Biosorption of lead, cadmium and mercury by immobilized Microcystis aeruginosa in a column

Abstract

Immobilized Microcystis aeruginosa in a flow-through sorption column was evaluated for the potential to remove Pb2+, Cd2+ and Hg2+ from aqueous solutions. M. aeruginosa showed high affinity for the three heavy metals with removal efficiency of 90% for Cd2+ and Hg2+, and 80% for Pb2+ at saturation conditions. Competitive sorption experiments conducted in paired and ternary systems indicated that Pb2+ was sequestered preferentially over Cd2+ and Hg2+. The presence of Cd2+ interfered only slightly with the uptake of Hg2+, as Pb2+ and Hg2+ did with Cd2+. In contrast, Hg2+ sorption was affected by Pb2+ to a great extent. Desorption with 1M HCl was completed within 25min with high efficiency and effectiveness for the three metals. The results of this study indicate that M. aeruginosa is to be a potential biosorbent material except when Hg2+ and Pb2+ are in the same contaminated solution.