A DGA-arm-grafted macrocyclic aza-crown ether ligand (Cr6DGA) was synthesized, and its solvent extraction behavior toward trivalent americium and europium in nitric acid medium was studied. The effects of various parameters such as the contact time, temperature, concentration of the extractant, and acidity on the extraction by Cr6DGA were investigated. It was found that in 3 mol/L HNO3, the SFEu/Am value was about 2. The complexation energies calculated by DFT showed that the Eu(III) complexes were more stable than the corresponding Am(III) complexes in gas, aqueous, and organic phases. Furthermore, the coordination study showed that the metal/ligand ratio of the extracted species was 1:2 by mass spectrometry (MS) analysis. The time-resolved laser-induced fluorescence spectra (TRLFS) further proved that the extracted species contained one water molecule, and so the composition of the extracted complexes may be [EuL2NO3(H2O)]2+ or [EuL2(NO3)2(H2O)]+. Finally, DFT calculations revealed that [EuL2(NO3)2(H2O)]+ is a more stable species and the binding energy of Eu(III) with the DGA unit is lower than that with the crown unit.
Diglycolamide (DGA) extractants, especially TODGA ( N , N , N′ , N′ ‐tetraoctyl diglycolamide), show significant potential in high-level liquid waste treatment. However, their limited loading capacity for trivalent lanthanides (Lns) and actinides (Ans) often leads to detrimental emulsification or third phase formation, hindering their practical applicability. Herein, TOOEDGA ( N , N , N’ , N’ -tetra(2-(octyloxy)ethyl)diglycolamide), a new DGA extractant with long C-chains combined with ether bonds, exhibits superior extraction performance towards Am 3+ and Eu 3+ in HNO 3 solution compared to TODGA. The factors influencing the formation of a third phase during the extraction process were investigated. It has been shown that TOOEDGA has a greater loading capacity for Lns 3+ and can tolerate a wider concentration range of HNO 3 . Additionally, the aggregation behavior of DGAs in n -dodecane was also studied using dynamic light scattering and small-angle X-ray scattering, revealing that the reverse micelles formed by TOOEDGA are more stable than those formed by TODGA. Moreover, under similar conditions, TOOEDGA molecules do not aggregate further to generate rod-like reverse micelle aggregates like those observed with TODGA, which is beneficial to inhibit the formation of the third phase. Consequently, our results suggest that TOOEDGA holds great promise as an alternative DGA extractant for practical industrial applications.
危险品化学品经营许可证（带存储）