Solution extraction of several lanthanides from nitric acid with isohexyl-BTP in [Cnmim][NTf2] ionic liquid
来源期刊：Journal of Rare Earths2015年第11期
论文作者：赵龙 董珍 马国龙 袁威津
文章页码：1182 - 1188
摘 要：The extraction behavior of several lanthanides（La3+, Eu3+, Lu3+） from nitric acid（HNO3） solution was studied using a novel extraction system based on 2,6-bis（5,6-dihexyl-1,2,4-triazin-3-yl） pyridine（isohexyl-BTP） as extractant in 1-alkyl-3-methylimidazolium bis（trifluoromethylsufonyl）imide（[Cnmim][NTf2]） ionic liquid. Isohexyl-BTP in ionic liquids exhibited remarkably better extraction performance for lanthanides than that in octanol-dodecane（3:7 v/v） system. Lower HNO3 concentration and short alkyl chain length of [Cnmim]+ were more favourable for removal of lanthanides. Besides, it was confirmed that isohexyl-BTP in ILs formed a 1:3 complex [Ln（BTP）3（NO3）n]（3–n）+（n=0, 1） by slope analysis. In addition, [C2mim][NTf2] preferred to extract lanthanides via a cation exchange mechanism at lower acidity, which was proved via UV-Vis measurement. It was speculated that extraction mechanism shifted from cation exchange to neutral species extraction with increase in HNO3 concentration and alkyl chain length of [Cnmim]+ due to the H+ completion, NO–3 inhibition and hydrophobicity of IL.
赵龙1,2，董珍1,2，马国龙2，袁威津2
1. Non-power Nuclear Technology Collaborative Innovation Center, School of Nuclear Technology and Chemistry & Life Science, Hubei University of Science and Technology2. Nuclear Chemical Engineering Laboratory, School of Nuclear Science and Engineering, Shanghai Jiao Tong University
摘 要：The extraction behavior of several lanthanides（La3+, Eu3+, Lu3+） from nitric acid（HNO3） solution was studied using a novel extraction system based on 2,6-bis（5,6-dihexyl-1,2,4-triazin-3-yl） pyridine（isohexyl-BTP） as extractant in 1-alkyl-3-methylimidazolium bis（trifluoromethylsufonyl）imide（[Cnmim][NTf2]） ionic liquid. Isohexyl-BTP in ionic liquids exhibited remarkably better extraction performance for lanthanides than that in octanol-dodecane（3:7 v/v） system. Lower HNO3 concentration and short alkyl chain length of [Cnmim]+ were more favourable for removal of lanthanides. Besides, it was confirmed that isohexyl-BTP in ILs formed a 1:3 complex [Ln（BTP）3（NO3）n]（3–n）+（n=0, 1） by slope analysis. In addition, [C2mim][NTf2] preferred to extract lanthanides via a cation exchange mechanism at lower acidity, which was proved via UV-Vis measurement. It was speculated that extraction mechanism shifted from cation exchange to neutral species extraction with increase in HNO3 concentration and alkyl chain length of [Cnmim]+ due to the H+ completion, NO–3 inhibition and hydrophobicity of IL.
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