PURE WATER PRODUCTION METHOD, PURE WATER PRODUCTION DEVICE, AND ULTRA-PURE WATER PRODUCTION SYSTEM

WIPO Patent Application WO/2024/090356

A1

By reducing the processing load of three stages of reverse osmosis membrane devices on the preliminary stage side, the present invention makes it possible to reduce the chemical agent usage quantity and efficiently produces pure water having boron removed therefrom. Provided are a pure water production method and device. The pure water production method processes source water using at least three stages of ultra-low-pressure reverse osmosis membrane devices. Each reverse osmosis membrane is a negatively charged membrane that has a skin layer comprising a crosslinked aromatic polyamide, and the source water includes 1-100 mg/L of carbonic acid and 150 μg/L or less of boron. The pure water production method comprises a step in which the source water is processed using the reverse osmosis membrane device of the first stage, a step in which alkaline water subject to processing is obtained, a step in which the alkaline water subject to processing is processed using the reverse osmosis membrane device of the second stage, and a step in which the resulting permeate is processed using the reverse osmosis membrane device of the third stage to obtain pure water in which the boron concentration is 3-20 μg/L and the electrical conductivity is 0.3-40 μS/cm.

NOGUCHI YUKIO (JP)
YAMADA KENGO (JP)

PCT/JP2023/038072

May 02, 2024

October 20, 2023

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NOMURA MICRO SCIENCE KK (JP)

B01D19/00; B01D61/02; B01D61/14; B01D61/44; B01D61/58; B01D69/02; B01D71/56; C02F1/32; C02F1/42; C02F1/44; C02F1/469

WO2020003831A1

2020-01-02

JP2000061464A	2000-02-29
JP2018030065A	2018-03-01
JPH09234349A	1997-09-09
US5997745A	1999-12-07

KOBAYASHI TAKUMI (JP)

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