2D Benzothiophene-Based Covalent Organic Frameworks for Efficient Iodine Capture.

The leakage of iodine and its radioactive isotopes poses a major threat to ecosystems and human health, emphasizing the need for effective and recyclable iodine capture materials. Covalent organic frameworks (COFs), characterized by high surface areas, tunable pore sizes, and excellent chemical stability, are ideal candidates for adsorption applications. Herein, two novel COFs (JUC-700 and JUC-701) are designed and synthesized based on benzotrithiophene (BTT). Both JUC-700 and JUC-701 exhibit high surface areas (2004.9 and 1990.5 m² g^-1, respectively), mesoporous structures (≈2.6 nm), and abundant heteroatoms, contributing to their exceptional iodine capture performance. Notably, JUC-701 demonstrates superior adsorption capacity (6.17 g g^-1) compared to JUC-700 (4.73 g g^-1), attributes to the enhanced iodine affinity near its pyridine groups. Theoretical calculations further reveal that the pyridinic nitrogen in JUC-701 significantly strengthens interactions with iodine molecules, confirming its superior capture capabilities. This study provides insights into the design of functionalized COFs for iodine capture, contributing to advanced materials for environmental remediation and nuclear waste management.