Abstract
The effects of pH, initial ferrous ion (Fe+2) concentrations and temperature on Fe+2 oxidation by Thiobacillus ferrooxidans were examined. Ferric ions (Fe+3) increased with increasing initial Fe+2 levels up to 2.6 g/L and, thereafter, initial Fe+2 concentrations higher than 2.6 g/L decreased Fe+3 levels. Complete Fe+2 oxidation, and also formation of higher Fe+3 amounts, could be only observed at pH 1.5. Greater pH values gave lower amounts of soluble Fe+3 because of the formed precipitates. The Fe+2 oxidation rate increased with increasing temperatures up to 301 K, and then decreased.