WorldWideScience

Sample records for californium sulfides

  1. Magnetism in californium

    International Nuclear Information System (INIS)

    A SQUID-based magnetic susceptometer has been constructed for studying small radioactive samples at temperatures below 350 K and in magnetic fields up to 50 kilogauss. The device has been used to study californium (element 98) in a number of solid-state forms: the dhcp metal, several oxides (Cf2O3 in both the bcc and monoclinic structures, Cf7O12, CfO2 and BaCfO3), several monopnictides (CfN, CfAs and CfSb) and the trichloride (in both the hexagonal and orthorhombic structures). All of these materials were studied in polycrystalline form, and hexagonal CfCl3 was studied in single-crystal form as well. The susceptometer has the sensitivity to measure samples containing less than 10 micrograms of californium. The magnetic susceptibilities of all of the californium materials at temperatures above about 100 K are described well by the Curie-Weiss relationship. This behavior is consistent with the assumption that the magnetic 5f electrons are localized and that the paramagnetic behavior can be interpreted in terms of the properties of the free ion. The measured values of the effective paramagnetic moment, μ/sub eff/, for all the californium materials that were studied are reasonably consistent with theoretical values based on intermediate coupling models. All of the californium materials showed some indications of cooperative magnetic effects. The dhcp metal was observed to order ferromagnetically at 52 K, and all of the californium compounds studied showed signs of antiferromagnetic ordering, mostly at temperatures below 25 K. 91 refs., 50 figs., 19 tabs

  2. Californium Multiplier (CFX)

    International Nuclear Information System (INIS)

    The availability of 252Cf as an economical high-intensity neutron source has made it possible to construct compact neutron irradiation devices with widespread applications. The simplest such device consists of a single 252Cf source within a moderating and shielding medium. Higher neutron flux levels can be attained either through the use of more 252Cf or through source multiplication by means of a subcritical uranium assembly. Although the use of larger 252Cf sources to achieve higher neutron flux is technically straightforward, an economic penalty is paid as the source strength is increased. Larger californium sources imply larger initial investments to cover the cost of source material and larger operating costs resulting from the decay of the 252Cf source. A Californium Multiplier, the CFX, which produces a flux enhancement of 30 when compared to a conventional moderated 252Cf system has been designed, licensed, built, and tested by IRT Corporation. Such systems are now available on a commercial basis for both neutron radiography and neutron activation analysis. The first commercial CFX system was installed at the Research Laboratories of Eastman Kodak Company in Rochester, NY, in March 1975. This device, using 1 mg of 252Cf, is very stable and the neutron flux generated by the CFX is very reproducible. The performance characteristics of this system are summarized

  3. Californium--palladium metal neutron source material

    Science.gov (United States)

    Dahlen, B.L.; Mosly, W.C. Jr.; Smith, P.K.; Albenesius, E.L.

    1974-01-22

    Californium, as metal or oxide, is uniformly dispersed throughout a noble metal matrix, provided in compact, rod or wire form. A solution of californium values is added to palladium metal powder, dried, blended and pressed into a compact having a uni-form distribution of californium. The californium values are decomposed to californium oxide or metal by heating in an inert or reducing atmosphere. Sintering the compact to a high density closes the matrix around the dispersed californium. The sintered compact is then mechanically shaped into an elongated rod or wire form. (4 claims, no drawings) (Official Gazette)

  4. Californium-252 progress, report No. 7, April 1971

    Energy Technology Data Exchange (ETDEWEB)

    1971-12-31

    This report contains discusses of the following topics on Californium-252: First sales of californium-252; encapsulation services discussed; three new participants in market evaluation program; summer training programs to use californium; Californium-252 shipping casks available; Californium-252 questions and answers, radiotherapy; neutron radiography; natural resources exploration; nuclear safeguards; process control; dosimetry; neutron radiography; neutron shielding; and nuclear safeguards.

  5. Californium Electrodepositions at Oak Ridge National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Boll, Rose Ann [ORNL

    2015-01-01

    Electrodepositions of californium isotopes were successfully performed at Oak Ridge National Laboratory (ORNL) during the past year involving two different types of deposition solutions, ammonium acetate (NH4C2H3O2) and isobutanol ((CH3)2CHCH2OH). A californium product that was decay enriched in 251Cf was recovered for use in super-heavy element (SHE) research. This neutron-rich isotope, 251Cf, provides target material for SHE research for the potential discovery of heavier isotopes of Z=118. The californium material was recovered from aged 252Cf neutron sources in storage at ORNL. These sources have decayed for over 30 years, thus providing material with a very high 251Cf-to-252Cf ratio. After the source capsules were opened, the californium was purified and then electrodeposited using the isobutanol method onto thin titanium foils for use in an accelerator at the Joint Institute for Nuclear Research in Dubna, Russia. Another deposition method, ammonium acetate, was used to produce a deposition containing 1.7 0.1 Ci of 252Cf onto a stainless steel substrate. This was the largest single electrodeposition of 252Cf ever prepared. The 252Cf material was initially purified using traditional ion exchange media, such as AG50-AHIB and AG50-HCl, and further purified using a TEVA-NH4SCN system to remove any lanthanides, resulting in the recovery of 3.6 0.1 mg of purified 252Cf. The ammonium acetate deposition was run with a current of 1.0 amp, resulting in a 91.5% deposition yield. Purification and handling of the highly radioactive californium material created additional challenges in the production of these sources.

  6. Historical Review of Californium-252 Discovery and Development

    Science.gov (United States)

    Stoddard, D. H.

    1985-01-01

    This paper discusses the discovery and history of californium 252. This isotope may be synthesized by irradiating plutonium 239, plutonium 242, americium 243, or curium 244 with neutrons in a nuclear reactor. Various experiments and inventions involving Cf conducted at the Savannah River Plant are discussed. The evolution of radiotherapy using californium 252 is reviewed. (PLG)

  7. Historical review of californium-252 discovery and development

    International Nuclear Information System (INIS)

    This paper discusses the discovery and history of californium 252. This isotope may be synthesized by irradiating plutonium 239, plutonium 242, americium 243, or curium 244 with neutrons in a nuclear reactor. Various experiments and inventions involving 252Cf conducted at the Savannah River Plant are discussed. The evolution of radiotherapy using californium 252 is reviewed

  8. Californium-252: a remarkable versatile radioisotope

    Energy Technology Data Exchange (ETDEWEB)

    Osborne-Lee, I.W.; Alexander, C.W.

    1995-10-10

    A product of the nuclear age, Californium-252 ({sup 252}Cf) has found many applications in medicine, scientific research, industry, and nuclear science education. Californium-252 is unique as a neutron source in that it provides a highly concentrated flux and extremely reliable neutron spectrum from a very small assembly. During the past 40 years, {sup 252}Cf has been applied with great success to cancer therapy, neutron radiography of objects ranging from flowers to entire aircraft, startup sources for nuclear reactors, fission activation for quality analysis of all commercial nuclear fuel, and many other beneficial uses, some of which are now ready for further growth. Californium-252 is produced in the High Flux Isotope Reactor (HFIR) and processed in the Radiochemical Engineering Development Center (REDC), both of which are located at the Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee. The REDC/HFIR facility is virtually the sole supplier of {sup 252}Cf in the western world and is the major supplier worldwide. Extensive exploitation of this product was made possible through the {sup 252}Cf Market Evaluation Program, sponsored by the United States Department of Energy (DOE) [then the Atomic Energy Commission (AEC) and later the Energy Research and Development Administration (ERDA)]. This program included training series, demonstration centers, seminars, and a liberal loan policy for fabricated sources. The Market Evaluation Program was instituted, in part, to determine if large-quantity production capability was required at the Savannah River Laboratory (SRL). Because of the nature of the product and the means by which it is produced, {sup 252}Cf can be produced only in government-owned facilities. It is evident at this time that the Oak Ridge research facility can meet present and projected near-term requirements. The production, shipment, and sales history of {sup 252}Cf from ORNL is summarized herein.

  9. Californium-252: a remarkable versatile radioisotope

    International Nuclear Information System (INIS)

    A product of the nuclear age, Californium-252 (252Cf) has found many applications in medicine, scientific research, industry, and nuclear science education. Californium-252 is unique as a neutron source in that it provides a highly concentrated flux and extremely reliable neutron spectrum from a very small assembly. During the past 40 years, 252Cf has been applied with great success to cancer therapy, neutron radiography of objects ranging from flowers to entire aircraft, startup sources for nuclear reactors, fission activation for quality analysis of all commercial nuclear fuel, and many other beneficial uses, some of which are now ready for further growth. Californium-252 is produced in the High Flux Isotope Reactor (HFIR) and processed in the Radiochemical Engineering Development Center (REDC), both of which are located at the Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee. The REDC/HFIR facility is virtually the sole supplier of 252Cf in the western world and is the major supplier worldwide. Extensive exploitation of this product was made possible through the 252Cf Market Evaluation Program, sponsored by the United States Department of Energy (DOE) [then the Atomic Energy Commission (AEC) and later the Energy Research and Development Administration (ERDA)]. This program included training series, demonstration centers, seminars, and a liberal loan policy for fabricated sources. The Market Evaluation Program was instituted, in part, to determine if large-quantity production capability was required at the Savannah River Laboratory (SRL). Because of the nature of the product and the means by which it is produced, 252Cf can be produced only in government-owned facilities. It is evident at this time that the Oak Ridge research facility can meet present and projected near-term requirements. The production, shipment, and sales history of 252Cf from ORNL is summarized herein

  10. Californium-252 Neutron Therapy in China

    International Nuclear Information System (INIS)

    Californium-252 brachytherapy, believed to be the most successful source for neutron therapy, gives most of the cures as well as long-term and complication-free survivals. Chinese radiation oncologists were interested in californium neutron therapy (Cf-NT) in the early 1980s, but 252Cf sources for medical use were not available in China until 1992 when a californium joint venture was established by the China Institute of Atomic Energy (Beijing) and the Research Institute for Nuclear Reactors (Dimitrovgrad) of Russia. In 1995, 25 seeds of 252Cf with a strength of 3 μg each were sent to China for preclinical investigation. Three years later, a high dose rate (HDR) 252Cf source was imported and transferred into a home-made remote after-loader for intracavitary treatment in Chongqing, and a clinical trail was started in February 1999. This is the first time that Cf-NT was performed for cancer patients in China. Since then, Cf-NT in China has developed rapidly. It is estimated that one-tenth of those radiation oncology centers with brachytherapy practice will be equipped with californium units in 5 yr. That means more than 30 units will be in use in hospitals. That is significant compared with other countries, but it is just one, on average, for each province or one per 40 million people in China. Progress also has been achieved in the 252Cf treatment delivery equipment. Preliminary clinical trails showed complete response observed in all cases treated, with a rapid clearance of tumors and mild reactions in normal tissues. The short-term results are quite encouraging. To deal with problems due to the demand for Cf-NT in China, attention should be paid to the following particulars: (1) A high-strength miniature source is needed for HDR/MDR interstitial therapy to extend the Cf-NT coverage. (2) Basic work on radiophysics and radiobiology needs to be done, including source calibration, clinical dosimetry, clinical RBE determination, and Cf-NT quality assurance

  11. Californium-252 sales and loans at Oak Ridge National Laboratory

    International Nuclear Information System (INIS)

    The production and distribution in the United States of 252Cf has recently been consolidated at the Oak Ridge National Laboratory (ORNL). The 252Cf Industrial Sales/Loan Program and the 252Cf University Load Program, which were formerly located at the Savannah River Plant (SRP), have been combined with the californium production and distribution activities of the Transuranium Element Production Program at ORNL. Californium-252 is sold to commercial users in the form of bulk californium oxide, palladium-californium alloy pellets, or alloy wires. Neutron source capsules, which are fabricated for loans to DOE or other US government agencies, are still available in all forms previously available. The consolidation of all 252Cf distribution activities at the production site is expected to result in better service to users. In particular, customers for neutrons sources will be ale to select from a wider range of neutron source forms, including custom designs, through a single contact point

  12. Californium-252 encapsulation at the Savannah River Laboratory

    International Nuclear Information System (INIS)

    More than 1 g of the neutron-emitting isotope californium-252 has been encapsulated at SRL for worldwide medical, industrial, and research uses. Bulk sales packages have been prepared for the USDOE sales program since 1971. Doubly-encapsulated sources have been prepared for USDOE's market evaluation program since 1968. Californium-252 sources for loan and sales packages satisfy the criteria for Special Form Radioactive Material. Encapsulation is performed in special neutron-shielded containment facilities at SRL. Development of improved source and shipping package designs and processes is continuing. 17 figures

  13. Selenium Sulfide

    Science.gov (United States)

    Selenium sulfide, an anti-infective agent, relieves itching and flaking of the scalp and removes the dry, scaly particles ... Selenium sulfide comes in a lotion and is usually applied as a shampoo. As a shampoo, selenium sulfide usually ...

  14. Production, distribution and applications of californium-252 neutron sources

    International Nuclear Information System (INIS)

    The radioisotope 252Cf is routinely encapsulated into compact, portable, intense neutron sources with a 2.6-yr half-life. A source the size of a person's little finger can emit up to 1011 neutrons s-1. Californium-252 is used commercially as a reliable, cost-effective neutron source for prompt gamma neutron activation analysis (PGNAA) of coal, cement and minerals, as well as for detection and identification of explosives, land mines and unexploded military ordnance. Other uses are neutron radiography, nuclear waste assays, reactor start-up sources, calibration standards and cancer therapy. The inherent safety of source encapsulations is demonstrated by 30 yr of experience and by US Bureau of Mines tests of source survivability during explosions. The production and distribution center for the US Department of Energy (DOE) Californium Program is the Radiochemical Engineering Development Center (REDC) at Oak Ridge National Laboratory (ORNL). DOE sells 252Cf to commercial reencapsulators domestically and internationally. Sealed 252Cf sources are also available for loan to agencies and subcontractors of the US government and to universities for educational, research and medical applications. The REDC has established the Californium User Facility (CUF) for Neutron Science to make its large inventory of 252Cf sources available to researchers for irradiations inside uncontaminated hot cells. Experiments at the CUF include a land mine detection system, neutron damage testing of solid-state detectors, irradiation of human cancer cells for boron neutron capture therapy experiments and irradiation of rice to induce genetic mutations

  15. Production, distribution and applications of californium-252 neutron sources.

    Science.gov (United States)

    Martin, R C; Knauer, J B; Balo, P A

    2000-01-01

    The radioisotope 252Cf is routinely encapsulated into compact, portable, intense neutron sources with a 2.6-yr half-life. A source the size of a person's little finger can emit up to 10(11) neutrons s(-1). Californium-252 is used commercially as a reliable, cost-effective neutron source for prompt gamma neutron activation analysis (PGNAA) of coal, cement and minerals, as well as for detection and identification of explosives, land mines and unexploded military ordinance. Other uses are neutron radiography, nuclear waste assays, reactor start-up sources, calibration standards and cancer therapy. The inherent safety of source encapsulations is demonstrated by 30 yr of experience and by US Bureau of Mines tests of source survivability during explosions. The production and distribution center for the US Department of Energy (DOE) Californium Program is the Radiochemical Engineering Development Center (REDC) at Oak Ridge National Laboratory (ORNL). DOE sells 252Cf to commercial reencapsulators domestically and internationally. Sealed 252Cf sources are also available for loan to agencies and subcontractors of the US government and to universities for educational, research and medical applications. The REDC has established the Californium User Facility (CUF) for Neutron Science to make its large inventory of 252Cf sources available to researchers for irradiations inside uncontaminated hot cells. Experiments at the CUF include a land mine detection system, neutron damage testing of solid-state detectors, irradiation of human cancer cells for boron neutron capture therapy experiments and irradiation of rice to induce genetic mutations. PMID:11003521

  16. Production, Distribution, and Applications of Californium-252 Neutron Sources

    Energy Technology Data Exchange (ETDEWEB)

    Balo, P.A.; Knauer, J.B.; Martin, R.C.

    1999-10-03

    The radioisotope {sup 252}Cf is routinely encapsulated into compact, portable, intense neutron sources with a 2.6-year half-life. A source the size of a person's little finger can emit up to 10{sup 11} neutrons/s. Californium-252 is used commercially as a reliable, cost-effective neutron source for prompt gamma neutron activation analysis (PGNAA) of coal, cement, and minerals, as well as for detection and identification of explosives, laud mines, and unexploded military ordnance. Other uses are neutron radiography, nuclear waste assays, reactor start-up sources, calibration standards, and cancer therapy. The inherent safety of source encapsulations is demonstrated by 30 years of experience and by U.S. Bureau of Mines tests of source survivability during explosions. The production and distribution center for the U. S Department of Energy (DOE) Californium Program is the Radiochemical Engineering Development Center (REDC) at Oak Ridge National Laboratory (ORNL). DOE sells The radioisotope {sup 252}Cf is routinely encapsulated into compact, portable, intense neutron sources with a 2.6- year half-life. A source the size of a person's little finger can emit up to 10 neutrons/s. Californium-252 is used commercially as a reliable, cost-effective neutron source for prompt gamma neutron activation analysis (PGNAA) of coal, cement, and minerals, as well as for detection and identification of explosives, laud mines, and unexploded military ordnance. Other uses are neutron radiography, nuclear waste assays, reactor start-up sources, calibration standards, and cancer therapy. The inherent safety of source encapsulations is demonstrated by 30 years of experience and by U.S. Bureau of Mines tests of source survivability during explosions. The production and distribution center for the U. S Department of Energy (DOE) Californium Program is the Radiochemical Engineering Development Center (REDC) at Oak Ridge National Laboratory(ORNL). DOE sells {sup 252}Cf to commercial

  17. Production of extra pure curium and californium preparations

    International Nuclear Information System (INIS)

    Preparations of curium-244,245,248 and californium-249,252 are used for the production of ionizing radiation sources for different applications and fundamental nuclear-physical investigations, placing high requirements on the radiochemical and chemical purity of the preparations. Extraction chromatography using di-(2-ethylhexyl)phosphoric acid (D2EHPA) as extractant was chosen to prepare extra pure curium and californium preparations. In order to identify the optimal conditions of Cm-Cf separation and to remove impurities from them (reagent and other impurities), investigations were performed into the effect of impurities (Na+, Ca2+, Al3+, Fe2+, Fe3+ taken as example), extractant and eluent concentration and solution flow rate on the efficiency of mutual purification of Cm and Cf. Both theoretical and experimental estimations were made of the maximum concentration at which the impurities do not affect the process. The conditions chosen allow mutual purification of milligram amounts of Cm and Cf from impurity elements at E(pur) =102 - 103 during a single chromatographic cycle (E(pur) =>103) using a column with 5 - 10 cm3 volume. In this case the production yield exceeds 98%. The purification of milligram amounts of curium and californium from fission products (lanthanides in general, cerium in particular) was performed in D2EHPA-decane-PbO2-HNO3 and D2EHPA-decane-DTPA-H3-Cit extraction chromatography systems. In order to establish the optimal conditions, the effect of [D2EHPA] and eluent on the mutual purification of Cm and Cf and on their purification from cerium and impurity elements was studied in the D2EHPA-decane-PbO2-HNO3 system. During a single chromatographic cycle the mutual purification factors of TPE and of their purification from impurity cations achieve 102-103, from cerium - E(pur) > 10. In the D2EHPA-decane-DTPA-H3Cit system, the effect of concentration of extractant and eluent pH on the efficiency of Cm and Cf purification from lanthanides was

  18. Prompt neutron spectrum of the spontaneous fission of californium-252

    International Nuclear Information System (INIS)

    The californium-252 spontaneous fission neutron spectrum was measured in the energy range of 0.01 to 10 MeV by the time-of-flight technique using various neutron detectors. The measurements of 252Cf neutron spectrum at energies of 0.01 to 5 MeV were performed as a function of fission fragment kinetic energy. The mean neutron spectrum energy in the range of 0.7 to 10 MeV was found from the results of measurements. The irregularity in the 252Cf neutron spectrum in the neutron energy range of less than 0.7 MeV compared to theoretical values is discussed. The mechanism of 252Cf neutron emission is also discussed on the basis of neutron yield angle measurements. 12 references

  19. Separation of californium from actinides and lanthanides in aqueous solution by electrochemical formation of amalgams

    International Nuclear Information System (INIS)

    The electrochemical reduction of transneptunium elements (Pu to Cf) and rare earths (Eu, Tm) from aqueous complexing solutions to amalgams was studied over a wide range of cathodic potentials in order to achieve optimal separation of californium. The reduction in acetate media (pH 4.5-4.6) at potentials around -1.7 to -1.9 V1 leads to a quantitative extraction of californium into the mercury phase, while more negative potentials are required for the reduction of the lighter transuranium elements and of the lanthanides. Hence, the optimal conditions for the separation of californium from the investigated actinides and lanthanides were determined. Separation factors α between 25 and 90 were found except in the case of Cf/Eu, where poor values (α varying from 7 to 12) were observed. More negative cathodic potentials decrease the selectivity of the reduction process. A similar study with lithium citrate solutions (pH ∝6) shows that satisfactory separation of californium from lighter and heavier actinides is achievable. A separation factor of 88 is obtained for Cf/Am at -1.98 V. The anodic stripping of mixed amalgams (Pu, Am, Cm, Bk, Tm and Cf) Hg in nitric and acetic acid soultions at potentials ranging from +0.1 to -0.7 V proceeds slowly and proved to be ineffective for the separation of californium from light actinides under conditions described. (orig.)

  20. Biomedical neutron research at the Californium User Facility for neutron science

    International Nuclear Information System (INIS)

    The Californium User Facility for Neutron Science has been established at Oak Ridge National Laboratory (ORNL). The Californium User Facility (CUF) is a part of the larger Californium Facility, which fabricates and stores compact 252Cf neutron sources for worldwide distribution. The CUF can provide a cost-effective option for research with 252Cf sources. Three projects at the CUF that demonstrate the versatility of 252Cf for biological and biomedical neutron-based research are described: future establishment of a 252Cf-based neutron activation analysis system, ongoing work to produce miniature high-intensity, remotely afterloaded 252Cf sources for tumor therapy, and a recent experiment that irradiated living human lung cancer cells impregnated with experimental boron compounds to test their effectiveness for boron neutron capture therapy

  1. Biomedical neutron research at the Californium User Facility for neutron science

    Energy Technology Data Exchange (ETDEWEB)

    Martin, R.C. [Oak Ridge National Lab., TN (United States); Byrne, T.E. [Roane State Community College, Harriman, TN (United States); Miller, L.F. [Univ. of Tennessee, Knoxville, TN (United States)

    1997-04-01

    The Californium User Facility for Neutron Science has been established at Oak Ridge National Laboratory (ORNL). The Californium User Facility (CUF) is a part of the larger Californium Facility, which fabricates and stores compact {sup 252}Cf neutron sources for worldwide distribution. The CUF can provide a cost-effective option for research with {sup 252}Cf sources. Three projects at the CUF that demonstrate the versatility of {sup 252}Cf for biological and biomedical neutron-based research are described: future establishment of a {sup 252}Cf-based neutron activation analysis system, ongoing work to produce miniature high-intensity, remotely afterloaded {sup 252}Cf sources for tumor therapy, and a recent experiment that irradiated living human lung cancer cells impregnated with experimental boron compounds to test their effectiveness for boron neutron capture therapy.

  2. Emergence of californium as the second transitional element in the actinide series.

    Science.gov (United States)

    Cary, Samantha K; Vasiliu, Monica; Baumbach, Ryan E; Stritzinger, Jared T; Green, Thomas D; Diefenbach, Kariem; Cross, Justin N; Knappenberger, Kenneth L; Liu, Guokui; Silver, Mark A; DePrince, A Eugene; Polinski, Matthew J; Van Cleve, Shelley M; House, Jane H; Kikugawa, Naoki; Gallagher, Andrew; Arico, Alexandra A; Dixon, David A; Albrecht-Schmitt, Thomas E

    2015-01-01

    A break in periodicity occurs in the actinide series between plutonium and americium as the result of the localization of 5f electrons. The subsequent chemistry of later actinides is thought to closely parallel lanthanides in that bonding is expected to be ionic and complexation should not substantially alter the electronic structure of the metal ions. Here we demonstrate that ligation of californium(III) by a pyridine derivative results in significant deviations in the properties of the resultant complex with respect to that predicted for the free ion. We expand on this by characterizing the americium and curium analogues for comparison, and show that these pronounced effects result from a second transition in periodicity in the actinide series that occurs, in part, because of the stabilization of the divalent oxidation state. The metastability of californium(II) is responsible for many of the unusual properties of californium including the green photoluminescence. PMID:25880116

  3. Fissile analysis of Hanford waste using Californium Multiplier/Delayed Neutron Counter system

    International Nuclear Information System (INIS)

    Measurement of low-level (10 ng/g or lower) fissile material (mainly plutonium) in Hanford waste and process samples is becoming increasingly important. A system has been designed consisting of a Californium Multiplier (CFX) and a Delayed Neutron Counter (DNC) to characterize these samples. This report describes hardware and analytical capability of the CFX/DNC system

  4. Emergence of californium as the second transitional element in the actinide series

    OpenAIRE

    Cary, Samantha K.; Vasiliu, Monica; Baumbach, Ryan E.; Stritzinger, Jared T.; GREEN, THOMAS D.; Diefenbach, Kariem; Cross, Justin N.; Knappenberger, Kenneth L.; Liu, Guokui; Silver, Mark A.; DePrince, A. Eugene; Polinski, Matthew J.; Van Cleve, Shelley M.; House, Jane H.; Kikugawa, Naoki

    2015-01-01

    A break in periodicity occurs in the actinide series between plutonium and americium as the result of the localization of 5f electrons. The subsequent chemistry of later actinides is thought to closely parallel lanthanides in that bonding is expected to be ionic and complexation should not substantially alter the electronic structure of the metal ions. Here we demonstrate that ligation of californium(III) by a pyridine derivative results in significant deviations in the properties of the resu...

  5. Spontaneous Partitioning of Californium from Curium: Curious Cases from the Crystallization of Curium Coordination Complexes

    Energy Technology Data Exchange (ETDEWEB)

    Cary, Samantha K.; Silver, Mark A.; Liu, Guokui; Wang, Jamie C.; Bogart, Justin A.; Stritzinger, Jared T.; Arico, Alexandra A.; Hanson, Kenneth; Schelter, Eric J.; Albrecht-Schmitt, Thomas E.

    2015-12-07

    The reaction of 248CmCl3 with excess 2,6-pyridinedicarboxylic acid (DPA) under mild solvothermal conditions results in crystallization of the tris-chelate complex Cm(HDPA)3·H2O. Approximately half of the curium remains in solution at the end of this process, and evaporation of the mother liquor results in crystallization of the bis-chelate complex [Cm(HDPA)- (H2DPA)(H2O)2Cl]Cl·2H2O. 248Cm is the daughter of the α decay of 252Cf and is extracted in high purity from this parent. However, trace amounts of 249,250,251Cf are still present in all samples of 248Cm. During the crystallization of Cm(HDPA)3·H2O and [Cm(HDPA)(H2DPA)(H2O)2Cl]Cl·2H2O, californium(III) spontaneously separates itself from the curium complexes and is found doped within crystals of DPA in the form of Cf(HDPA)3. These results add to the growing body of evidence that the chemistry of californium is fundamentally different from that of earlier actinides.

  6. Manganese determination om minerals by activation analysis, using the californium-252 as a neutron source

    International Nuclear Information System (INIS)

    Neutron Activation Analysis, using a Californium-252 neutron source, has been applied for the determination of manganese in ores such as pyrolusite, rodonite (manganese silicate)' and blending used in dry-batteries The favorable nuclear properties of manganese, such as high thermal neutron cross-section for the reaction 55Mn (n.gamma)56 Mn, high concentration of manganese in the matrix and short half - life of 56Mn, are an ideal combination for non-destructive analysis of manganese in ores. Samples and standards of manganese dioxide were irradiated for about 20 minutes, followed by a 4 to 15 minutes decay and counted in a single channel pulse-height discrimination using a NaI(Tl) scintillation detector. Counting time was equal to 10 minutes. The interference of nuclear reactions 56Fe(n,p)56Mn and 59 Co (n, α)56 were studied, as well as problems in connection with neutron shadowing during irradiation, gamma-rays attenuation during counting and influence of granulometry of samples. One sample,was also analysed by wet-chemical method (sodium bismuthate) in order to compare results. As a whole, i t was shown that the analytical method of neutron activation for manganese in ores and blending, is a method simple, rapid and with good precision and accuracy. (author)

  7. Long-term effects of an intracavitary treatment with californium-252 on normal tissue

    International Nuclear Information System (INIS)

    About one hundred fifty swine were exposed to either radium-226 or californium-252 sources in the uterine cervix to determine an RBE for both acute and long-term effects. That value for early changes in the tissues at risk in the treatment of cervical cancer was between 6.2 and 6.8. The incidence of complications increased with time after exposure, especially among animals treated with 252Cf. Analysis of rectal injury showed that ulceration occurred frequently within a year postexposure at doses between 1600 and 2400 rad calculated at 2 cm lateral to the source midline. Fat necrosis and smooth muscle atrophy, resulting in a local rectal stricture, were delayed changes observed in some animals. The lower ureter was the site for a greater frequency of complications than the GI tract. Ureteral stricture often occurred at doses of 1200 rad from 252Cf and 7000 rad from 226Ra. Observation of delayed effects in the uterine-cervix in animals held up to 4 years postexposure indicate that the RBE for 252Cf may be increased to a value as high as 18, while repair may have even decreased it to about 5.6 in the rectum. Fifty swine are still being observed for long-term effects after doses above 800 rad from 252Cf and 5000 rad from 226Ra

  8. SULFIDE METHOD PLUTONIUM SEPARATION

    Science.gov (United States)

    Duffield, R.B.

    1958-08-12

    A process is described for the recovery of plutonium from neutron irradiated uranium solutions. Such a solution is first treated with a soluble sullide, causing precipitation of the plutoniunn and uraniunn values present, along with those impurities which form insoluble sulfides. The precipitate is then treated with a solution of carbonate ions, which will dissolve the uranium and plutonium present while the fission product sulfides remain unaffected. After separation from the residue, this solution may then be treated by any of the usual methods, such as formation of a lanthanum fluoride precipitate, to effect separation of plutoniunn from uranium.

  9. Sulfide oxidation in a biofilter

    DEFF Research Database (Denmark)

    Pedersen, Claus Lunde; Liu, Dezhao; Hansen, Michael Jørgen;

    2012-01-01

    Observed hydrogen sulfide uptake rates in a biofilter treating waste air from a pig farm were too high to be explained within conventional limits of sulfide solubility, diffusion in a biofilm and bacterial metabolism. Clone libraries of 16S and 18S rRNA genes from the biofilter found no sulfide...

  10. Sulfide oxidation in a biofilter

    DEFF Research Database (Denmark)

    Pedersen, Claus Lunde; Dezhao, Liu; Hansen, Michael Jørgen;

    Observed hydrogen sulfide uptake rates in a biofilter treating waste air from a pig farm were too high to be explained within conventional limits of sulfide solubility, diffusion in a biofilm and bacterial metabolism. Clone libraries of 16S and 18S rRNA genes from the biofilter found no sulfide...

  11. Application of TSH bioindicator for studying the biological efficiency of neutrons from californium-252 source

    Energy Technology Data Exchange (ETDEWEB)

    Cebulska-Wasilewska, A.; Rekas, K. [Institute of Nuclear Physics, Cracow (Poland); Kim, J.K. [Korea Atomic Energy Research Inst., Taejon (Korea, Republic of)

    1997-12-31

    The effectiveness of neutrons from a Californium-252 source in the induction of various abnormalities in the Tradescantia clone 4430 stamen hair cells (TSH-assay) was studied. The special attention was paid to check whether any enhancement in effects caused by process of boron neutron capture is visible in the cells enriched with boron ions. Two chemicals (borax and BSH) were applied to introduce boron-10 ions into cells. Inflorescence, normal or pretreated with chemicals containing boron, were irradiated in the air with neutrons from a Cf-252 source at KAERI, Taejon, Korea. To estimate the relative biological effectiveness (RBE) in the induction of gene mutations of the neutron beam under the study, Tradescantia inflorescences, without any chemical pretreatment, were irradiated with various doses of X-rays. The ranges of radiation doses used were 0-0.1 Gy in neutrons and 0-0.5 Gy in X-rays. After the time needed to complete the postirradiation repair Tradescantia cuttings were transferred to Cracow, where screening of gene and lethal; mutations, cell cycle alterations in somatic cells have been done, and dose response relationships were figured. The maximal RBE values were estimated in the range of 4.6-6.8. Alterations of RBE value were observed; from 6.8 to 7.8 in the case of plants pretreated with 240 ppm of B-10 from borax, and 4.6 to 6.1 in the case of 400 ppm of B-10 from BSH. Results showed a slight, although statistically insignificant increase in biological efficacy of radiation from the Cf-252 source in samples pretreated with boron containing chemicals. (author)

  12. Application of TSH bioindicator for studying the biological efficiency of neutrons from californium-252 source

    International Nuclear Information System (INIS)

    The effectiveness of neutrons from a Californium-252 source in the induction of various abnormalities in the Tradescantia clone 4430 stamen hair cells (TSH-assay) was studied. The special attention was paid to check whether any enhancement in effects caused by process of boron neutron capture is visible in the cells enriched with boron ions. Two chemicals (borax and BSH) were applied to introduce boron-10 ions into cells. Inflorescence, normal or pretreated with chemicals containing boron, were irradiated in the air with neutrons from a Cf-252 source at KAERI, Taejon, Korea. To estimate the relative biological effectiveness (RBE) in the induction of gene mutations of the neutron beam under the study, Tradescantia inflorescences, without any chemical pretreatment, were irradiated with various doses of X-rays. The ranges of radiation doses used were 0-0.1 Gy in neutrons and 0-0.5 Gy in X-rays. After the time needed to complete the postirradiation repair Tradescantia cuttings were transferred to Cracow, where screening of gene and lethal; mutations, cell cycle alterations in somatic cells have been done, and dose response relationships were figured. The maximal RBE values were estimated in the range of 4.6-6.8. Alterations of RBE value were observed; from 6.8 to 7.8 in the case of plants pretreated with 240 ppm of B-10 from borax, and 4.6 to 6.1 in the case of 400 ppm of B-10 from BSH. Results showed a slight, although statistically insignificant increase in biological efficacy of radiation from the Cf-252 source in samples pretreated with boron containing chemicals. (author)

  13. Oxygen enhancement ratio (OER) and therapeutic gain factor (GF) for californium-252 at low dose rate

    International Nuclear Information System (INIS)

    The potential benefit of the introduction of californium-252 in interstitial and intracavitary therapy is related to the greater efficiency of its neutron emission against anoxic cancer cells. In that respect, the oxygen enhancement ratio (OER) of the 252Cf emission has been determined for a continuous low dose rate irradiation. The biological system is growth inhibition in Vicia faba bean roots. A new Vicia faba ''BelB'' strain has been used, which better tolerates long periods (up to about 10 hours) of anoxia. In a first series of experiments, for a 252Cf (Dsub(n+γ)) dose rate of 0.11 Gy.h-1, an OER of 1.4+-0.1 was observed (the γ contribution Dγ to the total absorbed dose Dsub(n+γ) was 0.35 at the position of the root tips). In a second series of experiments, in somewhat different geometrical conditions with a 252Cf (Dsub(n+γ)) dose rate of 0.13 Gy.h-1, an OER of 1.5+-0.1 was observed (Dγ/Dsub(n+γ)=0.42). The OER values observed for similar irradiation times, with iridium-192 γ-rays, were 2.3+-0.2 and 2.6+-0.1 respectively, which leads to therapeutic gain factors (GF) of 1.6 and 1.7 respectively. These GF values are slightly lower than those previously obtained (GF=1.8) on the same system, with d(50)-Be p(75)-Be and 15 MeV neutron beams

  14. Clinical Report on Californium-252 Neutron Intraluminal Brachytherapy Combined with External Irradiation for Cervical Carcinoma Treatment

    Institute of Scientific and Technical Information of China (English)

    Huanyu Zhao; Keming Wang; Jian Sun; Xin Geng; Weiming Zhang

    2006-01-01

    OBJECTIVE To observe the curative effects and complications of californium-252 (252Cf) neutron intraluminal brachytherapy (IBT) combined with external irradiation (El) for treatment of cervical carcinoma.METHODS From December 2000 to December 2004, 128 cases of cervical carcinoma staged into ⅡA~ⅢB according to the International Federation of Gynecology and Obstetrics (FIGO) standards were treated with 252Cf neutron IBT using 8~10 Gy per fraction, once a week. The total dose at reference A point was 36~40 Gy in 4~5 fractions. From the second day after 252Cf neutron IBT treatment, the whole pelvic cavity was treated with 60Co γ-ray El, applying 2 Gy per fraction, 4 times per week. After 20~25 Gy of El, the center of the whole pelvic field was blocked with 4 cm of lead in width. The total dose of El was 45~50 Gy.RESULTS The short-term therapeutic effects were CR 95.3% and PR 4.7%. The 3 and 5-year local control rates were 93.5% and 87.9%. The overall 3-year survival rate was 87.5% and for Stages Ⅱ and Ⅲ , 90.9%and 81.5% respectively; the overall 5-year survival rate was 70% and for Stages Ⅱ and Ⅲ, 76.2% and 61% respectively. The rate of radiation complications was 4.7% for radiation cystitis, 7.8% for radiation proctitis, 6.3%for vagina contracture and adhesion and 5.5% for protracted radiation proctitis.CONCLUSION An combination of 252Cf neutron IBT with El for treatment of cervical carcinoma can be well-tolerated by cervical carcinoma patients. The rate of local tumor control is high and radiation complications are few.

  15. Divalent and trivalent gas-phase coordination complexes of californium: evaluating the stability of Cf(ii).

    Science.gov (United States)

    Dau, Phuong D; Shuh, David K; Sturzbecher-Hoehne, Manuel; Abergel, Rebecca J; Gibson, John K

    2016-08-01

    The divalent oxidation state is increasingly stable relative to the trivalent state for the later actinide elements, with californium the first actinide to exhibit divalent chemistry under moderate conditions. Although there is evidence for divalent Cf in solution and solid compounds, there are no reports of discrete complexes in which Cf(II) is coordinated by anionic ligands. Described here is the divalent Cf methanesulfinate coordination complex, Cf(II)(CH3SO2)3(-), prepared in the gas phase by reductive elimination of CH3SO2 from Cf(III)(CH3SO2)4(-). Comparison with synthesis of the corresponding Sm and Cm complexes reveals reduction of Cf(III) and Sm(III), and no evidence for reduction of Cm(III). This reflects the comparative 3+/2+ reduction potentials: Cf(3+) (-1.60 V) ≈ Sm(3+) (-1.55 V) ≫ Cm(3+) (-3.7 V). Association of O2 to the divalent complexes is attributed to formation of superoxides, with recovery of the trivalent oxidation state. The new gas-phase chemistry of californium, now the heaviest element to have been studied in this manner, provides evidence for Cf(II) coordination complexes and similar chemistry of Cf and Sm. PMID:27424652

  16. Sulfide detoxification in plant mitochondria.

    Science.gov (United States)

    Birke, Hannah; Hildebrandt, Tatjana M; Wirtz, Markus; Hell, Rüdiger

    2015-01-01

    In contrast to animals, which release the signal molecule sulfide in small amounts from cysteine and its derivates, phototrophic eukaryotes generate sulfide as an essential intermediate of the sulfur assimilation pathway. Additionally, iron-sulfur cluster turnover and cyanide detoxification might contribute to the release of sulfide in mitochondria. However, sulfide is a potent inhibitor of cytochrome c oxidase in mitochondria. Thus, efficient sulfide detoxification mechanisms are required in mitochondria to ensure adequate energy production and consequently survival of the plant cell. Two enzymes have been recently described to catalyze sulfide detoxification in mitochondria of Arabidopsis thaliana, O-acetylserine(thiol)lyase C (OAS-TL C), and the sulfur dioxygenase (SDO) ethylmalonic encephalopathy protein 1 (ETHE1). Biochemical characterization of sulfide producing and consuming enzymes in mitochondria of plants is fundamental to understand the regulatory network that enables mitochondrial sulfide homeostasis under nonstressed and stressed conditions. In this chapter, we provide established protocols to determine the activity of the sulfide releasing enzyme β-cyanoalanine synthase as well as sulfide-consuming enzymes OAS-TL and SDO. Additionally, we describe a reliable and efficient method to purify OAS-TL proteins from plant material.

  17. Solving the Hydration Structure of the Heaviest Actinide Aqua Ion Known: The Californium(III) Case

    Energy Technology Data Exchange (ETDEWEB)

    Den Auwer, Ch.; Guillaumont, D. [CEA Marcoule, Nucl Energy Div, Radiochem Proc Dept, SCPS LILA, 30 (France); Galbis, E.; Pappalardo, Rafael R.; Marcos Sanchez, E. [Univ Seville, Dept Quim Fis, E-41012 Seville (Spain); Hernandez-Cobos, J. [Inst Ciencias Fis, Cuernavaca 62251, Morelos (Mexico); Le Naour, C.; Simoni, E. [Univ Paris Sud, Inst Phys Nucl Orsay, Paris (France)

    2010-07-01

    In summary, the first MC simulation of the trivalent cation of californium, based on an exchangeable hydrated ion-water intermolecular potential, has been shown to extend and improve the hydrated ion model. Likewise, the CfL{sub III}-edge EXAFS spectrum of an acidic 1 mm Cf(ClO{sub 4}){sub 3} aqueous solution recorded under optimized experimental conditions has greatly improved the signal/noise ratio of the only previously recorded spectrum. The comparison of the experimental EXAFS spectrum with the two computed ones, obtained from two different intermolecular potentials that predict eight (BP86) or nine (MP2) water molecules in the first coordination shell, leads to the conclusion that the lowest hydration number is preferred. Then, as Cf{sup III} is the heaviest actinide aqua ion for which there is experimental information, the actinide contraction is supported by the present study. (For U{sup III}, R{sub U-O}=2.56 Angstroms, and CN=9{+-}1; for Pu{sup III}, R{sub Pu-O}=2.51 Angstroms and CN=9{+-}1; for Cm{sup III}, R{sub Cm-O}=2.47 Angstroms and CN=9{+-}1). The role of the second hydration shell is important in defining the structure and dynamics of the Cf{sup III} aqua ion, but the contribution of second-shell water molecules to the EXAFS signal as back-scatters is marginal. Finally, this work gives an illustrative example of the benefits which can be achieved from the combination of experimental X-ray absorption spectroscopy and computer simulations. The usefulness of the simultaneous analysis of the results as well as the importance of the structural statistical average has been clearly demonstrated herein. Each technique independently was not adequate. We believe that this study traces out a still poorly explored combined methodology which may be extremely useful for many other complexes and chemical problems. A systematic theoretical and experimental examination of the other known actinide cations on the same basis should be undertaken to confirm the

  18. A novel method for improving cerussite sulfidization

    Institute of Scientific and Technical Information of China (English)

    Qi-cheng Feng; Shu-ming Wen; Wen-juan Zhao; Qin-bo Cao; Chao L

    2016-01-01

    Evaluation of flotation behavior, solution measurements, and surface analyses were performed to investigate the effects of chloride ion addition on the sulfidization of cerussite in this study. Micro-flotation tests indicate that the addition of chloride ions prior to sulfidization can significantly increase the flotation recovery of cerussite, which is attributed to the formation of more lead sulfide species on the mineral surface. Solution measurement results suggest that the addition of chloride ions prior to sulfidization induces the transformation of more sul-fide ions from pulp solution onto the mineral surface by the formation of more lead sulfide species. X-ray diffraction and energy-dispersive spectroscopy indicate that more lead sulfide species form on the mineral surface when chloride ions are added prior to sulfidization. These results demonstrate that the addition of chloride ions prior to sulfidization can significantly improve the sulfidization of cerussite, thereby enhancing the flotation performance.

  19. Sulfide intrusion and detoxification in Zostera marina

    DEFF Research Database (Denmark)

    Hasler-Sheetal, Harald; Holmer, Marianne

    2014-01-01

    Sulfide intrusion in seagrasses represents a global threat to seagrasses. In contrast seegrasses grow in hostile sediments, where they are constantly exposed to sulfide intrusion. Little is known about the strategies to survive sulfide intrusion, if there are detoxification mechanisms and sulfur...... nutrition in general. By a global review of sulfide intrusion, coupled with a series of field studies and in situ experiments we elucidate sulfide intrusion and different strategies of seagrasses to sustain sulfide intrusion. Using stable isotope tracing, scanning electron microscopy with x-ray analysis...... to trace sulfur compounds and as well as metabolomics upon sulfide and anoxia exposure we identified different strategies to cope with sulfidic sediments. 1) Avoidance, by reoxidation of gaseous sulfide in the arenchyma to elemental sulfur and sulfate; where precipitation of sulfide occurred as non...

  20. Prevention of sulfide oxidation in sulfide-rich waste rock

    Science.gov (United States)

    Nyström, Elsa; Alakangas, Lena

    2015-04-01

    The ability to reduce sulfide oxidation in waste rock after mine closure is a widely researched area, but to reduce and/or inhibit the oxidation during operation is less common. Sulfide-rich (ca 30 % sulfur) waste rock, partially oxidized, was leached during unsaturated laboratory condition. Trace elements such as As and Sb were relatively high in the waste rock while other sulfide-associated elements such as Cu, Pb and Zn were low compared to common sulfide-rich waste rock. Leaching of unsaturated waste rock lowered the pH, from around six down to two, resulting in continuously increasing element concentrations during the leaching period of 272 days. The concentrations of As (65 mg/L), Cu (6.9 mg/L), Sb (1.2 mg/L), Zn (149 mg/L) and S (43 g/L) were strongly elevated at the end of the leaching period. Different alkaline industrial residues such as slag, lime kiln dust and cement kiln dust were added as solid or as liquid to the waste rock in an attempt to inhibit sulfide oxidation through neo-formed phases on sulfide surfaces in order to decrease the mobility of metals and metalloids over longer time scale. This will result in a lower cost and efforts of measures after mine closure. Results from the experiments will be presented.

  1. Mechanochemical reduction of copper sulfide

    DEFF Research Database (Denmark)

    Balaz, P.; Takacs, L.; Jiang, Jianzhong;

    2002-01-01

    The mechanochemical reduction of copper sulfide with iron was induced in a Fritsch P-6 planetary mill, using WC vial filled with argon and WC balls. Samples milled for specific intervals were analyzed by XRD and Mossbauer spectroscopy. Most of the reaction takes place during the first 10 min...... of milling and only FeS and Cu are found after 60 min. The main chemical process is accompanied by phase transformations of the sulfide phases as a result of milling. Djurleite partially transformed to chalcocite and a tetragonal copper sulfide phase before reduction. The cubic modification of FeS was formed...... first, transforming to hexagonal during the later stages of the process. The formation of off-stoichiometric phases and the release of some elemental sulfur by copper sulfide are also probable....

  2. Pyrophoric nature of iron sulfides

    Energy Technology Data Exchange (ETDEWEB)

    Walker, R. [Univ. of Surrey, Guildford (United Kingdom). Dept. of Materials Science and Engineering; Steele, A.D.; Morgan, D.T.B. [Shell Research Centre Ltd., Chester (United Kingdom). Thornton Research Centre

    1996-05-01

    Hydrogen sulfide, often present in crude oil tankers, can react with rust to form various sulfides including mackinawite (FeS), greigite (Fe{sub 3}S{sub 4}), and pyrite (FeS{sub 2}). The tendency for these compounds to react with oxygen in air to form potentially explosive mixtures depends upon their morphology and the environmental conditions. The experimentally determined heat of oxidation of finely divided mackinawite was {minus}7.45 kJ/g. For samples with a larger particle size and smaller surface area the values measured were lower due to incomplete oxidation of the sulfide. All the sulfides produced, whether from magnetite or acicular, prismatic or spherical geothite, were approximately spherical in form. The heat of oxidation of greigite was found to be approximately {minus}2100 kJ/mol, and the heat of formation of greigite is approximately {minus}320 kJ/mol.

  3. Hydrogen Sulfide Oxidation by Myoglobin.

    Science.gov (United States)

    Bostelaar, Trever; Vitvitsky, Victor; Kumutima, Jacques; Lewis, Brianne E; Yadav, Pramod K; Brunold, Thomas C; Filipovic, Milos; Lehnert, Nicolai; Stemmler, Timothy L; Banerjee, Ruma

    2016-07-13

    Enzymes in the sulfur network generate the signaling molecule, hydrogen sulfide (H2S), from the amino acids cysteine and homocysteine. Since it is toxic at elevated concentrations, cells are equipped to clear H2S. A canonical sulfide oxidation pathway operates in mitochondria, converting H2S to thiosulfate and sulfate. We have recently discovered the ability of ferric hemoglobin to oxidize sulfide to thiosulfate and iron-bound hydropolysulfides. In this study, we report that myoglobin exhibits a similar capacity for sulfide oxidation. We have trapped and characterized iron-bound sulfur intermediates using cryo-mass spectrometry and X-ray absorption spectroscopy. Further support for the postulated intermediates in the chemically challenging conversion of H2S to thiosulfate and iron-bound catenated sulfur products is provided by EPR and resonance Raman spectroscopy in addition to density functional theory computational results. We speculate that the unusual sensitivity of skeletal muscle cytochrome c oxidase to sulfide poisoning in ethylmalonic encephalopathy, resulting from the deficiency in a mitochondrial sulfide oxidation enzyme, might be due to the concentration of H2S by myoglobin in this tissue. PMID:27310035

  4. Development of electron beam ion source charge breeder for rare isotopes at Californium Rare Isotope Breeder Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Kondrashev, S.; Dickerson, C.; Levand, A.; Ostroumov, P. N.; Pardo, R. C.; Savard, G.; Vondrasek, R. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Alessi, J.; Beebe, E.; Pikin, A. [Collider-Accelerator Department, Brookhaven National Laboratory, Upton, New York 11973 (United States); Kuznetsov, G. I.; Batazova, M. A. [Budker Institute of Nuclear Physics, Novosibirsk 630090 (Russian Federation)

    2012-02-15

    Recently, the Californium Rare Isotope Breeder Upgrade (CARIBU) to the Argonne Tandem Linac Accelerator System (ATLAS) was commissioned and became available for production of rare isotopes. Currently, an electron cyclotron resonance ion source is used as a charge breeder for CARIBU beams. To further increase the intensity and improve the purity of neutron-rich ion beams accelerated by ATLAS, we are developing a high-efficiency charge breeder for CARIBU based on an electron beam ion source (EBIS). The CARIBU EBIS charge breeder will utilize the state-of-the-art EBIS technology recently developed at Brookhaven National Laboratory (BNL). The electron beam current density in the CARIBU EBIS trap will be significantly higher than that in existing operational charge-state breeders based on the EBIS concept. The design of the CARIBU EBIS charge breeder is nearly complete. Long-lead components of the EBIS such as a 6-T superconducting solenoid and an electron gun have been ordered with the delivery schedule in the fall of 2011. Measurements of expected breeding efficiency using the BNL Test EBIS have been performed using a Cs{sup +} surface ionization ion source for external injection in pulsed mode. In these experiments we have achieved {approx}70% injection/extraction efficiency and breeding efficiency into the most abundant charge state of {approx}17%.

  5. Development of electron beam ion source charge breeder for rare isotopes at Californium Rare Isotope Breeder Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Kondrashev S.; Alessi J.; Dickerson, C.; Levand, A.; Ostroumov, P.N.; Pardo, R.C.; Savard, G.; Vondrasek, R.; Beebe, E.; Pikin, A.; Kuznetsov, G.I.; Batazova, M.A.

    2012-02-03

    Recently, the Californium Rare Isotope Breeder Upgrade (CARIBU) to the Argonne Tandem Linac Accelerator System (ATLAS) was commissioned and became available for production of rare isotopes. Currently, an electron cyclotron resonance ion source is used as a charge breeder for CARIBU beams. To further increase the intensity and improve the purity of neutron-rich ion beams accelerated by ATLAS, we are developing a high-efficiency charge breeder for CARIBU based on an electron beam ion source (EBIS). The CARIBU EBIS charge breeder will utilize the state-of-the-art EBIS technology recently developed at Brookhaven National Laboratory (BNL). The electron beam current density in the CARIBU EBIS trap will be significantly higher than that in existing operational charge-state breeders based on the EBIS concept. The design of the CARIBU EBIS charge breeder is nearly complete. Long-lead components of the EBIS such as a 6-T superconducting solenoid and an electron gun have been ordered with the delivery schedule in the fall of 2011. Measurements of expected breeding efficiency using the BNL Test EBIS have been performed using a Cs{sup +} surface ionization ion source for external injection in pulsed mode. In these experiments we have achieved {approx}70% injection/extraction efficiency and breeding efficiency into the most abundant charge state of {approx}17%.

  6. Long-term effects of an intracavitary treatment with californium-252 on normal tissue. [Swine, /sup 226/Ra

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, M.F.; Beamer, J.L.; Mahony, T.D.; Cross, F.T.; Lund, J.E.; Endres, G.W.R.

    1976-01-01

    About one hundred fifty swine were exposed to either radium-226 or californium-252 sources in the uterine cervix to determine an RBE for both acute and long-term effects. That value for early changes in the tissues at risk in the treatment of cervical cancer was between 6.2 and 6.8. The incidence of complications increased with time after exposure, especially among animals treated with /sup 252/Cf. Analysis of rectal injury showed that ulceration occurred frequently within a year postexposure at doses between 1600 and 2400 rad calculated at 2 cm lateral to the source midline. Fat necrosis and smooth muscle atrophy, resulting in a local rectal stricture, were delayed changes observed in some animals. The lower ureter was the site for a greater frequency of complications than the GI tract. Ureteral stricture often occurred at doses of 1200 rad from /sup 252/Cf and 7000 rad from /sup 226/Ra. Observation of delayed effects in the uterine-cervix in animals held up to 4 years postexposure indicate that the RBE for /sup 252/Cf may be increased to a value as high as 18, while repair may have even decreased it to about 5.6 in the rectum. Fifty swine are still being observed for long-term effects after doses above 800 rad from /sup 252/Cf and 5000 rad from /sup 226/Ra.

  7. Synthesis of furan from allenic sulfide derivatives

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    In this paper, we report the synthesis of furan derivatives from allenic sulfides. By the reaction with NaH, β-Hydroxyl allenic sulfides were found to generate furan products in excellent yields with the removal of phenylthio group. β-Aldehyde allenic sulfides were found to give similar furan products with one more substituent when treated with additional nucleophilic reagents. β-ketone allenic sulfides can also cyclize to give furan derivatives with the promotion of P2O5.

  8. Synthesis of furan from allenic sulfide derivatives

    Institute of Scientific and Technical Information of China (English)

    PENG LingLing; ZHANG Xiu; MA Jie; ZHONG ZhenZhen; ZHANG Zhe; ZHANG Yan; WANG JianBo

    2009-01-01

    In this paper, we report the synthesis of furan derivatives from allenic sulfides. By the reaction with NaH.,β-Hydroxyl allenic sulfides were found to generate furan products in excellent yields with the removal of phenylthio group.β-Aldehyde allenic sulfides were found to give similar furan products with one more substituent when treated with additional nucleophilic reagents. β-ketone allenic sulfides can also cyclize to give furan derivatives with the promotion of P2O5.

  9. 30 CFR 250.604 - Hydrogen sulfide.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Hydrogen sulfide. 250.604 Section 250.604... OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Well-Workover Operations § 250.604 Hydrogen sulfide. When a well-workover operation is conducted in zones known to contain hydrogen sulfide (H2S) or...

  10. 30 CFR 250.808 - Hydrogen sulfide.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Hydrogen sulfide. 250.808 Section 250.808... OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Production Safety Systems § 250.808 Hydrogen sulfide. Production operations in zones known to contain hydrogen sulfide (H2S) or in zones where the presence of...

  11. 30 CFR 250.490 - Hydrogen sulfide.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Hydrogen sulfide. 250.490 Section 250.490... OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Hydrogen Sulfide § 250.490 Hydrogen... black lettering as follows: Letter height Wording 12 inches Danger. Poisonous Gas. Hydrogen Sulfide....

  12. 30 CFR 250.504 - Hydrogen sulfide.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Hydrogen sulfide. 250.504 Section 250.504... OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Well-Completion Operations § 250.504 Hydrogen sulfide. When a well-completion operation is conducted in zones known to contain hydrogen sulfide (H2S) or...

  13. Influence of arsenic on iron sulfide transformations

    NARCIS (Netherlands)

    Wolthers, M.; Butler, I.B.; Rickard, D.

    2007-01-01

    The association of arsenate, As(V), and arsenite, As(III), with disordered mackinawite, FeS, was studied in sulfide-limited (Fe:S = 1:1) and excess-sulfide (Fe:S = 1:2) batch experiments. In the absence of arsenic, the sulfide-limited experiments produce disordered mackinawite while the excess-sulfi

  14. STUDY OF HYDROGEN SULFIDE REMOVAL FROM GROUNDWATER

    Directory of Open Access Journals (Sweden)

    T. Lupascu

    2013-06-01

    Full Text Available The process of the hydrogen sulfide removal from the underground water of the Hancesti town has been investigated. By oxygen bubbling through the water containing hydrogen sulfide, from the Hancesti well tube, sulfur is deposited in the porous structure of studied catalysts, which decreases their catalytic activity. Concomitantly, the process of adsorption / oxidation of hydrogen sulfide to sulfate take place. The kinetic research of the hydrogen sulfide removal from the Hancesti underground water, after its treatment by hydrogen peroxide, proves greater efficiency than in the case of modified carbonic adsorbents. As a result of used treatment, hydrogen sulfide is completely oxidized to sulfates

  15. Ab initio full-potential study of mechanical properties and magnetic phase stability of californium monopnictides (CfN and CfP)

    Science.gov (United States)

    Amari, S.; Bouhafs, B.

    2016-09-01

    Based on the first-principles methods, the structural, elastic, electronic, properties and magnetic ordering of californium monopnictides CfX (X = P) have been studied using the full-potential augmented plane wave plus local orbitals (FP-L/APW + lo) method within the framework of density functional theory (DFT). The electronic exchange correlation energy is described by generalized gradient approximation GGA and GGA+U (U is the Hubbard correction). The GGA+U method is applied to the rare-earth 5f states. We have calculated the lattice parameters, bulk modulii and the first pressure derivatives of the bulk modulii. The elastic properties of the studied compounds are only investigated in the most stable calculated phase. In order to gain further information, we have calculated Young's modulus, shear modulus, anisotropy factor and Kleinman parameter by the aid of the calculated elastic constants. The results mainly show that californium monopnictides CfX (X = P) have an antiferromagnetic spin ordering. Density of states (DOS) and charge densities for both compounds are also computed in the NaCl (B1) structure.

  16. Sulfide intrusion and detoxification in seagrasses ecosystems

    DEFF Research Database (Denmark)

    Hasler-Sheetal, Harald; Holmer, Marianne

    Sulfide intrusion in seagrasses represents a global threat to seagrasses and thereby an important parameter in resilience of seagrass ecosystems. In contrast seegrasses colonize and grow in hostile sediments, where they are constantly exposed to invasion of toxic gaseous sulfide. Remarkably little...... is known about the strategies of seagrasses to survive sulfide intrusion, their potential detoxification mechanisms and sulfur nutrition in general. By a global review of sulfide intrusion, coupled with a series of field studies and in situ experiments we elucidate sulfide intrusion and different...... strategies of seagrasses to sustain sulfide intrusion. Using stable isotope tracing, scanning electron microscopy with x-ray analysis, tracing sulfur compounds combined with ecosystem parameters we found different spatial, intraspecific and interspecific strategies to cope with sulfidic sediments. 1...

  17. Redox Biochemistry of Hydrogen Sulfide*

    OpenAIRE

    Kabil, Omer; Banerjee, Ruma

    2010-01-01

    H2S, the most recently discovered gasotransmitter, might in fact be the evolutionary matriarch of this family, being both ancient and highly reduced. Disruption of γ-cystathionase in mice leads to cardiovascular dysfunction and marked hypertension, suggesting a key role for this enzyme in H2S production in the vasculature. However, patients with inherited deficiency in γ-cystathionase apparently do not present vascular pathology. A mitochondrial pathway disposes sulfide and couples it to oxid...

  18. Anatomy of a controversy: Application of the Langevin technique to the analysis of the Californium-252 Source-Driven Noise Analysis method for subcriticality determination

    International Nuclear Information System (INIS)

    The expressions for the power spectral density of the noise equivalent sources have been calculated explicitly for the (a) stochastic transport equation, (b) the one-speed transport equaton, (c) the one-speed P1 equations, (d) the one-speed diffusion equation and (e) the point kinetic equation. The stochastic nature of Fick's law in (d) has been emphasized. The Langevin technique has been applied at various levels of approximation to the interpretation of the Californium-252 Source-Driven Noise Analysis (CSDNA) experiment for determining the reactivity in subcritical media. The origin of the controversy surrounding this method has been explained. The foundations of the CSDNA method as a viable experimental technique to infer subcriticality from a measured ratio of power spectral densities of the outputs of two neutron detectors and a third external source detector has been examined by solving the one-speed stochastic diffusion equation for a point external Californium-252 source and two detectors in an infinite medium. The expression relating reactivity to the measured ratio of PSDs was found to depend implicitly on k itself. Through a numerical analysis fo this expression, the authors have demonstrated that for a colinear detector-source-detector configuration for neutron detectors far from the source, the expression for the subcritical multiplication factor becomes essentially insensitive to k, hence, demonstrating some possibility for the viability of this technique. However, under more realistic experimental conditions, i.e., for finite systems in which diffusion theroy is not applicable, the measurement of the subcritical multiplication factor from a single measured ratio of PSDs, without extensive transport calculations, remains doubtful

  19. Kinetic Studies of Sulfide Mineral Oxidation and Xanthate Adsorption

    OpenAIRE

    Mendiratta, Neeraj K.

    2000-01-01

    Sulfide minerals are a major source of metals; however, certain sulfide minerals, such as pyrite and pyrrhotite, are less desirable. Froth flotation is a commonly used separation technique, which requires the use of several reagents to float and depress different sulfide minerals. Xanthate, a thiol collector, has gained immense usage in sulfide minerals flotation. However, some sulfides are naturally hydrophobic and may float without a collector. Iron sulfides, such as pyrite and pyrrho...

  20. Hydrogen sulfide and vascular relaxation

    Institute of Scientific and Technical Information of China (English)

    SUN Yan; TANG Chao-shu; DU Jun-bao; JIN Hong-fang

    2011-01-01

    Objective To review the vasorelaxant effects of hydrogen sulfide (H2S) in arterial rings in the cardiovascular system under both physiological and pathophysiological conditions and the possible mechanisms involved.Data sources The data in this review were obtained from Medline and Pubmed sources from 1997 to 2011 using the search terms "hydrogen sulfide" and ""vascular relaxation".Study selection Articles describing the role of hydrogen sulfide in the regulation of vascular activity and its vasorelaxant effects were selected.Results H2S plays an important role in the regulation of cardiovascular tone.The vasomodulatory effects of H2S depend on factors including concentration,species and tissue type.The H2S donor,sodium hydrosulfide (NarS),causes vasorelaxation of rat isolated aortic rings in a dose-dependent manner.This effect was more pronounced than that observed in pulmonary arterial rings.The expression of KATP channel proteins and mRNA in the aortic rings was increased compared with pulmonary artery rings.H2S is involved in the pathogenesis of a variety of cardiovascular diseases.Downregulation of the endogenous H2S pathway is an important factor in the pathogenesis of cardiovascular diseases.The vasorelaxant effects of H2S have been shown to be mediated by activation of KATP channels in vascular smooth muscle cells and via the induction of acidification due to activation of the CI/HCO3 exchanger.It is speculated that the mechanisms underlying the vasoconstrictive function of H2S in the aortic rings involves decreased NO production and inhibition of cAMP accumulation.Conclusion H2S is an important endogenous gasotransmitter in the cardiovascular system and acts as a modulator of vascular tone in the homeostatic regulation of blood pressure.

  1. Variation in sulfide tolerance of photosystem II in phylogenetically diverse cyanobacteria from sulfidic habitats

    Science.gov (United States)

    Miller, Scott R.; Bebout, Brad M.

    2004-01-01

    Physiological and molecular phylogenetic approaches were used to investigate variation among 12 cyanobacterial strains in their tolerance of sulfide, an inhibitor of oxygenic photosynthesis. Cyanobacteria from sulfidic habitats were found to be phylogenetically diverse and exhibited an approximately 50-fold variation in photosystem II performance in the presence of sulfide. Whereas the degree of tolerance was positively correlated with sulfide levels in the environment, a strain's phenotype could not be predicted from the tolerance of its closest relatives. These observations suggest that sulfide tolerance is a dynamic trait primarily shaped by environmental variation. Despite differences in absolute tolerance, similarities among strains in the effects of sulfide on chlorophyll fluorescence induction indicated a common mode of toxicity. Based on similarities with treatments known to disrupt the oxygen-evolving complex, it was concluded that sulfide toxicity resulted from inhibition of the donor side of photosystem II.

  2. New biologically active hydrogen sulfide donors.

    Science.gov (United States)

    Roger, Thomas; Raynaud, Francoise; Bouillaud, Frédéric; Ransy, Céline; Simonet, Serge; Crespo, Christine; Bourguignon, Marie-Pierre; Villeneuve, Nicole; Vilaine, Jean-Paul; Artaud, Isabelle; Galardon, Erwan

    2013-11-25

    Generous donors: The dithioperoxyanhydrides (CH3 COS)2 , (PhCOS)2 , CH3 COSSCO2 Me and PhCOSSCO2 Me act as thiol-activated hydrogen sulfide donors in aqueous buffer solution. The most efficient donor (CH3 COS)2 can induce a biological response in cells, and advantageously replace hydrogen sulfide in ex vivo vascular studies. PMID:24115650

  3. Sulfide stress cracking of pipeline steels

    International Nuclear Information System (INIS)

    The problem of the sulfide stress corrosion cracking of pipeline steels and their welded joints have been presented for pipeline steels. Results of hydrogen sulfide stress cracking inhibitors and corrosion inhibitors of three types protective actions on pipeline steels of two grades petroleum range of products are given. (author)

  4. Ammonia and hydrogen sulfide removal using biochar

    Science.gov (United States)

    Reducing ammonia and hydrogen sulfide emissions from livestock facilities is an important issue for many communities and livestock producers. Ammonia has been regarded as odorous, precursor for particulate matter (PM), and contributed to livestock mortality. Hydrogen sulfide is highly toxic at elev...

  5. Sulfide toxicity kinetics of a uasb reactor

    Directory of Open Access Journals (Sweden)

    D. R. Paula Jr.

    2009-12-01

    Full Text Available The effect of sulfide toxicity on kinetic parameters of anaerobic organic matter removal in a UASB (up-flow anaerobic sludge blanket reactor is presented. Two lab-scale UASB reactors (10.5 L were operated continuously during 12 months. The reactors were fed with synthetic wastes prepared daily using glucose, ammonium acetate, methanol and nutrient solution. One of the reactors also received increasing concentrations of sodium sulfide. For both reactors, the flow rate of 16 L.d-1 was held constant throughout the experiment, corresponding to a hydraulic retention time of 15.6 hours. The classic model for non-competitive sulfide inhibition was applied to the experimental data for determining the overall kinetic parameter of specific substrate utilization (q and the sulfide inhibition coefficient (Ki. The application of the kinetic parameters determined allows prediction of methanogenesis inhibition and thus the adoption of operating parameters to minimize sulfide toxicity in UASB reactors.

  6. Californium-252 neutron sources

    International Nuclear Information System (INIS)

    Major production programs for the Savannah River reactors and the High Flux Isotopes Reactor at Oak Ridge have made 252Cf one of the most available and, at the USAEC's sales price of $10/μg, one of the least-expensive isotopic neutron sources. Reactor production has totaled approximately 2 g, and, based on expected demand, an additional 10 g will be produced in the next decade. The approximately 800 mg chemically separated to date has been used to prepare over 600 neutron sources. Most, about 500, have been medical sources containing 1 to 5 μg of 252Cf plated in needles for experimental cancer therapy studies. The remainder have generally been point sources containing 10 μg to 12 mg of oxide for activation, well logging, or radiography uses. Bulk sources have also been supplied to the commercial encapsulators. The latest development has been the production of 252Cf cermet wire which can be cut into almost contamination-free lengths of the desired 252Cf content. Casks are available for transport of sources up to 50 mg. Subcritical assemblies have been developed to multiply the source neutrons by a factor of 10 to 40, and collimators and thermalizers have also been extensively developed to shape the neutron flux and energy distributions for special applications. (U.S.)

  7. Primordial Xenon in Allende Sulfides

    Science.gov (United States)

    Lee, J. T.; Manuel, O. K.

    1995-09-01

    The Allende C3V carbonaceous chondrite incorporated isotopically anomalous components of several medium-heavy elements (Z=36-62) from nucleosynthesis [1]. Isotopically distinct Xe (Z=54) has been found in grains ranging from several _ to a few mm in size. Diamond [2] is the host of Xe that is enriched in isotopes produced by the very rapid p- and r-processes in a supernova explosion [3]. Silicon carbide [4] is the host of Xe that is enriched in the middle isotopes, 128-132Xe, produced by slow neutron capture [3] before a star reaches the supernova stage. The present study was undertaken to identify the isotopic composition of primitive Xe initially trapped in sulfides of the Allende meteorite. Two FeS mineral separates were analyzed by stepwise heating. One sample was first irradiated in a neutron flux to generate a tracer isotope, 131*Xe, by the 130Te(n, gamma beta-)131*Xe reaction. The release pattern of this tracer isotope, 131*Xe, closely paralleled the release of primordial 132Xe up to 950 degrees C, when the sulfide melted and released the bulk of its trapped Xe (Figure 1). The Xe released from both samples at 950 deg C was terrestrial in isotopic composition, except for enrichments from spallogenic and radiogenic components (Figure 2). From the results of this and earlier analyses of Xe in meteoritic FeS [5, 6, 7], we conclude that terrestrial-type Xe was dominant in the central region of the protoplanetary nebula, and it remains a major component in the FeS of diverse meteorites and in the terrestrial planets that are rich in Fe, S [8]. References: [1] Begemann F. (1993) Origin and Evolution of the Elements (N. Prantzos et al., eds.), 518-527, Cambridge Univ. [2] Lewis R. S. and Anders E. (1988) LPS XIX, 679-680. [3] Burbidge et al. (1957) Rev. Modern Phys., 29, 547-650. [4] Tang M. and Anders E. (1988) GCA, 52, 1235-1244. [5] Niemeyer S. (1979) GCA, 43, 843-860. [6] Lewis et al. (1979) GCA, 43, 1743-1752. [7] Hwaung G. and Manuel O. K. (1982) Nature, 299

  8. Pelletizing of sulfide molybdenite concentrates

    Science.gov (United States)

    Palant, A. A.

    2007-04-01

    The results of a pelletizing investigation using various binding components (water, syrup, sulfite-alcohol distillery grains, and bentonite) of the flotation sulfide molybdenite concentrate (˜84% MoS2) from the Mongolian deposit are discussed. The use of syrup provides rather high-strength pellets (>3 N/pellet or >300 g/pellet) of the required size (2 3 mm) for the consumption of 1 kg binder per 100 kg concentrate. The main advantage of the use of syrup instead of bentonite is that the molybdenum cinder produced by oxidizing roasting of raw ore materials is not impoverished due to complete burning out of the syrup. This fact exerts a positive effect on the subsequent hydrometallurgical process, decreasing molybdenum losses related to dump cakes.

  9. Adequate hydrogen sulfide, healthy circulation

    Institute of Scientific and Technical Information of China (English)

    DU Jun-bao; CHEN Stella; JIN Hong-fang; TANG Chao-shu

    2011-01-01

    Previously,hydrogen sulfide (H2S) was considered to be a toxic gas.However,recently it was discovered that it could be produced in mammals and even in plants,throughtheproductionandmetabolismof sulfur-containing amino acids.In mammals,H2S is mainly catalyzed by cystathionine-γ-lyase (CSE),cystathionin-β-lyase (CBS) and 3-mercaptopyruvate sulfurtransferase (MPST) with the substrate of L-cysteine.Endogenous H2S exerts many important physiological and pathophysiological functions,including hypotensive action,vasorelaxation,myocardial dilation,inhibition of smooth muscle cell proliferation,and antioxidatve actions.Importantly,it plays a very important role in the pathogenesis of systemic hypertension,pulmonary hypertension,atherosclerosis,myocardialinjury,angiogenesis,hyperhomocysteinemi aandshock.Therefore,H2S is now being considered to be a novel gasotransmitter after nitric oxide and carbon monoxide in the regulation of circulatory system.

  10. Structural studies in limestone sulfidation

    Energy Technology Data Exchange (ETDEWEB)

    Fenouil, L.A.; Lynn, S.

    1993-05-01

    This study investigates the sulfidation of limestone at high temperatures (700--900{degree}C) as the first step in the design of a High-Temperature Coal-Gas Clean-Up system using millimeter-size limestone particles. Several workers have found that the rate of this reaction significantly decreases after an initial 10 to 15% conversion of CaCO{sub 3} to CaS. The present work attempts to explain this feature. It is first established that millimeter-size limestone particles do not sinter at temperatures up to the CaCO{sub 3} calcination point (899{degree}C at 1.03 bar CO{sub 2} partial pressure). It is then shown that CaS sinters rapidly at 750 to 900{degree}C if CO{sub 2} is present in the gas phase. Scanning Electron Microscope (SEM) photographs and Electron Dispersive Spectroscopy (EDS) data reveal that the CaS product layer sinters and forms a quasi-impermeable coating around the CaCO{sub 3} grains that greatly hinders more H{sub 2}S from reaching the still unreacted parts of the stone. Moreover, most of the pores initially present within the limestone structure begin to disappear or, at least, are significantly reduced in size. From then on, subsequent conversion is limited by diffusion of H{sub 2}S through the CaS layer, possibly by S{sup 2{minus}} ionic diffusion. The kinetics is then adequately described by a shrinking-core model, in which a sharp front of completely converted limestone is assumed to progress toward the center of the pellet. Finally, experimental evidence and computer simulations using simple sintering models suggest that the CaS sintering, responsible for the sharp decrease in the sulfidation rate, is surface-diffusion controlled.

  11. Microbial control of hydrogen sulfide production

    Energy Technology Data Exchange (ETDEWEB)

    Montgomery, A.D.; Bhupathiraju, V.K.; Wofford, N.; McInerney, M.J. [Univ. of Oklahoma, Tulsa, OK (United States)] [and others

    1995-12-31

    A sulfide-resistant strain of Thiobacillus denitrificans, strain F, prevented the accumulation of sulfide by Desulfovibrio desulfuricans when both organisms were grown in liquid medium. The wild-type strain of T. denitrificans did not prevent the accumulation of sulfide produced by D. desulfuricans. Strain F also prevented the accumulation of sulfide by a mixed population of sulfate-reducing bacteria enriched from an oil field brine. Fermentation balances showed that strain F stoichiometrically oxidized the sulfide produced by D. desulfuricans and the oil field brine enrichment to sulfate. The ability of a strain F to control sulfide production in an experimental system of cores and formation water from the Redfield, Iowa, natural gas storage facility was also investigated. A stable, sulfide-producing biofilm was established in two separate core systems, one of which was inoculated with strain F while the other core system (control) was treated in an identical manner, but was not inoculated with strain F. When formation water with 10 mM acetate and 5 mM nitrate was injected into both core systems, the effluent sulfide concentrations in the control core system ranged from 200 to 460 {mu}M. In the test core system inoculated with strain F, the effluent sulfide concentrations were lower, ranging from 70 to 110 {mu}M. In order to determine whether strain F could control sulfide production under optimal conditions for sulfate-reducing bacteria, the electron donor was changed to lactate and inorganic nutrients (nitrogen and phosphate sources) were added to the formation water. When nutrient-supplemented formation water with 3.1 mM lactate and 10 mM nitrate was used, the effluent sulfide concentrations of the control core system initially increased to about 3,800 {mu}M, and then decreased to about 1,100 {mu}M after 5 weeks. However, in the test core system inoculated with strain F, the effluent sulfide concentrations were much lower, 160 to 330 {mu}M.

  12. Iron-sulfide crystals in probe deposits

    DEFF Research Database (Denmark)

    Laursen, Karin; Frandsen, Flemming

    1998-01-01

    Iron-sulfides were observed in deposits collected on a probe inserted at the top of the furnace of a coal-fired power station in Denmark. The chemical composition of the iron-sulfides is equivalent to pyrrhotite (FeS). The pyrrhotites are present as crystals and, based on the shape of the crystals......: (1) impact of low viscous droplets of iron sulfide; and (2) sulfur diffusion. Previous research on the influence of pyrite on slagging focused on the decomposition of pyrite into pyrrhotite and especially on the oxidation stage of this product during impact on the heat transfer surfaces...

  13. Phase Engineering of 2D Tin Sulfides.

    OpenAIRE

    Mutlu, Z; Wu, RJ; Wickramaratne, D.; Shahrezaei, S; Liu, C; Temiz, S; Patalano, A; M Ozkan; Lake, RK; Mkhoyan, KA; Ozkan, CS

    2016-01-01

    Tin sulfides can exist in a variety of phases and polytypes due to the different oxidation states of Sn. A subset of these phases and polytypes take the form of layered 2D structures that give rise to a wide host of electronic and optical properties. Hence, achieving control over the phase, polytype, and thickness of tin sulfides is necessary to utilize this wide range of properties exhibited by the compound. This study reports on phase-selective growth of both hexagonal tin (IV) sulfide SnS2...

  14. Sulfide Intrusion and Detoxification in the Seagrass Zostera marina

    DEFF Research Database (Denmark)

    Hasler-Sheetal, Harald; Holmer, Marianne

    2015-01-01

    Gaseous sulfide intrusion into seagrasses growing in sulfidic sediments causes little or no harm to the plant, indicating the presence of an unknown sulfide tolerance or detoxification mechanism. We assessed such mechanism in the seagrass Zostera marina in the laboratory and in the field...... as sulfate throughout the plant. We conclude that avoidance of sulfide exposure by reoxidation of sulfide in the rhizosphere or aerenchyma and tolerance of sulfide intrusion by incorporation of sulfur in the plant are likely major survival strategies of seagrasses in sulfidic sediments....

  15. Formation of Copper Sulfide Artifacts During Electrolytic Dissolution of Steel

    Science.gov (United States)

    Tan, Jia; Pistorius, P. Chris

    2013-06-01

    Based on equilibrium considerations, copper sulfide is not expected to form in manganese-containing steel, yet previous workers reported finding copper sulfide in transmission electron microscope samples which had been prepared by electropolishing. It is proposed that copper sulfide can form during electrolytic dissolution because of the much greater stability of copper sulfide relative to manganese sulfide in contact with an electrolyte containing copper and manganese cations. This mechanism has been demonstrated with aluminum-killed steel samples.

  16. High temperature sulfide corrosion and transport properties of transition metal sulfides

    International Nuclear Information System (INIS)

    An overview is presented of the role of the defect and transport properties of transition metal sulfides on the kinetics and mechanism of high-temperature sulfide corrosion of metals and alloys. It has been shown that due to the very high concentration of defects in common metal sulfides, not only pure metals but also conventional high-temperature alloys (chromia and alumina formers) undergo very rapid degradation in highly sulfidizing environments. Refractory metals (Mo, Nb), on the other hands, are highly resistant to sulfide corrosion, their sulfidation rates being comparable with the oxidation rate of chromium. Also, alloying of common metals by niobium and molybdenum improve considerably corrosion resistance with respect to highly sulfidizing atmospheres. It has demonstrated that Al.-Mo and Al.-Mo-Si alloys shown excellent resistant to sulfidizing environments, these materials being also simultaneously oxidation resistant. Thus, new prospects have been created for the development of a new generation of coating materials, resistant to multicomponent sulfidizing-oxidizing atmospheres, often encountered in many branches of modern technology. (author)

  17. Inorganic sorbents for concentration of hydrogen sulfide

    International Nuclear Information System (INIS)

    Present work is devoted to application of inorganic sorbents for concentration of hydrogen sulfide. The elaboration of method is conducted under controlled concentrations of hydrogen sulphide from 1.00 til 0.01 mg/l.

  18. Managing hydrogen sulfide the natural way

    Energy Technology Data Exchange (ETDEWEB)

    Beasley, T.; Abry, R.G.F. [New Paradigm Gas Processing Ltd., Calgary, AB (Canada)

    2003-07-01

    This paper explores the benefits and costs associated with acid gas injection versus flaring and venting. It provides an update of Shell Paques biological gas desulfurization technology and the world's first high pressure application of the technology at the EnCana Bantry Project. The process is particularly well suited to treat sour (acid) natural gases that are currently being flared. It can also be used as an alternative to acid gas injection. Complete removal of hydrogen sulfide can be achieved by selective biotechnological conversion of hydrogen sulfide to elemental sulfur. Compared to conventional processes, this breakthrough technology achieves greater savings in terms of capital and operational costs. The Shell-Paque process produces up to 50 tonnes of sulfur per day with virtually complete conversion of hydrogen sulfide to elemental sulfur, resulting in no hydrogen sulfide based airborne emissions. 2 refs., 2 tabs., 35 figs.

  19. The Search for Interstellar Sulfide Grains

    Science.gov (United States)

    Keller, Lindsay P.; Messenger, Scott

    2010-01-01

    The lifecycle of sulfur in the galaxy is poorly understood. Fe-sulfide grains are abundant in early solar system materials (e.g. meteorites and comets) and S is highly depleted from the gas phase in cold, dense molecular cloud environments. In stark contrast, sulfur is essentially undepleted from the gas phase in the diffuse interstellar medium, indicating that little sulfur is incorporated into solid grains in this environment. It is widely believed that sulfur is not a component of interstellar dust grains. This is a rather puzzling observation unless Fe-sulfides are not produced in significant quantities in stellar outflows, or their lifetime in the ISM is very short due to rapid destruction. Fe sulfide grains are ubiquitous in cometary samples where they are the dominant host of sulfur. The Fe-sulfides (primarily pyrrhotite; Fe(1-x)S) are common, both as discrete 0.5-10 micron-sized grains and as fine (5-10 nm) nanophase inclusions within amorphous silicate grains. Cometary dust particles contain high abundances of well-preserved presolar silicates and organic matter and we have suggested that they should contain presolar sulfides as well. This hypothesis is supported by the observation of abundant Fe-sulfides grains in dust around pre- and post-main sequence stars inferred from astronomical spectra showing a broad 23 micron IR feature due to FeS. Fe-sulfide grains also occur as inclusions in bona fide circumstellar amorphous silicate grains and as inclusions within deuterium-rich organic matter in cometary dust samples. Our irradiation experiments show that FeS is far more resistant to radiation damage than silicates. Consequently, we expect that Fe sulfide stardust should be as abundant as silicate stardust in solar system materials.

  20. Mechanism of mechanical activation for sulfide ores

    Institute of Scientific and Technical Information of China (English)

    HU Hui-ping; CHEN Qi-yuan; YIN Zhou-lan; HE Yue-hui; HUANG Bai-yun

    2007-01-01

    Structural changes for mechanically activated pyrite, sphalerite, galena and molybdenite with or without the exposure to ambient air, were systematically investigated using X-ray diffraction analysis(XRD), particle size analysis, gravimetrical method, X-ray photo-electron spectroscopy(XPS) and scanning electron microscopy(SEM), respectively. Based on the above structural changes for mechanically activated sulfide ores and related reports by other researchers, several qualitative rules of the mechanisms and the effects of mechanical activation for sulfide ores are obtained. For brittle sulfide ores with thermal instability, and incomplete cleavage plane or extremely incomplete cleavage plane, the mechanism of mechanical activation is that a great amount of surface reactive sites are formed during their mechanical activation. The effects of mechanical activation are apparent. For brittle sulfide ores with thermal instability, and complete cleavage plane, the mechanism of mechanical activation is that a great amount of surface reactive sites are formed, and lattice deformation happens during their mechanical activation. The effects of mechanical activation are apparent. For brittle sulfide ores with excellent thermal stability, and complete cleavage plane, the mechanism of mechanical activation is that lattice deformation happens during their mechanical activation. The effects of mechanical activation are apparent. For sulfide ores with high toughness, good thermal stability and very excellent complete cleavage plane, the mechanism of mechanical activation is that lattice deformation happens during their mechanical activation, but the lattice deformation ratio is very small. The effects of mechanical activation are worst.

  1. Air-water transfer of hydrogen sulfide

    DEFF Research Database (Denmark)

    Yongsiri, C.; Vollertsen, J.; Rasmussen, M. R.;

    2004-01-01

    The emissions process of hydrogen sulfide was studied to quantify air–water transfer of hydrogen sulfide in sewer networks. Hydrogen sulfide transfer across the air–water interface was investigated at different turbulence levels (expressed in terms of the Froude number) and pH using batch...... experiments. By means of the overall mass–transfer coefficient (KLa), the transfer coefficient of hydrogen sulfide (KLaH2S), referring to total sulfide, was correlated to that of oxygen (KLaO2) (i.e., the reaeration coefficient). Results demonstrate that both turbulence and pH in the water phase play...... a significant role for KLaH2S. An exponential expression is a suitable representation for the relationship between KLaH2S and the Froude number at all pH values studied (4.5 to 8.0). Because of the dissociation of hydrogen sulfide, KLaH2S increased with decreasing pH at a constant turbulence level. Relative...

  2. Hydrogen sulfide can inhibit and enhance oxygenic photosynthesis in a cyanobacterium from sulfidic springs

    NARCIS (Netherlands)

    Klatt, Judith M.; Haas, Sebastian; Yilmaz, Pelin; de Beer, Dirk; Polerecky, Lubos

    2015-01-01

    We used microsensors to investigate the combinatory effect of hydrogen sulfide (H2S) and light on oxygenic photosynthesis in biofilms formed by a cyanobacterium from sulfidic springs. We found that photosynthesis was both positively and negatively affected by H2S: (i) H2S accelerated the recovery of

  3. Sulfide response analysis for sulfide control using a pS electrode in sulfate reducing bioreactors

    NARCIS (Netherlands)

    Villa Gomez, D.K.; Cassidy, J.; Keesman, K.J.; Sampaio, R.M.; Lens, P.N.L.

    2014-01-01

    Step changes in the organic loading rate (OLR) through variations in the influent chemical oxygen demand (CODin) concentration or in the hydraulic retention time (HRT) at constant COD/SO4 2- ratio (0.67) were applied to create sulfide responses for the design of a sulfide control in sulfate reducing

  4. Californium interrogation prompt neutron (CIPN) instrument for non-destructive assay of spent nuclear fuel-Design concept and experimental demonstration

    Science.gov (United States)

    Henzlova, D.; Menlove, H. O.; Rael, C. D.; Trellue, H. R.; Tobin, S. J.; Park, Se-Hwan; Oh, Jong-Myeong; Lee, Seung-Kyu; Ahn, Seong-Kyu; Kwon, In-Chan; Kim, Ho-Dong

    2016-01-01

    This paper presents results of the first experimental demonstration of the Californium Interrogation Prompt Neutron (CIPN) instrument developed within a multi-year effort launched by the Next Generation Safeguards Initiative Spent Fuel Project of the United States Department of Energy. The goals of this project focused on developing viable non-destructive assay techniques with capabilities to improve an independent verification of spent fuel assembly characteristics. For this purpose, the CIPN instrument combines active and passive neutron interrogation, along with passive gamma-ray measurements, to provide three independent observables. This paper describes the initial feasibility demonstration of the CIPN instrument, which involved measurements of four pressurized-water-reactor spent fuel assemblies with different levels of burnup and two initial enrichments. The measurements were performed at the Post-Irradiation Examination Facility at the Korea Atomic Energy Institute in the Republic of Korea. The key aim of the demonstration was to evaluate CIPN instrument performance under realistic deployment conditions, with the focus on a detailed assessment of systematic uncertainties that are best evaluated experimentally. The measurements revealed good positioning reproducibility, as well as a high degree of insensitivity of the CIPN instrument's response to irregularities in a radial burnup profile. Systematic uncertainty of individual CIPN instrument signals due to assembly rotation was found to be orientation in the instrument.

  5. Stratospheric carbonyl sulfide (OCS) burden

    Science.gov (United States)

    Kloss, Corinna; Walker, Kaley A.; Deshler, Terry; von Hobe, Marc

    2015-04-01

    An estimation of the global stratospheric burden of carbonyl sulfide (OCS) calculated using satellite based measurements from the Atmospheric Chemistry Experiment - Fourier Transform Spectrometer (ACE-FTS) will be presented. OCS is the most abundant sulfur containing gas in the atmosphere in the absence of volcanic eruptions. With a long lifetime of 2-6 years it reaches the stratosphere where it is photolyzed and the sulfur oxidized and condensed to aerosols, contributing to the stratospheric aerosol layer. The aerosol layer is the one factor of the middle-atmosphere with a direct impact on the Earth's climate by scattering incoming solar radiation back to space. Therefore it is crucial to understand and estimate the different processes and abundances of the species contributing to the aerosol layer. However, the exact amount of OCS in the stratosphere has not been quantified yet. A study on the OCS mixing ratio distribution based on ACE-FTS data has already been made by Barkley et al. (2008), also giving an estimation for the total atmospheric OCS mass. ACE-FTS is an infrared solar occultation spectrometer providing high- resolution profile observations since 2004. In the scope of this work the focus lies on the stratospheric OCS burden, calculated by integrating the ACE profiles. A global overview on the stratospheric OCS amount in the past and present based on the ACE data as well as a look at regional and seasonal variability will be given. Furthermore, the results of this work will be useful for further studies on OCS fluxes and lifetimes, and in quantifying the contribution of OCS to the global stratospheric sulfur burden. Barkley et al., 2008, Geophys. Res. Lett., 35, L14810.

  6. Terahertz spectroscopy of hydrogen sulfide

    International Nuclear Information System (INIS)

    Pure rotational transitions of hydrogen sulfide (H2S) in its ground and first excited vibrational states have been recorded at room temperature. The spectrum comprises an average of 1020 scans at 0.005 cm−1 resolution recorded in the region 45–360 cm−1 (1.4 to 10.5 THz) with a globar continuum source using a Fourier transform spectrometer located at the AILES beamline of the SOLEIL synchrotron. Over 2400 rotational lines have been detected belonging to ground vibrational state transitions of the four isotopologues H232S, H233S, H234S, and H236S observed in natural abundance. 65% of these lines are recorded and assigned for the first time, sampling levels as high as J=26 and Ka=17 for H232S. 320 pure rotational transitions of H232S in its first excited bending vibrational state are recorded and analysed for the first time and 86 transitions for H234S, where some of these transitions belong to new experimental energy levels. Rotational constants have been fitted for all the isotopologues in both vibrational states using a standard effective Hamiltonian approach. Comprehensive comparisons are made with previously available data as well as the data available in HITRAN, CDMS, and JPL databases. The 91 transitions assigned to H236S give the first proper characterization of its pure rotational spectrum. -- Highlights: • Over 2400 lines are measured and assigned in the 45–360 cm−1 region. • New rotational transitions are assigned for four isotopologues of H2S. • Rotational transitions within the first excited state of H2S are assigned for the first time. • An improved rotational line list is presented

  7. Sulfide capacities of fayalite-base slags

    Science.gov (United States)

    Simeonov, S. R.; Sridhar, R.; Toguri, J. M.

    1995-04-01

    The sulfide capacities of fayalite-base slags were measured by a gas-slag equilibration technique under controlled oxygen and sulfur potentials similar to those encountered in the pyrometallurgical processing of nonferrous metals. The oxygen pressure range was from 10-9.5 to 10-11 MPa and the sulfur pressure range from 10-3 to 10-4.5 MPa, over a temperature range of 1473 to 1623 K. The slags studied were FeO-SiO2 at silica saturation and those with addition of CaO, MgO, and Al2O3 to determine their effect on sulfide capacities. For these slags, the sulfide capacities were found to vary from 10-3.3 to 10-5. The sulfide capacities increased with increasing temperature from 1473 to 1623 K. A comparison of the reported plant data on sulfur content of industrial slags shows good agreement with the present experimental results. The present data will be useful in estimating metal losses in slag due to metal sulfide entrainment in nonferrous smelters.

  8. Synthesis of magnetic rhenium sulfide composite nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Tang Naimei [Division of Molecular and Materials Simulation, Key Lab for Nanomaterials, Ministry of Education, Beijing University of Chemical Technology, Beijing 100029 (China); Tu Weixia [Division of Molecular and Materials Simulation, Key Lab for Nanomaterials, Ministry of Education, Beijing University of Chemical Technology, Beijing 100029 (China)], E-mail: tuwx@mail.buct.edu.cn

    2009-10-15

    Rhenium sulfide nanoparticles are associated with magnetic iron oxide through coprecipitation of iron salts with tetramethylammonium hydroxide. Sizes of the formed magnetic rhenium sulfide composite particles are in the range 5.5-12.5 nm. X-ray diffraction and energy-dispersive analysis of X-rays spectra demonstrate the coexistence of Fe{sub 3}O{sub 4} and ReS{sub 2} in the composite particle, which confirm the formation of the magnetic rhenium sulfide composite nanoparticles. The association of rhenium sulfide with iron oxide not only keeps electronic state and composition of the rhenium sulfide nanoparticles, but also introduces magnetism with the level of 24.1 emu g{sup -1} at 14 kOe. Surface modification with monocarboxyl-terminated poly(ethylene glycol) (MPEG-COOH) has the role of deaggregating the composite nanoparticles to be with average hydrodynamic size of 27.3 nm and improving the dispersion and the stability of the composite nanoparticles in water.

  9. Transition Metal Catalyzed Synthesis of Aryl Sulfides

    Directory of Open Access Journals (Sweden)

    Chad C. Eichman

    2011-01-01

    Full Text Available The presence of aryl sulfides in biologically active compounds has resulted in the development of new methods to form carbon-sulfur bonds. The synthesis of aryl sulfides via metal catalysis has significantly increased in recent years. Historically, thiolates and sulfides have been thought to plague catalyst activity in the presence of transition metals. Indeed, strong coordination of thiolates and thioethers to transition metals can often hinder catalytic activity; however, various catalysts are able to withstand catalyst deactivation and form aryl carbon-sulfur bonds in high-yielding transformations. This review discusses the metal-catalyzed arylation of thiols and the use of disulfides as metal-thiolate precursors for the formation of C-S bonds.

  10. Sulfide and methane production in sewer sediments.

    Science.gov (United States)

    Liu, Yiwen; Ni, Bing-Jie; Ganigué, Ramon; Werner, Ursula; Sharma, Keshab R; Yuan, Zhiguo

    2015-03-01

    Recent studies have demonstrated significant sulfide and methane production by sewer biofilms, particularly in rising mains. Sewer sediments in gravity sewers are also biologically active; however, their contribution to biological transformations in sewers is poorly understood at present. In this study, sediments collected from a gravity sewer were cultivated in a laboratory reactor fed with real wastewater for more than one year to obtain intact sediments. Batch test results show significant sulfide production with an average rate of 9.20 ± 0.39 g S/m(2)·d from the sediments, which is significantly higher than the areal rate of sewer biofilms. In contrast, the average methane production rate is 1.56 ± 0.14 g CH4/m(2)·d at 20 °C, which is comparable to the areal rate of sewer biofilms. These results clearly show that the contributions of sewer sediments to sulfide and methane production cannot be ignored when evaluating sewer emissions. Microsensor and pore water measurements of sulfide, sulfate and methane in the sediments, microbial profiling along the depth of the sediments and mathematical modelling reveal that sulfide production takes place near the sediment surface due to the limited penetration of sulfate. In comparison, methane production occurs in a much deeper zone below the surface likely due to the better penetration of soluble organic carbon. Modelling results illustrate the dependency of sulfide and methane productions on the bulk sulfate and soluble organic carbon concentrations can be well described with half-order kinetics.

  11. Modeling of Sulfide Microenvironments on Mars

    Science.gov (United States)

    Schwenzer, S. P.; Bridges, J. C.; McAdam, A.; Steer, E. D.; Conrad, P. G.; Kelley, S. P.; Wiens, R. C.; Mangold, N.; Grotzinger, J.; Eigenbrode, J. L.; Franz, H. B.; Sutter, B.

    2016-01-01

    Yellowknife Bay (YKB; sol 124-198) is the second site that the Mars Science Laboratory Rover Curiosity investigated in detail on its mission in Gale Crater. YKB represents lake bed sediments from an overall neutral pH, low salinity environment, with a mineralogical composition which includes Ca-sulfates, Fe oxide/hydroxides, Fe-sulfides, amorphous material, and trioctahedral phyllosilicates. We investigate whether sulfide alteration could be associated with ancient habitable microenvironments in the Gale mudstones. Some textural evidence for such alteration may be pre-sent in the nodules present in the mudstone.

  12. Acute inhalation toxicity of carbonyl sulfide

    Energy Technology Data Exchange (ETDEWEB)

    Benson, J.M.; Hahn, F.F.; Barr, E.B. [and others

    1995-12-01

    Carbonyl sulfide (COS), a colorless gas, is a side product of industrial procedures sure as coal hydrogenation and gasification. It is structurally related to and is a metabolite of carbon disulfide. COS is metabolized in the body by carbonic anhydrase to hydrogen sulfide (H{sub 2}S), which is thought to be responsible for COS toxicity. No threshold limit value for COS has been established. Results of these studies indicate COS (with an LC{sub 50} of 590 ppm) is slightly less acutely toxic than H{sub 2}S (LC{sub 50} of 440 ppm).

  13. Sol-gel processing of metal sulfides

    Science.gov (United States)

    Stanic, Vesha

    Metal sulfides were synthesised via a sol-gel process using various metal alkoxides and hydrogen sulfide in toluene. Colloidal gels were prepared from germanium ethoxide, germanium isopropoxide, zinc tert-butoxide and tungsten (VI) ethoxide, whereas colloidal powder was produced from tungsten (V) dichloride ethoxide. Special precautions were necessary to protect the reaction mixture from water contamination which produced metal oxides. Results indicated that the main source of water is the hydrogen sulfide gas. In addition, synthesis of metal sulfides from a mixture of metal oxide and sulfide was demonstrated by the example of monoclinic germanium disulfide. It was produced by reaction of the sol-gel product with sulfur. Heat treatment of the sol-gel product and sulfur yielded single phase GeSsb2. The sol-gel prepared materials and their heat treated products were characterized by various methods. A chemical kinetics study of the functional groups -OR, -SH and Ssp{2-} was carried out for the sol-gel processing of GeSsb2 from of hydrogen sulfide and two different alkoxides, germanium ethoxide and germanium isopropoxide. The study was performed for different concentrations of precursors at different molar ratios and temperatures. The results indicate that the proposed reaction mechanism was simplified under appropriate reaction conditions. Experimentally determined rate constants of thiolysis and condensations demonstrate that thiolysis is slow and that condensations are fast steps, regardless of the studied reaction conditions. A study of the temperature effect on the reaction rate constant shows that it increases with temperature in accord with both Arrhenius law and transition-state theory. Activation energies, Esba, and activation parameters DeltaSsp{ddagger}, DeltaHsp{ddagger} and DeltaGsp{ddagger}, were determined for thiolysis and condensation reactions. The potentiometric tiration method was used for quantitative determination of germanium sulfide and

  14. Membrane for hydrogen recovery from streams containing hydrogen sulfide

    Science.gov (United States)

    Agarwal, Pradeep K.

    2007-01-16

    A membrane for hydrogen recovery from streams containing hydrogen sulfide is provided. The membrane comprises a substrate, a hydrogen permeable first membrane layer deposited on the substrate, and a second membrane layer deposited on the first layer. The second layer contains sulfides of transition metals and positioned on the on a feed side of the hydrogen sulfide stream. The present invention also includes a method for the direct decomposition of hydrogen sulfide to hydrogen and sulfur.

  15. Use of biogenic sulfide for ZnS precipitation

    NARCIS (Netherlands)

    Esposito, G.; Veeken, A.; Weijma, J.; Lens, P.N.L.

    2006-01-01

    A 600 ml continuously stirred tank reactor was used to assess the performance of a zinc sulfide precipitation process using a biogenic sulfide solution (the effluent of a sulfate-reducing bioreactor) as sulfide source. In all experiments, a proportional-integral (PI) control algorithm was used to co

  16. A physiologically based kinetic model for bacterial sulfide oxidation

    NARCIS (Netherlands)

    Klok, J.B.; Graaff, M. de; Bosch, P.L. van den; Boelee, N.C.; Keesman, K.J.; Janssen, A.J.W.M.

    2013-01-01

    In the biotechnological process for hydrogen sulfide removal from gas streams, a variety of oxidation products can be formed. Under natron-alkaline conditions, sulfide is oxidized by haloalkaliphilic sulfide oxidizing bacteria via flavocytochrome c oxidoreductase. From previous studies, it was concl

  17. T.O.C.S. : Hydrogen Sulfide Remission System

    OpenAIRE

    ECT Team, Purdue

    2007-01-01

    BioEnviroTech, Inc., (BET) developed Toxicity Odor Corrosion Sulfides (T.O.C.S.) Remission System for hydrogen sulfide reduction in municipal and industrial wastewater sewer, lift stations and force mains. This safe and cost effective biotreatment technology uses safe and natural bacteria to interrupt sulfide generation.

  18. Biological Efficiency of Californium-252 Source Evaluated by Comet Assay, Classical Cytogenetics and FISH in Human Lymphocytes Irradiated without and with BSH Pretreatment

    International Nuclear Information System (INIS)

    Biological effectiveness of californium-252 source was evaluated after irradiations in vitro of normal or pre-treated with compound enriched in B-10 ion cells. Peripheral blood lymphocytes were used as a model for human cells. DNA and chromosomal damage were studied to compare biological effectiveness of irradiation. Human blood samples or isolated lymphocytes were irradiated with the isotopic source of 252Cf, at the Faculty of Physics and Nuclear Techniques at the University of Mining and Metallurgy (both neutron source and samples were placed in ''infinite'' polyethylene block). Chemical pretreatment with Na210B12H11SH (BSH) was performed to introduce boron-10 ion into cells in order to check any enhancement effect due to the process of boron neutron capture. Single cell gel electrophoresis also known as the Comet assay was done to investigate the DNA damage. Classical cytogenetic analysis was applied to assess the frequencies of unstable aberrations (dicentrics, rings and a centric fragments). To evaluate the frequencies of stable aberrations the fluorescence in situ hybridisation (FISH) with probes for chromosomes 1, 4 (14.3% of the whole genome) was performed. Linear (or close to linear) increase with radiation dose were observed for the DNA damage and aberration frequencies in lymphocytes both untreated or pre-treated with BSH. Levels of translocations evaluated for the whole genome were comparable with the frequencies of dicentrics and rings. No significant differences were detected due to radiation dose in the frequencies of sister chromatid exchanges (SCE) detected in the second mitosis. No statistically significant differences were observed in various biological end-points between normal or boron pre-treated cells. (author)

  19. Measurement and biological significance of the volatile sulfur compounds hydrogen sulfide, methanethiol and dimethyl sulfide in various biological matrices

    NARCIS (Netherlands)

    Tangerman, Albert

    2009-01-01

    This review deals with the measurement of the volatile Sulfur compounds hydrogen sulfide, methanethiol and dimethyl sulfide in various biological matrices of rats and humans (blood, serum, tissues, urine, breath, feces and flatus). Hydrogen sulfide and methanethiol both contain the active thiol (-SH

  20. Measurement and biological significance of the volatile sulfur compounds hydrogen sulfide, methanethiol and dimethyl sulfide in various biological matrices.

    NARCIS (Netherlands)

    Tangerman, A.

    2009-01-01

    This review deals with the measurement of the volatile sulfur compounds hydrogen sulfide, methanethiol and dimethyl sulfide in various biological matrices of rats and humans (blood, serum, tissues, urine, breath, feces and flatus). Hydrogen sulfide and methanethiol both contain the active thiol (-SH

  1. Hydrogen Sulfide in Preeclampsia : Potential Therapeutic Implications

    NARCIS (Netherlands)

    Holwerda, Kim

    2015-01-01

    The thesis provide insights into the production and possible therapeutic effect of the gaseous molecule hydrogen sulfide (H2S) in preeclampsia (PE). H2S is an important molecule in the (human) body. It is among others involved in blood pressure regulation, stimulation of vascular growth and modulati

  2. Monitoring sulfide and sulfate-reducing bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Tanner, R.S.

    1995-12-31

    Simple yet precise and accurate methods for monitoring sulfate-reducing bacteria (SRB) and sulfide remain useful for the study of bacterial souring and corrosion. Test kits are available to measure sulfide in field samples. A more precise methylene blue sulfide assay for both field and laboratory studies is described here. Improved media, compared to that in API RP-38, for enumeration of SRB have been formulated. One of these, API-RST, contained cysteine (1.1 mM) as a reducing agent, which may be a confounding source of sulfide. While cysteine was required for rapid enumeration of SRB from environmental samples, the concentration of cysteine in medium could be reduced to 0.4 mM. It was also determined that elevated levels of yeast extract (>1 g/liter) could interfere with enumeration of SRB from environmental samples. The API-RST medium was modified to a RST-11 medium. Other changes in medium composition, in addition to reduction of cysteine, included reduction of the concentration of phosphate from 3.4 mM to 2.2 mM, reduction of the concentration of ferrous iron from 0.8 mM to 0.5 mM and preparation of a stock mineral solution to ease medium preparation. SRB from environmental samples could be enumerated in a week in this medium.

  3. The diagenesis of carbohydrates by hydrogen sulfide

    Science.gov (United States)

    Mango, Frank D.

    1983-08-01

    Carbohydrates react with hydrogen sulfide under low temperature (100° to 200°C) yielding a variety of organosulfur compounds including thiophenes, thiols, sulfides and sulfones. A polymer is also produced, whose elemental composition is within the range of natural coals. When reductive dehydration is carried out in the presence of hydrocarbon, organosulfur compounds are formed in the carbon number range of the hydrocarbon used. In these processes, an active hydrogen transfer catalyst is produced which facilitates the passage of hydrogen between normal paraffins and saccharide units, distributing sulfur between these two families primarily in the form of thiophene rings. The simplicity of these systems - H 2S, carbohydrates, H 2O, hydrocarbon - and the facility of the chemistry would suggest that the carbohydrates and hydrogen sulfide may be important agents in the diagenetic processes leading to petroleum and coal. Carbohydrate reduction by hydrogen sulfide may constitute an important route through which certain organosulfur compounds found in petroleum and coal entered these materials in early diagenesis.

  4. Recent findings on sinks for sulfide in gravity sewer networks

    DEFF Research Database (Denmark)

    Nielsen, Asbjørn Haaning; Hvitved-Jacobsen, Thorkild; Vollertsen, Jes

    2006-01-01

    Sulfide buildup in sewer networks is associated with several problems, including health impacts, corrosion of sewer structures and odor nuisance. In recent years, significant advances in the knowledge of the major processes governing sulfide buildup in sewer networks have been made. This paper...... summarizes this newly obtained knowledge and emphasizes important implications of the findings. Model simulations of the in-sewer processes important for the sulfur cycle showed that sulfide oxidation in the wetted biofilm is typically the most important sink for dissolved sulfide in gravity sewers. However......, sulfide emission and thereby potential hydrogen sulfide buildup in the sewer atmosphere is of particular importance in sewers constructed with large diameter pipes, in sewers constructed with steep slopes and in sewers conveying low pH wastewater. Precipitation of metal sulfides is only important when...

  5. Sulfide Intrusion and Detoxification in the Seagrass Zostera marina.

    Directory of Open Access Journals (Sweden)

    Harald Hasler-Sheetal

    Full Text Available Gaseous sulfide intrusion into seagrasses growing in sulfidic sediments causes little or no harm to the plant, indicating the presence of an unknown sulfide tolerance or detoxification mechanism. We assessed such mechanism in the seagrass Zostera marina in the laboratory and in the field with scanning electron microscopy coupled to energy dispersive X-ray spectroscopy, chromatographic and spectrophotometric methods, and stable isotope tracing coupled with a mass balance of sulfur compounds. We found that Z. marina detoxified gaseous sediment-derived sulfide through incorporation and that most of the detoxification occurred in underground tissues, where sulfide intrusion was greatest. Elemental sulfur was a major detoxification compound, precipitating on the inner wall of the aerenchyma of underground tissues. Sulfide was metabolized into thiols and entered the plant sulfur metabolism as well as being stored as sulfate throughout the plant. We conclude that avoidance of sulfide exposure by reoxidation of sulfide in the rhizosphere or aerenchyma and tolerance of sulfide intrusion by incorporation of sulfur in the plant are likely major survival strategies of seagrasses in sulfidic sediments.

  6. The Evolution of Sulfide Tolerance in the Cyanobacteria

    Science.gov (United States)

    Miller, Scott R.; Bebout, Brad M.; DeVincenzi, Donald L. (Technical Monitor)

    2000-01-01

    Understanding how the function of extant microorganisms has recorded both their evolutionary histories and their past interactions with the environment is a stated goal of astrobiology. We are taking a multidisciplinary approach to investigate the diversification of sulfide tolerance mechanisms in the cyanobacteria, which vary both in their degree of exposure to sulfide and in their capacity to tolerate this inhibitor of photosynthetic electron transport. Since conditions were very reducing during the first part of Earth's history and detrital sulfides have been found in Archean sediments, mechanisms conferring sulfide tolerance may have been important for the evolutionary success of the ancestors of extant cyanobacteria. Two tolerance mechanisms have been identified in this group: (1) resistance of photosystem II, the principal target of sulfide toxicity; and (2) maintenance of the ability to fix carbon despite photosystem II inhibition by utilizing sulfide as an electron donor in photosystem I - dependent, anoxygenic photosynthesis. We are presently collecting comparative data on aspects of sulfide physiology for laboratory clones isolated from a variety of habitats. These data will be analyzed within a phylogenetic framework inferred from molecular sequence data collected for these clones to test how frequently different mechanisms of tolerance have evolved and which tolerance mechanism evolved first. In addition, by analyzing these physiological data together with environmental sulfide data collected from our research sites using microelectrodes, we can also test whether the breadth of an organism's sulfide tolerance can be predicted from the magnitude of variation in environmental sulfide concentration it has experienced in its recent evolutionary past and whether greater average sulfide concentration and/or temporal variability in sulfide favors the evolution of a particular mechanism of sulfide tolerance.

  7. Iron-sulfide redox flow batteries

    Energy Technology Data Exchange (ETDEWEB)

    Xia, Guanguang; Yang, Zhenguo; Li, Liyu; Kim, Soowhan; Liu, Jun; Graff, Gordon L

    2016-06-14

    Iron-sulfide redox flow battery (RFB) systems can be advantageous for energy storage, particularly when the electrolytes have pH values greater than 6. Such systems can exhibit excellent energy conversion efficiency and stability and can utilize low-cost materials that are relatively safer and more environmentally friendly. One example of an iron-sulfide RFB is characterized by a positive electrolyte that comprises Fe(III) and/or Fe(II) in a positive electrolyte supporting solution, a negative electrolyte that comprises S.sup.2- and/or S in a negative electrolyte supporting solution, and a membrane, or a separator, that separates the positive electrolyte and electrode from the negative electrolyte and electrode.

  8. Speciation of arsenic in sulfidic waters

    Directory of Open Access Journals (Sweden)

    Ford Robert G

    2003-03-01

    Full Text Available Formation constants for thioarsenite species have been determined in dilute solutions at 25°C, ΣH2S from 10-7.5 to 10-3.0 M, ΣAs from 10-5.6 to 10-4.8 M, and pH 7 and 10. The principal inorganic arsenic species in anoxic aquatic systems are arsenite, As(OH30, and a mononuclear thioarsenite with an S/As ratio of 3:1. Thioarsenic species with S/As ratios of 1 : 1,2 : 1, and 4 : 1 are lesser components in sulfidic solutions that might be encountered in natural aquatic environments. Thioarsenites dominate arsenic speciation at sulfide concentrations > 10-4.3 M at neutral pH. Conversion from neutral As(OH30 to anionic thioarsenite species may regulate the transport and fate of arsenic in sulfate-reducing environments by governing sorption and mineral precipitation reactions.

  9. Iron-sulfide redox flow batteries

    Energy Technology Data Exchange (ETDEWEB)

    Xia, Guan-Guang; Yang, Zhenguo; Li, Liyu; Kim, Soowhan; Liu, Jun; Graff, Gordon L

    2013-12-17

    Iron-sulfide redox flow battery (RFB) systems can be advantageous for energy storage, particularly when the electrolytes have pH values greater than 6. Such systems can exhibit excellent energy conversion efficiency and stability and can utilize low-cost materials that are relatively safer and more environmentally friendly. One example of an iron-sulfide RFB is characterized by a positive electrolyte that comprises Fe(III) and/or Fe(II) in a positive electrolyte supporting solution, a negative electrolyte that comprises S.sup.2- and/or S in a negative electrolyte supporting solution, and a membrane, or a separator, that separates the positive electrolyte and electrode from the negative electrolyte and electrode.

  10. Subsurface heaters with low sulfidation rates

    Energy Technology Data Exchange (ETDEWEB)

    John, Randy Carl; Vinegar, Harold J

    2013-12-10

    A system for heating a hydrocarbon containing formation includes a heater having an elongated ferromagnetic metal heater section. The heater is located in an opening in a formation. The heater section is configured to heat the hydrocarbon containing formation. The exposed ferromagnetic metal has a sulfidation rate that goes down with increasing temperature of the heater, when the heater is in a selected temperature range.

  11. Efficiently Dispersing Carbon Nanotubes in Polyphenylene Sulfide

    OpenAIRE

    Sommer, Kevin M; Pipes, R. Byron

    2013-01-01

    Thermal plastics are replacing conventional metals in the aerospace, sporting, electronics, and other industries. Thermal plastics are able to withstand relatively high temperatures, have good fatigue properties, and are lighter than metals. Unfortunately, they are not very electrically conductive. However, adding carbon nanotubes to thermal plastics such as polyphenylene sulfide (PPS) can drastically increase the plastic's conductivity at a low weight percent of nanotubes called the percolat...

  12. Hydrogen sulfide prodrugs—a review

    Directory of Open Access Journals (Sweden)

    Yueqin Zheng

    2015-09-01

    Full Text Available Hydrogen sulfide (H2S is recognized as one of three gasotransmitters together with nitric oxide (NO and carbon monoxide (CO. As a signaling molecule, H2S plays an important role in physiology and shows great potential in pharmaceutical applications. Along this line, there is a need for the development of H2S prodrugs for various reasons. In this review, we summarize different H2S prodrugs, their chemical properties, and some of their potential therapeutic applications.

  13. Hydrogen sulfide prodrugs—a review

    Science.gov (United States)

    Zheng, Yueqin; Ji, Xingyue; Ji, Kaili; Wang, Binghe

    2015-01-01

    Hydrogen sulfide (H2S) is recognized as one of three gasotransmitters together with nitric oxide (NO) and carbon monoxide (CO). As a signaling molecule, H2S plays an important role in physiology and shows great potential in pharmaceutical applications. Along this line, there is a need for the development of H2S prodrugs for various reasons. In this review, we summarize different H2S prodrugs, their chemical properties, and some of their potential therapeutic applications. PMID:26579468

  14. Microaeration for hydrogen sulfide removal in UASB reactor.

    Science.gov (United States)

    Krayzelova, Lucie; Bartacek, Jan; Kolesarova, Nina; Jenicek, Pavel

    2014-11-01

    The removal of hydrogen sulfide from biogas by microaeration was studied in Up-flow Anaerobic Sludge Blanket (UASB) reactors treating synthetic brewery wastewater. A fully anaerobic UASB reactor served as a control while air was dosed into a microaerobic UASB reactor (UMSB). After a year of operation, sulfur balance was described in both reactors. In UASB, sulfur was mainly presented in the effluent as sulfide (49%) and in biogas as hydrogen sulfide (34%). In UMSB, 74% of sulfur was detected in the effluent (41% being sulfide and 33% being elemental sulfur), 10% accumulated in headspace as elemental sulfur and 9% escaped in biogas as hydrogen sulfide. The efficiency of hydrogen sulfide removal in UMSB was on average 73%. Microaeration did not cause any decrease in COD removal or methanogenic activity in UMSB and the elemental sulfur produced by microaeration did not accumulate in granular sludge. PMID:25270045

  15. Sulfide scaling in low enthalpy geothermal environments; A survey

    Energy Technology Data Exchange (ETDEWEB)

    Criaud, A.; Fouillac, C. (Bureau de Recherches Geologiques et Minieres (BRGM), 45 - Orleans (France))

    1989-01-01

    A review of the sulfide scaling phenomena in low-temperature environments is presented. While high-temperature fluids tend to deposit metal sulfides because of their high concentrations of dissolved metals and variations of temperature, pressure and fluid chemistry, low temperature media are characterized by very low metal content but much higher dissolved sulfide. In the case of the goethermal wells of the Paris Basin, detailed studies demonstrate that the relatively large concentrations of chloride and dissolved sulfide are responsible for corrosion and consequent formation of iron sulfide scale composed of mackinawite, pyrite and pyrrhotite. The effects of the exploitation schemes are far less important than the corrosion of the casings. The low-enthalpy fluids that do not originate from sedimentary aquifers (such as in Iceland and Bulgaria), have a limited corrosion potential, and the thin sulfide film that appears may prevent the progress of corrosion.

  16. Oxidation and Precipitation of Sulfide in Sewer Networks

    DEFF Research Database (Denmark)

    Nielsen, A. H.

    for the accumulation of metal sulfides in the biofilms. This was the case even when the iron concentration in the wastewater was increased approximately ten times compared to the in situ concentration. In aerobic biofilms, iron precipitation was apparently controlled by phosphate. Based on the experimental studies...... were studied in both wastewater and biofilms. Particular emphasis was on the importance of iron in the sulfur cycle. Iron is typically among the dominant metals in wastewater. The experiments showed that, ferric iron (Fe(III)) that was added to anaerobic wastewater was rapidly reduced to ferrous iron...... (Fe(II)) and precipitated subsequently with dissolved sulfide as ferrous sulfide (FeS). The ferrous sulfide precipitation was relatively fast, but not immediate. Despite the very low solubility of ferrous sulfide, initially present iron did not react completely with sulfide. This observation...

  17. INVESTIGATIONS ON BIOCHEMICAL PURIFICATION OF GROUND WATER FROM HYDROGEN SULFIDE

    OpenAIRE

    Yu. P. Sedlukho; Yu. O. Stankevich

    2015-01-01

    The paper considers problems and features of biochemical removal of hydrogen sulfide from ground water. The analysis of existing methods for purification of ground water from hydrogen sulfide has been given in the paper. The paper has established shortcomings of physical and chemical purification of ground water. While using aeration methods for removal of hydrogen sulfide formation of colloidal sulfur that gives muddiness and opalescence to water occurs due to partial chemical air oxidation....

  18. Extraction of Nanosized Cobalt Sulfide from Spent Hydrocracking Catalyst

    OpenAIRE

    Samia A. Kosa; Hegazy, Eman Z.

    2013-01-01

    The processes used for the extraction of metals (Co, Mo, and Al) from spent hydrotreating catalysts were investigated in this study. A detailed mechanism of the metal extraction process is described. Additionally, a simulation study was performed to understand the sulfidizing mechanism. The suggested separation procedure was effective and achieved an extraction of approximately 80–90%. In addition, the sulfidization mechanism was identified. This sulfidizing process for Co was found to involv...

  19. Limitation of Sulfide Capacity Concept for Molten Slags

    Science.gov (United States)

    Jung, In-Ho; Moosavi-Khoonsari, Elmira

    2016-04-01

    The sulfide capacity concept has been widely used in pyrometallurgy to define sulfur removal capacities of slags. Typically, the sulfide capacity is considered to be a unique slag property depending only on temperature regardless of partial pressures of oxygen and sulfur. In the present study, it is demonstrated that sulfide capacities of slags in particular those of Na2O-containing slags can vary with partial pressures of oxygen and sulfur due to large solubility of sulfide in Na2O-containing slag systems.

  20. Influence of iron on sulfide inhibition in dark biohydrogen fermentation.

    Science.gov (United States)

    Dhar, Bipro Ranjan; Elbeshbishy, Elsayed; Nakhla, George

    2012-12-01

    Sulfide impact on biohydrogen production using dark fermentation of glucose at 37 °C was investigated. Dissolved sulfide (S(2-)) at a low concentration (25mg/L) increased biohydrogen production by 54% relative to the control (without iron addition). Whereas on initial dissolved S(2-) concentration of 500 mg/L significantly inhibited the biohydrogen production with total cumulative biohydrogen decreasing by 90% compared to the control (without iron addition). At sulfide concentrations of 500 mg S(2-)/L, addition of Fe(2+) at 3-4 times the theoretical requirement to precipitate 100% of the dissolved S(2-) entirely eliminated the inhibitory effect of sulfide.

  1. MEASURING METAL SULFIDE COMPLEXES IN OXIC RIVER WATERS WITH SQUARE WAVE VOLTAMMETRY. (R825395)

    Science.gov (United States)

    A sulfide identification protocol was developed to quantify specific metal sulfides that could exist in river water. Using a series of acid additions, nitrogen purges, and voltammetric analyses, metal sulfides were identified and semiquantified in three specific gr...

  2. Modeling Sulfides, pH and Hydrogen Sulfide Gas in the Sewers of San Francisco

    DEFF Research Database (Denmark)

    Vollertsen, Jes; Revilla, Nohemy; Hvitved-Jacobsen, Thorkild;

    2015-01-01

    An extensive measuring campaign targeted on sewer odor problems was undertaken in San Francisco. It was assessed whether a conceptual sewer process model could reproduce the measured concentrations of total sulfide in the wastewater and H2S gas in the sewer atmosphere, and to which degree...

  3. Solubility of hydrogen sulfide in water

    International Nuclear Information System (INIS)

    The solubility of hydrogen sulfide in water, which is of importance in the design and analysis of the dual temperature process for the production of heavy water, has been measured in the temperature range 100 - 1800C at pressures up to 6670 kPa or the hydrate/H2S-rich liquid locus, whichever is lower at the particular temperature. Limited vapor phase data at 900, 1200, and 1500C were also obtained. Henry's coefficients have been determined from the experimental data. (orig./HK)

  4. Oxidation of Reduced Sulfur Species: Carbonyl Sulfide

    DEFF Research Database (Denmark)

    Glarborg, Peter; Marshall, Paul

    2013-01-01

    A detailed chemical kinetic model for oxidation of carbonyl sulfide (OCS) has been developed, based on a critical evaluation of data from the literature. The mechanism has been validated against experimental results from batch reactors, flow reactors, and shock tubes. The model predicts...... satisfactorily oxidation of OCS over a wide range of stoichiometric air–fuel ratios (0.5 ≤λ≤7.3), temperatures (450–1700 K), and pressures (0.02–3.0 atm) under dry conditions. The governing reaction mechanisms are outlined based on calculations with the kinetic model. The oxidation rate of OCS is controlled...

  5. Normal State of the Metallic Hydrogen Sulfide

    OpenAIRE

    Kudryashov, Nikolay A.; Kutukov, Alexander A.; Mazur, Evgeny A.

    2016-01-01

    Generalized theory of the normal properties of the metal in the case of the electron-phonon (EP) systems with not constant density of electronic states is used to examine the normal state of the SH3 and SH2 phase of the hydrogen sulfide at different pressures. The frequency dependence of the real and imaginary part of the self-energy part (SP) of the electron Green's function, the real and imaginary part of the complex renormalization of the electron mass, the real and imaginary part of the c...

  6. 21 CFR 73.2995 - Luminescent zinc sulfide.

    Science.gov (United States)

    2010-04-01

    ... coloring externally applied facial makeup preparations and nail polish included under § 720.4(c)(7)(ix) and... zinc sulfide in facial makeup preparations shall not exceed 10 percent by weight of the final product. (2) Facial makeup preparations containing luminescent zinc sulfide are intended for use only...

  7. Effect of Soluble Sulfide on the Activity of Luminescent Bacteria

    Directory of Open Access Journals (Sweden)

    Feng Wang

    2012-05-01

    Full Text Available Sulfide is an important water pollutant widely found in industrial waste water that has attracted much attention. S2−, as a weak acidic anion, is easy hydrolyzed to HS and H2S in aqueous solution. In this study, biological tests were performed to establish the toxicity of sulfide solutions on luminescent bacteria. Considering the sulfide solution was contained three substances—S2−, HS and H2S—the toxicity test was performed at different pH values to investigate which form of sulfide increased light emission and which reduced light emission. It was shown that the EC50 values were close at pH 7.4, 8.0 and 9.0 which were higher than pH 5 and 10. The light emission and sulfide concentrations displayed an inverse exponential dose-response relationship within a certain concentration range at pH 5, 6.5 and 10. The same phenomenon occurred for the high concentration of sulfide at pH 7.4, 8 and 9, in which the concentration of sulfide was HS >> H2S > S2−. An opposite hormesis-effect appeared at the low concentrations of sulfide.

  8. Hydrogen sulfide: physiological properties and therapeutic potential in ischaemia.

    Science.gov (United States)

    Bos, Eelke M; van Goor, Harry; Joles, Jaap A; Whiteman, Matthew; Leuvenink, Henri G D

    2015-03-01

    Hydrogen sulfide (H2 S) has become a molecule of high interest in recent years, and it is now recognized as the third gasotransmitter in addition to nitric oxide and carbon monoxide. In this review, we discuss the recent literature on the physiology of endogenous and exogenous H2 S, focusing upon the protective effects of hydrogen sulfide in models of hypoxia and ischaemia.

  9. 40 CFR 425.03 - Sulfide analytical methods and applicability.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 29 2010-07-01 2010-07-01 false Sulfide analytical methods and applicability. 425.03 Section 425.03 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... § 425.03 Sulfide analytical methods and applicability. (a) The potassium ferricyanide titration...

  10. Hydrogen Sulfide and Polysulfides as Biological Mediators

    Directory of Open Access Journals (Sweden)

    Hideo Kimura

    2014-10-01

    Full Text Available Hydrogen sulfide (H2S is recognized as a biological mediator with various roles such as neuromodulation, regulation of the vascular tone, cytoprotection, anti-inflammation, oxygen sensing, angiogenesis, and generation of mitochondrial energy. It is produced by cystathionine β-synthase (CBS, cystathionine γ-lyase (CSE, and 3-mercaptopyruvate sulfurtransferase (3MST. The activity of CBS is enhanced by S-adenosyl methionine (SAM and glutathionylation, while it is inhibited by nitric oxide (NO and carbon monoxide (CO. The activity of CSE and cysteine aminotransferase (CAT, which produces the 3MST substrate 3-mercaptopyruvate (3MP, is regulated by Ca2+. H2S is oxidized to thiosulfate in mitochondria through the sequential action of sulfide quinone oxidoreductase (SQR, sulfur dioxygenase, and rhodanese. The rates of the production and clearance of H2S determine its cellular concentration. Polysulfides (H2Sn have been found to occur in the brain and activate transient receptor potential ankyrin 1 (TRPA1 channels, facilitate the translocation of nuclear factor erythroid 2-related factor 2 (Nrf2 to the nucleus, and suppress the activity of phosphatase and tensin homolog (PTEN by sulfurating (sulfhydrating the target cysteine residues. A cross talk between H2S and NO also plays an important role in cardioprotection as well as regulation of the vascular tone. H2S, polysulfides, and their cross talk with NO may mediate various physiological and pathophysiological responses.

  11. Calculation of sulfide capacities of multicomponent slags

    Science.gov (United States)

    Pelton, Arthur D.; Eriksson, Gunnar; Romero-Serrano, Antonio

    1993-10-01

    The Reddy-Blander model for the sulfide capacities of slags has been modified for the case of acid slags and to include A12O3 and TiO2 as components. The model has been extended to calculate a priori sulfide capacities of multicomponent slags, from a knowledge of the thermodynamic activities of the component oxides, with no adjustable parameters. Agreement with measurements is obtained within experimental uncertainty for binary, ternary, and quinary slags involving the components SiO2-Al2O3-TiO2-CaO-MgO-FeO-MnO over wide ranges of composition. The oxide activities used in the computations are calculated from a database of model parameters obtained by optimizing thermodynamic and phase equilibrium data for oxide systems. Sulfur has now been included in this database. A computing system with automatic access to this and other databases has been developed to permit the calculation of the sulfur content of slags in multicomponent slag/metal/gas/solid equilibria.

  12. First detection of doubly deuterated hydrogen sulfide

    CERN Document Server

    Vastel, C; Ceccarelli, C; Pearson, J

    2003-01-01

    This work was carried out with using the Caltech Submillimeter Observatory and presents the observational study of HDS and D2S towards a sample of Class 0 sources, and dense cores. We report the first detection of doubly deuterated hydrogen sulfide (D2S) in two dense cores and analyze the chemistry of these molecules aiming to help understand the deuteration processes in the interstellar medium. The observed values of the D2S/HDS ratio, and upper limits, require an atomic D/H ratio in the accreting gas of 0.1-1. The study presented in this Letter supports the hypothesis that formaldehyde, methanol and hydrogen sulfide are formed on the grain surfaces, during the cold pre-stellar core phase, where the CO depleted gas has large atomic D/H ratios. The high values for the D/H ratios are consistent with the predictions of a recent gas-phase chemical model that includes H3+ and its deuterated isotopomers, H2D+, D2H+ and D3+ (Roberts et al. 2003).

  13. Hierarchical Architecturing for Layered Thermoelectric Sulfides and Chalcogenides

    Directory of Open Access Journals (Sweden)

    Priyanka Jood

    2015-03-01

    Full Text Available Sulfides are promising candidates for environment-friendly and cost-effective thermoelectric materials. In this article, we review the recent progress in all-length-scale hierarchical architecturing for sulfides and chalcogenides, highlighting the key strategies used to enhance their thermoelectric performance. We primarily focus on TiS2-based layered sulfides, misfit layered sulfides, homologous chalcogenides, accordion-like layered Sn chalcogenides, and thermoelectric minerals. CS2 sulfurization is an appropriate method for preparing sulfide thermoelectric materials. At the atomic scale, the intercalation of guest atoms/layers into host crystal layers, crystal-structural evolution enabled by the homologous series, and low-energy atomic vibration effectively scatter phonons, resulting in a reduced lattice thermal conductivity. At the nanoscale, stacking faults further reduce the lattice thermal conductivity. At the microscale, the highly oriented microtexture allows high carrier mobility in the in-plane direction, leading to a high thermoelectric power factor.

  14. Effect of palladium on sulfide tarnishing of noble metal alloys.

    Science.gov (United States)

    Suoninen, E; Herø, H; Minni, E

    1985-10-01

    Electron spectroscopic studies of Au-Ag-Cu alloys of the type used for dental castings show that small additions (less than or equal to 3 wt%) of palladium reduce essentially the thickness of the sulfide layer formed on surfaces of samples treated in aqueous Na2S solutions. Relative to silver, palladium does not enrich in the sulfide, but statistically significant enrichment is found immediately below the sulfide layer. This enrichment probably takes place during the exposure of the substrate surface to atmosphere before the sulfiding treatment. The mechanism of the impeding effect of palladium on sulfiding is assumed to be a decrease in diffusion from the bulk alloy to the surface due to the enriched layer. The effect cannot be explained by changes in the electronic structure of the alloy due to palladium alloying.

  15. Influence of Water Salinity on Air Purification from Hydrogen Sulfide

    Directory of Open Access Journals (Sweden)

    Leybovych L.I.

    2015-12-01

    Full Text Available Mathematical modeling of «sliding» water drop motion in the air flow was performed in software package FlowVision. The result of mathematical modeling of water motion in a droplet with diameter 100 microns at the «sliding» velocity of 15 m/s is shown. It is established that hydrogen sulfide oxidation occurs at the surface of phases contact. The schematic diagram of the experimental setup for studying air purification from hydrogen sulfide is shown. The results of the experimental research of hydrogen sulfide oxidation by tap and distilled water are presented. The dependence determining the share of hydrogen sulfide oxidized at the surface of phases contact from the dimensionless initial concentration of hydrogen sulfide in the air has been obtained.

  16. DISSOLUTION OF PLUTONIUM CONTAINING CARRIER PRECIPITATE BY CARBONATE METATHESIS AND SEPARATION OF SULFIDE IMPURITIES THEREFROM BY SULFIDE PRECIPITATION

    Science.gov (United States)

    Duffield, R.B.

    1959-07-14

    A process is described for recovering plutonium from foreign products wherein a carrier precipitate of lanthanum fluoride containing plutonium is obtained and includes the steps of dissolving the carrier precipitate in an alkali metal carbonate solution, adding a soluble sulfide, separating the sulfide precipitate, adding an alkali metal hydroxide, separating the resulting precipitate, washing, and dissolving in a strong acid.

  17. Californium Recovery from Palladium Wire

    Energy Technology Data Exchange (ETDEWEB)

    Burns, Jon D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2014-08-01

    The recovery of 252Cf from palladium-252Cf cermet wires was investigated to determine the feasibility of implementing it into the cermet wire production operation at Oak Ridge National Laboratory’s Radiochemical Engineering Development Center. The dissolution of Pd wire in 8 M HNO3 and trace amounts of HCl was studied at both ambient and elevated temperatures. These studies showed that it took days to dissolve the wire at ambient temperature and only 2 hours at 60°C. Adjusting the ratio of the volume of solvent to the mass of the wire segment showed little change in the kinetics of dissolution, which ranged from 0.176 mL/mg down to 0.019 mL/mg. A successful chromatographic separation of 153Gd, a surrogate for 252Cf, from Pd was demonstrated using AG 50x8 cation exchange resin with a bed volume of 0.5 mL and an internal diameter of 0.8 cm.

  18. Synthesis of Diaryl Ethers, Diaryl Sulfides, Heteroaryl Ethers and Heteroaryl Sulfides under Microwave Heating

    Institute of Scientific and Technical Information of China (English)

    LI,Feng; ZOU,Jiong; WANG,Quan-Rui; TAO,Feng-Gang

    2004-01-01

    @@ Diaryl ether moiety is found in a pool of naturally occurring and medicinally important compounds.[1] As a consequent, considerable efforts have been devoted to the assembly of this framework.[2] Recently, we have developed a microwave heating version of the synthesis of diaryl ethers as well as aryl sulfides. Under our conditions, even the extremely electron-poor 4-nitrophenol works well and its reaction with 1-halo-4-nitrobenzenes produces 4-(nitrophenoxy)-benzonitriles in satisfactory yield. The scope of the present protocol has been expanded to hydroxylated six-membered heterocycles as well as 2-pyrimidinethiol with mildly activated aryl halides, affording heteroaryl ethers and respectively sulfides. The advantages of the present method include the wide substrate scope, no use of any metal catalysts, the ease of product isolation and high yields.

  19. Atomic layer deposition of aluminum sulfide thin films using trimethylaluminum and hydrogen sulfide

    International Nuclear Information System (INIS)

    Sequential exposures of trimethylaluminum and hydrogen sulfide are used to deposit aluminum sulfide thin films by atomic layer deposition (ALD) in the temperature ranging from 100 to 200 °C. Growth rate of 1.3 Å per ALD cycle is achieved by in-situ quartz crystal microbalance measurements. It is found that the growth rate per ALD cycle is highly dependent on the purging time between the two precursors. Increased purge time results in higher growth rate. Surface limited chemistry during each ALD half cycle is studied by in-situ Fourier transformed infrared vibration spectroscopy. Time of flight secondary ion-mass spectroscopy measurement is used to confirm elemental composition of the deposited films

  20. Banded sulfide-magnetite ores of Mauk copper massive sulfide deposit, Central Urals: Composition and genesis

    Science.gov (United States)

    Safina, N. P.; Maslennikov, V. V.; Maslennikova, S. P.; Kotlyarov, V. A.; Danyushevsky, L. V.; Large, R. R.; Blinov, I. A.

    2015-05-01

    The results of investigation of metamorphosed sulfide-magnetite ores from the Mauk deposit located within the Main Ural Fault at the junction of Tagil and Magnitogorsk massive sulfide zones are discussed. The ore-hosting sequence comprises metamorphic rocks formed from basalt, carbonaceous and carbonaceous-cherty siltstone, and lenticular serpentinized ultramafic bodies. The ores of the deposit are represented by banded varieties and less frequent breccia. The clastic origin of the banded ore is indicated by load casts at the bottom of sulfide beds, alternation of sulfide and barren beds, and the truncation of the growth zones of pyrite crystals. Pyrite, pyrrhotite, chalcopyrite, sphalerite, and magnetite are the major minerals of the banded ores. The internal structure of the listed minerals testifies to the deep metamorphic recrystallization of primary hydrothermal-sedimentary ores accompanied with deformation. Cubanite, pyrrhotite, mackinawite, greigite, and gold are enclosed in metacrysts of pyrite, magnetite, and chalcopyrite. The accessory minerals of the Pb-Bi-Te, Bi-Te, and Ag-Te systems as well as uraninite have been found at the Mauk deposit for the first time. Magnetite predominantly replaces pyrite and less frequently chalcopyrite, pyrrhotite, and gangue minerals. It was established that the major carriers of As and Co are crystals of metamorphic pyrite. Chalcopyrite is the major carrier of Zn, Sn, Te, Pb, Bi, and Ag. Admixture of Fe and Cu is typical of sphalerite, and Se and Ni are characteristic of pyrrhotite. Ti, V, Mn, Sb, As, Ba, and U are concentrated in magnetite. The banded ores of the Mauk deposit are suggested as having been transformed in several stages: diagenesis, anadiagenesis, epidiagenesis ( t 500°C).

  1. Azo dye decolorization assisted by chemical and biogenic sulfide

    Energy Technology Data Exchange (ETDEWEB)

    Prato-Garcia, Dorian [Laboratory for Research on Advanced Processes for Water Treatment, Unidad Académica Juriquilla, Instituto de Ingeniería, Universidad Nacional Autónoma de México, Blvd. Juriquilla 3001, Querétaro 76230 (Mexico); Cervantes, Francisco J. [División de Ciencias Ambientales, Instituto Potosino de Investigación Científica y Tecnológica, Camino a la Presa de San José 2055, San Luis Potosí 78216 (Mexico); Buitrón, Germán, E-mail: gbuitronm@ii.unam.mx [Laboratory for Research on Advanced Processes for Water Treatment, Unidad Académica Juriquilla, Instituto de Ingeniería, Universidad Nacional Autónoma de México, Blvd. Juriquilla 3001, Querétaro 76230 (Mexico)

    2013-04-15

    Highlights: ► Azo dyes were reduced efficiently by chemical and biogenic sulfide. ► Biogenic sulfide was more efficient than chemical sulfide. ► There was no competition between dyes and sulfate for reducing equivalents. ► Aromatic amines barely affected the sulfate-reducing process. -- Abstract: The effectiveness of chemical and biogenic sulfide in decolorizing three sulfonated azo dyes and the robustness of a sulfate-reducing process for simultaneous decolorization and sulfate removal were evaluated. The results demonstrated that decolorization of azo dyes assisted by chemical sulfide and anthraquinone-2,6-disulfonate (AQDS) was effective. In the absence of AQDS, biogenic sulfide was more efficient than chemical sulfide for decolorizing the azo dyes. The performance of sulfate-reducing bacteria in attached-growth sequencing batch reactors suggested the absence of competition between the studied azo dyes and the sulfate-reducing process for the reducing equivalents. Additionally, the presence of chemical reduction by-products had an almost negligible effect on the sulfate removal rate, which was nearly constant (94%) after azo dye injection.

  2. Azo dye decolorization assisted by chemical and biogenic sulfide

    International Nuclear Information System (INIS)

    Highlights: ► Azo dyes were reduced efficiently by chemical and biogenic sulfide. ► Biogenic sulfide was more efficient than chemical sulfide. ► There was no competition between dyes and sulfate for reducing equivalents. ► Aromatic amines barely affected the sulfate-reducing process. -- Abstract: The effectiveness of chemical and biogenic sulfide in decolorizing three sulfonated azo dyes and the robustness of a sulfate-reducing process for simultaneous decolorization and sulfate removal were evaluated. The results demonstrated that decolorization of azo dyes assisted by chemical sulfide and anthraquinone-2,6-disulfonate (AQDS) was effective. In the absence of AQDS, biogenic sulfide was more efficient than chemical sulfide for decolorizing the azo dyes. The performance of sulfate-reducing bacteria in attached-growth sequencing batch reactors suggested the absence of competition between the studied azo dyes and the sulfate-reducing process for the reducing equivalents. Additionally, the presence of chemical reduction by-products had an almost negligible effect on the sulfate removal rate, which was nearly constant (94%) after azo dye injection

  3. Sulfide elimination by intermittent nitrate dosing in sewer sediments

    Institute of Scientific and Technical Information of China (English)

    Yanchen Liu; Chen Wu; Xiaohong Zhou; David Z.Zhu; Hanchang Shi

    2015-01-01

    The formation of hydrogen sulfide in biofilms and sediments in sewer systems can cause severe pipe corrosions and health hazards,and requires expensive programs for its prevention.The aim of this study is to propose a new control strategy and the optimal condition for sulfide elimination by intermittent nitrate dosing in sewer sediments.The study was carried out based on lab-scale experiments and batch tests using real sewer sediments.The intermittent nitrate dosing mode and the optimal control condition were investigated.The results indicated that the sulfide-intermittent-elimination strategy by nitrate dosing is advantageous for controlling sulfide accumulation in sewer sediment.The oxidation-reduction potential is a sensitive indicator parameter that can reflect the control effect and the minimum N/S (nitrate/sulfide)ratio with slight excess nitrate is necessary for optimal conditions ofefficient sulfide control with lower carbon source loss.The opth-nal control condition is feasible for the sulfide elimination in sewer systems.

  4. On the pelletizing of sulfide molybdenite concentrate

    International Nuclear Information System (INIS)

    Investigation results are discussed on the process of pelletizing with the use of various binders (water, syrup, sulfite-alcoholic residue and bentonite) for flotation sulfide molybdenite concentrate (∼84 % MoS2) of the Mongolian deposit. It is established that with the use of syrup rather strong pellets (>300 g/p) of desired size (2-3 mm) can be obtained at a binder flowrate of 1 kg per 100 kg of concentrate. The main advantage of using syrup instead of bentonite lies in the fact that in this instance no depletion of a molybdenum calcine obtained by oxidizing roasting of raw ore takes place due to syrup complete burning out. This affects positively subsequent hydrometallurgical conversion because of decreasing molybdenum losses with waste cakes

  5. Effect of radiation on wettability and floatability of sulfide minerals

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The feasibility for modifying the wettability and floatability of sulfide minerals by electron beam irradiation has been studied experimentally. The wettability of crystalline pyrite and floatability of some sulfide as pyrite, arsenopyrite, chalcopyrite and marmatite after irradiation were examined by flotation in a modified Hallimond tube. Experimental results show that the hydrophobicity of crystalline pyrite enhances with the increase of irradiation dose in a low dose range. And the flotation responses of sulfide minerals on irradiation dosevary with the mineral species and particle size. The floatability of minerals can be regulated by altering irradiation dose. An explanationfor the mechanism has been suggested based on the principle of radiation chemistry.

  6. Sulfide capacities of MnO-SiO2 slags

    Science.gov (United States)

    Reddy, Ramana G.; Blander, Milton

    1989-04-01

    Sulfide capacities of binary MnO-SiO2 slags at 1773 and 1923 K were calculated thermodynamically. Only known data, such as the standard free energy of formation of MnO and MnS and activities of MnO in the melt, are used in making calculations based on fundamental concepts. Excellent agreement is found between our calculations and published experimental data. Correlations of sulfide capacities, based on optical basicity using Pauling electronegativities or empirically deduced optical basicities, differ from the experimental data in both magnitude and concentration dependence. Our method provides useful predictions of sulfide capacities a priori.

  7. Optimization of the superconducting phase of hydrogen sulfide

    Energy Technology Data Exchange (ETDEWEB)

    Degtyarenko, N. N.; Masur, E. A., E-mail: eugen-mazur@mail.ru [National Research Nuclear University MEPhI (Russian Federation)

    2015-12-15

    The electron and phonon spectra, as well as the densities of electron and phonon states of the SH{sub 3} phase and the stable orthorhombic structure of hydrogen sulfide SH{sub 2}, are calculated for the pressure interval 100–225 GPa. It is found that the I4/mmm phase can be responsible for the superconducting properties of metallic hydrogen sulfide along with the SH{sub 3} phase. Sequential stages for obtaining and conservation of the SH{sub 2} phase are proposed. The properties of two (SH{sub 2} and SH{sub 3}) superconducting phases of hydrogen sulfide are compared.

  8. Optimization of the superconducting phase of hydrogen sulfide

    International Nuclear Information System (INIS)

    The electron and phonon spectra, as well as the densities of electron and phonon states of the SH3 phase and the stable orthorhombic structure of hydrogen sulfide SH2, are calculated for the pressure interval 100–225 GPa. It is found that the I4/mmm phase can be responsible for the superconducting properties of metallic hydrogen sulfide along with the SH3 phase. Sequential stages for obtaining and conservation of the SH2 phase are proposed. The properties of two (SH2 and SH3) superconducting phases of hydrogen sulfide are compared

  9. Effect of Soluble Sulfide on the Activity of Luminescent Bacteria

    OpenAIRE

    Feng Wang; Ling-Ling Wu; Hong-Wen Gao; Ying Shao

    2012-01-01

    Sulfide is an important water pollutant widely found in industrial waste water that has attracted much attention. S2−, as a weak acidic anion, is easy hydrolyzed to HS and H2S in aqueous solution. In this study, biological tests were performed to establish the toxicity of sulfide solutions on luminescent bacteria. Considering the sulfide solution was contained three substances—S2−, HS

  10. Adsorbate thermodynamics as a determinant of reaction mechanism: Pentamethylene sulfide on Mo(110)

    Energy Technology Data Exchange (ETDEWEB)

    Wiegand, B.C.; Friend, C.M.; Roberts, J.T. (Harvard Univ., Cambridge, MA (USA))

    The reactions of the totally unstrained, six-membered cyclic sulfide pentamethylene sulfide on Mo(110) have been investigated by using temperature-programmed reaction spectroscopy and X-ray photoelectron spectroscopy in an effort to identify the roles of ring size and strain in dictating reaction selectivity. Four gases products are detected in the temperature-programmed reaction of pentamethylene sulfide: dihydrogen at 380 and 590 K, pentane at 350 K, pentene at 345 K, and pentamethylene sulfide at 190 and 280 K. The kinetics for hydrocarbon production from pentamethylene sulfide are qualitatively different than for the four- and five-membered cyclic sulfides, trimethylene sulfide and tetrahydrothiophene.

  11. Micro-aeration for hydrogen sulfide removal from biogas

    Science.gov (United States)

    Duangmanee, Thanapong

    The presence of sulfur compounds (e.g. protein, sulfate, thiosulfate, sulfite, etc.) in the feed stream generates highly corrosive and odorous hydrogen sulfide during anaerobic digestion. The high sulfide level in the biogas stream is not only poisonous to many novel metal catalysts employed in thermo-catalytic processes but also reduces the quality of methane to produce renewable energy. This study used an innovative, low-maintenance, low-cost biological sulfide removal technology to remove sulfides simultaneously from both gas and liquid phase. ORP (Oxidation-Reduction-Potential) was used as the controlling parameter to precisely regulate air injection to the sulfide oxidizing unit (SOU). The microaeration technique provided just enough oxygen to partially oxidize sulfides to elemental sulfur without inhibiting methanogenesis. The SOU was equipped with a diffuser at the bottom for the dispersion of sulfide-laden biogas and injected air throughout the column. The SOU can be operated as a standalone unit or coupled with an anaerobic digester to simultaneously remove sulfide from the biogas and effluent. The integrated system was capable of reducing hydrogen sulfide in biogas from 2,450 to less than 2 ppmV with minimal sulfate production at the highest available sulfide loading rate of 0.24 kg/m3-day. More than 98% of sulfide removed was recovered as elemental sulfur. However, the standalone SOU was able to operate at high hydrogen sulfide loading of 1.46 kg/m 3-day at inlet sulfide concentration of 3000 ppmV and reduce the off-gas hydrogen sulfide concentrations to less than 10 ppmV. The experiment also revealed that the ORP controlled aeration was sensitive enough to prevent oxygen overdosing (dampening effect) during unexpected surges of aeration. Using generalized linear regression, a model predicting output H2S concentration based on input H2S concentrations, SOU medium heights, and biogas flow rates, was derived. With 95% confidence, output H2S concentration

  12. Biological and chemical sulfide oxidation in a Beggiatoa inhabited marine sediment

    DEFF Research Database (Denmark)

    Preisler, André; de Beer, Dirk; Lichtschlag, Anna;

    2007-01-01

    The ecological niche of nitrate-storing Beggiatoa, and their contribution to the removal of sulfide were investigated in coastal sediment. With microsensors a clear suboxic zone of 2-10 cm thick was identified, where neither oxygen nor free sulfide was detectable. In this zone most of the Beggiat...... were found, where they oxidize sulfide with internally stored nitrate. The sulfide input into the suboxic zone was dominated by an upward sulfide flux from deeper sediment, whereas the local production in the suboxic zone was much smaller. Despite their abundance, the calculated sulfide......, where they oxidize sulfide with internally stored nitrate. The sulfide input into the suboxic zone was dominated by an upward sulfide flux from deeper sediment, whereas the local production in the suboxic zone was much smaller. Despite their abundance, the calculated sulfide-oxidizing capacity...

  13. Sulfide mineralization in ultramafic rocks of the Faryab ophiolite complex, southern Kerman

    OpenAIRE

    Mohammad Ali Rajabzadeh; Fatemeh Al Sadi

    2015-01-01

    Introduction Worldwide, Ni-Cu and PGE magmatic sulfide deposits are confined to the lower parts of stratiform mafic and ultramafic complexes. However, ophiolite mafic and ultramafic complexes have been rarely explored for sulfide deposits despite the fact that they have been extensively explored and exploited for chromite. Sulfide saturation during magmatic evolution is necessary for sulfide mineralization, in which sulfide melts scavenge chalcophile metals from the parent magma and conc...

  14. [Activity of hydrogen sulfide production enzymes in kidneys of rats].

    Science.gov (United States)

    Mel'nyk, A V; Pentiuk, O O

    2009-01-01

    An experimental research of activity and kinetic descriptions of enzymes participating in formation of hydrogen sulfide in the kidney of rats has been carried out. It was established that cystein, homocystein and thiosulphate are the basic substrates for hydrogen sulfide synthesis. The higest activity for hydrogen sulfide production belongs to thiosulfate-dithiolsulfurtransferase and cysteine aminotransferase, less activity is characteristic of cystathionine beta-synthase and cystathio-nine gamma-lyase. The highest affinity to substrate is registered for thiosulfate-dithiolsulfurtransferase and cystathionine gamma-lyase. It is discovered that the substrate inhibition is typical of all hydrogen sulfide formation enzymes, although this characteristic is the most expressed thiosulfat-dithiolsulfurtransferase. PMID:20387629

  15. Optimization of biological sulfide removal in a CSTR bioreactor.

    Science.gov (United States)

    Roosta, Aliakbar; Jahanmiri, Abdolhossein; Mowla, Dariush; Niazi, Ali; Sotoodeh, Hamidreza

    2012-08-01

    In this study, biological sulfide removal from natural gas in a continuous bioreactor is investigated for estimation of the optimal operational parameters. According to the carried out reactions, sulfide can be converted to elemental sulfur, sulfate, thiosulfate, and polysulfide, of which elemental sulfur is the desired product. A mathematical model is developed and was used for investigation of the effect of various parameters on elemental sulfur selectivity. The results of the simulation show that elemental sulfur selectivity is a function of dissolved oxygen, sulfide load, pH, and concentration of bacteria. Optimal parameter values are calculated for maximum elemental sulfur selectivity by using genetic algorithm as an adaptive heuristic search. In the optimal conditions, 87.76% of sulfide loaded to the bioreactor is converted to elemental sulfur.

  16. Hydrogen Sulfide Micro-Sensor for Biomass Fouling Detection Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Hydrogen Sulfide (H2S)is the leading chemical agent causing human fatalities following inhalation exposures. The overall aim of this project is to develop and...

  17. The hydrogen sulfide metabolite trimethylsulfonium is found in human urine

    Science.gov (United States)

    Lajin, Bassam; Francesconi, Kevin A.

    2016-06-01

    Hydrogen sulfide is the third and most recently discovered gaseous signaling molecule following nitric oxide and carbon monoxide, playing important roles both in normal physiological conditions and disease progression. The trimethylsulfonium ion (TMS) can result from successive methylation reactions of hydrogen sulfide. No report exists so far about the presence or quantities of TMS in human urine. We developed a method for determining TMS in urine using liquid chromatography-electrospray ionization-triple quadrupole mass spectrometry (LC-ESI-QQQ), and applied the method to establish the urinary levels of TMS in a group of human volunteers. The measured urinary levels of TMS were in the nanomolar range, which is commensurate with the steady-state tissue concentrations of hydrogen sulfide previously reported in the literature. The developed method can be used in future studies for the quantification of urinary TMS as a potential biomarker for hydrogen sulfide body pools.

  18. Selective adsorption of bacteria on sulfide minerals surface

    Institute of Scientific and Technical Information of China (English)

    JIA Chun-yun; WEI De-zhou; LIU Wen-gang; HAN Cong; GAO Shu-ling; WANG Yu-juan

    2008-01-01

    The adsorption of bacteria on sulfide minerals surface was studied, and the selective adsorption mechanism of cells on the sulfide minerals was investigated by means of FTIR, UVS and XPS. The results show that the three strains of bacteria adsorbed more preferentially on pyrite than on other two sulfide minerals surface at neutral and alkaline pH conditions. FTIR and UVS of three strains of bacteria indicate that there are more functional groups on their surface, such as O-H, C=O, N-H, C-O, and the content of saccharide is more than that of protein. The state of every element on sulfide minerals surface was analyzed by XPS. The empty orbital number of electronic shell of metal ions on minerals surface is important in selective adsorption process, and some stable constants of metal coordinates can be used to explain the contribution of some groups in saccharide of cell wall to the selective adsorption.

  19. Conspicuous veils formed by vibrioid bacteria on sulfidic marine sediment

    DEFF Research Database (Denmark)

    Thar, Roland Matthias; Kühl, Michael

    2002-01-01

    , but the bacteria have so far not been isolated in pure culture, and a detailed characterization of their metabolism is still lacking. The bacteria are colorless, gram-negative, and vibrioid-shaped (1.3- to 2.5- by 4- to 10-µm) cells that multiply by binary division and contain several spherical inclusions of poly......We describe the morphology and behavior of a hitherto unknown bacterial species that forms conspicuous veils (typical dimensions, 30 by 30 mm) on sulfidic marine sediment. The new bacteria were enriched on complex sulfidic medium within a benthic gradient chamber in oxygen-sulfide countergradients......-ß-hydroxybutyric acid. The cells have bipolar polytrichous flagella and exhibit a unique swimming pattern, rotating and translating along their short axis. Free-swimming cells showed aerotaxis and aggregated at ca. 2 µM oxygen within opposing oxygen-sulfide gradients, where they were able to attach via a mucous stalk...

  20. The hydrogen sulfide metabolite trimethylsulfonium is found in human urine

    OpenAIRE

    Bassam Lajin; Francesconi, Kevin A

    2016-01-01

    Hydrogen sulfide is the third and most recently discovered gaseous signaling molecule following nitric oxide and carbon monoxide, playing important roles both in normal physiological conditions and disease progression. The trimethylsulfonium ion (TMS) can result from successive methylation reactions of hydrogen sulfide. No report exists so far about the presence or quantities of TMS in human urine. We developed a method for determining TMS in urine using liquid chromatography-electrospray ion...

  1. An eco-friendly oxidation of sulfide compounds

    Indian Academy of Sciences (India)

    RAVINDRA B WAGH; SITARAM H GUND; JAYASHREE M NAGARKAR

    2016-08-01

    An improved green route has been developed for the oxidation of sulfide compounds. Albendazole is converted to ricobendazole or albendazole sulfone using H₂O₂ as an oxidant and H₂O as the solvent. High yields of the corresponding products were obtained by carrying out the reaction at room temperature. This synthetic method is environmentally clean and safe, operationally simple for the oxidation of other benzimidazole anthelmintics and various sulfide compounds.

  2. INVESTIGATIONS ON BIOCHEMICAL PURIFICATION OF GROUND WATER FROM HYDROGEN SULFIDE

    Directory of Open Access Journals (Sweden)

    Yu. P. Sedlukho

    2015-01-01

    Full Text Available The paper considers problems and features of biochemical removal of hydrogen sulfide from ground water. The analysis of existing methods for purification of ground water from hydrogen sulfide has been given in the paper. The paper has established shortcomings of physical and chemical purification of ground water. While using aeration methods for removal of hydrogen sulfide formation of colloidal sulfur that gives muddiness and opalescence to water occurs due to partial chemical air oxidation. In addition to this violation of sulfide-carbonate equilibrium taking place in the process of aeration due to desorption of H2S and CO2, often leads to clogging of degasifier nozzles with formed CaCO3 that causes serious operational problems. Chemical methods require relatively large flow of complex reagent facilities, storage facilities and transportation costs.In terms of hydrogen sulfide ground water purification the greatest interest is given to the biochemical method. Factors deterring widespread application of the biochemical method is its insufficient previous investigation and necessity to execute special research in order to determine optimal process parameters while purifying groundwater of a particular water supply source. Biochemical methods for oxidation of sulfur compounds are based on natural biological processes that ensure natural sulfur cycle. S. Vinogradsky has established a two-stage mechanism for oxidation of hydrogen sulfide with sulfur bacteria (Beggiatoa. The first stage presupposes oxidation of hydrogen sulphide to elemental sulfur which is accumulating in the cytoplasm in the form of globules. During the second stage sulfur bacteria begin to oxidize intracellular sulfur to sulfuric acid due to shortage of hydrogen sulfide.The paper provides the results of technological tests of large-scale pilot plants for biochemical purification of groundwater from hydrogen sulfide in semi-industrial conditions. Dependences of water quality

  3. Mechanism for SOFC anode degradation from hydrogen sulfide exposure

    Energy Technology Data Exchange (ETDEWEB)

    Lussier, A.; Dvorak, J.; Idzerda, Y.U. [Department of Physics, Montana State University, EPS Building, Room 264, Bozeman, MT 59717 (United States); Sofie, S. [Department of Mechanical and Industrial Engineering, Montana State University, 201E Roberts Hall, Bozeman, MT 59717 (United States)

    2008-07-15

    Recent results on solid oxide fuel cells with Ni/YSZ and Ni/GDC anodes reveal a mechanism for permanent performance degradation due to hydrogen sulfide exposure. Our results confirm the temporary performance decline observed by others but also reveal a mechanism for the long term permanent degradation. We find that hydrogen sulfide leads to nickel migration and depletion in the anode, thereby compromising electrical conductivity and cell performance. (author)

  4. Sulfide oxidation in fluidized bed bioreactor using nylon support material

    Institute of Scientific and Technical Information of China (English)

    Varsha Midha; M K Jha; Apurba Dey

    2012-01-01

    A continuous fluidized bed bioreactor(FBBR)with nylon support particles was used to treat synthetic sulfide wastewater at different hydraulic retention time of 25,50 and 75 min and upflow velocity of 14,17 and 20 m/hr.The effects of upflow velocity,hydraulic retention time and reactor operation time on sulfide oxidation rate were studied using statistical model.Mixed culture obtained from the activated sludge,taken from tannery effluent treatment plant,was used as a source for microorganisms.The diameter and density of the nylon particles were 2-3 mm and 1140 kg/m3,respectively.Experiments were carried out in the reactor at a temperature of(30± 2)℃,at a fixed bed height of 16 cm after the formation of biofilm on the surface of support particles.Biofilm thickness reached(42±3)μm after 15 days from reactor start-up.The sulfide oxidation,sulfate and sulfur formation is examined at all hydraulic retention times and upflow velocities.The results indicated that almost 90%-92% sulfide oxidation was achieved at all hydraulic retention times.Statistical model could explain 94% of the variability and analysis of variance showed that upflow velocity and hydraulic retention time slightly affected the sulfide oxidation rate.The highest sulfide oxidation of 92% with 70% sulfur was obtained at hydraulic retention time of 75 min and upflow velocity of 14 m/hr.

  5. Sulfide capacity of high alumina blast furnace slags

    Science.gov (United States)

    Shankar, Amitabh; Görnerup, Märten; Seetharaman, S.; Lahiri, A. K.

    2006-12-01

    Sulfide capacities of high alumina blast furnace slags were experimentally determined using the gas-slag equilibration technique. Two different slag systems were considered for the current study, namely, CaO-SiO2-MgO-Al2O3 quaternary and CaO-SiO2-MgO-Al2O3-TiO2 quinary system. The liquid slag was equilibrated with the Ar-CO-CO2-SO2 gas mixture. Experiments were conducted in the temperature range of 1773 to 1873 K. The effects of temperature, basicity, and the MgO and TiO2 contents of slags on sulfide capacity were studied. As expected, sulfide capacity was found to increase with the increase in temperature and basicity. At the higher experimental temperature, titania decreases the sulfide capacity of slag. However, at the lower temperature, there was no significant effect of titania on the sulfide capacity of slag. Sulfide capacity increases with the increase in MgO content of slag if the MgO content is more than 5 pct.

  6. Dihydrogen Activation by Titanium Sulfide Complexes

    Science.gov (United States)

    Sweeney, Zachary K.; Polse, Jennifer L.; Bergman*, Robert G.; Andersen*, Richard A.

    2005-01-01

    The titanocene sulfido complex Cp*2Ti(S)py (1, Cp* = pentamethylcyclopentadienyl; py = pyridine) is synthesized by addition of a suspension of S8 to a toluene solution of Cp*2Ti-(CH2CH2) (2) and py. The rate of rotation of the pyridine ligand in solution was determined by 1H NMR spectroscopy, and the structure of 1 was determined by X-ray crystallography. Complex 1 reacts reversibly with dihydrogen to give Cp*2Ti(H)SH (6) and py. Reaction of 1 with HD gives an equilibrium mixture of Cp*2Ti(D)SH and Cp*2Ti(H)SD; H2 and D2 are not formed in this reaction. 1D 1H NMR magnetization transfer spectra and 2D EXSY 1H NMR spectra of 6 in the presence of H2 show that in solution the H2, hydride, and hydrosulfido hydrogen atoms exchange. A four-center mechanism for this exchange is proposed. The EXSY studies show that the Ti–H and S–H hydrogens exchange with each other more rapidly than either of those hydrogens exchanges with external H2. A transient dihydrogen complex intermediate is proposed to explain this observation. The infrared spectrum of 6 shows an absorption assigned to the Ti–H stretching mode at 1591 cm−1 that shifts upon deuteration to 1154 cm−1. Reaction of 1 with trimethylsilane, diethylsilane, or dimethylsilane gives Cp*2-Ti(H)SSiMe3 (7), Cp*2Ti(H)SSiHEt2 (8), or Cp*2Ti(H)SSiHMe2 (9), respectively. The isotope effect for the reaction producing 7 has been measured, and a mechanism is proposed. Treatment of 1 with an additional equivalent of S8 results in the formation of the disulfide Cp*2Ti(S2) (4). Acetylene inserts into the Ti–S bond of 4 to produce the vinyl disulfide complex 5. The structures of 4 and 5 have been determined by X-ray diffraction. Compound 4 reacts with 2 in the presence of py to produce 1. Phosphines react with 4 in the presence of H2 to provide 6 and the corresponding phosphine sulfide. Reaction of hydrogen with 4 gives Cp*2-Ti(SH)2 (3). The reactions of 1 and 4 with dihydrogen provide a model for possible mechanisms of H2

  7. Hydrogen Sulfide and Endothelium-Dependent Vasorelaxation

    Directory of Open Access Journals (Sweden)

    Jerzy Bełtowski

    2014-12-01

    Full Text Available In addition to nitric oxide and carbon monoxide, hydrogen sulfide (H2S, synthesized enzymatically from l-cysteine or l-homocysteine, is the third gasotransmitter in mammals. Endogenous H2S is involved in the regulation of many physiological processes, including vascular tone. Although initially it was suggested that in the vascular wall H2S is synthesized only by smooth muscle cells and relaxes them by activating ATP-sensitive potassium channels, more recent studies indicate that H2S is synthesized in endothelial cells as well. Endothelial H2S production is stimulated by many factors, including acetylcholine, shear stress, adipose tissue hormone leptin, estrogens and plant flavonoids. In some vascular preparations H2S plays a role of endothelium-derived hyperpolarizing factor by activating small and intermediate-conductance calcium-activated potassium channels. Endothelial H2S signaling is up-regulated in some pathologies, such as obesity and cerebral ischemia-reperfusion. In addition, H2S activates endothelial NO synthase and inhibits cGMP degradation by phosphodiesterase 5 thus potentiating the effect of NO-cGMP pathway. Moreover, H2S-derived polysulfides directly activate protein kinase G. Finally, H2S interacts with NO to form nitroxyl (HNO—a potent vasorelaxant. H2S appears to play an important and multidimensional role in endothelium-dependent vasorelaxation.

  8. Anisotropic Optical Properties of Layered Germanium Sulfide

    CERN Document Server

    Tan, Dezhi; Wang, Feijiu; Mohamed, Nur Baizura; Mouri, Shinichiro; Sandhaya, Koirala; Zhang, Wenjing; Miyauchi, Yuhei; Ohfuchi, Mari; Matsuda, Kazunari

    2016-01-01

    Two-dimensional (2D) layered materials, transition metal dichalcogenides and black phosphorus, have attracted much interest from the viewpoints of fundamental physics and device applications. The establishment of new functionalities in anisotropic layered 2D materials is a challenging but rewarding frontier, owing to their remarkable optical properties and prospects for new devices. Here, we report the anisotropic optical properties of layered 2D monochalcogenide of germanium sulfide (GeS). Three Raman scattering peaks corresponding to the B3g, A1g, and A2g modes with strong polarization dependence are demonstrated in the GeS flakes, which validates polarized Raman spectroscopy as an effective method for identifying the crystal orientation of anisotropic layered GeS. Photoluminescence (PL) is observed with a peak at around 1.66 eV that originates from the direct optical transition in GeS at room temperature. Moreover, determination of the polarization dependent characteristics of the PL and absorption reveals...

  9. Hydrogen Sulfide and Cellular Redox Homeostasis

    Directory of Open Access Journals (Sweden)

    Zhi-Zhong Xie

    2016-01-01

    Full Text Available Intracellular redox imbalance is mainly caused by overproduction of reactive oxygen species (ROS or weakness of the natural antioxidant defense system. It is involved in the pathophysiology of a wide array of human diseases. Hydrogen sulfide (H2S is now recognized as the third “gasotransmitters” and proved to exert a wide range of physiological and cytoprotective functions in the biological systems. Among these functions, the role of H2S in oxidative stress has been one of the main focuses over years. However, the underlying mechanisms for the antioxidant effect of H2S are still poorly comprehended. This review presents an overview of the current understanding of H2S specially focusing on the new understanding and mechanisms of the antioxidant effects of H2S based on recent reports. Both inhibition of ROS generation and stimulation of antioxidants are discussed. H2S-induced S-sulfhydration of key proteins (e.g., p66Shc and Keap1 is also one of the focuses of this review.

  10. Hydrogen Sulfide and Cellular Redox Homeostasis

    Science.gov (United States)

    Xie, Zhi-Zhong; Liu, Yang; Bian, Jin-Song

    2016-01-01

    Intracellular redox imbalance is mainly caused by overproduction of reactive oxygen species (ROS) or weakness of the natural antioxidant defense system. It is involved in the pathophysiology of a wide array of human diseases. Hydrogen sulfide (H2S) is now recognized as the third “gasotransmitters” and proved to exert a wide range of physiological and cytoprotective functions in the biological systems. Among these functions, the role of H2S in oxidative stress has been one of the main focuses over years. However, the underlying mechanisms for the antioxidant effect of H2S are still poorly comprehended. This review presents an overview of the current understanding of H2S specially focusing on the new understanding and mechanisms of the antioxidant effects of H2S based on recent reports. Both inhibition of ROS generation and stimulation of antioxidants are discussed. H2S-induced S-sulfhydration of key proteins (e.g., p66Shc and Keap1) is also one of the focuses of this review. PMID:26881033

  11. Design of a homogeneous subcritical nuclear reactor based on thorium with a source of californium 252; Diseno de un reactor nuclear subcritico homogeneo a base de Torio con una fuente de Californio 252

    Energy Technology Data Exchange (ETDEWEB)

    Delgado H, C. E.; Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas, Zac. (Mexico); Sajo B, L., E-mail: ce_delgado89@hotmail.com [Universidad Simon Bolivar, Laboratorio de Fisica Nuclear, Apdo. 89000, 1080A Caracas (Venezuela, Bolivarian Republic of)

    2015-10-15

    Full text: One of the energy alternatives to fossil fuels which do not produce greenhouse gases is the nuclear energy. One of the drawbacks of this alternative is the generation of radioactive wastes of long half-life and its relation to the generation of nuclear materials to produce weapons of mass destruction. An option to these drawbacks of nuclear energy is to use Thorium as part of the nuclear fuel which it becomes in U{sup 233} when capturing neutrons, that is a fissile material. In this paper Monte Carlo methods were used to design a homogeneous subcritical reactor based on thorium. As neutron reflector graphite was used. The reactor core is homogeneous and is formed of 70% light water as moderator, 12% of enriched uranium UO{sub 2}(NO{sub 3}){sub 4} and 18% of thorium Th(NO{sub 3}){sub 4} as fuel. To start the nuclear fission chain reaction an isotopic source of californium 252 was used with an intensity of 4.6 x 10{sup 7} s{sup -1}. In the design the value of the effective multiplication factor, whose value turned out k{sub eff} <1 was calculated. Also, the neutron spectra at different distances from the source and the total fluence were calculated, as well as the values of the ambient dose equivalent in the periphery of the reactor. (Author)

  12. 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.

  13. Dimethyl sulfide in the Amazon rain forest

    Science.gov (United States)

    Jardine, K.; Yañez-Serrano, A. M.; Williams, J.; Kunert, N.; Jardine, A.; Taylor, T.; Abrell, L.; Artaxo, P.; Guenther, A.; Hewitt, C. N.; House, E.; Florentino, A. P.; Manzi, A.; Higuchi, N.; Kesselmeier, J.; Behrendt, T.; Veres, P. R.; Derstroff, B.; Fuentes, J. D.; Martin, S. T.; Andreae, M. O.

    2015-01-01

    Surface-to-atmosphere emissions of dimethyl sulfide (DMS) may impact global climate through the formation of gaseous sulfuric acid, which can yield secondary sulfate aerosols and contribute to new particle formation. While oceans are generally considered the dominant sources of DMS, a shortage of ecosystem observations prevents an accurate analysis of terrestrial DMS sources. Using mass spectrometry, we quantified ambient DMS mixing ratios within and above a primary rainforest ecosystem in the central Amazon Basin in real-time (2010-2011) and at high vertical resolution (2013-2014). Elevated but highly variable DMS mixing ratios were observed within the canopy, showing clear evidence of a net ecosystem source to the atmosphere during both day and night in both the dry and wet seasons. Periods of high DMS mixing ratios lasting up to 8 h (up to 160 parts per trillion (ppt)) often occurred within the canopy and near the surface during many evenings and nights. Daytime gradients showed mixing ratios (up to 80 ppt) peaking near the top of the canopy as well as near the ground following a rain event. The spatial and temporal distribution of DMS suggests that ambient levels and their potential climatic impacts are dominated by local soil and plant emissions. A soil source was confirmed by measurements of DMS emission fluxes from Amazon soils as a function of temperature and soil moisture. Furthermore, light- and temperature-dependent DMS emissions were measured from seven tropical tree species. Our study has important implications for understanding terrestrial DMS sources and their role in coupled land-atmosphere climate feedbacks.

  14. Hydrogen sulfide and nervous system regulation

    Institute of Scientific and Technical Information of China (English)

    ZHOU Cheng-fang; TANG Xiao-qing

    2011-01-01

    Objective This review discusses the current status and progress in studies on the roles of hydrogen sulfide (H2S) in regulation of neurotoxicity,neuroprotection,and neuromodulator,as well as its therapeutic potential for neurodegenerative disorders.Data sources The data used in this review were mainly from Medline and PubMed published in English from 2001 to August 2011.The search terms were “hydrogen sulfide”,“neuron”,and “neurodegenerative disorders”.Study selection Articles regarding the regulation of neuronal function,the protection against neuronal damage and neurological diseases,and their possible cellular and molecular mechanisms associated with H2S were selected.Results The inhibited generation of endogenous H2S is implicated in 1-methy-4-phenylpyridinium ion,6-OHDA,and homocysteine-triggered neurotoxicity.H2S elicits neuroprotection in Alzheimer's disease and Parkinson's disease models as well as protecting neurons against oxidative stress,ischemia,and hypoxia-induced neuronal death.H2S offers anti-oxidant,anti-inflammatory and anti-apoptotic effects,as well as activates ATP-sensitive potassium channels and cystic fibrosis transmembrane conductance regulator Cl- channels.H2S regulates the long-term potentiation (LTP) and GABAB receptors in the hippocampus,as well as intracellular calcium and pH homeostasis in neurons and glia cells.Conclusions These articles suggest that endogenous H2S may regulate the toxicity of neurotoxin.H2S not only acts as a neuroprotectant but also serves as a novel neuromodulator.

  15. Electrical properties of seafloor massive sulfides

    Science.gov (United States)

    Spagnoli, Giovanni; Hannington, Mark; Bairlein, Katharina; Hördt, Andreas; Jegen, Marion; Petersen, Sven; Laurila, Tea

    2016-06-01

    Seafloor massive sulfide (SMS) deposits are increasingly seen as important marine metal resources for the future. A growing number of industrialized nations are involved in the surveying and sampling of such deposits by drilling. Drill ships are expensive and their availability can be limited; seabed drill rigs are a cost-effective alternative and more suitable for obtaining cores for resource evaluation. In order to achieve the objectives of resource evaluations, details are required of the geological, mineralogical, and physical properties of the polymetallic deposits and their host rocks. Electrical properties of the deposits and their ore minerals are distinct from their unmineralized host rocks. Therefore, the use of electrical methods to detect SMS while drilling and recovering drill cores could decrease the costs and accelerate offshore operations by limiting the amount of drilling in unmineralized material. This paper presents new data regarding the electrical properties of SMS cores that can be used in that assessment. Frequency-dependent complex electrical resistivity in the frequency range between 0.002 and 100 Hz was examined in order to potentially discriminate between different types of fresh rocks, alteration and mineralization. Forty mini-cores of SMS and unmineralized host rocks were tested in the laboratory, originating from different tectonic settings such as the intermediate-spreading ridges of the Galapagos and Axial Seamount, and the Pacmanus back-arc basin. The results indicate that there is a clear potential to distinguish between mineralized and non-mineralized samples, with some evidence that even different types of mineralization can be discriminated. This could be achieved using resistivity magnitude alone with appropriate rig-mounted electrical sensors. Exploiting the frequency-dependent behavior of resistivity might amplify the differences and further improve the rock characterization.

  16. Microbial control of hydrogen sulfide production in a porous medium

    Energy Technology Data Exchange (ETDEWEB)

    McInerney, M.J.; Wofford, N.Q. [Univ. of Oklahoma, Norman, OK (United States); Sublette, K.L. [Univ. of Tulsa, OK (United States)

    1996-12-31

    The ability of a sulfide- and glutaraldehyde-tolerant strain of Thiobacillus denitrificans (strain F) to control sulfide production in an experimental system of cores and formation water from the Redfield, Iowa natural gas storage facility was investigated. A stable, sulfide-producing biofilm was established in two separate core systems, one of which was inoculated with strain F, and the other core system (control) was treated in an identical manner, but was not inoculated with strain F. When formation water with 10 mM acetate and 5mM nitrate was injected into both core systems, the effluent sulfide concentrations in the control core system ranged from 200-460 {mu}M. In the test core system inoculated with strain F, the effluent sulfide concentrations were lower, ranging from 70-110 {mu}M. In order to determine whether strain F could control sulfide production under optimal conditions for sulfate-reducing bacteria, the electron donor was changed to lactate, and inorganic nutrients (nitrogen and phosphate sources) were added to the formation water. When nutrient-supplemented formation water with 3.1 mM lactate and 10 mM nitrate was used, the effluent sulfide concentrations of the control core system initially increased to about 3800 pM, and then decreased to about 1100 {mu}M after 5 wk. However, in the test core system inoculated with strain F, the effluent sulfide concentrations were much lower, 160-330 {mu}M. Nitrate consumption (5 mM) and high concentrations (101-1011 cells/mL) of strain F were detected in the test core system. An accumulation of biomass occurred in the influent lines during 2 mo of continuous operation, but only a small increase in injection pressure was observed. These studies showed that inoculation with strain F was needed for effective control of sulfide production, and that significant plugging or loss of injectivity owing to microbial inoculation did not occur. 7 refs., 3 figs., 1 tab.

  17. Sulfide Oxidation in the Anoxic Black-Sea Chemocline

    DEFF Research Database (Denmark)

    JØRGENSEN, BB; FOSSING, H.; WIRSEN, CO;

    1991-01-01

    that the measured H2S oxidation rates were 4-fold higher than could be explained by the downward flux of organic carbon and too high to balance the availability of electron acceptors such as oxidized iron or manganese. A nitrate maximum at the lower boundary of the O2 zone did not extend down to the sulfide zone.......The depth distributions of O2 and H2S and of the activity of chemical or bacterial sulfide oxidation were studied in the chemocline of the central Black Sea. Relative to measurements from earlier studies, the sulfide zone had moved upwards by 20-50 m and was now (May 1988) situated at a depth of 81......-99 m. Oxygen in the water column immediately overlying the sulfide zone was depleted to undetectable levels resulting in a 20-30-m deep intermediate layer of O2- and H2S-free water. Radiotracer studies with S-35-labelled H2S showed that high rates of sulfide oxidation, up to a few micromoles per liter...

  18. Species-specific enzymatic tolerance of sulfide toxicity in plant roots.

    Science.gov (United States)

    Martin, Nicole M; Maricle, Brian R

    2015-03-01

    Toxic effects of sulfide come from a poisoning of a number of enzymes, especially cytochrome c oxidase, which catalyzes the terminal step in mitochondrial aerobic respiration. Despite this, some estuarine plants live in sulfide-rich sediments. We hypothesized estuarine and flooding-tolerant species might be more tolerant of sulfide compared to upland species, and this was tested by measures of root cytochrome c oxidase and alcohol dehydrogenase activities in extracts exposed to sulfide. Enzyme activities were measured in 0, 5, 10, 15, and 20 μM sodium sulfide, and compared among 17 species of plants. Activities of alcohol dehydrogenase and cytochrome c oxidase were both reduced by increasing sulfide concentration, but cytochrome c oxidase was more sensitive to sulfide compared to alcohol dehydrogenase. Activities of cytochrome c oxidase were reduced to near zero at 5-10 μM sulfide whereas alcohol dehydrogenase activities were only reduced by about 50% at 10 μM sulfide. All species were sensitive to increasing sulfide, but to different degrees. Cytochrome c oxidase in flooding-sensitive species was decreased to near zero activity at 5 μM sulfide, whereas activities in some flooding-tolerant species were still detectable until 15 μM sulfide. Cytochrome c oxidase activities in some estuarine species were low even in the absence of sulfide, perhaps an adaptation to avoid sulfide vulnerability in their native, sulfide-rich habitat. This illustrates the potent metabolic effects of sulfide, and this is the first demonstration of varying sensitivities of cytochrome c oxidase to sulfide across organisms, making these data of novel importance.

  19. Simultaneous removal of sulfide, nitrate and acetate under denitrifying sulfide removal condition: Modeling and experimental validation

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Xijun; Chen, Chuan; Wang, Aijie; Guo, Wanqian; Zhou, Xu [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); Lee, Duu-Jong, E-mail: djlee@ntu.edu.tw [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); Department of Chemical Engineering, National Taiwan University, Taipei 106, Taiwan (China); Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan (China); Ren, Nanqi, E-mail: rnq@hit.edu.cn [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); Chang, Jo-Shu [Research Center for Energy Technology and Strategy, National Cheng Kung University, Tainan, Taiwan (China)

    2014-01-15

    Graphical abstract: Model evaluation applied to case study 1: (A-G) S{sup 2−}, NO{sub 3}{sup −}-N, NO{sub 2}{sup −}-N, and Ac{sup −}-C profiles under initial sulfide concentrations of 156.2 (A), 539 (B), 964 (C), 1490 (D), 342.7 (E), 718 (F), and 1140.7 (G) mg L{sup −1}. The solid line represents simulated result and scatter represents experimental result. -- Highlights: • This work developed a mathematical model for DSR process. • Kinetics of sulfur–nitrogen–carbon and interactions between denitrifiers were studied. • Kinetic parameters of the model were estimated via data fitting. • The model described kinetic behaviors of DSR processes over wide parametric range. -- Abstract: Simultaneous removal of sulfide (S{sup 2−}), nitrate (NO{sub 3}{sup −}) and acetate (Ac{sup −}) under denitrifying sulfide removal process (DSR) is a novel biological wastewater treatment process. This work developed a mathematical model to describe the kinetic behavior of sulfur–nitrogen–carbon and interactions between autotrophic denitrifiers and heterotrophic denitrifiers. The kinetic parameters of the model were estimated via data fitting considering the effects of initial S{sup 2−} concentration, S{sup 2−}/NO{sub 3}{sup −}-N ratio and Ac{sup −}-C/NO{sub 3}{sup −}-N ratio. Simulation supported that the heterotrophic denitratation step (NO{sub 3}{sup −} reduction to NO{sub 2}{sup −}) was inhibited by S{sup 2−} compared with the denitritation step (NO{sub 2}{sup −} reduction to N{sub 2}). Also, the S{sup 2−} oxidation by autotrophic denitrifiers was shown two times lower in rate with NO{sub 2}{sup −} as electron acceptor than that with NO{sub 3}{sup −} as electron acceptor. NO{sub 3}{sup −} reduction by autotrophic denitrifiers occurs 3–10 times slower when S{sup 0} participates as final electron donor compared to the S{sup 2−}-driven pathway. Model simulation on continuous-flow DSR reactor suggested that the adjustment of

  20. Diverse sulfur metabolisms from two subterranean sulfidic spring systems.

    Science.gov (United States)

    Rossmassler, Karen; Hanson, Thomas E; Campbell, Barbara J

    2016-08-01

    In sulfidic environments, microbes oxidize reduced sulfur compounds via several pathways. We used metagenomics to investigate sulfur metabolic pathways from microbial mat communities in two subterranean sulfidic streams in Lower Kane Cave, WY, USA and from Glenwood Hot Springs, CO, USA. Both unassembled and targeted recA gene assembly analyses revealed that these streams were dominated by Epsilonproteobacteria and Gammaproteobacteria, including groups related to Sulfurovum, Sulfurospirillum, Thiothrix and an epsilonproteobacterial group with no close cultured relatives. Genes encoding sulfide:quinone oxidoreductase (SQR) were abundant at all sites, but the specific SQR type and the taxonomic affiliation of each type differed between sites. The abundance of thiosulfate oxidation pathway genes (Sox) was not consistent between sites, although overall they were less abundant than SQR genes. Furthermore, the Sox pathway appeared to be incomplete in all samples. This work reveals both variations in sulfur metabolism within and between taxonomic groups found in these systems, and the presence of novel epsilonproteobacterial groups. PMID:27324397

  1. Sulfide Catalysts Supported on Porous Aromatic Frameworks for Naphthalene Hydroprocessing

    Directory of Open Access Journals (Sweden)

    Eduard Karakhanov

    2016-08-01

    Full Text Available This paper describes the first example of using porous aromatic frameworks as supports for sulfide catalysts for the hydrogenation of aromatic hydrocarbons. The synthesis of bimetallic Ni-W and Ni-Mo sulfides was performed by in situ decomposition of [(n-Bu4N]2[Ni(MeS42] (Me = W, Mo complexes, supported on mesoporous aromatic framework with a diamond-like structure. It is shown that the highest naphthalene conversions were achieved in the case of additional sulfidation with sulfur. After the reaction, catalysts were characterized by X-ray photoelectron spectroscopy and high-resolution transmission electron microscopy. The activity of synthesized catalysts has been studied using naphthalene as a model substrate. The materials used in this study were substantially active in hydrogenation and slightly in hydrocracking of naphthalene.

  2. Extraction of Nanosized Cobalt Sulfide from Spent Hydrocracking Catalyst

    Directory of Open Access Journals (Sweden)

    Samia A. Kosa

    2013-01-01

    Full Text Available The processes used for the extraction of metals (Co, Mo, and Al from spent hydrotreating catalysts were investigated in this study. A detailed mechanism of the metal extraction process is described. Additionally, a simulation study was performed to understand the sulfidizing mechanism. The suggested separation procedure was effective and achieved an extraction of approximately 80–90%. In addition, the sulfidization mechanism was identified. This sulfidizing process for Co was found to involve an intermediate, the structure of which was proposed. This proposed intermediate was confirmed through simulations. Moreover, the activities of the spent and the regenerated catalyst were examined in the cracking of toluene. The modification of the spent catalyst through the use of different iron oxide loadings improved the catalytic activity.

  3. Mechanism of sulfide effect on viscosity of HPAM polymer solution

    Institute of Scientific and Technical Information of China (English)

    康万利; 周阳; 王志伟; 孟令伟; 刘述忍; 白宝君

    2008-01-01

    The effect of sulfide on HPAM solution viscosity was studied using BROOKFIELD DV-II viscometer,and the interaction mechanism was discussed.The HPAM solution viscosity was investigated through fully reducing sulfide by the addition of hydrogen peroxide oxidation,and the mechanism of increasing polymer viscosity was investigated.The experimental results also show that there is a critical concentration of 15 mg/L.Below it,the loss rate of HPAM solution viscosity increases more rapidly,but becomes slowly above the critical concentration.A theoretical guidance for oilfields to prepare polymer solution using sewage-water by eliminating sulfide,and it is also importance to prepare polymer solution using sewage-water and save fresh water.

  4. Investigation of chemical suppressants for inactivation of sulfide ores

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In order to investigate the effective control method of spontaneous combustion in the mining of sulfide ore deposits, This paper presents the testing results of several selected chemicals (water glass, calcium chloride, calcium oxide, magnesium oxide and their composites) as oxidation suppressants for sulfide ores. A weight increment scaling method was used to measure suppressant performance, and this method proved to be accurate, simple and convenient. Based on a large number of experiments, the test results show that four types of chemical mixtures demonstrate a good performance in reducing the oxidation rate of seven active sulfide ore samples by up to 27% to 100% during an initial 76 d period. The mixtures of water glass mixed with calcium chloride and magnesium oxide mixed with calcium chloride can also act as fire suppressants when used with fire sprinkling systems.

  5. Laser cleaning of sulfide scale on compressor impeller blade

    Science.gov (United States)

    Tang, Q. H.; Zhou, D.; Wang, Y. L.; Liu, G. F.

    2015-11-01

    Sulfide scale on the surface of a compressor impeller blade can considerably reduce the impeller performance and its service life. To prepare for subsequent remanufacturing, such as plasma spraying, it needs to be removed completely. In the corrosion process on an FV(520)B stainless steel, sulfide scale is divided into two layers because of different outward diffusion rates of Cr, Ni and Fe. In this paper, the cleaning threshold values of the upper and inner layers and the damage threshold value of the substrate were investigated using a pulsed fiber laser. To obtain experimental evidence, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and 3D surface profilometry were employed to investigate the two kinds of sulfide layers on specimens before, during, and after laser cleaning.

  6. Thermodynamics of Complex Sulfide Inclusion Formation in Ca-Treated Al-Killed Structural Steel

    Science.gov (United States)

    Guo, Yin-tao; He, Sheng-ping; Chen, Gu-jun; Wang, Qian

    2016-05-01

    Controlling the morphology of the sulfide inclusion is of vital importance in enhancing the properties of structural steel. Long strip-shaped sulfides in hot-rolled steel can spherize when, instead of the inclusion of pure single-phase MnS, the guest is a complex sulfide, such as an oxide-sulfide duplex and a solid-solution sulfide particle. In this study, the inclusions in a commercial rolled structural steel were investigated. Spherical and elongated oxide-sulfide duplex as well as single-phase (Mn,Ca)S solid solution inclusions were observed in the steel. A thermodynamic equilibrium between the oxide and sulfide inclusions was proposed to understand the oxide-sulfide duplex inclusion formation. Based on the equilibrium solidification principle, thermodynamic discussions on inclusion precipitation during the solidification process were performed for both general and resulfurized structural steel. The predicted results of the present study agreed well with the experimental ones.

  7. Thermodynamics of Complex Sulfide Inclusion Formation in Ca-Treated Al-Killed Structural Steel

    Science.gov (United States)

    Guo, Yin-tao; He, Sheng-ping; Chen, Gu-jun; Wang, Qian

    2016-08-01

    Controlling the morphology of the sulfide inclusion is of vital importance in enhancing the properties of structural steel. Long strip-shaped sulfides in hot-rolled steel can spherize when, instead of the inclusion of pure single-phase MnS, the guest is a complex sulfide, such as an oxide-sulfide duplex and a solid-solution sulfide particle. In this study, the inclusions in a commercial rolled structural steel were investigated. Spherical and elongated oxide-sulfide duplex as well as single-phase (Mn,Ca)S solid solution inclusions were observed in the steel. A thermodynamic equilibrium between the oxide and sulfide inclusions was proposed to understand the oxide-sulfide duplex inclusion formation. Based on the equilibrium solidification principle, thermodynamic discussions on inclusion precipitation during the solidification process were performed for both general and resulfurized structural steel. The predicted results of the present study agreed well with the experimental ones.

  8. Morphology and thermal studies of zinc sulfide and cadmium sulfide nanoparticles in polyvinyl alcohol matrix

    Science.gov (United States)

    Osuntokun, Jejenija; Ajibade, Peter A.

    2016-09-01

    Zn(II) and Cd(II) metal complexes of 1-cyano-1-carboethoxyethylene-2,2-dithiolato-κS,S'-bis(N,N-dimethylthiourea-κS) have been synthesized and characterized with analytical and spectroscopic techniques. The complexes were thermolysed in hexadecylamine at 200 °C to prepare ZnS and CdS nanoparticles. The nanoparticles were characterized with scanning electron microscope (SEM), transmission electron microscope (TEM), and powder X-ray diffraction (p-XRD). TEM images showed spherically shaped nanoparticles, whose sizes are in the range 4.33-7.21 nm for ZnS and 4.95-7.7 nm CdS respectively and XRD confirmed cubic crystalline phases for the nanoparticles. The optical band gap energy evaluated from the absorption spectra are 2.88 eV (430 nm) and 2.81 eV (440 nm) for the ZnS and CdS nanoparticles respectively. The as-prepared metal sulfide nanoparticles were further incorporated into polyvinyl alcohol (PVA) to give ZnS/PVA and CdS/PVA composites. The polymer nanocomposites were studied to investigate their morphology and thermal properties relative to the pure PVA. XRD diffractions indicated that the crystalline phases of the nanoparticles and the sizes in PVA matrices remained unaltered. Infra-red spectra studies revealed interactions between the PVA and the metal sulfide nanoparticles and TGA studies show that the ZnS/PVA and CdS/PVA nanocomposites exhibit better thermal stability than the pure PVA.

  9. Application of Borehole SIP Technique to Sulfide Mineral Exploration

    Science.gov (United States)

    Kim, Changryol; Park, Mi Kyung; Park, Samgyu; Sung, Nak Hoon; Shin, Seung Wook

    2016-04-01

    In the study, SIP (Spectral Induced Polarization) well logging probe system was developed to rapidly locate the metal ore bodies with sulfide minerals in the boreholes. The newly developed SIP logging probe employed the non-polarizable electrodes, consisting of zinc chloride (ZnCl2), sodium chloride (NaCl), gypsum (CaSO4·2H2O), and water (H2O), instead of existing copper electrodes, leading to eliminating the EM coupling effect in the IP surveys as much as possible. In addition, the SIP logging system is designed to make measurements down to maximum 500 meters in depth in the boreholes. The SIP well logging was conducted to examine the applicability of the SIP probe system to the boreholes at the ore mine in Jecheon area, Korea. The boreholes used in the SIP logging are known to have penetrated the metal ore bodies with sulfide minerals from the drilling investigations. The ore mine of the study area is the scarn deposits surrounded by the limestone or lime-silicate rocks in Ordovician period. The results of the SIP well logging have shown that the borehole segments with limestone or lime-silicate rocks yielded the insignificant SIP responses while the borehole segments with sulfide minerals (e.g. pyrite) provided the significant phase shifts of the SIP responses. The borehole segments penetrating the metal ore body, so-called cupola, have shown very high response of the phase shift, due to the high contents of the sulfide mineral pyrite. The phase shifts of the SIP response could be used to estimate the grade of the ore bodies since the higher contents of the sulfide minerals, the higher magnitudes of the phase shifts in the SIP responses. It is, therefore, believed that the borehole SIP technique can be applied to investigate the metal ore bodies with sulfide minerals, and that could be used to estimate the ore grades as a supplementary tool in the future.

  10. Hydrogen evolution from water through metal sulfide reactions

    International Nuclear Information System (INIS)

    Transition metal sulfides play an important catalytic role in many chemical reactions. In this work, we have conducted a careful computational study of the structures, electronic states, and reactivity of metal sulfide cluster anions M2SX− (M = Mo and W, X = 4–6) using density functional theory. Detailed structural analysis shows that these metal sulfide anions have ground state isomers with two bridging sulfide bonds, notably different in some cases from the corresponding oxides with the same stoichiometry. The chemical reactivity of these metal sulfide anions with water has also been carried out. After a thorough search on the reactive potential energy surface, we propose several competitive, energetically favorable, reaction pathways that lead to the evolution of hydrogen. Selectivity in the initial water addition and subsequent hydrogen migration are found to be the key steps in all the proposed reaction channels. Initial adsorption of water is most favored involving a terminal metal sulfur bond in Mo2S4− isomers whereas the most preferred orientation for water addition involves a bridging metal sulfur bond in the case of W2S4− and M2S5− isomers. In all the lowest energy H2 elimination steps, the interacting hydrogen atoms involve a metal hydride and a metal hydroxide (or thiol) group. We have also observed a higher energy reaction channel where the interacting hydrogen atoms in the H2 elimination step involve a thiol (–SH) and a hydroxyl (–OH) group. For all the reaction pathways, the Mo sulfide reactions involve a higher barrier than the corresponding W analogues. We observe for both metals that reactions of M2S4− and M2S5− clusters with water to liberate H2 are exothermic and involve modest free energy barriers. However, the reaction of water with M2S6− is highly endothermic with a considerable barrier due to saturation of the local bonding environment

  11. Vegetation successfully prevents oxidization of sulfide minerals in mine tailings.

    Science.gov (United States)

    Li, Yang; Sun, Qingye; Zhan, Jing; Yang, Yang; Wang, Dan

    2016-07-15

    The oxidization of metal sulfide in tailings causes acid mine drainage. However, it remains unclear whether vegetation prevents the oxidization of metal sulfides. The oxidization characteristics and microbial indices of the tailings in the presence of various plant species were investigated to explore the effects of vegetation on the oxidization of sulfide minerals in tailings. The pH, reducing sulfur, free iron oxides (Fed), chemical oxygen consumption (COC) and biological oxygen consumption (BOC) were measured. Key iron- and sulfur-oxidizing bacteria (Acidithiobacillus spp., Leptospirillum spp. and Thiobacillus spp.) were quantified using real-time PCR. The results indicate that vegetation growing on tailings can effectively prevent the oxidization of sulfide minerals in tailings. A higher pH and reducing-sulfur content and lower Fed were observed in the 0-30 cm depth interval in the presence of vegetation compared to bare tailings (BT). The COC gradually decreased with depth in all of the soil profiles; specifically, the COC rapidly decreased in the 10-20 cm interval in the presence of vegetation but gradually decreased in the BT profiles. Imperata cylindrica (IC) and Chrysopogon zizanoides (CZ) profiles contained the highest BOC in the 10-20 cm interval. The abundance of key iron- and sulfur-oxidizing bacteria in the vegetated tailings were significantly lower than in the BT; in particular, IC was associated with the lowest iron- and sulfur-oxidizing bacterial abundance. In conclusion, vegetation successfully prevented the oxidization of sulfide minerals in the tailings, and Imperata cylindrica is the most effective in reducing the number of iron- and sulfur-oxidizing bacteria and helped to prevent the oxidization of sulfide minerals in the long term. PMID:27093236

  12. The Sulfide Capacity of Iron Oxide-Rich Slags

    Science.gov (United States)

    Motlagh, M.

    1988-03-01

    The relationship between the sulfide capacity of slags rich in iron oxide and the sulfur partition ratio between the metal and slag is strongly related to the slag's iron oxide concentration. For slags containing little or no lime, this relationship is linear for a constant concentration of iron oxide in the slag. The effect of silica on changes in the sulfide capacity of slags rich in iron oxide is similar to that of basic steel-making slags, particularly at low activity of silica in slag.

  13. Experimental constraints on gold and silver solubility in iron sulfides

    Energy Technology Data Exchange (ETDEWEB)

    Pal' yanova, Galina [Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, 3, Koptyuga, Novosibirsk, 630090 (Russian Federation); Novosibirsk State University, Russia, 2, Pirogova, Novosibirsk, 630090 (Russian Federation); Mikhlin, Yuri [Institute of Chemistry and Chemical Technology, Siberian Branch of the Russian Academy of Sciences, Akademgorodok, 50/24, Krasnoyarsk, 660036 (Russian Federation); Kokh, Konstantin, E-mail: k.a.kokh@gmail.com [Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, 3, Koptyuga, Novosibirsk, 630090 (Russian Federation); Novosibirsk State University, Russia, 2, Pirogova, Novosibirsk, 630090 (Russian Federation); Siberian Physical–Technical Institute of Tomsk State University, 1, Novosobornaya, Tomsk, 634050 (Russian Federation); Karmanov, Nick [Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, 3, Koptyuga, Novosibirsk, 630090 (Russian Federation); Seryotkin, Yurii [Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, 3, Koptyuga, Novosibirsk, 630090 (Russian Federation); Novosibirsk State University, Russia, 2, Pirogova, Novosibirsk, 630090 (Russian Federation)

    2015-11-15

    Experiments were performed to determine crystallization of Fe,S-melts (pyriti≿ and troilitic with molar ratio S/Fe ratios of 2 and 1, respectively) containing traces of gold and silver at (Ag/Au){sub wt} ratios varying from 10 to 0.1. The solid products were studied by optical microscopy, scanning electron microscopy, X-ray powder diffraction (XRD), microprobe analysis, and X-ray photoelectron spectroscopy (XPS) in order to reveal the concentration limits of “invisible” gold and silver in magmatic iron sulfides, and to determine the influence of sulfur on forms of precious metals in the Fe–S system with different Ag/Au ratios. Au–Ag phases do not form inclusions but instead concentrate on the grain boundaries in the synthetic pyrrhotite and troilite, while pyrite comprises micro- (1–5 μm) and macroinclusions of Au–Ag alloys and Au–Ag sulfides. In “pyriti≿” systems, the fineness of alloys increases from 650 to 970‰ and the composition of sulfides changes from acanthite (Ag{sub 2}S) to uytenbogaardtite (Ag{sub 3}AuS{sub 2}) and petrovskaite (AgAuS) as the Ag/Au ratio decreases. The concentrations of “invisible” precious metals revealed in troilite were 0.040 ± 0.013 wt.% Au and 0.079 ± 0.016 wt.% Ag. Measured concentrations in pyrite and pyrrhotite were <0.024 wt.% Au and <0.030 wt.% Ag. The surface layers of iron sulfides probed with XPS were enriched in the precious metals, and in silver relative to gold, especially in the systems with Fe/S = 1, probably, due to depletion of the metallic alloy surfaces with gold. Au- and Ag-bearing iron sulfides crystallized primarily from melts may be the source of redeposited phases in hydrothermal and hypergene processes. - Highlights: • The samples of Fe–S–Au–Ag system were synthesized. • Coupled solubility of gold and silver in iron sulfides was specified. • Ag–Au inclusions on surfaces of iron sulfides are likely to be enriched in silver. • Au–Ag sulfides can exist along with

  14. Non-hydrolytic Sol-gel Synthesis of Tin Sulfides

    Science.gov (United States)

    Kaur, Rajvinder

    The non-hydrolytic sol-gel (NHSG) process is an effective low temperature route well known for preparing homogeneous metal oxides. Thermodynamically as well as kinetically favored products, which cannot be prepared with the traditional solid-state routes, can be produced using NHSG. This project is focused on the exploration of NHSG synthesis of binary tin sulfides. In the past few years, metal sulfides have been the subject of significant interest. Much effort has been devoted to understand these materials because of their potential applications in electronic, optical, and superconductor devices.4 Among these materials, tin sulfides are materials of technological importance, which are being explored as semiconductors, anode materials for Li ion batteries, photoconductors, photocatalysts and absorber layer materials in photovoltaic solar cell devices. All of these applications depend upon features like homogeneity, oxidation state, high surface area and purity of the materials. These properties can be difficult to achieve by employing traditional synthetic routes, which require high temperatures due to slow diffusion, limiting the products to thermodynamically stable phases and prohibiting control over properties like particle size and surface area. A variety of low temperature methods are being explored due to the increased demand for such advanced materials. This project is focused on exploring the NHSG approach to synthesize binary tin sulfides, with the main goal of establishing conditions for the targeted synthesis of different tin sulfide polymorphs with controlled particle size. Being non-oxide materials, tin sulfides can be air sensitive, which requires special attention in handling. All reactions were carried out in absence of oxygen. This project explores the reaction of tin halides with thioethers in a dry solvent medium, leading to the formation of tin sulfides. There are a number of synthetic parameters that can be varied for the NHSG approach. A

  15. Experimental constraints on gold and silver solubility in iron sulfides

    International Nuclear Information System (INIS)

    Experiments were performed to determine crystallization of Fe,S-melts (pyriti≿ and troilitic with molar ratio S/Fe ratios of 2 and 1, respectively) containing traces of gold and silver at (Ag/Au)wt ratios varying from 10 to 0.1. The solid products were studied by optical microscopy, scanning electron microscopy, X-ray powder diffraction (XRD), microprobe analysis, and X-ray photoelectron spectroscopy (XPS) in order to reveal the concentration limits of “invisible” gold and silver in magmatic iron sulfides, and to determine the influence of sulfur on forms of precious metals in the Fe–S system with different Ag/Au ratios. Au–Ag phases do not form inclusions but instead concentrate on the grain boundaries in the synthetic pyrrhotite and troilite, while pyrite comprises micro- (1–5 μm) and macroinclusions of Au–Ag alloys and Au–Ag sulfides. In “pyriti≿” systems, the fineness of alloys increases from 650 to 970‰ and the composition of sulfides changes from acanthite (Ag2S) to uytenbogaardtite (Ag3AuS2) and petrovskaite (AgAuS) as the Ag/Au ratio decreases. The concentrations of “invisible” precious metals revealed in troilite were 0.040 ± 0.013 wt.% Au and 0.079 ± 0.016 wt.% Ag. Measured concentrations in pyrite and pyrrhotite were <0.024 wt.% Au and <0.030 wt.% Ag. The surface layers of iron sulfides probed with XPS were enriched in the precious metals, and in silver relative to gold, especially in the systems with Fe/S = 1, probably, due to depletion of the metallic alloy surfaces with gold. Au- and Ag-bearing iron sulfides crystallized primarily from melts may be the source of redeposited phases in hydrothermal and hypergene processes. - Highlights: • The samples of Fe–S–Au–Ag system were synthesized. • Coupled solubility of gold and silver in iron sulfides was specified. • Ag–Au inclusions on surfaces of iron sulfides are likely to be enriched in silver. • Au–Ag sulfides can exist along with native gold in pyrite

  16. Dithiocarbamate Complexes as Single Source Precursors to Metal Sulfide Nanoparticles for Applications in Catalysis

    OpenAIRE

    Roffey, A. R.

    2014-01-01

    Herein we report the solvothermal decomposition of a range of metal dithiocarbamate complexes for the synthesis of metal sulfide nanoparticles. Metal sulfides exist in a variety of structural phases, some of which are known to be catalytically active towards various processes. The aim of this work was to synthesise a variety of different metal sulfide phases for future catalysis testing, particularly the iron sulfide greigite (Fe3S4, a thiospinel containing Fe2+ and Fe3+) which is to be teste...

  17. Identifying the Prospective Area of Sulfide Groundwater within the Area of Palvantash Oil and Gas Deposit

    Directory of Open Access Journals (Sweden)

    M. R. Zhurayev

    2014-03-01

    Full Text Available This paper describes the methodology of prospecting for sulfide groundwater in the area of Palvantash oil fields. In result of study allowed determining the favorable conditions for the sulfide waters formation, and mapping the areas of different sulfide water concentration. The relatively permeable areas were established and the water borehole positions were recommended.

  18. 76 FR 64022 - Hydrogen Sulfide; Community Right-to-Know Toxic Chemical Release Reporting

    Science.gov (United States)

    2011-10-17

    ... rule (December 1, 1993, 58 FR 63500). Hydrogen sulfide was listed under the criteria of EPCRA section... EPCRA section 313(d)(2)(B) (see 59 FR 61432, 61433, 61440-61442). Hydrogen sulfide has also been... adding hydrogen sulfide to the EPCRA section 313 list of toxic chemicals (58 FR 63500) (effective...

  19. Selective precipitation of heavy metals as controlled by a sulfide-selective electrode

    NARCIS (Netherlands)

    Veeken, A.H.M.; Vries, S.; Mark, van der A.

    2003-01-01

    Sulfide precipitation is superior to hydroxide precipitation for removal of heavy metals from wastewaters as it results in lower effluent concentrations and less interference from chelating agents. However, sulfide precipitation is not widely applied in practice because the dosing of sulfide cannot

  20. Sulfide-iron interactions in domestic wastewater from a gravity sewer

    NARCIS (Netherlands)

    Nielsen, A.H.; Lens, P.N.L.; Vollertsen, J.; Hvitved-Jacobsen, Th.

    2005-01-01

    Interactions between iron and sulfide in domestic wastewater from a gravity sewer were investigated with particular emphasis on redox cycling of iron and iron sulfide formation. The concentration ranges of iron and total sulfide in the experiments were 0.4-5.4 mg Fe L-1 and 0-5.1 mg S L-1, respectiv

  1. SULFIDE OXIDATION UNDER OXYGEN LIMITATION BY A THIOBACILLUS-THIOPARUS ISOLATED FROM A MARINE MICROBIAL MAT

    NARCIS (Netherlands)

    VANDENENDE, FP; VANGEMERDEN, H

    1993-01-01

    The colorless sulfur bacterium Thiobacillus thioparus T5, isolated from a marine microbial mat, was grown in continuous culture under conditions ranging from sulfide limitation to oxygen limitation. Under sulfide-limiting conditions, sulfide was virtually completely oxidized to sulfate. Under oxygen

  2. Thermochemical hydrogen production via a cycle using barium and sulfur - Reaction between barium sulfide and water

    Science.gov (United States)

    Ota, K.; Conger, W. L.

    1977-01-01

    The reaction between barium sulfide and water, a reaction found in several sulfur based thermochemical cycles, was investigated kinetically at 653-866 C. Gaseous products were hydrogen and hydrogen sulfide. The rate determining step for hydrogen formation was a surface reaction between barium sulfide and water. An expression was derived for the rate of hydrogen formation.

  3. H2S exposure elicits differential expression of candidate genes in fish adapted to sulfidic and non-sulfidic environments.

    Science.gov (United States)

    Tobler, Michael; Henpita, Chathurika; Bassett, Brandon; Kelley, Joanna L; Shaw, Jennifer H

    2014-09-01

    Disentangling the effects of plasticity, genetic variation, and their interactions on organismal responses to environmental stressors is a key objective in ecological physiology. We quantified the expression of five candidate genes in response to hydrogen sulfide (H2S) exposure in fish (Poecilia mexicana, Poeciliidae) from a naturally sulfide-rich environment as well as an ancestral, non-sulfidic population to test for constitutive and environmentally dependent population differences in gene expression patterns. Common garden raised individuals that had never encountered environmental H2S during their lifetime were subjected to short or long term H2S exposure treatments or respective non-sulfidic controls. The expression of genes involved in responses to H2S toxicity (cytochrome c oxidase, vascular endothelial growth factor, and cytochrome P450-2J6), H2S detoxification (sulfide:quinone oxidoreductase), and endogenous H2S production (cystathionine γ lyase) was determined in both gill and liver tissues by real time PCR. The results indicated complex changes in expression patterns that--depending on the gene--not only differed between organs and populations, but also on the type of H2S exposure. Populations differences, both constitutive and H2S exposure dependent (i.e., plastic), in gene expression were particularly evident for sulfide:quinone oxidoreductase, vascular endothelial growth factor, and to a lesser degree for cytochrome P450-2J6. Our study uncovered putatively adaptive modifications in gene regulation that parallel previously documented adaptive changes in phenotypic traits. PMID:24813672

  4. The structure of Aquifex aeolicus sulfide:quinone oxidoreductase, a basis to understand sulfide detoxification and respiration

    OpenAIRE

    Marcia, Marco; Ermler, Ulrich; Peng, Guohong; Michel, Hartmut

    2009-01-01

    Sulfide:quinone oxidoreductase (SQR) is a flavoprotein with homologues in all domains of life except plants. It plays a physiological role both in sulfide detoxification and in energy transduction. We isolated the protein from native membranes of the hyperthermophilic bacterium Aquifex aeolicus, and we determined its X-ray structure in the “as-purified,” substrate-bound, and inhibitor-bound forms at resolutions of 2.3, 2.0, and 2.9 Å, respectively. The structure is composed of 2 Rossmann doma...

  5. Hydrogen sulfide : role in vascular physiology and pathology

    NARCIS (Netherlands)

    Holwerda, Kim M.; Karumanchi, S. Ananth; Lely, A. Titia

    2015-01-01

    Purpose of reviewHydrogen sulfide (H2S), a colorless gas that is endogenously generated in mammals from cysteine, has important biological functions. Within the vasculature it regulates vessel tone and outgrowth of new vessels. This review summarizes recent literature on H2S signaling in the vascula

  6. Alloy selection for sulfidation: oxidation resistance in coal gasification environments

    Energy Technology Data Exchange (ETDEWEB)

    Bradshaw, R.W.; Stoltz, R.E.

    1980-01-01

    A series of iron-nickel-chromium and nickel-chromium alloys were studied for their combined sulfidation-oxidation resistance in simulated coal gasification environments. All alloys contained a minimum of 20 w/o chromium, and titanium and aluminum in the range 0 to 4 w/o. Corrosion resistance was evaluated at 1255/sup 0/K (1800/sup 0/F) in both high BTU and low BTU coal gasification atmospheres with 1 v/o H/sub 2/S. Titanium at levels greater than 1 w/o imparted significant sulfidation resistance due to an adherent, solid solution chromium-titanium oxide layer which prevented sulfur penetration. Aluminum was less effective in preventing sulfidation since surface scales were not adherent. Of the commercial alloys tested, Nimomic 81, Pyromet 31, IN801, and IN825 exhibited the best overall corrosion resistance. However, futher alloy development, tailored to produce solid solution chromium-titanium oxide scales, may lead to alloys with greater sulfidation-oxidation resistance than those investigated here.

  7. Adsorption characteristics of thiobacillus ferrooxidans on surface of sulfide minerals

    Institute of Scientific and Technical Information of China (English)

    LIU Jian-she; XIE Xue-hui; LI Bang-mei; DONG Qing-hai

    2005-01-01

    By using thiobacillus ferrooxidans (T.f) from Qixiashan, Hubei Province, China, the adsorption characteristics of T.f on surface of sulfide mineral were studied. The influences of adsorption time, pH value, temperature, initial inoculated concentration of bacteria, concentration of sulfide mineral powder, and variety of minerals on the adsorption characteristics were firstly investigated by using the ninhydrin colorimetric method, and the changes of contact angles and Zeta potentials of mineral surface during the bacterial adsorption were then determined. The results show that when the leaching experiments are performed for a long time from several days to a month, the maximal quantity of adsorption of T.f on the surface of pyrite is obtained under the following conditions: leaching for 20 d, pH value in range of 1-2 and temperature at 30 ℃, respectively; when the bio-leaching experiments are performed for a shorter leaching time, the maximal quantity of adsorption is obtained under the conditions: bio-leaching for 2 h, at 2.4×10 7 cell/mL of initial inoculated bacteria concentration, and at 10% of mineral powder concentration; and the adsorption quantities are different form one sulfide mineral to another, and the adsorption of T.f on the surface of sulfide minerals includes three phases: increasing phase, stationary phase and decreasing phase.

  8. Luminescence in Sulfides: A Rich History and a Bright Future

    Directory of Open Access Journals (Sweden)

    Philippe F. Smet

    2010-04-01

    Full Text Available Sulfide-based luminescent materials have attracted a lot of attention for a wide range of photo-, cathodo- and electroluminescent applications. Upon doping with Ce3+ and Eu2+, the luminescence can be varied over the entire visible region by appropriately choosing the composition of the sulfide host. Main application areas are flat panel displays based on thin film electroluminescence, field emission displays and ZnS-based powder electroluminescence for backlights. For these applications, special attention is given to BaAl2S4:Eu, ZnS:Mn and ZnS:Cu. Recently, sulfide materials have regained interest due to their ability (in contrast to oxide materials to provide a broad band, Eu2+-based red emission for use as a color conversion material in white-light emitting diodes (LEDs. The potential application of rare-earth doped binary alkaline-earth sulfides, like CaS and SrS, thiogallates, thioaluminates and thiosilicates as conversion phosphors is discussed. Finally, this review concludes with the size-dependent luminescence in intrinsic colloidal quantum dots like PbS and CdS, and with the luminescence in doped nanoparticles.

  9. A coumarin-based colorimetric fluorescent probe for hydrogen sulfide

    Indian Academy of Sciences (India)

    Yanqiu Yang; Yu Liu; Liang Yang; Jun Liu; Kun Li; Shunzhong Luo

    2015-03-01

    A coumarin-based fluorescent probe for selective detection of hydrogen sulfide (H2S) is presented. This `off–on’ probe exhibited high selectivity towards H2S in aqueous solution with a detection limit of 30 nM. Notably, because of its dual nucleophilicity, the probe could avoid the interference of thiols and other sulfur containing compounds.

  10. Estimation of bacterial hydrogen sulfide production in vitro

    Directory of Open Access Journals (Sweden)

    Amina Basic

    2015-06-01

    Full Text Available Oral bacterial hydrogen sulfide (H2S production was estimated comparing two different colorimetric methods in microtiter plate format. High H2S production was seen for Fusobacterium spp., Treponema denticola, and Prevotella tannerae, associated with periodontal disease. The production differed between the methods indicating that H2S production may follow different pathways.

  11. Synthesis and photovoltaic application of coper (I) sulfide nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Yue; Wadia, Cyrus; Ma, Wanli; Sadtler, Bryce; Alivisatos, A.Paul

    2008-06-24

    We present the rational synthesis of colloidal copper(I) sulfide nanocrystals and demonstrate their application as an active light absorbing component in combination with CdS nanorods to make a solution-processed solar cell with 1.6percent power conversion efficiency on both conventional glass substrates and flexible plastic substrates with stability over a 4 month testing period.

  12. Electrogenerative leaching of nickel sulfide concentrate with ferric chloride

    Institute of Scientific and Technical Information of China (English)

    王少芬; 方正; 王云燕; 陈阳国

    2004-01-01

    In order to utilize the chemical energy in hydrometallurgical process of sulfide minerals reasonably and to simplify the purifying process, the electrogenerative process was applied and a dual cell system was introduced to investigate FeCl3 leaching of nickel sulfide concentrate. Some factors influencing the electrogenerative leaching, such as electrode structure, temperature and solution concentration were studied. The results show that a certain quantity of electrical energy accompanied with the leached products can be acquired in the electrogenerative leaching process.The output current and power increase with the addition of acetylene black to the electrode. Varying the components of electrode just affects the polarization degree of anode. Increasing FeCl3 concentration results in a sharp increase in the output of the leaching cell when c(FeCl3) is less than 0.1 mol/L. The optimum value of NaCl concentration for electrogenerative leaching nickel sulfide concentrate with FeCl3 is 3.0 mol/L. Temperature influences electrogenerative leaching by affecting anodic and cathodic polarization simultaneously. The apparent activation energy is determined to be 34.63 kJ/mol in the range of 298 K to 322 K. The leaching rate of Ni2+ is 29.3% after FeCl3 electrogenerative leaching of nickel sulfide concentrate for 620 min with a filter bag electrode.

  13. Microbial Oxidation of Iron Sulfides in Anaerobic Environments

    DEFF Research Database (Denmark)

    Vaclavkova, Sarka

    Abstract (shortened): Iron sulfides (FeSx), representing 0.04-10 % of Danish dry soil weight, oxidize in a presence of oxygen, releasing sulfuric acid and free iron. Environmental impact of FeSx oxidation is commonly seen on agricultural sites cultivated by drainage as acid sulfate soil formation...

  14. 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.

  15. Magmatic sulfides in the porphyritic chondrules of EH enstatite chondrites

    CERN Document Server

    Piani, Laurette; Libourel, Guy; Tissandier, Laurent

    2016-01-01

    The nature and distribution of sulfides within 17 porphyritic chondrules of the Sahara 97096 EH3 enstatite chondrite have been studied by backscattered electron microscopy and electron microprobe in order to investigate the role of gas-melt interactions in the chondrule sulfide formation. Troilite (FeS) is systematically present and is the most abundant sulfide within the EH3 chondrite chondrules. It is found either poikilitically enclosed in low-Ca pyroxenes or scattered within the glassy mesostasis. Oldhamite (CaS) and niningerite [(Mg,Fe,Mn)S] are present in about 60% of the chondrules studied. While oldhamite is preferentially present in the mesostasis, niningerite associated with silica is generally observed in contact with troilite and low-Ca pyroxene. The chondrule mesostases contain high abundances of alkali and volatile elements as well as silica. Our data suggest that most of the sulfides found in EH3 chondrite chondrules are magmatic minerals that formed after the dissolution of S from a volatile-r...

  16. Adsorption of hydrogen sulfide on montmorillonites modified with iron.

    Science.gov (United States)

    Nguyen-Thanh, Danh; Block, Karin; Bandosz, Teresa J

    2005-04-01

    Sodium-rich montmorillonite was modified with iron in order to introduce active centers for hydrogen sulfide adsorption. In the first modification, interlayer sodium cations were exchanged with iron. In another modification, iron oxocations were introduced to the clay surface. The most elaborated modification was based on doping of iron within the interlayer space of aluminum-pillared clay. The modified clay samples were tested as hydrogen sulfide adsorbents. Iron-doped samples showed a significant improvement in the capacity for H2S removal, despite of a noticeable decrease in microporosity compared to the initial pillared clay. The smallest capacity was obtained for the clay modified with iron oxocations. Variations in adsorption capacity are likely due to differences in the chemistry of iron species, degree of their dispersion on the surface, and accessibility of small pores for H2S molecule. The results suggest that on the surface of iron-modified clay hydrogen sulfide reacts with Fe(+3) forming sulfides or it is catalytically oxidized to SO2 on iron (hydro)oxides. Subsequent oxidation may lead to sulfate formation.

  17. Solar thermal extraction of copper and zinc from sulfides

    Energy Technology Data Exchange (ETDEWEB)

    Guesdon, C.; Sturzenegger, M.

    2002-03-01

    A novel approach for extracting metals from metal sulfides is proposed. Key feature is the use of concentrated solar radiation to directly convert metal sulfides into the metal and sulfur. Such processes have the potential to produce metals with virtually zero emission of SO{sub 2} and CO{sub 2}. The feasibility of such a solar thermal extraction has been evaluated for zinc sulfide (Zn S) and copper(I)sulfide Cu{sub 2}S. Thermodynamic calculations suggest that for both processes heat recovery from the hot product is required to implement a viable process. Decomposition experiments have indicated that the high reactivity of Zn and S is not compatible with the energy requirement of heat recovery and that quenching will likely be needed to collect Zn. As an alternative, the addition of a mixture of O{sub 2} and steam (chemical quenching) is discussed. The extraction of Cu from Cu{sub 2}S appears less critical: Experiments under N{sub 2} revealed the formation of metallic Cu already at 1323 K. Natural separation of gaseous S from liquid Cu successfully prevents recombination of the two products and at least partial heat recovery can be envisaged. (author)

  18. ISE Analysis of Hydrogen Sulfide in Cigarette Smoke

    Science.gov (United States)

    Li, Guofeng; Polk, Brian J.; Meazell, Liz A.; Hatchett, David W.

    2000-08-01

    Many advanced undergraduate analytical laboratory courses focus on exposing students to various modern instruments. However, students rarely have the opportunity to construct their own analytical tools for solving practical problems. We designed an experiment in which students are required to build their own analytical module, a potentiometric device composed of a Ag/AgCl reference electrode, a Ag/Ag2S ion selective electrode (ISE), and a pH meter used as voltmeter, to determine the amount of hydrogen sulfide in cigarette smoke. Very simple techniques were developed for constructing these electrodes. Cigarette smoke is collected by a gas washing bottle into a 0.1 M NaOH solution. The amount of sulfide in the cigarette smoke solution is analyzed by standard addition of sulfide solution while monitoring the response of the Ag/Ag2S ISE. The collected data are further evaluated using the Gran plot technique to determine the concentration of sulfide in the cigarette smoke solution. The experiment has been successfully incorporated into the lab course Instrumental Analysis at Georgia Institute of Technology. Students enjoy the idea of constructing an analytical tool themselves and applying their classroom knowledge to solve real-life problems. And while learning electrochemistry they also get a chance to visualize the health hazard imposed by cigarette smoking.

  19. Micelle Mediated Trace Level Sulfide Quantification through Cloud Point Extraction

    Directory of Open Access Journals (Sweden)

    Samrat Devaramani

    2012-01-01

    Full Text Available A simple cloud point extraction protocol has been proposed for the quantification of sulfide at trace level. The method is based on the reduction of iron (III to iron (II by the sulfide and the subsequent complexation of metal ion with nitroso-R salt in alkaline medium. The resulting green-colored complex was extracted through cloud point formation using cationic surfactant, that is, cetylpyridinium chloride, and the obtained surfactant phase was homogenized by ethanol before its absorbance measurement at 710 nm. The reaction variables like metal ion, ligand, surfactant concentration, and medium pH on the cloud point extraction of the metal-ligand complex have been optimized. The interference effect of the common anions and cations was studied. The proposed method has been successfully applied to quantify the trace level sulfide in the leachate samples of the landfill and water samples from bore wells and ponds. The validity of the proposed method has been studied by spiking the samples with known quantities of sulfide as well as comparing with the results obtained by the standard method.

  20. Sulfide Formation And Its Impacts On A Developing Country

    DEFF Research Database (Denmark)

    Matias, Natércia; Mutuvúie, Raúl; Vollertsen, Jes;

    2014-01-01

    is expected in the near future, with the associated longer wastewater travel times and increasing problems of septicity and hydrogen sulfide gas impacts. In order to better understand the in-sewer processes under local conditions, evaluate risks and exemplify how to support general drainage systems planning...

  1. Potential Applications of Hydrogen Sulfide-Induced Suspended Animation

    NARCIS (Netherlands)

    H. Aslami; M.J. Schultz; N.P. Juffermans

    2009-01-01

    A suspended animation-like state has been induced in rodents with the use of hydrogen sulfide, resulting in hypothermia with a concomitant reduction in metabolic rate. Also oxygen demand was reduced, thereby protecting against hypoxia. Several therapeutic applications of induction of a hibernation-l

  2. Hydrogen sulfide : physiological properties and therapeutic potential in ischaemia

    NARCIS (Netherlands)

    Bos, Eelke M.; van Goor, Harry; Joles, Jaap A.; Whiteman, Matthew; Leuvenink, Henri G. D.

    2015-01-01

    Hydrogen sulfide (H2S) has become a molecule of high interest in recent years, and it is now recognized as the third gasotransmitter in addition to nitric oxide and carbon monoxide. In this review, we discuss the recent literature on the physiology of endogenous and exogenous H2S, focusing upon the

  3. Hydrogen sulfide release from dairy manure storages containing gypsum bedding

    Science.gov (United States)

    Recycled gypsum products can provide a cost-effective bedding alternative for dairy producers. Manufacturers report reduced odors, moisture and bacteria in the stall environment when compared to traditional bedding. Gypsum provides a sulfate source that can be converted to hydrogen sulfide under ana...

  4. 40 CFR 425.04 - Applicability of sulfide pretreatment standards.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 29 2010-07-01 2010-07-01 false Applicability of sulfide pretreatment standards. 425.04 Section 425.04 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS LEATHER TANNING AND FINISHING POINT SOURCE CATEGORY General Provisions § 425.04 Applicability of...

  5. Carbonyl Sulfides as Possible Intermediates in the Photolysis of Oxathiiranes

    DEFF Research Database (Denmark)

    Carlsen, Lars; Snyder, J. P.; Holm, A.;

    1981-01-01

    species and several dipolarophiles is rationlized in terms of a labile carbonyl suffide intermediate capable of facile sulfur extrusion from a long, weak O-S bond. Finally, the electronic absorption spectra of a series of para-substituted benzaldehyde O-sulfide model system have been calculated with CNDO...

  6. Volcanogenic massive sulfide occurrence model: Chapter C in Mineral deposit models for resource assessment

    Science.gov (United States)

    Shanks, W.C. Pat; Koski, Randolph A.; Mosier, Dan L.; Schulz, Klaus J.; Morgan, Lisa A.; Slack, John F.; Ridley, W. Ian; Dusel-Bacon, Cynthia; Seal, Robert R., II; Piatak, Nadine M.; Shanks, W.C. Pat; Thurston, Roland

    2012-01-01

    Volcanogenic massive sulfide deposits, also known as volcanic-hosted massive sulfide, volcanic-associated massive sulfide, or seafloor massive sulfide deposits, are important sources of copper, zinc, lead, gold, and silver (Cu, Zn, Pb, Au, and Ag). These deposits form at or near the seafloor where circulating hydrothermal fluids driven by magmatic heat are quenched through mixing with bottom waters or porewaters in near-seafloor lithologies. Massive sulfide lenses vary widely in shape and size and may be podlike or sheetlike. They are generally stratiform and may occur as multiple lenses.

  7. Direct rapid determination of traces of sulfide in environment samples

    Institute of Scientific and Technical Information of China (English)

    郭方遒; 黄兰芳; 梁逸曾

    2002-01-01

    An improved ethylene blue method for determination of sulfide is developed. It has been adapted to a direct determination of sulfide by both common spectrophotometric method and total differential spectrophotometric method. In common spectrophotometric method, the calibration curve is A=1.69ρ+0.006 and the correlation coefficient is 0.9994.The apparent molar absorptivity is 5.42×104 L*mol-1*cm-1 and calibration curve is liner when ρ is in the range of 0-0.9 mg*L-1. In total differential spectrophotometric method, the calibration curve is A=9.25ρ+0.004 and the correlation coefficient is 0.9996. The apparent molar absorptivity is 2.96×105 L*mol-1*cm-1and calibration curve is liner when ρ is in the range of 0-0.10 mg*L-1. The sensitivity of this method is increased significantly compared with the former ethylene blue method. The speed of reaction is also faster than the former one. The limit of detection is found to be 1.0 ng*mL-1 by both common spectrophotometric method and total differential spectrophotometric method. Ten replicate analyses of a sample solution containing 100 ng*mL-1sulfide give a relative standard deviation of 1.8%. The effects of various cations and anions on the determination of sulfide are studied and procedures for removal of interference is described. The method is used for the determination of sulfide in environment samples with satisfactory results.

  8. Biogeographic Congruency among Bacterial Communities from Terrestrial Sulfidic Springs

    Directory of Open Access Journals (Sweden)

    Brendan eHeadd

    2014-09-01

    Full Text Available Terrestrial sulfidic springs support diverse microbial communities by serving as stable conduits for geochemically diverse and nutrient-rich subsurface waters. Microorganisms that colonize terrestrial springs likely originate from groundwater, but may also be sourced from the surface. As such, the biogeographic distribution of microbial communities inhabiting sulfidic springs should be controlled by a combination of spring geochemistry and surface and subsurface transport mechanisms, and not necessarily geographic proximity to other springs. We examined the bacterial diversity of seven springs to test the hypothesis that occurrence of taxonomically similar microbes, important to the sulfur cycle, at each spring is controlled by geochemistry. Complementary Sanger sequencing and 454 pyrosequencing of 16S rRNA genes retrieved five proteobacterial classes, and Bacteroidetes, Chlorobi, Chloroflexi, and Firmicutes phyla from all springs, which suggested the potential for a core sulfidic spring microbiome. Among the putative sulfide-oxidizing groups (Epsilonproteobacteria and Gammaproteobacteria, up to 83% of the sequences from geochemically similar springs clustered together. Abundant populations of Hydrogenimonas-like or Sulfurovum-like spp. (Epsilonproteobacteria occurred with abundant Thiothrix and Thiofaba spp. (Gammaproteobacteria, but Arcobacter-like and Sulfurimonas spp. (Epsilonproteobacteria occurred with less abundant gammaproteobacterial populations. These distribution patterns confirmed that geochemistry rather than biogeography regulates bacterial dominance at each spring. Potential biogeographic controls were related to paleogeologic sedimentation patterns that could control long-term microbial transport mechanisms that link surface and subsurface environments. Knowing the composition of a core sulfidic spring microbial community could provide a way to monitor diversity changes if a system is threatened by anthropogenic processes or

  9. Pyrite formation and mineral transformation pathways upon sulfidation of ferric hydroxides depend on mineral type and sulfide concentration

    NARCIS (Netherlands)

    Peiffer, Stefan; Behrends, Thilo; Hellige, Katrin; Larese-Casanova, Philip; Wan, Moli; Pollok, Kilian

    2015-01-01

    The reaction of ferric (hydr)oxides with dissolved sulfide does not lead to the instantaneous production of thermodynamically stable products but can induce a variety of mineral transformations including the formation of metastable intermediates. The importance of the various transformation pathways

  10. Blood Components Prevent Sulfide Poisoning of Respiration of the Hydrothermal Vent Tube Worm Riftia pachyptila

    Science.gov (United States)

    Powell, Mar A.; Somero, George N.

    1983-01-01

    Respiration of plume tissue of the hydrothermal vent tube worm Riftia pachyptila is insensitive to sulfide poisoning in contrast to tissues of animals that do not inhabit vents. Permeability barriers may not be responsible for this insensitivity since plume homogenates are also resistant to sulfide poisoning. Cytochrome c oxidase of plume, however, is strongly inhibited by sulfide at concentrations less than 10 μ M. Factors present in blood, but not in cytosol, prevent sulfide from inhibiting cytochrome c oxidase. Avoidance of sulfide poisoning of respiration in Riftia pachyptila thus appears to involve a blood-borne factor having a higher sulfide affinity than that of cytochrome c oxidase, with the result that appreciable amounts of free sulfide are prevented from accumulating in the blood and entering the intracellular compartment.

  11. Galvanic coupling and its effect on origin potential flotation system of sulfide minerals

    Institute of Scientific and Technical Information of China (English)

    顾帼华; 戴晶平; 王晖; 邱冠周

    2004-01-01

    The galvanic coupling formed in origin potential flotation systems of sulfide minerals can be divided into three types: sulfide mineral-sulfide mineral-water system; sulfide mineral-steel ball-water system; and sulfide mineral-sulfide mineral-collector system. In this paper, taking lead, zinc, iron sulfide mineral systems for examples,several models of galvanic coupling were proposed and the effects of galvanic coupling on flotation were discussed. A galvanic contact between galena (or sphalerite) and pyrite contributes to decreasing the content of zinc in lead concentrate, and enhances remarkably the absorption of collector on the galena surface. During grinding, due to galvanic interactions between minerals and steel medium, Fe(OH)3 formed covers on the cathodic mineral surface, affecting its floatability.

  12. Simulation of sulfide buildup in wastewater and atmosphere of sewer networks.

    Science.gov (United States)

    Nielsen, A H; Yongsiri, C; Hvitved-Jacobsen, T; Vollertsen, J

    2005-01-01

    A model concept for prediction of sulfide buildup in sewer networks is presented. The model concept is an extension to--and a further development of--the WATS model (Wastewater Aerobic-anaerobic Transformations in Sewers), which has been developed by Hvitved-Jacobsen and co-workers at Aalborg University. In addition to the sulfur cycle, the WATS model simulates changes in dissolved oxygen and carbon fractions of different biodegradability. The sulfur cycle was introduced via six processes: 1. sulfide production taking place in the biofilm covering the permanently wetted sewer walls; 2. biological sulfide oxidation in the permanently wetted biofilm; 3. chemical and biological sulfide oxidation in the water phase; 4. sulfide precipitation with metals present in the wastewater; 5. emission of hydrogen sulfide to the sewer atmosphere and 6. adsorption and oxidation of hydrogen sulfide on the moist sewer walls where concrete corrosion may take place.

  13. Conversion kinetics for smelt anions: cyanate and sulfide

    Energy Technology Data Exchange (ETDEWEB)

    DeMartini, N.

    2004-07-01

    Cyanate and sulfide are two anions found in the molten salts (smelt) from the kraft recovery boiler of the chemical recovery cycle. Their concentrations in smelt are significantly different, as are their origins. The concentration of cyanate in smelt ranges between 0.4 and 2.1 g OCN{sup -}/kg smelt while the concentration of sulfide ranges between 78 and 115 g S{sup 2-}/kg smelt. Cyanate is a by-product of black liquor combustion. It is formed from organic nitrogen compounds in black liquor during the char burning stage. The charge of the cyanate anion is balanced by the alkali metals found in smelt, namely sodium and potassium. It has been found that the nitrogen in cyanate represents about 30% of the nitrogen entering the recovery boiler with the black liquor. This flow is similar in magnitude to the flows of black liquor nitrogen exiting the recovery boiler as the gaseous compounds NO and N{sub 2}. The method for cyanate analysis used in this work is presented in the Methods chapter of this thesis and Paper I. The results from nitrogen balances at three European kraft pulp mills are discussed in this thesis and Papers II and III, with a focus on the fate of cyanate in the recovery boiler and recausticizing process. Cyanate exits the recovery boiler with the smelt and reacts to form ammonia in the recausticizing solutions of the chemical recovery cycle. Papers IV and V of this thesis focus on the rate of ammonia formation from cyanate in model solutions and in kraft green liquors. The experiments were carried out at temperatures of 80 to 95 deg C, which are temperatures similar to those found in the recausticizing process of a kraft pulp mill. The kinetic studies help clarify the catalytic effect of bicarbonate. A rate equation applicable for use in describing ammonia formation from cyanate in highly alkaline solutions such as pulp mill recovery streams is presented. The sulfide anion, on the other hand, is a desired product of black liquor combustion as the

  14. Cadmium sulfide and lead sulfide quantum dots in glass: Processing, growth, and optical absorption

    Science.gov (United States)

    Rao, Pratima Gattu Naga

    Glasses containing cadmium sulfide and lead sulfide particles were prepared, and their properties were studied. These particles exhibit quantum confinement behavior when they are smaller than their Bohr exciton radii. Quantum confinement leads to size dependence in the optical absorption of particles. This size dependence can tune the optical absorption of the material to a particular wavelength or energy and possibly enhances the nonlinear optical absorption of the particles. These properties have potential applications in photonic devices. To control the growth of these semiconductor particles in glass, the glass processing conditions were studied. CdS-doped glasses were initially prepared with CdO and ZnS. The sublimation temperature for ZnS is at 1185°C; whereas, CdO sublimes at 1559°C, and CdS at 980°C. Loss of both cadmium and sulfur was observed in open crucible melts, even when CdO and ZnS were used. Improvements in glass processing were made by use of preheat and a cover during the glass melting, resulting in better retention of both dopants. Direct CdS addition to the glasses was possible with these improvements, thus eliminating complications of zinc incorporation during the growth of the semiconductor particles. These methods were successfully applied to the synthesis of PbS-doped glasses. CdS and PbS particles were grown in alkali borosilicate glasses, and their optical absorption spectra were measured as a function of heat treatment temperature and time. The position of the absorption peak and edge shifted to longer wave-lengths, or lower energies, with longer heat treatments at a constant temperature. Both CdS and PbS particles exhibited quantum confinement. These measurements were used to calculate particle sizes from quantum confinement models. Comparisons with transmission electron microscopy (TEM) demonstrated that the 1-term effective-mass approximation was appropriate for estimating CdS particle sizes. A sophisticated four-band envelope

  15. The removal of hydrogen sulfide from gas streams using an aqueous metal sulfate absorbent : Part II. the regeneration of copper sulfide to copper oxide - An experimental study

    NARCIS (Netherlands)

    Ter Maat, H.; Hogendoorn, J. A.; Versteeg, G. F.

    2005-01-01

    Aim of this study was to investigate the possibilities for a selective and efficient method to convert copper(II) sulfide (CuS) into copper(II) oxide (CuO). The oxidation of copper sulfide has been studied experimentally using a thermogravimetric analyzer (TGA) at temperatures ranging from 450 to 75

  16. LUMINESCENCE OF CADMIUM SULFIDE QUANTUM DOTS IN FLUOROPHOSPHATE GLASSES

    Directory of Open Access Journals (Sweden)

    Z. O. Lipatova

    2015-03-01

    Full Text Available Cadmium sulfide quantum dots are perspective materials in optics, medicine, biology and optoelectronics. Fluorophosphate glasses, doped with cadmium sulfide quantum dots, were examined in the paper. Heat treatment led to the formation of quantum dots with diameters equal to 2.8 nm, 3.0 nm and 3.8 nm. In view of such changes in the quantum dots size the fundamental absorption edge shift and the luminescence band are being displaced to the long wavelengths. Luminescence lifetime has been found to be dependent on the registration wavelength in the range from 450 to 700 nm. Obtained fluorophosphate glasses with CdS quantum dots can find their application as fluorescent materials with intensive luminescence band and long excited-state natural lifetime.

  17. Oxygen-free atomic layer deposition of indium sulfide

    Science.gov (United States)

    Martinson, Alex B.; Hock, Adam S.; McCarthy, Robert; Weimer, Matthew S.

    2016-07-05

    A method for synthesizing an In(III) N,N'-diisopropylacetamidinate precursor including cooling a mixture comprised of diisopropylcarbodiimide and diethyl ether to approximately -30.degree. C., adding methyllithium drop-wise into the mixture, allowing the mixture to warm to room temperature, adding indium(III) chloride as a solid to the mixture to produce a white solid, dissolving the white solid in pentane to form a clear and colorless solution, filtering the mixture over a celite plug, and evaporating the solution under reduced pressure to obtain a solid In(III) N,N'-diisopropylacetamidinate precursor. This precursor has been further used to develop a novel atomic layer deposition technique for indium sulfide by dosing a reactor with the precursor, purging with nitrogen, dosing with dilute hydrogen sulfide, purging again with nitrogen, and repeating these steps to increase growth.

  18. L-Cysteine-assisted Synthesis of Copper Gallium Sulfide Microspheres

    Institute of Scientific and Technical Information of China (English)

    LIANG Xiao-juan; ZHONG Jia-song; CAI Qian; HUANG Hai-yu; LIU Hai-tao; XIANG Wei-dong; SUN Jun-cai

    2012-01-01

    An effective L-cysteine-assisted synthetic route has been successfully developed to prepare copper gallium sulfide(CuGaS2) microspheres under solvothermal conditions with CuCI2-2H2O,GaCl3 and L-cysteine as source materials,in which L-cysteine was used as the sulfide source and eomplexing molecule.The experiments revealed that the synthesized sample was of a typical CuGaS2 tetragonal structure.Moreover,the prepared CuGaS2 crystals consisting of microspheres made up of nanoflakes,and the diameter of the nanoflakes was about 20 nm.Raman spectrum of the obtained CuGaS2 exhibits a high-intensity peak of the A1 mode at 306 cm-1.Meanwhile,a possible growth mechanism was proposed based on the investigations.

  19. Fractal characteristics of nanocrystalline indium and gallium sulfide particles

    Energy Technology Data Exchange (ETDEWEB)

    Sastry, P.U., E-mail: psastry@barc.gov.i [Solid State Physics Division, Mumbai 400085 (India); Dutta, Dimple P. [Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)

    2009-11-13

    The structure of nano-sized powders of indium sulfide (In{sub 2}S{sub 3}) and gallium sulfide (Ga{sub 2}S{sub 3}), prepared by single source precursor route has been investigated by small angle X-ray scattering technique. The particle morphology shows interesting fractal nature. For In{sub 2}S{sub 3}, the nanoparticle aggregates show a mass fractal with fractal dimension 2.0 that increases with longer time of thermal treatment. Below the length scale of about 20 nm, the particles have a rough surface with a surface fractal dimension of 2.8. Unlike In{sub 2}S{sub 3}, structure of Ga{sub 2}S{sub 3} exhibits a single surface fractal over whole q-range of study. The estimated particle sizes are in range of 5-15 nm and the results are supported by transmission electron microscope.

  20. 'Low-acid' sulfide oxidation using nitrate-enriched groundwater

    Science.gov (United States)

    Donn, Michael; Boxall, Naomi; Reid, Nathan; Meakin, Rebecca; Gray, David; Kaksonen, Anna; Robson, Thomas; Shiers, Denis

    2016-04-01

    Acid drainage (AMD/ARD) is undoubtedly one of the largest environmental, legislative and economic challenges facing the mining industry. In Australia alone, at least 60m is spent on AMD related issues annually, and the global cost is estimated to be in the order of tens of billions US. Furthermore, the challenge of safely and economically storing or treating sulfidic wastes will likely intensify because of the trend towards larger mines that process increasingly higher volumes of lower grade ores and the associated sulfidic wastes and lower profit margins. While the challenge of managing potentially acid forming (PAF) wastes will likely intensify, the industrial approaches to preventing acid production or ameliorating the effects has stagnated for decades. Conventionally, PAF waste is segregated and encapsulated in non-PAF tips to limit access to atmospheric oxygen. Two key limitations of the 'cap and cover' approach are: 1) the hazard (PAF) is not actually removed; only the pollutant linkage is severed; and, 2) these engineered structures are susceptible to physical failure in short-to-medium term, potentially re-establishing that pollutant linkage. In an effort to address these concerns, CSIRO is investigating a passive, 'low-acid' oxidation mechanism for sulfide treatment, which can potentially produce one quarter as much acidity compared with pyrite oxidation under atmospheric oxygen. This 'low-acid' mechanism relies on nitrate, rather than oxygen, as the primary electron accepter and the activity of specifically cultured chemolithoautotrophic bacteria and archaea communities. This research was prompted by the observation that, in deeply weathered terrains of Australia, shallow (oxic to sub-oxic) groundwater contacting weathering sulfides are commonly inconsistent with the geochemical conditions produced by ARD. One key characteristic of these aquifers is the natural abundance of nitrate on a regional scale, which becomes depleted around the sulfide bodies, and

  1. The bioleaching of different sulfide concentrates using thermophilic bacteria

    Science.gov (United States)

    Torres, F.; Blázquez, M. L.; González, F.; Ballester, A.; Mier, J. L.

    1995-05-01

    The bioleaching of different mineral sulfide concentrates with thermophilic bacteria (genus Sulfolobus @#@) was studied. Since the use of this type of bacteria in leaching systems involves stirring and the control of temperature, the influence of the type of stirring and the pulp density on dissolution rates was studied in order to ascertain the optimum conditions for metal recovery. At low pulp densities, the dissolution kinetic was favored by pneumatic stirring, but for higher pulp densities, orbital stirring produced the best results. A comparative study of three differential concentrates, one mixed concentrate, and one global concentrate was made. Copper and iron extraction is directly influenced by bacterial activity, while zinc dissolution is basically due to an indirect mechanism that is activated in the presence of copper ions. Galvanic interactions between the different sulfides favors the selective bioleaching of some phases (sphalerite and chalcopyrite) and leads to high metal recovery rates. However, the formation of galvanic couples depends on the type of concentrate.

  2. Health assessment document for hydrogen sulfide: review draft

    Energy Technology Data Exchange (ETDEWEB)

    Ammann, H.M.; Bradow, F.; Fennell, D.; Griffin, R.; Kearney, B.

    1986-08-01

    Hydrogen sulfide is a highly toxic gas which is immediately lethal in concentrations greater than 2000 ppm. The toxic end-point is due to anoxia to brain and heart tissues which results from its interaction with the celluar enzyme cytochrome oxidase. Inhibition of the enzyme halts oxidative metabolism which is the primary energy source for cells. A second toxic end-point is the irritative effect of hydrogen sulfide on mucous membranes, particularly edema at sublethal doses (250 to 500 ppm) in which sufficient exposure occurs before conciousness is lost. Recovered victims of exposure report neurologic symptoms such as headache, fatigue, irritability, vertigo, and loss of libido. Long-term effects are similar to those caused by anoxia due to other toxic agents like CO, and probably are not due to specific H/sub 2/S effects. H/sub 2/S is not a cumulative poison. No mutagenic, carcinogenic, reproductive, or teratogenic effects have been reported in the literature.

  3. Synthesis and characterization of cerium sulfide thin film

    Institute of Scientific and Technical Information of China (English)

    Ιshak Afsin Kariper

    2014-01-01

    Cerium sulfide (CexSy) polycrystalline thin film is coated with chemical bath deposition on substrates (commercial glass). Transmittance, absorption, optical band gap and refractive index are examined by using UV/VIS. Spectrum. The hexagonal form is observed in the structural properties in XRD. The structural and optical properties of cerium sulfide thin films are analyzed at different pH. SEM and EDX analyses are made for surface analysis and elemental ratio in films. It is observed that some properties of films changed with different pH values. In this study, the focus is on the observed changes in the properties of films. The pH values were scanned at 6–10. The optical band gap changed with pH between 3.40 to 3.60 eV. In addition, the film thickness changed with pH at 411 nm to 880 nm.

  4. Oxygen-free atomic layer deposition of indium sulfide

    Energy Technology Data Exchange (ETDEWEB)

    Martinson, Alex B.; Hock, Adam S.; McCarthy, Robert; Weimer, Matthew S.

    2016-07-05

    A method for synthesizing an In(III) N,N'-diisopropylacetamidinate precursor including cooling a mixture comprised of diisopropylcarbodiimide and diethyl ether to approximately -30.degree. C., adding methyllithium drop-wise into the mixture, allowing the mixture to warm to room temperature, adding indium(III) chloride as a solid to the mixture to produce a white solid, dissolving the white solid in pentane to form a clear and colorless solution, filtering the mixture over a celite plug, and evaporating the solution under reduced pressure to obtain a solid In(III) N,N'-diisopropylacetamidinate precursor. This precursor has been further used to develop a novel atomic layer deposition technique for indium sulfide by dosing a reactor with the precursor, purging with nitrogen, dosing with dilute hydrogen sulfide, purging again with nitrogen, and repeating these steps to increase growth.

  5. Laboratory SIP signatures associated with oxidation of disseminated metal sulfides

    Science.gov (United States)

    Placencia-Gómez, Edmundo; Slater, Lee; Ntarlagiannis, Dimitrios; Binley, Andrew

    2013-05-01

    Oxidation of metal sulfide minerals is responsible for the generation of acidic waters rich in sulfate and metals. When associated with the oxidation of sulfide ore mine waste deposits the resulting pore water is called acid mine drainage (AMD); AMD is a known environmental problem that affects surface and ground waters. Characterization of oxidation processes in-situ is challenging, particularly at the field scale. Geophysical techniques, spectral induced polarization (SIP) in particular, may provide a means of such investigation. We performed laboratory experiments to assess the sensitivity of the SIP method to the oxidation mechanisms of common sulfide minerals found in mine waste deposits, i.e., pyrite and pyrrhotite, when the primary oxidant agent is dissolved oxygen. We found that SIP parameters, e.g., phase shift, the imaginary component of electrical conductivity and total chargeability, decrease as the time of exposure to oxidation and oxidation degree increase. This observation suggests that dissolution-depletion of the mineral surface reduces the capacitive properties and polarizability of the sulfide minerals. However, small increases in the phase shift and imaginary conductivity do occur during oxidation. These transient increases appear to correlate with increases of soluble oxidizing products, e.g., Fe2 + and Fe3 + in solution; precipitation of secondary minerals and the formation of a passivating layer to oxidation coating the mineral surface may also contribute to these increases. In contrast, the real component of electrical conductivity associated with electrolytic, electronic and interfacial conductance is sensitive to changes in the pore fluid chemistry as a result of the soluble oxidation products released (Fe2 + and Fe3 +), particularly for the case of pyrrhotite minerals.

  6. Aromatic and heterocyclic perfluoroalkyl sulfides. Methods of preparation

    Directory of Open Access Journals (Sweden)

    Vladimir N. Boiko

    2010-08-01

    Full Text Available This review covers all of the common methods for the syntheses of aromatic and heterocyclic perfluoroalkyl sulfides, a class of compounds which is finding increasing application as starting materials for the preparation of agrochemicals, pharmaceutical products and, more generally, fine chemicals. A systematic approach is taken depending on the mode of incorporation of the SRF groups and also on the type of reagents used.

  7. Fabrication and applications of copper sulfide (CuS) nanostructures

    Science.gov (United States)

    Shamraiz, Umair; Hussain, Raja Azadar; Badshah, Amin

    2016-06-01

    This review article presents different fabrication procedures (under the headlines of solvothermal routes, aerosol methods, solution methods and thermolysis), and applications (photocatalytic degradation, ablation of cancer cells, electrode material in lithium ion batteries and in gas sensing, organic solar cells, field emission properties, super capacitor applications, photoelectrochemical performance of QDSCs, photocatalytic reduction of organic pollutants, electrochemical bio sensing, enhanced PEC characteristics of pre-annealed CuS film electrodes) of copper sulfide (Covellite).

  8. Formation of iron sulfide nodules during anaerobic oxidation

    OpenAIRE

    van Dongen, B. E.; Organic Geochemistry Unit, Bristol Biogeochemistry Research Centre, School of Chemistry, Cantock’s Close, Bristol University, Bristol BS8 1TS, United Kingdom; Roberts, A. P.; National Oceanography Centre, University of Southampton, Southampton, UK.; Schouten, S.; Department of Marine Biogeochemistry, Royal Netherlands Institute for Sea Research, P.O. Box 59, 1790 AB Den Burg, Texel, The Netherlands; Jiang, W-T; Department of Earth Sciences, National Cheng Kung University, Tainan 70101, Taiwan, PR China; Florindo, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Pancost, R. D.; Organic Geochemistry Unit, Bristol Biogeochemistry Research Centre, School of Chemistry, Cantock’s Close, Bristol University, Bristol BS8 1TS, United Kingdom

    2007-01-01

    The biomarker compositions of iron sulfide nodules (ISNs; upper Pliocene Valle Ricca section near Rome, Italy) that contain the ferrimagnetic mineral greigite (Fe3S4) were examined. In addition to the presence of specific terrestrial and marine biomarkers, consistent with formation in coastal marine sediments, these ISNs contain compounds thought to originate from sulfate reducing bacteria (SRB). These compounds include a variety of low-molecular-weight and branched alkanols and seve...

  9. Discrimination among iron sulfide species formed in microbial cultures.

    Science.gov (United States)

    Popa, R; Kinkle, B K

    2000-10-01

    A quantitative method for the study of iron sulfides precipitated in liquid cultures of bacteria is described. This method can be used to quantify and discriminate among amorphous iron sulfide (FeS(amorph)), iron monosulfide minerals such as mackinawite or greigite (FeS(min)), and iron disulfide minerals such as pyrite or marcasite (FeS(2min)) formed in liquid cultures. Degradation of iron sulfides is performed using a modified Cr(2+) reduction method with reflux distillation. The basic steps of the method are: first, separation of FeS(amorph); second, elimination of interfering species of S such as colloidal sulfur (S(c) degrees ), thiosulphate (S(2)O(3)(2-)) and polysulfides (S(x)(2-)); third, separation of FeS(min); and fourth, separation of FeS(2min). The final product is H(2)S which is determined after trapping. The efficiency of recovery is 96-99% for FeS(amorph), 76-88% for FeS(min), and >97% for FeS(2min). This method has a high reproducibility if the experimental conditions are rigorously applied and only glass conduits are used. A well ventilated fume hood must be used because of the toxicity and volatility of several reagents and products. The advantage relative to previously described methods are better resolution for iron sulfide species and use of the same bottles for both incubation of cultures and acid degradation. The method can also be used for Fe/S stoichiometry with sub-sampling and Fe analysis. PMID:11018273

  10. Delivering carbide ligands to sulfide-rich clusters.

    Science.gov (United States)

    Reinholdt, Anders; Herbst, Konrad; Bendix, Jesper

    2016-02-01

    The propensity of the terminal ruthenium carbide Ru(C)Cl2(PCy3)2 (RuC) to form carbide bridges to electron-rich transition metals enables synthetic routes to metal clusters with coexisting carbide and sulfide ligands. Electrochemical experiments show the Ru≡C ligand to exert a relatively large electron-withdrawing effect compared with PPh3, effectively shifting redox potentials.

  11. Selective Facet Reactivity During Cation Exchange in Cadmium Sulfide Nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Sadtler, Bryce; Demchenko, Denis; Zheng, Haimei; Hughes, Steven; Merkle, Maxwell; Dahmen, Ulrich; Wang, Lin-Wang; Alivisatos, A. Paul

    2008-12-18

    The partial transformation of ionic nanocrystals through cation exchange has been used to synthesize nanocrystal heterostructures. We demonstrate that the selectivity for cation exchange to take place at different facets of the nanocrystal plays an important role in determining the resulting morphology of the binary heterostructure. In the case of copper I (Cu+) cation exchange in cadmium sulfide (CdS) nanorods, the reaction starts preferentially at the ends of the nanorods such that copper sulfide (Cu2S) grows inwards from either end. The resulting morphology is very different from the striped pattern obtained in our previous studies of silver I (Ag+) exchange in CdS nanorods where non-selective nucleation of silver sulfide (Ag2S) occurs. From interface formation energies calculated for several models of epitaxialconnections between CdS and Cu2S or Ag2S, we infer the relative stability of each interface during the nucleation and growth of Cu2S or Ag2S within the CdS nanorods. The epitaxial connections of Cu2S to the end facets of CdS nanorods minimize the formation energy, making these interfaces stable throughout the exchange reaction. However, as the two end facets of wurtzite CdS nanorods are crystallographically nonequivalent, asymmetric heterostructures can be produced.

  12. Sulfide Capacity in Ladle Slag at Steelmaking Temperatures

    Science.gov (United States)

    Allertz, Carl; Sichen, Du

    2015-12-01

    Sulfide capacity measurements were conducted at 1823 K and 1873 K (1550 °C and 1600 °C) for the quaternary Al2O3-CaO-MgO-SiO2 system, for typical compositions used in the ladle in steelmaking. A copper-slag equilibrium was used under controlled oxygen and sulfur potentials. The sulfide capacity is strongly dependent on the composition and it was found to increase with the basic oxides, while it decreases with increase of the acidic components. It was found that CaO is more effective in holding sulfur in the slag compared to MgO when replacing SiO2. For the present slag compositions, Al2O3 and SiO2 behaved similar with respect to sulfur, and no considerable effect could be recorded when replacing one for the other. The sulfide capacity was also found to be strongly dependent on the temperature, increasing with temperature. The present results were compared with industrial data from the ladle, after vacuum treatment, and they were in good agreement.

  13. [The balneotherapeutic components of sulfide-containing mineral waters].

    Science.gov (United States)

    Khutoryansky, V A; Gorshkov, A G

    2015-01-01

    It has been suggested in an early study that sulfanes may serve as a source of sulfur contained in hydrogen sulfide sources. We have performed derivatization of sulfanes, known to be present in the "Novonukutskaya" mineral water. The presence of polysulfanes in balneotherapeutic sulfide waters was confirmed by the HPLC-UV and chromato-mass spectrometric techniques. Derivatization of inorganic polysulfides was achieved by using the reaction with methyl iodide. It was shown that polysulfanes contained in the examined samples were metastable and disintegrated into So and H2S. Almost all molecular zero-valent sulfur was present in the form of S8. The application of HPLC allowed to determine the equilibrium concentration of molecular sulfur. The presence of the above compounds in therapeutic sulfide waters raises the question of the mechanism of their curative action. The authors hypothesize that it may be related to the high therapeutic potency of the substances obtained by steam distillation from the "Novonukutskaya" mineral water. PMID:26841531

  14. The Role of Hydrogen Sulfide in Evolution and the Evolution of Hydrogen Sulfide in Metabolism and Signaling.

    Science.gov (United States)

    Olson, Kenneth R; Straub, Karl D

    2016-01-01

    The chemical versatility of sulfur and its abundance in the prebiotic Earth as reduced sulfide (H2S) implicate this molecule in the origin of life 3.8 billion years ago and also as a major source of energy in the first seven-eighths of evolution. The tremendous increase in ambient oxygen ∼ 600 million years ago brought an end to H2S as an energy source, and H2S-dependent animals either became extinct, retreated to isolated sulfide niches, or adapted. The first 3 billion years of molecular tinkering were not lost, however, and much of this biochemical armamentarium easily adapted to an oxic environment where it contributes to metabolism and signaling even in humans. This review examines the role of H2S in evolution and the evolution of H2S metabolism and signaling. PMID:26674552

  15. A recovery installation for sodium sulfates, thiosulfates and sulfides from waste water resulting from hydrogen sulfide fabrication

    International Nuclear Information System (INIS)

    An installation for recovery of sodium sulfate and sulfur suspensions from waste water was conceived. It consists from a preheater, vacuum evaporator and a refrigerating system with drum and scraper. This equipment concentration the solution by eliminating in the first stage the water in the vacuum evaporator. The water resulting at this stage is chemically pure and can be discharged in the sewage sludge system. The concentrated solution is then directed to the refrigerating system with drum and scrapper. Here the sodium sulfates, thiosulfates and sulfides get crystallized onto the drum surface. The resulting aqueous solution to be discharged in the sewage sludge system is previously analyzed as in case of the absent of the recovery installation, but the amount of pollutants will be much lower because sulfates, thiosulfates and sulfides were already recovered as scales from the drum. These solid scales can be used in detergent industry

  16. Influence of sulfide concentration on the corrosion behavior of pure copper in synthetic seawater

    Science.gov (United States)

    Taniguchi, Naoki; Kawasaki, Manabu

    2008-09-01

    Corrosion rate and stress corrosion cracking (SCC) behavior of pure copper under anaerobic conditions were studied by immersion tests and slow strain rate tests (SSRT) in synthetic seawater containing Na 2S. The corrosion rate was increased with sulfide concentration both in simple saline solution and in bentnite-sand mixture. The results of SSRT showed that copper was susceptible to intergranular attack; selective dissolution at lower sulfide concentration (less than 0.005 M) and SCC at higher sulfide concentration (0.01 M). It was expected that if the sulfide concentration in groundwater is less than 0.001 M, pure copper is possible to exhibit superior corrosion resistance under anaerobic condition evident by very low corrosion rates and immunity to SCC. In such a low sulfide environment, copper overpack has the potential to achieve super-long lifetimes exceeding several tens of thousands years according to long-term simulations of corrosion based on diffusion of sulfide in buffer material.

  17. Regulation of bacterial sulfate reduction and hydrogen sulfide fluxes in the central Namibian coastal upwelling zone

    DEFF Research Database (Denmark)

    Bruchert, V.; Jørgensen, BB; Neumann, K.;

    2003-01-01

    and the low capacity to oxidize and trap sulfide. The inner shelf break marks the seaward border of sulfidic bottom waters, and separates two different regimes of bacterial sulfate reduction. In the sulfidic bottom waters on the shelf, up to 55% of sulfide oxidation is mediated by the large nitrate......The coastal upwelling system off central Namibia is one of the most productive regions of the oceans and is characterized by frequently occurring shelf anoxia with severe effects for the benthic life and fisheries. We present data on water column dissolved oxygen, sulfide, nitrate and nitrite, pore...... water profiles for dissolved,sulfide and sulfate, S-35-sulfate reduction rates, as well as bacterial counts of large sulfur bacteria from 20 stations across the continental shelf and slope. The stations covered two transects and included the inner shelf with its anoxic and extremely oxygen...

  18. When can Electrochemical Techniques give Reliable Corrosion Rates on Carbon Steel in Sulfide Media?

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel; Hemmingsen, Tor; Nielsen, Lars Vendelbo;

    2005-01-01

    Effects of film formation on carbon steel in hydrogen sulfide media may corrupt corrosion rate monitoring by electrochemical techniques. Electrochemical data from hydrogen sulfide solutions, biological sulfide media and natural sulfide containing geothermal water have been collected and the process...... of film formation in sulfide solutions was followed by video. It can be shown that capacitative and diffusional effects due to porous reactive deposits tend to dominate the data resulting in unreliable corrosion rates measured by electrochemical techniques. The effect is strongly increased if biofilm...... in combination with ferrous sulfide corrosion products cover the steel surface. Corrosion rates can be overestimated by a factor of 10 to 100 with electrochemical techniques - both by linear polarization resistance (LPR) and electrochemical impedance spectroscopy (EIS). Oxygen entering the system accelerates...

  19. Modeling of hydrogen sulfide oxidation in concrete corrosion products from sewer pipes.

    Science.gov (United States)

    Jensen, Henriette Stokbro; Nielsen, Asbjørn Haaning; Hvitved-Jacobsen, Thorkild; Vollertsen, Jes

    2009-04-01

    Abiotic and biotic oxidation of hydrogen sulfide related to concrete corrosion was studied in corrosion products originating from a sewer manhole. The concrete corrosion products were suspended in an acidic solution, mimicking the conditions in the pore water of corroded concrete. The removal of hydrogen sulfide and dissolved oxygen was measured in parallel in the suspension, upon which the suspension was sterilized and the measurement repeated. The results revealed the biotic oxidation to be fast compared with the abiotic oxidation. The stoichiometry of the hydrogen sulfide oxidation was evaluated using the ratio between oxygen and hydrogen sulfide uptake. The ratio for the biotic oxidation pointed in the direction of elemental sulfur being formed as an intermediate in the oxidation of hydrogen sulfide to sulfuric acid. The experimental results were applied to suggest a hypothesis and a mathematical model describing the hydrogen sulfide oxidation pathway in a matrix of corroded concrete.

  20. Microbial control of the production of hydrogen sulfide by sulfate-reducing bacteria.

    Science.gov (United States)

    Montgomery, A D; McLnerney, M J; Sublette, K L

    1990-03-01

    A sulfide-resistant ctrain of Thiobacillus denitrificans, strain F, prevented the accumulation of sulfide by Desulfovibrio desulfuricans when both organisms were grown in liquid medium or in Berea sandstone cores. The wild-type strain of T. denitrificans did not prevent the accumulation of sulfide produced by D. desulfuricans. Strain F also prevented the accumulation of sulfide by a mixed population of sulfate-reducing bacteria enriched from an oil field brine. Fermentation balances showed that strain F stoichiometrically oxidized the sulfide produced by D. desulfuricans and the oil field brine enrichment to sulfate. These data suggest that strain F would be effective in controlling sulfide production in oil reservoirs and other environments.

  1. Inhibition of Sulfide Mineral Oxidation by Surface Coating Agents: Batch

    Science.gov (United States)

    Choi, J.; Ji, M. K.; Yun, H. S.; Park, Y. T.; Gee, E. D.; Lee, W. R.; Jeon, B.-H.

    2012-04-01

    Mining activities and mineral industries have impacted on rapid oxidation of sulfide minerals such as pyrite (FeS2) which leads to Acid Mine Drainage (AMD) formation. Some of the abandoned mines discharge polluted water without proper environmental remediation treatments, largely because of financial constraints in treating AMD. Magnitude of the problem is considerable, especially in countries with a long history of mining. As metal sulfides become oxidized during mining activities, the aqueous environment becomes acid and rich in many metals, including iron, lead, mercury, arsenic and many others. The toxic heavy metals are responsible for the environmental deterioration of stream, groundwater and soils. Several strategies to remediate AMD contaminated sites have been proposed. Among the source inhibition and prevention technologies, microencapsulation (coating) has been considered as a promising technology. The encapsulation is based on inhibition of O2 diffusion by surface coating agent and is expected to control the oxidation of pyrite for a long time. Potential of several surface coating agents for preventing oxidation of metal sulfide minerals from both Young-Dong coal mine and Il-Gwang gold mine were examined by conducting batch experiments and field tests. Powdered pyrite as a standard sulfide mineral and rock samples from two mine outcrops were mixed with six coating agents (KH2PO4, MgO and KMnO4 as chemical agents, and apatite, cement and manganite as mineral agents) and incubated with oxidizing agents (H2O2 or NaClO). Batch experiments with Young-Dong coal mine samples showed least SO42- production in presence of KMnO4 (16% sulfate production compared to no surface coating agents) or cement (4%) within 8 days. In the case of Il-Gwang mine samples, least SO42- production was observed in presence of KH2PO4 (8%) or cement (2%) within 8 days. Field-scale pilot tests at Il-Gwang site also showed that addition of KH2PO4 decreased sulfate production from 200 to

  2. Synthesis, characterization, and reactivity of sulfided hexanuclear molybdenum cluster compounds

    Energy Technology Data Exchange (ETDEWEB)

    Spink, D.

    1990-09-21

    Hexanuclear molybdenum clusters with mixed chloride and sulfide bridging ligands were prepared by reacting {alpha}-MoCl{sub 2} with sodium hydrosulfide in the presence of sodium butoxide. The resulting species, Mo{sub 6}Cl{sub (8-x)}S{sub x}{center dot}npy(x {congruent} 3.6, n {congruent} 4, py = pyridine), was pyrophoric and insoluble. The mixed sulfide chloride cluster species Mo{sub 6}S{sub 4}Cl{sub 4}{center dot}6OPEt{sub 3} and Mo{sub 6}S{sub {approximately}5}Cl{sub {approximately}3}{center dot}6PEt{sub 3} and Mo{sub 6}S{sub 8}{center dot}6PEt{sub 3} were isolated and characterized. Phosphorus-31 nuclear magnetic resonance, electron paramagnetic resonance, and UV/visible spectra were obtained for each fraction. The completely sulfided cluster, Mo{sub 6}S{sub 8}{center dot}6PEt{sub 3}, was prepared similarly and used in various experiments as a possible precursor to Chevrel phase materials of the type Mo{sub 6}S{sub 8}or M{sub n}Mo{sub 6}S{sub 8}. With the goal of removing all of the triethylphosphine ligands, Mo{sub 6}S{sub 8}{center dot}6PEt{sub 3} was reacted with the transition metal carbonyls molybdenum hexacarbonyl and dicobalt octacarbonyl. Reaction on the molecular sulfide cluster with copper(I) chloride in toluene gave a completely insoluble product. The reaction of Mo{sub 6}S{sub 8}{center dot}6PEt{sub 3} with propylene sulfide gave a product whose infrared spectra showed only very weak peaks associated with coordinated triethylphosphine. The elemental analysis of this product fit the formula Mo{sub 6}S{sub 8}{center dot}5SPEt{sub 3}. Reactivity of the outer ligands of the Mo{sub 6}S{sub 8}{center dot}npy and Mo{sub 6}S{sub 8}{center dot}(6{minus}x)PrNH{sub x} clusters were investigated. Crystalline Mo{sub 6}S{sub 8}{center dot}6THT was recovered from the reaction of the n-propylamine derivative with THT. A crystal structure determination was done. 87 refs., 12 fig., 15 tabs.

  3. Silicate sulfidation and chemical differences between enstatite chondrites and Earth

    Science.gov (United States)

    Lehner, S. W.; Petaev, M. I.; Buseck, P. R.

    2013-12-01

    Isotopic similarity between the Earth-Moon system and enstatite chondrites (ECs) led to the idea that ECs were Earth's building blocks [1-3]. However, compared to Earth's mantle, ECs have low Fe0/Fe ratios, are enriched in volatile elements, and depleted in refractory lithophile elements and Mg [4]. Therefore, deriving Earth composition from ECs requires a loss of volatiles during or prior to accretion and sequestering a large fraction of Si in the deep Earth. Alternatively, the isotopic similarity between the Earth and ECs is explained by their formation from a common precursor that experienced different evolutionary paths resulting in the chemical difference [4]. The vestiges of such a precursor are still present in the unequilibrated ECs as FeO-rich silicates with O isotopic compositions identical to bulk ECs and Earth [5]. Conversion of such a precursor into the characteristic EC mineral assemblage requires high-temperature processing in an H-poor environment with high fS2 and fO2 close to that of the classic solar nebula [6], consistent with redox conditions inferred from Ti4+/Ti3+ ratios in EC pyroxene [7]. Under such conditions reaction of FeO-rich silicates with S-rich gas results in their replacement by the assemblage of FeO-poor silicates; Fe, Mg, Ca sulfides; free silica; and Si-bearing Fe,Ni metal alloy. The progressive sulfidation of ferromagnesian silicates in chondrules results in loss of Mg and addition of Fe, Mn, S, Na, K and, perhaps, other volatiles [6]. At the advanced stages of silicate sulfidation recorded in the metal-sulfide nodules [8], a portion of Si is reduced and dissolved in the Fe,Ni metal. This process is known to fractionate Si isotopes [9,10] and would explain the differences between the ECs and Earth's mantle [11]. The sulfidation of silicates also produces porous S-rich silica, a peculiar phase observed so far only in the ECs. It consists of a sinewy SiO2-rich framework enclosing numerous vesicles filled with beam

  4. Antifoaming materials in G.S. (Girlder sulfide) heavy water plants. Thermical stability. Pt. 2

    International Nuclear Information System (INIS)

    In Girlder sulfide (G.S.) heavy water plants hydrogen sulfide-water systems are inherentely foaming, so the adding of antifoaming materials is of great importance. These may be of high volatility, pyrolizable or chemically unstable in plant operation conditions (water and hydrogen sulfide at 2 MPa, up to 230 deg C). About twenty commercial surfactants were studied from the point of view of their thermical stability. (Author)

  5. Research of the Plasma Sulfide Layer Formed on the Nitrocarburizing Layer

    Institute of Scientific and Technical Information of China (English)

    LI Xin; MA Shi-ning; HU Chun-hua; QIU Ji; HUANG Yuan-lin

    2004-01-01

    Low-temperature sulfurizing after nitrocarburizing are compared with only low-temperature sulfurizing on the surface of CrMoCu alloyed cast iron, the surface morphologies and microstructures are investigated by SEM and EDS.Results show that under proper treatment parameters, there are sulfide layer on both of the surfaces, and can more easily obtain sulfide layers on the surface of nitrocarburizing. Forming mechanism of sulfides were also studied elementarily.

  6. High Temperature Corrosion of Fe-C-S Cast Irons in Oxidizing and Sulfidizing Atmospheres

    Institute of Scientific and Technical Information of China (English)

    Thuan-Dinh NGUYEN; Dong-Bok LEE

    2008-01-01

    The corrosion behavior of spheroidal graphite and flake graphite cast irons was studied in oxidizing and sulfidizing atmospheres between 600 and 800℃ for 50 h. The corrosion rate in the sulfidizing atmosphere was faster than that in air above 700℃, due to the formation of the Feo.975S sulfide. The corrosion rate of the spheroidal graphite cast iron was similar to that of the flake graphite cast iron.

  7. Regarding "Sulfide Capacity in Ladle Slag at Steelmaking Temperatures," C. Allertz, Du Sichen; MMTB 2015 December

    Science.gov (United States)

    Pelton, Arthur; Kang, Youn-Bae

    2016-09-01

    Allertz and Sichen measured sulfide contents of slags in equilibrium with Cu-S solutions. Results are in very good agreement with calculations by FactSage whose databases were developed by modeling other sets of data obtained under different conditions. However, when results are reported as sulfide capacities, significant errors may result if these are used to calculate sulfide contents at oxygen and sulfur potentials which differ from those of the experiments and/or are fixed by different means.

  8. 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...

  9. Biogenic hydrogen sulfide in the oil gas of Western Siberian fields

    Energy Technology Data Exchange (ETDEWEB)

    Yershov, V.A.; Chetverkina, V.N.; Nosova, V.S.; Shakirova, A.Kh.

    1984-01-01

    In connection with the discovery of biogenic hydrogen sulfide in the oil gas of Western Siberian fields, the quantity of hydrogen sulfide has been monitored and the dynamics of the development of the sulfate reduction processes and their features are examined. It is noted that in the absence of influences on the bacterial flora, it is necessary to eliminate hydrogen sulfide from natural gas or to use hydrogen sulfide corrosion inhibiters in order to suppress biocenosis in building gas processing plants and gas lift systems, in order to reduce equipment corrosion.

  10. Microbial oxidation of soluble sulfide in produced water from the Bakkeen Sands

    Energy Technology Data Exchange (ETDEWEB)

    Gevertz, D.; Zimmerman, S. [Agouron Institute, La Jolla, CA (United States); Jenneman, G.E. [Phillips Petroleum Company, Bartlesville, OK (United States)] [and others

    1995-12-31

    The presence of soluble sulfide in produced water results in problems for the petroleum industry due to its toxicity, odor, corrosive nature, and potential for wellbore plugging. Sulfide oxidation by indigenous nitrate-reducing bacteria (NRB) present in brine collected from wells at the Coleville Unit (CVU) in Saskatchewan, Canada, was investigated. Sulfide oxidation took place readily when nitrate and phosphate were added to brine enrichment cultures, resulting in a decrease in sulfide levels of 99-165 ppm to nondetectable levels (< 3.3 ppm). Produced water collected from a number of producing wells was screened to determine the time required for complete sulfide oxidation, in order to select candidate wells for treatment. Three wells were chosen, based on sulfide removal in 48 hours or less. These wells were treated down the backside of the annulus with a solution containing 10 mM KNO{sub 3} and 100 {mu}M NaH{sub 2}PO{sub 4}. Following a 24- to 72-hour shut-in, reductions in pretreatment sulfide levels of greater than 90% were observed for two of the wells, as well as sustained sulfide reductions of 50% for at least two days following startup. NRB populations in the produced brine were observed to increase significantly following treatment, but no significant increases in sulfate-reducing bacteria were observed. These results demonstrate the technical feasibility of stimulating indigenous populations of NRB to remediate and control sulfide in produced brine.

  11. Spectral induced polarization and electrodic potential monitoring of microbially mediated iron sulfide transformations

    Energy Technology Data Exchange (ETDEWEB)

    Hubbard, Susan; Personna, Y.R.; Ntarlagiannis, D.; Slater, L.; Yee, N.; O' Brien, M.; Hubbard, S.

    2008-02-15

    Stimulated sulfate-reduction is a bioremediation technique utilized for the sequestration of heavy metals in the subsurface.We performed laboratory column experiments to investigate the geoelectrical response of iron sulfide transformations by Desulfo vibriovulgaris. Two geoelectrical methods, (1) spectral induced polarization (SIP), and (2) electrodic potential measurements, were investigated. Aqueous geochemistry (sulfate, lactate, sulfide, and acetate), observations of precipitates (identified from electron microscopy as iron sulfide), and electrodic potentials on bisulfide ion (HS) sensitive silver-silver chloride (Ag-AgCl) electrodes (630 mV) were diagnostic of induced transitions between an aerobic iron sulfide forming conditions and aerobic conditions promoting iron sulfide dissolution. The SIP data showed 10m rad anomalies during iron sulfide mineralization accompanying microbial activity under an anaerobic transition. These anomalies disappeared during iron sulfide dissolution under the subsequent aerobic transition. SIP model parameters based on a Cole-Cole relaxation model of the polarization at the mineral-fluid interface were converted to (1) estimated biomineral surface area to pore volume (Sp), and (2) an equivalent polarizable sphere diameter (d) controlling the relaxation time. The temporal variation in these model parameters is consistent with filling and emptying of pores by iron sulfide biofilms, as the system transitions between anaerobic (pore filling) and aerobic (pore emptying) conditions. The results suggest that combined SIP and electrodic potential measurements might be used to monitor spatiotemporal variability in microbial iron sulfide transformations in the field.

  12. Formation of Iron Sulfide in Water-Body Sediment and Its Influence on Environment

    Institute of Scientific and Technical Information of China (English)

    YAN Lei; SUMI Katsuhiro

    2008-01-01

    Iron sulfide is an important reductive pollutant in aquatic sediment, so that increasing attentions have been paid to it in recent years. In this paper, the formation of iron sulfide in water-body sediment was introduced. Moreover, its adverse influences upon environment were summarized, including direct contribution to deficiency of dissolved oxygen in water, association with eutrophication in water-bodies and impact on geochemical sulfur cycle. Since conventional chemical analysis for iron sulfide has several disadvantages, new technique for rapid determination of iron sulfide on-line was prospected.

  13. The Terminal Oxidase Cytochrome bd Promotes Sulfide-resistant Bacterial Respiration and Growth.

    Science.gov (United States)

    Forte, Elena; Borisov, Vitaliy B; Falabella, Micol; Colaço, Henrique G; Tinajero-Trejo, Mariana; Poole, Robert K; Vicente, João B; Sarti, Paolo; Giuffrè, Alessandro

    2016-01-01

    Hydrogen sulfide (H2S) impairs mitochondrial respiration by potently inhibiting the heme-copper cytochrome c oxidase. Since many prokaryotes, including Escherichia (E.) coli, generate H2S and encounter high H2S levels particularly in the human gut, herein we tested whether bacteria can sustain sulfide-resistant O2-dependent respiration. E. coli has three respiratory oxidases, the cyanide-sensitive heme-copper bo3 enzyme and two bd oxidases much less sensitive to cyanide. Working on the isolated enzymes, we found that, whereas the bo3 oxidase is inhibited by sulfide with half-maximal inhibitory concentration IC50 = 1.1 ± 0.1 μM, under identical experimental conditions both bd oxidases are insensitive to sulfide up to 58 μM. In E. coli respiratory mutants, both O2-consumption and aerobic growth proved to be severely impaired by sulfide when respiration was sustained by the bo3 oxidase alone, but unaffected by ≤200 μM sulfide when either bd enzyme acted as the only terminal oxidase. Accordingly, wild-type E. coli showed sulfide-insensitive respiration and growth under conditions favouring the expression of bd oxidases. In all tested conditions, cyanide mimicked the functional effect of sulfide on bacterial respiration. We conclude that bd oxidases promote sulfide-resistant O2-consumption and growth in E. coli and possibly other bacteria. The impact of this discovery is discussed. PMID:27030302

  14. XAFS characterization of industrial catalysts: in situ study of phase transformation of nickel sulfide

    Science.gov (United States)

    Wang, J.; Jia, Z.; Wang, Q.; Zhao, S.; Xu, Z.; Yang, W.; Frenkel, A. I.

    2016-05-01

    The online sulfiding process for nickel-contained catalyst often ends up with a nickel sulfide mixture in refinery plant. To elucidate the local environment of nickel and its corresponding sulfur species, a model catalyst (nickel sulfide) and model thermal process were employed to explore the possibilities for characterization of real catalysts in industrial conditions. The present investigation shows effectiveness of in situ XANES and EXAFS measurements for studying the phase stability and phase composition in these systems, which could be used to simulate real sulfiding process in industrial reactions, such as hydrodesulfurizations of oil.

  15. Enhanced performance of denitrifying sulfide removal process under micro-aerobic condition

    International Nuclear Information System (INIS)

    The denitrifying sulfide removal (DSR) process with bio-granules comprising both heterotrophic and autotrophic denitrifiers can simultaneously convert nitrate, sulfide and acetate into di-nitrogen gas, elementary sulfur and carbon dioxide, respectively, at high loading rates. This study determines the reaction rate of sulfide oxidized into sulfur, as well as the reduction of nitrate to nitrite, would be enhanced under a micro-aerobic condition. The presence of limited oxygen mitigated the inhibition effects of sulfide on denitrifier activities, and enhanced the performance of DSR granules. The advantages and disadvantages of applying the micro-aerobic condition to the DSR process are discussed.

  16. Sulfur speciation and sulfide oxidation in the water column of the Black Sea

    Science.gov (United States)

    Luther, George W., III; Church, Thomas M.; Powell, David

    We have applied sulfur speciation techniques to understand the chemistry and cycling of sulfur in Black Sea waters. The only reduced dissolved inorganic sulfur species detected (above the low minimum detection limits of the voltammetric methods employed) in the water column was hydrogen sulfide. The maximum concentration of sulfide (423 μM) is similar to previous reports. Using a cathodic stripping square wave voltammetry (CSSWV) method for nanomolar levels of sulfide, we determined the precise boundary between the "free" hydrogen sulfide (sulfidic) zone and the upper (oxic/suboxic) water column at the two stations studied. This boundary has apparently moved up by about 50 m in the past 20 years. Our results help demonstrate three chemically distinct zones of water in the central basin of the Black Sea: (1) the oxic [0-65 m], (2) the anoxic/nonsulfidic [65-100 m] and (3) the sulfidic [>100 m]. Sulfide bound to metals ("complexed" sulfide) is observed in both the oxic and anoxic/nonsulfidic zones of the water column. This supports previous studies on metal sulfide forms. From the electrochemical data, it is possible to estimate the strength of the complexation of sulfide to metals (log K = 10 to 11). Thiosulfate and sulfite were below our minimum detectable limit (MDL) of 50 nM using CSSWV. Elemental sulfur (MDL 5 nM) was detected below the onset of the hydrogen sulfide zone (90-100 m) with a maximum of 30-60 nM near 120 m. The sulfur speciation results for the Black Sea are lower by one order of magnitude or more than other marine systems such as the Cariaco Trench and salt marshes. New HPLC techniques were applied to detect thiols at submicromolar levels. The presence of thiols (2-mercaptoethylamine, 2-mercaptoethanol, N-acetylcysteine and glutathione) is correlated with the remineralization of organic matter at the oxic and anoxic/nonsulfidic interface. Water samples collected from the upper 50 m of the sulfidic zone showed significant sulfide oxidation on

  17. Pd-NHC-Catalyzed Alkynylation of General Aryl Sulfides with Alkynyl Grignard Reagents.

    Science.gov (United States)

    Baralle, Alexandre; Yorimitsu, Hideki; Osuka, Atsuhiro

    2016-07-25

    Cross-coupling reactions of unactivated aryl sulfides with alkynylmagnesium chloride have been invented to afford 1-aryl-1-alkynes with the aid of a palladium/N-heterocyclic carbene complex. This reaction has by far the widest scope of all transformations utilizing aryl sulfides and alkynes, while known cross-coupling alkynylations of aryl-sulfur electrophiles require activated azaaryl sulfides, thiolactams, or arenesulfonyl chlorides. The alkynylation of aryl sulfides is compatible with typical protecting functional groups. The alkynylation is applied to the synthesis of benzofuran-based fluorescent molecules by taking advantage of characteristic organosulfur chemistry.

  18. In Situ Gene Expression Responsible for Sulfide Oxidation and CO2 Fixation of an Uncultured Large Sausage-Shaped Aquificae Bacterium in a Sulfidic Hot Spring.

    Science.gov (United States)

    Tamazawa, Satoshi; Yamamoto, Kyosuke; Takasaki, Kazuto; Mitani, Yasuo; Hanada, Satoshi; Kamagata, Yoichi; Tamaki, Hideyuki

    2016-06-25

    We investigated the in situ gene expression profile of sulfur-turf microbial mats dominated by an uncultured large sausage-shaped Aquificae bacterium, a key metabolic player in sulfur-turfs in sulfidic hot springs. A reverse transcription-PCR analysis revealed that the genes responsible for sulfide, sulfite, and thiosulfate oxidation and carbon fixation via the reductive TCA cycle were continuously expressed in sulfur-turf mats taken at different sampling points, seasons, and years. These results suggest that the uncultured large sausage-shaped bacterium has the ability to grow chemolithoautotrophically and plays key roles as a primary producer in the sulfidic hot spring ecosystem in situ.

  19. In Situ Gene Expression Responsible for Sulfide Oxidation and CO2 Fixation of an Uncultured Large Sausage-Shaped Aquificae Bacterium in a Sulfidic Hot Spring.

    Science.gov (United States)

    Tamazawa, Satoshi; Yamamoto, Kyosuke; Takasaki, Kazuto; Mitani, Yasuo; Hanada, Satoshi; Kamagata, Yoichi; Tamaki, Hideyuki

    2016-06-25

    We investigated the in situ gene expression profile of sulfur-turf microbial mats dominated by an uncultured large sausage-shaped Aquificae bacterium, a key metabolic player in sulfur-turfs in sulfidic hot springs. A reverse transcription-PCR analysis revealed that the genes responsible for sulfide, sulfite, and thiosulfate oxidation and carbon fixation via the reductive TCA cycle were continuously expressed in sulfur-turf mats taken at different sampling points, seasons, and years. These results suggest that the uncultured large sausage-shaped bacterium has the ability to grow chemolithoautotrophically and plays key roles as a primary producer in the sulfidic hot spring ecosystem in situ. PMID:27297893

  20. Sulfide-driven arsenic mobilization from arsenopyrite and black shale pyrite

    Science.gov (United States)

    Zhu, W.; Young, L.Y.; Yee, N.; Serfes, M.; Rhine, E.D.; Reinfelder, J.R.

    2008-01-01

    We examined the hypothesis that sulfide drives arsenic mobilization from pyritic black shale by a sulfide-arsenide exchange and oxidation reaction in which sulfide replaces arsenic in arsenopyrite forming pyrite, and arsenide (As-1) is concurrently oxidized to soluble arsenite (As+3). This hypothesis was tested in a series of sulfide-arsenide exchange experiments with arsenopyrite (FeAsS), homogenized black shale from the Newark Basin (Lockatong formation), and pyrite isolated from Newark Basin black shale incubated under oxic (21% O2), hypoxic (2% O2, 98% N2), and anoxic (5% H2, 95% N2) conditions. The oxidation state of arsenic in Newark Basin black shale pyrite was determined using X-ray absorption-near edge structure spectroscopy (XANES). Incubation results show that sulfide (1 mM initial concentration) increases arsenic mobilization to the dissolved phase from all three solids under oxic and hypoxic, but not anoxic conditions. Indeed under oxic and hypoxic conditions, the presence of sulfide resulted in the mobilization in 48 h of 13-16 times more arsenic from arsenopyrite and 6-11 times more arsenic from isolated black shale pyrite than in sulfide-free controls. XANES results show that arsenic in Newark Basin black shale pyrite has the same oxidation state as that in FeAsS (-1) and thus extend the sulfide-arsenide exchange mechanism of arsenic mobilization to sedimentary rock, black shale pyrite. Biologically active incubations of whole black shale and its resident microorganisms under sulfate reducing conditions resulted in sevenfold higher mobilization of soluble arsenic than sterile controls. Taken together, our results indicate that sulfide-driven arsenic mobilization would be most important under conditions of redox disequilibrium, such as when sulfate-reducing bacteria release sulfide into oxic groundwater, and that microbial sulfide production is expected to enhance arsenic mobilization in sedimentary rock aquifers with major pyrite-bearing, black

  1. Luminescence of high-doped calcium sulfide crystals

    International Nuclear Information System (INIS)

    Calcium sulfide crystals grown by high-temperatur mineralization tecnique have been studied. Bands peaked at 2.12 and 2.5-2.7 eV are considered the most invariable features of cathodoluminescence and photoluminescence spectra. It has been found that the 2.12 eV band is conditioned by optical electronic transitions in Mn2+ ions substituted for Ca2+ ions in the host lattice. The exciton mechanism of energy transfer to centers, that are responsible for the high-energy luminescence band, is discussed

  2. Hydrogen evolution on nano-particulate transition metal sulfides

    DEFF Research Database (Denmark)

    Bonde, Jacob Lindner; Moses, Poul Georg; Jaramillo, Thomas F.;

    2008-01-01

    The hydrogen evolution reaction (HER) on carbon supported MoS2 nanoparticles is investigated and compared to findings with previously published work on Au(111) supported MoS2. An investigation into MoS2 oxidation is presented and used to quantify the surface concentration of MoS2. Other metal...... sulfides with morphologies similar to MoS2 such as WS2, cobalt- promoted WS2, and cobalt-promoted MoS2 were also investigated in the search for improved HER activity. Experimental findings are compared to density functional theory (DFT) calculated values for the hydrogen binding energies (Delta G...

  3. Isolation and characterization of deodorizing bacteria for organic sulfide malodor

    Institute of Scientific and Technical Information of China (English)

    JIANG An-xi; LIU Bo; ZHAO Yang-guo; LI Zheng; BAI Yu; CHENG Yang-xue

    2004-01-01

    Strain Jll screened out from different odor origins can efficiently degrade methyl mercaptan and ethanethiol whereas has no ability to remove dimethyl sulfide. The results indicated that the strain Jll breaks only the C-SH bond. The optimum temperature and pH of Jll are 20-30℃ and 6.0-8.3 respectively. A systematic identification method-16S rDNA gene sequence comparison, for deodorizing bacteria was carried out. The 16S rDNA gene sequence analysis of strain Jll showed the highest level of 97% homology to Rape rhizosphere.

  4. Effect of mineral processing wastewater on flotation of sulfide minerals

    Institute of Scientific and Technical Information of China (English)

    CHEN Jian-ming; LIU Run-qing; SUN Wei; QIU Guan-zhou

    2009-01-01

    The effects of mineral processing wastewater on sulfide minerals were investigated by flotation, infrared spectrometry and electrochemistry test. The results show that lead-concentrate water can improve the flotation of galena, while the sulfur-concentrate water has negative effect on flotation of galena compared with distilled water. The flotation behavior of pyrite is contrary to that of galena in three kinds of water. Infrared spectra indicate that the residual collector in the lead-concentrate water is beneficial to the formation of lead xanthate on the surface of galena. Electrochemistry results indicate that electrochemistry reaction on galena surface has apparent change. The anode polarization is improved and cathode polarization is depressed.

  5. Dynamic corrosion of copper-nickel sulfide by Acidithiobacillus ferrooxidans

    Institute of Scientific and Technical Information of China (English)

    TONG Lin-lin; JIANG Mao-fa; YANG Hong-ying; YU Juan; FAN You-jing; ZHANG Yao

    2009-01-01

    The dynamic corrosion process of bio-oxidation of copper-nickel sulfide from Karatungk in northern Xinjiang Province of China was studied. The polished wafer of the copper-nickel sulphide was used to carry on a series of oxidation corrosion experiment by Acidithiobacillus ferrooxidans. The changes of superficial corrosion appearance and the mineral dynamic corrosion process were discovered by microscope observation. Then, the galvanic cell model was established, and the bio-oxidation activation order of typical copper-nickel sulphide minerals was ascertained as pyrrhotite>pentlandite>chalocopyrite.

  6. The summer of hydrogen sulfide: highlights from two international conferences

    OpenAIRE

    Calvert, John W

    2013-01-01

    A great deal of interest has been paid recently to the hydrogen sulfide, the newest member of the gasotransmitter family. With the growing interest in the biology of H2S, the need for meetings and conferences dedicated solely to the field of H2S has also grown. In 2009, scientist from around the world met in Shanghai, China for the first time to discuss the physiological relevance of H2S. In 2012, two conferences were organized to bring scientists, clinicians, and industry representatives tog...

  7. Surface-treatment of Alkaline Earth Sulfides Based Phosphor

    Institute of Scientific and Technical Information of China (English)

    GUO Chong-feng; CHU Ben-li; XU Jian; SU Qiang

    2004-01-01

    A series of alkaline earth sulfides based phosphors Ca0.8Sr0.2S∶Eu2+, Tm3+ were covered with a layer of protective coating with alkaline earth fluorides by heating the mixture of phosphor and NH4HF2 at elevated temperatures. The coatings were characterized by means of XRD and SEM. The optical properties of the coated phosphors and the influences of the coating on their properties have been discussed extensively. The stabilities of the coated and uncoated phosphors have been compared.

  8. Iron (III) sulfide particles produced by a polyol method

    Science.gov (United States)

    Shimizu, Ryo; Kubono, Ippei; Kobayashi, Yoshio; Yamada, Yasuhiro

    2015-04-01

    Iron(III) sulfide Fe2S3 particles were produced using a polyol method. Although pyrrhotite Fe1-xS appeared together with Fe2S3, the relative yield of Fe2S3 changed when the concentration of reagents in the oleylamine changed. Mössbauer spectra of the particles showed superparamagnetic doublets due to Fe2S3 at 293 K, along with a hyperfine magnetic splitting of H = 24.7 T at 6 K. XRD patterns of the Fe2S3 suggested a structure similar to that of greigite Fe3S4.

  9. Zinc sulfide in intestinal cell granules of Ancylostoma caninum adults

    Energy Technology Data Exchange (ETDEWEB)

    Gianotti, A.J.; Clark, D.T.; Dash, J. (Portland State Univ., OR (USA))

    1991-04-01

    A source of confusion has existed since the turn of the century about the reddish brown, weakly birefringent 'sphaerocrystals' located in the intestines of strongyle nematodes, Strongylus and Ancylostoma. X-ray diffraction and energy dispersive spectrometric analyses were used for accurate determination of the crystalline order and elemental composition of the granules in the canine hookworm Ancylostoma caninum. The composition of the intestinal pigmented granules was identified unequivocally as zinc sulfide. It seems most probable that the granules serve to detoxify high levels of metallic ions (specifically zinc) present due to the large intake of host blood.

  10. Therapeutic application of hydrogen sulfide donors: the potential and challenges.

    Science.gov (United States)

    Wu, Dan; Hu, Qingxun; Zhu, Yizhun

    2016-03-01

    Hydrogen sulfide (H2S), a colorless gas smelling of rotten egg, has long been considered a toxic gas and environment hazard. However, evidences show that H2S plays a great role in many physiological and pathological activities, and it exhibits different effects when applied at various doses. In this review, we summarize the chemistry and biomedical applications of H2S-releasing compounds, including inorganic salts, phosphorodithioate derivatives, derivatives of Allium sativum extracts, derivatives of thioaminoacids, and derivatives of antiinflammatory drugs. PMID:26597301

  11. Rice: Sulfide-induced Barriers to Root Radial Oxygen Loss, Fe2+ and Water Uptake, and Lateral Root Emergence

    OpenAIRE

    ARMSTRONG, JEAN; Armstrong, William (Canadian painter, civil engineer, photographer, 1822-1914)

    2005-01-01

    • Background and Aims Akagare and Akiochi are diseases of rice associated with sulfide toxicity. This study investigates the possibility that rice reacts to sulfide by producing impermeable barriers in roots.

  12. Sulfide intrusion in seagrasses assessed by stable sulfur isotopes—a synthesis of current results

    DEFF Research Database (Denmark)

    Holmer, Marianne; Hasler-Sheetal, Harald

    2014-01-01

    Sulfide intrusion in seagrasses, as assessed by stable sulfur isotope signals, is widespread in all climate zones, where seagrasses are growing. Seagrasses can incorporate substantial amounts of 34S-depleted sulfide into their tissues with up to 87% of the total sulfur in leaves derived from sedi...

  13. The impact of electrogenic sulfide oxidation on elemental cycling and solute fluxes in coastal sediment

    NARCIS (Netherlands)

    Rao, A.M.F.; Malkin, S.Y.; Hidalgo-Martinez, S.; Meysman, Filip

    2016-01-01

    Filamentous sulfide oxidizing cable bacteria are capable of linking the oxidation of free sulfide in deep anoxic layers of marine sediments to the reduction of oxygen or nitrate in surface sediments by conducting electrons over centimeter-scale distances. Previous studies have shown that this newly

  14. Electron microscopy investigation of the microstructure of unsupported Ni-Mo-W sulfide

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, B.S. [Department of Inorganic Chemistry, Fritz Haber Institute of the Max Planck Society, Faradayweg 4-6, 14195 Berlin (Germany); Yi, Y.J. [Laboratory of Advanced Materials and Catalytic Engineering, School of Chemical Engineering, Dalian University of Technology, 158 Zhongshan Road, 116012 Dalian (China); Zhang, W. [Department of Inorganic Chemistry, Fritz Haber Institute of the Max Planck Society, Faradayweg 4-6, 14195 Berlin (Germany); Liang, C.H. [Laboratory of Advanced Materials and Catalytic Engineering, School of Chemical Engineering, Dalian University of Technology, 158 Zhongshan Road, 116012 Dalian (China); Su, D.S., E-mail: dangsheng@fhi-berlin.mpg.de [Department of Inorganic Chemistry, Fritz Haber Institute of the Max Planck Society, Faradayweg 4-6, 14195 Berlin (Germany)

    2011-07-15

    An exploration was made on structure and active sites of the unsupported Ni-Mo-W sulfide hydrodesulphurization catalyst prepared by a thiosalt decomposition method. More insights into the nanocomposite structure were provided by introducing the concept of average curvature of Mo(W)S{sub 2} and establishing a new structure model. The defects of cross and mixed stacks, steps along c-axis, expansion of (002) interplanar spacing and mixing structure of Mo(W)/Ni sulfides were investigated using advanced electron microscopy. All these defects in Mo(W) sulfides are closely correlated with increasing active sites of unsupported Ni-Mo-W sulfide catalyst. - Graphical Abstract: From the top schematic of unsupported Ni-Mo-W sulfide, the MoS{sub 2}, WS{sub 2}, or Mo{sub x}W{sub 1-x}S{sub 2} are surrounded by the dispersed Ni sulfide, which make the formation of nanocomposite phases possible. For the bottom colorized high-resolution transmission electron microscopy image with 3D rotation, the variation in sample thickness leads to a varying representation of the contrast of the Ni-Mo-W sulfide sheet, ... Research Highlights: {yields} Rich microstructural features of unsupported Ni-Mo-W sulfide catalyst were revealed. {yields} Curvature of HDS catalyst was firstly proposed, also illustrative for other catalysts. {yields} Insights into the nano-composite were gained from its new structure model.

  15. Inhibition of a biological sulfide oxidation under haloalkaline conditions by thiols and diorgano polysulfanes

    NARCIS (Netherlands)

    Roman, Pawel; Lipińska, Joanna; Bijmans, Martijn F.M.; Sorokin, Dimitry Y.; Keesman, Karel J.; Janssen, Albert J.H.

    2016-01-01

    A novel approach has been developed for the simultaneous description of reaction kinetics to describe the formation of polysulfide and sulfate anions from the biological oxidation of hydrogen sulfide (H2S) using a quick, sulfide-dependent respiration test. Next to H2S, thiol

  16. Inhibition of microbiological sulfide oxidation at natronophilic conditions by methanethiol and methylated polysulfides

    NARCIS (Netherlands)

    Bosch, van den P.L.F.; Graaff, de C.M.; Fortuny-Picornell, M.; Leerdam, van R.C.; Janssen, A.J.H.

    2009-01-01

    To avoid problems related to the discharge of sulfidic spent caustics, a biotechnological process is developed for the treatment of gases containing both hydrogen sulfide and methanethiol. The process operates at natron-alkaline conditions (>1 mol L-1 of sodium- and potassium carbonates and a pH

  17. Synthetic Fabrication of Nanoscale MoS2-Based Transition Metal Sulfides

    Directory of Open Access Journals (Sweden)

    Jikang Yuan

    2010-01-01

    Full Text Available Transition metal sulfides are scientifically and technologically important materials. This review summarizes recent progress on the synthetic fabrication of transition metal sulfides nanocrystals with controlled shape, size, and surface functionality. Special attention is paid to the case of MoS2 nanoparticles, where organic (surfactant, polymer, inorganic (support, promoter, doping compounds and intercalation chemistry are applied.

  18. Growth kinetics of hydrogen sulfide oxidizing bacteria in corroded concrete from sewers.

    Science.gov (United States)

    Jensen, Henriette Stokbro; Lens, Piet N L; Nielsen, Jeppe L; Bester, Kai; Nielsen, Asbjørn Haaning; Hvitved-Jacobsen, Thorkild; Vollertsen, Jes

    2011-05-30

    Hydrogen sulfide oxidation by microbes present on concrete surfaces of sewer pipes is a key process in sewer corrosion. The growth of aerobic sulfur oxidizing bacteria from corroded concrete surfaces was studied in a batch reactor. Samples of corrosion products, containing sulfur oxidizing bacteria, were suspended in aqueous solution at pH similar to that of corroded concrete. Hydrogen sulfide was supplied to the reactor to provide the source of reduced sulfur. The removal of hydrogen sulfide and oxygen was monitored. The utilization rates of both hydrogen sulfide and oxygen suggested exponential bacterial growth with median growth rates of 1.25 d(-1) and 1.33 d(-1) as determined from the utilization rates of hydrogen sulfide and oxygen, respectively. Elemental sulfur was found to be the immediate product of the hydrogen sulfide oxidation. When exponential growth had been achieved, the addition of hydrogen sulfide was terminated leading to elemental sulfur oxidation. The ratio of consumed sulfur to consumed oxygen suggested that sulfuric acid was the ultimate oxidation product. To the knowledge of the authors, this is the first study to determine the growth rate of bacteria involved in concrete corrosion with hydrogen sulfide as source of reduced sulfur.

  19. Growth kinetics of hydrogen sulfide oxidizing bacteria in corroded concrete from sewers

    International Nuclear Information System (INIS)

    Hydrogen sulfide oxidation by microbes present on concrete surfaces of sewer pipes is a key process in sewer corrosion. The growth of aerobic sulfur oxidizing bacteria from corroded concrete surfaces was studied in a batch reactor. Samples of corrosion products, containing sulfur oxidizing bacteria, were suspended in aqueous solution at pH similar to that of corroded concrete. Hydrogen sulfide was supplied to the reactor to provide the source of reduced sulfur. The removal of hydrogen sulfide and oxygen was monitored. The utilization rates of both hydrogen sulfide and oxygen suggested exponential bacterial growth with median growth rates of 1.25 d-1 and 1.33 d-1 as determined from the utilization rates of hydrogen sulfide and oxygen, respectively. Elemental sulfur was found to be the immediate product of the hydrogen sulfide oxidation. When exponential growth had been achieved, the addition of hydrogen sulfide was terminated leading to elemental sulfur oxidation. The ratio of consumed sulfur to consumed oxygen suggested that sulfuric acid was the ultimate oxidation product. To the knowledge of the authors, this is the first study to determine the growth rate of bacteria involved in concrete corrosion with hydrogen sulfide as source of reduced sulfur.

  20. 30 CFR 250.215 - What hydrogen sulfide (H2S) information must accompany the EP?

    Science.gov (United States)

    2010-07-01

    ... methodologies outlined in 40 CFR part 68. ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false What hydrogen sulfide (H2S) information must... Contents of Exploration Plans (ep) § 250.215 What hydrogen sulfide (H2S) information must accompany the...

  1. Amperometric inhibitive biosensor based on horseradish peroxidase-nanoporous gold for sulfide determination

    Science.gov (United States)

    Sun, Huihui; Liu, Zhuang; Wu, Chao; Xu, Ping; Wang, Xia

    2016-08-01

    As a well-known toxic pollutant, sulfide is harmful to human health. In this study, a simple and sensitive amperometric inhibitive biosensor was developed for the determination of sulfide in the environment. By immobilizing nanoporous gold (NPG) on glassy carbon electrode (GCE), and encapsulating horseradish peroxidase (HRP) onto NPG, a HRP/NPG/GCE bioelectrode for sulfide detection was successfully constructed based on the inhibition of sulfide on HRP activity with o-Phenylenediamine (OPD) as a substrate. The resulted HRP/NPG/GCE bioelectrode achieved a wide linear range of 0.1–40 μM in sulfide detection with a high sensitivity of 1720 μA mM‑1 cm‑2 and a low detection limit of 0.027 μM. Additionally, the inhibition of sulfide on HRP is competitive inhibition with OPD as a substrate by Michaelis-Menten analysis. Notably, the recovery of HRP activity was quickly achieved by washing the HRP/NPG/GCE bioelectrode using differential pulse voltammetry (DPV) technique in deaerated PBS (50 mM, pH 7.0) for only 60 s. Furthermore, the real sample analysis of sulfide by the HRP/NPG/GCE bioelectrode was achieved. Based on above results, the HRP/NPG/GCE bioelectrode could be a better choice for the real determination of sulfide compared to inhibitive biosensors previously reported.

  2. Sulfide oxidation at halo-alkaline conditions in a fed-batch bioreactor

    NARCIS (Netherlands)

    Bosch, van den P.L.F.; Beusekom, van O.C.; Buisman, C.J.N.; Janssen, A.J.H.

    2007-01-01

    A biotechnological process is described to remove hydrogen sulfide (H2S) from high-pressure natural gas and sour gases produced in the petrochemical industry. The process operates at halo-alkaline conditions and combines an aerobic sulfide-oxidizing reactor with an anaerobic sulfate (SO) and thiosul

  3. A STUDY TO EVALUATE CARBON MONOXIDE AND HYDROGEN SULFIDE CONTINUOUS EMISSION MONITORS AT AN OIL REFINERY

    Science.gov (United States)

    An eleven month field evaluation was done on five hydrogen sulfide and four carbon monoxide monitors located at an oil refinery. The hydrogen sulfide monitors sampled a fuel gas feed line and the carbon monoxide monitors sampled the emissions from a fluid cat cracker (FCC). Two o...

  4. The sampling of hydrogen sulfide in air with impregnated filter paper

    NARCIS (Netherlands)

    Huygen, C.

    1964-01-01

    A method is proposed for the quantitative collection of hydrogen sulfide in air on impregnated filter paper. An aqueous solution of potassium hydroxide, potassium zincate and glycerol is used as impregnating fluid. The stability of the collected sulfide and the efficiency of collection at different

  5. Zinc stable isotope fractionation upon accelerated oxidative weathering of sulfidic mine waste.

    Science.gov (United States)

    Matthies, R; Krahé, L; Blowes, D W

    2014-07-15

    Accelerated oxidative weathering in a reaction cell (ASTM D 5744 standard protocol) was performed over a 33 week period on well characterized, sulfidic mine waste from the Kidd Creek Cu-Zn volcanogenic massive sulfide deposit, Canada. The cell leachate was monitored for physicochemical parameters, ion concentrations and stable isotope ratios of zinc. Filtered zinc concentrations (weathering processes in complex multi-phase matrices.

  6. Spin-polarized quasiparticle transport in exchange-split superconducting aluminum on europium sulfide

    Science.gov (United States)

    Wolf, M. J.; Sürgers, C.; Fischer, G.; Beckmann, D.

    2014-10-01

    We report on nonlocal spin transport in mesoscopic superconducting aluminum wires in contact with the ferromagnetic insulator europium sulfide. We find spin injection and long-range spin transport in the regime of the exchange splitting induced by europium sulfide. Our results demonstrate that spin transport in superconductors can be manipulated by ferromagnetic insulators, and opens a path to control spin currents in superconductors.

  7. Anaerobic sulfide-oxidation in marine colorless sulfur-oxidizing bacteria

    Digital Repository Service at National Institute of Oceanography (India)

    LokaBharathi, P.A.; Nair, S.; Chandramohan, D.

    50 degrees C decreased cell viability and consequently sulfide oxidation was negligible. Cell viability as estimated by the colony-forming ability decreased 100-fold after the exposure to 100 kg/cm sup(2) pressure for 1 h. Both viability and sulfide...

  8. Why does the Conductivity of a Nickel Catalyst Increase during Sulfidation? An Exemplary Study Using an In Operando Sensor Device

    OpenAIRE

    Peter Fremerey; Andreas Jess; Ralf Moos

    2015-01-01

    In order to study the sulfidation of a catalyst fixed bed, an in operando single pellet sensor was designed. A catalyst pellet from the fixed bed was electrically contacted and its electrical response was correlated with the catalyst behavior. For the sulfidation tests, a nickel catalyst was used and was sulfidized with H2S. This catalyst had a very low conductivity in the reduced state. During sulfidation, the conductivity of the catalyst increased by decades. A reaction from nickel to nicke...

  9. Biological conversion of hydrogen sulfide into elemental sulfur

    Energy Technology Data Exchange (ETDEWEB)

    Basu, R.; Clausen, E.C.; Gaddy, J.L. [Bioengineering Resources, Inc., Fayetteville, AR (United States)

    1996-12-31

    Currently, hydrogen sulfide is removed from process gas streams by a series of reactions at high temperature to produce elemental sulfur in Claus, Stretford or other processes. These physicochemical processes have high intrinsic capital and operating costs, often are restricted by contaminants, and do not effectively remove all the H{sub 2}S. As an alternative, the anaerobic, photosynthetic bacterium, Chlorobium thiosulfatophilum, has been demonstrated to convert hydrogen sulfide to elemental sulfur in a single step at atmospheric conditions. The autotrophic bacterium uses CO{sub 2} as the carbon source. Energy for cell metabolism is provided by incandescent light and the oxidation of H{sub 2}S. A bench scale study has been performed in a CSTR equipped with a sulfur separator. Optimum process conditions have been achieved to maximize cell growth and elemental sulfur production. Near total conversion of H{sub 2}S is achieved in a retention time of a few minutes. High concentrations of H{sub 2}S or organics do not affect the culture. Sulfur recovery by settling is very efficient and near theoretical yields of sulfur are achieved. Economic projections indicate that sour gas can be desulfurized for $0.08-0.12/MSCF. 13 refs.

  10. Reactions of ruthenium hydrides with ethyl-vinyl sulfide.

    Science.gov (United States)

    Dahcheh, Fatme; Stephan, Douglas W

    2014-03-01

    The Ru-hydride precursors (Im(OMe)2)(PPh3)2RuHCl () and (Me2Im(OMe)2)(PPh3)2RuHCl () reacted with ethyl-vinyl-sulfide to give ((MeOCH2CH2)C3H2N2(CH2CH(OMe))RuCl(PPh3)2 () and ((MeOCH2CH2)C3Me2N2(CH2CH(OMe))RuCl(PPh3)2 (), respectively. Dissolution of () in C6D6 prompts formation of ((MeOCH2CH2)C5H6N2(CHCH)RuCl(PPh3)2 (). The analogous reactions of the bis-carbene Ru-hydride precursors (Im(OMe)2)(IMes)(PPh3)RuHCl (), (Im(OMe)2)(SIMes)(PPh3)RuHCl () and (Im(OMe)2)(IMes-Cl2)(PPh3)RuHCl () gave ((MeOCH2CH2)C3H2N2(CHCH)RuCl(PPh3)(NHC) (NHC = IMes (), SIMes (), IMes-Cl2 (), respectively. The formation of compounds () and () is thought to go through an initial insertion of the vinyl-fragment into the Ru-H prompting subsequent C-H activation and loss of diethyl sulfide. This yields () and (), while subsequent loss of methanol yields () and (-). PMID:24441082

  11. Control of microbially generated hydrogen sulfide in produced waters

    Energy Technology Data Exchange (ETDEWEB)

    Burger, E.D.; Vance, I.; Gammack, G.F.; Duncan, S.E.

    1995-12-31

    Production of hydrogen sulfide in produced waters due to the activity of sulfate-reducing bacteria (SRB) is a potentially serious problem. The hydrogen sulfide is not only a safety and environmental concern, it also contributes to corrosion, solids formation, a reduction in produced oil and gas values, and limitations on water discharge. Waters produced from seawater-flooded reservoirs typically contain all of the nutrients required to support SRB metabolism. Surface processing facilities provide a favorable environment in which SRB flourish, converting water-borne nutrients into biomass and H{sub 2}S. This paper will present results from a field trial in which a new technology for the biochemical control of SRB metabolism was successfully applied. A slip stream of water downstream of separators on a produced water handling facility was routed through a bioreactor in a side-steam device where microbial growth was allowed to develop fully. This slip stream was then treated with slug doses of two forms of a proprietary, nonbiocidal metabolic modifier. Results indicated that H{sub 2}S production was halted almost immediately and that the residual effect of the treatment lasted for well over one week.

  12. Accelerating column leaching trial on copper sulfide ore

    Institute of Scientific and Technical Information of China (English)

    WANG Hongjiang; WU Aixiang; ZHOU Xun; WANG Shaoyong; ZHANG Jie

    2008-01-01

    The main measures to accelerate leaching sulfide ore are large spraying intensity,manual oxygen supply,temperature control and acclimated bacteria.The indoor experiment accelerating sulfide ore leaching detected the temperature during leaching process,dissolvability of oxygen,bacterial concentration,Cu concentration and slag grade.At the same time,this paper also analyzed the effect of four factors,which are bacterial diversity cultivation stage,spraying intensity,air supply,and whether to control temperature,on the leaching efficiency of copper.The results indicate that the oxygen content of leach solution has a close relationship with temperature but it is rarely affected by air supply.The bacterial concentration preserves from 106 to 107 mL-1,and temperature has a great effect on the bacterial activity under the condition of proper temperature and oxygen supply,and the lack of nutrition prevents the bacterial concentration from rising in the late stage.The relationships of the copper leaching efficiency to temperature,air feed,and spraying intensity are directly proportional.The leaching efficiencies of the cultivated bacteria and acclimation bacteria are 1.2 and 1.4 times as large as that of the original bacteria.

  13. Sulfide mineralization: Its role in chemical weathering of Mars

    Science.gov (United States)

    Burns, Roger G.

    1988-01-01

    Pyrrhotite-pentlandite assemblages in mafic and ultramafic igneous rocks may have contributed significantly to the chemical weathering reactions that produced degradation products in the Martian regolith. By analogy with terrestrial processes, a model is proposed whereby supergene alteration of these primary Fe-Ni sulfides on Mars has generated secondary sulfides (e.g., pyrite) below the water table and produced acidic groundwater containing high concentrations of dissolved Fe, Ni and sulfate ions. The low pH solutions also initiated weathering reactions of igneous feldspars and ferromagnesian silicates to form clay silicate and ferric oxyhydroxide phases. Near-surface oxidation and hydrolysis of ferric sulfato- and hydroxo-complex ions and sols formed gossans above the water table consisting of poorly crystalline hydrated ferric sulfates (e.g., jarosite), oxides (ferrihydrite, goethite) and silica (opal). Underlying groundwater, now permafrost, contains hydroxo sulfato complexes of Fe, Al, Mg, Ni, etc., which may be stabilized in frozen acidic solutions beneath the surface of Mars. Sublimation of permafrost may replenish colloidal ferric oxides, sulfates and phyllosilicates during dust storms on Mars.

  14. Bioleaching of low grade nickel sulfide mineral in column reactor

    Institute of Scientific and Technical Information of China (English)

    ZHEN Shi-jie; QIN Wen-qing; YAN Zhong-qiang; ZHANG Yan-sheng; WANG Jun; REN Liu-yi

    2008-01-01

    Jinchuan low grade nickel (0.4%-0.6% Ni,mass fraction) sulfide mineral ore contains a remarkably high content of magnesia (30%-35% MgO,mass fraction) present in the main gangue minerals.Bioleaching was performed to investigate the feasibility to process the mineral due to its relative simplicity,eco-friendly operation and low capital cost requirements.The mixed mesophiles were enriched from acid mine drainage samples collected from several acid mines in China.Considering that the magnesia is easily extracted by acid solution and the excessive Mg2+ will exceed the tolerance of the mixed mesophiles,three effective means were used to reduce the disadvantage of magnesia during the bioleaching operation.They were adaptation of the mixed mesophiles to improve the tolerance; pre-leaching to remove most leachable magnesia and periodic bleeds of a portion of the pregnant leaching solution to control the level of Mg2+ based on the tolerance of the mixed mesophiles.An extraction of nickel (90.3%) and cobalt (88.6%) was successfully achieved within a 300 d leaching process from the Jinchuan low grade nickel sulfide mineral ore using a column reactor at ambient temperature.

  15. Heavy Metals in a Sulfidic Minespoil: Fractions and Column Leaching

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Fractions of various heavy metals in a sulfidic minespoil were investigated. Column leaching experimentwas also conducted to simulate "acid mine drainage" (AMD) from the minespoil. The results show thatleaching of heavy metals from the minespoil was extremely significant during the initial water flushing.The amounts of heavy metals leached out dramatically reduced after leaching twice. It is worthwhile tonote that in this study, Zn, Mn, Fe, As and Ni in the first leachate exceeded the total amount of eachcorresponding water-extractable (1:5, soil:water) metal contained in the minespoil sample. This appears tosuggest that 1:5 water extraction did not allow accurate estimation of water-leachable concentrations of theabove heavy metals. This work has implications for the management of sulfidic minespoils. Acid drainageof great environmental concerns is likely to occur only during heavy rainfall events after substantial solubleand readily exchangeable acid and metals are accumulated in the minespoils. The slow-reacting fractionsother than water-soluble and readily exchangeable fractions may pose little environmental hazards. This isparticularly true for Pb, As and Ni.

  16. Atmospheric Sulfur Cycle Effects of Carbonyl Sulfide (OCS)

    Science.gov (United States)

    McBee, Joshua

    1996-01-01

    Carbonyl Sulfide(OCS) is considered to be one of the major sources of sulfur appearing in the stratosphere due to its relative inertness, about I to 10 yearsl. However, the roles of OCS as well as other reduced sulfur compounds such as carbon disulfide (CS2), hydrogen sulfide (H2S), and dimethyl disulfide(CH3)2S2, are not completely understood in the atmosphenc sulfur cycle. Consequently vely little information is available about the effect of sulfur compounds in the stratosphere. The ability of OCS to penetrate into the stratosphere makes it an excellent tracer for study of the role of the sulfi r cycle in stratospheric chemistry. Previously techniques such as gas chromatography and whole air sampling have been used to measure OCS analytically. Each technique had its drawbacks however, with both being quite slow, and whole air sampling being somewhat unreliable. With molecular spectroscopy, however, it has been found in recent years that the tunable diode laser absorption spectrometer (TDL) provides a very rapid and accurate method of measuring OCS and other trace gases

  17. Hydrogen sulfide intervention in focal cerebral ischemia/reperfusion injury in rats

    Directory of Open Access Journals (Sweden)

    Xin-juan Li

    2015-01-01

    Full Text Available The present study aimed to explore the mechanism underlying the protective effects of hydrogen sulfide against neuronal damage caused by cerebral ischemia/reperfusion. We established the middle cerebral artery occlusion model in rats via the suture method. Ten minutes after middle cerebral artery occlusion, the animals were intraperitoneally injected with hydrogen sulfide donor compound sodium hydrosulfide. Immunofluorescence revealed that the immunoreactivity of P2X 7 in the cerebral cortex and hippocampal CA1 region in rats with cerebral ischemia/reperfusion injury decreased with hydrogen sulfide treatment. Furthermore, treatment of these rats with hydrogen sulfide significantly lowered mortality, the Longa neurological deficit scores, and infarct volume. These results indicate that hydrogen sulfide may be protective in rats with local cerebral ischemia/reperfusion injury by down-regulating the expression of P2X 7 receptors.

  18. What do we really know about the role of microorganisms in iron sulfide mineral formation?

    Science.gov (United States)

    Picard, Aude; Gartman, Amy; Girguis, Peter

    2016-06-01

    Iron sulfide mineralization in low-temperature systems is a result of biotic and abiotic processes, though the delineation between these two modes of formation is not always straightforward. Here we review the role of microorganisms in the precipitation of extracellular iron sulfide minerals. We summarize the evidence that links sulfur-metabolizing microorganisms and sulfide minerals in nature and we present a critical overview of laboratory-based studies of the nucleation and growth of iron sulfide minerals in microbial cultures. We discuss whether biologically derived minerals are distinguishable from abiotic minerals, possessing attributes that are uniquely diagnostic of biomineralization. These inquiries have revealed the need for additional thorough, mechanistic and high-resolution studies to understand microbially mediated formation of a variety of sulfide minerals across a range of natural environments.

  19. Synthesis of rare earth sulfides and their UV-vis absorption spectra

    Institute of Scientific and Technical Information of China (English)

    YUAN Haibin; ZHANG Jianhui; YU Ruijin; SU Qiang

    2009-01-01

    Rare earth sulfides were systematically synthesized via the sulfurization of their commercial oxide powders using CS2 gas to shorten sulfurization time, and their UV-vis absorption spectra were investigated. The appropriate sulfurization conditions were studied. For the rare earth sulfides with the same crystal structure, the sulfurization temperature showed increasing tendency with the decrease of rare earth element atomic radii. The UV-vis absorption spectra of rare earth sulfides did not depend on the crystal structure of rare earth sulfides, but on the 4f electronic structure of rare earth element. The data showed that the optical band gaps of rare earth sulfides were irregular, and the values ranged from 1.65 to 3.75 eV.

  20. Reliability of Electrochemical Techniques for Determining Corrosion Rates on Carbon Steel in Sulfide Media

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel; Hemmingsen, T.; Nielsen, Lars Vendelbo;

    2007-01-01

    Effects of film formation on carbon steel in hydrogen sulfide (H2S) media may corrupt corrosion rate monitoring by electrochemical techniques. Electrochemical data from H2S solutions, biological sulfide media, and natural sulfide containing geothermal water have been collected, and the process...... of film formation in sulfide solutins was followed by video. It can be shown that capacitative and diffusional effects due to porous reactive deposits tend to dominate the data, resulting in unreliable corrosion rates measured using electrochemical techniques. The effect is strongly increased...... if the biofilm in combination with ferrous sulfide corrosion products cover the steel surface. Corrosion rates can be overestimated by a factor of 10 to 100 with electrochemical techniques - both by linear polarization resistance (LPR) and electrochemicel impedance spectroscopy (EIS). Oxygen entering the system...

  1. Hydrogen sulfide intervention in focal cerebral ischemia/reperfusion injury in rats.

    Science.gov (United States)

    Li, Xin-Juan; Li, Chao-Kun; Wei, Lin-Yu; Lu, Na; Wang, Guo-Hong; Zhao, Hong-Gang; Li, Dong-Liang

    2015-06-01

    The present study aimed to explore the mechanism underlying the protective effects of hydrogen sulfide against neuronal damage caused by cerebral ischemia/reperfusion. We established the middle cerebral artery occlusion model in rats via the suture method. Ten minutes after middle cerebral artery occlusion, the animals were intraperitoneally injected with hydrogen sulfide donor compound sodium hydrosulfide. Immunofluorescence revealed that the immunoreactivity of P2X7 in the cerebral cortex and hippocampal CA1 region in rats with cerebral ischemia/reperfusion injury decreased with hydrogen sulfide treatment. Furthermore, treatment of these rats with hydrogen sulfide significantly lowered mortality, the Longa neurological deficit scores, and infarct volume. These results indicate that hydrogen sulfide may be protective in rats with local cerebral ischemia/reperfusion injury by down-regulating the expression of P2X7 receptors.

  2. Influence of sulfides on the tribological properties of composites produced by pulse electric current sintering

    Institute of Scientific and Technical Information of China (English)

    Seung Ho Kim

    2014-01-01

    Self-lubricating Al2O3-15wt%ZrO2 composites with sulfides, such as molybdenum disulfide (MoS2) and tungsten disulfide (WS2) serving as solid lubricants, were fabricated by using the pulse electric current sintering (PECS) technique. The coefficient of friction (COF) of the Al2O3-15wt%ZrO2 composite without/with sulfides was in the range of 0.37-0.48 and 0.27-0.49, respectively. As the amount of sul-fides increased, the COF and the wear rate decreased. The reduction in COF and wear rate of the sulfide-containing composite is caused by a reduction in shear stresses between the specimen and the tribological medium due to the formation of a lubricating film resulting from the lamellar structure of sulfides located on the worn surface.

  3. A NEW BIOGENIC SULFIDE CHEMICAL SENSOR FOR MARINE ENVIRONMENTAL MONITORING AND SURVEY

    Institute of Scientific and Technical Information of China (English)

    宋金明; 赵卫东

    2001-01-01

    A new convenient sulfide electrochemical sensor for marine environmental insitumonitoring and real time survey was developed. The new sensor based on a solid Ag2 S membrane electrode has outstanding chemical sensitivity and stability. It responds to the activity of sulfide ions according to a Nernsfian slope of - 31mV/decade. The sensor can be used to determine the total concentration of sulfides ( CT ) by calibrating the pH value of the solution to a standard pH. The practical measurement range for total sulfide concentration is 0.1 - 10 mg/L in seawater. The sensor has a very low potential drift ( < 4mV) during two months in 0.1 mg/L sulfide seawater. This paper describes the preparation of the sensitive membrane and some main properties of the sensor.

  4. A NEW BIOGENIC SULFIDE CHEMICAL SENSOR FOR MARINE ENVIRONMENTAL MONITORING AND SURVEY

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A new convenient sulfide electrochemical sensor for marine environmental in-situ monitoring and real time survey was developed. The new sensor based on a solid Ag2S membrane electrode has outstanding chemical sensitivity and stability. It responds to the activity of sulfide ions according to a Nernstian slope of -31mV/decade. The sensor can be used to determine the total concentration of sulfides (CT) by calibrating the pH value of the solution to a standard pH. The practical measurement range for total sulfide concentration is 0.1-10 mg/L in seawater. The sensor has a very low potential drift (<4mV) during two months in 0.1 mg/L sulfide seawater. This paper describes the preparation of the sensitive membrane and some main properties of the sensor.

  5. Influence of sulfides on the tribological properties of composites produced by pulse electric current sintering

    Science.gov (United States)

    Kim, Seung Ho

    2014-01-01

    Self-lubricating Al2O3-15wt% ZrO2 composites with sulfides, such as molybdenum disulfide (MoS2) and tungsten disulfide (WS2) serving as solid lubricants, were fabricated by using the pulse electric current sintering (PECS) technique. The coefficient of friction (COF) of the Al2O3-15wt% ZrO2 composite without/with sulfides was in the range of 0.37-0.48 and 0.27-0.49, respectively. As the amount of sulfides increased, the COF and the wear rate decreased. The reduction in COF and wear rate of the sulfide-containing composite is caused by a reduction in shear stresses between the specimen and the tribological medium due to the formation of a lubricating film resulting from the lamellar structure of sulfides located on the worn surface.

  6. Anoxic Transformations of Radiolabeled Hydrogen-Sulfide in Marine and Fresh-Water Sediments

    DEFF Research Database (Denmark)

    ELSGAARD, L.; JØRGENSEN, BB

    1992-01-01

    oxidation to sulfate. Thiosulfate was partly turned over by oxidation or disproportionation and was found to be an intermediate in the (SO4=)-S-35 formation. The results demonstrate that oxidative and reductive sulfur cycling may occur simultaneously in marine and freshwater sediments. When added......Radiolabeled hydrogen sulfide (HS-)-S-35 was used to trace the anoxic sulfur transformations in marine and freshwater sediment slurries. Time course studies consistently showed a rapid (S2O3=)-S-35 formation and a progressive accumulation of (SO4=)-S-35 and thus indicated an anoxic sulfide...... as exogenous oxidant, nitrate (NO3-) stimulated the anoxic sulfide oxidation to sulfate. Ferric iron, added in the form of lepidocrocite (gamma-FeOOH), caused the precipitation of iron sulfides and only partial sulfide oxidation to pyrite and elemental sulfur....

  7. Synthesis of Nanoporous Metals, Oxides, Carbides, and Sulfides: Beyond Nanocasting.

    Science.gov (United States)

    Luc, Wesley; Jiao, Feng

    2016-07-19

    metal oxides with bimodal pore size distributions can be obtained. Combining nanocasting with chemical etching, a cobalt oxide with a hierarchical porous structure was synthesized, which possessed a surface area up to 250 m(2) g(-1), representing the highest surface area reported to date for nanoporous cobalt oxides. Lastly, this Account also covers the syntheses of nanoporous metal carbides and sulfides. The combination of in situ carburization and nanocasting enabled the syntheses of two ordered nanoporous metal carbides, Mo2C and W2C. For nanoporous metal sulfides, an "oxide-to-sulfide" synthetic strategy was proposed to address the large volume change issue of converting metal nitrate precursors to metal sulfide products in nanocasting. The successful syntheses of ordered nanoporous FeS2, CoS2, and NiS2 demonstrated the feasibility of the "oxide-to-sulfide" method. Concluding remarks include a summary of recent advances in the syntheses of nanoporous metal-based solids and a brief discussion of future opportunities in the hope of stimulating new interests and ideas. PMID:27294847

  8. Synthesis of Nanoporous Metals, Oxides, Carbides, and Sulfides: Beyond Nanocasting.

    Science.gov (United States)

    Luc, Wesley; Jiao, Feng

    2016-07-19

    metal oxides with bimodal pore size distributions can be obtained. Combining nanocasting with chemical etching, a cobalt oxide with a hierarchical porous structure was synthesized, which possessed a surface area up to 250 m(2) g(-1), representing the highest surface area reported to date for nanoporous cobalt oxides. Lastly, this Account also covers the syntheses of nanoporous metal carbides and sulfides. The combination of in situ carburization and nanocasting enabled the syntheses of two ordered nanoporous metal carbides, Mo2C and W2C. For nanoporous metal sulfides, an "oxide-to-sulfide" synthetic strategy was proposed to address the large volume change issue of converting metal nitrate precursors to metal sulfide products in nanocasting. The successful syntheses of ordered nanoporous FeS2, CoS2, and NiS2 demonstrated the feasibility of the "oxide-to-sulfide" method. Concluding remarks include a summary of recent advances in the syntheses of nanoporous metal-based solids and a brief discussion of future opportunities in the hope of stimulating new interests and ideas.

  9. Nitrosopersulfide (SSNO− accounts for sustained NO bioactivity of S-nitrosothiols following reaction with sulfide

    Directory of Open Access Journals (Sweden)

    Miriam M. Cortese-Krott

    2014-01-01

    Full Text Available Sulfide salts are known to promote the release of nitric oxide (NO from S-nitrosothiols and potentiate their vasorelaxant activity, but much of the cross-talk between hydrogen sulfide and NO is believed to occur via functional interactions of cell regulatory elements such as phosphodiesterases. Using RFL-6 cells as an NO reporter system we sought to investigate whether sulfide can also modulate nitrosothiol-mediated soluble guanylyl cyclase (sGC activation following direct chemical interaction. We find a U-shaped dose response relationship where low sulfide concentrations attenuate sGC stimulation by S-nitrosopenicillamine (SNAP and cyclic GMP levels are restored at equimolar ratios. Similar results are observed when intracellular sulfide levels are raised by pre-incubation with the sulfide donor, GYY4137. The outcome of direct sulfide/nitrosothiol interactions also critically depends on molar reactant ratios and is accompanied by oxygen consumption. With sulfide in excess, a ‘yellow compound’ accumulates that is indistinguishable from the product of solid-phase transnitrosation of either hydrosulfide or hydrodisulfide and assigned to be nitrosopersulfide (perthionitrite, SSNO−; λmax 412 nm in aqueous buffers, pH 7.4; 448 nm in DMF. Time-resolved chemiluminescence and UV–visible spectroscopy analyses suggest that its generation is preceded by formation of the short-lived NO-donor, thionitrite (SNO−. In contrast to the latter, SSNO− is rather stable at physiological pH and generates both NO and polysulfides on decomposition, resulting in sustained potentiation of SNAP-induced sGC stimulation. Thus, sulfide reacts with nitrosothiols to form multiple bioactive products; SSNO− rather than SNO− may account for some of the longer-lived effects of nitrosothiols and contribute to sulfide and NO signaling.

  10. Carbonyl sulfide and dimethyl sulfide fluxes in an urban lawn and adjacent bare soil in Guangzhou, China

    Institute of Scientific and Technical Information of China (English)

    Zhigang Yi; Xinming Wang

    2011-01-01

    Carbonyl sulfide (COS) and dimethyl sulfide (DMS) fluxes from an urban Cynodon dactylon lawn and adjacent bare soil were measured during April-July 2005 in Guangzhou, China.Both the lawn and bare soil acted as sinks for COS and sources for DMS.The mean fluxes of COS and DMS in the lawn (-19.27 and 18.16 pmol/(m2·sec), respectively) were significantly higher than those in the bare soil (-9.89 and 9.35 pmol/(m2·sec), respectively).Fluxes of COS and DMS in mowed lawn were also higher than those in bare soils.Both COS and DMS fluxes showed diurnal variation with detectable but much lower values in the nighttime than in the daytime.COS fluxes were related significantly to temperature and the optimal temperature for COS uptake was 29℃.While positive linear correlations were found between DMS fluxes and temperature.COS fluxes increased linearly with ambient COS mixing ratios,and had a compensation point of 336 ppt.

  11. Replacive sulfide formation in anhydrite chimneys from the Pacmanus hydrothermal field, Papua New Guinea

    Science.gov (United States)

    Los, Catharina; Bach, Wolfgang; Plümper, Oliver

    2016-04-01

    Hydrothermal flow within the oceanic crust is an important process for the exchange of energy and mass between the lithosphere, hydrosphere and biosphere. Infiltrated seawater heats up and interacts with wall rock, causing mineral replacement reactions. These play a large role in the formation of ore deposits; at the discharge zone, a hot, acidic and metal-rich potential ore fluid exits the crust. It mixes with seawater and forms chimneys, built up of sulfate minerals such as anhydrite (CaSO4), which are subsequently replaced by sulfide minerals. Sulfide formation is related to fluid pathways, defined by cracks and pores in the sulfate chimney. Over time, these systems might develop into massive sulfide deposits. The big question is then: how is sulfate-sulfide replacement related to the evolution of rock porosity? To address this question, sulfide-bearing anhydrite chimneys from the Pacmanus hydrothermal field (Manus Basin, Papua New Guinea) were studied using X-ray tomography, EMPA, FIB-SEM and -TEM. The apparently massive anhydrite turns out highly porous on the micro scale, with sulfide minerals in anhydrite cleavage planes and along grain boundaries. The size of the sulfide grains relates to the pores they grew into, suggesting a tight coupling between dissolution (porosity generation) and growth of replacive minerals. Some of the sulfide grains are hollow and apparently used the dissolving anhydrite as a substrate to start growth in a pore. Another mode of sulfide development is aggregates of euhedral pyrite cores surrounded by colloform chalcopyrite. This occurrence implies that fluid pathways have remained open for some time to allow several stages of precipitation during fluid evolution. To start the replacement and to keep it going, porosity generation is crucial. Our samples show that dissolution of anhydrite occurred along pathways where fluid could enter, such as cleavage planes and grain boundaries. It appears that fluids ascending within the inner

  12. Nitrogen release from forest soils containing sulfide-bearing sediments

    Science.gov (United States)

    Maileena Nieminen, Tiina; Merilä, Päivi; Ukonmaanaho, Liisa

    2014-05-01

    Soils containing sediments dominated by metal sulfides cause high acidity and release of heavy metals, when excavated or drained, as the aeration of these sediments causes formation of sulfuric acid. Consequent leaching of acidity and heavy metals can kill tree seedlings and animals such as fish, contaminate water, and corrode concrete and steel. These types of soils are called acid sulfate soils. Their metamorphic equivalents, such as sulfide rich black shales, pose a very similar risk of acidity and metal release to the environment. Until today the main focus in treatment of the acid sulfate soils has been to prevent acidification and metal toxicity to agricultural crop plants, and only limited attention has been paid to the environmental threat caused by the release of acidity and heavy metals to the surrounding water courses. Even less attention is paid on release of major nutrients, such as nitrogen, although these sediments are extremely rich in carbon and nitrogen and present a potentially high microbiological activity. In Europe, the largest cover of acid sulfate soils is found in coastal lowlands of Finland. Estimates of acid sulfate soils in agricultural use range from 1 300 to 3 000 km2, but the area in other land use classes, such as managed peatland forests, is presumably larger. In Finland, 49 500 km2 of peatlands have been drained for forestry, and most of these peatland forests will be at the regeneration stage within 10 to 30 years. As ditch network maintenance is often a prerequisite for a successful establishment of the following tree generation, the effects of maintenance operations on the quality of drainage water should be under special control in peatlands underlain by sulfide-bearing sediments. Therefore, identification of risk areas and effective prevention of acidity and metal release during drain maintenance related soil excavating are great challenges for forestry on coastal lowlands of Finland. The organic and inorganic nitrogen

  13. Effects of Sulfidation on ZnO Nanoparticle Dissolution and Aggregation in Sulfate-Containing Suspensions.

    Science.gov (United States)

    Rasool, Kashif; Lee, Dae Sung

    2015-09-01

    Industrial metal oxide nanoparticles (NPs) have recently attracted considerable attention because of their potentially hazardous impacts on ecosystems and microbial colonies in biological wastewater treatment plants. NPs dissolution and aggregation greatly determine the fate of such NPs in the environment and are relevant to their potential toxicities. Hence, we investigated the effects of sulfate on the dissolution and aggregation of ZnO nanoparticles (ZnO-NPs). In addition, ZnO-NPs were sulfidized at different sulfide concentrations in an anaerobic abiotic environment to investigate the effects of sulfidation on ZnO-NPs aggregation and solubility. Increasing the sulfate concentration from 0 to 200 mg/L significantly increased ZnO-NPs dissolution from 3.99 to 6.18 mg Zn(2+)/L, whereas ZnO-NPs sulfidation reduced the Zn(2+) dissolution rate from 1.82 mg Zn(2+)/L for pristine ZnO-NPs to 0.59 mg Zn2+/L for sulfidized ones. Increasing the sulfate concentration and the sulfidation of the ZnO-NPs induced aggregation by suppressing electrostatic repulsion. The results indicate that the sulfidation of ZnO-NPs prevents the particle dissolution and is an attractive method of reducing their antimicrobial activity. PMID:26716331

  14. Sulfidation Roasting of Hemimorphite with Pyrite for the Enrichment of Zn and Pb

    Science.gov (United States)

    Min, Xiao-Bo; Xue, Ke; Ke, Yong; Zhou, Bo-Sheng; Li, Yang-Wen-Jun; Wang, Qing-Wei

    2016-09-01

    With the increasing consumption of zinc and the depletion of zinc sulfide ores, the exploitation of low-grade zinc oxide ores may be important for the sustainability of the zinc industry. Hemimorphite, a zinc hydroxyl silicate hydrate, is a significant source of Zn and Pb. It is difficult to obtain Zn and Pb from the hemimorphite using traditional technology. In this work, for the first time, sulfidation roasting of hemimorphite with pyrite was studied for the enrichment of Zn and Pb by a flotation process. Four stages of sulfidation roasting were determined based on x-ray diffraction and thermogravimetry analysis. Then, the effects of sulfidation temperature, pyrite dosage and reaction time on the sulfidation percentages were investigated at the laboratory scale. The experimental results showed that the sulfidation percentages of Pb and Zn were as high as 98.08% and 90.55% under optimum conditions, respectively. Finally, a flotation test was performed to enrich Zn and Pb in the sulfidation product. A flotation concentrate with 8.78% Zn and 9.25% Pb was obtained, and the recovery of Zn and Pb reached 56.14% and 75.94%, respectively.

  15. Effects of loading rate and hydraulic residence time on anoxic sulfide biooxidation

    Institute of Scientific and Technical Information of China (English)

    CAI Jing; ZHENG Ping; MAHMOOD Qaisar; ISLAM Ejazul; HU Bao-lan; WU Dong-lei

    2007-01-01

    The optimal operation conditions in an anoxic sulfide oxidizing (ASO) bioreactor were investigated. The maximal loading rates (LRs) observed through decreasing hydraulic retention time (HRT) at fixed substrate concentration are higher than those by increasing substrate concentration at fixed HRT. The sulfide oxidation in ASO reactor was partially producing both sulfate and sulfur; but the amount of sulfate produced was approximately one third that of sulfur. The process was able to tolerate high sulfide concentration, as the sulfide removal percentage always remained near 99% when influent concentration was up to 580 mg/L. It tolerated relatively lower nitrate concentration because the removal percentage dropped to 85% when influent concentration was increased above 110 mg/L. The process can tolerate shorter HRT but careful operation is needed. Nitrate conversion was more sensitive to HRT than sulfide conversion since the process performance deteriorated abruptly when HRT was decreased from 3.12 h to 2.88 h. In order to avoid nitrite accumulation in the reactor, the influent sulfide and nitrate concentrations should be kept at 280 mg/L and 67.5 mg/L respectively. Present biotechnology is useful for removing sulfides from sewers and crude oil.

  16. Structural effects of naphthalimide-based fluorescent sensor for hydrogen sulfide and imaging in live zebrafish

    Science.gov (United States)

    Choi, Seon-Ae; Park, Chul Soon; Kwon, Oh Seok; Giong, Hoi-Khoanh; Lee, Jeong-Soo; Ha, Tai Hwan; Lee, Chang-Soo

    2016-05-01

    Hydrogen sulfide (H2S) is an important biological messenger, but few biologically-compatible methods are available for its detection in aqueous solution. Herein, we report a highly water-soluble naphthalimide-based fluorescent probe (L1), which is a highly versatile building unit that absorbs and emits at long wavelengths and is selective for hydrogen sulfide over cysteine, glutathione, and other reactive sulfur, nitrogen, and oxygen species in aqueous solution. We describe turn-on fluorescent probes based on azide group reduction on the fluorogenic ‘naphthalene’ moiety to fluorescent amines and intracellular hydrogen sulfide detection without the use of an organic solvent. L1 and L2 were synthetically modified to functional groups with comparable solubility on the N-imide site, showing a marked change in turn-on fluorescent intensity in response to hydrogen sulfide in both PBS buffer and living cells. The probes were readily employed to assess intracellular hydrogen sulfide level changes by imaging endogenous hydrogen sulfide signal in RAW264.7 cells incubated with L1 and L2. Expanding the use of L1 to complex and heterogeneous biological settings, we successfully visualized hydrogen sulfide detection in the yolk, brain and spinal cord of living zebrafish embryos, thereby providing a powerful approach for live imaging for investigating chemical signaling in complex multicellular systems.

  17. In Vitro Antiparasitic and Apoptotic Effects of Antimony Sulfide Nanoparticles on Leishmania infantum

    Directory of Open Access Journals (Sweden)

    Saied Soflaei

    2012-01-01

    Full Text Available Visceral leishmaniasis is one of the most important sever diseases in tropical and subtropical countries. In the present study the effects of antimony sulfide nanoparticles on Leishmania infantum in vitro were evaluated. Antimony sulfide NPs (Sb2S5 were synthesized by biological method from Serratia marcescens bacteria. Then the cytotoxicity effects of different concentrations (5, 10, 25, 50, and 100 μg/mL of this nanoparticle were assessed on promastigote and amastigote stages of L. infantum. MTT method was used for verification results of promastigote assay. Finally, the percentages of apoptotic, necrotic, and viable cells were determined by flow cytometry. The results indicated the positive effectiveness of antimony sulfide NPs on proliferation of promastigote form. The IC50 (50% inhibitory concentration of antimony sulfide NPs on promastigotes was calculated 50 μg/mL. The cytotoxicity effect was dose-dependent means by increasing the concentration of antimony sulfide NPs, the cytotoxicity curve was raised and the viability curve of the parasite dropped simultaneously. Moreover, the IC50 of antimony sulfide NPs on amastigote stage was calculated 25 μg/mL. On the other hand, however, antimony sulfide NPs have a low cytotoxicity effect on uninfected macrophages but it can induce apoptosis in promastigote stage at 3 of 4 concentrations.

  18. Enrichment and immobilization of sulfide removal microbiota applied for environmental biological remediation of aquaculture area.

    Science.gov (United States)

    Zhao, Yang-Guo; Zheng, Yu; Tian, Weijun; Bai, Jie; Feng, Gong; Guo, Liang; Gao, Mengchun

    2016-07-01

    To remove sulfide in the deteriorating aquaculture sediment and water, sulfide-oxidizing microbiota was enriched from Jiaozhou Bay, China, by using sulfide-rich medium. Composition and structure of microbial communities in the enrichments were investigated by 16S rDNA molecular biotechniques. Results showed that microbial community structure continuously shifted and the abundance of sulfate reducing bacteria, i.e., Desulfobacterium, Desulfococcus and Desulfobacca apparently declined. Several halophile genera, Vibrio, Marinobacter, Pseudomonas, Prochlorococcus, Pediococcus and Thiobacillus predominated finally in the microbiota. The enriched microbiota was capable of removing a maximum of 1000 mg/L sulfide within 12 h with 10% inoculum at pH 7.0, 20-30 °C. After immobilized, the microbiota presented excellent resistance to impact and could completely remove 600 mg/L sulfide in 12 h. Moreover, the immobilized microbiota recovered well even recycled for five times. In conclusion, the immobilized sulfide-removing microbiota showed a quite promising application for biological restoring of sulfide-rich aquaculture environment. PMID:27105167

  19. Release and control of hydrogen sulfide during sludge thermal drying

    Energy Technology Data Exchange (ETDEWEB)

    Weng, Huanxin; Dai, Zhixin; Ji, Zhongqiang; Gao, Caixia; Liu, Chongxuan

    2015-04-15

    The release of hydrogen sulfide (H2S) during sludge drying is a major environmental problem because of its toxicity to human health. A series of experiments were performed to investigate the mechanisms and factors controlling the H2S release. Results of this study show that: 1) the biomass and activity of sulfate-reducing bacteria (SRB) in sludge were the major factors controlling the amount of H2S release, 2) the sludge drying temperature had an important effect on both the extent and the timing of H2S release from the sludge, and 3) decreasing sludge pH increased the H2S release. Based on the findings from this study, a new system that integrates sludge drying and H2S gas treatment was developed to reduce the amount of H2S released from sludge treatments.

  20. Changes in Dimethyl Sulfide Oceanic Distribution due to Climate Change

    Energy Technology Data Exchange (ETDEWEB)

    Cameron-Smith, P; Elliott, S; Maltrud, M; Erickson, D; Wingenter, O

    2011-02-16

    Dimethyl sulfide (DMS) is one of the major precursors for aerosols and cloud condensation nuclei in the marine boundary layer over much of the remote ocean. Here they report on coupled climate simulations with a state-of-the-art global ocean biogeochemical model for DMS distribution and fluxes using present-day and future atmospheric CO{sub 2} concentrations. They find changes in zonal averaged DMS flux to the atmosphere of over 150% in the Southern Ocean. This is due to concurrent sea ice changes and ocean ecosystem composition shifts caused by changes in temperature, mixing, nutrient, and light regimes. The largest changes occur in a region already sensitive to climate change, so any resultant local CLAW/Gaia feedback of DMS on clouds, and thus radiative forcing, will be particularly important. A comparison of these results to prior studies shows that increasing model complexity is associted with reduced DMS emissions at the equator and increased emissions at high latitudes.

  1. Endogenous hydrogen sulfide is involved in the pathogenesis of atherosclerosis

    International Nuclear Information System (INIS)

    Atherosclerosis is a chronic, complex, and progressive pathological process in large and medium sized arteries. The exact mechanism of this process remains unclear. Hydrogen sulfide (H2S), a novel gasotransmitter, was confirmed as playing a major role in the pathogenesis of many cardiovascular diseases. It plays a role in vascular smooth muscle cell (VSMC) proliferation and apoptosis, participates in the progress of hyperhomocysteinemia (HHCY), inhibits atherogenic modification of LDL, interferes with vascular calcification, intervenes with platelet function, and there are interactions between H2S and inflammatory processes. The role of H2S in atherosclerotic pathogenesis highlights the mysteries of atherosclerosis and inspires the search for innovative therapeutic strategies. Here, we review the studies to date that have considered the role of H2S in atherosclerosis.

  2. Hydrogen Production from Hydrogen Sulfide in IGCC Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    Elias Stefanakos; Burton Krakow; Jonathan Mbah

    2007-07-31

    IGCC power plants are the cleanest coal-based power generation facilities in the world. Technical improvements are needed to help make them cost competitive. Sulfur recovery is one procedure in which improvement is possible. This project has developed and demonstrated an electrochemical process that could provide such an improvement. IGCC power plants now in operation extract the sulfur from the synthesis gas as hydrogen sulfide. In this project H{sub 2}S has been electrolyzed to yield sulfur and hydrogen (instead of sulfur and water as is the present practice). The value of the byproduct hydrogen makes this process more cost effective. The electrolysis has exploited some recent developments in solid state electrolytes. The proof of principal for the project concept has been accomplished.

  3. Electrodeposited cobalt sulfide hole collecting layer for polymer solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Zampetti, Andrea; De Rossi, Francesca; Brunetti, Francesca; Reale, Andrea; Di Carlo, Aldo; Brown, Thomas M., E-mail: thomas.brown@uniroma2.it [CHOSE (Centre for Hybrid and Organic Solar Energy), Department of Electronic Engineering, University of Rome “Tor Vergata,” Via del Politecnico 1, 00133 Rome (Italy)

    2014-08-11

    In polymer solar cells based on the blend of regioregular poly(3-hexylthiophene) (P3HT) and phenyl-C61-butyric acid methyl ester, the hole collecting layer has to be endowed with its ionization potential close to or greater than that of P3HT (∼5 eV). Conductive polymer blends such as poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) and metal oxides such as vanadium pentoxide (V{sub 2}O{sub 5}) and molybdenum trioxide (MoO{sub 3}) satisfy this requirement and have been the most common materials used so far in bulk heterojunction structures. We report here cobalt sulfide (CoS) to be a promising hole collecting material deposited by convenient and room temperature electrodeposition. By simply tuning the CoS electrodeposition parameters, power conversion efficiencies similar (within 15%) to a reference structure with PEDOT:PSS were obtained.

  4. Endogenous hydrogen sulfide is involved in the pathogenesis of atherosclerosis

    Energy Technology Data Exchange (ETDEWEB)

    Qiao, Wang [Department of Pediatrics, Peking University First Hospital, Beijing 100034 (China); Chaoshu, Tang [Department of Physiology and Pathophysiology, Health Sciences Center, Peking University, Beijing 100034 (China); Key Laboratory of Molecular Cardiovascular Medicine, Ministry of Education (China); Hongfang, Jin, E-mail: jinhongfang51@126.com [Department of Pediatrics, Peking University First Hospital, Beijing 100034 (China); Junbao, Du, E-mail: junbaodu1@126.com [Department of Pediatrics, Peking University First Hospital, Beijing 100034 (China)

    2010-05-28

    Atherosclerosis is a chronic, complex, and progressive pathological process in large and medium sized arteries. The exact mechanism of this process remains unclear. Hydrogen sulfide (H{sub 2}S), a novel gasotransmitter, was confirmed as playing a major role in the pathogenesis of many cardiovascular diseases. It plays a role in vascular smooth muscle cell (VSMC) proliferation and apoptosis, participates in the progress of hyperhomocysteinemia (HHCY), inhibits atherogenic modification of LDL, interferes with vascular calcification, intervenes with platelet function, and there are interactions between H{sub 2}S and inflammatory processes. The role of H{sub 2}S in atherosclerotic pathogenesis highlights the mysteries of atherosclerosis and inspires the search for innovative therapeutic strategies. Here, we review the studies to date that have considered the role of H{sub 2}S in atherosclerosis.

  5. RHEOLOGICAL BEHAVIOR OF POLYPHENYLENE SULFIDE/POLYAMIDE-66 BLENDS

    Institute of Scientific and Technical Information of China (English)

    HOU Canshu; LI Jihong; WANG Yinghan; CHEN Yongrong; WANG Ling

    1996-01-01

    Blends of polyphenylene sulfide (PPS) containing trace amounts of branching and/or cross-linking in chain and Polyamide-66 (PA-66) have been prepared by melt blending. The rheological behavior of PPS/PA-66 blends has been studied by means of capillary rheometer, and compared with PPS. The effects of shear rate, shear stress and temperature on the flow of PPS/PA-66 blends and PPS are discussed. The non-Newtonian indexes and the activation energies of viscous flow are obtained. The results show that the apparent viscosity of PPS/PA-66 blends is not sensitive to shear rate and stress, but decreases with the elevation of temperature. On the contrary, the apparent viscosity of the PPS decreases obviously with the increasing of shear rate and shear stress, but it is increased by the elevation of temperatue.

  6. Lithium sulfide compositions for battery electrolyte and battery electrode coatings

    Science.gov (United States)

    Liang, Chengdu; Liu, Zengcai; Fu, Wunjun; Lin, Zhan; Dudney, Nancy J; Howe, Jane Y; Rondinone, Adam J

    2013-12-03

    Methods of forming lithium-containing electrolytes are provided using wet chemical synthesis. In some examples, the lithium containing electroytes are composed of .beta.-Li.sub.3PS.sub.4 or Li.sub.4P.sub.2S.sub.7. The solid electrolyte may be a core shell material. In one embodiment, the core shell material includes a core of lithium sulfide (Li.sub.2S), a first shell of .beta.-Li.sub.3PS.sub.4 or Li.sub.4P.sub.2S.sub.7, and a second shell including one or .beta.-Li.sub.3PS.sub.4 or Li.sub.4P.sub.2S.sub.7 and carbon. The lithium containing electrolytes may be incorporated into wet cell batteries or solid state batteries.

  7. Hydrogen Sulfide, Oxidative Stress and Periodontal Diseases: A Concise Review.

    Science.gov (United States)

    Greabu, Maria; Totan, Alexandra; Miricescu, Daniela; Radulescu, Radu; Virlan, Justina; Calenic, Bogdan

    2016-01-01

    In the past years, biomedical research has recognized hydrogen sulfide (H₂S) not only as an environmental pollutant but also, along with nitric oxide and carbon monoxide, as an important biological gastransmitter with paramount roles in health and disease. Current research focuses on several aspects of H₂S biology such as the biochemical pathways that generate the compound and its functions in human pathology or drug synthesis that block or stimulate its biosynthesis. The present work addresses the knowledge we have to date on H₂S production and its biological roles in the general human environment with a special focus on the oral cavity and its involvement in the initiation and development of periodontal diseases. PMID:26805896

  8. Hydrogen Sulfide, Oxidative Stress and Periodontal Diseases: A Concise Review

    Directory of Open Access Journals (Sweden)

    Maria Greabu

    2016-01-01

    Full Text Available In the past years, biomedical research has recognized hydrogen sulfide (H2S not only as an environmental pollutant but also, along with nitric oxide and carbon monoxide, as an important biological gastransmitter with paramount roles in health and disease. Current research focuses on several aspects of H2S biology such as the biochemical pathways that generate the compound and its functions in human pathology or drug synthesis that block or stimulate its biosynthesis. The present work addresses the knowledge we have to date on H2S production and its biological roles in the general human environment with a special focus on the oral cavity and its involvement in the initiation and development of periodontal diseases.

  9. Iron (III) sulfide particles produced by a polyol method

    Energy Technology Data Exchange (ETDEWEB)

    Shimizu, Ryo; Kubono, Ippei [Tokyo University of Science (Japan); Kobayashi, Yoshio [The University of Electro-Communications (Japan); Yamada, Yasuhiro, E-mail: yyasu@rs.kagu.tus.ac.jp [Tokyo University of Science (Japan)

    2015-04-15

    Iron(III) sulfide Fe{sub 2}S{sub 3} particles were produced using a polyol method. Although pyrrhotite Fe{sub 1−x}S appeared together with Fe{sub 2}S{sub 3}, the relative yield of Fe{sub 2}S{sub 3} changed when the concentration of reagents in the oleylamine changed. Mössbauer spectra of the particles showed superparamagnetic doublets due to Fe{sub 2}S{sub 3} at 293 K, along with a hyperfine magnetic splitting of H = 24.7 T at 6 K. XRD patterns of the Fe{sub 2}S{sub 3} suggested a structure similar to that of greigite Fe{sub 3}S{sub 4}.

  10. Carbonyl Sulfide Isotopologues: Ultraviolet Absorption Cross Sections and Stratospheric Photolysis

    DEFF Research Database (Denmark)

    Danielache, Sebastian Oscar; Nanbu, Shinkoh; Eskebjerg, Carsten;

    2009-01-01

    Ultraviolet absorption cross sections of the main and substituted carbonyl sulfide isotopologues were calculated using wavepacket dynamics. The calculated absorption cross section of 16O12C32S is in very good agreement with the accepted experimental spectrum between 190 and 250 nm. Relative to 16...... can be explained in terms of the change in the norm of the initial wavepacket. Implications for our understanding of the stratospheric sulfur cycle are discussed.......12C32S, isotopic substitution shows a significant enhancement of the cross section for 16O13C32S, a significant reduction for 18O12C32S and 17O12C32S and almost no change for the sulfur isotopologues 16O12C33S, 16O12C34S, and 16O12C36S. The analysis of the initial wavepackets shows that these changes...

  11. Influence of sulfide on the distribution of higher plants in salt marshes. [Salicornia europaea; Puccinellia maritima; Atriplex patula; Festuca rubra

    Energy Technology Data Exchange (ETDEWEB)

    Ingold, A.; Havill, D.C.

    1984-11-01

    Soluble sulfide in surface (0-5 cm) salt marsh sediments was detectable only on the lower marsh, salt pans and creek beds. On the lower-marsh only Salicornia europaea amongst the vascular plant species present was rooted in sulfide-containing sediments. No significant correlation was observed between soluble sulfide concentration and redox potential in soil samples from the lower-marsh. When eight salt marshes from around the coast of Britain were compared, six had a detectable sulfide concentration in the lower-marsh sediments. Divisive information analysis of the vegetation data from these sites indicated that in all cases the most significant association was between Salicornia europaea and otherwise bare ground. In two marshes where no soluble sulfide could be measured, S. europaea was associated with other plant species rather than bare ground. Monthly observations of plant cover and sulfide concentration in sixteen permanent quadrats on the lower marsh revealed a significant positive correlation between the cover of Salicornia europaea and soil sulfide. In contrast, Puccinellia maritima showed a significant negative correlation with sulfide concentration. In liquid media, the growth of Atriplex patula, Festuca rubra and Puccinellia maritima, was significantly inhibited by sulfide whereas there was no marked effect on that of Salicornia europaea. The results suggest that S. europaea is relatively tolerant of sulfide and is able to establish on areas of the lower marsh from which other species are excluded by the presence of sulfide.

  12. Effect of Sodium Sulfide on Ni-Containing Carbon Monoxide Dehydrogenases

    Energy Technology Data Exchange (ETDEWEB)

    Jian Feng; Paul A. Lindahl

    2004-07-28

    OAK-B135 The structure of the active-site C-cluster in CO dehydrogenase from Carboxythermus hydrogenoformans includes a {mu}{sup 2}-sulfide ion bridged to the Ni and unique Fe, while the same cluster in enzymes from Rhodospirillum rubrum (CODH{sub Rr}) and Moorella thermoacetica (CODH{sub Mt}) lack this ion. This difference was investigated by exploring the effects of sodium sulfide on activity and spectral properties. Sulfide partially inhibited the CO oxidation activity of CODH{sub Rr} and generated a lag prior to steady-state. CODH{sub Mt} was inhibited similarly but without a lag. Adding sulfide to CODH{sub Mt} in the C{sub red1} state caused the g{sub av} = 1.82 EPR signal to decline and new features to appear, including one with g = 1.95, 1.85 and (1.70 or 1.62). Removing sulfide caused the g{sub av} = 1.82 signal to reappear and activity to recover. Sulfide did not affect the g{sub av} = 1.86 signal from the C{sub red2} state. A model was developed in which sulfide binds reversibly to C{sub red1}, inhibiting catalysis. Reducing this adduct causes sulfide to dissociate, C{sub red2} to develop, and activity to recover. Using this model, apparent K{sub I} values are 40 {+-} 10 nM for CODH{sub Rr} and 60 {+-} 30 {micro}M for CODH{sub Mt}. Effects of sulfide are analogous to those of other anions, including the substrate hydroxyl group, suggesting that these ions also bridge the Ni and unique Fe. This proposed arrangement raises the possibility that CO binding labilizes the bridging hydroxyl and increases its nucleophilic tendency towards attacking Ni-bound carbonyl.

  13. Reducing role of sulfides and diamond formation in the Earth's mantle

    Science.gov (United States)

    Palyanov, Yu. N.; Borzdov, Yu. M.; Bataleva, Yu. V.; Sokol, A. G.; Palyanova, G. A.; Kupriyanov, I. N.

    2007-08-01

    Sulfides are abundant inclusions in diamond, but their role in the diamond genesis is still debatable. To address this issue, experimental modeling of natural diamond-forming processes with the participation of sulfides has been performed with the MgCO 3-SiO 2-Al 2O 3-FeS system at 6.3 GPa in the temperature range of 1250-1800 °C, using a multi-anvil high pressure apparatus of the "split-sphere" type. As a result of redox reactions involving carbonate, oxides and sulfide, diamond and/or graphite are produced in association with garnet, orthopyroxene, coesite and sulfides (pyrite, pyrrhotite). Diamond crystals, formed from the carbon of initial carbonate, are found to contain nitrogen impurity with total concentration of approximately 1500 ppm, and defects related to hydrogen impurity. Based on the experimental data and thermodynamic calculations, the processes of the carbonate-oxide-sulfide interaction are reconstructed, revealing the role of sulfides as a reducing agent for CO 2-fluid. It is established that pyrrhotite acts as the reducing agent irrespective of its aggregate state (solid or melt). At temperatures below melting, pyrrhotite is enriched with sulfur and depleted with iron from FeS to Fe 0.85S. At higher temperatures, sulfide melt is enriched with sulfur and crystallizes as pyrite and pyrrhotite during quenching. The medium in which diamond and/or graphite crystallize is a CO 2-dominated fluid containing dissolved carbon, silicates, oxides and sulfides. The investigated processes and mechanisms of diamond crystallization can be considered as a possible model of the diamond formation in sulfide-bearing paragenesis in mantle metasomatism or UHP metamorphism of crustal material.

  14. Feasibility of sulfide control in sewers by reuse of iron rich drinking water treatment sludge.

    Science.gov (United States)

    Sun, Jing; Pikaar, Ilje; Sharma, Keshab Raj; Keller, Jürg; Yuan, Zhiguo

    2015-03-15

    Dosage of iron salt is the most commonly used method for sulfide control in sewer networks but incurs high chemical costs. In this study, we experimentally investigate the feasibility of using iron rich drinking water treatment sludge for sulfide control in sewers. A lab-scale rising main sewer biofilm reactor was used. The sulfide concentration in the effluent decreased from 15.5 to 19.8 mgS/L (without dosing) to below 0.7-2.3 mgS/L at a sludge dosing rate achieving an iron to total dissolved inorganic sulfur molar ratio (Fe:S) of 1:1, with further removal of sulfide possible by prolonging the reaction time. In fact, batch tests revealed an Fe consumption to sulfide removal ratio of 0.5 ± 0.02 (mole:mole), suggesting the possible occurrence of other reactions involving the removal of sulfide. Modelling revealed that the reaction between iron in sludge and sulfide has reaction orders of 0.65 ± 0.01 and 0.77 ± 0.02 with respect to the Fe and sulfide concentrations, respectively. The addition of sludge slightly increased the total chemical oxidation demand (tCOD) concentration (by approximately 12%) as expected, but decreased the soluble chemical oxidation demand (sCOD) concentration and methane formation by 7% and 20%, respectively. Some phosphate removal (13%) was also observed at the sludge dosing rate of 1:1 (Fe:S), which is beneficial to nutrient removal from the wastewater. Overall, this study suggests that dosing iron-rich drinking water sludge to sewers could be an effective strategy for sulfide removal in sewer systems, which would also reduce the sludge disposal costs for drinking water treatment works. However, its potential side-effects on sewer sedimentation and on the wastewater treatment plant effluent remain to be investigated. PMID:25616115

  15. [Investigation of nitrobenzene removal by iron sulfide (FeS)].

    Science.gov (United States)

    Wang, Xia-Lin; Li, Rui-Hua

    2012-12-01

    The nitrobenzene removal performance by iron sulfide was investigated in batch experiments. The effects of different factors were studied. The results showed that the removal efficiency of nitrobenzene was 90% as initial nitrobenzene concentration was 0.96 mmol x L(-1), dosage of FeS was 1.2 g and the reaction time was 180 minutes. Initial nitrobenzene concentration, dosage of FeS, temperature and reused times of FeS had a significant influence on the removal efficiency of nitrobenzene. As the initial nitrobenzene concentration was in range of 0.74 to 1.74 mmol x L(-1), the removal efficiency of nitrobenzene decreased by 4.7% with every 0.1 mmol x L(-1) increasing of initial nitrobenzene concentration. As the dosage of FeS was in the range of 0.3 to 1.5 g, the removal efficiency of nitrobenzene increased by 20% with every 0.3 g increasing of FeS. As the dosage of FeS was 1.8 g, the removal efficiency of nitrobenzene was 100%. In the temperature range of 10 to 25 degrees C, the removal efficiency of nitrobenzene increased by 1.6% with 1 degrees C increasing. As the temperature was 30 degrees C, the removal efficiency of nitrobenzene was 100%. The removal efficiency of nitrobenzene decreased as the reused times of FeS increased. Rotational speed hardly had any influence on the removal efficiency of nitrobenzene. As the rotational speed was in the range of 10 to 80 r x min(-1), the removal efficiency of nitrobenzene was around 75%. The nitrobenzene removal performance by iron sulfide was satisfied in the treatment of simulated chemical industrial wastewater, and after 60 min, the removal efficiency of nitrobenzene was 100%. PMID:23379163

  16. Role of toluene in hydrogen sulfide combustion under Claus condition

    International Nuclear Information System (INIS)

    Highlights: • Examined the role of toluene addition in hydrogen sulfide combustion. • Effect of 0%, 0.5%, 1% and 5% of toluene in H2S gas stream was examined. • Toluene addition triggers production of H2 which provides oxidation competition to H2S. • Increased amount of toluene in H2S gas reduced SO2 and increased asymptotic value of H2S. • Toluene addition enhanced the formation of CO and COS. - Abstract: Experimental investigations on the effect of different amounts of toluene addition to H2S combustion in oxygen under Claus condition (Φ = 3) are presented. Three toluene concentrations of 0.5%, 1% and 5% in H2S are presented and compared with the baseline case of 100% H2S oxygen combustion. Temperature data showed that addition of toluene to H2S gas stream increases the flame temperature because of large heating value associated with toluene. Addition of toluene resulted in the production of H2, which increased with increase in the amounts of toluene addition. Furthermore, increased addition of toluene concentration increased the asymptotic minimum value of hydrogen sulfide due to oxidation competition between the formed H2 and H2S. The results also showed that the presence of CO triggers the formation of COS with toluene addition due to reaction of CO with SO2. The results showed that SO2 mole fraction increased to a maximum value then decayed with distance along the reactor. Addition of toluene increased the rate of SO2 decay. These results have direct impact on sulfur capture in the Claus reactor and its performance

  17. Non-thermal plasma treatment of hydrogen sulfide

    Energy Technology Data Exchange (ETDEWEB)

    Frost, L.J.; Hartvigsen, J.; Elangovan, S. [Ceramatec Inc., Salt Lake City, UT (United States)

    2009-07-01

    This paper described a non-thermal plasma reforming process to treat hydrogen sulfide (H{sub 2}S) in heavy hydrocarbons. H{sub 2}S is present in natural gas, petroleum, and various process gases. It is an unwanted compound that is generally removed using an amine extraction process followed by a Claus process. Ceramatec Inc. has developed a GlidArc plasma reformer to recover some of the hydrogen from the H{sub 2}S. Non-thermal plasma reforming breaks hydrogen sulfide into hydrogen and elemental sulphur. Ceramatec has established the catalytic nature of the non-thermal plasma generated by its GlidArc plasma reformer. This treatment process is still in the laboratory stage, but it offers the possibility of a new method to treat acid gas that will provide an opportunity to recover hydrogen that is currently burned to water during the Claus sulphur removal process. Ceramatec, in conjunction with Albin Czernichowski of ECP in France, has demonstrated the ability to reform a variety of hydrocarbons using the non-thermal plasma catalyzed reaction. The plasma reaction can be initiated in either a partial oxidation or steam reforming mode. Multiple hydrocarbons can be processed by the same unit with only control parameters changing to meet the requirements of the individual hydrocarbons being processed. Although a tested unit did not accomplish complete conversion, some additional options will be tested that are expected to increase the conversion under an existing program operated by the United States Department of Energy. 4 refs., 9 figs.

  18. Production of hydrogen by superadiabatic decomposition of hydrogen sulfide

    Energy Technology Data Exchange (ETDEWEB)

    Slimane, R.B.; Lau, F.S.; Dihu, R. [Gas Technology Inst., Des Plaines, IL (United States); Bingue, J.P.; Saveliev, A.V.; Fridman, A.A.; Kennedy, L.A. [Illinois Univ., Chicago, IL (United States)

    2002-07-01

    It is expected that hydrogen will become the fuel of choice for advanced technologies. Hydrogen is currently used as feedstock in the synthesis of ammonia and methanol, in the desulfurization and hydrocracking at oil refineries, and in the upgrading of hydrocarbon resources such as heavy oil and coal. Hydrogen sulfide (H{sub 2}S) is regarded as a mineral from which both hydrogen and sulfur can be extracted. Since there are large amounts of H{sub 2}S available worldwide, significant research has gone into the development of converting hydrogen sulfide into hydrogen through thermal decomposition. The high temperature required for the reaction, however, makes the approach impractical. This paper presents results of a study using a new approach to overcome the limitations of thermal decomposition. In this newly developed process, operation at very high temperatures is possible and economical through oxidation of part of the H{sub 2}S to provide the energy needed for the decomposition reaction. Partial oxidation is carried out in the presence of an inert, porous, high-capacity medium and the heat exchange results in flame temperatures that exceed the adiabatic flame temperature of the gas mixture. This process is less stringent than the Claus process because of the required feed gas conditioning. SO{sub 2} emissions inevitably form because part of the H{sub 2}S is oxidized to generate heat. However, SO{sub 2} is not expected to form to a significant degree. It was concluded that the product/byproduct separation schemes need to be examined further to have a better idea regarding the cost of hydrogen production from this process. 6 refs., 5 figs.

  19. Productivity-Diversity Relationships from Chemolithoautotrophically Based Sulfidic Karst Systems

    Directory of Open Access Journals (Sweden)

    Porter Megan L.

    2009-01-01

    Full Text Available Although ecosystems thriving in the absence of photosynthetic processes are no longer considered unique phenomena, we haveyet to understand how these ecosystems are energetically sustained via chemosynthesis. Ecosystem energetics were measuredin microbial mats from active sulfidic caves (Movile Cave, Romania; Frasassi Caves, Italy; Lower Kane Cave, Wyoming, USA; andCesspool Cave, Virginia, USA using radiotracer techniques. We also estimated bacterial diversity using 16S rRNA sequences torelate the productivity measurements to the composition of the microbial communities. All of the microbial communities investigatedwere dominated by chemolithoautotrophic productivity, with the highest rates from Movile Cave at 281 g C/m2/yr. Heterotrophicproductivities were at least one order of magnitude less than autotrophy from all of the caves. We generated 414 new 16S rRNAgene sequences that represented 173 operational taxonomic units (OTUs with 99% sequence similarity. Although 13% of theseOTUs were found in more than one cave, the compositions of each community were significantly different from each other (P≤0.001.Autotrophic productivity was positively correlated with overall species richness and with the number of bacterial OTUs affiliated withthe Epsilonproteobacteria, a group known for sulfur cycling and chemolithoautotrophy. Higher rates of autotrophy were also stronglypositively correlated to available metabolic energy sources, and specifically to dissolved sulfide concentrations. The relationship ofautotrophic productivity and heterotrophic cycling rates to bacterial species richness can significantly impact the diversity of highertrophic levels in chemolithoautotrophically-based cave ecosystems, with the systems possessing the highest productivity supportingabundant and diverse macro-invertebrate communities.

  20. Impact of iron sulfide transformation on trichloroethylene degradation

    Energy Technology Data Exchange (ETDEWEB)

    He, Y. Thomas; Wilson, John T.; Wilkin, Richard T. (EPA)

    2010-05-04

    Trichloroethylene (TCE) is one of the most common and persistent groundwater contaminants encountered at hazardous waste sites around the world. A growing body of evidence indicates that iron sulfides play an important role in degrading TCE in natural environments and in engineered systems designed for groundwater cleanup. In this study, we investigate transformation processes of iron sulfides and consequent impacts on TCE degradation using batch experimental techniques, transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray absorption spectroscopy (XAS). Our results show that mackinawite is highly reactive toward TCE and no detectable mineralogical changes were detected during the course of reaction. However, freeze-dried FeS transformed to a mixture of mackinawite and greigite during the freeze drying process, with further mineralogical changes during reaction with TCE to lepidocrocite, goethite and pyrite. Newly formed lepidocrocite is a transient phase, with conversion to goethite over time. TCE transformation kinetics show that freeze-dried FeS is 20-50 times less reactive in degrading TCE than non-freeze-dried FeS, and the TCE degradation rate increases with pH (from 5.4 to 8.3), possibly due to an increase of surface deprotonation or electron transfer at higher pH. Results suggest that freeze drying could cause FeS particle aggregation, decreased surface area and availability of reactive sites; it also could change FeS mineralogy and accelerate mineral transformation. These aspects could contribute to the lower reactivity of freeze-dried FeS toward TCE degradation. Modeling results show that FeS transformation in natural environments depends on specific biogeochemical conditions, and natural FeS transformation may affect mineral reactivity in a similar way as compared to the freeze drying process. Rapid transformation of FeS to FeS{sub 2} could significantly slow down TCE degradation in both natural and engineered systems.

  1. Pyritization processes and greigite formation in the advancing sulfidization front in the Upper Pleistocene sediments of the Black Sea

    DEFF Research Database (Denmark)

    Neretin, LN; Bottcher, ME; Jørgensen, BB;

    2004-01-01

    showed that the process started at the Pleistocene/Holocene transition between 6360 and 11600 yr BP. Our study highlights the importance of anaerobic methane oxidation in generating and maintaining S-enriched layers in marine sediments and has paleoenvironmental implications. Copyright (C) 2004 Elsevier......Pyritization in late Pleistocene sediments of the Black Sea is driven by sulfide formed during anaerobic methane oxidation. A sulfidization front is formed by the opposing gradients of sulfide and dissolved iron. The sulfidization processes are controlled by the diffusion flux of sulfide from above...... and polysulfides, formed from H,S by a reductive dissolution of Fe(Ill)-containing minerals, serve as intermediates to convert iron sulfides into pyrite. In the second process, a "direct" pyrite precipitation occurs through prolonged exposure of iron-containing minerals to dissolved sulfide. Methane-driven sulfate...

  2. Kinetics of Indigenous Nitrate Reducing Sulfide Oxidizing Activity in Microaerophilic Wastewater Biofilms.

    Directory of Open Access Journals (Sweden)

    Desirée Villahermosa

    Full Text Available Nitrate decreases sulfide release in wastewater treatment plants (WWTP, but little is known on how it affects the microzonation and kinetics of related microbial processes within the biofilm. The effect of nitrate addition on these properties for sulfate reduction, sulfide oxidation, and oxygen respiration were studied with the use of microelectrodes in microaerophilic wastewater biofilms. Mass balance calaculations and community composition analysis were also performed. At basal WWTP conditions, the biofilm presented a double-layer system. The upper microaerophilic layer (~300 μm showed low sulfide production (0.31 μmol cm-3 h-1 and oxygen consumption rates (0.01 μmol cm-3 h-1. The anoxic lower layer showed high sulfide production (2.7 μmol cm-3 h-1. Nitrate addition decreased net sulfide production rates, caused by an increase in sulfide oxidation rates (SOR in the upper layer, rather than an inhibition of sulfate reducing bacteria (SRB. This suggests that the indigenous nitrate reducing-sulfide oxidizing bacteria (NR-SOB were immediately activated by nitrate. The functional vertical structure of the biofilm changed to a triple-layer system, where the previously upper sulfide-producing layer in the absence of nitrate split into two new layers: 1 an upper sulfide-consuming layer, whose thickness is probably determined by the nitrate penetration depth within the biofilm, and 2 a middle layer producing sulfide at an even higher rate than in the absence of nitrate in some cases. Below these layers, the lower net sulfide-producing layer remained unaffected. Net SOR varied from 0.05 to 0.72 μmol cm-3 h-1 depending on nitrate and sulfate availability. Addition of low nitrate concentrations likely increased sulfate availability within the biofilm and resulted in an increase of both net sulfate reduction and net sulfide oxidation by overcoming sulfate diffusional limitation from the water phase and the strong coupling between SRB and NR

  3. Kinetics of Indigenous Nitrate Reducing Sulfide Oxidizing Activity in Microaerophilic Wastewater Biofilms

    Science.gov (United States)

    Villahermosa, Desirée; Corzo, Alfonso; Garcia-Robledo, Emilio; González, Juan M.; Papaspyrou, Sokratis

    2016-01-01

    Nitrate decreases sulfide release in wastewater treatment plants (WWTP), but little is known on how it affects the microzonation and kinetics of related microbial processes within the biofilm. The effect of nitrate addition on these properties for sulfate reduction, sulfide oxidation, and oxygen respiration were studied with the use of microelectrodes in microaerophilic wastewater biofilms. Mass balance calaculations and community composition analysis were also performed. At basal WWTP conditions, the biofilm presented a double-layer system. The upper microaerophilic layer (~300 μm) showed low sulfide production (0.31 μmol cm-3 h-1) and oxygen consumption rates (0.01 μmol cm-3 h-1). The anoxic lower layer showed high sulfide production (2.7 μmol cm-3 h-1). Nitrate addition decreased net sulfide production rates, caused by an increase in sulfide oxidation rates (SOR) in the upper layer, rather than an inhibition of sulfate reducing bacteria (SRB). This suggests that the indigenous nitrate reducing-sulfide oxidizing bacteria (NR-SOB) were immediately activated by nitrate. The functional vertical structure of the biofilm changed to a triple-layer system, where the previously upper sulfide-producing layer in the absence of nitrate split into two new layers: 1) an upper sulfide-consuming layer, whose thickness is probably determined by the nitrate penetration depth within the biofilm, and 2) a middle layer producing sulfide at an even higher rate than in the absence of nitrate in some cases. Below these layers, the lower net sulfide-producing layer remained unaffected. Net SOR varied from 0.05 to 0.72 μmol cm-3 h-1 depending on nitrate and sulfate availability. Addition of low nitrate concentrations likely increased sulfate availability within the biofilm and resulted in an increase of both net sulfate reduction and net sulfide oxidation by overcoming sulfate diffusional limitation from the water phase and the strong coupling between SRB and NR-SOB syntrophic

  4. Thermodynamic Modeling of Sulfide Capacity of Na2O-Containing Oxide Melts

    Science.gov (United States)

    Moosavi-Khoonsari, Elmira; Jung, In-Ho

    2016-10-01

    Thermodynamic modeling of the sulfide dissolution in the Na2O-FetO-CaO-MgO-MnO-Al2O3-SiO2 multicomponent slags was performed to investigate the desulfurization of hot metal using Na2O-containing fluxes. The dissolution behavior of sulfur in the melts was modeled using the modified quasi-chemical model in the quadruplet approximation. This model can take into account the short-range ordering and the reciprocal exchange reaction of cations and anions in oxy-sulfide slags. Experimental sulfide capacity data were well predicted from the model with only three model parameters.

  5. First Application of Novel Sulfiding Agent SZ 54 in Domestic Hydrofining Unit

    Institute of Scientific and Technical Information of China (English)

    Pan Maohua

    2006-01-01

    A novel environmentally friendly sulfiding agent SZ 54 was for the first time used for presulfidation of the catalyst in the 2 Mt/a hydrofining unit at Zhenhai Refining and Chemical Company. The application results had shown that the sulfiding agent SZ54 had low smell, high flash point, and safe and environmentally friendly features. The lower decomposition temperature and stepwise chemical decomposition characteristics of this reagent can effectively avoid the reduction of metals and improve sulfur adsorption to meet the needs for sulfidizing the hydrofining catalyst,and is a good reagent worthy of extended application.

  6. Indium sulfide precipitation from hydrochloric acid solutions of calcium and sodium chlorides

    International Nuclear Information System (INIS)

    The effect of precipitation duration, acid concentration, indium complexing with chloride ions on the process of indium sulfide chemical precipitation in hydrochloric acid solutions, precipitate composition and dispersity are studied. It is established that indium sulfide solubility increases in solutions with acid concentration exceeding 0.40-0.45 mol/l. Calcium and indium chloride addition to diluted hydrochloric solutions greatly increases the solubility of indium sulfide. The effect of calcium chloride on In2S3 solubility is higher than that of sodium chloride

  7. Ni-sulfide particles in NaY-zeolite for combined hydrodesulfurization and hydrocracking purposes

    Science.gov (United States)

    de Bont, P. W.; Vissenberg, M. J.; Boellaard, E.; de Beer, V. H. J.; van Veen, J. A. R.; van Santen, R. A.; van der Kraan, A. M.

    1998-12-01

    The influence of physisorbed water on the formation of nickel-sulfide species in a 57Co doped ion exchange type 57Co:NiNaY catalyst is studied by Mössbauer Emission Spectroscopy. The absence or presence of physisorbed water during sulfidation seems to have no influence on the local nickel environment of the formed Ni-sulfide species. This result is confirmed by EXAFS measurements. In spite of the resemblance found in MES and EXAFS a large difference is found for the initial HDS activities, which is explained by the different particle sizes (HREM) found at the outer surface of the zeolite.

  8. Controls on Highly Siderophile Element Concentrations in Martian Basalt: Sulfide Saturation and Under-Saturation

    Science.gov (United States)

    Righter, Kevin

    2009-01-01

    Highly siderophile elements (HSE; Re, Au and the platinum group elements) in shergottites exhibit a wide range from very high, similar to the terrestrial mantle, to very low, similar to sulfide saturated mid ocean ridge basalt (e.g., [1]). This large range has been difficult to explain without good constraints on sulfide saturation or under-saturation [2]. A new model for prediction of sulfide saturation places new constraints on this problem [3]. Shergottite data: For primitive shergottites, pressure and temperature estimates are between 1.2-1.5 GPa, and 1350-1470 C [4]. The range of oxygen fugacities is from FMQ-2 to IW, where the amount of Fe2O3 is low and thus does not have a significant effect on the S saturation values. Finally, the bulk compositions of shergottites have been reported in many recent studies (e.g., [5]). All of this information will be used to test whether shergottites are sulfide saturated [3]. Modeling values and results: The database for HSE partition coefficients has been growing with many new data for silicates and oxides [6-8] to complement a large sulfide database [9- 11]. Combining these data with simple batch melting models allows HSE contents of mantle melts to be estimated for sulfide-bearing vs. sulfide-free mantle. Combining such models with fractional crystallization modeling (e.g., [12]) allows HSE contents of more evolved liquids to be modeled. Most primitive shergottites have high HSE contents (and low S contents) that can be explained by sulfide under-saturated melting of the mantle. An exception is Dhofar 019 which has high S contents and very low HSE contents suggesting sulfide saturation. Most evolved basaltic shergottites have lower S contents than saturation, and intermediate HSE contents that can be explained by olivine, pyroxene, and chromite fractionation. An exception is EET A79001 lithology B, which has very low HSE contents and S contents higher than sulfide saturation values . evidence for sulfide saturation

  9. Arsenic mobilization from sulfidic materials from gold mines in Minas Gerais State

    Directory of Open Access Journals (Sweden)

    Renato Pereira de Andrade

    2008-01-01

    Full Text Available Acid drainage results from exposition of sulfides to the atmosphere. Arsenopyrite is a sulfide that releases arsenic (As to the environment when oxidized. This work evaluated the As mobility in six sulfidic geomaterials from gold mining areas in Minas Gerais State, Brazil. Grained samples (<2 mm were periodically leached with distilled water, during 70 days. Results suggested As sorption onto (hydroxides formed by oxidation of arsenopyrite. Low pH accelerated the acid generation, dissolving Fe oxihydroxides and releasing As. Presence of carbonates decreased oxidation rates and As release. On the other hand, lime added to a partially oxidized sample increased As mobilization.

  10. S-33 constraints on the seawater sulfate contribution in modern seafloor hydrothermal vent sulfides

    Science.gov (United States)

    Ono, Shuhei; Shanks, Wayne C.; Rouxel, O.J.; Rumble, D.

    2007-01-01

    Sulfide sulfur in mid-oceanic ridge hydrothermal vents is derived from leaching of basaltic-sulfide and seawater-derived sulfate that is reduced during high temperature water rock interaction. Conventional sulfur isotope studies, however, are inconclusive about the mass-balance between the two sources because 34S/32S ratios of vent fluid H2S and chimney sulfide minerals may reflect not only the mixing ratio but also isotope exchange between sulfate and sulfide. Here, we show that high-precision analysis of S-33 can provide a unique constraint because isotope mixing and isotope exchange result in different ??33S (?????33S-0.515 ??34S) values of up to 0.04??? even if ??34S values are identical. Detection of such small ??33S differences is technically feasible by using the SF6 dual-inlet mass-spectrometry protocol that has been improved to achieve a precision as good as 0.006??? (2??). Sulfide minerals (marcasite, pyrite, chalcopyrite, and sphalerite) and vent H2S collected from four active seafloor hydrothermal vent sites, East Pacific Rise (EPR) 9-10??N, 13??N, and 21??S and Mid-Atlantic Ridge (MAR) 37??N yield ??33S values ranging from -0.002 to 0.033 and ??34S from -0.5??? to 5.3???. The combined ??34S and ??33S systematics reveal that 73 to 89% of vent sulfides are derived from leaching from basaltic sulfide and only 11 to 27% from seawater-derived sulfate. Pyrite from EPR 13??N and marcasite from MAR 37??N are in isotope disequilibrium not only in ??34S but also in ??33S with respect to associated sphalerite and chalcopyrite, suggesting non-equilibrium sulfur isotope exchange between seawater sulfate and sulfide during pyrite precipitation. Seafloor hydrothermal vent sulfides are characterized by low ??33S values compared with biogenic sulfides, suggesting little or no contribution of sulfide from microbial sulfate reduction into hydrothermal sulfides at sediment-free mid-oceanic ridge systems. We conclude that 33S is an effective new tracer for interplay among

  11. Effect of inoculum and sulfide type on simultaneous hydrogen sulfide removal from biogas and nitrogen removal from swine slurry and microbial mechanism.

    Science.gov (United States)

    Wang, Lan; Wei, Benping; Chen, Ziai; Deng, Liangwei; Song, Li; Wang, Shuang; Zheng, Dan; Liu, Yi; Pu, Xiaodong; Zhang, Yunhong

    2015-12-01

    Four reactors were initiated to study the effect of inoculum and sulfide type on the simultaneous hydrogen sulfide removal from biogas and nitrogen removal from swine slurry (Ssu-Nir) process. Anaerobic sludge, aerobic sludge, and water were used as inocula, and Na2S and biogas were used as a sulfide substrate, respectively. Additionally, 454 pyrosequencing of the 16S rRNA gene was used to explore the bacterial diversity. The results showed that sulfur-oxidizing bacteria (Thiobacillus, 42.2-84.4 %) were dominant in Ssu-Nir process and led to the excellent performance. Aerobic sludge was more suitable for inoculation of the Ssu-Nir process because it is better for rapidly enriching dominant sulfur-oxidizing bacteria (Thiobacillus, 54.4 %), denitrifying sulfur-oxidizing bacteria (40.0 %) and denitrifiers (23.9 %). Lower S(2-) removal efficiency (72.6 %) and NO3 (-) removal efficiency (biogas as a sulfide substrate than when Na2S was used. For the Ssu-Nir process with biogas as the sulfide substrate, limiting H2S absorption caused a high relative abundance of sulfur-oxidizing bacteria, Thiobacillus (84.8 %) and Thiobacillus sayanicus (39.6 %), which in turn led to low relative abundance of denitrifiers (1.6 %) and denitrifying sulfur-oxidizing bacteria (24.4 %), low NO3 (-) removal efficiency, and eventually poor performance.

  12. Sulfide mineralization in ultramafic rocks of the Faryab ophiolite complex, southern Kerman

    Directory of Open Access Journals (Sweden)

    Mohammad Ali Rajabzadeh

    2015-10-01

    Full Text Available Introduction Worldwide, Ni-Cu and PGE magmatic sulfide deposits are confined to the lower parts of stratiform mafic and ultramafic complexes. However, ophiolite mafic and ultramafic complexes have been rarely explored for sulfide deposits despite the fact that they have been extensively explored and exploited for chromite. Sulfide saturation during magmatic evolution is necessary for sulfide mineralization, in which sulfide melts scavenge chalcophile metals from the parent magma and concentrate them in specific lithological zones. The lack of exploration for sulfides in this environment suggests that sulfide saturation is rarely attained in ophiolite-related magmas. Some ophiolites, however, contain sulfide deposits, such as at Acoje in Philippines, and Cliffs in Shetland, U.K. (Evans, 2000; Naldrett, 2004. The Faryab ophiolite complex in southern Kerman Province, the most important mining area for chromite deposits in Iran, is located in the southwest part of the Makran Zone. Evidence of sulfide mineralization has been reported there by some authors (e.g. Rajabzadeh and Moosavinasab, 2013. This paper discusses the genesis of sulfides in the Faryab ophiolite using mineral chemistry of the major mineral phases in different rocks of the ophiolite column in order to determine the possible lithological location of sulfide deposits. Materials and methods Seventy three rock samples from cumulate units were collected from surficial occurrences and drill core. The samples were studied using conventional microscopic methods and the mineralogy confirmed by x-ray diffraction. Electron microprobe analysis was carried out on different mineral phases in order to determine the chemistry of the minerals used in the interpretation of magma evolution in the Faryab ophiolite. Lithologically, the Faryab ophiolite complex is divided into two major parts: the northern part includes magmatic rocks and the southern part is comprised of rocks residual after partial

  13. Preparation of tin sulfide-graphene composites with enhanced lithium storage

    Science.gov (United States)

    Zhu, Junsheng; Wang, Dianlong; Liu, Tiefeng

    2013-10-01

    Tin sulfide-graphene nanocomposites have been synthesized through a facile one-pot solvothermal route. The as-prepared composites are characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Brunauer-Emmett-Teller analysis and elemental analysis. The results indicate that tin sulfide nanoparticles are homogeneously anchored on the surface of graphene. The electrochemical performance of tin sulfide-graphene composites is evaluated by galvanostatic charge-discharge tests and electrochemical impedance spectroscopy. Results show that the composites exhibit enhanced reversible lithium storage properties with high reversible capacity and good cyclic performance. The method presented in this work may provide a facile and economic strategy for the preparation of metal sulfide-graphene composites.

  14. Test of oxidation behavior of sulfide ores at ambient temperature for fire control

    Institute of Scientific and Technical Information of China (English)

    WU Chao; LI Zi-jun; LI Ming; WU Guo-min

    2007-01-01

    The coincidence of relevant factors, e.g. oxygen absorption quantity, weight increment, water soluble iron ions and sulfate ion of sulfide ore samples in the oxidation process, was tested through experiment. Based on a large number of tests for a group sample of sulfide ores from a mine, some important conclusions were obtained. The results obtained by the investigation indicate that there is no general interpretation relative to the oxygen absorption and the formation products of sulfate ion and water soluble iron ions during the oxidation process of sulfide ores at ambient temperature. However, the weight increment of the sulfide ore samples in the oxidation process at ambient temperature has a linear relationship with the quantity of oxygen absorption.

  15. The Synthesis and Characterization of High Molecular Weight Poly(phenylene sulfide/ether)

    Institute of Scientific and Technical Information of China (English)

    Ai Qun GU; Mei Ju XIE; Zi Li YU

    2006-01-01

    Poly(phenylene sulfide/ether) (PPSE) was synthesized from 4,4'-dihydroxydiphenyl sulfide and 4,4'-dichlorodiphenyl sulfide in solution by nucleophilic substitution reaction. The resulting polymer was characterized by viscosity measurement, elemental analysis, FT-IR, 1H NMR, X-ray diffraction and thermal analysis. The results showed that the viscosities of the resulting polymer were above 0.68 dL/g, and the linear chain structure of product was confirmed.PPSE had the same reflex indices as poly(p-phenylene sulfide), an orthorhombic crystalline with unit cell a=0.853, b=0.562, c=1.026nm. The melting temperature, glass transition temperature and initial decomposition temperature were found to be 228℃, 85℃ and 325℃, respectively.The product was soluble in common organic solvents such as NMP, N, N'-dimethylformamide,N, N'-dimethylacetamide and 1,2-dichloroethane.

  16. Sulfide capacities of CaO-CaF2-CaCl2 melts

    Science.gov (United States)

    Simeonov, Simeon; Sakai, Toshihiko; Maeda, Masafumi

    1992-06-01

    The sulfide capacityC_{s^{2 - } } = ({text{pct S}}^{{text{2 - }}} )(p_{{text{O}}_{text{2}} } /p_{{text{S}}_{text{2}} } )^{1/2} ) of CaO-CaF2-CaCl2 slag was determined at temperatures from 1000 °C to 1300 °C by equilibrating molten slag, molten silver, and CO-CO2-Ar gas mixture. The sulfide capacity increases with replacing CaCl2 by CaF2 in slags of constant CaO contents. The sulfide capacity also increases with increasing temperature as well as with increasing CaO content at a constant ratio of CaF2/CaCl2 of unity. A linear relationship between the sulfide capacity and carbonate capacity in literature was observed on a logarithmic scale.

  17. Sulfidation of 310 stainless steel at sulfur potentials encountered in coal conversion systems

    Science.gov (United States)

    Rao, D. B.; Nelson, H. G.

    1976-01-01

    The sulfidation of SAE 310 stainless steel was carried out in gas mixtures of hydrogen and hydrogen sulfide over a range of sulfur potentials anticipated in advanced coal gasification processes. The kinetics, composition, and morphology of sulfide scale formation were studied at a fixed temperature of 1065 K over a range of sulfur potentials from .00015N/sqm to 900N/sqm. At all sulfur potentials investigated, the sulfide scales were found to be multilayered. The relative thickness of the individual layers as well as the composition was found to depend on the sulfur potential. The reaction was found to obey the parabolic rate law after an initial transient period. Considerably longer transient periods were found to be due to unsteady state conditions resulting from compositional variations in the spinel layer.

  18. Inhibition of sulfide generation by dosing formaldehyde and its derivatives in sewage under anaerobic conditions.

    Science.gov (United States)

    Zhang, L; Mendoza, L; Marzorati, M; Verstraete, W

    2008-01-01

    Hydrogen sulfide emission in sewers is associated with toxicity, corrosion, odor nuisance and a lot of costs. The possibility to inhibit sulfide generation by formaldehyde and its derivatives (paraformaldehyde and urea formaldehyde) has been evaluated under anaerobic conditions. The impact of formaldehyde on an activated sludge system and an appraisal of the economic aspects are also presented. The optimum dosage to inhibit sulfide generation in sewage was 12-19 mg L(-1) formaldehyde. The dosages of 32 mg L(-1) paraformaldehyde or 100 mg L(-1) urea formaldehyde were not capable of inhibiting sulfide generation in sewage. The impact of 19 mg L(-1) formaldehyde on activated sludge system was negligible in terms of COD removal, nitrification rate and oxygen uptake rate.

  19. Personal Review: Sources of sulfide in waste streams and current biotechnologies for its removal

    Institute of Scientific and Technical Information of China (English)

    MAHMOOD Qaisar; ZHENG Ping; CAI Jing; HAYAT Yousaf; HASSAN Muhammad Jaffar; WU Dong-lei; HU Bao-lan

    2007-01-01

    Sulfide-containing waste streams are generated by a number of industries. It is emitted into the environment as dissolved sulfide (S2- and HS-) in wastewaters and as H2S in waste gases. Due to its corrosive nature, biological hydrogen sulfide removal processes are being investigated to overcome the chemical and disposal costs associated with existing chemically based removal processes. The nitrogen and sulfur metabolism interacts at various levels of the wastewater treatment process. Hence, the sulfur cycle offers possibilities to integrate nitrogen removal in the treatment process, which needs to be further optimized by appropriate design of the reactor configuration, optimization of performance parameters, retention of biomass and optimization of biomass growth. The present paper reviews the biotechnological advances to remove sulfides from various environments.

  20. Effect of cathode electron acceptors on simultaneous anaerobic sulfide and nitrate removal in microbial fuel cell.

    Science.gov (United States)

    Cai, Jing; Zheng, Ping; Mahmood, Qaisar

    2016-01-01

    The current investigation reports the effect of cathode electron acceptors on simultaneous sulfide and nitrate removal in two-chamber microbial fuel cells (MFCs). Potassium permanganate and potassium ferricyanide were common cathode electron acceptors and evaluated for substrate removal and electricity generation. The abiotic MFCs produced electricity through spontaneous electrochemical oxidation of sulfide. In comparison with abiotic MFC, the biotic MFC showed better ability for simultaneous nitrate and sulfide removal along with electricity generation. Keeping external resistance of 1,000 Ω, both MFCs showed good capacities for substrate removal where nitrogen and sulfate were the main end products. The steady voltage with potassium permanganate electrodes was nearly twice that of with potassium ferricyanide. Cyclic voltammetry curves confirmed that the potassium permanganate had higher catalytic activity than potassium ferricyanide. The potassium permanganate may be a suitable choice as cathode electron acceptor for enhanced electricity generation during simultaneous treatment of sulfide and nitrate in MFCs. PMID:26901739

  1. Molecular Simulation Study on Interaction of Thiophene Sulfides with Transition Metals

    Institute of Scientific and Technical Information of China (English)

    Liu Yujian; Long Jun; Zhou Han; Zhu Yuxia; Da Zhijian

    2003-01-01

    The computer molecular simulation technique was applied to study the chemisorption of thiophene and tetramethylthiophene as the model sulfides on the simple oxides and complex oxides of some transition metals as the catalytic materials. The study disclosed that the thiophene sulfides could enter into chemisorption with metal oxides such as VO, ZnO, NiO and Zn-Al-spinel. This interaction could lead to thiophene molecular structure deformation to be in an activated adsorption state, which could help to promote the conversion of thiophene sulfides in the course of catalytic cracking. The VO with a valence of 2 could provide relatively strong selective adsorption sites for the conversion of thiophene sulfides to apparently transform the molecular structures and electron cloud states of such heterocyclic sulfur compounds such as thiophene and tetramethylthiophene into an activated adsorption state. The effect of this interaction was more pronounced with respect to tetramethylthiophene.

  2. Dynamics of wood fall colonization in relation to sulfide concentration in a mangrove swamp.

    Science.gov (United States)

    Laurent, Mélina C Z; Le Bris, Nadine; Gaill, Françoise; Gros, Olivier

    2013-01-01

    Wood debris are an important component of mangrove marine environments. Current knowledge of the ecological role of wood falls is limited by the absence of information on metazoan colonization processes over time. The aim of this study was to provide insights to their temporal dynamics of wood eukaryotic colonization from a shallow water experiment in a mangrove swamp. Combined in situ chemical monitoring and biological surveys revealed that the succession of colonizers in the mangrove swamp relates with the rapid evolution of sulfide concentration on the wood surface. Sulfide-tolerant species are among the first colonizers and dominate over several weeks when the sulfide content is at its maximum, followed by less tolerant opportunistic species when sulfide decreases. This study supports the idea that woody debris can sustain chemosynthetic symbioses over short time-scale in tropical shallow waters. PMID:23623161

  3. Harvesting biohydrogen from cellobiose from sulfide or nitrite-containing wastewaters using Clostridium sp. R1.

    Science.gov (United States)

    Ho, Kuo-Ling; Lee, Duu-Jong

    2011-09-01

    Harvesting biohydrogen from inhibiting wastewaters is of practical interest since the toxicity of compounds in a wastewater stream commonly prevents the bioenergy content being recovered. The isolated Clostridium sp. R1 is utilized to degrade cellobiose in sulfide or nitrite-containing medium for biohydrogen production. The strain can effectively degrade cellobiose free of severe inhibitory effects at up to 200 mgl(-1) sulfide or to 5 mgl(-1) nitrite, yielding hydrogen at >2.0 mol H2 mol(-1) cellobiose. Principal metabolites of cellobiose fermentation are acetate and butyrate, with the concentration of the former increases with increasing sulfide and nitrite concentrations. The isolated strain can yield hydrogen from cellobiose in sulfide-laden wastewaters. However, the present of nitrite significantly limit the efficiency of the biohydrogen harvesting process.

  4. Activation of AhR-mediated toxicity pathway by emerging pollutants polychlorinated diphenyl sulfides

    Science.gov (United States)

    Polychlorinated diphenyl sulfides (PCDPSs) are a group of environmental pollutants for which limited toxicological information is available. This study tested the hypothesis that PCDPSs could activate the mammalian aryl hydrocarbon receptor (AhR) mediated toxicity pathways. Eight...

  5. Sulfide Composition and Melt Stability Field in the Earth's Upper Mantle

    Science.gov (United States)

    Zhang, Z.; Hirschmann, M. M.

    2015-12-01

    In the Earth's upper mantle, sulfur occurs chiefly as (Fe, Ni)xS minerals and melts with near-monosulfide stoichiometries. These could have substantial influence on geochemical and geophysical properties of the Earth's interior. For example, sulfide mineral and melts are the major carriers of chalcophile and platinum group elements (PGEs) and sulfide melts are potentially responsible for mantle geophysical anomalies, as their physical properties (higher density, surface tension, electrical conductivity and lower melting points) differ greatly from those of silicates. Sulfide melts are a potential sink for reduced mantle carbon and perhaps be associated with carbon transport, including diamond precipitation. Sulfides may be molten in large parts of the mantle, but this is determined in part by sulfide composition, which is in turn a product of Fe-Ni exchange with olivine and of the effect of sulfur, oxygen, and carbon fugacities on metal/anion ratios of melts. Melting experiments define the monosulfide (Fe0.35Ni0.12Cu0.01S0.52) solidus from 1-8 GPa at carbon-free and graphite saturated conditions. The resulting carbon-free solidus is below the mantle adiabat to depths of at least 300 km, but does not indicate sulfide melting in continental lithosphere. In contrast, the graphite saturated solidus indicates melting in the lithosphere at 6-7 GPa (~200 km), close to the source conditions typical of diamond formation. To determine the composition of sulfide equilibrated with olivine, we performed experiments on monosulfide-olivine (crushed powders from San Carlos single crystal) under 2 GPa, 1400 ◦C. Our preliminary results suggests that Fe-Ni distribution coefficients KD, defined by (Ni/Fe)sulfide/(Ni/Fe)olivine, have significantly lower values than those determined previously at one atmosphere (Doyle and Naldrett 1987; Fleet and MacRae 1987; Gaetani and Grove 1997). This indicates that sulfide equilibrated with olivine in the mantle is richer in Fe than former

  6. Sulfide-driven autotrophic denitrification significantly reduces N2O emissions.

    Science.gov (United States)

    Yang, Weiming; Zhao, Qing; Lu, Hui; Ding, Zhi; Meng, Liao; Chen, Guang-Hao

    2016-03-01

    The Sulfate reduction-Autotrophic denitrification-Nitrification Integrated (SANI) process build on anaerobic carbon conversion through biological sulfate reduction and autotrophic denitrification by using the sulfide byproduct from the previous reaction. This study confirmed extra decreases in N2O emissions from the sulfide-driven autotrophic denitrification by investigating N2O reduction, accumulation, and emission in the presence of different sulfide/nitrate (S/N) mass ratios at pH 7 in a long-term laboratory-scale granular sludge autotrophic denitrification reactor. The N2O reduction rate was linearly proportional to the sulfide concentration, which confirmed that no sulfide inhibition of N2O reductase occurred. At S/N = 5.0 g-S/g-N, this rate resulted by sulfide-driven autotrophic denitrifying granular sludge (average granule size = 701 μm) was 27.7 mg-N/g-VSS/h (i.e., 2 and 4 times greater than those at 2.5 and 0.8 g-S/g-N, respectively). Sulfide actually stimulates rather than inhibits N2O reduction no matter what granule size of sulfide-driven autotrophic denitrifying sludge engaged. The accumulations of N2O, nitrite and free nitrous acid (FNA) with average granule size 701 μm of sulfide-driven autotrophic denitrifying granular sludge engaged at S/N = 5.0 g-S/g-N were 4.7%, 11.4% and 4.2% relative to those at 3.0 g-S/g-N, respectively. The accumulation of FNA can inhibit N2O reduction and increase N2O accumulation during sulfide-driven autotrophic denitrification. In addition, the N2O gas emission level from the reactor significantly increased from 14.1 ± 0.5 ppmv (0.002% of the N load) to 3707.4 ± 36.7 ppmv (0.405% of the N load) as the S/N mass ratio in the influent decreased from 2.1 to 1.4 g-S/g-N over the course of the 120-day continuous monitoring period. Sulfide-driven autotrophic denitrification may significantly reduce greenhouse gas emissions from biological nutrient removal when sulfur conversion processes are applied. PMID

  7. Development of novel and sensitive methods for the determination of sulfide in aqueous samples by hydrogen sulfide generation-inductively coupled plasma-atomic emission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Colon, M. [Department of Chemistry, University of Girona, Campus Montilivi, 17071 Girona (Spain); Departamento de Quimica Analitica, Nutricion y Bromatologia, University of Alicante, 03080 Alicante (Spain); Todoli, J.L. [Departamento de Quimica Analitica, Nutricion y Bromatologia, University of Alicante, 03080 Alicante (Spain); Hidalgo, M. [Department of Chemistry, University of Girona, Campus Montilivi, 17071 Girona (Spain); Iglesias, M. [Department of Chemistry, University of Girona, Campus Montilivi, 17071 Girona (Spain)], E-mail: monica.iglesias@udg.es

    2008-02-25

    Two new, simple and accurate methods for the determination of sulfide (S{sup 2-}) at low levels ({mu}g L{sup -1}) in aqueous samples were developed. The generation of hydrogen sulfide (H{sub 2}S) took place in a coil where sulfide reacted with hydrochloric acid. The resulting H{sub 2}S was then introduced as a vapor into an inductively coupled plasma-atomic emission spectrometer (ICP-AES) and sulfur emission intensity was measured at 180.669 nm. In comparison to when aqueous sulfide was introduced, the introduction of sulfur as H{sub 2}S enhanced the sulfur signal emission. By setting a gas separator at the end of the reaction coil, reduced sulfur species in the form of H{sub 2}S were removed from the water matrix, thus, interferences could be avoided. Alternatively, the gas separator was replaced by a nebulizer/spray chamber combination to introduce the sample matrix and reagents into the plasma. This methodology allowed the determination of both sulfide and sulfate in aqueous samples. For both methods the linear response was found to range from 5 {mu}g L{sup -1} to 25 mg L{sup -1} of sulfide. Detection limits of 5 {mu}g L{sup -1} and 6 {mu}g L{sup -1} were obtained with and without the gas separator, respectively. These new methods were evaluated by comparison to the standard potentiometric method and were successfully applied to the analysis of reduced sulfur species in environmental waters.

  8. Metal sulfide and rare-earth phosphate nanostructures and methods of making same

    Science.gov (United States)

    Wong, Stanislaus; Zhang, Fen

    2014-05-13

    The present invention provides a method of producing a crystalline metal sulfide nanostructure. The metal is a transitional metal or a Group IV metal. In the method, a porous membrane is placed between a metal precursor solution and a sulfur precursor solution. The metal cations of the metal precursor solution and sulfur ions of the sulfur precursor solution react, thereby producing a crystalline metal sulfide nanostructure.

  9. Sulfide capacities of Na2O-SiO2 melts

    Science.gov (United States)

    Reddy, R. G.; Zhao, W.

    1995-10-01

    Sulfide capacities of Na2O-SiO2 melts at 1473, 1523, 1573, 1623, and 1673 K were calculated a priori using the revised Reddy Blander model. An expression for C S in the composition range of 0≤ X SiO 2sulfide capacities of slags are found to be directly related to two independent quantities: the equilibrium constant K and the activity of the base oxide.

  10. Removal of Sulfide and COD from a Crude Oil Wastewater Model by Aluminum and Iron Electrocoagulation

    Directory of Open Access Journals (Sweden)

    K. I. Dermentzis

    2016-04-01

    Full Text Available The treatment of petroleum wastewater was studied using the electrocoagulation process with aluminum and iron electrodes aiming to simultaneous removal of sulfide and COD. All affecting parameters, such as solution pH, applied current density, time of electroprocessing, electrode material and addition of surfactant, were investigated. Sulfide was rapidly and effectively removed using iron electrodes. The removal of COD was effectively effectively enhanced by performing the electrocoagulation process after addition of the surfactant polyethylene glycol oleate.

  11. Global Neoproterozoic (Sturtian) post-glacial sulfide-sulfur isotope anomaly recognised in Namibia

    Science.gov (United States)

    Gorjan, Paul; Walter, Malcolm R.; Swart, Roger

    2003-02-01

    The Neoproterozoic Earth experienced at least two, probably global, glaciations. Each glaciation was superceded by deposition of a layer of carbonate ('cap-carbonate') that has a distinctive lithology and depletion in 13C ( δ13C carbonate ˜ -5‰). The ˜700 Ma Sturtian glaciation is followed by deposition of a cap-carbonate and post-glacial succession which contain bacterially produced sulfides extremely enriched in 34S (average δ34S sulfide ˜ +30‰) with maximum values up to +60‰. This level of 34S enrichment in sulfides is unique to the Sturtian post-glacial succession and recognised in Australia, Canada, and China. In the Neoproterozoic of the Nama Basin, Namibia, the Gobabis Member is the basal unit of the Court Formation, which overlies the glacial Blaubeker Formation. δ13C carbonate analyses from the Gobabis Member range from -5.2 to -2.2‰ (average = -3.7‰; n = 10). δ34S sulfide ranges from +16.1 to +61.1‰ (average = +37.6‰; n = 8). These results are consistent with a Sturtian age for the Blaubeker Formation and overlying Gobabis Member, which have previously been interpreted as Sturtian. The sulfur isotopic results are comparable with δ34S sulfide in Sturtian post-glacial units of Australia, Canada and China. This adds to the evidence for correlation of the Blaubeker Formation with Sturtian glaciations on other continents. The cause of such elevated δ34S sulfide is enigmatic. Geochemical evidence suggests the sulfide was not formed from low sulfate waters nor in euxinic conditions, which discounts any known modern analogue. 34S enrichment in sulfides is therefore postulated to be caused by enrichment of 34S in contemporaneous seawater ( δ34S sulfate up to +60‰?). The rise in seawater δ34S sulfate is considered to be the result of intense bacterial sulfate reduction in an anoxic ocean during the Sturtian glaciation.

  12. Biological removal of air loaded with a hydrogen sulfide and ammonia mixture

    Institute of Scientific and Technical Information of China (English)

    CHEN Ying-xu; YIN Jun; FANG Shi

    2004-01-01

    The nuisance impact of air pollutant emissions from wastewater pumping stations is a major issue of concern to China. Hydrogen sulfide and ammonia are commonly the primary odor and are important targets for removal. An alternative control technology, biofiltration, was studied. The aim of this study is to investigate the potential of unit systems packed with compost in terms of ammonia and hydrogen sulfide emissions treatment, and to establish optimal operating conditions for a full-scale conceptual design. The laboratory scale biofilter packed with compost was continuously supplied with hydrogen sulfide and ammonia gas mixtures. A volumetric load of less than 150 gH2S/(m3· d) and 230 gNH3/(m3· d) was applied for about fifteen weeks. Hydrogen sulfide and ammonia elimination occurred in the biofilter simultaneously. The removal efficiency, removal capacity and removal kinetics in the biofilter were studied. The hydrogen sulfide removal efficiency reached was very high above 99%, and ammonia removal efficiency was about 80%. Hydrogen sulfide was oxidized into sulphate. The ammonia oxidation products were nitrite and nitrate. Ammonia in the biofilter was mainly removed by adsorption onto the carrier material and by absorption into the water fraction of the carrier material. High percentages of hydrogen sulfide or ammonia were oxidized in the first section of the column. Through kinetics analysis, the presence of amrronia did not hinder the hydrogen sulfide removal. According to the relationship between pressure drop and gas velocity for the biofilter and Reynolds number, non-Darcy flow can be assumed to represent the flow in the medium.

  13. Ab Initio Investigation of Methanthiol and Dimethyl Sulfide Adsorption on Zeolite

    Institute of Scientific and Technical Information of China (English)

    Lü Renqing

    2006-01-01

    The Hartree-Fock and cluster model methods have been employed to investigate interactions of methanthiol or dimethyl sulfide on zeolites. Molecular complexes formed by adsorption of methanthiol on silanol H3SiOSi(OH)2OSiH3 with five coordination forms and dimethyl sulfide on silanol H3SiOSi(OH)2OSiH3 with four coordination forms, and Br(o)nsted acid sites of bridging hydroxyl H3Si(OH)Al(OH)2OSiH3 entering into interactions with methanthiol or dimethyl sulfide have been investigated. Full optimization and frequency analysis of all cluster models have been carried out using the Hartree-Fock method at 6-31 +G** basis set level for hydrogen, silicon, aluminum, oxygen, carbon, and sulfur atoms. The structures and energy changes of different coordination forms derived from methanthiol and H3Si(OH)Al(OH)2OSiH3, dimethyl sulfide and H3Si(OH)Al(OH)2OSiH3, methanthiol and H3SiOSi(OH)2OSiH3, dimethyl sulfide and H3SiOSi(OH)2OSiH3 complexes have been comparatively studied. The calculated results showed that the nature of interactions leading to the formation of the bridging hydroxyl-methanthiol, silanol-methanthiol,bridging hydroxyl-dimethyl sulfide, silanol-dimethyl sulfide complexes was governed by the Van der Waals force as confirmed by a small change in geometric structures and properties. Methanthiol and dimethyl sulfide molecules were adsorbed on bridging hydroxyl group prior to silanol group as evidenced by the heat of adsorption, and the protonization of methanthiol adsorption on bridging hydroxyl model, which was supposed in the literature, was not found.

  14. Core-Shell Nanopillar Array Solar Cells using Cadmium Sulfide Coating on Indium Phosphide Nanopillars

    OpenAIRE

    Tu, Bor-An Clayton

    2013-01-01

    This thesis presents a new strategy to fabricate nanostructured indium phosphide and cadmium sulfide photovoltaics. The cells are formed by chemical bath deposition (electroless deposition) of cadmium sulfide onto indium phosphide nanopillar arrays grown by selective-area metalorganic chemical vapor deposition. Characterizations through electrical and optical measurements show that the devices consisting of p-InP core and CdS shell have a conversion efficiency, open circuit voltage, short cir...

  15. Nanoscale Zero-Valent Iron for Sulfide Removal from Digested Piggery Wastewater

    Directory of Open Access Journals (Sweden)

    Sheng-Hsun Chaung

    2014-01-01

    Full Text Available The removal of dissolved sulfides in water and wastewater by nanoscale zero-valent iron (nZVI was examined in the study. Both laboratory batch studies and a pilot test in a 50,000-pig farm were conducted. Laboratory studies indicated that the sulfide removal with nZVI was a function of pH where an increase in pH decreased removal rates. The pH effect on the sulfide removal with nZVI is attributed to the formation of FeS through the precipitation of Fe(II and sulfide. The saturated adsorption capacities determined by the Langmuir model were 821.2, 486.3, and 359.7 mg/g at pH values 4, 7, and 12, respectively, for nZVI, largely higher than conventional adsorbents such as activated carbon and impregnated activated carbon. The surface characterization of sulfide-laden nZVI using XPS and TGA indicated the formation of iron sulfide, disulfide, and polysulfide that may account for the high adsorption capacity of nZVI towards sulfide. The pilot study showed the effectiveness of nZVI for sulfide removal; however, the adsorption capacity is almost 50 times less than that determined in the laboratory studies during the testing period of 30 d. The complexity of digested wastewater constituents may limit the effectiveness of nZVI. Microbial analysis suggested that the impact of nZVI on the change of microbial species distribution was relatively noticeable after the addition of nZVI.

  16. Why does the Conductivity of a Nickel Catalyst Increase during Sulfidation? An Exemplary Study Using an In Operando Sensor Device

    Directory of Open Access Journals (Sweden)

    Peter Fremerey

    2015-10-01

    Full Text Available In order to study the sulfidation of a catalyst fixed bed, an in operando single pellet sensor was designed. A catalyst pellet from the fixed bed was electrically contacted and its electrical response was correlated with the catalyst behavior. For the sulfidation tests, a nickel catalyst was used and was sulfidized with H2S. This catalyst had a very low conductivity in the reduced state. During sulfidation, the conductivity of the catalyst increased by decades. A reaction from nickel to nickel sulfide occurred. This conductivity increase by decades during sulfidation had not been expected since both nickel and nickel sulfides behave metallic. Only by assuming a percolation phenomenon that originates from a volume increase of the nickel contacts when reacting to nickel sulfides, this effect can be explained. This assumption was supported by sulfidation tests with differently nickel loaded catalysts and it was quantitatively estimated by a general effective media theory. The single pellet sensor device for in operando investigation of sulfidation can be considered as a valuable tool to get further insights into catalysts under reaction conditions.

  17. Why does the Conductivity of a Nickel Catalyst Increase during Sulfidation? An Exemplary Study Using an In Operando Sensor Device.

    Science.gov (United States)

    Fremerey, Peter; Jess, Andreas; Moos, Ralf

    2015-01-01

    In order to study the sulfidation of a catalyst fixed bed, an in operando single pellet sensor was designed. A catalyst pellet from the fixed bed was electrically contacted and its electrical response was correlated with the catalyst behavior. For the sulfidation tests, a nickel catalyst was used and was sulfidized with H₂S. This catalyst had a very low conductivity in the reduced state. During sulfidation, the conductivity of the catalyst increased by decades. A reaction from nickel to nickel sulfide occurred. This conductivity increase by decades during sulfidation had not been expected since both nickel and nickel sulfides behave metallic. Only by assuming a percolation phenomenon that originates from a volume increase of the nickel contacts when reacting to nickel sulfides, this effect can be explained. This assumption was supported by sulfidation tests with differently nickel loaded catalysts and it was quantitatively estimated by a general effective media theory. The single pellet sensor device for in operando investigation of sulfidation can be considered as a valuable tool to get further insights into catalysts under reaction conditions. PMID:26512669

  18. Kinetics and correlation analysis of reactivity in the oxidation of organic sulfides by butyltriphenylphosphonium dichromate

    Indian Academy of Sciences (India)

    K M Dilsha; Seema Kothari

    2009-03-01

    The oxidation of a number of monosubstituted aryl methyl, alkyl phenyl, dialkyl, and diphenyl sulfides by butyltriphenylphosphonium dichromate (BTPPD), to the corresponding sulfoxides, is first order with respect to BTPPD and is second order with respect to sulfide. The reaction is catalysed by hydrogen ions and the dependence is of second order. The oxidation of meta- and para-substituted aryl methyl sulfides correlated best in terms of Hammett equation, the reactions exhibited negative polar reaction constant. The ortho-substituted compounds correlated best in terms of Charton’s triparametric equation with negative polar constant and a small degree of steric hindrance. The oxidation of alkyl phenyl sulfides exhibited a good correlation in terms of Pavelich-Taft equation confirming that the electron-donating power of the alkyl group increases the rate, however, the reactivity is not markedly controlled by the bulkiness of the alkyl group. The rates of oxidation of sulfides were determined in nineteen organic solvents. An analysis of the solvent effect by multi-parametric equations indicated the relatively greater importance of the cation-solvating power of the solvents. A mechanism involving a single-step electrophilic oxygen transfer from BTPPD to the sulfide leading to polar transition state has been proposed.

  19. Microbial communities and arsenic biogeochemistry at the outflow of an alkaline sulfide-rich hot spring

    Science.gov (United States)

    Jiang, Zhou; Li, Ping; van Nostrand, Joy D.; Zhang, Ping; Zhou, Jizhong; Wang, Yanhong; Dai, Xinyue; Zhang, Rui; Jiang, Dawei; Wang, Yanxin

    2016-04-01

    Alkaline sulfide-rich hot springs provide a unique environment for microbial community and arsenic (As) biogeochemistry. In this study, a representative alkaline sulfide-rich hot spring, Zimeiquan in the Tengchong geothermal area, was chosen to study arsenic geochemistry and microbial community using Illumina MiSeq sequencing. Over 0.26 million 16S rRNA sequence reads were obtained from 5-paired parallel water and sediment samples along the hot spring’s outflow channel. High ratios of As(V)/AsSum (total combined arsenate and arsenite concentrations) (0.59-0.78), coupled with high sulfide (up to 5.87 mg/L), were present in the hot spring’s pools, which suggested As(III) oxidation occurred. Along the outflow channel, AsSum increased from 5.45 to 13.86 μmol/L, and the combined sulfide and sulfate concentrations increased from 292.02 to 364.28 μmol/L. These increases were primarily attributed to thioarsenic transformation. Temperature, sulfide, As and dissolved oxygen significantly shaped the microbial communities between not only the pools and downstream samples, but also water and sediment samples. Results implied that the upstream Thermocrinis was responsible for the transformation of thioarsenic to As(III) and the downstream Thermus contributed to derived As(III) oxidation. This study improves our understanding of microbially-mediated As transformation in alkaline sulfide-rich hot springs.

  20. Antagonism of Acute Sulfide Poisoning in Mice by Nitrite Anion without Methemoglobinemia.

    Science.gov (United States)

    Cronican, Andrea A; Frawley, Kristin L; Ahmed, Humza; Pearce, Linda L; Peterson, Jim

    2015-07-20

    There are currently no FDA-approved antidotes for H2S/sulfide intoxication. Sodium nitrite, if given prophylactically to Swiss Webster mice, was shown to be highly protective against the acute toxic effects of sodium hydrosulfide (∼LD40 dose) with both agents administered by intraperitoneal injections. However, sodium nitrite administered after the toxicant dose did not detectably ameliorate sulfide toxicity in this fast-delivery, single-shot experimental paradigm. Nitrite anion was shown to rapidly produce NO in the bloodstream, as judged by the appearance of EPR signals attributable to nitrosylhemoglobin and methemoglobin, together amounting to less than 5% of the total hemoglobin present. Sulfide-intoxicated mice were neither helped by the supplemental administration of 100% oxygen nor were there any detrimental effects. Compared to cyanide-intoxicated mice, animals surviving sulfide intoxication exhibited very short knockdown times (if any) and full recovery was extremely fast (∼15 min) irrespective of whether sodium nitrite was administered. Behavioral experiments testing the ability of mice to maintain balance on a rotating cylinder showed no motor impairment up to 24 h post sulfide exposure. It is argued that antagonism of sulfide inhibition of cytochrome c oxidase by NO is the crucial antidotal activity of nitrite rather than formation of methemoglobin.

  1. Correlations among factors of sulfide ores in oxidation process at ambient temperature

    Institute of Scientific and Technical Information of China (English)

    吴超; 李孜军; 周勃

    2004-01-01

    Spontaneous combustion is one of the serious problems in the mining of sulfide ore deposits. The relevant factors, e. G. Oxygen absorption quantity, mass increase, contents of water soluble iron ions and sulfate ion of sulfide ore samples in the oxidation process were investigated both in theory and experiment. The results from the investigation show that there is no general interpretation relation among the oxygen absorption quantity, the contents of sulfate ion and water soluble iron ions during the oxidation process of sulfide ores at ambient temperature.However, there is a linear relationship between the mass increase of the sulfide ore samples in the oxidation process at ambient temperature and the quantity of oxygen absorption. Therefore, the simple and cheap mass scaling method is suitable for predicting the oxygen absorption performance of sulfide ores at ambient temperature in place of the expensive and complicated chemical method used hitherto. Furthermore, combined with other items of breeding-fire test, the mass increase potential can also be used to predict the spontaneous combustion tendency of sulfide ores.

  2. Interfacial tension studies between Fe-Cu-Ni sulfide and halo-norilsk basalt slag system

    Institute of Scientific and Technical Information of China (English)

    SU; Shangguo

    2005-01-01

    The interfacial tension of the matte/halo-Norilsk basalt slag systems of FeS-Cu2S-Ni3S2 and FeO-FeS were investigated using the sessile drop technique. The results indicate that interfacial tension decreases with increasing copper and nickel contents in the matte of FeS-Cu2S-Ni3S2 system while it increases with increasing oxygen content in the matte of FeO-FeS system. It is inferred from these results that two conditions are critical for the formation of giant Cu-Ni sulfide deposits. One is that mafic-ultramafic parent magma of sulfide deposits should be rich in copper and nickel where due to the low interfacial tension, it is difficult to form sulfide droplet in the early stage of magma evolution. In other words, sulfide liquid conglomeration occurs more difficultly. The other condition is that the magma emplacement should be shallow; and a lot of faults occur in the magma emplacement field. Since oxygen content is high in the environment, interfacial tension is high, which helps sulfide liquid conglomeration and consequently Cu-Ni sulfide deposits form.

  3. Sulphidization flotation for recovery of lead and zinc from oxide-sulfide ores

    Institute of Scientific and Technical Information of China (English)

    FA Keqing; Jan D.Miller; JIANG Tao; LI Guang-hui

    2005-01-01

    A new flowsheet was developed to recover the valuable minerals from oxide or oxide-sulfide ores of lead and zinc. The flowsheet consisted of flotation of sulfide minerals, desliming and sulphidization-flotation of oxide minerals. The corresponding reagent system and techniques to the flowsheet were investigated. Batch and continuous tests show that the dosage of sodium sulfide, temperature, and collector type are main affecting factors on the recovery of smithsonite and cerussite. For the flotation of cerussite, there is an appropriate dosage of sodium sulfide at which the recovery reaches its maximum value. The required sodium sulfide for smithsonite flotation is higher than that for cerussite and the recovery of smithsonite flotation increases with the dosage of sodium sulfide at low level and becomes insensitive at high dosage. The appropriate temperature for smithsonite and cerussite flotation is found to be 25 - 40 ℃. Amines are found to be the effective collectors for the flotation of smithsonite after sulphidization. Investigation also shows that desliming prior to sulphidization-flotation is essential to the effective recovery of smithsonite and cerussite, and the desliming process of two-stage hydrocyclon is well feasible and effective for the treatment of lead-zinc oxide ores. A further treatment on the cerussite flotation concentrate by shaking table is proposed to obtain higher lead grade.

  4. Sulfide assemblages in granulite xenoliths from Hannuoba Basalt, Hebei Province, China

    Institute of Scientific and Technical Information of China (English)

    Jiuhua Xu; Yuling Xie; Xuelei Chu; Jianming Liu; Qian Mao

    2005-01-01

    Granulite xenoliths are important samples for understanding the forming and evolution of the crust. The granulite xenoliths enclosed in Cenozoic basalt of Hannuoba, Hebei Province, China, contain four types of sulfide assemblages: isolate rotundity enclosed sulfides, intergranular sulfides between minerals, secondary sulfide inclusions ranging in linear, and fissure-filling sulfides.Electron microprobe analysis shows that the components of sulfides are Ni-poor pyrrhotite with the molar ratios of (Ni+Co+Cu)/Fe less than 0.2. The molar ratios of (Fe+Cu+Co+Ni)/S are less than 0.875 of normal pyrrhotite, and are less than those of mantle xenoliths, reflecting a sulfur-saturated environment. Pyrrhotite in various occurrences contains some Au and Ag, with the averages of 0.19wt%-0.22wt% Au and 0.01 wt%-0.02wt% Ag, showing the gold mineralization related to the granulitization of low crust. Ni, Co and Cu have a normal correlation with S in pyrrhotite, indicating that heavy metal elements have a same source similar to sulfur because of the degasification of upper mantle.

  5. Mitochondrial Sulfide Detoxification Requires a Functional Isoform O-Acetylserine(thiol)lyase C in Arabidopsis thaliana

    Institute of Scientific and Technical Information of China (English)

    Consolación (A)lvarez; Irene García; Luis C.Romero; Cecilia Gotor

    2012-01-01

    In non-cyanogenic species,the main source of cyanide derives from ethylene and camalexin biosyntheses.In mitochondria,cyanide is a potent inhibitor of the cytochrome c oxidase and is metabolized bythe β-cyanoalanine synthase CYS-C1,catalyzing the conversion of cysteine and cyanide to hydrogen sulfide and β-cyanoalanine.The hydrogen sulfide released also inhibits the cytochrome c oxidase and needs to be detoxified by the O-acetylserine(thiol)lyase mitochondrial isoform,OAS-C,which catalyzes the incorporation of sulfide to O-acetylserine to produce cysteine,thus generating a cyclic pathway in the mitochondria.The loss of functional OAS-C isoforms causes phenotypic characteristics very similar to the loss of the CYS-C1 enzyme,showing defects in root hair formation.Genetic complementation with the OAS-C gene rescues the impairment of root hair elongation,restoring the wild-type phenotype.The mitochondria compromise their capacity to properly detoxify cyanide and the resulting sulfide because the latter cannot re-assimilate into cysteine in the oas-c null mutant.Consequently,we observe an accumulation of sulfide and cyanide and of the alternative oxidase,which is unable to prevent the production of reactive oxygen species probably due to the accumulation of both toxic molecules.Our results allow us to suggest that the significance of OAS-C is related to its role in the proper sulfide and cyanide detoxification in mitochondria.

  6. Potential for biogeochemical cycling of sulfur, iron and carbon within massive sulfide deposits below the seafloor.

    Science.gov (United States)

    Kato, Shingo; Ikehata, Kei; Shibuya, Takazo; Urabe, Tetsuro; Ohkuma, Moriya; Yamagishi, Akihiko

    2015-05-01

    Seafloor massive sulfides are a potential energy source for the support of chemosynthetic ecosystems in dark, deep-sea environments; however, little is known about microbial communities in these ecosystems, especially below the seafloor. In the present study, we performed culture-independent molecular analyses of sub-seafloor sulfide samples collected in the Southern Mariana Trough by drilling. The depth for the samples ranged from 0.52 m to 2.67 m below the seafloor. A combination of 16S rRNA and functional gene analyses suggested the presence of chemoautotrophs, sulfur-oxidizers, sulfate-reducers, iron-oxidizers and iron-reducers. In addition, mineralogical and thermodynamic analyses are consistent with chemosynthetic microbial communities sustained by sulfide minerals below the seafloor. Although distinct bacterial community compositions were found among the sub-seafloor sulfide samples and hydrothermally inactive sulfide chimneys on the seafloor collected from various areas, we also found common bacterial members at species level including the sulfur-oxidizers and sulfate-reducers, suggesting that the common members are widely distributed within massive sulfide deposits on and below the seafloor and play a key role in the ecosystem function.

  7. Investigation of the Electrocatalytic Activity of Rhodium Sulfide for Hydrogen Evolution and Hydrogen Oxidation

    International Nuclear Information System (INIS)

    We report the synthesis of unsupported and carbon-supported, mixed phase, rhodium sulfide, using both a hydrogen sulfide source and a solid sulfur source. Samples with several different distributions of rhodium sulfide phases (Rh2S3, Rh17S15, RhS2 and metallic Rh) were obtained by varying the temperature and exposure time to H2S or sulfur to rhodium ratio when using solid sulfur. Samples were characterized by X-ray diffraction (XRD), and the unsupported rhodium sulfide compounds studied using Raman spectroscopy to link Raman spectra to catalyst phases. The electrocatalytic activity of the rhodium sulfide compounds for hydrogen evolution and oxidation was measured using rotating disk electrode measurements in acidic conditions to simulate use in a flow cell. The most active phases for hydrogen evolution were found to be Rh3S4 and Rh17S15 (−0.34 V vs. Ag/AgCl required for 20 mA/cm2), while Rh2S3 and RhS2 phases were relatively inactive (−0.46 V vs. Ag/AgCl required for 20 mA/cm2 using RhS2/C). The hydrogen oxidation activity of all rhodium sulfide phases is significantly lower than the hydrogen evolution activity and is not associated with conductivity limitations

  8. Sedimentary-hosted polymetallic massive sulfide deposits of the Kebrit and Shaban Deeps, Red Sea

    Science.gov (United States)

    Blum, N.; Puchelt, H.

    1991-07-01

    Massive sulfides recovered from the Kebrit Deep carbonaceous sedimentary succession represent black smoker fragments, novel to any Red Sea brine pool deposit. Chimneys, which were also observed in situ near the seawater/brine interface of the Kebrit Deep pool, are primarily comprised of Fe-, Zn- and Pb-bearing phases, and are often tar and asphalt impregnated. Cu-sulfides are virtually absent from parageneses, contrasting rift-related smoker and Red Sea metalliferous sediment deposits. Concentration of nickel in discrete bravoite points to a basalt/seawater leaching process as a source for most metals. The sedimentary package, which probably hosts Cu-mineralization in lower stockworks of the smoker deposit, is considered the major source of lead. Prevention of boiling of hydrothermal fluids, passing through a succession of organic-rich carbonate and clay horizons prior to discharge, is essential for smoker formation. Shaban Deep sedimentary-hosted massive sulfides are less frequent, with pyrite being the dominant ore mineral. Sulfur isotope data indicate both high temperature inorganic as well as biogenic sulfate (seawater and/or evaporite) reduction in sulfide-forming processes. Cogenetic sulfates formed from residual, bacteriogenically reduced seawater sulfate. Rather low sulfide/sulfate precipitation temperatures of 110 130 °C for the Kebrit brine pool and 100 °C for Shaban Deep massive sulfides are evident.

  9. Characterization of lacustrine iron sulfide particles with proton-induced X-ray emission

    International Nuclear Information System (INIS)

    Black particles, collected by filtration (1.2-μ pore size) from the anoxic waters of a soft-water lake, were examined by a scanning proton microprobe which permitted quantitative elemental analysis by proton-induced X-ray emission (PIXE) and Rutherford backscattering (RBS). There was a uniform distribution of sulfur across the filter, but Fe, and to a lesser extent, Mn, was localized in ∼5-μm diameter clusters. Elemental analysis with 1-μm-diameter beams revealed that the Fe clusters were mainly comprised of iron oxides. Iron sulfide material not in the Fe clusters had stoichiometric proportions of Fe1.0S0.60P0.60Ca0.24K0.14. Although a purely biogenic origin for P, Ca, and K cannot be ruled out, the composition is consistent with the particles originating as authigenic iron oxides which react with sulfide as they sink through the water column. The iron sulfide particles are richer in Cu (4,000 ppm) and Zn (6,000 ppm) than the iron oxides, suggesting that these elements are also concentrated as their insoluble sulfides. The coexistence of iron oxides and sulfides indicates that either the supply of sulfide is limiting or that some iron oxide particles are unreactive. 20 refs., 2 figs., 1 tab

  10. Positive trends in Southern Hemisphere observations of carbonyl sulfide

    Science.gov (United States)

    Kremser, Stefanie; Jones, Nicholas; Smale, Dan; Palm, Mathias; Lejeune, Bernard; Wang, Yuting; Deutscher, Nicholas

    2016-04-01

    Carbonyl sulfide (OCS; lifetime of about 5.7 years) is the longest lived reduced sulfur-containing gas in the atmosphere. The primary source of OCS is the ocean, which is both a direct source (through OCS emission) and an indirect source (due to oxidation of carbon disulfide, CS2, and dimethyl sulfide). Other natural sources of OCS include volcanic outgassing and direct fluxes from wetland regions. The removal of OCS from the atmosphere is dominated by soil and vegetation uptake, with minor contributions from reactions with the hydroxyl radical. Small anthropogenic sources of OCS are coal combustion, biomass burning, and aluminum production. A dominant indirect source results from CS2 emissions from the rayon industry. Transport of tropospheric OCS to the stratosphere during volcanically quiescent periods has been suggested to contribute sulfur to the stratospheric aerosol layer which affects atmospheric radiative balance. If, however, production of stratospheric aerosols from OCS oxidation is smaller than typical estimates, this OCS contribution would be overestimated. The magnitude of the OCS flux to the stratosphere is currently not well quantified as is the relative contribution of OCS to background aerosol loading. While earlier model simulations indicate OCS fluxes into the atmosphere exceeding removal, past total column observations of OCS show no significant trend. Analysis of tropospheric OCS columns at Arrival Heights (Antarctica) and Lauder (New Zealand) show strong positive trends from 2001-2008 followed by weaker trends to 2015, with unexpected temporal coherence. Since trends in ocean and land sources/sinks at these two sites, respectively, are unlikely to be similar, the coherence in trend structure likely results from changes in transport of OCS from the tropics to middle and high latitudes. Potential causes for OCS increases are (i) increases in tropical lower stratospheric OCS and/or (ii) strengthening of the large-scale circulation which

  11. Thioethers as markers of hydrogen sulfide production in homocystinurias.

    Science.gov (United States)

    Kožich, Viktor; Krijt, Jakub; Sokolová, Jitka; Melenovská, Petra; Ješina, Pavel; Vozdek, Roman; Majtán, Tomáš; Kraus, Jan P

    2016-07-01

    Two enzymes in the transsulfuration pathway of homocysteine -cystathionine beta-synthase (CBS) and gamma-cystathionase (CTH)-use cysteine and/or homocysteine to produce the important signaling molecule hydrogen sulfide (H2S) and simultaneously the thioethers lanthionine, cystathionine or homolanthionine. In this study we explored whether impaired flux of substrates for H2S synthesis and/or deficient enzyme activities alter production of hydrogen sulfide in patients with homocystinurias. As an indirect measure of H2S synthesis we determined by LC-MS/MS concentrations of thioethers in plasma samples from 33 patients with different types of homocystinurias, in 8 patient derived fibroblast cell lines, and as reaction products of seven purified mutant CBS enzymes. Since chaperoned recombinant mutant CBS enzymes retained capacity of H2S synthesis in vitro it can be stipulated that deficient CBS activity in vivo may impair H2S production. Indeed, in patients with classical homocystinuria we observed significantly decreased cystathionine and lanthionine concentrations in plasma (46% and 74% of median control levels, respectively) and significantly lower cystathionine in fibroblasts (8% of median control concentrations) indicating that H2S production from cysteine and homocysteine may be also impaired. In contrast, the grossly elevated plasma levels of homolanthionine in CBS deficient patients (32-times elevation compared to median of controls) clearly demonstrates a simultaneous overproduction of H2S from homocysteine by CTH. In the remethylation defects the accumulation of homocysteine and the increased flux of metabolites through the transsulfuration pathway resulted in elevation of cystathionine and homolanthionine (857% and 400% of median control values, respectively) indicating a possibility of an increased biosynthesis of H2S by both CBS and CTH. This study shows clearly disturbed thioether concentrations in homocystinurias, and modeling using these data indicates

  12. Reduced ternary molybdenum and tungsten sulfides and hydroprocessing catalysis therewith

    Science.gov (United States)

    Hilsenbeck, Shane J.; McCarley, Robert E.; Schrader, Glenn L.; Xie, Xiaobing

    1999-02-16

    New amorphous molybdenum/tungsten sulfides with the general formula M.sup.n+.sub.2x/n (L.sub.6 S.sub.8)S.sub.x, where L is molybdenum or tungsten and M is a ternary metal, has been developed. Characterization of these amorphous materials by chemical and spectroscopic methods (IR, Raman, PES) shows that the (M.sub.6 S.sub.8).sup.0 cluster units are present. Vacuum thermolysis of the amorphous Na.sub.2x (Mo.sub.6 S.sub.8)S.sub.x .multidot.yMeOH first produces poorly crystalline NaMo.sub.6 S.sub.8 by disproportionation at 800.degree. C. and well-crystallized NaMo.sub.6 S.sub.8 at .gtoreq. 900.degree. C. Ion-exchange of the sodium material in methanol with soluble M.sup.2+ and M.sup.3+ salts (M=Sn, Co, Ni, Pb, La, Ho) produces the M.sup.n+.sub.2x/n (Mo.sub.6 S.sub.8)S.sub.x .multidot.yMeOH compounds. Additionally, the new reduced ternary molybdenum sulfides with the general formula M.sup.n+.sub.2x/n Mo.sub.6 S.sub.8+x (MeOH).sub.y ›MMOS! (M=Sn, Co, Ni) is an effective hydrodesulfurization (HDS) catalyst both as-prepared and after a variety of pretreatment conditions. Under specified pretreatment conditions with flowing hydrogen gas, the SnMoS type catalyst can be stabilized, and while still amorphous, can be considered as "Chevrel phase-like" in that both contain Mo.sub.6 S.sub.8 cluster units. Furthermore, the small cation NiMoS and CoMoS type pretreated catalyst showed to be very active HDS catalysts with rates that exceeded the model unpromoted and cobalt-promoted MoS.sub.2 catalysts.

  13. Effect of Sulfur Content and Sulfide Shape on Fracture Ductility in Case Hardening Steel%Effect of Sulfur Content and Sulfide Shape on Fracture Ductility in Case Hardening Steel

    Institute of Scientific and Technical Information of China (English)

    XIAO Guo-hua; DONG Han; WANG Mao-qiu; HUI Wei-jun

    2011-01-01

    The effects of sulfur content and calcium addition on smooth axisymmetric tensile fracture ductility of case hardening steel DIN 18CrNiMo7-6 have been investigated. The quantitative metallographic analysis of sulfide inclusions and the correlations between sulfide inclusions and fracture ductility were examined. Sulfide inclusions were found to have deleterious effect on fracture ductility, whereas the effect can be offset to some extent by calcium-treat- ment due to less easily deforming of sulfides during hot-working. The product (AA·λAW) of sulfide inclusion area fraction (An) and its area-weighted aspect ratio (λAW) can be used as a parameter to describe the effect of sulfide inclusions on fracture true strain.

  14. The Voisey's Bay Ni-Cu-Co Sulfide Deposit,Labrador,Canada:Emplacement of Silicate and Sulfide-Laden Magmas into Spaces Created within a Structural Corridor%The Voisey's Bay Ni-Cu-Co Sulfide Deposit,Labrador, Canada: Emplacement of Silicate and Sulfide-Laden Magmas into Spaces Created within a Structural Corridor

    Institute of Scientific and Technical Information of China (English)

    Peter C.Lightfoot; Dawn Evans-Lamswood; Robert Wheeler

    2012-01-01

    Abstract:The Voisey's Bay Ni-Cu-Co sulfide deposit is hosted in a 1.34 Ga mafic intrusion that is part of the Nain Plutonic Suite in Labrador,Canada.The Ni-Cu-Co sulfide mineralization is associated with magmatic breccias that are typically contained in weakly mineralized olivine gabbros,troctolites and ferrogabbros,but also occur as veins in adjacent paragneiss.The mineralization is associated with a dyke-like body which is termed the feeder dyke.This dyke connects the shallow differentiated Eastern Deeps chamber in the east to a deeper intrusion in the west termed the Western Deeps Intrusion.Where the conduit is connected to the Eastern Deeps Intrusion,the Eastern Deeps Deposit is developed at the entry line of the dyke along the steep north wall of the Eastern Deeps Intrusion.The Eastern Deeps Deposit is surrounded by a halo of moderately to weakly mineralized Variable-Textured Troctolite (VTT) that reaches a maximum thickness above the ENE-WSW axis of the Eastern Deeps Deposit.At depth to the west,the conduit is adjacent to the south side of the Western Deeps Intrusion,where the dyke and intrusion contain disseminated magmatic sulfide mineralization.The Reid Brook Zone plunges to the east within the dyke,and both the dyke and adjacent paragneiss are mineralized.The Ovoid Deposit comprises a bowl-shaped body of massive sulfide where the dyke widens near to the present-day surface.It is not clear whether this deposit was developed as a widened-zone within the conduit or at the entry point into a chamber that is now lost to erosion.The massive sulfides and breccia sulfides of the Eastern Deeps are petrologically and chemically different when compared to the disseminated sulfides in the VTT; there is a marked break in Ni tenor (Ni content in 100% sulfide,abbreviated to [Ni] 100) and Ni/Co of sulfide between the two.The boundary of the sulfide types is often marked by strong sub-horizontal alignment of heavily digested and metamorphosed paragneiss fragments

  15. Dimethyl sulfide as a source of cloud condensation nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Warren, S. [Univ. of Washington, Seattle, WA (United States)

    1995-09-01

    Cloud condensation nuclei (CCN) are predominantly sulfate particles, and over the oceans the major source of sulfur for these particles appears to be dimethyl sulfide, a gas produced by marine biota. The reflection of sunlight by marine stratiform clouds is a major feature of the Earth`s radiation budget, and these clouds will reflect more sunlight if their liquid water is distributed among more CCN, thus forming more (and smaller) droplets. These facts form the basis of a proposal that marine biogenic sulfur may be an important factor in determining the Earth`s climate. Key implications of this proposal are (1) the possibility of a biota-climate feedback loop if the production of biogenic sulfur is sensitive to changes in climate, (2) the possibility that anthropogenic sulfur emissions may be altering the global climate through this cloud-mediated mechanism, and (3) the possibility that anthropogenic pollution could alter climate by perturbing the sulfur-producing marine organisms. 3 refs., 1 fig.

  16. Role of Hydrogen Sulfide in the Pathology of Inflammation

    Directory of Open Access Journals (Sweden)

    Madhav Bhatia

    2012-01-01

    Full Text Available Hydrogen sulfide (H2S is a well-known toxic gas that is synthesized in the human body from the amino acids cystathionine, homocysteine, and cysteine by the action of at least two distinct enzymes: cystathionine-γ-lyase and cystathionine-β-synthase. In the past few years, H2S has emerged as a novel and increasingly important biological mediator. Imbalances in H2S have also been shown to be associated with various disease conditions. However, defining the precise pathophysiology of H2S is proving to be a complex challenge. Recent research in our laboratory has shown H2S as a novel mediator of inflammation and work in several groups worldwide is currently focused on determining the role of H2S in inflammation. H2S has been implicated in different inflammatory conditions, such as acute pancreatitis, sepsis, joint inflammation, and chronic obstructive pulmonary disease (COPD. Active research on the role of H2S in inflammation will unravel the pathophysiology of its actions in inflammatory conditions and may help develop novel therapeutic approaches for several, as yet incurable, disease conditions.

  17. Epithelial Electrolyte Transport Physiology and the Gasotransmitter Hydrogen Sulfide

    Directory of Open Access Journals (Sweden)

    Ervice Pouokam

    2016-01-01

    Full Text Available Hydrogen sulfide (H2S is a well-known environmental chemical threat with an unpleasant smell of rotten eggs. Aside from the established toxic effects of high-dose H2S, research over the past decade revealed that cells endogenously produce small amounts of H2S with physiological functions. H2S has therefore been classified as a “gasotransmitter.” A major challenge for cells and tissues is the maintenance of low physiological concentrations of H2S in order to prevent potential toxicity. Epithelia of the respiratory and gastrointestinal tract are especially faced with this problem, since these barriers are predominantly exposed to exogenous H2S from environmental sources or sulfur-metabolising microbiota. In this paper, we review the cellular mechanisms by which epithelial cells maintain physiological, endogenous H2S concentrations. Furthermore, we suggest a concept by which epithelia use their electrolyte and liquid transport machinery as defence mechanisms in order to eliminate exogenous sources for potentially harmful H2S concentrations.

  18. The oceanic cycle and global atmospheric budget of carbonyl sulfide

    Energy Technology Data Exchange (ETDEWEB)

    Weiss, P.S.

    1994-12-31

    A significant portion of stratospheric air chemistry is influenced by the existence of carbonyl sulfide (COS). This ubiquitous sulfur gas represents a major source of sulfur to the stratosphere where it is converted to sulfuric acid aerosol particles. Stratospheric aerosols are climatically important because they scatter incoming solar radiation back to space and are able to increase the catalytic destruction of ozone through gas phase reactions on particle surfaces. COS is primarily formed at the surface of the earth, in both marine and terrestrial environments, and is strongly linked to natural biological processes. However, many gaps in the understanding of the global COS cycle still exist, which has led to a global atmospheric budget that is out of balance by a factor of two or more, and a lack of understanding of how human activity has affected the cycling of this gas. The goal of this study was to focus on COS in the marine environment by investigating production/destruction mechanisms and recalculating the ocean-atmosphere flux.

  19. High-temperature study of superconducting hydrogen and deuterium sulfide

    Energy Technology Data Exchange (ETDEWEB)

    Durajski, A.P. [Institute of Physics, Czestochowa University of Technology, Ave. Armii Krajowej 19, 42-200 Czestochowa (Poland); Szczesniak, R. [Institute of Physics, Czestochowa University of Technology, Ave. Armii Krajowej 19, 42-200 Czestochowa (Poland); Institute of Physics, Jan Dlugosz University, Ave. Armii Krajowej 13/15, 42-200 Czestochowa (Poland); Pietronero, L. [Sapienza, Universita di Roma, Dip. Fisica, P. le A. Moro 2, 00185 Roma (Italy); Institute of Complex Systems, CNR, Via dei Taurini 19 Roma (Italy); London Institute for Mathematical Sciences, South Street 22, Mayfair London (United Kingdom)

    2016-05-15

    Hydrogen-rich compounds are extensively explored as candidates for a high-temperature superconductors. Currently, the measured critical temperature of 203 K in hydrogen sulfide (H{sub 3}S) is among the highest over all-known superconductors. In present paper, using the strong-coupling Eliashberg theory of superconductivity, we compared in detail the thermodynamic properties of two samples containing different hydrogen isotopes H{sub 3}S and D{sub 3}S at 150 GPa. Our research indicates that it is possible to reproduce the measured values of critical temperature 203 K and 147 K for H{sub 3}S and D{sub 3}S by using a Coulomb pseudopotential of 0.123 and 0.131, respectively. However, we also discuss a scenario in which the isotope effect is independent of pressure and the Coulomb pseudopotential for D{sub 3}S is smaller than for H{sub 3}S. For both scenarios, the energy gap, specific heat, thermodynamic critical field and related dimensionless ratios are calculated and compared with other conventional superconductors. We shown that the existence of the strong-coupling and retardation effects in the systems analysed result in significant differences between values obtained within the framework of the Eliashberg formalism and the prediction of the Bardeen-Cooper-Schrieffer theory. (copyright 2015 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. Preparation of zinc sulfide nanocrystallites from single-molecule precursors

    Science.gov (United States)

    Palve, Anil M.; Garje, Shivram S.

    2011-07-01

    Zinc sulfide nanocrystallites were prepared using Zinc(II) thiosemicarbazone complexes of the types Zn(L) 2 and ZnCl 2(LH) 2 (where, LH=thiosemicarbazones of cinnamaldehyde, 4-chlorobenzaldehyde, indol-3-carboxaldehyde and thiophene-2-carboxaldehyde) as single source precursors by solvothermal decomposition in ethylene glycol and ethylene diamine in few cases. The materials were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction, energy dispersive X-ray analysis and UV-vis and IR spectroscopy. Solvothermal decomposition in ethylene glycol resulted in the formation of hexagonal ZnS (JCPDS: 36-1450) as evident from the XRD patterns. However, XRD shows formation of hybrid material, ZnS 0.5EN in case of solvothermal decomposition in ethylenediamine. Infrared spectra authenticate the capping of ethylene glycol and ethylenediamine on ZnS and ZnS 0.5EN, respectively. TEM images showed formation of spherical nanoparticles for the materials obtained from ethylene glycol, whereas plate-like morphology is observed in case of materials obtained from ethylene diamine. The blue shift of absorption bands compared to bands of bulk materials in the UV-vis spectra supports the formation of smaller particles.

  1. Hydrogen Sulfide in Physiology and Diseases of the Digestive Tract

    Directory of Open Access Journals (Sweden)

    Sudha B. Singh

    2015-11-01

    Full Text Available Hydrogen sulfide (H2S is a Janus-faced molecule. On one hand, several toxic functions have been attributed to H2S and exposure to high levels of this gas is extremely hazardous to health. On the other hand, H2S delivery based clinical therapies are being developed to combat inflammation, visceral pain, oxidative stress related tissue injury, thrombosis and cancer. Since its discovery, H2S has been found to have pleiotropic effects on physiology and health. H2S is a gasotransmitter that exerts its effect on different systems, such as gastrointestinal, neuronal, cardiovascular, respiratory, renal, and hepatic systems. In the gastrointestinal tract, in addition to H2S production by mammalian cystathionine-β-synthase (CBS, cystathionine-γ-lyase (CSE, H2S is also generated by the metabolic activity of resident gut microbes, mainly by colonic Sulfate-Reducing Bacteria (SRB via a dissimilatory sulfate reduction (DSR pathway. In the gut, H2S regulates functions such as inflammation, ischemia/ reperfusion injury and motility. H2S derived from gut microbes has been found to be associated with gastrointestinal disorders such as ulcerative colitis, Crohn’s disease and irritable bowel syndrome. This underscores the importance of gut microbes and their production of H2S on host physiology and pathophysiology.

  2. The Significance of Hydrogen Sulfide for Arabidopsis Seed Germination.

    Science.gov (United States)

    Baudouin, Emmanuel; Poilevey, Aurélie; Hewage, Nishodi Indiketi; Cochet, Françoise; Puyaubert, Juliette; Bailly, Christophe

    2016-01-01

    Hydrogen sulfide (H2S) recently emerged as an important gaseous signaling molecule in plants. In this study, we investigated the possible functions of H2S in regulating Arabidopsis seed germination. NaHS treatments delayed seed germination in a dose-dependent manner and were ineffective in releasing seed dormancy. Interestingly, endogenous H2S content was enhanced in germinating seeds. This increase was correlated with higher activity of three enzymes (L-cysteine desulfhydrase, D-cysteine desulfhydrase, and β-cyanoalanine synthase) known as sources of H2S in plants. The H2S scavenger hypotaurine and the D/L cysteine desulfhydrase inhibitor propargylglycine significantly delayed seed germination. We analyzed the germinative capacity of des1 seeds mutated in Arabidopsis cytosolic L-cysteine desulfhydrase. Although the mutant seeds do not exhibit germination-evoked H2S formation, they retained similar germination capacity as the wild-type seeds. In addition, des1 seeds responded similarly to temperature and were as sensitive to ABA as wild type seeds. Taken together, these data suggest that, although its metabolism is stimulated upon seed imbibition, H2S plays, if any, a marginal role in regulating Arabidopsis seed germination under standard conditions. PMID:27446159

  3. Physiological Importance of Hydrogen Sulfide: Emerging Potent Neuroprotector and Neuromodulator.

    Science.gov (United States)

    Panthi, Sandesh; Chung, Hyung-Joo; Jung, Junyang; Jeong, Na Young

    2016-01-01

    Hydrogen sulfide (H2S) is an emerging neuromodulator that is considered to be a gasotransmitter similar to nitrogen oxide (NO) and carbon monoxide (CO). H2S exerts universal cytoprotective effects and acts as a defense mechanism in organisms ranging from bacteria to mammals. It is produced by the enzymes cystathionine β-synthase (CBS), cystathionine ϒ-lyase (CSE), 3-mercaptopyruvate sulfurtransferase (MST), and D-amino acid oxidase (DAO), which are also involved in tissue-specific biochemical pathways for H2S production in the human body. H2S exerts a wide range of pathological and physiological functions in the human body, from endocrine system and cellular longevity to hepatic protection and kidney function. Previous studies have shown that H2S plays important roles in peripheral nerve regeneration and degeneration and has significant value during Schwann cell dedifferentiation and proliferation but it is also associated with axonal degradation and the remyelination of Schwann cells. To date, physiological and toxic levels of H2S in the human body remain unclear and most of the mechanisms of action underlying the effects of H2S have yet to be fully elucidated. The primary purpose of this review was to provide an overview of the role of H2S in the human body and to describe its beneficial effects. PMID:27413423

  4. Hydrogen sulfide induced disruption of Na+ homeostasis in the cortex.

    Science.gov (United States)

    Chao, Dongman; He, Xiaozhou; Yang, Yilin; Balboni, Gianfranco; Salvadori, Severo; Kim, Dong H; Xia, Ying

    2012-07-01

    Maintenance of ionic balance is essential for neuronal functioning. Hydrogen sulfide (H(2)S), a known toxic environmental gaseous pollutant, has been recently recognized as a gasotransmitter involved in numerous biological processes and is believed to play an important role in the neural activities under both physiological and pathological conditions. However, it is unclear if it plays any role in maintenance of ionic homeostasis in the brain under physiological/pathophysiological conditions. Here, we report by directly measuring Na(+) activity using Na(+) selective electrodes in mouse cortical slices that H(2)S donor sodium hydrosulfide (NaHS) increased Na(+) influx in a concentration-dependent manner. This effect could be partially blocked by either Na(+) channel blocker or N-methyl-D-aspartate receptor (NMDAR) blocker alone or almost completely abolished by coapplication of both blockers but not by non-NMDAR blocker. These data suggest that increased H(2)S in pathophysiological conditions, e.g., hypoxia/ischemia, potentially causes a disruption of ionic homeostasis by massive Na(+) influx through Na(+) channels and NMDARs, thus injuring neural functions. Activation of delta-opioid receptors (DOR), which reduces Na(+) currents/influx in normoxia, had no effect on H(2)S-induced Na(+) influx, suggesting that H(2)S-induced disruption of Na(+) homeostasis is resistant to DOR regulation and may play a major role in neuronal injury in pathophysiological conditions, e.g., hypoxia/ischemia.

  5. Depolarizing actions of hydrogen sulfide on hypothalamic paraventricular nucleus neurons.

    Directory of Open Access Journals (Sweden)

    C Sahara Khademullah

    Full Text Available Hydrogen sulfide (H2S is a novel neurotransmitter that has been shown to influence cardiovascular functions as well and corticotrophin hormone (CRH secretion. Since the paraventricular nucleus of the hypothalamus (PVN is a central relay center for autonomic and endocrine functions, we sought to investigate the effects of H2S on the neuronal population of the PVN. Whole cell current clamp recordings were acquired from the PVN neurons and sodium hydrosulfide hydrate (NaHS was bath applied at various concentrations (0.1, 1, 10, and 50 mM. NaHS (1, 10, and 50 mM elicited a concentration-response relationship from the majority of recorded neurons, with almost exclusively depolarizing effects following administration. Cells responded and recovered from NaHS administration quickly and the effects were repeatable. Input differences from baseline and during the NaHS-induced depolarization uncovered a biphasic response, implicating both a potassium and non-selective cation conductance. The results from the neuronal population of the PVN shed light on the possible physiological role that H2S has in autonomic and endocrine function.

  6. Biochemistry and therapeutic potential of hydrogen sulfide - reality or fantasy?

    Science.gov (United States)

    Brodek, Paulina; Olas, Beata

    2016-01-01

    Hydrogen sulfide (H2S) is a signaling gasotransmitter, involved in different physiological and pathological processes. H2S regulates apoptosis, the cell cycle and oxidative stress. H2S exerts powerful effects on smooth muscle cells, endothelial cells, inflammatory cells, endoplasmic reticulum, mitochondria and nuclear transcription factors. H2S is known to be produced from L-cysteine, D-cysteine and L-homocysteine in the body. Four enzymes - cystathionine-b synthase (CBS), mercaptopyruvate sulfurtransferase (3-MST), cystathionine-γ lyase (CSE) and cysteine aminotransferase (CAT) - are involved in H2S synthesis. The biosynthetic pathway for the production of H2S from D-cysteine involves 3-MST and D-amino acid oxidase (DAO). The therapeutic potential of H2S is not clear. However, recently results have demonstrated that H2S has protective action for ischemic heart disease or hypertension, and protects against ischemia of the brain. This review summarizes the negative and the positive roles of H2S in various biological systems, for example the cardiovascular system and nervous system. We also discuss the function of classical, therapeutic and natural (for example garlic) donors of H2S in pre-clinical and clinical studies. PMID:27516569

  7. Potentiation of lymphocyte proliferative responses by nickel sulfide

    Science.gov (United States)

    Jaramillo, A.; Sonnenfeld, G.

    1992-01-01

    Crystalline nickel sulfide (NiS) induced a spleen cell proliferation that resembles a mixed lymphocyte reaction (MLR). It depended on cell-cell interaction, induced high levels of interleukin-1 (IL-1) and interleukin-2 (IL-2) and the responding cell subpopulation was composed of CD4+ T lymphocytes. Furthermore, the proliferation was inhibited in a dose-dependent manner by magnesium. Crystalline NiS also increased significantly the spleen cell proliferative response to concanavalin A (Con A) and lipopolysaccharide (LPS) with magnesium potentiating the combined effects of crystalline NiS and mitogens. Interestingly, crystalline NiS did not show any effect on the induction of IL-2 by Con A. The results described herein suggest that crystalline NiS can potentiate both antigenic (MLR) and mitogenic (Con A and LPS) proliferative responses in vitro. Crystalline NiS appears to potentiate these responses by acting in the form of ionic nickel on several intracellular targets for which magnesium ions have different noncompetitive interactions. The effects of magnesium on the potentiating action of crystalline NiS are different depending upon the type of primary stimulatory signal for proliferation (mitogenic or antigenic).

  8. The Significance of Hydrogen Sulfide for Arabidopsis Seed Germination

    Science.gov (United States)

    Baudouin, Emmanuel; Poilevey, Aurélie; Hewage, Nishodi Indiketi; Cochet, Françoise; Puyaubert, Juliette; Bailly, Christophe

    2016-01-01

    Hydrogen sulfide (H2S) recently emerged as an important gaseous signaling molecule in plants. In this study, we investigated the possible functions of H2S in regulating Arabidopsis seed germination. NaHS treatments delayed seed germination in a dose-dependent manner and were ineffective in releasing seed dormancy. Interestingly, endogenous H2S content was enhanced in germinating seeds. This increase was correlated with higher activity of three enzymes (L-cysteine desulfhydrase, D-cysteine desulfhydrase, and β-cyanoalanine synthase) known as sources of H2S in plants. The H2S scavenger hypotaurine and the D/L cysteine desulfhydrase inhibitor propargylglycine significantly delayed seed germination. We analyzed the germinative capacity of des1 seeds mutated in Arabidopsis cytosolic L-cysteine desulfhydrase. Although the mutant seeds do not exhibit germination-evoked H2S formation, they retained similar germination capacity as the wild-type seeds. In addition, des1 seeds responded similarly to temperature and were as sensitive to ABA as wild type seeds. Taken together, these data suggest that, although its metabolism is stimulated upon seed imbibition, H2S plays, if any, a marginal role in regulating Arabidopsis seed germination under standard conditions.

  9. The metallization and superconductivity of dense hydrogen sulfide

    International Nuclear Information System (INIS)

    Hydrogen sulfide (H2S) is a prototype molecular system and a sister molecule of water (H2O). The phase diagram of solid H2S at high pressures remains largely unexplored arising from the challenges in dealing with the pressure-induced weakening of S–H bond and larger atomic core difference between H and S. Metallization is yet achieved for H2O, but it was observed for H2S above 96 GPa. However, the metallic structure of H2S remains elusive, greatly impeding the understanding of its metallicity and the potential superconductivity. We have performed an extensive structural study on solid H2S at pressure ranges of 10–200 GPa through an unbiased structure prediction method based on particle swarm optimization algorithm. Besides the findings of candidate structures for nonmetallic phases IV and V, we are able to establish stable metallic structures violating an earlier proposal of elemental decomposition into sulfur and hydrogen [R. Rousseau, M. Boero, M. Bernasconi, M. Parrinello, and K. Terakura, Phys. Rev. Lett. 85, 1254 (2000)]. Our study unravels a superconductive potential of metallic H2S with an estimated maximal transition temperature of ∼80 K at 160 GPa, higher than those predicted for most archetypal hydrogen-containing compounds (e.g., SiH4, GeH4, etc.)

  10. Synthesis and characterisation: Zinc oxide-sulfide nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Verma, Prinsa, E-mail: prinsa.verma@gmail.co [Nanophosphor Application Center, Allahabad University (India); Satish Dhawan Space Center, ISRO (India); Pandey, Avinash C. [Nanophosphor Application Center, Allahabad University (India); Bhargava, R.N. [Nanocrystal Technology, New York (United States)

    2009-11-15

    A novel synthesis method is presented for the preparation of nanosized-semiconductor zinc oxide-sulphide (ZnO/ZnS) core-shell nanocomposites, both formed sequentially from a single-source solid precursor. ZnO nanocrystals were synthesized by a simple co-precipitation method and ZnO/ZnS core-shell nanocomposites were successfully fabricated by sulfidation of ZnO nanocrystals via a facile chemical synthesis at room temperature. The as-obtained samples were characterized by X-ray diffraction and transmission electron microscopy. The results showed that the pure ZnO nanocrystals were hexagonal wurtzite crystal structures and the ZnS nanoparticles were sphalerite structure with the size of about 10 nm grown on the surface of the ZnO nanocrystals. Optical properties measured reveal that ZnO/ZnS core-shell nanocomposites have integrated the photoluminescent effect of ZnO and ZnS. Based on the results of the experiments, a possible formation mechanism of ZnO/ZnS core-shell nanocomposites was also suggested. This treatment is suggested to improve various properties of optoelectronically valuable ZnO/ZnS nanocomposites. These nanosized semiconductor nanocomposites can form a new class of luminescent materials for various applications.

  11. Surface Treatment for Improving Sulfidation Resistance of Fossil Power Systems

    Energy Technology Data Exchange (ETDEWEB)

    Sikka, V.K.

    2001-03-09

    The purpose of the cooperative research and development agreement (CRADA) between ABB Combustion Engineering, Inc. and the Oak Ridge National Laboratory (ORNL) was to develop improved, longer life, and corrosion resistance surfaces for fossil power system components for use primarily in sulfidizing environments. Four surface protection techniques were to be explored. These included diffusion process, weld overlay, hot-isostatic processing, and various spraying methods. The work was to focus on Fe{sub 3} Al-based iron aluminide to increase the component life. The successful completion of the CRADA would have required the achievement of the following four goals: (1) fabrication development, (2) characterization and possibly modification of the alloy to optimize its manufacturability and environmental resistance, (3) testing and evaluation of the specimens, and (4) fabrication and testing of prototype parts. Because of lack of active participation from the participant, this CRADA did not achieve all of its goals and was terminated prematurely. Work carried out at ORNL on the CRADA is described in this report.

  12. Photoluminescence of indium-rich copper indium sulfide quantum dots

    International Nuclear Information System (INIS)

    The enhanced photoluminescence (PL) for In-rich copper indium sulfide quantum dots (CIS QDs) was observed. The conduction electron-Cu vacancy recombination and the donor–acceptor pair (DAP) defect recombination were considered to exist in CIS QDs at the same time. The temperature-dependent PL study showed that the emission of these QDs might be mainly originated from the recombination between electrons in the quantized conduction band and holes in the copper vacancy acceptor when x was 0.500 (CuxIn1−xS). However, the temperature coefficient of PL peak position decreased when x was 0.237. That meant the DAP recombination increased in the In-rich CIS QDs. - Highlights: • The enhanced photoluminescence (PL) for In-rich CuInS2 QDs with [Cu]/[In] molar ratios of 0.31. • The conduction electron-Cu vacancy recombination and DAP were considered to exist and the temperature-independent DAP recombination was enhanced in the In-rich CuInS2 QDs

  13. Characterization of aura tropospheric emissions spectrometer carbonyl sulfide retrievals

    Directory of Open Access Journals (Sweden)

    L. Kuai

    2013-07-01

    Full Text Available We present a description of the Tropospheric Emission Spectrometer (TES carbonyl sulfide (OCS retrieval algorithm, along with evaluation of the biases and uncertainties against aircraft profiles from the HIPPO campaign and data from the NOAA Mauna Loa site. In general, the OCS retrievals (1 have less than 1.0 degree of freedom for signals (DOFs, (2 are sensitive in the mid-troposphere with a peak sensitivity typically between 300 to 500 hPa, (3 but have much smaller systematic errors from temperature, CO2 and H2O calibrations relative to random errors from measurement noise. Here we estimate the monthly means from TES measurements averaged over multiple years so that random errors are reduced and useful information about OCS seasonal and latitudinal variability can be derived. With this averaging, TES OCS data are found to be consistent (within the calculated uncertainties with NOAA ground observations and HIPPO aircraft measurements. TES OCS data also captures the seasonal and latitudinal variations observed by these in situ data.

  14. Hydrogen sulfide facilitates carotid sinus baroreflex in anesthetized rats

    Institute of Scientific and Technical Information of China (English)

    Lin XIAO; Yu-ming WU; Hao ZHANG; Yi-xian LIU; Rui-rong HE

    2006-01-01

    Aim:To study effects of hydrogen sulfide (H2S)on the carotid sinus baroreflex (CSB).Methods:The functional curve of the carotid sinus baroreflex was measured by recording changes in arterial pressure in anesthetized male rats with perfused carotid sinus.Results:H2S(derived from sodium hydrosulfide)at concentrations of 25,50,and 100 μmol/L facilitated the CSB,shifting the functional curve of the baroreflex downward and to the left.There was a marked increase in peak slope(PS)and reflex decrease in blood pressure(RD).Effects were concentration-dependent.Pretreatment with glibenclamide(20 μmol/L),a KATP channel blocker,abolished the above effects of H2S on CSB.Pretreatment with Bay K8644 (an agonist of calcium channels;500 nmol/L)eliminated the effect of H2S on CSB.An inhibitor of cystathionine γ-lyase(CSE),DL-propargylglycine(PPG;200 μmol/L),inhibited CSB in male rats and shifted the functional curve of the baroreflex upward and to the right.Conclusion:These data suggest that exogenous H2S exerts a facilitatory role on isolated CSB through opening KATP channels and further closing the calcium channels in vascular smooth muscle.Endogenous H2S may activate the activity of the CSB in vivo.

  15. Heterogeneous oxidation of carbonyl sulfide on mineral oxides

    Institute of Scientific and Technical Information of China (English)

    LIU YongChun; LIU JunFeng; HE Hong; YU YunBo; XUE Li

    2007-01-01

    Heterogeneous oxidation of carbonyl sulfide (OCS) on mineral oxides including SiO2, Fe2O3, CaO, MgO, ZnO and TiO2, which are the main components of atmospheric particles, were investigated using in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS), ion chromatography (IC), temperature-programmed desorption (TPD), X-ray diffraction (XRD) and Brunauer-Emmett-Teller (BET) methods. The main products and intermediates of the heterogeneous oxidation of OCS on these oxides were identified with in situ DRIFTS and IC. The reaction mechanism and kinetics were also discussed. It is found that the reaction mechanism on these mineral oxides is the same as that on Al2O3 for the same final products and the intermediates at room temperature. Namely, OCS can be catalytically oxidized to produce surface SO42- species and gaseous CO2 through the surface hydrogen thiocarbonate (HSCO2-) and HSO3- species. The activity series for heterogeneous oxidation of OCS follows: Al2O3 ≈ CaO>MgO>TiO2 ≈ ZnO>Fe2O3>SiO2. The specific area, basic hydroxyl and surface basicity of these oxides have effect on the reactivity. This study suggests that heterogeneous reactions of OCS on mineral dust may be an unneglectable sink of OCS.

  16. Hydrogen Sulfide Donor GYY4137 Protects against Myocardial Fibrosis

    Directory of Open Access Journals (Sweden)

    Guoliang Meng

    2015-01-01

    Full Text Available Hydrogen sulfide (H2S is a gasotransmitter which regulates multiple cardiovascular functions. However, the precise roles of H2S in modulating myocardial fibrosis in vivo and cardiac fibroblast proliferation in vitro remain unclear. We investigated the effect of GYY4137, a slow-releasing H2S donor, on myocardial fibrosis. Spontaneously hypertensive rats (SHR were administrated with GYY4137 by intraperitoneal injection daily for 4 weeks. GYY4137 decreased systolic blood pressure and inhibited myocardial fibrosis in SHR as evidenced by improved cardiac collagen volume fraction (CVF in the left ventricle (LV, ratio of perivascular collagen area (PVCA to lumen area (LA in perivascular regions, reduced hydroxyproline concentration, collagen I and III mRNA expression, and cross-linked collagen. GYY4137 also inhibited angiotensin II- (Ang II- induced neonatal rat cardiac fibroblast proliferation, reduced the number of fibroblasts in S phase, decreased collagen I and III mRNA expression and protein synthesis, attenuated oxidative stress, and suppressed α-smooth muscle actin (α-SMA, transforming growth factor-β1 (TGF-β1 expression as well as Smad2 phosphorylation. These results indicate that GYY4137 improves myocardial fibrosis perhaps by a mechanism involving inhibition of oxidative stress, blockade of the TGF-β1/Smad2 signaling pathway, and decrease in α-SMA expression in cardiac fibroblasts.

  17. Kinetics and mechanisms of hydrogen sulfide adsorption by biochars.

    Science.gov (United States)

    Shang, Guofeng; Shen, Guoqing; Liu, Liang; Chen, Qin; Xu, Zhiwei

    2013-04-01

    Three different biochars as cost-effective substitutes for activated carbon (AC) were tested for their hydrogen sulfide (H2S) adsorption ability. The biochars were produced from camphor (SC), bamboo (SB), and rice hull (SR) at 400°C by oxygen-limited pyrolysis. The surface area (SA), pH, and Fourier transform infrared spectras of the biochars and AC were compared. The maximum removal rates and the saturation constants were obtained using the Michaelis-Menten-type equation. The three biochars were found to be alkaline, and the SAs of the biochars were much smaller than that of the AC. The H2S breakthrough capacity was related to the local pH within the pore system of the biochar. The order observed in terms of both biochar and AC adsorption capacity was SR>SB>SC>AC. SR efficiently removed H2S within the inlet concentration range of 10-50 μL/L. Biochars derived from agricultural/forestry wastes are a promising H2S adsorbent with distinctive properties. PMID:23455220

  18. Physiological Importance of Hydrogen Sulfide: Emerging Potent Neuroprotector and Neuromodulator

    Science.gov (United States)

    Chung, Hyung-Joo

    2016-01-01

    Hydrogen sulfide (H2S) is an emerging neuromodulator that is considered to be a gasotransmitter similar to nitrogen oxide (NO) and carbon monoxide (CO). H2S exerts universal cytoprotective effects and acts as a defense mechanism in organisms ranging from bacteria to mammals. It is produced by the enzymes cystathionine β-synthase (CBS), cystathionine ϒ-lyase (CSE), 3-mercaptopyruvate sulfurtransferase (MST), and D-amino acid oxidase (DAO), which are also involved in tissue-specific biochemical pathways for H2S production in the human body. H2S exerts a wide range of pathological and physiological functions in the human body, from endocrine system and cellular longevity to hepatic protection and kidney function. Previous studies have shown that H2S plays important roles in peripheral nerve regeneration and degeneration and has significant value during Schwann cell dedifferentiation and proliferation but it is also associated with axonal degradation and the remyelination of Schwann cells. To date, physiological and toxic levels of H2S in the human body remain unclear and most of the mechanisms of action underlying the effects of H2S have yet to be fully elucidated. The primary purpose of this review was to provide an overview of the role of H2S in the human body and to describe its beneficial effects.

  19. The metallization and superconductivity of dense hydrogen sulfide

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yinwei, E-mail: yinwei-li@jsnu.edu.cn; Hao, Jian; Li, Yanling [School of Physics and Electronic Engineering, Jiangsu Normal University, Xuzhou 221116 (China); Liu, Hanyu [Department of Physics and Engineering Physics, University of Saskatchewan, Saskatchewan S7N 5E2 (Canada); Ma, Yanming, E-mail: mym@jlu.edu.cn [State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012 (China)

    2014-05-07

    Hydrogen sulfide (H{sub 2}S) is a prototype molecular system and a sister molecule of water (H{sub 2}O). The phase diagram of solid H{sub 2}S at high pressures remains largely unexplored arising from the challenges in dealing with the pressure-induced weakening of S–H bond and larger atomic core difference between H and S. Metallization is yet achieved for H{sub 2}O, but it was observed for H{sub 2}S above 96 GPa. However, the metallic structure of H{sub 2}S remains elusive, greatly impeding the understanding of its metallicity and the potential superconductivity. We have performed an extensive structural study on solid H{sub 2}S at pressure ranges of 10–200 GPa through an unbiased structure prediction method based on particle swarm optimization algorithm. Besides the findings of candidate structures for nonmetallic phases IV and V, we are able to establish stable metallic structures violating an earlier proposal of elemental decomposition into sulfur and hydrogen [R. Rousseau, M. Boero, M. Bernasconi, M. Parrinello, and K. Terakura, Phys. Rev. Lett. 85, 1254 (2000)]. Our study unravels a superconductive potential of metallic H{sub 2}S with an estimated maximal transition temperature of ∼80 K at 160 GPa, higher than those predicted for most archetypal hydrogen-containing compounds (e.g., SiH{sub 4}, GeH{sub 4}, etc.)

  20. Electrochemical characterization on cobalt sulfide for electrochemical supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Tao, Feng; Zhao, Yong-Qing; Zhang, Guo-Qing [College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000 (China); Li, Hu-Lin [College of Material Science and Engineering, Nanjing University of Aeronautics and Astronautisc, Nanjing 210013 (China); College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000 (China)

    2007-06-15

    High capacitance at a high charge-discharge current density of 50 mA/cm{sup 2} for a new type of electrochemical supercapacitor cobalt sulfide (CoS{sub x}) have been studied for the first time. The CoS{sub x} was prepared by a very simply chemical precipitation method. The electrochemical capacitance performance of this compound was investigated by cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge-discharge tests with a three-electrode system. The results show that CoS{sub x} has excellent electrochemical capacitive characteristic with potential range -0.3 {proportional_to} 0.35 V (versus SCE) in 6 M KOH solution. Charge-discharge behaviors have been observed with the highest specific capacitance values of 475 F/g at the current density of 5 mA/cm{sup 2}, even at the high current density of 50 mA/cm{sup 2}, CoS{sub x} also shows the high specific capacitance values of 369 F/g. (author)

  1. Seasonal fluxes of carbonyl sulfide in a midlatitude forest

    Science.gov (United States)

    Commane, Róisín; Meredith, Laura K.; Baker, Ian T.; Berry, Joseph A.; Munger, J. William; Montzka, Stephen A.; Templer, Pamela H.; Juice, Stephanie M.; Zahniser, Mark S.; Wofsy, Steven C.

    2015-11-01

    Carbonyl sulfide (OCS), the most abundant sulfur gas in the atmosphere, has a summer minimum associated with uptake by vegetation and soils, closely correlated with CO2. We report the first direct measurements to our knowledge of the ecosystem flux of OCS throughout an annual cycle, at a mixed temperate forest. The forest took up OCS during most of the growing season with an overall uptake of 1.36 ± 0.01 mol OCS per ha (43.5 ± 0.5 g S per ha, 95% confidence intervals) for the year. Daytime fluxes accounted for 72% of total uptake. Both soils and incompletely closed stomata in the canopy contributed to nighttime fluxes. Unexpected net OCS emission occurred during the warmest weeks in summer. Many requirements necessary to use fluxes of OCS as a simple estimate of photosynthesis were not met because OCS fluxes did not have a constant relationship with photosynthesis throughout an entire day or over the entire year. However, OCS fluxes provide a direct measure of ecosystem-scale stomatal conductance and mesophyll function, without relying on measures of soil evaporation or leaf temperature, and reveal previously unseen heterogeneity of forest canopy processes. Observations of OCS flux provide powerful, independent means to test and refine land surface and carbon cycle models at the ecosystem scale.

  2. Epithelial Electrolyte Transport Physiology and the Gasotransmitter Hydrogen Sulfide

    Science.gov (United States)

    Pouokam, Ervice; Althaus, Mike

    2016-01-01

    Hydrogen sulfide (H2S) is a well-known environmental chemical threat with an unpleasant smell of rotten eggs. Aside from the established toxic effects of high-dose H2S, research over the past decade revealed that cells endogenously produce small amounts of H2S with physiological functions. H2S has therefore been classified as a “gasotransmitter.” A major challenge for cells and tissues is the maintenance of low physiological concentrations of H2S in order to prevent potential toxicity. Epithelia of the respiratory and gastrointestinal tract are especially faced with this problem, since these barriers are predominantly exposed to exogenous H2S from environmental sources or sulfur-metabolising microbiota. In this paper, we review the cellular mechanisms by which epithelial cells maintain physiological, endogenous H2S concentrations. Furthermore, we suggest a concept by which epithelia use their electrolyte and liquid transport machinery as defence mechanisms in order to eliminate exogenous sources for potentially harmful H2S concentrations. PMID:26904165

  3. Physiological Importance of Hydrogen Sulfide: Emerging Potent Neuroprotector and Neuromodulator

    Science.gov (United States)

    Chung, Hyung-Joo

    2016-01-01

    Hydrogen sulfide (H2S) is an emerging neuromodulator that is considered to be a gasotransmitter similar to nitrogen oxide (NO) and carbon monoxide (CO). H2S exerts universal cytoprotective effects and acts as a defense mechanism in organisms ranging from bacteria to mammals. It is produced by the enzymes cystathionine β-synthase (CBS), cystathionine ϒ-lyase (CSE), 3-mercaptopyruvate sulfurtransferase (MST), and D-amino acid oxidase (DAO), which are also involved in tissue-specific biochemical pathways for H2S production in the human body. H2S exerts a wide range of pathological and physiological functions in the human body, from endocrine system and cellular longevity to hepatic protection and kidney function. Previous studies have shown that H2S plays important roles in peripheral nerve regeneration and degeneration and has significant value during Schwann cell dedifferentiation and proliferation but it is also associated with axonal degradation and the remyelination of Schwann cells. To date, physiological and toxic levels of H2S in the human body remain unclear and most of the mechanisms of action underlying the effects of H2S have yet to be fully elucidated. The primary purpose of this review was to provide an overview of the role of H2S in the human body and to describe its beneficial effects. PMID:27413423

  4. Discoveries of hydrogen sulfide as a novel cardiovascular therapeutic.

    Science.gov (United States)

    Barr, Larry A; Calvert, John W

    2014-01-01

    Hydrogen sulfide (H2S) is an endogenously produced gaseous signaling molecule that elicits a number of cytoprotective effects in mammalian species. H2S was originally considered toxic at elevated levels, but 15 years ago the labile molecule was discovered in mammalian tissue and termed a gasotransmitter, thus opening the door for research aimed towards understanding its physiologic nature. Since then, novel findings have depicted the beneficial aspects of H2S therapy, such as vasodilation, antioxidant upregulation, inflammation inhibition, and activation of anti-apoptotic pathways. These cytoprotective alterations effectively treat multiple forms of cardiac injury at the preclinical level of research. The field has progressed towards instituting novel H2S donors that prove more effective at activating the subsequent cardioprotective enhancements over longer time periods. As more findings explore the efficacy of H2S, research focused on detection of sulfhydrated targets is on the rise. Understanding the molecular mechanisms that stem from H2S treatment may lead the field towards powerful therapeutics in the clinical setting. This review will discuss the cytoprotective and cardioprotective effects of H2S therapy, provide analysis on the molecular alterations that lead to these enhancements, and explore recently developed therapeutics that may bring this gasotransmitter into the clinic in the near future.

  5. Trichosporon jirovecii-mediated synthesis of cadmium sulfide nanoparticles.

    Science.gov (United States)

    El-Baz, Ashraf Farag; Sorour, Noha Mohamed; Shetaia, Youssria Mohamed

    2016-05-01

    Cadmium sulphide is one of the most promising materials for solar cells and of great interest due to its useful applications in photonics and electronics, thus the development of bio-mediated synthesis of cadmium sulphide nanoparticles (CdS NPs) is one of the essential areas in nanoparticles. The present study demonstrates for the first time the eco-friendly biosynthesis of CdS NPs using the yeast Trichosporon jirovecii. The biosynthesis of CdS NPs were confirmed by UV-Vis spectrum and characterized by X-ray diffraction assay and electron microscopy. Scanning and transmission electron microscope analyses shows the formation of spherical CdS NPs with a size range of about 6-15 nm with a mean Cd:S molar ratio of 1.0:0.98. T. jirovecii produced hydrogen sulfide on cysteine containing medium confirmed by positive cysteine-desulfhydrase activity and the colony color turned yellow on 0.1 mM cadmium containing medium. T. jirovecii tolerance to cadmium was increased by the UV treatment and three 0.6 mM cadmium tolerant mutants were generated upon the UV radiation treatment. The overall results indicated that T. jirovecii could tolerate cadmium toxicity by its conversion into CdS NPs on cysteine containing medium using cysteine-desulfhydrase as a defense response mechanism. PMID:26467054

  6. Synthesis of actinide nitrides, phosphides, sulfides and oxides

    Science.gov (United States)

    Van Der Sluys, William G.; Burns, Carol J.; Smith, David C.

    1992-01-01

    A process of preparing an actinide compound of the formula An.sub.x Z.sub.y wherein An is an actinide metal atom selected from the group consisting of thorium, uranium, plutonium, neptunium, and americium, x is selected from the group consisting of one, two or three, Z is a main group element atom selected from the group consisting of nitrogen, phosphorus, oxygen and sulfur and y is selected from the group consisting of one, two, three or four, by admixing an actinide organometallic precursor wherein said actinide is selected from the group consisting of thorium, uranium, plutonium, neptunium, and americium, a suitable solvent and a protic Lewis base selected from the group consisting of ammonia, phosphine, hydrogen sulfide and water, at temperatures and for time sufficient to form an intermediate actinide complex, heating said intermediate actinide complex at temperatures and for time sufficient to form the actinide compound, and a process of depositing a thin film of such an actinide compound, e.g., uranium mononitride, by subliming an actinide organometallic precursor, e.g., a uranium amide precursor, in the presence of an effectgive amount of a protic Lewis base, e.g., ammonia, within a reactor at temperatures and for time sufficient to form a thin film of the actinide compound, are disclosed.

  7. Carbonyl Sulfide for Tracing Carbon Fluxes Field Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, J. Elliott [Univ. of California, Merced, CA (United States); Berry, Joseph A. [Carnegie Inst. of Science, Stanford, CA (United States); Billesbach, Dave [Univ. of Nebraska, Lincoln, NE (United States); Torn, Margaret S [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Zahniser, Mark [Aerodyne Research, Inc., Billerica, MA (United States); Seibt, Ulrike [Univ. of California, Los Angeles, CA (United States); Maseyk, Kadmiel [Pierre and Marie Curie Univ., Paris (France)

    2016-04-01

    The April-June 2012 campaign was located at the U.S. Department of Energy (DOE)’s Atmospheric Radiation Measurement (ARM) Climate Research Facility Southern Great Plains (SGP) site Central Facility and had three purposes. One goal was to demonstrate the ability of current instrumentation to correctly measure fluxes of atmospheric carbonyl sulfide (COS). The approach has been describe previously as a critical approach to advancing carbon cycle science1,2, but requires further investigation at the canopy scale to resolve ecosystem processes. Previous canopy-scale efforts were limited to data rates of 1Hz. While 1 Hz measurements may work in a few ecosystems, it is widely accepted that data rates of 10 to 20 Hz are needed to fully capture the exchange of traces gases between the atmosphere and vegetative canopy. A second goal of this campaign was to determine if canopy observations could provide information to help interpret the seasonal double peak in airborne observations at SGP of CO2 and COS mixing ratios. A third goal was to detect potential sources and sinks of COS that must be resolved before using COS as a tracer of gross primary productivity (GPP).

  8. Hydrothermal sulfide accumulation along the Endeavour Segment, Juan de Fuca Ridge

    Science.gov (United States)

    Jamieson, J. W.; Clague, D. A.; Hannington, M. D.

    2014-06-01

    Hydrothermal sulfide deposits that form on the seafloor are often located by the detection of hydrothermal plumes in the water column, followed by exploration with deep-towed cameras, side-scan sonar imaging, and finally by visual surveys using remotely-operated vehicle or occupied submersible. Hydrothermal plume detection, however, is ineffective for finding hydrothermally-inactive sulfide deposits, which may represent a significant amount of the total sulfide accumulation on the seafloor, even in hydrothermally active settings. Here, we present results from recent high-resolution, autonomous underwater vehicle-based mapping of the hydrothermally-active Endeavour Segment of the Juan de Fuca Ridge, in the Northeast Pacific Ocean. Analysis of the ridge bathymetry resulted in the location of 581 individual sulfide deposits along 24 km of ridge length. Hydrothermal deposits were distinguished from volcanic and tectonic features based on the characteristics of their surface morphology, such as shape and slope angles. Volume calculations for each deposit results in a total volume of 372,500 m3 of hydrothermal sulfide-sulfate-silica material, for an equivalent mass of ∼1.2 Mt of hydrothermal material on the seafloor within the ridge's axial valley, assuming a density of 3.1 g/cm3. Much of this total volume is from previously undocumented inactive deposits outside the main active vent fields. Based on minimum ages of sulfide deposition, the deposits accumulated at a maximum rate of ∼400 t/yr, with a depositional efficiency (proportion of hydrothermal material that accumulates on the seafloor to the total amount hydrothermally mobilized and transported to the seafloor) of ∼5%. The calculated sulfide tonnage represents a four-fold increase over previous sulfide estimates for the Endeavour Segment that were based largely on accumulations from within the active fields. These results suggest that recent global seafloor sulfide resource estimates, which were based mostly

  9. Antifoaming materials studies in G.S. (Girlder sulfide) heavy water plants. Chemical and thermical stability. Pt. 3

    International Nuclear Information System (INIS)

    In Girlder sulfide (G.S.) heavy water plants hydrogen sulfide-water systems are inherentely foaming, so the adding of antifoaming materials is of great importance. These may be of high volatility, pyrolizable or chemically unstable in plant operation conditions (water and hydrogen sulfide at 2 MPa, up to 230 deg C). Five commercial surfactants were studied from the point of view of their chemical and thermical stability in order to select the most suitable. (Author)

  10. The effect of sulfide dissolved in silicate melts on enhancing the solubility of the Highly Siderophile Elements

    Science.gov (United States)

    O'Neill, H. S.

    2015-12-01

    There are large inconsistencies among experimental studies of Highly Siderophile Element (HSE) partitioning relations between silicates and metal or sulfide phases, which has usually been attributed to "micronuggets", a general term for sub-optical (approximately HSE sulfide-melt/silicate-melt partition coefficients, where results range over several orders of magnitude. Moreover, nearly all the reported results of directly determined sulfide-melt/silicate-melt partition coefficients are considerably lower than values calculated by combining metal/silicate-melt with metal/sulfide-melt partition coefficients. This discrepancy has been attributed to large effects of S dissolved as sulfide in the silicate melts on HSE solubilities. As such large effects are not expected from the thermodynamic modeling of sulfide solubilities in silicate melts, it has been proposed that HSEs dissolve in sulfide-containing silicate melts by forming HSE-S complexes. This idea has been tested by experiments that compare the solubilities of Ir, Re and Ru in a high-TiO2 silicate melt both with and without dissolved sulfide at 1400 to 1600ºC at atmospheric pressure. The high TiO2 suppresses micronuggets. Experiments were analysed by LA-ICP-MS, with detection limits approaching 2 ppb. For Ir, the results show that at fO2 low enough to enable measurable sulfide in the melt, the presence of the sulfide just raises the level of dissolved Ir above detection limits. These results suggest a fairly large influence of the sulfide, but are not quantitative. By contrast, the experiments on Ru and Re clearly show only a modest effect of dissolved sulfide.

  11. Studies on silicone based antifoaming agents to be used in G.S. (Girlder sulfide) heavy water plants

    International Nuclear Information System (INIS)

    In Girlder sulfide (G.S.) heavy water plants hydrogen sulfide-water systems are inherentely foaming, so the adding of antifoaming materials is of great importance. These may be of high volatility, pyrolizable or chemically unstable in plant operation conditions (water and hydrogen sulfide at 2MPa, up to 230 deg C). Six commercial silicone based antifoaming agents were studied from the point of view of their chemical and thermical stability in order to select the most suitable. (Author)

  12. Catalysis of Dissolved and Adsorbed Iron in Soil Suspension for Chromium(Ⅵ) Reduction by Sulfide

    Institute of Scientific and Technical Information of China (English)

    LAN Ye-Qing; YANG Jun-Xiang; B. DENG

    2006-01-01

    The kinetics of Cr(Ⅵ) reduction by sulfide in soil suspensions with various pHs, soil compositions, and Fe(Ⅱ) concentrations was examined using batch anaerobic experimental systems at constant temperature. The results showed that the reaction rate of Cr(Ⅵ) reduction was in the order of red soil < yellow-brown soil < chernozem and was proportional to the concentration of HCl-extractable iron in the soils. Dissolved and adsorbed iron in soil suspensions played an important role in accelerating Cr(Ⅵ) reduction. The reaction involved in the Cr(Ⅵ) reduction by Fe(Ⅱ) to produce Fe(Ⅲ), which was reduced to Fe(Ⅱ) again by sulfide, could represent the catalytic pathway until about 70% of the initially present Cr(Ⅵ)was reduced. The catalysis occurred because the one-step reduction of Cr(Ⅵ) by sulfide was slower than the two-step process consisting of rapid Cr(Ⅵ) reduction by Fe(Ⅱ) followed by Fe(Ⅲ) reduction by sulfide. In essence, Fe(Ⅱ)/Fe(Ⅲ)species shuttle electrons from sulfide to Cr(Ⅵ), facilitating the reaction. The effect of iron, however, could be completely blocked by adding a strong Fe(Ⅱ)-complexing ligand, 1,10-phenanthroline, to the soil suspensions. In all the experiments,initial sulfide concentration was much higher than initial Cr(Ⅵ) concentration. The plots of ln c[Cr(Ⅵ)] versus reaction time were linear up to approximately 70% of Cr(Ⅵ) reduction, suggesting a first-order reaction kinetics with respect to Cr(Ⅵ). Elemental sulfur, the product of sulfide oxidation, was found to accelerate Cr(Ⅵ) reduction at a later stage of the reaction, resulting in deviation from linearity for the ln c[Cr(Ⅵ)] versus time plots.

  13. Photolytic Decomposition Of Hydrogen Sulfide In The Gas Mixtures And Formation Of Molecular Hydrogen

    International Nuclear Information System (INIS)

    Full text : The chemical conversions of organic fuels during the refining processes complex gas mixtures containing hydrogen sulfide generate as a by-product. In accordance with the environmental safety requirements these gas mixtures have to be purified from hydrogen sulfide before use or environmental discharge. As it is known because of combustion gases containing hydrogen-sulfide oxides of sulfide emit into the atmosphere and they combine with water vapors in the air and this process consequently results in pH change of H2SO3 precipitations and acid rains. The processes of purification of gas mixtures being the product of oil refining processes and mainly containing hydrocarbons from hydrogen sulfide by a photochemical method and molecular hydrogen generation have been under this investigation.The model gas mixture under investigation has been prepared at a vacuum plant in the laboratory. During the researches the partial pressure of H2S capable of completely absorbing the given wave-length of the radiation has been first specified. It has been established that temperature and irradiation time have their influence on the progress rate of the processes.At this wave-length hydrocarbons undergo no photochemical conversions. This is manifested with the absence of excitation levels causing dissociation due to radiation absorption at the wave-length used in hydrocarbon gases . The fact that these levels belong to hydrogen sulfide contained in gas mixtures has been experimentally proved.The role of hot hydrogen atoms and the mechanism of the processes under progress within the process of molecular hydrogen generation due to the photolytic decomposition of hydrogen sulfide have been discussed.

  14. Adsorption of dimethyl sulfide from aqueous solution by a cost-effective bamboo charcoal.

    Science.gov (United States)

    Wang, Ming; Huang, Zheng-Hong; Liu, Guangjia; Kang, Feiyu

    2011-06-15

    The adsorption of dimethyl sulfide from an aqueous solution by a cost-effective bamboo charcoal from Dendrocalamus was studied in comparison with other carbon adsorbents. The bamboo charcoal exhibited superior adsorption on dimethyl sulfide compared with powdered activated carbons at different adsorbent dosages. The adsorption characteristics of dimethyl sulfide onto bamboo charcoal were investigated under varying experimental conditions such as particle size, contact time, initial concentration and adsorbent dosage. The dimethyl sulfide removal was enhanced from 31 to 63% as the particle size was decreased from 24-40 to >300 mesh for the bamboo charcoal. The removal efficiency increased with increasing the adsorbent dosage from 0.5 to 10mg, and reached 70% removal efficiency at 10mg adsorbed. The adsorption capacity (μg/g) increased with increasing concentration of dimethyl sulfide while the removal efficiency decreased. The adsorption process conforms well to a pseudo-second-order kinetics model. The adsorption of dimethyl sulfide is more appropriately described by the Freundlich isotherm (R(2), 0.9926) than by the Langmuir isotherm (R(2), 0.8685). Bamboo charcoal was characterized by various analytical methods to understand the adsorption mechanism. Bamboo charcoal is abundant in acidic and alcohol functional groups normally not observed in PAC. A distinct difference is that the superior mineral composition of Fe (0.4 wt%) and Mn (0.6 wt%) was detected in bamboo charcoal-elements not found in PAC. Acidic functional group and specific adsorption sites would be responsible for the strong adsorption of dimethyl sulfide onto bamboo charcoal of Dendrocalamus origin. PMID:21549503

  15. Density Functional Investigation of Methanethiol and Dimethyl Sulfide Adsorption on Zeolite

    Institute of Scientific and Technical Information of China (English)

    Renqing Lü; Guangmin Qiu; Chenguang Liu

    2006-01-01

    The density functional theory and cluster model methods have been employed to investigate the interactions between methanethiol, dimethyl sulfide and zeolites. The molecular complexes formed by adsorption of methanethiol or dimethyl sulfide on silanol H3SiOSi(OH)2OSiH3 with five coordination forms or four coordination forms, and complexes formed by interactions of Br(o)nsted acid sites of bridging hydroxyl H3Si(OH)Al(OH)2OSiH3 with methanethiol or dimethyl sulfide have been investigated. Full optimization and frequency analysis of all cluster models have been carried out using the B3LYP hybrid method at 6-31+G (d,p) basis set level for hydrogen, silicon, aluminum, oxygen,carbon, and sulfur atoms. The structures and energy changes of different coordination forms between methanethiol and H3Si(OH)Al(OH)2OSiH3, dimethyl sulfide and H3Si(OH)Al(OH)2OSiH3, methanethiol and H3SiOSi(OH)2OSiH3, dimethyl sulfide and H3SiOSi(OH)2OSiH3 complexes have been comparatively studied. The calculated results showed the nature of interactions that led to the formation of all complexes was van der Waals force confirmed by an insignificant change of geometric structures and properties. The conclusions that methanethiol and dimethyl sulfide molecules were adsorbed on bridging hydroxyl group prior to silanol group were obtained on the basis of adsorption heat, the most stable adsorption models of a 6 ring structure for interaction between bridging hydroxyl and methanethiol, and a 7 ring structure for interaction between bridging hydroxyl and dimethyl sulfide.

  16. Transformation of iron sulfide to greigite by nitrite produced by oil field bacteria.

    Science.gov (United States)

    Lin, Shiping; Krause, Federico; Voordouw, Gerrit

    2009-05-01

    Nitrate, injected into oil fields, can oxidize sulfide formed by sulfate-reducing bacteria (SRB) through the action of nitrate-reducing sulfide-oxidizing bacteria (NR-SOB). When reservoir rock contains siderite (FeCO(3)), the sulfide formed is immobilized as iron sulfide minerals, e.g. mackinawite (FeS). The aim of our study was to determine the extent to which oil field NR-SOB can oxidize or transform FeS. Because no NR-SOB capable of growth with FeS were isolated, the well-characterized oil field isolate Sulfurimonas sp. strain CVO was used. When strain CVO was presented with a mixture of chemically formed FeS and dissolved sulfide (HS(-)), it only oxidized the HS(-). The FeS remained acid soluble and non-magnetic indicating that it was not transformed. In contrast, when the FeS was formed by adding FeCl(2) to a culture of SRB which gradually produced sulfide, precipitating FeS, and to which strain CVO and nitrate were subsequently added, transformation of the FeS to a magnetic, less acid-soluble form was observed. X-ray diffraction and energy-dispersive spectrometry indicated the transformed mineral to be greigite (Fe(3)S(4)). Addition of nitrite to cultures of SRB, containing microbially formed FeS, was similarly effective. Nitrite reacts chemically with HS(-) to form polysulfide and sulfur (S(0)), which then transforms SRB-formed FeS to greigite, possibly via a sulfur addition pathway (3FeS + S(0) --> Fe(3)S(4)). Further chemical transformation to pyrite (FeS(2)) is expected at higher temperatures (>60 degrees C). Hence, nitrate injection into oil fields may lead to NR-SOB-mediated and chemical mineral transformations, increasing the sulfide-binding capacity of reservoir rock. Because of mineral volume decreases, these transformations may also increase reservoir injectivity. PMID:19290520

  17. Zinc sulfide and terbium-doped zinc sulfide films grown by traveling wave reactor atomic layer epitaxy

    CERN Document Server

    Yun, S J; Nam, K S

    1998-01-01

    Zinc sulfide (ZnS) and terbium-doped ZnS (ZnS:Tb) thin films were grown by traveling wave reactor atomic layer epitaxy (ALE). In the present work, ZnCl sub 2 , H sub 2 S, and tris (2,2,6,6-tetramethyl-3,5-heptandionato) terbium (Tb(tmhd) sub 3) were used as the precursors. The dependence of crystallinity and Cl content of ZnS films was investigated on the growth temperature. ZnS and ZnS:Tb films grown at temperatures ranging from 400 to 500 .deg. C showed a hexagonal-2H crystalline structure. The crystallinity of ZnS film was greatly enhanced as the temperature increased. At growth temperatures higher than 450.deg.C, the films showed preferred orientation with mainly (002) diffraction peak. The Cl content decreased from approximately 9 to 1 at.% with the increase in growth temperature from 400 to 500 .deg. C. The segregation of Cl near the surface region and the incorporation of O from Tb(tmhd) sub 3 during ALE process were also observed using Auger electron spectroscopy. The ALE-grown ZnS and ZnS:Tb films re...

  18. Tellurium-bearing minerals in zoned sulfide chimneys from Cu-Zn massive sulfide deposits of the Urals, Russia

    Science.gov (United States)

    Maslennikov, V. V.; Maslennikova, S. P.; Large, R. R.; Danyushevsky, L. V.; Herrington, R. J.; Stanley, C. J.

    2013-02-01

    Tellurium-bearing minerals are generally rare in chimney material from mafic and bimodal felsic volcanic hosted massive sulfide (VMS) deposits, but are abundant in chimneys of the Urals VMS deposits located within Silurian and Devonian bimodal mafic sequences. High physicochemical gradients during chimney growth result in a wide range of telluride and sulfoarsenide assemblages including a variety of Cu-Ag-Te-S and Ag-Pb-Bi-Te solid solution series and tellurium sulfosalts. A change in chimney types from Fe-Cu to Cu-Zn-Fe to Zn-Cu is accompanied by gradual replacement of abundant Fe-, Co, Bi-, and Pb- tellurides by Hg, Ag, Au-Ag telluride and galena-fahlore with native gold assemblages. Decreasing amounts of pyrite, both colloform and pseudomorphic after pyrrhotite, isocubanite ISS and chalcopyrite in the chimneys is coupled with increasing amounts of sphalerite, quatz, barite or talc contents. This trend represents a transition from low- to high sulphidation conditions, and it is observed across a range of the Urals deposits from bimodal mafic- to bimodal felsic-hosted types: Yaman-Kasy → Molodezhnoye → Uzelga → Valentorskoye → Oktyabrskoye → Alexandrinskoye → Tash-Tau → Jusa.

  19. The changes of three components in coelomic fluid of Urechis unicinctus exposed to different concentrations of sulfide

    Institute of Scientific and Technical Information of China (English)

    MA Zhuojun; BAO Zhenmin; KANG Kyoung-Ho; YU Li; ZHANG Zhifeng

    2005-01-01

    The changes in heme (associated with hemoglobin), hemoglobin and hematin in the coelomic fluid of marine worm, Urechis unicinctus, exposed to different concentrations of sulfide, were investigated using biochemical techniques. When exposed to different sulfide concentrations for up to 96 h, the relative amounts of the three components changed in a regular pattern suggesting that the coelomocytes play an important role in the worm's tolerance to sulfide. The possible roles of heme compounds in sulfide tolerance of this species are discussed on the basis of our experimental data.

  20. Bacterial leaching of metal sulfides proceeds by two indirect mechanisms via thiosulfate or via polysulfides and sulfur

    Energy Technology Data Exchange (ETDEWEB)

    Schippers, A.; Sand, W. [Univ. Hamburg (Germany). Inst. fuer Allgemeine Botanik

    1999-01-01

    Bacterial leaching, the biooxidation of metal sulfides to soluble metal sulfates and sulfuric acid, is effected by specialized bacteria. The acid-insoluble metal sulfides FeS{sub 2}, MoS{sub 2}, and WS{sub 2} are chemically attacked by iron(III) hexahydrate ions, generating thiosulfate, which is oxidized to sulfuric acid. Other metal sulfides are attacked by iron(III) ions and by protons, resulting in the formation of elemental sulfur via intermediary polysulfides. Sulfur is biooxidized to sulfuric acid. This explains leaching of metal sulfides by Thiobacillus thiooxidans.

  1. Use of bauxite residue (red mud) as a low cost sorbent for sulfide removal in polluted water remediation.

    Science.gov (United States)

    Sheng, Yanqing; Sun, Qiyao; Sun, Ruichuan; Burke, Ian T; Mortimer, Robert J G

    2016-01-01

    Sulfide is an important pollutant in aqueous systems. Sulfide removal from polluted waters is required prior to discharge. Red mud (RM) is a solid waste of bauxite processing that is rich in reactive iron oxides and consequently has the potential to be used to remove sulfide from aqueous systems. A series of experiments was undertaken using raw and sintered RM to remove sulfide from waters. RM was highly efficient at sulfide removal (average 75% sulfide removal at initial concentration of ∼5 mg L(-1), with 500 mg L(-1) RM addition) due to both physical adsorption (high specific area) and chemical reaction (with amorphous Fe). Sintered RM, which has a lower surface area and lower mineral reactivity, was much less efficient at removing sulfide (∼20% removal under equivalent experimental conditions). Furthermore, concomitant metal release from raw RM was lower than for sintered RM during the sulfide removal process. The results showed that raw RM is a potentially suitable material for sulfide removal from polluted waters and consequently could be used as a low cost alternative treatment in certain engineering applications. PMID:27438240

  2. Use of ferric sulfate: acid media for the desulfurization of model compounds of coal. [Dibenzothiophene, diphenyl sulfide, di-n-butyl sulfide

    Energy Technology Data Exchange (ETDEWEB)

    Clary, L.R.; Vermeulen, T.; Lynn, S.

    1980-12-01

    The objective of this work has been to investigate the ability of ferric sulfate-acid leach systems to oxidize the sulfur in model compounds of coal. Ferric iron-acid leach systems have been shown to be quite effective at removal of inorganic sulfur in coal. In this study, the oxidative effect of ferric iron in acid-leach systems was studied using dibenzothiophene, diphenyl sulfide, and di-n-butyl sulfide as models of organic sulfur groups in coal. Nitrogen and oxygen, as well as various transition metal catalysts and oxidants, were utilized in this investigation. Dibenzothiophene was found to be quite refractory to oxidation, except in the case where metavanadate was added, where it appears that 40% oxidation to sulfone could have occurred per hour at 150/sup 0/C and mild oxygen pressure. Diphenyl sulfide was selectively oxidized to sulfoxide and sulfone in an iron and oxygen system. Approximately 15% conversion to sulfone occurred per hour under these conditions. Some of the di-n-butyl sulfide was cracked to 1-butene and 1-butanethiol under similar conditions. Zinc chloride and ferric iron were used at 200/sup 0/C in an attempt to desulfonate dibenzothiophene sulfone, diphenyl sulfone, and di-n-butyl sulfone. Di-n-butyl sulfone was completely desulfurized on one hour and fragmented to oxidized parafins, while dibenzothiophene sulfone and diphenyl sulfone were unaffected. These results suggest that an iron-acid leach process could only selectively oxidize aryl sulfides under mild conditions, representing only 20% of the organic sulfur in coal (8% of the total sulfur). Removal through desulfonation once selective sulfur oxidation had occurred was only demonstrated for alkyl sulfones, with severe oxidation of the fragmented paraffins also occurring in one hour.

  3. Hydrogen sulfide improves neural function in rats following cardiopulmonary resuscitation

    Science.gov (United States)

    LIN, JI-YAN; ZHANG, MIN-WEI; WANG, JIN-GAO; LI, HUI; WEI, HONG-YAN; LIU, RONG; DAI, GANG; LIAO, XIAO-XING

    2016-01-01

    The alleviation of brain injury is a key issue following cardiopulmonary resuscitation (CPR). Hydrogen sulfide (H2S) is hypothesized to be involved in the pathophysiological process of ischemia-reperfusion injury, and exerts a protective effect on neurons. The aim of the present study was to investigate the effects of H2S on neural functions following cardiac arrest (CA) in rats. A total of 60 rats were allocated at random into three groups. CA was induced to establish the model and CPR was performed after 6 min. Subsequently, sodium hydrosulfide (NaHS), hydroxylamine or saline was administered to the rats. Serum levels of H2S, neuron-specific enolase (NSE) and S100β were determined following CPR. In addition, neurological deficit scoring (NDS), the beam walking test (BWT), prehensile traction test and Morris water maze experiment were conducted. Neuronal apoptosis rates were detected in the hippocampal region following sacrifice. After CPR, as the H2S levels increased or decreased, the serum NSE and S100β concentrations decreased or increased, respectively (P<0.0w. The NDS results of the NaHS group were improved compared with those of the hydroxylamine group at 24 h after CPR (P<0.05). In the Morris water maze experiment, BWT and prehensile traction test the animals in the NaHS group performed best and rats in the hydroxylamine group performed worst. At day 7, the apoptotic index and the expression of caspase-3 were reduced in the hippocampal CA1 region, while the expression of Bcl-2 increased in the NaHS group; and results of the hydroxylamine group were in contrast. Therefore, the results of the present study indicate that H2S is able to improve neural function in rats following CPR. PMID:26893650

  4. Electrophysiological effects of hydrogen sulfide on human atrial fibers

    Institute of Scientific and Technical Information of China (English)

    XU Meng; WU Yu-ming; LI Qian; LIU Su; HE Rui-rong

    2011-01-01

    Background It has been reported that endogenous or exogenous hydrogen sulfide (H2S) exerts physiological effects in the vertebrate cardiovascular system.We have also demonstrated that H2S acts as an important regulator of electrophysiological properties in guinea pig papillary muscles and on pacemaker cells in sinoatrial nodes of rabbits.This study was to observe the electrophysiological effects of H2S on human atrial fibers.Methods Human atrial samples were collected during cardiac surgery.Parameters of action potential in human atrial specialized fibers were recorded using a standard intracellular microelectrode technique.Results NaHS (H2S donor) (50,100 and 200 μmol/L) decreased the amplitude of action potential (APA),maximal rate of depolarization (Vmax),velocity of diastolic (phase 4) depolarization (VDD) and rate of pacemaker firing (RPF),and shortened the duration of 90% repolarization (APD90) in a concentration-dependent manner.ATP-sensitive K+ (KATP)channel blocker glibenclamide (Gli,20 μmol/L) partially blocked the effects of NaHS (100 μmol/L) on human atrial fiber cells.The L-type Ca2+ channel agonist Bay K8644 (0.5 μmol/L) also partially blocked the effects of NaHS (100 μmol/L).An inhibitor of cystathionine y-lyase (CSE),DL-propargylglycine (PPG,200 μmol/L),increased APA,Vmax,VDD and RPF,and prolonged APD90.Conclusions H2S exerts a negative chronotropic action and accelerates the repolarization of human atrial specialized fibers,possibly as a result of increases in potassium efflux through the opening of KATP channels and a concomitant decrease in calcium influx.Endogenous H2S may be generated by CSE and act as an important regulator of electrophysiological properties in human atrial fibers.

  5. The global transcriptional response of fission yeast to hydrogen sulfide.

    Directory of Open Access Journals (Sweden)

    Xu Jia

    Full Text Available BACKGROUND: Hydrogen sulfide (H(2S is a newly identified member of the small family of gasotransmitters that are endogenous gaseous signaling molecules that have a fundamental role in human biology and disease. Although it is a relatively recent discovery and the mechanism of H(2S activity is not completely understood, it is known to be involved in a number of cellular processes; H(2S can affect ion channels, transcription factors and protein kinases in mammals. METHODOLOGY/PRINCIPAL FINDINGS: In this paper, we have used fission yeast as a model organism to study the global gene expression profile in response to H(2S by microarray. We initially measured the genome-wide transcriptional response of fission yeast to H(2S. Through the functional classification of genes whose expression profile changed in response to H(2S, we found that H(2S mainly influences genes that encode putative or known stress proteins, membrane transporters, cell cycle/meiotic proteins, transcription factors and respiration protein in the mitochondrion. Our analysis showed that there was a significant overlap between the genes affected by H(2S and the stress response. We identified that the target genes of the MAPK pathway respond to H(2S; we also identified that a number of transporters respond to H(2S, these include sugar/carbohydrate transporters, ion transporters, and amino acid transporters. We found many mitochondrial genes to be down regulated upon H(2S treatment and that H(2S can reduce mitochondrial oxygen consumption. CONCLUSION/SIGNIFICANCE: This study identifies potential molecular targets of the signaling molecule H(2S in fission yeast and provides clues about the identity of homologues human proteins and will further the understanding of the cellular role of H(2S in human diseases.

  6. Arsenic Sulfide Nanowire Formation on Fused Quartz Surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Olmstead, J.; Riley, B.J.; Johnson, B.R.; Sundaram, S.K.

    2005-01-01

    Arsenic sulfide (AsxSy) nanowires were synthesized by an evaporation-condensation process in evacuated fused quartz ampoules. During the deposition process, a thin, colored film of AsxSy was deposited along the upper, cooler portion of the ampoule. The ampoule was sectioned and the deposited film analyzed using scanning electron microscopy (SEM) to characterize and semi-quantitatively evaluate the microstructural features of the deposited film. A variety of microstructures were observed that ranged from a continuous thin film (warmer portion of the ampoule), to isolated micron- and nano-scale droplets (in the intermediate portion), as well as nanowires (colder portion of the ampoule). Experiments were conducted to evaluate the effects of ampoule cleaning methods (e.g. modify surface chemistry) and quantity of source material on nanowire formation. The evolution of these microstructures in the thin film was determined to be a function of initial pressure, substrate temperature, substrate surface treatment, and initial volume of As2S3 glass. In a set of two experiments where the initial pressure, substrate thermal gradient, and surface treatment were the same, the initial quantity of As2S3 glass per internal ampoule volume was doubled from one test to the other. The results showed that AsxSy nanowires were only formed in the test with the greater initial quantity of As2S3 per internal ampoule volume. The growth data for variation in diameter (e.g. nanowire or droplet) as a function of substrate temperature was fit to an exponential trendline with the form y = Aekx, where y is the structure diameter, A = 1.25×10-3, k = 3.96×10-2, and x is the temperature with correlation coefficient, R2 = 0.979, indicating a thermally-activated process.

  7. HYDROGEN SULFIDE ADSORPTION BY ALKALINE IMPREGNATED COCONUT SHELL ACTIVATED CARBON

    Directory of Open Access Journals (Sweden)

    HUI SUN CHOO

    2013-12-01

    Full Text Available Biogas is one type of renewable energy which can be burnt to produce heat and electricity. However, it cannot be burnt directly due to the presence of hydrogen sulfide (H2S which is highly corrosive to gas engine. In this study, coconut shell activated carbon (CSAC was applied as a porous adsorbent for H2S removal. The effect of amount of activated carbon and flow rate of gas stream toward adsorption capacity were investigated. Then, the activated carbons were impregnated by three types of alkaline (NaOH, KOH and K2CO3 with various ratios. The effects of various types of alkaline and their impregnation ratio towards adsorption capacity were analysed. In addition, H2S influent concentration and the reaction temperature on H2S adsorption were also investigated. The result indicated that adsorption capacity increases with the amount of activated carbon and decreases with flow rate of gas stream. Alkaline impregnated activated carbons had better performance than unimpregnated activated carbon. Among all impregnated activated carbons, activated carbon impregnated by K2CO3 with ratio 2.0 gave the highest adsorption capacity. Its adsorption capacity was 25 times higher than unimpregnated activated carbon. The result also indicated that the adsorption capacity of impregnated activated carbon decreased with the increment of H2S influent concentration. Optimum temperature for H2S adsorption was found to be 50˚C. In this study, the adsorption of H2S on K2CO3 impregnated activated carbon was fitted to the Langmuir isotherm. The fresh and spent K2CO3 impregnated activated carbon were characterized to study the adsorption process.

  8. Soil fluxes of carbonyl sulfide (COS) across four distinct ecosystems

    Science.gov (United States)

    Sun, W.; Maseyk, K. S.; Lett, C.; Juarez, S.; Kooijmans, L.; Mammarella, I.; Vesala, T.; Chen, H.; Seibt, U.

    2015-12-01

    Soils are additional but poorly resolved sinks of carbonyl sulfide (COS) in terrestrial ecosystems. COS has been proposed as a tracer for quantifying gross photosynthesis based on the coupled stomatal uptake of COS and CO2. But applying this tracer requires the soil COS flux to be subtracted from the ecosystem flux to obtain the actual plant flux. To simulate soil COS fluxes, we have built a 1-D diffusion-reaction model accounting for vertical transport in the soil, microbial sinks and sources, and a litter layer. Uptake and production of COS in the soil column are linked with soil temperature and moisture through empirical functions adapted from enzyme kinetics and lab incubations. We have measured soil COS fluxes and the related soil variables in four distinct ecosystems: a wheat field (Southern Great Plains, OK, USA), an oak woodland (Santa Monica Mountains, CA, USA), a tropical rainforest (La Selva Biological Station, Costa Rica) and a boreal pine forest (Hyytiälä, Finland). Across all sites, a lower soil temperature and a humid climate are generally favorable to soil COS uptake. Strong COS emissions were observed in the wheat field at high soil temperatures after harvesting but were absent in other ecosystems, indicating that COS exchange may behave differently in agricultural soils. We simulated the soil fluxes in all ecosystems using the diffusion-reaction model, and optimized the source/sink strength parameters with field data. The optimized model provides insights that are not attainable from data analysis alone: For example, the wheat field soil must have continued uptake activity even when it showed net emissions, and leaf litter contributed dominantly to the COS sink after rain in the oak woodland. We expect the new model to be useful for simulating global soil COS fluxes as field data on soil fluxes from a broader range of ecosystems become available.

  9. The Role of Hydrogen Sulfide in Renal System

    Science.gov (United States)

    Cao, Xu; Bian, Jin-Song

    2016-01-01

    Hydrogen sulfide has gained recognition as the third gaseous signaling molecule after nitric oxide and carbon monoxide. This review surveys the emerging role of H2S in mammalian renal system, with emphasis on both renal physiology and diseases. H2S is produced redundantly by four pathways in kidney, indicating the abundance of this gaseous molecule in the organ. In physiological conditions, H2S was found to regulate the excretory function of the kidney possibly by the inhibitory effect on sodium transporters on renal tubular cells. Likewise, it also influences the release of renin from juxtaglomerular cells and thereby modulates blood pressure. A possible role of H2S as an oxygen sensor has also been discussed, especially at renal medulla. Alternation of H2S level has been implicated in various pathological conditions such as renal ischemia/reperfusion, obstructive nephropathy, diabetic nephropathy, and hypertensive nephropathy. Moreover, H2S donors exhibit broad beneficial effects in renal diseases although a few conflicts need to be resolved. Further research reveals that multiple mechanisms are underlying the protective effects of H2S, including anti-inflammation, anti-oxidation, and anti-apoptosis. In the review, several research directions are also proposed including the role of mitochondrial H2S in renal diseases, H2S delivery to kidney by targeting D-amino acid oxidase/3-mercaptopyruvate sulfurtransferase (DAO/3-MST) pathway, effect of drug-like H2S donors in kidney diseases and understanding the molecular mechanism of H2S. The completion of the studies in these directions will not only improves our understanding of renal H2S functions but may also be critical to translate H2S to be a new therapy for renal diseases.

  10. Oxygen and sulfur isotope fractionation during sulfide oxidation by anoxygenic phototrophic bacteria

    Science.gov (United States)

    Brabec, Michelle Y.; Lyons, Timothy W.; Mandernack, Kevin W.

    2012-04-01

    Sulfide-mediated anoxygenic photosynthesis (SMAP) carried out by anaerobic phototrophic bacteria may have played an important role in sulfur cycling, formation of sulfate, and, perhaps, primary production in the Earth’s early oceans. Determination of ε34SSO4-Sulfide- and ε18OSO4-H2O values for bacterial sulfide oxidation will permit more refined interpretation of the δ34S and δ18OSO4 values measured in modern anoxic environments, such as meromictic lakes where sulfide commonly extends into the photic zone, and in the ancient rock record, particularly during periods of the Precambrian when anoxic and sulfidic (euxinic) conditions were believed to be more pervasive than today. Laboratory experiments with anaerobic purple and green sulfur phototrophs, Allochromatium vinosum and Chlorobaculum tepidum, respectively, were conducted to determine the sulfur and oxygen isotope fractionation during the oxidation of sulfide to sulfate. Replicate experiments were conducted at 25 °C for A. vinosum and 45 °C for C. tepidum, and in duplicate at three different starting oxygen isotope values for water to determine sulfate-water oxygen isotope fractionations accurately (ε18OSO4-H2O). ε18OSO4-H2O values of 5.6 ± 0.2‰ and 5.4 ± 0.1‰ were obtained for A. vinosum and C. tepidum, respectively. Temperature had no apparent effect on the ε18OSO4-H2O values. By combining all data from both cultures, an average ε18OSO4-H2O value of 5.6 ± 0.3‰ was obtained for SMAP. This value falls between those previously reported for bacterial oxidation of sphalerite and elemental sulfur (7-9‰) and abiotic and biotic oxidation of pyrite and chalcopyrite (2-4‰). Sulfur isotope fractionation between sulfide and sulfate formed by A.vinosum was negligible (0.1 ± 0.2‰) during all experiments. For C. tepidum an apparent fractionation of -2.3 ± 0.5‰ was observed during the earlier stages of oxidation based on bulk δ34S measurements of sulfate and sulfide and became smaller (-0.7

  11. The partitioning of hydrogen sulfide in the condensers of Geysers Unit 15

    Science.gov (United States)

    Weres, O.

    1982-09-01

    Geysers Unit 15 was the first of the geothermal units equipped with surface condensers to go on line at The Geysers power plant of the Pacific Gas and Electric Company. Units 1 through 12 have contact condensers. The switch to surface condensers was motivated by considerations of hydrogen sulfide mission abatement. In the contact condensers, there is a large liquid-to-vapor ratio, and about 75% of the hydrogen sulfide that is present in the geothermal steam supply ends up dissolved in the cooling water. Once in the cooling water, it is emitted to the atmosphere from the cooling towers unless further, tertiary abatement is employed. It was reasoned that, because the liquid-to-vapor ratio in a surface condenser would be smaller by a factor of about twenty-five than in a contact condenser, most of the hydrogen sulfide would remain in the vapor phase and leave with the gas vented from the condenser rather than by dissolving in the condensate. Unit 15 is equipped with a Stretford Unit, which removes the hydrogen sulfide from the vent gas and converts it to elemental sulfur by reaction with air. Therefore, the fraction of the hydrogen sulfide that leaves the condenser with the vent gas is not emitted to the atmosphere.

  12. THE SULFIDATION/OXIDATION RESISTANCE OF TWO Ni-Cr-Al-Y ALLOYS AT 700℃

    Institute of Scientific and Technical Information of China (English)

    Y.X.Lu; W.X.Chen; R.Eadie

    2004-01-01

    The high temperature corrosion resistance of Ni-25.gCr-13.5Al-1.2Y-0.6Si and Ni-10.2Co-12.4 Cr-16.0A l-0.5 Y-0.2Hf alloys was assessed in sulfidation/oxidation environments.In the environment with a sulfur partial pressure of 1Pa.and an oxygen partial pressure of 10-19Pa,both these alloys exhibited three distinct stages in the weight gain-time curve when tested at 700℃.In the initial stage,selective sulfidation of Cr suppressed the formation of the other metal sulfides,resulting in lower weight gains.In the transient stage,breakdown and cracking of Cr sulfides and insufficient concentration of Cr at the outer zone led to the rapid formation of Ni sulfides and a rapid increase in weight.In the steady-state stage,corrosion was controlled by the diffusion of anions and/or cations,which led to a parabolic rate law.

  13. Thermodynamic Model and Database for Sulfides Dissolved in Molten Oxide Slags

    Science.gov (United States)

    Kang, Youn-Bae; Pelton, Arthur D.

    2009-12-01

    A thermodynamic model has been developed in the framework of the modified quasichemical model in the quadruplet approximation to permit the calculation of solubilities of various gaseous species (sulfide, sulfate, nitride, carbide, water, etc.) in molten slags. The model calculates the solubilities solely from knowledge of the thermodynamic activities of the component oxides and the Gibbs energies of the pure liquid components (oxides, sulfides, sulfates, etc.). In the current article, it is shown that solubilities of sulfur as sulfide in Al2O3-CaO-FeO-Fe2O3-MgO-MnO-SiO2-TiO2-Ti2O3 multicomponent slags, which are predicted from the current model with no adjustable model parameters, are in good agreement with all available experimental data. The article also provides a thorough review of experimental sulfide capacity data for this system. The model applies at all compositions from pure oxides to pure sulfides and from basic to acidic slags. By coupling this database with other evaluated databases, such as those for molten metal and gaseous phases, and with general software for Gibbs energy minimization, practically important slag/metal/gas/solid equilibria can be computed such as S-distribution ratios.

  14. Selective Sulfidation of Lead Smelter Slag with Pyrite and Flotation Behavior of Synthetic ZnS

    Science.gov (United States)

    Han, Junwei; Liu, Wei; Wang, Dawei; Jiao, Fen; Zhang, Tianfu; Qin, Wenqing

    2016-08-01

    The selective sulfidation of lead smelter slag with pyrite in the presence of carbon and Na salts, and the flotation behavior of synthetic ZnS were studied. The effects of temperature, time, pyrite dosage, Na salts, and carbon additions were investigated based on thermodynamic calculation, and correspondingly, the growth mechanism of ZnS particles was studied at high temperatures. The results indicated that the zinc in lead smelter slag was selectively converted into zinc sulfides by sulfidation roasting. The sulfidation degree of zinc was increased until the temperature, time, pyrite, and carbon dosages reached their optimum values, under which it was more than 95 pct. The growth of ZnS particles largely depended upon roasting temperature, and the ZnS grains were significantly increased above 1373 K (1100 °C) due to the formation of a liquid phase. After the roasting, the zinc sulfides generated had a good floatability, and 88.34 pct of zinc was recovered by conventional flotation.

  15. Characteristics of the interaction of azulene with water and hydrogen sulfide: A computational study.

    Science.gov (United States)

    Cabaleiro-Lago, Enrique M; Rodríguez-Otero, Jesús; Peña-Gallego, Angeles

    2008-08-28

    A computational study was carried out for studying the characteristics of the interaction between azulene and water or hydrogen sulfide. In azulene...water complex the water molecule is located with both hydrogen atoms pointing toward the aromatic cloud but displaced to the five-membered ring. Hydrogen sulfide adopts a similar arrangement but located roughly over the central C-C bond of azulene. Calculations show that hydrogen sulfide interacts with azulene more strongly (-4.19 kcal/mol) than water (-3.76 kcal/mol), although this is only revealed at the highest levels of calculation. The nature of the interaction is electrostatic and dispersive in the same percentage for water cluster, whereas for hydrogen sulfide dispersion is the dominant contribution. Clusters containing two water molecules are controlled by the possibility of establishing an O-H...O hydrogen bond. As a consequence, the most stable structure corresponds to the interaction between a water dimer and azulene, with an interaction energy amounting to -11.77 kcal/mol. Hydrogen sulfide interaction is stronger with azulene than with itself, so structures with S-H...S contact and others, where H(2)S only interacts with azulene, present similar interaction energies (-8.02 kcal/mol for the most stable one).

  16. Automatic mechanism generation for pyrolysis of di-tert-butyl sulfide.

    Science.gov (United States)

    Class, Caleb A; Liu, Mengjie; Vandeputte, Aäron G; Green, William H

    2016-08-01

    The automated Reaction Mechanism Generator (RMG), using rate parameters derived from ab initio CCSD(T) calculations, is used to build reaction networks for the thermal decomposition of di-tert-butyl sulfide. Simulation results were compared with data from pyrolysis experiments with and without the addition of a cyclohexene inhibitor. Purely free-radical chemistry did not properly explain the reactivity of di-tert-butyl sulfide, as the previous experimental work showed that the sulfide decomposed via first-order kinetics in the presence and absence of the radical inhibitor. The concerted unimolecular decomposition of di-tert-butyl sulfide to form isobutene and tert-butyl thiol was found to be a key reaction in both cases, as it explained the first-order sulfide decomposition. The computer-generated kinetic model predictions quantitatively match most of the experimental data, but the model is apparently missing pathways for radical-induced decomposition of thiols to form elemental sulfur. Cyclohexene has a significant effect on the composition of the radical pool, and this led to dramatic changes in the resulting product distribution. PMID:27431650

  17. Highly selective fluorescence turn-on sensor for hydrogen sulfide and imaging in living cells

    International Nuclear Information System (INIS)

    A displacement method of detecting hydrogen sulfide in aqueous media based on complex L–Cu ensemble is developed. Once combined with Cu2+, complex L–Cu displayed high specificity for sulfide anion. Among the various anions, only sulfide anion induce the revival of fluoresecence of compound L, which is quenched by Cu2+, resulting in turn-on type sensing sulfide anion. Complex L–Cu exhibits a highly sensitive fluorescent response toward S2− by releasing compound L to give a remarkable change with 20-fold fluorescence intensity enhancement under 2 equivalent of S2− added in Tris–HCl/ DMF (20 mM, 6/4, v/v), and also exhibits a dynamic response range for S2− from 5×10−7 to 5×10−6 M, with a detection limit of 0.18 μM. In addition, the turn-on fluorescent change upon the addition of S2− is also applied in cell imaging. -- Highlights: ► We have developed a displacement method with sensing hydrogen sulfide based on a complex L–Cu. ► It exhibits high selectivity, high sensitivity with a 20-fold fluorescence enhancement. ► It exhibited a low detection limit of 0.18 μM. ► It is applied in vitro imaging of S2− in the living cells

  18. Spectroscopic study of Se(IV) removal from water by reductive precipitation using sulfide.

    Science.gov (United States)

    Jung, Bahngmi; Safan, Aya; Batchelor, Bill; Abdel-Wahab, Ahmed

    2016-11-01

    This study investigates the removal of selenium (IV) from water by reductive precipitation using sodium sulfide at neutral pH. Also, it examines the application of UV light as an activating method to enhance reductive precipitation. Furthermore, this work evaluates the effects of sulfide dose and solution pH on behavior of Se(IV) reduction. Selenium was effectively removed in sulfide solution at both neutral and acidic pH. UV irradiation did not enhance removal efficiency of Se(IV) at conditions tested, but it affected solids morphology and composition. SEM/EDS and XPS results showed that selenite was reduced to elemental Se or Se-S precipitates (e.g. SenS8-n) in sulfide solution. High resolution S 2p XPS spectra suggested the presence of sulfur-containing anions (e.g. S2O3(2-), HSO3(-), etc.) or elemental S (S(0)), monosulfide (S(2-)), and polysulfides (Sn(2-)), which could be produced from sulfide photolysis or reaction with Se. In addition, large aggregates of irregular shape, which suggest Se-S precipitates or elemental sulfur, were found more prominently at pH 4 than at pH 7, and they were more noticeable in the presence of UV with longer reaction times. In addition, XRD patterns showed that gray elemental Se solids were dominant in experiments without UV, whereas Se-S precipitates (Se3S5) with an orange color were found in those with UV. PMID:27552695

  19. Bioconversion of high concentrations of hydrogen sulfide to elemental sulfur in airlift bioreactor.

    Science.gov (United States)

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

    2014-01-01

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

  20. Pathways of sulfide oxidation by haloalkaliphilic bacteria in limited-oxygen gas lift bioreactors.

    Science.gov (United States)

    Klok, Johannes B M; van den Bosch, Pim L F; Buisman, Cees J N; Stams, Alfons J M; Keesman, Karel J; Janssen, Albert J H

    2012-07-17

    Physicochemical processes, such as the Lo-cat and Amine-Claus process, are commonly used to remove hydrogen sulfide from hydrocarbon gas streams such as landfill gas, natural gas, and synthesis gas. Biodesulfurization offers environmental advantages, but still requires optimization and more insight in the reaction pathways and kinetics. We carried out experiments with gas lift bioreactors inoculated with haloalkaliphilic sulfide-oxidizing bacteria. At oxygen-limiting levels, that is, below an O(2)/H(2)S mole ratio of 1, sulfide was oxidized to elemental sulfur and sulfate. We propose that the bacteria reduce NAD(+) without direct transfer of electrons to oxygen and that this is most likely the main route for oxidizing sulfide to elemental sulfur which is subsequently oxidized to sulfate in oxygen-limited bioreactors. We call this pathway the limited oxygen route (LOR). Biomass growth under these conditions is significantly lower than at higher oxygen levels. These findings emphasize the importance of accurate process control. This work also identifies a need for studies exploring similar pathways in other sulfide oxidizers such as Thiobacillus bacteria.

  1. Formation of Fe-sulfides in cultures of sulfate-reducing bacteria

    International Nuclear Information System (INIS)

    The purpose of this study was to synthesize Fe-sulfides produced with sulfate-reducing bacteria under experimental laboratory conditions. Fe-sulfides were precipitated with biologically produced sulfide in cultures growing at 22, 45, and 60 deg. C for up to 16 weeks. Abiotic controls were prepared by reacting liquid media with Na2S solutions. Precipitates were collected anaerobically, freeze-dried and analyzed by X-ray diffraction. Additional analyses included total Fe and S content, magnetic susceptibility, specific surface area, and scanning electron microscopy. Mackinawite (FeS) and greigite (Fe3S4) were the dominant iron sulfide phases formed in sulfate-reducing bacterial cultures. An increase in the incubation temperature from 22 to 60 deg. C enhanced the crystallinity of the Fe-sulfides. Generally, greigite was more prevalent in abiotic samples and mackinawite in biogenic materials. Pyrite (FeS2) was also found in abiotic precipitates. Abiotic samples had a higher magnetic susceptibility because of the greigite and displayed improved crystallinity compared to biotic materials.

  2. Acidic Microenvironments in Waste Rock Characterized by Neutral Drainage: Bacteria–Mineral Interactions at Sulfide Surfaces

    Directory of Open Access Journals (Sweden)

    John W. Dockrey

    2014-03-01

    Full Text Available Microbial populations and microbe-mineral interactions were examined in waste rock characterized by neutral rock drainage (NRD. Samples of three primary sulfide-bearing waste rock types (i.e., marble-hornfels, intrusive, exoskarn were collected from field-scale experiments at the Antamina Cu–Zn–Mo mine, Peru. Microbial communities within all samples were dominated by neutrophilic thiosulfate oxidizing bacteria. However, acidophilic iron and sulfur oxidizers were present within intrusive waste rock characterized by bulk circumneutral pH drainage. The extensive development of microbially colonized porous Fe(III (oxyhydroxide and Fe(III (oxyhydroxysulfate precipitates was observed at sulfide-mineral surfaces during examination by field emission-scanning electron microscopy-energy dispersive X-ray spectroscopy (FE-SEM-EDS. Linear combination fitting of bulk extended X-ray absorption fine structure (EXAFS spectra for these precipitates indicated they were composed of schwertmannite [Fe8O8(OH6–4.5(SO41–1.75], lepidocrocite [γ-FeO(OH] and K-jarosite [KFe3(OH6(SO42]. The presence of schwertmannite and K-jarosite is indicative of the development of localized acidic microenvironments at sulfide-mineral surfaces. Extensive bacterial colonization of this porous layer and pitting of underlying sulfide-mineral surfaces suggests that acidic microenvironments can play an important role in sulfide-mineral oxidation under bulk circumneutral pH conditions. These findings have important implications for water quality management in NRD settings.

  3. Modeling the Effect of Dissolved Hydrogen Sulfide on Mg2+-water Complex on Dolomite {104} Surfaces

    CERN Document Server

    Shen, Zhizhang; Brown, Philip E; Szlufarska, Izabela; Xu, Huifang

    2016-01-01

    The key kinetic barrier to dolomite formation is related to the surface Mg2+-H2O complex, which hinders binding of surface Mg2+ ions to the CO3 2- ions in solution. It has been proposed that this reaction can be catalyzed by dissolved hydrogen sulfide. To characterize the role of dissolved hydrogen sulfide in the dehydration of surface Mg 2+ ions, ab initio simulations based on density functional theory (DFT) were carried out to study the thermodynamics of competitive adsorption of hydrogen sulfide and water on dolomite (104) surfaces from solution. We find that water is thermodynamically more stable on the surface with the difference in adsorption energy of -13.6 kJ/mol (in vacuum) and -12.8 kJ/mol (in aqueous solution). However, aqueous hydrogen sulfide adsorbed on the surface increases the Mg2+-H2O distances on surrounding surface sites. Two possible mechanisms were proposed for the catalytic effects of adsorbed hydrogen sulfide on the anhydrous Ca-Mg-carbonate crystallization at low temperature.

  4. Formation of Fe-sulfides in cultures of sulfate-reducing bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Gramp, Jonathan P. [Department of Microbiology, Ohio State University, 484 W. 12th Avenue, Columbus, OH 43210 (United States); Bigham, Jerry M.; Jones, F. Sandy [School of Environment and Natural Resources, 2021 Coffey Road, Ohio State University, Columbus, OH 43210 (United States); Tuovinen, Olli H., E-mail: tuovinen.1@osu.edu [Department of Microbiology, Ohio State University, 484 W. 12th Avenue, Columbus, OH 43210 (United States) and Department of Chemistry and Bioengineering, Tampere University of Technology, P.O. Box 541, FI 33101 Tampere (Finland)

    2010-03-15

    The purpose of this study was to synthesize Fe-sulfides produced with sulfate-reducing bacteria under experimental laboratory conditions. Fe-sulfides were precipitated with biologically produced sulfide in cultures growing at 22, 45, and 60 deg. C for up to 16 weeks. Abiotic controls were prepared by reacting liquid media with Na{sub 2}S solutions. Precipitates were collected anaerobically, freeze-dried and analyzed by X-ray diffraction. Additional analyses included total Fe and S content, magnetic susceptibility, specific surface area, and scanning electron microscopy. Mackinawite (FeS) and greigite (Fe{sub 3}S{sub 4}) were the dominant iron sulfide phases formed in sulfate-reducing bacterial cultures. An increase in the incubation temperature from 22 to 60 deg. C enhanced the crystallinity of the Fe-sulfides. Generally, greigite was more prevalent in abiotic samples and mackinawite in biogenic materials. Pyrite (FeS{sub 2}) was also found in abiotic precipitates. Abiotic samples had a higher magnetic susceptibility because of the greigite and displayed improved crystallinity compared to biotic materials.

  5. Formation of Fe-sulfides in cultures of sulfate-reducing bacteria.

    Science.gov (United States)

    Gramp, Jonathan P; Bigham, Jerry M; Jones, F Sandy; Tuovinen, Olli H

    2010-03-15

    The purpose of this study was to synthesize Fe-sulfides produced with sulfate-reducing bacteria under experimental laboratory conditions. Fe-sulfides were precipitated with biologically produced sulfide in cultures growing at 22, 45, and 60 degrees C for up to 16 weeks. Abiotic controls were prepared by reacting liquid media with Na(2)S solutions. Precipitates were collected anaerobically, freeze-dried and analyzed by X-ray diffraction. Additional analyses included total Fe and S content, magnetic susceptibility, specific surface area, and scanning electron microscopy. Mackinawite (FeS) and greigite (Fe(3)S(4)) were the dominant iron sulfide phases formed in sulfate-reducing bacterial cultures. An increase in the incubation temperature from 22 to 60 degrees C enhanced the crystallinity of the Fe-sulfides. Generally, greigite was more prevalent in abiotic samples and mackinawite in biogenic materials. Pyrite (FeS(2)) was also found in abiotic precipitates. Abiotic samples had a higher magnetic susceptibility because of the greigite and displayed improved crystallinity compared to biotic materials. PMID:19962824

  6. Partition coefficients for Ni, Cu, Pd, Pt, Rh, and Ir between monosulfide solid solution and sulfide liquid and the formation of compositionally zoned Ni-Cu sulfide bodies by fractional crystallization of sulfide liquid

    DEFF Research Database (Denmark)

    Barnes, S.J.; Makovicky, E.; Makovicky, M.;

    1996-01-01

    Many nickel–copper sulfide orebodies contain Cu- and Fe-rich portions. The Fe-rich ore is generally richer in Os, Ir, Ru, and Rh and poorer in Pt, Pd, and Au than the Cu-rich ore. In komatiite-hosted ores Ni tends to be concentrated in the Cu-rich ore, whereas in tholeiitic ores it tends to be co...

  7. Synthesis, Deposition, and Microstructure Development of Thin Films Formed by Sulfidation and Selenization of Copper Zinc Tin Sulfide Nanocrystals

    Science.gov (United States)

    Chernomordik, Boris David

    Significant reduction in greenhouse gas emission and pollution associated with the global power demand can be accomplished by supplying tens-of-terawatts of power with solar cell technologies. No one solar cell material currently on the market is poised to meet this challenge due to issues such as manufacturing cost, material shortage, or material toxicity. For this reason, there is increasing interest in efficient light-absorbing materials that are comprised of abundant and non-toxic elements for thin film solar cell. Among these materials are copper zinc tin sulfide (Cu2ZnSnS4, or CZTS), copper zinc tin selenide (Cu2ZnSnSe4, or CZTSe), and copper zinc tin sulfoselenide alloys [Cu2ZnSn(SxSe1-x )4, or CZTSSe]. Laboratory power conversion efficiencies of CZTSSe-based solar cells have risen to almost 13% in less than three decades of research. Meeting the terawatt challenge will also require low cost fabrication. CZTSSe thin films from annealed colloidal nanocrystal coatings is an example of solution-based methods that can reduce manufacturing costs through advantages such as high throughput, high material utilization, and low capital expenses. The film microstructure and grain size affects the solar cell performance. To realize low cost commercial production and high efficiencies of CZTSSe-based solar cells, it is necessary to understand the fundamental factors that affect crystal growth and microstructure evolution during CZTSSe annealing. Cu2ZnSnS4 (CZTS) nanocrystals were synthesized via thermolysis of single-source cation and sulfur precursors copper, zinc and tin diethyldithiocarbamates. The average nanocrystal size could be tuned between 2 nm and 40 nm, by varying the synthesis temperature between 150 °C and 340 °C. The synthesis is rapid and is completed in less than 10 minutes. Characterization by X-ray diffraction, Raman spectroscopy, transmission electron microscopy and energy dispersive X-ray spectroscopy confirm that the nanocrystals are nominally

  8. Formation of Zn- and Fe-sulfides near hydrothermal vents at the Eastern Lau Spreading Center: implications for sulfide bioavailability to chemoautotrophs

    Directory of Open Access Journals (Sweden)

    Yucel Mustafa

    2008-05-01

    Full Text Available Abstract Background The speciation of dissolved sulfide in the water immediately surrounding deep-ocean hydrothermal vents is critical to chemoautotrophic organisms that are the primary producers of these ecosystems. The objective of this research was to identify the role of Zn and Fe for controlling the speciation of sulfide in the hydrothermal vent fields at the Eastern Lau Spreading Center (ELSC in the southern Pacific Ocean. Compared to other well-studied hydrothermal systems in the Pacific, the ELSC is notable for unique ridge characteristics and gradients over short distances along the north-south ridge axis. Results In June 2005, diffuse-flow ( 250°C vent fluids were collected from four field sites along the ELSC ridge axis. Total and filtered Zn and Fe concentrations were quantified in the vent fluid samples using voltammetric and spectrometric analyses. The results indicated north-to-south variability in vent fluid composition. In the high temperature vent fluids, the ratio of total Fe to total Zn varied from 39 at Kilo Moana, the most northern site, to less than 7 at the other three sites. The concentrations of total Zn, Fe, and acid-volatile sulfide indicated that oversaturation and precipitation of sphalerite (ZnS(s and pyrite (FeS2(s were possible during cooling of the vent fluids as they mixed with the surrounding seawater. In contrast, most samples were undersaturated with respect to mackinawite (FeS(s. The reactivity of Zn(II in the filtered samples was tested by adding Cu(II to the samples to induce metal-exchange reactions. In a portion of the samples, the concentration of labile Zn2+ increased after the addition of Cu(II, indicating the presence of strongly-bound Zn(II species such as ZnS clusters and nanoparticles. Conclusion Results of this study suggest that Zn is important to sulfide speciation at ELSC vent habitats, particularly at the southern sites where Zn concentrations increase relative to Fe. As the hydrothermal

  9. Growth and chemosensory behavior of sulfate-reducing bacteria in oxygen-sulfide gradients

    DEFF Research Database (Denmark)

    Sass, Andrea M.; Wieland, Andrea Eschemann; Kühl, Michael;

    2002-01-01

    Growth and chemotactic behavior in oxic–anoxic gradients were studied with two freshwater and four marine strains of sulfate-reducing bacteria related to the genera Desulfovibrio, Desulfomicrobium or Desulfobulbus. Cells were grown in oxygen–sulfide counter-gradients within tubes filled with agar...... chemotactically to lactate, nitrate, sulfate and thiosulfate, and even sulfide functioned as an attractant. In oxic–anoxic gradients the bacteria moved away from high oxygen concentrations and formed bands at the outer edge of the oxic zone at low oxygen concentration (... to actively change the extension and slope of the gradients by oxygen reduction with lactate or even sulfide as electron donor. Generally, the chemotactic behavior was in agreement with a defense strategy that re-establishes anoxic conditions, thus promoting anaerobic growth and, in a natural community...

  10. The Effect of Oxygen Potential on the Sulfide Capacity for Slags Containing Multivalent Species

    Science.gov (United States)

    Allertz, Carl; Selleby, Malin; Sichen, Du

    2016-10-01

    The dependence of sulfide capacity on the oxygen partial pressure for slags containing multivalent species was investigated experimentally using a slag containing vanadium oxide. Copper-slag equilibration experiments were carried out at 1873 K (1600 °C) in the approximate oxygen partial pressure range 10-15.4 to 10-9 atm. The sulfide capacity was found to be strongly dependent on the oxygen potential in this slag system, increasing with the oxygen partial pressure. The sulfide capacity changed by more than two orders of magnitude over the oxygen partial pressure range. The effect of changing oxygen partial pressure was found to be much greater than the effect of changing slag composition at a fixed oxygen partial pressure.

  11. Coupling of Alcohols over Alkali-Promoted Cobalt-Molybdenum Sulfide

    DEFF Research Database (Denmark)

    Christensen, Jakob Munkholt; Jensen, Peter Arendt; Schiødt, N.C.;

    2010-01-01

    Double or nothing: Higher alcohols are produced by the hydrogenation of CO with a K-promoted Co-MoS2/C catalyst. Ethanol, which is passed over the sulfide catalyst along with CO and H2, is mainly converted into 1-butanol, which indicates that alcohol condensation contributes to the build-up of hi......Double or nothing: Higher alcohols are produced by the hydrogenation of CO with a K-promoted Co-MoS2/C catalyst. Ethanol, which is passed over the sulfide catalyst along with CO and H2, is mainly converted into 1-butanol, which indicates that alcohol condensation contributes to the build......-up of higher alcohols over the sulfide catalyst. In a nitrogen atmosphere, ethanol is also in part converted into 1-butanol, although ethyl acetate is the major product....

  12. Sodium sulfide leaching of low-grade jamesonite concentrate in production of sodium pyroantimoniate

    Institute of Scientific and Technical Information of China (English)

    YANG Tian-zu; JIANG Ming-xi; LAI Qiong-lin; CHEN Jin-zhong

    2005-01-01

    Sodium sulfide leaching of a low-grade jamesonite concentrate in the production of sodium pyroantimoniate through the air oxidation process and the influencing factors on the leaching rate of antimony were investigated.In order to decrease the consumption of sodium sulfide and increase the concentration of antimony in the leaching solution, two-stage leaching of jamesonite concentrate and combination leaching of high-grade stibnite concentrate and jamesonite concentrate were used. The experimental results showthat the consumptions of sodium sulfide for the two-stage leaching process and the combination leaching process are decreased by 20% and 60% compared to those of one-stage leaching process respectively. The final concentrations of antimony in the leaching solutions of both processes are above 100 g/L.

  13. Characterization of AISI 1005 corrosion films grown under cyclic voltammetry of low sulfide ion concentrations

    International Nuclear Information System (INIS)

    Highlights: •The corrosion of AISI 1005 in sulfide solutions was investigated. •The mechanism of film growth on carbon steel in sulfide solutions was studied. •Film growth was characterized using SEM, EDX, XRD and Mössbauer spectroscopy. •Growth of AISI 1005 corrosion films under cyclic voltammetry. -- Abstract: The mechanism of AISI 1005 corrosion in sulfide ion solutions has been investigated using cyclic voltammetry, electrochemical impedance spectroscopy, X-ray diffraction (XRD) and Mössbauer spectroscopy (MS). The proposed mechanism occurs with the initial formation of oxygenated ferrous species followed by adsorption of HS− species, precipitation of iron monosulfides and their partial conversion to bisulfide iron. This mechanism was demonstrated by XRD results that revealed Fe-O and Fe-S phases and by MS results that detected pyrite as the major proportion (94%) of the iron species in the corrosion product

  14. The Effect of Oxygen Potential on the Sulfide Capacity for Slags Containing Multivalent Species

    Science.gov (United States)

    Allertz, Carl; Selleby, Malin; Sichen, Du

    2016-06-01

    The dependence of sulfide capacity on the oxygen partial pressure for slags containing multivalent species was investigated experimentally using a slag containing vanadium oxide. Copper-slag equilibration experiments were carried out at 1873 K (1600 °C) in the approximate oxygen partial pressure range 10-15.4 to 10-9 atm. The sulfide capacity was found to be strongly dependent on the oxygen potential in this slag system, increasing with the oxygen partial pressure. The sulfide capacity changed by more than two orders of magnitude over the oxygen partial pressure range. The effect of changing oxygen partial pressure was found to be much greater than the effect of changing slag composition at a fixed oxygen partial pressure.

  15. Nanocomposites Based on Metal and Metal Sulfide Clusters Embedded in Polystyrene

    Directory of Open Access Journals (Sweden)

    Gianfranco Carotenuto

    2011-08-01

    Full Text Available Transition-metal alkane-thiolates (i.e., organic salts with formula Me(SRx, where R is a linear aliphatic hydrocarbon group, –CnH2n+1 undergo a thermolysis reaction at moderately low temperatures (close to 200 °C, which produces metal atoms or metal sulfide species and an organic by-product, disulfide (RSSR or thioether (RSR molecules, respectively. Alkane-thiolates are non-polar chemical compounds that dissolve in most techno-polymers and the resulting solid solutions can be annealed to generate polymer-embedded metal or metal sulfide clusters. Here, the preparation of silver and gold clusters embedded into amorphous polystyrene by thermolysis of a dodecyl-thiolate precursor is described in detail. However, this chemical approach is quite universal and a large variety of polymer-embedded metals or metal sulfides could be similarly prepared.

  16. Determination of kinetics and stoichiometry of chemical sulfide oxidation in wastewater of sewer networks

    DEFF Research Database (Denmark)

    Nielsen, A.H.; Vollertsen, Jes; Hvitved-jacobsen, Thorkild

    2003-01-01

    A method for determination of kinetics and stoichiometry of chemical sulfide oxidation by dissolved oxygen (DO) in wastewater is presented. The method was particularly developed to investigate chemical sulfide oxidation in wastewater of sewer networks at low DO concentrations. The method is based...... parameters determined in a triplicate experiment. The kinetic parameters determined in 25 experiments on wastewater samples from a single site exhibited good constancy with a variation of the same order of magnitude as the precision of the method. It was found that the stoichiometry of the reaction could...... be considered constant during the course of the experiments although intermediates accumulated. This was explained by an apparent slow oxidation rate of the intermediates. The method was capable of determining kinetics and stoichiometry of chemical sulfide oxidation at DO concentrations lower than 1 g of O2 m...

  17. Incorporation of sulfide ions into the cadmium(II) thiolate cluster of Cicer arietinum metallothionein2.

    Science.gov (United States)

    Wan, Xiaoqiong; Freisinger, Eva

    2013-01-18

    The plant metallothionein2 from Cicer arietinum (chickpea), cic-MT2, is known to coordinate five divalent metal ions such as Zn(II) or Cd(II), which are arranged in a single metal thiolate cluster. When the Zn(II) form of the protein is titrated with Cd(II) ions in the presence of sulfide ions, an increased Cd(II) binding capacity and concomitant incorporation of sulfide ions into the cluster are observed. The exact stoichiometry of this novel cluster, its spectroscopic properties, and the significantly increased pH stability are analyzed with different techniques, including UV and circular dichroism spectroscopy and colorimetric assays. Limited proteolytic digestion provides information about the spacial arrangement of the cluster within the protein. Increasing the Cd(II) scavenging properties of a metallothionein by additionally recruiting sulfide ions might be an economic and very efficient detoxification strategy for plants.

  18. Denitrifying sulfide removal process on high-salinity wastewaters in the presence of Halomonas sp.

    Science.gov (United States)

    Liu, Chunshuang; Zhao, Dongfeng; Ma, Wenjuan; Guo, Yadong; Wang, Aijie; Wang, Qilin; Lee, Duu-Jong

    2016-02-01

    Biological conversion of sulfide, acetate, and nitrate to, respectively, elemental sulfur (S(0)), carbon dioxide, and nitrogen-containing gas (such as N2) at NaCl concentration of 35-70 g/L was achieved in an expanded granular sludge bed (EGSB) reactor. A C/N ratio of 1:1 was noted to achieve high sulfide removal and S(0) conversion rate at high salinity. The extracellular polymeric substance (EPS) quantities were increased with NaCl concentration, being 11.4-mg/g volatile-suspended solids at 70 mg/L NaCl. The denitrifying sulfide removal (DSR) consortium incorporated Thauera sp. and Halomonas sp. as the heterotrophs and Azoarcus sp. being the autotrophs at high salinity condition. Halomonas sp. correlates with the enhanced DSR performance at high salinity. PMID:26454867

  19. Self-assembly of Copper Sulfide Nanoparticles to Solid, Hollow Spherical and Wire-Shaped Structures

    Institute of Scientific and Technical Information of China (English)

    NAN Zhao-Dong; WEI Cheng-Zhen; WANG Xue-Ying; HAO Hai-Yan

    2008-01-01

    Copper sulfides, such as Cu7S4, Cu1.8S, Cu1.81S and Cu2S, in the wire-like, and solid and hollow ball-like shapes congregated from nano-spherical particles and nanoslices, have been prepared by a solvothermal method using a mixture of water and ethylene glycol as solvent. CuSO4 and thiourea were used as the starting materials without as- sistance of any surfactant or template. The results show that the water content in the solvent affects the morphology of the samples, and the reaction time and temperature affect the crystal structure and morphology. On the basis of the obtained results, the formation processes of different morphologies of copper sulfides can be interpreted by the following mechanism: nanoparticles of copper sulfides initially formed, then the wire-like structures were gradually created, and finally translated to solid and hollow spherical structures under the different experimental conditions.

  20. Direct chlorination process for geothermal power plant off-gas - hydrogen sulfide abatement

    Energy Technology Data Exchange (ETDEWEB)

    Sims, A.V.

    1983-06-01

    The Direct Chlorination Process removes hydrogen sulfide from geothermal off-gases by reacting hydrogen sulfide with chlorine in the gas phase. Hydrogen chloride and elemental sulfur are formed by this reaction. The Direct Chlorination Process has been successfully demonstrated by an on-site operation of a pilot plant at the 3 M We HPG-A geothermal power plant in the Puna District on the island of Hawaii. Over 99.5 percent hydrogen sulfide removal was achieved in a single reaction state. Chlorine gas did not escape the pilot plant, even when 90 percent excess chlorine gas was used. A preliminary economic evaluation of the Direct Chlorination Process indicates that it is very competitive with the Stretford Process. Compared to the Stretford Process, the Direct Chlorination Process requires about one-third the initial capital investment and about one-fourth the net daily expenditure.