| Hexavalent chromium [Cr (Ⅵ)] is highly toxic and solutble, once entered the aquatic environment, Cr(Ⅵ) becomes a huge threat to humans, animals and plants due to its high toxicity and extreme solubility in aquatic system. Generally, Cr(Ⅵ) is treated via chemical reduction/precipitation, ion exchange, membrane separation and adsorption. Among these, adsorption is one of the most economical and technically feasible approaches. Recently, more researches focus on new adsorbents for the removal of Cr(Ⅵ)Graphene, is a one-atom-thick planar sheet of sp2-bonded carbon atoms that are densely packed in a honeycomb crystal lattice. It has been reported for wildly applications in wastewater remediation and this materials has shown promising potential. Dual-functionalized reduced graphene oxide (RGO) composites have been successfully synthesized by introducing poly(diallyldimethylammonium chloride)(PDDA) and magnetic CoFe2O4particles to the surface of RGO sheets via the reduction process of graphene oxide (GO) to RGO in the presence of PDDA, followed by the hydrothermal treatment of inorganic salts. Characterization results show that the as-prepared RGO-PDDA-CoFe2O4composites remain layered structure feature, and the CoFe2O4nanoparticles uniformly dispersed on the surface of RGO-PDDA sheets. Such RGO-PDDA-CoFe2O4composites exhibit excellent adsorption ability of Cr(VI) removal. The Cr(VI) removal capability reaches maximum up to265.5mg/g, which is24.8%higher than that of RGO-CoFe2O4and far larger than the previously reported values from other nanomaterials. Interestingly,69.7%of the up-taken Cr(VI) was reduced to less toxic and soluble Cr (III). The adsorption kinetics study reveals that the adsorption of Cr(VI) from aqueous solution over RGO-PDDA-CoFe2O4composites follows pseudo-second-order kinetic model. The dual-functionalized composites with the distinct advantages mentioned above serve as ideal candidates for aqueous environmental remediation. |
PDF Full Text Request