COMPOSITES OF CHITOSAN AND GRAPHENE OXIDE: EFFICACY IN CADMIUM (Cd²⁺) REMOVAL FROM INDUSTRIAL EFFLUENT

Abstract This study evaluates the effectiveness of a Chitosan-Graphene Oxide (CGO) composite for the elimination of cadmium (Cd²⁺) ions from industrial wastewater. The CGO adsorbent was prepared via a modified Hummers method and was characterized through FTIR, XRD, and SEM techniques. Spectral analysis by FTIR demonstrated the presence of ionizable functional groups essential for adsorption, while XRD results indicated the existence of crystalline phases, including quartz, orthoclase, and aragonite. SEM imaging revealed a uniform dispersion of chitosan nanoparticles across graphene oxide sheets. The modifications notably improved the composite's surface area and increased the number of available active sites. Batch adsorption experiments were conducted to assess the influence of several factors, including contact time, pH, temperature, and adsorbent dosage, on the removal of Cd²⁺.The optimal conditions identified 120 minutes of contact time, 0.5 g of adsorbent, pH 10.0, and a temperature of 373 K yielded a maximum removal efficiency of 99.83%. Isotherm studies revealed that the process of adsorption conformed to Freundlich, Temkin, and Dubinin-Radushkevich models, indicating the formation of multiple adsorption layers on non-uniform surfaces. Kinetic analysis revealed that the Pseudo-second-order model provides the most accurate representation of the data. Additionally, intra-particle diffusion emerged as a contributing factor, although it was not identified as the only rate-limiting step. Thermodynamic evaluations revealed that the adsorption process demonstrated characteristics of spontaneity and endothermic behavior, accompanied by an increase in disorder at the solid-liquid interface. These findings position the CGO composite as a notably efficient, eco-friendly, and sustainable option for cadmium elimination from wastewater, highlighting its promising applications in industrial water treatment processes.