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NiO-NiFe<sub>2</sub>O<sub>4</sub>-rGO Magnetic Nanomaterials for Activated Peroxymonosulfate Degradation of Rhodamine B
- Xu, Xiaochen, Li, Yanfang, Zhang, Guoquan, Yang, Fenglin, He, Ping
- Water 2019 v.11 no.2
- X-ray diffraction, X-ray photoelectron spectroscopy, ambient temperature, catalysts, catalytic activity, ecosystem services, electron paramagnetic resonance spectroscopy, energy-dispersive X-ray analysis, free radicals, magnetism, nanoparticles, nickel, pollutants, rhodamines, scanning electron microscopy, transmission electron microscopes, transmission electron microscopy
- Magnetic spinel ferrites that act as heterogeneous catalysts and generate powerful radicals from peroxymono-sulfate (PMS) for the degradation of organic pollutants have received much attention in recent years due to the characteristic of environmental benefits. In this study, NiO-NiFe<inf>2</inf>O<inf>4</inf>-rGO magnetic nanomaterials were synthesized using a calcinated Ni-Fe-LDH-rGO precursor. The morphology, structure, and chemical constitution were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (EDS), transmission electron microscope (TEM), N<inf>2</inf> adsorption-desorption isotherms, X-ray photoelectron spectroscopy (XPS), and vibrating sample magnetometer (VSM). The catalytic performance of NiO-NiFe<inf>2</inf>O<inf>4</inf>-rGO nanoparticles was thoroughly evaluated for peroxymonosulfate (PMS) activation and its removal of rhodamine B (RhB) from water. The influence of different process parameters on the RhB degradation efficiency was examined. Further, the catalytic stability was evaluated. Under optimized conditions, the NiO-NiFe<inf>2</inf>O<inf>4</inf>-rGO/PMS system was very efficient; RhB fully degraded after 40 min at room temperature. Quenching experiments and electronic paramagnetic resonance (EPR) results suggested that SO<inf>4</inf>−· and OH· were the main active species in the degradation process. Moreover, NiO-NiFe<inf>2</inf>O<inf>4</inf>-rGO catalyst was stable without any apparent activity loss after three cycling runs.