Graphene oxide enhanced adsorption capacity of chitosan/magnetite nanocomposite for Cr(VI) removal from aqueous solution

In this work, we propose a simple method for preparing of Fe3O4/graphene oxide/chitosan (FGCs) nanocomposite and its application for removal of Cr(VI) from aqueous solution by adsorption process. The advantages of this adsorbent that it can be recovered by an external magnet as well as it can be regenerated. For that, FGCs nanocomposite has been synthesized co-precipitation method and synthesized FGCs has been characterized by x-ray diffraction (XRD), Fourier-Transform Infrared spectroscopy (FT-IR), vibrating sample magnetometer (VSM), Transmission Electron Microscopy (TEM), Field Emission Scanning Electron Microscopy (FESEM) and Energy Dispersive x-ray spectroscopy (EDX). The sorption efficiency of FGCs was evaluated by adsorption Cr(VI) ions from aqueous solution to optimize contents in FGCs adsorbent material and also for adsorption process. The results shown that the adsorption of Cr(VI) on FGCs can be reached to maximal with the content of FGCs is 68 wt% of Fe3O4 nanoparticles, 2 wt% of graphene oxide (GO) and 30 wt% of chitosan (CS) (sample FGCs-68/2/30). The adsorption process was carried out at pH3 (pH = 3) with the contact time ca. 40 min and dosage of adsorbent around 0.04 mg.mL(-1) . The adsorption isotherm fits the Langmuir model with adsorption capacity of FGCs-68/2/30 for Cr(VI) is 200 mg.g(-1). In addition, the reusability of FGCs nanocomposite was tested and about 75% of removal efficiency was obtained after 6 cycles. Therefore, the FGCs nanocomposite has a good stability and may be a promising material for removal of heavy metal ions from aqueous solution to clean up the environment.