Introduction of benzotriazole into graphene oxide for highly selective coadsorption of An and Ln: Facile synthesis and theoretical study
Introduction of benzotriazole into graphene oxide for highly selective coadsorption of An and Ln: Facile synthesis and theoretical study
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将苯并三唑引入氧化石墨烯中以实现 An 和 Ln 的高选择性共吸附：简易合成和理论研究
DOI：
10.1016/j.cej.2018.03.114
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发表时间：
2018-07-15
影响因子：
15.1
通讯作者：
Xia, Chuanqin
中科院分区：
文献类型：
--
作者：
Ding, Jie;Tang, Siqun;Xia, Chuanqin
从水溶液中去除锕系元素和镧系元素是放射性废物安全处置的重要策略。本文首次提出了一种5-甲基苯并三氮唑修饰氧化石墨烯（MBTA-GO）吸附剂，该吸附剂以苯并三氮唑基团为靶点，对An-Ln（An和Ln）离子具有较强的吸附能力。采用傅里叶变换红外光谱（FT-IR）、热重分析（TGA）和X射线光电子能谱（XPS）对MBTA-GO进行了表征。结果表明，在多阳离子溶液中，MBTA-GO对金属离子的吸附强烈依赖于pH值，且MBTA-GO对An-Ln具有良好的选择性（选择系数大于99%），是目前报道的绝大多数吸附剂。循环实验表明，MBTA-GO具有良好的可重复使用性和结构稳定性。通过密度泛函理论（DFT）计算，阳离子-MBTA-GO的结合能大小顺序为Th（IV）> U（VI）> Eu（III）> La（III）> Sr（II）> Cs（I），表明苯并三唑基团优先与MBTA-GO上的An-Ln离子发生作用，这与实验结果吻合较好。最后揭示了选择性共吸附的机理是化学络合作用和静电相互作用的协同作用。
The removal of actinide (An) and lanthanide (Ln) elements from aqueous solution is a significant strategy for the safe disposal of radioactive wastes. Herein we presented a 5-methylbenzotriazole modified graphene oxide (MBTA-GO) as a novel adsorbent, in which benzotriazole group was used as targeted sorption site bearing strong affinity toward An-Ln (An and Ln) ions for the first time. MBTA-GO was characterized by Fourier transformed infrared spectroscopy (FT-IR), thermal gravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). The effect of pH and initial concentration on combined adsorption of An-Ln were examined, and the results showed that the adsorption of metal ions on MBTA-GO was strongly dependent on pH in multi-cation solution, and MBTA-GO exhibited excellent An-Ln selectivity (selectivity coefficients are more than 99%), overwhelming majority of other reported adsorbents. The cycle experiments revealed that the MBTA-GO exhibited good reusability and structural stability. By density functional theory (DFT) calculation, the binding energy of Cation-MBTA-GO followed the order of Th(IV) > U(VI) > Eu(III) > La(III) > Sr(II) > Cs(I), suggesting that the benzotriazole groups were preferentially responsible for An-Ln ions on MBTA-GO, which is in well agreement with the experimental results. Finally, the mechanism of selective coadsorption was revealed, which is the synergistic effect of chemical complexation and electrostatic interaction.