Efficient degradation of organophosphorus herbicide by free‐standing 3D reduced graphene oxide supported nFe3O4 catalytic‐activated persulfate

Abstract

AbstractBACKGROUNDOrganophosphorus herbicides in water are an increasingly critical environmental problem. Given this challenge, a free‐standing 3D reduced graphene oxide (GO) foam supporting Fe3O4 nanoparticles (3D‐rGO‐Fe3O4) was synthesized using GO as a precursor and applied as an efficient persulfate activator for glyphosate (GLY) degradation.RESULTSThe effects of Fe3O4 mass, pH, oxidant dosage, temperature and common ions on GLY degradation were investigated in detail. Analytical techniques using scanning electron microscopy (SEM), Fourier transform infrared analysis (FTIR) and X‐ray photoelectron spectroscopy (XPS) indicated that the 3D foam prevented aggregation of the Fe3O4 nanoparticles by in situ uniform formation on GO nanosheets. The addition of Fe was vitally important for activation of the oxidation system. The results of batch‐scale experiments illustrated that the GLY degradation efficiency reached 96.8% with initial GLY concentration 30 mg L−1, graphene:Fe3O4 mass ratio 1:7, solution pH 4 and persulfate mass 48 mg. High temperatures could significantly facilitate GLY degradation. Additionally, the 3D‐rGO‐Fe3O4 material proved highly stable according to the replicated test results. Furthermore, EPR test results revealed that Na2S2O8 catalytic activation by 3D‐rGO‐Fe3O4 mainly produced ·OH and SO4−·, and the predominant free radical was SO4−· in the current experiment.CONCLUSIONThe results indicate that 3D‐rGO‐Fe3O4 has good catalytic activity and stability, and, accordingly, has high application prospects for the remediation of organophosphorus herbicide‐contaminated water. © 2023 Society of Chemical Industry (SCI).