Rapid and efficient removal of naproxen from water by CuFe₂O₄ with peroxymonosulfate

Naproxen, a widely used nonsteroidal anti-inflammatory drug, has been detected in many environmental matrixes and is regarded as an emerging pollutant. Sulfate radical (SO₄·^-) -based advanced oxidation processes have attracted wide attention due to their high efficiency and applicability in the removal of emerging contaminants. In this study, CuFe₂O₄ was used as an efficient catalyst to activate peroxymonosulfate to oxidize naproxen. The results suggested that 92.3% of naproxen was degraded and 50.3% total organic carbon was removed in 60 min in the presence of 0.3 g·L^-1 CuFe₂O₄ and 2 mM peroxymonosulfate. This degradation system showed strong adaptability in a wide pH range from 4.0 to 10.0. Free radical scavenger experiments and electron spin resonance analysis indicated that ¹O₂, ·OH, and SO₄·^- are the main active species. Finally, the potential degradation pathways of naproxen were proposed by detecting and analyzing the degradation products with ultra-high-performance liquid chromatography combined with mass spectrometry. The results of this study suggest that the CuFe₂O₄-activated peroxymonosulfate system is a promising technology for the removal of naproxen from natural water.