Adsorption, desorption, and kinetic study on Cr(III) removal from aqueous solution using Bacillus subtilis biomass

Discharge of untreated industrial effluents containing heavy metals is hazardous to the environment as they are highly toxic and accumulates throughout the food chain. This study reports the removal of trivalent chromium from aqueous solution using Bacillus subtilis biomass, best suited for the treatment of real tannery effluents since Cr(III) salt is used for tanning. The optimum pH and temperature for biosorption was found to be 4.0 and 60A degrees C, respectively. A biosorbent dosage of 1 g l(-1) showed maximum metal uptake (q (e) ) of 23.9 mg g(-1) for an initial metal concentration of 100 ppm. Pseudo-second-order kinetics best describes the adsorption process. Best fit for adsorption was obtained with Freundlich model. Desorption experiments with 5 M NaOH, inferred the reusability of the biomass. Fourier transform-infrared spectroscopy was used to study the mechanism of metal binding.