Efficient and selective sensing of Cu2+ and UO22+ by a europium metal-organic framework.

Abstract We report here the investigation of using a luminescent europium organic framework, [Eu 2 (MTBC)(OH) 2 (DMF) 3 (H 2 O) 4 ]·2DMF·7H 2 O (denoted as compound 1), for detecting of both Cu2+ and UO 2 2+ with high sensitivity. Based on the spectroscopy analysis, compound 1 could selectively respond to Cu2+ and UO 2 2+ ions among other selected monovalent, divalent, trivalent metal cations based on a turn-off mechanism. The detection limit of compound 1 towards Cu2+ ion was as low as 17.2 μg/L, which is much lower than the maximum tolerable concentration of Cu2+ in drinking water (2 mg/L) defined by United States Environmental Protection Agency. On the other hand, the detection limit towards UO 2 2+ ions is 309.2 μg/L, which could be used for detecting uranium in relative severely contaminated areas. The concentration-dependent luminescence intensity evolution process could be fully understood by the absorption kinetics and isotherm investigations. Furthermore, the quenching mechanism was elucidated by the UV-vis, excitation, luminescence, and lifetime studies. Compound 1 , as the first MOF based luminescence probe for both Cu2+ and UO 2 2+ ions, provides insight into developing MOF-based multifunctional sensors for both nonradioactive and radioactive elements. Graphical abstract fx1 Highlights • A new lanthanide metal organic framework was used for both radioactive UO 2 2+ and nonradioactive Cu2+ detection. • The detection limits toward UO 2 2+ and Cu2+ are 17.2 ppb and 309.2 ppb respectively. • The material could be used for directly detecting UO 2 2+ and Cu2+ contamination in a wide concentration range. • The detection mechanism was systematically investigated by bath experiments, spectroscopy and lifetime studies. [ABSTRACT FROM AUTHOR]