Preparation and characterization of corn cob activated carbon coated with nano-sized magnetite particles for the removal of Cr(VI)

► Activated carbon coated with magnetite nanoparticles was synthesized from biomass. ► Nano magnetization achieved in a single step process and well characterized. ► Adsorbent showed better superparamagnetism compared to reported elsewhere. ► New nano magnetite adsorbent effectively removed toxic hexavalent chromium. ► Continuous column reactor was designed and the parameters evaluated.