多孔氧化石墨烯复合材料对重金属蒸气的吸附研究

Lead bismuth eutectic (LBE) is considered as the main candidate coolant for Accelerator Driven Sub-critical System (ADS). However, the Polonium (Po) contained radioactive heavy metal vapor releasing from the LBE is strongly related to the safety of the lead-based reactor. This project intends to combine the broad spectrum Graphene Oxide (GO) materials together with Ag nanoparticles which can selectively adsorb polonium. First, the GO material with macro- and mesopores is assembled by hydrothermal method; then, the Ag nanoparticles are loaded in the GO matrix via radiation reduction; moreover, the GO-Ag multihollow material is combined with stainless steel mesh, and a novel GO-Ag-Stainless steel (GAS) filter with multilevel porous structure is obtained. The absorption ability of the GAS filter will be characterized on the self-designed heavy metal vapor filter test platform, meanwhile the Tellurium (Te) is utilized as the model element, which has the very similar physical and chemical properties as radioactive Po. In addition, the relation between the electrical properties and the adsorption capacity of the GAS composite filter is studied by the surface chemical and electrical chemical analysis, with the exploring on the adsorption mechanism. The results of this project not only deepens our understanding of gas atoms absorbing on GO, but also enriches surface adsorption theory on composite materials. Meanwhile, the GAS composite filter can provide theoretical guidance and experimental support for the structure design, material selection and life monitor of heavy metal vapor filter, which has broad application in the nuclear energy safety.

液态铅铋共晶合金作为加速器驱动次临界系统冷却剂的主选材料，在工作过程中会产生含钋放射性重金属蒸气，对铅基反应堆的安全造成潜在的危害。本申请项目拟利用氧化石墨烯（GO）的广谱吸附性能和金属银对钋的选择性吸附能力，通过水热法组装构建GO多孔材料，再通过辐射还原法将银纳米粒子负载于GO基体中，并与高强度不锈钢网复合，得到具有多级孔结构的氧化石墨烯-纳米银-不锈钢（GAS）复合滤材。进而在自主设计的重金属蒸气滤材检验平台上，以物化性质与放射性钋极其相似的碲作为模型原子，测定新型滤材对重金属蒸气的吸附性能。在此基础上，通过表面和电化学分析，获得GAS电学性能变化与饱和吸附量的关系，探索吸附机理。本项目的研究成果将加深人们对GO吸附气体原子机理的理解，丰富复合材料表面吸附理论，同时为放射性重金属蒸气滤材的结构设计、材料选择和在线监测提供理论指导和实验支持，在核安全领域具有广泛的应用前景。

液态铅铋共晶合金作为加速器驱动次临界系统冷却剂的主选材料，在工作过程中会产生放射性钋，对铅基反应堆的安全造成潜在的危害,因此需要设计选择一种具有对钋具有选择性吸附的材料。本项目已按计划与质量完成申请书中的既定研究目标，采用化学性质相似的同族元素碲代替放射性钋，选择载银不锈钢编织网和氧化石墨烯两种吸附载体，开展了Te(IV)的吸附行为及机理研究；在此基础上，以氧化石墨烯为前驱体，以抗坏血酸、亚硫酸氢钠及乙二胺为还原剂，构建纳米银/石墨烯水凝胶，并确定碲信号最强的乙二胺还原诱导自组合纳米银/石墨烯水凝胶为基底材料，开展了纳米银/石墨烯水凝胶对碲的吸附及利用表面增强拉曼散射技术对微量碲元素检测的研究工作，同时扩展研究了新型免超声无皂低缺陷石墨烯的制备方案。通过本项目研究，充分证明了银对碲的选择吸附性，制备的复合材料对碲吸附量大，且对微量Te(IV)的最低检出限可低至100 nM。项目发表SCI论文4篇，EI论文1篇，培养博士毕业生2名。项目负责人受本项目培养，已于2017年获批国家自然科学基金面上项目一项。