Gelatin-polyacrylamide double network enhanced polyamidoxime magnetic photothermal composite hydrogel for highly efficient and selective uranium extraction from seawater

The development of adsorbents for highly efficient extraction of uranium from seawater is a crucial for generating nuclear energy. However, their practical application is limited because of low U/V selectivity and recovery difficulties. Herein, we developed a new magnetic photothermal composite hydrogel (Gel-Fe3O4/PAO) adsorbent to facilitate efficient recovery and selective extraction of uranium from seawater. The hydrogel exhibits excellent tensile strength and self-recovery ability owing to the double-network structure formed via the physical crosslinking of gelatin and polymerization of acrylamide (AM). Furthermore, the photothermal conversion performance of Fe3O4 nanoparticles improves the uranium selectivity of PAO and enables magnetic recovery of the hydrogel. Adsorption results show that when the Fe3O4 and gelatin contents are 1.5 wt.% and 16 wt.%, respectively, the hydrogel can be rapidly heated under light, meeting the requirements of high adsorption capacity (515.5 mg·g-1) and selectivity (Kd (U) /Kd (V) = 2.77) for uranium ions. After seven sorption-desorption cycles, the uranium adsorption capacity of the Gel-Fe3O4/PAO hydrogel remains at nearly 89 %. In simulated seawater experiments, the Gel-Fe3O4/PAO hydrogel exhibits excellent impact resistance and a high selective uranium removal rate, demonstrating its considerable potential for practical application in uranium extraction from seawater.