Zeolite membranes, molecular separation methods, and manufacturing processes for zeolite membranes
Disclosed are methods of manufacturing a zeolite membrane, comprising: providing at least one porous substrate; and coating the at least one porous substrate with a membrane. In some embodiments, the method further comprises hydrothermally treating the membrane with a first hydrothermal treatment step with tetrapropylammonium fluoride (TPAF) and a second hydrothermal treatment step with tetraethylammonium hydroxide (TEAOH). In some embodiments, coating the substrate with a membrane comprises surrounding at least a portion of the at least one porous substrate with a precursor gel, the gel comprising a gel phase and a plurality of CHA or MFI crystals; heating the at least one porous substrate and the precursor gel; washing the at least one porous substrate; drying the at least one porous substrate; and calcining the at least one porous substrate.
1. A method of manufacturing a zeolite membrane comprising:
coating at least a portion of a porous substrate with a membrane comprising nanomaterials; and
hydrothermally treating the membrane comprising:
a first hydrothermal treatment with a first substance; and
a second hydrothermal treatment with a second substance;
wherein the second hydrothermal treatment occurs after the first hydrothermal treatment.
2. The method of claim 1 , wherein the first substance comprises tetrapropylammonium fluoride (TPAF).
3. The method of claim 2 , wherein the second substance comprises tetraethylammonium hydroxide (TEAOH).
4. The method of claim 1 , wherein the second substance comprises tetraethylammonium hydroxide (TEAOH).
5. The method of claim 1 , wherein the first hydrothermal treatment occurs over a period of between 6 hours and 12 hours.
6. The method of claim 1 , wherein the second hydrothermal treatment occurs over a period of between 40 hours and 56 hours.
7. The method of claim 1 , wherein the porous substrate comprises an α-alumina porous hollow fiber.
8. The method of claim 1 , wherein hydrothermally treating the membrane increases adhesion of the membrane to the porous substrate.
9. The method of claim 1 , wherein the nanomaterials comprise nanosheets; and
wherein hydrothermally treating the membrane fills in at least a portion of voids located between the nanosheets.
10. The method of claim 1 , wherein the membrane has a thickness of less than 800 nm after the hydrothermal treatment.
11. The method of claim 1 , wherein out-of-plane orientation of the membrane is preserved after the hydrothermal treatment.
12. The method of claim 1 , wherein the coating occurs via a vacuum filtration process.
13. The method of claim 1 , wherein after the hydrothermal treatment, the membrane has:
an n-butane permeance in a range of 100-10,000 gas permeation units; and
a separation factor for n-butane/i-butane in a range of 10-100 at room temperature with a pressure difference in a range of 1-20 bar across the membrane.
14. The method of claim 1 , wherein after the hydrothermal treatment, the membrane has a separation factor for n-butane/methane in a range of 50-500 at room temperature with a pressure difference in a range of 1-20 bar across the membrane.
15. The method of claim 1 , wherein after the hydrothermal treatment, the membrane has a separation factor for propane/methane in a range of 10-100 at room temperature with a pressure difference in a range of 1-20 bar across the membrane.
16. The method of claim 1 , wherein the membrane is selected from the group consisting of a chabazite (CHA)-type zeolite membrane and a (MFI)-type zeolite membrane.
17. The method of claim 1 , wherein the coating comprises coating with a precursor gel.
18. A method of manufacturing a zeolite membrane comprising:
coating at least a portion of a porous substrate with a precursor gel; and
heating the porous substrate and the precursor gel comprising:
a first hydrothermal treatment with a first substance; and
a second hydrothermal treatment with a second substance;
wherein the second hydrothermal treatment occurs after the first hydrothermal treatment.
19. The method of claim 18 , wherein the precursor gel comprises silicon dioxide (SiO 2 ) and water (H 2 O) in a SiO 2 /H 2 O ratio of 5:1 to 10:1.
20. The method of claim 18 , wherein the precursor gel comprises silicon dioxide (SiO 2 ) and water (H 2 O) in a SiO 2 /H 2 O ratio of 5:1.
21. The method of claim 18 , wherein the precursor gel is manufactured by a process comprising:
combining sodium hydroxide, a trimethyladamantylammonium hydroxide (TMAdaOH) solution in water, and aluminum hydroxide while stirring to form a first mixture;
adding CHA crystals to the first mixture; and
evaporating at least a portion of the water in the first mixture in a silicone oil bath.
22. The method of claim 18 , wherein the precursor gel comprises
silicon dioxide (SiO 2 );
sodium oxide (Na 2 O);
aluminum oxide (Al 2 O 3 ); and
trimethyladamantylammonium hydroxide (TMAdaOH);
present in a molar composition of 1.0 SiO 2 : 0.1 Na 2 O: 0.005 Al 2 O 3 : 0.4 TMAdaOH.
23. The method of claim 1 , wherein membrane has carbon dioxide (CO2) permeance in a range of 1,000-20,000 gas permeation units under feed conditions at 0-100% humidity.
24. The method of claim 1 , wherein the membrane has a separation factor for carbon dioxide/methane in a range of 50-500 in a 1-7 bar feed pressure range.
25. The method of claim 1 , wherein the membrane has a separation factor for carbon dioxide/propane in a range of 100-2,000 in a 1-7 bar feed pressure range.
26. A zeolite membrane manufactured by the method of claim 1 .
27. The method of claim 1 , wherein the membrane is selected from the group consisting of a chabazite (CHA)-type zeolite membrane and a (MFI)-type zeolite membrane; and
wherein at least one of:
the membrane has carbon dioxide (CO2) permeance in a range of 1,000-20,000 gas permeation units under feed conditions at 0-100% humidity;
the membrane has a separation factor for carbon dioxide/methane in a range of 50-500 in a 1-7 bar feed pressure range; or
the membrane has a separation factor for carbon dioxide/propane in a range of 100-2,000 in a 1-7 bar feed pressure range.
28. The method of claim 19 further comprising:
washing the heat treated porous substrate;
drying the washed porous substrate; and
calcining the dried porous substrate.
29. The method of claim 18 , wherein the first hydrothermal treatment occurs at a temperature of between 273 K and 473 K; and
wherein the second hydrothermal treatment occurs at a temperature of between 273 K and 493 K.
30. The method of claim 18 , wherein the first hydrothermal treatment occurs for a time period of between 1 hour and 72 hours; and
wherein the second hydrothermal treatment occurs for a time period of between 12 hours and 82 hours.
31. The method of claim 19 , wherein membrane has carbon dioxide (CO 2 ) permeance in a range of 1,000-20,000 gas permeation units under feed conditions at 0-100% humidity.
32. The method of claim 19 , wherein the membrane has a separation factor for carbon dioxide/methane in a range of 50-500 in a 1-7 bar feed pressure range.
33. The method of claim 19 , wherein the membrane has a separation factor for carbon dioxide/propane in a range of 100-2,000 in a 1-7 bar feed pressure range.
34. A zeolite membrane manufactured by the method of claim 19 .