ION-EXCHANGE FIBERS: PREPARATION AND APPLICATIONS.

This paper describes the recent application of ion exchange fiber in a new electrodialysis stack configuration which was recently proposed by Kedem. This assumes the availability of woven spacers made of ion-exchange fibers, both cation- and anion-exchangers. Ion-exchange fibers are characterized by large exchange surface low flow resistance, and ease of handling. A new brand of ion-exchangers from low-density melt-spun polyethylene fibers was recently prepared. This method is based on the de Korosy-Shorr patent but utilizes the special geometry of the fibers and is tailored to achieve high mechanical strength and optimal radial distribution of ion-exchange sites. The fiber thus obtained has an average ion-exchange capacity of 1. 6 meg/g dry weight, electrical conductivity of the order of 100 OMEGA -cm (better than the conductivity of ion-exchange material), and fairly high mechanical strength.