Determination of the optimal conditions for the adsorption of cadmium ions and phenol on chestnut (Castanea sativa) shell

Abstract

Adsorption of cadmium ions and phenol from aqueous solutions on chestnut (Castanea sativa) shell was studied. An incomplete 33 factorial design was applied to investigate the influence of the initial cadmium ions (20-60-100 mg l-1) or phenol concentration (0.01-0.255- 0.5 g l-1), temperature (10-25-40°C for cadmium and 10-35-60°C for phenol) and pH (5.5-7.0- 8.5 for Cd2+ ions and 2.5-6.0-9.5 for phenol) on the amount of contaminant adsorbed and on the adsorption percentage. Statistical analysis of the results showed the significance of the individual factors and their interactions on both adsorption processes. The best conditions for high cadmium ions and phenol removal within the experimental ranges of the variables studied were the natural pH (around 5.5) and a temperature of 25°C for cadmium ions and 60°C for phenol. Under these conditions, adsorption equilibrium was modelled by the Freundlich isotherm for cadmium ions and by the Langmuir isotherm for phenol. © 2009 Global NEST.