The Assessment of Cr(VI) Removal by Iron Oxide Nanosheets and Nanowires Synthesized by Thermal Oxidation of Iron in Water Vapour

In this work, iron oxide nanosheets (NSs) and nanowires (NWs) were fabricated by thermal oxidation of iron foils at 500 and 800 °C in the presence of water vapour. Oxidation resulted in multi-scale oxide with the surface oxide comprising of α-Fe2O3 and inner oxide comprising of mostly Fe3O4. The mechanism of formation is discussed to be based on stress-driven mechanism and diffusion paths of iron ions. It was found that the NSs formed could adsorb 112 mg/L aqueous Cr(VI) and the NWs could adsorb 200 mg/L of Cr(VI). It is suggested that the Cr(VI) removal by the iron oxide NSs/NWs due to the electrostatic reaction between the adsorbent and adsorbate.