Efficient removal of uranium from aqueous solution by zero-valent iron nanoparticle and its graphene composite
Efficient removal of uranium from aqueous solution by zero-valent iron nanoparticle and its graphene composite
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零价铁纳米粒子及其石墨烯复合材料高效去除水溶液中的铀
DOI：
10.1016/j.jhazmat.2015.02.028
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发表时间：
2015-06-15
影响因子：
13.6
通讯作者：
Shi, Wei-Qun
中科院分区：
文献类型：
--
作者：
Li, Zi-Jie;Wang, Lin;Shi, Wei-Qun
制备了零价铁纳米粒子（ZVI-np）及其石墨烯复合物，并将其应用于缺氧条件下的铀去除。结果表明，ZVI-nps可以完全清除24 ppm U（VI）的溶液，无论NaHCO 3、腐殖酸、模拟地下水组分的存在与否，也不管溶液pH值从5到9的变化，都显示出ZVI-nps在可渗透反应屏障（PRB）中修复铀污染地下水的潜力。在最大吸附量的测定中，当C-0（U）= 643 ppm时，铀的去除率为100%，当C-0（U）= 714 ppm时，ZVI-nps的饱和吸附量为8173 mg U/g。通过SEM、XRD、XANES和（NH 4）（2）CO 3溶液中化学浸出的研究，对反应机理进行了探讨。当铁离子充足时，U（VI）以U3 O 7形式部分还原沉淀;当铁离子不足时，U（VI）在表面的水解沉淀将占主导地位，其特征是Fe 2+离子的释放。Fe-0核的溶解被认为是U（VI）（氢）氧化物连续形成的驱动力。结果表明，石墨烯载体的引入可提高铀的去除速率和还原率，有利于铀在地球化学环境中的长期固定。(C)2015 Elsevier B. V.版权所有。
Zero-valent iron nanoparticle (ZVI-np) and its graphene composites were prepared and applied in the removal of uranium under anoxic conditions. It was found that solutions containing 24 ppm U(VI) could be completely cleaned up by ZVI-nps, regardless of the presence of NaHCO3, humic acid, mimic groundwater constituents or the change of solution pH from 5 to 9, manifesting the promising potential of this reactive material in permeable reactive barrier (PRB) to remediate uranium-contaminated groundwater. In the measurement of maximum sorption capacity, removal efficiency of uranium kept at 100% until C-0(U) = 643 ppm, and the saturation sorption of 8173 mg U/g ZVI-nps was achieved at C-0(U) = 714 ppm. In addition, reaction mechanisms were clarified based on the results of SEM, XRD, XANES, and chemical leaching in (NH4)(2)CO3 solution. Partially reductive precipitation of U(VI) as U3O7 was prevalent when sufficient iron was available; nevertheless, hydrolysis precipitation of U(VI) on surface would be predominant as iron got insufficient, characterized by releases of Fe2+ ions. The dissolution of Fe-0 cores was assigned to be the driving force of continuous formation of U(VI) (hydr)oxide. The incorporation of graphene supporting matrix was found to facilitate faster removal rate and higher U(VI) reduction ratio, thus benefitting the long-term immobilization of uranium in geochemical environment. (C) 2015 Elsevier B.V. All rights reserved.