Mitigation of an anion exchange membrane fouling by coupling electrodialysis to anodic oxidation

Abstract

Membrane fouling reduces the performance of membrane processes. In this work, a coupling between anodic oxidation and electrodialysis was designed and studied to prevent and control fouling of the AMX anion exchange membrane during the electrodialysis process. Analysis of the AMX membrane surface by SEM, EDS and ATR-FTIR revealed that the presence of sodium dodecyl benzene sulphonate in the solution led to membrane fouling. The fouling resulted in an increase in the membrane electrical resistance and a decrease in the chloride ion transfer flux through the membrane. It was shown that the combination of anodic oxidation with electrodialysis not only greatly reduces the fouling of the AMX membrane but also removes a persistent organic pollutant present in the effluent to be treated. Furthermore, the study of the effect of certain operating parameters on the membrane fouling and the mineralization of the solution has shown that the increase in the current density of the anodic oxidation leads to a decrease in the membrane electrical resistance and an improvement in the efficiency of mineralization. On the other hand, the application of a current density of 40 mA cm−2, natural pH and Na2SO4 as electrolyte supporting during 120 min of eletrodialysis led to an increase in the electrical resistance of the membrane of only 1.23 times and a strong mineralization of the solution (96 %).