Closed Cycle Photocatalytic Process for Decomposition of Hydrogen Sulfide to Its Constituent Elements

摘要

In a previous report, we described how photocatalyst materials such as cadmium suflide, CdS, modified with co-catalysts such as Pt, could perform an partial photo-oxidation of sulfide ion to sulfur and at the same time reduce water to make H_2. The sulfur is complexed as polysulfide ion, Sn~(2-), and recovered inside a H_2S-driven scrubber at neutral pH. Recent studies have shown that the polysulfide ion exists principally as the disulfide, which is important with respect to the spectral windown of the working fluid that the photoreactor light source must penetrate. It has also been shown that the net chemical, reaction inside the photoreactor, while facilitated at high pH, is itself pH neutral, so that evacuation, stripping, or some other type of removal of excess H_2S from the scrubber effluent is necessary to prepare it for the photoreactor.