A hydrophilic amphoteric nanofiltration membrane was prepared by UV irradiation successive graft polymerization of diallyldimethylammonium chloride (DADMAC) and sodium styrenesulfonate (SSS) onto the surface of ultrafiltration membranes made of polyetherketone cardo (PEK-C). The effect of monomer concentration in solution and grafting time on the membrane performances was studied by measuring pure water flux and salt retention through the membrane. The results showed that the membrane performances of the amphoteric nanofiltration membrane were related to the monomer concentration in solution and the grafting time of the two monomers. The membrane has high retention to salts composed of high valent co-ions and counter-ions.

Key words: UV irradiation, polyetherketone-cardro, amphoteric nanofiltration membrane, diallyldimethylammonium chloride, sodium styrenesulfonate