Cation exchange membrane integrated with cationic and anionic layers for selective ion separation via electrodialysis

The advances of electrodialysis (ED) have been restricted by the trade-off between perm-selectivity and ion flux of ion exchange membranes. This article lucidly explains the fabrication of novel PVA-based hybrid membranes modified with cationic and anionic layers. Cationic layer is composed of quaternized poly (2, 6-dimethyl-1, 4-phenylene oxide), while anionic layer is sulfonated poly (2, 6-dimethyl-1, 4-phenylene oxide). Interestingly, the perm-selectivity of Li+/Mg2+ via ED was observed up to 5.16 with a feed concentration of 0.1 mol L−1 LiCl/MgCl2 at 2.12 mA cm−2 current density. Electrochemical impedance spectroscopy was used to get further insight about the membrane and solution interfaces such as the influence of a base membrane and the deposited layers, which showed the perm-selective behavior of the modified membranes. The observed high perm-selectivity of modified membranes will step forward the ED applications for production of salts and treatment of saline water comprising monovalent and divalent cations.