UV-assisted nitrogen-doped reduced graphene oxide/Fe3O4 composite activated peroxodisulfate degradation of norfloxacin

Abstract

We reported the preparation of NGO-Fe₃O₄ by simple hydrothermal-co-precipitation. The catalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). It was demonstrated that norfloxacin (NOR) could be effectively degraded by the UV/NGO-Fe₃O₄/PDS system. The degradation efficiency reached 100% within 13 min (the concentration of NOR and $S_2{O}_8^{2-}$ were 100 mg L^-1 and 1 mM, respectively; m(NGO-Fe₃O₄): m(PDS) = 4: 1; pH: 3.0). In addition, NGO-Fe₃O₄ showed stable catalytic activity in recycling. The analysis found that the in-situ generated ·OH was the main active free radicals but ${\mathrm{SO}}_4^{-}\cdot$ also participated in the NOR degradation. Based on the identified intermediates, the NOR degradation pathways were proposed with UV/NGO-Fe₃O₄/PDS system.

Keywords: NGO-Fe3O4; UV; norfloxacin. degradation kinetics; peroxodisulfate.