Characterization of anion exchange membrane modified by electrodeposition of polyelectrolyte containing different functional groups

In the paper a homogeneous anion exchange membrane was modified by electrodeposition of the polyelectrolyte containing different functional groups such as poly(sodium 4-styrene sulfonate) (PSS), poly(vinylsulfonic acid, sodium salt) (PVS) and poly(sodium acrylate) (PAAS), respectively, to improve its antifouling performance in electrodialysis. The surface morphology and electrical resistance of modified membranes were nearly no obvious changes, but their contact angles all increased by 10°. The zeta potential results indicated that the polyelectrolyte PVS with sulfonic group but without benzene ring was more favorable to increase the negative charge density of modified membrane. After fouling experiments for sodium dodecylbenzene sulfonate (SDBS), the contact angle and SEM analyses indicated that the antifouling performance of all the modified membranes was significantly enhanced; moreover, PVS was the most suitable for improving the antifouling performance of anion exchange membrane among the polyelectrolytes. The effect of various functional groups contained in different polyelectrolytes on the antifouling performance of modified membranes was analyzed further to reveal the antifouling mechanism of modified membranes for SDBS. It was also confirmed that the negative effect of the polyelectrolyte layer electrodeposited on the membrane surface on electrodialysis performance could be ignored by measuring the conductivity change of the dilute solution.