| 摘要 |
PROBLEM TO BE SOLVED: To obtain a non-regeneration type ion exchange resin reduced in the leak of sodium by bringing an OH-type strong basic anion exchange resin into contact with an aq. soln. such as aq. ammonia in the absence of a cation exchange resin to reduce sodium remaining in the anion exchange resin. SOLUTION: In an ultrapure water making system, a terminal non- regeneration type ion exchange resin is supplied as an H-type strong acidic cation exchange resin and an OH-type strong basic anion exchange resin by purifying a strong acidic cation exchange resin and a strong basic anion exchange resin. In this case, in order to reduce the elution of sodium, the purified OH-type strong basic anion exchange resin is brought into contact with aq. ammonia or an aq. soln. of amine or amino-alcohol showing alkalinity, that is, ethanolamine or tetramethylammonium hydroxide in the absence of a cation exchange resin. By this method, sodium remaining in the anion exchange resin is reduced. |
