Environmental catalysis and materials
Efficient dechlorination of chlorinated solvent pollutants under UV irradiation by using the synthesized TiO2 nano-sheets in aqueous phase
Landry Biyoghe Bi Ndong
Murielle Primaelle Ibondou
Serge Maurice Mbadinga
Received July 03, 2013,Revised November 08, 2013, Accepted , Available online April 01, 2014
Volume 26,2014,Pages 1188-1194
Titanium dioxide (TiO2), which is the widely used photo-catalyst, has been synthesized by simple hydrothermal solution containing tetrabutyl titanate and hydrofluoric acid. The synthesized product has been applied to photo-degradation in aqueous phase of chlorinated solvents, namely tetrachloroethene (PCE), trichloroethene (TCE) and 1,1,1-trichloroethane (TCA). The photo-degradation results revealed that the degradation of these harmful chemicals was better in UV/synthesized TiO2 system compared to UV/commercial P25 system and UV only system. The photo-catalytic efficiency of the synthesized TiO2 was 1.4, 1.8 and 3.0 folds higher compared to the commercial P25 for TCA, TCE and PCE degradation, respectively. Moreover, using nitrobenzene (NB) as a probe of hydroxyl radical (·OH), the degradation rate was better over UV/synthesized TiO2, suggesting the high concentration of ·OH generated in UV/synthesized TiO2 system. In addition, ·OH concentration was confirmed by the strong peak displayed in EPR analysis over UV/synthesized TiO2 system. The characterization result using XRD and TEM 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 a surface 90.3 m2/g. XPS analysis revealed that =Ti-F bond was formed on the surface of the synthesized TiO2. The above results on both photo-catalytic activity and the surface analysis demonstrated the good applicability of the synthesized TiO2 nano-sheets for the remediation of chlorinated solvent contaminated groundwater.
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