Fabrication and Characterization of Sustainable Chitosan-Based Porous Adsorbents for Efficient Removal of Thorium Ions

In this study, an efficient and eco-friendly chitosan/Fe3O4/bentonite (Ch-Fe3O4-Bent) ternary hybrid adsorbent scaffold is developed for the efficient removal and recovery of Th(IV) from contaminated water, facilitating sustainable environmental remediation. The developed scaffold promotes circular economy principles through the recovery of valuable actinide resources while reducing secondary waste generation and mitigating the environmental impacts associated with radioactive wastewater. The crucial radioactive thorium has drawn a lot of attention, and many substances used in numerous industrial operations are thorium isotopes. This paper describes the synthesis of a chitosan hybrid scaffold for thorium adsorption purposes. Many characterization methods were performed on the fabricated scaffold. Removal of thorium (IV) from aqueous media using a Ch-Fe3O4-Bent ternary scaffold was comprehensively investigated through batch experiments under different operational parameters. Thorium adsorption was evaluated as a function of contact time, solution pH, initial thorium concentration, and temperature. The adsorption data were fitted to nonlinear Langmuir, Freundlich, and Temkin isotherm models to evaluate the material’s thorium removal capacity. Among the isotherm models tested, the Langmuir model provided the best fit for thorium adsorption (R2 = 0.88039), while the kinetic data followed the pseudo-second-order model (R2 = 0.99322, qe = 199.61407 mg/g). Based on the nonlinear Langmuir isotherm, the chitosan scaffold composite exhibited a maximum removal capacity (qmax) of 204.80984 mg/g. The thermodynamic feasibility of the adsorption process was evaluated, and the results confirm that the chitosan scaffold serves as a highly effective sorbent for the recovery and adsorption of Th(IV) ions from aquatic environments. Furthermore, this chitosan scaffold can be used to remove radioactive Th(IV) from surface water, seawater, and wastewater generated by nuclear fuel production technologies, mining operations, and laboratories handling radioactive materials. Temperature-dependent studies showed that Th(IV) adsorption occurs spontaneously at room temperature and becomes more favorable at elevated temperatures, indicating an endothermic process. Additionally, the fast adsorption kinetics of Th(IV) onto the chitosan scaffold render it highly attractive for the scale-up of thorium extraction. Overall, the findings highlight the potential of the developed chitosan scaffold as an environmentally sustainable and cost-efficient adsorbent for radioactive wastewater treatment, contributing to cleaner production, efficient resource utilization, environmental conservation, and the advancement of sustainable nuclear technologies.