Adsorption and catalytic oxidation of pharmaceuticals by nitrogen-doped reduced graphene oxide/Fe3O4 nanocomposite

A novel nanocomposites (N-RGO/Fe3O4) with the function of adsorption and catalytic degradation of pharmaceuticals in water was successfully synthesized through a facile hydrolysis process. The nitrogen modified reduced graphene oxide (N-RGO) incorporated with magnetic Fe(3)O(4 )nanoparticles could enhance its adsorption and catalytic activity, and allowed the magnetic separability. The as-prepared N-RGO/Fe3O4 exhibited relatively fast adsorption for norfloxacin (NOR) and ketoprofen (KP), and the maximum adsorption capacity on the NRGO/Fe3O4 was 158.1 mg/g for NOR and 468.0 mg/g for KP according to the Langmuir fitting. The N-RGO/Fe3O4 composite could activate persulfate (PS) to generate active radicals. NOR degradation kinetics and pathway by N-RGO/Fe3O4/PS system were also investigated. A complete removal of NOR (20 mg/L) was achieved within 210 min with the addition of 10 mmol/LS2O82- and 100 mg/L N-RGO/Fe3O4, and the removal efficiency of total organic carbon (TOC) was 89%. Electron spin resonance (ESR) tests verified that both center dot OH and SO4-center dot were produced in the catalytic oxidation process, and center dot OH played a significant role in the N-RGO/Fe3O4/PS system.