Novel insight into adsorption and co-adsorption of heavy metal ions and an organic pollutant by magnetic graphene nanomaterials in water

•MGO showed the best adsorption capacities for TC, Cd(II) and As(V) among three magnetic graphene nanomaterials.•Adsorption behaviors of MGO in three different types of binary systems were systematically studied.•Mutual effects of TC and Cd(II) in the simultaneously added system were negligible.•Adsorption of As(V) was significantly suppressed in the presence of TC.•Cd(II) and As(V) were co-adsorbed by MGO via electrostatic attraction and formation of type A ternary surface complexation.