高选择性典型长寿期放射性核素吸附材料研究

The construction, testing, operation, maintenance, decommissioning of nuclear power plants and their nuclear accidents have been and are produced large amounts of radioactive waste water, which contain high levels of long-lived radioactive nuclides with a serious environmental hazard. Among various treatment schemes, efficient selective adsorption or ion exchange is a foreign research hot spot, especially the efficient treatment of a large quantity of radioactive waste water produced by serious nuclear accidents is a world problem. The project is based on the relative research at home and abroad, combined with the accumulation of the research work of the research group in recent years. Resin-like composite adsorption materials were synthesized by supporting high selective inorganic adsorption materials, modified chitin on polymer carriers, and were used to the adsorption of the typical long-lived radioactive nuclides, such as Cs-137, Sr-90 and Co-60, Fe-59, Mn-54. Structural adjustment of the adsorption materials can be conducted via changing the types of polymer carriers, changing loading conditions, the introduction of special groups and the closing of carboxyl groups towards chitin. The physicochemical behavior of the adsorption materials will be specified with different techniques including scanning election microscopy (SEM), Fourier Transform Infrared Spectroscopy (FT-IR), specific surface analysis, batch experiments and column experiments, in order to explore the relationship between the structure of the adsorption materials and their adsorption properties of the above nuclides. Furthermore, the synthesization of the adsorption materials will provide the theoretical basis for optimization of the design of high-performance adsorption materials, and will lay an important foundation for the development of related materials.

核动力装置建造、试验、运行、维护、退役过程中及事故时会产生大量的放射性废水，对其所含的含量高、环境危害大的长寿期放射性核素采取高效选择性吸附或离子交换是目前国外研究的热点问题，特别是严重核事故时大量放射性污水的高效处理是世界性的难题。本项目基于国内外相关研究的基础，结合课题组近年研究工作的积累，利用聚合物载体负载选择性无机吸附材料、改性甲壳素合成得到类树脂状复合吸附材料，分别吸附废水中典型的长寿期核素：Cs-137、Sr-90及Co-60、Fe-59和Mn-54等。通过改变聚合物载体的种类、负载条件、在甲壳素上引入特定基团及对羧基进行封闭等措施调整吸附材料的结构，采用SEM、FT-IR、比表面积测试、静态吸附、动态吸附测试等方法测定其物理化学性能，探索吸附材料的结构与吸附材料对上述核素吸附性能之间的关系，为将来高性能选择性吸附材料的优化设计提供理论依据，为相关材料的开发奠定重要的基础。

核设施在日常运行、维修、退役等环节会产生大量含典型长寿期核素137Cs、90Sr、60Co和54Mn等的放射性废水，对环境及人类健康产生严重威胁。为选择性去除放射性废水中的典型长寿期核素并达到放射性废物最小化的要求，开发了多种类型的铯、锶选择性吸附剂及钴、锰等活化产物吸附剂的制备，优化了吸附剂制备工艺，研究了其结构及其对目标离子的吸附性能。. 以聚丙烯腈（PAN）、交联壳聚糖（CTS）、交联海藻酸（ALG）为基体，以合成的亚铁氰化钴钾（KCoCF）、亚铁氰化钛钾（KTiCF）和亚铁氰化镍钾（KNiCF）、钛硅酸钠（NaTS）、钛酸钾（KTiO）和层状金属硫化物等无机离子交换剂为活性成分，制备了多种铯、锶选择性吸附剂的制备，经研究，确定了PAN-KNiCF为对Cs+综合吸附性能最好的吸附剂，并且其对实际放射性废水中137Cs的表现出优异的选择性，而层状金属硫化物对Sr2+的选择性最为突出。以壳聚糖粉末、半胱氨酸、谷氨酸、天冬氨酸、赖氨酸、精氨酸和组氨酸为原料，采用离子印迹技术、溶胶—凝胶法与反相悬浮法结合制备了多种氨基酸接枝的钴/锰离子双印迹球型壳聚糖吸附剂，经研究，确定了天冬氨酸接枝的钴/锰双印迹交联壳聚糖吸附剂（Asp-Co/Mn-CCTS-2）为对Co2+和Mn2+综合吸附性能最好的吸附剂。. 本项目得到了多种具有自主知识产权的高选择性典型长寿期放射性核素吸附材料及其制备工艺，为高选择性典型长寿期放射性核素吸附材料的工程应用奠定了技术基础。