantation regarding solid concrete bodies. The purpose of this work was to characterise the potentiometric and surface properties of tungsten electrodes after exposure to extreme alkaline solutions. The tungsten wire surface was activated at 800 °C for 30 min within an oxygen flow. The formation of homogenous and compact multiple layers of WO3 crystals was observed using X-ray diffraction and scanning electron microscopy. X-ray diffraction of those tungsten electrodes exposed to saturated calcium hydroxide solution or the pore-water of cement-based materials during 10 months, indicated partly dissolved WO3. Two new compounds appeared on the electrodes surfaces; pure tungsten and CaWO4. The presence of tungsten was affecting any potentiometric response in acidic pH region (2-5) but in pH 5-12 region the response still remained linear with a slope of 42 ± 2 mV/pH unit. The W/WO3 electrode was suitable for the long-term monitoring of corrosion processes in concrete-based materials according to the pH changes as it has stable and repeatable responses to alkaline solutions (pH > 12). All the tested interferring ions had no significant influence on electrode potential. The W/WO3 electrode is simple, robust, inexpensive, and temperature resistant and can be applied in potentiometric titrations as well as in batch and flow-injection analysis. The prepared electrode is a highly promising pH sensor for the monitoring of pH changes in highly alkaline capillary

  3. Effect of sulfur on rolling contact fatigue life of high-manganese precipitation-hardening austenitic steel

    SciTech Connect

    Haruna, Y.; Yamamoto, A.; Tsubakino, H.

    1998-10-05

    For mechanical components used in high magnetic flux such as bearings and shafts that undergo cyclic stress, materials require low permeability with high strength, hardness, appropriate machinability, and good fatigue properties. Although it is implied that low permeability and machinability will be achieved by a selection of sulfurized austenitic ({gamma}) steel grades, effect of manganese sulfide (MnS) on fatigue properties of such grades especially for bearing applications is not clarified. For high-carbon chromium bearing steels, the effect of MnS on rolling contact fatigue life of the steels containing sulfur less than 0.03% are discussed. In these studies, the effect of MnS is not clearly determined whether it is beneficial or harmful to contact fatigue lives of the steels. However, effect of MnS under higher sulfur content, i.e., 0.10%, on the fatigue properties of {gamma} steel has not been studied. In this paper, the effect of sulfur on rolling contact fatigue properties of vanadium added {gamma} steel, 10Cr-6Ni-8Mn-1.6V-0.6C, was investigated focusing on microstructural change in connection with MnS particles.

  4. A Facile Bottom-Up Approach to Construct Hybrid Flexible Cathode Scaffold for High-Performance Lithium-Sulfur Batteries.

    PubMed

    Ghosh, Arnab; Manjunatha, Revanasiddappa; Kumar, Rajat; Mitra, Sagar

    2016-12-14

    Lithium-sulfur batteries mostly suffer from the low utilization of sulfur, poor cycle life, and low rate performances. The prime factors that affect the performance are enormous volume change of the electrode, soluble intermediate product formation, poor electronic and ionic conductivity of S, and end discharge products (i.e., Li2S2 and Li2S). The attractive way to mitigate these challenges underlying in the fabrication of a sulfur nanocomposite electrode consisting of different nanoparticles with distinct properties of lithium storage capability, mechanical reinforcement, and ionic as well as electronic conductivity leading to a mechanically robust and mixed conductive (ionic and electronic conductive) sulfur electrode. Herein, we report a novel bottom-up approach to synthesize a unique freestanding, flexible cathode scaffold made of porous reduced graphene oxide, nanosized sulfur, and Mn3O4 nanoparticles, and all are three-dimensionally interconnected to each other by hybrid polyaniline/sodium alginate (PANI-SA) matrix to serve individual purposes. A capacity of 1098 mAh g(-1) is achieved against lithium after 200 cycles at a current rate of 2 A g(-1) with 97.6% of initial capacity at a same current rate, suggesting the extreme stability and cycling performance of such electrode. Interestingly, with the higher current density of 5 A g(-1), the composite electrode exhibited an initial capacity of 1015 mA h g(-1) and retained 71% of the original capacity after 500 cycles. The in situ Raman study confirms the polysulfide absorption capability of Mn3O4. This work provides a new strategy to design a mechanically robust, mixed conductive nanocomposite electrode for high-performance lithium-sulfur batteries and a strategy that can be used to develop flexible large power storage devices.

  5. Extraordinarily High Leaf Selenium to Sulfur Ratios Define ‘Se-accumulator’ Plants

    PubMed Central

    White, Philip J.; Bowen, Helen C.; Marshall, Bruce; Broadley, Martin R.

    2007-01-01

    Background and Aims Selenium (Se) and sulfur (S) exhibit similar chemical properties. In flowering plants (angiosperms) selenate and sulfate are acquired and assimilated by common transport and metabolic pathways. It is hypothesized that most angiosperm species show little or no discrimination in the accumulation of Se and S in leaves when their roots are supplied a mixture of selenate and sulfate, but some, termed Se-accumulator plants, selectively accumulate Se in preference to S under these conditions. Methods This paper surveys Se and S accumulation in leaves of 39 angiosperm species, chosen to represent the range of plant Se accumulation phenotypes, grown hydroponically under identical conditions. Results The data show that, when supplied a mixture of selenate and sulfate: (1) plant species differ in both their leaf Se ([Se]leaf) and leaf S ([S]leaf) concentrations; (2) most angiosperms show little discrimination for the accumulation of Se and S in their leaves and, in non-accumulator plants, [Se]leaf and [S]leaf are highly correlated; (3) [Se]leaf in Se-accumulator plants is significantly greater than in other angiosperms, but [S]leaf, although high, is within the range expected for angiosperms in general; and (4) the Se/S quotient in leaves of Se-accumulator plants is significantly higher than in leaves of other angiosperms. Conclusion The traits of extraordinarily high [Se]leaf and leaf Se/S quotients define the distinct elemental composition of Se-accumulator plants. PMID:17525099

  6. Characterization of fly ash from low-sulfur and high-sulfur coal sources: Partitioning of carbon and trace elements with particle size

    USGS Publications Warehouse

    Hower, J.C.; Trimble, A.S.; Eble, C.F.; Palmer, C.A.; Kolker, A.

    1999-01-01

    Fly ash samples were collected in November and December of 1994, from generating units at a Kentucky power station using high- and low-sulfur feed coals. The samples are part of a two-year study of the coal and coal combustion byproducts from the power station. The ashes were wet screened at 100, 200, 325, and 500 mesh (150, 75, 42, and 25 ??m, respectively). The size fractions were then dried, weighed, split for petrographic and chemical analysis, and analyzed for ash yield and carbon content. The low-sulfur "heavy side" and "light side" ashes each have a similar size distribution in the November samples. In contrast, the December fly ashes showed the trend observed in later months, the light-side ash being finer (over 20 % more ash in the -500 mesh [-25 ??m] fraction) than the heavy-side ash. Carbon tended to be concentrated in the coarse fractions in the December samples. The dominance of the -325 mesh (-42 ??m) fractions in the overall size analysis implies, though, that carbon in the fine sizes may be an important consideration in the utilization of the fly ash. Element partitioning follows several patterns. Volatile elements, such as Zn and As, are enriched in the finer sizes, particularly in fly ashes collected at cooler, light-side electrostatic precipitator (ESP) temperatures. The latter trend is a function of precipitation at the cooler-ESP temperatures and of increasing concentration with the increased surface area of the finest fraction. Mercury concentrations are higher in high-carbon fly ashes, suggesting Hg adsorption on the fly ash carbon. Ni and Cr are associated, in part, with the spinel minerals in the fly ash. Copyright ?? 1999 Taylor & Francis.

  7. Ethanol Reduced Molybdenum Trioxide for Li-ion Capacitors

    DOE PAGES

    Li, Tianqi; Beidaghi, Majid; Xiao, Xu; ...

    2016-05-06

    Orthorhombic molybdenum trioxide (α-MoO3) is a layered oxide with promising performance as electrode material for Li-ion capacitors. In this study, we show that expansion of the interlayer spacing (by ~0.32 Å) of the structure along the b-axis, introduced by partial reduction of α-MoO3 and formation of MoO3-x (x=0.06–0.43), results in enhanced diffusion of Li ions. Binder-free hybrid electrodes made of MoO3-x nanobelts and carbon nanotubes show excellent electrical conductivity. The combination of increased interlayer spacing and enhanced electron transport leads to high gravimetric and volumetric capacitances of about 420 F/g or F/cm3 and excellent cycle life of binder-free MoO3-x electrodes.

  8. Reactions of ethyl diazoacetate catalyzed by methylrhenium trioxide

    SciTech Connect

    Zhu, Z.; Espenson, H.

    1995-11-03

    Methylrhenium trioxide (CH{sub 3}ReO{sub 3} or MTO) has found wise use in catalysis, including the epoxidation and metathesis of olefins, aldehyde olefination, and oxygen transfer. Extensive reports have now appeared in the area of MTO-catalyzed substrate oxidations with hydrogen peroxide. Certain catalytic applications of MTO for organic reactions that do not utilize peroxide have now been realized. In particular, a catalytic amount of MTO with ethyl diazoacetate (EDA) will convert aromatic imines to aziridines and convert aldehydes and ketones to epoxides. The aziridine preparation proceeds in high yields under anaerobic conditions more conveniently than with existing methods. Compounds with a three-membered heterocyclic ring can be obtained with the EDA/MTO catalytic system. Aromatic imines undergo cycloaddition reactions to give aziridines under mild conditions.

  9. Ethanol Reduced Molybdenum Trioxide for Li-ion Capacitors

    SciTech Connect

    Li, Tianqi; Beidaghi, Majid; Xiao, Xu; Huang, Liang; Hu, Zhimi; Sun, Wanmei; Chen, Xun; Gogotsi, Yury G.; Zhou, Jun

    2016-05-06

    Orthorhombic molybdenum trioxide (α-MoO3) is a layered oxide with promising performance as electrode material for Li-ion capacitors. In this study, we show that expansion of the interlayer spacing (by ~0.32 Å) of the structure along the b-axis, introduced by partial reduction of α-MoO3 and formation of MoO3-x (x=0.06–0.43), results in enhanced diffusion of Li ions. Binder-free hybrid electrodes made of MoO3-x nanobelts and carbon nanotubes show excellent electrical conductivity. The combination of increased interlayer spacing and enhanced electron transport leads to high gravimetric and volumetric capacitances of about 420 F/g or F/cm3 and excellent cycle life of binder-free MoO3-x electrodes.

  10. Sulfur transformations in pilot-scale constructed wetland treating high sulfate-containing contaminated groundwater: a stable isotope assessment.

    PubMed

    Wu, Shubiao; Jeschke, Christina; Dong, Renjie; Paschke, Heidrun; Kuschk, Peter; Knöller, Kay

    2011-12-15

    Current understanding of the dynamics of sulfur compounds inside constructed wetlands is still insufficient to allow a full description of processes involved in sulfur cycling. Experiments in a pilot-scale horizontal subsurface flow constructed wetland treating high sulfate-containing contaminated groundwater were carried out. Application of stable isotope approach combined with hydro-chemical investigations was performed to evaluate the sulfur transformations. In general, under inflow concentration of about 283 mg/L sulfate sulfur, sulfate removal was found to be about 21% with a specific removal rate of 1.75 g/m(2)·d. The presence of sulfide and elemental sulfur in pore water about 17.3 mg/L and 8.5 mg/L, respectively, indicated simultaneously bacterial sulfate reduction and re-oxidation. 70% of the removed sulfate was calculated to be immobilized inside the wetland bed. The significant enrichment of (34)S and (18)O in dissolved sulfate (δ(34)S up to 16‰, compared to average of 5.9‰ in the inflow, and δ(18)O up to 13‰, compared to average of 6.9‰ in the inflow) was observed clearly correlated to the decrease of sulfate loads along the flow path through experimental wetland bed. This enrichment also demonstrated the occurrence of bacterial sulfate reduction as well as demonstrated by the presence of sulfide in the pore water. Moreover, the integral approach shows that bacterial sulfate reduction is not the sole process controlling the isotopic composition of dissolved sulfate in the pore water. The calculated apparent enrichment factor (ɛ = -22‰) for sulfur isotopes from the δ(34)S vs. sulfate mass loss was significantly smaller than required to produce the observed difference in δ(34)S between sulfate and sulfide. It indicated some potential processes superimposing bacterial sulfate reduction, such as direct re-oxidation of sulfide to sulfate by oxygen released from plant roots and/or bacterial disproportionation of elemental sulfur. Furthermore

  11. Organic transformations catalyzed by methylrhenium trioxide

    SciTech Connect

    Zhu, Zuolin

    1995-10-06

    Methylrhenium trioxide (MTO), CH3ReO3, was first prepared in 1979. MTO forms stable or unstable adducts with electron-rich ligands, such as amines (quinuclidine, 1,4-diazabicyclo-octane, pyridine, aniline, 2,2'-bipyridine), alkynes, olefins, 1,2-diols, catechols, hydrogen peroxide, water, thiophenols, 1,2-dithiols, triphenylphosphine, 2-aminophenols, 2-aminothiophenols, 8-hydroxyquinoline and halides (Cl-, Br-, I-). After coordination, different further reactions will occur for different reagents. Reactions described in this report include the dehydration of alcohols, direct amination of alcohols, activation of hydrogen peroxide, oxygen transfer, and decomposition of ethyl diazoacetate.

  12. HYBRID SULFUR CYCLE FLOWSHEETS FOR HYDROGEN PRODUCTION USING HIGH-TEMPERATURE GAS-COOLED REACTORS

    SciTech Connect

    Gorensek, M.

    2011-07-06

    Two hybrid sulfur (HyS) cycle process flowsheets intended for use with high-temperature gas-cooled reactors (HTGRs) are presented. The flowsheets were developed for the Next Generation Nuclear Plant (NGNP) program, and couple a proton exchange membrane (PEM) electrolyzer for the SO2-depolarized electrolysis step with a silicon carbide bayonet reactor for the high-temperature decomposition step. One presumes an HTGR reactor outlet temperature (ROT) of 950 C, the other 750 C. Performance was improved (over earlier flowsheets) by assuming that use of a more acid-tolerant PEM, like acid-doped poly[2,2'-(m-phenylene)-5,5'-bibenzimidazole] (PBI), instead of Nafion{reg_sign}, would allow higher anolyte acid concentrations. Lower ROT was accommodated by adding a direct contact exchange/quench column upstream from the bayonet reactor and dropping the decomposition pressure. Aspen Plus was used to develop material and energy balances. A net thermal efficiency of 44.0% to 47.6%, higher heating value basis is projected for the 950 C case, dropping to 39.9% for the 750 C case.

  13. The thickness of 18-MEA on an ultra-high-sulfur protein surface by molecular modeling.

    PubMed

    Natarajan, Upendra; Robbins, Clarence

    2010-01-01

    The use of computational chemistry techniques via molecular modeling software provides additional support to the hair surface model by Negri et al. (1) and refines the thickness of the 18-methyl eicosanoic acid (18-MEA) lipid layer attached by thioester linkages to an ultra-high-sulfur protein (UHSP) at 1.08 ± 0.2 nm. This value compares favorably to the thickness of that same layer from X-ray photoelectron spectroscopy (XPS) measurements by Ward et al. (2) at 1.00 ± 0.5 nm on Soxhlet-extracted wool. The model clarifies that the results of Ward et al. via XPS are not an artifact of high vacuum (3), but due to relaxation of the 18-MEA structure onto the wool protein backbone as suggested by Zahn et al. (4). In this molecular model, 18-MEA is attached to beta sheets of an UHSP via thioester linkages as suggested by Negri et al. in their 1993 study (15) and by earlier work by Evans et al. (5). The beta sheets of this model provide an intersheet spacing of 0.7 nm and a beta sheet density of 1.42 g/cm(3) compared with Allworden membrane fractions that varied from 1.39 to 1.54 g/cm(3) (6).

  14. A trilayer separator with dual function for high performance lithium-sulfur batteries

    NASA Astrophysics Data System (ADS)

    Song, Rensheng; Fang, Ruopian; Wen, Lei; Shi, Ying; Wang, Shaogang; Li, Feng

    2016-01-01

    In this article, we propose a trilayer graphene/polypropylene/Al2O3 (GPA) separator with dual function for high performance lithium-sulfur (Li-S) batteries. Graphene is coated on one side of polypropylene (PP) separator, which functions as a conductive layer and an electrolyte reservoir that allows for rapid electron and ion transport. Then Al2O3 particles are coated on the other side to further enhance thermal stability and safety of the graphene coated polypropylene (GCP) separator, which are touched with lithium metal anode in the Li-S battery. The GPA separator shows good thermal stability after heating at 157 °C for 10 min while both GCP and PP separators showing an obvious shrinkage about 10%. The initial discharge specific capacity of Li-S coin cell with a GPA separator could reach 1067.7 mAh g-1 at 0.2C. After 100 discharge/charge cycles, it can still deliver a reversible capacity of as high as 804.4 mAh g-1 with 75% capacity retention. The pouch cells further confirm that the trilayer design has great promise towards practical applications.

  15. Impact of free calcium oxide content of fly ash on dust and sulfur dioxide emissions in a lignite-fired power plant

    SciTech Connect

    Dimitrios Sotiropoulos; Andreas Georgakopoulos; Nestoras Kolovos

    2005-07-01

    Emitted pollutants from the Agios Dimitrios lignite-fired power plant in northern Greece show a very strong linear correlation with the free calcium oxide content of the lignite ash. Dust (fly ash) emissions are positively correlated to free calcium oxide content, whereas sulfur dioxide (SO{sub 2}) emissions are negatively correlated. As a result, at present, the Agios Dimitrios Power Plant operates very strictly within the legislative limits on atmospheric particulate emission. In the study reported, the factors to be considered in assessing the impact of lignite combustion on the environment are presented and evaluated statistically. The ash appears to have a remarkable SO{sub 2} natural dry scrubbing capability when the free calcium oxide content ranges between 4 and 7%. Precipitator operating problems attributable to high ash resistivity can be overcome by injecting sulfur trioxide to reduce the ash resistivity, with, of course, a probable increase in operating costs. 27 refs., 7 figs., 1 tab.

  16. Highly-flexible 3D Li2S/graphene cathode for high-performance lithium sulfur batteries

    NASA Astrophysics Data System (ADS)

    He, Jiarui; Chen, Yuanfu; Lv, Weiqiang; Wen, Kechun; Li, Pingjian; Qi, Fei; Wang, Zegao; Zhang, Wanli; Li, Yanrong; Qin, Wu; He, Weidong

    2016-09-01

    Three-dimensional Li2S/graphene hierarchical architecture (3DLG) is synthesized with a facile infiltration method. Highly-crystalline Li2S nanoparticles are deposited homogenously into three-dimensional graphene foam (3DGF) network grown by chemical vapor deposition (CVD), resulting in 3DLG with high surface area, porosity, flexibility and conductivity. The 3DLG is employed as flexible, free-standing and binder-free cathode without metallic current collectors or conducting additives. Due to the unique structure, the 3DLG exhibits a high discharge capacity of 894.7 mAh g-1 at 0.1 C, a high capacity retention of 87.7% after 300 cycles at 0.2 C, and the high-rate capacity up to 4 C reaches 598.6 mAh g-1. The cyclic performance is record-breaking compared to the previous reports on free-standing graphene-Li2S cathodes. Flexible lithium-sulfur batteries based on the high-capacity 3DLG cathode have promising application potentials in flexible electronics, electrical vehicles, etc.

  17. Elemental Sulfur and Molybdenum Disulfide Composites for Li-S Batteries with Long Cycle Life and High-Rate Capability.

    PubMed

    Dirlam, Philip T; Park, Jungjin; Simmonds, Adam G; Domanik, Kenneth; Arrington, Clay B; Schaefer, Jennifer L; Oleshko, Vladimir P; Kleine, Tristan S; Char, Kookheon; Glass, Richard S; Soles, Christopher L; Kim, Chunjoong; Pinna, Nicola; Sung, Yung-Eun; Pyun, Jeffrey

    2016-06-01

    The practical implementation of Li-S technology has been hindered by short cycle life and poor rate capability owing to deleterious effects resulting from the varied solubilities of different Li polysulfide redox products. Here, we report the preparation and utilization of composites with a sulfur-rich matrix and molybdenum disulfide (MoS2) particulate inclusions as Li-S cathode materials with the capability to mitigate the dissolution of the Li polysulfide redox products via the MoS2 inclusions acting as "polysulfide anchors". In situ composite formation was completed via a facile, one-pot method with commercially available starting materials. The composites were afforded by first dispersing MoS2 directly in liquid elemental sulfur (S8) with sequential polymerization of the sulfur phase via thermal ring opening polymerization or copolymerization via inverse vulcanization. For the practical utility of this system to be highlighted, it was demonstrated that the composite formation methodology was amenable to larger scale processes with composites easily prepared in 100 g batches. Cathodes fabricated with the high sulfur content composites as the active material afforded Li-S cells that exhibited extended cycle lifetimes of up to 1000 cycles with low capacity decay (0.07% per cycle) and demonstrated exceptional rate capability with the delivery of reversible capacity up to 500 mAh/g at 5 C.

  18. Pie-like electrode design for high-energy density lithium-sulfur batteries

    NASA Astrophysics Data System (ADS)

    Li, Zhen; Zhang, Jin Tao; Chen, Yu Ming; Li, Ju; Lou, Xiong Wen (David)

    2015-11-01

    Owing to the overwhelming advantage in energy density, lithium-sulfur (Li-S) battery is a promising next-generation electrochemical energy storage system. Despite many efforts in pursuing long cycle life, relatively little emphasis has been placed on increasing the areal energy density. Herein, we have designed and developed a `pie' structured electrode, which provides an excellent balance between gravimetric and areal energy densities. Combining lotus root-like multichannel carbon nanofibers `filling' and amino-functionalized graphene `crust', the free-standing paper electrode (S mass loading: 3.6 mg cm-2) delivers high specific capacity of 1,314 mAh g-1 (4.7 mAh cm-2) at 0.1 C (0.6 mA cm-2) accompanied with good cycling stability. Moreover, the areal capacity can be further boosted to more than 8 mAh cm-2 by stacking three layers of paper electrodes with S mass loading of 10.8 mg cm-2.

  19. Pie-like electrode design for high-energy density lithium-sulfur batteries.

    PubMed

    Li, Zhen; Zhang, Jin Tao; Chen, Yu Ming; Li, Ju; Lou, Xiong Wen David

    2015-11-26

    Owing to the overwhelming advantage in energy density, lithium-sulfur (Li-S) battery is a promising next-generation electrochemical energy storage system. Despite many efforts in pursuing long cycle life, relatively little emphasis has been placed on increasing the areal energy density. Herein, we have designed and developed a 'pie' structured electrode, which provides an excellent balance between gravimetric and areal energy densities. Combining lotus root-like multichannel carbon nanofibers 'filling' and amino-functionalized graphene 'crust', the free-standing paper electrode (S mass loading: 3.6 mg cm(-2)) delivers high specific capacity of 1,314 mAh g(-1) (4.7 mAh cm(-2)) at 0.1 C (0.6 mA cm(-2)) accompanied with good cycling stability. Moreover, the areal capacity can be further boosted to more than 8 mAh cm(-2) by stacking three layers of paper electrodes with S mass loading of 10.8 mg cm(-2).

  20. Sparingly solvating electrolytes for high energy density Lithium–sulfur batteries

    DOE PAGES

    Cheng, Lei; Curtiss, Larry A.; Zavadil, Kevin R.; ...

    2016-07-11

    Moving to lighter and less expensive battery chemistries compared to lithium-ion requires the control of energy storage mechanisms based on chemical transformations rather than intercalation. Lithium sulfur (Li/S) has tremendous theoretical specific energy, but contemporary approaches to control this solution-mediated, precipitation-dissolution chemistry requires using large excesses of electrolyte to fully solubilize the polysulfide intermediate. Achieving reversible electrochemistry under lean electrolyte operation is the only path for Li/S to move beyond niche applications to potentially transformational performance. An emerging topic for Li/S research is the use of sparingly solvating electrolytes and the creation of design rules for discovering new electrolyte systemsmore » that fundamentally decouple electrolyte volume from reaction mechanism. Furthermore, this perspective presents an outlook for sparingly solvating electrolytes as the key path forward for longer-lived, high-energy density Li/S batteries including an overview of this promising new concept and some strategies for accomplishing it.« less

  1. A review of atomic layer deposition providing high performance lithium sulfur batteries

    NASA Astrophysics Data System (ADS)

    Yan, Bo; Li, Xifei; Bai, Zhimin; Song, Xiaosheng; Xiong, Dongbin; Zhao, Mengli; Li, Dejun; Lu, Shigang

    2017-01-01

    With the significant obstacles that have been conquered in lithium-sulfur (Li-S) batteries, it is urgent to impel accelerating development of room-temperature Li-S batteries with high energy density and long-term stability. In view of the unique solid-liquid-solid conversion processes of Li-S batteries, however, designing effective strategies to address the insulativity and volume effect of cathode, shuttle of soluble polysulfides, and/or safety hazard of Li metal anode has been challenging. An atomic layer deposition (ALD) is a representative thin film technology with exceptional capabilities in developing atomic-precisely conformal films. It has been demonstrated to be a promise strategy of solving emerging issues in advanced electrical energy storage (EES) devices via the surface modification and/or the fabrication of complex nanostructured materials. In this review, the recent developments and significances on how ALD improves the performance of Li-S batteries were discussed in detail. Significant attention mainly focused on the various strategies with the use of ALD to refine the electrochemical interfaces and cell configurations. Furthermore, the novel opportunities and perspective associated with ALD for future research directions were summarized. This review may boost the development and application of advanced Li-S batteries using ALD.

  2. Pie-like electrode design for high-energy density lithium–sulfur batteries

    PubMed Central

    Li, Zhen; Zhang, Jin Tao; Chen, Yu Ming; Li, Ju; Lou, Xiong Wen (David)

    2015-01-01

    Owing to the overwhelming advantage in energy density, lithium–sulfur (Li–S) battery is a promising next-generation electrochemical energy storage system. Despite many efforts in pursuing long cycle life, relatively little emphasis has been placed on increasing the areal energy density. Herein, we have designed and developed a ‘pie' structured electrode, which provides an excellent balance between gravimetric and areal energy densities. Combining lotus root-like multichannel carbon nanofibers ‘filling' and amino-functionalized graphene ‘crust', the free-standing paper electrode (S mass loading: 3.6 mg cm−2) delivers high specific capacity of 1,314 mAh g−1 (4.7 mAh cm−2) at 0.1 C (0.6 mA cm−2) accompanied with good cycling stability. Moreover, the areal capacity can be further boosted to more than 8 mAh cm−2 by stacking three layers of paper electrodes with S mass loading of 10.8 mg cm−2. PMID:26608228

  3. Compact, DC-electrical biased sulfur dioxide sensing elements for use at high temperatures

    SciTech Connect

    West, David L; Montgomery, Fred C; Armstrong, Beth L

    2012-01-01

    Fabrication and operation of sensing elements for the detection of sulfur dioxide (SO_2) at high temperature (800 900 ^oC) is reported. The sensing elements consisted of three (two oxide and one Pt) electrodes on yttria-stabilized zirconia substrates. To operate the elements, a DC current (typically about 0.1 mA) is driven between two of the electrodes and the voltage between one of these electrodes and the third electrode is used as the sensing signal. These sensing elements respond very strongly to SO_2, for example 2 ppm_V of SO_2 in a background of 7 vol% O_2, balance N_2 was found to produce a >10% change in the sensing signal, which could be easily detected. Sensing elements fabricated to be nominally identical were shown to yield qualitatively identical sensing behavior, and temperature, oxygen content, and flow were all found to strongly impact sensing performance. The impact of interferents, such as NO_x and CO, was evaluated and found to be relatively small in comparison to the SO_2 response. The sensing response, over a 1 month period, was very stable, with the ratio of the average change in sensing signal over one day to the average sensing signal magnitude being about 0.1%.

  4. Sulfur dioxide derivatives modulation of high-threshold calcium currents in rat dorsal root ganglion neurons.

    PubMed

    Du, Zhengqing; Meng, Ziqiang

    2006-09-11

    This study addressed the effect of sulfur dioxide (SO(2)) derivatives on high-voltage-activated calcium currents (HVA-I(Ca)) in somatic membrane of freshly isolated rat dorsal root ganglion (DRG) neurons by using the whole-cell configuration of patch-clamp technique. High-threshold Ca(2+) channels are highly expressed in small dorsal root ganglion neurons. SO(2) derivatives increased the amplitudes of calcium currents in a concentration-dependent and voltage-dependent manner. The 50% enhancement concentrations (EC(50)) of SO(2) derivatives on HVA-I(Ca) was about 0.4 microM. In addition, SO(2) derivatives significantly shifted the activation and inactivation curve in the depolarizing direction. Parameters for the fit of a Boltzmann equation to mean values for the activation were V(1/2)=-17.9+/-1.3 mV before and -12.5+/-1.1 mV after application 0.5 microM SO(2) derivatives 2 min (P<0.05). The half inactivation of HVA-I(Ca) was shifted 9.7 mV to positive direction (P<0.05). Furthermore, SO(2) derivatives significantly prolonged the slow constant of inactivation, slowed the fast recovery but markedly accelerated the slow recovery of HVA-I(Ca) from inactivation. From HP of -60 mV 0.5 microM SO(2) derivatives increased the amplitude of HVA-I(Ca) with a depolarizing voltage step to -10 mV about 54.0% in small DRG neurons but 33.3% in large DRG neurons. These results indicated a possible correlation between the change of calcium channels and SO(2) inhalation toxicity, which might cause periphery neurons abnormal regulation of nociceptive transmission via calcium channels.

  5. Sulfur impregnated N, P co-doped hierarchical porous carbon as cathode for high performance Li-S batteries

    NASA Astrophysics Data System (ADS)

    Cai, Junjie; Wu, Chun; Zhu, Ying; Zhang, Kaili; Shen, Pei Kang

    2017-02-01

    A nitrogen and phosphorus co-doped hierarchical porous carbon (N, P-HPC) were fabricated by simply pyrolysis of polyaniline aerogels in the presence of phytic acid and subsequently activation treatment by KOH. The as-prepared N, P-HPC with a highly interconnected network structure and possesses a large surface area and pore volume is very favor in the impregnation of sulfur. Moreover, simultaneously introduced nitrogen and phosphorous into the carbon could create more active sites than the mono-doped carbons, the synergistic effects of dual activation of carbon atoms induced stronger chemical adsorption ability. Benefiting from the advantages of suitable hierarchical porosity, high conductivity, fast ion transportation, physical and chemical adsorption of the N, P-HPC, the Sulfur/N, P-HPC composite exhibits high initial discharge capacity of 1116 mAh g-1 at 0.1 C (1 C = 1675 mA g-1, based on sulfur content) and high rate capability of 550 mAh g-1 at 2C, as well as excellent long term cycling stability at a current rate of 1 C with only 0.058% capacity decay per cycle for over 500 cycles. Such a high capacity and stability suggests that the novel cathode have alluring prospect for Li-S batteries.

  6. Novel sulfur-oxidizing streamers thriving in perennial cold saline springs of the Canadian high Arctic.

    PubMed

    Niederberger, Thomas D; Perreault, Nancy N; Lawrence, John R; Nadeau, Jay L; Mielke, Randall E; Greer, Charles W; Andersen, Dale T; Whyte, Lyle G

    2009-03-01

    The perennial springs at Gypsum Hill (GH) and Colour Peak (CP), situated at nearly 80 degrees N on Axel Heiberg Island in the Canadian high Arctic, are one of the few known examples of cold springs in thick permafrost on Earth. The springs emanate from deep saline aquifers and discharge cold anoxic brines rich in both sulfide and sulfate. Grey-coloured microbial streamers form during the winter months in snow-covered regions of the GH spring run-off channels (-1.3 degrees C to 6.9 degrees C, approximately 7.5% NaCl, 0-20 p.p.m. dissolved sulfide, 1 p.p.m. dissolved oxygen) but disappear during the Arctic summer. Culture- and molecular-based analyses of the 16S rRNA gene (FISH, DGGE and clone libraries) indicated that the streamers were uniquely dominated by chemolithoautotrophic sulfur-oxidizing Thiomicrospira species. The streamers oxidized both sulfide and thiosulfate and fixed CO(2) under in situ conditions and a Thiomicrospira strain isolated from the streamers also actively oxidized sulfide and thiosulfate and fixed CO(2) under cold, saline conditions. Overall, the snow-covered spring channels appear to represent a unique polar saline microhabitat that protects and allows Thiomicrospira streamers to form and flourish via chemolithoautrophic, phototrophic-independent metabolism in a high Arctic winter environment characterized by air temperatures commonly below -40 degrees C and with an annual average air temperature of -15 degrees C. These results broaden our knowledge of the physical and chemical boundaries that define life on Earth and have astrobiological implications for the possibility of life existing under similar Martian conditions.

  7. High-Resolution Infrared Spectroscopy of Carbon-Sulfur Chains: I. C_3S and SC_7S

    NASA Astrophysics Data System (ADS)

    Dudek, John B.; Salomon, Thomas; Thorwirth, Sven

    2016-06-01

    In the course of a recent 5 μm high-resolution infrared study of laser ablation products from carbon-sulfur targets, we have reinvestigated the ν_1 vibrational mode of the linear C_3S molecule complementing significantly the pioneering data originally reported by Takano and coworkers. In addition, located within the R-branch of the C_3S vibrational mode, a weak new band is observed which exhibits very tight line spacing. On the basis of high-level quantum-chemical calculations, this feature is attributed to the linear SC_7S species, which stands for the first gas-phase spectroscopic detection of this heavy carbon-sulfur chain. S. Takano, J. Tang, and S. Saito 1996, J. Mol. Spectrosc. 178, 194

  8. Sulfur dioxide oxidation induced mechanistic branching and particle formation during the ozonolysis of β-pinene and 2-butene.

    PubMed

    Carlsson, Philip T M; Keunecke, Claudia; Krüger, Bastian C; Maaß, Mona-C; Zeuch, Thomas

    2012-12-05

    Recent studies have suggested that the reaction of stabilised Criegee Intermediates (CIs) with sulfur dioxide (SO(2)), leading to the formation of a carbonyl compound and sulfur trioxide, is a relevant atmospheric source of sulfuric acid. Here, the significance of this pathway has been examined by studying the formation of gas phase products and aerosol during the ozonolysis of β-pinene and 2-butene in the presence of SO(2) in the pressure range of 10 to 1000 mbar. For β-pinene at atmospheric pressure, the addition of SO(2) suppresses the formation of the secondary ozonide and leads to highly increased nopinone yields. A complete consumption of SO(2) is observed at initial SO(2) concentrations below the yield of stabilised CIs. In experiments using 2-butene a significant consumption of SO(2) and additional formation of acetaldehyde are observed at 1 bar. A consistent kinetic simulation of the experimental findings is possible when a fast CI + SO(2) reaction rate in the range of recent direct measurements [Welz et al., Science, 2012, 335, 204] is used. For 2-butene the addition of SO(2) drastically increases the observed aerosol yields at higher pressures. Below 60 mbar the SO(2) oxidation induced particle formation becomes inefficient pointing to the critical role of collisional stabilisation for sulfuric acid controlled nucleation at low pressures.

  9. Sulfur removal from high-sulfur Illinois coal by low-temperature perchloroethylene (PCE) extraction. [Quarterly] technical report, March 1, 1993--May 31, 1993

    SciTech Connect

    Chou, M.I.M.; Buchanan, D.H.; Stucki, J.W.

    1993-09-01

    The purposes of this project are: to independently confirm and possibly to improve the organic sulfur removal from Illinois coals with the PCE process developed by the Midwest Ore Processing Co. (MWOPC), to verify the forms-of-sulfur determination using the ASTM method for evaluation of the PCE process, and to develop a dechlorination procedure to remove excess PCE from the PCE-treated coal. The objectives for the second year are: to verify the possible effects of PCE treatment on coal-derived FeS{sub 2}, FeSO{sub 4}, and Fe{sub 2}(SO{sub 4}){sub 3} on ASTM coal analysis, to investigate the behavior of sulfur during oxidation and PCE desulfurization using the isotopically signatured coal sample, to investigate the effects of conditions and/or reagents on the oxidation of the organic-sulfur-model compounds, to evaluate the extended oxidation condition on the organic sulfur removal by PCE desulfurization, and to study other innovative pretreatment processes for the removal of organic sulfur from coal under mild conditions.

  10. Sulfur removal from high-sulfur Illinois coal by low-temperature perchloroethylene (PCE) extraction. Technical report, December 1, 1992--February 28, 1993

    SciTech Connect

    Chou, M.I.M.; Lytle, J.M.; Ruch, R.R.; Kruse, C.W.; Chaven, C.; Hackley, K.C.; Hughes, R.E.; Harvey, R.D.; Buchanan, D.H.; Stucki, J.W.; Huffman, G.; Huggins, F.E.; Ho, K.K.

    1993-05-01

    The purpose of this project are to independently confirm and possibly to improve the organic sulfur removal from Illinois coals with the PCE process developed by the Midwest Ore Processing Co.(MWOPC), to verify the forms-of-sulfur determination using the ASTM method for evaluation of the PCE process, and to develop a dechlorination procedure to remove excess PCE from the PCE-treated coal. The objectives for year-2 study are to verify the possible effect of PCE treatment on coal-derived FeS{sub 2}, FeSO{sub 4}, and Fe{sub 2}(SO{sub 4}){sub 3} on ASTM coal analysis, to investigate the behavior of sulfur during oxidation and PCE desulfurization using the isotopically signatured coal sample to investigate the proprietary reagent on the oxidation of the organic sulfur model compounds with and without additives, to evaluate this new oxidation on the organic sulfur removal by PCE desulfurization, and to study other innovative pretreatment processes for the removal of organic sulfur from coal under mild conditions. Oxidation study on the organosulfur model compounds alone was completed in first quarter. The oxidation reactions were repeated on the organosulfur model compounds with the presence of hydrocarbon additives. These additives are known to easily produce hydroperoxides during air oxidation. Analysis of the reaction products is in progress.

  11. Bioprocessing of High-sulfur Crudes Via Appliaction of Critical Fluid Biocatalysis

    SciTech Connect

    Ginosar, Daniel Michael; Bala, Greg Alan; Anderson, Raymond Paul; Fox, Sandra Lynn; Stanescue, Marina A.

    2002-05-01

    This experimental research project investigated protein-based biocatalysis in supercritical fluid solvents as an integrated process approach to catalyze the removal of sulfur atoms from crude oils and fuels. The work focused on the oxidation of model sulfur-containing compounds in supercritical reaction media and included three major tasks: microbiological induction experiments, proteincatalyzed biooxidation in supercritical solvents, and a work-in-kind cooperative research and development agreement (CRADA). This work demonstrated that the biooxidation reaction could be improved by an order-of-magnitude by carrying out the reaction in emulsions in supercritical fluids.

  12. Economics of utilization of high sulfur coal resources - an integrated market approach

    USGS Publications Warehouse

    Bhagwat, S.B.

    1993-01-01

    Before the Clean Air Act Amendments of 1990, coal policies - especially coal research policies - were geared to find a solution to the sulfur emission problem. However, technologies to reduce sulfur emissions cannot be tailored for a single coal. A technology that will clean Illinois coal to compliance levels will do the same, or nearly the same, for most other types of coal. This paper will discuss an integrated approach to the analysis of the future of coals from different regions in the United States and its implications for coal-related policies by government and industry.

  13. Catalyst for the reduction of sulfur dioxide to elemental sulfur

    DOEpatents

    Jin, Yun; Yu, Qiquan; Chang, Shih-Ger

    1996-01-01

    The inventive catalysts allow for the reduction of sulfur dioxide to elemental sulfur in smokestack scrubber environments. The catalysts have a very high sulfur yield of over 90% and space velocity of 10,000 h.sup.-1. They also have the capacity to convert waste gases generated during the initial conversion into elemental sulfur. The catalysts have inexpensive components, and are inexpensive to produce. The net impact of the invention is to make this technology practically available to industrial applications.

  14. Polycyclic aromatic hydrocarbons (PAHs) around tea processing industries using high-sulfur coals.

    PubMed

    Saikia, Jyotilima; Khare, Puja; Saikia, Prasenjit; Saikia, Binoy K

    2016-09-27

    In the present investigation, the concentrations of polycyclic aromatic hydrocarbons (PAHs) associated with PM2.5, PM10 and dust particles emitted from two tea processing industrial units were studied that uses high-sulfur coal as their energy source. A total of 16 PAHs (viz. naphthalene (Nap), acenaphthene (Ace), acenaphthylene (Acen), phenanthrene (Phe), fluorene (Flu), anthracene (Ant), fluoranthene (Fluo), pyrene (Pyr), benz[a]anthracene (BaA), chrysene (Chry), benzo[b]fluoranthene (BbF), benzo[k]fluoranthene (BkF), benzo[a]pyrene (BaP), dibenz[a,h]anthracene (DBahA), indeno[1,2,3-cd]pyrene (IP) and benzo[ghi]perylene (BghiP) were measured. The total PAH concentration was found to be 94.7 ng/m(3) (∑4 PAHs) in the PM10 particle, 32.5 (∑12 PAHs) in PM2.5 and 1.08 ng/m(3) (∑6 PAHs) in the dust sample from site A. In site B, the sum of the PAHs in the PM2.5, PM10 and dust samples are found to be 154.4 ng/m(3) (∑7 PAHs), 165 ng/m(3) (∑3 PAHs) and 1.27 ng/m(3) (∑6 PAHs), respectively. Hybrid Single Particle Lagrangian Integrated Trajectory model study revealed the contribution of local or long-range transport of aerosol sources. Along with the coal combustion activities in the study sites, other sources such as biomass burning and vehicular emission may contribute to the PAHs in the aerosol samples.

  15. A scalable hybrid separator for a high performance lithium-sulfur battery.

    PubMed

    Wang, Lina; Liu, Jingyuan; Haller, Servane; Wang, Yonggang; Xia, Yongyao

    2015-04-25

    A newly designed hybrid separator composed of a glassy fiber paper and a microporous membrane is effectively integrated into a Li-S battery. Superior cell performance up to 500 cycles is achieved even with commercially available pristine sulfur as cathode material. This fascinating study demonstrates a largely restrained polysulfides shuttle process toward practical Li-S battery application.

  16. Zeolites Remove Sulfur From Fuels

    NASA Technical Reports Server (NTRS)

    Voecks, Gerald E.; Sharma, Pramod K.

    1991-01-01

    Zeolites remove substantial amounts of sulfur compounds from diesel fuel under relatively mild conditions - atmospheric pressure below 300 degrees C. Extracts up to 60 percent of sulfur content of high-sulfur fuel. Applicable to petroleum refineries, natural-gas processors, electric powerplants, and chemical-processing plants. Method simpler and uses considerably lower pressure than current industrial method, hydro-desulfurization. Yields cleaner emissions from combustion of petroleum fuels, and protects catalysts from poisoning by sulfur.

  17. Can MTA be: Miracle trioxide aggregate?

    PubMed Central

    Naik, Reshma M; Pudakalkatti, Pushpa S; Hattarki, Sanjeevini A

    2014-01-01

    Mineral trioxide aggregate (MTA) has been used for more than 10 years in the dental community and has often been thought of as a material of choice for the endodontist. The dental pulp is closely related to periodontal tissues through apical foramina, accessory canals, and dentinal tubules. Due to this interrelationship, pulpal diseases may influence periodontal health and periodontal infections may affect pulpal integrity. It is estimated that pulpal and periodontal problems are responsible for more than 50% of tooth mortality. Thus, these associations recommend an interdisciplinary approach. MTA appears to exhibit significant results even in periodontal procedures as it is the first restorative material that consistently allows for over-growth of cementum and may facilitate periodontal tissue regeneration. Thus, in the present review, an attempt is made to discuss the clinical applications of MTA as an interdisciplinary approach. PMID:24744536

  18. Mineral trioxide aggregate apexification: A novel approach

    PubMed Central

    Purra, Aamir Rashid; Ahangar, Fayaz Ahmed; Chadgal, Sachin; Farooq, Riyaz

    2016-01-01

    The treatment of choice for necrotic teeth with immature root is apexification, which is induction of apical closure to produce more favorable conditions for conventional root canal filling. The most commonly advocated medicament is calcium hydroxide although recently considerable interest has been expressed in the use of mineral trioxide aggregate (MTA). MTA offers the option of a two-visit apexification procedure so that the fragile tooth can be restored immediately. However, difficulty in placing the material in the wide apical area requires the use of an apical matrix. Materials such as collagen, calcium sulfate, and hydroxyapatite have been used for this purpose. This article describes the use of resorbable suture material to form the apical matrix which offers many advantages over the contemporary materials. PMID:27563191

  19. Arsenic Trioxide Negatively Affects Echinococcus granulosus

    PubMed Central

    Wang, Bo; Wang, Zhuo; Li, Fangfang; Xing, Guoqiang; Peng, Xinyu; Zhang, Shijie

    2015-01-01

    Spillage of cyst contents during surgery is the major cause of recurrences of hydatidosis, also called cystic echinococcosis (CE). Currently, many scolicidal agents are used for inactivation of the cyst contents. However, due to complications in the use of those agents, new and more-effective treatment options are urgently needed. The aim of this study was to investigate the in vitro efficacy of arsenic trioxide (ATO) against Echinococcus granulosus protoscolices. Protoscolices of E. granulosus were incubated in vitro with 2, 4, 6, and 8 μmol/liter ATO; viability of protoscolices was assessed daily by microscopic observation of movements and 0.1% eosin staining. A small sample from each culture was processed for scanning and transmission electron microscopy. ATO demonstrated a potent ability to kill protoscolices, suggesting that ATO may represent a new strategy in treating hydatid cyst echinococcosis. However, the in vivo efficacy and possible side effects of ATO need to be explored. PMID:26324279

  20. Comparison of radiation shielding ratios of nano-sized bismuth trioxide and molybdenum

    NASA Astrophysics Data System (ADS)

    Cho, J. H.; Kim, M. S.; Rhim, J. D.

    2015-07-01

    In this study, radiation shielding fibers using non-hazardous nano-sized bismuth trioxide and molybdenum instead of lead were developed and evaluated. Among the elements with high densities and atomic numbers, non-hazardous elements such as bismuth trioxide and molybdenum were chosen as a shielding element. Then, bismuth trioxide (Bi2O3) with average particle size 1-500 µm was ball milled for 10 min to produce a powdered form of nanoparticles with average particle size of 10-100 nm. Bismuth trioxide nanoparticles were dispersed to make a colloidal suspension, followed by spreading and hardening onto one or two sides of fabric, to create the radiation shielding fabric. The thicknesses of the shielding sheets using nano-sized bismuth and molybdenum were 0.4 and 0.7 mm. According to the lead equivalent test of X-ray shielding products suggested by KS, the equivalent dose was measured, followed by calculation of the shielding rate. The shielding rate of bismuth with 0.4 mm thickness and at 50 kVp was 90.5%, which is comparable to lead of 0.082 mm thickness. The shielding rate of molybdenum was 51.89%%, which is comparable to lead of 0.034 mm. At a thickness of 0.7 mm, the shielding rate of bismuth was 98.73%, equivalent to 0.101 mm Pb, whereas the shielding rate of molybdenum was 74.68%, equivalent to 0.045 mm Pb. In conclusion, the radiation shielding fibers using nano-sized bismuth developed in this study are capable of reducing radiation exposure by X-ray and its low-dose scatter ray.

  1. Final Report - Management of High Sulfur HLW, VSL-13R2920-1, Rev. 0, dated 10/31/2013

    SciTech Connect

    Kruger, Albert A.; Gan, H.; Pegg, I. L.; Feng, Z.; Gan, H; Joseph, I.; Matlack, K. S.

    2013-11-13

    The present report describes results from a series of small-scale crucible tests to determine the extent of corrosion associated with sulfur containing HLW glasses and to develop a glass composition for a sulfur-rich HLW waste stream, which was then subjected to small-scale melter testing to determine the maximum acceptable sulfate loadings. In the present work, a new glass formulation was developed and tested for a projected Hanford HLW composition with sulfate concentrations high enough to limit waste loading. Testing was then performed on the DM10 melter system at successively higher waste loadings to determine the maximum waste loading without the formation of a separate sulfate salt phase. Small scale corrosion testing was also conducted using the glass developed in the present work, the glass developed in the initial phase of this work [26], and a high iron composition, all at maximum sulfur concentrations determined from melter testing, in order to assess the extent of Inconel 690 and MA758 corrosion at elevated sulfate contents.

  2. Synthesis of Bi2S3 with different sulfur content by conventional high temperature solid state solvothermal route

    NASA Astrophysics Data System (ADS)

    Solanki, S. I.; Patel, I. B.; Shah, N. M.

    2014-04-01

    Bismuth sulfide (Bi2S3) is a binary chalcogenide compound material belonging to V-VI group of semiconductors. Because of its direct band gap of 1.3 eV and high figure of merit (ZT) value, it is widely used as a thermo electronic-cooling material based on the Peltier effect. The electrical and optical property of Bi2S3 material is strongly dependent on stoichiometric composition, defect chemistry and structure. In this study, we have synthesized Bi2Sx (x = 3.15, 3.30, 3.45) compound material with different sulfur content by conventional high temperature solid state solvothermal reaction of bismuth and sulfur. X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDXS) analysis of synthesized compound materials were carried out to observe crystallinity, surface morphology and composition of elements in the compound. The optical analysis revealed that energy band gap decreases with increase of sulfur content.

  3. Molecular characterization of phytoplankton dissolved organic matter (DOM) and sulfur components using high resolution Orbitrap mass spectrometry.

    PubMed

    Mangal, Vaughn; Stock, Naomi L; Guéguen, Celine

    2016-03-01

    Orbitrap high resolution mass spectrometry (HRMS) with electrospray ionization in both positive and negative polarity was conducted on Suwannee River fulvic acid (SRFA), Pony Lake fulvic acid (PLFA) standards, and dissolved organic matter (DOM) released by freshwater phytoplankton (Scenedesmus obliquus, Euglena mutabilis, and Euglena gracilis). Three-dimensional van Krevelen diagrams expressing various oxygenation states of sulfur molecules and abundance plots of sulfur-containing species were constructed. Orbitrap HRMS analysis of SRFA found a high density of peaks in the lignin region (77 %) and low density of protein material (6.53 %), whereas for PLFA, 25 % of the total peaks were lignin related compared to 56 % of peaks in protein regions, comparable with other HRMS studies. Phytoplankton-derived DOM of S. obliquus, E. mutabilis, and E. gracilis was dominated by protein molecules at respective percentages of 36, 46, and 49 %, and is consistent with previous experiments examining phytoplankton-derived DOM composition. The normalized percentage of SO-containing compounds was determined among the three phytoplankton to be 56 % for Scenedesmus, 54 % for E. mutabilis, and 47 % for E. gracilis, suggesting variation between sulfur content in phytoplankton-derived DOM and differences in metal binding capacities. These results suggest the level of resolution by Orbitrap mass spectrometry is sufficient for preliminary characterization of phytoplankton DOM at an affordable cost relative to other HRMS techniques.

  4. ADVANCED SULFUR CONTROL CONCEPTS

    SciTech Connect

    Apostolos A. Nikolopoulos; Santosh K. Gangwal; William J. McMichael; Jeffrey W. Portzer

    2003-01-01

    Conventional sulfur removal in integrated gasification combined cycle (IGCC) power plants involves numerous steps: COS (carbonyl sulfide) hydrolysis, amine scrubbing/regeneration, Claus process, and tail-gas treatment. Advanced sulfur removal in IGCC systems involves typically the use of zinc oxide-based sorbents. The sulfides sorbent is regenerated using dilute air to produce a dilute SO{sub 2} (sulfur dioxide) tail gas. Under previous contracts the highly effective first generation Direct Sulfur Recovery Process (DSRP) for catalytic reduction of this SO{sub 2} tail gas to elemental sulfur was developed. This process is currently undergoing field-testing. In this project, advanced concepts were evaluated to reduce the number of unit operations in sulfur removal and recovery. Substantial effort was directed towards developing sorbents that could be directly regenerated to elemental sulfur in an Advanced Hot Gas Process (AHGP). Development of this process has been described in detail in Appendices A-F. RTI began the development of the Single-step Sulfur Recovery Process (SSRP) to eliminate the use of sorbents and multiple reactors in sulfur removal and recovery. This process showed promising preliminary results and thus further process development of AHGP was abandoned in favor of SSRP. The SSRP is a direct Claus process that consists of injecting SO{sub 2} directly into the quenched coal gas from a coal gasifier, and reacting the H{sub 2}S-SO{sub 2} mixture over a selective catalyst to both remove and recover sulfur in a single step. The process is conducted at gasifier pressure and 125 to 160 C. The proposed commercial embodiment of the SSRP involves a liquid phase of molten sulfur with dispersed catalyst in a slurry bubble-column reactor (SBCR).

  5. Electrosprayed molybdenum trioxide aqueous solution and its application in organic photovoltaic cells.

    PubMed

    Suzuki, Katsumi; Fukuda, Takeshi; Liao, Yingjie

    2014-01-01

    A molybdenum trioxide thin film with smooth surface and uniform thickness was successfully achieved by an electrospray deposition method using an aqueous solution with a drastically low concentration of 0.05 wt%. Previous papers demonstrated that an additive solvent technique is useful for depositing the thin film by the electrospray deposition, and the high vapor pressure and a low surface tension of an additive solvent were found to be important factors. As a result, the smooth molybdenum trioxide thin film was obtained when the acetonitrile was used as the additive solvent. Furthermore, the vapor pressure of acetone is much higher than that of aqueous solution, and this indicates that the acetone is easily evaporated after spraying from the glass capillary. By optimizing a concentration of acetone in the molybdenum aqueous solution, a minimum root mean square roughness of the MoO3 thin film became 3.7 nm. In addition, an organic photovoltaic cell was also demonstrated using the molybdenum trioxide as a hole transport layer. Highest photoconversion efficiency was 1.72%, a value comparable to that using conventional thermal evaporation process even though the aqueous solution was used for the solution process. The photovonversion efficiency was not an optimized value, and the higher value can be achieved by optimizing the coating condition of the active layer.

  6. Elemental sulfur recovery process

    DOEpatents

    Flytzani-Stephanopoulos, Maria; Hu, Zhicheng

    1993-01-01

    An improved catalytic reduction process for the direct recovery of elemental sulfur from various SO.sub.2 -containing industrial gas streams. The catalytic process provides combined high activity and selectivity for the reduction of SO.sub.2 to elemental sulfur product with carbon monoxide or other reducing gases. The reaction of sulfur dioxide and reducing gas takes place over certain catalyst formulations based on cerium oxide. The process is a single-stage, catalytic sulfur recovery process in conjunction with regenerators, such as those used in dry, regenerative flue gas desulfurization or other processes, involving direct reduction of the SO.sub.2 in the regenerator off gas stream to elemental sulfur in the presence of a catalyst.

  7. Elemental sulfur recovery process

    DOEpatents

    Flytzani-Stephanopoulos, M.; Zhicheng Hu.

    1993-09-07

    An improved catalytic reduction process for the direct recovery of elemental sulfur from various SO[sub 2]-containing industrial gas streams. The catalytic process provides combined high activity and selectivity for the reduction of SO[sub 2] to elemental sulfur product with carbon monoxide or other reducing gases. The reaction of sulfur dioxide and reducing gas takes place over certain catalyst formulations based on cerium oxide. The process is a single-stage, catalytic sulfur recovery process in conjunction with regenerators, such as those used in dry, regenerative flue gas desulfurization or other processes, involving direct reduction of the SO[sub 2] in the regenerator off gas stream to elemental sulfur in the presence of a catalyst. 4 figures.

  8. Sulfur revisited.

    PubMed

    Lin, A N; Reimer, R J; Carter, D M

    1988-03-01

    Sulfur is a time-honored therapeutic agent useful in a variety of dermatologic disorders. Its keratolytic action is due to formation of hydrogen sulfide through a reaction that depends upon direct interaction between sulfur particles and keratinocytes. The smaller the particle size, the greater the degree of such interaction and the greater the therapeutic efficacy. When applied topically, sulfur induces various histologic changes, including hyperkeratosis, acanthosis, and dilatation of dermal vasculature. One study showed that sulfur was comedogenic when applied onto human and rabbit skin, findings that were not reproduced in other studies. About 1% of topically applied sulfur is systemically absorbed. Adverse effects from topically applied sulfur are uncommon and are mainly limited to the skin. In infants, however, fatal outcome after extensive application has been reported.

  9. Ultrastructural localization of hair keratins, high sulfur keratin-associated proteins and sulfhydryl oxidase in the human hair.

    PubMed

    Alibardi, Lorenzo

    2017-03-01

    Hardening of the human hair shaft during cornification results from the bonding of keratins and keratin-associated proteins. In situ hybridization and light immunocytochemical studies have shown the general distribution of different keratins and some associated proteins but not determined their ultrastructural localization. I report here the localization of hair keratins, two high-sulfur keratin-associated proteins and sulfhydryl oxidase has been studied under the transmission electron microscope in the cornification zone of the human hair. The ultrastructural study on keratin distribution in general confirms previous light microscopic studies. Sulfur-rich KAP1 is mainly cortical but the labeling disappears in fully cornified cortical cells while a diffuse labeling is also present in differentiating cuticle cells. Sulfur-rich K26 immunolocalization is only detected in the exocuticle and endocuticle. Sparse labeling for sulfhydryl oxidase occurs in differentiating cortical cells but is weak and uneven in cuticle cells and absent in medulla and inner root sheath. Labeling disappears in the upper fully cornified cortex and cuticle. The observations indicate that sulfhydryl oxidase and keratin associated proteins are initially produced in the cytoplasm among keratin bundles accumulating in cortical and cuticle cells but these proteins undergo changes during the following cornification that alter the epitopes tagged by the antibodies.

  10. Determination of sulfur in bovine serum albumin and L-cysteine using high-resolution continuum source molecular absorption spectrometry of the CS molecule

    NASA Astrophysics Data System (ADS)

    Andrade-Carpente, Eva; Peña-Vázquez, Elena; Bermejo-Barrera, Pilar

    2016-08-01

    In this study, the content of sulfur in bovine serum albumin and L-cysteine was determined using high-resolution continuum source molecular absorption spectrometry of the CS molecule, generated in a reducing air-acetylene flame. Flame conditions (height above the burner, measurement time) were optimized using a 3.0% (v/v) sulfuric acid solution. A microwave lab station (Ethos Plus MW) was used for the digestion of both compounds. During the digestion step, sulfur was converted to sulfate previous to the determination. Good repeatability (4-10%) and analytical recovery (91-106%) was obtained.

  11. Biosorption and biodegradation of a sulfur dye in high-strength dyeing wastewater by Acidithiobacillus thiooxidans.

    PubMed

    Nguyen, Thai Anh; Fu, Chun-Chieh; Juang, Ruey-Shin

    2016-11-01

    The ability of the bacterial strain Acidithiobacillus thiooxidans to remove sulfur blue 15 (SB15) dye from water samples was examined. This bacterium could not only oxidize sulfur compounds to sulfuric acid but also promote the attachment of the cells to the surface of sulfidic particles, therefore serving as an efficient biosorbent. The biosorption isotherms were better described by the Langmuir equation than by the Freundlich or Dubinin-Radushkevich equation. Also, the biosorption process followed the pseudo-second-order kinetics. At pH 8.3 and SB15 concentrations up to 2000 mg L(-1) in the biomass/mineral salt solution, the dye removal and decolorization were 87.5% and 91.4%, respectively, following the biosorption process. Biodegradation was proposed as a subsequent process for the remaining dye (250-350 mg L(-1)). A central composite design was used to analyze independent variables in the response surface methodology study. Under the optimal conditions (i.e., initial dye concentration of 300 mg L(-1), initial biomass concentration of 1.0 g L(-1), initial pH of 11.7, and yeast extract dose of 60 mg L(-1)), up to 50% of SB15 was removed after 4 days of biodegradation.

  12. AFM as an analysis tool for high-capacity sulfur cathodes for Li–S batteries

    PubMed Central

    Sörgel, Seniz; Costa, Rémi; Carlé, Linus; Galm, Ines; Cañas, Natalia; Pascucci, Brigitta; Friedrich, K Andreas

    2013-01-01

    Summary In this work, material-sensitive atomic force microscopy (AFM) techniques were used to analyse the cathodes of lithium–sulfur batteries. A comparison of their nanoscale electrical, electrochemical, and morphological properties was performed with samples prepared by either suspension-spraying or doctor-blade coating with different binders. Morphological studies of the cathodes before and after the electrochemical tests were performed by using AFM and scanning electron microscopy (SEM). The cathodes that contained polyvinylidene fluoride (PVDF) and were prepared by spray-coating exhibited a superior stability of the morphology and the electric network associated with the capacity and cycling stability of these batteries. A reduction of the conductive area determined by conductive AFM was found to correlate to the battery capacity loss for all cathodes. X-ray diffraction (XRD) measurements of Li2S exposed to ambient air showed that insulating Li2S hydrolyses to insulating LiOH. This validates the significance of electrical ex-situ AFM analysis after cycling. Conductive tapping mode AFM indicated the existence of large carbon-coated sulfur particles. Based on the analytical findings, the first results of an optimized cathode showed a much improved discharge capacity of 800 mA·g(sulfur)−1 after 43 cycles. PMID:24205455

  13. Regional river sulfur runoff

    SciTech Connect

    Husar, R.B.; Husar, J.D.

    1985-01-20

    The water and sulfur runoff data for 54 large river basins were assembled, covering 65% of the nondesert land area of the world. The sulfur concentration ranges from 0.5 mg S/L for the West African rivers Niger and Volta to 100 mg S/L in the Colorado River; the world average is 3.2 mg S/L. The concentrations in central and eastern Europe as well as central and eastern North America exceed 8 mg S/L. The sulfur runoff density is also highest in the river basins over these industrialized regions, exceeding 2 g S/m/sup 2//yr. However, high sulfur runoff density in excess of 3 g S/m/sup 2//yr is also measured over the Pacific islands New Zealand and New Guinea and the archipelagos of Indonesia and the Philippines. The natural background sulfur runoff was estimated by assuming that South America, Africa, Australia, and the Pacific Islands are unperturbed by man and that the average river sulfur concentration is in the range 1--3 mg S/L. Taking these background concentration values, the man-induced sulfur runoff for Europe ranges between 2 and 8 times the natural flow, and over North America, man's contribution ranges between 1 and 5 times the natural runoff. The global sulfur flow from nondesert land to the oceans and the Caspian Sea is estimated as 131 Tg S/yr, of which 46--85 Tg S/yr is attributed to natural causes. The regional river sulfur runoff pattern discussed in this paper does not have enough spatial resolution to be directly applicable to studies of the environmental effects of man-induced sulfur flows. However, it points to the continental-size regions where those perturbations are most evident and to the magnitude of the perturbations as expressed in units of the natural flows.

  14. Regional river sulfur runoff

    NASA Astrophysics Data System (ADS)

    Husar, Rudolf B.; Husar, Janja Djukic

    1985-01-01

    The water and sulfur runoff data for 54 large river basins were assembled, covering 65% of the nondesert land area of the world. The sulfur concentration ranges from 0.5 mg S/L for the West African rivers Niger and Volta to 100 mg S/L in the Colorado River; the world average is 3.2 mg S/L. The concentrations in central and eastern Europe as well as central and eastern North America exceed 8 mg S/L. The sulfur runoff density is also highest in the river basins over these industrialized regions, exceeding 2 g S/m2/yr. However, high sulfur runoff density in excess of 3 g S/m2/yr is also measured over the Pacific islands New Zealand and New Guinea and the archipelagos of Indonesia and the Philippines. The natural background sulfur runoff was estimated by assuming that South America, Africa, Australia, and the Pacific Islands are unperturbed by man and that the average river sulfur concentration is in the range 1-3 mg S/L. Taking these background concentration values, the man-induced sulfur runoff for Europe ranges between 2 and 8 times the natural flow, and over North America, man's contribution ranges between 1 and 5 times the natural runoff. The global sulfur flow from nondesert land to the oceans and the Caspian Sea is estimated as 131 Tg S/yr, of which 46-85 Tg S/yr is attributed to natural causes. The regional river sulfur runoff pattern discussed in this paper does not have enough spatial resolution to be directly applicable to studies of the environmental effects of man-induced sulfur flows. However, it points to the continental-size regions where those perturbations are most evident and to the magnitude of the perturbations as expressed in units of the natural flows.

  15. A Flexible Nanostructured Paper of a Reduced Graphene Oxide-Sulfur Composite for High-Performance Lithium-Sulfur Batteries with Unconventional Configurations.

    PubMed

    Cao, Jun; Chen, Chen; Zhao, Qing; Zhang, Ning; Lu, Qiongqiong; Wang, Xinyu; Niu, Zhiqiang; Chen, Jun

    2016-11-01

    Flexible nanostructured reduced graphene oxide-sulfur (rGO-S) composite films are fabricated by synchronously reducing and assembling GO sheets with S nanoparticles on a metal surface. The nanostructured architecture in such composite films not only provides effective pathways for electron transport, but also suppresses the diffusion of polysulfides. Furthermore, they can serve as the cathodes of flexible Li-S batteries.

  16. Leaching of zinc sulfide by Thiobacillus ferrooxidans: Bacterial oxidation of the sulfur product layer increases the rate of zinc sulfide dissolution at high concentrations of ferrous ions

    SciTech Connect

    Fowler, T.A.; Crundwell, F.K.

    1999-12-01

    This paper reports the results of leaching experiments conducted with and without Thiobacillus ferroxidans at the same conditions in solution. The extent of leaching of ZnS with Bacteria is significantly higher than that without bacteria at high concentrations of ferrous ions. A porous layer of elemental sulfur is present on the surfaces of the chemically leached particles, which no sulfur is present on the surfaces of the bacterially leached particles. The analysis of the data using the shrinking-core model shows that the chemical leaching of ZnS is limited by the diffusion of ferrous ions through the sulfur product layer at high concentrations of ferrous ions. The analysis of the data shows that diffusion through the product layer does not limit the rate of dissolution when bacteria are present. This suggests that the action of T.ferroxidans in oxidizing the sulfur formed on the particle surface is to remove the barrier to diffusion by ferrous ions.

  17. Double-Shelled Nanocages with Cobalt Hydroxide Inner Shell and Layered Double Hydroxides Outer Shell as High-Efficiency Polysulfide Mediator for Lithium-Sulfur Batteries.

    PubMed

    Zhang, Jintao; Hu, Han; Li, Zhen; Lou, Xiong Wen David

    2016-03-14

    Lithium-sulfur (Li-S) batteries have been considered as a promising candidate for next-generation electrochemical energy-storage technologies because of their overwhelming advantages in energy density. Suppression of the polysulfide dissolution while maintaining a high sulfur utilization is the main challenge for Li-S batteries. Here, we have designed and synthesized double-shelled nanocages with two shells of cobalt hydroxide and layered double hydroxides (CH@LDH) as a conceptually new sulfur host for Li-S batteries. Specifically, the hollow CH@LDH polyhedra with complex shell structures not only maximize the advantages of hollow nanostructures for encapsulating a high content of sulfur (75 wt %), but also provide sufficient self-functionalized surfaces for chemically bonding with polysulfides to suppress their outward dissolution. When evaluated as cathode material for Li-S batteries, the CH@LDH/S composite shows a significantly improved electrochemical performance.

  18. Leaching of Zinc Sulfide by Thiobacillus ferrooxidans: Bacterial Oxidation of the Sulfur Product Layer Increases the Rate of Zinc Sulfide Dissolution at High Concentrations of Ferrous Ions

    PubMed Central

    Fowler, T. A.; Crundwell, F. K.

    1999-01-01

    This paper reports the results of leaching experiments conducted with and without Thiobacillus ferrooxidans at the same conditions in solution. The extent of leaching of ZnS with bacteria is significantly higher than that without bacteria at high concentrations of ferrous ions. A porous layer of elemental sulfur is present on the surfaces of the chemically leached particles, while no sulfur is present on the surfaces of the bacterially leached particles. The analysis of the data using the shrinking-core model shows that the chemical leaching of ZnS is limited by the diffusion of ferrous ions through the sulfur product layer at high concentrations of ferrous ions. The analysis of the data shows that diffusion through the product layer does not limit the rate of dissolution when bacteria are present. This suggests that the action of T. ferrooxidans in oxidizing the sulfur formed on the particle surface is to remove the barrier to diffusion by ferrous ions. PMID:10583978

  19. [Mineral trioxide aggregate (MTA) a success story in apical surgery].

    PubMed

    von Arx, Thomas

    2016-01-01

    The objective of apical surgery is to retain teeth with persistent apical pathosis following orthograde root canal treatment if endodontic non-surgical revision is difficult or associated with risks, or is even declined by the patient. Since the most frequent cause of recurrent apical disease is bacterial reinfection from the (remaining) root canal system, the bacteria-tight root-end filling is the most important step in apical surgery. In the early 1990s, mineral trioxide aggregate (MTA) was developed at the Loma Linda University in California/USA. Preclinical studies clearly showed that MTA has a high sealing capability, a good material stability and an excellent biocompatbility. Multiple experimental studies in animals highlighted the mild tissue reactions observed adjacent to this material. Furthermore, histological analysis of the periapical regions demonstrated a frequent deposition of new cementum not only onto the resection plane (cut dentinal surface), but also directly onto MTA. For these reasons, MTA is considered a bioactive material. In 1997 MTA was cleared for clinical use in patients. Multiple prospective clinical and randomized studies have documented high and constant success rates of MTA-treated teeth in apical surgery. A recently published longitudinal study showed that MTA-treated teeth remained stable over five years; hence the high healed rates documented after one year are maintained during long-term observation.

  20. Organic Matter Sulfurization in the Cariaco Water Column Revealed by High-Sensitivity and Compound-Specific d34S Analyses.

    NASA Astrophysics Data System (ADS)

    Raven, M. R.; Sessions, A. L.; Adkins, J. F.; Thunell, R.

    2015-12-01

    Organic matter burial in marine sediments is a major process in the global carbon cycle, and enhanced organic matter burial is often associated with periods of global climatic and ecological change. Still, we have only a limited understanding of the processes that drive enhanced OM burial during oxygen-deficient conditions. Abiotic OM sulfurization has the potential to enhance the preservation of OM, but for this process to be significant it must compete with heterotrophic remineralization, most of which occurs before sinking particles reach the sea floor. We investigate the sources of sulfur to sinking particles in a modern marine basin using samples from the CARIACO fixed sediment trap time-series, applying recently developed methods for d34S analysis of small (≥20 nmol) sulfur pools and individual volatile organosulfur compounds. Relative to expectations for planktonic biomass, we find that sinking particles are both sulfur-rich and 34S-depleted. Higher apparent fluxes of 34S-depleted organic sulfur are associated with high OM export from the surface ocean, low terrestrial inputs, and high concentrations of both elemental S and the dominant non-polar organosulfur compound, C20 thiophene. We conclude that OM sulfurization is occurring in particles sinking through the Cariaco water column on timescales of days or less. Depending on the frequency of high OM export events, we estimate that this rapid sulfurization delivers roughly half of the total organic S present at 5 cm depth in underlying sediments. Accordingly, many OM-rich deposits in the geologic record may represent the products of water column sulfurization. This process provides a strong mechanistic feedback between oxygen deficiency and OM preservation.

  1. Sulfuric Acid on Europa

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Frozen sulfuric acid on Jupiter's moon Europa is depicted in this image produced from data gathered by NASA's Galileo spacecraft. The brightest areas, where the yellow is most intense, represent regions of high frozen sulfuric acid concentration. Sulfuric acid is found in battery acid and in Earth's acid rain.

    This image is based on data gathered by Galileo's near infrared mapping spectrometer.

    Europa's leading hemisphere is toward the bottom right, and there are enhanced concentrations of sulfuric acid in the trailing side of Europa (the upper left side of the image). This is the face of Europa that is struck by sulfur ions coming from Jupiter's innermost moon, Io. The long, narrow features that crisscross Europa also show sulfuric acid that may be from sulfurous material extruded in cracks.

    Galileo, launched in 1989, has been orbiting Jupiter and its moons since December 1995. JPL manages the Galileo mission for NASA's Office of Space Science, Washington DC. JPL is a division of the California Institute of Technology, Pasadena, CA.

  2. Hydrate sulfuric acid after sulfur implantation in water ice

    NASA Astrophysics Data System (ADS)

    Strazzulla, G.; Baratta, G. A.; Leto, G.; Gomis, O.

    2007-12-01

    For many years an ongoing research program performed at our laboratory has had the aim to investigate the implantation of reactive ions in ices relevant to planetology by using IR spectroscopy. We present new results obtained by implanting 200 keV sulfur ions into water ice at 80 K. We have looked at the formation of sulfur-bearing molecules such as sulfuric acid, sulfur dioxide and hydrogen sulfide. We find that hydrated sulfuric acid is formed with high yield ( 0.65±0.1 molecules/ion). An upper limit to the production yield of SO 2 ( Y⩽0.025 molecules/ion) has been estimated; no hydrogen sulfide has been detected. The formation of hydrogen peroxide is confirmed. Ozone is not detected. The results are discussed relevant to the inquiry on the radiolytic sulfur cycle considered responsible for the formation of sulfur-bearing molecules on the surfaces of the Galilean satellites. We demonstrate that sulfur implantation efficiently forms hydrated sulfuric acid whose observed abundance is explained as caused by an exogenic process. It is more difficult to say if the observed sulfur dioxide is quantitatively supported by only sulfur implantation; additional experimental studies are necessary along with direct observations, especially at UV wavelengths such as those that could be performed by instruments on board Hubble Space Telescope or by the forthcoming World Space Observatory (WSO/UV).

  3. Arsenic Trioxide – An Old Drug Rediscovered

    PubMed Central

    Emadi, Ashkan; Gore, Steven D.

    2010-01-01

    Over the last 17 years, clinical trials conducted worldwide have demonstrated the efficacy of arsenic trioxide (As2O3) in the treatment of relapsed acute promyelocytic leukemia (APL). Currently, the role of As2O3 in front-line therapy is under investigation. Recent trials in the US have demonstrated that the addition of As2O3 to standard treatment regimens improves survival outcomes in patients with APL and may allow a reduction in cytotoxic chemotherapy exposure. As2O3 has also shown efficacy in other malignancies, particularly multiple myeloma and myelodysplastic syndromes. Therapeutic doses of As2O3 are well tolerated, with no evidence of long-term toxicity. Adverse events include APL differentiation syndrome, electrocardiographic abnormalities, and mild elevations in liver enzymes. This review highlights trials investigating the role of As2O3 in induction and consolidation for newly diagnosed APL, as well as its role in other hematologic malignancies. The chemistry, mechanisms of action, and clinical side effects of As2O3 are also discussed. PMID:20471733

  4. Investigation of the capacity retention mechanisms in novel composite sulfur copolymer-base cathodes for high-energy density Li-S batteries

    NASA Astrophysics Data System (ADS)

    Oleshko, Vladimir; Kim, Jenny; Masser, Kevin; Hudson, Steven; Soles, Christopher; Griebel, Jared; Chung, Woo Jin; Simmonds, Adam; Pyun, Jeffrey

    2013-03-01

    Utilization of the active cathode material in high-energy density Li-S batteries limited by the insulating nature of sulfur and losses in the form of insoluble polysulfides was improved by the use of 1,3-diisopropenylbenzene (DIB) copolymerized with molten sulfur. This approach termed, inverse vulcanization, transforms elemental sulfur into chemically stable processable copolymer forms with tunable thermomechanical properties. According to dielectric spectroscopy and dc conductivity measurements, composite sulfur-DIB copolymer cathodes exhibit a glassy-state beta relaxation related to short sulfur segments or to the DIB cross-linker. High-resolution AEM and FESEM studies down to the atomic scale reveal multiscale 3D-architectures created within the pristine and cycled composite cathodes with various contents of the electroactive copolymers. The morphology, structures, bonding and local compositional distributions of the constituents (sulfur, copolymers, aggregated conductive carbon nanoparticles) as well as extended pore structures and their transformations under cycling have been examined to provide insights into mechanisms of the enhanced capacity retention in the modified Li-S cells. NIST support under grant MML12-1053-N00

  5. Poly(3,4-ethylene-dioxythiophene)-poly(styrenesulfonate) glued and graphene encapsulated sulfur-carbon film for high-performance free-standing lithium-sulfur batteries

    NASA Astrophysics Data System (ADS)

    Wang, Zhiyu; Cheng, Jianli; Ni, Wei; Gao, Lizhen; Yang, Dan; Razal, Joselito M.; Wang, Bin

    2017-02-01

    A novel free-standing composite film electrode for Li-S battery is investigated. This novel electrode consists of polyvinylpyrrolidone-coated hollow sulfur microspheres (PVPS) that are homogeneously confined within the conductive composite matrix of graphene and poly(3,4-ethylene-dioxythiophene)-poly(styrenesulfonate) (PEDOT-PSS). The characteristic large surface area and wrinkled surface of graphene sheets allow the formation of a conductive layer on the surface of PVPS to suppress the polysulfide dissolution and accommodate the volumetric expansion of sulfur. The addition of PEDOT-PSS also enhances the adhesion between the PVPS and the graphene surface, the overall conductivity of the electrode, and the charge transportation during the charging and discharging processes. The best electrode performances are achieved for a composite film cathode with a sulfur content of about 63.9%, which delivers an initial specific capacity of around 1060 mAh g-1 at 0.1 C. This electrode also displays an excellent capacity retention of 75% after 500 cycles at 1C, corresponding to a capacity decay of only 0.05% per cycle.

  6. Liquid phase deposition synthesis of hexagonal molybdenum trioxide thin films

    SciTech Connect

    Deki, Shigehito; Beleke, Alexis Bienvenu; Kotani, Yuki; Mizuhata, Minoru

    2009-09-15

    Hexagonal molybdenum trioxide thin films with good crystallinity and high purity have been fabricated by the liquid phase deposition (LPD) technique using molybdic acid (H{sub 2}MoO{sub 4}) dissolved in 2.82% hydrofluoric acid (HF) and H{sub 3}BO{sub 3} as precursors. The crystal was found to belong to a hexagonal hydrate system MoO{sub 3}.nH{sub 2}O (napprox0.56). The unit cell lattice parameters are a=10.651 A, c=3.725 A and V=365.997 A{sup 3}. Scanning electron microscope (SEM) images of the as-deposited samples showed well-shaped hexagonal rods nuclei that grew and where the amount increased with increase in reaction time. X-ray photon electron spectroscopy (XPS) spectra showed a Gaussian shape of the doublet of Mo 3d core level, indicating the presence of Mo{sup 6+} oxidation state in the deposited films. The deposited films exhibited an electrochromic behavior by lithium intercalation and deintercalation, which resulted in coloration and bleaching of the film. Upon dehydration at about 450 deg. C, the hexagonal MoO{sub 3}.nH{sub 2}O was transformed into the thermodynamically stable orthorhombic phase. - Abstract: SEM photograph of typical h-MoO{sub 3}.nH{sub 2}O thin film nuclei obtained after 36 h at 40 deg. C by the LPD method. Display Omitted

  7. Photocatalysis and photoelectrochemical properties of tungsten trioxide nanostructured films.

    PubMed

    Lai, Chin Wei

    2014-01-01

    Tungsten trioxide (WO₃) possesses a small band gap energy of 2.4-2.8 eV and is responsive to both ultraviolet and visible light irradiation including strong absorption of the solar spectrum and stable physicochemical properties. Thus, controlled growth of one-dimensional (1D) WO₃ nanotubular structures with desired length, diameter, and wall thickness has gained significant interest. In the present study, 1D WO₃ nanotubes were successfully synthesized via electrochemical anodization of tungsten (W) foil in an electrolyte composed of 1 M of sodium sulphate (Na₂SO₄) and ammonium fluoride (NH₄F). The influence of NH₄F content on the formation mechanism of anodic WO₃ nanotubular structure was investigated in detail. An optimization of fluoride ions played a critical role in controlling the chemical dissolution reaction in the interface of W/WO₃. Based on the results obtained, a minimum of 0.7 wt% of NH₄F content was required for completing transformation from W foil to WO₃ nanotubular structure with an average diameter of 85 nm and length of 250 nm within 15 min of anodization time. In this case, high aspect ratio of WO₃ nanotubular structure is preferred because larger active surface area will be provided for better photocatalytic and photoelectrochemical (PEC) reactions.

  8. A simple synthesis method of sulfur-free Fe-N-C catalyst witih high ORR activity

    SciTech Connect

    Ding, Zhongfen; Johnston, Christina M; Zelenay, Piotr

    2010-01-01

    To try to deconvolute which factors affect the activity and durability of metal-nitrogen-carbon (M-N-C) type non-precious catalysts for oxygen reduction reaction (ORR), M-N-C catalysts based on ion chloride, polyaniline (PANI) and Ketjen Black carbon support were synthesized using different synthetic conditions. The catalysts were characterized electrochemically and tested as cathodes for Hydrogen fuel cells. PANI is usually chemically oxidative polymerized using ammonium persulfate (APS) as oxidant. To eliminate sulfur in the synthesized catalysts, a simple synthesis method using ion chloride as oxidant for aniline polymerization was developed. Two different aniline polymerization conditions led to very different product morphologies. Synthesized at low initial proton concentration, the final product was composed of dense micrometer sized particles. A decomposable salt was found to be able to prohibit PANI cross linking during the drying and annealing process and thus led to porous product. The porous catalyst has much higher ORR activity than the dense product due to more accessible active sites. Synthesized at high proton concentration, the catalyst appeared to be porous. The decomposable salt treatment did not make too much improvement in the porous structure and electrochemical activity. However, fuel cell testing using air as cathode feeder indicates that the salt treatment improves mass transfer in the cathode layer. Catalyst synthesized using this simple method has performance comparable to our state-of-the art catalyst synthesized in a much more complicated procedure. The factor that sulfur sources are completely eliminated in the synthesis suggests that sulfur is not necessary for the ORR catalysis activity.

  9. Highly Efficient Retention of Polysulfides in "Sea Urchin"-Like Carbon Nanotube/Nanopolyhedra Superstructures as Cathode Material for Ultralong-Life Lithium-Sulfur Batteries.

    PubMed

    Chen, Tao; Cheng, Baorui; Zhu, Guoyin; Chen, Renpeng; Hu, Yi; Ma, Lianbo; Lv, Hongling; Wang, Yanrong; Liang, Jia; Tie, Zuoxiu; Jin, Zhong; Liu, Jie

    2017-01-11

    Despite high theoretical energy density, the practical deployment of lithium-sulfur (Li-S) batteries is still not implemented because of the severe capacity decay caused by polysulfide shuttling and the poor rate capability induced by low electrical conductivity of sulfur. Herein, we report a novel sulfur host material based on "sea urchin"-like cobalt nanoparticle embedded and nitrogen-doped carbon nanotube/nanopolyhedra (Co-NCNT/NP) superstructures for Li-S batteries. The hierarchical micromesopores in Co-NCNT/NP can allow efficient impregnation of sulfur and block diffusion of soluble polysulfides by physical confinement, and the incorporation of embedded Co nanoparticles and nitrogen doping (∼4.6 at. %) can synergistically improve the adsorption of polysulfides, as evidenced by beaker cell tests. Moreover, the conductive networks of Co-NCNT/NP interconnected by nitrogen-doped carbon nanotubes (NCNTs) can facilitate electron transport and electrolyte infiltration. Therefore, the specific capacity, rate capability, and cycle stability of Li-S batteries are significantly enhanced. As a result, the Co-NCNT/NP based cathode (loaded with 80 wt % sulfur) delivers a high discharge capacity of 1240 mAh g(-1) after 100 cycles at 0.1 C (based on the weight of sulfur), high rate capacity (755 mAh g(-1) at 2.0 C), and ultralong cycling life (a very low capacity decay of 0.026% per cycle over 1500 cycles at 1.0 C). Remarkably, the composite cathode with high areal sulfur loading of 3.2 mg cm(-2) shows high rate capacities and stable cycling performance over 200 cycles.

  10. Flexible carbon nanofiber/polyvinylidene fluoride composite membranes as interlayers in high-performance Lithiumsbnd Sulfur batteries

    NASA Astrophysics Data System (ADS)

    Wang, Zhenhua; Zhang, Jing; Yang, Yuxiang; Yue, Xinyang; Hao, Xiaoming; Sun, Wang; Rooney, David; Sun, Kening

    2016-10-01

    Traditionally polyvinylidene fluoride membranes have been used in applications such as membrane distillation, wastewater treatment, desalination and separator fabrication. Within this work we demonstrate that a novel carbon nanofiber/polyvinylidene fluoride (CNF/PVDF) composite membrane can be used as an interlayer for Lithiumsbnd Sulfur (Lisbnd S) batteries yielding both high capacity and long cycling life. This PVDF membrane is shown to effectively separate dissolved lithium polysulfide with the high electronic conductivity CNF not only reducing the internal resistance in the sulfur cathode but also helping immobilize the polysulfide through its abundant nanospaces. The resulting Lisbnd S battery assembled with the CNF/PVDF composite membrane effectively solves the polysulfide permeation problem and exhibits excellent electrochemical performance. It is further shown that the CNF/PVDF electrode has an excellent cycling stability and retains a capacity of 768.6 mAh g-1 with a coulombic efficiency above 99% over 200 cycles at 0.5C, which is more than twice that of a cell without CNF/PVDF (374 mAh g-1). In addition, the low-cost raw materials and the simple preparation process of CNF/PVDF composite membrane is also amenable for industrial production.

  11. Sulfur isotopic composition and water chemistry in water from the High Plains aquifer, Oklahoma Panhandle and southwestern Kansas

    USGS Publications Warehouse

    Krothe, Noel C.; Oliver, Joseph W.

    1982-01-01

    The Ogallala Formation comprises the High Plains aquifer in Oklahoma and southwestern Kansas. Regional ground-water flow is from west to east in the Ogallala Formation, and the concentration of dissolved solids in ground water increases in the direction of flow. This increase may be influenced by residence time, but underlying bedrock appears to control ground-water chemistry. The Ogallala Formation is underlain by Mesozoic rocks in the west and Permian rocks in the east. Mean concentration of dissolved solids in ground water from the Mesozoic rocks is 552 milligrams per liter and Permian rocks is 4,720 milligrams per liter. Mean concentration of dissolved solids for water in the Ogallala Formation is 396 milligrams per liter where it overlies Mesozoic rocks and 569 milligrams per liter where it overlies Permian rocks. Del sulfur-34 sulfate values range from a high of +6.9 parts per thousand to a low of -25.1 parts per thousand. Sulfate increases from about 20 milligrams per liter to more than 350 milligrams per liter from west to east. Increasing concentration of dissolved solids, lighter Del sulfur-34 values, and increasing sulfate concentration in the east implies that ground water or hydrogen sulfide from Permian rocks may be moving upward into the Ogallala Formation. (USGS)

  12. Combustion of high-sulfur coal and anthracite wastes in a rotary kiln combustor with an advanced internal air distributor

    SciTech Connect

    Cobb, J.T. Jr. ); Ahn, Y.K. ); Angelo, J.F. )

    1990-01-01

    Fluid bed combustors have received extensive testing with both high-sulfur coal and anthracite wastes. Rotary kilns are effective and popular devices for waste combustion. The Angelo Rotary Furnace{trademark} has been developed to improve the operation of rotary pyrolyzer/combustor systems through enhanced air distribution, which in this process is defined as staged, swirled combustion air injection. Fourteen of these new furnaces have been installed worldwide. Two units in Thailand, designed for rice hull feed with occasional lignite feed, have been recently started up. An older unit in Pennsylvania is being upgraded with a new, more advanced air distribution system for a series of tests this fall in which inexpensive high-sulfur coal and anthracite wastes will be fired with limestone. The purposes of these tests are to determine the burning characteristics of these two fuels in this system, to discover the Ca/S ratios necessary for operation of a rotary kiln combusting these fuels, and to observe the gas-borne emissions from the furnace. An extensive preliminary design study will be performed on a commercial installation for combustion of anthracite wastes. 14 refs., 5 figs., 1 tab.

  13. Identification of the point of diminishing returns in high-multiplicity data collection for sulfur SAD phasing

    PubMed Central

    Storm, Selina L. S.; Dall’Antonia, Fabio; Bourenkov, Gleb; Schneider, Thomas R.

    2017-01-01

    High-quality high-multiplicity X-ray diffraction data were collected on five different crystals of thaumatin using a homogeneous-profile X-ray beam at E = 8 keV to investigate the counteracting effects of increased multiplicity and increased radiation damage on the quality of anomalous diffraction data collected on macromolecular crystals. By comparing sulfur substructures obtained from subsets of the data selected as a function of absorbed X-ray dose with sulfur positions in the respective refined reference structures, the doses at which the highest quality of anomalous differences could be obtained were identified for the five crystals. A statistic σ{ΔF}D, calculated as the width σ of the normalized distribution of a set {ΔF} of anomalous differences collected at a dose D, is suggested as a measure of anomalous data quality as a function of dose. An empirical rule is proposed to identify the dose at which the gains in data quality due to increased multiplicity are outbalanced by the losses due to decreases in signal-to-noise as a consequence of radiation damage. Identifying this point of diminishing returns allows the optimization of the choice of data collection parameters and the selection of data to be used in subsequent crystal structure determination steps. PMID:28009543

  14. Determination of sulfur in human hair using high resolution continuum source graphite furnace molecular absorption spectrometry and its correlation with total protein and albumin

    NASA Astrophysics Data System (ADS)

    Ozbek, Nil; Baysal, Asli

    2017-04-01

    Human hair is a valuable contributor for biological monitoring. It is an information storage point to assess the effects of environmental, nutritional or occupational sources on the body. Human proteins, amino acids or other compounds are among the key components to find the sources of different effects or disorders in the human body. Sulfur is a significant one of these compounds, and it has great affinity to some metals and compounds. This property of the sulfur affects the human health positively or negatively. In this manuscript, sulfur was determined in hair samples of autistic and age-match control group children via molecular absorption of CS using a high-resolution continuum source graphite furnace atomic absorption spectrometer. For this purpose, hair samples were appropriately washed and dried at 75 °C. Then samples were dissolved in microwave digestion using HNO3 for sulfur determination. Extraction was performed with HCl hydrolysation by incubation for 24 h at 110 °C for total protein and albumin determination. The validity of the method for the sulfur determination was tested using hair standard reference materials. The results were in the uncertainty limits of the certified values at 95% confidence level. Finally correlation of sulfur levels of autistic children's hair with their total protein and albumin levels were done.

  15. Reactions of connective tissue to amalgam, intermediate restorative material, mineral trioxide aggregate, and mineral trioxide aggregate mixed with chlorhexidine.

    PubMed

    Sumer, Mahmut; Muglali, Mehtap; Bodrumlu, Emre; Guvenc, Tolga

    2006-11-01

    The aim of this study was to histopathologically examine the biocompatibility of the high-copper amalgam, intermediate restorative material (IRM), mineral trioxide aggregate (MTA), and MTA mixed with chlorhexidine (CHX). This study was conducted to observe the rat subcutaneous connective tissue reaction to the implanted tubes filled with amalgam, IRM, MTA, and MTA mixed with CHX. The animals were sacrificed 15, 30, and 60 days after the implantation procedure. The implant sites were excised and prepared for histological evaluation. Sections of 5 to 6 microm thickness were cut by a microtome and stained with hemotoxylin eosin and examined under a light microscope. The inflammatory reactions were categorized as weak (none or few inflammatory cells < or =25 cells), moderate (>25 cells), and severe (a lot of inflammatory cells not to be counted, giant cells, and granulation tissue). Thickness of fibrous capsules measured five different areas by the digital imaging and the mean values were scored. Amalgam, IRM, and MTA mixed with CHX caused a weak inflammatory response on days 15, 30, and 60. MTA provoked an initial severe inflammatory response that subsided at the 30 and 60 day study period. A clear fibrous capsule was observed beginning from the 15 days in all of the groups. Within the limits of this study, amalgam, IRM, MTA, and MTA mixed with CHX materials were surrounded by fibrous connective tissue indicated that they were well tolerated by the tissues, therefore, MTA/CHX seemed to be biocompatible.

  16. High Permeability Ternary Palladium Alloy Membranes with Improved Sulfur and Halide Tolerances

    SciTech Connect

    K. Coulter

    2010-12-31

    The project team consisting of Southwest Research Institute{reg_sign} (SwRI{reg_sign}), Georgia Institute of Technology (GT), the Colorado School of Mines (CSM), TDA Research, and IdaTech LLC was focused on developing a robust, poison-tolerant, hydrogen selective free standing membrane to produce clean hydrogen. The project completed on schedule and on budget with SwRI, GT, CSM, TDA and IdaTech all operating independently and concurrently. GT has developed a robust platform for performing extensive DFT calculations for H in bulk palladium (Pd), binary alloys, and ternary alloys of Pd. Binary alloys investigated included Pd96M4 where M = Li, Na, Mg, Al, Si, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Y, Zr, Nb, Mo, Tc, Ru, Rh, Ag, Cd, In, Sn, Sb, Te, Hf, Ta, W, Re, Os, Ir, Pt, Au, Tl, Pb, Bi, Ce, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu. They have also performed a series of calculations on Pd{sub 70}Cu{sub 26}Ag{sub 4}, Pd{sub 70}Cu{sub 26}Au{sub 4}, Pd{sub 70}Cu{sub 26}Ni{sub 4}, Pd{sub 70}Cu{sub 26}Pt{sub 4}, and Pd{sub 70}Cu{sub 26}Y{sub 4}. SwRI deposited and released over 160 foils of binary and ternary Pd alloys. There was considerable work on characterizing and improving the durability of the deposited foils using new alloy compositions, post annealing and ion bombardment. The 10 and 25 {micro}m thick films were sent to CSM, TDA and IdaTech for characterization and permeation testing. CSM conducted over 60 pure gas permeation tests with SwRI binary and ternary alloy membranes. To date the PdAu and PdAuPt membranes have exhibited the best performance at temperatures in the range of 423-773 C and their performance correlates well with the predictions from GT. TDA completed testing under the Department of Energy (DOE) WGS conditions on over 16 membranes. Of particular interest are the PdAuPt alloys that exhibited only a 20% drop in flux when sulfur was added to the gas mixture and the flux was completely recovered when the sulfur flow was stopped. IdaTech tested binary

  17. Functionalized graphene-based cathode for highly reversible lithium-sulfur batteries.

    PubMed

    Kim, Jin Won; Ocon, Joey D; Park, Dong-Won; Lee, Jaeyoung

    2014-05-01

    In this article, we highlight the salient issues in the development of lithium-sulfur battery (LSB) cathodes, present different points of view in solving them, and argue, why in the future, functionalized graphene or graphene oxide might be the ultimate solution towards LSB commercialization. As shown by previous studies and also in our recent work, functionalized graphene and graphene oxide enhance the reversibility of the charge-discharge process by trapping polysulfides in the oxygen functional groups on the graphene surface, thus minimizing polysulfide dissolution. This will be helpful for the rational design of new cathode structures based on graphene for LSBs with minimal capacity fading, low extra cost, and without the unnecessary weight increase caused by metal/metal oxide additives.

  18. Thermodynamic modeling of REE behavior in oxidized hydrothermal fluids of high sulfate sulfur concentrations

    NASA Astrophysics Data System (ADS)

    Shironosova, G. P.; Kolonin, G. R.; Borovikov, A. A.; Borisenko, A. S.

    2016-08-01

    Thermodynamic calculations using the HCh software were made for mineral equilibriums including REEs in the fluoride-sulfide-chloride-carbonate-sulfate-system in the presence of Na, Ca, and P with fluids of various acidities-alkalinities [11]. The obtained thermodynamic characteristics of thenardite allowed us to carry out the calculations for this phase under complicated hydrothermal conditions simulating the presence of oxidized fluids at 500-100°C and 2000-125 bar. Among other solid phases, REEs-fluorite, monazite, and REE-F-apatite were formed as CaF2-(Ln,Y)F3, LnPO4, and Ca5(PO4)3F-(Ln,Y)3(PO4)3 ideal solid solutions, respectively, where Ln is La, Ce, Pr, Nd, Sm, Eu, and Gd. Xenotime, anhydrite, elemental sulfur, and calcite were found as well.

  19. Modelling binary homogeneous nucleation of water-sulfuric acid vapours: parameterisation for high temperature emissions.

    PubMed

    Vehkamäki, H; Kulmala, M; Lehtinen, K E J; Noppel, M

    2003-08-01

    Particles formed in the automobile exhaust might form a significant fraction of fine particles in urban air. We have developed a model and produced parametrizations for predicting the particle formation rate at exhaust conditions. We studied the formation in the mixture of water and sulfuric acid vapors and at temperatures between 300 and 400 K. A thermodynamically consistent version of the classical binary homogeneous nucleation model was used. The needed thermodynamical input data (vapor pressures, chemical activities, surface tensions, densities) are carefully investigated and utilized in thermodynamically consistent way. The obtained nucleation rates are parametrized in order to be able to use this nucleation model in aerosol dynamic models, exhaust models, or other process models. The parametrization reduces computational time at least by a factor of 500.

  20. Short-Term Fates of High Sulfur Inputs in Northern California Vineyard Soils

    SciTech Connect

    E Hinckley; S Fendorf; P Matson

    2011-12-31

    The widespread application of elemental sulfur (S{sup 0}) to vineyards may have ecosystem effects at multiple scales. We evaluated the short-term fates of applied S{sup 0} in a Napa Valley vineyard; we determined changes in soil sulfur (S) speciation (measured by X-ray absorption near-edge structure (XANES) spectroscopy), soil pH, extractable sulfate (SO{sub 4}{sup 2-}), and total S to evaluate changes in acidity and soil S within the vineyard over time. Surface soil samples were collected immediately prior to and following two applications of S{sup 0} (6.7 kg S{sup 0} ha{sup -1}), with weekly collections in the 2 weeks between applications and following the last application. XANES spectra indicated that the majority of soil S persists in the +6 oxidation state and that S{sup 0} oxidizes within 7 days following application. Soil pH and extractable SO{sub 4}{sup 2-} measurements taken at 30 min after S{sup 0} application revealed generation of acidity and an increase in extractable SO{sub 4}{sup 2-}, but by 12 days after application, soil pH increased to approximately pre-application levels. These data suggest that the major consequence of reactive S applications in vineyards may be the accumulation of soil SO{sub 4}{sup 2-} and organic S during the growing season, which can be mobilized during storm events during the dormant (wet) season. In spatially-extensive winegrowing regions where these applications are made by hundreds of individual farmers each year, it will be important to understand the long-term implications of this perturbation to the regional S cycle.

  1. Transformations, transport, and potential unintended consequences of high sulfur inputs to Napa Valley vineyards.

    PubMed

    Hinckley, Eve-Lyn S; Matson, Pamela A

    2011-08-23

    Unintended anthropogenic deposition of sulfur (S) to forest ecosystems has a range of negative consequences, identified through decades of research. There has been far less study of purposeful S use in agricultural systems around the world, including the application of elemental sulfur (S(0)) as a quick-reacting fungicide to prevent damage to crops. Here we report results from a three-year study of the transformations and flows of applied S(0) in soils, vegetation, and hydrologic export pathways of Napa Valley, CA vineyards, documenting that all applied S is lost from the vineyard ecosystem on an annual basis. We found that S(0) oxidizes rapidly to sulfate ( ) on the soil surface where it then accumulates over the course of the growing season. Leaf and grape tissues accounted for only 7-13% of applied S whereas dormant season cover crops accounted for 4-10% of applications. Soil S inventories were largely and ester-bonded sulfates; they decreased from 1,623 ± 354 kg ha(-1) during the dry growing season to 981 ± 526 kg ha(-1) (0-0.5 m) during the dormant wet season. Nearly all S applied to the vineyard soils is transported offsite in dissolved oxidized forms during dormant season rainstorms. Thus, the residence time of reactive S is brief in these systems, and largely driven by hydrology. Our results provide new insight into how S use in vineyards constitutes a substantial perturbation of the S cycle in Northern California winegrowing regions and points to the unintended consequences that agricultural S use may have at larger scales.

  2. Transformations, transport, and potential unintended consequences of high sulfur inputs to Napa Valley vineyards

    PubMed Central

    Hinckley, Eve-Lyn S.; Matson, Pamela A.

    2011-01-01

    Unintended anthropogenic deposition of sulfur (S) to forest ecosystems has a range of negative consequences, identified through decades of research. There has been far less study of purposeful S use in agricultural systems around the world, including the application of elemental sulfur (S0) as a quick-reacting fungicide to prevent damage to crops. Here we report results from a three-year study of the transformations and flows of applied S0 in soils, vegetation, and hydrologic export pathways of Napa Valley, CA vineyards, documenting that all applied S is lost from the vineyard ecosystem on an annual basis. We found that S0 oxidizes rapidly to sulfate () on the soil surface where it then accumulates over the course of the growing season. Leaf and grape tissues accounted for only 7–13% of applied S whereas dormant season cover crops accounted for 4–10% of applications. Soil S inventories were largely and ester-bonded sulfates; they decreased from 1,623 ± 354 kg ha-1 during the dry growing season to 981 ± 526 kg ha-1 (0–0.5 m) during the dormant wet season. Nearly all S applied to the vineyard soils is transported offsite in dissolved oxidized forms during dormant season rainstorms. Thus, the residence time of reactive S is brief in these systems, and largely driven by hydrology. Our results provide new insight into how S use in vineyards constitutes a substantial perturbation of the S cycle in Northern California winegrowing regions and points to the unintended consequences that agricultural S use may have at larger scales. PMID:21825150

  3. Ultrafine TiO2 Decorated Carbon Nanofibers as Multifunctional Interlayer for High-Performance Lithium-Sulfur Battery.

    PubMed

    Liang, Gemeng; Wu, Junxiong; Qin, Xianying; Liu, Ming; Li, Qing; He, Yan-Bing; Kim, Jang-Kyo; Li, Baohua; Kang, Feiyu

    2016-09-07

    Although lithium-sulfur (Li-S) batteries deliver high specific energy densities, lots of intrinsic and fatal obstacles still restrict their practical application. Electrospun carbon nanofibers (CNFs) decorated with ultrafine TiO2 nanoparticles (CNF-T) were prepared and used as a multifunctional interlayer to suppress the volume expansion and shuttle effect of Li-S battery. With this strategy, the CNF network with abundant space and superior conductivity can accommodate and recycle the dissolved polysulfides for the bare sulfur cathode. Meanwhile, the ultrafine TiO2 nanoparticles on CNFs work as anchoring points to capture the polysulfides with the strong interaction, making the battery perform with remarkable and stable electrochemical properties. As a result, the Li-S battery with the CNF-T interlayer delivers an initial reversible capacity of 935 mA h g(-1) at 1 C with a capacity retention of 74.2% after 500 cycles. It is believed that this simple, low-cost and scalable method will definitely bring a novel perspective on the practical utilization of Li-S batteries.

  4. Demonstration of SCR technology for the control of NOx emissions from high-sulfur coal-fired utility boilers

    SciTech Connect

    Hinton, W.S.; Maxwell, J.D.; Healy, E.C.; Hardman, R.R.; Baldwin, A.L.

    1997-12-31

    This paper describes the completed Innovative Clean Coal Technology project which demonstrated SCR technology for reduction of flue gas NO{sub x} emissions from a utility boiler burning US high-sulfur coal. The project was sponsored by the US Department of Energy, managed and co-funded by Southern Company Services, Inc. on behalf of the Southern Company, and also co-funded by the Electric Power Research Institute and Ontario Hydro. The project was located at Gulf Power Company`s Plant Crist Unit 5 (a 75 MW tangentially-fired boiler burning US coals that had a sulfur content ranging from 2.5--2.9%), near Pensacola, Florida. The test program was conducted for approximately two years to evaluate catalyst deactivation and other SCR operational effects. The SCR test facility had nine reactors: three 2.5 MW (5,000 scfm), and operated on low-dust flue gas. The reactors operated in parallel with commercially available SCR catalysts obtained from suppliers throughout the world. Long-term performance testing began in July 1993 and was completed in July 1995. A brief test facility description and the results of the project are presented in this paper.

  5. Multidimensional and comprehensive two-dimensional gas chromatography of dichloromethane soluble products from a high sulfur Jordanian oil shale.

    PubMed

    Amer, Mohammad W; Mitrevski, Blagoj; Jackson, W Roy; Chaffee, Alan L; Marriott, Philip J

    2014-03-01

    A high sulfur Jordanian oil shale was converted into liquid hydrocarbons by reaction at 390 °C under N2, and the dichloromethane soluble fraction of the products was isolated then analyzed by using gas chromatography (GC). Comprehensive two-dimensional GC (GC×GC) and multidimensional GC (MDGC) were applied for component separation on a polar - non-polar column set. Flame-ionization detection (FID) was used with GC×GC for general sample profiling, and mass spectrometry (MS) for component identification in MDGC. Multidimensional GC revealed a range of thiophenes (th), benzothiophenes (bth) and small amounts of dibenzothiophenes (dbth) and benzonaphthothiophenes (bnth). In addition, a range of aliphatic alkanes and cycloalkanes, ethers, polar single ring aromatic compounds and small amounts of polycyclic aromatics were also identified. Some of these compound classes were not uniquely observable by conventional 1D GC, and certainly this is true for many of their minor constituent members. The total number of distinct compounds was very large (ca.>1000). GC×GC was shown to be appropriate for general sample profiling, and MDGC-MS proved to be a powerful technique for the separation and identification of sulfur-containing components and other polar compounds.

  6. Ammonium Additives to Dissolve Lithium Sulfide through Hydrogen Binding for High-Energy Lithium-Sulfur Batteries.

    PubMed

    Pan, Huilin; Han, Kee Sung; Vijayakumar, M; Xiao, Jie; Cao, Ruiguo; Chen, Junzheng; Zhang, Jiguang; Mueller, Karl T; Shao, Yuyan; Liu, Jun

    2017-02-08

    In rechargeable Li-S batteries, the uncontrollable passivation of electrodes by highly insulating Li2S limits sulfur utilization, increases polarization, and decreases cycling stability. Dissolving Li2S in organic electrolyte is a facile solution to maintain the active reaction interface between electrolyte and sulfur cathode, and thus address the above issues. Herein, ammonium salts are demonstrated as effective additives to promote the dissolution of Li2S to 1.25 M in DMSO solvent at room temperature. NMR measurements show that the strong hydrogen binding effect of N-H groups plays a critical role in dissolving Li2S by forming complex ligands with S(2-) anions coupled with the solvent's solvating surrounding. Ammonium additives in electrolyte can also significantly improve the oxidation kinetics of Li2S, and therefore enable the direct use of Li2S as cathode material in Li-S battery system in the future. This provides a new approach to manage the solubility of lithium sulfides through cation coordination with sulfide anion.

  7. Ammonium Additives to Dissolve Lithium Sulfide through Hydrogen Binding for High-Energy Lithium–Sulfur Batteries

    SciTech Connect

    Pan, Huilin; Han, Kee Sung; Vijayakumar, M.; Xiao, Jie; Cao, Ruiguo; Chen, Junzheng; Zhang, Jiguang; Mueller, Karl T.; Shao, Yuyan; Liu, Jun

    2016-07-01

    In rechargeable Li-S batteries, the uncontrollable passivation of electrodes by highly insulating Li2S limits sulfur utilization, increases polarization and decreases cycling stability. Dissolving Li2S in organic electrolyte is a facile solution to maintain the active reaction interface between electrolyte and sulfur cathode, and thus address the above issues. Herein, ammonium salts are demonstrated as effective additives to promote the dissolution of Li2S to 1.25 M in DMSO solvent at room temperature. NMR measurements show that the strong hydrogen binding effect of N-H groups plays a critical role in dissolving Li2S by forming complex ligands with S2- anions coupled with the solvent’s solvating surrounding. Ammonium additives in electrolyte can also significantly improve the oxidation kinetics of Li2S, therefore enables the direct use of Li2S as cathode material in Li-S battery system in the future. This provides a new approach to manage the solubility of lithium sulfides through cation coordination with sulfide anion.

  8. Sulfur poisoning of CeO[subscript 2]-Al[subscript 2]O[subscript 3]-supported mono- and bi-metallic Ni and Rh catalysts in steam reforming of liquid hydrocarbons at low and high temperatures

    SciTech Connect

    Xie, Chao; Chen, Yongsheng; Li, Yan; Wang, Xiaoxing; Song, Chunshan

    2010-12-01

    In order to develop a better understanding on sulfur poisoning of reforming catalysts in fuel processing for hydrogen production, steam reforming of liquid hydrocarbons was performed over CeO{sub 2}-Al{sub 2}O{sub 3} supported monometallic Ni and Rh and bimetallic Rh-Ni catalysts at 550 and 800 C. XANES was used to identify the sulfur species in the used catalysts and to study their impacts on the metal surface properties probed by XPS. It was found that both monometallic catalysts rapidly deactivated at 550 C, and showed poor sulfur tolerance. Although ineffective for the Ni catalyst, increasing the temperature to 800 C dramatically improved the sulfur tolerance of the Rh catalyst. XANES revealed that metal sulfide and organic sulfide are the dominant sulfur species on the used Ni catalyst, while sulfonate and sulfate predominate on the used Rh catalyst. The presence of sulfur induced severe carbon deposition on the Ni catalyst at 800 C. The superior sulfur tolerance of the Rh catalyst at 800 C may be associated with its capability in sulfur oxidation. It is likely that the formation of the oxygen-shielded sulfur structure of sulfonate and sulfate can suppress the poisoning impact of sulfur on Rh by inhibiting direct rhodium-sulfur interaction. Moreover, XPS indicated that the metal surface properties of the Rh catalysts after the reaction without and with sulfur at 800 C are similar, suggesting that sulfur poisoning on Rh was mitigated under the high-temperature condition. Although the Rh-Ni catalyst exhibited better sulfur tolerance than the monometallic catalysts at 550 C, its catalytic performance was inferior compared with the Rh catalyst in the sulfur-containing reaction at 800 C probably due to the severe carbon deposition on the bimetallic catalyst.

  9. High-Resolution Infrared Spectroscopy of Carbon-Sulfur Chains: II. C_5S and SC_5S

    NASA Astrophysics Data System (ADS)

    Thorwirth, Sven; Salomon, Thomas; Dudek, John B.

    2016-06-01

    Unbiased high-resolution infrared survey scans of the ablation products from carbon-sulfur targets in the 2100 to 2150 cm-1 regime reveal two bands previously not observed in the gas phase. On the basis of comparison against laboratory matrix-isolation work and new high-level quantum-chemical calculations these bands are attributed to the linear C_5S and SC_5S clusters. While polar C_5S was studied earlier using Fourier-transform microwave techniques, the present work marks the first gas-phase spectroscopic detection of SC_5S. H. Wang, J. Szczepanski, P. Brucat, and M. Vala 2005, Int. J. Quant. Chem. 102, 795 Y. Kasai, K. Obi, Y. Ohshima, Y. Hirahara, Y. Endo, K. Kawaguchi, and A. Murakami 1993, ApJ 410, L45 V. D. Gordon, M. C. McCarthy, A. J. Apponi, and P. Thaddeus 2001, ApJS 134, 311

  10. Electric Power Research Institute, High Sulfur Test Center report to the Steering Committee, March 1994. [Monthly report

    SciTech Connect

    Not Available

    1994-08-01

    Operations and maintenance continued this month at the Electric Power Research Institute`s High Sulfur Test Center. The Suncor Limestone Reagent and Dewatering tests were completed on the Pilot unit this month. As this test block ended, the Pilot unit was modified for the High Velocity Scrubbing tests. This testing began on March 28, 1994 with test PHV-AN. As Phase II of the Mini-Pilot Clear Liquor Scrubbing test block was completed this month, the unit was taken off-line. Testing on the Cold-Side Selective Catalytic Reduction (SCR) unit continued this month as ammonia slip measurements were conducted. Catalyst material from the reactor was inspected and sampled during a scheduled outage this month in preparation for a low temperature test block.

  11. In situ sulfur isotopes (δ(34)S and δ(33)S) analyses in sulfides and elemental sulfur using high sensitivity cones combined with the addition of nitrogen by laser ablation MC-ICP-MS.

    PubMed

    Fu, Jiali; Hu, Zhaochu; Zhang, Wen; Yang, Lu; Liu, Yongsheng; Li, Ming; Zong, Keqing; Gao, Shan; Hu, Shenghong

    2016-03-10

    The sulfur isotope is an important geochemical tracer in diverse fields of geosciences. In this study, the effects of three different cone combinations with the addition of N2 on the performance of in situ S isotope analyses were investigated in detail. The signal intensities of S isotopes were improved by a factor of 2.3 and 3.6 using the X skimmer cone combined with the standard sample cone or the Jet sample cone, respectively, compared with the standard arrangement (H skimmer cone combined with the standard sample cone). This signal enhancement is important for the improvement of the precision and accuracy of in situ S isotope analysis at high spatial resolution. Different cone combinations have a significant effect on the mass bias and mass bias stability for S isotopes. Poor precisions of S isotope ratios were obtained using the Jet and X cones combination at their corresponding optimum makeup gas flow when using Ar plasma only. The addition of 4-8 ml min(-1) nitrogen to the central gas flow in laser ablation MC-ICP-MS was found to significantly enlarge the mass bias stability zone at their corresponding optimum makeup gas flow in these three different cone combinations. The polyatomic interferences of OO, SH, OOH were also significantly reduced, and the interference free plateaus of sulfur isotopes became broader and flatter in the nitrogen mode (N2 = 4 ml min(-1)). However, the signal intensity of S was not increased by the addition of nitrogen in this study. The laser fluence and ablation mode had significant effects on sulfur isotope fractionation during the analysis of sulfides and elemental sulfur by laser ablation MC-ICP-MS. The matrix effect among different sulfides and elemental sulfur was observed, but could be significantly reduced by line scan ablation in preference to single spot ablation under the optimized fluence. It is recommended that the d90 values of the particles in pressed powder pellets for accurate and precise S isotope analysis

  12. Co-combustion characteristics and blending optimization of tobacco stem and high-sulfur bituminous coal based on thermogravimetric and mass spectrometry analyses.

    PubMed

    Zhang, Kaihua; Zhang, Kai; Cao, Yan; Pan, Wei-ping

    2013-03-01

    Despite much research on co-combustion of tobacco stem and high-sulfur coal, their blending optimization has not been effectively found. This study investigated the combustion profiles of tobacco stem, high-sulfur bituminous coal and their blends by thermogravimetric analysis. Ignition and burnout performances, heat release performances, and gaseous pollutant emissions were also studied by thermogravimetric and mass spectrometry analyses. The results indicated that combustion of tobacco stem was more complicated than that of high-sulfur bituminous coal, mainly shown as fixed carbon in it was divided into two portions with one early burning and the other delay burning. Ignition and burnout performances, heat release performances, and gaseous pollutant emissions of the blends present variable trends with the increase of tobacco stem content. Taking into account the above three factors, a blending ratio of 0–20% tobacco stem content is conservatively proposed as optimum amount for blending.

  13. Conductive Carbon Network inside a Sulfur-Impregnated Carbon Sponge: A Bioinspired High-Performance Cathode for Li-S Battery.

    PubMed

    Du, Xue-Li; You, Ya; Yan, Yang; Zhang, Dawei; Cong, Huai-Ping; Qin, Haili; Zhang, Chaofeng; Cao, Fei-Fei; Jiang, Ke-Cheng; Wang, Yan; Xin, Sen; He, Jian-Bo

    2016-08-31

    A highly conductive sulfur cathode is crucial for improving the kinetic performance of a Li-S battery. The encapsulation of sulfur in porous nanocarbons is expected to benefit the Li(+) migration, yet the e(-) conduction is still to be improved due to a low graphitization degree of a conventional carbon substrate, especially that pyrolyzed from carbohydrates or polymers. Aiming at facilitating the e(-) conduction in the cathode, here we propose to use ketjen black, a highly graphitized nanocarbon building block to form a conductive network for electrons in a biomass-derived, hierarchically porous carbon sponge by a easily scaled-up approach at a low cost. The specifically designed carbon host ensures a high loading and good retention of active sulfur, while also provides a faster electron transmission to benefit the lithiation/delithiation kinetics of sulfur. The sulfur cathode prepared from the carbon network shows excellent cycling and rate performance in a Li-S battery, rendering its practicality for emerging energy storage opportunities such as grids or automobiles.

  14. Synthesis of highly ordered mesoporous crystalline WS(2) and MoS(2) via a high-temperature reductive sulfuration route.

    PubMed

    Shi, Yifeng; Wan, Ying; Liu, Ruili; Tu, Bo; Zhao, Dongyuan

    2007-08-01

    A high-temperature reductive sulfuration method is demonstrated to synthesize highly ordered mesoporous metal sulfide crystallites by using mesoporous silica as hard templates. H2S gas is utilized as a sulfuration agent to in situ convert phosphotungstic acid H3PW12O40.6H2O to hexagonal WS2 crystallites in the silica nanochannels at 600 degrees C. Upon etching silica, mesoporous, layered WS2 nanocrystal arrays are produced with a yield as high as 96 wt %. XRD, nitrogen sorption, SEM, and TEM results reveal that the WS2 products replicated from the mesoporous silica SBA-15 hard template possess highly ordered hexagonal mesostructure (space group, p6mm) and rodlike morphology, analogous to the mother template. The S-W-S trilayers of the WS2 nanocrystals are partially oriented, parallel to the mesochannels of the SBA-15 template. This orientation is related with the reduction of the high-energy layer edges in layered metal dichalcogenides and the confinement in anisotropic nanochannels. The mesostructure can be 3-D cubic bicontinuous if KIT-6 (Iad) is used as a hard template. Mesoporous WS2 replicas have large surface areas (105-120 m2/g), pore volumes ( approximately 0.20 cm3/g), and narrow pore size distributions ( approximately 4.8 nm). By one-step nanocasting with the H3PMo12O40.6H2O (PMA) precursor into the mesochannels of SBA-15 or KIT-6 hard template, highly ordered mesoporous MoS2 layered crystallites with the 2-D hexagonal (p6mm) and 3-D bicontinuous cubic (Iad) structures can also be prepared via this high-temperature reductive sulfuration route. When the loading amount of PMA precursor is low, multiwalled MoS2 nanotubes with 5-7 nm in diameter can be obtained. The high-temperature reductive sulfuration method is a general strategy and can be extended to synthesize mesoporous CdS crystals and other metal sulfides.

  15. High sulfur isotope fractionation associated with anaerobic oxidation of methane in a low sulfate, iron rich environment

    NASA Astrophysics Data System (ADS)

    Weber, Hannah; Thamdrup, Bo; Habicht, Kirsten

    2016-06-01

    Sulfur isotope signatures provide key information for the study of microbial activity in modern systems and the evolution of the Earth surface redox system. Microbial sulfate reducers shift sulfur isotope distributions by discriminating against heavier isotopes. This discrimination is strain-specific and often suppressed at sulfate concentrations in the lower micromolar range that are typical to freshwater systems and inferred for ancient oceans. Anaerobic oxidation of methane (AOM) is a sulfate-reducing microbial process with a strong impact on global sulfur cycling in modern habitats and potentially in the geological past, but its impact on sulfur isotope signatures is poorly understood, especially in low sulfate environments. We investigated sulfur cycling and 34S fractionation in a low-sulfate freshwater sediment with biogeochemical conditions analogous to Early Earth environments. The zone of highest AOM activity was associated in situ with a zone of strong 34S depletions in the pool of reduced sulfur species, indicating a coupling of sulfate reduction and AOM at sulfate concentrations < 50 µmol L-1. In slurry incubations of AOM-active sediment, the addition of methane stimulated sulfate reduction and induced a bulk sulfur isotope effect of ~29 ‰. Our results imply that sulfur isotope signatures may be strongly impacted by AOM even at sulfate concentrations two orders of magnitude lower than at present oceanic levels. Therefore, we suggest that sulfur isotope fractionation during AOM must be considered when interpreting 34S signatures in modern and ancient environment.

  16. Detangling the Web of Sulfur Metabolisms in Santa Barbara Basin with High-Resolution δ34S and Genomic Profiles

    NASA Astrophysics Data System (ADS)

    Raven, M. R.; Adkins, J. F.; Sessions, A. L.; Dawson, K.; Connon, S. A.; Orphan, V. J.

    2014-12-01

    Sulfur metabolisms are major drivers of organic matter remineralization and microbial growth in marine sediments. Sulfur-isotope systematics are particularly powerful for interrogating metabolic processes in these systems due to the large sulfur-isotope fractionations associated with bacterial sulfate reduction (BSR) and some other metabolic reactions. Recent analytical advancements have made it possible to measure δ34S values of very small samples (>50 nmol), including aqueous sulfate and sulfide as well as pyrite, elemental sulfur, and multiple fractions of sedimentary organic matter. We have generated comprehensive 2.5 cm-resolution depth profiles of these sulfur pools over a 2-m core from Santa Barbara Basin, a sub-oxic environment off the California coast. We find that the porewater sulfide δ34S values appear to be strongly influenced by anaerobic sulfide oxidation and sulfur disproportionation in addition to BSR. These sulfur-isotope signals can be tracked over the course of several thousand years of sediment diagenesis, moving from the oxic-anoxic transition at the sediment-water interface to the sulfate-methane transition zone in deeper sediments. Shifts in δ34S relationships among sulfur pools correlate with changes in microbial community composition as shown in TAG genomic data, which supports the existence of the metabolisms indicated by δ34S profiles. Our results suggest that the existence and activity of multiple microbial communities and coexisting sulfur metabolisms have the potential to be recorded in sedimentary δ34S records.

  17. Catalyst for the reduction of sulfur dioxide to elemental sulfur

    DOEpatents

    Jin, Y.; Yu, Q.; Chang, S.G.

    1996-02-27

    The inventive catalysts allow for the reduction of sulfur dioxide to elemental sulfur in smokestack scrubber environments. The catalysts have a very high sulfur yield of over 90% and space velocity of 10,000 h{sup {minus}1}. They also have the capacity to convert waste gases generated during the initial conversion into elemental sulfur. The catalysts have inexpensive components, and are inexpensive to produce. The net impact of the invention is to make this technology practically available to industrial applications. 21 figs.

  18. The Sulfur Oxygenase Reductase from the Mesophilic Bacterium Halothiobacillus neapolitanus Is a Highly Active Thermozyme

    PubMed Central

    Veith, Andreas; Botelho, Hugo M.; Kindinger, Florian; Gomes, Cláudio M.

    2012-01-01

    A biochemical, biophysical, and phylogenetic study of the sulfur oxygenase reductase (SOR) from the mesophilic gammaproteobacterium Halothiobacillus neapolitanus (HnSOR) was performed in order to determine the structural and biochemical properties of the enzyme. SOR proteins from 14 predominantly chemolithoautotrophic bacterial and archaeal species are currently available in public databases. Sequence alignment and phylogenetic analysis showed that they form a coherent protein family. The HnSOR purified from Escherichia coli after heterologous gene expression had a temperature range of activity of 10 to 99°C with an optimum at 80°C (42 U/mg protein). Sulfite, thiosulfate, and hydrogen sulfide were formed at various stoichiometries in a range between pH 5.4 and 11 (optimum pH 8.4). Circular dichroism (CD) spectroscopy and dynamic light scattering showed that the HnSOR adopts secondary and quaternary structures similar to those of the 24-subunit enzyme from the hyperthermophile Acidianus ambivalens (AaSOR). The melting point of the HnSOR was ≈20°C lower than that of the AaSOR, when analyzed with CD-monitored thermal unfolding. Homology modeling showed that the secondary structure elements of single subunits are conserved. Subtle changes in the pores of the outer shell and increased flexibility might contribute to activity at low temperature. We concluded that the thermostability was the result of a rigid protein core together with the stabilizing effect of the 24-subunit hollow sphere. PMID:22139503

  19. Controlled Growth of Platinum Nanowire Arrays on Sulfur Doped Graphene as High Performance Electrocatalyst

    PubMed Central

    Wang, Rongyue; Higgins, Drew C.; Hoque, Md Ariful; Lee, DongUn; Hassan, Fathy; Chen, Zhongwei

    2013-01-01

    Graphene supported Pt nanostructures have great potential to be used as catalysts in electrochemical energy conversion and storage technologies; however the simultaneous control of Pt morphology and dispersion, along with ideally tailoring the physical properties of the catalyst support properties has proven very challenging. Using sulfur doped graphene (SG) as a support material, the heterogeneous dopant atoms could serve as nucleation sites allowing for the preparation of SG supported Pt nanowire arrays with ultra-thin diameters (2–5 nm) and dense surface coverage. Detailed investigation of the preparation technique reveals that the structure of the resulting composite could be readily controlled by fine tuning the Pt nanowire nucleation and growth reaction kinetics and the Pt-support interactions, whereby a mechanistic platinum nanowire array growth model is proposed. Electrochemical characterization demonstrates that the composite materials have 2–3 times higher catalytic activities toward the oxygen reduction and methanol oxidation reaction compared with commercial Pt/C catalyst. PMID:23942256

  20. Determination of total sulfur in fertilizers by high temperature combustion: single-laboratory validation.

    PubMed

    Bernius, Jean; Kraus, Sabine; Hughes, Sandra; Margraf, Dominik; Bartos, James; Newlon, Natalie; Sieper, Hans-Peter

    2014-01-01

    Asingle-laboratory validation study was conducted for the determination of total sulfur (S) in a variety of common, inorganic fertilizers by combustion. The procedure involves conversion of S species into SO2 through combustion at 1150 degrees C, absorption then desorption from a purge and trap column, followed by measurement by a thermal conductivity detector. Eleven different validation materials were selected for study, which included four commercial fertilizer products, five fertilizers from the Magruder Check Sample Program, one reagent grade product, and one certified organic reference material. S content ranged between 1.47 and 91% as sulfate, thiosulfate, and elemental and organically bound S. Determinations of check samples were performed on 3 different days with four replicates/day. Determinations for non-Magruder samples were performed on 2 different days. Recoveries ranged from 94.3 to 125.9%. ABS SL absolute SD among runs ranged from 0.038 to 0.487%. Based on the accuracy and precision demonstrated here, it is recommended that this method be collaboratively studied for the determination of total S in fertilizers.

  1. COMBINED RETENTION OF MOLYBDENUM AND SULFUR IN SIMULATED HIGH LEVEL WASTE GLASS

    SciTech Connect

    Fox, K.

    2009-10-16

    This study was undertaken to investigate the effect of elevated sulfate and molybdenum concentrations in nuclear waste glasses. A matrix of 24 glasses was developed and the glasses were tested for acceptability based on visual observations, canister centerline-cooled heat treatments, and chemical composition analysis. Results from the chemical analysis of the rinse water from each sample were used to confirm the presence of SO{sup 2-}{sub 4} and MoO{sub 3} on the surface of glasses as well as other components which might form water soluble compounds with the excess sulfur and molybdenum. A simple, linear model was developed to show acceptable concentrations of SO{sub 4}{sup 2-} and MoO{sub 3} in an example waste glass composition. This model was constructed for scoping studies only and is not ready for implementation in support of actual waste vitrification. Several other factors must be considered in determining the limits of sulfate and molybdenum concentrations in the waste vitrification process, including but not limited to, impacts on refractory and melter component corrosion, effects on the melter off-gas system, and impacts on the chemical durability and crystallization of the glass product.

  2. Improved Outcomes With Retinoic Acid and Arsenic Trioxide Compared With Retinoic Acid and Chemotherapy in Non-High-Risk Acute Promyelocytic Leukemia: Final Results of the Randomized Italian-German APL0406 Trial.

    PubMed

    Platzbecker, Uwe; Avvisati, Giuseppe; Cicconi, Laura; Thiede, Christian; Paoloni, Francesca; Vignetti, Marco; Ferrara, Felicetto; Divona, Mariadomenica; Albano, Francesco; Efficace, Fabio; Fazi, Paola; Sborgia, Marco; Di Bona, Eros; Breccia, Massimo; Borlenghi, Erika; Cairoli, Roberto; Rambaldi, Alessandro; Melillo, Lorella; La Nasa, Giorgio; Fiedler, Walter; Brossart, Peter; Hertenstein, Bernd; Salih, Helmut R; Wattad, Mohammed; Lübbert, Michael; Brandts, Christian H; Hänel, Mathias; Röllig, Christoph; Schmitz, Norbert; Link, Hartmut; Frairia, Chiara; Pogliani, Enrico Maria; Fozza, Claudio; D'Arco, Alfonso Maria; Di Renzo, Nicola; Cortelezzi, Agostino; Fabbiano, Francesco; Döhner, Konstanze; Ganser, Arnold; Döhner, Hartmut; Amadori, Sergio; Mandelli, Franco; Ehninger, Gerhard; Schlenk, Richard F; Lo-Coco, Francesco

    2017-02-20

    Purpose The initial results of the APL0406 trial showed that the combination of all- trans-retinoic acid (ATRA) and arsenic trioxide (ATO) is at least not inferior to standard ATRA and chemotherapy (CHT) in first-line therapy of low- or intermediate-risk acute promyelocytic leukemia (APL). We herein report the final analysis on the complete series of patients enrolled onto this trial. Patients and Methods The APL0406 study was a prospective, randomized, multicenter, open-label, phase III noninferiority trial. Eligible patients were adults between 18 and 71 years of age with newly diagnosed, low- or intermediate-risk APL (WBC at diagnosis ≤ 10 × 10(9)/L). Overall, 276 patients were randomly assigned to receive ATRA-ATO or ATRA-CHT between October 2007 and January 2013. Results Of 263 patients evaluable for response to induction, 127 (100%) of 127 patients and 132 (97%) of 136 patients achieved complete remission (CR) in the ATRA-ATO and ATRA-CHT arms, respectively ( P = .12). After a median follow-up of 40.6 months, the event-free survival, cumulative incidence of relapse, and overall survival at 50 months for patients in the ATRA-ATO versus ATRA-CHT arms were 97.3% v 80%, 1.9% v 13.9%, and 99.2% v 92.6%, respectively ( P < .001, P = .0013, and P = .0073, respectively). Postinduction events included two relapses and one death in CR in the ATRA-ATO arm and two instances of molecular resistance after third consolidation, 15 relapses, and five deaths in CR in the ATRA-CHT arm. Two patients in the ATRA-CHT arm developed a therapy-related myeloid neoplasm. Conclusion These results show that the advantages of ATRA-ATO over ATRA-CHT increase over time and that there is significantly greater and more sustained antileukemic efficacy of ATO-ATRA compared with ATRA-CHT in low- and intermediate-risk APL.

  3. The NRF2-mediated oxidative stress response pathway is associated with tumor cell resistance to arsenic trioxide across the NCI-60 panel

    PubMed Central

    2010-01-01

    Background Drinking water contaminated with inorganic arsenic is associated with increased risk for different types of cancer. Paradoxically, arsenic trioxide can also be used to induce remission in patients with acute promyelocytic leukemia (APL) with a success rate of approximately 80%. A comprehensive study examining the mechanisms and potential signaling pathways contributing to the anti-tumor properties of arsenic trioxide has not been carried out. Methods Here we applied a systems biology approach to identify gene biomarkers that underlie tumor cell responses to arsenic-induced cytotoxicity. The baseline gene expression levels of 14,500 well characterized human genes were associated with the GI50 data of the NCI-60 tumor cell line panel from the developmental therapeutics program (DTP) database. Selected biomarkers were tested in vitro for the ability to influence tumor susceptibility to arsenic trioxide. Results A significant association was found between the baseline expression levels of 209 human genes and the sensitivity of the tumor cell line panel upon exposure to arsenic trioxide. These genes were overlayed onto protein-protein network maps to identify transcriptional networks that modulate tumor cell responses to arsenic trioxide. The analysis revealed a significant enrichment for the oxidative stress response pathway mediated by nuclear factor erythroid 2-related factor 2 (NRF2) with high expression in arsenic resistant tumor cell lines. The role of the NRF2 pathway in protecting cells against arsenic-induced cell killing was validated in tumor cells using shRNA-mediated knock-down. Conclusions In this study, we show that the expression level of genes in the NRF2 pathway serve as potential gene biomarkers of tumor cell responses to arsenic trioxide. Importantly, we demonstrate that tumor cells that are deficient for NRF2 display increased sensitivity to arsenic trioxide. The results of our study will be useful in understanding the mechanism of

  4. A maize gene encoding an NADPH binding enzyme highly homologous to isoflavone reductases is activated in response to sulfur starvation.

    PubMed

    Petrucco, S; Bolchi, A; Foroni, C; Percudani, R; Rossi, G L; Ottonello, S

    1996-01-01

    we isolated a novel gene that is selectively induced both in roots and shoots in response to sulfur starvation. This gene encodes a cytosolic, monomeric protein of 33 kD that selectively binds NADPH. The predicted polypeptide is highly homologous ( > 70%) to leguminous isoflavone reductases (IFRs), but the maize protein (IRL for isoflavone reductase-like) belongs to a novel family of proteins present in a variety of plants. Anti-IRL antibodies specifically recognize IFR polypeptides, yet the maize protein is unable to use various isoflavonoids as substrates. IRL expression is correlated closely to glutathione availability: it is persistently induced in seedlings whose glutathione content is about fourfold lower than controls, and it is down-regulated rapidly when control levels of glutathione are restored. This glutathione-dependent regulation indicates that maize IRL may play a crucial role in the establishment of a thiol-independent response to oxidative stress under glutathione shortage conditions.

  5. A maize gene encoding an NADPH binding enzyme highly homologous to isoflavone reductases is activated in response to sulfur starvation.

    PubMed Central

    Petrucco, S; Bolchi, A; Foroni, C; Percudani, R; Rossi, G L; Ottonello, S

    1996-01-01

    we isolated a novel gene that is selectively induced both in roots and shoots in response to sulfur starvation. This gene encodes a cytosolic, monomeric protein of 33 kD that selectively binds NADPH. The predicted polypeptide is highly homologous ( > 70%) to leguminous isoflavone reductases (IFRs), but the maize protein (IRL for isoflavone reductase-like) belongs to a novel family of proteins present in a variety of plants. Anti-IRL antibodies specifically recognize IFR polypeptides, yet the maize protein is unable to use various isoflavonoids as substrates. IRL expression is correlated closely to glutathione availability: it is persistently induced in seedlings whose glutathione content is about fourfold lower than controls, and it is down-regulated rapidly when control levels of glutathione are restored. This glutathione-dependent regulation indicates that maize IRL may play a crucial role in the establishment of a thiol-independent response to oxidative stress under glutathione shortage conditions. PMID:8597660

  6. Sulfurizing-Induced Hollowing of Co9S8 Microplates with Nanosheet Units for Highly Efficient Water Oxidation.

    PubMed

    Liu, Huan; Ma, Fei-Xiang; Xu, Cheng-Yan; Yang, Li; Du, Yue; Wang, Pan-Pan; Yang, Shuang; Zhen, Liang

    2017-03-14

    Transition metal-based compounds are promising alternative non-precious electrocatalysts for hydrogen and oxygen evolution to noble metals-based materials. Nanosheets-constructed hollow structures can efficiently promote the electrocatalystic activity, mainly because of their largely exposed active sites. Herein, hierarchical Co9S8 hollow microplates with nanosheet building units are fabricated via sulfurization and subsequent calcination of pre-formed Co-glycolate microplates. Benefited from the advantages of hollow structure, nanosheet units and high Co3+ content, Co9S8 hollow microplates exhibit remarkable catalytic performance for oxygen evolution reaction (OER) with low overpotential of 278 mV to reach current density of 10 mA cm-2, low Tafel slope of 53 mV dec-1 and satisfied stability. This construction method of Co9S8 hierarchical hollow microplates composing by nanosheets structure is an effective tactics for promoting OER performance of water splitting electrocatalysts.

  7. Electronic and ionic co-conductive coating on the separator towards high-performance lithium-sulfur batteries

    NASA Astrophysics Data System (ADS)

    Wang, Qingsong; Wen, Zhaoyin; Yang, Jianhua; Jin, Jun; Huang, Xiao; Wu, Xiangwei; Han, Jinduo

    2016-02-01

    A thin coating layer composed of the mixture of the electronic conductive carbon and lithium ionic conductive inorganic solid electrolyte was introduced on one side of the routine Celgard separator. This functional coated separator is designed to localize the polysulfides on the cathode side and act as an upper current collector for further utilization of sulfur while alleviating the ion conductivity decrease induced by the dissolved polysulfides in the discharge and charge process. Moreover, catalytic conversion of polysulfides by the solid state highly ionic conductor is observed. This brings significant improvement in battery specific capacity and cycling stability, with an initial discharge capacity of 1247 mA h g-1 and a reversible capacity of 830 mA h g-1 after 150 extended cycles at 0.5 C rate. Rest-testing proves a low self-discharge and excellent capacity retention of the modified cells.

  8. [Measurement of lead in high-salt food with sulfuric-nitric acid to treat food ash].

    PubMed

    Shi, Y; Zhang, Y; Wang, Y

    2001-03-01

    Lead in high-salt food was measured by treating the ash with sulfuric-nitric acid, and diluting lead standard with sodium sulfate to eliminate the disturbance of chloride in detecting lead with atomic absorption spectrophotometry. The minimum detection limit was 0.10 mg/kg. The relative standard deviation is 1.72%, 5.00% and 7.14% while the amount of lead was 8.70, 2.40 and 1.40 micrograms respectively. The recovery varied between 90.0%-109.0%. There was no significant difference (P > 0.05) of the lead content between the mentioned method and extraction flame photometry. The amount of lead is higher obviously than that of other two methods by eliminating the disturbance of chloride. The method was simple, precise and accurate, and suitable for hygienic examination.

  9. Effects of high-sulfur water and clinoptilolite on health and growth performance of steers fed forage-based diets.

    PubMed

    Cammack, K M; Wright, C L; Austin, K J; Johnson, P S; Cockrum, R R; Kessler, K L; Olson, K C

    2010-05-01

    Sulfur-induced polioencephalomalacia (sPEM), a neurological disorder affecting ruminants, is associated with consumption of diets with increased S (high-S). High-S water is commonly found in many western states and is a major source of dietary S for grazing cattle. Consumption of high-S water has been associated with sPEM and decreased performance. Identification of a feed supplement that would counteract the negative effects of high-S water would decrease the incidence of sPEM and prevent performance reductions in regions with problematic water sources. The objectives of this study were to 1) determine the effects of administering high-S drinking water to forage-fed feedlot steers on health and performance, and 2) determine the effectiveness of clinoptilolite, a clay mineral with increased cation-exchange capacity, in negating the effects of high-S drinking water. Yearling steers (n = 96; 318.2 +/- 2.1 kg of BW) were randomly assigned to 1 of 4 treatments for a 77-d trial period: control with low-S water (566 mg of SO(4)/L), high-S water (3,651 mg of SO(4)/L), or high-S water plus clinoptilolite supplemented at 2.5 or 5.0% of the diet DM. Feed and water consumption were measured daily, and all steers were weighed on d -2, -1, 29, 53, 76, and 77. Plasma samples were collected on d 0, 58, and 77, and liver samples on d 0 and 77. There was a greater (P high-S steers than control steers, but no differences among high-S treatment groups. In total, 12 cases of sPEM were confirmed by the presence of cortical lesions in steers consuming high-S water. Daily DMI (P = 0.002) and daily water intake (P = 0.001) were less in high-S water steers than control steers. No differences (P >or= 0.546) in ADG or G:F were observed. Plasma Cu decreased (P = 0.029) to a greater magnitude in high-S water steers than the control steers over the 77-d trial period. Mineral analyses of hepatic tissue from randomly selected healthy steers from each treatment

  10. Flexible neutron shielding composite material of EPDM rubber with boron trioxide: Mechanical, thermal investigations and neutron shielding tests

    NASA Astrophysics Data System (ADS)

    Özdemir, T.; Güngör, A.; Reyhancan, İ. A.

    2017-02-01

    In this study, EPDM and boron trioxide composite was produced and mechanical, thermal and neutron shielding tests were performed. EPDM rubber (Ethylene Propylene Diene Monomer) having a considerably high hydrogen content is an effective neutron shielding material. On the other hand, the materials containing boron components have effective thermal neutron absorption crossection. The composite of EPDM and boron trioxide would be an effective solution for both respects of flexibility and effectiveness for developing a neutron shielding material. Flexible nature of EPDM would be a great asset for the shielding purpose in case of intervention action to a radiation accident. The theoretical calculations and experimental neutron absorption tests have shown that the results were in parallel and an effective neutron shielding has been achieved with the use of the developed composite material.

  11. Potential role of stabilized Criegee radicals in sulfuric acid production in a high biogenic VOC environment.

    PubMed

    Kim, Saewung; Guenther, Alex; Lefer, Barry; Flynn, James; Griffin, Robert; Rutter, Andrew P; Gong, Longwen; Cevik, Basak Karakurt

    2015-03-17

    We present field observations made in June 2011 downwind of Dallas-Fort Worth, TX, and evaluate the role of stabilized Criegee radicals (sCIs) in gaseous sulfuric acid (H2SO4) production. Zero-dimensional model calculations show that sCI from biogenic volatile organic compounds composed the majority of the sCIs. The main uncertainty associated with an evaluation of H2SO4 production from the sCI reaction channel is the lack of experimentally determined reaction rates for sCIs formed from isoprene ozonolysis with SO2 along with systematic discrepancies in experimentally derived reaction rates between other sCIs and SO2 and water vapor. In general, the maximum of H2SO4 production from the sCI channel is found in the late afternoon as ozone increases toward the late afternoon. The sCI channel, however, contributes minor H2SO4 production compared with the conventional OH channel in the mid-day. Finally, the production and the loss rates of H2SO4 are compared. The application of the recommended mass accommodation coefficient causes significant overestimation of H2SO4 loss rates compared with H2SO4 production rates. However, the application of a lower experimental value for the mass accommodation coefficient provides good agreement between the loss and production rates of H2SO4. The results suggest that the recommended coefficient for the H2O surface may not be suitable for this relatively dry environment.

  12. Plume Tracker: Interactive mapping of volcanic sulfur dioxide emissions with high-performance radiative transfer modeling

    NASA Astrophysics Data System (ADS)

    Realmuto, Vincent J.; Berk, Alexander

    2016-11-01

    We describe the development of Plume Tracker, an interactive toolkit for the analysis of multispectral thermal infrared observations of volcanic plumes and clouds. Plume Tracker is the successor to MAP_SO2, and together these flexible and comprehensive tools have enabled investigators to map sulfur dioxide (SO2) emissions from a number of volcanoes with TIR data from a variety of airborne and satellite instruments. Our objective for the development of Plume Tracker was to improve the computational performance of the retrieval procedures while retaining the accuracy of the retrievals. We have achieved a 300 × improvement in the benchmark performance of the retrieval procedures through the introduction of innovative data binning and signal reconstruction strategies, and improved the accuracy of the retrievals with a new method for evaluating the misfit between model and observed radiance spectra. We evaluated the accuracy of Plume Tracker retrievals with case studies based on MODIS and AIRS data acquired over Sarychev Peak Volcano, and ASTER data acquired over Kilauea and Turrialba Volcanoes. In the Sarychev Peak study, the AIRS-based estimate of total SO2 mass was 40% lower than the MODIS-based estimate. This result was consistent with a 45% reduction in the AIRS-based estimate of plume area relative to the corresponding MODIS-based estimate. In addition, we found that our AIRS-based estimate agreed with an independent estimate, based on a competing retrieval technique, within a margin of ± 20%. In the Kilauea study, the ASTER-based concentration estimates from 21 May 2012 were within ± 50% of concurrent ground-level concentration measurements. In the Turrialba study, the ASTER-based concentration estimates on 21 January 2012 were in exact agreement with SO2 concentrations measured at plume altitude on 1 February 2012.

  13. Designing and Validating Ternary Pd Alloys for Optimum Sulfur/Carbon Resistance in Hydrogen Separation and Carbon Capture Membrane Systems Using High-Throughput Combinatorial Methods

    SciTech Connect

    Lewis, Amanda; Zhao, Hongbin; Hopkins, Scott

    2014-12-01

    This report summarizes the work completed under the U.S. Department of Energy Project Award No.: DE-FE0001181 titled “Designing and Validating Ternary Pd Alloys for Optimum Sulfur/Carbon Resistance in Hydrogen Separation and Carbon Capture Membrane Systems Using High-Throughput Combinatorial Methods.” The project started in October 1, 2009 and was finished September 30, 2014. Pall Corporation worked with Cornell University to sputter and test palladium-based ternary alloys onto silicon wafers to examine many alloys at once. With the specialized equipment at Georgia Institute of Technology that analyzed the wafers for adsorbed carbon and sulfur species six compositions were identified to have resistance to carbon and sulfur species. These compositions were deposited on Pall AccuSep® supports by Colorado School of Mines and then tested in simulated synthetic coal gas at the Pall Corporation. Two of the six alloys were chosen for further investigations based on their performance. Alloy reproducibility and long-term testing of PdAuAg and PdZrAu provided insight to the ability to manufacture these compositions for testing. PdAuAg is the most promising alloy found in this work based on the fabrication reproducibility and resistance to carbon and sulfur. Although PdZrAu had great initial resistance to carbon and sulfur species, the alloy composition has a very narrow range that hindered testing reproducibility.

  14. A Role for Iron-Sulfur Clusters in the Regulation of Transcription Factor Yap5-dependent High Iron Transcriptional Responses in Yeast*

    PubMed Central

    Li, Liangtao; Miao, Ren; Bertram, Sophie; Jia, Xuan; Ward, Diane M.; Kaplan, Jerry

    2012-01-01

    Yeast respond to increased cytosolic iron by activating the transcription factor Yap5 increasing transcription of CCC1, which encodes a vacuolar iron importer. Using a genetic screen to identify genes involved in Yap5 iron sensing, we discovered that a mutation in SSQ1, which encodes a mitochondrial chaperone involved in iron-sulfur cluster synthesis, prevented expression of Yap5 target genes. We demonstrated that mutation or reduced expression of other genes involved in mitochondrial iron-sulfur cluster synthesis (YFH1, ISU1) prevented induction of the Yap5 response. We took advantage of the iron-dependent catalytic activity of Pseudaminobacter salicylatoxidans gentisate 1,2-dioxygenase expressed in yeast to measure changes in cytosolic iron. We determined that reductions in iron-sulfur cluster synthesis did not affect the activity of cytosolic gentisate 1,2-dioxygenase. We show that loss of activity of the cytosolic iron-sulfur cluster assembly complex proteins or deletion of cytosolic glutaredoxins did not reduce expression of Yap5 target genes. These results suggest that the high iron transcriptional response, as well as the low iron transcriptional response, senses iron-sulfur clusters. PMID:22915593

  15. Controlling the Active Sites of Sulfur-Doped Carbon Nanotube-Graphene Nanolobes for Highly Efficient Oxygen Evolution and Reduction Catalysis

    SciTech Connect

    El-Sawy, Abdelhamid M.; Mosa, Islam M.; Su, Dong; Guild, Curtis J.; Khalid, Syed; Joesten, Raymond; Rusling, James F.; Suib, Steven L.

    2015-12-03

    Controlling active sites of metal-free catalysts is an important strategy to enhance activity of the oxygen evolution reaction (OER). We made many attempts have been made to develop metal-free catalysts, but the lack of understanding of active-sites at the atomic-level has slowed the design of highly active and stable metal-free catalysts. We also developed a sequential two-step strategy to dope sulfur into carbon nanotube–graphene nanolobes. This bidoping strategy introduces stable sulfur–carbon active-sites. Fluorescence emission of the sulfur K-edge by X-ray absorption near edge spectroscopy (XANES) and scanning transmission electron microscopy electron energy loss spectroscopy (STEM-EELS) mapping and spectra confirm that increasing the incorporation of heterocyclic sulfur into the carbon ring of CNTs not only enhances OER activity with an overpotential of 350 mV at a current density of 10 mA cm-2, but also retains 100% of stability after 75 h. Furthermore, the bidoped sulfur carbon nanotube–graphene nanolobes behave like the state-of-the-art catalysts for OER but outperform those systems in terms of turnover frequency (TOF) which is two orders of magnitude greater than (20% Ir/C) at 400 mV overpotential with very high mass activity 1000 mA cm-2 at 570 mV. Moreover, the sulfur bidoping strategy shows high catalytic activity for the oxygen reduction reaction (ORR). Stable bifunctional (ORR and OER) catalysts are low cost, and light-weight bidoped sulfur carbon nanotubes are potential candidates for next-generation metal-free regenerative fuel cells.

  16. Controlling the Active Sites of Sulfur-Doped Carbon Nanotube-Graphene Nanolobes for Highly Efficient Oxygen Evolution and Reduction Catalysis

    DOE PAGES

    El-Sawy, Abdelhamid M.; Mosa, Islam M.; Su, Dong; ...

    2015-12-03

    Controlling active sites of metal-free catalysts is an important strategy to enhance activity of the oxygen evolution reaction (OER). We made many attempts have been made to develop metal-free catalysts, but the lack of understanding of active-sites at the atomic-level has slowed the design of highly active and stable metal-free catalysts. We also developed a sequential two-step strategy to dope sulfur into carbon nanotube–graphene nanolobes. This bidoping strategy introduces stable sulfur–carbon active-sites. Fluorescence emission of the sulfur K-edge by X-ray absorption near edge spectroscopy (XANES) and scanning transmission electron microscopy electron energy loss spectroscopy (STEM-EELS) mapping and spectra confirm thatmore » increasing the incorporation of heterocyclic sulfur into the carbon ring of CNTs not only enhances OER activity with an overpotential of 350 mV at a current density of 10 mA cm-2, but also retains 100% of stability after 75 h. Furthermore, the bidoped sulfur carbon nanotube–graphene nanolobes behave like the state-of-the-art catalysts for OER but outperform those systems in terms of turnover frequency (TOF) which is two orders of magnitude greater than (20% Ir/C) at 400 mV overpotential with very high mass activity 1000 mA cm-2 at 570 mV. Moreover, the sulfur bidoping strategy shows high catalytic activity for the oxygen reduction reaction (ORR). Stable bifunctional (ORR and OER) catalysts are low cost, and light-weight bidoped sulfur carbon nanotubes are potential candidates for next-generation metal-free regenerative fuel cells.« less

  17. Sulfur-doped ordered mesoporous carbons: A stability-improving sulfur host for lithium-sulfur battery cathodes

    NASA Astrophysics Data System (ADS)

    Nitze, Florian; Fossum, Kjell; Xiong, Shizhao; Matic, Aleksandar; Palmqvist, Anders E. C.

    2016-06-01

    We report on sulfur-functionalized ordered mesoporous carbons aimed for lithium-sulfur battery electrode applications with improved charge capacity retention. The carbons were obtained by a hard-template strategy using a mixture of furfuryl alcohol and furfuryl mercaptan. For the application as electrode material in lithium-sulfur batteries, the carbons were additionally loaded with sulfur following a traditional melt-diffusion approach. It was found that the sulfur interacts stronger with the sulfur-functionalized carbon matrix than with the non-functionalized material. Electrodes showed very high capacity in the second discharge-charge cycle amounting to approximately 1500, 1200 and 1400 mAh/g (sulfur) for carbon materials with no, medium and high degrees of sulfur functionalization, respectively. More importantly, the sulfur-functionalization of the carbon was found to increase the capacity retention after 50 discharge-charge cycles by 8 and 5% for the carbons with medium and high degrees of sulfur-functionalization, respectively, compared to carbon with no sulfur-functionalization. We attribute this significant improvement to the presence of covalently bound sulfur groups at the internal surface of the functionalized carbon providing efficient anchoring sites for catenation to the sulfur loaded into the pores of the carbons and provide experimental support for this in the form of results from cyclic voltammetry and X-ray photoelectron spectroscopy.

  18. A flatter gallium profile for high-efficiency Cu(In,Ga)(Se,S)2 solar cell and improved robustness against sulfur-gradient variation

    NASA Astrophysics Data System (ADS)

    Huang, Chien-Yao; Lee, Wen-Chin; Lin, Albert

    2016-09-01

    . Finally, an exploratory path toward 20% high-efficiency Ga-profile with robustness against sulfur-induced performance variability is presented.

  19. Reduced graphene oxide with ultrahigh conductivity as carbon coating layer for high performance sulfur@reduced graphene oxide cathode

    NASA Astrophysics Data System (ADS)

    Zhao, Hongbin; Peng, Zhenhuan; Wang, Wenjun; Chen, Xikun; Fang, Jianhui; Xu, Jiaqiang

    2014-01-01

    We developed hydrogen iodide (HI) reduction of rGO and surfactant-assisted chemical reaction- deposition method to form hybrid material of sulfur (S) encapsulated in reduced graphene oxide (rGO) sheets for rechargeable lithium batteries. The surfactant-assisted chemical reaction-deposition method strategy provides intimate contact between the S and graphene oxide. Chemical reduced rGO with high conductivity as carbon coating layer prevented the dissolution of polysulfide ions and improved the electron transfer. This novel core-shell structured S@rGO composites with high S content showed high reversible capacity, good discharge capacity retention and enhanced rate capability used as cathodes in rechargeable Li/S cells. We demonstrated here that an electrode prepared from a S@rGO with up to 85 wt% S maintains a stable discharge capacity of about 980 mAh g-1 at 0.05 C and 570 mAh g-1 at 1C after 200 cycles charge/discharge. These results emphasize the importance of rGO with high electrical conductivity after HI-reduced rGO homogeneously coating on the surface of S, therefore, effectively alleviating the shuttle phenomenon of polysulfides in organic electrolyte. Our surfactant-assisted chemical reaction-HI reduction approach should offer a new technique for the design and synthesis of battery electrodes based on highly conducting carbon materials.

  20. Facile preparation of nitrogen/sulfur co-doped and hierarchical porous graphene hydrogel for high-performance electrochemical capacitor

    NASA Astrophysics Data System (ADS)

    Li, Jinhui; Zhang, Guoping; Fu, Chaopeng; Deng, Libo; Sun, Rong; Wong, Ching-Ping

    2017-03-01

    Nitrogen/sulfur co-doped and hierarchical porous graphene hydrogels (DHGHs) are prepared by facile self-assembly process. The results show that the pH values of preparation process significantly affect the microstructures and electrochemical properties of DHGHs and the mechanism has been discussed. The as-prepared DHGHs can be directly used as binder-free electrodes to assemble full-cell supercapacitor devices. It is surprising that the DHGHs prepared at basic condition (DHGH-12) delivers a specific capacitance of 251 F g-1 (0.5 A g-1). Moreover, the DHGH-12 shows rectangular cyclic voltammetry shape at a high scan rate of 3000 mV s-1 and symmetrical galvanostatic charge/discharge curves at 100 A g-1 which exhibits a specific capacitance of 136.5 F g-1, a high energy density of 4.74 Wh kg-1 and high power density of 25.47 kW kg-1. Additionally, DHGH-12 presents superior cycling stability (96.8% retention after 2000 cycles at 20 A g-1) in 6 M KOH solution. Therefore, the novel DHGHs can be considered as promising candidate for high energy density supercapacitors at high rates.

  1. Sulfuric acid doped poly diaminopyridine/graphene composite to remove high concentration of toxic Cr(VI).

    PubMed

    Dinda, Diptiman; Kumar Saha, Shyamal

    2015-06-30

    Sulfuric acid doped diaminopyridine polymers are synthesized in situ on graphene oxide surface via mutual oxidation-reduction technique. Exploiting large and highly porous surface, we have used this polymer composite as an adsorbent to remove high concentration of toxic Cr(VI) from water. It shows very high adsorption capacity (609.76 mg g(-1)) during removal process. The composite takes only 100 min to remove high concentration of 500 mg L(-1) Cr(VI) from water. Interesting features for this material is the enhancement of removal efficiency at lower acidic condition due to the formation of acid doped emeraldine salt during polymerization. XPS and AAS measurements reveal that our prepared material mainly follows reduction mechanism at higher acidic condition while anions exchange mechanism at lower acidic condition during the removal experiments. Good recycling ability with ∼ 92% removal efficiency after fifth cycle is also noticed for this material. Easy preparation, superior stability in acidic condition, remarkable removal efficiency and excellent recycling ability make this polymer composite an efficient material for modern filtration units in waste water purification.

  2. Honeysuckle-derived hierarchical porous nitrogen, sulfur, dual-doped carbon for ultra-high rate lithium ion battery anodes

    NASA Astrophysics Data System (ADS)

    Ou, Junke; Yang, Lin; Zhang, Zhen; Xi, Xianghui

    2016-11-01

    Nowadays, developing functional carbon materials from cheap natural materials is a highly compelling topic. Different from most explored biomass, honeysuckle is inherently rich in nitrogen and sulfur heteroatoms, and it has many advantages for production on a large scale. Here, hierarchical porous carbon (HPC), derived from waste honeysuckle via an environmentally friendly and economically viable method, has been reported as an anode for rechargeable lithium ion batteries. The as-fabricated HPC exhibits favorable features for electrochemical energy storage performance such as high specific surface area (830 m2 g-1), hierarchical three-dimensional (3D) pore network and heteroatoms (N and S) doping effects. HPC, when evaluated as an anode material for lithium ion batteries, shows superior cycling stability (maintaining a reversible capacity of 1215 mAh g-1 at the current density of 100 mA g-1 after 100 cycles) and excellent rate capability (370 mAh g-1 at the current density of 20 A g-1). Furthermore, owing to the appropriate heteroatoms doping, a high initial coulombic efficiency of 64.7% can be achieved. A widespread comparison with the literature also showed that the honeysuckle derived porous carbon was one of the most promising carbon-based anodes for high-rate lithium ion batteries.

  3. Arsenic trioxide prevents nitric oxide production in lipopolysaccharide -stimulated RAW 264.7 by inhibiting a TRIF-dependent pathway.

    PubMed

    Takahashi, Miyuki; Ota, Akinobu; Karnan, Sivasundaram; Hossain, Ekhtear; Konishi, Yuko; Damdindorj, Lkhagvasuren; Konishi, Hiroyuki; Yokochi, Takashi; Nitta, Masakazu; Hosokawa, Yoshitaka

    2013-02-01

    Arsenic trioxide (ATO) is one of the most potent drugs in cancer chemotherapy, and is highly effective in treating both newly diagnosed and relapse patients with acute promyelocytic leukemia (APL). Despite a number of reports regarding the molecular mechanisms by which ATO promotes anti-tumor or pro-apoptotic activity in hematological and other solid malignancies, the effects of ATO on immune responses remain poorly understood. To further understand and clarify the effects of ATO on immune responses, we sought to examine whether ATO affects the production of nitric oxide (NO) in a lipopolysaccharide (LPS)-stimulated mouse macrophage cell line, RAW 264.7. Arsenic trioxide was found to prevent NO production in a dose-dependent manner. Arsenic trioxide significantly inhibited the increase in inducible nitric oxide synthase (iNOS) at both the mRNA and protein levels. Furthermore, our analyses revealed that the inhibitory effect of ATO on iNOS expression was ascribed to the prevention of IRF3 phosphorylation, interferon (IFN)-β expression, and STAT1 phosphorylation, but not the prevention of the MyD88-dependent pathway. Taken together, our results indicate that ATO prevents NO production by inhibiting the TIR-domain-containing adaptor protein inducing IFN-β (TRIF)-dependent pathway, thus highlighting an anti-inflammatory property of ATO in innate immunity.

  4. Strong Lithium Polysulfide Chemisorption on Electroactive Sites of Nitrogen-Doped Carbon Composites For High-Performance Lithium-Sulfur Battery Cathodes

    SciTech Connect

    Song, Jiangxuan; Gordin, Mikhail L.; Xu, Terrence; Chen, Shuru; Yu, Zhaoxin; Sohn, Hiesang; Lu, Jun; Ren, Yang; Duan, Yuhua; Wang, Donghai

    2015-03-27

    Despite the high theoretical capacity of lithium–sulfur batteries, their practical applications are severely hindered by a fast capacity decay, stemming from the dissolution and diffusion of lithium polysulfides in the electrolyte. A novel functional carbon composite (carbon-nanotube-interpenetrated mesoporous nitrogen-doped carbon spheres, MNCS/CNT), which can strongly adsorb lithium polysulfides, is now reported to act as a sulfur host. The nitrogen functional groups of this composite enable the effective trapping of lithium polysulfides on electroactive sites within the cathode, leading to a much improved electrochemical performance (1200 mAhg-1after 200 cycles). The enhancement in adsorption can be attributed to the chemical bonding of lithium ions by nitrogen functional groups in the MNCS/CNT framework. Furthermore, the micrometer-sized spherical structure of the material yields a high areal capacity (ca.6 mAhcm-2) with a high sulfur loading of approximately 5 mgcm-2, which is ideal for practical applications of the lithium–sulfur batteries.

  5. Strong Lithium Polysulfide Chemisorption on Electroactive Sites of Nitrogen-Doped Carbon Composites For High-Performance Lithium–Sulfur Battery Cathodes

    SciTech Connect

    Song, Jiangxuan; Gordin, Mikhail; Xu, Terrence; Chen, Shuru; Yu, Zhaoxin; Sohn, Hiesang; Lu, Jun; Ren, Yang; Duan, Yuhua; wang, Donghai

    2015-03-27

    Despite the high theoretical capacity of lithium–sulfur batteries, their practical applications are severely hindered by a fast capacity decay, stemming from the dissolution and diffusion of lithium polysulfides in the electrolyte. A novel functional carbon composite (carbon-nanotube-interpenetrated mesoporous nitrogen-doped carbon spheres, MNCS/CNT), which can strongly adsorb lithium polysulfides, is now reported to act as a sulfur host. The nitrogen functional groups of this composite enable the effective trapping of lithium polysulfides on electroactive sites within the cathode, leading to a much improved electrochemical performance (1200 mAh g-1 after 200 cycles). The enhancement in adsorption can be attributed to the chemical bonding of lithium ions by nitrogen functional groups in the MNCS/CNT framework. Furthermore, the micrometer-sized spherical structure of the material yields a high areal capacity (ca. 6 mAh cm-2) with a high sulfur loading of approximately 5 mg cm-2, which is ideal for practical applications of the lithium–sulfur batteries.

  6. Evidence of covalent synergy in silicon-sulfur-graphene yielding highly efficient and long-life lithium-ion batteries.

    PubMed

    Hassan, Fathy M; Batmaz, Rasim; Li, Jingde; Wang, Xiaolei; Xiao, Xingcheng; Yu, Aiping; Chen, Zhongwei

    2015-10-26

    Silicon has the potential to revolutionize the energy storage capacities of lithium-ion batteries to meet the ever increasing power demands of next generation technologies. To avoid the operational stability problems of silicon-based anodes, we propose synergistic physicochemical alteration of electrode structures during their design. This capitalizes on covalent interaction of Si nanoparticles with sulfur-doped graphene and with cyclized polyacrylonitrile to provide a robust nanoarchitecture. This hierarchical structure stabilized the solid electrolyte interphase leading to superior reversible capacity of over 1,000 mAh g(-1) for 2,275 cycles at 2 A g(-1). Furthermore, the nanoarchitectured design lowered the contact of the electrolyte to the electrode leading to not only high coulombic efficiency of 99.9% but also maintaining high stability even with high electrode loading associated with 3.4 mAh cm(-2). The excellent performance combined with the simplistic, scalable and non-hazardous approach render the process as a very promising candidate for Li-ion battery technology.

  7. A novel quasi-solid state electrolyte with highly effective polysulfide diffusion inhibition for lithium-sulfur batteries

    PubMed Central

    Zhong, Hai; Wang, Chunhua; Xu, Zhibin; Ding, Fei; Liu, Xinjiang

    2016-01-01

    Polymer solid state electrolytes are actively sought for their potential application in energy storage devices, particularly lithium metal rechargeable batteries. Herein, we report a polymer with high concentration salts as a quasi-solid state electrolyte used for lithium-sulfur cells, which shows an ionic conductivity of 1.6 mS cm−1 at room temperature. The cycling performance of Li-S battery with this electrolyte shows a long cycle life (300 cycles) and high coulombic efficiency (>98%), without any consuming additives in the electrolyte. Moreover, it also shows a remarkably decreased self-discharge (only 0.2%) after storage for two weeks at room temperature. The reason can be attributed to that the electrolyte can suppress polysulfide anions diffusion, due to the high ratio oxygen atoms with negative charges which induce an electrical repulsion to the polysulfide anions, and their relatively long chains which can provide additional steric hindrance. Thus, the polysulfide anions can be located around carbon particles, which result in remarkably improved overall electrochemical performance, and also the electrolyte have a function of suppress the formation of lithium dendrites on the lithium anode surface. PMID:27146645

  8. Evidence of covalent synergy in silicon-sulfur-graphene yielding highly efficient and long-life lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Hassan, Fathy M.; Batmaz, Rasim; Li, Jingde; Wang, Xiaolei; Xiao, Xingcheng; Yu, Aiping; Chen, Zhongwei

    2015-10-01

    Silicon has the potential to revolutionize the energy storage capacities of lithium-ion batteries to meet the ever increasing power demands of next generation technologies. To avoid the operational stability problems of silicon-based anodes, we propose synergistic physicochemical alteration of electrode structures during their design. This capitalizes on covalent interaction of Si nanoparticles with sulfur-doped graphene and with cyclized polyacrylonitrile to provide a robust nanoarchitecture. This hierarchical structure stabilized the solid electrolyte interphase leading to superior reversible capacity of over 1,000 mAh g-1 for 2,275 cycles at 2 A g-1. Furthermore, the nanoarchitectured design lowered the contact of the electrolyte to the electrode leading to not only high coulombic efficiency of 99.9% but also maintaining high stability even with high electrode loading associated with 3.4 mAh cm-2. The excellent performance combined with the simplistic, scalable and non-hazardous approach render the process as a very promising candidate for Li-ion battery technology.

  9. A novel quasi-solid state electrolyte with highly effective polysulfide diffusion inhibition for lithium-sulfur batteries

    NASA Astrophysics Data System (ADS)

    Zhong, Hai; Wang, Chunhua; Xu, Zhibin; Ding, Fei; Liu, Xinjiang

    2016-05-01

    Polymer solid state electrolytes are actively sought for their potential application in energy storage devices, particularly lithium metal rechargeable batteries. Herein, we report a polymer with high concentration salts as a quasi-solid state electrolyte used for lithium-sulfur cells, which shows an ionic conductivity of 1.6 mS cm‑1 at room temperature. The cycling performance of Li-S battery with this electrolyte shows a long cycle life (300 cycles) and high coulombic efficiency (>98%), without any consuming additives in the electrolyte. Moreover, it also shows a remarkably decreased self-discharge (only 0.2%) after storage for two weeks at room temperature. The reason can be attributed to that the electrolyte can suppress polysulfide anions diffusion, due to the high ratio oxygen atoms with negative charges which induce an electrical repulsion to the polysulfide anions, and their relatively long chains which can provide additional steric hindrance. Thus, the polysulfide anions can be located around carbon particles, which result in remarkably improved overall electrochemical performance, and also the electrolyte have a function of suppress the formation of lithium dendrites on the lithium anode surface.

  10. Advanced sulfur control concepts

    SciTech Connect

    Harrison, D.P.; Lopez-Ortiz, A.; White, J.D.; Groves, F.R. Jr.

    1995-11-01

    The primary objective of this study is the direct production of elemental sulfur during the regeneration of high temperature desulfurization sorbents. Three possible regeneration concepts were identified as a result of a literature search. The potential for elemental sulfur production from a number of candidate metal oxide sorbents using each regeneration concept was evaluated on the basis of a thermodynamic analysis. Two candidate sorbents, Fe{sub 2}O{sub 3} and CeO{sub 2} were chosen for experimental testing. The experimental test program using both electrobalance and fixed-bed reactor sis now getting underway. The objective is to determine reaction conditions--temperature, pressure, space velocity, and regeneration feed gas composition--which will maximize the yield of elemental sulfur in the regeneration product gas. Experimental results are to be used to define a conceptual desulfurization-regeneration process and to provide a preliminary economic evaluation.

  11. Have all-trans retinoic acid and arsenic trioxide replaced all-trans retinoic acid and anthracyclines in APL as standard of care.

    PubMed

    Iland, Harry J; Wei, Andrew; Seymour, John F

    2014-03-01

    Until recently, the standard of care in the treatment of APL has involved the combination of all-trans retinoic acid with anthracycline-based chemotherapy during both induction and consolidation. Additionally, the intensity of consolidation chemotherapy has evolved according to a universally accepted relapse-risk stratification algorithm based on the white cell and platelet counts at presentation. That standard of care is being challenged by the increasing incorporation of arsenic trioxide into front-line treatment protocols, based on two complementary observations. The first is the undoubted anti-leukaemic activity of arsenic trioxide as shown in the relapsed and refractory setting, and in the initial management of low- and intermediate-risk patients. The second is an improved understanding of the action of both all-trans retinoic acid and arsenic trioxide in mediating APL cell eradication, with increasing recognition that PML-RARA fusion protein degradation rather than direct induction of terminal differentiation is the primary mechanism for their ability to eliminate leukaemia initiating cells. As a result, we believe the standard of care for initial therapy in APL is shifting towards an all-trans retinoic acid plus arsenic trioxide-based approach, with additional chemotherapy reserved for patients with high-risk disease.

  12. Two stage sorption of sulfur compounds

    DOEpatents

    Moore, William E.

    1992-01-01

    A two stage method for reducing the sulfur content of exhaust gases is disclosed. Alkali- or alkaline-earth-based sorbent is totally or partially vaporized and introduced into a sulfur-containing gas stream. The activated sorbent can be introduced in the reaction zone or the exhaust gases of a combustor or a gasifier. High efficiencies of sulfur removal can be achieved.

  13. Near-Zero Emissions Oxy-Combustion Flue Gas Purification Task 2: SOx/Nox/Hg Removal for High Sulfur Coal

    SciTech Connect

    Nick Degenstein; Minish Shah; Doughlas Louie

    2012-05-01

    The goal of this project is to develop a near-zero emissions flue gas purification technology for existing PC (pulverized coal) power plants that are retrofitted with oxy-combustion technology. The objective of Task 2 of this project was to evaluate an alternative method of SOx, NOx and Hg removal from flue gas produced by burning high sulfur coal in oxy-combustion power plants. The goal of the program was not only to investigate a new method of flue gas purification but also to produce useful acid byproduct streams as an alternative to using a traditional FGD and SCR for flue gas processing. During the project two main constraints were identified that limit the ability of the process to achieve project goals. 1) Due to boiler island corrosion issues >60% of the sulfur must be removed in the boiler island with the use of an FGD. 2) A suitable method could not be found to remove NOx from the concentrated sulfuric acid product, which limits sale-ability of the acid, as well as the NOx removal efficiency of the process. Given the complexity and safety issues inherent in the cycle it is concluded that the acid product would not be directly saleable and, in this case, other flue gas purification schemes are better suited for SOx/NOx/Hg control when burning high sulfur coal, e.g. this project's Task 3 process or a traditional FGD and SCR.

  14. HIGH ARSENIC CONCENTRATIONS AND ENRICHED SULFUR AND OXYGEN ISOTOPES IN A FRACTURED-BEDROCK GROUND-WATER SYSTEM

    EPA Science Inventory

    Elevated arsenic concentrations are coincident with enriched sulfur and oxygen isotopes of sulfate in bedrock ground water within Kelly's Cove watershed, Northport, Maine, USA. Interpretation of the data is complicated by the lack of correlations between sulfate concentrations an...

  15. Mineral trioxide aggregate (MTA): its history, composition, and clinical applications.

    PubMed

    Tawil, Peter Z; Duggan, Derek J; Galicia, Johnah C

    2015-04-01

    Mineral trioxide aggregate (MTA) has been a revolutionary material in endodontics. Since its introduction in the 1990s several studies have demonstrated its use in various clinical applications. MTA has been extensively studied and is currently used for perforation repairs, apexifications, regenerative procedures, apexogenesis, pulpotomies, and pulp capping. This article will review the history, composition, research findings, and clinical applications of this versatile endodontic material.

  16. High yield production of sugars from deproteinated palm kernel cake under microwave irradiation via dilute sulfuric acid hydrolysis.

    PubMed

    Fan, Suet-Pin; Jiang, Li-Qun; Chia, Chin-Hua; Fang, Zhen; Zakaria, Sarani; Chee, Kah-Leong

    2014-02-01

    Recent years, great interest has been devoted to the conversion of biomass-derived carbohydrate into sugars, such as glucose, mannose and fructose. These are important versatile intermediate products that are easily processed into high value-added biofuels. In this work, microwave-assisted dilute sulfuric acid hydrolysis of deproteinated palm kernel cake (DPKC) was systematically studied using Response Surface Methodology. The highest mannose yield (92.11%) was achieved at the optimized condition of 148°C, 0.75N H2SO4, 10min 31s and substrate to solvent (SS) ratio (w/v) of 1:49.69. Besides that, total fermentable sugars yield (77.11%), was obtained at 170°C, 0.181N H2SO4, 6min 6s and SS ratio (w/v) of 1:40. Ridge analysis was employed to further verify the optimum conditions. Thus, this work provides fundamental data of the practical use of DPKC as low cost, high yield and environmental-friendly material for the production of mannose and other sugars.

  17. Density and Sound Velocity of Iron-Sulfur Alloying Liquids at High Pressures and Implications to Planetary Cores

    SciTech Connect

    Jing, Z.; Wang, Y.; Yu, T.; Sakamaki, T.; Kono, Y.; Park, C.

    2012-04-30

    Liquid Fe-light element alloys are likely present in the Earth's outer core and the cores (or outer cores) of other terrestrial planets such as Moon, Mercury, and Mars, suggested by geophysical and geochemical observations. In order to determine the abundances of light elements and their effects on the structure, dynamics, and evolution of planetary cores, it is crucial to determine the equation of state for Fe-light element alloying liquids under core conditions. However, density data on liquid Fe-light element alloys at core pressures are very limited and no sound velocity or bulk modulus data are available for these liquids at high pressures. This makes it difficult to extrapolate the equation of state to core pressures. As a result, density data on solid Fe alloys are often used in the literature to compare with seismological observations by making rough corrections for the volume of melting. In this study, we determine the density and sound velocity for Fe-S liquids with different sulfur contents at high pressure and temperature conditions up to 8 GPa and 2173 K using synchrotron X-ray techniques.

  18. Vapor-phase atomic-controllable growth of amorphous Li2S for high-performance lithium-sulfur batteries.

    PubMed

    Meng, Xiangbo; Comstock, David J; Fister, Timothy T; Elam, Jeffrey W

    2014-10-28

    Lithium-sulfur (Li-S) batteries hold great promise to meet the formidable energy storage requirements of future electrical vehicles but are prohibited from practical implementation by their severe capacity fading and the risks imposed by Li metal anodes. Nanoscale Li(2)S offers the possibility to overcome these challenges, but no synthetic technique exists for fine-tailoring Li(2)S at the nanoscale. Herein we report a vapor-phase atomic layer deposition (ALD) method for the atomic-scale-controllable synthesis of Li(2)S. Besides a comprehensive investigation of the ALD Li(2)S growth mechanism, we further describe the high performance of the resulting amorphous Li(2)S nanofilms as cathodes in Li-S batteries, achieving a stable capacity of ∼ 800 mA · h/g, nearly 100% Coulombic efficiency, and excellent rate capability. Nanoscale Li(2)S holds great potential for both bulk-type and thin-film high-energy Li-S batteries.

  19. High dietary sulfur decreases the retention of copper, manganese, and zinc in steers.

    PubMed

    Pogge, D J; Drewnoski, M E; Hansen, S L

    2014-05-01

    To examine the effects of dietary S on diet digestibility and apparent mineral absorption and retention, 16 steers [8 ruminally fistulated (368 ± 12 kg BW) and 8 unmodified (388 ± 10 kg BW)] were paired within modification status and BW, and within each of the 2 consecutive 28-d periods, 4 pairs of steers were randomly assigned to either a low-S (0.24%) or high-S (0.68%) pelleted diet. Bromegrass hay was fed at 5 or 7% of the diet, during periods 1 and 2, respectively. Sodium sulfate was used to increase the S content of the high-S diet. The low-S steers were fed the amount of feed their high-S counterpart consumed the previous day, while the high-S steers received 110% of the previous day's intake. Steers were adapted to individual metabolism stalls for 4 d (d -3 to 0 of period), acclimated to diet for 7 d (d 1 to 7 of period), and after high-S steers were consuming ad libitum intake for 7 d (d 14 of period), total urine and feces were collected for 5 d. Feed intake and orts were recorded daily. Dry matter and OM digestibility were determined. Jugular blood was collected before and after each collection period on d 14 and 20, and liver biopsies were collected on d 0 and 27. Macromineral (Ca, K, Mg, and Na) and micromineral (Cu, Mn, and Zn) concentrations were determined for pellets and hay, orts, feces, urine, and plasma and liver samples from each steer via inductively coupled plasma spectrometry. Dry matter intake, DM and OM digestibility, and urine volume were not affected (P ≥ 0.11) by dietary treatment, but fecal output was greater (P = 0.02) in the low-S steers than the high-S steers. A high-S diet decreased plasma Cu (P = 0.04) and liver Zn (P = 0.03) compared to low-S steers. No differences (P ≥ 0.20) were noted among urinary excretion of Cu, Mn, and Zn. Sodium absorption was greater (P < 0.01) and Cu, Mn, and Zn retention was lesser (P ≤ 0.01) in the high-S steers than the low-S steers. Apparent absorption of Ca, K, and Mg was not affected (P

  20. High Purity Hydrogen Production with In-Situ Carbon Dioxide and Sulfur Capture in a Single Stage Reactor

    SciTech Connect

    Nihar Phalak; Shwetha Ramkumar; Daniel Connell; Zhenchao Sun; Fu-Chen Yu; Niranjani Deshpande; Robert Statnick; Liang-Shih Fan

    2011-07-31

    Enhancement in the production of high purity hydrogen (H{sub 2}) from fuel gas, obtained from coal gasification, is limited by thermodynamics of the water gas shift (WGS) reaction. However, this constraint can be overcome by conducting the WGS in the presence of a CO{sub 2}-acceptor. The continuous removal of CO{sub 2} from the reaction mixture helps to drive the equilibrium-limited WGS reaction forward. Since calcium oxide (CaO) exhibits high CO{sub 2} capture capacity as compared to other sorbents, it is an ideal candidate for such a technique. The Calcium Looping Process (CLP) developed at The Ohio State University (OSU) utilizes the above concept to enable high purity H{sub 2} production from synthesis gas (syngas) derived from coal gasification. The CLP integrates the WGS reaction with insitu CO{sub 2}, sulfur and halide removal at high temperatures while eliminating the need for a WGS catalyst, thus reducing the overall footprint of the hydrogen production process. The CLP comprises three reactors - the carbonator, where the thermodynamic constraint of the WGS reaction is overcome by the constant removal of CO{sub 2} product and high purity H{sub 2} is produced with contaminant removal; the calciner, where the calcium sorbent is regenerated and a sequestration-ready CO{sub 2} stream is produced; and the hydrator, where the calcined sorbent is reactivated to improve its recyclability. As a part of this project, the CLP was extensively investigated by performing experiments at lab-, bench- and subpilot-scale setups. A comprehensive techno-economic analysis was also conducted to determine the feasibility of the CLP at commercial scale. This report provides a detailed account of all the results obtained during the project period.

  1. Rational Design of Cathode Structure for High Rate Performance Lithium-Sulfur Batteries.

    PubMed

    Chen, Hongwei; Wang, Changhong; Dai, Yafei; Qiu, Shengqiang; Yang, Jinlong; Lu, Wei; Chen, Liwei

    2015-08-12

    Practical applications of Li-S batteries require not only high specific capacities and long cycle lifetimes but also high rate performance. We report a rationally designed Li-S cathode, which consists of a freestanding composite thin film assembled from S nanoparticles, reduced graphene oxide (rGO), and a multifunctional additive poly(anthraquinonyl sulfide) (PAQS). The S nanoparticles provide a high initial specific capacity, and the layered and porous rGO structure provides electron and ion transport paths and restricts polysulfide shuttling. PAQS is not only a highly efficient sulfide trapping agent but also an excellent Li(+) conductor, which benefits the battery reaction kinetics at a high rate. The resulting cathode exhibits an initial specific capacity of 1255 mAh g(-1) with a decay rate as low as 0.046% per cycles over 1200 cycles. Importantly, it displays a reversible capacity of 615 mAh g(-1) when discharged at a high rate of 8 C (13.744 A g(-1)).

  2. High-rate, ultralong cycle-life lithium/sulfur batteries enabled by nitrogen-doped graphene.

    PubMed

    Qiu, Yongcai; Li, Wanfei; Zhao, Wen; Li, Guizhu; Hou, Yuan; Liu, Meinan; Zhou, Lisha; Ye, Fangmin; Li, Hongfei; Wei, Zhanhua; Yang, Shihe; Duan, Wenhui; Ye, Yifan; Guo, Jinghua; Zhang, Yuegang

    2014-08-13

    Nitrogen-doped graphene (NG) is a promising conductive matrix material for fabricating high-performance Li/S batteries. Here we report a simple, low-cost, and scalable method to prepare an additive-free nanocomposite cathode in which sulfur nanoparticles are wrapped inside the NG sheets (S@NG). We show that the Li/S@NG can deliver high specific discharge capacities at high rates, that is, ∼ 1167 mAh g(-1) at 0.2 C, ∼ 1058 mAh g(-1) at 0.5 C, ∼ 971 mAh g(-1) at 1 C, ∼ 802 mAh g(-1) at 2 C, and ∼ 606 mAh g(-1) at 5 C. The cells also demonstrate an ultralong cycle life exceeding 2000 cycles and an extremely low capacity-decay rate (0.028% per cycle), which is among the best performance demonstrated so far for Li/S cells. Furthermore, the S@NG cathode can be cycled with an excellent Coulombic efficiency of above 97% after 2000 cycles. With a high active S content (60%) in the total electrode weight, the S@NG cathode could provide a specific energy that is competitive to the state-of-the-art Li-ion cells even after 2000 cycles. The X-ray spectroscopic analysis and ab initio calculation results indicate that the excellent performance can be attributed to the well-restored C-C lattice and the unique lithium polysulfide binding capability of the N functional groups in the NG sheets. The results indicate that the S@NG nanocomposite based Li/S cells have a great potential to replace the current Li-ion batteries.

  3. Sulfur passivation of surface electrons in highly Mg-doped InN

    NASA Astrophysics Data System (ADS)

    Linhart, W. M.; Chai, J.; McConville, C. F.; Durbin, S. M.; Veal, T. D.

    2013-09-01

    Electron accumulation with a sheet density greater than 1013 cm-2 usually occurs at InN surfaces. Here, the effects of treatment with ammonium sulfide ((NH4)2Sx) on the surface electronic properties of highly Mg-doped InN (>4×1018 cm-3) have been investigated with high resolution x-ray photoemission spectroscopy. The valence band photoemission spectra show that the surface Fermi level decreases by approximately 0.08 eV with (NH4)2Sx treatment, resulting in a decrease of the downward band bending and up to a 70% reduction in the surface electron sheet density.

  4. Sulfur speciation with high performance liquid chromatography as a tool for El Chichón volcano, crater lake monitoring

    NASA Astrophysics Data System (ADS)

    Casas, Ana Silvia; Armienta, María Aurora; Ramos, Silvia

    2016-12-01

    The monitoring of sulfur species in crater lakes has proven to be useful for forecasting episodes of volcanic unrest in certain active volcanoes, including Poás, Costa Rica; Kusatsu-Shirane, Japan; and Mt. Ruapehu, New Zealand. In this study, we have improved the current geochemical monitoring of El Chichón volcano through the setting of optimal high-performance liquid chromatography conditions (HPLC) for the analysis of S2-, SO32-, S2O32-, S4O62- and SO42- using a common chromatographic system. The procedure was applied to the analysis of lake samples taken in March, July and October of 2014 and April of 2015. The results were promising, since nearly all species were detected (with the exception of S2O32-) in measurable amounts, including S2- (<0.85-5.05 mg/L), SO32- (<2.77-26.1 mg/L), S4O62- (108.27-303.82 mg/L) and SO42- (489.58-676.26 mg/L). The spatial distribution of these species along the lakeshore showed zones of increased concentrations to the east and southeast of the lake, which provides information on the distribution of faults or cracks that feed hydrothermal fluids to the lake. This method thus provides additional information linked to the volcanic and hydrothermal activity of the volcano.

  5. Stable sulfur isotopes identify habitat-specific foraging and mercury exposure in a highly mobile fish community.

    PubMed

    Carr, Meghan K; Jardine, Timothy D; Doig, Lorne E; Jones, Paul D; Bharadwaj, Lalita; Tendler, Brett; Chételat, John; Cott, Pete; Lindenschmidt, Karl-Erich

    2017-02-10

    Tracking the uptake and transfer of toxic chemicals, such as mercury (Hg), in aquatic systems is challenging when many top predators are highly mobile and may therefore be exposed to chemicals in areas other than their location of capture, confounding interpretation of bioaccumulation trends. Here we show how the application of a less commonly used ecological tracer, stable sulfur isotope ratios ((34)S/(32)S, or δ(34)S), in a large river-delta-lake complex in northern Canada allows differentiation of resident from migrant fishes, beyond what was possible with more conventional (13)C/(12)C and (15)N/(14)N measurements. Though all large fishes (n=105) were captured in the river, the majority (76%) had δ(34)S values that were indicative of the fish having been reared in the lake. These migrant fishes were connected to a food chain with greater Hg trophic magnification relative to the resident fish of the river and delta. Yet, despite a shallower overall trophic magnification slope, large river-resident fish had higher Hg concentrations owing to a greater biomagnification of Hg between small and large fishes. These findings reveal how S isotopes can trace fish feeding habitats in large freshwater systems and better account for fish movement in complex landscapes with differential exposure pathways and conditions.

  6. Sulfur-oxidizing bacteria in Soap Lake (Washington State), a meromictic, haloalkaline lake with an unprecedented high sulfide content.

    PubMed

    Sorokin, Dimitry Y; Foti, Mirjam; Pinkart, Holly C; Muyzer, Gerard

    2007-01-01

    Culture-dependent and -independent techniques were used to study the diversity of chemolithoautotrophic sulfur-oxidizing bacteria in Soap Lake (Washington State), a meromictic, haloalkaline lake containing an unprecedentedly high sulfide concentration in the anoxic monimolimnion. Both approaches revealed the dominance of bacteria belonging to the genus Thioalkalimicrobium, which are common inhabitants of soda lakes. A dense population of Thioalkalimicrobium (up to 10(7) cells/ml) was found at the chemocline, which is characterized by a steep oxygen-sulfide gradient. Twelve Thioalkalimicrobium strains exhibiting three different phenotypes were isolated in pure culture from various locations in Soap Lake. The isolates fell into two groups according to 16S rRNA gene sequence analysis. One of the groups was closely related to T. cyclicum, which was isolated from Mono Lake (California), a transiently meromictic, haloalkaline lake. The second group, consisting of four isolates, was phylogenetically and phenotypically distinct from known Thioalkalimicrobium species and unique to Soap Lake. It represented a new species, for which we suggest the name Thioalkalimicrobium microaerophilum sp. nov.

  7. A highly selective sulfur-free iridium(III)-complex-based phosphorescent chemidosimeter for detection of mercury(II) ions.

    PubMed

    Zeng, Hui; Yu, Fang; Dai, Jun; Sun, Huiqin; Lu, Zhiyun; Li, Ming; Jiang, Qing; Huang, Yan

    2012-04-28

    A neutral phosphorescent coordination compound bearing a benzimidazole ligand, Ir(pbi)(2)(acac) (Hpbi = 1,2-diphenyl-1H-benzo[d]imidazole; Hacac = acetylacetone), is demonstrated to be the first example of a sulfur-free iridium complex for the detection of Hg(2+) cations with high selectivity and sensitivity. Ir(pbi)(2)(acac) shows a multisignaling response towards mercury(II) ions through UV-vis absorption, phosphorescence and electrochemistry measurements. Upon addition of Hg(2+) ions, solutions of this complex change from yellow to colorless, which could be observed easily by the naked eye, while its phosphorescence turns from bright green (λ(PLmax) = 520 nm) into faint skyblue (λ(PLmax) = 476 nm), and the detection limit is calculated to be 2.4 × 10(-7) mol L(-1). (1)H NMR spectroscopic titration as well as ESI-MS results indicate that the decomposition of Ir(pbi)(2)(acac) in the presence of Hg(2+) through rupture of Ir-O bonds is responsible for the significant variations in both optical and electrochemical signals.

  8. Sulfur-doped graphene quantum dots as a novel fluorescent probe for highly selective and sensitive detection of Fe(3+).

    PubMed

    Li, Shuhua; Li, Yunchao; Cao, Jun; Zhu, Jia; Fan, Louzhen; Li, Xiaohong

    2014-10-21

    Sulfur-doped graphene quantum dots (S-GQDs) with stable blue-green fluorescence were synthesized by one-step electrolysis of graphite in sodium p-toluenesulfonate aqueous solution. Compared with GQDs, the S-GQDs drastically improved the electronic properties and surface chemical reactivities, which exhibited a sensitive response to Fe(3+). Therefore, the S-GQDs were used as an efficient fluorescent probe for highly selective detection of Fe(3+). Upon increasing of Fe(3+) concentration ranging from 0.01 to 0.70 μM, the fluorescence intensity of S-GQDs gradually decreased and reached a plateau at 0.90 μM. The difference in the fluorescence intensity of S-GQDs before and after adding Fe(3+) was proportional to the concentration of Fe(3+), and the calibration curve displayed linear regions over the range of 0-0.70 μM. The detection limit was 4.2 nM. Finally, this novel fluorescent probe was successfully applied to the direct analysis of Fe(3+) in human serum, which presents potential applications in clinical diagnosis and may open a new way to the design of effective fluorescence probes for other biologically related targets.

  9. Economic evaluation of FGD systems. Volume 1. Throwaway FGD processes, high- and low-sulfur coal. Final report

    SciTech Connect

    Keeth, R.J.; Miranda, J.E.; Reisdorf, J.B.; Scheck, R.W.

    1983-12-01

    This volume presents the estimated cost for 10 throwaway FGD systems and a coal cleaning process based on December 1982 cost and technology. These systems were evaluated for operability, technical merit and commercial availability. The FGD systems were evaluated for both high and low sulfur coal applications at a hypothetical 1000 MW (two 500 MW units) power plant in Kenosha, Wisconsin. This arbitrary reference plant was selected to ensure consistent comparisons, and to increase the relative accuracy of the costs presented. A flow sheet, material balance, equipment list, system description and utility consumption list form the basis of each FGD evaluation. Cost information was obtained from process vendors, Stearns-Roger information, and published reports. Capital costs were estimated by factoring costs of process equipment (i.e., an EPRI Class II estimate.) Operating costs were estimated from reagent and utility consumption. The levelized capital and operating costs were developed using EPRI's standard economic premises. Costs have an absolute accuracy of +-30 percent. However, since methodology, scope and unit costs are consistent, the relative accuracy between process estimates probably is +-15 percent.

  10. Geochemistry of redox-sensitive elements and sulfur isotopes in the high arsenic groundwater system of Datong Basin, China.

    PubMed

    Xie, Xianjun; Ellis, Andre; Wang, Yanxin; Xie, Zuoming; Duan, Mengyu; Su, Chunli

    2009-06-01

    High arsenic groundwater in the Quaternary aquifers of Datong Basin, northern China contain As up to 1820 microg/L and the high concentration plume is located in the slow flowing central parts of the basin. In this study we used hydrochemical data and sulfur isotope ratios of sulfate to better understand the conditions that are likely to control arsenic mobilization. Groundwater and spring samples were collected along two flow paths from the west and east margins of the basin and a third set along the basin flow path. Arsenic concentrations range from 68 to 670 microg/L in the basin and from 3.1 to 44 microg/L in the western and eastern margins. The margins have relatively oxidized waters with low contents of arsenic, relatively high proportions of As(V) among As species, and high contents of sulfate and uranium. By contrast, the central parts of the basin are reducing with high contents of arsenic in groundwater, commonly with high proportions of As(III) among As species, and low contents of sulfate and uranium. No statistical correlations were observed between arsenic and Eh, sulfate, Fe, Mn, Mo and U. While the mobility of sulfate, uranium and molybdenum is possibly controlled by the change in redox conditions as the groundwater flows towards central parts of the basin, the reducing conditions alone cannot account for the occurrence of high arsenic groundwater in the basin but it does explain the characteristics of arsenic speciation. With one exception, all the groundwaters with As(III) as the major As species have low Eh and those with As(V) have high Eh. Reductive dissolution of Fe-oxyhydroxides or reduction of As(V) are consistent with the observations, however no increase in dissolved Fe concentration was noted. Furthermore, water from the well with the highest arsenic was relatively oxidizing and contained mostly As(V). From previous work Fe-oxyhydroxides are speculated to exist as coatings rather than primary minerals. The wide range of delta(34)S([SO4

  11. Incorporating Sulfur Inside the Pores of Carbons for Advanced Lithium-Sulfur Batteries: An Electrolysis Approach.

    PubMed

    He, Bin; Li, Wen-Cui; Yang, Chao; Wang, Si-Qiong; Lu, An-Hui

    2016-01-26

    We have developed an electrolysis approach that allows effective and uniform incorporation of sulfur inside the micropores of carbon nanosheets for advanced lithium-sulfur batteries. The sulfur-carbon hybrid can be prepared with a 70 wt % sulfur loading, in which no nonconductive sulfur agglomerations are formed. Because the incorporated sulfur is electrically connected to the carbon matrix in nature, the hybrid cathode shows excellent electrochemical performance, including a high reversible capacity, good rate capability, and good cycling stability, as compared to one prepared using the popular melt-diffusion method.

  12. High-Resolution Isotope Records of the Late Ordovician and Late Carboniferous: A Comparative Perspective on Glacial Carbon and Sulfur Cycles

    NASA Astrophysics Data System (ADS)

    Gill, B. C.; Lyons, T. W.; Saltzman, M. R.

    2005-12-01

    Carbonate-associated sulfate (CAS) faithfully tracks the sulfur isotope composition of seawater in both modern and ancient environments. Therefore, analyses of carbonate rocks permit the generation of parallel, high-resolution carbon and sulfur isotope data for seawater spanning geologic history. Our previous work in the early and middle Paleozoic has revealed parallel, short-term (1-4 Myrs) carbon and sulfur isotope excursions. The relationship between the two isotope systems seems to change over time, perhaps tracking longer-term evolution of the marine sulfur reservoir and of the primary loci of carbon burial, including increased burial on land. CAS isotope records therefore have the potential to shed essential mechanistic light on the causes (global versus regional) for carbon isotope excursions observed throughout the geological record. Previous work on the Late Carboniferous and Late Ordovician documented the existence of carbon isotope excursions of varying magnitude during these glacial episodes. The Late Carboniferous glaciations classically show evidence for multiple glacial-interglacial cycles with repeated, low magnitude (1 to 3 per mil) carbon isotope excursions. By contrast, the Late Ordovician was characterized by a short-lived glaciation with a corresponding single 4-6 per mil carbon isotope excursion. The modes and rates of carbon cycling reflected in the differing styles of C isotope behavior are the subject of debate, making these time-slices ideal for the CAS isotope approach. Carbon and sulfur isotope data from Pennsylvanian (Missourian Stage) cyclothems exposed in Kansas City, Missouri, show rapid isotope variability. We have preliminarily attributed these rapid changes to local reservoir effects linked to fluctuating sea level and its relationship to black shale deposition within the midcontinent basin and weathering on the basin margin during lowstands. Other work on the cyclic Carboniferous Bird Spring Formation, Nevada, is also

  13. Wet Chemistry Synthesis of Multidimensional Nanocarbon-Sulfur Hybrid Materials with Ultrahigh Sulfur Loading for Lithium-Sulfur Batteries.

    PubMed

    Du, Wen-Cheng; Yin, Ya-Xia; Zeng, Xian-Xiang; Shi, Ji-Lei; Zhang, Shuai-Feng; Wan, Li-Jun; Guo, Yu-Guo

    2016-02-17

    An optimized nanocarbon-sulfur cathode material with ultrahigh sulfur loading of up to 90 wt % is realized in the form of sulfur nanolayer-coated three-dimensional (3D) conducting network. This 3D nanocarbon-sulfur network combines three different nanocarbons, as follows: zero-dimensional carbon nanoparticle, one-dimensional carbon nanotube, and two-dimensional graphene. This 3D nanocarbon-sulfur network is synthesized by using a method based on soluble chemistry of elemental sulfur and three types of nanocarbons in well-chosen solvents. The resultant sulfur-carbon material shows a high specific capacity of 1115 mA h g(-1) at 0.02C and good rate performance of 551 mA h g(-1) at 1C based on the mass of sulfur-carbon composite. Good battery performance can be attributed to the homogeneous compositing of sulfur with the 3D hierarchical hybrid nanocarbon networks at nanometer scale, which provides efficient multidimensional transport pathways for electrons and ions. Wet chemical method developed here provides an easy and cost-effective way to prepare sulfur-carbon cathode materials with high sulfur loading for application in high-energy Li-S batteries.

  14. Demonstration of sulfur solubility determinations in high waste loading, low-activity waste glasses

    SciTech Connect

    Fox, K. M.

    2016-04-25

    A method recommended by Pacific Northwest National Laboratory (PNNL) for sulfate solubility determinations in simulated low-activity waste glasses was demonstrated using three compositions from a recent Hanford high waste loading glass study. Sodium and sulfate concentrations in the glasses increased after each re-melting step. Visual observations of the glasses during the re-melting process reflected the changes in composition. The measured compositions showed that the glasses met the targeted values. The amount of SO3 retained in the glasses after washing was relatively high, ranging from 1.6 to 2.6 weight percent (wt %). Measured SnO2 concentrations were notably low in all of the study glasses. The composition of the wash solutions should be measured in future work to determine whether SnO2 is present with the excess sulfate washed from the glass. Increases in batch size and the amount of sodium sulfate added did not have a measureable impact on the amount of sulfate retained in the glass, although this was tested for only a single glass composition. A batch size of 250 g and a sodium sulfate addition targeting 7 wt %, as recommended by PNNL, will be used in future experiments.

  15. The importance of sulfur for the behavior of highly-siderophile elements during Earth's differentiation

    NASA Astrophysics Data System (ADS)

    Laurenz, Vera; Rubie, David C.; Frost, Daniel J.; Vogel, Antje K.

    2016-12-01

    The highly siderophile elements (HSEs) are widely used as geochemical tracers for Earth's accretion and core formation history. It is generally considered that core formation strongly depleted the Earth's mantle in HSEs, which were subsequently replenished by a chondritic late veneer. However, open questions remain regarding the origin of suprachondritic Ru/Ir and Pd/Ir ratios that are thought to be characteristic for the primitive upper mantle. In most core-formation models that address the behavior of the HSEs, light elements such as S entering the core have not been taken into account and high P-T experimental data for S-bearing compositions are scarce. Here we present a comprehensive experimental study to investigate the effect of increasing S concentration in the metal on HSE metal-silicate partitioning at 2473 K and 11 GPa. We show that the HSEs become less siderophile with increasing S concentrations in the metal, rendering core-forming metal less efficient in removing the HSEs from the mantle if S is present. Furthermore, we investigated the FeS sulfide-silicate partitioning of the HSEs as a function of pressure (7-21 GPa) and temperature (2373-2673 K). The sulfide-silicate partition coefficient for Pt increases strongly with P, whereas those for Pd, Ru and Ir all decrease. The combined effect is such that above ∼20 GPa Ru becomes less chalcophile than Pt, which is opposite to their behavior in the metal-silicate system where Ru is always more siderophile than Pt. The newly determined experimental results are used in a simple 2-stage core formation model that takes into account the effect of S on the behavior of the HSEs during core formation. Results of this model show that segregation of a sulfide liquid to the core from a mantle with substantial HSE concentrations plays a key role in reproducing Earth's mantle HSE abundances. As Ru and Pd are less chalcophile than Pt and Ir at high P-T, some Ru and Pd remain in the mantle after sulfide segregation

  16. Process for measuring degradation of sulfur hexafluoride in high voltage systems

    DOEpatents

    Sauers, Isidor

    1986-01-01

    This invention is a method of detecting the presence of toxic and corrosive by-products in high voltage systems produced by electrically induced degradation of SF.sub.6 insulating gas in the presence of certain impurities. It is an improvement over previous methods because it is extremely sensitive, detecting by-products present in parts per billion concentrations, and because the device employed is of a simple design and takes advantage of the by-products natural affinity for fluoride ions. The method employs an ion-molecule reaction cell in which negative ions of the by-products are produced by fluorine attachment. These ions are admitted to a negative ion mass spectrometer and identified by their spectra. This spectrometry technique is an improvement over conventional techniques because the negative ion peaks are strong and not obscured by a major ion spectra of the SF.sub.6 component as is the case in positive ion mass spectrometry.

  17. Aubrite basalt vitrophyres: The missing basaltic component and high-sulfur silicate melts

    NASA Astrophysics Data System (ADS)

    Fogel, Robert A.

    2005-03-01

    Aubrite basalt vitrophyres (ABVs) are clastic inclusions found in enstatite chondrites and aubrites. Three have been discovered so far; PAI from the Parsa EH3 chondrite, KTI from the Khor Temiki aubrite and L87I from the LEW 87007 aubrite. Their significance stems from the fact that their parental melts were formed from source materials similar to E chondrites; therefore, they provide an opportunity to study the process of aubrite formation from an E chondrite-like protolith. KTI, PAI and L87I contain the FeO-poor highly reduced assemblage: forsterite + enstatite + silicate glass + kamacite + troilite. Additionally, KTI and PAI contain alabandite while L87I contains diopside. ABV glass contents are: 51 vol% for KTI; 30 vol% for PAI and 13 vol% for L87I. The ABVs are, thus, representative of the different stages of crystallization of a reduced precursor basalt similar to that which gave rise to the aubrites. The chemistry of all three ABVs can be projected onto the system forsterite-albite-silica. This system is where the bulk compositions of E chondrites fall. The melting relations in this system outline the melting of aubrite parental liquids. ABV bulk compositions lie along the enstatite-forsterite reaction boundary and are generally distinct from E chondrite bulk compositions. Analysis of the forsterite-albite-silica system, and the loci of ABV bulk compositions relative to that of the enstatite chondrites shows that the ABVs can be derived by partial melting of an E chondrite protolith. The L87I vitrophyre is more oxidizing than KTI and PAI. This was determined by its: higher enstatite and forsterite FeO content, lack of alabandite, low kamacite Si content and low Ti in troilite. Forsterites enclosed in enstatite display a solid trend of anticorrelated MnO and FeO; contrary to the positive correlation found for olivines in most gecochemical settings. This anticorrelation can be explained by an oxidizing or reducing event that occurred to the L87I parental melt

  18. Process for measuring degradation of sulfur hexafluoride in high voltage systems

    DOEpatents

    Sauers, I.

    1985-04-23

    This invention is a method of detecting the presence of toxic and corrosive by-products in high voltage systems produced by electrically induced degradation of SF/sub 6/ insulating gas in the presence of certain impurities. It is an improvement over previous methods because it is extremely sensitive, detecting by-products present in parts per billion concentrations, and because the device employed is of a simple design and takes advantage of the by-products natural affinity for fluoride ions. The method employs an ion-molecule reaction cell in which negative ions of the by-products are produced by fluorine attachment. These ions are admitted to a negative ion mass spectrometer and identified by their spectra. This spectrometry technique is an improvement over conventional techniques because the negative ion peaks are strong and not obscured by a major ion spectra of the SF/sub 6/ component as is the case in positive ion mass spectrometry.

  19. High concentrations of manganese and sulfur in deposits on Murray Ridge, Endeavour Crater, Mars

    USGS Publications Warehouse

    Arvidson, Raymond E.; Squyres, Steven W.; Morris, Richard V.; Knoll, Andrew H.; Gellert, Ralf; Clark, Benton C.; Catalano, Jeffrey G.; Jolliff, Bradley L.; McLennan, Scott M.; Herkenhoff, Kenneth E.; VanBommel, Scott; Mittelfehldt, David W.; Grotzinger, John P.; Guinness, Edward A.; Johnson, Jeffrey R.; Bell, James F.; Farrand, William H.; Stein, Nathan; Fox, Valerie K.; Golombek, Matthew P.; Hinkle, Margaret A. G.; Calvin, Wendy M.; de Souza, Paulo A.

    2016-01-01

    Mars Reconnaissance Orbiter HiRISE images and Opportunity rover observations of the ~22 km wide Noachian age Endeavour Crater on Mars show that the rim and surrounding terrains were densely fractured during the impact crater-forming event. Fractures have also propagated upward into the overlying Burns formation sandstones. Opportunity’s observations show that the western crater rim segment, called Murray Ridge, is composed of impact breccias with basaltic compositions, as well as occasional fracture-filling calcium sulfate veins. Cook Haven, a gentle depression on Murray Ridge, and the site where Opportunity spent its sixth winter, exposes highly fractured, recessive outcrops that have relatively high concentrations of S and Cl, consistent with modest aqueous alteration. Opportunity’s rover wheels serendipitously excavated and overturned several small rocks from a Cook Haven fracture zone. Extensive measurement campaigns were conducted on two of them: Pinnacle Island and Stuart Island. These rocks have the highest concentrations of Mn and S measured to date by Opportunity and occur as a relatively bright sulfate-rich coating on basaltic rock, capped by a thin deposit of one or more dark Mn oxide phases intermixed with sulfate minerals. We infer from these unique Pinnacle Island and Stuart Island rock measurements that subsurface precipitation of sulfate-dominated coatings was followed by an interval of partial dissolution and reaction with one or more strong oxidants (e.g., O2) to produce the Mn oxide mineral(s) intermixed with sulfate-rich salt coatings. In contrast to arid regions on Earth, where Mn oxides are widely incorporated into coatings on surface rocks, our results demonstrate that on Mars the most likely place to deposit and preserve Mn oxides was in fracture zones where migrating fluids intersected surface oxidants, forming precipitates shielded from subsequent physical erosion.

  20. Ionic liquid-based electrolyte with binary lithium salts for high performance lithium-sulfur batteries

    NASA Astrophysics Data System (ADS)

    Wu, Feng; Zhu, Qizhen; Chen, Renjie; Chen, Nan; Chen, Yan; Ye, Yusheng; Qian, Ji; Li, Li

    2015-11-01

    Rechargeable Li-S batteries have suffered several technical obstacles, such as rapid capacity fading and low coulombic efficiency. To overcome these problems, we design new electrolytes containing N-methoxyethyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)-imide (Pyr1,2O1TFSI) and tri(ethylene glycol)dimethyl ether (TEGDME) in mass ratio of 7:3. Moreover, Lithium difluoro(oxalate)borate (LiODFB) is introduced for the modification. Although the addition of LiODFB as additive lead to extremely high viscosity of electrolyte and inferior performance of the cells, the electrolyte containing lithium bis(trifluoromethanesulfonyl)imide (LiTFSI, 0.84 nm) and LiODFB (0.60 nm) mixture with a total molar concentration of 0.4 mol kg-1 as binary lithium salt shows excellent electrochemical performance. The Pyr1,2O1TFSI/TEGDME electrolyte with LiTFSI/LiODFB binary lithium salts in mole ratio of 6:4 is obtained after optimizing ratio. The Li-S cells containing this electrolyte system show excellent capacity and cycle performance, whose initial discharge capacity is 1264.4 mAh g-1, and retains 911.4 mAh g-1 after 50 cycles with the coulombic efficiency more than 95%. It can be attributed the solid-electrolyte interphase (SEI)-forming ability of LiODFB which protect Li anode from suffering lithium dendrites and prevent the shuttle phenomenon. The novel electrolytes provide good cycling stability and high coulombic efficiency for the Li-S batteries, which is suggested as a promising electrolyte for Li-S batteries.

  1. Meteoritic Sulfur Isotopic Analysis

    NASA Technical Reports Server (NTRS)

    Thiemens, Mark H.

    1996-01-01

    Funds were requested to continue our program in meteoritic sulfur isotopic analysis. We have recently detected a potential nucleosynthetic sulfur isotopic anomaly. We will search for potential carriers. The documentation of bulk systematics and the possible relation to nebular chemistry and oxygen isotopes will be explored. Analytical techniques for delta(sup 33), delta(sup 34)S, delta(sup 36)S isotopic analysis were improved. Analysis of sub milligram samples is now possible. A possible relation between sulfur isotopes and oxygen was detected, with similar group systematics noted, particularly in the case of aubrites, ureilites and entstatite chondrites. A possible nucleosynthetic excess S-33 has been noted in bulk ureilites and an oldhamite separate from Norton County. High energy proton (approximately 1 GeV) bombardments of iron foils were done to experimentally determine S-33, S-36 spallogenic yields for quantitation of isotopic measurements in iron meteorites. Techniques for measurement of mineral separates were perfected and an analysis program initiated. The systematic behavior of bulk sulfur isotopes will continue to be explored.

  2. Iron–Sulfur Cluster Biogenesis Chaperones: Evidence for Emergence of Mutational Robustness of a Highly Specific Protein–Protein Interaction

    PubMed Central

    Delewski, Wojciech; Paterkiewicz, Bogumiła; Manicki, Mateusz; Schilke, Brenda; Tomiczek, Bartłomiej; Ciesielski, Szymon J.; Nierzwicki, Lukasz; Czub, Jacek; Dutkiewicz, Rafal; Craig, Elizabeth A.; Marszalek, Jaroslaw

    2016-01-01

    Biogenesis of iron–sulfur clusters (FeS) is a highly conserved process involving Hsp70 and J-protein chaperones. However, Hsp70 specialization differs among species. In most eukaryotes, including Schizosaccharomyces pombe, FeS biogenesis involves interaction between the J-protein Jac1 and the multifunctional Hsp70 Ssc1. But, in Saccharomyces cerevisiae and closely related species, Jac1 interacts with the specialized Hsp70 Ssq1, which emerged through duplication of SSC1. As little is known about how gene duplicates affect the robustness of their protein interaction partners, we analyzed the functional and evolutionary consequences of Ssq1 specialization on the ubiquitous J-protein cochaperone Jac1, by comparing S. cerevisiae and S. pombe. Although deletion of JAC1 is lethal in both species, alanine substitutions within the conserved His–Pro–Asp (HPD) motif, which is critical for Jac1:Hsp70 interaction, have species-specific effects. They are lethal in S. pombe, but not in S. cerevisiae. These in vivo differences correlated with in vitro biochemical measurements. Charged residues present in the J-domain of S. cerevisiae Jac1, but absent in S. pombe Jac1, are important for tolerance of S. cerevisiae Jac1 to HPD alterations. Moreover, Jac1 orthologs from species that encode Ssq1 have a higher sequence divergence. The simplest interpretation of our results is that Ssq1’s coevolution with Jac1 resulted in expansion of their binding interface, thus increasing the efficiency of their interaction. Such an expansion could in turn compensate for negative effects of HPD substitutions. Thus, our results support the idea that the robustness of Jac1 emerged as consequence of its highly efficient and specific interaction with Ssq1. PMID:26545917

  3. Demonstration of selective catalytic reduction (SCR) technology for the control of nitrogen oxide (NO sub x ) emissions from high-sulfur coal-fired boilers

    SciTech Connect

    Not Available

    1991-08-01

    The objective of this project is to demonstrate and evaluate commercially available Selective Catalytic Reduction (SCR) catalysts from US, Japanese and European catalyst suppliers on a high-sulfur US coal-fired boiler. SCR is a post-combustion nitrogen oxide (NOx) control technology that involves injecting ammonia into the flue gas generated from coal combustion in an electric utility boiler. The flue gas containing ammonia is then passed through a reactor that contains a specialized catalyst. In the presence of the catalyst, the ammonia reacts with NOx to convert it to nitrogen and water vapor, Although SCR is widely practiced in Japan and Europe, there are numerous technical uncertainties associated with applying SCR to US coals. These uncertainties include: (1) potential catalyst deactivation due to poisoning by trace metal species present in US coals that are not present in other fuel performance of the technology and effects on the balance-of-plant equipment in the presence of high amounts of SO{sub 2} and SO{sub 3}. (3) performance of a wide variety of SCR catalyst compositions, geometries and methods of manufacture under typical high-sulfur coal-fired utility operating conditions. These uncertainties will be explored by constructing a series of small-scale SCR reactors and simultaneously exposing different SCR catalysts to flue gas derived from the combustion of high sulfur US coal.

  4. Lithium Sulfur Primary Battery with Super High Energy Density: Based on the Cauliflower-like Structured C/S Cathode

    PubMed Central

    Ma, Yiwen; Zhang, Hongzhang; Wu, Baoshan; Wang, Meiri; Li, Xianfeng; Zhang, Huamin

    2015-01-01

    The lithium-sulfur primary batteries, as seldom reported in the previous literatures, were developed in this work. In order to maximize its practical energy density, a novel cauliflower-like hierarchical porous C/S cathode was designed, for facilitating the lithium-ions transport and sulfur accommodation. This kind of cathode could release about 1300 mAh g−1 (S) capacity at sulfur loading of 6 ~ 14 mg cm−2, and showed excellent shelf stability during a month test at room temperature. As a result, the assembled Li-S soft package battery achieved an energy density of 504 Wh kg−1 (654 Wh L−1), which was the highest value ever reported to the best of our knowledge. This work might arouse the interests on developing primary Li-S batteries, with great potential for practical application. PMID:26456914

  5. Lithium Sulfur Primary Battery with Super High Energy Density: Based on the Cauliflower-like Structured C/S Cathode

    NASA Astrophysics Data System (ADS)

    Ma, Yiwen; Zhang, Hongzhang; Wu, Baoshan; Wang, Meiri; Li, Xianfeng; Zhang, Huamin

    2015-10-01

    The lithium-sulfur primary batteries, as seldom reported in the previous literatures, were developed in this work. In order to maximize its practical energy density, a novel cauliflower-like hierarchical porous C/S cathode was designed, for facilitating the lithium-ions transport and sulfur accommodation. This kind of cathode could release about 1300 mAh g-1 (S) capacity at sulfur loading of 6 ~ 14 mg cm-2, and showed excellent shelf stability during a month test at room temperature. As a result, the assembled Li-S soft package battery achieved an energy density of 504 Wh kg-1 (654 Wh L-1), which was the highest value ever reported to the best of our knowledge. This work might arouse the interests on developing primary Li-S batteries, with great potential for practical application.

  6. Etching high aspect ratio structures in silicon using sulfur hexafluoride/oxygen plasma

    NASA Astrophysics Data System (ADS)

    Belen, Rodolfo Jun

    Plasma etching of high aspect ratio structures in Si is an important step in manufacturing capacitors for memory devices and integrated components of microelectromechanical systems. In these applications, the goal is to etch deep features anisotropically with high etch rates and selectivities to the mask while maintaining good uniformity and reproducibility. This study investigates the etching of deep sub-half-micron diameter holes in Si using SF6/O 2 plasma. Etching experiments and plasma diagnostics are combined with modeling to gain a fundamental understanding of the etching and passivation kinetics and mechanism necessary in developing and scaling-up processes. Etching experiments are conducted in an inductively coupled plasma reactor with a planar coil. The substrate electrode is biased with a separate rf power supply to achieve independent control of the ion flux and energy. The effects of pressure, rf-bias and SF6-to-O2 ratio in the feed gas on the etch rate, selectivity and feature profile shape are studied using Si wafers patterned with 0.35 mum-diameter holes in a SiO2 mask. Visualization of profiles using scanning electron microscopy is complemented by plasma diagnostics such as mass spectrometry and actinometry. Simultaneous with experiments, reactor-scale and feature-scale models are developed to quantify the etching and passivation kinetics and identify the important kinetic parameters that affect feature profile evolution. Information from plasma diagnostics and previously published data are used to reduce the degrees of freedom in the model. Experiments are designed to directly measure kinetic parameters such as the chemical etch rate constant and the incidence angle dependence of the etching yield. Experimentally inaccessible parameters such as the sticking coefficients, etching yield and ion scattering parameters are determined through feature profile simulation. The key internal plasma parameters that affect profile evolution are the F-to-O and F

  7. Co-firing high sulfur coal with refuse derived fuels. Technical report {number_sign}4

    SciTech Connect

    Pan, W.P.; Riley, J.T.; Lloyd, W.G.

    1995-08-03

    In order to study combustion performance under conditions similar to that in the AFBC system, the authors conducted a series of experiments at a heating rate of 100 C/min using the TGA/FTIR/MS system. Results indicate that more hydrocarbons are evolved at the faster heating rate, owing to incomplete combustion of the fuel. Chlorinated organic compounds can be formed at high heating rates. Certain oxidation products such as organic acids and alcohols are obtained at the slow heating rate. To simulate the conditions used in the atmospheric fluidized bed combustor (AFBC) at Western Kentucky University, studies were also conducted using a quartz tube in a tube furnace. The temperature conditions were kept identical to those of the combustor. The products evolved from the combustion of coal, PVC, and mixtures of the two were trapped in suitable solvents at different temperatures, and analyzed using the Shimadzu GC/MS system. The detection limits and the GC/MS analytical parameters were also established. The experiments were conducted keeping in mind the broader perspective; that of studying conditions conducive to the formation of chlorinated organic compounds from the combustion of coal/MSW blends. 32 figs., 16 tabs.

  8. Phase relations and sound velocity measurements of iron-sulfur systems at high pressure: implications for the Earth's inner core

    NASA Astrophysics Data System (ADS)

    Ohtani, E.; Kamada, S.; Sakai, T.; Terasaki, H.; Shibazaki, Y.; Sakamaki, T.; Takahashi, S.; Sakairi, T.; Fukui, H.; Baron, A. Q.

    2012-12-01

    The sound velocity is one of the most important physical properties which can be assessed by seismology. In spite of its importance, the technical difficulty provides limitation of the measurements under the core conditions. Here we show the results of measurements of the sound velocity of hcp-iron, Fe3S, and FeH by the inelastic X-ray scattering (IXS) method using DAC at high pressure and temperature. Inelastic X-ray scattering spectra were taken at BL35XU, Spring-8. We made the measurements of hcp-iron at pressures up to 180 GPa at room temperature, which is the highest pressure for the IXS measurement. Sound velocity measurements at high pressure and temperature were made up to 91 GPa at 700 K, and to 62 GPa and 1000 K using the external heating diamond anvil cell. The present results revealed that there is almost no temperature effect on the sound velocity of hcp-Fe at least up to 1000 K. We also measured the sound velocity and density of Fe3S up to 85 GPa at room temperature, and clarified the effect of sulfur and hydrogen on the sound velocity of iron at high pressure. Phase relations of the Fe-S (Kamada et al., 2010; 2012) and Fe-S-O systems (Terasaki et al., 2011) were studied up to the core pressures based on the laser heated diamond anvil cell combined with the in situ synchrotron X-ray diffraction at SPring-8. Fe3S dissolves first at the solidus before melting of FeO and metallic iron alloy at the liquidus of the systems up to 180 GPa. The maximum solubility of sulfur in hcp-iron approaches to about 7.5 at % at 86 GPa and 8 at % at 123 GPa, and it does not increase so much at higher pressures. The temperature at ICB based on the extrapolation of the liquidus and solidus temperatures of the outer core composition in the Fe-S-O is about 4360-5630 K assuming that the outer core composition is Fe75O5S20 in the atomic ratio. The temperature at the core-mantle boundary will be 3340-4300 K by the adiabatic decompression from the temperature at the inner core

  9. Uses of lunar sulfur

    NASA Technical Reports Server (NTRS)

    Vaniman, D.; Pettit, D.; Heiken, G.

    1992-01-01

    Sulfur and sulfur compounds have a wide range of applications for their fluid, electrical, chemical, and biochemical properties. Although known abundances on the Moon are limited (approximately 0.1 percent in mare soils), sulfur is relatively extractable by heating. Coproduction of sulfur during oxygen extraction from ilmenite-rich mare soils could yield sulfur in masses up to 10 percent of the mass of oxygen produced. Sulfur deserves serious consideration as a lunar resource.

  10. Uses of lunar sulfur

    SciTech Connect

    Vaniman, D.T.; Pettit, D.R.; Heiken, G.

    1988-01-01

    Sulfur and sulfur compounds have a wide range of applications for their fluid, electrical, chemical and biochemical properties. Although low in abundance on the Moon (/approximately/0.1% in mare soils), sulfur is surface-correlated and relatively extractable. Co-production of sulfur during oxygen extraction from ilmenite-rich soils could yield sulfur in masses up to 10% of the mass of oxygen produced. Sulfur deserves serious consideration as a lunar resource. 29 refs., 3 figs.

  11. Supraglacial sulfur springs and associated biological activity in the Canadian high arctic - signs of life beneath the ice

    USGS Publications Warehouse

    Grasby, Stephen E.; Allen, Carlton C.; Longazo, Teresa G.; Lisle, John T.; Griffin, Dale W.; Beauchamp, Benoit

    2003-01-01

    Unique springs, discharging from the surface of an arctic glacier, release H2S and deposit native sulfur, gypsum, and calcite. The presence of sulfur in three oxidation states indicates a complex series of redox reactions. Physical and chemical conditions of the spring water and surrounding environment, as well as mineralogical and isotopic signatures, suggest biologically mediated reactions. Cell counts and DNA analyses confirm bacteria are present in the spring system, and a limited number of sequenced isolates suggests that complex communities of bacteria live within the glacial system.

  12. Processes for preparing carbon fibers using sulfur trioxide in a halogenated solvent

    SciTech Connect

    Patton, Jasson T.; Barton, Bryan E.; Bernius, Mark T.; Chen, Xiaoyun; Hukkanen, Eric J.; Rhoton, Christina A.; Lysenko, Zenon

    2015-12-29

    Disclosed here are processes for preparing carbonized polymers (preferably carbon fibers), comprising sulfonating a polymer with a sulfonating agent that comprises SO.sub.3 dissolved in a solvent to form a sulfonated polymer; treating the sulfonated polymer with a heated solvent, wherein the temperature of the solvent is at least 95.degree. C.; and carbonizing the resulting product by heating it to a temperature of 500-3000.degree. C. Carbon fibers made according to these methods are also disclosed herein.

  13. The role of a conserved tyrosine residue in high-potential iron sulfur proteins.

    PubMed Central

    Iwagami, S. G.; Creagh, A. L.; Haynes, C. A.; Borsari, M.; Felli, I. C.; Piccioli, M.; Eltis, L. D.

    1995-01-01

    Conserved tyrosine-12 of Ectothiorhodospira halophila high-potential iron sulphur protein (HiPIP) iso-I was substituted with phenylalanine (Y12F), histidine (Y12H), tryptophan (Y12W), isoleucine (Y12I), and alanine (Y12A). Variants Y12A and Y12I were expressed to reasonable levels in cells grown at lower temperatures, but decomposed during purification. Variants Y12F, Y12H, and Y12W were substantially destabilized with respect to the recombinant wild-type HiPIP (rcWT) as determined by differential scanning calorimetry over a pH range of 7.0-11.0. Characterization of the Y12F variant by NMR indicates that the principal structural differences between this variant and the rcWT HiPIP result from the loss of the two hydrogen bonds of the Tyr-12 hydroxyl group with Asn-14 O delta 1 and Lys-59 NH, respectively. The effect of the loss of the latter interaction is propagated through the Lys-59/Val-58 peptide bond, thereby perturbing Gly-46. The delta delta GDapp of Y12F of 2.3 kcal/mol with respect to rcWT HiPIP (25 degrees C, pH 7.0) is entirely consistent with the contribution of these two hydrogen bonds to the stability of the latter. CD measurements show that Tyr-12 influences several electronic transitions within the cluster. The midpoint reduction potentials of variants Y12F, Y12H, and Y12W were 17, 19, and 22 mV (20 mM MOPS, 0.2 M sodium chloride, pH 6.98, 25 degrees C), respectively, higher than that of rcWT HiPIP. The current results indicate that, although conserved Tyr-12 modulates the properties of the cluster, its principle function is to stabilize the HiPIP through hydrogen bonds involving its hydroxyl group and electrostatic interactions involving its aromatic ring. PMID:8580847

  14. High Pressure Melting of Iron with Nonmetals Sulfur, Carbon, Oxygen, and Hydrogen: Implications for Planetary Cores

    NASA Astrophysics Data System (ADS)

    Buono, Antonio Salvatore

    The earth's core consists of a solid metallic center surrounded by a liquid metallic outer layer. Understanding the compositions of the inner and outer cores allows us to better understand the dynamics of the earth's core, as well as the dynamics of the cores of other terrestrial planets and moons. The density and size of the earth's core indicate that it is approximately 90% metallic, predominantly iron, with about 10% light elements. Iron meteorites, believed to be the remnants of planetary cores, provide further constraints on the composition of the earth's core, indicating a composition of 86% iron, 4% nickel, and 10% light elements. Any potential candidate for the major light element core component must meet two criteria: first, it must have high cosmic abundances and second, it must be compatible with Fe. Given these two constraints there are five plausible elements that could be the major light element in the core: H, O, C, S, and Si. Of these five possible candidates this thesis focuses on S and C as well exploring the effect of minor amounts of O and H on the eutectic temperature in a Fe-FeS core. We look at two specific aspects of the Fe-FeS system: first, the shape of the liquidus as a function of pressure, second, a possible cause for the reported variations in the eutectic temperature, which draws on the effect of H and O. Finally we look at the effect of S and C on partitioning behavior of Ni, Pt, Re,Co, Os and W between cohenite and metallic liquid. We are interested in constraining the shape of the Fe-FeS liquidus because as a planet with a S-enriched core cools, the thermal and compositional evolution of its core is constrained by this liquidus. In Chapter 1 I present an equation that allows for calculation of the temperature along the liquidus as a function of pressure and composition for Fe-rich compositions and pressures from 1 bar to 10 GPa. One particularly interesting feature of the Fe --rich side of the Fe-FeS eutectic is the sigmoidal shape

  15. Eddy covariance flux of sulfur dioxide to the sea surface: Air-side resistance to deposition of a highly soluble gas

    NASA Astrophysics Data System (ADS)

    Porter, J.; De Bruyn, W. J.; Miller, S. D.; Saltzman, E. S.

    2014-12-01

    Deposition to the sea surface represents a major atmospheric removal mechanism for sulfur dioxide and many other highly soluble products of tropospheric photochemistry. Such gases include nitric acid, ammonia, organic acids, sulfur dioxide, and highly soluble organic compounds such as methanol and acetone. The deposition of highly soluble gases is controlled by turbulent and diffusive transport on the air side of the air/sea interface. In this study, air/sea fluxes of the soluble gas sulfur dioxide (SO2 ), sensible and latent heat, and momentum were measured using eddy covariance. This was a pilot study carried out in April 2014 on Scripps pier in La Jolla, California, that was designed to assess the potential for measuring SO2 fluxes over the ocean. SO2 was detected using chemical ion mass spectrometry in negative ion mode with a sensitivity of roughly 100 Hz/ppt. The ionization scheme involved addition of ozone to a dried air stream and subsequent conversion of SO2 to the SO5 - ion. The results demonstrate the feasibility of seagoing SO2 flux measurements. Such measurements can be used to constrain the depositional velocities of soluble gases and test models for air-side resistance to air/sea gas transfer.

  16. In Situ Polymerized PAN-Assisted S/C Nanosphere with Enhanced High-Power Performance as Cathode for Lithium/Sulfur Batteries.

    PubMed

    Hu, Hao; Cheng, Haoyan; Liu, Zhengfei; Li, Guojian; Zhu, Qianchen; Yu, Ying

    2015-08-12

    Carbonaceous and polymer materials are extensively employed as conductor and container to encapsulate sulfur particles and limit polysulfide dissolution. Even so, high-power performance is still far from satisfaction due to the expansion and collapse of the electrode materials during thousands of charge-discharge process. Herein, it is found that colloidal carbon sphere with high elastic coefficient can be utilized as a framework to load sulfur, which can trap soluble polysulfides species in the pores within the sphere and efficaciously improve the electronic conductivity of the cathode. After modified by polyaniline (PAN) through in situ polymerization, PAN-assisted S/C nanosphere (PSCs-73, with 73 wt % sulfur) effectively minimize polysulfide diffusion, enhance the electron transfer rate and overcome the problem of volume expansion. The fabricated PSCs-73 cell shows outstanding long high-power cycling capability over 2500 charge/discharge cycles with a capacity decay of 0.01% per cycle at 5 C. Substantially, this composite can drive 2.28 W white indicators of LED robustly after minutes of charging by three lithium batteries in series, showing a promising potential application in the future.

  17. SULFUR POLYMER ENCAPSULATION.

    SciTech Connect

    KALB, P.

    2001-08-22

    recommended for treatment of wastes containing high concentrations of nitrates because of potentially dangerous reactions between sulfur, nitrate, and trace quantities of organics. Recently, the process has been adapted for the treatment of liquid elemental mercury and mercury contaminated soil and debris.

  18. Efficient Synthesis of Graphene Nanoscrolls for Fabricating Sulfur-Loaded Cathode and Flexible Hybrid Interlayer toward High-Performance Li-S Batteries.

    PubMed

    Guo, Yi; Zhao, Gang; Wu, Naiteng; Zhang, Yun; Xiang, Mingwu; Wang, Bo; Liu, Heng; Wu, Hao

    2016-12-21

    A modified lyophilization approach is developed and used for highly efficient transformation of 2D graphene oxide sheet into 1D graphene nanoscroll (GNS) with high topological transforming efficiency (∼94%). Because of the unique open tubular structure and large specific surface area (545 m(2) g(-1)), GNS is utilized for the first time as a porous cathode scaffold for encapsulating sulfur with a high loading (81 wt %), and also as a conductive skeleton for assembling MnO2 nanowires into a flexible free-standing hybrid interlayer, both enabling high-rate and long-life Li-S battery.

  19. Flue gas desulfurization of high sulfur coals retrofit costs, lime consumption and removal efficiencies 10 Mwe DOE demonstrate plant

    SciTech Connect

    Goss, W.L.

    1993-12-31

    AirPol, with the assistance of the Tennessee Valley Authority (TVA), is demonstrating the Gas Suspension Absorption (GSA) technology in the Clean Coal Technology project entitled {open_quote}10 MW Demonstration of Gas Suspension Absorption.{close_quote} AirPol is performing this demonstration under a Cooperative Agreement awarded by the United States Department of Energy (DOE) in October 1990, in Round III of the Clean Coal Technology Program. This project will be the first North American demonstration of the GSA system in its application for flue gas desulfurization. This low-cost retrofit project seeks to demonstrate the GSA system which is expected to remove more than 90% of the sulfur dioxide (SO{sub 2}) from coal-fired flue gas, while achieving a high utilization of reagent lime. TVA has provided its National Center for Emissions Research (NCER) as the host site and will provide operation and testing services during the operations and testing phase. The TVA NCER is located at the TVA Shawnee Fossil Plant in West Paducah, Kentucky. This Clean Coal Technology project is designed to demonstrate the GSA system`s performance in a coal-fired boiler application, and its suitability for retrofit at existing boiler plants. Air foxics testing and operation and testing of a 1 Mwe fabric filter were added to the operation/testing phase of the project. The additional testing work will be conducted for the purpose of determining the GSA`s performance in removal of air toxics and the significance of replacing the electrostatic precipitator with a fabric filter. The experience gained by AirPol in designing, manufacturing, and constructing the GSA equipment through executing this project will be used for future commercialization of the GSA system. Results of the operation and testing phase will be used to further improve the GSA system design and operation.

  20. Catalytic direct liquefaction of high-sulfur coals and their blends with asphaltite in the absence of a solvent

    SciTech Connect

    Omer Gul; Parvana Gafarova; Arif Hesenov; Harold H. Schobert; Oktay Erbatur

    2007-08-15

    Two high-sulfur Turkish coals (Mengen and Kangal) and an asphaltite (Avgamasya) were liquefied with and without the catalyst precursors ammonium heptamolybdate (AHM) and ammonium tetrathiomolybdate (ATTM) at 300, 350, 400, and 450{sup o}C. Blends of these coals with the asphaltite were also liquefied using ATTM. Effective conversions of both coals into oils and into asphaltene and preasphaltene fractions were achieved with both catalyst precursors, although ATTM was more effective than AHM. Maximum conversion for Mengen coal with ATTM (89.2%) was achieved at 400{sup o}C, although the maximum yield of oils (56.9%) was obtained at 450{sup o}C. Kangal, in the presence of ATTM, gave maximum conversion (87.7%) at 400{sup o}C; the corresponding oil yield (49.6%) was not much less than that obtained at 450{sup o}C (49.9%). Some retrogressive reactions toward the formation of aromatics were observed during liquefaction at 450{sup o}C in the presence of AHM or ATTM with both coals. Also, using these catalyst precursors results in effective hydrogenation of two-ring or higher condensed aromatics and effective hydrogenolysis of the alicyclic part of hydroaromatic structures. On the other hand, these catalyst precursors do not provide effective saturation of monoaromatic rings, although the use of ATTM yielded partial reduction of these compounds. The distribution of main product fractions obtained from these reactions and the detailed analysis of oils obtained are reported. 118 refs., 4 figs., 15 tabs.

  1. Sulfuric acid-sulfur heat storage cycle

    DOEpatents

    Norman, John H.

    1983-12-20

    A method of storing heat is provided utilizing a chemical cycle which interconverts sulfuric acid and sulfur. The method can be used to levelize the energy obtained from intermittent heat sources, such as solar collectors. Dilute sulfuric acid is concentrated by evaporation of water, and the concentrated sulfuric acid is boiled and decomposed using intense heat from the heat source, forming sulfur dioxide and oxygen. The sulfur dioxide is reacted with water in a disproportionation reaction yielding dilute sulfuric acid, which is recycled, and elemental sulfur. The sulfur has substantial potential chemical energy and represents the storage of a significant portion of the energy obtained from the heat source. The sulfur is burned whenever required to release the stored energy. A particularly advantageous use of the heat storage method is in conjunction with a solar-powered facility which uses the Bunsen reaction in a water-splitting process. The energy storage method is used to levelize the availability of solar energy while some of the sulfur dioxide produced in the heat storage reactions is converted to sulfuric acid in the Bunsen reaction.

  2. Low-temperature formation and stabilization of rare allotropes of cyclooctasulfur (β-S8 and γ-S8) in the presence of organic carbon at a sulfur-rich glacial site in the Canadian High Arctic

    NASA Astrophysics Data System (ADS)

    Lau, Graham E.; Cosmidis, Julie; Grasby, Stephen E.; Trivedi, Christopher B.; Spear, John R.; Templeton, Alexis S.

    2017-03-01

    Large-scale deposits of elemental sulfur form annually on a glacier's surface at Borup Fiord Pass in the Canadian High Arctic. However, the mechanisms of mineralization and stabilization of elemental sulfur at this site are currently unknown. Here we show that X-ray diffraction (XRD) data for fresh sulfur precipitates collected from the surface of a melt pool over sulfide-rich ice reveal the presence of three sulfur allotropes, α-S8, β-S8, and γ-S8 (the three solid forms of cyclooctasulfur (S8)). The detection of the β-S8 allotrope of elemental sulfur is notable, since β-S8 typically only forms in high temperature environments (>96 °C). The γ-S8 allotrope is also rare in natural settings and has previously been implicated as a signature of microbial sulfur cycling. Using combustion and infrared spectroscopy approaches, organic carbon is also detected within the sample bearing the three allotropes of elemental sulfur. Electron microscopy and scanning transmission X-ray microscopy (STXM) at the C K-edge show that the sulfur precipitates are intimately associated with the organic carbon at the submicron scale. The occurrence of β-S8 and γ-S8 in this low-temperature setting indicates that there are unknown pathways for the formation and stabilization of these rare allotropes of elemental sulfur. In particular, we infer that the occurrence of these allotropes is related to their association with organic carbon. The formation of carbon-associated sulfur globules may not be a direct by-product of microbial activity; however, a potential role of direct or indirect microbial mediation in the formation and stabilization of β-S8 and γ-S8 remains to be assessed.

  3. Chemical bonding in the outer core: high-pressure electronic structures of oxygen and sulfur in metallic iron

    USGS Publications Warehouse

    Sherman, David M.

    1991-01-01

    The electronic structures of oxygen and sulfur impurities in metallic iron are investigated to determine if pressure, temperature, and composition-induced changes in bonding might affect phase equilibria along the Fe-FeS and Fe-FeO binaries. -from Authors

  4. High sulfur content in dried distillers grains with solubles (DDGS) protects against oxidized lipids in DDGS by increasing sulfur-containing antioxidants in nursery pigs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Some sources of DDGS contain relatively high amounts of oxidized lipids produced from PUFA peroxidation during production process, but it is unclear whether these oxidized lipids negatively affect growth performance and metabolic oxidation status in pigs. The objective of this study was to compare t...

  5. High sulfur content in corn dried distillers grains with solubles protects against oxidized lipids by increasing sulfur-containing antioxidants in nursery pigs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Some sources of corn dried distillers grains with solubles (DDGS) contain relatively high amounts of oxidized lipids produced from PUFA peroxidation during the production process. These oxidized lipids may negatively affect growth performance and metabolic oxidation status of pigs. The objective of ...

  6. Sulfur Concentration of Martian Magmas at Sulfide Saturation at High Pressures and Temperatures - Implications for Martian Magma Ocean and Magmatic Differentiation

    NASA Astrophysics Data System (ADS)

    Ding, S.; Dasgupta, R.

    2012-12-01

    Sulfur is critical for a wide range of processes of terrestrial planets including thermal evolution of core and atmosphere and geochemistry of mantle and crust. For Mars, sulfur is particularly important because it may be abundant in the core [1] while SO 2 and H2 S might have exerted a strong greenhouse climate in the past [2]. A critical parameter that affects sulfur distribution during differentiation is the sulfur carrying capacity of mantle melts. However, most experiments constraining sulfur content at sulfide saturation (SCSS) are conducted on FeO poor (~5-12 wt.%) basalts [3] and recent experiments on high-FeO (~16-22 wt.%, [4]) Martian basalts are restricted to ≤0.8 GPa [5]. To constrain SCSS of Martian magmas at mantle conditions, we simulated basalt-sulfide melt equilibria (S added as 15-30 wt.% FeS) in Gr capsules using a piston cylinder at 1-3 GPa and 1500-1700 °C. Two starting compositions, equivalent to olivine-phyric shergottites Yamato980459 (Y98; ~17.53 wt.% FeO) and NWA 2990 (NWA; ~16.42 wt.% FeO) and thought to be primary magma [6] were used. A composition Y98+1.4 wt.% H2O was also explored to constrain the effect of water on SCSS. All experiments produced quenched sulfide and silicate melts ± opx . FeS species in the NWA glasses was confirmed from peaks at 300-400 cm-1 in Raman spectra [7]. At 1600 °C, SCSS, measured using EPMA, decreases with pressure, 4800 to 3500 ppm from 1 to 2.5 GPa for Y98, ~5440 to 4380 ppm from 1 to 2 GPa for Y98+1.4 wt.% H2O, and 5000 to 3000 ppm from 1 to 3 GPa for NWA. At 2 GPa, SCSS of NWA increases with temperature, 3300 to 4600 ppm from 1500 to 1700 °C. Combining new and previous experiments on Martian basalts [5] (a total of 28 SCSS data with FeO* of 9.3-32.78 wt.%), a preliminary equation of the form LnS (ppm) = a + b.P + c/T +d.XSiO2 + e.XAl2O3 + f.LnXFeO was fitted, where P is in GPa, T in K, and X represents mole fraction of a given oxide. Our study suggests that at conditions of final melt

  7. Histology of Irreversible pulpitis premolars treated with mineral trioxide aggregate pulpotomy.

    PubMed

    Chueh, Ling-Huey; Chiang, Chun-Pun

    2010-01-01

    Studies show that human permanent teeth with carious pulpal exposures can result in a high clinical success rate when treated with pulpotomy and direct pulp capping with mineral trioxide aggregate (MTA pulpotomy). In this case report, a 19-year-old female patient with a second premolar with irreversible pulpitis and symptomatic apical periodontitis was treated with MTA pulpotomy. Follow-up electric pulp tests showed viability of the tooth at three and 10 months. Ten months after the initial treatment, the tooth was extracted for orthodontic reasons and processed for histological examination. Microscopically, the pulpal wound treated with MTA was free from inflammation and covered with a thin layer of reparative dentin. The authors conclude that, when caries and bacterial contamination can be removed from the dentin-pulp complex, the inflamed but vital pulp of a permanent tooth may have a chance to return to a healthy, functional status after MTA pulpotomy.

  8. Synthesis of Bi{sub 2}S{sub 3} with different sulfur content by conventional high temperature solid state solvothermal route

    SciTech Connect

    Solanki, S. I. Patel, I. B.; Shah, N. M.

    2014-04-24

    Bismuth sulfide (Bi{sub 2}S{sub 3}) is a binary chalcogenide compound material belonging to V-VI group of semiconductors. Because of its direct band gap of 1.3 eV and high figure of merit (ZT) value, it is widely used as a thermo electronic-cooling material based on the Peltier effect. The electrical and optical property of Bi{sub 2}S{sub 3} material is strongly dependent on stoichiometric composition, defect chemistry and structure. In this study, we have synthesized Bi{sub 2}S{sub x} (x = 3.15, 3.30, 3.45) compound material with different sulfur content by conventional high temperature solid state solvothermal reaction of bismuth and sulfur. X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDXS) analysis of synthesized compound materials were carried out to observe crystallinity, surface morphology and composition of elements in the compound. The optical analysis revealed that energy band gap decreases with increase of sulfur content.

  9. Sulfuric acid and hydrogen peroxide surface passivation effects on AlGaN/GaN high electron mobility transistors

    SciTech Connect

    Zaidi, Z. H. Lee, K. B.; Qian, H.; Jiang, S.; Houston, P. A.; Guiney, I.; Wallis, D. J.; Humphreys, C. J.

    2014-12-28

    In this work, we have compared SiN{sub x} passivation, hydrogen peroxide, and sulfuric acid treatment on AlGaN/GaN HEMTs surface after full device fabrication on Si substrate. Both the chemical treatments resulted in the suppression of device pinch-off gate leakage current below 1 μA/mm, which is much lower than that for SiN{sub x} passivation. The greatest suppression over the range of devices is observed with the sulfuric acid treatment. The device on/off current ratio is improved (from 10{sup 4}–10{sup 5} to 10{sup 7}) and a reduction in the device sub-threshold (S.S.) slope (from ∼215 to 90 mV/decade) is achieved. The sulfuric acid is believed to work by oxidizing the surface which has a strong passivating effect on the gate leakage current. The interface trap charge density (D{sub it}) is reduced (from 4.86 to 0.90 × 10{sup 12 }cm{sup −2} eV{sup −1}), calculated from the change in the device S.S. The gate surface leakage current mechanism is explained by combined Mott hopping conduction and Poole Frenkel models for both untreated and sulfuric acid treated devices. Combining the sulfuric acid treatment underneath the gate with the SiN{sub x} passivation after full device fabrication results in the reduction of D{sub it} and improves the surface related current collapse.

  10. Fossilization of melanosomes via sulfurization.

    PubMed

    McNamara, Maria E; van Dongen, Bart E; Lockyer, Nick P; Bull, Ian D; Orr, Patrick J

    2016-05-01

    Fossil melanin granules (melanosomes) are an important resource for inferring the evolutionary history of colour and its functions in animals. The taphonomy of melanin and melanosomes, however, is incompletely understood. In particular, the chemical processes responsible for melanosome preservation have not been investigated. As a result, the origins of sulfur-bearing compounds in fossil melanosomes are difficult to resolve. This has implications for interpretations of original colour in fossils based on potential sulfur-rich phaeomelanosomes. Here we use pyrolysis gas chromatography mass spectrometry (Py-GCMS), fourier transform infrared spectroscopy (FTIR) and time of flight secondary ion mass spectrometry (ToF-SIMS) to assess the mode of preservation of fossil microstructures, confirmed as melanosomes based on the presence of melanin, preserved in frogs from the Late Miocene Libros biota (NE Spain). Our results reveal a high abundance of organosulfur compounds and non-sulfurized fatty acid methyl esters in both the fossil tissues and host sediment; chemical signatures in the fossil tissues are inconsistent with preservation of phaeomelanin. Our results reflect preservation via the diagenetic incorporation of sulfur, i.e. sulfurization (natural vulcanization), and other polymerization processes. Organosulfur compounds and/or elevated concentrations of sulfur have been reported from melanosomes preserved in various invertebrate and vertebrate fossils and depositional settings, suggesting that preservation through sulfurization is likely to be widespread. Future studies of sulfur-rich fossil melanosomes require that the geochemistry of the host sediment is tested for evidence of sulfurization in order to constrain interpretations of potential phaeomelanosomes and thus of original integumentary colour in fossils.

  11. Cytochromes and iron sulfur proteins in sulfur metabolism of phototrophic bacteria

    NASA Technical Reports Server (NTRS)

    Fischer, U.

    1985-01-01

    Dissimilatory sulfur metabolism in phototrophic sulfur bacteria provides the bacteria with electrons for photosynthetic electron transport chain and, with energy. Assimilatory sulfate reduction is necessary for the biosynthesis of sulfur-containing cell components. Sulfide, thiosulfate, and elemental sulfur are the sulfur compounds most commonly used by phototrophic bacteria as electron donors for anoxygenic photosynthesis. Cytochromes or other electron transfer proteins, like high-potential-iron-sulfur protein (HIPIP) function as electron acceptors or donors for most enzymatic steps during the oxidation pathways of sulfide or thiosulfate. Yet, heme- or siroheme-containing proteins themselves undergo enzymatic activities in sulfur metabolism. Sirohemes comprise a porphyrin-like prosthetic group of sulfate reductase. eenzymatic reactions involve electron transfer. Electron donors or acceptors are necessary for each reaction. Cytochromes and iron sulfur problems, are able to transfer electrons.

  12. Properties of Sulfur Concrete.

    DTIC Science & Technology

    1979-07-06

    This report summarizes the state of the art of sulfur concrete . Sulfur concrete is created by mixing molten sulfur with aggregate and allowing the...and many organic compounds. It works well as a rapid runway repair material. Sulfur concrete also has unfavorable properties. It has poor durability

  13. Picosecond pulse radiolysis of highly concentrated sulfuric acid solutions: evidence for the oxidation reactivity of radical cation H2O(•+).

    PubMed

    Ma, Jun; Schmidhammer, Uli; Mostafavi, Mehran

    2014-06-12

    Aqueous solution of sulfuric acid is used as a suitable system to investigate the reactivity of the short-lived radical cation H2O(•+) which is generated by radiation in water. Ten aqueous solutions containing sulfuric acid with concentration from 1 to 18 mol L(-1) are studied by picosecond pulse radiolysis. The absorbance of the secondary radical SO4(•-) (or HSO4(•)) formed within the 10 ps electron pulse is measured by a pulse-probe method in the visible range. The analysis of the kinetics show that the radicals of sulfuric acid are formed within the picosecond electron pulse via two parallel mechanisms: direct electron detachment by the electron pulse and oxidation by the radical cation of water H2O(•+). In highly concentrated solution when SO4(2-) is in contact with H2O(•+), the electron transfer becomes competitive against proton transfer with another water molecule. Therefore, H2O(•+) may act as an extremely strong oxidant. The maximum radiolytic yield of scavenged H2O(•+) is estimated to be 5.3 ± 0.1 × 10(-7) mol J(-1).

  14. Investigation of chemical modifiers for sulfur determination in diesel fuel samples by high-resolution continuum source graphite furnace molecular absorption spectrometry using direct analysis

    NASA Astrophysics Data System (ADS)

    Huber, Charles S.; Vale, Maria Goreti R.; Welz, Bernhard; Andrade, Jailson B.; Dessuy, Morgana B.

    2015-06-01

    High-resolution continuum source graphite furnace molecular absorption spectrometry has been applied for sulfur determination in diesel fuel. The sharp rotational lines of the carbon monosulfide molecule (formed during the vaporization step) were used to measure the absorbance. The analytical line at 258.056 nm was monitored using the sum of three pixels. Different chemical modifiers were investigated and the mixture of palladium and magnesium was used as chemical modifier in combination with iridium as permanent modifier. L-Cysteine was chosen as sulfur standard and the calibration was done against aqueous standard solutions. The proposed method was applied for the analyses of four diesel samples: two S10 samples and two S500 samples. The trueness of the method was checked with a certified reference material (CRM) of sulfur in diesel fuel (NIST 2724b). Accurate results, for samples and CRM, were achieved after a dilution with propan-1-ol. The following figures of merit were obtained: characteristic mass of 17 ± 3 ng, limit of detection and limit of quantification of 1.4 mg kg- 1 and 4.7 mg kg- 1, respectively.

  15. Characterization of Sulfur and Nanostructured Sulfur Battery Cathodes in Electron Microscopy Without Sublimation Artifacts.

    PubMed

    Levin, Barnaby D A; Zachman, Michael J; Werner, Jörg G; Sahore, Ritu; Nguyen, Kayla X; Han, Yimo; Xie, Baoquan; Ma, Lin; Archer, Lynden A; Giannelis, Emmanuel P; Wiesner, Ulrich; Kourkoutis, Lena F; Muller, David A

    2017-02-01

    Lithium sulfur (Li-S) batteries have the potential to provide higher energy storage density at lower cost than conventional lithium ion batteries. A key challenge for Li-S batteries is the loss of sulfur to the electrolyte during cycling. This loss can be mitigated by sequestering the sulfur in nanostructured carbon-sulfur composites. The nanoscale characterization of the sulfur distribution within these complex nanostructured electrodes is normally performed by electron microscopy, but sulfur sublimates and redistributes in the high-vacuum conditions of conventional electron microscopes. The resulting sublimation artifacts render characterization of sulfur in conventional electron microscopes problematic and unreliable. Here, we demonstrate two techniques, cryogenic transmission electron microscopy (cryo-TEM) and scanning electron microscopy in air (airSEM), that enable the reliable characterization of sulfur across multiple length scales by suppressing sulfur sublimation. We use cryo-TEM and airSEM to examine carbon-sulfur composites synthesized for use as Li-S battery cathodes, noting several cases where the commonly employed sulfur melt infusion method is highly inefficient at infiltrating sulfur into porous carbon hosts.

  16. Advanced Sulfur Control Processing

    SciTech Connect

    Gangwal, S.K.; Portzer, J.W.; Turk, B.S.; Gupta, R.

    1996-12-31

    The primary objective of this project is to determine the feasibility of an alternate concept for the regeneration of high temperature desulfurization sorbents in which elemental sulfur, instead of SO{sub 2}, is produced. If successful, this concept will eliminate or alleviate problems caused by the highly exothermic nature of the regeneration reaction, the tendency for metal sulfate formation, and the need to treat the regeneration off-gas to prevent atmospheric SO{sub 2}, emissions. Iron and cerium-based sorbents were chosen on the basis of thermodynamic analysis to determine the feasibility of elemental sulfur production. The ability of both to remove H{sub 2}S during the sulfidation phase is less than that of zinc-based sorbents, and a two-stage desulfurization process will likely be required. Preliminary experimental work used electrobalance reactors to compare the relative rates of reaction of O{sub 2} and H{sub 2}O with FeS. More detailed studies of the regeneration of FeS as well as the sulfidation of CeO{sub 2} and regeneration of Ce{sub 2}O{sub 2}S are being carried out in a laboratory-scale fixed-bed reactor equipped with a unique analytical system which permits semi-continuous analysis of the distribution of elemental sulfur, H{sub 2}S, and SO{sub 2} in the reaction product gas.

  17. Band gap engineering and optical properties of tungsten trioxide

    NASA Astrophysics Data System (ADS)

    Ping, Yuan; Li, Yan; Rocca, Dario; Gygi, Francois; Galli, Giulia

    2012-02-01

    Tungsten trioxide (WO3) is a good photoanode material for water oxidation but it is not an efficient absorber of sunlight because of its large band gap (2.6 eV). Recently, stable clathrates of WO3 with interstitial N2 molecules were synthesized [1], which are isostructural to monoclinic WO3 but have a substantially smaller bang gap, 1.8 eV. We have studied the structural, electronic, an vibrational properties of N2-WO3 clathrates using ab-initio calculations and analyzed the physical origin of their gap reduction. We also studied the effect of atomic dopants, in particular rare gases. Substantial band gap reduction has been observed, especially in the case of doping with Xe, due to both electronic and structural effects. Absorption spectra have been computed by solving the Bethe-Salpeter Equation [2] to gain a thourough insight into the optical properties of pure and doped tungsten trioxide. [1] Q. Mi, Y. Ping, Y. Li., B.S. Brunschwig, G. Galli, H B. Gray, N S. Lewis (preprint) [2]D. Rocca, D. Lu and G. Galli, J. Chem. Phys. 133, 164109 (2010)

  18. Metagenome and Metatranscriptome Revealed a Highly Active and Intensive Sulfur Cycle in an Oil-Immersed Hydrothermal Chimney in Guaymas Basin.

    PubMed

    He, Ying; Feng, Xiaoyuan; Fang, Jing; Zhang, Yu; Xiao, Xiang

    2015-01-01

    The hydrothermal vent system is a typical chemosynthetic ecosystem in which microorganisms play essential roles in the geobiochemical cycling. Although it has been well-recognized that the inorganic sulfur compounds are abundant and actively converted through chemosynthetic pathways, the sulfur budget in a hydrothermal vent is poorly characterized due to the complexity of microbial sulfur cycling resulting from the numerous parties involved in the processes. In this study, we performed an integrated metagenomic and metatranscriptomic analysis on a chimney sample from Guaymas Basin to achieve a comprehensive study of each sulfur metabolic pathway and its hosting microorganisms and constructed the microbial sulfur cycle that occurs in the site. Our results clearly illustrated the stratified sulfur oxidation and sulfate reduction at the chimney wall. Besides, sulfur metabolizing is closely interacting with carbon cycles, especially the hydrocarbon degradation process in Guaymas Basin. This work supports that the internal sulfur cycling is intensive and the net sulfur budget is low in the hydrothermal ecosystem.

  19. Extraction, separation, and analysis of high sulfur coal. Technical progress report No. 16, July 15, 1991--October 15, 1991

    SciTech Connect

    Olesik, S.V.

    1991-12-31

    Two processes were studied in the period. The first was a study of oxidative desulfurization processes. Earlier research indicated that the use of copper-promoted oxidation of the organic and inorganic sulfur species in coal showed considerable promise. Initial studies utilizing CuCl{sub 2} demonstrated that the desulfurization yields were much lower than previously quoted. However, the experiments suggested that the reactant pathway showed promise and further investigations were conducted varying the solvent and replacing the Cl{sup {minus}} anion with the OH{sup {minus}} species. Ultimate analyses of these reactions are reported in addition to the experimental conditions used. Reactions using Cu(OH){sub 2}, CuCl{sub 2}, and copper cyclohexane butyrate are investigated. The second process discussed was desulfurization using selective solvation. Supercritical ethanol was used to investigate the extent of organic sulfur removal from coal. (VC)

  20. Resveratrol enhances the suppressive effects of arsenic trioxide on primitive leukemic progenitors.

    PubMed

    Wu, Edward J; Goussetis, Dennis J; Beauchamp, Elspeth; Kosciuczuk, Ewa M; Altman, Jessica K; Eklund, Elizabeth A; Platanias, Leonidas C

    2014-04-01

    Efforts to enhance the antileukemic properties of arsenic trioxide are clinically relevant and may lead to the development of new therapeutic approaches for the management of certain hematological malignancies. We provide evidence that concomitant treatment of acute myeloid leukemia (AML) cells or chronic myeloid leukemia (CML) cells with resveratrol potentiates arsenic trioxide-dependent induction of apoptosis. Importantly, clonogenic assays in methylcellulose demonstrate potent suppressive effects of the combination of these agents on primitive leukemic progenitors derived from patients with AML or CML. Taken together, these findings suggest that combinations of arsenic trioxide with resveratrol may provide an approach for targeting of early leukemic precursors and, possibly, leukemia initiating stem cells.

  1. High arsenic concentrations and enriched sulfur and oxygen isotopes in a fractured-bedrock ground-water system

    USGS Publications Warehouse

    Lipfert, G.; Sidle, W.C.; Reeve, A.S.; Ayuso, R.A.; Boyce, A.J.

    2007-01-01

    Ground water with high arsenic concentrations (up to 26.6????mol L- 1) has sulfate enriched in 34S and 18O in the fractured-bedrock, ground-water system of the Kelly's Cove watershed, Northport, Maine, USA. The ranges of sulfur and oxygen isotope values in aqueous sulfate, ??34S[SO4] and ??18O[SO4], at the Kelly's Cove watershed are + 3.4 to + 4.9??? and - 2.0 to + 6.7???, respectively. These isotope values are strikingly similar to those of the Goose River, Maine watershed which has ??34S[SO4] and ??18O[SO4] ranges of + 3.7 to + 4.6 ??? and - 2.6 to + 7.5???, respectively. In both systems, high arsenic concentrations occur with high ??34S[SO4] and ??18O[SO4] values, yet redox conditions and underlying rock types are quite different. The isotope values of sulfide minerals, ??34S[min], from four bedrock cores vary over short distances and range from - 5.1 to + 7.5???. The ??34S[SO4] values are controlled by the ??34S[min] values with minor input of atmospheric SO4. The much narrower range in ??34S[SO4] values than ??34S[min] values is probably due to sufficient ground-water mixing at a scale greater than the ??34S[min] variability. The ??34S[SO4] values are about 2??? higher than the average ??34S[min] value and fall within the range of ??34S[min] values, indicating only minor fractionation due to bacterial reduction of SO4. The highest ??18O[SO4] values were measured in the downgradient, confined, arsenic-rich ground water. High ??18O[SO4] values there cannot be due to aeration by atmospheric oxygen, but may arise from reoxidation of reduced SO4 products. The enrichment factors of ??18O in SO4 compared to H2O, + 7.2 to + 15.5???, in the Kelly's Cove ground water and the negligible 34S enrichment is very similar to those derived from experimental data of anaerobic sulfide oxidation in the presence of Mn and Fe oxides. Sea level at the Kelly's Cove watershed was approximately 80??m above present sea level about 13 000??years before present, imposing reducing

  2. Sulfur metabolism in phototrophic sulfur bacteria.

    PubMed

    Frigaard, Niels-Ulrik; Dahl, Christiane

    2009-01-01

    Phototrophic sulfur bacteria are characterized by oxidizing various inorganic sulfur compounds for use as electron donors in carbon dioxide fixation during anoxygenic photosynthetic growth. These bacteria are divided into the purple sulfur bacteria (PSB) and the green sulfur bacteria (GSB). They utilize various combinations of sulfide, elemental sulfur, and thiosulfate and sometimes also ferrous iron and hydrogen as electron donors. This review focuses on the dissimilatory and assimilatory metabolism of inorganic sulfur compounds in these bacteria and also briefly discusses these metabolisms in other types of anoxygenic phototrophic bacteria. The biochemistry and genetics of sulfur compound oxidation in PSB and GSB are described in detail. A variety of enzymes catalyzing sulfur oxidation reactions have been isolated from GSB and PSB (especially Allochromatium vinosum, a representative of the Chromatiaceae), and many are well characterized also on a molecular genetic level. Complete genome sequence data are currently available for 10 strains of GSB and for one strain of PSB. We present here a genome-based survey of the distribution and phylogenies of genes involved in oxidation of sulfur compounds in these strains. It is evident from biochemical and genetic analyses that the dissimilatory sulfur metabolism of these organisms is very complex and incompletely understood. This metabolism is modular in the sense that individual steps in the metabolism may be performed by different enzymes in different organisms. Despite the distant evolutionary relationship between GSB and PSB, their photosynthetic nature and their dependency on oxidation of sulfur compounds resulted in similar ecological roles in the sulfur cycle as important anaerobic oxidizers of sulfur compounds.

  3. PVP-Assisted Synthesis of Uniform Carbon Coated Li2S/CB for High-Performance Lithium-Sulfur Batteries.

    PubMed

    Chen, Lin; Liu, Yuzi; Zhang, Fan; Liu, Caihong; Shaw, Leon L

    2015-11-25

    The lithium-sulfur (Li-S) battery is a great alternative to the state-of-the-art lithium ion batteries due to its high energy density. However, low utilization of active materials, the insulating nature of sulfur or lithium sulfide (Li2S), and polysulfide dissolution in organic liquid electrolyte lead to low initial capacity and fast performance degradation. Herein, we propose a facile and viable approach to address these issues. This new approach entails synthesis of Li2S/carbon black (Li2S/CB) cores encapsulated by a nitrogen-doped carbon shell with polyvinylpyrrolidone (PVP) assistance. Combining energy-filtered transmission electron microscopy (EFTEM) elemental mappings, XPS and FTIR measurements, it is confirmed that the as-synthesized material has a structure of a Li2S/CB core with a nitrogen-doped carbon shell (denoted as Li2S/CB@NC). The Li2S/CB@NC cathode yields an exceptionally high initial capacity of 1020 mAh/g based on Li2S mass at 0.1 C with stable Coulombic efficiency of 99.7% over 200 cycles. Also, cycling performance shows the capacity decay per cycle as small as 0.17%. Most importantly, to further understand the materials for battery applications, field emission transmission electron microscopy (FETEM) and elemental mapping tests without exposure to air for Li2S samples in cycled cells are reported. Along with the first ever FETEM and field emission scanning electron microscopy (FESEM) investigations of cycled batteries, Li2S/CB@NC cathode demonstrates the capability of robust core-shell nanostructures for different rates and improved capacity retention, revealing Li2S/CB@NC designed here as an outstanding system for high-performance lithium-sulfur batteries.

  4. Cardiac conduction block at multiple levels caused by arsenic trioxide therapy.

    PubMed

    Kathirgamanathan, Kala; Angaran, Paul; Lazo-Langner, Alejandro; Gula, Lorne J

    2013-01-01

    We present a rare case of a woman aged 62 years with refractory acute promyelocytic leukemia treated with arsenic trioxide leading to progressive, multilevel cardiac conduction block. After chelation treatment with dimercaprol, there was normalization of conduction.

  5. Antimony Trioxide (ATO) - Summary of External Peer Review and Public Comments and Disposition

    EPA Pesticide Factsheets

    This document summarizes the public and external peer review comments that the EPA’s Office of Pollution Prevention and Toxics (OPPT) received for the draft work plan risk assessment for Antimony Trioxide (ATO).

  6. Sulfur oxide adsorbents and emissions control

    DOEpatents

    Li, Liyu; King, David L.

    2006-12-26

    High capacity sulfur oxide absorbents utilizing manganese-based octahedral molecular sieve (Mn--OMS) materials are disclosed. An emissions reduction system for a combustion exhaust includes a scrubber 24 containing these high capacity sulfur oxide absorbents located upstream from a NOX filter 26 or particulate trap.

  7. Solubility of Sulfur Dioxide in Sulfuric Acid

    NASA Technical Reports Server (NTRS)

    Chang, K. K.; Compton, L. E.; Lawson, D. D.

    1982-01-01

    The solubility of sulfur dioxide in 50% (wt./wt.) sulfuric acid was evaluated by regular solution theory, and the results verified by experimental measurements in the temperature range of 25 C to 70 C at pressures of 60 to 200 PSIA. The percent (wt./wt.) of sulfur dioxide in 50% (wt./wt.) sulfuric acid is given by the equation %SO2 = 2.2350 + 0.0903P - 0.00026P 10 to the 2nd power with P in PSIA.

  8. Manganese and Ceria Sorbents for High Temperature Sulfur Removal from Biomass-Derived Syngas -- The Impact of Steam on Capacity and Sorption Mode

    SciTech Connect

    Cheah, S.; Parent, Y. O.; Jablonski, W. S.; Vinzant, T.; Olstad, J. L.

    2012-07-01

    Syngas derived from biomass and coal gasification for fuel synthesis or electricity generation contains sulfur species that are detrimental to downstream catalysts or turbine operation. Sulfur removal in high temperature, high steam conditions has been known to be challenging, but experimental reports on methods to tackle the problem are not often reported. We have developed sorbents that can remove hydrogen sulfide from syngas at high temperature (700 C), both in dry and high steam conditions. The syngas composition chosen for our experiments is derived from statistical analysis of the gasification products of wood under a large variety of conditions. The two sorbents, Cu-ceria and manganese-based, were tested in a variety of conditions. In syngas containing steam, the capacity of the sorbents is much lower, and the impact of the sorbent in lowering H{sub 2}S levels is only evident in low space velocities. Spectroscopic characterization and thermodynamic consideration of the experimental results suggest that in syngas containing 45% steam, the removal of H{sub 2}S is primarily via surface chemisorptions. For the Cu-ceria sorbent, analysis of the amount of H{sub 2}S retained by the sorbent in dry syngas suggests both copper and ceria play a role in H{sub 2}S removal. For the manganese-based sorbent, in dry conditions, there is a solid state transformation of the sorbent, primarily into the sulfide form.

  9. Defects and Transport in Lithium Niobium Trioxide

    NASA Astrophysics Data System (ADS)

    Mehta, Apurva

    1990-01-01

    This dissertation presents work done on characterizing the defects and transport properties of congruent LiNbO _3. The focus of the study is the high temperature (800^circC to 1000^circC) equilibrium defect structure. The majority defects are described in terms of the 'LiNbO_3-ilmenite' defect model previously presented (26). Here the emphasis is placed on quantifying the defect concentrations. Congruent LiNbO_3 is highly nonstoichiometric. The large concentration of ionic defects present are mobile and contribute to electrical conduction. The ionic conduction was separated from the total conduction using defect chemistry and the transference number thus obtained was checked against the transference number obtained in a galvanic cell measurement. LiNbO_3 is an insulator (band gap = 4 eV). Hence one assumes that almost all of the conduction electrons are created by reduction. The degree of oxygen nonstoichiometry, a measure of the extent of chemical reduction, and the electron concentrations, were quantified as a function of oxygen partial pressure and the temperature by coulometric titration. The nonstoichiometry thus obtained was compared with nonstoichiometry obtained by TGA measurements. By fixing the phase composition of the sample in a buffered system, a set of constant composition measurements could be undertaken. These constant composition measurements were used to obtain the enthalpy of formation of conduction electrons, 1.95 eV, and the hopping energy for their motion at elevated temperatures, 0.55 eV, independently. The sum of the two energies was obtained by measuring the temperature dependence of the electronic conduction. The sum of the energies was found to be in excellent agreement with the energy obtained from equilibrium conduction. In conclusion, a quantitative and self-consistent picture of defects and their migration in LiNbO _3 was obtained.

  10. Demonstration of selective catalytic reduction (SCR) technology for the control of nitrogen oxide (NOx) emissions from high-sulfur coal-fired boilers

    SciTech Connect

    Not Available

    1991-11-01

    The objective of this project is to demonstrate and evaluate commercially available Selective Catalytic Reduction (SCR) catalysts from US, Japanese and European catalyst suppliers on a high-sulfur US coal-fired boiler. SCR is a post-combustion nitrogen oxide (NO{sub x}) control technology that involves injecting ammonia into the flue gas generated from coal combustion in an electric utility boiler. The flue gas containing ammonia is then passed through a reactor that contains a specialized catalyst. In the presence of the catalyst, the ammonia reacts with NO{sub x} to convert it to nitrogen and water vapor.

  11. High-precision sulfur isotope composition of enstatite meteorites and implications of the formation and evolution of their parent bodies

    NASA Astrophysics Data System (ADS)

    Defouilloy, C.; Cartigny, P.; Assayag, N.; Moynier, F.; Barrat, J.-A.

    2016-01-01

    In order to better understand the formation and evolution of their parent bodies, the three isotope ratios of sulfur were analyzed in 33 enstatite meteorites (24 enstatite chondrites and 9 aubrites). The results show that on average all enstatite chondrite groups are enriched in the lightest isotopes compared to other chondrite groups, with means of δ34S of -0.28 ± 0.22‰ for EH3/4, -0.16 ± 0.16‰ for EH5, -0.32 ± 0.15‰ for EL3, -0.67 ± 0.16‰ for EL6 and -0.64 ± 0.00‰ for EL7 (all 1σ). Aubrites show a larger isotope variability in their composition, with a δ34S varying from -1.350‰ to +0.154‰. Contrary to previously published results, our data show a distinct composition for EL6 compared to other enstatite chondrites. This could be related to an impact-induced loss of isotopically heavy oldhamite (δ34S = by 3.62 ± 3.02‰ (1σ)) on the EL parent body. Although the bulk sulfur in both enstatite meteorites and aubrites does not show any significant Δ33S and Δ36S, the oldhamite fraction shows clear evidence of mass independent fractionation on the 36S/32S ratio (in 3 out of 9 analyzes, Δ36S up to +2.2‰), a signal that is not correlated to any 33S/32S anomaly (in 1 out of 9 analyzes, Δ33S down to -0.085‰). Though a nebular or photochemical origin cannot be ruled out, the most plausible mechanism to produce such isolated non-mass dependent 36S/32S anomalies would be a contribution of FeCl2 containing excesses of 36S due to the decay of 36Cl to the leached oldhamite fraction. Even though the sulfur isotopic composition measured in enstatite meteorites is distinct from the Bulk Silicate Earth (BSE), the isotopically lightest samples of EL6, EL7 and aubrites are approaching the isotopic composition of the BSE and enstatite meteorites remain the meteorites with the sulfur isotopic composition the closest to the terrestrial one.

  12. Mineral Trioxide Aggregate and Portland Cement for Direct Pulp Capping in Dog: A Histopathological Evaluation

    PubMed Central

    Bidar, Maryam; Naghavi, Neda; Mohtasham, Nooshin; Sheik-Nezami, Mahshid; Fallahrastegar, Amir; Afkhami, Farzaneh; Attaran Mashhadi, Negin; Nargesi, Iman

    2014-01-01

    Background and aims. Mineral trioxide aggregate and calcium hydroxide are considered the gold standard pulp-capping materials. Recently, Portland cement has been introduced with properties similar to those of mineral trioxide aggregate. Histopathological effects of direct pulp capping using mineral trioxide aggregate and Portland cements on dog dental pulp tissue were evaluated in the present study. Materials and methods. This histopatological study was carried out on 64 dog premolars. First, the pulp was exposed with a sterile bur. Then, the exposed pulp was capped with white or gray mineral trioxide aggregates and white or gray Portland cements in each quadrant and sealed with glass-ionomer. The specimens were evaluated under a light microscope after 6 months. Statistical analysis was carried out using Kruskal-Wallis test. Statistical significance was defined at α=5%. Results. There was no acute inflammation in any of the specimens. Chronic inflammation in white and gray mineral trioxide aggregates and white and gray Portland cements was reported to be 45.5%, 27.3%, 57.1% and 34.1%, respectively. Although the differences were not statistically significant, severe inflammation was observed mostly adjacent to white mineral trioxide aggregate. The largest extent of increased vascularization (45%) and the least increase in fibrous tissue were observed adjacent to white mineral trioxide aggregate, with no significant differences. In addition, the least calcified tissue formed adjacent to white mineral trioxide aggregate, although the difference was not significant. Conclusion. The materials used in this study were equally effective as pulp protection materials following direct pulp capping in dog teeth. PMID:25346831

  13. Dye leakage and modification of fast-setting mineral trioxide aggregate.

    PubMed

    Challenger, Hereward; Lane, Jason; Becker, Ryan; Nassiripour, Sepehr; Torabinejad, Mahmoud

    2015-02-01

    The objective of this investigation was to determine and decrease dye leakage of fast-setting mineral trioxide aggregate (FSMTA). Specimens using differing setting times or concentrations of calcium sulfate modified FSMTA were assessed for dye penetration. Based on the results, no statistical difference was found in the dye leakage of FSMTA compared with regular mineral trioxide aggregate (MTA). The addition of 10 percent calcium sulfate resulted in a statistical reduction in dye leakage compared to both unmodified FSMTA and regular MTA.

  14. Mineral trioxide aggregate and portland cement for direct pulp capping in dog: a histopathological evaluation.

    PubMed

    Bidar, Maryam; Naghavi, Neda; Mohtasham, Nooshin; Sheik-Nezami, Mahshid; Fallahrastegar, Amir; Afkhami, Farzaneh; Attaran Mashhadi, Negin; Nargesi, Iman

    2014-01-01

    Background and aims. Mineral trioxide aggregate and calcium hydroxide are considered the gold standard pulp-capping materials. Recently, Portland cement has been introduced with properties similar to those of mineral trioxide aggregate. Histopathological effects of direct pulp capping using mineral trioxide aggregate and Portland cements on dog dental pulp tissue were evaluated in the present study. Materials and methods. This histopatological study was carried out on 64 dog premolars. First, the pulp was exposed with a sterile bur. Then, the exposed pulp was capped with white or gray mineral trioxide aggregates and white or gray Portland cements in each quadrant and sealed with glass-ionomer. The specimens were evaluated under a light microscope after 6 months. Statistical analysis was carried out using Kruskal-Wallis test. Statistical significance was defined at α=5%. Results. There was no acute inflammation in any of the specimens. Chronic inflammation in white and gray mineral trioxide aggregates and white and gray Portland cements was reported to be 45.5%, 27.3%, 57.1% and 34.1%, respectively. Although the differences were not statistically significant, severe inflammation was observed mostly adjacent to white mineral trioxide aggregate. The largest extent of increased vascularization (45%) and the least increase in fibrous tissue were observed adjacent to white mineral trioxide aggregate, with no significant differences. In addition, the least calcified tissue formed adjacent to white mineral trioxide aggregate, although the difference was not significant. Conclusion. The materials used in this study were equally effective as pulp protection materials following direct pulp capping in dog teeth.

  15. Lunar Sulfur Capture System

    NASA Technical Reports Server (NTRS)

    Berggren, Mark; Zubrin, Robert; Bostwick-White, Emily

    2013-01-01

    The Lunar Sulfur Capture System (LSCS) protects in situ resource utilization (ISRU) hardware from corrosion, and reduces contaminant levels in water condensed for electrolysis. The LSCS uses a lunar soil sorbent to trap over 98 percent of sulfur gases and about two-thirds of halide gases evolved during hydrogen reduction of lunar soils. LSCS soil sorbent is based on lunar minerals containing iron and calcium compounds that trap sulfur and halide gas contaminants in a fixed-bed reactor held at temperatures between 250 and 400 C, allowing moisture produced during reduction to pass through in vapor phase. Small amounts of Earth-based polishing sorbents consisting of zinc oxide and sodium aluminate are used to reduce contaminant concentrations to one ppm or less. The preferred LSCS configuration employs lunar soil beneficiation to boost concentrations of reactive sorbent minerals. Lunar soils contain sulfur in concentrations of about 0.1 percent, and halogen compounds including chlorine and fluorine in concentrations of about 0.01 percent. These contaminants are released as gases such as H2S, COS, CS2,HCl, and HF during thermal ISRU processing with hydrogen or other reducing gases. Removal of contaminant gases is required during ISRU processing to prevent hardware corrosion, electrolyzer damage, and catalyst poisoning. The use of Earth-supplied, single-use consumables to entirely remove contaminants at the levels existing in lunar soils would make many ISRU processes unattractive due to the large mass of consumables relative to the mass of oxygen produced. The LSCS concept of using a primary sorbent prepared from lunar soil was identified as a method by which the majority of contaminants could be removed from process gas streams, thereby substantially reducing the required mass of Earth-supplied consumables. The LSCS takes advantage of minerals containing iron and calcium compounds that are present in lunar soil to trap sulfur and halide gases in a fixedbed reactor

  16. Chemical characteristics of mineral trioxide aggregate and its hydration reaction

    PubMed Central

    2012-01-01

    Mineral trioxide aggregate (MTA) was developed in early 1990s and has been successfully used for root perforation repair, root end filling, and one-visit apexification. MTA is composed mainly of tricalcium silicate and dicalcium silicate. When MTA is hydrated, calcium silicate hydrate (CSH) and calcium hydroxide is formed. Formed calcium hydroxide interacts with the phosphate ion in body fluid and form amorphous calcium phosphate (ACP) which finally transforms into calcium deficient hydroxyapatite (CDHA). These mineral precipitate were reported to form the MTA-dentin interfacial layer which enhances the sealing ability of MTA. Clinically, the use of zinc oxide euginol (ZOE) based materials may retard the setting of MTA. Also, the use of acids or contact with excessive blood should be avoided before complete set of MTA, because these conditions could adversely affect the hydration reaction of MTA. Further studies on the chemical nature of MTA hydration reaction are needed. PMID:23429542

  17. Clinical Applications of Mineral Trioxide Aggregate: Report of Four Cases

    PubMed Central

    Battepati, Prashant M

    2010-01-01

    The greatest threats to developing teeth are dental caries and traumatic injuries. The primary goal of all restorative treatment is to maintain pulp vitality so that normal root development or apexogenesis can occur. If pulpal exposure occurs, then a pulpotomy procedure aims to preserve pulp vitality to allow for normal root development. Historically, calcium hydroxide has been the material of choice for pulpotomy procedures. Recently, an alternative material called mineral trioxide aggregate (MTA) has demonstrated the ability to induce hard-tissue formation in pulpal tissue. This article describes the clinical and radiographic outcome of a series of cases involving the use of MTA in pulpotomy, apexogenesis and apexification procedures and root perforations repair. PMID:27625556

  18. Mineral trioxide aggregate (MTA)-like materials: an update review.

    PubMed

    Mohammadi, Zahed; Shalavi, Sousan; Soltani, Mohammad Karim

    2014-09-01

    Mineral trioxide aggregate (MTA) is a multi-application material used in endodontics. It is a mixture of a refined Portland cement and bismuth oxide and trace amounts of SiO₂, CaO, MgO, K₂SO₄, and Na₂SO₄. MTA powder is mixed with supplied sterile water in a 3:1 powder/liquid. Hydrated MTA has an initial pH of 10.2, which rises to 12.5 three hours after mixing. There are several materials derived from MTA such as Endo-CPM Sealer, Ortho MTA, MTA-Fillapex, DiaRoot BioAggregate, MTA Bio, light-cured MTA, tricalcium silicate, and iRoot SP. The purpose of this article is to review MTA-like materials.

  19. Are the clouds of Venus sulfuric acid.

    NASA Technical Reports Server (NTRS)

    Young, A. T.

    1973-01-01

    It is shown that strong aqueous sulfuric acid solutions have the right refractive index and freeze at Venusian cloud temperature, explain the dryness of the Venusian stratosphere, are consistent with some features of the Venusian IR spectrum, and do not absorb in highly reflecting areas of Venus. It is also indicated that such solutions should be produced by reactions between known atmospheric constituents and most sulfur-bearing rock at the Venusian surface temperature, and require only small amounts of sulfur consistent with its cosmic abundance and with the amounts of other volatile elements present in the atmosphere. It is believed therefore that the clouds of Venus consist of sulfuric acid solutions.

  20. The CIA Targeting Complex Is Highly Regulated and Provides Two Distinct Binding Sites for Client Iron-Sulfur Proteins.

    PubMed

    Odermatt, Diana C; Gari, Kerstin

    2017-02-07

    The cytoplasmic iron-sulfur assembly (CIA) targeting complex is required for the transfer of an iron-sulfur (Fe-S) cluster to cytoplasmic and nuclear proteins, but how it engages with client proteins is unknown. Here, we show that the complex members MIP18 and CIAO1 associate with the C terminus of MMS19. By doing so, they form a docking site for Fe-S proteins that is disrupted in the absence of either MMS19 or MIP18. The Fe-S helicase XPD seems to be the only exception, since it can interact with MMS19 independently of MIP18 and CIAO1. We further show that the direct interaction between MMS19 and MIP18 is required to protect MIP18 from proteasomal degradation. Taken together, these data suggest a remarkably regulated interaction between the CIA targeting complex and client proteins and raise the possibility that Fe-S cluster transfer is controlled, at least in part, by the stability of the CIA targeting complex itself.

  1. Calcium looping process for high purity hydrogen production integrated with capture of carbon dioxide, sulfur and halides

    DOEpatents

    Ramkumar, Shwetha; Fan, Liang-Shih

    2015-11-04

    A process for producing hydrogen comprising the steps of: (i) gasifying a fuel into a raw synthesis gas comprising CO, hydrogen, steam, sulfur and halide contaminants in the form of H.sub.2S, COS, and HX, wherein X is a halide; (ii) passing the raw synthesis gas through a water gas shift reactor (WGSR) into which CaO and steam are injected, the CaO reacting with the shifted gas to remove CO.sub.2, sulfur and halides in a solid-phase calcium-containing product comprising CaCO.sub.3, CaS and CaX.sub.2; (iii) separating the solid-phase calcium-containing product from an enriched gaseous hydrogen product; and (iv) regenerating the CaO by calcining the solid-phase calcium-containing product at a condition selected from the group consisting of: in the presence of steam, in the presence of CO.sub.2, in the presence of synthesis gas, in the presence of H.sub.2 and O.sub.2, under partial vacuum, and combinations thereof.

  2. Calcium looping process for high purity hydrogen production integrated with capture of carbon dioxide, sulfur and halides

    DOEpatents

    Ramkumar, Shwetha; Fan, Liang-Shih

    2013-07-30

    A process for producing hydrogen comprising the steps of: (i) gasifying a fuel into a raw synthesis gas comprising CO, hydrogen, steam, sulfur and halide contaminants in the form of H.sub.2S, COS, and HX, wherein X is a halide; (ii) passing the raw synthesis gas through a water gas shift reactor (WGSR) into which CaO and steam are injected, the CaO reacting with the shifted gas to remove CO.sub.2, sulfur and halides in a solid-phase calcium-containing product comprising CaCO.sub.3, CaS and CaX.sub.2; (iii) separating the solid-phase calcium-containing product from an enriched gaseous hydrogen product; and (iv) regenerating the CaO by calcining the solid-phase calcium-containing product at a condition selected from the group consisting of: in the presence of steam, in the presence of CO.sub.2, in the presence of synthesis gas, in the presence of H.sub.2 and O.sub.2, under partial vacuum, and combinations thereof.

  3. Sulfuric acid poisoning

    MedlinePlus

    Sulfuric acid is a very strong chemical that is corrosive. Corrosive means it can cause severe burns and ... or mucous membranes. This article discusses poisoning from sulfuric acid. This article is for information only. Do NOT ...

  4. The Sulfur Cycle

    ERIC Educational Resources Information Center

    Kellogg, W. W.; And Others

    1972-01-01

    A model estimating the contributions of sulfur compounds by natural and human activities, and the rate of removal of sulfur from the atmosphere, is based on a review of the existing literature. Areas requiring additional research are identified. (AL)

  5. Sulfur and oxygen isotope study of the Vermont copper belt: evidence of seawater hydrothermal alteration and sulfate reduction in a high-grade metamorphic terrane

    SciTech Connect

    Shanks, W.C. III; Woodruff, L.G.; Slack, J.F.

    1985-01-01

    Massive sulfide deposits of the Orange County copper district, in east-central Vermont, consist of stratiform lenses of pyrrhotite, chalcopyrite, and minor sphalerite within amphibolite-facies rocks of Early Devonian (.) age. The deposits occur at several different stratigraphic levels. The two largest, Elizabeth and Ely, are in quartz-mica schists of the Gile Mountain Formation; the Pike Hill deposit occurs in calcareous quartz-mica schist of the underlying Waits River Formation. Two small deposits (Orange and Gove) are within the Standing Pond Volcanics, a thin tholeiitic amphibolite near the Gile Mountain-Waits River contact. The Elizabeth deposit in particularly distinctive, and contains a suite of unusual wall rocks rich in quartz, carbonate, muscovite, amphibole, phlogopite, tourmaline, spessartine, and sodic plagioclase. Sulfur isotope values at Elizabeth and Ely of 5.1 to 9.1 per thousands contrast with values for Gove (1.9 to 4.2) and Pike Hill (1.5 to 4.6). Disseminated sulfides in amphibolites of the Standing Pond Volcanics have sulfur isotope values in the range -0.1 to 1.7 per thousands, typical of MORB. These data require sulfur contributions to massive sulfide deposits both from basalt and from contemporaneous seawater sulfate sources. Whole-rock (carbonate free) oxygen isotope analyses of host lithologies range from 7.9 per thousands (Standing Pond Volcanics) to 19.9 per thousands (Waits River Formation). Detailed sampling of Elizabeth wall rocks (including those high in B, Na, Mg, Al, Si, Mn) yields a narrow range of oxygen isotope values (11.1 to 14.1); heavier values correlate with higher silica contents. Isotopically light wallrock lithologies are probably due to premetamorphic seawater hydrothermal alteration.

  6. Observation of new particle formation and measurement of sulfuric acid, ammonia, amines and highly oxidized organic molecules at a rural site in central Germany

    NASA Astrophysics Data System (ADS)

    Kürten, Andreas; Bergen, Anton; Heinritzi, Martin; Leiminger, Markus; Lorenz, Verena; Piel, Felix; Simon, Mario; Sitals, Robert; Wagner, Andrea C.; Curtius, Joachim

    2016-10-01

    The exact mechanisms for new particle formation (NPF) under different boundary layer conditions are not known yet. One important question is whether amines and sulfuric acid lead to efficient NPF in the atmosphere. Furthermore, it is not clear to what extent highly oxidized organic molecules (HOMs) are involved in NPF. We conducted field measurements at a rural site in central Germany in the proximity of three larger dairy farms to investigate whether there is a connection between NPF and the presence of amines and/or ammonia due to the local emissions from the farms. Comprehensive measurements using a nitrate chemical ionization-atmospheric pressure interface time-of-flight (CI-APi-TOF) mass spectrometer, a proton-transfer-reaction mass spectrometer (PTR-MS), particle counters and differential mobility analyzers (DMAs), as well as measurements of trace gases and meteorological parameters, were performed. We demonstrate here that the nitrate CI-APi-TOF is suitable for sensitive measurements of sulfuric acid, amines, a nitrosamine, ammonia, iodic acid and HOMs. NPF was found to correlate with sulfuric acid, while an anti-correlation with RH, amines and ammonia is observed. The anti-correlation between NPF and amines could be due to the efficient uptake of these compounds by nucleating clusters and small particles. Much higher HOM dimer (C19/C20 compounds) concentrations during the night than during the day indicate that these HOMs do not efficiently self-nucleate as no nighttime NPF is observed. Observed iodic acid probably originates from an iodine-containing reservoir substance, but the iodine signals are very likely too low to have a significant effect on NPF.

  7. Prevention of sulfur diffusion using MoS2-intercalated 3D-nanostructured graphite for high-performance lithium-ion batteries.

    PubMed

    Tiwari, Anand P; Yoo, HeeJoun; Lee, JeongTaik; Kim, Doyoung; Park, Jong Hyeok; Lee, Hyoyoung

    2015-07-28

    We report new three-dimensional (3D)-nanostructured MoS2-carbonaceous materials in which MoS2 sheets are intercalated between the graphite layers that possess a multiply repeated graphite/MoS2/graphite structure which prevents the aggregation of MoS2 and diffusion of sulfur from carbonaceous materials, enhancing the cycling stability of Li-ion batteries. We developed an efficient and scalable process applicable to mass production for synthesizing non-aggregated MoS2-intercalated 3D hybrid-nanostructured graphite based on stress induced and microwave irradiation. X-ray diffraction, X-ray photospectroscopy, Raman spectroscopy, field emission scanning electron microscopy, and high-resolution transmission electron microscopy analyses demonstrated that the as-synthesized materials consisted of MoS2-intercalated 3D hybrid-nanostructured graphite platelets that had a multiply repeated graphite/MoS2/graphite structure. The obtained MoS2-graphite powder surpasses MoS2 as an anode material in terms of specific capacity, cyclic stability, and rate performances at high current densities for Li-ion batteries. The electrochemical impedance spectroscopy demonstrated that the graphite sheets not only reduced the contact resistance in the electrode but also facilitated electron transfer in the lithiation/delithiation processes. The superior electrochemical performances especially for the cycling stability of the Li-ion battery originate from prevention of the sulfur diffusion of the MoS2-intercalated 3D-nanostructured graphite.

  8. Determination of sulfur in crude oil using high-resolution continuum source molecular absorption spectrometry of the SnS molecule in a graphite furnace.

    PubMed

    Cadorim, Heloisa R; Pereira, Éderson R; Carasek, Eduardo; Welz, Bernhard; de Andrade, Jailson B

    2016-01-01

    An analytical method for the determination of sulfur, as the tin mono-sulfide (SnS) molecule, in crude oil using high-resolution continuum source graphite furnace molecular absorption spectrometry (HR-CS GF MAS) has been developed. The molecular absorbance of the SnS has been measured using the wavelength at 271.624 nm and the crude oil samples were prepared as micro-emulsions due to their high viscosity. Several chemical modifiers (Ir, Pd, Ru, Zr) were tested and palladium was chosen, because it exhibited the best performance. The heating program was optimized by comparing the pyrolysis and vaporization curves obtained for an aqueous sulfur standard and a micro-emulsion of a crude oil certified reference material (CRM). The optimum pyrolysis and vaporization temperatures were found to be 600 and 2000°C, respectively. The limit of detection and the characteristic mass using micro-emulsion analysis of crude oil samples were 5.8 and 13.3 ng S. Accuracy and precision of the method has been evaluated using two crude oil CRM (NIST 2721 and NIST 2722), showing good agreement with the informed or certified values.

  9. 3D-hybrid material design with electron/lithium-ion dual-conductivity for high-performance Li-sulfur batteries

    NASA Astrophysics Data System (ADS)

    Zhao, Yan; Tan, Rui; Yang, Jie; Wang, Kai; Gao, Rongtan; Liu, Dong; Liu, Yidong; Yang, Jinlong; Pan, Feng

    2017-02-01

    We report a novel 3D-hybrid cathode material with three-dimensional (3D) N-GO/CNT framework to load sulfur (77.6 wt %), and sulfonated polyaniline (SPANI) of coating layer. Used as a cathode material, it possesses a high capacity (1196 mAh g-1@0.3 A g-1@1.6 mg cm-2), excellent charging-discharging rate (680 mAh g-1@7.5 A g-1) and long-life performance (maintaining 71.1% capacity over 450 cycles), which is mainly attributed to the benefits of excellent electronic/Li-ionic dual-conductivity and confinement effect of the 3D-hybrid N-GO/CNT framework coated by self-doping conducting polymer SPANI. Thus, a 3D sulfur cathode modified with electronic/Li-ionic dual-conduction network can significantly enhance the electrochemical performance and stability, and this novel type of material is very promising for commercial applications that require high energy and power density, long life, and excellent abuse tolerance.

  10. High-molecular weight sulfur-containing aromatics refractory to weathering as determined by Fourier transform ion cyclotron resonance mass spectrometry.

    PubMed

    Hegazi, Abdelrahman H; Fathalla, Eiman M; Panda, Saroj K; Schrader, Wolfgang; Andersson, Jan T

    2012-09-01

    Biomarkers and low-molecular weight polyaromatic compounds have been extensively studied for their fate in the environment. They are used for oil spill source identification and monitoring of weathering and degradation processes. However, in some cases, the absence or presence of very low concentration of such components restricts the access of information to spill source. Here we followed the resistance of high-molecular weight sulfur-containing aromatics to the simulated weathering condition of North Sea crude oil by ultra high-resolution Fourier transform ion cyclotron resonance mass spectrometry. The sulfur aromatics in North Sea crude having double bond equivalents (DBE) from 6 to 14 with a mass range 188-674Da were less influenced even after 6 months artificial weathering. Moreover, the ratio of dibenzothiophenes (DBE 9)/naphthenodibenzothiophenes (DBE 10) was 1.30 and 1.36 in crude oil and 6 months weathered sample, respectively reflecting its weathering stability. It also showed some differences within other oils. Hence, this ratio can be used as a marker of the studied crude and accordingly may be applied for spilled oil source identification in such instances where the light components have already been lost due to environmental influences.

  11. Pudding-typed cobalt sulfides/nitrogen and sulfur dual-doped hollow carbon spheres as a highly efficient and stable oxygen reduction electrocatalyst

    NASA Astrophysics Data System (ADS)

    Xiao, Junwu; Zhao, Chen; Hu, Chencheng; Xi, Jiangbo; Wang, Shuai

    2017-04-01

    Metal organic frameworks (MOFs) are rarely reported to be grown at the templates due to the strong inherent driving force for crystallization. Herein, we report a pathway to successfully synthesize Zeolitic imidazolate framework-67 (ZIF-67) grown at the unmodified SiO2 spheres from amorphous precursors, and further construct Pudding-typed electrocatalysts, where cobalt sulfides (CoSx) nanocrystals are embedded into nitrogen and sulfur dual-doped hollow carbon spheres (N, S-HCS). CoSx/N, S-HCS show good catalytic activity toward the oxygen reduction reaction (ORR), and the optimized performance is achieved with (CoSx/N, S-HCS)700 with the positive half-wave potentials of 0.90 V vs RHE, high selectivity, good long-term stability, and excellent tolerance against methanol-crossover effect in alkaline medium, which are even superior to that of the as-reported MOFs-derived catalysts and commercial Pt/C catalysts. The remarkable catalytic performance is originated from high reactivity of catalytic active sites composed of cobalt sulfides and nitrogen and sulfur dual-doped carbon matrices, and Pudding-typed hollow structure with proper graphitization degree to facilitate fast electron and ion transport and limit the dissolution and agglomeration of active sites during long-term operation.

  12. A Carbon-Sulfur Hybrid with Pomegranate-like Structure for Lithium-Sulfur Batteries.

    PubMed

    Shi, Yanting; Lv, Wei; Niu, Shuzhang; He, Yanbing; Zhou, Guangmin; Chen, Guohua; Li, Baohua; Yang, Quan-Hong; Kang, Feiyu

    2016-05-06

    A carbon-sulfur hybrid with pomegranate-like core-shell structure, which demonstrates a high rate performance and relatively high cyclic stability, is obtained through carbonization of a carbon precursor in the presence of a sulfur precursor (FeS2 ) and a following oxidation of FeS2 to sulfur by HNO3 . Such a structure effectively protects the sulfur and leaves enough buffer space after Fe(3+) removal and, at the same time, has an interconnected conductive network. The capacity of the obtained hybrid is 450 mA h g(-1) under the current density of 5 C. This work provides a simple strategy to design and prepare various high-performance carbon-sulfur hybrids for lithium-sulfur batteries.

  13. Sulfuric acid on Europa and the radiolytic sulfur cycle

    NASA Technical Reports Server (NTRS)

    Carlson, R. W.; Johnson, R. E.; Anderson, M. S.

    1999-01-01

    A comparison of laboratory spectra with Galileo data indicates that hydrated sulfuric acid is present and is a major component of Europa's surface. In addition, this moon's visually dark surface material, which spatially correlates with the sulfuric acid concentration, is identified as radiolytically altered sulfur polymers. Radiolysis of the surface by magnetospheric plasma bombardment continuously cycles sulfur between three forms: sulfuric acid, sulfur dioxide, and sulfur polymers, with sulfuric acid being about 50 times as abundant as the other forms. Enhanced sulfuric acid concentrations are found in Europa's geologically young terrains, suggesting that low-temperature, liquid sulfuric acid may influence geological processes.

  14. Sulfuric acid on Europa and the radiolytic sulfur cycle.

    PubMed

    Carlson, R W; Johnson, R E; Anderson, M S

    1999-10-01

    A comparison of laboratory spectra with Galileo data indicates that hydrated sulfuric acid is present and is a major component of Europa's surface. In addition, this moon's visually dark surface material, which spatially correlates with the sulfuric acid concentration, is identified as radiolytically altered sulfur polymers. Radiolysis of the surface by magnetospheric plasma bombardment continuously cycles sulfur between three forms: sulfuric acid, sulfur dioxide, and sulfur polymers, with sulfuric acid being about 50 times as abundant as the other forms. Enhanced sulfuric acid concentrations are found in Europa's geologically young terrains, suggesting that low-temperature, liquid sulfuric acid may influence geological processes.

  15. High protists diversity in the plankton of sulfurous lakes and lagoons examined by 18s rRNA gene sequence analyses.

    PubMed

    Triadó-Margarit, Xavier; Casamayor, Emilio O

    2015-12-01

    Diversity of small protists was studied in sulfidic and anoxic (euxinic) stratified karstic lakes and coastal lagoons by 18S rRNA gene analyses. We hypothesized a major sulfide effect, reducing protist diversity and richness with only a few specialized populations adapted to deal with low-redox conditions and high-sulfide concentrations. However, genetic fingerprinting suggested similar ecological diversity in anoxic and sulfurous than in upper oxygen rich water compartments with specific populations inhabiting euxinic waters. Many of them agreed with genera previously identified by microscopic observations, but also new and unexpected groups were detected. Most of the sequences matched a rich assemblage of Ciliophora (i.e., Coleps, Prorodon, Plagiopyla, Strombidium, Metopus, Vorticella and Caenomorpha, among others) and algae (mainly Cryptomonadales). Unidentified Cercozoa, Fungi, Stramenopiles and Discoba were recurrently found. The lack of GenBank counterparts was higher in deep hypolimnetic waters and appeared differentially allocated in the different taxa, being higher within Discoba and lower in Cryptophyceae. A larger number of populations than expected were specifically detected in the deep sulfurous waters, with unknown ecological interactions and metabolic capabilities.

  16. Demonstration of selective catalytic reduction technology for the control of nitrogen oxide emissions from high-sulfur, coal-fired boilers

    SciTech Connect

    Hinton, W.S.; Powell, C.A.; Maxwell, J.D.

    1993-11-01

    This paper describes the status of the Innovative Clean Coal Technology project to demonstrate SCR technology for reduction of NO{sub x} emissions from flue gas of utility boilers burning US high-sulfur coal. The funding participants are the US Department of Energy (DOE), Southern Company Services, Inc. (SCS), on behalf of the entire Southern Company, Electric Power Research Institute (EPRI), and Ontario Hydro. SCS is the participant responsible for managing all aspects of the project. The project is being conducted on Gulf Power Company`s Plant Crist Unit 5 (75-MW nominal capacity), located near Pensacola, Florida, on US coals that have a sulfur content near 3.0%. The SCR facility treats a 17,400 scfm slip-stream of flue gas and consists of three 2.5-MW (5000 scfm) and six 0.2-MW (400 scfm) SCR reactors. The reactors operate in parallel with commercially available SCR catalysts obtained from vendors throughout the world. The design engineering and construction have been completed, and the startup/shakedown was completed in June 1993. Long-term performance testing began in July 1993 and will be conducted for two years. Test facility description and test plans, as well as start-up issues and preliminary commissioning test results are reported in this paper.

  17. Sulfur tolerant anode materials

    SciTech Connect

    Not Available

    1988-02-01

    The goal of this program is the development of a molten carbonate fuel cell (MCFC) anode which is more tolerant of sulfur contaminants in the fuel than the current state-of-the-art nickel-based anode structures. This program addresses two different but related aspects of the sulfur contamination problem. The primary aspect is concerned with the development of a sulfur tolerant electrocatalyst for the fuel oxidation reaction. A secondary issue is the development of a sulfur tolerant water-gas-shift reaction catalyst and an investigation of potential steam reforming catalysts which also have some sulfur tolerant capabilities. These two aspects are being addressed as two separate tasks.

  18. Aqueous synthesis of Cu-doped ZnCdS/ZnS core/shell nanocrystals with a new and highly reactive sulfur source

    NASA Astrophysics Data System (ADS)

    Zeng, Ruosheng; Shen, Rongan; Zhao, Yunqiang; Li, Xingsheng; Sun, Zhiguo; Shen, Yayun

    2014-04-01

    A new sulfur precursor with a highly reactive chemical nature was prepared with S powder and NaBH4 at the high temperature of 180 °C in a closed autoclave and made it possible to carry out the synthesis of high quality metal sulfide nanocrystals (NCs) with diverse composition and structure. Using this new sulfur source, we demonstrated aqueous synthesis of colloidal Cu-doped ZnCdS NCs (d-dots) with pure, color-tunable photoluminescence (PL) in a wide spectral range (from 517 to 650 nm) based on the ‘co-nucleation doping’ strategy. The influences of the various experimental variables, including Cd/Zn ratio, Cu-doping concentration, pH value and amount of mercaptopropionic acid (MPA), on the optical properties of Cu-doped ZnCdS NCs were systematically investigated. Furthermore, highly efficient and stable dopant emission from Cu:ZnCdS/ZnS core/shell d-dots with PL quantum yield as high as 40% was achieved by the deposition of a ZnS shell around the bare Cu:ZnCdS cores; this is the highest reported to date for aqueous doped NCs. The optical properties and structure of the d-dots were characterized by UV-vis absorption spectra, PL spectra, x-ray photoelectron spectroscopy, powder x-ray diffraction, and transmission electron microscopy. The experimental results indicated that this facile synthesis route would provide a versatile approach for the preparation of other water-soluble sulfide NCs.

  19. Dose Response of MTLn3 Cells to Serial Dilutions of Arsenic Trioxide and Ionizing Radiation.

    PubMed

    Raja, Waseem Khan; Satti, Jahangir; Liu, Gang; Castracane, James

    2013-01-01

    MTLn3 cells derived from mouse mammary epithelium are known to be highly malignant and are resistant to both radio- and chemo-therapy. We exposed MTLn3 cells to various doses of inorganic Arsenic trioxide (As2O3) in combination with ionizing radiation. Cells were treated with a series of As2O3 concentrations ranging from 20 μM to 1.22 nM for 8 hour, 24 hour and 48 hour periods. Post-treated cell proliferation was quantified by measuring mitochondrial activity and DNA analysis. Cells exposed to radiation and As2O3 at concentration greater than 1.25 μM showed apoptosis and radiations alone treated cells were statistically not different from the control. Hormesis was observed for As2O3 concentrations in the range of 0.078 μM to 0.625 μM while the combined chemo and radiation treatments of the cells did not affect the hormetic effect. We have demonstrated that As2O3 (in the presence and absence of ionizing radiation) in specific low concentrations induced apoptosis in the otherwise chemoresistant cancer cells. This low concentration-mediated cell death is immediately followed by a surge in cell survival. Low dosing dosimetry is highly desirable in metronomic therapy however, it has a narrow window since necrosis, hormesis, apoptosis and other dose-dependent biological processes take place in this region. Further quantifiable dosimetry is highly desired for routine clinical practice.

  20. Sulfur-Immobilized, Activated Porous Carbon Nanotube Composite Based Cathodes for Lithium-Sulfur Batteries.

    PubMed

    Lee, Jun Seop; Jun, Jaemoon; Jang, Jyongsik; Manthiram, Arumugam

    2017-03-01

    Activated highly porous carbon nanotubes are synthesized with a facile dual-nozzle co-electrospinning and a redox process to apply the framework of a sulfur-immobilized composite as a high-performance cathode in lithium-sulfur batteries.

  1. Significantly improved long-cycle stability in high-rate Li-S batteries enabled by coaxial graphene wrapping over sulfur-coated carbon nanofibers.

    PubMed

    Lu, Songtao; Cheng, Yingwen; Wu, Xiaohong; Liu, Jie

    2013-06-12

    Long-term instability of Li-S batteries is one of their major disadvantages compare to other secondary batteries. The reasons for the instability include dissolution of polysulfide intermediates and mechanical instability of the electrode film caused by volume changes during charging/discharging cycles. In this paper, we report a novel graphene-sulfur-carbon nanofibers (G-S-CNFs) multilayer and coaxial nanocomposite for the cathode of Li-S batteries with increased capacity and significantly improved long-cycle stability. Electrodes made with such nanocomposites were able to deliver a reversible capacity of 694 mA h g(-1) at 0.1C and 313 mA h g(-1) at 2C, which are both substantially higher than electrodes assembled without graphene wrapping. More importantly, the long-cycle stability was significantly improved by graphene wrapping. The cathode made with G-S-CNFs with a initial capacity of 745 mA h g(-1) was able to maintain ~273 mA h g(-1) even after 1500 charge-discharge cycles at a high rate of 1C, representing an extremely low decay rate (0.043% per cycle after 1500 cycles). In contrast, the capacity of an electrode assembled without graphene wrapping decayed dramatically with a 10 times high rate (~0.40% per cycle after 200 cycles). These results demonstrate that the coaxial nanocomposites are of great potential as the cathode for high-rate rechargeable Li-S batteries. Such improved rate capability and cycle stability could be attributed to the unique coaxial architecture of the nanocomposite, in which the contributions from graphene and CNFs enable electrodes with improved electrical conductivity, better ability to trap soluble the polysulfides intermediate and accommodate volume expansion/shrinkage of sulfur during repeated charge/discharge cycles.

  2. Effect of sulfur content in a sulfur-activated carbon composite on the electrochemical properties of a lithium/sulfur battery

    SciTech Connect

    Park, Jin-Woo; Kim, Changhyeon; Ryu, Ho-Suk; Cho, Gyu-Bong; Cho, Kwon-Koo; Kim, Ki-Won; Ahn, Jou-Hyeon; Wang, Guoxiu; Ahn, Jae-Pyeung; Ahn, Hyo-Jun

    2015-09-15

    Highlights: • The content of sulfur in activated carbon was controlled by solution process. • The sulfur electrode with low sulfur content shows the best performance. • The Li/S battery has capacity of 1360 mAh/g at 1 C and 702 mAh/g at 10 C. - Abstract: The content of sulfur in sulfur/activated carbon composite is controlled from 32.37 wt.% to 55.33 wt.% by a one-step solution-based process. When the sulfur content is limited to 41.21 wt.%, it can be loaded into the pores of an activated carbon matrix in a highly dispersed state. On the contrary, when the sulfur content is 55.33 wt.%, crystalline sulfur can be detected on the surface of the activated carbon matrix. The best electrochemical performance can be obtained for a sulfur electrode with the lowest sulfur content. The sulfur/activated carbon composite with 32.37 wt.% sulfur afforded the highest first discharge capacity of 1360 mAh g{sup −1} at 1 C rate and a large reversible capacity of 702 mAh g{sup −1} at 10 C (16.75 A/g)

  3. High archaeal richness in the water column of a freshwater sulfurous karstic lake along an interannual study.

    PubMed

    Llirós, Marc; Casamayor, Emilio O; Borrego, Carles

    2008-11-01

    We surveyed the archaeal assemblage in a stratified sulfurous lake (Lake Vilar, Banyoles, Spain) over 5 consecutive years to detect potential seasonal and interannual trends in the free-living planktonic Archaea composition. The combination of different primer pairs and nested PCR steps revealed an unexpectedly rich archaeal community. Overall, 140 samples were analyzed, yielding 169 different 16S rRNA gene sequences spread over 14 Crenarchaeota (109 sequences) and six Euryarchaeota phylogenetic clusters. Most of the Crenarchaeota (98% of the total crenarchaeotal sequences) affiliated within the Miscellaneous Crenarchaeota Group (MCG) and were related to both marine and freshwater phylotypes. Euryarchaeota mainly grouped within the Deep Hydrothermal Vent Euryarchaeota (DHVE) cluster (80% of the euryarchaeotal sequences) and the remaining 20% distributed into three less abundant taxa, most of them composed of soil and sediment clones. The largest fraction of phylotypes from the two archaeal kingdoms (79% of the Crenarchaeota and 54% of the Euryarchaeota) was retrieved from the anoxic hypolimnion, indicating that these cold and sulfide-rich waters constitute an unexplored source of archaeal richness. The taxon rank-frequency distribution showed two abundant taxa (MCG and DHVE) that persisted in the water column through seasons, plus several rare ones that were only detected occasionally. Differences in richness distribution and seasonality were observed, but no clear correlations were obtained when multivariate statistical analyses were carried out.

  4. Extraction, separation and analysis of high sulfur coal. Technical progress report No. 11, January 1, 1990--March 21, 1990

    SciTech Connect

    Olesik, S.V.

    1990-04-02

    In summary, significant bond cleavage was found only for thiophenol under the supercritical conditions studied. Less than 5% yield was found for the observed reaction products for all the other organosulfur compounds. The hydrogen sulfur bond in thiophenol is clearly the weakest of those studied and therefore it is the easiest to rupture. Also a general trend was observed the solvolysis reaction products such as ethylthiobenzene were the products initially formed at lower temperatures. But with higher temperatures the reaction product were those typically produced from the bimolecular association of free-radicals, such as phenylsulfide for the thiophenol sample. This type of reaction would be expected in pyrolysis reactions. Bimolecular reactions between organosulfur compounds would not be expected when the reaction is occurring at the surface of the solid coal matrix. The probability of the extracted organosulfur radicals having such bimolecular reactions is quite low. However, the reactions that are observed from the interaction of supercritical ethanol and the model coal compounds are not ones that show obvious indications of desulfurization of the compound.

  5. Organic reactions catalyzed by methylrhenium trioxide: Reactions of ethyl diazoacetate and organic azides

    SciTech Connect

    Zhu, Z.; Espenson, J.H. |

    1996-10-16

    Methylrhenium trioxide (CH{sub 3}ReO{sub 3} or MTO) catalyzes several classes of reactions of ethyl diazoacetate, EDA. It is the first high valent oxo complex for carbene transfer. Under mild conditions and in the absence of other substrates, EDA was converted to a 9:1 mixture of diethyl maleate and diethyl fumarate. In the presence of alcohols, {alpha}-alkoxy ethyl acetates were obtained in good yield. The yields dropped for the larger and more branched alcohols, the balance of material being diethyl maleate and fumarate. An electron-donating group in the para position of phenols favors the formation of {alpha}-phenoxy ethyl acetates. The use of EDA to form {alpha}-thio ethyl acetates and N-substituted glycine ethyl esters, on the other hand, is hardly affected by the size or structure of the parent thiol or amine, with all of these reactions proceeding in high yield. MTO-catalyzed cycloaddition reactions occur between EDA and aromatic imines, olefins, and carbonyl compounds. Three-membered ring products are formed: aziridines, cyclopropanes, and epoxides, respectively. The reactions favor the formation of trans products, and provide a convenient route for the preparation of aziridines. Intermediate carbenoid and nitrenoid species have been proposed. In the presence of an oxygen source such as an epoxide, ethyl diazoacetate and azibenzil are converted to an oxalic acid monoethyl ester and to benzil; at the same time the epoxide was converted to an olefin. 75 refs., 1 fig., 7 tabs.

  6. Successful apexification with resolution of the periapical lesion using mineral trioxide aggregate and demineralized freeze-dried bone allograft

    PubMed Central

    Chhabra, Naveen; Singbal, Kiran P; Kamat, Sharad

    2010-01-01

    Immature teeth with necrotic pulp and large periapical lesion are difficult to treat via conventional endodontic therapy. The role of materials such as calcium hydroxide and mineral trioxide aggregate in apexification is indispensable. This case report presents the successful healing and apexification with combined use of white mineral trioxide aggregate and demineralized freeze-dried bone allograft. PMID:20859486

  7. The Low-temperature Ion Sulfurizing Technology and its Applications

    NASA Astrophysics Data System (ADS)

    Ma, G. Z.; Xu, B. S.; Wang, H. D.; Li, G. L.; Zhang, S.

    A solid lubrication film mainly consists of FeS, which has excellent tribology properties, can be formed on the sulfurized iron or steel surface. The sulfurizing technology has aroused intense attention from the day it appeared. However, the widespread industrial application of sulfurizing technology was promoted by the low-temperature ion sulfurizing (LTIS) process. This paper summarized the phylogeny and sorts of sulfurizing technology firstly; then, the process flow of LTIS technology, the forming mechanism, microstructure and tribological properties of ion sulfurized layer were introduced detailedly; and then, the technological, economic and environmental merits of LTIS technology were generalized; finally, the industrial applications of LTIS technology in various typical rolling, sliding and heavy duty parts were reviewed briefly. LTIS technology, with the advantages of high sulfurizing speed, good performance of sulfurized layer and without sideeffect, has played an important role in the tribology modification of ferrous parts, and the LTIS process will become more green, simple and efficient in the future.

  8. Prevention of sulfur diffusion using MoS2-intercalated 3D-nanostructured graphite for high-performance lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Tiwari, Anand P.; Yoo, Heejoun; Lee, Jeongtaik; Kim, Doyoung; Park, Jong Hyeok; Lee, Hyoyoung

    2015-07-01

    We report new three-dimensional (3D)-nanostructured MoS2-carbonaceous materials in which MoS2 sheets are intercalated between the graphite layers that possess a multiply repeated graphite/MoS2/graphite structure which prevents the aggregation of MoS2 and diffusion of sulfur from carbonaceous materials, enhancing the cycling stability of Li-ion batteries. We developed an efficient and scalable process applicable to mass production for synthesizing non-aggregated MoS2-intercalated 3D hybrid-nanostructured graphite based on stress induced and microwave irradiation. X-ray diffraction, X-ray photospectroscopy, Raman spectroscopy, field emission scanning electron microscopy, and high-resolution transmission electron microscopy analyses demonstrated that the as-synthesized materials consisted of MoS2-intercalated 3D hybrid-nanostructured graphite platelets that had a multiply repeated graphite/MoS2/graphite structure. The obtained MoS2-graphite powder surpasses MoS2 as an anode material in terms of specific capacity, cyclic stability, and rate performances at high current densities for Li-ion batteries. The electrochemical impedance spectroscopy demonstrated that the graphite sheets not only reduced the contact resistance in the electrode but also facilitated electron transfer in the lithiation/delithiation processes. The superior electrochemical performances especially for the cycling stability of the Li-ion battery originate from prevention of the sulfur diffusion of the MoS2-intercalated 3D-nanostructured graphite.We report new three-dimensional (3D)-nanostructured MoS2-carbonaceous materials in which MoS2 sheets are intercalated between the graphite layers that possess a multiply repeated graphite/MoS2/graphite structure which prevents the aggregation of MoS2 and diffusion of sulfur from carbonaceous materials, enhancing the cycling stability of Li-ion batteries. We developed an efficient and scalable process applicable to mass production for synthesizing non

  9. Application of indigenous sulfur-oxidizing bacteria from municipal wastewater to selectively bioleach phosphorus from high-phosphorus iron ore: effect of particle size.

    PubMed

    Shen, Shaobo; Rao, Ruirui; Wang, Jincao

    2013-01-01

    The effects of ore particle size on selectively bioleaching phosphorus (P) from high-phosphorus iron ore were studied. The average contents of P and Fe in the iron ore were 1.06 and 47.90% (w/w), respectively. The particle sizes of the ores used ranged from 58 to 3350 microm. It was found that the indigenous sulfur-oxidizing bacteria from municipal wastewater could grow well in the slurries of solid high-phosphorus iron ore and municipal wastewater. The minimum bioleaching pH reached for the current work was 0.33. The P content in bioleached iron ore reduced slightly with decreasing particle size, while the removal percentage of Fe decreased appreciably with decreasing particle size. The optimal particle size fraction was 58-75 microm, because the P content in bioleached iron ore reached a minimum of 0.16% (w/w), the removal percentage of P attained a maximum of 86.7%, while the removal percentage of Fe dropped to a minimum of 1.3% and the Fe content in bioleached iron ore was a maximum of 56.4% (w/w) in this case. The iron ores thus obtained were suitable to be used in the iron-making process. The removal percentage of ore solid decreased with decreasing particle size at particle size range of 106-3350 microm. The possible reasons resulting in above phenomena were explored in the current work. It was inferred that the particle sizes of the iron ore used in this work have no significant effect on the viability of the sulfur-oxidizing bacteria.

  10. Uranium trioxide behavior during electron energy loss spectroscopy analysis

    NASA Astrophysics Data System (ADS)

    Degueldre, Claude; Alekseev, Evgeny V.

    2015-03-01

    A sample of uranium trioxide (UO3) was produced by focused ion beam (~10 μm×~10 μm×<0.5 μm) for transmission electron and electron energy loss (EEL) spectroscopy examinations in a transmission electron microscope (TEM). The EEL spectra were recorded as a function of the thickness for the P and O edges in the low energy range 0-350 eV and were compared to spectra of UO3 small grains attached to a TEM grid. The EEL spectrum was studied through a range of thicknesses going from ~60 to ~260 nm. The EEL spectra recorded for UO3 are compared with those recorded for UO2. The reduction of UO3 into U4O9 and/or UO2 is readily observed apparently during the TEM investigations and as confirmed by electron diffraction (eD). This redox effect is similar to that known for other redox sensitive oxides. Recommendations are suggested to avoid sample decomposition.

  11. Kinetics and mechanism of photopromoted oxidative dissolution of antimony trioxide.

    PubMed

    Hu, Xingyun; Kong, Linghao; He, Mengchang

    2014-12-16

    Light (sunlight, ultraviolet, simulated sunlight) irradiation was used to initiate the dissolution of antimony trioxide (Sb2O3). Dissolution rate of Sb2O3 was accelerated and dissolved trivalent antimony (Sb(III)) was oxidized in the irradiation of light. The photopromoted oxidative dissolution mechanism of Sb2O3 was studied through experiments investigating the effects of pH, free radicals scavengers, dissolved oxygen removal and Sb2O3 dosage on the release rate of antimony from Sb2O3 under simulated sunlight irradiation. The key oxidative components were hydroxyl free radicals, photogenerated holes and superoxide free radicals; their contribution ratios were roughly estimated. In addition, a conceptual model of the photocatalytic oxidation dissolution of Sb2O3 was proposed. The overall pH-dependent dissolution rate of Sb2O3 and the oxidation of Sb(III) under light irradiation were expressed by r = 0.08 ·[OH(-)](0.63) and rox = 0.10 ·[OH(-)](0.79). The present study on the mechanism of the photo-oxidation dissolution of Sb2O3 could help clarify the geochemical cycle and fate of Sb in the environment.

  12. Compressive Strength of Mineral Trioxide Aggregate with Propylene Glycol

    PubMed Central

    Ghasemi, Negin; Rahimi, Saeed; Shahi, Shahriar; Salem Milani, Amin; Rezaei, Yashar; Nobakht, Mahnaz

    2016-01-01

    Introduction: The aim of this study was to evaluate the effect of adding propylene glycol (PG) to mineral trioxide aggregate (MTA) liquid with volume ratio of 20% on the compressive strength (CS) of MTA in two time periods (4 and 21 days) after mixing. Methods and Materials: Four groups of steel cylinders (n=15) with an internal diameter of 3 and a height of 6 mm were prepared and MTA (groups 1 and 2) and MTA+PG (80% MTA liquid+20% PG) (groups 3 and 4) were placed in to the cylinders. In groups 1 and 3 the CS was evaluated after 4 days and in groups 2 and 4 after 21 days. Data were calculated using the two-ways ANOVA. The level of significance was set at 0.05. Results: The highest (52.22±18.92 MPa) and lowest (4.5±0.67 MPa) of CS was obtained in 21-day MTA samples and 4-day MTA+PG specimen, respectively. The effect of time and PG were significant on the CS (P<0.05). Mixing MTA with PG significantly reduced the CS; but passing the time from 4 to 21 days significantly increased the CS. Conclusion: Considering the limitations of this study, PG had a negative effect on CS of MTA. PMID:27790264

  13. Effects of variation of dietary sulfur on movement of sulfur in sheep rumen

    SciTech Connect

    Kandylis, K.; Bray, A.C.

    1987-01-01

    Effects of variations in dietary sulfur on rumen sulfur dynamics were studied under steady state conditions. In the first experimental period, three sheep were given 33.3 g of a pelleted diet hourly containing 1.59 g sulfur/kg (low) and in the second period the sulfur content was increased to 3.21 g/kg (high) by the addition of sodium sulfate. The daily sulfur intake was 1.158 g on the low sulfur diet and .545 g of this passed from the rumen in protein, .614 g was calculated to be absorbed from the rumen as sulfide, and .052 g was estimated to be recycled to the rumen. For sheep with daily intakes of 2.317 g sulfur, 1.212 g passed from the rumen in protein, 1.078 g was absorbed from the rumen, and .093 g was estimated to be recycled. It was estimated that 127 and 165 g microbial protein were synthesized/kg organic matter truly digested in the rumen for low and high sulfur diets, respectively. A simple model using simultaneous equations was proposed to describe rumen sulfur metabolism.

  14. The global sulfur cycle

    NASA Technical Reports Server (NTRS)

    Sagan, D. (Editor)

    1985-01-01

    The results of the planetary biology microbial ecology's 1984 Summer Research Program, which examined various aspects of the global sulfur cycle are summarized. Ways in which sulfur flows through the many living and chemical species that inhabit the surface of the Earth were investigated. Major topics studied include: (1) sulfur cycling and metabolism of phototropic and filamentous sulfur bacteria; (2) sulfur reduction in sediments of marine and evaporite environments; (3) recent cyanobacterial mats; (4) microanalysis of community metabolism in proximity to the photic zone in potential stromatolites; and (5) formation and activity of microbial biofilms on metal sulfides and other mineral surfaces. Relationships between the global sulfur cycle and the understanding of the early evolution of the Earth and biosphere and current processes that affect global habitability are stressed.

  15. Mineral trioxide aggregate pulpotomy in autotransplanted immature mandibular third molar with a 4-year follow-up

    PubMed Central

    Dharmani, Umesh; Jadhav, Ganesh Ranganath; Kaur Dharmani, Charan Kamal; Devi, Takhellambam Premlata

    2016-01-01

    Autotransplantation is the surgical transposition of a tooth from its original site to another, replacing a lost or a compromised tooth by another tooth, usually the third molar in the same individual. This technique is considered a viable method due to its high success rate, well-grounded treatment option, provided the case selection and the procedure followed is within the acceptable limits. Autotransplantation is considered as an alternative approach of oral rehabilitations in a conservative manner mainly in young patients with compromised financial conditions to perform a high cost treatment. It is a fast way to recover function and aesthetic properties without interfering with the orofacial growth. This report describes a successful 4-year follow-up of a case of immediately performed mineral trioxide aggregate (MTA) pulpotomy in autotransplantated mandibular left immature third molar to replace the mandibular left first molar that was extracted due to extensive carious lesion. PMID:27217648

  16. Sulfur Tolerant Pd/Cu and Pd/Au Alloy Membranes for H2 Separation with High Pressure CO2 for Sequestration

    SciTech Connect

    Yi Hua Ma; Natalie Pomerantz; Chao-Huang Chen

    2008-09-30

    The effect of H{sub 2}S poisoning on Pd, Pd/Cu, and Pd/Au alloy composite membranes prepared by the electroless deposition method on porous Inconel supports was investigated to provide a fundamental understanding of the durability and preparation of sulfur tolerant membranes. X-ray photoelectron spectroscopy (XPS) studies showed that the exposure of pure Pd to 50 ppm H{sub 2}S/H{sub 2} mixtures caused bulk sulfide formation at lower temperatures and surface sulfide formation at higher temperatures. Lower temperatures, longer exposure times, and higher H{sub 2}S concentrations resulted in a higher degree of sulfidation. In a Pd membrane, the bulk sulfide formation caused a drastic irrecoverable H{sub 2} permeance decline and an irreparable loss in selectivity. Pd/Cu and Pd/Au alloy membranes exhibited permeance declines due to surface sulfide formation upon exposure to 50 ppm H{sub 2}S/H{sub 2} gas mixtures. However in contrast to the pure Pd membrane, the permeances of the Pd/Cu and Pd/Au alloy membranes were mostly recovered in pure H{sub 2} and the selectivity of the Pd alloy layers remained essentially intact throughout the characterization in H{sub 2}, He and H{sub 2}S/H{sub 2} mixtures which lasted several thousand hours. The amount of irreversible sulfur poisoning decreased with increasing temperature due to the exothermicity of H{sub 2}S adsorption. Longer exposure times increased the amount of irreversible poisoning of the Pd/Cu membrane but not the Pd/Au membrane. Pd/Au coupon studies of the galvanic displacement method showed that higher Au{sup 3+} concentrations, lower pH values, higher bath temperatures and stirring the bath at a rate of 200 rpm yielded faster displacement rates, more uniform depositions, and a higher Au content within the layers. While 400 C was found to be sufficient to form a Pd/Au alloy on the surface, high temperature X-ray diffraction (HTXRD) studies showed that even after annealing between 500-600 C, the Pd/Cu alloys could have

  17. High-resolution (SIMS) versus bulk sulfur isotope patterns of pyrite in Proterozoic microbialites with diverse mat textures

    NASA Astrophysics Data System (ADS)

    Gomes, M. L.; Fike, D. A.; Bergmann, K.; Knoll, A. H.

    2015-12-01

    Sulfur (S) isotope signatures of sedimentary pyrite preserved in marine rocks provide a rich suite of information about changes in biogeochemical cycling associated with the evolution of microbial metabolisms and oxygenation of Earth surface environments. Conventionally, these S isotope records are based on bulk rock measurements. Yet, in modern microbial mat environments, S isotope compositions of sulfide can vary by up to 40‰ over a spatial range of ~ 1 mm. Similar ranges of S isotope variability have been found in Archean pyrite grains using both Secondary Ion Mass Spectrometry and other micro-analytical techniques. These micron-scale patterns have been linked to changes in rates of microbial sulfate reduction and/or sulfide oxidation, isotopic distillation of the sulfate reservoir due to microbial sulfate reduction, and post-depositional alteration. Fine-scale mapping of S isotope compositions of pyrite can thus be used to differentiate primary environmental signals from post-depositional overprinting - improving our understanding of both. Here, we examine micron-scale S isotope patterns of pyrite in microbialites from the Mesoproterozoic-Neoproterozoic Sukhaya Tunguska Formation and Neoproterozoic Draken Formation in order to explore S isotope variability associated with different mat textures and pyrite grain morphologies. A primary goal is to link modern observations of how sulfide spatial isotope distributions reflect active microbial communities present at given depths in the mats to ancient processes driving fine-sale pyrite variability in microbialites. We find large (up to 60‰) S isotope variability within a spatial range of less than 2.5cm. The micron-scale S isotope measurements converge around the S isotope composition of pyrite extracted from bulk samples of the same microbialites. These micron-scale pyrite S isotope patterns have the potential to reveal important information about ancient biogeochemical cycling in Proterozoic mat environments

  18. Sulfur removal from coal

    SciTech Connect

    Lompa-Krzymien, L.

    1985-01-01

    Coal is treated to remove both pyritic and organic sulfur by contacting with an aqueous solution comprising cupric ions at temperatures of about 140/sup 0/ C.-200/sup 0/ C. under autogenic pressure, until substantial amounts of the sulfur are solubilized, separating the coal solids, and washing the solids with water to remove soluble forms of sulfur, iron and copper therefrom. The copper can be recovered and recycled as a cupric salt.

  19. Structural, electronic and magnetic properties of 3d metal trioxide clusters-doped monolayer graphene: A first-principles study

    NASA Astrophysics Data System (ADS)

    Rafique, Muhammad; Shuai, Yong; Tan, He-Ping; Hassan, Muhammad

    2017-03-01

    We present first-principles density-functional calculations for the structural, electronic and magnetic properties of monolayer graphene doped with 3d (Ti, V, Cr, Fe, Co, Mn and Ni) metal trioxide TMO3 halogen clusters. In this paper we used two approaches for 3d metal trioxide clusters (i) TMO3 halogen cluster was embedded in monolayer graphene substituting four carbon (C) atoms (ii) three C atoms were substituted by three oxygen (O) atoms in one graphene ring and TM atom was adsorbed at the hollow site of O atoms substituted graphene ring. All the impurities were tightly bonded in the graphene ring. In first case of TMO3 doped graphene layer, the bond length between Csbnd O atom was reduced and bond length between TM-O atom was increased. In case of Cr, Fe, Co and Ni atoms substitution in between the O atoms, leads to Fermi level shifting to conduction band thereby causing the Dirac cone to move into valence band, however a band gap appears at high symmetric K-point. In case of TiO3 and VO3 substitution, system exhibits semiconductor properties. Interestingly, TiO3-substituted system shows dilute magnetic semiconductor behavior with 2.00 μB magnetic moment. On the other hand, the substitution of CoO3, CrO3, FeO3 and MnO3 induced 1.015 μB, 2.347 μB, 2.084 μB and 3.584 μB magnetic moment, respectively. In second case of O atoms doped in graphene and TM atoms adsorbed at the hollow site, the O atom bulges out of graphene plane and bond length between TM-O atom is increased. After TM atoms adsorption at the O substituted graphene ring the Fermi level (EF) shifts into conduction band. In case of Cr and Ni adsorption, system displays indirect band gap semiconductor properties with 0.0 μB magnetic moment. Co adsorption exhibits dilute magnetic semiconductor behavior producing 0.916 μB magnetic moment. Fe, Mn, Ti and V adsorption introduces band gap at high symmetric K-point also inducing 1.54 μB, 0.9909 μB, 1.912 μB, and 0.98 μB magnetic moments, respectively

  20. Inverse Vulcanization of Sulfur using Natural Dienes as Sustainable Materials for Lithium-Sulfur Batteries.

    PubMed

    Gomez, Iñaki; Leonet, Olatz; Blazquez, J Alberto; Mecerreyes, David

    2016-12-20

    Lithium-sulfur batteries are among the most promising next-generation battery systems due to the high capacity of sulfur as cathodic material. Beyond its interesting intrinsic properties, sulfur possesses a very low conductivity and complex electrochemistry, which involves the high solubility of the lithium sulfides in the electrolyte. These two characteristics are at the core of a series of limitations of its performance as active cathode material, which leads to batteries with low cyclability. Recently, inverse vulcanized sulfur was shown to retain capacity far better than elemental sulfur, leading to batteries with excellent cyclability. Nevertheless, the diene co-monomers used so far in the inverse vulcanization process are man-made molecules. Herein, a tentative work on exploring inverse vulcanization using two naturally available monomers, diallyl sulfide and myrcene, is presented. The inverse vulcanization of sulfur was successfully completed, and the resulting polymers were characterized by FTIR, NMR spectroscopy, differential scanning calorimetry, and thermogravimetric analysis. Afterwards these polymers were tested as cathodic materials in lithium-sulfur cells. The sulfur-natural dienes materials exhibited high capacity at different C rates and high lifetime over 200 cycles with very high capacity retention at a moderate C rate of C/5. Altogether, these materials made from inexpensive and abundant chemicals are an excellent option as sustainable materials for electrochemical energy storage.

  1. The embryotoxic response to maternal chromium trioxide exposure in different strains of hamsters

    SciTech Connect

    Gale, T.F.

    1982-10-01

    This paper compares the chromium trioxide-induced embryotoxic effects among one noninbred (LVG) and five inbred (CB, LHC, LSH, MHA, PD4) strains of hamsters. A single dose of chromium trioxide (8 mg/kg, iv) was injected into pregnant hamsters on the morning of gestation Day 8. Treated and control animals were killed on gestation Day 15 and studied for the types and incidence of external and internal abnormalities, as well as the frequency of resorption sites per uterus. The embryotoxic effects described in this study include significant rates of resorptions, external abnormalities, cleft palate, and hydrocephalus. The results indicate that the MHA, LSH, and LVG strains are susceptible, while the CB, LHC, and PD4 strains are resistant to chromium trioxide-induced embryotoxicity. This study was compared with prior work in which the same hamster strains were treated with either cadmium, lead, or mercury.

  2. Pulpotomy of Symptomatic Permanent Teeth with Carious Exposure Using Mineral Trioxide Aggregate

    PubMed Central

    Barngkgei, Imad Hassan; Halboub, Esam Saleh; Alboni, Roula Safouh

    2013-01-01

    Introduction To evaluate the clinical and radiographic outcomes of pulpotomy treatment with mineral trioxide aggregate (MTA) in symptomatic mature permanent teeth with carious exposure. Materials and Methods Ten patients aged 27-54 years presented with 11 symptomatic permanent teeth (n=11). Each offending carious tooth was clinically and radiographically determined. We removed caries as conservatively as possible; however pulp exposure was inevitable. ProRoot MTA pulpotomy was performed on these teeth. The patients were followed-up clinically and radiographically for 24-42 months. Results Immediate relief of patients` symptoms occurred. Moreover, teeth responses to the electric pulp tester were within normal range on follow-up appointment and the radiographs did not reveal any abnormality/lesion in the periapical areas. Conclusion Pulpotomy using MTA could be a good alternative for root canal therapy (RCT) for managing symptomatic mature permanent teeth with carious exposure, however further large-scale multicenter clinical trials are highly encouraged to confirm this hypothesis. PMID:23717332

  3. Targeting catalase but not peroxiredoxins enhances arsenic trioxide-induced apoptosis in K562 cells.

    PubMed

    Song, Li-Li; Tu, Yao-Yao; Xia, Li; Wang, Wei-Wei; Wei, Wei; Ma, Chun-Min; Wen, Dong-Hua; Lei, Hu; Xu, Han-Zhang; Wu, Ying-Li

    2014-01-01

    Despite considerable efficacy of arsenic trioxide (As2O3) in acute promyelocytic leukemia (APL) treatment, other non-APL leukemias, such as chronic myeloid leukemia (CML), are less sensitive to As2O3 treatment. However, the underlying mechanism is not well understood. Here we show that relative As2O3-resistant K562 cells have significantly lower ROS levels than As2O3-sensitive NB4 cells. We compared the expression of several antioxidant enzymes in these two cell lines and found that peroxiredoxin 1/2/6 and catalase are expressed at high levels in K562 cells. We further investigated the possible role of peroxirdoxin 1/2/6 and catalase in determining the cellular sensitivity to As2O3. Interestingly, knockdown of peroxiredoxin 1/2/6 did not increase the susceptibility of K562 cells to As2O3. On the contrary, knockdown of catalase markedly enhanced As2O3-induced apoptosis. In addition, we provide evidence that overexpression of BCR/ABL cannot increase the expression of PRDX 1/2/6 and catalase. The current study reveals that the functional role of antioxidant enzymes is cellular context and treatment agents dependent; targeting catalase may represent a novel strategy to improve the efficacy of As2O3 in CML treatment.

  4. Properties of Hydrogen Sulfide Sensors Based on Thin Films of Tin Dioxide and Tungsten Trioxide

    NASA Astrophysics Data System (ADS)

    Sevastianov, E. Yu.; Maksimova, N. K.; Chernikov, E. V.; Sergeichenko, N. V.; Rudov, F. V.

    2016-12-01

    The effect of hydrogen sulfide in the concentration range of 0-100 ppm on the characteristics of thin films of tin dioxide and tungsten trioxide obtained by the methods of magnetron deposition and modified with gold in the bulk and on the surface is studied. The impurities of antimony and nickel have been additionally introduced into the SnO2 bulk. An optimal operating temperature of sensors 350°C was determined, at which there is a satisfactory correlation between the values of the response to H2S and the response time. Degradation of the sensor characteristics is investigated in the long-term ( 0.5-1.5 years) tests at operating temperature and periodic exposure to hydrogen sulfide, as well as after conservation of samples in the laboratory air. It is shown that for the fabrication of H2S sensors, the most promising are thin nanocrystalline Au/WO3:Au films characterized by a linear concentration dependence of the response and high stability of parameters during exploitation.

  5. Effects of EDTA on the hydration mechanism of mineral trioxide aggregate.

    PubMed

    Lee, Y-L; Lin, F-H; Wang, W-H; Ritchie, H H; Lan, W-H; Lin, C-P

    2007-06-01

    Ethylenediaminetetraacetic acid (EDTA) is commonly used during the preparation of obstructed root canals that face a high risk of root perforation. Such perforations may be repaired with mineral trioxide aggregate (MTA). Due to EDTA's ability to chelate calcium ions, we hypothesized that EDTA may disrupt the hydration of MTA. Using scanning electron microscopy and energy-dispersive x-ray spectroscopy, we found that MTA specimens stored in an EDTA solution had no crystalline structure and a Ca/Si molar ratio considerably lower than those obtained for specimens stored in distilled water and normal saline. Poor cell adhesion in EDTA-treated MTA was also noted. X-ray diffraction indicated that the peak corresponding to portlandite, which is normally present in hydrated MTA, was not shown in the EDTA group. The microhardness of EDTA-treated specimens was also significantly reduced (p < 0.0001). These findings suggest that EDTA interferes with the hydration of MTA, resulting in decreased hardness and poor biocompatibility.

  6. Bortezomib and Arsenic Trioxide Activity on a Myelodysplastic Cell Line (P39): A Gene Expression Study

    PubMed Central

    Savlı, Hakan; Galimberti, Sara; Sünnetçi, Deniz; Canestraro, Martina; Palumbo, Giuseppe; Nagy, Balint; Raimondo, Francesco Di; Petrini, Mario

    2015-01-01

    Objective: We aimed to understand the molecular pathways affected by bortezomib and arsenic trioxide treatment on myelomonocytoid cell line P39. Materials and Methods: Oligonucleotide microarray platforms were used for gene expression and pathway analysis. Confirmation studies were performed using quantitative real time PCR. Results: Bortezomib treatment has shown upregulated DIABLO and NF-κBIB (a NF-κB inhibitor) and downregulated NF-κB1, NF-κB2, and BIRC1 gene expressions. Combination treatment of the two compounds showed gene expression deregulations in concordance by the results of single bortezomib treatment. Especially, P53 was a pathway more significantly modified and a gene network centralized around the beta estradiol gene. Beta estradiol, BRCA2, and FOXA1 genes were remarkable deregulations in our findings. Conclusion: Results support the suggestions about possible use of proteasome inhibitors in the treatment of high-risk myelodysplastic syndrome (MDS). NF-κB was observed as an important modulator in leukemic transformation of MDS. PMID:25913414

  7. Electron Transfer Governed Crystal Transformation of Tungsten Trioxide upon Li Ions Intercalation

    SciTech Connect

    Wang, Zhiguo; He, Yang; Gu, Meng; Du, Yingge; Mao, Scott X.; Wang, Chongmin

    2016-09-21

    Reversible insertion/extraction of ions into a host lattice constitutes the fundamental operating principle of rechargeable battery and electrochromic materials. It is far more commonly observed that insertion of ions into a host lattice can lead to structural evolution of the host lattice, and for the most cases such a lattice evolution is subtle. However, it has never been clear as what kind of factors to control such a lattice structural evolution. Based on tungsten trioxide (WO3) model crystal, we use in situ transmission electron microscopy (TEM) and first principles calculation to explore the nature of Li ions intercalation induced crystal symmetry evolution of WO3. We discovered that Li insertion into the octahedral cavity of WO3 lattice will lead to a low to high symmetry transition, featuring a sequential monoclinic→tetragonal→cubic phase transition. The first principle calculation reveals that the phase transition is essentially governed by the electron transfer from Li to the WO6 octahedrons, which effectively leads to the weakening the W-O bond and modifying system band structure, resulting in an insulator to metal transition. The observation of the electronic effect on crystal symmetry and conductivity is significant, providing deep insights on the intercalation reactions in secondary rechargeable ion batteries and the approach for tailoring the functionalities of material based on insertion of ions in the lattice.

  8. Interaction between arsenic trioxide and human primary cells: emphasis on human cells of myeloid origin.

    PubMed

    Binet, François; Antoine, Francis; Girard, Denis

    2009-03-01

    Arsenic trioxide (As(2)O(3); ATO) is considered to be one of the most potent drugs in cancer chemotherapy and is highly effective in the treatment of acute promyelocytic leukemia (APL). It is well established that treatment of APL patients with ATO is associated with the disappearance of the PML-RARalpha fusion transcript, the characteristic APL gene product of the chromosomal translocation t(15;17). Although its mode of action is still not fully understood, ATO is known to induce cell apoptosis via generation of reactive oxygen species and activation of caspases. Several reports have indicated that ATO acts principally by inducing cell apoptosis not only in APL, but in a variety of non-APL cells including myeloma cells, chronic myeloid leukemia cells and cells of immune origin, including B or T lymphocytes, macrophages and, more recently, neutrophils. There is an increasing amount of data, including some from our laboratory, concerning the interaction between ATO and human primary cells. The focus of this review will be to cover the role of ATO in human immune primary cells with special emphasis on cells of myeloid origin.

  9. High-mobility and low-carrier-density sputtered MoS2 film formed by introducing residual sulfur during low-temperature in 3%-H2 annealing for three-dimensional ICs

    NASA Astrophysics Data System (ADS)

    Shimizu, Jun’ichi; Ohashi, Takumi; Matsuura, Kentaro; Muneta, Iriya; Kakushima, Kuniyuki; Tsutsui, Kazuo; Wakabayashi, Hitoshi

    2017-04-01

    We investigate the low-temperature formation of MoS2 films by radio frequency (RF) sputtering. This work is focused on reducing the number of sulfur defects and the improving electrical characteristics of sputtered MoS2 films by low-temperature annealing in various atmospheres. 10 nm MoS2 films were synthesized by the RF sputtering at 300 °C and followed by annealing in nitrogen or forming gas (FG: 3% hydrogen in N2) at 200–400 °C. As a result, the compensation for sulfur defects in FG anneal process using residual sulfur gave better results that in N2 annealing. Eventually, a high Hall-effect mobility of 36 cm2 V‑1 s‑1 and a low carrier density of 1014 cm‑3 were achieved.

  10. High-field 1H T1 and T2 NMR relaxation time measurements of H2O in homeopathic preparations of quartz, sulfur, and copper sulfate

    NASA Astrophysics Data System (ADS)

    Baumgartner, Stephan; Wolf, Martin; Skrabal, Peter; Bangerter, Felix; Heusser, Peter; Thurneysen, André; Wolf, Ursula

    2009-09-01

    Quantitative meta-analyses of randomized clinical trials investigating the specific therapeutic efficacy of homeopathic remedies yielded statistically significant differences compared to placebo. Since the remedies used contained mostly only very low concentrations of pharmacologically active compounds, these effects cannot be accounted for within the framework of current pharmacology. Theories to explain clinical effects of homeopathic remedies are partially based upon changes in diluent structure. To investigate the latter, we measured for the first time high-field (600/500 MHz) 1H T1 and T2 nuclear magnetic resonance relaxation times of H2O in homeopathic preparations with concurrent contamination control by inductively coupled plasma mass spectrometry (ICP-MS). Homeopathic preparations of quartz (10 c-30 c, n = 21, corresponding to iterative dilutions of 100-10-100-30), sulfur (13 x-30 x, n = 18, 10-13-10-30), and copper sulfate (11 c-30 c, n = 20, 100-11-100-30) were compared to n = 10 independent controls each (analogously agitated dilution medium) in randomized and blinded experiments. In none of the samples, the concentration of any element analyzed by ICP-MS exceeded 10 ppb. In the first measurement series (600 MHz), there was a significant increase in T1 for all samples as a function of time, and there were no significant differences between homeopathic potencies and controls. In the second measurement series (500 MHz) 1 year after preparation, we observed statistically significant increased T1 relaxation times for homeopathic sulfur preparations compared to controls. Fifteen out of 18 correlations between sample triplicates were higher for controls than for homeopathic preparations. No conclusive explanation for these phenomena can be given at present. Possible hypotheses involve differential leaching from the measurement vessel walls or a change in water molecule dynamics, i.e., in rotational correlation time and/or diffusion. Homeopathic preparations

  11. Solid-state C-13 and H-1 NMR imaging stdies of the accelerated-sulfur cured high vinyl polybutadiene. [NMR (nuclear magnetic resonance)

    SciTech Connect

    Rana, M.A.

    1993-01-01

    Solid-state [sup 13]C NMR and [sup 1]H Imaging methods have been used to follow the progress of accelerated-sulfur vulcanization of unfilled high vinyl polybutadiene. Different NMR pulse sequences have been used to characterize the micro-network structures present in the bulk of the finally cured rubber samples. These studies were made as a function of formulation and processing variables. The time-resolved, integrated rubber network. Mono-sulfidic as well as the residual accelerator fragments were differentiated from the polysulfidic crosslinks in a finally cured material. Dynamic studies of these network structures were made using spin-spin relaxation (T[sub 2c]) measurements. The activation energies calculated based on T[sub 2] were used to verify different carbons, directly attached to the sulfur atoms. A swelling method based on Flory-Rehner's equation was also used to determine the crosslink densities and the number-average molecular weight between the nodal junctions in different formulations. Different spatially resolved structural features have been detected in the swollen samples using NMR imaging method. The voids, no-voids and other impurities were differentiated on the basis of magnetic susceptibility differences. Cyclohexane was used as a swelling solvent to probe the morphological defects in these materials. The T[sub 2]-weighted images were used to evaluate the crosslink densities in different samples. The quantitative estimations based on histogram was also employed to determine the average volume per crosslink region. The contrast based on H-1 spin-density or mobility was highlighted in T[sub 2]-weighted images. The variations were found to be closely related to variation in both concentration and mobility of the network.

  12. Mesoporous hollow carbon spheres for lithium–sulfur batteries: distribution of sulfur and electrochemical performance

    PubMed Central

    Juhl, Anika C; Schneider, Artur; Ufer, Boris; Brezesinski, Torsten

    2016-01-01

    Summary Hollow carbon spheres (HCS) with a nanoporous shell are promising for the use in lithium–sulfur batteries because of the large internal void offering space for sulfur and polysulfide storage and confinement. However, there is an ongoing discussion whether the cavity is accessible for sulfur. Yet no valid proof of cavity filling has been presented, mostly due to application of unsuitable high-vacuum methods for the analysis of sulfur distribution. Here we describe the distribution of sulfur in hollow carbon spheres by powder X-ray diffraction and Raman spectroscopy along with results from scanning electron microscopy and nitrogen physisorption. The results of these methods lead to the conclusion that the cavity is not accessible for sulfur infiltration. Nevertheless, HCS/sulfur composite cathodes with areal sulfur loadings of 2.0 mg·cm−2 were investigated electrochemically, showing stable cycling performance with specific capacities of about 500 mAh·g−1 based on the mass of sulfur over 500 cycles. PMID:27826497

  13. Mesoporous hollow carbon spheres for lithium-sulfur batteries: distribution of sulfur and electrochemical performance.

    PubMed

    Juhl, Anika C; Schneider, Artur; Ufer, Boris; Brezesinski, Torsten; Janek, Jürgen; Fröba, Michael

    2016-01-01

    Hollow carbon spheres (HCS) with a nanoporous shell are promising for the use in lithium-sulfur batteries because of the large internal void offering space for sulfur and polysulfide storage and confinement. However, there is an ongoing discussion whether the cavity is accessible for sulfur. Yet no valid proof of cavity filling has been presented, mostly due to application of unsuitable high-vacuum methods for the analysis of sulfur distribution. Here we describe the distribution of sulfur in hollow carbon spheres by powder X-ray diffraction and Raman spectroscopy along with results from scanning electron microscopy and nitrogen physisorption. The results of these methods lead to the conclusion that the cavity is not accessible for sulfur infiltration. Nevertheless, HCS/sulfur composite cathodes with areal sulfur loadings of 2.0 mg·cm(-2) were investigated electrochemically, showing stable cycling performance with specific capacities of about 500 mAh·g(-1) based on the mass of sulfur over 500 cycles.

  14. Dual protection of sulfur by carbon nanospheres and graphene sheets for lithium-sulfur batteries.

    PubMed

    Wang, Bei; Wen, Yanfen; Ye, Delai; Yu, Hua; Sun, Bing; Wang, Guoxiu; Hulicova-Jurcakova, Denisa; Wang, Lianzhou

    2014-04-25

    Well-confined elemental sulfur was implanted into a stacked block of carbon nanospheres and graphene sheets through a simple solution process to create a new type of composite cathode material for lithium-sulfur batteries. Transmission electron microscopy and elemental mapping analysis confirm that the as-prepared composite material consists of graphene-wrapped carbon nanospheres with sulfur uniformly distributed in between, where the carbon nanospheres act as the sulfur carriers. With this structural design, the graphene contributes to direct coverage of sulfur to inhibit the mobility of polysulfides, whereas the carbon nanospheres undertake the role of carrying the sulfur into the carbon network. This composite achieves a high loading of sulfur (64.2 wt %) and gives a stable electrochemical performance with a maximum discharge capacity of 1394 mAh g(-1) at a current rate of 0.1 C as well as excellent rate capability at 1 C and 2 C. The improved electrochemical properties of this composite material are attributed to the dual functions of the carbon components, which effectively restrain the sulfur inside the carbon nano-network for use in lithium-sulfur rechargeable batteries.

  15. Missing SO2 oxidant in the coastal atmosphere? - Evidence from high resolution measurements of OH and atmospheric sulfur compounds

    NASA Astrophysics Data System (ADS)

    Berresheim, H.; Adam, M.; Monahan, C.; O'Dowd, C.; Plane, J. M. C.; Bohn, B.; Rohrer, F.

    2014-01-01

    Diurnal and seasonal variations of gaseous sulfuric acid (H2SO4) and methane sulfonic acid (MSA) were measured in N.E. Atlantic air at the Mace Head atmospheric research station during the years 2010 and 2011. The measurements utilized selected ion/chemical ionization mass spectrometry (SI/CIMS) with a detection limit for both compounds of 4.3 × 10 4 cm-3 at 5 min signal integration. The H2SO4 and MSA gas-phase concentrations were analysed in conjunction with the condensational sink for both compounds derived from 3 nm-10 μm (diameter) aerosol size distributions. Accommodation coefficients of 1.0 for H2SO4 and 0.12 for MSA were assumed leading to estimated atmospheric lifetimes of the order of 7 min and 25 min, respectively. With the SI/CIMS instrument in OH measurement mode alternating between OH signal and background (non-OH) signal evidence was obtained for the presence of one or more unknown oxidants of SO2 in addition to OH. Depending on the nature of the oxidant(s) their ambient concentration may be enhanced in the CIMS inlet system by additional production. The apparent unknown SO2 oxidant was additionally confirmed by direct measurements of SO2 in conjunction with calculated H2SO4 concentrations. The calculated concentrations were consistently lower than the measured concentrations by a factor 4.8 ± 3.4 when considering the oxidation of SO2 by OH as the only source of H2SO4. Both the OH and the background signal were also observed to increase significantly during daytime aerosol nucleation events, independent of the ozone photolysis frequency, J(O1D), and were followed by peaks in both H2SO4 and MSA concentrations. This suggests a strong relation between the unknown oxidant(s), OH chemistry, and the atmospheric photo-oxidation of biogenic iodine compounds. As to the identity of the oxidant(s), we have been able to exclude ClO, BrO, IO, and OIO as possible candidates based on ab initio calculations. Stabilized Criegee intermediates (sCI) produced from