Experimental and theoretical study on selenite uptake to zirconium metal−organic frameworks: Effect of defects and ligands
Experimental and theoretical study on selenite uptake to zirconium metal−organic frameworks: Effect of defects and ligands
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金属锆有机骨架吸收亚硒酸盐的实验和理论研究：缺陷和配体的影响
DOI：
10.1016/j.cej.2017.08.038
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发表时间：
2017
影响因子：
15.1
通讯作者：
Wang Xiangke
中科院分区：
文献类型：
--
作者：
Li Jie;Liu Yang;Wang Xiangxue;Zhao Guixia;Ai Yuejie;Han Bing;Wen Tao;Hayat Tasawar;Alsaedi Ahmed;Wang Xiangke
成功设计了六核锆金属有机骨架（Zr6MOFs），具有不同种类和含量的缺陷，并研究了其对Se（VI）氧离子捕获的重要影响。zr6节点上的可置换配体（水基和羟基）和弱结合“封盖”配体（Cl−、O2C-CH3−、O2C-CF3−或O2C-CHF2−、HO−和/或H2O）可以通过阴离子交换机制被Se（VI）氧阴离子取代。随着缺失连接缺陷和缺失簇缺陷密度的增加，Se（VI）氧离子的吸收效率更高、速度更快。实验结果和理论密度泛函数理论（DFT）计算表明，较小的HO−、Cl−或H2O补偿配体比O2C-CH3−、O2C-CF3−或O2C-CHF2−补偿配体更容易被取代。基于DFT计算，Se（VI）氧离子对缺陷UiO-66的结合能远高于其他重金属对mof的结合能。此外，在制备zr6mof时，采用调制器合成策略可以更好地提高去除能力，而不是使用太复杂和昂贵的较长的有机连接体合成它们。实验结果和理论计算预示了缺陷可调谐mof作为重金属离子修复应用的有前途的候选物的巨大潜力，因为它们可以大规模、低价格地合成，也可以优雅地定制。
Hexanuclear zirconium metal–organic frameworks (Zr6MOFs) were successfully designed to possess different kinds of defects with various contents and its important influence on the capture of Se(VI) oxyanions was studied. The displaceable ligands (aqua and hydroxy groups) and weak-binding “capping” ligands (Cl−, O2C-CH3−, O2C-CF3−or O2C-CHF2−, HO−and/or H2O) on Zr6nodes could be substituted by Se(VI) oxyanions via a mechanism of anion-exchange. More efficient and faster uptake of Se(VI) oxyanions was obtained with the increase of the densities of both missing linker defects and missing cluster defects. Experimental findings as well as theoretical density functional theory (DFT) calculations disclosed that smaller HO−, Cl−, or H2O compensating ligands can be more easily substituted than the O2C-CH3−, O2C-CF3−or O2C-CHF2−compensating ligands. Based on DFT calculations, the binding energy of Se(VI) oxyanions toward defective UiO-66 is much higher than that of other heavy metals toward MOFs. Moreover, using modulator synthetic strategy in the preparation of Zr6MOFs can be a better choice for enhancing the removal capacity than synthesizing them with longer organic linkers which are too complex and expensive. The experimental results and theoretical calculations prefigure the great potentials of defect-tunable MOFs as promising candidates in the application of heavy metal ion remediation because they can be synthesized in large scale at low price and can also be elegantly tailored.