High-performance ratiometric fluorescence detection and removal of tetracycline in milk based on CDs@ZSM-5:Eu3

Abstract

Exploring materials with the dual functionality of detecting and removing tetracycline (TC) residues is crucial because of the environmental and health risks posed by antibiotic overuse. This study introduces a dual-emissive luminescent probe, CDs@ZSM-5:Eu³⁺, created through a solvent-free method combined with subsequent Eu³⁺ion exchange. The nanocomposite's blue emission, originating from carbon dots (CDs), is quenched by TC via an internal filtering effect, while an antenna effect triggers a strong red fluorescence of a TC-Eu³⁺chelate. The ratiometric fluorescence changes in CDs@ZSM-5:Eu³⁺ endow a self-calibrated sensing mechanism for TC, offering a low detection limit of 5.04 nM and a broad detection range of 0.01-50 μM. Demonstrated in real milk samples, the probe exhibits high selectivity and accuracy in detecting TC. The nanocomposite also displayed an impressive TC removal capacity of 238.1 mg g^-1 in water, ascribing to the enrichment and electrostatic attraction effects of ZSM-5 toward TC molecules. This research offers a facile strategy for constructing multifunctional zeolite-based hybrids for simultaneous TC detection and removal from aqueous solutions.

Keywords: Adsorption; Europium functionalized CDs@ZSM-5; Ratiometric fluorescence sensor; Tetracycline.