Selective sensing of Fe3+ ions in aqueous solution by a biodegradable platform based lanthanide metal organic framework

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. A series of bimetallic lanthanide metal-organic frameworks were synthesized by solvothermal method based a novel and flexible ligand containing 12 carboxyl groups (BHM-COOH), and a reliable and convenient luminescent detection platform was constructed by combining PLA film with Eu0.24Tb0.76-BHM-COOH. The fluorescence platform exhibited good selectivity, high sensitivity, and low limit of detection for Fe3+ ion in aqueous solution, which could be utilized for the detection of environmental pollution, and will have a good application prospect. [Display omitted] •A series of bimetallic Ln-MOFs have been designed and synthesized successfully based on a novel ligand.•This flexible ligand containing 12 carboxyl groups, which can be coordinated with 12 Eu3+/Tb3+ ions at the same time.•A reliable luminescent platform was constructed based Ln-MOFs to detection of Fe3+ ions in aqueous solution.•These sensors can be utilized to detect Fe3+ ions due to high sensitivity and low limitation of detection.