Effect of radiolysis of TODGA on the extraction of TODGA/n-dodecane toward Eu(Ⅲ):an experimental and DFT study  

作　　者：Hang Zhang Yin-Yong Ao Yue Wang Shang-Jie Zhao Jia-Yang Sun Mao-Lin Zhai Jiu-Qiang Li Jing Peng Hui-Bo Li 

机构地区：[1]Department of Radiochemistry,China Institute of Atomic Energy,Beijing 102413,China [2]Beijing National Laboratory for Molecular Sciences,Radiochemistry and Radiation Chemistry Key Laboratory for Fundamental Science,College of Chemistry and Molecular Engineering,Peking University,Beijing 100871,China [3]Institute of Nuclear Physics and Chemistry,China Academy of Engineering Physics,Mianyang 621900,China

出　　处：《Nuclear Science and Techniques》2023年第4期1-13,共13页核技术（英文）

摘　　要：N,N,N′,N′-Tetraoctyl diglycolamide(TODGA)is one of the most promising extractants tailored for high-level liquid radioactive waste treatment during nuclear fuel reprocessing.Theγ-radiolysis of TODGA(0.2 mol/L)in n-dodecane(n DD)solution with and without pre-equilibrated 3.0 mol/L HNO_(3)was investigated using HPLC and UPLC-QTOF-MS and compared with theγ-radiolysis of neat TODGA in this study.With increased absorbed doses,the concentration of TODGA decreased exponentially for the studied systems.Moreover,pre-equilibration with HNO_(3)(3.0 mol/L)slightly influenced theγ-radiolysis of TODGA in n DD.Seven radiolytic products generated from the rupture of the C–C,C–O,and C–N bonds in TODGA were identified in the studied extraction system.The influence ofγ-radiation on TODGA/n DD for the extraction of Eu(Ⅲ)was evaluated using the first combination of extraction experiments and density functional theory(DFT)calculations,in which the complexations of Eu(Ⅲ)with TODGA and its radiolytic products were systematically compared.Based on the radiolysis kinetic model of TODGA,the slope curve of the distribution ratio of Eu(Ⅲ)(D_(Eu))and the absorbed dose,and fluorescence titration analysis,the empirical equation of the absorbed dose and D_(Eu)was obtained successfully.Below 300 kGy,the experimental D_(Eu)agreed well with the obtained empirical equation for TODGA/n DD.Conversely,at a high absorbed dose,the experimental D_(Eu)was higher than the theoretical D_(Eu)based on the empirical equation because the radiolytic products of TODGA with similar coordination structures still possessed partial complexation toward Eu(Ⅲ),which was confirmed by DFT calculations.This work provides a method to predict the extraction distribution ratio of an irradiated extractant system and to understand the complex extraction process.

关 键 词：TODGA Radiolytic products EXTRACTION Density functional theory COMPLEXATION 

分 类 号：TL24[核科学技术—核燃料循环与材料] TQ028.32[化学工程]