Organoarsenic resistance and bioremoval of Acidithiobacillus ferrooxidans.

The tolerance and bioremoval of dimethylarsinic acid (DMA(V)) by Acidithiobacillus ferrooxidans (A. ferrooxidans) were investigated here. The inhibitory concentration (IC) of DMA(V) was determined for A. ferrooxidans. The effects of various parameters such as pH, contact time, initial DMA(V) concentration, biosorbent dose and temperature were systematically examined to study the biosorption processes. Results indicated that Langmuir model fitted better than Freundlich model to the equilibrium data. Analysis of kinetic data showed that the biosorption processes of DMA(V) involved pseudo-second-order kinetics. Thermodynamic analysis showed that the biosorption of DMA(V) onto A. ferrooxidans was feasible, spontaneous, endothermic and chemisorptive under examined conditions. Fourier transform infrared spectroscopy (FTIR) showed the involvement of -OH, -NH and -SO(3) groups in the biosorption process.