Aqueous sulfide

Sulfur Compounds. Aqueous sulfide and H2S, an odiferous compound in some waters, are oxidized rapidly (initially to sulfite and sulfurous acid) the rate constants ate 3x10 and 3 X 10 , respectively. Thiocyanate is oxidized by ozone to cyanide and sulfate via the intermediate formation of sulfite (47). 

Gillespie RJ, Passmore J (1971) Polycations of Group VI. Acc Chem Res 4 413 19 Giggenbach WF (1974) Equilibria involving polysulfide ions in aqueous sulfide solutions up to 240 °C. Inorg Chem 13 1724-1730... 

The kinetics and mechanism of the growth of anodic silver sulfide films on silver metal in aqueous sulfide solutions has been studied under potentiodynamic conditions [162], The Ag2S film formation was presumed to proceed as... 

In their pioneering work on the formation of photoelectrochemically active metal sulfides by oxidation of the parent metal electrode. Miller and Heller [29] reported the anodic formation of polycrystalline Bi2S3 on a bismuth metal electrode in a sodium polysulfide cell, wherein this electrode was used in situ as photoanode. When a Bi metal electrode is anodized in aqueous sulfide solutions a surface film is formed by the reaction... 

Birss VI, Wright GA (1982) The potentiodynamic formation and reduction of a silver sulfide monolayer on a silver electrode in aqueous sulfide solutions. Electrochim Acta 27 1-7... 

In situ metallization has been claimed to provide a convenient method for the preparation of metal-deposited and metal sulfide deposited CdS during photocatalytic decomposition of aqueous sulfide. As-prepared MS/CdS and M/CdS bifunctional photocatalysts (MS = Pt or Ir sulfide M = Pt or Ir) were reported to be more active photocatalysts than CdS and ex-situ metallized CdS [285]. 

Rufus IB, Viswanathan B, Ramakrishnan V, Kuriacose JC (1995) Cadmium sulfide with iridium sulfide and platinum sulfide deposits as a photocatalyst for the decomposition of aqueous sulfide. J Photochem Photobiol A 91 63-66... 

Shenberger, D.M. (1986) Gold solubility in aqueous sulfide solutions. Unpub. Masters Thesis, Pennsylvania... 

Kobayakawa, K., Miura, T., Suzuki, A., Sato, Y., and Fujishima, A., Enhancement of the photocatalytic activity of CdS powder for hydrogen evolution from aqueous sulfide solution by heat treatment with KC1, Solar Energ. Mater. Solar Cells, 30, 201,1993. 

To set up the simulation, we use the thermodynamic dataset from the calculation in Section 18.5, which was expanded to include mackinawite (FeS). As before, we suppress the iron sulfide minerals pyrite and troilite, and decouple acetate and methane from carbonate, and sulfide from sulfate. We set the aquifer to include a small amount of siderite, which serves as a sink for aqueous sulfide,... 

SULFOX A UOP process for the catalytic oxidation of aqueous sulfides. Not commercialized. 

Solutions containing several species (but mainly 84 and 85 ) are obtained upon digesting sulfur with aqueous sulfide. Solutions in methanol and ethanol may be prepared correspondingly. Salts of S (n = 2-8) can be obtained not only from such solutions but also from liquid NHj and in dry reactions. 

Sulfur reacts with aqueous sulfide to form polysulfides ... 

The sulfurization of semiconducting surfaces by dipping the material in aqueous sulfide solutions is generally used for the following applications ... 

Table 8 Some Geologically Important Complexes of Aqueous Sulfide Species116-117 129...

The ultrasonic irradiation of aqueous sulfide solutions was conducted with a Branson 200 sonifier operating at 20 kHz by Kotronarou et al. (1992). Reactions were performed in a 50-mL water-jacketed, stainless-steel cell from Sonics Materials. The temperature inside the reaction vessel was kept constant at 25°C. All irradiations were carried out in air-saturated solutions at t = 0. A Haake A80 water circulating and temperature-controlling system was used for temperature control. Hydrogen peroxide was analyzed fluoro-metrically. Deionized water was used to prepare all the solutions. 

Another preparative technique involves the ring-opening polymerization of cyclic polysulfides.56 For example, l-oxa-4,5-dithiacycloheptane polymerizes very rapidly at room temperature when treated with an aqueous sulfide (reaction (11)) ... 

For these reasons, it is useful to evaluate the effects of forming or not forming aqueous sulfide complexing agents and sulfide precipitates on radionuclide solubilities and aqueous speciation. Therefore, calculations were performed for key radionuclides for two cases (1) reduction of sulfate to sulfide and bisulfide was allowed to occur as Eh was lowered and (2) sulfate reduction as a function of Eh was prohibited so that sulfate was the only sulfur complexing agent available at all Eh values. 

Visible Light-Induced Formation of Addition of sulfite shown to enhance the clea-Hydrogen and Thiosulfate from vage of H2S into H2 and S. See also Refs. 495-Aqueous Sulfide/Sulfite Solutions 497 and Ref. 500 for follow-up work, in CdS Suspensions. 499... 

When aqueous sulfide solutions are heated with sulfur, solutions containing largely S2 and S2" are obtained. These polysulfide ions are the only ones stable in solution but a number of crystalline compounds with Sj ions from n = 3 to n = 8 can be prepared, especially by using large cations (e.g., Cs+, NH4 and enH + and R3NH+). In all those with n = 4 to 8 the S—S distances run from 2.00 to 2.11 A and the S—S—S angles are ca. 110°. Structures of some S2" ions are shown in Fig. 12-3. 

Bunte salts react with aqueous sulfide under mild conditions to give trisulfanes in high yield (equations 56 and 57). 

Bunte salts and thiosulfonates react with aqueous sulfide as shown in equations (56) and (57). When bifimctional Bunte... 

We have examined the photophysical and photocatalytic properties of solid solutions of sulfides based on ZnS according to the band engineering [36-40]. Solid solutions consisting of combinations of CuInS2, AgInS2, and ZnS show the high photocatalytic activities for H2 evolution from aqueous sulfide and... 

Early examples in the 1980s were aimed at the design of composite systems for photoelectrolytic generation of H2. Thus, Nafion and Si02 were used as supports for coprecipitated ZnS and CdS for photoassisted HER from aqueous sulfide media [407]. Subsequent work has addressed the mechanistic role of the support in the photoassisted HER [408]. Vectorial electron transfer was demonstrated in bipolar Ti02-Pt or CdSe-CoS photoelectrode panels arranged in series arrays for the photodecomposition of water to H2 and O2 [409, 410]. 

Polysulfanes with the general formula H2S (n — 2-S) are reactive oils in their pure state. Heating aqueous sulfide solutions yields polysulfide ions most typically with n = 3 or 4. The presence of sulfanes has been used to explain the high concentrations of sulfur compounds in some hydrothermal fluids (Migdisov and Bychkov, 1998). 

Compute CdS(s) (greenockite) solubility as a function of total aqueous sulfide ([S(-II)r]). 

If metals, particularly iron, are not available to precipitate the biogenic sulfide, then dissolved sulfide builds up in the pore waters and may even reach toxic levels. When iron is present the dissolved sulfide is significantly lower in concentration. The concentration profiles for dissolved sulfide in sediments often show a depletion in the upper layers and a maximum at a depth of a meter or less. The depletion is interpreted by Goldhaber and Kaplan (1974) to reflect reactions between iron oxide and dissolved sulfide to yield iron sulfides. As a consequence of different reactivities of iron oxides to aqueous sulfide, a depth may be reached where the sulfide production rate exceeds removal as iron sulfide. Volkov et al. (1972) reported that, in sediments off the Japan Depression, the free hydrogen sulfide concentration reaches as high as 150 mg h which is roughly 50% higher than that found in the Black Sea and is comparable to the maximum concentration observed at Saanich Inlet, British Columbia, by Nissenbaum et al. (1972). The... 

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