表面活性剂液膜萃取过程的乳液溶胀(Ⅰ)——载体对乳液溶胀的影响

研究了载体对乳液溶胀的影响。发现膜相中存在载体时使界面张力降低,说明载体能吸附于界面。表面活性剂和载体在界面的竞争吸附是影响乳液溶胀的关键因素。本研究表明,液膜的夹带溶胀随膜相中载体浓度的增大而减小,而渗透溶胀则随之而加剧。提出了估算溶胀率的修正方程,用修正方程对膜相存在载体时的乳液夹带溶胀率进行了估算,计算值与实验数据吻合良好。     

表面活性剂液膜萃取过程的乳液溶胀(Ⅰ)——载体对乳液溶胀的影响

研究了载体对乳液溶胀的影响。发现膜相中存在载体时使界面张力降低,说明载体能吸附于界面。表面活性剂和载体在界面的竞争吸附是影响乳液溶胀的关键因素。本研究表明,液膜的夹带溶胀随膜相中载体浓度的增大而减小,而渗透溶胀则随之而加剧。提出了估算溶胀率的修正方程,用修正方程对膜相存在载体时的乳液夹带溶胀率进行了估算,计算值与实验数据吻合良好。     

Membrane‐liquid emulsion membrane process using a liquid emulsion membrane process using methane sulfonic acid as a strippant

The application of a liquid emulsion membrane (LEM) process in the recovery of zinc from aqueous solutions is discussed. The role of a stripping agent is very important in the LEM extraction process. Various stripping agents, such as hydrochloric, sulfuric, nitric and methane sulfonic acids, were tested for the stability of membrane. Methane sulfonic acid outperforms the other acids as a strippant. Further importance was given to the stability of the liquid emulsion membrane during the extraction process. The important variables affecting the LEM permeation process of zinc in a mechanically agitated contactor (MAC), such as residence time for extraction, speed of agitation, organic diluents, surfactant concentration and internal strip acid concentration, were systematically investigated. Emulsion swelling and breakage that occurred during these investigations were also described. Finally, the static mixer (SM) device was shown to have a very good potential for LEM extraction of zinc as it outperforms MAC.     

Emulsion Liquid Membrane Pertraction of Zinc and Copper: Analysis of Emulsion Formation using Computational Fluid Dynamics

This work reports on a study of batch extraction of metal ions (copper and zinc) from dilute aqueous solutions as well as recovery of copper from electroplating waste water by the emulsion liquid membrane (ELM) technique. Several experiments were conducted to assess the effect of membrane composition on metal recovery. The effect of surfactant concentration, carrier concentration, and emulsification time on the emulsion stability has been reported. The velocity profile and flow model of the two‐phase mixing system during the preparation of the emulsion was generated using computational fluid dynamics (CFD). The batch extraction was carried out under various experimental conditions, such as agitation speed, M/E ratio, solute concentration in the feed phase, and carrier concentration in the membrane phase on the percentage recovery of zinc and copper ions in their respective feed streams. The operating parameters were optimized for maximum recovery. A comparison on the percentage recovery was made between synthetic solution and electroplating effluent containing copper ions.     

Separation of Zinc Ions from an Acidic Mine Drainage using a Stirred Transfer Cell–Type Emulsion Liquid Membrane Contactor

Abstract

This is a report on the separation and recovery of zinc ions from an acidic mine drainage using a stirred transfer cell‐type emulsion liquid membrane contactor. Di(2‐ethylhexyl) phosphoric acid was used as a highly selective carrier for the transport of zinc ions through the emulsified liquid membrane. A study was made of the effect on the extraction extent and initial extraction rate of the following variables: pH and initial metal concentration of the feed phase, carrier content in the organic solution, a stripping agent concentration in the receiving phase, and stirring speed in the transfer cell. The content of sulfuric acid as a stripping agent did not show in the studied range any significant influence on metal permeation through the SLM, although a minimum hydrogen ion concentration of 100 g/L is suggested in the internal aqueous solution to ensure an acidity gradient between both aqueous phases to promote the permeation of metal ions toward the strip liquor. Results show that using a pH of 4.0 in the feed acid solution, a concentration of 3% w/w_o of phosphoric carrier in the organic phase and a H₂SO₄ content of 100 g/L in the strip liquor, the extent and rate of extraction through the liquid membrane can be highly favored, pointing to the potential of this method for extracting heavy metals from many kinds of dilute aqueous solutions.     

Zinc and Copper Separation through an Emulsion Liquid Membrane Containing Di‐(2‐Ethylhexyl) Phosphoric Acid as a Carrier

The separation of zinc and copper ions from sulfuric acid solutions by an emulsion liquid membrane (ELM), using di‐(2‐ethylhexyl) phosphoric acid (D2EHPA) as a carrier, has been investigated. The batch extraction of zinc and copper was carried out while varying a selection of experimental conditions, i.e., stirring speed, treatment ratio, concentrations of metal ions in the feed phase, carrier and Span 80 concentration in the membrane, and internal phase concentration. The results obtained demonstrate the effectiveness of D2EHPA as a carrier for the separation of zinc and copper from sulfuric acid media using an ELM. An increase of the D2EHPA concentration beyond 2 vol.‐% does not result in the improved extraction of zinc because the viscosities of the membrane and emulsion have a trend to increase for higher carrier concentrations. It was found that the extraction rate of copper was affected by the carrier concentration in the liquid membrane and by the pH and metal content in the external phase. A 3 vol.‐% concentration of surfactant in the organic phase was required to stabilize the emulsion. The number of stages required for the extraction of zinc and copper by an ELM was determined from McCabe‐Thiele plots.     

乳状液膜提取青霉素及其溶胀的研究

采用W／O型乳状液膜提取模拟发酵液中的青霉素,考察膜相添加剂、表面活性剂、载体、解析剂Na2CO3浓度、搅拌速度对青霉素传质和液膜溶胀的影响。以span80为表面活性剂、三辛胺为流动载体、液体石蜡为膜相添加剂、煤油为膜溶剂组成的乳状液膜体系。结果表明：青霉素提取率随表面活性剂和载体浓度的增加而明显增加。但表面活性剂浓度增加使液膜易产生再乳化,而再乳化和搅拌是夹带溶胀产生的主要原因;水的渗透(渗透溶胀)随载体和内相NaCO3浓度升高而增加。液膜溶胀是影响液膜技术工业化应用的关键因素之一。适宜的液膜配方和操作条件,有利于控制液膜溶胀,增加青霉素的提取率。在本研究中,青霉素的提取率最高可达91．5％,液膜溶胀率为16％。     

乳化液膜萃取乳酸稀溶液过程中的渗透溶胀及模拟

根据膜相中载体萃取的机理,指出载体在萃取溶质后形成的络合物具有一定的亲水性．采用气相色谱法,分别对含有表面活性剂和载体的膜相在与乳酸溶液接触后的溶水率进行了测定,结果发现其溶水率远高于与无溶质的外相水接触后的膜相溶水率．所以渗透溶胀进人内相的水除表面活性剂分子结合的迁移外还有载体-溶质络合物结合水．从而提出了实际萃取过程中乳化液膜渗透溶胀的反应-溶解-扩散机理,并提出了相应的数学模型,经与实验数据比较,结果吻合较好．     

Separation of Toluene and n‐Heptane through Emulsion Liquid Membranes Containing Ag+ as Carrier

Using silver ions as carrier in oil/water/oil‐type emulsion liquid membranes, batch wise extraction experiments were carried out to separate toluene from a mixture of toluene and n‐heptane. The separation performances, represented by the permeation rate, emulsion stability, and separation factor, were analyzed systematically by varying the operating parameters, viz., contact time, concentration of Ag⁺, emulsification time, surfactant concentration, membrane stabilizer concentration, relative amount of solvent, and initial feed phase concentration. The emulsion liquid membranes thus formed are stable, and Ag⁺ and surfactant concentrations strongly affect the permeation behavior of toluene.     

Selective Separation of Gallium from Acidic Leach Solutions by Emulsion Liquid Membranes

Abstract

The separation and concentration of gallium from acidic leach solutions, containing various other ions such as iron, cobalt, nickel, zinc, cadmium, lead, copper, and aluminium, by an emulsion liquid membrane (ELM) technique using tributyl phosphate (TBP) as carrier has been presented. Liquid membrane consists of a diluent, a surfactant (ECA 4360J), and an extractant (TBP), and 0.1 M HCl or 0.1 M H₂SO₄ were used as the stripping solution. The important variables governing the permeation of gallium and their effect on the separation process have been studied. These variables were membrane type and composition, mixing speed, diluent type, surfactant concentration, extractant concentration, HCl concentration in the feed, acid type of stripping phase, feed concentration, and treatment ratio. The optimum conditions were determined. It was possible to selectively extract 96.0% of gallium from the acidic leach solutions, containing Fe, Co, Ni, Zn, Cd, Pb, Cu, and Al, at the optimum conditions.     

Emulsion liquid membrane stability in the extraction of ionized nanosilver from wash water

The discharge of ionized nanosilver into environment triggers a great concern owing to the toxicity problem for aquatic organism. In this study, emulsion liquid membrane used to extract the ionized nanosilver from wash water. Variables like carrier, stripping agent and surfactant concentrations, emulsifying time, homogenizer and agitation speed, pH feed phase, and effect of ionic liquid [BMIM]⁺[NTf₂]⁻were investigated. The membrane phase containing Cyanex 302, Span 80, acidic Thiourea, and kerosene as carrier, surfactant, stripping agent, and diluent respectively. Results demonstrated that 99.89% of silver ion was extracted and ionic liquid show good performance on emulsion stability with 10% swelling.     

乳化液膜提取柠檬酸及其溶胀的研究

本文研究了采用Ｗ／Ｏ型乳化液膜提取水溶液中的柠檬酸，同时研究了柠檬酸提取过程中水的传质行为（乳液溶胀）。考察了表面活性剂、载体、反萃剂Ｎａ２ＣＯ３、柠檬酸浓度对柠檬酸传质和乳液溶胀的影响。实验结果表明：萃取率随载体和内相试剂浓度的增加而增加；当载体和初始柠檬酸浓度较高时，乳液更易于溶胀，由此得出了除渗透压造成的乳液溶胀外，溶质与载体形成的络合物也能促成乳液的溶胀。提出了分离浓缩柠檬酸的最佳乳液配方     

Extraction of Palladium from Nitrate Medium by Emulsion Liquid Membrane Containing CYANEX 471X as Carrier

Extraction of Pd(II) from nitric acid solution with CYANEX 471X in chloroform was carried out using liquid–liquid extraction and emulsion liquid membrane (ELM) techniques. Extraction equilibrium was postulated using the slope analysis method. KSCN solution efficiently stripped Pd(II). In the ELM investigations, the effects of the different parameters affecting the membrane stability were studied. The prepared membrane was found to be selective for Pd(II) extraction in the presence of some interfering ions and its permeation reached 98%. The kinetics of Pd(II) permeation through the prepared membrane indicated that the rate of permeation depends on the carrier, Pd(II), and nitric acid concentration.     

Mathematical modeling of penicillin G Extraction by a bifunctional surfactant in a continuous extraction column

A bifunctional surfactant was used as a carrier of penicillin G for its continuous extraction by an emulsion liquid membrane without an extradant in a countercurrent extraction column of Oldshue-Rushton type. A permeation model was presented to describe transport mechanism of penicillin G in the continuous extraction system, including an axial dispersion model for the continuous phase and a mass transfer model for the dispersed emulsion phase. The mass transfer model describes the external mass transfer around the emulsion drop, the reaction at the external interface, the diffusion as well as the reaction equilibrium within the w/o emulsion drop, and the pH change of internal aqueous phase. Here, we considered three experimental variables: penicillin G concentration, pH of continuous phase and surfactant concentration. The calculated results from the permeation model fitted the experimental data well. This paper is dedicated to Dr. Youn Yong Lee on the occasion of his retirement from Korea Institute of Science and Technology.     

Efficient recovery of phenol from phenolic wastewater by emulsion liquid membrane

The recovery of phenol from phenolic wastewater by emulsion liquid membrane (ELM) was investigated. The W/O emulsion was prepared with kerosene, Span−80, carrier, liquid paraffin, and NaOH solution. The effects of NaOH concentration, oil–internal solution ratio, shearing speed, Span−80 concentration, and carrier type and concentration on emulsion breakage were studied. In the single factor experiments of stability of W/O emulsion, the lowest percentages of emulsion breakage were achieved at a NaOH concentration of 0.03 g/ml, an oil–internal solution ratio of 2:1, a shearing speed of 1500 r/min, a Span−80 concentration of 8%, a tributyl phosphate (TBP) concentration of 0.8%, and an ethyl acetate concentration of 0.8%, respectively. Then, the effects of nine factors on extraction efficiencies of phenol were investigated. This indicated that the effects of shearing speed, oil-internal solution ratio, emulsion-external solution ratio, liquid paraffin concentration, and mixing speed on extraction efficiencies of phenol were limited. However, the carrier concentration, NaOH concentration, Span−80 concentration, and phenol concentration had important impacts on the extraction efficiency of phenol. The extraction efficiency of phenol could reach 99.7%. Besides, the results of orthogonal experiments indicated that during the extraction of phenol by ELM, the order of importance of factors was NaOH concentration > emulsion-external solution ratio > volume fraction of Span−80 > volume fraction of TBP. After extraction, the recycled emulsion with Span−80 could not easily be effectively demulsified through heating, which only provided the highest demulsification efficiency of 18.2%. However, the recycled emulsion could be effectively demulsified through centrifugation, which could get the highest demulsification efficiency of 86% at a centrifugal rotational speed of 2000 r/min and a centrifugal time of 25 min.     

表面活性剂液膜萃取过程的乳液溶胀(Ⅱ)——乳液溶胀的抑制

探讨了抑制乳液溶胀的途径。着重研究了迄今尚未充分讨论的外水溶质对乳液溶胀的影响。结果证实,外水相中的电解质或葡萄糖能抑制夹带溶胀,并使渗透溶胀率降低。研究了溶剂和温度对溶胀的影响。提出了计算渗透溶胀的修正数学模型,计算值与实验值相符。     

乳状液膜法分离富集废旧镍镉电池中的镉

该文介绍了乳状液膜法分离富集废旧镍镉电池中的镉离子。乳状液膜主要由溶剂(煤油)、表面活性剂(Span80)、载体〔二(2-乙基己基)膦酸,P204〕和内水相氨水组成。对影响镉离子渗透和分离过程的重要变量进行了考察,分析了乳状液膜的载体体积分数、外水相pH、搅拌时间、乳水比(乳液与外水相体积比)及Span80体积分数对镍镉分离效果的影响,从而选择出最佳的分离条件为:φ(P204)=4.4%,φ(Span80)=8.8%,pH=5.5,乳水比0.5,搅拌时间10min。用此乳状液膜进行100L反应釜的工业放大实验,镉的迁移率可达93.3%,而镍的迁移率仅为14.6%。     

W/O/W型乳状液膜溶胀研究进展

对液膜分离技术中溶胀的分类、产生机理及近年来国内外研究进展进行了总结;针对液膜的配比和操作控制参数进行了细致深入的分析,对影响液膜溶胀的参数包括表面活性剂、流动载体、油内比、乳水比及萃取过程中搅拌时间和速度等进行了归纳,最后指出了乳状液膜技术研究的重点和方向。     

Permeation of benzene through liquid surfactant membranes

The effect of time on the permeation of benzene through aqueous surfactant membranes formed with two non-ionic surfactants has been studied on a batch scale under two different conditions of surfactant concentration and hydrocarbon: water ratio in the emulsions. The data have been correlated by an equation based on Casamatta's model of hydrocarbon permeation from an emulsion drop. The results indicate that the correlation can be used to treat the data until the onset of membrane rupture. The membrane thickness depends on the hydrocarbon: water ratio in the emulsion, and varies from about 1.57 to 5.10 μm.