Efficient degradation of metronidazole in wastewater by FeO_x/GAC catalytic ozonation

To remove the metronidazole, the iron oxides loaded on granular activated carbon (FeO_x-GAC) were prepared by the impregnation–calcination approach. The physicochemical properties of the catalysts were characterized by electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The results show that FeO_x-GAC has a porous structure, in which the iron oxides with a variety of valence states are smoothly attached on the activated carbon. The catalytic activity of FeO_x-GAC was evaluated for metronidazole removal, exhibiting great catalytic efficiency of the catalyst. Besides, the catalytic ozonation of metronidazole was optimized by varying the dose of ozone and catalyst, as well as the pH of the solution.