Photocatalytic activation of persulfate by a TiO2/ZnFe2O4 Z heterojunction photocatalyst for efficient degradation of tetracycline hydrochloride

Abstract

The treatment of antibiotic wastewater is one of the urgent environmental problems, and photocatalysis technology has become an ideal choice for the treatment of antibiotic wastewater by virtue of its high efficiency, clean and environmentally friendly. In this work, TiO2/ZnFe2O4 Z heterojunction was successfully prepared by hydrothermal synthesis method, and tetracycline hydrochloride (TCH) wastewater was efficiently degraded in the presence of persulfate (PDS). The effects of the catalyst dosage, the amount of PDS, pH and nine common cations and anions on the photocatalytic system were also investigated. In the photocatalytic synergic persulfate system, TiO2/ZnFe2O4 photocatalyst, under simulated sunlight irradiation for 18min, the TCH removal rate is as high as 97%, and the effect of pH is very small, and can achieve efficient removal in the range of pH=4~10. Through the free radical trapping experiment, the photogenerated carrier migration path was inferred and the degradation mechanism of the photocatalytic system was analyzed. It can be seen that the free radicals (SO4-•, •OH and O2•-) and non-free radicals (h+ and 1O2) in the system can degrade TCH together. In addition, TiO2/ZnFe2O4 photocatalyst has excellent cyclic stability. This study provides reference value for the design and optimization of photocatalysis-persulfate advanced oxidation system, and further promotes the wide application of this system in environmental governance.