Desalination by electrodialysis with the ion-exchange membrane prepared by radiation-induced graft polymerization

Ion-exchange membranes modified with the triethylamine [-N(CH2CH3)(3)] and phosphoric acid (-PO3H) groups were prepared by radiation-induced grafting of glycidyl methacrylate (GMA) onto rhc polyolefin nonwavon fabric (PNF) and subsequent chemical modification of poly(GMA) graft chains. The physical and chemical properties of the GMA-grafted PNF and the PNF modified with ion-exchange groups M ere investigated he SEM, XPS, TGA, and DSC. Furthermore, electrochemical properties such as specific electric resistance. transport number of K+, and desalination were examined. The grafting yield increased with increasing reaction time and reaction temperature. The maximum grafting yield was obtained with 40% (vol.%) monomer concentration in dioxane at 60 degreesC. The content of the cation-and anion-exchange group increased with increasing grafting yield. Electrical resistance of the PNF modified with TEA and -PO3 H group decreased, while the water uptake (%) increased with increasing ion-exchange group capacities. Transport number of the PNF modified with ion-exchange group were the range of ca. 0.82-0.92. The graft-type ion-exchange membranes prepared by radiation-induced graft copolymerization were successfully applied as separators for electrodialysis. (C) 2001 Elsevier Science Ltd. All rights reserved.