PROCESS FOR PRODUCING A BIPOLAR MEMBRANE AND PROCESS FOR PREPARING AQUEOUS SOLUTION OF ALKALI METAL HYDROXIDE BY ELECTRODIALYSIS

摘要

PCT No. PCT/EP95/03596 Sec. 371 Date Jun. 10, 1997 Sec. 102(e) Date Jun. 10, 1997 PCT Filed Sep. 12, 1995 PCT Pub. No. WO96/09337 PCT Pub. Date Mar. 28, 1996Process for the manufacture of a bipolar membrane, according to which an anionic membrane is joined side by side to a cationic membrane, the membranes having been subjected beforehand to a conditioning pretreatment, the conditioning pretreatment of the anionic membrane comprising bringing the latter into contact with a compound of a polyvalent metal and with an aqueous alkali metal hydroxide solution and the conditioning pretreatment of the cationic membrane essentially comprising bringing the said cationic membrane into contact with water which is essentially free from polyvalent metal and from alkali metal. Use of the bipolar membrane thus obtained for the manufacture of aqueous sodium hydroxide solutions by electrodialysis.