Benzotriazole decorated graphene oxide for efficient removal of U(VI)
Benzotriazole decorated graphene oxide for efficient removal of U(VI)
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苯并三唑修饰氧化石墨烯可有效去除 U(VI)
DOI：
10.1016/j.envpol.2019.06.109
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发表时间：
2019-10-01
影响因子：
8.9
通讯作者：
Xia, Chuanqin
中科院分区：
文献类型：
--
作者：
Ding, Jie;Yan, Zijun;Xia, Chuanqin
需要开发用于从核废水中捕获铀的高效材料。在这里，5-甲基苯并三唑改性的氧化石墨烯（MBTA-GO）用于从水溶液中吸附U（VI）。通过不同条件的试验，发现酸性溶液中U（VI）的去除与pH值有很强的依赖性，而与离子强度无关。U（VI）的吸附符合准二级动力学，吸附等温线可用Langmuir模型拟合。在pH为3.5时，对U（VI）有较高的去除能力（q（max）= 264 mg/g）。XPS、EXAFS分析和密度泛函理论（DFT）计算表明，MBTA-GO对铀的捕获机理是：（i）苯并三氮唑和羧基（提供孤对电子）的表面络合作用;（ii）由于电子从石墨烯片转移到苯并三氮唑，提高了三氮唑基团离域π键对铀的协同配位能力。DFT计算进一步表明，与羧基相比，苯并三唑显示出与U（VI）更强的结合，这是由于[侧/表面-U-MBTA-GO]（79.745，54.986 kcal/mol）的结合能高于[MBTA-GO-COOH -U]（27.131 kcal/mol）。这项工作将为设计新型含氮吸附剂在废水处理中的实际应用提供有价值的见解。(C)2019爱思唯尔有限公司版权所有。
There is a need to develop highly efficient materials for capturing uranium from nuclear wastewater. Here, 5-methylbenzotriazole modified graphene oxide (MBTA-GO) was used to adsorb U(VI) from aqueous solution. By the trials of different conditions, we found that the removal of U(VI) from acidic solution was strongly dependent on pH but independent of ionic strength. The U(VI) adsorption was perfectly conformed to the pseudo-second-order kinetics and the adsorption isotherms were simulated by the Langmuir model well. A high removal capacity (q(max) = 264 mg/g) for U(VI) at pH 3.5 was obtained. XPS, EXAFS analyses and DFT calculations revealed that the mechanism of uranium capture was ascribed to (i) the surface complexation by benzotriazole and carboxyl groups (providing lone pair electrons) on MBTA-GO and (ii) enhanced synergistic coordination ability of delocalized pi-bond of triazole group toward U due to the transfer of electrons from graphene sheet to benzotriazole. DFT calculations further demonstrated that benzotriazole displayed stronger binding with U(VI) compared to carboxyl group due to higher binding energy of [Side/Surface-U-MBTA-GO] (79.745, 54.986 kcal/mol) than [MBTA-GO-COOH -U] (27.131 kcal/mol). This work will provide valuable insight into designing novel nitrogen-containing adsorbents for practical application in wastewater treatment. (C) 2019 Elsevier Ltd. All rights reserved.