Photocatalytic ozonation of dimethyl phthalate with TiO2 prepared by a hydrothermal method

TiO2 was prepared by a hydrothermal method at a low temperature and used to degrade and mineralize dimethyl phthalate (DMP). TiO2 was characterized by XRD, TEM, BET and UV-vis techniques. The characteristics of TiO2 prepared by a hydrothermal method (h-t TiO2) included a good crystalline anatase phase, greater surface area, stronger absorption to UV light wavelength and lower agglomeration than TiO2 prepared by a classic sol-gel method (s-g TiO2). The photocatalytic activity of h-t TiO2 prepared under optimal hydrothermal condition (180 °C for 10 h) was 2.5 times higher than that of s-g TiO2 in degrading DMP. The process of photocatalysis combined with UV irradiation and ozonation (TiO2/UV/O3) considerably improved the mineralization and degradation of DMP compared to photocatalysis combined with UV irradiation (TiO2/UV), ozonation combined with UV irradiation (UV/O3), and ozonation alone (O3). A kinetic study showed the mineralization in TiO2/UV/O3 followed the Langmuir-Hinshelwood model.