Investigation of adsorption properties and mechanism of uranium(VI) and europium(III) on magnetic amidoxime-functionalized MCM-41

Herein, a novel magnetic amidoxime-functionalized MCM-41 (Fe3O4@MCM-41-PDA/OA) was developed by loading Fe3O4 on amidoxime-functionalized MCM-41 via a simple strategy. The microscopic surface morphologies and structures of the as-synthesized composites were analyzed various physicochemical and spectroscopic techniques, while the experimental parameters were optimized by means of the single factor experimental methodology to improve the removal efficiency of uranium(VI) and europium(III) on Fe3O4@MCM-41-PDA/OA. The static adsorption test showed that the saturated adsorbed amounts for uranium(VI) and europium(III) were 38.11 mg/g and 25.36 mg/g, respectively. Meanwhile, the adsorption isotherm and kinetics studies revealed that elimination of the two radionuclides were a monolayer and chemisorption process, whereas the calculated thermodynamic parameters suggested that the adsorption of the two radionuclide was spontaneous and feasible. The SEM and XPS analysis conformed that immobilization of the two radionuclides was fulfilled through the binding interactions between U(VI)/Eu(III) and the amino, phenolic hydroxyls and amidoxime groups on the surface of Fe3O4@MCM-41-PDA/OA. This work provided a simple and cost-effective way to separation and enrichment of radionuclides from contaminated water.