Efficient adsorption to hexavalent chromium by iron oxalate modified D301: Characterization, performance and mechanisms

Abstract

Chromium is a common harmful pollutant with high toxicity and low bearing capacity of soil and water. Excellent salinity resistance, a wide pH range, and high regeneration capacity were essential for qualified adsorbents used in removing hexavalent chromium (Cr(VI)) from polluted water. Herein, iron oxalate modified weak basic resin ([email protected]) for the removal of Cr(VI) was prepared by the impregnation method. The [email protected] was characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), X-Ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Owing to abundant amine, carboxyl groups and iron ions existing on the surface, [email protected] possesses high adsorption and salinity resistance capacity for Cr(VI). The maximum adsorption capacity of IO301 towards Cr(VI) reached 201.30 mg·g−1 at 293 K and a pH of 5. The adsorption equilibrium was well fitted by the Freundlich model, and the adsorption process was described by the pseudo-first-order kinetics model as spontaneous and exothermic. The mechanism may be identified as electrostatic attraction, coordination, and reduction, which was confirmed by FT-IR and X-ray photoelectron spectroscopy.