Heterogeneous activation of peroxymonosulfate by a novel magnetic 3D γ-MnO2@ZnFe2O4/rGO nanohybrid as a robust catalyst for phenol degradation

Three-dimensional (3D) gamma-MnO2@ZnFe2O4/reduced graphene oxide (rGO) nanohybrids were synthesized using a one -pot hydrothermal self -assembly method. The morphology and properties of the nanohybrids were investigated. The synergistic interactions among gamma-MnO2, ZnFe2O4, and rGO resulted in 3D nanoflakes distributed uniformly in the rGO structure with a thickness of approximately 2-5 nm, leading to a high surface area. The nanohybrid containing 10 wt. % rGO exhibited superior catalytic activities for phenol degradation through the activation of peroxymonosulfate (PMS) to generate active sulfate radicals (SO4 center dot-). Typically, 50 mL of a 20 ppm phenol solution was degraded completely and 85% of the carbon content had been mineralized in 30 min at 25 degrees C using 10 mg of the nanohybrid. The nanohybrid could be recovered easily using a magnet and reused, maintaining high stability during catalytic oxidation. The 3D gamma-MnO2@ZnFe2O4/rGO nanohybrid catalyst could be applied to the removal of hard-to-degrade waste materials owing to its high efficiency and excellent reusability.