【作者】 张鹏；

【导师】 史克亮；

【作者基本信息】 兰州大学 ， 化学·放射化学， 2020， 硕士

【摘要】 核能作为一种清洁能源,在我国能源布局中具有潜在的发展优势。在核能的应用过程中,因人为或自然原因,部分放射性核素被释放到环境中,引起一定的放射性污染,其中包括铀和超铀元素。它们半衰期长,化学毒性大,在环境安全评价、核废物地质处置以及生物效应等方面备受关注。土壤及水体是联系生物圈的主要媒介,开展对环境土壤及水体中铀和超铀元素的快速、准确测定,是环境监测和放射性核素安全评价的重要手段。环境样品基体复杂,铀和超铀元素含量低,需要经过预处理及化学分离纯化,进而建立相应的分析流程。本文根据样品基体特性选取相应的预处理方法,通过固相萃取树脂进行分离纯化,采用HR-ICP-MS测量目标元素含量,最终建立了环境土壤样品中铀的分析流程。同时研究了将Eu作为Am分析过程中示踪剂的可行性,结果表明在共沉淀及柱分离过程,Am和Eu的化学行为基本一致,最终将¹⁵³Eu作为示踪剂建立了环境水样中²⁴¹Am的分析流程。此外,针对质谱测量过程中²³⁸U对²³⁷Np的干扰,采用固相萃取法实现了U/Np的分离,为后续样品中锕系元素的同时分离分析奠定了基础。更多还原

【Abstract】 As a kind of clean energy,nuclear energy has potential advantages in China’s energy distribution.During the application of nuclear energy,due to man-made or natural reasons,some radionuclides are released into the environment,causing certain radioactive contamination.Because of the long half-lives,high chemical toxicity,uranium and transuranic elements are often attracted in environmental safety evaluation,geological disposal of nuclear waste and biological effects.Soil and water are important media in contact with the biosphere.Therefore,the rapid and accurate determination of uranium and transuranic elements in environmental soil and water samples is an important means of environmental monitoring and safety evaluation of radionuclides.The content of uranium and transuranic elements in the environmental samples is often low and the matrix is complex,it is necessary to go through pretreatment and chemical separation and purification to establish the corresponding analytical procedure.In this paper,appropriate pretreatment methods were selected according to the characteristics of the matrix,and solid-phase extraction chromatographic techniques was used for the target element separation and purification,and HR-ICP-MS was used for measurement.Accordingly,the analytical procedureof uranium in environmental soil samples was established.Meanwhile,the feasibility of using Eu as a tracer in Am analysis was evaluated.It is noticed that the chemical behaviors of Am and Eu is similar in the co-precipitation and column separation process.¹⁵³Eu was used as a tracer to establish the analytical procedure of ²⁴¹Am in environmental water samples.In addition,in view of the interference of ²³⁸U to ²³⁷Np in the mass spectrometry measurement,solid-phase extraction chromatographic was used to separate U and Np,which laid the foundation for the simultaneous separation analysis of actinium elements in subsequent samples.更多还原