Understanding the Bonding Nature of Uranyl Ion and Functionalized Graphene: A Theoretical Study
Understanding the Bonding Nature of Uranyl Ion and Functionalized Graphene: A Theoretical Study
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了解铀酰离子和功能化石墨烯的键合性质：理论研究
DOI：
10.1021/jp500924a
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发表时间：
2014
影响因子：
2.9
通讯作者：
Shi Wei-Qun
中科院分区：
文献类型：
--
作者：
Wu Qun-Yan;Lan Jian-Hui;Wang Cong-Zhi;Xiao Cheng-Liang;Zhao Yu-Liang;Wei Yue-Zhou;Chai Zhi-Fang;Shi Wei-Qun
研究铀酰离子与氧化石墨烯（GO）之间的成键性质对于理解GO基材料去除放射性废水中铀的机理具有重要意义。利用密度泛函理论结合准相对论小核赝势方法优化了22个铀酰离子与GO的配合物。研究的含氧官能团包括羟基、羧基、酰胺基和二甲基甲酰胺。结果表明，与中性GO配合物（铀酰/GO）相比，阴离子GO配合物（铀酰/GO-/2-）中GO的铀原子与氧原子之间的距离（U-OG）更短。铀酰/GO-/2-配合物中氢键的形成可以增强阴离子GO对铀酰离子的结合能力。此外，热力学计算表明，在溶液中的吉布斯自由能的变化是相对更负的络合反应有关的羟基和羧基官能化的阴离子GO络合物。因此，几何构型和热力学能量表明，铀酰离子对羟基和羧基修饰的GO的结合能力比酰胺基和二甲基甲酰胺基修饰的GO强得多。这项研究可以为设计新的纳米材料，可以有效地去除放射性废水中的放射性核素提供见解。
Studying the bonding nature of uranyl ion and graphene oxide (GO) is very important for understanding the mechanism of the removal of uranium from radioactive wastewater with GO-based materials. We have optimized 22 complexes between uranyl ion and GO applying density functional theory (DFT) combined with quasi-relativistic small-core pseudopotentials. The studied oxygen-containing functional groups include hydroxyl, carboxyl, amido, and dimethylformamide. It is observed that the distances between uranium atoms and oxygen atoms of GO (U–OG) are shorter in the anionic GO complexes (uranyl/GO–/2–) compared to the neutral GO ones (uranyl/GO). The formation of hydrogen bonds in the uranyl/GO–/2–complexes can enhance the binding ability of anionic GO toward uranyl ions. Furthermore, the thermodynamic calculations show that the changes of the Gibbs free energies in solution are relatively more negative for complexation reactions concerning the hydroxyl and carboxyl functionalized anionic GO complexes. Therefore, both the geometries and thermodynamic energies indicate that the binding abilities of uranyl ions toward GO modified by hydroxyl and carboxyl groups are much stronger compared to those by amido and dimethylformamide groups. This study can provide insights for designing new nanomaterials that can efficiently remove radionuclides from radioactive wastewater.