| 摘要 |
PURPOSE:To further improve the quality of ultrapure water as compared with the present quality and to miniaturize the apparatus by treating raw water with a hollow yarn membrane having a specified ultrafiltration velocity before the water is treated with an ion exchanger. CONSTITUTION:An ion exchanger at least a part of which is composed of an ion-exchange fiber is used for producing ultrapure water. In this method, raw water is treated with a hollow yarn membrane having 5-2,000ml/hr.m<2>.mmHg ultrafiltration velocity and whose inner diameter is regulated to 150-350mu (10-100mu film thickness) before the water is treated with an ion exchanger. Consequently, the quality of ultrapure water is further improved as compared with the present quality and the apparatus can be miniaturized. |
