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

Palm kernel fibre is produced as a waste during palm kernel oil production, with approx. 15 600 tonnes of shell and fibre wastes generated annually. The potential for reuse of this waste as a sorption material was investigated by measuring Pb uptake from aqueous solutions as a function of temp. Experimental data were analysed using the Langmuir, Freundlich and Redlich-Peterson isotherms. An equilibruim sorption capacity of 49.9 mg/g at 65°C was calculated using the Langmuir equation. Additional process modelling was undertaken, based on a pseudo-second-order reaction mechanism, and allowed the calculation of an initial rate of sorption, an equilibrium sorption capacity and a rate constant for sorption for a batch sorption model. Process thermodynamics were also determined, and suggested that Pb sorption on palm kernel fibre is spontaneous and endothermic in nature.