Adsorption and desorption of phenanthrene by magnetic graphene nanomaterials from water: Roles of pH, heavy metal ions and natural organic matter

•Magnetic chemically-reduced graphene had the highest adsorption capacity for phenanthrene.•Phenanthrene was adsorbed onto magnetic chemically-reduced graphene mainly via π–π interaction.•Humic acids suppressed phenanthrene adsorption and desorption processes.•Deformation and rearrangement of graphene nanosheets contributed to desorption hysteresis.