Bioleaching of sulfide ores using non-metallic intensifying additives

A coupled study of sulphide mineralogy and chalcophile/ siderophile elements geochemistry (i.e., S, Se, Cu, As, V, Cd, Co, Zn, platinum-group elements and Au) has been undertaken in abyssal peridotites from the MARK area. The 28 samples analysed were mostly collected by submarine along the southern wall of the Kane transform fault. Compared to the peridotites drilled in the same area, our samples show a wide range of modal compositions (lherzolites, cpx-poor lherzolites and harzburgites) and of bulk-rock chemistry (1.5 1.85; SmN/YbN up to 1.4, N= chondrite normalized). Lherzolites and cpx-poor lherzolites show coarsergrained isolated cpx crystals in addition to the smaller cpx forming cpx+opx±sp clusters. These coarse-grained cpx are ascribed to in-situ precipitation of clinopyroxene from partial melts (Seyler et al., in prep.). Sulphides of indisputable magmatic origin have been observed in all of the peridotites. In spite of sea-water alteration and serpentinization, the number of magmatic sulphide grains positively correlates with fertility in the residual samples, decreasing from 1.2-3.7 grains/cm2 in the lherzolites to less than 0.5 grain/cm2 in the most refractory harzburgites. These latter still contain residual sulphides which provides further hypothesis of immiscible sulphide persisting in the mantle source of MORB-melts. Magmatic sulphides are closely associated with the small clusters-forming cpx crystals, being either enclosed or forming discrete grains adjacent to this silicate. In the weathered samples, magmatic sulphides are totally replaced by hydrous iron hydroxides (limonites) whereas the samples free from weathered products preserved sulfide assemblages typical of the reducing conditions generated by low T-serpentinization (i.e. Fe-rich pentlandite + magnetite ± mackinawite ± digenite ± troilite ± awaruite). Nevertheless, the peridotites refertilized by exotic MORB-type magmas display systematic sulphide enrichments (up to 5 grain/cm2) with respect to the sulphide vs. fertility correlation documented in the residual samples. Sulphides preferentially occur along or within the grain boundaries of the coarse-grained cpx. Similar sulphide enrichments have been observed in a few residual cpx-poor lherzolites devoid of melt/rock reaction evidence; however sulphides are disseminated within the serpentinized matrix at distance from the cpx. Clearly, several sulphide precipitation mechanisms operated in the oceanic mantle sampled by the Kane transform fault. The contents of moderately chalcophile elements (Cu, Zn, V, Co, Cd) and chalcogenides (S, Se, As) have been variably upgraded by sea-floor alterations. Weathered samples are systematically enriched compared to typical mantle compositions (up to 265 ppb Se; 200-400 ppm S with 2 occasional peaks at 2,000 ppm; up to 60 ppm As; up to 120 ppm Cu). None of the moderately chalcophiles positively correlates with the number of sulphide grains per polished thin sections and correlations with fertility indices are poor. By contrast, positive correlations such as Cu vs. Se, As vs. Se; Cu vs. As; Cd vs. Se and Zn vs. Cu suggest that these elements were contaminated by fluids from hydrothermal vents. However, apart from the weathered samples, S, Se as well as numerous moderately chalcophiles still show concentration ranges plotting on mantle melting trends. Some lherzolites display sub-chondritic S/Se ratios (~2,800) and Se and S contents that fit the range of oceanic mantle compositions recomputed from primitive MORBs (~200 ppm S; ~80 ppb Se). Gold contents (0.8-5 ppb) are almost systematically higher than mantle abundances, probably because of contaminations from hydrothermal vents. This element poorly correlates with indicators of melt depletion or magmatic sulphide precipitation. On the contrary, platinum-group elements were mostly insensitive to hydrothermal alterations, whether serpentinization or sea-floor weathering. Weathered and unweathered peridotites display PGE concentration ranges typical of mantle rocks (2-4 ppb Os, 2-4 ppb Ir; 4-8 ppb Ru; 0.7-1.4 ppb Rh; 3-9 ppb Pt; 0.2-8 ppb Pd). These concentration range are not affected by the alteration of magmatic sulphides into iron hydroxides. Strongly serpentinized harzburgites are the poorest in PGEs, perhaps because of the well-known diluting effect of serpentinization on trace elements. CI-chondrites normalized PGE patterns are similar to those reported for on-land unserpentinized mantle rocks, ranging from nearly flat to slightly fractionated. Compatible PGEs (Os, Ir, Ru and Rh) were not affected by partial melting or melt/rock reactions as their concentration ranges are uncorrelated with petrogenetic indicators of these processes. Os/Ir ratio is within the range of chondrites (0.9-1.2) whereas Ru/Ir and Rh/Ir are slightly higher than chondritic (1.7-2.3 and 0.3-0.4, respectively). Our sample provide further evidence that compatible PGEs are not extracted from the mantle as long as residual sulphides survive in partial melting residues. Pt Pd systematics are more variable. The most refractory harzburgites preserve negatively-trending chondrite normalized PGE patterns (0.7<PtN/IrN<1.1; 0.3<PdN/IrN<0.5). Even in S-saturated conditions, the most incompatible PGEs are more readily extracted than compatible PGEs from the oceanic mantle; however, Pt was less systematically fractionated than Pd. The lherzolites and cpx-poor lherzolites show Pt/Ir and Pd/Ir varying in a rather complex way, especially the cpx-poor lherzolites that show the largest scatter of PdN/IrN (0.2-2.2). The samples refertilized by exotic MORB-type melts have been enriched in all the PGE by sulphide precipitation. However, their PGE patterns are typical of residual mantle rocks (i.e. lower-than-chondritic PdN/IrN (0.2-1). Where sulphides precipitated during in-situ fractional crystallization of partial melts, the samples show suprachondritic PdN/IrN (1.6-2.0) and PtN/IrN (1-1.2). Their PGE patterns is complementary to those of the refractory harzburgites and their PGE contents do not correlate with sulphide modal abundance or in-situ precipitated coarse cpx crystals. As documented in other abyssal peridotites (Hess Deep (Leg 895), Kane fracture zone (Leg 920), .i.e. Rehkamper et al., 1998), PGE systematics of abyssal peridotites are not fully explained by considering these rocks as simple mantle melting residues. Complex melt/rock reaction processes and coupled sulphide precipitation are to be considered to explain the large scatter of Pd/Ir and Pt/Ir. Preliminary in situ LA-ICPMS data on sulphides suggest the same variability between each sulphide grain. However, segregation of immiscible sulphide liquids does not necessarily yield supra-chondritic Pd/Ir and Pt/Ir ratios. Incomplete sulphide-silicate equilibration as well as mechanical transport of sulphides by silicate melts have to be taken into account to interpret these ratios.

Accumulation of sulfides in the basement of southern Hunan Province, China: Implications for Pb–Zn mineralization related to reduced granitoids

The Angouran Zn (Pb) deposit, NW Iran: Evidence for a two stage, hypogene zinc sulfide–zinc carbonate mineralization

The location and distribution of metal sources for felsic-magma related ore deposits in continental and island arcs (porphyry Cu-Au-Mo, epithermal Au-Ag, and skarn) is contentious. Crustal and mantle sources may both contribute to the metal budgets of these types of deposits, with a chemical signature that is set early. Mixing between mantle-sourced magmas and crustal partial melts in Mixing, Assimilation, Storage, and Homogenisation (MASH) zones, at or near the base of the Earth’s crust, is a possible mechanism to generate fertile magmas for ore development. Magma mixing of this sort may have an important role in sulfur solubility and thus sulfide mineral stability. Sulfide minerals partition Cu, Au, Ag, Mo, platinum group elements, and other chalcophile metals, which are key components in felsic magma-related ore deposits. This study investigates the role of magma mixing in the production of sulfide melts in the lower crust and the role that these sulfide melts have in ore generation in the upper crust. Geochemical data from samples collected in the lower crustal Opirarukaomappu Gabbroic Complex (OGC), southeastern Hokkaido, Japan suggest that sulfide occurrences are associated with magma compositions produced by mixing ~80% gabbro with ~20% tonalite. High temperature, high pressure piston cylinder experiments are used to simulate this mixing and the consequent saturation and exsolution of sulfide melt. A new, redox-controlled, model for sulfide saturation, called the “sulfur fence”, describes a sudden reduction in sulfur solubility caused by the mixing of oxidised, sulfate-rich magmas with magmas containing a strongly reducing component (i.e. graphite). In this model, reduction from sulfate-stable to sulfide-stable decreases sulfur solubility by an order of magnitude (from ~1 wt. % to ~0.1 wt. %). Resulting large scale sulfur oversaturation may allow the generation of pervasive and voluminous sulfide melts in mixing magmas. The greater density of sulfide melts causes them to settle through lower density silicate magmas. Small globules (

Abundant upper mantle (peridotite and pyroxenite) xenoliths occur in Miocene basaltic diatreme pipes and Quaternary lava flows on the Hyblean Plateau (Sicily, Southern Italy). Peridotites are spinel-facies protogranular-textured harzburgites and lherzolites (Fo90, En89, Cr-diopside, Cr-rich spinel), that equilibrated at temperatures between 950 and 1050°C. Even the freshest Hyblean peridotites exhibit some serpentine content. Major-element distribution and abundance reflect depletion (high MgO, low Al2O3) related to one or more melt extraction events, but evidence of modal and cryptic metasomatism does exist. For instance, phlogopite of metasomatic origin occurs rarely in these peridotites. Geochemical evidences of metasomatism includes Light Rare Earth Element (LREE) (e.g. LaN/YbN = 9-19). Sr-Nd and He isotopic signatures are also consistent with the refertilization of the lithospheric peridotite matrix (full descriptions in Sapienza and Scribano, 2000, Sapienza et al., 2005 and references therein). To better define the metasomatic reservoir, we performed in situ Os isotope analyses on sulphides from mantle peridotite collected from Valle Guffari Miocene diatreme. Eight peridotite xenoliths were cut in blocks, stuck on thin section glasses and polished on one side. Sulfides were imaged using a Cameca SX-100 electron microprobe. Then, Os isotope analyses were performed using a Merchantek LUV266 nm laser ablation microprobe (LAM) attached to a Nu Plasma multi-collector ICP (MC-ICP). The laser spot size was ~60 mm. Only 4 peridotite samples contain measurable sulfides, resulting in 11 analyses. Analytical details are in Pearson et al. (2002). Sulfides in the Hyblean peridotites are Ni-rich, often Ferich, and enclose a Cu-rich phase (Fig. 1). Their shape is variable, from spheroidal to irregularly shaped, usually displaying curvilinear margins (Fig. 1). The grainsize ranges from tens to ~250 mm. Sulfides are mainly related to the serpentine network. A few sulfides are olivine-enclosed but are too small to be analysed. 187O/188Os ratios range from 0.110408 to 0.124398, which correspond to sub-chondritic values. 187Re/188Os ratios range from 0.0296463 to 1.41346, i.e. supra- to subchondritic values (Fig. 2). Five out of 6 sulfides from one sample (GE12) show similar 187Os/188Os but different 187Re/188Os, while the remaining sulfide and the other samples all align along an oblique array showing a negative correlation between 187Os/188Os and 187Re/188Os. Assuming the 187Re decay constant after Smoliar et al. (1996), 187Re/188Os- CHUR and 187Os/188OsCHUR after Walker and Morgan. (1989), we calculate Re-depletion ages (TRD) and model age (TMA). TRD represents the minimum melt-depletion age of the lithospheric mantle, since the calculation minimizes the effect of metasomatism-driven Re addition, while TMA assumes that the considered mantle portion remains in closedsystem conditions through time (Walker et al., 1989). Low- 187Os/188Os sulfides from peridotite GE12 show Paleoprotezoic to Archean TRD ages, while the other sulfides are Neoand Mesoproterozoic. TMA yields meaningless age (future or even older than the Earth’s formation), reflecting recent disturbance of the Re/Os ratio. GE12 sulfides show the same unradiogenic 187Os/188Os composition (except for one sulfide) but 187Re/188Os ranging from 0.8-1.4 (Fig. 2). This indicates that Os isotope composition does not depend on time-integrated in situ 187Re, but rather suggests the metasomatic effects with Re addition probably occurring shortly prior the eruption. The negative correlation between 187Os/188Os and 187Re/188Os in the other samples also supports the metasomatic origin of Re, and rather suggests mixing between two reservoirs with different Re-Os signatures (Wang et al., 2003; Fig. 2). Thus, the Hyblean peridotites we have studied experienced melt extraction event(s) – which would remove Re from the system - and underwent later metasomatic Re-enriching event(s). Although these preliminary Re-Os data - and the large associated uncertainties - on peridotite sulfides do not allow the calculation of a very detailed ages, TRD ages are realistic and require a Proterozoic-Archean minimum age for these portions of the Hyblean lithospheric mantle. Most sulfides in peridotite GE12 testify to recent Re addition, while the other peridotite sulfides and one GE12 sulfide seem to be the results of mixing between two metasomatic end-members. The low-187Os/188Os sulfides in sample GE12 may be representative of the low-187Os/188Os endmember. The occurrence of sulfides with different Os isotope signatures in sample GE12 confirms the importance of using in situ technique in such petrological study.

The Zn-Pb sulfide and Pb-Zn-Ag non-sulfide Kuh-e-Surmeh ore deposit, Zagros Belt, Iran: Geologic, mineralogical, geochemical, and S isotopic constraints

Nickel and Cobalt Ores: Flotation

Objective To investigate the effects of exogenous hydrogen sulfide on brain edema and injury and their mechanisms. Methods Sixty male SD rats were randomly divided into a sham operation group, an ischemia-reperfusion group, a 30 ppm hydrogen sulfide group, and a 60 ppm hydrogen sulfide group (n=15 in each group; 1 ppm=1 mg/L). A model of focal cerebral ischemia for 2 h and reperfusion for 24 h was induced by middle cerebral artery occlusion. The neurological scores were observed after 24 h cerebral ischemia-reperfusion. The cerebral infarction volume, the degree of brain edema, and the changes of blood-brain barrier permeability were measured. Western blotting was used to detect the expressions of occludin and zonula occludens-1 protein (ZO-1) in ischemic penumbra. Results Compared with the ischemia-reperfusion group, the neurological function scores in the 30 ppm and 60 ppm hydrogen sulfide group significantly increased in a dose-dependent manner (all P<0.05) and the neurological deficits and infarct volume reduced (all P<0.05), and the brain edema alleviated (all P<0.05). The content of Evans blue in the ischemic brain tissue in the ischemia-reperfusion group increased significantly compare with the sham operation group (0.74±0.14 μg/100 mg vs. 0.19±0.06 μg/100 mg; P<0.05). The content of Evans blue in the brain tissue in the 30 ppm hydrogen sulfide group (0.55±0.10 μg/100 mg) and the 60 ppm hydrogen sulfide group (0.35±0.08 μg/100 mg) decreased significantly compared with the ischemia-reperfusion group (all P<0.05), among them the 60 ppm hydrogen sulfide group was significantly lower than the 30 ppm hydrogen sulfide group (P<0.05). Western blot analysis showed that expression levels of occludin in penumbra (0.621%±0.101% vs. 0.787%±0.087% vs. 0.453%±0.127%; P<0.05) and ZO-1 (0.602%±0.118% vs. 0.778%±0.805% vs. 0.426%±0.146; P<0.05) in the 30 ppm and 60 ppm hydrogen sulfide groups increased significantly compared with the ischemia-reperfusion group, among them, the expression levels of occludin and ZO-1 in the 60 ppm hydrogen sulfide group were significantly higher than those in the 30 ppm hydrogen sulfide group (all P<0.05). Conclusions Inhalation of exogenous hydrogen sulfide can significantly attenuate brain edema after ischemia-reperfusion in a dose dependent manner, reduce infarct volume, and improve neurological function.Their mechanisms may be associated with inhibiting the downregulated expressions of occludin and ZO-1 and maintaining the integrity of the blood-brain barrier. Key words: Hydrogen Sulfide; Brain Ischemia; Reperfusion Injury; Brain Edema; Blood-Brain Barrier; Occludin; Zonula Occludens-1 Protein; Neuroprotective Agents; Rats

Sulphide ore is one of the most abundant minerals in nature. Indonesia has a very diverse potential for minerals, ranging from iron ore, laterite iron ore, iron sand to iron sulphide ore. Sulphide ore is one of the minerals that has the potential to become the parent mineral for gold. One area that has sulfide ore is Wanggameti Village, Matawai Lapawu District, East Sumba Regency. This condition encourages research to be carried out with the aim of knowing the types of minerals in sulfide ores by XRD analysis and to identify the content of elements in sulfide ores by XRF analysis. The results showed that the results of XRD analysis of sulfide ore samples taken from Wanggameti Village, Matawai Lapawu District, East Sumba Regency contained minerals of the types Quartz (SiO2), Calsite (CaCO3), Corundum (Al2O3), Iron Aluminum Silicon (Fe3Al2Si3) and Muscovite 2M1 ( KAl2Si3AlO10(OH)2). And the results of the analysis of the content of elements in the sulfide ore with XRF is 36.6% Si; S 1.2%; K 5.0%; Ca 27.8%; Ti 1.98%; V 0.23%; Cr 0.09%; Mn 0.77%; Fe 19.3%; Ni 2.99%; Cu 0.43%; Zn 0.1%; Mo 2.8%; Ba 0.2%; Eu 0.2% and Re 0.3%.&#x0D; Keywords:sulfide ore, mineral type and chemical composition

Biogenic Sulfur Emissions: A Review U.S. National Biogenic Sulfur Emissions Inventory Variability in Biogenic Sulfur Emissions from Florida Wetlands Synthesis and Emission of Hydrogen Sulfide by Higher Plants Sulfur Emissions from Roots of the Rain Forest Tree Stryphnodendron excelsum: Ecosystem, Community, and Physiological Implications Origin of Hydrogen Sulfide in Freshwater Sediments Sulfur Cycling in an Experimentally Acidified Seepage Lake Reactivity of Sulfur Nucleophiles Toward Halogenated Organic Compounds in Natural Waters The Distribution of Dimethyl Sulfide in the Oceans: A Review Biogeochemical Cycling of Dimethyl Sulfide in Marine Environments Dimethyl Sulfide Production in Marine Phytoplankton Dimethyl Sulfide and (Dimethylsulfonio)propionate in European Coastal and Shelf Waters Microbial Metabolism of Dimethyl Sulfide Metabolism of Acrylate and 3-Mercaptopropionate: Decomposition Products of (Dimethylsulfonio)propionate in Anoxic Marine Sediments Mechanistic Studies of Organosulfur (Thiol) Formation in Coastal Marine Sediments Reduced Sulfur Compounds in the Marine Environment: Analysis by High-Performance Liquid Chromatography Enzymatic Steps and Dissimilatory Sulfur Metabolism by Whole Cells of Anoxyphotobacteria Thermodynamics and Kinetics of Hydrogen Sulfide in Natural Waters Hydrogen Sulfides in Oxic Seawater Dimethyl Sulfide and Hydrogen Sulfide in Marine Air Distribution of Biogenic Sulfur Compounds in the Remote Southern Hemisphere Sulfur Isotope Ratios: Tracers of Non-Sea Salt Sulfate in the Remote Atmosphere Two Automated Methods for Measuring Trace Levels of Sulfur Dioxide Using Translation Reactions Gas-Phase Atmospheric Oxidation of Biogenic Sulfur Compounds: A Review OH-Initiated Oxidation of Biogenic Sulfur Compounds: Kinetics and Mechanisms Under Atmospheric Conditions Mechanism of Atmospheric Oxidation of Sulfur Dioxide by Hydroxyl Radicals Mechanisms for the Reaction of CH[3S with NO[2 The Impact of Halogen Oxides on Dimethyl Sulfide Oxidation in the Marine Atmosphere Fourier Transform IR Studies of the Reactions of Dimethyl Sulfoxide with OH, NO[3, and Cl Radicals North Sea Dimethyl Sulfide Emissions as a Source of Background Sulfate over Scandinavia: A Model The Uptake of Gases by Liquid Droplets: Sulfur Dioxide Rate of Reaction of Methanesulfonic Acid, Dimethyl Sulfoxide, and Dimethyl Sulfone with Hydroxyl Radical in Aqueous Solution Oxidation of Biogenic Sulfur Compounds in Aqueous Media: Kinetics and Environmental Implications

Origin of the Tudun Cu–Ni sulfide deposit in the eastern Tianshan, NW China: Constraints on the geochemistry of platinum group elements

The Huogeqi orefield located on the northern side of Mt. Langshan, Inner Mongolia occurs in the Middle Proterozoic Langshan Group metamorphic rocks, and the orebodies are stratiform. In the past twenty years, many Chinese geologists have conducted researches on the Huogeqi Cu-Pb-Zn deposit, but there has been still a controversy on its origin. Some advocate that the deposit is of sedimentary-metamorphic reworking origin, some hold that it is of sea-floor SEDEX origin, and others have a preference for magmatic superimposition origin. The crux of the controversy is that there is no common understanding about the source of ore-forming materials. In this paper, the Pb isotopic compositions of regional Achaean-Early Proterozoic basement rocks, various types of sedimentary-metamorphic rocks and volcanic rocks in the mining district, Late Proterozoic and Hercynian magmatic rocks are introduced and compared with the ore-lead composition, so as to constrain the source of the ore lead. The result indicates that (1) sulfides in the ores have homogeneous Pb isotopic compositions, showing a narrow variation range. Their 206Pb/204Pb ratios are within a range of 17.027–17.317; 207Pb/204Pb ratios, 15.451–15.786 and 208Pb/204Pb ratios, 36.747–37.669; (2) the Pb isotopic compositions of the regional Achaean-Early Proterozoic basement rocks are characteristic of the old Pb isotopic composition at the early-stage evolution of the Earth, which varies over a wider range, reflecting significant differences in Pb isotopic compositions of the ores. All this indicates that the source of ore lead has no bearing on the basement rocks; (3) the sedimentary-metamorphic rocks in the mining district are characterized by highly variable and more radiogenic Pb isotopic compositions and their Pb isotopic ratios are obviously higher than those of ores, demonstrating that ore lead did not result from metamorphic reworking of these rocks; (4) Pb isotopic compositions of Late Proterozoic diorite-gabbro and Hercynian granite are higher than those of ores. Meanwhile, the Pb isotopic compositions of sulfides in the small-sized strata-penetrating mineralized veinlets formed at later stages are completely consistent with that of sulfides in stratiform-banded ores, suggesting that these veinlets are the product of autochthonous reworking of the stratiform-banded ores during the period of metamorphism and the late magmatic superimposition-mineralization can be excluded; (5) amphibolite, whose protolith is basic volcanic rocks, has the same Pb isotopic compositions as ores, implying that ore lead was derived probably from basic volcanism. So, the source of ore-forming materials for the Huogeqi deposit is like that of the volcanic massive sulfide (VMS) deposits. However, the orebodies do not occur directly within the volcanic rocks, and instead they overlie the volcanic rocks, showing some differences from those typical VMS-type deposits.

As the third confirmed gaseous transmitters, hydrogen sulfide was found to play a vital role in the eternal milieu both physiologically and pathologically. What's intriguing is that, there exists a debate about the role of hydrogen sulfide in the pathogenesis of cancer, especially colorectal cancer. In this manuscript, progress of the effect of low and high dose hydrogen sulfide on the tumorigenesis of colorectal cancer and research on the antitumor new drugs stemmed from the function of hydrogen sulfide is summarized. Recently, the "bell-shape" model of the action of hydrogen sulfide illustrated that hydrogen sulfide was able to promote the progression of tumor in low dose and inhibit the progression of tumor in high dose. Based on these results, both hydrogen sulfide synthesis inhibitors and hydrogen sulfide donors(chimeras with NSAIDs) have been widely studied as potential anti-tumor novel drugs. According to the actual results of present studies, hydrogen sulfide synthesis inhibitors featured by aminooxyacetic acid (AOA) is more promising as a novel kind of drug. The future research based on the relationship between hydrogen sulfide and rectal cancer may bring insights into the development of novel anti-tumor drugs, thus producing tremendous potential clinical value.

Denitrification is a critical step in biological wastewater treatment process since nitrogen reduction is easily affected by various conditions. The complicated compositions in the wastewater (such as types of carbon source, sulfide concentration) and reaction conditions (e.g. temperature, pH, dissolved oxygen) affect efficiency and pathways of the denitrifying microbial dissimilation. Previous studies are not shown clear statements on related mechanisms and constrains. As a result, this study performed a modified denitrfication process, namely simultaneous denitrification and sulfide degradation (SDSD), via one unique denitrfier, Pseudomonas sp. C27. This heterotrophic species was isolated from an expanded granular sludge bed (EGSB) reactor and is reported more efficient than autotrophic species. Experiments are carried out in a tailor-made continuous-flow stirred reactor (CSTR). Composition of feed, i.e. various carbon sources (including alcohol, organic acid and carbonhydrate), and initial sulfide concentration (0, 50, 96.1, 193.5, 302.1 and 404.6 mg.L-1), are prepared in the lab and tested SDSD efficiency. In the meanwhile, effects of operational conditions, pH (6.5, 7.0, 8.5, 9.0, 9.5, 10.15 and 11) and temperature (20, 25, 30, 35, 40, 45℃), on SDSD efficiency are investigated. Results are shown that the optimum conditions for this strain to achieve SDSD are at 25~30℃ and pH 9~9.5. The most easy assimilated carbon source for Pseudomonas sp. C27 is acetate although other smaller molecular organics (such as succinate and malate) can be biodegraded within 24 hours. The sulfide and acetate were used as electron donors, and the end product of sulfide oxidation was sulfur or thiosulfate by the NO3-N/S2—S molar ratios. Moreover, products of nitrate reduction were determined by the initial sulfide concentrations, when the initial sulfide concentrations were set below 96.1mg/L, the nitrate was conveted to nitrogen gas; Moreover, the sulfide concentration reached 193.5mg/L, the nitrite reductase was strongly inhibited by sulfide casuing the main end product of denitrification was nitrite. When the sulfide concentration was as high as 302.1mg/L, the isolate C27 didn’t display growth and the ability of denitrification. In micro-oxygen condition (DO=0~10%) the growth time of bacterium was shorted 48 hours compare with anaerobic condition, because of the specify activity of enzymes were higher than anaerobic condition. Testing in a CSTR at sustainable loadings of 0.215 kg m-3day-1 for sulfide, 0.146 kg m-3day-1 for nitrate-nitrogen , 0.092 kg m-3day-1 for acetate-carbon with 84.7%, 99.5%, 74.1% efficiency respectively. Mass balance of sulfur are calculated to facilitate analyzing microbial preferred reactions and possible SDSD pathways for Pseudomonas sp. C27 are suggested in the end of this thesis.

Objective To detect the change of the plasma hydrogen sulfide in patients with chronic heart failure (CHF) and explore its clinical significance.Methods A total of 118 patients with CHF was enrolled in this study.According to the NYHA standard,they were classified into grade Ⅱ (34 cases),grade Ⅲ (54 cases),grade Ⅳ (30 cases).The patients were divided into normal treatment group and sodium nitroprusside treatment group with 59 cases each.Another 30 healthy person were selected as control group.The plasma hydrogen sulfide level was detected by spectrophotometer.Results The plasma hydrogen sulfide level in CHF patients and healthy person was (32.45 ± 3.86),(54.26 ± 5.63) μ mol/L,and there was significant difference (P ＜ 0.05).The plasma hydrogen sulfide level in CHF patients of grade Ⅱ,Ⅲ,Ⅳwas (43.26 ±4.73),(31.87 ±4.12),(23.66 ±3.54) μmol/L,and there was significant difference (P＜0.05).The plasma hydrogen sulfide level before treatment in normal treatment group and sodium nitroprusside treatment group was(31.66 ± 3.75),(33.04 ± 4.02) μ mol/L,and there was no significant difference between two groups (P ＞ 0.05).The plasma hydrogen sulfide level after treatment in normal treatment group and sodium nitroprusside treatment group was (36.83 ± 4.32),(44.54 ± 4.68) μ tmol/L,and there was significant difference (P ＜0.05).The plasma hydrogen sulfide level after treatment in two groups was increased compared with that before treatment,and there was significant difference (P ＜ 0.05).The total effective rate in normal treatment group and sodium nitroprusside treatment group was 42.4％ (25/59) and 67.8％(40/59),and there was significant difference between two groups (P ＜ 0.05).Conclusions The abnormal plasma hydrogen sulfide level may be involved in the occurrence and development process of CHF,which could be used as a factor to monitor the disease.The upregulation of plasma hydrogen sulfide level can significantly improve the prognosis of CHF patients. Key words: Heart failure; Hydrogen sulfide; Sodium nitroprusside