Selective removal of fluoroquinolone antibiotics via molecular recognition: Sub-2 nm ultrathin WO3−x quantum wire-based membrane adsorbents

Environmental residues of fluoroquinolone antibiotics have become a major threat to both ecosystems and human health, necessitating the development of highly efficient adsorbents with molecular recognition capabilities. This study presents a novel class of WO 3− x quantum wire (QWs) designed to address the limitations of traditional adsorbents, particularly poor selectivity and difficult regeneration processes. We successfully fabricated sub-2 nm ultrathin WO 3− x QWs with enriched with W 5 + /W 6+ active sites and surface functional groups through a precise solvothermal method. The resulting WO 3−x QWs demonstrated exceptional selectivity for fluoroquinolone antibiotics, achieving > 90 % removal efficiency for ciprofloxacin, norfloxacin, and ofloxacin, in contrast to much lower removal rates for common dyes like rhodamine B and methylene blue, as well as other antibiotics like tetracycline hydrochloride. Comprehensive characterizations, including thermodynamic and kinetic models, revealed three key molecular recognition mechanisms driving this high performance. Furthermore, when incorporated into a composite membrane, the QWs demonstrated outstanding performance in continuous filtration, showing high removal efficiency, rapid adsorption, and long-term stability. This study not only provides a new class of efficient adsorbent materials for antibiotic treatment, but also offers fresh insights into the development of functional materials with molecular recognition properties for broader applications.