摘要
The strontium ions extracted from the aqueous phase into 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide(C_2mimNTf2) with dicyclohexyl-18-crown-6(DCH18C6) was stripped effectively by supercritical CO_2(sc-CO_2).Hexafluoroacetylacetone(HFAA)-acetonitrile was found to be an excellent modifier of sc-CO_2 to enhance the stripping efficiency.In the orthogonal array design(OAD),OA_(25)(5~5)matrix was employed to optimize the stripping of Sr(Ⅱ) from the DCH 18C6-C_2mimNTf_2 system.Effects of five experimental factors:temperature,pressure,concentration of HFAA,static and dynamic extraction times as well as each factor at five-levels on the stripping of Sr(Ⅱ) were optimized.The effects of these parameters were treated by the analysis of variance(ANOVA).The results showed that Sr(II) could be nearly 100%extracted from the IL phase at 308 K,30 MPa,40 min of dynamic extraction and 60 mmol·L^(-1) HFAA in acetonitrile,respectively.Finally,the stripping mechanism was studied by ESI-MS.
The strontium ions extracted from the aqueous phase into 1-ethyl-3-methylimidazolium bis（trifluoromethylsulfonyl）imide（C2mimNTf2） with dicyclohexyl-18-crown-6（DCH18C6） was stripped effectively by supercritical CO2（sc-CO2）.Hexafluoroacetylacetone（HFAA）-acetonitrile was found to be an excellent modifier of sc-CO2 to enhance the stripping efficiency.In the orthogonal array design（OAD）,OA（25）（5~5）matrix was employed to optimize the stripping of Sr（Ⅱ） from the DCH 18C6-C_2mimNTf_2 system.Effects of five experimental factors：temperature,pressure,concentration of HFAA,static and dynamic extraction times as well as each factor at five-levels on the stripping of Sr（Ⅱ） were optimized.The effects of these parameters were treated by the analysis of variance（ANOVA）.The results showed that Sr（II） could be nearly 100%extracted from the IL phase at 308 K,30 MPa,40 min of dynamic extraction and 60 mmol·L^-1 HFAA in acetonitrile,respectively.Finally,the stripping mechanism was studied by ESI-MS.
基金
Supported by the National Natural Science Foundation of China(91226112)
