Synthesis and application of carboxymethyl cellulose-graphene oxide composite for the mitigation of Pb2+ and Cd2+ from aqueous solution

Abstract

In this work, carboxymethyl cellulose-graphene oxide (CMC-GO) nanocomposite was prepared and used as a low-cost adsorbent to remove Pb²⁺ and Cd²⁺ from aqueous solution. CMC-GO was characterized using various techniques such as FTIR, XRD, TGA, zeta potential and SEM with EDX. The optimum pH, adsorbent dose, time, and percentage of removal were found 5.0, 1.0 g/L, 60 min, and 96.3% for Pb²⁺ and 5.5, 1.5 g/L, 60 min, and 82.5% for Cd²⁺, respectively at an initial concentration of 200 ppm. The Freundlich isotherm model and pseudo-second order kinetics were configured properly with experimental data and maximum capacity was found 213.21 mg/g and 134.04 mg/g for Pb²⁺ and Cd²⁺ ions respectively. The positive value of enthalpy (ΔH) and negative values of Gibbs free energy (ΔG) for the Cd²⁺ and Pb²⁺ sorption process indicate endothermic nature of sorption and spontaneous at room temperature. This study revealed that the prepared composite could be cost-effective, efficient and viable adsorbent for the remediation of toxic Pb²⁺ and Cd²⁺ pollution from water bodies as well as wastewater treatment.