Preparation of bipolar membrane for use in electrodialysis involves joining cationic and anionic membranes pretreated with different metal salts, and with aqueous alkaline or metallic sulfate or sulfite solution

摘要

Preparation of bipolar membrane comprises treatment of cationic membrane with salt of metal from VIII group of Periodic System; treatment of anionic membrane with salt of transition metal from different group, and joining the membranes, treated before and/or after being joined, with solution selected from aqueous alkaline, metal sulfate and metal sulfite solution. An Independent claim is also included for use of the bipolar membrane in the production of sodium hydroxide by electrodialysis of an aqueous solution of sodium salt, preferably sodium chloride.