The formation and interaction mechanism of magnetic iron oxide/graphene oxide (MGO) nano-composites for efficient removal of methylene blue (MB) and p-tert-butylphenol (PTBP) were investigated by characterization and batch experiments. The structural analysis of MGO showed that iron oxide (Fe3O4 and gamma-Fe2O3) nanoparticles were anchored onto GO nanosheets by Fe-O-C bonds, and tended to distribute on the defects, plicated regions, and edges of GO nanosheets. Based on the adsorption experiments, GO nanosheets in MGO nanocomposites enhanced adsorption capacity for MB and PTBP via pi-pi interaction with recovered sp(2)-hybridized structure. And electrostatic interaction (attraction or repulsion) with oxygen-containing functional group possessed diverse effect for the adsorption of MB and PTBP. Meanwhile, iron oxide nanoparticles in MGO nanocomposites ensured an effective separation without occupying adsorption sites. Results of the regeneration indicated that MGO nanocomposites could retain high removal efficiency after five recycling. Furthermore, the relationship between structure and interaction mechanism were clarified. Our results demonstrate that MGO nanocomposites have a stable structure and favorable adsorption characteristics for MB and PTBP, and can be applied as a promising adsorbent to achieve the efficient removal of aromatic pollutants and separation from aqueous solution. (C) 2017 Elsevier B.V. All rights reserved.