Catalytic reduction of p-nitrophenol by g-C3N4/CuFe2O4 magnetic nanocomposites

Abstract

Phenolic pollutants in industrial organic wastewater are not only highly toxic but also difficult to degrade. Therefore, the treatment of phenol-containing organic wastewater has been a problem for countries around the world. In this study, g-C₃N₄/CuFe₂O₄ (CNCF) composite catalysts with magnetic properties and easy to be recycled were prepared by doping copper ferrite (CuFe₂O₄) with different masses of carbon nitride (g-C₃N₄) using hydrothermal method. NaBH₄ was injected to catalyze the reduction of the target pollutant p-nitrophenol (p-NP) to determine the optimal doping ratio of the composite. The surface morphology, structural properties and elemental types of the catalysts were analyzed using scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray diffractograms (XRD), Fourier infrared (FT-IR), X-ray photoelectron spectroscopy (XPS), vibrating sample magnetometer (VSM) and other characterization tools. It is shown that the pores between g-C₃N₄ sheets are uniformly filled by CuFe₂O₄ nanoparticles, and CuFe₂O₄ nanoparticles are successfully loaded on g-C₃N₄ nanosheets, which are doped and composited together to form a 3D heterostructure, which effectively facilitates the transfer of electrons and thus improves the catalytic activity. When 0.05 g of CNCF composite catalyst was added, the adsorption of p-NP and BH₄⁻ helped to overcome the kinetic hindrance of the reaction, resulting in a complete degradation of p-NP in 6 min of reaction when the molar ratio of NaBH₄ to p-NP was only 100:1. The CNCF can be reclaimed and repurposed using magnets, and it also demonstrates excellent catalytic performance after six cycles. The changes in bioacute toxicity of p-NP before and after degradation were evaluated, and it was concluded that its photoinhibition rate decreased from 88.72 % to 17.54 %, which is a significant reduction in biotoxicity.