Diverse\nNitrogen Functional Sites Decorated Covalent\nOrganic Framework Nanotrap Boosting Iodine Capture and Gold Recovery

With the development of nuclear energy and the widespread\nuse of\nprecious metals, the threat to the environment and human health from\nradioactive iodine isotopes and metal ions has increased. Therefore,\nthe development of efficient adsorbents for pollutants and precious\nmetals is crucial. Herein, a novel nitrogen-rich covalent organic\nframework (TPDA-DPTA-COF) containing tertiary amines, imine linkages,\nand pyridine units is designed from <i>N</i>,<i>N</i>,<i>N</i>′,<i>N</i>′-tetrakis(4-aminophenyl)-1,4-benzenediamine\n(TPDA) and 2,5-di(pyridin-4-yl)terephthalaldehyde (DPTA). TPDA-DPTA-COF\nexhibits excellent performance in iodine capture (6.85 g g<sup>–1</sup> for I<sub>2</sub> vapor and 2570 mg g<sup>–1</sup> for I<sub>2</sub> solution in <i>n</i>-hexane) and gold recovery\n(3014 mg g<sup>–1</sup> Au(III) in HAuCl<sub>4</sub> solution)\ndue to the nanotrap effect arising from nanoporous nitrogen-rich structure.\nEven in dilute acid leachate from discarded CPUs, TPDA-DPTA-COF exhibits\nexceptional selective extraction ability toward Au(III). The unique\nnanotrap structure makes TPDA-DPTA-COF a powerful adsorbent for iodine\nand Au(III), which paves promising application in nuclear waste treatment\nand resource recovery.