Ingenious construction of a magnetic-recyclable photo-Fenton catalyst ZnFeO@MIL-88A(Fe) and its adsorption-degradation activity toward levofloxacin.

Monotonic pore size and particles inseparability of metal-organic frameworks (MOFs) caused serious effects on its light absorption ability and charge separation, restricting its application for antibiotic such as levofloxacin (LEV) degradation in water. In this study, a magnetically detachable nano-photocatalyst (ZnFeO@MIL-88A(Fe)) was synthesized using a simple two-step hydrothermal technique. The morphology and microstructure analyses showed that n-type ZnFeO catalyst particles were efficiently assembled onto the surface of MIL-88A(Fe) crystal. Photocatalytic activity studies indicated that the ZnFeO@MIL-88A(Fe) plus HO exhibiting a significantly boosted photo-Fenton activity toward LEV at visible light irradiation, compared to the pure ZnFeO and MIL-88A(Fe), the degradation efficiency accordingly reached up to nearly 82% and 25% within 60 min. This excellent photocatalytic performance was ascribed to the synergistic effects of the heterogeneous structure of ZnFeO and MIL-88A(Fe), whereby the efficient separation of charge carriers in the catalytic system is mutually reinforced with the efficient reduction of Fe and Fe. Meanwhile, the degradation mechanism and intermediates of LEV during the photo-Fenton reaction process were also studied in depth through free radical burst, electron paramagnetic resonance, and mass spectrometry analyses, etc. Additionally, the ZnFeO@MIL-88A(Fe) composite catalyst displayed significant stability and ease of separation, indicating potential for the photo-oxidative degradation of organic pollutants.