Sulfide Sulfite

Lead shows excellent resistance to phosphoric and sulfuric acid in almost all concentrations and at elevated temperatures, as well as to sulfide, sulfite, and sulfate solutions. The corrosion film is insoluble lead sulfate which rapidly reforms if it is damaged. Lead is also resistant to chlorides, fluorides, and bromates at low concentrations and low temperatures. However, because lead is soluble in nitric and acetic acids, it is not resistant to these acids. 

Chromium Removal System. Chlorate manufacturers must remove chromium from the chlorate solution as a result of environmental regulations. During crystallization of sodium chlorate, essentially all of the sodium dichromate is recycled back to the electrolyzer. Alternatively, hexavalent chromium, Cr, can be reduced and coprecipitated in an agitated reactor using a choice of reducing agents, eg, sodium sulfide, sulfite, thiosulfate, hydrosulfite, hydrazine, etc. The product is chromium(III) oxide [1333-82-0] (98—106). Ion exchange and solvent extraction techniques have also... 

Sulfur is counted twice—as sulfur and as sulfate. Some of this sulfur exists as sulfides, sulfites, and forms other than sulfate. 

The solubility of a solid can be increased by removing one of its ions from solution acid can be used to dissolve a hydroxide, sulfide, sulfite, or carbonate precipitate and nitric acid can be used to oxidize metal sulfides to sulfur and a soluble salt. 

Photocatalytic Hj by Direct Sunlight from Sulfide/Sulfite Solution... 

Cerveramarch, S.C., Borrell, L., Gimenez, J., Simarro, R., Andujar, J.M. 1992. Solar hydrogen photoproduction from sulfide sulfite substrate. Int J Hydrogen Energy 17 683-688. 

Koca, A., Sahin, M. 2002. Photocatalytic hydrogen production by direct sun light from sulfide/ sulfite solution. Int J Hydrogen Energy 27 363-367. 

Protection from Oxidation.—The most common case of oxidation among inorganic compounds occurs with salts in which the metal has two stages of oxidation and tends to pass from the lower to the higher as a result of atmospheric oxidation. The salts of iron, copper, tin, mercury, and chromium are examples. In other cases, the acid radical tends to undergo oxidation, as is true with sulfides, sulfites, phosphites, and nitrites. 

Environmental applications require detoxification of hazardous substances to a level of parts per million (ppm) and even parts per billion (ppb). These purity levels, which were rarely considered in product synthesis, are now possible for wastewater due to Fenton s reagent. Fenton s oxidant is cost effective and relatively fast in destroying many toxics (Bigda, 1996). It attacks all reactive substrate concentrations under acidic conditions. Hydrogen peroxide is used to remove such contaminants as cyanide, sulfides, sulfites, chrome, and heavy metals by varying batch conditions. With an iron catalyst, the process often oxidizes organics, as well as reducing hexavalent chrome to trivalent precipitable form. 

Several ions interfere in this analysis. These include bromide, iodide, cyanide, sulfide, sulfite, and thiosulfate. The latter three ions may be removed by treatment with H202. The sample should be diluted when iron and orthophosphate are present at concentrations above 10 mg/L. 

Diorgano tellurium dihalides react with reducing agents (sodium sulfide, sulfites, hydrazine, thiourea dioxide, sodium borohydride) under mild conditions to give the corresponding diorgano tellurium derivatives in high yields. 

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... 

The nomenclature reform of the French chemists was of fundamental importance, replacing the old body-spirit terminology with new terms, based on oxygen. The calx was now termed the oxide, and the spirit of vitriol became sulfuric acid. The assumption that oxygen was the acid generator, as its name implied, was flawed, but the systematic nomenclature based on the increase of acidity with increase of oxygen content lived on, e.g. the acidic component of the sulfides, sulfites, and sulfates. The definition of a chemical element as the latest term whereat chemical analysis has arrived ... 

Handa, A. C., Johri, K. N. Micro determination of sulfide, sulfite, sulfate and thiosulfate by thin-layer chromatography and ring-colorimetry. Talanta 20, 219 (1973)... 

Because of the difficulties involved in removing oxygen (and keeping it removed) from the sample and eluent solutions, most applications of electrochemical detectors in ion chromatography have been the detection of relatively easily oxidized species (cyanide sulfide, sulfite, nitrite, or phenols, for example). 

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