Yu Cai-Xia, Jiang Wen, Zhang Cheng-Wei, Fang Han, Wang Le-Zun, Gao Ming-Jun, Zhou Yan-Li, Qian Yong, Liu Lei-Lei
School of Environmental and Material Engineering, Yantai University, Yantai 264005, P. R. China.
State Key Laboratory of Nuclear Resources and Environment, East China University of Technology, Nanchang, Jiangxi 330013, P. R. China.
Inorg Chem. 2024 Aug 12;63(32):15105-15114. doi: 10.1021/acs.inorgchem.4c02148. Epub 2024 Jul 30.
The efficient and complete extraction of uranium from aqueous solutions is crucial for safeguarding human health from potential radiotoxicity and chemotoxicity. Herein, an ultrathin 2D metal-organic framework (MOF) nanosheet with cavity structures was elaborately constructed, based on a calix[4]arene ligand. The large molecular skeleton and cup-shaped feature of the calix[4]arene enabled the as-prepared MOFs with large layer separations, which can be readily delaminated into ultrathin single-layer (∼1.25 nm) nanosheets. The incorporation of permanent cavity structures to the MOF nanosheets can fully utilize their structural features of readily accessible adsorption groups and exposed surface area in uranium removal, reaching ultrafast adsorption kinetics; the functionalized cavity structure endowed MOF nanosheets with the ability to preconcentrate and extract uranium from aqueous solutions with ultrahigh efficiencies, even at extremely low concentrations. As a result, relatively high removal ratios (>95%) can be achieved for uranium within 5 min, even in the ultralow concentration range of 75-250 ppb, and the residual uranium was reduced to below 4.9 ppb. The MOF nanosheets also exhibited extremely high anti-interference ability, which could efficiently remove the low-level uranium (∼150 ppb) from various real samples. The characterizations and density functional theory calculations demonstrated that the synergistic effects of multiple interactions between the carboxylate groups and cage-like cavities with uranyl ions can be responsible for the efficient and selective uranium extraction.
从水溶液中高效、完全地提取铀对于保护人类健康免受潜在的放射性毒性和化学毒性至关重要。在此，基于杯[4]芳烃配体精心构建了一种具有空腔结构的超薄二维金属有机框架（MOF）纳米片。杯[4]芳烃的大分子骨架和杯状特征使得所制备的MOF具有较大的层间距，能够很容易地剥离成超薄的单层（约1.25纳米）纳米片。在MOF纳米片中引入永久性空腔结构可以充分利用其易于接近的吸附基团和暴露表面积的结构特征来去除铀，实现超快的吸附动力学；功能化的空腔结构赋予MOF纳米片以超高效率从水溶液中预浓缩和提取铀的能力，即使在极低浓度下也是如此。结果，即使在75 - 250 ppb的超低浓度范围内，铀在5分钟内的去除率也能达到相对较高的值（>95%），并且残留铀降低到4.9 ppb以下。MOF纳米片还表现出极高的抗干扰能力，能够从各种实际样品中高效去除低水平的铀（约150 ppb）。表征和密度泛函理论计算表明，羧酸根基团与笼状空腔与铀酰离子之间多种相互作用的协同效应可导致高效、选择性地提取铀。
