Potential of Thiobacillus ferrooxidans for waste gas purification. Part 1. Kinetics of continuous ferrous iron oxidation

Abstract

Kinetic data of ferrous iron oxidation by Thionacillus ferrooxidans were determined. The aim was to remove H2S (<0.5 ppm) from waste gas by a process proposed earlier. Kinetic data necessary for industrial scale-up were investigated in a chemostat airlift reactor (dilution rate 0.02–0.12 h−1; pH 1.3). Due to the low pH, ferric iron precipitation and wall growth could be avoided. The maximum ferrous iron oxidation rate of submersed bacteria was 0.77 g 1−1 h−1, the maximum specific growth rate about 0.12 h−1 and the yield coefficient was found to be 0.007 g g−1 Fe2+. The specific O2 demand of an exponentially growing, ironoxidizing batch culture was 1.33 mg O2 mg−1 biomass h−1. The results indicate that a pH of 1.3 has no negative influence on the kinetics of iron oxidation and growth.