Bipolar membrane, process of its manufacture and use

摘要

In the present invention there is disclosed a bipolar membrane that is usable for electrodialysis of aqueous electrolytes and consisting of two ion-exchange membranes, i.e. anion-exchange and cation-exchange membranes, which are connected with each other through the mediation of a joint contact surface. The invented membrane contains on the joint contact surface a gel of hydrated metal sulfate and/or sulfite, whereby if it contain indium, cerium, manganese or copper sulfate the content of these sulfates is less than 0.01 percent by weight. The manufacturing process of such bipolar membrane is characterized in that the ion-exchange membranes are treated with an aqueous solution of metal cations and/or sulfite anions under formation of a precipitate of metal sulfate and/or sulfite, whereby this precipitate is converted after coupling of both the anion-exchange and the cation-exchange membranes to a gel on at least a portion of their joint contact surface.