| 摘要 |
PROBLEM TO BE SOLVED: To provide a deionized water production method which enables the electrical resistance of an electrical water deionizer to be reduced by a radical improvement in structure of the deionizer without adding any chemical agent to concentrated water, to inhibit scale from being formed in concentration chambers and to perform stable production of deionized water having high grade water quality over a long period by improving the capability of removing ions from water to be treated, of the deionizer. SOLUTION: This electrical water deionizer 10 is provided with a deionization chamber D1 that is formed by packing two small deionization chambers d1 and d2, which are divided by a cation exchange membrane 3 on one side, an anion exchange membrane 4 on the other side and a central intermediate ion exchange membrane 5, with an ion exchanger 8; two concentration chambers 1 which are placed on the both sides of the deionization chamber D1 through the cation exchange membrane 3 and anion exchange membrane 4 respectively; and the chamber D1 and the cambers 1 are placed between an anode 7 and cathode 6. This production method using the deionizer 10 comprises allowing water to be treated to flow into one small deionization chamber d2 while applying a voltage to between the anode 7 and cathode 6 so that the current density is >=20 mA/dm2, then allowing outflow water from the chamber d2 to flow into the other small deionization chamber d1, and concurrently, allowing concentrated water into the concentration chambers 1, to remove impurity ions in the water to be treated and to produce the objective deionized water.
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