![]() ![]() By comparison, covalent organic frameworks (COFs) with porous structures and high stability have been demonstrated as potential adsorbents for iodine in vapor and various liquid media. However, MOFs cannot be applied in liquid media, which require a wet-washing process due to their poor water stability. Recently, metal–organic frameworks (MOFs) have been employed to improve porosity and specific surface area. However, these adsorbents usually have small porosity and limited specific surface area thus, it is difficult to achieve the efficient adsorption of gaseous iodine. Bismuth-based compounds and mordenite-containing silver are usually used to adsorb gaseous iodine. For iodine vapor, the main capturing strategy is through physisorption. As-produced radioactive iodine exists in both vapor and liquid forms. The reprocessing condition of nuclear fuels usually requires a high temperature under high pressure. g −1) and high activity that can participate in human metabolism, and the half-life of 129I is as long as 1.57 × 10 7 years, which is the major pollutant endangering human health and ecological environment.131I has high radioactivity (4.6 × 10 15 Bq The 131I and 129I nuclides produced through uranium fission are highly volatile and hazardous. With the emerging employment of nuclear energy, tremendous attention has been paid to the proper disposal and treatment of radioactive pollutants. This study provides a guide for the future molecular design strategy toward novel iodine adsorbents. Remarkably, PyT-1 presents an excellent maximum adsorption capacity (0.635 g g −1), and the adsorption limit of PyT-2 is 0.445 g g −1 in an n-hexane solution with an iodine concentration of 400 mg L −1, which is highly comparable to the state-of-the-art iodine absorption performance. At ambient conditions, PyT-1 and PyT-2 both exhibit good adsorption properties for iodine capture either in a gaseous or liquid medium. ![]() Compared with the topology (PyT-2) with an AA stacking form, the topology (PyT-1) with an AB stacking form has more twisted pore channels and complex ink-bottle pores. The two COFs both have high crystallinity, high specific surface area, and excellent chemical and thermal stability. Herein, two polymorphic COFs with significantly different crystalline structures are obtained based on the same building blocks with varied molecular ratios. However, the detailed structure–property relationship of COFs in iodine adsorption remains elusive. The various pore structures of covalent organic frameworks (COFs) render them promising candidates for efficient iodine adsorption. Radioactive iodine-capturing materials are urgently needed for the emerging challenges in nuclear waste disposal. ![]()
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