Synthesis, characterization and investigation of photocatalytic activity of ZnFe2O4@MnO–GO and ZnFe2O4@MnO–rGO nanocomposites for degradation of dye Congo red from wastewater under visible light irradiation

Abstract

Magnetic ZnFe2O4@MnO–graphene oxide and ZnFe2O4@MnO–reduced graphene oxide nanocomposites were prepared via a facile co-precipitation and hydrothermal methods and characterized by X-ray powder diffraction, diffuse reflectance UV–Vis spectroscopy, photoluminescence (PL) spectra, Transmission electron microscopy, field emission scanning electron microscopy, Fourier transform infrared spectroscopy, vibrating sample magnetometry techniques and Bruner–Emmett–Teller (BET). The ZnFe2O4@MnO, ZnFe2O4@MnO–GO and ZnFe2O4@MnO–rGO nanoparticles were found to have a size of 20–40 nm and were spread out on the graphene oxide nanosheets and reduced graphene oxide nanosheets. Magnetic studies demonstrated that the ZnFe2O4@MnO–graphene oxide and ZnFe2O4@MnO–reduced graphene oxide nanocomposites can be easily separated from the solution by an external magnetic field. The photocatalytic degradation of Congo red dye (CR) was evaluated based on the removal of CR in aqueous solution in 35 min of visible light irradiation. The photocatalytic activity was affected by the structural and optical properties as well as the surface area of the samples. Compared with pure ZnFe2O4@MnO and ZnFe2O4@MnO–reduced graphene oxide nanocomposite, the ZnFe2O4@MnO–graphene oxide nanocomposite displayed a high photocatalytic activity on the photodegradation of Congo red. The prepared ZnFe2O4@MnO–graphene oxide nanocomposite can be potentially applied as a visible light responsive catalyst and magnetically separable photocatalyst and thus as a powerful separation tool for solving water pollution problems.