Extraction of Technetium and Rhenium with Ionic Liquid

doi:10.13209/j.0479-8023.2017.074

Abstract

Abstract:

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 [N_6,444][NTf₂] or [C₈mim][PF₆] from simulated liquid waste. KPF₆and LiNTf₂aqueous solutions can strip ReO₄^- effectively from [C₈mim][PF₆] and [N_6,444][NTf₂], respectively.

Key words: ionic liquid, ReO₄^-, TcO₄^-, extraction selectivity, extraction mechanism

摘要：

系统地研究离子液体对ReO₄^-和TcO₄^-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ReO₄^-和TcO₄^-。其中, PF₆^-类离子液体对ReO₄^-和TcO₄^-的萃取效率明显高于NTf₂^-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HNO₃浓度或在水相中加入相应离子液体的阴离子可以抑制ReO₄^-和TcO₄^-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[C₈mim][PF₆]对模拟废液中的ReO₄^-均具有很好的萃取选择性。LiNTf₂和KPF₆水溶液可以分别实现对[N_6,444][NTf₂]和[C₈mim][PF₆]中ReO₄^-的有效反萃。

关键词: 离子液体, ReO₄^-, TcO₄^-, 萃取选择性, 萃取机理

Yue SONG, Taoxiang SUN, Qingde CHEN, Xinghai SHEN. Extraction of Technetium and Rhenium with Ionic Liquid[J]. Acta Scientiarum Naturalium Universitatis Pekinensis, 2017, 53(5): 810-816.

宋岳, 孙涛祥, 陈庆德, 沈兴海. 离子液体萃取锝和铼的研究[J]. 北京大学学报自然科学版, 2017, 53(5): 810-816.

Figures/Tables 8

Table 1 Compositions of simulated liquid waste (SLW)[19]

元素	浓度/(g ∙ L^-1)	元素	浓度/(g ∙ L^-1)
Sr	0.54	Ru	0.38
Cs	0.54	Ni	0.17
Zr	0.68	Nd	1.00
Cr	0.34	U	2.38
Re	0.15

Fig. 1 Extraction efficiencies of 0.01 mol/L ReO4- and tracer amount of TcO4- using different ILs

Fig. 2 Effect of HNO3 (solid) and LiNO3 (hollow) on the extraction of 0.01 mol/L ReO4- (▲ and △) and tracer amount of TcO4- (▼) by [N6,444][NTf2], and on the extraction of 0.01 mol/L ReO4- (■ and □), tracer amount of TcO4- (●) by [C8mim][PF6]

Fig. 3 Effects of [N6,444]Cl (■) and LiNTf2 (●) on the extraction of 0.01 mol/L ReO4- by [N6,444][NTf2], and effects of [C8mim]Cl (▲) and KPF6 (▼) on the extraction of 0.01 mol/L ReO4- by [C8mim][PF6]

Fig. 4 ESI-MS spectra of IL phase after extracting0.1 mol/L ReO4- by [C8mim][PF6]

Table 2 Peak positions associated in the ESI-MS spectra of IL phase after extracting 0.1 mol/L ReO4- with [C8mim][PF6]

模式	峰的归属	m/z
阴离子谱	[3C₈mim⁺+3PF₆^-+ReO₄^-]^-	1271.3
	[3C₈mim⁺+4PF₆^-]^-	1165.4
	[2C₈mim⁺+2PF₆^-+ReO₄^-]^-	931.2
	[2C₈mim⁺+3PF₆^-]^-	825.2
	[C₈mim⁺+2PF₆^-]^-	485.1
	ReO₄^-	250.9
阳离子谱	[5C₈mim⁺+4PF₆^-]⁺	1555.8
	[2C₈mim⁺+PF₆^-]⁺	535.3
	C₈mim⁺	195.2

Fig. 5 Effects of HNO3 on the extraction of different elements in SLW by [C8mim][PF6] (a) and [N6,444][NTf2] (b), respectively

Fig. 6 Dependence of the total stripping efficiency of ReO4- in [N6,444][NTf2] (●) and [C8mim][PF6] (▲) on the number of stripping (the stripping agents were LiNTf2 and KPF6 aqueous solutions, respectively)

References 24

[1]	Katayev E A, Kolesnikov G V, Sessler J L. Molecular recognition of pertechnetate and perrhenate.Chemi- cal Society Reviews, 2009, 38(6):1572-1586
[2]	Schurhammer R, Wipff G. Liquid-liquid extraction of pertechnetic add (Tc-Ⅶ) by tri-n-butyl phosphate: where is the proton? A molecular dynamics investi-gation.Journal of Physical Chemistry B, 2011, 115(10):2338-2348
[3]	冯孝贵, 梁俊福, 宋崇立, 等. 硝酸体系中三烷基氧膦萃取Tc(Ⅶ)的研究.核化学与放射化学, 1998, 20(2):33-39
[4]	Jalhoom M G. Extraction of technetium by crown ethers and cryptands.Journal of Radioanalytical and Nuclear Chemistry-Letters, 1986, 104(3):131-140
[5]	Kuzina A F, German K E, Spitsyn V I. Obtaining metal rhenium by thermal-decomposition of tetraal-kylammonium perrhenate.Doklady Akademii Nauk Sssr, 1987, 297(2):380-381
[6]	Kopunec R, Abudeab F N, Skraskova S. Extraction of pertechnetate with tetraphenylphosphonium in the presence of various acids, salts and hydroxides.Journal of Radioanalytical and Nuclear Chemistry, 1998, 230(1/2):51-60
[7]	Omori T, Muraoka Y, Suganuma H. Solvent-extraction mechanism of pertecnetate with tetraphenylarsonium chloride. Journal of Radioanalytical and Nuclear Chemistry, 1994, 178(2):237-243
[8]	Mausolf E, Droessler J, Poineau F, et al. Tetraphe-nylpyridinium pertechnetate: a promising salt for the immobilization of technetium.Radiochimica Acta, 2012, 100(5):325-328
[9]	Ali M C, Suzuki T, Tachibana Y, et al. Selective extraction of perrhenate anion in nitric acid solution using 2,2′-(imino)bis(N,N′-dioctylacetamide) as an extractant.Separation and Purification Technology, 2012, 92:77-82
[10]	Saeki M, Sasaki Y, Nakai A, et al.Structural study on 2,2'-(methylimino)bis(N,N-dioctylacetamide) complex with Re(Ⅶ)O4- and Tc(Ⅶ)O4- by 1H NMR, EXAFS, and IR spectroscopy.Inorganic Chemistry, 2012, 51 (10):5814-5821
[11]	Bonhote P, Dias A P, Papageorgiou N, et al. Hy-drophobic, highly conductive ambient-temperature molten salts.Inorganic Chemistry, 1996, 35(5):1168- 1178
[12]	Dietz M L, Dzielawa J A.Ion-exchange as a mode of cation transfer into room-temperature ionic liquids containing crown ethers: implications for the “green- ness” of ionic liquids as diluents in liquid-liquid extraction. Chemical Communications, 2001, 20: 2124‒2125
[13]	Jensen M P, Dzielawa J A, Rickert P, et al. EXAFS investigations of the mechanism of facilitated ion transfer into a room-temperature ionic liquid.Journal of the American Chemical Society, 2002, 124(36):10664-10665
[14]	Jensen M P, Neuefeind J, Beitz J V, et al. Mecha-nisms of metal ion transfer into room-temperature ionic liquids: the role of anion exchange.Journal of the American Chemical Society, 2003, 125(50):15466- 15473
[15]	刘海望, 杨涛, 陈庆德, 等离子液体体系的萃取行为及其在乏燃料后处理中的应用前景.核化学与放射化学, 2015, 37(5):286-309
[16]	Fu J, Chen Q D, Sun T X, et al. Extraction of Th(Ⅳ) from aqueous solution by room-temperature ionic liquids and coupled with supercritical carbon dioxide stripping.Separation and Purification Technology, 2013, 119:66-71
[17]	Fu J, Chen Q D, Shen X H. Stripping of uranium from an ionic liquid medium by TOPO-modified super-critical carbon dioxide.Science China Chemistry, 2014, 58(3):545-550
[18]	Xu C, Yuan L Y, Shen X H, et al. Efficient removal of caesium ions from aqueous solution using a calix crown ether in ionic liquids: mechanism and radia- tion effect.Dalton Transactions, 2010, 39(16):3897- 3902
[19]	刘海望, 沈兴海, 陈庆德. 三丁基氧化膦‒离子液体体系萃取UO2(NO3)2的机理和选择性.物理化学学报, 2015, 31(5):843-851
[20]	Chun S, Dzyuba S V, Bartsch R A. Influence of structural variation in room-temperature ionic liquids on the selectivity and efficiency of competitive alkali metal salt extraction by a crown ether. Analytical Chemistry, 2001, 73(15):3737-3741
[21]	Zuo Y, Liu Y, Chen J, et al. The separation of Cerium(Ⅳ) from nitric acid solutions containing Thorium(Ⅳ) andLanthanides(Ⅲ) using pure C8mimPF6 as extracting phase.Industrial & Engineering Chemis-try Research, 2008, 47(7):2349-2355
[22]	Stepinski D C, Vandegrift G F, Shkrob I A, et al. Extraction of tetra-oxo anions into a hydrophobic, ionic liquid-based solvent without concomitant ion exchange.Industrial & Engineering Chemistry Re- search, 2010, 49(12):5863-5868
[23]	Yang J, Kubota F, Baba Y. Separation of precious metals by using undiluted ionic liquids.Solvent Ex-traction Research and Development, 2014, 21(1):89- 94
[24]	Pathak P N, Prabhu D R, Kumari N, et al. Studies on the extraction of actinides using a solvent containing D2EHiBA in room temperature ionic liquids: Unu- sual extraction of the tetravalent ions.Separation Science and Technology, 2015, 50(3):373-379