Comparative Assessment of Heavy Metal Removal by Immobilized and Dead Bacterial Cells: A Biosorption Approach

Microorganisms play a vital role in heavy metal contaminated soil and wastewater by the mechanisms of biosorption. In this study, heavy metal resistant bacteria were isolated from the effluent samples of an electroplating industry and the biosorption of copper (Cu), cadmium (Cd) and lead (Pb). These isolates were characterized to evaluate their applicability for heavy metal removal from industrial wastewaters. Initially the samples physico-chemical parameters were analyzed. The optimum conditions of pH, biomass concentration and heavy metal concentration were determined for the microbial growth on biosorbents and correlated with heavy metal removal. The observed optimum conditions were applied for the biosorption process carried out in dried biomass and immobilized bacterial isolates. The biosorption capacity of immobilized bacterial isolates like Bacillus sp., Pseudomonas sp. and Micrococcus sp. were 69.34, 90.41 and 84.27% of Cu, Cd and Pb respectively. But the dried biomass of the same species adsorbed only 44.73, 86.66 and 79.22% of Cu, Cd and Pb respectively. Experimental results reveal that all the immobilized strains have potential application for the removal of Cu, Cd and Pb from industrial wastewater than the dried biomass.