Incorporation Phytic acid-modified chitosan/sodium alginate melamine sponge composite for highly efficient uranium...

The fabrication of composite materials that exhibit facile separability while retaining exceptional adsorption capacity for uranium adsorption remains a challenge. In this study, phytic acid-modified chitosan/sodium alginate@melamine sponge composite (PCSS@MS) was successfully fabricated via a cross-linking approach. The obtained PCSS@MS was applied to evaluate the adsorption properties for uranium from solutions. SEM and XRD characterization confirmed the material's stable three-dimensional porous architecture. The adsorption experiments revealed that PCSS@MS demonstrates highly uranium adsorption capability across a broad pH range, achieving a maximum adsorption capacity of 297.86 mg g^-1 at 318 K. PCSS@MS exhibited >95 % U(VI) removal efficiency at 200 mg/L under optimal conditions (pH = 5, 298.15 K, 80 mg). Furthermore, the adsorbent retained a remarkable 70.8 % uranium removal rate after four consecutive adsorption-desorption cycles. The adsorption behavior was consistent with the pseudo-second-order model and Temkin isotherm model, indicating the existence of multiple adsorption sites on the surface and the chemisorption process. FTIR and XPS analyses revealed that phosphate groups played a dominant role in U(VI) binding, with auxiliary contributions from amino, carboxyl, and hydroxyl groups. The synergistic coordination among these functional groups enhanced uranium adsorption abilities. These findings highlight PCSS@MS as a promising adsorbent for efficient uranium extraction from aqueous solutions.