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

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 1 M HCl was completed within 25 min 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.