Effective Hydrogen Generation from H₂S by Utilizing the Sulfur Cycle (2)

Conversion Method from Elemental Sulfur to H₂S by Biological Reaction

Abstract

Photocatalytic decomposition of hydrogen sulfide (H₂S) into hydrogen (H₂) by using the stratified type photocatalyst is considered as efficient route for the conversion of natural energy (solar energy) into clean energy (H₂) . This reaction obeyed to next formula; 2HS^-→2H⁺ + S₂^2- + 2e^-→H₂↑+ S₂^2-. To construct the continuous system, effective conversion route from S₂^2-ion into H₂S gas should be developed. In other word, sulfur cycle system should be constructed.
In this report, conversion route from sulfur compounds (elemental sulfur and Na₂SO₄) into H₂S by utilizing biological reaction was studied. H₂S gas was stably synthesized until c.a.5% in the case of elemental sulfur addition, while it was c.a. 2% in the case of Na₂SO₄. Rate of biological reaction was seriously decreased if concentration of H₂S was over these values because of its toxicity. Conversion efficiency was higher in the case of elemental sulfur addition since impediment of sodium ion was not progressed.