The extraction behavior of several lanthanides（La^3＋, Eu^3＋, Lu^3＋） 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（isohe...The extraction behavior of several lanthanides（La^3＋, Eu^3＋, Lu^3＋） 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, NO3^- inhibition and hydrophobicity of IL.展开更多
The chemistry of extraction of lanthanide and yttrium by 2-ethylhexylphosphonic acidmono-2-ethylhexyl ester in n-dodecane from nitric acid is described. By M W determination, NMR and the slope method, the extraction r...The chemistry of extraction of lanthanide and yttrium by 2-ethylhexylphosphonic acidmono-2-ethylhexyl ester in n-dodecane from nitric acid is described. By M W determination, NMR and the slope method, the extraction reaction is studied.Based upon elementery analyses, IR, NMR as well as MW determination, the compositions ofthe complexes formed with La（NO3）3 and Nd（NO3）3 are studied. Both the standard enthalprchanges（-△H°） and the relative free energy and entropy changes （-△Zr°）（△SPr°）of the ex-.traction reaction are also estimated. The regularity of the variations of Kea（concentrationequilibrium constant）, -△AZr° and △Sr°reveals the tetrad effect. The average separationfactor of the adjacent lanthanides is calculated to be as high as 3.04.展开更多
基金supported by the National Natural Science Foundation of China(11475112)the Ph.D.Programs of Foundation of Ministry of Education of China(20130073120051)
文摘The extraction behavior of several lanthanides（La^3＋, Eu^3＋, Lu^3＋） 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, NO3^- inhibition and hydrophobicity of IL.
文摘The chemistry of extraction of lanthanide and yttrium by 2-ethylhexylphosphonic acidmono-2-ethylhexyl ester in n-dodecane from nitric acid is described. By M W determination, NMR and the slope method, the extraction reaction is studied.Based upon elementery analyses, IR, NMR as well as MW determination, the compositions ofthe complexes formed with La（NO3）3 and Nd（NO3）3 are studied. Both the standard enthalprchanges（-△H°） and the relative free energy and entropy changes （-△Zr°）（△SPr°）of the ex-.traction reaction are also estimated. The regularity of the variations of Kea（concentrationequilibrium constant）, -△AZr° and △Sr°reveals the tetrad effect. The average separationfactor of the adjacent lanthanides is calculated to be as high as 3.04.
