PHOTOCATALYTIC KINETICS OF GASEOUS ACETALDEHYDE DEGRADATION ON LOW INTENSITY ULTRA VIOLET IRRADIATED TiO2

Abstract

PHOTOCATALYTIC KINETICS OF GASEOUS ACETALDEHYDE DEGRADATION ON LOW INTENSITY ULTRA VIOLET IRRADIATED TiO 2 . The kinetics of photocatalytic degradation of gaseous acetaldehyde with semiconductor catalyst TiO 2 was studied. The experiment was carried out using TiO 2 photocatalyst prepared from titanium tetrachloride (TiCl 4 ) and titanium(lV) isoproxide (Ti(OPr) 4 ) as the starting materials. Comercially available highly active TiO 2 from Merck was used for purposes ofcomparison The TiO 2 films were prepared on soda lime plates and an SiO 2 -coated soda lime plate using sol-gel method and dip-coating techniques The photocatalytic kinetics of the catalysts were assessed by measuring the photodegradative oxidation of gaseous acetaldehyde at various initial concentrations, UV intensities, and shapes of catalyst. The Merck powder shown the highest photocatalytic activity. All reactions proceeded with approximately first-order reaction kinetics (as indicated from the linear transforms ln(C 0 /C) as function of irradiation time), especially for the relatively low initial concentration. Meanwhile, at high initial concentration of acetaldehyde, photocatalytic reactions occurred with approximately zero-order kinetics. TiO 2 film photocatalyst supported on soda lime plate shown lower photocatalytic activity than the powder one, however, when the films were coated on SiO 2 -coated soda lime plate, photocatalytic activity of the resulting film increased and even higher than that of the powder form.