Selective Extraction and Complexation Studies for Thorium(IV) with Bis-triamide Extractants: Synthesis, Solvent Extraction, EXAFS, and DFT
Selective Extraction and Complexation Studies for Thorium(IV) with Bis-triamide Extractants: Synthesis, Solvent Extraction, EXAFS, and DFT
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使用双三酰胺萃取剂对钍 (IV) 进行选择性萃取和络合研究：合成、溶剂萃取、EXAFS 和 DFT
DOI：
10.1021/acs.inorgchem.1c01660
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发表时间：
2021
影响因子：
4.6
通讯作者：
Xia C.
中科院分区：
文献类型：
--
作者：
Kang J.;Wu R.;Li L.;Hu H.;Fan Y.;Jin Y.;Huang C.;Chen J.;Xu C.;Xia C.
设计并合成了三种辛基扩链双三酰胺萃取剂（L1-L3），用于煤油-硝酸体系中Th（IV）对U（VI）的选择性萃取。L1和L2对Th（IV）对U（VI）有较好的萃取性能和选择性，在10 min内达到萃取平衡。L1和L2的Th（IV）/U（VI）分离因子（SFTh/U）分别为12.1 ± 1.6 ~ 123.0 ± 20.2和15.2 ± 2.4 ~ 88.1 ± 14.9。斜率分析表明，Th（IV）在不同HNO 3浓度下以不同的形态被萃取，在0.1、1.0和3.0M HNO 3条件下，L1的斜率分别为2.08 ± 0.20、1.61 ± 0.03和1.54 ± 0.03，L2的斜率分别为2.37 ± 0.22、2.07 ± 0.17和1.76 ± 0.18。连续变异法（Job plot）显示，在甲醇相中，配体/钍（L/Th）比为1.5：1，表明L1/L2和Th（IV）可形成1：1和2：1的L/Th混合萃取络合物。扩展X射线吸收精细结构（EXAFS）和密度泛函理论（DFT）计算表明，在0.1 M HNO 3溶液中，L1和L2与Th的萃合物为[2L 1·Th·3（NO3）]+和[2L 2·Th·3（NO3）]+。
Three octyl-extended bis-triamide extractants (L1–L3) were designed and synthesized for the selective solvent extraction of Th(IV) over U(VI) in a kerosene–HNO3system.L1andL2exhibited good extraction property and selectivity toward Th(IV) over U(VI) and reached extraction equilibrium within 10 min. In a wide range of a HNO3concentration from 0.1 to 3.0 M, the separation factor of Th(IV) over U(VI) (SFTh/U) ofL1andL2ranged from 12.1 ± 1.6 to 123.0 ± 20.2 and 15.2 ± 2.4 to 88.1 ± 14.9, respectively. Slope analysis indicated that Th(IV) was extracted as different species under different HNO3concentrations, in which the slopes were 2.08 ± 0.20, 1.61 ± 0.03, and 1.54 ± 0.03 forL1and 2.37 ± 0.22, 2.07 ± 0.17, and 1.76 ± 0.18 forL2under 0.1, 1.0, and 3.0 M HNO3, respectively. A continuous variation method (Job plot) illustrated a 1.5:1 ligand/thorium (L/Th) ratio in a methanol phase, indicating thatL1/L2and Th(IV) could form mixed 1:1 and 2:1 L/Th extracted complexes. Extended X-ray absorption fine structure (EXAFS) and density functional theory (DFT) calculations revealed that the extracted complexes ofL1andL2with Th during the extraction process at 0.1 M HNO3were [2L1·Th·3(NO3)]+and [2L2·Th·3(NO3)]+.