The effect of temperature on the kinetics of ferrous-iron biooxidation by Leptospirillum ferriphilum in a packed column bioreactor
The microbial ferrous-iron oxidation kinetics of Leptospirillum ferriphilum were studied at substrate loading rate of 0. 17 -0.5 g/(L-h) (dilution rates 0.033 - 0. 1 h~ ). The study was conducted in a packed column with a view to investigate the kinetics in a system which simulates the solution flow dynamics of a typical heap bioleach operation. Marble balls, 15 mm in diameter, were used as reactor packing. The microbial oxidation kinetics was investigated in a continuous mode at desired loading rates. The pH of the bioreactor was maintained at pH 1. 45 ±0. 05 and the aeration at 15 mL/s. Both Monod and Hansford models were used to describe accurately the kinetics of ferrous-iron biooxidation to the same accuracy. The effect of temperature on the kinetic parameters was investigated at 25 , 30 and 35℃. The results showed that the maximum rate of microbial ferrous-iron oxidation ( rmaxFe2+ ) and kinetic constant (KFe2+ ) increase linearly with an increase in temperature within the range studied. The maximum oxidation rate, rmaxFe2+ =15. 10 mmol/(L·h) , obtained at 35℃ is greater than the rate obtained in a similar study conducted in a continuous stirred tank bioreactor. The result also shows that Arrhenius equation can be used to describe the relationship of maximum overall microbial oxidation rate with temperature. However, a much lower activation energy (Ea =20. 97 kJ/mol) was obtained which is indicative of a system that is limited by diffusion factors. This study shows that the microbial oxidation kinetics of ferrous-iron by L. ferriphilum is more likely to be promoted in simulated heap bioleach system compared to an agitated vessel.
activation energy ferrous-iron oxidation Leptospirillum ferriphilum packed-bed bioreactor
F. Chowdhury TV Ojumu
Department of Chemical Engineering,Cape Peninsula University of Technology, P. O Box 652,Cape Town 8000, South Africa
国际会议
The 19th International Biohydrometallurgy Symposium(第19届国际生物湿法冶金大会 IBS2011)
长沙
英文
101-105
2011-09-18（万方平台首次上网日期，不代表论文的发表时间）