Sorption kinetics for the removal of copper and zinc from effluents using bone char

The removal of copper and zinc ions from aqueous effluents by bone char has been studied in single component sorption systems. The sorption capacity of bone char for copper and zinc is 0.75 and 0.53 mmol per g bone char, respectively. The values indicate that bone char is a suitable sorbent for the two metal ions. The equilibrium isotherms are best described by a Langmuir-Freundlich (L-F) type isotherm equation. The kinetics of sorption of the two metal ions have been analyzed by two kinetic models, namely, the Lagergren pseudo first-order model and the Elovich kinetic model. Kinetic analysis of the two models has been carried out for system variables - initial metal ion concentration and mass of bone char. The rate constants for the two models have been determined and the correlation coefficients have been calculated in order to assess which model provides the best fit predicted data with experimental results. The Elovich equation provides the best fit to experimental data. (C) 2000 Elsevier Science B.V. All rights reserved.