Removal of Cu (II) from aqueous solutions by Calabrian pine bark wastes

In this study the sorption capacity of the Calabrian pine bark wastes (Pinus brutia Ten) to remove Cu (II) ions from aqueous solutions was tested as function of experimental parameters, such as contact time, initial solution concentration, solution pH and solution temperature. Adsorption of copper ions on the bark wastes was so brisk that within 10 min approximately 60-71% of Cu (II) ions could be removed. The amount of Cu (II) adsorbed increased with increasing initial solution concentration and pH, however, it varied partially with temperature. Experimental data showed that adsorption isotherm followed the Freundlich model, and isotherm parameters were calculated at different temperatures. Kinetic studies revealed that adsorption process followed the intra-particle diffusion kinetic. From the rate constants of intra-particle diffusion kinetics at various temperatures, it could be deduced that boundary layer thickness decreased with increasing, temperature. The activation energy of adsorption was -10.43 k J mol(-1). Moreover, the thermodynamic parameters, standard free energy (DeltaG), standard enthalpy (DeltaH) and standard entropy (DeltaS), of the adsorption process were calculated. The results from experimental data indicated that adsorption process was of exothermic nature.