Robust self-floating covalent organic framework/chitosan aerogels for the efficient removal of sulfamerazine

Covalent organic framework (COF) aerogels have attracted significant interest due to their broad range of potential applications. However, synthesizing COF aerogels with tailored structures and robust mechanical stability remains a formidable challenge. In this work, we present a double-cross-linking strategy to prepare a series of compressible COF/chitosan (COF/CS) aerogels under mild conditions. By harnessing chemical cross-linking and physical interactions, such as electrostatic and hydrogen bonding, ionic COF powders containing sulfonic acid groups (i.e., TpPa-SO3H) are immobilized and connected with CS, forming a three-dimensional interconnected network. Impressively, the ratio of COF to CS and the size of the COF/CS aerogels can be easily controlled by adjusting the processing parameters. The resulting COF/CS aerogels possess a highly porous structure and low density, enabling the aerogels to self-float and facilitating practical applications and recycling. Due to these remarkable characteristics, TpPa-SO3H/CS aerogel demonstrates excellent adsorption capacity, effectively removing sulfamerazine from aqueous solutions with an adsorption capacity of 102.5 mg·g−1. Moreover, the aerogel can be reused in three adsorption–desorption cycles without significant capacity loss. This proposed method offers a facile, eco-friendly, and scalable approach for producing highly compressive COF-based aerogels, thereby accelerating the practical utilization of COFs and contributing to environmental remediation.