Method for preparing a porous inorganic coating on a porous support using certain pore fillers

• US 20080299349A1
• Filed: 07/19/2007
• Published: 12/04/2008
• Est. Priority Date: 05/31/2007
• Status: Active Grant

• Current Assignee: Corning Incorporated
• Original Assignee: Corning Incorporated
• Inventors: Wang, Jianguo, Liu, Wei, Gu, Yunfeng
• Granted Patent: US 7,767,256 B2
• Time in Patent Office: Days
• US Class Current: 428/137
• CPC Class Codes: B01D 2323/42 Details of membrane preparation apparatus
• CPC Class Codes: B01D 63/066 with a porous block having membrane coated passages
• CPC Class Codes: B01D 67/0046 by slurry techniques, e.g. die or slip-casting
• CPC Class Codes: C04B 2111/00801 Membranes; Diaphragms
• CPC Class Codes: C04B 35/10 based on aluminium oxide
• CPC Class Codes: C04B 35/185 Mullite 3Al2O3-2SiO2
• CPC Class Codes: C04B 35/195 Alkaline earth aluminosilicates, e.g. cordierite or anorthite
• CPC Class Codes: C04B 35/46 based on titanium oxides or titanates containing also zirconium or hafnium oxides, zirconates or hafnates C04B35/49
• CPC Class Codes: C04B 35/478 based on aluminium titanates
• CPC Class Codes: C04B 35/48 based on zirconium or hafnium oxides, zirconates, zircon or hafnates
• CPC Class Codes: C04B 35/50 based on rare-earth compounds non-oxide rare earth compounds C04B35/5156
• CPC Class Codes: C04B 41/009 characterised by the material treated
• CPC Class Codes: C04B 41/4535 applied as a solution, emulsion, dispersion or suspension
• CPC Class Codes: C04B 41/455 the coating or impregnating process including a chemical conversion or reaction
• CPC Class Codes: C04B 41/457 Non-superficial impregnation or infiltration of the substrate
• CPC Class Codes: C04B 41/4582 Porous coatings, e.g. coating containing porous fillers
• CPC Class Codes: C04B 41/459 Temporary coatings or impregnations C04B40/04 takes precedence
• CPC Class Codes: C04B 41/4803 Polysaccharides, e.g. cellulose, or derivatives thereof
• CPC Class Codes: C04B 41/4807 Proteins or derivatives thereof
• CPC Class Codes: C04B 41/483 Polyacrylates
• CPC Class Codes: C04B 41/4876 : Polystyrene
• CPC Class Codes: C04B 41/5027 : Oxide ceramics in general; Specific oxide ceramics not covered by C04B41/5029 - C04B41/5051
• CPC Class Codes: C04B 41/5031 : Alumina
• CPC Class Codes: C04B 41/52 : Multiple coating or impregnating multiple coating or impregnating with the same composition or with compositions only differing in the concentration of the constituents, is classified as single coating or impregnation
• CPC Class Codes: C04B 41/522 : Multiple coatings, for one of the coatings of which at least one alternative is described
• CPC Class Codes: C04B 41/87 : Ceramics
• CPC Class Codes: C04B 41/89 : for obtaining at least two superposed coatings having different compositions
• CPC Class Codes: F01N 3/0222 : the structure being monolithic, e.g. honeycombs
• CPC Class Codes: Y10T 428/24149 : Honeycomb-like
• CPC Class Codes: Y10T 428/24322 : Composite web or sheet
• CPC Class Codes: Y10T 428/249981 : Plural void-containing components
• CPC Class Codes: Y10T 428/2935 : Discontinuous or tubular or cellular core

Abstract

Methods for preparing porous inorganic coatings on porous supports using certain pore fillers, and porous supports coated with porous inorganic coatings. The porous inorganic coatings may serve as membranes useful in, for example, liquid-liquid, liquid-particulate, gas-gas, or gas-particulate separation applications.

Claims

1. A method for preparing a porous inorganic coating on a porous support, which comprises:

providing a porous support comprising a first end, a second end, and a plurality of inner channels having surfaces defined by porous walls and extending through the support from the first end to the second end;

modifying the inner channel surfaces of the support by applying to the inner channel surfaces a composition comprising an organic pore-filling material selected from protein particles, starch particles, synthetic polymer particles, and combinations thereof;

applying to the modified inner channel surfaces a coating comprising inorganic particles; and

heating the coated support to remove the organic pore-filling material, leaving a porous inorganic coating on the porous support.

2. The method of claim 1, wherein the provided porous support is in the form of a honeycomb monolith.

3. The method of claim 1, wherein the provided porous support is inorganic.

4. The method of claim 3, wherein the porous inorganic support is ceramic.

5. The method of claim 4, wherein the porous ceramic support comprises cordierite, alpha-alumina, mullite, aluminum titinate, titania, zirconia, ceria or combinations thereof.

6. The method of claim 1, wherein the inner channels of the provided support are circular and have an average diameter of from 0.5 to 2 mm.

7. The method of claim 1, wherein the pores of the porous walls of the provided support have a median pore size of 5 μ

m or greater.

8. The method of claim 1, wherein the organic pore-filling material comprises protein particles.

9. The method of claim 8, wherein the composition comprising the protein particles comprises an aqueous suspension of the protein particles.

10. The method of claim 9, wherein the composition comprising the protein particles is skim milk.

11. The method of claim 1, wherein the organic pore-filling material comprises starch particles.

12. The method of claim 11, wherein the starch particles comprise amaranth starch, quinoa starch, taro starch, or combinations thereof.

13. The method of claim 1, wherein the organic pore-filling material comprises synthetic polymer particles.

14. The method of claim 13, wherein the synthetic polymer particles comprise polystyrene, polyacrylate, an oligomer, or combinations thereof.

15. The method of claim 1, wherein the organic pore-filling material comprises particles having a median particle size of from 0.1 to 3 μ

m.

16. The method of claim 1, which comprises applying the composition comprising the organic pore-filling material to the inner channel surfaces of the support by dip coating, flow coating, slip casting, immersion, or combinations thereof.

17. The method of claim 1, wherein the coating comprising inorganic particles comprises cordierite, alumina, mullite, aluminum titinate, titania, zirconia, or ceria particles or combinations thereof.

18. The method of claim 1, wherein the coating comprising inorganic particles comprises inorganic particles having a median particle size of from 0.1 to 10 μ

m.

19. The method of claim 1, wherein the coating comprising inorganic particles is applied from a coating composition that further comprises a dispersant, a binder, an anti-cracking agent, an anti-foam agent, or combinations thereof.

20. The method of claim 1, which comprises applying the coating comprising inorganic particles to the modified inner channel surfaces by slip casting or flow coating.

21. The method of claim 1, which comprising firing the coated support to calcinate the organic pore-filling material, leaving a porous inorganic coating on the porous support.

22. The method of claim 1, which further comprises sintering the inorganic particles in the porous inorganic coating.

23. The method of claim 22, wherein the sintered porous inorganic coating has a thickness of from 1 to 25 μ

m throughout the length of the inner channels.

24. The method of claim 23, wherein the inner channels have a length of 80 mm or more.

25. The method of claim 22, wherein the sintered inorganic coating has a median pore size of from 0.1 to 2 μ

m.

26. A porous inorganic coating on a porous support, which is made by the method of claim 1.

27. A coated porous support, which comprises:

a porous support comprising a first end, a second end, and a plurality of inner channels having surfaces defined by porous walls having a median pore size of X μ

m and having a length extending through the support from the first end to the second end; and

a coating of inorganic particles having a median particle size of Y μ

m coating the surfaces of the inner channels of the provided porous support;

wherein the ratio X/Y≧

1; and

wherein the layer of inorganic particles provides a continuous coating throughout the circumference and length of the inner channels of the porous support.