Microwave-assisted Synthesis of Fe2O3/Mn2O3/rGO Nanocomposite for Effective Remediation of Parathion Pesticide under Visible Light Illumination

Abstract

Organophosphorus compounds are effective pesticides and insecticides but are also persistent and highly hazardous. In this work, a Fe₂O₃/Mn₂O₃/reduced-graphene-oxide (FM/rGO) composite was utilized as a photocatalyst for the degradation of parathion, a typical organophosphorus pesticide. The cost-effective and environmentally friendly FM/rGO material was prepared by a coprecipitation method assisted by microwave irradiation and characterized by various techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and UV‒Vis spectroscopy. Compared with pristine Fe₂O₃ and Mn₂O₃, the immobilization of Fe₂O₃ and Mn₂O₃ on the rGO support significantly enhanced the photodegradation of parathion, primarily by reducing the recombination rate of the photogenerated electron‒hole pairs. The FM/rGO achieved approximately 100% degradation of parathion within 45 min and mineralized nearly 90% of the initial parathion after 150 min under visible light irradiation. In addition, FM/rGO exhibited outstanding durability and recyclability, with only a 5% reduction in degradation efficiency after seven consecutive cycles.