Microporous covalent organic frameworks via flexible units and rich heteroatoms for gas uptake and radioactive iodine uptake

Abstract

Covalent organic frameworks (COFs) are an emerging class of nano-crystalline polymers known for their outstanding chemical stability, exceptionally high surface area, and highly ordered structures, making them ideal candidates for gas capture applications. In particular, the two imine-linked FM-COFs possess a versatile, microporous architecture integrated with nitrogen-rich heteroatoms. These heteroatoms are evenly distributed throughout the structure, from the walls to the linkers, enhancing gas interaction and improving adsorption efficiency. Owing to these advantages, FM-COFs demonstrated a carbon dioxide capacity of 82.6 cm³ g⁻¹ at 273 K and an iodine uptake of 3.98 g g⁻¹ at 350 K. The synergistic effect of microporosity and heteroatom functionality makes these COFs highly effective for selective gas adsorption and radioactive iodine uptake.