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The oxidation of reduced sulfur compounds is performed exclusively by Bacteria and Archaea.All the Archaea involved in this process are aerobic and belong to the Order Sulfolobales, [19] [20] characterized by acidophiles (extremophiles that require low pHs to grow) and thermophiles (extremophiles that require high temperatures to grow).
The sulfidation of tungsten is a multiple step process. The first step is an oxidation reaction, converting the tungsten to a tungsten bronze on the surface of the object. The tungsten bronze coating is then converted to a sulfide. [3]
Sulfur can be found under several oxidation states in nature, mainly −2, −1, 0, +2 (apparent), +2.5 (apparent), +4, and +6. When two sulfur atoms are present in the same polyatomic oxyanion in an asymmetrical situation, i.e, each bound to different groups as in thiosulfate, the oxidation state calculated from the known oxidation state of accompanying atoms (H = +1, and O = −2) can be an ...
These processes typically produce hydrogen sulfide as a byproduct, which can go on to serve as an electron donor in sulfur oxidation. [11] Sulfate reduction by sulfate-reducing bacteria is dissimilatory; the purpose of reducing the sulfate is to produce energy, and the sulfide is excreted.
The sulfide ion does not exist in aqueous alkaline solutions of Na 2 S. [3] [4] Instead sulfide converts to hydrosulfide: S 2− + H 2 O → SH − + OH −. Upon treatment with an acid, sulfide salts convert to hydrogen sulfide: S 2− + H + → SH − SH − + H + → H 2 S. Oxidation of sulfide is a complicated process.
The Claus process is the most significant gas desulfurizing process, recovering elemental sulfur from gaseous hydrogen sulfide. First patented in 1883 by the chemist Carl Friedrich Claus , the Claus process has become the industry standard.
Supergene processes include the predominance of meteoric water circulation (i.e. water derived from precipitation) with concomitant oxidation and chemical weathering. The descending meteoric waters oxidize the primary (hypogene) sulfide ore minerals and redistribute the metallic ore elements.
Generally, the oxidation of sulfide occurs in stages, with inorganic sulfur being stored either inside or outside of the cell until needed. This two step process occurs because energetically sulfide is a better electron donor than inorganic sulfur or thiosulfate, allowing for a greater number of protons to be translocated across the membrane.