ANALYSIS OF FACTORS LIMITING THE USE OF BIPOLAR MEMBRANES - A SIMPLIFIED MODEL TO DETERMINE TRENDS

The influence of factors limiting both the purity and the concentratio n levels of HCl and NaOH produced by electrodialysis of NaCl with bipo lar membranes is analysed. The bipolar membrane is the WSI membrane se t up by Simons. Co-ion leakages through homopolar and bipolar membrane s an measured under different experimental conditions. The co-ion leak ages through the homopolar membranes lead to acid and base containing between 1 and 4% weight of salt. The co-ion leakages through homopolar membranes limit the concentration of the products. A theoretical calc ulation of both the concentrations of the produced acid and base, and also their degree of purity is achieved. This model allows the predict ion of the level of concentration of the products as a function of the water transport, the co-ion leakages through homopolar membranes and the current density.