Kinetics and thermodynamics of lead ion sorption on palm kernel fibre from aqueous solution

The kinetics and thermodynamics of lead ions sorption from aqueous solution on palm kernel fibre have been investigated. The experimental data was analyzed by Langmuir, Freundlich and Redlich-Peterson isotherms using linear coefficient of determination and the non-linear Chi-square test. The equilibrium sorption capacity of lead ions was determined from the Langmuir equation and found to be 49.9 mg/g at 65°C. A batch sorption model, based on the assumption of the pseudo-second-order mechanism, was applied to predict the rate constant of sorption, the equilibrium sorption capacity and the initial sorption rate with the effect of temperature. An activation energy of sorption was evaluated as 13.5 kJ/mol for the sorption of lead ions on palm kernel fibre. Various thermodynamic parameters, ΔH°, ΔS° and ΔG°, were computed from equilibrium constant values. The results show that the sorption of the lead ions on palm kernel fibre is a spontaneous and endothermic nature process. © 2005 Elsevier Ltd. All rights reserved.