离子液体萃取锝和铼的研究

系统地研究离子液体对ReO_4~-和TcO_4~-的萃取。结果发现,咪唑类和季铵盐类离子液体可通过阴离子交换机理高效萃取ReO_4~-和TcO_4~-。其中,PF_6~-类离子液体对ReO_4~-和TcO_4~-的萃取效率明显高于NTf_2~-类离子液体。当阴离子相同时,离子液体阳离子侧链增长,萃取效率增大。增加水相HNO_3浓度或在水相中加入相应离子液体的阴离子可以抑制ReO_4~-和TcO_4~-的萃取。水相中加入相应离子液体的阳离子则可以促进萃取反应进行。在低酸度下,己基三丁基铵双三氟甲烷磺酰亚胺N_(6,444)]NTf2]和1-辛基-3-甲基咪唑六氟磷酸盐C_8mim]PF_6]对模拟废液中的ReO_4~-均具有很好的萃取选择性。LiNTf_2和KPF_6水溶液可以分别实现对N_(6,444)]NTf_2]和C_8mim]PF6]中ReO_4~-的有效反萃。

Extraction of Technetium and Rhenium with Ionic Liquid

The extraction of ReO4? and TcO4? by ionic liquids (ILs) were investigated systematically. The results indicated that imidazolium and quaternary ammonium ILs could extract ReO4? and TcO4? efficiently via anion-exchange mechanism. Compared with NTf2-based ILs, PF6-based ILs had a higher extraction efficiency towards ReO4? and TcO4?. With respect to the ILs with an identical anion, the extraction efficiency increased with the increase of the chain length of IL's cations. The addition of HNO3 and IL's anion in aqueous phase decreased the extraction efficiency, while the increase of the concentration of IL's cation led to an opposite effect. At a lower concentration of nitric acid, ReO4? ions were selectively extracted by either N6,444]NTf2] or C8mim]PF6] from simulated liquid waste. KPF6 and LiNTf2 aqueous solutions can strip ReO4? effectively from C8mim]PF6] and N6,444]NTf2], respectively.