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1

A Drude polarizable model for liquid hydrogen sulfide.  

PubMed

A polarizable force field for liquid hydrogen sulfide (H2S) has been developed based on the Drude oscillator model. This force field has been designed to be analogous to the SWM4-NDP water model; the model is rigid with point charges assigned to the H and S atoms and a lone pair on the bisector of ?HSH in the molecular plane. Positions of the lone pair and the charges have been defined such that the model has a static dipole moment of 0.98 D, equal to the experimental value. Polarizability is incorporated by a charged (Drude) particle attached to the S atom through a harmonic potential. Intermolecular nonbonded forces are included by use of a Lennard-Jones potential between S atoms. The model was parametrized to reproduce the density, enthalpy of vaporization, and dielectric constant of pure H2S at 212 K and 1 atm. The calculated density, enthalpy of vaporization, shear viscosity coefficient, and self-diffusion coefficient are in good agreement with experiment over the temperature range 212-298 K along the liquid-vapor coexistence curve of liquid H2S. The radial distribution function calculated from this model is in good agreement with experimental diffraction data and ab initio molecular dynamics simulations. PMID:23566029

Riahi, Saleh; Rowley, Christopher N

2013-05-01

2

Continuous Crystallization of Sulfur Formed by the Liquid-Phase Reaction of Hydrogen Sulfide and Sulfur Dioxide.  

National Technical Information Service (NTIS)

The crystallization of elemental sulfur is a unit operation in a process being developed to remove hydrogen sulfide from industrial gas streams. The sulfur is formed by the irreversible, liquid-phase reaction of hydrogen sulfide (H(sub 2)S) and sulfur dio...

C. A. Stevens S. Lynn

1989-01-01

3

Geothermal hydrogen sulfide removal  

SciTech Connect

UOP Sulfox technology successfully removed 500 ppM hydrogen sulfide from simulated mixed phase geothermal waters. The Sulfox process involves air oxidation of hydrogen sulfide using a fixed catalyst bed. The catalyst activity remained stable throughout the life of the program. The product stream composition was selected by controlling pH; low pH favored elemental sulfur, while high pH favored water soluble sulfate and thiosulfate. Operation with liquid water present assured full catalytic activity. Dissolved salts reduced catalyst activity somewhat. Application of Sulfox technology to geothermal waters resulted in a straightforward process. There were no requirements for auxiliary processes such as a chemical plant. Application of the process to various types of geothermal waters is discussed and plans for a field test pilot plant and a schedule for commercialization are outlined.

Urban, P.

1981-04-01

4

The continuous crystallization of sulfur formed by the liquid-phase reaction of hydrogen sulfide and sulfur dioxide  

Microsoft Academic Search

The crystallization of elemental sulfur is a unit operation in a process being developed to remove hydrogen sulfide from industrial gas streams. The sulfur is formed by the irreversible, liquid-phase reaction of hydrogen sulfide (HâS) and sulfur dioxide (SOâ). Low-temperature sulfur solubility data in triethylene glycol dimethyl ether (Triglyme) and diethylene glycol methyl ether (DGM) were collected. The effects of

C. A. Stevens; S. Lynn

1989-01-01

5

Hydrogen sulfide poisoning  

Microsoft Academic Search

Poisoning by hydrogen sulfide has been recognized as an occupational hazard for at least two centuries. The development of alternative sources of energy in North America may increase the incidence of this medical emergency in the future. Until recently, no specific antidote to sulfide was recognized. We have compared sulfide poisoning to cyanide poisoning and documented recent findings that indicate

Roger P. Smith; Robert E. Gosselin

1979-01-01

6

Geothermal hydrogen sulfide removal  

Microsoft Academic Search

UOP Sulfox technology successfully removed 500 ppM hydrogen sulfide from simulated mixed phase geothermal waters. The Sulfox process involves air oxidation of hydrogen sulfide using a fixed catalyst bed. The catalyst activity remained stable throughout the life of the program. The product stream composition was selected by controlling pH; low pH favored elemental sulfur, while high pH favored water soluble

1981-01-01

7

Suicide with hydrogen sulfide.  

PubMed

This presentation will address the recent rise of suicide deaths resulting from the asphyxiation by hydrogen sulfide (H2S) gas.Hydrogen sulfide poisoning has been an infrequently encountered cause of death in medical examiner practice. Most H2S deaths that have been reported occurred in association with industrial exposure.More recently, H2S has been seen in the commission of suicide, particularly in Japan. Scattered reports of this phenomenon have also appeared in the United States.We have recently observed 2 intentional asphyxial deaths in association with H2S. In both cases, the decedents committed suicide in their automobiles. They generated H2S by combining a sulfide-containing tree spray with toilet bowl cleaner (with an active ingredient of hydrogen chloride acid). Both death scenes prompted hazardous materials team responses because of notes attached to the victims' car windows indicating the presence of toxic gas. Autopsy findings included discoloration of lividity and an accentuation of the gray matter of the brain. Toxicology testing confirmed H2S exposure with the demonstration of high levels of thiosulfate in blood.In summary, suicide with H2S appears to be increasing in the United States. PMID:23574866

Sams, Ralph Newton; Carver, H Wayne; Catanese, Charles; Gilson, Thomas

2013-06-01

8

Solubility of Hydrogen Sulfide in [bmim][PF 6  

Microsoft Academic Search

  New experimental data are presented for the solubility of hydrogen sulfide in the ionic liquid 1-N-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]) at five temperatures in the range (298–403) K at pressures up to 9.6 MPa. The ionic liquid [bmim][PF6] is a good solvent for hydrogen sulfide. At 9 MPa the mole fraction H2S in the liquid is about 0.7. The solubility is a strong function

Fang-Yuan Jou; Alan E. Mather

2007-01-01

9

Endogenous production of hydrogen sulfide in mammals  

Microsoft Academic Search

Summary. Hydrogen sulfide is one of three gases involved in biological functions and synthesized in vivo. Like NO and CO, it seems to act as a neuromodulator: it modulates NMDA glutamate receptor function. CBS seems to be the only source of hydrogen sulfide in the brain, whereas the liver synthesizes hydrogen sulfide via cystathionase. In the heart, the third pathway

P. Kamoun

2004-01-01

10

Gas-liquid interactions of ammonia, sulfur dioxide, hydrogen sulfide, deuterated acetic acid and ethanol on aqueous surfaces  

NASA Astrophysics Data System (ADS)

Heterogeneous gas-liquid interactions play a fundamental role in atmospheric chemistry and are of importance also in biochemical and industrial processes. Here we examine the gas-liquid interactions of several species important in the chemistry of the atmosphere. The experiments are performed using a droplet apparatus in which a stream of well-defined, monodisperse droplets is passed through a low pressure flow tube containing the gas phase species of interest. The uptake of gas species by the droplets is determined by measuring changes in gas density as the droplet area is changed in a step-wise fashion. The experimental results yield information useful in atmospheric modeling and important to the understanding of chemical interactions at the gas-liquid interface. The following studies were performed: (1) Uptake of gas phase ammonia (NH3) by aqueous surfaces was measured as a function of pH (0-13), temperature (263-293K), and gas liquid interaction time (2-15 ms). Uptake measurements yielded values of the mass accommodation and Henry's law coefficients as a function of temperature. (2) Uptake of gas phase sulfur dioxide (SO2) by aqueous surfaces was measured as a function of pH (3-14) and temperature (263-293K). Experimental results yielded the rate coefficient for the SO2 + OH- reaction and mass accommodation coefficient, both as a function of temperature. (3) Uptake of gas phase hydrogen sulfide (H2S) by aqueous surfaces was measured as a function of pH (10-14) and temperature. Studies yielded the rate coefficient for the reaction of H2S with OH- including the activation energy for the reaction. (4) Isotope exchange for deuterated gas-phase acetic acid and ethanol in contact with water (H 2O) droplets was studied using the droplet apparatus. Studies were conducted as a function of pH, droplet temperature and gas liquid interaction time. Experimental results provided a better understanding of the fundamental properties of the gas-liquid interface including the nature of the reactive processes at the gas-liquid interface.

Shi, Quan

1998-11-01

11

Removal of hydrogen sulfide from reducing gases  

Microsoft Academic Search

IGT's method of removing sulfur compounds from hot reducing fuel-gas streams requires no preliminary cooling and subsequent reheating of the gases. A melt of molten lead and a metal sulfide is contacted with the hot reducing gases to remove compounds such as hydrogen sulfide, carbonyl sulfide, and mercaptans. The lead and elemental sulfur are regenerated from the formed lead sulfide

Meissner

1976-01-01

12

Dissociation constants of hydrogen sulfide in concentrated sodium chloride solutions  

SciTech Connect

The first- and second-stage dissociation constants of hydrogen sulfide in various forms were determined experimentally at ionic strength in the range from 0.1 to 5 M at 298, 323, and 348 K. Empirical equations for the dependence of these constants in this region of ionic strengths and temperature on the ionic strength of the solution were obtained; these equations can be used for calculation of equilibria in sulfide solutions of high ionic strength. A gas-liquid constant of hydrogen sulfide, expressed in terms of the solution pH, the equilibrium hydrogen sulfide pressure, and the concentration of sulfide sulfur in solution, i.e., the usual characteristics of industrial sulfide solutions, is proposed.

Yakovlev, V.A.; Poltoratskii, G.M.; Grigor'eva, N.V.

1987-10-20

13

Gas-Liquid Precipitation of Water Dissolved Heavy Metal Ions Using Hydrogen Sulfide Gas  

Microsoft Academic Search

Precipitation of solids promoted by gas-liquid reactions is applied in many industrial processes such as the production of ammonium phosphate, ammonium sulphate, barium carbonate, calcium carbonate, calcium fluoride, ypsum (calcium sulphate), goethite, sodium bicarbonate, strontium carbonate and terephthalic acid. In ddition gas-liquid precipitation can be applied in gas cleaning, heavy metal removal and in biotechnology. Despite the importance of this

Mousa Al-Tarazi

2004-01-01

14

Influence of the interaction between hydrogen sulfide and ionic liquids on solubility: experimental and theoretical investigation.  

PubMed

The solubility of H(2)S in a series of 1-butyl-3-methylimidazolium ([bmim](+)) based ionic liquids (ILs) with different anions, chloride, tetrafluoroborate ([BF(4)](-)), hexafluorophosphate ([PF(6)](-)), triflate ([TfO](-)), and bis(trifluoromethyl)sulfonylimide ([Tf(2)N]-), and in a series of [Tf(2)N] ILs with different cations, i.e., N-alkyl-N'-methylimidazolium, 2-methyl-N-methyl-N'-alkyimidazolium, N-alkylpyridinium, N-butyl-N-methylpyrrolidinium, and N-alkyl-N,N-dimethyl-N-(2-hydroxyethyl)ammonium has been determined using medium-pressure NMR spectroscopy. The observed solubilities are significantly higher than those reported for many other gases in ILs, suggesting the occurrence of specific interactions between H2S and the examined ILs. Quantum chemical calculations have been used to investigate at a molecular level the interaction between H2S and the [bmim](+)-based ILs. PMID:17949033

Pomelli, Christian Silvio; Chiappe, Cinzia; Vidis, Ana; Laurenczy, Gabor; Dyson, Paul J

2007-11-15

15

Keggin heteropolycompounds as catalysts for liquid-phase oxidation of sulfides to sulfoxides\\/sulfones by hydrogen peroxide  

Microsoft Academic Search

H4PMo11VO40, H5PMo10V2O40 and H9PMo6V6O40 acids and an acidic pyridinium salt of H4PMo11VO40 were synthesized. They were characterized by FT-IR and the variations of their acid properties were determined by titration with n-butylamine. They proved to be highly active and selective catalysts for the hydrogen peroxide oxidation of methyl phenyl sulfide to the corresponding sulfoxide or sulfone. The conversion and selectivity

Gustavo P. Romanelli; Paula I. Villabrille; Cármen V. Cáceres; Patricia G. Vázquez; Pietro Tundo

2011-01-01

16

30 CFR 250.490 - Hydrogen sulfide.  

Code of Federal Regulations, 2010 CFR

...constructed of materials with metallurgical properties that resist or prevent sulfide stress cracking (also known as hydrogen embrittlement, stress corrosion cracking, or H2 S embrittlement), chloride-stress cracking, hydrogen-induced...

2009-07-01

17

Removal of hydrogen sulfide from drilling fluids  

Microsoft Academic Search

The present invention relates to a process for scavenging hydrogen sulfide which frequently becomes entrained in drilling fluid during the course of drilling operations through subterranean formations. The process consists of introducing a solid oxidant in powdered form into the circulating drilling fluid when hydrogen sulfide is encountered. The solid oxidants are selected from the group consisting of calcium hypochlorite

Gilligan Jr

1985-01-01

18

Hydrogen sulfide pollution in wastewater treatment facilities  

SciTech Connect

The hydrogen sulfide (H{sub 2}S) found in wastewater collection systems and wastewater treatment facilities results from the bacterial reduction of the sulfate ion (SO{sub 4}). Hydrogen sulfide is a gas that occurs both in the sewer atmosphere and as a dissolved gas in the wastewater. When raw wastewater first enters the wastewater treatment facility by gravity most of the hydrogen sulfide is in the gaseous phase and will escape into the atmosphere at the inlet structures. Also some of the dissolved hydrogen sulfide will be released at points of turbulance such as at drops in flow, flumes, or aeration chambers. Several factors can cause excessive hydrogen sulfide concentrations in a sewerage system. These include septic sewage, long flow times in the sewerage system, high temperatures, flat sewer grades, and poor ventilation. These factors are discussed in this paper.

AlDhowalia, K.H. (King Saud Univ., Riyadh (SA))

1987-01-01

19

Suicide by hydrogen sulfide inhalation.  

PubMed

The authors report a case of suicide by hydrogen sulfide in Australia. A young woman was located in a car wearing protective eyewear. A tub of foamy yellow substance and a quantity of hydrochloric acid and lime sulfur were also located in the rear of the vehicle. Morphological findings at autopsy were nonspecific. Toxicologic analysis of a specimen of leg blood detected elevated levels of methemoglobin. If Australia follows a similar trend to Japan and the United States, it is possible that incidences of such cases will rise, probably because of Internet dissemination. From a public health perspective, emergency service providers and forensic case workers should be aware of the potential hazards to themselves and others when dealing with such cases. PMID:23361075

Bott, Eleanor; Dodd, Malcolm

2013-03-01

20

Removal of hydrogen sulfide from geothermal steam  

SciTech Connect

A process for removing hydrogen sulfide from geothermal steam comprises adding free oxygen to the steam and contacting the steam with an oxidation catalyst at a pressure of at least 30 psig and a temperature not greater than the saturation temperature of the steam. The catalyst may comprise activated carbon, a refractory inorganic oxide or a metal phthalocyanine and is wetted with an aqueous solution of thiosulfates, sulfates or polysulfides. The hydrogen sulfide is converted and steam of reduced hydrogen sulfide content is obtained.

Urban, P.

1982-11-09

21

Air Pollution Aspects of Hydrogen Sulfide.  

National Technical Information Service (NTIS)

Contents: Hydrogen sulfide's effects on humans: (Odor threshold, Pollution occurrences); Effects on animals; Effects on plants; Effects on materials: (Effects on paint, Effects on metals); Environmental air standards; Natural occurrence; Production source...

S. Miner

1969-01-01

22

Removal of hydrogen sulfide from gas streams  

SciTech Connect

Hydrogen sulfide is removed from a gas stream by contacting the gas stream with an aqueous alkanolamine solution in a high surface area rotor. The solution is subjected to an acceleration greater than that due to gravity. 16 claims.

Toms, D.J.

1983-10-03

23

Hydrogen sulfide in hemostasis: friend or foe?  

PubMed

Hydrogen sulfide (H2S) is a well known toxic gas that is synthesized from the amino acids: cysteine (Cys) and homocysteine (Hcy) by three enzymes: cystathionine-?-synthase (CBS), cystathionine-?-lyase (CSE) and mercaptopyruvate sulfurtransferase (3-MST). Hydrogen sulfide, like carbon monoxide (CO) or nitric oxide (NO) is a signaling molecule in different biological systems, including the cardiovascular system. Moreover, hydrogen sulfide plays a role in the pathogenesis of various cardiovascular diseases. It modulates different elements of hemostasis (activation of blood platelet, and coagulation process) as well as proliferation and apoptosis of vascular smooth muscle cells. However, the biological role and the therapeutic potential of H2S is not clear. This review summarizes the different functions of hydrogen sulfide in hemostasis. PMID:24746521

Olas, Beata

2014-06-25

24

Hydrogen and sulfur recovery from hydrogen sulfide wastes  

DOEpatents

A process for generating hydrogen and elemental sulfur from hydrogen sulfide waste in which the hydrogen sulfide is associated under plasma conditions and a portion of the hydrogen output is used in a catalytic reduction unit to convert sulfur-containing impurities to hydrogen sulfide for recycle, the process also including the addition of an ionizing gas such as argon to initiate the plasma reaction at lower energy, a preheater for the input to the reactor and an internal adjustable choke in the reactor for enhanced coupling with the microwave energy input.

Harkness, John B. L. (Naperville, IL); Gorski, Anthony J. (Woodridge, IL); Daniels, Edward J. (Oak Lawn, IL)

1993-01-01

25

Hydrogen and sulfur recovery from hydrogen sulfide wastes  

DOEpatents

A process is described for generating hydrogen and elemental sulfur from hydrogen sulfide waste in which the hydrogen sulfide is [dis]associated under plasma conditions and a portion of the hydrogen output is used in a catalytic reduction unit to convert sulfur-containing impurities to hydrogen sulfide for recycle, the process also including the addition of an ionizing gas such as argon to initiate the plasma reaction at lower energy, a preheater for the input to the reactor and an internal adjustable choke in the reactor for enhanced coupling with the microwave energy input.

Harkness, J.B.L.; Gorski, A.J.; Daniels, E.J.

1993-05-18

26

Solubility of hydrogen sulfide in organic solvents  

Microsoft Academic Search

The solubilities of hydrogen sulfide expressed in mole fractions may be related, through multiparameter equations, to parameters\\u000a that account for the specific and nonspecific solvation ability of the solvent and for the cohesion energy. The key factors\\u000a are the self-association of the solvent, which reduces the solubility, and the complexing ability with hydrogen sulfide, which\\u000a increases the solubility.

S. D. Bryk; R. G. Makitra; E. Ya. Pal’chikova

2006-01-01

27

Desulfurization process for hydrogen sulfide containing gases  

Microsoft Academic Search

A desulfurization process for hydrogen sulfide-containing gases, which comprises contacting an alkaline aqueous medium containing a naphthoquinone sulfonate, a water-soluble compound of at least one polyvalent metal selected from the group consisting of iron, manganese, vanadium and copper, and a water-soluble high molecular compound having weight-average molecular weight of from 300 to 50,000 with a hydrogen sulfide-containing gas thereby causing

T. Sonoda; T. Kaziwara; T. Sato; F. Shimoyama

1984-01-01

28

Micro-aeration for hydrogen sulfide removal from biogas  

NASA Astrophysics Data System (ADS)

The presence of sulfur compounds (e.g. protein, sulfate, thiosulfate, sulfite, etc.) in the feed stream generates highly corrosive and odorous hydrogen sulfide during anaerobic digestion. The high sulfide level in the biogas stream is not only poisonous to many novel metal catalysts employed in thermo-catalytic processes but also reduces the quality of methane to produce renewable energy. This study used an innovative, low-maintenance, low-cost biological sulfide removal technology to remove sulfides simultaneously from both gas and liquid phase. ORP (Oxidation-Reduction-Potential) was used as the controlling parameter to precisely regulate air injection to the sulfide oxidizing unit (SOU). The microaeration technique provided just enough oxygen to partially oxidize sulfides to elemental sulfur without inhibiting methanogenesis. The SOU was equipped with a diffuser at the bottom for the dispersion of sulfide-laden biogas and injected air throughout the column. The SOU can be operated as a standalone unit or coupled with an anaerobic digester to simultaneously remove sulfide from the biogas and effluent. The integrated system was capable of reducing hydrogen sulfide in biogas from 2,450 to less than 2 ppmV with minimal sulfate production at the highest available sulfide loading rate of 0.24 kg/m3-day. More than 98% of sulfide removed was recovered as elemental sulfur. However, the standalone SOU was able to operate at high hydrogen sulfide loading of 1.46 kg/m 3-day at inlet sulfide concentration of 3000 ppmV and reduce the off-gas hydrogen sulfide concentrations to less than 10 ppmV. The experiment also revealed that the ORP controlled aeration was sensitive enough to prevent oxygen overdosing (dampening effect) during unexpected surges of aeration. Using generalized linear regression, a model predicting output H2S concentration based on input H2S concentrations, SOU medium heights, and biogas flow rates, was derived. With 95% confidence, output H2S concentration was affected by changes in liquid heights the most, followed by changes in flow rates. Feasibility studies for H2S removal from biogas by micro-aeration were conducted at the Ames Water Pollution Control Facility (AWPCF) by using different types of liquid media available at the plant, i.e. plant effluent, mixed liquor, and digester supernatant. From the experiment at AWPCF, it was found that operating pHs were affected by the amount of alkalinity in the liquid media and that the removal efficiencies were affected by the operating pH. Among all the liquid media tested, digester supernatant showed the greatest potential with more than 99% H2S removal at an operating pH of 7.0 and volumetric biogas flow rate of 21.6 m3/m 3-hr. By increasing trace metal contents and temperature of the medium, the hydrogen sulfide removal rate was greatly improved. The operating cost of the full-scale system was estimated to be approximately $2/kg-S-removed. In addition, it was also revealed that abiotic sulfide oxidation accounted for 95% of overall sulfide oxidation. This technology is expected to widen the use of biogas as a renewable fuel since the maintenance requirements of biogas handling equipment, the methane purification costs, and the emissions of SOx will dramatically be reduced. Importantly, the technology does not require inoculation of special bacteria, addition of nutrients and trace elements, or chemicals for pH control.

Duangmanee, Thanapong

29

Hydrogen Sulfide as a Gasotransmitter  

PubMed Central

Nitric oxide (NO) and carbon monoxide (CO) are well established as messenger molecules throughout the body, gasotransmitters, based on striking alterations in mice lacking the appropriate biosynthetic enzymes. Hydrogen sulfide (H2S) is even more chemically reactive, but till recently there was little definitive evidence for its physiologic formation. Cystathionine ?-synthase (CBS, EC 4.2.1.22), and Cystathionine ?-lyase (CSE; EC 4.4.1.1), also known as cytathionase, can generate H2S from cyst(e)ine. Very recent studies with mice lacking these enzymes have established that CSE is responsible for H2S formation in the periphery, while in the brain CBS is the biosynthetic enzyme. Endothelial-derived relaxing factor (EDRF) activity is reduced 80% in the mesenteric artery of mice with deletion of CSE, establishing H2S as a major physiologic EDRF. H2S appears to signal predominantly by S-sulfhydrating cysteines in its target proteins, analogous to S-nitrosylation by NO. Whereas S-nitrosylation typically inhibits enzymes, S-sulfhydration activates them. S-nitrosylation basally affects 1–2% of its target proteins, while 10–25% of H2S target proteins are S-sulfhydrated. In summary, H2S appears to be a physiologic gasotransmitter of comparable importance to NO and CO.

Gadalla, Moataz M.; Snyder, Solomon H.

2010-01-01

30

Solvation of hydrogen sulfide in liquid water and at the water-vapor interface using a polarizable force field.  

PubMed

Molecular dynamics (MD) simulations using the Drude polarizable force field are used to study the solution and interfacial properties of hydrogen sulfide (H2S) in water. Pairwise H2O-H2S Lennard-Jones interactions were optimized to the experimental H2S gas solubility at 298 K. These parameters yield hydration free energies and diffusion coefficients for H2S that are in good agreement with the experiment over 273-323 K and 298-368 K, respectively. H2S is sparingly soluble in water, with a ?G(hydr)° of -0.5 kcal mol(-1). The free energy perturbation (FEP) calculations and analysis of the radial distribution functions show that H2S has limited hydrogen bonding and electrostatic interactions with the water solvent and generally behaves like a hydrophobic solute. These features were confirmed by ab initio MD simulations. Umbrella sampling simulations were used to calculate the free energy profile of the transition of H2S across the water-vapor interface, which showed that H2S has a sizable surface excess, with a ?G(surf) of 1.3 kcal mol(-1). This high surface excess is consistent with our calculations of the surface tension, which decreases to 20 dyn cm(-1) under high densities of H2S (g). The dipole moment of H2S increases from its gas phase value of 0.98 to 1.25 D in bulk water as it moves across the interface. Adsorbed H2S tends to be oriented perpendicular to the interface, with the sulfur atom pointing toward the vapor phase. PMID:24498909

Riahi, Saleh; Rowley, Christopher N

2014-02-01

31

Hydrogen sulfide: neurochemistry and neurobiology.  

PubMed

Current evidence suggests that hydrogen sulfide (H2S) plays an important role in brain functions, probably acting as a neuromodulator as well as an intracellular messenger. In the mammalian CNS, H2S is formed from the amino acid cysteine by the action of cystathionine beta-synthase (CBS) with serine (Ser) as the by-product. As CBS is a calcium and calmodulin dependent enzyme, the biosynthesis of H2S should be acutely controlled by the intracellular concentration of calcium. In addition, it is also regulated by S-adenosylmethionine which acts as an allosteric activator of CBS. H2S, as a sulfhydryl compound, has similar reducing properties as glutathione. In neurons, H2S stimulates the production of cAMP probably by direct activation of adenylyl cyclase and thus activate cAMP-dependent processes. In astrocytes, H2S increases intracellular calcium to an extent capable of inducing and propagating a "calcium wave", which is a form of calcium signaling among these cells. Possible physiological functions of H2S include potentiating long-term potentials through activation of the NMDA receptors, regulating the redox status, maintaining the excitatory/inhibitory balance in neurotransmission, and inhibiting oxidative damage through scavenging free radicals and reactive species. H2S is also involved in CNS pathologies such as stroke and Alzheimer's disease. In stroke, H2S appears to act as a mediator of ischemic injuries and thus inhibition of its production has been suggested to be a potential treatment approach in stroke therapy. PMID:17629356

Qu, K; Lee, S W; Bian, J S; Low, C-M; Wong, P T-H

2008-01-01

32

On the Inhibition Effect of Volatile Nitrogen-Containing Bases on the Hydrogen Sulfide Corrosion of Steel  

Microsoft Academic Search

Highly basic nitrogen-containing compounds are not necessarily effective volatile inhibitors of hydrogen sulfide corrosion of steel, as distinct from the case of atmospheric corrosion. Apparently, this is due to different adsorptivities of organic compounds on oxide and sulfide films. New volatile inhibitors obtained from Schiff bases inhibit hydrogen sulfide corrosion of steel both in the liquid and vapor phases. It

Yu. I. Kuznetsov; R. K. Vagapov

2002-01-01

33

Cardioprotective effects of hydrogen sulfide  

PubMed Central

The gaseous mediator hydrogen sulfide (H2S) is synthesized mainly by cystathionine gamma-lyase in the heart and plays a role in the regulation of cardiovascular homeostasis. Here we first overview the state of the art in the literature on the cardioprotective effects of H2S in various models of cardiac injury. Subsequently, we present original data showing the beneficial effects of parenteral administration of a donor of H2S on myocardial and endothelial function during reperfusion in a canine experimental model of cardiopulmonary bypass. Overview of the literature demonstrates that various formulations of H2S exert cardioprotective effects in cultured cells, isolated hearts and various rodent and large animal models of regional or global myocardial ischemia and heart failure. In addition, the production of H2S plays a role in myocardial pre- and post-conditioning responses. The pathways implicated in the cardioprotective action of H2S are multiple and involve KATP channels, regulation of mitochondrial respiration, and regulation of cytoprotective genes such as Nrf-2. In the experimental part of the current article, we demonstrate the cardioprotective effects of H2S in a canine model of cardiopulmonary bypass surgery. Anesthetized dogs were subjected hypothermic cardiopulmonary bypass with 60 minutes of hypothermic cardiac arrest in the presence of either saline (control, n=8), or H2S infusion (1 mg/kg/h for 2 h). Left ventricular hemodynamic variables (via combined pressure-volume-conductance catheter) as well as coronary blood flow, endothelium-dependent vasodilatation to acetylcholine and endothelium-independent vasodilatation to sodium nitroprusside were measured at baseline and after 60 minutes of reperfusion. Ex vivo vascular function and high-energy phosphate contents were also measured. H2S led to a significantly better recovery of preload recruitable stroke work (p<0.05) after 60 minutes of reperfusion. Coronary blood flow was also significantly higher in the H2S group (p<0.05). While the vasodilatory response to sodium nitroprusside was similar in both groups, acetylcholine resulted in a significantly higher increase in coronary blood flow in the H2S-treated group (p<0.05) both in vivo and ex vivo. Furthermore, high-energy phosphate contents were better preserved in the H2S group. Additionally, the cytoprotective effects of H2S were confirmed also using in vitro cell culture experiments in H9c2 cardiac myocytes exposed to hypoxia and reoxygenation or to the cytotoxic oxidant hydrogen peroxide. Thus, therapeutic administration of H2S exerts cardioprotective effects in a variety of experimental models, including a significant improvement of the recovery of myocardial and endothelial function in a canine model of cardiopulmonary bypass with hypothermic cardiac arrest.

Szabo, Gabor; Veres, Gabor; Radovits, Tamas; Gero, Domokos; Modis, Katalin; Miesel-Groschel, Christiane; Horkay, Ferenc; Karck, Matthias; Szabo, Csaba

2010-01-01

34

Hydrogen sulfide to the rescue in obstructive kidney injury.  

PubMed

Hydrogen sulfide is a gasotransmitter with far-reaching effects on cell function. Studies show that, depending on the context, hydrogen sulfide can function as an ameliorative agent or as a mediator of kidney injury. PMID:24875544

Kasinath, Balakuntalam S

2014-06-01

35

Preliminary Air Pollution Survey of Hydrogen Sulfide: A Literature Review.  

National Technical Information Service (NTIS)

This is a preliminary literature review representing present knowledge of hydrogen sulfide and its effects on humans, animals, plants and materials. Hydrogen sulfide is a colorless gas that has an obnoxious odor at low concentrations. The odor threshold i...

S. Miner

1969-01-01

36

The diagenesis of carbohydrates by hydrogen sulfide  

NASA Astrophysics Data System (ADS)

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

Mango, Frank D.

1983-08-01

37

Process for removal of hydrogen sulfide from gaseous stream  

Microsoft Academic Search

This patent describes a process for removing hydrogen sulfide from a gaseous stream. It comprises contacting the hydrogen sulfide containing gaseous stream with an aqueous solution comprising a water soluble oxidized polyvalent metal chelate catalyst to convert the hydrogen sulfide to particulate elemental sulfur and reduce the polyvalent metal chelate catalyst, the contacting taking place in the presence of sufficient

S. P. Nisula; C. P. OCallaghan; G. A. Bogaczyk

1991-01-01

38

Solubility of hydrogen sulfide in n-methylpyrrolidone  

Microsoft Academic Search

The solubility of hydrogen sulfide in N-methylpyrrolidone was investigated over wide ranges of temperature and pressure. The dynamic variant of the gravimetric method was used at hydrogen sulfide pressures equal to or below atmospheric, and the static variant at higher pressures. In the dynamic variant of the gravimetric method hydrogen sulfide is passed through a known amount of solvent until

N. L. Yarym-Agaev; V. G. Matvienko; N. V. Povalyaeva

1980-01-01

39

BURST RELEASES OF HYDROGEN SULFIDE IN MECHANICALLY VENTILATED SWINE BUILDINGS  

Microsoft Academic Search

ABSTRACT Hydrogen sulfide (H2S) is an odorous gas produced from animal manure. It is toxic to humans and animals at high concentrations. There is little understanding about its release behavior from stored liquid swine manure. This paper documents,burst releases of H2S recorded with a state-of-the-art field measurement system in two commercial swine buildings over a six-month period. The 1,000- head

Ji-qin Ni; Albert J. Heber; Claude A. Diehl; Teng T. Lim; R. K. Duggirala; B. L. Haymore

40

Process for producing hydrogen and carbonyl sulfide from hydrogen sulfide and carbon monoxide using a heteropolyanionic metal complex catalyst  

SciTech Connect

Hydrogen and carbonyl sulfide are produced by a process comprising contracting gaseous hydrogen sulfide with gaseous carbon monoxide in the presence of a heteropolymolybdate or tungstate complex. Use of these catalysts reduce the amount of by-product carbon dioxide and methane formation and thus enhance the make of hydrogen and carbonyl sulfide.

Kuch, Ph. L.

1984-12-18

41

Mechanisms of hydrogen sulfide removal with steel making slag.  

PubMed

In the present study, we experimentally investigated the removal of hydrogen sulfide using steel-making slag (SMS) and clarified the mechanism of hydrogen sulfide removal with the SMS. The results proved that SMS is able to remove hydrogen sulfide dissolved in water, and the maximum removal amount of hydrogen sulfide per unit weight of the SMS for 8 days was estimated to be 37.5 mg S/g. The removal processes of hydrogen sulfide were not only adsorption onto the SMS, but oxidation and precipitation as sulfur. The chemical forms of sulfide adsorbed onto the SMS were estimated to be sulfur and manganese sulfide in the ratio of 81% and 19%, respectively. It is demonstrated here that the SMS is a promising material to remediate organically enriched coastal sediments in terms of removal of hydrogen sulfide. Furthermore, using SMS is expected to contribute to development of a recycling-oriented society. PMID:22894171

Kim, Kyunghoi; Asaoka, Satoshi; Yamamoto, Tamiji; Hayakawa, Shinjiro; Takeda, Kazuhiko; Katayama, Misaki; Onoue, Takasumi

2012-09-18

42

Removal of hydrogen sulfide from drilling fluids  

SciTech Connect

The present invention relates to a process for scavenging hydrogen sulfide which frequently becomes entrained in drilling fluid during the course of drilling operations through subterranean formations. The process consists of introducing a solid oxidant in powdered form into the circulating drilling fluid when hydrogen sulfide is encountered. The solid oxidants are selected from the group consisting of calcium hypochlorite (Ca-(OCl)/sub 2/), sodium perborate (NaBO/sub 3/), potassium permanganate (KMnO/sub 4/), and potassium peroxydisulfate (K/sub 2/S/sub 2/O/sub 8/). The solid oxidants are soluble in the drilling fluid, promoting fast and complete scavenging reactions without adversely altering the drilling fluid rheology.

Gilligan Jr., T. J.

1985-10-22

43

Hydrogen sulfide determination by solid surface luminescence.  

PubMed

In the analytical system suggested, atmospheric hydrogen sulfide reacts with the surface of a filter paper treated with aqueous cadmium chloride and yields a luminescent species whose intensity can be correlated with the analyte concentration in ambient air. It was shown that the luminescent species are CdS solid particles which were formed in a well defined size. The paper luminescence was also tried on polymeric surfaces; polyethyleneoxide, polyvinyl alcohol, ethylcellulose and carboxymethylcellulose were found to give a similar luminescence signal. The system can be used on the tip of an optical fiber for an irreversible, cumulative type of analytical device for hydrogen sulfide determination. The 3s detection limit for the paper luminescence detection system was 7.8 ppb H(2)S. PMID:15045337

Ero?lu, A E; Volkan, M; Bayramh, E; Ataman, O Y; Mark, H B

1996-06-01

44

Hydrogen sulfide: its production, release and functions  

Microsoft Academic Search

Hydrogen sulfide (H2S), which is a well-known toxic gas, has been recognized as a signal molecule as well as a cytoprotectant. It is produced\\u000a by three enzymes, cystathionine ?-synthase, cystathionine ?-lyase and 3-mercaptopyruvate sulfurtransferase along with cysteine\\u000a aminotransferase. In addition to an immediate release of H2S from producing enzymes, it can be stored as bound sulfane sulfur, which may release

Hideo Kimura

2011-01-01

45

Hydrogen sulfide and ischemia–reperfusion injury  

Microsoft Academic Search

Gasotransmitters are lipid soluble, endogenously produced gaseous signaling molecules that freely permeate the plasma membrane of a cell to directly activate intracellular targets, thus alleviating the need for membrane-bound receptors. The gasotransmitter family consists of three members: nitric oxide (NO), carbon monoxide (CO), and hydrogen sulfide (H2S). H2S is the latest gasotransmitter to be identified and characterized and like the

Chad K. Nicholson; John W. Calvert

2010-01-01

46

Second dissociation constant of hydrogen sulfide  

Microsoft Academic Search

Published values for the pK\\/sub a\\/â values of hydrogen sulfide cover a range of almost 8 orders of magnitude. In this study a Raman spectrometric method is used for in situ identification of the H-S stretch in high-ph solutions and for estimating their concenrations. The data presented here yield a pK\\/sub a\\/â value of 17 +lt. slash- 1.0, the highest

B. Meyer; K. Ward; K. Koshlap; L. Peter

1983-01-01

47

Recovery of hydrogen from hydrogen sulfide with metals or metal sulfides  

NASA Astrophysics Data System (ADS)

Two types of reactions for the recovery of hydrogen from hydrogen sulfide using metals or metal sulfides are investigated. The first type of reaction, which involved the sulfurization of metals or metal sulfides with H2S and the thermal decomposition of the products into hydrogen, elemental sulfur and the original metals or metal sulfide, was studied by the measurement of H2 evolution in a packed bed of powders of Ag, FeS, Co9S8, Ni3S2 and various sulfide mixtures. The second type of reaction involves the sulfurization of a metal by H2S and the recovery of the metal by the oxidation of the metal sulfides formed, and was studied for the case of molten lead, molten lead with the addition of Ni or Co, Ag, Cu and Ni powders, and molten Ag-Bi alloy. Extents of reaction and temperature dependence were determined for each step of the reactions, and the repeatability of the cycles was examined.

Kiuchi, H.; Nakamura, I.; Funaki, K.; Tanaka, T.

48

Method for removing hydrogen sulfide from gas streams  

Microsoft Academic Search

A hydrogen sulfide removal and conversion method is disclosed in which a hydrogen sulfide-containing gas stream is contacted with a substantially quinone-free aqueous washing solution containing, inter alia, solubilized vanadium, thiocyanate ions, and one or more water-soluble nonquinone aromatic compounds capable of solubilizing tetravalent vanadium. The absorbed hydrogen sulfide is converted to elemental sulfur which, after oxidative regeneration of the

D. M. Fenton; H. W. Gowdy

1981-01-01

49

Process for purifying an aqueous, hydrogen sulfide-scrubbing solution  

Microsoft Academic Search

This patent describes a process for purifying an aqueous hydrogen sulfide-scrubbing solution containing a water-soluble vanadium component and a water-soluble organic compound, the scrubbing solution being capable of absorbing hydrogen sulfide and converting the hydrogen sulfide into elemental sulfur. The process comprises: forming a slurry by mixing the scrubbing solution with particles of a spent solid catalyst containing molybdenum and

J. W. Koepke; D. D. Delaney

1989-01-01

50

Catalytic removal of hydrogen sulfide from geothermal fluids  

Microsoft Academic Search

UOP Sulfox technology successfully removed 500 ppm hydrogen sulfide from simulated mixed phase geothermal waters. The Sulfox process involves air oxidation of hydrogen sulfide using a fixed catalyst bed. The catalyst activity remained stable through the life of the program. The distribution of hydrogen sulfide conversion products was affected by the pH; low pH favored elemental sulfur, whereas high pH

P. Urban; S. N. Massie

1981-01-01

51

Hydrogen sulfide and carbon dioxide removal from dry fuel gas streams using an ionic liquid as a physical solvent  

SciTech Connect

The mole fraction solubilities (x{asterisk}) and volumetric liquid-side mass-transfer coefficients (kLa) for H{sub 2}S and CO{sub 2} in the ionic liquid, TEGO IL K5, (a quaternary ammonium polyether) were measured under different pressures (up to 30 bar) and temperatures (up to 500 K) in a 4 L ZipperClave agitated reactor. CO{sub 2} and N{sub 2}, as single gases, and a H{sub 2}S/N{sub 2} gaseous mixture were used in the experiments. The solubilities of H{sub 2}S and CO{sub 2} were found to increase with pressure and decrease with temperature within the experimental conditions used. The H{sub 2}S solubilities in the ionic liquid (IL) were greater than those of CO{sub 2} within the temperature range investigated (300-500 K) up to a H{sub 2}S partial pressure of 2.33 bar. Hence, the IL can be effectively used to capture both H{sub 2}S and CO{sub 2} from dry fuel gas stream within the temperature range from 300 to 500 K under a total pressure up to 30 bar. The presence of H{sub 2}S in the H{sub 2}S/N{sub 2} mixture created mass-transfer resistance, which decreased k{sub L}{alpha} values for N{sub 2}. The k{sub L}{alpha} and x{asterisk} values of CO{sub 2} were found to be greater than those of N{sub 2} in the IL, which highlight the stronger selectivity of this physical solvent toward CO{sub 2} than toward N{sub 2}. In addition, within the temperature range from 300 to 500 K, the solubility and k{sub L}{alpha} of H{sub 2}S in the IL were greater than those of CO{sub 2}, suggesting that not only can H{sub 2}S be more easily captured from dry fuel gas streams but also a shorter absorber can be employed for H{sub 2}S capture than that for CO{sub 2}. 56 refs., 8 figs., 4 tabs.

Yannick J. Heintz; Laurent Sehabiague; Badie I. Morsi; Kenneth L. Jones; David R. Luebke; Henry W. Pennline [United States Department of Energy (U.S. DOE), Pittsburgh, PA (United States). National Energy Technology Laboratory

2009-09-15

52

Hydrogen sulfide inhibits the renal fibrosis of obstructive nephropathy  

PubMed Central

Hydrogen sulfide has recently been found decreased in chronic kidney disease. Here we determined the effect and underlying mechanisms of hydrogen sulfide on a rat model of unilateral ureteral obstruction. Compared with normal rats, obstructive injury decreased the plasma hydrogen sulfide level. Cystathionine-?-synthase, a hydrogen sulfide-producing enzyme, was dramatically reduced in the ureteral obstructed kidney, but another enzyme cystathionine-?-lyase was increased. A hydrogen sulfide donor (sodium hydrogen sulfide) inhibited renal fibrosis by attenuating the production of collagen, extracellular matrix, and the expression of ?-smooth muscle actin. Meanwhile, the infiltration of macrophages and the expression of inflammatory cytokines including interleukin-1?, tumor necrosis factor-?, and monocyte chemoattractant protein-1 in the kidney were also decreased. In cultured kidney fibroblasts, a hydrogen sulfide donor inhibited the cell proliferation by reducing DNA synthesis and downregulating the expressions of proliferation-related proteins including proliferating cell nuclear antigen and c-Myc. Further, the hydrogen sulfide donor blocked the differentiation of quiescent renal fibroblasts to myofibroblasts by inhibiting the transforming growth factor-?1-Smad and mitogen-activated protein kinase signaling pathways. Thus, low doses of hydrogen sulfide or its releasing compounds may have therapeutic potentials in treating chronic kidney disease.

Song, Kai; Wang, Fen; Li, Qian; Shi, Yong-Bing; Zheng, Hui-Fen; Peng, Hanjing; Shen, Hua-Ying; Liu, Chun-Feng; Hu, Li-Fang

2014-01-01

53

Hydrogen sulfide inhibits the renal fibrosis of obstructive nephropathy.  

PubMed

Hydrogen sulfide has recently been found decreased in chronic kidney disease. Here we determined the effect and underlying mechanisms of hydrogen sulfide on a rat model of unilateral ureteral obstruction. Compared with normal rats, obstructive injury decreased the plasma hydrogen sulfide level. Cystathionine-?-synthase, a hydrogen sulfide-producing enzyme, was dramatically reduced in the ureteral obstructed kidney, but another enzyme cystathionine-?-lyase was increased. A hydrogen sulfide donor (sodium hydrogen sulfide) inhibited renal fibrosis by attenuating the production of collagen, extracellular matrix, and the expression of ?-smooth muscle actin. Meanwhile, the infiltration of macrophages and the expression of inflammatory cytokines including interleukin-1?, tumor necrosis factor-?, and monocyte chemoattractant protein-1 in the kidney were also decreased. In cultured kidney fibroblasts, a hydrogen sulfide donor inhibited the cell proliferation by reducing DNA synthesis and downregulating the expressions of proliferation-related proteins including proliferating cell nuclear antigen and c-Myc. Further, the hydrogen sulfide donor blocked the differentiation of quiescent renal fibroblasts to myofibroblasts by inhibiting the transforming growth factor-?1-Smad and mitogen-activated protein kinase signaling pathways. Thus, low doses of hydrogen sulfide or its releasing compounds may have therapeutic potentials in treating chronic kidney disease. PMID:24284510

Song, Kai; Wang, Fen; Li, Qian; Shi, Yong-Bing; Zheng, Hui-Fen; Peng, Hanjing; Shen, Hua-Ying; Liu, Chun-Feng; Hu, Li-Fang

2014-06-01

54

Oxidative removal of hydrogen sulfide from gas streams  

SciTech Connect

A method is described for recovering elemental sulfur and selectively removing hydrogen sulfide from a hydrogen sulfide containing sour gas stream also containing carbon dioxide. The method consists of: (a) contacting the hydrogen sulfide containing sour gas stream in a first reaction zone with a buffered aqueous solution enriched in thiosulfate ions at a pH between 4.5 and 6.5 for a residence time sufficient to react a portion of the hydrogen sulfide to elemental sulfur and thereby produce a single gas stream lean in hydrogen sulfide and a separate aqueous solution lean in thiosulfate ions, the aqueous solution containing elemental sulfur; (b) separating the elemental sulfur from the aqueous solution lean in thiosulfate ions; (c) contacting the single gas stream lean in hydrogen sulfide from the first reaction zone with an oxygen-containing gas and the aqueous solution lean in thiosulfate ions in a second reaction zone at an initial acid to neutral pH greater than the pH in the first reaction zone for a residence time sufficient to enrich the thiosulfate ion concentration of the aqueous solution and to produce a hydrogen sulfide depleted product gas stream; (d) removing the hydrogen sulfide depleted product gas stream from the second reaction zone; and (e) recycling the aqueous solution enriched in thiosulfate ions without change in composition to the first reaction zone.

Cronkright, W.A.; Schlossman, M.I.; Solbakken, A.; Van Dijk, C.P.

1986-04-01

55

Hydrogen sulfide removal with sulfur-containing esters  

SciTech Connect

Sulfur-containing esters, such as dimethyldithiodipropionate, are excellent solvents for hydrogen sulfide and can be used for the purification of gas streams containing hydrogen sulfide. The obtained solution can be stored and used as H/sub 2/S source.

Gordon, B.W.; Huxley, E.E.

1982-09-07

56

Process of removing hydrogen sulfide from gas mixtures  

Microsoft Academic Search

This patent describes a process for selectively removing hydrogen sulfide from a gas mixture. It comprises: treating a gas mixture comprising natural gas, hydrogen sulfide and carbon dioxide with an aqueous medium containing an effective amount of an inorganic water soluble metal sodium nitrite, the aqueous medium being buffered to a pH of about 5.5 or greater.

E. E. Burnes; K. Bhatia

1989-01-01

57

Sulfides in the Anaerobic Environment: The Determination of Hydrogen Sulfide and Acid-Soluble Metallic Sulfides in Sea-Floor Sediment  

Microsoft Academic Search

A procedure for the determination of hydrogen sulfide and acid-soluble metallic sulfides in sea floor sediment has been developed and tested as part of a laboratory course in analytical and environmental chemistry. The procedure includes (i) anaerobic sampling of sediment, (ii) a volatilization method, which discriminates between hydrogen sulfide and acid-soluble metallic sulfides in the sediment, and (iii) a quantitative

Joan Kai Christensen; Boy Høyer; Lars Kryger; Niels Pind; Lee Sing Kong

1998-01-01

58

Responsive lanthanide coordination polymer for hydrogen sulfide.  

PubMed

Metal organic coordination polymers have received great attention because of their flexible compositions and architecture. Here, we report the design and synthesis of a responsive lanthanide coordination polymer (LCP) for hydrogen sulfide (H2S), utilizing self-assembling of biomolecule nucleotide with luminescent terbium ion (Tb(3+)) and sensitizing silver ion (Ag(+)) in aqueous solution. LCP is highly fluorescent due to the inclusion of Ag(+) ions, which sensitized the fluorescence of Tb(3+) ions. H2S can strongly quench the fluorescence of LCP through its high affinity for Ag(+) ions. Such configurated LCP material from initial building blocks showed high sensitivity and selectivity for H2S and was applied to the determination of H2S in human serum. LCP with Tb(3+) ions also has a long fluorescence lifetime, which allows for time-resolved fluorescence assays, possessing particular advantages to probing H2S in biological systems with autofluorescence. PMID:24191713

Liu, Baoxia; Chen, Yang

2013-11-19

59

Hydrogen sulfide exposure in an adult male  

PubMed Central

Hydrogen sulfide (H2S) is responsible for many incidents of occupational toxic exposure, especially in the petroleum industry. The clinical effects of H2S depend on its concentration and the duration of exposure. H2S is immediately fatal when concentrations are over 500-1000 parts per million (ppm) but exposure to lower concentrations, such as 10-500 ppm, can cause various respiratory symptoms that range from rhinitis to acute respiratory failure. H2S may also affect multiple organs, causing temporary or permanent derangements in the nervous, cardiovascular, renal, hepatic, and hematological systems. We present a case of occupational exposure to H2S leading to multi-organ involvement, acute respiratory failure, organizing pneumonia, and shock resembling acute sepsis. The patient also developed mild obstructive and restrictive pulmonary disease and peripheral neuropathy.

Doujaiji, Bassam; Al-Tawfiq, Jaffar A.

2010-01-01

60

Fluorescent probes for sensing and imaging biological hydrogen sulfide  

PubMed Central

Hydrogen sulfide (H2S) has long been recognized as a toxic molecule in biological systems. However, emerging studies now link controlled fluxes of this reactive sulfur species to cellular regulation and signaling events akin to other small molecule messengers, such as nitric oxide, hydrogen peroxide, and carbon monoxide. Progress in the development of fluorescent small-molecule indicators with high selectivity for hydrogen sulfide offers a promising approach for studying its production, trafficking, and downstream physiological and/or pathological effects.

Lin, Vivian S; Chang, Christopher J

2012-01-01

61

Hydrogen Production from Hydrogen Sulfide in IGCC Power Plants  

SciTech Connect

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

Elias Stefanakos; Burton Krakow; Jonathan Mbah

2007-07-31

62

Direct electrical measurement of the conversion of metal acetates to metal sulfides by hydrogen sulfide.  

PubMed

Copper acetate and related metal salt films react directly with hydrogen sulfide at room temperature to form metal sulfides, resulting in conductivity changes as large as 108. The observed changes in conductivity are related to the solubility product constant (Ksp) and the difference in conductivity between the metal salt and the resulting metal sulfide. A smaller Ksp indicates a more stable metal sulfide and, therefore, greater metal salt reactivity. Polyaniline nanofiber/metal salt composites were also examined and show metal sulfide conversion with changes in resistance up to 106. The direct electrical measurement of the conversion of metal salt to metal sulfide has the potential to be the basis of a new type of sensitive, thin-film chemical sensor. PMID:17173401

Virji, Shabnam; Kaner, Richard B; Weiller, Bruce H

2006-12-25

63

Solubility of hydrogen sulfide in aqueous solutions of single strong electrolytes sodium nitrate, ammonium nitrate, and sodium hydroxide at temperatures from 313 to 393 K and total pressures up to 10 MPa  

Microsoft Academic Search

New experimental results for the solubility of hydrogen sulfide in aqueous solutions of the single strong electrolytes sodium nitrate, ammonium nitrate, and sodium hydroxide at temperatures from 313 to 393 K and total pressures up to 10 MPa are reported. As in the strong electrolyte-free system, a second — hydrogen sulfide-rich — liquid phase is observed at high hydrogen sulfide

Jianzhong Xia; Álvaro Pérez-Salado Kamps; Bernd Rumpf; Gerd Maurer

2000-01-01

64

Determination of hydrogen sulfide and volatile thiols in air samples by mercury probe derivatization coupled with liquid chromatography–atomic fluorescence spectrometry  

Microsoft Academic Search

A new procedure is proposed for the sampling and storage of hydrogen sulphide (H2S) and volatile thiols (methanethiol or methyl mercaptan, ethanethiol and propanethiol) for their determination by liquid chromatography. The sampling procedure is based on the trapping\\/pre-concentration of the analytes in alkaline aqueous solution containing an organic mercurial probe p-hydroxymercurybenzoate, HO–Hg–C6H4–COO? (PHMB), where they are derivatized to stable PHMB

Emilia Bramanti; Lucia D’Ulivo; Cristina Lomonte; Massimo Onor; Roberto Zamboni; Giorgio Raspi; Alessandro D’Ulivo

2006-01-01

65

Oxygen-hydrogen sulfide intermediate layer of the Black Sea  

SciTech Connect

Spatial and vertical boundaries were studied for the oxygen-hydrogen sulfide intermediate layer in the Black Sea. The wind has a great influence on the thermohaline structure of the Danube coastal waters. It causes strong out-and-influx processes and up-welling of hydrogen sulfide waters of the intermediate layer in the north-western part of the Black Sea, which is supposed to be one of the reasons for the ecological equilibrium disturbance in this region.

Timoshchuk, V.I.; Risik, N.S.

1980-01-01

66

Experimental study of polysulfane stability in gaseous hydrogen sulfide  

Microsoft Academic Search

The solubility of sulfur in gaseous hydrogen sulfide has been studied in the H2S-S system. Experiments were carried out at temperatures between 50 and 290°C and pressures up to 200 bars. The experimentally determined concentrations of sulfur in the gas phase are 6–7 orders of magnitude higher than the corresponding concentrations calculated for a system free of hydrogen sulfide. The

Art A. Migdisov; O. M. Suleimenov; Yu. V. Alekhin

1998-01-01

67

Method for removing hydrogen sulfide from gas streams  

Microsoft Academic Search

A hydrogen sulfide removal and conversion method in which a hydrogen sulfide-containing gas stream is contacted with a regenerable washing solution having a pH between about 5 and about 10 and containing solubilized vanadium, thiocyanate ions, a carboxylate complexing agent, one or more water-soluble quinones and one or more water-soluble nonquinone aromatic compounds capable of solubilizing tetravalent vanadium. The absorbed

H. W. Gowdy; D. M. Fenton

1984-01-01

68

Method for removing hydrogen sulfide from gas streams  

Microsoft Academic Search

A hydrogen sulfide removal and conversion method in which a hydrogen sulfide-containing gas stream is contacted with a regenerable washing solution containing solubilized vanadium thiocyanate ions, a carboxylate complexing agent and one or more water-soluble quinones capable of solubilizing tetravalent vanadium. The molar ratio of vanadium to quinone(S) in the washing solution is selected to substantially reduce or eliminate the

D. M. Fenton; H. W. Gowdy

1982-01-01

69

Hydrogen Sulfide and Hemeproteins: Knowledge and Mysteries  

PubMed Central

Abstract Historically, hydrogen sulfide (H2S) has been regarded as a poisonous gas, with a wide spectrum of toxic effects. However, like?·NO and CO, H2S is now referred to as a signaling gas involved in numerous physiological processes. The list of reports highlighting the physiological effects of H2S is rapidly expanding and several drug candidates are now being developed. As with?·NO and CO, not a single H2S target responsible for all the biological effects has been found till now. Nevertheless, it has been suggested that H2S can bind to hemeproteins, inducing different responses that can mediate its effects. For instance, the interaction of H2S with cytochrome c oxidase has been associated with the activation of the ATP-sensitive potassium channels, regulating muscle relaxation. Inhibition of cytochrome c oxidase by H2S has also been related to inducing a hibernation-like state. Although H2S might induce these effects by interacting with hemeproteins, the mechanisms underlying these interactions are obscure. Therefore, in this review we discuss the current state of knowledge about the interaction of H2S with vertebrate and invertebrate hemeproteins and postulate a generalized mechanism. Our goal is to stimulate further research aimed at evaluating plausible mechanisms that explain H2S reactivity with hemeproteins. Antioxid. Redox Signal. 15, 393–404.

Pietri, Ruth; Roman-Morales, Elddie

2011-01-01

70

Hydrogen Sulfide and Ischemia - Reperfusion Injury  

PubMed Central

Gasotransmitters are lipid soluble, endogenously produced gaseous signaling molecules that freely permeate the plasma membrane of a cell to directly activate intracellular targets, thus alleviating the need for membrane-bound receptors. The gasotransmitter family consists of three members: nitric oxide (NO), carbon monoxide (CO), and hydrogen sulfide (H2S). H2S is the latest gasotransmitter to be identified and characterized and like the other members of the gasotransmitter family, H2S was historically considered to be a toxic gas and an environmental/occupational hazard. However with the discovery of its presence and enzymatic production in mammalian tissues, H2S has gained much attention as a physiological signaling molecule. Also, much like NO and CO, H2S’s role in ischemia/reperfusion (I/R) injury has recently begun to be elucidated. As such, modulation of endogenous H2S and administration of exogenous H2S has now been demonstrated to be cytoprotective in various organ systems through diverse signaling mechanisms. This review will provide a detailed description of the role H2S plays in different model systems of I/R injury and will also detail some of the mechanisms involved with its cytoprotection.

Nicholson, Chad K.; Calvert, John W.

2010-01-01

71

Addition of hydrogen sulfide to juglone.  

PubMed

Evidence of the addition of hydrogen sulfide to 5-hydroxy-1,4-naphthoquinone (juglone) in aqueous solution was obtained by nuclear magnetic resonance spectrometry (NMR), electron paramagnetic resonance spectrometry (EPR), UV-visible absorbance spectroscopy, and kinetic measurements. Although numerous addition reactions of thiolated alkane and aromatic compounds to quinones have been previously reported, this study indicates that inorganic forms of S(-II) act as nucleophiles and electrophiles in addition reactions to the alpha,beta-conjugated system of the quinone. The results obtained are consistent with competing Michael and radical addition reactions, with radical addition favored with increasing pH. The simplest structure that simulated the NMR spectrum was a sulfur molecule containing sulfur bonded between two juglone molecules at C-2 or C-3, while EPR measurements of aqueous reaction solutions indicated the presence of a stable semiquinone that contained a sulfur substituent at C-2 or C-3. Quinones are present in trace amounts in natural organic matter, and the addition of S(-II) has important implications with respect to transport and transformation of a variety of compounds that react with natural organic matter. PMID:12099462

Perlinger, J A; Kalluri, V M; Venkatapathy, R; Angst, W

2002-06-15

72

Hydrogen sulfide as a vasculoprotective factor  

PubMed Central

Hydrogen sulfide is a novel mediator with the unique properties of a gasotransmitter and many and varied physiological effects. Included in these effects are a number of cardiovascular effects that are proving beneficial to vascular health. Specifically, H2S can elicit vasorelaxation, prevention of inflammation and leukocyte adhesion, anti-proliferative effects and anti-thrombotic effects. Additionally, H2S is a chemical reductant and nucleophile that is capable of inhibiting the production of reactive oxygen species, scavenging and neutralising reactive oxygen species and boosting the efficacy of endogenous anti-oxidant molecules. These result in resistance to oxidative stress, protection of vascular endothelial function and maintenance of blood flow and organ perfusion. H2S has been shown to be protective in hypertension, atherosclerosis and under conditions of vascular oxidative stress, and deficiency of endogenous H2S production is linked to cardiovascular disease states. Taken together, these effects suggest that H2S has a physiological role as a vasculoprotective factor and that exogenous H2S donors may be useful therapeutic agents. This review article will discuss the vascular effects and anti-oxidant properties of H2S as well as examine the protective role of H2S in some important vascular disease states.

2013-01-01

73

Thermochemical decomposition of hydrogen sulfide with nickel sulfide  

NASA Astrophysics Data System (ADS)

In this research, the two-step thermochemical cycle shown below is proposed and experimental studies were made on the cycle. begin{gathered} {text{Ni}}_{text{3}} {text{S}}_{text{2}} + {text{H}}_{text{2}} {text{S}} = {text{3NiS + H}}_{text{2}} \\ {text{3NiS = Ni}}_{text{3}} {text{S}}_{text{2}} {text{ + 0}/text{.5S}_{text{2}} {text{(g)}} \\ }{{{text{H}}_{text{2}} {text{S = H}}_{text{2}} {text{ + 0}}{text{.5S}}_{text{2}} {text{(g)}}}} In the case where Ni3S2 alone was used without inert additions, nickel sulfide sintered or partly fused due to the melting point depression resulting from the thermal decomposition of formed NiS. Such sintering could be prevented by mixing the nickel sulfide powders with Al2O3 or MoS2. The cyclic reactions were thereby shown to provide a stationary high decomposition rate of H2S. Polysulfides, such as MS2, have previously been employed in this kind of cycle. This research showed that the use of lower sulfides such as Ni3S2 may be regarded as rather promising based on the thermodynamic investigation of the respective reactions composing the cycle. The comparison between the sulfurization reactions of NiS to NiS2 and of Ni3S2 to NiS further showed that the latter was superior to the former with respect to the kinetics and thermodynamical properties of the reaction.

Kiuchi, Hiromichi; Funaki, Kimio; Tanaka, Tokiaki

1983-09-01

74

Hydrogen Sulfide in Biochemistry and Medicine  

PubMed Central

Abstract Significance: An abundance of experimental evidence suggests that hydrogen sulfide (H2S) plays a prominent role in physiology and pathophysiology. Many targets exist for H2S therapy. The molecular targets of H2S include proteins, enzymes, transcription factors, and membrane ion channels. Recent Advances: Novel H2S precursors are being synthesized and discovered that are capable of releasing H2S in a slow and sustained manner. This presents a novel and advantageous approach to H2S therapy for treatment of chronic conditions associated with a decline in endogenous H2S, such as diabetes and cardiovascular disease. Critical Issues: While H2S is cytoprotective at physiological concentrations, it is not universally cytoprotective, as it appears to have pro-apoptotic actions in cancer cells and is well known to be toxic at supraphysiological concentrations. Many of the pleiotropic effects of H2S on health are associated with the inhibition of inflammation and upregulation of prosurvival pathways. The powerful anti-inflammatory, cytoprotective, immunomodulating, and trophic effects of H2S on the vast majority of normal cells seem to be mediated mainly by its actions as an extremely versatile direct and indirect antioxidant and free radical scavenger. While the overall effects of H2S on transformed (i.e., malignant) cells can be characterized as pro-oxidant and pro-apoptotic, they contrast sharply with the cytoprotective effects on most normal cells. Future Directions: H2S has become a molecule of great interest, and several slow-releasing H2S prodrugs are currently under development. We believe that additional agents regulating H2S bioavailability will be developed during the next 10 years. Antioxid. Redox Signal. 17, 119–140.

Predmore, Benjamin Lee; Lefer, David Joseph

2012-01-01

75

Vertebrate phylogeny of hydrogen sulfide vasoactivity.  

PubMed

Hydrogen sulfide (H(2)S) is a recently identified endogenous vasodilator in mammals. In steelhead/rainbow trout (Oncorhynchus mykiss, Osteichthyes), H(2)S produces both dose-dependent dilation and a unique dose-dependent constriction. In this study, we examined H(2)S vasoactivity in all vertebrate classes to determine whether H(2)S is universally vasoactive and to identify phylogenetic and/or environmental trends. H(2)S was generated from NaHS and examined in unstimulated and precontracted systemic and, when applicable, pulmonary arteries (PA) from Pacific hagfish (Eptatretus stouti, Agnatha), sea lamprey (Petromyzon marinus, Agnatha), sandbar shark (Carcharhinus milberti, Chondrichthyes), marine toad (Bufo marinus, Amphibia), American alligator (Alligator mississippiensis, Reptilia), Pekin duck (Anas platyrhynchos domesticus, Aves), and white rat (Rattus rattus, Mammalia). In otherwise unstimulated vessels, NaHS produced 1) a dose-dependent relaxation in Pacific hagfish dorsal aorta; 2) a dose-dependent contraction in sea lamprey dorsal aorta, marine toad aorta, alligator aorta and PA, duck aorta, and rat thoracic aorta; 3) a threshold relaxation in shark ventral aorta, dorsal aorta, and afferent branchial artery; and 4) a multiphasic contraction-relaxation-contraction in the marine toad PA, duck PA, and rat PA. Precontraction of these vessels with another agonist did not affect the general pattern of NaHS vasoactivity with the exception of the rat aorta, where relaxation was now dominant. These results show that H(2)S is a phylogenetically ancient and versatile vasoregulatory molecule that appears to have been opportunistically engaged to suit both organ-specific and species-specific homeostatic requirements. PMID:15345473

Dombkowski, Ryan A; Russell, Michael J; Schulman, Alexis A; Doellman, Meredith M; Olson, Kenneth R

2005-01-01

76

Determination of Hydrogen Sulfide in Fermentation Broths Containing SO21  

PubMed Central

A procedure for the determination of hydrogen sulfide in fermentation broths containing up to 100 ?g 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.

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

1971-01-01

77

Identification of Genes Affecting Hydrogen Sulfide Formation in Saccharomyces cerevisiae  

Microsoft Academic Search

A screen of the Saccharomyces cerevisiae deletion strain set was performed to identify genes affecting hydrogen sulfide (H2S) production. Mutants were screened using two assays: colony color on BiGGY agar, which detects the basal level of sulfite reductase activity, and production of H2S in a synthetic juice medium using lead acetate detection of free sulfide in the headspace. A total

Angela L. Linderholm; Carrie L. Findleton; Gagandeep Kumar; Yeun Hong; Linda F. Bisson

2008-01-01

78

Process for the production of hydrogen and carbonyl sulfide from hydrogen sulfide and carbon monoxide using a multi-metal oxide/sulfide catalyst  

SciTech Connect

Hydrogen and carbonyl sulfide are produced by a process comprising contacting gaseous hydrogen sulfide with gaseous carbon monoxide in the presence of a catalytic composition containing an oxide and/or sulfide of at least one of molybdenum, tungsten, iron, chromium and vanadium in combination with at least one promoter metal, e.g. a catalyst of the formula Cs Cu /SUB 0.2/ Zn /SUB 0.5/ Mn /SUB 0.5/ Sn /SUB 2.4/ Mo O /SUB x/ S /SUB y/ .

Jevnikar, M. G.; Kuch, Ph. L.

1985-02-19

79

Physiological function of hydrogen sulfide and beyond.  

PubMed

The relatively high concentrations of endogenous sulfide in the mammalian brain were measured in 1989, suggesting that hydrogen sulfide (H2S) might have a physiological function. In 1996 we demonstrated that cystathionine ?-synthase (CBS) is a H2S producing enzyme in the brain and that H2S facilitates the induction of hippocampal long-term potentiation (LTP), a synaptic model of memory, by enhancing the activity of N-methyl d-aspartate (NMDA) receptors. The following year we demonstrated that another H2S producing enzyme, cystathionine ?-lyase (CSE) is found in tissues including vasculature and that H2S relaxes them. Based on these observations we proposed that H2S is a neuromodulator and a smooth muscle relaxant. In addition to the function as a signaling molecule, we and others found a cytoprotective effect of this molecule; H2S protects neurons from oxidative stress. This finding led to the identification of the protection of various organs including the heart, pancreas, retina, and the kidney against ischemia-reperfusion injury. From our finding that the brains of CBS knockout mice was still able to produce H2S, we found another pathway; 3-mercaptopyruvate sulfur transferase (3MST) along with cysteine aminotransferase (CAT). 3MST produces H2S in the presence of thioredoxin or dihydrolipoic acid (DHLA). We recently found a novel pathway to produce H2S from d-cysteine, a negative control. d-Amino acid oxidase (DAO) metabolizes d-cysteine to an achiral ?-keto acid, 3-mercaptopyruvate (3MP), which is further metabolized to H2S by 3MST. This pathway is mainly localized in the cerebellum and the kidney. The production of H2S from d-cysteine is 80 times more efficient than that from l-cysteine in the kidney, and the administration of d-cysteine to mice ameliorates renal ischemia-reperfusion injury more effectively than l-cysteine. These results show a therapeutic potential of d-cysteine to the renal diseases and even to the kidney transplantation. Our additional contribution to this field is the discovery of H2S-derived polysulfides, which exist in the brain and activate transient receptor potential ankyrin-1 (TRPA1) channels 300 times more potently than H2S. TRPA1 channels mediate the sensory transduction and respond to a variety of stimuli, including cold temperature, pungent compounds and environmental irritants, but its endogenous ligand has not been identified. The sulfane sulfur of polysulfides is reactive electrophile and readily transferred to a nucleophilic protein thiolate, to generate the protein persulfide (sulfhydration). The sulfhydration activity of polysulfides is much greater than H2S. The production of H2S and the physiological function of H2S and polysulfides will be discussed. PMID:24948219

Kimura, Hideo

2013-09-01

80

Silver Sulfide Cathode for Liquid Ammonia Batteries and Fuel Cells.  

National Technical Information Service (NTIS)

The patent application relates to the practical use of silver sulfide as a rechargeable cathode for batteries and fuel cells using ammonia electrolytes. The attractiveness of liquid ammonia electrolytes for batteries and fuel cells is largely due to the c...

M. H. Miles

1973-01-01

81

HSLA steels with improved hydrogen sulfide cracking resistance  

SciTech Connect

Both hydrogen-induced cracking (HIC) and sulfide-stress cracking (SSC) in sour environments are examined. The fundamental concepts of hydrogen trapping and a critical concentration (C /SUB k/ ) for hydrogen crack initiation are defined. The main crack initiation sites for HIC are inclusions (manganese sulfides and oxides). Sulfur content influences the C /SUB k/ parameters. Manganese sulfides become finer and more homogeneously distributed when sulfur content decreases. This favors HIC resistance. Below a critical sulfur content (S < 2 X 10/sup -3/ pct), HIC becomes negligible. The influences of calcium additions and microstructure are also discussed. In the SSC case influence of stress direction, microstructure, and metalloid (e.g., phosphorus) content are examined. It is then shown that good SSC resistance can be achieved, whatever the direction of the applied stress, using a proper combination of parameters that include both chemical and microstructural factors.

Pressouyre, G.M.; Blondeau, R.; Cadiou, L.

1984-06-01

82

Hydrogen sulfide-mediated myocardial pre- and post-conditioning  

PubMed Central

Coronary artery disease is a major cause of morbidity and mortality in the Western world. Acute myocardial infarction, resulting from coronary artery atherosclerosis, is a serious and often fatal consequence of coronary artery disease, resulting in cell death in the myocardium. Pre- and post-conditioning of the myocardium are two treatment strategies that reduce the amount of cell death significantly. Hydrogen sulfide has recently been identified as a potent cardioprotective signaling molecule, which is a highly effective pre- and post-conditioning agent. The cardioprotective signaling pathways involved in hydrogen sulfide-based pre- and post-conditioning will be explored in this article.

Predmore, Benjamin L; Lefer, David J

2011-01-01

83

A generalized correlation for the Peng-Robinson interaction coefficients for paraffin?hydrogen sulfide binary systems  

Microsoft Academic Search

A review of the literature revealed a paucity of data for the vapor-liquid equilibrium of systems containing hydrogen sulfide and paraffin hydrocarbons. In order to estimate the vapor-liquid equilibrium of systems for which no data exist, a correlation of the interaction parameter for the Peng-Robinson equation of state is provided.

John J Carroll; Alan E Mather

1995-01-01

84

Removing hydrogen sulfide from geothermal gases: hypochlorite process reduces hydrogen sulfide emissions to acceptable levels. NTIS tech note  

SciTech Connect

This citation summarizes a one-page announcement of technology available for utilization. A hypochlorite process has been proposed as an alternative to other methods for the removal of hydrogen sulfide from the exhaust gases of geothermal powerplants. An electrolytically-generated sodium hypochlorite solution converts the hydrogen sulfide to water, salt, and sulfur. The hypochlorite process appears to be less expensive than competing processes for most of the cases studied. ...FOR ADDITIONAL INFORMATION: Detailed information about the technology described may be obtained by ordering the NTIS report, order number: DOE/ER/1092-T7, price code: PC A03.

Not Available

1981-10-01

85

New inhibitors of hydrogen sulfide corrosion for gas-turbine oils  

Microsoft Academic Search

Along with the development of deposits of natural gas containing hydrogen sulfide, it has become extremely urgent to provide corrosion protection for the equipment in gas pumping stations and gas processing plants. In the presence of moisture and hydrogen sulfide, the rates of overall and chemical corrosion are several times higher; and hydrogen embrittlement and sulfide cracking of steel may

V. A. Trofimov; V. G. Spirkin; T. O. Ablyazova; A. A. Bocharov

1997-01-01

86

Anode materials for a hydrogen sulfide solid oxide fuel cell  

SciTech Connect

The performance of a solid oxide fuel cell utilizing hydrogen sulfide as a fuel was studied with CoS{sub 1.035}, WS{sub 2}, and Li{sub 2}S/CoS{sub 1.035} anode materials. The electrolyte was yttria-stabilized zirconia with a thickness ranging from 40--500 {micro}m. Power densities of over 400 mW/cm{sup 2} were obtained with the Li/Co sulfide based material and gas analysis demonstrated hydrogen sulfide destruction levels in excess of 75%. Cell performance was noted to degrade slightly over time, which can be attributed to air leaks within the experimental system or delamination of the electrodes.

Yates, C.; Winnick, J.

1999-08-01

87

Hydrogen evolution from water through metal sulfide reactions  

NASA Astrophysics Data System (ADS)

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

Saha, Arjun; Raghavachari, Krishnan

2013-11-01

88

Process for purifying an aqueous, hydrogen sulfide-scrubbing solution  

SciTech Connect

This patent describes a process for purifying an aqueous hydrogen sulfide-scrubbing solution containing a water-soluble vanadium component and a water-soluble organic compound, the scrubbing solution being capable of absorbing hydrogen sulfide and converting the hydrogen sulfide into elemental sulfur. The process comprises: forming a slurry by mixing the scrubbing solution with particles of a spent solid catalyst containing molybdenum and aluminum and a basic aqueous solution; contacting the slurry with an oxygen-containing gas under conditions such that the molybdenum in the catalyst is dissolved and oxidized to molybdate while the aluminum remains substantially in the form of a solid residue; separating the aqueous solution formed from the solid residue; contacting the aqueous solution with hydrogen sulfide under conditions such that the molybdenum in the solution is precipitated, thereby forming an aqueous solution having a reduced concentration of molybdenum; contacting the aqueous solution having a reduced concentration of molybdenum with a base under conditions such that the vanadium in the solution is precipitated, thereby forming an aqueous solution having a reduced concentration of vanadium and molybdenum; and recovering the aqueous solution having a reduced concentration of vanadium and molybdenum as wastewater.

Koepke, J.W.; Delaney, D.D.

1989-11-28

89

Novel Hydrogen Sulfide Sensors for Portable Monitors, Phase 2.  

National Technical Information Service (NTIS)

The primary objective of this SBIR Phase II project was to design, develop, and demonstrate a better sensor technology for detecting the presence of hydrogen sulfide (H2S), a particularly hazardous gas species. Because of the potential for adverse health ...

S. Williams

2006-01-01

90

Novel Hydrogen Sulfide Sensors for Portable Monitors, Phase 1.  

National Technical Information Service (NTIS)

During this SBIR Phase I project, Nanomaterials Research (NRLLC) successfully demonstrated a new type of sensor device for detecting hydrogen sulfide (H2S). This gas is extremely toxic at low concentrations, and workplace exposure is common in a number of...

C. J. Kostelecky D. J. Deininger E. J. Benstock K. Womer M. W. Hooker S. A. Hooker S. S. Williams

2002-01-01

91

HEALTH ASSESSMENT DOCUMENT FOR HYDROGEN SULFIDE, REVIEW DRAFT  

EPA Science Inventory

Hydrogen sulfide is a highly toxic gas which is immediately lethal in concentrations greater than 2000 ppm. The toxic end-point is due to anoxia to brain and heart tissues which results from its interaction with the celluar enzyme cytochrome oxidase. Inhibition of the enzyme halt...

92

Kinetics and mechanism of hydrogen sulfide oxidation in sea water  

SciTech Connect

This article provides a comprehensive chemical investigation on the oxidation of acid rain-transported hydrogen sulfides in sea water and on the environmental consequences of their oxidation products. Biochemical and microbiological mechanisms are discussed in detail. Implications and effects for the world's oceans in general are discussed and special emphasis is given to the Black Sea.

Leonov, A.V.; Aizatullin, T.A.

1987-11-01

93

Health Assessment Document for Hydrogen Sulfide, Review Draft.  

National Technical Information Service (NTIS)

Hydrogen sulfide is a highly toxic gas which is immediately lethal in concentrations greater than 2000 ppm. The toxic end-point is due to anoxia to brain and heart tissues which results from its interaction with the celluar enzyme cytochrome oxidase. Inhi...

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

1986-01-01

94

Composition and method for removing hydrogen sulfide from gas streams  

Microsoft Academic Search

This patent describes a composition for oxidizing hydrogen sulfide to form elemental sulfur in the composition and for effecting settling of the elemental sulfur from the composition. It comprises an aqueous solution containing chelated water soluble polyvalent metal ions and at least one water soluble nonionic surfactant having an HLB of from 8 to 10. This patent also describes a

1991-01-01

95

REMOVING HYDROGEN SULFIDE FROM SOUR CRUDES IN THE FIELD  

Microsoft Academic Search

A chemical treating process is described that reduces dissolved hydrogen sulfide gas in crude oil to a concentration of less than 50 ppm. Such a process sytem is readily available for field installation with a minimum of surveillance being required. The treating takes place between the emulsion-separator equipment and production tankage. An aqueous ammonium hydroxide solutions is used to convert

Wolf J. R; T. C. McLean

1979-01-01

96

The Solubility of Hydrogen Sulfide in Acetonitrile at 25°C  

Microsoft Academic Search

The solubility of hydrogen sulfide in acetonitrile at 25°C has been determined both gravimetrically and titrimetrically to be 0. 528 M. The effects of the presence of water and an electrolyte (LiClO4) on this parameter are reported.

John F. Evans; Henry N. Blount

1974-01-01

97

DETERMINATION OF HYDROGEN SULFIDE IN REFINERY FUEL GASES  

EPA Science Inventory

Several widely employed test methods for the iodimetric measurement of hydrogen sulfide in refinery fuel gases are shown to suffer from serious thiol interferences. An absorbing solution consisting of 0.16 M cadmium sulfate/sulfuric acid at pH 3.0 is shown to be effective for the...

98

Nitrite as an antidote for acute hydrogen sulfide intoxication  

SciTech Connect

The detoxification of hydrogen sulfide (H/sub 2/S) by a heme catalyzed oxidation was examined as part of an on-going study of H/sub 2/S toxicity. Interlocking O/sub 2/ absorption and sulfide depletion data indicate that both oxyhemoglobin and methemoglobin are effective catalytic agents. Although the latter is more efficacious, the life time of excess sulfide in the presence of oxygen and either of the above is of the order of minutes. It has also been established that the formation of methemoglobin following nitrite administration occurs preferentially under oxygen poor conditions. Under an atmospheric or oxygen enriched environment, which favors sulfide depletion, the nitrite retards sulfide oxidation. Thus nitrite as an antidote for acute H/sub 2/S intoxication can only be effective within the first few minutes after the exposure, at which time resuscitation and/or ventilation of the victim is likely to produce conditions in which the nitrite actually slows sulfide removal.

Beck, J.F.; Bradbury, C.M.; Connors, A.J.; Donini, J.C.

1981-11-01

99

Solubility and permeation of hydrogen sulfide in lipid membranes.  

PubMed

Hydrogen sulfide (H(2)S) is mainly known for its toxicity but has recently been shown to be produced endogenously in mammalian tissues and to be associated with physiological regulatory functions. To better understand the role of biomembranes in modulating its biological distribution and effects; we measured the partition coefficient of H(2)S in models of biological membranes. The partition coefficients were found to be 2.1±0.2, 1.9±0.5 and 2.0±0.6 in n-octanol, hexane and dilauroylphosphatidylcholine liposome membranes relative to water, respectively (25°C). This two-fold higher concentration of H(2)S in the membrane translates into a rapid membrane permeability, P(m)?=?3 cm s(-1). We used a mathematical model in three dimensions to gain insight into the diffusion of total sulfide in tissues. This model shows that the sphere of action of sulfide produced by a single cell expands to involve more than 200 neighboring cells, and that the resistance imposed by lipid membranes has a significant effect on the diffusional spread of sulfide at pH 7.4, increasing local concentrations. These results support the role of hydrogen sulfide as a paracrine signaling molecule and reveal advantageous pharmacokinetic properties for its therapeutic applications. PMID:22509322

Cuevasanta, Ernesto; Denicola, Ana; Alvarez, Beatriz; Möller, Matías N

2012-01-01

100

Liquid-Hydrogen Polygeneration System  

NASA Technical Reports Server (NTRS)

Polygeneration system uses existing technology in integrated process to produce liquid hydrogen space-vehicle propellant and secondary products as gaseous nitrogen, electrical energy, and thermal energy. Makes commercial launch services economical. Lowers expected cost of liquid hydrogen by utilizing relatively cheap coal feedstocks and by reducing electrical costs associated with producing liquid hydrogen.

Minderman, P.; Gutkowski, G.; Manfredi, L.; King, J.; Howard, F.

1986-01-01

101

Biology and therapeutic potential of hydrogen sulfide and hydrogen sulfide-releasing chimeras  

PubMed Central

Hydrogen sulfide, H2S, is a colorless gas with a strong odor that until recently was only considered to be a toxic environmental pollutant with little or no physiological significance. However, the past few years have demonstrated its role in many biological systems and it is becoming increasingly clear that H2S is likely to join nitric oxide (NO) and carbon monoxide (CO) as a major player in mammalian biology. In this review, we have provided an overview of the chemistry and biology of H2S and have summarized the chemistry and biological activity of some natural and synthetic H2S-donating compounds. The naturally occurring compounds discussed include, garlic, sulforaphane, erucin, and iberin. The synthetic H2S donors reviewed include, GYY4137; cysteine analogs; S-propyl cysteine, S-allyl cysteine, S-propargyl cysteine, and N-acetyl cysteine. Dithiolethione and its NSAID and other chimeras such as, L-DOPA, sildenafil, aspirin, diclofenac, naproxen, ibuprofen, indomethacin, and mesalamine have also been reviewed in detail. The newly reported NOSH-aspirin that releases both NO and H2S has also been discussed.

Kashfi, Khosrow; Olson, Kenneth R.

2012-01-01

102

Liquid Hydrogen: Target, Detector  

NASA Astrophysics Data System (ADS)

In 1952 D. Glaser demonstrated that a radioactive source's radiation could boil 135°C superheated-diethyl ether in a 3-mm Ø glass vessel and recorded bubble track growth on high-speed film in a 2-cm3 chamber. This Bubble Chamber (BC) promised improved particle track time and spatial resolution and cycling rate. Hildebrand and Nagle, U of Chicago, reported Liquid Hydrogen minimum ionizing particle boiling in August 1953. John Wood created the 3.7-cm Ø Liquid Hydrogen BC at LBL in January 1954. By 1959 the Lawrence Berkley Laboratory (LBL) Alvarez group's ``72-inch'' BC had tracks in liquid hydrogen. Within 10 years bubble chamber volumes increased by a factor of a million and spread to every laboratory with a substantial high-energy physics program. The BC, particle accelerators and special separated particle beams created a new era of High Energy Physics (HEP) experimentation. The BC became the largest most complex cryogenic installation at the world's HEP laboratories for decades. The invention and worldwide development, deployment and characteristics of these cryogenic dynamic target/detectors and related hydrogen targets are described.

Mulholland, G. T.; Harigel, G. G.

2004-06-01

103

Hydrogen Permeation of Carbon Steel in Weak Alkaline Solution Containing Hydrogen Sulfide and Cyanide Ion  

Microsoft Academic Search

The hydrogen permeation behavior of carbon steel (CS) was investigated electrochemically in weak alkaline solutions containing hydrogen sulfide (HâS) with various cyanide ion (CN⁻) concentrations under open-circuit conditions. Anodic and cathodic polarization behaviors of CS also were investigated under the same environmental conditions. Little hydrogen content (Câ) was detected in alkaline solutions without CN⁻. However, when a small amount of

K. Yamakawa; R. Nishimura

1999-01-01

104

A FRET enzyme-based probe for monitoring hydrogen sulfide.  

PubMed

Fluorescently labeled cobalt peptide deformylase (Co-PDF) can be efficiently used as a fluorescence-resonance-energy-transfer-based sensing device for hydrogen sulfide (H(2)S). The proof of concept of our sensor system is substantiated by spectroscopic, structural, and theoretical results. Monohydrogen sulfide coordination to Co-PDF and Ni-PDF was verified by X-ray crystallography. Density functional theory calculations were performed to gain insight into the characteristics of the coordination adduct between H(2)S and the cobalt cofactor in Co-PDF. PMID:23072298

Strianese, Maria; Palm, Gottfried J; Milione, Stefano; Kühl, Olaf; Hinrichs, Winfried; Pellecchia, Claudio

2012-11-01

105

Hydrogen sulfide and resolution of acute inflammation: A comparative study utilizing a novel fluorescent probe  

PubMed Central

Hydrogen sulfide is an essential gasotransmitter associated with numerous pathologies. We assert that hydrogen sulfide plays an important role in regulating macrophage function in response to subsequent inflammatory stimuli, promoting clearance of leukocyte infiltrate and reducing TNF-? levels in vivo following zymosan-challenge. We describe two distinct methods of measuring leukocyte hydrogen sulfide synthesis; methylene blue formation following zinc acetate capture and a novel fluorescent sulfidefluor probe. Comparison of these methods, using pharmacological tools, revealed they were complimentary in vitro and in vivo. We demonstrate the application of sulfidefluor probe to spectrofluorimetry, flow cytometry and whole animal imaging, to monitor the regulation of hydrogen sulfide synthesis in vivo during dynamic inflammatory processes. Both methodologies revealed that granulocyte infiltration negatively affects hydrogen sulfide synthesis. Our report offers an insight into the profile of hydrogen sulfide synthesis during inflammation and highlight opportunities raised by the development of novel fluorescent hydrogen sulfide probes.

Dufton, Neil; Natividad, Jane; Verdu, Elena F.; Wallace, John L.

2012-01-01

106

Hydrogen sulfide and resolution of acute inflammation: A comparative study utilizing a novel fluorescent probe.  

PubMed

Hydrogen sulfide is an essential gasotransmitter associated with numerous pathologies. We assert that hydrogen sulfide plays an important role in regulating macrophage function in response to subsequent inflammatory stimuli, promoting clearance of leukocyte infiltrate and reducing TNF-? levels in vivo following zymosan-challenge. We describe two distinct methods of measuring leukocyte hydrogen sulfide synthesis; methylene blue formation following zinc acetate capture and a novel fluorescent sulfidefluor probe. Comparison of these methods, using pharmacological tools, revealed they were complimentary in vitro and in vivo. We demonstrate the application of sulfidefluor probe to spectrofluorimetry, flow cytometry and whole animal imaging, to monitor the regulation of hydrogen sulfide synthesis in vivo during dynamic inflammatory processes. Both methodologies revealed that granulocyte infiltration negatively affects hydrogen sulfide synthesis. Our report offers an insight into the profile of hydrogen sulfide synthesis during inflammation and highlight opportunities raised by the development of novel fluorescent hydrogen sulfide probes. PMID:22787557

Dufton, Neil; Natividad, Jane; Verdu, Elena F; Wallace, John L

2012-01-01

107

Surface analysis of inhibitor films formed in hydrogen sulfide medium  

SciTech Connect

Steel samples exposed to a 5% sodium chloride solution containing 0.5% acetic acid saturated with hydrogen sulfide, with and without imidazole as an inhibitor, were analyzed by X-ray photoelectron spectroscopy and secondary ion mass spectrometry. The metal surface was covered initially by a layer of iron sulfide or oxide. This layer, in turn, was covered by layers in which Fe was bonded to bisulfide and C{sub 3}H{sub 4}N{sub 2} groups. Corrosion protection probably resulted from the iron sulfide or oxide formed on the metal which was prevented from going into solution and recrystallization by the thin upper layer containing C{sub 3}H{sub 4}N{sub 2}.

Sastri, V.S.; Elboujdaini, M.; Brown, J.R. [CANMET, Ottawa, Ontario (Canada); Perumareddi, J.R. [Florida Atlantic Univ., Boca Raton, FL (United States). Chemistry Dept.

1996-06-01

108

Possibility of hydrogen sulfide induced iron toxicity of the rice plant  

Microsoft Academic Search

Hydrogen sulfide causes abnormalities of the rice plant (1), such as “akiochi” believed to be a result of hydrogen sulfide toxicity. The disease occurs on soils low in active iron and in which sulfide, produced by the reduction of sulfate under flooded conditions, remains in the soil solution at a considerable concentration because there is insufficient iron to form the

A. Tanaka; Ranjit P. Mulleriyawa; T. Yasu

1968-01-01

109

MODELING OF SYNGAS REACTIONS AND HYDROGEN GENERATION OVER SULFIDES  

SciTech Connect

The objective of the research is to analyze pathways of reactions of hydrogen with oxides of carbon over sulfides, and to predict which characteristics of the sulfide catalyst (nature of metal, defect structure) give rise to the lowest barriers toward oxygenated hydrocarbon product. Reversal of these pathways entails the generation of hydrogen, which is also proposed for study. During this study, adsorption reactions of H atoms and H{sub 2} molecules with MoS{sub 2}, both in molecular and solid form, have been modeled using high-level density functional theory. The relative stabilities of pure MoS{sub 2} edges were calculated and small clusters exhibiting properties of the edges were modeled. The results were finalized and published in the journal ''Surface Science''. Hydrogen adsorption energies on both the edges and the clusters were calculated, and the thermodynamics of hydrogen adsorption on both systems were evaluated. The adsorption locations and vibrational frequencies were also determined. These additional results were published in a second paper in ''Surface Science''. Most recently, the bonding and effect of alkali and transition metal ions was investigated on the MoS{sub 2} clusters. Potassium atoms bind to the clusters and increase the binding of hydrogen to the clusters while reducing the activation barriers for hydrogen adsorption. Silver attaches to the Mo7S14 cluster and donates its odd electron to the nearby Mo atoms and should have a similar effect to hydrogen as potassium does.

Kamil Klier; Jeffery A. Spirko; Michael L. Neiman

2004-10-01

110

Transition metal sulfide hydrogen evolution catalysts for hydrobromic acid electrolysis.  

PubMed

Mixed metal sulfides containing combinations of W, Fe, Mo, Ni, and Ru were synthesized and screened for activity and stability for the hydrogen evolution reaction (HER) in aqueous hydrobromic acid (HBr). Co- and Ni-substituted RuS(2) were identified as potentially active HER electrocatalysts by high-throughput screening (HTS), and the specific compositions Co(0.4)Ru(0.6)S(2) and Ni(0.6)Ru(0.4)S(2) were identified by optimization. Hydrogen evolution activity of Co(0.4)Ru(0.6)S(2) in HBr is greater than RuS(2) or CoS(2) and comparable to Pt and commercial Rh(x)S(y). Structural and morphological characterizations of the Co-substituted RuS(2) suggest that the nanoparticulate solids are a homogeneous solid solution with a pyrite crystal structure. No phase separation is detected for Co substitutions below 30% by X-ray diffraction. In 0.5 M HBr electrolyte, the Co-Ru electrode material synthesized with 30% Co rapidly lost approximately 34% of the initial loading of Co; thereafter, it was observed to exhibit stable activity for HER with no further loss of Co. Density functional theory calculations indicate that the S(2)(2-) sites are the most important for HER and the presence of Co influences the S(2)(2-) sites such that the hydrogen binding energy at sufficiently high hydrogen coverage is decreased compared to ruthenium sulfide. Although showing high HER activity in a flow cell, the reverse reaction of hydrogen oxidation is slow on the RuS(2) catalysts tested when compared to platinum and rhodium sulfide, leaving rhodium sulfide as the only suitable tested material for a regenerative HBr cell due its stability compared to platinum. PMID:23205859

Ivanovskaya, Anna; Singh, Nirala; Liu, Ru-Fen; Kreutzer, Haley; Baltrusaitis, Jonas; Nguyen, Trung Van; Metiu, Horia; McFarland, Eric

2013-01-01

111

State-of-the-art hydrogen sulfide control for geothermal energy systems: 1979  

SciTech Connect

Existing state-of-the-art technologies for removal of hydrogen sulfide are discussed along with a comparative assessment of their efficiencies, reliabilities and costs. Other related topics include the characteristics of vapor-dominated and liquid-dominated resources, energy conversion systems, and the sources of hydrogen sulfide emissions. It is indicated that upstream control technologies are preferred over downsteam technologies primarily because upstream removal of hydrogen sulfide inherently controls all downstream emissions including steam-stacking. Two upstream processes for vapor-dominated resources appear promising; the copper sulfate (EIC) process, and the steam converter (Coury) process combined with an off-gas abatement system such as a Stretford unit. For liquid-dominated systems that produce steam, the process where the non-condensible gases are scrubbed with spent geothermal fluid appears to be promising. An efficient downstream technology is the Stretford process for non-condensible gas removal. In this case, partitioning in the surface condenser will determine the overall abatement efficiency. Recommendations for future environmental control technology programs are included.

Stephens, F.B.; Hill, J.H.; Phelps, P.L. Jr.

1980-03-01

112

Modeling of Syngas Reactions and Hydrogen Generation Over Sulfides  

SciTech Connect

The objective of the research is to analyze pathways of reactions of hydrogen with oxides of carbon over sulfides, and to predict which characteristics of the sulfide catalyst (nature of metal, defect structure) give rise to the lowest barriers toward oxygenated hydrocarbon product. Reversal of these pathways entails the generation of hydrogen, which is also proposed for study. In this second year of study, high-level density functional theory was used to model the edge defect of MoS{sub 2} both with and without H atoms and H{sub 2} molecules absorbed on those edges. The structures and stabilities of the pure MoS{sub 2} edges were finalized and published. Several MoS{sub 2} cluster models were examined to provide insight into the behavior of the more complex edges. With that knowledge, the adsorption locations, energies, and vibrational frequencies of H adsorption were determined.

Kamil Klier; Jeffery A. Spirko; Michael L. Neiman

2003-09-17

113

Health assessment document for hydrogen sulfide: review draft  

SciTech Connect

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

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

1986-08-01

114

Solubility of hydrogen sulfide in aqueous solutions of the single salts sodium sulfate, ammonium sulfate, sodium chloride, and ammonium chloride at temperatures from 313 to 393 K and total pressures up to 10 MPa  

Microsoft Academic Search

New experimental results for the solubility of hydrogen sulfide in aqueous solutions of the single salts sodium sulfate, ammonium sulfate, sodium chloride, and ammonium chloride at temperatures from 313 to 393 K and total pressures up to 10 MPa are reported. As in the salt-free system, a second-hydrogen sulfide-rich--liquid phase is observed at high hydrogen sulfide concentrations. A model to

Jianzhong Xia; A. P. S. Kamps; Bernd Rumpf; Gerd Maurer

2000-01-01

115

Solubility of hydrogen sulfide in aqueous solutions of the single salts sodium sulfate, ammonium sulfate, sodium chloride, and ammonium chloride at temperatures from 313 to 393 K and total pressures up to 10 MPa  

SciTech Connect

New experimental results for the solubility of hydrogen sulfide in aqueous solutions of the single salts sodium sulfate, ammonium sulfate, sodium chloride, and ammonium chloride at temperatures from 313 to 393 K and total pressures up to 10 MPa are reported. As in the salt-free system, a second-hydrogen sulfide-rich--liquid phase is observed at high hydrogen sulfide concentrations. A model to describe the phase equilibrium is presented. Calculations are compared to the new experimental data.

Xia, J.; Kamps, A.P.S.; Rumpf, B.; Maurer, G.

2000-04-01

116

Process for the removal of hydrogen sulfide from gaseous streams by catalytic oxidation of hydrogen sulfide to sulfur while inhibiting the formation of sulfur oxides  

Microsoft Academic Search

A process is provided for removing hydrogen sulfide and alkyl mercaptans from gaseous streams. The hydrogen sulfide is oxidized catalytically to sulfur, substantially without formation of sulfur oxides, in the presence of a metal chelate catalyst solution and a soluble alkali metal or alkaline earth metal or ammonium or amine salt of an acid having a pK within the range

Meuly

1977-01-01

117

MET17 and Hydrogen Sulfide Formation in Saccharomyces cerevisiae  

Microsoft Academic Search

Commercial isolates of Saccharomyces cerevisiae differ in the production of hydrogen sulfide (H2S) during fermentation, which has been attributed to variation in the ability to incorporate reduced sulfur into organic compounds. We transformed two commercial strains (UCD522 and UCD713) with a plasmid overexpressing the MET17 gene, which encodes the bifunctional O-acetylserine\\/O-acetylhomoserine sulfhydrylase (OAS\\/OAH SHLase), to test the hypothesis that the

APOSTOLOS SPIROPOULOS; LINDA F. BISSON

2000-01-01

118

Hydrogen evolution from water through metal sulfide reactions  

SciTech Connect

Transition metal sulfides play an important catalytic role in many chemical reactions. In this work, we have conducted a careful computational study of the structures, electronic states, and reactivity of metal sulfide cluster anions M{sub 2}S{sub X}{sup ?} (M = Mo and W, X = 4–6) using density functional theory. Detailed structural analysis shows that these metal sulfide anions have ground state isomers with two bridging sulfide bonds, notably different in some cases from the corresponding oxides with the same stoichiometry. The chemical reactivity of these metal sulfide anions with water has also been carried out. After a thorough search on the reactive potential energy surface, we propose several competitive, energetically favorable, reaction pathways that lead to the evolution of hydrogen. Selectivity in the initial water addition and subsequent hydrogen migration are found to be the key steps in all the proposed reaction channels. Initial adsorption of water is most favored involving a terminal metal sulfur bond in Mo{sub 2}S{sub 4}{sup ?} isomers whereas the most preferred orientation for water addition involves a bridging metal sulfur bond in the case of W{sub 2}S{sub 4}{sup ?} and M{sub 2}S{sub 5}{sup ?} isomers. In all the lowest energy H{sub 2} elimination steps, the interacting hydrogen atoms involve a metal hydride and a metal hydroxide (or thiol) group. We have also observed a higher energy reaction channel where the interacting hydrogen atoms in the H{sub 2} elimination step involve a thiol (–SH) and a hydroxyl (–OH) group. For all the reaction pathways, the Mo sulfide reactions involve a higher barrier than the corresponding W analogues. We observe for both metals that reactions of M{sub 2}S{sub 4}{sup ?} and M{sub 2}S{sub 5}{sup ?} clusters with water to liberate H{sub 2} are exothermic and involve modest free energy barriers. However, the reaction of water with M{sub 2}S{sub 6}{sup ?} is highly endothermic with a considerable barrier due to saturation of the local bonding environment.

Saha, Arjun; Raghavachari, Krishnan [Department of Chemistry, Indiana University, Bloomington, Indiana 47405 (United States)] [Department of Chemistry, Indiana University, Bloomington, Indiana 47405 (United States)

2013-11-28

119

Thermodynamic modeling of hydrogen sulfide solubility in ionic liquids using modified SAFT-VR and PC-SAFT equations of state  

Microsoft Academic Search

Equations of state based on the statistical associating fluid theory for potentials of variable range (SAFT-VR) and the perturbed chain statistical associating fluid theory (PC-SAFT) have been used to model the PVT behavior of ionic liquids and the solubility of H2S in six imidazolium-based ionic liquids. The studied systems included [bmim][PF6], [hmim][PF6], [bmim][BF4], [hmim][BF4], [bmim][NTF2] and [hmim][NTF2] at various temperatures

Mahboubeh Rahmati-Rostami; Bahman Behzadi; Cyrus Ghotbi

2011-01-01

120

Hydrogen sulfide inhibits macrophage-derived foam cell formation.  

PubMed

Recent evidence indicates that hydrogen sulfide (H(2)S) exerts an antiatherogenic effect, but the mechanism is unclear. Formation of macrophage-derived foam cells is a crucial event in the development of atherosclerosis. Thus, we explore the effect of H(2)S on the formation of macrophage-derived foam cells. Incubation of monocyte-derived macrophages with oxidized LDL (oxLDL) alone caused significant increases both in intracellular lipids revealed by Oil-red O staining and in intracellular total cholesterol (TC) and esterified cholesterol (EC) concentrations assessed by high-performance liquid chromatography. Sodium hydrosulfide (NaHS, an H(2)S donor) remarkably abrogated oxLDL-induced intracellular lipid accumulation, and attenuated TC and EC concentrations and EC/TC ratio, whereas dl-propargylglycine (PPG) (a H(2)S-generating enzyme cystathionine gamma lyase inhibitor) exacerbated lipid accumulation and augmented TC and EC concentrations and EC/TC ratio. Incubation of 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI)-oxLDL led to lipoprotein binding and uptake of macrophages, which was blunted by NaHS, but enhanced by PPG. Furthermore, OxLDL markedly induced CD36, scavenger receptor A (SR-A) and acyl-coenzyme A:cholesterol acyltransferase-1 (ACAT-1) expressions in macrophages, which was suppressed by NaHS (50-200 ?mol/L). Finally, the down-regulations of TC and EC concentrations as well as CD36 and ACAT-1 expressions by NaHS were suppressed by glibenclamide, a K(ATP) channel blocker, but facilitated by PD98059, an extracellular signal-regulated kinases 1 and 2 (ERK1/2) inhibitor. These results suggested that H(2)S inhibits foam cell formation by down-regulating CD36, SR-A and ACAT1 expressions via the K(ATP)/ERK1/2 pathway in human monocyte-derived macrophages. PMID:21321313

Zhao, Zhan-Zhi; Wang, Zuo; Li, Guo-Hua; Wang, Ren; Tan, Jian-Miao; Cao, Xuan; Suo, Rong; Jiang, Zhi-Sheng

2011-02-01

121

Decomposition of Hydrogen Sulfide in a Dielectric-Barrier Discharge  

NASA Astrophysics Data System (ADS)

Hydrogen sulfide is not only an unwanted compound that has to be efficiently removed in many industrial processes but it is also an abundant source for potentially cheap hydrogen. Many natural gas reserves contain large amounts of hydrogen sulfide mixed with the natural gas. In the past plasma processing of H_2S has been extensively investigated in low-pressure microwave discharges. Some laboratory experiments have also been performed in dielectric-barrier discharges (DBDs). We report on complete decomposition of atmospheric pressure H_2S into hydrogen and solid sulfur in a small laboratory through-flow DBD reactor made of two coaxial cylindrical quartz tubes with external coaxial electrodes. The discharge is confined to an annular gap of 2 mm radial width and 110 mm length. It can be observed through a wire mesh electrode. In some of the experiments helium was used as a carrier gas. The concentrations of H2 and H_2S were measured with a gas chromatograph equipped with a PoraPlot Q column and a molecular sieve column. The dielectric-barrier discharge was operated in the frequency range 20-25 kHz or in the range 180-215 kHz. The amount of hydrogen generated was related to the amount of energy put into the discharge.

Kogelschatz, Ulrich; Killer, Eric; Eliasson, Baldur

1999-10-01

122

C-H\\ctdot X (X = S, P) hydrogen bonding: The complexes of halothane with dimethyl sulfide and trimethylphosphine  

NASA Astrophysics Data System (ADS)

The formation of C-H⋯S and C-H⋯P hydrogen bonded complexes of halothane, CHBrClCF3, with dimethyl sulfide(-d6) and trimethylphosphine(-d9) have been studied in solutions of liquid krypton using infrared and Raman spectroscopy. In the 1:1 complexes, the halothane CH stretching mode is found to be red-shifted by 43 cm-1 in the dimethyl sulfide complex, and by 63 cm-1 in the trimethylphosphine complex. The complexation enthalpies were derived and amount to -10.7(2) and -11.2(2) kJ mol-1 for the respective complexes. The experiments were supported by ab initio calculations and Monte Carlo simulations. The obtained data for the C-H⋯S and C-H⋯P hydrogen bonds is compared to that of corresponding C-H⋯O and C-H⋯N hydrogen bonds.

Michielsen, B.; Verlackt, C.; van der Veken, B. J.; Herrebout, W. A.

2012-09-01

123

Identification of Genes Affecting Hydrogen Sulfide Formation in Saccharomyces cerevisiae?  

PubMed Central

A screen of the Saccharomyces cerevisiae deletion strain set was performed to identify genes affecting hydrogen sulfide (H2S) production. Mutants were screened using two assays: colony color on BiGGY agar, which detects the basal level of sulfite reductase activity, and production of H2S in a synthetic juice medium using lead acetate detection of free sulfide in the headspace. A total of 88 mutants produced darker colony colors than the parental strain, and 4 produced colonies significantly lighter in color. There was no correlation between the appearance of a dark colony color on BiGGY agar and H2S production in synthetic juice media. Sixteen null mutations were identified as leading to the production of increased levels of H2S in synthetic juice using the headspace analysis assay. All 16 mutants also produced H2S in actual juices. Five of these genes encode proteins involved in sulfur containing amino acid or precursor biosynthesis and are directly associated with the sulfate assimilation pathway. The remaining genes encode proteins involved in a variety of cellular activities, including cell membrane integrity, cell energy regulation and balance, or other metabolic functions. The levels of hydrogen sulfide production of each of the 16 strains varied in response to nutritional conditions. In most cases, creation of multiple deletions of the 16 mutations in the same strain did not lead to a further increase in H2S production, instead often resulting in decreased levels.

Linderholm, Angela L.; Findleton, Carrie L.; Kumar, Gagandeep; Hong, Yeun; Bisson, Linda F.

2008-01-01

124

Utilization of Hyperbaric Oxygen Therapy and Induced Hypothermia After Hydrogen Sulfide Exposure  

PubMed Central

Hydrogen sulfide is a toxic gas produced as a byproduct of organic waste and many industrial processes. Hydrogen sulfide exposure symptoms may vary from mild (dizziness, headaches, nausea) to severe lactic acidosis via its inhibition of oxidative phosphorylation, leading to cardiac arrhythmias and death. Treatment is generally supportive. We report the case of a patient presenting with cardiac arrest secondary to hydrogen sulfide exposure treated with both hyperbaric oxygen therapy and therapeutic hypothermia with great improvement in neurologic function.

Asif, Mir J.; Exline, Matthew C.

2013-01-01

125

Hydrogen sulfide-mediated cardioprotection: mechanisms and therapeutic potential.  

PubMed

H2S (hydrogen sulfide), viewed with dread for more than 300 years, is rapidly becoming a ubiquitously present and physiologically relevant signalling molecule. Knowledge of the production and metabolism of H2S has spurred interest in delineating its functions both in physiology and pathophysiology of disease. Although its role in blood pressure regulation and interaction with NO is controversial, H2S, through its anti-apoptotic, anti-inflammatory and antioxidant effects, has demonstrated significant cardioprotection. As a result, a number of sulfide-donor drugs, including garlic-derived polysulfides, are currently being designed and investigated for the treatment of cardiovascular conditions, specifically myocardial ischaemic disease. However, huge gaps remain in our knowledge about this gasotransmitter. Only by additional studies will we understand more about the role of this intriguing molecule in the treatment of cardiovascular disease. PMID:21126235

Lavu, Madhav; Bhushan, Shashi; Lefer, David J

2011-03-01

126

Solubility in the system NaâSâOâ - NaâCOâ - HâO and a crystallization method for separating the components of the absorbent solution used for removing hydrogen sulfide from gases by the quinhydrone method  

Microsoft Academic Search

Removal of hydrogen sulfide from gases is becoming of increasing importance not only as a social factor (protection of the environment) but also as a promising method of obtaining elemental sulfur. One of the cheapest and technologically most convenient sources of by-product sulfur is natural gas. Development of a new liquid-phase oxidation method for removing hydrogen sulfide from natural gas

V. T. Yavorskii; V. I. Semenova; Y. A. Kalymon

1981-01-01

127

Micellar-mediated extractive spectrophotometric determination of hydrogen sulfide/sulfide through Prussian Blue reaction: application to environmental samples.  

PubMed

A sensitive surfactant-mediated extractive spectrophotometric method has been developed, based on the reaction of ferric iron with sulfide to form ferrous iron and its subsequent reaction with ferricyanide to form Prussian Blue, to quantify trace levels of hydrogen sulfide/sulfide in environmental samples. The method obeys Beer's law in the concentration range 2-10 microg of sulfide in 25 mL of aqueous phase with molar absorptivity (epsilon) of 3.92 x 10(4) L mol(-1) cm(-1). The colored species has been extracted into isoamyl acetate in the presence of a cationic surfactant i.e. cetylpyridinium chloride, to enhance the sensitivity of the method with epsilon value 5.2 x 10(4) L mol(-1) cm(-1). The relative standard deviation has been found to be 0.69% for 10 determinations at 4 microg of sulfide and the limit of detection was 0.009 microg mL(-1). The interference from common anions and cations has been studied. The proposed method has been applied to the determination of residual hydrogen sulfide in the laboratory fume hood as well as ambient atmospheric hydrogen sulfide in the vicinity of open sewer lines after fixing the analyte in ionic form using suitable trapping medium. PMID:20065592

Pandurangappa, Malingappa; Samrat, Devaramani

2010-01-01

128

Effect of the silicon concentration in iron in the reaction between iron and hydrogen sulfide  

SciTech Connect

The authors investigate the metallurgical effects of silicon on the corrosion resistance of an iron base-silicon alloy in contact with hydrogen sulfide for purposes of assessing the alloy as a candidate refinery material for the refining of petroleum rich in hydrogen sulfide content. The mechanisms of corrosion and sulfidation of the alloy and diffusion of the sulfur at different silicon quantities are examined by a tracer technique using sulfur 35.

Rogov, A.I.; Petrova, E.F.; Kozlenkov, E.M.; Shvartsman, L.A.

1987-04-01

129

Exposure to Hydrogen Sulfide, Mercaptans and Sulfur Dioxide in Pulp Industry  

Microsoft Academic Search

An hygienic survey for hydrogen sulfide, methyl mercaptan and its derivatives and sulfur dioxide in kraft mills and in sulfite mills revealed concentrations varying from 0 to 20?ppm hydrogen sulfide, 0 to 15?ppm methyl mercaptan and comparable amounts of dimethyl sulfide with dimethyl disulfide up to 1.5?ppm. The greatest emissions were detected at chip chutes and evaporation vacuum pumps. Batch

J. KANGAS; P. JÄPPINEN; H. SAVOLAINEN

1984-01-01

130

Gas chromatographic analysis for hydrogen sulfide, organic sulfides, mercaptans, and carbon dioxide in hydrocarbon matrices using an electrolytic conductivity detector  

Microsoft Academic Search

American Natural Service Co. explains that when used in conjunction with gas chromatography, an electrolytic conductivity detector can satisfactorily determine the amounts of hydrogen sulfide, mercaptans, organic sulfides, and carbon dioxide in natural gas that is rich (over 1%) in heavy hydrocarbons (Câ-Câ). The detector method has a definite advantage over the commonly used flame-photometric-detector technique in that it produces

R. G. Schiller; R. B. Bronsky

1977-01-01

131

Modeling of Syngas Reactions and Hydrogen Generation Over Sulfides  

SciTech Connect

The objective of the research is to analyze pathways of reactions of hydrogen with oxides of carbon over sulfides, and to predict which characteristics of the sulfide catalyst (nature of metal, defect structure) give rise to the lowest barriers toward oxygenated hydrocarbon product. Reversal of these pathways entails the generation of hydrogen, which is also proposed for study. In this first year of study, adsorption reactions of H atoms and H{sub 2} molecules with MoS{sub 2}, both in molecular and solid form, have been modeled using high-level density functional theory. The geometries and strengths of the adsorption sites are described and the methods used in the study are described. An exposed MO{sup IV} species modeled as a bent MoS{sub 2} molecule is capable of homopolar dissociative chemisorption of H{sub 2} into a dihydride S{sub 2}MoH{sub 2}. Among the periodic edge structures of hexagonal MoS{sub 2}, the (1{bar 2}11) edge is most stable but still capable of dissociating H{sub 2}, while the basal plane (0001) is not. A challenging task of theoretically accounting for weak bonding of MoS{sub 2} sheets across the Van der Waals gap has been addressed, resulting in a weak attraction of 0.028 eV/MoS{sub 2} unit, compared to the experimental value of 0.013 eV/MoS{sub 2} unit.

Kamil Klier; Jeffery A. Spirko; Michael L. Neiman

2002-09-17

132

The novel neuromodulator hydrogen sulfide: an endogenous peroxynitrite 'scavenger'?  

PubMed

Hydrogen sulfide (H2S) is a well-known cytotoxic gas. Recently it has been shown to stimulate N-methyl-D-aspartate (NMDA) receptors to enhance long-term potentiation suggesting a novel neuromodulatory role in vivo. Endogenous levels of H2S in the brain are reported to range between 10 and 160 microm. Considerably lower H2S levels are reported in the brains of Alzheimer's disease (AD) patients, where levels of brain protein nitration (probably mediated by peroxynitrite) are markedly increased. Activation of NMDA receptors leads to intracellular tyrosine nitration by peroxynitrite. Because H2S and peroxynitrite are important mediators in brain function and disease, we investigated the effects of the H2S 'donor', sodium hydrogen sulfide (NaSH) on peroxynitrite-mediated damage to biomolecules and to cultured human SH-SY5Y cells. H2S significantly inhibited peroxynitrite-mediated tyrosine nitration and inactivation of alpha1-antiproteinase to a similar extent to reduced glutathione at each concentration tested (30-250 microm). H2S also inhibited peroxynitrite-induced cytotoxicity, intracellular protein nitration and protein oxidation in human neuroblastoma SH-SY5Y cells. These data suggest that H2S has the potential to act as an inhibitor of peroxynitrite-mediated processes in vivo and that the potential antioxidant action of H2S deserves further study, given that extracellular GSH levels in the brain are very low. PMID:15255956

Whiteman, Matthew; Armstrong, Jeffrey S; Chu, Siew Hwa; Jia-Ling, Siau; Wong, Boon-Seng; Cheung, Nam Sang; Halliwell, Barry; Moore, Philip K

2004-08-01

133

Health Effects from Chronic Low-Level Exposure to Hydrogen Sulfide  

Microsoft Academic Search

The acute toxic effects of hydrogen sulfide have been known for decades. However, studies investigating the adverse health effects from chronic, low-level exposure to this chemical are limited. In this study, the authors compared symptoms of adverse health effects, reported by residents of two communities exposed mainly to chronic, low-levels of industrial sources of hydrogen sulfide, to health effects reported

Marvin S. Legator; Chantele R. Singleton; Debra L. Morris; Donna L. Philips

2001-01-01

134

30 CFR 550.215 - What hydrogen sulfide (H2S) information must accompany the EP?  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false What hydrogen sulfide (H2S) information must accompany... Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT, DEPARTMENT OF THE INTERIOR...Exploration Plans (ep) § 550.215 What hydrogen sulfide (H2 S) information must...

2013-07-01

135

Use of AERMOD to determine a hydrogen sulfide emission factor for swine operations by inverse modeling  

Microsoft Academic Search

This study was conducted to determine both optimal settings applied to the plume dispersion model, AERMOD, and a scalable emission factor for accurately determining the spatial distribution of hydrogen sulfide concentrations in the vicinity of swine concentrated animal feeding operations (CAFOs). These operations emit hydrogen sulfide from both housing structures and waste lagoons. With ambient measurements made at 4 stations

Patrick T. O’Shaughnessy; Ralph Altmaier

2011-01-01

136

Process for removing hydrogen sulfide from gases particularly coal pyrolysis gases  

Microsoft Academic Search

Hydrogen sulfide is first removed by ammoniacal liquor from coke oven gas in the bottom part of a gas scrubber. In the top part of the scrubber, two consecutively-arranged fine scrubbing stages remove hydrogen sulfide by treating the gases, in the upper stage, with a caustic soda solution or a caustic potash solution. Beneath the upper scrubbing stage is the

H. Ritter; E. T. Herpers

1985-01-01

137

The reduction of hexavalent uranium by hydrogen sulfide in aqueous solutions at increased temperatures and pressures  

Microsoft Academic Search

In connection with a study of the conditions of transport and deposition of uranium by hydrothermal solutions in the formation of uranium deposits, experiments were conducted earlier on the reduction of hexavalent uranium with hydrogen sulfide at temperatures up to 300~ in sulfate and carbonate solutions [I]. However, the amount of hydrogen sulfide in these experiments was not particularly monitored;

R. P. Rafal'skii; B. S. Osipov

1971-01-01

138

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

EPA Science Inventory

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

139

Removal of hydrogen sulfide with on site generated sulfite from geothermal steam  

Microsoft Academic Search

This patent describes a continuous process for abating hydrogen sulfide in geothermal steam. It comprises: condensing the geothermal steam with an aqueous solution of sulfites, essentially free of peroxide and polyvalent metal chelate, and containing a cationic polymeric catalyst to convert up to about one-third of the hydrogen sulfide to soluble thiosulfate and to obtain a non-condensable gas stream of

S. A. Bedell; L. H. Kirby

1990-01-01

140

Physical solubility of hydrogen sulfide and carbon dioxide in alkanolamine solutions  

Microsoft Academic Search

The study was undertaken to develop a method that would make direct measurements of acid gases, hydrogen sulfide and carbon dioxide, physical solubilities in aqueous alkanolamine solutions possible. Hydrogen sulfide and carbon dioxide physical solubilities in 20, 35, and 50% by weight diethanolamine aqueous solutions were measured. The solubility measurements were made at acid gas partial pressure up to 1000

Abu-Arabi

1988-01-01

141

Removal of hydrogen sulfide from fluid streams with minimum production of solids  

Microsoft Academic Search

Fluid streams containing hydrogen sulfide from a steam turbine or from a sour gas stream are contacted with an aqueous solution of a polyvalent metal chelate and an oxidizing agent whereby the hydrogen sulfide is converted to free sulfur and then to soluble sulfur compounds. The metal chelate is reduced to a lower oxidation state metal chelate and reduced metal

G. C. Jeffrey; L. A. Cooper; S. S. Whipple

1984-01-01

142

40 CFR 60.648 - Optional procedure for measuring hydrogen sulfide in acid gas-Tutwiler Procedure. 1  

Code of Federal Regulations, 2013 CFR

...for measuring hydrogen sulfide in acid gas-Tutwiler Procedure. 1 60.648...Performance for SO2 Emissions From Onshore Natural Gas Processing for Which Construction...measuring hydrogen sulfide in acid gasâTutwiler Procedure. 1 1...

2013-07-01

143

40 CFR 60.5408 - What is an optional procedure for measuring hydrogen sulfide in acid gas-Tutwiler Procedure?  

Code of Federal Regulations, 2013 CFR

...for measuring hydrogen sulfide in acid gas-Tutwiler Procedure? 60.5408...Standards of Performance for Crude Oil and Natural Gas Production, Transmission and Distribution...for measuring hydrogen sulfide in acid gasâTutwiler Procedure? The...

2013-07-01

144

Factors controlling the reactivity of hydrogen sulfide with hemeproteins†  

PubMed Central

Hemoglobin I (HbI) from the clam Lucina pectinata is an intriguing hemeprotein that binds and transports H2S to sulfide-oxidizing chemoautotrophic bacteria to maintain a symbiotic relationship and to protect the mollusk from H2S toxicity. Single point mutations at E7, B10 and E11 positions were introduced in the HbI heme pocket to define the reactivity of sulfide with hemeproteins. The functional and structural properties of mutant and wild type recombinant proteins were first evaluated using the well-known ferrous CO and O2 derivatives. The effects of these mutations on the ferric environment were then studied in the metaquo and hydrogen sulfide derivatives. The results obtained with the ferrous HbI mutants show that all the E7 substitutions and the PheB10Tyr mutation influence directly CO and O2 binding and stability while the B10 and E11 substitutions induce distal structural rearrangements that affect ligand entry and escape indirectly. For the metaquo-GlnE7His, PheB10Val, PheB10Leu and the E11 variants, two individual distal structures are suggested, one of which is associated with H-bonding interactions between the E7 residues and the bound water. Similar H-bonding interactions are invoked for these HbI-H2S mutant derivatives and the rHbI, altering in turn sulfide reactivity within these protein samples. This is evident in the resonance Raman spectra of these HbI-H2S complexes, which show reduction of heme iron as judged by the appearance of the ?4 oxidation state marker at 1356 cm?1, indicative of heme-FeII species. This reduction process depends strongly on distal mutations showing faster reduction for those HbI mutants exhibiting strongest H-bonding interactions. Overall, the results presented here show that: a. H2S association is regulated by steric constraints; b. H2S release is controlled by two competing reactions involving simple sulfide dissociation and heme reduction; c. at high H2S concentrations, reduction of the ferric center dominates; d. reduction of the heme is also enhanced in those HbI mutants having polar distal environments.

Pietri, Ruth; Lewis, Ariel; Leon, Ruth G.; Casabona, Gullermina; Kiger, Laurent; Yeh, Syun-Ru; Fernandez-Alberti, Sebastian; Marden, Michael C.; Cadilla, Carmen L.; Lopez-Garriga, Juan

2009-01-01

145

Airborne sulfur trace species intercomparison campaign: Sulfur dioxide, dimethylsulfide, hydrogen sulfide, carbon disulfide, and carbonyl sulfide  

NASA Technical Reports Server (NTRS)

Results from an airborne intercomparison of techniques to measure tropospheric levels of sulfur trace gases are presented. The intercomparison was part of the NASA Global Tropospheric Experiment (GTE) and was conducted during the summer of 1989. The intercomparisons were conducted on the Wallops Electra aircraft during flights from Wallops Island, Virginia, and Natal, Brazil. Sulfur measurements intercompared included sulfur dioxide (SO2), dimethylsulfide (DMS), hydrogen sulfide (H2S), carbon disulfide (CS2), and carbonyl sulfide (OCS). Measurement techniques ranged from filter collection systems with post-flight analyses to mass spectrometer and gas chromatograph systems employing various methods for measuring and identifying the sulfur gases during flight. Sampling schedules for the techniques ranged from integrated collections over periods as long as 50 minutes to one- to three-minute samples every ten or fifteen minutes. Several of the techniques provided measurements of more than one sulfur gas. Instruments employing different detection principles were involved in each of the sulfur intercomparisons. Also included in the intercomparison measurement scenario were a host of supporting measurements (i.e., ozone, nitrogen oxides, carbon monoxide, total sulfur, aerosols, etc.) for purposes of: (1) interpreting results (i.e., correlation of any noted instrument disagreement with the chemical composition of the measurement environment); and (2) providing supporting chemical data to meet CITE-3 science objectives of studying ozone/sulfur photochemistry, diurnal cycles, etc. The results of the intercomparison study are briefly discussed.

Gregory, Gerald L.; Hoell, James M., Jr.; Davis, Douglas D.

1991-01-01

146

High temperature hydrogen sulfide removal with tin oxide  

SciTech Connect

The system is based on the absorption of hydrogen sulfide (H{sub 2}S) by stannic (tin) oxide. Two sorbents are required, the first sorbent is tin oxide and the second sorbent is a zinc oxide based material (i.e., zinc ferrite or zinc titanate) which is regenerated by air producing SO{sub 2}. TDA`s process carries out a modified Claus reaction to reduce the SO{sub 2} from the second sorbent generation to elemental sulfur. In this case the sulfided stannic oxide forms stannous sulfide (SnS) which reduces the SO{sub 2}. The absorption by SnO{sub 2} could remove over 90% of the H{sub 2}S from typical coal gas streams, but we use zinc ferrite (or zinc titanate), (a) to reduce H{sub 2}S to less than 20 ppM and (b) as a source of SO{sub 2} in regeneration. Due to stoichiometry of regeneration we want to remove half of the H{sub 2}S by SnO{sub 2} and the remainder by the second sorbent. The reactions with stannic oxide minimize the heat released during H{sub 2}S removal and regeneration. The absorption by SnO{sub 2} is slightly endothermic and cools the gas stream by less that 5{degrees}F (2.8{degrees}C) during absorption. Regeneration with SO{sub 2} is exothermic but releases only 11% of the heat that is liberated in regenerating the ZnO. For a nominal 6.5:1 steam to air the regeneration of ZnO increases the temperature by {approx_equal}400{degrees}F. The regeneration of SnO{sub 2} increases the temperature by less than 50{degrees}F (28{degrees}C) in the same gas flow.

Karpuk, M.E.; Copeland, R.J.; Feinberg, D.; Wickham, D.; Windecker, B.; Yu, J.

1993-09-01

147

Fluorometric field instrument for continuous measurement of atmospheric hydrogen sulfide.  

PubMed

A sensitive (limit of detection approximately <100 pptv at S/N = 3), fully automated, portable (32 x 25 x 38 cm, 4.5 kg) instrument has been designed for continuous field measurement of atmospheric hydrogen sulfide. Air is sampled by a PTFE membrane-based diffusion scrubber and collected into an aLkaline fluorescein mercuric acetate (FMA) solution flowing under a controlled and constant pneumatic pressure. The collected sulfide quenches the fluorescence that is measured with a miniature blue LED photodiode-based fluorescence detector. Acquisition and interpretation of signal and all flow control are carried out via a mininotebook personal computer (PC) using custom software written in HP-VEE. The instrument provides for self-calibration and zero functions using an on-board permeation tube enclosed in a thermostated block, at any preprogrammed desired interval. During sampling, the computed H2S concentration is stored every 2 min. The complete system, including the PC, is operated in the field by a 12-V marine battery. The system was field tested near oil field operations in West Texas and showed good correlations with a concurrently operated lead acetate tape-based commercial sampler, with a response speed and time resolution much better than that of the latter instrument. PMID:11774912

Toda, K; Dasgupta, P K; Li, J; Tarver, G A; Zarus, G M

2001-12-01

148

Thermal decomposition of hydrogen sulfide at low concentrations  

SciTech Connect

The initial step of the thermal decomposition of hydrogen sulfide has been investigated by the direct measurement of the time-dependent H atom concentration behind reflected shock waves in the temperature range 1965/sup 0/K less than or equal to T less than or equal to 2560/sup 0/K, using the atomic resonance absorption spectrophotometry (ARAS). The experiments have been performed in mixtures of Ar with small concentrations of H/sub 2/S (25 to 200 ppM), at total pressures of about 1.8 to 2.0 bar, corresponding to concentrations of the order of (5 to 7) x 10/sup 18/ molecules cm/sup -3/.

Roth, P.; Loehr, R.; Barner, U.

1982-03-01

149

Hydrogen sulfide chemical biology: pathophysiological roles and detection.  

PubMed

Hydrogen sulfide (H2S) is the most recent endogenous gasotransmitter that has been reported to serve many physiological and pathological functions in different tissues. Studies over the past decade have revealed that H2S can be synthesized through numerous pathways and its bioavailability regulated through its conversion into different biochemical forms. H2S exerts its biological effects in various manners including redox regulation of protein and small molecular weight thiols, polysulfides, thiosulfate/sulfite, iron-sulfur cluster proteins, and anti-oxidant properties that affect multiple cellular and molecular responses. However, precise measurement of H2S bioavailability and its associated biochemical and pathophysiological roles remains less well understood. In this review, we discuss recent understanding of H2S chemical biology, its relationship to tissue pathophysiological responses and possible therapeutic uses. PMID:23850632

Kolluru, Gopi K; Shen, Xinggui; Bir, Shyamal C; Kevil, Christopher G

2013-11-30

150

Endogenous hydrogen sulfide is involved in the pathogenesis of atherosclerosis  

SciTech Connect

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

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

2010-05-28

151

Sulfur as a signaling nutrient through hydrogen sulfide.  

PubMed

Hydrogen sulfide (H2S) has emerged as an important signaling molecule with beneficial effects on various cellular processes affecting, for example, cardiovascular and neurological functions. The physiological importance of H2S is motivating efforts to develop strategies for modulating its levels. However, advancement in the field of H2S-based therapeutics is hampered by fundamental gaps in our knowledge of how H2S is regulated, its mechanism of action, and its molecular targets. This review provides an overview of sulfur metabolism; describes recent progress that has shed light on the mechanism of H2S as a signaling molecule; and examines nutritional regulation of sulfur metabolism, which pertains to health and disease. PMID:25033061

Kabil, Omer; Vitvitsky, Victor; Banerjee, Ruma

2014-07-17

152

Hydrogen sulfide as a potential biomarker of asthma.  

PubMed

Hydrogen sulfide (H2S), a gas characterized by the odor of rotten eggs, is produced by many cells in the airways and lungs, and may regulate physiologic and pathophysiologic processes. It plays a role in cellular signaling, and represents the third gasotransmitter after nitric oxide and carbon monoxide. Endogenous and exogenous H?S have anti-inflammatory and anti-proliferative effects, with inhibitory effects in models of lung inflammation and fibrosis. Under certain conditions, H?S may also be proinflammatory. It is generally a vasodilator and relaxant of airway and vascular smooth muscle cells. It acts as a reducing agent, being able to scavenge superoxide and peroxynitrite. H?S is detectable in serum and in sputum supernatants with raised levels observed in asthmatics. The sputum levels correlated inversely with lung function. H?S may play a role in the pathogenesis of asthma. PMID:24308655

Chung, Kian F

2014-02-01

153

The metallization and superconductivity of dense hydrogen sulfide.  

PubMed

Hydrogen sulfide (H2S) is a prototype molecular system and a sister molecule of water (H2O). The phase diagram of solid H2S at high pressures remains largely unexplored arising from the challenges in dealing with the pressure-induced weakening of S-H bond and larger atomic core difference between H and S. Metallization is yet achieved for H2O, but it was observed for H2S above 96 GPa. However, the metallic structure of H2S remains elusive, greatly impeding the understanding of its metallicity and the potential superconductivity. We have performed an extensive structural study on solid H2S at pressure ranges of 10-200 GPa through an unbiased structure prediction method based on particle swarm optimization algorithm. Besides the findings of candidate structures for nonmetallic phases IV and V, we are able to establish stable metallic structures violating an earlier proposal of elemental decomposition into sulfur and hydrogen [R. Rousseau, M. Boero, M. Bernasconi, M. Parrinello, and K. Terakura, Phys. Rev. Lett. 85, 1254 (2000)]. Our study unravels a superconductive potential of metallic H2S with an estimated maximal transition temperature of ?80 K at 160 GPa, higher than those predicted for most archetypal hydrogen-containing compounds (e.g., SiH4, GeH4, etc.). PMID:24811660

Li, Yinwei; Hao, Jian; Liu, Hanyu; Li, Yanling; Ma, Yanming

2014-05-01

154

The metallization and superconductivity of dense hydrogen sulfide  

NASA Astrophysics Data System (ADS)

Hydrogen sulfide (H2S) is a prototype molecular system and a sister molecule of water (H2O). The phase diagram of solid H2S at high pressures remains largely unexplored arising from the challenges in dealing with the pressure-induced weakening of S-H bond and larger atomic core difference between H and S. Metallization is yet achieved for H2O, but it was observed for H2S above 96 GPa. However, the metallic structure of H2S remains elusive, greatly impeding the understanding of its metallicity and the potential superconductivity. We have performed an extensive structural study on solid H2S at pressure ranges of 10-200 GPa through an unbiased structure prediction method based on particle swarm optimization algorithm. Besides the findings of candidate structures for nonmetallic phases IV and V, we are able to establish stable metallic structures violating an earlier proposal of elemental decomposition into sulfur and hydrogen [R. Rousseau, M. Boero, M. Bernasconi, M. Parrinello, and K. Terakura, Phys. Rev. Lett. 85, 1254 (2000)]. Our study unravels a superconductive potential of metallic H2S with an estimated maximal transition temperature of ˜80 K at 160 GPa, higher than those predicted for most archetypal hydrogen-containing compounds (e.g., SiH4, GeH4, etc.).

Li, Yinwei; Hao, Jian; Liu, Hanyu; Li, Yanling; Ma, Yanming

2014-05-01

155

Kinetics of ? hydrogen abstractions from thiols, sulfides and thiocarbonyl compounds.  

PubMed

Hydrogen abstraction reactions involving organosulfur compounds play an important role in many industrial, biological and atmospheric processes. Despite their chemical relevance, little is known about their kinetics. In this work a group additivity model is developed that allows predicting the Arrhenius parameters for abstraction reactions of ? hydrogen atoms from thiols, alkyl sulfides, alkyl disulfides and thiocarbonyl compounds by carbon-centered radicals at temperatures ranging from 300 to 1500 K. Rate coefficients for 102 hydrogen abstractions were obtained using conventional transition state theory within the high-pressure limit. Electronic barriers were calculated using the CBS-QB3 method and the rate coefficients were corrected for tunneling and hindered rotation about the transitional bond. Group additivity values for 46 groups are determined. To account for resonance and hyperconjugative stabilization in the transition state, 8 resonance corrections were fitted to a set of 32 reactions. The developed group additivity scheme was validated using a test set containing an additional 30 reactions. The group additivity scheme succeeds in reproducing the rate coefficients on average within a factor of 2.4 at 300 K and 1.4 at 1000 K. Mean absolute deviations of the Arrhenius parameters amount to, respectively, 2.5 kJ mol(-1) for E(a) and 0.13 for log A, both at 300 and 1000 K. This work hence illustrates that the recently developed group additivity methods for Arrhenius parameters extrapolate successfully to hetero-element containing compounds. PMID:22854881

Vandeputte, Aäron G; Sabbe, Maarten K; Reyniers, Marie-Françoise; Marin, Guy B

2012-10-01

156

Selective Catalytic Oxidation of Hydrogen Sulfide--Systems Analysis for IGCC Applications  

SciTech Connect

Selective catalytic oxidation of hydrogen sulfide (SCOHS) has been evaluated conceptually for IGCC applications, and the theoretical limits of reaction performance, process performance, and economic potential in IGCC have been estimated. Syngas conditions that have high partial pressures of total sulfur result in substantial liquid sulfur retention within the catalyst bed, with relatively complex processing being required. Applications that have much lower total sulfur partial pressure in the process gas might permit SCOHS operation under conditions where little liquid sulfur is retained in the catalyst, reducing the processing complexity and possibly improving the desulfurization performance. The results from our recent IGCC process evaluations using the SCOHS technology and conventional syngas cleaning are presented, and alternative SCOHS process configurations and applications that provide greater performance and cost potential are identified.

Newby, R.A.; Keairns, D.L.; Alvin, M.A.

2006-09-01

157

Hydrogenation processes using carbon-containing molybdenum and tungsten sulfide catalysts  

SciTech Connect

Sulfur and nitrogen-containing hydrocarbon feeds are upgraded by contacting said feed, at elevated temperature and in the presence of hydrogen, with a catalyst comprising a carbon-containing sulfide of a catalytic metal selected from the group consisting of tungsten, molybdenum and mixture thereof. In a preferred embodiment, these catalysts are promoted with certain transition metal sulfides such as cobalt sulfide. The catalyst may be preformed or formed in-situ in the feed or from catalyst precursor salts.

Pecorado, T. A.; Chianelli, R. R.

1985-07-09

158

Metal?organic frameworks for the storage and delivery of biologically active hydrogen sulfide  

SciTech Connect

Hydrogen sulfide is an extremely toxic gas that is also of great interest for biological applications when delivered in the correct amount and at the desired rate. Here we show that the highly porous metal-organic frameworks with the CPO-27 structure can bind the hydrogen sulfide relatively strongly, allowing the storage of the gas for at least several months. Delivered gas is biologically active in preliminary vasodilation studies of porcine arteries, and the structure of the hydrogen sulfide molecules inside the framework has been elucidated using a combination of powder X-ray diffraction and pair distribution function analysis.

Allan, Phoebe K.; Wheatley, Paul S.; Aldous, David; Mohideen, M. Infas; Tang, Chiu; Hriljac, Joseph A.; Megson, Ian L.; Chapman, Karena W.; De Weireld, Guy; Vaesen, Sebastian; Morris, Russell E. (St Andrews)

2012-04-02

159

Acid production from sulfide minerals using hydrogen peroxide weathering  

Microsoft Academic Search

Sulfide mineral weathering is a major source of acid generation in mining environments. Oxidation and hydrolysis reactions in soil and geologic material under earth surface conditions causes weathering of reduced sulfide minerals resulting in liberation of weathering products including acid. Pyrite and marcasite are minerals common in mine environments that cause acid generation. Many other sulfide minerals are present in

Stuart R Jennings; Douglas J Dollhopf; William P Inskeep

2000-01-01

160

Reduced graphene oxide based silver sulfide hybrid films formed at a liquid/liquid interface  

NASA Astrophysics Data System (ADS)

Free-standing, ultra-thin films of silver sulfide and reduced graphene oxide (RGO) based silver sulfide hybrids are prepared at a liquid/liquid interface employing in situ chemical reaction strategy. Ag2S and RGO-Ag2S hybrid films are characterized by various techniques such as UV-visible and photo luminescence spectroscopy, X-ray diffraction and scanning electron microscopy. The morphology of hybrid films consists of Ag2S nanocrystals on RGO surface while Ag2S films contains branched network of dendritic structures. RGO-Ag2S exhibit interesting optical and electrical properties. The hybrid films absorb in the region 500-650 nm and show emission in the red region. A higher conductance is observed for the hybrid films arising from the RGO component. This simple low cost method can be extended to prepare other RGO based metal sulfides.

Bramhaiah, K.; John, Neena S.

2014-04-01

161

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

ERIC Educational Resources Information Center

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…

Robles, E. G.

162

Nanoporous metal enhanced catalytic activities of amorphous molybdenum sulfide for high-efficiency hydrogen production.  

PubMed

We fabricated a robust electrocatalyst by chemically depositing an ultrathin layer of amorphous molybdenum sulfide on the internal surface of dealloyed nanoporous gold. The catalyst exhibits superior electrocatalysis toward hydrogen evolution reaction in both acidic and neutral media with 2-6 times improvement in catalytic activies compared to other molybdenum sulfide based materials. PMID:24554595

Ge, Xingbo; Chen, Luyang; Zhang, Ling; Wen, Yuren; Hirata, Akihiko; Chen, Mingwei

2014-05-21

163

No facilitator required for membrane transport of hydrogen sulfide  

PubMed Central

Hydrogen sulfide (H2S) has emerged as a new and important member in the group of gaseous signaling molecules. However, the molecular transport mechanism has not yet been identified. Because of structural similarities with H2O, it was hypothesized that aquaporins may facilitate H2S transport across cell membranes. We tested this hypothesis by reconstituting the archeal aquaporin AfAQP from sulfide reducing bacteria Archaeoglobus fulgidus into planar membranes and by monitoring the resulting facilitation of osmotic water flow and H2S flux. To measure H2O and H2S fluxes, respectively, sodium ion dilution and buffer acidification by proton release (H2S ? H+ + HS?) were recorded in the immediate membrane vicinity. Both sodium ion concentration and pH were measured by scanning ion-selective microelectrodes. A lower limit of lipid bilayer permeability to H2S, PM,H2S ? 0.5 ± 0.4 cm/s was calculated by numerically solving the complete system of differential reaction diffusion equations and fitting the theoretical pH distribution to experimental pH profiles. Even though reconstitution of AfAQP significantly increased water permeability through planar lipid bilayers, PM,H2S remained unchanged. These results indicate that lipid membranes may well act as a barrier to water transport although they do not oppose a significant resistance to H2S diffusion. The fact that cholesterol and sphingomyelin reconstitution did not turn these membranes into an H2S barrier indicates that H2S transport through epithelial barriers, endothelial barriers, and membrane rafts also occurs by simple diffusion and does not require facilitation by membrane channels.

Mathai, John C.; Missner, Andreas; Kugler, Philipp; Saparov, Sapar M.; Zeidel, Mark L.; Lee, John K.; Pohl, Peter

2009-01-01

164

Hydrogen sulfide does not increase resuscitability in a porcine model of prolonged cardiac arrest.  

PubMed

Treatment options to improve resuscitability and neurological prognosis after cardiac arrest (CA) are limited. Hydrogen sulfide has demonstrated remarkable improvements in outcomes in small animal models of severe hypoxia or hemorrhage. We investigated the influence of sodium sulfide (Na2S), a liquid hydrogen sulfide donor, on resuscitability, postresuscitation hemodynamics, and neurological performance in a porcine model of prolonged CA and cardiopulmonary resuscitation. Twenty-four male pigs were instrumented with arterial and pulmonary artery catheters before 10 min of CA was induced. During resuscitation, animals were randomized to receive either high-dose (1 mg/kg; n = 8) or low-dose (0.3 mg/kg; n = 8) Na2S (IK-1001; Ikaria, Clinton, NJ) or control (saline placebo; n = 8) i.v. injection and consecutive infusion. Cardiopulmonary resuscitation was performed for 6 min before defibrillation was attempted. Hemodynamic variables were taken at baseline and 10, 30, 60, 120, and 240 min after successful resuscitation. Neurological outcome was evaluated on 4 postoperative days before brains and hearts were harvested for histopathologic analysis. No differences in hemodynamic parameters were observed at baseline. Initial resuscitability was not improved by Na2S. Animals exposed to high- and low-dose Na2S showed significantly reduced cardiac output, heart rate, and pulmonary arterial pressure compared with control animals during the early postresuscitation period. Strikingly, two of the high-dose Na2S animals died during the postresuscitation period, whereas all other animals survived. High-dose Na2S significantly decreased microglial activation in striatal areas, although this did not translate into improved neurological outcome. Although animals receiving Na2S developed higher troponin T serum levels, these differences remained insignificant. In this investigation, Na2S did not improve resuscitability but significantly compromised postresuscitation hemodynamics. PMID:20090564

Derwall, Matthias; Westerkamp, Maren; Löwer, Céline; Deike-Glindemann, Jan; Schnorrenberger, Nora Katharina; Coburn, Mark; Nolte, Kay Wilhelm; Gaisa, Nadine; Weis, Joachim; Siepmann, Katharina; Häusler, Martin; Rossaint, Rolf; Fries, Michael

2010-08-01

165

Emersion in the Mangrove Forest Fish 'Rivulus marmoratus': A Unique Response to Hydrogen Sulfide.  

National Technical Information Service (NTIS)

The mangrove forest fish Rivulus marmoratus (Cyprinodontidae) has frequently been observed out of water, a phenomenon generally attributed to habitat drying. The authors tested the hypothesis that hydrogen sulfide, a substance characteristically found in ...

D. C. Abel C. C. Koenig W. P. Davis

1987-01-01

166

EMERSION IN THE MANGROVE FOREST FISH 'RIVULUS MARMORATUS': A UNIQUE RESPONSE TO HYDROGEN SULFIDE  

EPA Science Inventory

The mangrove forest fish Rivulus marmoratus (Cyprinodontidae) has frequently been observed out of water, a phenomenon generally attributed to habitat drying. The authors tested the hypothesis that hydrogen sulfide, a substance characteristically found in their environment, can se...

167

Hydrogen Sulfide Scavengers Market Assessment. Topical Report, June 16-December 15, 1995.  

National Technical Information Service (NTIS)

The report objective was to establish the dollar market size for removing low level concentrations of hydrogen sulfide from natural gas using commercially available scavengers, identify the key players, and determine significant trends in the industry. Th...

C. W. Houston

1996-01-01

168

The Cardioprotective Actions of Hydrogen Sulfide in Acute Myocardial Infarction and Heart Failure  

PubMed Central

It has now become universally accepted that hydrogen sulfide (H2S), previously considered only as a lethal toxin, has robust cytoprotective actions in multiple organ systems. The diverse signaling profile of H2S impacts multiple pathways to exert cytoprotective actions in a number of pathological states. This paper will review the recently described cardioprotective actions of hydrogen sulfide in both myocardial ischemia/reperfusion injury and congestive heart failure.

Polhemus, David J.; Calvert, John W.; Butler, Javed; Lefer, David J.

2014-01-01

169

HYDROGEN SULFIDE EMISSIONS FROM A MECHANICALLY-VENTILATED SWINE BUILDING DURING WARM WEATHER  

Microsoft Academic Search

Summary: Hydrogen sulfide (H2S) concentration in and emission from a new, grow-finish swine building with a deep pit was measured during three summer months. Hydrogen sulfide concentration, ventilation rate, temperature and pig number were continuously measured or recorded from June to September. Average daily mean (ADM) indoor H2S concentration was 173±21 ppb ranging from 38 to 536 ppb. The highest

Jiqin Ni; Albert J. Heber; Teng T. Lim; Ravikrishna Duggirala; Barry L. Haymore; Claude A. Diehl; Alan L. Sutton

1998-01-01

170

The removal of hydrogen sulfide in solution by ferric and alum water treatment residuals.  

PubMed

This work investigated the characteristics and mechanisms of hydrogen sulfide adsorption by ferric and alum water treatment residuals (FARs) in solution. The results indicated that FARs had a high hydrogen sulfide adsorption capacity. pH 7 rather than higher pH (e.g. pH 8-10) was favorable for hydrogen sulfide removal. The Yan model fitted the breakthrough curves better than the Thomas model under varied pH values and concentrations. The Brunauer-Emmett-Teller surface area and the total pore volume of the FARs decreased after the adsorption of hydrogen sulfide. In particular, the volume of pores with a radius of 3-5 nm decreased, while the volume of pores with a radius of 2 nm increased. Therefore, it was inferred that new adsorption sites were generated during the adsorption process. The pH of the FARs increased greatly after adsorption. Moreover, differential scanning calorimetry analysis indicated that elemental sulfur was present in the FARs, while the derivative thermal gravimetry curves indicated the presence of sulfuric acid and sulfurous acid. These results indicated that both oxidization and ligand exchange contribute to the removal of hydrogen sulfide by FARs. Under anaerobic conditions, the maximum amount of hydrogen sulfide released was approximately 0.026 mg g(-1), which was less than 0.19% of the total amount adsorbed by the FARs. The hydrogen sulfide that was released may be re-adsorbed by the FARs and transformed into more stable mineral forms. Therefore, FARs are an excellent adsorbent for hydrogen sulfide. PMID:22520971

Wang, Changhui; Pei, Yuansheng

2012-08-01

171

Mechanisms of action of hydrogen sulfide in relaxation of mouse distal colonic smooth muscle  

Microsoft Academic Search

Hydrogen sulfide (H2S) has been suggested as a gaseous neuromodulator in mammals. The aim of this study was to examine the influence of H2S on contractility in mouse distal colon. The effect of sodium hydrogen sulfide (NaHS; H2S donor) on prostaglandin F2? (PGF2?)-contracted circular muscle strips of mouse distal colon was investigated. In addition, tension and cytosolic calcium concentration ([Ca2+]cyt)

Ingeborg Dhaese; Inge Van Colen; Romain A. Lefebvre

2010-01-01

172

Solubility of hydrogen sulfide in water + monoethanolamine + 2-amino-2-methyl-1-propanol  

Microsoft Academic Search

Alkanolamine aqueous solutions are widely used in gas treating processes to remove acid gases, such as CO[sub 2] and H[sub 2]S, from natural, refinery, and synthesis gas streams. The solubilities of hydrogen sulfide in water (1) + monoethanolamine (2) + 2-amino-2-methyl-1-propanol (3) have been measured at 40, 60, 80, and 100 C and at partial pressures of hydrogen sulfide ranging

Meng-Hiu Li; Bei-Chia Chang

1994-01-01

173

Potential Biological Chemistry of Hydrogen Sulfide (H2S) with the Nitrogen Oxides  

PubMed Central

Hydrogen sulfide, an important gaseous signaling agent generated in numerous biological tissues, influences many physiological processes. This biological profile appears reminiscent of nitric oxide, another important endogenously synthesized gaseous signaling molecule. Hydrogen sulfide reacts with nitric oxide or oxidized forms of nitric oxide and nitric oxide donors in vitro to form species that display distinct biology compared to both hydrogen sulfide and NO. The products of these interesting reactions may include small molecule S-nitrosothiols or nitroxyl, the one-electron reduced form of nitric oxide. In addition, thionitrous acid or thionitrite, compounds structurally analogous to nitrous acid and nitrite may constitute a portion of the reaction products. Both the chemistry and biology of thionitrous acid and thionitrite, compared to nitric oxide or hydrogen sulfide, remain poorly defined. General mechanisms for the formation of S-nitrosothiols, nitroxyl and thionitrous acid based upon the ability of hydrogen sulfide to act as a nucleophile and reducing agent with reactive nitric oxide-based intermediates are proposed. Hydrogen sulfide reactivity appears extensive and could impact numerous areas of redox controlled biology and chemistry warranting more work in this exciting and developing area.

King, S. Bruce

2013-01-01

174

Supercooling of Liquid Hydrogen Microparticles  

NASA Astrophysics Data System (ADS)

Molecular hydrogen is a composite boson that is lighter than Helium-4; one of its superfluid phases is predicted for T< 5 K. Since hydrogen freezes at 14 K, the challenge is to supercool the liquid to low tempertures. We will discuss a generator of 20 K liquid hydrogen microparticles that is based on a piezoelectric actuator. The microparticles are injected in a cell kept at 4 K. This cell has optical windows and the microparticles are imaged and analyzed to study their shape dynamics. The microparticles can also be studied using infrared spectroscopy methods. Photoacoustic spectroscopy (PS) is very appropriate because it eliminates the elastic contribution to optical scattering. We will discuss the results obtained using PS. Supported by NSF.

Celestine, K.; Huber, T. E.

2002-03-01

175

Updated cost estimates of meeting geothermal hydrogen sulfide emission regulations  

SciTech Connect

A means of estimating the cost of hydrogen sulfide (H/sub 2/S) emission control was investigated. This study was designed to derive H/sub 2/S emission abatement cost functions and illustrate the cost of H/sub 2/S emission abatement at a hydrothermal site. Four tasks were undertaken: document the release of H/sub 2/S associated with geothermal development; review H/sub 2/S environmental standards; develop functional relationships that may be used to estimate the most cose-effective available H/sub 2/S abatement process; and use the cost functions to generate abatement cost estimates for a specific site. The conclusions and recommendations derived from the research are presented. The definition of the term impacts as used in this research is discussed and current estimates of the highest expected H/sub 2/S concentrations of in geothermal reservoirs are provided. Regulations governing H/sub 2/S emissions are reviewed and a review of H/sub 2/S control technology and a summary of the control cost functions are included. A case study is presented to illustrate H/sub 2/S abatement costs at the Baca KGRA in New Mexico.

Wells, K.D.; Currie, J.W.; Weakley, S.A.; Ballinger, M.Y.

1981-08-01

176

Microbial Regulation of Host Hydrogen Sulfide Bioavailability and Metabolism  

PubMed Central

Hydrogen sulfide (H2S), generated through various endogenous enzymatic and non-enzymatic pathways, is emerging as a regulator of physiological and pathological events throughout the body. Bacteria in the gastrointestinal tract also produce significant amounts of H2S that regulates microflora growth and virulence responses. However, the impact of the microbiota on host global H2S bioavailability and metabolism remain unknown. To address this question, we examined H2S bioavailability in its various forms (free, acid labile or bound sulfane sulfur), cystathionine gamma lyase (CSE) activity and cysteine levels in tissues from germ free versus conventionally housed mice. Free H2S levels were significantly reduced in plasma and gastrointestinal tissues of germ free mice. Bound sulfane sulfur levels were decreased by 50–80% in germ free mouse plasma, adipose and lung tissues. Tissue CSE activity was significantly reduced in many organs from germ free mice, whereas tissue cysteine levels were significantly elevated compared to conventional mice. These data reveal that the microbiota profoundly regulates systemic bioavailability and metabolism of H2S.

Shen, Xinggui; Carlstrom, Mattias; Borniquel, Sara; Jadert, Cecilia; Kevil, Christopher G; Lundberg, Jon

2014-01-01

177

An inhibitory enzyme electrode for hydrogen sulfide detection.  

PubMed

An enzymatic biosensing system has been developed to study the capability of ascorbate oxidase (AOx), EC (1.10.3.3), in hydrogen sulfide (H2S) detection, based on the inhibition of AOx activity. The immobilization parameters including glutaraldehyde (GA) concentration and pH were optimized using experimental design. The optimized values of GA concentration and pH were found to be 12.5% (w/w) and 7, respectively, where the enzymatic reaction reached the steady-state level within 55s. A linear relationship was observed between the decrease in the oxygen concentration and H2S concentration, where H2S concentration is in the range of 1-15mg/L. Moreover, to investigate the selectivity of the biosensor, a certain H2S concentration (9mg/L) was used against different ions. The results indicated that Fe(3+) and SO4(-2) ions had no significant (11% error) effect on the H2S detection. The operational stability of the biosensing system was determined in terms of response to H2S concentration, at optimal working conditions. The enzyme electrode could retain 73% of its original sensitivity after this period, which has made it possible for the system to measure H2S with concentrations as low as 0.5mg/L. PMID:25039053

Poor, Neda Zia Mottalebi; Baniasadi, Ladan; Omidi, Maysam; Amoabediny, Ghasem; Yazdian, Fatemeh; Attar, Hossein; Heydarzadeh, Ali; Zarami, Ashraf Sadat Hatamian; Sheikhha, Mohammad Hassan

2014-09-01

178

PROVISIONAL ADVISORY LEVELS (PALs) FOR HYDROGEN SULFIDE (H2S)  

SciTech Connect

Application of PAL protocols was performed for hydrogen sulfide (H2S) as experimental data permitted. The data base includes human experimental studies, worker exposure evaluations, as well as case studies on acute and repeated exposure. The data base of animal studies is substantial covering multiple species and addressing acute, repeated, and subchronic exposure scenarios. PAL estimates were approved by the Expert Consultation Panel for Provisional Advisory Levels in November 2006. No reliable data were found on oral exposure, making it impractical to estimate PALs for drinking water. Since H2S exists as a gas, partitioning to air is likely to occur with an environmental release. H2S inhalation PAL values for 24 hr exposure are: PAL 1 = 1.2 ppm; PAL 2 = 7.0 ppm; and PAL 3 = 27 ppm; the 30-d and 90-d inhalation exposure values are: PAL 1 = 0.85 ppm and PAL 2 = 3.0 ppm. PAL 3 values for 30-d and 90-d are not recommended due to insufficient data. Long-term data were insufficient to estimate 2-year inhalation PALs.

Marshall, Thomas C [ORNL; Dorman, David [College of Veterinary Medicine, North Carolina University; Gardner, Donald [Inhalation Toxicology Associates; Adeshina, Femi [U.S. Environmental Protection Agency; Ross, Robert Hord [ORNL

2009-01-01

179

Increasing prevalence of hydrogen sulfide negative Salmonella in retail meats.  

PubMed

Hydrogen sulfide (H2S) production is considered a typical characteristic of Salmonella and an important marker for Salmonella isolation. In this study, a total of 82 (26%) Salmonella strains were isolated from 113 chicken and 204 pork samples, within which 49 Salmonella strains were H2S positive and 33 were H2S negative. Salmonella enterica serovar Derby was most prevalent in both pork and chicken followed by S. Typhimurium in pork and S. Heidelberg in chicken. Salmonella isolated from pork exhibited a much higher H2S positive rate than those from chicken (68% versus 31%). The most prevalent H2S negative serotypes were S. Derby (40%) and S. Heidelberg (30%) in chicken, and S. Typhimurium (23%) and S. Enteritidis (23%) in pork. spvC, a plasmid-encoded virulence marker, was detected in 51% and 42% of the H2S positive and negative Salmonella respectively. The presence of the two most important serotypes, S. Enteritidis and S. Typhimurium, as well as a virulence plasmid in H2S negative Salmonella suggested that H2S negative Salmonella is also a significant public health concern. Such finding warrants the development of an improved method for effective coverage of H2S negative Salmonella. PMID:24929875

Lin, Dachuan; Yan, Meiying; Lin, Song; Chen, Sheng

2014-10-01

180

Hydrogen Sulfide Decomposition in Pulsed Corona Discharge Reactors  

NASA Astrophysics Data System (ADS)

Hydrogen sulfide (H2S) decomposition was carried out in each of four balance gases (Ar, He, N2 and H2) in a wire-in-tube pulsed corona discharge reactor. H2S conversion rates and H2S decomposition energy efficiencies depend on the balance gas and H2S concentrations. H2S conversion in monatomic balance gases, like Ar and He, is more efficient than in diatomic balance gases like N2 and H2. Low pulse forming capacitance, low charge voltage, and high pulse frequency operation produces the highest energy efficiency for H2S conversion at constant power. H2S conversion is more efficient in Ar-N2 gas mixture than in Ar or N2. These results can be explained by corona discharge observations, the electron attachment reactions of H2S and the proposed reaction mechanism of H2S dissociation. The results reveal the potential for energy efficient H2S decomposition in pulsed corona discharge reactors.

John, S.; Zhao, G. B.; Zhang, J. J.; Hamann, J. C.; Muknahallipatna, S. S.; Legowski, S.; Ackerman, J. F.; Argyle, M. D.

2008-10-01

181

A novel sorbent tube for ambient hydrogen sulfide determination.  

PubMed

A novel tubular device has been developed for hydrogen sulfide determination in air. Several substrates such as commercial silica gel and alumina TLC plates, silica gel powder, alumina, CaSO(4), CaCO(3), BaSO(4), MgO, chalk, alpha-cellulose and ethyl cellulose were tested as solid substrates. 30-70-mesh silica gel was finally employed in glass tubes of 4.0 mm internal diameter. Silica gel is treated with 0.5 M aqueous CdCl(2) solution, dried, filled into the glass tube and sample gas is passed through the device using nitrogen as the carrier gas where 70% relative humidity is employed. The analyte reacts with the solid substrate to form a luminescent spot whose length in the tube is measured and correlated to concentration. The flow rate was 68 ml min(-1). The analytical system is linear in the range of 0.2-1.3 ppm H(2)S for the specified conditions. The prepared devices are stable at least for 3 months prior to sampling; and after sampling, the luminescing spot is stable also at least for 3 months. PMID:18967360

Volkan, M; Eroglu, T; Eroglu, A E; Ataman, O Y; Mark, H B

1998-11-01

182

Role of Hydrogen Sulfide in the Pathology of Inflammation  

PubMed Central

Hydrogen sulfide (H2S) is a well-known toxic gas that is synthesized in the human body from the amino acids cystathionine, homocysteine, and cysteine by the action of at least two distinct enzymes: cystathionine-?-lyase and cystathionine-?-synthase. In the past few years, H2S has emerged as a novel and increasingly important biological mediator. Imbalances in H2S have also been shown to be associated with various disease conditions. However, defining the precise pathophysiology of H2S is proving to be a complex challenge. Recent research in our laboratory has shown H2S as a novel mediator of inflammation and work in several groups worldwide is currently focused on determining the role of H2S in inflammation. H2S has been implicated in different inflammatory conditions, such as acute pancreatitis, sepsis, joint inflammation, and chronic obstructive pulmonary disease (COPD). Active research on the role of H2S in inflammation will unravel the pathophysiology of its actions in inflammatory conditions and may help develop novel therapeutic approaches for several, as yet incurable, disease conditions.

Bhatia, Madhav

2012-01-01

183

Novel Insights Into Hydrogen Sulfide-Mediated Cytoprotection  

PubMed Central

Abstract Hydrogen sulfide (H2S) is a colorless, water soluble, flammable gas that has the characteristic smell of rotten eggs. Like other members of the gasotransmitter family (nitric oxide and carbon monoxide), H2S has traditionally been considered to be a highly toxic gas and environmental hazard. However, much like for nitric oxide and carbon monoxide, the initial negative perception of H2S has evolved with the discovery that H2S is produced enzymatically in mammals under normal conditions. As a result of this discovery, there has been a great deal of work to elucidate the physiological role of H2S. H2S is now recognized to be cytoprotective in various models of cellular injury. Specifically, it has been demonstrated that the acute administration of H2S, either prior to ischemia or at reperfusion, significantly ameliorates in vitro or in vivo myocardial and hepatic ischemia-reperfusion injury. These studies have also demonstrated a cardioprotective role for endogenous H2S. This review article summarizes the current body of evidence demonstrating the cytoprotective effects of H2S with an emphasis on the cardioprotective effects. This review also provides a detailed description of the current signaling mechanisms shown to be responsible for these cardioprotective actions. Antioxid. Redox Signal. 12, 1203–1217.

Calvert, John W.; Coetzee, William A.

2010-01-01

184

Selective Catalytic Oxidation of Hydrogen Sulfide--IGCC Applications  

SciTech Connect

Selective catalytic oxidation of hydrogen sulfide (SCOHS) to elemental sulfur using activated carbon and NETL-processed metal oxide catalyst systems has been investigated under bench-scale, simulated pressurized IGCC conditions for use in dry and humid gas cleaning process applications. For this technology to be successful, a 20% cost effective advantage and 1 percentage-point plant efficiency gain over current commercial technology, and <10-15 ppm total gas phase sulfur release into the effluent gas stream must be demonstrated. The results of our bench-scale catalyst/sorbent desulfurization and regeneration efforts for both bulk and polishing sulfur removal indicate that direct selective catalytic oxidation of H2S to elemental sulfur utilizing current activated carbon systems occurs only under conditions of low syngas temperature (<150°C), and in syngas effluent streams containing a low water and CO content. Thus the SCOHS desulfurization process is considered to be only potentially feasible for use in dry gas cleaning conditions for IGCC applications where syngas-CO is shifted to CO2, and regeneration of the catalyst occurs through heating in warm CO2, with simultaneous CO2 sequestration. SCOHS is not considered as a candidate desulfurization approach for use in humid IGCC gas cleaning applications.

Alvin, M.A.; Stevens, R.W.; Newby, R.A.; Keairns, D.L.

2006-09-01

185

Novel Composite Hydrogen-Permeable Membranes for Nonthermal Plasma Reactors for the Decomposition of Hydrogen Sulfide  

SciTech Connect

The goal of this experimental project was to design and fabricate a reactor and membrane test cell to dissociate hydrogen sulfide (H{sub 2}S) in a nonthermal plasma and to recover hydrogen (H{sub 2}) through a superpermeable multi-layer membrane. Superpermeability of hydrogen atoms (H) has been reported by some researchers using membranes made of Group V transition metals (niobium, tantalum, vanadium, and their alloys), but it was not achieved at the moderate pressure conditions used in this study. However, H{sub 2}S was successfully decomposed at energy efficiencies higher than any other reports for the high H{sub 2}S concentration and moderate pressures (corresponding to high reactor throughputs) used in this study.

Morris Argyle; John Ackerman; Suresh Muknahallipatna; Jerry Hamann; Stanislaw Legowski; Gui-Bing Zhao; Sanil John; Ji-Jun Zhang; Linna Wang

2007-09-30

186

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

PubMed

A sulfide-resistant ctrain of Thiobacillus denitrificans, strain F, prevented the accumulation of sulfide by Desulfovibrio desulfuricans when both organisms were grown in liquid medium or in Berea sandstone cores. The wild-type strain of T. denitrificans did not prevent the accumulation of sulfide produced by D. desulfuricans. Strain F also prevented the accumulation of sulfide by a mixed population of sulfate-reducing bacteria enriched from an oil field brine. Fermentation balances showed that strain F stoichiometrically oxidized the sulfide produced by D. desulfuricans and the oil field brine enrichment to sulfate. These data suggest that strain F would be effective in controlling sulfide production in oil reservoirs and other environments. PMID:18592547

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

1990-03-01

187

Can Hydrogen Sulfide Gas Be a Biosignature in a Habitable Exoplanet?  

NASA Astrophysics Data System (ADS)

A group of microorganisms can disproportionate sulfite and elemental sulfur into sulfide and sulfate to obtain energy for a living. We explore if the sulfide produced by microorganisms can alter the atmospheric composition to manifest in the spectrum of a habitable exoplanet. We consider a dry (i.e., limited ocean cover) habitable planet of Earth size and mass, orbiting a Sun-like star. As on Earth, volcanoes release sulfur as sulfur dioxide and hydrogen sulfide, but the volcanic production of hydrogen sulfide is limited by the scarcity of water. In the meantime, in our scenario, microbes can flourish in the ocean and effectively make use of the energy gained from the sulfur disproportion and release sulfide as the metabolic byproduct. The metabolic sulfur disproportion can enhance the overall outgassing rate of hydrogen sulfide by nearly one order of magnitude over the non-biological emission. To study the atmospheric response to this enhancement, we build a one-dimensional chemical transport model that treats all O, H and S bearing species and the relevant photochemical and chemical reactions. The vertical transport is approximated with the eddy diffusion. We also consider the formation and the sedimentation of elemental sulfur aerosols and sulfate aerosols in the atmosphere and explore the effect of aerosol particle size on the chemistry and the radiative transfer. To establish hydrogen sulfide as a biosignature, we need to understand the atmospheric response to the sulfide outgassing, the spectral features of hydrogen sulfide and its photochemical products, and the volcanic release of H2S. The current work will address the first two problems, and the main uncertainty will remain at the possible false positives due to the volcanism.

Hu, Renyu; Seager, S.; Bains, W.

2011-05-01

188

Studies of molybdenum sulfide catalysts: effects of pretreatment on olefin hydrogenation activity  

SciTech Connect

Various models have been proposed for the active sites in hydrogenation and hydrogenolysis reactions on molybdenum sulfide catalysts. The role played by edge and basal sites of the sulfide in both oxygen chemisorption and in hydrogenation is still moot, although the question has been often investigated. The authors have chosen to study the effect of catalyst preparation and pretreatment on the properties of unsupported molybdenum disulfide, to avoid some of the problems involved in characterizing supported catalysts. The unsupported sulfide was prepared in situ by the thermal decomposition of ammonium tetrathiomolybdate (ATTM) in flowing helium. In the present paper, unsupported molybdenum sulfide catalysts have been tested for catalytic activity in propene hydrogenation after various pretreatments. This was selected as a test reaction because it gives good conversions at temperatures below the TPR peaks; these mild conditions do not destroy the effects of catalyst pretreatment. Activity was measured with a pulse method, with determination of kinetic constants by a procedure recently described. 44 references.

Kalthod, D.G.; Weller, S.W.

1986-04-01

189

Dynamics of Withdrawal and Backflow of Sulfide Liquids and the Formation of Magmatic Ni-Cu-PGE Sulfide Deposits: Theory and Analogue Modeling  

NASA Astrophysics Data System (ADS)

Sulfide liquids precipitated from silicate magmas after sulfide saturation represent a volumetrically small portion of magmatic systems, but are responsible for the formation of orthomagmatic Ni-Cu-PGE sulfide deposits. Compared to silicate melts, immiscible magmatic sulfide liquids have lower viscosities (by 1 to 3 orders of magnitude), higher densities ( >1500 kg/m3 higher; also significantly higher than surrounding crust) and lower solidus temperatures (>150°C lower). These properties hinder the withdrawal of sulfide liquid from magma staging chambers and its ascent to higher structural levels, and allow for late-stage mobility and downward percolation along grain boundaries and fractures within wall rocks. Prior to emplacement towards higher crustal levels, sulfide liquid will have a tendency to accumulate and pond at the bottom of staging chambers. Later mobilization and upward or lateral withdrawal of sulfide can occur by viscous entrainment within relatively buoyant (mafic) magma. Analytical solutions (e.g., Blake and Ivey, 1986, JVGR, 27, 153-178) applied to the low viscosities, high densities and the likely relatively high volumetric flow rates (Q) in mafic melt-sulfide liquid systems predicts that significant draw-up of sulfide liquid within mafic magmas can occur at high, yet realistic flow rates (10-1000 m3/s), at reasonable Reynolds (>1000) and Weber numbers (0.07-700). At lower Q and Re draw up is hindered by interfacial tension, as indicated by the low capillary numbers of the system. We evaluate the dynamics of withdrawal and entrainment of sulfide liquid using analogue models scaled to mafic-sulfide system, focusing on flow rates and the viscosity and density ratios between sulfide and mafic magmas, in order to further explore the conditions under which sulfide liquids can be effectively entrained to promote the generation of deposits elsewhere in the magma system. The dynamics of sulfide percolation are analogous to the behavior of dense non-aqueous phase liquids (DNAPL). In fractured systems sulfide backflow is strongly controlled by the column height of the dense liquid. Because dense fluids flow downwards, this column generates a higher vertical body force if the network of down-flowing fluid remains interconnected. To enter a fracture, the fluid must overcome a capillary pressure which is inversely proportional to the width of a fracture; thinner fracture widths can be intruded as a body of dense fluid percolates downwards. Such a process, along with late stage mobility of sulfide liquid, could explain the presence of thin (cm to m sized) massive sulfide injections into wall rocks observed at Ni-Cu deposits such as Voisey's Bay (Labrador, CAN), Eagle (Michigan, USA), and Sudbury's late offset dykes.

Saumur, B. M.; Cruden, A. R.

2012-12-01

190

Hydrogen sulfide gas emission under turbulent conditions - an experimental approach for free-fall drops.  

PubMed

Odor nuisance and sulfide corrosion in sewers carrying septic wastewater are accelerated at points of turbulence such as drops in manholes, but accurate methods or empirical expressions to evaluate the gas stripping rate at those particular sites are still missing. With the aim of improving the current knowledge on the influence of free-fall drops on the release of hydrogen sulfide gas, an experimental set-up was built allowing different free-fall drops heights and flows. Three types of experiments were carried out: reaeration tests without sulfide; sulfide oxidation tests; and hydrogen sulfide release tests. With the increase of the free-fall drop height or of the flow, a higher rate of air-to-water mass oxygen transfer was observed. Results regarding sulfide oxidation tests with reaeration through the free-fall have shown that the oxidation rate was correlated with flow. In the hydrogen sulfide release tests, the maximum concentration in the atmosphere reached 500 ppm. Results also showed that increasing the flow rate decreased the time at which the maximum concentrations in the atmosphere were observed. PMID:24473293

Matias, N M; Matos, J S; Ferreira, F

2014-01-01

191

Recovery of calcium carbonate and hydrogen sulfide from waste calcium sulfide  

Microsoft Academic Search

The removal of HâS from hot coal gas using a limestone-based sorbent generates a large quantity of calcium sulfide waste (e.g., 67 tons\\/day from the gasification of 1,000 tons\\/day of 3% S coal) that cannot be landfilled because of potential HâS evolution and sulfide leaching. In the process proposed here, the CaS is dissolved by reaction with HâS complexed with

Mark W. Brooks; Scott Lynn

1997-01-01

192

Relationship of soil hydrogen sulfide level to net carbon assimilation ofPanicum hemitomon andSpartina patens  

Microsoft Academic Search

Panicum hemitomon Schult andSpartina patens (Ait) Muhl. plants from Louisiana Gulf Coast fresh and brackish marshes were subjected to hydrogen sulfide under controlled sediment redox conditions. Net carbon assimilation responses of both species to the combined sediment anaerobiosis and hydrogen sulfide concentrations was measured.Panicum hemitomon was more sensitive to hydrogen sulfide as compared toSpartina patens. Initiation of reduction in net

S. R. Pezeshki; R. D. DeLaune; S. Z. Pan

1991-01-01

193

Solubility of hydrogen sulfide in aqueous solutions of Fe(II) complexes of trans-1,2-cyclohexanediaminetetraacetic acid  

Microsoft Academic Search

Hydrogen sulfide is part of a well-known environmental problem afflicting pulp mills exploiting the Kraft mill sulfate-pulp process. Among the total reduced sulfurs (TRS) quartet (H2S, CH3SH, CH3SCH3, CH3S2CH3), hydrogen sulfide is the most abundant component in the effluents. Utilization of Fe(III) chelate complex of trans-1,2-cyclohexanediaminetetraacetic acid (CDTA) for the oxidation of hydrogen sulfide is beneficial from the standpoint of

Maria C. Iliuta; Bernard P. A. Grandjean

2004-01-01

194

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

Microsoft Academic Search

Two new, simple and accurate methods for the determination of sulfide (S2?) at low levels (?gL?1) in aqueous samples were developed. The generation of hydrogen sulfide (H2S) took place in a coil where sulfide reacted with hydrochloric acid. The resulting H2S was then introduced as a vapor into an inductively coupled plasma-atomic emission spectrometer (ICP-AES) and sulfur emission intensity was

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

2008-01-01

195

The Role of Water for Photodecomposition of Aqueous Hydrogen Sulfide Using Stratified Photocatalyst-Experimental Part  

NASA Astrophysics Data System (ADS)

Splitting of hydrogen sulfide using sunlight is a useful reaction to produce hydrogen. Alkaline sulfide solution, which is prepared by dissolving hydrogen sulfide into alkaline water, is selected as the reaction medium of photocatalytic hydrogen generation reaction. In this system, the photocatalytic reaction is assumed to occur as follows: 2H2O + 2e- --> H2 + 2OH- (1) 2S2- + 2h+ --> S22- (2) However, as the reaction progresses white solids precipitate in the reaction medium. Furthermore, the HPLC analysis suggested that the ratio between the consumption of sulfide ion and the amount of hydrogen generation was about 3:2, which is not stoichiometric. Thus, in this paper, we characterized the white solid precipitate and tried to optimize the solution condition to prevent the precipitation of the same. From our study, the white solid precipitate was confirmed as sulfur derived from the oxidation of the disulfide ion. It was confirmed that the addition of sulfite ions prevented the oxidation of disulfide ions, which causes the precipitation. In the absence of sulfite ions and for sufide ion concentration less than 0.1M, the precipitation of sulfur occurs in a very short reaction time. On the other hand the hydrogen evolution rate retarded when the sulfide ion concentration is higher than 0.1M. This was due to the degradation of the stratified CdS particles. Thus, the optimal concentration of Na2S solution was determined to be around 0.1M.

Arai, Takeo; Matsumoto, Takatoshi; Sakima, Shuhei; Shinoda, Kozo; Nagashima, Umpei; Tohji, Kazuyuki

2006-05-01

196

Role of hydrogen sulfide in secondary neuronal injury.  

PubMed

In acute neuronal insult events, such as stroke, traumatic brain injury, and spinal cord injury, pathological processes of secondary neuronal injury play a key role in the severity of insult and clinical prognosis. Along with nitric oxide (NO) and carbon monoxide (CO), hydrogen sulfide (H2S) is regarded as the third gasotransmitter and endogenous neuromodulator and plays multiple roles in the central nervous system under physiological and pathological states, especially in secondary neuronal injury. The endogenous level of H2S in the brain is significantly higher than that in peripheral tissues, and is mainly formed by cystathionine ?-synthase (CBS) in astrocytes and released in response to neuronal excitation. The mechanism of secondary neuronal injury exacerbating the damage caused by the initial insult includes microcirculation failure, glutamate-mediated excitotoxicity, oxidative stress, inflammatory responses, neuronal apoptosis and calcium overload. H2S dilates cerebral vessels by activating smooth muscle cell plasma membrane ATP-sensitive K channels (KATP channels). This modification occurs on specific cysteine residues of the KATP channel proteins which are S-sulfhydrated. H2S counteracts glutamate-mediated excitotoxicity by inducing astrocytes to intake more glutamate from the extracellular space and thus increasing glutathione in neurons. In addition, H2S protects neurons from secondary neuronal injury by functioning as an anti-oxidant, anti-inflammatory and anti-apoptotic mediator. However, there are still some reports suggest that H2S elevates neuronal Ca(2+) concentration and may contribute to the formation of calcium overload in secondary neuronal injury. H2S also elicits calcium waves in primary cultures of astrocytes and may mediate signals between neurons and glia. Consequently, further exploration of the molecular mechanisms of H2S in secondary neuronal injury will provide important insights into its potential therapeutic uses for the treatment of acute neuronal insult events. PMID:24239876

Wang, Jun-Feng; Li, Yu; Song, Jin-Ning; Pang, Hong-Gang

2014-01-01

197

Intermittent control procedures for the Geysers hydrogen sulfide emission abatement  

SciTech Connect

Pacific Gas and Electric Company (PG and E) operates the world's largest geothermal steam electric power generation facility, currently about 1.140 megawatts (Mw). This facility is located about 80 miles north of San Francisco, California and is within a region referred to as the Known Geothermal Resource Area (KGRA). Pollutants resulting from this method of electric power generation are due to impurities in the geothermal steam. A major contaminate in the steam is hydrogen sulfide (H/sub 2/S), a regulated pollutant in California. The ambient air quality standard (AAQS) for this pollutant in California is 0.03 parts per million (ppM) averaged over one hour. H/sub 2/S is an invisible, unpleasant smelling gas present in varying concentrations in the geothermal steam. Its odor has been compared to the smell of rotten eggs. Since PG and E is increasingly relying on this source of electrical power generation, it has committed millions of dollars to the development, testing, acquisition, and installation of abatement equipment to reduce H/sub 2/S emissions during the past ten years. In order to reduce the number of exceeds of the AAQS during this developmental period, a predictive model was needed for interim abatement purposes. Most of the high hourly H/sub 2/S values occur with meteorological conditions having poor ventilation resulting from a combination of low wind speed and reduced mixing layer depths. This weather condition is most common during the months of June through October in California. A predictive model was developed from three years of hourly H/sub 2/S measurements of 0.03 ppM or greater in populated areas downwind of the generation facility and from observations of associated meteorological data.

Buick, B.D.; Mooney, M.L.

1984-01-01

198

Microplate-based colorimetric detection of free hydrogen sulfide.  

PubMed

Hydrogen sulfide (H2S) has recently been recognized as an important physiologically relevant gasotransmitter. Produced by the enzymes involved in the transsulfuration pathway, cystathionine ?-synthase (CBS) and cystathionine ?-lyase (CSE), H2S has been implicated to control biological activity in virtually every organ system. In recent years it is being recognized that many commonly used H2S assays do not measure free H2S specifically and may be prone to artifacts. This has led to large variations in the reported H2S biological concentrations. In order to accurately study H2S's functions in biological systems accurate assays which measure free H2S specifically are required. In this work we present a simple microplate-based colorimetric assay for H2S gas. The underside of a 96-well microplate cover was coated with Nafion polymer doped with Ag(+) ions. H2S is a highly volatile gas, and as it is volatilized in the microplate well it reacts with Ag(+) to produce Ag2S nanoparticles, which have a strong absorbance in the low-UV range. By monitoring the absorbance change from formation of Ag2S nanoparticles, H2S production can be monitored in real time. The assay has a limit of detection (LOD) of 2.61 nmol (8.70 ?M) and a liner range up to 30 nmol (100 ?M). Using the assay, the KM and Vmax of recombinant CSE enzyme were determined to be 11.13 ± 0.57 mM and 0.45 ± 0.01 nmol min(-1), respectively. H2S production from mouse liver homogenate under aerobic conditions in the presence of cysteine was measured and determined to be 4.89 ± 0.19 nmol min(-1) mL(-1) homogenate. The assay is simple, low cost, and specific to free H2S gas. PMID:23477661

Jarosz, Artur P; Yep, Terence; Mutus, Bulent

2013-04-01

199

Design and synthesis of polymeric hydrogen sulfide donors.  

PubMed

Hydrogen sulfide (H2S) is a gaseous signaling molecule that has several important biological functions in the human body. Because of the difficulties of handling H2S gas, small organic compounds that release H2S under physiological conditions have been developed. The observed bioactivities of these H2S donors have generally been directly correlated with their H2S release properties. However, apart from H2S release, these H2S donors also exert biological effects by direct interaction with intracellular components within the cytoplasm after passive diffusion across cellular membranes. Here we report polymeric H2S donors based on ADT-OH which would alter cellular trafficking of ADT-OH to minimize the unfavorable interactions with intracellular components. We designed and synthesized a poly(ethylene glycol)-ADT (PEG-ADT) conjugate having ADT linked via an ether bond. Whereas ADT-OH significantly reduced cell viability in murine macrophages, the PEG-ADT conjugate did not show obvious cytotoxicity. The PEG-ADT conjugate released H2S in murine macrophages but not in the presence of serum proteins. The PEG-ADT conjugate was taken up by the cell through the endocytic pathway and stayed inside endolysosomes, which is different from the small amphiphilic donor ADT-OH that can directly enter the cytoplasm. Furthermore, PEG-ADT was capable of potentiating LPS-induced inflammation. This polymeric H2S donor approach may help to better understand the H2S bioactivities of the H2S donor ADT-OH. PMID:24942989

Hasegawa, Urara; van der Vlies, André J

2014-07-16

200

Targeting hydrogen sulfide as a promising therapeutic strategy for atherosclerosis.  

PubMed

Physiological concentrations of nitric oxide (NO) and carbon monoxide (CO) have multiple protective effects in the cardiovascular system. Recent studies have implicated hydrogen sulfide (H2S) as a new member of vasculoprotective gasotransmitter family, behaving similarly to NO and CO. H2S has been demonstrated to inhibit multiple key aspects of atherosclerosis, including atherogenic modification of LDL, monocytes adhesion to the endothelial cells, macrophage-derived foam cell formation and inflammation, smooth muscle cell proliferation, neointimal hyperplasia, vascular calcification, and thrombogenesis. H2S also decreases plasma homocysteine levels in experimental animal models. In the human body, H2S production is predominantly catalyzed by cystathionine-?-synthase (CBS) and cystathionine ?-lyase (CSE). CSE is the primary H2S-producing enzyme in the vasculature. Growing evidence suggests that atherosclerosis is associated with vascular CSE/H2S deficiency and that H2S supplementation by exogenous H2S donors (such as NaHS and GYY4137) attenuates, and H2S synthesis suppression by inhibitors (such as D, L-propargylglycine) aggravates the development of atherosclerotic plaques. However, it remains elusive whether CSE deficiency plays a causative role in atherosclerosis. A recent study (Circulation. 2013; 127: 2523-2534) demonstrates that decreased endogenous H2S production by CSE genetic deletion accelerates atherosclerosis in athero-prone ApoE-/- mice, pinpointing that endogenously produced H2S by CSE activation may be of benefit in the prevention and treatment of atherosclerosis. This study will facilitate the development of H2S-based pharmaceuticals with therapeutic applications in atherosclerosis-related cardiovascular diseases. PMID:24491853

Xu, Suowen; Liu, Zhiping; Liu, Peiqing

2014-03-15

201

Direct chlorination process for geothermal power plant off-gas - hydrogen sulfide abatement  

SciTech Connect

The Direct Chlorination Process removes hydrogen sulfide from geothermal off-gases by reacting hydrogen sulfide with chlorine in the gas phase. Hydrogen chloride and elemental sulfur are formed by this reaction. The Direct Chlorination Process has been successfully demonstrated by an on-site operation of a pilot plant at the 3 M We HPG-A geothermal power plant in the Puna District on the island of Hawaii. Over 99.5 percent hydrogen sulfide removal was achieved in a single reaction stage. Chlorine gas did not escape the pilot plant, even when 90 percent excess chlorine gas was used. Because of the higher cost of chemicals and the restricted markets in Hawaii, the economic viability of this process in Hawaii is questionable.

Sims, A.V.

1983-06-01

202

Hydrogenation active sites of unsupported molybdenum sulfide catalysts for hydroprocessing heavy oils  

Microsoft Academic Search

The purpose of the present study was to elucidate the nature of the hydrogenation active sites on unsupported molybdenum sulfide catalysts, aimed at the improvement of the catalysts for the slurry processes. The number of hydrogenation active sites was found to relate to the “inflection” on the basal plane of the catalyst particles. The comparison of the catalytic activity to

Y. Iwata; Y. Araki; K. Honna; Y. Miki; K. Sato; H. Shimada

2001-01-01

203

NOVEL COMPOSITE HYDROGEN-PERMEABLE MEMBRANES FOR NON-THERMAL PLASMA REACTORS FOR THE DECOMPOSITION OF HYDROGEN SULFIDE  

Microsoft Academic Search

The goal of this experimental project is to design and fabricate a reactor and membrane test cell to dissociate hydrogen sulfide (HâS) in a non-thermal plasma and recover hydrogen (Hâ) through a superpermeable multi-layer membrane. Superpermeability of hydrogen atoms (H) has been reported by some researchers using membranes made of Group V transition metals (niobium, tantalum, vanadium, and their alloys),

Morris D. Argyle; John F. Ackerman; Suresh Muknahallipatna; Jerry C. Hamann; Stanislaw Legowski; Ji-Jun Zhang; Guibing Zhao; Robyn J. Alcanzare; Linna Wang; Ovid A. Plumb

2004-01-01

204

Methanol and hydrogen sulfide in comet P/Halley  

NASA Technical Reports Server (NTRS)

The Neutral Mass Spectrometer on the Giotto spacecraft measured the gas and ion composition in the coma of comet P/Halley. A detailed model of the ion chemistry inside the contact surface located at 4660 km is used to interpret the measured ion desnity profiles in the 32 to 35 amu/e mass range. The masses 33 and 35 amu/e are dominated by the protonated methanol and hydrogen sulfide ions CH3OH2(+) and H3S(+). Both profiles are essentially compatible with CH3OH and H2S originating from the nucleus only. The production rates relative to water are Y(CH3OH) = Q(CH3OH)/Q(H2O) = 1.7% and Y(H2S) = 0.41%. Our Y(CH3OH) agrees well with a determination from IR spectra obtained about 6 weeks after the Giotto encounter with P/Halley. In 7 other comets IR and microwave observations give Y(CH3OH) values between about 0.7 and 6%, indicating that the methanol abundance shows a strong variability from comet to comet. In three other comets Y(H2S) values between 0.2 and 0.5% have been reported. In addition to H2S(+), only ions containing minor isotopes of H, C, O and S contribute to mass 34 amu/e (e.g. (34)S(+), (13)CH3OH2(+), CH4DO(+)). These contributions can be calculated from the measured densities of the ions containing the major isotopes and the H2S(+) contribution from the measured H3S(+) density. From mass 34 amu/e we can also derive an upper limit of 1% for the abundance of deuterated methanol. This limit is at most marginally compatible with a direct interstellar origin of the CH3OH in P/Halley as the measured interstellar abundance of deuterated methanol is 1 to 6%.

Eberhardt, P.; Meier, R.; Krankowsky, D.; Hodges, R. R.

1994-01-01

205

Gas-sensitive properties of thin tin dioxide films under the influence of hydrogen sulfide  

NASA Astrophysics Data System (ADS)

In order to develop sensors for selective detection of hydrogen sulfide in the air, the characteristics of thin SnO2 films with various additives (Au, Pt) in the volume and deposited catalysts (Pt / Pd, Au) are studied. The films were obtained by magnetron sputtering. The sensor response to H2S (the ratio of the sensor conductivity G1 in the presence of hydrogen sulfide in the gas to the conductivity G0 in the clean air) is studied as a function of the operating temperature and gas concentration in the range 0.1-70 ppm. It is shown that the sensors with the addition of gold in the volume can be used to detect maximum permissible concentrations (7 ppm) of hydrogen sulfide in the working area after stabilization of the characteristics during long-term tests.

Sevast'yanov, E. Yu.; Maksimova, N. K.; Chernikov, E. V.; Firsov, A. A.

2012-11-01

206

Analysis of hypochlorite process for removal of hydrogen sulfide from geothermal gases  

SciTech Connect

Sodium hypochlorite reacts readily with hydrogen sulfide to convert the sulfide ion into free sulfur in a neutral or acid solution and to the sulfate ion in an alkaline solution. Sodium hypochlorite can be generated on site by processing geothermal brine in electrolytic cells. An investigation to determine if this reaction could be economically used to remove hydrogen sulfide from geothermal noncondensible gases is reported. Two processes, the LO-CAT Process and the Stretford Process, were selected for comparison with the hypochlorite process. Three geothermal reservoirs were considered for evaluation: Niland KGRA, Baca KGRA, and The Geysers KGRA. Because of the wide variation in the amount of hydrogen sulfide present at The Geysers, two different gas analyses were considered for treatment. Plants were designed to process the effluent noncondensible gases from a 10 MW/sub e/ geothermal power plant. The effluent gas from each plant was to contain a maximum hydrogen sulfide concentration of 35 ppb. Capital costs were estimated for each of the processes at each of the four sites selected. Operating costs were also calculated for each of the processes at each of the sites. The results of these studies are shown.

Not Available

1980-04-01

207

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

PubMed

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. PMID:18760446

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

2008-11-15

208

Evaluation of feed COD\\/sulfate ratio as a control criterion for the biological hydrogen sulfide production and lead precipitation  

Microsoft Academic Search

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\\/SO42? ratio. This work

Antonio Velasco; Martha Ram ´ õrez; Tania Volke-Sep ´ ulveda; Armando Gonzalez-S; Sergio Revah

209

X-33 Liquid Hydrogen Tanks  

NASA Technical Reports Server (NTRS)

The liquid hydrogen tank is a multi-lobe graphite/epoxy tank with integrally bonded, woven composite joints. The tanks are broken down into three major subgroups: aft dome/bulkhead, mid barrel section, and the forward dome/bulkhead. The vehicle uses two tanks (a left and right hand tank) as the "aft fuselage" of the vehicle, to react all body bending loads, landing gear loads, canted and vertical fin loads and air loads, as well as being used as the cryogenic fuel cells.

Adams, Andrew J.; Buck, P.; Franklin, W.; Yu, T.

1999-01-01

210

PL05 Hydrogen sulfide in plants: From dissipation of excess sulfur to signalling molecule.  

PubMed

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 to represent a mechanism of 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 emerged for a role of H2S in regulation and signalling. Sulfide stabilises 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, and hydrogen sulfide is emerging as an important signalling molecule, similar to its role in the animal and human world. How far H2S function and homeostasis are similar in these diverse organisms, however, remains to be elucidated. PMID:24948223

Kopriva, Stanislav

2013-09-01

211

Methane and hydrogen sulfide emissions in UASB reactors treating domestic wastewater.  

PubMed

The release of CH(4) and H(2)S in UASB reactors was evaluated with the aim to quantify the emissions from the liquid surfaces (three-phase separator and settler compartment) and also from the reactor's discharge hydraulic structures. The studies were carried out in two pilot- (360 L) and one demo-scale (14 m(3)) UASB reactors treating domestic wastewater. As expected, the release rates were much higher across the gas/liquid interfaces of the three-phase separators (5.4-9.7 kg CH(4) m(-2) d(-1) and 23.0-35.8 g S m(-2) d(-1)) as compared with the quiescent settler surfaces (11.0-17.8 g CH(4) m(-2) d(-1) and 0.21 to 0.37 g S m(-2) d(-1)). The decrease of dissolved methane and dissolved hydrogen sulfide was very large in the discharging hydraulic structures very close to the reactor (>60 and >80%, respectively), largely due to the loss to the atmosphere, indicating that the concentration of these compounds will probably fall to values close to zero in the near downstream structures. The emission factors due to the release of dissolved methane in the discharge structure amounted to around 0.040 g CH(4) g COD(infl)(-1) and 0.060 g CH(4) g COD(rem)(-1), representing around 60% of the methane collected in the three-phase separator. PMID:22437020

Souza, C L; Chernicharo, C A L; Melo, G C B

2012-01-01

212

Importance of Hydrogen Sulfide, Thiosulfate, and Methylmercaptan for Growth of Thiobacilli during Simulation of Concrete Corrosion  

PubMed Central

Biogenic sulfuric acid corrosion of concrete surfaces caused by thiobacilli was reproduced in simulation experiments. At 9 months after inoculation with thiobacilli, concrete blocks were severely corroded. The sulfur compounds hydrogen sulfide, thiosulfate, and methylmercaptan were tested for their corrosive action. With hydrogen sulfide, severe corrosion was noted. The flora was dominated by Thiobacillus thiooxidans. Thiosulfate led to medium corrosion and a dominance of Thiobacillus neapolitanus and Thiobacillus intermedius. Methylmercaptan resulted in negligible corrosion. A flora of heterotrophs and fungi grew on the blocks. This result implies that methylmercaptan cannot be degraded by thiobacilli.

Sand, Wolfgang

1987-01-01

213

Importance of hydrogen sulfide, thiosulfate, and methylmercaptan for growth of thiobacilli during simulation of concrete corrosion  

SciTech Connect

Biogenic sulfuric acid corrosion of concrete surfaces caused by thiobacilli was reproduced in simulation experiments. At 9 months after inoculation with thiobacilli, concrete blocks were severely corroded. The sulfur compounds hydrogen sulfide, thiosulfate, and methylmercaptan were tested for their corrosive action. With hydrogen sulfide, severe corrosion was noted. The flora was dominated by Thiobacillus thiooxidans. Thiosulfate led to medium corrosion and a dominance of Thiobacillus neapolitanus and Thiobacillus intermedius. Methylmercaptan resulted in negligible corrosion. A flora of heterotrophs and fungi grew on the blocks. This result implies that methylmercaptan cannot be degraded by thiobacilli.

Sand, W.

1987-07-01

214

Silicate melt removal and sulfide liquid retention in ultramafic rocks of the Duke Island Complex, Southeastern Alaska  

NASA Astrophysics Data System (ADS)

Magmatic Ni-Cu-PGE sulfide mineralization occurs within olivine clinopyroxenite, hornblende-bearing clinopyroxenite, and magnetite-hornblende-rich rocks in the Ural-Alaskan-Type Duke Island Complex in Southeast Alaska. The addition of large amounts of sulfur from country rocks occurred during fractional crystallization of the parental magma when clinopyroxene was becoming a liquidus mineral. Textural interfaces between sulfide and silicate minerals are strongly interlobate, and differ significantly from net-textures that are developed in many Ni-Cu-PGE deposits. Sulfide-free olivine clinopyroxenite is an adcumulate; residual liquid was efficiently expelled from the accumulating crystal pile. A significant interstitial liquid component is observable only in the form of interstitial sulfide in the S-rich rocks. Rounded sulfide inclusions and blebby to vermicular sulfide-silicate intergrowths indicate that silicate crystallization occurred under conditions of sulfide saturation. The presence of dense sulfide liquid inhibited the growth of silicate minerals and led to the development of interlobate grain boundaries. Strong, localized wetting of sulfide liquids on crystallizing silicates, and downward percolation of sulfide liquid through a crystallizing mush may have contributed to the evolution of these textures. Residual silicate liquid was removed from the system due to a combination of buoyant advection and compaction, but dense sulfide liquid remained.

Stifter, Eric C.; Ripley, Edward M.; Li, Chusi

2014-05-01

215

Development of scavenger-free three-way automotive emission control catalysts with reduced hydrogen sulfide formation  

Microsoft Academic Search

Fundamental research work was undertaken to elucidate the mechanism of hydrogen sulfide formation on three-way automotive exhaust catalysts during the lean to rich engine operation sequence and to identify the role of the different catalyst components in this phenomenon. Based upon this knowledge, new catalysts were developed with reduced ability to form hydrogen sulfide by minimizing the storage of sulfur

E. S. Lox; B. H. Engler; E. Koberstein

1989-01-01

216

Design and development of a system to measure ambient levels of hydrogen sulfide and lower mercaptans from a mobile platform  

Microsoft Academic Search

Hydrogen sulfide and other reduced sulfur gases are released into the atmosphere during oil recovery operations. Little is quantitatively known concerning total sulfur flux due to these fugitive emissions. A mobile atmospheric research laboratory (MARL) was constructed to furnish facile, self contained access to oil field operations. An automated instrument that can continuously measure low levels of hydrogen sulfide with

Gary A. Tarver; Purnendu K. Dasgupta

1995-01-01

217

Thermally stable derivatives of propylenepolyamines as protective additives for lubricating oils used in compressors handling hydrogen sulfide-containing gas  

Microsoft Academic Search

In the transmission of natural, associated, and petroleum gases containing hydrogen sulfide, carbon dioxide, water, and other corrosive impurities, problems are created by the saturation of the compressor lubricating oil with these impurities and failure of components of the lubricating and sealing system. Hydrogen sulfide is distinguished by the greatest affinity for oil and the highest corrosivity. Its solubility in

V. A. Trofimov; I. S. Panidi; V. G. Spirkin; L. V. Leonidova; E. A. Kozhekina; M. I. Yakushkin; I. A. Makarovskii

1995-01-01

218

Hydrogen sulfide releasing capacity of natural isothiocyanates: is it a reliable explanation for the multiple biological effects of brassicaceae?  

PubMed

Hydrogen sulfide is an endogenous pleiotropic gasotransmitter, which mediates important physiological effects in the human body. Accordingly, an impaired production of endogenous hydrogen sulfide contributes to the pathogenesis of important disorders. To date, exogenous compounds, acting as hydrogen sulfide-releasing agents, are viewed as promising pharmacotherapeutic agents. In a recent report, the hydrogen sulfide-releasing properties of some synthetic aryl isothiocyanate derivatives have been reported, indicating that the isothiocyanate function can be viewed as a suitable slow hydrogen sulfide-releasing moiety, endowed with the pharmacological potential typical of this gasotransmitter. Many isothiocyanate derivatives (deriving from a myrosinase-mediated transformation of glucosinolates) are well-known secondary metabolites of plants belonging to the family Brassicaceae, a large botanical family comprising many edible species. The phytotherapeutic and nutraceutic usefulness of Brassicaceae in the prevention of important human diseases, such as cancer, neurodegenerative processes and cardiovascular diseases has been widely discussed in the scientific literature. Although these effects have been largely attributed to isothiocyanates, the exact mechanism of action is still unknown. In this experimental work, we aimed to investigate the possible hydrogen sulfide-releasing capacity of some important natural isothiocyanates, studying it in vitro by amperometric detection. Some of the tested natural isothiocyanates exhibited significant hydrogen sulfide release, leading us to hypothesize that hydrogen sulfide may be, at least in part, a relevant player accounting for several biological effects of Brassicaceae. PMID:24963613

Citi, Valentina; Martelli, Alma; Testai, Lara; Marino, Alice; Breschi, Maria C; Calderone, Vincenzo

2014-06-01

219

Characterization of a Novel, Water-Soluble Hydrogen Sulfide-Releasing Molecule (GYY4137) New Insights Into the Biology of Hydrogen Sulfide  

Microsoft Academic Search

Background—The potential biological significance of hydrogen sulfide (H2S) has attracted growing interest in recent years. The aim of this study was to characterize a novel, water-soluble, slow-releasing H2S compound (morpholin-4-ium 4 methoxyphenyl(morpholino) phosphinodithioate (GYY4137)) and evaluate its use as a tool to investigate the cardiovascular biology of this gas. Methods and Results—The acute vasorelaxant effect of drugs was assessed in

Ling Li; Matthew Whiteman; Yan Yi Guan; Kay Li Neo; Yvonne Cheng; Shiau Wei Lee; Yujun Zhao; Rajamanian Baskar; Choon-Hong Tan; Philip K. Moore

220

Design of an atomic layer deposition reactor for hydrogen sulfide compatibility  

NASA Astrophysics Data System (ADS)

A customized atomic layer deposition (ALD) reactor was designed with components compatible with hydrogen sulfide (H2S) chemistry. H2S is used as a reactant for the ALD of metal sulfides. The use of H2S in an ALD reactor requires special attention to safety issues due to its highly toxic, flammable, and corrosive nature. The reactor was designed with respect to materials compatibility of all wetted components with H2S. A customized safety interlock system was developed to shut down the system in the event of toxic gas leakage, power outage, loss of building ventilation or compressed air pressure. ALD of lead sulfide (PbS) and zinc sulfide (ZnS) were demonstrated with no chemical contamination or detectable release of H2S.

Dasgupta, Neil P.; Mack, James F.; Langston, Michael C.; Bousetta, Al; Prinz, Fritz B.

2010-04-01

221

Differential mechanisms underlying neuroprotection of hydrogen sulfide donors against oxidative stress  

PubMed Central

This study investigated whether slow-releasing organic hydrogen sulfide donors act through the same mechanisms as those of inorganic donors to protect neurons from oxidative stress. By inducing oxidative stress in a neuronal cell line HT22 with glutamate, we investigated the protective mechanisms of the organic donors: ADT-OH [5-(4-hydroxyphenyl)-3H-1, 2-dithiole-3-thione], the most widely used moiety for synthesizing slow-releasing hydrogen sulfide donors, and ADT, a methyl derivative of ADT-OH. The organic donors were more potent than the inorganic donor sodium hydrogensulfide (NaHS) in protecting HT22 cells against glutamate toxicity. Consistent with previous publications, NaHS partially restored glutamate-depleted glutathione (GSH) levels, protected HT22 from direct free radical damage induced by hydrogen peroxide (H2O2), and NaHS protection was abolished by a KATP channel blocker glibenclamide. However, neither ADT nor ADT-OH enhanced glutamate-depleted GSH levels or protected HT22 from H2O2-induced oxidative stress. Glibenclamide, which abolished NaHS neuroprotection against oxidative stress, did not block ADT and ADT-OH neuroprotection against glutamate-induced oxidative stress. Unexpectedly, we found that glutamate induced AMPK activation and that compound C, a well-established AMPK inhibitor, remarkably protected HT22 from glutamate-induced oxidative stress, suggesting that AMPK activation contributed to oxidative glutamate toxicity. Interestingly, all hydrogen sulfide donors, including NaHS, remarkably attenuated glutamate-induced AMPK activation. However, under oxidative glutamate toxicity, compound C only increased the viability of HT22 cells treated with NaHS, but did not further increase ADT and ADT-OH neuroprotection. Thus, suppressing AMPK activation likely contributed to ADT and ADT-OH neuroprotection. In conclusion, hydrogen sulfide donors acted through differential mechanisms to confer neuroprotection against oxidative toxicity and suppressing AMPK activation was a possible mechanism underlying neuroprotection of organic hydrogen sulfide donors against oxidative toxicity.

Jia, Jia; Xiao, Yunqi; Wang, Wei; Qing, Lina; Xu, Yinxiu; Song, Heng; Zhen, Xuechu; Ao, Guizhen; Alkayed, Nabil J; Cheng, Jian

2014-01-01

222

Investigation of Causes of Hydrogen Sulfide Formation in Reclaimed Water.  

National Technical Information Service (NTIS)

The factors responsible for the formation of hydrogen sulphide in the water reclaimed from the atmospheric condensate were investigated. It was found that hydrogen sulphide developed in reclaimed water due to microorganisms which in the presence of inorga...

I. G. Popov V. V. Vlodavets S. V. Chizhov Y. Y. Sinyak M. I. Shikina

1986-01-01

223

Solubility of hydrogen sulfide in aqueous mixtures of monoethanolamine with N-methyldiethanolamine  

SciTech Connect

Alkanolamine aqueous solutions are frequently used for the removal of acidic gases, such as CO[sub 2] and H[sub 2]S, from gas streams in the natural gas and synthetic ammonia industries and petroleum chemical plants. The solubilities of hydrogen sulfide in aqueous mixtures of monoethanolamine (MEA) with N-methyl-diethanolamine (MDEA) have been measured at 40, 60, 80, and 100C and at partial pressures of hydrogen sulfide ranging from 1.0 to 450 kPa. The mixtures of alkanolamines studied are 4.95 kmol/m[sup 3] MEA, 3.97 kmol/m[sup 3] MEA + 0.51 kmol/m[sup 3] MDEA, 2.0 kmol/m[sup 3] MEA + 1.54 kmol/m[sup 3] MDEA, and 2.57 kmol/m[sup 3] MDEA aqueous solutions. The solubilities of hydrogen sulfide in aqueous alkanolamine solutions are reported as functions of the partial pressure of hydrogen sulfide at the temperatures of 40-100C.

Meng Hui Li; Keh Perng Shen (Chung Yuan Christian Univ., Chung Li (Taiwan, Province of China). Dept. of Chemical Engineering)

1993-01-01

224

Hot Gas Removal of Tars, Ammonia, and Hydrogen Sulfide from Biomass Gasification Gas  

Microsoft Academic Search

Gasification of biomass is a promising source of fuels and other chemical products. However, the removal of tars, ammonia, hydrogen sulfide, and other byproducts from the raw gas is required. The gas clean?up technology that offers more advantages is hot catalytic gas conditioning downstream of the gasifier reactor. Here, we review the applications of basic, acidic, metallic, and redox catalysts

Walter Torres; Sourabh S. Pansare; James G. Goodwin Jr

2007-01-01

225

Vanadium-based mixed-oxide catalysts for selective oxidation of hydrogen sulfide to sulfur  

SciTech Connect

The petroleum refining industry uses a hydrodesulfurization process to convert the sulfur content of petroleum fractions into hydrogen sulfide. Additionally, natural gas and coal gas also contain 0.3--3 vol% hydrogen sulfide. The selective oxidation of hydrogen sulfide to sulfur was studied over three vanadium-based mixed-oxide catalysts, including the binary oxides of vanadium-molybdenum, vanadium-bismuth, and vanadium-magnesium. The catalytic reaction was carried out in a fixed-bed reactor in the temperature range 200--300 C. Strong synergistic phenomena in catalytic activity and selectivity were observed for the binary oxides. Under identical reaction conditions, the performances of the binary oxide catalysts within certain composition ranges were superior to those of the corresponding single-oxide catalysts. These synergistic phenomena suggest that the new compounds Mo{sub 6}V{sub 9}O{sub 40}, BiVO{sub 4}/Bi{sub 4}V{sub 6}O{sub 21}, and MgV{sub 2}O formed in the binary oxides are much better than the corresponding single-oxide catalysts for the selective oxidation of hydrogen sulfide. The maximum sulfur yield obtained with the vanadium-based binary mixed-oxide catalysts was 97%, which was much higher than that obtained with pure vanadium oxide (78%).

Li, K.T.; Huang, M.Y.; Cheng, W.D. [Tunghai Univ., Taichung (Taiwan, Province of China). Dept. of Chemical Engineering] [Tunghai Univ., Taichung (Taiwan, Province of China). Dept. of Chemical Engineering

1996-02-01

226

Reaction of hydrogen sulfide with oxygen in the presence of sulfite  

SciTech Connect

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.

Weres, O.; Tsao, L.

1983-01-14

227

Determination of a range of concern for mobile source emissions of hydrogen sulfide. Technical report  

Microsoft Academic Search

This report describes an effort by the Emission Control Technology Division of the Environmental Protection Agency to establish a range of concern for hydrogen sulfide (H2S) emissions from mobile sources. Mathematical models that were previously designed for various exposure scenarios (such as enclosed spaces, expressways, and street canyons) were used to calculate the ambient air concentrations resulting from various mobile

1982-01-01

228

Carbon Dioxide and Hydrogen Sulfide Emission Factors Applicable to Wastewater Wet Wells  

Microsoft Academic Search

Transport of wastewater in sewer networks causes potential problems associated with gases which include ammonia, carbon dioxide, carbon monoxide, hydrogen sulfide and methane, in regard to odor nuisance, irritation, toxicity, and microbially induced corrosion. The extent of these problems depends on the emission rates of gases in the sewer atmosphere. To limit these kinds of problems an estimate of the

Madhuri Mudragaddam

2010-01-01

229

Existence of a hydrogen sulfide: Ferric ion oxidoreductase in iron-oxidizing bacteria  

Microsoft Academic Search

The existence of a hydrogen sulfide:ferric ion oxidoreductase, which catalyzes the oxidation of elemental sulfur with ferric ions as an electron acceptor to produce ferrous and sulfite ions, was assayed with washed intact cells and cell extracts of various kinds of iron-oxidizing bacteria, such as Thiobacillus ferrooxidans 13598, 13661, 14119, 19859, 21834, 23270, and 33020 from the American Type Culture

Tsuyoshi Sugio; K. J. White; E. Shute; D. Choate; R. C. Blake

1992-01-01

230

SUMMERTIME CONCENTRATIONS AND EMISSIONS OF HYDROGEN SULFIDE AT A MECHANICALLY VENTILATED SWINE FINISHING BUILDING  

Microsoft Academic Search

Hydrogen sulfide (H2S) concentration and emission at a modern mechanically ventilated swine finishing building with a deep pit were continuously measured for three summer months. Ventilation rates, temperatures, and pig inventory in the building were also continuously measured or recorded. A total of 88 d of valid data were obtained between 26 June and 25 September, during which the average

J.-Q. Ni; A. J. Heber; C. A. Diehl; T. T. Lim; R. K. Duggirala; B. L. Haymore

231

Selective extraction reaction of hydrogen sulfide from coke-oven gas  

Microsoft Academic Search

The results of the calculations show the clear advantages of selective extraction of hydrogen sulfide from the coke-oven gas, which may be accomplished with a short phase contact time in hollow compartmentalized, cyclone, and other types of high-efficiency devices. It is also promising to use a combination of a short contact time of the reacting phase with high extraction temperatures,

Kovalenko

1978-01-01

232

Aqueous studies of hydrogen sulfide releases from a heavy water extraction facility  

Microsoft Academic Search

Upsets in the operation of the wastewater strippers in the 400 Area of the Savannah River Plant have released hydrogen sulfide in quantities as large as 1800 kg to the effluent stream. Fish kills in the swamp area of Beaver Dam Creek have occurred following the large releases. A literature survey revealed volatilization and oxidation as the major loss mechanisms

Kiser

1979-01-01

233

Hydrogenation of 2,5-dimethyl-4-phenyl(p-alkylbenzyl) pyridines over metal sulfides  

Microsoft Academic Search

The corresponding substituted piperidines were obtained in yields from 40 to 99.5% by the hydrogenation of 2,5-dimethyl-4-phenylpyridine and 2,5-dimethyl-4-[p-methyl(p-ethyl)benzyl]pyridines in the presence of rhenium, platinum, and palladium sulfides.

M. A. Ryashentseva; Kh. M. Minachev; Vo V. Dorogov; N. S. Prostakov

1972-01-01

234

Increasing the efficacy of the absorption of hydrogen sulfide in the analysis of natural gases  

SciTech Connect

It is proposed to use 5% CdC1/sub 2/ saturated with sodium sulfate for the absorption of hydrogen sulfide. This solution permits a considerable increase in the sharpness of the separation of H/sub 2/S and mercaptans in the analysis of complex gaseous mixtures.

Kushnir, S.V.; Vivchar, O.I.

1983-01-01

235

Presumed Hydrogen Sulfide-Mediated Neurotoxicity Following Streptococcus Anginosus Group Meningitis  

PubMed Central

Hydrogen sulfide (H2S) is an environmental toxicant and gaseous neurotransmitter. It is produced enterically by sulfur-reducing bacteria and invasive pathogens including Streptococcus anginosus group, Salmonella and Citrobacter. We describe putative focal H2S neurotoxicity following S. constellatus meningitis, treated with adjunctive sodium nitrite and hyperbaric oxygen therapy.

Verma, Sumit; Landisch, Rachel; Quirk, Brendan; Schmainda, Kathleen; Prah, Melissa; Whelan, Harry T.; Willoughby, Rodney E.

2012-01-01

236

Reaction of Hydrogen Sulfide with Oxygen in the Presence ofSulfite  

SciTech Connect

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.

Weres, Oleh; Tsao, Leon

1983-01-01

237

Assessment of Hydrogen Sulfide Minimum Detection Limits of an Open Path Tunable Diode Laser  

EPA Science Inventory

During June 2007, U.S. EPA conducted a feasibility study to determine whether the EPA OTM 10 measurement approach, also known as radial plume mapping (RPM), was feasible. A Boreal open-path tunable diode laser (OP-TDL) to collect path-integrated hydrogen sulfide measurements alon...

238

On the Inhibition of Hydrogen Sulfide Corrosion of Steel with Schiff Bases  

Microsoft Academic Search

The synthesized Schiff bases effectively protect steel in hydrogen sulfide media. Different primary amines were used as the starting reagents to find out how the protection effect of azomethines depends on their nature. It was shown that the higher the electron-donating properties (in terms of normal Wepster constants sH) of substituents in benzaldehyde the better the inhibition of steel corrosion.

Yu. I. Kuznetsov; R. K. Vagapov

2001-01-01

239

Adsorption-chemical method of determining hydrogen sulfide and sulfur dioxide in gas mixtures  

Microsoft Academic Search

mixtures with other gases [5-8] are associated with the use of various aqueous solutions (specifically sodium arsenate in water), which results in a low accuracy in the analyses because of the good solubility of the sample gases in water. The presence of CO z interferes with the determination of sulfur dioxide and hydrogen sulfide. In addition, much time and a

M. A. Ryashentseva; Yu. A. Afanas'eva

1967-01-01

240

Hydrogen sulfide oxidation and the arterial chemoreflex: effect of methemoglobin.  

PubMed

Endogenous H(2)S has been proposed to transduce the effects of hypoxia in the carotid bodies (CB). To test this hypothesis, we created a sink for endogenously produced H(2)S by inducing ?10% methemoglobinemia via the injection of 250 mg of sodium nitrite in spontaneously breathing anaesthetized sheep. Methemoglobinemia has been shown to catalyze the oxidation of large quantities of sulfide in the blood and tissues. We found that the presence of metHb completely abolished the ventilatory stimulation induced by 10 mg NaHS (i.v.), which in control conditions mimicked the effects of breathing 6-7 tidal volumes of nitrogen, confirming the dramatic increase in the oxidative power of the blood for sulfide. The ventilatory responses to hypoxia (10% O(2)), nitrogen and hyperoxia were in no way depressed by the metHb. Our results demonstrate that the ventilatory chemoreflex is not depressed in the presence of a high oxidative capacity for sulfide and challenge the view that H(2)S transduces the effects of hypoxia in the CB. PMID:21569867

Haouzi, Philippe; Bell, Harold; Philmon, Maeve

2011-08-15

241

The anodic behavior of iron in hydrogen sulfide solutions  

SciTech Connect

The anodic behavior of iron in 0.032 mol . L/sup -1/ NaCl/0.003 mol . L/sup -1/ NaHCO/sub 3/ and 1 mol . L/sup -1/ Na/sub 2/SO/sub 4//0.003 mol . L/sup -1/ NaHCO/sub 3/ solutions containing 0.05 mol . L/sup -1/ H/sub 2/S at ambient temperature was studied using cyclic voltammetry and the potentiostatic technique. In both solutions, a nonprotective film of mackinawite (Fe/sub 1+chi/S) was formed on the iron, but the film growth kinetics differ for the two solutions. The film growth in chloride solutions does not appear to follow a conventional type of model for multilayer fils whereas the formation of the film in sulfate solutions can be represented in terms of a pre-resistance model. At more anodic potentials, the mackinawite is oxidized to a higher sulfide, possibly pyrite (FeS/sub 2/), as suggested from a comparison of the anodic and cathodic peak potentials with the equilibrium potential. The formation of the higher sulfide(s) in the chloride solution appears to follow a similar film growth mechanism to that for mackinawite, whereas it is not clear whether this is the case for the sulfate solution.

Pound, B.G. (SRI International, Menlo Park, CA (USA)); Wright, G.A.; Sharp, R.M. (Auckland Univ. (New Zealand). Dept. of Chemistry)

1989-05-01

242

Photocatalytic hydrogen production by direct sun light from sulfide\\/sulfite solution  

Microsoft Academic Search

The photocatalytic hydrogen production from a sulfide\\/sulfite solution is one of the photocatalytic processes that have been of interest recently for hydrogen production. Different types of semiconductor photocatalysts have been prepared and tested for this purpose. In this paper, photocatalysts CdS\\/ZnS that were prepared by a different coprecipitation technique was studied with and without n-Si in sulphide\\/sulphite solution irradiated with

Atif Koca; Musa ?ahin

2002-01-01

243

Corrosion-mechanical resistance of pipe steel in hydrogen-sulfide containing media  

Microsoft Academic Search

We investigate the resistance to hydrogen-sulfide stress corrosion cracking and hydrogen-induced cracking of ASTM A333 steel\\u000a intended for the oil and gas industry. On the basis of the results obtained for seven meltings of this steel supplied for\\u000a the Tengiz gas-processing plant, we established that all meltings satisfy specifications of the NACE MR0175-96 standard in\\u000a their chemical composition and strength

O. I. Radkevych; O. S. P’yasets’kyi; I. I. Vasylenko

2000-01-01

244

Recovery of calcium carbonate and hydrogen sulfide from waste calcium sulfide  

SciTech Connect

The removal of H{sub 2}S from hot coal gas using a limestone-based sorbent generates a large quantity of calcium sulfide waste (e.g., 67 tons/day from the gasification of 1,000 tons/day of 3% S coal) that cannot be landfilled because of potential H{sub 2}S evolution and sulfide leaching. In the process proposed here, the CaS is dissolved by reaction with H{sub 2}S complexed with aqueous MDEA or other alkanolamines. In the second step, the highly soluble Ca(HS){sub 2} reacts readily with CO{sub 2}, also complexed with aqueous MDEA, to precipitate pure CaCO{sub 3} of uniform crystal size and to form MDEA-complexed H{sub 2}S in solution. The solution from step 2 is split--half is recycled to step 1 and half is sent to a stripper to recover H{sub 2}S and from there to the column where the needed CO{sub 2} is absorbed from a combustion gas.

Brooks, M.W.; Lynn, S. [Univ. of California, Berkeley, CA (United States). Dept. of Chemical Engineering] [Univ. of California, Berkeley, CA (United States). Dept. of Chemical Engineering; [Lawrence Berkeley National Lab., CA (United States)

1997-10-01

245

Precipitation of heavy metals from coal ash leachate using biogenic hydrogen sulfide generated from FGD gypsum.  

PubMed

Investigations were undertaken to utilize flue gas desulfurization (FGD) gypsum for the treatment of leachate from the coal ash (CA) dump sites. Bench-scale investigations consisted of three main steps namely hydrogen sulfide (H(2)S) production by sulfate reducing bacteria (SRB) using sulfate from solubilized FGD gypsum as the electron acceptor, followed by leaching of heavy metals (HMs) from coal bottom ash (CBA) and subsequent precipitation of HMs using biologically produced sulfide. Leaching tests of CBA carried out at acidic pH revealed the existence of several HMs such as Cd, Cr, Hg, Pb, Mn, Cu, Ni and Zn. Molasses was used as the electron donor for the biological sulfate reduction (BSR) process which produced sulfide rich effluent with concentration up to 150 mg/L. Sulfide rich effluent from the sulfate reduction process was used to precipitate HMs as metal sulfides from CBA leachate. HM removal in the range from 40 to 100% was obtained through sulfide precipitation. PMID:23168629

Jayaranjan, Madawala Liyanage Duminda; Annachhatre, Ajit P

2013-01-01

246

Use of AERMOD to Determine a Hydrogen Sulfide Emission Factor for Swine Operations by Inverse Modeling.  

PubMed

This study was conducted to determine both optimal settings applied to the plume dispersion model, AERMOD, and a scalable emission factor for accurately determining the spatial distribution of hydrogen sulfide concentrations in the vicinity of swine concentrated animal feeding operations (CAFOs). These operations emit hydrogen sulfide from both housing structures and waste lagoons. With ambient measurements made at 4 stations within 1 km of large swine CAFOs in Iowa, an inverse-modeling approach applied to AERMOD was used to determine hydrogen sulfide emission rates. CAFO buildings were treated as volume sources whereas nearby lagoons were modeled as area sources. The robust highest concentration (RHC), calculated for both measured and modeled concentrations, was used as the metric for adjusting the emission rate until the ratio of the two RHC levels was unity. Utilizing this approach, an average emission flux rate of 0.57 µg/m(2)-s was determined for swine CAFO lagoons. Using the average total animal weight (kg) of each CAFO, an average emission factor of 6.06 × 10(-7) µg/yr-m(2)-kg was calculated. From studies that measured either building or lagoon emission flux rates, building fluxes, on a floor area basis, were considered equal to lagoon flux rates. The emission factor was applied to all CAFOs surrounding the original 4 sites and surrounding an additional 6 sites in Iowa, producing an average modeled-to-measured RHC ratio of 1.24. When the emission factor was applied to AERMOD to simulate the spatial distribution of hydrogen sulfide around a hypothetical large swine CAFO (1M kg), concentrations 0.5 km from the CAFO were 35 ppb and dropped to 2 ppb within 6 km of the CAFO. These values compare to a level of 30 ppb that has been determined by the State of Iowa as a threshold level for ambient hydrogen sulfide levels. PMID:21804761

O'Shaughnessy, Patrick T; Altmaier, Ralph

2011-08-01

247

Use of AERMOD to determine a hydrogen sulfide emission factor for swine operations by inverse modeling  

NASA Astrophysics Data System (ADS)

This study was conducted to determine both optimal settings applied to the plume dispersion model, AERMOD, and a scalable emission factor for accurately determining the spatial distribution of hydrogen sulfide concentrations in the vicinity of swine concentrated animal feeding operations (CAFOs). These operations emit hydrogen sulfide from both housing structures and waste lagoons. With ambient measurements made at 4 stations within 1 km of large swine CAFOs in Iowa, an inverse-modeling approach applied to AERMOD was used to determine hydrogen sulfide emission rates. CAFO buildings were treated as volume sources whereas nearby lagoons were modeled as area sources. The robust highest concentration (RHC), calculated for both measured and modeled concentrations, was used as the metric for adjusting the emission rate until the ratio of the two RHC levels was unity. Utilizing this approach, an average emission flux rate of 0.57 ?g m -2 s -1 was determined for swine CAFO lagoons. Using the average total animal weight (kg) of each CAFO, an average emission factor of 6.06 × 10 -7 ?g yr -1 m -2 kg -1 was calculated. From studies that measured either building or lagoon emission flux rates, building fluxes, on a floor area basis, were considered equal to lagoon flux rates. The emission factor was applied to all CAFOs surrounding the original 4 sites and surrounding an additional 6 sites in Iowa, producing an average modeled-to-measured RHC ratio of 1.24. When the emission factor was applied to AERMOD to simulate the spatial distribution of hydrogen sulfide around a hypothetical large swine CAFO (1 M kg), concentrations within 0.5 km from the CAFO exceeded 25 ppb and dropped to 2 ppb within 6 km of the CAFO. These values compare to a level of 30 ppb that has been determined by the State of Iowa as a threshold level for ambient hydrogen sulfide levels.

O'Shaughnessy, Patrick T.; Altmaier, Ralph

2011-09-01

248

Use of AERMOD to Determine a Hydrogen Sulfide Emission Factor for Swine Operations by Inverse Modeling  

PubMed Central

This study was conducted to determine both optimal settings applied to the plume dispersion model, AERMOD, and a scalable emission factor for accurately determining the spatial distribution of hydrogen sulfide concentrations in the vicinity of swine concentrated animal feeding operations (CAFOs). These operations emit hydrogen sulfide from both housing structures and waste lagoons. With ambient measurements made at 4 stations within 1 km of large swine CAFOs in Iowa, an inverse-modeling approach applied to AERMOD was used to determine hydrogen sulfide emission rates. CAFO buildings were treated as volume sources whereas nearby lagoons were modeled as area sources. The robust highest concentration (RHC), calculated for both measured and modeled concentrations, was used as the metric for adjusting the emission rate until the ratio of the two RHC levels was unity. Utilizing this approach, an average emission flux rate of 0.57 µg/m2-s was determined for swine CAFO lagoons. Using the average total animal weight (kg) of each CAFO, an average emission factor of 6.06 × 10?7 µg/yr-m2-kg was calculated. From studies that measured either building or lagoon emission flux rates, building fluxes, on a floor area basis, were considered equal to lagoon flux rates. The emission factor was applied to all CAFOs surrounding the original 4 sites and surrounding an additional 6 sites in Iowa, producing an average modeled-to-measured RHC ratio of 1.24. When the emission factor was applied to AERMOD to simulate the spatial distribution of hydrogen sulfide around a hypothetical large swine CAFO (1M kg), concentrations 0.5 km from the CAFO were 35 ppb and dropped to 2 ppb within 6 km of the CAFO. These values compare to a level of 30 ppb that has been determined by the State of Iowa as a threshold level for ambient hydrogen sulfide levels.

O'Shaughnessy, Patrick T.; Altmaier, Ralph

2011-01-01

249

Autotrophic denitrification for combined hydrogen sulfide removal from biogas and post-denitrification.  

PubMed

In this paper we describe an alternative flow-chart for full treatment of wastewaters rich in organic substrates, ammonia (or organic nitrogen), and sulfate, such as those generated in fish cannery industries. Biogas generated during anaerobic pretreatment of these wastewaters is rich in hydrogen sulfide that needs to be removed to enable application of the biogas. Nitrogen elimination is traditionally achieved by subsequent nitrification and denitrification of the effluent of the anaerobic reactor. Alternatively, the hydrogen sulfide in the biogas can be applied as an electron donor in an autotrophic post-denitrification step. In order to study whether sufficient hydrogen sulfide containing biogas for denitrification was produced in the anaerobic reactor, the biogas composition as a function of the anaerobic reactor-pH was estimated based on a typical wastewater composition and chemical equilibrium equations. It is demonstrated that typical sulfate and nitrogen concentrations in fish cannery wastewater are highly appropriate for application of autotrophic post-denitrification. A literature review furthermore suggested that the kinetic parameters for autotrophic denitrification by Thiobacillus denitrificans represent no bottleneck for its application. Initial experimental studies in fixed-film reactors were conducted with sodium sulfide and nitrate as an electron donor-acceptor couple. The results revealed that only moderate volumetric treatment capacities (< 1 g-NO3- N l(-1) day(-1)) could be achieved. Mass balances suggested that incomplete sulfide oxidation to elemental sulfur occurred, limiting biomass retention and the treatment capacity of the reactor. Future research should clarify the questions concerning product formation from sulfide oxidation. PMID:12188569

Kleerebezem, R; Mendez, R

2002-01-01

250

Hydrogen sulfide adsorption on MOFs and MOF/graphite oxide composites.  

PubMed

Composites of a copper-based metal-organic framework (MOF) and graphite oxide (GO) were tested for hydrogen sulfide removal at ambient conditions. In order to understand the mechanisms of adsorption, the initial and exhausted samples were analyzed by various techniques including X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analyses, and sorption of nitrogen. Compared to the parent materials, an enhancement in hydrogen sulfide adsorption was found. It was the result of physical adsorption of water and H(2)S in the pore space formed at the interface between the MOF units and the graphene layers where the dispersive forces are the strongest. Besides physisorption, reactive adsorption was found as the main mechanism of retention. H(2)S molecules bind to the copper centers of the MOF. They progressively react with the MOF units resulting in the formation of copper sulfide. This leads to the collapse of the MOF structure. Water enhances adsorption in the composites as it allows the dissolution of hydrogen sulfide. PMID:20945452

Petit, Camille; Mendoza, Barbara; Bandosz, Teresa J

2010-12-01

251

Electrochemical polishing of hydrogen sulfide from coal synthesis gas  

SciTech Connect

An advanced process has been developed for the separation of H{sub 2}S from coal gasification product streams through an electrochemical membrane. This technology is developed for use in coal gasification facilities providing fuel for cogeneration coal fired electrical power facilities and Molten Carbonate Fuel Cell electrical power facilities. H{sub 2}S is removed from the syn-gas by reduction to the sulfide ion and H at the cathode. The sulfide ion migrates to the anode through a molten salt electrolyte suspended in an inert ceramic matrix. Once at the anode it is oxidized to elemental sulfur and swept away for condensation in an inert gas stream. The syn-gas is enriched with the H{sub 2}. Order-of-magnitude reductions in H{sub 2}S have been repeatably recorded (100 ppm to 10 ppm H{sub 2}S) on a single pass through the cell. This process allows removal of H{sub 2}S without cooling the gas stream and with negligible pressure loss through the separator. Since there are no absorbents used, there is no absorption/regeneration step as with conventional technology. Elemental sulfur is produced as a by-product directly, so there is no need for a Claus process for sulfur recovery. This makes the process economically attractive since it is much less equipment intensive than conventional technology.

Gleason, E.F.; Winnick, J.

1995-11-01

252

Control of hydrogen sulfide production in oil fields by managing microbial communities through nitrate or nitrite addition  

Microsoft Academic Search

Nitrate or nitrite injection into oil reservoirs during water flooding has the potential to control biological souring, the production of hydrogen sulfide (H2S) by sulfate-reducing bacteria (SRB). Souring control is essential because sulfide is toxic, sulfide precipitates can plug reservoir formations, souring lowers crude oil value, and SRB induce corrosion. Nitrate and nitrite can stimulate heterotrophic nitrate- or nitrite-reducing bacteria

Casey R. J. Hubert

2004-01-01

253

Development of Automotive Liquid Hydrogen Storage Systems  

Microsoft Academic Search

Liquid hydrogen (LH2) takes up less storage volume than gas but requires cryogenic vessels. State-of-the-art applications for passenger vehicles consist of double-wall cylindrical tanks that hold a hydrogen storage mass of up to 10 kg. The preferred shell material of the tanks is stainless steel, since it is very resistant against hydrogen brittleness and shows negligible hydrogen permeation. Therefore, the

G. Krainz; G. Bartlok; P. Bodner; P. Casapicola; Ch. Doeller; F. Hofmeister; E. Neubacher; A. Zieger

2004-01-01

254

Effect of Hydrogen Sulfide on Fish and Invertebrates. Part II - Hydrogen Sulfide Determination and Relationship Between pH and Sulfide Toxicity.  

National Technical Information Service (NTIS)

An analytical method was developed for the direct determination of microgram/liter concentrations of molecular H2S. The procedure involves bubbling compressed nitrogen through an aqueous sulfide solution to displace H2S which is collected in a glass bead ...

S. J. Broderius L. L. Smith

1976-01-01

255

Method of removing hydrogen sulfide from gases utilizing a zinc oxide sorbent and regenerating the sorbent  

DOEpatents

A spent solid sorbent resulting from the removal of hydrogen sulfide from a fuel gas flow is regenerated with a steam-air mixture. The mixture of steam and air may also include additional nitrogen or carbon dioxide. The gas mixture contacts the spent sorbent containing metal sulfide at a temperature above 500.degree. C. to regenerate the sulfide to metal oxide or carbonate. Various metal species including the period four transition metals and the lanthanides are suitable sorbents that may be regenerated by this method. In addition, the introduction of carbon dioxide gas permits carbonates such as those of strontium, barium and calcium to be regenerated. The steam permits regeneration of spent sorbent without formation of metal sulfate. Moreover, the regeneration will proceed with low oxygen concentrations and will occur without the increase in temperature to minimize the risk of sintering and densification of the sorbent.

Jalan, Vinod M. (Concord, MA); Frost, David G. (Maynard, MA)

1984-01-01

256

Silver sulfide cathode for liquid ammonia batteries and fuel cells containing sulfur and HâS in the electrolyte  

Microsoft Academic Search

An electrochemical cell having an anode and a cathode and using acid acting liquid ammonia electrolytes is described comprising: (a) an insoluble, reducible cathode material consisting of a silver sulfide compound; (b) said acid acting liquid ammonia electrolyte containing sulfur and HâS in solution; (c) said silver sulfide compound being consumed in the cathodic reaction with the silver undergoing the

Miles

1973-01-01

257

Hydrogen Sulfide Protects HUVECs against Hydrogen Peroxide Induced Mitochondrial Dysfunction and Oxidative Stress  

PubMed Central

Background Hydrogen sulfide (H2S) has been shown to have cytoprotective effects in models of hypertension, ischemia/reperfusion and Alzheimer's disease. However, little is known about its effects or mechanisms of action in atherosclerosis. Therefore, in the current study we evaluated the pharmacological effects of H2S on antioxidant defenses and mitochondria protection against hydrogen peroxide (H2O2) induced endothelial cells damage. Methodology and Principal Findings H2S, at non-cytotoxic levels, exerts a concentration dependent protective effect in human umbilical vein endothelial cells (HUVECs) exposed to H2O2. Analysis of ATP synthesis, mitochondrial membrane potential (??m) and cytochrome c release from mitochondria indicated that mitochondrial function was preserved by pretreatment with H2S. In contrast, in H2O2 exposed endothelial cells mitochondria appeared swollen or ruptured. In additional experiments, H2S was also found to preserve the activities and protein expressions levels of the antioxidants enzymes, superoxide dismutase, catalase, glutathione peroxidase and glutathione-S-transferase in H2O2 exposed cells. ROS and lipid peroxidation, as assessed by measuring H2DCFDA, dihydroethidium (DHE), diphenyl-l-pyrenylphosphine (DPPP) and malonaldehyde (MDA) levels, were also inhibited by H2S treatment. Interestingly, in the current model, D, L-propargylglycine (PAG), a selective inhibitor of cystathionine ?-lyase (CSE), abolished the protective effects of H2S donors. Innovation This study is the first to show that H2S can inhibit H2O2 mediated mitochondrial dysfunction in human endothelial cells by preserving antioxidant defences. Significance H2S may protect against atherosclerosis by preventing H2O2 induced injury to endothelial cells. These effects appear to be mediated via the preservation of mitochondrial function and by reducing the deleterious effects of oxidative stress.

Wen, Ya-Dan; Wang, Hong; Kho, Sok-Hong; Rinkiko, Suguro; Sheng, Xiong; Shen, Han-Ming; Zhu, Yi-Zhun

2013-01-01

258

Direct determination of molecular hydrogen sulfide in sewage effluents  

SciTech Connect

In this work, the direct determination of H{sub 2}S in sewage samples was determined using a method which involves bubbling nitrogen through the aqueous sulfide solution to strip all the H{sub 2}S which could escape to the gas phase and measure it by and H{sub 2}S-gas detector. The amount of molecular H{sub 2}S was determined from the calculation of the total area under the curve relating the volume of nitrogen (L) and H{sub 2}S concentration (mg/L) in the gas phase. The area was calculated using the Trapezoidal Numerical Method. The H{sub 2}S for the same sewage sample was also determined by using the standard iodine method.

Abdul-Wahab, S.A. (Ministry of Public Health, Safat (Kuwait)); Al-Haddad, A.A.; Abdo, M.S.E. (Kuwait Univ., Safat (Kuwait))

1990-10-01

259

Atmospheric hydrogen sulfide over the equatorial Pacific (SAGA 3)  

SciTech Connect

Atmospheric H{sub 2}S concentrations were measured over the equatorial Pacific on leg 1 of the third Soviet-American Gases and Aerosols (SAGA 3) cruise during February and March 1990. Five N-S transects were made across the equator between Hawaii and American Samoa. The concentrations ranged from below the detection limit of 0.4 {+-} 0.5 (1{sigma}) to 14.4 ppt with an average value of 3.6 {+-} 2.3 ppt (1{sigma}, n = 72). The highest concentrations were found on the easternmost two transects just south of the equator. The average concentration of 3.6 ppt observed on this cruise is the lowest reported value for background atmospheric H{sub 2}S over the tropical oceans. A lack of correlation between {sup 222}Rn and H{sub 2}S in this region is in the range of 9 to 21 x 10{sup {minus}8} mol m{sup {minus}2} d{sup {minus}1}. From this flux the concentration of free sulfide (H{sub 2}S + S{sup 2{minus}}) in the surface mixed layer of the ocean is estimated to be in the range of 32 to 67 pmol L{sup {minus}1}. In the atmospheric the oxidation of H{sub 2}S produces SO{sub 2} at a rate of 2.1 to 4.4 x 10{sup {minus}11} mol m{sup {minus}3} d{sup {minus}1} which is only a small fraction of that estimated from the oxidation of dimethyl sulfide (DMS) in this region. A diurnal cycle was not observed in the H{sub 2}S data recorded during this cruise. 26 refs., 4 figs., 2 tabs.

Yvon, S.A.; Cooper, D.J.; Saltzman, E.S. [Univ. of Miami, FL (United States); Koropalov, V. [Univ. of Miami, FL (United States)]|[Institute of Applied Geophysics, Moscow (Russian Federation)

1993-09-20

260

Dynamics and hydrogen bonding in liquid ethanol  

NASA Astrophysics Data System (ADS)

Molecular dynamics simulations of liquid ethanol at three temperatures have been carried out. The hydrogen bonding states of ethanol molecules have been characterized by the number of hydrogen bonds in which the molecules participate. It is observed that the mean lifetimes of molecules in each hydrogen bonding state are markedly dependent on the temperature. Moreover, molecules with one hydrogen bond are more stable when they are donors than when they are acceptors. The dependence of the reorientational correlation functions on the hydrogen bonding state of molecules has been studied carefully. The decay of these functions is slower for molecules with higher numbers of hydrogen bonds and also becomes slower as temperature decreases. The relaxation for molecules with only one hydrogen bond is faster for those acting as proton donors than for those acting as proton acceptors. Finally, the results obtained by computer simulation are compared with those from recent measurements of the frequency-dependent dielectric permittivity of liquid ethanol.

Saiz, L.; Padro, J. A.; Guardia, E.

261

Direct Chlorination Process for geothermal power plant off-gas - hydrogen sulfide abatement  

SciTech Connect

The Direct Chlorination Process removes hydrogen sulfide from geothermal off-gases by reacting hydrogen sulfide with chlorine in the gas phase. Hydrogen chloride and elemental sulfur are formed by this reaction. The Direct Chlorination Process has been successfully demonstrated by an on-site operation of a pilot plant at the 3 M We HPG-A geothermal power plant in the Puna District on the island of Hawaii. Over 99.5% hydrogen sulfide removal was achieved in a single reaction stage. Chlorine gas did not escape the pilot plant, even when 90% excess chlorine gas was used. A preliminary economic evaluation of the Direct Chlorination Process indicates that it is very competitive with the Stretford Process Compared to the Stretford Process, the Direct Chlorination process requires about one-third the initial capital investment and about one-fourth the net daily expenditure. Because of the higher cost of chemicals and the restricted markets in Hawaii, the economic viability of this process in Hawaii is questionable.

Sims, A.V.

1983-06-01

262

Interaction of hydrogen with metal sulfide catalysts - direct observation of spillover  

SciTech Connect

A combination of controlled-atmosphere electron microscopy and in-situ electron diffraction techniques have been used to study the manner by which certain metal sulfides interact with 0.2 Torr hydrogen. In these experiments single crystal graphite was used as a probe material since its reactivity in both molecular and atomic hydrogen is well characterized. When the metal sulfide was in direct contact or physically separated from the graphite probe, pitting of the basal plane regions was observed even at room temperature. This unusual behavior is believed to result from the action of atomic hydrogen which is produced via reversible dissociation of molecular hydrogen on the metal sulfide particles. These species are extremely reactive towards the [pi]-electrons present on the graphite basal planes and this action leads to the creation of pits. At the low pressures used in this work, it is clear that the atomic species can migrate not only by surface diffusion processes (spillover) but also by transport through the gas phase. 30 refs., 7 figs., 1 tab.

Rodriguez, N.M.; Baker, R.T.K. (Auburn Univ., AL (United States))

1993-04-01

263

Feasibility study on high-temperature sorption of hydrogen sulfide by natural soils.  

PubMed

In this study, seven natural soils were tested for the sorption of hydrogen sulfide from coal gasification gas at high temperature. Results indicate that the LP natural soil has the best performance and the highest sulfur sorption capacity. After extracting free iron oxides, most natural soils have no sorption efficiency. The free iron oxides, therefore, proved to be the major components that react with hydrogen sulfide to form iron sulfides. The sulfur sorption capacity, either determined by EA or breakthrough time, is very close to the theoretical value based on the stoichiometric calculation with the content of free iron oxides. Moreover, the presence of CO is a positive effect while H2 is a negative effect. This can be explained via the water-shift reaction. On the basis of the results of temperature-programmed sulfidation (TPS), the starting temperature for the sorption of hydrogen sulfide is between 623-673 K. From the analyses of temperature-programmed oxidation (TPO) and XPS, the iron polysulfides are the major products and approximately 90% regeneration efficiency can be theoretically achieved while the temperature is controlled higher than 813 K. In the regeneration tests, the results show that the LP natural soil can be regenerated and thus reused after the oxidation process. No significant degeneration occurs on the LP natural soil after five sorption/regeneration cycles. The sulfur sorption capacity of the tenth regenerated soil can be achieved at least 80% compared to the fresh one. The experimental analyzed SO2 concentration from the regeneration process is almost identical to the theoretical calculated equilibrium concentration of the process. Maghemite is the main product after the regeneration process. PMID:16527331

Ko, Tzu-Hsing; Chu, Hsin; Tseng, Jeou-Jen

2006-08-01

264

Durable regenerable sorbent pellets for removal of hydrogen sulfide from coal gas  

DOEpatents

Pellets for removing hydrogen sulfide from a coal gasification stream at an elevated temperature are prepared in durable form, usable over repeated cycles of absorption and regeneration. The pellets include a material reactive with hydrogen sulfide, in particular zinc oxide, a binder, and an inert material, in particular calcium sulfate (drierite), having a particle size substantially larger than other components of the pellets. A second inert material and a promoter may also be included. Preparation of the pellets may be carried out by dry, solid-state mixing of components, moistening the mixture, and agglomerating it into pellets, followed by drying and calcining. Pellet size is selected, depending on the type of reaction bed for which the pellets are intended. The use of inert material with a large particle size provides a stable pellet structure with increased porosity, enabling effective gas contact and prolonged mechanical durability.

Siriwardane, R.V.

1999-02-02

265

Durable regenerable sorbent pellets for removal of hydrogen sulfide from coal gas  

DOEpatents

Pellets for removing hydrogen sulfide from a coal gasification stream at an elevated temperature are prepared in durable form usable over repeated cycles of absorption and regeneration. The pellets include a material reactive with hydrogen sulfide, in particular zinc oxide, a binder, and an inert material, in particular calcium sulfate (drierite), having a particle size substantially larger than other components of the pellets. A second inert material and a promoter may also be included. Preparation of the pellets may be carried out by dry, solid-state mixing of components, moistening the mixture, and agglomerating it into pellets, followed by drying and calcining. Pellet size is selected, depending on the type of reaction bed for which the pellets are intended. The use of inert material with a large particle size provides a stable pellet structure with increased porosity, enabling effective gas contact and prolonged mechanical durability.

Siriwardane, Ranjani V. (Morgantown, WV) [Morgantown, WV

1997-01-01

266

Durable regenerable sorbent pellets for removal of hydrogen sulfide from coal gas  

DOEpatents

Pellets for removing hydrogen sulfide from a coal gasification stream at an elevated temperature are prepared in durable form usable over repeated cycles of absorption and regeneration. The pellets include a material reactive with hydrogen sulfide, in particular zinc oxide, a binder, and an inert material, in particular calcium sulfate (drierite), having a particle size substantially larger than other components of the pellets. A second inert material and a promoter may also be included. Preparation of the pellets may be carried out by dry, solid-state mixing of components, moistening the mixture, and agglomerating it into pellets, followed by drying and calcining. Pellet size is selected, depending on the type of reaction bed for which the pellets are intended. The use of inert material with a large particle size provides a stable pellet structure with increased porosity, enabling effective gas contact and prolonged mechanical durability.

Siriwardane, R.V.

1997-12-30

267

Durable regenerable sorbent pellets for removal of hydrogen sulfide coal gas  

DOEpatents

Pellets for removing hydrogen sulfide from a coal gasification stream at an elevated temperature are prepared in durable form, usable over repeated cycles of absorption and regeneration. The pellets include a material reactive with hydrogen sulfide, in particular zinc oxide, a binder, and an inert material, in particular calcium sulfate (drierite), having a particle size substantially larger than other components of the pellets. A second inert material and a promoter may also be included. Preparation of the pellets may be carried out by dry, solid-state mixing of components, moistening the mixture, and agglomerating it into pellets, followed by drying and calcining. Pellet size is selected, depending on the type of reaction bed for which the pellets are intended. The use of inert material with a large particle size provides a stable pellet structure with increased porosity, enabling effective gas contact and prolonged mechanical durability.

Siriwardane, Ranjani V. (Morgantown, WV)

1999-01-01

268

Hydrogen sulfide removal from coal gas by the metal-ferrite sorbents made from the heavy metal wastewater sludge  

Microsoft Academic Search

The metal-ferrite (chromium-ferrite and zinc-ferrite) sorbents made from the heavy metal wastewater sludge have been developed for the hydrogen sulfide removal from coal gas. The high temperature absorption of hydrogen sulfide from coal gas with the metal-ferrite sorbent in a fixed bed reactor was conducted in this study. The metal-ferrite powders were the products of the ferrite process for the

Ting Ke Tseng; Han Ching Chang; Hsin Chu; Hung Ta Chen

2008-01-01

269

Computational prediction of hydrogen sulfide and methane separation at room temperature by anatase titanium dioxide  

NASA Astrophysics Data System (ADS)

Removal of hydrogen sulfide (H2S) is a key step for biogas purification. Herein, the adsorption of H2S and methane (CH4) on anatase titanium dioxide (TiO2) has been studied by first principle calculations. It is found that TiO2 offers excellent capacity for the H2S/CH4 separation. Using force-field molecular dynamics, this high separation capacity has been examined at room temperature.

Sun, Chenghua

2013-02-01

270

Inhibition of Hydrogen Sulfide Generation Contributes to 1-Methy-4-Phenylpyridinium IonInduced Neurotoxicity  

Microsoft Academic Search

Reactive oxygen species (ROS) overproduction contributes to the neurotoxicity of 1-methy-4-phenylpyridinium ion (MPP+). Increasing studies have shown that hydrogen sulfide (H2S) is an endogenous antioxidant gas. We have hypothesized that MPP+-caused neurotoxicity may involve the imbalance of proportion to this endogenous protective antioxidant gas. The aim of this\\u000a study is to evaluate whether MPP+ disturbs H2S synthesis in PC12 cells,

Xiao-Qing Tang; Li-Li Fan; Yu-Juan Li; Xin-Tian Shen; Yuan-Yuan Zhuan; Jian-Qin He; Jin-Hua Xu; Bi Hu; Yuan-Jian Li

2011-01-01

271

Role of endogenous hydrogen sulfide on renal damage induced by adriamycin injection  

Microsoft Academic Search

A single injection of adriamycin (ADR) induces marked and persistent proteinuria in rats that progress to glomerular and tubulointerstitial\\u000a lesions. It has been shown that ADR-induced nephrotoxicity is mediated, at least in part, by oxidative stress that lead to\\u000a inflammation. Endogenous hydrogen sulfide (H2S) is synthesized from l-cysteine and is an important signaling molecule in inflammation. This study evaluates the

Heloísa Della Coletta Francescato; Evelyn Cristina Santana Marin; Fernando de Queiroz Cunha; Roberto Silva Costa; Cleonice Giovanini Alves da Silva; Terezila Machado Coimbra

272

Support effect in hydrotreating catalysts: hydrogenation properties of molybdenum sulfide supported on ?-zeolites of various acidities  

Microsoft Academic Search

In order to better understand the role of the acidity of the support on the hydrogenation properties of a molybdenum sulfide phase, a ?-zeolite with a nominal Si\\/Al = 13.8 was partially (Si\\/Al = 15.0 and 18.7) and fully dealuminated (Si\\/Al ?800, no Brönsted acidity). To achieve a reasonable Mo loading with a high Mo dispersion, the Mo\\/? catalysts were prepared by

Claude-Emmanuel Hédoire; Catherine Louis; Anne Davidson; Michèle Breysse; Françoise Maugé; Michel Vrinat

2003-01-01

273

Reaction of 2-methyl-1,3-dioxolane with hydrogen sulfide  

Microsoft Academic Search

1.The reaction between 2-methyl-1,3-dioxolane and hydrogen sulfide in the presence of acid catalysts (HCl, p-toluenesulfonic acid, ZnCl2) leads to the formation of trithioacetaldehyde.2.A study of the reaction of 2-methyl-1,3-dioxolane with HCl gives reason to believe that in the first step of the thiolysis the HCl reacts with the cyclic acetal to form the unstablea-chloro ether.

M. F. Shostakovskii; A. S. Atabin; B. A. Trofimov; A. V. Gusarov

1965-01-01

274

Charge-Transfer Spectra of Iodine with Hydrogen Sulfide and Benzene in Low-Temperature Matrices  

Microsoft Academic Search

The absorption spectrum of benzene–iodine and hydrogen sulfide–iodine was studied at 20°K in argon, krypton, xenon, methane, nitrogen, and sulfur hexafluoride in the spectral range of 2300 to 4500 Å. In addition to the component spectra, strong bands were observed around 2800 Å in all solvents. They are assigned to the electronic charge-transfer transitions of the electron donor-acceptor systems benzene–iodine

E. M. Voigt; Beat Meyer

1968-01-01

275

Protective Role of Hydrogen Sulfide against Noise-Induced Cochlear Damage: A Chronic Intracochlear Infusion Model  

Microsoft Academic Search

BackgroundA reduction in cochlear blood flow plays an essential role in noise-induced hearing loss (NIHL). The timely regulation of cochlear perfusion determines the progression and prognosis of NIHL. Hydrogen sulfide (H2S) has attracted increasing interest as a vasodilator in cardiovascular systems. This study identified the role of H2S in cochlear blood flow regulation and noise protection.Methodology\\/Principal FindingsThe gene and protein

Xu Li; Xiao-Bo Mao; Ren-Yi Hei; Zhi-Bin Zhang; Li-Ting Wen; Peng-Zhi Zhang; Jian-Hua Qiu; Li Qiao

2011-01-01

276

Comparative study of using different materials as bacterial carriers to treat hydrogen sulfide  

Microsoft Academic Search

The use of support media for the immobilization of microorganisms is widely known to provide a surface for microbial growth\\u000a and protect the microorganisms from inhibitory compounds. In this study, molecular sieve, granular porous carbon, and ferric\\u000a oxide desulfurizer, immobilized with autotrophic bacteria capable of oxidizing ferrous iron to ferric iron, were developed\\u000a to treat hydrogen sulfide (H2S). Their corresponding

Zhiling Li; Tonghua Sun; Nanwen Zhu; Xinde Cao; Jinping Jia

2008-01-01

277

Laboratory Validation of a Passive Length-of-Stain Dosimeter for Hydrogen Sulfide  

Microsoft Academic Search

A direct reading, passive, length-of-stain, personal dosimeter has been developed for hydrogen sulfide (H2S). The dosimeter consists of a 5-mm ID, sealed glass tube about 130?mm long. Inside the sealed glass tube is a length of impregnated paper about 70?mm long. To use the dosimeter, one end of the tubing is broken off and the tube is inserted into a

ELMER S. McKEE; PAUL W. McCONNAUGHEY

1986-01-01

278

Influence of Gas Composition on Hydrogen Sulfide Removal at Moderate Temperature  

Microsoft Academic Search

The influence of gas composition on hydrogen sulfide removal from coal gas by zinc oxide sorbent was investigated at moderate temperature using TG technique. It was found that the removal of H2S by ZnO can vary greatly depending on the gas composition. Addition of H2, H2O to the inlet gas stream could promote the reaction rate, whereas the desulfurization was

Hui-Ling Fan; Ju Shangguan; Li-Tong Liang; Fang Shen

2011-01-01

279

Fiber optic sensors using novel substrates for hydrogen sulfide determination by solid surface fluorescence  

Microsoft Academic Search

Two different fiber optic sensors were developed for the determination of hydrogen sulfide at ppb concentration levels; a probe-type fiber optic sensor coated with polyethylene oxide containing 0.5 M CdCl2 and a fiber optic sensor utilizing 0.5 M CdCl2-pretreated filter paper as solid substrate. In the first type, CdCl2–polyethyleneoxide (PEO) mixture was coated onto the tip of a fiber optic

Ahmet E Ero?lu; Mürvet Volkan; O. Yavuz Ataman

2000-01-01

280

Performance of biotrickling filters for hydrogen sulfide removal under starvation and shock loads conditions  

Microsoft Academic Search

In the industrial operation of biotrickling filters for hydrogen sulfide (H2S) removal, shock loads or starvation was common due to process variations or equipment malfunctions. In this study, effects\\u000a of starvation and shock loads on the performance of biotrickling filters for H2S removal were investigated. Four experiments were conducted to evaluate the changes of biomass and viable bacteria numbers\\u000a in

Lan-he Zhang; Xiu-li Meng; Ying Wang; Li-dan Liu

2009-01-01

281

Solubility of hydrogen sulfide in aqueous mixtures of monoethanolamine with N-methyldiethanolamine  

Microsoft Academic Search

Alkanolamine aqueous solutions are frequently used for the removal of acidic gases, such as CO[sub 2] and H[sub 2]S, from gas streams in the natural gas and synthetic ammonia industries and petroleum chemical plants. The solubilities of hydrogen sulfide in aqueous mixtures of monoethanolamine (MEA) with N-methyl-diethanolamine (MDEA) have been measured at 40, 60, 80, and 100C and at partial

Meng Hui Li; Keh Perng Shen

1993-01-01

282

Molecular simulation of the solubility and diffusion of carbon dioxide and hydrogen sulfide in polyethylene melts  

Microsoft Academic Search

We present molecular simulation results of solubility and self-diffusion of carbon dioxide and hydrogen sulfide in linear polyethylene melts. Simulations were carried out at 433?K and pressures in the range 0.1–10?MPa. Solubilities were computed using Monte Carlo simulations in the osmotic ensemble, with constant number of polymer chains, pressure, temperature and gases chemical potential. Diffusion coefficients were obtained from equilibrium

François Faure; Bernard Rousseau; V ´ eronique Lachet; Philippe Ungerer

2007-01-01

283

Hydrogen sulfide increases calcium-activated potassium (BK) channel activity of rat pituitary tumor cells  

Microsoft Academic Search

Hydrogen sulfide (H2S) is the third gasotransmitter found to be produced endogenously in living cells to exert physiological functions. Large\\u000a conductance (maxi) calcium-activated potassium channels (BK), which play an important role in the regulation of electrical\\u000a activity in many cells, are targets of gasotransmitters. We examined the modulating action of H2S on BK channels from rat GH3 pituitary tumor cells

Guzel F. Sitdikova; Thomas M. Weiger; Anton Hermann

2010-01-01

284

Solubility of stibnite in hydrogen sulfide solutions, speciation, and equilibrium constants, from 25 to 350°C  

Microsoft Academic Search

Solubility of stibnite (Sb 2 S 3 ) was measured in aqueous hydrogen sulfide solutions as a function of pH and total free sulfur (TFS) concentrations at 25, 90, 200, 275, and 350°C and at saturated vapor pressures. At 25 and 90°C and TFS 0.01 molal solubility is controlled by the thioantimonite complexes H 2 Sb 2 S o 4

Ralf E. Krupp

1988-01-01

285

Solubility of mixtures of hydrogen sulfide and carbon dioxide in aqueous N-methyldiethanolamine solutions  

Microsoft Academic Search

Aqueous solutions of alkanolamines are commonly used to strip acid gases (H[sub 2]S and CO[sub 2]) from streams contaminated with these components. The two most widely used amines are monoethanolamine (MEA) and diethanolamine (DEA). The solubilities of mixtures of hydrogen sulfide and carbon dioxide in a 35 wt% (3.04 kmol\\/m[sup 3]) aqueous solution of N-methyldiethanolamine at 40 and 100C have

Fang Yuan Jou; John J. Carroll; Alan E. Mather; Frederick D. Otto

1993-01-01

286

Experimental determination of hydrogen sulfide solubility data in aqueous alkanolamine solutions  

Microsoft Academic Search

A computer-operated static apparatus for the measurement of gas solubility data by the synthetic method was used for the experimental determination of hydrogen sulfide solubility data in aqueous N-methyldiethanolamine (MDEA), diethanolamine (DEA) solutions and aqueous solution of a mixture of MDEA\\/DEA. For these systems, measurements at 313 and 373K and pressures up to about 1.3MPa were performed. The experimental data

Réda Sidi-Boumedine; Sven Horstmann; Kai Fischer; Elise Provost; Walter Fürst; Jürgen Gmehling

2004-01-01

287

Middle-thermophilic sulfur-oxidizing bacteria Thiomonas sp. RAN5 strain for hydrogen sulfide removal  

Microsoft Academic Search

Hydrogen sulfide (H2S) is one of the most toxic and offensively odorous gases and is generated in anaerobic bioreactors. A middle-thermophilic sulfur-oxidizing bacterium (SOB), Thiomonas sp. strain RAN5, was isolated and applied for H2S removal from both artificial and anaerobically digested gas. When a bioreactor containing medium inoculated with RAN5 was aerated continuously with artificial gas (containing 100 ppm H2S)

Ryoki Asano; Kayako Hirooka; Yutaka Nakai

2012-01-01

288

Boron toxicity is alleviated by hydrogen sulfide in cucumber ( Cucumis sativus L.) seedlings  

Microsoft Academic Search

Boron (B) is an essential micronutrient for plants, which when occurs in excess in the growth medium, becomes toxic to plants.\\u000a Rapid inhibition of root elongation is one of the most distinct symptoms of B toxicity. Hydrogen sulfide (H2S) is emerging as a potential messenger molecule involved in modulation of physiological processes in plants. In the present\\u000a study, we investigated

Bao-Lan Wang; Lei Shi; Yin-Xing Li; Wen-Hao Zhang

2010-01-01

289

Solubility of mixtures of hydrogen sulfide and carbon dioxide in aqueous solutions of triethanolamine  

Microsoft Academic Search

Aqueous alkanolamine solutions are commonly used for the removal of HâS and COâ from natural gas streams. The solubility of mixtures of hydrogen sulfide and carbon dioxide in three triethanolamine solutions, (2.0, 3.5, and 5.0) mol\\/dm³, has been determined at temperatures of 50 C, 75 C, and 100 C at partial pressures up to 5,490 kPa.

Fang-Yuan Jou; Frederick D. Otto; Alan E. Mather

1996-01-01

290

Sodium Nitroprusside Potentiates Hydrogen-Sulfide- Induced Contractions in Body Wall Muscle From a Marine Worm  

Microsoft Academic Search

Hydrogen sulfide (H2S) at concentrations of about 0.05 to 1 mmol l1 appears to function as a gasotransmitter in vertebrates, analogous to nitric oxide (NO) and carbon monoxide (1-5), but the actions of H2S in invertebrate tissue have not been well studied. In this study, we investigated the role of H2S in modulating body wall muscle tone in the marine

DAVID JULIAN; JENNIFER STATILE; TROY A. ROEPKE; ALISSA J. ARP

2005-01-01

291

A newly isolated heterotrophic bacterium, Xanthomonas sp. DY44, to oxidize hydrogen sulfide to polysulfide  

Microsoft Academic Search

Summary A newly isolated heterotrophic bacterium,Xanthomonas sp. DY44, was found to be capable of oxidizing hydrogen sulfide (H2S). Cells made non-viable by heat treatment (120°C, 20 min) did not show H2S oxidation. However, both cells sterilized by ?-rays irradiation and cell-free extract oxidized H2S, suggesting the existence of the heat-labile intracellular enzymatic system for H2S oxidation. AsXanthomonas sp. DY44 exhibited

Kyeoung-suk Cho; Isao Kuniyosl-d; Mitsuyo Hirai; Makoto Shoda

1991-01-01

292

Adsorption of carbonyl sulfide from liquid hydrocarbons with activated alumina and other adsorbents  

Microsoft Academic Search

Contamination of Liquid hydrocarbon streams with carbonyl sulfide (COS) is not desirable; particularly in propylene. COS may poison the down stream polymerization catalyst. Thus, it is usually required to reduce the COS concentration to an extremely low level, e.g. 1 ppm or less, for polymer grade propylene. Many technologies generally available for sulfur removal, such as scrubbing and distillation are

P. K. T

1988-01-01

293

Naturally occurring vapor-liquid-solid (VLS) Whisker growth of germanium sulfide  

USGS Publications Warehouse

The first naturally occurring terrestrial example of vapor-liquid-solid (VLS) growth has been observed in condensates from gases released by burning coal in culm banks. Scanning electron microscopy, X-ray diffraction, and energy dispersive analysis indicate that the crystals consist of elongated rods (??? 100 ??m) of germanium sulfide capped by bulbs depleted in germanium. ?? 1974.

Finkelman, R. B.; Larson, R. R.; Dwornik, E. J.

1974-01-01

294

Production of hydrogen in non oxygen-evolving systems: co-produced hydrogen as a bonus in the photodegradation of organic pollutants and hydrogen sulfide  

SciTech Connect

This report was prepared as part of the documentation of Annex 10 (Photoproduction of Hydrogen) of the IEA Hydrogen Agreement. Subtask A of this Annex concerned photo-electrochemical hydrogen production, with an emphasis on direct water splitting. However, studies of non oxygen-evolving systems were also included in view of their interesting potential for combined hydrogen production and waste degradation. Annex 10 was operative from 1 March 1995 until 1 October 1998. One of the collaborative projects involved scientists from the Universities of Geneva and Bern, and the Federal Institute of Technology in Laussane, Switzerland. A device consisting of a photoelectrochemical cell (PEC) with a WO{sub 3} photoanode connected in series with a so-called Grazel cell (a dye sensitized liquid junction photovoltaic cell) was developed and studied in this project. Part of these studies concerned the combination of hydrogen production with degradation of organic pollutants, as described in Chapter 3 of this report. For completeness, a review of the state of the art of organic waste treatment is included in Chapter 2. Most of the work at the University of Geneva, under the supervision of Prof. J. Augustynski, was focused on the development and testing of efficient WO{sub 3} photoanodes for the photoelectrochemical degradation of organic waste solutions. Two types of WO{sub 3} anodes were developed: non transparent bulk photoanodes and non-particle-based transparent film photoanodes. Both types were tested for degradation and proved to be very efficient in dilute solutions. For instance, a solar-to-chemical energy conversion efficiency of 9% was obtained by operating the device in a 0.01M solution of methanol (as compared to about 4% obtained for direct water splitting with the same device). These organic compounds are oxidized to CO{sub 2} by the photocurrent produced by the photoanode. The advantages of this procedure over conventional electrolytic degradation are that much (an order of magnitude) less energy is required and that sunlight can be used directly. In the case of photoproduction of hydrogen, as compared to water splitting, feeding the anodic compartment of the PEC with an organic pollutant, instead of the usual supporting electrolyte, will bring about a substantial increase of the photocurrent at a given illumination. Thus, the replacement of the photo-oxidation of water by the photodegradation of organic waste will be accompanied by a gain in solar-to-chemical conversion efficiency and hence by a decrease in the cost of the photoproduced hydrogen. Taking into account the benefits and possible revenues obtainable by the waste degradation, this would seem to be a promising approach to the photoproduction of hydrogen. Hydrogen sulfide (H{sub 2}S) is another waste effluent requiring extensive treatment, especially in petroleum refineries. The so-called Claus process is normally used to convert the H{sub 2}S to elemental sulfur. A sulfur recovery process developed at the Florida Solar Energy Center is described briefly in Chapter 4 by Dr. C. Linkous as a typical example of the photoproduction of hydrogen in a non oxygen-evolving system. The encouraging results obtained in these investigations of photoelectrochemical hydrogen production combined with organic waste degradation, have prompted a decision to continue the work under the new IEA Hydrogen Agreement Annex 14, Photoelectrolytic Hydrogen Production.

Sartoretti, C. Jorand; Ulmann, M.; Augustynski, J. (Electrochemistry Laboratory, Department of Chemistry, University of Geneva (CH)); Linkous, C.A. (Florida Solar Energy Center, University of Central Florida (US))

2000-01-01

295

Ab initio intermolecular potential energy surface and thermophysical properties of hydrogen sulfide.  

PubMed

A six-dimensional potential energy hypersurface (PES) for two interacting rigid hydrogen sulfide molecules was determined from high-level quantum-mechanical ab initio computations. A total of 4016 points for 405 different angular orientations of two molecules were calculated utilizing the counterpoise-corrected supermolecular approach at the CCSD(T) level of theory and extrapolating the calculated interaction energies to the complete basis set limit. An analytical site-site potential function with eleven sites per hydrogen sulfide molecule was fitted to the interaction energies. The PES has been validated by computing the second pressure virial coefficient, shear viscosity, thermal conductivity and comparing with the available experimental data. The calculated values of volume viscosity were not used to validate the potential as the low accuracy of the available data precluded such an approach. The second pressure virial coefficient was evaluated by means of the Takahashi and Imada approach, while the transport properties, in the dilute limit, were evaluated by utilizing the classical trajectory method. In general, the agreement with the primary experimental data is within the experimental error for temperatures higher than 300 K. For lower temperatures the lack of reliable data indicates that the values of the second pressure virial coefficient and of the transport properties calculated in this work are currently the most accurate estimates for the thermophysical properties of hydrogen sulfide. PMID:21720616

Hellmann, Robert; Bich, Eckard; Vogel, Eckhard; Vesovic, Velisa

2011-08-14

296

Differential mechanisms underlying neuroprotection of hydrogen sulfide donors against oxidative stress.  

PubMed

This study investigated whether slow-releasing organic hydrogen sulfide donors act through the same mechanisms as those of inorganic donors to protect neurons from oxidative stress. By inducing oxidative stress in a neuronal cell line HT22 with glutamate, we investigated the protective mechanisms of the organic donors: ADT-OH [5-(4-hydroxyphenyl)-3H-1,2-dithiole-3-thione], the most widely used moiety for synthesizing slow-releasing hydrogen sulfide donors, and ADT, a methyl derivative of ADT-OH. The organic donors were more potent than the inorganic donor sodium hydrogensulfide (NaHS) in protecting HT22 cells against glutamate toxicity. Consistent with previous publications, NaHS partially restored glutamate-depleted glutathione (GSH) levels, protected HT22 from direct free radical damage induced by hydrogen peroxide (H2O2), and NaHS protection was abolished by a KATP channel blocker glibenclamide. However, neither ADT nor ADT-OH enhanced glutamate-depleted GSH levels or protected HT22 from H2O2-induced oxidative stress. Glibenclamide, which abolished NaHS neuroprotection against oxidative stress, did not block ADT and ADT-OH neuroprotection against glutamate-induced oxidative stress. Unexpectedly, we found that glutamate induced AMPK activation and that compound C, a well-established AMPK inhibitor, remarkably protected HT22 from glutamate-induced oxidative stress, suggesting that AMPK activation contributed to oxidative glutamate toxicity. Interestingly, all hydrogen sulfide donors, including NaHS, remarkably attenuated glutamate-induced AMPK activation. However, under oxidative glutamate toxicity, compound C only increased the viability of HT22 cells treated with NaHS, but did not further increase ADT and ADT-OH neuroprotection. Thus, suppressing AMPK activation likely contributed to ADT and ADT-OH neuroprotection. In conclusion, hydrogen sulfide donors acted through differential mechanisms to confer neuroprotection against oxidative toxicity and suppressing AMPK activation was a possible mechanism underlying neuroprotection of organic hydrogen sulfide donors against oxidative toxicity. PMID:23587562

Jia, Jia; Xiao, Yunqi; Wang, Wei; Qing, Lina; Xu, Yinxiu; Song, Heng; Zhen, Xuechu; Ao, Guizhen; Alkayed, Nabil J; Cheng, Jian

2013-06-01

297

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

PubMed

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 ?-, ?- and ?-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 could fuel further sulfate reduction and potentially stabilize the sulfidic OMZ waters. PMID:23990875

Schunck, Harald; Lavik, Gaute; Desai, Dhwani K; Großkopf, Tobias; Kalvelage, Tim; Löscher, Carolin R; Paulmier, Aurélien; Contreras, Sergio; Siegel, Herbert; Holtappels, Moritz; Rosenstiel, Philip; Schilhabel, Markus B; Graco, Michelle; Schmitz, Ruth A; Kuypers, Marcel M M; Laroche, Julie

2013-01-01

298

Hydrogen Sulfide Therapy Attenuates the Inflammatory Response in a Porcine Model of Myocardial Ischemia - Reperfusion Injury  

PubMed Central

Introduction Hydrogen sulfide (H2S) is produced endogenously in response to myocardial ischemia and thought to be cardioprotective. The mechanism underlying this protection has yet to be fully elucidated, but may be related sulfide’s ability to limit inflammation. This study investigates the cardioprotection provided by exogenous H2S, and its potential anti-inflammatory mechanism of action. Methods The mid-LAD coronary artery in 14 Yorkshire swine was acutely occluded for 60 minutes, followed by reperfusion for 120 minutes. Controls(7) received placebo, and treatment animals(7) received sulfide 10 minutes prior to and throughout reperfusion. Hemodynamic and functional measurements were obtained. Evans blue and TTC staining identified the area-at-risk and infarction. Coronary microvascular reactivity was assessed. Tissue was assayed for myeloperoxidase activity and pro-inflammatory cytokines. Results Pre-I/R hemodynamics were similar between groups, whereas post-I/R mean arterial pressure (mmHg) was reduced by 28.7±5.0 in controls vs. 6.7±6.2 in treatment animals (p=0.03). +LV dP/dt (mmHg/sec) was reduced by 1325±455 in controls vs. 416±207 in treatment animals (p=0.002). Segmental shortening in the area-at-risk was better in treatment animals. Infarct size (% of area-at-risk) in controls was 41.0±7.8% vs. 21.2±2.5% in the treated group (p=0.036). Tissue levels of IL-6, IL-8, and TNF? and MPO activity decreased in the treatment group. Treated animals demonstrated improved microvascular reactivity. Conclusions Therapeutic sulfide provides protection in response to I/R injury, improving myocardial function, reducing infarct size, and improving coronary microvascular reactivity, potentially through its anti-inflammatory properties. Exogenous sulfide may have therapeutic utility in clinical settings in which I/R injury is encountered.

Sodha, Neel R.; Clements, Richard T.; Feng, Jun; Liu, Yuhong; Bianchi, Cesario; Horvath, Eszter M.; Szabo, Csaba; Stahl, Gregory L.; Sellke, Frank W.

2009-01-01

299

Multicomponent sulfides as narrow gap hydrogen evolution photocatalysts.  

PubMed

A series of mixed crystals composed of Cu(2)ZnSnS(4), Ag(2)ZnSnS(4) and ZnS was prepared by co-precipitation of the corresponding metal ions in aqueous sodium sulfide followed by annealing in a sulfur atmosphere. Ideal solid solutions of Cu(2)ZnSnS(4) and Ag(2)ZnSnS(4) with a kesterite structure ((Cu(x)Ag(1-x))(2)ZnSnS(4) (0 ?x? 1)) were successfully obtained by this procedure, as confirmed by their X-ray diffraction (XRD) patterns and energy-diffuse X-ray (EDX) analyses. On the other hand, the solubility of ZnS in these kesterite compounds was found to be limited: the upper limit of the ratio of ZnS to (Cu(x)Ag(1-x))(2)ZnSnS(4) was less than 0.1, regardless of the Cu-Ag ratio in (Cu(x)Ag(1-x))(2)ZnSnS(4). Based on the results for dependence of their photoabsorption properties on atomic compositions, a plausible band structure is discussed. Evaluation of the photocatalytic activity for H(2) evolution of these mixed crystals from an aqueous solution containing S(2-) and SO(3)(2-) ions upon loading Ru catalysts under simulated solar radiation (AM 1.5) revealed that active compounds for this reaction should contain both dissolved ZnS and Ag components. The dissolved ZnS in (Cu(x)Ag(1-x))(2)ZnSnS(4) gave upward shifts of their conduction band edges. Moreover, the presence of Ag in the solid solution provided n-type conductivity, leading to efficient migration of photogenerated electrons to the surface to induce water reduction into H(2). PMID:20852813

Ikeda, Shigeru; Nakamura, Takayuki; Harada, Takashi; Matsumura, Michio

2010-11-14

300

Competition for Dimethyl Sulfide and Hydrogen Sulfide by Methylophaga sulfidovorans and Thiobacillus thioparus T5 in Continuous Cultures  

PubMed Central

Pure and mixed cultures of Methylophaga sulfidovorans and Thiobacillus thioparus T5 were grown in continuous cultures on either dimethyl sulfide, dimethyl sulfide and H(inf2)S, or H(inf2)S and methanol. In pure cultures, M. sulfidovorans showed a lower affinity for sulfide than T. thioparus T5. Mixed cultures, grown on dimethyl sulfide, showed coexistence of both species. M. sulfidovorans fully converted dimethyl sulfide to thiosulfate, which was subsequently further oxidized to sulfate by T. thioparus T5. Mixed cultures supplied with sulfide and methanol showed that nearly all the sulfide was used by T. thioparus T5, as expected on the basis of the affinities for sulfide. The sulfide in mixed cultures supplied with dimethyl sulfide and H(inf2)S, however, was used by both bacteria. This result may be explained by the fact that the H(inf2)S-oxidizing capacity of M. sulfidovorans remains fully induced by intracellular H(inf2)S originating from dimethyl sulfide metabolism.

De Zwart, J.; Sluis, J.; Kuenen, J. G.

1997-01-01

301

Production of Hydrogen by Superadiabatic Decomposition of Hydrogen Sulfide. Final Technical Report for the Period June 1, 1999-September 30, 2000.  

National Technical Information Service (NTIS)

The objective of this program is to develop an economical progress for hydrogen production, with no additional carbon dioxide emission, through the thermal decomposition of hydrogen sulfide (H2S) in H2S-rich waste streams to high-purity hydrogen and eleme...

R. B. Slimane F. S. Lau J. Abbasian

2000-01-01

302

Experimental studies of selective acid gas removal: Absorption of hydrogen sulfide and carbon dioxide into aqueous methyldiethanolamine using packed columns  

SciTech Connect

The use of aqueous methyldiethanolamine (MDEA) for selective removal of hydrogen sulfide from acid gas streams has been studied in a 2 inch column packed with 1/4 inch ceramic Intalox saddles. The column was operated in a counter-current, steady state fashion. The feed gas composition varied between 1 and 5 mole % hydrogen sulfide and between 0 and 50 mole % carbon dioxide. In order to assist the development of packed column absorption models, the rate at which pure carbon dioxide absorbs into 2 M MDEA was measured as a function of pressure, liquid flow rate and packed bed length. The importance of end effects was carefully evaluated. In addition, draining and tracer methods were used to estimate the amount of static holdup present in the column. Using classical draining methods, as much as 50 % of the total holdup was found to be static. However, according to the step decrease in tracer method, less than 5 % of the total holdup was static. Since the step decrease in tracer method measures the amount of static holdup present in the bed under irrigated conditions, it seems likely that the draining method provides an unrealistic estimate of static holdup. Thus, although the notion of static holdup may be useful as a means of correlating mass transfer coefficients, the data indicate that very little static holdup exists in the column under irrigated conditions. Hence, in the absence of a mechanistically sound model, the choice of whether to use static holdup or dispersion as a means of accounting for deviations from plug flow in the liquid phase should be made on the basis of computational convenience.

Schubert, C.N.

1988-01-01

303

Simultaneous absorption of carbon dioxide and hydrogen sulfide with carbonyl sulfide contamination in aqueous methyldiethanolamine  

SciTech Connect

The primary objectives of the research were to: (1) obtain experimental data for simultaneous gas absorption systems to help formulate and test theoretical models of multicomponent mass transfer, and (2) develop the theoretical models which predict mass transfer rates from chemical reaction kinetics, system hydrodynamics and boundary conditions. To fulfill these objectives two-phase contact devices were designed and constructed. These were, a solubility of equilibrium apparatus, a laminar liquid jet apparatus, and a wetted-sphere apparatus. These devices were used to measure fundamental physiochemical properties of gases in liquids. The properties measured were the solubilities and diffusivities of N{sub 2}O, CO{sub 2}, and COS in aqueous MDEA. The reaction rate constants of the reactions between CO{sub 2} and MDEA and between COS and MDEA were also measured. In addition to these devices, a stirred tank absorber was used to obtain experimental data on multicomponent simultaneous absorption. A computer program was developed to solve the two-point boundary value problems generated by film theory. This research involved modeling and analyzing gas absorption systems with the chemical reactions taken as irreversible in one case and reversible in another. A parametric study of the case of reversible reactions revealed that for certain ranges of the parameter space the model predicted forced desorption. The program was tested against experimental data from two simultaneous absorption experiments. These were the simultaneous absorption of CO{sub 2}, COS, and N{sub 2} into aqueous MDEA and the simultaneous absorption of CO{sub 2}, H{sub 2}S, COS and N{sub 2} into aqueous MDEA. The program predictions of gas absorption rates were within 13% of the experimental values for the former experiment and within 9% for the latter.

Al-Ghawas, H.A.

1988-01-01

304

OP011 Increased growth and germination success in plants following hydrogen sulfide administration.  

PubMed

The biological effects of hydrogen sulfide (H2S) have received increasing attention in recent years, not only as a putative kill mechanism during past mass extinctions, but also as an important signaling molecule in both aerobic and anaerobic organisms. Hydrogen sulfide has recently been added to nitric oxide (NO) and carbon monoxide (CO) as a newly categorized group of biologically active gases termed gasotransmitters and gasomediators. The origin of these dual activities remains unknown, but it may be that these varied signaling and biological mediating capabilities are remnants of biological responses by life either evolving or inhabiting highly sulfidic and anoxic environments of earlier times in Earth history. Today, H2S causes a wide variety of vital effects across the "Tree of Life", from metabolic inhibition, to energy source, to coordination of developmental growth programs in yeast and perhaps higher organisms as well. We report [1] that exposing either roots or seeds of multicellular plants to extremely low concentrations of dissolved hydrogen sulfide at any stage of life causes statistically significant increases in biomass including higher fruit yield. Individual cells in treated plants were smaller (?13%) than those of controls. Germination success and seedling size increased in, bean, corn, wheat, and pea seeds while time to germination decreases. Additionally, it was determined that at high concentrations (>10mM) it appears that photosystem (PS) II is inhibited whereas PSI remains active [2]. These findings indicated an important role of H2S as a signaling molecule that can increase the growth rate of all species yet tested. The increased crop yields reported here has the potential to effect the world's agricultural output. PMID:24948249

Dooley, Frederick D; Nair, Suven P; Ward, Peter D

2013-09-01

305

Characterization of the sulfur retained by soils exposed to hydrogen sulfide  

SciTech Connect

We recently reported studies showing that air-dry and moist soils have substantial capacities for sorption of hydrogen sulfide (H[sub 2]S) from air. Studies to characterize the S retained when air-dry and moist soils were exposed to air containing 2% H[sub 2]S showed that a large fraction (average 79%) of this S was in the form of elemental S (S[degrees]) and that very little (0.1% or less) was in the form of sulfide. The recovery of sorbed S as sulfate averaged 5.9% with the air-dry soils and 3.0% with the moist soils. The 42 soils used in this work were selected so that they differed markedly in physical and chemical properties. Statistical analyses of the relationships between these properties and the recovery of sorbed S as elemental S showed that this recovery was significantly correlated with the amount of soil Mn that was extractable by dithionite-citrite buffer. This suggests that Mn compounds in soils catalyze oxidation of sulfide-S to elemental-S when soils are exposed to air containing H[sub 2]S. 16 refs., 3 tabs.

Cihacek, L.J. (North Dakota State Univ., Fargo (United States)); Bremner, J.M. (Iowa State Univ., Ames (United States))

1993-01-01

306

Abundances of hydrogen sulfide in star-forming regions  

SciTech Connect

Interstellar H2S and its isotopic variant H2(S-34) have been observed toward several star-forming regions via their 1(10)-1(01) transitions at 2 mm, using the FCRAO telescope. In sources where both isotopic species were observed, column densities of about 10 to the 16th/sq cm were measured. Column density lower limits of about 10 to the 14th/sq cm for H2S were found for other sources, where only the main isotopic line was observed. The fractional abundances of H2S relative to molecular hydrogen appear to be enhanced by at least an order of magnitude relative to quiescent cloud values (about 10 to the -9th) for many of the observed sources. 28 refs.

Minh, Y.C.; Ziurys, L.M.; Irvine, W.M.; Mcgonagle, D. (Daeduk Radio Astronomy Observatory, Taejon (Republic of Korea) Arizona State Univ., Tempe (USA) Five College Radio Astronomy Observatory (USA) Massachusetts Univ., Amherst (USA))

1991-01-01

307

EP03 Therapeutic outlook for hydrogen sulfide donors.  

PubMed

Considerable evidence has accumulated in recent years suggesting that H2S, synthesised from l-cysteine via cystathionine ? lyase (CSE) or cystathionine ? synthase (CBS) or from 3-mercaptopyruvate via 3-mercaptopyruvate transferase (3-MST), plays a significant part in a range of physiological and/or pathophysiological processes. The possibility that either manipulating endogenous H2S biosynthesis or using H2S donor drugs may lead to new therapeutic entities was raised several years ago (e.g. [1]). Increasingly, H2S is being thought of as a cytoprotective agent which restores physiological function in diseased cells or organ systems and hence interest has centred on identifying novel H2S donors. To date, a number of H2S donors have been characterized. These include thiones such as 5-(p-hydroxyphenyl)-1,2-dithione-3-thione (ADT-OH), cysteine derivatives such as S-allylcysteine (SAC) and S-propargyl-cysteine (S-SPRC), GYY4137 (morpholin-4-ium 4 methoxyphenyl (morpholino) phosphinodithioate), H2S-releasing derivatives of non-steroidal anti-inflammatory drugs (NSAID) such as S-diclofenac and, recently, a nitric oxide (NO) and H2S-releasing derivative of aspirin. In addition, sulfide salts such as sodium hydrosulfide (NaHS) also release H2S. Other H2S-releasing drugs are no doubt in the pipeline. Potential applications of some or all of these compounds include such diverse conditions as hypertension, cardiac failure, ischemic reperfusion injury, acute and chronic inflammation, cancer and even to promote healthy aging. For example, GYY4137 reduces knee joint swelling in mice injected with Freund's adjuvant [2] and is anti-tumor in the mouse [3]. Thus, H2S donors have shown early promise in a range of therapeutic areas. The further development of H2S donors presents a number of difficulties. For example, equating plasma concentration of released H2S from such donors with biological activity in an animal model (or in man) is problematic since, not only is H2S rapidly metabolized to an array of products, but current techniques to measure the concentration of this endogenous gas are likely insufficiently sensitive or selective. In addition, efficacy would be better correlated with H2S concentration at the site where the gas produces its biological effect (not plasma) which may be extracellular or even intracellular perhaps close to or in mitochondria. Further work is also needed to assess the cell permeability of H2S donors in order to determine whether they 'carry' H2S into cells thereby 'loading' the cell with the gas. This presentation will provide an overview of the potential for H2S donors in the clinic. PMID:24948236

Moore, Philip K

2013-09-01

308

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

NASA Astrophysics Data System (ADS)

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 sp2 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 (NH2)NHdbnd CSO2H 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.

Zeng, Qunfeng; Yu, Fei; Dong, Guangneng; Mao, Junhong

2012-10-01

309

Development of Automotive Liquid Hydrogen Storage Systems  

NASA Astrophysics Data System (ADS)

Liquid hydrogen (LH2) takes up less storage volume than gas but requires cryogenic vessels. State-of-the-art applications for passenger vehicles consist of double-wall cylindrical tanks that hold a hydrogen storage mass of up to 10 kg. The preferred shell material of the tanks is stainless steel, since it is very resistant against hydrogen brittleness and shows negligible hydrogen permeation. Therefore, the weight of the whole tank system including valves and heat exchanger is more than 100 kg. The space between the inner and outer vessel is mainly used for thermal super-insulation purposes. Several layers of insulation foils and high vacuums of 10-3 Pa reduce the heat entry. The support structures, which keep the inner tank in position to the outer tank, are made of materials with low thermal conductivity, e.g. glass or carbon fiber reinforced plastics. The remaining heat in-leak leads to a boil-off rate of 1 to 3 percent per day. Active cooling systems to increase the stand-by time before evaporation losses occur are being studied. Currently, the production of several liquid hydrogen tanks that fulfill the draft of regulations of the European Integrated Hydrogen Project (EIHP) is being prepared. New concepts of lightweight liquid hydrogen storage tanks will be investigated.

Krainz, G.; Bartlok, G.; Bodner, P.; Casapicola, P.; Doeller, Ch.; Hofmeister, F.; Neubacher, E.; Zieger, A.

2004-06-01

310

Sulfide chemiluminescence detection  

Microsoft Academic Search

A method of chemiluminescently determining a sulfide which is either hydrogen sulfide or methyl mercaptan by reacting the sulfide with chlorine dioxide at low pressure and under conditions which allow a longer reaction time in emission of a single photon for every two sulfide containing species, and thereafter, chemiluminescently detecting and determining the sulfide. The invention also relates not only

Stanford R. Spurlin; Edward S. Yeung

1985-01-01

311

Sulfide chemiluminescence detection  

Microsoft Academic Search

A method is described for chemiluminescently determining a sulfide which is either hydrogen sulfide or methyl mercaptan by reacting the sulfide with chlorine dioxide at low pressure and under conditions which allow a longer reaction time in emission of a single photon for every two sulfide containing species, and thereafter, chemiluminescently detecting and determining the sulfide. The invention also relates

S. R. Spurlin; E. S. Yeung

1985-01-01

312

Rotational spectroscopic study of carbonyl sulfide solvated with hydrogen molecules  

NASA Astrophysics Data System (ADS)

Rotational spectra of small-sized (H2)N-OCS clusters with N=2-7 were measured using a pulsed-jet Fourier transform microwave spectrometer. These include spectra of pure (para-H2)N-OCS clusters, pure (ortho-H2)N-OCS clusters, and mixed ortho-H2 and para-H2 containing clusters. The rotational lines of ortho-H2 molecules containing clusters show proton spin-proton spin hyperfine structure, and the pattern evolves as the number of ortho-H2 molecules in the cluster increases. Various isotopologues of the clusters were investigated, including those with O13CS, OC33S, OC34S, and O13C34S. Nuclear quadrupole hyperfine structures of rotational transitions were observed for 33S (nuclear spin quantum number I=3/2) containing isotopologues. The 33S nuclear quadrupole coupling constants are compared to the corresponding constant of the OCS monomer and those of the HeN-OCS clusters. The assignment of the number of solvating hydrogen molecules N is supported by the analyses of the proton spin-proton spin hyperfine structures of the mixed clusters, the dependence of line intensities on sample conditions (pressure and concentrations), and the agreement of the (para-H2)N-OCS and (ortho-H2)N-OCS rotational constants with those from a previous infrared study [J. Tang and A. R. W. McKellar, J. Chem. Phys. 121, 3087 (2004)].

Michaud, Julie M.; Jäger, Wolfgang

2008-10-01

313

Modeling leaks from liquid hydrogen storage systems.  

SciTech Connect

This report documents a series of models for describing intended and unintended discharges from liquid hydrogen storage systems. Typically these systems store hydrogen in the saturated state at approximately five to ten atmospheres. Some of models discussed here are equilibrium-based models that make use of the NIST thermodynamic models to specify the states of multiphase hydrogen and air-hydrogen mixtures. Two types of discharges are considered: slow leaks where hydrogen enters the ambient at atmospheric pressure and fast leaks where the hydrogen flow is usually choked and expands into the ambient through an underexpanded jet. In order to avoid the complexities of supersonic flow, a single Mach disk model is proposed for fast leaks that are choked. The velocity and state of hydrogen downstream of the Mach disk leads to a more tractable subsonic boundary condition. However, the hydrogen temperature exiting all leaks (fast or slow, from saturated liquid or saturated vapor) is approximately 20.4 K. At these temperatures, any entrained air would likely condense or even freeze leading to an air-hydrogen mixture that cannot be characterized by the REFPROP subroutines. For this reason a plug flow entrainment model is proposed to treat a short zone of initial entrainment and heating. The model predicts the quantity of entrained air required to bring the air-hydrogen mixture to a temperature of approximately 65 K at one atmosphere. At this temperature the mixture can be treated as a mixture of ideal gases and is much more amenable to modeling with Gaussian entrainment models and CFD codes. A Gaussian entrainment model is formulated to predict the trajectory and properties of a cold hydrogen jet leaking into ambient air. The model shows that similarity between two jets depends on the densimetric Froude number, density ratio and initial hydrogen concentration.

Winters, William Stanley, Jr.

2009-01-01

314

Green Synthesis of Dichlorophenylphosphine Sulfide Using Chloroaluminate Ionic Liquids as a Catalyst  

Microsoft Academic Search

Triethylhydrogenammonium chloride-XAlCl3 Ionic Liquids (ILs) were used as a catalyst for the clean synthesis of dichlorophenylphosphine sulfide. Two synthesis routes were investigated; one of them was a reaction of sulfur and Dichlorophenylphosphine (DCPP), and another was a one-pot reaction of benzene, phosphorus, chloride, and sulfur. Effects of the ILs composition and reaction time and the quantity of the ILs on

Li-Sheng Wang; Hui-Bao Kang; Zhong-Wei Wang; Chong-Gang Wang

2007-01-01

315

Hydrogen sulfide enhances alfalfa ( Medicago sativa ) tolerance against salinity during seed germination by nitric oxide pathway  

Microsoft Academic Search

Aims and methods  The molecular mechanisms and signal transduction pathways of hydrogen sulfide (H2S) in plant biology are still unclear. Here, by using pharmacological and biochemical approaches, we report that H2S promotes germination and alleviates salinity damage involving nitric oxide (NO) pathway.\\u000a \\u000a \\u000a \\u000a \\u000a Results  Upon 100 mM NaCl treatment, both H2S donor sodium hydrosulfide (NaHS) and NO donor sodium nitroprusside (SNP) at 100 ?M could

Yanqin Wang; Le Li; Weiti Cui; Sheng Xu; Wenbiao Shen; Ren Wang

316

Solubility of mixtures of hydrogen sulfide and carbon dioxide in aqueous N-methyldiethanolamine solutions  

SciTech Connect

Aqueous solutions of alkanolamines are commonly used to strip acid gases (H[sub 2]S and CO[sub 2]) from streams contaminated with these components. The two most widely used amines are monoethanolamine (MEA) and diethanolamine (DEA). The solubilities of mixtures of hydrogen sulfide and carbon dioxide in a 35 wt% (3.04 kmol/m[sup 3]) aqueous solution of N-methyldiethanolamine at 40 and 100C have been measured. Partial pressures of the acid gases ranged from 0.006 to 101 kPa at 40C and from 4 to 530 kPa at 100C.

Jou, Fang Yuan; Carroll, J.J.; Mather, A.E.; Otto, F.D. (Univ. of Alberta, Edmonton, Alberta (Canada). Dept. of Chemical Engineering)

1993-01-01

317

Passivity of corrosion-resistant alloys in environments containing chloride and hydrogen sulfide  

SciTech Connect

Passivity of corrosion-resistance alloys (CRA) in chloride (Cl{sup {minus}}) + hydrogen sulfide (H{sub 2}S) environments was investigated electrochemically to clarify the role of alloying elements. Pitting potential (V{prime}c) was correlated with alloying elements of Ni, Cr, and Mo. Ni was shown ineffective in improving pitting resistance in Cl{sup {minus}} environments. Passivity in Cl{sup {minus}} + H{sub 2}S environments was discussed based upon Auger electron spectroscopy (AES) analysis, and the roles of each alloying element were clarified.

Denpo, K.; Ogawa, H. [Nippon Steel Corp., Futtsu, Chiba (Japan). Pipe and Tube Steel Research Labs.

1997-09-01

318

Novel Composite Hydrogen-Permeable Membranes for Non-Thermal Plasma Reactors for the Decomposition of Hydrogen Sulfide. Annual Report, October 1, 2004-September 30, 2005.  

National Technical Information Service (NTIS)

The goal of this experimental project is to design and fabricate a reactor and membrane test cell to dissociate hydrogen sulfide (H2S) in a non-thermal plasma and recover hydrogen (H2) through a superpermeable multi-layer membrane. Superpermeability of hy...

M. D. Argyle J. F. Ackerman S. Muknahallipatna J. C. Hamann S. Legowski

2005-01-01

319

Effect of hydrogen sulfide on aqueous corrosion of commercially pure Al 99.5  

SciTech Connect

Recently, there has been interest in the use of aluminum alloys as possible alternatives to carbon steel for handling oilfield products, such as brines with dissolved carbon dioxide (CO{sub 2}) and H{sub 2}S. The effect of hydrogen sulfide on the corrosion behavior of commercially pure aluminum (DIN Al 99.5 [AA 1050A]) in chloride solutions containing carbon dioxide, bicarbonate, and copper ions at 30 C and 80 C was investigated using natural immersion corrosion tests, cathodic polarization, and scanning electron microscopy. The highest corrosion rates were observed in solutions containing Cu{sup 2+} but with no H{sub 2}S content because of copper deposition on the metal surface. Significant pitting occurred at 80 C. With H{sub 2}S in the solution, pitting corrosion was eliminated by removal of Cu{sup 2+} and other deleterious heavy-metal ion impurities form the solution in the form of insoluble sulfides. If H{sub 2}S was introduced after the copper deposited on the aluminum surface, no inhibiting effect was detected at 30 C, but a degree of inhibition still was observed at 80 C, presumably because the deposited copper was converted more effectively into copper sulfide at the higher temperature.

Bjoergum, A.; Sigurdsson, H. [SINTEF Corrosion Center, Trondheim (Norway); Nisancioglu, K. [Norwegian Inst. of Tech., Trondheim (Norway). Dept. of Electrochemistry

1995-08-01

320

High Efficient Cryocooler for Liquid Hydrogen System  

NASA Astrophysics Data System (ADS)

Conversion into Hydrogen Energy Society is advanced focusing on the application to a fuel cell electric vehicle. As volume and weight density of liquid hydrogen are large, it is the method which was most excellent as the storage method of hydrogen. However, in order to store liquid hydrogen stably over a long period of time, decreasing the loss of energy, development of an efficient small cryocooler becomes important. This paper reports the research about improvement in the refrigeration efficiency of a two-stage GM cryocooler. In order that the GM cryocooler may operate by the Simon expansion, it carries out asymptotic of the COP of the GM cryocooler to the Carnot COP as a compression ratio is lowered. When experimented based on this view, it was checked that refrigeration efficiency rises with reduction in a compression ratio. Furthermore, if the compression ratio is lowered, refrigeration efficiency will fall rapidly. The peak value of the refrigeration efficiency in 20K level attained 28%Carnot. It was verified by optimization of the compression ratio of the GM cryocooler that refrigeration efficiency can be improved significantly. Therefore, sharp reduction of the energy consumption of a liquid hydrogen system will be attained by applying the result of this research.

Nakagome, H.

2006-04-01

321

Liquid Hydrogen Consumption During Space Shuttle Program  

NASA Technical Reports Server (NTRS)

This slide presentation reviews the issue of liquid hydrogen consumption and the points of its loss in prior to the shuttle launch. It traces the movement of the fuel from the purchase to the on-board quantity and the loss that results in 54.6 of the purchased quantity being on board the Shuttle.

Partridge, Jonathan K.

2011-01-01

322

Modeling the Space Shuttle Liquid Hydrogen Subsystem.  

National Technical Information Service (NTIS)

This paper describes experiences with modeling the liquid hydrogen subsystem of the space shuttle. The Symbolic Model Verifier tool and the Software Cost Reduction tool set were used to model and specify the behavior of the system. The tools were then use...

B. Atanacio

2000-01-01

323

Liquid Hydrogen Target Experience at SLAC.  

National Technical Information Service (NTIS)

Liquid hydrogen targets have played a vital role in the physics program at SLAC for the past 40 years. These targets have ranged from small 'beer can' targets to the 1.5 m long E158 target that was capable of absorbing up to 800 W without any significant ...

J. G. Weisend R. Boyce A. Candia W. Kaminskas J. Mark

2005-01-01

324

An approach to global rovibrational analysis based on anharmonic ladder operators: Application to hydrogen selenide and hydrogen sulfide  

NASA Astrophysics Data System (ADS)

A formalism to model the ro-vibrational spectrum of triatomic asymmetric top molecules is presented. The quantum mechanical ro-vibrational kinetic and potential energy function is considered as a Taylor expansion in internal coordinates of Morse local oscillators. Thereafter, local Morse coordinates and momenta are expanded in terms of Morse Potential ladder operators. Only polyad-conserving terms are considered. Expansions of the kinetic and potential energies of the ro-vibrational Hamiltonian are considered up to sextic terms. The resulting Hamiltonian was diagonalized using a symmetry-adapted basis, generated by the eigenfunction method ( J.Q.Chen, Group Representation Theory for Physicists,World Scientific, 1989; R. Lemus, 2003 Mol.Phys., 101 2511-2528.). The model is applied to hydrogen sulfide (H_2S) and hydrogen selenide (H_2Se).

Perez-Bernal, F.; Carvajal, M.; Alvarez-Bajo, O.

2011-05-01

325

Role of ryanodine receptors in the effects of hydrogen sulfide on transmitter release from the frog motor nerve ending.  

PubMed

We studied the role of ryanodine receptors in the effects of hydrogen sulfide on transmitter release from frog motor nerve ending. Sodium hydrosulfide (300 ?M), a donor of hydrogen sulfide, reversibly increased the frequency of miniature endplate current without changes in its amplitude-time parameters. These effects were associated with reversible increase in endplate current amplitude, which was abolished by activation of ryanodine receptors of intracellular Ca(2+)stores with caffeine (3 mM) and ryanodine (0.5 ?M). Under conditions of ryanodine receptors blockade with ryanodine (10 ?M), sodium hydrosulfide had no effect on induced transmitter release, but its effects remained unchanged during ryanodine receptors blockade with dantrolene (25 ?M). We concluded that an enhanced acetylcholine release induced by hydrogen sulfide is related to an increase of intracellular Ca(2+)concentration due to activation of ryanodine receptors for intracellular Ca(2+)-pool. PMID:23667860

Gerasimova, E V; Yakovleva, O V; Zefirov, A L; Sitdikova, G F

2013-05-01

326

Purification, crystallization and preliminary X-ray analysis of two hydrogen sulfide-producing enzymes from Fusobacterium nucleatum.  

PubMed

Hydrogen sulfide produced by oral bacteria is responsible for oral malodour. Two homologous hydrogen sulfide-producing enzymes, Fn1220 and Cdl, from Fusobacterium nucleatum (which actively produces hydrogen sulfide) were overproduced, purified and crystallized. X-ray diffraction data were collected from the crystals using a synchrotron-radiation source. The Fn1220 crystal belonged to tetragonal space group P4(1)2(1)2 or P4(3)2(1)2 (unit-cell parameters a=b=116.8, c=99.2?Å) and the Cdl crystal belonged to monoclinic space group P2(1) (unit-cell parameters a=84.9, b=70.9, c=87.6?Å, ?=90.3°). PMID:23192034

Kezuka, Yuichiro; Abe, Naoto; Yoshida, Yasuo; Nonaka, Takamasa

2012-12-01

327

Liquid Hydrogen Sensor Considerations for Space Exploration  

NASA Technical Reports Server (NTRS)

The on-orbit management of liquid hydrogen planned for the return to the moon will introduce new considerations not encountered in previous missions. This paper identifies critical liquid hydrogen sensing needs from the perspective of reliable on-orbit cryogenic fluid management, and contrasts the fundamental differences in fluid and thermodynamic behavior for ground-based versus on-orbit conditions. Opportunities for advanced sensor development and implementation are explored in the context of critical Exploration Architecture operations such as on-orbit storage, docking, and trans-lunar injection burn. Key sensing needs relative to these operations are also examined, including: liquid/vapor detection, thermodynamic condition monitoring, mass gauging, and leak detection. Finally, operational aspects of an integrated system health management approach are discussed to highlight the potential impact on mission success.

Moran, Matthew E.

2006-01-01

328

Tungsten sulfide enhancing solar-driven hydrogen production from silicon nanowires.  

PubMed

Tungsten sulfides, including WS2 (crystalline) and WS3 (amorphous), were introduced to silicon nanowires, and both can promote the photoelectrochemical hydrogen production of silicon nanowires. In addition, more enhancement of energy conversion efficiency can be achieved by the loading of WS3, in comparison with loading of WS2. Polarization curves of WS3 and WS2 suggest that WS3 has higher catalytic activity in the hydrogen evolution reaction than WS2, affording higher energy conversion efficiency in silicon nanowires decorated with WS3. The higher electrocatalytic activity of WS3 correlates with the amorphous structure of WS3 and larger surface area of WS3, which result in more active sites in comparison with crystalline WS2. PMID:24905279

Huang, Zhipeng; Wang, Chifang; Chen, Zhibo; Meng, Hua; Lv, Cuncai; Chen, Zhongzhong; Han, Ruqu; Zhang, Chi

2014-07-01

329

Electrodeposited cobalt-sulfide catalyst for electrochemical and photoelectrochemical hydrogen generation from water.  

PubMed

A cobalt-sulfide (Co-S) film prepared via electrochemical deposition on conductive substrates is shown to behave as an efficient and robust catalyst for electrochemical and photoelectrochemical hydrogen generation from neutral pH water. Electrochemical experiments demonstrate that the film exhibits a low catalytic onset overpotential (?) of 43 mV, a Tafel slope of 93 mV/dec, and near 100% Faradaic efficiency in pH 7 phosphate buffer. Catalytic current densities can approach 50 mA/cm(2) and activity is maintained for at least 40 h. The catalyst can also be electrochemically coated on silicon, rendering a water-compatible photoelectrochemical system for hydrogen production under simulated 1 sun illumination. The facile preparation of this Co-S film, along with its low overpotential, high activity, and long-term aqueous stability, offer promising features for potential use in solar energy applications. PMID:24219808

Sun, Yujie; Liu, Chong; Grauer, David C; Yano, Junko; Long, Jeffrey R; Yang, Peidong; Chang, Christopher J

2013-11-27

330

Hydrogen sulfide ameliorates lead-induced morphological, photosynthetic, oxidative damages and biochemical changes in cotton.  

PubMed

Poisonous lead (Pb), among heavy metals, is a potential pollutant that readily accumulates in soils and thus adversely affects physiological processes in plants. We have evaluated how exogenous H2S affects cotton plant physiological attributes and Pb uptake under Pb stress thereby understanding the role of H2S in physiological processes in plants. Two concentrations (0 and 200 ?M) of H2S donor sodium hydrosulfide (NaHS) were experimented on cotton plants under Pb stress (0, 50, and 100 ?M). Results have shown that Pb stress decreased plant growth, chlorophyll contents, SPAD value, photosynthesis, antioxidant activity. On the other hand, Pb stress increased the level of malondialdehyde (MDA), electrolyte leakage (EL), and production of H2O2 and uptake of Pb contents in all three parts of plant, viz. root, stem, and leaf. Application of H2S slightly increased plant growth, chlorophyll contents, SPAD value, photosynthesis, and antioxidant activity as compared to control. Hydrogen sulfide supply alleviated the toxic effects of lead on plant growth, chlorophyll contents, SPAD value, photosynthesis, and antioxidant activity in cotton plants. Hydrogen sulfide also reduced MDA, EL, and production of H2O2 and endogenous Pb levels in the three mentioned plant parts. On the basis of our results, we conclude that H2S has promotive effects which could improve plant survival under Pb stress. PMID:23852465

Bharwana, Saima Aslam; Ali, Shafaqat; Farooq, Muhammad Ahsan; Ali, Basharat; Iqbal, Naeem; Abbas, Farhat; Ahmad, Muhammad Sajid Aqeel

2014-01-01

331

Reduction of ferrylmyoglobin by hydrogen sulfide. Kinetics in relation to meat greening.  

PubMed

The hypervalent meat pigment ferrylmyoglobin, MbFe(IV)?O, characteristic for oxidatively stressed meat and known to initiate protein cross-linking, was found to be reduced by hydrogen sulfide to yield sulfmyoglobin. Horse heart myoglobin, void of cysteine, was used to avoid possible interference from protein thiols. For aqueous solution, the reactions were found to be second-order, and an apparent acid catalysis could be quantitatively accounted for in terms of a fast reaction between protonated ferrylmyoglobin, MbFe(IV)?O,H(+), and hydrogen sulfide, H2S (k2 = (2.5 ± 0.1) × 10(6) L mol(-1) s(-1) for 25.0 °C, ionic strengh 0.067, dominating for pH < 4), and a slow reaction between MbFe(IV)?O and HS(-) (k2 = (1.0 ± 0.7) × 10(4) L mol(-1) s(-1) for 25.0 °C, ionic strengh 0.067, dominating for pH > 7). For meat pH, a reaction via the transition state {MbFe(IV)?O···H···HS}([symbol: see text]) contributed significantly, and this reaction appeared almost independent of temperature with an apparent energy of activation of 2.1 ± 0.7 kJ mol(-1) at pH 7.4, as a result of compensation among activation energies and temperature influence on pKa values explaining low temperature greening of meat. PMID:23425699

Libardi, Silvia H; Pindstrup, Helene; Cardoso, Daniel R; Skibsted, Leif H

2013-03-20

332

Carbon dioxide and hydrogen sulfide associations with regional bacterial diversity patterns in microbially induced concrete corrosion.  

PubMed

The microbial communities associated with deteriorating concrete corrosion fronts were characterized in 35 samples taken from wastewater collection and treatment systems in ten utilities. Bacterial communities were described using Illumina MiSeq sequencing of the V1V2 region of the small subunit ribosomal ribonucleic acid (SSU-rRNA) gene recovered from fresh corrosion products. Headspace gas concentrations (hydrogen sulfide, carbon dioxide, and methane), pore water pH, moisture content, and select mineralogy were tested for correlation to community outcomes and corrosion extent using pairwise linear regressions and canonical correspondence analysis. Corroding concrete was most commonly characterized by moisture contents greater than 10%, pore water pH below one, and limited richness (<10 taxa). Bacterial community composition was not correlated to geographic location when considered independently from other environmental factors. Corrosion was most severe in sites with high levels of hydrogen sulfide (>100 ppm) and carbon dioxide (>1%) gases, conditions which also were associated with low diversity biofilms dominated by members of the acidophilic sulfur-oxidizer genus Acidithiobacillus. PMID:24842376

Ling, Alison L; Robertson, Charles E; Harris, J Kirk; Frank, Daniel N; Kotter, Cassandra V; Stevens, Mark J; Pace, Norman R; Hernandez, Mark T

2014-07-01

333

Solubility of hydrogen sulfide in water + monoethanolamine + 2-amino-2-methyl-1-propanol  

SciTech Connect

Alkanolamine aqueous solutions are widely used in gas treating processes to remove acid gases, such as CO[sub 2] and H[sub 2]S, from natural, refinery, and synthesis gas streams. The solubilities of hydrogen sulfide in water (1) + monoethanolamine (2) + 2-amino-2-methyl-1-propanol (3) have been measured at 40, 60, 80, and 100 C and at partial pressures of hydrogen sulfide ranging from 1.0 to 180 kPa. The ternary mixtures studied were [omega][sub 2] = 0, [omega][sub 3] = 0.3; [omega][sub 2] = 0.06, [omega][sub 3] = 0.24; [omega][sub 2] = 0.12, [omega][sub 3] = 0.18; [omega][sub 2] = 0.18, [omega][sub 3] = 0.12; and [omega][sub 2] = 0.24, [omega][sub 3] = 0.06 where [omega] is the mass fraction. The model of Kent and Eisenberg has been extended to represent the solubility of H[sub 2]S in the ternary mixtures. The model reasonably reproduces the equilibrium partial pressure of H[sub 2]S above the ternary mixtures, not only over a temperature range from 40 to 100 C, but also at various compositions of the components in the ternary mixture.

Li, M.H.; Chang, B.C. (Chung Yuan Christian Univ., Chung Li (Taiwan, Province of China). Dept. of Chemical Engineering)

1994-04-01

334

Equilibrium hydrate formation conditions for hydrogen sulfide, carbon dioxide, and ethane in aqueous solutions of ethylene glycol and sodium chloride  

SciTech Connect

Natural gas components such as hydrogen sulfide, carbon dioxide, and ethane form gas hydrates of structure I under suitable temperature and pressure conditions. Information on such conditions is vital to the oil and gas industry in order to design and operate processing equipment and pipelines so that hydrate formation is avoided. Incipient equilibrium hydrate formation conditions for hydrogen sulfide, carbon dioxide, and ethane in aqueous solutions of ethylene glycol and sodium chloride were experimentally obtained in the temperature range 264--290 K and the pressure range 0.23--3.18 MPa. A variable-volume sapphire cell was used for the measurements.

Majumdar, A.; Mahmoodaghdam, E.; Bishnoi, P.R.

2000-02-01

335

A theoretical analysis of non-chemical separation of hydrogen sulfide from methane by nano-porous membranes using capillary condensation  

Microsoft Academic Search

The potential of a nano-porous membrane to perform non-chemical separation of a gas mixture has been explored theoretically. Separation of hydrogen sulfide from its mixture with methane by capillary condensation has been selected as the model case. Because of its much lower condensation pressure compared to methane, hydrogen sulfide preferentially condenses in the fine pores and get transported by Poiseuille

Farooq Ahmad; H. Mukhtar; Z. Man; Binay. K. Dutta

2008-01-01

336

Hydrogen sulfide removal from coal gas by the metal-ferrite sorbents made from the heavy metal wastewater sludge.  

PubMed

The metal-ferrite (chromium-ferrite and zinc-ferrite) sorbents made from the heavy metal wastewater sludge have been developed for the hydrogen sulfide removal from coal gas. The high temperature absorption of hydrogen sulfide from coal gas with the metal-ferrite sorbent in a fixed bed reactor was conducted in this study. The metal-ferrite powders were the products of the ferrite process for the heavy metal wastewater treatment. The porosity analysis results show that the number of micropores of the sorbents after sulfidation and regeneration process decreases and the average pore size increases due to the acute endothermic and exothermic reactions during the sulfidation-regeneration process. The FeS, ZnS, and MnS peaks are observed on the sulfided sorbents, and the chromium extraction of the CFR6 can fulfill the emission standard of Taiwan EPA. The suitable sulfidation temperature range for chromium-ferrite sorbent is at 500-600 degrees C. In addition, effects of various concentrations of H2 and CO were also conducted in the present work at different temperatures. By increasing the H2 concentration, the sulfur sorption capacity of the sorbent decreases and an adverse result is observed in the case of increasing CO concentration. This can be explained via water-shift reaction. PMID:18440697

Tseng, Ting Ke; Chang, Han Ching; Chu, Hsin; Chen, Hung Ta

2008-12-30

337

The influence of hydrogen sulfide-to-hydrogen partial pressure ratio on the sulfidization of Pd and 70 mol% Pd–Cu membranes  

SciTech Connect

The influence of H2S-to-H2 partial pressure ratio on the sulfidization of Pd and 70 mol% Pd–Cu membrane alloys was studied using various H2Scontaining gas mixtures. The Pd membranes exposed to various H2S mixtures were in very good agreement with the thermodynamic calculations used in this study, resisting sulfidization when exposed to H2S-to-H2 ratios below the equilibrium value predicted for Pd4S formation, and experiencing sulfidization when exposed to ratios above the equilibrium values. The 70 mol% Pd–Cu membranes, however, exhibited deviations from the predicted values, resisting sulfidization at some conditions close to the equilibrium values at which sulfidization was expected, and experiencing sulfidization at some conditions at which resistance was expected. This phenomenon was attributed to deviations of the Pd–Cu alloy from ideality, probably due to Cu segregation at the membrane surface.

Iyoha, O.; Enick, R.M.; Killmeyer, R.P.; Morreale, B.

2007-11-15

338

The influence of hydrogen sulfide-to-hydrogen partial pressure ratio on the sulfidization of Pd and 70 mol% Pd-Cu membranes  

SciTech Connect

The influence of H2S-to-H2 partial pressure ratio on the sulfidization of Pd and 70 mol% Pd–Cu membrane alloys was studied using various H2S-containing gas mixtures. The Pd membranes exposed to various H2S mixtures were in very good agreement with the thermodynamic calculations used in this study, resisting sulfidization when exposed to H2S-to-H2 ratios below the equilibrium value predicted for Pd4S formation, and experiencing sulfidization when exposed to ratios above the equilibrium values. The 70 mol% Pd–Cu membranes, however, exhibited deviations from the predicted values, resisting sulfidization at some conditions close to the equilibrium values at which sulfidization was expected, and experiencing sulfidization at some conditions at which resistance was expected. This phenomenon was attributed to deviations of the Pd–Cu alloy from ideality, probably due to Cu segregation at the membrane surface.

Iyoha, O.; Enick, R.M.; Killmeyer, R.P.; Morreale, B.D.

2007-11-15

339

Protection of steel from hydrogenation in a hydrogen-sulfide medium by means of inhibitors  

Microsoft Academic Search

Hydrogenation of steel was studied by an electrochemical method [3, 4], while hydrogen embrittlement was studied by twisting wire specimens with an axial tensile stress of 0.4 o- b. The tests were carried out on specimens of steel St. 3 in the as-supplied condition. For the electrochemical investigation of hydrogenation we used specimens inthe form of disks 20 ~= 0.1

A. K. Mindyuk; E. I. Svist

1975-01-01

340

Organic sulfur compounds resulting from the interaction of iron sulfide, hydrogen sulfide and carbon dioxide in an anaerobic aqueous environment.  

PubMed

The reaction of iron sulfide (FeS) with H2S in water, in presence of CO2 under anaerobic conditions was found to yield H2 and a variety of organic sulfur compounds, mainly thiols and small amounts of CS2 and dimethyldisulfide. The same compounds were produced when H2S was replaced by HCl, in the H2S-generating system FeS/HCl/CO2. The identification of the products was confirmed by GC-MS analyses and the incorporation of H2 in the organic sulfur compounds was demonstrated by experiments in which all hydrogen compounds were replaced by deuterium compounds. Generation of H2 and the synthesis of thiols were both dependent upon the relative abundance of FeS and HCl or H2S, i.e. the FeS/HCl- or FeS/H2S-proportions. Whether thiols or CS2 were formed as the main products depended also on the FeS/HCl-ratio: All conditions which create a H2 deficiency were found to initiate a proportional increase in the amount of CS2. The quantities of H2 and thiols generated depended on temperature: the production of H2 was significantly accelerated from 50 degrees C onward and thiol synthesis above 75 degrees C. The yield of thiols increased with the amount of FeS and HCl (H2S), given a certain FeS/HCl-ratio and a surplus of CO2. A deficiency of CO2 results in lower thiol synthesis. The end product, pyrite (FeS2), was found to appear as a silvery granular layer floating on the aqueous surface. The identity of the thiols was confirmed by mass spectrometry, and the reduction of CO2 demonstrated by the determination of deuterium incorporation with DCl and D2O. The described reactions can principally proceed under the conditions comparable to those obtaining around submarine hydrothermal vents, or the global situation about 4 billion years ago, before the dawn of life, and could replace the need for a reducing atmosphere on the primitive earth. PMID:11536750

Heinen, W; Lauwers, A M

1996-04-01

341

Organic sulfur compounds resulting from the interaction of iron sulfide, hydrogen sulfide and carbon dioxide in an anaerobic aqueous environment  

NASA Astrophysics Data System (ADS)

The reaction of iron sulfide (FeS) with H2S in water, in presence of CO2 under anaerobic conditions was found to yield H2 and a variety of organic sulfur compounds, mainly thiols and small amounts of CS2 and dimethyldisulfide. The same compounds were produced when H2S was replaced by HCl, in the H2S-generating system FeS/HCl/CO2. The identification of the products was confirmed by GC-MS analyses and the incorporation of H2 in the organic sulfur compounds was demonstrated by experiments in which all hydrogen compounds were replaced by deuterium compounds. Generation of H2 and the synthesis of thiols were both dependent upon the relative abundance of FeS and HCl or H2S, i.e. the FeS/HCl- or FeS/H2S-proportions. Whether thiols or CS2 were formed as the main products depended also on the FeS/HCl-ratio: All conditions which create a H2 deficiency were found to initiate a proportional increase in the amount of CS2. The quantities of H2 and thiols generated depended on temperature: the production of H2 was significantly accelerated from 50°C onward and thiol synthesis above 75°C. The yield of thiols increased with the amount of FeS and HCl (H2S), given a certain FeS/HCl-ratio and a surplus of CO2. A deficiency of CO2 results in lower thiol systhesis. The end product, pyrite (FeS2), was found to appear as a silvery granular layer floating on the aqueous surface. The identity of the thiols was confirmed by mass spectrometry, and the reduction of CO2 demonstrated by the determination of deuterium incorporation with DCl and D2O. The described reactions can principally proceed under the conditions comparable to those obtaining around submarine hydrothermal vents, or the global situation about 4 billion years ago, before the dawn of life, and could replace the need for a reducing atmosphere on the primitive earth.

Heinen, Wolfgang; Lauwers, Anne Marie

1996-04-01

342

Hydrogen sulfide removal from sediment and water in box culverts/storm drains by iron-based granules.  

PubMed

A renewable granular iron-based technology for hydrogen sulfide removal from sediment and water in box culverts and storm drains is discussed. Iron granules, including granular ferric hydroxide (GFH), granular ferric oxide (GFO) and rusted waste iron crusts (RWIC) embedded in the sediment phase removed aqueous hydrogen sulfide formed from sedimentary biological sulfate reduction. The exhausted iron granules were exposed to dissolved oxygen and this regeneration process recovered the sulfide removal capacities of the granules. The recovery is likely attributable to the oxidation of the ferrous iron precipitates film and the formation of new reactive ferric iron surface sites on the iron granules and sand particles. GFH and RWIC showed larger sulfide removal capacities in the sediment phase than GFO, likely due to the less ordered crystal structures on their surfaces. This study demonstrates that the iron granules are able to remove hydrogen sulfide from sediment and water in box culverts and storm drains and they have the potential to be regenerated and reused by contacting with dissolved oxygen. PMID:24355850

Sun, J L; Shang, C; Kikkert, G A

2013-01-01

343

Partitioning of K, U, and Th between sulfide and silicate liquids - Implications for radioactive heating of planetary cores  

NASA Technical Reports Server (NTRS)

Experimental partitioning studies are reported of K, U, and Th between silicate and FeFeS liquids designed to test the proposal that actinide partitioning into sulfide liquids is more important then K partitioning in the radioactive heating of planetary cores. For a basaltic liquid at 1450 C and 1.5 GPa, U partitioning into FeFeS liquids is five times greater than K partitioning. A typical value for the liquid partition coefficient for U from a granitic silicate liquid at one atmosphere at 1150 C and low fO2 is about 0.02; the coefficient for Th is similar. At low fO2 and higher temperature, experiments with basaltic liquids produce strong Ca and U partitioning into the sulfide liquid with U coefficient greater than one. The Th coefficient is less strongly affected.

Murrell, M. T.; Burnett, D. S.

1986-01-01

344

Electrically Conducting Polymer-Copper Sulphide Composite Films, Preparation by Treatment of Polymer-Copper (2) Acetate Composites with Hydrogen Sulfide  

NASA Technical Reports Server (NTRS)

Polymer copper sulfide composite films were prepared by treatment of polymer poly(vinyl chloride), poly(acrylonitrile), copolymer of vinyl chloride and vinyl acetate (90:10), and ABS resin copper (2) acetate composites with hydrogen sulfide. The films showed electrical conductivity higher than 0.015 S/cm when they contained more than 20 wt percent of copper sulfide. A poly(acrylonitrile)-copper sulfide composite film containing 40 to 50 wt percent of copper sulfide showed electrical conductivity of 10 to 150.0 S/cm and had relatively high mechanical strength to be used in practical purposes.

Yamamoto, Takakazu; Kamigaki, Takahira; Kubota, Etsuo

1988-01-01

345

Demonstration of a pulsing liquid hydrogen/liquid oxygen thruster  

NASA Technical Reports Server (NTRS)

Successful operation of a pulsing liquid hydrogen/liquid oxygen attitude control propulsion system thruster (1250 lb sub f) at cryogenic inlet conditions while maintaining high specific impulse and low impulse bit capability was demonstrated. Significant technical advances and departures from conventional injector design practices were necessary in order to achieve an operable thruster. These advancements were achieved through extensive analyses of heat transfer and injector manifold priming that established the baseline feasibility for an actual hardware design. The primary subject of this paper is the result of experimental evaluation of the 45 R hydrogen inlet temperature injector concept. The test matrix consisted of 66 hot firing tests in a heat sink thrust chamber.

Herr, P. N.; Choenman, L.

1973-01-01

346

Clean-up of low-concentration ventilation discharge from viscose manufacturing plants from carbon disulfide and hydrogen sulfide  

Microsoft Academic Search

Three basic trends are described in cleaning up low-concentration discharges from carbon disulfide in order to protect the atmosphere from industrial contaminants: using activated carbon fabrics, alkalized activated carbons, or absorptive solution containing chemosorbents or catalysts. In the case where the third method is used, hydrogen sulfide is removed by use of the same absorptive solution which from carbon disulfide

I. G. Shimko; S. K. Chinennaya; V. P. Katushkin; V. S. Minster; L. I. Pechalin; L. A. Rybakov; R. I. Zakirova

1984-01-01

347

Simultaneous solubility of ammonia and hydrogen sulfide in water at temperatures from 313 K to 393 K  

Microsoft Academic Search

The simultaneous solubility of ammonia and hydrogen sulfide in water was measured at temperatures from 313 to 393 K and total pressures up to 0.7 MPa. An adapted Pitzer model is used to correlate the new data. Experimental results are reported and compared to the limited literature data and the correlation.

B. Rumpf; Á. Pérez-Salado Kamps; R. Sing; G. Maurer

1999-01-01

348

Solubility of hydrogen sulfide, sulfur dioxide, carbon dioxide, propane, and n-butane in poly(glycol ethers)  

Microsoft Academic Search

Data on the solubility of acid and hydrocarbon gases for poly(glycol ethers) are necessary for the development of the University of California, Berkeley, Sulfur Removal Process. An automated gas solubility measurement system was used to collect data on the solubility of hydrogen sulfide, carbon dioxide, propane, and n-butane in a variety of these solvents. The partial pressure of solute gas

Steven F. Sciamanna; Scott Lynn

1988-01-01

349

Liquid Metallic Hydrogen: Building Block of a Liquid Sun  

NASA Astrophysics Data System (ADS)

The establishment by Andrews of critical temperatures (T. Andrews, Phil. Trans. 1869, v. 159, 575-590) soon became one of the great pillars in support of the gaseous models of the Sun. Gases above these temperatures simply could not be liquefied. Given that interior of the Sun was already hypothesized in the 19th century to be at temperatures well exceeding those achievable on Earth in ordinary furnaces, it became inconceivable to think of the solar interior as anything but gaseous. Hence, the models advanced by Secchi, Faye, Stoney, Lane, and Young, could easily gain acceptance. However, modern science is beginning to demonstrate that hydrogen (which under ordinary conditions has a critical point at ˜33 K) can become pressure ionized such that its electrons enter metallic conductions bands, given sufficiently elevated pressures, as the band gap is reduced from 15 eV to ˜0.3 eV. Liquid metallic hydrogen will possess a new critical temperature well above that of ordinary hydrogen. Already, experiments suggests that it can exist at temperatures of thousands of Kelvin and millions of atmospheres (S. T. Weir et al., Phys. Rev. Let. 1996, 76, 1860). The formation of liquid metallic hydrogen brings with it a new candidate for the interior of the Sun and the stars. Its existence shatters the great pillar of the gaseous models of the Sun which the critical point of ordinary gases had erected.

Robitaille, Pierre-Marie

2011-04-01

350

Electrochemical behavior of A516 carbon steel in solutions containing hydrogen sulfide  

SciTech Connect

The electrochemical behavior of A516 grade 70 (UNS K02700) carbon steel with a ferrite-pearlite structure in acidic chloride (Cl{sup {minus}}) solutions containing hydrogen sulfide at 25 C was investigated by electrochemical impedance spectroscopy (EIS). Results showed the impedance of A516 steel increased in an acidic Cl{sup {minus}} solution with H{sub 2}S (compared to a solution without H{sub 2}S) at the open-circuit potential (OCP). The corrosion process for A516 steel in the H{sub 2}S-containing solution was in two stages. Polarization resistance initially increased with time for immersion up to {approximately} 10 h but then decreased gradually. In the early stage, the impedance was characterized by one large semicircle in the Nyquist plot that increased with time for immersion up to 3 h. In the later stage, precipitation of a sulfide film modified the surface properties and led to variation in EIS data through a capacitive effect in the low-frequency region.

Huang, H.H.; Tsai, W.T.; Lee, J.T. [National Cheng Kung Univ., Tainan (Taiwan, Province of China). Dept. of Materials Science and Engineering

1996-09-01

351

Study of Hydrogen Recovery Systems for Gas Vented While Refueling Liquid-Hydrogen Fueled Aircraft  

NASA Technical Reports Server (NTRS)

Methods of capturing and reliquefying the cold hydrogen vapor produced during the fueling of aircraft designed to utilize liquid hydrogen fuel were investigated. An assessment of the most practical, economic, and energy efficient of the hydrogen recovery methods is provided.

Baker, C. R.

1979-01-01

352

A highly selective fluorescent probe for quantitative detection of hydrogen sulfide.  

PubMed

We designed and synthesized a highly selective and sensitive fluorescent probe for hydrogen sulfide (H2S) based on the one step nucleophilic addition reaction between H2S and electron-poor C=C double bond. Our proposed probe displayed high selectivity for H2S over other analytes including cysteine (Cys) and glutathione (GSH), which might be because the steric hindrance of H2S is less than other thiols. Additionally, a linear relationship between fluorescence intensity and the concentrations of Na2S (0-450 ?M) was obtained in an aqueous buffer solution (pH 7.4, 20 mM PBS). Particularly, we found that the adoption of the acetyl benzimidazole derivative as a recognition receptor to distinguish H2S from other thiols and analytes provides a promising methodology for the design of fluorescent probes for the determination of H2S. PMID:24334983

Ding, Jing; Ge, Yanqing; Zhu, Baocun

2013-01-01

353

NBD-based colorimetric and fluorescent turn-on probes for hydrogen sulfide.  

PubMed

Hydrogen sulfide (H2S) is an important endogenous signalling molecule and also an important environmental target for detection. New reaction-based colorimetric and fluorescent turn-on probes based on selective thiolyling of NBD (7-nitro-1,2,3-benzoxadiazole) ether were explored for sensing of H2S in aqueous buffer. The syntheses of both probes are simple and quite straightforward. The probes are highly sensitive and selective toward H2S over other biologically relevant species. Probe 1 can be used to directly visualize H2S by the naked eye and shows more than 1000-fold fluorescence increase upon reaction with H2S. Probe 2 is a near-infrared fluorescent sensor for H2S at physiological pH. PMID:24276473

Wei, Chao; Zhu, Qing; Liu, Weiwei; Chen, Wenbin; Xi, Zhen; Yi, Long

2014-01-21

354

Hydrogen Sulfide as an Endogenous Modulator in Mitochondria and Mitochondria Dysfunction  

PubMed Central

Hydrogen sulfide (H2S) has historically been considered to be a toxic gas, an environmental and occupational hazard. However, with the discovery of its presence and enzymatic production through precursors of L-cysteine and homocysteine in mammalian tissues, H2S has recently received much interest as a physiological signaling molecule. H2S is a gaseous messenger molecule that has been implicated in various physiological and pathological processes in mammals, including vascular relaxation, angiogenesis, and the function of ion channels, ischemia/reperfusion (I/R), and heart injury. H2S is an endogenous neuromodulator and present studies show that physiological concentrations of H2S enhance NMDA receptor-mediated responses and aid in the induction of hippocampal long-term potentiation. Moreover, in the field of neuronal protection, physiological concentrations of H2S in mitochondria have many favorable effects on cytoprotection.

Guo, Wei; Kan, Jun-tao; Cheng, Ze-yu; Chen, Jie-fang; Shen, Ya-qi; Xu, Jie; Wu, Dan; Zhu, Yi-zhun

2012-01-01

355

Experience with service of fittings of 20GML steel in hydrogen sulfide-bearing media  

SciTech Connect

The fabrication and testing of pipe and valve fittings 20GML steel for use in gas condensate field production equipment are described. The bodies of the fittings were cast from 20GML steel and the internal components were produced using 10Kh17N13M3T steel. Hardfacing and heat treatment regimes are described and the resulting mechanical and anticorrosion properties are given. The fittings were designed to minimize or eliminate corrosion cracking in hydrogen sulfide-containing reservoir fluids. Tests included mechanical, leak, and dye penetrant and were performed over an eight-year period and demonstrated successful use of the valves in gas condensate deposits containing up to 6% H/sub 2/S.

Petrova, A.M.; Pagnueva, I.A.; Sergeeva, G.A.

1988-05-01

356

Hydrogen sulfide-releasing aspirin inhibits the growth of leukemic Jurkat cells and modulates ?-catenin expression.  

PubMed

Hydrogen sulfide-releasing aspirin (HS-ASA) is a novel compound with potential against cancer. It inhibited the growth of Jurkat T-leukemia cells with an IC?? of 1.9 ± 0.2 ?M whereas that of ASA was >5000 ?M. It dose-dependently inhibited proliferation and induced apoptosis in these cells, causing a G?/G? cell cycle arrest. HS-ASA down-regulated ?-catenin protein levels and reduced mRNA and protein expression of ?-catenin/TCF downstream target genes cyclinD1 and c-myc. Aspirin up to 5 mM had no effect on ?-catenin expression. HS-ASA also increased caspase-3 protein levels and dose-dependently increased its activity. These effects were substantially blocked by z-VAD-fmk, a pan-caspase inhibitor. PMID:23896061

Chattopadhyay, Mitali; Nath, Niharika; Kodela, Ravinder; Sobocki, Tomasz; Metkar, Shalaka; Gan, Zong Yuan; Kashfi, Khosrow

2013-10-01

357

Adsorption of hydrogen sulfide onto activated carbon fibers: effect of pore structure and surface chemistry.  

PubMed

To understand the nature of H2S adsorption onto carbon surfaces under dry and anoxic conditions, the effects of carbon pore structure and surface chemistry were studied using activated carbon fibers (ACFs) with different pore structures and surface areas. Surface pretreatments, including oxidation and heattreatment, were conducted before adsorption/desorption tests in a fixed-bed reactor. Raw ACFs with higher surface area showed greater adsorption and retention of sulfur, and heat treatment further enhanced adsorption and retention of sulfur. The retained amount of hydrogen sulfide correlated well with the amount of basic functional groups on the carbon surface, while the desorbed amount reflected the effect of pore structure. Temperature-programmed desorption (TPD) and thermal gravimetric analysis (TGA) showed that the retained sulfurous compounds were strongly bonded to the carbon surface. In addition, surface chemistry of the sorbent might determine the predominant form of adsorbate on the surface. PMID:16475362

Feng, Wenguo; Kwon, Seokjoon; Borguet, Eric; Vidic, Radisav

2005-12-15

358

A Hypothesis: Hydrogen Sulfide Might Be Neuroprotective against Subarachnoid Hemorrhage Induced Brain Injury  

PubMed Central

Gases such as nitric oxide (NO) and carbon monoxide (CO) play important roles both in normal physiology and in disease. Recent studies have shown that hydrogen sulfide (H2S) protects neurons against oxidative stress and ischemia-reperfusion injury and attenuates lipopolysaccharides (LPS) induced neuroinflammation in microglia, exhibiting anti-inflammatory and antiapoptotic activities. The gas H2S is emerging as a novel regulator of important physiologic functions such as arterial diameter, blood flow, and leukocyte adhesion. It has been known that multiple factors, including oxidative stress, free radicals, and neuronal nitric oxide synthesis as well as abnormal inflammatory responses, are involved in the mechanism underlying the brain injury after subarachnoid hemorrhage (SAH). Based on the multiple physiologic functions of H2S, we speculate that it might be a promising, effective, and specific therapy for brain injury after SAH.

Yu, Yong-Peng; Chi, Xiang-Lin; Liu, Li-Jun

2014-01-01

359

Kinetics of homolytic substitutions by hydrogen atoms at thiols and sulfides.  

PubMed

Thermodynamic and kinetic data in the temperature range 300-1500 K are calculated for 94 homolytic substitution reactions by a hydrogen atom at thiols and sulfides with the CBS-QB3//BMK/6-311G(2d,d,p) method. The studied reactions were found to proceed according to a one-step mechanism. A group additivity (GA) method is presented to model the Arrhenius parameters of this reaction family. The required GA values were derived from data obtained for a set containing 58 reactions. By using the developed GA scheme, rate coefficients at 300 K for 26 substitution reactions by the hydrogen atom are reproduced within a factor of 2.2. Mean absolute deviations on the activation energy and pre-exponential factor are limited to 1.1 kJ mol(-1) and 0.19, respectively. Rate coefficients for the reverse reactions, that is, substitution reactions by C- and S-centered radicals with expulsion of a hydrogen atom, are reproduced within a factor of 6 by using thermodynamic consistency. At 1000 K, group additive and calculated rate coefficients for the forward and reverse reactions agree within a factor of 1.8 and 4, respectively. Experimental rate coefficients in the temperature range 300-400 K are reproduced within a factor of 5. Discrepancies between calculated and experimental data are discussed. PMID:23589441

Vandeputte, Aäron G; Reyniers, Marie-Françoise; Marin, Guy B

2013-06-01

360

Inhaled hydrogen sulfide protects against lipopolysaccharide-induced acute lung injury in mice  

PubMed Central

Background Local pulmonary and systemic infections can lead to acute lung injury (ALI). The resulting lung damage can evoke lung failure and multiple organ dysfunction associated with increased mortality. Hydrogen sulfide (H2S) appears to represent a new therapeutic approach to ALI. The gas has been shown to mediate potent anti-inflammatory and organ protective effects in vivo. This study was designed to define its potentially protective role in sepsis-induced lung injury. Methods C57BL/6 N mice received lipopolysaccharide (LPS) intranasally in the absence or presence of 80 parts per million H2S. After 6 h, acute lung injury was determined by comparative histology. Bronchoalveolar lavage (BAL) fluid was analyzed for total protein content and differential cell counting. BAL and serum were further analyzed for interleukin-1?, macrophage inflammatory protein-2, and/or myeloperoxidase glycoprotein levels by enzyme-linked immunosorbent assays. Differences between groups were analyzed by one way analysis of variance. Results Histological analysis revealed that LPS instillation led to increased alveolar wall thickening, cellular infiltration, and to an elevated ALI score. In the presence of H2S these changes were not observed despite LPS treatment. Moreover, neutrophil influx, and pro-inflammatory cytokine release were enhanced in BAL fluid of LPS-treated mice, but comparable to control levels in H2S treated mice. In addition, myeloperoxidase levels were increased in serum after LPS challenge and this was prevented by H2S inhalation. Conclusion Inhalation of hydrogen sulfide protects against LPS-induced acute lung injury by attenuating pro-inflammatory responses.

2012-01-01

361

Contribution of cysteine aminotransferase and mercaptopyruvate sulfurtransferase to hydrogen sulfide production in peripheral neurons.  

PubMed

Hydrogen sulfide (H2 S) is a gaseous neuromodulator produced from L-cysteine. H2 S is generated by three distinct enzymatic pathways mediated by cystathionine ?-lyase (CSE), cystathionine ?-synthase (CBS), and mercaptopyruvate sulfurtransferase (MPST) coupled with cysteine aminotransferase (CAT). This study investigated the relative contributions of these three pathways to H2 S production in PC12 cells (rat pheochromocytoma-derived cells) and the rat dorsal root ganglion. CBS, CAT, and MPST, but not CSE, were expressed in the cells and tissues, and appreciable amounts of H2 S were produced from L-cysteine in the presence of ?-ketoglutarate, together with dithiothreitol. The production of H2 S was inhibited by a CAT inhibitor (aminooxyacetic acid), competitive CAT substrates (L-aspartate and oxaloacetate), and RNA interference (RNAi) against MPST. Immunocytochemistry revealed a mitochondrial localization of MPST in PC12 cells and dorsal root ganglion neurons, and the amount of H2 S produced by CAT/MPST at pH 8.0, a physiological mitochondrial matrix pH, was comparable to that produced by CSE and CBS in the liver and the brain, respectively. Furthermore, H2 S production was markedly increased by alkalization. These results indicate that CAT and MPST are primarily responsible for H2 S production in peripheral neurons, and that the regulation of mitochondrial metabolism may influence neuronal H2 S generation. In the peripheral nervous system, hydrogen sulfide (H2 S) has been implicated in neurogenic pain or hyperalgesia. This study provides evidence that H2 S is synthesized in peripheral neurons through two mitochondrial enzymes, cysteine aminotransferase (CAT) and mercaptopyruvate sulfurtransferase (MPST). We propose that mitochondrial metabolism plays key roles in the physiology and pathophysiology of the peripheral nervous system via regulation of neuronal H2 S production. PMID:24611772

Miyamoto, Ryo; Otsuguro, Ken-Ichi; Yamaguchi, Soichiro; Ito, Shigeo

2014-07-01

362

Hydrogen sulfide mitigates matrix metalloproteinase-9 activity and neurovascular permeability in hyperhomocysteinemic mice*  

PubMed Central

An elevated level of homocysteine (Hcy), known as hyperhomocysteinmia (HHcy), was associated with neurovascular diseases. At physiological levels, hydrogen sulfide (H2S) protected the neurovascular system. Because Hcy was also a precursor of hydrogen sulfide (H2S), we sought to test whether the H2S protected the brain during HHcy. Cystathionine-?-synthase heterozygous (CBS+/?) and wild type (WT) mice were supplemented with or without NaHS (30 µM/L, H2S donor) in drinking water. Blood flow and cerebral microvascular permeability in pial vessels were measured by intravital microscopy in WT, WT+NaHS, CBS?/+ and CBS?/+ + NaHS treated mice. The brain tissues were analyzed for matrix metalloproteinase (MMP) and tissue inhibitor of metalloproteinase (TIMP) by Western blot and RT-PCR. The mRNA levels of CBS and cystathionine gamma lyase (CSE, enzyme responsible for conversion of Hcy to H2S) genes were measured by RT-PCR. The results showed a significant increase in MMP-2, MMP-9, TIMP-3 protein and mRNA in CBS (?/+) mice, while H2S treatment mitigated this increase. Interstitial localization of MMPs was also apparent through Immunohistochemistry. A decrease in protein and mRNA expression of TIMP-4 was observed in CBS (?/+) mice. Microscopy data revealed increase in permeability in CBS (?/+) mice. These effects were ameliorated by H2S and suggested that physiological levels of H2S supplementation may have therapeutic potential against HHcy-induced microvascular permeability, in part, by normalizing the MMP/TIMP ratio in the brain.

Tyagi, Neetu; Givvimani, Srikanth; Qipshidze, Natia; Kundu, Soumi; Kapoor, Shray; Vacek, Jonathan C.; Tyagi, Suresh C.

2010-01-01

363

Protective effect of hydrogen sulfide on gentamicin-induced renal injury.  

PubMed

Abstract Objective: We evaluated the potential protective effect of hydrogen sulfide (H2S) against GEN-induced nephrotoxicity in rats. Materials and methods: Twenty-four rats were randomly divided into four groups, each consisting of six animals as follows: (1) the rats were control, (2) intraperitoneally injected with GEN 14 consecutive days (100?mg/kg/day), (3) treated with GEN plus %0.9 saline intraperitoneally for 14 days and (4) treated with GEN plus sodium hydrogen sulfide (NaHS)-exogenous H2S donor (56?µmol/kg/day) for 14 days. After 15 days, rats were sacrificed and their kidneys were taken and blood analysis was performed. Twenty-four hours urine collections were obtained in standard metabolic cages a day before the rats were sacrificed. Tubular necrosis and interstitial fibrosis scoring were determined histopathologically in a part of kidneys; nitric oxide (NO), malondialdehyde (MDA) and reduced glutathione (GSH) levels were determined in the other part of kidneys. Statistical analyses were made by the chi-squared test and one-way analysis of variance. Results: Serum urea and creatinine levels were significantly higher in rats treated with GEN alone, than the rats in control and GEN?+?NaHS groups. The GSH levels in renal tissue of only GEN-treated rats were significantly lower than those in control group, and administration of NaHS to GEN-treated rats significantly increased the level of GSH. The group that was given GEN and NaHS had significantly lower MDA and NO levels in kidney cortex tissue than those that was given GEN alone. In rats treated with GEN?+?NaHS, despite the presence of mild tubular degeneration and tubular necrosis are less severe, and glomeruli maintained a better morphology when compared with GEN group. Discussion: We can say that H2S prevent kidney damage with antioxidant and anti-inflammatory effect. PMID:24679071

Otunctemur, Alper; Ozbek, Emin; Dursun, Murat; Sahin, Suleyman; Besiroglu, Huseyin; Ozsoy, Ozgur Doga; Cekmen, Mustafa; Somay, Adnan; Ozbay, Nurver

2014-07-01

364

Hydrogen sulfide impairs keratinocyte cell growth and adhesion inhibiting mitogen-activated protein kinase signaling.  

PubMed

The effects of exogenous hydrogen sulfide (H2S) on normal skin-derived immortalized human keratinocytes have been investigated in detail. We show in vitro that exogenous hydrogen sulfide reduces clonal growth, cell proliferation and cell adhesion of human keratinocytes. H(2)S, in fact, decreases the frequency of the putative keratinocyte stem cell subpopulation in culture, consequently affecting clonal growth, and impairs cell proliferation and adhesion of mature cells. As a mechanistic explanation of these effects, we show at the molecular level that (i) H2S reduces the Raf/MAPK kinase/ERK signaling pathway; (ii) the reduced adhesion of sulfur-treated cells is associated to the downregulation of the expression of beta4, alpha2 and alpha6 integrins that are necessary to promote cell adhesion as well as anti-apoptotic and proliferative signaling in normal keratinocytes. One specific interest of the effects of sulfurs on keratinocytes derives from the potential applications of the results, as sulfur is able to penetrate the skin and a sulfur-rich balneotherapy has been known for long to be effective in the treatment of psoriasis. Thus, the relevance of our findings to the pathophysiology of psoriasis was tested in vivo by treating psoriatic lesions with sulfurs at a concentration comparable to that most commonly found in sulfurous natural springs. In agreement with the in vitro observations, the immunohistochemical analysis of patient biopsies showed a specific downregulation of ERK activation levels, the key molecular event in the sulfur-induced effects on keratinocytes. PMID:19546851

Gobbi, Giuliana; Ricci, Francesca; Malinverno, Chiara; Carubbi, Cecilia; Pambianco, Maurizia; Panfilis, Giuseppe de; Vitale, Marco; Mirandola, Prisco

2009-09-01

365

Physical solubility of hydrogen sulfide and carbon dioxide in alkanolamine solutions  

SciTech Connect

The study was undertaken to develop a method that would make direct measurements of acid gases, hydrogen sulfide and carbon dioxide, physical solubilities in aqueous alkanolamine solutions possible. Hydrogen sulfide and carbon dioxide physical solubilities in 20, 35, and 50% by weight diethanolamine aqueous solutions were measured. The solubility measurements were made at acid gas partial pressure up to 1000 psia and temperatures of 80, 150, 240 F. The solubility of nitrous oxide in water and in protonated diethanolamine solution was also determined at 80 F. A method that allows for direct measurements of acid gases physical solubilities has been developed. The method eliminates amines reactivity with acid gases by protonating the amines prior to their contact with acid gases. CO{sub 2} physical solubility in aqueous DEA solutions occurs mainly in the water portion of the solution. Therefore, the physical solubility of CO{sub 2} in an aqueous amine solution must be corrected based on the fraction of water in the solution. However, H{sub 2}S physical solubility in aqueous DEA solutions is the same as H{sub 2}S solubility in water. At any acid gas partial pressure, the physical solubility of H{sub 2}S is higher than that of CO{sub 2} for the same solution concentration and for the same temperature. This is also true for their solubilities is pure water. The ratio of CO{sub 2} to H{sub 2}S physical solubility to N{sub 2}O solubility in aqueous DEA solutions is not the same as their ratio in pure water.

Abu-Arabi, M.K.

1988-01-01

366

Hydrogen sulfide oxidation is coupled to oxidative phosphorylation in mitochondria of Solemya reidi  

SciTech Connect

Solemya reidi, a gutless clam found in sulfide-rich habitats, contains within its gills bacterial symbionts thought to oxidize sulfur compounds and provide a reduced carbon food source to the clam. However, the initial step or steps in sulfide oxidation occur in the animal tissue, and mitochondria isolated from both gill and symbiont-free foot tissue of the clam coupled the oxidation of sulfide to oxidative phosphorylation (adenosine triphosphate (ATP) synthesis). The ability of Solemya reidi to exploit directly the energy in sulfide for ATP synthesis is unprecedented, and suggests that sulfide-habitat animals that lack bacterial symbionts may also use sulfide as an inorganic energy source.

Powell, M.A.; Somero, G.N.

1986-08-01

367

Experiments on microjets of undercooled liquid hydrogen  

NASA Astrophysics Data System (ADS)

Novel experiments on liquid microjets (filaments) of hydrogen and deuterium, carried out at the Laboratory of Molecular Fluid Dynamics of the IEM, are reported. These filaments, less than 10 microns in diameter, are an ideal medium to produce highly undercooled liquid samples and to investigate the homogeneous solidification process, free from wall effects. The filaments exit from cryogenic capillary nozzles into a vacuum chamber, to cool down very fast by surface evaporation. Finite size radius leads to a temperature gradient across the filament, determined by thermal conductivity, and, possibly, to a velocity gradient as well. The filaments are monitored by laser shadowgraphy, and analyzed by means of high performance Raman spectroscopy. Real-time measurements in the rotational and vibrational spectral regions reveal the structure and temperature along the filaments, allowing to track the crystal growth process. The high spatial resolution of Raman spectroscopy allows observing in situ the structural changes of the liquid microjets, with a time resolution of ~ 10 ns. The filaments of pure para-H2 can be cooled down to 9 K (65% of its melting point at 13.8 K), while staying liquid, before eventually solidifying into a metastable polymorph. Crystallization kinetics revealed a growth rate of 33 cm/s, much higher than expected for a thermally activated process. The time and spatial control attained in these experiments offers new opportunities for investigating the processes of nonequilibrium phase transformations in undercooled fluids, as well as the propagation of liquid jets into a rarefied gas media.

Fernández, José M.; Kühnel, Matthias; Tejeda, Guzmán; Kalinin, Anton; Grisenti, Robert E.; Montero, Salvador

2012-11-01

368

Theoretical analysis for the heterogeneous decomposition of hydrogen sulfide to hydrogen on an iron-metallic plate in a laminar stagnation-point flow  

NASA Astrophysics Data System (ADS)

In this work, we have theoretically analyzed the conversion process of hydrogen sulfide, H 2S, to atomic hydrogen, H 0, in a planar stagnation-point flow over an iron-metallic surface. We assume that a binary mixture of hydrogen sulfide and methane composes the laminar stagnation flow. In order to characterize this complex phenomenon with very specific chemical activities on the surface of the metallic plate, we propose a heterogeneous reaction scheme based on four reactions: two electrochemical, one adsorption and an additional exothermic reaction needed to complete the direct conversion of hydrogen sulfide to hydrogen on the surface of the iron. The nondimensional governing equations, which include the mass species and momentum conservation of the mixture and the molecular diffusion of hydrogen into the iron plate, are numerically solved by conventional finite-difference methods. The numerical results show the critical conditions of the H 2S decomposition as functions of the involved nondimensional parameters of the present model. In particular, we show parametrically the influence that has the initial concentration of H 2S on the surface coverage of the chemical products HS - H + and H 0 derived from the chemical and electrochemical reactions.

Martínez, J. C.; Méndez, F.; Treviño, C.

2006-12-01

369

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

EPA Science Inventory

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...

370

Density functional theory studies of the adsorption of hydrogen sulfide on aluminum doped silicane.  

PubMed

First principles total energy calculations have been performed to study the hydrogen sulfide (H2S) adsorption on silicane, an unusual one monolayer of Si(111) surface hydrogenated on both sides. The H2S adsorption may take place in dissociative or non-dissociative forms. Silicane has been considered as: (A) non-doped with a hydrogen vacancy, and doped in two main configurations; (B) with an aluminum replacing a hydrogen atom and (C-n; n?=?1, 2, 3) with an aluminum replacing a silicon atom at a lattice site. In addition, three supercells; 4x4, 3x3 and 2x2 have been explored for both non-doped and doped silicane. The non-dissociative adsorption takes place in geometries (A), (C-1), (C-2) and (C-3) while the dissociative in (B). Adsorption energies of the dissociative case are larger than those corresponding to the non-dissociated cases. In the dissociative adsorption, the molecule is fragmented in a HS structure and a H atom which are bonded to the aluminum to form a H-S-Al-H structure. The presence of the doping produces some electronic changes as the periodicity varies. Calculations of the total density of states (DOS) indicate that in most cases the energy gap decreases as the periodicity changes from 4x4 to 2x2. The features of the total DOS are explained in terms of the partial DOS. The reported charge density plots explain quite well the chemisorptions and physisorptions of the molecule on silicane in agreement with adsorption energies. PMID:23695768

Sánchez-Ochoa, Francisco; Guerrero-Sánchez, Jonathan; Canto, Gabriel I; Cocoletzi, Gregorio H; Takeuchi, Noboru

2013-08-01

371

Operational overview of the NASA GTE/CITE 3 airborne instrument intercomparisons for sulfur dioxide, hydrogen sulfide, carbonyl sulfide, dimethyl sulfide, and carbon disulfide  

NASA Technical Reports Server (NTRS)

This paper reports the overall experimental design and gives a brief overview of results from the third airborne Chemical Instrumentation Test and Evaluation (CITE 3) mission conducted as part of the National Aeronautics and Space Administration's Global Tropospheric Experiment. The primary objective of CITE 3 was to evaluate the capability of instrumentation for airborne measurements of ambient concentrations of SO2, H2S, CS, dimethyl sulfide, and carbonyl sulfide. Ancillary measurements augmented the intercomparison data in order to address the secondary objective of CITE 3 which was to address specific issues related to the budget and photochemistry of tropospheric sulfur species. The CITE 3 mission was conducted on NASA's Wallops Flight Center Electra aircraft and included a ground-based intercomparison of sulfur standards and intercomparison/sulfur science flights conducted from the NASA Wallops Flight Facility, Wallops Island, Virginia, followed by flights from Natal, Brazil. Including the transit flights, CITE 3 included 16 flights encompassing approximately 96 flight hours.

Hoell, James M., Jr.; Davis, Douglas D.; Gregory, Gerald L.; Mcneal, Robert J.; Bendura, Richard J.; Drewry, Joseph W.; Barrick, John D.; Kirchhoff, Volker W. J. H.; Motta, Adauto G.; Navarro, Roger L.

1993-01-01

372

Influence of support on the performance of molybdenum sulfide catalysts used to hydrotreat coal liquids  

SciTech Connect

Supports for molybdenum sulfide hydrotreating catalysts included silica, silica-magnesia, titania, chromia-alumina, activated carbon and nitrided activated carbon. The alumina supported Amocat 1A and Amocat 1C as well as the silica-alumina supported, Harshaw CoMo-0402 were also studied. Catalysts were characterized by BET surface area, mercury porosimetry and x-ray powder diffraction. Acidity was measured by the temperature programmed desorption of tert-butyl amine. Initial activity screening studies were conducted in a stirred autoclave batch reactor to determine appropriate metals loadings for the various supports. Initially active catalysts were then tested in a bench scale, trickle bed reactor to determine activity maintenance, coking tendency and selectivity at lined out conditions. Selectivities for hydrodenitrogenation and for the production of hydrogen donor molecules were of interest. The donatable hydrogen content of the produce was determined by {sup 1}H and {sup 13}C NMR spectroscopy. The results indicated a strong correlation between lined out hydrogenation activity and the volume in 60-200 {angstrom} diameter pores. A second correlation was observed between HDN activity and acid site density, indicating the importance of acid sites in denitrogenation. Low acidity catalysts appeared to produce a greater hydrogen donor content in the product oil than did high acidity catalysts but the results were not conclusive. The results also suggest that Bronsted acid sites can markedly reduce coking tendency but that in general, coke formation is related in a complex way to the acid/base chemistry of the surface.

McCormick, R.L.

1988-01-01

373

Hydrogen sulfide prolongs postharvest shelf life of strawberry and plays an antioxidative role in fruits.  

PubMed

Accumulating evidence shows that hydrogen sulfide (H(2)S) plays various physiological roles in plants, such as seed germination, root organogenesis, abiotic stress tolerance, and senescence of cut flowers. However, whether H(2)S participates in the regulation of ripening and senescence in postharvest fruits remains unknown. In the present study, the effect of H(2)S on postharvest shelf life and antioxidant metabolism in strawberry fruits was investigated. Fumigation with H(2)S gas released from the H(2)S donor NaHS prolonged postharvest shelf life of strawberry fruits in a dose-dependent manner. Strawberry fruits fumigated with various concentrations of H(2)S sustained significantly lower rot index, higher fruit firmness, and kept lower respiration intensity and polygalacturonase activities than controls. Further investigation showed that H(2)S treatment maintained higher activities of catalase, guaiacol peroxidase, ascorbate peroxidase, and glutathione reductase and lower activities of lipoxygenase relative to untreated controls. H(2)S also reduced malondialdehyde, hydrogen peroxide, and superoxide anion to levels below control fruits during storage. Moreover, H(2)S treatment maintained higher contents of reducing sugars, soluble proteins, free amino acid, and endogenous H(2)S in fruits. We interpret these data as indicating that H(2)S plays an antioxidative role in prolonging postharvest shelf life of strawberry fruits. PMID:22871304

Hu, Lan-Ying; Hu, Shu-Li; Wu, Jun; Li, Yan-Hong; Zheng, Ji-Lian; Wei, Zhao-Jun; Liu, Jian; Wang, Hui-Li; Liu, Yong-Sheng; Zhang, Hua

2012-09-01

374

Bile-acid-activated farnesoid X receptor regulates hydrogen sulfide production and hepatic microcirculation  

PubMed Central

AIM: To investigate whether the farnesoid X receptor (FXR) regulates expression of liver cystathionase (CSE), a gene involved in hydrogen sulfide (H2S) generation. METHODS: The regulation of CSE expression in response to FXR ligands was evaluated in HepG2 cells and in wild-type and FXR null mice treated with 6-ethyl chenodeoxycholic acid (6E-CDCA), a synthetic FXR ligand. The analysis demonstrated an FXR responsive element in the 5’-flanking region of the human CSE gene. The function of this site was investigated by luciferase reporter assays, chromatin immunoprecipitation and electrophoretic mobility shift assays. Livers obtained from rats treated with carbon tetrachloride alone, or in combination with 6-ethyl chenodeoxycholic acid, were studied for hydrogen sulphide generation and portal pressure measurement. RESULTS: Liver expression of CSE is regulated by bile acids by means of an FXR-mediated mechanism. Western blotting, qualitative and quantitative polymerase chain reaction, as well as immunohistochemical analysis, showed that expression of CSE in HepG2 cells and in mice is induced by treatment with an FXR ligand. Administration of 6E-CDCA to carbon tetrachloride treated rats protected against the down-regulation of CSE expression, increased H2S generation, reduced portal pressure and attenuated the endothelial dysfunction of isolated and perfused cirrhotic rat livers. CONCLUSION: These results demonstrate that CSE is an FXR-regulated gene and provide a new molecular explanation for the pathophysiology of portal hypertension.

Renga, Barbara; Mencarelli, Andrea; Migliorati, Marco; Distrutti, Eleonora; Fiorucci, Stefano

2009-01-01

375

The cystathionine ?-lyase/hydrogen sulfide system maintains cellular glutathione status.  

PubMed

Hydrogen sulfide (H2S) has been implicated to exhibit antioxidative properties in many models. CSE (cystathionine ?-lyase) is an important enzyme responsible for endogenous H2S production in mammalian systems, but little is known about the modulation of endogenous H2S production and its antioxidative activity. We found that inhibiting CSE activity with PAG (propargylglycine) or silencing CSE expression using an siRNA approach resulted in a greater reduction in cell viability under exposure to the oxidizing agent hydrogen peroxide (H2O2). Cellular oxidative stress also increased significantly upon PAG inhibition or CSE knockdown. Further experiments using an activity-null Y60A mutant, a hyperactive E339A mutant and a control E349A mutant demonstrated that modulation of CSE catalytic activity altered its antioxidative activity. The increased sensitivity towards H2O2-induced cytotoxicity in CSE-siRNA-transfected cells was associated with a decreased glutathione concentration (GSH) and glutathione ratio (GSH/GSSG). Incubation of cells with exogenous H2S increased the GSH concentration and GSH/GSSG ratio. Moreover, exogenous H2S preserved the cellular glutathione status under BSO (buthionine sulfoximine)-induced glutathione depletion. Taken together, the results of the present study provide molecular insights into the antioxidative activity of CSE and highlights the importance of the CSE/H2S system in maintaining cellular glutathione status. PMID:24707893

Lee, Zheng-Wei; Low, Yi-Lian; Huang, Shufen; Wang, Tianxiao; Deng, Lih-Wen

2014-06-15

376

The rotational spectrum of hydrogen sulfide: The H2S and H2S isotopologues revisited  

NASA Astrophysics Data System (ADS)

The rotational spectra of two isotopic species of hydrogen sulfide have been revisited. For H2S, which was detected in natural abundance, accurate measurements were performed in the submillimeter-wave region, from 500 GHz up to 1.56 THz, thus allowing improvement of the spectroscopic parameters as well as determination of new high-order centrifugal-distortion constants. The rotational spectrum of the main isotopologue was investigated in the millimeter- and submillimeter-wave region up to 1.6 THz, employing the Lamb-dip technique to obtain sub-Doppler resolution. As a consequence, transition frequencies at 1 THz were retrieved with an accuracy of 1 kHz and the hyperfine structure due to hydrogens was resolved, thus allowing the first determination of the spin–rotation tensor of H in H2S. Improved and new spectroscopic parameters were then provided that allow accurate predictions of rotational transitions up to 20 THz; in particular, the newly determined constants permit prediction of rotational transitions with J < 15, Ka<12 (up to about 10 THz) with expected uncertainties of a few hundreds of kHz.

Cazzoli, Gabriele; Puzzarini, Cristina

2014-04-01

377

Kinetics and mechanisms of iron sulfide reductions in hydrogen and in carbon monoxide  

USGS Publications Warehouse

The reduction of iron sulfides by hydrogen and by carbon monoxide has been studied using plug flow and thermogravimetric methods. The reactions were studied in the 523-723??K temperature range and were found to be first-order processes. Plug flow studies were used to correlate reaction rates between pyrite and the gases as a function of the surface area of the pyrite. The rate of H2S formation increases with the surface area of the pyrite sample. The results of thermogravimetric experiments indicate that the reactions consist of several steps. Rate constants for the pyrite reduction by H2 and by CO were obtained. The activation energies increased with degree of reduction. Values of Ea were 113.2 (step I) and 122.5 kJ/mole (step II) for pyrite reduction with CO and 99.4 (step I), 122.4 (step II), 125.2 (step III), and 142.6 kJ/mole (step IV) for pyrite reduction with hydrogen. ?? 1987.

Wiltowski, T.; Hinckley, C. C.; Smith, G. V.; Nishizawa, T.; Saporoschenko, M.; Shiley, R. H.; Webster, J. R.

1987-01-01

378

Regulation of hydrogen sulfide liberation in wine-producing Saccharomyces cerevisiae strains by assimilable nitrogen.  

PubMed Central

Saccharomyces cerevisiae wine-producing yeast cultures grown under model winemaking conditions could be induced to liberate hydrogen sulfide (H2S) by starvation for assimilable nitrogen. The amount of H2S produced was dependent on the yeast strain, the sulfur precursor compound, the culture growth rate, and the activity of the sulfite reductase enzyme (EC 1.8.1.2) immediately before nitrogen depletion. Increased H2S formation relative to its utilization by metabolism was not a consequence of a de novo synthesis of sulfite reductase. The greatest amount of H2S was produced when nitrogen became depleted during the exponential phase of growth or during growth on amino acids capable of supporting short doubling times. Both sulfate and sulfite were able to act as substrates for the generation of H2S in the absence of assimilable nitrogen; however, sulfate reduction was tightly regulated, leading to limited H2S liberation, whereas sulfite reduction appeared to be uncontrolled. In addition to ammonium, most amino acids were able to suppress the liberation of excess H2S when added as sole sources of nitrogen, particularly for one of the strains studied. Cysteine was the most notable exception, inducing the liberation of H2S at levels exceeding that of the nitrogen-depleted control. Threonine and proline also proved to be poor substitutes for ammonium. These data suggest that any compound that can efficiently generate sulfide-binding nitrogenous precursors of organic sulfur compounds will prevent the liberation of excess H2S.

Jiranek, V; Langridge, P; Henschke, P A

1995-01-01

379

Quality Determination of Liquid-Solid Hydrogen Mixtures.  

National Technical Information Service (NTIS)

Current interest in liquid-solid mixtures of parahydrogen ('slush hydrogen') as a potential rocket propellant lead to a theoretical and experimental investigation of one method of determining liquid-solid quality. It was found that measurement of the mass...

D. E. Daney D. B. Mann

1967-01-01

380

Novel Composite Hydrogen-Permeable Membranes for Non-Thermal Plasma Reactors for the Decomposition of Hydrogen Sulfide  

SciTech Connect

The goal of this experimental project is to design and fabricate a reactor and membrane test cell to dissociate hydrogen sulfide (H{sub 2}S) in a non-thermal plasma and recover hydrogen (H{sub 2}) through a superpermeable multi-layer membrane. Superpermeability of hydrogen atoms (H) has been reported by some researchers using membranes made of Group V transition metals (niobium, tantalum, vanadium, and their alloys), although it has yet to be confirmed in this study. A pulsed corona discharge (PCD) reactor has been fabricated and used to dissociate H{sub 2}S into hydrogen and sulfur. A nonthermal plasma cannot be produced in pure H{sub 2}S with our reactor geometry, even at discharge voltages of up to 30 kV, because of the high dielectric strength of pure H{sub 2}S ({approx}2.9 times higher than air). Therefore, H{sub 2}S was diluted in another gas with lower breakdown voltage (or dielectric strength). Breakdown voltages of H{sub 2}S in four balance gases (Ar, He, N{sub 2} and H{sub 2}) have been measured at different H{sub 2}S concentrations and pressures. Breakdown voltages are proportional to the partial pressure of H{sub 2}S and the balance gas. H{sub 2}S conversion and the reaction energy efficiency depend on the balance gas and H{sub 2}S inlet concentrations. With increasing H{sub 2}S concentrations, H{sub 2}S conversion initially increases, reaches a maximum, and then decreases. H{sub 2}S conversion in atomic balance gases, such as Ar and He, is more efficient than that in diatomic balance gases, such as N{sub 2} and H{sub 2}. These observations can be explained by the proposed reaction mechanism of H{sub 2}S dissociation in different balance gases. The results show that nonthermal plasmas are effective for dissociating H{sub 2}S into hydrogen and sulfur.

Morris D. Argyle; John F. Ackerman; Suresh Muknahallipatna; Jerry C. Hamann; Stanislaw Legowski; Guibling Zhao; Ji-Jun Zhang; Sanil John

2005-10-01

381

Variation in trace element content of magnetite crystallized from a fractionating sulfide liquid, Sudbury, Canada: Implications for provenance discrimination  

NASA Astrophysics Data System (ADS)

Laser ablation ICP-MS analysis has been applied to many accessory minerals in order to understand better the process by which the rock formed and for provenance discrimination. We have determined trace element concentrations of Fe-oxides in massive sulfides that form Ni-Cu-PGE deposits at the base of the Sudbury Igneous Complex in Canada. The samples represent the crystallization products of fractionating sulfide liquids and consist of early-forming Fe-rich monosulfide solution (MSS) cumulates and residual Cu-rich intermediate solid solution (ISS). This study shows that Fe-oxide geochemistry is a sensitive petrogenetic indicator for the degree of fractionation of the sulfide liquid and provides an insight into the partitioning of elements between sulfide and Fe-oxide phases. In addition, it is useful in determining the provenance of detrital Fe-oxide. In a sulfide melt, all lithophile elements (Cr, Ti, V, Al, Mn, Sc, Nb, Ga, Ge, Ta, Hf, W and Zr) are compatible into Fe-oxide. The concentrations of these elements are highest in the early-forming Fe-oxide (titanomagnetite) which crystallized with Fe-rich MSS. Upon the continual crystallization of Fe-oxide from the sulfide liquid, the lithophile elements gradually decrease so that late-forming Fe-oxide (magnetite), which crystallized from the residual Cu-rich liquid, is depleted in these elements. This behavior is in contrast with Fe-oxides that crystallized from a fractionating silicate melt, whereby the concentration of incompatible elements, such as Ti, increases rather than decreases. The behavior of the chalcophile elements in magnetite is largely controlled by the crystallization of the sulfide minerals with only Ni, Co, Zn, Mo, Sn and Pb present above detection limit in magnetite. Nickel, Mo and Co are compatible in Fe-rich MSS and thus the co-crystallizing Fe-oxide is depleted in these elements. In contrast, magnetite that crystallized later from the fractionated liquid with Cu-rich ISS is enriched in Ni, Mo and Co because Fe-rich MSS is absent. The concentrations of Sn and Pb, which are incompatible with Fe-rich MSS, are highest in magnetite that formed from the fractionated Cu-rich liquid. At subsolidus temperatures, ilmenite exsolved from titanomagnetite whereas Al-spinel exsolved from the cores of some magnetite, locally redistributing the trace elements. However, during laser ablation ICP-MS analysis of these Fe-oxides both the magnetite and its exsolution products are ablated so that the analysis represents the original magmatic composition of the Fe-oxide that crystallized from the sulfide melt.

Dare, Sarah A. S.; Barnes, Sarah-Jane; Beaudoin, Georges

2012-07-01

382

Partial Molar Volumes of Components and Species in O-S-Fe-Ni Oxide and Sulfide Liquids  

NASA Astrophysics Data System (ADS)

High-quality thermochemical models are now available for sulfide liquids at one bar pressure. An accurate description of the volume mixing properties of these liquids is required in order to apply these one-bar models to important problems at elevated pressure, including sulfide-hosted ore formation, sulfur cycling in convergent margin settings and core formation. Our experimental data have been combined with select density data from other laboratories to calibrate a comprehensive model for density and partial molar volumes of liquids in the O-S- Fe-Ni system. Our results indicate significant negative deviation from linear mixing across the Fe-S, Ni-S and Cu-S binaries. This result is in qualitative agreement with those from prior studies. In the context of associated homogeneous speciation models for sulfide liquids (Kress, 2000, 2007), this negative volume of mixing can be interpreted as a strongly negative volume of reaction for the formation for intermediate melt species from end member elemental components (? Vf). Our regression yields ? Vf values of -6.2, -9.4 and -9.1 cc/mol for FeS, NiS and CuS respectively. There is insufficient oxygen in experimental liquids to resolve a composition dependence for v¯O, but the unrealistic negative regressed value for oxygen partial molar volume suggests a negative ? Vf for FeO and FeO1.5. Partial molar volumes of Fe, Ni and Cu liquid species are calculated from Nash and Steinemann (1995). All other v¯i are assumed to be linear mixtures of component species volumes. This assumption also implies a moderate negative ? Vf for the species in question. The resulting model reproduces experimental densities from our laboratory with a 3.6% average error. This is comparable to the estimated measurement error. The larger 5.1% error for the full data set can be attributed to lower precision in some of the other studies and the effects of inter-laboratory error. The sulfide volume model can be applied to calculate thermochemical properties of sulfide liquids to moderate pressures. This model is used in conjunction with literature experiments on coexisting sulfide and silicate liquids at pressure to explore complex interactions between the pressure dependences of oxygen fugacity, sulfur fugacity and sulfide saturation.

Kress, V. C.

2007-12-01

383

Modeling liquid hydrogen cavitating flow with the full cavitation model  

Microsoft Academic Search

Cavitation is the formation of vapor bubbles within a liquid where flow dynamics cause the local static pressure to drop below the vapor pressure. This paper strives towards developing an effective computational strategy to simulate liquid hydrogen cavitation relevant to liquid rocket propulsion applications. The aims are realized by performing a steady state computational fluid dynamic (CFD) study of liquid

X. B. Zhang; L. M. Qiu; H. Qi; X. J. Zhang; Z. H. Gan

2008-01-01

384

Suicide Fads: Frequency and Characteristics of Hydrogen Sulfide Suicides in the United States  

PubMed Central

Objective: To assess the frequency of hydrogen sulfide (H2S) suicides and describe the characteristics of victims in the United States (U.S.) since the technique became common in Japan in 2007. Methods: To ascertain the frequency of intentional H2S related deaths in the U.S. prior to the start of the Japanese trend in 2007, we searched the multiple-cause-of-death data from the National Vital Statistics System. To collect as much information about the victims as possible, we sent an email to the National Association of Medical Examiners (NAME) listserv asking for their cooperation in identifying cases of H2S suicide. To identify cases that were not voluntarily reported by medical examiners but were reported by the media, we conducted Google searches using the search terms: “hydrogen sulfide suicide,” “H2S suicide,” “detergent suicide,” “chemical suicide,” and “suicide fad.” We obtained all available autopsy reports and abstracted information, including the site of the incident, the presence of a note warning others about the toxic gas and the demographic characteristics of the victims. We contacted medical examiners who potentially had custody of the cases that were identified through media reports and requested autopsies of these victims. When unable to obtain the autopsies, we gathered information from the media reports. Results: Forty-five deaths from H2S exposure occurred in the U.S. from 1999 to 2007, all unintentional. Responses from the NAME listserv yielded autopsy reports for 11 victims, and Google searches revealed an additional 19 H2S suicides in the U.S. since 2008. Overall (n=30), two cases were identified during 2008, 10 in 2009, and 18 in 2010. The majority of victims were white males, less than 30-years-old, left a warning note, and were found in cars. There were five reports of injuries to first responders, but no secondary fatalities. Conclusion: H2S suicides are increasing in the U.S., and their incidence is probably underestimated by public health officials and physicians. First responders are at risk when assessing these victims due to the severe toxicity of the gas. Emergency providers must be aware of H2S suicides to educate others and care for the rare survivor.

Reedy, Sarah Jane D.; Schwartz, Michael D.; Morgan, Brent W.

2011-01-01

385

Clean-up of low-concentration ventilation discharge from viscose manufacturing plants from carbon disulfide and hydrogen sulfide  

SciTech Connect

Three basic trends are described in cleaning up low-concentration discharges from carbon disulfide in order to protect the atmosphere from industrial contaminants: using activated carbon fabrics, alkalized activated carbons, or absorptive solution containing chemosorbents or catalysts. In the case where the third method is used, hydrogen sulfide is removed by use of the same absorptive solution which from carbon disulfide and hydrogen sulfide by using filters with new sorptive materials has been developed by the ''Khimvolokno'' NPO. The paper lists the important advantages fibrous sorptive materials have over granular sorbents. The highly developed sorbent surface reduces the dimensions of the gas-clean up equipment and offers the fundamental possibility of solving the problem of cleaning up large volumes of low concentration exhaust discharges. Results of the study show that the most effective method of purification is that which uses ion-exchange and carbon materials, and which requires developing filters of large unit capacity.

Shimko, I.G.; Chinennaya, S.K.; Katushkin, V.P.; Minster, V.S.; Pechalin, L.I.; Rybakov, L.A.; Zakirova, R.I.

1984-07-01

386

Solubility of hydrogen sulfide in pure water and in NaCl solutions, from 20 to 320°C and at saturation pressures  

Microsoft Academic Search

The solubility of hydrogen sulfide in pure water and in NaCl solutions has been studied experimentally from 20 to 320°C and at saturation pressures. Hydrogen sulfide solutions in equilibrium with their vapor phase were contained in a pressurized titanium bellows of known total volume. The bellows transmitted inside-vapor pressures via a thermally stable oil (pressure medium) to a high-precision pressure

O. M. Suleimenov; R. E. Krupp

1994-01-01

387

The influence of chemical composition and microstructure of API linepipe steels on hydrogen induced cracking and sulfide stress corrosion cracking  

Microsoft Academic Search

The chemical composition and microstructure are known to have a significant effect on the resistance to hydrogen induced cracking (HIC) and sulfide stress corrosion cracking (SSCC) of structural steels in wet H2S environments. In this paper, the influence of microstructure on HIC and SSCC behavior of two low C–Mn–Nb–Mo API linepipe steels has been investigated. Subjecting the steel to different

Rogério Augusto Carneiro; Rajindra Clement Ratnapuli; Vanessa de Freitas Cunha Lins

2003-01-01

388

Stress corrosion cracking of type 321 stainless steels in simulated petrochemical process environments containing hydrogen sulfide and chloride  

Microsoft Academic Search

The susceptibility to stress corrosion cracking (SCC) of type 321 stainless steel (type 321s) in a simulated petrochemical process environment containing hydrogen sulfide and chloride (20wt.% NaCl+0.01M Na2S2O3, pH 2) was assessed using the slow strain rate tensile (SSRT) test and static load (U-bend) tests at the free corrosion potentials. In the SSRT, effects of environmental factors, such as chloride

Y. Y. Chen; Y. M. Liou; H. C. Shih

2005-01-01

389

Influence of carbon, nickel, manganese, and vanadium on stress-corrosion cracking of steels in a medium containing hydrogen sulfide  

Microsoft Academic Search

conditions. We investigated the influence of carbon (0.03-0.45%), nickel (0.5-20%), manganese (1.0-16%), and vanadium (0.1-3.0%) on stress-corrosion cracking of steels in a 0.5% acetic acid solution saturated with hydrogen sulfide. In investigating the role of carbon, we remelted previously carburZzed carbonyl iron in a type SShVL vacuum furnace and cast it into primary ingots. The required quantity of carbon in

L. M. Karvatskii; R. I. Koval'chuk

1979-01-01

390

Transient behavior of biofilter inoculated with Thiobacillus sp. IW to treat waste-air containing hydrogen sulfide  

Microsoft Academic Search

Hydrogen sulfide is heavier than air and is colorless, toxic and flammable, the gas odor threshold of which is about 0.47\\u000a ppbv, which causes nuisance odor at concentrations as low as about 8ppbv and corrosion problems in sewer systems. The transient\\u000a behavior of biofilter packed with mixed media (of granular activated carbon and compost) inoculated with a pure culture of

Kwang-Hee Lim; Sang-Won Park

2006-01-01

391

A method of measuring the concentrations of hydrogen sulfide and ethyl mercaptan in their mixture in air  

Microsoft Academic Search

A method of measuring the concentrations of hydrogen sulfide and ethyl mercaptan in their mixture in air using a modified\\u000a gas-analyzer system based on an MOS-sensor, which operates on the basis of the difference in the temperatures at which these\\u000a gases burn, is considered. The use of these gas analyzers to monitor the odor level and to detect leakages of

A. V. Litvinov; P. O. Unichenko; I. N. Nikolaev

2007-01-01

392

Measurement and analysis of ammonia and hydrogen sulfide emissions from a mechanically ventilated swine confinement building in North Carolina  

Microsoft Academic Search

Emissions of atmospheric ammonia–nitrogen (NH3–N, where NH3–N=(1417)NH3) and hydrogen sulfide (H2S) were measured from a finishing swine confinement house at a commercial pig farm in eastern North Carolina. Continuous simultaneous NH3–N and H2S emissions were made for ?1-week period during four different seasons. The number of pigs contained in the house varied from ?850 to 900 with average weights ranging

Jessica Blunden; Viney P. Aneja; Phillip W. Westerman

2008-01-01

393

Direct inhibition of endothelial nitric oxide synthase by hydrogen sulfide: Contribution to dual modulation of vascular tension  

Microsoft Academic Search

We characterized actions of hydrogen sulfide (H2S) on tension of isolated rat and mouse aortae, and then examined if H2S could directly modulate activity of endothelial nitric oxide (NO) synthase (eNOS). Isometric tension was recorded in rat and mouse aortic rings. Activity of recombinant bovine eNOS was determined as conversion of [3H]-arginine into [3H]-citrulline. NaHS, a H2S donor, caused contraction

Satoko Kubo; Ichiko Doe; Yuko Kurokawa; Hiroyuki Nishikawa; Atsufumi Kawabata

2007-01-01

394

Solubility of mixtures of carbon dioxide and hydrogen sulfide in water + monoethanolamine + 2-amino-2-methyl-1-propanol  

Microsoft Academic Search

Solutions of amines are frequently used in gas treating processes to remove acid gases such as CO[sub 2] and H[sub 2]S from gas streams in the natural gas and synthetic ammonia industries and petroleum chemical plants. The solubilities of mixtures of carbon dioxide and hydrogen sulfide in water + monoethanolamine (MEA) + 2-amino-2-methyl-1-propanol (AMP) have been measured at 40 and

M. H. Li; B. C. Chang

2009-01-01

395

Influence of Stream Flow on Hydrogen Sulfide Concentrations and Distributions of Two Trout Species in a Rocky Mountains Tailwater  

Microsoft Academic Search

Geothermal springs in or adjacent to streams can contribute hydrogen sulfide (H 2S) and affect distributions of fish. We assessed the effects of H2S, relative to discharge, on the locations and movements of cutthroat trout Oncorhynchus clarki and brown trout Salmo trutta in a regulated river in northwestern Wyo- ming. Concentrations of H2S as low as 0.13 mg\\/L pre- vented

Matthew R. Dare; Wayne A. Hubert; Joseph S. Meyer

2001-01-01

396

Solubilities of mixtures of carbon dioxide and hydrogen sulfide in water + diethanolamine + 2-amino-2-methyl-1-propanol  

Microsoft Academic Search

The removal of acidic gases such as COâ, HâS, and COS from gas streams is an important operation in the natural gas and synthetic ammonia industries, oil refineries, and petrochemical chemical plants. The solubilities of mixtures of carbon dioxide and hydrogen sulfide in water + diethanolamine (DEA) + 2-amino-2-methyl-1-propanol (AMP) have been measured at 40 C and 80 C and

I-Shien Jane; Meng-Hui Li

1997-01-01

397

Cooperative rotation of alkylated sulfide molecules at the liquid-graphite interface.  

PubMed

Self-assembled monolayers of hexadecyl sulfide adsorbed on a graphite surface were studied using scanning tunneling microscopy (STM). STM images of the molecule indicate a bright spot and two relatively dim thin bands that correspond to the sulfur atom positioned at the center of the molecule and two alkyl chains that extend linearly from the sulfur atom, respectively. The contrast of the bands changes reversibly between the zigzag and aligned bright spots, which correspond to the zigzag methylene units of the alkyl chains; accordingly, the methylene units alternate between parallel and perpendicular orientations to the surface, respectively, on a time scale of minutes. The variation in contrast indicates cooperative rotation along the long axis of the molecules in the monolayer at the liquid-graphite interface. The reversibility of the contrast suggests that the solvent influences the difference in the free energies of the parallel and perpendicular configurations of the molecules with respect to the graphite surface. PMID:24734723

Hibino, Masahiro; Tsuchiya, Hiroshi

2014-04-01

398

A Raman and XPS investigation of supported molybdenum oxide thin films. 2. Reactions with hydrogen sulfide  

SciTech Connect

Surface characterization of supported molybdenum oxide thin films is undertaken following sulfidation treatments with H[sub 2]S. Surface characterization is carried out by in situ and ex situ laser Raman spectroscopy (LRS) and X-ray photoelectron spectroscopy (XPS). Sulfidation of thin-film molybdenum oxides supported on planar alumina and graphite produces two sulfides species: MoS[sub 2] and a reduced form with a binding energy lower than MoS[sub 2]. The S(2p) spectra also show polysulfide species at higher binding energies to MoS[sub 2]. Sulfidation of thicker, octahedral MoO[sub 3] thin films results only in MoS[sub 2]. Extensive prereduction of octahedral MoO[sub 2] prior to sulfidation is shown not to be important in the conversion of oxide to sulfide phases. 52 refs., 6 figs., 1 tab.

Spevack, P.A.; McIntyre, N.S. (Univ. of Western Ontario, London, Ontario (Canada))

1993-10-21

399

Case report: Profound neurobehavioral deficits in an oil field worker overcome by hydrogen sulfide  

SciTech Connect

A 24-year-old oil well tester was rendered semiconscious by hydrogen sulfide (H2S). He received oxygen and was hospitalized but released in 30 minutes. The next day, nausea, vomiting, diarrhea, and incontinence of urine and stool led to rehospitalization. These problems and leg shaking, dizziness, sweating, trouble sleeping, and nightmares prevented his return to work. A physical examination, chest x-ray, and pulmonary function tests were normal 39 months after the episode but vibration sense was diminished. Two choice visual reaction times were delayed. Balance was highly abnormal (5 to 6 cm/sec) with eyes closed. Blink reflex latency was slow (R-1 17.5 msec versus normal 14.3 msec). Numbers written on finger tips were not recognized. Verbal and visual recall were impaired but overlearned memory was intact. Cognitive functions measured by Culture Fair, block design, and digit symbol were impaired. Perceptual motor was slow. Scores for confusion, tension-anxiety, depression, and fatigue were elevated and vigor was reduced. Forty-nine months after exposure his reaction time, sway speed, and color vision had not improved. His recall and his cognitive, constructional, and psychomotor speeds had improved but remained abnormal. These deficits are most likely due to H2S. Similar testing of other survivors is recommended.

Kilburn, K.H. (Univ. of Southern California, Los Angeles (United States))

1993-11-01

400

Effect of hydrogen sulfide on restenosis of peripheral arteries after angioplasty.  

PubMed

Peripheral artery disease (PAD) may lead to a poor quality of life. Although percutaneous transluminal angioplasty (PTA) is widely used for the treatment of PAD, restenosis remains a major drawback. Hydrogen sulfide (H2S) plays potential roles in many physiological processes, such as vasodilatation and inhibition of smooth muscle cell proliferation. However, little is known regarding its role in arterial restenosis. In this study, we induced atherosclerotic-like lesions in rabbits, and we treated the rabbits with balloon angioplasty (BA) in a similar manner as PTA performed in the clinic. The rabbits were treated with sodium hydrosulfide (NaHS, a donor of H2S) or DL-propargylglycine (PPG, an inhibitor of H2S synthase). Treatment with NaHS significantly inhibited arterial restenosis following BA by reducing the intimal area and the intima/media ratio, while PPG treatment had a tendency to result in more severe restenosis. NaHS treatment significantly reduced smooth muscle cell (SMC) proliferation and elevated SMC apoptosis in the neointima. In contrast, PPG induced a significant increase in SMC proliferation. In conclusion, H2S attenuates the progression of neointimal hyperplasia and inhibits restenosis after BA. This discovery may lead to potential novel therapies, which can improve the prognosis of PAD patients. PMID:22470131

Ma, Bingbing; Liang, Gangzhu; Zhang, Fuxian; Chen, Yizhi; Zhang, Huan

2012-06-01

401

Hydrogen sulfide-releasing NSAIDs attenuate neuroinflammation induced by microglial and astrocytic activation.  

PubMed

Endogenously generated hydrogen sulfide (H(2)S) may have multiple functions in brain. It has been shown that H(2)S attenuates the expression of pro-inflammatory cytokines by lipopolysaccharide (LPS)-activated microglia. Here we demonstrate a neuroprotective effect of NaSH and three H(2)S-releasing compounds, ADT-OH, S-diclofenac, and S-aspirin. When activated by LPS and gamma-interferon, human microglia and THP-1 cells release materials that are toxic to human neuroblastoma SH-SY5Y cells. These phenomena also occur with gamma-interferon-stimulated human astroglia and U118 cells. When these cell types are pretreated with aspirin, diclofenac, NASH, or ADT-OH, the supernatants are significantly less toxic. When they are treated with the NSAID-H(2)S hybrid molecules S-diclofenac and S-aspirin, which are here referred to as S-NSAIDs, there is a significant enhancement of the protection. The effect is concentration and incubation time dependent. Such pretreatment also reduces the release of the proinflammatory mediators TNFalpha, IL-6, and nitric oxide. The H(2)S-releasing compounds are without effect when applied directly to SH-SY5Y cells. These data suggest that hybrid H(2)S releasing compounds have significant antiinflammatory properties and may be candidates for treating neurodegenerative disorders that have a prominent neuroinflammatory component such as Alzheimer disease and Parkinson disease. PMID:19544392

Lee, Moonhee; Sparatore, Anna; Del Soldato, Piero; McGeer, Edith; McGeer, Patrick L

2010-01-01

402

The effects of acute hydrogen sulfide poisoning on cytochrome p450 isoforms activity in rats.  

PubMed

Hydrogen sulfide (H2S) is the second leading cause of toxin related death (after carbon monoxide) in the workplace. H2S is absorbed by the upper respiratory tract mucosa, and it causes histotoxic hypoxemia and respiratory depression. Cocktail method was used to evaluate the influences of acute H2S poisoning on the activities of cytochrome P450 isoforms CYP2B6, CYP2D6, CYP3A4, CYP1A2, CYP2C19, and CYP2C9, which were reflected by the changes of pharmacokinetic parameters of six specific probe drugs, bupropion, metoprolol, midazolam, phenacetin, omeprazole, and tolbutamide, respectively. The experimental rats were randomly divided into two groups, control group and acute H2S poisoning group (inhaling 300?ppm for 2?h). The mixture of six probes was given to rats by oral administration and the blood samples were obtained at a series of time points through the caudal vein. The concentrations of probe drugs in rat plasma were measured by LC-MS. The results for acute H2S poisoning and control groups were as follows: there was a statistically significant difference in the AUC and C max for bupropion, metoprolol, phenacetin, and tolbutamide, while there was no statistical pharmacokinetic difference for midazolam and omeprazole. Acute H2S poisoning could inhibit the activity of CYP2B6, CYP2D6, CYP1A2, and CYP2C9 in rats. PMID:24790991

Wang, Xianqin; Chen, Mengchun; Chen, Xinxin; Ma, Jianshe; Wen, Congcong; Pan, Jianchun; Hu, Lufeng; Lin, Guanyang

2014-01-01

403

Actions of Hydrogen Sulfide on Sodium Transport Processes across Native Distal Lung Epithelia (Xenopus laevis)  

PubMed Central

Hydrogen sulfide (H2S) is well known as a highly toxic environmental chemical threat. Prolonged exposure to H2S can lead to the formation of pulmonary edema. However, the mechanisms of how H2S facilitates edema formation are poorly understood. Since edema formation can be enhanced by an impaired clearance of electrolytes and, consequently, fluid across the alveolar epithelium, it was questioned whether H2S may interfere with transepithelial electrolyte absorption. Electrolyte absorption was electrophysiologically measured across native distal lung preparations (Xenopus laevis) in Ussing chambers. The exposure of lung epithelia to H2S decreased net transepithelial electrolyte absorption. This was due to an impairment of amiloride-sensitive sodium transport. H2S inhibited the activity of the Na+/K+-ATPase as well as lidocaine-sensitive potassium channels located in the basolateral membrane of the epithelium. Inhibition of these transport molecules diminishes the electrochemical gradient which is necessary for transepithelial sodium absorption. Since sodium absorption osmotically facilitates alveolar fluid clearance, interference of H2S with the epithelial transport machinery provides a mechanism which enhances edema formation in H2S-exposed lungs.

Erb, Alexandra; Althaus, Mike

2014-01-01

404

OP04 Microbiota regulation of host hydrogen sulfide bioavailability and metabolism.  

PubMed

Hydrogen sulfide (H2S), generated through various endogenous enzymatic and nonenzymatic pathways, is emerging as a regulator of physiological and pathological events throughout the body. Bacteria in the gastrointestinal tract also produce significant amounts of H2S that regulates microflora growth and virulence responses. However, the impact of the microbiota on host global H2S bioavailability and metabolism remains unknown. To address this question, we examined H2S bioavailability in its various forms (free, acid labile, or bound sulfane sulfur), cystathionine ?-lyase (CSE) activity, and cysteine levels in tissues from germ-free versus conventionally housed mice. Free H2S levels were significantly reduced in plasma and gastrointestinal tissues of germ-free mice. Bound sulfane sulfur levels were decreased by 50-80% in germ-free mouse plasma and adipose and lung tissues. Tissue CSE activity was significantly reduced in many organs from germ-free mice, whereas tissue cysteine levels were significantly elevated compared to conventional mice. These data reveal that the microbiota profoundly regulates systemic bioavailability and metabolism of H2S. PMID:24948242

Shen, Xinggui; Carlström, Mattias; Borniquel, Sara; Jädert, Cecilia; Kevil, Christopher G; Lundberg, Jon

2013-09-01

405

The mechanism of hydrogen sulfide adsorption on fine rubber particle media (FRPM).  

PubMed

A commercial rubber waste product, fine rubber particle media (FRPM), was found to adsorb hydrogen sulfide (H?S) at 0.12 mg H?S/g FRPM of adsorption capacity. Since FRPM seems to be an attractive alternative to treat H?S owing to its economic advantages as well as its physicochemical characteristics, several analyses were conducted to investigate fundamental information, surface properties, and breakthrough characteristics of FRPM as adsorbent. The physical properties of FRPM including composition and surface chemistry were investigated to compare its performance with commonly available commercial H?S adsorbents such as activated carbon and assess the possible adsorption mechanism. The specific surface area of FRPM was less than 1% of activated carbon. FRPM does not have enough surface area supporting a pure physical adsorption of H?S because it is particulate in nature with limited porosity. The adsorption of FRPM to remove H?S was complex mechanism and involved a combination of zinc compounds and carbon black. PMID:23876257

Wang, Ning; Park, Jaeyoung; Ellis, Timothy G

2013-09-15

406

Emersion in the mangrove forest fish Rivulus marmoratus: A unique response to hydrogen sulfide  

SciTech Connect

The mangrove forest fish Rivulus marmoratus (Cyprinodontidae) has frequently been observed out of water, a phenomenon generally attributed to habitat drying. The hypothesis that hydrogen sulfide, a substance characteristically found in their environment, can serve as a stimulus for emersion, is tested in this study. In the field R. marmoratus was found in water with low to moderate level of H{sub 2}S. In the laboratory, R marmora leaped from water contaminated with H{sub 2}S at ecologically relevant concentrations. Aquatic hypoxia did not induce emersion, but prey capture did. Oxygen consumption by both juveniles and adults decreased significantly in air. These results suggest that avoidance of H{sub 2}S and the ability to survive terrestrial conditions enable this species to permanently occupy an area of the forest unavailable to other fishes. Furthermore, because a variety of stimuli lead to emersion in R. marmoratus, terrestriality in this species is likely a generalized response to environmental stress as well as a means of exploiting terrestrial resources. 16 refs., 1 fig., 2 tabs.

Abel, D.C.; Koenig, C.C.; Davis, W.P.

1987-01-01

407

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

PubMed

Activated carbon (AC) adsorption has long been considered to be a readily available technology for providing protection against exposure to acutely toxic gases. However, ACs without chemical impregnation have proven to be much less efficient than impregnated ACs in terms of gas removal. The impregnated ACs in current use are usually modified with metalloid impregnation agents (ASC-carbons; copper, chromium, or silver) to simultaneously enhance the chemical and physical properties of the ACs in removing specific poisonous gases. These metalloid agents, however, can cause acute poisoning to both humans and the environment, thereby necessitating the search for organic impregnation agents that present a much lower risk. The aim of the study reported here was to assess AC or ASC-carbon impregnated with triethylenediamine (TEDA) in terms of its adsorption capability for simulated hydrogen sulfide (H2S) and sulfur dioxide (SO2) gases. The investigation was undergone in a properly designed laboratory-scale and industrial fume hood evaluation. Using the system reported here, we obtained a significant adsorption: the removal capability for H2S and SO2 was 375 and 229 mg/g-C, respectively. BET measurements, element analysis, scanning electron microscopy, and energy dispersive spectrometry identified the removal mechanism for TEDA-impregnated AC to be both chemical and physical adsorption. Chemical adsorption and oxidation were the primary means by which TEDA-impregnated ASC-carbons removed the simulated gases. PMID:18200931

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

2007-12-01

408

Ferric Iron and Cobalt (III) compounds to safely decrease hydrogen sulfide in the body?  

PubMed

To sort out the putative roles of endogenous hydrogen sulfide (H2S) in clinical conditions wherein systemic inflammation or hypoxia is present, it becomes crucial to develop approaches capable of affecting H2S concentration that can be safely applied in humans. We have investigated a paradigm, which could achieve such a goal, using vitamin B12 (vit.B12), at the dose recommended in cyanide poisoning, and very low levels of methemoglobin (MetHb). Hydroxocobalamin in the plasma, supernatant of kidney, and heart tissue homogenates of rats that had received vit.B12 (140?mg.kg(-1) intravenous) was found in the ?M range. Exogenous H2S (100??M) added to the plasma or supernatants of these rats decreased at a significantly higher rate than in control rats. In the latter however a spontaneous oxidation of exogenous H2S occurred. In vitro, hydroxocobalamin solution (100??M) decreased, within <2?min, an equimolar concentration of H2S by 80%. Three to five percent MetHb prevented H2S induced hyperventilation in vivo and decreased exogenous H2S in vitro by 25-40??M within 30?s. Our observations lead to the hypothesis that innocuous levels of MetHb and vit.B12 could be a used as an effective and safe way to test the role of endogenous H2S in vivo. PMID:22233239

Van de Louw, Andry; Haouzi, Philippe

2013-08-10

409

Hydrogen Sulfide Lowers Proliferation and Induces Protective Autophagy in Colon Epithelial Cells  

PubMed Central

Hydrogen sulfide (H2S) is a gaseous bacterial metabolite that reaches high levels in the large intestine. In the present study, the effect of H2S on the proliferation of normal and cancerous colon epithelial cells was investigated. An immortalized colon epithelial cell line (YAMC) and a panel of colon cancer cell lines (HT-29, SW1116, HCT116) were exposed to H2S at concentrations similar to those found in the human colon. H2S inhibited normal and cancerous colon epithelial cell proliferation as measured by MTT assay. The anti-mitogenic effect of H2S was accompanied by G1-phase cell cycle arrest and the induction of the cyclin-dependent kinase inhibitor p21Cip. Moreover, exposure to H2S led to features characteristic of autophagy, including increased formation of LC3B+ autophagic vacuoles and acidic vesicular organelles as determined by immunofluorescence and acridine orange staining, respectively. Abolition of autophagy by RNA interference targeting Vps34 or Atg7 enhanced the anti-proliferative effect of H2S. Further mechanistic investigation revealed that H2S stimulated the phosphorylation of AMP-activated protein kinase (AMPK) and inhibited the phosphorylation of mammalian target of rapamycin (mTOR) and S6 kinase. Inhibition of AMPK significantly reversed H2S-induced autophagy and inhibition of cell proliferation. Collectively, we demonstrate that H2S inhibits colon epithelial cell proliferation and induces protective autophagy via the AMPK pathway.

Yu, Le; Chan, Francis K. L.; Cheng, Alfred S. L.; Yu, Jun; Sung, Joseph J. Y.; Wu, William K. K.; Cho, Chi H.

2012-01-01

410

Detection of hydrogen sulfide through photoluminescence quenching of penicillamine-copper nanocluster aggregates  

NASA Astrophysics Data System (ADS)

We have developed a one-pot, inexpensive, simple and rapid method to synthesize photoluminescent copper nanocluster (Cu NC) aggregates from Cu2+ ions in 65% (v v?1) dimethylformamide aqueous solution containing penicillamine (PA) as a capping and reducing agent. As-prepared PA-Cu NC aggregates emit at 580 nm when excited at 326 nm, with a quantum yield of 2.0%. The photoluminescence of PA-Cu NC aggregates originate from ligand-to-metal charge transfer, which is supported by a long lifetime (126.5 ns) and a large Stokes shift (254 nm). As-prepared PA-Cu NC aggregates have different emission wavelengths with the same excitation wavelength in various organic-aqueous solutions. The PA-Cu NC aggregates are highly selective and sensitive to the detection of hydrogen sulfide (H2S), based on analyte-induced photoluminescence quenching through the formation of CuS nanoparticles. The probe allows the detection of H2S, with a linear range of 1–100 ?M and a limit of detection (signal-to-noise ratio = 3) of 500 nM. The practicality of this probe has been validated through the analysis of hot spring water samples.

Ma, Jia-Ying; Chen, Po-Cheng; Chang, Huan-Tsung

2014-05-01

411

Hydrogen sulfide augments synaptic neurotransmission in the nucleus of the solitary tract.  

PubMed

Within the brain stem, the nucleus tractus solitarii (NTS) serves as a principal central site for sensory afferent integration from the cardiovascular and respiratory reflexes. Neuronal activity and synaptic transmission in the NTS are highly pliable and subject to neuromodulation. In the central nervous system, hydrogen sulfide (H?S) is a gasotransmitter generated primarily by the enzyme cystathionine-?-synthase (CBS). We sought to determine the role of H?S, and its generation by CBS, in NTS excitability. Real-time RT-PCR, immunoblot, and immunohistochemistry analysis identified the presence of CBS in the NTS. Patch-clamp electrophysiology in brain stem slices examined excitatory postsynaptic currents (EPSCs) and membrane properties in monosynaptically driven NTS neurons. Confocal imaging of labeled afferent synaptic terminals in NTS slices monitored intracellular calcium. Exogenous H?S significantly increased the amplitude of evoked solitary tract (TS)-EPSCs, frequency of miniature (m)EPSCs, and presynaptic terminal calcium fluorescence in the NTS. H?S did not alter action potential discharge or postsynaptic properties. On the other hand, the CBS inhibitor aminooxyacetate (AOA) significantly reduced the amplitude of TS-EPSCs and presynaptic terminal calcium fluorescence in the NTS without altering postsynaptic properties. Taken together, these data support a presynaptic role for endogenous H?S in modulation of excitatory neurotransmission in the NTS. PMID:21734104

Austgen, James R; Hermann, Gerlinda E; Dantzler, Heather A; Rogers, Richard C; Kline, David D

2011-10-01

412

C. elegans aging is modulated by hydrogen sulfide and the sulfhydrylase/cysteine synthase cysl-2.  

PubMed

Exogenous hydrogen sulfide (H2S) administration and endogenous H2S metabolism were explored in the nematode C. elegans. Chronic treatment with a slow-releasing H2S donor, GYY4137, extended median survival by 17-23% and increased tolerance towards oxidative and endoplasmic reticulum (ER) stress. Also, cysl-2, a sulfhydrylase/cysteine synthase in C. elegans, was transcriptionally upregulated by GYY4137 treatment and the deletion of cysl-2 resulted in a significant reduction in lifespan which was partially recovered by the supplementation of GYY4137. Likewise, a mammalian cell culture system, GYY4137 was able to protect bovine aortic endothelial cells (BAECs) from oxidative stress and (H2O2)-induced cell death. Taken together, this provides further support that H2S exerts a protective function which is consistent with the longevity dividend theory. Overall, this study underlines the therapeutic potential of a slow-releasing H2S donor as regulators of the aging and cellular stress pathways. PMID:24260346

Qabazard, Bedoor; Ahmed, Samanza; Li, Ling; Arlt, Volker M; Moore, Philip K; Stürzenbaum, Stephen R

2013-01-01

413

Hydrogen Sulfide Ameliorates Ischemia/Reperfusion-Induced Hepatitis by Inhibiting Apoptosis and Autophagy Pathways  

PubMed Central

Background. Hepatic ischemia/reperfusion (I/R) injury is an important clinical problem, and its consequences can seriously threaten human health. Apoptosis and autophagy have been shown to contribute to cell death in hepatic I/R injury. Hydrogen sulfide (H2S) is the third most common endogenously produced gaseous signaling molecule and is known to exert a protective effect against hepatic I/R injury. In this study, the purpose is to explore both the effect and mechanism of H2S on hepatic I/R injury. Methods. Balb/c mice were randomized into Sham, I/R, or two doses (14??mol/kg and 28??mol/kg) of sodium hydrosulfide (NaHS, an H2S donor) preconditioning groups. Results. NaHS significantly reduced the levels of TNF-? and IL-6 at 12?h and 24?h after injection compared with ischemia/reperfusion challenge alone. The expression of Bcl-2, Bax, Beclin-1, and LC3, which play important roles in the regulation of the apoptosis and autophagy pathways, was also clearly affected by NaHS. Furthermore, NaHS affected the p-JNK1, p-ERK1, and p-p38. Conclusion. Our results indicate that H2S attenuates hepatic I/R injury, at least in part, by regulating apoptosis through inhibiting JNK1 signaling. The autophagy agonist rapamycin potentiated this hepatoprotective effect by reversing the inhibition of autophagy by H2S.

Cheng, Ping; Wang, Fan; Chen, Kan; Shen, Miao; Dai, Weiqi; Xu, Ling; Zhang, Yan; Wang, Chengfen; Li, Jingjing; Yang, Jing; Zhu, Rong; Zhang, Huawei; Zheng, Yuanyuan; Lu, Jie; Zhou, Yingqun; Guo, Chuanyong

2014-01-01

414

Discrimination of the oral microbiota associated with high hydrogen sulfide and methyl mercaptan production.  

PubMed

Both hydrogen sulfide (H2S) and methyl mercaptan (CH(3)SH) are frequently detected in large amounts in malodorous mouth air. We investigated the bacterial composition of saliva of 30 subjects with severe oral malodor exhibiting extreme CH(3)SH/H(2)S ratios (high H(2)S but low CH(3)SH concentrations, n 5 14; high CH(3)SH but low H2S concentrations, n 5 16) and 13 subjects without malodor, using barcoded pyrosequencing analysis of the 16S rRNA gene. Phylogenetic community analysis with the UniFrac distance metric revealed a distinct bacterial community structure in each malodor group. The H2S group showed higher proportions of the genera Neisseria, Fusobacterium, Porphyromonas and SR1 than the other two groups, whereas the CH(3)SH group had higher proportions of the genera Prevotella, Veillonella,Atopobium, Megasphaera, and Selenomonas. Our results suggested that distinct bacterial populations in the oral microbiota are involved in production of high levels of H2S and CH3SH in the oral cavity. PMID:22355729

Takeshita, Toru; Suzuki, Nao; Nakano, Yoshio; Yasui, Masaki; Yoneda, Masahiro; Shimazaki, Yoshihiro; Hirofuji, Takao; Yamashita, Yoshihisa

2012-01-01

415

Hydrogen sulfide deactivates common nitrobenzofurazan-based fluorescent thiol labeling reagents.  

PubMed

Sulfhydryl-containing compounds, including thiols and hydrogen sulfide (H2S), play important but differential roles in biological structure and function. One major challenge in separating the biological roles of thiols and H2S is developing tools to effectively separate the reactivity of these sulfhydryl-containing compounds. To address this challenge, we report the differential responses of common electrophilic fluorescent thiol labeling reagents, including nitrobenzofurazan-based scaffolds, maleimides, alkylating agents, and electrophilic aldehydes, toward cysteine and H2S. Although H2S reacted with all of the investigated scaffolds, the photophysical response to each scaffold was significantly different. Maleimide-based, alkylating, and aldehydic thiol labeling reagents provided a diminished fluorescence response when treated with H2S. By contrast, nitrobenzofurazan-based labeling reagents were deactivated by H2S addition. Furthermore, the addition of H2S to thiol-activated nitrobenzofurazan-based reagents reduced the fluorescence signal, thus establishing the incompatibility of nitrobenzofurazan-based thiol labeling reagents in the presence of H2S. Taken together, these studies highlight the differential reactivity of thiols and H2S toward common thiol-labeling reagents and suggest that sufficient care must be taken when labeling or measuring thiols in cellular environments that produce H2S due to the potential for both false-positive and eroded responses. PMID:24852143

Montoya, Leticia A; Pluth, Michael D

2014-06-17

416

Genetic Targets of Hydrogen Sulfide in Ventilator-Induced Lung Injury - A Microarray Study  

PubMed Central

Recently, we have shown that inhalation of hydrogen sulfide (H2S) protects against ventilator-induced lung injury (VILI). In the present study, we aimed to determine the underlying molecular mechanisms of H2S-dependent lung protection by analyzing gene expression profiles in mice. C57BL/6 mice were subjected to spontaneous breathing or mechanical ventilation in the absence or presence of H2S (80 parts per million). Gene expression profiles were determined by microarray, sqRT-PCR and Western Blot analyses. The association of Atf3 in protection against VILI was confirmed with a Vivo-Morpholino knockout model. Mechanical ventilation caused a significant lung inflammation and damage that was prevented in the presence of H2S. Mechanical ventilation favoured the expression of genes involved in inflammation, leukocyte activation and chemotaxis. In contrast, ventilation with H2S activated genes involved in extracellular matrix remodelling, angiogenesis, inhibition of apoptosis, and inflammation. Amongst others, H2S administration induced Atf3, an anti-inflammatory and anti-apoptotic regulator. Morpholino mediated reduction of Atf3 resulted in elevated lung injury despite the presence of H2S. In conclusion, lung protection by H2S during mechanical ventilation is associated with down-regulation of genes related to oxidative stress and inflammation and up-regulation of anti-apoptotic and anti-inflammatory genes. Here we show that Atf3 is clearly involved in H2S mediated protection.

Spassov, Sashko; Pfeifer, Dietmar; Strosing, Karl; Ryter, Stefan; Hummel, Matthias; Faller, Simone; Hoetzel, Alexander

2014-01-01

417

Role of hydrogen sulfide in the formalin-induced orofacial pain in rats.  

PubMed

Hydrogen sulfide (H2S) is a gasotransmitter synthesized in peripheral tissues by the enzyme cystathionine gamma-lyase (CSE). This gas has been documented to be involved in a wide variety of processes including inflammation and nociception. The aim of the present study was to investigate the role of the peripheral H2S pathway in nociceptive response to the orofacial formalin experimental model of pain. Orofacial pain was induced by subcutaneous injection of formalin (1.5%, 50µl) into the upper lip of rats, and the time spent rubbing the face was measured at 3-min intervals for 45min. Formalin induced a marked biphasic pain (first phase: 0-3min; second phase: 15-33min). Pretreatment with H2S donor (Na2S; 90µmol/kg), CSE inhibitor (propargylglycine; 26.5 and 88.4µmol/kg), or a preferential blocker of T-type Ca(2+) channels (mibefradil; 0.28 and 2.81µmol/kg) attenuated the second phase of face rubbing when injected locally as well as systemically. Pretreatment with a selective blocker of K(+)ATP channels (glybenclamide; 2.81µmol/kg) suppressed the Na2S-mediated attenuation of the formalin-induced pain second phase. Taken together these results suggest that endogenously produced H2S plays a pronociceptive role probably via T-type Ca(2+) channels, whereas exogenous H2S exerts antinociceptive effects mediated by K(+)ATP channels. PMID:24876060

Donatti, Alberto F; Araujo, Rebeca M; Soriano, Renato N; Azevedo, Leopoldo U; Leite-Panissi, Christie A; Branco, Luiz G S

2014-09-01

418

Regulation of mitochondrial bioenergetic function by hydrogen sulfide. Part II. Pathophysiological and therapeutic aspects.  

PubMed

Emerging work demonstrates the dual regulation of mitochondrial function by hydrogen sulfide (H2 S), including, at lower concentrations, a stimulatory effect as an electron donor, and, at higher concentrations, an inhibitory effect on cytochrome C oxidase. In the current article, we overview the pathophysiological and therapeutic aspects of these processes. During cellular hypoxia/acidosis, the inhibitory effect of H2 S on complex IV is enhanced, which may shift the balance of H2 S from protective to deleterious. Several pathophysiological conditions are associated with an overproduction of H2 S (e.g. sepsis), while in other disease states H2 S levels and H2 S bioavailability are reduced and its therapeutic replacement is warranted (e.g. diabetic vascular complications). Moreover, recent studies demonstrate that colorectal cancer cells up-regulate the H2 S-producing enzyme cystathionine ?-synthase (CBS), and utilize its product, H2 S, as a metabolic fuel and tumour-cell survival factor; pharmacological CBS inhibition or genetic CBS silencing suppresses cancer cell bioenergetics and suppresses cell proliferation and cell chemotaxis. In the last chapter of the current article, we overview the field of H2 S-induced therapeutic 'suspended animation', a concept in which a temporary pharmacological reduction in cell metabolism is achieved, producing a decreased oxygen demand for the experimental therapy of critical illness and/or organ transplantation. PMID:23991749

Módis, Katalin; Bos, Eelke M; Calzia, Enrico; van Goor, Harry; Coletta, Ciro; Papapetropoulos, Andreas; Hellmich, Mark R; Radermacher, Peter; Bouillaud, Frédéric; Szabo, Csaba

2014-04-01

419

Detection of hydrogen sulfide through photoluminescence quenching of penicillamine-copper nanocluster aggregates.  

PubMed

We have developed a one-pot, inexpensive, simple and rapid method to synthesize photoluminescent copper nanocluster (Cu NC) aggregates from Cu(2+) ions in 65% (v v(-1)) dimethylformamide aqueous solution containing penicillamine (PA) as a capping and reducing agent. As-prepared PA-Cu NC aggregates emit at 580 nm when excited at 326 nm, with a quantum yield of 2.0%. The photoluminescence of PA-Cu NC aggregates originate from ligand-to-metal charge transfer, which is supported by a long lifetime (126.5 ns) and a large Stokes shift (254 nm). As-prepared PA-Cu NC aggregates have different emission wavelengths with the same excitation wavelength in various organic-aqueous solutions. The PA-Cu NC aggregates are highly selective and sensitive to the detection of hydrogen sulfide (H2S), based on analyte-induced photoluminescence quenching through the formation of CuS nanoparticles. The probe allows the detection of H2S, with a linear range of 1-100 ?M and a limit of detection (signal-to-noise ratio = 3) of 500 nM. The practicality of this probe has been validated through the analysis of hot spring water samples. PMID:24762432

Ma, Jia-Ying; Chen, Po-Cheng; Chang, Huan-Tsung

2014-05-16

420

Measurements of atmospheric dimethylsulfide, hydrogen sulfide, and carbon disulfide during GTE/CITE 3  

NASA Astrophysics Data System (ADS)

Measurements of atmospheric dimethylsulfide (DMS), hydrogen sulfide (H2S), and carbon disulfide (CS2) were made over the North and South Atlantic Ocean as part of the Global Tropospheric Experiment/Chemical Instrumentation Test and Evaluation (GTE/CITE 3) project. DMS and CS2 samples were collected and analyzed using an automated gas chromatography/flame photometric detection system with a sampling frequency of 10 min. H2S samples were collected using silver nitrate impregnated filters and analyzed by fluorescence quenching. The DMS data from both hemispheres have a bimodal distribution. Over the North Atlantic this reflects the difference between marine and continental air masses. Over the South Atlantic it may reflect differences in the sea surface source of DMS, corresponding to different air mass source regions. The median boundary layer H2S and CS2 levels were significantly higher in the northern hemisphere than the southern hemisphere, reflecting the higher frequency of samples influenced by pollutant and/or coastal emissions. Composite vertical profiles of DMS and H2S are similar to each other, and are consistent with a sea surface source. Vertical profiles of CS2 have maxima in the free troposphere, implicating a continental source. The low levels of H2S and CS2 found in the southern hemisphere constrain the role of these compounds in global budgets to significantly less than previously estimated.

Cooper, David J.; Saltzman, Eric S.

1993-12-01

421

Hydrogen sulfide attenuates hepatic ischemia-reperfusion injury: role of antioxidant and antiapoptotic signaling  

PubMed Central

Hydrogen sulfide (H2S) is an endogenously produced gaseous signaling molecule with diverse physiological activity. The potential protective effects of H2S have not been evaluated in the liver. The purpose of the current study was to investigate if H2S could afford hepatoprotection in a murine model of hepatic ischemia-reperfusion (I/R) injury. Hepatic injury was achieved by subjecting mice to 60 min of ischemia followed by 5 h of reperfusion. H2S donor (IK1001) or vehicle were administered 5 min before reperfusion. H2S attenuated the elevation in serum alanine aminotransferase (ALT) by 68.6% and aspartate aminotransferase (AST) by 70.8% compared with vehicle group. H2S-mediated cytoprotection was associated with an improved balance between reduced glutathione (GSH) vs. oxidized glutathione (GSSG), an attenuated formation of lipid hydroperoxides, and an increased expression of thioredoxin-1 (Trx-1). Furthermore, H2S inhibited the progression of apoptosis after I/R injury by increasing the protein expression of heat shock protein (HSP-90) and Bcl-2. These results indicate that H2S protects the murine liver against I/R injury through an upregulation of intracellular antioxidant and antiapoptotic signaling pathways.

Jha, Saurabh; Calvert, John W.; Duranski, Mark R.; Ramachandran, Arun; Lefer, David J.

2008-01-01

422

Hydrogen sulfide attenuates myocardial ischemia-reperfusion injury by preservation of mitochondrial function  

PubMed Central

The recent discovery that hydrogen sulfide (H2S) is an endogenously produced gaseous second messenger capable of modulating many physiological processes, much like nitric oxide, prompted us to investigate the potential of H2S as a cardioprotective agent. In the current study, we demonstrate that the delivery of H2S at the time of reperfusion limits infarct size and preserves left ventricular (LV) function in an in vivo model of myocardial ischemia-reperfusion (MI-R). This observed cytoprotection is associated with an inhibition of myocardial inflammation and a preservation of both mitochondrial structure and function after I-R injury. Additionally, we show that modulation of endogenously produced H2S by cardiac-specific overexpression of cystathionine ?-lyase (?-MHC-CGL-Tg mouse) significantly limits the extent of injury. These findings demonstrate that H2S may be of value in cytoprotection during the evolution of myocardial infarction and that either administration of H2S or the modulation of endogenous production may be of clinical benefit in ischemic disorders.

Elrod, John W.; Calvert, John W.; Morrison, Joanna; Doeller, Jeannette E.; Kraus, David W.; Tao, Ling; Jiao, Xiangying; Scalia, Rosario; Kiss, Levente; Szabo, Csaba; Kimura, Hideo; Chow, Chi-Wing; Lefer, David J.

2007-01-01

423

The sorption of hydrogen sulfide from hot syngas by metal oxides over supports.  

PubMed

Six 5 wt.% metal sorbents including Mn, Fe, Cu, Co, Ce and Zn supported on gamma-Al2O3, prepared by the incipient wetness impregnation method with calcination at 700 degrees C for 2 h, have been investigated for sorption of hydrogen sulfide in the temperature range of 500-700 degrees C. The sorption experiments were conducted in a fixed-bed reactor in terms of breakthrough curves and characterized by X-ray powder diffraction. The results reveal that the copper and manganese sorbents exhibit the best performance because they provide nearly 100% utilization, but the copper sorbent has a lower sulfur sorption capacity compared with the manganese sorbent. The zinc and cerium sorbents are not good candidates attributed to the vaporization of zinc and unexpected product for cerium. Effects of support materials on 5 wt.% manganese were also investigated by using gamma-Al2O3, SiO2 and TiO2 in this study. Five weight percent Mn/gamma-Al2O3 shows the best performance among support candidates. On the basis of XRPD and BET surface area analysis, TiO2 appears a huge loss in BET surface area associated with a significant formation of rutile form. PMID:15620738

Ko, Tzu-Hsing; Chu, Hsin; Chaung, Lung-Kai

2005-01-01

424

Rare isotopic species of hydrogen sulfide: the rotational spectrum of H236S  

NASA Astrophysics Data System (ADS)

The rotational spectrum of the 36S-bearing isotopologue of hydrogen sulfide (H2S) has been investigated for the first time in the 167 GHz-1.6 THz frequency range, thus providing an accurate and reliable set of spectroscopic parameters. The experimental investigation was backed up by state-of-the-art quantum-chemical calculations, which also allowed us to demonstrate the incorrectness of the previously reported spectroscopic constants. The present results are of suitable accuracy to attempt the astrophysical detection of the isotopic species under consideration. Finally, reliable predictions for the spectroscopic constants of other rare isotopologues of H2S, namely the mono- and bi-deuterated species containing 33S and 34S, are provided. The complete list of measured transitions is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/566/A52

Cazzoli, Gabriele; Puzzarini, Cristina; Gauss, Jürgen

2014-06-01

425

C. elegans Aging Is Modulated by Hydrogen Sulfide and the sulfhydrylase/cysteine Synthase cysl-2  

PubMed Central

Exogenous hydrogen sulfide (H2S) administration and endogenous H2S metabolism were explored in the nematode C. elegans. Chronic treatment with a slow-releasing H2S donor, GYY4137, extended median survival by 17-23% and increased tolerance towards oxidative and endoplasmic reticulum (ER) stress. Also, cysl-2, a sulfhydrylase/cysteine synthase in C. elegans, was transcriptionally upregulated by GYY4137 treatment and the deletion of cysl-2 resulted in a significant reduction in lifespan which was partially recovered by the supplementation of GYY4137. Likewise, a mammalian cell culture system, GYY4137 was able to protect bovine aortic endothelial cells (BAECs) from oxidative stress and (H2O2)-induced cell death. Taken together, this provides further support that H2S exerts a protective function which is consistent with the longevity dividend theory. Overall, this study underlines the therapeutic potential of a slow-releasing H2S donor as regulators of the aging and cellular stress pathways.

Qabazard, Bedoor; Ahmed, Samanza; Li, Ling; Arlt, Volker M.; Moore, Philip K.; Sturzenbaum, Stephen R.

2013-01-01

426

A fatal work-related poisoning by hydrogen sulfide: report on a case.  

PubMed

Hydrogen sulfide (H2S) is a colorless and potentially deadly gas that may cause rapid loss of consciousness and respiratory depression without warning. Although occupational exposure to H2S and the medical management of H2S-associated toxicity are widely established, it remains a problem in the sour gas industry and in other industrial settings, predominantly in new workers. In this article, the authors report a fatal case of a factory worker who died after breathing in H2S while undertaking a task that he was not trained to perform. Toxicological assessment supported by autopsy findings and circumstantial data was essential to clarify the cause of death, determined as H2S poisoning. This case emphasizes the need to develop work safety initiatives, improve on-the-job training, and introduce more consciousness to put on protective equipment for workers; indeed, correct training and education for workers regarding safety in the workplace may help to reduce worker fatalities. PMID:24196727

Lancia, Massimo; Panata, Laura; Tondi, Verdiana; Carlini, Luigi; Bacci, Mauro; Rossi, Riccardo

2013-12-01

427

Highly sensitive hydrogen sulfide (H2 S) gas sensors from viral-templated nanocrystalline gold nanowires  

NASA Astrophysics Data System (ADS)

A facile, site-specific viral-templated assembly method was used to fabricate sensitive hydrogen sulfide (H2S) gas sensors at room temperature. A gold-binding M13 bacteriophage served to organize gold nanoparticles into linear arrays which were used as seeds for subsequent nanowire formation through electroless deposition. Nanowire widths and densities within the sensors were modified by electroless deposition time and phage concentration, respectively, to tune device resistance. Chemiresistive H2S gas sensors with superior room temperature sensing performance were produced with sensitivity of 654%/ppmv, theoretical lowest detection limit of 2 ppbv, and 70% recovery within 9 min for 0.025 ppmv. The role of the viral template and associated gold-binding peptide was elucidated by removing organics using a short O2 plasma treatment followed by an ethanol dip. The template and gold-binding peptide were crucial to electrical and sensor performance. Without surface organics, the resistance fell by several orders of magnitude, the sensitivity dropped by more than a factor of 100 to 6%/ppmv, the lower limit of detection increased, and no recovery was detected with dry air flow. Viral templates provide a novel, alternative fabrication route for highly sensitive, nanostructured H2S gas sensors.

Moon, Chung Hee; Zhang, Miluo; Myung, Nosang V.; Haberer, Elaine D.

2014-04-01

428

The Effects of Acute Hydrogen Sulfide Poisoning on Cytochrome P450 Isoforms Activity in Rats  

PubMed Central

Hydrogen sulfide (H2S) is the second leading cause of toxin related death (after carbon monoxide) in the workplace. H2S is absorbed by the upper respiratory tract mucosa, and it causes histotoxic hypoxemia and respiratory depression. Cocktail method was used to evaluate the influences of acute H2S poisoning on the activities of cytochrome P450 isoforms CYP2B6, CYP2D6, CYP3A4, CYP1A2, CYP2C19, and CYP2C9, which were reflected by the changes of pharmacokinetic parameters of six specific probe drugs, bupropion, metoprolol, midazolam, phenacetin, omeprazole, and tolbutamide, respectively. The experimental rats were randomly divided into two groups, control group and acute H2S poisoning group (inhaling 300?ppm for 2?h). The mixture of six probes was given to rats by oral administration and the blood samples were obtained at a series of time points through the caudal vein. The concentrations of probe drugs in rat plasma were measured by LC-MS. The results for acute H2S poisoning and control groups were as follows: there was a statistically significant difference in the AUC and Cmax for bupropion, metoprolol, phenacetin, and tolbutamide, while there was no statistical pharmacokinetic difference for midazolam and omeprazole. Acute H2S poisoning could inhibit the activity of CYP2B6, CYP2D6, CYP1A2, and CYP2C9 in rats.

Wang, Xianqin; Chen, Mengchun; Chen, Xinxin; Ma, Jianshe; Wen, Congcong; Pan, Jianchun; Hu, Lufeng; Lin, Guanyang

2014-01-01

429

Protective Role of Hydrogen Sulfide against Noise-Induced Cochlear Damage: A Chronic Intracochlear Infusion Model  

PubMed Central

Background A reduction in cochlear blood flow plays an essential role in noise-induced hearing loss (NIHL). The timely regulation of cochlear perfusion determines the progression and prognosis of NIHL. Hydrogen sulfide (H2S) has attracted increasing interest as a vasodilator in cardiovascular systems. This study identified the role of H2S in cochlear blood flow regulation and noise protection. Methodology/Principal Findings The gene and protein expression of the H2S synthetase cystathionine-?-lyase (CSE) in the rat cochlea was examined using immunofluorescence and real-time PCR. Cochlear CSE mRNA levels varied according to the duration of noise exposure. A chronic intracochlear infusion model was built and artificial perilymph (AP), NaHS or DL-propargylglycine (PPG) were locally administered. Local sodium hydrosulfide (NaHS) significantly increased cochlear perfusion post-noise exposure. Cochlear morphological damage and hearing loss were alleviated in the NaHS group as measured by conventional auditory brainstem response (ABR), cochlear scanning electron microscope (SEM) and outer hair cell (OHC) count. The highest percentage of OHC loss occurred in the PPG group. Conclusions/Significance Our results suggest that H2S plays an important role in the regulation of cochlear blood flow and the protection against noise. Further studies may identify a new preventive and therapeutic perspective on NIHL and other blood supply-related inner ear diseases.

Hei, Ren-Yi; Zhang, Zhi-Bin; Wen, Li-Ting; Zhang, Peng-Zhi; Qiu, Jian-Hua; Qiao, Li

2011-01-01