NH2-MIL-53(Al) for simultaneous removal and detection of fluoride anions
Donghua Xie, Xiao Ge, Wenxiu Qin, Yunxia Zhang
Abstract
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.