Magnetite/graphite carbon nitride composite for peroxymonosulfate non-radical activation

Magnetite-based catalysts are cost-effective and recyclable in water treatment processes. In this work, we constructed Fe3O4/g-C3N4 (FeOCN) catalyst by compounding g-C3N4 and Fe3O4. Based on characterization and experiments, the local positive and negative charges create active sites for catalyzing peroxymonosulfate (PMS) and bisphenol A (BPA) was confirmed. Through free radical quenching experiment, electron spin resonance spectroscopy, oxidant consumption and XPS, the mechanism of FeOCN-catalyzed PMS degradation of BPA was discussed. The electron transfer of surface-bound reactive complexes and O-1(2) were proved to play a role in the system. FeOCN not only achieves a pseudo first-order rate constant 35.7 times higher than Fe3O4, but also imparts pH stability (3-11) and applicability in actual water substrates (tap water, lake water, groundwater). This work provides a new insight into the engineering design of magnetite in the water treatment process to effectively treat organically polluted water.