Effect of Ni~(2+), V~(4+) and Mo~(6+) concentration on iron oxidation by Acidithiobacillus ferrooxldans

摘要

The ferrous oxidation ability of Acidithiobacillus ferrooxidans was studied in the presence of Ni~(2+), V~(4+) and Mo~(6+) in 9 K media in order to implement the culture in the bioleaching of spent catalyst. The rate of iron oxidation decreased with increasing concentration of metal ions, but the rate of inhibition was metal-ion dependent. The tolerance limit was critical at a concentration of 25 g/L Ni~(2+), 5 g/L V~(4+) and 0.03 g/L Mo~(6+). The growth rate of microorganisms was negligible at concentrations of 6 g/L V~(4+) and 0.04 g/L Mo~(6+). Levels and degree of toxicity of these ions have been quantified in terms of a toxicity index (TI). The toxicity order of metal ions was found to be Mo~(6+)>V~(4+)>Ni~(2+). The significance and relevance of multi-metal ion tolerance in Acidithiobacillus ferrooxidans has been highlighted with respect to bioleaching of spent refinery catalyst.