铌钽掺杂六方相氧化钨对锶铯的吸附性能研究

项目名称： 铌钽掺杂六方相氧化钨对锶铯的吸附性能研究

项目编号： No.21501159

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 化学工程及工业化学

项目作者： 牟婉君

作者单位： 中国工程物理研究院核物理与化学研究所

项目金额： 20万元

中文摘要： 六方钨青铜结构的氧化钨沿着c 轴方向存在六元环孔道，孔道中容纳的客体离子能被其它离子交换，可以用作吸附剂处理酸性放射性废液。前期研究中发现铌或钽掺杂能明显提高六方氧化钨对Sr2+和Cs+的离子吸附能力，采用该材料能同时将90Sr 和137Cs 从强酸性放射性废液中分离出来，简化放射性废液的后续处理流程，降低二次废液的产生量。拟继续开展材料的合成方法研究,通过结构解析研究铌、钽掺杂对六方氧化钨微观结构的影响。采用离子吸附实验、滴定实验研究离子吸附过程。采用谱学测试分析考察Sr2+和Cs+进入氧化钨骨架孔道后发生的主客体作用。通过以上实验与理论数值模拟相结合的方法，分析材料本体结构与不同客体离子之间固相键合能力的差异，阐明铌、钽掺杂对材料吸附Sr2+和Cs+性能的影响机理。研究结果可望为放射性废液中90Sr 和137Cs 吸附材料的结构设计与材料合成提供理论

中文关键词： 裂变产物；离子交换；微观结构

英文摘要： The fission products 90Sr and 137Cs are very important in addressing waste disposal issues because they generate large amounts of heat for the first several hundredyears. Heat generation in the repository is an issue because heat combined with slight moisture from the surrounding rock could accelerate corrosion of the waste canisters if it comes into contact with them. To avoid this, 90Sr and 137Cs must be separated from other radioactive fission products. Tungsten oxide with hexagonal tungsten bronze structure (hex-WO3) has attracted much attention owing to its well known tunnel structure. Guest ions in the “hexagonal window” tunnels of the hex-WO3 can be exchanged by Cs+, Sr2+ and other ions. We have found that adsorption amount of Sr2+ and Cs+ onto hex-WO3 can be improved by isomorphous incorporation of Tantalun or Niobium ions. The Tantalun or Niobium doped hex-WO3 is very robust in acidic solution and may be used as adsorbents to separate 90Sr and 137Cs from fission waste. The bulk of radioactive effluent can be disposed as low-level waste with concomitant cost savings if the strategy that to pretreat 90Sr and 137Cs by a small volume of sorbent is achieved. The aim of the proposal is to study chemical and charge imbalance of hex-WO3 induced by isomorphic substitution of Tantalum or Niobium ions if there is any local change and to elucidate the nature of the Cs+ and Sr2+ siting in the Tantalum or Niobium doped hex-WO3 when Cs+ and Sr2+ ions are captured and immobilised in hexagonal tunnels after adsorption process is carried out. To understand the adsorption behavior as a function of Tantalum or Niobium doped hex-WO3, particularly how framework composition may be tailed for optimum ion adsorption behavior, the host-gust chemistry interaction between Tantalum or Niobium doped hex-WO3 noumenal framework and extraframework Sr2+ and Cs+ cations also will be detailed performed. The results of this project will reveal the structural basis of selectivity for Cs+ and Sr2+ of Tantalum or Niobium doped hex-WO3 and could avail to design and develop new efficient and selective sorbents for the treatment of 90Sr and 137Cs waste effluents.

英文关键词： fission product;ion exchange; microstructure