Camellia oleifera shell–reduced graphene oxide for adsorption of copper(II)

Copper pollution in aquatic environments poses a significant health challenge due to its non-biodegradable nature. This study introduces a novel and environmentally friendly approach to preparing Camellia oleifera shell extract reduced graphene oxide (COS-rGO) for the effective removal of Cu(II) from aqueous solutions. By using a 0.5 g/L dosage of COS-rGO at a pH of 5.1 and a temperature of 20 °C, an 85.8 % removal efficiency (18.7 mg/g) of Cu(II) was achieved at an initial concentration of 10 mg/L. Various characterization techniques, including Fourier-transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD), were employed to examine the synthesized COS-rGO. Additionally, thermodynamic and kinetic studies were conducted to investigate the mechanism of Cu(II) adsorption on COS-rGO. The results demonstrate that the adsorption of Cu(II) on COS-rGO follows pseudo-second-order kinetics, representing a spontaneous exothermic reaction. Our findings further support that the removal of Cu(II) by COS-rGO is driven by chemical adsorption in accordance with the rate-controlled process based on the Langmuir adsorption model. Overall, this study presents the green synthesis of COS-rGO as a promising technique for producing a cost-effective adsorbent from waste materials, which can be utilized for the mitigation of heavy metals in water.