Sulfide inorganic

K. C. Mills, Thermodynamic Data for Inorganic Sulfides, Selenides and Tellurides, Butterworths, London, 1974. 

Yagi laid the foundation for the enzymology of CODH when he discovered an enzymatic activity in sulfate-reducing bacteria that oxidizes CO to CO2 (118). Twenty-five years later, the first CODH was purified to homogeneity (119, 120). The homogeneous C. thermo-aceticum CODH was shown to contain 2 mol of nickel, 12 iron, 1 zinc, and 14 acid-labile inorganic sulfide per afS dimeric unit (120). 

Davies DA, Vecht A, Silver J, Marsh PJ, Rose JA (2000) A novel method for the preparation of inorganic sulfides and selenides 1. Binary materials and Group 11-Vl phosphors. J Electrochem Soc 147 765-771... 

Mills, K.C. (1974) Thermodynamic data for inorganic sulfides, selenides and tellurides. London Butterworths. 

Workers employed at facilities that manufacture or use hydrogen sulfide in the production process are especially prone to exposure. Such industries include the manufacture of rayon textiles, lubricants, pulp and paper, and sulfuric acid and inorganic sulfides. Workers in facilities where hydrogen sulfide is produced as a byproduct, such as farms with manure storage pits, petroleum or natural gas drilling operations, landfills, and waste-water treatment plants, may also be exposed to high levels. 

Shell s microbiological desulfurization process is carried out by mixing coal with an aqueous biocatalyst solution [158], The coal considered in this invention concerns bituminous coal containing inorganic sulfur (pyritic).This process seems to be applicable to refinery pet-coke, which contains sulfur in the form of inorganic sulfides. Nowadays, when coke has become one of the major products of heavy oil and bitumens refining, such desulfurization processes might have potential uses. 

The first example describes the extraction of zinc from weak acid solutions. In the manufacture of rayon, rinse waters and other zinc-containing liquid effluents are produced. The total liquid effluent in a rayon plant may amount to several per minute with a zinc concentration of 0.1-1 gdm and pH normally 1.5-2. In addition to zinc, the effluent contains surface-active agents and dirt (organic fibers and inorganic sulfide solids). The use of both precipitation (OH and S ) and ion exchange has been reported to remove zinc from such effluents. In addition, solvent extraction has successfully been used to recycle the zinc back to the operation. 

The most important applications of hydrogen sulfide involve the production of sodium sulfide and other inorganic sulfides. Hydrogen sulfide obtained as a by-product often is converted into sulfuric acid. It also is used in organic synthesis to make thiols or mercaptans. Other applications are in metallurgy for extracting nickel, copper, and cobalt as sulfides from their minerals and in classical qualitative analytical methods for precipitation of many metals (see Reactions). It also is used in producing heavy water for nuclear reactors. 

Aconitase was the third protein and the first enzyme for which a 3Fe cluster was postulated by Mbssbauer spectroscopy (Kent et al., 1982) the meticulous inorganic sulfide analysis by Beinert et al. (1983) established the composition of this class of cluster as 3Fe 4S. Although the 3Fe form of the protein is inactive, it can be reactivated by the addition of Fe " under anaerobic reducing conditions (Kennedy et al., 1983). The resulting cluster was shown by Mbssbauer spectroscopy to be similar to ferre-doxin 4Fe 4S clusters in the +2 oxidation state the more reduced cluster was only 30% active. Mbssbauer spectroscopy also indicated that... 

Ferredoxins with 4Fe4S clusters are small, low potential electron carriers that function in bacterial electron transfer. Like the binuclear clusters, each tetranu-clear cluster can reversibly accept a single electron. The tetranuclear prosthetic group is a cubane with iron and acid-labile inorganic sulfide groups at alternate vertices the four iron atoms and the four sulfides form interpenetrating tetrahedra of slightly different sizes. 

The stability of the inorganic sulfides appears to be a major factor in the disposition of trace metals in the feed. As examples, lead, tin, cadmium and nickel can be largely recovered as the sulfides in most energy conversion processes, although many forms of these materials are volatile. ... 

A new representative of a multicopper cluster in a protein is Cuz in nitrous oxide reductase. As was discussed above this enzyme contains a binuclear CuA centre as in COX. While the latter in addition has CuB in the form of a copper-heme group, N20 reductase has Cuz which is the site of dinitrogen formation from the substrate N20. Recently a central inorganic sulfide has been found as a ligand to copper and multiple forms of Cuz were detected in the enzyme from Paracoccus pantotrophus.134 More recently a tetranuclear copper cluster with X-S bridges was proposed as structure for Cuz..135... 

Carbon monoxide oxidoreductase has a high molecular weight values between 150,000 and 460,000 have been reported (25). Analysis of the enzyme from C. thermoaceticum indicated a composition of 2 atoms of Ni, 1 Zn, 11 Fe, and 14 inorganic sulfide per dimeric enzyme, with a relative molecular mass of approximately 150,000 Da (23). 

NADH dehydrogenase and succinate dehydrogenase also contain Fe atoms that are bound by the S atoms of cysteine residues of the protein, in association with additional, inorganic sulfide atoms. Structures of these complexes are shown in figure 10.19. Succinate dehydrogenase has three iron-sulfur centers, one with a [2Fe-2S] cluster, one with [4Fe-4S], and one with a cluster containing 3 Fe atoms and 3 (or possibly 4) sulfides. Iron-sulfur centers undergo one-electron oxidation-reduction reactions. 

Finally, removal of the sulfate ion creates a new contamination problem. In connection with this, sulfate reduction bacteria for the complete removal of sulfur are being examined. The conversion of the organic sulfide into inorganic sulfide will be one future objective of this study. 

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