金属硫化物微生物氧化过程中硫的价态、物相转变及同位素地球化学意义

金属硫化物的氧化分解作用是导致矿山环境污染，酸性矿山排水、酸性岩石排水形成的重要因素。在此过程中，微生物的作用至关重要。选择安徽铜陵多金属矿山为研究区，通过矿物学分析手段，研究金属硫化物在矿山酸性环境下的氧化分解过程；硫化物的分解往往造成围岩中碳酸盐矿物的溶蚀并形成次生矿物，查明体系中原生矿物组合及次生矿物的种类和伴生关系，分析原生硫化物及不同次生硫酸盐矿物造成的S同位素分馏，寻找生物痕迹，进而探讨化学风化和微生物活动造成的矿物之间的相互转化，对矿山环境污染研究和治理提供理论依据；选择矿山环境中代表性微生物氧化亚铁硫杆菌和金属硫化物开展相互作用的模拟实验，系统分析微生物与硫化物反应界面特征及次生沉淀，通过监测反应过程中元素S的价态变化以及价态变化和不同阶段次生矿物造成的S同位素分馏，进而从微纳米尺度上探讨微生物－硫化物界面作用的微观机制，评价微生物－硫化物相互作用的环境效应。

The oxidation of sulfides is responsible for the generation of acid mine drainage and acid rock drainage, which leads to further contamination around polymetallic mining areas. It has been well demonstrated that microorganisms play crucial roles in the oxidation processes. The study area for this project is Tongling polymetallic deposit. Oxidative decomposition process of metal sulfide in acid mine environment is studied by mineralogical analysis methods. Decomposition of sulfides often results in the dissolution of carbonate minerals in the surrounding rock and the formation of secondary minerals. Identifying the species of primary sulfide minerals and secondary minerals, and the associated relationship between secondary minerals, analyzing sulfur isotope fractionation caused by primary sulfide and secondary sulfate minerals, these work are helpful to find traces of biological, chemical weathering and further explore the microbial activity in transformation of secondary minerals, which have important theoretical and practical significance in the remediation of pollution. We select representative bacteria (A.ferrooxidans) isolated in mine environment to interact with sulfides in laboratory, then investigate the properties of reaction interface between sulfides and bacteria and secondary minerals sediment generated during the experiments. By monitoring the valence changes of element S and its isotope fractionation caused by valence change and secondary minerals forming in different experimental stages, we may investigate the microscopic mechanism of microbial sulfide interaction in the micro-nano scale, and evaluate the environmental effect of microbial sulfide interaction.