Patent ID: 6319484
Filing Date: 2001-11-20
Classification: B01D,F24C

Abstract:
A composition for abatement of gas-borne volatile organic compounds (""VOCs"") comprises: (a) a protective adsorbent selected from the group consisting of zeolites having a minimum pore aperture of at least about 6.5 .ANG.ngstroms an d which are effective, within an adsorption temperature range, (i) to adsorb first VOCs and (ii) to pass therethrough second VOCs of smaller molecular dimensions than the first VOCs, but excluding from the group zeolites containing one or both of silver and copper cations in amounts effective to enhance adsorption of the second VOCs on the protective adsorbent; (b) a second adsorbent selected from the group consisting of one or more of silver-containing zeolites and copper-containing Y zeolite and effective, within the adsorption temperature range, to adsorb, at least in the absence of moisture, the second VOCs; (c) a catalytically effective amount of a protective oxidation catalyst disposed relative to the protective and second adsorbents so as to contact and, under oxidation conditions defined below, promote the oxidation of first VOCs prior to the first VOCs' contacting the second adsorbent; and (d) a second oxidation catalyst intimately intermingled with the second adsorbent, and present in an amount effective to promote, under the oxidation conditions, oxidation of second VOCs retained on the second adsorbent, the intermingled second oxidation catalyst and second adsorbent being disposed to contact the effluent from the protective adsorbent and protective oxidation catalyst;the oxidation conditions comprising an oxidation temperature range which is hotter than the adsorption temperature range, and both the adsorption and oxidation temperature ranges lying in an operating temperature range of between about 20 to 500.degree. C.