Designed sulfonate-based covalent organic frameworks with dual functions of recognition and encapsulation

Abstract

Seeking novel materials with simultaneous task-specific recognition and enrichment for trace pollutants is of great significance for environmental security. Here, we developed a sulfonate-based covalent organic framework (sCOF) for the fast detection of tetracycline hydrochloride (TCH). For the first time, we visually demonstrated by molecular simulation that the incorporation of disulfonic acid in COF facilitates self-exfoliation due to multiple roles of fluorophore, steric hindrance and interlayered water receptor. The exfoliated fluorescent covalent organic nanosheets (f-sCON) exhibit superior sensitivity to TCH residuals in aqueous solution and can be engineered into a naked-eye fluorescent device of f-sCON-gel. Owing to the high capacity and rapid kinetics of bulk sulfonate-COF towards TCH, simultaneous TCH removal and detection are achieved in a continuous flow mixed column of sulfonate-COF adsorbent and f-sCON-gel. We believe this facile self-exfoliation provides a promising strategy for simultaneously achieving the long-sought-after dual functions of recognition and encapsulation in one system.