Study on the extraction of lanthanides by isomeric diglycolamide extractants: an experimental and theoretical study

Yaoyang Liu; Chuang Zhao; Zhibin Liu; Sheng Liu; Yu Zhou; Caishan Jiao; Meng Zhang; Yang Gao; Hui He; Shaowen Zhang

doi:10.1039/d1ra07020g

Study on the extraction of lanthanides by isomeric diglycolamide extractants: an experimental and theoretical study

RSC Adv. 2021 Dec 24;12(2):790-797. doi: 10.1039/d1ra07020g. eCollection 2021 Dec 22.

Authors

Yaoyang Liu¹, Chuang Zhao¹, Zhibin Liu¹, Sheng Liu¹, Yu Zhou¹, Caishan Jiao¹, Meng Zhang¹, Yang Gao¹, Hui He^{1

2}, Shaowen Zhang³

Affiliations

¹ Fundamental Science on Nuclear Safety and Simulation Technology Laboratory, College of Nuclear Science and Technology, Harbin Engineering University Harbin 150001 Heilongjiang Province China gaoyang@hrbeu.edu.cn.
² China Institute of Atomic Energy P. O. Box 275 (126) Beijing 102413 China hehui@ciae.ac.cn.
³ School of Chemistry and Chemical Engineering, Key Laboratory of Cluster Science of Ministry of Education, Beijing Institute of Technology Beijing 100081 China.

Abstract

Two isomeric diglycolamide (DGA) extractants, N,N'-dimethyl-N,N'-dioctyl diglycolamide (L^I) and N,N-dimethyl-N',N'-dioctyl diglycolamide (L^II), were used to perform a comparative study on the extraction performances towards several lanthanides by extraction experiments and theoretical calculations. The experimental results show that both L^I and L^II show a positive sequence on the extraction of lanthanides, and L^I exhibits the higher complex ability with these lanthanides than L^II, except for La and Ce. Slope analysis shows that 1:2 or 1:3 complexes are formed between the two ligands and the metal ions. The geometrical structures of the complexes were optimized in the gas phase by density functional theory (DFT) on the basis of complex compositions. The results of bond lengths, MBOs and topological analysis indicated that the electrostatic interaction between metal ions and two amide O atoms in the L^II ligand is not as homogeneous as in L^I, and this inhomogeneity is likely to be related to the poor extraction performance of L^II.