# US 10,118,848 B2 · Inhibition of silica scale using amine-terminated polyoxyalkylene

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- Number: US 10,118,848 B2
- Document ID: US10118848B2
- Status: Granted
- Kind: B2
- Application number: 15/316,322
- Filed: 2015-06-02
- Published: 2017-07-13
- Granted: 2018-11-06
- Earliest claimed: 2014-06-19
- Assignees: Dow Global Technologies LLC; Rohm and Haas Company
- Applicants: Dow Global Technologies LLC; Rohm and Haas Company
- Inventors: Somil Chandrakant Mehta; Alain DuFour
- Web page: https://patentgrep.com/patent/US10118848B2

## CPC

- C02F 5/12: containing nitrogen (C02F5/14 takes precedence)
- C02F 1/441: {by reverse osmosis}
- C08G 65/08: Saturated oxiranes
- C02F 2101/10: Inorganic compounds
- C02F 2103/023: {Water in cooling circuits}
- C02F 2103/10: from quarries or from mining activities
- C02F 2103/28: from the paper or cellulose industry
- C02F 2303/22: Eliminating or preventing deposits, scale removal, scale prevention (C02F1/042, C02F1/4602, C02F5/00 take precedence)
- C02F 2305/04: Surfactants, used as part of a formulation or alone
- 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)
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS

## Abstract

A method for inhibiting silica scale formation in an aqueous system by adding an amine-terminated polyoxyalkylene anti-scalant to the water used in the aqueous system.

## Claims

### Claim 1

A method for inhibiting silica scale formation in an aqueous reverse osmosis system including a reverse osmosis membrane, wherein the method comprises the steps of:
adding an anti-scalant to a source of feed water having a pH of less than 9.5 and containing silica, and
passing the resulting feed water through the reverse osmosis system such that a portion passes through the reverse osmosis membrane to produce a permeate stream having a reduced concentration of silica with the remaining portion of feed water forming a reject stream having a higher concentration of silica;
wherein the anti-scalant comprises a non-ionic, tertiary amine-terminated polyoxyalkylene represented by:
wherein Y and Y′ are independently selected from hydrogen or alkyl; R1 is a C1 to C20 hydrocarbon moiety: R2 is a C10 to C14 hydrocarbon moiety; and E is a terminal end group selected from hydrogen, alkyl, NR1R2; L is a linking group selected from a direct bond between the oxyalkylene repeating unit —(CH2CH(Y)O)— and the nitrogen atom, or a C1 to C20 hydrocarbon moiety; n is an integer from 2 to 1000; and m is an integer from 0 to 1000.

### Claim 2 (depends on 1)

The method of claim 1 wherein the anti-scalant has a Mw of 100 to 100,000 Daltons.

### Claim 3 (depends on 1)

The method of claim 1 wherein the feed water has a pH less than 9 and a silica content of at least 30 ppm, and wherein the reject stream has a silica content of at least 100 ppm.

### Claim 4 (depends on 1)

The method of claim 1 wherein from 1 to 1000 ppm of the anti-scalant is added to the water of the aqueous system.