Spherical polystyrene-supported nano-Fe3O4 of high capacity and low-field separation for arsenate removal from water

► Nano-Fe3O4 was coated onto polystyrene (PS) beads to obtain PS-Fe3O4 for arsenate removal from water. ► PS-Fe3O4 exhibited higher capacity and faster kinetics for arsenate adsorption than Fe3O4. ► PS-Fe3O4 can be effectively separated from water under a low magnetic field (<0.035 T). ► PS-Fe3O4 can be employed for multiple uses after regeneration with alkaline solution.