NiFe ₂ O ₄ nanostructures as efficient persulfate activation photocatalyst for the removal of metronidazole in water

Abstract The presence of pharmaceuticals in water is one of the major environmental problems facing the world globally. They are often misused, resulting in their widespread presence in the environment and water treatment plants, evading conventional treatment processes. This has necessitated the development of highly effective and efficient wastewater treatment techniques for managing their presence in water. In this study, we report the efficient degradation of metronidazole (MNZ), a widely used antibiotic, by activating persulfate using nickel ferrite (NiFe 2 O 4 ) nanoparticles. NiFe 2 O 4 was prepared through an energy-efficient co-precipitation route and characterized for its structural, optical, and morphological properties using techniques such as x-ray diffraction (XRD), UV–vis spectroscopy, and scanning electron microscopy (SEM). The persulfate activation activity of the obtained catalyst in the presence of visible light was then evaluated against metronidazole. Furthermore, the effect of various process parameters, including pH, persulfate concentration, catalyst dosage, and initial MNZ concentration, was examined. The NiFe 2 O 4 /PS/visible light system exhibited a high MNZ degradation efficiency of 86% within 120 min and a pseudo-first-order kinetics of 0.0143 ± 0.0017. Further evaluation of the radical species produced during the degradation process showed that <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mi mathvariant="normal">SO</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>4</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>⋅</mml:mo> <mml:mo>−</mml:mo> </mml:mrow> </mml:msubsup> </mml:math> and · OH significantly influence MNZ degradation. This study, therefore, presents a promising strategy for environmental purification by highlighting the potential of NiFe 2 O 4 /PS systems as efficient photocatalysts for the remediation of water contaminated with antibiotics.