Colloidal templating of highly ordered porous amidoxime-functionalized hydrogel for intelligent treatment of uranium contaminated water

Abstract

A smart hydrophilic amidoxime-functionalized porous colloidal crystal hydrogel has been successfully constructed for intelligent treatment of uranium contaminated water. • Hydrophilic amidoxime-functionalized porous colloidal crystal hydrogel is developed. • Amidoxime groups are introduced to improve the adsorption efficiency and selectivity. • HAPCCH can realize visual and on-site UO 2 2+ detection without other signal molecules. • HAPCCH shows good regeneration and performs well in real water samples. Uranium is the key element in the nuclear industry, but it often triggers serious risk when discharged into the natural environment. It is extremely urgent to construct a novel material that can realize intelligent treatment of uranium contaminated water. To this end, a hydrophilic amidoxime-functionalized porous colloidal crystal hydrogel (HAPCCH) is developed in this work for the effective adsorption and detection of uranyl ion (UO 2 2+ ). HAPCCH with merits of abundant specific UO 2 2+ -binding sites of amidoxime ligands and excellent hydrophilicity achieves to a maximum adsorption capacity of 2.52 mmol g −1 . The HAPCCH performs well for UO 2 2+ removal in real water samples and shows good regeneration. In addition, sensitive and selective detection of UO 2 2+ can be easily realized by recording the diffraction shift or observing the color change of HAPCCH, achieving a detection limit of 10 nM. The density functional theory (DFT) calculation results reveal that the lower binding free energy and Gibbs free energy of HAPCCH to UO 2 2+ contribute to the better selectivity compared to other ions. The result indicates that this absorbent material holds great potential application in the water pollution control.