Activated carbon from biomass waste as potential materials for uranium removal

Journal article, 2025

This study investigates the synthesis and characterization of two nitrogen-doped activated carbons derived from corn cobs for the removal of uranium (VI) ions from aqueous solutions. The materials were characterized using a range of techniques, including thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and nitrogen adsorption isotherms. Particle size distribution (PSD) was determined through immersion calorimetry, and adsorption performance was evaluated using the Langmuir, Freundlich, and Sips isotherm models. Among these, the Sips model provided the best fit, with maximum adsorption capacities of 51.66, 46.32, and 22.12 mg/g for CCAKN7, CCAK7, and CC, respectively, at 298 K. Adsorption kinetics followed a pseudo-second-order model, reaching equilibrium within 55 min, indicating rapid adsorption. Thermodynamic analysis revealed that the adsorption process was spontaneous and exothermic, with a negative Gibbs free energy and enthalpy change, confirming the feasibility of uranium adsorption. Furthermore, the study demonstrated that nitrogen doping enhances the surface functionality of the activated carbons, significantly improving their uranium uptake compared to unmodified materials. These findings suggest that nitrogen-doped activated carbons from corn cobs are promising candidates for the efficient removal of uranium (VI) from contaminated water sources, contributing to sustainable nuclear waste management.