New insights on microwave induced rapid degradation of methyl orange based on the joint reaction with acceleration effect between electron hopping and Fe2+-H2O2 reaction of NiFeMnO4 nanocomposites

• Published in: Separation and purification technology 2018-02, Vol.192, p.220-229
• Main Authors: Lei, Yonglin, Lin, Xiaoyan, Liao, Huiwei
• Format: Article
• Language: English
• Subjects: Acceleration effect; Electron–hole excitation; Fe2+-H2O2 reaction; Microwave; NiFeMnO4
• ISSN: 1383-5866; 1873-3794
• DOI: 10.1016/j.seppur.2017.09.067

[Display omitted] •An innovative approach using MW-NiFeMnO4-H2O2 catalytic process was proposed.•Fe2+/Fe3+ in NiFeMnO4 can also contribute to heat semiconducting behavior.•MW absorption and electron hopping of NiFeMnO4 gives it high MW catalytic activity.•More Fe2+ in exterior of NiFeMnO4 lattice makes it high Fenton reaction activity.•The MW-NiFeMnO4-H2O2 process open a new promising avenue for removing pollute. An innovative approach using thermal sensitizer NiFeMnO4 under microwave (MW)-H2O2 condition was proposed to remove organic pollutant of model wastewater. The removal efficiency of 30.0mg/L methyl orange for NiFeMnO4 under MW-H2O2 condition in 6.0min reached up to 96.5%, which is larger than that for activated carbon under same MW-Fenton condition. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET) method, Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) confirmed that the NiFeMnO4 power with an average size of less than 40nm and specific surface areas (19.87m2/g) had a spinel-type cubic structure, in which Ni2+, Mn3+, Mn4+, Fe3+ and Fe2+ occupied the octahedral sites of NiFeMnO4 lattice. The studies of low-temperature thermal degradation, microwave induced oxidation, microwave combining with H2O2 catalytic behavior and effect of active species for NiFeMnO4 indicated that the feasibility to MW-NiFeMnO4-H2O2 route had been successfully verified and joint reaction with acceleration effect of the direct decomposition by MW “hot spots”, the MW “hot spots” accelerated electron–hole excitation and Fe2+-H2O2 reaction was responsible for the degradation of methyl orange in NiFeMnO4-MW-H2O2 system.