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Simplified diagram of the Hybrid sulfur cycle. The hybrid sulfur cycle (HyS) is a two-step water-splitting process intended to be used for hydrogen production.Based on sulfur oxidation and reduction, it is classified as a hybrid thermochemical cycle because it uses an electrochemical (instead of a thermochemical) reaction for one of the two steps.
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 ...
The mechanism for the action of the catalyst comprises two steps: Oxidation of SO 2 into SO 3 by V 5+: 2SO 2 + 4V 5+ + 2O 2− → 2SO 3 + 4V 4+ Oxidation of V 4+ back into V 5+ by dioxygen (catalyst regeneration): 4V 4+ + O 2 → 4V 5+ + 2O 2−; Hot sulfur trioxide passes through the heat exchanger and is dissolved in concentrated H 2 SO 4 in ...
An example is the Latimer diagram for sulfur at pH 0 where the electrochemical oxidation state +2 for sulfur puts HS 2 O − 3 between S and H 2 SO 3: Systematic oxidation state is chosen from close alternatives as a pedagogical description.
The fractionations of oxygen produced by sulfur disproportionation from elemental sulfur have been found to be higher, with reported values from 8 to 18.4‰, which suggests a kinetic isotope effect in the pathways involved in oxidation of elemental sulfur to sulfate, although more studies are necessary to determine what are the specific steps ...
Sulfur is metabolized by all organisms, from bacteria and archaea to plants and animals. Sulfur can have an oxidation state from -2 to +6 and is reduced or oxidized by a diverse range of organisms. [1] The element is present in proteins, sulfate esters of polysaccharides, steroids, phenols, and sulfur-containing coenzymes. [2]
A schematic process flow diagram of a basic 2+1-reactor (converter) SuperClaus unit is shown below: Schematic flow diagram of a straight-through, 3 reactor (converter), Claus sulfur recovery unit. The Claus technology can be divided into two process steps, thermal and catalytic.
SO 2− 4 + 4H 2 → H 2 S + 2H 2 O + 2OH −. Sulfide Oxidation. Under aerobic conditions, sulfide is oxidized to sulfur and then sulfate by sulfur oxidizing bacteria, such as Thiobacillus, Beggiatoa and many others. Under anaerobic conditions, sulfide can be oxidized to sulfur and then sulfate by Purple and Green sulfur bacteria. H 2 S → S ...