# US 2025/0368554 A1 · Treatment method for fluorine- and aluminum-containing water

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- Number: US 2025/0368554 A1
- Document ID: US20250368554A1
- Status: Published application
- Kind: A1
- Application number: 18/867,442
- Filed: 2023-05-18
- Published: 2025-12-04
- Earliest claimed: 2022-06-02
- Assignees: Kurita Water Industries Ltd.
- Applicants: Kurita Water Industries Ltd.
- Inventors: Hidekuni KAMEDA
- Web page: https://patentgrep.com/patent/US20250368554A1

## CPC

- C02F 1/683: {by addition of complex-forming compounds}
- B01D 61/02: Reverse osmosis; Hyperfiltration {; Nanofiltration}
- C02F 1/44: by dialysis, osmosis or reverse osmosis {(general membrane separation processes B01D61/00, membrane modules B01D63/00, electrodialysis C02F1/4693, combination of membrane modules and bioreactors C02F3/1268)}
- C02F 1/441: {by reverse osmosis}
- C02F 1/444: {by ultrafiltration or microfiltration}
- C02F 1/5245: {using basic salts, e.g. of aluminium and iron}
- C02F 1/66: by neutralisation; pH adjustment (for degassing C02F1/20; using ion-exchange C02F1/42; for flocculation or precipitation of suspended impurities C02F1/52; for removing dissolved compounds C02F1/58)
- C02F 2101/14: Fluorine or fluorine-containing compounds
- C02F 2101/20: Heavy metals or heavy metal compounds
- C02F 2103/346: {from semiconductor processing, e.g. waste water from polishing of wafers}
- C02F 2209/06: pH
- C02F 2209/20: Total organic carbon [TOC]
- C02F 2305/00: Use of specific compounds during water treatment
- C02F: TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE (separation in general B01D; special arrangements on waterborne vessels of installations for treating water, waste water or sewage, e.g. for producing fresh water, B63J; adding materials to water to prevent corrosion C23F; treating radioactively-contaminated liquids G21F9/04; regeneration of reactants for recirculation into processes, see the relevant places for the processes)
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)

## Abstract

The present invention provides a treatment method for fluorine- and aluminum-containing water, in which a chelating agent is added to fluorine- and aluminum-containing water in an amount of 100 times or more by weight of the aluminum concentration in the fluorine- and aluminum-containing water, and then water is passed through a reverse osmosis membrane device. The pH of the fluorine- and aluminum-containing water is preferably 4 to 6. The chelating agent is preferably EDTA. The F ion concentration in the water to be treated is preferably 50 to 700 mg/L, and the Al ion concentration therein is preferably 0.01 to 1 mg/L.

## Claims

### Claim 1

A treatment method for fluorine- and aluminum-containing water, comprising:
adding a chelating agent to fluorine- and aluminum-containing water in an amount of 100 times or more by weight of an aluminum concentration in the fluorine- and aluminum-containing water; and
passing water through a reverse osmosis membrane device.

### Claim 2 (depends on 1)

The treatment method for fluorine- and aluminum-containing water according to claim 1, wherein a pH of the fluorine- and aluminum-containing water is 4 to 6.

### Claim 3 (depends on 1)

The treatment method for fluorine- and aluminum-containing water according to claim 1, wherein the chelating agent is EDTA.

### Claim 4 (depends on 1)

The treatment method for fluorine- and aluminum-containing water according to claim 1, wherein the chelating agent is added to the fluorine- and aluminum-containing water in an amount of 100 to 1500 times by weight of the aluminum concentration in the fluorine- and aluminum-containing water.

### Claim 5 (depends on 1)

The treatment method for fluorine- and aluminum-containing water according to claim 1, wherein the chelating agent is added to the fluorine- and aluminum-containing water in an amount of 800 to 1500 times by weight of the aluminum concentration in the fluorine- and aluminum-containing water.

### Claim 6 (depends on 1)

The treatment method for fluorine- and aluminum-containing water according to claim 1, wherein an F ion concentration in the fluorine- and aluminum-containing water is 50 to 700 mg/L, and an Al ion concentration is 0.01 to 1 mg/L.

### Claim 7 (depends on 1)

The treatment method for fluorine- and aluminum-containing water according to claim 1, wherein a TOC concentration in the fluorine- and aluminum-containing water is 10 mg/L, or less.