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The removal of chromium, a highly toxic metal causing environmental pollution from dilute aqueous solution, was studied in the present work using growing and washed cells of a mutant strain of Bacillus cereus (M116) isolated from tannery waste. Particularly, the effects of pH, temperature, metal ion concentration and contact time on removal of chromium werestudied. About 40% chromium removal, was observed by growing cells of the selected strain at pH 6.5, temperature 30o±1oC, inoculum size 3%, medium volume 50 ml/250 ml Erlenmeyer flask, and initial chromium concentration 50 ppm. Usingresting cells 98.02% and 78.34% chromium removal was possible with initial chromium concentration of 25 and 50 ppm, respectively, at pH 3.0, temperature 25-35oC and 2.73 g/L biomass concentration. It was found that the overall adsorption process was best described by pseudo-second order kinetics. Freundlich and Langmuir adsorption models were found suitablefor describing the short-term biosorption of chromium (VI). IR spectral analysis of the biomass was carried out to find out the functional groups responsible for chromium (VI) biosorption.
lead biosorption, immobilization, pseudo second order, Freundlich isotherm