NH2-MIL-53(Al) for simultaneous removal and detection of fluoride anions

To address the limitations of the separate fluoride removal or detection in the existing materials, herein, amino-decorated metal organic frameworks NH2-MIL-53(Al) have been succinctly fabricated by a sol-hydrothermal method for simultaneous removal and determination of fluoride. As a consequence, the proposed NH2-MIL-53(Al) features high uptake capacity (202.5 mg/g) as well as fast adsorption rate, being capable of treating 5 ppm of fluoride solution to below the permitted threshold in drinking water within 15 min. Specifically, the specific binding between fluoride and NH2-MIL-53(Al) results in the release of fluorescent ligand NH2-BDC, conducive to the determination of fluoride via a concentration-dependent fluorescence enhancement effect. As expected, the resulting NH2-MIL-53(Al) sensor exhibits selective and sensitive detection (with the detection limit of 0.31 µmol/L) toward fluoride accompanied with a wide response interval (0.5−100 µmol/L). More importantly, the developed sensor can be utilized for fluoride detection in practical water systems with satisfying recoveries from 89.6% to 116.1%, confirming its feasibility in monitoring the practical fluoride-contaminated waters.