Electric Field Distribution and Its Influence on Electrodialysis Efficiency: Mitigation Strategies

This study investigates the impact of secondary electric fields on electrodialysis efficiency caused by the permeability of ion exchange membranes leading to local differences in ion concentration. The study traces the mechanism that creates non-uniformity in electrodialysis and derives an equation for the distribution properties governing the secondary electric field. A finite element simulation model was established to investigate the secondary electric field derivation phenomenon in the electrodialysis system. This model includes the electric field and concentration distribution in the chamber, ion exchange membrane (IEM), and its interface area in the flat electrode electrodialysis system, and an optimized electrode shape was designed to reduce the electric field’s non-uniformity and improve electrodialysis efficiency. An analysis of the results showed that the optimized electrode improves electrodialysis efficiency by weakening the secondary electric field and reducing the non-uniformity in the electric field distribution. Field experiments were conducted to quantitatively analyze an electrodialysis system’s uneven electric field distribution and its impact on electrodialysis efficiency. These experiments confirmed that the non-uniformity induced by the secondary electric field in the electrodialysis system indeed influences electrodialysis efficiency, and the optimized electrode reduces the secondary electric field and improves efficiency.