Activation of peroxymonosulphate using a highly efficient and stable ZnFe₂O₄ catalyst for tetracycline degradation

Tetracycline (TC) is a widely used antibiotic that adversely affects ecosystems and, therefore, must be removed from the environment. Owing to their strong ability to oxidise pollutants, including antibiotics, and selectivity for these pollutants, an improved oxidation method based on sulphate radicals (SO4·^-) has gained considerable interest. In this study, a novel technique for removing TC was developed by activating peroxymonosulphate (PMS) using a ZnFe₂O₄ catalyst. Using the co-precipitation method, a ZnFe₂O₄ catalyst was prepared by doping zinc into iron-based materials, which increased the redox cycle, while PMS was active and facilitated the production of free radicals. According to electron paramagnetic resonance spectroscopy results, a ZnFe₂O₄ catalyst may activate PMS and generate SO₄·^-, HO·, O₂·^-, and ¹O₂ to eliminate TC. This research offers a new method for creating highly effective heterogeneous catalysts that can activate PMS and destroy antibiotics. The study proposes the following degradation pathways: hydroxylation and ring-opening of TC based on the products identified using ultra-performance liquid chromatography-mass spectrometry. These results illustrated that the prepared ZnFe₂O₄ catalyst effectively removed TC and exhibited excellent catalytic performance.