# US 12,179,142 B1 · Mixed matrix membrane with a covalent organic framework for selective CO2 separation

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- Number: US 12,179,142 B1
- Document ID: US12179142B1
- Status: Granted
- Kind: B1
- Application number: 18/765,778
- Filed: 2024-07-08
- Granted: 2024-12-31
- Earliest claimed: 2024-07-08
- Assignees: King Fahd University of Petroleum and Minerals
- Applicants: King Fahd University of Petroleum and Minerals
- Inventors: Mohd Yusuf Khan; Bosirul Hoque
- Web page: https://patentgrep.com/patent/US12179142B1

## CPC

- B01D 53/0454: {Controlling adsorption (controlling temperature swing adsorption B01D53/0462, controlling pressure swing adsorption B01D53/047)}
- B01D 53/22: by diffusion (manufacturing semi-permeable membranes B01D67/00; form, structure or properties of semi-permeable membranes B01D69/00; material for semi-permeable membranes B01D71/00)
- B01D 53/228: {characterised by specific membranes}
- B01J 20/226: {Coordination polymers, e.g. metal-organic frameworks [MOF], zeolitic imidazolate frameworks [ZIF] (preparation of metal complexes containing carboxylic acid moieties C07C51/418; MOF's per se C07F)}
- B01J 20/28033: {Membrane, sheet, cloth, pad, lamellar or mat}
- B01J 20/28061: {being in the range 100-500 m2/g}
- B01D 2253/202: Polymeric adsorbents
- B01D 2253/304: Linear dimensions, e.g. particle shape, diameter
- B01D 2253/306: Surface area, e.g. BET-specific surface
- B01D 2253/308: Pore size
- B01D 2257/504: Carbon dioxide
- B01J 20/28007: {with size in the range 1-100 nanometers, e.g. nanosized particles, nanofibers, nanotubes, nanowires or the like (carbon nanostructures B01J20/205)}
- B01J 20/2808: {being less than 2 nm, i.e. micropores or nanopores}
- Y02C 20/40: of CO2
- 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)
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- Y02C: CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG]

## Abstract

A method of separating a gas mixture, including contacting the gas mixture with a membrane and passing a portion of the gas mixture through the membrane. The portion of the gas mixture that passes through the membrane includes carbon dioxide. The membrane includes a poly(ether-block-amide) (PEBAX) and a covalent organic framework (COF). The COF is an optionally substituted COF-316 and the COF is dispersed in a matrix of the PEBAX to form the membrane. The membrane includes 0.1-5 wt. % of the COF relative to a total weight of the membrane.

## Claims

### Claim 1

A method of separating a gas mixture, including:
contacting the gas mixture with a membrane and passing a portion of the gas mixture through the membrane,
wherein the portion of the gas mixture that passes through the membrane includes carbon dioxide,
wherein the membrane includes:
a poly(ether-block-amide) (PEBAX); and
a covalent organic framework (COF),
wherein the COF is an optionally substituted COF-316,
wherein the COF is dispersed in a matrix of the PEBAX to form the membrane, and
wherein the membrane includes 0.1-5 wt. % of the COF relative to a total weight of the membrane.

### Claim 2 (depends on 1)

The method of claim 1, wherein particles of the COF are in a form of nanosheets having a length of 1-5 μm, a width of 1-5 μm, and a thickness of 10-50 nm.

### Claim 3 (depends on 2)

The method of claim 2, wherein the nanosheets align parallel to a surface of the membrane in the matrix of the PEBAX.

### Claim 4 (depends on 1)

The method of claim 1, wherein the COF has a BET surface area of 250-350 m2g−1.

### Claim 5 (depends on 1)

The method of claim 1, wherein the COF is crystalline.

### Claim 6 (depends on 1)

The method of claim 1, wherein the COF has a pore width of 12-15 Å.

### Claim 7 (depends on 1)

The method of claim 1, wherein the COF is stable up to 400° C.

### Claim 8 (depends on 1)

The method of claim 1, wherein the COF has the following structure:
wherein R1 is selected from the group consisting of a hydrogen, a hydroxyl, a carboxyl, an amine, a thiol, a nitrile, a cyanate, an isocyanate, and an amide, and
wherein the squiggly lines represent bonding to additional units of the COF.

### Claim 9 (depends on 1)

The method of claim 1, wherein the COF does not form aggregates in the membrane and is homogeneously dispersed.

### Claim 10 (depends on 1)

The method of claim 1, wherein the PEBAX is PEBAX-1657.

### Claim 11 (depends on 1)

The method of claim 1, wherein the passing the gas mixture is at a pressure of 1-5 bar.

### Claim 12 (depends on 1)

The method of claim 1, wherein the PEBAX and the COF do not interact through covalent bonds.

### Claim 13 (depends on 1)

The method of claim 1, wherein the membrane has a thickness of 20-200 μm.

### Claim 14 (depends on 1)

The method of claim 1, wherein the membrane has a density of 1.00 to 1.15 g/cm3.

### Claim 15 (depends on 1)

The method of claim 1, wherein the membrane has a free fractional volume of 14-22%.

### Claim 16 (depends on 1)

The method of claim 1, wherein the gas mixture further includes at least one selected from the group consisting of nitrogen, oxygen, and argon.

### Claim 17 (depends on 1)

The method of claim 1, wherein the membrane has a higher permeability for carbon dioxide than for other gases.

### Claim 18 (depends on 1)

The method of claim 1, wherein the membrane has a CO2 permeability 2-5 times larger than a membrane under the same conditions but without the COF.

### Claim 19 (depends on 1)

The method of claim 1, wherein the membrane includes 0.5 wt. % of the COF relative to a total weight of the membrane, and
wherein the membrane has a CO2/N2 selectivity 2-5 times larger than a membrane under the same conditions but without the COF.