Photopromoted oxidative dissolution of stibnite. (October 2015)

• Record Type: Journal Article
• Authors: Hu, Xingyun; He, Mengchang; Kong, Linghao
• Is Part Of: Applied geochemistry. Volume 61(2015:Oct.)
• Page Start: 53
• Page End: 61
• Publication Date: 2015-10
• Subjects: Environmental geochemistry -- Periodicals; Water chemistry -- Periodicals; Geochemistry -- Social aspects -- Periodicals; Geochemistry -- Periodicals; 551.9
• DOI: 10.1016/j.apgeochem.2015.05.014
• Languages: English
• ISSNs: 0883-2927

Abstract

Highlights: Light irradiation promoted the dissolution of stibnite. The oxidation of Sb(III) and H2 S induced the increase of dissolution of stibnite. Key photo-oxidants are O2, O 2 -, OH and h vb + . A photocatalytic oxidation mechanism for stibnite dissolution was proposed. This study help to elucidate the release pathway of antimony into the environment. Abstract: Light irradiation plays an important role in the oxidative dissolution of Sb2 S3 . 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 Sb2 S3 (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 Sb2 S3 . Photo-oxidants in the form of hydroxyl radicals ( OH ), superoxide anion free radicals ( O 2 - ) and photo-generated holes h vb + were produced in the photo-induced oxidative dissolution reaction of Sb2 S3 . Among these, O2 and O 2 - are the most significant oxidants. The main oxidation products of Sb2 S3 are Sb(V), S 0 and S 2 O 3 2 - . This study may help elucidate the geochemistry and fate of antimony in the environment.