Superior degradation of organic pollutants and H2O2 generation ability on environmentally-sound constructed Fe3O4-Cu nanocomposite

Abstract

The present work aimed to account for the first time green, and eco-friendly synthesis of Fe3O4/Cu nanocomposite as magneto-recyclable photocatalyst using Rosmarinus officinalis leaves aqueous extract. R. officinalis leaves extract played three significant roles in improving physicochemical properties of Fe3O4 nanoparticles as reducing, stabilizing and capping agents and can convert Cu2+ ions into Cu0. Several characterization techniques were employed to investigate the crystal structure, surface chemistry, morphology, and optical properties of the produced nanomaterials. The UV–Vis DRS spectra exhibited a low band-gap (1.7 eV), appropriate for an effective visible-light degradation. Effectiveness of Fe3O4 nanoparticles and Fe3O4/Cu nanocomposite as photocatalysts were examined under visible light illumination on an aqueous contaminant solution. Degradation efficiencies of methyl orange, imipenem, and imatinib mesylate, three types of organic contaminations were about 50–96% after 5400 s irradiation over Fe3O4 nanoparticles and Fe3O4/Cu nanocomposite. Total organic carbon analysis results confirmed degradation efficiencies of all samples. Trapping experiments results verified that O2− was the main oxidative species in the degradation of organic contaminations. The as-prepared photocatalysts could be reused after five successive cycles with no significant reduction in degradation efficiency. Besides, biogenic nanoparticles and nanocomposite were promoted H2O2 production. The photochemical production of H2O2 was achieved under visible light irradiation toward the two-electron oxygen reduction reaction. The plausible mechanisms for photocatalytic and degradations were proposed, which suggested the prepared photocatalysts' remarkable potential for removing contaminants with complex structures.