Preparation and performance of bipolar membranes with liquid ion-exchange medium

The current density is rather low in solid bipolar membranes, because the water transfer r ate is relatively slow across solid bipolar membranes made of solid ion-exchange materials. This paper describes the use of pdymer solutions, such as phosphatic pdy(vinyl alcohd) sdution, poly(acrylic acid) solution and pdy(vinyl alcohol) solutions with dispersed cation/anion-exchange resin particles to prepare bipolar membranes. The 0.1 mol/L NaOH and the 0.05 mdlL H
2
S0
4
were used to test the performance of the bipolar membranes. For a fixed liquid layer thickness, both the current density and the selectivity ircrease with the concentration increase of a polyelectrolyte solution. The maximum current density measured in the experiment was 1497 A/m
2
with a selectivity of 96.8%.