Adsorption and catalytic oxidation of pharmaceuticals by nitrogen-doped reduced graphene oxide/Fe 3 O 4 nanocomposite

•N-RGO/Fe3O4 is prepared by N modified reduced graphene oxide with Fe3O4.•N-RGO/Fe3O4 nanocomposite has high adsorption capacity for pharmaceuticals.•Maximum adsorption capacity of N-RGO/Fe3O4 for norfloxacin is 158.1 mg/g.•N-RGO/Fe3O4 exhibits the catalytic oxidation of the adsorbed pharmaceuticals.•N-RGO/Fe3O4 can activate persulfate to generate both OH and SO4−.