Suqing Wu,Haiyang Hu,Yan Lin,Junliang Zhang,Yun Hang Hu
TiO 2 is widely exploited as a photocatalyst to degrade antibiotic residues in water under UV irradiation, but it is inefficient for visible light photocatalysis due to its large band gap. Herein, it is the first time to report the photodegradation of tetracycline (TC) over TiO 2 under visible light irradiation. 25.1% of removal efficiency for TC was achieved even under 700 nm light irradiation. Furthermore, it was demonstrated that O 2 − species, which were generated from photoexciting of a surface complex between TC molecules and TiO 2 , played a critical role in the visible light photocatalytic degradation of TC. In addition, it was found that the visible light photocatalytic degradation generated different active species and intermediate products from those under UV irradiation. N-doped TiO 2 exhibited even better performance for visible-light photocatalytic degradation of TC with higher removal efficiency and larger mineralization rate, which followed different degradation-mechanism.
In this work, beta zeolite supported Ti 3+ -TiO 2 /CdS heterojunction was prepared for photodegradation of tetracycline under visible-light irradiation, and zeolite served as a support for the high dispersions of the Ti 3+ -TiO 2 nanoparticles . The obtained zeolite/Ti 3+ -TiO 2 /CdS heterojunction showed a relatively high surface areas of approximately 63.2 m 2 g −1 , much higher than those of the prepared Ti 3+ -TiO 2 /CdS (27.1 m 2 g −1 ), Ti 3+ -TiO 2 (36.5 m 2 g −1 ), and CdS (31.1 m 2 g −1 ), strongly demonstrating the significant of zeolite for high dispersion of the Ti 3+ -TiO 2 /CdS composite. Besides, the experimental results also showed that the photocatalytic degradation efficiency could reach 78 % in 3 min for the zeolite/Ti 3+ -TiO 2 /CdS heterojunction, and the corresponding rate constant was as high as 0.788 min −1 , which was 26.90 times that of pristine Ti 3+ -TiO 2 , 2.24 times of pristine CdS , and 2.04 times of the Ti 3+ -TiO 2 /CdS composite, mainly because of the supporting effects of zeolite and the formation of Ti 3+ -TiO 2 /CdS heterostructure for highly enhanced charge separation. In addition, the trapping experiment revealed that the main reactive species involved in tetracycline degradation were attributed to the photo-generated holes and ⸱O 2 - species.
危险品化学品经营许可证（带存储）