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.