公开(公告)号：US20240025772A1

公开(公告)日：2024-01-25

申请号：US18266259

申请日：2021-12-24

Applicant: KURITA WATER INDUSTRIES LTD.

Inventor： Yuta OHTSUKA ,  Kunihiro HAYAKAWA ,  Gou NAKAGAWA

IPC: C02F1/44 ,  C02F1/76 ,  B01D65/08

CPC classification number: C02F1/441 ,  C02F1/76 ,  B01D65/08 ,  C02F2303/20 ,  B01D2321/168

Abstract: The purpose of the present invention is to provide a technique whereby it becomes possible to operate for a longer period of time in an aqueous system equipped with a membrane separation apparatus. The present invention can provide a membrane separation method, the method comprising containing a combined-chlorine-based oxidizing agent to water of interest, and allowing the water of interest which contains the combined-chlorine-based oxidizing agent to pass through a membrane separation apparatus, in which the water of interest which contains the combined-chlorine-based oxidizing agent has a Free 300-second value of 0.036 mg/L-Cl2 or more wherein the Free 300-second value is a result of the measurement of a chlorine concentration after 300 seconds using a free chlorine measurement reagent.

公开(公告)号：US20250051203A1

公开(公告)日：2025-02-13

申请号：US18721662

申请日：2022-12-15

Applicant: KURITA WATER INDUSTRIES LTD.

Inventor： Yuta OHTSUKA ,  Chikako SHIMPO ,  Gou NAKAGAWA ,  Junichi TAKAHASHI ,  Kunihiro HAYAKAWA

IPC: C02F1/76 ,  C02F1/44

Abstract: A method for preventing microorganism fouling in a water system containing a reducing agent, said microorganism fouling prevention method for a water system being characterized by adding a stabilized chlorine-based oxidizing agent composed of a chlorine-based oxidizing agent and a sulfamic acid compound, with the ratio of the sulfamic acid compound relative to 1 mol effective chlorine of the chlorine-based oxidizing agent being 1-1.5 mol, and/or a stabilized bromine-based oxidizing agent composed of a bromine-based oxidizing agent and a sulfamic acid compound, with the ratio of the sulfamic acid compound relative to 1 mol effective chlorine conversion amount of the bromine-based oxidizing agent being 1-1.5 mol, to the water system, such that the addition concentration of the stabilized chlorine-based oxidizing agent and/or the stabilized bromine-based oxidizing agent relative to the reducing agent concentration in the water system is 2.5 times or more by molar ratio.