Akinetic study of the depyritization of oil shale HCl-kerogen concentrate by Thiobacillus ferrooxidans at different temperatures

The results of kinetic studies of bacterial depyritization of HCl-kerogen concen- trate of Aleksinac (Serbia) oil shale by the chemolithoautotrophic thionic bacteria Thio- bacillus ferrooxidans under discontinuous laboratory conditions at various temperatures (0, 20, 28 and 37 oC) at a pH of ca. 1.5 are presented in this paper. Low pH prevents the occur- rence of the precipitation of iron(III)-ion hydrolysis products on the substrate particles and thereby reduces the process efficiency. Bacterial depyritization is developed as per kinetics of the first order. The activation energy which points to a successive mechanism of pyrite biooxidation, was computed from the Arrhenius plot. The biochemical kinetics indicators point to a high affinity of the bacteria toward pyrite but small values of Vmax, which are prob- ably the result of decelerated metabolic processes due to the low pH value of the environ- ment resp. the large difference of the pH between the external medium and the cell interior.