Abstract:

In this paper, using butyl titanate （TBOT） and barium titanate （BaTiO₃） as raw materials, BaTiO₃-TiO₂ composite photocatalysts were prepared by hydrothermal method. The effects of different calcination temperatures （400, 500, 600, 700 ℃） on the structure, morphology, and photocatalytic performance of the composite photocatalyst for tetracycline hydrochloride （TCH） were studied. The results show that the increase in calcination temperature promotes the transformation of some TiO₂ into BaTiO₃, the diffraction peak of BaTiO₃ increases, the grain size gradually increases, and the growth and molding of spherical particles become more complete. The band gap width of BaTiO₃-TiO₂ composite photocatalyst is 3.03 eV, and the change in calcination temperature does not change the absorption band edge of BaTiO₃-TiO₂. The absorption intensity of the composite photocatalyst first increases and then decreases with the increase in calcination temperature. The BaTiO₃-TiO₂ composite absorption intensity after annealing at 600 ℃ is the highest. At 180 min, the degradation efficiency of the BaTiO₃-TiO₂ photocatalyst annealed at 600 ℃ for TCH can reach a maximum of 92.80%, which is 24.08% higher than that of the catalyst annealed at 400 ℃. The gradual attenuation of the degradation rate of TCH after five repetitions is less than 7%. The degradation rate of TCH during the fifth repetitions is 70.11%, and the degradation rate of BaTiO₃-TiO₂ is 93.19% at pH=6.2 for 180 min.

Key words: BaTiO₃-TiO₂, photocatalysis, tetracycline hydrochloride, hydrothermal method, calcination temperature