Visible-Light-Induced Photocatalytic Degradation of PAH-Contaminated Soil and Their Pathways by Fe-Doped TiO₂ Nanocatalyst

The aim of the present study was to establish the photocatalytic efficiency of Fe-doped TiO₂ nanocatalysts toward polycyclic aromatic hydrocarbons (PAHs), which were phenanthrene, anthracene, and fluoranthene, contaminated soil under visible irradiation. The morphology, phase, and particle size of the prepared nanocatalyst have been studied as a first mention in literature. The photoresponse of the TiO₂ extends from UV region to the visible region was proved by the diffuse reflectance spectrophotometry (DRS). The surface area is greatly increased though the Fe-doped TiO₂ compared with the bare TiO₂. The pH value of the media showed the beneficial to PAH absorption on the Fe-doped TiO₂ under the alkaline condition due to the surface catalyst possesses much negative charge, which is increase in percentage of PAH degradation. Based on GC-MS study, the mechanism of photoactivity of the selected PAHs involves hydroxylation, ring opening, and rearrangement reactions. The main intermediates of PAH photodegradation were found to be 9-octadecanoic acid, heptadecane, octadecane, cyclohexane (1-hexadecylheptadecyl), and 15-hydroxypentadecanoic acid.