Composite membranes for separation of gases
Membranes, methods of making the membranes, and methods of using the membranes are described herein. The membranes can comprise a gas permeable support layer, an inorganic layer disposed on the support, the inorganic layer comprising a plurality of discreet nanoparticles having an average particle size of less than 1 micron, and a selective polymer layer disposed on the inorganic layer, the selective polymer layer comprising a selective polymer having a CO 2 :N 2 selectivity of at least 10 at 57° C. In some embodiments, the membrane can be selectively permeable to an acidic gas. The membranes can be used, for example, to separate gaseous mixtures, such as flue gas.
1. A membrane comprising:
a gas permeable support layer,
an inorganic layer disposed on the gas permeable support layer, the inorganic layer comprising a plurality of discreet nanoparticles having an average particle size of less than 1 micron, and
a selective polymer layer disposed on the inorganic layer, the selective polymer layer comprising a selective polymer having a CO 2 :N 2 selectivity of at least 10 at 57° C.;
wherein the selective layer comprises a combination of amino compound and a hydrophilic polymer.
2. The membrane of claim 1 , wherein the gas permeable support layer comprises a gas permeable polymer.
3. The membrane of claim 2 , wherein the gas permeable polymer comprises a polymer selected from the group consisting of polyamides, polyimides, polypyrrolones, polyesters, sulfone-based polymers, polymeric organosilicones, fluorinated polymers, polyolefins, copolymers thereof, and blends thereof.
4. The membrane of claim 1 , wherein the gas permeable support layer comprises a gas permeable polymer disposed on a base.
5. The membrane of claim 4 , wherein the base comprises a non-woven fabric.
6. The membrane of claim 1 , wherein the nanoparticles are selected from the group consisting of alkaline earth metal oxide nanoparticles; lanthanide metal oxide nanoparticles; group IVA metal oxide nanoparticles; transition metal nanoparticles; metal alloy nanoparticles; silicate nanoparticles; clays; and combinations thereof.
7. The membrane of claim 1 , wherein the nanoparticles comprise silicate nanoparticles.
8. The membrane of claim 7 , wherein the nanoparticles comprise zeolite Y nanoparticles.
9. The membrane of claim 1 , wherein the average particle size of the nanoparticles is from 1 nm to 200 nm.
10. The membrane of claim 9 , wherein the average particle size of the nanoparticles is from 1 nm to 50 nm.
11. The membrane of claim 1 , wherein the selective polymer has a CO 2 :N 2 selectivity of from 10 to 500 at 57° C.
12. The membrane of claim 1 , wherein the amino compound comprises an amine-containing polymer.
13. The membrane of claim 1 , wherein the amino compound comprises a low molecular weight amino compound.
14. The membrane of claim 13 , wherein the low molecular weight amino compound comprises a salt of a primary amine or a salt of a secondary amine.
15. The membrane of claim 13 , wherein the low molecular weight amino compound comprises an aminoacid salt defined by a general formula below
wherein R 1 , R 2, 3 , and R 4 are hydrogen or hydrocarbon groups having from 1 to 4 carbon atoms, n is an integer ranging from 0 to 4, and A m+ is a cation having a valence of 1 to 3, and m is an integer equal to the valence of the cation.
16. The membrane of claim 1 , wherein the hydrophilic polymer comprises a polymer selected from the group consisting of polyvinylalcohol, polyvinylacetate, polyethylene oxide, polyvinylpyrrolidone, polyacrylamide, a polyamine copolymers thereof, and blends thereof.
17. The membrane of claim 1 , wherein the selective polymer further comprises a cross-linking agent.
18. A method of making a membrane comprising,
depositing a nanoparticle dispersion on a gas permeable support layer to form an inorganic layer disposed on the gas permeable support layer, wherein the nanoparticle dispersion comprises a plurality of discreet nanoparticles having an average particle size of less than 1 micron; and
coating the inorganic layer with a selective polymer,
wherein the selective layer comprises a combination of amino compound and a hydrophilic polymer,
wherein the selective polymer exhibits a CO 2 :N 2 selectivity of at least 10 at 57° C.
19. A method for separating a gaseous mixture comprising a first gas and a second gas, the method comprising contacting a membrane defined by claim 1 with the gaseous mixture under conditions effective to afford transmembrane permeation of the first gas.
20. The membrane of claim 1 , wherein the nanoparticles comprise an alumino-silicate nanoparticles.