Sustainable selenium ions adsorption of cyclodextrin and cellulose functionalized layered double hydroxide/reduced graphene oxide nanocomposites

In this study, we synthesized the β-Cyclodextrin (CD) and Carboxymethyl Cellulose (CC) functionalized LDH/rGO nanocomposites for the efficient uptake of selenium ions at a neutral pH. The surface morphology and physical properties of the nanocomposites were characterized using X-Ray Diffraction (XRD), High-Resolution Transmission Electron Microscopy (HRTEM), Energy-Dispersive X-Ray Spectroscopy (EDAX), Fourier-Transform Infrared Spectroscopy (FTIR), and N₂ adsorption-desorption analysis. Equilibrium adsorption experiments were carried out to optimize crucial parameters such as contact time (60–360 min), adsorbent dosage (0.01–0.1 g/L), and pH (2−11) for efficient selenium ion removal. Kinetic and isotherm studies were conducted to analyze the sorption performance of the nanocomposites. The Langmuir isotherm model provided an excellent fit for the adsorption data (R² ≥ 0.99), confirming the monolayer adsorption of selenium ions on the adsorbent surface. The maximum adsorption capacity of CC and CD composites was calculated for Se (IV) adsorption as 248.75 mg g⁻¹ and 275.48 mg g⁻¹, for Se (VI) adsorption as 153.37 mg g⁻¹ and 169.64 mg g⁻¹. Additionally, adsorption kinetics was assessed using the pseudo-second-order model, yielding high correlation coefficients (R² ≥ 0.98). Moreover, the adsorption mechanism, regeneration ability, and the impact of co-existing anions were investigated. Our findings demonstrate the effectiveness of the CD and CC incorporated LDH/rGO biocomposites in selenium ion removal.