PRECONCENTRATION OF TRACE-METALS USING SILICA-IMMOBILIZED ALGAE CELLS IN A CHROMATOGRAPHIC-SEPARATION PROCEDURE

The utility of silica-immobilized algae to separate and preconcentrate trace amounts of Pb, Cu, Zn and Cd was evaluated in several different solution environments including mixed metal solutions, simulated riverine water, brine and simulated seawater solutions. Results of the preconcentration experiments showed excellent quantitative recoveries for Cu in all solution matrices studied. Pb was efficiently extracted from all solutions except the brine and seawater solutions. Cd and Zn were weakly bound to the resin and exhibited efficient uptake only in the multimetal matrix and in the solutions that contained less than 400 mg l-1 of either Na+ or K+. Equilibrium constants governing the algae-metal reaction were calculated from adsorption profiles and a selectivity series of the resin determined. The algae-metal bond strengths decreased in the order Pb>Cu>Cd>Zn>Ca>Mg much greater than Na,K. These results were obtained in an acetate matrix. When Cl- was the major anion present, Cu was more strongly retained on the algae than Pb. The chlorides likely mask the Pb causing a decrease in the adsorption efficiency or chloro-Cu species may contribute to the overall Cu adsorption.