Activity of zero-valent sulfur in sulfidic natural waters

Activity of zero-valent sulfur in sulfidic natural waters

BACKGROUND Ionic and molecular carriers of dissolved (filter-passing) zero-valent sulfur (S0) in anaerobic natural waters include polysulfides, Sn2-, molecular S8(aq), organic macromolecules and certain higher valent thioanions. Because S0 is rapidly transferred among these various carriers, its biogeochemical roles in such processes as dehalogenation of organic compounds, chelation of trace me...

Speciation and Removal Mechanisms of Rhenium in Anoxic Waters: Roles of Zero-Valent Sulfur, Mineral Oxide Catalysis, and Pyrite Surfaces

Speciation of arsenic in sulfidic waters

Formation constants for thioarsenite species have been determined in dilute solutions at 25 uC, SH2S from 10 to 10 M, SAs from 10 to 10 M, and pH 7 and 10. The principal inorganic arsenic species in anoxic aquatic systems are arsenite, As(OH)3 , and a mononuclear thioarsenite with an S/As ratio of 3 : 1. Thioarsenic species with S/As ratios of 1 : 1, 2 : 1, and 4 : 1 are lesser components in su...

Self-assembly of biomorphic carbon/sulfur microstructures in sulfidic environments

In natural and laboratory-based environments experiencing sustained counter fluxes of sulfide and oxidants, elemental sulfur (S(0))-a key intermediate in the sulfur cycle-can commonly accumulate. S(0) is frequently invoked as a biomineralization product generated by enzymatic oxidation of hydrogen sulfide and polysulfides. Here we show the formation of S(0) encapsulated in nanometre to micromet...

Mercury methylation by Desulfovibrio desulfuricans ND132 in the presence of polysulfides.

The extracellular speciation of mercury may control bacterial uptake and methylation. Mercury-polysulfide complexes have recently been shown to be prevalent in sulfidic waters containing zero-valent sulfur. Despite substantial increases in total dissolved mercury concentration, methylation rates in cultures of Desulfovibrio desulfuricans ND132 equilibrated with cinnabar did not increase in the ...