WorldWideScience

Sample records for internal carbon sulfur

  1. Mesoporous hollow carbon spheres for lithium–sulfur batteries: distribution of sulfur and electrochemical performance

    Directory of Open Access Journals (Sweden)

    Anika C. Juhl

    2016-08-01

    Full Text Available 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.

  2. Sulfur-impregnated disordered carbon nanotubes cathode for lithium-sulfur batteries.

    Science.gov (United States)

    Guo, Juchen; Xu, Yunhua; Wang, Chunsheng

    2011-10-12

    The commercialization of lithium-sulfur batteries is hindered by low cycle stability and low efficiency, which are induced by sulfur active material loss and polysulfide shuttle reaction through dissolution into electrolyte. In this study, sulfur-impregnated disordered carbon nanotubes are synthesized as cathode material for the lithium-sulfur battery. The obtained sulfur-carbon tube cathodes demonstrate superior cyclability and Coulombic efficiency. More importantly, the electrochemical characterization indicates a new stabilization mechanism of sulfur in carbon induced by heat treatment.

  3. Ordered mesoporous carbon/sulfur nanocomposite of high performances as cathode for lithium-sulfur battery

    Energy Technology Data Exchange (ETDEWEB)

    Chen Shuru [State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemistry, College of Chemistry and Chemical Engineering, School of Energy Research, Xiamen University, Xiamen 361005 (China); Zhai Yunpu [Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, and Advanced Materials Laboratory, Fudan University, Shanghai 200433 (China); Xu Guiliang; Jiang Yanxia [State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemistry, College of Chemistry and Chemical Engineering, School of Energy Research, Xiamen University, Xiamen 361005 (China); Zhao Dongyuan, E-mail: dyzhao@fudan.edu.cn [Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, and Advanced Materials Laboratory, Fudan University, Shanghai 200433 (China); Li Juntao; Huang Ling [State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemistry, College of Chemistry and Chemical Engineering, School of Energy Research, Xiamen University, Xiamen 361005 (China); Sun Shigang, E-mail: sgsun@xmu.edu.cn [State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemistry, College of Chemistry and Chemical Engineering, School of Energy Research, Xiamen University, Xiamen 361005 (China)

    2011-11-01

    Ordered mesoporous carbon/sulfur (OMC/S) nanocomposites with hierarchically structured sulfur loading, ranging from 50 to 75 wt%, were synthesized via a simple melt-diffusion strategy. The OMC with a BET surface area of 2102 m{sup 2} g{sup -1}, a pore volume of 2.0 cm{sup 3} g{sup -1} and unique bimodal mesoporous (5.6/2.3 nm) structure, was prepared from a triconstituent co-assembly method. The resulting OMC/S nanocomposite material served as cathode of rechargeable lithium-sulfur (Li-S) battery. It has been tested that the novel OMC/S cathode can deliver a superior reversible capacity and cyclability. In particular, the nanocomposite with a loading of 60 wt% sulfur (OMC/S-60) presents the highest sulfur utilization ca. 70%, an excellent high rate capability ca. 6 C and a good cycling stability for up to 400 full charge-discharge cycles. The exceptional electrochemical performances are exclusively attributed to the large internal surface area and high porosity of the ordered mesoporous carbon, which favorites both electron and Li-ion transportations.

  4. Incorporating Sulfur Inside the Pores of Carbons for Advanced Lithium-Sulfur Batteries: An Electrolysis Approach.

    Science.gov (United States)

    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.

  5. Sulfur-carbon nanocomposites and their application as cathode materials in lithium-sulfur batteries

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Chengdu; Dudney, Nancy J.; Howe, Jane Y.

    2017-08-01

    The invention is directed in a first aspect to a sulfur-carbon composite material comprising: (i) a bimodal porous carbon component containing therein a first mode of pores which are mesopores, and a second mode of pores which are micropores; and (ii) elemental sulfur contained in at least a portion of said micropores. The invention is also directed to the aforesaid sulfur-carbon composite as a layer on a current collector material; a lithium ion battery containing the sulfur-carbon composite in a cathode therein; as well as a method for preparing the sulfur-composite material.

  6. Dual protection of sulfur by carbon nanospheres and graphene sheets for lithium-sulfur batteries.

    Science.gov (United States)

    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.

  7. A Carbon-Sulfur Hybrid with Pomegranate-like Structure for Lithium-Sulfur Batteries.

    Science.gov (United States)

    Shi, Yanting; Lv, Wei; Niu, Shuzhang; He, Yanbing; Zhou, Guangmin; Chen, Guohua; Li, Baohua; Yang, Quan-Hong; Kang, Feiyu

    2016-05-01

    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.

  8. Sulfur(IV)-mediated carbon-carbon bond formation

    OpenAIRE

    Dean, William Michael

    2016-01-01

    This thesis details the development of methods for and application of the synthesis of carbon carbon bonds using organic sulfur(IV) chemistry. More specifically, the formation of C(sp2) C(sp3) and C(sp3) C(sp3) bonds is explored in detail. The necessity for this research stems from a correlation between a high proportion of sp3 centres in drug candidates, and their success in clinical trials. By facilitating the synthesis of drug candidates with higher fractions of sp3 hybridised carbon atoms...

  9. Sulfurized activated carbon for high energy density supercapacitors

    Science.gov (United States)

    Huang, Yunxia; Candelaria, Stephanie L.; Li, Yanwei; Li, Zhimin; Tian, Jianjun; Zhang, Lili; Cao, Guozhong

    2014-04-01

    Sulfurized activated carbon (SAC), made by coating the pore surface with thiophenic sulfur functional groups from the pyrolysis of sulfur flakes, were characterized and tested for supercapacitor applications. From X-ray photoelectron spectroscopy (XPS), the sulfur content in the SAC was found to be 2.7 at%. Electrochemical properties from potentiostatic and galvanostatic measurements, and electrochemical impedance spectroscopy (EIS) were used to evaluate the effect of sulfur on porous carbon electrodes. The SAC electrode exhibits better conductivity, and an obvious increase in specific capacitance that is almost 40% higher than plain activated carbons (ACs) electrode at a high current density of 1.4 A g-1. The proposed mechanism for improved conductivity and capacitive performance due to the sulfur functional groups on ACs will be discussed.

  10. Impact of sulfur oxides on mercury capture by activated carbon.

    Science.gov (United States)

    Presto, Albert A; Granite, Evan J

    2007-09-15

    Recent field tests of mercury removal with activated carbon injection (ACI) have revealed that mercury capture is limited in flue gases containing high concentrations of sulfur oxides (SOx). In order to gain a more complete understanding of the impact of SOx on ACl, mercury capture was tested under varying conditions of SO2 and SO3 concentrations using a packed bed reactor and simulated flue gas (SFG). The final mercury content of the activated carbons is independent of the SO2 concentration in the SFG, but the presence of SO3 inhibits mercury capture even at the lowest concentration tested (20 ppm). The mercury removal capacity decreases as the sulfur content of the used activated carbons increases from 1 to 10%. In one extreme case, an activated carbon with 10% sulfur, prepared by H2SO4 impregnation, shows almost no mercury capacity. The results suggest that mercury and sulfur oxides are in competition for the same binding sites on the carbon surface.

  11. Reduction of Sulfur Dioxide on Carbons Catalyzed by Salts

    Directory of Open Access Journals (Sweden)

    Wido Schreiner

    2005-01-01

    Full Text Available Abstract. The reduction of SO2 on different carbons in the presence of the nitrates and sulfides of sodium, potassium and calcium and potassium polysulfides was studied. The presence of salts increased the initial rate 2-5 fold for all of them and did not change the product distribution. The catalysis was not determined by the cation and there was no difference in the catalytic reactivity between nitrates and sulfides. The sulfur content of the activated carbon increased during the reaction on account of the stable reactive intermediates in the reduction of SO2. In the presence of NaNO3 or Na2S, the amount of sulfur incorporated was in the molar ratio Na:S = 3 ± 0.3, and the XPS spectra of the residual carbon showed an increase of ca. 9% of the non-oxidized form of sulfur in the intermediates. In the absence of salt, it is proposed that after the adsorption of SO2 on the carbon, a 1,3,2-dioxathiolane or 1,2-oxathietene 2-oxide are formed and that decompose to produce CO2 and atomic sulfur. The non-oxidized sulfur intermediate would be an episulfide 3, formed from the reaction of the atomic sulfur with the nearest double bond and followed by consecutive reactions of insertion of atomic sulfur to form a trisulfide. Extrusion of S2 from the trisulfide would regenerate the episulfide, establishing a sulfidedisulfide-trisulfide equilibrium that worked as a capture-release cycle of sulfur. In the presence of salt, the results are consistent with the assumption that the episulfide 3 reacts with the corresponding sulfide anion to form a disulfide anion, which upon reaction with atomic sulfur forms a trisulfide anion that decomposes releasing diatomic sulfur S2, transporting the sulfur and generating a thiolate that is part of the catalytic cycle.

  12. Biogeochemical Cycles of Carbon and Sulfur

    Science.gov (United States)

    DesMarais, David J.; DeVincenzi, D. (Technical Monitor)

    2002-01-01

    The elements carbon (C) and sulfur (S) interact with each other across a network of elemental reservoirs that are interconnected by an array of physical, chemical and biological processes. These networks are termed the biogeochemical C and S cycles. The compounds of C are highly important, not only as organic matter, but also as atmospheric greenhouse gases, pH buffers in seawater, oxidation-reduction buffers virtually everywhere, and key magmatic constituents affecting plutonism and volcanism. The element S assumes important roles as an oxidation-reduction partner with C and Fe in biological systems, as a key constituent in magmas and volcanic gases, and as a major influence upon pH in certain environments. This presentation describes the modern biogeochemical C and S cycles. Measurements are described whereby stable isotopes can help to infer the nature and quantitative significance of biological and geological processes involved in the C and S cycles. This lecture also summarizes the geological and climatologic aspects of the ancient C and S cycles, as well as the planetary and extraterrestrial processes that influenced their evolution over millions to billions of years.

  13. Biogeochemical Cycles of Carbon and Sulfur

    Science.gov (United States)

    DesMarais, David J.; DeVincenzi, D. (Technical Monitor)

    2002-01-01

    The elements carbon (C) and sulfur (S) interact with each other across a network of elemental reservoirs that are interconnected by an array of physical, chemical and biological processes. These networks are termed the biogeochemical C and S cycles. The compounds of C are highly important, not only as organic matter, but also as atmospheric greenhouse gases, pH buffers in seawater, oxidation-reduction buffers virtually everywhere, and key magmatic constituents affecting plutonism and volcanism. The element S assumes important roles as an oxidation-reduction partner with C and Fe in biological systems, as a key constituent in magmas and volcanic gases, and as a major influence upon pH in certain environments. This presentation describes the modern biogeochemical C and S cycles. Measurements are described whereby stable isotopes can help to infer the nature and quantitative significance of biological and geological processes involved in the C and S cycles. This lecture also summarizes the geological and climatologic aspects of the ancient C and S cycles, as well as the planetary and extraterrestrial processes that influenced their evolution over millions to billions of years.

  14. Tailoring Pore Size of Nitrogen-Doped Hollow Carbon Nanospheres for Confi ning Sulfur in Lithium–Sulfur Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Weidong [General Motors Global Research and Development Center, Warren, MI (United States); Wang, Chong M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Zhang, Quiglin [General Motors Global Research and Development Center, Warren, MI (United States); Abruna, Hector D. [Cornell Univ., Ithaca, NY (United States); He, Yang [Univ. of Pittsburgh, PA (United States); Wang, Jiangwei [Univ. of Pittsburgh, PA (United States); Mao, Scott X. [Univ. of Pittsburgh, PA (United States); Xiao, Xingcheng [General Motors Global Research and Development Center, Warren, MI (United States)

    2015-08-19

    Three types of nitrogen-doped hollow carbon spheres with different pore sized porous shells are prepared to investigate the performance of sulfur confinement. The reason that why no sulfur is observed in previous research is determined and it is successfully demonstrated that the sulfur/polysulfide will overflow the porous carbon during the lithiation process.

  15. Core-shell meso/microporous carbon host for sulfur loading toward applications in lithium-sulfur batteries

    Institute of Scientific and Technical Information of China (English)

    Juan Zhang; Huan Ye; Yaxia Yin; Yuguo Guo

    2014-01-01

    Lithium-sulfur (Li-S) batteries belong to one of the promising technologies for high-energy-density rechargeable batteries. However, sulfur cathodes suffer from inherent problems of its poor electronic conductivity and the shuttling of highly dissoluble lithium polysulfides generated during the cycles. Loading sulfur into porous carbons has been proved to be an effective approach to alleviate these issues. Mesoporous and microporous carbons have been widely used for sulfur accommodation, but mesoporous carbons have poor sulfur confinement, whereas microporous carbons are impeded by low sulfur loading rates. Here, a core-shell carbon, combining both the merits of mesoporous carbon with large pore volume and microporous carbon with effective sulfur confinement, was prepared by coating the mesoporous CMK-3 with a microporous carbon (MPC) shell and served as the carbon host (CMK-3@MPC) to accommodate sulfur. After sulfur infusion, the as-obtained S/(CMK-3@MPC) cathode delivered a high initial capacity of up to 1422 mAh·g-1 and sustained 654 mAh·g-1 reversible specific capacity after 36 cycles at 0.1 C. The good performance is ascribed to the unique core-shell structure of the CMK-3@MPC matrix, in which sulfur can be effectively confined within the meso/microporous carbon host, thus achieving simultaneously high electrochemical utilization.

  16. Global geochemical cycles of carbon, sulfur and oxygen

    Science.gov (United States)

    Walker, J. C.

    1986-01-01

    Time resolved data on the carbon isotopic composition of carbonate minerals and the sulfur isotopic composition or sulfate minerals show a strong negative correlation during the Cretaceous. Carbonate minerals are isotopically heavy during this period while sulfate minerals are isotopically light. The implication is that carbon is being transferred from the oxidized, carbonate reservoir to the reservoir of isotopically light reduced organic carbon in sedimentary rocks while sulfur is being transferred from the reservoir of isotopically light sedimentary sulfide to the oxidized, sulfate reservoir. These apparently oppositely directed changes in the oxidation state of average sedimentary carbon and sulfur are surprising because of a well-established and easy to understand correlation between the concentrations of reduced organic carbon and sulfide minerals in sedimentary rocks. Rocks rich in reduced carbon are also rich in reduced sulfur. The isotopic and concentration data can be reconciled by a model which invokes a significant flux of hydrothermal sulfide to the deep sea, at least during the Cretaceous.

  17. Distribution of Sulfur in Carbon/Sulfur Nanocomposites Analyzed by Small-Angle X-ray Scattering.

    Science.gov (United States)

    Petzold, Albrecht; Juhl, Anika; Scholz, Jonas; Ufer, Boris; Goerigk, Günter; Fröba, Michael; Ballauff, Matthias; Mascotto, Simone

    2016-03-22

    The analysis of sulfur distribution in porous carbon/sulfur nanocomposites using small-angle X-ray scattering (SAXS) is presented. Ordered porous CMK-8 carbon was used as the host matrix and gradually filled with sulfur (20-50 wt %) via melt impregnation. Owing to the almost complete match between the electron densities of carbon and sulfur, the porous nanocomposites present in essence a two-phase system and the filling of the host material can be precisely followed by this method. The absolute scattering intensities normalized per unit of mass were corrected accounting for the scattering contribution of the turbostratic microstructure of carbon and amorphous sulfur. The analysis using the Porod parameter and the chord-length distribution (CLD) approach determined the specific surface areas and filling mechanism of the nanocomposite materials, respectively. Thus, SAXS provides comprehensive characterization of the sulfur distribution in porous carbon and valuable information for a deeper understanding of cathode materials of lithium-sulfur batteries.

  18. Nitrogen--sulfur--carbon nanocomposites and their application as cathode materials in lithium--sulfur batteries

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Sheng; Sun, Xiao-Guang; Guo, Bingkun; Wang, Xiqing; Mayes, Richard T.; Ben, Teng; Qiu, Shilun

    2016-09-27

    The invention is directed in a first aspect to electron-conducting porous compositions comprising an organic polymer matrix doped with nitrogen atoms and having elemental sulfur dispersed therein, particularly such compositions having an ordered framework structure. The invention is also directed to composites of such S/N-doped electron-conducting porous aromatic framework (PAF) compositions, or composites of an S/N-doped mesoporous carbon composition, which includes the S/N-doped composition in admixture with a binder, and optionally, conductive carbon. The invention is further directed to cathodes for a lithium-sulfur battery in which such composites are incorporated.

  19. Effect of sulfur content in a sulfur-activated carbon composite on the electrochemical properties of a lithium/sulfur battery

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jin-Woo; Kim, Changhyeon; Ryu, Ho-Suk; Cho, Gyu-Bong; Cho, Kwon-Koo; Kim, Ki-Won [School of Materials Science and Engineering, Gyeongsang National University, Jinju (Korea, Republic of); Ahn, Jou-Hyeon [Department of Chemical & Biological Engineering, Gyeongsang National University, Jinju (Korea, Republic of); Wang, Guoxiu [School of Chemistry and Forensic Science, University of Technology Sydney, Sydney, NSW 2007 (Australia); Ahn, Jae-Pyeung [Advanced Analysis Center, Research Planning & Coordination Division, KIST, Seoul (Korea, Republic of); Ahn, Hyo-Jun, E-mail: ahj@gnu.ac.kr [School of Materials Science and Engineering, Gyeongsang National University, Jinju (Korea, Republic of)

    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)

  20. A composite of hollow carbon nanospheres and sulfur-rich polymers for lithium-sulfur batteries

    Science.gov (United States)

    Zeng, Shao-Zhong; Yao, Yuechao; Zeng, Xierong; He, Qianjun; Zheng, Xianfeng; Chen, Shuangshuang; Tu, Wenxuan; Zou, Jizhao

    2017-07-01

    Lithium-sulfur batteries are the most promising candidates for future high-energy applications because of the unparalleled capacity of sulfur (1675 mAh g-1). However, lithium-sulfur batteries have limited cycle life and rate capability due to the dissolution of polysulfides and the extremely low electronic conductivity of sulfur. To solve these issues, various porous carbons including hollow carbon nanospheres (HCNs) have been used for improving the conductivity. However, these methods still suffer from polysulfides dissolution/loss owing to their weak physical adsorption to polysulfides. Herein, we introduced a covalent grafting route to composite the HCNs and the vulcanized trithiocyanuric acid (TTCA). The composite exhibits a high loading of the vulcanized TTCA by the HCNs with high surface area and large pore volume, and covalent bonds to sulfur, effectively depressing the dissolution of polysulfides. The first discharge capacity of the composite reaches 1430 mAh g-1 at 0.1 C and 1227 mAh g-1 at 0.2 C.

  1. ELEMENTAL MERCURY ADSORPTION BY ACTIVATED CARBON TREATED WITH SULFURIC ACID

    Science.gov (United States)

    The paper gives results of a study of the adsorption of elemental mercury at 125 C by a sulfuric-acid (H2S04, 50% w/w/ solution)-treated carbon for the removal of mercury from flue gas. The pore structure of the sample was characterized by nitrogen (N2) at -196 C and the t-plot m...

  2. Reduction of Sulfur Dioxide on Carbons Catalyzed by Salts

    OpenAIRE

    2005-01-01

    Abstract. The reduction of SO2 on different carbons in the presence of the nitrates and sulfides of sodium, potassium and calcium and potassium polysulfides was studied. The presence of salts increased the initial rate 2-5 fold for all of them and did not change the product distribution. The catalysis was not determined by the cation and there was no difference in the catalytic reactivity between nitrates and sulfides. The sulfur content of the activated carbon increased during the reaction o...

  3. Multiwalled carbon nanotubes-sulfur composites with enhanced electrochemical performance for lithium/sulfur batteries

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Xin Zhou; Jin, Bo, E-mail: jinbo@jlu.edu.cn; Xin, Pei Ming; Wang, Huan Huan

    2014-07-01

    Multiwalled carbon nanotubes-sulfur (MWCNTs-S) composites were synthesized by chemical activation of MWCNTs and capillarity between sulfur and MWCNTs. The MWCNTs activated by potassium hydroxide (denoted as K-MWCNTs) were used as conductive additive. The as-prepared K-MWCNTs-S composites can display excellent cycle stability and rate capability with the initial discharge capacity of 741 mAh g⁻¹ and capacity retention of 80% after 50 cycles compared to pure S. The improvement in the electrochemical performance for K-MWCNTs-S composites is attributed to the interstitial structure of the MWCNTs resulted from the strong chemical etching, which can facilitate the insertion and extraction of Li ions and more better percolation of the electrolyte, and also ascribed to enhanced electronic conductivity of K-MWCNTs-S composites. It is indicated that the K-MWCNTs-S composites can be used as the cathode materials for lithium–sulfur batteries.

  4. Biotic and abiotic carbon to sulfur bond cleavage. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Frost, J.W.

    1994-05-01

    The microbial desulfurization of organosulfur compounds occurs by unprecedented and largely unexplored biochemical processes. A study of such biotic desulfurizations can be expected to give rise to new and useful chemistry and enzymology. The potential value of understanding and harnessing these processes is seen in relation to the need for methods for the removal of organically bound sulfur from coal and the degradation of organic sulfur-containing pollutants. This research effort has been directed towards an examination of desulfurization ability in well characterized microorganisms, the isolation of bacteria with desulfurization ability from natural sources, the characterization and mechanistic evaluation of the observed biocatalytic processes, the development of biomimetic synthetic organic chemistry based on biotic desulfurization mechanisms and the design and preparation of improved coal model compounds for use in microbial selection processes. A systematic approach to studying biodesulfurizations was undertaken in which organosulfur compounds have been broken down into classes based on the oxidation state of the sulfur atom and the structure of the rest of the organic material. Microbes have been evaluated in terms of ability to degrade organosulfur compounds with sulfur in its sulfonic acid oxidation state. These compounds are likely intermediates in coal desulfurization and are present in the environment as persistent pollutants in the form of detergents. It is known that oxygen bonded to sulfur lowers the carbon-sulfur bond energy, providing a thermodynamic basis for starting with this class of compounds.

  5. Nitrogen, carbon, and sulfur metabolism in natural Thioploca samples

    DEFF Research Database (Denmark)

    Otte, S.; Kuenen, JG; Nielsen, LP

    1999-01-01

    Filamentous sulfur bacteria of the genus Thioploca occur as dense mats on the continental shelf off the coast of Chile and Peru. Since little is known about their nitrogen, sulfur, and carbon metabolism, this study was undertaken to investigate their (eco)physiology. Thioploca is able to store......]acetate incorporation was 0.4 nmol min(-1) mg of protein(-1), which is equal to the CO(2) fixation rate, and no (14)CO(2) production was detected. These results suggest that Thioploca species are facultative chemolithoautotrophs capable of mixotrophic growth. Microautoradiography confirmed that Thioploca cells...

  6. Selective catalytic reduction of sulfur dioxide by carbon monoxide over iron oxide supported on activated carbon

    OpenAIRE

    2014-01-01

    The selective reduction of sulfur dioxide with carbon monoxide to elemental sulfur was studied over AC-supported transition-metal oxide catalysts. According to the study, Fe2O3/AC was the most active catalyst among the 4 AC-supported catalysts tested. By using Fe2O3/AC, the best catalyst, when the feed conditions were properly optimized (CO/SO2 molar ratio = 2:1; sulfidation temperature, 400 °C; Fe content, 20 wt%; GHSV = 7000 mL g-1 h-1), 95.43% sulfur dioxide conversion and 86.59% sulfur yi...

  7. Doped carbon-sulfur species nanocomposite cathode for Li--S batteries

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Donghai; Xu, Tianren; Song, Jiangxuan

    2015-12-29

    We report a heteroatom-doped carbon framework that acts both as conductive network and polysulfide immobilizer for lithium-sulfur cathodes. The doped carbon forms chemical bonding with elemental sulfur and/or sulfur compound. This can significantly inhibit the diffusion of lithium polysulfides in the electrolyte, leading to high capacity retention and high coulombic efficiency.

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

    Directory of Open Access Journals (Sweden)

    Kangke Jin

    2015-09-01

    Full Text Available 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.

  9. Simultaneous activation/sulfurization method for production of sulfurized activated carbons: characterization and Hg(II) adsorption capacity.

    Science.gov (United States)

    Shamsijazeyi, Hadi; Kaghazchi, Tahereh

    2014-01-01

    As an inexpensive method for modification of activated carbons (ACs), sulfurization has attracted significant attention. However, the resulting sulfurized activated carbons (SACs) often are less porous than the original ACs. In this work, we propose a new method for concurrent sulfurization/activation that can lead to preparation of SACs with more porosity than the corresponding non-sulfurized ACs. By using scanning electron microscopy, nitrogen adsorption/desorption, and iodine number experiments, the porous structure of the SACs has been compared with that of non-sulfurized ACs. The specific surface areas of SACs are higher than the corresponding ACs, regardless of the type of activation agents used. For instance, the specific surface area of SAC and AC activated with phosphoric acid is 1,637 and 1,338 m(2)/g, respectively. Additionally, sulfur contents and surface charges (pHpzc) of the SACs and non-sulfurized ACs are compared. In fact, the SACs have higher sulfur contents and more acidic surfaces. Furthermore, the Hg(II) adsorption capacity of SACs has been compared with the corresponding non-sulfurized ACs. The Hg(II) adsorption isotherms on a selected SAC is measured at different pH values and temperatures. Hg(II) adsorptions as high as 293 mg/g are observed by using SACs prepared by the method proposed in this study.

  10. Stable carbon, nitrogen and sulfur isotopes in non-carbonate fractions of cold-seep carbonates

    Science.gov (United States)

    Feng, Dong; Peng, Yongbo; Peckmann, Jörn; Roberts, Harry; Chen, Duofu

    2017-04-01

    Sulfate-driven anaerobic oxidation of methane (AOM) supports chemosynthesis-based communities and limits the release of methane from marine sediments. This process promotes the formation of carbonates close to the seafloor along continental margins. The geochemical characteristics of the carbonate minerals of these rocks are increasingly understood, questions remain about the geochemical characteristics of the non-carbonate fractions. Here, we report stable carbon, nitrogen and sulfur isotope patterns in non-carbonate fractions of seep carbonates. The authigenic carbonates were collected from three modern seep provinces (Black Sea, Gulf of Mexico, and South China Sea) and three ancient seep deposits (Marmorito, northern Italy, Miocene; SR4 deposit of the Lincoln Creek Formation and Whiskey Creek, western Washington, USA, Eocene to Oligocene). The δ13C values of non-carbonate fractions range from ˜-25‰ to -80‰ VPDB. These values indicate that fossil methane mixed with varying amounts of pelagic organic matter is the dominant source of carbon in these fractions. The relatively small offset between the δ34S signatures of the non-carbonate fractions and the respective sulfide minerals suggests that locally produced hydrogen sulfide is the main source of sulfur in seep environments. The δ15N values of the non-carbonate fractions are generally lower than the corresponding values of deep-sea sediments, suggesting that organic nitrogen is mostly of a local origin. This study reveals the potential of using δ13C, δ15N, δ34S values to discern seep and non-seep deposits. In cases where δ13Ccarbonate values are only moderately low due to mixing processes and lipid biomarkers have been erased in the course of burial, it is difficult to trace back AOM owing to the lack of other records. This problem is even more pronounced when authigenic carbonate is not available in ancient seep environments. Acknowledgments: The authors thank BOEM and NOAA for their years' support

  11. Enhanced mercuric chloride adsorption onto sulfur-modified activated carbons derived from waste tires.

    Science.gov (United States)

    Yuan, Chung-Shin; Wang, Guangzhi; Xue, Sheng-Han; Ie, Iau-Ren; Jen, Yi-Hsiu; Tsai, Hsieh-Hung; Chen, Wei-Jin

    2012-07-01

    A number of activated carbons derived from waste tires were further impregnated by gaseous elemental sulfur at temperatures of 400 and 650 degrees C, with a carbon and sulfur mass ratio of 1:3. The capabilities of sulfur diffusing into the micropores of the activated carbons were significantly different between 400 and 650 degrees C, resulting in obvious dissimilarities in the sulfur content of the activated carbons. The sulfur-impregnated activated carbons were examined for the adsorptive capacity of gas-phase mercuric chloride (HgC1) by thermogravimetric analysis (TGA). The analytical precision of TGA was up to 10(-6) g at the inlet HgCl2 concentrations of 100, 300, and 500 microg/m3, for an adsorption time of 3 hr and an adsorption temperature of 150 degrees C, simulating the flue gas emitted from municipal solid waste (MSW) incinerators. Experimental results showed that sulfur modification can slightly reduce the specific surface area of activated carbons. High-surface-area activated carbons after sulfur modification had abundant mesopores and micropores, whereas low-surface-area activated carbons had abundant macropores and mesopores. Sulfur molecules were evenly distributed on the surface of the inner pores after sulfur modification, and the sulfur content of the activated carbons increased from 2-2.5% to 5-11%. After sulfur modification, the adsorptive capacity of HgCl2 for high-surface-area sulfurized activated carbons reached 1.557 mg/g (22 times higher than the virgin activated carbons). The injection of activated carbons was followed by fabric filtration, which is commonly used to remove HgCl2 from MSW incinerators. The residence time of activated carbons collected in the fabric filter is commonly about 1 hr, but the time required to achieve equilibrium is less than 10 min. Consequently, it is worthwhile to compare the adsorption rates of HgCl2 in the time intervals of < 10 and 10-60 min.

  12. Hollow spherical carbonized polypyrrole/sulfur composite cathode materials for lithium/sulfur cells with long cycle life

    Science.gov (United States)

    Wang, Zhongbao; Zhang, Shichao; Zhang, Lan; Lin, Ruoxu; Wu, Xiaomeng; Fang, Hua; Ren, Yanbiao

    2014-02-01

    Hollow carbonized polypyrrole (PPy) spheres are synthesized using poly(methyl methacrylate-ethyl acrylate-acrylic acid) latex spheres as sacrificial templates. The hollow spherical carbonized PPy/sulfur composite cathode materials are prepared by heating the mixture of hollow carbonized PPy spheres and element sulfur at 155 °C for 24 h. Scanning electron microscope (SEM) and transmission electron microscope (TEM) observations show the hollow structures of the carbonized PPy spheres and the homogeneous distribution of sulfur on the carbonized PPy shells. The hollow spherical carbonized PPy/sulfur composite with 60.9 wt.% S shows high specific capacity and excellent cycling stability when used as the cathode materials in lithium/sulfur cells, whose initial specific discharge capacity reaches as high as 1320 mA h g-1 and the reversible discharge capacity retains 758 mA h g-1 after 400 cycles at 0.2C. The excellent electrochemical properties benefit from the hollow structures and the flexible shells of the carbonized PPy spheres.

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

    Science.gov (United States)

    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 sulfur host based on titanium monoxide@carbon hollow spheres for advanced lithium-sulfur batteries

    Science.gov (United States)

    Li, Zhen; Zhang, Jintao; Guan, Buyuan; Wang, Da; Liu, Li-Min; Lou, Xiong Wen (David)

    2016-10-01

    Lithium-sulfur batteries show advantages for next-generation electrical energy storage due to their high energy density and cost effectiveness. Enhancing the conductivity of the sulfur cathode and moderating the dissolution of lithium polysulfides are two key factors for the success of lithium-sulfur batteries. Here we report a sulfur host that overcomes both obstacles at once. With inherent metallic conductivity and strong adsorption capability for lithium-polysulfides, titanium monoxide@carbon hollow nanospheres can not only generate sufficient electrical contact to the insulating sulfur for high capacity, but also effectively confine lithium-polysulfides for prolonged cycle life. Additionally, the designed composite cathode further maximizes the lithium-polysulfide restriction capability by using the polar shells to prevent their outward diffusion, which avoids the need for chemically bonding all lithium-polysulfides on the surfaces of polar particles.

  15. Roles of sulfuric acid in elemental mercury removal by activated carbon and sulfur-impregnated activated carbon.

    Science.gov (United States)

    Morris, Eric A; Kirk, Donald W; Jia, Charles Q; Morita, Kazuki

    2012-07-17

    This work addresses the discrepancy in the literature regarding the effects of sulfuric acid (H(2)SO(4)) on elemental Hg uptake by activated carbon (AC). H(2)SO(4) in AC substantially increased Hg uptake by absorption particularly in the presence of oxygen. Hg uptake increased with acid amount and temperature exceeding 500 mg-Hg/g-AC after 3 days at 200 °C with AC treated with 20% H(2)SO(4). In the absence of other strong oxidizers, oxygen was able to oxidize Hg. Upon oxidation, Hg was more readily soluble in the acid, greatly enhancing its uptake by acid-treated AC. Without O(2), S(VI) in H(2)SO(4) was able to oxidize Hg, thus making it soluble in H(2)SO(4). Consequently, the presence of a bulk H(2)SO(4) phase within AC pores resulted in an orders of magnitude increase in Hg uptake capacity. However, the bulk H(2)SO(4) phase lowered the AC pore volume and could block the access to the active surface sites and potentially hinder Hg uptake kinetics. AC treated with SO(2) at 700 °C exhibited a much faster rate of Hg uptake attributed to sulfur functional groups enhancing adsorption kinetics. SO(2)-treated carbon maintained its fast uptake kinetics even after impregnation by 20% H(2)SO(4).

  16. Graphene-wrapped sulfur/metal organic framework-derived microporous carbon composite for lithium sulfur batteries

    Directory of Open Access Journals (Sweden)

    Renjie Chen

    2014-12-01

    Full Text Available A three-dimensional hierarchical sandwich-type graphene sheet-sulfur/carbon (GS-S/CZIF8-D composite for use in a cathode for a lithium sulfur (Li-S battery has been prepared by an ultrasonic method. The microporous carbon host was prepared by a one-step pyrolysis of Zeolitic Imidazolate Framework-8 (ZIF-8, a typical zinc-containing metal organic framework (MOF, which offers a tunable porous structure into which electro-active sulfur can be diffused. The thin graphene sheet, wrapped around the sulfur/zeolitic imidazolate framework-8 derived carbon (S/CZIF8-D composite, has excellent electrical conductivity and mechanical flexibility, thus facilitating rapid electron transport and accommodating the changes in volume of the sulfur electrode. Compared with the S/CZIF8-D sample, Li-S batteries with the GS-S/CZIF8-D composite cathode showed enhanced capacity, improved electrochemical stability, and relatively high columbic efficiency by taking advantage of the synergistic effects of the microporous carbon from ZIF-8 and a highly interconnected graphene network. Our results demonstrate that a porous MOF-derived scaffold with a wrapped graphene conductive network structure is a potentially efficient design for a battery electrode that can meet the challenge arising from low conductivity and volume change.

  17. Graphene-wrapped sulfur/metal organic framework-derived microporous carbon composite for lithium sulfur batteries

    Science.gov (United States)

    Chen, Renjie; Zhao, Teng; Tian, Tian; Cao, Shuai; Coxon, Paul R.; Xi, Kai; Fairen-Jimenez, David; Vasant Kumar, R.; Cheetham, Anthony K.

    2014-12-01

    A three-dimensional hierarchical sandwich-type graphene sheet-sulfur/carbon (GS-S/CZIF8-D) composite for use in a cathode for a lithium sulfur (Li-S) battery has been prepared by an ultrasonic method. The microporous carbon host was prepared by a one-step pyrolysis of Zeolitic Imidazolate Framework-8 (ZIF-8), a typical zinc-containing metal organic framework (MOF), which offers a tunable porous structure into which electro-active sulfur can be diffused. The thin graphene sheet, wrapped around the sulfur/zeolitic imidazolate framework-8 derived carbon (S/CZIF8-D) composite, has excellent electrical conductivity and mechanical flexibility, thus facilitating rapid electron transport and accommodating the changes in volume of the sulfur electrode. Compared with the S/CZIF8-D sample, Li-S batteries with the GS-S/CZIF8-D composite cathode showed enhanced capacity, improved electrochemical stability, and relatively high columbic efficiency by taking advantage of the synergistic effects of the microporous carbon from ZIF-8 and a highly interconnected graphene network. Our results demonstrate that a porous MOF-derived scaffold with a wrapped graphene conductive network structure is a potentially efficient design for a battery electrode that can meet the challenge arising from low conductivity and volume change.

  18. Sulfur loaded in micropore-rich carbon aerogel as cathode of lithium-sulfur battery with improved cyclic stability

    Science.gov (United States)

    Li, Zihao; Li, Xiaogang; Liao, Youhao; Li, Xiaoping; Li, Weishan

    2016-12-01

    We report a novel composite of sulfur loaded in micropore-rich carbon aerogel (CA-S), as cathode of lithium-sulfur battery. Carbon aerogel (CA) is synthesized through phenol-formaldehyde reaction with a low catalyst concentration and carbonization under high temperature, and loaded with sulfur via chemical deposition and heat treatment. The physical properties of the resulting CA and the electrochemical performances of the resulting CA-S are investigated by scanning electron microscopy, thermal gravimetric analysis, Brunauer-Emmett-Teller characterization, electrochemical impedance spectroscopy, and galvanostatic discharge/charge test, with a comparison of a common carbon material, acetylene black (AB), and sulfur loaded in AB (AB-S). It is found that the CA is micropore-rich with micropore volume over 66% of total pore volume, and the CA-S exhibits significantly improved cyclic stability compared with AB-S. The improved performance of CA-S is attributed to the confinement of the micropores in CA to small sulfur allotropes and corresponding lithium sulfides.

  19. Graphene-wrapped sulfur/metal organic framework-derived microporous carbon composite for lithium sulfur batteries

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Renjie, E-mail: kx210@cam.ac.uk, E-mail: chenrj@bit.edu.cn; Zhao, Teng [Beijing Key Laboratory of Environmental Science and Engineering, School of Chemical Engineering and Environment, Beijing Institute of Technology, Beijing 100081 (China); Department of Materials Science and Metallurgy, University of Cambridge, Cambridge CB3 0FS (United Kingdom); Tian, Tian; Fairen-Jimenez, David [Department of Chemical Engineering and Biotechnology, University of Cambridge, Pembroke Street, Cambridge CB2 3RA (United Kingdom); Cao, Shuai; Coxon, Paul R.; Xi, Kai, E-mail: kx210@cam.ac.uk, E-mail: chenrj@bit.edu.cn; Vasant Kumar, R.; Cheetham, Anthony K. [Department of Materials Science and Metallurgy, University of Cambridge, Cambridge CB3 0FS (United Kingdom)

    2014-12-01

    A three-dimensional hierarchical sandwich-type graphene sheet-sulfur/carbon (GS-S/C{sub ZIF8-D}) composite for use in a cathode for a lithium sulfur (Li-S) battery has been prepared by an ultrasonic method. The microporous carbon host was prepared by a one-step pyrolysis of Zeolitic Imidazolate Framework-8 (ZIF-8), a typical zinc-containing metal organic framework (MOF), which offers a tunable porous structure into which electro-active sulfur can be diffused. The thin graphene sheet, wrapped around the sulfur/zeolitic imidazolate framework-8 derived carbon (S/C{sub ZIF8-D}) composite, has excellent electrical conductivity and mechanical flexibility, thus facilitating rapid electron transport and accommodating the changes in volume of the sulfur electrode. Compared with the S/C{sub ZIF8-D} sample, Li-S batteries with the GS-S/C{sub ZIF8-D} composite cathode showed enhanced capacity, improved electrochemical stability, and relatively high columbic efficiency by taking advantage of the synergistic effects of the microporous carbon from ZIF-8 and a highly interconnected graphene network. Our results demonstrate that a porous MOF-derived scaffold with a wrapped graphene conductive network structure is a potentially efficient design for a battery electrode that can meet the challenge arising from low conductivity and volume change.

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

    Science.gov (United States)

    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 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.

  1. Discharge-charge process of the porous sulfur/carbon nanocomposite cathode for rechargeable lithium sulfur batteries

    Science.gov (United States)

    Gao, Mengyao; Xiong, Xing; Wang, Weikun; Zhao, Shengrong; Li, Chengming; Zhang, Hao; Yu, Zhongbao; Huang, Yaqin

    2014-02-01

    The discharge-charge process of the porous sulfur/carbon nanocomposite cathode has been investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), electrochemical impedance spectroscopy (EIS), and energy-dispersive X-ray spectroscopy (EDS). The results indicate that the porous nanocomposite enhances the electrolyte infiltrate into the cathode materials evenly, has a good capability of confining the soluble polysulfides and preventing the aggregation of insoluble Li2S. The regenerated elemental sulfur of the porous sulfur/carbon nanocomposite cathode exists in nano-size particles in the pore and the resistance decreases compared with the original cathode. Moreover, the porous nanocomposite realizes the micro-reactors during the discharge-charge process and can accommodate the volume change which is benefit for stabilization of the cathode during the electrochemical reaction.

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

    Science.gov (United States)

    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.

  3. Carbon and sulfur budget of the silicate Earth explained by accretion of differentiated planetary embryos

    Science.gov (United States)

    Li, Yuan; Dasgupta, Rajdeep; Tsuno, Kyusei; Monteleone, Brian; Shimizu, Nobumichi

    2016-10-01

    The abundances of volatile elements in the Earth's mantle have been attributed to the delivery of volatile-rich material after the main phase of accretion. However, no known meteorites could deliver the volatile elements, such as carbon, nitrogen, hydrogen and sulfur, at the relative abundances observed for the silicate Earth. Alternatively, Earth could have acquired its volatile inventory during accretion and differentiation, but the fate of volatile elements during core formation is known only for a limited set of conditions. Here we present constraints from laboratory experiments on the partitioning of carbon and sulfur between metallic cores and silicate mantles under conditions relevant for rocky planetary bodies. We find that carbon remains more siderophile than sulfur over a range of oxygen fugacities; however, our experiments suggest that in reduced or sulfur-rich bodies, carbon is expelled from the segregating core. Combined with previous constraints, we propose that the ratio of carbon to sulfur in the silicate Earth could have been established by differentiation of a planetary embryo that was then accreted to the proto-Earth. We suggest that the accretion of a Mercury-like (reduced) or a sulfur-rich (oxidized) differentiated body--in which carbon has been preferentially partitioned into the mantle--may explain the Earth's carbon and sulfur budgets.

  4. Combined effect of sulfur dioxide and carbon dioxide gases on mold fungi

    Energy Technology Data Exchange (ETDEWEB)

    Kochurova, A.I.; Karpova, T.N.

    1974-01-01

    Sulfur dioxide at 0.08% killed Penicillium expansum, Stemphylium macrosporium, and Botrytis cinerea within 24 hours. At 0.2%, it killed P. citrinum, Alternaria tenuis, and Fusarium moniliforme. Sulfur dioxide (at 0.04%) and Sulfur dioxide-carbon dioxide mixtures (at 0.02 and 5% respectively) completely suppressed the growth of P. citrinum, P. expansum, P. rubrum, A. tenuis, S. macrosporium, B. cinerea, and F. moniliforme in laboratory experiments. 1 table.

  5. Polydopamine-coated, nitrogen-doped, hollow carbon-sulfur double-layered core-shell structure for improving lithium-sulfur batteries.

    Science.gov (United States)

    Zhou, Weidong; Xiao, Xingcheng; Cai, Mei; Yang, Li

    2014-09-10

    To better confine the sulfur/polysulfides in the electrode of lithium-sulfur (Li/S) batteries and improve the cycling stability, we developed a double-layered core-shell structure of polymer-coated carbon-sulfur. Carbon-sulfur was first prepared through the impregnation of sulfur into hollow carbon spheres under heat treatment, followed by a coating polymerization to give a double-layered core-shell structure. From the study of scanning transmission electron microscopy (STEM) images, we demonstrated that the sulfur not only successfully penetrated through the porous carbon shell but also aggregated along the inner wall of the carbon shell, which, for the first time, provided visible and convincing evidence that sulfur preferred diffusing into the hollow carbon rather than aggregating in/on the porous wall of the carbon. Taking advantage of this structure, a stable capacity of 900 mA h g(-1) at 0.2 C after 150 cycles and 630 mA h g(-1) at 0.6 C after 600 cycles could be obtained in Li/S batteries. We also demonstrated the feasibility of full cells using the sulfur electrodes to couple with the silicon film electrodes, which exhibited significantly improved cycling stability and efficiency. The remarkable electrochemical performance could be attributed to the desirable confinement of sulfur through the unique double-layered core-shell architectures.

  6. Fundamental aspects of recoupled pair bonds. I. Recoupled pair bonds in carbon and sulfur monofluoride

    Energy Technology Data Exchange (ETDEWEB)

    Dunning, Thom H., E-mail: thdjr@uw.edu; Xu, Lu T.; Takeshita, Tyler Y. [Department of Chemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, Illinois 61801 (United States)

    2015-01-21

    The number of singly occupied orbitals in the ground-state atomic configuration of an element defines its nominal valence. For carbon and sulfur, with two singly occupied orbitals in their {sup 3}P ground states, the nominal valence is two. However, in both cases, it is possible to form more bonds than indicated by the nominal valence—up to four bonds for carbon and six bonds for sulfur. In carbon, the electrons in the 2s lone pair can participate in bonding, and in sulfur the electrons in both the 3p and 3s lone pairs can participate. Carbon 2s and sulfur 3p recoupled pair bonds are the basis for the tetravalence of carbon and sulfur, and 3s recoupled pair bonds enable sulfur to be hexavalent. In this paper, we report generalized valence bond as well as more accurate calculations on the a{sup 4}Σ{sup −} states of CF and SF, which are archetypal examples of molecules that possess recoupled pair bonds. These calculations provide insights into the fundamental nature of recoupled pair bonds and illustrate the key differences between recoupled pair bonds formed with the 2s lone pair of carbon, as a representative of the early p-block elements, and recoupled pair bonds formed with the 3p lone pair of sulfur, as a representative of the late p-block elements.

  7. Hybrid nanostructured microporous carbon-mesoporous carbon doped titanium dioxide/sulfur composite positive electrode materials for rechargeable lithium-sulfur batteries

    Science.gov (United States)

    Zegeye, Tilahun Awoke; Kuo, Chung-Feng Jeffrey; Wotango, Aselefech Sorsa; Pan, Chun-Jern; Chen, Hung-Ming; Haregewoin, Atetegeb Meazah; Cheng, Ju-Hsiang; Su, Wei-Nien; Hwang, Bing-Joe

    2016-08-01

    Herein, we design hybrid nanostructured microporous carbon-mesoporous carbon doped titanium dioxide/sulfur composite (MC-Meso C-doped TiO2/S) as a positive electrode material for lithium-sulfur batteries. The hybrid MC-Meso C-doped TiO2 host material is produced by a low-cost, hydrothermal and annealing process. The resulting conductive material shows dual microporous and mesoporous behavior which enhances the effective trapping of sulfur and polysulfides. The hybrid MC-Meso C-doped TiO2/S composite material possesses rutile TiO2 nanotube structure with successful carbon doping while sulfur is uniformly distributed in the hybrid MC-Meso C-doped TiO2 composite materials after the melt-infusion process. The electrochemical measurement of the hybrid material also shows improved cycle stability and rate performance with high sulfur loading (61.04%). The material delivers an initial discharge capacity of 802 mAh g-1 and maintains it at 578 mAh g-1 with a columbic efficiency greater than 97.1% after 140 cycles at 0.1 C. This improvement is thought to be attributed to the unique hybrid nanostructure of the MC-Meso C-doped TiO2 host and the good dispersion of sulfur in the narrow pores of the MC spheres and the mesoporous C-doped TiO2 support.

  8. Porous Coconut Shell Carbon Offering High Retention and Deep Lithiation of Sulfur for Lithium-Sulfur batteries.

    Science.gov (United States)

    Chen, Zhaohui; Du, Xue-Li; He, Jian-Bo; Li, Fang; Wang, Yan; Li, Yu-Lin; Li, Bing; Xin, Sen

    2017-09-14

    Retaining soluble polysulfides in the sulfur cathodes and allowing for the deep redox are essential to develop high performance lithium-sulfur batteries. The versatile textures and physicochemical characteristics of abundant biomass offer a great opportunity to prepare biochar materials that can enhance the performance of Li-S batteries in sustainable mode. Here, we exploit micro/mesoporous coconut shell carbon (CSC) with high specific surface areas as a sulfur host for Li-S batteries. The sulfur-infiltrated CSC materials show superior discharge-charge capacity, cycling stability and high-rate capability. High discharge capacities of 1599 and 1500 mA h g-1 were achieved at current rates of 0.5 and 2.0 C, respectively. A high reversible capacity of 517 mA h g-1 was retained at 2.0 C even after 400 cycles. The results demonstrate a high retention and a deep lithiation of the CSC-confined sulfur. The success of this strategy provides insight into seeking high-performance biochar materials for Li-S batteries from abundant bio-resources.

  9. Foldable interpenetrated metal-organic frameworks/carbon nanotubes thin film for lithium-sulfur batteries

    Science.gov (United States)

    Mao, Yiyin; Li, Gaoran; Guo, Yi; Li, Zhoupeng; Liang, Chengdu; Peng, Xinsheng; Lin, Zhan

    2017-03-01

    Lithium-sulfur batteries are promising technologies for powering flexible devices due to their high energy density, low cost and environmental friendliness, when the insulating nature, shuttle effect and volume expansion of sulfur electrodes are well addressed. Here, we report a strategy of using foldable interpenetrated metal-organic frameworks/carbon nanotubes thin film for binder-free advanced lithium-sulfur batteries through a facile confinement conversion. The carbon nanotubes interpenetrate through the metal-organic frameworks crystal and interweave the electrode into a stratified structure to provide both conductivity and structural integrity, while the highly porous metal-organic frameworks endow the electrode with strong sulfur confinement to achieve good cyclability. These hierarchical porous interpenetrated three-dimensional conductive networks with well confined S8 lead to high sulfur loading and utilization, as well as high volumetric energy density.

  10. Foldable interpenetrated metal-organic frameworks/carbon nanotubes thin film for lithium-sulfur batteries.

    Science.gov (United States)

    Mao, Yiyin; Li, Gaoran; Guo, Yi; Li, Zhoupeng; Liang, Chengdu; Peng, Xinsheng; Lin, Zhan

    2017-03-06

    Lithium-sulfur batteries are promising technologies for powering flexible devices due to their high energy density, low cost and environmental friendliness, when the insulating nature, shuttle effect and volume expansion of sulfur electrodes are well addressed. Here, we report a strategy of using foldable interpenetrated metal-organic frameworks/carbon nanotubes thin film for binder-free advanced lithium-sulfur batteries through a facile confinement conversion. The carbon nanotubes interpenetrate through the metal-organic frameworks crystal and interweave the electrode into a stratified structure to provide both conductivity and structural integrity, while the highly porous metal-organic frameworks endow the electrode with strong sulfur confinement to achieve good cyclability. These hierarchical porous interpenetrated three-dimensional conductive networks with well confined S8 lead to high sulfur loading and utilization, as well as high volumetric energy density.

  11. Foldable interpenetrated metal-organic frameworks/carbon nanotubes thin film for lithium–sulfur batteries

    Science.gov (United States)

    Mao, Yiyin; Li, Gaoran; Guo, Yi; Li, Zhoupeng; Liang, Chengdu; Peng, Xinsheng; Lin, Zhan

    2017-01-01

    Lithium–sulfur batteries are promising technologies for powering flexible devices due to their high energy density, low cost and environmental friendliness, when the insulating nature, shuttle effect and volume expansion of sulfur electrodes are well addressed. Here, we report a strategy of using foldable interpenetrated metal-organic frameworks/carbon nanotubes thin film for binder-free advanced lithium–sulfur batteries through a facile confinement conversion. The carbon nanotubes interpenetrate through the metal-organic frameworks crystal and interweave the electrode into a stratified structure to provide both conductivity and structural integrity, while the highly porous metal-organic frameworks endow the electrode with strong sulfur confinement to achieve good cyclability. These hierarchical porous interpenetrated three-dimensional conductive networks with well confined S8 lead to high sulfur loading and utilization, as well as high volumetric energy density. PMID:28262801

  12. The correlation between carbon structures and electrochemical properties of sulfur/carbon composites for Li-S batteries

    Science.gov (United States)

    Du, Zhenzhen; Xu, Jin; Jin, Song; Shi, Yuchen; Guo, Chengkun; Kong, Xianghua; Zhu, Yanwu; Ji, Hengxing

    2017-02-01

    The structures of carbon materials greatly affect the electrochemical properties of sulfur/carbon composites for lithium-sulfur (Li-S) batteries. Understanding the effect of carbon structure factors on the electrochemical properties of sulfur/carbon composites helps in rational designing of the cathode material for optimized battery performance. We prepare reduced graphene oxide (RGO), cysteine-modified RGO (RGO-CYS), microwave-expanded graphite oxide (MEGO) and activated-MEGO (aMEGO) with specific surface areas (SSA) of 58-3010 m2 g-1, C/O atomic ratios of 2.41-10.81, pore sizes of 0.9-5.6 nm and pore volumes of 0.14-2.03 cm3 g-1. The electrochemical performance researches S/RGO-CYS > S/RGO > S/MEGO > S/aMEGO when it is listed in the order of their specific capacity, rate capability and cyclic life. And the S/RGO-CYS delivers a high reversible capacity of 455 mA h g-1 at 8 C. The excellent performance of S/RGO-CYS composite is ascribed to the sulfur-containing functional groups of the RGO-CYS, which helps the sulfur dispersion and stabilizes the dissoluble lithium polysulfides. Our results demonstrate that the surface chemistry of carbon materials plays a more important role than the SSA, pore size and pore volume for the electrochemical properties of sulfur/carbon composites for Li-S batteries.

  13. Co3O4-Carbon Cloth free standing cathode for lithium sulfur battery

    Science.gov (United States)

    Xu, Jing; Su, Dawei; Wang, Guoxiu

    2017-07-01

    Lithium-sulfur (Li-S) battery has been considered to be one of the most promising next-generation electrochemical energy-storage systems due to its high theoretical energy of 2600 Wh kg-1 with low cost. The insulating nature of both sulfur and the dissolution of polysulfides are the two primary challenges for the application of lithium sulfur batteries. Here, we developed a binder-free cathode by chemisorption of Co3O4 to carbon cloth (CC), which was used as a 3D current collector to accommodate a large amount of sulfur, multiwall carbon nanofiber (MWCNF) and carbon black (CB) hybrids within the conductive scaffold, enabling the fabrication of ultrahigh sulfur loaded electrodes. The interconnected carbon fibers established a long-range conductive matrix for an efficient electron transport, the multiple conductive pathways guarantee high sulfur utilization. More importantly, the high electrolyte absorbability of the Co3O4-CC-S current collector facilitates well-localized polysulfides within the Co3O4-CC-S, meanwhile, the polar Co3O4 could also effectively entrapped the intermediated polysulfides preventing their free diffusion to the lithium anode, guaranteeing good cycling stability. Consequently, the Co3O4-CC-S electrodes exhibit excellent electrochemical performance with sulfur loading of 4.3 mg cm-2.

  14. Sulfur/graphitic hollow carbon sphere nano-composite as a cathode material for high-power lithium-sulfur battery.

    Science.gov (United States)

    Shin, Eon Sung; Kim, Min-Seop; Cho, Won Il; Oh, Si Hyoung

    2013-08-03

    The intrinsic low conductivity of sulfur which leads to a low performance at a high current rate is one of the most limiting factors for the commercialization of lithium-sulfur battery. Here, we present an easy and convenient method to synthesize a mono-dispersed hollow carbon sphere with a thin graphitic wall which can be utilized as a support with a good electrical conductivity for the preparation of sulfur/carbon nano-composite cathode. The hollow carbon sphere was prepared from the pyrolysis of the homogenous mixture of the mono-dispersed spherical silica and Fe-phthalocyanine powder in elevated temperature. The composite cathode was manufactured by infiltrating sulfur melt into the inner side of the graphitic wall. The electrochemical cycling shows a capacity of 425 mAh g-1 at 3 C current rate which is more than five times larger than that for the sulfur/carbon black nano-composite prepared by simple ball milling.

  15. Hollow Carbon Nanofiber-Encapsulated Sulfur Cathodes for High Specific Capacity Rechargeable Lithium Batteries

    KAUST Repository

    Zheng, Guangyuan

    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 Li2S 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 LiNO3 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. © 2011 American Chemical Society.

  16. Proof of concept for a novel, binder-free and conducting carbon-free sulfur battery cathode: Composite electroformation of copper foil with incorporated polythiophene wrapped sulfur particles

    Science.gov (United States)

    Erhardt, Claudia; Sörgel, Şeniz; Meinhard, Sandra; Sörgel, Timo

    2015-11-01

    This work, for the first time, presents sulfur electrodes for lithium/sulfur (Li/S) batteries produced by a newly developed single-step electroforming process, which allows simultaneous sulfur incorporation during electroformation of an electrically conducting electrode. This metal is used as binding matrix for the sulfur particles and thereby makes any binder and conducting carbon additives redundant. Furthermore, it serves by itself as the current collector, so that all functionalities (current collector, binder and electrical conductor towards sulfur) are fulfilled by the electroformed metal, while modified sulfur particles are directly incorporated (composite electroformation). In this way, the sulfur cathode can be produced in a single continuous step in form of a metal foil with adjustable thickness and sulfur loading. The process requires functionalization of sulfur to improve its wettability, incorporation homogeneity and volume which is provided by wrapping sulfur particles with polythiophene. Electroformed copper-sulfur composite foils are chosen as a first proof of the new concept. The achieved battery capacity, cycling stability and coulombic efficiency are presented. It is shown that the electroformed copper-sulfur composite foil operates very well as a battery cathode and a discharge capacity of over 400 mAh g-1 at a rate of 0.5 C over 100 cycles is preserved.

  17. Sulfur and strontium isotopic compositions of carbonate and evaporite rocks from the late Neoproterozoic–early Cambrian Bilara Group (Nagaur-Ganganagar Basin, India): Constraints on intrabasinal correlation and global sulfur cycle

    Digital Repository Service at National Institute of Oceanography (India)

    Mazumdar, A.; Strauss, H.

    Sulfur and strontium isotope ratios are presented for carbonate and evaporite rocks from the late Neoproterozoic and early Cambrian Bilara and Hanseran Evaporite Groups, NW India. The sulfur isotopic compositions of trace sulfate in carbonate rocks...

  18. Nanostructured nitrogen-doped mesoporous carbon derived from polyacrylonitrile for advanced lithium sulfur batteries

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Ying; Zhao, Xiaohui; Chauhan, Ghanshyam S. [Department of Chemical Engineering and Research Institute for Green Energy Convergence Technology, Gyeongsang National University, 501 Jinju-daero, Jinju 660-701 (Korea, Republic of); Ahn, Jou-Hyeon, E-mail: jhahn@gnu.ac.kr [Department of Chemical Engineering and Research Institute for Green Energy Convergence Technology, Gyeongsang National University, 501 Jinju-daero, Jinju 660-701 (Korea, Republic of); Department of Materials Engineering and Convergence Technology and RIGET, Gyeongsang National University, 501 Jinju-daero, Jinju 660-701 (Korea, Republic of)

    2016-09-01

    Graphical abstract: Well-ordered nitrogen-doped mesoporous carbon materials were prepared by in-situ polymerization of polyacrylonitrile in SBA-15 template. The composite of sulfur and nitrogen-doped carbon was successfully used as a cathode material for lithium sulfur battery. - Highlights: • N-doped mesoporous carbons were prepared with PAN as carbon source. • Highly ordered pore system facilitates sulfur loading. • Ladder-type carbon matrix provides good structural stability for confining sulfur. • N-doping ensures an improved absorbability of soluble polysulfides. - Abstract: Nitrogen doping in carbon matrix can effectively improve the wettability of electrolyte and increase electric conductivity of carbon by ensuring fast transfer of ions. We synthesized a series of nitrogen-doped mesoporous carbons (CPANs) via in situ polymerization of polyacrylonitrile (PAN) in SBA-15 template followed by carbonization at different temperatures. Carbonization results in the formation of ladder structure which enhances the stability of the matrix. In this study, CPAN-800, carbon matrix synthesized by the carbonization at 800 °C, was found to possess many desirable properties such as high specific surface area and pore volume, moderate nitrogen content, and highly ordered mesoporous structure. Therefore, it was used to prepare S/CPAN-800 composite as cathode material in lithium sulfur (Li-S) batteries. The S/CPAN-800 composite was proved to be an excellent material for Li-S cells which delivered a high initial discharge capacity of 1585 mAh g{sup −1} and enhanced capacity retention of 862 mAh g{sup −1} at 0.1 C after 100 cycles.

  19. Corrosion by concentrated sulfuric acid in carbon steel pipes and tanks: state of the art

    Energy Technology Data Exchange (ETDEWEB)

    Panossian, Zehbour; Almeida, Neusvaldo Lira de; Sousa, Raquel Maria Ferreira de [Instituto de Pesquisas Tecnologicas (IPT), Sao Paulo, SP (Brazil); Pimenta, Gutemberg de Souza [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil). Centro de Pesquisas e Desenvolvimento (CENPES); Marques, Leandro Bordalo Schmidt [PETROBRAS Engenharia, Rio de Janeiro, RJ (Brazil)

    2009-07-01

    PETROBRAS, allied to the policy of reduction of emission of pollutants, has been adjusting the processes of the new refineries to obtain products with lower sulfur content. Thus, the sulfur dioxide, extracted from the process gases of a new refinery to be built in the Northeast, will be used to produce sulfuric acid with concentration between (94-96) %. This acid will be stored in carbon steel tanks and transported through a buried 8-km carbon steel pipe from the refinery to a pier, where it will be loaded onto ships and sent to the consumer markets. Therefore, the corrosion resistance of carbon steel by concentrated acid will become a great concern for the mentioned storage and transportation. When the carbon steel comes into contact with concentrated sulfuric acid, there is an immediate acid attack with the formation of hydrogen gas and ferrous ions which, in turn, forms a protective layer of FeSO{sub 4} on the metallic surface. The durability of the tanks and pipes made of carbon steel will depend on the preservation of this protective layer. This work presents a review of the carbon steel corrosion in concentrated sulfuric acid and discusses the preventive methods against this corrosion, including anodic protection. (author)

  20. Possible Decoupling of the Geochemical Cycles of Sulfur and Carbon During the Early Cretaceous (Hauterivian)

    Science.gov (United States)

    Kristall, B.; Hurtgen, M. T.; Sageman, B. B.

    2013-12-01

    During the past decade there has been significant focus on understanding the global sulfur cycle during the Mid- to Late-Cretaceous. The occurrence of several oceanic anoxic events (OAEs) during this time period and the relationships among the sulfur, carbon, and oxygen cycles controlling the redox state of the ocean have been motivating factors in this research. These efforts have centered on identifying what impact, if any, massive volcanism and evaporite deposition associated with opening of the South Atlantic had on the sulfate content of the ocean and what role these events may have played in triggering OAEs. However, relatively little work has been done to characterize the sulfur cycle during the Early Cretaceous. In the present study, we have analyzed the sulfur isotope composition of carbonate-associated sulfate (CAS) from Hauterivian-aged samples (Resolution Guyot ODP Hole 866A). We found a previously unrecognized ~4‰ positive sulfur isotope excursion in sulfate sulfur. This well structured, excursion spans approximately 15-20 m of core and is estimated to be less than 300-500 kyr. Corresponding carbonate carbon isotope analyses do not show a comparable, well-structured excursion. During this event δ13C values vary only by 0.25-0.5‰. The rapid shift and recovery in δ34Ssulfate suggests either that this event was regional or that the Early Cretaceous oceans contained low sulfate levels (factors necessary to produce the observed S isotope shift without a corresponding change in C isotope composition.

  1. Sulfur-infiltrated porous carbon microspheres with controllable multi-modal pore size distribution for high energy lithium-sulfur batteries.

    Science.gov (United States)

    Zhao, Cunyu; Liu, Lianjun; Zhao, Huilei; Krall, Andy; Wen, Zhenhai; Chen, Junhong; Hurley, Patrick; Jiang, Junwei; Li, Ying

    2014-01-21

    Sulfur has received increasing attention as a cathode material for lithium-sulfur (Li-S) batteries due to its high theoretical specific capacity. However, the commercialization of Li-S batteries is limited by the challenges of poor electrical conductivity of sulfur, dissolution of the polysulfide intermediates into the electrolyte, and volume expansion of sulfur during cycling. Herein, we report the fabrication of novel-structured porous carbon microspheres with a controllable multi-modal pore size distribution, i.e., a combination of interconnected micropores, mesopores and macropores. Cathodes made of sulfur infiltrated in such a hierarchical carbon framework provide several advantages: (1) a continuous and high surface area carbon network for enhanced electrical conductivity and high sulfur loading; (2) macropores and large mesopores bridged by small mesopores to provide good electrolyte accessibility and fast Li ion transport and to accommodate volume expansion of sulfur; and (3) small mesopores and micropores to improve carbon/sulfur interaction and to help trap polysulfides. An initial discharge capacity at 1278 mA h g(-1) and capacity retention at 70.7% (904 mA h g(-1)) after 100 cycles at a high rate (1 C) were achieved. The material fabrication process is relatively simple and easily scalable.

  2. [Effect of dissolved oxygen on microbial community in simultaneous removal of carbon, nitrogen and sulfur process].

    Science.gov (United States)

    Yu, Hao; Chen, Chuan; Zhang, Li; Wang, Ai-Jie

    2013-06-01

    In order to investigate the effect of dissolved oxygen (DO) on microbial community in simultaneous removal of carbon, nitrogen and sulfur process and reveal the mechanism of high elemental sulfur conversion rate under aerobic condition, GeoChip was employed to characterize the structure of microbial community. The results indicated that the microbial community structure significantly changed with different aerobic conditions (P bacteria (SRB) with the changing DO. The relative abundance of sox gene showed significant difference between aeration rate of 20 mL x min(-1) and aeration rate of 0 mL x min(-1), which might suggest that the activity of sulfur-oxidizing bacteria (SOB) was obviously improved by DO. Moreover, cluster analysis of sox gene confirmed this suggestion, with higher signal intensity found in numbers of probes derived from SOB under such aerobic conditions. Overall, the results revealed a positive effect of micro-aerobic conditions on the simultaneous removal of carbon, nitrogen and sulfur process.

  3. Effect of Sulfur Concentration on the Morphology of Carbon Nanofibers Produced from a Botanical Hydrocarbon

    Directory of Open Access Journals (Sweden)

    Ghosh Kaushik

    2008-01-01

    Full Text Available AbstractCarbon nanofibers (CNF with diameters of 20–130 nm with different morphologies were obtained from a botanical hydrocarbon: Turpentine oil, using ferrocene as catalyst source and sulfur as a promoter by simple spray pyrolysis method at 1,000 °C. The influence of sulfur concentration on the morphology of the carbon nanofibers was investigated. SEM, TEM, Raman, TGA/DTA, and BET surface area were employed to characterize the as-prepared samples. TEM analysis confirms that as-prepared CNFs have a very sharp tip, bamboo shape, open end, hemispherical cap, pipe like morphology, and metal particle trapped inside the wide hollow core. It is observed that sulfur plays an important role to promote or inhibit the CNF growth. Addition of sulfur to the solution of ferrocene and turpentine oil mixture was found to be very effective in promoting the growth of CNF. Without addition of sulfur, carbonaceous product was very less and mainly soot was formed. At high concentration of sulfur inhibit the growth of CNFs. Hence the yield of CNFs was optimized for a given sulfur concentration.

  4. Distribution of Hydrogen Peroxide, Carbon Dioxide, and Sulfuric Acid in Europa's Icy Crust

    Science.gov (United States)

    Carlson, R. W.

    2004-01-01

    Galileo's Near Infrared Mapping Spectrometer (NIMS) detected hydrogen peroxide, carbon dioxide and a hydrated material on Europa's surface, the latter interpreted as hydrated sulfuric acid (H2SO4*nH2O) or hydrated salts. Related compounds are molecular oxygen, sulfur dioxide, and two chromophores, one that is dark in the ultraviolet(UV) and concentrated on the trailing side, the other brighter in the UV and preferentially distributed in the leading hemisphere. The UV-dark material has been suggested to be sulfur.

  5. Chloride-Reinforced Carbon Nanofiber Host as Effective Polysulfide Traps in Lithium-Sulfur Batteries.

    Science.gov (United States)

    Fan, Lei; Zhuang, Houlong L; Zhang, Kaihang; Cooper, Valentino R; Li, Qi; Lu, Yingying

    2016-12-01

    Lithium-sulfur (Li-S) battery is one of the most promising alternatives for the current state-of-the-art lithium-ion batteries due to its high theoretical energy density and low production cost from the use of sulfur. However, the commercialization of Li-S batteries has been so far limited to the cyclability and the retention of active sulfur materials. Using co-electrospinning and physical vapor deposition procedures, we created a class of chloride-carbon nanofiber composites, and studied their effectiveness on polysulfides sequestration. By trapping sulfur reduction products in the modified cathode through both chemical and physical confinements, these chloride-coated cathodes are shown to remarkably suppress the polysulfide dissolution and shuttling between lithium and sulfur electrodes. From adsorption experiments and theoretical calculations, it is shown that not only the sulfide-adsorption effect but also the diffusivity in the vicinity of these chlorides materials plays an important role on the reversibility of sulfur-based cathode upon repeated cycles. Balancing the adsorption and diffusion effects of these nonconductive materials could lead to the enhanced cycling performance of an Li-S cell. Electrochemical analyses over hundreds of cycles indicate that cells containing indium chloride-modified carbon nanofiber outperform cells with other halogenated salts, delivering an average specific capacity of above 1200 mAh g(-1) at 0.2 C.

  6. Macroporous Activated Carbon Derived from Rapeseed Shell for Lithium–Sulfur Batteries

    Directory of Open Access Journals (Sweden)

    Mingbo Zheng

    2017-10-01

    Full Text Available Lithium–sulfur batteries have drawn considerable attention because of their extremely high energy density. Activated carbon (AC is an ideal matrix for sulfur because of its high specific surface area, large pore volume, small-size nanopores, and simple preparation. In this work, through KOH activation, AC materials with different porous structure parameters were prepared using waste rapeseed shells as precursors. Effects of KOH amount, activated temperature, and activated time on pore structure parameters of ACs were studied. AC sample with optimal pore structure parameters was investigated as sulfur host materials. Applied in lithium–sulfur batteries, the AC/S composite (60 wt % sulfur exhibited a high specific capacity of 1065 mAh g−1 at 200 mA g−1 and a good capacity retention of 49% after 1000 cycles at 1600 mA g−1. The key factor for good cycling stability involves the restraining effect of small-sized nanopores of the AC framework on the diffusion of polysulfides to bulk electrolyte and the loss of the active material sulfur. Results demonstrated that AC materials derived from rapeseed shells are promising materials for sulfur loading.

  7. Preparation of sulfurized powdered activated carbon from waste tires using an innovative compositive impregnation process.

    Science.gov (United States)

    Yuan, Chung-Shin; Lin, Hsun-Yu; Wu, Chun-Hsin; Liu, Ming-Han; Hung, Chung-Hsuang

    2004-07-01

    The objective of this study is to develop an innovative compositive impregnation process for preparing sulfurized powdered activated carbon (PAC) from waste tires. An experimental apparatus, including a pyrolysis and activation system and a sulfur (S) impregnation system, was designed and applied to produce sulfurized PAC with a high specific surface area. Experimental tests involved the pyrolysis, activation, and sulfurization of waste tires. Waste-tire-derived PAC (WPAC) was initially produced in the pyrolysis and activation system. Experimental results indicated that the Brunauer-Emmett-Teller (BET) surface area of WPAC increased, and the average pore radius of WPAC decreased, as water feed rate and activation time increased. In this study, a conventional direct impregnation process was used to prepare the sulfurized PAC by impregnating WPAC with sodium sulfide (Na2S) solution. Furthermore, an innovative compositive impregnation process was developed and then compared with the conventional direct impregnation process. Experimental results showed that the compositive impregnation process produced the sulfurized WPAC with high BET surface area and a high S content. A maximum BET surface area of 886 m2/g and the S content of 2.61% by mass were obtained at 900 degrees C and at the S feed ratio of 2160 mg Na2S/g C. However, the direct impregnation process led to a BET surface area of sulfurized WPAC that decreased significantly as the S content increased.

  8. Self-assembly of biomorphic carbon/sulfur microstructures in sulfidic environments

    Science.gov (United States)

    Cosmidis, Julie; Templeton, Alexis S.

    2016-09-01

    In natural and laboratory-based environments experiencing sustained counter fluxes of sulfide and oxidants, elemental sulfur (S0)--a key intermediate in the sulfur cycle--can commonly accumulate. S0 is frequently invoked as a biomineralization product generated by enzymatic oxidation of hydrogen sulfide and polysulfides. Here we show the formation of S0 encapsulated in nanometre to micrometre-scale tubular and spherical organic structures that self-assemble in sulfide gradient environments in the absence of any direct biological activity. The morphology and composition of these carbon/sulfur microstructures so closely resemble microbial cellular and extracellular structures that new caution must be applied to the interpretation of putative microbial biosignatures in the fossil record. These reactions between sulfide and organic matter have important implications for our understanding of S0 mineralization processes and sulfur interactions with organic carbon in the environment. They furthermore provide a new pathway for the synthesis of carbon-sulfur nanocomposites for energy storage technologies.

  9. Elemental mercury adsorption on sulfur-impregnated porous carbon - a review.

    Science.gov (United States)

    Reddy, K Suresh Kumar; Shoaibi, Ahmed Al; Srinivasakannan, C

    2014-01-01

    The presence of elemental mercury in wellhead natural gas is an important industrial problem, since even low levels of mercury can damage cryogenic aluminium heat exchangers and other plant equipment. Mercury present in the natural gas stream will also dramatically shorten the useful life of precious metal catalysts. The present work reviews the overall process of elemental mercury removal in practice using non-regenerative adsorbents (e.g. sulfur-impregnated porous carbon), addressing the various influencing parameters such as the method of sulfur impregnation, the impregnation temperature, the sulfur to carbon ratio, the impregnation time, the impact of flue gas constituents, the effect of processing temperature, and the nature of any carbon-containing functional groups present. The distribution of elemental sulfur is found to be the key to developing an effective adsorbent, rather than quantity of sulfur impregnated. Modifying or developing an adsorbent for elemental mercury removal from natural gas needs a detail physical and chemical characteristics assessment of the adsorbent.

  10. 3D dual-confined sulfur encapsulated in porous carbon nanosheets and wrapped with graphene aerogels as a cathode for advanced lithium sulfur batteries

    Science.gov (United States)

    Hou, Yang; Li, Jianyang; Gao, Xianfeng; Wen, Zhenhai; Yuan, Chris; Chen, Junhong

    2016-04-01

    Although lithium-sulfur (Li-S) batteries have attracted much attention due to their high theoretical specific energy and low cost, their practical applications have been severely hindered by poor cycle life, inadequate sulfur utilization, and the insulating nature of sulfur. Here, we report a rationally designed Li-S cathode with a dual-confined configuration formed by confining sulfur in 2D carbon nanosheets with an abundant porous structure followed by 3D graphene aerogel wrapping. The porous carbon nanosheets act as the sulfur host and suppress the diffusion of polysulfide, while the graphene conductive networks anchor the sulfur-adsorbed carbon nanosheets, providing pathways for rapid electron/ion transport and preventing polysulfide dissolution. As a result, the hybrid electrode exhibits superior electrochemical performance, including a large reversible capacity of 1328 mA h g-1 in the first cycle, excellent cycling stability (maintaining a reversible capacity of 647 mA h g-1 at 0.2 C after 300 cycles) with nearly 100% Coulombic efficiency, and a high rate capability of 512 mA h g-1 at 8 C for 30 cycles, which is among the best reported rate capabilities.Although lithium-sulfur (Li-S) batteries have attracted much attention due to their high theoretical specific energy and low cost, their practical applications have been severely hindered by poor cycle life, inadequate sulfur utilization, and the insulating nature of sulfur. Here, we report a rationally designed Li-S cathode with a dual-confined configuration formed by confining sulfur in 2D carbon nanosheets with an abundant porous structure followed by 3D graphene aerogel wrapping. The porous carbon nanosheets act as the sulfur host and suppress the diffusion of polysulfide, while the graphene conductive networks anchor the sulfur-adsorbed carbon nanosheets, providing pathways for rapid electron/ion transport and preventing polysulfide dissolution. As a result, the hybrid electrode exhibits superior

  11. Understanding of catalyst deactivation caused by sulfur poisoning and carbon deposition in steam reforming of liquid hydrocarbon fuels

    Science.gov (United States)

    Xie, Chao

    2011-12-01

    The present work was conducted to develop a better understanding on the catalyst deactivation in steam reforming of sulfur-containing liquid hydrocarbon fuels for hydrogen production. Steam reforming of Norpar13 (a liquid hydrocarbon fuel from Exxon Mobile) without and with sulfur was performed on various metal catalysts (Rh, Ru, Pt, Pd, and Ni) supported on different materials (Al2O3, CeO2, SiO2, MgO, and CeO2- Al2O3). A number of characterization techniques were applied to study the physicochemical properties of these catalysts before and after the reactions. Especially, X-ray absorption near edge structure (XANES) spectroscopy was intensively used to investigate the nature of sulfur and carbon species in the used catalysts to reveal the catalyst deactivation mechanism. Among the tested noble metal catalysts (Rh, Ru, Pt, and Pd), Rh catalyst is the most sulfur tolerant. Al2O3 and CeO2 are much better than SiO2 and MgO as the supports for the Rh catalyst to reform sulfur-containing hydrocarbons. The good sulfur tolerance of Rh/Al2O3 can be attributed to the acidic nature of the Al2O3 support and its small Rh crystallites (1-3 nm) as these characteristics facilitate the formation of electron-deficient Rh particles with high sulfur tolerance. The good catalytic performance of Rh/CeO2 in the presence of sulfur can be ascribed to the promotion effect of CeO2 on carbon gasification, which significantly reduced the carbon deposition on the Rh/CeO2catalyst. Steam reforming of Norpar13 in the absence and presence of sulfur was further carried out over CeO2-Al2O3 supported monometallic Ni and Rh and bimetallic Rh-Ni catalysts at 550 and 800 °C. Both monometallic catalysts rapidly deactivated at 550 °C, iv 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. Sulfur K-edge XANES revealed that metal sulfide and organic sulfide are the dominant sulfur

  12. Evidence for microbial carbon and sulfur cycling in deeply buried ridge flank basalt.

    Science.gov (United States)

    Lever, Mark A; Rouxel, Olivier; Alt, Jeffrey C; Shimizu, Nobumichi; Ono, Shuhei; Coggon, Rosalind M; Shanks, Wayne C; Lapham, Laura; Elvert, Marcus; Prieto-Mollar, Xavier; Hinrichs, Kai-Uwe; Inagaki, Fumio; Teske, Andreas

    2013-03-15

    Sediment-covered basalt on the flanks of mid-ocean ridges constitutes most of Earth's oceanic crust, but the composition and metabolic function of its microbial ecosystem are largely unknown. By drilling into 3.5-million-year-old subseafloor basalt, we demonstrated the presence of methane- and sulfur-cycling microbes on the eastern flank of the Juan de Fuca Ridge. Depth horizons with functional genes indicative of methane-cycling and sulfate-reducing microorganisms are enriched in solid-phase sulfur and total organic carbon, host δ(13)C- and δ(34)S-isotopic values with a biological imprint, and show clear signs of microbial activity when incubated in the laboratory. Downcore changes in carbon and sulfur cycling show discrete geochemical intervals with chemoautotrophic δ(13)C signatures locally attenuated by heterotrophic metabolism.

  13. Removal of vapor-phase elemental mercury from stack emissions with sulfur-impregnated activated carbon.

    Science.gov (United States)

    Sowlat, Mohammad Hossein; Abdollahi, Mohammad; Gharibi, Hamed; Yunesian, Masud; Rastkari, Noushin

    2014-01-01

    This systematic review of high-quality, relevant original research articles existing in the literature was conducted to comprehensively explore the efficiency of Hg11 capture from stack emissions by sulfur-impregnated vs. virgin ACs. Our systematic overview suggested that significantly higher amounts of Hg0 are absorbed by sulfurimpregnated ACs than by virgin ones ( 1.5-32 times higher, based on the applied operational conditions). The main reason for this is because Hg11 capture by virgin ACs follows a physisorption mechanism, whereas that by sulfur-impregnated ACs occurs from a combination of physisorption of Hg11 on carbon texture and chemical reaction between Hg0 and impregnated sulfur, with subsequent formation of HgS. Temperature increased the Hg0 adsorption capacity of virgin ACs, especially when temperatures exceeded 100 oc. For sulfur-impregnated ACs, increasing the temperature up to I 00 oc increased the Hg0 adsorption capacity by enhancing the chemisorption of Hg0 capture. A further increase in temperature enhanced the efficiency of ACs that were impregnated with Sat higher temperatures (600 °C, for instance). This mainly resulted from production of stronger bonding of sulfur to carbon at higher impregnation temperatures and also from a more even distribution of sulfur in the carbon matrix. The authors of different papers reported different results with respect to whether there is an effect of initial Hg11 concentration on AC adsorption capacity. The authors of two studies could find no such etl'ect. The predominant evidence, however, favors the view that increased Hg0 adsorption capacities exist at higher inlet Hg0 concentrations. Such behavior is attributed to faster kinetics of Hg0 capture and an enhanced higher driving force at higher initial Hg0 inlet concentrations. Results from reviewed studies also indicated that the optimum SIC ratio and sulfur content are 2/1 and I 0-20%, respectively. Surface area has a less significant impact on Hg11

  14. Ordered mesoporous carbons obtained by a simple soft template method as sulfur immobilizers for lithium-sulfur cells.

    Science.gov (United States)

    Moreno, Noelia; Caballero, Alvaro; Hernán, Lourdes; Morales, Julián; Canales-Vázquez, Jesús

    2014-08-28

    Carbon materials with ordered mesoporous structures were synthesized using soft template methods and then activated by CO2 treatment. Sulfur was incorporated in these carbons via a simple chemical deposition method in aqueous solutions and the resulting composites were tested as electrodes in Li-S cells. The electrochemical results showed that well-ordered mesoporous carbons perform better than those with a random mesopore arrangement (wormhole-like mesoporous structure). The mesopore ordering yields a framework of well-connected empty sites that results in an enhancement of both the charge carrier mobility and the reversibility of the electrochemical reaction. Although the activation with CO2 partially destroys the mesopore arrangement, which adversely affects the electrode performance, it notably increases the surface area and the micropore content which improves the connectivity between the mesopores. The final observation was an irrelevant effect of the activation process at low current densities. However, at higher rates the activated carbon composite delivered higher capacities. The hierarchical pore structure formed by micro- and mesopores should guarantee the required fast mobility of the Li(+).

  15. Processes for preparing carbon fibers using gaseous sulfur trioxide

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Science.gov (United States)

    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.

  17. Sulfur reactions and cryptic cross-linkages to oxygen, iron, and carbon cyclin

    Science.gov (United States)

    Druschel, G.; Kafantaris, F. C. A.; Fike, D. A.; Schmitt-Kopplin, P.; Dvorski, S.; Oduro, H.

    2014-12-01

    Sulfur speciation in any setting is controlled by a complex series of redox reactions, polymerization, and complexation reactions that are affected by both biotic and abiotic processes. Additionally there are several crossroads of reactions with oxygen, carbon, and iron in which polysulfide molecules serve as a key reaction component that affects not only sulfur speciation, but the speciation, solubility, and bioavailability of these elements as well. Utilizing a combination of analytical approaches including electrochemistry, spectroscopy, mass spectrometry, and chromatography, we have started to unravel the interconnections between sulfur and other key elements, and how microorganisms may be either direct or indirect contributors to these chemical and mineralogical signatures. In microbial mats, we have observed microbial production of significant hydrogen peroxide under UV-stressed conditions. This peroxide interaction with hydrogen sulfide changes the kinetics and the pathways of abiotic sulfur reactions, potentially affecting the overall bioavailability and isotopic fractionations for specific reactions via a change in the linkage between oxygen and sulfur cycling. In systems containing significant iron, we have observed the production of an electroactive form of ferrous iron and sulfide (FeS(aq)) that is of a size that can be described between a dissolved molecular cluster and a small nanoparticle. This FeS(aq) can be a significant fraction of the dissolved iron or sulfide in a system, and is a key part of both the solubility of iron and sulfur and the pathways potentially important for pyritization reactions. In systems where we investigate the links between sulfur and carbon, laboratory and field experiments indicate a wide range of large and more reduced organic compounds are highly reactive towards polysulfide. Utilizing Fourier-transform ion cyclotron resonance mass spectrometry in conjunction with electrochemistry and chromatography, we are seeing a

  18. Adsorption of cadmium from aqueous solutions on sulfurized activated carbon prepared from nut shells.

    Science.gov (United States)

    Fouladi Tajar, Amir; Kaghazchi, Tahereh; Soleimani, Mansooreh

    2009-06-15

    Low-cost activated carbon, derived from nut shells, and its modified sample have been used as replacements for the current expensive methods of removing cadmium from aqueous solutions and waste waters. Adsorption of cadmium onto four kinds of activated carbons has been studied; prepared activated carbon (PAC), commercial activated carbon (CAC), and the sulfurized ones (SPAC & SCAC). The activated carbon has been derived, characterized, treated with sulfur and then utilized for the removal of Cd(2+). Sulfurizing agent (SO(2) gas) was successfully used in adsorbents' modification process at the ambient temperature. Samples were then characterized and tested as adsorbents of cadmium. Effect of some parameters such as contact time, initial concentration and pH were examined. With increasing pH, the adsorption of cadmium ions was increased and maximum removal, 92.4% for SPAC, was observed in pH>8.0 (C(0)=100mg/L). The H-type adsorption isotherms, obtained for the adsorbents, indicated a favorable process. Adsorption data on both prepared and commercial activated carbon, before and after sulfurization, followed both the Frendlich and Langmuir models. They were better fitted by Frendlich isotherm as compared to Langmuir. The maximum adsorption capacities were 90.09, 104.17, 126.58 and 142.86 mg/g for CAC, PAC, SCAC and SPAC, respectively. Accordingly, surface modification of activated carbons using SO(2) greatly enhanced cadmium removal. The reversibility of the process has been studied in a qualitative manner and it shows that the spent SPAC can be effectively regenerated for further use easily.

  19. Reconstructing Sulfur Cycling at Cretaceous Methane Seeps: Novel Perspectives from Carbonate-Associated Sulfate

    Science.gov (United States)

    Hancock, L. G.; Lyons, T. W.; Gill, B. C.; Formolo, M.; Shapiro, R. S.; Tripati, A.; Loyd, S. J.; Bates, S. M.

    2013-12-01

    The mechanisms of methane cycling have been studied extensively, but its full role in the chemical and organismal evolution of the ocean through time, including its closely coupled relationship to the sulfur cycle, is still largely unresolved. Modern and ancient seeps are ideal natural labs for studying coupled methane-sulfur cycles and their geochemical fingerprints as a function of the flux of methane through these systems and its availability in the ocean and marine sediments more generally. Many seep studies examine sulfur in pyrite, but pyrite formation in these settings is typically limited by the availability of reactive iron, thus only capturing the earliest diagenetic processes. In such cases, a better way to track sulfur and its role in modulating methane production and consumption is by following the pathways of dissolved sulfate, using carbonate-associated sulfate or CAS. While commonly used to track evolving seawater composition, CAS can also constrain conditions of diagenetic carbonate precipitation. This study focuses on a Cretaceous system of methane seeps, the Tepee Buttes in Colorado--which is marked by complex carbonate paragenesis--and traces sulfur, carbon, and oxygen isotopes to unravel ancient methane cycling, its relationship to sulfur metabolic pathways, and the preservational history of proxies such as CAS during burial. Burial history of this system is further unraveled through use of carbon and oxygen isotopes of various carbonate fabrics, including clumped isotope analysis. Additional geochemical measurements from the surrounding shales, such as data for redox sensitive metals, provide a context for the host setting in the Western Interior Seaway. Preliminary data suggest that paired isotopic and concentration measurements of CAS could be used to closely track spatiotemporal variation in rates of microbial sulfate reduction as coupled to anaerobic methane oxidation. These rates in both ancient and modern settings vary spatially and

  20. Removal of sulfur compounds from petroleum refinery wastewater through adsorption on modified activated carbon.

    Science.gov (United States)

    Ben Hariz, Ichrak; Al Ayni, Foued; Monser, Lotfi

    2014-01-01

    The adsorption of sulfur compounds from petroleum refinery wastewater on a chemically modified activated carbon (MAC) was investigated. The modification technique (nitric acid, hydrogen peroxide and thermal modification) enhanced the removal capacity of carbon and therefore decreases cost-effective removal of sulfide from refinery wastewater. Adsorption equilibrium and kinetics data were determined for sulfur removal from real refinery wastewater. The data were evaluated according to several adsorption isotherm and kinetics models. The Freundlich isotherm fitted well with the equilibrium data of sulfur on different adsorbents, whereas the kinetics data were best fitted by the pseudo-second-order model. Insights of sulfide removal mechanisms indicated that the sorption was controlled through the intraparticle diffusion mechanism with a significant contribution of film diffusion. The MAC adsorbent was found to have an effective removal capacity of approximately 2.5 times that of non-modified carbon. Using different MAC, sulfides were eliminated with a removal capacity of 52 mg g(-1). Therefore, MAC can be utilized as an effective and less expensive adsorbent for the reduction of sulfur in refinery wastewater.

  1. Scalable Approach To Construct Free-Standing and Flexible Carbon Networks for Lithium–Sulfur Battery

    KAUST Repository

    Li, Mengliu

    2017-02-21

    Reconstructing carbon nanomaterials (e.g., fullerene, carbon nanotubes (CNTs), and graphene) to multidimensional networks with hierarchical structure is a critical step in exploring their applications. Herein, a sacrificial template method by casting strategy is developed to prepare highly flexible and free-standing carbon film consisting of CNTs, graphene, or both. The scalable size, ultralight and binder-free characteristics, as well as the tunable process/property are promising for their large-scale applications, such as utilizing as interlayers in lithium-sulfur battery. The capability of holding polysulfides (i.e., suppressing the sulfur diffusion) for the networks made from CNTs, graphene, or their mixture is pronounced, among which CNTs are the best. The diffusion process of polysulfides can be visualized in a specially designed glass tube battery. X-ray photoelectron spectroscopy analysis of discharged electrodes was performed to characterize the species in electrodes. A detailed analysis of lithium diffusion constant, electrochemical impedance, and elementary distribution of sulfur in electrodes has been performed to further illustrate the differences of different carbon interlayers for Li-S batteries. The proposed simple and enlargeable production of carbon-based networks may facilitate their applications in battery industry even as a flexible cathode directly. The versatile and reconstructive strategy is extendable to prepare other flexible films and/or membranes for wider applications.

  2. Scalable Approach To Construct Free-Standing and Flexible Carbon Networks for Lithium-Sulfur Battery.

    Science.gov (United States)

    Li, Mengliu; Wahyudi, Wandi; Kumar, Pushpendra; Wu, Fengyu; Yang, Xiulin; Li, Henan; Li, Lain-Jong; Ming, Jun

    2017-03-08

    Reconstructing carbon nanomaterials (e.g., fullerene, carbon nanotubes (CNTs), and graphene) to multidimensional networks with hierarchical structure is a critical step in exploring their applications. Herein, a sacrificial template method by casting strategy is developed to prepare highly flexible and free-standing carbon film consisting of CNTs, graphene, or both. The scalable size, ultralight and binder-free characteristics, as well as the tunable process/property are promising for their large-scale applications, such as utilizing as interlayers in lithium-sulfur battery. The capability of holding polysulfides (i.e., suppressing the sulfur diffusion) for the networks made from CNTs, graphene, or their mixture is pronounced, among which CNTs are the best. The diffusion process of polysulfides can be visualized in a specially designed glass tube battery. X-ray photoelectron spectroscopy analysis of discharged electrodes was performed to characterize the species in electrodes. A detailed analysis of lithium diffusion constant, electrochemical impedance, and elementary distribution of sulfur in electrodes has been performed to further illustrate the differences of different carbon interlayers for Li-S batteries. The proposed simple and enlargeable production of carbon-based networks may facilitate their applications in battery industry even as a flexible cathode directly. The versatile and reconstructive strategy is extendable to prepare other flexible films and/or membranes for wider applications.

  3. From Low Sulfur to Low Carbon:The Development of International Accounting for Emission Rights%从低硫到低碳:国际排放权会计发展述评

    Institute of Scientific and Technical Information of China (English)

    王雨桐; 王瑞华

    2014-01-01

    美国的酸雨计划为世界排放权交易,包括当今最大的碳排放交易机制EU ETS开创了先河。虽然国会没有通过全国性的碳排放交易机制,但仍有不少州政府联合启动了区域性减排计划。FERC的账户统一系统是美国目前唯一的排放权会计指南,但该指南造成了对政府分配的和购买的配额的会计处理不一致。FASB希望通过EITF 03-14解决总量交易机制的排放权交易会计问题,但因种种原因被取消。此后,SFAS 153的发布是否适用于有效年份互换受到了关注,IASB曾经发布的《IFRIC 3排放权》解释公告因导致财务报告不匹配也最终被废止。FASB工作人员认为排放权是无形资产,但SEC工作人员建议不要反对存货模型,实践也表明美国公司大体上追随无形资产或存货模型,会计方法呈现差异化。排放交易机制项目缓慢进展着,准则制定者面临了一系列挑战。%The Acid Rain Program is a pioneer for the other emission right trading in the world,including the largest emission trading schemes,EU ETS.Notwithstanding the Congress failed to pass the legislation that would establish a national carbon emission trading system,other state and regional emission reduction programs have ensured carbon cap-and-trade continues to be an issue for American companies.The Uniform System of Accounts of FERC is the only accounting guidance available in the US that explicitly addresses the accounting issues on emissions allowance trading,but no value is assigned to emission allow-ances granted to companies under that.FASB laid hope on EITF 03-1 4 but the project then was removed.After SFAS 1 53 was issued,questions arose as to whether it applied to vintage year swaps.In the Europe,IFRIC 3 Emission Rights was is-sued by IASB.However,it was withdrawn due to the reporting mismatch.Despite FASB staff viewed emission allowances as intangible assets,the SEC staff advised accounting firms not

  4. Variations of sulfur and carbon isotopes in seawater during the Doushantuo stage in late Neoproterozoic

    Institute of Scientific and Technical Information of China (English)

    ZHANG Tonggang; CHU Xuelei; ZHANG Qirui; FENG Lianjun; HUO Weiguo

    2003-01-01

    Successive analyses of sulfur and carbon isotopic compositions of carbonates strata in the Doushantuo Formation in the Yangtze area were accomplished through a method of extracting trace sulfate from carbonates. Sulfur and carbon isotopic compositions of coeval seawater were estimated from the samples that show the least diagenetic alteration. A high-resolution age curve of sulfur isotopes in seawater sulfates was obtained in the Doushantuo stage, which reflects thetrend of variation in seawater sulfur isotopes after the Neoproterozoic snowball Earth event. Similar characteristics of variation in carbon isotopes were observed in the coeval carbonates. A large positive δ34S excursion over +20‰ occurs in ancient seawater sulfates in the early Doushantuo stage. Simultaneously, the δ13C values in ancient seawater carbonates exhibit a positive excursion up to10‰. The maximum δ34S and δ13C values are +46.4‰ and +6.9‰, respectively. In the middle Doushantuo stage, the range of variation in δ34S values of seawater is relatively narrow, but δ13C values are quite high. Then, δ34S values of seawater become oscillating, and the same occurs in δ13C values. Negative excursions in δ34S and δ13C values occur simultaneously at the end of the Doushantuo stage, and the minimum δ34S and δ13C values dropped down to -10.1‰ and -5.7‰, respectively. The characteristics of variations in the sulfur and carbon isotopes of ancient seawater imply strong changes in oceanic environment that became beneficial to inhabitation and propagation of organism. The organic productivity and burial rate of organic carbon once reached a quite high level during the Doushantuo stage. However, the state of environment became unstable after the global glaciation. The global climate and environment possibly were fluctuating and reiterating. The negative excursions in δ34S and δ13C values occurring at the end of the Doushantuo stage may represent a global event, which might be related to

  5. Enhanced performance of sulfur-infiltrated bimodal mesoporous carbon foam by chemical solution deposition as cathode materials for lithium sulfur batteries

    Science.gov (United States)

    Jeong, Tae-Gyung; Chun, Jinyong; Cho, Byung-Won; Lee, Jinwoo; Kim, Yong-Tae

    2017-02-01

    The porous carbon matrix is widely recognized to be a promising sulfur reservoir to improve the cycle life by suppressing the polysulfide dissolution in lithium sulfur batteries (LSB). Herein, we synthesized mesocellular carbon foam (MSUF-C) with bimodal mesopore (4 and 30 nm) and large pore volume (1.72 cm2/g) using MSUF silica as a template and employed it as both the sulfur reservoir and the conductive agent in the sulfur cathode. Sulfur was uniformly infiltrated into MSUF-C pores by a chemical solution deposition method (MSUF-C/S CSD) and the amount of sulfur loading was achieved as high as 73% thanks to the large pore volume with the CSD approach. MSUF-C/S CSD showed a high capacity (889 mAh/g after 100 cycles at 0.2 C), an improved rate capability (879 mAh/g at 1C and 420 mAh/g at 2C), and a good capacity retention with a fade rate of 0.16% per cycle over 100 cycles.

  6. One-pot self-assembly of graphene/carbon nanotube/sulfur hybrid with three dimensionally interconnected structure for lithium-sulfur batteries

    Science.gov (United States)

    Niu, Shuzhang; Lv, Wei; Zhang, Chen; Shi, Yanting; Zhao, Jianfeng; Li, Baohua; Yang, Quan-Hong; Kang, Feiyu

    2015-11-01

    A graphene/carbon nanotube (CNT)/sulfur (denoted GCS) hybrid with interconnected structure is prepared through a one-pot self-assembly approach initiated by L-ascorbic acid reduction under a mild condition. In such a solution-based assembly process, the formation of an interconnected graphene/CNT conductive network is accompanied by the uniform loading of sulfur, whose fraction is as high as of 70 wt%. The as-prepared GCS hybrid delivers an initial capacity of 1008 mAh g-1 at 0.3C and maintains 704 mAh g-1 after 100 cycles. Remarkably, at a high rate of 1.0C, the cathode shows an excellent cyclic performance with a capacity of 657 mAh g-1 after 450 ycles and the capacity decay is only 0.04% per cycle. Moreover, the superior rate performance of GCS hybrid is attributed to the conductive network formed by interconnected graphene sheets and CNT, which supply an unimpeded and continuous path for electron and Li ion transfer and accommodate the volume variation of sulfur during charge/discharge cycling. In addition, the residual functional groups on GCS can retain intimate contact of the conducting matrix with sulfur and effectively confine the diffusion of polysulfides. This study gives an eco-friendly and highly effective solution-based approach for carbon-sulfur electrode for lithium-sulfur battery.

  7. Enhanced performance of sulfur-infiltrated bimodal mesoporous carbon foam by chemical solution deposition as cathode materials for lithium sulfur batteries

    Science.gov (United States)

    Jeong, Tae-Gyung; Chun, Jinyong; Cho, Byung-Won; Lee, Jinwoo; Kim, Yong-Tae

    2017-01-01

    The porous carbon matrix is widely recognized to be a promising sulfur reservoir to improve the cycle life by suppressing the polysulfide dissolution in lithium sulfur batteries (LSB). Herein, we synthesized mesocellular carbon foam (MSUF-C) with bimodal mesopore (4 and 30 nm) and large pore volume (1.72 cm2/g) using MSUF silica as a template and employed it as both the sulfur reservoir and the conductive agent in the sulfur cathode. Sulfur was uniformly infiltrated into MSUF-C pores by a chemical solution deposition method (MSUF-C/S CSD) and the amount of sulfur loading was achieved as high as 73% thanks to the large pore volume with the CSD approach. MSUF-C/S CSD showed a high capacity (889 mAh/g after 100 cycles at 0.2 C), an improved rate capability (879 mAh/g at 1C and 420 mAh/g at 2C), and a good capacity retention with a fade rate of 0.16% per cycle over 100 cycles. PMID:28165041

  8. Effects of sulfur impregnation temperature on the properties and mercury adsorption capacities of activated carbon fibers (ACFs)

    Science.gov (United States)

    Hsi, H.-C.; Rood, M.J.; Rostam-Abadi, M.; Chen, S.; Chang, R.

    2001-01-01

    Laboratory studies were conducted to determine the role of sulfur functional groups and micropore surface area of carbon-based adsorbents on the adsorption of Hg0 from simulated coal combustion flue gases. In this study, raw activated carbon fibers that are microporous (ACF-20) were impregnated with elemental sulfur between 250 and 650 ??C. The resulting samples were saturated with respect to sulfur content. Total sulfur content of the sulfur impregnated ACF samples decreased with increasing impregnation temperatures from 250 and 500 ??C and then remained constant to 650 ??C. Results from sulfur K-edge X-ray absorption near-edge structure (S-XANES) spectroscopy showed that sulfur impregnated on the ACF samples was in both elemental and organic forms. As sulfur impregnation temperature increased, however, the relative amounts of elemental sulfur decreased with a concomitant increase in the amount of organic sulfur. Thermal analyses and mass spectrometry revealed that sulfur functional groups formed at higher impregnation temperatures were more thermally stable. In general, sulfur impregnation decreased surface area and increased equilibrium Hg0 adsorption capacity when compared to the raw ACF sample. The ACF sample treated with sulfur at 400 ??C had a surface area of only 94 m2/g compared to the raw ACF sample's surface area of 1971 m2/g, but at least 86% of this sample's surface area existed as micropores and it had the largest equilibrium Hg0adsorption capacities (2211-11343 ??g/g). Such a result indicates that 400 ??C is potentially an optimal sulfur impregnation temperature for this ACF. Sulfur impregnated on the ACF that was treated at 400 ??C was in both elemental and organic forms. Thermal analyses and CS2extraction tests suggested that elemental sulfur was the main form of sulfur affecting the Hg0 adsorption capacity. These findings indicate that both the presence of elemental sulfur on the adsorbent and a microporous structure are important properties for

  9. Effects of sulfur impregnation temperature on the properties and mercury adsorption capacities of activated carbon fibers (ACFs).

    Science.gov (United States)

    Hsi, H C; Rood, M J; Rostam-Abadi, M; Chen, S; Chang, R

    2001-07-01

    Laboratory studies were conducted to determine the role of sulfur functional groups and micropore surface area of carbon-based adsorbents on the adsorption of Hg0 from simulated coal combustion flue gases. In this study, raw activated carbon fibers that are microporous (ACF-20) were impregnated with elemental sulfur between 250 and 650 degrees C. The resulting samples were saturated with respect to sulfur content. Total sulfur content of the sulfur impregnated ACF samples decreased with increasing impregnation temperatures from 250 and 500 degrees C and then remained constant to 650 degrees C. Results from sulfur K-edge X-ray absorption near-edge structure (S-XANES) spectroscopy showed that sulfur impregnated on the ACF samples was in both elemental and organic forms. As sulfur impregnation temperature increased, however, the relative amounts of elemental sulfur decreased with a concomitant increase in the amount of organic sulfur. Thermal analyses and mass spectrometry revealed that sulfur functional groups formed at higher impregnation temperatures were more thermally stable. In general, sulfur impregnation decreased surface area and increased equilibrium Hg0 adsorption capacity when compared to the raw ACF sample. The ACF sample treated with sulfur at 400 degrees C had a surface area of only 94 m2/g compared to the raw ACF sample's surface area of 1971 m2/g, but at least 86% of this sample's surface area existed as micropores and it had the largest equilibrium Hg0 adsorption capacities (2211-11,343 micrograms/g). Such a result indicates that 400 degrees C is potentially an optimal sulfur impregnation temperature for this ACF. Sulfur impregnated on the ACF that was treated at 400 degrees C was in both elemental and organic forms. Thermal analyses and CS2 extraction tests suggested that elemental sulfur was the main form of sulfur affecting the Hg0 adsorption capacity. These findings indicate that both the presence of elemental sulfur on the adsorbent and a

  10. Nitrogen-doped MOF-derived micropores carbon as immobilizer for small sulfur molecules as a cathode for lithium sulfur batteries with excellent electrochemical performance.

    Science.gov (United States)

    Li, Zhaoqiang; Yin, Longwei

    2015-02-25

    Nitrogen-doped carbon (NDC) spheres with abundant 22 nm mesopores and 0.5 nm micropores are obtained by directly carbonization of nitrogen-contained metal organic framework (MOF) nanocrystals. Large S8 and small S2-4 molecules are successfully infiltrated into 22 nm mesopores and 0.5 nm micropores, respectively. We successfully investigate the effect of sulfur immobilization in mesopores and micropores on the electrochemical performance of lithium-sulfur (Li-S) battery based on NDC-sulfur hybrid cathodes. The large S8 molecules in 22 nm mesopores can be removed by a prolonged heat treatment, with only small molecules of S2-4 immobilized in micropores of NDC matrices. The NDC/S2-4 hybrid exhibits excellent cycling performance, high Coulombic efficiency, and good rate capability as cathode for Li-S batteries. The confinement of smaller S2-4 molecules in the micropores of NDS efficiently avoids the loss of active sulfur and formation of soluble high-order Li polysulfides. The porous carbon can buffer the volume expansion and contraction changes, promising a stable structure for cathode. Furthermore, N doping in MOF-derived carbon not only facilitates the fast charge transfer but also is helpful in building a stronger interaction between carbon and sulfur, strengthening immobilization ability of S2-4 in micropores. The NDS-sulfur hybrid cathode exhibits a reversible capacity of 936.5 mAh g(-1) at 100th cycle with a Coulombic efficiency of 100% under a current density of 335 mA g(-1). It displays a superior rate capability performance, delivering a capacity of 632 mAh g(-1) at a high rate of 5 A g(-1). This uniquely porous NDC derived from MOF nanocrystals could be applied in related high-energy storage devices.

  11. Marine Carbon-Sulfur Biogeochemical Cycles during the Steptoean Positive Carbon Isotope Excursion (SPICE) in the Jiangnan Basin, South China

    Institute of Scientific and Technical Information of China (English)

    Yang Peng; Yongbo Peng; Xianguo Lang; Haoran Ma; Kangjun Huang; Fangbing Li; Bing Shen

    2016-01-01

    ABSTRACT:Global occurrences of Steptoean Positive Carbon Isotope Excursion (SPICE) during Late Cambrian recorded a significant perturbation in marine carbon cycle, and might have had profound impacts on the biological evolution. In previous studies, SPICE has been reported from the Jiangnan slope belt in South China. To evaluate the bathymetric extent of SPICE, we investigate the limestone samples from the upper Qingxi Formation in the Shaijiang Section in the Jiangnan Basin. Our results show the positive excursions for both carbonate carbon (δ13C) and organic carbon (δ13Corg) isotopes, as well as the concurrent positive shifts in sulfur isotopes of carbonate associated sulfate (CAS, δ34SCAS) and pyrite (δ34Spyrite), unequivocally indicating the presence of SPICE in the Jiangnan Basin. A 4‰increase inδ13Ccarb of the Qingxi limestone implies the increase of the relative flux of organic carbon burial by a factor of two. Concurrent positive excursions inδ34SCAS andδ34Spyrite have been attributed to the enhanced pyrite burial in oceans with extremely low concentration and spatially heterogeneous isotopic composition of seawater sulfate. Here, we propose that the seawater sulfur isotopic heterogeneity can be generated by volatile organic sulfur compound (VOSC, such as methanethiol and dimethyl sulfide) formation in sulfidic continental margins that were widespread during SPICE. Emission of 32S-enriched VOSC in atmosphere, followed by lateral transportation and aerobic oxidation in atmosphere, and precipitation in open oceans result in a net flux of 32S from continental margins to open oceans, elevatingδ34S of seawater sulfate in continental margins. A simple box model indicates that about 35%to 75%of seawater sulfate in continental margins needs to be transported to open oceans via VOSC formation.

  12. Polyvinyl Alcohol-derived carbon nanofibers/carbon nanotubes/sulfur electrode with honeycomb-like hierarchical porous structure for the stable-capacity lithium/sulfur batteries

    Science.gov (United States)

    Deng, Nanping; Kang, Weimin; Ju, Jingge; Fan, Lanlan; Zhuang, Xupin; Ma, Xiaomin; He, Hongsheng; Zhao, Yixia; Cheng, Bowen

    2017-04-01

    The honeycomb-like hierarchical porous carbon nanofibers (PCNFs)-carbon nanotubes (CNTs)-sulfur(S) composite electrode is successfully desgined and prepared through ball-milling and heating method, in which the PCNFs are carbonized from fibers in the membrane composed of Polyvinyl Alcohol and Polytetrafluoroethylene by electro-blown spinning technology. The prepared PCNFs-CNTs-S composite are regarded as cathode for lithium-sulfur battery. The tailored porous structure and CNTs in the composite facilitate construction of a high electrical conductive pathway and store more S/polysulfides, and the dissoluble loss of intermediate S species in electrolyte can also be restrained because of acidized PVA-based porous carbon nanofibers. Meanwhile, the porous strcucture and CNTs can effectively alleviate volume changes in battery cycling process. Moreover, the presence of LiNO3 in electrolyte helps the electrochemical oxidation of Li2S and LiNO3-derived surface film effectively suppresses the migration of soluble polysulfide to the Li anode surface. Therefore, the obtained PCNFs-CNTs-S cathode exhibits excellent performance in Li-S battery with a high initial discharge capacity as high as 1302.9 mAh g-1, and super stable capacity retention with 809.1 mAh g-1 after 300 cycles at the current density of 837.5 mA g-1 (0.5 C). And the rate capability of PCNFs-CNTs-S electrode is much better than those of CNTs-S and PCNFs-S electrodes.

  13. Porous Carbon Paper as Interlayer to Stabilize the Lithium Anode for Lithium-Sulfur Battery.

    Science.gov (United States)

    Kong, Ling-Long; Zhang, Ze; Zhang, Ye-Zheng; Liu, Sheng; Li, Guo-Ran; Gao, Xue-Ping

    2016-11-23

    The lithium-sulfur (Li-S) battery is expected to be the high-energy battery system for the next generation. Nevertheless, the degradation of lithium anode in Li-S battery is the crucial obstacle for practical application. In this work, a porous carbon paper obtained from corn stalks via simple treating procedures is used as interlayer to stabilize the surface morphology of Li anode in the environment of Li-S battery. A smooth surface morphology of Li is obtained during cycling by introducing the porous carbon paper into Li-S battery. Meanwhile, the electrochemical performance of sulfur cathode is partially enhanced by alleviating the loss of soluble intermediates (polysulfides) into the electrolyte, as well as the side reaction of polysulfides with metallic lithium. The Li-S battery assembled with the interlayer exhibits a large capacity and excellent capacity retention. Therefore, the porous carbon paper as interlayer plays a bifunctional role in stabilizing the Li anode and enhancing the electrochemical performance of the sulfur cathode for constructing a stable Li-S battery.

  14. Fatty acid methyl esters, carbon nanotubes and carbon nanowalls coatings such as lubricity improvers of low sulfur diesel fuels

    Energy Technology Data Exchange (ETDEWEB)

    Cursaru, Diana Luciana; Tanasescu, Constantin [Petroleum-Gas Univ. of Ploiesti (Romania); Vizireanu, Sorin [National Institute for Laser, Plasma and Radiation Physics (Romania)

    2013-06-01

    In this study the lubricity of diesel fuel was restored by different methods, firstly by classic addition of fatty acid methyl esters or by dispersing carbon nanotubes into diesel fuels and secondly, by protecting the metallic surfaces which are in the direct contact to the low sulfur diesel fuel, by application of solid carbon nanowalls coatings synthesized by radiofrequency plasma beam deposition. The fatty acid methyl esters were prepared by transesterification of the sun flower oil in the presence of methanol. The carbon nanotubes were synthesized by CO disproportionation method and were characterized by RAMAN spectroscopy and high resolution transmission electron microscopy (TEM). The CNWs layers, before the friction tests, were examined by scanning electron microscopy (SEM), atomic force microscopy (AFM) and Raman spectroscopy, while the wear on the steel balls was investigated by optical microscopy of the HRRT apparatus and the wear track on the steel disk was investigated by SEM, AFM and profilometry. The lubricity was measured using the High Frequency Reciprocating Rig (HFRR) method. It has been found that CNWs layers exhibit a lubricating potential for the rubbed surfaces in the presence of low sulfur diesel fuels. Tribological analyses of various carbon materials revealed that the friction coefficient of carbon nanowalls is close to the values obtained for graphite. (orig.)

  15. Sulfite Oxidase Activity Is Essential for Normal Sulfur, Nitrogen and Carbon Metabolism in Tomato Leaves

    Science.gov (United States)

    Brychkova, Galina; Yarmolinsky, Dmitry; Batushansky, Albert; Grishkevich, Vladislav; Khozin-Goldberg, Inna; Fait, Aaron; Amir, Rachel; Fluhr, Robert; Sagi, Moshe

    2015-01-01

    Plant sulfite oxidase [SO; E.C.1.8.3.1] has been shown to be a key player in protecting plants against exogenous toxic sulfite. Recently we showed that SO activity is essential to cope with rising dark-induced endogenous sulfite levels in tomato plants (Lycopersicon esculentum/Solanum lycopersicum Mill. cv. Rheinlands Ruhm). Here we uncover the ramifications of SO impairment on carbon, nitrogen and sulfur (S) metabolites. Current analysis of the wild-type and SO-impaired plants revealed that under controlled conditions, the imbalanced sulfite level resulting from SO impairment conferred a metabolic shift towards elevated reduced S-compounds, namely sulfide, S-amino acids (S-AA), Co-A and acetyl-CoA, followed by non-S-AA, nitrogen and carbon metabolite enhancement, including polar lipids. Exposing plants to dark-induced carbon starvation resulted in a higher degradation of S-compounds, total AA, carbohydrates, polar lipids and total RNA in the mutant plants. Significantly, a failure to balance the carbon backbones was evident in the mutants, indicated by an increase in tricarboxylic acid cycle (TCA) cycle intermediates, whereas a decrease was shown in stressed wild-type plants. These results indicate that the role of SO is not limited to a rescue reaction under elevated sulfite, but SO is a key player in maintaining optimal carbon, nitrogen and sulfur metabolism in tomato plants. PMID:27135342

  16. Synthesis, Characterization, and Photocatalytic Properties of Sulfur- and Carbon-Codoped TiO2 Nanoparticles

    Science.gov (United States)

    Ivanov, S.; Barylyak, A.; Besaha, K.; Bund, A.; Bobitski, Y.; Wojnarowska-Nowak, R.; Yaremchuk, I.; Kus-Liśkiewicz, M.

    2016-03-01

    One-step TiO2 nanoparticle synthesis based on the interaction between thiourea and metatitanic acid is applied for sulfur and carbon anatase codoping. The synthesis of the doped TiO2 has been monitored by means of differential thermal analysis and thermogravimetric analysis (DTA-TG), which allows determining the optimal thermal conditions for the process. Electron microscopy showed micrometer-sized (5-15 μm) randomly distributed crystal aggregates, consisting of many 15-40-nm TiO2 nanoparticles. The obtained phase composition and chemical states of the doping elements are analyzed by means of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), infrared (IR) and Raman spectroscopies, and electron paramagnetic resonance (EPR). XRD displays in both samples (doped and pristine) the existence of only one crystalline phase—the tetragonal modification of TiO2—anatase. Further data assessment by means of Rietveld refinement allowed detection of a slight c lattice parameter and volume increase related to incorporation of the doping elements. XPS demonstrated the presence of carbon and sulfur as doping elements in the material. It was confirmed that carbon is in elemental form and also present in oxygen-containing compounds, which are adsorbed on the particle surface. The binding energy for sulfur electron core shell corresponds to the established data for sulfate compounds, where sulfur is in 6+ oxidation state. The synthesized S- and C-codoped TiO2 showed excellent photocatalytic performance during the degradation of organic dyes (rhodamine B, methylene blue), gas-phase oxidation of ethanol under visible light, and photocatalytic hydrogen generation from ethanol under ultraviolet light.

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

    Science.gov (United States)

    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.

  18. Porous nitrogen-doped carbon derived from silk fibroin protein encapsulating sulfur as a superior cathode material for high-performance lithium-sulfur batteries.

    Science.gov (United States)

    Zhang, Jiawei; Cai, Yurong; Zhong, Qiwei; Lai, Dongzhi; Yao, Juming

    2015-11-14

    The features of a carbon substrate are crucial for the electrochemical performance of lithium-sulfur (Li-S) batteries. Nitrogen doping of carbon materials is assumed to play an important role in sulfur immobilisation. In this study, natural silk fibroin protein is used as a precursor of nitrogen-rich carbon to fabricate a novel, porous, nitrogen-doped carbon material through facile carbonisation and activation. Porous carbon, with a reversible capacity of 815 mA h g(-1) at 0.2 C after 60 cycles, serves as the cathode material in Li-S batteries. Porous carbon retains a reversible capacity of 567 mA h g(-1), which corresponds to a capacity retention of 98% at 1 C after 200 cycles. The promising electrochemical performance of porous carbon is attributed to its mesoporous structure, high specific surface area and nitrogen doping into the carbon skeleton. This study provides a general strategy to synthesise nitrogen-doped carbons with a high specific surface area, which is crucial to improve the energy density and electrochemical performance of Li-S batteries.

  19. On the stabilization of the carbonate dianion by sulfur dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Grein, F.; Chan, J.K.; Liko, I. [New Brunswick Univ., Fredericton, NB (Canada). Dept. of Chemistry

    2010-11-15

    Dianions CO{sub 3}{sup 2}, SO{sub 4}{sup 2} and other multiply charged anions (MCA) such as PO{sub 4}{sup 3} are not electronically stable in the gas phase. As such, they decay to a lower charge anion by auto electron detachment. The stabilization of dianions and more highly charged anions by common gases was investigated in this study, with particular reference to the stabilization in the gas phase of the carbonate dianion by sulphur dioxide (SO{sub 2}) molecules. Geometries of clusters were optimized by density functional theory (DFT) methods. This paper presented the geometries of different isomers of (SO{sub 2})n and (SO{sub 2})n, for which n = 1-4. Single-point CCSD and CCSD(T) energies at the DFT-optimized geometries were also obtained for n = 1-3. For n = 1 and 2, the monoanionic clusters were adiabatically more stable than the dianionic ones. They became less stable starting at n = 3. The CCSD adiabatic electron detachment energy of the dianionic cluster changed from -0.39 eV for n = 2 to +0.20 eV for n = 3. The vertical electron detachment energy became positive at n = 2, with a CCSD value of 1.35 eV. Many of the less stable dianionic, and most of the monoionic clusters were characterized by the transfer of an oxygen atom from CO{sub 3} to SO{sub 2}. It was concluded that a minimum of 3 water molecules are needed for the stabilization of the sulfate dianion by stepwise hydration. 5 tabs., 1 fig.

  20. CO2 Adsorption by para-Nitroaniline Sulfuric Acid-Derived Porous Carbon Foam

    Directory of Open Access Journals (Sweden)

    Enrico Andreoli

    2016-12-01

    Full Text Available The expansion product from the sulfuric acid dehydration of para-nitroaniline has been characterized and studied for CO2 adsorption. The X-ray photoelectron spectroscopy (XPS characterization of the foam indicates that both N and S contents (15 and 9 wt%, respectively are comparable to those separately reported for nitrogen- or sulfur-containing porous carbon materials. The analysis of the XPS signals of C1s, O1s, N1s, and S2p reveals the presence of a large number of functional groups and chemical species. The CO2 adsorption capacity of the foam is 7.9 wt% (1.79 mmol/g at 24.5 °C and 1 atm in 30 min, while the integral molar heat of adsorption is 113.6 kJ/mol, indicative of the fact that chemical reactions characteristic of amine sorbents are observed for this type of carbon foam. The kinetics of adsorption is of pseudo-first-order with an extrapolated activation energy of 18.3 kJ/mol comparable to that of amine-modified nanocarbons. The richness in functionalities of H2SO4-expanded foams represents a valuable and further pursuable approach to porous carbons alternative to KOH-derived activated carbons.

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

    Science.gov (United States)

    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.

  2. A MnO2/Graphene Oxide/Multi-Walled Carbon Nanotubes-Sulfur Composite with Dual-Efficient Polysulfide Adsorption for Improving Lithium-Sulfur Batteries.

    Science.gov (United States)

    Li, Yong; Ye, Daixin; Liu, Wen; Shi, Bin; Guo, Rui; Zhao, Hongbin; Pei, Haijuan; Xu, Jiaqiang; Xie, Jingying

    2016-10-12

    Lithium-sulfur batteries can potentially be used as a chemical power source because of their high energy density. However, the sulfur cathode has several shortcomings, including fast capacity attenuation, poor electrochemical activity, and low Coulombic efficiency. Herein, multi-walled carbon nanotubes (CNTs), graphene oxide (GO), and manganese dioxide are introduced to the sulfur cathode. A MnO2/GO/CNTs-S composite with a unique three-dimensional (3D) architecture was synthesized by a one-pot chemical method and heat treatment approach. In this structure, the innermost CNTs work as a conducting additive and backbone to form a conducting network. The MnO2/GO nanosheets anchored on the sidewalls of CNTs have a dual-efficient absorption capability for polysulfide intermediates as well as afford adequate space for sulfur loading. The outmost nanosized sulfur particles are well-distributed on the surface of the MnO2/GO nanosheets and provide a short transmission path for Li(+) and the electrons. The sulfur content in the MnO2/GO/CNTs-S composite is as high as 80 wt %, and the as-designed MnO2/GO/CNTs-S cathode displays excellent comprehensive performance. The initial specific capacities are up to 1500, 1300, 1150, 1048, and 960 mAh g(-1) at discharging rates of 0.05, 0.1, 0.2, 0.5, and 1 C, respectively. Moreover, the composite cathode shows a good cycle performance: the specific capacity remains at 963.5 mAh g(-1) at 0.2 C after 100 cycles when the area density of sulfur is 2.8 mg cm(-2).

  3. Direct Deposition of Bamboo-Like Carbon Nanotubes on Copper Substrates by Sulfur-Assisted HFCVD

    Directory of Open Access Journals (Sweden)

    Sri Lakshmi Katar

    2008-01-01

    Full Text Available Films of bamboo-like carbon nanotubes (BCNTs were grown directly on copper substrates by sulfur-assisted hot filament chemical vapor deposition (HFCVD. The effects of substrate temperature and growth time over the BCNT structure were investigated. The films were characterized by scanning electron microscopy (SEM, Raman spectroscopy (RS, transmission electron microscopy (TEM, X-ray photoelectron spectroscopy (XPS, and electron field emission (EFE studies. SEM and Raman characterization indicate a transition from the growth of microcrystalline diamond to the growth of a dense entangled network of carbon nanotubes or fibers as the substrate temperature is increased from 400 to 900°C that is accounted for by the base growth model. TEM images show that the nanotubes have regular arrays of nanocavities. These BCNTs show good electron field emission properties as other carbon films.

  4. A Study on Reactive Ion Etching of Barium Strontium Titanate Films Using Mixtures of Argon (Ar), Carbon Tetrafluoride (CF4), and Sulfur Hexafluoride (SF6)

    Science.gov (United States)

    2014-07-01

    A Study on Reactive Ion Etching of Barium Strontium Titanate Films Using Mixtures of Argon (Ar), Carbon Tetrafluoride (CF4), and Sulfur...Etching of Barium Strontium Titanate Films Using Mixtures of Argon (Ar), Carbon Tetrafluoride (CF4), and Sulfur Hexafluoride (SF6) Samuel G...Study on Reactive Ion Etching of Barium Strontium Titanate Films Using Mixtures of Argon (Ar), Carbon Tetrafluoride (CF4), and Sulfur Hexafluoride

  5. Development of Sulfur and Carbon Tolerant Reforming Alloy Catalysts Aided by Fundamental Atomistics Insights

    Energy Technology Data Exchange (ETDEWEB)

    Suljo Linic

    2006-08-31

    Current hydrocarbon reforming catalysts suffer from rapid carbon and sulfur poisoning. Even though there is a tremendous incentive to develop more efficient catalysts, these materials are currently formulated using inefficient trial and error experimental approaches. We have utilized a novel hybrid experimental/theoretical approach, combining quantum Density Functional Theory (DFT) calculations and various state-of-the-art experimental tools, to formulate carbon tolerant reforming catalysts. We have employed DFT calculations to develop molecular insights into the elementary chemical transformations that lead to carbon poisoning of Ni catalysts. Based on the obtained molecular insights, we have identified, using DFT quantum calculation, Sn/Ni alloy as a potential carbon tolerant reforming catalyst. Sn/Ni alloy was synthesized and tested in steam reforming of methane, propane, and isooctane. We demonstrated that the alloy catalyst is carbon-tolerant under nearly stoichiometric steam-to-carbon ratios. Under these conditions, monometallic Ni is rapidly poisoned by sp2 carbon deposits. The research approach is distinguished by a few characteristics: (a) Knowledge-based, bottom-up approach, compared to the traditional trial and error approach, allows for a more efficient and systematic discovery of improved catalysts. (b) The focus is on exploring alloy materials which have been largely unexplored as potential reforming catalysts.

  6. Development of Sulfur and Carbon Tolerant Reforming Alloy Catalysts Aided Fundamental Atomistic Insights

    Energy Technology Data Exchange (ETDEWEB)

    Suljo Linic

    2008-12-31

    Current hydrocarbon reforming catalysts suffer from rapid carbon and sulfur poisoning. Even though there is a tremendous incentive to develop more efficient catalysts, these materials are currently formulated using inefficient trial and error experimental approaches. We have utilized a hybrid experimental/theoretical approach, combining quantum Density Functional Theory (DFT) calculations and various state-of-the-art experimental tools, to formulate carbon tolerant reforming catalysts. We have employed DFT calculations to develop molecular insights into the elementary chemical transformations that lead to carbon poisoning of Ni catalysts. Based on the obtained molecular insights, we have identified, using DFT quantum calculation, various Ni alloy catalysts as potential carbon tolerant reforming catalysts. The alloy catalysts were synthesized and tested in steam reforming and partial oxidation of methane, propane, and isooctane. We demonstrated that the alloy catalysts are much more carbon-tolerant than monometallic Ni catalysts under nearly stoichiometric steam-to-carbon ratios. Under these conditions, monometallic Ni is rapidly poisoned by sp2 carbon deposits. The research approach is distinguished by two characteristics: (a) knowledge-based, bottomup approach, compared to the traditional trial and error approach, allows for a more efficient and systematic discovery of improved catalysts. (b) the focus is on exploring alloy materials which have been largely unexplored as potential reforming catalysts.

  7. Nanostructured nitrogen-doped mesoporous carbon derived from polyacrylonitrile for advanced lithium sulfur batteries

    Science.gov (United States)

    Liu, Ying; Zhao, Xiaohui; Chauhan, Ghanshyam S.; Ahn, Jou-Hyeon

    2016-09-01

    Nitrogen doping in carbon matrix can effectively improve the wettability of electrolyte and increase electric conductivity of carbon by ensuring fast transfer of ions. We synthesized a series of nitrogen-doped mesoporous carbons (CPANs) via in situ polymerization of polyacrylonitrile (PAN) in SBA-15 template followed by carbonization at different temperatures. Carbonization results in the formation of ladder structure which enhances the stability of the matrix. In this study, CPAN-800, carbon matrix synthesized by the carbonization at 800 °C, was found to possess many desirable properties such as high specific surface area and pore volume, moderate nitrogen content, and highly ordered mesoporous structure. Therefore, it was used to prepare S/CPAN-800 composite as cathode material in lithium sulfur (Li-S) batteries. The S/CPAN-800 composite was proved to be an excellent material for Li-S cells which delivered a high initial discharge capacity of 1585 mAh g-1 and enhanced capacity retention of 862 mAh g-1 at 0.1 C after 100 cycles.

  8. Surface modification of Na3V2(PO4)3 by nitrogen and sulfur dual-doped carbon layer with advanced sodium storage property.

    Science.gov (United States)

    Liang, Xinghui; Ou, Xing; Zheng, Fenghua; Pan, Qichang; Xiong, Xunhui; Hu, Renzong; Yang, Chenghao; Liu, Meilin

    2017-03-27

    Nitrogen and sulfur dual-doped carbon layer wrapped Na3V2(PO4)3 nanoparticles (NVP@NSC) have been successfully fabricated by a facile solid-state method. In this hierarchical structure, the Na3V2(PO4)3 nanoparticles are well dispersed and closely coated by nitrogen and sulfur dual-doped carbon layer, constructing an effective and interconnected conducting network to reduce the internal resistance. Furthermore, the uniform coating layers alleviate the agglomeration of Na3V2(PO4)3, as well as mitigate the side reaction between electrode and electrolyte. Due to the excellent electron transfer mutually enhancing sodium diffusion for this extraordinary structure, the NVP@NSC composite delivers an impressive discharge capacity of 113.0 mAh g-1 at 1C, and shows a capacity retention of 82.1% after 5000 cycles at an ultrahigh rate of 50C, suggesting the remarkable rate capability and long cyclicity. Surprisingly, a reversible capacity of 91.1 mAh g-1 is maintained after 1000 cycles at 5C under the elevated temperature of 55°C. The approach of nitrogen and sulfur dual-doped carbon coated Na3V2(PO4)3 provides an effective and promising strategy to enhance the ultrahigh rate and ultralong life property of cathode, which can be used for large-scale commercial production in sodium ion batteries.

  9. Effects of Electrospun Carbon Nanofibers’ Interlayers on High-Performance Lithium–Sulfur Batteries

    Directory of Open Access Journals (Sweden)

    Tianji Gao

    2017-03-01

    Full Text Available Two different interlayers were introduced in lithium–sulfur batteries to improve the cycling stability with sulfur loading as high as 80% of total mass of cathode. Melamine was recommended as a nitrogen-rich (N-rich amine component to synthesize a modified polyacrylic acid (MPAA. The electrospun MPAA was carbonized into N-rich carbon nanofibers, which were used as cathode interlayers, while carbon nanofibers from PAA without melamine was used as an anode interlayer. At the rate of 0.1 C, the initial discharge capacity with two interlayers was 983 mAh g−1, and faded down to 651 mAh g−1 after 100 cycles with the coulombic efficiency of 95.4%. At the rate of 1 C, the discharge capacity was kept to 380 mAh g−1 after 600 cycles with a coulombic efficiency of 98.8%. It apparently demonstrated that the cathode interlayer is extremely effective at shutting down the migration of polysulfide ions. The anode interlayer induced the lithium ions to form uniform lithium metal deposits confined on the fiber surface and in the bulk to strengthen the cycling stability of the lithium metal anode.

  10. Enhancing the adsorption of vapor-phase mercury chloride with an innovative composite sulfur-impregnated activated carbon.

    Science.gov (United States)

    Ie, Iau-Ren; Chen, Wei-Chin; Yuan, Chung-Shin; Hung, Chung-Hsuang; Lin, Yuan-Chung; Tsai, Hsieh-Hung; Jen, Yi-Shiu

    2012-05-30

    Mercury chloride (HgCl(2)) is the major mercury derivate emitted from municipal solid waste incinerators, which has high risk to the environment and human health. This study investigated the adsorption of vapor-phase HgCl(2) with an innovative composite sulfurized activated carbon (AC), which was derived from the pyrolysis, activation, and sulfurization of waste tires. The composite sulfur-impregnation process impregnated activated carbon with aqueous-phase sodium sulfide (Na(2)S) and followed with vapor-phase elemental sulfur (S(0)). Thermogravimetric analysis (TGA) was applied to investigate the adsorptive capacity of vapor-phase HgCl(2) using the composite sulfurized AC. The operating parameters included the types of composite sulfurized AC, the adsorption temperature, and the influent HgCl(2) concentration. Experimental results indicated that the sulfur-impregnation process could increase the sulfur content of the sulfurized AC, but decreased its specific surface area. This study further revealed that the composite sulfurized AC impregnated with aqueous-phase Na(2)S and followed with vapor-phase S(0) (Na(2)S+S(0) AC) had much higher saturated adsorptive capacity of HgCl(2) than AC impregnated in the reverse sequence (S(0)+Na(2)S AC). A maximum saturated adsorptive capacity of HgCl(2) up to 5236 μg-HgCl(2)/g-C was observed for the composite Na(2)S+S(0) AC, which was approximately 2.00 and 3.17 times higher than those for the single Na(2)S and S(0) ACs, respectively.

  11. Sulfur, carbon, hydrogen, and oxygen isotope geochemistry of the Idaho cobalt belt

    Science.gov (United States)

    Johnson, Craig A.; Bookstrom, Arthur A.; Slack, John F.

    2012-01-01

    Cobalt-copper ± gold deposits of the Idaho cobalt belt, including the deposits of the Blackbird district, have been analyzed for their sulfur, carbon, hydrogen, and oxygen isotope compositions to improve the understanding of ore formation. Previous genetic hypotheses have ranged widely, linking the ores to the sedimentary or diagenetic history of the host Mesoproterozoic sedimentary rocks, to Mesoproterozoic or Cretaceous magmatism, or to metamorphic shearing. The δ34S values are nearly uniform throughout the Blackbird dis- trict, with a mean value for cobaltite (CoAsS, the main cobalt mineral) of 8.0 ± 0.4‰ (n = 19). The data suggest that (1) sulfur was derived at least partly from sedimentary sources, (2) redox reactions involving sulfur were probably unimportant for ore deposition, and (3) the sulfur was probably transported to sites of ore for- mation as H2S. Hydrogen and oxygen isotope compositions of the ore-forming fluid, which are calculated from analyses of biotite-rich wall rocks and tourmaline, do not uniquely identify the source of the fluid; plausible sources include formation waters, metamorphic waters, and mixtures of magmatic and isotopically heavy meteoric waters. The calculated compositions are a poor match for the modified seawaters that form vol- canogenic massive sulfide (VMS) deposits. Carbon and oxygen isotope compositions of siderite, a mineral that is widespread, although sparse, at Blackbird, suggest formation from mixtures of sedimentary organic carbon and magmatic-metamorphic carbon. The isotopic compositions of calcite in alkaline dike rocks of uncertain age are consistent with a magmatic origin. Several lines of evidence suggest that siderite postdated the emplacement of cobalt and copper, so its significance for the ore-forming event is uncertain. From the stable isotope perspective, the mineral deposits of the Idaho cobalt belt contrast with typical VMS and sedimentary exhalative deposits. They show characteristics of deposit

  12. Sulfur-infiltrated graphene-backboned mesoporous carbon nanosheets with a conductive polymer coating for long-life lithium-sulfur batteries

    Science.gov (United States)

    Dong, Yanfeng; Liu, Shaohong; Wang, Zhiyu; Liu, Yang; Zhao, Zongbin; Qiu, Jieshan

    2015-04-01

    Sandwich-type, two-dimensional hybrid nanosheets were fabricated by the infiltration of nanosized sulfur into graphene-backboned mesoporous carbon with a PPy nanocoating. They exhibit a high reversible capacity for as long as 400 cycles with an ultra slow decay rate of 0.05% per cycle at the high rate of 1-3 C due to the efficient immobilization of polysulfides.Sandwich-type, two-dimensional hybrid nanosheets were fabricated by the infiltration of nanosized sulfur into graphene-backboned mesoporous carbon with a PPy nanocoating. They exhibit a high reversible capacity for as long as 400 cycles with an ultra slow decay rate of 0.05% per cycle at the high rate of 1-3 C due to the efficient immobilization of polysulfides. Electronic supplementary information (ESI) available: Experimental details, BET, SEM, XPS and more electrochemical data. See DOI: 10.1039/c5nr01015b

  13. Carbon-sulfur bond-forming reaction catalysed by the radical SAM enzyme HydE

    Science.gov (United States)

    Rohac, Roman; Amara, Patricia; Benjdia, Alhosna; Martin, Lydie; Ruffié, Pauline; Favier, Adrien; Berteau, Olivier; Mouesca, Jean-Marie; Fontecilla-Camps, Juan C.; Nicolet, Yvain

    2016-05-01

    Carbon-sulfur bond formation at aliphatic positions is a challenging reaction that is performed efficiently by radical S-adenosyl-L-methionine (SAM) enzymes. Here we report that 1,3-thiazolidines can act as ligands and substrates for the radical SAM enzyme HydE, which is involved in the assembly of the active site of [FeFe]-hydrogenase. Using X-ray crystallography, in vitro assays and NMR spectroscopy we identified a radical-based reaction mechanism that is best described as the formation of a C-centred radical that concomitantly attacks the sulfur atom of a thioether. To the best of our knowledge, this is the first example of a radical SAM enzyme that reacts directly on a sulfur atom instead of abstracting a hydrogen atom. Using theoretical calculations based on our high-resolution structures we followed the evolution of the electronic structure from SAM through to the formation of S-adenosyl-L-cysteine. Our results suggest that, at least in this case, the widely proposed and highly reactive 5‧-deoxyadenosyl radical species that triggers the reaction in radical SAM enzymes is not an isolable intermediate.

  14. Adsorption of sulfur dioxide on ammonia-treated activated carbon fibers

    Science.gov (United States)

    Mangun, C.L.; DeBarr, J.A.; Economy, J.

    2001-01-01

    A series of activated carbon fibers (ACFs) and ammonia-treated ACFs prepared from phenolic fiber precursors have been studied to elucidate the role of pore size, pore volume, and pore surface chemistry on adsorption of sulfur dioxide and its catalytic conversion to sulfuric acid. As expected, the incorporation of basic functional groups into the ACFs was shown as an effective method for increasing adsorption of sulfur dioxide. The adsorption capacity for dry SO2 did not follow specific trends; however the adsorption energies calculated from the DR equation were found to increase linearly with nitrogen content for each series of ACFs. Much higher adsorption capacities were achieved for SO2 in the presence of oxygen and water due to its catalytic conversion to H2SO4. The dominant factor for increasing adsorption of SO2 from simulated flue gas for each series of fibers studied was the weight percent of basic nitrogen groups present. In addition, the adsorption energies calculated for dry SO2 were shown to be linearly related to the adsorption capacity of H2SO4 from this flue gas for all fibers. It was shown that optimization of this parameter along with the pore volume results in higher adsorption capacities for removal of SO2 from flue gases. ?? 2001 Elsevier Science Ltd. All rights reserved.

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

    Science.gov (United States)

    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.

  16. Sulfur in foraminiferal calcite as a potential proxy for seawater carbonate ion concentration

    Science.gov (United States)

    van Dijk, I.; de Nooijer, L. J.; Boer, W.; Reichart, G.-J.

    2017-07-01

    Sulfur (S) incorporation in foraminiferal shells is hypothesized to change with carbonate ion concentration [CO32-], due to substitution of sulfate for carbonate ions in the calcite crystal lattice. Hence S/Ca values of foraminiferal carbonate shells are expected to reflect sea water carbonate chemistry. To generate a proxy calibration linking the incorporation of S into foraminiferal calcite to carbonate chemistry, we cultured juvenile clones of the larger benthic species Amphistegina gibbosa and Sorites marginalis over a 350-1200 ppm range of pCO2 values, corresponding to a range in [CO32-] of 93 to 211 μmol/kg. We also investigated the potential effect of salinity on S incorporation by culturing juvenile Amphistegina lessonii over a large salinity gradient (25-45). Results show S/CaCALCITE is not impacted by salinity, but increases with increasing pCO2 (and thus decreasing [CO32-] and pH), indicating S incorporation may be used as a proxy for [CO32-]. Higher S incorporation in high-Mg species S. marginalis suggests a superimposed biomineralization effect on the incorporation of S. Microprobe imaging reveals co-occurring banding of Mg and S in Amphistegina lessonii, which is in line with a strong biological control and might explain higher S incorporation in high Mg species. Provided a species-specific calibration is available, foraminiferal S/Ca values might add a valuable new tool for reconstructing past ocean carbonate chemistry.

  17. Absorption mechanism of carbon-nanotube paper- titanium dioxide as a multifunctional barrier material for lithium-sulfur batteries

    Institute of Scientific and Technical Information of China (English)

    Guiyin Xu[1; Jiaren Yuan[1; Xinyong Tao[2; Bing Ding[1; Hui Dou[1; Xiaohong Yan[1,3; Yang xiao[1; Xiaogang Zhang[1

    2015-01-01

    Lithium-sulfur batteries attract much interest as energy storage devices for their low cost, high specific capacity, and energy density. However, the insulating properties of sulfur and high solubility of lithium polysulfides decrease the utilization of active materials by the battery resulting in poor cycling performance. Herein, we design a multifunctional carbon-nanotube paper/titanium-dioxide barrier which effectively reduces active material loss and suppresses the diffusion of lithium polysulfides to the anode, thereby improving the cycling stability of lithium-sulfur batteries. Using this barrier, an activated carbon/sulfur cathode with 70% sulfur content delivers stable cycling performance and high Coulombic efficiency (-99%) over 250 cycles at a current rate of 0.5 C. The improved electrochemical performance is attributed to the synergistic effects of the carbon nanotube paper and titanium dioxide, involving the physical barrier, chemical adsorption from the binding formation of Ti-S and S-O, and other interactions unique to the titanium dioxide and sulfur species.

  18. Designing and Validating Ternary Pd Alloys for Optimum Sulfur/Carbon Resistance in Hydrogen Separation and Carbon Capture Membrane Systems Using High-Throughput Combinatorial Methods

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, Amanda [Pall Corporation, Port Washington, NY (United States); Zhao, Hongbin [Pall Corporation, Port Washington, NY (United States); Hopkins, Scott [Pall Corporation, Port Washington, NY (United States)

    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.

  19. Designing and Validating Ternary Pd Alloys for Optimum Sulfur/Carbon Resistance in Hydrogen Separation and Carbon Capture Membrane Systems Using High-Throughput Combinatorial Methods

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, Amanda; Zhao, Hongbin; Hopkins, Scott

    2014-09-30

    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.

  20. Carbon and Sulfur Isotopic Signatures of Ancient Life and Environment at the Microbial Scale: Neoarchean Shales and Carbonates

    Science.gov (United States)

    Williford, K. H.; Ushikubo, T.; Lepot, K.; Kitajima, K.; Hallmann, C.; Spicuzza, M. J.; Kozdon, R.; Eigenbrode, J. L.; Summons, R. E.; Valley, J. W.

    2015-01-01

    An approach to coordinated, spatially resolved, in situ carbon isotope analysis of organic matter and carbonate minerals, and sulfur three- and four-isotope analysis of pyrite with an unprecedented combination of spatial resolution, precision, and accuracy is described. Organic matter and pyrite from eleven rock samples of Neoarchean drill core express nearly the entire range of delta(sup 13)C, delta(sup 34)S, Delta(sup 33)S, and Delta(sup 36)S known from the geologic record, commonly in correlation with morphology, mineralogy, and elemental composition. A new analytical approach (including a set of organic calibration standards) to account for a strong correlation between H/C and instrumental bias in SIMS delta(sup 13)C measurement of organic matter is identified. Small (2-3 microns) organic domains in carbonate matrices are analyzed with sub-permil accuracy and precision. Separate 20- to 50-micron domains of kerogen in a single approx. 0.5 cu cm sample of the approx. 2.7 Ga Tumbiana Formation have delta(sup 13)C = -52.3 +/- 0.1per mille and -34.4 +/- 0.1per mille, likely preserving distinct signatures of methanotrophy and photoautotrophy. Pyrobitumen in the approx. 2.6 Ga Jeerinah Formation and the approx. 2.5 Ga Mount McRae Shale is systematically 13C-enriched relative to co-occurring kerogen, and associations with uraniferous mineral grains suggest radiolytic alteration. A large range in sulfur isotopic compositions (including higher Delta(sup 33)S and more extreme spatial gradients in Delta(sup 33)S and Delta(sup 36)S than any previously reported) are observed in correlation with morphology and associated mineralogy. Changing systematics of delta(sup 34)S, Delta(sup 33)S, and Delta(sup 36)S, previously investigated at the millimeter to centimeter scale using bulk analysis, are shown to occur at the micrometer scale of individual pyrite grains. These results support the emerging view that the dampened signature of mass-independent sulfur isotope fractionation

  1. Carbon and sulfur isotopic signatures of ancient life and environment at the microbial scale: Neoarchean shales and carbonates.

    Science.gov (United States)

    Williford, K H; Ushikubo, T; Lepot, K; Kitajima, K; Hallmann, C; Spicuzza, M J; Kozdon, R; Eigenbrode, J L; Summons, R E; Valley, J W

    2016-03-01

    An approach to coordinated, spatially resolved, in situ carbon isotope analysis of organic matter and carbonate minerals, and sulfur three- and four-isotope analysis of pyrite with an unprecedented combination of spatial resolution, precision, and accuracy is described. Organic matter and pyrite from eleven rock samples of Neoarchean drill core express nearly the entire range of δ(13) C, δ(34) S, Δ(33) S, and Δ(36) S known from the geologic record, commonly in correlation with morphology, mineralogy, and elemental composition. A new analytical approach (including a set of organic calibration standards) to account for a strong correlation between H/C and instrumental bias in SIMS δ(13) C measurement of organic matter is identified. Small (2-3 μm) organic domains in carbonate matrices are analyzed with sub-permil accuracy and precision. Separate 20- to 50-μm domains of kerogen in a single ~0.5 cm(3) sample of the ~2.7 Ga Tumbiana Formation have δ(13) C = -52.3 ± 0.1‰ and -34.4 ± 0.1‰, likely preserving distinct signatures of methanotrophy and photoautotrophy. Pyrobitumen in the ~2.6 Ga Jeerinah Formation and the ~2.5 Ga Mount McRae Shale is systematically (13) C-enriched relative to co-occurring kerogen, and associations with uraniferous mineral grains suggest radiolytic alteration. A large range in sulfur isotopic compositions (including higher Δ(33) S and more extreme spatial gradients in Δ(33) S and Δ(36) S than any previously reported) are observed in correlation with morphology and associated mineralogy. Changing systematics of δ(34) S, Δ(33) S, and Δ(36) S, previously investigated at the millimeter to centimeter scale using bulk analysis, are shown to occur at the micrometer scale of individual pyrite grains. These results support the emerging view that the dampened signature of mass-independent sulfur isotope fractionation (S-MIF) associated with the Mesoarchean continued into the early Neoarchean, and that the connections

  2. Carbon and sulfur relationships in Devonian shales from the Appalachian Basin as an indicator of environment of deposition.

    Science.gov (United States)

    Leventhal, J.S.

    1987-01-01

    Interprets the covariance of organic carbon and sulfide sulfur in core samples. This covariance results from the catabolism of organic carbon and concomitant reduction of sulfate by sulfate reducing bacteria to form aqueous sulfide which reacts with iron. Defines a central basin area that was the most anoxic-sulfidic (euxinic). This part of the basin is similar to the area of thickest, most organic carbon-rich sediments and has the greatest source-rock potential for petroleum. -from Author

  3. Surface oxidized mesoporous carbons derived from porous silicon as dual polysulfide confinement and anchoring cathodes in lithium sulfur batteries

    Science.gov (United States)

    Carter, Rachel; Ejorh, Dennis; Share, Keith; Cohn, Adam P.; Douglas, Anna; Muralidharan, Nitin; Tovar, Trenton M.; Pint, Cary L.

    2016-10-01

    Despite widespread focus on porous carbons for lithium-sulfur battery cathode materials, electrode design to preserve mass-specific performance and sustained extended cycling stability remains a challenge. Here, we demonstrate electrochemically etched porous silicon as a sacrificial template to produce a new class of functional mesoporous carbons optimized for dual chemical and physical confinement of soluble polysulfides in lithium-sulfur battery cathodes. Melt infiltration loading of sulfur at 60 wt% enables initial discharge capacity of 1350 mAh/gsulfur at rates of 0.1 C - approaching theoretical capacity of 1675 mAh/gsulfur. Cycling performance measured at 0.2 C indicates 81% capacity retention measured over 100 cycles with 830 mAh/gsulfur capacity. Unlike other carbons, this template combines structural properties necessary for sulfur containment and polysulfide confinement to achieve high specific capacity, but also boasts surface-bound oxygen-containing functional groups that are able to chemically anchor the soluble Li2Sn species on the interior of the mesoporous carbon to sustain cycling performance. In turn, this elucidates a scalable and competitive material framework that is capable, without the addition of additional membranes or inactive anchoring materials, of providing the simultaneous anchoring and confinement effects necessary to overcome performance limitations in lithium sulfur batteries.

  4. Biomass Waste Inspired Highly Porous Carbon for High Performance Lithium/Sulfur Batteries.

    Science.gov (United States)

    Zhao, Yan; Ren, Jun; Tan, Taizhe; Babaa, Moulay-Rachid; Bakenov, Zhumabay; Liu, Ning; Zhang, Yongguang

    2017-09-06

    The synthesis of highly porous carbon (HPC) materials from poplar catkin by KOH chemical activation and hydrothermal carbonization as a conductive additive to a lithium-sulfur cathode is reported. Elemental sulfur was composited with as-prepared HPC through a melt diffusion method to form a S/HPC nanocomposite. Structure and morphology characterization revealed a hierarchically sponge-like structure of HPC with high pore volume (0.62 cm³∙g (−1) ) and large specific surface area (1261.7 m²∙g (−1) ). When tested in Li/S batteries, the resulting compound demonstrated excellent cycling stability, delivering a second-specific capacity of 1154 mAh∙g (−1) as well as presenting 74% retention of value after 100 cycles at 0.1 C. Therefore, the porous structure of HPC plays an important role in enhancing electrochemical properties, which provides conditions for effective charge transfer and effective trapping of soluble polysulfide intermediates, and remarkably improves the electrochemical performance of S/HPC composite cathodes.

  5. Carbonized cellulose paper as an effective interlayer in lithium-sulfur batteries

    Science.gov (United States)

    Li, Shiqi; Ren, Guofeng; Hoque, Md Nadim Ferdous; Dong, Zhihua; Warzywoda, Juliusz; Fan, Zhaoyang

    2017-02-01

    One of the several challenging problems hampering lithium-sulfur (Li-S) battery development is the so-called shuttling effect of the highly soluble intermediates (Li2S8-Li2S6). Using an interlayer inserted between the sulfur cathode and the separator to capture and trap these soluble intermediates has been found effective in diminishing this effect. Previously, most reported interlayer membranes were synthesized in a complex and expensive process, and might not be suitable for practical cheap batteries. Herein, a facile method is reported to pyrolyze the commonly used cellulose filter paper into highly flexible and conductive carbon fiber paper. When used as an interlayer, such a carbon paper can improve the cell capacity by several folds through trapping the soluble polysulfides. The enhanced electronic conductivity of the cathode, due to the interlayer, also significantly improves the cell rate performance. In addition, it was demonstrated that such an interlayer can also effectively mitigate the self-discharge problem of the Li-S batteries. This study indicates that the cost-effective pyrolyzed cellulose paper has potential as interlayer for practical Li-S batteries.

  6. Biomolecule-assisted synthesis of carbon nitride and sulfur-doped carbon nitride heterojunction nanosheets: An efficient heterojunction photocatalyst for photoelectrochemical applications.

    Science.gov (United States)

    Tao, Hua Bing; Yang, Hong Bin; Chen, Jiazang; Miao, Jianwei; Liu, Bin

    2014-01-01

    A biomolecule-assisted pyrolysis method has been developed to synthesize sulfur-doped graphitic carbon nitride (CNS) nanosheets. During the synthesis, sulfur could be introduced as a dopant into the lattice of carbon nitride (CN). Sulfur doping changed the texture as well as relative band positions of CN. By growing CN on preformed sulfur-doped CN nanosheets, composite CN/CNS heterojunction nanosheets were constructed, which significantly enhanced the photoelectrochemical performance as compared with various control counterparts including CN, CNS and physically mixed CN and CNS (CN+CNS). The enhanced photoelectrochemical performance of CN/CNS heterojunction nanosheets could be ascribed to the efficient separation of photoexcited charge carriers across the heterojunction interface. The strategy of designing and preparing CN/CNS heterojunction photocatalysts in this work can open up new directions for the construction of all CN-based heterojunction photocatalysts.

  7. Removals of aqueous sulfur dioxide and hydrogen sulfide using CeO2-NiAl-LDHs coating activated carbon and its mix with carbon nano-tubes

    KAUST Repository

    Li, Jing

    2015-07-01

    Ce-doped NiAl/layered double hydroxide was coated at activated carbon by urea hydrolysis method (CeO2-NiAl-LDHs/AC) in one pot, which was characterized by X-ray diffraction, infrared spectra, field emission scanning electron microscope and electrochemical techniques. CeO2-NiAl-LDHs/AC shows good uptake for aqueous sulfur dioxide (483.09mg/g) and hydrogen sulfide (181.15mg/g), respectively at 25°C. Meanwhile, the electrochemical removals of aqueous sulfur dioxide and hydrogen sulfide were respectively investigated at the mix of CeO2-NiAl-LDHs/AC and carbon nano-tubes modified homed paraffin-impregnated electrode. Both sulfur dioxide and hydrogen sulfide could be effectively oxidized to sulfuric acid at 1.0V in alkaline aqueous solution. © 2015 Elsevier B.V.

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

    Science.gov (United States)

    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.

  9. Morphology control of ordered mesoporous carbons for high capacity lithium sulfur batteries

    Energy Technology Data Exchange (ETDEWEB)

    Schuster, Joerg David

    2011-06-07

    The focus of this thesis concerns the morphology control of ordered mesoporous carbon (OMC) materials. Ordered mesoporous carbons with diverse morphologies, that are thin films, fibers - embedded in anodic alumina membranes and free-standing - or spherical nanoparticles, have been successfully prepared by soft-templating procedures. The mechanisms of structure formation and processing were investigated with in-situ SAXS measurements and their application in high capacity lithium-sulfur batteries was successfully tested in cooperation with Guang He and Linda Nazar from the University of Waterloo in Canada. The Li-S batteries receive increasing attention due to their high theoretical energy density which is 3 to 5 times higher than from lithium-ion batteries. For this type of battery the specific pore volume is crucial for the content of the active component (sulfur) in the cathode and therefore correlates with the capacity and gravimetric energy density of the battery. At first, mesoporous thin films with 2D-hexagonal structure were obtained through organic-organic self-assembly of a preformed oligomeric resol precursor and the triblock copolymer template Pluronic P123. The formation of a condensed-wall material through thermopolymerization of the precursor oligomers resulted in mesostructured phenolic resin films. Subsequent decomposition of the surfactant and partial carbonization were achieved through thermal treatment in inert atmosphere. The films were crack-free with tunable homogenous thicknesses, and showed either 2D-hexagonal or lamellar mesostructure. An additional, yet unknown 3D-mesostructure was also found. In the second part, cubic and circular hexagonal mesoporous carbon phases in the confined environment of tubular anodic alumina membrane (AAM) pores were obtained by self-assembly of the mentioned resol precursor and the triblock copolymer templates Pluronic F127 or P123, respectively. Casting and solvent-evaporation were also followed by

  10. Recycling of water, carbon, and sulfur during subduction of serpentinites: A stable isotope study of Cerro del Almirez, Spain

    Science.gov (United States)

    Alt, Jeffrey C.; Garrido, Carlos J.; Shanks, Wayne C.; Turchyn, Alexandra; Padrón-Navarta, José Alberto; López Sánchez-Vizcaíno, Vicente; Gómez Pugnaire, María Teresa; Marchesi, Claudio

    2012-01-01

    We use the concentrations and isotope compositions of water, carbon, and sulfur in serpentinites and their dehydration products to trace the cycling of volatiles during subduction. Antigorite serpentinites from the Cerro del Almirez complex, Spain, contain 9–12 wt.% H2O and 910 ± 730 ppm sulfur, and have bulk δ18O values of 8.6 ± 0.4‰, δD = − 54 ± 5‰, and δ34S = 5.0‰, consistent with serpentinization at temperatures of ~ 200 °C by seawater hydrothermal fluids in a seafloor setting. The serpentinites were dehydrated to chlorite–harzburgite (olivine + orthopyroxene + chlorite) at 700 °C and 1.6–1.9 GPa during subduction metamorphism, resulting in loss of water, and sulfur. The chlorite–harzburgites contain 5.7 ± 1.9 wt.% H2O, and have bulk δ18O = 8.0 ± 0.9‰, and δD = − 77 ± 11‰. The rocks contain 650 ± 620 ppm sulfur having δ34S = 1.2‰. Dehydration of serpentinite resulted in loss of 5 wt.% H2O having δ18O = 8–10‰ and δD = − 27 to − 65‰, and loss of 260 ppm sulfur as sulfate, having δ34S = 14.5‰. The contents and δ13C of total carbon in the two rock types overlap, with a broad trend of decreasing carbon contents and δ13C from ~ 1300 to 200 ppm and − 9.6 to − 20.2‰. This reflects mixing between reduced carbon in the rocks (210 ppm, δ13C ≈ − 26‰) and seawater-derived carbonate (δ13C ≈ − 1‰). Our results indicate: 1) Serpentinized oceanic peridotites carry significant amounts of isotopically fractionated water, carbon and sulfur into subduction zones; 2) Subduction of serpentinites to high P and T results in loss of water, and sulfur, which can induce melting and contribute to 18O, D, and 34S enrichments and oxidation of the sub-arc mantle wedge; and 3) Isotopically fractionated water, carbon, and sulfur in serpentinite dehydration products are recycled deeper into the mantle where they can contribute to isotope heterogeneities and may be significant for volatile budgets of the deep Earth.

  11. Influence of Heat Treatments on the Corrosion Resistance of Medium -Carbon Steel using Sulfuric Spring Water

    Directory of Open Access Journals (Sweden)

    Ikhlas Basheer

    2013-04-01

    Full Text Available The corrosion is one of the important problems that may be occur to the parts of machinery and equipment after manufactured and when used as a result of exposure to corrosive media. Plain-carbon steel is considered as one of the most common minerals used in industrial applications. Some of heat treatments can have direct effect on the corrosion rate of steel by building up galvanic corrosion cells between its microscopic phases. Therefore, to adopt one of kinds of the plain-carbon steel and the most commonly used in industry to be study subject, that is medium carbon steel and took samples of this steel has been treated thermally in three methods which the normalising, annealing, and hardening .The corrosive media used in the research is Sulfuric Spring, it contains many chemical compounds to show its influence on the corrosion of steel. The weight loss method is used to determine corrosion rate and to compare between the results obtained, show that the greatest corrosion resistance of the annealed steel and the corrosion resistance of the hardened steel is the lowest while the corrosion  resistance of the normalised steel is in-between them.         Calcium carbonate was formed on the metal surface which acts as an isolating layer which decrease corrosion rate with time

  12. Removal of hydrogen sulfide and sulfur dioxide by carbons impregnated with triethylenediamine.

    Science.gov (United States)

    Wu, Li-Chun; Chang, Tsu-Hua; Chung, Ying-Chien

    2007-12-01

    Activated carbon (AC) adsorption has long been considered to be a readily available technology for providing protection against exposure to acutely toxic gases. However, ACs without chemical impregnation have proven to be much less efficient than impregnated ACs in terms of gas removal. The impregnated ACs in current use are usually modified with metalloid impregnation agents (ASC-carbons; copper, chromium, or silver) to simultaneously enhance the chemical and physical properties of the ACs in removing specific poisonous gases. These metalloid agents, however, can cause acute poisoning to both humans and the environment, thereby necessitating the search for organic impregnation agents that present a much lower risk. The aim of the study reported here was to assess AC or ASC-carbon impregnated with triethylenediamine (TEDA) in terms of its adsorption capability for simulated hydrogen sulfide (H2S) and sulfur dioxide (SO2) gases. The investigation was undergone in a properly designed laboratory-scale and industrial fume hood evaluation. Using the system reported here, we obtained a significant adsorption: the removal capability for H2S and SO2 was 375 and 229 mg/g-C, respectively. BET measurements, element analysis, scanning electron microscopy, and energy dispersive spectrometry identified the removal mechanism for TEDA-impregnated AC to be both chemical and physical adsorption. Chemical adsorption and oxidation were the primary means by which TEDA-impregnated ASC-carbons removed the simulated gases.

  13. Adsorption/oxidation of sulfur-containing gases on nitrogen-doped activated carbon

    Directory of Open Access Journals (Sweden)

    Liu Qiang

    2016-01-01

    Full Text Available Coconut shell-based activated carbon (CAC was used for the removal of methyl mercaptan (MM. CAC was modified by urea impregnation and calcined at 450°C and 950°C. The desulfurization activity was determined in a fixed bed reactor under room temperature. The results showed that the methyl mercaptan adsorption/oxidation capacity of modified carbon caicined at 950°C is more than 3 times the capacity of original samples. On the other hand, the modified carbon caicined at 950°C also has a high capacity for the simultaneous adsorption/oxidation of methyl mercaptan and hydrogen sulfide.The introduce of basic nitrogen groups siginificantly increases the desulfurization since it can facilitate the electron transfer process between sulfur and oxygen. The structure and chemical properties are characterized using Boehm titration, N2 adsorption-desorption method, thermal analysis and elemental analysis. The results showed that the major oxidation products were dimethyl disulfide and methanesulfonic acid which adsorbed in the activated carbon.

  14. Conductive Carbon Network inside a Sulfur-Impregnated Carbon Sponge: A Bioinspired High-Performance Cathode for Li-S Battery.

    Science.gov (United States)

    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.

  15. Preparation of mesohollow and microporous carbon nanofiber and its application in cathode material for lithium–sulfur batteries

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Yuanhe; Gao, Mingxia, E-mail: gaomx@zju.edu.cn; Li, Xiang; Liu, Yongfeng; Pan, Hongge, E-mail: hgpan@zju.edu.cn

    2014-09-01

    Highlights: • Mesohollow and microporous carbon fibers were prepared via electrospinning and carbonization. • Sulfur (S) incorporated into the porous fibers by thermal heating in 60 wt.%, forming composite. • S fills fully in the micropores and partially in the mesohollows of the carbon fibers. • The composite shows high capacity and capacity retention as cathode material for Li–S batteries. • Mesohollow and microporous structure is effective in improving the property of S cathode. - Abstract: Mesohollow and microporous carbon nanofibers (MhMpCFs) were prepared by a coaxial electrospinning with polyacrylonitrile (PAN) and polymethylmethacrylate (PMMA) as outer and inner spinning solutions followed by a carbonization. The carbon fibers were thermal treated with sublimed sulfur to form S/MhMpCFs composite, which was used as cathode material for lithium–sulfur batteries. Electrochemical study shows that the S/MhMpCFs cathode material provides a maximum capacity of 815 mA h/g after several cycles of activation, and the capacity retains 715 mA h/g after 70 cycles, corresponding to a retention of 88%. The electrochemical property of the S/MhMpCFs composite is much superior than the S-incorporated solid carbon fibers prepared from electrospinning of single PAN. The mechanism of the enhanced electrochemical property of the S/MhMpCFs composite is discussed.

  16. Graphene Sandwiched by Sulfur-Confined Mesoporous Carbon Nanosheets: A Kinetically Stable Cathode for Li-S Batteries.

    Science.gov (United States)

    Xin, Sen; You, Ya; Li, Hui-Qin; Zhou, Weidong; Li, Yutao; Xue, Leigang; Cong, Huai-Ping

    2016-12-14

    The practical use of lithium-sulfur batteries for the next-generation energy storage, especially the automobiles, was hindered by low electronic conductivity of sulfur and the resulting poor rate capabilities. Here, we report a sulfur-carbon composite by confining S into a graphene sandwiched in mesoporous carbon nanosheets with a two-dimensional ultrathin morphology, suitable mesopore size and large pore volume, and excellent electronic conductivity. Serving as cathode material for a Li-S battery, the elaborately designed S/C composite leads to "kinetically stable" transmissions of Li ions and electrons, triggering a stable electrochemistry and a record-breaking rate performance. In this way, the S/C composite has been proved a promising cathode material for high-rate Li-S batteries targeted at automobile storage.

  17. Ternary Porous Sulfur/Dual-Carbon Architectures for Lithium/Sulfur Batteries Obtained Continuously and on a Large Scale via an Industry-Oriented Spray-Pyrolysis/Sublimation Method.

    Science.gov (United States)

    Liang, Xin; Kaiser, Mohammad Rejaul; Konstantinov, Konstantin; Tandiono, Richard; Wang, Zhaoxiang; Chen, Chunhua; Liu, Hua-Kun; Dou, Shi-Xue; Wang, Jiazhao

    2016-09-28

    Ternary composites with porous sulfur/dual-carbon architectures have been synthesized by a single-step spray-pyrolysis/sublimation technique, which is an industry-oriented method that features continuous fabrication of products with highly developed porous structures without the need for any further treatments. A double suspension of commercial sulfur and carbon scaffolding particles was dispersed in ethanol/water solution and sprayed at 180 °C using a spray pyrolysis system. In the resultant composites, the sulfur particles were subjected to an ultrashort sublimation process, leading to the development of a highly porous surface, and were meanwhile coated with amorphous carbon, obtained through the pyrolysis of the ethanol, which acts as an adhesive interface to bind together the porous sulfur with the scaffolding carbon particles, to form a ternary composite architecture. This material has an effective conducting-carbon/sulfur-based matrix and interconnected open pores to reduce the diffusion paths of lithium ions, buffer the sulfur volumetric expansion, and absorb electrolyte and polysulfides. Because of the unique chemistry and the structure, the composites show stable cycling performance for 200 cycles and good rate capability of 520 mAh g(-1) at 2 C. This advanced spray-pyrolysis/sublimation method is easy to scale up and shows great potential for commercialization of lithium/sulfur batteries.

  18. Effect of coal tar pitch modified by sulfur as a binder on the mechanical and tribological properties of bronze-impregnated carbon-matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Yang Huijun [School of Physics and Nuclear Energy Engineering, Beijing University of Aeronautics and Astronautics, No. 37, Xue Yuan Road, Hai Dian District, Beijing 100191 (China); Luo Ruiying, E-mail: ryluo@buaa.edu.cn [School of Physics and Nuclear Energy Engineering, Beijing University of Aeronautics and Astronautics, No. 37, Xue Yuan Road, Hai Dian District, Beijing 100191 (China)

    2011-03-15

    Research highlights: {yields} Sulfur addition increased the softening point and carbon yield of coal tar pitch. {yields} The mechanical properties of the composites reached a maximum at 7 wt. % of sulfur. {yields} The friction coefficient rose monotonously with increasing the content of sulfur. {yields} The wear rate of the composites reached a minimum at 7 wt. % of sulfur. {yields} The wear mechanism of composites was adhesive wear, abrasive wear and oxidative wear. - Abstract: Bronze-impregnated carbon-matrix composites were prepared through compression molding, carbonization and impregnation. The mechanism of sulfuration was studied, and the effect of coal tar pitch modified by sulfur as a binder on the mechanical and tribological properties of composites was investigated by varying the content of sulfur. The results showed that the sulfur addition increased the softening point, carbon yield and C/H atomic ratio of coal tar pitch but decreased the toluene solubility and quinoline solubility due to the dehydrogenating polymerization of pitch molecules. The micro-hardness, bending strength and compressive strength of the composites were enhanced by increasing the mass percentage of sulfur and reached a maximum of 160 HV, 132.82 MPa and 293 MPa at 7 wt. % of sulfur, respectively. However, both the hardness and strength of the composites decreased as the content of sulfur increased beyond 7 wt. %. The friction coefficient value of composites increased monotonously, but the wear rate decreased with increasing sulfur content; subsequently, the wear rate reached a minimum of 3.045 x 10{sup -7} mm{sup 3}/Nm at 7 wt. % of sulfur and then ascended. The wear mechanisms of the composites were adhesive wear, abrasive wear and oxidative wear. However, adhesive wear and oxidative wear occurred slightly for the composites with the binder modified by sulfur.

  19. Preparation of nitrogen and sulfur co-doped ordered mesoporous carbon for enhanced microwave absorption performance

    Science.gov (United States)

    Yuan, Xiaoyan; Xue, Xingkun; Ma, Hailong; Guo, Shouwu; Cheng, Laifei

    2017-09-01

    Ordered mesoporous carbon nanomaterials (OMCs) co-doped with homogeneous nitrogen and sulfur heteroatoms were prepared by nanocasting with the pyrrole oligomer catalyzed by sulfuric acid as a precursor and ordered mesoporous silica SBA-15 as a hard-template. By multi-technique approach utilization, it was demonstrated that the N and S co-doped OMCs possessed high ordered mesoporous structures, large surface areas and homogeneous distribution of heteroatoms. As a microwave absorber, the as-prepared materials exhibited a minimum reflection loss (RL) of -32.5 dB at the thickness of 2.5 mm and an absorption bandwidth of 3.2 GHz (RL < -10 dB) in X-band (8.2-12.4 GHz). The good microwave absorption performance was mainly originated from the high electrical conductivity induced by the high surface activity and special structures. And microwave energy can be effectively attenuated through multiple reflections and absorptions in complex conductive network. The design strategy in this work would contribute to the production of a lightweight absorber, presenting a strong absorbency and a wide bandwidth in microwave frequency.

  20. Biogeochemical cycles of carbon, sulfur, and free oxygen in a microbial mat

    Science.gov (United States)

    Canfield, Donald E.; Des Marais, David J.

    1993-01-01

    Complete budgets for carbon and oxygen have been constructed for cyanobacterial mats dominated by Microcoleus chthonoplastes from the evaporating ponds of a salt works. We infer from the data the various sinks for O2 as well as the sources of carbon for primary production. Although seasonal variability exists, a major percentage of the O2 produced during the day did not diffuse out of the mat but was used within the mat to oxidize both organic carbon and the sulfide produced by sulfate reduction. At night, most of the O2 that diffused into the mat was used to oxidize sulfide, with O2 respiration of minor importance. During the day, the internal mat processes of sulfate reduction and O2 respiration generated as much or more inorganic carbon (DIC) for primary production as diffusion into the mat. Oxygenic photosynthesis was the most important process of carbon fixation. At night, the DIC lost from the mat was mostly from sulfate reduction. Elemental fluxes across the mat/brine interface indicated that carbon with an oxidation state of greater than zero was taken up by the mat during the day and liberated from the mat at night. Overall, carbon with an average oxidation state of near zero accumulated in the mat. Both carbon fixation and carbon oxidation rates varied with temperature by a similar amount.

  1. Biogeochemical cycles of carbon, sulfur, and free oxygen in a microbial mat

    Science.gov (United States)

    Canfield, Donald E.; Des Marais, David J.

    1993-01-01

    Complete budgets for carbon and oxygen have been constructed for cyanobacterial mats dominated by Microcoleus chthonoplastes from the evaporating ponds of a salt works. We infer from the data the various sinks for O2 as well as the sources of carbon for primary production. Although seasonal variability exists, a major percentage of the O2 produced during the day did not diffuse out of the mat but was used within the mat to oxidize both organic carbon and the sulfide produced by sulfate reduction. At night, most of the O2 that diffused into the mat was used to oxidize sulfide, with O2 respiration of minor importance. During the day, the internal mat processes of sulfate reduction and O2 respiration generated as much or more inorganic carbon (DIC) for primary production as diffusion into the mat. Oxygenic photosynthesis was the most important process of carbon fixation. At night, the DIC lost from the mat was mostly from sulfate reduction. Elemental fluxes across the mat/brine interface indicated that carbon with an oxidation state of greater than zero was taken up by the mat during the day and liberated from the mat at night. Overall, carbon with an average oxidation state of near zero accumulated in the mat. Both carbon fixation and carbon oxidation rates varied with temperature by a similar amount.

  2. Morphology control of ordered mesoporous carbons for high capacity lithium sulfur batteries

    Energy Technology Data Exchange (ETDEWEB)

    Schuster, Joerg David

    2011-06-07

    The focus of this thesis concerns the morphology control of ordered mesoporous carbon (OMC) materials. Ordered mesoporous carbons with diverse morphologies, that are thin films, fibers - embedded in anodic alumina membranes and free-standing - or spherical nanoparticles, have been successfully prepared by soft-templating procedures. The mechanisms of structure formation and processing were investigated with in-situ SAXS measurements and their application in high capacity lithium-sulfur batteries was successfully tested in cooperation with Guang He and Linda Nazar from the University of Waterloo in Canada. The Li-S batteries receive increasing attention due to their high theoretical energy density which is 3 to 5 times higher than from lithium-ion batteries. For this type of battery the specific pore volume is crucial for the content of the active component (sulfur) in the cathode and therefore correlates with the capacity and gravimetric energy density of the battery. At first, mesoporous thin films with 2D-hexagonal structure were obtained through organic-organic self-assembly of a preformed oligomeric resol precursor and the triblock copolymer template Pluronic P123. The formation of a condensed-wall material through thermopolymerization of the precursor oligomers resulted in mesostructured phenolic resin films. Subsequent decomposition of the surfactant and partial carbonization were achieved through thermal treatment in inert atmosphere. The films were crack-free with tunable homogenous thicknesses, and showed either 2D-hexagonal or lamellar mesostructure. An additional, yet unknown 3D-mesostructure was also found. In the second part, cubic and circular hexagonal mesoporous carbon phases in the confined environment of tubular anodic alumina membrane (AAM) pores were obtained by self-assembly of the mentioned resol precursor and the triblock copolymer templates Pluronic F127 or P123, respectively. Casting and solvent-evaporation were also followed by

  3. Organic carbon-sulfur relationships in sediment cores from the western and eastern continental margins of India

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, P.S.; Mascarenhas, A.; Paropkari, A.L.; Rao, Ch.M.

    deposition and terrigenous influx on organic carbon-sulfur relationship. The results indicate that the cores consist of two stratigraphic units: an upper unit of Holocene age and a lower unit of Late Pleistocene age. The upper unit of WM1 and WM2 has C...

  4. Characterization of carbon, sulfur and volatile compounds in nuclear fuel U{sub 3}SI{sub 2}-AL

    Energy Technology Data Exchange (ETDEWEB)

    Moura, Sergio C.; Coelho, Felipe P.; Bustillos, Jose O.V., E-mail: ovega@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (CNEN/IPEN-SP), Sao Paulo, SP (Brazil)

    2013-07-01

    The scope of this work is to describe the characterization of Carbon, Sulfur and Volatile Compounds in nuclear fuel U{sub 3}Si{sub 2}-Al used in a research pool type reactor with 5 KW power capacities, located in Sao Paulo, Brazil. This reactor produces a large range of radioisotopes for radiopharmaceutical needed in Brazil nuclear medicine. The fabrication of the fuel U{sub 3}Si{sub 2}-Al plate is the key of the whole assembly production and its quality directly affects the safety and reliability of the fuel assembly performance. For this reason, it is very necessary to analyze the Carbon, Sulfur and Volatile Compounds to avoid damage in the fuel plate. The Carbon and Sulfur are characterized by the method of radio frequency furnace gas extraction system coupled with infrared cell detector. The Volatile Compounds are characterized by the method of heat gas extraction coupled with gravimetric technique. These methods are recommended by American Society for Testing Materials ASTM for nuclear materials. The average carbon and sulfur analyzed are 30 μg/g and 3 μg/g, respectively. The average for Volatile Compounds is 40 μg/g. These results represent satisfactory performance of the fuel inside the nuclear reactor. A statistical laboratory program has been set to validate the data generated in the nuclear fuel material to specify any agreement with the recommended ASTM methods. (author)

  5. Biogeochemical Cycles of Carbon and Sulfur on Early Earth (and on Mars?)

    Science.gov (United States)

    DesMarais, D. J.

    2004-01-01

    The physical and chemical interactions between the atmosphere, hydrosphere, geosphere and biosphere can be examined for elements such as carbon (C) and sulfur (S) that have played central roles for both life and the environment. The compounds of C are highly important, not only as organic matter, but also as atmospheric greenhouse gases, pH buffers in seawater, oxidation-reduction buffers virtually everywhere, and key magmatic constituents affecting plutonism and volcanism. S assumes important roles as an oxidation-reduction partner with C and Fe in biological systems, as a key constituent in magmas and volcanic gases, and as a major influence upon pH in certain environments. These multiple roles of C and S interact across a network of elemental reservoirs interconnected by physical, chemical and biological processes. These networks are termed biogeochemical C and S cycles.

  6. Effect of sulfur on enhancing nitrogen-doping and magnetic properties of carbon nanotubes

    Science.gov (United States)

    Cui, Tongxiang; Lv, Ruitao; Huang, Zheng-Hong; Kang, Feiyu; Wang, Kunlin; Wu, Dehai

    2011-12-01

    Sulfur (S) is introduced as an additive in the growth atmosphere of carbon nanotubes (CNTs) in the range of 940-1020°C. CNT products with distorted sidewalls can be obtained by S-assisted growth. Moreover, many fascinating CNT structures can also be found in samples grown with S addition, such as bamboo-like CNTs, twisted CNTs, arborization-like CNTs, and bead-like CNTs. Compared with CNTs grown without S, more nitrogen-doping content is achieved in CNTs with S addition, which is beneficial for the properties and applications of nitrogen-doped CNTs. In addition, S can also enhance the encapsulation of ferromagnetic materials and thus improve the soft magnetic properties of CNTs, which is favorable to the applications of CNTs in the electromagnetic wave-absorbing and magnetic data storage areas.

  7. Effect of sulfur on enhancing nitrogen-doping and magnetic properties of carbon nanotubes

    Directory of Open Access Journals (Sweden)

    Wang Kunlin

    2011-01-01

    Full Text Available Abstract Sulfur (S is introduced as an additive in the growth atmosphere of carbon nanotubes (CNTs in the range of 940-1020°C. CNT products with distorted sidewalls can be obtained by S-assisted growth. Moreover, many fascinating CNT structures can also be found in samples grown with S addition, such as bamboo-like CNTs, twisted CNTs, arborization-like CNTs, and bead-like CNTs. Compared with CNTs grown without S, more nitrogen-doping content is achieved in CNTs with S addition, which is beneficial for the properties and applications of nitrogen-doped CNTs. In addition, S can also enhance the encapsulation of ferromagnetic materials and thus improve the soft magnetic properties of CNTs, which is favorable to the applications of CNTs in the electromagnetic wave-absorbing and magnetic data storage areas.

  8. Hydrophilicity-controlled ordered mesoporous carbon for lithium-sulfur batteries.

    Science.gov (United States)

    Bae, Suyeon; Jin, Xing; Park, Gwi Ok; Kim, Ji Man

    2014-12-01

    Ordered mesoporous carbon (OMC) materials were synthesized from a mesoporous silica KIT-6 (3-D cubic la3d meso-structure) as the hard-template via a nano-replication method. Hydrophilic and hydrophobic OMC materials were prepared using different carbon precursors including sucrose (suc-OMC) and phenanthrene (phe-OMC) at different carbonization temperatures of 700 degrees C and 1100 degrees C, respectively. The OMC materials thus obtained exhibit high surface areas, uniform mesopore sizes and highly ordered meso-structure. To investigate the hydrophilicity effect of OMC materials on the performance of lithium-sulfur battery, we prepared the samples having different ratios of the suc-OMC to phe-OMC, which were 100:0, 75:25, 50:50, 25:75 and 0:100. As a result, the mixed OMC materials (with ratios of 75:25, 50:50 and 25:75) exhibited better cycle performances, compared to those of the suc-OMC and phe-OMC.

  9. Salt Marsh sediment 15N/13C "Push-Pull" assays reveal coupled sulfur, nitrogen, and carbon cycling

    Science.gov (United States)

    Thomas, S. M.; Tucker, J.; Thomas, F.; Sievert, S. M.; Cardon, Z. G.; Giblin, A. E.

    2016-12-01

    Salt marshes are extraordinarily productive ecosystems found in estuaries worldwide, hosting intensive sulfur, nitrogen, and carbon cycling. Although it has been hypothesized that in this environment sulfur oxidation may be important for energy flow, there is little direct data. At the heart of these hypothesized interactions are sulfur oxidizing microbes. Sulfur oxidizers can catalyze sulfide (re-)oxidation with nitrate as the electron acceptor under anaerobic conditions, producing ammonium (via DNRA) or dinitrogen gas (via denitrification). The form of sulfur present in marsh systems influences whether autotrophic or heterotrophic processes transform nitrate either to dinitrogen gas or ammonium through DNRA. To examine the fate of nitrate and interactions with sulfur, we conducted a series of "push-pull" experiments in marsh sediment at the Plum Island Ecosystems Long-Term Ecological Research site in Massachusetts. Porewater was extracted anoxically and amended with isotopically labeled nitrate (15N) and bicarbonate (13C). Porewater was pumped back into the sediment and then withdrawn at intervals of several hours. Dissolved inorganic nitrogen, sulfur, and carbon were measured as well as isotopes of nitrogen gas and ammonium. These push-pull experiments were conducted at several times during the growing season, to coincide with salt marsh grass initial growth (May), maximum growth (July), flowering (August), and senescence (October). Porewater sulfides were very low to non-detectable in May (time of initial plant growth) and increased to a maximum of 3 mM in October (time of plant senescence). Combined rates of denitrification and DNRA also varied seasonally: rates were higher in May (0.16 - 17.5 nmoles N/cm3/hr) and much lower in October (0 - 0.03 nmoles N/cm3/hr). Interestingly, DNRA rates were always higher than denitrification rates, often by an order of magnitude or more.

  10. Hypogenic origin of Provalata Cave, Republic of Macedonia: a distinct case of successive thermal carbonic and sulfuric acid speleogenesis

    Directory of Open Access Journals (Sweden)

    Marjan Temovski

    2013-09-01

    Full Text Available Provalata Cave (Republic of Macedonia is a small but remarkable hypogenic cave, developed in Cambrian marbles by successive thermal carbonic and sulfuric acid speleogenesis. The cave has a thick partly corroded calcite crust, abundant gypsum deposits, with cupolas, ceiling and wall channels, feeders and replacement pockets as some of the most characteristic morphological features. Distribution of morphology and deposits suggest a hypogenic origin in two distinct speleogenetic phases: the first by thermal CO2 rich waters, the second by sulfuric acid dissolution, which were separated by complete infilling of cave passages with pyroclastic-derived clays. In the first phase of speleogenesis, cave passages were formed by dissolution along fractures due to cooling of rising carbonated thermal waters. These phreatic morphologies were later covered with a thick calcite crust deposited in a shallow phreatic environment. In Early Pleistocene the cave was completely filled with clays due to deposition of pyroclastic rocks in a lacustrine environment in the nearby Mariovo Basin. Mariovo Lake sediments were later incised by the Buturica River, which cut down into Cambrian marbles, creating its superimposed valley. Incision lowered the water table and allowed removal of the clay deposits in Provalata Cave. The second phase of speleogenesis started after introduction of H2S associated with rising thermal waters. Oxidation produced sulfuric acid, which rapidly dissolved first calcite crust, then marble host rock. Condensation-corrosion by sulfuric vapors replaced carbonate rock with gypsum producing replacement pockets as well as second generation of pockets and cupolas. The contact of sulfuric acid with the clay deposits formed alunite, jarosite, and natroalunite. 40Ar/39Ar dating gave maximum ages of 1.6 Ma (alunite and 1.46 Ma (jarosite for this last stage of speleogenesis, thus making it the second 40Ar/39Ar dating of a sulfuric cave in Europe (after Kraush

  11. Establishing the fair allocation of international aviation carbon emission rights

    Directory of Open Access Journals (Sweden)

    Feng-Cai Zhao

    2014-09-01

    Full Text Available To identify potentially unfair use of international aviation carbon emission rights in different countries, this paper presents a carbon Lorenz curve and Gini coefficient, constructed on the basis of historical cumulative international aviation CO2 emissions per capita. The study follows a methodology adapted from the research into fair income allocation. The results of these calculations show that there has been vast unfairness surrounding international aviation carbon emissions in the past, and that this unfairness has been partially hidden by a delay in accumulative start dates. A solution to this problem, allowing fair allocation of carbon emissions, is the key to building a mechanism for the reduction of global international aviation emissions. This study proposes a fair method for allocating emission rights, based on a responsibility-capacity index. Taking a goal of carbon-neutral growth by 2020 as an example, the degree of carbon emission reduction expected from different countries by 2021 is calculated using the proposed method.

  12. Biogeochemical cycles of carbon, sulfur, and free oxygen in a microbial mat

    Science.gov (United States)

    Canfield, Donald E.; Des Marais, David J.

    1993-08-01

    Complete budgets for carbon and oxygen have been constructed for cyanobacterial mats dominated by Microcoleus chthonoplastes from the evaporating ponds of a salt works located in Guerrero Negro, Baja California Sur, Mexico. Included in the budget are measured rates of O 2 production, sulfate reduction, and elemental exchange across the mat/brine interface, day and night, at various temperatures and times of the year. We infer from this data the various sinks for O 2, as well as the sources of carbon for primary production. To summarize, although seasonal variability exists, a major percentage of the O 2 produced during the day did not diffuse out of the mat but was used within the mat to oxidize both organic carbon and the sulfide produced by sulfate reduction. At night, most of the O 2 that diffused into the mat was used to oxidize sulfide, with O 2 respiration of minor importance. During the day, the internal mat processes of sulfate reduction and O 2 respiration generated as much or more inorganic carbon (DIC) for primary production as diffusion into the mat. Also, oxygenic photosynthesis was the most important process of carbon fixation, although anoxygenic photosynthesis may have been important at low light levels during some times of the year. At night, the DIC lost from the mat was mostly from sulfate reduction. Elemental fluxes across the mat/brine interface indicated that carbon with an oxidation state of greater than zero was taken up by the mat during the day and liberated from the mat at night. Overall, carbon with an average oxidation state of near zero accumulated in the mat. Both carbon fixation and carbon oxidation rates varied with temperature by a similar amount. These mats are thus closely coupled systems where rapid rates of photosynthesis both require and fuel rapid rates of heterotrophic carbon oxidation.

  13. The carbon and sulfur cycles and atmospheric oxygen from middle Permian to middle Triassic

    Science.gov (United States)

    Berner, Robert A.

    2005-07-01

    The results of a theoretical isotope mass balance model are presented for the time dependence of burial and weathering-plus-degassing fluxes within the combined long-term carbon and sulfur cycles. Averaged data for oceanic δ 13C and δ 34S were entered for every million years from 270 to 240 Ma (middle Permian to middle Triassic) to study general trends across the Permian-Triassic boundary. Results show a drop in the rate of global organic matter burial during the late Permian and a predominance of low values during the early-to-middle Triassic. This overall decrease with time is ascribed mainly to epochs of conversion of high biomass forests to low biomass herbaceous vegetation resulting in a decrease in the production of terrestrially derived organic debris. Additional contributions to lessened terrestrial carbon burial were increased aridity and a drop in sea level during the late Permian which led to smaller areas of low-lying coastal wetlands suitable for coal and peat deposition. Mirroring the drop in organic matter deposition was an increase in the burial of sedimentary pyrite, and a dramatic increase in the calculated global mean ratio of pyrite-S to organic-C. High S/C values resulted from an increase of deposition in marine euxinic basins combined with a decrease in the burial of low-pyrite associated terrestrial organic matter. The prediction of increased oceanic anoxia during the late Permian and early Triassic agrees with independent studies of the composition of sedimentary rocks. Weathering plus burial fluxes for organic carbon and pyrite sulfur were used to calculate changes in atmospheric oxygen. The striking result is a continuous drop in O 2 concentration from ˜30% to ˜13% over a twenty million year period. This drop was brought about mainly by a decrease in the burial of terrestrially derived organic matter. but with a possible contribution from the weathering of older organic matter on land. It must have exerted a considerable influence on

  14. Sulfur and carbon geochemistry of the Santa Elena peridotites: Comparing oceanic and continental processes during peridotite alteration

    Science.gov (United States)

    Schwarzenbach, Esther M.; Gill, Benjamin C.; Gazel, Esteban; Madrigal, Pilar

    2016-05-01

    Ultramafic rocks exposed on the continent serve as a window into oceanic and continental processes of water-peridotite interaction, so called serpentinization. In both environments there are active carbon and sulfur cycles that contain abiogenic and biogenic processes, which are eventually imprinted in the geochemical signatures of the basement rocks and the calcite and magnesite deposits associated with fluids that issue from these systems. Here, we present the carbon and sulfur geochemistry of ultramafic rocks and carbonate deposits from the Santa Elena ophiolite in Costa Rica. The aim of this study is to leverage the geochemistry of the ultramafic sequence and associated deposits to distinguish between processes that were dominant during ocean floor alteration and those dominant during low-temperature, continental water-peridotite interaction. The peridotites are variably serpentinized with total sulfur concentrations up to 877 ppm that is typically dominated by sulfide over sulfate. With the exception of one sample the ultramafic rocks are characterized by positive δ34Ssulfide (up to + 23.1‰) and δ34Ssulfate values (up to + 35.0‰). Carbon contents in the peridotites are low and are isotopically distinct from typical oceanic serpentinites. In particular, δ13C of the inorganic carbon suggests that the carbon is not derived from seawater, but rather the product of the interaction of meteoric water with the ultramafic rocks. In contrast, the sulfur isotope data from sulfide minerals in the peridotites preserve evidence for interaction with a hydrothermal fluid. Specifically, they indicate closed system abiogenic sulfate reduction suggesting that oceanic serpentinization occurred with limited input of seawater. Overall, the geochemical signatures preserve evidence for both oceanic and continental water-rock interaction with the majority of carbon (and possibly sulfate) being incorporated during continental water-rock interaction. Furthermore, there is

  15. Synthesis of graphitic ordered mesoporous carbon with cubic symmetry and its application in lithium-sulfur batteries

    Science.gov (United States)

    Kim, Min-Seop; Jeong, Jinhoo; Cho, Won Il; Kim, Woong

    2016-03-01

    The lithium-sulfur (Li-S) battery faces a couple of major problems in practical applications, including the low conductivity of sulfur and the dissolution of polysulfides. A cathode constructed using a composite of sulfur and ordered mesoporous carbon (OMC) is a promising solution to both problems, as OMCs can have high conductivity and a complex pore structure to trap polysulfides. In this work, we demonstrate that performance of the Li-S battery can be significantly enhanced by using an OMC with a high degree of graphitization and a pore network with cubic symmetry. This graphitic OMC (GOMC) can be produced in a single step using iron phthalocyanine precursor and a silica template with cubic Ia3d symmetry. The GOMC-sulfur (GOMC/S) composite is 175% higher in electrical conductivity compared to the typical OMC-sulfur (OMC/S) composite. In addition, the three-dimensional pore network in GOMC prevents the migration of dissolved polysulfides. These characteristics of GOMC contribute to the improved rate capability and cyclability of the corresponding Li-S battery.

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

    Science.gov (United States)

    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.

  17. Zinc and sulfur isotope variation in sphalerite from carbonate-hosted zinc deposits, Cantabria, Spain

    Science.gov (United States)

    Pašava, Jan; Tornos, Fernando; Chrastný, Vladislav

    2014-10-01

    We studied zinc and sulfur isotopes and the chemical composition of sphalerite samples from Picos de Europa (Aliva mine) and sphalerite and hydrozincite samples from La Florida mine, two carbonate-hosted Mississippi Valley-type (MVT) deposits located in northern Spain; despite being close, they are hosted in carbonatic rocks of different ages, Lower Carboniferous and Lower Cretaceous, respectively. The two generations of sphalerite at Picos de Europa show different δ66Zn values (stage 1 sphalerite +0.24 per mil and stage 2 sphalerite from -0.75 to +0.08 per mil). Both generations also differ in the sulfur isotope composition (stage 1 has δ34S = +6.6 and stage 2 has δ34S = -0.9 to +2.9 per mil) and the chemical composition (stage 1 sphalerite, compared to stage 2 sphalerite, is significantly enriched in Pb, As, Mn, Sb, slightly enriched in Ag, Ni, and Cu and depleted in Co, Ga, Tl, Te, Ge, and Sn). We suggest that Zn isotope fractionation was controlled predominantly by pH and T changes. High Zn isotope values reflect rapid precipitation of sphalerite from higher-temperature acidic fluids that carried Zn mostly as chloride species after interaction with carbonate rocks while lower Zn isotope values most likely resulted from a longer precipitation process from fluid at higher pH and decreasing T that carried dominantly Zn sulfide species. At La Florida, sphalerite samples show light 66Zn-depleted signatures with δ66Zn values from -0.80 to -0.01 per mil (mostly between -0.80 and -0.24 per mil) and δ34S values from +10.7 to +15.7 per mil without any relationship between the δ66Zn and δ34S values. Here, the variation in Zn isotope values is interpreted as related to mixing of fluids from two reservoirs. The Zn was carried by a single deep-seated and higher T (~250-320 °C) fluid, and precipitation took place after mixing with a connate S-rich fluid in a system with mH2S > mZn2+ as a result of change in pH, T, and Zn predominant species. The light δ66Zn

  18. Construction of tubular polypyrrole-wrapped biomass-derived carbon nanospheres as cathode materials for lithium-sulfur batteries

    Science.gov (United States)

    Yu, Qiuhong; Lu, Yang; Peng, Tao; Hou, Xiaoyi; Luo, Rongjie; Wang, Yange; Yan, Hailong; Liu, Xianming; Kim, Jang-Kyo; Luo, Yongsong

    2017-03-01

    A promising hybrid material composed of tubular polypyrrole (T-PPy)-wrapped monodisperse biomass-derived carbon nanospheres (BCSs) was first synthesized successfully via a simple hydrothermal approach by using watermelon juice as the carbon source, and further used as an anchoring object for sulfur (S) of lithium-sulfur (Li-S) batteries. The use of BCSs with hydrophilic nature as a framework could provide large interface areas between the active materials and electrolyte, and improve the dispersion of T-PPy, which could help in the active material utilization. As a result, BCS@T-PPy/S as a cathode material exhibited a high capacity of 1143.6 mA h g-1 and delivered a stable capacity up to 685.8 mA h g-1 after 500 cycles at 0.5 C, demonstrating its promising application for rechargeable Li-S batteries.

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

    Science.gov (United States)

    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

  20. Atmospheric measurements of carbonyl sulfide, dimethyl sulfide, and carbon disulfide using the electron capture sulfur detector

    Science.gov (United States)

    Johnson, James E.; Bates, Timothy S.

    1993-01-01

    Measurements of atmospheric dimethyl sulfide (DMS), carbonyl sulfide (COS), and carbon disulfide (CS2) were conducted over the Atlantic Ocean on board the NASA Electra aircraft during the Chemical Instrumentation Test and Evaluation (CITE 3) project using the electron capture sulfur detector (ECD-S). The system employed cryogenic preconcentration of air samples, gas chromatographic separation, catalytic fluorination, and electron capture detection. Samples collected for DMS analysis were scrubbed of oxidants with NaOH impregnated glass fiber filters to preconcentration. The detection limits (DL) of the system for COS, DMS, and CS2 were 5, 5, and 2 ppt, respectively. COS concentrations ranged from 404 to 603 ppt with a mean of 489 ppt for measurements over the North Atlantic Ocean (31 deg N to 41 deg N), and from 395 to 437 ppt with a mean of 419 ppt for measurements over the Tropical Atlantic Ocean (11 deg S to 2 deg N). DMS concentrations in the lower marine boundary layer, below 600-m altitude, ranged from below DL to 150 ppt from flights over the North Atlantic, and from 9 to 104 ppt over the Tropical Atlantic. CS2 concentrations ranged from below DL to 29 ppt over the North Atlantic. Almost all CS2 measurements over the Tropical Atlantic were below DL.

  1. Kinetically Enhanced Electrochemical Redox of Polysulfides on Polymeric Carbon Nitrides for Improved Lithium-Sulfur Batteries.

    Science.gov (United States)

    Liang, Ji; Yin, Lichang; Tang, Xiaonan; Yang, Huicong; Yan, Wensheng; Song, Li; Cheng, Hui-Ming; Li, Feng

    2016-09-28

    The kinetics and stability of the redox of lithium polysulfides (LiPSs) fundamentally determine the overall performance of lithium-sulfur (Li-S) batteries. Inspired by theoretical predictions, we herein validated the existence of a strong electrostatic affinity between polymeric carbon nitride (p-C3N4) and LiPSs, that can not only stabilize the redox cycling of LiPSs, but also enhance their redox kinetics. As a result, utilization of p-C3N4 in a Li-S battery has brought much improved performance in the aspects of high capacity and low capacity fading over prolonged cycling. Especially upon the application of p-C3N4, the kinetic barrier of the LiPS redox reactions has been significantly reduced, which has thus resulted in a better rate performance. Further density functional theory simulations have revealed that the origin of such kinetic enhancement was from the distortion of molecular configurations of the LiPSs anchored on p-C3N4. Therefore, this proof-of-concept study opens up a promising avenue to improve the performance of Li-S batteries by accelerating their fundamental electrochemical redox processes, which also has the potential to be applied in other electrochemical energy storage/conversion systems.

  2. Effects of carbon-to-sulfur (C/S) ratio and nitrate (N) dosage on Denitrifying Sulfur cycle-associated Enhanced Biological Phosphorus Removal (DS-EBPR)

    Science.gov (United States)

    Yu, Mei; Lu, Hui; Wu, Di; Zhao, Qing; Meng, Fangang; Wang, Yudan; Hao, Xiaodi; Chen, Guang-Hao

    2016-03-01

    In this study, the Denitrifying Sulfur cycle-associated Enhanced Biological Phosphorous Removal (DS-EBPR) with 20 mg P/L/d of the volumetric P removal rate was successfully achieved in a Sequencing Batch Reactor (SBR). The effects of carbon-to-sulfur (C/S) mass ratio and nitrate (N) dosage were investigated through two batch tests to reveal the role of wastewater compositions in DS-EBPR performance. The optimal specific P release and uptake rates (0.4 and 2.4 mg P/g VSS/h, respectively) were achieved at C/S/P/N mass ratio of 150/200/20/20, and poly-S is supplied as a potential electron and energy storage. The nitrate dosage in a range of 10-50 mg N/L had no significant influence on P uptake rates (2.1 ~ 2.4 mg P/g VSS/h), but significantly affected the storage of inclusion poly-S, the poly-S oxidation rate was increased about 16% while dosing nitrate from 20 to 30 mg N/L. It implies that nitrate is denitrified in the P uptake phase, and excess nitrate is further consumed by poly-S. Moreover, the microbial analysis showed that the functional bacteria should mostly belong to denitrifying bacteria or Unclassified genera.

  3. Development of large scale internal reforming molten carbonate fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, A.; Shinoki, T.; Matsumura, M. [Mitsubishi Electric Corp., Hyogo (Japan)

    1996-12-31

    Internal Reforming (IR) is a prominent scheme for Molten Carbonate Fuel Cell (MCFC) power generating systems in order to get high efficiency i.e. 55-60% as based on the Higher Heating Value (HHV) and compact configuration. The Advanced Internal Reforming (AIR) technology has been developed based on two types of the IR-MCFC technology i.e. Direct Internal Reforming (DIR) and Indirect Internal Reforming (DIR).

  4. A one-step moderate-explosion assisted carbonization strategy to sulfur and nitrogen dual-doped porous carbon nanosheets derived from camellia petals for energy storage

    Science.gov (United States)

    Wei, Tongye; Wei, Xiaolin; Yang, Liwen; Xiao, Huaping; Gao, Yong; Li, Huaming

    2016-11-01

    A one-step moderate-explosion assisted carbonization strategy is demonstrated for the synthesis of sulfur and nitrogen dual-doped porous carbon nanosheets (CNSs) using the mixture of camellia petals and ammonium persulfate. The ammonium persulfate acts as both explosive and dopant precursor. The prepared porous carbon nanosheets have high BET surface than 1122 m2 g-1 with sulfur and nitrogen contents of 1.34% and 4.89%, respectively, which benefit the improvement of conductivity, wettability and active sites for electrochemical reaction. The electrochemical tests as electrodes materials for supercapacitor, lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) indicate that the prepared sulfur and nitrogen dual-doped porous carbon nanosheets possess superior energy-storage performance. The specific capacitances of the CNS-800 symmetric two-electrode supercapacitors using 6 M KOH liquid and KOH/PVA solid-state electrolytes for high current density of 20 A g-1 are up to 176.2 F g-1 and 136.0 F g-1, respectively. The CNS-800 anodes exhibit high capacities as well as good cycle performance with capacitance of 310 mA h g-1 and 129 mA h g-1 after 1000 cycles at 0.2 A g-1 for LIBs and SIBs, respectively. The results provide a novel route for low-cost and large-scale production of CNSs electrode materials for high-performance electrochemical energy storage devices.

  5. Spectroscopic characteristics of carbon dots (C-dots) derived from carbon fibers and conversion to sulfur-bridged C-dots nanosheets.

    Science.gov (United States)

    Vinci, John C; Ferrer, Ivonne M; Guterry, Nathan W; Colón, Verónica M; Destino, Joel F; Bright, Frank V; Colón, Luis A

    2015-09-01

    We synthesized sub-10 nm carbon nanoparticles (CNPs) consistent with photoluminescent carbon dots (C-dots) from carbon fiber starting material. The production of different C-dots fractions was monitored over seven days. During the course of the reaction, one fraction of C-dots species with relatively high photoluminescence was short-lived, emerging during the first hour of reaction but disappearing after one day of reaction. Isolation of this species during the first hour of the reaction was crucial to obtaining higher-luminescent C-dots species. When the reaction proceeded for one week, the appearance of larger nanostructures was observed over time, with lateral dimensions approaching 200 nm. The experimental evidence suggests that these larger species are formed from small C-dot nanoparticles bridged together by sulfur-based moieties between the C-dot edge groups, as if the C-dots polymerized by cross-linking the edge groups through sulfur bridges. Their size can be tailored by controlling the reaction time. Our results highlight the variety of CNP products, from sub-10 nm C-dots to ~200 nm sulfur-containing carbon nanostructures, that can be produced over time during the oxidation reaction of the graphenic starting material. Our work provides a clear understanding of when to stop the oxidation reaction during the top-down production of C-dots to obtain highly photoluminescent species or a target average particle size.

  6. Sulfur metabolism in phototrophic sulfur bacteria

    DEFF Research Database (Denmark)

    Frigaard, Niels-Ulrik; Dahl, Christiane

    2008-01-01

    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...

  7. Sulfur-doped nanoporous carbon spheres with ultrahigh specific surface area and high electrochemical activity for supercapacitor

    Science.gov (United States)

    Liu, Simin; Cai, Yijin; Zhao, Xiao; Liang, Yeru; Zheng, Mingtao; Hu, Hang; Dong, Hanwu; Jiang, Sanping; Liu, Yingliang; Xiao, Yong

    2017-08-01

    Development of facile and scalable synthesis process for the fabrication of nanoporous carbon materials with large specific surface areas, well-defined nanostructure, and high electrochemical activity is critical for the high performance energy storage applications. The key issue is the dedicated balance between the ultrahigh surface area and highly porous but interconnected nanostructure. Here, we demonstrate the fabrication of new sulfur doped nanoporous carbon sphere (S-NCS) with the ultrahigh surface area up to 3357 m2 g-1 via a high-temperature hydrothermal carbonization and subsequent KOH activation process. The as-prepared S-NCS which integrates the advantages of ultrahigh porous structure, well-defined nanospherical and modification of heteroatom displays excellent electrochemical performance. The best performance is obtained on S-NCS prepared by the hydrothermal carbonization of sublimed sulfur and glucose, S-NCS-4, reaching a high specific capacitance (405 F g-1 at a current density of 0.5 A g-1) and outstanding cycle stability. Moreover, the symmetric supercapacitor is assembled by S-NCS-4 displays a superior energy density of 53.5 Wh kg-1 at the power density of 74.2 W kg-1 in 1.0 M LiPF6 EC/DEC. The synthesis method is simple and scalable, providing a new route to prepare highly porous and heteroatom-doped nanoporous carbon spheres for high performance energy storage applications.

  8. Nanocasting hierarchical carbide-derived carbons in nanostructured opal assemblies for high-performance cathodes in lithium-sulfur batteries.

    Science.gov (United States)

    Hoffmann, Claudia; Thieme, Sören; Brückner, Jan; Oschatz, Martin; Biemelt, Tim; Mondin, Giovanni; Althues, Holger; Kaskel, Stefan

    2014-12-23

    Silica nanospheres are used as templates for the generation of carbide-derived carbons with monodisperse spherical mesopores (d=20-40 nm) and microporous walls. The nanocasting approach with a polycarbosilane precursor and subsequent pyrolysis, followed by silica template removal and chlorine treatment, results in carbide-derived carbons DUT-86 (DUT=Dresden University of Technology) with remarkable textural characteristics, monodisperse, spherical mesopores tunable in diameter, and very high pore volumes up to 5.0 cm3 g(-1). Morphology replication allows these nanopores to be arranged in a nanostructured inverse opal-like structure. Specific surface areas are very high (2450 m2 g(-1)) due to the simultaneous presence of micropores. Testing DUT-86 samples as cathode materials in Li-S batteries reveals excellent performance, and tailoring of the pore size allows optimization of cell performance, especially the active center accessibility and sulfur utilization. The outstanding pore volumes allow sulfur loadings of 80 wt %, a value seldom achieved in composite cathodes, and initial capacities of 1165 mAh gsulfur(-1) are reached. After 100 cycle capacities of 860 mAh gsulfur(-1) are retained, rendering DUT-86 a high-performance sulfur host material.

  9. Cu-based metal-organic framework/activated carbon composites for sulfur compounds removal

    Science.gov (United States)

    Shi, Rui-Hua; Zhang, Zhen-Rong; Fan, Hui-Ling; Zhen, Tian; Shangguan, Ju; Mi, Jie

    2017-02-01

    MOF-199 was modified by incorporating activated carbon (AC) during its synthesis under hydrothermal conditions to improve its performance in the removal of hydrogen sulfide (H2S) and dimethyl sulfide (CH3SCH3). A variety of different characterization techniques including X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, nitrogen adsorption/desorption isotherms, scanning electron microscopy (SEM), pyridine adsorption infrared spectroscopy (Py-IR), thermogravimetric- mass spectroscopy (TG-MS) and X-ray photoelectron spectroscopy (XPS) were used to analyze the fresh and exhausted composites. It was found that the composites, which have an amount of AC of less than 2%, had the same morphology as those of pristine MOF-199, but exhibited a more ordered crystallinity structure as well as higher surface area. The composite with 2% AC incorporation showed highest sulfur capacity of 8.46 and 8.53% for H2S and CH3SCH3, respectively, which increased by 51 and 41% compared to that of MOF-199. This improvement was attributed to the formation of more micropores and especially the increased number of unsaturated copper metal sites, as revealed by Py-IR. It is suggested the chemical reaction was apparent during adsorption of H2S, which resulted in the formation of CuS and the collapse of the MOF structure. Whereas reversible chemisorption was found for CH3SCH3 adsorption, as testified by TG-MS and fixed-bed regeneration. Exhausted MAC-2 can be almost totally regenerated by high temperature 180 °C nitrogen purge, indicating a promising adsorbent for CH3SCH3 removal.

  10. Self-assembly of biomorphic carbon/sulfur microstructures in sulfidic environments

    OpenAIRE

    Cosmidis, Julie; Templeton, Alexis S.

    2016-01-01

    In natural and laboratory-based environments experiencing sustained counter fluxes of sulfide and oxidants, elemental sulfur (S0)—a key intermediate in the sulfur cycle—can commonly accumulate. S0 is frequently invoked as a biomineralization product generated by enzymatic oxidation of hydrogen sulfide and polysulfides. Here we show the formation of S0 encapsulated in nanometre to micrometre-scale tubular and spherical organic structures that self-assemble in sulfide gradient environments in t...

  11. Supercapacitance of nitrogen-sulfur-oxygen co-doped 3D hierarchical porous carbon in aqueous and organic electrolyte

    Science.gov (United States)

    Yang, Wang; Yang, Wu; Song, Ailing; Gao, Lijun; Su, Li; Shao, Guangjie

    2017-08-01

    This work report the synthesis of porous carbon with hierarchical pore structure and uniform nitrogen-sulfur-oxygen doping. The favorable pore structure (micro-, meso-, and macro-pores) is beneficial to ion adsorption and transportation, and the doping heteroatoms can introduce electrochemical active sites which contribute to additional pseudocapacitance. Therefore, the carbon material shows good electrochemical performance when employed as supercapacitor electrode. High specific capacitance (367 F g-1 at 0.3 A g-1), good rate performance and stable cycling characteristics are obtained in 6 M KOH. In addition, when tested in 1 M H2SO4, a higher specific capacitance (382 F g-1 at 0.3 A g-1) is delivered. Furthermore, the assembled symmetric cell yields a maximum specific energy of 35.3 W h kg-1 in 1 M TEABF4/AN, significantly improving the specific energy of carbon-based supercapacitors.

  12. Carbon dioxide emissions from international air freight

    Science.gov (United States)

    Howitt, Oliver J. A.; Carruthers, Michael A.; Smith, Inga J.; Rodger, Craig J.

    2011-12-01

    Greenhouse gas emissions from international air transport were excluded from reduction targets under the Kyoto Protocol, partly because of difficulties with quantifying and apportioning such emissions. Although there has been a great deal of recent research into calculating emissions from aeroplane operations globally, publicly available emissions factors for air freight emissions are scarce. This paper presents a methodology to calculate the amount of fuel burnt and the resulting CO 2 emissions from New Zealand's internationally air freighted imports and exports in 2007. This methodology could be applied to other nations and/or regions. Using data on fuel uplift, air freight and air craft movements, and assumptions on mean passenger loadings and the mass of passengers and air freight, CO 2 emissions factors of 0.82 kg CO 2 per t-km and 0.69 kg CO 2 per t-km for short-haul and long-haul journeys, respectively, were calculated. The total amount of fuel consumed for the international air transport of New Zealand's imports and exports was calculated to be 0.21 Mt and 0.17 Mt respectively, with corresponding CO 2 emissions of 0.67 Mt and 0.53 Mt.

  13. The Effect of Oxidation on the Surface Chemistry of Sulfur-Containing Carbons and their Arsine Adsorption Capacity

    Science.gov (United States)

    2010-01-01

    hydrogen sulfide . Carbon 2004;42(3):469–76. Fig. 6 – Water adsorption isotherms of the samples studied. 1786 C A R B O N 4 8 ( 2 0 1 0 ) 1 7 7 9 –1 7 8...that oxygen- and sulfur-containing groups participate in arsine oxida- tion to arsenic tri- and pentoxide and/or in the formation of arsenic sulfides ...technological difficulties, arsine is also a powerful toxin susceptible to oxidation with a strong exothermic effect. Of all the methods to separate

  14. Determination of chlorine, sulfur and carbon in reinforced concrete structures by double-pulse laser-induced breakdown spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Labutin, Timur A., E-mail: timurla@laser.chem.msu.ru [Lomonosov Moscow State University, Department of Chemistry, Leninskie Gory 1-3, Moscow 119991 (Russian Federation); Popov, Andrey M.; Zaytsev, Sergey M.; Zorov, Nikita B. [Lomonosov Moscow State University, Department of Chemistry, Leninskie Gory 1-3, Moscow 119991 (Russian Federation); Belkov, Mikhail V.; Kiris, Vasilii V.; Raikov, Sergey N. [B.I. Stepanov Institute of Physics, Nezavisimosti Ave. 68, Minsk 220072 (Belarus)

    2014-09-01

    Accurate and reliable quantitative determination of non-metal corrosion agents in concrete is still an actual task of analytical use of LIBS. Two double-pulse LIBS systems were tested as a tool for the determination of chlorine, sulfur and carbon in concretes. Both systems had collinear configuration; a laboratory setup was equipped with an ICCD and two lasers (355/532 nm + 540 nm), but a CCD was a detector for a mobile system with one laser (1064 nm). Analytical lines of Cl I at 837.59 nm, S I at 921 nm and C I at 247.86 nm were used to plot calibration curves. Optimal interpulse delays for the laboratory setup were 4 μs for chlorine and 2.8 μs for carbon, while an interpulse delay of 2 μs was optimal for chlorine and sulfur determination with the mobile system. We suggested the normalization of the Cl I line at 837.59 nm to the Mg II line at 279.08 nm (visible at 837.23 nm in the third order) to compensate for pulse-to-pulse fluctuations of chlorine lines. It provided the decrease of the detection limit of chlorine from 400 ppm to 50 ppm. Therefore, we reported that LIBS can be used to determine main corrosive active substances under ambient conditions in concrete below critical threshold values. Moreover, the application of the mobile system for in-situ qualitative assessment of corrosion way of a steel cage of a swimming pool dome was also demonstrated. It was found that chloride corrosion due to the disinfection of water was the main way for corrosion of the open part steel and the steel rebar inside the concrete. - Highlights: • Determination of chlorine, sulfur and carbon in concrete in the air. • Comparison of mobile and laboratory LIBS systems. • LOD by double-pulse LIBS under ambient conditions: for sulfur 1500 ppm, for chlorine — 50 ppm. • Background level of carbon content in concrete is about 0.27% wt.

  15. Uniform Li2S precipitation on N,O-codoped porous hollow carbon fibers for high-energy-density lithium-sulfur batteries with superior stability.

    Science.gov (United States)

    Qie, Long; Manthiram, Arumugam

    2016-09-21

    A lithium-polysulfide cell with superior stability is reported with N,O-codoped carbon hollow fiber (NCHF) sheets as a current collector. Due to the highly effective chemisorption and physical adsorption of lithium polysulfides on doped NCHF and a uniform Li2S precipitation during cycling, the Li2S6-impregnated NCHF electrodes exhibit high sulfur utilization and superior cycling stability even with a high areal sulfur loading of 6.2 mg cm(-2).

  16. Simultaneous Analysis of Nitrogen, Carbon and Sulfur Stable Isotopes and Concentrations in Organics and Soils

    Science.gov (United States)

    Mambelli, S.; Brooks, P. D.; Sutka, R.; Hughes, S.; Finstad, K. M.; Pakes, M. J.; Dawson, T. E.

    2014-12-01

    To date, analysis of diet, food web complexities, biogeochemical cycles, and ecosystem functioning have largely focused on using variation in carbon (C) and nitrogen (N) stable isotope ratios. This is because a great deal is understood about what leads to this variation and because the dual stable isotope analysis of these two elements using continuous flow isotope ratio mass spectrometry (IRMS) is now commonplace. However, the aforementioned studies may all greatly benefit from the additional information one can get from also having sulfur (S) stable isotopes ratio data. Until very recently the analysis of δ34S has traditionally required an additional and often more difficult analytical procedure. Here, we report on the development of a new method that simultaneously analyzes the elemental and isotopic composition of N, C and S in a single sample. The new commercially available instrument includes a modified NCS elemental analyzer in line with an IRMS outfitted with 100 volt AD converters for wide dynamic range. We tested, and modified, this instrument to achieve maximum accuracy and precision for the isotopic measurements of all three elements. We found that the original design needed improvements to achieve our goals by: a) including a component (originally designed for trapping water) as buffer to reduce S memory and obtain reliable δ34S analysis; b) adding an external furnace for complete reduction of nitrogen oxides to N2 gas for accurate δ15N; c) adding a magnesium perchlorate water trap immediately after the reduction tube to minimize any water condensation that could also influence S memory. We analyzed a selection of organic materials and soils with approximately a 1:2 standards versus unknowns ratio per run. Using this NCS set-up, the precision of the N and C isotopic measurements was comparable to the one usually attained in NC mode alone (standard deviation of ± 0.13 δ15N in the range 30 to 400 µg N, and of ± 0.12 δ13C in the range 0.20 to 4 mg

  17. A simple fabrication for sulfur doped graphitic carbon nitride porous rods with excellent photocatalytic activity degrading RhB dye

    Science.gov (United States)

    Fan, Qianjing; Liu, Jianjun; Yu, Yingchun; Zuo, Shengli; Li, Baoshan

    2017-01-01

    Constructing special nanostructures with large surface areas and tuning the band gap by element doping are efficient strategies to enhance the photocatalytic activity of semiconductor materials. Here we combined both strategies in one material to form sulfur-doped graphitic carbon nitride porous rods (S-pg-C3N4) in one pot by simply pyrolysis of the melamine-trithiocyanuric acid complex with different temperatures. The samples were characterized by XRD, FT-IR, and elemental analysis; nitrogen adsorption isotherms, SEM and TEM images; and UV-vis DRS and photoluminescence spectra. Characterizations showed that S-pg-C3N4 possessed porous rod structure with a larger surface area (20-52 m2/g) than that of bulk g-C3N4, and the surface area of the S-pg-C3N4 samples increased with the increase of heating temperature. Meanwhile, the trace sulfur remained in the framework of g-C3N4 formed sulfur doped g-C3N4, and the visible light absorption edge of the S-pg-C3N4 was extended, corresponding to a narrowed band gap. As a result, the S-pg-C3N4 samples exhibited an enhanced physical adsorption and photocatalytic activity in the degradation of Rhodamine B dye under visible light.

  18. Microporous activated carbons prepared from palm shell by thermal activation and their application to sulfur dioxide adsorption.

    Science.gov (United States)

    Guo, Jia; Lua, Aik Chong

    2002-07-15

    Textural characterization of activated carbons prepared from palm shell by thermal activation with carbon dioxide (CO(2)) gas is reported in this paper. Palm shell (endocarp) is an abundant agricultural solid waste from palm-oil processing mills in many tropical countries such as Malaysia, Indonesia, and Thailand. The effects of activation temperature on the textural properties of the palm-shell activated carbons, namely specific surface area (BET method), porosity, and microporosity, were investigated. The activated carbons prepared from palm shell possessed well-developed porosity, predominantly microporosity, leading to potential applications in gas-phase adsorption for air pollution control. Static and dynamic adsorption tests for sulfur dioxide (SO(2)), a common gaseous pollutant, were carried out in a thermogravimetric analyzer and a packed column configuration respectively. The effects of adsorption temperature, adsorbate inlet concentration, and adsorbate superficial velocity on the adsorptive performance of the prepared activated carbons were studied. The palm-shell activated carbon was found to have substantial capability for the adsorption of SO(2), comparable to those of some commercial products and an adsorbent derived from another biomass.

  19. Activated Carbon Catalysts for the Production of Hydrogen for the Sulfur-Iodine Thermochemical Water Splitting Cycle

    Energy Technology Data Exchange (ETDEWEB)

    Lucia M. Petkovic; Daniel M. Ginosar; Harry W. Rollins; Kyle C Burch; Cristina Deiana; Hugo S. Silva; Maria F. Sardella; Dolly Granados

    2009-05-01

    Seven activated carbon catalysts obtained from a variety of raw material sources and preparation methods were examined for their catalytic activity to decompose hydroiodic acid (HI) to produce hydrogen; a key reaction in the sulfur-iodine (S-I) thermochemical water splitting cycle. Activity was examined under a temperature ramp from 473 to 773 K. Within the group of ligno-cellulosic steam-activated carbon catalysts, activity increased with surface area. However, both a mineral-based steam-activated carbon and a ligno-cellulosic chemically-activated carbon displayed activities lower than expected based on their higher surface areas. In general, ash content was detrimental to catalytic activity while total acid sites, as determined by Bohem’s titrations, seemed to favor higher catalytic activity within the group of steam-activated carbons. These results suggest, one more time, that activated carbon raw materials and preparation methods may have played a significant role in the development of surface characteristics that eventually dictated catalyst activity and stability as well.

  20. Activated carbon catalysts for the production of hydrogen via the sulfur-iodine thermochemical water splitting cycle

    Energy Technology Data Exchange (ETDEWEB)

    Petkovic, Lucia M.; Ginosar, Daniel M.; Rollins, Harry W.; Burch, Kyle C. [Idaho National Laboratory, Interfacial Chemistry, P.O. Box 1625, Idaho Falls, ID 83415-2208 (United States); Deiana, Cristina; Silva, Hugo S.; Sardella, Maria F.; Granados, Dolly [Instituto de Ingenieria Quimica, Facultad de Ingenieria, Universidad Nacional de San Juan, Libertador 1109 (oeste) 5400 San Juan (Argentina)

    2009-05-15

    Seven activated carbon catalysts obtained from a variety of raw material sources and preparation methods were examined for their catalytic activity to decompose hydrogen iodide (HI) to produce hydrogen, a key reaction in the sulfur-iodine (S-I) thermochemical water splitting cycle. Activity was examined under a temperature ramp from 473 to 773 K. Within the group of lignocellulosic steam-activated carbon catalysts, activity increased with surface area. However, both a mineral-based steam-activated carbon and a lignocellulosic chemically activated carbon displayed activities lower than expected based on their higher surface areas. In general, ash content was detrimental to catalytic activity while total acid sites, as determined by Boehm's titrations, seemed to favor higher catalytic activity within the group of steam-activated carbons. These results suggest that activated carbon raw materials and preparation methods may have played a significant role in the development of surface characteristics that eventually dictated catalyst activity and stability as well. (author)

  1. Effects of tempering on internal friction of carbon steels

    Energy Technology Data Exchange (ETDEWEB)

    Hoyos, J.J., E-mail: jjhoyos@unal.edu.co [Grupo de Ciencia y Tecnologia de los Materiales, Universidad Nacional de Colombia, Sede Medellin, Carrera 80 Numero 65-223, Medellin (Colombia); Ghilarducci, A.A., E-mail: friccion@cab.cnea.gov.ar [Centro Atomico Bariloche, Comision Nacional de Energia Atomica, Instituto Balseiro-Universidad Nacional de Cuyo, Consejo Nacional de Investigaciones Cientificas y Tecnologicas, Av. Bustillo 9500, 8400 Bariloche RN (Argentina); Salva, H.R., E-mail: salva@cab.cnea.gov.ar [Centro Atomico Bariloche, Comision Nacional de Energia Atomica, Instituto Balseiro-Universidad Nacional de Cuyo, Consejo Nacional de Investigaciones Cientificas y Tecnologicas, Av. Bustillo 9500, 8400 Bariloche RN (Argentina); Chaves, C.A., E-mail: cachaves@unal.edu.co [Grupo de Ciencia y Tecnologia de los Materiales, Universidad Nacional de Colombia, Sede Medellin, Carrera 80 Numero 65-223, Medellin (Colombia); Velez, J.M., E-mail: jmvelez@unal.edu.co [Grupo de Ciencia y Tecnologia de los Materiales, Universidad Nacional de Colombia, Sede Medellin, Carrera 80 Numero 65-223, Medellin (Colombia)

    2011-04-15

    Research highlights: {yields} Time tempering dependent microstructure of two steels is studied by internal friction. {yields} Internal friction indicates the interactions of dislocations with carbon and carbides. {yields} Internal friction detects the first stage of tempering. {yields} Precipitation hardening is detected by the decrease in the background. - Abstract: Two steels containing 0.626 and 0.71 wt.% carbon have been studied to determine the effects of tempering on the microstructure and the internal friction. The steels were annealed at 1093 K, quenched into water and tempered for 60 min at 423 K, 573 K and 723 K. The increase of the tempering time diminishes the martensite tetragonality due to the redistribution of carbon atoms from octahedrical interstitial sites to dislocations. Internal friction spectrum is decomposed into five peaks and an exponential background, which are attributed to the carbide precipitation and the dislocation relaxation process. Simultaneous presence of peaks P1 and P2 indicates the interaction of dislocations with the segregated carbon and carbide precipitate.

  2. An efficient hydrogenation catalyst in sulfuric acid for the conversion of nitrobenzene to p-aminophenol: N-doped carbon with encapsulated molybdenum carbide.

    Science.gov (United States)

    Wang, Tao; Dong, Zhen; Cai, Weimeng; Wang, Yongzheng; Fu, Teng; Zhao, Bin; Peng, Luming; Ding, Weiping; Chen, Yi

    2016-08-23

    The transfer of catalytic function from molybdenum carbide to N-doped carbon has been tested by encapsulating molybdenum carbide with N-doped carbon using a one-pot preparation process. The outer layer of N-doped carbon, inert itself, exhibits high activity and excellent selectivity with molybdenum carbide as the catalyst for the hydrogenation of nitrobenzene to p-aminophenol in sulfuric acid.

  3. Soft cutting of single-wall carbon nanotubes by low temperature ultrasonication in a mixture of sulfuric and nitric acids

    Science.gov (United States)

    Shuba, M. V.; Paddubskaya, A. G.; Kuzhir, P. P.; Maksimenko, S. A.; Ksenevich, V. K.; Niaura, G.; Seliuta, D.; Kasalynas, I.; Valusis, G.

    2012-12-01

    To decrease single-wall carbon nanotube (SWCNT) lengths to a value of 100-200 nm, aggressive cutting methods, accompanied by a high loss of starting material, are frequently used. We propose a cutting approach based on low temperature intensive ultrasonication in a mixture of sulfuric and nitric acids. The method is nondestructive with a yield close to 100%. It was applied to cut nanotubes produced in three different ways: gas-phase catalysis, chemical vapor deposition, and electric-arc-discharge methods. Raman and Fourier transform infrared spectroscopy were used to demonstrate that the cut carbon nanotubes have a low extent of sidewall degradation and their electronic properties are close to those of the untreated tubes. It was proposed to use the spectral position of the far-infrared absorption peak as a simple criterion for the estimation of SWCNT length distribution in the samples.

  4. Nickel catalysts for internal reforming in molten carbonate fuel cells

    NARCIS (Netherlands)

    Berger, R.J.; Doesburg, E.B.M.; Ommen, van J.G.; Ross, J.R.H.

    1996-01-01

    Natural gas may be used instead of hydrogen as fuel for the molten carbonate fuel cell (MCFC) by steam reforming the natural gas inside the MCFC, using a nickel catalyst (internal reforming). The severe conditions inside the MCFC, however, require that the catalyst has a very high stability. In orde

  5. Optimization of Pore Structure of Cathodic Carbon Supports for Solvate Ionic Liquid Electrolytes Based Lithium-Sulfur Batteries.

    Science.gov (United States)

    Zhang, Shiguo; Ikoma, Ai; Li, Zhe; Ueno, Kazuhide; Ma, Xiaofeng; Dokko, Kaoru; Watanabe, Masayoshi

    2016-10-04

    Lithium-sulfur (Li-S) batteries are a promising energy-storage technology owing to their high theoretical capacity and energy density. However, their practical application remains a challenge because of the serve shuttle effect caused by the dissolution of polysulfides in common organic electrolytes. Polysulfide-insoluble electrolytes, such as solvate ionic liquids (ILs), have recently emerged as alternative candidates and shown great potential in suppressing the shuttle effect and improving the cycle stability of Li-S batteries. Redox electrochemical reactions in polysulfide-insoluble electrolytes occur via a solid-state process at the interphase between the electrolyte and the composite cathode; therefore, creating an appropriate interface between sulfur and a carbon support is of great importance. Nevertheless, the porous carbon supports established for conventional organic electrolytes may not be suitable for polysulfide-insoluble electrolytes. In this work, we investigated the effect of the porous structure of carbon materials on the Li-S battery performance in polysulfide-insoluble electrolytes using solvate ILs as a model electrolyte. We determined that the pore volume (rather than the surface area) exerts a major influence on the discharge capacity of S composite cathodes. In particular, inverse opal carbons with three-dimensionally ordered interconnected macropores and a large pore volume deliver the highest discharge capacity. The battery performance in both polysulfide-soluble electrolytes and solvate ILs was used to study the effect of electrolytes. We propose a plausible mechanism to explain the different porous structure requirements in polysulfide-soluble and polysulfide-insoluble electrolytes.

  6. Sulfide-oxidizing bacteria establishment in an innovative microaerobic reactor with an internal silicone membrane for sulfur recovery from wastewater.

    Science.gov (United States)

    Valdés, F; Camiloti, P R; Rodriguez, R P; Delforno, T P; Carrillo-Reyes, J; Zaiat, M; Jeison, D

    2016-06-01

    A novel bioreactor, employing a silicone membrane for microaeration, was studied for partial sulfide oxidation to elemental sulfur. The objective of this study was to assess the feasibility of using an internal silicone membrane reactor (ISMR) to treat dissolved sulfide and to characterize its microbial community. The ISMR is an effective system to eliminate sulfide produced in anaerobic reactors. Sulfide removal efficiencies reached 96 % in a combined anaerobic/microaerobic reactor and significant sulfate production did not occur. The oxygen transfer was strongly influenced by air pressure and flow. Pyrosequencing analysis indicated various sulfide-oxidizing bacteria (SOB) affiliated to the species Acidithiobacillus thiooxidans, Sulfuricurvum kujiense and Pseudomonas stutzeri attached to the membrane and also indicated similarity between the biomass deposited on the membrane wall and the biomass drawn from the material support, supported the establishment of SOB in an anaerobic sludge under microaerobic conditions. Furthermore, these results showed that the reactor configuration can develop SOB under microaerobic conditions and can improve and reestablish the sulfide conversion to elemental sulfur.

  7. Interfacial Reaction Dependent Performance of Hollow Carbon NanoSphere – Sulfur composite as a cathode for Li-S battery

    Directory of Open Access Journals (Sweden)

    Jianming eZheng

    2015-05-01

    Full Text Available Lithium-sulfur (Li-S battery is a promising energy storage system due to its high energy density, cost effectiveness and environmental friendliness of sulfur. However, there are still a number of technical challenges, such as low Coulombic efficiency and poor long-term cycle life, impeding the commercialization of Li-S battery. The electrochemical performance of Li-S battery is closely related with the interfacial reactions occurring between hosting substrate and active sulfur species which are poorly conducting at fully oxidized and reduced states. Here, we correlate the relationship between the performance and interfacial reactions in the Li-S battery system, using a hollow carbon nanosphere (HCNS with highly graphitic character as hosting substrate for sulfur. With an appropriate amount of sulfur loading, HCNS/S composite exhibits excellent electrochemical performance because of the fast interfacial reactions between HCNS and the polysulfides. However, further increase of sulfur loading leads to increased formation of highly resistive insoluble reaction products (Li2S2/Li2S which limits the reversibility of the interfacial reactions and results in poor electrochemical performances. These findings demonstrate the importance of the interfacial reaction reversibility in the whole electrode system on achieving high capacity and long cycle life of sulfur cathode for Li-S batteries.

  8. Sulfur enriched carbon nanotubols with a Poly(3,4-ethylenedioxypyrrole) coating as cathodes for long-lasting Li-S batteries

    Science.gov (United States)

    Mukkabla, Radha; Meduri, Praveen; Deepa, Melepurath; Shivaprasad, S. M.; Ghosal, Partha

    2017-02-01

    Lithium-sulfur (Li-S) batteries are technologically significant for sulfur is cheap, and offers high gravimetric capacity and a large energy density. But achieving long term cyclability with moderate capacity loss, and scalability pose formidable challenges. A solution phase approach for the preparation of a composite of sulfur with hydroxyl groups functionalized multiwalled carbon nanotubes (MWCNTols) and coated with poly(3,4-ethylenedioxypyrrole) (PEDOP) is presented for the first time. Comparison of the Li-S performances at 0.1 C current-rate show that the S based cell with a S-loading of 80% retains a low capacity of 122 mAh gsulfur-1 after 100 cycles, whereas cells with S/MWCNTols and S/MWCNTols/PEDOP composites with sulfur loadings of 73 and 70% respectively, retain capacities of 384 and 624 mAh gsulfur-1 after 200 charge-discharge cycles, with Coulombic efficiencies of 96 and 98.7% respectively. This performance differential illustrates the role of PEDOP in inhibiting sulfur loss and in maximizing cell response. The polymer provides electrical interconnects between the insulating sulfur clusters and facilitates Li+ transfer at the interface. The ease of the synthesis, coupled with the remarkable cycling performance delivered by this composite at a high sulfur-loading, demonstrate the promise that this S/CNT/conducting polymer composite has for practical Li-S batteries.

  9. Sulfate reduction in sulfuric material after re-flooding: Effectiveness of organic carbon addition and pH increase depends on soil properties.

    Science.gov (United States)

    Yuan, Chaolei; Fitzpatrick, Rob; Mosley, Luke M; Marschner, Petra

    2015-11-15

    Sulfuric material is formed upon oxidation of sulfidic material; it is extremely acidic, and therefore, an environmental hazard. One option for increasing pH of sulfuric material may be stimulation of bacterial sulfate reduction. We investigated the effects of organic carbon addition and pH increase on sulfate reduction after re-flooding in ten sulfuric materials with four treatments: control, pH increase to 5.5 (+pH), organic carbon addition with 2% w/w finely ground wheat straw (+C), and organic carbon addition and pH increase (+C+pH). After 36 weeks, in five of the ten soils, only treatment +C+pH significantly increased the concentration of reduced inorganic sulfur (RIS) compared to the control and increased the soil pore water pH compared to treatment+pH. In four other soils, pH increase or/and organic carbon addition had no significant effect on RIS concentration compared to the control. The RIS concentration in treatment +C+pH as percentage of the control was negatively correlated with soil clay content and initial nitrate concentration. The results suggest that organic carbon addition and pH increase can stimulate sulfate reduction after re-flooding, but the effectiveness of this treatment depends on soil properties.

  10. Honeysuckle-derived hierarchical porous nitrogen, sulfur, dual-doped carbon for ultra-high rate lithium ion battery anodes

    Science.gov (United States)

    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.

  11. Carbon and sulfur isotopic compositions of basal Datangpo Formation, northeastern Guizhou, South China: Implications for depositional environment

    Institute of Scientific and Technical Information of China (English)

    Xi Chen; Da Li; Hong-Fei Ling; Shao-Yong Jiang

    2008-01-01

    Isotopic compositions of Mn-carbonate and organic carbon from the same individual samples and sulfur isotopic compositions of pyrites in the basal Datangpo Formation were analyzed. Highly 34S-enriched pyrites (δ34Spyrite = 31.7-59.4‰) were precipitated in relatively occlusive pore water under anoxic condition in sediments, which is consistent with the observation of large and scattered pyrite framboids. The sulfidic deep ocean was not "oxidized" in the early Datangpo interglacial interval, thus the level of seawater sulfate remained low and marine δ3.4Ssuiphate remained high. Low δ13Ccar (average - 7.4‰) and abnormal relationship between δ13Ccar and frac-tionation (Δcar-org) imply that the negative δ13Ccar excursion may have resulted from oxidation of part of a large organic carbon reservoir. High Δcar-org (average 25A‰) implicates high CO2 level in the atmosphere. Small standard deviation (1.0‰) of δ13Ccar values indicates the Mn-carbonate was precipitated near the water-sediment interface under dysoxic conditions rather than in occlusive pore water in sediments.

  12. The internal consistency of the North Sea carbonate system

    Science.gov (United States)

    Salt, Lesley A.; Thomas, Helmuth; Bozec, Yann; Borges, Alberto V.; de Baar, Hein J. W.

    2016-05-01

    In 2002 (February) and 2005 (August), the full suite of carbonate system parameters (total alkalinity (AT), dissolved inorganic carbon (DIC), pH, and partial pressure of CO2 (pCO2) were measured on two re-occupations of the entire North Sea basin, with three parameters (AT, DIC, pCO2) measured on four additional re-occupations, covering all four seasons, allowing an assessment of the internal consistency of the carbonate system. For most of the year, there is a similar level of internal consistency, with AT being calculated to within ± 6 μmol kg- 1 using DIC and pH, DIC to ± 6 μmol kg- 1 using AT and pH, pH to ± 0.008 using AT and pCO2, and pCO2 to ± 8 μatm using DIC and pH, with the dissociation constants of Millero et al. (2006). In spring, however, we observe a significant decline in the ability to accurately calculate the carbonate system. Lower consistency is observed with an increasing fraction of Baltic Sea water, caused by the high contribution of organic alkalinity in this water mass, not accounted for in the carbonate system calculations. Attempts to improve the internal consistency by accounting for the unconventional salinity-borate relationships in freshwater and the Baltic Sea, and through application of the new North Atlantic salinity-boron relationship (Lee et al., 2010), resulted in no significant difference in the internal consistency.

  13. Processes for preparing carbon fibers using sulfur trioxide in a halogenated solvent

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Institute of Scientific and Technical Information of China (English)

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

    2016-01-01

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

  15. Ultrasound assisted in-situ formation of carbon/sulfur cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Pol, Vilas G.; Weng, Wei; Amine, Khalil

    2017-08-29

    A process of preparing an E-carbon nanocomposite includes contacting a porous carbon substrate with an E-containing material to form a mixture; and sonicating the mixture to form the E-carbon nanocomposite; where E is S, Se, Se.sub.xS.sub.y, or Te, x is greater than 0; and y is greater than 0.

  16. An X-ray photoelectron spectroscopy study of surface changes on brominated and sulfur-treated activated carbon sorbents during mercury capture: performance of pellet versus fiber sorbents.

    Science.gov (United States)

    Saha, Arindom; Abram, David N; Kuhl, Kendra P; Paradis, Jennifer; Crawford, Jenni L; Sasmaz, Erdem; Chang, Ramsay; Jaramillo, Thomas F; Wilcox, Jennifer

    2013-12-03

    This work explores surface changes and the Hg capture performance of brominated activated carbon (AC) pellets, sulfur-treated AC pellets, and sulfur-treated AC fibers upon exposure to simulated Powder River Basin-fired flue gas. Hg breakthrough curves yielded specific Hg capture amounts by means of the breakthrough shapes and times for the three samples. The brominated AC pellets showed a sharp breakthrough after 170-180 h and a capacity of 585 μg of Hg/g, the sulfur-treated AC pellets exhibited a gradual breakthrough after 80-90 h and a capacity of 661 μg of Hg/g, and the sulfur-treated AC fibers showed no breakthrough even after 1400 h, exhibiting a capacity of >9700 μg of Hg/g. X-ray photoelectron spectroscopy was used to analyze sorbent surfaces before and after testing to show important changes in quantification and oxidation states of surface Br, N, and S after exposure to the simulated flue gas. For the brominated and sulfur-treated AC pellet samples, the amount of surface-bound Br and reduced sulfur groups decreased upon Hg capture testing, while the level of weaker Hg-binding surface S(VI) and N species (perhaps as NH4(+)) increased significantly. A high initial concentration of strong Hg-binding reduced sulfur groups on the surface of the sulfur-treated AC fiber is likely responsible for this sorbent's minimal accumulation of S(VI) species during exposure to the simulated flue gas and is linked to its superior Hg capture performance compared to that of the brominated and sulfur-treated AC pellet samples.

  17. Preparation, characterization and application of modified macroporous carbon with Cosbnd N site for long-life lithium-sulfur battery

    Science.gov (United States)

    Jin, L. M.; He, F.; Cai, W. L.; Huang, J. X.; Liu, B. H.; Li, Z. P.

    2016-10-01

    A modified macroporous carbon (mMPC) containing Cosbnd Nx site is developed for sulfur retention to enhance cycleability of lithium-sulfur battery. Various nitrogen sites such as graphitic-N, pyrrolic-N, pyridinic-N, pyridinic-N oxide, and Cosbnd Nx are created during macropore formation. The sites without Co show limited polysulfide (PS) adsorption capability because nucleophilic N absorbs PS species via the weak interaction between N and Li in Nsbnd Lisbnd S bondage. The electrophilic Co(II) in Cosbnd Nx absorbs PS species via a strong interaction between S and Co in Ssbnd Co bond. The dual interaction of Cosbnd Nx site with Ssbnd Co and Nsbnd Lisbnd S bondages significantly enhances the PS adsorption. The resultant Li-S battery with the mMPC shows excellent cycleability, exhibiting a very low capacity degradation rate of 0.25 mAh g-1 per cycle after initial 20 cycles. A rate capacity as high as 660 mAh g-1 has been achieved after 300 cycles at 1 C charge-discharge rate.

  18. [Transformation characteristics of carbon, nitrogen, phosphorus and sulfur during thermal hydrolysis pretreatment of sludge with high solid content].

    Science.gov (United States)

    Zhuo, Yang; Han, Yun; Cheng, Yao; Peng, Dang-Cong; Li, Yu-You

    2015-03-01

    The transformation characteristics of carbon, nitrogen, phosphorus and sulfur in dewatering sludge from municipal wastewater treatment plant (WWTP) were investigated after thermal hydrolysis pretreatment at 165 degress C for 50 min. The results showed that the hydrolysis efficiency of VSS could reach as high as 43.35%, 54.36% of protein and 65.12% of carbohydrate were transferred to dissolved organics, respectively, and the main component of dissolved organic matter in hydrolysate was dissolved protein (52.18% ), 54.23% of insoluble organic nitrogen was turned into dissolved nitrogen and 22.13% of dissolved nitrogen in hydrolysate was converted to ammonia. The transformation rate of insoluble phosphorus was 30.52%. Dissolved phosphorus was mostly transformed to phosphate (79.84%) as phosphorus-accumulating bacteria cells were crushed. 50.03% of insoluble organic sulfur was hydrolyzed, and little change was detected in sulfide (0.50%). The analysis results of the organic compounds transformation are valuable for treatment of the thermal hydrolysis pretreated sludge with high solid content.

  19. Sulfur doping effects on the electronic and geometric structures of graphitic carbon nitride photocatalyst: insights from first principles.

    Science.gov (United States)

    Stolbov, Sergey; Zuluaga, Sebastian

    2013-02-27

    We present here results of our first-principles studies of the sulfur doping effects on the electronic and geometric structures of graphitic carbon nitride (g-C(3)N(4)). Using the ab initio thermodynamics approach combined with some kinetic analysis, we reveal the favorable S-doping configurations. By analyzing the valence charge densities of the doped and undoped systems, we find that sulfur partially donates its p(x)- and p(y)- electrons to the system with some back donation to the S p(z)-states. To obtain an accurate description of the excited electronic states, we calculate the electronic structure of the systems using the GW method. The band gap width calculated for g-C(3)N(4) is found to be equal to 2.7 eV, which is in agreement with experiment. We find the S doping causes a significant narrowing of the gap. Furthermore, the electronic states just above the gap become occupied upon doping, making the material a conductor. Analysis of the projected local density of states provides an insight into the mechanism underlying such changes in the electronic structure of g-C(3)N(4) upon S doping. Based on our results, we propose a possible explanation for the S-doping effect on the photocatalytic properties of g-C(3)N(4) observed in experiments.

  20. International politics of low carbon technology development: carbon capture and storage (CCS) in India

    OpenAIRE

    Kapila, Rudra Vidhumani

    2015-01-01

    This thesis explores the international political dynamics of developing low carbon technology. Specifically, Carbon Capture and Storage (CCS) technology as a climate mitigation strategy in a developing country context is examined. CCS is a technological solution that allows for the continued use of fossil fuels without the large amounts of associated CO2 emissions. This entails capturing the CO2 emitted from large point sources, such as a coal-fired power station, and transport...

  1. Method of preparing graphene-sulfur nanocomposites for rechargeable lithium-sulfur battery electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jun; Lemmon, John P; Yang, Zhenguo; Cao, Yuliang; Li, Xiaolin

    2015-04-07

    A method of preparing a graphene-sulfur nanocomposite for a cathode in a rechargeable lithium-sulfur battery comprising thermally expanding graphite oxide to yield graphene layers, mixing the graphene layers with a first solution comprising sulfur and carbon disulfide, evaporating the carbon disulfide to yield a solid nanocomposite, and grinding the solid nanocomposite to yield the graphene-sulfur nanocomposite. Rechargeable-lithium-sulfur batteries having a cathode that includes a graphene-sulfur nanocomposite can exhibit improved characteristics. The graphene-sulfur nanocomposite can be characterized by graphene sheets with particles of sulfur adsorbed to the graphene sheets. The sulfur particles have an average diameter of less than 50 nm.

  2. Using Demonstrations Involving Combustion and Acid-Base Chemistry to Show Hydration of Carbon Dioxide, Sulfur Dioxide, and Magnesium Oxide and Their Relevance for Environmental Climate Science

    Science.gov (United States)

    Shaw, C. Frank, III; Webb, James W.; Rothenberger, Otis

    2016-01-01

    The nature of acidic and basic (alkaline) oxides can be easily illustrated via a series of three straightforward classroom demonstrations for high school and general chemistry courses. Properties of carbon dioxide, sulfur dioxide, and magnesium oxide are revealed inexpensively and safely. Additionally, the very different kinetics of hydration of…

  3. Using Demonstrations Involving Combustion and Acid-Base Chemistry to Show Hydration of Carbon Dioxide, Sulfur Dioxide, and Magnesium Oxide and Their Relevance for Environmental Climate Science

    Science.gov (United States)

    Shaw, C. Frank, III; Webb, James W.; Rothenberger, Otis

    2016-01-01

    The nature of acidic and basic (alkaline) oxides can be easily illustrated via a series of three straightforward classroom demonstrations for high school and general chemistry courses. Properties of carbon dioxide, sulfur dioxide, and magnesium oxide are revealed inexpensively and safely. Additionally, the very different kinetics of hydration of…

  4. High-Resolution Infrared Spectroscopy of Carbon-Sulfur Chains: II. C_5S and SC_5S

    Science.gov (United States)

    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

  5. Multifunctional Free-Standing Gel Polymer Electrolyte with Carbon Nanofiber Interlayers for High-Performance Lithium-Sulfur Batteries.

    Science.gov (United States)

    Choi, Sinho; Song, Jianjun; Wang, Chengyin; Park, Soojin; Wang, Guoxiu

    2017-07-04

    Free-standing trimethylolpropane ethoxylate triacrylate gel polymer electrolyte is synthesized by a chemical cross-linking process and used as an electrolyte and separator membrane in lithium-sulfur batteries. The cross linked gel polymer electrolyte also exhibited a stable geometric size retention of 95 % at the high temperature of 130 °C. The as-prepared gel polymer electrolyte membrane with carbon nanofibers interlayer can effectively prevent polysulfide dissolution and shuttle effect, leading to significantly enhanced electrochemical properties, including high capacity and cycling stability, with an enhanced specific capacity of 790 mA h g(-1) after 100 cycles. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Plastidial metabolite transporters integrate photorespiration with carbon, nitrogen, and sulfur metabolism.

    Science.gov (United States)

    Eisenhut, Marion; Hocken, Nadine; Weber, Andreas P M

    2015-07-01

    Plant photorespiration is an essential prerequisite for oxygenic photosynthesis. This metabolic repair pathway bestrides four compartments, which poses the requirement for several metabolites transporters for pathway function. However, in contrast to the well-studied enzymatic steps of the core photorespiratory cycle, only few photorespiratory translocators have been identified to date. In this review, we give an overview of established and unknown plastidic transport proteins involved in photorespiration and intertwined nitrogen and sulfur metabolism, respectively. Furthermore, we discuss the evolutionary origin of the dicarboxylate translocators and the recently identified glycolate glycerate translocator.

  7. Determination of chlorine, sulfur and carbon in reinforced concrete structures by double-pulse laser-induced breakdown spectroscopy

    Science.gov (United States)

    Labutin, Timur A.; Popov, Andrey M.; Zaytsev, Sergey M.; Zorov, Nikita B.; Belkov, Mikhail V.; Kiris, Vasilii V.; Raikov, Sergey N.

    2014-09-01

    Accurate and reliable quantitative determination of non-metal corrosion agents in concrete is still an actual task of analytical use of LIBS. Two double-pulse LIBS systems were tested as a tool for the determination of chlorine, sulfur and carbon in concretes. Both systems had collinear configuration; a laboratory setup was equipped with an ICCD and two lasers (355/532 nm + 540 nm), but a CCD was a detector for a mobile system with one laser (1064 nm). Analytical lines of Cl I at 837.59 nm, S I at 921 nm and C I at 247.86 nm were used to plot calibration curves. Optimal interpulse delays for the laboratory setup were 4 μs for chlorine and 2.8 μs for carbon, while an interpulse delay of 2 μs was optimal for chlorine and sulfur determination with the mobile system. We suggested the normalization of the Cl I line at 837.59 nm to the Mg II line at 279.08 nm (visible at 837.23 nm in the third order) to compensate for pulse-to-pulse fluctuations of chlorine lines. It provided the decrease of the detection limit of chlorine from 400 ppm to 50 ppm. Therefore, we reported that LIBS can be used to determine main corrosive active substances under ambient conditions in concrete below critical threshold values. Moreover, the application of the mobile system for in-situ qualitative assessment of corrosion way of a steel cage of a swimming pool dome was also demonstrated. It was found that chloride corrosion due to the disinfection of water was the main way for corrosion of the open part steel and the steel rebar inside the concrete.

  8. Simultaneous removal of sulfur dioxide and polycyclic aromatic hydrocarbons from incineration flue gas using activated carbon fibers.

    Science.gov (United States)

    Liu, Zhen-Shu; Li, Wen-Kai; Hung, Ming-Jui

    2014-09-01

    Incineration flue gas contains polycyclic aromatic hydrocarbons (PAHs) and sulfur dioxide (SO2). The effects of SO2 concentration (0, 350, 750, and 1000 ppm), reaction temperature (160, 200, and 280 degrees C), and the type of activated carbon fibers (ACFs) on the removal of SO2 and PAHs by ACFs were examined in this study. A fluidized bed incinerator was used to simulate practical incineration flue gas. It was found that the presence of SO2 in the incineration flue gas could drastically decrease removal of PAHs because of competitive adsorption. The effect of rise in the reaction temperature from 160 to 280 degrees C on removal of PAHs was greater than that on SO2 removal at an SO2 concentration of 750 ppm. Among the three ACFs studied, ACF-B, with the highest microporous volume, highest O content, and the tightest structure, was the best adsorbent for removing SO2 and PAHs when these gases coexisted in the incineration flue gas. Implications: Simultaneous adsorption of sulfur dioxide (SO2) and polycyclic aromatic hydrocarbons (PAHs) emitted from incineration flue gas onto activated carbon fibers (ACFs) meant to devise a new technique showed that the presence of SO2 in the incineration flue gas leads to a drastic decrease in removal of PAHs because of competitive adsorption. Reaction temperature had a greater influence on PAHs removal than on SO2 removal. ACF-B, with the highest microporous volume, highest O content, and tightest structure among the three studied ACFs, was found to be the best adsorbent for removing SO2 and PAHs.

  9. Self-assembly sandwiches of reduced graphene oxide layers with zeolitic-imidazolate-frameworks-derived mesoporous carbons as polysulfides reservoirs for lithium-sulfur batteries

    Science.gov (United States)

    Tan, Yingbin; Jia, Zhiqing; Lou, Peili; Cui, Zhonghui; Guo, Xiangxin

    2017-02-01

    Confinement of sulfur and alleviation of the polysulfides dissolution are the key issues for development of high-performance lithium-sulfur (Li-S) batteries. Here, we report self-assembly sandwiches composed of zeolitic-imidazolate-frameworks (ZIF-8)-derived mesoporous carbons (ZIF-8(C)) in between reduced graphene oxide (rGO) layers, which are filled with sulfurs inside and coated with poly(3, 4-ethylenedioxythiophene) (PEDOT) outside (noted as P@rGO/ZIF-8(C)). During the synthesis process, the rGO layers stabilize the structure of ZIF-8 nanocrystals to obtain large specific surface area and high electric conductivity of mesoporous materials (rGO/ZIF-8(C)), ensuring accommodation of a large amount of sulfur and the efficient utilization of the confined sulfur. The mesoporous rGO/ZIF-8(C), PEDOT and N-doping provide physical absorption and chemical binding to the polysulfides during cycles. Consequently, the Li-S batteries with the composite cathodes exhibit the high capacity of 1308 mAh g-1 and 865 mAh g-1 at 0.2 C and 1 C, respectively, and a very low capacity fading of 0.03% per cycle after 500 reversible cycles at 1 C rate. The results indicate that the P@rGO/ZIF-8(C)-S composite cathode may offer a feasible strategy for construction of sulfur cathodes for high-performance Li-S batteries.

  10. How does the exchange of one oxygen atom with sulfur affect the catalytic cycle of carbonic anhydrase?

    Science.gov (United States)

    Schenk, Stephan; Kesselmeier, Jürgen; Anders, Ernst

    2004-06-21

    We have extended our investigations of the carbonic anhydrase (CA) cycle with the model system [(H(3)N)(3)ZnOH](+) and CO(2) by studying further heterocumulenes and catalysts. We investigated the hydration of COS, an atmospheric trace gas. This reaction plays an important role in the global COS cycle since biological consumption, that is, uptake by higher plants, algae, lichens, and soil, represents the dominant terrestrial sink for this gas. In this context, CA has been identified by a member of our group as the key enzyme for the consumption of COS by conversion into CO(2) and H(2)S. We investigated the hydration mechanism of COS by using density functional theory to elucidate the details of the catalytic cycle. Calculations were first performed for the uncatalyzed gas phase reaction. The rate-determining step for direct reaction of COS with H(2)O has an energy barrier of deltaG=53.2 kcal mol(-1). We then employed the CA model system [(H(3)N)(3)ZnOH](+) (1) and studied the effect on the catalytic hydration mechanism of replacing an oxygen atom with sulfur. When COS enters the carbonic anhydrase cycle, the sulfur atom is incorporated into the catalyst to yield [(H(3)N)(3)ZnSH](+) (27) and CO(2). The activation energy of the nucleophilic attack on COS, which is the rate-determining step, is somewhat higher (20.1 kcal mol(-1) in the gas phase) than that previously reported for CO(2). The sulfur-containing model 27 is also capable of catalyzing the reaction of CO(2) to produce thiocarbonic acid. A larger barrier has to be overcome for the reaction of 27 with CO(2) compared to that for the reaction of 1 with CO(2). At a well-defined stage of this cycle, a different reaction path can emerge: a water molecule helps to regenerate the original catalyst 1 from 27, a process accompanied by the formation of thiocarbonic acid. We finally demonstrate that nature selected a surprisingly elegant and efficient group of reactants, the [L(3)ZnOH](+)/CO(2)/H(2)O system, that helps

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

    Science.gov (United States)

    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.

  12. Strong Lithium Polysulfide Chemisorption on Electroactive Sites of Nitrogen-Doped Carbon Composites For High-Performance Lithium–Sulfur Battery Cathodes

    Energy Technology Data Exchange (ETDEWEB)

    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.

  13. Strong Lithium Polysulfide Chemisorption on Electroactive Sites of Nitrogen-Doped Carbon Composites For High-Performance Lithium-Sulfur Battery Cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Song, Jiangxuan [Pennsylvania State Univ., State College, PA (United States). Dept. of Mechanical and Nuclear Engineering; Gordin, Mikhail L. [Pennsylvania State Univ., State College, PA (United States). Dept. of Mechanical and Nuclear Engineering; Xu, Terrence [Pennsylvania State Univ., State College, PA (United States). Dept. of Mechanical and Nuclear Engineering; Chen, Shuru [Pennsylvania State Univ., State College, PA (United States). Dept. of Mechanical and Nuclear Engineering; Yu, Zhaoxin [Pennsylvania State Univ., State College, PA (United States). Dept. of Mechanical and Nuclear Engineering; Sohn, Hiesang [Pennsylvania State Univ., State College, PA (United States). Dept. of Mechanical and Nuclear Engineering; Lu, Jun [Argonne National Lab. (ANL), Argonne, IL (United States). Chemical Sciences and Engineering Div.; Ren, Yang [Argonne National Lab. (ANL), Argonne, IL (United States). X-ray Science Div.; Duan, Yuhua [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States); Wang, Donghai [Pennsylvania State Univ., State College, PA (United States). Dept. of Mechanical and Nuclear Engineering

    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.

  14. Reconstruction of multidimensional carbon hosts with combined 0D, 1D and 2D networks for enhanced lithium-sulfur batteries

    Science.gov (United States)

    Li, S. H.; Xia, X. H.; Wang, Y. D.; Wang, X. L.; Tu, J. P.

    2017-02-01

    It is a core task to find solutions to suppress the "shuttle effect" of polysulfides and improve high rate capability at the sulfur cathode of lithium sulfur batteries. Herein we first time propose a concept of multileveled blocking "dams" to suppress the diffusion of polysulfides. We report a facile and effective strategy to construct multidimensional conductive carbon hosts for accommodation of active sulfur. Multidimensional ternary carbon networks (MTCNs) with 0D nanospheres, 1D nanotubes and 2D nanoflakes are organically combined together to provide multileveled conductive channels to reserve active sulfur and promote stable sustained reactions. In the light of enhanced conductivity and multileveled blocking "dams" for polysulfides, the designed MTCNs/S cathode has been demonstrated with noticeable improvement in discharge capacity (1472 mAh g-1 at 0.l C) and long-term cycling stability (65% retention at 5.0 C after 500 cycles). Our research may provide a new insight in the gradient blocking of polysulfides with the help of multidimensional carbon networks.

  15. Massive impact-induced release of carbon and sulfur gases in the early Earth's atmosphere

    Science.gov (United States)

    Marchi, S.; Black, B. A.; Elkins-Tanton, L. T.; Bottke, W. F.

    2016-09-01

    Recent revisions to our understanding of the collisional history of the Hadean and early-Archean Earth indicate that large collisions may have been an important geophysical process. In this work we show that the early bombardment flux of large impactors (>100 km) facilitated the atmospheric release of greenhouse gases (particularly CO2) from Earth's mantle. Depending on the timescale for the drawdown of atmospheric CO2, the Earth's surface could have been subject to prolonged clement surface conditions or multiple freeze-thaw cycles. The bombardment also delivered and redistributed to the surface large quantities of sulfur, one of the most important elements for life. The stochastic occurrence of large collisions could provide insights on why the Earth and Venus, considered Earth's twin planet, exhibit radically different atmospheres.

  16. 脱汞载硫活性炭的制备及表征%Preparation and Characterization of Sulfur-loaded Activated Carbon for Mercury Removal

    Institute of Scientific and Technical Information of China (English)

    范莉莉; 刘晓玲; 刘霞

    2016-01-01

    In this paper, the preparation of sulfur-loaded activated carbon was studied,Taixi Coal Based-Activated Carbon used as the carrier. Some factors were discussed such as the carbon tetrachloride adsorption, S/C and dipping time on the influence of amount of sulfur. Meantime the structure of the prepared carrier was characterized by BET. The results showed that:when the carbon tetrachloride adsorption value was 60%, S/C was 14%, and the time was 24h, the sulfur content of the prepared activated carbon was 10.89%, and the solvent recovery rate was 90%.%本文以太西煤基活性炭为载体,研究了载硫活性炭的制备工艺,并探讨了四氯化碳吸附值、S/C和浸渍时间对载硫量的影响,同时采用BET表征对制备的载硫体的结构进行了表征。结果表明:当四氯化碳吸附值为60%,S/C为14%,浸渍时间为24h时,所制备的载硫活性炭载硫量最高为10.89%,且溶剂回收率高达90%。

  17. Carbon and sulfur cycling by microbial communities in a gypsum-treated oil sands tailings pond.

    Science.gov (United States)

    Ramos-Padrón, Esther; Bordenave, Sylvain; Lin, Shiping; Bhaskar, Iyswarya Mani; Dong, Xiaoli; Sensen, Christoph W; Fournier, Joseph; Voordouw, Gerrit; Gieg, Lisa M

    2011-01-15

    Oil sands tailings ponds receive and store the solid and liquid waste from bitumen extraction and are managed to promote solids densification and water recycling. The ponds are highly stratified due to increasing solids content as a function of depth but can be impacted by tailings addition and removal and by convection due to microbial gas production. We characterized the microbial communities in relation to microbial activities as a function of depth in an active tailings pond routinely treated with gypsum (CaSO(4)·2H(2)O) to accelerate densification. Pyrosequencing of 16S rDNA gene sequences indicated that the aerobic surface layer, where the highest level of sulfate (6 mM) but no sulfide was detected, had a very different community profile than the rest of the pond. Deeper anaerobic layers were dominated by syntrophs (Pelotomaculum, Syntrophus, and Smithella spp.), sulfate- and sulfur-reducing bacteria (SRB, Desulfocapsa and Desulfurivibrio spp.), acetate- and H(2)-using methanogens, and a variety of other anaerobes that have been implicated in hydrocarbon utilization or iron and sulfur cycling. The SRB were most abundant from 10 to 14 mbs, bracketing the zone where the sulfate reduction rate was highest. Similarly, the most abundant methanogens and syntrophs identified as a function of depth closely mirrored the fluctuating methanogenesis rates. Methanogenesis was inhibited in laboratory incubations by nearly 50% when sulfate was supplied at pond-level concentrations suggesting that in situ sulfate reduction can substantially minimize methane emissions. Based on our data, we hypothesize that the emission of sulfide due to SRB activity in the gypsum treated pond is also limited due to its high solubility and oxidation in surface waters.

  18. Reduced graphene oxide with ultrahigh conductivity as carbon coating layer for high performance sulfur@reduced graphene oxide cathode

    Science.gov (United States)

    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.

  19. Carbon Dioxide Management on the International Space Station

    Science.gov (United States)

    Burlingame, Katie

    2016-01-01

    The International Space Station (ISS) is a manned laboratory operating in orbit around the Earth that was built and is currently operated by several countries across the world. The ISS is a platform for novel scientific research as well as a testbed for technologies that will be required for the next step in space exploration. In order for astronauts to live on ISS for an extended period of time, it is vital that on board systems consistently provide a clean atmosphere. One contaminant that must be removed from the atmosphere is carbon dioxide (CO2). CO2 levels on ISS are higher than those on Earth and can cause crew members to experience symptoms such as headaches, lethargy and mental slowness. A variety of systems exist on ISS to remove carbon dioxide, including adsorbent technologies which can be reused and testbed technologies for future space vehicles.

  20. Impact of sulfuric and nitric acids on carbonate dissolution, and the associated deficit of CO2 uptake in the upper-middle reaches of the Wujiang River, China

    Science.gov (United States)

    Huang, Qi-bo; Qin, Xiao-qun; Liu, Peng-yu; Zhang, Lian-kai; Su, Chun-tian

    2017-08-01

    Carbonate weathering and the CO2 consumption in karstic area are extensive affected by anthropogenic activities, especially sulfuric and nitric acids usage in the upper-middle reaches of Wujiang River, China. The carbonic acid would be substituted by protons from sulfuric and nitric acids which can be reduce CO2 absorption. Therefore, The goal of this study was to highlight the impacts of sulfuric and nitric acids on carbonate dissolution and the associated deficit of CO2 uptaking during carbonate weathering. The hydrochemistries and carbon isotopic signatures of dissolved inorganic carbon from groundwater were measured during the rainy season (July; 41 samples) and post-rainy season (October; 26 samples). Our results show that Ca2 + and Mg2 + were the dominant cations (55.87-98.52%), and HCO3- was the dominant anion (63.63-92.87%). The combined concentrations of Ca2 + and Mg2 + commonly exceeded the equivalent concentration of HCO3-, with calculated [Ca2 + + Mg2 +]/[HCO3-] equivalent ratios of 1.09-2.12. The mean measured groundwater δ13CDIC value (- 11.38‰) was higher than that expected for carbonate dissolution mediated solely by carbonic acid (- 11.5‰), and the strong positive correlation of these values with [SO42 - + NO3-]/HCO3- showed that additional SO42 - and NO3- were required to compensate for this cation excess. Nitric and sulfuric acids are, therefore, suggested to have acted as the additional proton-promoted weathering agents of carbonate in the region, alongside carbonic acid. The mean contribution of atmospheric/pedospheric CO2 to the total aquatic HCO3- decreased by 15.67% (rainy season) and 14.17% (post-rainy season) due to the contributions made by these acids. The annual mean deficit of soil CO2 uptake by carbonate weathering across the study area was 14.92%, which suggests that previous workers may have overestimated the absorption of CO2 by carbonate weathering in other karstic areas worldwide.

  1. A novel three-dimensional sulfur/graphene/carbon nanotube composite prepared by a hydrothermal co-assembling route as binder-free cathode for lithium–sulfur batteries

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Guanghui; Wang, Gang [Northwest University, National Key Laboratory of Photoelectric Technology and Functional Materials (Culture Base), National Photoelectric Technology and Functional Materials & Application International Cooperation Base, Physics Department, Institute of Photonics & Photon-Technology (China); Wang, Hui, E-mail: huiwang@nwu.edu.cn [Northwest University, Key Laboratory of Synthetic and Natural Functional Molecule Chemistry (Ministry of Education), College of Chemistry & Materials Science (China); Bai, Jintao, E-mail: jintaobai@sina.cn, E-mail: baijt@nwu.edu.cn [Northwest University, National Key Laboratory of Photoelectric Technology and Functional Materials (Culture Base), National Photoelectric Technology and Functional Materials & Application International Cooperation Base, Physics Department, Institute of Photonics & Photon-Technology (China)

    2015-01-15

    A novel sulfur/graphene/carbon nanotube (S/GN/CNT) composite was successfully prepared by a facile hydrothermal co-assembling route. When used as cathode for lithium–sulfur battery, the S/GN/CNT composite can be pressed directly onto nickel foam without binder and conductive additive, thereby simplifying the manufacturing process. The resulting S/GN/CNT composite exhibited high and stable-specific discharge capacities of 670 mAh g{sup −1} after 80 cycles at 0.2 C and good rate capability. This enhanced electrochemical performance could be attributed to the combinative effects of GN and CNT, which not only function as a flexible conductive matrix, favoring the ion transport and electrolyte diffusion, but also for provide a porous three-dimensional architecture with open channels to effectively confine the soluble polysulfides.

  2. A novel three-dimensional sulfur/graphene/carbon nanotube composite prepared by a hydrothermal co-assembling route as binder-free cathode for lithium-sulfur batteries

    Science.gov (United States)

    Yuan, Guanghui; Wang, Gang; Wang, Hui; Bai, Jintao

    2015-01-01

    A novel sulfur/graphene/carbon nanotube (S/GN/CNT) composite was successfully prepared by a facile hydrothermal co-assembling route. When used as cathode for lithium-sulfur battery, the S/GN/CNT composite can be pressed directly onto nickel foam without binder and conductive additive, thereby simplifying the manufacturing process. The resulting S/GN/CNT composite exhibited high and stable-specific discharge capacities of 670 mAh g-1 after 80 cycles at 0.2 C and good rate capability. This enhanced electrochemical performance could be attributed to the combinative effects of GN and CNT, which not only function as a flexible conductive matrix, favoring the ion transport and electrolyte diffusion, but also for provide a porous three-dimensional architecture with open channels to effectively confine the soluble polysulfides.

  3. Temperature and Carbon Assimilation Regulate the Chlorosome Biogenesis in Green Sulfur Bacteria

    CERN Document Server

    Tang, Joseph Kuo-Hsiang; Pingali, Sai Venkatesh; Enriquez, Miriam M; Huh, Joonsuk; Frank, Harry A; Urban, Volker S; Aspuru-Guzik, Alan

    2013-01-01

    Green photosynthetic bacteria adjust the structure and functionality of the chlorosome - the light absorbing antenna complex - in response to environmental stress factors. The chlorosome is a natural self-assembled aggregate of bacteriochlorophyll (BChl) molecules. In this study we report the regulation of the biogenesis of the Chlorobaculum tepidum chlorosome by carbon assimilation in conjunction with temperature changes. Our studies indicate that the carbon source and thermal stress culture of Cba. tepidum grows slower and incorporates less BChl c in the chlorosome. Compared with the chlorosome from other cultural conditions we investigated, the chlorosome from the carbon source and thermal stress culture displays: (a) smaller cross-sectional radius and overall size; (b) simplified BChl c homologues with smaller side chains; (c) blue-shifted Qy absorption maxima and (d) a sigmoid-shaped circular dichroism (CD) spectra. Using a theoretical model we analyze how the observed spectral modifications can be assoc...

  4. [Microbiological processes of the carbon and sulfur cycle in cold methane seeps in the North Atlantic].

    Science.gov (United States)

    Pimenov, N V; Savvichev, A S; Rusanov, I I; Lein, A Iu; Ivanov, M V

    2000-01-01

    Functioning of microbial communities in surface sediments of the Haakon Mosby underwater mud volcano (lat. 72 degrees N) and in gas seepage fields of the Vestnesa Ridge was investigated using Mir-1 and Mir-2 deep-sea submersibles during the 40th expedition of the research vessel Academician Mstislav Keldysh. Large areas of sedimentary deposits of the Haakon Mosby mud volcano (HMMV) and pockmarks of the Vestnesa Ridge (VR) are covered with bacterial mats 0.1 to 0.5 cm thick. The microbial community making up bacterial mats of the HMMV was predominated by large filamentous bacteria with filaments measuring up to 100 microns in length and 2 to 8 microns in width. The occurrence of rosettes allowed the observed filamentous bacteria to be referred to the morphologically similar genera Leucothrix or Thiothrix. Three morphological types of filamentous bacteria were identified in bacterial mats covering VR pockmarks. Filaments of type one are morphologically similar with representatives of the genera Thioploca or Desmanthos. Type two filaments had numerous inclusions of sulfur and resembled representatives of the genus Thiothrix. The third morphological type was constituted by single filaments made up of tightly connected disk-like cells and can, apparently, be assigned to the genus Beggiatoa. The rates of methane oxidation (up to 1570 microliters C/(dm3 day)) and sulfate reduction (up to 17 mg S/(dm3 day)) measured in surface sediments of HMMV and VR were close to the maximum rates of these processes observed in badly polluted regions of the northwestern shelf of the Black Sea. High rates of microbiological processes correlated with the high number of bacteria. The rate of methane production in sediments studied was notably lower and ranged from 0.1 to 3.5 microliters CH4/(dm3 day). Large areas of the HMMV caldera were populated by pogonophoras, represented by the two species, Sclerolinum sp. and Oligobrachia sp. The mass development of Sclerolinum sp. in the HMMV caldera

  5. Novel CoS2 embedded carbon nanocages by direct sulfurizing metal-organic frameworks for dye-sensitized solar cells

    Science.gov (United States)

    Cui, Xiaodan; Xie, Zhiqiang; Wang, Ying

    2016-06-01

    Owing to its excellent electrocatalytic properties, cobalt disulfide (CoS2) is regarded as a promising counter electrode (CE) material for dye-sensitized solar cells (DSSCs). However, hindered by its relatively poor electrical conductivity and chemical instability, it remains a challenge to apply it into high-performance DSSCs. In this work, we have developed novel CoS2 embedded carbon nanocages as a CE in DSSCs, using ZIF-67 (zeolitic imidazolate framework 67, Co(mim)2, mim = 2-methylimidolate) as a template. The CoS2 samples sulfurized for different time lengths are prepared through a facile solution process. It is found that the sulfurization time can be optimized to maximize the DSSC efficiency and the DSSC based on the CoS2 embedded carbon nanocages sulfurized for 4 hours exhibits the highest photovoltaic conversion efficiency (PCE) of 8.20%, higher than those of DSSCs consisting of other CoS2 CEs and Pt-based DSSC (7.88%). The significantly improved DSSC PCE is contributed by the synergic effect of inner CoS2 nanoparticles and an amorphous carbon matrix, leading to a CE with high catalytic activity, good electrical conductivity and excellent durability. This study demonstrates that the CE based on inexpensive CoS2 embedded carbon nanocages is a prospective substitute to expensive platinum and provides a new approach for commercializing high-efficiency DSSCs.

  6. Depositional environments inferred from variations of calcium carbonate, organic carbon, and sulfide sulfur: a core from southeastern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Paropkari, A; Iyer, S.D.; Chauhan, O.S; PrakashBabu, C.

    The variations in CaCO3 and organic carbon and their inter-relationship in a core from the southeastern Arabian Sea (water depth 2,212 m) have been used to demarcate the Holocene/Pleistocene boundary; an increased terrigenous deposition during Late...

  7. Method and system for capturing carbon dioxide and/or sulfur dioxide from gas stream

    Science.gov (United States)

    Chang, Shih-Ger; Li, Yang; Zhao, Xinglei

    2014-07-08

    The present invention provides a system for capturing CO.sub.2 and/or SO.sub.2, comprising: (a) a CO.sub.2 and/or SO.sub.2 absorber comprising an amine and/or amino acid salt capable of absorbing the CO.sub.2 and/or SO.sub.2 to produce a CO.sub.2- and/or SO.sub.2-containing solution; (b) an amine regenerator to regenerate the amine and/or amino acid salt; and, when the system captures CO.sub.2, (c) an alkali metal carbonate regenerator comprising an ammonium catalyst capable catalyzing the aqueous alkali metal bicarbonate into the alkali metal carbonate and CO.sub.2 gas. The present invention also provides for a system for capturing SO.sub.2, comprising: (a) a SO.sub.2 absorber comprising aqueous alkali metal carbonate, wherein the alkali metal carbonate is capable of absorbing the SO.sub.2 to produce an alkali metal sulfite/sulfate precipitate and CO.sub.2.

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

    Science.gov (United States)

    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.

  9. Evolution of Sulfur Isotopes and Oceanic Oxygenation Recorded in a Neoproterozoic Cap Carbonate From the Chaidam Block, China

    Science.gov (United States)

    Shen, B.; Xiao, S.; Kaufman, A.; Zhou, C.

    2006-12-01

    Neoproterozoic successions in the Chaidam Block, northwestern China, include the Hongtiegou Formation, which consists of a 20-meter thick, reddish diamictite with widespread dropstones and outsized clasts. The age of the Hongtiegou diamictite is unknown, but recent biostratigraphic correlations support a Neoproterozoic assignment. The glacial deposit is immediately overlain by a 5-meter thick carbonate of the basal Zhoujieshan Formation, which we interpret as a classic post-glacial cap carbonate. However, carbon isotope compositions of samples from this unit are near zero or slightly positive (up to ~ 2‰), which contrasts with the strongly negative (ca. -5‰) values recorded in the basal portions of most other post-glacial Neoproterozoic caps. Trace sulfate concentrations in samples of the carbonate are notably high, with an average of 366 ± 266 ppm. In the lower 2.5 meters of the Zhoujieshan cap (stage I) sulfur isotope compositions of both carbonate associated sulfate (CAS) and sulfides isolated from the same sample are indistinguishable from each other, and rise in concert by over 10% to values around +22‰. Above this level (stage II), 34S abundances of sulfides continue to increase to a peak of +27‰, but CAS values fall back to ~15‰. As a result isotopic differences between sulfides and sulfates are near zero in stage I and around 10% in stage II. The evolution of both systems in the lower half of the deposit suggests that seawater sulfate must have evolved to progressively heavier 34S compositions, and that sulfate in pore waters ¨C where sulfate reducing bacteria were active ¨C was quantitatively reduced to pyrite. This might result from the progressive distillation of sulfate from seawater by an enhanced rain of carbonate, in addition to bacterial reduction of sulfate, in the glacial aftermath. The anomalous isotope systematics of stage II are difficult to model, but might signal a new source and higher abundances of oceanic sulfate, based on

  10. Effects of temperature on the heterogeneous oxidation of sulfur dioxide by ozone on calcium carbonate

    Directory of Open Access Journals (Sweden)

    L. Y. Wu

    2011-07-01

    Full Text Available The heterogeneous oxidation of sulfur dioxide by ozone on CaCO3 was studied as a function of temperature (230 to 298 K at ambient pressure. Oxidation reactions were followed in real time using diffuse reflectance infrared Fourier transform spectrometry (DRIFTS to obtain kinetic and mechanistic data. From the analysis of the spectral features, the formation of sulfate was identified on the surface in the presence of O3 and SO2 at different temperatures from 230 to 298 K. The results showed that the heterogeneous oxidation and the rate of sulfate formation were sensitive to temperature. An interesting stage-transition region was observed at temperatures ranging from 230 to 257 K, but it became ambiguous gradually above 257 K. The reactive uptake coefficients at different temperatures from 230 to 298 K were acquired for the first time, which can be used directly in atmospheric chemistry modeling studies to predict the formation of secondary sulfate aerosol in the troposphere. Furthermore, the rate of sulfate formation had a turning point at about 250 K. The sulfate concentration at 250 K was about twice as large as that at 298 K. The rate of sulfate formation increased with decreasing temperature at temperatures above 250 K, while there is a contrary temperature effect at temperatures below 250 K. The activation energy for heterogeneous oxidation at temperatures from 245 K to 230 K was determined to be 14.63 ± 0.20 kJ mol−1. A mechanism for the temperature dependence was proposed and the atmospheric implications were discussed.

  11. Carbon- and Sulfur-bearing Minerals in the Martian Meteorite ALH 84001

    Science.gov (United States)

    Romanek, C. S.; Thomas, K. L.; Gibson, E. K., Jr.; McKay, D. S.; Socki, R. A.

    1995-09-01

    Unusual carbonate minerals in ALH 84001 [1] provide insights into surficial processes that may have occurred on Mars, but despite detailed geochemical studies [2-4] carbonate petrogenesis has yet to be fully-characterized. High-resolution TEM and SEM analyses were performed on C- and S-bearing mineral grains to better constrain the nature and timing of carbonate mineralization events. Morphological elements: C- and S-bearing minerals in ALH 84001 commonly occur as spheroidal aggregates or fine-grained vug-filling structures. Spheroids are either orange or black, ~150 micrometers (+/- 50 micrometers) in diameter and highly-flattened (10-30 micrometers thick). Orange spheroids have limpid amber-colored cores and white to translucent mantles which are sometimes bound by thin black rims (White mantles of the orange spheroids are composed of nearly pure MgCO3 (Harvey and McSween (1995) LPS XXVI, 555. [5] Marshall D. J. (1988) Cathodoluminescence of Geologic Materials, Unwin Hyman. [6] Mucci A. and Morse J. W. (1990) Aquatic Sci., 3, 217. [7] Mozley P. S. and Carothers W. W. (1992) J. Sed. Petrol., 62, 681.

  12. Interfacial Reaction Dependent Performance of Hollow Carbon Nanosphere – Sulfur Composite as a Cathode for Li-S Battery

    OpenAIRE

    Zheng, Jianming; Yan, Pengfei; Gu, Meng; Wagner, Michael J.; Hays, Kevin A.; Chen, Junzheng; Li, Xiaohong; Wang, Chongmin; Zhang, Ji-Guang; Liu, Jun; Xiao, Jie

    2015-01-01

    Lithium-sulfur (Li-S) battery is a promising energy storage system due to its high energy density, cost effectiveness, and environmental friendliness of sulfur. However, there are still a number of technical challenges, such as low Coulombic efficiency and poor long-term cycle life, impeding the commercialization of Li-S battery. The electrochemical performance of Li-S battery is closely related with the interfacial reactions occurring between hosting substrate and active sulfur species, whic...

  13. Nitrogen and sulfur co-doped carbon dots for highly selective and sensitive detection of Hg (II) ions.

    Science.gov (United States)

    Li, Libo; Yu, Bin; You, Tianyan

    2015-12-15

    Nitrogen and sulfur co-doped carbon dots (N,S/C-dots) with high fluorescence quantum yields (FLQY, 25%) was successfully synthesized by a one-step microwave-assisted method. In comparison with nitrogen doped C-dots (N/C-dots) prepared using the same method, the resulting N,S/C-dots featured small particle size, uniform surface state, insensitive FL properties to excitation wavelengths and environmental conditions, negligible cytotoxicity and excellent biocompatibility. Simultaneous doping of N and S effectively promoted electron-transfer and coordination interaction between N,S/C-dots and Hg(2+). Thus, when used as fluorescence probe for Hg(2+) label-free detection, the resulting N,S/C-dots showed good detection sensitivity and ion selectivity. The limit of detection was 2 μM; among 15 metal ions investigated, only Fe(3+) showed interference to the Hg(2+) detection. Fortunately, this interference could be effectively shielded using a chelating agent sodium hexametaphoshpate. The applicability of N,S/C-dots as fluorescence probe for Hg(2+) detection in lake water and tap water was demonstrated. Finally, based on its favorable features of negligible cytotoxicity and excellent biocompatibility, the N,S/C-dots were successfully applied to probe Hg(2+) in living cells, which broaden its application in biological system.

  14. Sources and Cycling of Dissolved Organic Matter in the Sacramento - San Joaquin Delta, California, Using Carbon, Nitrogen, and Sulfur Isotopes

    Science.gov (United States)

    Silva, S. R.; Kendall, C.; Doctor, D. H.; Bergamaschi, B. A.; Fram, M. S.; Kraus, T.

    2006-12-01

    An important water quality concern of the Sacramento-San Joaquin Delta portion of the Calfed Bay-Delta restoration program is the generation of disinfection byproducts (DBP) as a result of chlorination or ozonation of San Francisco Bay Delta drinking water. One means of reducing DBPs is through monitoring and control of water sources from the various delta environments entering the California aqueduct with the objective of reducing the quantity of dissolved organic matter (DOM) and lowering the fraction with the highest DBP formation potential. The purpose of this study is to investigate the use of carbon, nitrogen, and sulfur isotopic compositions of DOM to help differentiate DOM sources and interpret seasonal variations. For this purpose, water samples collected from five general delta environments between December 1999 and June 2001 were analyzed for d13C, d15N, and d34S of DOM as well as for various chemical and optical properties. Monthly averages of d13C and d15N values for DOM retained on XAD-4 and XAD-8 resins show distinctive compositions for island drain and wetland environments throughout the year which reflect the agriculturally- related terrestrial sources of DOM from island drains, and the aquatic sources for the wetland areas. On average, the d13C values of DOM from open water (flooded island) environments, channels, and the Sacramento River water are indistinguishable from each other from spring through fall and show a progressive increase in d13C, which is likely controlled by the cycle of aquatic production through the growing season. The isotopic values from these environments diverge in the winter reflecting a change in the relative importance of the various mechanisms (sources and cycling) controlling DOM production. Sulfur isotopes show both the effects of sulfate reduction and the influence of seawater sulfate on local biota. The d13C, d15N, and d34S values show a number of correlations related to both environment and season, reflecting the

  15. Corrosion Inhibition of Carbon Steel In Sulfuric Acid by Sodium Caprylate

    Directory of Open Access Journals (Sweden)

    Saad Ghareba

    2016-01-01

    Full Text Available The interaction of a sodium salt of octanoic acid, sodium caprylate (SC, with a carbon steel (CS surface was investigated, using range of experimental techniques. It was shown that SC acts as a good CS general corrosion inhibitor, yielding a maximum corrosion inhibition efficiency of 77%. This high inhibition efficiency is maintained even at higher temperatures. It was determined that SC inhibits both partial corrosion reactions, and can thus be considered to be a mixed-type inhibitor. The adsorption of SC on the CS surface was described by the Langmuir adsorption isotherm. It was found that this process is spontaneous, irreversible and driven by the entropy gain. The CS surface morphology was studied by SEM and it was demonstrated that SC is a very effective general corrosion inhibitor of CS. This also was confirmed by contact angle measurements which showed that the CS surface became more hydrophobic when the SC was added to the solution.

  16. 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

    Science.gov (United States)

    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.

  17. Geochemical modeling of iron, sulfur, oxygen and carbon in a coastal plain aquifer

    Science.gov (United States)

    Brown, C.J.; Schoonen, M.A.A.; Candela, J.L.

    2000-01-01

    Fe(III) reduction in the Magothy aquifer of Long Island, NY, results in high dissolved-iron concentrations that degrade water quality. Geochemical modeling was used to constrain iron-related geochemical processes and redox zonation along a flow path. The observed increase in dissolved inorganic carbon is consistent with the oxidation of sedimentary organic matter coupled to the reduction of O2 and SO4/2- in the aerobic zone, and to the reduction of SO4/2- in the anaerobic zone; estimated rates of CO2 production through reduction of Fe(III) were relatively minor by comparison. The rates of CO2 production calculated from dissolved inorganic carbon mass transfer (2.55 x 10-4 to 48.6 x 10-4 mmol 1-1 yr-1) generally were comparable to the calculated rates of CO2 production by the combined reduction of O2, Fe(III) and SO4/2- (1.31 x 10-4 to 15 x 10-4 mmol 1-1 yr-1). The overall increase in SO4/2- concentrations along the flow path, together with the results of mass-balance calculations, and variations in ??34S values along the flow path indicate that SO4/2- loss through microbial reduction is exceeded by SO4/2- gain through diffusion from sediments and through the oxidation of FeS2. Geochemichal and microbial data on cores indicate that Fe(III) oxyhydroxide coatings on sediment grains in local, organic carbon- and SO4/2- -rich zones have localized SO4/2- -reducing zones in which the formation of iron disulfides been depleted by microbial reduction and resulted in decreases dissolved iron concentrations. These localized zones of SO4/2- reduction, which are important for assessing zones of low dissolved iron for water-supply development, could be overlooked by aquifer studies that rely only on groundwater data from well-water samples for geochemical modeling. (C) 2000 Elsevier Science B.V.Fe(III) reduction in the Magothy aquifer of Long Island, NY, results in high dissolved-iron concentrations that degrade water quality. Geochemical modeling was used to constrain iron

  18. Morphology and internal structure of polymeric and carbon nanofibers

    Science.gov (United States)

    Zhong, Zhenxin

    Evaporation and the associated solidification are important factors that affect the diameter of electrospun nanofibers. The evaporation and solidification of a charged jet were controlled by varying the partial pressure of water vapor during electrospinning of poly(ethylene oxide) from aqueous solution. As the partial pressure of water vapor increases, the solidification process of the charged jet becomes slower, allowing elongation of the charged jet to continue longer and thereby to form thinner fibers. The morphology and internal structure of electrospun poly(vinylidene fluorides) nanofibers were investigated. Low voltage high resolution scanning electron microscopy was used to study the surface of electrospun nanofibers. Control of electrospinning process produced fibers with various morphological forms. Fibers that were beaded, branched, or split were obtained when different instabilities dominated in the electrospinning process. The high ratio of stretching during electrospinning aligns the polymer molecules along the fiber axis. A rapid evaporation of solvent during electrospinning gives fibers with small and imperfect crystallites. These can be perfected by thermal annealing. Fibers annealed at elevated temperature form plate-like lamellar crystals tightly linked by tie molecules. Electrospinning can provide ultrafine nanofibers with cross-sections that contain only a few polymer molecules. Ultrafine polymer nanofibers are extremely stable in transmission electron microscope. Electrospun nanofibers suspended on a holey carbon film showed features of individual polymer molecules. Carbon fibers with diameters ranging from 100 nm to several microns were produced from mesophase pitch by a low cost gas jet process. The structure of mesophase pitch-based carbon fibers was investigated as a function of heat treatment temperatures. Submicron-sized graphene oxide flakes were prepared by a combination of oxidative treatment and ultrasonic radiation. Because pitch is

  19. Internal corrosion of carbon steel piping in hot aquifers service

    Directory of Open Access Journals (Sweden)

    Simičić Miloš V.

    2011-01-01

    Full Text Available Internal corrosion of carbon steel pipelines is a major problem encountered in water service. In terms of prediction of the remaining lifetime for water pipelines based on the corrosion allowance, the three main approaches are corrosion modelling, corrosion inhibitor availability, and corrosion monitoring. In this study we used two theoretical corrosion models, CASSANDRA and NORSOK M-506 of quite different origin in order to predict uniform corrosivity of hot aquifers in eight different pipelines. Because of the varying calculation criteria for the different models, these can give very different corrosion rate predictions for the same data input. This is especially true under conditions where the formation of protective films may occur, such as at elevated temperatures. The evaluation of models was conducted by comparison using weight-loss coupons and three corrosion inhibitors were obtained from commercial suppliers. The tests were performed during the 60-day period. Even though inhibitors’ efficiencies of 98% had been achieved in laboratory testing, inhibitors’ availabilities of 85% have been used due to logistics problems and other issues. The results, given in mmpy, i.e. millimeter per year, are very consistent with NORSOK M-506 prediction. This is presumably because the model considers the effect of the formation of a passive iron carbonate film at temperatures above 80 °C and significant reduction in corrosion rate. Corrosion inhibitor A showed a better performance than inhibitors B and C in all cases but the target corrosion rates of less than 0.1 mmpy were achieved for all inhibitors. The chemical type of corrosion inhibitor A is based on quaternary amines mixed with methanol, isopropyl alcohol, xylene and ethylbenzene. Based on the obtained results the carbon steel lifetime of 30 years, provided proper inhibitors are present and 3mm corrosion allowance, can be achieved for hot aquifers service with presented water compositions.

  20. Polyurethane-derived N-doped porous carbon with interconnected sheet-like structure as polysulfide reservoir for lithium-sulfur batteries

    Science.gov (United States)

    Xiao, Suo; Liu, Songhang; Zhang, Jianqiu; Wang, Yong

    2015-10-01

    Environmental pollution and energy deficiency are two key issues for the sustainable development of the modern society. Polyurethane foam is a typical commercial polymer with a large production quantity and its waste needs to be recycled. Lithium-sulfur battery is a promising energy-storage device with high energy density and low cost, but its demerits such as poor conductivity of the sulfur and severe capacity degradation due to the soluble lithium polysulfides are still a big challenge. This work reports a facile method to prepare nitrogen-doped porous carbon (NPC) from the polyurethane foam (PUF) waste and use it as a reservoir to impregnate sulfur for lithium-sulfur batteries. The obtained NPC has a unique interconnected sheet-like porous morphology with a large surface area of 1315 m2 g-1. The NPC-S composite delivers a large reversible capacity of 1118 mAh g-1 with good cycling performances and excellent high-rate capabilities. A large reversible capacity of 460 mAh g-1 can be retained at a large current of 5C (8.35 A g-1) after 100 cycles.

  1. An experimental investigation of multiple sulfur isotope fractionations during heterogenous reactions between SO2 and activated carbon

    Science.gov (United States)

    Hamasaki, H.; Watanabe, Y.; Ohmoto, H.

    2010-12-01

    . We have recognized that the δ34S of SO2 in the system continuously decreased during the experiments from -0.6 to -1.4‰ (relative to the initial value) at 200 °C, and from -1.0 to -1.2 ‰ at 250 °C. The Δ33S of SO2 continued to decrease from 0 to -0.18 ‰ at 200 °C and 0.03 to -0.05 ‰ at 250 °C. Mass balance calculations suggest that the bulk S in activated carbon increased its δ34S value from 1.4 to 12.1 ‰ at 200 °C and 3.2 to 16.7 ‰ at 250 °C; and increased the Δ33S value from 0 to 0.18 ‰ at 200 °C and from 0.07 to 0.32 ‰ at 250 °C. Results of the sequential S extraction from the solid run products (activated C) indicate the total S content of 0.9 wt%, mostly in the forms of Cr-reductive S compounds (e.g., sulfites and polysulfides) and non Cr-reductive S compounds (e.g., organic sulfur, elemental sulfur, and sulfates). Our experimental results indicate that the adsorption of SO2, the reduction of S4+ to S0 (and/or Sx2-), and the oxidation of C0 to C4+ continued to occur during the reaction between SO2 and activated carbon at 200 °C and 250 °C, and that the redox reactions produced larger sulfur isotope effects (both in δ34S and Δ33S) compared to a simple adsorption process under our experimental conditions.

  2. Remarkably enhanced photocatalytic activity by sulfur-doped titanium dioxide in nanohybrids with carbon nanotubes

    Science.gov (United States)

    Khang, Nguyen Cao; Van, Duong Quoc; Thuy, Nguyen Minh; Minh, Nguyen Van; Minh, Phan Ngoc

    2016-12-01

    TiO2 doped S nanohybrids with carbon nanotubes (CNTs) were synthesized with CNTs, thiourea and TiO2 nanoparticles. The result indicated that the TiO2 nanoparticles with about 8 nm in size are attached on the sidewall of CNTs. The nanohybrids material can absorb at longer wavelength and the absorption even covers the whole range of visible region than that only TiO2 nanoparticles. Application of the catalysts to photocatalytic degradation of methylene blue (MB) was tested under visible light irradiation. The result suggests that a high MB degradation activity of S-TiO2/CNTs due to a reduce band gap of TiO2 when S is doped, and the decrease in the possibility of electron-hole recombination by CNTs. In addition, the density functional-theory (DFT) calculations of the electronic band structures and density of states (DOS) to understand the bonding states between TiO2 and CNTs, proved that the TiO2/CNTs system is stable.

  3. Sulfur and carbon isotopic variations in Neoproterozoic sedimentary rocks from southern China

    Institute of Scientific and Technical Information of China (English)

    CHU Xuelei; ZHANG Qirui; ZHANG Tonggang; FENG Lianjun

    2003-01-01

    A new set of δ34Ssulfide, δ34Ssulfate and δ13Ccarbonate values has been reported from Neoproterozoic sedimentary rocks in southern China. The interglacial black shales of the Datangpo Fm. display higher δ34Ssulfide values with >+20‰ average, but the postglacial black shales from the Doushantuo Fm. show negative δ34Ssulfide values. However, the Jinjiadong Fm., the same post-glaciation as the Doushantuo Fm., has positive δ34Ssulfide values, implying that the δ34S value of sedimentary sulfides would be controlled by lithofacies and paleogeographic environments. The δ34Ssulfate values relative to δ13Ccarbonate were obtained by extraction of trace sulfate from the successive carbonate sequences in the Yangtze Gorges sections. A preliminary interpretation suggests that the oceanic environment may fluctuate dramatically at the post-glacial Doushantuo stage and, then, recover its stability at the Dengying stage on the basis of the high resolution δ34S and δ13C curves of seawater.

  4. Kinetics and mechanism of heterogeneous oxidation of sulfur dioxide by ozone on surface of calcium carbonate

    Directory of Open Access Journals (Sweden)

    L. Li

    2006-01-01

    Full Text Available Sulfate particles play a key role in the air quality and the global climate, but the heterogeneous formation mechanism of sulfates on surfaces of atmospheric particles is not well established. Carbonates, which act as a reactive component in mineral dust due to their special chemical properties, may contribute significantly to the sulfate formation by heterogeneous processes. This paper presents a study on the oxidation of SO2 by O3 on CaCO3 particles. Using Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS, the formation of sulfite and sulfate on the surface was identified, and the roles of O3 and water in oxidation processes were determined. The results showed that in the presence of O3, SO2can be oxidized to sulfate on the surface of CaCO3 particles. The reaction is first order in SO2 and zero order in O3. The reactive uptake coefficient for SO2 [(0.6–9.8×1014 molecule cm-3] oxidation by O3 [(1.2–12×1014 molecule cm-3] was determined to be (1.4±0.3×10-7 using the BET area as the reactive area and (7.7±1.6×10-4 using the geometric area. A two-stage mechanism that involves adsorption of SO2 followed by O3 oxidation is proposed and the adsorption of SO2 on the CaCO3 surface is the rate-determining step. The proposed mechanism can well explain the experiment results. The atmospheric implications were explored based on a box model calculation. It was found that the heterogeneous reaction might be an important pathway for sulfate formation in the atmosphere.

  5. High Purity Hydrogen Production with In-Situ Carbon Dioxide and Sulfur Capture in a Single Stage Reactor

    Energy Technology Data Exchange (ETDEWEB)

    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.

  6. Mineralization, geochemistry, fluid inclusion and sulfur stable isotope studies in the carbonate hosted Baqoroq Cu-Zn-As deposit (NE Anarak

    Directory of Open Access Journals (Sweden)

    Mohammad Ali Jazi

    2015-10-01

    Full Text Available Introduction The Baqoroq Cu-Zn-As deposit is located northeast of the town ofAnarak in Isfahan province, in theeast central areaof Iran. Copper mineralization occursin upper cretaceous carbonate rocks.Studyof thegeologyof the Nakhlak area, the location ofa carbonate-hosted base metaldeposit, indicatesthe importance of stratigraphic, lithological and structural controls in the placement of this ore deposit. (Jazi et al., 2015.Some of the most world’s most important epigenetic, stratabound and discordant copperdeposits are the carbonate hosted Tsumeb and Kipushi type deposits,located in Africa. The Baqoroq deposit is believed to be of this type. Materials and methods In the current study, fifty rock samples were collected from old tunnels and surface mineralization. Twenty-two thin sections, ten polished sections and four thin-polished sections were prepared for microscopic study. Ten samples were selected for elemental analysis by ICP-OES (Inductively coupled plasma optical emission spectrometry by the Zar Azma Company (Tehran and AAS (Atomic absorption spectrometry at the Ferdowsi University of Mashhad. Seven doubly polished sections of barite mineralization were prepared for microthermometric analysis. Homogenization and last ice-melting temperatures were measured using a Linkam THMSG 600 combined heating and freezing stage at Ferdowsi University of Mashhad. Sulfur isotopes of five barite samples were determined by the Iso-Analytical Ltd. Company of the UK. The isotopic ratios are presented in per mil (‰notation relative to the Canyon Diablo Troilite. Results The upper Cretaceoushost rocks of the Baqoroq deposit include limestone, sandstone, and conglomerate units. Mineralization is controlled by two main factors: lithostratigraphy and structure. Epigenetic Cu-Zn mineralizationoccurs in ore zones as stratabound barite and barite-calcite veins and minor disseminated mineralization. Open space filling occurred as breccia matrix

  7. Preparation of sulfur-loaded activated carbons for removing gaseous elemental mercury%高温载硫活性炭的制备及脱汞能力研究

    Institute of Scientific and Technical Information of China (English)

    颜甜; 左宋林; 赵昕; 张宏阳; 施荫锐; 荀永葆

    2012-01-01

    研究了载硫温度、硫炭比(简称S/C),吸附温度等因素对载硫活性炭的硫含量、脱汞能力以及硫损失的影响,探讨载硫活性炭制备的工艺条件优化.结果表明,不同载硫温度下制备的载硫活性炭的气态Hg0吸附能力远强于原料活性炭;载硫温度不同时,负载到活性炭孔隙或表面上的硫的形态不同,导致了脱汞能力的差异,较合适的载硫温度为350℃:S/C为5%(质量分数,下同)时,随着吸附温度的升高,载硫活性炭的气态Hgo吸附量降低;在一定的载硫温度下,原料中S/C越高时,制备的载硫活性炭的硫含量越高、气态Hgo吸附能力越强,但其硫损失率也越高,从实际的使用效果来看,较合适的S/C为10%.%Series of sulfur-loaded activated carbons were prepared for removing gaseous elemental mercury from simulated flue gas. The effects of sulfur loading temperature, sulfur and carbon ratio (S/C), and adsorption temperature on the sulfur-loaded activated carbons were investigated from 3 aspects of sulfur loading quantity, mercury adsorption capacity and sulfur stability. Results showed that the mercury removal ability of sulfur loaded activated carbon was much higher than raw activated carbon) the form of sulfur that loading on the surface or pore of activated carbon was different under different loading temperature, the best temperature for sulfur loading was 350 V. When the S/C was 5% (mass ratio), mercury capture ability of the activated carbons was decreased with increasing the adsorption temperature. Under the same loading temperature, higher sulfur loading content would promote mercury capture ability but also increase the sulfur loss, and the optimal S/C was 10%.

  8. Combined effect of carbon dioxide and sulfur on vapor-liquid partitioning of metals in hydrothermal systems

    Science.gov (United States)

    Kokh, Maria A.; Lopez, Mathieu; Gisquet, Pascal; Lanzanova, Aurélie; Candaudap, Frédéric; Besson, Philippe; Pokrovski, Gleb S.

    2016-08-01

    Although CO2 is a ubiquitous volatile in geological fluids typically ranging from a few to more than 50 wt%, its effect on metal vapor-liquid fractionation during fluid boiling and immiscibility phenomena in the Earth's crust remains virtually unknown. Here we conducted first experiments to quantify the influence of CO2 on the partition of different metals in model water + salt + sulfur + CO2 systems at 350 °C and CO2 pressures up to 100 bar, which are typical conditions of formation of many hydrothermal ore deposits. In addition, we performed in situ Raman spectroscopy measurements on these two-phase systems, to determine sulfur and carbon speciation in the liquid and vapor phases. Results show that, in S-free systems and across a CO2 concentration range of 0-50 wt% in the vapor phase, the absolute vapor-liquid partitioning coefficients of metals (Kvap/liq = Cvap/Cliq, where C is the mass concentration of the metal in the corresponding vapor and liquid phase) are in the range 10-6-10-5 for Mo; 10-4-10-3 for Na, K, Cu, Fe, Zn, Au; 10-3-10-2 for Si; and 10-4-10-1 for Pt. With increasing CO2 from 0 to 50 wt%, Kvap/liq values decrease for Fe, Cu and Si by less than one order of magnitude, remain constant within errors (±0.2 log unit) for Na, K and Zn, and increase by 0.5 and 2 orders of magnitude, respectively for Au and Pt. The negative effect of CO2 on the partitioning of some metals is due to weakening of hydration of chloride complexes of some metals (Cu, Fe) in the vapor phase and/or salting-in effects in the liquid phase (Si), whereas both phenomena are negligible for complexes of other metals (Na, K, Zn, Mo). The only exception is Pt (and in a lesser extent Au), which partitions significantly more to the vapor of S-free systems in the presence of CO2, likely due to formation of volatile carbonyl (CO) complexes. In the S-bearing system, with H2S content of 0.1-1.0 wt% in the vapor, Kvap/liq values of Cu, Fe, Mo, and Au are in the range 0.01-0.1, those of Pt 0

  9. Phosphorus/sulfur Co-doped porous carbon with enhanced specific capacitance for supercapacitor and improved catalytic activity for oxygen reduction reaction

    Science.gov (United States)

    Zhou, Yao; Ma, Ruguang; Candelaria, Stephanie L.; Wang, Jiacheng; Liu, Qian; Uchaker, Evan; Li, Pengxi; Chen, Yongfang; Cao, Guozhong

    2016-05-01

    Phosphorus (P)/sulfur (S) co-doped porous carbon derived from resorcinol and furaldehyde are synthesized through one-step sol-gel processing with the addition of phosphorus pentasulfide as P and S source followed with freeze-drying and pyrolysis in nitrogen. The P/S co-doping strategy facilitates the pore size widening both in micropore and mesopore regions, together with the positive effect on the degree of graphitization of porous carbon through elimination of amorphous carbon through the formation and evaporation of carbon disulfide. As an electrode for supercapacitor application, P/S co-doped porous carbon demonstrates 43.5% improvement on specific capacitance of the single electrode compared to pristine porous carbon in organic electrolyte at a current of 0.5 mA due to the P-induced pseudocapacitive reactions. As for electrocatalytic use, promoted electrocatalytic activity and high resistance to crossover effects of oxygen reduction reaction (ORR) in alkaline media are observed after the introduction of P and S into porous carbon. After air activation, the specific capacitance of the single electrode of sample PS-pC reaches up to 103.5 F g-1 and an improved oxygen reduction current density.

  10. Conversion from Li2SO4 to Li2S@C on carbon paper matrix: A novel integrated cathode for lithium-sulfur batteries

    Science.gov (United States)

    Wang, D. H.; Xie, D.; Yang, T.; Zhong, Y.; Wang, X. L.; Xia, X. H.; Gu, C. D.; Tu, J. P.

    2016-11-01

    Integral construction of lithium sulfide (Li2S) cathode is indispensable and vital for developing high-performance lithium-sulfur (Li-S) batteries. Herein we have demonstrated a facile strategy for fabricating free-standing carbon paper supported Li2S@C (P-Li2S@C) integrated cathode. The P-Li2S@C cathode is synthesized through simple pyrolysis of low-cost lithium sulfate (Li2SO4) and chitosan, and embedded in the double carbon matrixes with carbon paper support and outer CVD-carbon layer. Li2S nanoparticles are homogeneously dispersed in the above designed double carbon matrixes. The P-Li2S@C cathode exhibits an initial discharge capacity of 820 mAh g-1 at 0.1 C and still maintains 430 mAh g-1after 100 cycles, superior to the P-Li2S counterpart (480 mAh g-1 at 0.1 C and 150 mAh g-1 after 100 cycles). Our research verifies the effectiveness of double carbon modification on the Li2S, especially, the outer carbon coating not only improves the electrical conductivity of electrode, but also further prohibits the "shuttle effect" of polysulfides.

  11. Accessibility, searchability, transparency and engagement of soil carbon data: The International Soil Carbon Network

    Science.gov (United States)

    Harden, Jennifer W.; Hugelius, Gustaf; Koven, Charlie; Sulman, Ben; O'Donnell, Jon; He, Yujie

    2016-04-01

    Soils are capacitors for carbon and water entering and exiting through land-atmosphere exchange. Capturing the spatiotemporal variations in soil C exchange through monitoring and modeling is difficult in part because data are reported unevenly across spatial, temporal, and management scales and in part because the unit of measure generally involves destructive harvest or non-recurrent measurements. In order to improve our fundamental basis for understanding soil C exchange, a multi-user, open source, searchable database and network of scientists has been formed. The International Soil Carbon Network (ISCN) is a self-chartered, member-based and member-owned network of scientists dedicated to soil carbon science. Attributes of the ISCN include 1) Targeted ISCN Action Groups which represent teams of motivated researchers that propose and pursue specific soil C research questions with the aim of synthesizing seminal articles regarding soil C fate. 2) Datasets to date contributed by institutions and individuals to a comprehensive, searchable open-access database that currently includes over 70,000 geolocated profiles for which soil C and other soil properties. 3) Derivative products resulting from the database, including depth attenuation attributes for C concentration and storage; C storage maps; and model-based assessments of emission/sequestration for future climate scenarios. Several examples illustrate the power of such a database and its engagement with the science community. First, a simplified, data-constrained global ecosystem model estimated a global sensitivity of permafrost soil carbon to climate change (g sensitivity) of -14 to -19 Pg C °C-1 of warming on a 100 years time scale. Second, using mathematical characterizations of depth profiles for organic carbon storage, C at the soil surface reflects Net Primary Production (NPP) and its allotment as moss or litter, while e-folding depths are correlated to rooting depth. Third, storage of deep C is highly

  12. Influence of carbon sources on nutrient removal in A(2)/O-MBRs: Availability assessment of internal carbon source.

    Science.gov (United States)

    Xu, Rongle; Fan, Yaobo; Wei, Yuansong; Wang, Yawei; Luo, Nan; Yang, Min; Yuan, Xing; Yu, Rong

    2016-10-01

    Both internal carbon source and some external carbon sources were used to improve the nutrient removal in Anaerobic-Anoxic-Oxic-Membrane Bioreactor (A(2)/O-MBRs), and their technical and cost analysis was investigated. The experimental results showed that the nutrient removals were improved by all the carbon source additions. The total nitrogen and phosphorus removal efficiency were higher in the experiments with external carbon source additions than that with internal carbon source addition. It was found that pathways of nitrogen and phosphorus transform were different dependent on different carbon source additions by the mass balance analysis. With external carbon source addition, the simultaneous nitrification and denitrification occurred in aerobic zone, and the P-uptake in aerobic phase was evident. Therefore, with addition of C-MHP (internal carbon source produced from sludge pretreatment by microwave-H2O2 process), the denitrification and phosphorus-uptake in anoxic zone was notable. Cost analysis showed that the unit nitrogen removal costs were 57.13CNY/kg N of C-acetate addition and 54.48CNY/kgN of C-MHP addition, respectively. The results indicated that the C-MHP has a good technical and economic feasibility to substitute external carbon sources partially for nutrient removal.

  13. Synergistically Enhanced Polysulfide Chemisorption Using a Flexible Hybrid Separator with N and S Dual-Doped Mesoporous Carbon Coating for Advanced Lithium-Sulfur Batteries.

    Science.gov (United States)

    Balach, Juan; Singh, Harish K; Gomoll, Selina; Jaumann, Tony; Klose, Markus; Oswald, Steffen; Richter, Manuel; Eckert, Jürgen; Giebeler, Lars

    2016-06-15

    Because of the outstanding high theoretical specific energy density of 2600 Wh kg(-1), the lithium-sulfur (Li-S) battery is regarded as a promising candidate for post lithium-ion battery systems eligible to meet the forthcoming market requirements. However, its commercialization on large scale is thwarted by fast capacity fading caused by the Achilles' heel of Li-S systems: the polysulfide shuttle. Here, we merge the physical features of carbon-coated separators and the unique chemical properties of N and S codoped mesoporous carbon to create a functional hybrid separator with superior polysulfide affinity and electrochemical benefits. DFT calculations revealed that carbon materials with N and S codoping possess a strong binding energy to high-order polysulfide species, which is essential to keep the active material in the cathode side. As a result of the synergistic effect of N, S dual-doping, an advanced Li-S cell with high specific capacity and ultralow capacity degradation of 0.041% per cycle is achieved. Pushing our simple-designed and scalable cathode to a highly increased sulfur loading of 5.4 mg cm(-2), the Li-S cell with the functional hybrid separator can deliver a remarkable areal capacity of 5.9 mAh cm(-2), which is highly favorable for practical applications.

  14. Authigenic minerals related to carbon and sulfur biogeochemical cycling from deep-sea active methane seeps offshore South-West Africa

    Science.gov (United States)

    Pierre, C.; Blanc-Valleron, M.; Demange, J.; Boudouma, O.; Pape, T.; Himmler, T.; Fekete, N.; Spiess, V.

    2011-12-01

    The South-West African continental margin is well known for occurrences of active methane-rich fluid seeps that are associated with seafloor pockmarks in a broad range of water depths, from the shelf to the deep basins. High gas flares in the water column, luxurious oases of benthic fauna, gas hydrate accumulations and diagenetic carbonate crusts have been observed at these seeps. During the M76/3a expedition of R/V METEOR (summer 2008) gravity cores recovered abundant authigenic carbonate concretions from five pockmarks of the South-West African margin including previously studied sites (Hydrate Hole, Worm Hole, Regab Pockmark) and two sites (Deep Hole, Baboon Cluster) newly discovered during the cruise. Carbonate concretions were mostly associated to sediments settled by seep-associated benthic macrofauna and bearing shallow gas hydrates. We present new results of the comprehensive analysis of the mineralogy and isotope geochemistry of the diagenetic carbonates sampled in the five pockmarks. The mineralogy of authigenic carbonates is dominated by magnesian calcite and aragonite, associated occasionally with dolomite. The oxygen and carbon isotopic compositions of authigenic carbonates (+2.4 < δ18O % V-PDB < +6.2 ; -61.0 < δ13C % V-PDB < -40.1) indicate that microbial anaerobic oxidation of methane (AOM) was the main process controling carbonate precipitation within sub-seafloor sediments deposited from the glacial-time up to the present. The frequent occurrence of diagenetic gypsum crystals within the sediments demonstrates that bio-irrigation with oxygenated bottom water by the burrowing activity of benthic fauna caused the secondary oxidation of reduced sulfur (hydrogen sulfide and pyrite) that was produced by sulfate reducting bacteria as a by-product of AOM; during the sulfide oxidation process, the released acidity induced the partial dissolution of carbonates. Our results demonstrate also the strong link that existed between the carbon and sulfur cycles

  15. Genome sequencing of Sulfolobus sp. A20 from Costa Rica and comparative analyses of the putative pathways of carbon, nitrogen and sulfur metabolism in various Sulfolobus strains

    Directory of Open Access Journals (Sweden)

    Xin Dai

    2016-11-01

    Full Text Available The genome of Sulfolobus sp. A20 isolated from a hot spring in Costa Rica was sequenced. This circular genome of the strain is 2,688,317 bp in size and 34.8% in G+C content, and contains 2,591 open reading frames (ORFs. Strain A20 shares ~95.6% identity at the 16S rRNA gene sequence level and less than 30% DNA-DNA hybridization (DDH values with the most closely related known Sulfolobus species (i.e., S. islandicus and S. solfataricus, suggesting that it represents a novel Sulfolobus species. Comparison of the genome of strain A20 with those of the type strains of S. solfataricus, S. acidocaldarius, S. islandicus and S. tokodaii, which were isolated from geographically separated areas, identified 1,801 genes conserved among all Sulfolobus species analyzed (core genes. Comparative genome analyses show that central carbon metabolism in Sulfolobus is highly conserved, and enzymes involved in the Entner-Doudoroff pathway, the tricarboxylic acid cycle and the CO2 fixation pathways are predominantly encoded by the core genes. All Sulfolobus species encode genes required for the conversion of ammonium into glutamate/glutamine. Some Sulfolobus strains have gained the ability to utilize additional nitrogen source such as nitrate (i.e. S. islandicus strain REY15A, LAL14/1, M14.25 and M16.27 or urea (i.e. S. islandicus HEV10/4, S. tokodaii strain7 and S. metallicus DSM 6482. The strategies for sulfur metabolism are most diverse and least understood. S. tokodaii encodes sulfur oxygenase/reductase (SOR, whereas both S. islandicus and S. solfataricus contain genes for sulfur reductase (SRE. However, neither SOR nor SRE genes exist in the genome of strain A20, raising the possibility that an unknown pathway for the utilization of elemental sulfur may be present in the strain. The ability of Sulfolobus to utilize nitrate or sulfur is encoded by a gene cluster flanked by IS elements or their remnants. These clusters appear to have become fixed at a specific

  16. Genome Sequencing of Sulfolobus sp. A20 from Costa Rica and Comparative Analyses of the Putative Pathways of Carbon, Nitrogen, and Sulfur Metabolism in Various Sulfolobus Strains.

    Science.gov (United States)

    Dai, Xin; Wang, Haina; Zhang, Zhenfeng; Li, Kuan; Zhang, Xiaoling; Mora-López, Marielos; Jiang, Chengying; Liu, Chang; Wang, Li; Zhu, Yaxin; Hernández-Ascencio, Walter; Dong, Zhiyang; Huang, Li

    2016-01-01

    The genome of Sulfolobus sp. A20 isolated from a hot spring in Costa Rica was sequenced. This circular genome of the strain is 2,688,317 bp in size and 34.8% in G+C content, and contains 2591 open reading frames (ORFs). Strain A20 shares ~95.6% identity at the 16S rRNA gene sequence level and Sulfolobus species (i.e., Sulfolobus islandicus and Sulfolobus solfataricus), suggesting that it represents a novel Sulfolobus species. Comparison of the genome of strain A20 with those of the type strains of S. solfataricus, Sulfolobus acidocaldarius, S. islandicus, and Sulfolobus tokodaii, which were isolated from geographically separated areas, identified 1801 genes conserved among all Sulfolobus species analyzed (core genes). Comparative genome analyses show that central carbon metabolism in Sulfolobus is highly conserved, and enzymes involved in the Entner-Doudoroff pathway, the tricarboxylic acid cycle and the CO2 fixation pathways are predominantly encoded by the core genes. All Sulfolobus species encode genes required for the conversion of ammonium into glutamate/glutamine. Some Sulfolobus strains have gained the ability to utilize additional nitrogen source such as nitrate (i.e., S. islandicus strain REY15A, LAL14/1, M14.25, and M16.27) or urea (i.e., S. islandicus HEV10/4, S. tokodaii strain7, and S. metallicus DSM 6482). The strategies for sulfur metabolism are most diverse and least understood. S. tokodaii encodes sulfur oxygenase/reductase (SOR), whereas both S. islandicus and S. solfataricus contain genes for sulfur reductase (SRE). However, neither SOR nor SRE genes exist in the genome of strain A20, raising the possibility that an unknown pathway for the utilization of elemental sulfur may be present in the strain. The ability of Sulfolobus to utilize nitrate or sulfur is encoded by a gene cluster flanked by IS elements or their remnants. These clusters appear to have become fixed at a specific genomic site in some strains and lost in other strains during the

  17. Wet Chemistry Synthesis of Multidimensional Nanocarbon-Sulfur Hybrid Materials with Ultrahigh Sulfur Loading for Lithium-Sulfur Batteries.

    Science.gov (United States)

    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.

  18. Potential biodiversity benefits from international programs to reduce carbon emissions from deforestation.

    Science.gov (United States)

    Siikamäki, Juha; Newbold, Stephen C

    2012-01-01

    Deforestation is the second largest anthropogenic source of carbon dioxide emissions and options for its reduction are integral to climate policy. In addition to providing potentially low cost and near-term options for reducing global carbon emissions, reducing deforestation also could support biodiversity conservation. However, current understanding of the potential benefits to biodiversity from forest carbon offset programs is limited. We compile spatial data on global forest carbon, biodiversity, deforestation rates, and the opportunity cost of land to examine biodiversity conservation benefits from an international program to reduce carbon emissions from deforestation. Our results indicate limited geographic overlap between the least-cost areas for retaining forest carbon and protecting biodiversity. Therefore, carbon-focused policies will likely generate substantially lower benefits to biodiversity than a more biodiversity-focused policy could achieve. These results highlight the need to systematically consider co-benefits, such as biodiversity in the design and implementation of forest conservation programs to support international climate policy.

  19. International Oil Price’s Impacts on Carbon Emission in China’s Transportation Industry

    Directory of Open Access Journals (Sweden)

    Guoxing Zhang

    2014-09-01

    Full Text Available Purpose: This paper analyses the impact mechanism of international oil price on the industrial carbon emission, and uses the partial least squares regression model to study international oil price’s impact on carbon emissions in China’s transportation industry.Design/methodology/approach: This paper chooses five independent variables of GDP, international oil price, private car population, passenger and freight transportation volume as impact factors to investigate industrial carbon emissions, the paper also analyses the impact mechanism of international oil price on the industrial carbon emission, and finally the paper uses the partial least squares regression model to study international oil price’s impact on carbon emissions in China’s transportation industry. With the independent variables’ historical data from 1994 to 2009 as a sample, the fitting of the industry carbon emissions is satisfying. And based on the data of 2011, the paper maintains the private car owning, passenger and freight transportation volume to study international oil prices’ impact on the industry carbon emissions at different levels of GDP.Findings: The results show that: with the same GDP growth, the industry carbon emissions increase with the rise in international oil prices, and vice versa, the industry carbon emissions decrease; and lastly when GDP increases to a certain extent, in both cases of international oil prices’ rise or fall, the industry carbon emissions will go up, and the industry carbon emissions increase even faster while the energy prices are rising.Practical implications: Limit the growth in private-vehicle ownership, change China's transport sector within the next short-term in the structure of energy consumption and put forward China's new energy, alternative energy sources and renewable energy application so as to weaken the dependence on international oil, and indirectly slowdown China's GDP growth rate, which are all possible

  20. Sulfur Dioxide and the Production of Sulfuric Acid on Present-Day and Early Mars: Implications for the Lack of Detected Carbonates on the Surface

    Science.gov (United States)

    Levine, Joel S.; Summers, Michael E.

    2008-01-01

    In the early history of Mars, volcanic activity associated with the formation of the Tharsis ridge produced a very large amount of atmospheric SO2--on the order of a bar of atmospheric SO2. In the present-day atmosphere of Mars, the lifetime of SO2 is relatively short with a lifetime of less than a day. The short lifetime of SO2 in the present Mars atmosphere makes the production of significant levels of H2SO4 very difficult since the SO2 may be destroyed by various chemical and photochemical processes before the SO2 can be converted to H2SO4. However, photochemical calculations performed and described here, indicate that enhanced atmospheric levels of CO2 in the early atmosphere of Mars resulted in a significantly enhanced atmospheric lifetime for SO2 up to several years. With a significantly enhanced atmospheric lifetime, SO2 could readily form large amounts of H2SO4, which precipitated out of the atmosphere in the form of droplets. The precipitated H2SO4 then reacted with potential surface carbonates, destroying the carbonates and resulting in the abundant and widespread distribution of sulfates on the surface of Mars as detected by recent Mars missions.

  1. Production of sulfur gases and carbon dioxide by synthetic weathering of crushed drill cores from the Santa Cruz porphyry copper deposit near Casa Grande, Pinal County, Arizona

    Science.gov (United States)

    Hinkle, M.E.; Ryder, J.L.; Sutley, S.J.; Botinelly, T.

    1990-01-01

    Samples of ground drill cores from the southern part of the Santa Cruz porphyry copper deposit, Casa Grande, Arizona, were oxidized in simulated weathering experiments. The samples were also separated into various mineral fractions and analyzed for contents of metals and sulfide minerals. The principal sulfide mineral present was pyrite. Gases produced in the weathering experiments were measured by gas chromatography. Carbon dioxide, oxygen, carbonyl sulfide, sulfur dioxide and carbon disulfide were found in the gases; no hydrogen sulfide, organic sulfides, or mercaptans were detected. Oxygen concentration was very important for production of the volatiles measured; in general, oxygen concentration was more important to gas production than were metallic element content, sulfide mineral content, or mineral fraction (oxide or sulfide) of the sample. The various volatile species also appeared to be interactive; some of the volatiles measured may have been formed through gas reactions. ?? 1990.

  2. The internal consistency of the North Sea carbonate system

    NARCIS (Netherlands)

    Salt, S.; Thomas, H.; Bozec, Y.; Borges, A.V.; de Baar, H.J.W

    2016-01-01

    In 2002 (February) and 2005 (August), the full suite of carbonate system parameters (total alkalinity (AT), dissolved inorganic carbon (DIC), pH, and partial pressure of CO2 (pCO2) were measured on two re-occupations of the entire North Sea basin, with three paramete

  3. Pudding-typed cobalt sulfides/nitrogen and sulfur dual-doped hollow carbon spheres as a highly efficient and stable oxygen reduction electrocatalyst

    Science.gov (United States)

    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.

  4. Route to sustainable lithium-sulfur batteries with high practical capacity through a fluorine free polysulfide catholyte and self-standing Carbon Nanofiber membranes.

    Science.gov (United States)

    Lim, Du-Hyun; Agostini, Marco; Nitze, Florian; Manuel, James; Ahn, Jou-Hyeon; Matic, Aleksandar

    2017-07-24

    We report on a new strategy to improve the capacity, reduce the manufacturing costs and increase the sustainability of Lithium-Sulfur (LiS) batteries. It is based on a semi-liquid cathode composed of a Li2S8 polysulphide catholyte and a binder-free carbon nanofiber membrane with tailored morphology. The polysulphides in the catholyte have the dual role of active material and providing Li(+)-conduction, i.e. no traditional Li-salt is used in this cell. The cell is able to deliver an areal capacity as high as 7 mAh cm(-2), twice than that of commercial Lithium-ion batteries (LiBs) and 2-4 times higher than that of state-of-the-art LiS cells. In addition, the battery concept has an improved sustainability from a material point of view by being mainly based on sulfur and carbon and being completely fluorine-free, no fluorinated salt or binders are used, and has potential for upscaling and competitive price. The combination of these properties makes the semi-liquid LiS cell here reported a very promising new concept for practical large-scale energy storage applications.

  5. Development of internal reforming carbonate fuel cell stack technology

    Energy Technology Data Exchange (ETDEWEB)

    Farooque, M.

    1990-10-01

    Activities under this contract focused on the development of a coal-fueled carbonate fuel cell system design and the stack technology consistent with the system design. The overall contract effort was divided into three phases. The first phase, completed in January 1988, provided carbonate fuel cell component scale-up from the 1ft{sup 2} size to the commercial 4ft{sup 2} size. The second phase of the program provided the coal-fueled carbonate fuel cell system (CGCFC) conceptual design and carried out initial research and development needs of the CGCFC system. The final phase of the program emphasized stack height scale-up and improvement of stack life. The results of the second and third phases are included in this report. Program activities under Phase 2 and 3 were designed to address several key development areas to prepare the carbonate fuel cell system, particularly the coal-fueled CFC power plant, for commercialization in late 1990's. The issues addressed include: Coal-Gas Related Considerations; Cell and Stack Technology Improvement; Carbonate Fuel Cell Stack Design Development; Stack Tests for Design Verification; Full-Size Stack Design; Test Facility Development; Carbonate Fuel Cell Stack Cost Assessment; and Coal-Fueled Carbonate Fuel Cell System Design. All the major program objectives in each of the topical areas were successfully achieved. This report is organized along the above-mentioned topical areas. Each topical area has been processed separately for inclusion on the data base.

  6. Carbon Fiber Manufacturing Facility Siting and Policy Considerations: International Comparison

    Energy Technology Data Exchange (ETDEWEB)

    Cook, Jeffrey J. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Booth, Samuel [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2017-06-21

    Carbon fiber is increasingly used in a wide variety of applications due largely to its superior material properties such as high strength-to-weight ratio. The current global carbon fiber manufacturing industry is predominately located in China, Europe, Japan, and the United States. The carbon fiber market is expected to expand significantly through 2024 and to require additional manufacturing capacity to meet demand. Carbon fiber manufacturing facilities can offer significant economic development and employment opportunities as exemplified by the $1 billion investment and 500 jobs expected at a new Toray plant in Moore, South Carolina. Though the market is expected to expand, it is unclear where new manufacturing facilities will locate to meet demand. This uncertainty stems from the lack of research evaluating how different nations with significant carbon fiber manufacturing capacity compare as it relates to certain manufacturing facility siting factors such as costs of labor and energy as well as policy directed at supporting carbon fiber development, domestic deployment, and exports. This report fills these gaps by evaluating the top carbon fiber manufacturing countries, including China, European Union countries, Japan, Mexico, South Korea, Taiwan, and the United States. The report documents how the United States compares to these countries based on a range of manufacturing siting considerations and existing policies related to carbon fiber. It concludes with a discussion of various policy options the United States could adopt to both (1) increase the competitiveness of the United States as it relates to attracting new carbon fiber manufacturing and (2) foster broader end-use markets for deployment.

  7. Adsorption of sulfur dioxide by active carbon treated by nitric acid: I. Effect of the treatment on adsorption of SO{sub 2} and extractability of the acid formed

    Energy Technology Data Exchange (ETDEWEB)

    Lisovskii, A.; Semiat, R.; Aharoni, C. [Technion-Israle Institute of Technology, Haifa (Israel). Chemical Engineering Dept.

    1997-12-31

    Activated carbon is used as an adsorbent in flue gas cleaning. The process of adsorptive-catalytic cleaning of gas from sulfur dioxide using active carbon, treated by concentrated nitric acid, was studied. After oxidative treatment the acidity of the carbon increases and the basicity decreases. This results in an increase of the SO{sub 2} adsorption and its oxidation to SO{sub 3}, and in weaker retention of the sulfuric acid formed. This facilitates the removal of H{sub 2}SO{sub 4} by washing of the carbon and allows to obtain a more concentrated acid. The efficiency of the treated carbon is also higher in the process of SO{sub 2} removal from a gas similar in composition to stack gases. 13 refs., 1 fig., 7 tabs.

  8. Replacement of hazardous chromium impregnating agent from silver/copper/chromium-impregnated active carbon using triethylenediamine to remove hydrogen sulfide, trichloromethane, ammonia, and sulfur dioxide.

    Science.gov (United States)

    Wu, Li-Chun; Chung, Ying-Chien

    2009-03-01

    Activated carbon (AC) is widely used as an effective adsorbent in many applications, including industrial-scale air purification systems and air filter systems in gas masks. In general, ACs without chemical impregnation are good adsorbents of organic vapors but poor adsorbents of low-molecular-weight or polar gases such as chlorine, sulfur dioxide (SO2), formaldehyde, and ammonia (NH3). Impregnated ACs modified with metallic impregnating agents (ASC-carbons; e.g., copper, chromium, and silver) enhance the adsorbing properties of the ACs for simultaneously removing specific poisonous gases, but disposal of the chromium metal salt used to impregnate the ACs has the potential to result in situations that are toxic to both humans and the environment, thereby necessitating the search for replaceable organic impregnating agents that represent a much lower risk. The aim of this study was to assess the gas removal efficiency of an AC in which the organic impregnating agent triethylenediamine (TEDA) largely replaced the metallic impregnating agent chromium. We assessed batch and continuous adsorption capacities in situ for removing simulated hydrogen sulfide (H2S), trichloromethane (CHCl3), NH3, and SO2 gases. Brunauer-Emmet-Teller measurements and scanning electron microscopy analyses identified the removal mechanism by which TEDA-impregnated AS-carbon (dechromium ASC-carbon) adsorbs gases and determined the removal capacity for H2S, CHCl3, NH3, and SO2 to be 311, 258, 272, and 223 mg/g-C, respectively. These results demonstrate that TEDA-impregnated AS-carbon is significantly more efficient than ASC-carbon in adsorbing these four gases. Organic TEDA-impregnating agents have also been proven to be a reliable and environmental friendly agent and therefore a safe replacement of the hazardous chromium found in conventional ASC-carbon used in removing toxic gases from the airstream.

  9. Coincident negative shifts in sulfur and carbon isotope compositions prior to the end-Permian mass extinction at Shangsi Section of Guangyuan, South China

    Institute of Scientific and Technical Information of China (English)

    Pengwei LI; Junhua HUANG; Min CHEN; Xiao BAI

    2009-01-01

    Sulfur isotope composition of carbonate-associated sulfate (δ3 434SCAS) and carbon isotope composition of carbonate (δ13Ccarb) were jointly investigated on the Late Permian rocks at Shangsi Section, Guanyuan, Northeast Sichuan, South China. Both δ3 4SCAS and δ13Ccarb show gradual decline trends in Late Permian strata, inferring the occurrence of the long-term variation of marine environmental conditions. Associated with the long-term variation are the two coincident negative shifts in δ3 4SCAS and δ13Ccarb, with one occurring at the boundary between Middle Permian Maokou Formation and Late Permian Wujiaping Formation and another at Middle Dalong Formation. Of significance is the second shift which clearly predates the regression and the biotic crisis at the end of Permian at Shangsi Section, providing evidence that a catastrophic event occurred prior to the biotic crisis. The frequent volcanisms indicated by the volcanic rocks or fragments, and the upwelling are proposed to cause the second negative excursion. An abrupt extreme negative δ3 4 SCAS (ca.-20‰) associated with a low relative concentration of CAS and total organic carbon without large change in δ13Ccarb is found at the end of the second shift, which might arise from the short-term oxygenation of bottom waters and sediments that resulted from the abrupt sea level drop.

  10. Carbon Budget for Basic Needs: Implications of International Equity and Sustainability%Carbon Budget for Basic Needs: Implications of International Equity and Sustainability

    Institute of Scientific and Technical Information of China (English)

    Pan Jiahua

    2011-01-01

    The fundamental way of satisfying the basic needs of human development is to secure the basic needs, limit luxurious and wasteful emissions, and ensure the fulfillment of climate targets, so as to achieve intra- and intergenerational equity. In this paper, the author discusses and analyzes a series of challenges that the development has to face, such as poverty elimination, urbanization, and industrialization, and the problems of increased consumption that is brought about by the improvement of living standards; the author distinguishes the stock emission, which does not need annual updating, and the flow emission of regular consumption; the author also defines the standards of energy consumption and carbon emissions that can meet the basic needs. On this basis, the author proposes the concept and method of carbon budget, compares this method with other means, and in particular, studies and analyzes the implications of international equity and sustainability of carbon budget as part of the international climate regime design.

  11. Effect of sulfuric acid on textural properties and catalytic performance of ruthenium-containing ordered mesoporous carbon prepared via a direct RuCl3/SBA-15 hard templated method.

    Science.gov (United States)

    Lan, Guojun; Tang, Haodong; Liu, Huazhang; Ni, Jun; Li, Ying

    2014-09-01

    Ruthenium-containing ordered mesoporous carbon (Ru-OMC) catalysts with highly dispersed Ru nanoparticles semi-embedded in carbon framework were prepared via a direct RuCl3/SBA-15 hard templated method. The effect of sulfuric acid on the texture structure and catalytic performance of Ru-OMC were studied. The status of Ru nanoparticles and mesoporous structure of Ru-OMC catalysts were characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), nitrogen sorption, scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM) and CO chemisorption techniques. The addition of appropriate amount of sulfuric acid is necessary to improve the ordered mesoporous structure of Ru-OMC catalysts. The framework of carbon structure shrinks with the increase in sulfur acid contents, which is proved by a slight decrease in surface area and increase in pore diameters for Ru-OMC with different sulfur contents. The turnover frequency (TOF) for Ru-OMC reaches the highest up to 3.98 s(-1) in benzene hydrogenation with optimized sulfur acid content of 0.08 mmol/g sucrose.

  12. Combination of cathodic reduction with adsorption for accelerated removal of Cr(VI) through reticulated vitreous carbon electrodes modified with sulfuric acid-glycine co-doped polyaniline.

    Science.gov (United States)

    Mo, Xi; Yang, Zhao-hui; Xu, Hai-yin; Zeng, Guang-ming; Huang, Jing; Yang, Xia; Song, Pei-pei; Wang, Li-ke

    2015-04-09

    Improving the reduction kinetics is crucial in the electroreduction process of Cr(VI). In this study, we developed a novel adsorption-electroreduction system for accelerated removal of Cr(VI) by employing reticulated vitreous carbon electrode modified with sulfuric acid-glycine co-doped polyaniline (RVC/PANI-SA-GLY). Firstly, response surface methodology confirmed the optimum polymerization condition of co-doped polyaniline for modifying electrodes (Aniline, sulfuric acid and glycine, respectively, of 0.2 mol/L, 0.85 mol/L, 0.93 mol/L) when untraditional dopant glycine was added. Subsequently, RVC/PANI-SA-GLY showed higher Cr(VI) removal percentages in electroreduction experiments over RVC electrode modified with sulfuric acid doped polyaniline (RVC/PANI-SA) and bare RVC electrode. In contrast to RVC/PANI-SA, the improvement by RVC/PANI-SA-GLY was more significant and especially obvious at more negative potential, lower initial Cr(VI) concentration, relatively less acidic solution and higher current densities, best achieving 7.84% higher removal efficiency with entire Cr(VI) eliminated after 900 s. Current efficiencies were likewise enhanced by RVC/PANI-SA-GLY under quite negative potentials. Fourier transform infrared (FTIR) and energy dispersive spectrometer (EDS) analysis revealed a possible adsorption-reduction mechanism of RVC/PANI-SA-GLY, which greatly contributed to the faster reduction kinetics and was probably relative to the absorption between protonated amine groups of glycine and HCrO4(-). Eventually, the stability of RVC/PANI-SA-GLY was proven relatively satisfactory. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Effects of temperature on internal friction of Graphit-iC graphite-like carbon coatings

    Science.gov (United States)

    Zhu, Zhi-yong; Shi, Wen; Wan, Zi; Yuan, Jun-feng; Li, Xiao

    2013-12-01

    Graphit-iC graphite-like carbon coatings were deposited on SDC90 cold work die steel by using an unbalanced magnetron sputtering technology. Effects of the temperature on microstructure and internal friction of the carbon coatings were characterized by Raman spectroscopy (Raman) and a low-frequency mechanical analyzer (LMA-1) testing system. The results indicate that the internal friction of the two-side deposited carbon coatings is small (2.17×10-4), being higher than one of the substrate (1.63×10-4), and increases with temperature. However, there is an internal friction peak at 250°C accompanied with partial sp3 transferred to sp2 and increasing the intensity ratio ID/IG. There is gradual graphitization tendency of the carbon coatings as temperatures increase from 25°C to 350 °C. This would be progressive transformation from amorphous to crystalline.

  14. Investigation of the interaction of carbon dioxide fluid with internal and external single-wall carbon nanotubes by DFT

    Directory of Open Access Journals (Sweden)

    M. Oftadeh

    2011-07-01

    Full Text Available The effective parameters of (5, 0 and (5, 5 single-wall carbon nanotubes during the interaction with carbon dioxide as sensors are determined. The interaction of carbon dioxide  molecules with internal and external walls of the nanotubes is studied using Gaussian 03 coding by density functional theory (DFT at the B3LYP/6-311G level of theory. CO2 rotation around tube axles vertically and parallel to the internal and external walls has been investigated. The carbon dioxide molecule is predicted to bind only weakly to nanotubes, and the tube-molecule interactions can be identified as physisorption. CO2 adsorption is stronger on external wallsthan on internal walls, and adsorption on the external wall of (5, 0 is stronger than on the external wall of (5, 5; the adsorption energies are exothermic and equal to -0.8884 and -0.0528 kcal/mol, respectively. The rotation energy barrier for (5, 5 is lower than that for (5, 0 in all rotations, therefore in these interactions (5, 5 is more active. The energy gap significantly changes in the presence of  carbon  dioxide molecules on the inside surface of (5, 0 and the electric conductivity is affected, but no remarkable change is observed in the electronic structure of (5, 5.

  15. International Assessment of Carbon Nanotube Manufacturing and Applications

    Science.gov (United States)

    2007-06-01

    on its mass-produced, CVD-grown MWCNTs in PET ( polyethylene terephthalate ), PET fibers, and PEEK (polyetheretherketone) polymers loaded with 0.1-1.6...membrane fuel cell PET Polyethylene terephthalate PLV Pulsed laser vaporization PP Polypropylene, a plastic polymer Pt Platinum PVP...electron microscope (SEM) image of cross section of 5% MWCNTs in polycarbonate matrix, Nano Carbon Technologies Co, Ltd, Japan

  16. Lunar sulfur

    Science.gov (United States)

    Kuck, David L.

    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.

  17. Results of the "carbon conference" international aerosol carbon round robin test stage I

    Science.gov (United States)

    Schmid, Heidrun; Laskus, Lothar; Jürgen Abraham, Hans; Baltensperger, Urs; Lavanchy, Vincent; Bizjak, Mirko; Burba, Peter; Cachier, Helene; Crow, Dale; Chow, Judith; Gnauk, Thomas; Even, Arja; ten Brink, H. M.; Giesen, Klaus-Peter; Hitzenberger, Regina; Hueglin, Christoph; Maenhaut, Willy; Pio, Casimiro; Carvalho, Abel; Putaud, Jean-Philippe; Toom-Sauntry, Desiree; Puxbaum, Hans

    An international round robin test on the analysis of carbonaceous aerosols on quartz fiber filters sampled at an urban site was organized by the Vienna University of Technology. Seventeen laboratories participated using nine different thermal and optical methods. For the analysis of total carbon (TC), a good agreement of the values obtained by all laboratories was found (7 and 9% r.s.d.) with only two outliers in the complete data set. In contrast the results of the determination of elemental carbon (EC) in two not pre-extracted samples were highly variable ranging over more than one order of magnitude and the relative standard deviations (r.s.d.) of the means were 36.6 and 45.5%. The laboratories that obtained similar results by using methods which reduce the charring artifact were put together to a new data set in order to approach a "real EC" value. The new data set consisting of the results of 10 laboratories using seven different methods showed 16 and 24% lower averages and r.s.d. of 14 and 24% for the two not pre-extracted samples. Taking the current filters as "equivalents" for urban aerosol samples we conclude that the following methods can be used for the analysis of EC in carbonaceous aerosols: thermal methods with an optical feature to correct for charring during pyrolysis, two-step thermal procedures reducing charring during pyrolysis, the VDI 2465/1 method (removal of OC by solvent extraction and thermodesorption in nitrogen) and the VDI 2465/2 method (combustion of OC and EC at different temperatures) with an additional pre-extraction with a dimethyl formamide (DMF)/toluene mixture. Only thermal methods without any correction for charring during pyrolysis and the VDI 2465/2 method were outside the range of twice the standard deviation of the new data set. For a filter sample pre-extracted with the DMF/toluene mixture the average and r.s.d. from all laboratories (20.7 μgC; 24.4% r.s.d.) was very similar as for the laboratory set reduced to 10

  18. Emission rates of sulfur dioxide and carbon dioxide from Redoubt Volcano, Alaska during the 1989-1990 eruptions

    Science.gov (United States)

    Casadevall, T.J.; Doukas, M.P.; Neal, C.A.; McGimsey, R.G.; Gardner, C.A.

    1994-01-01

    Airborne measurements of sulfur dioxide emission rates in the gas plume emitted from fumaroles in the summit crater of Redoubt Volcano were started on March 20, 1990 using the COSPEC method. During the latter half of the period of intermittent dome growth and destruction, between March 20 and mid-June 1990, sulfur dioxide emission rates ranged from approximately 1250 to 5850 t/d, rates notably higher than for other convergent-plate boundary volcanoes during periods of active dome growth. Emission rates following the end of dome growth from late June 1990 through May 1991 decreased steadily to less than 75 t/d. The largest mass of sulfur dioxide was released during the period of explosive vent clearing when explosive degassing on December 14-15 injected at least 175,000 ?? 50,000 tonnes of SO2 into the atmosphere. Following the explosive eruptions of December 1989, Redoubt Volcano entered a period of intermittent dome growth from late December 1989 to mid-June 1990 during which Redoubt emitted a total mass of SO2 ranging from 572,000 ?? 90,000 tonnes to 680,000 ?? 90,000 tonnes. From mid-June 1990 through May 1991, the volcano was in a state of posteruption degassing into the troposphere, producing approximately 183,000 ?? 50,000 tonnes of SO2. We estimate that Redoubt Volcano released a minimum mass of sulfur dioxide of approximately 930,000 tonnes. While COSPEC data were not obtained frequently enough to enable their use in eruption prediction, SO2 emission rates clearly indicated a consistent decline in emission rates between March through October 1990 and a continued low level of emission rates through the first half of 1991. Values from consecutive daily measurements of sulfur dioxide emission rates spanning the March 23, 1990 eruption decreased in the three days prior to eruption. That decrease was coincident with a several-fold increase in the frequency of shallow seismic events, suggesting partial sealing of the magma conduit to gas loss that resulted in

  19. Carbon and sulfur cycling below the chemocline in a meromictic lake and the identification of a novel taxonomic lineage in the FCB superphylum, Candidatus Aegiribacteria

    Directory of Open Access Journals (Sweden)

    Trinity L Hamilton

    2016-04-01

    Full Text Available Mahoney Lake in British Columbia is an extreme meromictic system with unusually high levels of sulfate and sulfide present in the water column. As is common in strongly stratified lakes, Mahoney Lake hosts a dense, sulfide-oxidizing phototrophic microbial community where light reaches the chemocline. Below this ‘plate’, the euxinic hypolimnion is anoxic, eutrophic, saline, and rich in sulfide, polysulfides, elemental sulfur, and other sulfur intermediates. While much is known regarding microbial communities in sunlit portions of euxinic systems, the composition and genetic potential of organisms living at aphotic depths have rarely been studied. Metagenomic sequencing of samples from the hypolimnion and the underlying sediments of Mahoney Lake indicate that multiple taxa contribute to sulfate reduction below the chemocline and that the hypolimnion and sediments each support distinct populations of sulfate reducing bacteria (SRB different from the SRB populations observed in the chemocline. After assembling and binning the metagenomic datasets, we recovered near-complete genomes of dominant populations, including two Deltaproteobacteria. One of the deltaproteobacterial genomes encoded a 16S rRNA sequence that was most closely related to the sulfur-disproportionating genus Dissulfuribacter and the other encoded a 16S rRNA sequence that was most closely related to the fatty acid- and aromatic acid-degrading genus Syntrophus. We also recovered two near-complete genomes of Firmicutes species. Analysis of concatenated ribosomal protein trees suggests these genomes are most closely related to extremely alkaliphilic genera Alkaliphilus and Dethiobacter. Our metagenomic data indicate that these Firmicutes contribute to carbon cycling below the chemocline. Lastly, we recovered a nearly complete genome from the sediment metagenome which represents a new genus within the FCB (Fibrobacteres, Chlorobi, Bacteroidetes super phylum. Consistent with the

  20. Algae biomass as a precursor for synthesis of nitrogen-and sulfur-co-doped carbon dots: A better probe in Arabidopsis guard cells and root tissues.

    Science.gov (United States)

    Zhang, Che; Xiao, Yumei; Ma, Yongqiang; Li, Baoming; Liu, Zhidan; Lu, Cheng; Liu, Xue; Wei, Yao; Zhu, Zhangbing; Zhang, Yuanhui

    2017-09-01

    The challenge of controlling algal blooms and reusing algal biomass remain unsolved worldwide. We introduce a facile method to reuse Nannochloropsis biocrude oil (NBO) for the synthesis of nitrogen and sulfur co-doped carbon dots (N-S-C-dots). N-S-C-dots can pass through the heavily thickened wall of mature Arabidopsis thaliana (A. thaliana) guard cells because of high solubility and excellent biocompatibility. N-S-C-dots exhibit multicolor luminescence and could effectively reduce the interference of autofluorescence in plant cells by changing filters. Bioimaging of root tissues reveals that 2 major factors affect the transmission of N-S-C-dots: high osmotic pressure and intensity of cellular metabolism. This study highlights the potential application of CDs for bioimaging in plant cells and demonstrates the significance of investigating the reuse of algal biomass. Copyright © 2017. Published by Elsevier B.V.

  1. Carbon Embodied in International Trade of China and Its Emission Responsibility

    Institute of Scientific and Technical Information of China (English)

    Li Huimin; Qi Ye

    2010-01-01

    Carbon emissions embodied in international trade of China during 1997-2007 are accounted by input-output method based on Chinese input-output table and global trade analysis project database.It is revealed that carbon emissions embodied in imports and exports both increased during 1997-2007,but carbon emissions embodied in exports are greater than those embodied in imports,China is a net export nation in embodied carbon.The net exports of embodied carbon account for about 10.82% of the total carbon emissions in 1997,dropped to 7.15% in 2002,increased to13.13% in 2006,and slightly dropped to 12.64% in 2007.Low-end position of international industry division is an objective factor of being a net exporter of embodied carbon for China,and usage of a large amount of obsolete energy-using equipments wasted much energy and increased carbon emissions embodied in exports.Importers should take more responsibilities for carbon emissions embodied in trade,and China should take a certain responsibility for unreasonable energy dissipations too.

  2. Continental Announces Carbon Offsetting Program with Sustainable Travel International

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ On December 3,2007,HOUSTON,-Continental Airlines announced that it has launched acarbon offsetting program,developed in partnership with non-profit Sustainable Travel International which is a US-based non-profit organization whose mission is to promote sustainable development and responsible travel by providing programs.

  3. Research on microstructure and surface morphology of sulfur-loading active carbon%载硫活性炭微观结构和表面形态研究

    Institute of Scientific and Technical Information of China (English)

    鹿存房; 刘清才; 高威; 董凌燕

    2009-01-01

    Hg can react with sulfur to form HgS which is stable.To remove mercury in fuel gas from coal combustion plant.sulfur content in active carbon was increased by thermal deposition in this work.SEM,BET,TGA and other measurement methods were used to characterize the effect on surface morphology,sulfur distribution and specific surface.The experimental results showed that thermal deposition was effective in increasing sulfur content in active carbon:most sulfur was adhered on the carbon chain and little was on the wall of pore;specific surface was decreased though deposition and it increased with temperature increase;binding between carbonand sulfur molecular was increased.%为了增强活性炭脱除燃煤电厂烟气中汞的能力,利用汞和硫可以生成稳定的HgS的性质,研究了通过热沉淀增加了活性炭中的硫含量的改性方法,并以SEM、BET、TGA等方法,研究了改性对活性炭表面形貌、硫在活性炭中的分布、活性炭比表面积等性能的影响.结果表明,热沉淀改性方法可以增加活性炭中的硫含量;硫粘附在活性炭的炭链上量较多,孔壁较少;改性工艺降低了活性炭的比表面积,且改性活性炭的比表面积随着温度的升高而增大;载硫后,活性炭中元素硫和炭的结合被增强.

  4. Quantitative Estimation of the Climatic Effects of Carbon Transferred by International Trade.

    Science.gov (United States)

    Wei, Ting; Dong, Wenjie; Moore, John; Yan, Qing; Song, Yi; Yang, Zhiyong; Yuan, Wenping; Chou, Jieming; Cui, Xuefeng; Yan, Xiaodong; Wei, Zhigang; Guo, Yan; Yang, Shili; Tian, Di; Lin, Pengfei; Yang, Song; Wen, Zhiping; Lin, Hui; Chen, Min; Feng, Guolin; Jiang, Yundi; Zhu, Xian; Chen, Juan; Wei, Xin; Shi, Wen; Zhang, Zhiguo; Dong, Juan; Li, Yexin; Chen, Deliang

    2016-06-22

    Carbon transfer via international trade affects the spatial pattern of global carbon emissions by redistributing emissions related to production of goods and services. It has potential impacts on attribution of the responsibility of various countries for climate change and formulation of carbon-reduction policies. However, the effect of carbon transfer on climate change has not been quantified. Here, we present a quantitative estimate of climatic impacts of carbon transfer based on a simple CO2 Impulse Response Function and three Earth System Models. The results suggest that carbon transfer leads to a migration of CO2 by 0.1-3.9 ppm or 3-9% of the rise in the global atmospheric concentrations from developed countries to developing countries during 1990-2005 and potentially reduces the effectiveness of the Kyoto Protocol by up to 5.3%. However, the induced atmospheric CO2 concentration and climate changes (e.g., in temperature, ocean heat content, and sea-ice) are very small and lie within observed interannual variability. Given continuous growth of transferred carbon emissions and their proportion in global total carbon emissions, the climatic effect of traded carbon is likely to become more significant in the future, highlighting the need to consider carbon transfer in future climate negotiations.

  5. Quantitative Estimation of the Climatic Effects of Carbon Transferred by International Trade

    Science.gov (United States)

    Wei, Ting; Dong, Wenjie; Moore, John; Yan, Qing; Song, Yi; Yang, Zhiyong; Yuan, Wenping; Chou, Jieming; Cui, Xuefeng; Yan, Xiaodong; Wei, Zhigang; Guo, Yan; Yang, Shili; Tian, Di; Lin, Pengfei; Yang, Song; Wen, Zhiping; Lin, Hui; Chen, Min; Feng, Guolin; Jiang, Yundi; Zhu, Xian; Chen, Juan; Wei, Xin; Shi, Wen; Zhang, Zhiguo; Dong, Juan; Li, Yexin; Chen, Deliang

    2016-06-01

    Carbon transfer via international trade affects the spatial pattern of global carbon emissions by redistributing emissions related to production of goods and services. It has potential impacts on attribution of the responsibility of various countries for climate change and formulation of carbon-reduction policies. However, the effect of carbon transfer on climate change has not been quantified. Here, we present a quantitative estimate of climatic impacts of carbon transfer based on a simple CO2 Impulse Response Function and three Earth System Models. The results suggest that carbon transfer leads to a migration of CO2 by 0.1–3.9 ppm or 3–9% of the rise in the global atmospheric concentrations from developed countries to developing countries during 1990–2005 and potentially reduces the effectiveness of the Kyoto Protocol by up to 5.3%. However, the induced atmospheric CO2 concentration and climate changes (e.g., in temperature, ocean heat content, and sea-ice) are very small and lie within observed interannual variability. Given continuous growth of transferred carbon emissions and their proportion in global total carbon emissions, the climatic effect of traded carbon is likely to become more significant in the future, highlighting the need to consider carbon transfer in future climate negotiations.

  6. Carbonic anhydrase levels and internal lacunar CO/sub 2/ concentrations in aquatic macrophytes

    Energy Technology Data Exchange (ETDEWEB)

    Weaver, C.I.

    1979-01-01

    Carbonic anhydrase levels were examined in a variety of aquatic macrophytes from different habitats. In general, carbonic anhydrase levels increased across the habitat gradient such that activities were low in submersed aquatic macrophytes and high in emergent macrophytes with floating-leaved and free-floating plants exhibiting intermediate activities. Internal lacunar CO/sub 2/ concentrations were analyzed in relation to carbonic anhydrase activities. There was no correlation between these two parameters. Internal CO/sub 2/ concentrations ranged from low to high in submersed macrophytes, but were low in floating-leaved and emergent macrophytes. The observed internal CO/sub 2/ concentrations are discussed in relation to the individual morphologies of the plants and the environments in which they occurred.

  7. Decoupling the Impacts of Heterotrophy and Autotrophy on Sulfuric Acid Speleogenesis

    Science.gov (United States)

    Jones, A. A.; Bennett, P.

    2013-12-01

    Within caves such as Movile Caves (Romania), the Frasassi Caves (Italy), and Lower Kane Cave (LKC, Wyoming, USA) the combination of abiotic autoxidation and microbiological oxidation of H2S produces SO42- and H+ that promotes limestone dissolution through sulfuric-acid speleogenesis (SAS). Microbial sulfide oxidation by sulfur-oxidizing bacteria (SOB) has been shown recently to be the dominant process leading to speleogenesis in these caves. However, due to the inherently large diversity of microbial communities within these environments, there are a variety of metabolic pathways that can impact limestone dissolution and carbon cycling to varying degrees. In order to investigate these variations we outfitted a continuous flow bioreactor with a Picarro Wavelength-Scanned Cavity Ring Down Spectrometer (WS-CRDS) that continuously monitored and logged 12CO2 and 13CO2 at ppmv sensitivity and isotope ratios at prefers to store sulfur internally as So under these conditions, generating no acidity. The headspace was depleted in 13C when sulfur was being stored as So and enriched in 13C when sulfur was being converted to SO42-. This suggests a preference for a heterotrophy during periods of high sulfur input and autotrophy when sulfur input is low. This was corroborated by an increase in SO42- during low sulfide input and microscope images showed loss of internal sulfur within the filaments during these periods. In both monoculture and LKC environmental cultures, dissolution rates were highest when sulfur-substrate was limited and CO2 was supplied with no organic carbon. Under these conditions δ13C values were as much as 20‰ higher than abiotic conditions and signifies autotrophic carbon fixation which discriminates against 13C. 16S rRNA sequences confirm that autotrophic SOB dominate within this reactor. In contrast, when acetate was supplied with no supplied CO2, δ13C was relatively constant, maintaining values between -31‰ and as low as -37‰. This signifies

  8. COCARDE: new view on old mounds - an international network of carbonate mound research

    Science.gov (United States)

    Rüggeberg, A.; Foubert, A.; Vertino, A.; van Rooij, D.; Spezzaferri, S.; Henriet, J.-P.; Dullo, W.-C.; Cocarde Science Community

    2012-04-01

    Carbonate mounds are important contributors of life in different settings, from warm-water to cold-water environments, and throughout geological history. Research on modern cold-water coral carbonate mounds over the last decades made a major contribution to our overall understanding of these particular sedimentary systems. By looking to the modern carbonate mound community with cold-water corals as main framework builders, some fundamental questions could be addressed, until now not yet explored in fossil mound settings. The international network COCARDE (http://www.cocarde.eu) is a platform for exploring new insights in carbonate mound research of recent and ancient mound systems. The aim of the COCARDE network is to bring together scientific communities, studying Recent carbonate mounds in midslope environments in the present ocean and investigating fossil mounds spanning the whole Phanerozoic time, respectively. Scientific challenges in modern and ancient carbonate mound research got well defined during the ESF Magellan Workshop COCARDE in Fribourg, Switzerland (21.-24.01.2009). The Special Volume Cold-water Carbonate Reservoir systems in Deep Environments - COCARDE (Marine Geology, Vol. 282) was the major outcome of this meeting and highlights the diversity of Recent carbonate mound studies. The following first joint Workshop and Field Seminar held in Oviedo, Spain (16.-20.09.2009) highlighted ongoing research from both Recent and fossil academic groups integrating the message from the industry. The field seminar focused on mounds from the Carboniferous platform of Asturias and Cantabria, already intensively visited by industrial and academic researchers. However, by comparing ancient, mixed carbonate-siliciclastic mound systems of Cantabria with the Recent ones in the Porcupine Seabight, striking similarities in their genesis and processes in mound development asked for an integrated drilling campaign to understand better the 3D internal mound build-up. The

  9. A Study on capacities of activated carbon with different sulfur contents for adsorbing Mercury-Vapor in soil%不同载硫量活性炭对土壤汞蒸汽的吸附能力研究

    Institute of Scientific and Technical Information of China (English)

    廖银锋; 张军方

    2016-01-01

    活性炭由于具有较大的比表面积,可用于汞污染土壤中汞蒸汽的吸附。改性载硫活性炭利用汞的亲硫性,可有效提高汞吸附效率。本研究利用5种不同载硫量活性炭吸附汞蒸汽,考察了活性炭载硫量对汞蒸汽吸附能力的影响。研究结果表明:活性炭的载硫量与吸附能力并不呈现完全对应关系,载硫量为10%的活性炭的吸附性能最好,而20%的载硫活性炭的吸附性能最差。采用300 g的基础活性炭,5%、10%、15%及20%载硫活性炭的饱和吸附量分别为26.38、42.70、43.53及16.26 mg。%Activated carbon has a large specific surface area,which can be used to adsorb Mercury-Vapor in mercury contaminated soils. Modified activated carbon loaded by sulfur can effectively im-prove the adsorption capacity of mercury. In this study,5 groups of activated carbon loaded with dif-ferent amount of sulfur were employed for studying their adsorption capacity of mercury vapor. The results of the study show that the sulfur contents in activated carbon is not completely co-related with the adsorption capacity ,best performance in terms of adsorption capacity was witnessed as sulfur content in activated carbon is about at 10%,while worst performance was obtained as sulfur content increased to about 20%. The saturated adsorption capacities for 5%,10%,15%and 20% sulfur-loaded activated carbon(300g base activated carbon)were 26. 38mg,42. 70 mg,43. 53mg and 16. 26mg respectively.

  10. DFT, NBO and molecular docking studies of the adsorption of fluoxetine into and on the surface of simple and sulfur-doped carbon nanotubes

    Science.gov (United States)

    Shahabi, Dana; Tavakol, Hossein

    2017-10-01

    In this study, noncovalent interactions between Fluoxetine (FX) and different carbon nanotubes (CNTs) or sulfur doped carbon nanotubes (SCNTs) were fully considered using DFT, natural bond orbital (NBO) and molecular docking calculations. Two different CNTs (and SCNTs) with 7,7 and 8,8 chiralities were considered as the adsorbents and the adsorption of FX by these adsorbents were studied in two cases: into the nanotubes and on their surfaces. The results of DFT and NBO calculations proposed that the 8,8 nanotubes are more suitable adsorbents for FX because the energies of their adsorptions are minimum. Population: analyses were also proposed that the adsorption of FX by SCNTs lead to more changes in electronic and sensing properties than the adsorption by CNTs. Moreover, the adsorption energies, obtained from molecular docking calculations (using 94 different models), proposed that the adsorption of FX into (versus out of) the nanotubes, adsorption processes by double-walled or triple-walled (versus single-walled) nanotubes and the adsorption by nanotubes with 8,8 chiralities are the most favorable adsorption processes.

  11. Coastal Blue Carbon: Climate and Coastal Resilience National and International Policy Opportunities

    Science.gov (United States)

    Sutton-Grier, A.; McCarty, A.

    2014-12-01

    There is growing interest nationally and internationally in leveraging the carbon benefits (termed "blue carbon") of coastal habitats in climate and coastal resilience policies. Coastal wetlands (specifically mangroves, salt marshes, and seagrass meadows) have unique characteristics that make them incredibly efficient, natural carbon sinks with most carbon stored belowground in soils. Protecting and restoring these ecosystems around the globe will help maintain all the societal benefits these ecosystems provide including the natural climate mitigation benefits, but also the food security, water quality, and storm protection benefits that enhance coastal communities and economies. This presentation will focus on some emerging policy opportunities including: (1) incorporation of coastal wetland carbon in U.S. national climate, resilience, and conservation efforts; (2) potential steps to incorporate coastal wetlands in national greenhouse gas inventories as suggested by the 2013 International Panel on Climate Change (IPCC) Wetlands Supplement; and (3) dialogue at the United Nations Framework Convention on Climate Change (UNFCCC) about blue carbon habitats and their potential for inclusion. The presentation will conclude by highlighting some of the most pressing blue carbon scientific gaps that need to be filled in order to support these developing policies.

  12. Review of carbon materials for advanced lithium-sulfur batteries%碳质材料在锂硫电池中的应用研究进展

    Institute of Scientific and Technical Information of China (English)

    张强; 程新兵; 黄佳琦; 彭翃杰; 魏飞

    2014-01-01

    shuttle effect of polysulfides. Here, we give a brief review of recent progress on carbon/ sulfur composites, especially carbon nanotube-, graphene-and porous car-bon-based hybrids, new insights on the relationships between the structure and the electrochemical performance, and propose some important aspects for the future development of Li-S batteries.

  13. A Cable-Shaped Lithium Sulfur Battery.

    Science.gov (United States)

    Fang, Xin; Weng, Wei; Ren, Jing; Peng, Huisheng

    2016-01-20

    A carbon nanostructured hybrid fiber is developed by integrating mesoporous carbon and graphene oxide into aligned carbon nanotubes. This hybrid fiber is used as a 1D cathode to fabricate a new cable-shaped lithium-sulfur battery. The fiber cathode exhibits a decent specific capacity and lifespan, which makes the cable-shaped lithium-sulfur battery rank far ahead of other fiber-shaped batteries.

  14. Significantly improved long-cycle stability in high-rate Li-S batteries enabled by coaxial graphene wrapping over sulfur-coated carbon nanofibers.

    Science.gov (United States)

    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.

  15. Combination of cathodic reduction with adsorption for accelerated removal of Cr(VI) through reticulated vitreous carbon electrodes modified with sulfuric acid–glycine co-doped polyaniline

    Energy Technology Data Exchange (ETDEWEB)

    Mo, Xi [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082 (China); Yang, Zhao-hui, E-mail: yzh@hnu.edu.cn [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082 (China); Xu, Hai-yin; Zeng, Guang-ming; Huang, Jing; Yang, Xia; Song, Pei-pei; Wang, Li-ke [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082 (China)

    2015-04-09

    Highlights: • RVC/PANI-SA-GLY electrode was applied as a novel electrode material for accelerated removal of Cr(VI). • Faster reduction kinetics of Cr(VI) was observed by RVC/PANI-SA-GLY electrode when compared with RVC/PANI-SA and RVC electrode. • Cr(VI) removal experienced an adsorption-reduction system built by RVC/PANI-SA-GLY electrode. • The stability of RVC/PANI-SA-GLY electrode was relatively satisfactory. - Abstract: Improving the reduction kinetics is crucial in the electroreduction process of Cr(VI). In this study, we developed a novel adsorption–electroreduction system for accelerated removal of Cr(VI) by employing reticulated vitreous carbon electrode modified with sulfuric acid–glycine co-doped polyaniline (RVC/PANI-SA-GLY). Firstly, response surface methodology confirmed the optimum polymerization condition of co-doped polyaniline for modifying electrodes (Aniline, sulfuric acid and glycine, respectively, of 0.2 mol/L, 0.85 mol/L, 0.93 mol/L) when untraditional dopant glycine was added. Subsequently, RVC/PANI-SA-GLY showed higher Cr(VI) removal percentages in electroreduction experiments over RVC electrode modified with sulfuric acid doped polyaniline (RVC/PANI-SA) and bare RVC electrode. In contrast to RVC/PANI-SA, the improvement by RVC/PANI-SA-GLY was more significant and especially obvious at more negative potential, lower initial Cr(VI) concentration, relatively less acidic solution and higher current densities, best achieving 7.84% higher removal efficiency with entire Cr(VI) eliminated after 900 s. Current efficiencies were likewise enhanced by RVC/PANI-SA-GLY under quite negative potentials. Fourier transform infrared (FTIR) and energy dispersive spectrometer (EDS) analysis revealed a possible adsorption–reduction mechanism of RVC/PANI-SA-GLY, which greatly contributed to the faster reduction kinetics and was probably relative to the absorption between protonated amine groups of glycine and HCrO{sub 4}{sup −}. Eventually, the

  16. Numerical modelling of the internal mixing by coagulation of black carbon particles in aircraft exhaust

    Energy Technology Data Exchange (ETDEWEB)

    Ohlsson, S.; Stroem, J. [Stockholm Univ. (Sweden). Dept. of Meteorology

    1997-12-31

    When exhaust gases from an aircraft engine mix with ambient air the humidity may reach water saturation and water droplets will form on the available cloud condensation nuclei (CCN). It is still not resolved if the CCN, on which the cloud droplets form, are mainly particles present in the ambient air or particles emitted by the aircraft. It the exhaust from a jet engine the particles are believed to consist mainly of black carbon (BC) and sulfate. The aim is to study, with the help of a numerical model, how a two-component aerosol (i.e. BC and sulfate) in an exhaust trail may be transformed in terms of hygroscopicity by coagulation mixing and how this may depend on the sulfur content in the fuel. (R.P.) 15 refs.

  17. Sulfur Earth

    Science.gov (United States)

    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

  18. Hot and Dry Cleaning of Biomass-Gasified Gas Using Activated Carbons with Simultaneous Removal of Tar, Particles, and Sulfur Compounds

    Directory of Open Access Journals (Sweden)

    Kinya Sakanishi

    2012-05-01

    Full Text Available This study proposes a gas-cleaning process for the simultaneous removal of sulfur compounds, tar, and particles from biomass-gasified gas using Fe-supported activated carbon and a water-gas shift reaction. On a laboratory scale, the simultaneous removal of H2S and COS was performed under a mixture of gases (H2/CO/CO2/CH4/C2H4/N2/H2S/COS/steam. The reactions such as COS + H2 → H2S + CO and COS + H2O → H2S + CO2 and the water-gas shift reaction were promoted on the Fe-supported activated carbon. The adsorption capacity with steam was higher than that without steam. On a bench scale, the removal of impurities from a gas derived from biomass gasification was investigated using two activated filters packed with Fe-supported activated carbon. H2S and COS, three- and four-ring polycyclic aromatic hydrocarbons (PAHs, and particles were removed and a water-gas shift reaction was promoted through the first filter at 320–350 °C. The concentrations of H2S and COS decreased to less than 0.1 ppmv. Particles and the one- and two-ring PAHs, except for benzene, were then removed through the second filter at 60–170 °C. The concentration of tar and particles decreased from 2428 to 102 mg Nm−3 and from 2244 to 181 mg Nm−3, respectively.

  19. Natural sulfurization of carbohydrates in marine sediments : consequences for the chemical and carbon isotopic composition of sedimentary organic matter

    NARCIS (Netherlands)

    Dongen, B.E. van

    2003-01-01

    Carbohydrates make up the largest part of the organic matter in the biosphere and are used by living organism for many different reasons. They serve, among others, as carbon and energy source as well as metabolic intermediates. Carbohydrates are generally thought to be remineralized during early

  20. Troubleshooting and Exclusion of Carbon and Sulfur Analyzer%碳硫分析仪的故障检查与排除

    Institute of Scientific and Technical Information of China (English)

    梁敏鉴; 张瑞霖; 廉晓洁

    2012-01-01

    German the ELTRA carbon sulfur analyzer CS500 is applicable to the detection of powder,flakes,and turnings like a variety ofmaterials,such as coal,oil,steel,cement,soil,rubber.In the combustion process,carbon and sulfur in the sample release of SO2and CO2.Sample is usually the combustion temperature of1250°C to 1400°C.The combustion of SO2and CO2in theprinciple of detection in the pool to the infrared absorptiondetection.In the instrument will encounter many failures and phenomena need to master the instrument‘s structure andworking principle of step-by-step check and troubleshooting.Failure phenomena encountered in the course of the analysis of delay,the stove out of control,and analysis of communicationinterruption,the carrier gas flow rate decreases and infraredbattery voltage out of range,the analysis by checking the troubleshoot.%德国ELTRA碳硫分析仪CS500适用于检测粉末、片状、车屑样等各种材料,如煤炭、油品、钢、水泥、土壤、橡胶。在燃烧过程中,样品中的碳和硫释放生成SO2和CO2。试样通常的燃烧温度在1250℃到1400℃之间。燃烧生成的SO2和CO2在检测池中以红外吸收的原理进行检测。在仪器使用中会遇到很多故障,如分析延时、炉子失控、分析通信中断、载气流量降低和红外池电压超出范围等,需要通过掌握仪器的构造和工作原理逐步检查并排除故障。

  1. The role of internal variability for decadal carbon uptake anomalies in the Southern Ocean

    Science.gov (United States)

    Spring, Aaron; Hi, Hongmei; Ilyina, Tatiana

    2017-04-01

    The Southern Ocean is a major sink for anthropogenic CO2 emissions and hence it plays an essential role in modulating global carbon cycle and climate change. Previous studies based on observations (e.g., Landschützer et al. 2015) show pronounced decadal variations of carbon uptake in the Southern Ocean in recent decades and this variability is largely driven by internal climate variability. However, due to limited ensemble size of simulations, the variability of this important ocean sink is still poorly assessed by the state-of-the-art earth system models (ESMs). To assess the internal variability of carbon sink in the Southern Ocean, we use a large ensemble of 100 member simulations based on the Max Planck Institute-ESM (MPI-ESM). The large ensemble of simulations is generated via perturbed initial conditions in the ocean and atmosphere. Each ensemble member includes a historical simulation from 1850 to 2005 with an extension until 2100 under Representative Concentration Pathway (RCP) 4.5 future projections. Here we use model simulations from 1980-2015 to compare with available observation-based dataset. We found several ensemble members showing decadal decreasing trends in the carbon sink, which are similar to the trend shown in observations. This result suggests that MPI-ESM large ensemble simulations are able to reproduce decadal variation of carbon sink in the Southern Ocean. Moreover, the decreasing trends of Southern Ocean carbon sink in MPI-ESM are mainly contributed by region between 50-60°S. To understand the internal variability of the air-sea carbon fluxes in the Southern Ocean, we further investigate the variability of underlying processes, such as physical climate variability and ocean biological processes. Our results indicate two main drivers for the decadal decreasing trend of carbon sink: i) Intensified winds enhance upwelling of old carbon-rich waters, this leads to increase of the ocean surface pCO2; ii) Primary production is reduced in area

  2. Evolution of the effect of sulfur confinement in graphene-based porous carbons for use in Li-S batteries

    Science.gov (United States)

    Jia, Xiangling; Zhang, Chen; Liu, Juanjuan; Lv, Wei; Wang, Da-Wei; Tao, Ying; Li, Zhengjie; Zheng, Xiaoyu; Yu, Jong-Sung; Yang, Quan-Hong

    2016-02-01

    A controllable drying strategy is proposed for the precise and non-destructive control over the structure of a 3D graphene assembly. Such an assembly is used as a model carbon material to investigate the pore structure-dependent shuttle effect and cycling performance of the cathode of a Li-S battery.A controllable drying strategy is proposed for the precise and non-destructive control over the structure of a 3D graphene assembly. Such an assembly is used as a model carbon material to investigate the pore structure-dependent shuttle effect and cycling performance of the cathode of a Li-S battery. Electronic supplementary information (ESI) available: Experimental details and the characterization results. See DOI: 10.1039/c5nr08839a

  3. Thermodynamic and kinetic studies of the equilibration reaction between the sulfur and carbon bonded forms of a cobalt(III) complex with the ligands 1,4,7-triazycyclononane and 1,4-diaza-7-thiacyclodecane

    DEFF Research Database (Denmark)

    Song, Y.S.; Becker, J.; Kofod, Pauli

    1996-01-01

    -sulfur complex to form the alkyl complex gave 100% loss of deuterium. It is concluded that the labile methylene proton is bound to the carbon atom which in the alkyl complex is bound to cobalt(III). From the kinetic data it is estd. that the carbanion reacts with water 270 times faster than it is captured......The new cyclic thioether 1,4-diaza-7-thiacyclodecane, dathicd, has been synthesized and used for the prepn. of the sulfur- and carbon-bonded cobalt(III) complexes: [Co(tacn)(S-dathicd)]Cl3.5H2O and [Co(tacn)(C-dathicd)](ClO4)2 (tacn, 1,4,7-triazacyclononane; C-dathicd, 1,4-diamino-7-thiacyclodecan...

  4. Denitrification on internal carbon sources in RAS is limited by fibers in fecal waste of rainbow trout

    NARCIS (Netherlands)

    Meriac, A.; Eding, E.H.; Kamstra, A.; Busscher, J.P.; Schrama, J.W.; Verreth, J.A.J.

    2014-01-01

    Denitrification on internal carbon sources offers the advantage to control nitrate levels in recirculating aquaculture systems (RAS) by using the fecal carbon produced within the husbandry system. However, it is not clear to which extent fecal carbon can be utilized by the microbial community within

  5. Interfacial Reaction Dependent Performance of Hollow Carbon NanoSphere – Sulfur composite as a cathode for Li-S battery

    OpenAIRE

    Jianming eZheng; Pengfei eYan; Meng eGu; Wagner, Michael J.; Hays, Kevin A.; Junzheng eChen; Xiaohong eLi; Chongmin eWang; Jiguang eZhang; Jun eLiu; Jie eXiao

    2015-01-01

    Lithium-sulfur (Li-S) battery is a promising energy storage system due to its high energy density, cost effectiveness and environmental friendliness of sulfur. However, there are still a number of technical challenges, such as low Coulombic efficiency and poor long-term cycle life, impeding the commercialization of Li-S battery. The electrochemical performance of Li-S battery is closely related with the interfacial reactions occurring between hosting substrate and active sulfur species which ...

  6. Carbon dioxide emission and economic growth of China-the role of international trade.

    Science.gov (United States)

    Boamah, Kofi Baah; Du, Jianguo; Bediako, Isaac Asare; Boamah, Angela Jacinta; Abdul-Rasheed, Alhassan Alolo; Owusu, Samuel Mensah

    2017-05-01

    This study investigates the role of international trade in mitigating carbon dioxide emission as a nation economically advances. This study disaggregated the international trade into total exports and total imports. A multivariate model framework was estimated for the time series data for the period of 1970-2014. The quantile regression detected all the essential relationship, which hitherto, the traditional ordinary least squares could not capture. A cointegration relationship was confirmed using the Johansen cointegration model. The findings of the Granger causality revealed the presence of a uni-directional Granger causality running from energy consumption to economic growth; from import to economic growth; from imports to exports; and from urbanisation to economic growth, exports and imports. Our study established the presence of long-run relationships amongst carbon dioxide emission, economic growth, energy consumption, imports, exports and urbanisation. A bootstrap method was further utilised to reassess the evidence of the Granger causality, of which the results affirmed the Granger causality in the long run. This study confirmed a long-run N-shaped relationship between economic growth and carbon emission, under the estimated cubic environmental Kuznet curve framework, from the perspective of China. The recommendation therefore is that China as export leader should transform its trade growth mode by reducing the level of carbon dioxide emission and strengthening its international cooperation as it embraces more environmental protectionisms.

  7. The effect of gamma radiation on the ageing of sulfur cured nr/csm and nbr/csm rubber blends reinforced by carbon black

    Directory of Open Access Journals (Sweden)

    Gordana Marković

    2009-10-01

    Full Text Available In this work the effect of the γ-radiation dose on ageing of carbon black reinforced elastomeric materials was studied. The compounds based on natural rubber/chlorosulfonated rubber blend (NR/CSM and butadiene acrylonitrile rubber/chlorosulfonated rubber blend (NBR/CSM (50:50, w/w with different loadings (0, 20, 40, 50, 60, 80 and 100 phr of the filler with the average particle size of 40 nm were cured by sulfur. The obtained elastomeric composites were subjected to radiation doses (100, 200, 300 and 400 kGy in the presence of oxygen. The changes of material mechanical properties were estimated after radiation accelerated ageing. By using Fourier transform infrared measurements (ATR-FTIR it was assessed that after exposure to doses of 100 kGy alcohols, ethers, lactones, anhydrides, esters and carboxylic acids are formed in materials. The formation of shorter polyene sequences and aromatic rings in aged samples are assumed on the basis of the obtained spectra.

  8. High performance sulfur, nitrogen and carbon doped mesoporous anatase-brookite TiO₂ photocatalyst for the removal of microcystin-LR under visible light irradiation.

    Science.gov (United States)

    El-Sheikh, Said M; Zhang, Geshan; El-Hosainy, Hamza M; Ismail, Adel A; O'Shea, Kevin E; Falaras, Polycarpos; Kontos, Athanassios G; Dionysiou, Dionysios D

    2014-09-15

    Carbon, nitrogen and sulfur (C, N and S) doped mesoporous anatase-brookite nano-heterojunction titania photocatalysts have been synthesized through a simple sol-gel method in the presence of triblock copolymer Pluronic P123. XRD and Raman spectra revealed the formation of anatase and brookite mixed phases. XPS spectra indicated the presence of C, N and S dopants. The TEM images demonstrated the formation of almost monodisperse titania nanoparticles with particle sizes of approximately 10nm. N2 isotherm measurements confirmed that both doped and undoped titania anatase-brookite materials have mesoporous structure. The photocatalytic degradation of the cyanotoxin microcystin-LR (MC-LR) has been investigated using these novel nanomaterials under visible light illumination. The photocatalytic efficiency of the mesoporous titania anatase-brookite photocatalyst dramatically increased with the addition of the C, N and S non-metal, achieving complete degradation (∼ 100 %) of MC-LR. The results demonstrate the advantages of the synthetic approach and the great potential of the visible light activated C, N, and S doped titania photocatalysts for the treatment of organic micropollutants in contaminated waters under visible light.

  9. Sulfur and nitrogen binary doped carbon dots derived from ammonium thiocyanate for selective probing doxycycline in living cells and multicolor cell imaging.

    Science.gov (United States)

    Xue, Mingyue; Zhang, Liangliang; Zhan, Zhihua; Zou, Mengbing; Huang, Yong; Zhao, Shulin

    2016-04-01

    A novel sulfur and nitrogen binary doped carbon dots (S,N-CDs) was synthesized by one-step manner through the hydrothermal treatment of citric acid (CA) and ammonium thiocyanate, and the procedures for biomedical applications, including probing doxycycline in living cells and multicolor cell imaging were developed. The obtained S,N-CDs are stable in aqueous solution, possess a very high quantum yield (QY, 74.15%) and good photostability. The fluorescence of S,N-CDs can be specifically quenched by doxycycline, providing a convenient turn-off assay of doxycycline. This assay shows a wide linear detection range from 0.08 to 60 μM with a low detection limit of 20 nM. The present method also displays a good selectivity. More importantly, the S,N-CDs have an excellent biocompatibility and low cytotoxicity, allowing the multicolor cell imaging and doxycycline detection in living cells. Consequently, the developed doxycycline methods is facile, low-cost, biocompatible, sensitive and selective, which may hold the potential applications in the fields of food safety and environmental monitoring, as well as cancer therapy and related mechanism research.

  10. Double-pulse laser induced breakdown spectroscopy with ambient gas in the vacuum ultraviolet: Optimization of parameters for detection of carbon and sulfur in steel

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, X., E-mail: xi.jiang2@mail.dcu.ie [School of Physical Sciences, Dublin City University, Dublin (Ireland); National Centre for Plasma Science and Technology, Dublin City University, Dublin (Ireland); Hayden, P. [School of Physics, Atomic, Molecular and Plasma Spectroscopy Group, University College Dublin, Dublin (Ireland); Costello, J.T.; Kennedy, E.T. [School of Physical Sciences, Dublin City University, Dublin (Ireland); National Centre for Plasma Science and Technology, Dublin City University, Dublin (Ireland)

    2014-11-01

    Laser induced breakdown spectroscopy (LIBS) in the vacuum ultraviolet (VUV) has been applied to calibrated steel samples for the low concentration level detection of the light elements, carbon and sulfur in steel. Experimental optimization parameters, aimed at enhancing the sensitivity of the technique, included short wavelength spectral detection, double-pulse (DP) operation, variable focusing conditions and different ambient environments in terms of gas type and pressure. Two lasers were employed respectively as an ablation laser (Spectron: 1.06 μm/200 mJ/15 ns) and a reheating laser (Surelite: 1.06 μm/665 mJ/6 ns) in a collinear geometry. The results include insight into the most salient experimental variables and limits of detection in the parts per million range. - Highlights: • First overall optimization of TISR-LIBS in the deep VUV • First combination of double pulse VUV emission with low pressure ambient gas • The influence of each parameter on the plasm emission • Improvement of LOD for C and S in steel with optimized parameters.

  11. Interconnected nitrogen and sulfur dual-doped porous carbon as efficient electrocatalyst for triiodide reduction in dye-sensitized solar cells

    Science.gov (United States)

    Li, Zhao; Yang, Wang; Xu, Xiuwen; Tang, Yushu; Zeng, Ziwei; Yang, Fan; Zhang, Liqiang; Ning, Guoqing; Xu, Chunming; Li, Yongfeng

    2016-09-01

    Exploiting cost-effective and efficient counter electrodes (CEs) for the reduction of triiodide (I3-) has been a persistent objective for the development of dye-sensitized solar cells (DSSCs). Here, we propose a strategy for the synthesis of nitrogen and sulfur dual-doped porous carbon (N/S-PC) via a thermal annealing approach by using melamine as N source, and basic magnesium sulfate (BMS) whiskers as S source and templates. Benefiting from the high surface area, unique interconnected structural feature and synergistic effects of N/S dual-doping, the N/S-PC shows excellent electrocatalytic activity toward I3- reduction, which has simultaneously been confirmed by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and Tafel polarization measurements. The DSSC devices with N/S-PC CEs exhibit a PCE up to 7.41%, which is higher than that of DSSC devices with single heteroatom (N or S) doped CEs and even Pt CEs (7.14%).

  12. Effects of high salinity and constituent organic compounds on treatment of photo-processing waste by a sulfur-oxidizing bacteria/granular activated carbon sludge system.

    Science.gov (United States)

    Lin, Bin-Le; Hosomi, Masaaki; Murakami, Akihiko

    2002-02-01

    To achieve practical treatment of photo-processing waste (PW) using our previously proposed sulfur-oxidizing bacteria (SOB)/granular activated carbon (GAC) sludge system, this paper elucidates why 3- to 5-X dilution of PW was required. That is, a series of experiments were carried out to show the effects of high salinity and constituent organic compounds in PW, respectively. Both an inorganic salts system and calcination PW system showed that SOB completely oxidizes S2O(3)2- -S to SO(4)2- -S even at 12.3 or 13.6% salinity, respectively; hence the dilution requirement is not attributable to high salinity. In experiments employing SOB and SOB/GAC systems to investigate the effects of 23 constituent compounds in PW, compounds were classified into Groups I, II, IIIa, and IIIb. Even with 10 g/l GAC, the nine compounds in Group IIIb still exhibited a toxic effect on SOB activity at 1- and 3-X dilutions; thus it is these compounds that are responsible for requiring dilution of PW. Accordingly, a reduction in their use within the photodeveloping and fix-stabilizing industry, and/or use of > 10g/l GAC, are new considerations for establishing a more practical PW treatment process.

  13. Mercury chemisorption by sulfur adsorbed in porous materials

    NARCIS (Netherlands)

    Steijns, M.; Peppelenbos, A.; Mars, P.

    1976-01-01

    The sorption of mercury vapor by adsorbed sulfur in the zeolites CaA (= 5A) and NaX (=13X) and two types of active carbon has been measured at a temperature of 50°C. With increasing degree of micropore filling by sulfur the fraction of sulfur accessible to mercury atoms decreased for CaA and NaX.

  14. Tracing oxygen variations and its biogeochemical expression during the late hauterivian Faraoni Event: A multi tracers approach using paired carbon, nitrogen, sulfur isotopes and trace metallic elements

    Science.gov (United States)

    Thomazo, Christophe; Riquier, Laurent; Martinez, Mathieu; Mathieu, Olivier

    2013-04-01

    During the Cretaceous, several occurrences of Oceanic Anoxic Event (OAE) are described in the sedimentary record. Among them, the late Hauterivian Faraoni Event has been extensively studied in several locations including Italy, Switzerland, France and Spain and interpreted as a short-lived OAE from palaeontological, sedimentological and geochemical observations. However, the biogeochemical response to water column oxygen depletion is poorly documented and mostly stands on carbon carbonates isotopes during the Faraoni event. In order to bring further insights into the biogeochemical cycles modifications during O2 variations across the Faraoni Event, we performed an integrated geochemical study including C, N and S isotopes together with paleo-redox tracers (i.e. trace metallic elements and iron speciation) on about 25 samples from the Río Argos section (S.E. Spain). δ13Ccarb increases from 1.23‰ to 1.61‰ at the base of the studied section before the Faraoni event. Maximum values, ranging between 1.21‰ and 1.73‰, are observed within this event and are followed by a rapid decrease in δ13Ccarb values down to 0.50‰ toward the top of the section. δ13Corg and TOC values show a narrow range of variations around -26.3±0.3‰ and 0.15±0.3 wt.%, respectively. Only one sample records a higher TOC content up to 1.53 wt.% at the very base of the Faraoni Event while no sensible variations can be deduced form organic carbon isotopes. Bulk sediments nitrogen isotopes have a mean value of 2.3±0.2‰ and nitrogen contents vary between 320 and 790 ppm. A noticeable δ15N excursion (i.e. 0.86‰) is observed at the very base of the Faraoni Event and is associated with the highest TOC value. Sulfur contents vary between 100 and 2480 ppm, the highest content being recorded just bellow the base of the Faraoni Event. δ34S show a wide range of variations from -44.8 to -10.1‰ on a short scale without easily recognizable stratigraphic trend. Finally, slight increases of

  15. PREPARATION AND CORROSION RESISTANCE OF NiP/TiO2 COMPOSITE FILM ON CARBON STEEL IN SULFURIC ACID SOLUTION

    Institute of Scientific and Technical Information of China (English)

    L.Z. Song; S.Z. Song; J. Zhao

    2006-01-01

    A NiP/TiO2 composite film on carbon steel was prepared by electroless plating and sol-gel composite process. An artificial neural network was applied to optimize the prepared condition of the composite film. Corrosion behavior of the NiP/TiO2 composite film was investigated by polarization resistance measurement, anode polarization, ESEM (environmental scanning electron microscopy)and EIS (electrochemical impedance spectroscopy) measurements. Results showed that the NiP/TiO2 composite film has a good corrosion resistance in 0.5mol/L H2SO4 solution. The element valence of the composite film was characterized by XPS (X-ray photoelectron spectroscopy) spectrum, and an anticorrosion mechanism of the composite film was discussed.

  16. Synthesis of Nitrogen and Sulfur Co-doped Carbon Dots from Garlic for Selective Detection of Fe3+

    Science.gov (United States)

    Sun, Chun; Zhang, Yu; Wang, Peng; Yang, Yue; Wang, Yu; Xu, Jian; Wang, Yiding; Yu, William W.

    2016-02-01

    Garlic was used as a green source to synthesize carbon dots (CDs) with a systematic study of the optical and structure properties. Ethylenediamine was added into the synthesis to improve the photoluminescence quantum yield (PL QY) of the CDs. Detailed structural and composition studies demonstrated that the content of N and the formation of C-N and C=N were critical to improve the PL QY. The as-synthesized CDs exhibited excellent stability in a wide pH range and high NaCl concentrations, rendering them applicable in complicated and harsh conditions. Quenching the fluorescence of the CDs in the presence of Fe3+ ion made these CDs a luminescent probe for selective detection of Fe3+ ion.

  17. Thermal simulation experiments of saturated hydro-carbons with calcium sulfate and element sulfur: Implications on origin of H_2S

    Institute of Scientific and Technical Information of China (English)

    CHEN TengShui; HE Qin; LU Hong; PENG PingAn; LIU JinZhong

    2009-01-01

    Temperature-programmed simulation experiments of saturated hydrocarbons with calcium sulfate and element sulfur were compared in this study. Based on the variation analysis of the yields and evolve-ment features of gaseous hydrocarbon (C_1-C_5) and inorganic gaseous CO_2, H_2 and H_2S, the reaction mechanisms were analyzed and discussed. In the calcium sulfate-saturated hydrocarbon system, H2S was produced by a small quantity, which indicates this reaction belongs to the low-degreed thermal sulfate reduction (TSR) and is featured of self-pyrolysis. In the sulfur-saturated hydrocarbon system, the heated sulfur becomes sulfur radical, which has strong catalysis capability and can fasten the cracking of C-H bond in the alkyl group in the saturated hydrocarbons. As a result, the cracking of C-H bond leads to the yields enhancement of CO_2 and H_2, and at the same time, H2S was produced since the cracked hydrogen can be instantly combined with sulfur radical. Therefore, this reaction in the sulfur-hydrocarbon system belongs to the catalysis of sulfur radical. Furthermore, the promoted pyro-lysis effects of C_(6+). hydrocarbons by sulfur radical in the low-temperature stage in the sul-fur-hydrocarbon system, together with the consumption effects of gaseous hydrocarbon in the high-temperature stage in the calcium-hydrocarbon system, result in the crossed phenomenon of the gaseous hydrocarbon yields curves.

  18. Scoping Study. Linking RE Promotion Policies with International Carbon Trade (LINK)

    Energy Technology Data Exchange (ETDEWEB)

    Castro, Paula; Hayashi, Daisuke; Kristiansen, Kjell Olav; Michaelowa, Axel; Stadelmann, Martin

    2011-06-15

    Implementing national policies may threaten the eligibility of renewable energy projects for Clean Development Mechanism/Joint Implementation (CDM/JI), thus reducing international development financing. Countries hence need to be very careful when crafting their national promotion policies. The objectives of the Renewable Energy Technology Deployment (IEA-RETD) project were to perform a scoping study on the interplay between national Renewable Energy (RE) promotion policies and international carbon trade. The study summarizes the ongoing discussion, describes the main barriers that may hinder -- or at least not sufficiently support -- the implementation of national RE promotion policies, and provides suggestions for removing these barriers.

  19. Structural change of the porous sulfur cathode using gelatin as a binder during discharge and charge

    Energy Technology Data Exchange (ETDEWEB)

    Wang You [Department of Material Science and Engineering, Beijing University of Chemical Technology, 15 BeiSanhuan East Road, Beijing 100029 (China); Huang Yaqin [Department of Material Science and Engineering, Beijing University of Chemical Technology, 15 BeiSanhuan East Road, Beijing 100029 (China)], E-mail: huangyaqin9@sina.com; Wang Weikun [Military Power Sources Research and Development Center, Chemical Defense Institute, 35 Huayuan North Road, Beijing 100083 (China); Huang Chongjun [Department of Material Science and Engineering, Beijing University of Chemical Technology, 15 BeiSanhuan East Road, Beijing 100029 (China); Yu Zhongbao; Zhang, Hao [Military Power Sources Research and Development Center, Chemical Defense Institute, 35 Huayuan North Road, Beijing 100083 (China); Sun Jing [Department of Material Science and Engineering, Beijing University of Chemical Technology, 15 BeiSanhuan East Road, Beijing 100029 (China); Wang Anbang; Yuan Keguo [Military Power Sources Research and Development Center, Chemical Defense Institute, 35 Huayuan North Road, Beijing 100083 (China)

    2009-06-30

    The structural change of the porous sulfur cathode using gelatin as a binder was studied by means of scanning electron microscopy (SEM) and X-ray diffractometry (XRD). The original sulfur cathode exhibited a homogenous distribution of sulfur, carbon and pores. During the discharge process, the pores and elemental sulfur disappeared gradually. However, those changes were reversed and elemental sulfur was reformed after the charge process, which improved the electrochemical performance of lithium-sulfur batteries.

  20. Biologically produced sulfur

    NARCIS (Netherlands)

    Kleinjan, W.E.; Keizer, de A.; Janssen, A.J.H.

    2003-01-01

    Sulfur compound oxidizing bacteria produce sulfur as an intermediate in the oxidation of hydrogen sulfide to sulfate. Sulfur produced by these microorganisms can be stored in sulfur globules, located either inside or outside the cell. Excreted sulfur globules are colloidal particles which are stabil

  1. Carbon dioxide emissions embodied in international trade in Central Europe between 1995 and 2008

    Directory of Open Access Journals (Sweden)

    Vlčková Jana

    2015-12-01

    Full Text Available Climate change and environmental policies are widely discussed, but much less is known about emissions embodied in goods traded internationally, and the distinction between emission producers and consumers. The carbon dioxide emissions embodied in international trade in Central European countries are subject to examination in this paper. As a result of industrial restructuring and environmental legislation, air pollution has improved significantly in Central European countries since the 1989 transition. On the other hand, economic growth has been accompanied by a rise in consumerism. Despite the increasing role of exports, the Visegrad group countries have become net importers of carbon dioxide emissions between 1995 and 2008. This seems to be the ‘standard trajectory’ of a country’s transition toward a more developed and consumption-oriented economy. The global patterns of carbon dioxide emissions embodied in manufacturing exports are also mapped, using network analysis and constructing ‘product space’. The analysis confirms that industrial re-structuring played an important role in lowering the production of carbon dioxide emissions in the Visegrad countries.

  2. Sulfur respiration in a marine chemolithoautotrophic Beggiatoa strain

    Directory of Open Access Journals (Sweden)

    Anne eSchwedt

    2012-01-01

    Full Text Available The chemolithoautotrophic strain Beggiatoa sp. 35Flor shows an unusual migration behavior when cultivated in a gradient medium under high sulfide fluxes. As common for Beggiatoa spp., the filaments form a mat at the oxygen-sulfide interface. However, upon prolonged incubation, a subpopulation migrates actively downwards into the anoxic and sulfidic section of the medium, where the filaments become gradually depleted in their sulfur and polyhydroxyalkanoates (PHA inclusions. This depletion is correlated with the production of hydrogen sulfide. The sulfur- and PHA-depleted filaments return to the oxygen-sulfide interface, where they switch back to depositing sulfur and PHA by aerobic sulfide oxidation. Based on these observations we conclude that internally stored elemental sulfur is respired at the expense of stored PHA under anoxic conditions. Until now, nitrate has always been assumed to be the alternative electron acceptor in chemolithoautotrophic Beggiatoa spp. under anoxic conditions. As the medium and the filaments were free of oxidized nitrogen compounds we can exclude this metabolism. Furthermore, sulfur respiration with PHA under anoxic conditions has so far only been described for heterotrophic Beggiatoa spp., but our medium did not contain accessible organic carbon. Hence the PHA inclusions must originate from atmospheric CO2 fixed by the filaments while at the oxygen-sulfide interface. We propose that the directed migration of filaments into the anoxic section of an oxygen-sulfide gradient system is used as a last resort to preserve cell integrity, which would otherwise be compromised by excessive sulfur deposition occurring in the presence of oxygen and high sulfide fluxes. The regulating mechanism of this migration is still unknown.

  3. Microscale reservoir effects on microbial sulfur isotope fractionation

    Science.gov (United States)

    Louca, Stilianos; Crowe, Sean A.

    2017-04-01

    Microbial sulfate reduction can impart strong sulfur isotope fractionation by preferentially using the lighter 32SO42- over the heavier 34SO42-. The magnitude of fractionation depends on a number of factors, including ambient concentrations of sulfate and electron donors. Sulfur isotope compositions in sedimentary rocks thus facilitate reconstruction of past environmental conditions, such as seawater sulfate concentrations, primary productivity, organic carbon burial, and sulfur fluxes into or out of the ocean. Knowing the processes that regulate the magnitude of sulfur isotope fractionation is necessary for the correct interpretation of the geological record, but so far theoretical work has focused mostly on internal cellular processes. In sulfate-limited environments, like low sulfate lakes and the Archean ocean, microbial sulfate reduction can lead to sulfate depletion in the water column and an enrichment in isotopically heavy sulfate. This reservoir effect in turn mutes the fractionation expressed in the water column and ultimately preserved in sediments relative to the biologically induced fractionation. Here we use mathematical modeling to show that similar reservoir effects can also appear at the microscale in close proximity to sulfate-reducing cells. These microscale reservoir effects have the potential to modulate sulfur isotope fractionation to a considerable degree, especially at low (micromolar) sulfate concentrations. As a result, background sulfate concentrations, sulfate reduction rates, and extracellular ion diffusion rates can influence the fractionation expressed even if the physiologically induced fractionation is constant. This has implications for the interpretation of biogenic sulfur isotope fractionations expressed in the geological record, because the correct estimation of the environmental conditions that would promote these fractionations requires consideration of microscale reservoir effects. We discuss these implications, and

  4. An International Relations perspective on the global politics of carbon dioxide capture and storage

    Energy Technology Data Exchange (ETDEWEB)

    De Coninck, H. [Energy research Centre of the Netherlands ECN, Unit Policy Studies, Radarweg 60, 1043 NT Amsterdam (Netherlands); Baeckstrand, K. [Department of Political Science, Lund University, P.O. Box 52, 221 00 Lund (Sweden)

    2011-05-15

    With the publication of the IPCC Special Report on Carbon dioxide Capture and Storage (CCS), CCS has emerged as a focal issue in international climate diplomacy and energy collaboration. This paper has two goals. The first goal is to map CCS activities in and among various types of intergovernmental organisations; the second goal is to apply International Relations (IR) theories to explain the growing diversity, overlap and fragmentation of international organisations dealing with CCS. Which international organisations embrace CCS, and which refrain from discussing it at all? What role do these institutions play in bringing CCS forward? Why is international collaboration on CCS so fragmented and weak? We utilise realism, liberal institutionalism and constructivism to provide three different interpretations of the complex global landscape of CCS governance in the context of the similarly complicated architecture of global climate policy. A realist account of CCS's fragmented international politics is power driven. International fossil fuel and energy organisations, dominated by major emitter states, take an active role in CCS. An interest-based approach, such as liberal institutionalism, claims that CCS is part of a 'regime complex' rather than an integrated, hierarchical, comprehensive and international regime. Such a regime complex is exemplified by the plethora of international organisations with a role in CCS. Finally, constructivism moves beyond material and interest-based interpretations of the evolution of the institutionally fragmented architecture of global CCS governance. The 2005 IPCC Special Report on CCS demonstrates the pivotal role that ideas, norms and scientific knowledge have played in transforming the preferences of the international climate-change policy community.

  5. Integrated carbon dioxide/sludge gasification using waste heat from hot slags: syngas production and sulfur dioxide fixation.

    Science.gov (United States)

    Sun, Yongqi; Zhang, Zuotai; Liu, Lili; Wang, Xidong

    2015-04-01

    The integrated CO2/sludge gasification using the waste heat in hot slags, was explored with the aim of syngas production, waste heat recovery and sewage sludge disposal. The results demonstrated that hot slags presented multiple roles on sludge gasification, i.e., not only a good heat carrier (500-950 °C) but also an effective desulfurizer (800-900 °C). The total gas yields increased from 0.022 kg/kgsludge at 500 °C to 0.422 kg/kgsludge at 900 °C; meanwhile, the SO2 concentration at 900 °C remarkably reduced from 164 ppm to 114 ppm by blast furnace slags (BFS) and 93 ppm by steel slags (SS), respectively. A three-stage reaction was clarified including volatile release, char transformation and fixed carbon using Gaussian fittings and the kinetic model was analyzed. Accordingly, a decline process using the integrated method was designed and the optimum slag/sludge ratio was deduced. These deciphered results appealed potential ways of reasonable disposal of sewage sludge and efficient recovery of waste heat from hot slags.

  6. Pathways and regulation of carbon, sulfur and energy transfer in marine sediments overlying methane gas hydrates on the Opouawe Bank (New Zealand)

    Science.gov (United States)

    Dale, A. W.; Sommer, S.; Haeckel, M.; Wallmann, K.; Linke, P.; Wegener, G.; Pfannkuche, O.

    2010-10-01

    This study combines sediment geochemical analysis, in situ benthic lander deployments and numerical modeling to quantify the biogeochemical cycles of carbon and sulfur and the associated rates of Gibbs energy production at a novel methane seep. The benthic ecosystem is dominated by a dense population of tube-building ampharetid polychaetes and conspicuous microbial mats were unusually absent. A 1D numerical reaction-transport model, which allows for the explicit growth of sulfide and methane oxidizing microorganisms, was tuned to the geochemical data using a fluid advection velocity of 14 cm yr -1. The fluids provide a deep source of dissolved hydrogen sulfide and methane to the sediment with fluxes equal to 4.1 and 18.2 mmol m -2 d -1, respectively. Chemosynthetic biomass production in the subsurface sediment is estimated to be 2.8 mmol m -2 d -1 of C biomass. However, carbon and oxygen budgets indicate that chemosynthetic organisms living directly above or on the surface sediment have the potential to produce 12.3 mmol m -2 d -1 of C biomass. This autochthonous carbon source meets the ampharetid respiratory carbon demand of 23.2 mmol m -2 d -1 to within a factor of 2. By contrast, the contribution of photosynthetically-fixed carbon sources to ampharetid nutrition is minor (3.3 mmol m -2 d -1 of C). The data strongly suggest that mixing of labile autochthonous microbial detritus below the oxic layer sustains high measured rates of sulfate reduction in the uppermost 2 cm of the sulfidic sediment (100-200 nmol cm -3 d -1). Similar rates have been reported in the literature for other seeps, from which we conclude that autochthonous organic matter is an important substrate for sulfate reducing bacteria in these sediment layers. A system-scale energy budget based on the chemosynthetic reaction pathways reveals that up to 8.3 kJ m -2 d -1 or 96 mW m -2 of catabolic (Gibbs) energy is dissipated at the seep through oxidation reactions. The microorganisms mediating sulfide

  7. High performance sulfur, nitrogen and carbon doped mesoporous anatase–brookite TiO{sub 2} photocatalyst for the removal of microcystin-LR under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    El-Sheikh, Said M. [Nanostructured Materials Lab., Advanced Materials Department, CMRDI, Cairo 11421 (Egypt); Zhang, Geshan [Environmental Engineering and Science Program, Department of Biomedical, Chemical and Environmental Engineering, University of Cincinnati, Cincinnati, OH 45221 (United States); El-Hosainy, Hamza M.; Ismail, Adel A. [Nanostructured Materials Lab., Advanced Materials Department, CMRDI, Cairo 11421 (Egypt); O' Shea, Kevin E. [Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199 (United States); Falaras, Polycarpos; Kontos, Athanassios G. [Institute of Advanced Materials, Physicochemical Processes, Nanotechnology and Microsystems (IAMPPNM), National Centre for Scientific Research “Demokritos“, Agia Paraskevi Attikis, 15310 Athens (Greece); Dionysiou, Dionysios D., E-mail: dionysios.d.dionysiou@uc.edu [Environmental Engineering and Science Program, Department of Biomedical, Chemical and Environmental Engineering, University of Cincinnati, Cincinnati, OH 45221 (United States)

    2014-09-15

    Graphical abstract: - Highlights: • Synthesis of tailor-designed C, N and S doped titania anatase–brookite nano-heterojunction photocatalyst. • Microcystin-LR was completely removed in the presence of doped sample under visible light. • The MC-LR degradation rate achieved by the doped sample was much better than that of un-doped sample under visible light. - Abstract: Carbon, nitrogen and sulfur (C, N and S) doped mesoporous anatase–brookite nano-heterojunction titania photocatalysts have been synthesized through a simple sol–gel method in the presence of triblock copolymer Pluronic P123. XRD and Raman spectra revealed the formation of anatase and brookite mixed phases. XPS spectra indicated the presence of C, N and S dopants. The TEM images demonstrated the formation of almost monodisperse titania nanoparticles with particle sizes of approximately 10 nm. N{sub 2} isotherm measurements confirmed that both doped and undoped titania anatase–brookite materials have mesoporous structure. The photocatalytic degradation of the cyanotoxin microcystin-LR (MC-LR) has been investigated using these novel nanomaterials under visible light illumination. The photocatalytic efficiency of the mesoporous titania anatase–brookite photocatalyst dramatically increased with the addition of the C, N and S non-metal, achieving complete degradation (∼100%) of MC-LR. The results demonstrate the advantages of the synthetic approach and the great potential of the visible light activated C, N, and S doped titania photocatalysts for the treatment of organic micropollutants in contaminated waters under visible light.

  8. Collagen-biomorphic porous carbon nanofiber monoliths: Biosilicification-assisted sustainable synthesis and application in Li-S battery

    Science.gov (United States)

    Hu, Wen; Shen, Tao; Hou, Hongying; Gan, Guoyou; Zheng, Biju; Li, Fengxian; Yi, Jianhong

    2016-12-01

    Monolithic carbon has been synthesized via a sustainable biomimetic route utilizing intrafibrillar silicified collagen sponge as precursor and morphogenesis template. The mineralized silica in the biohybrid prevents collapse of the carbon during pyrolysis. Upon biosilica removal results show that the carbon monoliths inherit the porous fiber structure of the mother collagen. The carbon nanofiber framework facilitates the construction of a high electrical conductive pathway, while the internal spaces developed among the intertwined fibrillar network and pores within nanofiber walls offer room for sulfur storage. The as-obtained carbon-sulfur cathode exhibits an accessible discharge capacity approaching 800mAh g-1 in Li-S battery.

  9. Assessment of the stoichiometry and efficiency of CO2 fixation coupled to reduced sulfur oxidation

    NARCIS (Netherlands)

    Klatt, Judith M.; Polerecky, Lubos

    2015-01-01

    Chemolithoautotrophic sulfur oxidizing bacteria (SOB) couple the oxidation of reduced sulfur compounds to the production of biomass. Their role in the cycling of carbon, sulfur, oxygen, and nitrogen is, however, difficult to quantify due to the complexity of sulfur oxidation pathways. We describe a

  10. Assessment of the stoichiometry and efficiency of CO2 fixation coupled to reduced sulfur oxidation

    NARCIS (Netherlands)

    Klatt, Judith M.; Polerecky, Lubos|info:eu-repo/dai/nl/370827929

    2015-01-01

    Chemolithoautotrophic sulfur oxidizing bacteria (SOB) couple the oxidation of reduced sulfur compounds to the production of biomass. Their role in the cycling of carbon, sulfur, oxygen, and nitrogen is, however, difficult to quantify due to the complexity of sulfur oxidation pathways. We describe a

  11. 层次孔活性炭气凝胶/硫复合正极材料的制备及其电化学性能%Preparation and electrochemical performance of a hierarchically porous activated carbon aerogel/sulfur cathode for lithium-sulfur batteries

    Institute of Scientific and Technical Information of China (English)

    唐志伟; 徐飞; 梁业如; 吴丁财; 符若文

    2015-01-01

    An activated carbon aerogel with a hierarchical pore structure was prepared through KOH activation with a KOH/organ-ic aerogel with mass ratio 3:1, followed by carbonization at 900 ℃ for 3 h. The activated carbon aerogel was used as a conductive host of elemental sulfur to prepare a composite by a melt-infiltration method. Nitrogen adsorption, SEM, TEM, XRD and XPS were used to characterize the structure and morphology of the samples before and after the sulfur infiltration. Cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy were used to evaluate the electrochemical performance of the composite as a cathode in lithium ion batteries. It is found that the composite has a sulfur content of up to 66. 2%, a high initial discharge capacity of 1 287 mAh·g-1 at a current density of 0. 2 C and a retained capacity of 643 mAh·g-1 after 200 cycles, which are much higher than those of a sulfur cathode without the carbon host. The composite also exhibits excellent rate capability.%以有机气凝胶RC-500为原料,采用低质量比KOH(KOH:有机气凝胶=3:1)活化的方法,900℃炭化活化,制备出一种具有层次孔结构的活性炭气凝胶ACA-500-3。将其作为硫载体,与单质硫在155℃熔融复合后制备出含硫量达66.2%的锂硫电池正极复合材料( ACA-500-3-S)。通过N2吸附、SEM、TEM、XRD和XPS等测试手段考察ACA-500-3和ACA-500-3-S的结构和形貌,并利用循环伏安、恒流充放电和交流阻抗等方法研究ACA-500-3-S的电化学性能。 ACA-500-3-S在0.2 C(1 C=1675 mA·g-1)电流密度下,初始放电比容量高达1287 mAh·g-1,200圈后比容量保持在643 mAh·g -1,并表现出良好的倍率性能,明显优于单质硫电极。

  12. Controversy of International Carbon-motivated Border Tax Adjustment and Its Impact on China's Manufacturing Industries%Controversy of International Carbon-motivated Border Tax Adjustment and Its Impact on China's Manufacturing Industries

    Institute of Scientific and Technical Information of China (English)

    Shen Keting

    2011-01-01

    Carbon-motivated border tax adjustment (BTA) aims to compensate for the loss of competitiveness of carbon intensive products due to carbon dioxide abatement actions. Based on the analysis of the international background of carbon-motivated BTAs, this paper discusses the fundamental motivation leading to US policy transformation, the potential impacts of the policy on China's manufacturing industries, and the compatibility of the policy to WTO rules. Carbon-motivated BTAs violate the fundamental principle of the UNFCCC, and potentially conflict with the core WTO principle of non-discrimination reflected in the GATT Articles 1 and III. However, Article XX of the GATT may be applicable. Thus, the author suggests several measures to alleviate the impacts of carbon-motivated BTAs, and puts forward countermeasures based on carbon consumption per capita.

  13. Protected Sulfur Cathode with Mixed Conductive Coating Layer for Lithium Sulfur Battery

    Science.gov (United States)

    Jin, Jun; Wen, Zhaoyin; Wang, Qingsong; Gu, Sui; Huang, Xiao; Chen, Chunhua

    2016-10-01

    A mixed conductive coating layer composed of lithium ion conductive ceramic powder, carbon and binder was introduced on the surface of a sulfur electrode. This coating layer is designed to suppress the migration of lithium polysulfides from the sulfur electrode, and improve the cycling capacity of a lithium sulfur battery. The protected sulfur cathode with a mixed conductive coating layer delivered an initial specific capacity of 1236 mAh g-1 at 0.5C and maintained a capacity of 842 mAh g-1 after 100 cycles. In particular, a soft package battery with protected cathode exhibits improved cycling capacity and excellent rate performance.

  14. Sulfur Poisoning of Ni/stabilized-zirconia Anodes – Effect on Long-Term Durability

    DEFF Research Database (Denmark)

    Hauch, Anne; Hagen, Anke; Hjelm, Johan

    2013-01-01

    Sulfur impurities in carbon containing fuels for solid oxide fuel cells (SOFC), e.g. natural gas and biogas, can lead to significant losses in performance due to the sulfur sensitivity of Ni/YSZ SOFC anodes. Full cells having Ni/YSZ and Ni/ScYSZ anodes have been characterized during long......-term galvanostatic operation in internal reforming gas mixture (CH4/H2O/H2:30/60/10), with 2 ppm H2S exposure to the anode, at different current densities. The aim was not only to investigate the well-known initial performance drop associated with adsorbed sulfur in the Ni/stabilized-zirconia anodes, but also...

  15. Preparation of Graphene Coated Carbon Nanotube-Sulfur Composite and Its Performance for Lithium-Sulfur Battery%石墨烯包覆碳纳米管-硫(CNT-S)复合材料及锂硫电池性能

    Institute of Scientific and Technical Information of China (English)

    郑加飞; 郑明波; 李念武; 吕洪岭; 邱兰; 曹洁明; 姬广斌

    2013-01-01

    针对锂硫电池研究与实际应用中遇到的主要问题,本文通过一种简单有效的水热法还原氧化石墨烯对商用碳纳米管-硫(CNT-S)纳米复合材料进行包覆,形成一种可有效抑制多硫聚合物扩散的石墨烯包覆结构.X射线衍射(XRD),扫描电子显微镜(SEM)表征结果表明硫均匀地负载在碳纳米管上,并且在CNT-S复合材料外表面包覆有一层石墨烯.电化学测试结果表明,这种包覆结构能显著提高CNT-S复合材料的锂硫电池性能.%To solve the main problems encountered in the lithium-sulfur battery research and practical application,a simple and effective hydrothermal reduction of graphene oxide was employed to encapsulate commercial carbon nanotube-sulfur (CNT-S) nanocomposite in this study,then an effective type of graphene coated CNT-S nanostructure was formed.The polysulphide anions diffusion phenomenon was effectively restrained by the graphene coating structure.The nanocomposites were characterized by X-ray diffraction and scanning electron microscope.The results indicated that elemental sulfur was uniformly distributed across the CNT,and a layer of graphene coated on the surface of CNT-S nanocomposite.The electrochemical test results showed that the graphene coating nanostructure obviously improved the lithium-sulfur battery performance of the CNT-S nanocomposite.

  16. Thiophenic Sulfur Compounds Released During Coal Pyrolysis

    Science.gov (United States)

    Xing, Mengwen; Kong, Jiao; Dong, Jie; Jiao, Haili; Li, Fan

    2013-01-01

    Abstract Thiophenic sulfur compounds are released during coal gasification, carbonization, and combustion. Previous studies indicate that thiophenic sulfur compounds degrade very slowly in the environment, and are more carcinogenic than polycyclic aromatic hydrocarbons and nitrogenous compounds. Therefore, it is very important to study the principle of thiophenic sulfur compounds during coal conversion, in order to control their emission and promote clean coal utilization. To realize this goal and understand the formation mechanism of thiophenic sulfur compounds, this study focused on the release behavior of thiophenic sulfur compounds during coal pyrolysis, which is an important phase for all coal thermal conversion processes. The pyrolyzer (CDS-5250) and gas chromatography–mass spectrometry (Focus GC-DSQII) were used to analyze thiophenic sulfur compounds in situ. Several coals with different coal ranks and sulfur contents were chosen as experimental samples, and thiophenic sulfur compounds of the gas produced during pyrolysis under different temperatures and heating rates were investigated. Levels of benzothiophene and dibenzothiophene were obtained during pyrolysis at temperatures ranging from 200°C to 1300°C, and heating rates ranging from 6°C/ms to 14°C/ms and 6°C/s to 14°C/s. Moreover, the relationship between the total amount of benzothiophene and dibenzothiophene released during coal pyrolysis and the organic sulfur content in coal was also discussed. This study is beneficial for understanding the formation and control of thiophenic sulfur compounds, since it provides a series of significant results that show the impact that operation conditions and organic sulfur content in coal have on the amount and species of thiophenic sulfur compounds produced during coal pyrolysis. PMID:23781126

  17. The missing link in an international framework for carbon pricing: border adjustment with taxes or allowances

    DEFF Research Database (Denmark)

    Andersen, Mikael Skou

    2017-01-01

    was created at the initiative of the World Bank and the International Monetary Fund. Over the past five years the share of global CO2 emissions subject to carbon pricing via either taxes or allowances have tripled, from four to twelve per cent. In anticipation of a widening gap between countries the scope...... allow for such adjustment under its exemption mechanisms and when all other options have been exhausted. As a highly sensitive measure, not only the complex technical and legal questions deserve attention, but also how to make the best diplomacy of it within the arsenal of climate change mitigation...

  18. Evaluation and Certification of Ambersorb 4652 for use in Activated Carbon Ion Exchange Filters for the International Space Station

    Science.gov (United States)

    Adam, Niklas; Cox, Trey; Larner, Katherine; Carter, Donald; Kouba, Coy

    2017-01-01

    In order to reduce the infiltration of dimethylsilanediol (DMSD) and other organosilicon containing species through the Multifiltration Beds (MF Beds), an alternate activated carbon was found to replace the obsolete Barnabey Cheney 580-26 activated carbon. The carbon that removed the most organosilicon compounds in testing1 was a synthetic activated carbon named Schunk 4652 which later became Ambersorb 4652. Since activated carbon has a large capacity for iodine (I2), and is used in the Activated Carbon Ion Exchange (ACTEX) filters on the International Space Station (ISS), testing was performed on the Ambersorb 4652 carbon to determine the effectiveness of the material for use in ACTEX filters to remove iodine. This work summarizes the testing and the certification of Ambersorb 4652 for use in the ACTEX filters for the ISS.

  19. Carbon emissions from international cruise ship passengers' travel to and from New Zealand

    Energy Technology Data Exchange (ETDEWEB)

    Howitt, Oliver J.A.; Revol, Vincent G.N.; Smith, Inga J.; Rodger, Craig J. [Department of Physics, University of Otago, PO Box 56, Dunedin (New Zealand)

    2010-05-15

    Greenhouse gas emissions from international transport contribute to anthropogenic global warming, yet these emissions are not liable under the Kyoto Protocol. International attention is being given to quantifying such emissions. This paper presents the results of research into international cruise ship journeys to and from New Zealand. CO{sub 2} emissions from such journeys were calculated using an activity based, or 'bottom-up', model. Emissions factors for individual journeys by cruise ships to or from New Zealand in 2007 ranged between 250 and 2200 g of CO{sub 2} per passenger-kilometre (g CO{sub 2} per p-km), with a weighted mean of 390 g CO{sub 2} per p-km. The weighted mean energy use per passenger night for the 'hotel' function of these cruise vessels was estimated as 1600 MJ per visitor night, 12 times larger than the value for a land-based hotel. Using a simple price elasticities calculation, international cruise journeys for transport purposes were found to have a greater relative decrease in demand than plane journeys when the impact of carbon pricing was analysed. The potential to decrease the CO{sub 2} emissions per p-km was examined, and if passenger accommodation was compacted and some luxury amenities dispensed with values similar to those of economy-class air travel were obtained. (author)

  20. Flexible and internal series-connected supercapacitors with high working voltage using ultralight porous carbon nanofilms

    Science.gov (United States)

    Li, Xiaoyan; Zhou, Man; Wang, Jun; Ge, Fengyan; Zhao, Yaping; Komarneni, Sridhar; Cai, Zaisheng

    2017-02-01

    Highly flexible carbon nanofibers with hierarchical nanostructure, which provide an excellent distribution of differently functionalized-carbon nanotubes and terephthalic acid, were prepared cost-effectively and demonstrated as binder-free electrodes. Symmetric solid-state supercapacitors were then fabricated and could be operated reversibly in the voltage range of 0-1.8 V with excellent electrochemical performance due to the hierarchical porosity and hybrid architecture. Furthermore, internal series-connected supercapacitors based on the prepared porous carbon nanofibers were designed and fabricated. Such supercapacitors were found to be flexible enough to be rolled up or twisted with constant capacitive performance at a high working voltage of up to 3.6 V and exhibited a 38.9% increase in energy density than that of the single-cell supercapacitor. This one-step approach leads to simplicity of operation and economical efficiency for fabricating lightweight supercapacitors with high working voltage and energy density, which may be beneficial for the development of flexible and wearable energy storage devices.

  1. CGE Simulation for Levying Carbon Tax in China and International Experience of Levying Carbon Tax%CGE Simulation for Levying Carbon Tax in China and International Experience of Levying Carbon Tax

    Institute of Scientific and Technical Information of China (English)

    Zhang Mingxi

    2011-01-01

    Levying carbon tax is conducive to reducing carbon dioxide emissions and protecting the environment. The author firstly reviewed some relevant empirical studies on carbon tax both home and abroad, and then established the CGE model and simulated levying carbon tax in China. The study found that levying carbon tax would have little impact on China's economy: in a short-term, China's GDP might decrease by 0.51%, while in a long-term it might decrease by 0.08%; however, the carbon dioxide emissions would be substantially reduced. Meanwhile, levying carbon tax has some negative impact on the output of each industry in the very economic structure; of this, the mineral extractive industries would be influenced the most. Then the author summarized experience of levying carbon tax in foreign countries.

  2. Sulfur cycle

    Digital Repository Service at National Institute of Oceanography (India)

    LokaBharathi, P.A.

    :1, the reductive assimilation of sulfate is less important than nitrate. Assimilatory reduction is common among organisms and does not lead to the production of sulfide. The eight-electron reduction of sulfate to sulfide pro- ceeds in different stages. As the ion...; Biogeochemical Approaches to Environmental Risk Assessment; Biogeochemical Models; Biomagnification; Carbon Cycle; Classification and Regression Trees; Climate Change 1: Short-Term Dynamics; Constructed Wetlands, Subsurface Flow; Constructed Wetlands, Surface...

  3. 煤基直接碳燃料电池硫处理工艺探索%The explore of sulfur treatment technology for coal-based direct carbon fuel cell

    Institute of Scientific and Technical Information of China (English)

    毕文彦; 万剑峰; 蒋荣立

    2014-01-01

    Coal is the main energy in our country. As a main forms of energy production,coal power plants produces a large amount noxious gases with greenhouse gas CO2 ,sulfur compounds,and so on. Theoretical value of the coal-based direct carbon fuel cells thermodynamic efficiency is closed to 100% and it can re-alize CO2 zero-emission. It’s the key energy utilization technology of high efficiency and low carbon emis-sion. The industrial application of the battery is restricted by the sulfur poisoning. The complex desulfu-rization process(PCESTO)for raw coal,consisted of gravity flotation,chemical oxidation,electrochemical oxidation,ionic liquid extraction,solvent extraction and rising temperature. PCESTE can effectively reduce the content of sulfur in coal and remove convert poisonous sulfur into the non-poisonous one in the direct carbon fuel cell.%煤炭是我国的主要能源,以燃烧煤为主的煤炭利用过程产生了大量的温室气体 CO2、含硫化合物气体等。通过煤基直接碳燃料电池发电,理论热力学效率接近100%,而且可以实现 CO2的零排放,是煤高效、低碳洁净利用的关键技术,其大规模推广应用却受到原煤含硫化合物引起的硫中毒的制约。通过对现有煤脱硫工艺进行分析,提出洗选→化学氧化→电化学氧化→离子液体萃取→溶剂萃取→高温固硫(PCESTO)阶段联合处理工艺对原煤进行脱硫处理,可以有效降低煤中硫含量,定向转化直接碳燃料电池中硫的存在形式,减少和消除硫对直接碳燃料电池电极的毒化作用。

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

    Science.gov (United States)

    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.

  5. CarboNA: International Studies of the North American Carbon Cycle

    Science.gov (United States)

    Denning, S.; Cavallaro, N.; Ste-Marie, C.; Muhlia-Melo, A.

    2009-05-01

    A Science Steering Committee has been formed consisting of carbon cycle scientists from Canada, Mexico, and the United States and government agency contacts from each country, to draft a Science Plan for CarboNA. Science questions that we will address include: 1. What's the current carbon budget of NA and adjacent oceans, including spatial structure and seasonal-to- interannual variations? 2. What mechanisms are involved? What processes control the time mean vs the interannual variability? 3. When will sinks saturate? Will they become sources? Are there surprises in store? What roles will be played by melting permafrost, boreal warming, and subtropical desertification, and tropical development? 4. What are the likely responses of terrestrial ecosystems and coastal oceans to climate change and enhanced CO2? 5. What roles will economic development, energy technology, and trade play in mitigating increases in fossil fuel emissions? In addition to the national research programs already underway in the three countries, we anticipate special collaborative projects of international scope. For example: 1. Studies of the response of terrestrial ecosystems to climate change along an ecological gradient from the Arctic to the Tropics; 2. Truly continental budgets for atmospheric greenhouse gases using data from land-based, airborne, marine, and spaceborne platforms; 3. An aggressively interdisciplinary intensive experiment to understand and quantify carbon cycle processes and budgets in the Gulf of Mexico Basin; 4. Investigation of the turrent state and likely future changes in carbon cycling in coastal ocean environments, including river inputs of POC, DOC, DIC, and nutrients; impacts on fisheries and coastal economies; exchange between coastal oceans and deep ocean basins; and air-sea gas exchange; 5. Government-level agreements on data sharing and harmonization, including but not limited to forest inventories, agricultural data, fossil fuel emissions data, land-use data

  6. Solubility of Sulfur Dioxide in Sulfuric Acid

    Science.gov (United States)

    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.

  7. Is a Clean Development Mechanism project economically justified? Case study of an International Carbon Sequestration Project in Iran.

    Science.gov (United States)

    Katircioglu, Salih; Dalir, Sara; Olya, Hossein G

    2016-01-01

    The present study evaluates a carbon sequestration project for the three plant species in arid and semiarid regions of Iran. Results show that Haloxylon performed appropriately in the carbon sequestration process during the 6 years of the International Carbon Sequestration Project (ICSP). In addition to a high degree of carbon dioxide sequestration, Haloxylon shows high compatibility with severe environmental conditions and low maintenance costs. Financial and economic analysis demonstrated that the ICSP was justified from an economic perspective. The financial assessment showed that net present value (NPV) (US$1,098,022.70), internal rate of return (IRR) (21.53%), and payback period (6 years) were in an acceptable range. The results of the economic analysis suggested an NPV of US$4,407,805.15 and an IRR of 50.63%. Therefore, results of this study suggest that there are sufficient incentives for investors to participate in such kind of Clean Development Mechanism (CDM) projects.

  8. Effect of an Internal Heat Exchanger on Performance of the Transcritical Carbon Dioxide Refrigeration Cycle with an Expander

    OpenAIRE

    Zhenying Zhang; Lili Tian; Yanhua Chen; Lirui Tong

    2014-01-01

    The effect of the internal heat exchanger (IHE) on the performance of the transcritical carbon dioxide refrigeration cycle with an expander is analyzed theoretically on the basis of the first and second laws of thermodynamics. The possible parameters affecting system efficiency such as heat rejection pressure, gas cooler outlet temperature, evaporating temperature, expander isentropic efficiency and IHE effectiveness are investigated. It is found that the IHE addition in the carbon dioxide re...

  9. Estimation of Surface Temperature and Heat Flux by Inverse Heat Transfer Methods Using Internal Temperatures Measured While Radiantly Heating a Carbon/Carbon Specimen up to 1920 F

    Science.gov (United States)

    Pizzo, Michelle; Daryabeigi, Kamran; Glass, David

    2015-01-01

    The ability to solve the heat conduction equation is needed when designing materials to be used on vehicles exposed to extremely high temperatures; e.g. vehicles used for atmospheric entry or hypersonic flight. When using test and flight data, computational methods such as finite difference schemes may be used to solve for both the direct heat conduction problem, i.e., solving between internal temperature measurements, and the inverse heat conduction problem, i.e., using the direct solution to march forward in space to the surface of the material to estimate both surface temperature and heat flux. The completed research first discusses the methods used in developing a computational code to solve both the direct and inverse heat transfer problems using one dimensional, centered, implicit finite volume schemes and one dimensional, centered, explicit space marching techniques. The developed code assumed the boundary conditions to be specified time varying temperatures and also considered temperature dependent thermal properties. The completed research then discusses the results of analyzing temperature data measured while radiantly heating a carbon/carbon specimen up to 1920 F. The temperature was measured using thermocouple (TC) plugs (small carbon/carbon material specimens) with four embedded TC plugs inserted into the larger carbon/carbon specimen. The purpose of analyzing the test data was to estimate the surface heat flux and temperature values from the internal temperature measurements using direct and inverse heat transfer methods, thus aiding in the thermal and structural design and analysis of high temperature vehicles.

  10. Quantitative Analysis of Carbon Steel with Multi-Line Internal Standard Calibration Method Using Laser-Induced Breakdown Spectroscopy.

    Science.gov (United States)

    Pan, Congyuan; Du, Xuewei; An, Ning; Zeng, Qiang; Wang, Shengbo; Wang, Qiuping

    2016-04-01

    A multi-line internal standard calibration method is proposed for the quantitative analysis of carbon steel using laser-induced breakdown spectroscopy (LIBS). A procedure based on the method was adopted to select the best calibration curves and the corresponding emission lines pairs automatically. Laser-induced breakdown spectroscopy experiments with carbon steel samples were performed, and C, Cr, and Mn were analyzed via the proposed method. Calibration curves of these elements were constructed via a traditional single line internal standard calibration method and a multi-line internal standard calibration method. The calibration curves obtained were evaluated with the determination coefficient, the root mean square error of cross-validation, and the average relative error of cross-validation. All of the parameters were improved significantly with the proposed method. The results show that accurate and stable calibration curves can be obtained efficiently via the multi-line internal standard calibration method. © The Author(s) 2016.

  11. Multiple scattering of light by water cloud droplets with external and internal mixing of black carbon aerosols

    Institute of Scientific and Technical Information of China (English)

    Wang Hai-Hua; Sun Xian-Ming

    2012-01-01

    The mixture of water cloud droplets with black carbon impurities is modeled by external and internal mixing models.The internal mixing model is modeled with a two-layered sphere(water cloud droplets containing black carbon(BC)inclusions),and tihe single scattering and absorption characteristics are calculated at the visible wavelength of 0.55 μm by using the Lorenz Mie theory.The external mixing model is developed assuming that the same amount of BC particles are mixed with the water droplets externally.The multiple scattering characteristics we computed by using the Monte Carlo method.The results show that when the size of the BC aerosol is small,the reflection intensity of the internal mixing model is bigger than that of the external mixing model.However,if the size of the BC aerosol is big,the absorption of the internal mixing model will be larger than that of the external mixing model.

  12. Sulfur and Hydrogen Isotope Anomalies in Meteorite Sulfonic Acids

    Science.gov (United States)

    Cooper, George W.; Thiemens, Mark H.; Jackson, Teresa L.; Chang, Sherwood

    1997-01-01

    Intramolecular carbon, hydrogen, and sulfur isotope ratios were measured on a homologous series of organic sulfonic acids discovered in the Murchison meteorite. Mass-independent sulfur isotope fractionations were observed along with high deuterium/hydrogen ratios. The deuterium enrichments indicate formation of the hydrocarbon portion of these compounds in a low-temperature environment that is consistent with that of interstellar clouds. Sulfur-33 enrichments observed in methanesulfonic acid could have resulted from gas-phase ultraviolet irradiation of a precursor, carbon disulfide. The source of the sulfonic acid precursors may have been the reactive interstellar molecule carbon monosulfide.

  13. Genetic engineering of sulfur-degrading Sulfolobus

    Energy Technology Data Exchange (ETDEWEB)

    Ho, N.W.Y. (Purdue Univ., Lafayette, IN (USA). Lab. of Renewable Resources Engineering)

    1990-01-01

    Recent studies have shown that some microorganisms can play a significant role in removing the sulfur compounds from coal. Sulfolobus acidocaldarius is one such microorganism. Some microorganisms can remove only organic sulfur from coal, other can remove only inorganic sulfur from coal, but S. acidocaldarius seems to be able to remove both the organic and the inorganic sulfur from coal. Furthermore, S. acidocaldarius has been shown to be able to use the sulfur and carbon derived from coal as its sole carbon and energy source for growth. These properties make this microorganism unique for coal desulfurization. This project is aimed at applying recombinant DNA techniques to improve the capability of S. acidocaldarius for coal desulfurization, which includes making it the host for housing foreign genes that encode the most effective enzymes for coal desulfurization. Since there is no established vectors and procedures for introducing vectors into S. acidocaldarius and related microorganisms, the immediate goal is to establish a gene cloning system for this species. During the present quarter, the authors have studied a few systems which can be used as the potential selection mechanism for the selection of the desired transformants. In addition, they also analyzed the extracellular proteins from S. acidocaldarius as well as other potential organic sulfur removing species and also managed to obtain most strains and plasmids that are needed for this work. Results to date are given. 1 tab.

  14. Sulfuric acid on Europa and the radiolytic sulfur cycle

    Science.gov (United States)

    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.

  15. Towards Stable Lithium-Sulfur Batteries with a Low Self-Discharge Rate: Ion Diffusion Modulation and Anode Protection.

    Science.gov (United States)

    Xu, Wen-Tao; Peng, Hong-Jie; Huang, Jia-Qi; Zhao, Chen-Zi; Cheng, Xin-Bing; Zhang, Qiang

    2015-09-01

    The self-discharge of a lithium-sulfur cell decreases the shelf-life of the battery and is one of the bottlenecks that hinders its practical applications. New insights into both the internal chemical reactions in a lithium-sulfur system and effective routes to retard self-discharge for highly stable batteries are crucial for the design of lithium-sulfur cells. Herein, a lithium-sulfur cell with a carbon nanotube/sulfur cathode and lithium-metal anode in lithium bis(trifluoromethanesulfonyl)imide/1,3-dioxolane/dimethyl ether electrolyte was selected as the model system to investigate the self-discharge behavior. Both lithium anode passivation and polysulfide anion diffusion suppression strategies are applied to reduce self-discharge of the lithium-sulfur cell. When the lithium-metal anode is protected by a high density passivation layer induced by LiNO3 , a very low shuttle constant of 0.017 h(-1) is achieved. The diffusion of the polysulfides is retarded by an ion-selective separator, and the shuttle constants decreased. The cell with LiNO3 additive maintained a discharge capacity of 97 % (961 mAh g(-1) ) of the initial capacity after 120 days at open circuit, which was around three times higher than the routine cell (32 % of initial capacity, corresponding to 320 mAh g(-1) ). It is expected that lithium-sulfur batteries with ultralow self-discharge rates may be fabricated through a combination of anode passivation and polysulfide shuttle control, as well as optimization of the lithium-sulfur cell configuration.

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

    Science.gov (United States)

    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.

  17. Thermodynamic and kinetic studies of the equilibration reaction between the sulfur and carbon bonded forms of a cobalt(III) complex with the ligands 1,4,7-triazycyclononane and 1,4-diaza-7-thiacyclodecane

    DEFF Research Database (Denmark)

    Song, Y.S.; Becker, J.; Kofod, Pauli

    1996-01-01

    The new cyclic thioether 1,4-diaza-7-thiacyclodecane, dathicd, has been synthesized and used for the prepn. of the sulfur- and carbon-bonded cobalt(III) complexes: [Co(tacn)(S-dathicd)]Cl3.5H2O and [Co(tacn)(C-dathicd)](ClO4)2 (tacn, 1,4,7-triazacyclononane; C-dathicd, 1,4-diamino-7-thiacyclodecan......-8-ide anion). A thermodn. and kinetic study of the equilibration between these coordination compds. has been performed using UV-VIS absorption spectroscopy, IE-HPLC and 13C NMR ([OH-]=10-5-1.0 M, T=25.0 DegC, I=1.0 M). In basic soln. Co(tacn)(S-dathicd)3+ deprotonates at one of the coordinated amine...

  18. A compilation of sulfur dioxide and carbon dioxide emission-rate data from Cook Inlet volcanoes (Redoubt, Spurr, Iliamna, and Augustine), Alaska during the period from 1990 to 1994

    Science.gov (United States)

    Doukas, Michael P.

    1995-01-01

    Airborne sulfur dioxide (SO2) gas sampling of the Cook Inlet volcanoes (Mt. Spurr, Redoubt, Iliamna, and Augustine) began in 1986 when several measurements were carried out at Augustine volcano during the eruption of 1986 (Rose and others, 1988). More systematic monitoring for SO2 began in March 1990 and for carbon dioxide (CO2) began in June, 1990 at Redoubt Volcano (Brantley, 1990 and Casadevall and others, 1994) and continues to the present. This report contains all of the available daily SO2 and CO2 emission rates determined by the U.S. Geological Survey (USGS) from March 1990 through July 1994. Intermittent measurements (four to six month intervals) at Augustine and Iliamna began in 1990 and continues to the present. Intermittent measurements began at Mt. Spurr volcano in 1991, and were continued at more regular intervals from June, 1992 through the 1992 eruption at the Crater Peak vent to the present.

  19. International Workshop on Carbon Cycling and Coral Reef Metabolism; Sangosho no tanso junkan ni kansuru kokusai workshop hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-10-16

    The paper described the International Workshop on Carbon Cycling and Coral Reef Metabolism which was held at Miyako-jima, Okinawa Pref. on October 17-24, 1995. In the workshop, researchers got together which are involved in marine chemistry, marine biology, coral ecology, and environmental science, and discussed the carbon cycling and metabolism of coral reef. Discussions were made on what the coral reef ecosystem is, and what the definition of a sink or a source for CO2 is. Also discussed were scales of how much time and space should be considered to make these issues clear. Further, it was proposed that it was necessary to investigate carbon balance of both the whole system and the components of the system and to keep track of mass transfer among neighboring components of the system. Seventeen presentations were given. The workshop obtained a definite consensus on carbon balance of the coral reef system. 123 refs., 39 figs., 9 tabs.

  20. Bridging Political Expectations and Scientific Limitations in Climate Risk Management. On the Uncertain Effects of International Carbon Sink Policies

    Energy Technology Data Exchange (ETDEWEB)

    Loevbrand, E. [Environmental Science Section, Department of Biology and Environmental Science, Kalmar University, SE-391 82 Kalmar (Sweden)

    2004-12-01

    Despite great advances in carbon cycle research during the past decade the climatic impact of terrestrial ecosystems is still highly uncertain. Although contemporary studies suggest that the terrestrial biosphere has acted as a net sink to atmospheric carbon during the past two decades, the future role of terrestrial carbon pools is most difficult to foresee. When land use change and forestry activities were included into the Kyoto Protocol in 1997, the requirements for scientific precision increased significantly. At the same time the political expectations of carbon sequestration as climate mitigation strategy added uncertainties of a social kind to the study of land-atmosphere carbon exchange that have been difficult to address by conventional scientific methods. In this paper I explore how the failure to take into account the effects of direct human activity in scientific projections of future terrestrial carbon storage has resulted in a simplified appreciation of the risks embedded in a global carbon sequestration scheme. I argue that the social limits to scientific analysis must be addressed in order to accommodate these risks in future climate governance and to enable continued scientific authority in the international climate regime.

  1. Sulfur formation and recovery in a thiosulfate-oxidizing bioreactor.

    Science.gov (United States)

    González-Sánchez, A; Meulepas, R; Revah, S

    2008-08-01

    This work describes the design and performance of a thiosulfate-oxidizing bioreactor that allowed high elemental sulfur production and recovery efficiency. The reactor system, referred to as a Supernatant-Recycling Settler Bioreactor (SRSB), consisted of a cylindrical upflow reactor and a separate aeration vessel. The reactor was equipped with an internal settler and packing material (structured corrugated PVC sheets) to facilitate both cell retention and the settling of the formed elemental sulfur. The supernatant from the reactor was continuously recirculated through the aerator. An inlet thiosulfate concentration of 100 mmol l(-1) was used. The reactor system was fed with 89 mmol l(-1) d(-1) thiosulfate reaching 98 to 100% thiosulfate conversion with an elemental sulfur yield of 77%. Ninety-three percent of the produced sulfur was harvested from the bottom of the reactor as sulfur sludge. The dry sulfur sludge contained 87% elemental sulfur. The inclusion of an internal settler and packing material in the reactor system resulted in an effective retention of sulfur and biomass inside the bioreactor, preventing the oxidation of thiosulfate and elemental sulfur to sulfate in the aerator and, therefore, improving the efficiency of elemental sulfur formation and recovery.

  2. Overview of Carbon Dioxide Control Issues During International Space Station/Space Shuttle Joint Docked Operations

    Science.gov (United States)

    Matty, Christopher M.

    2010-01-01

    Crewed space vehicles have a common requirement to remove the carbon dioxide (CO2) created by the metabolic processes of the crew. The space shuttle [Space Transportation System (STS)] and International Space Station (ISS) each have systems in place that allow control and removal of CO2 from the habitable cabin environment. During periods in which the space shuttle is docked to the ISS, known as "joint docked operations," the space shuttle and ISS share a common atmosphere environment. During this period, an elevated amount of CO2 is produced through the combined metabolic activity of the STS and ISS crews. This elevated CO2 production, together with the large effective atmosphere created by collective volumes of the docked vehicles, creates a unique set of requirements for CO2 removal. This paper will describe individual CO2 control plans implemented by STS and ISS engineering teams, as well as the integrated plans used when both vehicles are docked. The paper will also discuss some of the issues and anomalies experienced by both engineering teams.

  3. Acting Globally: Potential Carbon Emissions Mitigation Impacts from an International Standards and Labelling Program

    Energy Technology Data Exchange (ETDEWEB)

    McNeil, Michael A; Letschert, Virginie E.; de la Rue du Can, Stephane; Egan, Christine

    2009-05-29

    This paper presents an analysis of the potential impacts of an international initiative designed to support and promote the development and implementation of appliances standards and labelling programs throughout the world. As part of previous research efforts, LBNL developed the Bottom Up Energy Analysis System (BUENAS), an analysis framework that estimates impact potentials of energy efficiency policies on a global scale. In this paper, we apply this framework to an initiative that would result in the successful implementation of programs focused on high priority regions and product types, thus evaluating the potential impacts of such an initiative in terms of electricity savings and carbon mitigation in 2030. In order to model the likely parameters of such a program, we limit impacts to a five year period starting in 2009, but assume that the first 5 years of a program will result in implementation of 'best practice' minimum efficiency performance standards by 2014. The 'high priority' regions considered are: Brazil, China, the European Union,India, Mexico and the United States. The products considered are: refrigerators, air conditioners, lighting (both fluorescent and incandescent), standby power (for consumer electronics) and televisions in the residential sector, and air conditioning and lighting in commercial buildings. In 2020, these regions and enduses account for about 37percent of global residential electricity and 29percent of electricity in commercial buildings. We find that 850Mt of CO2 could be saved in buildings by 2030 compared to the baseline forecast.

  4. Transporters in plant sulfur metabolism

    Directory of Open Access Journals (Sweden)

    Tamara eGigolashvili

    2014-09-01

    Full Text Available Sulfur is an essential nutrient, necessary for synthesis of many metabolites. The uptake of sulfate, primary and secondary assimilation, the biosynthesis, storage and final utilisation of sulfur (S containing compounds requires a lot of movement between organs, cells, and organelles. Efficient transport systems of S-containing compounds across the internal barriers or the plasma membrane and organellar membranes are therefore required. Here, we review a current state of knowledge of the transport of a range of S-containing metabolites within and between the cells as well as of their long distance transport. An improved understanding of mechanisms and regulation of transport will facilitate successful engineering of the respective pathways, to improve the plant yield, biotic interaction and nutritional properties of crops.

  5. Accumulation of atmospheric sulfur in some Costa Rican soils

    Science.gov (United States)

    Bern, Carleton R.; Townsend, Alan R.

    2013-01-01

    Sulfur is one of the macronutrient elements whose sources to terrestrial ecosystems should shift from dominance by rock-weathering to atmospheric deposition as soils and underlying substrate undergo progressive weathering and leaching. However, the nature and timing of this transition is not well known. We investigated sources of sulfur to tropical rain forests growing on basalt-derived soils in the Osa Peninsula region of Costa Rica. Sulfur sources were examined using stable isotope ratios (δ34S) and compared to chemical indices of soil development. The most weathered soils, and the forests they supported, are dominated by atmospheric sulfur, while a less weathered soil type contains both rock-derived and atmospheric sulfur. Patterns of increasing δ34S with increasing soil sulfur concentration across the landscape suggest atmospheric sulfur is accumulating, and little rock-derived sulfur has been retained. Soil sulfur, minus adsorbed sulfate, is correlated with carbon and nitrogen, implying that sulfur accumulation occurs as plants and microbes incorporate sulfur into organic matter. Only the lower depth increments of the more weathered soils contained significant adsorbed sulfate. The evidence suggests a pattern of soil development in which sulfur-bearing minerals in rock, such as sulfides, weather early relative to other minerals, and the released sulfate is leached away. Sulfur added via atmospheric deposition is retained as organic matter accumulates in the soil profile. Adsorbed sulfate accumulates later, driven by changes in soil chemistry and mineralogy. These aspects of sulfur behavior during pedogenesis in this environment may hasten the transition to dominance by atmospheric sources.

  6. 气相色谱法分析褐煤提质低温热解气中含硫化合物的研究%Study on sulfur compounds in low-temperature carbonization of brown coal by Gas Chromatography

    Institute of Scientific and Technical Information of China (English)

    崔新涛; 李香兰; 张永发; 孙亚玲

    2013-01-01

    Using TXS-Ⅱ sulfur analyzer quantitatively analyzed the sulfur compounds in low temperature carbonization gas. The result showed that the method of eliminating H2 S and COS of high concentration by desulfurizer and using TCP column to analyze the compositions of sulfur compounds by quantitative analysis, leads to a smaller measured value, because the desulfurizer will absorb some organic sulfur. Four different chromatographic columns were made to check their effects in desulfurization. After a series of exploration, a gas chromatography analysis method of simplicity and accuracy to determine the sulfur compounds in low temperature carbonization gas was established. Besides, the sulfur compounds in low temperature carbonization gas of different brown coal were analyzed by this method, providing a data base for desulfurization of pyrolysis gas.%采用TXS-Ⅱ硫分析仪对褐煤提质过程中的低温热解气进行含硫化合物定量分析研究,结果表明:(1)将气样通过脱硫剂脱除高浓度的H2S和COS之后再进行定量,因脱硫剂吸收有机含硫化合物,测定结果偏小;(2)制备了4种新的色谱分离柱,考查了这些色谱柱对有机含硫化合物的分离效果,最终建立了简便、准确检测低温热解气中含硫化合物的气相色谱分析方法,利用该方法分别对3种褐煤的低温热解过程中的气体进行了含硫化合物分析,为低温热解气的脱硫提供了依据.

  7. Dose rate effect on internal friction and structural transformations in electron-irradiated carbon-armored composites

    Energy Technology Data Exchange (ETDEWEB)

    Zaikin, Yu.A. [Al Farabi Kazakh National University, 96a Tole bi, 480012 Almaty (Kazakhstan)]. E-mail: DrZaykin@mail.ru; Aimuratov, D.B. [Al Farabi Kazakh National University, 96a Tole bi, 480012 Almaty (Kazakhstan); Al-Sheikhly, M. [University of Maryland, College Park (United States)

    2007-08-15

    Temperature dependence of internal friction and specific electric resistance of multi-layer carbon-armored epoxy-based composites is experimentally studied in the temperature range of 20-300 deg. C before and after irradiation with 2 MeV electrons. It is shown that carbon penetration into the polymer matrix causes intense polymer cross-linking in the basic layers of the composite even at low irradiation doses. The strong effect of dose rate on radiation-induced structural transformations was observed.

  8. A Praline-Like Flexible Interlayer with Highly Mounted Polysulfide Anchors for Lithium-Sulfur Batteries.

    Science.gov (United States)

    Zhao, Teng; Ye, Yusheng; Lao, Cheng-Yen; Divitini, Giorgio; Coxon, Paul R; Peng, Xiaoyu; He, Xiong; Kim, Hyun-Kyung; Xi, Kai; Ducati, Caterina; Chen, Renjie; Liu, Yingjun; Ramakrishna, Seeram; Kumar, Ramachandran Vasant

    2017-08-21

    The development of lithium-sulfur (Li-S) batteries is dogged by the rapid capacity decay arising from polysulfide dissolution and diffusion in organic electrolytes. To solve this critical issue, a praline-like flexible interlayer consisting of high-loading titanium oxide (TiO2 ) nanoparticles and relatively long carbon nanofibers is fabricated. TiO2 nanoparticles with a size gradient occupy both the external and internal of carbon fiber and serve as anchors that allow the chemical adsorption of polysulfides through a conductive nanoarchitecture. The porous conductive carbon backbone helps in the physical absorption of polysulfides and provides redox reaction sites to allow the polysulfides to be reused. More importantly, it offers enough mechanical strength to support a high load TiO2 nanoparticle (79 wt%) that maximizes their chemical role, and can accommodate the large volume changes. Significant enhancement in cycle stability and rate capability is achieved for a readily available sulfur/multi-walled carbon nanotube composite cathode simply by incorporating this hierarchically nanostructured interlayer. The design and synthesis of interlayers by in situ integration of metal oxides and carbon fibers via a simple route offers the potential to advance Li-S batteries for practical applications in the future. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. A lithium-ion sulfur battery based on a carbon-coated lithium-sulfide cathode and an electrodeposited silicon-based anode.

    Science.gov (United States)

    Agostini, Marco; Hassoun, Jusef; Liu, Jun; Jeong, Moongook; Nara, Hiroki; Momma, Toshiyuki; Osaka, Tetsuya; Sun, Yang-Kook; Scrosati, Bruno

    2014-07-23

    In this paper, we report a lithium-ion battery employing a lithium sulfide cathode and a silicon-based anode. The high capacity of the silicon anode and the high efficiency and cycling rate of the lithium sulfide cathode allowed optimal full cell balance. We show in fact that the battery operates with a very stable capacity of about 280 mAh g(-1) at an average voltage of 1.4 V. To the best of our knowledge, this battery is one of the rare examples of lithium-metal-free sulfur battery. Considering the high theoretical capacity of the employed electrodes, we believe that the battery here reported may be of potential interest as high-energy, safe, and low-cost power source for electric vehicles.

  10. High mass-loading of sulfur-based cathode composites and polysulfides stabilization for rechargeable lithium/sulfur batteries.

    Directory of Open Access Journals (Sweden)

    Toru eHara

    2015-05-01

    Full Text Available Although sulfur has a high theoretical gravimetric capacity, 1672 mAh/g, its insulating nature requires a large amount of conducting additives: this tends to result in a low mass-loading of active material (sulfur, and thereby, a lower capacity than expected. Therefore, an optimal choice of conducting agents and of the method for sulfur/conducting-agent integration is critically important. In this paper, we report that the areal capacity of 4.9 mAh/cm2 was achieved at a sulfur mass loading of 4.1 mg/cm2 by casting sulfur/polyacrylonitrile/ketjenblack (S/PAN/KB cathode composite into carbon fiber paper. This is the highest value among published/reported ones even though it does not contain expensive nano-sized carbon materials such as carbon nanotubes, graphene, or graphene-derivatives, and competitive enough with the conventional LiCoO2-based cathodes (e.g., LiCoO2, <20 mg/cm2 corresponding to <2.8 mAh/cm2. Furthermore, the combination of sulfur/PAN-based composite and PAN-based carbon fiber paper enabled the sulfur-based composite to be used even in carbonate-based electrolyte solution that many lithium/sulfur battery researchers avoid the use of it because of severer irreversible active material loss than in electrolyte solutions without carbonate-based solutions, and even at the highest mass-loading ever reported (the more sulfur is loaded, the more decomposed sulfides deposit at an anode surface..

  11. Fructose metabolism of the purple non-sulfur bacterium Rhodospirillum rubrum: effect of carbon dioxide on growth, and production of bacteriochlorophyll and organic acids.

    Science.gov (United States)

    Rudolf, Christiane; Grammel, Hartmut

    2012-04-05

    During fermentative metabolism, carbon dioxide fixation plays a key role in many bacteria regarding growth and production of organic acids. The present contribution, dealing with the facultative photosynthetic bacterium Rhodospirillum rubrum, reveals not only the strong influence of ambient carbon dioxide on the fermentative break-down of fructose but also a high impact on aerobic growth with fructose as sole carbon source. Both growth rates and biomass yield increased with increasing carbon dioxide supply in chemoheterotrophic aerobic cultures. Furthermore, intracellular metabolite concentration measurements showed almost negligible concentrations of the tricarboxylic acid cycle intermediates succinate, fumarate and malate under aerobic growth, in contrast to several metabolites of the glycolysis. In addition, we present a dual phase fed-batch process, where an aerobic growth phase is followed by an anaerobic production phase. The biosynthesis of bacteriochlorophyll and the secretion of organic acids were both affected by the carbon dioxide supply, the pH value and by the cell density at the time of switching from aerobic to anaerobic conditions. The formation of pigmented photosynthetic membranes and the amount of bacteriochlorophyll were inversely correlated to the secretion of succinate. Accounting the high biotechnological potential of R. rubrum, optimization of carbon dioxide supply is important because of the favored application of fructose-containing fermentable feedstock solutions in bio-industrial processes. Copyright © 2012 Elsevier Inc. All rights reserved.

  12. An international partnership approach to clean energy technology innovation: Carbon capture and storage

    Science.gov (United States)

    Yang, Xiaoliang

    Is a global research partnership effective in developing, deploying, and diffusing clean energy technologies? Drawing on and extending innovation system studies, this doctoral dissertation elaborates an analytical model for a global technology learning system; examines the rationales, mechanisms, and effectiveness of the United States-- China Clean Energy Research Center Advanced Coal Technology Consortium (CERC-ACTC); and analyzes government's role in developing and implementing carbon capture and storage technologies in the United States (U.S.) and China. Studies have shown that successful technology innovation leads to economic prosperity and national competence, and prove that technology innovation does not happen in isolation but rather within interactive systems among stakeholders. However, the innovation process itself remains unclear, particularly with regard to interactive learning among and between major institutional actors, including technology developers, regulators, and financial organizations. This study seeks to advance scholarship on the interactive learning from the angle of global interactive learning. This dissertation research project seeks, as well, to inform policy-makers of how to strengthen international collaboration in clean energy technology development. The U.S.--China CERC-ACTC announced by Presidents Obama and Hu in 2009, provided a unique opportunity to close this scholarly gap. ACTC aimed to "advance the coal technology needed to safely, effectively, and efficiently utilize coal resources including the ability to capture, store, and utilize the emissions from coal use in both nations " through the joint research and development by U.S. and Chinese scientists and engineers. This dissertation project included one-year field research in the two countries, with in-depth interviews of key stakeholders, a survey of Consortium participants, analysis of available data, and site visits to collaborative research projects from 2013-2014. This

  13. ADVANCED SULFUR CONTROL CONCEPTS

    Energy Technology Data Exchange (ETDEWEB)

    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).

  14. Renewable-surface sol-gel derived carbon ceramic electrode fabricated by [Ru(bpy)(tpy)Cl]PF6 and its application as an amperometric sensor for sulfide and sulfur oxoanions.

    Science.gov (United States)

    Salimi, Abdollah; Pourbeyram, Sima; Amini, Mohamad Kazem

    2002-12-01

    A highly sensitive and fast responding sensor for the determination of thiosulfate, sulfite, sulfide and dithionite is described. It consists of a chemically modified carbon ceramic composite electrode (CCE) containing [Ru(bpy)(tpy)Cl]PF6 complex that was constructed by the sol-gel technique. A reversible redox couple of Ru(II)/Ru(III) was observed as a solute in acetonitrile solution and as a component of carbon based conducting composite electrode. Electrochemical behavior and stability of modified CCE were investigated by cyclic voltametry, the apparent electron transfer rate constant (kappa(S)) and transfer coefficient (a) were determined by cyclic voltametry which were about 28 s(-1) and 0.43 respectively. Electrocatalytic oxidation of S(2-), SO3(2-), S2O4(2-) and S2O3(2-) were effective at the modified electrode at significantly reduced overpotentials and in the pH range 1-11. Optimum pH values for amperometric detection of thiosulfate, dithionite, sulfide and sulfite are 7, 9, 2 and 2. Under the optimized conditions the calibration curves are linear in the concentration ranges 1-500, 3-80, 2-90 and 1-100 microM for S2O3(2-), SO3(2-), S2- and S2O4(2-) determination. The detection limit (signal to noise is 3) and sensitivity are 0.5 and 12, 2.8 and 6, 1.6 and 8, and 0.65 microM and 80 nA microM(-1) for thiosulfate, sulfite, sulfide and dithionite detection. The modified carbon ceramic electrode doped with Ru-complex shows good reproducibility, a short response time (t 6 month) and especially good surface renewability by simple mechanical polishing (RSD for eight successive polishing is 2%). The advantages of this sulfur compound amperometric detector based on ruthenium doped CCE are high sensitivity, inherent stability at a broader pH range, excellent catalytic activity, less expense and simplicity of preparation in comparison with recently published papers. This sensor can be used as a chromatographic detector for analysis of sulfur derivatives.

  15. Internalization of carbon black and maghemite iron oxide nanoparticle mixtures leads to oxidant production.

    Science.gov (United States)

    Berg, J Michael; Ho, Shu; Hwang, Wonjoong; Zebda, Rema; Cummins, Kyle; Soriaga, Manuel P; Taylor, Robert; Guo, Bing; Sayes, Christie M

    2010-12-20

    The risk of potential human exposure to mixed nanomaterials in consumer, occupational, and medicinal settings is increasing as nanomaterials enter both the workplace and the marketplace. In this study, we investigated the toxicity of mixed engineered carbon black (ECB) and maghemite iron oxide (Fe(2)O(3)) nanoparticles in a cellular system to understand the mechanism of toxicity and potential methods of toxicity mitigation. Lung epithelial cells (A549) were exposed to mixed Fe(2)O(3) and ECB nanoparticles, mixed Fe(2)O(3) and ECB nanoparticles with the addition of L-ascorbic acid, and mixed Fe(2)O(3) and surface-oxidized engineered carbon black (ox-ECB) nanoparticles. The nanoparticles were characterized using transmission electron microscopy, nitrogen adsorption surface area measurement (BET), X-ray diffraction, and surface charge measurement. The carbon black nanoparticles were also characterized with a reductive capacity assay and by X-ray photoelectron spectroscopy (XPS). The cellular uptake of nanoparticles was analyzed via transmission electron microscopy and fluorescence microscopy; the cellular uptake of iron was quantified using inductively coupled plasma mass spectrometry (ICP-MS). Both the MTT assay and the ethidium homodimer and calcein AM live/dead assay were used to measure cellular proliferation and cytotoxicity, respectively. The dichlorofluorescein diacetate (DCFH-DA) assay was used to measure the intracellular generation of reactive oxygen species. Results show that both Fe(2)O(3) and ECB (or Fe(2)O(3) and ox-ECB) were co-internalized in intracellular vesicles. Additionally, after exposure to the mixture of nanoparticles, the amount of acidified lysosomes increased over time. The cellular uptake of Fe(2)O(3) nanoparticles was unaffected by mixing with ECB. Significant oxidant production occurred in cells exposed to mixed Fe(2)O(3) and ECB, but not in cells exposed to mixed Fe(2)O(3) and ox-ECB or in cells exposed to Fe(2)O(3) and ECB with the

  16. Automated Chemical Analysis of Internally Mixed Aerosol Particles Using X-ray Spectromicroscopy at the Carbon K-Edge

    Energy Technology Data Exchange (ETDEWEB)

    Gilles, Mary K; Moffet, R.C.; Henn, T.; Laskin, A.

    2011-01-20

    We have developed an automated data analysis method for atmospheric particles using scanning transmission X-ray microscopy coupled with near edge X-ray fine structure spectroscopy (STXM/NEXAFS). This method is applied to complex internally mixed submicrometer particles containing organic and inorganic material. Several algorithms were developed to exploit NEXAFS spectral features in the energy range from 278 to 320 eV for quantitative mapping of the spatial distribution of elemental carbon, organic carbon, potassium, and noncarbonaceous elements in particles of mixed composition. This energy range encompasses the carbon K-edge and potassium L2 and L3 edges. STXM/NEXAFS maps of different chemical components were complemented with a subsequent analysis using elemental maps obtained by scanning electron microscopy coupled with energy dispersive X-ray analysis (SEM/EDX). We demonstrate the application of the automated mapping algorithms for data analysis and the statistical classification of particles.

  17. Anthropogenic sulfur dioxide emissions: 1850–2005

    Directory of Open Access Journals (Sweden)

    S. J. Smith

    2011-02-01

    Full Text Available Sulfur aerosols impact human health, ecosystems, agriculture, and global and regional climate. A new annual estimate of anthropogenic global and regional sulfur dioxide emissions has been constructed spanning the period 1850–2005 using a bottom-up mass balance method, calibrated to country-level inventory data. Global emissions peaked in the early 1970s and decreased until 2000, with an increase in recent years due to increased emissions in China, international shipping, and developing countries in general. An uncertainty analysis was conducted including both random and systemic uncertainties. The overall global uncertainty in sulfur dioxide emissions is relatively small, but regional uncertainties ranged up to 30%. The largest contributors to uncertainty at present are emissions from China and international shipping. Emissions were distributed on a 0.5° grid by sector for use in coordinated climate model experiments.

  18. Sulfur recovery further improved

    Energy Technology Data Exchange (ETDEWEB)

    Borsboom, J.; Grinsven, M. van; Warners, A. van [Jacobs Nederland B.V., (Netherlands); Nisselrooy, P. van [Gastec N.V., (Netherlands)

    2002-04-01

    The original 100-year-old Claus process for producing sulfur from hydrogen sulfide in acid gas is described together with improvements which have been made over the years. The most recent modification, EUROCLAUS, achieves sulfur recoveries of 99-99.9 per cent. Five commercial units are being designed.

  19. Nanostructured sulfur cathodes

    KAUST Repository

    Yang, Yuan

    2013-01-01

    Rechargeable Li/S batteries have attracted significant attention lately due to their high specific energy and low cost. They are promising candidates for applications, including portable electronics, electric vehicles and grid-level energy storage. However, poor cycle life and low power capability are major technical obstacles. Various nanostructured sulfur cathodes have been developed to address these issues, as they provide greater resistance to pulverization, faster reaction kinetics and better trapping of soluble polysulfides. In this review, recent developments on nanostructured sulfur cathodes and mechanisms behind their operation are presented and discussed. Moreover, progress on novel characterization of sulfur cathodes is also summarized, as it has deepened the understanding of sulfur cathodes and will guide further rational design of sulfur electrodes. © 2013 The Royal Society of Chemistry.

  20. Balancing the carbon market. Analysing the international carbon market and abatement costs in 2020 for low-concentration targets

    Energy Technology Data Exchange (ETDEWEB)

    Den Elzen, M.G.J.; Mendoza-Beltran, M.A.; Piris-Cabezas, P.; Van Vuuren, D.P.

    2009-08-15

    This report describes our analysis of the impact of various policy choices and scientific uncertainties on the price of tradable emission units on the global carbon market in 2020 and the associated abatement costs. Our analysis was done under the assumption that the overall goal is to stabilise long-term greenhouse gas concentrations at 450 ppm CO2-eq. To meet these stabilisation targets on the long-term, Annex I countries as a group need to reduce by 25-40% below 1990 levels by 2020, and non-Annex I countries as a group need to keep emissions substantially below baseline (about 15 to 30%). The integrated modelling framework FAIR 2.2 is used for our analysis. The main findings of this study are: the degree of ambition for reductions of Annex I and non-Annex I countries is the most important policy choice influencing the price and abatement costs. Other less important policy choices include the ambition of US climate policy and the participation of the developing countries in the global carbon market. By allowing the use of forest-based options - including avoiding deforestation - for compliance in a well-designed carbon trading system, the global abatement costs could be reduced by between 25% and 65%. This would also make ambitious mitigation targets more feasible. In addition to the policy choices, important scientific uncertainties, in particular the baseline emissions (i.e. emissions in the absence of climate policy) and the assumed marginal abatement costs, strongly influence the carbon market.

  1. Geochemistry of sulfur in the Florida Everglades; 1994 through 1999

    Science.gov (United States)

    Bates, Anne L.; Orem, W.H.; Harvey, J.W.; Spiker, E. C.

    2000-01-01

    In this report, we present data on the geochemistry of sulfur in sediments and in surface water, groundwater, and rainwater in the Everglades region in south Florida. The results presented here are part of a larger study intended to determine the roles played by the cycling of carbon, nitrogen, phosphorus, and sulfur in the ecology of the south Florida wetlands. The geochemistry of sulfur in the region is particularly important because of its link to the production of toxic methylmercury through processes mediated by sulfate reducing bacteria. Sediment cores were collected from the Everglades Agricultural Area (EAA), Water Conservation Areas (WCAs) 1A and 2A, from Lake Okeechobee, and from Taylor Slough in the southern Everglades. Water collection was more widespread and includes surface water from WCAs 1A, 2A, 3A, 2B, the EAA, Taylor Slough, Lake Okeechobee, and the Kissimmee River. Groundwater was collected from The Everglades Nutrient Removal Area (ENR) and from WCA 2A. Rainwater was collected at two month intervals over a period of one year from the ENR and from WCA 2A. Water was analyzed for sulfate concentration and sulfate sulfur stable isotopic ratio (34S/32S). Sediment cores were analyzed for total sulfur concentration and/or for concentrations of sulfur species (sulfate, organic sulfur, disulfides, and acid volatile sulfides (AVS)) and for their stable sulfur isotopic ratio. Results show a decrease in total sulfur content (1.57 to 0.61 percent dry weight) with depth in two sediment cores collected in WCA 2A, indicating that there has been an increase in total sulfur content in recent times. A sediment core from the center of Lake Okeechobee shows a decrease in total sulfur content with depth (0.28 to 0.08 percent dry weight). A core from the periphery of the lake (South Bay) likewise shows a decrease in total sulfur content with depth (1.00 to 0.69 percent dry weight), however, the overall sulfur content is greater than that near the center at all depths

  2. Sulfur Confined in Sub-Nanometer-Sized 2 D Graphene Interlayers and Its Electrochemical Behavior in Lithium-Sulfur Batteries.

    Science.gov (United States)

    Du, Wen-Cheng; Zhang, Juan; Yin, Ya-Xia; Guo, Yu-Guo; Wan, Li-Jun

    2016-10-06

    Microspace-confined sulfur molecules as cathodes for lithium-sulfur (Li-S) batteries have shown great significance in both scientific and technical aspects. A study of different microspace-confined sulfur will not only promote the advancement of Li-S batteries but also arouse a wide interest in sulfur chemistry and related applications. Herein, we choose two-dimensional (2D) graphene interlayer as host and construct 2D space-confined sulfur model systems by simple intercalation chemistry of graphite oxide. Two routes, including solvothermal method and interlamellar reaction approach, are developed, and sulfur can be easily intercalated into sub-nanometer-sized graphene interlayers, forming a graphene confined sulfur structure. The 2D space-confined sulfur can work well in a carbonate-based electrolyte and show similar electrochemical behaviors of small sulfur molecules, indicating the special molecular form of sulfur in graphene layers. The 2D space-confined sulfur concept will be helpful for further understanding the electrochemical character of confined sulfur molecules and designing a high-performance sulfur cathode.

  3. Report from the International Permafrost Association: carbon pools in permafrost regions

    Science.gov (United States)

    Peter Kuhry; Chien-Lu Ping; Edward A.G. Schuur; Charles Tarnocai; Sergey. Zimov

    2009-01-01

    The IPA Carbon Pools in Permafrost Regions (CAPP) Project started in 2005, with endorsement of the Earth System Science Partnership (EESP) Global Carbon Project and the World Climate Research Programme (WCRP) Climate and Cryosphere Project. CAPP is also a project of the IPY. The project was launched because there is considerable concern and increased awareness both...

  4. Concentrations and Fractionation of Carbon, Iron, Sulfur, Nitrogen and Phosphorus in Mangrove Sediments Along an Intertidal Gradient (Semi-Arid Climate, New Caledonia

    Directory of Open Access Journals (Sweden)

    Jonathan Deborde

    2015-02-01

    Full Text Available In mangrove ecosystems, strong reciprocal interactions exist between plant and substrate. Under semi-arid climate, Rhizophora spp. are usually predominant, colonizing the seashore, and Avicennia marina develops at the edge of salt-flats, which is the highest zone in the intertidal range. Along this zonation, distribution and speciation of C, Fe, S, N, and P in sediments and pore-waters were investigated. From the land-side to the sea-side of the mangrove, sediments were characterized by I/ increase in: (i water content; (ii TOC; (iii mangrove-derived OM; II/ and decrease in: (i salinity; (ii redox; (iii pH; (iv solid Fe and solid P. Beneath Avicennia and Rhizophora, TS accumulated at depth, probably as a result of reduction of iron oxides and sulfate. The loss of total Fe observed towards the sea-side may be related to sulfur oxidation and to more intense tidal flushing of dissolved components. Except the organic forms, dissolved N and P concentrations were very low beneath Avicennia and Rhizophora stands, probably as a result of their uptake by the root systems. However, in the unvegetated salt-flat, NH4+ can accumulate in organic rich and anoxic layers. This study shows: (i the evolution of mangrove sediment biogeochemistry along the intertidal zone as a result of the different duration of tidal inundation and organic enrichment; and (ii the strong links between the distribution and speciation of the different elements.

  5. Systematic variation of the sodium/sulfur promoter content on carbon-supported iron catalysts for the Fischer-Tropsch to olefins reaction

    NARCIS (Netherlands)

    Oschatz, M.; Krans, N.A.; Xie, J.; de Jong, K.P.

    2016-01-01

    The Fischer–Tropsch to olefins (FTO) process is a method for the direct conversion of synthesis gas to lower C2–C4 olefins. Carbon-supported iron carbide nanoparticles are attractive catalysts for this reaction. The catalytic activity can be improved and undesired formation of alkanes can be suppres

  6. Systematic variation of the sodium/sulfur promoter content on carbon-supported iron catalysts for the Fischer-Tropsch to olefins reaction

    NARCIS (Netherlands)

    Oschatz, M.; Krans, N.A.|info:eu-repo/dai/nl/41128942X; Xie, J.; de Jong, K.P.|info:eu-repo/dai/nl/06885580X

    2016-01-01

    The Fischer–Tropsch to olefins (FTO) process is a method for the direct conversion of synthesis gas to lower C2–C4 olefins. Carbon-supported iron carbide nanoparticles are attractive catalysts for this reaction. The catalytic activity can be improved and undesired formation of alkanes can be

  7. Internal length parameter and buckling analysis of carbon nanotubes using modified couple stress theory and Timoshenko beam model

    Science.gov (United States)

    Khajueenejad, F.; Ghanbari, J.

    2015-10-01

    The internal length parameter of the modified couple stress theory for single walled carbon nanotubes (CNTs) is determined in this paper. Buckling of CNTs have been studied using Timoshenko beam model and modified couple stress theory. The governing equations for three different end conditions, simple-simple, clamped-clamped and clamped-free, are solved using variational methods and an exact solution is provided for the buckling load. The effects of the internal length parameter on the buckling load of various CNT length and diameters are studied. It is observed that the internal length parameter has larger influence on the higher modes of buckling and for shorter nanotubes. A method presented to obtain the internal length parameter of higher order theories. By correlating the obtained results with the more accurate molecular dynamics simulations, the internal length parameter has been calculated for zigzag and armchair nanotubes. It is observed that the internal length parameter has slight dependency on the size of the CNTs and an average value is provided.

  8. Integrated Ultra-Wideband Tracking and Carbon Dioxide Sensing System Design for International Space Station Applications

    Science.gov (United States)

    Ni, Jianjun (David); Hafermalz, David; Dusl, John; Barton, Rick; Wagner, Ray; Ngo, Phong

    2015-01-01

    A three-dimensional (3D) Ultra-Wideband (UWB) Time-of-Arrival (TOA) tracking system has been studied at NASA Johnson Space Center (JSC) to provide the tracking capability inside the International Space Station (ISS) modules for various applications. One of applications is to locate and report the location where crew experienced possible high level of carbon-dioxide (CO2) and felt upset. Recent findings indicate that frequent, short-term crew exposure to elevated CO2 levels combined with other physiological impacts of microgravity may lead to a number of detrimental effects, including loss of vision. To evaluate the risks associated with transient elevated CO2 levels and design effective countermeasures, doctors must have access to frequent CO2 measurements in the immediate vicinity of individual crew members along with simultaneous measurements of their location in the space environment. To achieve this goal, a small, low-power, wearable system that integrates an accurate CO2 sensor with an ultra-wideband (UWB) radio capable of real-time location estimation and data communication is proposed. This system would be worn by crew members or mounted on a free-flyer and would automatically gather and transmit sampled sensor data tagged with real-time, high-resolution location information. Under the current proposed effort, a breadboard prototype of such a system has been developed. Although the initial effort is targeted to CO2 monitoring, the concept is applicable to other types of sensors. For the initial effort, a micro-controller is leveraged to integrate a low-power CO2 sensor with a commercially available UWB radio system with ranging capability. In order to accurately locate those places in a multipath intensive environment like ISS modules, it requires a robust real-time location system (RTLS) which can provide the required accuracy and update rate. A 3D UWB TOA tracking system with two-way ranging has been proposed and studied. The designed system will be tested

  9. Carbon Nanotubes in Water: MD Simulations of Internal and External Flow, Self Organization

    Science.gov (United States)

    Jaffe, Richard L.; Halicioglu, Timur; Werder, Thomas; Walther, Jens; Koumoutsakos, Petros; Arnold, James (Technical Monitor)

    2001-01-01

    We have developed computational tools, based on particle codes, for molecular dynamics (MD) simulation of carbon nanotubes (CNT) in aqueous environments. The interaction of CNTs with water is envisioned as a prototype for the design of engineering nano-devices, such as artificial sterocillia and molecular biosensors. Large scale simulations involving thousands of water molecules are possible due to our efficient parallel MD code that takes long range electrostatic interactions into account. Since CNTs can be considered as rolled up sheets of graphite, we expect the CNT-water interaction to be similar to the interaction of graphite with water. However, there are fundamental differences between considering graphite and CNTs, since the curvature of CNTs affects their chemical activity and also since capillary effects play an important role for both dynamic and static behaviour of materials inside CNTs. In recent studies Gordillo and Marti described the hydrogen bond structure as well as time dependent properties of water confined in CNTs. We are presenting results from the development of force fields describing the interaction of CNTs and water based on ab-initio quantum mechanical calculations. Furthermore, our results include both water flows external to CNTs and the behaviour of water nanodroplets inside heated CNTs. In the first case (external flows) the hydrophobic behaviour of CNTs is quantified and we analyze structural properties of water in the vicinity of CNTs with diagnostics such as hydrogen bond distribution, water dipole orientation and radial distribution functions. The presence of water leads to attractive forces between CNTs as a result of their hydrophobicity. Through extensive simulations we quantify these attractive forces in terms of the number and separation of the CNT. Results of our simulations involving arrays of CNTs indicate that these exhibit a hydrophobic behaviour that leads to self-organising structures capable of trapping water clusters

  10. Preparation and Electrochemical Properties of Sulfur/Ordered Mesoporous Carbon Composite%硫/有序介孔碳复合材料的制备及其电化学性能

    Institute of Scientific and Technical Information of China (English)

    李永; 董晓雯; 赵宏滨; 徐甲强

    2011-01-01

    An ordered mesoporous carbon (OMC) material was synthesized via a template synthesis method. The composites of S/OMC with OMC as a matrix of sulfur were prepared by means of low temperature melting. The composites were investigated by transmission electron microscopy, Brunauer-Emmett-Teller method and X-ray powder diffraction. The results show that the channels of OMC is in an order, and the specific surface area of OMC is >1 600 m2/g. The sulfur could be efficiently dispersed in OMC. The composites of S/OMC were determined by galvanostafic charge/discharge, cyclic voltammograms and electrochemical impedance spectroscopy. It is indicated that the S/OMC has preferable electrochemical reversible, and the first discharge capacity reaches 1430 mA.h/g and stabilizes at 500 mA.h/g after 60 cycles. It is essential for the improvement of the battery performance to possess the massive micropores with the greater surface area existed in the OMC.%用模板法合成有序介孔碳材料(ordered mesoporous carbon,OMC),以该材料作为硫的载体,用低温熔融的方法制备了硫/有序介孔碳(S/OMC)复合材料.通过透射电子显微镜、比表面分析和X射线粉末衍射仪对材料进行表征.结果表明:OMC孔道有序,比表面积高达1 600m2/g,硫在OMC内分散性良好.对S/OMC又进行了恒流充放电、循环伏安和交流阻抗等电化学性能测试,显示S/OMC电化学可逆性较好,首次放电容量达1 430mA·h/g,60次循环时仍稳定在500mA·h/g.OMC内部有序的孔道和较大的表面微孔对电池性能的提高起到了重要的作用.

  11. A long-life lithium ion sulfur battery exploiting high performance electrodes.

    Science.gov (United States)

    Moreno, Noelia; Agostini, Marco; Caballero, Alvaro; Morales, Julián; Hassoun, Jusef

    2015-10-04

    A novel lithium ion sulfur battery is formed by coupling an activated ordered mesoporous carbon-sulfur (AOMC-S) cathode and a nanostructured tin-carbon anode. The lithium ion cell has improved reversibility, high energy content and excellent cycle life.

  12. Sulfuric Acid on Europa

    Science.gov (United States)

    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.

  13. Cytoplasmic sulfur trafficking in sulfur-oxidizing prokaryotes.

    Science.gov (United States)

    Dahl, Christiane

    2015-04-01

    Persulfide groups are chemically versatile and participate in a wide array of biochemical pathways. Although it is well documented that persulfurated proteins supply a number of important and elaborate biosynthetic pathways with sulfane sulfur, it is far less acknowledged that the enzymatic generation of persulfidic sulfur, the successive transfer of sulfur as a persulfide between multiple proteins, and the oxidation of sulfane sulfur in protein-bound form are also essential steps during dissimilatory sulfur oxidation in bacteria and archaea. Here, the currently available information on sulfur trafficking in sulfur oxidizing prokaryotes is reviewed, and the idea is discussed that sulfur is always presented to cytoplasmic oxidizing enzymes in a protein-bound form, thus preventing the occurrence of free sulfide inside of the prokaryotic cell. Thus, sulfur trafficking emerges as a central element in sulfur-oxidizing pathways, and TusA homologous proteins appear to be central and common elements in these processes.

  14. Microbial processes of the carbon and sulfur cycles in an ice-covered, iron-rich meromictic lake Svetloe (Arkhangelsk region, Russia).

    Science.gov (United States)

    Savvichev, Alexander S; Kokryatskaya, Natalia M; Zabelina, Svetlana A; Rusanov, Igor I; Zakharova, Elena E; Veslopolova, Elena F; Lunina, Olga N; Patutina, Ekaterina O; Bumazhkin, Boris K; Gruzdev, Denis S; Sigalevich, Pavel A; Pimenov, Nikolay V; Kuznetsov, Boris B; Gorlenko, Vladimir M

    2017-02-01

    Biogeochemical, isotope geochemical and microbiological investigation of Lake Svetloe (White Sea basin), a meromictic freshwater was carried out in April 2014, when ice thickness was ∼0.5 m, and the ice-covered water column contained oxygen to 23 m depth. Below, the anoxic water column contained ferrous iron (up to 240 μμM), manganese (60 μM), sulfide (up to 2 μM) and dissolved methane (960 μM). The highest abundance of microbial cells revealed by epifluorescence microscopy was found in the chemocline (redox zone) at 23-24.5 m. Oxygenic photosynthesis exhibited two peaks: the major one (0.43 μmol C L(-1)  day(-1) ) below the ice and the minor one in the chemocline zone, where cyanobacteria related to Synechococcus rubescens were detected. The maximum of anoxygenic photosynthesis (0.69 μmol C L(-1)  day(-1) ) at the oxic/anoxic interface, for which green sulfur bacteria Chlorobium phaeoclathratiforme were probably responsible, exceeded the value for oxygenic photosynthesis. Bacterial sulfate reduction peaked (1.5 μmol S L(-1)  day(-1) ) below the chemocline zone. The rates of methane oxidation were as high as 1.8 μmol CH4  L(-1)  day(-1) at the oxi/anoxic interface and much lower in the oxic zone. Small phycoerythrin-containing Synechococcus-related cyanobacteria were probably involved in accumulation of metal oxides in the redox zone. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

  15. A facies model for internalites (internal wave deposits) on a gently sloping carbonate ramp (Upper Jurassic, Ricla, NE Spain)

    Science.gov (United States)

    Bádenas, Beatriz; Pomar, Luis; Aurell, Marc; Morsilli, Michele

    2012-10-01

    Internal waves are waves that propagate along the pycnocline, the interface between two density-stratified fluids. Even though internal waves are ubiquitous in oceans and lakes, their impact in the sedimentary record has remained largely unrecognized. Internal waves can remobilize the sediment from the depth at which the internal waves break onto the sea floor. In shelf, or ramp settings, internal wave deposits (internalites) have to be distinguished from tempestites while in slope and deeper settings internalites require distinction from turbidites. The Upper Kimmeridgian carbonate ramp succession cropping out near Ricla (NE Spain) provides some key evidence to differentiate the depositional processes induced by breaking internal waves from those related to surface storm waves. Sandy-oolitic grainstone eventites, previously interpreted as tempestites, contain evidence of reworking by turbulent events related to breaking internal waves. Underlying rationale are: 1) they occur in distal mid-ramp position, detached from the coeval shallow-water successions; 2) they do not have the characteristic coarsening- and thickening upward trend of storm deposits; 3) they gradually thin-out to disappear both up dip and down dip, interbedded with mid-ramp lime mudstones; and 4) they show little or no erosion towards the shallower areas. A facies model for internalites produced by two sediment populations, sand and mud, on a gently sloping carbonate ramp is proposed. The individual internalites occurring at Ricla include several architectural elements, sequentially organized in dip direction, which can be related to the flows associated with breaking internal waves: erosion in the breaker zone, swash run-up and tractive backwash flow. Individual internalites stack, with down- and up-slope shingling configuration, in dm-thick packages thought to reflect the up-slope and down-slope migration of the breaker zone, in turn related to depth variations of the palaeo-pycnocline. Packages

  16. Efficient Fabrication of Hierarchically Porous Graphene-Derived Aerogel and Its Application in Lithium Sulfur Battery.

    Science.gov (United States)

    Zhang, Kai; Qin, Furong; Lai, Yanqing; Li, Jie; Lei, Xiaoke; Wang, Mengran; Lu, Hai; Fang, Jing

    2016-03-09

    Hierarchically porous carbon/graphene aerogel (CGA) with relatively high surface area and pore volume is synthesized through an efficient fabrication strategy, which involves forming hydrothermal carbon layer on the pore wall as upholder and directly carbonizing the wet hydrogel from hydrothermal reaction, without using any special drying techniques. Cassava powder is used as carbon precursor which enables sustainable synthesis. Carbonizing the wet hydrothermal product is found to be a self-activation process, through which abundant pores are generated. The aerogel is used as host to encapsulate sulfur for lithium sulfur battery. Graphene, served as highly conductive scaffold, accelerates the transport of the electrons. The hierarchically porous structure is in favor of improving the electrochemical performance of lithium sulfur battery. Therefore, the cathode with high sulfur loading and high sulfur content can deliver very good performance.

  17. Carbon to electricity in a solid oxide fuel cell combined with an internal catalytic gasification process

    Institute of Scientific and Technical Information of China (English)

    M. Konsolakis; G. E. Marnellos; A. Al-Musa; N. Kaklidis; I. Garagounis; V. Kyriakou

    2015-01-01

    This study explores strategies to develop highly efficient direct carbon fuel cells (DCFCs) by com‐bining a solid‐oxide fuel cell (SOFC) with a catalyst‐aided carbon‐gasification process. This system employs Cu/CeO2 composites as both anodic electrodes and carbon additives in a cell of the type:carbon|Cu‐CeO2/YSZ/Ag|air. The study investigates the impact on in situ carbon‐gasification and DCFC performance characteristics of catalyst addition and variation in the carrier gas used (inert He versus reactive CO2). The results indicate that cell performance is significantly improved by infusing the catalyst into the carbon feedstock and by employing CO2 as the carrier gas. At 800 °C, the maxi‐mum power output is enhanced by approximately 40% and 230% for carbon/CO2 and car‐bon/catalyst/CO2 systems, respectively, compared with that of the carbon/He configuration. The increase observed when employing the catalyst and CO2 as the carrier gas can be primarily at‐tributed to the pronounced effect of the catalyst on carbon‐gasification through the re‐verse‐Boudouard reaction, and the subsequent in situ electro‐oxidation of CO at the anode three‐phase boundary.

  18. Experimental Study on Mercury Removal of High-Sulfur Petroleum Coke Activated Carbon Impregnated With Bromine%载溴高硫石油焦活性炭脱汞实验研究

    Institute of Scientific and Technical Information of China (English)

    洪亚光; 段钰锋; 朱纯; 周强; 佘敏; 韦红旗

    2014-01-01

    As a petrochemical industry by-product, petroleum coke with high sulfur content was made into activated carbon, and then treated by NH4Br solution for modification with Br uploading on its surface. The prepared petroleum cokes were characterized by means of nitrogen (N2) adsorption/desorption, and scanning electron microscopy/X-ray energy dispersive spectroscope (SEM-EDS). Experimental studies on Hg removal were investigated in both a fixed bed and an entrained flow reactor system. Petroleum coke activated carbon modified by NH4Br performs better mercury adsorption capacity than commonly used activated carbon from coal. It is noted that 1% additive of NH4Br into the petroleum coke activated carbon nearly remove all the mercury in a fixed bed within 120 min, and the mercury removal efficiency of entrained flow reactor system under condition of 120℃, 2 second residence time and about 90 000 C/Hg ratio is above 90%. The results solidly support that the modified high sulfur petroleum coke can be used as high effective mercury removal adsorbent in a flue gas injection of demercuration system for coal fired power plant.%以石化工业副产物高硫石油焦制备的活性炭为脱汞吸附剂,对其进行NH4Br溶液浸渍改性成为载溴富硫活性炭。采用N2吸附/脱附、扫描电子显微镜/X射线能谱仪(scanning electron microscopy/X-ray energy dispersive spectroscope, SEM/EDS)等方法对吸附剂进行孔隙结构和微观形貌表征。分别在固定床反应器和管道喷射实验装置上进行汞吸附脱除实验研究。与煤制活性炭相比,高硫石油焦活性炭具有更高的汞吸附能力,经过质量分数为1%的NH4Br溶液改性后,石油焦活性炭固定床120 min 内汞脱除率接近100%;在120℃、2 s 停留时间、碳汞比约为90000条件下,喷射脱汞效率亦超过90%。实验结果表明,溴化铵改性高硫石油焦活性炭可作为燃煤电厂烟气喷射脱汞的高效吸附剂。

  19. Carbon Emission Mitigation Potentials of Different Policy Scenarios and Their Effects on International Aviation in the Korean Context

    Directory of Open Access Journals (Sweden)

    Sungwook Yoon

    2016-11-01

    Full Text Available The objective of this study is to seek better policy options for greenhouse gas (GHG emission reduction in Korea’s international aviation industry by analyzing economic efficiency and environmental effectiveness with a system dynamics (SD model. Accordingly, we measured airlines sales and CO2 emission reductions to evaluate economic efficiency and environmental effectiveness, respectively, for various policies. The results show that the average carbon emission reduction rates of four policies compared to the business-as-usual (BAU scenario between 2015 and 2030 are 4.00% (Voluntary Agreement, 7.25% (Emission Trading System or ETS-30,000, 8.33% (Carbon Tax or CT-37,500, and 8.48% (Emission Charge System or EC-30,000. The average rate of decrease in airline sales compared to BAU for the ETS policy is 0.1% at 2030. Our results show that the ETS approach is the most efficient of all the analyzed CO2 reduction policies in economic terms, while the EC approach is the best policy to reduce GHG emissions. This study provides a foundation for devising effective response measures pertaining to GHG reduction and supports decision making on carbon tax and carbon credit pricing.

  20. Photocatalytic splitting of CS2 to S8 and a carbon-sulfur polymer catalyzed by a bimetallic ruthenium(II) compound with a tertiary amine binding site: toward photocatalytic splitting of CO2?

    Science.gov (United States)

    Livanov, Konstantin; Madhu, Vedichi; Balaraman, Ekambaram; Shimon, Linda J W; Diskin-Posner, Yael; Neumann, Ronny

    2011-11-21

    The catalytic photocleavage of CS(2) to S(8) and a (C(x)S(y))(n) polymer with visible light using a dinuclear ruthenium(II) compound with a bipyridine units for photoactivity and a vicinal tertiary amine binding site for CS(2) activation was studied. The catalyst was characterized by X-ray diffraction, (1)H NMR, and (13)C NMR, ESI-MS and elemental analysis. CS(2) photocleavage was significant (240 turnovers, 20 h) to yield isolable S(8) and a (C(x)S(y))(n) polymer. A mononuclear catalyst or one without an amine binding site showed significantly less activity. XPS of the (C(x)S(y))(n) polymer showed a carbon/sulfur ratio ∼1.5-1.6 indicating that in part both C-S bonds of CS(2) had been cleaved. Catalyst was also included within the polymer. The absence of peaks in the (1)H NMR verified the (C(x)S(y))(n) nature of the polymer, while (13)C NMR and IR indicated that the polymer had multiple types of C-S and C-C bonds.

  1. Solid-State Lithium-Sulfur Batteries Operated at 37 °C with Composites of Nanostructured Li7La3Zr2O12/Carbon Foam and Polymer.

    Science.gov (United States)

    Tao, Xinyong; Liu, Yayuan; Liu, Wei; Zhou, Guangmin; Zhao, Jie; Lin, Dingchang; Zu, Chenxi; Sheng, Ouwei; Zhang, Wenkui; Lee, Hyun-Wook; Cui, Yi

    2017-05-10

    An all solid-state lithium-ion battery with high energy density and high safety is a promising solution for a next-generation energy storage system. High interface resistance of the electrodes and poor ion conductivity of solid-state electrolytes are two main challenges for solid-state batteries, which require operation at elevated temperatures of 60-90 °C. Herein, we report the facile synthesis of Al(3+)/Nb(5+) codoped cubic Li7La3Zr2O12 (LLZO) nanoparticles and LLZO nanoparticle-decorated porous carbon foam (LLZO@C) by the one-step Pechini sol-gel method. The LLZO nanoparticle-filled poly(ethylene oxide) electrolyte shows improved conductivity compared with filler-free samples. The sulfur composite cathode based on LLZO@C can deliver an attractive specific capacity of >900 mAh g(-1) at the human body temperature 37 °C and a high capacity of 1210 and 1556 mAh g(-1) at 50 and 70 °C, respectively. In addition, the solid-state Li-S batteries exhibit high Coulombic efficiency and show remarkably stable cycling performance.

  2. Metal-sulfur type cell having improved positive electrode

    Science.gov (United States)

    Dejonghe, Lutgard C.; Visco, Steven J.; Mailhe, Catherine C.; Armand, Michel B.

    1988-03-01

    A novel metal-sulfur type cell operable at a temperature of 200 C or less with an energy density of 150 Whrs/Kg or better is disclosed characterized by an organo-sulfur cathode formed from an organic-sulfur compound having the general formula, in its charged state, of (R(S) sub y) n wherein y = 1 to 6; n = 2 to 20; and R is one or more different aliphatic or aromatic organic moieties having 1 to 20 carbon atoms, which may include one or more oxygen, sulfur, or nitrogen heteroatoms when R comprises one or more aromatic rings, or one or more oxygen, sulfur, nitrogen, or fluorine atoms associated with the chain when R comprises an aliphatic chain, wherein the aliphatic group may be linear or branched, saturated or unsaturated, and wherein either the aliphatic chain or the aromatic ring may have substituted groups thereon.

  3. K- and L-edge X-ray absorption spectrum calculations of closed-shell carbon, silicon, germanium, and sulfur compounds using damped four-component density functional response theory.

    Science.gov (United States)

    Fransson, Thomas; Burdakova, Daria; Norman, Patrick

    2016-05-21

    X-ray absorption spectra of carbon, silicon, germanium, and sulfur compounds have been investigated by means of damped four-component density functional response theory. It is demonstrated that a reliable description of relativistic effects is obtained at both K- and L-edges. Notably, an excellent agreement with experimental results is obtained for L2,3-spectra-with spin-orbit effects well accounted for-also in cases when the experimental intensity ratio deviates from the statistical one of 2 : 1. The theoretical results are consistent with calculations using standard response theory as well as recently reported real-time propagation methods in time-dependent density functional theory, and the virtues of different approaches are discussed. As compared to silane and silicon tetrachloride, an anomalous error in the absolute energy is reported for the L2,3-spectrum of silicon tetrafluoride, amounting to an additional spectral shift of ∼1 eV. This anomaly is also observed for other exchange-correlation functionals, but it is seen neither at other silicon edges nor at the carbon K-edge of fluorine derivatives of ethene. Considering the series of molecules SiH4-XFX with X = 1, 2, 3, 4, a gradual divergence from interpolated experimental ionization potentials is observed at the level of Kohn-Sham density functional theory (DFT), and to a smaller extent with the use of Hartree-Fock. This anomalous error is thus attributed partly to difficulties in correctly emulating the electronic structure effects imposed by the very electronegative fluorines, and partly due to inconsistencies in the spurious electron self-repulsion in DFT. Substitution with one, or possibly two, fluorine atoms is estimated to yield small enough errors to allow for reliable interpretations and predictions of L2,3-spectra of more complex and extended silicon-based systems.

  4. Attribution of atmospheric sulfur dioxide over the English Channel to dimethyl sulfide and changing ship emissions

    Science.gov (United States)

    Yang, Mingxi; Bell, Thomas G.; Hopkins, Frances E.; Smyth, Timothy J.

    2016-04-01

    Atmospheric sulfur dioxide (SO2) was measured continuously from the Penlee Point Atmospheric Observatory (PPAO) near Plymouth, United Kingdom, between May 2014 and November 2015. This coastal site is exposed to marine air across a wide wind sector. The predominant southwesterly winds carry relatively clean background Atlantic air. In contrast, air from the southeast is heavily influenced by exhaust plumes from ships in the English Channel as well as near Plymouth Sound. A new International Maritime Organization (IMO) regulation came into force in January 2015 to reduce the maximum allowed sulfur content in ships' fuel 10-fold in sulfur emission control areas such as the English Channel. Our observations suggest a 3-fold reduction in ship-emitted SO2 from 2014 to 2015. Apparent fuel sulfur content calculated from coincidental SO2 and carbon dioxide (CO2) peaks from local ship plumes show a high level of compliance to the IMO regulation (> 95 %) in both years (˜ 70 % of ships in 2014 were already emitting at levels below the 2015 cap). Dimethyl sulfide (DMS) is an important source of atmospheric SO2 even in this semi-polluted region. The relative contribution of DMS oxidation to the SO2 burden over the English Channel increased from about one-third in 2014 to about one-half in 2015 due to the reduction in ship sulfur emissions. Our diel analysis suggests that SO2 is removed from the marine atmospheric boundary layer in about half a day, with dry deposition to the ocean accounting for a quarter of the total loss.

  5. Some thoughts on GAIA and the sulfur cycle

    Science.gov (United States)

    Lovelock, J. E.

    1985-01-01

    The data hypothesis states that the composition, oxidation reduction state, and temperature of the troposphere are actively regulated by the biota for the biota. One of the early predictions of the Gaia hypothesis was that there should be a sulfur compound made by the biota in the oceans. It would need to be stable enough against oxidation in water to allow its transfer to the air. Either the sulfur compound itself or its atmospheric oxidation product would have to return sulfur from the sea to the land surfaces. The most likely candidate for this role was dimethyl sulfide. Another sulfur compound of interest from a Gaian viewpoint CS2 (carbon disulfide) is discussed. Theories on the production of dimethyl sulfide and carbon disulfide related to the Gaian hypothesis are examined.

  6. The production of sulfur targets for gamma-ray spectroscopy

    CERN Document Server

    Greene, J P

    2002-01-01

    The production of thin sulfur targets for nuclear physics, either in elemental or in compound form, is problematic, due to low melting points, high vapor pressures and high dissociation rates. Many sulfur compounds have been tried in the past without great success. In this paper, we report the use of spray coating molybdenum disulfide onto a thin carbon backing. The targets were of thickness 750 mu g/cm sup 2 (approx 300 mu g/cm sup 2 of sulfur) on 15 mu g/cm sup 2 carbon backings, and withstood 4 pnA (approx 10 mW/cm sup 2) of deposited beam power for several days without apparent loss of sulfur content.

  7. The role of sulfur trapped in micropores in the catalytic partial oxidation of hydrogen sulfide with oxygen

    NARCIS (Netherlands)

    Steijns, M.; Mars, P.

    1974-01-01

    The catalytic oxidation of hydrogen sulfide into sulfur with molecular oxygen has been studied in the temperature range 130–200 °C. Active carbon, molecular sieve 13X and liquid sulfur were used as catalysts. Sulfur is adsorbed in the micropores (3 < r < 40 Å) of the catalysts. Experiments with a su

  8. Assessment of Technology Readiness Level of a Carbon Dioxide Reduction Assembly (CRA) for use on International Space Station

    Science.gov (United States)

    Murdoch, Karen; Smith, Fred; Perry, Jay; Green, Steve

    2004-01-01

    When technologies are traded for incorporation into vehicle systems to support a specific mission scenario, they are often assessed in terms of Technology Readiness Level (TRL). TRL is based on three major categories of Core Technology Components, Ancillary Hardware and System Maturity, and Control and Control Integration. This paper describes the Technology Readiness Level assessment of the Carbon Dioxide Reduction Assembly (CRA) for use on the International Space Station. A team comprising of the NASA Johnson Space Center, Marshall Space Flight Center, Southwest Research Institute and Hamilton Sundstrand Space Systems International have been working on various aspects of the CRA to bring its TRL from 4/5 up to 6. This paper describes the work currently being done in the three major categories. Specific details are given on technology development of the Core Technology Components including the reactor, phase separator and CO2 compressor.

  9. Effect of aggregation, morphology and mixing state on optical properties of bare and internally mixed Black Carbon particles

    Science.gov (United States)

    Scarnato, Barbara; China, Swarup; Mazzoleni, Claudio

    2014-05-01

    Black carbon (BC) is a small, dark particle that warms Earth's climate. BC is a distinct type of carbonaceous aerosol particle, product of combustion of fossil and biomass fuels. Upon emission into the atmosphere, BC internally mixes with other aerosol compounds. According to recent studies, internal mixing of BC with other aerosol materials in the atmosphere alters its aggregate shape, absorption of solar radiation, and radiative forcing. These mixing state effects are not yet fully understood. Laboratory and field studies have identified a strong variability in the observed absorption efficiencies of internally mixed BC. Additionally, there is a discrepancy between modeled and measured values using traditional modeling approaches. This talk will investigate the central role of parameterization of light interaction by BC particles in the assessment of its radiative forcing and present a sensitivity study of the effect of aggregation, morphology and mixing state on optical properties of bare and internally mixed BC with mineral dust, ammonium sulfate, sodium chloride and others. Optical properties of the different mixtures, sampled both in field campaigns and laboratory environment, are computed using Discrete Dipole Approximation model in accordance with BC aggregation, morphology and mixing observed at microscopes. The results of this work are relevant for several applications in atmospheric science, including but not limited to radiative transfer calculations, regional and global climate modeling and, the interpretation of remote sensing measurements.

  10. 国内外碳排放管理标准化进展%The Progress of International and National Carbon Emission Management Standardization

    Institute of Scientific and Technical Information of China (English)

    陈亮; 陈健华; 鲍威; 孙亮; 郭慧婷

    2014-01-01

    Standardization, as a very effective tool, plays a more and more important supporting role in promoting China's policy implementation in addressing climate change and other issues. This paper summarizes the international situation and progress, and analyzes the international development tendency of carbon emission management standardization. Correspondingly, the national situation and progress of carbon emission management standardization is reviewed including involvement of international standardization, establishment of national standardization committee, development of national standards and so on. And the policy suggestions are raised to strengthen the standardization work in the fields of addressing climate change during the 12th Five-Year Plan period.

  11. Sulfur Poisoning of SOFC Anodes: Effect of Overpotential on Long-Term Degradation

    DEFF Research Database (Denmark)

    Hauch, Anne; Hagen, Anke; Hjelm, Johan

    2014-01-01

    Sulfur impurities in carbon containing fuels for solid oxide fuel cells (SOFC), e.g. natural gas and biogas, typically lead to significant losses in performance due to the sulfur sensitivity of Ni/yttria-stabilized-zirconia (YSZ) anodes for SOFC. Full cells having Ni/YSZ anodes have been characte......Sulfur impurities in carbon containing fuels for solid oxide fuel cells (SOFC), e.g. natural gas and biogas, typically lead to significant losses in performance due to the sulfur sensitivity of Ni/yttria-stabilized-zirconia (YSZ) anodes for SOFC. Full cells having Ni/YSZ anodes have been...

  12. Thermocatalytic process for CO.sub.2-free production of hydrogen and carbon from hydrocarbons

    Science.gov (United States)

    Muradov, Nazim Z.

    2011-08-23

    A novel process and apparatus are disclosed for sustainable CO.sub.2-free production of hydrogen and carbon by thermocatalytic decomposition (dissociation, pyrolysis, cracking) of hydrocarbon fuels over carbon-based catalysts in the absence of air and/or water. The apparatus and thermocatalytic process improve the activity and stability of carbon catalysts during the thermocatalytic process and produce both high purity hydrogen (at least, 99.0 volume %) and carbon, from any hydrocarbon fuel, including sulfurous fuels. In a preferred embodiment, production of hydrogen and carbon is achieved by both internal and external activation of carbon catalysts. Internal activation of carbon catalyst is accomplished by recycling of hydrogen-depleted gas containing unsaturated and aromatic hydrocarbons back to the reactor. External activation of the catalyst can be achieved via surface gasification with hot combustion gases during catalyst heating. The process and apparatus can be conveniently integrated with any type of fuel cell to generate electricity.

  13. Selective Sulfidation of Lead Smelter Slag with Sulfur

    Science.gov (United States)

    Han, Junwei; Liu, Wei; Wang, Dawei; Jiao, Fen; Qin, Wenqing

    2016-02-01

    The selective sulfidation of lead smelter slag with sulfur was studied. The effects of temperature, sulfur dosage, carbon, and Na salts additions were investigated based on thermodynamic calculation. The results indicated that more than 96 pct of zinc in the slag could be converted into sulfides. Increasing temperature, sulfur dosage, or Na salts dosage was conducive to the sulfidation of the zinc oxides in the slag. High temperature and excess Na salts would result in the more consumption of carbon and sulfur. Carbon addition not only promoted the selective sulfidation but reduced the sulfur dosage and eliminated the generation of SO2. Iron oxides had a buffering role on the sulfur efficient utilization. The transformation of sphalerite to wurtzite was feasible under reducing condition at high temperature, especially above 1273 K (1000 °C). The growth of ZnS particles largely depended upon the roasting temperature. They were significantly increased when the temperature was above 1273 K (1000 °C), which was attributed to the formation of a liquid phase.

  14. 载硫活性炭脱除天然气中单质汞的研究%Remove elemental mercury by sulfur-impregnated activated carbon in natural gas

    Institute of Scientific and Technical Information of China (English)

    吕维阳; 刘盛余; 能子礼超; 汪雪婷; 吴萧

    2016-01-01

    在固定床反应装置上考察了商业载硫活性炭脱除天然气中气态 Hg0的吸附性能、影响因素、再生方法以及吸附动力学,同时结合BET,FTIR,XRD等表征手段提出载硫活性炭脱汞机理.结果表明,空速对脱汞效率限制作用有限,空速从12000h-1提高至48000h-1,脱除率变化范围在 7%以内.增加汞浓度在初始阶段可以提高其脱汞率,增加单位质量活性炭对汞的吸附量,提高温度会增加吸附体系内的活化分子,提高脱汞率,温度在80℃时效果最优,但是温度过高则会产生负面效应.不同阶段的动力学拟合结果表明化学吸附是整个吸附过程的控制步骤.热脱附实验表明载硫活性炭的脱汞温度是在 300~450℃,再生后对汞的吸附能力减弱,其原因可归为再生过程中碳硫键的损失和活性炭二次碳化时表面的烧蚀.%The adsorption performance, influence factors, regeneration method and the adsorption dynamics of the gaseous Hg0 in natural gas removed by commercial sulfur-loaded activated carbon were studied on fixed reacting device. Meanwhile, the removal mercury mechanism of S-loaded activated carbon was put forward by applying characterization methods, including BET, FTIR, XRD and etc. The result showed that the restriction effect of airspeed on removal mercury efficiency was limited. In the initial stage, removal mercury rate and adsorption capacity of element mercury can be raised by increasing mercury concentration. As temperature gets higher, the activated molecule in the system get higher and the removal mercury rate will be promoted. The best effect appeared at 80℃. But when temperature was higher than 80℃, negative effects arose. Dynamic fitting in different stages showed that chemical adsorption was the controlling step of the whole process. Besides, the thermal desorption experiment showed that the removal mercury temperature of s-loaded activated carbon ranged from 300℃ to 450℃, and the

  15. Forest gardening on abandoned terraces links local biomass carbon accumulation to international carbon markets, reverses land degradation, improves food diversity, and increases farmer income

    Science.gov (United States)

    Schmidt, Hans-Peter; Pandit, Bishnu Hari; Kammann, Claudia

    2017-04-01

    project to a carbon capture financing system. All planted trees are GIS inventoried and their yearly biomass carbon up-take is calculated on the base of the average ten-year carbon accumulation. The 25,000 mixed trees accumulate the equivalent of 350 t CO2 per year. At 35 US per t of CO2eq paid in advance by the international community in form of private carbon compensation subscriptions, all costs for the set-up of the forest gardens, their maintenance for three years plus a yearly prime could be paid. After this initial period of three years, the income from tree crops (fruits, nuts, medicine, essential oil, silk, perfume, honey, timber, animal fodder) exceeds by far the (catalyzer) carbon credits providing average crop incomes for the 25,000 trees including secondary mixed cropping of more than 150,000 USD per year. With new processed tree crop products, better-paid jobs are created, the local economy is fostered and the "lost generation" can start to return to their home villages. The objective of this pilot forest garden project was to establish a robust socio-agronomic system that can be multiplied from village to village, increasing soil fertility, protecting abandoned terraces from erosion, replenishing water resources, and generating stable incomes with climate-smart agriculture. The essential catalyst of the project was to link the global need to capture atmospheric carbon and to create negative emissions to slow down climate change with the local capacity to increase biomass growth and to sequester biomass carbon with new low-tech technology (biochar). The financial exchange between global CO2-emmitting communities with local CO2 capturing farmer communities could become a new motor to reverse land degradation, to reestablish ecosystem services, and to develop the rural socio-economy.

  16. Aircraft exhaust sulfur emissions

    Energy Technology Data Exchange (ETDEWEB)

    Brown, R.C.; Anderson, M.R.; Miake-Lye, R.C.; Kolb, C.E. [Aerodyne Research, Inc., Billerica, MA (United States). Center for Chemical and Environmental Physics; Sorokin, A.A.; Buriko, Y.I. [Scientific Research Center `Ecolen`, Moscow (Russian Federation)

    1997-12-31

    The extent to which fuel sulfur is converted to SO{sub 3} during combustion and the subsequent turbine flow in supersonic and subsonic aircraft engines is estimated numerically. The analysis is based on: a flamelet model with non-equilibrium sulfur chemistry for the combustor, and a one-dimensional, two-stream model with finite rate chemical kinetics for the turbine. The results indicate that between 2% and 10% of the fuel sulfur is emitted as SO{sub 3}. It is also shown that, for a high fuel sulfur mass loading, conversion in the turbine is limited by the level of atomic oxygen at the combustor exit, leading to higher SO{sub 2} oxidation efficiency at lower fuel sulfur loadings. While SO{sub 2} and SO{sub 3} are the primary oxidation products, the model results further indicate H{sub 2}SO{sub 4} levels on the order of 0.1 ppm for supersonic expansions through a divergent nozzle. This source of fully oxidized S(6) (SO{sub 3} + H{sub 2}SO{sub 4}) exceeds previously calculated S(6) levels due to oxidation of SO{sub 2} by OH in the exhaust plume outside the engine nozzle. (author) 26 refs.

  17. Legume adaptation to sulfur deficiency revealed by comparing nutrient allocation and seed traits in Medicago truncatula.

    Science.gov (United States)

    Zuber, Hélène; Poignavent, Germain; Le Signor, Christine; Aimé, Delphine; Vieren, Eric; Tadla, Charlène; Lugan, Raphaël; Belghazi, Maya; Labas, Valérie; Santoni, Anne-Lise; Wipf, Daniel; Buitink, Julia; Avice, Jean-Christophe; Salon, Christophe; Gallardo, Karine

    2013-12-01

    Reductions in sulfur dioxide emissions and the use of sulfur-free mineral fertilizers are decreasing soil sulfur levels and threaten the adequate fertilization of most crops. To provide knowledge regarding legume adaptation to sulfur restriction, we subjected Medicago truncatula, a model legume species, to sulfur deficiency at various developmental stages, and compared the yield, nutrient allocation and seed traits. This comparative analysis revealed that sulfur deficiency at the mid-vegetative stage decreased yield and altered the allocation of nitrogen and carbon to seeds, leading to reduced levels of major oligosaccharides in mature seeds, whose germination was dramatically affected. In contrast, during the reproductive period, sulfur deficiency had little influence on yield and nutrient allocation, but the seeds germinated slowly and were characterized by low levels of a biotinylated protein, a putative indicator of germination vigor that has not been previously related to sulfur nutrition. Significantly, plants deprived of sulfur at an intermediary stage (flowering) adapted well by remobilizing nutrients from source organs to seeds, ensuring adequate quantities of carbon and nitrogen in seeds. This efficient remobilization of photosynthates may be explained by vacuolar sulfate efflux to maintain leaf metabolism throughout reproductive growth, as suggested by transcript and metabolite profiling. The seeds from these plants, deprived of sulfur at the floral transition, contained normal levels of major oligosaccharides but their germination was delayed, consistent with low levels of sucrose and the glycolytic enzymes required to restart seed metabolism during imbibition. Overall, our findings provide an integrative view of the legume response to sulfur deficiency.

  18. Corrosion-resistant sulfur concretes

    Science.gov (United States)

    McBee, W. C.; Sullivan, T. A.; Jong, B. W.

    1983-04-01

    Sulfur concretes have been developed by the Bureau of Mines as construction materials with physical and mechanical properties that suit them for use in acid and salt corrosive environments where conventional concretes fail. Mixture design methods were established for preparing sulfur concretes using different types of aggregates and recently developed mixed-modified sulfur cements. Bench-scale testing of the sulfur concretes has shown their potential value. Corrosion resistance, strength, and durability of sulfur concrete are superior to those of conventional materials. Field in situ evaluation tests of the sulfur concretes as replacement for conventional concrete materials are in progress in corrosive areas of 24 commercial chemical, fertilizer, and metallurgical plants.

  19. High Area Capacity Lithium-Sulfur Full-cell Battery with Prelitiathed Silicon Nanowire-Carbon Anodes for Long Cycling Stability

    Science.gov (United States)

    Krause, Andreas; Dörfler, Susanne; Piwko, Markus; Wisser, Florian M.; Jaumann, Tony; Ahrens, Eike; Giebeler, Lars; Althues, Holger; Schädlich, Stefan; Grothe, Julia; Jeffery, Andrea; Grube, Matthias; Brückner, Jan; Martin, Jan; Eckert, Jürgen; Kaskel, Stefan; Mikolajick, Thomas; Weber, Walter M.

    2016-06-01

    We show full Li/S cells with the use of balanced and high capacity electrodes to address high power electro-mobile applications. The anode is made of an assembly comprising of silicon nanowires as active material densely and conformally grown on a 3D carbon mesh as a light-weight current collector, offering extremely high areal capacity for reversible Li storage of up to 9 mAh/cm2. The dense growth is guaranteed by a versatile Au precursor developed for homogenous Au layer deposition on 3D substrates. In contrast to metallic Li, the presented system exhibits superior characteristics as an anode in Li/S batteries such as safe operation, long cycle life and easy handling. These anodes are combined with high area density S/C composite cathodes into a Li/S full-cell with an ether- and lithium triflate-based electrolyte for high ionic conductivity. The result is a highly cyclable full-cell with an areal capacity of 2.3 mAh/cm2, a cyclability surpassing 450 cycles and capacity retention of 80% after 150 cycles (capacity loss <0.4% per cycle). A detailed physical and electrochemical investigation of the SiNW Li/S full-cell including in-operando synchrotron X-ray diffraction measurements reveals that the lower degradation is due to a lower self-reduction of polysulfides after continuous charging/discharging.

  20. Ion-molecule reactions of O,S-dimethyl methylphosphonothioate: evidence for intramolecular sulfur oxidation during VX perhydrolysis.

    Science.gov (United States)

    McAnoy, Andrew M; Williams, Jilliarne; Paine, Martin R L; Rogers, Michael L; Blanksby, Stephen J

    2009-12-18

    The alkaline perhydrolysis of the nerve agent O-ethyl S-[2-(diisopropylamino)ethyl] methylphosphonothioate (VX) was investigated by studying the ion-molecule reactions of HOO(-) with O,S-dimethyl methylphosphonothioate in a modified linear ion-trap mass spectrometer. In addition to simple proton transfer, two other abundant product ions are observed at m/z 125 and 109 corresponding to the S-methyl methylphosphonothioate and methyl methylphosphonate anions, respectively. The structure of these product ions is demonstrated by a combination of collision-induced dissociation and isotope-labeling experiments that also provide evidence for their formation by nucleophilic reaction pathways, namely, (i) S(N)2 at carbon to yield the S-methyl methylphosphonothioate anion and (ii) nucleophilic addition at phosphorus affording a reactive pentavalent intermediate that readily undergoes internal sulfur oxidation and concomitant elimination of CH(3)SOH to yield the methyl methylphosphonate anion. Consistent with previous solution phase observations of VX perhydrolysis, the toxic P-O cleavage product is not observed in this VX model system and theoretical calculations identify P-O cleavage to be energetically uncompetitive. Conversely, intramolecular sulfur oxidation is calculated to be extremely exothermic and kinetically accessible explaining its competitiveness with the facile gas phase proton transfer process. Elimination of a sulfur moiety deactivates the nerve agent VX and thus the intramolecular sulfur oxidation process reported here is also able to explain the selective perhydrolysis of the nerve agent to relatively nontoxic products.

  1. Preparation and performance of a sulfur/graphene composite for rechargeable lithium-sulfur battery

    Science.gov (United States)

    Zhang, Feifei; Dong, Yunhui; Huang, Yun; Huang, Gang; Zhang, Xinbo; Wang, Limin

    2012-01-01

    The lithium-sulfur (Li-S) battery is a promising electrochemical system that has high theoretical capacity. The sulfur/graphene nanosheets (S/GNS) composite is prepared through thermal reduction between the sulfur (S) and graphene oxide (GO). The morphology and composition of the composite are analyzed by means of x-ray powder diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopic (EDS) characterization. It is found that the element S distributed uniformly between the layers of GNS. Graphene with a two-dimensional structure of carbon atoms is employed as a conductive and absorbing agent for the S cathode materials of rechargeable Li-S battery. The S/GNS composite cathode shows a specific electrochemical capacity, which is about 1598 mAh g-1 S at the initial discharge and remains above 670 mAh g-1 after 80 cycles.

  2. Low contribution of internal metabolism to carbon dioxide emissions along lotic and lentic environments of a Mediterranean fluvial network

    Science.gov (United States)

    Gómez-Gener, Lluís.; Schiller, Daniel; Marcé, Rafael; Arroita, Maite; Casas-Ruiz, Joan Pere; Staehr, Peter Anton; Acuña, Vicenç; Sabater, Sergi; Obrador, Biel

    2016-12-01

    Inland waters are significant sources of carbon dioxide (CO2) to the atmosphere. CO2 supersaturation and subsequent CO2 emissions from inland waters can be driven by internal metabolism, external inputs of dissolved inorganic carbon (DIC) derived from the catchment, and other processes (e.g., internal geochemical reactions of calcite precipitation or photochemical mineralization of organic solutes). However, the sensitivity of the magnitude and sources of CO2 emissions to fluvial network hydromorphological alterations is still poorly understood. Here we investigated both the magnitude and sources of CO2 emissions from lotic (i.e., running waters) and lentic (i.e., stagnant waters associated to small dams) waterbodies of a Mediterranean fluvial network by computing segment-scale mass balances of CO2. Our results showed that sources other than internal metabolism sustained most (82%) of the CO2 emissions from the studied fluvial network. The magnitude and sources of CO2 emissions in lotic waterbodies were highly dependent on hydrology, with higher emissions dominated by DIC inputs derived from the catchment during high flows and lower emissions partially fueled by CO2 produced biologically within the river during low flows. In contrast, CO2 emissions in lentic waterbodies were low, relatively stable over the time and the space, and dominated by DIC inputs from the catchment regardless of the different hydrological situations. Overall, our results stress the sensitivity of fluvial networks to human activities and climate change and particularly highlight the role of hydromorphological conditions on modulating the magnitude and sources of CO2 emissions from fluvial networks.

  3. The role of plasma-surface interactions in process chemistry: Mechanistic studies of a-carbon nitride deposition and sulfur fluoride/oxygen etching of silicon

    Science.gov (United States)

    Stillahn, Joshua M.

    The molecular level chemistry of a-CNx deposition in plasma discharges was studied with emphasis on the use of CH 3CN and BrCN as single source precursors for these films. Characterization of the global deposition behavior in these systems indicates that the resulting films are relatively smooth and contain significant levels of N-content, with N/C > 0.3. Notably, films obtained from BrCN plasmas are observed to delaminate upon their exposure to atmosphere, and preliminary investigation of this behavior is presented. Detailed chemical investigation of the deposition process focuses primarily on the contributions of CN radicals, which were characterized from their origin in the gas phase to their reaction at the a-CNx film surface. Laser-induced fluorescence studies suggest that CN is formed through electron impact dissociation of the precursor species and that this breakdown process produces CN with high internal energies, having rotational and vibrational temperatures on the order of 1000 K and 5000 K, respectively. Measurement of CN surface reactivity coefficients in CH3CN plasmas show that CN reacts with a probability of ˜94%, irrespective of the deposition conditions; this information, combined with gas phase and film characterization data, leads to the conclusion that CN internal energies exert a strong influence on their surface reactivity and that these surface reactions favor their incorporation into the a-CN x film. Moreover, this correlation is shown to hold for several other plasma radicals studied in our lab, suggesting the potential for developing a general model for predicting surface interactions of activated gas phase species. This dissertation also presents results from studies of SF6/O 2 etching of Si. Addition of O2 to the feed gas leads to the generation of SO2, among other species, and gas phase characterization data suggest that SO2 may act as a sink for atomic S, preventing the reformation of SOxFy (y > 0) and thus promoting generation of

  4. Internal carbon source from sludge pretreated by microwave-H2O2 for nutrient removal in A2/O-membrane bioreactors.

    Science.gov (United States)

    Xu, Rongle; Zhang, Qing; Tong, Juan; Wei, Yuansong; Fan, Yaobo

    2015-01-01

    To improve the nutrient removal, the feasibility was studied for the organics released from sludge pretreated by microwave-H2O2 process (MHP) to be used as internal carbon source in two A2/O-membrane bioreactors (MBRs). The experiments were conducted for the nutrient removal and the membrane fouling. The results showed that the removal efficiencies of TN and TP were improved by 11% and 28.34%, respectively, as C/N ratio was adjusted to 8 by adding the internal carbon source, and the ratio of soluble chemical oxygen demand (sCOD) consumed easily for denitrification was about 46% of the total sCOD in the internal carbon source. The addition of the internal carbon sources did not lead to severe membrane fouling in the experimental A2/O-MBR. It is implied that the organics released from sludge pretreated by MHP could be used as the internal carbon source to enhance the nutrient removal in A2/O-MBRs.

  5. Relationships between Stomatal Behavior and Internal Carbon Dioxide Concentration in Crassulacean Acid Metabolism Plants.

    Science.gov (United States)

    Cockburn, W

    1979-06-01

    Measurements of internal gas phase CO(2) concentration, stomatal resistance, and acid content were made in Crassulacean acid metabolism plants growing under natural conditions. High CO(2) concentrations, sometimes in excess of 2%, were observed during the day in a range of taxonomically widely separated plants (Opuntia ficus-indica L., Opuntia basilaris Engelm. and Bigel., Agave desertii Engelm., Yucca schidigera Roezl. ex Ortiges, Ananas comosus [L.] Merr., Aloe vera L., Cattleya sp. and Phalanopsis sp.) and below ambient air concentrations were observed at night.Stomatal resistance was always high when CO(2) concentration was high and experiments in which attempts were made to manipulate internal CO(2) concentrations gave data consistent with stomatal behavior in Crassulacean acid metabolism being controlled by internal CO(2) concentration. Exogenous CO(2) applied in darkness at a concentration similar to those observed in the light caused stomatal resistance to increase.In pads of Opuntia basilaris Engelm. and Bigel. subjected to severe water stress internal gas phase CO(2) concentrations exhibited fluctuations opposite in phase to fluctuations in acid content. Stomatal resistance remained high and the opening response to low CO(2) concentration was almost entirely eliminated.

  6. Mass-dependent sulfur isotope fractionation during reoxidative sulfur cycling

    DEFF Research Database (Denmark)

    Pellerin, André; Bui, Thi Hao; Rough, Mikaella

    2015-01-01

    of Mangrove Lake appears to include sulfide oxidation to elemental sulfur followed by the disproportionation of the elemental sulfur to sulfate and sulfide. This model also indicates that the reoxidative sulfur cycle of Mangrove Lake turns over from 50 to 80% of the sulfide produced by microbial sulfate...... that the two processes cannot be discriminated from each other....

  7. Lunar Sulfur Capture System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Lunar Sulfur Capture System (LSCS) is an innovative method to recover sulfur compounds from lunar soil using sorbents derived primarily from in-situ resources....

  8. Lunar Sulfur Capture System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Lunar Sulfur Capture System (LSCS) is an innovative method to capture greater than 90 percent of sulfur gases evolved during thermal treatment of lunar soils....

  9. Steam-Coal Gasification Using CaO and KOH for in Situ Carbon and Sulfur Capture

    Energy Technology Data Exchange (ETDEWEB)

    Siefert, Nicholas S. [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States); Carnegie Mellon Univ., Pittsburgh, PA (United States); Shekhawat, Dushyant [National Energy Technology Lab. (NETL), Morgantown, WV (United States); Litster, Shawn [Carnegie Mellon Univ., Pittsburgh, PA (United States); Berry, David A. [National Energy Technology Lab. (NETL), Morgantown, WV (United States)

    2013-08-15

    We present experimental results of coal gasification with and without the addition of calcium oxide and potassium hydroxide as dual-functioning catalyst-capture agents. Using two different coal types and temperatures between 700 and 900 °C, we studied the effect of these catalyst-capture agents on (1) the syngas composition, (2) CO2 and H2S capture, and (3) the steam-coal gasification kinetic rate. The syngas composition from the gasifier was roughly 20% methane, 70% hydrogen, and 10% other species when a CaO/C molar ratio of 0.5 was added. We demonstrated significantly enhanced steam–coal gasification kinetic rates when adding small amounts of potassium hydroxide to coal when operating a CaO-CaCO3 chemical looping gasification reactor. For example, the steam–coal gasification kinetic rate increased 250% when dry mixing calcium oxide at a Ca/C molar ratio of 0.5 with a sub-bituminous coal, and the kinetic rate increased 1000% when aqueously mixing calcium oxide at a Ca/C molar ratio of 0.5 along with potassium hydroxide at a K/C molar ratio of 0.06. In addition, we conducted multi-cycle studies in which CaCO3 was calcined by heating to 900 °C to regenerate the CaO, which was then reused in repeated CaO-CaCO3 cycles. The increased steam-coal gasification kinetics rates for both CaO and CaO + KOH persisted even when the material was reused in six cycles of gasification and calcination. The ability of CaO to capture carbon dioxide decreased roughly 2-4% per CaO-CaCO3 cycle. We also discuss an important application of this combined gasifier-calciner to electricity generation and selling the purge stream as a precalcined feedstock to a cement kiln. In this scenario, the amount of purge stream required is fixed not by the degradation in the capture ability but rather by the requirements at the cement kiln on the amount of CaSO4 and ash in the precalcined feedstock.

  10. Sulfur isotopes in coal constrain the evolution of the Phanerozoic sulfur cycle.

    Science.gov (United States)

    Canfield, Donald E

    2013-05-21

    Sulfate is the second most abundant anion (behind chloride) in modern seawater, and its cycling is intimately coupled to the cycling of organic matter and oxygen at the Earth's surface. For example, the reduction of sulfide by microbes oxidizes vast amounts of organic carbon and the subsequent reaction of sulfide with iron produces pyrite whose burial in sediments is an important oxygen source to the atmosphere. The concentrations of seawater sulfate and the operation of sulfur cycle have experienced dynamic changes through Earth's history, and our understanding of this history is based mainly on interpretations of the isotope record of seawater sulfates and sedimentary pyrites. The isotope record, however, does not give a complete picture of the ancient sulfur cycle. This is because, in standard isotope mass balance models, there are more variables than constraints. Typically, in interpretations of the isotope record and in the absence of better information, one assumes that the isotopic composition of the input sulfate to the oceans has remained constant through time. It is argued here that this assumption has a constraint over the last 390 Ma from the isotopic composition of sulfur in coal. Indeed, these compositions do not deviate substantially from the modern surface-water input to the oceans. When applied to mass balance models, these results support previous interpretations of sulfur cycle operation and counter recent suggestions that sulfate has been a minor player in sulfur cycling through the Phanerozoic Eon.

  11. Minimal sulfur requirement for growth and sulfur-dependent metabolism of the hyperthermophilic archaeon Staphylothermus marinus

    Directory of Open Access Journals (Sweden)

    Xiaolei Hao

    2003-01-01

    Full Text Available Staphylothermus marinus is an anaerobic hyperthermophilic archaeon that uses peptides as carbon and energy sources. Elemental sulfur (S° is obligately required for its growth and is reduced to H2S. The metabolic functions and mechanisms of S° reduction were explored by examining S°-dependent growth and activities of key enzymes present in this organism. All three forms of S° tested—sublimed S°, colloidal S° and polysulfide—were used by S. marinus, and no other sulfur-containing compounds could replace S°. Elemental sulfur did not serve as physical support but appeared to function as an electron acceptor. The minimal S° concentration required for optimal growth was 0.05% (w/v. At this concentration, there appeared to be a metabolic transition from H2 production to S° reduction. Some enzymatic activities related to S°-dependent metabolism, including sulfur reductase, hydrogenase, glutamate dehydrogenase and electron transfer activities, were detected in cell-free extracts of S. marinus. These results indicate that S° plays an essential role in the heterotrophic metabolism of S. marinus. Reducing equivalents generated by the oxidation of amino acids from peptidolysis may be transferred to sulfur reductase and hydrogenase, which then catalyze the production of H2S and H2, respectively.

  12. Zeolites Remove Sulfur From Fuels

    Science.gov (United States)

    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.

  13. Utilization of fumarate by sulfur-reducing bacteria Desulfuromonas sp.

    Directory of Open Access Journals (Sweden)

    O. Сhayka

    2016-08-01

    Full Text Available The main goal of the work was to study the utilization of fumarate by sulfur-reducing bacteria Desulfuromonas sp. under different growth conditions and accumulation of hydrogen sulfide by bacteria in the media with sulfur and different electron donors. Sulfur-reducing bacteria Desulfuromonas sp., isolated from soil in Yazivske sulfur deposit, were used in the reasearch. Bacteria were grown in the medium Postgate C without sulfates. The content of hydrogen sulfide was determined by formation of methylene blue. The content of organic acids (fumarate, succinate, lactate, acetate was determined by high performance liquid chromatography (HPLC. The biomass of cells was determined by the photoelectrocolorymetry method using KFK-3. The highest level of accumulation of hydrogen sulfide by bacteria Desulfuromonas sp. was found in media with sodium lactate and sodium pyruvate. The maximal concentration of hydrogen sulfide was 1.9 mM. Maximal accumulation of biomass was observed in the media with malate, lactate and fumarate with the presence of elemental sulfur. Sulfur-reducing bacteria Desulfuromonas sp. are able to utilize fumarate as an electron donor and acceptor in the absence of elemental sulfur in the medium. After the incubation of Desulfuromonas sp. in the medium with fumarate, chromatographic analysis of culture liquid showed that fumarate is converted to succinate and small quantities of acetate The presence of acetate is, probably, due to the particularaties of the functioning of citric acid cycle in bacteria of the genus Desulfuromonas. Consequently, the results indicate that the fumarate serves as a donor and acceptor of electrons.The simultaneous introduction of two electron donors – fumarate and elemental sulfur – was accompanied by inhibition of sulfur reduction. After an additional source of carbon (sodium lactate and electron acceptor (elemental sulfur was added to the medium with fumarate a fivefold increase of sulfidogenic

  14. Mass concentration and ion composition of coarse and fine particles in an urban area in Beirut: effect of calcium carbonate on the absorption of nitric and sulfuric acids and the depletion of chloride

    Directory of Open Access Journals (Sweden)

    H. Kouyoumdjian

    2006-01-01

    Full Text Available Levels of coarse (PM10-2.5 and fine (PM2.5 particles were determined between February 2004 and January 2005 in the city of Beirut, Lebanon. While low PM mass concentrations were measured in the rainy season, elevated levels were detected during sand storms originating from Arabian desert and/or Africa. Using ATR-FTIR and IC, it was shown that nitrate, sulfate, carbonate and chloride were the main anionic constituents of the coarse particles, whereas sulfate was mostly predominant in the fine particles in the form of (NH42SO4. Ammonium nitrate was not expected to be important because the medium was defined as ammonium poor. In parallel, the cations Ca2+ and Na+ dominated in the coarse, and NH4+, Ca2+ and Na+ in the fine particles. Coarse nitrate and sulfate ions resulted from the respective reactions of nitric and sulfuric acid with a relatively high amount of calcium carbonate. Both CaCO3 and Ca(NO32 crystals identified by ATR-FTIR in the coarse particles were found to be resistant to soaking in water for 24 h but became water soluble when they were formed in the fine particles suggesting, thereby, different growth and adsorption phenomena. The seasonal variational study showed that nitrate and sulfate ion concentrations increased in the summer due to the enhancement of photochemical reactions which facilitated the conversion of NO2 and SO2 gases into NO3- and SO42-, respectively. While nitrate was mainly due to local heavy traffic, sulfates were due to local and long-range transport phenomena. Using the air mass trajectory HYSPLIT model, it was found that the increase in the sulfate concentration correlated with wind vectors coming from Eastern and Central Europe. Chloride levels, on the other hand, were high when wind originated from the sea and low during sand storms. In addition to sea salt, elevated levels of chloride were also attributed to waste mass burning in proximity to the site. In comparison to other neighboring Mediterranean

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

    Science.gov (United States)

    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.

  16. Structure of amorphous sulfur

    CSIR Research Space (South Africa)

    Eichinger, BE

    2001-06-01

    Full Text Available The lambda-transition of elemental sulfur occurring at about 159°C has long been associated with the conversion of cyclic S8 rings (c-S8) to amorphous polymer (a-S) via a ring opening polymerization. It is demonstrated, with the use of both density...

  17. Accidents with sulfuric acid

    Directory of Open Access Journals (Sweden)

    Rajković Miloš B.

    2006-01-01

    Full Text Available Sulfuric acid is an important industrial and strategic raw material, the production of which is developing on all continents, in many factories in the world and with an annual production of over 160 million tons. On the other hand, the production, transport and usage are very dangerous and demand measures of precaution because the consequences could be catastrophic, and not only at the local level where the accident would happen. Accidents that have been publicly recorded during the last eighteen years (from 1988 till the beginning of 2006 are analyzed in this paper. It is very alarming data that, according to all the recorded accidents, over 1.6 million tons of sulfuric acid were exuded. Although water transport is the safest (only 16.38% of the total amount of accidents in that way 98.88% of the total amount of sulfuric acid was exuded into the environment. Human factor was the common factor in all the accidents, whether there was enough control of the production process, of reservoirs or transportation tanks or the transport was done by inadequate (old tanks, or the accidents arose from human factor (inadequate speed, lock of caution etc. The fact is that huge energy, sacrifice and courage were involved in the recovery from accidents where rescue teams and fire brigades showed great courage to prevent real environmental catastrophes and very often they lost their lives during the events. So, the phrase that sulfuric acid is a real "environmental bomb" has become clearer.

  18. Catalysts for the reduction of SO{sub 2} to elemental sulfur

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Y.; Yu, Q.Q.; Chang, S.G. [Lawrence Berkeley Lab., Berkeley, CA (United States)

    1995-11-01

    Catalysts have been prepared for the reduction of SO{sub 2} to elemental sulfur by synthesis gas. A catalyst allows to obtain more than 97% yield of elemental sulfur with a single-stage reactor at 540{degrees}C. A lifetime test has been successfully performed. The mass balance of sulfur and carbon has been checked. The effect of H{sub 2}S, COS, and H{sub 2}O has been studied.

  19. The coordination of sulfur in synthetic and biogenic Mg calcites: The red coral case

    Science.gov (United States)

    Perrin, J.; Rivard, C.; Vielzeuf, D.; Laporte, D.; Fonquernie, C.; Ricolleau, A.; Cotte, M.; Floquet, N.

    2017-01-01

    Sulfur has been recognized in biogenic calcites for a long time. However, its structural position is matter of debate. For some authors, sulfur is a marker of the organic matrix while it is part of the calcite structure itself for others. To better understand the place of sulfur in calcite, sulfated magnesian calcites (S-MgCalcite) have been synthetized at high pressure and temperature and studied by μ-XANES spectroscopy. S-MgCalcite XANES spectra show two different types of sulfur: sulfate (SO42-) as a predominant species and a small contribution of sulfite (SO32-), both substituting for carbonate ions in the calcite structure. To address the question of the position of sulfur in biogenic calcites, the oxidation states of sulfur in the skeleton and organic tissues of Corallium rubrum have been investigated by micro X-ray fluorescence (μ-XRF) and sulfur K-edge micro X-ray absorption near edge structure (μ-XANES) spectroscopy at the European Synchrotron Radiation Facility (ESRF, Grenoble, France) on beamline ID21. In the skeleton, sulfur is mainly present as oxidized sulfur SO42- (+VI), plus a weak sulfite contribution. XANES spectra indicate that sulfur is inorganically incorporated as sulfur structurally substituted to carbonate ions (SSS). Although an organic matrix is present in the red coral skeleton, reduced organic sulfur could not be detected by μ-XANES spectroscopy in the skeleton probably due to low organic/inorganic sulfur ratio. In the organic tissues surrounding the skeleton, several sulfur oxidation states have been detected including disulfide (S-S), thioether (R-S-CH3), sulfoxide (SO2), sulfonate (SO2O-) and sulfate (SO42-). The unexpected occurrence of inorganic sulfate within the organic tissues suggests the presence of pre-organized organic/inorganic complexes in the circulatory system of the red coral, precursors to biomineralization ahead of the growth front.

  20. 国际碳税方案的比较分析%Comparative Analysis of International Carbon Tax Options

    Institute of Scientific and Technical Information of China (English)

    王珲

    2012-01-01

    碳税作为一种控制二氧化碳排放的经济手段受到许多学者的青睐,国外一些学者主张通过在国际层面实行碳税来实现全球二氧化碳减排的目标,并提出了不同的设计构想.但至今仍没有研究者对国际上的国际碳税提议进行系统的归纳.对已有国际碳税提议进行归纳和分析即成为本文的目的.本文将已有典型的国际碳税提议归纳成四种方案,即统一的国际税方案、有差异的国际税方案、统一的国内税方案和国内税+边境调节税方案,分别阐述了每种方案的内容和特征,并运用比较分析的方法从成本效益、公平性、参与广泛性及可操作性四个方面对所归纳的四种方案进行对比分析.通过分析得出,如果仅基于成本效益、公平性、参与广泛性及可操作性四个指标,前三种方案差别不大,但都明显优于第四种方案,因此第四种方案是最劣的.但如果考虑到方案实行的现实条件和推动力,最劣的第四种方案是短期内最可能实现的,并且,最优的国际碳税方案可能需由最劣的方案逐次演化而成,而难以直接实现.%As one of the economic policies to control carbon dioxide (CO2) emissions, carbon tax is favored by many scholars. Some foreign scholars advocate that carbon tax should be implemented worldwide to reach the goal of global carbon emission abatement and put forth a few different proposals. However, so far, there is no study focusing on the summary and induction of these proposals. In this article the existing proposals are summarized and analyzed. The Typical proposals are sorted into four international carbon tax options, which are Uniform International Taxes, Non-uniform International Taxes, Harmonized Domestic Taxes and Domestic Taxes and Border-Tax Adjustment, and their main contents and features are described respectively, followed by comparisons of these options in the perspectives of cost-effectiveness, equity

  1. A modular framework for management of complexity in international forest-carbon policy

    Science.gov (United States)

    Law, Elizabeth A.; Thomas, Sebastian; Meijaard, Erik; Dargusch, Paul J.; Wilson, Kerrie A.

    2012-03-01

    Complex and variable ecological and social settings make the programme on reducing emissions through avoided deforestation, forest degradation and other forestry activities in developing countries (REDD+) a challenging policy to design. The total value to society of each type of REDD+ outcome is dependent on the fundamentally different risk profiles of alternative forest-management approaches and their scope and potential for co-benefits. We suggest a modular policy framework for REDD+ that distinguishes and differentially compensates the distinct outcomes. This could represent an improved framework to promote and manage incentives for effective forest-carbon initiatives, offer better scope to find common ground in policy negotiations and allow faster adaptation of policy to an uncertain future.

  2. 3D collagen scaffolds coated with multiwalled carbon nanotubes: initial cell attachment to internal surface.

    Science.gov (United States)

    Hirata, Eri; Uo, Motohiro; Nodasaka, Yoshinobu; Takita, Hiroko; Ushijima, Natsumi; Akasaka, Tsukasa; Watari, Fumio; Yokoyama, Atsuro

    2010-05-01

    The cell adhesion in a multiwalled carbon nanotube-coated collagen sponge (MWCNT-coated sponge) was investigated. Immediately after seeding, the cells adhered to the inner surface of the MWCNT-coated sponge and a significantly larger number of cells were observed there than for a pure collagen sponge used as control. On the MWCNT-coated sponge, the cells appeared favorable adhesion and spread in the early stages in the center part of the sponge which cells rarely attached without MWCNT-coating. It was suggested that the physical structure of MWCNTs was effective for initial adhesion of cells from the result of serum-free culture. MWCNT-coating makes the material a suitable three-dimensional scaffold for cell culturing, as opposed to other scaffold systems where such an effect is not seen.

  3. Effect of an Internal Heat Exchanger on Performance of the Transcritical Carbon Dioxide Refrigeration Cycle with an Expander

    Directory of Open Access Journals (Sweden)

    Zhenying Zhang

    2014-11-01

    Full Text Available The effect of the internal heat exchanger (IHE on the performance of the transcritical carbon dioxide refrigeration cycle with an expander is analyzed theoretically on the basis of the first and second laws of thermodynamics. The possible parameters affecting system efficiency such as heat rejection pressure, gas cooler outlet temperature, evaporating temperature, expander isentropic efficiency and IHE effectiveness are investigated. It is found that the IHE addition in the carbon dioxide refrigeration cycle with an expander increases the specific cooling capacity and compression work, and decreases the optimum heat rejection pressure and the expander output power. An IHE addition does not always improve the system performance in the refrigeration cycle with an expander. The throttle valve cycle with IHE provides a 5.6% to 17% increase in maximum COP compared to that of the basic cycle. For the ideal expander cycle with IHE, the maximum COP is approximately 12.3% to 16.1% lower than the maximum COP of the cycle without IHE. Whether the energy efficiency of the cycle by IHE can be improved depends on the isentropic efficiency level of the expander. The use of IHE is only applicable in the cases of lower expander isentropic efficiencies or higher gas cooler exit temperatures for the refrigeration cycle with an expander from the view of energy efficiency.

  4. Measuring morphology and density of internally mixed black carbon with SP2 and VTDMA: new insight to absorption enhancement of black carbon in the atmosphere

    Directory of Open Access Journals (Sweden)

    Y. X. Zhang

    2015-11-01

    Full Text Available The morphology and density of black carbon (BC cores in internally mixed BC (In-BC particles affects their mixing state and absorption enhancement. In this work, we developed a new method to measure the morphology and effective density of BC cores of ambient In-BC particles using a single particle soot photometer (SP2 and a volatility tandem differential mobility analyzer (VTDMA, during the CAREBeijing-2013 campaign from 8 to 27 July 2013 at Xianghe Observatory. The new measurement system can select size-resolved ambient In-BC particles and measure the mobility size and mass of In-BC cores. The morphology and effective density of ambient In-BC cores are then calculated. For In-BC cores in the atmosphere, changes in the dynamic shape factor (χ and effective density (ρeff can be characterized as a function of aging process (Dp ⁄ Dc measured by SP2 and VTDMA. During an intensive field study, the ambient In-BC cores had an average χ of ∼ 1.2 and an average density of ∼ 1.2 g cm−3, indicating that ambient In-BC cores have a near-spherical shape with an internal void of ∼ 30 %. With the measured morphology and density, the average shell ⁄ core ratio and absorption enhancement (Eab from ambient black carbon were estimated to be 2.1–2.7 and 1.6–1.9 for different sizes of In-BC particles at 200–350 nm. When assuming the In-BC cores have a void-free BC sphere with a density of 1.8 g cm−3, the shell ⁄ core ratio and Eab could be overestimated by ∼ 13 and ∼ 17 % respectively. The new approach developed in this work will help improve calculations of mixing state and optical properties of ambient In-BC particles by quantification of changes in morphology and density of ambient In-BC cores during aging process.

  5. Biotransformation of sulfur and nitrogen oxides in stack gases

    Energy Technology Data Exchange (ETDEWEB)

    Govind, R.; Puligadda, R. [Univ. of Cincinnati, OH (United States); Bishop, D.F. [Environmental Protection Agency, Cincinnati, OH (United States)

    1995-10-01

    The Nation`s large supply of high sulfur coal and increasingly stringent emission regulation led to priority development of advanced innovative processes for treating pollutants in flue gases from coal combustion. The principal pollutants in flue gases, sulfur oxides (SO{sub 2},SO{sub 3}) and nitrogen oxides (NO{sub x}) cause acid rain. Thus, the Department of Energy`s Clean Coal Program is funding projects to commercialize technologies that minimize emission of sulfur and nitrogen oxides at power plants. This report describes the controlled use of bioconversion processes to remove the oxides from flue gas. Two bioreactor experiments were conducted to investigate the removal of sulfur dioxide, nitrogen oxides, and carbon dioxide from stack gases.

  6. Partitioning uncertainty in ocean carbon uptake projections: Internal variability, emission scenario, and model structure

    Science.gov (United States)

    Lovenduski, Nicole S.; McKinley, Galen A.; Fay, Amanda R.; Lindsay, Keith; Long, Matthew C.

    2016-09-01

    We quantify and isolate the sources of projection uncertainty in annual-mean sea-air CO2 flux over the period 2006-2080 on global and regional scales using output from two sets of ensembles with the Community Earth System Model (CESM) and models participating in the 5th Coupled Model Intercomparison Project (CMIP5). For annual-mean, globally-integrated sea-air CO2 flux, uncertainty grows with prediction lead time and is primarily attributed to uncertainty in emission scenario. At the regional scale of the California Current System, we observe relatively high uncertainty that is nearly constant for all prediction lead times, and is dominated by internal climate variability and model structure, respectively in the CESM and CMIP5 model suites. Analysis of CO2 flux projections over 17 biogeographical biomes reveals a spatially heterogenous pattern of projection uncertainty. On the biome scale, uncertainty is driven by a combination of internal climate variability and model structure, with emission scenario emerging as the dominant source for long projection lead times in both modeling suites.

  7. Effects of sulfur oxides on eicosanoids

    Energy Technology Data Exchange (ETDEWEB)

    Chen, L.C.; Miller, P.D.; Amdur, M.O. (New York Univ. Medical Center, Tuxedo (USA))

    1989-01-01

    Ultrafine metal oxides and SO2 react during coal combustion or smelting operations to form primary emissions coated with an acidic SOx layer. Ongoing work in this laboratory has examined the effects of sulfur oxides on pulmonary functions of guinea pigs. We have previously reported that 20 micrograms/m3 acidic sulfur oxide as a surface layer on ultrafine ZnO particles decreases lung volumes, decreases carbon monoxide diffusing capacity, and causes lung inflammation in guinea pigs after 4 daily 3-h exposures. It also produces bronchial hypersensitivity following a single 1-h exposure. The importance of this surface layer is demonstrated by our observation that 200 micrograms/m3 of sulfuric acid droplets of equivalent size are needed to produce the same degree of hypersensitivity. This study characterized the concentration-dependent effects of in vivo exposures to sulfur oxides on arachidonic acid metabolism in the guinea pig lung, and investigated the time course and the relation between eicosanoid composition and pulmonary functions. We focused specifically on four cyclooxygenase metabolites of arachidonic acid, that is, prostaglandins (PG) E1, F2 alpha, 6-keto prostaglandin F1 alpha, and thromboxane (Tx) B2, and two groups of sulfidopeptide leukotrienes (C4, D4, E4, and F4). Guinea pigs were exposed to ultrafine ZnO aerosol (count median diameter = 0.05 microns, sigma g = 1.80) with a layer of acidic sulfur oxide on the surface of the particles. Lung lavage was collected after exposures, and the levels of arachidonic acid metabolites were determined using radioimmunoassay (RIA). Concentration-dependent promotion of PGF2 alpha and concentration-dependent suppression of LtB4 were observed. The increased PGF2 alpha was associated with depressed vital capacity and diffusing capacity of the lungs measured in guinea pigs exposed to the same atmosphere described in a previous study.

  8. Quantifying Carbon Financial Risk in the International Greenhouse Gas Market: An Application Using Remotely-Sensed Data to Align Scientific Uncertainty with Financial Decisions

    Science.gov (United States)

    Hultman, N. E.

    2002-12-01

    A common complaint about environmental policy is that regulations inadequately reflect scientific uncertainty and scientific consensus. While the causes of this phenomenon are complex and hard to discern, we know that corporations are the primary implementers of environmental regulations; therefore, focusing on how policy relates scientific knowledge to corporate decisions can provide valuable insights. Within the context of the developing international market for greenhouse gas emissions, I examine how corporations would apply finance theory into their investment decisions for carbon abatement projects. Using remotely-sensed ecosystem scale carbon flux measurements, I show how to determine much financial risk of carbon is diversifiable. I also discuss alternative, scientifically sound methods for hedging the non-diversifiable risks in carbon abatement projects. In providing a quantitative common language for scientific and corporate uncertainties, the concept of carbon financial risk provides an opportunity for expanding communication between these elements essential to successful climate policy.

  9. Variations in the chemical and stable isotope composition of carbon and sulfur species during organic-rich sediment alteration: An experimental and theoretical study of hydrothermal activity at guaymas basin, gulf of california

    Science.gov (United States)

    Seewald, Jeffrey S.; Seyfried, W.E.; Shanks, Wayne C.

    1994-01-01

    at sediment-covered spreading centers. Our data show that the sulfur isotope composition of hydrothermal Sulfide minerals in Guaymas Basin can be explained by derivation of S from diagenetic sulfide and seawater sulfate. Basaltic S may also contribute to hydrothermal sulfide precipitates but is not required to explain their isotopic composition. Estimates of seawater/ sediment mass ratios based on sulfur isotopic composition of sulfide minerals and the abundance of dissolved NH3 in vent fluids range from 3-29 during hydrothermal circulation. Sources of C in Guaymas Basin hydrothermal fluids include thermal degradation of organic matter, bacteriogenic methane production, and dissolution of diagenetic carbonate. ?? 1994.

  10. Variations in the chemical and stable isotope composition of carbon and sulfur species during organic-rich sediment alteration: An experimental and theoretical study of hydrothermal activity at guaymas basin, gulf of california

    Science.gov (United States)

    Seewald, Jeffrey S.; Seyfried, William E., Jr.; Shanks, Wayne C., III

    1994-11-01

    hydrothermal systems at sediment-covered spreading centers. Our data show that the sulfur isotope composition of hydrothermal Sulfide minerals in Guaymas Basin can be explained by derivation of S from diagenetic sulfide and seawater sulfate. Basaltic S may also contribute to hydrothermal sulfide precipitates but is not required to explain their isotopic composition. Estimates of seawater/ sediment mass ratios based on sulfur isotopic composition of sulfide minerals and the abundance of dissolved NH 3 in vent fluids range from 3-29 during hydrothermal circulation. Sources of C in Guaymas Basin hydrothermal fluids include thermal degradation of organic matter, bacteriogenic methane production, and dissolution of diagenetic carbonate.

  11. Non-linear model reduction and control of molten carbonate fuel cell systems with internal reforming

    Energy Technology Data Exchange (ETDEWEB)

    Sheng, Min

    2007-10-12

    Currently, the process design of fuel cells and the development of control strategies is mainly based on heuristic methods. Fuel cell models are often too complex for control purposes, or they are developed for a specific type of fuel cell and valid only in a small range of operation conditions. The application of fuel cell models to controller design is still limited. Furthermore, suitable and simple-to-implement design strategies for fuel cell control remain an open area. There is thus a motivation for simplifying dynamic models for process control applications and for designing suitable control strategies for fuel cells. This is the main objective of this work. As an application example, the 250 kW industrial molten carbonate fuel cell (MCFC) system HotModule by MTU CFC Solutions, Germany is considered. A detailed dynamic two-dimensional spatially distributed cross-flow model of a MCFC from literature is taken as a starting point for the investigation. In Chapter 2, two simplified model versions are derived by incorporating additional physical assumptions. One of the simplified models is extended to a three-dimensional stack model to deal with physical and chemical phenomena in the stack. Simulations of the stack model are performed in Chapter 3 in order to calculate the mass and temperature distributions in the direction perpendicular to the electrode area. The other simplified model forms the basis for a low order reduced model that is derived in Chapter 4. The reduced-order model is constructed by application of the Karhunen-Loeve Galerkin method. The spatial temperature, concentration and potential profiles are approximated by a set of orthogonal time independent spatial basis functions. Problem specific basis functions are generated numerically from simulation data of the detailed reference model. The advantage of this approach is that a small number of basis functions suffices in order to approximate the solution of the detailed model very well. The

  12. Molecular dynamics simulation of SnF2 nanostructures in the internal channels of single-walled carbon nanotubes

    Science.gov (United States)

    Gotlib, I. Yu.; Ivanov-Schitz, A. K.; Murin, I. V.; Petrov, A. V.; Romantsov, G. A.; Zakalyukin, R. M.

    2014-07-01

    A molecular dynamics simulation of solid tin(II) fluoride nanostructures formed in internal channels of single-walled carbon nanotubes (SWCNTs) has been performed using two types of model potentials—without and with inclusion of the polarization of ions. For the potential taking into account the polarization of ions, an ordered SnF2@SWCNT structure is reproduced: in SWCNT(10, 10), it has the form of the SnF2 internal nanotube. At the same time, the SnF2@SWCNT(11,11) structure is substantially disordered (glass-like). It has been found that heating of the SnF2@SWCNT model system produces a superionic state characterized by a high mobility of fluorine ions without migration of tin ions. The model potentials disregard the covalent character of Sn-F bonds and the specific interactions of a lone electron pair of the Sn2+ ion. This makes it impossible to completely reproduce the properties of SnF2 at normal pressures. However, some characteristics of the SnF2 high-pressure modification can be reproduced if the polarization of ions is taken into account.

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

    Science.gov (United States)

    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.

  14. Well materials durability in case of carbon dioxide and hydrogen sulphide geological sequestration; Durabilite des materiaux de puits petroliers dans le cadre d'une sequestration geologique de dioxyde de carbone et d'hydrogene sulfure

    Energy Technology Data Exchange (ETDEWEB)

    Jacquemet, N

    2006-01-15

    The geological sequestration of carbon dioxide (CO{sub 2}) and hydrogen sulphide (H{sub 2}S) is a promising solution for the long-term storage of these undesirable gases. It consists in injecting them via wells into deep geological reservoirs. The steel and cement employed in the well casing can be altered and provide pathways for leakage with subsequent human and environmental consequences. The materials ageing was investigated by laboratory experiments in geologically relevant P-T conditions. A new experimental and analysis procedure was designed for this purpose. A numerical approach was also done. The cement and steel were altered in various fluid phases at 500 bar-120 C and 500 bar-200 C: a brine, a brine saturated with H{sub 2}S-CO{sub 2}, a mixture of brine saturated with H{sub 2}S-CO{sub 2} and of supercritical H{sub 2}S-CO{sub 2} phase, a dry supercritical H{sub 2}S-CO{sub 2} phase without liquid water. In all cases, two distinct reactions are observed: the cement carbonation by the CO{sub 2} and the steel sulfidation by the H{sub 2}S. The carbonation and sulfidation are respectively maximal and minimal when they occur within the dry supercritical phase without liquid water. The textural and porosity properties of the cement are weakly affected by all the treatments at 120 C. The porosity even decreases in presence of H{sub 2}S-CO{sub 2}. But these properties are affected at 200 C when liquid water is present in the system. At this temperature, the initial properties are only preserved or improved by the treatments within the dry supercritical phase. The steel is corroded in all cases and thus is the vulnerable material of the wells. (author)

  15. Relationship between carbon dioxide levels and reported headaches on the international space station.

    Science.gov (United States)

    Law, Jennifer; Van Baalen, Mary; Foy, Millennia; Mason, Sara S; Mendez, Claudia; Wear, Mary L; Meyers, Valerie E; Alexander, David

    2014-05-01

    Because of anecdotal reports of CO(2)-related symptoms onboard the International Space Station (ISS), the relationship between CO(2) and in-flight headaches was analyzed. Headache reports and CO(2) measurements were obtained, and arithmetic means and single-point maxima were determined for 24-hour and 7-day periods. Multiple imputation addressed missing data, and logistic regression modeled the relationship between CO(2), headache probability, and covariates. CO(2) level, age at launch, time in-flight, and data source were significantly associated with headache. For each 1-mm Hg increase in CO(2), the odds of a crew member reporting a headache doubled. To keep the risk of headache below 1%, average 7-day CO(2) would need to be maintained below 2.5 mm Hg (current ISS range: 1 to 9 mm Hg). Although headache incidence was not high, results suggest an increased susceptibility to physiological effects of CO(2) in-flight.

  16. Development of spent fuel reprocessing process based on selective sulfurization: Study on the Pu, Np and Am sulfurization

    Science.gov (United States)

    Kirishima, Akira; Amano, Yuuki; Nihei, Toshifumi; Mitsugashira, Toshiaki; Sato, Nobuaki

    2010-03-01

    For the recovery of fissile materials from spent nuclear fuel, we have proposed a novel reprocessing process based on selective sulfurization of fission products (FPs). The key concept of this process is utilization of unique chemical property of carbon disulfide (CS2), i.e., it works as a reductant for U3O8 but works as a sulfurizing agent for minor actinides and lanthanides. Sulfurized FPs and minor actinides (MA) are highly soluble to dilute nitric acid while UO2 and PuO2 are hardly soluble, therefore, FPs and MA can be removed from Uranium and Plutonium matrix by selective dissolution. As a feasibility study of this new concept, the sulfurization behaviours of U, Pu, Np, Am and Eu are investigated in this paper by the thermodynamical calculation, phase analysis of chemical analogue elements and tracer experiments.

  17. Effects of internal mixing and aggregate morphology on optical properties of black carbon using a discrete dipole approximation model

    Directory of Open Access Journals (Sweden)

    B. Scarnato

    2012-10-01

    Full Text Available According to recent studies, internal mixing of black carbon (BC with other aerosol materials in the atmosphere alters its aggregate shape, absorption of solar radiation, and radiative forcing. These mixing state effects are not yet fully understood. In this study, we characterize the morphology and mixing state of bare BC and BC internally mixed with sodium chloride (NaCl using electron microscopy and examine the sensitivity of optical properties to BC mixing state and aggregate morphology using a discrete dipole approximation model (DDSCAT. DDSCAT predicts a higher mass absorption coefficient, lower single scattering albedo (SSA, and higher absorption Angstrom exponent (AAE for bare BC aggregates that are lacy rather than compact. Predicted values of SSA at 550 nm range between 0.18 and 0.27 for lacy and compact aggregates, respectively, in agreement with reported experimental values of 0.25 ± 0.05. The variation in absorption with wavelength does not adhere precisely to a power law relationship over the 200 to 1000 nm range. Consequently, AAE values depend on the wavelength region over which they are computed. In the 300 to 550 nm range, AAE values ranged in this study from 0.70 for compact to 0.95 for lacy aggregates. The SSA of BC internally mixed with NaCl (100–300 nm in radius is higher than for bare BC and increases with the embedding in the NaCl. Internally mixed BC SSA values decrease in the 200–400 nm wavelength range, a feature also common to the optical properties of dust and organics. Linear polarization features are also predicted in DDSCAT and are dependent on particle morphology. The bare BC (with a radius of 80 nm presents in the linear polarization a bell shape feature, which is a characteristic of the Rayleigh regime (for particles smaller than the wavelength of incident radiation. When BC is internally mixed with NaCl (100–300 nm in radius, strong depolarization features for near-VIS incident radiation are evident

  18. Stable cycling of a scalable graphene-encapsulated nanocomposite for lithium-sulfur batteries.

    Science.gov (United States)

    He, Guang; Hart, Connor J; Liang, Xiao; Garsuch, Arnd; Nazar, Linda F

    2014-07-23

    We report the synthesis of a low-cost carbon/sulfur nanocomposite using Ketjen black (KBC) as the carbon framework, encapsulated by thin graphene sheets using a simple process that relies on binding a functionalized KBC/S nanoparticle surface with graphene oxide (GO), which is reduced in situ. A slight excess of GO is employed to create a second layer of graphene wrapping around the KBC/S. This g-KBC/S sulfur cathode exhibits excellent cyclability over 200 cycles where the average stabilized fade rate is only 0.026% or 1.1 mAh g(-1) per cycle. This excellent performance is primarily attributed to the wrapped, internally porous architecture. The large pore volume, small pore diameter, and uniform nanoparticle size of the mesoporous KBC array provides an ideal frame for the fabrication of a homogeneous C/S composite, whereas the graphene/GO sheets serve as an external chemical and physical barrier that inhibits polysulfide diffusion.

  19. Accidents with sulfuric acid

    OpenAIRE

    Rajković Miloš B.

    2006-01-01

    Sulfuric acid is an important industrial and strategic raw material, the production of which is developing on all continents, in many factories in the world and with an annual production of over 160 million tons. On the other hand, the production, transport and usage are very dangerous and demand measures of precaution because the consequences could be catastrophic, and not only at the local level where the accident would happen. Accidents that have been publicly recorded during the last eigh...

  20. Internalizing carbon costs in electricity markets. Using certificates in a load-based emissions trading scheme

    Energy Technology Data Exchange (ETDEWEB)

    Gillenwater, Michael [Science, Technology and Environmental Policy Program, Woodrow Wilson School of Public and International Affairs, Robertson Hall, Princeton University, Princeton, NJ 08540 (United States); Breidenich, Clare [Independent consultant, Seattle, WA (United States)

    2009-01-15

    Several western states have considered developing a regulatory approach to reduce greenhouse gas (GHG) emissions from the electric power industry, referred to as a load-based (LB) cap-and-trade scheme. A LB approach differs from the traditional source-based (SB) cap-and-trade approach in that the emission reduction obligation is placed upon Load Serving Entities (LSEs), rather than electric generators. The LB approach can potentially reduce the problem of emissions leakage, relative to a SB system. For any of these proposed LB schemes to be effective, they must be compatible with modern, and increasingly competitive, wholesale electricity markets. LSE's are unlikely to know the emissions associated with their power purchases. Therefore, a key challenge for a LB scheme is how to assign emissions to each LSE. This paper discusses the problems with one model for assigning emissions under a LB scheme and proposes an alternative, using unbundled Generation Emission Attribute Certificates. By providing a mechanism to internalize an emissions price signal at the generator dispatch level, the tradable certificate model addresses both these problems and provides incentives identical to a SB scheme. (author)

  1. Internalizing carbon costs in electricity markets: Using certificates in a load-based emissions trading scheme

    Energy Technology Data Exchange (ETDEWEB)

    Gillenwater, Michael [Science, Technology and Environmental Policy Program, Woodrow Wilson School of Public and International Affairs, Robertson Hall, Princeton University, Princeton, NJ 08540 (United States)], E-mail: gillenwater@alum.mit.edu; Breidenich, Clare [Independent consultant, Seattle, WA (United States)], E-mail: cbreidenich@yahoo.com

    2009-01-15

    Several western states have considered developing a regulatory approach to reduce greenhouse gas (GHG) emissions from the electric power industry, referred to as a load-based (LB) cap-and-trade scheme. A LB approach differs from the traditional source-based (SB) cap-and-trade approach in that the emission reduction obligation is placed upon Load Serving Entities (LSEs), rather than electric generators. The LB approach can potentially reduce the problem of emissions leakage, relative to a SB system. For any of these proposed LB schemes to be effective, they must be compatible with modern, and increasingly competitive, wholesale electricity markets. LSE's are unlikely to know the emissions associated with their power purchases. Therefore, a key challenge for a LB scheme is how to assign emissions to each LSE. This paper discusses the problems with one model for assigning emissions under a LB scheme and proposes an alternative, using unbundled Generation Emission Attribute Certificates. By providing a mechanism to internalize an emissions price signal at the generator dispatch level, the tradable certificate model addresses both these problems and provides incentives identical to a SB scheme.

  2. Adsorption and destruction of PCDD/Fs using surface-functionalized activated carbons.

    Science.gov (United States)

    Atkinson, J D; Hung, P C; Zhang, Z; Chang, M B; Yan, Z; Rood, M J

    2015-01-01

    Activated carbon adsorbs polychlorinated dibenzo-p-dioxins and -furans (PCDD/Fs) from gas streams but can simultaneously generate PCDD/Fs via de novo synthesis, increasing an already serious disposal problem for the spent sorbent. To increase activated carbon's PCDD/F sorption capacity and lifetime while reducing the impact of hazardous waste, it is beneficial to develop carbon-based sorbents that simultaneously destroy PCDD/Fs while adsorbing the toxic chemicals from gas streams. In this work, hydrogen-treated and surface-functionalized (i.e., oxygen, bromine, nitrogen, and sulfur) activated carbons are tested in a bench-scale reactor as adsorbents for PCDD/Fs. All tested carbons adsorb PCDD/F efficiently, with international toxic equivalent removal efficiencies exceeding 99% and mass removal efficiencies exceeding 98% for all but one tested material. Hydrogen-treated materials caused negligible destruction and possible generation of PCDD/Fs, with total mass balances between 100% and 107%. All tested surface-functionalized carbons, regardless of functionality, destroyed PCDD/Fs, with total mass balances between 73% and 96%. Free radicals on the carbon surface provided by different functional groups may contribute to PCDD/F destruction, as has been hypothesized in the literature. Surface-functionalized materials preferentially destroyed higher-order (more chlorine) congeners, supporting a dechlorination mechanism as opposed to oxidation. Carbons impregnated with sulfur are particularly effective at destroying PCDD/Fs, with destruction efficiency improving with increasing sulfur content to as high as 27%. This is relevant because sulfur-treated carbons are used for mercury adsorption, increasing the possibility of multi-pollutant control.

  3. Reduced graphene oxide film as a shuttle-inhibiting interlayer in a lithium-sulfur battery

    Science.gov (United States)

    Wang, Xuefeng; Wang, Zhaoxiang; Chen, Liquan

    2013-11-01

    A reduced graphene oxide (rGO) based film is sandwiched between a sulfur cathode and the separator, acting as a shuttle inhibitor to the sulfur and polysulfides. The lithium-sulfur cell with such a configuration shows an initial discharge capacity of 1260 mAh g-1 and the capacity remains at 895 mAh g-1 after 100 cycles. The excellent electrochemical performance of the cell is attributed to both the functional groups on the rGO sheets that anchor the sulfur and polysulfides and the carbon additive that helps to produce channels for the electrolyte and polysulfide to enter.

  4. International comparison CCQM-K84—carbon monoxide in synthetic air at ambient level

    Science.gov (United States)

    Lee, Jeongsoon; Moon, Dongmin; Lee, Jinbok; Lim, Jeongsik; Hall, Brad; Novelli, Paul; Brewer, Paul J.; Miller, Michael; Murugun, Arul; Doval Minarro, Marta; Qiao, Han; Shuguo, Hu; Konopelko, L. A.; Kustikov, Y. A.; Kolobova, A. V.; Pankratov, V. V.; Wasserman, I. I.; Zav'yalov, S. V.; Efremova, O. V.; Pavlov, M. V.; Mitchell, Gerald; Guenther, Frank; Walden, Jari; Aoki, Nobuyuki; Shimosaka, Takuya; Tatiana, Mace; Lagler, F.; Borowiak, Annette

    2017-01-01

    Carbon monoxide (CO) is reported to mainly be emitted from industries, transportation, and burnings for various usages. Its atmospheric lifetime varies from weeks to months, depending on the mixing ratio of the highly reactive hydroxyl radical. Even though the ambient level of CO varies as a function of regional sources, the mixing ratio ranges from 30 nmol/mol to 300 nmol/mol at the marine boundary layers and from 100 nmol/mol to more than 500 nmol/mol in urban areas(1). In order to study temporal trends and regional variations of the level of CO, the National Oceanic & Atmospheric Administration/Earth System Research Laboratory-Global Monitoring Division (NOAA/ESRL-GMD(2)) has played a key role as the designated Central Calibration Laboratory (CCL) within the frame of the World Meteorological Organization (WMO) Global Atmosphere Watch (GAW) program. NOAA/ESRL-GMD provides natural air standards, analyzed for CO, to WMO GAW participants. Since the structure of WMO traceability chain appears hierarchical and explicit all over the world, WMO intends to improve the CO measurement compatibility to up to 2 ppb (in case of extensive compatibility goal: 5 ppb, GAW report No. 213(3)) in order to ensure compatibility through the GAW network. Nevertheless, accurate measurement of CO at an ambient level has proven to be difficult due to the lack of stability in cylinders. For these reasons, it is necessary that measured results are compared among the values assigned by various NMIs. This key comparison was initially proposed to be aimed at a CO/N2 standard in the 2010 CCQM meeting by KRISS. With participation of FMI, NOAA, and Empa, a modified scheme of CO/air standards was developed for the purpose of atmospheric observations and co-operative support to WMO/GAW activities. Therefore, the purpose of the comparison is to support the measurement capability of CO at an ambient level of 350 nmol/mol. Further, this key comparison is expected to contribute to the establishment of

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

    Science.gov (United States)

    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.

  6. Sodium and sulfur release and recapture during black liquor burning

    Energy Technology Data Exchange (ETDEWEB)

    Frederick, W.J.; Iisa, K.; Wag, K.; Reis, V.V.; Boonsongsup, L.; Forssen, M.; Hupa, M.

    1995-08-01

    The objective of this study was to provide data on sulfur and sodium volatilization during black liquor burning, and on SO2 capture by solid sodium carbonate and sodium chloride. This data was interpreted and modeled into rate equations suitable for use in computational models for recovery boilers.

  7. Beam-foil spectra of the highly ionized sulfur

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Spectra of carbon, boron, beryllium, lithium, belium and hydrongen-line for sulfur obtained at an energy of 80 MeV, wherein thirty-four lines have been identified. Analysis of the spectra was based on theoretical results and other experimental data.

  8. A graphitic hollow carbon nitride nanosphere as a novel photochemical internalization agent for targeted and stimuli-responsive cancer therapy

    Science.gov (United States)

    Liu, Chaoqun; Chen, Zhaowei; Wang, Zhenzhen; Li, Wei; Ju, Enguo; Yan, Zhengqing; Liu, Zhen; Ren, Jinsong; Qu, Xiaogang

    2016-06-01

    As a novel technique, photochemical internalization (PCI) has been employed as a new approach to overcome endo/lysosomal restriction, which is one of the main difficulties in both drug and gene delivery. However, the complicated synthesis procedure (usually requiring the self-assembly of polymers, photosensitizers and cargos) and payload specificity greatly limit its further application. In this paper, we employ a highly fluorescent graphitic hollow carbon nitride nanosphere (GHCNS) to simultaneously serve as a PCI photosensitizer, an imaging agent and a drug carrier. The surface modification of GHCNS with multifunctional polysaccharide hyaluronic acid (HA) endows the system with colloidal stability, biocompatibility and cancer cell targeting ability. After CD44 receptor-mediated endocytosis, the nanosystem is embedded in endo/lysosomal vesicles and HA could be specially degraded by hyaluronidase (Hyal), inducing open pores. In the following, with visible light illumination, GHCNS could produce ROS that effectively induced lipid peroxidation and caused endo/lysosomal membrane break, accelerating the cytoplasmic release of the drug in the targeted and irradiated cells. As a result, significantly increased therapeutic potency and specificity against cancer cells could be achieved.As a novel technique, photochemical internalization (PCI) has been employed as a new approach to overcome endo/lysosomal restriction, which is one of the main difficulties in both drug and gene delivery. However, the complicated synthesis procedure (usually requiring the self-assembly of polymers, photosensitizers and cargos) and payload specificity greatly limit its further application. In this paper, we employ a highly fluorescent graphitic hollow carbon nitride nanosphere (GHCNS) to simultaneously serve as a PCI photosensitizer, an imaging agent and a drug carrier. The surface modification of GHCNS with multifunctional polysaccharide hyaluronic acid (HA) endows the system with colloidal

  9. Removal of Sulfur from Natural Gas to Reduce Particulate Matter Emission from a Turbine Engine

    Science.gov (United States)

    Spang, Brent Loren

    The present work investigates the effect of natural gas fuel sulfur on particulate emissions from stationary gas turbine engines used for electricity generation. Fuel sulfur from standard line gas was scrubbed using a system of fluidized reactor beds containing a specially designed activated carbon purpose built for sulfur absorption. A sulfur injection system using sonic orifices was designed and constructed to inject methyl mercaptan into the scrubbed gas stream at varying concentrations. Using these systems, particulate emissions created by various fuel sulfur levels between 0 and 8.3 ppmv were investigated. Particulate samples were collected from a Capstone C65 microturbine generator system using a Horiba MDLT-1302TA micro dilution tunnel and analyzed using a Horiba MEXA-1370PM particulate analyzer. In addition, ambient air samples were collected to determine incoming particulate levels in the combustion air. The Capstone C65 engine air filter was also tested for particulate removal efficiency by sampling downstream of the filter. To further differentiate the particulate entering the engine in the combustion air from particulate being emitted from the exhaust stack, two high efficiency HEPA filters were installed to eliminate a large portion of incoming particulate. Variable fuel sulfur testing showed that there was a strong correlation between total particulate emission factor and fuel sulfur concentration. Using eleven variable sulfur tests, it was determined that an increase of 1 ppmv fuel sulfur will produce an increase of approximately 3.2 microg/m3 total particulate. Also, the correlation also predicted that, for this particular engine, the total particulate emission factor for zero fuel sulfur was approximately 19.1 microg/m3. With the EC and OC data removed, the correlation became 3.1 microg/m3 of sulfur particulate produced for each ppmv of fuel sulfur. The correlation also predicted that with no fuel sulfur present, 6.6 microg/m3 of particulate will

  10. Effects of freeze drying and silver staining on carbonization of cellulose: carbon nano-materials

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dae-Young; Im, Hyun Sik [Dongguk University, Seoul (Korea, Republic of)

    2012-05-15

    We investigated the effects of sulfuric acid and silver particles on the carbonization of natural cellulose from Halocynthia. We carried out thermogravimetry and used transmission electron microscopy measurements to study the yield of carbon and the structure of the carbonized nano-fiber. We found that the addition of sulfuric acid and silver particles to the cellulose fiber enhanced the yield of carbon while keeping the original structure of the carbon nano-fiber.

  11. Loss of proliferation and antigen presentation activity following internalization of polydispersed carbon nanotubes by primary lung epithelial cells.

    Directory of Open Access Journals (Sweden)

    Mandavi Kumari

    Full Text Available Interactions between poly-dispersed acid functionalized single walled carbon nanotubes (AF-SWCNTs and primary lung epithelial (PLE cells were studied. Peritoneal macrophages (PMs, kn