REGENERATED ULTRAFILTRATION ELEMENT

Japanese Patent JP3637751

B2

PROBLEM TO BE SOLVED: To reuse a reverse osmosis membrane element as an ultrafiltration membrane by treating a membrane surface of a composite reverse osmosis membrane element that has undergone membrane deterioration with at least one solution selected from the group of an aqueous solution of oxidizing agent, an aqueous solution of a reducing agent, and aqueous solution of an acid or alkali so as to remove an active layer on the membrane surface.
SOLUTION: When a composite reverse osmosis membrane element having a deteriorated performance due to membrane deterioration is treated, first the element is treated with an aqueous treatment solution so as to remove an active layer that has undergone performance deterioration. Treatment solutions are suitably, not limited, an aqueous solution of an oxidizing agent such as sodium hypochlorite, hydrogen peroxide, nitric acid, ozone or the like, and an aqueous solution of a reducing agent such as hydrazine, formic acid or the like, an aqueous solution of an acid such as hydrochloric acid, sulfuric acid or the like and an aqueous solution of an alkali such as sodium hydroxide, potassium hydroxide or the like. Next, the remaining solution on the element is removed and washed with water and drained off. The element thus obtained by these treatment is reused as a regenerated ultrafiltration membrane element.

Hisao Hachisuka
Kenichi Ikeda

JP33795197A

April 13, 2005

November 21, 1997

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NITTO DENKO CORPORATION

B01D61/10; B01D61/18; B01D67/00; B01D69/12; (IPC1-7): B01D67/00; B01D61/18; B01D69/12

JP51119685A
JP63166404A

Hiroshi Morioka

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