Tailored amphiphilic covalent organic frameworks as efficient adsorbents for per- and polyfluoroalkyl substances removal from water

Per - and polyfluoroalkyl substances (PFAS) constitute a class of persistent environmental pollutants that pose significant risks to ecosystems and human health. This study demonstrates the rational design and synthesis of amphiphilic covalent organic frameworks (COFs) for the efficient and selective removal of PFAS from aqueous environments. Three COF variants, TpPa-COF, TbPa-CF₃-COF, and TpPa-CF₃-COF, were constructed via Schiff base condensation, incorporating tailored hydrophobic and hydrophilic functional groups. Among these, the amphiphilic TpPa-CF₃-COF exhibited exceptional PFOS adsorption capacity (443 mg/g), rapid kinetics, and outstanding reusability, maintaining over 95% removal efficiency in complex natural water matrices. Mechanistic studies revealed that synergistic fluorophilic (F F) and intermolecular hydrogen-bonding interactions drive the highly selective adsorption process. This work extends beyond presenting a superior adsorbent by elucidating the underlying synergistic adsorption mechanism, which provides both a strategic approach to COFs engineering and a general design principle for addressing amphiphilic pollutants in practical water treatment.