# US 11,439,957 B2 · Desalination membranes

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- Number: US 11,439,957 B2
- Document ID: US11439957B2
- Status: Granted
- Kind: B2
- Application number: 17/097,744
- Filed: 2020-11-13
- Published: 2022-05-19
- Granted: 2022-09-13
- Earliest claimed: 2020-11-13
- Assignees: Saudi Arabian Oil Company; King Fahd University of Petroleum and Minerals
- Applicants: Saudi Arabian Oil Company; King Fahd University of Petroleum & Minerals
- Inventors: Umair Baig; Turki Nabieh Baroud; Hasan Al Abdulgader
- Web page: https://patentgrep.com/patent/US11439957B2

## CPC

- B01D 67/0093: {Chemical modification}
- B01D 67/0011: {Casting solutions therefor}
- B01D 67/0013: {Casting processes}
- B01D 67/00165: {Composition of the coagulation baths}
- B01D 67/00793: {Dispersing a component, e.g. as particles or powder, in another component}
- B01D 67/0088: {Physical treatment with compounds, e.g. swelling, coating or impregnation}
- B01D 67/009: {with wave-energy, particle-radiation or plasma}
- B01D 69/02: characterised by their properties
- B01D 69/148: {Organic/inorganic mixed matrix membranes}
- B01D 71/024: {Oxides}
- B01D 71/34: Polyvinylidene fluoride
- B01D 71/441: {Polyvinylpyrrolidone}
- B01D 71/78: Graft polymers
- B01D 71/82: characterised by the presence of specified groups, e.g. introduced by chemical after-treatment
- B01D 2323/04: Hydrophobization
- B01D 2323/21: Fillers
- B01D 2323/36: Introduction of specific chemical groups
- B01D 2325/38: Hydrophobic membranes
- Y02A 20/131: Reverse-osmosis
- 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)
- Y02A: TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE

## Abstract

Polymer-based membranes and methods for fabricating membranes are described. The methods include forming a casting solution featuring a plurality of titanium dioxide (TiO2) nanoparticles, a polyvinylidene fluoride (PVDF)-based solvent, and a polyvinylpyrrolidone (PVP)-based modifying agent, dispersing the casting solution to form a first element, generating a plurality of active sites on a surface of the first element, and forming a polymer-based membrane by exposing the surface of the first element to a fluorosilane composition to form a fluorosilane layer on the surface, where the fluorosilane composition includes a silane compound having at least one alkyl substituent that includes between 9 and 21 fluorine atoms.

## Claims

### Claim 1

A method for fabricating a polymer-based membrane, the method comprising:
forming a casting solution comprising a plurality of titanium dioxide (TiO2) nanoparticles, a polyvinylidene fluoride (PVDF)-based solvent, and a polyvinylpyrrolidone (PVP)-based modifying agent;
dispersing the casting solution to form a first element;
generating a plurality of active sites on a surface of the first element; and
forming a polymer-based membrane by exposing the surface of the first element to a fluorosilane composition to form a fluorosilane layer on the surface, wherein the fluorosilane composition comprises a silane compound comprising at least one alkyl substituent comprising between 9 and 21 fluorine atoms.

### Claim 2 (depends on 1)

The method of claim 1, wherein exposing the surface of the first element to the fluorosilane composition comprises dip-coating the surface in the fluorosilane composition to form the fluorosilane layer.

### Claim 3 (depends on 1)

The method of claim 1, wherein generating the plurality of active sites comprises plasma etching the surface of the first element.

### Claim 4 (depends on 1)

The method of claim 1, wherein forming the casting solution comprises dissolving a polyvinylidene fluoride-based agent in a solvent.

### Claim 5 (depends on 4)

The method of claim 4, wherein the polyvinylidene fluoride-based agent comprises unsubstituted polyvinylidene fluoride.

### Claim 6 (depends on 4)

The method of claim 4, wherein the polyvinylidene fluoride-based agent comprises at least one substituted polyvinylidene fluoride compound.

### Claim 7 (depends on 6)

The method of claim 6, wherein the polyvinylidene fluoride-based agent comprises unsubstituted polyvinylidene fluoride and at least one substituted polyvinylidene fluoride compound.

### Claim 8 (depends on 4)

The method of claim 4, wherein a molar percentage concentration of the polyvinylidene fluoride-based agent in the casting solution is between 5% and 20%.

### Claim 9 (depends on 1)

The method of claim 1, further comprising forming the first element by coagulating the dispersed casting solution in a coagulation bath.

### Claim 10 (depends on 1)

The method of claim 1, wherein dispersing the casting solution comprises dispersing the casting solution on a surface using a casting knife.

### Claim 11 (depends on 1)

The method of claim 1, wherein the fluorosilane composition comprises at least one fluorinated chlorosilane compound.

### Claim 12 (depends on 11)

The method of claim 11, wherein the at least one fluorinated chlorosilane compound comprises at least one alkyl substituent covalently bonded to a silicon atom of the at least one chlorosilane compound, and wherein the at least one alkyl substituent comprises at least 9 fluorine atoms.

### Claim 13 (depends on 11)

The method of claim 11, wherein the fluorinated chlorosilane compound comprises 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,12-heneicosafluorododecyltrichlorosilane (CF3(CF2)9CH2CH2SiCl3).

### Claim 14 (depends on 11)

The method of claim 11, wherein a weight percentage of the at least one fluorinated chlorosilane compound in the membrane is between 5 weight % and 50 weight %.

### Claim 15

A polymer-based membrane comprising:
a first element comprising a plurality of titanium dioxide (TiO2) nanoparticles, a polyvinylpyrrolidone (PVP) modifying agent and a polyvinylidene fluoride (PVDF)-based compound; and
a fluorosilane layer disposed on the first element and comprising at least one fluorinated chlorosilane compound,
wherein a water contact angle for the membrane is greater than 150°; and
wherein an oil contact angle for the membrane is greater than 100°.

### Claim 16 (depends on 15)

The membrane of claim 15, wherein the at least one fluorinated chlorosilane compound comprises a chlorosilane compound comprising at least one alkyl substituent covalently bonded to a silicon atom of the chlorosilane compound, and wherein the at least one alkyl substituent comprises at least 9 fluorine atoms.

### Claim 17 (depends on 16)

The membrane of claim 16, wherein the at least one alkyl substituent is a primary alkyl substituent that comprises 9, 17, or 21 fluorine atoms.

### Claim 18 (depends on 16)

The membrane of claim 16, wherein the at least one fluorinated chlorosilane compound comprises 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,12-heneicosafluorododecyltrichlorosilane (CF3(CF2)9CH2CH2SiCl3).

### Claim 19 (depends on 15)

The membrane of claim 15, wherein the at least one fluorinated chlorosilane compound comprises a chlorosilane compound comprising at least two hydrocarbon substituents covalently bonded to a silicon atom of the chlorosilane compound, and wherein at least one of the at least two hydrocarbon substituents comprises fluorine atoms.

### Claim 20 (depends on 15)

The membrane of claim 15, wherein a weight percentage of the at least one fluorinated chlorosilane compound in the membrane is between 5 weight % and 50 weight %.