Ultra-stable fluorescent 2D covalent organic framework for rapid adsorption and selective detection of radioiodine

Radioactive iodine is a harmful substance produced by nuclear fission, and its hazard to the human body should not be underestimated. In this work, a novel adsorbent COF-PA containing quinoline and phenylacetylene units for dual chemical adsorption of iodine is designed and prepared. It exhibits the fastest adsorption rate (1.3 g h−1) among 2D covalent organic frameworks and also possesses remarkable adsorption capacity and efficiency at low concentration of iodine vapor. When the weight ratio of adsorbent to iodine is 1:1, the adsorption efficiency of COF-PA reaches 90%. Moreover, COF-PA can maintain good crystallinity when soaked in common organic solvents and strong acids (12 M HCl) and bases (14 M NaOH) for one week, and its stability is of great significance for the real industrial applications. Unexpectedly, COF-PA shows strong fluorescence, which can be specifically quenched by iodine and thus be applied for selective iodine detection.