| abstract |
An electrodeionization apparatus has a cathode and an anode, and has alternately formed therebetween concentrating chambers and desalination chambers by alternately arranging a plurality of anion exchange membranes and cation exchange membranes, each of the concentrating chambers being provided with a bipolar membrane to partition the interior of the concentrating chamber into a cathode side and an anode side, and each of the desalination chambers being divided into at least two layers including a first layer and a second layer, from an upstream side in a direction of flow of water to be treated, and being filled with an ion exchanger comprising an anion exchanger and a cation exchanger. The ion exchanger filling the first layer contains no less than 50 vol % of the cation exchanger, while the ion exchanger filling the second layer contains over 50 vol % to 80 vol % of the anion exchanger. As a result, the electrodeionization apparatus can be stably operated for a prolonged period of time while preventing formation of scale in the concentrating chambers and desalination chambers. |