Use of manganese oxide and activated carbon fibers for removing a particle, volatile organic compound or ozone from a gas

• US 9,427,728 B2
• Filed: 11/27/2013
• Issued: 08/30/2016
• Est. Priority Date: 06/03/2011
• Status: Expired due to Fees

• Current Assignee: Regents of the University of California (University of California)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Sidheswaran, Meera A., Destaillats, Hugo, Fisk, William J.
• Primary Examiner(s): Hoban, Matthew E
• Assistant Examiner(s): FIORITO, JAMES A
• Application Number:
  US14/092,829
• Publication Number:
  US 20140255283A1
• Time in Patent Office: 1,007 Days
• Field of Search: 423/245.1, 423/605, 502/324, 502/416, 422/122
• US Class Current: 1/1
• CPC Class Codes: A61L 9/00 Disinfection, sterilisation or deodorisation of air body deodorants A61Q15/00; purifying air by respirators A62B, A62D9/00; separating dispersed particles from gases or vapours B01D45/00 - B01D51/00, B03C3/00; chemical or biological purification of waste gases B01D53/34; production of ozone C01B13/10; air-conditioning systems incorporating sterilisation F24F3/16, F24F8/20
• CPC Class Codes: B01D 2253/102 Carbon
• CPC Class Codes: B01D 2255/2073 Manganese
• CPC Class Codes: B01D 2257/106 Ozone
• CPC Class Codes: B01D 2257/708 Volatile organic compounds V.O.C.'s
• CPC Class Codes: B01D 53/8668 Removing organic compounds not provided for in B01D53/8603 - B01D53/8665
• CPC Class Codes: B01J 20/20 comprising free carbon; comprising carbon obtained by carbonising processes
• CPC Class Codes: B01J 21/18 Carbon
• CPC Class Codes: B01J 23/34 Manganese
• CPC Class Codes: B01J 35/30 characterised by their physical properties
• CPC Class Codes: B01J 35/393 Metal or metal oxide crystallite size
• CPC Class Codes: B01J 35/40 characterised by dimensions, e.g. grain size in a colloidal state B01J35/23; crystallite size B01J35/77
• CPC Class Codes: B01J 35/56 Foraminous structures having flow-through passages or channels, e.g. grids or three-dimensional monoliths
• CPC Class Codes: B01J 35/58 Fabrics or filaments
• CPC Class Codes: B01J 35/612 less than 10 m2/g
• CPC Class Codes: B01J 35/615 100-500 m2/g
• CPC Class Codes: B01J 35/617 500-1000 m2/g
• CPC Class Codes: B01J 35/618 more than 1000 m2/g
• CPC Class Codes: B01J 37/0215 Coating
• CPC Class Codes: B01J 37/031 Precipitation
• CPC Class Codes: B01J 37/08 : Heat treatment B01J37/0009, B01J37/0018 take precedence
• 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: Y02A 50/20 : Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters

Abstract

The present invention provides for a device for reducing a volatile organic compound (VOC) content of a gas comprising a manganese oxide (MnO_x) catalyst. The manganese oxide (MnO_x) catalyst is capable of catalyzing formaldehyde at room temperature, with complete conversion, to CO₂ and water vapor. The manganese oxide (MnO_x) catalyst itself is not consumed by the reaction of formaldehyde into CO₂ and water vapor. The present invention also provides for a device for reducing or removing a particle, a VOC and/or ozone from a gas comprising an activated carbon filter (ACF) on a media that is capable of being periodically regenerated.

Claims

1. A method for reducing formaldehyde content of a gas, comprising:

at room temperature, contacting the formaldehyde-containing gas with a manganese containing catalyst consisting essentially of nsutite and cryptomelane particles having a Brunner Emmet and Teller (BET) surface area of at least 100 m² g<sup>−

1</sup>, thereby obtaining a gas having a reduced formaldehyde content as compared to the gas before contacting it with the manganese containing catalyst.

2. The method of claim 1, wherein the manganese containing catalyst is a mixture of about 95% nsutite and about 5% cryptomelane.

3. The method of claim 2, wherein the manganese containing catalyst particles have crystallite sizes of about 4 to 10 nm.

4. The method of claim 3, wherein the manganese containing catalyst is a powder comprised of nanospherical particles with diameter smaller than 50 nm.

5. The method of claim 4, wherein the nanospherical particles are monodisperse.

6. The method of claim 4, wherein the nanospherical particles are porous.

7. The method of claim 1, wherein the manganese containing catalyst is formed by a method comprising:

providing a manganese salt and a permanganate salt solution wherein the molar ratio of the permanganate to manganese salt has a ratio of about 2;

3,

forming a black suspension comprising a precipitate,

separating the precipitate from the solution,

optionally, washing the precipitate,

heating the precipitate to form the manganese containing catalyst, and

optionally, converting the precipitate into a powder.

8. The method of claim 1, wherein the manganese containing catalyst is comprised in a composition coated on a building or structure.

9. The method of claim 8, wherein the composition is a paint.

10. The method of claim 1, further comprising flowing the gas at a face velocity of about 0.002 to 0.5 m s⁻

1 through a device for reducing the formaldehyde content of the gas, wherein the device comprises the manganese containing catalyst applied to an air filter.

11. The method of claim 10, wherein the air filter is a fibrous particle filter.