Preparation of ZnFe2O4@ZnWO4 composites from MOF-based materials as effective and magnetically separable photocatalysts for degradation of tetracycline antibiotics

An efficient ZnFe 2 O 4 /ZnWO 4 photocatalyst based on Cu-MOF was prepared for the photo-Fenton-degradation of tetracycline under visible light. The microstructure as well as photoelectrochemical properties were qualitatively and quantitatively analyzed using XRD, SEM, TEM, XPS, PL, EIS and other characterization means, and the photodegradation mechanism was explored. The results showed that the rod-shaped ZnWO 4 was combined with spherical ZnFe 2 O 4 encapsulated on MOF, and the catalyst exhibited excellent light absorption, bulk phase separation and interfacial separation of photogenerated charges, resulting in excellent photo-Fenton-removal performance of tetracycline (TC). Among them, the ZnFe 2 O 4 /30 %ZnWO 4 /10 %Cu-MOF photo-Fenton degradation was the best, with more than 99 % degradation of TC within 60 min under simulated visible light. In addition, ZFO@ZWO@MOF has good photostability and reusability, and can be used to photo-Fenton degrade TC by a convenient magnetic recycling method. The radical capture experiments and electron spin resonance experiments fully proved that the main active substances for degrading TC are ·O 2 - and ·OH. This study provides an opportunity to construct type II heterojunction photocatalysts with high efficiency and convenient recycling, and offers new perspectives and insights into the purification mechanism of pollutants.