Abstract
In order to study water ionization in the electrodeionization process, the transport of ions through the ion-exchange resin layer was examined. Ion-exchange resins were introduced between two platinum electrodes and impedance was measured under a flow of ultrapure water, suggesting that the transport of ions associated with the charge-discharge process of the electric double layer on the platinum electrodes is a diffusion-controlled process and that water ionization may proceed autocatalytically. From these results, water ionization in the electrodeionization process is discussed.