Magnetic Fe3O4@CuO nanocomposite assembled on graphene oxide sheets for the enhanced removal of arsenic(III/V) from water

•Incorporation with graphene oxide alleviated the aggregation of Fe3O4@CuO nanoparticles.•Synergistic effects of Fe3O4 and CuO facilitated the adsorption-separation performance.•Fe3O4@CuO&GO could be used at least 5 times without leaching of core materials.•Fe3O4@CuO&GO could be used in dynamic reactors for As removal without second pollution.