Highly-efficient and stable MgCo2O4 spinel for bisphenol a removal by activating peroxymonosulfate via radical and non-radical pathways

Abstract Nowadays, the limited catalytic efficiency, secondary pollution of metal leaching and stability decrease during reuse bring challenges to practical application of heterogeneous catalysts in sulfate radical-based advanced oxidation processes. Herein, MgCo2O4 spinel was synthesized through hydrothermal method and tested for its catalytic performance of activating PMS by using bisphenol A (BPA) as the target pollutant. MgCo2O4/PMS system can degrade 99.6% BPA efficiently at pH 7.2 within 10 min. The morphological and physicochemical properties of MgCo2O4 were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). Unlike conventional PMS activation, radical and non-radical pathways were identified through utilizing X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR), and radical quenching experiments. Tetrahedral Mg2+ might make MgCo2O4 more stable and promote the Co2+/Co3+ redox, which dominated the catalytic ability of MgCo2O4. MgCo2O4 spinel is efficient, stable, low-cost, and simple to synthesize, leading to BPA degradation via both radical and non-radical pathways. This research would extend the mechanism and potential application of spinel catalysis in water treatment.