In this study, we found that alumina (Al₂O₃) may facilitate the oxidation of 2,4-dibromophenol (2,4-DBP) by KMnO₄. In KMnO₄/Al₂O₃system, the apparent activation energy was reduced by 13.6 kJ/mol, and the degradation efficiency was improved by 26.5%. The catalytic mechanism was revealed by electrochemical experiments, X-ray photoelectron spectroscopy (XPS) characterization and theoretical calculations that the oxidation potential of MnO₄⁻ was enhanced by 0.03 V. The enhancement was due to the even-more electron deficient state of MnO₄⁻ in presence of Al₂O₃ resulting from the formation of coordination bonds between the O atoms in MnO₄⁻and the empty P orbitals of the Al atoms in Al₂O₃ crystal. The excellent reusability of Al₂O₃, the efficient degradation of 2,4-DBP in real water matrices and the satisfactory performance of fixed-bed reactor collectively suggested that the KMnO₄/Al₂O₃ system has high potential practical application value. This study provides guidance for the development of highly-efficient MnO₄⁻ oxidation treatment systems.

Wenjing Zhang

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