A Ternary Magnetic Recyclable ZnO/Fe 3 O 4 /g-C 3 N 4 Composite Photocatalyst for Efficient Photodegradation of Monoazo Dye

To develop a highly efficient visible light-induced and conveniently recyclable photocatalyst, in this study, a ternary magnetic ZnO/Fe3O4/g-C3N4 composite photocatalyst was synthesized for the photodegradation of Monas dye. The structure and optical performance of the composite photocatalyst were characterized using X-ray diffraction (XRD), transmission electron microscopye (TEM), energy dispersive spectroscopy (EDS), photoluminescence (PL) spectra, ultraviolet–visible diffuse reflection, and photo-electrochemistry. The photocatalytic activities of the prepared ZnO/Fe3O4/g-C3N4 nanocomposites were notably improved, and they were significantly higher than those of pure g-C3N4 and ZnO. Given the presence of the heterojunction between the interfaces of g-C3N4 and ZnO, the higher response to visible light and separation efficiency of the photo-induced electrons and holes enhanced the photocatalytic activities of the ZnO/Fe3O4/g-C3N4 nanocomposites. The stability experiment revealed that ZnO/Fe3O4/g-C3N4-50% demonstrates a relatively higher photocatalytic activity after 5 recycles. The degradation efficiency of MO, AYR, and OG over ZnO/Fe3O4/g-C3N4-50% were 97.87%, 98.05%, and 83.35%, respectively, which was due to the number of dye molecules adsorbed on the photocatalyst and the structure of the azo dye molecule. Azo dyes could be effectively and rapidly photodegraded by the obtained photocatalyst. Therefore, the environment-friendly photocatalyst could be widely applied to the treatment of dye contaminated wastewater.