A Carbazole-Functionalized Porous Aromatic Framework for Enhancing Volatile Iodine Capture via Lewis Electron Pairing

Nitrogen-rich porous networks with additional polarity and basicity may serve as effective adsorbents for the Lewis electron pairing of iodine molecules. Herein a carbazole-functionalized porous aromatic framework (PAF) was synthesized through a Sonogashira-Hagihara cross-coupling polymerization of 1,3,5-triethynylbenzene and 2,7-dibromocarbazole building monomers. The resulting solid with a high nitrogen content incorporated the Lewis electron pairing effect into a pi-conjugated nano-cavity, leading to an ultrahigh binding capability for iodine molecules. The iodine uptake per specific surface area was similar to 8 mg m(-2) which achieved the highest level among all reported I-2 adsorbents, surpassing that of the pure biphenyl-based PAF sample by ca. 30 times. Our study illustrated a new possibility for introducing electron-rich building units into the design and synthesis of porous adsorbents for effective capture and removal of volatile iodine from nuclear waste and leakage.

Automated summary

In this study, nitrogen-rich porous networks with additional polarity and basicity were successfully synthesized as effective adsorbents for the Lewis electron pairing of iodine molecules. The incorporation of Lewis electron pairing effect into a pi-conjugated nano-cavity resulted in ultrahigh binding capability for iodine molecules. Furthermore, introducing electron-rich building units into the design and synthesis of porous adsorbents showed potential for effective capture and removal of volatile iodine from nuclear waste and leakage.