Constructing “breathing” dynamic skeletons with extra π-conjugated adsorption sites for iodine capture†
Radioiodine (129I and 131I) emission from the nuclear waste stream has aroused enormous apprehension because of its quick diffusion and radiological contamination. Conventional porous adsorbents such as zeolites and carbon with rigid skeletons and constant pore volumes reveal a limited performance for reliable storage. Here, a series of soft porous aromatic frameworks (PAFs) with additional π-conjugated fragments is disclosed to serve as physicochemical stable media. Due to the flexibility of the tertiary amine center, the PAF products provide sufficient space for the binding sites, and thus exhibit a considerable capability for iodine capture from both gaseous and soluble environments. The obtained capacity of PAFs is ca. 1.6 times higher than that of PAF-1 which possesses similar aromatic constituents featuring an ultra-large specific surface area (BET = 5600 m2 g−1). The novel paradigm of dynamic frameworks is of fundamental importance for designing adsorbents to treat environmental pollution issues.