Surface modification of anion-exchange electrodialysis membranes to enhance anti-fouling characteristics

During electrodialysis of aqueous solutions, anion-exchange membranes are fouled by organics present in the water. Increasing the fouling resistance of styrene divinyl benzene based membranes by modifying them with high molecular mass surfactants was investigated. After modification of the membrane with surfactants A-3 and NB-8 under static conditions, the fouling resistance was evaluated in the presence of humic acid (HA) and dodecylbenzenesulphonate (DBS). Modification of IONICS anion-exchange membranes with A-3 agent allowed for stable operation in a solution of 0.05 N Na2SO4 and 30 mg.l-1 HA. With 30 mg.l-1 DBS, no membrane fouling occurred. Modification of IONICS membranes with NB-8 agent permitted electrodialysis of solutions containing 100 and 60 mg.l-1 of DBS and HA respectively, at current densities below the limiting value.