黄铁矿表面水分子和氧分子交互作用机制研究

Pyrite is the most common sulfide mineral on earth. It has great significance for the research in environment, mining, materials and life sciences. The oxidation of pyrite is the main cause for the acid mine drainage. The oxidation affects the flotation separation of non-ferrous metal sulfide minerals and coal, and has also become a problem limiting its application in many fields. However, the mechanism of pyrite oxidation remains to be identified. Is has been suggested that water participates in the oxidation process of pyrite. However, oxygen isotope results have shown that the oxygen in the sulfate produced by pyrite oxidation is mainly derived from water and part from molecular oxygen, but the proposed explanation for this result has not been proved. For the present project, the density functional theory method from the atomic level will be used to study the interaction mechanism of water-oxygen molecules on the surface of pyrite. The interaction details of water and oxygen molecules involved in the oxidation process of pyrite will be cleared and the complete pyrite oxidation model will be established. In addition, X-ray photoelectron spectroscopy and electrochemical study will be performed to obtain the surface chemical states and the evidence of the presence of reactive oxygen species during oxidation. The research results will provide theoretical reference and basis for the application of pyrite in the fields of environment, mining, materials and life sciences.

黄铁矿是地球上最常见的硫化矿物，它在环境、矿业、材料、生命科学等领域有重要研究和应用意义，它的氧化是造成矿山酸性废水排放的主要原因，影响了有色金属硫化矿物和煤的浮选分离，也成为限制其在其它领域应用的问题。然而，黄铁矿在水-氧环境下的氧化机制仍然有待查清。研究表明，水参与了黄铁矿的氧化过程，但氧同位素检测表明，氧化后产生的硫酸根中的氧除了主要自于水还有部分来自于氧气，而提出的相关解释并没有被证明。本项目拟采用密度泛函理论方法，从原子级别研究水-氧分子在黄铁矿表面的交互作用机制，查清水分子和氧分子参与黄铁矿氧化过程的细节，建立完整的黄铁矿氧化模型；另外，项目拟对氧化产物进行X射线光电子能谱和黄铁矿电极的电化学行为研究，获得矿物表面化学态和活性氧类物质存在的证据。通过该项目研究，为黄铁矿在环境、矿业、材料、生命科学等领域的作用提供理论参考和依据。

黄铁矿是地球上最常见的硫化矿物，它在环境、矿业、材料、生命科学等领域有重要研究和应用意义，它的氧化是造成矿山酸性废水排放的主要原因，影响了有色金属硫化矿物和煤的浮选分离，也成为限制其在其它领域应用的问题。本项目采用密度泛函理论方法，从原子级别研究水-氧分子在黄铁矿表面的交互作用机制，查清了水分子和氧分子参与黄铁矿氧化过程的细节，建立了完整的黄铁矿氧化模型；研究了黄铁矿表面水化结构；研究了硫空位缺陷对表面氧化的影响；另外，对氧化产物进行了X射线光电子能谱和黄铁矿电极的电化学行为研究。研究表明，水分子参与了黄铁矿的氧化过程，在黄铁矿表面与氧分子交互作用后极容易在硫位上解离，造成硫酸盐中的氧来主要自于水分子，这证实了同位素检测结果；在接触表面上，水分子吸附紧密且规则，厚度约5埃，而次外层约5埃厚度的水分子的吸附仍然会受到表面的影响而呈一定的规则，远表面的水分子呈无序状态；硫空位的存在使水分子的吸附更强，但没有发生解离，只有在氧存在时才能发生解离；通过XPS和电化学研究，证明表面氧化过程中有羟基自由基的存在，获得了矿物表面化学态，证实了活性氧类物质存在的证据。通过该项目研究，为黄铁矿在环境、矿业、材料、生命科学等领域的作用提供理论参考和依据。