SURFACES AND COATINGS FOR THE REMOVAL OF CARBON DIOXIDE

• US 20090026063A1
• Filed: 07/25/2007
• Published: 01/29/2009
• Est. Priority Date: 07/25/2007
• Status: Active Grant

• Current Assignee: Howmet Aerospace, Inc.
• Original Assignee: Alcoa Incorporated (Howmet Aerospace, Inc.)
• Inventors: Askin, Albert L., Espinoza-Nava, Luis H., Xu, Weizong, Skiles, Jean Ann, Barrage, Lori A., Davis, Carroll D., Speer, Robert J., Kolek, Paula L., Bergstrom, Verne
• Granted Patent: US 7,910,220 B2
• Time in Patent Office: Days
• US Class Current: 204/157.300
• CPC Class Codes: B01D 2255/20707 Titanium
• CPC Class Codes: B01D 2255/802 Photocatalytic
• CPC Class Codes: B01D 2257/504 Carbon dioxide
• CPC Class Codes: B01D 53/62 Carbon oxides
• CPC Class Codes: B01D 53/864 Removing carbon monoxide or hydrocarbons
• CPC Class Codes: B01D 53/88 Handling or mounting catalysts
• CPC Class Codes: B01J 35/004 Photocatalysts
• CPC Class Codes: B01J 35/39 Photocatalytic properties
• CPC Class Codes: C08K 3/22 of metals
• CPC Class Codes: C09D 1/00 Coating compositions, e.g. paints, varnishes or lacquers, based on inorganic substances
• CPC Class Codes: C09D 7/61 inorganic
• CPC Class Codes: C09D 7/67 Particle size smaller than 100 nm
• CPC Class Codes: C09D 7/68 Particle size between 100-1000 nm
• CPC Class Codes: Y02C 20/40 of CO2
• CPC Class Codes: Y02P 20/151 Reduction of greenhouse gas [GHG] emissions, e.g. CO2

Abstract

Apparatus suited for removing carbon dioxide from gases are disclosed. The apparatus may employ bodies having a photocatalytic film. Associated methods and compositions are also disclosed.

Claims

1. A mixture comprising:

a solvent;

semiconductor particles dispersed within the solvent, the semiconductor particles having an average particle size of not greater than 500 nanometers;

a film former dispersed within the solvent, wherein the film former is capable of forming an amorphous film upon application to a substrate; and

a charge transfer material dispersed within the solvent;

wherein the mixture comprises a ratio of semiconductor particles to charge transfer material of at least about 1;

1.

2. The mixture of claim 1, wherein the semiconductor particles comprise titanium dioxide.

3. The mixture of claim 2, wherein the charge transfer material comprises an alkali element.

4. The mixture of claim 3, wherein the alkali element is sodium.

5. The mixture of claim 3, wherein the charge transfer material comprises an alkali salt.

6. The mixture of claim 3, wherein the alkali salt is sodium hydroxide.

7. The mixture of claim 1, wherein the film former comprises an acid.

8. The mixture of claim 1, wherein the film former comprises peroxotitanic acid.

9. The mixture of claim 1, wherein the mixture comprises a ratio of semiconductor particles to charge transfer material of at least about 1.5:

1.

10. The mixture of claim 1, further comprising:

a pollution attraction agent dispersed within the solvent.

11. The mixture of claim 10, wherein the pollution attraction agent comprises a silicate-containing mineral.

12. The mixture of claim 10, wherein the pollution attraction agent comprises a phosphate-containing mineral.

13. A photocatalytic film comprising:

a matrix;

semiconductor particles within the matrix; and

a charge transfer agent within the matrix, wherein the photocatalytic film is capable of removing at least about 10 ppm/minute CO₂ gas from a gas stream comprising 1% vol. CO₂ per square meter of photocatalytic film surface area.

14. The photocatalytic film of claim 13, wherein the ratio of semiconductor particles to charge transfer agent is at least about 1:

1.

15. The photocatalytic film of claim 13, wherein the matrix comprises amorphous titanium dioxide, wherein the semiconductor particles comprise titanium dioxide, and wherein the charge transfer agent comprises an alkaline material.

16. The photocatalytic film of claim 15, wherein the alkaline material comprises sodium.

17. The photocatalytic film of claim 13, further comprising:

a pollution attraction agent.

18. A body comprising:

a substrate;

the photocatalytic film disposed on the substrate; and

a receptor layer in communication with the photocatalytic film, wherein the body is capable of removing at least about 10 ppm/minute CO₂ gas from a gas stream comprising 1 vol. % CO₂ per square meter of photocatalytic film surface area.

19. The body of claim 18, wherein the photocatalytic film comprises:

a matrix;

semiconductor particles within the matrix; and

a charge transfer agent within the matrix.

20. The body of claim 18, wherein the substrate comprises aluminum.

21. The body of claim 20, wherein the substrate is selected from the group consisting of aluminum alloys and aluminum foams.

22. The body of claim 21, further comprising:

an organic layer between the substrate and the photocatalytic film.

23. The body of claim 22, further comprising:

a barrier layer between the photocatalytic film and the organic layer.

24. A body comprising:

a substrate;

a photocatalytic film disposed on the substrate, wherein the photocatalytic film comprises;

an amorphous matrix comprising titanium dioxide;

titanium dioxide particles dispersed in the amorphous matrix; and

an alkaline material dispersed in the amorphous matrix

a receptor layer between the substrate and the photocatalytic film, wherein the receptor layer comprises a receptor agent;

wherein the body is capable of removing at least about 10 ppm/minute CO₂ gas from a gas stream comprising 1 vol. % CO₂ per square meter of photocatalytic film surface area.

25. The body of claim 24, wherein the alkaline material comprises sodium.

26. The body of claim 25, wherein the receptor agent comprises calcium.

27. The body of claim 26, further comprising:

a pollution attraction agent within the amorphous matrix of the photocatalytic film.

28. The body of claim 27, wherein the substrate comprises aluminum.

29. The body of claim 28, wherein the substrate is selected from the group consisting of aluminum alloys and aluminum foams.

30. The body of claim 29, further comprising:

an organic layer between the substrate and the photocatalytic film.

31. The body of claim 30, further comprising:

a barrier layer between the photocatalytic film and the organic layer.

32. The body of claim 24, wherein the substrate is a photovoltaic cell.

33. The body of claim 24, wherein the substrate predominantly comprises a non-metal.

34. A method comprising:

contacting a body comprising a photocatalytic film with a carbon dioxide-containing gas, wherein the photocatalytic film comprises;

a matrix;

semiconductor particles within the matrix; and

a charge transfer agent within the matrix; and

converting, via the body, at least 10 ppm/minute carbon dioxide to non-carbon dioxide products per square meter of photocatalytic film surface area.

35. The method of claim 34, wherein the converting step comprises:

reacting, in the presence of light, carbon dioxide gas with at least one of the semiconductor material and the charge transfer agent to produce a non-carbon dioxide product.

36. The method of claim 34, wherein the converting step occurs at about ambient conditions.

37. The method of claim 36, wherein the converting step comprises:

producing a carbonate-containing end product via a receptor agent.

38. The method of claim 34, wherein the charge transfer agent comprises a first alkaline material and wherein the receptor agent comprises a second alkaline material, different than the first alkaline material.

39. The method of claim 38, wherein the first alkaline material comprises sodium and the second alkaline material comprises calcium.

40. A method comprising:

flowing an incoming gas stream comprising carbon dioxide through a gas scrubbing apparatus comprising a photocatalytic film, wherein the photocatalytic film comprises;

a matrix;

semiconductor particles within the matrix; and

a charge transfer agent within the matrix; and

removing, via the photocatalytic film, at least 10 ppm/minute carbon dioxide from the incoming gas stream.

41. The method of claim 40, wherein carbon dioxide is removed from the incoming gas stream at a rate of at least about 0.5 vol. % per hour.

42. The method of claim 40, wherein the flowing and producing steps occur at about ambient conditions.

43. The method of claim 42, comprising:

discharging an effluent gas stream from the gas scrubbing apparatus, wherein the concentration of carbon dioxide in the effluent gas stream is at least about 1% less than the concentration of carbon dioxide in the incoming gas stream.

44. The method of claim 43, wherein the concentration of carbon dioxide in the effluent gas stream is at least about 5% less than the concentration of carbon dioxide in the incoming gas stream.

45. A body comprising:

a substrate having a surface area of at least about 1 m²/gram; and

a photocatalytic layer disposed on the substrate;

wherein the substrate is capable of removing at least about 10 ppm/minute carbon dioxide from a gas comprising 1 vol. % carbon dioxide.

46. The body of claim 45, wherein the substrate comprises alumina.

47. The body of claim 45, wherein the substrate is in tabular form.

48. The body of claim 45, wherein substrate is in granular form.

49. The body of claim 45, wherein the substrate is in particulate form.

50. The body of claim 45, wherein the substrate comprises carbon.

51. A gas scrubbing apparatus comprising:

a gas entrance;

a gas exit; and

a plurality of bodies located between the gas entrance and the gas exit, wherein at least some of the bodies comprise a photocatalytic film and a receptor agent, and wherein the substrate is capable of removing at least about 10 ppm/minute carbon dioxide from a gas comprising 1 vol. % carbon dioxide.

52. The apparatus of claim 51, wherein at least some of the bodies have a surface area of at least about 1 m²/gram.

53. The apparatus of claim 51, wherein the gas scrubbing apparatus is a packed bed.

54. The apparatus of claim 51, wherein the gas scrubbing apparatus is a fluidized bed.

55. The apparatus of claim 51, wherein the gas scrubbing apparatus is a rebreather.

56. The apparatus of claim 51, wherein the gas scrubbing apparatus is a filter.