A water-stable cyano-functionalized metal-organic framework as an efficient adsorbent of uranyl ion

The water-stable UiO-66 was functionalized by grafting the cyano group of adiponitrile on coordinatively unsaturated Zr(IV) centers, yielding cyano-UiO-66 (UiO-66-CN) through a facile coordination-based post-synthetic modification strategy (PSM). The obtained sample was characterized by thermogravimetric analysis (TGA), infrared spectrometry (IR), scanning electron microscopy (SEM) and powder x-ray diffraction spectrometry (PXRD), which confirm the successful modification of cyano groups and the preservation of crystal structure. UiO-66-CN exhibits excellent adsorption performance for uranyl ion from water with maximum adsorption capacity of 10.6 mg g(?1), which is five times as high as the pristine UiO-66 at the initial concentration of 5.0 mg l(?1). Moreover, the adsorbed uranyl ion can be easily desorbed with 0.1 mol l(?1) HCl elution and the prepared material also displays a desirable selectivity toward U(VI) in a solution containing a series of divalent competing ions. This work establishes a simple and energy efficient route via the PSM strategy to synthesize a novel type of cyano functionalized metal-organic framework for U(VI) ions extraction from solution.