Performance evaluation of electrodeionization process based on ionic equilibrium with plate and frame modules

The paper describes results of experiments carried out in plate and frame electrodeionization (EDI) modules, aiming to elucidate ion mass transfer phenomena between ion-exchange resin and membrane for more effective desalination. The selective separation rate of different ions in process was investigated with conventional theories such as double electric layer and the Donnan theory to check its consistence. Further, as comparing with ordinary electrodialysis (ED) process, no obvious limiting current point was observed in EDI performance, which was usually used as a criterion for process optimization. Behavior of ion migration in the fluids with different configurations under different operating parameters was also examined and the ionic equilibrium analysis of EDI process was found to be beneficial to determine whether it was in the steady state or in the regeneration stage of operation.