【作者】 杨晓；

【导师】 肖成梁； 徐超；

【作者基本信息】 浙江大学 ， 工程硕士（专业学位）， 2022， 硕士

【摘要】 我国已经提出了“双碳”政策,但国民经济的增长离不开能源的消耗。目前急需一种清洁能源以适应经济的飞速发展。核能是一种安全稳定的低碳能源,正好满足这一需求。我国已经着力于核能闭式循环体系的构建以安全有效地回收与处置在核能利用过程中产生的乏燃料。“分离-嬗变”策略是处理高放废液中长寿命核素最有效的技术手段。其中三价镧锕元素的分离是提高嬗变效率的关键。本课题设计合成了三类具有刚性结构的软硬结合邻菲罗啉类配体(N,N-二乙基-N,N 二甲基-1,10-邻菲罗啉-2,9-二酰胺(Et-Ph-DAPhen)、2,9-二乙基苯基磷氧基-1,10-邻菲罗啉(Et-Ph-BPPhen)和二乙基(1,10邻菲罗啉-2,9)二苯基次磷酸酯(Et-Ph-PIPhen),研究了其对三价镧锕离子的萃取与络合性能。结果如下:(1)酰胺类配体(Et-Ph-DAPhen)对Am(Ⅲ)具有十分显著的分离效果,但是萃取效果不好,并且与La(Ⅲ)和Eu(Ⅲ)均形成配体/Ln(Ⅲ)比为2:1和1:1两种络合物,而与Lu(Ⅲ)则只形成1:1的络合物。Et-Ph-DAPhen的logβ值随着镧系收缩逐渐变小,与Eu(Ⅲ)络合呈现出荧光淬灭效应,与La(NO3)3、Eu(NO3)3和Lu(NO3)3分别形成了 2:1与1:1、1:1和1:1的单晶结构。(2)有相同侧基的氧化膦类配体(Et-Ph-BPPhen)萃取效果十分显著,但是对Am(Ⅲ)和Eu(Ⅲ)几乎没有分离能力,并且与La(Ⅲ)只形成1:1的络合物,而与Lu(Ⅲ)和Eu(Ⅲ)均形成配体/Ln(Ⅲ)比为2:1和1:1两种络合物。Et-Ph-BPPhen的logβ值随着镧系收缩逐渐变增大,与Eu(Ⅲ)络合呈现出荧光增强效应,与La(NO3)3、Eu(NO3)3和 Lu(NO3)3都形成了 1:1 的单晶结构。(3)引入酯基O后得到的Et-Ph-PIPhen的萃取效果进一步提高,并且分离性能得到改善,其络合物种的形成趋势、logβ值随镧系收缩变化的规律和荧光效应同Et-Ph-BPPhen类似,并且与La(NO3)3和Eu(NO3)3形成了 1:1的单晶结构。三种配体的配位腔均随着镧系收缩而减小并且Eu-OL的平均键长结果与萃取结果和Eu(Ⅲ)的一级logβ值保持一致。本课题在侧基相同的情况下系统地比较了三类配体的萃取络合性质并且验证了对软硬结合邻菲罗啉配体上O供体原子电子云密度调控的可行性。更多还原

【Abstract】 Although the carbon reduction policy has been proposed in China,the growth of the national economy is closely related to the consumption of energy.Currently,a energy with low carbon emission is urgently demanded to meet the rapid economic development.Nuclear energy,a safe,stable and low-carbon energy,is quiet suitable for this need.The construction of a closed-loop nuclear energy cycle system has been implemented to recover and dispose of the spent nuclear fuel safely and effectively.The’Partitioning&Transmutation’ strategy is the most effective technique to dispose the long-periodic radioactive nuclides in high-level radioactive waste.In this process,the separation of trivalent lanthanides and actinides plays key roles to ensure the transmutation efficiency.In this project,we designed and synthesized three types of preorganized N,O-hybrid phenanthroline ligands,N,N-diethyl-N,N-dimethyl-1,10phenanthroline-2,9-diamide(Et-Ph-DAPhen),2,9-diethylphenylphosphoryl-1,10phenanthroline(Et-Ph-BPPhen)and diethyl((1,10-phenanthroline)-2,9-diyl)diphenyl hypophosphite(Et-Ph-PIPhen).The extraction and complexation properties of them with trivalent lanthanides and actinides were investigated.The relevant results are as followed:(1)The amide ligand(Et-Ph-DAPhen)had a very significant separation ability to Am(Ⅲ)but the extraction property was not well.And two complexes with the ligand/Ln(Ⅲ)ratio of 2:1 and 1:1 were formed in the complexation of Et-Ph-DAPhen with both La(Ⅲ)and Eu(Ⅲ),while only 1:1 complex of Et-Ph-DAPhen with Lu(Ⅲ)was formed.The log β values of Et-Ph-DAPhen decreased gradually with the lanthanide contraction and a fluorescence quenching effect was shown in the titration of Eu(Ⅲ)with Et-Ph-DAPhen.The single-crystal structures with Ligand/La(NO3)3 of 2:1 and 1:1,Ligand/Eu(NO3)3 of 1:1 and Ligand/Lu(NO3)3 of 1:1 were obtained.(2)The extraction ability of phosphine oxide ligands(Et-Ph-BPPhen)was great but this ligand had almost no separation ability of Am(Ⅲ)towards Eu(Ⅲ).Only 1:1 complex was formed when complexing with La(Ⅲ),while two complexes with ligand/Ln(Ⅲ)ratios of 2:1 and 1:1 were formed in complexation of Et-Ph-BPPhen with both Lu(Ⅲ)and Eu(Ⅲ).The log β values of Et-Ph-BPPhen gradually increased with the lanthanide contraction and a fluorescence enhancement effect was shown in the titration of Eu(Ⅲ)with Et-Ph-BPPhen.1:1 single-crystal structures of Et-Ph-BPPhen with all La(NO3)3,Eu(NO3)3 and Lu(NO3)3 were cultivated.(3)The extraction ability of Et-Ph-PIPhen obtained by inserting ester O atoms to Et-Ph-BPPhen was further improved,and the separation performance was also increased.The formation trend of complex species,the change of log β values with lanthanide contraction and the fluorescence effect of Et-Ph-PIPhen was found.1:1 single-crystal structures of Et-Ph-PIPhen with both La(NO3)3 and Eu(NO3)3 were acquired.The coordination cavities of the three ligands decreased with the lanthanide contraction and the average bond lengths of Eu-OL were consistent with the extraction results and the first-order log β values of Eu(Ⅲ).In this study,the extraction and complexation properties of the three types of ligands with the same substituent groups were systematacially compared and the feasibility of modifying the electron density of O donor atoms on the N,O-hybrid phenanthroline ligands was verified.更多还原