Biosorption potential of the macrofungus Ganoderma carnosum for removal of lead(II) ions from aqueous solutions

This paper reports the utilization of a macro-fungus Ganoderma carnosum as a biosorbent material for the removal of lead( II) ions from aqueous solutions. The biosorption potential of G. carnosum was investigated by batch experiments. The influences of physico-chemical parameters like pH, biosorbent dosage, contact time and initial metal ion concentration were evaluated. The biosorption equilibrium was attained in 10 minutes. Equilibrium biosorption data were analyzed by the Freundlich, Langmuir and Dubinin-Radushkevich ( D-R) isotherm models. Maximum biosorption capacity of biosorbent was found to be 22.79 mg g(-1) (1.10 x 10(-4) mol g(-1)) at the pH value of 5.0. The biosorbent was regenerated using 10 mM HCl solution, with up to 96% recovery, and reused four times in biosorption-desorption cycles successively. Biosorption efficiency of G. carnosum was also examined in a real effluent. The mechanism of the biosorption was investigated with FTIR, SEM and EDAX analysis and the findings suggested that the biosorption process involved in ion exchange as dominant mechanism as well as complexation. The ion exchange mechanism was also confirmed by the mean free energy value obtained from D-R isotherm model.