Use of manganese oxide and activated carbon fibers for removing a particle, volatile organic compound or ozone from a gas
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 CO 2 and water vapor. The manganese oxide (MnO x ) catalyst itself is not consumed by the reaction of formaldehyde into CO 2 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.
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 m 2 g −1 , 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.