Encapsulating covalent organic frameworks (COFs) in cellulose aerogels for efficient iodine uptake

Abstract

Efficient capture and storage of radioiodine are of great importance for developing nuclear energy and tackling nuclear waste, which however remain challenging due to the scarcity of powerful materials. In this work, we rationally design and fabricate a hybrid material by encapsulating covalent organic frameworks (COFs) into ultralight cellulose aerogels for efficient iodine (I2) capture. Two kinds of functionalized cellulose precursors that can be covalently cross-linked are synthesized. Solvothermally synthesized COF particles with a uniform diameter of ∼ 500 nm are then introduced into the precursors followed by freeze drying to produce hybrid aerogels. With the presence of rich and ordered micropores afforded by COFs, these highly porous aerogels exhibit excellent organic solvent absorption performances and high uptake capacities toward solvent-dissolved and vaporized I2. More importantly, in view of the processable and robust structure, we realize the shaping of hybrid aerogels into aerogel columns to effectively capture I2 vapor and I2 solute in continuous operations. Therefore, this work not only provides a new way to shape COF materials but also could inspire the design of viable platforms for high-performance I2 capture.