Biosorption of cadmium(II) and lead(II) from aqueous solutions using Pleurotus ostreatus immobilized on bentonite

Abstract

The purpose of this work was to evaluate the potential of a white rot fungi (P. ostreatus) immobilized on bentonite, in a continuous flow removal of trace heavy metals. The procedure is based on the biosorption of Cd(II) and Pb(II) ions on a column of bentonite loaded with dried, dead fungi components prior to their determination by atomic absorption spectroscopy (AAS). Cd(II) and Pb(II) were determined with a relative error of less than 5%. Various parameters such as pH, amount of adsorbent, eluent type and volume, flow rate of the solution and matrix interference effect on the retention of the metal ions were investigated. This procedure was applied to Cd(II) and Pb(II) determination in aqueous solutions, including tap water system. The optimum experimental parameters were determined to be pH 5, concentration of 10mg/L, contact time of 30min and 0.2g of adsorbent for a quantitative adsorption of the metals. The optimum flow rate was found to be 2.5mL/min for all metal ions. Each column can be used up to 20 successive analyses without considerable change in recoveries of metal ions.The proposed method is excellent as regards simplicity, sensitivity, selectivity, precision, accuracy and column stability.