Adsorption of Quaternized-chitosan-modified Reduced Graphene Oxide

Abstract

A novel quaternized-chitosan-modified reduced graphene oxide (HACC-RGO) combined the adsorption advantages of RGO and 2-Hydroxypropyltrimethyl ammonium chloride chitosan (HACC). The adsorption property of HACC-RGO sheets for methyl orange (MO) was demonstrated and compared with RGO and HACC. The removal ratios of HACC-RGO sheets reached 92.6% for MO after a 24 h adsorption. The adsorption kinetics, isotherms and thermodynamics were investigated to indicate that the kinetics and equilibrium adsorptions were well-described by pseudo-second-order kinetic and Freundlich isotherm model, respectively. The thermodynamic parameters suggested that the adsorption process was spontaneous and endothermic in nature. Moreover, monodisperse HACC-RGO/CS beads were fabricated by the microfluidic method. The adsorption and desorption of HACC-RGO/CS beads for MO were studied. After three adsorption-desorption cycles, the adsorption capacity remained above 55% and the desorption capacity was not below 70%. The HACC-RGO/CS beads can be reused and have great potential applications in removing organic dyes from polluted water.

Keywords

reduced graphene oxide / chitosan / adsorption / adsorption kinetic