A fluorinated star-shaped covalent organic framework for efficient iodine adsorption

Covalent organic frameworks (COFs) are widely used for gaseous radioiodine capture through distinctive properties. Herein, 2D fluorinated imine COF (JLNU-316) was designed and constructed in this study. JLNU-316 exhibited large BET surface area of 596.25 mg 2 /g and pore size (2.74 and 3.78 nm), excellent thermal and chemical stability. The adsorption of iodine by JLNU-316 reached 4.08 g/g, which exceeded most of the current fluorine-containing porous iodine adsorption materials. Furthermore, the iodine adsorption capacity remains at 99 % after seven days of exposure to air conditions, and JLNU-316 maintains stable performance following ten cycles. The introduction of heteroatoms enhanced the stability of JLNU-316 and enriched the adsorption sites, thereby increasing the iodine adsorption capacity. This study guides for the design and preparation of novel iodine adsorbents.