Kinetics and thermodynamics study of lead adsorption on to activated carbons from coconut and seed hull of the palm tree

The kinetic and thermodynamic of the bath sorption of lead (Pb) on to activated carbon from Coconut (CA) and Seed hull of the Palm tree (GA) have been investigated. The effects of initial Pb concentration, contact time and temperature were examined. The results showed that the adsorption capacities of the activated carbons increased with the initial lead concentration. The process sorption followed a pseudo first order kinetics and parameters such as Ea and k0 were determined. It could be best fitted by the Langmuir and Freundlich isotherms. From the first, the equilibrium sorption capacities of lead ion were determined and found to be respectively 4.38 and 3.77 mg/ g for CA and GA at 60 °C. The thermodynamic parameters such as ΔH, ΔS and ΔG were computed from the experimental data. These values show that the adsorption is endothermic and non spontaneous. Moreover, the relative weak values of ΔH (∼5 kcal/mol) confirm a physical adsorption. The maximum adsorptions were obtained at 60 °C, pH 4 and with a Pb initial concentration of 100 mg/L. © Winter 2007, IRSEN, CEERS, IAU.