Rapid and selective removal of fluoroquinolone antibiotics from aqueous environments by a dual-functional composite membrane of sulfonated fluorine-based COF/Carboxymethyl cellulose fiber

Bifunctional synergistic interactions afford highly selective quadruple-site adsorption toward fluoroquinolones. • Hierarchical mesoporous structure enables rapid adsorption equilibrium within merely 20 min. • The integrated membrane structure facilitates facile separation and outstanding cyclic stability. • Desirable removal efficiency is achieved in untreated natural water and practical wastewater. • The membrane exhibits broad-spectrum removal capacity toward various fluoroquinolone antibiotics. Fluoroquinolone antibiotics (FQs) persist in aquatic environments due to high stability, causing ecological and health risks by promoting drug-resistant strains. Efficient purification technologies are thus urgently needed. However, existing adsorbents have critical flaws: single-functionalization cannot achieve both high capacity and selectivity, while powders agglomerate, are hard to recover, and show slow kinetics and poor anti-interference ability. To solve this, this study prepared a bifunctional composite membrane (SO 3 H-FCOF@CMCF) by in-situ growth of fluorinated covalent organic framework on carboxymethyl cellulose fiber and sulfonation, realizing “dual-functionalization + membrane morphology” synergy. Fluorine atoms enhance selective affinity via F–F interactions, and –SO 3 H groups increase adsorption capacity through electrostatic and hydrogen bonding. Their synergy forms a four-way adsorption mechanism, improving selectivity and stability. The material reaches adsorption equilibrium in 20 min, with maximum adsorption capacities of 305.45–358.64 mg g −1 for norfloxacin, ciprofloxacin and enrofloxacin. It keeps over 90% capacity after six cycles and shows strong resistance to pH changes, high salt, coexisting ions and natural organic matter. In raw well water, tap water, and commercially bottled water, the material achieves over 85% FQs removal efficiency, demonstrating robust practical applicability. This study provides an efficient and convenient dual-functional membrane material solution for FQs pollution control. Download: Download high-res image (166KB) Download: Download full-size image