Preparation of Ion-Exchange Membranes Applicable to Electrodialysis Using Commercially Available Polymeric Films

Abstract

The improvement of ion-exchange membranes used for the electrodialysis of seawater is demanded to reduce the production cost of salt. Instead of the conventional paste method, the electron-beam-induced graft polymerization was proposed as a novel method for the preparation of the ion-exchange membranes using commercially available polymeric films as a starting material. The resultant ion-exchange membranes based on high-density polyethylene and 6-nylon films exhibited a higher performance in electrodialysis of a model seawater than the currently-used ionexchange membranes. Polymeric structure such as crystallite size and spacing during grafting and subsequent chemical modifications was characterized by X-ray diffraction, small-angle X-ray scattering, and small-angle neutron scattering. The channel for the transport of ions through the membranes is discussed.