Photocatalytic degradation of tetracycline hydrochloride by lanthanum doped TiO@g-CN activated persulfate under visible light irradiation.

In this work, a visible light-driven La/TiO@g-CN photocatalyst was synthesized for the photodegradation of tetracycline hydrochloride (TCH) in the presence of peroxydisulfate (PDS) in an internal loop-lift reactor. The surface morphology and structure of La/TiO@g-CN have been characterized by XRD, SEM-EDS, FTIR, XPS, and UV/vis DRS. La/TiO@g-CN displays outstanding photocatalytic performance and reusability. After four reuse cycles of the vis/La/TiO@g-CN/PDS system, the TCH degradation rate and efficiency still reached 0.083 min and 97.68%, respectively. Reactive species in this system included free radicals SO˙, ˙OH, and ˙O , as well as non-radicals e, and h, as established from the results of chemical quenching experiments. Moreover, a mechanism of action of the vis/La/TiO@g-CN/PDS system for TCH degradation was proposed. The acute toxicity of the reaction solution towards T3 spp. in the vis/La/TiO@g-CN/PDS process increased during the first 60 min and then decreased, illustrating that vis/La/TiO@g-CN/PDS provided an effective and safe method for the removal of TCH.