METHOD FOR ELECTRODIALYSIS AND HETEROGENEOUS ION-EXCHANGE MEMBRANE

摘要

PROBLEM TO BE SOLVED: To efficiently remove polyvalent cations, boric acid ion, etc., from a soln. wherein a various kinds of salts coexist by using an ion-exchange membrane with a chelate-formable functional group as a membrane and making a difference in pH between a soln. in a concn. room and a soln. in a dilution room. ;SOLUTION: An electrodialysis apparatus is prepd. by using an ion exchange membrane with a functional group which can form a chelate bonding with an ion, namely, a chelate-formable functional group having a lone pair contg. an element selected from N, S, O and P. In addition, in this method for electrodialysis, a difference in pH between a soln. in a concn. room and pH of a soln. in a dilution room is given so as to facilitate dissociation of an ion forming a chelate bonding with the chelate-formable functional group. Polyvalent cations and boric acid ion are easily and efficiently removed thereby in a purification process of a water soln.;COPYRIGHT: (C)1997,JPO