Viologen‐Derived Covalent Organic Frameworks: Advancing PFAS Removal Technology with High Adsorption Capacity

Abstract The escalating presence of per‐ and polyfluoroalkyl substances (PFAS) in drinking water poses urgent public health concerns, necessitating effective removal. This study presents a groundbreaking approach, using viologen to synthesize covalent organic framework nanospheres: MELEM‐COF and MEL‐COF. Characterized by highly crystalline features, these nanospheres exhibit exceptional affinity for diverse anionic PFAS compounds, achieving simultaneous removal of multiple contaminants within 30 min. Investigating six anionic PFAS compounds, MEL‐ and MELEM‐COFs achieved 90.0–99.0% removal efficiency. The integrated analysis unveils the synergistic contributions of COF morphology and functional properties to PFAS adsorption. Notably, MELEM‐COF, with cationic surfaces, exploits electrostatic and dipole interactions, with a 2500 mg g −1 adsorption capacity—surpassing all reported COFs to date. MELEM‐COF exhibits rapid exchange kinetics, reaching equilibrium within 30 min. These findings deepen the understanding of COF materials and promise avenues for refining COF‐based adsorption strategies.