Kinetic, isotherm and thermodynamic studies for removal of methyl orange using a novel β-cyclodextrin functionalized graphene oxide-isophorone diisocyanate composites

Abstract

A novel β-cyclodextrin functionalized graphene oxide-isophorone diisocyanate composite (GO-IPDI-CDs) was prepared with graphene oxide (GO), isophorone diisocyanate (IPDI) and β-cyclodextrin (β-CD) as raw materials. The structure and morphology of GO-IPDI-CDs were characterized by Fourier transform infrared spectroscopy (FT-IR), Brunauer–Emmett–Teller (BET), Raman, scanning electron microscopy (SEM), X-ray diffractometer (XRD) and thermogravimetric analysis (TG). The GO-IPDI-CDs was applied to deal with wastewater solution containing dye of methyl orange. The effects of environment factors (such as temperature, pH and so on) to methyl orange adsorption were investigated in details. The results showed that GO-IPDI-CDs has a highest adsorption efficiency of 92.88% and adsorption capacity of 83.40mg/g at the optimum conditions (0.020g/mL of dosage of GO-IPDI-CDs, temperature of 45°C, a time of 2.5h and pH=6.0). Adsorption kinetics, adsorption isotherm and adsorption thermodynamic were investigated. Pseudo second-order kinetics equation can describe the adsorption process appropriately. Langmuir and Freundlich isotherm models were used to simulate the equilibrium data and the results showed that the equilibrium data were close to Langmuir model. The thermodynamic parameters indicated that the adsorption process was endothermic. The proposed method has been successfully applied to adsorb methyl orange in water samples with satisfactory result.