硝酸体系中双功能离子液体萃取剂[A336][CA-12]/[A336][CA-100]萃取稀土的机理研究

研究了双功能离子液体萃取剂[A336][CA-12]/[A336][CA-100]在HNO3体系中对稀土的萃取性能。通过与有机羧酸类萃取剂CA-12/CA-100及中性有机膦(磷)类萃取剂TBP和P350的比较得知,在相同条件下,萃取能力按如下顺序降低:[A336][CA-12]/[A336][CA-100]>CA-12/CA-100>P350>TBP。利用斜率法探讨了[A336][CA-12]/[A336][CA-100]萃取稀土的机理和反应方程式,表明双功能离子液体萃取剂[A336][CA-12]/[A336][CA-100]在HNO3体系中对稀土萃取符合离子络合机理。同时考察了萃取时间以及温度对萃取性能的影响。结果显示,双功能离子液体萃取剂[A336][CA-12]/[A336][CA-100]在HNO3体系中萃取稀土是快速平衡的放热反应。而循环和反萃实验说明双功能离子液体萃取剂[A336][CA-12]/[A336][CA-100]稳定性好,易反萃,是一种富集分离稀土的优良萃取剂。

离子液体萃取剂Cyphos IL101从氯化体系中萃取分离铜/镍行为及机制

研究了以离子液体Cyphos IL101为萃取剂从氯化体系中萃取分离铜、镍,考察了溶液酸度、氯离子浓度、萃取剂体积分数、水相pH对铜、镍萃取分离的影响。结果表明:Cyphos IL101能从氯化体系中高效萃取铜,而镍几乎不被萃取;在盐酸浓度3mol/L条件下,萃取分离系数β(Cu/Ni)达49 050.38;铜萃取率随氯离子浓度升高而提高,但不受水相pH影响。分别用硝酸、硫酸和纯水对负载铜有机相进行反萃取,结果表明:硝酸和硫酸对铜的反萃取率均高于90%,而水较难实现反萃取。采用斜率法对萃取机制进行分析,结果表明:Cyphos IL101通过氯阴离子交换与铜以物质的量比1∶1进行萃取,萃取产物为R3R’PCuCl_3。水相和有机相的UV-Vis光谱、Raman光谱及XPS能谱分析结果表明,氯化体系中,[CuCl_4]^(2-)为有效萃合物结构。由于优良的离子交换萃取性能,Cyphos IL101有望成为一种新型高效分离铜镍的优良萃取剂。

Kinetics of cerium(Ⅳ) and fluoride extraction from sulfuric solutions using bifunctional ionic liquid extractant(Bif-ILE)[A336][P204]

The extraction kinetics of Ce（Ⅳ） and Ce（Ⅳ）-F^- mixture systems from sulfuric solutions to n-heptane solution containing Bif-ILE[A336][P204]（[trialkylmethylammonium][di-2-ethylhewanxylphosphinate]） with a constant interfacial area cell with laminar flow were studied,just to elucidate the extraction mechanism and the mass transfer models.The data were analyzed in terms of pseudo-first-order constants.The effects of stirring speed,specific interfacial area and temperature on the extraction rate in both systems were discussed,suggesting that the extractions were mixed bulk phases-interfacial control process.Supported by the experimental data,the corresponding rate equations for Ce（Ⅳ） extraction system and Ce（Ⅳ）-F^- mixture extraction system were obtained.The experimental results indicated the rate-controlling step.The kinetics model was deduced from the rate-controlling step and consistent with the rate equation.

Simulation for Transesterification of Methyl Acetate and n-Butanol in a Reactive and Extractive Distillation Column Using Ionic Liquids as Entrainer and Catalyst

A new reactive and extractive distillation process with ionic liquids as entrainer and catalyst （RED-IL）was proposed to produce methanol and n-butyl acetate by transesterification reaction of methyl acetate with n-butanol. The RED-IL process was simulated via a rigorous model, and high purity products of methanol and n-butyl acetate can be obtained in such a process. The effects of reflux ratio, feed mode, holdup, feed location, entrainer ratio and catalyst concentration on RED-IL process were investigated. The conversion of methyl acetate and purities of products increase with the holdup in column, entrainer ratio and catalyst content. An optimal reflux ratio exists in RED-IL process. Comparing to the mixed-feed mode, the segregated-feed mode is more effective, in which the optimal feed locations of reactants exist.

Solvent Extraction of Yttrium by Task-specific Ionic Liquids Bearing Carboxylic Group

A new kind of hydrophobic ionic liquids [1-alkyl-3-（1-carboxylpropyl）im][PF6] has been synthesized, and their extraction.properties for Y（III） in the nitric acid medium was also investigated. The effects of extractant concentration, equilibrium pH of aqueous phase, salt concentration, temperature etc. were discussed. The results show that this kind of Task-Specific Ionic Liquid （TSIL） needs to be saponified before being used for the Y（III） extraction, and the extraction is-acid dependent,-and the extraction efficiency increases with the aqueous phase acldity decreasing. Furthermore, the loaded organic phase is easy to be stripped; more than 95% Y（III） could be stripped from the loaded organic phase when the stripping acidity is higher than 0.07 mol-L-1. The slope analysis technique is used to investigate the extraction mechanism, and a possible cation-exchange extraction mechanism is proposed in the oresent extraction system.

Application of bifunctional ionic liquids for extraction and separation of Eu^(3+) from chloride medium

The extraction of Eu^(3+)from chloride medium using bifunctional ionic liquid extractants(Bif-ILEs)tri-n-octylmethyl ammonium bis(2-ethyl hexyl)phosphate([A336][D2EHP])and trihexyltetradecyl phosphonium bis(2-ethylhexyl)phosphate([P_(66614)][D2EHP])in kerosene was studied to develop environmentally friendly extraction process.The extraction behavior of Eu^(3+)was examined by varying key process parameters.The extraction behavior indicates that ammonium-based ionic liquid[A336][D2EHP]shows better extraction efficiency of Eu^(3+)than that of phosphonium-based ionic liquid[P_(66614)][D2EHP].Quantitative extraction of Eu^(3+)is obtained with 0.05 mol/L[A336][D2EHP],whereas,0.1 mol/L of[P_(66614)][D2EHP]is required to achieve the same extraction rate of Eu^(3+).The extraction process is endothermic with respect to[A336][D2EHP].Stripping experiments indicate that 100%of Eu^(3+)can be back extracted from both the loaded ionic liquids using 20 vol.%HNO_(3).The highest separation factor(βY/Eu)of 653.59 is reported at pH of 3.2,and the separation factor of Eu^(3+)over La^(3+)is 30.6 at the same pH.From the leach liquors of waste tube light powder,99.98%of Eu and 99.99%Y are recovered using 0.2 mol/L[A336][D2EHP]in 2-stage cross current extraction with aqueous to organcic ratio(O/A)of 1:1 and 1:2.

Extraction mechanism of rare earths from chloride acidic solution with ammonium-bifunctionalized ionic liquid extractants

A series of ammonium-bifunctionalized ionic liquid extractants （ammonium-Bif-ILEs） combined with a number of anions, in- cluding carboxylic acids and 1,3-diketonates, have been prepared and studied in this report. Their extraction behavior and properties toward rare earth ions （REs（III）） are systematically investigated in chloride media as a function of important param- eters such as aqueous phase pH, salting-out agent concentrations, and extraction temperature. The separation performance of ammonium-Bif-ILEs toward REs（III） are systematically discussed. The results demonstrate that ammonium-Bif-ILEs have a synergistic effect between the cation and anions in separation of REs（III）. The influences of different anions on separation fac- tor （β） values are further studied. By comparison, ammonium-Bif-ILEs containing 1,3-diketonates have more potential appli- cations in La（III）/RE（III） separation than those containing carboxylic acids.

Solvent extraction of U(VI) by trioctylphosphine oxide using a room-temperature ionic liquid

The unique physical and chemical properties of room-temperature ionic liquids(RTILs) have recently received increasing attention as solvent alternatives for possible application in the field of nuclear industry, particularly in liquid-liquid separations of radioactive nuclides. We investigated solvent extraction of U(VI) from aqueous solutions into a commonly used ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide([C4mim][NTf2]) using trioctylphosphine oxide(TOPO) as an extractant. The effects of contact time, TOPO concentration, acidity, and nitrate ions on the U(VI) extraction are discussed in detail. The extraction mechanism was proposed based on slope analysis and UV-Vis measurement. The results clearly show that TOPO/[C4mim][NTf2] provides a highly efficient extraction of U(VI) from aqueous solution under near-neutral conditions. When the TOPO concentration was 10 mmol/L, the extraction of 1 mmol/L U(VI) was almost complete(> 97%). Both the extraction efficiency and distribution coefficient were much larger than in conventional organic solvents such as dichloromethane. Slope analysis confirmed that three TOPO molecules in [C4mim][NTf2] bound with one U(VI) ion and one nitrate ion was also involved in the complexation and formed the final extracted species of [UO2(NO3)(TOPO)3]+. Such a complex suggests that extraction occurs by a cation-exchange mode, which was subsequently evidenced by the fact that the concentration of C4mim+ in the aqueous phase increased linearly with the extraction percent of U(VI) recorded by UV-Vis measurement.