An Efficient Uranium Adsorption Magnetic Platform Based on Amidoxime-Functionalized Flower-like Fe3O4@TiO2 Core–Shell Microspheres

Efficient removal of uranium (U) from aqueous solutions is crucial for ecological safety. Functionalized magnetic nanoparticles provide a promising strategy for radionuclide recovery and separation. However, designing and synthesizing magnetic adsorbents with high sorption capacity and selectivity, accompanied by excellent stability and reusability, remain a challenge. In this work, novel amidoxime-functionalized flower-like magnetic Fe3O4@TiO2 core–shell microspheres are designed and synthesized to efficiently remove U(VI) from aqueous solutions and actual seawater. The magnetic Fe3O4 core facilitates easy separation by an external magnetic field, and flower-like TiO2 nanosheets provide abundant specific surface areas and functionalization sites. The grafted amidoxime (AO) groups could function as a claw for catching uranium. The maximum adsorption capacity on U(VI) of the designed nanospheres reaches 313.6 mg·g–1 at pH 6.0, and the adsorption efficiency is maintained at 97% after 10 cycles. In addition, the excellent selectivity of the magnetic recyclable AO-functioning Fe3O4@TiO2 microspheres endows the potential of uranium extraction from seawater. The designed material provides an effective and applicable diagram for radioactive element elimination and enrichment.