PREPARATION OF TiO2 CALCINED AT VARIOUS TEMPERATURES AND PHOTOLYSIS OF 2-CHOROBENZOIC ACID

In order to investigate the influence of calcination temperature on the structure and photocatalytic activity of TiO2， nanometer titania photocatalysts have been prepared with sol-gel technique by using dibutyl phthalate as the precursor． Methylene blue was used to evaluate photocatalytic activity of TiO2 ． TG analysis results showed that the phase transition from anatase to rutile occurred during the temperature range of 450 ～ 700 ℃． XrD analysis results demonstrated that TiO2 crystal structure was affected by temperature obviously． TiO2 anatase crystal structure could be obtained in 450 ～ 600 ℃，and TiO2 rutile crystal structure occurred at 650 ℃． Photocatalytic degradation of methylene blue test described that calcination temperature had a great influence on TiO2 photocatalytic activity． Using TiO2 calcined at 450 ～ 600 ℃，the methylene blue photodegradation rate could reach 95% ～ 97% after 2. 5 h． The 2-chlorobenzoic acid photodegradation rate could reach 80% after 6 h using TiO2 calcined at 550 ℃，and the photodegradation process agreed to zero-roder reaction kinetics model．