Photocatalytic oxidation and ozonation of catechol over carbon-black-modified nano-TiO_2 thin films supported on Al sheet

摘要

The photocatalytic activity of the carbon-black-modified nano-TiO_2 (CB-TiO_2) thin films was 1.5 times higher than that of TiO_2 thin films in degrading Reactive Brilliant Red X-3B. Photocatalytic oxidation and ozonation of catechol over CB-TiO_2 thin films supported on Al sheet was investigated. The experiments showed that ozone concentrations had an important effect on TOC removal. The combined photocatalysis with UV irradiation and ozonation (TiO_2/UV/O_3) process considerably increased TOC removal rate compared to combined photocatalysis with UV irradiation and oxygen oxidation (TiO_2/UV/O_2) process, ozonation alone (O_3) process, combined ozonation and UV irradiation (UV/O_3) process. The complete mineralization of catechol followed pseudo-zero-order kinetics dependent upon ozone (oxygen) concentration and indicated catechol concentration did not affect the kinetics dufing UV/O_3 and TiO_2/UV/O_3 (O_2) processes. The kinetic study showed that the rate constants in the complete mineralization of catechol with TiO_2/UV/O_3 are 1.32-1.80 times higher than that of UV/O_3 with the same concentration of ozone. The rate constants are 2.56-5.36 times higher than the maximal rate constants of TiO_2/UV/O_2 and 4.68-9.8 times higher than the maximal rate constants of TiO_2/UV.