Cr(VI) Adsorption on Polyethyleneimine Modified Graphite Oxide

Polyethyleneimine modified graphite oxide (PEI-GO) were prepared by grafting polyethyleneimine (PEI) on the surface of graphite after oxidation and esterification. The structure and surface properties of synthesized composites were characterized by Fourier-transformed infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscope (TEM), Rraman spectroscopy (RS) and X-ray, photoelectron spectroscopy (XPS) analysis, and its adsorption and desorption capability for aqueous Cr (VD was also conducted. Characterization results indicated that polyethyleneimine has been successfully grafted on the surface of graphite oxide, and the content of the amino groups of PEI-GO is 4.36 mmol.g(-1). PEI-GO exhibits high adsorption capacity for aqueous Cap. Adsorption isotherm of CA) onto PEI-GO could be described better by Freundlich model than Langmuir model. The pseudo-second-order kinetics followed the adsorption data very well. Adsorption amount of Cr(VI) onto PEI-GO decreased with increasing pH. The presence of anions in solution resulted in the suppressed CAVI) adsorption, and the effect of different anions was in the order of PO43- > SO42- > NO3- > Cl-. XPS analysis indicates that adsorption coupled chemical reduction mechanism contributes to enhanced CAD adsorption on PEI-GO. After four successive desorption-regeneration cycles, PEI-GO still possesses high adsorption capacity for Cap, which indicates that the adsorbent has good regeneration capability and can be used repeatedly.