Abiotic aerobic oxidation pathways of stibnite revealed by oxygen and sulfur isotope systematics of sulfate  

作　　者：Ningjie He Shu Li Xiaoqian Li Yaning Tang Jiaxue Yang Jianwei Zhou 

机构地区：[1]School of Environment Studies,China University of Geosciences,Wuhan 430074,China [2]Key Laboratory of Mine Ecological Effects and Systematic Restoration,Ministry of Natural Resources,Beijing 100081,China [3]State Environmental Protection Key Laboratory of Source Apportionment and Control of Aquatic Pollution,Ministry of Ecology and Environment,Wuhan 430074,China [4]Institute of Geological Survey,China University of Geosciences,Wuhan 430074,China

出　　处：《Journal of Environmental Sciences》2025年第1期83-92,共10页环境科学学报(英文版)

基　　金：supported by the National Natural Science Foundation of China(No.41672245);the National Key Research and Development Program of China(No.2022YFC3702201).

摘　　要：The environmental threat posed by stibnite is an important geoenvironmental issue of current concern.To better understand stibnite oxidation pathways,aerobic abiotic batch experiments were conducted in aqueous solution with varyingδ^(18)O_(H_(2)O) value at initial neutral pH for different lengths of time(15-300 days).The sulfate oxygen and sulfur isotope compositions as well as concentrations of sulfur and antimony species were determined.The sulfur isotope fractionation factor(△^(34)S_(SO4-stibnite))values decreased from 0.8‰to-2.1‰during the first 90 days,and increased to 2.6‰at the 180 days,indicating the dominated intermediate sulfur species such as S_(2)O_(3)^(2-),S0,and H_(2)S(g)involved in Sb2S3 oxidation processes.The incorporation of O into sulfate derived from O_(2)(~100%)indicated that the dissociated O_(2)was only directly adsorbed on the stibnite-S sites in the initial stage(0-90 days).The proportion of O incorporation into sulfate from water(27%-52%)increased in the late stage(90-300 days),which suggested the oxidation mechanism changed to hydroxyl attack on stibnite-S sites promoted by nearby adsorbed O_(2)on stibnite-Sb sites.The exchange of oxygen between sulfite and water may also contributed to the increase of water derived O into SO42-.The new insight of stibnite oxidation pathway contributes to the understanding of sulfide oxidation mechanism and helps to interpret field data.

关 键 词：Sulfide oxidation δ^(34)S_(SO4) δ^(18)O_(SO4) Oxygen source of sulfate 

分 类 号：X703[环境科学与工程—环境工程]