Heterogeneous Fenton-like discoloration of methyl orange using Fe3O4/MWCNTs as catalyst: combination mechanism and affecting parameters

Multi-walled carbon nanotubes (MWCNTs) can act not only as a support for Fe₃O₄ nanoparticles (NPs) but also as a coworker with synergistic effect, accordingly improving the heterogeneous Fenton-like efficiency of Fe₃O₄ NPs. In this study, Fe₃O₄ NPs were in situ anchored onto MWCNTs by a moderate co-precipitation method and the as-prepared Fe₃O₄/MWCNTs nanocomposites were employed as the highly efficient Fenton-like catalysts. The analyses of XRD, FTIR, Raman, FESEM, TEM and HRTEM results indicated the formation of Fe₃O₄ crystals in Fe₃O₄/MWCNTs nanocomposites prepared at different conditions and the interaction between Fe₃O₄ NPs and MWCNTs. Over a wide pH range, the surface of modified MWCNTs possessed negative charges. Based on these results, the possible combination mechanism between Fe₃O₄ NPs and MWCNTs was discussed and proposed. Moreover, the effects of preparation and catalytic conditions on the Fenton-like catalytic efficiency were investigated in order to gain further insight into the heterogeneous Fenton-like reaction catalyzed by Fe₃O₄/MWCNTs nanocomposites.