Organoarsenic resistance and bioremoval of Acidithiobacillus ferrooxidans

The tolerance and bioremoval of dimethylarsinic acid (DMAV) by Acidithiobacillus ferrooxidans (A. ferrooxidans) were investigated here. The inhibitory concentration (IC) of DMAV was determined for A. ferrooxidans. The effects of various parameters such as pH, contact time, initial DMAV 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 DMAV involved pseudo-second-order kinetics. Thermodynamic analysis showed that the biosorption of DMAV onto A. ferrooxidans was feasible, spontaneous, endothermic and chemisorptive under examined conditions. Fourier transform infrared spectroscopy (FTIR) showed the involvement of –OH, –NH and –SO3 groups in the biosorption process.