Inhibition of Microbial Pyrite Oxidation by PropS-SH for the Control of Acid Mine Drainage

摘要

Acidithiobacillus ferrooxidans, an acidophilic sulfur and iron-oxidizing microorganism, plays animportant role in the oxidation of FeS2 and the formation of acid mine drainage (AMD). In this study,the stability of -mercaptopropyltrimethoxysilane(PropS-SH) treated pyrite in the presence ofAcidithiobacillus ferrooxidans was investigated by electrochemical techniques in conjunction withbioleaching approach. In addition, the chemical and morphological characteristics of pyrite before andafter coated by PropS-SH were analyzed with X-ray photoelectron spectrometer (XPS) and contactangle tests. The results from electrochemical tests indicated that the coating of PropS-SH significantlydecreased electrochemical activity of pyrite in bioleaching solutions. The results of bioleachingexperiments showed that PropS-SH coating could effectively suppress the release of S and Fe speciesfrom pyrite and inhibit the growth of bacteria. These results were attributed to the formation of ahydrophobic layer on pyrite surface by chemisorption of PropS-SH which could limite the contact ofbacteria with pyrite.