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

A process for producing a bipolar membrane is described in which a cationic membrane undergoes a treatment with a salt from a group 8 metal, an anionic membrane undergoes a treatment with a salt of a transition metal not belonging to group 8, and then the two membranes are conjoined and, before and/or after having been conjoined, the membranes are brought into contact with a treatment solution selected from alkaline aqueous solutions, aqueous metal sulphate solutions and aqueous metal sulphite solutions.