离子液体支撑液膜分离CO2

支撑液膜是一种在湿法冶金、生物技术以及气体分离等多个领域都有应用的重要膜分离技术。本文回顾了支撑液膜技术分离CO2的研究进展,按照液膜相的不同,分类介绍了常规载体支撑液膜和离子液体支撑液膜,指出了常规载体支撑液膜分离CO2的局限性,重点介绍了离子液体支撑液膜分离CO2的发展,分析了气体在离子液体支撑液膜中的传质机理以及常规离子液体结构、含量和支撑膜材料等对分离效果的影响;讨论了离子液体的功能化方法以及功能化离子液体支撑液膜分离CO2的渗透率、选择性和液膜稳定性;介绍了两种新的离子液体支撑液膜改进方法:聚离子液体膜与凝胶化离子液体支撑液膜。最后指出了今后用于CO2分离的离子液体支撑液膜的发展方向。     

液膜萃取技术在环境样品前处理中的应用

膜分离技术是利用膜对混合物中各组分的选择渗透性能的差异来实现分离、提纯和浓缩的新型分离技术。近年来,随着人们环保意识的加强,环境中污染物的监测逐渐被重视。因环境样品基体的复杂性,在分析测定前必须进行净化处理。将膜分离技术与液液萃取技术相结合的液膜萃取技术因其     

分散支撑液膜体系中Pb2+离子的传输

在现有支撑液膜分离技术的理论研究基础上,探索合适的液膜分离体系,研究了Pb(Ⅱ)在PC-88A-煤油-HCl分散支撑液膜体系中的传输行为;考察了料液pH值、膜溶液与解析剂体积比、解析相中HCl浓度以及Pb(Ⅱ)的起始浓度对Pb(Ⅱ)传输的影响。 结果表明,以HCl为解析剂,料液相pH=5.25、膜溶液与解析剂体积比为160∶40、解析相中HCl浓度为5.00 mol/L时,该分散支撑液膜体系对金属Pb(Ⅱ)具有良好的传输作用。 在选取的最佳传输条件下,料液相中Pb(Ⅱ)的初始浓度为3.00×10-4 mol/L时,传输190 min,传输率可达88.9％,而传统支撑液膜只有72.3％。 分散支撑液膜不仅具有较高的传输效率,而且膜体系稳定,膜的使用寿命长。     

金属离子提取的支撑型液膜稳定性:膜材料研究进展

支撑液膜是一种结合膜材料与萃取体系的高效率分离技术.然而在使用过程中,溶剂与萃取载体从多孔支撑体中流失和多孔膜材料在有机相载体中不稳定,导致支撑液膜通量的衰减或选择性降低,支撑液膜表现为不稳定,目前尚未见工业化的成功案例.本文简要介绍了支撑液膜不稳定机理,从膜材料角度,综述了提高支撑液膜稳定性的方法.重点介绍了液膜凝胶...     

钴(Ⅱ)在二-(2-乙基己基)膦酸/CHCl3支撑液膜体系中的传输

钴(Ⅱ)在二-(2-乙基己基)膦酸/CHCl3支撑液膜体系中的传输;液膜分离     

平板夹心型支撑液膜萃取体系中La^3＋的迁移行为

在含ＨＥＨ（ＥＨＰ）的平板夹心型支撑液膜萃取Ｌａ＾３＋的体系中，研究了体系传质过程中的渗透系数ｐ及其影响因素。实验证明夹心型与单型支撑液膜的传质理论模型以及料液酸度和反萃液酸度对传质渗透系数的影响基本一致。当体系料液的ｐＨ在３．５￣４．２之间时，体系的渗透系数ｐ趋于稳定；ｐ随反萃液酸度的增加而增大，当反萃液酸度大于４．０ｍｏｌ／Ｌ时，ｐ趋于恒定；比较了用不同材料和厚度的夹心型支撑液膜体系萃取ｌａ２     

苯酚在N-503/煤油支撑液膜体系中的传输分离

研究了以多孔聚丙烯膜为支撑体,N,N′-二(1-甲基庚基)乙酰胺(N-503)为膜流动载体的苯酚支撑液膜传输行为;用液-液萃取法测定了N-503/煤油体系中苯酚萃合物组成为1∶1,及在相应的条件下萃取常数Ke′x为53.7;考察了料液相的pH值、载体浓度、实验温度、起始浓度以及解析相NaOH的浓度对苯酚传输的影响,并对该体系分离、传输苯酚的最佳条件进行了讨论;从界面化学和扩散传质角度提出了苯酚的传输动力学方程,采用直线斜率法对苯酚在N-503/煤油支撑液膜体系中的扩散层厚度和膜内扩散系数进行了测定,取得满意结果。     

中空纤维管夹心型支撑液膜萃取体系中La^3＋的迁移行为

设计了含２－乙基己基膦酸单２－乙基己基酯的中空纤维管夹心型支撑液膜体系，并研究了Ｌａ＾３＋在该体系中的迁移行为。实验得出该体系液膜传质渗透系数ρ的数学表达式，测定体系中Ｌａ＾３＋传质渗透系数ρ及其影响因素；该体系在料液ｐＨ≥４时，Ｌａ＾３＋的传质渗透系数ρ趋于稳定，随着体系反萃酸度的增加，ρ值略有增加。与同类中空纤维管支撑液膜体系相比，该体系对稀土元素有较强的富集能力，且稳定性较好。     

液膜富集原子吸收分光光度法测定痕量钪

液膜富集原子吸收分光光度法测定痕量钪李龙泉孙晔淦五二李亚栋（中国科技大学应用化学系合肥２３００２６）关键词钪液膜原子吸收分光光度法液膜分离法具有简便、快速、选择性好、富集倍数和回收率高等优点。王雨春［１］等曾将其用于钪的分离；但未见用于痕量钪分离、富...     

多孔聚丙烯支撑液膜中镉的传输研究

研究了以多孔聚丙烯膜为支撑体, PC-88A/CHCl3为膜载体的金属离子 Cd(Ⅱ )支撑液膜传输行为; 考察了料液相 pH值、载体浓度、温度和起始浓度对 Cd(Ⅱ )传输的影响, 并对该体系富集、传输 Cd(Ⅱ )的最佳条件进行了讨论; 从界面化学和扩散传质角度提出了金属离子的传输动力学方程, 采用直线斜率法对 Cd(Ⅱ )在支撑液膜体系中的扩散层厚度(δ a=8.14× 10- 6 m)和膜内扩散系数( d0=5.43× 10- 10 m2/s)进行了测定, 取得满意结果.     

Continuous flow liquid membrane extraction: a novel automatic trace-enrichment technique based on continuous flow liquid-liquid extraction combined with supported liquid membrane

Combining the continuous flow liquid-liquid extraction (CFLLE) and supported liquid membrane (SLM) extraction, a novel aqueous-aqueous extraction technique that we termed continuous flow liquid membrane extraction (CFLME) is developed for trace-enrichment. The analyte was firstly extracted into the organic phase in the CFLLE step, then transported onto the organic liquid membrane that formed on the surface of the micro porous membrane of the SLM equipment. Finally, it passed through the liquid membrane and was trapped by the acceptor. Aspects related to CFLME were studied by using dichloromethane as liquid membrane, and sulfonylurea herbicides as model compounds. An enrichment factor of over 1000 was obtained when 10 μg l⁻¹ of MSM was enriched for 120 min by this technique. The drawbacks of only a few organic solvents can be selected as liquid membrane with a limited lifetime in SLM operation was overcome. In this CFLME method, almost all solvents that used in the conventional liquid-liquid extraction (LLE) can be adopted and the lifetime of liquid membrane is no longer a problem.     

Improved Response and Steady State Times For Fibre Optical Sensors by Supported Liquid Membranes

ABSTRACT|Selectivity of fibre optical sensors can be improved by replacing the neat polymer cladding of optical fibres with a supported liquid membrane (SLM). In the present application the combination polysiloxane/perfluorokerosene was chosen as SLM. Halogenated hydrocarbons have been analysed. In addition to the enhanced selectivity over the conventional polysiloxane membrane, the response time of the SLM decreases more rapidly upon increasing analyte concentration, and its steady state time is reduced to 50% for all concentrations.

However, the SLM detection limit deteriorates by a factor of 2.     

The Removal of Zn(II) Through Calix[4]Recorcinarene Derivative Based Polymer Inclusion Membrane From Aqueous Solution

In the present work, the transport of Zn(II) metal ion from an aqueous nitrate solution of different metal ions through a polymer inclusion membrane (PIM) containing calix[4]resorcinarene derivative used as a carrier were investigated. Zn(II)metal ion showing high permeability were transported through PIMs prepared from cellulose triacetate (CTA) as a polymeric support material and 2-NPOE as a plasticizer. Total Zn(II) concentration was determined with an Atomic Absorption Spectrometer (AAS) in the acceptor phase. The prepared PIM and supported liquid membrane (SLM) were characterized by using Scanning Electron Microscopy(SEM) and Atomic Force Microscopy (AFM) techniques. The effects of membrane composition, effects of type of plasticizer in the membrane, effects of carrier concentration, and the thickness of the membranes were examined in the facilitated transport experiments of Zn(II) ion through PIM. We compared the performance of SLM experiments under the optimum conditions identified by the PIM studies. Higher permeability coefficient values for Zn(II) was found for SLM, while lower values were ascertained for PIM. The kinetic parameters which have been calculated as the constant rate (k), permeability coefficient (P), flux (J) and diffusion coefficient (D).     

Effect of membrane preparation on the lifetime of supported liquid membranes

A new observation on the stability of supported liquid membranes (SLMs) is reported. Membranes prepared with ‘dry’ outer surfaces, free from organic wetting, were found to be more stable than the conventional SLM prepared with external surfaces wetted with a film of the organic membrane liquid phase. For copper transport the ‘dry’ surface SLM had a similar initial flux to the ‘wet’ surface SLM, and 2 to 4 times the flux after 100 h. Over a 50 h period the ‘dry’ SLM lost about 10% of its membrane liquid, whereas the ‘wet’ SLM lost about 50%. The difference is ascribed to the loss of membrane by emulsion formation at one of the aqueous-organic interfaces which would be greater for the ‘wet’ SLM with a continuous liquid film over the surface of the support.     

Multiresidue determination of sulfonamides in a variety of biological matrices by supported liquid membrane with high pressure liquid chromatography-electrospray mass spectrometry detection

A high performance liquid chromatography (HPLC) coupled to a mass spectrometer (MS) was used for a simultaneous determination of 16 sulfonamide compounds spiked in water, urine, milk, and bovine liver and kidney tissues. Supported liquid membrane (SLM) made up of 5% tri-n-octylphosphine oxide (TOPO) dissolved in hexyl amine was used as a sample clean-up and/or enrichment technique. The sulfonamides mixture was made up of 5-sulfaminouracil, sulfaguanidine, sulfamethoxazole, sulfamerazine, sulfamethizole, sulfamethazine (sulfadimidine), sulfacetamide, sulfapyridine, sulfabenzamide, sulfamethoxypyridazine, sulfamonomethoxine, sulfadimethoxine sulfasalazine, sulfaquinoxaline, sulfadiazine, and sulfathiazole. Some of these compounds, such as, sulfaquinoxaline, sulfadiazine, sulfabenzamide, sulfathiazole and sulfapyridine failed to be trapped efficiently by the same liquid membrane (5% TOPO in hexylamine). The detection limits (DL) obtained were 1.8 ppb for sulfaguanidine and sulfamerazine and between 3.3 and 10 ppb in bovine liver and kidney tissues for the other sulfonamides that were successfully enriched with SLM; 2.1 ppb for sulfaguanidine and sulfamerazine and between 7.5 and 15 ppb in cow’s urine, whereas the DL values in milk were 12.4 ppb for sulfaguanidine and sulfamerazine and between 16.8 and 24.3 for the other compounds that were successfully enriched by the membrane. Several factors affecting the extraction efficiency during SLM enrichment, such as donor pH, acceptor pH, enrichment time and the membrane solvent were studied.     

Stripping Analysis of Trace Metals at a Flow-Through Reticulated Vitreous Carbon Electrode after the Preconcentration by Supported Liquid Membrane Technique

Abstract

The performance of a flow-through mercury coated reticulated vitreous carbon (RVC) electrode in the potentiometric stripping analysis (PSA) of trace metals has been examined. A wall-jet glassy carbon cell was used for the comparative experiments. Experimental parameters influencing the stripping signals have been optimised in order to use the stripping analysis after the preconcentration and matrix isolation by supported liquid membrane (SLM) technique. The SLM with di-2-ethylhexyl-phosphoric acid (DEHPA) as the extractant in the membrane liquid for proton driven transport of trace metals across the membrane has been chosen. Results presented for lead determination in river water demonstrate the analytical advantages of coupled technique SLM-PSA.     

Facilitated transport of CO2 across a liquid membrane: Comparing enzyme, amine, and alkaline

In this work we compare the efficiency of facilitated transport of CO₂ across a liquid membrane by different facilitators as tested in either a supported liquid membrane (SLM) or a hollow fiber contained liquid membrane (HFCLM) configuration. Permeance and selectivity were evaluated by both experimental test and numerical simulation. These comparisons were used to define the best liquid membrane composition to maximize separation performance. We also consider other factors that affect the choice of the facilitator, e.g. operation temperature and cost. Under ambient operating conditions, carbonic anhydrase (CA) combined with an alkaline carbonate gives better performance than does diethanolamine (DEA).     

Facilitated transport of copper(II) across supported liquid membrane and polymeric plasticized membrane containing 3-phenyl-4-benzoylisoxazol-5-one as carrier

The potential of 3-phenyl-4-benzoylisoxazol-5-one (HPBI) as metal extractant has been evaluated for the first time for Cu(II) transport from aqueous nitrate solutions by supported liquid membrane (SLM) in the solvents chloroform, 2-nitro phenyl octyl ether (NPOE) and dodecyl nitro phenyl ether (DNPE). The efficiency of the membrane transport was optimized as a function of pH, temperature, aqueous phases and membrane composition. It follows the sequence CHCl₃ > DNPE > NPOE. The results suggested that the transport mechanism was mainly controlled by the diffusion of the Cu(PBI)₂ complex in the membrane core. A comparative investigation of Cu(II) transport ions has been made between SLM and polymeric plasticized membrane (PPM), containing HPBI with NPOE and DNPE as organic solvents or plasticizers in order to evaluate the feasibility of PPM with HPBI.     

Enzyme-facilitated enantioselective transport of (S)-ibuprofen through a supported liquid membrane based on ionic liquids

Coupling lipase reactions with a supported liquid membrane (SLM) based on ionic liquids showed facilitative and selective permeation of (S)-ibuprofen through the SLM, indicating successful optical resolution of a racemic mixture using the enzyme-facilitative SLM.