Catalytic activity of a magnetic Fe2O3@CoFe2O4 nanocomposite in peroxymonosulfate activation for norfloxacin removal

Abstract

In this study, Fe₂O₃ nanoparticles derived from a metal organic framework (MIL-88B) template were successfully decorated on CoFe₂O₄ flower-like nanostructures through a facile hydrothermal/calcination method. The magnetic nanocomposite (Fe₂O₃@CoFe₂O₄) exhibited high catalytic activity in norfloxacin (NOR) removal via peroxymonosulfate (PMS) activation. The catalyst was characterized by using different techniques including FT-IR, XRD, FE-SEM, EDS, TEM, BET, VSM, and ICP-AES analysis. The as-made nanocomposite showed high efficiency in NOR degradation by PMS, and the first-order rate constant (k_app) of the reaction was found to be 0.1883 ± 0.0214 min⁻¹ over Fe₂O₃@CoFe₂O₄ activated by PMS. The effects of operational parameters such as pH, reaction temperature, catalyst amount and PMS dosage, and the influence of water matrix species were investigated in this reaction. Under natural conditions (pH = 7), the best catalytic activity was observed, while acidic/basic conditions were not desirable for this reaction. Also, catalyst concentration exhibited a greater effect on NOR degradation than PMS dose. Based on scavenger experiments (i.e. tert-butyl alcohol and methanol), the generation of sulfate (SO₄˙⁻) and hydroxyl (HO˙) radicals over the Fe₂O₃@CoFe₂O₄/PMS system plays a vital role in NOR removal. Also, the Fe₂O₃@CoFe₂O₄ nanocomposite was able to activate PMS for NOR degradation for successive catalytic runs without losing activity. The developed catalyst demonstrated excellent potential for the degradation of pollutants in wastewater.