Novel heterogeneous cellulose-based ion-exchange membranes for electrodialysis

Heterogeneous membranes are generally prepared by mixing ion-exchange (IE) resins, whether cation or anion resins, with a polymer matrix, in which the resin is well embedded within the polymer in a homogeneous manner. In the present paper, novel membranes were fabricated and different variables were investigated, such as types of polymer matrix whether cellulose acetate (CA) or cellulose acetate butyrate (CAB), source (properties) of CA, de-esterified membranes, type of IE resins (cationic, anionic, or nonionic), and ground or pristine resins. It was found that ground resins gave thinner membranes with better perm-selectivity for both cationic and anionic IE resins with the two brands of CA tested. The nonionic IE resin gave adverse results as expected, especially when it was pulverized before mixing with the polymers. CAB gave unfavorable results compared with the two types of CA polymers studied and gave lower perm-selectivity especially when the IE resins were ground before mixing to the CAB polymer.