Mechanistic insights into Cu(Ⅱ) removal from aqueous solution by Camellia oleifera shell–reduced graphene oxide

Abstract

The Cu(II) pollution in aquatic environment is becoming a severe health challenge due to its non-biodegradable nature. In this study, for the first time, reduced graphene oxide (rGO) was prepared by Camellia oleifera shell (COS) extract in a low-cost and environmentally friendly way and successfully applied for the removal of Cu(II) ion from aqueous solutions. An 85.7% removal efficiency was achieved when the initial concentration of Cu(II) was 10 mg/L with a COS-reduced graphene oxide (COS-rGO) dosage of 0.5 g/L, pH of 5.1, and experimental temperature of 20 °C. To propose a mechanism for the removal of Cu(II) using the COS-rGO, characterization tests as well as thermodynamic and kinetics analyses of the COS-rGO adsorption of Cu(II) were systematically performed. The following major inferences were derived from the results of this study: i) The adsorption of Cu(II) using COS-rGO obeyed pseudo-second-order kinetics as a spontaneous endothermic reaction. ii) According to the results of characterization by using Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD), it was confirmed that the removal of Cu(II) by COS-rGO was a result of chemical adsorption following a rate-controlled process and Langmuir model was applied to this adsorption process. Therefore, it can be expected that the green synthesis of COS-rGO has potential to be a cost-effective adsorbent for removing Cu(II) from water, which has excellent prospects for waste utilization and pollutant reduction.

Date of Award	Mar 2022
Original language	English
Awarding Institution	University of Nottingham
Supervisor	Jun He (Supervisor) & Yong Sun (Supervisor)