Water Sulfide Research Articles

New perspective to Keplerate polyoxomolybdates: Green oxidation of sulfides with hydrogen peroxide in water

The catalytic activity of three Keplerate polyoxometalates Mo72M30 (M=V, Cr, Fe) was examined in the H2O2-based oxidation of different sulfides in water. Various sulfides were successfully converted into the corresponding sulfones under mild reaction conditions with high to excellent yields. The recyclability of Keplerate POM catalysts did not show a significant loss of catalytic activity up to five times. The use of water and hydrogen peroxide as green solvent and oxidant makes these reactions interesting from environmental and economic points of view.

A new analytical approach to determining Mo and Re speciation in sulfidic waters

The distinct reactivities of Mo and Re in oxic versus anoxic waters make these elements ideally suited for use as redox proxies. However, their full exploitation as geochemical tracers requires that their chemical transformations in sulfidic water be well understood. While thermodynamic data have been used to predict Mo and Re speciation within sulfidic waters, these predictions remain unsubstantiated because effective methodologies for separating the thiomolybdate (MoVIOxS4−x2−) and thioperrhenate (ReVIIOxS4−x−) anions within natural settings have yet to be developed. Anion exchange chromatography (AEC) is often employed to provide separation of environmentally important anions. For example, thiometalates of As and Sb have been quantified in sulfidic geothermal waters using AEC coupled with inductively coupled plasma mass spectrometry (ICP-MS). Unfortunately, AEC methods are incapable of separating the thiomolybdate or thioperrhenate anions due to the extreme retention these thiometalates experience on AEC columns. Because reverse phase ion pair chromatography (RP-IPC) offers greatly diminished retention times, we have developed RP-IPC methods that are capable of separating all stable thiomolybdates and thioperrhenates within 40min. An isocratic method provides effective separation of the thiomolybdates. Thioperrhenates and mixtures of the thiomolybdates and thioperrhenates require gradient methods. Addition of p-cyanophenol (p-CP) to the eluent markedly reduces thiometalate retention and facilitates their separation. Our efforts could lead in the near future to coupling RP-IPC with ICP-MS or multi-collector ICP-MS for characterizing Mo and Re speciation in natural sulfidic waters as well as potential fractionation among Mo and Re isotopes during speciation changes.

AN OVERVIEW ON DISTRIBUTION AND ABUNDANCE OF MEIOBENTHIC FORAMINIFERA IN THE BLACK SEA

A research program to study Black Sea meiobenthos yielded extensive data on foraminifera with either a soft or a hard shell. Samples were taken in different parts of the Sea, ranging from shallow bays to the layer of constant hypoxia over-lying sulphidic waters. A review of new information on the species composition of single-chambered foraminifera (i.e. monothalamids, sometimes termed ‘allogromiids’) is presented. The data on the ratio of the number of soft-shelled monothalamids and multi-chambered hard-shelled foraminifera in shallow water on the shelf and in the layer of permanent hypoxia are given. It is shown that in many habitats the number of single-chambered species is higher than total number of multi-chambered taxa. Monothalamids are more resistant to hypoxia, they are found closer to the boundary of sulfidic waters, and they occupy deeper sediment layers.

Hexametaphosphate-Capped Silica Mesoporous Nanoparticles Containing Cu(II) Complexes for the Selective and Sensitive Optical Detection of Hydrogen Sulfide in Water.

Cu(II) -macrocycle functionalized hexametaphosphate-capped silica mesoporous nanoparticles have been prepared and used for the selective and sensitive detection of hydrogen sulfide in aqueous environments. The possibility of using different metal complexes combined with different capping anions and choice of different dyes or other sensing molecules as indicators makes this new protocol highly appealing for the preparation of new sensing systems for sulfide detection in different environments.

Sulfide Oxidation by a Noncanonical Pathway in Red Blood Cells Generates Thiosulfate and Polysulfides

A cardioprotectant at low concentrations, H2S is a toxin at high concentrations and inhibits cytochrome c oxidase. A conundrum in H2S homeostasis is its fate in red blood cells (RBCs), which produce H2S but lack the canonical mitochondrial sulfide oxidation pathway for its clearance. The sheer abundance of RBCs in circulation enhances the metabolic significance of their clearance strategy for H2S, necessary to avoid systemic toxicity. In this study, we demonstrate that H2S generation by RBCs is catalyzed by mercaptopyruvate sulfurtransferase. Furthermore, we have discovered the locus of sulfide oxidation in RBCs and describe a new role for an old protein, hemoglobin, which in the ferric or methemoglobin state binds H2S and oxidizes it to a mixture of thiosulfate and hydropolysulfides. Our study reveals a previously undescribed route for the biogenesis of hydropolysulfides, which are increasingly considered important for H2S-based signaling, but their origin in mammalian cells is unknown. An NADPH/flavoprotein oxidoreductase system restores polysulfide-carrying hemoglobin derivatives to ferrous hemoglobin, thus completing the methemoglobin-dependent sulfide oxidation cycle. Methemoglobin-dependent sulfide oxidation in mammals is complex and has similarities to chemistry reported for the dissolution of iron oxides in sulfidic waters and during bioleaching of metal sulfides. The catalytic oxidation of H2S by hemoglobin explains how RBCs maintain low steady-state H2S levels in circulation, and suggests that additional hemeproteins might be involved in sulfide homeostasis in other tissues.

Oxidation process of dissolvable sulfide by synthesized todorokite in aqueous systems

Todorokite, formed from Mn(II) in supergene environments, can affect the transformation and migration of dissolvable sulfides in soils and water. In this work, todorokite was synthesized with different degrees of crystallinity, and the redox mechanism of dissolvable sulfide and todorokite was studied in both closed and open aqueous systems. The influences of pH, temperature, crystallinity, the amount of manganese oxides, and oxygen gas on S2− oxidation process were investigated. It is found that S2− was oxidized to S0, SO32−, S2O32− and SO42−, and about 90% of S2− was converted into S0 in closed systems. The participation of oxygen facilitated the further oxidation of S0 to S2O32−. S0 and S2O32− were formed with the conversion rates of S2− about 45.3% and 38.4% after 1h of reaction, respectively, and the conversion rate for S2O32− increased as reaction prolonged for a longer period. In addition, todorokite was reduced to Mn(OH)2 in the presence of nitrogen gas, and its chemical stability increased when oxygen gas was admitted into the reaction system during the process. The oxidation rate of dissolvable sulfide followed a pseudo-first-order kinetic law in the initial stage (within 10min), and the initial oxidation rate constant of S2− increased with elevating temperature, increasing the quantity and decreasing crystallinity of todorokite. The initial oxidation rate of dissolvable sulfide decreased with continuous feeding of O2 into the test solution, possibly due to a decrease in active Mn(III) content in todorokite. The present work demonstrates the redox behaviors and kinetics of dissolvable sulfide and todorokite in aquatic environments.

The balneotherapeutic components of sulfide-containing mineral waters

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

Assessment of the physical environment of epigean invertebrates in a unique habitat: the case of a karst sulfidic spring, Slovenia

AbstractA well‐fissured and faulted karst area at the Žveplenica sulfidic spring created suitable conditions for epigean copepods. Their presence in sulfidic water is a rare phenomenon. To understand the conditions related to sulfidic habitats in the region, two additional springs were analysed: the Studenec karst spring and the Sovra artesian borehole, which contains dissolved sulfide. Water temperature, chemistry and the stable isotopes of oxygen and hydrogen show that the Sovra borehole water has a different origin and history to that of the Žveplenica and Studenec springs water, which is derived from local precipitation. The low slope of the δ18O–δ2H regression line for the Žveplenica spring indicates a mixing of local precipitation water with geothermal sulfidic water that may explain the presence of live copepods. These harpacticoid and cyclopoid copepods must have survived anoxia and high sulfide for some time. The mean transit time for Žveplenica spring cannot be defined precisely from the available data, although the degree of attenuation of the isotopic signal indicates mean transit times of about 1·0 to 1·5 years. Sites similar to Žveplenica spring should be carefully analysed because not only do they provide insights into biodiversity but they also represent an ecotone between the anoxic/oxic and high/low sulfide of these karst waters. Copepods in similar geological settings can be used as additional parameters to evaluate conditions in subsurface sulfidic habitats and their spatial connectivity and responses to hydrological events. Copyright © 2014 John Wiley & Sons, Ltd.

Hydrate Phase Equilibria of Gaseous Mixtures of Methane + Carbon Dioxide + Hydrogen Sulfide

In this communication, we report experimental dissociation conditions for clathrate hydrates of methane + carbon dioxide + hydrogen sulfide in liquid water—hydrate-vapor equilibrium. The dissociation temperatures and pressures are in the ranges of 273.9–288.25 K and 0.316–1.94 MPa, respectively. Concentrations of methane, carbon dioxide, and hydrogen sulfide in the feed gas also varied. To perform the measurements, an isochoric pressure-search method was used. The dissociation data obtained in the present work are compared with the predictions of a thermodynamic model (HWHYD version 1.1). A discussion on the deviations between the experimental and predicted data is made. It is argued that the model parameters should be re-adjusted for the systems containing carbon dioxide and hydrogen sulfide.

A pilot study on remediation of sediments enriched by oyster farming wastes using granulated coal ash

In order to evaluate the ability of granulated coal ash (GCA), a byproduct of coal thermal electric power stations, to remove hydrogen sulfide from organically enriched sediments, a pilot study was carried out at oyster farming sites, where sediments were enriched with oyster feces and dead oysters. Concentration of hydrogen sulfide in the interstitial water of the sediment decreased to nearly zero in both experimental sites, whereas it remained over 0.2mg/l in the control site. Concentration of acid volatile sulfide (AVS) in the sediment also decreased significantly in both experimental sites, while remained over 0.4mg/g in the control site. Increases were observed in both the number of benthic microalgae species and the individual number of benthic animals in the surface sediments. This may have been due to the decrease in hydrogen sulfide.

Use of some methods in the removal of hydrogen sulfide from sulfide water and used it for irrigation of barley crop

Laboratory experiment was carried out in the laboratories of the college of Agriculture, University of Anbar to study the properties of sulfide water and processing methods for the disposal of hydrogen sulfide, which is toxic to humans, animals and plants alike. A treatments using were aeration, activated carbon, bentonite clay, nitric acid, hydrogen peroxide and manganese oxide, has been compared to the results of the processors in terms of rates of removal of hydrogen sulfide. The field experiment of the barley crop irrigated with water treated in various methods and untreated sulfide water compared with of the Euphrates River water and drainage water with electrical conductivity equal to the electrical conductivity of untreated sulfide water. The results showed that the best treatment for the removal of hydrogen sulfide are using nitric acid by removing 88%, followed by hydrogen peroxide treatment, removal by 77% and the least of which is the removal of treatment and ventilation by removing 40%. The results showed that more methods reduction of potential salinity was nitric acid is then followed by ventilation. All methods treatment led to an increase in dry weight and grain yield of barley crop compared with the weight of untreated sulfide water, but the increase was not significant for the treatment of bentonite and activated carbon while there is a significant increase for nitric acid, hydrogen peroxide and chlorine treatments

Significance of archaeal nitrification in hypoxic waters of the Baltic Sea.

Ammonia-oxidizing archaea (AOA) of the phylum Thaumarchaeota are widespread, and their abundance in many terrestrial and aquatic ecosystems suggests a prominent role in nitrification. AOA also occur in high numbers in oxygen-deficient marine environments, such as the pelagic redox gradients of the central Baltic Sea; however, data on archaeal nitrification rates are scarce and little is known about the factors, for example sulfide, that regulate nitrification in this system. In the present work, we assessed the contribution of AOA to ammonia oxidation rates in Baltic deep basins and elucidated the impact of sulfide on this process. Rate measurements with (15)N-labeled ammonium, CO(2) dark fixation measurements and quantification of AOA by catalyzed reporter deposition-fluorescence in situ hybridization revealed that among the three investigated sites the highest potential nitrification rates (122-884 nmol l(-1)per day) were measured within gradients of decreasing oxygen, where thaumarchaeotal abundance was maximal (2.5-6.9 × 10(5) cells per ml) and CO(2) fixation elevated. In the presence of the archaeal-specific inhibitor GC(7), nitrification was reduced by 86-100%, confirming the assumed dominance of AOA in this process. In samples spiked with sulfide at concentrations similar to those of in situ conditions, nitrification activity was inhibited but persisted at reduced rates. This result together with the substantial nitrification potential detected in sulfidic waters suggests the tolerance of AOA to periodic mixing of anoxic and sulfidic waters. It begs the question of whether the globally distributed Thaumarchaeota respond similarly in other stratified water columns or whether the observed robustness against sulfide is a specific feature of the thaumarchaeotal subcluster present in the Baltic Deeps.

Sulfate reduction and sulfide oxidation in extremely steep salinity gradients formed by freshwater springs emerging into the Dead Sea.

Abundant microbial mats, recently discovered in underwater freshwater springs in the hypersaline Dead Sea, are mostly dominated by sulfur-oxidizing bacteria. We investigated the source of sulfide and the activity of these communities. Isotopic analysis of sulfide and sulfate in the spring water showed a fractionation of 39-50‰ indicative of active sulfate reduction. Sulfate reduction rates (SRR) in the spring sediment (< 2.8 nmol cm(-3) day(-1)) are too low to account for the measured sulfide flux. Thus, sulfide from the springs, locally reduced salinity and O2 from the Dead Sea water are responsible for the abundant microbial biomass around the springs. The springs flow is highly variable and accordingly the local salinities. We speculate that the development of microbial mats dominated by either Sulfurimonas/Sulfurovum-like or Thiobacillus/Acidithiobacillus-like sulfide-oxidizing bacteria, results from different mean salinities in the microenvironment of the mats. SRR of up to 10 nmol cm(-3) day(-1) detected in the Dead Sea sediment are surprisingly higher than in the less saline springs. While this shows the presence of an extremely halophilic sulfate-reducing bacteria community in the Dead Sea sediments, it also suggests that extensive salinity fluctuations limit these communities in the springs due to increased energetic demands for osmoregulation.

Transformation of monothioarsenate by haloalkaliphilic, anoxygenic photosynthetic purple sulfur bacteria.

Thioarsenates are the dominant arsenic species in arsenic-rich, alkaline, and sulfidic waters, but bacterial interactions with these compounds have only recently been examined. Previous studies have shown that microorganisms play a role in the transformation of monothioarsenate to arsenate, including use of monothioarsenate as a chemolithotrophic electron donor coupled with oxygen as an electron acceptor. We obtained enrichment cultures from two saline, alkaline lakes (Mono Lake, CA and Big Soda Lake, NV) that are able to use monothioarsenate as the sole electron donor for anoxygenic photosynthesis. These anoxic cultures were able to convert a 1 mM mixture of thioarsenates completely to arsenate in c. 13 days and 4 mM monothioarsenate to arsenate in c. 17 days. This conversion was light dependent; thus, monothioarsenate can be used as the sole electron donor for anoxygenic photosynthesis. Both of the Mono Lake and Big Soda Lake enrichment cultures were dominated by an organism closely related to Ectothiorhodospira species. We tested additional strains of purple sulfur bacteria and found widespread ability to use monothioarsenate as an electron donor. The ability of bacteria to transform thioarsenates directly via anoxygenic photosynthesis adds a new perspective to the well-studied arsenic and sulfur cycles.

Tungsten speciation in sulfidic waters: Determination of thiotungstate formation constants and modeling their distribution in natural waters

Using UV/VIS spectrophotometry the equilibrium constants for the formation of monothiotungstate, WO3S2− (WO42-+H2S↔WO3S2-+H2O; log K01=3.08±0.11), dithiotungstate, WO2S22− (WO3S2-+H2S↔WO2S22-+H2O; log K12=3.22±0.22), trithiotungstate, WOS32− (WO2S22-+H2S↔WO3S2-+H2O; log K23=2.76±0.10), and tetrathiotungstate, WS42− (WO3S2-+H2S↔WS42-+H2O; log K34 ∼2.36) were determined. The equilibrium constants describing the formation of thiotungstates are approximately two orders of magnitude less than the equilibrium constants for the formation of the analogous thiomolybdates. These equilibrium constants for thiotungstates were used to model tungstate speciation in sulfidic waters. The model predicts that thiotungstate species are negligible in most natural waters, but are likely to be important in circum-neutral, anoxic waters with ⩾0.1mM S(-II) concentrations. Natural waters that are conducive to thiotungstate formation include the Black Sea, Tyro and Bannock Basins, and porewaters with high rates of sulfate reduction such as those common in salt marshes. Preliminary field investigations indicate that thiotungstate formation may lead to increased W solubility.

Occurrence of Polychlorinated Diphenyl Sulfides (PCDPSs) in Surface Sediments and Surface Water from the Nanjing Section of the Yangtze River

Polychlorinated diphenyl sulfides (PCDPSs) are dioxin-like compounds that could induce various adverse effects to organisms. However, little is known about the occurrence of PCDPSs in the riverine environment. In the present study, the concentrations of twenty-one types of PCDPSs in the surface sediments and in surface water from the Nanjing section of the Yangtze River were examined. A total of 19 types of PCDPSs were detected and ∑PCDPSs concentrations in surface sediment and surface water ranged from 0.10 to 6.90 ng/g and 0.18 to 2.03 ng/L, respectively. The 2,2',4,4',5-penta-CDPS was the dominant congener in sediment (19.9%) and 2,2',3,3'-tetra-CDPS was the most abundant congener in water (12.2%). The tetra-CDPSs were the dominant congeners both in sediment and in water. Compared with sediment, the percentage of lower chlorinated PCDPSs in water increased distinctly. Source analysis revealed that the PCDPSs in the sediment and in the water mainly came from chemical wastewater rather than domestic sewage. There was a significant linear correlation between ∑PCDPS concentrations and sediment TOC contents, while no linear correlation existed between ∑PCDPS concentrations and water DOC contents. This study demonstrated the prevalent contamination by PCDPSs in sediments and in water from the Nanjing section of the Yangtze River.

Morphological and molecular approaches reveal highly stratified protist communities along Baltic Sea pelagic redox gradients

The deep basins of the central Baltic Sea are characterized by anoxic and sulfidic bottom water and steep vertical pelagic redox gradients. The highly active prokaryotic assem- blages of this and other redox transition zones have been intensely studied, while knowledge on the protistan communities remains fragmentary. Thus, we conducted a multi-annual microscopy- based study, combined in one year with 18S rRNA gene and transcript-based DGGE fingerprints to identify the dominant protist taxa and to assess their vertical distribution. Both approaches, applied in high vertical resolution, demonstrated strong stratifications of the protist community composition along the redox gradient. The suboxic zone was dominated by dinoflagellates and oligotrichous ciliates related to Strombidium, whereas the interface and upper sulfidic zone were dominated by ciliates of the genera Mesodinium and Metacystis. Several flagellate taxa within the jakobids, euglenozoans and choanoflagellates occurred exclusively in sulfidic water. Our morpho- logical approach indicates that the pelagic redoxclines of the central Baltic Sea are inhabited by a stable and characteristic protist community. Incongruously, certain taxa (e.g. Mesodinium and Metacystis sp.) which remained undetected by the molecular fingerprinting technique could be identified and enumerated by microscopic observations, whereas small and virtually amorphous protists (especially flagellates) were detected only by sequencing DGGE bands. Fine-scaled assessment of dominant protists in distinct redox strata is a crucial step in understanding their impact and interactions with the prokaryotic world and the biogeochemical processes they medi- ate in these zones.

Highly selective relay recognition of hydrogen sulfide and Hg(II) by a commercially available fluorescent chemosensor and its application in bioimaging

A simple fluorescent probe, perylene-3,4,9,10-tetracarboxylic dianhydride, which is a commercially available organic pigment intermediate was reported as a fluorescence chemosensor for Hg(II). This probe can high selectively recognize hydrogen sulfide in water:DMSO (1:1 (v/v), 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) buffer, pH 7.4) solutions. Namely, with addition of various anions, only HS− can induce a turn on green fluorescence. The mechanism is that perylene-3,4,9,10-tetracarboxylic dianhydride was hydrolyzed and subsequently displaced when meeting with hydrogen sulfide. More interestingly, probe–hydrogen sulfide can successively detect Hg2+. The detection mechanism was based on Hg2+ snatching up sulfur group of probe–HS− adduct, which makes the probe regenerative. And their reaction products were proved by ESI-MS. Their potential application in bioimaging was also illustrated.

Kinetics and mechanism of the reaction of hydrogen sulfide with diaquacobinamide in aqueous solution.

We conducted a detailed kinetic study of the reaction of the vitamin B12 analog diaquacobinamide ((H2O)2Cbi(III)) with hydrogen sulfide in water from pH 3 to 11. The reaction proceeds in three steps: (i) formation of three different complexes between cobinamide and hydrogen sulfide, viz. (HO-)(HS-)Cbi(III), (H2O)(HS-)Cbi(III), and (HS-)2Cbi(III); (ii) inner-sphere electron transfer (ISET) in the two complexes with one coordinated HS- to form the reduced cobinamide complex [(H)S]Cbi(II); and (iii) addition of a second molecule of hydrogen sulfide to the reduced cobinamide. ISET does not proceed in the (HS-)2Cbi(III) complex. The final products of the reaction between cobinamide and hydrogen sulfide were found to be independent of pH, with the main product being a complex of cobinamide(II) with the anion-radical SSH2-.

Problems of Mechanized Tunneling In Gassy Ground Conditions a Case Study: Nousoud Water Transmission Tunnel

Current advances in science, followed by development of excavation equipments technology resulted in growth of tunnelling projects for different purposes. In spite of conducting exploratory studies prior to these projects, in some cases due to of impassable paths, the studies are limited to certain areas. Hence, during geotechnical studies, it is possible that all problems facing tunnelling not be detected. Therefore, lack of awareness of these conditions can result in a lack of proper planning and consequently lead to problems during the projects. Due to the lack of knowledge and consequently not predicting and planning the projects, drilling of the second sector of Nousoud water transmission tunnel, -26 km long- has been faced with many problems including emission of hydrogen sulfide and methane gas and drainage of high volumes of water containing dissolved gas into the tunnel, which has led to the loss of life, loss of working efficiency, as well as increased project costs. In this study, problems occurred in this project, reasons behind them will be addressed; and the solutions to these problems will be mentioned. The results of the study have shown that oil-bearing formations of the region and the immigration of gases coming from these formations have let the gas entered into the tunnel. In addition, due to the high solubility of hydrogen sulfide and methane gas in water on one hand, and hydrated formations with high permeability on the other hand, caused the influx of large quantities of water and therefore the concentration of these gases in the tunnel.