Efficient extraction of uranium (VI) from aqueous solution by Zr/Ce-UiO-66-NH2 modified by dual strategies of bimetallization and amination

We modified Zr/Ce-UiO-66-NH2 using dual bimetallization and amination strategies to efficiently extract uranium from water resources. XRD, FTIR, and XPS indicated the successful alteration of material amination. Moreover, the metal Zr was partially replaced by Ce in Zr-oxygen atom clusters in Zr/Ce-UiO-66-NH2. It possessed commendable structural stability in acidic and alkaline solutions. Irrespective of whether it was submerged in a 6 M strong acid or in a 0.5M strong base solution, the structural integrity of Zr/Ce-UiO-66-NH2 remained unaffected. Batch experiments at pH = 6.0 revealed that uranium adsorption by Zr/Ce-UiO-66-NH2 reached 376.8mgg(-1) and 611.33mgg(-1) at 298 K and 328 K, respectively. These values are much better than those obtained using bimetallic-modified Zr/Ce-UiO-66 or amine-functionalized UiO-66-NH2. After five consecutive sorption and desorption cycles, the material retained a uranium removal rate of more than 80%, proving its excellent regenerative properties. Kinetic modeling of U(VI) adsorption on Zr/Ce-UiO-66-NH2 implied that chemisorption dominated the rapid uranium sorption rate. We propose potential adsorption mechanisms involving three interactions: inner-sphere surface complexation, chemisorption, and electrostatic interactions. This study shows that the dual strategies of bimetallization and amination can effectively enhance U(VI) extraction from water. This approach has potential applications for the structural design of uranium adsorbents.