Equilibrium, Thermodynamic, and Kinetic Studies on Lead (II) Biosorption from Aqueous Solution by Saccharomyces cerevisiae Biomass

Abstract

This paper presents a biosorption procedure for the preconcentration of Pb2+ ions using Saccharomyces cerevisiae biomass. The influence of several factors including pH, biomass dosage, contact time, and temperature on biosorption efficiency were optimized. At optimum value of all the equilibrium, thermodynamic, and kinetic parameters of Pb2+ ion biosorption was investigated by testing the Langmuir and Freundlich models and first and second order kinetic models were applied. The biosorption capacity of S. cerevisiae biomass was determined 89.6 mg/g, while the retained Pb2+ ions by S. cerevisiae were reversibly eluted using 5 mol/L HNO3. Due to the high stability of S. cerevisiae the applied biomass can be used successively ten times with a slightly decrease (about 20%) in the recovery of Pb2+ ions. The calculated thermodynamic parameters, δG°, δH°, and δS° showed that the biosorption of Pb2+ ion onto S. cerevisiae biomass was feasible, spontaneous, and endothermic under examined conditions. The results of kinetic analysis showed that the biosorption processes of Pb2+ ions onto S. cerevisiae biomass followed pseudo second order kinetics. A simple and economic biosorption procedure using Saccharomyces cerevisiae biomass for preconcentrating Pb2+ ions is presented here. The results indicate a pseudo-second-order kinetic mechanism. The biosorption mechanism was evaluated by FTIR analysis. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.