Comparison of uranyl extraction mechanisms in an ionic liquid by use of malonamide or malonamide-functionalized ionic liquid
作者:Marieke Bonnaffé-Moity、Ali Ouadi、Valérie Mazan、Stanislav Miroshnichenko、Dariia Ternova、Sylvia Georg、Michal Sypula、Clotilde Gaillard、Isabelle Billard
DOI:10.1039/c2dt12421a
日期:——
The extraction of uranyl from acidic (HNO3) aqueous solutions toward an ionic liquid phase, C1–C4–imTf2N (1-methyl,3-butylimidazolium Tf2N), has been investigated as a function of initial acid concentration and ligand concentration for two different extracting moieties: a classical malonamide, N,N′-dimethyl-N,N′-dibutylmalonamide (DMDBMA) and a functionalized IL composed of the Tf2N− anion and an imidazolium cation on which a malonamide pattern has been grafted (FIL-MA). The extraction mechanism, as demonstrated through the influence of added C1–C4–imCl or added LiTf2N in the aqueous phase, is slightly different between the DMDBMA and FIL-MA extracting agents. Modeling of the extraction data evidences a double extraction mechanism, with cation exchange of UO22+versus 2 H+ for DMDBMA or versus C1–C4 -im+ and H+ for FIL-MA at low acidic values, and through anion exchange of [UO2(NO3)3]−versus Tf2N− for both ligands at high HNO3 concentrations. The FIL-MA molecule is more efficient than its classical DMDBMA parent.
针对两种不同的萃取分子,研究了离子液体 C1-C4-imTf2N(1-甲基,3-丁基咪唑鎓 Tf2N)从酸性(HNO3)水溶液中萃取铀酰与初始酸浓度和配体浓度的函数关系:一种是传统的丙二酰胺,即 N,N′-二甲基-N,N′-二丁基丙二酰胺(DMDBMA),另一种是由 Tf2N- 阴离子和咪唑阳离子组成的功能化 IL,其上接枝了丙二酰胺图案(FIL-MA)。通过水相中添加的 C1-C4-imCl 或添加的 LiTf2N 的影响,可以看出 DMDBMA 和 FIL-MA 萃取剂的萃取机理略有不同。萃取数据模型证明了双重萃取机制:在低酸值条件下,DMDBMA 的阳离子交换为 UO22+ 对 2 H+,FIL-MA 的阳离子交换为 C1-C4-im+ 和 H+;在高浓度 HNO3 条件下,两种配体的阴离子交换为 [UO2(NO3)3]- 对 Tf2N-。FIL-MA 分子比传统的 DMDBMA 母体更有效。