石墨烯负载纳米零价铁对U（VI）和Tc（VII）吸附与还原的协同去除机理

U and Tc are the multivalent radioactive elements. U(VI) and Tc(VII) can easily transfer in the aqueous environment due to their high solubility, causing easily serious environment hazard. It is difficult to eliminate them with conventional remediation techniques. Because of its excel adsorption capacity and high chemical reactivity, nanoscale zero-valent iron supported on solid is paid attention to pollution control and remediation.In this proposal, the graphene-loaded nanoscale zero-valent iron composites will be prepared by using controlled-plasma-sputtering technique, and and the physical and chemical properties of the composites will be characterized, and optimized by adjusting sputtering process parameters. The composite removal performance by way of the synergism action of adsorption and reduction for the multivalent radioactive elements will be investigated by choosing U(VI) and Tc(VII) as the targets. The composite removal mechanisms by the synergism action of adsorption and reduction for the multivalent radioactive elements will be explained by combining batch experiment and microscopic characterization. The noval technology for the remediation of multivalent radioactive elements will be explored.

铀（U）和锝(Tc)是多价态的放射性元素，U（VI）和Tc(VII)易溶于水，易在水环境中迁移, 极易造成严重的环境危害，采用常规的方法很难将其去除。固体负载纳米零价铁具有优良的表面吸附能力和化学反应活性，在污染治理和修复中备受关注。本项目采用等离子体溅射技术，通过调节溅射工艺参数，在石墨烯表面上负载纳米零铁，可控构筑性能稳定的石墨烯纳米零价铁复合材料，并对该复合材料进行物理、化学特性的表征；以U(VI)和Tc(VII)为目标放射性元素，研究溶液条件对多价态放射性元素在该复合材料上吸附与还原去除效果的影响；采用静态批实验和微观表征相结合，阐述该复合材料对多价态放射性元素吸附与还原的协同去除机理。探索多价态放射性元素治理的新技术。

项目采用H2/Ar等离子体对氧化石墨烯富集来的Fe(II) /Fe(III)离子进行还原制备出纳米零价铁/石墨烯复合材料（NZVI/rGOs）。对所得材料的形貌结构和化学组成进行了表征，研究此复合材料对U(VI), Re(VII), Pb(II)，Cr(VI)等的去除性能, 探究此复合材料对放射性元素的吸附与还原的协同去除效果，研究不同实验条件（如pH值、离子强度、温度、时间等）下，此复合材料对UO22+和ReO4-去除性能的影响；采取宏观批实验与微观表征（如XRD、SEM、TEM、FTIR、XPS和XAFS）相结合，阐述此复合材料对多价态放射性元素吸附与还原的协同去除机理。NZVI/rGOs不仅可以提高纳米零价铁的分散性和稳定性，石墨烯还可能强化电子转移和预浓缩污染物，将石墨烯和纳米零价铁的优势相耦合，提高其对于变价态水溶性很高的放射性元素和金属离子的吸附与还原的协同去除性能。放射性元素和金属离子从NZVI/rGOs解吸以后，可以通过H2/Ar等离子体还原再生NZVI/rGOs。项目研究结果为放射性污染治理提供了新材料和新方法。. 项目的支持下，在Chemical Society Reviews（1篇）, Environmental Science & technology（2篇）, Environmental Science-Nano（5篇）, Journal of Hazardous Material, Chemical Engineering Journal, ACS Sustainable Chemistry & Engineering, The Journal of Physical Chemistry C, Journal of Colloid and Interface Science，中国科学：化学等国际著名学术刊物上发表论文SCI38篇, 其中一区论文22篇，论文被他引450多次。中国科学：化学(英文版)发表在Science China Chemistry 2016, 59 (1) 150–158被选为优秀论文 , 6篇高被引论文（ESI1%）。授权发明专利1项。在Academic Press出版一本英文专著(ISBN 978-0-08-102727-1)。培养研究生7名，毕业博士生3名。