PEI/SA-PAO double crosslinked network gel spheres composites for uranium extraction from seawater

The development of simple and effective strategies for uranium extraction from seawater is crucial to addressing the energy crisis. In this study, we designed and prepared PEI/SA-PAO composite gel spheres with double cross-linking networks, based on a synergistic approach combining polyelectrolyte self-assembly and supramolecular cross-linking. The composite gel spheres utilized sodium alginate (SA) and polyethyleneimine (PEI) as polyelectrolyte substrates, which self-assembled into a primary network through electrostatic interactions. Calcium ions (Ca 2+ ) were then used as a cross-linking agent to construct a supramolecular network. The resulting hierarchical macroporous structure within the gel spheres facilitated the diffusion and mass transfer of uranyl ions. The carboxylate, amino, and amidoxime groups within the material exhibited a high adsorption capacity of 467.56 mg/g in an 8 ppm uranyl solution through a synergistic coordination-chelation effect. After four cycles, the gel material retained an adsorption capacity of 342.54 mg/g. The material also demonstrated excellent selectivity for uranyl ions in natural seawater, achieving uranium adsorption of 5.6 mg/g, underscoring its significant potential for practical application in uranium extraction from seawater.