Superparamagnetic high-surface-area Fe3O4 nanoparticles as adsorbents for arsenic removal

► Fe3O4 nanoparticles with a high specific surface area were synthesized. ► Fe3O4 nanoparticles have a high specific surface area of about 180 m2/g. ► Fe3O4 nanoparticles exhibit high water solubility. ► Fe3O4 nanoparticles exhibit good adsorption behavior for removing arsenic ions.