Periodate activation with stable MgMn2O4 spinel for bisphenol A removal: Radical and non-radical pathways

Abstract

Nowadays, the limited catalytic efficiency, metal leaching, and stability decrease during catalyst reuse hinder the heterogeneous catalysis application in water treatment. Moreover, the heterogeneous catalysis mechanism regarding novel sodium periodate (NaIO4)-based advanced oxidation process (AOP) is ambiguous. Herein, MgMn2O4 spinel was synthesized through the co-precipitation method to test the NaIO4-based AOP’s mechanism. The morphological and physicochemical properties of MgMn2O4 were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). In this research, 0.1 g L−1 MgMn2O4 activated 1 mM NaIO4 to remove 10 μM bisphenol A (BPA) in 60 min without toxic iodine species generation and the acute toxicity decrease through radical (iodine active substances, IO3•) and non-radical (1O2, Manganese (IV)-oxo species) pathways by utilizing X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR), radical quenching experiments, and methyl phenyl sulfoxide (PMSO)-based probing experiment. With tetrahedral Mg2+ introduction and the Mn2+ /Mn3+ /Mn4+ redox domination, the MgMn2O4 shows high catalytic ability for NaIO4. To summarize, this research would extend the mechanism for the NaIO4-based advanced oxidation process.