Apparatus and process for air cleaning

• US 7,381,244 B2
• Filed: 08/03/2005
• Issued: 06/03/2008
• Est. Priority Date: 08/03/2005
• Status: Expired due to Fees

• Current Assignee: Air Products and Chemicals Incorporated (Linde Plc)
• Original Assignee: Air Products and Chemicals Incorporated (Linde Plc)
• Inventors: Farris, Thomas Stephen, Furlan, Wayne Robert, Tyndall, Daniel Warren, Golden, Timothy Christopher, Rabasco, John Joseph, Taylor, Fred William
• Primary Examiner(s): LAWRENCE JR, FRANK M
• Application Number:
  US11/196,070
• Publication Number:
  US 20070028770A1
• Time in Patent Office: 1,035 Days
• Field of Search: 951/16, 951/17, 951/39, 951/40, 951/43, 959/02, 55D/IG.9, 961/21, 961/32, 961/31, 961/53, 423/210, 423/219, 423/247, 423/249, 502/60, 502/79, 588/1, 588/2, 588 13- 15
• US Class Current: 95/116
• CPC Class Codes: A61L 9/16 using physical phenomena
• CPC Class Codes: B01D 2253/104 Alumina
• CPC Class Codes: B01D 2253/106 Silica or silicates
• CPC Class Codes: B01D 2253/108 Zeolites
• CPC Class Codes: B01D 2257/106 Ozone
• CPC Class Codes: B01D 2257/11 Noble gases
• CPC Class Codes: B01D 2257/50 Carbon oxides
• CPC Class Codes: B01D 2257/708 Volatile organic compounds V.O.C.'s
• CPC Class Codes: B01D 2257/80 Water
• CPC Class Codes: B01D 2257/91 Bacteria; Microorganisms
• CPC Class Codes: B01D 2259/40083 Regeneration of adsorbents in processes other than pressure or temperature swing adsorption
• CPC Class Codes: B01D 2259/40086 by using a purge gas B01D2259/4009 takes precedence
• CPC Class Codes: B01D 2259/4009 using hot gas
• CPC Class Codes: B01D 2259/4146 Contiguous multilayered adsorbents
• CPC Class Codes: B01D 2259/4508 for cleaning air in buildings
• CPC Class Codes: B01D 53/0462 Temperature swing adsorption
• CPC Class Codes: B01D 53/047 Pressure swing adsorption
• CPC Class Codes: 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
• CPC Class Codes: B01D 53/8675 Ozone
• CPC Class Codes: F24F 8/70 by removing radon
• CPC Class Codes: G21F 9/02 : Treating gases
• CPC Class Codes: Y10S 95/902 : Molecular sieve

Abstract

A process and an apparatus for removal of radon from indoor air. The process having the step of contacting indoor air with an adsorbent, that is a silver-exchanged zeolite. The apparatus for the removal of radon from indoor air comprises a silver exchanged zeolite.

Claims

1. A process for removal of radon from indoor air comprising the step of contacting said indoor air with adsorbent, said adsorbent comprising a silver-exchanged zeolite.

2. The process of claim 1 wherein the radon level within said indoor air is at least 2 pCi/l.

3. The process of claim 1 wherein the radon level within said indoor air is at least 4 pCi/l.

4. The process of claim 1 further comprising the step of removing moisture from said indoor air prior to said contacting step.

5. The process of claim 1 wherein the zeolite is selected from the group consisting of zeolite A, zeolite X, zeolite LSX, zeolite Y, mordenite, chabazite, clinoptilite, erionite, ferrierite, zeolite L and offretite.

6. The process of claim 1 wherein the silver-exchanged zeolite is also exchanged with lithium.

7. The process of claim 1 wherein the silver-exchanged zeolite is silver/lithium-exchanged zeolite having an ion exchange composition of the form Li_xAg_yM_z where 0.85≦

x+y≦

1, 0.2≦

y≦

0.7, and 0≦

z≦

0.15 with M representing one or more cations, and x, y, and z representing fractions of total exchangeable sites in the zeolite.

8. The process of claim 7 wherein M is a cationic form of one or more elements selected from the group consisting of Na, K, Cs, Mg, La, Ce, Ca, Al, and Zn.

9. The process of claim 7 wherein the zeolite is zeolite X.

10. The process of claim 4 wherein said step of removing said moisture from said indoor air is performed by contacting said indoor air with adsorbent.

11. The process of claim 10 wherein said adsorbent for said removing step is alumina, silica gel, zeolite or mixtures thereof.

17. The process of claim 1 further comprising the step of contacting said air with adsorbent capable of removing hydrocarbons from said air prior to said contacting said silver-exchanged zeolite.

18. The process of claim 1 further comprising the step of contacting said air with adsorbent capable of removing ozone from said air prior to said contacting said silver-exchanged zeolite.

19. The process of claim 1 further comprising prior to said contacting of said silver-exchanged zeolite step, the steps of:

contacting said air with adsorbent capable of removing moisture from said air, contacting said air with adsorbent capable of removing hydrocarbons from said air, and contacting said air with adsorbent capable of removing ozone from said air.

20. The process of claim 1 further comprising prior to said contacting of said silver-exchanged zeolite step, the steps of:

contacting said air with adsorbent for removing moisture from said air comprising a material selected from the group consisting of alumina, silica gel, zeolite and mixtures thereof;

contacting said air with adsorbent for removing hydrocarbons from said air comprising a material selected from the group consisting of activated carbon, silica gel, alumina and high Si/Al ratio zeolites; and

contacting said air with adsorbent comprising a material selected from the group consisting of hopcalite (CuO/MnO mixture), noble metal catalysts, activated carbon, zeolites, silica gel, hydrotalcite, clays and alumina for removing ozone from said air.

21. The process of claim 20 further wherein the silver-exchanged zeolite for removal of said radon is silver/lithium-exchanged zeolite having an ion exchange composition of the form Li_xAg_yM_z where 0.85≦

x+y≦

1, 0.2≦

y≦

0.7, and 0≦

z≦

0.15 with M representing one or more cations, and x, y, and z representing fractions of total exchangeable sites in the zeolite.

12. A process for the removal of impurities from indoor air contaminated with radon within a building comprising the steps of;

contacting the indoor air steam with porous material which releases silver ions upon contact with water for removing bacteria and molds;

contacting the indoor air with desiccant under conditions for removing moisture; and

,

contacting the indoor air with silver exchanged zeolite capable of removing radon.

13. The process of claim 12 further comprising the step of contacting the indoor air with adsorbent capable of removing ozone after said contacting with said dessicant step.

14. The process of claim 13 further comprising the step of contacting the indoor air with adsorbent capable of removing volatile organics or carbon oxides prior to said contacting step for removing radon.

15. The process of claim 14, wherein the silver exchanged zeolite for removing radon is selected from the group consisting of zeolite A, zeolite X, zeolite LSX, zeolite Y, mordenite, chabazite, clinoptilite, erionite, ferrierite, zeolite L, and offretite.

16. The process of claim 14 wherein the silver exchanged zeolite for removing radon is also exchanged with lithium.