Europium-doped zirconium-based metal-organic framework NU-1000: Discrimination, ratiometric detection, and adsorptive removal of tetracycline antibiotics.

The increasing environmental contamination by tetracycline antibiotics (TCs) necessitates efficient detection and removal strategies. This study presents the development of a bifunctional material, Eu-NU-1000, which integrates ratiometric fluorescence detection and high-capacity adsorption of TCs. The material is constructed by doping europium ions (Eu3+) into the zirconium-based metal-organic framework (MOF) NU-1000, offering a dual-channel fluorescence response for selective TCs detection and enhanced adsorption performance. Eu-NU-1000 enables highly sensitive and selective detection of TCs through ratiometric fluorescence at 617 and 472 nm, the detection mechanism was based on antenna effect and photoinduced electron transfer, with a low limit of detection (LOD): 22.14 nM for tetracycline and 11.83 nM for oxytetracycline. Furthermore, the material exhibits a high adsorption capacity of 440.6 mg·g-1 for tetracycline, surpassing several existing MOF-based adsorbents. The study also investigates the adsorption mechanisms, including electrostatic interactions, coordination chelation, and π-π stacking, which collectively contribute to the exceptional tetracyclin removal efficiency of Eu-NU-1000. The material maintains over 80% adsorption efficiency after five regeneration cycles, highlighting its reusability and practical applicability in environmental remediation.