Efficiently Synthetic TiO2 Nano-sheets for PCE, TCE, and TCA Degradations in Aqueous Phase Under VUV Irradiation

The present study investigates the applicability of the synthesized titanium dioxide (TiO2) for the removal of tetrachloroethene (PCE), trichloroethene (TCE), and 1,1,1-trichloroethane (TCA) in aqueous phase under VUV illumination. The photo-degradation results indicated that these harmful chemicals can be effectively removed under VUV irradiation, and the addition of the synthesized TiO2 significantly enhanced their degradation. Moreover, using nitrobenzene (NB) as a probe of hydroxyl radical (·OH), the NB degradation rate was better over VUV/synthesized TiO2, suggesting the high concentration of OH generated. The TiO2 used has been synthesized by a simple hydrothermal solution containing tetrabutyl titanate and hydrofluoric acid and characterized by using X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), transmission electron microscopy (TEM), and X-ray photo-electron spectroscopy (XPS). The characterization results showed that the synthesized TiO2 was in anatase form and consisted of well-defined sheet-shaped structures having a rectangular outline with a thickness of ~4 nm, side length of ~50 nm, and width of ~33 nm and has a surface of 90.3 m2 g−1. XPS analysis revealed the formation of ≡ Ti–F surface bonds. Moreover, the synthesized TiO2 nano-sheets have shown good stability after testing their photo-catalytic activity through five cycles of reuse in TCE degradation. In summary, it can be concluded from the results on both photo-catalytic activity and the surface analyses that the synthesized TiO2 nano-sheets have a great potential for application in chlorinated solvent-contaminated groundwater remediation.