Efficient separation of uranium in solution by ZnFe2O4 doped with TiO2: Adsorption behaviors and mechanism study

The spinel composite doped with TiO2 (TiO2@ZnFe2O4) was prepared via in situ fabrication and template method to extract uranium(VI) from solution. Compared with ZnFe2O4 and TiO2/ZnFe2O4, TiO2@ZnFe2O4 showed a high adsorption efficiency (98.3%) and adsorption capacity (716.2 mg g(-1)), which mainly related to the uniform porous structure of TiO2@ZnFe2O4. After five adsorption-desorption cycles, the removal efficiency of TiO2@ZnFe2O4 remained above 90%, indicating that TiO2@ZnFe2O4 had excellent reusability. Besides, TiO2@ZnFe2O4 possessed excellent adsorption selectivity for uranium(VI) in the exis-tence of competitive ions. The Langmuir adsorption model and pseudo-second order model fitted well the adsorption process, which demonstrated that the remove behavior of uranium(VI) on TiO2@ZnFe2O4 was a monolayer chemisorption process. The extraction behavior of TiO2@ZnFe2O4 for uranium(VI) was mainly attributed to electrostatic attraction, complexation reaction and oxygen vacancy filling. This study not only provides a high efficiency adsorbent (TiO2@ZnFe2O4) for the extraction of uranium(VI) from solution but also offers a new effective way to enhance the performance of spinel composite. (C) 2022 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.