Abstract: Titanium dioxide/activated carbon composite photocatalysts were prepared through hydrothermal treatment of titanium dioxide and activated carbon. In a recirculating photocatalytic reactor, the degradation of low concentration butyraldehyde, a gaseous pollutant, over the catalyst was performed. Based on the Langmuir-Hindshelwood equation and some hypotheses, a transient model for the degradation of the butyraldehyde in the recirculating reaction system was proposed. The results obtained from the kinetic model were approximately consistent with the experimental data. This indicated that the photodegradation behavior of gaseous pollutants could be well predicted using the kinetic model.

Key words: photocatalyst, titanium dioxide, activated carbon, gaseous pollutant, butyraldehyde, degradation, reaction kinetic model