Cross-linked chitosan anchoring on magnetic nanosorbent for efficient eliminating of uranium (VI): equilibrium, kinetic, and thermodynamic studies

The Fe₃O₄/TiO₂/Chitosan nanocomposite was synthesized under optimized pH conditions, which facilitate the reaction between glutaraldehyde and chitosan to form a cross-linked layer on Fe₃O₄/TiO₂/. Prepared composite served as a magnetically separable and environmentally friendly adsorbent for the remediation of uranium (VI). Uranium (VI) adsorption adhered to pseudo-second-order kinetics and aligned closely with the Langmuir isotherm, demonstrating a maximum uptake capacity of 40.00 mg/g. Thermodynamic analysis suggested an endothermic, spontaneous nature for uranium (VI) adsorption. Kinetic and thermodynamic analyses revealed that chemisorption predominates, facilitated by the diverse functional groups of cross-linked chitosan, which effectively chelate uranium (VI) ions.

Applying glutaraldehyde, a layer of cross-linked chitosan was created on the surface of TiO₂@Fe₃O₄ binary oxide to provide a thermodynamically evidenced chemical adsorbent for uranium removal at practical pH. The adsorption of uranium (IV) on TiO₂@Fe₃O₄@chitosan followed the pseudo-second-order model. The homogeneous distribution of active sites on the sorbent was confirmed by fitting the data with the Langmuir isotherm.