Ion-exchange membranes for metal ions separation

A new synthetic membrane has been synthesized by direct radiation grafting of acrylonitrile and vinyl acetate in a binary monomers mixture onto low density polyethylene and isotactic polypropylene films. The effect of grafting conditions, such as comonomer composition and concentration on the grafting process, was determined. The graft copolymers, thus obtained, have been chemically treated to improve their ion-exchange and hydrophilic properties. To explore the applicability of the prepared membranes. their sorption capacity and selectivity towards different metal ions such as Cu, Co. Fe, Pb, Sr, Cd and Li were investigated. The degree of grafting had a considerable influence on the metal uptake of these membranes and it increased with graft yield. The prepared membranes have great affinity toward Fe3+ if compared with other metal ions investigated. For a mixture of metal ions such as Cu2+, Sr2+ and Pb2+ these membranes show ability to chelate these ions from their mixtures in the order of Cu2+ > Sr2+ > Pb2+. But for a mixture of Co2+, Cd2+ and Li+ the selectivity was in the order of Co2+ > Cd2+ >Li+.