Preparation And Characterization Of Doped TiO₂ For Photocatalytic Treatment Of TNT Red Water

Photocatalysis, as one of the most popular technologies for controlling environmental pollution, has received more and more attention. Now, TiO2 has become one of the most common photocatalysts due to its various merits, such as non-toxicity, photo stability, chemical stability, and low-cost. Although it has been widely investigated in the past decade, some problems such as the low photo-quantum efficiency and low photocatalytic activity under visible light still render its practical application.Therefore, some modifications of TiO2 were adopted in this dissertation. First, TiO2 and single-doping samples (Fe-doped TiO2, N-doped TiO2 and S-doped TiO2) were prepared with peroxotitanium complex (PTC) as a precursor by a low-temperature process. Second, co-doping sanples (Fe-N-doped TiO2, Fe-S-doped TiO2 and Fe-N-S-doped TiO2) were prepared by a modified sol-gel method with Fe3+ doping peroxotitanium (Fe-PTC) as a precursor by a low-temperature process. The structure and properties of catalysts were characterized by XRD, FT-IR, UV-Vis respectively, where XRD represents all doped TiO2 species are classified into anatase pattern. And FT-IR verifies that the positions of Ti4+ in crystal lattice are replaced by Fe3+ and O in crystal lattice are replaced by N or S. UV-Vis diffuse reflectance spectroscopy result showed that a red-shift and an enhanced absorption in the visible region were observed in all the prepared samples.Finally, the photocatalytic properties of different products were assessed by degradation of 2,4,6-trinitotoluene in red water. And results reveal that the co-doping can remarkably alter the photocatalytic activity than single-doping. N-TiO2 exhibited the highest photocatalytic activity in all the single-doping TiO2 species and Fe-N-S-doped TiO2 exhibited highest photocatalytic activity in all the co-doping TiO2 species. After 12h irradiated under the visible light, the photocatalytic degradation rate of TNT by co-doped TiO2 reached to 91.5%, which is almost twice of pure TiO2.