Removal of Cu2+, Cd2+ and Ni2+ ions from aqueous solution using a novel chitosan/polyvinyl alcohol adsorptive membrane

The chitosan/poly vinyl alcohol membrane was modified by addition of some amine group to the membrane structure utilizing polyethyleneimine (PEI) in order to increase ionic metals adsorbent properties of the membrane. The removal percentage of the modified membranes was compared with the pristine membrane and activated carbon as common adsorbents. The membranes were characterized by FTIR, SEM, swelling degree and porosity measurement. The removal percentage of the membrane containing 0.5 wt.% PEI was more than 60% higher than the activated carbon and more than 40% higher than the pristine membrane. The modified membrane showed excellent adsorption capacity of 112.13, 86.08, and 75.5 mg/g for Cd2+, Cu2+ and Ni2+, respectively at 25 degrees C and pH 6. Adsorption kinetics and equilibrium adsorption isotherm fitted pseudo-second-order kinetic model and Langmuir isotherm model well, respectively. The membrane could be regenerated successfully in Na(2)EDTA aqueous solution with no significant reduction in its adsorption efficiency.