Photocatalytic Decomposition Of Gaseous Toluene By TiO2 Nanoparticles Coated On Activated Carbon

Volatile organic compounds are considered as a group of major environmental pollutants and toluene is recognized as one of the representatives. In this research, the photocatalytic activity for toluene removal was studied over TiO₂ nanoparticles embeded on activated carbon. Laboratory-scale experiments were conducted in a fixed-bed reactor equipped with 4 w and 8 w UV lamps (peak wavelength at 365 nm) to determine the oxidation rates of toluene. The photocatalyst was extensively characterized by means of Xray diffraction and scan electronmicroscopy. Experiments were conducted under general laboratory temperature (25ºC±2) while the irradiation was provided by the UV lamps. The dependence of the reaction rate on light intensity as well as the deactivation of the catalyst were determined. The results indicated that the rate of the photocatalytic process increased with increasing the intensity of UV irradiation. Using the UV-A lamps, the decomposition rate of toluene was 98%. The stabilized photocatalyst presented remarkable stability (no deactivation and excellent repeatability). The catalyst could be regenerated by UV irradiation in the absence of gas phase. The control experiments confirmed that the photocatalytic effects of toluene onto the TiO₂ /activated carbon catalysts in the dark conditions were negligible. Reproducibility tests proved that the photocatalytic activity of the photocatalyst remains intact even after several experiments of new added toluene quantities. The study demonstrated that the TiO₂ /activated carbon catalyst may be a practical and promising way to degrade the toluene under ultraviolet irradiation.

Keywords
Toluene, TiO₂ nanoparticles, activated carbon, photocatalytic, coating