γ-ray induced radiolysis of [C₂mim][NTf₂] and its effects on Dy³⁺ extraction

γ-ray induced radiolysis of [C 2 mim][NTf 2 ] and its effects on Dy 3+ extraction 1 equal first-author 2 equal 1 1 2 corresp Corresponding authors, ryuuchou@sjtu.edu.cn, mlzhai@pku.edu.cn Corresponding authors, ryuuchou@sjtu.edu.cn, mlzhai@pku.edu.cn ryuuchou@sjtu.edu.cn 2 Nuclear Chemical Engineering Laboratory, School of Nuclear Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China Nuclear Chemical Engineering Laboratory, School of Nuclear Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China Beijing National Laboratory for Molecular Sciences, Radiochemistry and Radiation Chemistry Key Laboratory for Fundamental Science, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China Beijing National Laboratory for Molecular Sciences, Radiochemistry and Radiation Chemistry Key Laboratory for Fundamental Science, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China The water-soluble radiolytic products of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide ionic liquid ([C 2 mim][NTf 2 ]) under γ-radiation, such as CF 3 SOOH, CF 3 SO 2 NH 2 , HF, and H 2 SO 3 , were identified by using 1 H NMR, 19 F NMR, and ion chromatography. The extraction behavior of Dy 3+ using irradiated [C 2 mim][NTf 2 ] in combination with 2,6-di(5,6-diisobutyl-1,2,4-triazin-3-yl)pyridine ( iso butyl-BTP) was studied and the abnormal increase of Dy 3+ partitioning after irradiation is mainly attributed to the precipitation formed between Dy 3+ and radiolytic products of [C 2 mim][NTf 2 ] (F - and SO 3 2- ). Washing irradiated [C 2 mim][NTf 2 ] with water provides a simple method for ionic liquid recycling. γ-Radiation [C 2 mim][NTf 2 ] Iso butyl-BTP Radiolytic product Dy 3+ extraction I. INTRODUCTION 1 Minor actinides-lanthanides (MA-Ln) separation is a huge challenge due to their similar chemical properties [ 1 1 - 3 3 1-3 ]. Bistriazinylpyridines (BTPs), such as heterocyclic nitrogen donor ligands, presents attractive selectivity for MA, compared to Ln that could make them excellent candidates for separating minor actinides [ 4 4 - 6 6 4-6 ]. Kolarik et al . reported that 2,6-bis(5,6-dipropyl-1,2,4-triazin-3-yl)pyridine in kerosene/2-etylhexanol extracted Am 3+ with a distribution ratio of 23 from an aqueous phase [ 7 7 ]. Trumm et al . reported that a solution of 50 mmol/L BTPs in kerosene/1-octanol extracted Am 3+ from 1 mmol/L HNO 3 with SF Am/Eu at ca. 100 [ 8 8 ]. However, the BTPs in combination with a traditional solvent caused a new problem relating to radiation resistance. For example, a solution of 0.005 mmol/L C5-BTBP in cyclohexanone exhibited about an 80% decrease in the distribution ratio of Am 3+ at 17 kGy [ 9 9 ]. It was also reported that an absorbed dose of 100 kGy resulted in 80% decomposition of BTPs in n -octanol [ 10 10 ]. It was thought that the reaction between BTPs and the radicals of diluents resulted in subsequent degradation, which was mainly responsible for the decrease in metal ion partitioning. Due to a number of unique properties, such as non-volatility, good solubility, and chemical stability [ 11 11 - 13 13 11-13 ], room temperature ionic liquids (RTILs) have been highly studied for their potential application in the reprocessing of spent nuclear fuel [ 14 14 - 17 17 14-17 ]. Dai et al . first reported that the solvation environment offered by RTILs could enhance the extraction efficiency of metal ions from an aqueous solution [ 18 18 ]. Moreover, RTILs have demonstrated a notable radiation resistance under γ-radiation [ 19 19 - 24 24 19-24 ]. Berthon et al . noted that less than 1% underwent radiolysis when RTILs were exposed to a dose of 1200 kGy [ 25 25 ]. The main radiolytic products of 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C 4 mim][NTf 2 ]) were identified definitely through various spectroscopic methods in our previous work, which greatly improved the radiolysis research on ionic liquids [ 26 26 , 27 27 ]. The overall concentration of non-volatile acidic radiolysis products was less than 1% for [C 4 mim][NTf 2 ], even at 500 kGy. However, [C 2 mim][NTf 2 ] was considered as a better solvent rather than [C 4 mim][NTf 2 ] in the separation of MA-Ln due to its larger dissolving capacity and its liquidity [ 28 28 , 29 29 ]. Accordingly, it is necessary to access the radiation stability of [C 2 mim][NTf 2 ] and extraction ability of extractant in combination with [C 2 mim][NTf 2 ] under γ-radiation. In this paper, an extraction system consisted of iso butyl-BTP ( Fig. 1 Fig. 1 ) as extractant and [C 2 mim][NTf 2 ] as diluents is designed in our lab. The radiation effect on extraction behavior of the diluent [C 2 mim][NTf 2 ] is mainly investigated. Dy 3+ is a non-redox-active trivalent ion and has similar properties to the trivalent actinides, thus Dy 3+ is chosen for assessing the extractability and the radiation stability of the iso butyl-BTP/[C 2 mim][NTf 2 ] system. II. EXPERIMENTAL SECTION 1 A. Materials 2 [C 2 mim][NTf 2 ] (with a purity > 99%) was purchased from Lanzhou Greenchem ILs, LICP, CAS, China (Lanzhou, China). No impurities were detected by 1 H NMR spectrometry. The iso butyl-BTP( > 95%) was synthesized according to [ 30 30 ]. All other solvents were analytical-grade reagent and used without further purification. B. Irradiation 2 The irradiation of [C 2 mim][NTf 2 ] was carried out in air (298 (4) K) using a 60 Co source, with an average dose rate of ca. 240 Gy/min (Institute of Applied Chemistry of Peking University). The absorbed dose was traced by a Fricke dosimeter. C. Extraction of Dy 3+ 2 The organic phase (0.5 mL) contained 20 mmol/L of iso butyl-BTP dissolved in [C 2 mim][NTf 2 ], and the aqueous phase (0.5 mL) contained 8 mmol/L of Dy 3+ . The extraction experiments were oscillated in a constant temperature incubator shaker, which maintained a thermo-stated water bath at 25 ℃ with a rotating speed of 120 rpm, then were centrifuged for 2 min to ensure that the two phases were completely separated. After phase separation, the aqueous solution was diluted with deionized water and the concentration of Dy 3+ in the diluted aqueous solution was measured by the Prodigy high dispersion inductively coupled plasma atomic emission spectrometer (ICPS-7510, SHIMADZU, JPN). The distribution ratios ( D Dy ) were calculated by D Dy = ( C i - C f )/ C f and the calculation of extraction efficiencies ( E Dy ) was based on D Dy = ( C i - C f )/ i , where C i and C f designate the initial and final concentrations of Dy 3+ in the diluted aqueous solution, respectively. D. Characterization 2 Micro-FTIR. The Micro Fourier transform infrared spectroscopies (Micro-FTIR) were recorded on a Thermo Scientific Micro Fourier transform infrared spectrometry. 1 H and 19 F NMR. NMR experiments were carried out with a Bruker AV-500. The chemical shift scale was calibrated with tetramethylsilane at 0 ppm and NTf 2 - at -78.87 ppm for 1 H NMR and 19 F NMR, respectively. Ion chromatography analysis. The water-soluble products from the irradiated samples were analyzed using a MIC ion chromatography (IC) System (Metrohm Swiss). A Metrosep A SUPP 5-250 column (4 mm×250 mm) was used to provide a quantitative study on the radiolytic products of [C 2 mim][NTf 2 ] ionic liquids. The 819 IC conductivity detector was applied and the injection volume was set at 10 μL. The eluent was 3.2 mmol/L Na 2 CO 3 /1.0 mmol/L NaHCO 3 solution at a constant flow rate of 0.7 mL/min. The operating back pressure was 11.6 MPa. XPS analysis. The X-ray photoelectron spectra (XPS) of the samples were recorded by an AXIS-Ultra instrument from Kratos Analytical using monochromatic Al K α radiation and low energy electron flooding for charge compensation. III. RESULTS AND DISCUSSION 1 A. Identification of water-soluble radiolytic products of [C 2 mim][NTf 2 ] under γ-radiation 2 The water-washed sample of irradiated [C 2 mim][NTf 2 ] was analyzed by Micro-FTIR based on previous work [ 26 26 ]. As illustrated in Fig. 2 Fig. 2 , the Micro-FTIR spectrum of irradiated sample changes obviously in comparison with that of unirradiated sample. The absorption is band at 1136 cm -1 (1350 cm -1 ), corresponding to the vibration of the C - F bonds (S=O) of NTf 2 - , dropping obviously after γ-radiation. This indicated that C - F and S=O bonds were broken during irradiation. In addition, OH groups (NH 2 groups) are observed at 1655 cm -1 and 3450 cm -1 (960 cm -1 ) in Fig. 2b Fig. 2b . These results indicate that the radiolytic products containing OH and NH 2 groups were formed after irradiation. These results are similar to that of [C 4 mim][NTf 2 ] during irradiation [ 26 26 ] because [C 2 mim][NTf 2 ] has analogous anion ions (NTf 2 - ) with [C 4 mim][NTf 2 ]. Hence, the observed results in Micro-FTIR are mainly attributed to the radiolysis of [NTf 2 ] anions. 1 H NMR and 19 F NMR were employed to identify the radiolytic products of [C 2 mim][NTf 2 ] after irradiation. As shown in Fig. 3 Fig. 3 , no discernible changes was observed in 1 H NMR at 500 kGy, suggesting that the nonvolatile radiolysis products of [C 2 mim][NTf 2 ] do not exceed 1%. However, the peak of water broadened and shifted toward the low field after irradiation. This is consistent with information reported by Yuan et al ., who found that the change of water peak shape was attributed to the acidic radiolytic products [ 28 28 ]. Therefore, acidic radiolytic products were formed during the irradiation of [C 2 mim][NTf 2 ]. The 19 F NMR spectra of [C 2 mim][NTf 2 ] before and after irradiation are shown in Fig. 4 Fig. 4 . A single peak at -78.78 ppm, which is assigned to NTf 2 - was observed. Similar to the radiolysis of [C 4 mim][NTf 2 ] [ 26 26 ], several fluorine-containing compounds in irradiated [C 2 mim][NTf 2 ] have been identified as CF 3 SOONH 2 (-79.33 ppm), CF 3 SOOH (-87.08 ppm), HF (-164.55 ppm), and SiF 6 2- (-129.56 ppm) [ 26 26 ]. However, a new radiolytic product, which was not observed in irradiated [C 4 mim][NTf 2 ], is shown at -76.75 ppm. The difference in alkyl chain between C 2 mim + and C 4 mim + leads to the formation of different radiolytic products. B. A quantitative analysis of trace water-soluble radiolytic products of [C 2 mim][NTf 2 ] under γ-irradiation 2 Ion chromatography was employed to provide a quantitative analysis of these water-soluble radiolytic products (HF, CF 3 SOOH, and H 2 SO 3 ) and the experimental details are given in a previous paper [ 26 26 ]. As indicated in Fig. 5 Fig. 5 , the amounts of radiolytic products increased obviously with the increase of each dose. For instance, the concentration of F - increased from 0.030 mmol/L at 100 kGy to 0.087 mmol/L at 500 kGy. The G value of HF, CF 3 SOOH, and H 2 SO 3 was calculated at 0.22 μmol/L, 0.035 μmol/L, and 0.029 μmol/L, respectively. Compared with the G value of acidic radiolytic products of [C 4 mim][NTf 2 ] ( Table 1 Table 1 ), the radiolysis of [C 2 mim][NTf 2 ] is close to that of [C 4 mim][NTf 2 ]. The quantitative study using ion chromatography indicated that the overall concentration of nonvolatile acidic radiolysis products was less than 1% for [C 2 mim][NTf 2 ] even at 500 kGy, in which the results show that [C 2 mim][NTf 2 ] still has excellent radiation stability under γ-irradiation. a Data was obtained from Ref. [ 26 26 ]. 1 1 RTILs 1 1 G(F - ) (μmol/J) 1 1 G(CF 3 SOO - ) (μmol/J) 1 1 G(SO 3 2- ) (μmol/J) 1 1 [C 2 mim][NTf 2 ] 1 1 0.22 1 1 0.035 1 1 0.029 1 1 [C 4 mim][NTf 2 ]  a a 1 1 0.20 1 1 0.010 1 1 0.031 C. The influence of acidic radiolytic products of [C 2 mim][NTf 2 ] on the extraction of Dy 3+ 2 The influence of dose on Dy 3+ extraction was shown in Fig. 6 Fig. 6 . An abnormal increase of Dy 3+ partitioning is obtained when irradiated [C 2 mim][NTf 2 ] is used as extracting solvent. Some water-insoluble compounds were observed at the interface between irradiated [C 2 mim][NTf 2 ] and the aqueous solution. After the irradiated [C 2 mim][NTf 2 ] was washed by deionized water 3 times, Dy 3+ partitioning recovered to the unirradiated level. These results suggest that the abnormal increase of D Dy in irradiated [C 2 mim][NTf 2 ] is ascribed to the influence of water-soluble radiolytic products. Based on our previous work [ 27 27 ], Dy 3+ is precipitated with the radiolytic products generated from ionic liquid (F, SO 3 2- ), resulting in the increase of Dy 3+ partitioning in irradiated [C 2 mim][NTf 2 ]. After centrifuging and washing and drying, the white sediment was obtained and analyzed by XPS. The binding energies were calibrated using the C1s hydrocarbon peak at 284.80 eV. The composition of sediment was determined to consist of F, O, S and Dy elements according to the XPS record ( Fig. 7 Fig. 7 ), indicating the main components of the sediment are DyF 3 and Dy 2 (SO 3 ) 3 . Similar results have been reported in the α-radiolysis of [C 4 mim][NTf 2 ] ionic liquid irradiated with the helium ion beam [ 27 27 ]. Consequently, the increase of Dy 3+ partitioning in irradiated [C 2 mim][NTf 2 ] is due to the precipitation between the water-soluble radiolytic products of [C 2 mim][NTf 2 ] with Dy 3+ . IV. CONCLUSION 1 The main water-soluble radiolytic products of [C 2 mim][NTf 2 ] (CF 3 SOOH, CF 3 SO 2 NH 2 , HF and H 2 SO 3 ) under γ-irradiation were systematically investigated by using micro-FTIR, 1 H NMR, 19 F NMR, and ion chromatography. The radiolytic products of [C 2 mim][NTf 2 ] are similar to that of [C 4 mim][NTf 2 ], because the two ionic liquids have a similar chemical structure and the same anion ions. The radiolytic behavior of [C 2 mim][NTf 2 ] changes slightly compared to [C 4 mim][NTf 2 ] as the difference of the alkyl chain length. The extracting behavior of Dy 3+ using irradiated [C 2 mim][NTf 2 ] in combination with iso butyl-BTP showed an abnormal increase of Dy 3+ partitioning due to the precipitation between the acidic radiolytic products of the anion with Dy 3+ . The water-washing is a very effective and easy method to avoid the influence of radiolytic products of [C 2 mim][NTf 2 ]. This work provides an assessment about the feasibility of [C 2 mim][NTf 2 ] as alternative medium for the separations of MA-Ln from spent nuclear fuel. References V Alexander . Design and synthesis of macrocyclic ligands and their complexes of lanthanides and actinides . Chem Rev , 1995 , 95 : 273 - 342 . DOI: 10.1021/cr00034a002 http://doi.org/10.1021/cr00034a002 Design and synthesis of macrocyclic ligands and their complexes of lanthanides and actinides K L Nash . A review of the basic chemistry and recent developments in trivalent f-elements separations . Solvent Extr Ion Exc , 1993 , 11 : 729 - 768 . DOI: 10.1080/07366299308918184 http://doi.org/10.1080/07366299308918184 A review of the basic chemistry and recent developments in trivalent f-elements separations J Mathur , M Murali , K Nash . Actinide partitioning—a review . Solvent Extr Ion Exc , 2001 , 19 : 357 - 390 . DOI: 10.1081/SEI-100103276 http://doi.org/10.1081/SEI-100103276 Actinide partitioning—a review P J Panak and A Geist . Complexation and extraction of trivalent actinides and lanthanides by triazinylpyridine n-donor ligands . Chem Rev , 2013 , 113 : 1199 - 1236 . DOI: 10.1021/cr3003399 http://doi.org/10.1021/cr3003399 Complexation and extraction of trivalent actinides and lanthanides by triazinylpyridine n-donor ligands H H Dam , D N Reinhoudt , W Verboom . Multicoordinate ligands for actinide/lanthanide separations . Chem Soc Rev , 2007 , 36 : 367 - 377 . DOI: 10.1039/B603847F http://doi.org/10.1039/B603847F Multicoordinate ligands for actinide/lanthanide separations V A Cocalia , K E Gutowski , R D Rogers . The coordination chemistry of actinides in ionic liquids: A review of experiment and simulation . Coordin Chem Rev , 2006 , 250 : 755 - 764 . DOI: 10.1016/j.ccr.2005.09.019 http://doi.org/10.1016/j.ccr.2005.09.019 The coordination chemistry of actinides in ionic liquids: A review of experiment and simulation Z Kolarik , U Mullich , F Gassner . SELECTIVE EXTRACTION OF Am (III) OVER Eu (III) BY 2, 6-DITRIAZOLYL-AND 2, 6-DITRIAZINYLPYRIDINES 1 . Solvent Extr Ion Exc , 1999 , 17 : 1155 - 1170 . DOI: 10.1080/07360299908934598 http://doi.org/10.1080/07360299908934598 SELECTIVE EXTRACTION OF Am (III) OVER Eu (III) BY 2, 6-DITRIAZOLYL-AND 2, 6-DITRIAZINYLPYRIDINES 1 S Trumm , A Geist , P J Panak , et al . An improved hydrolytically-stable bis-triazinyl-pyridine (BTP) for selective actinide extraction . Solvent Extr Ion Exc , 2011 , 29 : 213 - 229 . DOI: 10.1080/07366299.2011.539129 http://doi.org/10.1080/07366299.2011.539129 An improved hydrolytically-stable bis-triazinyl-pyridine (BTP) for selective actinide extraction M Nilsson , S Andersson , F Drouet , et al . Extraction Properties of 6, 6’-Bis-(5, 6-dipentyl-[1, 2, 4] triazin-3-yl)-[2, 2’] bipyridinyl (C5-BTBP) . Solvent Extr Ion Exc , 2006 , 24 : 299 - 318 . DOI: 10.1080/07366290600646947 http://doi.org/10.1080/07366290600646947 Extraction Properties of 6, 6’-Bis-(5, 6-dipentyl-[1, 2, 4] triazin-3-yl)-[2, 2’] bipyridinyl (C5-BTBP) M J Hudson , C E Boucher , D Braekers , et al . New bis (triazinyl) pyridines for selective extraction of americium (III) . New J Chem , 2006 , 30 : 1171 - 1183 . DOI: 10.1039/B514108G http://doi.org/10.1039/B514108G New bis (triazinyl) pyridines for selective extraction of americium (III) T Welton . Room-temperature ionic liquids . Solvents for synthesis and catalysis. Chem Rev , 1999 , 99 : 2071 - 2084 . DOI: 10.1021/cr980032t http://doi.org/10.1021/cr980032t Room-temperature ionic liquids F Endres and S Z El Abedin . Air and water stable ionic liquids in physical chemistry . Phys Chem Chem Phys , 2006 , 8 : 2101 - 2116 . DOI: 10.1039/B600519P http://doi.org/10.1039/B600519P Air and water stable ionic liquids in physical chemistry N V Plechkova and K R Seddon . Applications of ionic liquids in the chemical industry . Chem Soc Rev , 2008 , 37 : 123 - 150 . DOI: 10.1039/B006677J http://doi.org/10.1039/B006677J Applications of ionic liquids in the chemical industry M L Dietz . Ionic liquids as extraction solvents: Where do we stand? Separ Sci Technol , 2006 , 41 : 2047 - 2063 . DOI: 10.1080/01496390600743144 http://doi.org/10.1080/01496390600743144 Ionic liquids as extraction solvents: Where do we stand? K Binnemans . Lanthanides and actinides in ionic liquids . Chem Rev , 2007 , 107 : 2592 - 2614 . DOI: 10.1021/cr050979c http://doi.org/10.1021/cr050979c Lanthanides and actinides in ionic liquids H Tokuda , S Tsuzuki , M Susan , et al . How ionic are room-temperature ionic liquids? An indicator of the physicochemical properties . J Phys Chem B , 2006 , 110 : 19593 - 19600 . DOI: 10.1021/jp064159v http://doi.org/10.1021/jp064159v How ionic are room-temperature ionic liquids? An indicator of the physicochemical properties ML Dietz , S Jakab , K Yamato , et al . Stereochemical effects on the mode of facilitated ion transfer into room-temperature ionic liquids . Green Chem , 2008 , 10 : 174 - 176 . DOI: 10.1039/B713750H http://doi.org/10.1039/B713750H Stereochemical effects on the mode of facilitated ion transfer into room-temperature ionic liquids S Dai , Y Ju , C Barnes . Solvent extraction of strontium nitrate by a crown ether using room-temperature ionic liquids . J Chem Soc Dalton , 1999 , 1201 - 1202 . DOI: 10.1039/A809672D http://doi.org/10.1039/A809672D Solvent extraction of strontium nitrate by a crown ether using room-temperature ionic liquids D Allen , G Baston , A E Bradley , et al . An investigation of the radiochemical stability of ionic liquids . Green Chem , 2002 , 4 : 152 - 158 . DOI: 10.1039/B111042J http://doi.org/10.1039/B111042J An investigation of the radiochemical stability of ionic liquids M Y Qi , G Z Wu , S M Chen , et al . Gamma radiolysis of ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate . Radiat Res , 2007 , 167 : 508 - 514 . DOI: 0033-7587/07 http://doi.org/0033-7587/07 Gamma radiolysis of ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate S E Howett , J M Joseph , J J Noel , et al . Effect of gamma irradiation on gas-ionic liquid and water-ionic liquid interfacial stability . J Colloid Interf Sci , 2011 , 361 : 338 - 350 . DOI: 10.1016/j.jcis.2011.05.034 http://doi.org/10.1016/j.jcis.2011.05.034 Effect of gamma irradiation on gas-ionic liquid and water-ionic liquid interfacial stability L Y Yuan , C Xu , J Peng , et al . Identification of the radiolytic product of hydrophobic ionic liquid [C4mim][NTf2] during removal of Sr2+ from aqueous solution . Dalton T , 2009 , 7873 - 7875 . DOI: 10.1039/B911026G http://doi.org/10.1039/B911026G Identification of the radiolytic product of hydrophobic ionic liquid [C4mim][NTf2] during removal of Sr2+ from aqueous solution L Y Yuan , J Peng , L Xu , et al . Radiation effects on hydrophobic ionic liquid [C4mim][NTf2] during extraction of strontium ions . J Phys Chem B , 2009 , 113 : 8948 - 8952 . DOI: 10.1021/jp9016079 http://doi.org/10.1021/jp9016079 Radiation effects on hydrophobic ionic liquid [C4mim][NTf2] during extraction of strontium ions L Y Yuan , J Peng , L Xu , et al . Influence of γ-radiation on the ionic liquid [C 4 mim][PF 6] during extraction of strontium ions . Dalton T , 2008 , 6358 - 6360 . DOI: 10.1039/B811413G http://doi.org/10.1039/B811413G Influence of γ-radiation on the ionic liquid [C 4 mim][PF 6] during extraction of strontium ions L Berthon , S Nikitenko , I Bisel , et al . Influence of gamma irradiation on hydrophobic room-temperature ionic liquids [BuMeIm] PF 6 and [BuMeIm](CF 3 SO 2) 2 N . Dalton T , 2006 , 2526 - 2534 . DOI: 10.1039/B601111J http://doi.org/10.1039/B601111J Influence of gamma irradiation on hydrophobic room-temperature ionic liquids [BuMeIm] PF 6 and [BuMeIm](CF 3 SO 2) 2 N Y Y Ao , J Peng , L Y Yuan , et al . Identification of radiolytic products of [C 4 mim][NTf 2] and their effects on the Sr 2+ extraction . Dalton T , 2013 , 42 : 4299 - 4305 . DOI: 10.1039/c2dt32418k http://doi.org/10.1039/c2dt32418k Identification of radiolytic products of [C 4 mim][NTf 2] and their effects on the Sr 2+ extraction Y Y Ao , H Y Zhou , W J Yuan , et al . α-Radiolysis of ionic liquid irradiated with helium ion beam and the influence of radiolytic products on Dy 3+ extraction . Dalton T , 2014 , 43 : 5580 - 5585 . DOI: 10.1039/c3dt53297f http://doi.org/10.1039/c3dt53297f α-Radiolysis of ionic liquid irradiated with helium ion beam and the influence of radiolytic products on Dy 3+ extraction L Y Yuan , J Peng , L Xu , et al . Radiation effects on hydrophobic ionic liquid [C4mim][NTf2] during extraction of strontium ions . J Phys Chem B , 2009 , 113 : 8948 - 8952 . DOI: 10.1021/jp9016079 http://doi.org/10.1021/jp9016079 Radiation effects on hydrophobic ionic liquid [C4mim][NTf2] during extraction of strontium ions I Billard , A Ouadi , C Gaillard . Is a universal model to describe liquid-liquid extraction of cations by use of ionic liquids in reach? Dalton T , 2013 , 42 : 6203 - 6212 . DOI: 10.1039/C3DT32159B http://doi.org/10.1039/C3DT32159B Is a universal model to describe liquid-liquid extraction of cations by use of ionic liquids in reach? A Bhattacharyya , P Mohapatra , A Roy , et al . Ethyl-bis-triazinylpyridine (Et-BTP) for the separation of americium (III) from trivalent lanthanides using solvent extraction and supported liquid membrane methods . Hydrometallurgy , 2009 , 99 : 18 - 24 . DOI: 10.1016/j.hydromet.2009.05.020 http://doi.org/10.1016/j.hydromet.2009.05.020 Ethyl-bis-triazinylpyridine (Et-BTP) for the separation of americium (III) from trivalent lanthanides using solvent extraction and supported liquid membrane methods 10.13538/j.1001-8042/nst.26.S10306 Supported by the Ph.D. Programs Foundation of Ministry of Education of China (No. 20130073120051), the Program for Professor of Special Appointment (Eastern Scholar) at Shanghai Institutions of Higher Learning, and the National Natural Science Foundation of China (No. 11475112) 2014-05-19 2014-06-23 2014-12-20 2015-02-20 2021-04-11 2015 Nuclear Science and Techniques 1 26