硫代五价砷在黄铁矿(001)晶面吸附的第一性原理研究

Adsorption of Thioarsenate on the (001) Surface of Pyrite (FeS2)：A First-Principles Study

中文关键词: 硫代五价砷  黄铁矿  构型  吸附能  DFT计算

英文关键词: thioarsenate  pyrite  configuration  adsorption energy  DFT calculations

中文摘要:

      硫代砷是地下水中重要的砷形态,其在黄铁矿表面的吸附解吸是决定砷迁移性的重要机制。然而,由于硫代砷具有复杂的形态,难以通过实验研究在分子水平理解并预测其在黄铁矿表面的吸附性质。本研究采用密度泛函理论(DFT)计算方法对不同硫代五价砷在黄铁矿表面的吸附构型和吸附能开展了研究。结果表明,多种硫代砷能够在黄铁矿(0 0 1)晶面上形成多种稳定吸附构型；质子化状态、构型、结合位点是决定硫代砷在黄铁矿表面吸附的重要因素；硫代砷在吸附过程中会发生明显的内部结构变化。研究成果对认清地下水等还原环境中砷的形态转化及矿物-水界面吸附解吸机理提供了科学基础。

英文摘要:

      Thioarsenates are important arsenic species in groundwater, and their adsorption and desorption on pyrite surfaces are important mechanisms determining arsenic mobility. However, due to the complex nature of thioarsenates, it is difficult to understand and predict their adsorption properties on pyrite surfaces at a molecular level through experimental studies. In this study, density functional theory (DFT) calculations were used to investigate the adsorption configurations and energies of different thioarsenic species on pyrite surfaces. The results showed that various thioarsenates can form multiple stable adsorption configurations on the (0 0 1) crystal surface of pyrite. The protonation state, configuration, and binding sites are important factors determining the adsorption of thioarsenates on pyrite surfaces, and significant internal structural changes occur during the adsorption process. The research findings provide a scientific basis for understanding the transformation of arsenic species and the adsorption/desorption mechanism at the mineral-water interface in reducing environments such as groundwater.