Nano-sulphonated poly (glycidyl methacrylate) cations exchanger for cadmium ions removal: Effects of operating parameters

Nano-poly (glycidyl methacrylate) cation exchange resin with sulphonate functionality content ranging from 1.77 to 4.00 (mmol/g) was prepared and examined in removal of cadmium ions from synthetic cadmium solution. Initial fast adsorption step was recognized at 15 min where 90% of cadmium ions were adsorbed while equilibrium was reached within two hours. The equilibrium adsorption capacities ranged from 9.947 to 480 mg/g of polymer as initial cadmium concentration increased from 100 to 5000 ppm. The adsorption experiments for Cd2+ were conducted at various operating conditions. It was concluded that the sorption was considerably affected by initial cadmium concentration, solution pH and resin dose. Nevertheless, there was slight dependence of sorption on agitation speed, solution temperature and the sulphonation degree. The order of kinetic reaction was found to follow closely the second-order kinetic model and ion exchange mechanism played a significant role in all studied cadmium sorption systems. Moreover, the obtained results indicate that film diffusion governs the rate limiting process. (C) 2011 Elsevier B.V. All rights reserved.