Fouling of an anion exchange membrane in the electrodialysis desalination process in the presence of organic foulants

Interest in desalination using membrane processes has increased with the growth of membrane science and technology. Fouling of ion exchange membranes is one of the most significant considerations in the operation of the electrodialysis desalination process. The influence of the adsorption capacity of foulants on the fouling potential was investigated in an electrodialysis desalination process in the presence of negatively charged organic foulants, humate, bovine serum albumin and sodium dodecylbenzenesulfonate (SDBS). The SDBS showed higher adsorption capacity on the anion exchange membrane surface than the other two foulants in the adsorption equilibrium experiments. Of three different organic foulants, the SDBS had a more severe fouling effect on the process performance in the electrodialysis desalination of synthetic brackish water, with irreversible fouling due to the high adsorption capacity. The study clearly showed that the adsorption capacity affects the fouling potential of the electrodialysis desalination process.

In this study the fouling potential of the AMX membrane was analyzed in the electrodialysis desalination of synthetic brackish water in the presence of three organic foulants (humate, BSA, and SDBS). The fouling potential was predicted through the characterization of physical and electrochemical properties and the adsorption experiments. Three foulants were highly negatively charged according to the zeta potential measurements, implying that they can foul anion exchange membranes. In the adsorption of organic foulants, the SDBS showed a higher adsorption capacity on the AMX membrane surface than the other foulants. SDBS had greater fouling effects on the membrane in electrodialysis desalination, which is related to the high adsorption capacity. The SDBS fouling system showed the largest decrease in the current efficiency and the largest increase in the power consumption after fouling, producing more irreversible fouling on the system. This study shows that a foulant with a high adsorption capacity signicantly affects the electrodialysis desalination process performance with irreversible fouling.