Walnut Shell Loaded with Cobalt Ferrite as Efficient Peroxymonosulfate Activator to Degrade Ofloxacin

In this study, the walnut shell (WS) supported CoFe 2 O 4 nanopowder material (CoFe 2 O 4 /WS) were synthesized and characterized by X-ray diffraction, scanning electron microscopy, fourier transform infrared spectrometer, transmission electron microscope and X-ray photoelectron spectroscopy. The CoFe 2 O 4 /WS exhibited excellent catalytic activity in the process of activating peroxymonosulfate (PMS) to degrade ofloxacin (OFL). The results showed that 92.8% of OFL removal efficiency and 76.1% of mineralization rate were achieved at 1 g L –1 CoFe 2 O 4 /WS, 1 g L –1 PMS within 30 min. Moreover, the results of coexisting anions and organic matter indicated that the CoFe 2 O 4 /WS/PMS system has a certain anti-interference ability in complex environment. Furthermore, radical identification experiment demonstrated that SO 4 ·− was the dominant active substance during the OFL degradation process, and a possible activation mechanism of PMS by CoFe 2 O 4 /WS was proposed. Finally, possible degradation pathways of OFL were inferred based on the reaction intermediates detected by high-performance liquid chromatography-mass spectrometry. These findings will enrich the understanding of sulfate radical-advanced oxidation process (SR-AOPs) for antibiotic wastewater treatment and will guide the development of metal-organic frameworks as catalysts for PMS.