Amino-functionalized graphene oxide for Cr(VI), Cu(II), Pb(II) and Cd(II) removal from industrial wastewater

Abstract

Amino-functionalized graphene oxide (GO-NH2) was synthesized by grafting (3-aminopropyl) triethoxysilane on the graphene oxide (GO) surface. The GO-NH2 with high surface area and numerous active sites can efficiently adsorb Cr(VI), Cu(II), Pb(II) and Cd(II) ions. The maximum adsorption capacities of GO-NH2 for Cr(VI), Cu(II), Pb(II) and Cd(II) were 280.11, 26.25, 71.89 and 10.04 mg g-1, respectively. The pseudo-first-order and pseudo-second-order kinetic models were employed to describe the kinetic processes. The experimental data agreed well with the pseudo-second-order kinetic equation, and the adsorption of heavy metals onto GO-NH2 occurs via chemical adsorption. The characteristics of Cr(VI), Cu(II), Pb(II) and Cd(II) in the GO-NH2 adsorption processes were analyzed using the Langmuir and Freundlich isotherm models. The adsorption processes of Pb(II) and Cd(II) on GO-NH2 were fit by the Langmuir model. The Freundlich isotherm model was well correlated to Cr(VI) and Cu(II). The GO-NH2 is a promising material for the removal of heavy metal ions from industrial wastewater. This study provides an effective pathway to process industrial wastewater, and the GO-NH2 has a good adsorption effect for the treatment of heavy metals in industrial wastewater.