▎ 摘　　要

In this study, Fe3O4/gallic acid/graphene oxide magnetic nanocomposites (Fe3O4/GA/GO MNPs) were synthesized as heterogeneous Fenton catalysts to activate H2O2 to degrade methylene blue (MB). The catalysts were characterized by X-ray diffraction (XRD), zeta potential analysis, thermogravimetric analysis (TGA), transmission electron microscopy (TEM) and X-ray Photoelectron Spectroscopy (XPS). The addition of GA resulted in crystal defects on the surface of Fe3O4/GA/GO which improved its catalytic properties. Moreover, Fe3O4/GA/GO had larger surface area, correspondingly exposing more active sites for H2O2 activation, as well as enhancing the adsorption of MB which also promoted its catalytic properties. Complete removal of MB (0.2 mM) and remarkable mineralization of total organic carbon (TOC) (66.7%) were obtained within 420 min at pH 6.0 and 30 degrees C by using 1.0 g L (1) Fe3O4/GA/GO MNPs and 160.0 mM H2O2. Furthermore, MB could be completely degraded by Fe3O4/GA/GO MNPs in a wide pH value ranging from 3.0 to 10.0. The catalyst showed stable catalytic activity, as well as good mechanical stability, and could be recycled 10 times.