Killing two birds with one stone: a simple and integrated platform based on an Fe-MOF for dual-mode detection and photocatalytic elimination of tetracycline

The persistence of tetracycline (TC) antibiotic residues in foodstuffs and aquatic systems poses critical threats to human health and the ecological environment, driving an imperative demand for developing multifunctional platforms capable of simultaneous visual monitoring and high-efficiency elimination of these contaminants. Herein, a simple yet novel colorimetric sensor that integrates detection and degradation of TCs has been constructed based on the excellent peroxidase-like activity of the metal-organic frameworks (MOFs) MIL-101(Fe). Colorless 3,3',5,5'-tetramethylbenzidine (TMB) can be effectively oxidized to generate blue oxidized TMB (ox-TMB) by MIL-101(Fe), which exhibits a characteristic peak at 652 nm. The presence of TCs at varying concentrations can specifically inhibit this oxidation reaction, leading to different degrees of decrease in the intensity of the characteristic peak. Based on this concentration-dependent chromogenic behavior, TCs are quantitative identified by the dual-mode detection of UV-Vis absorbance and with the naked eye. The as-fabricated colorimetric sensor displays superior selectivity toward TCs, with its detection capability in complex matrices being successfully validated in environmental water and commercial milk samples. To avoid accessional antibiotic contamination, MIL-101(Fe) can also be served as a scavenger to degrade TCs efficiently under visible light irradiation, achieving up to 92.01% removal efficiency within 3 h. The developed strategy has the advantages of visual recognition, rapid field detection and no requirement of large-scale instruments. Most critically, it cleverly realizes the integration of antibiotic detection and degradation, which provides a low-cost and high-efficiency solution to fundamentally solve the problem of antibiotic contamination.