As a significant metal ion in the environmental and biological systems, excess or shortage of Fe3+ from the organism can cause a host of diseases. So it is very urgent to explore an explicit, rapid and recoverable method for the detection of Fe3+ ions. Herein, a novel and flexible ligand containing 12 carboxyl groups (BHM-COOH) is used for the structure of a series of luminescent Eu3+/Tb3+-metal-organic frameworks (MOFs). A reliable and convenient luminescent detection platform is constructed by combining polylactic acid (PLA) film with Eu0.24Tb0.76-BHM-COOH. More importantly, the luminescent platform can highly sensitive to sense Fe3+ ions through fluorescence quenching (Stern-volmer constant Ksv = 1.27 × 104 M-1 for Fe(NO3)3), and detection limit can be as low as 4.47 μM. The sensing mechanism is ascribed to the fluorescence quenching caused by the competitive absorption between Eu0.24Tb0.76-BHM-COOH and Fe3+ ion. At the same time, the sensor can be reused many times. These exciting results indicate that Eu0.24Tb0.76-BHM-COOH film can serve as a promising multi-responsive luminescent sensor for environmental pollutant monitoring.
Keywords: Bimetallic Ln-MOFs; Fe(3+) ion detection; Fluorescent probe; Luminescent sensor.
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