Pyrite biooxidation: electrochemical and kinetic data

摘要

Studies on pyrite oxidation by Thiobacillus ferrooxidans, using a compact pyrite electrode, resulted in detection of 14 exchanged electrons. This indicates that the pyrite biooxidation to sulfate ions occurred at the pyrite surface without the formation of any sulfur intermediates. Exchange current density showed that the pyrite biooxidation rate was higher by one order of magnitude as compared to conditions without bacteria. Assuming sulfate is the final product, the initial rate of pyrite concentrate oxidation by ferric iron (up to 180 mM) was similar to the rate of pyrite concentrate oxidation by T.ferrooxidans in the absence of any significant ferric iron. Electrochemical and kinetic studies supported the indirect mechanism of pyrite oxidation based on iron-oxidizing activity of T.ferrooxidans.