Sulfur isotopic fractionation between sulfur and sulfuric acid in the hydrothermal solution of sulfur dioxide

Abstract

Sulfur and sulfur compounds involved in the chemical reaction, 3H₂SO₃= 2H₂SO₄+S+H₂O in the temperature range from 150 to 300°C have been quantitatively determined. After the disproportionation reaction of sulfurous acid is completed, sulfur decreases according to the chemical reaction, 4S+4H₂O = 3H₂S+H₂SO₄. These two reactions may be responsible for the production of sulfuric acid in hot spring water. ³⁴S is enriched in sulfuric acid and depleted in sulfur revealing 16.1 to 21.1‰ fractionation between them. This would account for the enrichment of ³⁴S in sulfuric acid encountered in hot spring water.