CuFe₂O₄/TiO₂ magnetic nanocomposites: Sonochemical synthesis and visible-to-NIR light-driven activation of peroxymonosulphate for cephalexin degradation

In this study, magnetic nanocomposites (CuFe₂O₄/TiO₂ MNCs) made-up of CuFe₂O₄ and TiO₂ nanoparticles were prepared through a low-frequency (40 kHz) ultrasound-aided sonochemical approach. The comprehensive analytical characterizations, including XRD, Raman spectroscopy, XPS, TEM and HAADF-STEM micrographs confirmed successful formation of the CuFe₂O₄/TiO₂ MNCs with enhanced crystallinity and uniform distribution of CuFe₂O₄ nanoparticles (∼10 nm) on the TiO₂ surface. The microstructural analysis revealed the exposure of (200) and (211) facets of CuFe₂O₄, while the bandgap energy of the CuFe₂O₄/TiO₂ MNCs was 1.5 eV, indicating their potential towards the solar visible-light-driven photocatalytic applications. Consequently, photocatalytic performance of the CuFe₂O₄/TiO₂ MNCs was evaluated for the degradation of persistent β-lactam antibiotic cephalexin (CPX) under natural solar light irradiation. The CuFe₂O₄/TiO₂ MNCs achieved degradation efficiency of 60 % for CPX within 60 min at first order rate constant of 7.5 × 10⁻⁴ s⁻¹. Meanwhile, introduction of peroxymonosulfate (PMS) significantly enhanced photocatalytic activity by attaining complete degradation of CPX within 20 min at first order rate constant of 25.43 × 10⁻⁴ s⁻¹, due to synergistic generation of SO₄^•– and ^•OH radicals. A threefold enhancement in CPX degradation was observed by the CuFe₂O₄/TiO₂ MNCs + PMS system compared to the system without PMS. The CuFe₂O₄/TiO₂ MNCs + PMS system demonstrated accelerated CPX mineralization. These findings highlight the potential of CuFe₂O₄/TiO₂ MNCs for advanced wastewater treatment applications and provide insights into the efficiency of various solar photocatalytic systems.