Hydrogen bonding promoted electrodialysis performance of a novel blend anion exchange membrane

Abstract

In order to improve the performance of electrodialysis enabled desalination, a simple, efficient and low-cost method for the preparation of high-performance anion exchange membranes (AEM) is required. In this work, we designed a novel hydroxyl quaternized polysulfone (HQPSf) and blended it with environmentally friendly chitosan (CS) for AEM fabrication. Our results demonstrate that hydrogen bonding between HQPSf and CS can promote microphase separation in the resulting blend AEM, and an optimal amount of CS is important in balancing anion permeation and selectivity of the membrane. With a CS percentage of 3 % (by mass), the blend AEM yields the highest current efficiency (η) of 93.30 %, the lowest energy consumption (EC) of 4.23 kWh kg−1, and the highest selective permeability (Pm) of 96.86 % when used for electrodialysis (ED), which are far superior to the performance of unmodified HQPSf membrane (η = 86.79 %, EC = 4.57 kWh kg−1) and the commercial TWEDAI anion exchange membrane (η = 86.74 %, EC = 4.74 kWh kg−1). This work provides a facile, effective strategy to fabricate high performance AEMs for electrodialysis application.