An Amidoxime Porphyrin-Based Porous Hyper-Cross-Linked Polymer for Efficient Uranium Extraction from Aqueous Solution

Nuclear energy, as an efficient and clean energy source, has been widely used in recent years, and the extraction of uranium from water resources is of great significance. Herein, a porphyrin-based hyper-cross-linked polymer with functional amidoxime groups (HCP-TPP-AO; TPP = tetraphenyl porphyrin, AO = amidoxime group) was successfully prepared and used for uranium adsorption. Owing to its abundant porous morphology and the strong chelation of amidoxime/TPP groups to uranium, HCP-TPP-AO removed 94.2% of uranium ions from aqueous solutions. The kinetic behavior of uranium adsorption on HCP-TPP-AO was comprehensively investigated and was consistent with the kinetic process dominated by chemical adsorption. HCP-TPP-AO also preferentially adsorbed U(VI) rather than other competing ions and exhibited a distribution coefficient (Kd) of up to 8.12 × 104 mL/g. Furthermore, the HCP-TPP-AO adsorbent could maintain 84.6% of its adsorption capacity after seven reuse cycles without any changes in its chemical structure or porous morphology. Electrostatic potential (ESP) analysis and adsorption calculations proved that amidoxime groups and TPP units in the polymer network of HCP-TPP-AO made a great contribution to the U(VI) adsorption capacity.