Catalytic filters for the abatement of volatile organic compounds

Catalytic filters were prepared by depositing a gamma-Al(2)O(3) layer on the pore walls of alpha-Al(2)O(3) filters by in situ precipitation (nitrate-urea method), followed by Pt dispersion via incipient wetness impregnation. The thereby obtained catalytic filters were tested, after characterisation (permeability assessment, BET measurement, SEM-EDAX observation, XRD analysis), in the catalytic combustion of selected volatile organic compounds (naphtalene, propylene, propane and methane), fed alone or in mixture. The VOCs conversion results, obtained by varying the operating temperature, the superficial velocity and the catalyst loading in the filter, showed that catalytic filters might outperform conventional technologies in the treatment of flue gases where simultaneous dust removal and catalytic abatement of VOCs have to be accomplished (municipal waste incinerators, wood combustion furnaces, etc.). On the grounds of a kinetics assessment study, a model, based on an isothermal pseudo-homogeneous approach, was also assembled and solved by the finite difference method, getting fair, though improvable, fitting of the experimental abatement data. (C) 1999 Elsevier Science Ltd. All rights reserved.