Biosorption of Copper (II) from Aqueous Solution by Saccharomyces cerevisiae : Kinetics and Thermodynamics

Biosorption equilibrium, kinetics, and thermodynamics of Cu ions onto S. cerevisiae were studied in a batch system with respect to temperature and initial ion concentration. Biosorption efficiency increased up to Cu ion initial concentration of 75 mg/L, and then decreased with the increasing metal ion concentration. Equilibrium uptake value changed from 9.8 mg/g at 20° C to 14.5 mg/g at 50° C. Langmuir isotherm model was found to be in good correlation with data.. Biosorption enthalpy indicated that the biosorption process has an endothermic nature. Pseudo first order, pseudo second order and intraparticle diffusion models were applied to the experimental data. High value of correlation coefficients ( 0.99) and the comparison of the experimental equilibrium concentration of copper with value calculated from the kinetic model indicated that the Cu(II) uptake by S. cerevisiae was best described by pseudo second order rate model. The thermodynamic constants of biosorption namely, ΔG°, ΔH° and ΔS° were also evaluated.