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

摘要

The composite hydrogels based on N,N’-dimethylamino ethyl methacrylate (DMAEMA) and polyethyleneimine (PEI) were prepared by amino radical polymerization and confirmed by Fourier Transform Infrared Spectra (FTIR) and elemental analysis. Then adsorption behavior and mechanism of Cr(VI) ions on the obtained materials were investigated with scanning electron microscope, Zeta potential and thermal gravity analysis, etc. The adsorption process was found to follow the pseudo-second order kinetics and 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 electrostatic interaction mechanism, and SO42- in the solution had a great effect on the adsorption process. In addition, high pH and ionic strength could reduce the uptakes of adsorbate, which could be used for desorption of Cr(VI) ions from the gels.