Charge transfer cross sections for dysprosium and cerium

Energy Technology Data Exchange (ETDEWEB)

Adachi, Hajime; Tamura, Koji; Okazaki, Tetsuji; Shibata, Takemasa [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

1998-06-01

Symmetric resonant charge transfer cross sections between singly ionized ions and the parent atoms were measured for dysprosium and cerium in the impact energy of 200-2000eV. The cross sections were determined from the ratio between the number of ions produced by charge transfer and those in primary ion beam. The primary ion beam was produced by a laser ion source in which their atoms were ionized by laser resonant photo-ionization. The slow ions produced by charge transfer and fast primary ions were detected with Faraday cups. The obtained cross sections were (1.82{+-}0.14) x 10{sup -14} cm{sup 2} for dysprosium and (0.88{+-}0.12) x 10{sup -14} cm{sup 2} for cerium in the above energy range. The difference of these values can mostly be explained by considering the electron configurations of these atoms and ions. (author)

Charge transfer cross sections for dysprosium and cerium

International Nuclear Information System (INIS)

Adachi, Hajime; Tamura, Koji; Okazaki, Tetsuji; Shibata, Takemasa

1998-06-01

Symmetric resonant charge transfer cross sections between singly ionized ions and the parent atoms were measured for dysprosium and cerium in the impact energy of 200-2000eV. The cross sections were determined from the ratio between the number of ions produced by charge transfer and those in primary ion beam. The primary ion beam was produced by a laser ion source in which their atoms were ionized by laser resonant photo-ionization. The slow ions produced by charge transfer and fast primary ions were detected with Faraday cups. The obtained cross sections were (1.82±0.14) x 10 -14 cm 2 for dysprosium and (0.88±0.12) x 10 -14 cm 2 for cerium in the above energy range. The difference of these values can mostly be explained by considering the electron configurations of these atoms and ions. (author)

Synthesis, structural characterization and in vitro testing of dysprosium containing silica particles as potential MRI contrast enhancing agents

International Nuclear Information System (INIS)

Chiriac, L.B.; Trandafir, D.L.; Turcu, R.V.F.; Todea, M.; Simon, S.

2016-01-01

Highlights: • Dysprosium containing silica microparticles obtained by freeze and spray drying. • Higher structural units interconnection achieved in freeze vs. spray dried samples. • Dy occurance on the outermost layer of the microparticles evidenced by XPS. • Enhanced MRI contrast observed for freeze dried samples with 5% mol Dy_2O_3. - Abstract: The work is focused on synthesis and structural characterization of novel dysprosium-doped silica particles which could be considered as MRI contrast agents. Sol-gel derived silica rich particles obtained via freeze-drying and spray-drying processing methods were structurally characterized by XRD, "2"9Si MAS-NMR and XPS methods. The occurrence of dysprosium on the outermost layer of dysprosium containing silica particles was investigated by XPS analysis. The MRI contrast agent characteristics have been tested using RARE-T_1 and RARE-T_2 protocols. The contrast of MRI images delivered by the investigated samples was correlated with their local structure. Dysprosium disposal on microparticles with surface structure characterised by decreased connectivity of the silicate network units favours dark T_2-weighted MRI contrast properties.

Dysprosium-containing layered double hydroxides nanoparticles intercalated with biologically active species as an approach for theranostic systems

Energy Technology Data Exchange (ETDEWEB)

Arratia-Quijada, Jenny [Departamento de Ciencias de la Salud, Centro Universitario Tonalá, Universidad de Guadalajara, Av. Nuevo Periférico No. 555, C.P. 48525, Tonalá, Jalisco (Mexico); Sánchez Jiménez, Cecilia [Departamento de Química, Universidad de Guadalajara, Boulevard Marcelino García Barragán 1421, C.P. 44430, Guadalajara, Jalisco (Mexico); Gurinov, Andrey [Research Resources Center for Magnetic Resonance, St. Petersburg State University, Universitetskiy pr. 26, 198504 St. Petersburg (Russian Federation); NMR Core Lab, King Abdullah University of Science and Technology, Thuwal 23955-6900 (Saudi Arabia); Pérez Centeno, Armando; Ceja Andrade, Israel [Departamento de Física, Universidad de Guadalajara, Boulevard Marcelino García Barragán 1421, C.P. 44430, Guadalajara, Jalisco (Mexico); Carbajal Arízaga, Gregorio Guadalupe, E-mail: gregoriocarbajal@yahoo.com.mx [Departamento de Química, Universidad de Guadalajara, Boulevard Marcelino García Barragán 1421, C.P. 44430, Guadalajara, Jalisco (Mexico)

2016-01-15

Graphical abstract: - Highlights: • LDH structure including dysprosium was prepared by co-precipitation. • LDH was capable to produce contrast in the T1 mode of MRI. • LDH were intercalated with folate, ibuprofen and gallate ions. - Abstract: A layered double hydroxide structure including dysprosium cations was prepared by co-precipitation. The nanoparticles showed a linear relationship with the reciprocal relaxation spin-lattice (T1) time of water protons which is reflected as contrast in aqueous suspensions analyzed by magnetic resonance imaging. The interlayer space of dysprosium containing LDH was successfully intercalated with folate, ibuprofen and gallate ions, which are key molecules for recognition of some cancer cells and treatment of diseases. The paramagnetic property of the dysprosium-containing LDH detected in this work beside the ability to transport drugs open up the opportunity to design theranostic materials in a single crystal phase with nanometric dimensions.

Dysprosium-containing layered double hydroxides nanoparticles intercalated with biologically active species as an approach for theranostic systems

International Nuclear Information System (INIS)

Arratia-Quijada, Jenny; Sánchez Jiménez, Cecilia; Gurinov, Andrey; Pérez Centeno, Armando; Ceja Andrade, Israel; Carbajal Arízaga, Gregorio Guadalupe

2016-01-01

Graphical abstract: - Highlights: • LDH structure including dysprosium was prepared by co-precipitation. • LDH was capable to produce contrast in the T1 mode of MRI. • LDH were intercalated with folate, ibuprofen and gallate ions. - Abstract: A layered double hydroxide structure including dysprosium cations was prepared by co-precipitation. The nanoparticles showed a linear relationship with the reciprocal relaxation spin-lattice (T1) time of water protons which is reflected as contrast in aqueous suspensions analyzed by magnetic resonance imaging. The interlayer space of dysprosium containing LDH was successfully intercalated with folate, ibuprofen and gallate ions, which are key molecules for recognition of some cancer cells and treatment of diseases. The paramagnetic property of the dysprosium-containing LDH detected in this work beside the ability to transport drugs open up the opportunity to design theranostic materials in a single crystal phase with nanometric dimensions.

Semiconductor composition containing iron, dysprosium, and terbium

Science.gov (United States)

Pooser, Raphael C.; Lawrie, Benjamin J.; Baddorf, Arthur P.; Malasi, Abhinav; Taz, Humaira; Farah, Annettee E.; Kalyanaraman, Ramakrishnan; Duscher, Gerd Josef Mansfred; Patel, Maulik K.

2017-09-26

An amorphous semiconductor composition includes 1 to 70 atomic percent iron, 15 to 65 atomic percent dysprosium, 15 to 35 atomic percent terbium, balance X, wherein X is at least one of an oxidizing element and a reducing element. The composition has an essentially amorphous microstructure, an optical transmittance of at least 50% in at least the visible spectrum and semiconductor electrical properties.

Synthesis, structural characterization and in vitro testing of dysprosium containing silica particles as potential MRI contrast enhancing agents

Energy Technology Data Exchange (ETDEWEB)

Chiriac, L.B.; Trandafir, D.L. [Faculty of Physics & National Magnetic Resonance Center, Babeş-Bolyai University, Cluj-Napoca, RO-400084 (Romania); Interdisciplinary Research Institute on Bio-Nano-Sciences & Faculty of Physics, Babeş-Bolyai University, Cluj-Napoca, RO-400084 (Romania); Turcu, R.V.F. [Faculty of Physics & National Magnetic Resonance Center, Babeş-Bolyai University, Cluj-Napoca, RO-400084 (Romania); Todea, M. [Interdisciplinary Research Institute on Bio-Nano-Sciences & Faculty of Physics, Babeş-Bolyai University, Cluj-Napoca, RO-400084 (Romania); Simon, S., E-mail: simons@phys.ubbcluj.ro [Faculty of Physics & National Magnetic Resonance Center, Babeş-Bolyai University, Cluj-Napoca, RO-400084 (Romania); Interdisciplinary Research Institute on Bio-Nano-Sciences & Faculty of Physics, Babeş-Bolyai University, Cluj-Napoca, RO-400084 (Romania)

2016-11-01

Highlights: • Dysprosium containing silica microparticles obtained by freeze and spray drying. • Higher structural units interconnection achieved in freeze vs. spray dried samples. • Dy occurance on the outermost layer of the microparticles evidenced by XPS. • Enhanced MRI contrast observed for freeze dried samples with 5% mol Dy{sub 2}O{sub 3}. - Abstract: The work is focused on synthesis and structural characterization of novel dysprosium-doped silica particles which could be considered as MRI contrast agents. Sol-gel derived silica rich particles obtained via freeze-drying and spray-drying processing methods were structurally characterized by XRD, {sup 29}Si MAS-NMR and XPS methods. The occurrence of dysprosium on the outermost layer of dysprosium containing silica particles was investigated by XPS analysis. The MRI contrast agent characteristics have been tested using RARE-T{sub 1} and RARE-T{sub 2} protocols. The contrast of MRI images delivered by the investigated samples was correlated with their local structure. Dysprosium disposal on microparticles with surface structure characterised by decreased connectivity of the silicate network units favours dark T{sub 2}-weighted MRI contrast properties.

Ethanolamine derivatives of dysprosium and holmium

International Nuclear Information System (INIS)

Gharia, K.S.; Singh, M.; Mathur, S.; Sankhla, B.S.

1981-01-01

The preparation and properties of dysprosium and holmium derivatives of mono-, di- and tri-ethanolamine derivatives are described. Compounds of general formulae: Ln(OPrsup(i)) 2 (mea), Ln(OPrsup(i))(mea) 2 , Ln(mea) 3 , Ln(OPrsup(i))(dea), Ln 2 (dea) 3 , Ln(dea)(deaH) and Ln(tea) (where Ln = Dy or Ho and mea, dea and tea are the anions of respective ethanolamine) were obtained and characterized by elemental analysis and IR spectra. (author)

Synthesis, characterization and sup 23 Na NMR shift studies of a novel dysprosium(III) crown ether texaphyrin

Energy Technology Data Exchange (ETDEWEB)

Sessler, J.L.; Mody, T.D. (Texas Univ., Austin, TX (United States). Dept. of Chemistry); Ramasamy, R.; Sherry, A.D. (Texas Univ., Dallas, TX (United States))

1992-05-01

The synthesis and characterization of a novel dysprosium(III) crown-ether texaphyrin (Dy(BCTxp)){sup 2+} is reported. This complex was designed to serve as a ditopic chelate for both dysprosium(III) and sodium cations. {sup 23}Sodium NMR spectroscopic studies indicates that titration of Na{sup +} with increasing concentrations of (Dy(BCTxp)){sup 2+} results in a shift toward higher frequency and gives a net hyperfine shift of 0.86 ppm. Sodium complexation is taking place into the crown subunit in (Dy(BCTxp)){sup 2+} and the degree of complexation is not reduced substantially by the positive charge on the dysprosium(III) portion of this binucleating system.

Dysprosium-containing layered double hydroxides nanoparticles intercalated with biologically active species as an approach for theranostic systems

KAUST Repository

Arratia-Quijada, Jenny

2015-10-23

A layered double hydroxide structure including dysprosium cations was prepared by co-precipitation. The nanoparticles showed a linear relationship with the reciprocal relaxation spin-lattice (T1) time of water protons which is reflected as contrast in aqueous suspensions analyzed by magnetic resonance imaging. The interlayer space of dysprosium containing LDH was successfully intercalated with folate, ibuprofen and gallate ions, which are key molecules for recognition of some cancer cells and treatment of diseases. The paramagnetic property of the dysprosium-containing LDH detected in this work beside the ability to transport drugs open up the opportunity to design theranostic materials in a single crystal phase with nanometric dimensions.

Dysprosium-containing layered double hydroxides nanoparticles intercalated with biologically active species as an approach for theranostic systems

KAUST Repository

Arratia-Quijada, Jenny; Sá nchez Jimé nez, Cecilia; Gurinov, Andrei; Pé rez Centeno, Armando; Ceja Andrade, Israel; Carbajal Arí zaga, Gregorio Guadalupe

2015-01-01

A layered double hydroxide structure including dysprosium cations was prepared by co-precipitation. The nanoparticles showed a linear relationship with the reciprocal relaxation spin-lattice (T1) time of water protons which is reflected as contrast in aqueous suspensions analyzed by magnetic resonance imaging. The interlayer space of dysprosium containing LDH was successfully intercalated with folate, ibuprofen and gallate ions, which are key molecules for recognition of some cancer cells and treatment of diseases. The paramagnetic property of the dysprosium-containing LDH detected in this work beside the ability to transport drugs open up the opportunity to design theranostic materials in a single crystal phase with nanometric dimensions.

Development and mastering of production of dysprosium hafnate as absorbing material for control rods of promising thermal neutron reactors

International Nuclear Information System (INIS)

Zakharov, A.V.; Risovany, V.D.; Muraleva, E.M.; Sokolov, V.F.

2011-01-01

The main advantages of dysprosium hafnate as an absorbing material for LWR control rods are the following: -) unlimited radiation resistance; - two absorbing components, Dy and Hf, increasing physical efficiency of the material compared to Dy 2 O 3 -TiO 2 and alloy 80% Ag - 15% In - 5% Cd; -) variability of physical efficiency by changing a composition, but maintaining other performance characteristics of the material; -) high process-ability due to the absence of phase transients and single-phase structure (solid solution); -) production of high density pellets. Lab-scale mastering of dysprosium hafnate pellets production showed a possibility of material synthesis using a solid-phase method, as well as of dysprosium hafnate pellets production by cold pressing and subsequent sintering. Within a whole range of examined compositions (23 mol% - 75 mol% Dy 2 O 3 ), a single-phase material with a highly radiation resistant fluorite-like structure was produced. Experiments on cold pressing and sintering of pellets confirmed a possibility of producing high quality dysprosium hafnate pellets from synthesized powder. A pilot batch of dysprosium hafnate pellets with standard sizes was produced. The standard sizes corresponded to the absorbing elements of the WWER-1000 control rods and met the main requirements to the absorbing element columns. The pilot batch size was approximately 6 kg. Acceptance testing of the pilot batch of dysprosium hafnate pellets was conducted, fulfillment of the requirements of technical conditions was checked and preirradiation properties of the pellets were examined. High quality of the produced pellets was confirmed, thus, demonstrating a real possibility of producing large batches of the dysprosium hafnate pellets. The next step is the production of test absorbing elements and cluster assemblies for the WWER-1000 control rods with their further installation for pilot operation at one of the Russian nuclear power plants

Dual responsive dysprosium-doped hydroxyapatite particles and toxicity reduction after functionalization with folic and glucuronic acids

Energy Technology Data Exchange (ETDEWEB)

Sánchez Lafarga, Ana Karen; Pacheco Moisés, Fermín P. [Departamento de Química, Universidad de Guadalajara, Marcelino García Barragán 1421, C.P. 44430, Guadalajara, Jalisco (Mexico); Gurinov, Andrey [Research Resources Center for Magnetic Resonance, Saint Petersburg State University, Universitetskij pr. 26, 198504 St. Petersburg (Russian Federation); Ortiz, Genaro Gabriel [Laboratorio Desarrollo-Envejecimiento, Enfermedades Neurodegenerativas, Centro de Investigación Biomédica de Occidente (CIBO), Instituto Mexicano de Seguro Social (IMSS), Guadalajara, Jalisco (Mexico); Carbajal Arízaga, Gregorio Guadalupe, E-mail: gregoriocarbajal@yahoo.com.mx [Departamento de Química, Universidad de Guadalajara, Marcelino García Barragán 1421, C.P. 44430, Guadalajara, Jalisco (Mexico)

2015-03-01

The development of probes for biomedical applications demands materials with low toxicity levels besides fluorescence or magnetic properties to be detected by confocal microscopes or MRI resonators. Several drug delivery systems or other biomedical materials prepared with hydroxyapatite have been proposed, however, toxicity effects might arise when the size of particles is nanometric. In this study, hydroxyapatite functionalized with glucuronic or folic acids presented lower oxidative stress, measured from lipoperoxides and nitric oxide indicators in rats than pure hydroxyapatite. In separated experiments, hydroxyapatite was doped with dysprosium cations by coprecipitation producing a single crystal phase with fluorescent properties easily visualized by confocal microscopy when excited at 488 nm. These particles also presented the ability to modify the proton relaxation time in T1 maps collected by magnetic resonance imaging. These modified hydroxyapatite nanoparticles could be candidates to design bimodal probes with low toxicity. - Highlights: • Hydroxyapatite functionalized with glucuronic acid reduced oxidative stress in rats. • Functionalization with folic acid reduced oxidative stress in rats. • Dysprosium doping does not affect the crystalline structure of hydroxyapatite. • Dysprosium doped particles are visible in fluorescent microscope. • Dysprosium doped particles act as MRI contrast agents.

Dual responsive dysprosium-doped hydroxyapatite particles and toxicity reduction after functionalization with folic and glucuronic acids

International Nuclear Information System (INIS)

Sánchez Lafarga, Ana Karen; Pacheco Moisés, Fermín P.; Gurinov, Andrey; Ortiz, Genaro Gabriel; Carbajal Arízaga, Gregorio Guadalupe

2015-01-01

The development of probes for biomedical applications demands materials with low toxicity levels besides fluorescence or magnetic properties to be detected by confocal microscopes or MRI resonators. Several drug delivery systems or other biomedical materials prepared with hydroxyapatite have been proposed, however, toxicity effects might arise when the size of particles is nanometric. In this study, hydroxyapatite functionalized with glucuronic or folic acids presented lower oxidative stress, measured from lipoperoxides and nitric oxide indicators in rats than pure hydroxyapatite. In separated experiments, hydroxyapatite was doped with dysprosium cations by coprecipitation producing a single crystal phase with fluorescent properties easily visualized by confocal microscopy when excited at 488 nm. These particles also presented the ability to modify the proton relaxation time in T1 maps collected by magnetic resonance imaging. These modified hydroxyapatite nanoparticles could be candidates to design bimodal probes with low toxicity. - Highlights: • Hydroxyapatite functionalized with glucuronic acid reduced oxidative stress in rats. • Functionalization with folic acid reduced oxidative stress in rats. • Dysprosium doping does not affect the crystalline structure of hydroxyapatite. • Dysprosium doped particles are visible in fluorescent microscope. • Dysprosium doped particles act as MRI contrast agents

Dysprosium-Catalyzed Growth of Single-Walled Carbon Nanotube Arrays on Substrates

Directory of Open Access Journals (Sweden)

Qian Yong

2009-01-01

Full Text Available Abstract In this letter, we report that dysprosium is an effective catalyst for single-walled carbon nanotubes (SWNTs growth via a chemical vapor deposition (CVD process for the first time. Horizontally superlong well-oriented SWNT arrays on SiO2/Si wafer can be fabricated by EtOH-CVD under suitable conditions. The structure and properties are characterized by scanning electron microscopy, transition electron microscopy, Raman spectroscopy and atomic force microscopy. The results show that the SWNTs from dysprosium have better structural uniformity and better conductivity with fewer defects. This rare earth metal provides not only an alternative catalyst for SWNTs growth, but also a possible method to generate high percentage of superlong semiconducting SWNT arrays for various applications of nanoelectronic device.

Dysprosium complexes with the tetraphenylporphyrin macrocyclic ligand; Complejos de disprosio con el ligante macrociclico tetrafenilporfirina

Energy Technology Data Exchange (ETDEWEB)

Martinez M, V.; Padilla, J.; Ramirez, F.M

1992-04-15

In this report, the results obtained on the synthesis, characterization and study of the chemical behavior of dysprosium complex with the acetylacetone chelating agent (Hacac) and the tetraphenylporphyrin macrocyclic ligand (H{sub 2}TFP) are given. Based on the literature but according to our necessities and interest, the appropriate methodology settled down from the synthesis of prime matters until the obtaining and characterization of the products. The acetyl acetonate complex was obtained of mono hydrated dysprosium [Dy(acac){sub 3}. H{sub 2}0] and trihydrated [Dy(acac){sub 3} .3 H{sub 2}0], the mono tetra phenyl porphyrinate [Dy(TFP)(acac). 2 ac] the double sandwich of the dysprosium porphyrinate [Dy(TFP){sub 2}] and the triple sandwich of the dysprosium porphyrinate [Dy(TFP){sub 3}. 2 TCB] (TCB = trichlorobenzene). Its were characterized by their melting points, solubility, IR, UV, TGA and DTA both first and besides the techniques already mentioned for NMR'H, RPE and Magnetic susceptibility the three last complexes. From the spectroscopic point of view, IR and RPE its suggested the existence of a complex of inverse mixed valence [Dy(TFP){sup 2-} (TFP) {sup 1-}] for the Dy(TFP){sub 2} as a result of the existence of the free radical (TFP' {sup 1-} and that it was not in none of the other porphyrin compounds. In the NMR'H spectra of the compounds were not observed signals in the region from 0 to 10 ppm that which shows that the dysprosium complexes in special those of the porphyrin type are highly paramagnetic and its could be used as displacement reagents, creators of images and contrast agents of great utility in these days in studies of NMR, technique today by today used in medical diagnoses. (Author)

Dysprosium complexes with the tetraphenylporphyrin macrocyclic ligand; Complejos de disprosio con el ligante macrociclico tetrafenilporfirina

Energy Technology Data Exchange (ETDEWEB)

Martinez M, V; Padilla, J; Ramirez, F M

1992-04-15

In this report, the results obtained on the synthesis, characterization and study of the chemical behavior of dysprosium complex with the acetylacetone chelating agent (Hacac) and the tetraphenylporphyrin macrocyclic ligand (H{sub 2}TFP) are given. Based on the literature but according to our necessities and interest, the appropriate methodology settled down from the synthesis of prime matters until the obtaining and characterization of the products. The acetyl acetonate complex was obtained of mono hydrated dysprosium [Dy(acac){sub 3}. H{sub 2}0] and trihydrated [Dy(acac){sub 3} .3 H{sub 2}0], the mono tetra phenyl porphyrinate [Dy(TFP)(acac). 2 ac] the double sandwich of the dysprosium porphyrinate [Dy(TFP){sub 2}] and the triple sandwich of the dysprosium porphyrinate [Dy(TFP){sub 3}. 2 TCB] (TCB = trichlorobenzene). Its were characterized by their melting points, solubility, IR, UV, TGA and DTA both first and besides the techniques already mentioned for NMR'H, RPE and Magnetic susceptibility the three last complexes. From the spectroscopic point of view, IR and RPE its suggested the existence of a complex of inverse mixed valence [Dy(TFP){sup 2-} (TFP) {sup 1-}] for the Dy(TFP){sub 2} as a result of the existence of the free radical (TFP' {sup 1-} and that it was not in none of the other porphyrin compounds. In the NMR'H spectra of the compounds were not observed signals in the region from 0 to 10 ppm that which shows that the dysprosium complexes in special those of the porphyrin type are highly paramagnetic and its could be used as displacement reagents, creators of images and contrast agents of great utility in these days in studies of NMR, technique today by today used in medical diagnoses. (Author)

Study on the electrochemical of the metal deposition from ionic liquids for lithium, titanium and dysprosium

International Nuclear Information System (INIS)

Berger, Claudia A.

2017-01-01

The thesis was aimed to the characterization of electrochemically deposited film of lithium, titanium and dysprosium on Au(111) from different ionic liquids, finally dysprosium on neodymium-iron-boron magnate for industrial applications. The investigation of the deposits were performed using cyclic voltametry, in-situ scanning tunneling microscopy, electrochemical quartz microbalance, XPS and Auger electron spectroscopy. The sample preparation is described in detail. The deposition rate showed a significant temperature dependence.

Synthesis and X-ray structure of the dysprosium(III) complex derived ...

African Journals Online (AJOL)

Synthesis and X-ray structure of the dysprosium(III) complex derived from the ligand 5-chloro-1 ... Bulletin of the Chemical Society of Ethiopia ... synthesized and its crystal structure determined by single X-ray diffraction at room temperature.

Phosphor Dysprosium-Doped Layered Double Hydroxides Exchanged with Different Organic Functional Groups

Directory of Open Access Journals (Sweden)

David Ricardo Martínez Vargas

2013-01-01

Full Text Available The layers of a Zn/Al layered double hydroxide (LDH were doped with Dy3+ cations. Among some compositions, the Zn2+ : Al3+ : Dy3+ molar ratio equal to 30 : 9 : 1 presented a single crystalline phase. Organic anions with carboxylic, amino, sulfate, or phosphate functional groups were intercalated as single layers between LDH layers as confirmed by X-ray diffraction and infrared spectroscopy. Photoluminescence spectra of the nitrate intercalated LDH showed a wide emission band with strong intensity in the yellow region (around 574 nm, originated due to symmetry distortion of the octahedral coordination in dysprosium centers. Moreover, a broad red band emission was also detected apparently due to the presence of zinc oxide. The distorted symmetry of the dysprosium coordination environment, also confirmed by X-ray photoelectron spectroscopy analysis, was modified after the intercalation with phenyl phosphonate (PP, aspartate (Asp, adipate (Adip, and serinate (Ser anions; the emission as measured from PL spectra of these LDH was more intense in the blue region (ca. 486 nm, thus indicating an increase in symmetry of dysprosium octahedrons. The red emission band from zinc oxide kept the same intensity after intercalation of dodecyl sulfate (DDS. An additional emission of unknown origin at λ = 767 nm was present in all LDHs.

Neutronography of an intermediate phase in dysprosium near the Neel point

Energy Technology Data Exchange (ETDEWEB)

Bessergenev, V G; Gogava, V V; Kovalevskaya, Yu A; Mandzhavidze, A G; Fedorov, V M; Shilo, S I

1985-11-25

Neutronographical study of dysprosium magnetic structure near the point of magnetic disordering depending on thermal prehistory of the sample is carried out. Intermediate vortex phase transformed then into the helical one is shown to occur from the paramagnetic phase under cooling.

Sandwich-type tetrakis(phthalocyaninato) dysprosium-cadmium quadruple-decker SMM.

Science.gov (United States)

Wang, Hailong; Qian, Kang; Wang, Kang; Bian, Yongzhong; Jiang, Jianzhuang; Gao, Song

2011-09-14

Homoleptic tetrakis[2,3,9,10,16,17,23,24-octa(butyloxy)phthalocyaninato] dysprosium-cadmium quadruple-decker complex 1 was isolated in relatively good yield of 43% from a simple one-pot reaction. This compound represents the first sandwich-type tetrakis(phthalocyaninato) rare earth-cadmium quadruple-decker SMM that has been structurally characterized. This journal is © The Royal Society of Chemistry 2011

Synovectomy of the rheumatoid knee using intra-articular injection of dysprosium-165-ferric hydroxide macroaggregates

International Nuclear Information System (INIS)

Sledge, C.B.; Zuckerman, J.D.; Shortkroff, S.; Zalutsky, M.R.; Venkatesan, P.; Snyder, M.A.; Barrett, W.P.

1987-01-01

One hundred and eleven patients who had seropositive rheumatoid arthritis and persistent synovitis of the knee were treated with intra-articular injection of 270 millicuries of dysprosium-165 bound to ferric hydroxide macroaggregates. A two-year follow-up was available for fifty-nine of the treated knees. Thirty-nine had a good result; nine, a fair result; and eleven, a poor result. Of the twenty-five knees that had Stage-I radiographic changes, nineteen had a good result. Of the thirty-four knees that had Stage-II radiographic changes, twenty showed a good result. Systemic spread of the radioactivity from the injected joint was minimum. The mean whole-body dose was calculated to be 0.3 rad and that to the liver twenty-four hours after injection, 3.2 rads. The results indicated that dysprosium-165-ferric hydroxide macroaggregate is an effective agent for performing radiation synovectomy, particularly in knees that have Stage-I radiographic changes. Because of the minimum rate of systemic spread of the dysprosium-165, it offers a definite advantage over agents that previously have been used

On polymorphism of dysprosium trichloride

International Nuclear Information System (INIS)

Zakiryanova, Irina D.; Khokhlov, Vladimir A.; Salyulev, Alexander B.; Korzun, Iraida V.

2015-01-01

For the first time, the structure of crystalline DyCl 3 over a wide temperature range from room temperature to melting point was studied by Raman spectroscopy. The phonon modes (cm -1 ) of dysprosium trichloride (monoclinic crystal lattice of AlCl 3 type, Z = 4, CN = 6) at room temperature are 257 (A 1g ), 201 (E g ), 112 (E g ), 88 (A 1g ), and 63 (E g ). The monoclinic structure of the crystalline DyCl 3 C 2h 3 symmetry was found to remain constant over the studied temperature range. No polymorphic transformation in the solid state was detected. Gravimetry, calorimetry, and mass spectrometry have been used in addition to support the conclusions made on the basis of Raman spectroscopic data.

Mixed (phthalocyaninato)(Schiff-base) di-dysprosium sandwich complexes. Effect of magnetic coupling on the SMM behavior.

Science.gov (United States)

Wang, Hailong; Liu, Chenxi; Liu, Tao; Zeng, Suyuan; Cao, Wei; Ma, Qi; Duan, Chunying; Dou, Jianmin; Jiang, Jianzhuang

2013-11-21

Reaction between Schiff-base ligand and half-sandwich complex M(Pc)(acac) led to the isolation of new sandwich-type mixed (phthalocyaninato)(Schiff-base) di-lanthanide compounds M2(Pc)2(L)H2O (M = Dy, Gd) (1, 2) [H2Pc = metal free phthalocyanine, Hacac = acetylacetone, H2L = N,N'-bis(3-methyloxysalicylidene)benzene-1,2-diamine] with the triple-decker molecular structure clearly revealed by single crystal X-ray diffraction analysis. For the comparative studies, sandwich triple-decker analogues with pure Schiff-base ligand M2(L)3H2O (M = Dy, Gd) (3, 4) were also prepared. Dynamic magnetic measurement result reveals the single-molecule magnet (SMM) nature of the di-dysprosium derivative 1, while the static magnetic investigation over both pure and the diamagnetic diluted samples of this compound discloses the interionic ferromagnetic coupling between the two dysprosium ions, which in turn effectively suppresses the QTM and enhances the energy barrier of this SMM. Nevertheless, comparative studies over the static magnetic properties of the di-dysprosium triple-decker complexes 1 and 3 indicate the stronger magnetic coupling between the two lanthanide ions in mixed (phthalocyaninato)(Schiff-base) species than in the pure Schiff-base triple-decker analogue, suggesting the special coordination sphere around the dysprosium ions in the former compound over the latter one on the more intense inter-ionic ferromagnetic coupling. As a very small step towards understanding the structure-property relationship, the present result will be surely helpful for the design and synthesis of the multinuclear lanthanide-based SMMs with good properties.

On polymorphism of dysprosium trichloride

Energy Technology Data Exchange (ETDEWEB)

Zakiryanova, Irina D.; Khokhlov, Vladimir A.; Salyulev, Alexander B.; Korzun, Iraida V. [RAS Ural Branch, Ekaterinburg (Russian Federation). Institute of High-Temperature Electrochemistry

2015-07-01

For the first time, the structure of crystalline DyCl{sub 3} over a wide temperature range from room temperature to melting point was studied by Raman spectroscopy. The phonon modes (cm{sup -1}) of dysprosium trichloride (monoclinic crystal lattice of AlCl{sub 3} type, Z = 4, CN = 6) at room temperature are 257 (A{sub 1g}), 201 (E{sub g}), 112 (E{sub g}), 88 (A{sub 1g}), and 63 (E{sub g}). The monoclinic structure of the crystalline DyCl{sub 3} C{sub 2h}{sup 3} symmetry was found to remain constant over the studied temperature range. No polymorphic transformation in the solid state was detected. Gravimetry, calorimetry, and mass spectrometry have been used in addition to support the conclusions made on the basis of Raman spectroscopic data.

Systematic study on surface and magnetostructural changes in Mn-substituted dysprosium ferrite by hydrothermal method

Energy Technology Data Exchange (ETDEWEB)

Rekha, G. [Department of Physics, College of Engineering Guindy, Anna University, Sardar Patel Road, Chennai 600025 (India); Tholkappiyan, R. [Department of Physics, College of Engineering Guindy, Anna University, Sardar Patel Road, Chennai 600025 (India); Department of Physics, College of Science, UAE University, Al-Ain 15551 (United Arab Emirates); Vishista, K., E-mail: raovishista@gmail.com [Department of Physics, College of Engineering Guindy, Anna University, Sardar Patel Road, Chennai 600025 (India); Hamed, Fathalla [Department of Physics, College of Science, UAE University, Al-Ain 15551 (United Arab Emirates)

2016-11-01

Highlights: • Garnet type Dy{sub 3}Fe{sub 5-x}Mn{sub x}O{sub 12} (x = 0–0.06) nanoparticles of 88.4–86.8 nm were synthesized by hydrothermal method. • The Dy, Mn, Fe and O elements in the ferrites were confirmed from XPS. • The multiple oxidation states of Fe and Mn ions, bonding energy and cationic distributions of the samples were examined by XPS. • The magnetic property shows ferromagnetic behavior from VSM technique. • The results from these studies are correlated with respect to Mn dopant. - Abstract: Dysprosium iron garnets are of scientific importance because of the wide range of magnetic properties that can be obtained in substituting dysprosium by a rare earth metal. In the present work, the effect of Mn substitution on magnetostructural changes in dysprosium ferrite nanoparticles is studied. Highly crystalline pure and Mn doped dysprosium ferrite nanoparticles were synthesized by hydrothermal method. The samples were calcined at 1100 °C for 2 h in air atmosphere which is followed by characterization using XRD, FT-IR analysis, SEM, XPS and VSM. The average crystallite size of synthesized samples were calculated by X-ray diffraction falls in the range of 88.4–86.8 nm and was found to be in cubic garnet structure. For further investigation of the structure and corresponding changes in the tetrahedral and octahedral stretching vibrational bonds, FT-IR was used. The synthesized samples consist of multiple oxidation (Fe{sup 3+} and Fe{sup 2+}) states for Fe ions and (Mn{sup 3+} and Mn{sup 2+}) Mn ions analyzed in three ways of Fe 2p and Mn 2p spectra from the XPS analysis. With respect to Mn dopant in Dy{sub 3}Fe{sub 5}O{sub 12}, the cationic distributions of elements were discussed from high resolution XPS spectra by peak position and shift, area, width. To find out the porous/void surface morphology of the sample, scanning electron microscopy was used. From XPS analysis, the presence of elements (Dy, Mn, Fe and O) and their composition in the

Dysprosium (holmium) determination in the presence of erbium and dysprosium (holmium, erbium) determination in the presence of cerium

International Nuclear Information System (INIS)

Tolubara, A.I.; Kochubej, A.I.; Usatenko, Yu.I.

1978-01-01

Effect of salicylic acid upon complex formation in the systems REE - boronsulfoalizarinate, REE - oxine and REE - boronsulfoalizarinate - oxine is investigated. Comparison of optical characteristics of the above systems in the absence and in the presence of salicylic acid is carried out. It is established that in all the cases the effect of salicylic acid depends both on the nature of REE and the ratio of all the components of the system. Under certain conditions the given dependence is observed only for erbium complexes. Extraction-photometric methods of dysprosium and holmium determination in the presence of equal erbium amounts, as well as holmium and erbium determination in the presence of cerium equal amounts is developed

Dysprosium (holmium) determination in the presence of erbium and dysprosium (holmium, erbium) determination in the presence of cerium

Energy Technology Data Exchange (ETDEWEB)

Tolubara, A I; Kochubei, A I; Usatenko, Yu I

1978-01-01

Effect of salicylic acid upon complex formation in the systems REE - boronsulfoalizarinate, REE - oxine and REE - boronsulfoalizarinate - oxine is investigated. Comparison of optical characteristics of the above systems in the absence and in the presence of salicylic acid is carried out. It is established that in all the cases the effect of salicylic acid depends both on the nature of REE and the ratio of all the components of the system. Under certain conditions the given dependence is observed only for erbium complexes. Extraction-photometric methods of dysprosium and holmium determination in the presence of equal erbium amounts, as well as holmium and erbium determination in the presence of cerium equal amounts is developed.

{Delta}I = 2 energy staggering in normal deformed dysprosium nuclei

Energy Technology Data Exchange (ETDEWEB)

Riley, M.A.; Brown, T.B.; Archer, D.E. [Florida State Univ., Tallahassee, FL (United States)] [and others

1996-12-31

Very high spin states (I{ge}50{Dirac_h}) have been observed in {sup 155,156,157}Dy. The long regular band sequences, free from sharp backbending effects, observed in these dysprosium nuclei offer the possibility of investigating the occurence of any {Delta}I = 2 staggering in normal deformed nuclei. Employing the same analysis techniques as used in superdeformed nuclei, certain bands do indeed demonstrate an apparent staggering and this is discussed.

Resonance ionization spectroscopy in dysprosium

Energy Technology Data Exchange (ETDEWEB)

Studer, D., E-mail: dstuder@uni-mainz.de; Dyrauf, P.; Naubereit, P.; Heinke, R.; Wendt, K. [Johannes Gutenberg-Universität Mainz, Institut für Physik (Germany)

2017-11-15

We report on resonance ionization spectroscopy (RIS) of high-lying energy levels in dysprosium. We developed efficient excitation schemes and re-determined the first ionization potential (IP) via analysis of Rydberg convergences. For this purpose both two- and three-step excitation ladders were investigated. An overall ionization efficiency of 25(4) % could be demonstrated in the RISIKO mass separator of Mainz University, using a three-step resonance ionization scheme. Moreover, an extensive analysis of the even-parity 6sns- and 6snd-Rydberg-series convergences, measured via two-step excitation was performed. To account for strong perturbations in the observed s-series, the approach of multichannel quantum defect theory (MQDT) was applied. Considering all individual series limits we extracted an IP-value of 47901.76(5) cm{sup −1}, which agrees with the current literature value of 47901.7(6) cm{sup −1}, but is one order of magnitude more precise.

Simultaneous determination of dysprosium, holmium and erbium in high purity rare earth oxides by second order derivative spectrophotometry

International Nuclear Information System (INIS)

Anbu, M.; Prasada Rao, T.; Iyer, C. S. P.; Damodaran, A. D.

1996-01-01

High purity individual rare earth oxides are increasingly used as major components in lasers (Y 2 O 3 ), phosphors (YVO 3 , Eu 2 O 3 ), magnetic bubble memory films (Gd 2 O 3 ) and refractive-index lenses and fibre optics (La 2 O 3 ). The determination of individual lanthanides in high purity rare earth oxides is a more important and difficult task. This paper reports the utilization of higher order derivative spectrophotometry for the simultaneous determination of dysprosium, holmium and erbium in high purity rare earth oxides. The developed procedure is simple, reliable and allows the determination of 0.001 to 0.2% of dysprosium, holmium and erbium in several rare earth. (author). 9 refs, 2 figs, 2 tabs

Terbium and dysprosium complexes luminescence at low temperatures

Energy Technology Data Exchange (ETDEWEB)

Meshkova, S B; Kravchenko, T B; Kononenko, L.I.; Poluehktov, N S [AN Ukrainskoj SSR, Odessa. Fiziko-Khimicheskij Inst.

1979-01-01

The variation is studied of the luminescence intensity of terbium and dysprosium complexes used in the analysis as solutions are cooled down to the liquid nitrogen temperature. Three groups of methods have been studied: observation of fluorescence of aqueous solutions, precipitate and extract suspensions in organic solvents. The brightest luminescence and greatest increase in luminescence intensity are observed at freezing of complex solvents with 1,2-dioxybenzene-3,5-disulfonic acid (DBSA) and iminodiacetic acid (IDA) and DBSA+EDTA, as well as in the case of benzene extracting of complexes with phenanthroline and salicylic acid. Otherwise the intensity increases 2-14-fold and for the complex of terbium with acetoacetic ester 36-fold.

A model for additive transport in metal halide lamps containing mercury and dysprosium tri-iodide

NARCIS (Netherlands)

Beks, M.L.; Haverlag, M.; Mullen, van der J.J.A.M.

2008-01-01

The distribution of additives in a metal halide lamp is examined through numerical modelling. A model for a lamp containing sodium iodide additives has been modified to study a discharge containing dysprosium tri-iodide salts. To study the complex chemistry the method of Gibbs minimization is used

The application of x-ray spectrometry to isotopic-source activation analysis of dysprosium and holmium

International Nuclear Information System (INIS)

Pillay, A.E.; Mboweni, R.C.M.

1990-01-01

A novel aspect of activation analysis is described for the determination of dysprosium and holmium at low concentrations. The method involves the measurement of K x-rays from radionuclides produced by thermal neutron activation using a 1 mg 252 Cf source. The basis for elemental selection depends largely on the demand for analysis and on the existence of favourable nuclear properties for the production of a practicable x-ray yield. A full appraisal of the analytical potential of the method is presented with particular emphasis on its application to geological matrices. The sensitivity was optimised by employing a detector that was particularly effective at photon energies below 150 keV. Analytical conditions are demonstrated for the elements of interest over a wide range of concentrations in small powdered samples. The investigation formed the basis of a feasibility study to establish if the application could be developed for the routine off-line determination of dysprosium and holmium using an isotopic-neutron source. (author)

On-line complexation/cloud point preconcentration for the sensitive determination of dysprosium in urine by flow injection inductively coupled plasma-optical emission spectrometry

International Nuclear Information System (INIS)

Ortega, Claudia; Cerutti, Soledad; Silva, Maria F.; Olsina, Roberto A.; Martinez, Luis D.

2003-01-01

An on-line dysprosium preconcentration and determination system based on the hyphenation of cloud point extraction (CPE) to flow injection analysis (FIA) associated with ICP-OES was studied. For the preconcentration of dysprosium, a Dy(III)-2-(5-bromo-2-pyridylazo)-5-diethylaminophenol complex was formed on-line at pH 9.22 in the presence of nonionic micelles of PONPE-7.5. The micellar system containing the complex was thermostated at 30 C in order to promote phase separation, and the surfactant-rich phase was retained in a microcolumn packed with cotton at pH 9.2. The surfactant-rich phase was eluted with 4 mol L -1 nitric acid at a flow rate of 1.5 mL min -1 , directly in the nebulizer of the plasma. An enhancement factor of 50 was obtained for the preconcentration of 50 mL of sample solution. The detection limit value for the preconcentration of 50 mL of aqueous solution of Dy was 0.03 μg L -1 . The precision for 10 replicate determinations at the 2.0 μg L -1 Dy level was 2.2% relative standard deviation (RSD), calculated from the peak heights obtained. The calibration graph using the preconcentration system for dysprosium was linear with a correlation coefficient of 0.9994 at levels near the detection limits up to at least 100 μg L -1 . The method was successfully applied to the determination of dysprosium in urine. (orig.)

Incinerator carryover tests with dysprosium as a stand-in for plutonium

International Nuclear Information System (INIS)

Hooker, R.L.

1981-11-01

A full-scale (5 kg/h) incinerator is being tested with nonradioactive feed materials which simulate SRP-generator combustible transuranic wastes. The incinerator is two-stage and is designed to provide relatively quiescent conditions in the primary chamber where the ash is formed. This feature should minimize entrainment of Pu-bearing particles into the off-gas system. A series of runs have been completed in which incinerator feed was spiked with dysprosium to simulate Pu. Carryover of Dy into the off-gas system was found to be low (about 1/4%). 4 figures, 3 tables

Selenium Sulfide

Science.gov (United States)

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

Neutron diffraction investigations of the superionic conductors lithium sulfide and sodium sulfide

International Nuclear Information System (INIS)

Altorfer, F.

1990-03-01

Statics and dynamics of the superionic conductors lithium sulfide and sodium sulfide were investigated using the following experimental methods: elastic scattering on sodium sulfide powder in the temperature range 20 - 1000 C, elastic scattering on a lithium sulfide single crystal in the temperature range 20 - 700 C, inelastic scattering on a 7 Li 2 S single crystal at 10 K. 34 figs., 2 tabs., 10 refs

Graphite furnace atomic absorption spectrometry with a tantalum boat for the determination of yttrium, samarium, and dysprosium in a mish metal

International Nuclear Information System (INIS)

Daidoji, Hidehiro; Tamura, Shohei

1982-01-01

The determination of yttrium, samarium, and dysprodium by means of graphite-furnace atomic absorption spectrometry (AAS) was studied by a tantalum boat inserted into a graphite tube atomizer. These elements could not be determined by the use of a commercial graphite tube, In the atomization from a tantalum boat, better analytical sensitivities and negligible memory effects for these rare earths are obtained. The analytical sensitivities of yttrium, samarium, and dysprodium with the tantalum boat were 0.60 ng, 0.86 ng, and 0.17 ng respectively. This method was applied for the determination of yttrium, samarium, and dysprosium in a mish metal. The measurements were performed with slightly acidified solutions (0.01 mol dm 3 HCI or HNO 3 ). The sensitivities and the precisions for these elements decreased with increasing acid concentration. An enhancement in the sensitivities of yttrium and dysprosium upon the addition of a large excess of lanthanum, neodymium, and praseodymium salts were observed. The yttrium, samarium, and dysprosium in a mish metal were determined with both analytical curves of standard solutions containing an excess of lanthanum, cerium, and neodymium ions and of the standard addition. The precisions for this work were in the 3 - 9.3% range. (author)

Analysis of the x-ray spectrum emitted by laser-produced plasma of dysprosium

International Nuclear Information System (INIS)

Marcus, Gilad; Louzon, Einat; Henis, Zohar; Maman, Shlomo; Mandelbaum, Pinchas

2007-01-01

A detailed analysis of the x-ray spectrum (5-10.2 A ring ) emitted by laser-produced plasma of dysprosium (Dy) is given using ab initio calculations with the HULLAC relativistic code and isoelectronic trends. Resonance 3d-4p, 3d-nf (n=4 to 7), 3p-4s, and 3p-4d transitions of Ni I-like Dy XXXIX and neighboring ion satellite transitions (from Dy XXXIV to Dy XL) are identified

Dosimetric properties of dysprosium doped calcium magnesium borate glass subjected to Co-60 gamma ray

Energy Technology Data Exchange (ETDEWEB)

Omar, R. S., E-mail: ratnasuffhiyanni@gmail.com; Wagiran, H., E-mail: husin@utm.my; Saeed, M. A. [Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, 81310 Johor Bahru (Malaysia)

2016-01-22

Thermoluminescence (TL) dosimetric properties of dysprosium doped calcium magnesium borate (CMB:Dy) glass are presented. This study is deemed to understand the application of calcium as the modifier in magnesium borate glass with the presence of dysprosium as the activator to be performed as TL dosimeter (TLD). The study provides fundamental knowledge of a glass system that may lead to perform new TL glass dosimetry application in future research. Calcium magnesium borate glass systems of (70-y) B{sub 2}O{sub 3} − 20 CaO – 10 MgO-(y) Dy{sub 2}O{sub 3} with 0.05  mol % ≤ y ≤ 0.7  mol % of dyprosium were prepared by melt-quenching technique. The amorphous structure and TL properties of the prepared samples were determined using powder X-ray diffraction (XRD) and TL reader; model Harshaw 4500 respectively. The samples were irradiated to Co-60 gamma source at a dose of 50 Gy. Dosimetric properties such as annealing procedure, time temperature profile (TTP) setting, optimization of Dy{sub 2}O{sub 3} concentration of 0.5 mol % were determined for thermoluminescence dosimeter (TLD) reader used.

Kinetic stability of the dysprosium(3) complex with tetraazaporphine in acetic acid-water and acetic acid-methanol mixtures

International Nuclear Information System (INIS)

Khelevina, O.G.; Vojnov, A.A.

1999-01-01

Water-soluble dysprosium tetraazaporphine with acetylacetonate-ion as extraligand is synthesized for the first time. Its kinetic stability in acetic acid solutions is investigated. It is shown that the complex is dissociated with formation of free tetraazaporphine. Kinetic parameters of dissociation reaction are determined [ru

Incorporation of dysprosium ions into PbTiO3 ferroelectric ceramic system

Directory of Open Access Journals (Sweden)

A. Peláiz-Barranco

2015-03-01

Full Text Available A structural analysis concerning the incorporation of dysprosium into A- and/or B-sites of the lead titanate is shown. The two "boundary" refinements are presented, i.e., Dy2+ substitutes for Pb2+ (Dy3+ substitutes for Ti4+ and Dy3+ substitutes for Pb2+ (Dy3+ substitutes for Ti4+. The results offer quantitative information about the incorporation into both crystallographic sites. The increase of Dy3+ fraction into B-site provides the increase of the Ti4+ atomic displacement along the [001] direction and the tetragonal distortion.

Transient Kinetic Analysis of Hydrogen Sulfide Oxidation Catalyzed by Human Sulfide Quinone Oxidoreductase*

Science.gov (United States)

Mishanina, Tatiana V.; Yadav, Pramod K.; Ballou, David P.; Banerjee, Ruma

2015-01-01

The first step in the mitochondrial sulfide oxidation pathway is catalyzed by sulfide quinone oxidoreductase (SQR), which belongs to the family of flavoprotein disulfide oxidoreductases. During the catalytic cycle, the flavin cofactor is intermittently reduced by sulfide and oxidized by ubiquinone, linking H2S oxidation to the electron transfer chain and to energy metabolism. Human SQR can use multiple thiophilic acceptors, including sulfide, sulfite, and glutathione, to form as products, hydrodisulfide, thiosulfate, and glutathione persulfide, respectively. In this study, we have used transient kinetics to examine the mechanism of the flavin reductive half-reaction and have determined the redox potential of the bound flavin to be −123 ± 7 mV. We observe formation of an unusually intense charge-transfer (CT) complex when the enzyme is exposed to sulfide and unexpectedly, when it is exposed to sulfite. In the canonical reaction, sulfide serves as the sulfur donor and sulfite serves as the acceptor, forming thiosulfate. We show that thiosulfate is also formed when sulfide is added to the sulfite-induced CT intermediate, representing a new mechanism for thiosulfate formation. The CT complex is formed at a kinetically competent rate by reaction with sulfide but not with sulfite. Our study indicates that sulfide addition to the active site disulfide is preferred under normal turnover conditions. However, under pathological conditions when sulfite concentrations are high, sulfite could compete with sulfide for addition to the active site disulfide, leading to attenuation of SQR activity and to an alternate route for thiosulfate formation. PMID:26318450

Transient Kinetic Analysis of Hydrogen Sulfide Oxidation Catalyzed by Human Sulfide Quinone Oxidoreductase.

Science.gov (United States)

Mishanina, Tatiana V; Yadav, Pramod K; Ballou, David P; Banerjee, Ruma

2015-10-09

The first step in the mitochondrial sulfide oxidation pathway is catalyzed by sulfide quinone oxidoreductase (SQR), which belongs to the family of flavoprotein disulfide oxidoreductases. During the catalytic cycle, the flavin cofactor is intermittently reduced by sulfide and oxidized by ubiquinone, linking H2S oxidation to the electron transfer chain and to energy metabolism. Human SQR can use multiple thiophilic acceptors, including sulfide, sulfite, and glutathione, to form as products, hydrodisulfide, thiosulfate, and glutathione persulfide, respectively. In this study, we have used transient kinetics to examine the mechanism of the flavin reductive half-reaction and have determined the redox potential of the bound flavin to be -123 ± 7 mV. We observe formation of an unusually intense charge-transfer (CT) complex when the enzyme is exposed to sulfide and unexpectedly, when it is exposed to sulfite. In the canonical reaction, sulfide serves as the sulfur donor and sulfite serves as the acceptor, forming thiosulfate. We show that thiosulfate is also formed when sulfide is added to the sulfite-induced CT intermediate, representing a new mechanism for thiosulfate formation. The CT complex is formed at a kinetically competent rate by reaction with sulfide but not with sulfite. Our study indicates that sulfide addition to the active site disulfide is preferred under normal turnover conditions. However, under pathological conditions when sulfite concentrations are high, sulfite could compete with sulfide for addition to the active site disulfide, leading to attenuation of SQR activity and to an alternate route for thiosulfate formation. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Proton NMR relaxivity of blood samples in the presence of some gadolinium and dysprosium compounds

International Nuclear Information System (INIS)

Coroiu, I.; Darabont, Al.; Bogdan, M.

1999-01-01

The use of some new compounds in MRI tissue and blood characterisation based on nuclear spin relaxation time measurements cannot be sustained until the molecular sources of these variations are understood. Tissues and blood are complex molecular systems with complex NMR properties. A better comprehension of the molecular basis of relaxation offers the possibility to predict the changes expected for a given pathology. The purpose of this contribution is to evidence the different relaxation characteristics of some gadolinium and dysprosium compounds in the presence and absence of the blood and to give a possible explanation about the molecular processes that cause occurrence of changes. Some gadolinium and dysprosium compounds such as: Gd-CIT (gadolinium citrate), Dy-DTPA (DTPA-diethylenetriamine pentaacetic acid), iron oxide - gadolinium oxide (or dysprosium oxide)- dextran complexes were prepared. The longitudinal T 1 -1 and transverse T 2 -1 'relaxation rates' measurements have been carried out as a function of molar concentrations. All measurements have been made at room temperature (about 25 deg.C) and the proton Larmor frequency ν o = 90 MHz. The pulsed NMR spectrometer utilised was a commercial Bruker SXP4/100 spectrometer. Transverse relaxation rate measurements have been made using the Carr-Purcell method, while longitudinal relaxation rate measurements using the inversion recovery pulse sequence, 180 angle-τ-90 angle. The accuracy was about 2-3% for the longitudinal relaxation rates and about 5-7% for the transverse relaxation rates. R 1 and R 2 relaxivities, in mM -1 s -1 were determined from the least square determination of the slopes of plots 1/T 1,2 versus compound molar concentration, using at least five independent measurements at several concentrations between 0 and 2 mM. Increased R 2 relaxivity observed for dysprosium compounds in the blood presence can be explained by PRE effect. The largest gain in R 2 relaxivity seems to imply a noncovalent

SULFIDE MINERALS IN SEDIMENTS

Science.gov (United States)

The formation processes of metal sulfides in sediments, especially iron sulfides, have been the subjects of intense scientific research because of linkages to the global biogeochemical cycles of iron, sulfur, carbon, and oxygen. Transition metal sulfides (e.g., NiS, CuS, ZnS, Cd...

Photoluminescence study on amino functionalized dysprosium oxide-zinc oxide composite bifunctional nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Joseph, Aswathy; Praveen, G.L; Abha, K.; Lekha, G.M [Department of Chemistry, University of Kerala, Kariavattom, Kerala 695581 (India); George, Sony, E-mail: emailtosony@gmail.com [Department of Chemistry, University of Kerala, Kariavattom, Kerala 695581 (India)

2012-08-15

An organic dispersion of 9-15 nm size stable dysprosium oxide incorporated zinc oxide nanocomposites exhibiting luminescence in the visible region has been synthesised by a wet chemical precipitation technique at room temperature. Tetraethoxysilane TEOS [(C{sub 2}H{sub 5}O){sub 4}Si], (3-aminopropyl) trimethoxysilane (APTS) and a 1:1 mixture of TEOS-APTS have been used as capping agents to control the particle size as well as to achieve uniform dispersion of composite nanoparticles in methanol medium. X-ray diffractometer (XRD) analysis reveals the formation phase of amino-functionalised colloidal dysprosium oxide incorporated ZnO composite nanoparticles to be of zincite structure. The Transmission Electron Microscopy (TEM) images show that the particles are spheroids in shape, having average crystalline sizes ranging from 9 to 15 nm. The photoluminescence (PL) observed in these composites has been attributed to the presence of near band edge excitonic emission and existence of defect centres. The time correlated single photon counting studies of the composite nanoparticles exhibited three decay pathways. The enhanced PL emission intensity of solid state fluorescence spectra of samples is attributed to the absence of vibrational relaxation process. - Highlights: Black-Right-Pointing-Pointer Nano-composites are synthesised using a one step wet chemical precipitation method. Black-Right-Pointing-Pointer A significant fluorescence life time of 8.25 ns is obtained for the nano-composite. Black-Right-Pointing-Pointer Nano-composite particles exhibited pale yellow fluorescence rather than blue. Black-Right-Pointing-Pointer Vibrational cascade free enhanced fluorescence is obtained for the dry sample.

Reduction of titanocene dichloride with dysprosium: access to a stable titanocene(ii) equivalent for phosphite-free Takeda carbonyl olefination.

Science.gov (United States)

Bousrez, G; Déchamps, I; Vasse, J-L; Jaroschik, F

2015-05-28

The reduction of titanocene dichloride with dysprosium yields a new titanocene(ii) equivalent without the need for further stabilising ligands. This reagent can be employed in combination with dithioacetals for the olefination of different carbonyl groups and allows for a simplified all-in-one procedure.

Major conformations of the ligand skeleton of a tetranuclear dysprosium (3) tartrate complex

International Nuclear Information System (INIS)

Chevela, V.V.; Semenov, V.Eh.; Bezryadin, S.G.; Savitskaya, T.V.; Kolesar, I.R.; Matveev, S.N.; Shamov, G.A.

1999-01-01

By the molecular mechanics method (MIND program, stoichiometry was studied and basic conformations of ligand frame of dysprosium (3) tetranuclear complex bis-(d-tartrato) bis-(l-tartrato)tetradysprosiate (3) - anion Dy 4 (d-L) 2 (l-L) 2 4- (1) (d-H 4 L = d-tartaric acid, l-H 4 L = l - tartaric acid) were revealed. It is shown that theoretically calculated mP τ constants for so-called compact conformations of 1, where tartratoligands are in gosh conformation, agree with experimentally obtained constant of paramagnetic birefringence (mP e ) of complex 1 [ru

Nanostructured metal sulfides for energy storage

Science.gov (United States)

Rui, Xianhong; Tan, Huiteng; Yan, Qingyu

2014-08-01

Advanced electrodes with a high energy density at high power are urgently needed for high-performance energy storage devices, including lithium-ion batteries (LIBs) and supercapacitors (SCs), to fulfil the requirements of future electrochemical power sources for applications such as in hybrid electric/plug-in-hybrid (HEV/PHEV) vehicles. Metal sulfides with unique physical and chemical properties, as well as high specific capacity/capacitance, which are typically multiple times higher than that of the carbon/graphite-based materials, are currently studied as promising electrode materials. However, the implementation of these sulfide electrodes in practical applications is hindered by their inferior rate performance and cycling stability. Nanostructures offering the advantages of high surface-to-volume ratios, favourable transport properties, and high freedom for the volume change upon ion insertion/extraction and other reactions, present an opportunity to build next-generation LIBs and SCs. Thus, the development of novel concepts in material research to achieve new nanostructures paves the way for improved electrochemical performance. Herein, we summarize recent advances in nanostructured metal sulfides, such as iron sulfides, copper sulfides, cobalt sulfides, nickel sulfides, manganese sulfides, molybdenum sulfides, tin sulfides, with zero-, one-, two-, and three-dimensional morphologies for LIB and SC applications. In addition, the recently emerged concept of incorporating conductive matrices, especially graphene, with metal sulfide nanomaterials will also be highlighted. Finally, some remarks are made on the challenges and perspectives for the future development of metal sulfide-based LIB and SC devices.

Purification of hydrogen sulfide

International Nuclear Information System (INIS)

Tsao, U.

1978-01-01

A process is described for purifying a hydrogen sulfide gas stream containing carbon dioxide, comprising (a) passing the gas stream through a bed of solid hydrated lime to form calcium hydrosulfide and calcium carbonate and (b) regenerating hydrogen sulfide from said calcium hydrosulfide by reacting the calcium hydrosulfide with additional carbon dioxide. The process is especially applicable for use in a heavy water recovery process wherein deuterium is concentrated from a feed water containing carbon dioxide by absorption and stripping using hydrogen sulfide as a circulating medium, and the hydrogen sulfide absorbs a small quantity of carbon dioxide along with deuterium in each circulation

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...... higher hydrogen sulfide uptake followed by oxidation catalyzed by iron-containing enzymes such as cytochrome c oxidase in a process uncoupled from energy conservation....

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...... higher hydrogen sulfide uptake followed by oxidation catalyzed by iron-containing enzymes such as cytochrome c oxidase in a process uncoupled from energy conservation....

Automated spectrofluorimetric determinations of terbium and dysprosium in rare earth mixtures

Energy Technology Data Exchange (ETDEWEB)

Lyle, S.J.; Za' tar, N. (Kent Univ., Canterbury (UK))

1983-12-01

Several methods involving the use of water-soluble binary and ternary complexes have been proposed for the spectrofluorimetric determination based on terbium(III) emission at 545 nm. These are terbium(III) with (A) ethylenediamine-N,N'-bis(o-hydroxyphenylacetic acid), (B) o-hydroxyphenyliminodiacetic acid, (C) EDTA + 5-sulphosalicylic acid, (D) EDTA + 1,2-dihydroxybenzene-3,5-disulphonic acid disodium salt (Tiron), and (E) iminodiacetic acid (IDA) + Tiron. Two of the reagent mixtures (D and E) can also be used for the fluorimetric determination of dysprosium(III) at 582 nm. A comparison has been made of these methods in order to select the most satisfactory procedure with respect to selectivity, sensitivity and suitability for adaption to automatic operation. Results are given and discussed.

Dysprosium disilicide nanostructures on silicon(001) studied by scanning tunneling microscopy and transmission electron microscopy

International Nuclear Information System (INIS)

Ye Gangfeng; Nogami, Jun; Crimp, Martin A.

2006-01-01

The microstructure of self-assembled dysprosium silicide nanostructures on silicon(001) has been studied by scanning tunneling microscopy and transmission electron microscopy. The studies focused on nanostructures that involve multiple atomic layers of the silicide. Cross-sectional high resolution transmission electron microscopy images and fast Fourier transform analysis showed that both hexagonal and orthorhombic/tetragonal silicide phases were present. Both the magnitude and the anisotropy of lattice mismatch between the silicide and the substrate play roles in the morphology and epitaxial growth of the nanostructures formed

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.

Treatment of rheumatoid synovitis of the knee with intraarticular injection of dysprosium 165-ferric hydroxide macroaggregates

International Nuclear Information System (INIS)

Sledge, C.B.; Zuckerman, J.D.; Zalutsky, M.R.

1986-01-01

One hundred eight knees of 93 patients with seropositive rheumatoid arthritis and persistent synovitis of the knee were treated with an intraarticular injection of 270 mCi of dysprosium 165 bound to ferric hydroxide macroaggregate. Leakage of radioactivity from the injected joint was minimal. Mean leakage to the venous blood 3 hours after injection was 0.11% of the injected dose; this corresponds to a mean whole body dose of 0.2 rads. Mean leakage to the liver 24 hours after injection was 0.64% of the injected dose; this corresponds to a mean liver dose of 3.2 rads. In 7 additional patients examined, there was negligible or near negligible activity found in the draining inguinal lymph nodes. One-year followup was possible for 74 knees (63 patients). Sixty-one percent of the knees had good results, 23% had fair results, and 16% had poor results. There was a direct correlation between the radiographic stage and response to treatment. In knees with stage I radiographic changes, 72% showed good results; 93% showed improvement. In knees with stage II changes, 59% showed good results; 81% showed improvement. These preliminary results indicate that dysprosium 165-ferric hydroxide macroaggregate is an effective agent for radiation synovectomy. The low leakage rates observed offer a definite advantage over agents previously used

Mesostructured metal germanium sulfides

Energy Technology Data Exchange (ETDEWEB)

MacLachlan, M.J.; Coombs, N.; Bedard, R.L.; White, S.; Thompson, L.K.; Ozin, G.A.

1999-12-29

A new class of mesostructured metal germanium sulfide materials has been prepared and characterized. The synthesis, via supramolecular assembly of well-defined germanium sulfide anionic cluster precursors and transition-metal cations in formamide, represents a new strategy for the formation of this class of solids. A variety of techniques were employed to examine the structure and composition of the materials. Structurally, the material is best described as a periodic mesostructured metal sulfide-based coordination framework akin to periodic hexagonal mesoporous silica, MCM-41. At the molecular scale, the materials strongly resemble microstructured metal germanium sulfides, in which the structure of the [Ge{sub 4}S{sub 10}]{sup 4{minus}} cluster building-blocks are intact and linked via {mu}-S-M-S bonds. Evidence for a metal-metal bond in mesostructured Cu/Ge{sub 4}S{sub 10} is also provided.

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...

Sulfidation behavior of Fe20Cr alloys

International Nuclear Information System (INIS)

Pillis, Marina Fuser

2001-01-01

Alloys for use in high temperature environments rely on the formation of an oxide layer for their protection. Normally, these protective oxides are Cr 2 O 3 , Al 2 O 3 and, some times, SiO 2 . Many industrial gaseous environments contain sulfur. Sulfides, formed in the presence of sulfur are thermodynamically less stable, have lower melting points and deviate much more stoichiometrically, compared to the corresponding oxides. The mechanism of sulfidation of various metals is as yet not clear, in spite of the concerted efforts during the last decade. To help address this situation, the sulfidation behavior of Fe20Cr has been studied as a function of compositional modifications and surface state of the alloy. The alloys Fe20Cr, Fe20Cr0.7Y, Fe20Cr5Al and Fe20Cr5Al0.6Y were prepared and three sets of sulfidation tests were carried out. In the first set, the alloys were sulfidized at 700 deg C and 800 deg C for 10h. In the second set, the alloys were pre-oxidized at 1000 deg C and then sulfidized at 800 deg C for up to 45h. In the third set of tests, the initial stages of sulfidation of the alloys was studied. All the tests were carried out in a thermobalance, in flowing H 2 /2%H 2 S, and the sulfidation behavior determined as mass change per unit area. Scanning electron microscopy coupled to energy dispersive spectroscopy and X-ray diffraction analysis were used to characterize the reaction products. The addition of Y and Al increased sulfidation resistance of Fe20Cr. The addition of Y altered the species that diffused predominantly during sulfide growth. It changed from predominant cationic diffusion to predominant anionic diffusion. The addition of Al caused an even greater increase in sulfidation resistance of Fe20Cr, with the parabolic rate constant decreasing by three orders of magnitude. Y addition to the FeCrAl alloy did not cause any appreciable alteration in sulfidation resistance. Pre-oxidation of the FeCrAl and FeCrAlY alloys resulted in an extended

Electrocatalytic approach for the efficiency increase of electrolytic hydrogen production: Proof-of-concept using platinum-dysprosium alloys

International Nuclear Information System (INIS)

Santos, D.M.F.; Šljukić, B.; Sequeira, C.A.C.; Macciò, D.; Saccone, A.; Figueiredo, J.L.

2013-01-01

Development of electrocatalytic materials for the hydrogen evolution reaction (HER) is attempted with the aim of reducing the water electrolysis overpotential and increasing its efficiency. Using linear scan voltammetry measurements of the hydrogen discharge enables evaluation of the electrocatalytic activity for the HER of platinum–dysprosium (Pt–Dy) intermetallic alloy electrodes of different compositions. Understanding of materials electrocatalytic performance is based on determination of several crucial kinetic parameters, including the Tafel coefficients, b, charge transfer coefficients, α, exchange current densities, j 0 , and activation energies, E a . Influence of temperature on HER is investigated by performing studies at temperatures ranging from 25 °C to 85 °C. The effect of the Dy amount in the efficiency of the HER on the Pt–Dy alloys is analysed. Results demonstrate that Dy can substantially increase the electrocatalytic activity of the Pt alloys, in comparison to the single Pt electrode. Efforts are made to correlate the microstructure of the alloys with their performance towards the HER. - Highlights: ► Development of electrocatalysts to increase efficiency of electrolytic hydrogen production. ► Synthesis and evaluation of composition and morphology of platinum–dysprosium (Pt–Dy) alloys. ► Hydrogen evolution reaction on Pt–Dy alloys electrodes studied using linear scan voltammetry in alkaline medium. ► Pt–Dy alloy with equiatomic composition enhances kinetics of hydrogen discharge compared to single Pt

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...... 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...... not present in terrestrial plants at that level. Sulfide is not necessarily toxic but used as sulfur nutrition, presupposing healthy seagrass ecosystems that can support detoxification mechanisms. Presence or absence of those mechanisms determines susceptibility of seagrass ecosystems to sediment sulfide...

Electrochemical behaviour of dysprosium in the eutectic LiCl-KCl at W and Al electrodes

International Nuclear Information System (INIS)

Castrillejo, Y.; Bermejo, M.R.; Barrado, A.I.; Pardo, R.; Barrado, E.; Martinez, A.M.

2005-01-01

The electrochemical behaviour of DyCl 3 was studied in the eutectic LiCl-KCl at different temperatures. The cathodic reaction can be written:Dy(III)+3e-bar Dy(0)which can be divided in two very close cathodic steps:Dy(III)+1e-bar Dy(II)andDy(II)+2e-bar Dy(0)Transient electrochemical techniques, such as cyclic voltammetry, chronopotentiometry, and chronoamperometry were used in order to study the reaction mechanism and the transport parameters of electroactive species at a tungsten electrode. The results showed that in the eutectic LiCl-KCl, electrocrystallization of dysprosium seems to be the controlling electrochemical step. Chronoamperometric studies indicated instantaneous nucleation of dysprosium with three dimensional growth of the nuclei whatever the applied overpotential.Mass transport towards the electrode is a simple diffusion process, and the diffusion coefficient of the electroactive species, i.e. Dy(III), has been calculated. The validity of the Arrhenius law was also verified by plotting the variation of the logarithm of the diffusion coefficient versus 1/T.In addition, the electrode reactions of the LiCl-KCl-DyCl 3 solutions at an Al wire were also investigated by cyclic voltammetry and open circuit chronopotentiometry. The redox potential of the Dy(III)/Dy couple at the Al electrode was observed at more positive potentials values than those at the inert electrode. This potential shift was thermodynamically analyzed by a lowering of activity of Dy in the metal phase due to the formation of intermetallic compounds

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 in...

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 in...

Carbon steel protection in G.S. (Girlder sulfide) plants. Iron sulfide scales formation conditions. Pt. 1

International Nuclear Information System (INIS)

Bruzzoni, P.; Burkart, A.L.; Garavaglia, R.N.

1981-11-01

An ASTM A 516 degree 60 carbon steel superficial protection technique submitted to a hydrogen-water sulfide corrosive medium at 2 MPa of pressure and 40-125 deg C forming on itself an iron sulfide layer was tested. Studies on pH influence, temperature, passivating mean characteristics and exposure time as well as the mechanical resistance of sulfide layers to erosion are included. (Author) [es

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 H2S...

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....

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...... such simulations have potential for further improving odor and sulfide management. The campaign covered measurement of wastewater sulfide by grab sampling and diurnal sampling, and H2S gas in the sewer atmosphere was logged. The tested model was based on the Wastewater Aerobic/Anaerobic Transformations in Sewers...... (WATS) sewer process concept, which never had been calibrated to such an extensive dataset. The study showed that the model was capable of reproducing the general levels of wastewater sulfide, wastewater pH, and sewer H2S gas. It could also reproduce the general variability of these parameters, albeit...

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....

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

A model for additive transport in metal halide lamps containing mercury and dysprosium tri-iodide

International Nuclear Information System (INIS)

Beks, M L; Haverlag, M; Mullen, J J A M van der

2008-01-01

The distribution of additives in a metal halide lamp is examined through numerical modelling. A model for a lamp containing sodium iodide additives has been modified to study a discharge containing dysprosium tri-iodide salts. To study the complex chemistry the method of Gibbs minimization is used to decide which species have to be taken into account and to fill lookup tables with the chemical composition at different combinations of elemental abundance, lamp pressure and temperature. The results from the model with dysprosium additives were compared with earlier results from the lamp containing sodium additives and a simulation of a pure mercury lamp. It was found that radial segregation creates the conditions required for axial segregation. Radial segregation occurs due to the unequal diffusion of atoms and molecules. Under the right conditions convection currents in the lamp can cause axial demixing. These conditions depend on the ratio of axial convection and radial diffusion as expressed by the Peclet number. At a Peclet number of unity axial segregation is most pronounced. At low Peclet numbers radial segregation is at its worst, while axial segregation is not present. At large Peclet numbers the discharge becomes homogeneously mixed. The degree of axial segregation at a Peclet number of unity depends on the temperature at which the additive under consideration fully dissociates. If the molecules dissociate very close to the walls no molecules are transported by the convective currents in the lamp, and hence axial segregation is limited. If they dissociate further away from the walls in the area where the downward convective currents are strongest, more axial segregation is observed

Electron transfer to sulfides:

International Nuclear Information System (INIS)

Meneses, Ana Belen; Antonello, Sabrina; Arevalo, Maria Carmen; Maran, Flavio

2005-01-01

The problem of characterizing the steps associated with the dissociative reduction of sulfides has been addressed. The electrochemical reduction of diphenylmethyl para-methoxyphenyl sulfide in N,N-dimethylformamide, on both glassy carbon and mercury electrodes, was chosen as a test system. The electrode process involves the slow heterogeneous outer-sphere electron transfer to the sulfide, the fast cleavage of the C-S bond, the reduction of the ensuing carbon radical, and the self-protonation triggered by the generation of the strong base Ph 2 CH - . The latter reaction is rather slow, in agreement with the large intrinsic barriers characterizing proton transfers between CH-acids and carbon bases. The dissociative reduction was studied in the presence of an exogenous acid. The results, obtained by convolution analysis, point to a stepwise DET mechanism in which the ET step is accompanied by rather large reorganization energy. Similar results were obtained on both electrode materials. Analysis of the heterogeneous electron transfer and associated C-S bond cleavage indicate that the reduction of this and other sulfides lies between the stepwise dissociative electron transfers leading to the formation of stiff π* radical anions and those going through the intermediacy of loose σ* radical anions

Dysprosium lithium borate glass mircrospheres for radiation synovectomy: The in vitro and in vivo performance evaluation

Energy Technology Data Exchange (ETDEWEB)

Zhao Di; Yu Jing [Institute of Bioengineering and Information Technology Materials, Center for Advanced Materials and Nano-Biomedicine, Tongji University, Shanghai, 200092 (China); Huang Wenhai, E-mail: whhuang@tongji.edu.cn [Institute of Bioengineering and Information Technology Materials, Center for Advanced Materials and Nano-Biomedicine, Tongji University, Shanghai, 200092 (China); Zhou Nai; Wang Deping [Institute of Bioengineering and Information Technology Materials, Center for Advanced Materials and Nano-Biomedicine, Tongji University, Shanghai, 200092 (China); Yin Wei [Institute of Isotope Research, Sinitic Academy of Atomic Energy, Beijing 102413 (China); Chen Yaqing [The Sixth People' s Hospital, Shanghai 200233 (China)

2010-08-30

The radioactive dysprosium lithium borate glass (DyLB) microspheres with different glass compositions were prepared for radiation synovectomy. The biodegradability and biocompatibility of these DyLB microspheres were evaluated in vitro and in vivo. The DyLB microspheres studied in this work were partially biodegradable in a simulated body fluid (SBF), with the final weight loss of the microspheres in the range of 24.6% and 55.0% (wt.%) after 8 days of immersion. The ICP results revealed that the dissolution of lithium significantly decreased from 100% to 53.7% with increasing content of Dy{sub 2}O{sub 3} in the microspheres from 18% to 22% (wt.%, from S-1 to S-3). However, for all of the three samples, nearly all of the dysprosium (> 99.997%, wt.%) remained in the microspheres, in the form of insoluble phosphates and carbonates, which was proved by the SEM and EDX analyses. The degradation of DyLB microspheres in SBF gradually decreased with immersion time and eventually reached equilibrium after 7 days of immersion. Compared to the other two samples, the S-3 sample with the lowest Dy{sup 3+} dissolution (about 0.002%) was considered more secure for clinical application. Furthermore, the S-3 DyLB microspheres exhibited good biocompatibility, since neither tissue damage nor inflammation was observed, after they were implanted in the liver of rat for two weeks. After neutron activation, the radionuclide purity of radioactive S-3 DyLB microspheres was 99.999%, which were suitable for radiation synovectomy.

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

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

Custom Coordination Environments for Lanthanoids: Tripodal Ligands Achieve Near-Perfect Octahedral Coordination for Two Dysprosium-Based Molecular Nanomagnets.

Science.gov (United States)

Lim, Kwang Soo; Baldoví, José J; Jiang, ShangDa; Koo, Bong Ho; Kang, Dong Won; Lee, Woo Ram; Koh, Eui Kwan; Gaita-Ariño, Alejandro; Coronado, Eugenio; Slota, Michael; Bogani, Lapo; Hong, Chang Seop

2017-05-01

Controlling the coordination sphere of lanthanoid complexes is a challenging critical step toward controlling their relaxation properties. Here we present the synthesis of hexacoordinated dysprosium single-molecule magnets, where tripodal ligands achieve a near-perfect octahedral coordination. We perform a complete experimental and theoretical investigation of their magnetic properties, including a full single-crystal magnetic anisotropy analysis. The combination of electrostatic and crystal-field computational tools (SIMPRE and CONDON codes) allows us to explain the static behavior of these systems in detail.

Kinetics of the nitridation of dysprosium during mechanochemical processing

Energy Technology Data Exchange (ETDEWEB)

Alanko, Gordon A.; Osterberg, Daniel D.; Jaques, Brian J. [Department of Materials Science and Engineering, College of Engineering, Boise State University, 1910 University Drive, Boise, ID 83725 (United States); Hurley, Michael F. [Department of Materials Science and Engineering, College of Engineering, Boise State University, 1910 University Drive, Boise, ID 83725 (United States); Center for Advanced Energy Studies, 995 University Boulevard, Idaho Falls, ID 83401 (United States); Butt, Darryl P., E-mail: darrylbutt@boisestate.edu [Department of Materials Science and Engineering, College of Engineering, Boise State University, 1910 University Drive, Boise, ID 83725 (United States); Center for Advanced Energy Studies, 995 University Boulevard, Idaho Falls, ID 83401 (United States)

2015-01-25

Highlights: • DyN was mechanochemically synthesized by milling pure metal under nitrogen. • Temperature and pressure were monitored to investigate reaction progress. • The effects of metal adhered to media on the impact energetics was measured. • The reactive milling kinetics are described in terms of reactive surface formation. - Abstract: Dysprosium nitride was synthesized by the reactive milling of the rare earth metal under 400 kPa nitrogen gas in a planetary ball mill. The nitrogen consumption rate was calculated from in situ temperature and pressure measurements to find the reaction extent as a function of milling time at milling speeds from 350 to 650 rpm. The results are analyzed in terms of a fundamental milling dynamics model in which the input milling energy is the primary driving force for reaction and the rate limiting step of the nitridation kinetics is the formation of chemically active surfaces. The model differs from traditional gas–solid reactions which are often limited by diffusion of a species through a surface layer or by dissociation of the gas molecule. These results give fresh insight into reactive gas–solid milling kinetics.

Self-organized dysprosium-directed alginate hydrogels and its chemical features

Energy Technology Data Exchange (ETDEWEB)

Ma, Qianmin [School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Gao, Jinwei [Institute for Advanced Materials, Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006 (China); Peng, Huojun [School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Wang, Qianming, E-mail: qmwang@scnu.edu.cn [Key Laboratory of Theoretical Chemistry of Environment, Ministry of Education, School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Guangzhou Key Laboratory of Materials for Energy Conversion and Storage, Guangzhou 510006 (China)

2016-09-15

Rational use of self-organized materials may contribute in developing new structures and devices in practical technology. Synthetic metallo-supramolecular gels are generally designed with transitional metal-directed process. However, the assembly of both lanthanide and sodium alginate in macromolecular systems would find a new way of utilizing its physical properties. The stimuli-responsive molecule (alginate) could firmly form stable hydrogels upon the encapsulation of dysprosium ions. In addition, the immobilization of YVO{sub 4}: Eu{sup 3+} nanoparticle in the soft matrix has been achieved and it has never been explored in the fabrication of phosphor-incorporated luminescent alginate gels. The key feature of the present soft matter is that its red emission could be switched off in the presence of sodium ascorbate and the results may have a tremendous impact on the extension of photophysical application based on soft nanoscale devices. - Highlights: • Dy{sup 3+} can be used for the gelation of the dissolved alginate. • Lanthanide hydrogels could exhibit red emissions under excitations. • Luminescence could be switched “off” in the presence of sodium ascorbate.

Technetium behavior in sulfide and ferrous iron solutions

International Nuclear Information System (INIS)

Lee, S.Y.; Bondietti, E.A.

1982-01-01

Pertechnetate oxyanion ( 99 TcO 4- ), a potentially mobile species in leachate from a breached radioactive waste repository, was removed from a brine solution by precipitation with sulfide, iron, and ferrous sulfide at environmental pH's. Maghemite (ν-Fe 2 O 3 ) and geothite (α-FeOOH) were the dominant minerals in the precipitate obtained from the TcO 4- -ferrous iron reaction. The observation of small particle size and poor crystallinity of the minerals formed in the presence of Tc suggested that the Tc was incorporated into the mineral structure after reduction to a lower valence state. Amorphous ferrous sulfide, an initial phase precipitating in the TcO 4- -ferrous iron-sulfide reaction, was transformed to goethite and hematite (α-Fe 2 O 3 ) on aging. The black precipitate obtained from the TcO 4- -sulfide reaction was poorly crystallized technetium sulfide (Tc 2 S 7 ) which was insoluble in both acid and alkaline solution in the absence of strong oxidents. The results suggested that ferrous- and/or sulfide-bearing groundwaters and minerals in host rocks or backfill barriers could reduce the mobility of Tc through the formation of less-soluble Tc-bearing iron and/or sulfide minerals

Evaluating United States and world consumption of neodymium, dysprosium, terbium, and praseodymium in final products

Science.gov (United States)

Hart, Matthew

This paper develops scenarios of future rare-earth-magnet metal (neodymium, dysprosium, terbium, and praseodymium) consumption in the permanent magnets used in wind turbines and hybrid electric vehicles. The scenarios start with naive base-case scenarios for growth in wind-turbine and hybrid-electric-vehicle sales over the period 2011 to 2020, using historical data for each good. These naive scenarios assume that future growth follows time trends in historical data and does not depend on any exogenous variable. Specifically, growth of each technological market follows historical time trends, and the amount of rare earths used per unit of technology remains fixed. The chosen reference year is 2010. Implied consumptions of the rare earth magnet metals are calculated from these scenarios. Assumptions are made for the material composition of permanent magnets, the market share of permanent-magnet wind turbines and vehicles, and magnet weight per unit of technology. Different scenarios estimate how changes in factors like the material composition of magnets, growth of the economy, and the price of a substitute could affect future consumption. Each scenario presents a different method for reducing rare earth consumption and could be interpreted as potential policy choices. In 2010, the consumption (metric tons, rare-earth-oxide equivalent) of each rare-earth-magnet metal was as follows. Total neodymium consumption in the world for both technologies was 995 tons; dysprosium consumption was 133 tons; terbium consumption was 50 tons; praseodymium consumption was zero tons. The base scenario for wind turbines shows there could be strong, exponential growth in the global wind turbine market. New U.S. sales of hybrid vehicles would decline (in line with the current economic recession) while non-U.S. sales increase through 2020. There would be an overall increase in the total amount of magnetic rare earths consumed in the world. Total consumption of each rare earth in the short

Watt-level dysprosium fiber laser at 315 μm with 73% slope efficiency

Science.gov (United States)

Woodward, R. I.; Majewski, M. R.; Bharathan, G.; Hudson, D. D.; Fuerbach, A.; Jackson, S. D.

2018-04-01

Rare-earth-doped fiber lasers are emerging as promising high-power mid-infrared sources for the 2.6-3.0 {\\mu}m and 3.3-3.8 {\\mu}m regions based on erbium and holmium ions. The intermediate wavelength range, however, remains vastly underserved, despite prospects for important manufacturing and defense applications. Here, we demonstrate the potential of dysprosium-doped fiber to solve this problem, with a simple in-band pumped grating-stabilized linear cavity generating up to 1.06 W at 3.15 {\\mu}m. A slope efficiency of 73% with respect to launched power (77% relative to absorbed power) is achieved: the highest value for any mid-infrared fiber laser to date, to the best of our knowledge. Opportunities for further power and efficiency scaling are also discussed.

Carbon steel protection in G.S. (Girlder sulfide) plants. Pressure influence on iron sulfide scales formation. Pt. 5

International Nuclear Information System (INIS)

Delfino, C.A.; Lires, O.A.; Rojo, E.A.

1987-01-01

In order to protect carbon steel towers and piping of Girlder sulfide (G.S.) experimental heavy water plants against corrosion produced by the action of aqueous solutions of hydrogen sulfide, a method, previously published, was developed. Carbon steel, exposed to saturated aqueous solutions of hydrogen sulfide, forms iron sulfide scales. In oxygen free solutions evolution of corrosion follows the sequence: mackinawite → cubic ferrous sulfide → troilite → pyrrotite → pyrite. Scales formed by pyrrotite-pyrite or pyrite are the most protective layers (these are obtained at 130 deg C, 2MPa, for periods of 14 days). Experiments, at 125 deg C and periods of 10-25 days, were performed in two different ways: 1- constant pressure operations at 0.5 and 1.1 MPa. 2- variable pressure operation between 0.3-1 MPa. In all cases pyrrotite-pyrite scales were obtained. (Author) [es

Experimental simulations of sulfide formation in the solar nebula.

Science.gov (United States)

Lauretta, D S; Lodders, K; Fegley, B

1997-07-18

Sulfurization of meteoritic metal in H2S-H2 gas produced three different sulfides: monosulfide solid solution [(Fe,Ni)1-xS], pentlandite [(Fe,Ni)9-xS8], and a phosphorus-rich sulfide. The composition of the remnant metal was unchanged. These results are contrary to theoretical predictions that sulfide formation in the solar nebula produced troilite (FeS) and enriched the remaining metal in nickel. The experimental sulfides are chemically and morphologically similar to sulfide grains in the matrix of the Alais (class CI) carbonaceous chondrite, suggesting that these meteoritic sulfides may be condensates from the solar nebula.

The study of heat conductivity properties of GdS1.48 and DyS1.48

International Nuclear Information System (INIS)

Ahmadov, O.R.

2009-01-01

The heat conductivity properties of sulfides of gadolinium and dysprosium up to 900 K with use of the average speed of ultrasound distribution, a specific thermal capacity and Viderman-Frans law have been investigated. The value of Debay temperature, thermal extension coefficient and the temperature dependence are established. It is shown that the scattering on crystal lattice phonons plays the main role in lattice heat conductivity

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

Influence of modifiers on the separation of dysprosium from neodymium using organophosphorus acid derivates

Energy Technology Data Exchange (ETDEWEB)

Elwert, Tobias; Schwarz, Sabrina; Goldmann, Daniel [TU Clausthal, Clausthal-Zellerfeld (Germany). Lehrstuhl fuer Rohstoffaufbereitung und Recycling

2016-01-15

The aim of this study was to investigate the applicability of three organophosphorus acid derivates (D2EHPA, EHEHPA and Cyanex 572) for the separation of terbium and dysprosium from praseodymium and neodymium from NdFeB magnets in chloride solution. A special focus was put on the effect of phase modifiers. The investigations revealed that all extractants show in general a similar extraction behavior but the extraction is shifted to higher pH values in the order D2EHPA < EHEHPA < Cyanex 572. Therefore, and due to higher realizable loadings, EHEHPA and Cyanex 572 are more suitable for the investigated separation problem than D2EHPA. Whereas EHEHPA requires 1-decanol as phase modifier, Cyanex 572 can be employed without modifier addition.

Spectrographic determination of dysprosium in doped crystals of calcium sulfate used for dosimetric material

International Nuclear Information System (INIS)

Grigoletto, T.; Lordello, A.R.

1984-01-01

A spectrographic method is described for the quantitative determination of dysprosium in doped crystals of calcium sulphate. The consequences of the changes in some parameters of the excitation conditions, such as arc current, electrode type and total or partial burning of sample, in the analytical results are discussed. Matrix effects are investigated. Variations in the intensity of the spectral lines are verified by recording the spectrum in distinct photographic plates. The role of internal standard in analytical reproducibility and in counterbalance of the variations in the arc current and in the weight of sample is studied. Accuracy is estimated by comparative analysis of two calcium sulphate samples by X-Ray Fluorescence, Neutron Activation and Inductive Coupled Plasma Emission Spectroscopy. (M.A.C.) [pt

Adsorption of sulfide ions on cerussite surfaces and implications for flotation

International Nuclear Information System (INIS)

Feng, Qicheng; Wen, Shuming; Zhao, Wenjuan; Deng, Jiushuai; Xian, Yongjun

2016-01-01

Highlights: • A new discussion on the lead sulfide species is introduced. • The Na_2S concentration determines cerussite sulfidization. • The activity of lead sulfide species also determines cerussite sulfidization. • Disulfide and polysulfide in lead sulfide species affect its activity. - Abstract: The adsorption of sulfide ions on cerussite surfaces and implications for flotation were studied by X-ray photoelectron spectroscopy (XPS) analysis, micro-flotation tests, and surface adsorption experiments. The XPS analysis results indicated that lead sulfide species formed on the mineral surface after treatment by Na_2S, and the increase in the Na_2S concentration was beneficial for sulfidization. In addition to the content of lead sulfide species, its activity, which was determined by the proportion of sulfide, disulfide and polysulfide, also played an important role in cerussite sulfidization. Micro-flotation tests results demonstrated that insufficient or excessive addition of Na_2S in pulp solutions has detrimental effects on flotation performance, which was attributed to the dosage of Na_2S and the activity of lead sulfide species formed on the mineral surface. Surface adsorption experiments of sulfide ions determined the residual S concentrations in pulp solutions and provided a quantitative illustration for the inhibition of cerussite flotation by excessive sulfide ions. Moreover, it also revealed that sulfide ions in the pulp solution were transformed onto the mineral surface and formed lead sulfide species. These results showed that both of lead sulfide species and its activity acted as an important role in sulfidization flotation process of cerussite.

Adsorption of sulfide ions on cerussite surfaces and implications for flotation

Energy Technology Data Exchange (ETDEWEB)

Feng, Qicheng [State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Kunming University of Science and Technology, Kunming 650093 (China); Faculty of Land Resource Engineering, Kunming University of Science and Technology, Kunming 650093 (China); Wen, Shuming, E-mail: fqckmust@126.com [State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Kunming University of Science and Technology, Kunming 650093 (China); Faculty of Land Resource Engineering, Kunming University of Science and Technology, Kunming 650093 (China); Zhao, Wenjuan [Kunming Metallurgical Research Institute, Kunming 650031 (China); Deng, Jiushuai; Xian, Yongjun [State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Kunming University of Science and Technology, Kunming 650093 (China); Faculty of Land Resource Engineering, Kunming University of Science and Technology, Kunming 650093 (China)

2016-01-01

Highlights: • A new discussion on the lead sulfide species is introduced. • The Na{sub 2}S concentration determines cerussite sulfidization. • The activity of lead sulfide species also determines cerussite sulfidization. • Disulfide and polysulfide in lead sulfide species affect its activity. - Abstract: The adsorption of sulfide ions on cerussite surfaces and implications for flotation were studied by X-ray photoelectron spectroscopy (XPS) analysis, micro-flotation tests, and surface adsorption experiments. The XPS analysis results indicated that lead sulfide species formed on the mineral surface after treatment by Na{sub 2}S, and the increase in the Na{sub 2}S concentration was beneficial for sulfidization. In addition to the content of lead sulfide species, its activity, which was determined by the proportion of sulfide, disulfide and polysulfide, also played an important role in cerussite sulfidization. Micro-flotation tests results demonstrated that insufficient or excessive addition of Na{sub 2}S in pulp solutions has detrimental effects on flotation performance, which was attributed to the dosage of Na{sub 2}S and the activity of lead sulfide species formed on the mineral surface. Surface adsorption experiments of sulfide ions determined the residual S concentrations in pulp solutions and provided a quantitative illustration for the inhibition of cerussite flotation by excessive sulfide ions. Moreover, it also revealed that sulfide ions in the pulp solution were transformed onto the mineral surface and formed lead sulfide species. These results showed that both of lead sulfide species and its activity acted as an important role in sulfidization flotation process of cerussite.

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

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. Copyright © 2014 Elsevier Ltd. All rights reserved.

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.

Sulfide Precipitation in Wastewater at Short Timescales

DEFF Research Database (Denmark)

Kiilerich, Bruno; van de Ven, Wilbert; Nielsen, Asbjørn Haaning

2017-01-01

Abatement of sulfides in sewer systems using iron salts is a widely used strategy. When dosing at the end of a pumping main, the reaction kinetics of sulfide precipitation becomes important. Traditionally the reaction has been assumed to be rapid or even instantaneous. This work shows that this i......Abatement of sulfides in sewer systems using iron salts is a widely used strategy. When dosing at the end of a pumping main, the reaction kinetics of sulfide precipitation becomes important. Traditionally the reaction has been assumed to be rapid or even instantaneous. This work shows...... that this is not the case for sulfide precipitation by ferric iron. Instead, the reaction time was found to be on a timescale where it must be considered when performing end-of-pipe treatment. For real wastewaters at pH 7, a stoichiometric ratio around 14 mol Fe(II) (mol S(−II))−1 was obtained after 1.5 s, while the ratio...

Low Field Magnetic and Thermal Hysteresis in Antiferromagnetic Dysprosium

Directory of Open Access Journals (Sweden)

Iuliia Liubimova

2017-06-01

Full Text Available Magnetic and thermal hysteresis (difference in magnetic properties on cooling and heating have been studied in polycrystalline Dy (dysprosium between 80 and 250 K using measurements of the reversible Villari effect and alternating current (AC susceptibility. We argue that measurement of the reversible Villari effect in the antiferromagnetic phase is a more sensitive method to detect magnetic hysteresis than the registration of conventional B(H loops. We found that the Villari point, recently reported in the antiferromagnetic phase of Dy at 166 K, controls the essential features of magnetic hysteresis and AC susceptibility on heating from the ferromagnetic state: (i thermal hysteresis in AC susceptibility and in the reversible Villari effect disappears abruptly at the temperature of the Villari point; (ii the imaginary part of AC susceptibility is strongly frequency dependent, but only up to the temperature of the Villari point; (iii the imaginary part of the susceptibility drops sharply also at the Villari point. We attribute these effects observed at the Villari point to the disappearance of the residual ferromagnetic phase. The strong influence of the Villari point on several magnetic properties allows this temperature to be ranked almost as important as the Curie and Néel temperatures in Dy and likely also for other rare earth elements and their alloys.

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...

The liquid membrane for extraction of Yttrium and Dysprosium from Acid Nitric

International Nuclear Information System (INIS)

Johny, W.S.; Raldi-Artono-Koestoer; Kris-Tri-Basuki; Sudibyo

1996-01-01

The determination of surfactant in liquid membrane has been done. The surfactant is span-80 (sorbitol-monooleate), the liquid membrane phase was the organic phase (O), the internal liquid phase (W) with ratio O/W = 1, and surfactant. The organic phase using D 2 EHPA in the kerosene and the internal liquid phase using aqua des or acid nitric. The determination of surfactant with variation of span-80 (0,25 - 2%) in the liquid membrane volume. The speed of stirrer was 3500 rpm in 20 minute. The ratio of liquid membrane phase form and external phase (aqua des or acid nitric) was 1, the speed of stirrer was 350 rpm in 10 minute (permeation process). The liquid phase and the liquid membrane phase was separated and then determinated the volume of liquid membrane, the result of percentage of span-80 was 0,25 % volume. The extraction of yttrium and dysprosium in 2 M HNO 3 was Kd y = 2.945 and Kd D y = 0.019

Sulfide-conducting solid electrolytes

International Nuclear Information System (INIS)

Kalinina, L.A.; Shirokova, G.I.; Murin, I.V.; Ushakova, Yu.N.; Fominykh, E.G.; Lyalina, M.Yu.

2000-01-01

Feasibility of sulfide transfer in phases on the basis of BaZrS 3 and MLn 2 S 4 ( M = Ca, Ba; Ln = La, Y, Tm, Nd, Sm, Pr) is considered. Solid solution regions on the basis of ternary compounds are determined. Systematic study of the phases is carried out making use of the methods of conductometry, emf in chemical concentration chains without/with transfer, potentiostatic chronoamperometry. Possible mechanism of defect formation during successive alloying of ternary sulfides by binary ones in suggested [ru

Anoxic sulfide biooxidation using nitrite as electron acceptor

International Nuclear Information System (INIS)

Mahmood, Qaisar; Zheng Ping; Cai Jing; Wu Donglei; Hu, Baolan; Li Jinye

2007-01-01

Biotechnology can be used to assess the well being of ecosystems, transform pollutants into benign substances, generate biodegradable materials from renewable sources, and develop environmentally safe manufacturing and disposal processes. Simultaneous elimination of sulfide and nitrite from synthetic wastewaters was investigated using a bioreactor. A laboratory scale anoxic sulfide-oxidizing (ASO) reactor was operated for 135 days to evaluate the potential for volumetric loading rates, effect of hydraulic retention time (HRT) and substrate concentration on the process performance. The maximal sulfide and nitrite removal rates were achieved to be 13.82 and 16.311 kg/(m 3 day), respectively, at 0.10 day HRT. The process can endure high sulfide concentrations, as the sulfide removal percentage always remained higher than 88.97% with influent concentration up to 1920 mg/L. Incomplete sulfide oxidation took place due to lower consumed nitrite to sulfide ratios of 0.93. It also tolerated high nitrite concentration up to 2265.25 mg/L. The potential achieved by decreasing HRT at fixed substrate concentration is higher than that by increasing substrate concentration at fixed HRT. The process can bear short HRT of 0.10 day but careful operation is needed. Nitrite conversion was more sensitive to HRT than sulfide conversion when HRT was decreased from 1.50 to 0.08 day. Stoichiometric analyses and results of batch experiments show that major part of sulfide (89-90%) was reduced by nitrite while some autooxidation (10-11%) was resulted from presence of small quantities of dissolved oxygen in the influent wastewater. There was ammonia amassing in considerably high amounts in the bioreactor when the influent nitrite concentration reached above 2265.25 mg/L. High ammonia concentrations (200-550 mg/L) in the bioreactor contributed towards the overall inhibition of the process. Present biotechnology exhibits practical value with a high potential for simultaneous removal of nitrite

Oxidation and Precipitation of Sulfide in Sewer Networks

DEFF Research Database (Denmark)

Nielsen, A. H.

risks and corrosion of concrete and metals. Most of the problems relate to the buildup of hydrogen sulfide in the atmosphere of sewer networks. In this respect, the processes of the sulfur cycle are of fundamental importance in ultimately determining the extent of such problems. This study focused...... calibrated and validated against field data. In the extension to the WATS model, sulfur transformations were described by six processes: 1. Sulfide production taking place in the biofilm and sediments covering the permanently wetted sewer walls; 2. Biological sulfide oxidation in the permanently wetted...... to the sewer atmosphere, potentially resulting in concrete corrosion. The extended WATS model represents a major improvement over previously developed models for prediction of sulfide buildup in sewer networks. Compared to such models, the major processes governing sulfide buildup in sewer networks...

Kinetic Spectrophotometric Determination of Trace Amounts of Sulfide

Energy Technology Data Exchange (ETDEWEB)

Barzegar, Mohsen [Tarbiat Modarres University, Tehran (Iran, Islamic Republic of); Jabbari, Ali [K. N. Toosi University, Tehran (Iran, Islamic Republic of); Esmaeili, Majid [Razi University, Kermanshah (Iran, Islamic Republic of)

2003-09-15

A method for the determination of trace amount of sulfide based on the addition reaction of sulfide with methyl green at pH 7.5 and 25 .deg. C is described. The reaction is monitored spectrophotometrically by measuring the decrease in absorbance of the dyestuff at 637 nm by the initial rate and fixed time method. The calibration graph is linear in the range 30-1200 ppb. The theoretical limit of detection was 0.014 ppm. Seven replicate analysis of a sample solution containing 0.70 ppm sulfide gave a relative standard deviation of 1.5%. The interfering effects of various ions on sulfide determination have been reported and procedures for removal of interference have been described. The proposed method was applied successfully to the determination of sulfide in tap and wastewater samples.

Kinetic Spectrophotometric Determination of Trace Amounts of Sulfide

International Nuclear Information System (INIS)

Barzegar, Mohsen; Jabbari, Ali; Esmaeili, Majid

2003-01-01

A method for the determination of trace amount of sulfide based on the addition reaction of sulfide with methyl green at pH 7.5 and 25 .deg. C is described. The reaction is monitored spectrophotometrically by measuring the decrease in absorbance of the dyestuff at 637 nm by the initial rate and fixed time method. The calibration graph is linear in the range 30-1200 ppb. The theoretical limit of detection was 0.014 ppm. Seven replicate analysis of a sample solution containing 0.70 ppm sulfide gave a relative standard deviation of 1.5%. The interfering effects of various ions on sulfide determination have been reported and procedures for removal of interference have been described. The proposed method was applied successfully to the determination of sulfide in tap and wastewater samples

LIGNOCELLULOSE NANOCOMPOSITE CONTAINING COPPER SULFIDE

OpenAIRE

Sanchi Nenkova; Peter Velev; Mirela Dragnevska; Diyana Nikolova; Kiril Dimitrov

2011-01-01

Copper sulfide-containing lignocellulose nanocomposites with improved electroconductivity were obtained. Two methods for preparing the copper sulfide lignocellulose nanocomposites were developed. An optimization of the parameters for obtaining of the nanocomposites with respect to obtaining improved electroconductivity, economy, and lower quantities and concentration of copper and sulfur ions in waste waters was conducted. The mechanisms and schemes of delaying and subsequent connection of co...

Catalytic oxidation of sulfide in drinking water treatment: activated carbon as catalyst; Katalytische Oxidation von Sulfid bei der Trinkwasseraufbereitung: Aktivkohle als Katalysator

Energy Technology Data Exchange (ETDEWEB)

Hultsch, V; Grischek, T; Wolff, D; Worch, E [Technische Univ. Dresden (Germany). Inst. fuer Wasserchemie; Gun, J [Hebrew Univ. of Jerusalem (Israel). Div. of Environmental Sciences, Fredy and Nadine Herrmann School of Applied Science

2001-07-01

In regions with warm climate and limited water resources high sulfide concentrations in groundwater can cause problems during drinking water treatment. Aeration of the raw water is not always sufficient to ensure the hydrogen sulfide concentration below the odour threshold value for hydrogen sulfide. As an alternative, activated carbon can be used as a catalyst for sulfide oxidation of raw water. The use of different types of activated carbon was investigated in kinetic experiments. Both Catalytic Carbon from Calgon Carbon and granulated activated carbon from Norit showed high catalytic activities. The results of the experiments are discussed with regard to the practical use of activated carbon for the elimination of hydrogen sulfide during drinking water treatment. (orig.)

A Reaction Involving Oxygen and Metal Sulfides.

Science.gov (United States)

Hill, William D. Jr.

1986-01-01

Describes a procedure for oxygen generation by thermal decomposition of potassium chlorate in presence of manganese dioxide, reacted with various sulfides. Provides a table of sample product yields for various sulfides. (JM)

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.

Simultaneous removal of sulfide, nitrate and acetate: Kinetic modeling

Energy Technology Data Exchange (ETDEWEB)

Wang Aijie, E-mail: waj0578@hit.edu.cn [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology (SKLUWRE, HIT), Harbin 150090 (China); Liu Chunshuang; Ren Nanqi; Han Hongjun [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology (SKLUWRE, HIT), Harbin 150090 (China); Lee Duujong [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology (SKLUWRE, HIT), Harbin 150090 (China); Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan (China)

2010-06-15

Biological removal of sulfide, nitrate and chemical oxygen demand (COD) simultaneously from industrial wastewaters to elementary sulfur (S{sup 0}), N{sub 2}, and CO{sub 2}, or named the denitrifying sulfide (DSR) process, is a cost effective and environmentally friendly treatment process for high strength sulfide and nitrate laden organic wastewater. Kinetic model for the DSR process was established for the first time on the basis of Activated Sludge Model No. 1 (ASM1). The DSR experiments were conducted at influent sulfide concentrations of 200-800 mg/L, whose results calibrate the model parameters. The model correlates well with the DSR process dynamics. By introducing the switch function and the inhibition function, the competition between autotrophic and heterotrophic denitrifiers is quantitatively described and the degree of inhibition of sulfide on heterotrophic denitrifiers is realized. The model output indicates that the DSR reactor can work well at 0.5 < C/S < 3.0 with influent sulfide concentration of 400-1000 mg/L. At >1000 mg/L influent sulfide, however, the DSR system will break down.

Design and validation of a photon insensitive multidetector neutron spectrometer based on Dysprosium activation foils

International Nuclear Information System (INIS)

Gómez-Ros, J.M.; Bedogni, R.; Palermo, I.; Esposito, A.; Delgado, A.; Angelone, M.; Pillon, M.

2011-01-01

This communication describes a photon insensitive passive neutron spectrometer consisting of Dysprosium (Dy) activation foils located along three perpendicular axes within a single moderating polyethylene sphere. The Monte Carlo code MCNPX 2.6 was used to optimize the spatial arrangement of the detectors and to derive the spectrometer response matrix. Nearly isotropic response in terms of neutron fluence for energies up to 20 MeV was obtained by combining the readings of the detectors located at the same radius value. The spectrometer was calibrated using a previously characterized 14 MeV neutron beam produced in the ENEA Frascati Neutron Generator (FNG). The overall uncertainty of the spectrometer response matrix at 14 MeV, assessed on the basis of this experiment, was ±3%.

Use of sulfide-containing liquors for removing mercury from flue gases

Science.gov (United States)

Nolan, Paul S.; Downs, William; Bailey, Ralph T.; Vecci, Stanley J.

2006-05-02

A method and apparatus for reducing and removing mercury in industrial gases, such as a flue gas, produced by the combustion of fossil fuels, such as coal, adds sulfide ions to the flue gas as it passes through a scrubber. Ideally, the source of these sulfide ions may include at least one of: sulfidic waste water, kraft caustic liquor, kraft carbonate liquor, potassium sulfide, sodium sulfide, and thioacetamide. The sulfide ion source is introduced into the scrubbing liquor as an aqueous sulfide species. The scrubber may be either a wet or dry scrubber for flue gas desulfurization systems.

Optical amplifier operating at 1.3 microns useful for telecommunications and based on dysprosium-doped metal chloride host materials

Energy Technology Data Exchange (ETDEWEB)

Page, R.H.; Schaffers, K.I.; Payne, S.A.; Krupke, W.F.; Beach, R.J.

1997-12-02

Dysprosium-doped metal chloride materials offer laser properties advantageous for use as optical amplifiers in the 1.3 {micro}m telecommunications fiber optic network. The upper laser level is characterized by a millisecond lifetime, the host material possesses a moderately low refractive index, and the gain peak occurs near 1.31 {micro}m. Related halide materials, including bromides and iodides, are also useful. The Dy{sup 3+}-doped metal chlorides can be pumped with laser diodes and yield 1.3 {micro}m signal gain levels significantly beyond those currently available. 9 figs.

Optical amplifier operating at 1.3 microns useful for telecommunications and based on dysprosium-doped metal chloride host materials

Energy Technology Data Exchange (ETDEWEB)

Page, Ralph H. (San Ramon, CA); Schaffers, Kathleen I. (Pleasanton, CA); Payne, Stephen A. (Castro Valley, CA); Krupke, William F. (Pleasanton, CA); Beach, Raymond J. (Livermore, CA)

1997-01-01

Dysprosium-doped metal chloride materials offer laser properties advantageous for use as optical amplifiers in the 1.3 .mu.m telecommunications fiber optic network. The upper laser level is characterized by a millisecond lifetime, the host material possesses a moderately low refractive index, and the gain peak occurs near 1.31 .mu.m. Related halide materials, including bromides and iodides, are also useful. The Dy.sup.3+ -doped metal chlorides can be pumped with laser diodes and yield 1.3 .mu.m signal gain levels significantly beyond those currently available.

Thermoelectric properties of non-stoichiometric lanthanum sulfides

International Nuclear Information System (INIS)

Shapiro, E.; Danielson, L.R.

1983-01-01

The lanthanum sulfides are promising candidate materials for high-efficiency thermoelectric applications at temperatures up to 1300 0 C. The nonstoichiometric lanthanum sulfides (LaS /SUB x/ , where 1.33 2 //rho/ can be chosen. The thermal conductivity remains approximately constant with stoichiometry, so a material with an optimum value of α 2 //rho/ should possess the optimum figure-of-merit. Data for the Seebeck coefficient and electrical resistivity of non-stoichiometric lanthanum sulfides is presented, together with structural properties of these materials

Investigation on rare earth magnets recycling by organophosphoric extractant encapsulated polymeric beads for separation of dysprosium

International Nuclear Information System (INIS)

Yadav, Kartikey K.; Singh, D.K.; Kain, V.

2017-01-01

Rare earth elements (REEs) are a basic requirement of the electronics and new industries including green technology. In the present work an organophosphoric extractant encapsulating polyethersulfone (PES) beads has been developed and employed for dysprosium (Dy) separation from aqueous stream. Polyethersulfonic beads encapsulating PC88A were prepared by phase inversion method. During the synthesis of the beads, preparatory parameters were also optimized to obtain best suited beads which were subsequently characterized for their encapsulation capacity and micro structural investigation. The results obtained in the present investigation suggested that PES/PVAJPC88A composite beads could be used for separation of rare earths from aqueous medium obtained from the solubilisation of magnetic scrap materials

Comparison of Carbon XANES Spectra from an Iron Sulfide from Comet Wild 2 with an Iron Sulfide Interplanetary Dust Particle

Science.gov (United States)

Wirick, S.; Flynn, G. J.; Keller, L. P.; Sanford, S. A.; Zolensky, M. E.; Messenger, Nakamura K.; Jacobsen, C.

2008-01-01

Among one of the first particles removed from the aerogel collector from the Stardust sample return mission was an approx. 5 micron sized iron sulfide. The majority of the spectra from 5 different sections of this particle suggests the presence of aliphatic compounds. Due to the heat of capture in the aerogel we initially assumed these aliphatic compounds were not cometary but after comparing these results to a heated iron sulfide interplanetary dust particle (IDP) we believe our initial interpretation of these spectra was not correct. It has been suggested that ice coating on iron sulfides leads to aqueous alteration in IDP clusters which can then lead to the formation of complex organic compounds from unprocessed organics in the IDPs similar to unprocessed organics found in comets [1]. Iron sulfides have been demonstrated to not only transform halogenated aliphatic hydrocarbons but also enhance the bonding of rubber to steel [2,3]. Bromfield and Coville (1997) demonstrated using Xray photoelectron spectroscopy that "the surface enhancement of segregated sulfur to the surface of sulfided precipitated iron catalysts facilitates the formation of a low-dimensional structure of extraordinary properties" [4]. It may be that the iron sulfide acts in some way to protect aliphatic compounds from alteration due to heat.

Simultaneous removal of sulfide, nitrate and acetate: Kinetic modeling

International Nuclear Information System (INIS)

Wang Aijie; Liu Chunshuang; Ren Nanqi; Han Hongjun; Lee Duujong

2010-01-01

Biological removal of sulfide, nitrate and chemical oxygen demand (COD) simultaneously from industrial wastewaters to elementary sulfur (S 0 ), N 2 , and CO 2 , or named the denitrifying sulfide (DSR) process, is a cost effective and environmentally friendly treatment process for high strength sulfide and nitrate laden organic wastewater. Kinetic model for the DSR process was established for the first time on the basis of Activated Sludge Model No. 1 (ASM1). The DSR experiments were conducted at influent sulfide concentrations of 200-800 mg/L, whose results calibrate the model parameters. The model correlates well with the DSR process dynamics. By introducing the switch function and the inhibition function, the competition between autotrophic and heterotrophic denitrifiers is quantitatively described and the degree of inhibition of sulfide on heterotrophic denitrifiers is realized. The model output indicates that the DSR reactor can work well at 0.5 1000 mg/L influent sulfide, however, the DSR system will break down.

Hydrogen sulfide oxidation without oxygen - oxidation products and pathways

International Nuclear Information System (INIS)

Fossing, H.

1992-01-01

Hydrogen sulfide oxidation was studied in anoxic marine sediments-both in undisturbed sediment cores and in sediment slurries. The turn over of hydrogen sulfide was followed using 35 S-radiolabeled hydrogen sulfide which was injected into the sediment. However, isotope exchange reactions between the reduced sulfur compounds, in particular between elemental sulfur and hydrogen sulfide, influenced on the specific radioactivity of these pools. It was, therefore, not possible to measure the turn over rates of the reduced sulfur pools by the radiotracer technique but merely to use the radioisotope to demonstrate some of the oxidation products. Thiosulfate was one important intermediate in the anoxic oxidation of hydrogen sulfide and was continuously turned over by reduction, oxidation and disproportionation. The author discusses the importance of isotope exchange and also presents the results from experiments in which both 35 S-radiolabeled elemental sulfur, radiolabeled hydrogen sulfide and radiolabeled thiosulfate were used to study the intermediates in the oxidative pathways of the sulfur cycle

Reduction of produced elementary sulfur in denitrifying sulfide removal process.

Science.gov (United States)

Zhou, Xu; Liu, Lihong; Chen, Chuan; Ren, Nanqi; Wang, Aijie; Lee, Duu-Jong

2011-05-01

Denitrifying sulfide removal (DSR) processes simultaneously convert sulfide, nitrate, and chemical oxygen demand from industrial wastewater into elemental sulfur, dinitrogen gas, and carbon dioxide, respectively. The failure of a DSR process is signaled by high concentrations of sulfide in reactor effluent. Conventionally, DSR reactor failure is blamed for overcompetition for heterotroph to autotroph communities. This study indicates that the elementary sulfur produced by oxidizing sulfide that is a recoverable resource from sulfide-laden wastewaters can be reduced back to sulfide by sulfur-reducing Methanobacterium sp. The Methanobacterium sp. was stimulated with excess organic carbon (acetate) when nitrite was completely consumed by heterotrophic denitrifiers. Adjusting hydraulic retention time of a DSR reactor when nitrite is completely consumed provides an additional control variable for maximizing DSR performance.

Enhanced sulfidation xanthate flotation of malachite using ammonium ions as activator.

Science.gov (United States)

Wu, Dandan; Ma, Wenhui; Mao, Yingbo; Deng, Jiushuai; Wen, Shuming

2017-05-18

In this study, ammonium ion was used to enhance the sulfidation flotation of malachite. The effect of ammonium ion on the sulfidation flotation of malachite was investigated using microflotation test, inductively coupled plasma (ICP) analysis, zeta potential measurements, and scanning electron microscope analysis (SEM). The results of microflotation test show that the addition of sodium sulfide and ammonium sulfate resulted in better sulfidation than the addition of sodium sulfide alone. The results of ICP analysis indicate that the dissolution of enhanced sulfurized malachite surface is significantly decreased. Zeta potential measurements indicate that a smaller isoelectric point value and a large number of copper-sulfide films formed on the malachite surface by enhancing sulfidation resulted in a large amount of sodium butyl xanthate absorbed onto the enhanced sulfurized malachite surface. EDS semi-quantitative analysis and XPS analysis show that malachite was easily sulfurized by sodium sulfide with ammonium ion. These results show that the addition of ammonium ion plays a significant role in the sulfidation of malachite and results in improved flotation performance.

Physiological behavior of hydrogen sulfide in rice plant. Part 5. Effect of hydrogen sulfide on respiration of rice roots

Energy Technology Data Exchange (ETDEWEB)

Okajima, H; Takagi, S

1955-01-01

The inhibitory effects of hydrogen sulfide on the respiration of rice plant roots were investigated using Warburg's manometory technique. Hydrogen sulfide inhibited not only aerobic respiration but anaerobic respiration process of roots. Inhibitory action of hydrogen sulfide and potassium cyanide on the respiration were apparently reversible, but the style of recovery reaction from inhibition was somewhat different in each case. Oxygen consumption of roots was increased by addition of ammonium salts, but the same effects were not recognized by the addition of any other salt examined (except nitrate salts). There was close relationship between respiration of roots and assimilation of nitrogen by roots. The increased oxygen uptake by addition of ammonium salt was also inhibited by hydrogen sulfide. The reactivation of this reaction occurred with the recovery of endogenous respiration of roots. 19 references, 8 figures, 3 tables.

Enhanced sulfidation xanthate flotation of malachite using ammonium ions as activator

OpenAIRE

Dandan Wu; Wenhui Ma; Yingbo Mao; Jiushuai Deng; Shuming Wen

2017-01-01

In this study, ammonium ion was used to enhance the sulfidation flotation of malachite. The effect of ammonium ion on the sulfidation flotation of malachite was investigated using microflotation test, inductively coupled plasma (ICP) analysis, zeta potential measurements, and scanning electron microscope analysis (SEM). The results of microflotation test show that the addition of sodium sulfide and ammonium sulfate resulted in better sulfidation than the addition of sodium sulfide alone. The ...

Formation of Copper Sulfide Precipitate in Solid Iron

Science.gov (United States)

Urata, Kentaro; Kobayashi, Yoshinao

The growth rate of copper sulfide precipitates has been measured in low carbon steel samples such as Fe-0.3mass%Cu-0.03mass%S-0.1mass%C and Fe-0.1mass%Cu-0.01mass%S- 0.1mass%C. Heat-treatment of the samples was conducted at 1273, 1423 and 1573 K for 100 s - 14.4 ks for precipitation of copper sulfides and then the samples were observed by a scanning electron microscope and a transmission electron microscope to measure the diameter of copper sulfides precipitated in the samples. The growth rate of copper sulfide has been found to be well described by the Ostwald growth model, as follows: R\

An experimental study of Fe-Ni exchange between sulfide melt and olivine at upper mantle conditions: implications for mantle sulfide compositions and phase equilibria

Science.gov (United States)

Zhang, Zhou; von der Handt, Anette; Hirschmann, Marc M.

2018-03-01

The behavior of nickel in the Earth's mantle is controlled by sulfide melt-olivine reaction. Prior to this study, experiments were carried out at low pressures with narrow range of Ni/Fe in sulfide melt. As the mantle becomes more reduced with depth, experiments at comparable conditions provide an assessment of the effect of pressure at low-oxygen fugacity conditions. In this study, we constrain the Fe-Ni composition of molten sulfide in the Earth's upper mantle via sulfide melt-olivine reaction experiments at 2 GPa, 1200 and 1400 °C, with sulfide melt X_{{{Ni}}}^{{{Sulfide}}}={{Ni}}/{{Ni+{Fe}}} (atomic ratio) ranging from 0 to 0.94. To verify the approach to equilibrium and to explore the effect of {f_{{{O}2}}} on Fe-Ni exchange between phases, four different suites of experiments were conducted, varying in their experimental geometry and initial composition. Effects of Ni secondary fluorescence on olivine analyses were corrected using the PENELOPE algorithm (Baró et al., Nucl Instrum Methods Phys Res B 100:31-46, 1995), "zero time" experiments, and measurements before and after dissolution of surrounding sulfides. Oxygen fugacities in the experiments, estimated from the measured O contents of sulfide melts and from the compositions of coexisting olivines, were 3.0 ± 1.0 log units more reduced than the fayalite-magnetite-quartz (FMQ) buffer (suite 1, 2 and 3), and FMQ - 1 or more oxidized (suite 4). For the reduced (suites 1-3) experiments, Fe-Ni distribution coefficients K_{{D}}{}={(X_{{{Ni}}}^{{{sulfide}}}/X_{{{Fe}}}^{{{sulfide}}})}/{(X_{{{Ni}}^{{{olivine}}}/X_{{{Fe}}}^{{{olivine}}})}} are small, averaging 10.0 ± 5.7, with little variation as a function of total Ni content. More oxidized experiments (suite 4) give larger values of K D (21.1-25.2). Compared to previous determinations at 100 kPa, values of K D from this study are chiefly lower, in large part owing to the more reduced conditions of the experiments. The observed difference does not seem

Global use structures of the magnetic materials neodymium and dysprosium. A scenario-based analysis of the effect of the diffusion of electromobility on the demand for rare earths; Globale Verwendungsstrukturen der Magnetwerkstoffe Neodym und Dysprosium. Eine szenariobasierte Analyse der Auswirkung der Diffusion der Elektromobilitaet auf den Bedarf an Seltenen Erden

Energy Technology Data Exchange (ETDEWEB)

Gloeser-Chahoud, Simon; Kuehn, Andre; Tercero Espinoza, Luis

2016-06-15

Neodymium-iron-boron magnets (NdFeB) have experienced a significant demand as the most powerful permanent magnet in recent years, especially for the manufacture of compact electric servomotors with high efficiency and high power density, especially for mobile applications in hybrid traction motors and electric vehicles or for electric bikes. However, NdFeB magnets are also increasingly being used in general mechanical engineering (conveying and pumping systems, tools, air conditioning systems, lift motors, etc.), in the small electric motors of conventional passenger cars or in the generators of large wind power plants with permanent magnetic direct drive. Nevertheless, there is still high uncertainty in the use structures of NdFeB magnets and the contained rare earth elements neodymium and dysprosium. An effective instrument for increasing the market transparency and the understanding of complex anthropogenic material cycles is the dynamic material flow modeling. In the present work paper, this instrument is used for an in-depth analysis of the use structures of NdFeB magnets and the contained rare earths on a global scale. The dynamic modeling of product usage cycles reveals today's usage structures and quantifies future magnetic quantities in obsolete product flows. It could be shown that the magnets in today's scrap volume are mainly contained in obsolete electronics applications such as hard disks (HDD), CD and DVD drives, which makes the recycling hardly seem to be economical due to the small magnets and the high material spread, but in the foreseeable future with larger magnetic quantities from synchronous servomotors and generators can be expected, which significantly increases the recycling potential. In a further step, the effect of the diffusion of alternative drives in the automotive market on the dysprosium requirement is analyzed using a system dynamics model and possible adaptation mechanisms in the form of different substitution effects in

Nanoporous gold-based microbial biosensor for direct determination of sulfide.

Science.gov (United States)

Liu, Zhuang; Ma, Hanyue; Sun, Huihui; Gao, Rui; Liu, Honglei; Wang, Xia; Xu, Ping; Xun, Luying

2017-12-15

Environmental pollution caused by sulfide compounds has become a major problem for public health. Hence, there is an urgent need to explore a sensitive, selective, and simple sulfide detection method for environmental monitoring and protection. Here, a novel microbial biosensor was developed using recombinant Escherichia coli BL21 (E. coli BL21) expressing sulfide:quinone oxidoreductase (SQR) for sulfide detection. As an important enzyme involved in the initial step of sulfide metabolism, SQR oxidizes sulfides to polysulfides and transfers electrons to the electron transport chain. Nanoporous gold (NPG) with its unique properties was selected for recombinant E. coli BL21 cells immobilization, and then glassy carbon electrode (GCE) was modified by the resulting E. coli/NPG biocomposites to construct an E. coli/NPG/GCE bioelectrode. Due to the catalytic oxidation properties of NPG for sulfide, the electrochemical reaction of the E. coli/NPG/GCE bioelectrode is attributed to the co-catalysis of SQR and NPG. For sulfide detection, the E. coli/NPG/GCE bioelectrode showed a good linear response ranging from 50μM to 5mM, with a high sensitivity of 18.35μAmM -1 cm -2 and a low detection limit of 2.55μM. The anti-interference ability of the E. coli/NPG/GCE bioelectrode is better than that of enzyme-based inhibitive biosensors. Further, the E. coli/NPG/GCE bioelectrode was successfully applied to the detection of sulfide in wastewater. These unique properties potentially make the E. coli/NPG/GCE bioelectrode an excellent choice for reliable sulfide detection. Copyright © 2017 Elsevier B.V. All rights reserved.

Optical properties of zinc borotellurite glass doped with trivalent dysprosium ion

Science.gov (United States)

Ami Hazlin, M. N.; Halimah, M. K.; Muhammad, F. D.; Faznny, M. F.

2017-04-01

The zinc borotellurite doped with dysprosium oxide glass samples with chemical formula {[(TeO2) 0 . 7(B2O3) 0 . 3 ] 0 . 7(ZnO) 0 . 3 } 1 - x(Dy2O3)x (where x=0.01, 0.02, 0.03, 0.04 and 0.05 M fraction) were prepared by using conventional melt quenching technique. The structural and optical properties of the proposed glass systems were characterized by using X-ray diffraction (XRD) spectroscopy, Fourier Transform Infrared (FTIR) spectroscopy, and UV-VIS spectroscopy. The amorphous nature of the glass systems is confirmed by using XRD technique. The infrared spectra of the glass systems indicate three obvious absorption bands which are assigned to BO3 and TeO4 vibrational groups. Based on the absorption spectra obtained, the direct and indirect optical band gaps, as well as the Urbach energy were calculated. It is observed that both the direct and indirect optical band gaps increase with the concentration of Dy3+ ions. On the other hand, the Urbach energy is observed to decrease as the concentration of Dy3+ ions increases.

Spectrographic determination of dysprosium dopant in calcium sulphate used as dosimetric material

International Nuclear Information System (INIS)

Grigoletto, T.

1982-01-01

A spectrographic method is described for the quantitative determination of dysprosium in doped crystals of calcium sulphate. The consequences of the changes in some parameters of the excitation conditions, such as arc current, electrode type and total or partial burning of sample, in the analytical results are discussed. Matrix effects are investigated by comparison among analytical curves obtained from three different methods of standard preparations. Variations in the intensity of the spectral lines are verificated by recording the spectrum in distinct photographic plates (SA-1). The role of internal standard in analytical reproducibility and in counterbalance of the variations in the arc current and in the weight of sample are studied. The great similarity in excitation behavior of many of the rare earths is used to provide a high degree of internal standardization. Precision studies show a standard deviation of about + - 2,4 percent by use of lanthanum as an internal standard. Accuracy is estimate by comparative analysis of two calcium sulphate samples by X-Rays Fluorescence, Neutron Activation and Inductive Coupled Plasma (ICP) Emission Spectroscopy. (Author) [pt

LIGNOCELLULOSE NANOCOMPOSITE CONTAINING COPPER SULFIDE

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Sanchi Nenkova

2011-04-01

Full Text Available Copper sulfide-containing lignocellulose nanocomposites with improved electroconductivity were obtained. Two methods for preparing the copper sulfide lignocellulose nanocomposites were developed. An optimization of the parameters for obtaining of the nanocomposites with respect to obtaining improved electroconductivity, economy, and lower quantities and concentration of copper and sulfur ions in waste waters was conducted. The mechanisms and schemes of delaying and subsequent connection of copper sulfides in the lignocellulosic matrix were investigated. The modification with a system of 2 components: cupric sulfate pentahydrate (CuSO4. 5H2O and sodium thiosulfate pentahydrate (Na2S2O3.5H2O for wood fibers is preferred. Optimal parameters were established for the process: 40 % of the reduction system; hydromodule M=1:6; and ratio of cupric sulfate pentahydrate:sodium thiosulfate pentahydrate = 1:2. The coordinative connection of copper ions with oxygen atoms of cellulose OH groups and aromatic nucleus in lignin macromolecule was observed.

On the annealing behaviour of dysprosium ion implanted nickel: a combined study using Rutherford backscattering, transmission electron microscopy, and total current spectroscopy

International Nuclear Information System (INIS)

Chadderton, L.T.; Johnson, E.

1977-01-01

Despite continuing improvements in applications of the analytical method of Rutherford backscattering (RBS) to solid state physics it is recognized that more complete information can be obtained if other techniques - for example transmission electron microscopy (TEM) - are employed simultaneously. Experiments are described in which a combined RBS and TEM study of the annealing of nickel, rendered amorphous by implantation of 20 keV dysprosium ions is supplemented with a completely new technique - total current spectroscopy (TCS). In TCS low energy electrons (0-15 eV) are used to probe the damaged nickel. Observations have been made during annealing of both the reappearance of the bulk band structure of the metal and of a 'surface peak' which is highly sensitive to the recovery process. Changes in the height of the surface peak reveal three sharp annealing stages, the first two being preceded by reverse annealing which correlates well with RBS and TEM results. The first annealing stage - following the amorphous to crystalline transition - may be associated with electronic effects in the vicinity of the Curie point. Changes in the position of the surface peak allow one to trace the diffusion of dysprosium to the surface. Quantum mechanical resonances at the damage/crystal interface have also been followed throughout annealing. The initially amorphous layer (approximately 2.2nm) increases in thickness slightly during recovery. (Auth.)

Cuprous sulfide as a film insulation for superconductors

International Nuclear Information System (INIS)

Wagner, G.R.; Uphoff, J.H.; Vecchio, P.D.

1982-01-01

The LCP test coil utilizes a conductor of forced-flow design having 486 strands of multifilametary Nb 3 Sn compacted in a stainless steel sheath. The impetus for the work reported here stemmed from the need for some form of insulation for those strands to prevent sintering during reaction and to reduce ac losses. The work reported here experimented with cuprous sulfide coatings at various coating rates and thicknesses. Two solenoids that were wound with cuprous sulfide-coated wires and heat-treated at 700 degrees C were found to demonstrate that the film is effective in providing turn-to-turn insulation for less than about 0.5V between turns. The sulfide layer provided a metal-semiconductor junction which became conducting at roughly 0.5V. Repeated cycling of the coil voltage in excess of that value produced no damage to the sulfide layer. The junction provided self-protection for the coil as long as the upper allowable current density in the sulfide was not exceeded. No training was apparent up to 6.4 T

Remediation of Sulfidic Wastewater by Aeration in the Presence of Ultrasonic Vibration

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F. Ahmad

2018-06-01

Full Text Available In the current study, the aerial oxidation of sodium sulfide in the presence of ultrasonic vibration is investigated. Sulfide analysis was carried out by the methylene blue method. Sodium sulfide is oxidized to elemental sulfur in the presence of ultrasonic vibration. The influence of air flow rate, initial sodium sulfide concentration and ultrasonic vibration intensity on the oxidation of sodium sulfide was investigated. The rate law equation regarding the oxidation of sulfide was determined from the experimental data. The order of reaction with respect to sulfide and oxygen was found to be 0.36 and 0.67 respectively. The overall reaction followed nearly first order kinetics.

Girdler-sulfide process physical properties

International Nuclear Information System (INIS)

Neuburg, H.J.; Atherley, J.F.; Walker, L.G.

1977-05-01

Physical properties of pure hydrogen sulfide and of gaseous and liquid solutions of the H 2 S-H 2 O system have been formulated. Tables for forty-nine different properties in the pressure and temperature range of interest to the Girdler-Sulfide (GS) process for heavy water production are given. All properties are presented in SI units. A computer program capable of calculating properties of the pure components as well as gaseous mixtures and liquid solutions at saturated and non-saturated conditions is included. (author)

Hydrogen sulfide production from cysteine and homocysteine by periodontal and oral bacteria.

Science.gov (United States)

Yoshida, Akihiro; Yoshimura, Mamiko; Ohara, Naoya; Yoshimura, Shigeru; Nagashima, Shiori; Takehara, Tadamichi; Nakayama, Koji

2009-11-01

Hydrogen sulfide is one of the predominant volatile sulfur compounds (VSCs) produced by oral bacteria. This study developed and evaluated a system for detecting hydrogen sulfide production by oral bacteria. L-methionine-alpha-deamino-gamma-mercaptomethane-lyase (METase) and beta carbon-sulfur (beta C-S) lyase were used to degrade homocysteine and cysteine, respectively, to produce hydrogen sulfide. Enzymatic reactions resulting in hydrogen sulfide production were assayed by reaction with bismuth trichloride, which forms a black precipitate when mixed with hydrogen sulfide. The enzymatic activities of various oral bacteria that result in hydrogen sulfide production and the capacity of bacteria from periodontal sites to form hydrogen sulfide in reaction mixtures containing L-cysteine or DL-homocysteine were assayed. With L-cysteine as the substrate, Streptococcus anginosus FW73 produced the most hydrogen sulfide, whereas Porphyromonas gingivalis American Type Culture Collection (ATCC) 33277 and W83 and Fusobacterium nucleatum ATCC 10953 produced approximately 35% of the amount produced by the P. gingivalis strains. Finally, the hydrogen sulfide found in subgingival plaque was analyzed. Using bismuth trichloride, the hydrogen sulfide produced by oral bacteria was visually detectable as a black precipitate. Hydrogen sulfide production by oral bacteria was easily analyzed using bismuth trichloride. However, further innovation is required for practical use.

Sulfidation of alumina-supported iron and iron-molybdenum oxide catalysts

NARCIS (Netherlands)

Ramselaar, W.L.T.M.; Crajé, M.W.J.; Hadders, R.H.; Gerkema, E.; Beer, de V.H.J.; Kraan, van der A.M.

1990-01-01

The transition of alumina-supported iron and iron-molybdenum catalysts from the oxidic precursor to the sulfided catalysts was systematically studied by means of in-situ Mössbauer spectroscopy at room temperature. This enabled the adjudgement of various sulfidic phases in the sulfided catalysts. The

Red coloration by heat treatment of the coprecipitate of cadmium sulfide and mercury(II) sulfide prepared from the nitrates

International Nuclear Information System (INIS)

Nakahara, Fujiya

1979-01-01

The effects of starting salts on the color, particle size and crystal structure of mercury-cadmium-sulfide pigments were investigated. The coprecipitate (N-S) of cadmium sulfide and mercury (II) sulfide was prepared by adding sodium sulfide solution to a mixed cadmium-mercury (II) nitrate solution. The coprecipitate (C-S) of cadmium sulfide and mercury (II) sulfide was also prepared from the mixed solution of their chlorides by the same method as described above. The coprecipitated products were heat-treated (calcination or hydrothermal treatment) at 350 0 C for 2 hours and subsequent changes in powder properties of both products were compared from each other. The powder properties of N-S, C-S and their heat-treated products were investigated by spectral reflectance, electron microscopy, X-ray diffraction and specific surface area measurements. Sample (N-C) obtained by the calcination of N-S was brown, indicating no red coloration, but the calcined product (C-C) of C-S developed a red color. Cl - and hot water were found to be effective for the red color development of the pigment. The effectiveness was confirmed by calcining N-S in the presence of NaCl or by treating it hydrothermally. It was found that halides other than NaCl, (e.g., NH 4 Cl, KCl, KBr and KI), were also effective for the color development of the pigment. The red samples are solid solutions with a basically hexagonal CdS structure, and it appears that CdS takes up HgS without any apparent structural changes. The particle size of the red samples are larger than those of the non red samples. (author)

A method for measuring sulfide toxicity in the nematode Caenorhabditis elegans.

Science.gov (United States)

Livshits, Leonid; Gross, Einav

2017-01-01

Cysteine catabolism by gut microbiota produces high levels of sulfide. Excessive sulfide can interfere with colon function, and therefore may be involved in the etiology and risk of relapse of ulcerative colitis, an inflammatory bowel disease affecting millions of people worldwide. Therefore, it is crucial to understand how cells/animals regulate the detoxification of sulfide generated by bacterial cysteine catabolism in the gut. Here we describe a simple and cost-effective way to explore the mechanism of sulfide toxicity in the nematode Caenorhabditis elegans ( C. elegans ). •A rapid cost-effective method to quantify and study sulfide tolerance in C. elegans and other free-living nematodes.•A cost effective method to measure the concentration of sulfide in the inverted plate assay.

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.

Sulfidation of carbon-supported iron oxide catalysts

NARCIS (Netherlands)

Ramselaar, W.L.T.M.; Hadders, R.H.; Gerkema, E.; Beer, de V.H.J.; Oers, van E.M.; Kraan, van der A.M.

1989-01-01

The sulfidation of carbon-supported iron oxide catalysts was studied by means of in-situ Mössbauer spectroscopy at temperatures down to 4.2 K. The catalysts were dried in two different ways and then sulfided in a flow of 10% H2S in H2 at temperatures between 293 and 773 K. Thiophene

Optimization of the superconducting phase of hydrogen sulfide

Science.gov (United States)

Degtyarenko, N. N.; Masur, E. A.

2015-12-01

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.

Chemical dissolution of sulfide minerals

Science.gov (United States)

Chao, T.T.; Sanzolone, R.F.

1977-01-01

Chemical dissolution treatments involving the use of aqua regia, 4 N HNO3, H2O2-ascorbic acid, oxalic acid, KClO3+HCl, and KClO3+HCl followed by 4 N HNO3 were applied to specimens of nine common sulfide minerals (galena, chalcopyrite, cinnabar, molybdenite, orpiment, pyrite, stibnite, sphalerite, and tetrahedrite) mixed individually with a clay loam soil. The resultant decrease in the total sulfur content of the mixture, as determined by using the Leco induction furnace, was used to evaluate the effectiveness of each chemical treatment. A combination of KClO3+HCl followed by 4 N HNO3 boiling gently for 20 min has been shown to be very effective in dissolving all the sulfide minerals. This treatment is recommended to dissolve metals residing in sulfide minerals admixed with secondary weathering products, as one step in a fractionation scheme whereby metals in soluble and adsorbed forms, and those associated with organic materials and secondary oxides, are first removed by other chemical extractants.

Lanthanide complexes as luminogenic probes to measure sulfide levels in industrial samples

International Nuclear Information System (INIS)

Thorson, Megan K.; Ung, Phuc; Leaver, Franklin M.; Corbin, Teresa S.; Tuck, Kellie L.; Graham, Bim; Barrios, Amy M.

2015-01-01

A series of lanthanide-based, azide-appended complexes were investigated as hydrogen sulfide-sensitive probes. Europium complex 1 and Tb complex 3 both displayed a sulfide-dependent increase in luminescence, while Tb complex 2 displayed a decrease in luminescence upon exposure to NaHS. The utility of the complexes for monitoring sulfide levels in industrial oil and water samples was investigated. Complex 3 provided a sensitive measure of sulfide levels in petrochemical water samples (detection limit ∼ 250 nM), while complex 1 was capable of monitoring μM levels of sulfide in partially refined crude oil. - Highlights: • Lanthanide–azide based sulfide sensors were synthesized and characterized. • The probes have excitation and emission profiles compatible with sulfide-contaminated samples from the petrochemical industry. • A terbium-based probe was used to measure the sulfide concentration in oil refinery wastewater. • A europium-based probe had compatibility with partially refined crude oil samples.

Lanthanide complexes as luminogenic probes to measure sulfide levels in industrial samples

Energy Technology Data Exchange (ETDEWEB)

Thorson, Megan K. [Department of Medicinal Chemistry, University of Utah College of Pharmacy, Salt Lake City, UT 84108 (United States); Ung, Phuc [Monash Institute of Pharmaceutical Sciences, Monash University, Victoria 3052 (Australia); Leaver, Franklin M. [Water & Energy Systems Technology, Inc., Kaysville, UT 84037 (United States); Corbin, Teresa S. [Quality Services Laboratory, Tesoro Refining and Marketing, Salt Lake City, UT 84103 (United States); Tuck, Kellie L., E-mail: kellie.tuck@monash.edu [School of Chemistry, Monash University, Victoria 3800 (Australia); Graham, Bim, E-mail: bim.graham@monash.edu [Monash Institute of Pharmaceutical Sciences, Monash University, Victoria 3052 (Australia); Barrios, Amy M., E-mail: amy.barrios@utah.edu [Department of Medicinal Chemistry, University of Utah College of Pharmacy, Salt Lake City, UT 84108 (United States)

2015-10-08

A series of lanthanide-based, azide-appended complexes were investigated as hydrogen sulfide-sensitive probes. Europium complex 1 and Tb complex 3 both displayed a sulfide-dependent increase in luminescence, while Tb complex 2 displayed a decrease in luminescence upon exposure to NaHS. The utility of the complexes for monitoring sulfide levels in industrial oil and water samples was investigated. Complex 3 provided a sensitive measure of sulfide levels in petrochemical water samples (detection limit ∼ 250 nM), while complex 1 was capable of monitoring μM levels of sulfide in partially refined crude oil. - Highlights: • Lanthanide–azide based sulfide sensors were synthesized and characterized. • The probes have excitation and emission profiles compatible with sulfide-contaminated samples from the petrochemical industry. • A terbium-based probe was used to measure the sulfide concentration in oil refinery wastewater. • A europium-based probe had compatibility with partially refined crude oil samples.

Watt-level dysprosium fiber laser at 3.15  μm with 73% slope efficiency.

Science.gov (United States)

Woodward, R I; Majewski, M R; Bharathan, G; Hudson, D D; Fuerbach, A; Jackson, S D

2018-04-01

Rare-earth-doped fiber lasers are emerging as promising high-power mid-infrared sources for the 2.6-3.0 μm and 3.3-3.8 μm regions based on erbium and holmium ions. The intermediate wavelength range, however, remains vastly underserved, despite prospects for important manufacturing and defense applications. Here, we demonstrate the potential of dysprosium-doped fiber to solve this problem, with a simple in-band pumped grating-stabilized linear cavity generating up to 1.06 W at 3.15 μm. A slope efficiency of 73% with respect to launched power (77% relative to absorbed power) is achieved-the highest value for any mid-infrared fiber laser to date, to the best of our knowledge. Opportunities for further power and efficiency scaling are also discussed.

The solubility of iron sulfides and their role in mass transport in Girdler-Sulfide heavy water plants

International Nuclear Information System (INIS)

Tewari, P.H.; Wallace, G.; Campbell, A.B.

1978-04-01

The solubilities of several iron sulfides, mackinawite FeSsub((1-x)), troilite FeS, pyrrhotite Fesub((1-x))S (monoclinic and hexagonal), and pyrite FeS 2 have been determined in aqueous H 2 S solution at 0.1 MPa and 1.8 MPa H 2 S pressures between 25 deg and 125 deg C. The dependence of solubility on the pH of the medium has also been studied. It is concluded that since mackinawite is the most soluble of the iron sulfides, and has the highest dissolution rate and the steepest decline in solubility with temperature, its prolonged formation during plant operation should be avoided to minimize iron transport from lower to higher temperature areas in Girdler-Sulfide (G.S.) heavy water plants. This can be achieved by a preconditioning of carbon steel surfaces to convert mackinawite to pyrrhotite and pyrite

Laser cleaning of sulfide scale on compressor impeller blade

International Nuclear Information System (INIS)

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

2015-01-01

Highlights: • The effects of sulfide layers and fluence values on the mechanism of laser cleaning were experimentally established. • The specimen surface with sulfide scale becomes slightly smoother than that before laser cleaning. • The mechanism of laser cleaning the sulfide scale of stainless steel is spallation without oxidization. • It would avoid chemical waste and dust pollution using a fiber laser instead of using nitric acids or sandblasting. - Abstract: 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.

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.

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,

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.

Process for scavenging hydrogen sulfide from hydrocarbon gases

International Nuclear Information System (INIS)

Fox, I.

1981-01-01

A process for scavenging hydrogen sulfide from hydrocarbon gases utilizes iron oxide particles of unique chemical and physical properties. These particles have large surface area, and are comprised substantially of amorphous Fe 2 O 3 containing a crystalline phase of Fe 2 O 3 , Fe 3 O 4 and combinations thereof. In scavenging hydrogen sulfide, the iron oxide particles are suspended in a liquid which enters into intimate mixing contact with hydrocarbon gases; the hydrogen sulfide is reacted at an exceptional rate and only acid-stable reaction products are formed. Thereafter, the sweetened hydrocarbon gases are collected

Denitrifying sulfide removal process on high-salinity wastewaters.

Science.gov (United States)

Liu, Chunshuang; Zhao, Chaocheng; Wang, Aijie; Guo, Yadong; Lee, Duu-Jong

2015-08-01

Denitrifying sulfide removal (DSR) process comprising both heterotrophic and autotrophic denitrifiers can simultaneously convert nitrate, sulfide, and acetate into nitrogen gas, elemental sulfur (S(0)), and carbon dioxide, respectively. Sulfide- and nitrate-laden wastewaters at 2-35 g/L NaCl were treated by DSR process. A C/N ratio of 3:1 was proposed to maintain high S(0) conversion rate. The granular sludge with a compact structure and smooth outer surface was formed. The microbial communities of DSR consortium via high-throughput sequencing method suggested that salinity shifts the predominating heterotrophic denitrifiers at 10 g/L NaCl.

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.

Is succession in wet calcareous dune slacks affected by free sulfide?

NARCIS (Netherlands)

Adema, EB; van Gemerden, H; Grootjans, AP; Adema, Erwin B.; Grootjans, Ab P.; Rapson, G.

Consequences of sulfide toxicity on succession in wet calcareous dune slacks were investigated. Sulfide may exert an inhibitory effect on dune slack plants, but several pioneer species exhibit ROL (Radial Oxygen Loss) and thereby protect themselves against free sulfide. Under oxic conditions free

Magnetic anisotropy of dysprosium(III) in a low-symmetry environment: a theoretical and experimental investigation.

Science.gov (United States)

Bernot, Kevin; Luzon, Javier; Bogani, Lapo; Etienne, Mael; Sangregorio, Claudio; Shanmugam, Muralidharan; Caneschi, Andrea; Sessoli, Roberta; Gatteschi, Dante

2009-04-22

A mixed theoretical and experimental approach was used to determine the local magnetic anisotropy of the dysprosium(III) ion in a low-symmetry environment. The susceptibility tensor of the monomeric species having the formula [Dy(hfac)(3)(NIT-C(6)H(4)-OEt)(2)], which contains nitronyl nitroxide (NIT-R) radicals, was determined at various temperatures through angle-resolved magnetometry. These results are in agreement with ab initio calculations performed using the complete active space self-consistent field (CASSCF) method, validating the predictive power of this theoretical approach for complex systems containing rare-earth ions, even in low-symmetry environments. Susceptibility measurements performed with the applied field along the easy axis eventually permitted a detailed analysis of the temperature and field dependence of the magnetization, providing evidence that the Dy ion transmits an antiferromagnetic interaction between radicals but that the Dy-radical interaction is ferromagnetic.

Titanocene sulfide chemistry

Czech Academy of Sciences Publication Activity Database

Horáček, Michal

2016-01-01

Roč. 314, MAY 2016 (2016), s. 83-102 ISSN 0010-8545 R&D Projects: GA ČR(CZ) GAP207/12/2368 Institutional support: RVO:61388955 Keywords : titanocene sulfide chemistry * photolysis * titanocene hydrosulfides Ti-(SH)n Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 13.324, year: 2016

Iron-sulfide redox flow batteries

Science.gov (United States)

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.

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

International Nuclear Information System (INIS)

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

2011-01-01

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.

Isolation of Ochrobactrum sp.QZ2 from sulfide and nitrite treatment system

International Nuclear Information System (INIS)

Mahmood, Qaisar; Hu Baolan; Cai Jing; Zheng Ping; Azim, Muhammad Rashid; Jilani, Ghulam; Islam, Ejazul

2009-01-01

A bacterial strain QZ2 was isolated from sludge of anoxic sulfide-oxidizing (ASO) reactor. Based on 16S rDNA sequence analysis and morphology, the isolate was identified as Ochrobactrum sp. QZ2. The strain was facultative chemolithotroph, able of using sulfide to reduce nitrite anaerobically. It produced either elemental sulfur or sulfate as the product of sulfide oxidation, depending on the initial sulfide and nitrite concentrations. The optimum growth pH and temperature for Ochrobactrum sp. QZ2 were found as 6.5-7.0 and 30 deg. C, respectively. The specific growth rate (μ) was found as 0.06 h -1 with a doubling time of 19.75 h; the growth seemed more sensitive to highly alkaline pH. Ochrobactrum sp. QZ2 catalyzed sulfide oxidation to sulfate was more sensitive to sulfide compared with nitrite as indicated by IC 50 values for sulfide and nitrite utilization implying that isolate was relatively more tolerant to nitrite. The comparison of physiology of Ochrobactrum sp. QZ2 with those of other known sulfide-oxidizing bacteria suggested that the present isolate resembled to Ochrobactrum anthropi in its denitrification ability.

Sulfide Oxidation in the Anoxic Black-Sea Chemocline

DEFF Research Database (Denmark)

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

1991-01-01

per day, occurred in anoxic water at the top of the sulfide zone concurrent with the highest rates of dark CO2 assimilation. The main soluble oxidized products of sulfide were thiosulfate (68-82%) and sulfate. Indirect evidence was presented for the formation of elemental sulfur which accumulated...... 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....

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

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

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.

Sulindac Sulfide, but Not Sulindac Sulfone, Inhibits Colorectal Cancer Growth

Directory of Open Access Journals (Sweden)

Christopher S. Williams

1999-06-01

Full Text Available Sulindac sulfide, a metabolite of the nonsteroidal antiinflammatory drug (NSAID sulindac sulfoxide, is effective at reducing tumor burden in both familial adenomatous polyposis patients and in animals with colorectal cancer. Another sulindac sulfoxide metabolite, sulindac sulfone, has been reported to have antitumor properties without inhibiting cyclooxygenase activity. Here we report the effect of sulindac sulfone treatment on the growth of colorectal carcinoma cells. We observed that sulindac sulfide or sulfone treatment of HCA-7 cells led to inhibition of prostaglandin E2 production. Both sulindac sulfide and sulfone inhibited HCA-7 and HCT-116 cell growth in vitro. Sulindac sulfone had no effect on the growth of either HCA-7 or HCT-116 xenografts, whereas the sulfide derivative inhibited HCA-7 growth in vivo. Both sulindac sulfide and sulfone inhibited colon carcinoma cell growth and prostaglandin production in vitro, but sulindac sulfone had no effect on the growth of colon cancer cell xenografts in nude mice.

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

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).

A sulfidation-resistant nickel-base alloy

International Nuclear Information System (INIS)

Lai, G.Y.

1989-01-01

For applications in mildly to moderately sulfidizing environments, stainless steels, Fe-Ni-Cr alloys (e.g., alloys 800 and 330), and more recently Fe-Ni-Cr-Co alloys (e.g., alloy 556) are frequently used for construction of process equipment. However, for many highly sulfidizing environments, few existing commercial alloys have adequate performance. Thus, a new nickel-based alloy containing 27 wt.% Co, 28 wt.% Cr, 4 wt.% Fe, 2.75 wt.% Si, 0.5 wt.% Mn and 0.05 wt.% C (Haynes alloy HR-160) was developed

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.

Isotopic shifts and configuration mixing in the dysprosium II spectrum

International Nuclear Information System (INIS)

Aufmuth, P.

1977-01-01

Using a photoelectric Fabry-Perot spectrometer with digital data acquisition, the isotopic shifts of all stable dysprosium isotopes (Z = 66, A = 156, 158, 160, 161, 162, 163, 164) have been measured in transitions from the groundstate configuration 4f 10 6s to the excited configurations 4f 9 5d6s, 4f 9 5d 2 , and 4f 10 6p of the spark spectrum. Mass and volume effects have been seperated; the results are compared with arc spectrum measurements. From the volume effect of a pure s-p transition the change of the mean electric quadratic nuclear radius delta 2 > has been calculated. In order to test fine structure calculations of the Dy II spectrum, the isotopic shifts of 29 lines of the isotopes 162 Dy and 164 Dy have been measured. Based on the sharing rule, the reported configuration mixing could be confirmed in principle; for one energy level (E = 22908 K) the asignement has been proved to be false, in the case of three other levels (E = 22467, 22672, and 28885 K) the asignement is doubtfull. For the ground state levels 4f 10 6s 6 I the influence of relativistic effects could be proved; these effects can be interpreted in the framework of a parametric representation of the isotopic shift. The order of magnitude of the crossed second order effects has been estimated. (orig.) [de

Surface modification of malachite with ethanediamine and its effect on sulfidization flotation

Science.gov (United States)

Feng, Qicheng; Zhao, Wenjuan; Wen, Shuming

2018-04-01

Ethanediamine was used to modify the mineral surface of malachite to improve its sulfidization and flotation behavior. The activation mechanism was investigated by adsorption experiments, X-ray photoelectron spectroscopy (XPS) analysis, and zeta potential measurements. Microflotation experiments showed that the flotation recovery of malachite was enhanced after the pretreatment of the mineral particles with ethanediamine prior to the addition of Na2S. Adsorption tests revealed that numerous sulfide ion species in the pulp solution were transferred onto the mineral surface through the formation of more copper sulfide species. This finding was confirmed by the results of the XPS measurements. Ethanediamine modification not only increased the contents of copper sulfide species on the malachite surface but also enhanced the reactivity of the sulfidization products. During sulfidization, Cu(II) species on the mineral surface were reduced into Cu(I) species, and the percentages of S22- and Sn2- relative to the total S increased after modification, resulting in increased surface hydrophobicity. The results of zeta potential measurements showed that the ethanediamine-modified mineral surface adsorbed with more sulfide ion species was advantageous to the attachment of xanthate species, thereby improving malachite floatability. The proposed ethanediamine modification followed by sulfidization xanthate flotation exhibits potential for industrial application.

Bioavailability and stability of mercury sulfide in Armuchee (USA) soil

International Nuclear Information System (INIS)

Han, Fengxiang; Shiyab, Safwan; Su, Yi; Monts, David L.; Waggoner, Charles A.; Matta, Frank B.

2007-01-01

Because of the adverse effects of elemental mercury and mercury compounds upon human health, the U.S. Department of Energy (DOE) is engaged in an on-going effort to monitor and remediate mercury-contaminated DOE sites. In order to more cost effectively implement those extensive remediation efforts, it is necessary to obtain an improved understanding of the role that mercury and mercury compounds play in the ecosystem. We have conducted pilot scale experiments to study the bioavailability of mercury sulfide in an Armuchee (eastern US ) soil. The effects of plants and incubation time on chemical stability and bioavailability of HgS under simulated conditions of the ecosystem have been examined, as has the dynamics of the dissolution of mercury sulfide by various extractants. The results show that mercury sulfide in contaminated Armuchee soil was still to some extent bioavailable to plants. After planting, soil mercury sulfide is more easily dissolved by both 4 M and 12 M nitric acid than pure mercury sulfide reagent. Dissolution kinetics of soil mercury sulfide and pure chemical reagent by nitric acid are different. Mercury release by EDTA from HgS-contaminated soil increased with time of reaction and soil mercury level. Chelating chemicals increase the solubility and bioavailability of mercury in HgS-contaminated soil. (authors)

Effect of Sulfide Concentration on Copper Corrosion in Anoxic Chloride-Containing Solutions

Science.gov (United States)

Kong, Decheng; Dong, Chaofang; Xu, Aoni; Man, Cheng; He, Chang; Li, Xiaogang

2017-04-01

The structure and property of passive film on copper are strongly dependent on the sulfide concentration; based on this, a series of electrochemical methods were applied to investigate the effect of sulfide concentration on copper corrosion in anaerobic chloride-containing solutions. The cyclic voltammetry and x-ray photoelectron spectroscopy analysis demonstrated that the corrosion products formed on copper in anaerobic sulfide solutions comprise Cu2S and CuS. And the corrosion resistance of copper decreased with increasing sulfide concentration and faster sulfide addition, owing to the various structures of the passive films observed by the atomic force microscope and scanning electron microscope. A p-type semiconductor character was obtained under all experimental conditions, and the defect concentration, which had a magnitude of 1022-1023 cm-3, increased with increasing sulfide concentration, resulting in a higher rate of both film growth and dissolution.

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.

Use of dispersive liquid-liquid microextraction for simultaneous preconcentration of samarium, europium, gadolinium and dysprosium

International Nuclear Information System (INIS)

Mallah, M.H.; Atomic Energy Organization of Iran, Tehran; Shemirani, F.; Ghannadi Maragheh, M.

2008-01-01

A new preconcentration method of dispersive liquid-liquid microextraction (DLLME) was developed for simultaneous preconcentration of samarium, europium, gadolinium and dysprosium. DLLME technique was successfully used as a sample preparation method. In this preconcentration method, an appropriate mixture of extraction solvent, disperser solvent was injected rapidly into an aqueous solution containing Sm, Eu, Gd and Dy after complex formation using chelating reagent of the 1-(2-pyridylazo)-2-naphthol (PAN). After phase separation, 0.5 mL of the settled phase containing enriched analytes was determined by inductively coupled plasma optical emission spectrometry (ICP-OES). The main factors affected the preconcentration of Sm, Eu, Gd and Dy were extraction and dispersive solvent type and their volume, extraction time, volume of chelating agent (PAN), centrifuge speed and drying temperature of the samples. Under the best operating condition simultaneous preconcentration factors of 80, 100, 103 and 78 were obtained for Sm, Eu, Gd and Dy, respectively. (author)

Oxide perovskites with tetravalent dysprosium and compounds of the type Ba/sub 3/RE/sub 4/O/sub 9/ (RE = Rare Earth Element)

Energy Technology Data Exchange (ETDEWEB)

Brauer, G; Kristen, H [Freiburg Univ. (Germany, F.R.)

1980-03-01

In analogy to our investigations concerning tetravalent Nd in oxide perovskites, we also tried to stabilize dysprosium(IV) by incorporation in host-lattices with the perovskite structure. As host-lattices we used BaCeO/sub 3/, BaTbO/sub 3/, and SrTbO/sub 3/. Only in Ba(Ce, Dy)O/sub 3/ we could trace Dy(IV) with certainty. Among the prepared mixed oxides, also the phase Ba/sub 3/Dy/sub 4/O/sub 9/ occured. The lattice parameters of several phases of this latter type were redetermined.

Quantitative prediction process and evaluation method for seafloor polymetallic sulfide resources

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Mengyi Ren

2016-03-01

Full Text Available Seafloor polymetallic sulfide resources exhibit significant development potential. In 2011, China received the exploration rights for 10,000 km2 of a polymetallic sulfides area in the Southwest Indian Ocean; China will be permitted to retain only 25% of the area in 2021. However, an exploration of seafloor hydrothermal sulfide deposits in China remains in the initial stage. According to the quantitative prediction theory and the exploration status of seafloor sulfides, this paper systematically proposes a quantitative prediction evaluation process of oceanic polymetallic sulfide resources and divides it into three stages: prediction in a large area, prediction in the prospecting region, and the verification and evaluation of targets. The first two stages of the prediction process have been employed in seafloor sulfides prospecting of the Chinese contract area. The results of stage one suggest that the Chinese contract area is located in the high posterior probability area, which indicates good prospecting potential area in the Indian Ocean. In stage two, the Chinese contract area of 48°–52°E has the highest posterior probability value, which can be selected as the reserved region for additional exploration. In stage three, the method of numerical simulation is employed to reproduce the ore-forming process of sulfides to verify the accuracy of the reserved targets obtained from the three-stage prediction. By narrowing the exploration area and gradually improving the exploration accuracy, the prediction will provide a basis for the exploration and exploitation of seafloor polymetallic sulfide resources.

New cyclic sulfides, garlicnins I2, M, N, and O, from Allium sativum.

Science.gov (United States)

Nohara, Toshihiro; Ono, Masateru; Nishioka, Naho; Masuda, Fuka; Fujiwara, Yukio; Ikeda, Tsuyoshi; Nakano, Daisuke; Kinjo, Junei

2018-01-01

One atypical thiolane-type sulfide, garlicnin I 2 (1), two 3,4-dimethylthiolane-type sulfides, garlicnins M (2) and N (3), and one thiabicyclic-type sulfide, garlicnin O (4), were isolated from the acetone extracts of Chinese garlic bulbs, Allium sativum and their structures were characterized. Hypothetical pathways for the production of the respective sulfides were discussed.

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

International Nuclear Information System (INIS)

Chen Chuan; Ren Nanqi; Wang Aijie; Liu Lihong; Lee, Duu-Jong

2010-01-01

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.

Adaptation of cyanobacteria to the sulfide-rich microenvironment of black band disease of coral.

Science.gov (United States)

Myers, Jamie L; Richardson, Laurie L

2009-02-01

Black band disease (BBD) is a cyanobacteria-dominated microbial mat that migrates across living coral colonies lysing coral tissue and leaving behind exposed coral skeleton. The mat is sulfide-rich due to the presence of sulfate-reducing bacteria, integral members of the BBD microbial community, and the sulfide they produce is lethal to corals. The effect of sulfide, normally toxic to cyanobacteria, on the photosynthetic capabilities of five BBD cyanobacterial isolates of the genera Geitlerinema (3), Leptolyngbya (1), and Oscillatoria (1) and six non-BBD cyanobacteria of the genera Leptolyngbya (3), Pseudanabaena (2), and Phormidium (1) was examined. Photosynthetic experiments were performed by measuring the photoincorporation of [(14)C] NaHCO(3) under the following conditions: (1) aerobic (no sulfide), (2) anaerobic with 0.5 mM sulfide, and (3) anaerobic with 0.5 mM sulfide and 10 microM 3-(3',4'-dichlorophenyl)-1,1-dimethylurea (DCMU). All five BBD cyanobacterial isolates tolerated sulfide by conducting sulfide-resistant oxygenic photosynthesis. Five of the non-BBD cyanobacterial isolates did not tolerate sulfide, although one Pseudanabaena isolate continued to photosynthesize in the presence of sulfide at a considerably reduced rate. None of the isolates conducted anoxygenic photosynthesis with sulfide as an electron donor. This is the first report on the physiology of a culture of Oscillatoria sp. found globally in BBD.

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

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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.

Nanostructured silver sulfide: synthesis of various forms and their application

Science.gov (United States)

Sadovnikov, S. I.; Rempel, A. A.; Gusev, A. I.

2018-04-01

The results of experimental studies on nanostructured silver sulfide are analyzed and generalized. The influence of small particle size on nonstoichiometry of silver sulfide is discussed. Methods for the synthesis of various forms of nanostructured Ag2S including nanopowders, stable colloidal solutions, quantum dots, core–shell nanoparticles and heteronanostructures are described. The advantages and drawbacks of different synthetic procedures are analyzed. Main fields of application of nanostructured silver sulfide are considered. The bibliography includes 184 references.

Production and Preservation of Sulfide Layering in Mercury's Magma Ocean

Science.gov (United States)

Boukare, C.-E.; Parman, S. W.; Parmentier, E. M.; Anzures, B. A.

2018-05-01

Mercury's magma ocean (MMO) would have been sulfur-rich. At some point during MMO solidification, it likely became sulfide saturated. Here we present physiochemical models exploring sulfide layer formation and stability.

Effects of Wood Pollution on Pore-Water Sulfide Levels and Eelgrass Germination

Science.gov (United States)

Ekelem, C.

2016-02-01

Historically, sawmills released wood waste onto coastal shorelines throughout the Pacific Northwest of the USA, enriching marine sediments with organic material. The increase in organic carbon boosts the bacterial reduction of sulfate and results in the production of a toxic metabolite, hydrogen sulfide. Hydrogen sulfide is a phytotoxin and can decrease the growth and survival of eelgrass. This is a critical issue since eelgrass, Zostera marina, forms habitat for many species, stabilizes sediment, and plays a role in nutrient cycling and sediment chemistry. The objective of our study was to determine the effects of wood debris on sediment pore-water hydrogen sulfide concentrations and eelgrass germination. To test the impact of wood inputs on sulfide production and seed germination, we conducted a laboratory mesocosm experiment, adding sawdust to marine sediments and measuring the sulfide levels weekly. We subsequently planted seeds in the mesocosms and measured germination rates. Higher concentrations of sawdust led to higher levels of pore-water hydrogen sulfide and drastically slower eelgrass germination rates. Treatments with greater than 10% wood enrichment developed free sulfide concentrations of 0.815 (± 0.427) mM after 118 days, suggesting sediments with greater than 10% wood pollution may have threateningly high pore-water hydrogen sulfide levels. These results can be used to set thresholds for remediation efforts and guide seed distribution in wood polluted areas.

Functional consortium for denitrifying sulfide removal process.

Science.gov (United States)

Chen, Chuan; Ren, Nanqi; Wang, Aijie; Liu, Lihong; Lee, Duu-Jong

2010-03-01

Denitrifying sulfide removal (DSR) process simultaneously converts sulfide, nitrate, and chemical oxygen demand from industrial wastewaters to elemental sulfur, nitrogen gas, and carbon dioxide, respectively. This investigation utilizes a dilution-to-extinction approach at 10(-2) to 10(-6) dilutions to elucidate the correlation between the composition of the microbial community and the DSR performance. In the original suspension and in 10(-2) dilution, the strains Stenotrophomonas sp., Thauera sp., and Azoarcus sp. are the heterotrophic denitrifiers and the strains Paracoccus sp. and Pseudomonas sp. are the sulfide-oxidizing denitrifers. The 10(-4) dilution is identified as the functional consortium for the present DSR system, which comprises two functional strains, Stenotrophomonas sp. strain Paracoccus sp. At 10(-6) dilution, all DSR performance was lost. The functions of the constituent cells in the DSR granules were discussed based on data obtained using the dilution-to-extinction approach.

Activation mechanism of ammonium ions on sulfidation of malachite (-201) surface by DFT study

Science.gov (United States)

Wu, Dandan; Mao, Yingbo; Deng, Jiushuai; Wen, Shuming

2017-07-01

The activation mechanism of ammonium ions on the sulfidation of malachite (-201) was determined by density functional theory (DFT) calculations. Results of DFT calculations indicated that interlayer sulfidation occurs during the sulfidation process of malachite (-201). The absorption of both the ammonium ion and sulfide ion on the malachite (-201) surface is stronger than that of sulfur ion. After sulfidation was activated with ammonium ion, the Cu 3d orbital peak is closer to the Fermi level and characterized by a stronger peak value. Therefore, the addition of ammonium ions activated the sulfidation of malachite (-201), thereby improving the flotation performance.

Hydrogen sulfide generation in shipboard oily-water waste. Part 3. Ship factors

Energy Technology Data Exchange (ETDEWEB)

Hodgeman, D.K.; Fletcher, L.E.; Upsher, F.J.

1995-04-01

The chemical and microbiological composition of bilge-water in ships of the Royal Australian Navy has been investigated in relation to the formation of hydrogen sulfide by sulfate-reducing bacteria. Sulfate-reducing bacteria were found in most ships in populations up to 800,000 per mL. Sulfate in the wastes is provided by sea-water. Sea-water constitutes up to 60% (median 20%) of the wastes analysed. Evidence for generation of hydrogen sulfide in the ships was found directly as sulfide or indirectly as depressed sulfate concentrations. The low levels of sulfide found in bilge-water from machinery spaces suggested the ventilation systems were effectively removing the gas from the working area. The effect of storage of the wastes under conditions which simulated the oily- water holding tanks of ships were also investigated. Some wastes were found to produce large quantities of hydrogen sulfide on storage. The wastes that failed to produce hydrogen sulfide were investigated to identify any specific nutritional deficiencies. Some organic substances present in bilge-water, such as lactate or biodegradable cleaning agents, and phosphate strongly influenced the generation of hydrogen sulfide in stored oily-water wastes.

Study on the sulfidation behavior of smithsonite

International Nuclear Information System (INIS)

Wu, Dandan; Wen, Shuming; Deng, Jiushuai; Liu, Jian; Mao, Yingbo

2015-01-01

Highlights: • Zeta potential showed that the pH IEP of smithsonite decreased from 7.7 to 6. • ICP test showed the gradual reduction of C S in the solution. • SEM showed that the mineral surface was partially changed to ZnS film. • XPS indicated that the presence of a characteristic signal peak of sulfur ions. - Abstract: Zinc extraction from low-grade mineral resources of oxidized zinc has recently become a focus of study. Sulfidation is an important process in oxidized ore flotation. In this study, the influence of sulfur ion adsorption on smithsonite surface was investigated with the use of zeta potential, inductively coupled plasma (ICP), scanning electron microscope (SEM), and X-ray photoelectron spectroscopic studies. Zeta potential measurements of sodium sulfide showed that sulfur ions were adsorbed onto the surface of pure smithsonite, as evidenced by the increased negative charge and the decrease in the pH IEP of smithsonite from 7.7 to 6 after sodium sulfide treatment. The ICP test revealed the gradual reduction in sulfur ion adsorption onto the surface of smithsonite in pulp sulfur. After 30 min of absorption, C S in the solution declined from 1000 × 10 −6 mol/L to 1.4 × 10 −6 mol/L. SEM results showed that the mineral surface was partially changed to ZnS film after sodium sulfide treatment, whereas EDS analysis results showed that 2% S is contained on the smithsonite surface. X-ray photoelectron spectroscopy results indicated the presence of a characteristic signal peak of sulfur ions after sulfidation. Sulfur concentration increased to 11.89%, whereas oxygen concentration decreased from 42.31% to 13.74%. Sulfur ions were not only present during chemical adsorption, but were also incorporated into the crystal lattices of minerals by the exchange reaction between S 2− and CO 3 2− ions

Metal sulfide electrodes and energy storage devices thereof

Science.gov (United States)

Chiang, Yet-Ming; Woodford, William Henry; Li, Zheng; Carter, W. Craig

2017-02-28

The present invention generally relates to energy storage devices, and to metal sulfide energy storage devices in particular. Some aspects of the invention relate to energy storage devices comprising at least one flowable electrode, wherein the flowable electrode comprises an electroactive metal sulfide material suspended and/or dissolved in a carrier fluid. In some embodiments, the flowable electrode further comprises a plurality of electronically conductive particles suspended and/or dissolved in the carrier fluid, wherein the electronically conductive particles form a percolating conductive network. An energy storage device comprising a flowable electrode comprising a metal sulfide electroactive material and a percolating conductive network may advantageously exhibit, upon reversible cycling, higher energy densities and specific capacities than conventional energy storage devices.

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

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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

Development of novel and sensitive methods for the determination of sulfide in aqueous samples by hydrogen sulfide generation-inductively coupled plasma-atomic emission spectroscopy.

Science.gov (United States)

Colon, M; Todolí, J L; Hidalgo, M; Iglesias, M

2008-02-25

Two new, simple and accurate methods for the determination of sulfide (S(2-)) at low levels (microgL(-1)) in aqueous samples were developed. The generation of hydrogen sulfide (H(2)S) took place in a coil where sulfide reacted with hydrochloric acid. The resulting H(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 180.669nm. In comparison to when aqueous sulfide was introduced, the introduction of sulfur as H(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(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 5microgL(-1) to 25mgL(-1) of sulfide. Detection limits of 5microgL(-1) and 6microgL(-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.

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.

Volcanic sulfur degassing and the role of sulfides in controlling volcanic metal emissions

Science.gov (United States)

Edmonds, M.; Liu, E.

2017-12-01

Volcanoes emit prodigious quantities of sulfur and metals, their behaviour inextricably linked through pre-eruptive sulfide systematics and through degassing and speciation in the volcanic plume. Fundamental differences exist in the metal output of ocean island versus arc volcanoes, with volcanoes in Hawaii and Iceland outgassing large fluxes of gaseous and particulate chalcophiles; and arc volcanoes' plumes, in contrast, enriched in Zn, Cu, Tl and Pb. Metals and metalloids partition into a magmatic vapor phase from silicate melt at crustal pressures. Their abundance in magmatic vapor is influenced strongly by sulfide saturation and by the composition of the magmatic vapor phase, particularly with respect to chloride. These factors are highly dependent on tectonic setting. Metal outgassing is controlled by magma water content and redox: deep saturation in vapor and minimal sulfide in arc basalts yields metal-rich vapor; shallow degassing and resorption of sulfides feeds the metal content of volcanic gas in ocean islands. We present a detailed study of the sulfide systematics of the products of the 2014-2015 Holuhraun basaltic fissure eruption (Bárðarbunga volcanic system, Iceland) to illustrate the interplay between late water and sulfur outgassing; sulfide saturation and breakdown; and metal partitioning into a vapor phase. Sulfide globules, representing quenched droplets of an immiscible sulfide liquid, are preserved within erupted tephra. Sulfide globules in rapidly quenched tephra are preserved within both matrix glass and as inclusions in crystals. The stereologically-corrected 3D size distribution of sulfide globules ranges from importance in supplying sulfur and metals to the atmosphere during eruption.

Nano Transition Metal Sulfide Catalyst for Solvolysis Liquefaction of Soda Lignin

International Nuclear Information System (INIS)

Fei-Ling, P.; Chin-Hua, C.; Sarani Zakaria; Soon-Keong, N.; Tze-Khong, L.

2011-01-01

Solvolysis liquefaction of soda lignin in the presence of various transition metal sulfide catalysts was studied to investigate the catalyst effects on the oil and gas yields, conversion rate and higher heating value (HHV) of oil. Nano sized copper sulfide, iron sulfide and molybdenum sulfide were successfully synthesized via a simple hydrothermal method under reaction temperature 200 degree Celsius for 90 min. The addition of transition metal sulfide based catalysts (CuS, MoS 2 and FeS 2 ) enhanced both production of the oils and gas and the higher heating value (HHV) of oil products. A high oil and gas yields of 82.1 % and 2890 cm 3 was obtained with MoS 2 at 250 degree Celsius for 60 min. Elemental analyses for the oils revealed that the liquid products have much higher heating values than the crude soda lignin powder. (author)

Formation of nanocolloidal metacinnabar in mercury-DOM-sulfide systems

Science.gov (United States)

Gerbig, Chase A.; Kim, Christopher S.; Stegemeier, John P.; Ryan, Joseph N.; Aiken, George R.

2011-01-01

Direct determination of mercury (Hg) speciation in sulfide-containing environments is confounded by low mercury concentrations and poor analytical sensitivity. Here we report the results of experiments designed to assess mercury speciation at environmentally relevant ratios of mercury to dissolved organic matter (DOM) (i.e., structure (EXAFS) spectroscopy. Aqueous Hg(II) and a DOM isolate were equilibrated in the presence and absence of 100 μM total sulfide. In the absence of sulfide, mercury adsorption to the resin increased as the Hg:DOM ratio decreased and as the strength of Hg-DOM binding increased. EXAFS analysis indicated that in the absence of sulfide, mercury bonds with an average of 2.4 ± 0.2 sulfur atoms with a bond length typical of mercury-organic thiol ligands (2.35 Å). In the presence of sulfide, mercury showed greater affinity for the C18 resin, and its chromatographic behavior was independent of Hg:DOM ratio. EXAFS analysis showed mercury–sulfur bonds with a longer interatomic distance (2.51–2.53 Å) similar to the mercury–sulfur bond distance in metacinnabar (2.53 Å) regardless of the Hg:DOM ratio. For all samples containing sulfide, the sulfur coordination number was below the ideal four-coordinate structure of metacinnabar. At a low Hg:DOM ratio where strong binding DOM sites may control mercury speciation (1.9 nmol mg–1) mercury was coordinated by 2.3 ± 0.2 sulfur atoms, and the coordination number rose with increasing Hg:DOM ratio. The less-than-ideal coordination numbers indicate metacinnabar-like species on the nanometer scale, and the positive correlation between Hg:DOM ratio and sulfur coordination number suggests progressively increasing particle size or crystalline order with increasing abundance of mercury with respect to DOM. In DOM-containing sulfidic systems nanocolloidal metacinnabar-like species may form, and these species need to be considered when addressing mercury biogeochemistry.

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

Science.gov (United States)

Chen, Chuan; Ren, Nanqi; Wang, Aijie; Liu, Lihong; Lee, Duu-Jong

2010-07-15

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. 2010 Elsevier B.V. All rights reserved.

Sulfidization of an aluminocobaltomolybdenum catalyst using the 35S radioisotope

International Nuclear Information System (INIS)

Isagulyants, G.V.; Greish, A.A.; Kogan, V.M.

1987-01-01

It has been established that in aluminocobaltomolybdenum catalyst sulfidized with elemental sulfur there are two types of sulfur, free and bound. The maximum amount of bound sulfur in ACM catalyst is 6.6 wt. %, which corresponds to practically complete sulfidation of the ACM catalyst. In the presence of hydrogen an equilibrium distribution of bound sulfur is achieved in a granule of ACM catalyst irrespective of the temperature of sulfidation. In a nitrogen atmosphere it is primarily the surface layers of the catalyst that are sulfured

Microbial selenium sulfide reduction for selenium recovery from wastewater

NARCIS (Netherlands)

Hageman, S.P.W.; Weijden, van der R.D.; Stams, A.J.M.; Cappellen, van P.; Buisman, C.J.N.

2017-01-01

Microbial reduction of selenium sulfide (SeS2) is a key step in a new treatment process to recover selenium from selenate and selenite streams. In this process, selenate is first reduced to selenite, and subsequently selenite is reduced by sulfide and precipitates from the solution as SeS2. The

Study on the surface sulfidization behavior of smithsonite at high temperature

Science.gov (United States)

Lv, Jin-fang; Tong, Xiong; Zheng, Yong-xing; Xie, Xian; Wang, Cong-bing

2018-04-01

Surface sulfidization behavior of smithsonite at high temperature was investigated by X-ray powder diffractometer (XRD) along with thermodynamic calculation, X-ray photoelectron spectroscopy (XPS) and electron probe microanalysis (EPMA). The XRD and thermodynamic analyses indicated that the smithsonite was decomposed into zincite at high temperatures. After introducing a small amount of pyrite, artificial sulfides were formed at surface of the obtained zincite. The XPS analyses revealed that the sulfide species including zinc sulfide and zinc disulfide were generated at the zincite surface. The EPMA analyses demonstrated that the film of sulfides was unevenly distributed at the zincite surface. The average concentration of elemental sulfur at the sample surface increased with increasing of pyrite dosage. A suitable mole ratio of FeS2 to ZnCO3 for the surface thermal modification was determined to be about 0.3. These findings can provide theoretical support for improving the process during which the zinc recovery from refractory zinc oxide ores is achieved by xanthate flotation.

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.

Toxicity of sulfide to early life stages of wild rice (Zizania palustris).

Science.gov (United States)

Fort, Douglas J; Todhunter, Kevin; Fort, Troy D; Mathis, Michael B; Walker, Rachel; Hansel, Mike; Hall, Scott; Richards, Robin; Anderson, Kurt

2017-08-01

The sensitivity of wild rice (Zizania palustris) to sulfide is not well understood. Because sulfate in surface waters is reduced to sulfide by anaerobic bacteria in sediments and historical information indicated that 10 mg/L sulfate in Minnesota (USA) surface water reduced Z. palustris abundance, the Minnesota Pollution Control Agency established 10 mg/L sulfate as a water quality criterion in 1973. A 21-d daily-renewal hydroponic study was conducted to evaluate sulfide toxicity to wild rice and the potential mitigation of sulfide toxicity by iron (Fe). The hydroponic design used hypoxic test media for seed and root exposure and aerobic headspace for the vegetative portion of the plant. Test concentrations were 0.3, 1.6, 3.1, 7.8, and 12.5 mg/L sulfide in test media with 0.8, 2.8, and 10.8 mg/L total Fe used to evaluate the impact of iron on sulfide toxicity. Visual assessments (i.e., no plants harvested) of seed activation, mesocotyl emergence, seedling survival, and phytoxicity were conducted 10 d after dark-phase exposure. Each treatment was also evaluated for time to 30% emergence (ET30), total plant biomass, root and shoot lengths, and signs of phytotoxicity at study conclusion (21 d). The results indicate that exposure of developing wild rice to sulfide at ≥3.1 mg sulfide/L in the presence of 0.8 mg/L Fe reduced mesocotyl emergence. Sulfide toxicity was mitigated by the addition of Fe at 2.8 mg/L and 10.8 mg/L relative to the control value of 0.8 mg Fe/L, demonstrating the importance of iron in mitigating sulfide toxicity to wild rice. Ultimately, determination of site-specific sulfate criteria taking into account factors that alter toxicity, including sediment Fe and organic carbon, are necessary. Environ Toxicol Chem 2017;36:2217-2226. © 2017 SETAC. © 2017 SETAC.

Sulfide phase in the Fe-Ti-S and Fe-C-Ti-S alloys

International Nuclear Information System (INIS)

Malinochka, Ya.N.; Balakina, N.A.; Shmelev, Yu.S.

1976-01-01

The nature of the sulfide phases in Fe-Ti-S and Fe-C-Ti-S alloys was studied. The carbide and the sulfide phase were identified the aid of X-ray spectral microanalysis. It was established that for a small content of titanium and sulfur in ternary Fe-Ti-S alloys the solidification of the γ-solution on the boundaries of dendritic branches is accompanied, along with the precipitation of a sulfide rich in iron of the (Fe, Ti) S type where a small quantity of titanium is dissolved, by the formation of a titanium-bearing sulfide eutectic γ + TiS. The amount of the sulfide eutectic increases with the contents of titanium and sulfur until a purely eutectic alloy is formed. Both carbides and sulfides may be formed in the solidification of quaternary alloys Fe-C-Ti-S

Preparation and characterization of amorphous manganese sulfide thin films by SILAR method

International Nuclear Information System (INIS)

Pathan, H.M.; Kale, S.S.; Lokhande, C.D.; Han, Sung-Hwan; Joo, Oh-Shim

2007-01-01

Manganese sulfide thin films were deposited by a simple and inexpensive successive ionic layer adsorption and reaction (SILAR) method using manganese acetate as a manganese and sodium sulfide as sulfide ion sources, respectively. Manganese sulfide films were characterized for their structural, surface morphological and optical properties by means of X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis and optical absorption measurement techniques. The as-deposited film on glass substrate was amorphous. The optical band gap of the film was found to be thickness dependent. As thickness increases optical band gap was found to be increase. The water angle contact was found to be 34 o , suggesting hydrophilic nature of manganese sulfide thin films. The presence of Mn and S in thin film was confirmed by energy dispersive X-ray analysis

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

Science.gov (United States)

2011-10-17

... Hydrogen Sulfide; Community Right-to-Know Toxic Chemical Release Reporting AGENCY: Environmental Protection Agency (EPA). ACTION: Lifting of Administrative Stay for Hydrogen Sulfide. SUMMARY: EPA is announcing... (EPCRA) section 313 toxic chemical release reporting requirements for hydrogen sulfide (Chemical...

76 FR 69136 - Hydrogen Sulfide; Community Right-to-Know Toxic Chemical Release Reporting

Science.gov (United States)

2011-11-08

... Hydrogen Sulfide; Community Right-to-Know Toxic Chemical Release Reporting AGENCY: Environmental Protection Agency (EPA). ACTION: Lifting of Administrative Stay for Hydrogen Sulfide; Correction. SUMMARY: The... Administrative Stay of the reporting requirements for hydrogen sulfide. The Office of the Federal Register...

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

International Nuclear Information System (INIS)

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

2016-01-01

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. - Highlights: • A sulfide-oxidizing microbiota successfully enriched from aquaculture sediment. • Microbiota dominated by Vibrio, Marinobacter, Pseudomonas and Thiobacillus spp. • Sulfide-oxidizing microbiota removed sulfide at an average rate of 100 mg/(L·h). • Immobilized microbiota removed over 85% of sulfide even recycled for five times.

Influence of pipe material and surfaces on sulfide related odor and corrosion in sewers.

Science.gov (United States)

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

2008-09-01

Hydrogen sulfide oxidation on sewer pipe surfaces was investigated in a pilot scale experimental setup. The experiments were aimed at replicating conditions in a gravity sewer located immediately downstream of a force main where sulfide related concrete corrosion and odor is often observed. During the experiments, hydrogen sulfide gas was injected intermittently into the headspace of partially filled concrete and plastic (PVC and HDPE) sewer pipes in concentrations of approximately 1,000 ppm(v). Between each injection, the hydrogen sulfide concentration was monitored while it decreased because of adsorption and subsequent oxidation on the pipe surfaces. The experiments showed that the rate of hydrogen sulfide oxidation was approximately two orders of magnitude faster on the concrete pipe surfaces than on the plastic pipe surfaces. Removal of the layer of reaction (corrosion) products from the concrete pipes was found to reduce the rate of hydrogen sulfide oxidation significantly. However, the rate of sulfide oxidation was restored to its background level within 10-20 days. A similar treatment had no observable effect on hydrogen sulfide removal in the plastic pipe reactors. The experimental results were used to model hydrogen sulfide oxidation under field conditions. This showed that the gas-phase hydrogen sulfide concentration in concrete sewers would typically amount to a few percent of the equilibrium concentration calculated from Henry's law. In the plastic pipe sewers, significantly higher concentrations were predicted because of the slower adsorption and oxidation kinetics on such surfaces.

Dual responsive dysprosium-doped hydroxyapatite particles and toxicity reduction after functionalization with folic and glucuronic acids.

Science.gov (United States)

Sánchez Lafarga, Ana Karen; Pacheco Moisés, Fermín P; Gurinov, Andrey; Ortiz, Genaro Gabriel; Carbajal Arízaga, Gregorio Guadalupe

2015-03-01

The development of probes for biomedical applications demands materials with low toxicity levels besides fluorescence or magnetic properties to be detected by confocal microscopes or MRI resonators. Several drug delivery systems or other biomedical materials prepared with hydroxyapatite have been proposed, however, toxicity effects might arise when the size of particles is nanometric. In this study, hydroxyapatite functionalized with glucuronic or folic acids presented lower oxidative stress, measured from lipoperoxides and nitric oxide indicators in rats than pure hydroxyapatite. In separated experiments, hydroxyapatite was doped with dysprosium cations by coprecipitation producing a single crystal phase with fluorescent properties easily visualized by confocal microscopy when excited at 488nm. These particles also presented the ability to modify the proton relaxation time in T1 maps collected by magnetic resonance imaging. These modified hydroxyapatite nanoparticles could be candidates to design bimodal probes with low toxicity. Copyright © 2014 Elsevier B.V. All rights reserved.

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.; 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.

Alkaline sulfide pretreatment of an antimonial refractory Au-Ag ore for improved cyanidation

Science.gov (United States)

Alp, Ibrahim; Celep, Oktay; Deveci, Haci

2010-11-01

This paper presents the alkaline sulfide pretreatment of an antimonial refractory gold and silver ore. In the ore, gold occurs mainly as gold-silver alloys and as associated with quartz and framboidal pyrite grains, and, to a small extent, as the inclusions within antimonial sulfides. Silver is present extensively as antimonial sulfides such as andorite. Alkaline sulfide pretreatment was shown to allow the decomposition of the antimonial sulfide minerals (up to 98% Sb removal) and to remarkably improve the amenability of gold (e.g., from leaching. An increase in reagent concentration (1-4 mol/L Na2S or NaOH) and temperature (20-80°C), and a decrease in particle size seem to produce an enhancing effect on metal extraction. These findings suggest that alkaline sulfide leaching can be suitably used as a chemical pretreatment method prior to the conventional cyanidation for antimonial refractory gold and silver ores.

The Complex Resistivity Spectrum Characteristics About Stratabound Sulfide Deposits

Science.gov (United States)

Dong, P.; Sun, B.; Wang, L.; Chen, Z.; Dong, Z.; Wu, Y.

2010-12-01

Complex resistivity method has become the key technique of deep prospecting, and widely applied in stratabound sulfide deposits which often form massive ores. However, the complex resistivity spectrum characteristics of stratabound sulfide deposits remains unknown. Through studying variation problem of two-dimensional polarization medium, deducing the differential equations and calculating formula,we applied Cole-Cole model to deduce the spectrum of complex resistivity based on the model of three-node and four-node finite element method, and programmed homologous procedure. We utilized the Earth Model of Geological Layers which has accurate analytical solution to test rationality and accuracy of our modeling. We applied the layer structure provided by drilling results in Chenmenshan copper mine,which is typical strata-bound sulfide deposits in Jiangxi province,China, and calculated the spectra of complex resistivity, then made comparison between modeled and measured values. We find good corellation between them. Our studies may have imporved the interpretation of complex resistivity data, which help apply complex resistivity methods of propecting on stratabound sulfide deposites.

Hydrogen sulfide waste treatment by microwave plasma-chemistry

Energy Technology Data Exchange (ETDEWEB)

Harkness, J.B.L.; Doctor, R.D.

1994-03-01

A waste-treatment process that recovers both hydrogen and sulfur from industrial acid-gas waste streams is being developed to replace the Claus technology, which recovers only sulfur. The proposed process is derived from research reported in the Soviet technical literature and uses microwave (or radio-frequency) energy to initiate plasma-chemical reactions that dissociate hydrogen sulfide into elemental hydrogen and sulfur. This process has several advantages over the current Claus-plus-tail-gas-cleanup technology, which burns the hydrogen to water. The primary advantage of the proposal process is its potential for recovering and recycling hydrogen more cheaply than the direct production of hydrogen. Since unconverted hydrogen sulfide is recycled to the plasma reactor, the plasma-chemical process has the potential for sulfur recoveries in excess of 99% without the additional complexity of the tail-gas-cleanup processes associated with the Claus technology. There may also be some environmental advantages to the plasma-chemical process, because the process purge stream would primarily be the carbon dioxide and water contained in the acid-gas waste stream. Laboratory experiments with pure hydrogen sulfide have demonstrated the ability of the process to operate at or above atmospheric pressure with an acceptable hydrogen sulfide dissociation energy. Experiments with a wide range of acid-gas compositions have demonstrated that carbon dioxide and water are compatible with the plasma-chemical dissociation process and that they do not appear to create new waste-treatment problems. However, carbon dioxide does have negative impacts on the overall process. First, it decreases the hydrogen production, and second, it increases the hydrogen sulfide dissociation energy.

Separation of platinum metals by theirs extraction as sulfides

International Nuclear Information System (INIS)

Pilipenko, A.T.; Ryabushko, O.P.; Ty Van Mak

1978-01-01

Separation of platinum metals by means of their sediment in the form of sulfides with subsequent extraction is studied. The optimum conditions of metal sulfide extraction are determined, the metal output dependence from acidness and aqueous phase composition and also the organic solvent nature are investigated. Ruthenium concentration was determined photometrically. Ruthenium sulfide is extracted by butyl spirit from 1-4 normal hydrochloric acid. The maximum extraction grade of 63% is reached in 3.2-normal acid. When the mixture of acetic and hydrochloric acids (2:1) is used for decomposition of ruthenium tiosalts, the grade of ruthenium extraction by amyl spirit or the mixture of anyl and butyl spirits (1:1) constitutes 100%

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

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

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......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...

Exploration of dysprosium: the most critical element for Japan

Science.gov (United States)

Watanabe, Y.

2012-04-01

Dysprosium (Dy), one of the heavy rare earth elements, is used mainly as an additive for NdFeB permanent magnets which are installed in various modern industrial products such as voice coil motors in computers, factory automation machinery, hybrid and electric vehicles, home electronics, and wind turbine, to improve heat resistance of the magnets. Dy has been produced about 2,000t per year from the ores from ion adsorption type deposits in southern China. However, the produced amount of Dy was significantly reduced in 2011 in China due to reservation of heavy rare earth resources and protection of natural environment, resulting in soaring of Dy price in the world. In order to respond the increasing demand of Dy, unconventional supply sources are inevitably developed, in addition to heavy rare earth enriched ion adsorption type deposits outside China. Heavy rare earth elements including Dy are dominantly hosted in xenotime, fergusonite, zircon, eudialyte, keiviite, kainosite, iimoriite, etc. Concentration of xenotime is found in placer deposits in Malaysia and India, hydrothermal deposits associated with unconformity-type uranium mineralization (Athabasca basin in Canada, Western Australia), iron-oxide fluorite mineralization (South Africa) and Sn-bearing alkaline granite (Brazil). Zircon and fergusontie concentration is found as igneous and hydrothermal products in peralkaline syenite, alkaline granite and pegmatite (e.g., Nechalacho in Canada). Eudialyte concentration is found in some peralkaline syenite bodies in Greenland, Canada, Sweden and Russia. Among these sources, large Dy resources are estimated in the deposits hosted in peralkaline rocks (Nechalacho: 79,000t, Kvanefjeld: 49,000t, Norra Karr: 15,700t, etc.) compared to the present demand of Dy. Thus, Dy will be supplied from the deposits associated with peralkaline and alkaline deposits in future instead of ion adsorption type deposits in southern China.

Study of radiation synovectomy using 188Re-sulfide

International Nuclear Information System (INIS)

Chen Gang; Li Peiyong; Jiang Xufeng; Zhang Liying; Wang Xuefeng; Sun Zhenming; Zhang Huan

2002-01-01

Objective: To study the radiation synovectomy with 188 Re-sulfide. Methods: Thirty cases were divided into 2 groups, the group with hemophilia and the group with rheumatoid arthritis (RA). Patients with joint synovitis were injected different doses of 188 Re-sulfide, 222 - 444 MBq intra-articular. MRI was taken before and 3 - 6 months after the radiation synovectomy to evaluate the treatment efficacy, and the symptoms were also evaluated. Results: MRI study showed that after the treatment the synovium became thiner and the edema was reduced in the lesioned joint. The symptoms were improved with the pain relieved and duration of intra-articular hemorrhage reduced. Conclusions: Radiation synovectomy using 188 Re-sulfide has effects on synovitis. It can be used clinically to improve the symptoms of joint synovitis and reduce the duration of intra-articular hemorrhage

Study on the sulfidation behavior of smithsonite

Energy Technology Data Exchange (ETDEWEB)

Wu, Dandan; Wen, Shuming, E-mail: shmwen@126.com; Deng, Jiushuai, E-mail: dengshuai689@163.com; Liu, Jian; Mao, Yingbo

2015-02-28

Highlights: • Zeta potential showed that the pH{sub IEP} of smithsonite decreased from 7.7 to 6. • ICP test showed the gradual reduction of C{sub S} in the solution. • SEM showed that the mineral surface was partially changed to ZnS film. • XPS indicated that the presence of a characteristic signal peak of sulfur ions. - Abstract: Zinc extraction from low-grade mineral resources of oxidized zinc has recently become a focus of study. Sulfidation is an important process in oxidized ore flotation. In this study, the influence of sulfur ion adsorption on smithsonite surface was investigated with the use of zeta potential, inductively coupled plasma (ICP), scanning electron microscope (SEM), and X-ray photoelectron spectroscopic studies. Zeta potential measurements of sodium sulfide showed that sulfur ions were adsorbed onto the surface of pure smithsonite, as evidenced by the increased negative charge and the decrease in the pH{sub IEP} of smithsonite from 7.7 to 6 after sodium sulfide treatment. The ICP test revealed the gradual reduction in sulfur ion adsorption onto the surface of smithsonite in pulp sulfur. After 30 min of absorption, C{sub S} in the solution declined from 1000 × 10{sup −6} mol/L to 1.4 × 10{sup −6} mol/L. SEM results showed that the mineral surface was partially changed to ZnS film after sodium sulfide treatment, whereas EDS analysis results showed that 2% S is contained on the smithsonite surface. X-ray photoelectron spectroscopy results indicated the presence of a characteristic signal peak of sulfur ions after sulfidation. Sulfur concentration increased to 11.89%, whereas oxygen concentration decreased from 42.31% to 13.74%. Sulfur ions were not only present during chemical adsorption, but were also incorporated into the crystal lattices of minerals by the exchange reaction between S{sup 2−} and CO{sub 3}{sup 2−} ions.

Effects of sulfide treatment on electronic transport of graphene/n-type Si Schottky diodes

Energy Technology Data Exchange (ETDEWEB)

Zeng, Jian-Jhou; Lin, Yow-Jon, E-mail: rzr2390@yahoo.com.tw

2014-05-01

The present work reports the fabrication and detailed electrical properties of graphene/n-type Si Schottky diodes with and without sulfide treatment. The graphene/n-type Si Schottky diode without sulfide treatment shows a poor rectifying behavior with an ideality factor (η) of 4.2 and high leakage. η > 2 implies that the interfacial defects influence the electronic conduction through the device. However, the graphene/n-type Si Schottky diode with sulfide treatment for 5 min shows a good rectifying behavior with η of 1.8 and low leakage. Such an improvement indicates that a good passivation is formed at the interface as a result of the reduction of the defect density. These experimental demonstrations suggest that it may be possible to minimize the adverse effects of the interface states to obtain functional devices using sulfide treatment. In addition, the graphene/n-type Si Schottky diode with sulfide treatment for 10 min shows a poor rectifying behavior with η of 2.5 and high leakage. Note, a suitable sulfide treatment time is an important issue for improving the device performance. - Highlights: • Graphene/Si diodes with sulfide treatment for 5 min show a good rectifying behavior. • Graphene/Si diodes without sulfide treatment show a poor rectifying behavior. • The interfacial defects of Schottky diodes were controlled by sulfide treatment. • Such an improvement indicates that a good passivation is formed at the interface. • A suitable sulfide treatment time is an important issue for improving performances.

Effects of sulfide treatment on electronic transport of graphene/n-type Si Schottky diodes

International Nuclear Information System (INIS)

Zeng, Jian-Jhou; Lin, Yow-Jon

2014-01-01

The present work reports the fabrication and detailed electrical properties of graphene/n-type Si Schottky diodes with and without sulfide treatment. The graphene/n-type Si Schottky diode without sulfide treatment shows a poor rectifying behavior with an ideality factor (η) of 4.2 and high leakage. η > 2 implies that the interfacial defects influence the electronic conduction through the device. However, the graphene/n-type Si Schottky diode with sulfide treatment for 5 min shows a good rectifying behavior with η of 1.8 and low leakage. Such an improvement indicates that a good passivation is formed at the interface as a result of the reduction of the defect density. These experimental demonstrations suggest that it may be possible to minimize the adverse effects of the interface states to obtain functional devices using sulfide treatment. In addition, the graphene/n-type Si Schottky diode with sulfide treatment for 10 min shows a poor rectifying behavior with η of 2.5 and high leakage. Note, a suitable sulfide treatment time is an important issue for improving the device performance. - Highlights: • Graphene/Si diodes with sulfide treatment for 5 min show a good rectifying behavior. • Graphene/Si diodes without sulfide treatment show a poor rectifying behavior. • The interfacial defects of Schottky diodes were controlled by sulfide treatment. • Such an improvement indicates that a good passivation is formed at the interface. • A suitable sulfide treatment time is an important issue for improving performances

Sulfide Species Optical Monitoring by a Miniaturized Silicon Photomultiplier

Directory of Open Access Journals (Sweden)

Salvatore Petralia

2018-02-01

Full Text Available The monitoring of water-soluble pollutants is receiving a growing interest from the scientific community. In this context, sulfide anion species S2− and HS− are particularly relevant since they can cause acute and chronic toxicity including neurological effects and at high concentrations, even death. In this study, a new strategy for fast and sensitive optical detection of sulfide species in water samples is described. The method uses an integrated silicon photomultiplier (SiPM device coupled with the appropriate analytical strategy applied in a plastic microchip with dried reagents on board. More specifically, all sulfide species (H2S, HS− and S2− in water samples are detected by the fluorescence signal emitted upon the reaction with N,N-dimethyl-phenylenediamine sulfate in the presence of Fe3+, leading to the formation of the fluorescent methylene blue (MB species. It has been proven that the system herein proposed is able to measure sulfide concentration in a linear range from 0–10 mg L−1 with a sensitivity value of about 6.7 µA mg−1 L and a detection limit of 0.5 mg L−1. A comparison with conventional UV-Vis detection method has been also carried out. Data show a very good linear correlation (R2 = 0.98093, proving the effectiveness of the method. Results pave the way toward the development of portable and low-cost device systems for water-soluble sulfide pollutants.

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

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...

Sorption of chromium(III) and chromium(VI) on lead sulfide

International Nuclear Information System (INIS)

Music, S.

1985-01-01

The sorption of chromium(III) and chromium(VI) on lead sulfide was investigated in dependence on pH, time of sorption, and on the concnetrations of sorbate and sorbent. The mechanisms of the sorption of Crsup(3+) and CrOsub(4)sup(2-) traces on lead sulfide are discussed; a difference between CrOsub(4)sup(2-) sorption on PbS and α-Fesub(2)Osub(3) was found. Sulfates and molybdates affect the removal of chromates from aqueous solutions. Lead sulfide carrier prepared in this work was also used for the preconcentration of chromium(III) and chromium(VI) from tap water. (author)

Isolation of {sup 163}Ho from dysprosium target material by HPLC for neutrino mass measurements

Energy Technology Data Exchange (ETDEWEB)

Mocko, Veronika; Taylor, Wayne A.; Nortier, Francois M.; Engle, Jonathan W.; Pollington, Anthony D.; Kunde, Gerd J.; Rabin, Michael W.; Birnbaum, Eva R. [Los Alamos National Laboratory, Los Alamos, NM (United States). Chemistry Div.; Barnhart, Todd E.; Nickles, Robert J. [Univ. Wisconsinn, Madison, WI (United States). Dept. of Medical Physics

2015-07-01

The rare earth isotope {sup 163}Ho is of interest for neutrino mass measurements. This report describes the isolation of {sup 163}Ho from a proton-irradiated dysprosium target and its purification. A Dy metal target was irradiated with 16 MeV protons for 10 h. After target dissolution, {sup 163}Ho was separated from the bulk Dy via cation-exchange high performance liquid chromatography using 70 mmol dm{sup -3} α-hydroxyisobutyric acid as the mobile phase. Subsequent purification of the collected Ho fraction was performed to remove the α-hydroxyisobutyrate chelating agent and to concentrate the Ho in a low ionic strength aqueous matrix. The final solution was characterized by MC-ICP-MS to determine the {sup 163}Ho/{sup 165}Ho ratio, {sup 163}Ho and the residual Dy content. The HPLC purification process resulted in a decontamination factor 1.4 x 10{sup 5} for Dy. The isolated Ho fraction contained 24.8 ± 1.3 ng of {sup 163}Ho corresponding to holmium recovery of 72 ± 3%.

Benzothiazole sulfide compatibilized polypropylene/halloysite nanotubes composites

Energy Technology Data Exchange (ETDEWEB)

Liu Mingxian [Department of Polymer Materials and Engineering, South China University of Technology, Guangzhou 510640 (China); Guo Baochun, E-mail: psbcguo@scut.edu.cn [Department of Polymer Materials and Engineering, South China University of Technology, Guangzhou 510640 (China); Lei Yanda; Du Mingliang; Jia Demin [Department of Polymer Materials and Engineering, South China University of Technology, Guangzhou 510640 (China)

2009-02-15

Clay-philic benzothiazole sulfide, capable of donating electrons, is grafted onto polypropylene (PP) backbones when N-cyclohexyl-2-benzothiazole sulfonamide (CBS), a commonly used accelerator in the tire industry, is included in the processing of PP/halloysite nanotubes (HNTs) composites. CBS decomposes at elevated temperature and yields benzothiazole sulfide radicals, which react with the PP polymeric free radicals generated during the processing of the composites. On the other hand, the benzothiazole group of CBS is reactive to HNTs via electron transferring. The compatibilization between HNTs and PP is thus realized via interfacial grafting and electron transferring mechanism. The interfacial interactions in the compatibilized systems were fully characterized. Compared with the control sample, the dispersion of HNTs and the interfacial bonding are enhanced substantially in the compatibilized composites. The significantly improved mechanical properties and thermal properties of benzothiazole sulfide compatibilized PP/HNTs composites are correlated to the enhanced interfacial property. The present work demonstrates a novel interfacial design via interfacial grafting/electron transferring for the compatibilization of PP/clay composites.

Global use structures of the magnetic materials neodymium and dysprosium. A scenario-based analysis of the effect of the diffusion of electromobility on the demand for rare earths

International Nuclear Information System (INIS)

Gloeser-Chahoud, Simon; Kuehn, Andre; Tercero Espinoza, Luis

2016-01-01

Neodymium-iron-boron magnets (NdFeB) have experienced a significant demand as the most powerful permanent magnet in recent years, especially for the manufacture of compact electric servomotors with high efficiency and high power density, especially for mobile applications in hybrid traction motors and electric vehicles or for electric bikes. However, NdFeB magnets are also increasingly being used in general mechanical engineering (conveying and pumping systems, tools, air conditioning systems, lift motors, etc.), in the small electric motors of conventional passenger cars or in the generators of large wind power plants with permanent magnetic direct drive. Nevertheless, there is still high uncertainty in the use structures of NdFeB magnets and the contained rare earth elements neodymium and dysprosium. An effective instrument for increasing the market transparency and the understanding of complex anthropogenic material cycles is the dynamic material flow modeling. In the present work paper, this instrument is used for an in-depth analysis of the use structures of NdFeB magnets and the contained rare earths on a global scale. The dynamic modeling of product usage cycles reveals today's usage structures and quantifies future magnetic quantities in obsolete product flows. It could be shown that the magnets in today's scrap volume are mainly contained in obsolete electronics applications such as hard disks (HDD), CD and DVD drives, which makes the recycling hardly seem to be economical due to the small magnets and the high material spread, but in the foreseeable future with larger magnetic quantities from synchronous servomotors and generators can be expected, which significantly increases the recycling potential. In a further step, the effect of the diffusion of alternative drives in the automotive market on the dysprosium requirement is analyzed using a system dynamics model and possible adaptation mechanisms in the form of different substitution effects in the

Using a portable sulfide monitor as a motivational tool: a clinical study.

Science.gov (United States)

Uppal, Ranjit Singh; Malhotra, Ranjan; Grover, Vishakha; Grover, Deepak

2012-01-01

Bad breath has a significant impact on daily life of those who suffer from it. Oral malodor may rank only behind dental caries and periodontal disease as the cause of patient's visit to dentist. An aim of this study was to use a portable sulfide monitor as a motivational tool for encouraging the patients towards the better oral hygiene by correlating the plaque scores with sulfide monitor scores, and comparing the sulfide monitor scores before and after complete prophylaxis and 3 months after patient motivation. 30 patients with chronic periodontitis, having chief complaint of oral malodor participated in this study. At first visit, the plaque scores (P1) and sulfide monitor scores before (BCR1) and after complete oral prophylaxis (BCR2) were taken. Then the patients were motivated towards the better oral hygiene. After 3 months, plaque scores (P2) and sulfide monitor scores (BCR3) were recorded again. It was done using SPSS (student package software for statistical analysis). Paired sample test was performed. Statistically significant reduction in sulfide monitor scores was reported after the complete oral prophylaxis and 3 months after patient motivation. Plaque scores were significantly reduced after a period of 3 months. Plaque scores and breathchecker scores were positively correlated. An intensity of the oral malodor was positively correlated with the plaque scores. The portable sulfide monitor was efficacious in motivating the patients towards the better oral hygiene.

Hydrotreatment of heavy oil from coal liquefaction on Sulfide Ni - W Catalysts

International Nuclear Information System (INIS)

Zhi-ping Lei; Li-juan Gao; Heng-fu Shui; Shi-biao, Ren; Zhi-cai Wang; Kang-shi Gang

2011-01-01

Heavy oil (distillation temperature: 320-340 deg C) derived from the direct coal liquefaction process using Shengli coal were hydrotreated using sulfided Ni-Mo/Al 2 O 3 , Ni-W/Al 2 O 3 , and Ni-W/SiO 2 catalysts respectively. The sulfided catalysts were characterized by BET, XRD, H 2 -TPR and NH 3 -TPD respectively. The evaluations of the hydrodenitrogenation (HDN) and hydrodearomatization (HDA) properties of heavy oil on the three catalysts were carried out at 400 deg C and 5.0 MPa initial H2 pressure. The W-based catalysts displayed better performances than Mo-based catalysts for the HDN and HDA reactions. Al 2 O 3 supported catalysts were found to have higher catalytic activities than on SiO 2 supported ones. The activities of sulfided catalysts were associated mainly with the nature of active sites, acidity, metal sulfide crystallite size and the amount of the reducible sulfur species of metal sulfide. (author)

Crossett Hydrogen Sulfide Air Sampling Report

Science.gov (United States)

This report summarizes the results of the EPA’s hydrogen sulfide air monitoring conducted along Georgia Pacific’s wastewater treatment system and in surrounding Crossett, AR, neighborhoods in 2017.

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

Sulfidation treatment of copper-containing plating sludge towards copper resource recovery.

Science.gov (United States)

Kuchar, D; Fukuta, T; Onyango, M S; Matsuda, H

2006-11-02

The present study is concerned with the sulfidation treatment of copper-containing plating sludge towards copper resource recovery by flotation of copper sulfide from treated sludge. The sulfidation treatment was carried out by contacting simulated or real copper plating sludge with Na(2)S solution for a period of 5 min to 24 h. The initial molar ratio of S(2-) to Cu(2+) (S(2-) to Me(2+) in the case of real sludge) was adjusted to 1.00, 1.25 or 1.50, while the solid to liquid ratio was set at 1:50. As a result, it was found that copper compounds were converted to various copper sulfides within the first 5 min. In the case of simulated copper sludge, CuS was identified as the main sulfidation product at the molar ratio of S(2-) to Cu(2+) of 1.00, while Cu(7)S(4) (Roxbyite) was mainly found at the molar ratios of S(2-) to Cu(2+) of 1.50 and 1.25. Based on the measurements of oxidation-reduction potential, the formation of either CuS or Cu(7)S(4) at different S(2-) to Cu(2+) molar ratios was attributed to the changes in the oxidation-reduction potential. By contrast, in the case of sulfidation treatment of real copper sludge, CuS was predominantly formed, irrespective of S(2-) to Me(2+) molar ratio.

Energy metabolism and metabolomics response of Pacific white shrimp Litopenaeus vannamei to sulfide toxicity.

Science.gov (United States)

Li, Tongyu; Li, Erchao; Suo, Yantong; Xu, Zhixin; Jia, Yongyi; Qin, Jian G; Chen, Liqiao; Gu, Zhimin

2017-02-01

The toxicity and poisoning mechanisms of sulfide were studied in Litopenaeus vannamei from the perspective of energy metabolism and metabolomics. The lethal concentrations of sulfide in L. vannamei (LC50) at 24h, 48h, 72h, and 96h were determined. Sulfide at a concentration of 0, 1/10 (425.5μg/L), and 1/5 (851μg/L) of the LC 50 at 96h was used to test the metabolic responses of L. vannamei for 21days. The chronic exposure of shrimp to a higher sulfide concentration of 851μg/L decreased shrimp survival but did not affect weight gain or the hepatopancreas index. The glycogen content in the hepatopancreas and muscle and the activity of hepatopancreas cytochrome C oxidase of the shrimp exposed to all sulfide concentrations were significantly lower, and the serum glucose and lactic acid levels and lactic acid dehydrogenase activity were significantly lower than those in the control. Metabolomics assays showed that shrimp exposed to sulfide had lower amounts of serum pyruvic acid, succinic acid, glycine, alanine, and proline in the 425.5μg/L group and phosphate, succinic acid, beta-alanine, serine, and l-histidine in the 851μg/L group than in the control. Chronic sulfide exposure could disturb protein synthesis in shrimp but enhance gluconeogenesis and substrate absorption for ATP synthesis and tricarboxylic acid cycles to provide extra energy to cope with sulfide stress. Chronic sulfide exposure could adversely affect the health status of L. vannamei, as indicated by the high amounts of serum n-ethylmaleamic acid, pyroglutamic acid, aspartic acid and phenylalanine relative to the control. This study indicates that chronic exposure of shrimp to sulfide can decrease health and lower survival through functional changes in gluconeogenesis, protein synthesis and energy metabolism. Copyright © 2016 Elsevier B.V. All rights reserved.

Hydrogen sulfide production and volatilization in a polymictic eutrophic saline lake, Salton Sea, California.

Science.gov (United States)

Reese, Brandi Kiel; Anderson, Michael A; Amrhein, Christopher

2008-11-15

The Salton Sea is a large shallow saline lake located in southern California that is noted for high sulfate concentrations, substantial algal productivity, and very warm water column temperatures. These conditions are well-suited for sulfide production, and sulfide has been implicated in summer fish kills, although no studies have been conducted to specifically understand hydrogen sulfide production and volatilization there. Despite polymictic mixing patterns and relatively short accumulation periods, the amount of sulfide produced is comparable to meromictic lakes. Sulfide levels in the Salton Sea reached concentrations of 1.2 mmol L(-1) of total free sulfide in the hypolimnion and 5.6 mmol L(-1) in the sediment pore water. Strong winds in late July mixed H2S into the surface water, where it depleted the entire water column of dissolved oxygen and reached a concentration of 0.1 mmol L(-1). Sulfide concentrations exceeded the toxicity threshold of tilapia (Oreochromis mossambicus) and combined with strong anoxia throughout the water column, resulted in a massive fish kill. The mixing of sulfide into the surface waters also increased atmospheric H2S concentrations, reaching 1.0 micromol m(-3). The flux of sulfide from the sediment into the water column was estimated to range from 2-3 mmol m(-2) day(-1) during the winter and up to 8 mmol m(-2) day(-1) during the summer. Application of the two-layer model for volatilization indicates that up to 19 mmol m(-2) day(-1) volatilized from the surface during the mixing event. We estimate that as much as 3400 Mg year(-1) or approximately 26% of sulfide that diffused into the water column from the deepest sediments may have been volatilized to the atmosphere.

Interaction distances in oxides, sulfides and selenides with face-centered packing

International Nuclear Information System (INIS)

Kesler, Ya.A.

1993-01-01

Concept of characteristic distances (CD) was specified with account of the principle of topologically face-centered anion packing: calculation method was presented and boundary conditions of CD concept applicability were considered. Tables of CD in oxides, sulfides and selenides, obtained in result of self-consistent calculations on the basis of experimental crystallographic data, are presented. Pair correlations between CD in oxides, sulfides and selenides were considered, their relationship with cation electron structure was established. Peculiarities of chemical bond in oxides, sulfides and selenides with face-centered anion packing were discussed

A kuroko-type polymetallic sulfide deposit in a submarine silicic caldera

Science.gov (United States)

Iizasa; Fiske; Ishizuka; Yuasa; Hashimoto; Ishibashi; Naka; Horii; Fujiwara; Imai; Koyama

1999-02-12

Manned submersible studies have delineated a large and actively growing Kuroko-type volcanogenic massive sulfide deposit 400 kilometers south of Tokyo in Myojin Knoll submarine caldera. The sulfide body is located on the caldera floor at a depth of 1210 to 1360 meters, has an area of 400 by 400 by 30 meters, and is notably rich in gold and silver. The discovery of a large Kuroko-type polymetallic sulfide deposit in this arc-front caldera raises the possibility that the numerous unexplored submarine silicic calderas elsewhere might have similar deposits.

Synthesis and X-ray diffraction studies of dysprosium-calcium ferrites Dy1-xCaxFeO3-y (0≤x≤2/3)

International Nuclear Information System (INIS)

Li, J.; Song, D.; Su, Z.; Wang, T.M.

1997-01-01

Samples of dysprosium-calcium ferrites Dy 1-x Ca x FeO 3-y with x ranging from 0 to 2/3 were novelly prepared in air by solid state reaction and characterized by X-ray powder diffraction. These samples are single-phased orthorhombic perovskite-type compounds belonging to the space group D 2h 16 -Pbnm. The lattice constants of the Dy 1-x Ca x FeO 3-y samples have been refined by Cohen's least-squares method. The initial substitution of Ca for Dy leads to a decrease of the lattice constants. Further substitution of Ca for Dy has hardly any influence on the lattice dimensions. (orig.)

'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

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.

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. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

International Nuclear Information System (INIS)

Taniguchi, Naoki; Kawasaki, Manabu

2008-01-01

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 2 S. 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

Understanding hydrodenitrogenation on novel unsupported sulfide Mo-W-Ni catalysis

Energy Technology Data Exchange (ETDEWEB)

Hein, J.; Hrabar, A.; Gutierrez, O.Y.; Lercher, J.A. [Technische Univ. Muenchen (Germany). Catalysis Research Center

2011-07-01

WNi, NiMo and Mo-W-Ni unsupported catalysts were synthesized, characterized and tested with respect to their hydrodenitrogenation properties using o-propylaniline as test reactant. The bimetallic oxide precursors are crystalline metallates, whereas the trimetallic materials are amorphous. In the sulfide form, the catalysts are mixtures of agglomerated Mo(W)S{sub 2} and Ni sulfides. The performance of all catalysts is similar, suggesting the same nature of active sites regardless the composition. Due to the lack of correlation between activity and density of coordinatively unsaturated sites of the catalysts, two kinds of active sites are proposed, i.e. coordinatively unsaturated sites and electron rich sites at the edges of the sulfides. (orig.)

Ionic liquid-modified metal sulfides/graphene oxide nanocomposites for photoelectric conversion

International Nuclear Information System (INIS)

Zhang, Yu; Zhang, Yù; Pei, Qi; Feng, Ting; Mao, Hui; Zhang, Wei; Wu, Shuyao; Liu, Daliang; Wang, Hongyu; Song, Xi-Ming

2015-01-01

Graphical abstract: - Highlights: • Metal sulfide (CdS, ZnS, Ag 2 S)/GO nanocomposites were prepared by electrostatic adherence. • Ionic liquid was used to link the metal sulfide and GO in the electrostatic adherence process. • The as-prepared samples showed enhanced photocurrent and highly efficient photocatalytic activity under visible light irradiation. - Abstract: Ionic liquid-modified metal sulfides/graphene oxide nanocomposites are prepared via a facile electrostatic adsorption. Ionic liquid (IL) is firstly used as surface modifier and structure-directing agent of metal sulfide (MS) crystallization process, obtaining ionic liquid modified-MS (IL-MS) nanoparticles with positive charges on surface. IL-MS/GO is obtained by electrostatic adherence between positively charged IL-MS and negatively charged graphene oxide (GO). The as-prepared sample shows enhanced photocurrent and highly efficient photocatalytic activity under visible light irradiation, indicating IL-MS/GO nanocomposites greatly promoted the separation of photogenerated electron–hole pairs

Single-molecule magnet behavior in an octanuclear dysprosium(iii) aggregate inherited from helical triangular Dy3 SMM-building blocks.

Science.gov (United States)

Zhang, Li; Zhang, Peng; Zhao, Lang; Wu, Jianfeng; Guo, Mei; Tang, Jinkui

2016-06-28

An unprecedented octanuclear dysprosium(iii) cluster with the formula [Dy8L6(μ3-OH)4(μ2-CH3O)2(CH3OH)6(H2O)2]·6H2O·10CH3OH·2CH3CN () based on a nonlinearly tritopic aroylhydrazone ligand H3L has been isolated, realizing the successful linking of pairwise interesting triangular Dy3 SMMs. It is noteworthy that two enantiomers (Λ and Δ configurations) individually behaving as a coordination-induced chirality presented in the Dy3 helicate are connected in the meso Dy8 cluster. Remarkably, alternating-current magnetic susceptibility measurements revealed that the Dy8 cluster shows typical SMM behavior inherited from its Dy3 helical precursor. It is one of the rare polynuclear Lnn SMMs (n > 7) under zero dc field.

Hydrotreatment of heavy oil from coal liquefaction on Sulfide Ni - W Catalysts

Energy Technology Data Exchange (ETDEWEB)

Zhi-ping Lei; Li-juan Gao; Heng-fu Shui; Shi-biao, Ren; Zhi-cai Wang; Kang-shi Gang, E-mail: shhf@ahut.edu.c [Anhui University of Technology, Maanshan (China). School of Chemistry and Chemical Engineering. Anhui Key Lab. of Coal Clean Conversion and Utilization

2011-07-01

Heavy oil (distillation temperature: 320-340 deg C) derived from the direct coal liquefaction process using Shengli coal were hydrotreated using sulfided Ni-Mo/Al{sub 2}O{sub 3}, Ni-W/Al{sub 2}O{sub 3}, and Ni-W/SiO{sub 2} catalysts respectively. The sulfided catalysts were characterized by BET, XRD, H{sub 2}-TPR and NH{sub 3}-TPD respectively. The evaluations of the hydrodenitrogenation (HDN) and hydrodearomatization (HDA) properties of heavy oil on the three catalysts were carried out at 400 deg C and 5.0 MPa initial H2 pressure. The W-based catalysts displayed better performances than Mo-based catalysts for the HDN and HDA reactions. Al{sub 2}O{sub 3} supported catalysts were found to have higher catalytic activities than on SiO{sub 2} supported ones. The activities of sulfided catalysts were associated mainly with the nature of active sites, acidity, metal sulfide crystallite size and the amount of the reducible sulfur species of metal sulfide. (author)

Effect of solvents on relation of intensities of bands of luminescence spectra of terbium and dysprosium ions in solutions of their complexes with acetoacetic ester

International Nuclear Information System (INIS)

Kononenko, L.I.; Bel'tyukova, S.V.; Meshkova, S.B.; Kravchenko, T.B.; Poluehktov, N.S.

1978-01-01

An investigation is made of the effect of different solvents on the ratio of the intensity of luminescence spectrum bands of terbium and dysprosium ions, corresponding and not corresponding to ''supersensitive'' transitions in complex compounds with acetoacetic ether. A dependence is established between these values and the dielectric constant of the solvent, and also parallels in their changes, which indicate the similar manifestation of the effect of solvents in both elements. A correlation is observed between ratios of the intensity of luminescence spectrum bands and values of forces of neodymium complex absorption band oscillators in different solvents

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

Evidence of molybdenum association with particulate organic matter under sulfidic conditions

DEFF Research Database (Denmark)

Dahl, Tais Wittchen; Chappaz, A.; Hoek, Joost

2017-01-01

, consisting of mainly Mo(IV)-sulfide compounds with molecular structures similar to Mo enzymes and to those found in natural euxinic sediments. Therefore, we propose that Mo removal in natural sulfidic waters can proceed via a non-Fe-assisted pathway that requires particulate organic matter (dead or living......The geochemical behavior of molybdenum (Mo) in the oceans is closely linked to the presence of sulfide species in anoxic environments, where Fe availability may play a key role in the Mo scavenging. Here, we show that Mo(VI) is reduced in the presence of particulate organic matter (represented...

A Study on Dielectric Properties of Cadmium Sulfide-Zinc Sulfide Core-Shell Nanocomposites for Application as Nanoelectronic Filter Component in the Microwave Domain

Science.gov (United States)

Devi, Jutika; Datta, Pranayee

2018-03-01

Complex permittivities of cadmium sulfide (CdS), zinc sulfide (ZnS), and of cadmium sulfide-zinc sulfide (CdS/ZnS) core-shell nanoparticles embedded in a polyvinyl alcohol matrix (PVA) were measured in liquid phase using a VectorNetwork Analyzer in the frequency range of 500 MHz-10 GHz. These nanocomposites are modeled as an embedded capacitor, and their electric field distribution and polarization have been studied using COMSOL Multiphysics software. By varying the thickness of the shell and the number of inclusions, the capacitance values were estimated. It was observed that CdS, ZnS and CdS/ZnS core-shell nanoparticles embedded in a polyvinyl alcohol matrix show capacitive behavior. There is a strong influence of the dielectric properties in the capacitive behavior of the embedded nanocapacitor. The capping matrix, position and filling factors of nanoinclusions all affect the capacitive behavior of the tested nanocomposites. Application of the CdS, ZnS and CdS/ZnS core-shell nanocomposite as the passive low-pass filter circuit has also been investigated. From the present study, it has been found that CdS/ZnS core-shell nanoparticles embedded in PVA matrix are potential structures for application as nanoelectronic filter components in different areas of communication.

A paradox resolved: Sulfide acquisition by roots of seep tubeworms sustains net chemoautotrophy

Science.gov (United States)

Freytag, John K.; Girguis, Peter R.; Bergquist, Derk C.; Andras, Jason P.; Childress, James J.; Fisher, Charles R.

2001-01-01

Vestimentiferan tubeworms, symbiotic with sulfur-oxidizing chemoautotrophic bacteria, dominate many cold-seep sites in the Gulf of Mexico. The most abundant vestimentiferan species at these sites, Lamellibrachia cf. luymesi, grows quite slowly to lengths exceeding 2 meters and lives in excess of 170–250 years. L. cf. luymesi can grow a posterior extension of its tube and tissue, termed a “root,” down into sulfidic sediments below its point of original attachment. This extension can be longer than the anterior portion of the animal. Here we show, using methods optimized for detection of hydrogen sulfide down to 0.1 μM in seawater, that hydrogen sulfide was never detected around the plumes of large cold-seep vestimentiferans and rarely detectable only around the bases of mature aggregations. Respiration experiments, which exposed the root portions of L. cf. luymesi to sulfide concentrations between 51–561 μM, demonstrate that L. cf. luymesi use their roots as a respiratory surface to acquire sulfide at an average rate of 4.1 μmol⋅g−1⋅h−1. Net dissolved inorganic carbon uptake across the plume of the tubeworms was shown to occur in response to exposure of the posterior (root) portion of the worms to sulfide, demonstrating that sulfide acquisition by roots of the seep vestimentiferan L. cf. luymesi can be sufficient to fuel net autotrophic total dissolved inorganic carbon uptake. PMID:11687647

Kinetic studies of sulfide mineral oxidation and xanthate adsorption

Science.gov (United States)

Mendiratta, Neeraj K.

2000-10-01

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 pyrrhotite, are few of the most abundant minerals, yet economically insignificant. Their existence with other sulfide minerals leads to an inefficient separation process as well as environmental problems, such as acid mine drainage during mining and processing and SO 2 emissions during smelting process. A part of the present study is focused on understanding their behavior, which leads to undesired flotation and difficulties in separation. The major reasons for the undesired flotation are attributed to the collectorless hydrophobicity and the activation with heavy metal ions. To better understand the collectorless hydrophobicity of pyrite, Electrochemical Impedance Spectroscopy (EIS) of freshly fractured pyrite electrodes was used to study the oxidation and reduction of the mineral. The EIS results showed that the rate of reaction increases with oxidation and reduction. At moderate oxidizing potentials, the rate of reaction is too slow to replenish hydrophilic iron species leaving hydrophobic sulfur species on the surface. However, at higher potentials, iron species are replaced fast enough to depress its flotation. Effects of pH and polishing were also explored using EIS. Besides collectorless hydrophobicity, the activation of pyrrhotite with nickel ions and interaction with xanthate ions makes the separation more difficult. DETA and SO2 are commonly used as pyrrhotite depressants; however, the mechanism is not very well understood. Contact angle measurements, cyclic voltammetry and Tafel

Remediation of arsenic-contaminated groundwater by in-situ stimulating biogenic precipitation of iron sulfides.

Science.gov (United States)

Pi, Kunfu; Wang, Yanxin; Xie, Xianjun; Ma, Teng; Liu, Yaqing; Su, Chunli; Zhu, Yapeng; Wang, Zhiqiang

2017-02-01

Severe health problems due to elevated arsenic (As) in groundwater have made it urgent to develop cost-effective technologies for As removal. This field experimental study tested the feasibility of in-situ As immobilization via As incorporation into newly formed biogenic Fe(II) sulfides in a typical As-affected strongly reducing aquifer at the central part of Datong Basin, China. After periodic supply of FeSO 4 into the aquifer for 25 d to stimulate microbial sulfate reduction, dissolved sulfide concentrations increased during the experiment, but the supplied Fe(II) reacted quickly with sulfide to form Fe(II)-sulfides existing majorly as mackinawite as well as a small amount of pyrite-like minerals in sediments, thereby restricting sulfide build-up in groundwater. After the completion of field experiment, groundwater As concentration decreased from an initial average value of 593 μg/L to 159 μg/L, with an overall As removal rate of 73%, and it further declined to 136 μg/L adding the removal rate up to 77% in 30 d after the experiment. The arsenite/As total ratio gradually increased over time, making arsenite to be the predominant species in groundwater residual As. The good correlations between dissolved Fe(II), sulfide and As concentrations, the increased abundance of As in newly-formed Fe sulfides as well as the reactive-transport modeling results all indicate that As could have been adsorbed onto and co-precipitated with Fe(II)-sulfide coatings once microbial sulfate reduction was stimulated after FeSO 4 supply. Under the strongly reducing conditions, sulfide may facilitate arsenate reduction into arsenite and promote As incorporation into pyrite or arsenopyrite. Therefore, the major mechanisms for the in-situ As-contaminated groundwater remediation can be As surface-adsorption on and co-precipitation with Fe(II) sulfides produced during the experimental period. Copyright © 2016. Published by Elsevier Ltd.

Controllable synthesis of hierarchical nickel cobalt sulfide with enhanced electrochemical activity

Science.gov (United States)

Tie, Jinjin; Han, Jiaxi; Diao, Guiqiang; Liu, Jiwen; Xie, Zhuopeng; Cheng, Gao; Sun, Ming; Yu, Lin

2018-03-01

The composition of nickel cobalt sulfide has great influence on its electrochemical performance. Herein, the nickel cobalt sulfide with different composition and mixed phase were synthesized by one-step solvothermal method through changing the molar ratio of Ni to Co in the reaction system. The electrochemical measurements showed that the nickel cobalt sulfide with a theoretical molar ratio of Ni/Co to be 1.5:1.5 (NCS-2) demonstrates the superior pseudocapacitive performance with a high specific capacitance (6.47 F cm-2 at 10 mA cm-2) and a favorable Coulombic efficiency (∼99%). Whereas, when applied as the catalyst for hydrogen evolution reaction in 1 M KOH aqueous electrolyte, the nickel cobalt sulfide with a theoretical molar ratio of Ni/Co is 1:2 (NCS-1) displays better catalytic activity, and it requires a relatively lower overpotential of 282 mV to deliver the current density of 10 mA cm-2.

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

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......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...

Solubility Measurements and Modeling of Zinc, Lead and Iron Sulfides at High Temperatures and High Pressures

DEFF Research Database (Denmark)

Carolina Figueroa Murcia, Diana; Fosbøl, Philip Loldrup; Thomsen, Kaj

Solubility measurements of sulfides in aqueous solutions are necessary to understand the behaviour of these scaling minerals in geothermal and oil reservoirs. The low solubility levels of Zinc Sulfide (ZnS), Lead Sulfide (PbS) and Iron Sulfide (FeS) make the solubility measurements a challenging...... oxygen atmosphere to avoid the risk of oxidation of sulfide minerals. The solution is kept in an equilibrium cell at constant temperature and pressure with continuous stirring. The concentration of Zn2+, Pb2+, Fe2+ and S2- are measured using Inductively Coupled Plasma Optical Emission spectrometry (ICP...

Electrochemical oxidation of iron and alkalinity generation for efficient sulfide control in sewers.

Science.gov (United States)

Lin, Hui-Wen; Kustermans, Caroline; Vaiopoulou, Eleni; Prévoteau, Antonin; Rabaey, Korneel; Yuan, Zhiguo; Pikaar, Ilje

2017-07-01

The addition of iron salts is one of the most commonly used dosing strategies for sulfide control in sewers. However, iron salts decrease the sewage pH which not only reduces the effectiveness of sulfide precipitation but also enhances the release of residual sulfide to the sewer atmosphere. Equally important, concentrated iron salt solutions are corrosive and their frequent transport, handling, and on-site storage often come with Occupational Health and Safety (OH&S) concerns. Here, we experimentally demonstrated a novel sulfide control approach using electrochemical systems with parallel placed iron electrodes. This enabled combining anodic dissolved iron species release with cathodic hydroxyl anion production, which alleviates all the aforementioned concerns. A long-term experiment was successfully carried out achieving an average sulfide removal efficiency of 95.4 ± 4.4% at low voltage input of 2.90 ± 0.54 V over the course of 8 weeks. This electrochemical method was demonstrated to successfully achieve efficient sulfide control. In addition, it increases the sewage pH, thereby overcoming the drawbacks associated with the pH decrease in the case of conventional iron salt dosing. Ferrous ions were produced at an overall coulombic efficiency (CE) of 98.2 ± 1.2%, whereas oxygen evolution and direct sulfide oxidation were not observed. Short-term experiments showed that increasing either inter-electrode gap or current density increased the cell voltage associated with the increase in the ohmic drop of the system. Overall, this study highlights the practical potential of in-situ generation of dissolved iron species and simultaneous hydroxyl anion generation for efficient sulfide control in sewers. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

International Nuclear Information System (INIS)

Kochetkova, N.V.; Bayandina, Yu.E.; Toptygina, G.M.; Shepot'ko, A.O.

1988-01-01

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 In 2 S 3 solubility is higher than that of sodium chloride

Corrosion Behavior of Cu40Zn in Sulfide-Polluted 3.5% NaCl Solution

Science.gov (United States)

Song, Q. N.; Xu, N.; Bao, Y. F.; Jiang, Y. F.; Gu, W.; Yang, Z.; Zheng, Y. G.; Qiao, Y. X.

2017-10-01

The corrosion behavior of a duplex-phase brass Cu40Zn in clean and sulfide-polluted 3.5% NaCl solutions was investigated by conducting electrochemical and gravimetric measurements. The corrosion product films were analyzed by scanning electron microscopy, energy-dispersive spectroscopy and x-ray diffraction. The presence of sulfide shifted the corrosion potential of Cu40Zn toward a more negative value by 100 mV and increased the mass loss rate by a factor of 1.257 compared with the result in the clean solution. The corrosion product film in the clean solution was thin and compact; it mainly consisted of oxides, such as ZnO and Cu2O. By contrast, the film in the sulfide-polluted solution was thick and porous. It mainly contained sulfides and zinc hydroxide chloride (i.e., Zn5(OH)8Cl2·H2O). The presence of sulfide ions accelerated the corrosion damage of Cu40Zn by hindering the formation of protective oxides and promoting the formation of a defective film which consisted of sulfides and hydroxide chlorides.

Sulfide stress corrosion study of a super martensitic stainless steel in H2S sour environments: Metallic sulfides formation and hydrogen embrittlement

Science.gov (United States)

Monnot, Martin; Nogueira, Ricardo P.; Roche, Virginie; Berthomé, Grégory; Chauveau, Eric; Estevez, Rafael; Mantel, Marc

2017-02-01

Thanks to their high corrosion resistance, super martensitic stainless steels are commonly used in the oil and gas industry, particularly in sour environments. Some grades are however susceptible to undergo hydrogen and mechanically-assisted corrosion processes in the presence of H2S, depending on the pH. The martensitic stainless steel EN 1.4418 grade exhibits a clear protective passive behavior with no sulfide stress corrosion cracking when exposed to sour environments of pH ≥ 4, but undergoes a steep decrease in its corrosion resistance at lower pH conditions. The present paper investigated this abrupt loss of corrosion resistance with electrochemical measurements as well as different physicochemical characterization techniques. Results indicated that below pH 4.0 the metal surface is covered by a thick (ca 40 μm) porous and defect-full sulfide-rich corrosion products layer shown to be straightforwardly related to the onset of hydrogen and sulfide mechanically-assisted corrosion phenomena.

Investigations on the role of hemoglobin in sulfide metabolism by intact human red blood cells.

Science.gov (United States)

Bianco, Christopher L; Savitsky, Anton; Feelisch, Martin; Cortese-Krott, Miriam M

2018-03-01

In addition to their role as oxygen transporters, red blood cells (RBCs) contribute to cardiovascular homeostasis by regulating nitric oxide (NO) metabolism via interaction of hemoglobin (Hb) with nitrite and NO itself. RBCs were proposed to also participate in sulfide metabolism. Although Hb is known to react with sulfide, sulfide metabolism by intact RBCs has not been characterized so far. Therefore we explored the role of Hb in sulfide metabolism in intact human RBCs. We find that upon exposure of washed RBCs to sulfide, no changes in oxy/deoxyhemoglobin (oxy/deoxyHb) are observed by UV-vis and EPR spectroscopy. However, sulfide reacts with methemoglobin (metHb), forming a methemoglobin-sulfide (metHb-SH) complex. Moreover, while metHb-SH is stable in cell-free systems even in the presence of biologically relevant thiols, it gradually decomposes to produce oxyHb, inorganic polysulfides and thiosulfate in intact cells, as detected by EPR and mass spectrometry. Taken together, our results demonstrate that under physiological conditions RBCs are able to metabolize sulfide via intermediate formation of a metHb-SH complex, which subsequently decomposes to oxyHb. We speculate that decomposition of metHb-SH is preceded by an inner-sphere electron transfer, forming reduced Hb (which binds oxygen to form oxyHb) and thiyl radical (a process we here define as "reductive sulfhydration"), which upon release, gives rise to the oxidized products, thiosulfate and polysulfides. Thus, not only is metHb an efficient scavenger and regulator of sulfide in blood, intracellular sulfide itself may play a role in keeping Hb in the reduced oxygen-binding form and, therefore, be involved in RBC physiology and function. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

Preparation of transition metal sulfide nanoparticles via hydrothermal route

International Nuclear Information System (INIS)

Fei-Ling, P.; Chin-Hua, C.; Sarani Zakaria; Tze-Khong, L.; Mohd Ambar Yarmo; Nay-Ming, H.

2010-01-01

Nano sized copper sulfide, iron sulfide and molybdenum sulfide were successfully synthesised via a simple hydrothermal method. Sodium thiosulfate pentahydrate (Na 2 S 2 O 3 ·5H 2 O) and hydroxylamine sulfate ((H 3 NO) 2 ·H 2 SO 4 ) were used as the starting materials and reacted with the transition metal source at 200 degree Celsius for 90 min. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and Fourier transform infrared spectroscopy (FTIR). Spherical shape CuS and FeS 2 nanoparticles with high crystallinity were successfully produced. The transmission electron micrographs revealed the well-dispersibility of the produced nanoparticles. Scanning electron micrograph showed the MoS 2 nanoparticles possessed a spherical shape with sheet-like structure covering on the outer surface of the particles. (author)

Combustion of gadolinium and dysprosium chelates as a cellular integrity marker in MR imaging

International Nuclear Information System (INIS)

Ericsson, A.; Bach-Gansmo, T.; Niklasson, F.; Hemmingsson, A.

1995-01-01

A combination of gadolinium (Gd) and dysprosium (Dy) chelates was investigated as a potential marker of cell-membrane integrity by means of a double-contrast effect in MR imaging. Blood samples with varying hematocrit (Hct) levels containing intact or lysed cells were used as model systems. With intact cells, the agents were assumed to be distributed solely extracellularly and the highest Hct studied (69%) was assumed to mimic the ratio of extracellular to intracellular water in tissue. The combined effect on image intensity of Gd (in a concentration corresponding to 0.2 mmol/kg b.w. in humans) and Dy (0.6 mmol/kg b.w.) applied simultaneously was a marked difference in signal intensity between samples with intact and lysed cells in both the T1- and T2-weighted spin-echo images with a corresponding increase in the contrast-to-noise ratio. This was the result of a T1 reduction caused by Gd with a negligible Dy susceptibility effect in areas with lysed cells. On the other hand, the Dy susceptibility effect (i.e. reduced apparent T2) dominated in areas with intact cells. Thus, the combination of Gd and Dy may serve as a marker of cell-membrane integrity in MR examinations. (orig.)

The lithiation and acyl transfer reactions of phosphine oxides, sulfides and boranes in the synthesis of cyclopropanes

DEFF Research Database (Denmark)

Clarke, Celia; Fox, David J; Pedersen, Daniel Sejer

2009-01-01

Phosphine oxides are lithiated much faster than phosphine sulfides and phosphine boranes. Phosphine sulfides are in turn lithiated much more readily than phosphine boranes. It was possible to trap a phosphine sulfide THF in one case which upon treatment with t-BuOK gave cyclopropane, showing...... that phosphine sulfides readily undergo both phosphinoyl transfer and cyclopropane ring closure just like their phosphine oxide counterparts. The obtained data show that phosphine oxides are easily lithiated and undergo phosphoryl transfer much more readily and faster than phosphine sulfides and phosphine...... boranes. The observations suggest that it would be possible to perform reactions involving phosphine oxides in the presence of phosphine boranes or phosphine sulfides, potentially allowing regioselective alkylation of phosphine oxides in the presence of phosphine boranes or phosphine sulfides....

Mechanism analysis of improved DLC films friction behaviors with liquid sulfidation treatment

International Nuclear Information System (INIS)

Zeng Qunfeng; Yu Fei; Dong Guangneng; Mao Junhong

2012-01-01

Highlights: ► Liquid sulfidation is applied to treat DLC films. ► Sulfur atoms are chemically bonded and the graphitization presented in the treated films. ► The treated films exhibited much lower coefficient of friction than the untreated films under dry friction condition. ► The sulfidation mechanisms are supposed as surface chemical reaction and surface diffusion. ► The presence of sulfur-containing materials and graphitization are beneficial to improve anti-friction behaviors of the treated films. - Abstract: Diamond like carbon (DLC) films were treated by liquid sulfidation to improve their friction behaviors. Friction behaviors of DLC films were experimentally evaluated in ambient air under dry friction using GCr15 steel ball sliding over DLC-coated steel flat in a ball-on-disk tribometer system. X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy were applied to identify the chemical composition and structure of DLC films. It was found that the content of sp 2 carbon bond increased and G peak shifted to high wave number after sulfidation treatment. The measurement results showed that sulfur atoms were chemically bonded and the graphitization occurred in the treated DLC films. It was indicated that the treated DLC films exhibited much better friction behaviors than the untreated films, especially for DLC films deposited with high nitrogen ratio. In this paper, we proposed the possible sulfidation mechanism of sulfurized DLC films. Sulfidation mechanism is postulated that thiourea reacted with oxygen to form sulfur-containing organic compounds which included CSSC, CSOH and (NH 2 )NH=CSO 2 H and surface diffusion during sulfidation treatment. The anti-friction behaviors of the treated DLC films can be attributed to the production of the compounds containing sulfur on the DLC film surface, the reduce of oxygen content and the presence of graphitization of DLC films.

Dysprosium doping induced shape and magnetic anisotropy of Fe{sub 3−x}Dy{sub x}O{sub 4} (x=0.01–0.1) nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Jain, Richa [School of Sciences, Indira Gandhi National Open University, Maidan Garhi, New Delhi 110068 (India); Department of Physics, ARSD college, University of Delhi, New Delhi 110021 (India); Luthra, Vandna [Department of Physics, Gargi College, Siri Fort Road, New Delhi 110049 (India); Gokhale, Shubha, E-mail: sgokhale@ignou.ac.in [School of Sciences, Indira Gandhi National Open University, Maidan Garhi, New Delhi 110068 (India)

2016-09-15

The effect of dysprosium doping on evolution of structural and magnetic properties of magnetite (Fe{sub 3}O{sub 4}) nanoparticles is reported. A standard route of co-precipitation was used for the synthesis of undoped and doped magnetite nanoparticles Fe{sub 3−x}Dy{sub x}O{sub 4} (x=0.0–0.1). Transmission electron microscopy (TEM) shows formation of round shaped particles with diameter in the range of 8–14 nm for undoped sample. On doping beyond x=0.01, the formation of rod like structures is initiated along with the round shaped particles. The number of rods is found to increase with increasing doping concentration. Magnetic characterization using Vibrating Sample Magnetometer (VSM) revealed doping dependent magnetic properties which can be correlated with the crystallite size as determined from X-ray diffraction (XRD). Enhancement in the saturation magnetization in the initial stages of doping can be explained on the basis of incorporation of Dy{sup 3+} ions in the inverse spinel structure at the octahedral site in place of Fe{sup 3+} ions. Subsequent decrease in saturation magnetization observed beyond x=0.03 could be attributed to precipitation of excess Dy in form of dysprosium ferrite phase. - Highlights: • Report on formation of nanorods in magnetite prompted by Dy doping. • Observation of anisotropic magnetic behaviour emanating from the shape anisotropy. • Evidence of Dy{sup 3+} ions occupying octahedral site in place of Fe{sup 3+} ions. • Nanorods envisaged to be useful as catalysts and in biomedical applications.

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.

Synthesis of zinc sulfide by chemical vapor deposition using an organometallic precursor: Di-tertiary-butyl-disulfide

International Nuclear Information System (INIS)

Vasekar, Parag; Dhakal, Tara; Ganta, Lakshmikanth; Vanhart, Daniel; Desu, Seshu

2012-01-01

Zinc sulfide has gained popularity in the last few years as a cadmium-free heterojunction partner for thin film solar cells and is seen as a good replacement for cadmium sulfide due to better blue photon response and non-toxicity. In this work, zinc sulfide films are prepared using an organic sulfur source. We report a simple and repeatable process for development of zinc sulfide using a cost-effective and less hazardous organic sulfur source. The development of zinc sulfide has been studied on zinc oxide-coated glass where the zinc oxide is converted into zinc sulfide. Zinc oxide grown by atomic layer deposition as well as commercially available zinc oxide-coated glass was used. The zinc sulfide synthesis has been studied and the films are characterized using scanning electron microscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and a UV–VIS spectrophotometer. XRD, XPS and optical characterization confirm the zinc sulfide phase formation. - Highlights: ► Synthesis of ZnS using a less-hazardous precursor, di-tertiary-butyl-disulfide. ► ZnS process optimized for two types of ZnO films. ► Preliminary results for a solar cell show an efficiency of 1.09%.

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

Effect of sulfide concentration on the location of the metal precipitates in inversed fluidized bed reactors

Energy Technology Data Exchange (ETDEWEB)

Villa-Gomez, D., E-mail: d.villagomez@unesco-ihe.org [Core Pollution Prevention and Control, UNESCO-IHE, Institute for Water Education, PO Box 3015, 2601 DA Delft (Netherlands); Ababneh, H.; Papirio, S.; Rousseau, D.P.L.; Lens, P.N.L. [Core Pollution Prevention and Control, UNESCO-IHE, Institute for Water Education, PO Box 3015, 2601 DA Delft (Netherlands)

2011-08-15

Highlights: {yields} Sulfide concentration governs the location of metal precipitates in sulfate reducing bioreactors. {yields} High dissolved sulfide induces metal precipitation in the bulk liquid as fines. {yields} Low dissolved sulfide concentrations yield local supersaturation and thus metal precipitation in the biofilm. -- Abstract: The effect of the sulfide concentration on the location of the metal precipitates within sulfate-reducing inversed fluidized bed (IFB) reactors was evaluated. Two mesophilic IFB reactors were operated for over 100 days at the same operational conditions, but with different chemical oxygen demand (COD) to SO{sub 4}{sup 2-} ratio (5 and 1, respectively). After a start up phase, 10 mg/L of Cu, Pb, Cd and Zn each were added to the influent. The sulfide concentration in one IFB reactor reached 648 mg/L, while it reached only 59 mg/L in the other one. In the high sulfide IFB reactor, the precipitated metals were mainly located in the bulk liquid (as fines), whereas in the low sulfide IFB reactor the metal preciptiates were mainly present in the biofilm. The latter can be explained by local supersaturation due to sulfide production in the biofilm. This paper demonstrates that the sulfide concentration needs to be controlled in sulfate reducing IFB reactors to steer the location of the metal precipitates for recovery.

Sythesis of metal sulfide nanomaerials via thermal decomposition of single-source percursors

Energy Technology Data Exchange (ETDEWEB)

Jen-La Plante, Ilan; Zeid, Tahani W.; Yang, Peidong; Mokari, Taleb

2010-06-03

In this report, we present a synthetic method for the formation of cuprous sulfide (Cu2S) and lead sulfide (PbS) nanomaterials directly on substrates from the thermolysis of single-source precursors. We find that the final morphology and arrangement of the nanomaterials may be controlled through the concentration of the dissolved precursors and choice of solvent. One-dimensional (1-D) morphologies may also be grown onto substrates with the addition of a metal catalyst layer through solution-liquid-solid (SLS) growth. These synthetic techniques may be expanded to other metal sulfide materials.

A physiologically based kinetic model for bacterial sulfide oxidation.

Science.gov (United States)

Klok, Johannes B M; de Graaff, Marco; van den Bosch, Pim L F; Boelee, Nadine C; Keesman, Karel J; Janssen, Albert J H

2013-02-01

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 concluded that the oxidation-reduction state of cytochrome c is a direct measure for the bacterial end-product formation. Given this physiological feature, incorporation of the oxidation state of cytochrome c in a mathematical model for the bacterial oxidation kinetics will yield a physiologically based model structure. This paper presents a physiologically based model, describing the dynamic formation of the various end-products in the biodesulfurization process. It consists of three elements: 1) Michaelis-Menten kinetics combined with 2) a cytochrome c driven mechanism describing 3) the rate determining enzymes of the respiratory system of haloalkaliphilic sulfide oxidizing bacteria. The proposed model is successfully validated against independent data obtained from biological respiration tests and bench scale gas-lift reactor experiments. The results demonstrate that the model is a powerful tool to describe product formation for haloalkaliphilic biomass under dynamic conditions. The model predicts a maximum S⁰ formation of about 98 mol%. A future challenge is the optimization of this bioprocess by improving the dissolved oxygen control strategy and reactor design. Copyright © 2012 Elsevier Ltd. All rights reserved.

ELECTROCHEMICAL DETERMINATION OF HYDROGEN SULFIDE AT CARBON NANOTUBE MODIFIED ELECTRODES. (R830900)

Science.gov (United States)

Carbon nanotube (CNT) modified glassy carbon electrodes exhibiting a strong and stable electrocatalytic response towards sulfide are described. A substantial (400 mV) decrease in the overvoltage of the sulfide oxidation reaction (compared to ordinary carbon electrodes) is...

A real support effect on the hydrodeoxygenation of methyl oleate by sulfided NiMo catalysts

NARCIS (Netherlands)

Coumans, A.E.; Hensen, E.J.M.

2017-01-01

The effect of the support on the catalytic performance of sulfided NiMo in the hydrodeoxygenation of methyl oleate as a model compound for triglyceride upgrading to green diesel was investigated. NiMo sulfides were prepared by impregnation and sulfidation on activated carbon, silica, γ-alumina and

Sulfide Mineral Surfaces

International Nuclear Information System (INIS)

Rosso, Kevin M.; Vaughan, David J.

2006-01-01

The past twenty years or so have seen dramatic development of the experimental and theoretical tools available to study the surfaces of solids at the molecular (?atomic resolution?) scale. On the experimental side, two areas of development well illustrate these advances. The first concerns the high intensity photon sources associated with synchrotron radiation; these have both greatly improved the surface sensitivity and spatial resolution of already established surface spectroscopic and diffraction methods, and enabled the development of new methods for studying surfaces. The second centers on the scanning probe microscopy (SPM) techniques initially developed in the 1980's with the first scanning tunneling microscope (STM) and atomic force microscope (AFM) experiments. The direct 'observation' of individual atoms at surfaces made possible with these methods has truly revolutionized surface science. On the theoretical side, the availability of high performance computers coupled with advances in computational modeling has provided powerful new tools to complement the advances in experiment. Particularly important have been the quantum mechanics based computational approaches such as density functional theory (DFT), which can now be easily used to calculate the equilibrium crystal structures of solids and surfaces from first principles, and to provide insights into their electronic structure. In this chapter, we review current knowledge of sulfide mineral surfaces, beginning with an overview of the principles relevant to the study of the surfaces of all crystalline solids. This includes the thermodynamics of surfaces, the atomic structure of surfaces (surface crystallography and structural stability, adjustments of atoms at the surface through relaxation or reconstruction, surface defects) and the electronic structure of surfaces. We then discuss examples where specific crystal surfaces have been studied, with the main sulfide minerals organized by structure type

Sulfide Mineral Surfaces

Energy Technology Data Exchange (ETDEWEB)

Rosso, Kevin M.; Vaughan, David J.

2006-08-01

The past twenty years or so have seen dramatic development of the experimental and theoretical tools available to study the surfaces of solids at the molecular (?atomic resolution?) scale. On the experimental side, two areas of development well illustrate these advances. The first concerns the high intensity photon sources associated with synchrotron radiation; these have both greatly improved the surface sensitivity and spatial resolution of already established surface spectroscopic and diffraction methods, and enabled the development of new methods for studying surfaces. The second centers on the scanning probe microscopy (SPM) techniques initially developed in the 1980's with the first scanning tunneling microscope (STM) and atomic force microscope (AFM) experiments. The direct 'observation' of individual atoms at surfaces made possible with these methods has truly revolutionized surface science. On the theoretical side, the availability of high performance computers coupled with advances in computational modeling has provided powerful new tools to complement the advances in experiment. Particularly important have been the quantum mechanics based computational approaches such as density functional theory (DFT), which can now be easily used to calculate the equilibrium crystal structures of solids and surfaces from first principles, and to provide insights into their electronic structure. In this chapter, we review current knowledge of sulfide mineral surfaces, beginning with an overview of the principles relevant to the study of the surfaces of all crystalline solids. This includes the thermodynamics of surfaces, the atomic structure of surfaces (surface crystallography and structural stability, adjustments of atoms at the surface through relaxation or reconstruction, surface defects) and the electronic structure of surfaces. We then discuss examples where specific crystal surfaces have been studied, with the main sulfide minerals organized by

New technology for sulfide reductions and increased oil recovery: Petroleum project fact sheet

Energy Technology Data Exchange (ETDEWEB)

NONE

1999-12-14

This Fact Sheet is written for the Inventions and Innovations Program about a new technology for sulfide reduction and increased oil recovery. The new technology, called Bio-Competitive Exclusion (BCX), results in greater oil production and prevents the production of corrosive hydrogen sulfide in oil and gas reservoirs. This BCX process is initiated and maintained by a new product, called Max-Well 2000, in which nutrients are custom designed to stimulate targeted beneficial microorganisms that live in every oil and gas reservoir. Rapid growth of these microorganisms excludes activity of harmful sulfide-producing bacteria and produces by-products that serve as effective tertiary oil recovery agents and as sulfide degradation agents. Oil and gas production is both increased and sweetened.

Response of gut health and microbiota to sulfide exposure in Pacific white shrimp Litopenaeus vannamei.

Science.gov (United States)

Suo, Yantong; Li, Erchao; Li, Tongyu; Jia, Yongyi; Qin, Jian G; Gu, Zhimin; Chen, Liqiao

2017-04-01

Sulfide is a natural and widely distributed toxicant. It can be commonly found on the interface between water and sediment in the aquatic environment. The Pacific white shrimp Litopenaeus vannamei starts life in the benthic zone soon after the mysis stage, an early stage of post larvae. Therefore, L. vannamei is inevitably affected by exposure to sulfide released from pond sediment. This study explored the toxicant effect of different concentrations of sulfide on the intestinal health and microbiota of Pacific white shrimp by monitoring the change of expression of inflammatory, immune related cytokines, and the structure of the intestinal microbiota. The gut histology, expressions of inflammatory and immune related cytokines (tumor necrosis factor-alpha, C-type lectin 3, myostatin and heat shock transcription factor 1), and the microbiota were determined in L. vannamei after exposure to 0 (control), 425.5 (1/10 LC 50-96 h), and 851 μg/L (1/5 LC 50-96 h) of sulfide for 21 days. With the increase of sulfide concentration, intestinal injury was aggravated and the inflammatory and immune related cytokines generated a range of reactions. The expression of myostatin (MSTN) was significantly down-regulated by the concentration of sulfide exposure. No difference in the expression of heat shock transcription factor 1 (HSF1) was found between the control and shrimp exposed to 425.5 μg/L, but significantly higher HSF1 expression was found in shrimp exposed to 851 μg/L of sulfide. Significantly higher values of tumor necrosis factor-alpha (TNF-α) and C-type lectin 3 (CTL3) were found in the shrimp exposed to 425.5 μg/L of sulfide compared to the control, but a lower value was found in the shrimp exposed to 851 μg/L (P < 0.05). Sulfide also changed the intestinal microbial communities. The abundance of pathogenic bacteria, such as Cyanobacteria, Vibrio and Photobacterium, increased significantly with exposure to the increasing concentration of sulfide. The

Sulfide Generation by Dominant Halanaerobium Microorganisms in Hydraulically Fractured Shales

Energy Technology Data Exchange (ETDEWEB)

Booker, Anne E.; Borton, Mikayla A.; Daly, Rebecca A.; Welch, Susan A.; Nicora, Carrie D.; Hoyt, David W.; Wilson, Travis; Purvine, Samuel O.; Wolfe, Richard A.; Sharma, Shikha; Mouser, Paula J.; Cole, David R.; Lipton, Mary S.; Wrighton, Kelly C.; Wilkins, Michael J.; McMahon, Katherine

2017-07-05

Hydraulic fracturing of black shale formations has greatly increased United States oil and natural gas recovery. However, the accumulation of biomass in subsurface reservoirs and pipelines is detrimental because of possible well souring, microbially induced corrosion, and pore clogging. Temporal sampling of produced fluids from a well in the Utica Shale revealed the dominance ofHalanaerobiumstrains within thein situmicrobial community and the potential for these microorganisms to catalyze thiosulfate-dependent sulfidogenesis. From these field data, we investigated biogenic sulfide production catalyzed by aHalanaerobiumstrain isolated from the produced fluids using proteogenomics and laboratory growth experiments. Analysis ofHalanaerobiumisolate genomes and reconstructed genomes from metagenomic data sets revealed the conserved presence of rhodanese-like proteins and anaerobic sulfite reductase complexes capable of converting thiosulfate to sulfide. Shotgun proteomics measurements using aHalanaerobiumisolate verified that these proteins were more abundant when thiosulfate was present in the growth medium, and culture-based assays identified thiosulfate-dependent sulfide production by the same isolate. Increased production of sulfide and organic acids during the stationary growth phase suggests that fermentativeHalanaerobiumuses thiosulfate to remove excess reductant. These findings emphasize the potential detrimental effects that could arise from thiosulfate-reducing microorganisms in hydraulically fractured shales, which are undetected by current industry-wide corrosion diagnostics.

IMPORTANCEAlthough thousands of wells in deep shale formations across the United States have been hydraulically fractured for oil and gas recovery, the impact of microbial metabolism within these environments is poorly understood. Our

Effect of pre-oxidation on high temperature sulfidation behavior of FeCr and FeCrAl alloys

Directory of Open Access Journals (Sweden)

Pillis Marina Fuser

2004-01-01

Full Text Available High temperature corrosion of structural alloys in sulfur bearing environments is many orders of magnitude higher than in oxidizing environments. Efforts to increase sulfidation resistance of these alloys include addition of alloying elements. Aluminum additions to iron-chromium alloys bring about increase in sulfidation resistance. This paper reports the effect of pre-oxidation on the sulfidation behavior of Fe-20Cr and Fe-20Cr-5Al alloys in H2-2% H2S environment at 800 °C. The surfaces of sulfidized specimens were also examined. Pre-oxidation of the two alloys results in an incubation period during subsequent sulfidation. After this incubation period, the Fe-20Cr alloy showed sulfidation behavior similar to that when the alloy was not pre-oxidized. The incubation period during sulfidation of the Fe-20Cr-5Al alloy was significantly longer, over 45 h, compared to 2 h for the Al free alloy. Based on the microscopic and gravimetric data a mechanism for sulfidation of these alloys with pre-oxidation has been proposed.

Reduction kinetics of zinc and cadmium sulfides with hydrogen

International Nuclear Information System (INIS)

Turgenev, I.S.; Kabisov, I.Kh.; Zviadadze, G.N.; Vasil'eva, O.Yu.

1985-01-01

Kinetics of reduction processes of zinc sulfide in the temperature range 800-1100 deg C and of cadmium sulfide 600-900 deg C has been stodied. Activation energies and reaction order in terms of hydrogen are calculated. Thermodynamic processes of reduction depend on aggregate state of the metal formed. For vaporous zinc in the temperature range 1050-950 deq C activation energy constitutes 174 kJ/mol, for liquid in the range 900-850 deg - 151 kJ/mol and reaction order in terms of hydrogen is 1.0. For vaporous cadmium in the temperature range 900-700 deg C activation energy constitutes 144 kJ/mol and reaction order in terms of hydrogen is 0.86, for liquid in the range 675-600 deg C 127 kJ/mol and 0.8 respectively. The processes of zinc and cadmium sulfide reduction proceed in kinetic regime and are limited by the rate of chemical reaction

Carbon steel protection in G.S. (Girlder sulfide) plants. CITROSOLV process influence. Pt. 6

International Nuclear Information System (INIS)

Lires, O.A.; Burkart, A.L.; Delfino, C.A.; Rojo, E.A.

1988-01-01

In order to protect carbon steel towers and piping of Girlder sulfide (G.S.) experimental heavy water plants against corrosion produced by the action of aqueous solutions of hydrogen sulfides, a method, previously published, was developed. Carbon steel, exposed to saturated aqueous solutions of hydrogen sulfide, forms iron sulfide scales. In oxygen free solutions evolution of corrosion follows the sequence: mackinawite → cubic ferrous sulfide → troilite → pyrrotite → pyrite. Scales formed by pyrrotite-pyrite or pyrite are the most protective layers (these are obtained at 130 deg C, 2 MPa, for periods of 14 days). CITROSOLV Process (Pfizer) is used to descaling and passivating stainless steel plant's components. This process must be used in mixed (carbon steel - stainless steel) circuits and may cause the formation of magnetite scales over the carbon steel. The influence of magnetite in the pyrrotite-pyrite scales formation is studied in this work. (Author) [es

Structural and Mechanistic Insights into Hemoglobin-catalyzed Hydrogen Sulfide Oxidation and the Fate of Polysulfide Products

Energy Technology Data Exchange (ETDEWEB)

Vitvitsky, Victor; Yadav, Pramod K.; An, Sojin; Seravalli, Javier; Cho, Uhn-Soo; Banerjee, Ruma (Michigan-Med); (UNL)

2017-02-17

Hydrogen sulfide is a cardioprotective signaling molecule but is toxic at elevated concentrations. Red blood cells can synthesize H2S but, lacking organelles, cannot dispose of H2S via the mitochondrial sulfide oxidation pathway. We have recently shown that at high sulfide concentrations, ferric hemoglobin oxidizes H2S to a mixture of thiosulfate and iron-bound polysulfides in which the latter species predominates. Here, we report the crystal structure of human hemoglobin containing low spin ferric sulfide, the first intermediate in heme-catalyzed sulfide oxidation. The structure provides molecular insights into why sulfide is susceptible to oxidation in human hemoglobin but is stabilized against it in HbI, a specialized sulfide-carrying hemoglobin from a mollusk adapted to life in a sulfide-rich environment. We have also captured a second sulfide bound at a postulated ligand entry/exit site in the α-subunit of hemoglobin, which, to the best of our knowledge, represents the first direct evidence for this site being used to access the heme iron. Hydrodisulfide, a postulated intermediate at the junction between thiosulfate and polysulfide formation, coordinates ferric hemoglobin and, in the presence of air, generated thiosulfate. At low sulfide/heme iron ratios, the product distribution between thiosulfate and iron-bound polysulfides was approximately equal. The iron-bound polysulfides were unstable at physiological glutathione concentrations and were reduced with concomitant formation of glutathione persulfide, glutathione disulfide, and H2S. Hence, although polysulfides are unlikely to be stable in the reducing intracellular milieu, glutathione persulfide could serve as a persulfide donor for protein persulfidation, a posttranslational modification by which H2S is postulated to signal.

Er2S[SiO4]: An erbium sulfide ortho-oxosilicate with unusual sulfide anion coordination

International Nuclear Information System (INIS)

Hartenbach, Ingo; Lauxmann, Petra; Schleid, Thomas

2004-01-01

During the reaction of cadmium sulfide with erbium and sulfur in evacuated silica ampoules pink lath-shaped crystals of Er 2 S[SiO 4 ] occur as by-product which were characterized by X-ray single crystal structure analysis. The title compound crystallizes orthorhombically in the space group Cmce (a = 1070.02(8), b = 1235.48(9), c = 683.64(6) pm) with eight formula units per unit cell. Besides isolated ortho-oxosilicate units [SiO 4 ] 4- , the crystal structure contains two crystallographically independent Er 3+ cations which are both eightfold coordinated by six oxygen and two sulfur atoms. The sulfide anions are surrounded by four erbium cations each in the shape of very distorted tetrahedra. These excentric [SEr 4 ] 10+ tetrahedra build up layers according to 2 ∞ [SEr 4/2 ] 4+ by vertex- and edge-connection. They are piled parallel to (010) and separated by the isolated ortho-oxosilicate tetrahedra. (Abstract Copyright [2004], Wiley Periodicals, Inc.) [de

Supramolecular binding and release of sulfide and hydrosulfide anions in water.

Science.gov (United States)

Vázquez, J; Sindelar, V

2018-06-05

Hydrogen sulfide (H2S) has become an important target for research due to its physiological properties as well as its potential applications in medicine. In this work, supramolecular binding of sulfide (S2-) and hydrosulfide (HS-) anions in water is presented for the first time. Bambusurils were used to slow down the release of these anions in water.

Study of radiation synovectomy using 188Re-sulfide in hemophilic arthritis

International Nuclear Information System (INIS)

Li, P.Y.; Cheng, G.; Jiang, X.F.; Wang, X.F.; Shen, Z.M.; Zhang, Z.H.

2002-01-01

Purpose: Based on results of previous animal studies, the efficacy of 188 Re-sulfide on radiation synovectomy in hemophilia synovitis.was evaluated. Material and Methods: 188 Re-sulfide suspension was produced by dispersion method. 25 hemophilic patients with 30 synovitic joints including 22 knees and 8 ankles received the radiation synovectomy. The stage of synovitic joint was classified by joint score including the pain, stability and range of motion and MR score. The doses of 188 Re-sulfide injected into knee and ankle were determined as 12mCi and 6mCi respectively, according to the depth and curve and the results of our previous animal study. To exam the distribution of 188 Re-sulfide in vivo after the injection, a whole-body scan was taken 24 and 48 hours later to calculate the retention of 188 Re-sulfide in joint by percentage of join counts in whole body. The follow up was take place at 6-12 months after the synovectomy by joint score, MRI score, synovial structure, the times and interval of hemorrhage of the joints. Results: Few patients complained discomfort after the injection such as hurt of the superficial tissues around the injected point and swelling (2 patients,.8%).The symptoms in this two patients continued up to 3 days and gradually decreased in severity. All patients felt relief of the pain and swelling in joints. 90% joints including 20 knees and 7 ankles did not bleed any more during the 3-month term of follow up, 3 joints from 2 patients with intra-article bleeding had hemorrhage in one month after long distance walk. 16%(5/30) of joints including 4 knees and 1 ankles had recurrent hemorrhage in 12 months after the radiation synovectomy. However, their interval of intra-article bleeding was prolonged MRI showed the thick synovium became thin, villi reduced and the joint edema relieved. The retention of 188 Re-sulfide in administrated joint was more than 95% until 48 hours later. No any sign of radioactive distribution was found in bone marrow

Hydrogen sulfide metabolism regulates endothelial solute barrier function

Directory of Open Access Journals (Sweden)

Shuai Yuan

2016-10-01

Full Text Available Hydrogen sulfide (H2S is an important gaseous signaling molecule in the cardiovascular system. In addition to free H2S, H2S can be oxidized to polysulfide which can be biologically active. Since the impact of H2S on endothelial solute barrier function is not known, we sought to determine whether H2S and its various metabolites affect endothelial permeability. In vitro permeability was evaluated using albumin flux and transendothelial electrical resistance. Different H2S donors were used to examine the effects of exogenous H2S. To evaluate the role of endogenous H2S, mouse aortic endothelial cells (MAECs were isolated from wild type mice and mice lacking cystathionine γ-lyase (CSE, a predominant source of H2S in endothelial cells. In vivo permeability was evaluated using the Miles assay. We observed that polysulfide donors induced rapid albumin flux across endothelium. Comparatively, free sulfide donors increased permeability only with higher concentrations and at later time points. Increased solute permeability was associated with disruption of endothelial junction proteins claudin 5 and VE-cadherin, along with enhanced actin stress fiber formation. Importantly, sulfide donors that increase permeability elicited a preferential increase in polysulfide levels within endothelium. Similarly, CSE deficient MAECs showed enhanced solute barrier function along with reduced endogenous bound sulfane sulfur. CSE siRNA knockdown also enhanced endothelial junction structures with increased claudin 5 protein expression. In vivo, CSE genetic deficiency significantly blunted VEGF induced hyperpermeability revealing an important role of the enzyme for barrier function. In summary, endothelial solute permeability is critically regulated via exogenous and endogenous sulfide bioavailability with a prominent role of polysulfides.

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

Science.gov (United States)

Picard, Aude A.; Gartman, Amy; Girguis, Peter R.

2016-01-01

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.

Remediation of arsenic and lead with nanocrystalline zinc sulfide.

Science.gov (United States)

Piquette, Alan; Cannon, Cody; Apblett, Allen W

2012-07-27

Nanocrystalline (1.7 ± 0.3 nm) zinc sulfide with a specific surface area up to 360 m(2) g(-1) was prepared from the thermal decomposition of a single-source precursor, zinc ethylxanthate. Zinc ethylxanthate decomposes to cubic zinc sulfide upon exposure to temperatures greater than or equal to 125 °C. The resulting zinc sulfide was tested as a water impurity extractant. The target impurities used in this study were As(5+), As(3+), and Pb(2+). The reaction of the nanocrystalline ZnS with Pb(2+) proceeds as a replacement reaction where solid PbS is formed and Zn(2+) is released into the aqueous system. Removal of lead to a level of less than two parts per billion is achievable. The results of a detailed kinetics experiment between the ZnS and Pb(2+) are included in this study. Unlike the instance of lead, both As(5+) and As(3+) adsorb on the surface of the ZnS extractant as opposed to an ion-exchange process. An uptake capacity of > 25 mg g(-1) for the removal of As(5+) is possible. The uptake of As(3+) appears to proceed by a slower process than that of the As(5+) with a capacity of nearly 20 mg g(-1). The nanocrystalline zinc sulfide was extremely successful for the removal of arsenic and lead from simulated oil sand tailing pond water.

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

International Nuclear Information System (INIS)

Delfino, C.A.

1986-01-01

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) [es

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

International Nuclear Information System (INIS)

Mazilu, Mihai; Costescu, Sanda

2002-01-01

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

Effect of ambient hydrogen sulfide on the physical properties of vacuum evaporated thin films of zinc sulfide

Energy Technology Data Exchange (ETDEWEB)

Singh, Beer Pal [Department of Physics, C.C.S. University, Meerut 250004 (India)], E-mail: drbeerpal@gmail.com; Singh, Virendra [Forensic Science Laboratory, Malviya Nagar, New Delhi 110017 (India); Tyagi, R.C.; Sharma, T.P. [Department of Physics, C.C.S. University, Meerut 250004 (India)

2008-02-15

Evaporated thin films of zinc sulfide (ZnS) have been deposited in a low ambient atmosphere of hydrogen sulfide (H{sub 2}S {approx}10{sup -4} Torr). The H{sub 2}S atmosphere was obtained by a controlled thermal decomposition of thiourea [CS(NH{sub 2}){sub 2}] inside the vacuum chamber. It has been observed that at elevated substrates temperature of about 200 deg. C helps eject any sulfur atoms deposited due to thermal decomposition of ZnS during evaporation. The zinc ions promptly recombine with H{sub 2}S to give better stoichiometry of the deposited films. Optical spectroscopy, X-ray diffraction patterns and scanning electron micrographs depict the better crystallites and uniformity of films deposited by this technique. These deposited films were found to be more adherent to the substrates and are pinhole free, which is a very vital factor in device fabrication.

Acid volatile sulfide (AVS)- a comment

NARCIS (Netherlands)

Meysman, F.J.R.; Middelburg, J.J.

2005-01-01

The review by Rickard and Morse (this volume) adequately summarizes our current understanding with respect to acid-volatile sulfides (AVS). At the same time, this review addresses some of the misunderstandings with regard to measurements and dynamics of this important sedimentary sulfur pool. In

Carbon a support for sulfide catalysts

NARCIS (Netherlands)

Vissers, J.P.R.; Lensing, T.J.; Mercx, F.P.M.; Beer, de V.H.J.; Prins, R.

1983-01-01

Two types of carbon materials, carbon black composite and carbon covered alumina, were studied for-their use as support for sulfide catalysts. The following parameters were varied: type of carbon black, carbon coverage of the alumina and carbon pretreatment. Pore size distributions were determined

Hydrogen sulfide in plants: from dissipation of excess sulfur to signaling molecule.

Science.gov (United States)

Calderwood, Alexander; Kopriva, Stanislav

2014-09-15

Sulfur is essential in all organisms for the synthesis of amino acids cysteine and methionine and as an active component of numerous co-factors and prosthetic groups. However, only plants, algae, fungi, and some prokaryotes are capable of using the abundant inorganic source of sulfur, sulfate. Plants take sulfate up, reduce it, and assimilate into organic compounds with cysteine being the first product of the pathway and a donor of reduced sulfur for synthesis of other S-containing compounds. Cysteine is formed in a reaction between sulfide, derived from reduction of sulfite and an activated amino acid acceptor, O-acetylserine. Sulfide is thus an important intermediate in sulfur metabolism, but numerous other functions in plants has been revealed. Hydrogen sulfide can serve as an alternative source of sulfur for plants, which may be significant in anaerobic conditions of waterlogged soils. On the other hand, emissions of hydrogen sulfide have been detected from many plant species. Since the amount of H2S discharged correlated with sulfate supply to the plants, the emissions were considered a mechanism for dissipation of excess sulfur. Significant hydrogen sulfide emissions were also observed in plants infected with pathogens, particularly with fungi. H2S thus seems to be part of the widely discussed sulfur-induced-resistance/sulfur-enhanced-defense. Recently, however, more evidence has emerged for a role for H2S in regulation and signaling. Sulfide stabilizes the cysteine synthase complex, increasing so the synthesis of its acceptor O-acetylserine. H2S has been implicating in regulation of plant stress response, particularly draught stress. There are more and more examples of processes regulated by H2S in plants being discovered, and hydrogen sulfide is emerging as an important signaling molecule, similar to its role in the animal and human world. How similar the functions, and homeostasis of H2S are in these diverse organisms, however, remains to be elucidated

Textured dysprosium and gadolinium poles for high-field, short-period hybrid undulators

International Nuclear Information System (INIS)

Murokh, Alex; Solovyov, Vyacheslav; Agustsson, Ron; O'Shea, Finn H.; Chubar, Oleg; Chen, Yung; Grandsaert, Thomas

2014-01-01

We discuss the feasibility of enhancement of the gap field in a short-period hybrid undulator by using pole inserts with the saturation inductance B s , over that of iron, 2 T. Dysprosium metal, with the saturation inductance of 3.4 T below 90 K, and Gadolinium with B s =2.7 T, appear as good candidates as the optimized pole material. However, due to the high magnetic anisotropy of Dy, such a high level of magnetization can only be realized when the external field lies in the basal plane. This implies that the pole has to be single-crystalline or highly textured. Considering that growing large, >10mm, Dy single crystals is difficult, we propose secondary recrystallization as a method to induce the required texture in thin Dy and Gd foils. The textured foils can be stacked to produce pole inserts of the desired geometry and orientation. Results of small-scale processing and magnetic measurements of thin (20–60 μ) foils provide evidence that the required texture quality can be achieved by a relatively simple sequence of heat-treatments and cold rolling. The advantage of textured Dy and Gd poles is demonstrated in a several period test undulator. -- Highlights: • Textured rare-earth materials for use as undulator pole materials. • We measure the development of texture in Dy and Gd. • We compare the rare-earth materials with high saturation steel in undulators. • Thin sheets of Dy and Gd materials perform similar to single crystals

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

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 by the solid reactive iron content. Two processes of diffusion-limited pyrite formation were identified. The first process includes pyrite precipitation with the accumulation of iron sulfide precursors with the average chemical composition of FeSn (n = 1.10-1.29), including greigite. Elemental sulfur...... 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...

An XPS [x-ray photoelectron spectroscopy] study of the sulfidation-regeneration cycle of a hydroprocessing catalyst

Energy Technology Data Exchange (ETDEWEB)

Shang, D.Y.; Adnot, A.; Kaliaguine, S. (Laval Univ., Ste-Foy, PQ (Canada)); Chmielowiec, J. (Petro Canada Products Co., Mississauga, ON (Canada))

1993-10-01

The formation of sulfates in an industrial Ni-W hydroprocessing (HP) catalyst was investigated by x-ray photoelectron spectroscopy (XPS). A small fluidized bed test unit with on-line sampling device was constructed to simulate industrial sulfidation and oxyregeneration processes of HP catalysts. The results obtained show that the sulfates observed on the surface of sulfided catalysts are not formed during the sulfidation process. Two oxidation processes seem to be responsible for the formation of sulfates: one happens when the catalyst is exposed to air before it is properly cooled and the other is a slow conversion at ambient temperature. The two different processes might be associated to different sulfidic species formed during the sulfidation processes, with the sulfides in the bulk of catalyst particles being more easily oxidized than the ones on the external surface of the catalyst particles. The sulfate formed during the air oxidation of sulfided catalysts, as well as that after oxyregeneration, is not aluminum sulfate but nickel sulfate in both cases. XPS results also indicate that oxygenates in the feedstock are not directly involved in the sulfate formation. 18 refs., 9 figs., 6 tabs.

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.

Synthesis and characterization of titanium oxide/bismuth sulfide nanorods for solar cells applications

International Nuclear Information System (INIS)

Solis, M.; Rincon, M. E.

2008-01-01

In the present work is showed the synthesis and characterization of titanium oxide/bismuth sulfide nanowires hetero-junctions for solar cells applications. Conductive glass substrates (Corning 25 x 75 mm) were coated with a thin layer of sol-gel TiO2 and used as substrates for the subsequent deposition of bismuth sulfide nanorods (BN). TiO2 films (∼400 nm) were deposited with a semiautomatic immersion system with controlled immersion/withdraw velocity, using titanium isopropoxide as the titania precursor [1]. For BN synthesis and deposition, the solvo-thermal method was used, introducing air annealed TiO2-substrates in the autoclave. The typical bilayer TiO2/BN hetero-junction was 600 nm thick. The synthesized materials (powders and films) were characterized by X-Ray Diffraction, Scanning Electron Microscopy, and UV-Visible Spectroscopy. Anatase was the crystalline phase of TiO2, while bismuth sulfide nanotubes show a diffraction pattern characteristic of bismuthinite distorted by the preferential growth of some planes [2-4]. The optoelectronic characterization of TiO2/NB hetero-junctions was compared with hetero-junctions obtained by sensitizing TiO2 with chemically deposited bismuth sulfide films. Bismuth sulfide nanowires are 2µm long and 70nm wide (aspect ratio L/D = 43), while chemically deposited bismuth sulfide have L/D = 1, therefore the effect of particle size evaluation and geometry in the photosensitization phenomena will be discussed in the context of new materials for solar-cells applications. (Full text)

Band offset in zinc oxy-sulfide/cubic-tin sulfide interface from X-ray photoelectron spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Sanal, K.C.; Nair, P.K.; Nair, M.T.S., E-mail: mtsn@ier.unam.mx

2017-02-28

Highlights: • Zinc oxy-sulfide thin films, 175–240 nm, deposited by rf-sputtering from targets of ZnO + ZnS. • Oxygen content in thin films is enhanced 3–4 times compared with that in ZnO:ZnS targets. • Thin film ZnO{sub x}S{sub 1−x} with x = 0.88–0.27 and optical band gap 2.8–3.2 eV is suitable for solar cells. • The conduction band offset with SnS of cubic structure studied by XPS are +0.41 to −0.28 eV. - Abstract: Zinc oxy-sulfide, ZnO{sub x}S{sub 1−x}, has been found to provide better band alignment in thin film solar cells of tin sulfide of orthorhombic crystalline structure. Here we examine ZnO{sub x}S{sub 1−x}/SnS-CUB interface, in which the ZnO{sub x}S{sub 1−x} thin film was deposited by radio frequency (rf) magnetron sputtering on SnS thin film of cubic (CUB) crystalline structure with a band gap (E{sub g}) of 1.72 eV, obtained via chemical deposition. X-ray photoelectron spectroscopy provides the valence band maxima of the materials and hence places the conduction band offset of 0.41 eV for SnS-CUB/ZnO{sub 0.27}S{sub 0.73} and −0.28 eV for SnS-CUB/ZnO{sub 0.88}S{sub 0.12} interfaces. Thin films of ZnO{sub x}S{sub 1−x} with 175–240 nm in thickness were deposited from targets prepared with different ZnO to ZnS molar ratios. With the target of molar ratio of 1:13.4, the thin films are of composition ZnO{sub 0.27}S{sub 0.73} with hexagonal crystalline structure and with that of 1:1.7 ratio, it is ZnO{sub 0.88}S{sub 0.12}. The optical band gap of the ZnO{sub x}S{sub 1−x} thin films varies from 2.90 eV to 3.21 eV as the sulfur to zinc ratio in the film increases from 0.12:1 to 0.73:1 as determined from X-ray diffraction patterns. Thus, band offsets sought for absorber materials and zinc oxy-sulfide in solar cells may be achieved through a choice of ZnO:ZnS ratio in the sputtering target.

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......, forming a cohesive whitish veil at the oxic-anoxic interface. Bacteria attached to the veil kept rotating and adapted their stalk lengths dynamically to changing oxygen concentrations. The joint action of rotating bacteria on the veil induced a homogeneous water flow from the oxic water region toward...

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

2015-10-23

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.

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.

The origin and isotopic composition of dissolved sulfide in groundwater from carbonate aquifers in Florida and Texas

International Nuclear Information System (INIS)

Rye, R.O.; Back, W.; Hanshaw, B.B.; Rightmire, C.T.; Pearson, F.J. Jr.

1981-01-01

The delta 34 S values of dissolved sulfide and the sulfur isotope fractionations between dissolved sulfide and sulfate species in Floridan ground water generally correlate with dissolved sulfate concentrations which are related to flow patterns and residence time within the aquifer. The dissolved sulfide derives from the slow in situ biogenic reduction of sulfate dissolved from sedimentary gypsum in the aquifer. In areas where the water is oldest, the dissolved sulfide has apparently attained isotopic equilibrium with the dissolved sulfate at the temperature of the system. This approach to equilibrium reflects an extremely slow reduction rate of the dissolved sulfate by bacteria; this slow rate probably results from very low concentrations of organic matter in the aquifer. In the reducing part of the Edwards aquifer, Texas, there is a general down-gradient increase in both dissolved sulfide and sulfate concentrations, but neither the delta 34 S values of sulfide nor the sulfide-sulfate isotope fractionation correlates with the ground-water flow pattern. The dissolved sulfide species appear to be derived primarily from biogenic reduction of sulfate ions whose source is gypsum dissolution although upgradient diffusion of H 2 S gas from deeper oil field brines may be important in places. (author)

Variability of Fe isotope compositions of hydrothermal sulfides and oxidation products at mid-ocean ridges

Science.gov (United States)

Li, Xiaohu; Wang, Jianqiang; Chu, Fengyou; Wang, Hao; Li, Zhenggang; Yu, Xing; Bi, Dongwei; He, Yongsheng

2018-04-01

Significant Fe isotopic fractionation occurs during the precipitation and oxidative weathering of modern seafloor hydrothermal sulfides, which has an important impact on the cycling of Fe isotopes in the ocean. This study reports the Fe-isotope compositions of whole-rock sulfides and single-mineral pyrite collected from hydrothermal fields at the South Mid-Atlantic Ridge (SMAR) and the East Pacific Rise (EPR) and discusses the impacts of precipitation and late-stage oxidative weathering of sulfide minerals on Fe isotopic fractionation. The results show large variation in the Fe-isotope compositions of the sulfides from the different hydrothermal fields on the mid-oceanic ridges, indicating that relatively significant isotope fractionation occurs during the sulfide precipitation and oxidative weathering processes. The Fe-isotope compositions of the sulfides from the study area at the SMAR vary across a relatively small range, with an average value of 0.01‰. This Fe-isotope composition is similar to the Fe-isotope composition of mid-oceanic ridge basalt, which suggests that Fe was mainly leached from basalt. In contrast, the Fe-isotope composition of the sulfides from the study area at the EPR are significantly enriched in light Fe isotopes (average value - 1.63‰), mainly due to the kinetic fractionation during the rapid precipitation process of hydrothermal sulfide. In addition, the pyrite from different hydrothermal fields is enriched in light Fe isotopes, which is consistent with the phenomenon in which light Fe isotopes are preferentially enriched during the precipitation of pyrite. The red oxides have the heaviest Fe-isotope compositions (up to 0.80‰), indicating that heavy Fe isotopes are preferentially enriched in the oxidation product during the late-stage oxidation process. The data obtained from this study and previous studies show a significant difference between the Fe-isotope compositions of the sulfides from the SMAR and EPR. The relatively heavy

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

Microaeration reduces hydrogen sulfide in biogas

Science.gov (United States)

Although there are a variety of biological and chemical treatments for removal of hydrogen sulfide (H2S) from biogas, all require some level of chemical or water inputs and maintenance. In practice, managing biogas H2S remains a significant challenge for agricultural digesters where labor and opera...

Effect of particle-particle shearing on the bioleaching of sulfide minerals.

Science.gov (United States)

Chong, N; Karamanev, D G; Margaritis, A

2002-11-05

The biological leaching of sulfide minerals, used for the production of gold, copper, zinc, cobalt, and other metals, is very often carried out in slurry bioreactors, where the shearing between sulfide particles is intensive. In order to be able to improve the efficiency of the bioleaching, it is of significant importance to know the effect of particle shearing on the rate of leaching. The recently proposed concept of ore immobilization allowed us to study the effect of particle shearing on the rate of sulfide (pyrite) leaching by Thiobacillus ferrooxidans. Using this concept, we designed two very similar bioreactors, the main difference between which was the presence and absence of particle-particle shearing. It was shown that when the oxygen mass transfer was not the rate-limiting step, the rate of bioleaching in the frictionless bioreactor was 2.5 times higher than that in a bioreactor with particle friction (shearing). The concentration of free suspended cells in the frictionless bioreactor was by orders of magnitude lower than that in the frictional bioreactor, which showed that particle friction strongly reduces the microbial attachment to sulfide surface, which, in turn, reduces the rate of bioleaching. Surprisingly, it was found that formation of a layer of insoluble iron salts on the surface of sulfide particles is much slower under shearless conditions than in the presence of particle-particle shearing. This was explained by the effect of particle friction on liquid-solid mass transfer rate. The results of this study show that reduction of the particle friction during bioleaching of sulfide minerals can bring important advantages not only by increasing significantly the bioleaching rate, but also by increasing the rate of gas-liquid oxygen mass transfer, reducing the formation of iron precipitates and reducing the energy consumption. One of the efficient methods for reduction of particle friction is ore immobilization in a porous matrix. Copyright 2002

Occupationally related hydrogen sulfide deaths in the United States from 1984 to 1994.

Science.gov (United States)

Fuller, D C; Suruda, A J

2000-09-01

Alice Hamilton described fatal work injuries from acute hydrogen sulfide poisonings in 1925 in her book Industrial Poisons in the United States. There is no unique code for H2S poisoning in the International Classification of Diseases, 9th Revision; therefore, these deaths cannot be identified easily from vital records. We reviewed US Occupational Safety and Health Administration (OSHA) investigation records for the period 1984 to 1994 for mention of hazardous substance 1480 (hydrogen sulfide). There were 80 fatalities from hydrogen sulfide in 57 incidents, with 19 fatalities and 36 injuries among coworkers attempting to rescue fallen workers. Only 17% of the deaths were at workplaces covered by collective bargaining agreements. OSHA issued citations for violation of respiratory protection and confined space standards in 60% of the fatalities. The use of hydrogen sulfide detection equipment, air-supplied respirators, and confined space safety training would have prevented most of the fatalities.

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. Copyright © 2015 Elsevier Ltd. All rights reserved.

Formation of mercury sulfide from Hg(II)−thiolate complexes in natural organic matter

Science.gov (United States)

Alain Manceau,; Cyprien Lemouchi,; Mironel Enescu,; Anne-Claire Gaillot,; Martine Lanson,; Valerie Magnin,; Pieter Glatzel,; Poulin, Brett; Ryan, Joseph N.; Aiken, George R.; Isabelle Gautier-Lunea,; Kathryn L. Nagy,

2015-01-01

Methylmercury is the environmental form of neurotoxic mercury that is biomagnified in the food chain. Methylation rates are reduced when the metal is sequestered in crystalline mercury sulfides or bound to thiol groups in macromolecular natural organic matter. Mercury sulfide minerals are known to nucleate in anoxic zones, by reaction of the thiol-bound mercury with biogenic sulfide, but not in oxic environments. We present experimental evidence that mercury sulfide forms from thiol-bound mercury alone in aqueous dark systems in contact with air. The maximum amount of nanoparticulate mercury sulfide relative to thiol-bound mercury obtained by reacting dissolved mercury and soil organic matter matches that detected in the organic horizon of a contaminated soil situated downstream from Oak Ridge, TN, in the United States. The nearly identical ratios of the two forms of mercury in field and experimental systems suggest a common reaction mechanism for nucleating the mineral. We identified a chemical reaction mechanism that is thermodynamically favorable in which thiol-bound mercury polymerizes to mercury–sulfur clusters. The clusters form by elimination of sulfur from the thiol complexes via breaking of mercury–sulfur bonds as in an alkylation reaction. Addition of sulfide is not required. This nucleation mechanism provides one explanation for how mercury may be immobilized, and eventually sequestered, in oxygenated surface environments.

Determination of Hydrogen Sulfide in Fermentation Broths Containing SO21

Science.gov (United States)

Acree, T. E.; Sonoff, Elisabeth P.; Splittstoesser, D. F.

1971-01-01

A procedure for the determination of hydrogen sulfide in fermentation broths containing up to 100 μg of SO2 per ml is described. The method involves the sparging of H2S from the broth into a cadmium hydroxide absorption solution, the formation of methylene blue from the absorbed sulfide, and the measuring of this color spectrophotometrically. The use of cadmium hydroxide instead of zinc acetate, the common absorbent, substantially reduced the interference of SO2 with the analysis. PMID:5111300

Reaction between vanadium trichloride oxide and hydrogen sulfide

International Nuclear Information System (INIS)

Yajima, Akimasa; Matsuzaki, Ryoko; Saeki, Yuzo

1978-01-01

The details of the reaction between vanadium trichloride oxide and hydrogen sulfide were examined at 20 and 60 0 C. The main products by the reaction were vanadium dichloride oxide, sulfur, and hydrogen chloride. In addition to these products, small amounts of vanadium trichloride, vanadium tetrachloride, disulfur dichloride, and sulfur dioxide were formed. The formations of the above-mentioned reaction products can be explained as follows: The first stage is the reaction between vanadium trichloride oxide and hydrogen sulfide, 2VOCl 3 (l) + H 2 S(g)→2VOCl 2 (s) + S(s) + 2HCl(g). Then the resulting sulfur reacts with the unreacted vanadium trichloride oxide, 2VOCl 3 (l) + 2S(s)→2VOCl 2 (s) + S 2 Cl 2 (l). The resulting disulfur dichloride subsequently reacts with the unreacted vanadium trichloride oxide, 2VOCl 3 (l) + S 2 Cl 2 (l)→2VCl 4 (l) + S(s) + SO 2 (g). The resulting vanadium tetrachloride reacts with the sulfur formed during the reaction, 2VCl 4 (l) + 2S(s)→2VCl 3 (s) + S 2 Cl 2 (l), and also reacts with hydrogen sulfide, 2VCl 4 (l) + H 2 S(g)→2VCl 3 (s) + S(s) + 2HCl(g). (auth.)

Disguised as a Sulfate Reducer: Growth of the Deltaproteobacterium Desulfurivibrio alkaliphilus by Sulfide Oxidation with Nitrate.

Science.gov (United States)

Thorup, Casper; Schramm, Andreas; Findlay, Alyssa J; Finster, Kai W; Schreiber, Lars

2017-07-18

This study demonstrates that the deltaproteobacterium Desulfurivibrio alkaliphilus can grow chemolithotrophically by coupling sulfide oxidation to the dissimilatory reduction of nitrate and nitrite to ammonium. Key genes of known sulfide oxidation pathways are absent from the genome of D. alkaliphilus Instead, the genome contains all of the genes necessary for sulfate reduction, including a gene for a reductive-type dissimilatory bisulfite reductase (DSR). Despite this, growth by sulfate reduction was not observed. Transcriptomic analysis revealed a very high expression level of sulfate-reduction genes during growth by sulfide oxidation, while inhibition experiments with molybdate pointed to elemental sulfur/polysulfides as intermediates. Consequently, we propose that D. alkaliphilus initially oxidizes sulfide to elemental sulfur, which is then either disproportionated, or oxidized by a reversal of the sulfate reduction pathway. This is the first study providing evidence that a reductive-type DSR is involved in a sulfide oxidation pathway. Transcriptome sequencing further suggests that nitrate reduction to ammonium is performed by a novel type of periplasmic nitrate reductase and an unusual membrane-anchored nitrite reductase. IMPORTANCE Sulfide oxidation and sulfate reduction, the two major branches of the sulfur cycle, are usually ascribed to distinct sets of microbes with distinct diagnostic genes. Here we show a more complex picture, as D. alkaliphilus , with the genomic setup of a sulfate reducer, grows by sulfide oxidation. The high expression of genes typically involved in the sulfate reduction pathway suggests that these genes, including the reductive-type dissimilatory bisulfite reductases, are also involved in as-yet-unresolved sulfide oxidation pathways. Finally, D. alkaliphilus is closely related to cable bacteria, which grow by electrogenic sulfide oxidation. Since there are no pure cultures of cable bacteria, D. alkaliphilus may represent an

Evaluation of methods for monitoring air concentrations of hydrogen sulfide

Directory of Open Access Journals (Sweden)

Katarzyna Janoszka

2013-06-01

Full Text Available The development of different branches of industry and a growing fossil fuels mining results in a considerable emission of by-products. Major air pollutants are: CO, CO₂, SO₂, SO₃, H₂S, nitrogen oxides, as well as compounds of an organic origin. The main aspects of this paper is to review and evaluate methods used for monitoring of hydrogen sulfide in the air. Different instrumental techniques were discussed, electrochemical, chromatographic and spectrophotometric (wet and dry, to select the method most suitable for monitoring low levels of hydrogen sulfide, close to its odor threshold. Based on the literature review the method for H₂S determination in the air, involving absorption in aqueous zinc acetate and reaction with N,N-dimethylo-p-phenylodiamine and FeCl₃, has been selected and preliminary verified. The adopted method allows for routine measurements of low concentration of hydrogen sulfide, close to its odor threshold in workplaces and ambient air. Med Pr 2013;64(3:449–454

Hydrogen sulfide concentration in Beaver Dam Creek

International Nuclear Information System (INIS)

Kiser, D.L.

1979-01-01

Concentration-time profiles calculated with LODIPS for various hypothetical releases of hydrogen sulfide from the heavy water extraction facility predict lethal conditions for swamp fish from releases as small as 568 kg discharged over a period of 30 minutes or from releases of 1818 kg discharged over a period of 6 hours or less. The necessary volatilization and oxidation coefficients for LODIPS were derived from field measurements following planned releases of H 2 S. Upsets in the operation of the wastewater strippers in the Girdler-Sulfide (GS) heavy water extraction facility in D Area have released significant amounts of dissolved H 2 S to Beaver Dam Creek. Because H 2 S is toxic to fish in concentrations as low as 1 mg/liter, the downstream environmental impact of H 2 S releases from D Area was evaluated

Inhibition effects of protein-conjugated amorphous zinc sulfide nanoparticles on tumor cells growth

International Nuclear Information System (INIS)

Cao Ying; Wang Huajie; Cao Cui; Sun Yuanyuan; Yang Lin; Wang Baoqing; Zhou Jianguo

2011-01-01

In this article, a facile and environmentally friendly method was applied to fabricate BSA-conjugated amorphous zinc sulfide (ZnS) nanoparticles using bovine serum albumin (BSA) as the matrix. Transmission electron microscopy analysis indicated that the stable and well-dispersed nanoparticles with the diameter of 15.9 ± 2.1 nm were successfully prepared. The energy dispersive X-ray, X-ray powder diffraction, Fourier transform infrared spectrograph, high resolution transmission electron microscope, and selected area electron diffraction measurements showed that the obtained nanoparticles had the amorphous structure and the coordination occurred between zinc sulfide surfaces and BSA in the nanoparticles. In addition, the inhibition effects of BSA-conjugated amorphous zinc sulfide nanoparticles on tumor cells growth were described in detail by cell viability analysis, optical and electron microscopy methods. The results showed that BSA-conjugated amorphous zinc sulfide nanoparticles could inhibit the metabolism and proliferation of human hepatocellular carcinoma cells, and the inhibition was dose dependent. The half maximal inhibitory concentration (IC50) was 0.36 mg/mL. Overall, this study suggested that BSA-conjugated amorphous zinc sulfide nanoparticles had the application potential as cytostatic agents and BSA in the nanoparticles could provide the modifiable site for the nanoparticles to improve their bioactivity or to endow them with the target function.

The effect of tin sulfide quantum dots size on photocatalytic and photovoltaic performance

Energy Technology Data Exchange (ETDEWEB)

Cheraghizade, Mohsen [Young Researchers and Elite Club, Ahvaz Branch, Islamic Azad University, Ahvaz (Iran, Islamic Republic of); Jamali-Sheini, Farid, E-mail: faridjamali@iauahvaz.ac.ir [Advanced Surface Engineering and Nano Materials Research Center, Department of Physics, Ahvaz Branch, Islamic Azad University, Ahvaz (Iran, Islamic Republic of); Yousefi, Ramin [Department of Physics, Masjed-Soleiman Branch, Islamic Azad University (I.A.U), Masjed-Soleiman (Iran, Islamic Republic of); Niknia, Farhad [Young Researchers and Elite Club, Ahvaz Branch, Islamic Azad University, Ahvaz (Iran, Islamic Republic of); Mahmoudian, Mohammad Reza [Department of Chemistry, Shahid Sherafat, University of Farhangian, 15916, Tehran (Iran, Islamic Republic of); Sookhakian, Mehran [Centre for Ionic Liquids, Department of Chemistry, Faculty of Science, University of Malaya, Kuala Lumpur 50603 (Malaysia)

2017-07-01

In the current study, tin sulfide Quantum Dots (QDs) was successfully synthesized through sonochemical synthesis method by applying sonication times of 10, 15, and 20 min. Structural studies showed an orthorhombic phase of SnS and Sn{sub 2}S{sub 3}, and hexagonal phase of SnS{sub 2}. The particle size of tin sulfide QDs prepared through sonication time of 20 min was smaller than other QDs. According to TEM images, an increase in sonication time resulted in smaller spherical shaped particles. According to the results of Raman studies, five Raman bands and a shift towards the lower frequencies were observed by enhancing the sonication time. Based on the outcomes of photocatalytic activity, higher this property was observed for tin sulfide QDs, which are prepared through longer sonication time. Solar cell devices manufactured using tin sulfide QDs have a greater performance for the samples with more sonication time. Considering the obtained outcomes, the sonication time seems probable to be a factor affecting synthesis process of SnS QDs as well as its optical and electrical, photocatalytic, and photovoltaic conversion features. - Highlights: • Tin sulfide quantum dots (QDs) synthesized using a sonication method. • The sonication time was selected as a synthesis parameter. • The photocatalytic and photovoltaic performance were depended on synthesis parameter.

The effect of tin sulfide quantum dots size on photocatalytic and photovoltaic performance

International Nuclear Information System (INIS)

Cheraghizade, Mohsen; Jamali-Sheini, Farid; Yousefi, Ramin; Niknia, Farhad; Mahmoudian, Mohammad Reza; Sookhakian, Mehran

2017-01-01

In the current study, tin sulfide Quantum Dots (QDs) was successfully synthesized through sonochemical synthesis method by applying sonication times of 10, 15, and 20 min. Structural studies showed an orthorhombic phase of SnS and Sn_2S_3, and hexagonal phase of SnS_2. The particle size of tin sulfide QDs prepared through sonication time of 20 min was smaller than other QDs. According to TEM images, an increase in sonication time resulted in smaller spherical shaped particles. According to the results of Raman studies, five Raman bands and a shift towards the lower frequencies were observed by enhancing the sonication time. Based on the outcomes of photocatalytic activity, higher this property was observed for tin sulfide QDs, which are prepared through longer sonication time. Solar cell devices manufactured using tin sulfide QDs have a greater performance for the samples with more sonication time. Considering the obtained outcomes, the sonication time seems probable to be a factor affecting synthesis process of SnS QDs as well as its optical and electrical, photocatalytic, and photovoltaic conversion features. - Highlights: • Tin sulfide quantum dots (QDs) synthesized using a sonication method. • The sonication time was selected as a synthesis parameter. • The photocatalytic and photovoltaic performance were depended on synthesis parameter.

Rocks Whose Compositions are Determined by Flow Differentiation of Olivine- and Sulfide Droplet-Laden Magma: the Jinchuan Story

Science.gov (United States)

Li, C.; Ripley, E. M.; de Waal, S. A.; Xu, Z.

2002-12-01

The Jinchuan intrusion in western China is an elongated, deeply-dipping dyke-like body of dominantly olivine-rich ultramafic rocks of high magnesium basaltic magma. It hosts the second largest Ni-Cu sulfide deposit in the world. More than 500 million tones of sulfide ore grading 1.2 percent Ni and 0.7 percent Cu occur mostly as next-textured and disseminated sulfide (pyrrhotite, pentlendite and chalcopyrite) with cumulus olivine in about half of the rocks of the intrusion. Based on different petrological zonations, the Jinchuan intrusion is further divided into three segments: eastern, central and western segments. The central segment is characterized by concentric enrichments of cumulus olivine and sulfide, whereas the eastern and western segments are characterized by the increase of both cumulus olivine and sulfide toward the footwall. The forsterite contents of fresh olivine from different segments are similar and vary between 82 and 86 mole percent. The small range of olivine compositional variation corresponds to less than 6 percent of fractional crystallization. Mass balance calculations based on sulfide solubility in basaltic magma indicate that the volume of the parental magma of the sulfide is many times larger than that which is currently represented in the intrusion. Large amounts of cumulus olivine (more than 40 weight percent) in the marginal samples and high concentrations of sulfide in the intrusion are consistent with an interpretation that the Jinchuan intrusion was formed by olivine- and sulfide droplet-laden magma ascending through a subvertical conduit to a higher level. Differentiation processes of the olivine- and sulfide droplet-laden magma varied in different parts of the conduit. Sub-vertical flow differentiation controlled the central segment of the conduit, resulting in further enrichment of olivine crystals and sulfide droplets in the conduit center. In contrast, sub-lateral flow and gravitational differentiation dominated in the eastern

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.

Dechlorination of chloropicrin and 1,3-dichloropropene by hydrogen sulfide species: redox and nucleophilic substitution reactions.

Science.gov (United States)

Zheng, Wei; Yates, Scott R; Papiernik, Sharon K; Guo, Mingxin; Gan, Jianying

2006-03-22

The chlorinated fumigants chloropicrin (trichloronitromethane) and 1,3-dichloropropene (1,3-D) are extensively used in agricultural production for the control of soilborne pests. The reaction of these two fumigants with hydrogen sulfide species (H2S and HS-) was examined in well-defined anoxic aqueous solutions. Chloropicrin underwent an extremely rapid redox reaction in the hydrogen sulfide solution. Transformation products indicated reductive dechlorination of chloropicrin by hydrogen sulfide species to produce dichloro- and chloronitromethane. The transformation of chloropicrin in hydrogen sulfide solution significantly increased with increasing pH, indicating that H2S is less reactive toward chloropicrin than HS- is. For both 1,3-D isomers, kinetics and transformation products analysis revealed that the reaction between 1,3-D and hydrogen sulfide species is an S(N)2 nucleophilic substitution process, in which the chlorine at C3 of 1,3-D is substituted by the sulfur nucleophile to form corresponding mercaptans. The 50% disappearance time (DT50) of 1,3-D decreased with increasing hydrogen sulfide species concentration at a constant pH. Transformation of 1,3-D was more rapid at high pH, suggesting that the reactivity of hydrogen sulfide species in the experimental system stems primarily from HS-. Because of the relatively low smell threshold values and potential environmental persistence of organic sulfur products yielded by the reaction of 1,3-D and HS-, the effects of reduced sulfide species should be considered in the development of alternative fumigation practices, especially in the integrated application of sulfur-containing fertilizers.

Intercalation of gaseous thiols and sulfides into Ag+ ion-exchanged aluminum dihydrogen triphosphate.

Science.gov (United States)

Hayashi, Aki; Saimen, Hiroki; Watanabe, Nobuaki; Kimura, Hitomi; Kobayashi, Ayumi; Nakayama, Hirokazu; Tsuhako, Mitsutomo

2005-08-02

Ag(+) ion-exchanged layered aluminum dihydrogen triphosphate (AlP) with the interlayer distance of 0.85 nm was synthesized by the ion-exchange of proton in triphosphate with Ag(+) ion. The amount of exchanged Ag(+) ion depended on the concentration of AgNO(3) aqueous solution. Ag(+) ion-exchanged AlP adsorbed gaseous thiols and sulfides into the interlayer region. The adsorption amounts of thiols were more than those of sulfides, thiols with one mercapto group > thiol with two mercapto groups > sulfides, and depended on the amount of exchanged Ag(+) ion in the interlayer region. The thiols with one mercapto group were intercalated to expand the interlayer distance of Ag(+) ion-exchanged AlP, whereas there was no expansion in the adsorption of sulfide. In the case of thiol with two mercapto groups, there was observed contraction of the interlayer distance through the bridging with Ag(+) ions of the upper and lower sides of the interlayer region.

Support Effect in Hydrodesulfurization over Ruthenium Sulfide

Czech Academy of Sciences Publication Activity Database

Gulková, Daniela; Kaluža, Luděk; Vít, Zdeněk; Zdražil, Miroslav

2009-01-01

Roč. 51, č. 2 (2009), s. 146-149 ISSN 1337-7027 R&D Projects: GA ČR GA104/06/0705 Institutional research plan: CEZ:AV0Z40720504 Keywords : ruthenium sulfide * hydrodesulfurization * support effect Subject RIV: CC - Organic Chemistry

Reaction of Hydrogen Sulfide with Oxygen in the Presence ofSulfite

Energy Technology Data Exchange (ETDEWEB)

Weres, Oleh; Tsao, Leon

1983-01-01

Commonly, abatement of hydrogen sulfide emissions from a geothermal powerplant requires that hydrogen sulfide dissolved in the cooling water be eliminated by chemical reaction. Oxidation by atmospheric oxygen is the preferred reaction, but requires a suitable catalyst. Nickel is the most potent and thereby cheapest catalyst for this purpose. One Mg/L nickel in the cooling water would allow 99% removal of hydrogen sulfide to be attained. A major drawback of catalytic air oxidation is that colloidal sulfur is a major reaction product; this causes rapid sludge accumulation and deposition of sulfur scale. The authors studied the kinetics and product distribution of the reaction of hydrogen sulfide with oxygen, catalyzed by nickel. Adding sodium sulfite to the solution completely suppresses formation of colloidal sulfur by converting it to thiosulfate. The oxidation reaction is an autocatalytic, free radical chain reaction. A rate expression for this reaction and a detailed reaction mechanism were developed. Nickel catalyzes the chain initiation step, and polysulfidoradical ions propagate the chains. Several complexes of iron and cobalt were also studied. Iron citrate and iron N-hydroxyEDT are the most effective iron based catalysts. Uncomplexed cobalt is as effective as nickel, but forms a precipitate of cobalt oxysulfide and is too expensive for practical use.

Reaction of hydrogen sulfide with oxygen in the presence of sulfite

Energy Technology Data Exchange (ETDEWEB)

Weres, O.; Tsao, L.

1983-01-14

Commonly, abatement of hydrogen sulfide emission from a geothermal powerplant requires that hydrogen sulfide dissolved in the cooling water be eliminated by chemical reaction. Oxidation by atmospheric oxygen is the preferred reaction, but requires a suitable catalyst. Nickel is the most potent and thereby cheapest catalyst for this purpose. One mg/L nickel in the cooling water would allow 99% removal of hydrogen sulfide to be attained. A major drawback of catalytic air oxidation is that colloidal sulfur is a major reaction product; this causes rapid sludge accumulation and deposition of sulfur scale. We studied the kinetics and product distribution of the reaction of hydrogen sulfide with oxygen, catalyzed by nickel. Adding sodium sulfite to the solution completely suppresses formation of colloidal sulfur by converting it to thiosulfate. The oxidation reaction is an autocatalytic, free radical chain reaction. A rate expression for this reaction and a detailed reaction mechanism were developed. Nickel catalyzes the chain initiation step, and polysulfidoradical ions propagate the chains. Several complexes of iron and cobalt were also studied. Iron citrate and iron N-hydroxyEDTA are the most effective iron based catalysts. Uncomplexed cobalt is as effective as nickel, but forms a precipitate of cobalt oxysulfide and is too expensive for practical use. 33 figures, 9 tables.

Magnetic MoS2 on multiwalled carbon nanotubes for sulfide sensing.

Science.gov (United States)

Li, Chunxiang; Zhang, Dan; Wang, Jiankang; Hu, Pingan; Jiang, Zhaohua

2017-07-04

A novel hybrid metallic cobalt insided in multiwalled carbon nanotubles/molybdenum disulfide (Co@CNT/MoS 2 ) modified glass carbon electrode (GCE) was fabricated with a adhesive of Nafion suspension and used as chemical sensors for sulfide detection. Single-layered MoS 2 was coated on CNTs through magnetic traction force between paramagnetic monolayer MoS 2 and Co particles in CNTs. Co particles faciliated the collection of paramagnetic monolayer MoS 2 exfoliated from bulk MoS 2 in solution. Amperometric analysis, cycle voltammetry, cathodic stripping analysis and linear sweep voltammetry results showed the Co@CNT/MoS 2 modified GCE exhibited excellent electrochemical activity to sulfide in buffer solutions, but amperometric analysis was found to be more sensitive than the other methods. The amperometric response result indicated the Co@CNT/MoS 2 -modified GCE electrode was an excellent electrochemical sensor for detecting S 2- with a detection limit of 7.6 nM and sensitivity of 0.23 mA/μM. The proposed electrode was used for the determination of sulfide levels in hydrogen sulfide-pretreated fruits, and the method was also verified with recovery studies. Copyright © 2017 Elsevier B.V. All rights reserved.

Reactive Transport Modeling Investigation of High Dissolved Sulfide Concentrations in Sedimentary Basin Rocks

Science.gov (United States)

Xie, M.; Mayer, U. K.; MacQuarrie, K. T. B.

2017-12-01

Water with total dissolved sulfide in excess of 1 mmol L-1is widely found in groundwater at intermediate depths in sedimentary basins, including regions of the Michigan basin in southeastern Ontario, Canada. Conversely, at deeper and shallower depths, relatively low total dissolved sulfide concentrations have been reported. The mechanisms responsible for the occurrence of these brackish sulfide-containing waters are not fully understood. Anaerobic microbial sulfate reduction is a common process resulting in the formation of high sulfide concentrations. Sulfate reduction rates depend on many factors including the concentration of sulfate, the abundance of organic substances, redox conditions, temperature, salinity and the species of sulfate reducing bacteria (SRB). A sedimentary basin-specific conceptual model considering the effect of salinity on the rate of sulfate reduction was developed and implemented in the reactive transport model MIN3P-THCm. Generic 2D basin-scale simulations were undertaken to provide a potential explanation for the dissolved sulfide distribution observed in the Michigan basin. The model is 440 km in the horizontal dimension and 4 km in depth, and contains fourteen sedimentary rock units including shales, sandstones, limestones, dolostone and evaporites. The main processes considered are non-isothermal density dependent flow, kinetically-controlled mineral dissolution/precipitation and its feedback on hydraulic properties, cation exchange, redox reactions, biogenic sulfate reduction, and hydromechanical coupling due to glaciation-deglaciation events. Two scenarios were investigated focusing on conditions during an interglacial period and the transient evolution during a glaciation-deglaciation cycle. Inter-glaciation simulations illustrate that the presence of high salinity brines strongly suppress biogenic sulfate reduction. The transient simulations show that glaciation-deglaciation cycles can have an impact on the maximum depth of

Characterization and Expression of the Lucina pectinata Oxygen and Sulfide Binding Hemoglobin Genes

Science.gov (United States)

López-Garriga, Juan; Cadilla, Carmen L.

2016-01-01

The clam Lucina pectinata lives in sulfide-rich muds and houses intracellular symbiotic bacteria that need to be supplied with hydrogen sulfide and oxygen. This clam possesses three hemoglobins: hemoglobin I (HbI), a sulfide-reactive protein, and hemoglobin II (HbII) and III (HbIII), which are oxygen-reactive. We characterized the complete gene sequence and promoter regions for the oxygen reactive hemoglobins and the partial structure and promoters of the HbI gene from Lucina pectinata. We show that HbI has two mRNA variants, where the 5’end had either a sequence of 96 bp (long variant) or 37 bp (short variant). The gene structure of the oxygen reactive Hbs is defined by having 4-exons/3-introns with conservation of intron location at B12.2 and G7.0 and the presence of pre-coding introns, while the partial gene structure of HbI has the same intron conservation but appears to have a 5-exon/ 4-intron structure. A search for putative transcription factor binding sites (TFBSs) was done with the promoters for HbII, HbIII, HbI short and HbI long. The HbII, HbIII and HbI long promoters showed similar predicted TFBSs. We also characterized MITE-like elements in the HbI and HbII gene promoters and intronic regions that are similar to sequences found in other mollusk genomes. The gene expression levels of the clam Hbs, from sulfide-rich and sulfide-poor environments showed a significant decrease of expression in the symbiont-containing tissue for those clams in a sulfide-poor environment, suggesting that the sulfide concentration may be involved in the regulation of these proteins. Gene expression evaluation of the two HbI mRNA variants indicated that the longer variant is expressed at higher levels than the shorter variant in both environments. PMID:26824233

Sulfide-inhibition of mitochondrial respiration at very low oxygen concentrations.

Science.gov (United States)

Matallo, J; Vogt, J; McCook, O; Wachter, U; Tillmans, F; Groeger, M; Szabo, C; Georgieff, M; Radermacher, P; Calzia, E

2014-09-15

Our aim was to study the ability of an immortalized cell line (AMJ2-C11) to sustain aerobic cell respiration at decreasing oxygen concentrations under continuous sulfide exposure. We assumed that the rate of elimination of sulfide through the pathway linked to the mitochondrial respiratory chain and therefore operating under aerobic conditions, should decrease with limiting oxygen concentrations. Thus, sulfide's inhibition of cellular respiration would occur faster under continuous sulfide exposure when the oxygen concentration is in the very low range. The experiments were performed with an O2K-oxygraph (Oroboros Instruments) by suspending 0.5-1×10(6) cells in 2 ml of continuously stirred respiration medium at 37 °C and calculating the oxygen flux (JO2) as the negative derivative of the oxygen concentration in the medium. The cells were studied in two different metabolic states, namely under normal physiologic respiration (1) and after uncoupling of mitochondrial respiration (2). Oxygen concentration was controlled by means of a titration-injection pump, resulting in average concentration values of 0.73±0.05 μM, 3.1±0.2 μM, and 6.2±0.2 μM. Simultaneously we injected a 2 mM Na2S solution at a continuous rate of 10 μl/s in order to quantify the titration-time required to reduce the JO2 to 50% of the initial respiratory activity. Under the lowest oxygen concentration this effect was achieved after 3.5 [0.3;3.5] and 11.7 [6.2;21.2]min in the uncoupled and coupled state, respectively. This time was statistically significantly shorter when compared to the intermediate and the highest O2 concentrations tested, which yielded values of 24.6 [15.5;28.1]min (coupled) and 35.9 [27.4;59.2]min (uncoupled), as well as 42.4 [27.5;42.4]min (coupled) and 51.5 [46.4;51.7]min (uncoupled). All data are medians [25%, and 75% percentiles]. Our results confirm that the onset of inhibition of cell respiration by sulfide occurs earlier under a continuous exposure when approaching

New cyclic sulfides extracted from Allium sativum: garlicnins P, J2, and Q.

Science.gov (United States)

Nohara, Toshihiro; Ono, Masateru; Nishioka, Naho; Masuda, Fuka; Fujiwara, Yukio; Ikeda, Tsuyoshi; Nakano, Daisuke; Kinjo, Junei

2018-01-01

Two atypical cyclic-type sulfides, garlicnin P (1) and garlicnin J 2 (2), and one thiabicyclic-type sulfide, garlicnin Q (3), were isolated from the acetone extracts of garlic, Allium sativum, bulbs cultivated in the Kumamoto city area, and their structures characterized. Their production pathways are also discussed.

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...

Cold excitation and determination of hydrogen sulfide by dielectric barrier discharge molecular emission spectrometry.

Science.gov (United States)

Wu, Zhongchen; Jiang, Jie; Li, Na

2015-11-01

A low-temperature microplasma generated in a dielectric barrier discharge (DBD) was used as a radiation source for the excitation of hydrogen sulfide and its determination by molecular emission spectrometry (MES). The excitation/emission chamber was enclosed to eliminate spectral interference from ambient air. The spectral emission lines of hydrogen sulfide were clearly discriminated from the background spectrum, and the emission line at 365.06 nm was selected for parameter optimization and quantitative analysis. The S(2-) ions in aqueous samples were reacted with acid to generate hydrogen sulfide and then determined. The experimental parameters affecting the determination of hydrogen sulfide and S(2-) were optimized. The limits of detection were 1.4 mg m(-3) for H2S and 11.2 mg L(-1) for S(2-). The repeatability of the method was satisfactory, as the RSD values were 2.3% for H2S and 1.8% for S(2-). The enclosed DBD-MES system was demonstrated to be a useful tool for the determination of hydrogen sulfide in gas samples and S(2-) in aqueous samples. Copyright © 2015 Elsevier B.V. All rights reserved.

Hydrothermal synthesis of cobalt sulfide nanotubes: The size control and its application in supercapacitors

Science.gov (United States)

Wan, Houzhao; Ji, Xiao; Jiang, Jianjun; Yu, Jingwen; Miao, Ling; Zhang, Li; Bie, Shaowei; Chen, Haichao; Ruan, Yunjun

2013-12-01

Cobalt sulfide nanotubes are synthesized by hydrothermal method. The precursor is characterized by XRD, FTIR and SEM. We study the influence of temperature on the evolution of this special coarse shape nanostructure and analyze relationship between the sizes of cobalt sulfide nanotubes and the capacitive properties of active materials. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) are used to study the effects of microstructure and morphology of the samples on their capacitance and conductivity. The specific capacitance of cobalt sulfide nanotubes (obtained in 80 °C) electrode exhibits a capacitance of 285 F g-1 at the current density of 0.5 A g-1 as well as rather good cycling stability. Moreover, during the cycling process, the coulombic efficiency remains 99%. The as-prepared cobalt sulfide nanotubes electrode exhibits excellent electrochemical performance as electrode materials for supercapacitors.

Change of sulfide inclusions in steel microalloying with rare earth and alkaline-earth elements

International Nuclear Information System (INIS)

Averin, V.V.; Polonskaya, S.M.; Chistyakov, V.F.

1977-01-01

The conditions for the formation of sulfides in molten and solid iron were determined by considering the thermodynamics of the interaction of sulfur and of oxygen with various components. It was shown in casting of low-carbon steel under a blanket of slag-forming briquettes, calcium of the silicocalcium partly passes to iron and to the sulfide phase. The sulfide inclusions with calcium in rolling become lens-shaped and acquire a greater strength, proportional to the content of calcium, thus ensuring a lesser anisotropy of steel. The change in the shape and the composition of sulfide inclusions effects the fracture of the metal which changes in type from separation along lamellar inclusions to a plastic fracture, i.e., enhances resilience. It is thus noted that rare-earth and alkali-earth elements, in particular, cerium and calcium are promising agents for desulfurating molten iron

Sulfur isotope study of a modern intertidal environment, and the interpretation of ancient sulfides

International Nuclear Information System (INIS)

Chambers, L.A.

1982-01-01

Extensive sulfur isotope distribution data for sulfides precipitated in an intertidal environment show no distinctive features when compared with isotope values for other marine, sedimentary sulfides. The fractionation ranges from α = 1.030 to α = 1.048. The pattern is characteristic for a system essentially open to sulfate, and isotope analyses of interstitial sulfates are corroborative. A population of sulfate-reducing bacteria of the order of 10 9 organisms per cc of interstitial water is indicated. Seasonal variation of the isotope distribution reflects a transient sulfide composition and a bacterial population in which the fractionation effect is indirectly controlled by temperature. The data presented for this modern shallow water environment are at variance with an earlier assessment of isotopic distributions in ancient sulfides which linked shallow water environments with limited fractionation (α =< 1.025) in a closed system. (author)

Sulfur isotope study of a modern intertidal environment, and the interpretation of ancient sulfides

Energy Technology Data Exchange (ETDEWEB)

Chambers, L.A. (Baas Becking Geobiological Lab., Canberra City (Australia))

1982-05-01

Extensive sulfur isotope distribution data for sulfides precipitated in an intertidal environment show no distinctive features when compared with isotope values for other marine, sedimentary sulfides. The fractionation ranges from ..cap alpha.. = 1.030 to ..cap alpha.. = 1.048. The pattern is characteristic for a system essentially open to sulfate, and isotope analyses of interstitial sulfates are corroborative. A population of sulfate-reducing bacteria of the order of 10/sup 9/ organisms per cc of interstitial water is indicated. Seasonal variation of the isotope distribution reflects a transient sulfide composition and a bacterial population in which the fractionation effect is indirectly controlled by temperature. The data presented for this modern shallow water environment are at variance with an earlier assessment of isotopic distributions in ancient sulfides which linked shallow water environments with limited fractionation (..cap alpha.. =< 1.025) in a closed system.

Exploiting fields of gases containing hydrogen-sulfide

Energy Technology Data Exchange (ETDEWEB)

Shevets, V.A.

1980-01-01

The anthology is devoted to problems of geology, hydrogeology, drilling, industrial development, and processing of gas and condensate at the Orenburg Gas-Chemical Complex. Reviews ways to develop the technology for further processing of hydrogen sulfide gas, as well as handling corrosion.

Technetium Reduction and Permanent Sequestration by Abiotic and Biotic Formation of Low-Solubility Sulfide Mineral Phases

Energy Technology Data Exchange (ETDEWEB)

Tratnyek, Paul G. [Oregon Health & Science Univ., Beaverton, OR (United States); Tebo, Bradley M. [Oregon Health & Science Univ., Beaverton, OR (United States); Fan, Dimin [Oregon Health & Science Univ., Beaverton, OR (United States); Anitori, Roberto [Oregon Health & Science Univ., Beaverton, OR (United States); Szecsody, Jim [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Jansik, Danielle [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2015-11-14

One way to minimize the mobility of the Tc^VII oxyanion pertechnetate (TcO₄^-) is to effect reduction under sulfidogenic conditions (generated abiotically by Fe₀ or biotically) to form TcS_x, which is significantly slower to oxidize than Tc^IVO₂. In sediment systems, TcS_x and other precipitates may oxidize more slowly due to oxygen diffusion limitations to these low permeability precipitate zones. In addition, the TcO₄^- reduction rate may be more rapid in the presence of sediment because of additional reductive surface phases. This project aims to provide a fundamental understanding of the feasibility of immobilization of TcO₄^- as TcS_x in the vadose zone or groundwater by application nano zero-valent iron (nZVI), and sulfide or sulfate. Biotic batch experiments have used the sulfate-reducing bacterium (SRB) Desulfotomaculum reducens. The iron sulfide mineral mackinawite was generated under these conditions, while vivianite was formed in nZVI only controls. The sulfide/bacteria-containing system consistently reduced aqueous pertechnetate rapidly (> 95% in the first hour), a rate similar to that for the sulfide-free, nZVI only system. Reduced Tc (aged for 3 months) generated in both SRB/nZVI systems was highly resistant to reoxidation. In reduced samples, Tc was found associated with solid phases containing Fe and S (D. reducens/nZVI) or Fe (nZVI only). Experiments using D. reducens without nZVI provided some additional insights. Firstly, stationary phase cultures were able to slowly reduce pertechnetate. Secondly, addition of pertechnetate at the beginning of cell growth (lag phase) resulted in a faster rate of Tc reduction, possibly indicating a direct (e.g. enzymatic) role for D. reducens in Tc reduction. Abiotic batch experiments were conducted with Na₂S as the sulfide source. Pertechnetate reduction was

The Determination of Hydrogen Sulfide in Stack Gases, Iodometric Titration After Sulfite Removal.

Science.gov (United States)

Robles, E. G.

The determination of hydrogen sulfide in effluents from coal-fired furnaces and incinerators is complicated by the presence of sulfur oxides (which form acids). Organic compounds also may interfere with or prevent the formation of the cadmium sulfide precipitate or give false positive results because of reaction with iodine. The report presents a…

Hydrogen production through microheterogeneous photocatalysis of hydrogen sulfide cleavage. The thiosulfate cycle

Energy Technology Data Exchange (ETDEWEB)

Borgarello, E; Serpone, N; Graetzel, M; Pelizzetti, E

1985-01-01

Cleavage of hydrogen sulfide into hydrogen and sulfur occurs in alkaline aqueous CdS dispersions under visible light illumination. Small quantities of a noble metal catalyst (RuO/sub 2/) loaded onto 'naked' CdS particles markedly improve the yield of hydrogen formation. The effect of RuO/sub 2/ is ascribed to catalysis of electron transfer to proton. Simultaneous and efficient photogeneration of hydrogen and thiosulfate occurs in CdS dispersions containing both sulfite and bisulfide (or sulfide) ions. Electron transfer from the conduction band of CdS to that of TiO/sub 2/ particles occurs in alkaline suspensions containing these HS/sup -/ ions and has been exploited to improve the performance of a system achieving decomposition of H/sub 2/S by visible light. Equally important is a recent finding that the performance of a system containing 'naked' CdS in combination with RuO/sub 2/-loaded TiO/sub 2/ particles is far better than that of CdS/RuO/sub 2/ alone. Additionally, conduction band electrons produced by bandgap excitation of TiO/sub 2/ particles efficiently reduce thiosulfate to sulfide and sulfite. The valence band process in alklaine TiO/sub 2/ dispersions is thought to involve oxidation of S/sub 2/O/sub 3//sup 2 -/ to tetrathionate, S/sub 4/O/sub 6//sup 2 -/, which quantitatively dismutates into sulfite and thiosulfate. The photodriven disproportionation of thiosulfate into sulfide and sulfate is of great interest in systems that photochemically cleave hydrogen sulfide into hydrogen and sulfur. (author).

Workplace testing of the new single sphere neutron spectrometer based on Dysprosium activation foils (Dy-SSS)

International Nuclear Information System (INIS)

Bedogni, R.; Gómez-Ros, J.M.; Esposito, A.; Gentile, A.; Chiti, M.; Palacios-Pérez, L.; Angelone, M.; Tana, L.

2012-01-01

A photon insensitive passive neutron spectrometer consisting of a single moderating polyethylene sphere with Dysprosium activation foils arranged along three perpendicular axes was designed by CIEMAT and INFN. The device is called Dy-SSS (Dy foil-based Single Sphere Spectrometer). It shows nearly isotropic response in terms of neutron fluence up to 20 MeV. The first prototype, previously calibrated with 14 MeV neutrons, has been recently tested in workplaces having different energy and directional distributions. These are a 2.5 MeV nearly mono-chromatic and mono-directional beam available at the ENEA Frascati Neutron Generator (FNG) and the photo-neutron field produced in a 15 MV Varian CLINAC DHX medical accelerator, located in the Ospedale S. Chiara (Pisa). Both neutron spectra are known through measurements with a Bonner Sphere Spectrometer. In both cases the experimental response of the Dy-SSS agrees with the reference data. Moreover, it is demonstrated that the spectrometric capability of the new device are independent from the directional distribution of the neutron field. This opens the way to a new generation of moderation-based neutron instruments, presenting all advantages of the Bonner sphere spectrometer without the disadvantage of the repeated exposures. This concept is being developed within the NESCOFI@BTF project of INFN (Commissione Scientifica Nazionale 5).

Workplace testing of the new single sphere neutron spectrometer based on Dysprosium activation foils (Dy-SSS)

Science.gov (United States)

Bedogni, R.; Gómez-Ros, J. M.; Esposito, A.; Gentile, A.; Chiti, M.; Palacios-Pérez, L.; Angelone, M.; Tana, L.

2012-08-01

A photon insensitive passive neutron spectrometer consisting of a single moderating polyethylene sphere with Dysprosium activation foils arranged along three perpendicular axes was designed by CIEMAT and INFN. The device is called Dy-SSS (Dy foil-based Single Sphere Spectrometer). It shows nearly isotropic response in terms of neutron fluence up to 20 MeV. The first prototype, previously calibrated with 14 MeV neutrons, has been recently tested in workplaces having different energy and directional distributions. These are a 2.5 MeV nearly mono-chromatic and mono-directional beam available at the ENEA Frascati Neutron Generator (FNG) and the photo-neutron field produced in a 15 MV Varian CLINAC DHX medical accelerator, located in the Ospedale S. Chiara (Pisa). Both neutron spectra are known through measurements with a Bonner Sphere Spectrometer. In both cases the experimental response of the Dy-SSS agrees with the reference data. Moreover, it is demonstrated that the spectrometric capability of the new device are independent from the directional distribution of the neutron field. This opens the way to a new generation of moderation-based neutron instruments, presenting all advantages of the Bonner sphere spectrometer without the disadvantage of the repeated exposures. This concept is being developed within the NESCOFI@BTF project of INFN (Commissione Scientifica Nazionale 5).

Workplace testing of the new single sphere neutron spectrometer based on Dysprosium activation foils (Dy-SSS)

Energy Technology Data Exchange (ETDEWEB)

Bedogni, R., E-mail: roberto.bedogni@lnf.infn.it [INFN-LNF (Frascati National Laboratories), Via E. Fermi n. 40-00044 Frascati (Italy); Gomez-Ros, J.M. [INFN-LNF (Frascati National Laboratories), Via E. Fermi n. 40-00044 Frascati (Italy); CIEMAT, Av. Complutense 40, 28040 Madrid (Spain); Esposito, A.; Gentile, A.; Chiti, M.; Palacios-Perez, L. [INFN-LNF (Frascati National Laboratories), Via E. Fermi n. 40-00044 Frascati (Italy); Angelone, M. [ENEA C.R. Frascati, C.P. 65, 00044 Frascati (Italy); Tana, L. [A.O. Universitaria Pisana-Ospedale S. Chiara, Via Bonanno Pisano, Pisa (Italy)

2012-08-21

A photon insensitive passive neutron spectrometer consisting of a single moderating polyethylene sphere with Dysprosium activation foils arranged along three perpendicular axes was designed by CIEMAT and INFN. The device is called Dy-SSS (Dy foil-based Single Sphere Spectrometer). It shows nearly isotropic response in terms of neutron fluence up to 20 MeV. The first prototype, previously calibrated with 14 MeV neutrons, has been recently tested in workplaces having different energy and directional distributions. These are a 2.5 MeV nearly mono-chromatic and mono-directional beam available at the ENEA Frascati Neutron Generator (FNG) and the photo-neutron field produced in a 15 MV Varian CLINAC DHX medical accelerator, located in the Ospedale S. Chiara (Pisa). Both neutron spectra are known through measurements with a Bonner Sphere Spectrometer. In both cases the experimental response of the Dy-SSS agrees with the reference data. Moreover, it is demonstrated that the spectrometric capability of the new device are independent from the directional distribution of the neutron field. This opens the way to a new generation of moderation-based neutron instruments, presenting all advantages of the Bonner sphere spectrometer without the disadvantage of the repeated exposures. This concept is being developed within the NESCOFI@BTF project of INFN (Commissione Scientifica Nazionale 5).

Nuclear statistics of dysprosium resonance parameters in the energy range 10 - 1000 eV

International Nuclear Information System (INIS)

Shin, S. G.; Kye, Y. U.; Cho, M. H.; Kim, G. N.; Namkung, W.; Lee, M. W.; Kang, Y. R.; Roe, T. I.

2016-01-01

A resonance parameter analysis is often performed in the Resolved Resonance Region (RRR) in order to estimate the average level spacing, distribution of the reduced widths and so on. Neutron Capture experiments on dysprosium isotopes were performed at the electron linear accelerator (LINAC) facility of the Rensselear Polytechnic Institute (RPI) in the neutron energy region from 10 eV to 1 keV. The following nuclear statistics of the resonance parameters will be discussed in this paper. The D 0 for 161 Dy and 163 Dy were judged to be constant up to 120.6 and 163.9 eV, respectively. It was assumed that the D 0 of 162 Dy and 164 Dy is constant up to 1000 eV because they have few resonances. The results were compared with the values from Reference 11 as shown in Figure 1. Statistical distributions of reduced neutron were investigated for the three isotopes in the region from 0 to 1000 eV; 161 Dy, 162 Dy, and 163 Dy, but not for 164 Dy because of a few number of resonances. The reduced neutron widths Γ n 0 were divided by the unweighted average reduced neutron width < Γ n 0 > for each isotope. A cumulative distribution of these unitless ratios is compared with the integral of the Porter-Thomas distribution (χ 2 distribution with one degree of freedom). The results agree reasonably with the Porter Thomas distributions.

NF1, Sp1 and HSF1 are synergistically involved in sulfide-induced sqr activation in echiuran worm Urechis unicinctus

Energy Technology Data Exchange (ETDEWEB)

Liu, Xiaolong; Qin, Zhenkui; Li, Xueyu; Ma, Xiaoyu; Gao, Beibei; Zhang, Zhifeng, E-mail: zzfp107@ouc.edu.cn

2016-06-15

Highlights: • Sulfide activates sqr transcription against respiratory toxicity in Urechis unicinctus. • Sulfide increases expressions and activities of NF1, Sp1 and HSF1 in a time-dependent manner. • NF1 and Sp1 participate in both basal and early sulfide-induced sqr transcription. • HSF1 functions more significantly than NF1 and Sp1 in sulfide-induced sqr transcription. • Transcription factors NF1, Sp1 and HSF1 enhance sqr promoter activity synergistically. - Abstract: Background: Sulfide is a well-known environmental toxic substance. Mitochondrial sulfide oxidation is a main mechanism of sulfide detoxification in organisms, and sulfide: quinone oxidoreductase (SQR) is a key enzyme which is involved in transferring electrons from sulfide to ubiquinone and converting sulfide into thiosulfate. Previous studies have revealed the SQR-mediated mitochondrial sulfide oxidation exists in the echiuran worm Urechis unicinctus, and its sqr mRNA level increased significantly when the worm is exposed to sulfide. In this study, we attempt to reveal the synergistic regulation of transcription factors on sulfide-induced sqr transcription in U. unicinctus. Methods: ChIP and EMSA were used to identify the interactions between sqr proximal promoter (from −391 to +194 bp) and transcription factors NF1 (nuclear factor 1) and Sp1 (specificity protein 1). Site-directed mutation and transfection assays further revealed their binding sites and synergistic roles of HSF1, NF1 and Sp1 in the sqr transcription. When U. unicinctus were exposed to 150 μM sulfide, the expression levels and nuclear contents of NF1 and Sp1 were examined by Western blotting, and the binding contents between NF1 or Sp1 and the sqr promoter were also detected by ChIP. Results: Transcription factors NF1 and Sp1 were confirmed to interact with the sqr proximal promoter, and their binding sites were identified in −75 to −69 bp for NF1 and −210 to −201 bp for Sp1. Transfection assays showed mutation

Insights into Andean metallogenesis from the perspective of Re-Os analyses of sulfides

International Nuclear Information System (INIS)

Mathur, R.; Ruiz, J.R; Munizaga, F.M

2001-01-01

The source of metals and duration of mineralization for ore deposits are basic issues used to describe the metallogenesis of an area. In order to address these fundamental issues in the Andean Cordillera, we chose to analyze Re-Os isotopes in sulfides from twelve porphyry copper ore deposits that are spatially and temporally separated. Re-Os concentrates in sulfide minerals, and can thus provide genetic information on the source of metals and the timing of mineralization. The advantage of using Re-Os isotopes is that genetic and geochronologic information is obtained directly from the sulfide ore mineral, rather than by inferring chemical relationships from possibly unrelated alteration silicates. In this study we use the source of Os in low concentration sulfides as a proxy for the source of base metals. Initial ratios greater than the chondritic mantle (∼0.13) serve as indication of a crustal source for Os and, by inference, other ore forming metals. Molybdenite contains orders of magnitude more Re than the common sulfides and effectively no initial radiogenic 187 Os (Luck and Allegre, 1982). Therefore, it can be used as a high-precision geochronometer (McCandless, 1994; Stein et al. 1997). Re-Os data from low concentration sulfides and chronologic data from high concentration molybdenites highlight important processes within and among these Andean deposits.The low concentration sulfides contain between 5-30 ppt Os and 1- 30 ppb Re. There are two samples of hydrothermal and magmatic magnetite from Escondida that contain slightly more Re and Os than the other sulfides reported. The molybdenites have 187 Os concentrations that range from 5-2000 ppb, and Re concentrations that range from 60-3600 ppm. Mathur et al. (2000) and Mathur (2000) highlighted a strong relationship between the copper tonnage in Andean ore deposits and the Os initial ratio of sulfide minerals. The larger deposits have sulfide minerals with lower initial Os ratios than the smaller, less

Magnetic properties and phase transformations of iron sulfides synthesized under the hydrothermal method

Science.gov (United States)

Li, S. H.; Chen, Y. H.

2016-12-01

The iron sulfide nano-minerals possess advantages of high abundance, low cost, and low toxicity. These advantages make them be competitive in the magnetic, electronic, and photoelectric applications. Mackinawite can be used in soil or water remediations. Greigite is very important for paleomagnetic and geochemical environment studies and the anode materials for lithium ion batteries. Besides, greigite is also utilized for hyperthermia and biomedicine. Pyrrhotite can be applied as geothermometry. Due to the above-mentioned reasons, iron sulfide minerals have specific significances and they must be further investigated, like their phase transformations, magnetic properties, and etc. In this study, the iron sulfide minerals were synthesized by using a hydrothermal method. The ex-situ and in-situ X-ray diffraction (XRD) was used to examine the crystal structure and phase transformation of iron sulfide minerals. The Transmission electron microscopy (TEM) and superconducting quantum interference device (SQUID) were carried out to investigate their morphology and magnetic properties, respectively. The results suggested that the phase transformation sequence was followed the order: mackinawite → greigite → (smythite) → pyrrhotite. Two pure mineral phases of greigite and pyrrhotite were obtained under the hydrothermal conditions. The morphology of the pure greigite is granular aggregates with a particle size of approximately 30 nm and pyrrhotite presented a hexagonal sheet stacking with a particle size of thousands nanometers. The greigite had a ferri-magnetic behavior and pyrrhotite was weak ferro-magnetic. Both of them had a pseudo-single magnetic domain (PSD) based on the Day's plot from SQUID data. The complete phase-transformation pathways and high magnetization of iron sulfide minerals are observed in this study and these kind of iron sulfide minerals are worthy to further study.

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...

Uranium accumulation in modern and ancient Fe-oxide sediments: Examples from the Ashadze-2 hydrothermal sulfide field (Mid-Atlantic Ridge) and Yubileynoe massive sulfide deposit (South Urals, Russia)

Science.gov (United States)

Ayupova, N. R.; Melekestseva, I. Yu.; Maslennikov, V. V.; Tseluyko, A. S.; Blinov, I. A.; Beltenev, V. E.

2018-05-01

Fe-oxyhydroxide sediments (gossans) from the Ashadze-2 hydrothermal sulfide field (Mid-Atlantic Ridge) and hematite-carbonate-quartz rocks (gossanites) from the Yubileynoe Cu-Zn VHMS deposit (South Urals) are characterized by anomalously high U contents (up to 352 ppm and 73 ppm, respectively). In gossans from the Ashadze-2 hydrothermal sulfide field, rare isometric anhedral uraninite grains (up to 2 μm) with outer P- and Ca-rich rims, and numerous smaller (<1 μm) grains, occur in Fe-oxyhydroxides and sepiolite, associated with pyrite, isocubanite, chalcopyrite, galena, atacamite and halite. In gossanites from the Yubileynoe deposit, numerous uraninite particles (<3 μm) are associated with apatite, V-rich Mg-chlorite, micro-nodules of pyrite, Se-bearing galena, hessite and acanthite in a hematite-carbonate-quartz matrix. Small (1-3 μm) round grains of uraninite, which locally coalesce to large grains up to 10 μm in size, are associated with authigenic chalcopyrite. The similar diagenetic processes of U accumulation in modern and ancient Fe-oxyhydroxide sediments were the result of U fixation from seawater during the oxidation of sulfide minerals. Uraninite in gossanites was mainly deposited from diagenetic pore fluids, which circulated in the sulfide-hyaloclast-carbonate sediments.

Extraction of lead from waste CRT funnel glass by generating lead sulfide - An approach for electronic waste management.

Science.gov (United States)

Hu, Biao; Hui, Wenlong

2017-09-01

Waste cathode ray tube (CRT) funnel glass is the key and difficult points in waste electrical and electronic equipment (WEEE) disposal. In this paper, a novel and effective process for the detoxification and reutilization of waste CRT funnel glass was developed by generating lead sulfide precipitate via a high-temperature melting process. The central function in this process was the generation of lead sulfide, which gathered at the bottom of the crucible and was then separated from the slag. Sodium carbonate was used as a flux and reaction agent, and sodium sulfide was used as a precipitating agent. The experimental results revealed that the lead sulfide recovery rate initially increased with an increase in the amount of added sodium carbonate, the amount of sodium sulfide, the temperature, and the holding time and then reached an equilibrium value. The maximum lead sulfide recovery rate was approximately 93%, at the optimum sodium carbonate level, sodium sulfide level, temperature, and holding time of 25%, 8%, 1200°C, and 2h, respectively. The glass slag can be made into sodium and potassium silicate by hydrolysis in an environmental and economical process. Copyright © 2017 Elsevier Ltd. All rights reserved.

Simultaneous Voltammetric/Amperometric Determination of Sulfide and Nitrite in Water at BDD Electrode

Directory of Open Access Journals (Sweden)

Anamaria Baciu

2015-06-01

Full Text Available This work reported new voltammetric/amperometric-based protocols using a commercial boron-doped diamond (BDD electrode for simple and fast simultaneous detection of sulfide and nitrite from water. Square-wave voltammetry operated under the optimized working conditions of 0.01 V step potential, 0.5 V modulation amplitude and 10 Hz frequency allowed achieving the best electroanalytical parameters for the simultaneous detection of nitrite and sulfide. For practical in-field detection applications, the multiple-pulsed amperometry technique was operated under optimized conditions, i.e., −0.5 V/SCE for a duration of 0.3 s as conditioning step, +0.85 V/SCE for a duration of 3 s that assure the sulfide oxidation and +1.25 V/SCE for a duration of 0.3 s, where the nitrite oxidation occurred, which allowed the simultaneously detection of sulfide and nitrite without interference between them. Good accuracy was found for this protocol in comparison with standardized methods for each anion. Also, no interference effect was found for the cation and anion species, which are common in the water matrix.

Bioleaching of a low-grade nickel-copper sulfide by mixture of four thermophiles.

Science.gov (United States)

Li, Shuzhen; Zhong, Hui; Hu, Yuehua; Zhao, Jiancun; He, Zhiguo; Gu, Guohua

2014-02-01

This study investigated thermophilic bioleaching of a low grade nickel-copper sulfide using mixture of four acidophilic thermophiles. Effects of 0.2g/L l-cysteine on the bioleaching process were further evaluated. It aimed at offering new alternatives for enhancing metal recoveries from nickel-copper sulfide. Results showed a recovery of 80.4% nickel and 68.2% copper in 16-day bioleaching without l-cysteine; while 83.7% nickel and 81.4% copper were recovered in the presence of l-cysteine. Moreover, nickel recovery was always higher than copper recovery. l-Cysteine was found contributing to lower pH value, faster microbial growth, higher Oxidation-Reduction Potential (ORP), higher zeta potential and absorbing on the sulfide surfaces through amino, carboxyl and sulfhydryl groups. X-ray Diffraction (XRD) patterns of leached residues showed generation of S, jarosite and ammoniojarosite. Denaturing Gradient Gel Electrophoresis (DGGE) results revealed that l-cysteine could have variant impacts on different microorganisms and changed the microbial community composition dramatically during nickel-copper sulfide bioleaching. Copyright © 2013 Elsevier Ltd. All rights reserved.

Characterizing the effect of carbon steel exposure in sulfide containing solutions to microbially induced corrosion

Energy Technology Data Exchange (ETDEWEB)

Sherar, B.W.A. [Department of Chemistry, University of Western Ontario, London, ON, N6A 5B7 (Canada); Power, I.M. [Department of Earth Sciences, University of Western Ontario, London, ON, N6A 5B7 (Canada); Keech, P.G.; Mitlin, S. [Department of Chemistry, University of Western Ontario, London, ON, N6A 5B7 (Canada); Southam, G. [Department of Earth Sciences, University of Western Ontario, London, ON, N6A 5B7 (Canada); Shoesmith, D.W., E-mail: dwshoesm@uwo.c [Department of Chemistry, University of Western Ontario, London, ON, N6A 5B7 (Canada)

2011-03-15

Research highlights: Compares inorganic sulfide and sulfate reducing bacteria (SRB) on steel corrosion. Mackinawite was the dominant iron sulfide phase. SRBs can form nanowires, presumably grown to acquire energy. - Abstract: This article compares the electrochemical effects induced by inorganic sulfide and sulfate reducing bacteria on the corrosion of carbon steel - a subject of concern for pipelines. Biological microcosms, containing varying concentrations of bioorganic content, were studied to investigate changes to the morphology of biofilms and corrosion product deposits. Raman analysis indicated mackinawite (FeS{sub 1-x}) was the dominant iron sulfide phase grown both abiotically and biotically. A fascinating feature of biological media, void of an organic electron donor, was the formation of putative nanowires that may be grown to acquire energy from carbon steel by promoting the measured cathodic reaction.

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

of sedimentary sulfide in the plant increases, and accumulation of elemental sulfur (S0) inside the plant with δ34S values similar to the sedimentary sulfide suggests that S0 is an important reoxidation product of the sedimentary sulfide. The accumulation of S0 can, however, not account for the increase...... in sulfur in the tissue, and other sulfur containing compounds such as thiols, organic sulfur, and sulfate contribute to the accumulated sulfur pool. Experimental studies with seagrasses exposed to environmental and biological stressors show decreasing δ34S in the tissues along with reduction in growth...

Study for the determination of samarium, europium,terbium, dysprosium and yttrium in gadolinium oxide matrix by means of atomic absorption spectrophotometry using a graphite furnace

International Nuclear Information System (INIS)

Caires, A.C.F.

1985-01-01

A study for determination of samarium, europium, terbium, dysprosium and yttrium in a gadolinium oxide matrix by atomic absorption spectrophotometry using a graphite furnace is presented. The best charrring and atomization conditions were estabilished for each element, the most convenient ressonance lines being selected as well. The study was carried out for the mentioned lanthanides both when pure and when in binary mixtures with gadolinium, besides those where all for them were together with gadolinium. The determination limits for pure lanthanides were found to be between 1.3 and 9.6 ng assuming a 20% relative standard deviation as acceptable. The detection limits were in the range 0.51 and 7.5 ng, assuming as positive any answer higher than twofold the standard deviation. (author) [pt

21 CFR 177.2490 - Polyphenylene sulfide resins.

Science.gov (United States)

2010-04-01

... Components of Articles Intended for Repeated Use § 177.2490 Polyphenylene sulfide resins. Polyphenylene... coatings of articles intended for repeated use in contact with food, in accordance with the following... are available from the Center for Food Safety and Applied Nutrition (HFS-200), Food and Drug...

Reaction between Hydrogen Sulfide and Limestone Calcines

Czech Academy of Sciences Publication Activity Database

Hartman, Miloslav; Svoboda, Karel; Trnka, Otakar; Čermák, Jiří

2002-01-01

Roč. 41, č. 10 (2002), s. 2392-2398 ISSN 0888-5885 R&D Projects: GA AV ČR IAA4072711; GA AV ČR IAA4072801 Keywords : hydrogen sulfide * limestone calcines * desulfurization Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 1.247, year: 2002

Simple micellar electrokinetic chromatography method for the determination of hydrogen sulfide in hen tissues.

Science.gov (United States)

Kubalczyk, Paweł; Borowczyk, Kamila; Chwatko, Grażyna; Głowacki, Rafał

2015-04-01

A new method for the determination of hydrogen sulfide in hen tissues has been developed and validated. For estimation of hydrogen sulfide content, a sample (0.1 g) of hen tissue was treated according to the procedure consisted of some essential steps: simultaneous homogenization of a tissue and derivatization of hydrogen sulfide to its S-quinolinium derivative with 2-chloro-1-methylquinolinium tetrafluoroborate, separation of so-formed derivative by micellar electrokinetic chromatography with sweeping, and detection and quantitation with the use of UV detector set to measure analytical signals at 375 nm. Effective electrophoretic separation was achieved using fused silica capillary (effective length 41.5 cm, 75 μm id) and 0.05 mol/L, pH 8 phosphate buffer with the addition of 0.04 mol/L SDS and 26% ACN. The lower limit of quantification was 0.12 μmol hydrogen sulfide in 1 g of tissue. The calibration curve prepared in tissue homogenate for hydrogen sulfide showed linearity in the range from 0.15 to 2.0 μmol/g, with the coefficient of correlation 0.9978. The relative standard deviation of the points of the calibration curve varied from 8.3 to 3.2% RSD. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The Variation Characteristic of Sulfides and VOSc in a Source Water Reservoir and Its Control Using a Water-Lifting Aerator

Directory of Open Access Journals (Sweden)

Jian-Chao Shi

2016-04-01

Full Text Available Sulfides and volatile organic sulfur compounds (VOSc in water are not only malodorous but also toxic to humans and aquatic organisms. They cause serious deterioration in the ecological environment and pollute drinking water sources. In the present study, a source water reservoir—Zhoucun Reservoir in East China—was selected as the study site. Through a combination of field monitoring and in situ release experiments of sulfides, the characteristics of seasonal variation and distribution of sulfides and VOSc in the reservoir were studied, and the cause of the sulfide pollution was explained. The results show that sulfide pollution was quite severe in August and September 2014 in the Zhoucun Reservoir, with up to 1.59 mg·L−1 of sulfides in the lower layer water. The main source of sulfides is endogenous pollution. VOSc concentration correlates very well with that of sulfides during the summer, with a peak VOSc concentration of 44.37 μg·L−1. An installed water-lifting aeration system was shown to directly oxygenate the lower layer water, as well as mix water from the lower and the upper layers. Finally, the principle and results of controlling sulfides and VOSc in reservoirs using water-lifting aerators are clarified. Information about sulfides and VOSc fluctuation and control gained in this study may be applicable to similar reservoirs, and useful in practical water quality improvement and pollution prevention.

Corrosion resistance of cement brick on an organo-mineral base in a hydrogen sulfide medium

Energy Technology Data Exchange (ETDEWEB)

Potapov, A G; Belousov, G A; Pustovalov, V I; Skorikov, B M

1981-01-01

Results are presented of strength tests of cement brick made of different types of cement as a function of the composition of the mixing liquid and storage conditions. It is established that cement brick made of cement on a cinder base mixed in hydrogen sulfide water possesses the highest corrosive resistance to hydrogen sulfide attack. A marked increase in corrosion resistance is observed in cement brick on an organo-mineral base. Results of industrial tests of organo-mineral grouting mortar in a hydrogen sulfide medium are demonstrated.

Protective Effects of Hydrogen Sulfide in the Ageing Kidney.

Science.gov (United States)

Hou, Cui-Lan; Wang, Ming-Jie; Sun, Chen; Huang, Yong; Jin, Sheng; Mu, Xue-Pan; Chen, Ying; Zhu, Yi-Chun

2016-01-01

Aims . The study aimed to examine whether hydrogen sulfide (H 2 S) generation changed in the kidney of the ageing mouse and its relationship with impaired kidney function. Results . H 2 S levels in the plasma, urine, and kidney decreased significantly in ageing mice. The expression of two known H 2 S-producing enzymes in kidney, cystathionine γ -lyase (CSE) and cystathionine- β -synthase (CBS), decreased significantly during ageing. Chronic H 2 S donor (NaHS, 50  μ mol/kg/day, 10 weeks) treatment could alleviate oxidative stress levels and renal tubular interstitial collagen deposition. These protective effects may relate to transcription factor Nrf2 activation and antioxidant proteins such as HO-1, SIRT1, SOD1, and SOD2 expression upregulation in the ageing kidney after NaHS treatment. Furthermore, the expression of H 2 S-producing enzymes changed with exogenous H 2 S administration and contributed to elevated H 2 S levels in the ageing kidney. Conclusions . Endogenous hydrogen sulfide production in the ageing kidney is insufficient. Exogenous H 2 S can partially rescue ageing-related kidney dysfunction by reducing oxidative stress, decreasing collagen deposition, and enhancing Nrf2 nuclear translocation. Recovery of endogenous hydrogen sulfide production may also contribute to the beneficial effects of NaHS treatment.

Pertechnetate immobilization in aqueous media with hydrogen sulfide under anaerobic and aerobic environments

International Nuclear Information System (INIS)

Liu, Y.; Jurisson, S.; Terry, J.

2007-01-01

The basic chemistry for the immobilization of pertechnetate (TcO 4 - ) by hydrogen sulfide was investigated in aqueous solution under both aerobic and anaerobic environments. Pertechnetate immobilization was acid dependent, with accelerated rates and increased immobilization yields as the acid concentration increased. Oxygen had no effect under acidic conditions. Under anaerobic alkaline conditions, the pH, and therefore the speciation of sulfide, was the determining factor on the immobilization of pertechnetate. Only 53% of the TcO 4 - was immobilized at pH 8, while the yield increased to 83% at pH 9 as HS - became the dominant sulfide species. The immobilization yield then decreased to 73% at pH 13. No reaction was observed between TcO 4 - and sulfide under aerobic alkaline conditions, indicating that oxygen suppressed this reaction. Pertechnetate immobilization was found to be first order with respect to both sulfide and pertechnetate in acidic solutions, and in alkaline solution under anaerobic conditions. The results of stoichiometry studies and product analysis under alkaline anaerobic environments indicated that Tc 2 S 7 was obtained at pH 9. EXAFS (extended X-ray absorption fine structure) and XANES (X-ray absorption near edge structure) studies suggested that the samples obtained from acidic, aerobic solution and alkaline anaerobic solution were both Tc 2 S 7 . The stability of Tc 2 S 7 is affected by O 2 with accelerated dissolution at high pH. (orig.)

An eco-friendly oxidation of sulfide compounds

Indian Academy of Sciences (India)

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.

Experimental and theoretical approach on the optical properties of zinc borotellurite glass doped with dysprosium oxide

Science.gov (United States)

Halimah, M. K.; Ami Hazlin, M. N.; Muhammad, F. D.

2018-04-01

A series of glass samples with chemical formula {[(TeO2)0.7(B2O3)0.3]0.7(ZnO)0.3}1 - x(Dy2O3)x where x = 0.01, 0.02, 0.03, 0.04 and 0.05 M fraction were synthesized through conventional melt-quenching method. The most common way to fabricate a glass material is by fusion of two or more component oxides followed by their quenching. This technique is known as melt-quenching technique. Kaur et al. (2016) [1] highlighted that the melt-quenching method able to enhance the mechanical properties like hardness and flexural strength of the material. The nature of the glass systems is proven to be amorphous based on the XRD pattern. The FTIR spectra of the glass systems confirm the existence of five bands which are assigned for the BO4, BO3, TeO4 and TeO3 vibrational groups. The density of the glass systems is increased with the addition of Dy2O3 while the molar volume is found to be inversely proportional to the density of the proposed glass. The optical properties of the glasses are determined through the absorption spectra obtained from the UV-VIS spectrophotometer. From the absorption spectra, the indirect and direct optical band gaps and the Urbach energy are found to be inversely proportional to each other. As the molar fraction of the Dy2O3 increased, the optical band gaps are observed to increase as opposed to the Urbach energy. For this glass system, the values of refractive index, electronic polarizability, oxide ion polarizability and the optical basicity are found to decrease as the addition of the dysprosium oxide is increased. From the emission spectra, two intense blue and yellow emission bands are observed, which correspond to the 4F9/2 → 6H15/2 and 4F9/2 → 6H13/2 transitions of Dy3 + ions respectively. The CIE chromaticity coordinates of the zinc borotellurite glass systems are found to be located in the white light region. Generation of white light The generation of the white light can be achieved by using two emission bands which comprise of the yellow

Trace elements in tourmalines from massive sulfide deposits and tourmalinites: Geochemical controls and exploration applications

Science.gov (United States)

Griffin, W.L.; Slack, J.F.; Ramsden, A.R.; Win, T.T.; Ryan, C.G.

1996-01-01

Trace element contents of tourmalines from massive sulfide deposits and tourmalinites have been determined in situ by proton microprobe; >390 analyses were acquired from 32 polished thin sections. Concentrations of trace elements in the tourmalines vary widely, from Sr, Ba, and Ca). Base metal proportions in the tourmalines show systematic patterns on ternary Cu-Pb-Zn diagrams that correlate well with the major commodity metals in the associated massive sulfide deposits. For example, data for tourmalines from Cu-Zn deposits (e.g., Ming mine, Newfoundland) fall mainly on the Cu-Zn join, whereas those from Pb-Zn deposits (e.g., Broken Hill, Australia) plot on the Pb-Zn join; no data fall on the Cu-Pb join, consistent with the lack of this metal association in massive sulfide deposits. The systematic relationship between base metal proportions in the tourmalines and the metallogeny of the host massive sulfide deposits indicates that the analyzed tourmalines retain a strong chemical signature of their original hydrothermal formation, in spite of variable metamorphic recrystallization. Such trace element patterns in massive sulfide tourmalines may be useful in mineral exploration, specifically for the evaluation of tourmaline concentrations in rocks, soils, and stream sediments.

Motility of Marichromatium gracile in Response to Light, Oxygen, and Sulfide

DEFF Research Database (Denmark)

Thar, Roland Matthias; Kühl, Michael

2001-01-01

The motility of the purple sulfur bacterium Marichromatium gracile was investigated under different light regimes in a gradient capillary setup with opposing oxygen and sulfide gradients. The gradients were quantified with microsensors, while the behavior of swimming cells was studied by video...... microscopy in combination with a computerized cell tracking system. M. gracile exhibited photokinesis, photophobic responses, and phobic responses toward oxygen and sulfide. The observed migration patterns could be explained solely by the various phobic responses. In the dark, M. gracile formed an ~500-µm...

Impact of Sulfide on Nitrate Conversion in Eutrophic Nitrate-Rich Marine Sludge

DEFF Research Database (Denmark)

Schwermer, Carsten U.; Krieger, Bärbel; Lavik, Gaute

2006-01-01

IMPACT OF SULFIDE ON NITRATE CONVERSION IN EUTROPHIC NITRATE-RICH MARINE SLUDGE C.U. Schwermer 1, B.U. Krieger 2, G. Lavik 1, A. Schramm 3, J. van Rijn 4, D. de Beer 1, D. Minz 5, E. Cytryn 4, M. Kuypers 1, A. Gieseke 1 1 Max Planck Institute for Marine Microbiology, Bremen, Germany; 2 Dept...... nitrate conversion from denitrification to dissimilatory nitrate-reduction to ammonium (DNRA). In situ microsensor profiling in stagnant sludge revealed the typical stratification of nitrate reduction on top of sulfate reduction. Increasing the bulk nitrate concentration lead to a downward shift....... Our results show that the presence of sulfide generally decreased growth rates but increased N2O production. We conclude that sulfide plays a key role in causing incomplete denitrification, presumably by inhibiting the N2O reductase, and enhancing DNRA compared to denitrification.  ...

Sulfide geochronlogy along the Southwest Indian Ridge

Science.gov (United States)

Yang, W.; Tao, C.; Li, H.; Liang, J.; Liao, S.

2017-12-01

Dragon Flag and Duanqiao hydrothermal field is located between the Indomed and Gallieni fracture zones in the ultraslow-spreading Southwest Indian Ridge (SWIR). Ten subsamples from active and inactive vents of Dragon Flag hydrothermal field and twenty-eight subsamples from Duanqiao hydrothermal field were dated using the 230Th/238U method. Four main episodes of hydrothermal activity of Duanqiao were determined according to the restricted results: 68.9-84.3, 43.9-48.4, 25.3-34.8, and 0.7-17.3 kyrs. Hydrothermal activity of Duanqiao probably started about 84.3 (±0.5) kyrs ago and ceased about 0.737 (±0.023) kyrs ago. And sulfide samples from the nearby Dragon Flag filed at the same time and the results show that the ages of most sulfides from Dragon Flag field range from 1.496(±0.176) to 5.416 (±0.116) kyrs with the oldest age estimated at 15.997 (±0.155) kyrs Münch et al. (2001) reconstructed the evolution history of Mt. Jourdanne hydrothermal field. The age dating results indicate activity in two episodes, at 70-40 and 27-13 kyrs. The hydrothermal activity in Dragon Flag field is much more recent than that of Duanqiao or Mt. Jourdanne fields. The massive sulfides are younger than the sulfides from other hydrothermal fields such as Rainbow, Sonne and Ashadze-2. All these results suggest that hydrothermal activity of Dragon Flag field is much more recent than that of Duanqiao or Mt. Jourdanne fields. Mt. Jourdanne is situated on an axial volcanic ridge which has both volcanic and tectonic activity. This is necessary to develop the heat source and pathways for the fluid convection, which enables the hydrothermal circulation. Hydrothermal activity in Dragon Flag Field is located next to the detachment fault termination. The detachment fault system provides a pathway for hydrothermal convection. Such style of heat source can contribute to continuous hydrothermal activity for over 1000 years. Duanqiao field is located near the central volcano and there is a hot

Instrument for Airborne Measurement of Carbonyl Sulfide, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Southwest Sciences proposes to develop small, low power instrumentation for the real-time direct measurement of carbonyl sulfide (OCS) in the atmosphere, especially...

Occupational exposure to hydrogen sulfide: management of hydrogen sulfide exposure victims (Preprint No. SA-5)

International Nuclear Information System (INIS)

Srivastava, P.P.

1989-04-01

National Institute of Occupational Safety and Health, U.S.A. has listed 73 industries with potential exposure to hydrogen sulphide. Though the toxicity of hydrogen sulfide is known to mankind since the beginning of seventeenth century the exact mode of its toxicity and effective therapeutic regimen remains unclear as yet. This paper presents current thoughts on the toxicity of this substance and a discussion on the role of various antidotes used in H 2 S poisoning. (autho r)

Disguised as a Sulfate Reducer: Growth of the Deltaproteobacterium Desulfurivibrio alkaliphilus by Sulfide Oxidation with Nitrate

Directory of Open Access Journals (Sweden)

Casper Thorup

2017-07-01

Full Text Available This study demonstrates that the deltaproteobacterium Desulfurivibrio alkaliphilus can grow chemolithotrophically by coupling sulfide oxidation to the dissimilatory reduction of nitrate and nitrite to ammonium. Key genes of known sulfide oxidation pathways are absent from the genome of D. alkaliphilus. Instead, the genome contains all of the genes necessary for sulfate reduction, including a gene for a reductive-type dissimilatory bisulfite reductase (DSR. Despite this, growth by sulfate reduction was not observed. Transcriptomic analysis revealed a very high expression level of sulfate-reduction genes during growth by sulfide oxidation, while inhibition experiments with molybdate pointed to elemental sulfur/polysulfides as intermediates. Consequently, we propose that D. alkaliphilus initially oxidizes sulfide to elemental sulfur, which is then either disproportionated, or oxidized by a reversal of the sulfate reduction pathway. This is the first study providing evidence that a reductive-type DSR is involved in a sulfide oxidation pathway. Transcriptome sequencing further suggests that nitrate reduction to ammonium is performed by a novel type of periplasmic nitrate reductase and an unusual membrane-anchored nitrite reductase.

Element enrichment and U-series isotopic characteristics of the hydrothermal sulfides at Jade site in the Okinawa Trough

Institute of Scientific and Technical Information of China (English)

无

2009-01-01

The geochemical and U-series isotopic characteristics of hydrothermal sulfide samples from the Jade site (127°04.5′E, 27°15′N, water depth 1300-1450 m) at Jade site in the Okinawa Trough were analyzed. In the hydrothermal sulfide samples bearing sulfate (samples HOK1 and HOK2), the LREEs are relatively enriched. All the hydrothermal sulfide samples except HOK1 belong to Zn-rich hydrothermal sulfide. In comparison with Zn-rich hydrothermal sulfides from other fields, the contents of Zn, Pb, Ag, Cd, Au and Hg are higher, the contents of Fe, Al, Cr, Co, Ni, Sr, Te, Cs, Ti and U lower, and the 210Pb radioactivity ratios and 210Pb/Pb ratios very low. In the hydrothermal sulfide mainly composed of sphalerite, the correlations between rare elements Hf and U, and Hf and Mn as well as that between dispersive elements Ga and Zn, are strongly positive; also the contents of Au and Ag are related to Fe-sulfide, because the low temperature promotes enrichment of Au and Ag. Meanwhile, the positive correlations between Fe and Bi and between Zn and Cd are not affected by the change of mineral assemblage. Based on the 210Pb/Pb ratios of hydrothermal sulfide samples (3.99×10-5-5.42×10?5), their U isotopic composition (238U content 1.15-2.53 ppm, 238U activity 1.07-1.87 dpm/g, 234U activity 1.15-2.09 dpm/g and 234U/238U ratio 1.07-1.14) and their 232Th and 230Th contents are at base level, and the chronological age of hydrothermal sulfide at Jade site in the Okinawa Trough is between 200 and 2000 yr.

Geochemical features of sulfides from the Deyin-1 hydrothermal field at the southern Mid-Atlantic Ridge near 15°S

Science.gov (United States)

Wang, Shujie; Li, Huaiming; Zhai, Shikui; Yu, Zenghui; Cai, Zongwei

2017-12-01

In this study, geochemical compositions of elements in sulfide samples collected from the Deyin-1 hydrothermal field near the 15°S southern Mid-Atlantic Ridge (SMAR) were analyzed by the X-ray fluorescence spectrometry (XRF) and inductively coupled plasma mass spectrometry (ICP-MS) to examine the enrichment regulations of ore-forming elements and hydrothermal mineralization. These sulfide precipitates can be classified macroscopically into three types: Fe-rich sulfide, Fe-Cu-rich sulfide and Fe-Zn-rich sulfide, and are characterized by the enrichment of base metal elements along with a sequence of Fe>Zn>Cu. Compared with sulfides from other hydrothermal fields on MAR, Zn concentrations of sulfides in the research area are significantly high, while Cu concentrations are relatively low. For all major, trace or rare-earth elements (REE), their concentrations and related characteristic parameters exhibit significant variations (up to one or two orders of magnitude), which indicates the sulfides from different hydrothermal vents or even a same station were formed at different stages of hydrothermal mineralization, and suggests the variations of chemical compositions of the hydrothermal fluid with respect to time. The hydrothermal temperatures of sulfides precipitation decreased gradually from station TVG10 (st.TVG10) to st.TVG12, and to st.TVG11, indicating that the precipitation of hydrothermal sulfides is subjected to conditions changed from high temperature to low temperature, and that the hydrothermal activity of study area was at the late stage of a general trend of evolution from strong to weak. The abnormally low concentrations of REE in sulfides and their similar chondrite-normalized REE patterns show that REEs in all sulfides were derived from a same source, but underwent different processes of migration or enrichment, or sulfides were formed at different stages of hydrothermal mineralization. The sulfides collected from the active hydrothermal vent were

The behavior of molybdenum and its isotopes across the chemocline and in the sediments of sulfidic Lake Cadagno, Switzerland

DEFF Research Database (Denmark)

Dahl, Tais W.; Anbar, Ariel D.; Gordon, Gwyneth W.

2010-01-01

scavenging of Mo when buried into sulfidic sediments. This paper contains the first complete suite of Mo isotope fractionation observations in a sulfidic water column and sediment system, the meromictic Lake Cadagno, Switzerland, a small alpine lake with a pronounced oxygen-sulfide transition reaching up...

Leaching of strontium sulfide from produced clinker in conversion furnace

International Nuclear Information System (INIS)

Ghorbanian, S. A.; Salehpour, A. R.; Radpour, S. R.

2009-01-01

Iran is rich in mineral resources one of which is mineral Celestine. Basing on current estimations, the capacity of mineral Celestine is over two million tons, 75-95% of which is strontium sulfate. However; in industries such as Color cathode Ray Tubes, pyrochemical processes, ceramics, paint production, zinc purification processes; strontium sulfate is not a direct feed, rather it is largely consumed in the form of strontium carbonate. Two conventional methods are used to produce strontium carbonate from the sulfate; that is direct reaction and black ash methods. Strontium sulfide, as an intermediate component has a key role in black ash process including strontium sulfate reduction by coke, hence producing and leaching the strontium sulfide by hot water. Finally the reaction of strontium sulfate with sodium carbonate lead to strontium carbonate. In this paper, a system was designed to analyze and optimize the process parameters of strontium sulfide production which is less expensive and available solvent in water. Fundamentally, when strontium sulfide becomes in contact with strontium sulfate; Sr(SH) 2 , and Sr(OH) 2 , are produced. The solubility of strontium sulfide depends on water temperature and the maximum solubility achieved at 90 d egree C . The results showed that in the experimental scale, at water to SrS ratio of 6; they sediment for 45 minutes at 95 d egree C in five operational stages; the separation of 95 and 97.1 percent of imported SrS is possible in effluent of fourth and fifth stages, respectively. Thus; four leaching stages could be recommended for pilot scale plants. Also, the results show that at water to SrS ratio of 8, 40 minutes sedimentation at 85-95 d egree C in one operational stage, the separation of 95 percent separation of inputted SrS, is possible. Solvent leaching process is continued till no smell of sulfur components is felt. It could be used as a key role to determine the number of leaching stages in experiments. Finally, the

Production of 99mTc-anatomy sulfide colloid for lymphoscintigraphy

International Nuclear Information System (INIS)

Shabani, G. A.; Hamzeh, H.; Najafi, R.

2002-01-01

The lymphatic system provides one of the chief paths for the spread (metastasis) of cancer from one part of body to another. Hodgkin's diseases, lymphocytic leukemia, various metastatic diseases and many lymph ode disorders can be assessed by lymphoscintigraphy. Radionuclide lymphoscintigraphy has been used for many years to define the lymphatic drainage of melanoma. The most common radiopharmaceuticals used for lymphoscintigraphy are 99 mTc-Sc, 99 mTc-antimony sulfide colloid has been chosen between other colloids. For antimony sulfide colloid preparation, hydrogen sulfide gas was passed through D.E. until saturation. Antimony potassium tartrate is then added to the solution to form Sb 2 S 3 ol lide. The colloid was stabilized with P.V.P. Excess H 2 S was removed by bubbling with nitrogen. The preparation was then filtered through a 0.22 μm membrane filter and aliquots containing 1.017 mg Sb 2 S 3 were dispensed into the reaction vials. Labeling was accomplished by adding 99 mTcO 4 and HCl to the vial and then heating it at 100 deg C in boiling water bath for 10 min. The P H was adjust by adding a phosphate buffer. The radiochemical purity of 99 mTc-antimony disulfide colloid by I TLC-S G/normal saline was more than 95 percent. The amount of Sb in reaction vial was 0. 729 mg. The study demonstrated that our formulation of antimony-sulfide which has 0.0486 mg (Sb) in 0.2 ml of 99 mTc-Sb 2 S 3 colloid per patient (total volume after labeling with 99 mTc is 3 ml)

Red soil as a regenerable sorbent for high temperature removal of hydrogen sulfide from coal gas

International Nuclear Information System (INIS)

Ko, T.-H.; Chu Hsin; Lin, H.-P.; Peng, C.-Y.

2006-01-01

In this study, hydrogen sulfide (H 2 S) was removed from coal gas by red soil under high temperature in a fixed-bed reactor. Red soil powders were collected from the northern, center and southern of Taiwan. They were characterized by XRPD, porosity analysis and DCB chemical analysis. Results show that the greater sulfur content of LP red soils is attributed to the higher free iron oxides and suitable sulfidation temperature is around 773 K. High temperature has a negative effect for use red soil as a desulfurization sorbent due to thermodynamic limitation in a reduction atmosphere. During 10 cycles of regeneration, after the first cycle the red soil remained stable with a breakthrough time between 31 and 36 min. Hydrogen adversely affects sulfidation reaction, whereas CO exhibits a positive effect due to a water-shift reaction. COS was formed during the sulfidation stage and this was attributed to the reaction of H 2 S and CO. Results of XRPD indicated that, hematite is the dominant active species in fresh red soil and iron sulfide (FeS) is a product of the reaction between hematite and hydrogen sulfide in red soils. The spinel phase FeAl 2 O 4 was found during regeneration, moreover, the amount of free iron oxides decreased after regeneration indicating the some of the free iron oxide formed a spinel phase, further reducting the overall desulfurization efficiency

New sulfide catalysts for the hydroliquefaction of coal

NARCIS (Netherlands)

Vissers, J.P.R.; Oers, van E.M.; Beer, de V.H.J.; Prins, R.

1987-01-01

Possibilities for the preparation of new metal sulfide catalyst systems based on carbon carriers having favourable textural and surface properties have been explored, and attention has been given to the characterization (structure) and evaluation (hydrosulfurization activity) of these catalysts. Two

A highly stable and sensitive chemically modified screen-printed electrode for sulfide analysis

Energy Technology Data Exchange (ETDEWEB)

Tsai, D.-M. [Department of Chemistry, National Chung Hsing University, 250 Kuo-Kuang Road, Taichung 40217, Taiwan (China); Kumar, Annamalai Senthil [Department of Chemistry, National Chung Hsing University, 250 Kuo-Kuang Road, Taichung 40217, Taiwan (China); Zen, J.-M. [Department of Chemistry, National Chung Hsing University, 250 Kuo-Kuang Road, Taichung 40217, Taiwan (China)]. E-mail: jmzen@dragon.nchu.edu.tw

2006-01-18

We report here a highly stable and sensitive chemically modified screen-printed carbon electrode (CMSPE) for sulfide analysis. The CMSPE was prepared by first ion-exchanging ferricyanide into a Tosflex anion-exchange polymer and then sealing with a tetraethyl orthosilicate sol-gel layer. The sol-gel overlayer coating was crucial to stabilize the electron mediator (i.e., Fe(China){sub 6} {sup 3-}) from leaching. The strong interaction between the oxy-hydroxy functional group of sol-gel and the hydrophilic sites of Tosflex makes the composite highly rigid to trap the ferricyanide mediator. An obvious electrocatalytic sulfide oxidation current signal at {approx}0.20 V versus Ag/AgCl in pH 7 phosphate buffer solution was observed at the CMSPE. A linear calibration plot over a wide range of 0.1 {mu}M to 1 mM with a slope of 5.6 nA/{mu}M was obtained by flow injection analysis. The detection limit (S/N = 3) was 8.9 nM (i.e., 25.6 ppt). Practical utility of the system was applied to the determination of sulfide trapped from cigarette smoke and sulfide content in hot spring water.

Fabrication and applications of copper sulfide (CuS) nanostructures

Energy Technology Data Exchange (ETDEWEB)

Shamraiz, Umair, E-mail: umairshamraiz@gmail.com; Hussain, Raja Azadar, E-mail: hussainazadar@gamil.com; Badshah, Amin, E-mail: aminbadshah@yahoo.com

2016-06-15

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). - Highlights: • This review article presents the synthesis and applications of copper sulfide. • CuS has been used over the years for different applications in nanoscience. • Different synthetic protocols are followed for their preparation which help in the possible modifications in the morphology of CuS.

Influence of mechanical activation on the Moessbauer spectra of the sulfides

International Nuclear Information System (INIS)

Lipka, J.; Miglierini, M.; Sitek, J.; Balaz, P.; Tkacova, K.

1993-01-01

Moessbauer spectroscopy, X-ray photoelectron spectroscopy, infrared spectroscopy, electron paramagnetic resonance and X-ray diffraction were used to identify changes of surface, structure and spectroscopic properties of sulfide minerals produced by mechanical activation. In the present study we report the results of chalcopyrite (CuFeS 2 ), pyrite (FeS 2 ), cinnabar (HgS), bornite (Cu 5 FeS 4 ) and zinc sulfide (ZnS). The influence of energy input to the mill and the nature of grinding environment have been investigated upon the Fe contamination of the materials. (orig.)

Influence of mechanical activation on the Moessbauer spectra of the sulfides

Energy Technology Data Exchange (ETDEWEB)

Lipka, J.; Miglierini, M.; Sitek, J. (Dept. of Nuclear Physics and Technology, Slovak Technical Univ., Bratislava, Slovak Republic (Czechoslovakia)); Balaz, P.; Tkacova, K. (Mining Inst. of the Slovak Academy of Sciences, Kosice, Slovak Republic (Czechoslovakia))

1993-04-01

Moessbauer spectroscopy, X-ray photoelectron spectroscopy, infrared spectroscopy, electron paramagnetic resonance and X-ray diffraction were used to identify changes of surface, structure and spectroscopic properties of sulfide minerals produced by mechanical activation. In the present study we report the results of chalcopyrite (CuFeS[sub 2]), pyrite (FeS[sub 2]), cinnabar (HgS), bornite (Cu[sub 5]FeS[sub 4]) and zinc sulfide (ZnS). The influence of energy input to the mill and the nature of grinding environment have been investigated upon the Fe contamination of the materials. (orig.).

Chemical and colloidal aspects of collectorless flotation behavior of sulfide and non-sulfide minerals.

Science.gov (United States)

Aghazadeh, Sajjad; Mousavinezhad, Seyed Kamal; Gharabaghi, Mahdi

2015-11-01

Flotation has been widely used for separation of valuable minerals from gangues based on their surface characterizations and differences in hydrophobicity on mineral surfaces. As hydrophobicity of minerals widely differs from each other, their separation by flotation will become easier. Collectors are chemical materials which are supposed to make selectively valuable minerals hydrophobic. In addition, there are some minerals which based on their surface and structural features are intrinsically hydrophobic. However, their hydrophobicities are not strong enough to be floatable in the flotation cell without collectors such as sulfide minerals, coal, stibnite, and so forth. To float these minerals in a flotation cell, their hydrophobicity should be increased in specific conditions. Various parameters including pH, Eh, size distribution, mill types, mineral types, ore characterization, and type of reaction in flotation cells affect the hydrophobicity of minerals. Surface analysis results show that when sulfide minerals experience specific flotation conditions, the reactions on the surface of these minerals increase the amount of sulfur on the surface. These phenomenons improve the hydrophobicity of these minerals due to strong hydrophobic feature of sulfurs. Collectorless flotation reduces chemical material consumption amount, increases flotation selectivity (grade increases), and affects the equipment quantities; however, it can also have negative effects. Some minerals with poor surface floatability can be increased by adding some ions to the flotation system. Depressing undesirable minerals in flotation is another application of collectorless flotation.

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.

Determination of the products from the oxidation of aqueous hydrogen sulfide by sulfur K-edge XANES spectroscopy

International Nuclear Information System (INIS)

Vairavamurthy, A.; Manowitz, B.; Jeon, Yongseog; Zhou, Weiqing.

1993-01-01

The application of synchrotron radiation based XANES spectroscopy is described for determining the products formed from oxidation of aqueous sulfide.This technique allows simultaneous characterization of all the different forms of sulfur both qualitatively and quantitatively. Thus, it is superior to other commonly used techniques, such as chromatography, which are usually targeted at specific compounds. Since the use of XANES-based technique is relatively new in geochemistry, we present here an overview of the principles of the technique as well as the approach used for quantitative analysis. We studied the sulfide oxidation under conditions of high sulfide to oxygen ratio using 0.1 M sulfide solutions and the catalytic effects of sea sand, Fe 2+ , and Ni 2+ , were also examined. Significant results obtained from this study are presented to illustrate the value of the XANES technique for the determination of the products formed from the oxidation of sulfide at high concentrations

Biotechnological reduction of sulfide in an industrial primary wastewater treatment system: A sustainable and successful case study

Energy Technology Data Exchange (ETDEWEB)

Rajamani, S. [Central Leather Research Institute, Madras (India)

1996-12-31

The leather industry is an important export-oriented industry in India, with more than 3,000 tanneries located in different clusters. Sodium sulfide, a toxic chemical, is used in large quantities to remove hair and excess flesh from hides and skins. Most of the sodium sulfide used in the process is discharged as waste in the effluent, which causes serious environmental problems. Reduction of sulfide in the effluent is generally achieved by means of chemicals in the pretreatment system, which involves aerobic mixing using large amounts of chemicals and high energy, and generating large volumes of sludge. A simple biotechnological system that uses the residual biosludge from the secondary settling tank was developed, and the commercial-scale application established that more than 90% of the sulfide could be reduced in the primary treatment system. In addition to the reduction of sulfide, foul smells, BOD and COD are reduced to a considerable level. 3 refs., 2 figs., 1 tab.

Effect of Ni on the characteristics and hydrogenation activity of sulfide Mo/γ-Al2O3

International Nuclear Information System (INIS)

Schachtl, E.; Wuttke, E.; Gutierrez, O.Y.; Lercher, J.A.

2012-01-01

The hydrogenation of phenanthrene was explored on sulfide Mo/γ-Al 2 O 3 catalysts promoted with increasing concentrations of Ni. The characterization of the materials was done by N 2 -physisorption, X-ray diffraction, transmission electron microscopy, temperature programmed sulfidation and NO adsorption experiments. Increasing loading of Ni improves the dispersion of MoS 2 species; however, at Ni/(Mo+Ni) molar ratio higher than 0.5, segregation of Ni-sulfides is observed. The presence of Ni also facilitates the sulfidation of oxidic catalyst precursors by lowering the reduction temperature of Mo species. In the sulfide catalysts, Ni changes the structure of MoS 2 leading to shorter slabs with higher stacking degree than on Mo/γ-Al 2 O 3 , and increases the concentration of coordinatively unsaturated sites. The kinetic results (increased hydrogenation rate and changed reaction network in the presence of Ni) suggest that a highly active kind of active site is created by Ni promotion. (orig.)

Hydrogen sulfide synthesis enzymes reduced in lower esophageal sphincter of patients with achalasia.

Science.gov (United States)

Zhang, L; Zhao, W; Zheng, Z; Wang, T; Zhao, C; Zhou, G; Jin, H; Wang, B

2016-10-01

The etiology of achalasia remains largely unknown. Considerable evidence reveals that the lower esophageal sphincter dysfunction is due to the lack of inhibitory neurotransmitter, secondary to esophageal neuronal inflammation or loss. Recent studies suggest hydrogen sulfide may act as an inhibitory transmitter in gastrointestinal tract, but study about hydrogen sulfide in human esophagus still lack. The aim of the study was to investigate if hydrogen sulfide synthesis enzymes could be detected in human esophagus and if the synthesis of the endogenous hydrogen sulfide could be affected in achalasia patients. Tissue samples in cardia, lower esophageal sphincter, 2 cm and 4 cm above lower esophageal sphincter were obtained from achalasia patients undergoing peroral endoscopic myotomy. Control tissues in lower esophageal sphincter were obtained from esophageal carcinoma patients. Expression of cystathionine-β-synthase and cystathionine-γ-lyase in lower esophageal sphincter of achalasia patients and control were detected by immunohistochemical staining. In addition, expression of cystathionine-β-synthase and cystathionine-γ-lyase were compared among different parts of esophagus in achalasia patients. Compared with control, the expression of cystathionine-β-synthase and cystathionine-γ-lyase in lower esophageal sphincter of achalasia patients was significantly reduced (χ 2 = 11.429, P = 0.010). The expression of cystathionine-β-synthase and cystathionine-γ-lyase were lower in lower esophageal sphincter than that in 2 cm and 4 cm above lower esophageal sphincter, respectively (all P achalasia, which implicates the involvement of the two hydrogen sulfide synthesis enzymes in the pathophysiology of achalasia. © 2015 International Society for Diseases of the Esophagus.

Hydrogen sulfide ameliorated L-NAME-induced hypertensive heart disease by the Akt/eNOS/NO pathway.

Science.gov (United States)

Jin, Sheng; Teng, Xu; Xiao, Lin; Xue, Hongmei; Guo, Qi; Duan, Xiaocui; Chen, Yuhong; Wu, Yuming

2017-12-01

Reductions in hydrogen sulfide (H 2 S) production have been implicated in the pathogenesis of hypertension; however, no studies have examined the functional role of hydrogen sulfide in hypertensive heart disease. We hypothesized that the endogenous production of hydrogen sulfide would be reduced and exogenous hydrogen sulfide would ameliorate cardiac dysfunction in N ω -nitro- L-arginine methyl ester ( L-NAME)-induced hypertensive rats. Therefore, this study investigated the cardioprotective effects of hydrogen sulfide on L-NAME-induced hypertensive heart disease and explored potential mechanisms. The rats were randomly divided into five groups: Control, Control + sodium hydrosulfide (NaHS), L-NAME, L-NAME + NaHS, and L-NAME + NaHS + glibenclamide (Gli) groups. Systolic blood pressure was monitored each week. In Langendorff-isolated rat heart, cardiac function represented by ±LV dP/dt max and left ventricular developing pressure was recorded after five weeks of treatment. Hematoxylin and Eosin and Masson's trichrome staining and myocardium ultrastructure under transmission electron microscopy were used to evaluate cardiac remodeling. The plasma nitric oxide and hydrogen sulfide concentrations, as well as nitric oxide synthases and cystathionine-γ-lyase activity in left ventricle tissue were determined. The protein expression of p-Akt, Akt, p-eNOS, and eNOS in left ventricle tissue was analyzed using Western blot. After five weeks of L-NAME treatment, there was a time-dependent hypertension, cardiac remodeling, and dysfunction accompanied by a decrease in eNOS phosphorylation, nitric oxide synthase activity, and nitric oxide concentration. Meanwhile, cystathionine-γ-lyase activity and hydrogen sulfide concentration were also decreased. NaHS treatment significantly increased plasma hydrogen sulfide concentration and subsequently promoted the Akt/eNOS/NO pathway which inhibited the development of hypertension and attenuated cardiac remodeling and

Preliminary X-ray crystallographic analysis of sulfide:quinone oxidoreductase from Acidithiobacillus ferrooxidans

International Nuclear Information System (INIS)

Zhang, Yanfei; Cherney, Maia M.; Solomonson, Matthew; Liu, Jianshe; James, Michael N. G.; Weiner, Joel H.

2009-01-01

The sulfide:quinone oxidoreductase from A. ferrooxidans ATCC 23270 was overexpressed in E. coli and purified. Crystallization and preliminarily X-ray crystallographic analysis were performed for the recombinant enzyme. The gene product of open reading frame AFE-1293 from Acidithiobacillus ferrooxidans ATCC 23270 is annotated as encoding a sulfide:quinone oxidoreductase, an enzyme that catalyses electron transfer from sulfide to quinone. Following overexpression in Escherichia coli, the enzyme was purified and crystallized using the hanging-drop vapour-diffusion method. The native crystals belonged to the tetragonal space group P4 2 2 1 2, with unit-cell parameters a = b = 131.7, c = 208.8 Å, and diffracted to 2.3 Å resolution. Preliminary crystallographic analysis indicated the presence of a dimer in the asymmetric unit, with an extreme value of the Matthews coefficient (V M ) of 4.53 Å 3 Da −1 and a solvent content of 72.9%

Study of upscaling possibilities for antimony sulfide solid state sensitized solar cells

Science.gov (United States)

Nikolakopoulou, Archontoula; Raptis, Dimitrios; Dracopoulos, Vasilios; Sygellou, Lamprini; Andrikopoulos, Konstantinos S.; Lianos, Panagiotis

2015-03-01

Solid state solar cells of inverted structure were constructed by successive deposition of nanoparticulate titania, antimony sulfide sensitizer and P3HT on FTO electrodes with PEDOT:PSS:Ag as counter electrode. Sensitized photoanode electrodes were characterized by XRD, Raman, XPS, FESEM and UV-vis. Small laboratory scale cells were first constructed and optimized. Functional cells were obtained by annealing the antimony sulfide film either in air or in inert atmosphere. High short-circuit currents were recorded in both cases with air-annealed sample producing more current but lower voltage. Small unit cells were combined to form cell modules. Connection of unit cells in parallel increased current but not proportionally to that of the unit cell. Connection in series preserved current and generated voltage multiplication. Cells were constructed and studied under ambient conditions, without encapsulation. The results encourage upscaling of antimony sulfide solar cells.

Giant hydrogen sulfide plume in the oxygen minimum zone off Peru supports chemolithoautotrophy.

Directory of Open Access Journals (Sweden)

Harald Schunck

Full Text Available In Eastern Boundary Upwelling Systems nutrient-rich waters are transported to the ocean surface, fuelling high photoautotrophic primary production. Subsequent heterotrophic decomposition of the produced biomass increases the oxygen-depletion at intermediate water depths, which can result in the formation of oxygen minimum zones (OMZ. OMZs can sporadically accumulate hydrogen sulfide (H2S, which is toxic to most multicellular organisms and has been implicated in massive fish kills. During a cruise to the OMZ off Peru in January 2009 we found a sulfidic plume in continental shelf waters, covering an area >5500 km(2, which contained ∼2.2×10(4 tons of H2S. This was the first time that H2S was measured in the Peruvian OMZ and with ∼440 km(3 the largest plume ever reported for oceanic waters. We assessed the phylogenetic and functional diversity of the inhabiting microbial community by high-throughput sequencing of DNA and RNA, while its metabolic activity was determined with rate measurements of carbon fixation and nitrogen transformation processes. The waters were dominated by several distinct γ-, δ- and ε-proteobacterial taxa associated with either sulfur oxidation or sulfate reduction. Our results suggest that these chemolithoautotrophic bacteria utilized several oxidants (oxygen, nitrate, nitrite, nitric oxide and nitrous oxide to detoxify the sulfidic waters well below the oxic surface. The chemolithoautotrophic activity at our sampling site led to high rates of dark carbon fixation. Assuming that these chemolithoautotrophic rates were maintained throughout the sulfidic waters, they could be representing as much as ∼30% of the photoautotrophic carbon fixation. Postulated changes such as eutrophication and global warming, which lead to an expansion and intensification of OMZs, might also increase the frequency of sulfidic waters. We suggest that the chemolithoautotrophically fixed carbon may be involved in a negative feedback loop that

Hydrogen Sulfide Sensing through Reactive Sulfur Species (RSS) and Nitroxyl (HNO) in Enterococcus faecalis.

Science.gov (United States)

Shen, Jiangchuan; Walsh, Brenna J C; Flores-Mireles, Ana Lidia; Peng, Hui; Zhang, Yifan; Zhang, Yixiang; Trinidad, Jonathan C; Hultgren, Scott J; Giedroc, David P

2018-05-17

Recent studies of hydrogen sulfide (H 2 S) signaling implicate low molecular weight (LMW) thiol persulfides and other reactive sulfur species (RSS) as signaling effectors. Here, we show that a CstR protein from the human pathogen Enterococcus faecalis ( E. faecalis), previously identified in Staphylococcus aureus ( S. aureus), is an RSS-sensing repressor that transcriptionally regulates a cst-like operon in response to both exogenous sulfide stress and Angeli's salt, a precursor of nitroxyl (HNO). E. faecalis CstR reacts with coenzyme A persulfide (CoASSH) to form interprotomer disulfide and trisulfide bridges between C32 and C61', which negatively regulate DNA binding to a consensus CstR DNA operator. A Δ cstR strain exhibits deficiency in catheter colonization in a catheter-associated urinary tract infection (CAUTI) mouse model, suggesting sulfide regulation and homeostasis is critical for pathogenicity. Cellular polysulfide metabolite profiling of sodium sulfide-stressed E. faecalis confirms an increase in both inorganic polysulfides and LMW thiols and persulfides sensed by CstR. The cst-like operon encodes two authentic thiosulfate sulfurtransferases and an enzyme we characterize here as an NADH and FAD-dependent coenzyme A (CoA) persulfide reductase (CoAPR) that harbors an N-terminal CoA disulfide reductase (CDR) domain and a C-terminal rhodanese homology domain (RHD). Both cysteines in the CDR (C42) and RHD (C508) domains are required for CoAPR activity and complementation of a sulfide-induced growth phenotype of a S. aureus strain lacking cstB, encoding a nonheme Fe II persulfide dioxygenase. We propose that S. aureus CstB and E. faecalis CoAPR employ orthogonal chemistries to lower CoASSH that accumulates under conditions of cellular sulfide toxicity and signaling.

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

The composition of pyrite in volcanogenic massive sulfide deposits as determined with the proton microprobe

International Nuclear Information System (INIS)

Huston, D.L.; Sie, S.H.; Suter, G.F.; Ryan, C.G.

1993-01-01

Pixeprobe analysis of pyrite from Australian volcanogenic massive sulfide (VMS) deposits indicate significant levels of Cu, Zn, Pb, Ba, Ag, Sb, Bi (from inclusions), As, Tl, Mo, Au, In, Cd (from nonstoichiometric substitution), Co, Ni, Se and Te (from stoichiometric substitution). Pyrite in massive sulfide lenses is enriched in trace elements compared to that in the stringer zone owing to hydrothermal recrystallization. Metamorphic recrystallization also 'cleans' pyrite of trace elements. High Au values occur in pyrite with high As content. Pyrite in stringer zones is enriched in Se relative to the overlying massive sulfide lenses and the surrounding alteration zones. (orig.)

Impact of Iron Sulfide Transformation on Trichloroethylene Degradation

Science.gov (United States)

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 enginee...

Simulation for estimation of hydrogen sulfide scavenger injection dose rate for treatment of crude oil

Directory of Open Access Journals (Sweden)

T.M. Elshiekh

2015-12-01

Full Text Available The presence of hydrogen sulfide in the hydrocarbon fluids is a well known problem in many oil and gas fields. Hydrogen sulfide is an undesirable contaminant which presents many environmental and safety hazards. It is corrosive, malodorous, and toxic. Accordingly, a need has been long left in the industry to develop a process which can successfully remove hydrogen sulfide from the hydrocarbons or at least reduce its level during the production, storage or processing to a level that satisfies safety and product specification requirements. The common method used to remove or reduce the concentration of hydrogen sulfide in the hydrocarbon production fluids is to inject the hydrogen sulfide scavenger into the hydrocarbon stream. One of the chemicals produced by the Egyptian Petroleum Research Institute (EPRI is EPRI H2S scavenger. It is used in some of the Egyptian petroleum producing companies. The injection dose rate of H2S scavenger is usually determined by experimental lab tests and field trials. In this work, this injection dose rate is mathematically estimated by modeling and simulation of an oil producing field belonging to Petrobel Company in Egypt which uses EPRI H2S scavenger. Comparison between the calculated and practical values of injection dose rate emphasizes the real ability of the proposed equation.

Nitrite accumulation in continuous-flow partial autotrophic denitrification reactor using sulfide as electron donor.

Science.gov (United States)

Liu, Chunshuang; Li, Wenfei; Li, Xuechen; Zhao, Dongfeng; Ma, Bin; Wang, Yongqiang; Liu, Fang; Lee, Duu-Jong

2017-11-01

The nitrite accumulation in handling nitrate and sulfide-laden wastewater in a continuous-flow upflow anaerobic sludge blanket reactor was studied. At sulfide/nitrate-nitrogen ratio of 1:0.76 and loading rates of 1.2kg-Sm -3 d -1 and 0.4kg-Nm -3 d -1 , the elemental sulfur and nitrite accumulation rates peaked at 90% and 70%, respectively, with Acrobacter, Azoarcus and Thauera presenting the functional strains in the studied reactor. The accumulated nitrite was proposed a promising feedstock for anaerobic ammonia oxidation process. An integrated partial autotrophic denitrification-anaerobic ammonia oxidation-aeration process for handling the ammonia and sulfide-laden wastewaters is proposed for further studies. Copyright © 2017 Elsevier Ltd. All rights reserved.

Transition-Metal-Free Highly Efficient Aerobic Oxidation of Sulfides to Sulfoxides under Mild Conditions

Directory of Open Access Journals (Sweden)

Hua Zhang

2009-12-01

Full Text Available A highly efficient transition-metal-free catalytic system Br2/NaNO2/H2O has been developed for a robust and economic acid-free aerobic oxidation of sulfides. It is noteworthy that the sulfide function reacts under mild conditions without over-oxidation to sulfone. The role of NaNO2as an efficient NO equivalent for the activation of molecular oxygen was identified. Under the optimal conditions, a broad range of sulfide substrates were converted into their corresponding sulfoxides in high yields by molecular oxygen. The present catalytic system utilizes cheap and readily available agents as the catalysts, exhibits high selectivity for sulfoxide products and releases only innocuous water as the by-products.

Dysprosium, the balance problem, and wind power technology

International Nuclear Information System (INIS)

Elshkaki, Ayman; Graedel, T.E.

2014-01-01

Highlights: • We investigate the impacts of the increasing market share of wind power on the demand and supply of REE. • The analysis is carried out using a dynamic material flow and stock model and three scenarios for Dy supply. • The supply of Dy from all deposits will likely lead to an oversupply of the total REEs, Nd, La, Ce and Y. • The supply of Dy from critical REE or Dy rich deposits will likely lead to an oversupply of Ce and Y only. • Large quantities of thorium will be co-produced as a result of Dy demand that needs to be managed carefully. - Abstract: Wind power technology is one of the cleanest electricity generation technologies that are expected to have a substantial share in the future electricity mix. Nonetheless, the expected increase in the market share of wind technology has led to an increasing concern of the availability, production capacity and geographical concentration of the metals required for the technology, especially the rear earth elements (REE) neodymium (Nd) and the far less abundant dysprosium (Dy), and the impacts associated with their production. Moreover, Nd and Dy are coproduced with other rare earth metals mainly from iron, titanium, zirconium, and thorium deposits. Consequently, an increase in the demand for Nd and Dy in wind power technology and in their traditional applications may lead to an increase in the production of the host metals and other companion REE, with possible implications on their supply and demand. In this regard, we have used a dynamic material flow and stock model to study the impacts of the increasing demand for Nd and Dy on the supply and demand of the host metals and other companion REE. In one scenario, when the supply of Dy is covered by all current and expected producing deposits, the increase in the demand for Dy leads to an oversupply of 255 Gg of total REE and an oversupply of the coproduced REE Nd, La, Ce and Y. In the second and third scenarios, however, when the supply of Dy is

Prediction and experimental determination of the solubility of exotic scales at high temperatures - Zinc sulfide

DEFF Research Database (Denmark)

Carolina Figueroa Murcia, Diana; Fosbøl, Philip Loldrup; Thomsen, Kaj

2016-01-01

The presence of "exotic" scale such as Zinc Sulfide (ZnS), Lead Sulfide (PbS) and Iron Sulfide (FeS) in HP/HT reservoirs has been identified. "Exotic" scale materials come as a new challenge in HP/HT reservoirs. This has led to the development of more advanced tools to predict their behavior...... at extreme conditions. The aim of this work is to include ZnS into the group of scale materials that can be modeled with the Extended UNIQUAC model. Solubility data for ZnS are scarce in the open literature. In order to improve the available data, we study the experimental behavior of ZnS solubility at high...... temperatures. The determination of the solubility of ZnS is carried out at temperatures up to 250°C. Zinc sulfide (99.99%) and ultra-pure water are placed in a vial in a reduced oxygen atmosphere. The sample is placed in a controlled bath and stirred until equilibrium is attained. The suspension is filtered...

Pyrolytically grown indium sulfide sensitized zinc oxide nanowires for solar water splitting

Energy Technology Data Exchange (ETDEWEB)

Komurcu, Pelin; Can, Emre Kaan; Aydin, Erkan; Semiz, Levent [Micro and Nanotechnology Graduate Program, TOBB University of Economics and Technology, 06560 Ankara (Turkey); Gurol, Alp Eren; Alkan, Fatma Merve [Department of Materials Science and Nanotechnology Engineering, TOBB University of Economics and Technology, 06560 Ankara (Turkey); Sankir, Mehmet; Sankir, Nurdan Demirci [Micro and Nanotechnology Graduate Program, TOBB University of Economics and Technology, 06560 Ankara (Turkey); Department of Materials Science and Nanotechnology Engineering, TOBB University of Economics and Technology, 06560 Ankara (Turkey)

2015-11-15

Zinc oxide (ZnO) nanowires, sensitized with spray pyrolyzed indium sulfide, were obtained by chemical bath deposition. The XRD analysis indicated dominant evolution of hexagonal ZnO phase. Significant gain in photoelectrochemical current using ZnO nanowires is largely accountable to enhancement of the visible light absorption and the formation of heterostructure. The maximum photoconversion efficiency of 2.77% was calculated for the indium sulfide sensitized ZnO nanowire photoelectrodes. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Enriching distinctive microbial communities from marine sediments via an electrochemical-sulfide-oxidizing process on carbon electrodes

Directory of Open Access Journals (Sweden)

Shiue-Lin eLi

2015-02-01

Full Text Available Sulfide is a common product of marine anaerobic respiration, and a potent reactant biologically and geochemically. Here we demonstrate the impact on microbial communities with the removal of sulfide via electrochemical methods. The use of differential pulse voltammetry revealed that the oxidation of soluble sulfide was seen at + mV (vs. SHE at all pH ranges tested (from pH = 4 to 8, while non-ionized sulfide, which dominated at pH = 4 was poorly oxidized via this process. Two mixed cultures (CAT and LA were enriched from two different marine sediments (from Catalina Island, CAT; from the Port of Los Angeles, LA in serum bottles using a seawater medium supplemented with lactate, sulfate, and yeast extract, to obtain abundant biomass. Both CAT and LA cultures were inoculated in electrochemical cells (using yeast-extract-free seawater medium as an electrolyte equipped with carbon-felt electrodes. In both cases, when potentials of +630 or 130 mV (vs. SHE were applied, currents were consistently higher at +630 then at 0 mV, indicating more sulfide being oxidized at the higher potential. In addition, higher organic-acid and sulfate conversion rates were found at +630 mV with CAT, while no significant differences were found with LA at different potentials. The results of microbial-community analyses revealed a decrease in diversity for both CAT and LA after electrochemical incubation. In addition, some bacteria (e.g., Clostridium and Arcobacter not well known to be capable of extracellular electron transfer, were found to be dominant in the electrochemical cells. Thus, even though the different mixed cultures have different tolerances for sulfide, electrochemical-sulfide removal can lead to major population changes.

Thermodynamics and Kinetics of Sulfide Oxidation by Oxygen: A Look at Inorganically Controlled Reactions and Biologically Mediated Processes in the Environment

Science.gov (United States)

Luther, George W.; Findlay, Alyssa J.; MacDonald, Daniel J.; Owings, Shannon M.; Hanson, Thomas E.; Beinart, Roxanne A.; Girguis, Peter R.

2011-01-01

The thermodynamics for the first electron transfer step for sulfide and oxygen indicates that the reaction is unfavorable as unstable superoxide and bisulfide radical ions would need to be produced. However, a two-electron transfer is favorable as stable S(0) and peroxide would be formed, but the partially filled orbitals in oxygen that accept electrons prevent rapid kinetics. Abiotic sulfide oxidation kinetics improve when reduced iron and/or manganese are oxidized by oxygen to form oxidized metals which in turn oxidize sulfide. Biological sulfur oxidation relies on enzymes that have evolved to overcome these kinetic constraints to affect rapid sulfide oxidation. Here we review the available thermodynamic and kinetic data for H2S and HS• as well as O2, reactive oxygen species, nitrate, nitrite, and NOx species. We also present new kinetic data for abiotic sulfide oxidation with oxygen in trace metal clean solutions that constrain abiotic rates of sulfide oxidation in metal free solution and agree with the kinetic and thermodynamic calculations. Moreover, we present experimental data that give insight on rates of chemolithotrophic and photolithotrophic sulfide oxidation in the environment. We demonstrate that both anaerobic photolithotrophic and aerobic chemolithotrophic sulfide oxidation rates are three or more orders of magnitude higher than abiotic rates suggesting that in most environments biotic sulfide oxidation rates will far exceed abiotic rates due to the thermodynamic and kinetic constraints discussed in the first section of the paper. Such data reshape our thinking about the biotic and abiotic contributions to sulfide oxidation in the environment. PMID:21833317

Removal of Hydrogen Sulfide from Septic Tank by Vermicomposting Bio Filter

Directory of Open Access Journals (Sweden)

Abdol Kazem Neisi

2016-09-01

Full Text Available Background & Aims of the Study: Hydrogen sulfide (H2S is a colorless and highly toxic, easily dissolved in water, flammable and explosive gas. Hydrogen sulfide gas is the main cause of odor emissions from municipal sewage plants. One method for removal of hydrogen sulfide gas is the use of biological systems, biofilter. The aim of this study was to survey removal hydrogen sulfide provide in septic tank by vermicomposting biofilter. Materials and Methods: In this study pilot-scale biofilter has been made of bed vermicompost and wood trash. To survey biofilter performance under real condition, the pilot installed in one wastewater pumping station of Ahwaz city, Iran. The study was carried out over 80 days. Inlet and outlet H2S concentration were measured on regular basis. To provide an optimal condition for bacterial growth, moisture was adjusted between 40% and 60% throughout the experiment. Results: Results showed that H2S concentration emitted from the pumping station during the study varied greatly between 33 and 54ppm .The maximum adsorption capacity of the biological bedding was recorded at 22.4 g/m3.hr and the mean efficiency of H2S removal account the startup time was 89.31% .The mean performance efficiency during the biological activity after the startup was recorded at 96.88%. Conclusion: use up biofilter with vermicompost bed and woodchip is an economic method for H2S removal of septic tanks. Removal efficiency of more than 96% is expected with this method.

One-step liquid phase chemical method to prepare carbon-based amorphous molybdenum sulfides: As the effective hydrogen evolution reaction catalysts

International Nuclear Information System (INIS)

Guo, Mengmeng; Wu, Qikang; Yu, Miaomiao; Wang, Yinling; Li, Maoguo

2017-01-01

Two different kinds of carbon-based amorphous molybdenum sulfide composite catalysts (activated carbon supported amorphous molybdenum sulfide and acetylene black supported amorphous molybdenum sulfide) had been prepared in a facile and scalable one-step liquid phase chemical method. The morphological and structural information of catalysts was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-Ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and it’s electro-catalytic HER activity were evaluated by linear sweep voltammetry(LSV), amperometric i-t technology and AC impedance technology. The as-prepared carbon-based amorphous molybdenum sulfides showed greatly enhanced electro-catalytic activity for HER compared with pure amorphous molybdenum sulfides. Especially, the nano-sized acetylene black supported molybdenum sulfide exhibited excellent electro-catalytic HER performances with a low onset potential of −116 mV versus reverse hydrogen electrode (RHE) and a small Tafel slope of 51 mV per decade.

Disguised as a sulfate reducer: Growth of the Deltaproteobacterium Desulfurivibrio alkaliphilus by Sulfide Oxidation with Nitrate

DEFF Research Database (Denmark)

Thorup, Casper; Schramm, Andreas; Findlay, Alyssa Jean Lehsau

2017-01-01

This study demonstrates that the deltaproteobacterium Desulfurivibrio alkaliphilus can grow chemolithotrophically by coupling sulfide oxidation to the dissimilatory reduction of nitrate and nitrite to ammonium. Key genes of known sulfide oxidation pathways are absent from the genome of D...... of the sulfate reduction pathway. This is the first study providing evidence that a reductive-type DSR is involved in a sulfide oxidation pathway. Transcriptome sequencing further suggests that nitrate reduction to ammonium is performed by a novel type of periplasmic nitrate reductase and an unusual membrane......-anchored nitrite reductase....

Studies on silicone based antifoaming agents to be used in G.S. (Girlder sulfide) heavy water plants

International Nuclear Information System (INIS)

Delfino, C.A.

1986-01-01

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) [es

Antifoaming materials studies in G.S. (Girlder sulfide) heavy water plants. Chemical and thermical stability. Pt. 3

International Nuclear Information System (INIS)

Delfino, C.A.; Rojo, E.A.

1988-01-01

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) [es

Long-term effects of sulfidized silver nanoparticles in sewage sludge on soil microflora.

Science.gov (United States)

Kraas, Marco; Schlich, Karsten; Knopf, Burkhard; Wege, Franziska; Kägi, Ralf; Terytze, Konstantin; Hund-Rinke, Kerstin

2017-12-01

The use of silver nanoparticles (AgNPs) in consumer products such as textiles leads to their discharge into wastewater and consequently to a transfer of the AgNPs to soil ecosystems via biosolids used as fertilizer. In urban wastewater systems (e.g., sewer, wastewater treatment plant [WWTP], anaerobic digesters) AgNPs are efficiently converted into sparingly soluble silver sulfides (Ag 2 S), mitigating the toxicity of the AgNPs. However, long-term studies on the bioavailability and effects of sulfidized AgNPs on soil microorganisms are lacking. Thus we investigated the bioavailability and long-term effects of AgNPs (spiked in a laboratory WWTP) on soil microorganisms. Before mixing the biosolids into soil, the sludges were either anaerobically digested or directly dewatered. The effects on the ammonium oxidation process were investigated over 140 d. Transmission electron microscopy (TEM) suggested an almost complete sulfidation of the AgNPs analyzed in all biosolid samples and in soil, with Ag 2 S predominantly detected in long-term incubation experiments. However, despite the sulfidation of the AgNPs, soil ammonium oxidation was significantly inhibited, and the degree of inhibition was independent of the sludge treatment. The results revealed that AgNPs sulfidized under environmentally relevant conditions were still bioavailable to soil microorganisms. Consequently, Ag 2 S may exhibit toxic effects over the long term rather than the short term. Environ Toxicol Chem 2017;36:3305-3313. © 2017 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC. © 2017 The Authors. Environmental Toxicology and Chemistry Published by Wiley Periodicals, Inc. on behalf of SETAC.

Elevated corrosion rates and hydrogen sulfide in homes with 'Chinese Drywall'

Energy Technology Data Exchange (ETDEWEB)

Allen, Joseph G.; MacIntosh, David L. [Environmental Health and Engineering, Inc., 117 Fourth Avenue, Needham, MA (United States); Harvard School of Public Health, 677 Huntington Avenue, Boston, MA (United States); Saltzman, Lori E. [U.S. Consumer Product Safety Commission, Bethesda, MD (United States); Baker, Brian J. [Environmental Health and Engineering, Inc., 117 Fourth Avenue, Needham, MA (United States); Matheson, Joanna M.; Recht, Joel R. [U.S. Consumer Product Safety Commission, Bethesda, MD (United States); Minegishi, Taeko; Fragala, Matt A.; Myatt, Theodore A. [Environmental Health and Engineering, Inc., 117 Fourth Avenue, Needham, MA (United States); Spengler, John D.; Stewart, James H. [Environmental Health and Engineering, Inc., 117 Fourth Avenue, Needham, MA (United States); Harvard School of Public Health, 677 Huntington Avenue, Boston, MA (United States); McCarthy, John F., E-mail: jmcccarthy@eheinc.com [Environmental Health and Engineering, Inc., 117 Fourth Avenue, Needham, MA (United States)

2012-06-01

In December 2008, the U.S. Consumer Product Safety Commission (CPSC) began receiving reports about odors, corrosion, and health concerns related to drywall originating from China. In response, a detailed environmental health and engineering evaluation was conducted of 41 complaint and 10 non-complaint homes in the Southeast U.S. Each home investigation included characterization of: 1) drywall composition; 2) indoor and outdoor air quality; 3) temperature, moisture, and building ventilation; and 4) copper and silver corrosion rates. Complaint homes had significantly higher hydrogen sulfide concentrations (mean 0.82 vs. < LOD {mu}g/m{sup 3}, p < 0.05), and significantly greater rates of copper sulfide and silver sulfide corrosion compared to non-complaint homes (Cu{sub 2}S: 476 vs. < 32 A/30 d, p < 0.01; Ag{sub 2}S: 1472 vs. 389 A/30 d, p < 0.01). The abundance of carbonate and strontium in drywall was also elevated in complaint homes, and appears to be useful objective marker of problematic drywall in homes that meet other screening criteria (e.g., constructed or renovated in 2006-2007, reports of malodor and accelerated corrosion). This research provides empirical evidence of the direct association between homes constructed with 'Chinese Drywall' in 2006-2007 and elevated corrosion rates and hydrogen sulfide concentrations in indoor air. - Highlights: Black-Right-Pointing-Pointer Environmental measurements in homes with and without 'Chinese Drywall' Black-Right-Pointing-Pointer Homes with 'Chinese Drywall' had higher hydrogen sulfide concentrations Black-Right-Pointing-Pointer Homes with 'Chinese Drywall' had elevated corrosion rates Black-Right-Pointing-Pointer Study provides empirical evidence of reported associations.

Thioamides as collectors at flotation of sulfide minerals

International Nuclear Information System (INIS)

Fomin, B.M.; Solozhenkin, P.M.; Rukhadze, E.G.; Lyubavina, L.L.

1976-01-01

The collective properties of thioamides at flotation of number of sulfide minerals are considered. It is defined that studied thioamides fix on the surface of minerals with formation of appropriate complexes. The spectres of copper thioamides are studied by means of electron paramagnetic resonance and infrared spectroscopy.

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.

Colorless sulfur-oxidizing bacteria are ubiquitous in Indian waters and have the ability to oxidize sulfide under anaerobic conditions. These bacteria can not only mediate the sulfur cycle oxidatively but also the nitrogen cycle reductively without...

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.

Alternative waste residue materials for passive in situ prevention of sulfide-mine tailings oxidation: a field evaluation.

Science.gov (United States)

Nason, Peter; Johnson, Raymond H; Neuschütz, Clara; Alakangas, Lena; Öhlander, Björn

2014-02-28

Novel solutions for sulfide-mine tailings remediation were evaluated in field-scale experiments on a former tailings repository in northern Sweden. Uncovered sulfide-tailings were compared to sewage-sludge biosolid amended tailings over 2 years. An application of a 0.2m single-layer sewage-sludge amendment was unsuccessful at preventing oxygen ingress to underlying tailings. It merely slowed the sulfide-oxidation rate by 20%. In addition, sludge-derived metals (Cu, Ni, Fe, and Zn) migrated and precipitated at the tailings-to-sludge interface. By using an additional 0.6m thick fly-ash sealing layer underlying the sewage sludge layer, a solution to mitigate oxygen transport to the underlying tailings and minimize sulfide-oxidation was found. The fly-ash acted as a hardened physical barrier that prevented oxygen diffusion and provided a trap for sludge-borne metals. Nevertheless, the biosolid application hampered the application, despite the advances in the effectiveness of the fly-ash layer, as sludge-borne nitrate leached through the cover system into the underlying tailings, oxidizing pyrite. This created a 0.3m deep oxidized zone in 6-years. This study highlights that using sewage sludge in unconventional cover systems is not always a practical solution for the remediation of sulfide-bearing mine tailings to mitigate against sulfide weathering and acid rock drainage formation. Copyright © 2014 Elsevier B.V. All rights reserved.

Carbon nanotube/metal-sulfide composite flexible electrodes for high-performance quantum dot-sensitized solar cells and supercapacitors.

Science.gov (United States)

Muralee Gopi, Chandu V V; Ravi, Seenu; Rao, S Srinivasa; Eswar Reddy, Araveeti; Kim, Hee-Je

2017-04-19

Carbon nanotubes (CNT) and metal sulfides have attracted considerable attention owing to their outstanding properties and multiple application areas, such as electrochemical energy conversion and energy storage. Here we describes a cost-effective and facile solution approach to the preparation of metal sulfides (PbS, CuS, CoS, and NiS) grown directly on CNTs, such as CNT/PbS, CNT/CuS, CNT/CoS, and CNT/NiS flexible electrodes for quantum dot-sensitized solar cells (QDSSCs) and supercapacitors (SCs). X-ray photoelectron spectroscopy, X-ray diffraction, and transmission electron microscopy confirmed that the CNT network was covered with high-purity metal sulfide compounds. QDSSCs equipped with the CNT/NiS counter electrode (CE) showed an impressive energy conversion efficiency (η) of 6.41% and remarkable stability. Interestingly, the assembled symmetric CNT/NiS-based polysulfide SC device exhibited a maximal energy density of 35.39 W h kg -1 and superior cycling durability with 98.39% retention after 1,000 cycles compared to the other CNT/metal-sulfides. The elevated performance of the composites was attributed mainly to the good conductivity, high surface area with mesoporous structures and stability of the CNTs and the high electrocatalytic activity of the metal sulfides. Overall, the designed composite CNT/metal-sulfide electrodes offer an important guideline for the development of next level energy conversion and energy storage devices.

Influence of intramolecular f-f interactions on nuclear spin driven quantum tunneling of magnetizations in quadruple-decker phthalocyanine complexes containing two terbium or dysprosium magnetic centers.

Science.gov (United States)

Fukuda, Takamitsu; Matsumura, Kazuya; Ishikawa, Naoto

2013-10-10

Nuclear spin driven quantum tunneling of magnetization (QTM) phenomena, which arise from admixture of more than two orthogonal electronic spin wave functions through the couplings with those of the nuclear spins, are one of the important magnetic relaxation processes in lanthanide single molecule magnets (SMMs) in the low temperature range. Although recent experimental studies have indicated that the presence of the intramolecular f-f interactions affects their magnetic relaxation processes, little attention has been given to their mechanisms and, to the best of our knowledge, no rational theoretical models have been proposed for the interpretations of how the nuclear spin driven QTMs are influenced by the f-f interactions. Since quadruple-decker phthalocyanine complexes with two terbium or dysprosium ions as the magnetic centers show moderate f-f interactions, these are appropriate to investigate the influence of the f-f interactions on the dynamic magnetic relaxation processes. In the present paper, a theoretical model including ligand field (LF) potentials, hyperfine, nuclear quadrupole, magnetic dipolar, and the Zeeman interactions has been constructed to understand the roles of the nuclear spins for the QTM processes, and the resultant Zeeman plots are obtained. The ac susceptibility measurements of the magnetically diluted quadruple-decker monoterbium and diterbium phthalocyanine complexes, [Tb-Y] and [Tb-Tb], have indicated that the presence of the f-f interactions suppresses the QTMs in the absence of the external magnetic field (H(dc)) being consistent with previous reports. On the contrary, the faster magnetic relaxation processes are observed for [Tb-Tb] than [Tb-Y] at H(dc) = 1000 Oe, clearly demonstrating that the QTMs are rather enhanced in the presence of the external magnetic field. Based on the calculated Zeeman diagrams, these observations can be attributed to the enhanced nuclear spin driven QTMs for [Tb-Tb]. At the H(dc) higher than 2000 Oe, the

The effect of sulfide on the aerobic corrosion of carbon steel in near-neutral pH saline solutions

International Nuclear Information System (INIS)

Sherar, B.W.A.; Keech, P.G.; Shoesmith, D.W.

2013-01-01

Highlights: ► The corrosion rate is low when steel is exposed to anaerobic conditions (pH = 8.9). ► An anaerobic to aerobic corrosion with sulfide switch increases the corrosion rate. ► Aerobic exposure induces the formation of goethite-covered tubercles. ► Continual sulfide exposure leads to the slow conversion of goethite to mackinawite. - Abstract: Severe corrosion damage may occur when gas transmission pipelines are exposed, at disbonded coating locations, to trapped waters containing sulfide followed by secondary exposure to air. Aerobic corrosion with sulfide was investigated in a long-term corrosion experiment in which corrosion was monitored by measurement of the corrosion potential and polarization resistance obtained from linear polarization resistance measurements. The properties and composition of the corrosion product deposits formed were determined using scanning electron microscopy, energy dispersive X-ray analysis, and Raman spectroscopy. A switch from aerobic to aerobic-with-sulfide corrosion doubles the relative corrosion rate.

Respiratory responses of the air-breathing fish Hoplosternum littorale to hypoxia and hydrogen sulfide.

Science.gov (United States)

Affonso, E G; Rantin, F T

2005-07-01

The present study analyzes the respiratory responses of the neotropical air-breathing fish Hoplosternum littorale to graded hypoxia and increased sulfide concentrations. The oxygen uptake (VO2), critical O2 tension (PcO2), respiratory (fR) and air-breathing (fRA) frequencies in response to graded hypoxia were determined for fish acclimated to 28 degrees C. H. littorale was able to maintain a constant VO2 down to a PcO2 of 50 mm Hg, below which fish became dependent on the environmental O2 even with significant increases in fR. The fRA was kept constant around 1 breath h(-1) above 50 mm Hg and increased significantly below 40 mm Hg, reaching maximum values (about 4.5 breaths h(-1)) at 10 mm Hg. The lethality to sulfide concentrations under normoxic and hypoxic conditions were also determined along with the fRA. For the normoxic fish the sulfide lethal limit was about 70 microM, while in the hypoxic ones this limit increased to 87 muM. The high sulfide tolerance of H. littorale may be attributed to the air-breathing capability, which is stimulated by this compound.

Optimum injection dose rate of hydrogen sulfide scavenger for treatment of petroleum crude oil

Directory of Open Access Journals (Sweden)

T.M. Elshiekh

2016-03-01

Full Text Available Hydrogen sulfide H2S scavengers are chemicals that favorably react with hydrogen sulfide gas to eliminate it and produce environmental friendly products. These products depend on the type and composition of the scavenger and the conditions at which the reaction takes place. The scavenger should be widely available and economical for industry acceptance by having a low unit cost. The optimum values of H2S scavenger injection dose rate of scavenging hydrogen sulfide from the multiphase fluid produced at different wells conditions in one of the Petroleum Companies in Egypt were studied. The optimum values of H2S scavenger injection dose rate depend on pipe diameter, pipe length, gas molar mass velocity, inlet H2S concentration and pressure. The optimization results are obtained for different values of these parameters using the software program Lingo. In general, the optimum values of H2S scavenger injection dose rate of the scavenging of hydrogen sulfide are increased by increasing of the pipe diameter and increasing the inlet H2S concentration, and decreased by increasing the pipe length, gas molar mass velocity and pressure.

In situ recovery of copper from sulfide ore bodies following nuclear fracturing

Energy Technology Data Exchange (ETDEWEB)

Rosenbaum, Joe B; McKinney, W A [Salt Lake City Metallurgy Research Center, Bureau of Mines, US Department of the Interior, Salt Lake City, UT (United States)

1970-05-15

Leaching now yields about 12 percent of the Nation's annual new copper production. About 200,000 tons of copper a year is being won by heap and vat leaching of ore, dump leaching of waste, and in-place leaching of caved underground workings. Although in-place leaching was practiced as long ago as the 15th century, it is little used and contributes only a few percent of the total leach copper production. Current technology in this area is exemplified by practice at the Miami, Ariz., mine of the Miami Copper Co. Despite its limited use, the concept of extracting copper by in-place leaching without physically mining and transporting the ore continues to present intriguing cost saving possibilities. Project SLOOP has been proposed as an experiment to test the feasibility of nuclear fracturing and acid leaching the oxidized portion of a deep ore body near Safford, Ariz. However, the bulk of the copper in deep ore deposits occurs as sulfide minerals that are not easily soluble in acid solutions. This paper explores the concept of in-place leaching of nuclear fractured, deeply buried copper sulfide deposits. On the assumption that fracturing of rock and solution injection and collection would be feasible, an assessment is made of solution systems that might be employed for the different copper sulfide minerals in porphyry ore bodies. These include the conventional ferric sulfate-sulfuric acid systems and combinations of sulfide mineral oxidants and different acids. (author)

In situ recovery of copper from sulfide ore bodies following nuclear fracturing

International Nuclear Information System (INIS)

Rosenbaum, Joe B.; McKinney, W.A.

1970-01-01

Leaching now yields about 12 percent of the Nation's annual new copper production. About 200,000 tons of copper a year is being won by heap and vat leaching of ore, dump leaching of waste, and in-place leaching of caved underground workings. Although in-place leaching was practiced as long ago as the 15th century, it is little used and contributes only a few percent of the total leach copper production. Current technology in this area is exemplified by practice at the Miami, Ariz., mine of the Miami Copper Co. Despite its limited use, the concept of extracting copper by in-place leaching without physically mining and transporting the ore continues to present intriguing cost saving possibilities. Project SLOOP has been proposed as an experiment to test the feasibility of nuclear fracturing and acid leaching the oxidized portion of a deep ore body near Safford, Ariz. However, the bulk of the copper in deep ore deposits occurs as sulfide minerals that are not easily soluble in acid solutions. This paper explores the concept of in-place leaching of nuclear fractured, deeply buried copper sulfide deposits. On the assumption that fracturing of rock and solution injection and collection would be feasible, an assessment is made of solution systems that might be employed for the different copper sulfide minerals in porphyry ore bodies. These include the conventional ferric sulfate-sulfuric acid systems and combinations of sulfide mineral oxidants and different acids. (author)

Amorphous nickel/cobalt tungsten sulfide electrocatalysts for high-efficiency hydrogen evolution reaction

Energy Technology Data Exchange (ETDEWEB)

Yang, Lun [Key Laboratory of Modern Acoustics, MOE, Institute of Acoustics and Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093 (China); Wu, Xinglong, E-mail: hkxlwu@nju.edu.cn [Key Laboratory of Modern Acoustics, MOE, Institute of Acoustics and Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093 (China); Department of Physics, NingBo University, NingBo 315001 (China); Zhu, Xiaoshu [Center for Analysis and Testing, Nanjing Normal University, Nanjing 210093 (China); He, Chengyu; Meng, Ming; Gan, Zhixing [Key Laboratory of Modern Acoustics, MOE, Institute of Acoustics and Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093 (China); Chu, Paul K. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China)

2015-06-30

Graphical abstract: - Highlights: • Amorphous nickel/cobalt tungsten sulfides were synthesized by a thermolytic process. • Amorphous NiWS and CoWS could realize hydrogen evolution efficiently. • Ni/Co promotion and annealing alter the porous structure and chemical bonding states. • Active sites on the surface of amorphous WS{sub x} are increased with Ni or Co doping. • Amorphous NiWS and CoWS have immense potentials in water splitting devices. - Abstract: The hydrogen evolution reaction (HER), an appealing solution for future energy supply, requires efficient and inexpensive electrocatalysts with abundant active surface sites. Although crystalline MoS{sub 2} and WS{sub 2} are promising candidates, their activity is dominated by edge sites. Amorphous tungsten sulfide prepared so far lacks the required active sites and its application has thus been hampered. In this work, nickel and cobalt incorporated amorphous tungsten sulfide synthesized by a thermolytic process is demonstrated to enhance the HER efficiency dramatically. The amorphous nickel tungsten sulfide (amorphous NiWS) annealed at 210 °C delivers the best HER performance in this system boasting a Tafel slope of 55 mV per decade and current density of 8.6 mA cm{sup −2} at 250 mV overpotential in a sustained test for 24 h. The introduction of Ni or Co into the catalyst and subsequent thermal treatment alters the porous structure and chemical bonding states thereby increasing the density of active sites on the surface.

The mechanism of the catalytic oxidation of hydrogen sulfide: II. Kinetics and mechanism of hydrogen sulfide oxidation catalyzed by sulfur

NARCIS (Netherlands)

Steijns, M.; Derks, F.; Verloop, A.; Mars, P.

1976-01-01

The kinetics of the catalytic oxidation of hydrogen sulfide by molecular oxygen have been studied in the temperature range 20–250 °C. The primary reaction product is sulfur which may undergo further oxidation to SO2 at temperatures above 200 °C. From the kinetics of this autocatalytic reaction we

Iridium Sulfide and Ir Promoted Mo Based Catalysts.

Czech Academy of Sciences Publication Activity Database

Vít, Zdeněk

2007-01-01

Roč. 322, - (2007), s. 142-151 ISSN 0926-860X R&D Projects: GA ČR(CZ) GA104/06/0870 Institutional research plan: CEZ:AV0Z40720504 Keywords : iridium sulfide * IrMo catalyst * hydrodesulfurization Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.166, year: 2007

75 FR 19319 - Hydrogen Sulfide; Community Right-to-Know Toxic Chemical Release Reporting; Extension of Comment...

Science.gov (United States)

2010-04-14

... Hydrogen Sulfide; Community Right-to-Know Toxic Chemical Release Reporting; Extension of Comment Period... reporting requirements for hydrogen sulfide (Chemical Abstracts Service Number (CAS No.) 7783-06-4) (75 FR... may be potentially affected by this action if you manufacture, process, or otherwise use hydrogen...

Neutron activation determination of gold and palladium using extraction by organic sulfides

International Nuclear Information System (INIS)

Gil'berg, Eh.N.; Torgov, V.G.; Verevkin, G.V.; AN SSSR, Novosibirsk. Inst. Neorganicheskoj Khimii)

1978-01-01

Compared are methods of gold determination in standard rock samples of the USA National Geological Service: a) extraction by solutions of dioctylsulfide and oil sulfides from irradiated samples; b) preliminary extraction by the above solfides with the following extract radiation; c) the method of isotope dilution with substoichiometry extraction. A possibility is studied to determine palladium in the sulfide extract with gold using the NaI(Tl) thin crystal scintillators. It is established that joint palladium and gold extraction permits to determine them in many natural products simultaneously

Carbon steel protection in G.S. (Girlder sulfide) plants. Iron sulfide scales formation on surfaces covered by fabrication produced films. Pt. 4

International Nuclear Information System (INIS)

Burkart, A.L.

1986-04-01

This work describes the assays aimed to passivate the steel carbon of the process pipings. This steel is marked by the ASTM A 333 G6 and is chemically similar to those of isotopic exchange towers which corrode in contact with in-water hydrogen sulfide solutions forming iron sulfide protective layers. The differences between both materials lie in the surface characteristics to be passivated. The steel of towers has an internal side covered by paint which shall be removed prior to passivation. The steel's internal side shall be covered by a film formed during the fabrication process and constituted by calcinated wastes and iron oxides (magnetite, hematite and wustite). This film interferes in the formation process of passivating layers of pyrrhotite and pyrite. The possibility to passivate the pipes in their actual state was evaluated since it would result highly laborious and expensive to eliminate the film. (Author) [es

Studies on ternary silver sulfides; Fukugo gin ryukabutsu ni kansuru kenkyu

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-10-31

Some sulfides containing silver show high ion mobility based on movability of silver, whose application is expected. Studies have been carried out centrally on synthesis of new compounds of ternary silver sulfides by elucidating the relationship among their compositions, structures and properties by means of crystal chemical studies mainly on their phase relationship. A few new compounds have been synthesized, such as the ones having the argyrodite family compound structure including transition metals. The synthesizing process takes a kind of turbulent liquid state structure at elevated temperatures because of movability of silver, but silver is fixed at low temperatures in different sites between skeleton structures made by other atoms. These studies on phase transfer, structures, and silver movability have been based on X-ray diffraction, infrared and Raman spectroscopic measurements, NMR, measurements of electric and thermal characteristics. For the studies related to compositions and structures of ternary metal sulfides which take compound crystalline structure, a structure analyzing method based on multi-dimensional hyperspatial groups was used. This paper reports the summary of the studies in seven chapters, and dwells on the remaining problems and future prospects. 158 refs., 114 figs., 65 tabs.

Long-term corrosion of copper in a dilute anaerobic sulfide solution

Energy Technology Data Exchange (ETDEWEB)

Chen, J.; Qin, Z. [Department of Chemistry, University of Western Ontario, London, Ontario, N6A 5B7 (Canada); Shoesmith, D.W., E-mail: dwshoesm@uwo.ca [Department of Chemistry, University of Western Ontario, London, Ontario, N6A 5B7 (Canada)

2011-09-30

The mechanism of corrosion of oxygen-free copper has been studied in stagnant aqueous sulfide solutions using corrosion potential and electrochemical impedance spectroscopy (EIS) measurements. Film structure and composition were examined on surfaces and on cross-sections prepared by focused ion beam (FIB) milling using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Experiments were conducted in anaerobic 5 x 10{sup -5} mol dm{sup -3} Na{sub 2}S + 0.1 mol dm{sup -3} NaCl solutions for exposure periods up to 4000 h ({approx}167 days) to mimic (at least partially) the conditions that could develop on a copper nuclear fuel waste container in a deep geologic repository. The corrosion film formed was a single cellular Cu{sub 2}S layer with a non-uniform thickness. The film thickness increased approximately linearly with immersion time, which implied that the sulfide film formed on the Cu surface is non-protective under these conditions up to this exposure time. The film growth process was controlled by HS{sup -} diffusion partially in the aqueous solution in the pores in the cellular sulfide film and partially in the bulk of the aqueous solution.

A batch assay to measure microbial hydrogen sulfide production from sulfur-containing solid wastes

International Nuclear Information System (INIS)

Sun, Mei; Sun, Wenjie; Barlaz, Morton A.

2016-01-01

Large volumes of sulfur-containing wastes enter municipal solid waste landfills each year. Under the anaerobic conditions that prevail in landfills, oxidized forms of sulfur, primarily sulfate, are converted to sulfide. Hydrogen sulfide (H 2 S) is corrosive to landfill gas collection and treatment systems, and its presence in landfill gas often necessitates the installation of expensive removal systems. For landfill operators to understand the cost of managing sulfur-containing wastes, an estimate of the H 2 S production potential is needed. The objective of this study was to develop and demonstrate a biochemical sulfide potential (BSP) test to measure the amount of H 2 S produced by different types of sulfur-containing wastes in a relatively fast (30 days) and inexpensive (125 mL serum bottles) batch assay. This study confirmed the toxic effect of H 2 S on both sulfate reduction and methane production in batch systems, and demonstrated that removing accumulated H 2 S by base adsorption was effective for mitigating inhibition. H 2 S production potentials of coal combustion fly ash, flue gas desulfurization residual, municipal solid waste combustion ash, and construction and demolition waste were determined in BSP assays. After 30 days of incubation, most of the sulfate in the wastes was converted to gaseous or aqueous phase sulfide, with BSPs ranging from 0.8 to 58.8 mL H 2 S/g waste, depending on the chemical composition of the samples. Selected samples contained solid phase sulfide which contributed to the measured H 2 S yield. A 60 day incubation in selected samples resulted in 39–86% additional sulfide production. H 2 S production measured in BSP assays was compared with that measured in simulated landfill reactors and that calculated from chemical analyses. H 2 S production in BSP assays and in reactors was lower than the stoichiometric values calculated from chemical composition for all wastes tested, demonstrating the importance of assays to estimate the

Evaluation of biological hydrogen sulfide oxidation coupled with two-stage upflow filtration for groundwater treatment.

Science.gov (United States)

Levine, Audrey D; Raymer, Blake J; Jahn, Johna

2004-01-01

Hydrogen sulfide in groundwater can be oxidized by aerobic bacteria to form elemental sulfur and biomass. While this treatment approach is effective for conversion of hydrogen sulfide, it is important to have adequate control of the biomass exiting the biological treatment system to prevent release of elemental sulfur into the distribution system. Pilot scale tests were conducted on a Florida groundwater to evaluate the use of two-stage upflow filtration downstream of biological sulfur oxidation. The combined biological and filtration process was capable of excellent removal of hydrogen sulfide and associated turbidity. Additional benefits of this treatment approach include elimination of odor generation, reduction of chlorine demand, and improved stability of the finished water.

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.

Mixed Cd-Zn sulfides / Pt-TiO2 composites : bottlenecks limiting efficiency of photocatalytic water reduction

NARCIS (Netherlands)

Litke, A.; Weber, Th.; Hofmann, J.P.; Hensen, E.J.M.

2016-01-01

Visible-light driven photocatalytic water reduction on composite materials consisting of platinized titania (Pt-TiO2) and transition metal sulfides (CdS or Cd0.5Zn0.5S) was investigated in detail. Sulfides were prepared by hydrothermal synthesis and room-temperature precipitation. The parameters

Metagenome-based metabolic reconstruction reveals the ecophysiological function of Epsilonproteobacteria in a hydrocarbon-contaminated sulfidic aquifer

Directory of Open Access Journals (Sweden)

Andreas Hardy Keller

2015-12-01

Full Text Available The population genome of an uncultured bacterium assigned to the Campylobacterales (Epsilonproteobacteria was reconstructed from a metagenome dataset obtained by whole-genome shotgun pyrosequencing. Genomic DNA was extracted from a sulfate-reducing, m-xylene-mineralizing enrichment culture isolated from groundwater of a benzene-contaminated sulfidic aquifer. The identical epsilonproteobacterial phylotype has previously been detected in toluene- or benzene-mineralizing, sulfate-reducing consortia enriched from the same site. Previous stable isotope probing experiments with 13C6-labeled benzene suggested that this phylotype assimilates benzene-derived carbon in a syntrophic benzene-mineralizing consortium that uses sulfate as terminal electron acceptor. However, the type of energy metabolism and the ecophysiological function of this epsilonproteobacterium within aromatic hydrocarbon-degrading consortia and in the sulfidic aquifer are poorly understood.Annotation of the epsilonproteobacterial population genome suggests that the bacterium plays a key role in sulfur cycling as indicated by the presence of a sqr gene encoding a sulfide quinone oxidoreductase and psr genes encoding a polysulfide reductase. It may gain energy by using sulfide or hydrogen/formate as electron donors. Polysulfide, fumarate, as well as oxygen are potential electron acceptors. Auto- or mixotrophic carbon metabolism seems plausible since a complete reductive citric acid cycle was detected. Thus the bacterium can thrive in pristine groundwater as well as in hydrocarbon-contaminated aquifers. In hydrocarbon-contaminated sulfidic habitats, the epsilonproteobacterium may generate energy by coupling the oxidation of hydrogen or formate and highly abundant sulfide with the reduction of fumarate and/or polysulfide, accompanied by efficient assimilation of acetate produced during fermentation or incomplete oxidation of hydrocarbons. The highly efficient assimilation of acetate was

Metagenome-Based Metabolic Reconstruction Reveals the Ecophysiological Function of Epsilonproteobacteria in a Hydrocarbon-Contaminated Sulfidic Aquifer.

Science.gov (United States)

Keller, Andreas H; Schleinitz, Kathleen M; Starke, Robert; Bertilsson, Stefan; Vogt, Carsten; Kleinsteuber, Sabine

2015-01-01

The population genome of an uncultured bacterium assigned to the Campylobacterales (Epsilonproteobacteria) was reconstructed from a metagenome dataset obtained by whole-genome shotgun pyrosequencing. Genomic DNA was extracted from a sulfate-reducing, m-xylene-mineralizing enrichment culture isolated from groundwater of a benzene-contaminated sulfidic aquifer. The identical epsilonproteobacterial phylotype has previously been detected in toluene- or benzene-mineralizing, sulfate-reducing consortia enriched from the same site. Previous stable isotope probing (SIP) experiments with (13)C6-labeled benzene suggested that this phylotype assimilates benzene-derived carbon in a syntrophic benzene-mineralizing consortium that uses sulfate as terminal electron acceptor. However, the type of energy metabolism and the ecophysiological function of this epsilonproteobacterium within aromatic hydrocarbon-degrading consortia and in the sulfidic aquifer are poorly understood. Annotation of the epsilonproteobacterial population genome suggests that the bacterium plays a key role in sulfur cycling as indicated by the presence of an sqr gene encoding a sulfide quinone oxidoreductase and psr genes encoding a polysulfide reductase. It may gain energy by using sulfide or hydrogen/formate as electron donors. Polysulfide, fumarate, as well as oxygen are potential electron acceptors. Auto- or mixotrophic carbon metabolism seems plausible since a complete reductive citric acid cycle was detected. Thus the bacterium can thrive in pristine groundwater as well as in hydrocarbon-contaminated aquifers. In hydrocarbon-contaminated sulfidic habitats, the epsilonproteobacterium may generate energy by coupling the oxidation of hydrogen or formate and highly abundant sulfide with the reduction of fumarate and/or polysulfide, accompanied by efficient assimilation of acetate produced during fermentation or incomplete oxidation of hydrocarbons. The highly efficient assimilation of acetate was recently

Differential responses of the freshwater wetland species Juncus effusus L. and Caltha palustris L. to iron supply in sulfidic environments

International Nuclear Information System (INIS)

Welle, Marlies E.W. van der; Niggebrugge, Karla; Lamers, Leon P.M.; Roelofs, Jan G.M.

2007-01-01

Sulfur pollution can lead to serious problems in freshwater wetlands, including phosphorus eutrophication and sulfide toxicity. We tested the effects of anaerobic iron-rich groundwater discharge in fens, simulated by iron injection, on two characteristic species (Juncus effusus and Caltha palustris) in a sulfidic environment. Biomass production of C. palustris roots showed an optimum response to the combined addition of iron and sulfide, with highest values at intermediate concentrations of both substances. Iron deficiency apparently occurred at low iron concentrations, while at high iron concentrations, growth was decreased. For J. effusus, in contrast, no toxic effects were found of both iron and sulfide. This could be explained by larger radial oxygen loss (ROL) of J. effusus and could not be explained by differences in phosphorous concentrations. The results of our experiments confirm that iron-rich groundwater discharge has the potential to affect vegetation composition through toxicity modification in sulfidic environments. - Toxicity of iron and sulfide are interacting with each other and have the potential to affect vegetation composition

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.

Oxidation-sulfidation behavior of Ni aluminide in oxygen-sulfur mixed-gas atmospheres

International Nuclear Information System (INIS)

Natesan, K.

1988-01-01

Oxidation-sulfidation studies were conducted with sheet samples of nickel aluminide, containing 23.5 at. % Al, 0.5 at. % Hf, and 0.2 at. % B, in an annealed condition and after preoxidation treatments. Continuous weight-change measurements were made by a thermogravimetric technique in exposure atmospheres of air, a low-pO/sub 2/ gas mixture, and low-pO/sub 2/ gas mixtures with several levels of sulfur. The air-exposed specimens developed predominantly nickel oxide; the specimen exposed to a low-pO/sub 2/ environment developed an aluminum oxide scale. As the sulfur content of the gas mixture increased, the alumina scale exhibited spallation and the alloy tended to form nickel sulfide as the reaction phase. The results indicated that the sulfidation reaction of nickel aluminide specimens (both bare and preoxidized) was determined by the rate of transport of nickel from the substrate through the scale to the gas/alumina scale interface, the mechanical integrity of the oxide scale, and the H/sub 2/S concentration in the exposure environment

Preparation and characterization of polyaniline-cadmium sulfide nanocomposite for gas sensor application

Science.gov (United States)

Al-Jawad, Selma M. H.; Rafic, Sewench N.; Muhsen, Mustafa M.

2017-09-01

Polyaniline (PANI) was prepared by chemical oxidative polymerization of aniline monomers as emeraldine salt form. By the same method, polyaniline-cadmium sulfide nanocomposites were synthesized in the presence of different percentages (10-50 wt.%) of cadmium sulfide (CdS) which was prepared by using sol-gel method. The optical band gap was decrease with increasing of CdS concentration, that is obtained from UV-VIS measurements. From SEM and AFM, there is uniform distribution for cadmium sulfide nanoparticles in the PANI matrix. The electrical measurements of nanocomposites exhibit the effect of crystallite size and the high resistivity of CdS on the resistivity of nanocomposites. Emeraldine salt PANI, CdS and PANI-CdS nanocomposites were investigated as gas sensors. From this investigation, the sensitivity of PANI-CdS for NO2 gas increase with the increasing of operation temperature and the optimum sensitivity was obtained at 200∘C. The sensitivity of nanocomposites at best temperature (200∘C) was increased and faster response time with the increasing of CdS contents.

Evaluation of feed COD/sulfate ratio as a control criterion for the biological hydrogen sulfide production and lead precipitation

International Nuclear Information System (INIS)

Velasco, Antonio; Ramirez, Martha; Volke-Sepulveda, Tania; Gonzalez-Sanchez, Armando; Revah, Sergio

2008-01-01

The ability of sulfate-reducing bacteria to produce hydrogen sulfide and the high affinity of sulfide to react with divalent metallic cations represent an excellent option to remove heavy metals from wastewater. Different parameters have been proposed to control the hydrogen sulfide production by anaerobic bacteria, such as the organic and sulfate loading rates and the feed COD/SO 4 2- ratio. This work relates the feed COD/SO 4 2- ratio with the hydrogen sulfide production and dissolved lead precipitation, using ethanol as carbon and energy source in an up-flow anaerobic sludge blanket reactor. A maximum dissolved sulfide concentration of 470 ± 7 mg S/L was obtained at a feed COD/SO 4 2- ratio of 2.5, with sulfate and ethanol conversions of approximately 94 and 87%, respectively. The lowest dissolved sulfide concentration (145 ± 10 mg S/L) was observed with a feed COD/SO 4 2- ratio of 0.67. Substantial amounts of acetate (510-1730 mg/L) were produced and accumulated in the bioreactor from ethanol oxidation. Although only incomplete oxidation of ethanol to acetate was observed, the consortium was able to remove 99% of the dissolved lead (200 mg/L) with a feed COD/SO 4 2- ratio of 1.5. It was found that the feed COD/SO 4 2- ratio could be an adequate parameter to control the hydrogen sulfide production and the consequent precipitation of dissolved lead

Compounds of divalent thulium, neodymium, and dysprosium

International Nuclear Information System (INIS)

Bochkarev, M.N.; Fedushkin, I.L.; Trifonov, A.A.; Fagin, A.A.; Kirillov, E.N.

1998-01-01

Full text: Judging on the Ln(II)/Ln(III) potentials Tm, Nd, and Dy are the first candidates after Sm, Eu, and Yb for the preparation of Ln(II) compounds. The first molecular Tm(II) derivatives, TmI 2 (DME) 3 (I), has been obtained recently by the reduction of TmI 3 with thulium metal in DME (1,2-dimethoxyethane). The tetrahydrofuran (THF) analogue, TmI 2 (THF) 5 , was synthesized similarly. In the case of TmBI 3 and TmCl 3 the same reaction does not occur. The compound I is inert toward naphthalene, anthracene, phenylacetylene, CpH, (Me 3 Si) 2 NH, 2,4,6-t-Bu 3 C 6 H 2 OH, Cp 2 V, Cp 2 Fe, or Cp 3 Er. The reactions of I with PhOH, Ph 3 COH, 3,6-t-Bu 2 C 6 H 2 (OH) 2 -1,2 (Cat), and calixarene (Cal) produce, Ph 3 COTmI 2 (DME) 2 , (Cat)TmI(DME) 2 , and (Cal)TmI, correspondingly. The attempts to use I for preparation of the other Tm(II) complexes failed. In all cases (reactions with C 10 H 8 Li, CpK, [1,3-(Me 3 Si) 2 C 5 H 3 ]MgCl, and [Cp'-SiMe 2 -Ind']K 2 ) the Tm(III) derivatives (respectively, (C 10 H 8 Tm) 2 C 10 H 8 , Cp 3 Tm, [1,3-(Me 3 Si) 2 C 5 H 3 ] 2 TmCl, and Cp'-SiMe 2 -Ind')TmI) were obtained. The new stable Tm(II) complex, PhOTmI(DME) 2 (II), has been synthesized by the reduction of I with potassium metal in DME. The product was isolated as the green crystals with μ eff 4.6 BM. Unlike TmI 3 , NdI 3 and DyI 3 can not be reduced by metallic neodymium, dysprosium or sodium in DME or THF. Re-investigation of the product formed in the reaction of NdCl 3 with a lack of Li and naphthalene which was claimed before as NdCl 2 (THF) 2 has shown that this is a mixture of Nd(III) naphthalene complexes of the type [(NdCl 2 (THF) 2 ]nC 10 H 8 (n = 4- 7) (III). Nevertheless the product may be used instead of NdCl 2 for the preparation of RNdCl 2 type complexes. The reactions of III with t-BuNCH=CHNBu-t (DAD), PhCH=CHCH=CHPh (DBD), and PhCH=CHPh afford (DAD)NdCl 2 (THF) 2 , (DBD)[NdCl 2 (THF) 2 ] 2 , and (PhCHCHPh)[NdCl 2 ] 2 (THF) 3 , respectively. The iodides of Nd

Synthesis of Copper Sulfide Nanoparticles Using Biogenic H2S Produced by a Low-pH Sulfidogenic Bioreactor

Directory of Open Access Journals (Sweden)

Camila Colipai

2018-01-01

Full Text Available The application of acidophilic sulfate-reducing bacteria (SRB for the treatment of acidic mine water has been recently developed to integrate mine water remediation and selective biomineralization. The use of biogenic hydrogen sulfide (H2S produced from the dissimilatory reduction of sulfate to fabricate valuable products such as metallic sulfide nanoparticles has potential applications in green chemistry. Here we report on the operation of a low-pH sulfidogenic bioreactor, inoculated with an anaerobic sediment obtained from an acid river in northern Chile, to recover copper via the production of copper sulfide nanoparticles using biogenic H2S. The laboratory-scale system was operated as a continuous flow mode for up to 100 days and the bioreactor pH was maintained by the automatic addition of a pH 2.2 influent liquor to compensate for protons consumed by biosulfidogenesis. The “clean” copper sulfide nanoparticles, produced in a two-step process using bacterially generated sulfide, were examined using transmission electron microscopy, dynamic light scattering, energy dispersive (X-ray spectroscopy and UV-Vis spectroscopy. The results demonstrated a uniform nanoparticle size distribution with an average diameter of less than 50 nm. Overall, we demonstrated the production of biogenic H2S using a system designed for the treatment of acid mine water that holds potential for large-scale abiotic synthesis of copper sulfide nanoparticles.

Effect of Ni on the characteristics and hydrogenation activity of sulfide Mo/{gamma}-Al{sub 2}O{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Schachtl, E.; Wuttke, E.; Gutierrez, O.Y.; Lercher, J.A. [Technische Univ. Muenchen, Garching (Germany). Dept. of Chemistry and Catalysis Research Center

2012-07-01

The hydrogenation of phenanthrene was explored on sulfide Mo/{gamma}-Al{sub 2}O{sub 3} catalysts promoted with increasing concentrations of Ni. The characterization of the materials was done by N{sub 2}-physisorption, X-ray diffraction, transmission electron microscopy, temperature programmed sulfidation and NO adsorption experiments. Increasing loading of Ni improves the dispersion of MoS{sub 2} species; however, at Ni/(Mo+Ni) molar ratio higher than 0.5, segregation of Ni-sulfides is observed. The presence of Ni also facilitates the sulfidation of oxidic catalyst precursors by lowering the reduction temperature of Mo species. In the sulfide catalysts, Ni changes the structure of MoS{sub 2} leading to shorter slabs with higher stacking degree than on Mo/{gamma}-Al{sub 2}O{sub 3}, and increases the concentration of coordinatively unsaturated sites. The kinetic results (increased hydrogenation rate and changed reaction network in the presence of Ni) suggest that a highly active kind of active site is created by Ni promotion. (orig.)

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...

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) EFFLUENT GUIDELINES AND STANDARDS LEATHER TANNING AND FINISHING POINT SOURCE CATEGORY General Provisions...

Particle Surface Hydrophobicity and the Dechlorination of Chloro-Compounds by Iron Sulfides

Energy Technology Data Exchange (ETDEWEB)

Park, Sang-Won, E-mail: spark3@uncc.edu; Kim, Sung-Kuk; Kim, Jeong-Bae; Choi, Sung-Woo [Keimyung University, Department of Environmental Science and Engineering (Korea, Republic of); Inyang, Hilary I. [University of North Carolina at Charlotte, Global Institute for Energy and Environmental Systems (United States); Tokunaga, Shuzo [National Institute of Advanced Industrial Science and Technology (Japan)

2006-02-15

Halogenated aliphatic compounds (HACs) can be reduced by iron sulfides in aqueous systems. Generally, the thermodynamics and kinetics of dehalogenation reactions are controlled by the mineralogical and particle surface characteristics of the iron sulfide, the composition of the HAC and reaction conditions such as component concentrations, pH and Eh. In this theoretical and experimental investigation of CCl{sub 4} and C{sub 2}Cl{sub 6} reduction by FeS and FeS{sub 2}, the roles of hydrophobic and hydrophilic sites on the iron sulfides were analyzed. Experimental data obtained through zeta potential measurements, were used along with the Gouy-Chapman model and the simple two-layer surface complexation model to relate iron sulfide surface hydroxyl densities to the degree of HAC dehalogenation. The surface hydroxyl site densities of FeS and FeS{sub 2} were found to be 0.11 sites/nm{sup 2} and 0.21 sites/nm{sup 2}, respectively. During the dehalogenation reaction process, CCl{sub 4} was found to decrease to its first intermediate product CHCl{sub 3} within the first 20 hours followed by a slower process of conversion to CH{sub 2}Cl{sub 2}. The results also show that FeS is less hydrated (more hydrophobic) than FeS{sub 2}. For CCl{sub 4} and C{sub 2}Cl{sub 6}, FeS is a better dehalogenator than FeS{sub 2}. These results imply that particle surface hydrophobicity is a critical factor in surface-mediated dehalogenation of chlorinated compounds.

Novel Mesoporous Flowerlike Iron Sulfide Hierarchitectures: Facile Synthesis and Fast Lithium Storage Capability

Directory of Open Access Journals (Sweden)

Quanning Ma

2017-12-01

Full Text Available The 3D flowerlike iron sulfide (F-FeS is successfully synthesized via a facile one-step sulfurization process, and the electrochemical properties as anode materials for lithium ion batteries (LIBs are investigated. Compared with bulk iron sulfide, we find that the unique structural features, overall flowerlike structure, composed of several dozen nanopetals and numerous small size iron sulfide particles embedded within the fine nanopetals, and hierarchical pore structure features provide signification improvements in lithium storage performance, with a high-rate discharge capacity of 779.0 mAh g−1 at a rate of 5 A g−1, due to effectively alleviating the volume expansion during the lithiation/delithiation process, and shorting the diffusion length of both lithium ion and electron. Especially, an excellent cycling stability are achieved, a high discharge capacity of 890 mAh g−1 retained at a rate of 1.0 A g−1, suggesting its promising applications in lithium ion batteries (LIBs.

Sulfidation treatment of molten incineration fly ashes with Na2S for zinc, lead and copper resource recovery.

Science.gov (United States)

Kuchar, D; Fukuta, T; Onyango, M S; Matsuda, H

2007-04-01

The present study focuses on the conversion of heavy metals involved in molten incineration fly ashes to metal sulfides which could be thereafter separated by flotation. The sulfidation treatment was carried out for five molten incineration fly ashes (Fly ash-A to Fly ash-E) by contacting each fly ash with Na(2)S solution for a period of 10 min to 6h. The initial molar ratio of S(2-) to Me(2+) was adjusted to 1.20. The conversion of heavy metals to metal sulfides was evaluated by measuring the S(2-) residual concentrations using an ion selective electrode. The formation of metal sulfides was studied by XRD and SEM-EDS analyses. In the case of Fly ash-A to Fly ash-D, more than 79% of heavy metals of zinc, lead and copper was converted to metal sulfides within the contacting period of 0.5h owing to a fast conversion of metal chlorides to metal sulfides. By contrast, the conversion of about 35% was achieved for Fly ash-E within the same contacting period, which was attributed to a high content of metal oxides. Further, the S(2-) to Me(2+) molar ratio was reduced to 1.00 to minimize Na(2)S consumption and the conversions obtained within the contacting period of 0.5h varied from 76% for Fly ash-D to 91% for Fly ash-C. Finally, soluble salts such as NaCl and KCl were removed during the sulfidation treatment, which brought about a significant enrichment in metals content by a factor varying from 1.5 for Fly ash-D to 4.9 for Fly ash-A.

Determination of sulfur isotopic composition for the study of iron sulfides origin, biotic or abiotic, in anoxic corrosion

International Nuclear Information System (INIS)

Grousset, Sophie

2016-01-01

The first goal of this project was to develop a methodology based on the study of the sulfur isotopic composition enabling the determination of iron sulfides origin, biotic or abiotic, within the corrosion products layers (CPL). Then, the aim was to apply this methodology to real corrosion systems in order to determine the mechanisms of iron sulfides formation. Sulfur isotopic analyses methodologies, adapted to micrometric iron sulfides layers observed in real corrosion systems, were developed in nanoSIMS and ToF-SIMS. The study of iron sulfides formed in anoxic carbonated medium with or without sulphate-reducing bacteria validated the use of these methods for the determination of iron sulfides origin. The application of these methods coupled with the precise characterization of irons sulfides formed in the real corrosion systems show two kind of corrosion pattern. In pattern 1, the iron sulfides are localized in the external part of the CPL. They result from the Fe 2+ migration from the metal surface to areas rich in biotic S 2- . In this pattern, corrosion rates are lower than 20 μm/year for laboratory systems, and lower than 5 μm/year for archaeological objects. In pattern 2, the large presence of conductive phases in the CPL results in the delocalization of electrons, and so a disequilibrium of the charges at the metal's surface. That leads to the migration of biotic S 2- in the CPL till the metal where they precipitate in iron sulphides. This pattern shows high corrosion rates (∼100 μm/an) that might be resulting from the accumulation of bio-corrosion and chloride corrosion mechanisms. (author) [fr

Effect of growth conditions on microbial activity and iron-sulfide production by Desulfovibrio vulgaris

International Nuclear Information System (INIS)

Zhou, Chen; Vannela, Raveender; Hayes, Kim F.; Rittmann, Bruce E.

2014-01-01

Highlights: • Extended incubation time to 16 days allowed significant FeS crystallization. • A weakly acidic pH greatly enhanced particle growth of mackinawite. • Microbial metabolism of different donors systematically altered the ambient pH. • Greater sulfide accumulation stimulated mackinawite transformation to greigite. - Abstract: Sulfate-reducing bacteria (SRB) can produce iron sulfide (FeS) solids with mineralogical characteristics that may be beneficial for a variety of biogeochemical applications, such as long-term immobilization of uranium. In this study, the growth and metabolism of Desulfovibrio vulgaris, one of the best-studied SRB species, were comprehensively monitored in batch studies, and the biogenic FeS solids were characterized by X-ray diffraction. Controlling the pH by varying the initial pH, the iron-to-sulfate ratio, or the electron donor – affected the growth of D. vulgaris and strongly influenced the formation and growth of FeS solids. In particular, lower pH (from initial conditions or a decrease caused by less sulfate reduction, FeS precipitation, or using pyruvate as the electron donor) produced larger-sized mackinawite (Fe 1+x S). Greater accumulation of free sulfide, from more sulfate reduction by D. vulgaris, also led to larger-sized mackinawite and particularly stimulated mackinawite transformation to greigite (Fe 3 S 4 ) when the free sulfide concentration was 29.3 mM. Furthermore, sufficient free Fe 2+ led to the additional formation of vivianite [Fe 3 (PO 4 ) 2 ·8(H 2 O)]. Thus, microbially relevant conditions (initial pH, choice of electron donor, and excess or deficiency of sulfide) are tools to generate biogenic FeS solids of different characteristics

Influence of sulfidation treatment on the structure and tribological properties of nitrogen-doped diamond-like carbon films

International Nuclear Information System (INIS)

Zeng Qunfeng; Dong Guangneng; Xie Youbai

2008-01-01

The nitrogen-doped diamond-like carbon (DLC) films were deposited on high speed steel (HSS) substrates in the direct current unbalanced magnetron sputtering system. Sulphurized layer was formed on the surface of DLC films by means of liquid sulfidation in the intermixture of urea and thiourea solution in order to improve the tribological properties of DLC films. The influence of sulfidation treatment on the structure and tribological properties of DLC films was investigated in this work. The structure and wear surface morphology of DLC films were analyzed by Raman spectroscopy, XPS and SEM, respectively. It reveals that the treated films are smooth and uniform; and sulfur atoms are bonded chemically. The treated films have broader distribution of Raman spectra in the range of 1000-1800 cm -1 and higher I D /I G ratio than the untreated films as a result of the appearance of the crystalline graphite structure after the sulfidation treatment. It is showed that the sp 2 relative content increase in the treated films from the XPS measurement. The Raman results are consistent with the XPS results. The tribological properties of DLC films were investigated using a ball-on-disk rotating friction and wear tester under dry friction conditions. It is found that the sulfidation concentration plays an important part in the tribological properties of the treated DLC films. The results showed the treated films with low sulfidation concentration have a lower friction coefficient (0.1) than the treated films with high sulfidation concentration (0.26) and the untreated films (0.27) under the same friction testing conditions, which can be attributed to both the presence of sulfur-containing materials and the forming of the mechanical alloyed layer on the wear surface. Adding the dry nitrogen to the sliding surface in the testing system helps the friction coefficient of the treated films with low sulfidation concentration to decrease to 0.04 further in this work. On the basis of the

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

Isotopic data from proterozoic sediment-hosted sulfide deposits of Brazil: Implications for their metallogenic evolution and for mineral exploration

International Nuclear Information System (INIS)

Misi, Aroldo; Coelho, Carlos E.S.; Franca Rocha, Washington J.S.; Gomez, Adriana S.R.; Cunha, Iona A.; Iyer, Sundaram S.; Tassinari, Colombo C.G.; Kyle, J. Richard

1998-01-01

Geological, petrographic, fluid inclusions studies and isotopic data of seven Proterozoic sediment-hosted Pb-Zn-Ag sulfide deposits of Brazil, permit the estimation of the age of the hosting sequence and the mineralization, the nature of the sulfur and metal sources, the temperature range of sulfide formation and the environment of deposition of the mineral deposits. The studies suggest that they were formed during periods of extensional tectonics: Growth faults or reactivated basement faults were responsible for localized circulation of metal-bearing fluids within the sedimentary sequences. In most cases, sulfides were formed by the reduction of sedimentary sulfates. Linear structures are important controls for sulfide concentration in these Proterozoic basins. (author)

Determination of kinetics and stoichiometry of chemical sulfide oxidation in wastewater of sewer networks

DEFF Research Database (Denmark)

Nielsen, Asbjørn Haaning; 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...... 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...... on continuous measurement of the reactants allowing the kinetics to be determined at varying reactant concentrations during the course of the experiment. The kinetics determined was simulated by a rate equation. The precision of the method was assessed in terms of the standard deviation of the kinetic...

Release of hydrogen sulfide in a sewer system under intermittent flow conditions

DEFF Research Database (Denmark)

Matias, Natércia; Matos, Rita Ventura; Ferreira, Filipa

2017-01-01

The presence and fate of hydrogen sulfide in wastewater systems were studied in two stretches of an intercepting sewer system located in a coastal village, in Portugal. A range of hydraulic parameters were obtained and liquid and gas phase measurements were carried out, both continuously and thro......The presence and fate of hydrogen sulfide in wastewater systems were studied in two stretches of an intercepting sewer system located in a coastal village, in Portugal. A range of hydraulic parameters were obtained and liquid and gas phase measurements were carried out, both continuously...... authors’ publications addressing relatively small pipes and moderate water flows....

Silver sulfide nanoparticle assembly obtained by reacting an assembled silver nanoparticle template with hydrogen sulfide gas.

Science.gov (United States)

Chen, Rui; Nuhfer, Noel T; Moussa, Laura; Morris, Hannah R; Whitmore, Paul M

2008-11-12

A fast, simple procedure is described for obtaining an assembly of silver sulfide nanoparticles (Ag(2)S NPs) on a glass substrate through reaction of a template of an assembled layer of silver nanoparticles (Ag NPs) with hydrogen sulfide (H(2)S) gas. The Ag NP template was prepared by assembling a monolayer of spherical Ag NPs (mean diameter of 7.4 nm) on a polyethylenimine-treated glass substrate. Exposure to pure H(2)S for 10 min converted the Ag NPs of the template to Ag(2)S NPs. The resulting Ag(2)S NP assembly, which retains the template nanostructure and particle distribution, was characterized by optical absorption spectroscopy, atomic force microscopy, transmission electron microscopy (TEM), scanning high resolution TEM, energy dispersive x-ray spectroscopy and x-ray photoelectron spectroscopy. The Ag(2)S NPs have a crystal structure of monoclinic acanthite, and while they retained the spherical shape of the original Ag NPs, their mean particle size increased to 8.4 nm due to changes to the crystal structure when the Ag NPs are converted into Ag(2)S NPs. The measured optical absorption edge of the Ag(2)S NP assembly indicated an indirect interband transition with a band gap energy of 1.71 eV. The Ag(2)S NP assembly absorbed light with wavelengths below 725 nm, and the absorbance increased monotonically toward the UV region.

Enrichment and cultivation of a sulfide-oxidizing bacteria consortium for its deploying in full-scale biogas desulfurization

International Nuclear Information System (INIS)

González Sánchez, Armando; Flores Márquez, Trinidad Eliseo; Revah, Sergio; Morgan Sagastume, Juan Manuel

2014-01-01

Operational experiences and strategies to get suitable chemolithoautotrophic sulfide-oxidizing biomass from activated sludge wastewater treatment plant for its deploying in a full-scale biogas desulfurization plant are described. An economic nutrient source was applied to foster microbial selection and rapid growth. Respirometry was implemented on full-scale installations to monitor the ability of the specialized bacteria consortium to oxidize reduced sulfur i.e. H 2 S. During the deployment in the full-scale desulfurization reactor, intermittent sulfide feed from biogas scrubbing was performed to accelerate the startup the desulfurization process. - Highlights: • A simple method for reaching high amounts of specialized sulfide-oxidizing bacterial consortium from activated sludge was developed. • The full-scale desulfurization process can be continuously monitored by respirometry allowing fast decision making if problems arise. • The dissolved sulfide concentration was estimated with an empirical correlation between measurements of ORP, dissolved oxygen and pH

Facile Synthesis of Flower-Like Copper-Cobalt Sulfide as Binder-Free Faradaic Electrodes for Supercapacitors with Improved Electrochemical Properties

Science.gov (United States)

Wang, Tianlei; Liu, Meitang; Ma, Hongwen

2017-01-01

Supercapacitors have been one of the highest potential candidates for energy storage because of their significant advantages beyond rechargeable batteries in terms of large power density, short recharging time, and long cycle lifespan. In this work, Cu–Co sulfides with uniform flower-like structure have been successfully obtained via a traditional two-step hydrothermal method. The as-fabricated Cu–Co sulfide vulcanized from precursor (P–Cu–Co sulfide) is able to deliver superior specific capacitance of 592 F g−1 at 1 A g−1 and 518 F g−1 at 10 A g−1 which are surprisingly about 1.44 times and 2.39 times higher than those of Cu–Co oxide electrode, respectively. At the same time, excellent cycling stability of P–Cu–Co sulfide is indicated by 90.4% capacitance retention at high current density of 10 A g−1 after 3000 cycles. Because of the introduction of sulfur during the vulcanization process, these new developed sulfides can get more flexible structure and larger reaction surface area, and will own richer redox reaction sites between the interfaces of active material/electrolyte. The uniform flower-like P–Cu–Co sulfide electrode materials will have more potential alternatives for oxides electrode materials in the future. PMID:28590417

Facile Synthesis of Flower-Like Copper-Cobalt Sulfide as Binder-Free Faradaic Electrodes for Supercapacitors with Improved Electrochemical Properties

Directory of Open Access Journals (Sweden)

Tianlei Wang

2017-06-01

Full Text Available Supercapacitors have been one of the highest potential candidates for energy storage because of their significant advantages beyond rechargeable batteries in terms of large power density, short recharging time, and long cycle lifespan. In this work, Cu–Co sulfides with uniform flower-like structure have been successfully obtained via a traditional two-step hydrothermal method. The as-fabricated Cu–Co sulfide vulcanized from precursor (P–Cu–Co sulfide is able to deliver superior specific capacitance of 592 F g−1 at 1 A g−1 and 518 F g−1 at 10 A g−1 which are surprisingly about 1.44 times and 2.39 times higher than those of Cu–Co oxide electrode, respectively. At the same time, excellent cycling stability of P–Cu–Co sulfide is indicated by 90.4% capacitance retention at high current density of 10 A g−1 after 3000 cycles. Because of the introduction of sulfur during the vulcanization process, these new developed sulfides can get more flexible structure and larger reaction surface area, and will own richer redox reaction sites between the interfaces of active material/electrolyte. The uniform flower-like P–Cu–Co sulfide electrode materials will have more potential alternatives for oxides electrode materials in the future.

Facile Synthesis of Flower-Like Copper-Cobalt Sulfide as Binder-Free Faradaic Electrodes for Supercapacitors with Improved Electrochemical Properties.

Science.gov (United States)

Wang, Tianlei; Liu, Meitang; Ma, Hongwen

2017-06-07

Supercapacitors have been one of the highest potential candidates for energy storage because of their significant advantages beyond rechargeable batteries in terms of large power density, short recharging time, and long cycle lifespan. In this work, Cu-Co sulfides with uniform flower-like structure have been successfully obtained via a traditional two-step hydrothermal method. The as-fabricated Cu-Co sulfide vulcanized from precursor (P-Cu-Co sulfide) is able to deliver superior specific capacitance of 592 F g -1 at 1 A g -1 and 518 F g -1 at 10 A g -1 which are surprisingly about 1.44 times and 2.39 times higher than those of Cu-Co oxide electrode, respectively. At the same time, excellent cycling stability of P-Cu-Co sulfide is indicated by 90.4% capacitance retention at high current density of 10 A g -1 after 3000 cycles. Because of the introduction of sulfur during the vulcanization process, these new developed sulfides can get more flexible structure and larger reaction surface area, and will own richer redox reaction sites between the interfaces of active material/electrolyte. The uniform flower-like P-Cu-Co sulfide electrode materials will have more potential alternatives for oxides electrode materials in the future.

Removal of metals from lead-zinc mine tailings using bioleaching and followed by sulfide precipitation.

Science.gov (United States)

Ye, Maoyou; Li, Guojian; Yan, Pingfang; Ren, Jie; Zheng, Li; Han, Dajian; Sun, Shuiyu; Huang, Shaosong; Zhong, Yujian

2017-10-01

Mine tailings often contain significant amounts of metals and sulfide, many traditional operations used to minerals was not as good as those currently available. This study investigated metals removal from lead-zinc mine tailings using bioleaching and followed by sulfide precipitation. Metals were dissolved from the tailings by the bacteria in a bioleaching reactor. During a 10% pulp density bioleaching experiment, approximately 0.82% Pb, 97.38% Zn, and 71.37% Fe were extracted after 50 days. With the pulp density of 10% and 20%, the dissolution of metals followed shrinking core kinetic model. Metals (Pb, Zn, and Fe) present in the pregnant bioleaching leachate. Metals were next precipitated as a sulfide phase using sodium sulfide (Na 2 S). Metal precipitations were selectively and quantitatively produced from the bioleaching leachate by adding Na 2 S. More than 99% of the zinc and 75% of the iron was precipitated using 25 g/L Na 2 S in the bioleaching leachate. The results in the study were to provide useful information for recovering or removing metals from lead-zinc mine tailings. Copyright © 2017 Elsevier Ltd. All rights reserved.

Nutrient Availability Alters the Effect of Autophagy on Sulindac Sulfide-Induced Colon Cancer Cell Apoptosis

Directory of Open Access Journals (Sweden)

Shiun-Kwei Chiou

2012-01-01

Full Text Available Autophagy is a catabolic process by which a cell degrades its intracellular materials to replenish itself. Induction of autophagy under various cellular stress stimuli can lead to either cell survival or cell death via apoptotic and/or autophagic (nonapoptotic pathways. The NSAID sulindac sulfide induces apoptosis in colon cancer cells. Here, we show that inhibition of autophagy under serum-deprived conditions resulted in significant reductions of sulindac sulfide-induced apoptosis in HT-29 colon cancer cells. In contrast, inhibition of autophagy under conditions where serum is available significantly increased sulindac sulfide-induced apoptosis in HT-29 cells. We previously showed that the apoptosis inhibitor, survivin, plays a role in regulating NSAID-induced apoptosis and autophagic cell death. Here, we show that survivin protein half-life is increased in the presence of autophagy inhibitors under serum-deprived conditions, but not under conditions when serum is available. Thus, the increased levels of survivin may be a factor contributing to inhibition of sulindac sulfide-induced apoptosis under serum-deprived conditions. These results suggest that whether a cell lives or dies due to autophagy induction depends on the balance of factors that regulate both autophagic and apoptotic processes.

Tracking the transformation and transport of arsenic sulfide pigments in paints: synchrotron-based X-ray micro-analyses

NARCIS (Netherlands)

Keune, K.; Mass, J.; Meirer, F.; Pottasch, C.; van Loon, A.; Hull, A.; Church, J.; Pouyet, E.; Cotte, M.; Mehta, A.

2015-01-01

Realgar and orpiment, arsenic sulfide pigments used in historic paints, degrade under the influence of light, resulting in transparent, whitish, friable and/or crumbling paints. So far, para-realgar and arsenic trioxide have been identified as the main oxidation products of arsenic sulfide pigments.

Tracking the transformation and transport of arsenic sulfide pigments in paints : synchrotron-based X-ray micro-analyses

NARCIS (Netherlands)

Keune, Katrien; Mass, Jennifer; Meirer, Florian; Pottasch, Carol; van Loon, Annelies; Hull, Alyssa; Church, Jonathan; Pouyet, Emeline; Cotte, Marine; Mehta, Apurva

2015-01-01

Realgar and orpiment, arsenic sulfide pigments used in historic paints, degrade under the influence of light, resulting in transparent, whitish, friable and/or crumbling paints. So far, para-realgar and arsenic trioxide have been identified as the main oxidation products of arsenic sulfide pigments.

Evaluation of feed COD/sulfate ratio as a control criterion for the biological hydrogen sulfide production and lead precipitation

Energy Technology Data Exchange (ETDEWEB)

Velasco, Antonio [Direccion General del Centro Nacional de Investigacion y Capacitacion Ambiental-Instituto Nacional de Ecologia, Av. San Rafael Atlixco 186, Col. Vicentina. Iztapalapa, Mexico 09340, D.F. (Mexico)], E-mail: jvelasco@ine.gob.mx; Ramirez, Martha [Direccion General del Centro Nacional de Investigacion y Capacitacion Ambiental-Instituto Nacional de Ecologia, Av. San Rafael Atlixco 186, Col. Vicentina. Iztapalapa, Mexico 09340, D.F. (Mexico); Volke-Sepulveda, Tania [Departamento de Biotecnologia, UAM-Cuajimalpa, San Rafael Atlixco 186, Col. Vicentina. Iztapalapa, Mexico 09340, D.F. (Mexico); Gonzalez-Sanchez, Armando [Departamento de Ingenieria de Procesos, Universidad Autonoma Metropolitana-Iztapalapa, UAM-Cuajimalpa, San Rafael Atlixco 186, Col. Vicentina. Iztapalapa, Mexico 09340, D.F. (Mexico); Revah, Sergio [Departamento de Procesos y Tecnologia, UAM-Cuajimalpa, San Rafael Atlixco 186, Col. Vicentina. Iztapalapa, Mexico 09340, D.F. (Mexico)

2008-03-01

The ability of sulfate-reducing bacteria to produce hydrogen sulfide and the high affinity of sulfide to react with divalent metallic cations represent an excellent option to remove heavy metals from wastewater. Different parameters have been proposed to control the hydrogen sulfide production by anaerobic bacteria, such as the organic and sulfate loading rates and the feed COD/SO{sub 4}{sup 2-} ratio. This work relates the feed COD/SO{sub 4}{sup 2-} ratio with the hydrogen sulfide production and dissolved lead precipitation, using ethanol as carbon and energy source in an up-flow anaerobic sludge blanket reactor. A maximum dissolved sulfide concentration of 470 {+-} 7 mg S/L was obtained at a feed COD/SO{sub 4}{sup 2-} ratio of 2.5, with sulfate and ethanol conversions of approximately 94 and 87%, respectively. The lowest dissolved sulfide concentration (145 {+-} 10 mg S/L) was observed with a feed COD/SO{sub 4}{sup 2-} ratio of 0.67. Substantial amounts of acetate (510-1730 mg/L) were produced and accumulated in the bioreactor from ethanol oxidation. Although only incomplete oxidation of ethanol to acetate was observed, the consortium was able to remove 99% of the dissolved lead (200 mg/L) with a feed COD/SO{sub 4}{sup 2-} ratio of 1.5. It was found that the feed COD/SO{sub 4}{sup 2-} ratio could be an adequate parameter to control the hydrogen sulfide production and the consequent precipitation of dissolved lead.

Invisible and microscopic gold in pyrite: Methods and new data for massive sulfide ores of the Urals

Science.gov (United States)

Vikentyev, I. V.

2015-07-01

Au speciation in sulfides (including "invisible" Au), which mostly controls the loss of Au during ore dressing, is discussed. Modern methods of analysis of Au speciation, with discussion of limitations by locality and sensitivity, are reviewed. The results of sulfide investigation by the methods of scanning and transmission electron microscopy, mass spectrometric analysis with laser ablation (LA-ICP-MS), the thermochemical method (study of ionic Au speciation), and automated "quantitative mineralogy," are demonstrated for weakly metamorphosed VHMS deposits of the Urals (Galkinsk and Uchaly). Significant content of Au is scattered in sulfides, such as pyrite, chalcopyrite, and sphalerite, with quantitative predomination of pyrite. The portion of such "invisible" gold ranges from flakes) with a monocrystal diffraction pattern of some particles and a ring diffraction pattern of other particles was registered in the ores of these deposits by the methods of transmission electron microscopy. The low degree (or absence) of metamorphic recrystallization results in (1) predomination of thin intergrowths of sulfides, which is the main reason for the bad concentration of ores (especially for the Galkinsk deposit) and (2) the high portion of "invisible" gold in the massive sulfide ores, which explains the low yield of Au in copper and zinc concentrates, since it is lost in tailings with predominating pyrite.

Recent progress in sulfide-based solid electrolytes for Li-ion batteries

Energy Technology Data Exchange (ETDEWEB)

Liu, D., E-mail: liu.dongqiang@ireq.ca; Zhu, W.; Feng, Z.; Guerfi, A.; Vijh, A.; Zaghib, K.

2016-11-15

Graphical abstract: Li{sub 2}S-GeS{sub 2}-P{sub 2}S{sub 5} ternary diagram showing various sulphide compounds as solid electrolytes for Li-ion batteries. - Highlights: • Recent progress of sulfide-based solid electrolytes is described from point of view of structure. • Thio-LISICON type electrolytes exhibited high ionic conductivity due to their bcc sublattice and unique Li{sup +} diffusion pathway. • “Mixed-anion effect” is also an effective way to modify the energy landscape as well as the ionic conductivity. - Abstract: Sulfide-based ionic conductors are one of most attractive solid electrolyte candidates for all-solid-state batteries. In this review, recent progress of sulfide-based solid electrolytes is described from point of view of structure. In particular, lithium thio-phosphates such as Li{sub 7}P{sub 3}S{sub 11}, Li{sub 10}GeP{sub 2}S{sub 12} and Li{sub 11}Si{sub 2}PS{sub 12} etc. exhibit extremely high ionic conductivity of over 10{sup −2} S cm{sup −1} at room temperature, even higher than those of commercial organic carbonate electrolytes. The relationship between structure and unprecedented high ionic conductivity is delineated; some potential drawbacks of these electrolytes are also outlined.

A batch assay to measure microbial hydrogen sulfide production from sulfur-containing solid wastes

Energy Technology Data Exchange (ETDEWEB)

Sun, Mei, E-mail: msun8@uncc.edu [Department of Civil, Construction, and Environmental Engineering, North Carolina State University, Campus Box 7908, Raleigh, NC (United States); Sun, Wenjie, E-mail: wsun@smu.edu [Department of Civil, Construction, and Environmental Engineering, North Carolina State University, Campus Box 7908, Raleigh, NC (United States); Department of Civil and Environmental Engineering, Southern Methodist University, PO Box 750340, Dallas, TX (United States); Barlaz, Morton A., E-mail: barlaz@ncsu.edu [Department of Civil, Construction, and Environmental Engineering, North Carolina State University, Campus Box 7908, Raleigh, NC (United States)

2016-05-01

Large volumes of sulfur-containing wastes enter municipal solid waste landfills each year. Under the anaerobic conditions that prevail in landfills, oxidized forms of sulfur, primarily sulfate, are converted to sulfide. Hydrogen sulfide (H{sub 2}S) is corrosive to landfill gas collection and treatment systems, and its presence in landfill gas often necessitates the installation of expensive removal systems. For landfill operators to understand the cost of managing sulfur-containing wastes, an estimate of the H{sub 2}S production potential is needed. The objective of this study was to develop and demonstrate a biochemical sulfide potential (BSP) test to measure the amount of H{sub 2}S produced by different types of sulfur-containing wastes in a relatively fast (30 days) and inexpensive (125 mL serum bottles) batch assay. This study confirmed the toxic effect of H{sub 2}S on both sulfate reduction and methane production in batch systems, and demonstrated that removing accumulated H{sub 2}S by base adsorption was effective for mitigating inhibition. H{sub 2}S production potentials of coal combustion fly ash, flue gas desulfurization residual, municipal solid waste combustion ash, and construction and demolition waste were determined in BSP assays. After 30 days of incubation, most of the sulfate in the wastes was converted to gaseous or aqueous phase sulfide, with BSPs ranging from 0.8 to 58.8 mL H{sub 2}S/g waste, depending on the chemical composition of the samples. Selected samples contained solid phase sulfide which contributed to the measured H{sub 2}S yield. A 60 day incubation in selected samples resulted in 39–86% additional sulfide production. H{sub 2}S production measured in BSP assays was compared with that measured in simulated landfill reactors and that calculated from chemical analyses. H{sub 2}S production in BSP assays and in reactors was lower than the stoichiometric values calculated from chemical composition for all wastes tested, demonstrating

Active hydrothermal and non-active massive sulfide mound investigation using a new multiparameter chemical sensor

Science.gov (United States)

Han, C.; Wu, G.; Qin, H.; Wang, Z.

2012-12-01

Investigation of active hydrothermal mound as well as non-active massive sulfide mound are studied recently. However, there is still lack of in-situ detection method for the non-active massive sulfide mound. Even though Transient ElectroMagnetic (TEM) and Electric Self-potential (SP) methods are good, they both are labour, time and money cost work. We proposed a new multiparameter chemical sensor method to study the seafloor active hydrothermal mound as well as non-active massive sulfide mound. This sensor integrates Eh, S2- ions concentration and pH electrochemical electrodes together, and could found chemical change caused by the active hydrothermal vent, even weak chemical abnormalities by non-active massive sulfide hydrothermal mound which MARP and CTD sometimes cannot detect. In 2012, the 1st Leg of the Chinese 26th cruise, the multiparameter chemical sensor was carried out with the deepsea camera system over the Carlsberg Ridge in Indian Ocean by R/V DAYANGYIHAO. It was shown small Eh and S2- ions concentration abnormal around a site at Northwest Indian ridge. This site was also evidenced by the TV grab. In the 2nd Leg of the same cruise in June, this chemical sensor was carried out with TEM and SP survey system. The chemical abnormalities are matched very well with both TEM and SP survey results. The results show that the multiparameter chemical sensor method not only can detect active hydrothermal mound, but also can find the non-active massive sulfide hydrothermal mound.

Carbon-supported iron and iron-molybdenum sulfide catalysts

International Nuclear Information System (INIS)

Ramselaar, W.L.T.M.

1988-01-01

The main objective was to describe the relations between the characteristics (composition and dispersion) of the actual sulfide phase and the catalytic activity. Attention was also paid to the influence of preparational aspects on these characteristics. The catalysts were characterized using in-situ Moessbauer spectroscopy down to 2.0 K. 254 refs.; 47 figs.; 22 tabs

Estimation of bacterial hydrogen sulfide production in vitro

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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.

Native gold and gold-rich sulfide deposits in a submarine basaltic caldera, Higashi-Aogashima hydrothermal field, Izu-Ogasawara frontal arc, Japan

Science.gov (United States)