Mg–Fe–Al–O spinel: Preparation and application as a heterogeneous photo-Fenton catalyst for degrading Rhodamine B

• Published in: Chemosphere (Oxford) Vol. 304; p. 135318
• Main Authors: Zhang, Jiayu, Yan, Mingwei, Sun, Guangchao, Li, Xiang, Hao, Bianlei, Liu, Kaiqi
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-10-2022
• Subjects: DFT; Mg-Fe-Al-O spinels; Photo-Fenton reaction; Reaction sintering; Rhodamine B; Reaction sintering; DFT; Rhodamine B; Photo-Fenton reaction; Mg-Fe-Al-O spinels
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2022.135318

It is an urgent need to develop new environmentally friendly spinel ferrites with high catalytic efficiency. In this work, a series of Mg–Fe–Al–O spinels with different ratios of Mg/Al were successfully synthesized by the reaction sintering method and were used as a heterogeneous photo-Fenton catalyst for degradation of Rhodamine B (RhB). The effect of different ratios of Mg/Al on the properties of Mg–Fe–Al–O spinel was characterized and analyzed through a range of advanced characterization techniques and DFT calculations. The influence factors on the photo-Fenton reaction catalyzed by Mg–Fe–Al–O spinels were systematically investigated. The results showed that the prepared Mg–Fe–Al–O spinels had larger lattice parameters, wider bandgap, and stronger magnetism, with the Mg content increased. Among them, Mg-9 (Mg0.88Fe1.88Al0.23O4) had the best catalytic performance in the photo-Fenton reaction. The degradation efficiency of RhB reached 98.45%, and the TOC removal efficiency was 83.47%. The elemental valence and PDOS of Mg-9 (Mg0.88Fe1.88Al0.23O4) spinels were closer to MgFe2O4. The photo-generated holes could directly oxidize water and hydroxyl to generate reactive oxygen species ·OH, improving the catalytic activity.
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•Mg–Fe–Al–O spinels synthesized by reaction sintering were first utilized as a photo-Fenton catalyst.•The effect of Mg/Al was systematically explored.•The increment of Mg content could result in the Fermi level closer to the valence band maximum.•The Mg–Fe–Al–O spinels had easy recyclability and favorable stability.