Photopromoted oxidative dissolution of stibnite

•Light irradiation promoted the dissolution of stibnite.•The oxidation of Sb(III) and H2S induced the increase of dissolution of stibnite.•Key photo-oxidants are O2, O2-,OH and hvb+.•A photocatalytic oxidation mechanism for stibnite dissolution was proposed.•This study help to elucidate the release pathway of antimony into the environment.

Light irradiation plays an important role in the oxidative dissolution of Sb2S3. A qualitative mechanism was proposed through simulated experiments to describe the dissolution reaction under various ambient conditions, specifically darkness/light and aerobic/anaerobic conditions. The pH-dependent solubility of Sb2S3(s) and photo-induced oxidative dissolution are two types of reaction mechanisms. The oxidation of Sb(III) and its sulfides by light irradiation induce the prompt dissolution of Sb2S3. Photo-oxidants in the form of hydroxyl radicals (OH), superoxide anion free radicals (O2-) and photo-generated holes hvb+ were produced in the photo-induced oxidative dissolution reaction of Sb2S3. Among these, O2 and O2- are the most significant oxidants. The main oxidation products of Sb2S3 are Sb(V), S0 and S2O32-. This study may help elucidate the geochemistry and fate of antimony in the environment.