Photocatalytic ozonation of dibutyl phthalate over TiO_2 film

摘要

A novel carbon black modified nano-TiO_2 film photocatalyst (CB-TiO_2) was prepared by a sol-gel method and used for degrading and mineralizing dibutyl phthalate.The film was characterized by XRD,SEM,and DRS techniques.Carbon black modification could make TiO_2 film more pores,looser structure,smaller crystal sizes and longer excitation wavelength.The photocatalytic activity of the CB-TiO_2 films was 1.4 times higher than that of TiO_2 films in degrading dibutyl phthalate.The results showed that ozone concentrations had an important effect on degradation and mineralization of dibutyl phthalate.The combined photocatalysis with UV irradiation and ozonation (TiO_2/UV/O_3) process considerably improved mineralization and degradation of dibutyl phthalate compared to combined photocatalysis with UV irradiation (TiO_2/UV) process,combined ozonation with UV irradiation (UV/O_3) process and ozonation alone (O_3) process.Dibutyl phthalate can be quickly mineralized in TiO_2/UV/O_3 and UV/O_3,its mineralization followed pseudo-zero-order kinetics dependent upon ozone concentration and indicated its concentration did not affect the kinetics during TiO_2/UV,UV/O_3 and TiO_2/UV/O_3 processes.The kinetic study showed the mineralization rate constants of dibutyl phthalate with TiO_2/UV/O_3 are 1.2-1.8 times higher than that of UV/O_3 with the same ozone concentration and 3.5 times higher than that of TiO_2/UV.