Removal of Aromatic Hydrocarbon Pollutants Using Visible Light-Activated Titania Codoped with Nitrogen and Iron
N- and Fe-codoped TiO2 composites (N-Fe-TiO2) with different mixing proportions were synthesized using a facile sol-gel process, and the improvement in their performance was evaluated for the decomposition of gaseous monocyclic aromatic hydrocarbons under visible light illumination. The synthesized samples were characterized using X-ray diffraction techniques, energy-dispersive X-ray analysis, Fourier transform infrared spectroscopy, and UV-visible spectroscopy. The photocatalytic activity of two N-Fe-TiO2 samples with suitable TiO2:N:Fe proportions were superior to those of N doped TiO2 (N-TiO2) samples, which were in turn higher than those of pure TiO2. Specifically, the average decomposition efficiencies of N-Fe-TiO2-0.1 for benzene, toluene, ethyl benzene, and o-xylene were 25%, 82%, 97%, and ~100%, respectively, while the respective values for N-TiO2 were 19%, 52%, 73%, and 78%. In addition, the average efficiencies of pure TiO2 were ~0%, 4%, 13%, and 32%, respectively. The photocatalytic activity of the N-Fe-TiO2 samples increased as the Fe contents decreased, while it increased with increasing retention time. However, the reaction rates of benzene, toluene, ethyl benzene, and o-xylene decreased, as the retention time increased. Over all, the N-Fe-TiO2 composites with optimal mixing proportions could be efficiently applied for the degradation of monocyclic aromatic hydrocarbons under visible light illumination.
Keywords - Gas phase, Optimal ratio, N,Fe-Doped, Degradation rate.