控电位体系下微生物与黄铁矿的“接触作用”研究

黄铁矿氧化与硫化矿生物冶金及矿山酸性水治理密切相关。微生物与黄铁矿的“非接触作用”假说已获得广泛共识；但是微生物的“接触作用”，即通过吸附在黄铁矿表面的微生物及其胞外聚合物EPS，对黄铁矿氧化的贡献及其作用条件尚存争论和疑点。采用自主开发的有菌体系恒电位动力学实验装置与方法，恒定微生物“非接触作用”背景，通过有菌/无菌黄铁矿氧化动力学对照，来判定“接触作用”对黄铁矿氧化的贡献；采用激光共聚焦（CLSM）等手段，查证有菌体系中微生物在矿物表面吸附并形成生物膜和EPS；采用高效液相色谱（HPLC）等测定EPS中活性组分及含量，探究EPS活性组分与溶液电位和黄铁矿氧化动力学的内在联系，获得“接触作用”发生的生物/化学条件；结合黄铁矿氧化过程表面组份表征，探究微生物“接触作用”机理。研究可望提升黄铁矿氧化过程中微生物作用方式及其机理的认识，并形成有菌体系中促进/抑制黄铁矿氧化的新技术原型。

Regulation of pyrite oxidation is related to the economically extraction of sulfide ore and also the controlling of acid mine drainage. The non-contact mechanism that promotion of pyrite oxidation by ferric iron regeneration and redox potential elevation under microbial activity, now is widely accepted. The contact mechanism of the attachment of microbes on the mineral surface with the EPS layer serving as reaction space for ferrous ions oxidation, are still not clear about its contribution and action condition. In this program, the novel method and independent developed kinetic instruments which can control the chemical environment is used to elucidated the relative contribution of non-contact and contact mechanism during microbial oxidation of pyrite; confocal laser scanning microscopy (CLSM), atomic force microscopy (AFM) and scanning electron microscope (SEM) are used to investigate the extracellular polymeric substances (EPS) formation of mixed and pure standard microbes; high-pressure liquid chromatography (HPLC), fourier transform infrared spectroscopy (FTIR) and raman spectroscopy (Raman) are used to determine the content of the EPS, and to find out its active component, the linkage to leaching kinetics and finally get boundary microbial and chemical conditions of contact mechanism. Combining with the characterization of surface composition during pyrite oxidation process, the contact mechanism is fully elucidated. This program will benefit to the fully understanding of the mechanism of microbial assisted pyrite oxidation, and also help to form the technology prototype of pyrite oxidation controlling under acidic microbial condition both in sulfide mineral processing and acid mine drainage controlling.