Abstract
Effective design and operation of electrodeionization process (EDI) require an appropriate simulation model. However, such a model has not been established because of the complexity of the reaction and transport phenomena in the EDI processes. This paper discusses various problems in constructing a simulation model for the EDI processes through an introduction of the researches of the authors and Neumeister et al. The authors' works on the regeneration of ion-exchange resins gave a clue to understand the EDI processes, where regeneration and sorption were simultaneously done. In these works, which were carried out in a relatively large electrodialyzer, some models were first proposed to provide fundamental information for the design of regeneration system of ion exchange resins. The Neumeister et al.'s works were on the development of EDI process for the production of ultrapure water. They proposed a 2D-model to simulate their experimental results. The model, which was based on the rate-determining step of film diffusion, succeeded in explaining the behavior of ions in the EDI process. Their model successfully simplified the complicated phenomena in the process, which suggested a direction for the model construction for the EDI processes. On the basis of the information from the authors' and Neumeister et al.'s works, discussion was done to establishan appropriate model of the EDI processes.
