The adsorption behavior and mechanistic investigation of Cr(VI) ions removal by poly(2-(dimethylamino)ethyl methacrylate)/poly(ethyleneimine) gels

Abstract

The composite hydrogels based on 2-(dimethylamino)ethyl methacrylate (DMAEMA) and polyethyleneimine (PEI) were prepared by amino radical polymerization and confirmed by Fourier transform infrared (FTIR) spectroscopy and elemental analysis. Then adsorption behavior and mechanism of Cr(VI) ions adsorption on the obtained materials were investigated by scanning electron microscopy, zeta potential determination and thermogravimetric analysis, etc. The adsorption process was found to follow pseudo-second order kinetics and the Langmuir model, and the maximum adsorption capacity of Cr(VI) ions reached 122.8 mg g-1. X-ray photoelectron spectroscopy (XPS) and pH analysis revealed that the Cr(VI) ions were adsorbed into the gels through the electrostatic interaction mechanism, and SO42- in the solution had a great effect on the adsorption process. In addition, a high pH and ionic strength could reduce the uptakes of the adsorbate, which could be used for desorption of Cr(VI) ions from the gels.