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The important sulfur cycle is a biogeochemical cycle in which the sulfur moves between rocks, waterways and living systems. It is important in geology as it affects many minerals and in life because sulfur is an essential element (), being a constituent of many proteins and cofactors, and sulfur compounds can be used as oxidants or reductants in microbial respiration. [1]
The sulfur and iodine compounds are recovered and reused, hence the consideration of the process as a cycle. This S–I process is a chemical heat engine. Heat enters the cycle in high-temperature endothermic chemical reactions 2 and 3, and heat exits the cycle in the low-temperature exothermic reaction 1. The difference between the heat ...
The process flow is the same as that for an HDS unit. Using pyridine (C 5 H 5 N), a nitrogen compound present in some petroleum fractionation products, as an example, the hydrodenitrogenation reaction has been postulated as occurring in three steps: [17] [18]
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. The multi-step Claus process recovers sulfur from the gaseous hydrogen sulfide found in raw natural gas ...
Hydrogen sulfide is a central participant in the sulfur cycle, the biogeochemical cycle of sulfur on Earth. [ 105 ] In the absence of oxygen , sulfur-reducing and sulfate-reducing bacteria derive energy from oxidizing hydrogen or organic molecules by reducing elemental sulfur or sulfate to hydrogen sulfide.
The sulfur cycle in marine environments has been well-studied via the tool of sulfur isotope systematics expressed as δ 34 S. The modern global oceans have sulfur storage of 1.3 × 10 21 g, [92] mainly occurring as sulfate with the δ 34 S value of +21‰. [93] The overall input flux is 1.0 × 10 14 g/year with the sulfur isotope composition ...
A biogeochemical cycle, or more generally a cycle of matter, [1] is the movement and transformation of chemical elements and compounds between living organisms, the atmosphere, and the Earth's crust. Major biogeochemical cycles include the carbon cycle, the nitrogen cycle and the water cycle. In each cycle, the chemical element or molecule is ...
Sulfur assimilation is the process by which living organisms incorporate sulfur into their biological molecules. [1] In plants, sulfate is absorbed by the roots and then transported to the chloroplasts by the transipration stream where the sulfur are reduced to sulfide with the help of a series of enzymatic reactions.