Experimental and theoretical studies on the extraction behavior of Cf(iii) by NTAamide(C8) ligand and the separation of Cf(iii)/Cm(iii)

Yi-Lin Wang; Feng-Feng Li; Zhe Xiao; Cong-Zhi Wang; Yang Liu; Wei-Qun Shi; Hui He

doi:10.1039/d2ra07660h

Experimental and theoretical studies on the extraction behavior of Cf(iii) by NTAamide(C8) ligand and the separation of Cf(iii)/Cm(iii)

RSC Adv. 2023 Jan 26;13(6):3781-3791. doi: 10.1039/d2ra07660h. eCollection 2023 Jan 24.

Authors

Yi-Lin Wang¹, Feng-Feng Li¹, Zhe Xiao¹, Cong-Zhi Wang², Yang Liu², Wei-Qun Shi², Hui He¹

Affiliations

¹ Department of Radiochemistry, China Institute of Atomic Energy Beijing 102413 P. R. China hehui401@126.com.
² Laboratory of Nuclear Energy Chemistry, Institute of High Energy Physics, Chinese Academy of Sciences Beijing 100049 P. R. China.

Abstract

In this work we studied the extraction behaviors of Cf(iii) by NTAamide (N,N,N',N',N'',N''-hexaocactyl-nitrilotriacetamide, C8) in nitric acid medium. Influencing factors such as contact time, concentration of NTAamide(C8), HNO₃ and NO₃ ^- as well as temperature were considered. The slope analysis showed that Cf(iii) should be coordinated in the form of neutral molecules, and the extraction complex should be Cf(NO₃)₃·2L (L = NTAamide(C8)), which can achieve better extraction effect under the low acidity condition. When the concentration of HNO₃ was 0.1 mol L^-1, the separation factor (SF_Cf/Cm) was 3.34. The extractant has application prospect to differentiate the trivalent Cf(iii) and Cm(iii) when the concentration of nitric acid is low. On the other hand, density functional theory (DFT) calculations were conducted to explore the coordination mechanism of NTAamide(C8) ligands with Cf/Cm cations. The NTAamide(C8) complexes of Cf(iii)/Cm(iii) have similar geometric structures, and An(iii) is more likely to form a complex with 1 : 2 stoichiometry (metal ion/ligands). In addition, bonding property and thermodynamics analyses showed that NTAamide(C8) ligands had stronger coordination ability with Cf(iii) over Cm(iii). Our work provides meaningful information with regard to the in-group separation of An(iii) in practical systems.