Highly Sensitive and Selective Uranium Detection in Natural Water Systems Using a Luminescent Mesoporous Metal–Organic Framework Equipped with Abundant Lewis Basic Sites: A Combined Batch, X-ray Absorption Spectroscopy, and First Principles Simulation Investigation

Abstract

Uranium is not only a strategic resource for the nuclear industry but also a global contaminant with high toxicity. Although several strategies have been established for detecting uranyl ions in water, searching for new uranium sensor material with great sensitivity, selectivity, and stability remains a challenge. We introduce here a hydrolytically stable mesoporous terbium(III)-based MOF material compound 1, whose channels are as large as 27 Å × 23 Å and are equipped with abundant exposed Lewis basic sites, the luminescence intensity of which can be efficiently and selectively quenched by uranyl ions. The detection limit in deionized water reaches 0.9 μg/L, far below the maximum contamination standard of 30 μg/L in drinking water defined by the United States Environmental Protection Agency, making compound 1 currently the only MOF material that can achieve this goal. More importantly, this material exhibits great capability in detecting uranyl ions in natural water systems such as lake water and seawater with pH being adjusted to 4, where huge excesses of competing ions are present. The uranyl detection limits in Dushu Lake water and in seawater were calculated to be 14.0 and 3.5 μg/L, respectively. This great detection capability originates from the selective binding of uranyl ions onto the Lewis basic sites of the MOF material, as demonstrated by synchrotron radiation extended X-ray adsorption fine structure, X-ray adsorption near edge structure, and first principles calculations, further leading to an effective energy transfer between the uranyl ions and the MOF skeleton.

An Ultrafast Molecular‐Rotor‐Based Fluorescent Turn‐On Sensor for the Perrhenate Anion in Aqueous Solution

“…Note that the iodide anion leads to quenching of the ThT emission, which can be attributed to its very‐well‐known heavy‐atom effect. In addition to these anions, natural water also contains various metal cations that may affect the fluorescence properties of ThT. Thus, we have also evaluated the response of ThT towards various environmentally abundant cations such as Na + , Ca 2+ , Zn 2+ , Mg 2+ , Cu 2+ , Sr 2+ , and Al 3+ , none of which led to any significant increase in ThT fluorescence (see Figure S6 in the Supporting Information).…”

Highly Selective Recovery of Lanthanides by Using a Layered Vanadate with Acid and Radiation Resistance

“…Theadsorption of Eu 3+ can be further confirmed by EXAFS spectra (Supporting Information, Table S1 and Figure S5). [23] There is ap reedge peak at about 6985 eV which dominates the X-ray absorption, indicating that europium is trivalent in 1-Eu. [3b] Versus the free EuCl 3 ·6 H 2 O, the radial distribution functions of Fourier transform data of 1-Eu is different.…”

Extraction of Metal Ions with Metal–Organic Frameworks

“…Uranium has been extracted from natural water samples with a hydrolytically stable mesoporous terbium(III)-based luminescent mesoporous MOF equipped with abundant Lewis basic sites [88]. High sensitivity and selectivity were achieved in real lake samples, where there is a huge excess of potentially interfering ions.…”