A chelating microporous membrane was prepared by grafting of an epoxy-group-containing vinyl monomer onto a microfiltration membrane by applying radiation-induced graft polymerization and subsequent modification with ethylenediamine (EDA). The resultant membrane had an immobilized EDA density of 0.67 mol/kg while maintaining the permeability of the starting membrane. Permeation of palladium solution (20 g-Pd/m3, pH=0.5-4) through the chelating microporous membrane minimized the diffusional path of the palladium ion to the immobilized EDA. Molar ratio of the Pd sorbed to the immobilized EDA was 0.36 at pH=1.
