An Amidoxime Porphyrin-Based\nPorous Hyper-Cross-Linked\nPolymer for Efficient Uranium Extraction from Aqueous Solution

Nuclear energy, as an efficient and clean energy source,\nhas been\nwidely used in recent years, and the extraction of uranium from water\nresources is of great significance. Herein, a porphyrin-based hyper-cross-linked\npolymer with functional amidoxime groups (HCP-TPP-AO; TPP = tetraphenyl\nporphyrin, AO = amidoxime group) was successfully prepared and used\nfor uranium adsorption. Owing to its abundant porous morphology and\nthe strong chelation of amidoxime/TPP groups to uranium, HCP-TPP-AO\nremoved 94.2% of uranium ions from aqueous solutions. The kinetic\nbehavior of uranium adsorption on HCP-TPP-AO was comprehensively investigated\nand was consistent with the kinetic process dominated by chemical\nadsorption. HCP-TPP-AO also preferentially adsorbed U(VI) rather than\nother competing ions and exhibited a distribution coefficient (<i>K</i><sub>d</sub>) of up to 8.12 × 10<sup>4</sup> mL/g.\nFurthermore, the HCP-TPP-AO adsorbent could maintain 84.6% of its\nadsorption capacity after seven reuse cycles without any changes in\nits chemical structure or porous morphology. Electrostatic potential\n(ESP) analysis and adsorption calculations proved that amidoxime groups\nand TPP units in the polymer network of HCP-TPP-AO made a great contribution\nto the U(VI) adsorption capacity.