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

摘要

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(IO@D301)for the removal of Cr(VI)was prepared by the impregnation method.The IO@D301 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,IO@D301 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 pseudofirst-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.