Facile Preparation of Magnetically Separable Fe 3 O 4 /ZnO Nanocomposite with Enhanced Photocatalytic Activity for Degradation of Rhodamine B.

Magnetic separation of photocatalysts holds great promise for water treatment. A magnetic separation method has a positive effect on the recovery of catalysts after degradation. In this paper, an efficient and reusable catalytic system is developed based on coating magnetic Fe ₃ O ₄ by depositing Fe ²⁺ on the surface of ZnO. The Fe ₃ O ₄ /ZnO nanocomposite exhibits enhanced performance for organic pollutant degradation. The Fe ₃ O ₄ /ZnO system demonstrates a high photocatalytic activity of 100% degradation efficiency in Rhodamine B (RhB) degradation under UV light irradiation for 50 min. The excellent photocatalytic activity is primarily due to the separation of photogenerated electron-hole pairs being facilitated by the strong interaction between Fe ₃ O ₄ and ZnO. The induction of the magnetic Fe ₃ O ₄ endows the Fe ₃ O ₄ /ZnO composite with superior magnetic separation capability from water. Experiments with different radical scavengers revealed that the hydroxyl radical (·OH) is the key reactive radical for the effective degradation of RhB. This work innovatively affords a common interfacial dopant deposition strategy for catalytic application in the degradation of organic dye pollutants and catalyst separation from wastewater efficiently.