The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Date of Patent:
Jun. 04, 2019

Filed:

Apr. 09, 2013
Applicant:

Kurita Water Industries Ltd., Nakano-ku, Tokyo, JP;

Inventors:

Tetsuya Aoki, Tokyo, JP;

Takahiro Kawakatsu, Tokyo, JP;

Kunihiro Hayakawa, Tokyo, JP;

Assignee:
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
B01D 65/02 (2006.01); C11D 7/04 (2006.01); C11D 7/08 (2006.01); C11D 7/10 (2006.01); C11D 11/00 (2006.01); B01D 65/10 (2006.01); C02F 1/44 (2006.01); C11D 7/06 (2006.01); C11D 7/34 (2006.01);
U.S. Cl.
CPC ...
B01D 65/02 (2013.01); B01D 65/10 (2013.01); C02F 1/441 (2013.01); C11D 7/04 (2013.01); C11D 7/06 (2013.01); C11D 7/08 (2013.01); C11D 7/10 (2013.01); C11D 7/34 (2013.01); C11D 11/0041 (2013.01); B01D 2321/164 (2013.01); B01D 2321/168 (2013.01); C02F 2303/16 (2013.01); C02F 2303/20 (2013.01);
Abstract

The invention provides cleaning agents, cleaning liquids and cleaning methods that effectively remove contaminants which are impossible to remove sufficiently with conventional cleaning liquids at the occurrence of a decrease in performances such as permeation flux and salt rejection rate due to contamination of permeable membranes, in particular aromatic polyamide RO membranes used in water treatment. Permeable membranes are cleaned with a cleaning liquid which is an aqueous solution including a chloramine compound and an alkali agent and having a pH of 10 or above. The chloramine compound is preferably one obtained by mixing a compound having a primary amino group with hypochlorous acid and/or a hypochlorite.


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