Improved anti-organic fouling of polyvinyl chloride-based heterogeneous anion-exchange membrane modified by hydrophilic additives

Abstract

Organic fouling – which generally gives a more severe effect on anion-exchange membranes (AEMs) – leads to performance degradation of electro-membrane processes. In this work, polyvinyl chloride (PVC)-based AEM was prepared by a solution casting method. Three AEMs were modified by different hydrophilic additives, namely polyethylene glycol 400 (PEG400), polyethylene glycol 1000 (PEG1000), and ZnO nanoparticles (M2-M4 membranes). Then, the properties of these modified membranes were compared to the pristine membrane (M1 membrane). The effect of hydrophilic additives on the anti-organic fouling properties of modified membranes was investigated during a simple electrodialysis test of feed water containing humic substances. The results of chemical structure analysis show that the additives are successfully incorporated in the membrane matrix. The presence of the hydrophilic additive in the membrane matrix increases membrane conductivity. The highest increase in conductivity is obtained by the addition of PEG400 (up to 50 %). Meanwhile, water uptake, ion-exchange capacity, and water contact angle of the modified membranes are insignificantly changed. In addition, the additives can improve membrane resistance toward organic fouling. The introduction of additive can suppress the increasing rate of membrane areal resistance by ∼60 %.