Catalytic filters for the abatement of volatile organic compounds

Catalytic filters were prepared by depositing a gamma-Al2O3 layer on the po re walls of alpha-Al2O3 filters by in situ precipitation (nitrate-urea meth od), followed by Pt dispersion via incipient wetness impregnation. The ther eby obtained catalytic filters were tested, after characterisation (permeab ility 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 conver sion results, obtained by varying the operating temperature, the superficia l velocity and the catalyst loading in the filter, showed that catalytic fi lters might outperform conventional technologies in the treatment of flue g ases where simultaneous dust removal and catalytic abatement of VOCs have t o 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 th e finite difference method, getting fair, though improvable, fitting of the experimental abatement data. (C) 1999 Elsevier Science Ltd. All rights res erved.