Amidoxime-functionalized metal-organic frameworks UiO-66 for U(VI) adsorption from aqueous solution

In order to improve the U(VI) adsorption capacity of the metal-organic frameworks UiO-66 in the acidic water environment, UiO-66-AO nanocrystals were synthesized on the basis of literature for the first time. Scanning electron microscopy and Fourier transform infrared spectra revealed that the successful synthesis of UiO-66-AO nanoparticles. The UiO-66-AO nanocomposites were used to remove U(VI) from aqueous solution. UiO-66-AO showed the effective adsorption of U(VI) compared to UiO-66 in the acidic environment and Fe3O4@SiO2-AO in the neutral or alkaline environment, respectively. The adsorption isotherms of the nanocomposites could be described very well by the Freundlich equation with ultra-high maximum adsorption capacity of 227.8 mg/g. The synergistic effect of the amidoxime group and the metal-organic frameworks UiO-66 has great significance for the extraction of U(VI) from seawater and industrial wastewater.