Transport of cationic dye by supported liquid membrane using D2EHPA as the carrier

The transport of cationic dye from an aqueous feed solution through a flat‐type supported liquid membrane containing di‐(2‐ethylhexyl)phosphoric acid as a carrier was studied. The influence of pH on the source phase, the effect of the concentration of the receiving phase, the stirring speed, the effect of the initial dye concentration, the feed‐to‐strip ratio and the influence of the support characteristics were studied. A polytetrafluoroethylene membrane with a 1.0‐μm pore size was found to have more permeability than that with a pore size of 0.5 μm. The results indicated that the aqueous feed solution at an alkaline pH has high permeability. The initial feed phase dye can be completely extracted and stripped with a stripping solution within 7 h.     

Highly Efficient and Selective Transport of Au(III) through a Bulk Liquid Membrane using Potassium-dicyclohexyl-18-crown-6 as Carrier

Abstract

The facilitated transport of Au(III) through a chloroform bulk liquid membrane containing potassium-dicyclohexyl-18-crown-6 as a selective ion carrier was designed. Au(III) as [AuBr₄]^?, quantitatively transported across the liquid membrane. In the receiving phase, L-cysteine acts as a specific stripping agent. The amount of Au(III) transported through the liquid membrane after 120 minutes was (96.2±1.3)%. The type of halide and its concentration, pH of source and receiving phase and also the type of stripping agents were optimized. The selectivity and efficiency of gold(III) transport from aqueous solutions containing various metal ions were investigated. The presence of EDTA in the source phase diminished drastically the competitive effect of interfering metals ion.     

Highly Selective Extraction and Transport through a Bulk Liquid Membrane of L-Cysteine Using [K • DC18C6]+ Complexes

It is shown that dicyclohexyl-18-crown-6 (DC18C6) dissolved in chloroform can extract efficiently and selectively the anionic form of L-cysteine from aqueous solutions containing potassium ions. This ability depends on the aqueous phase pH and type of the salt used in this phase. Under optimized conditions L-cysteine can be quantitatively extracted into the organic phase. In such conditions there was no detectable extraction of amino acids tryptophan, tyrosine, leucine, methionine, arginine, asparagine, aspartic acid, glycine, serine, and threonine. The transport of L-cysteine from potassium chloride/potassium hydroxide solution across a bulk liquid membrane containing DC18C6 dissolved in chloroform has been investigated. The parameters influencing the transport efficiency such as the pH of the feed phase, the kind and concentration of the receiving phase, carrier concentration, the kind of organic diluents, and time were examined and optimized. An efficient stripping at the membrane/stripping phase interface was found using hydrochloric acid as strippant. Selectivity of the proposed system was evaluated by performing a series of competitive transport experiments on the binary mixtures containing L-cysteine with the competitor amino acids noted earlier. This investigation exhibits excellent transport selectivity of the process towards L-cysteine with respect to the examined amino acids.     

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.     

Use of vegetable oil in supported liquid membrane for the transport of Rhodamine B

The transport of Rhodamine B (RB) from aqueous feed solution containing sodium hydroxide through a flat supported liquid membrane (SLM) sheet containing vegetable oil as a carrier to an aqueous strip phase was investigated. The transport rate of Rhodamine B was found to increase with sodium hydroxide concentration in the feed phase. The influence of pH on the feed (source) phase, the effects of sulphuric acid concentration in the strip (receiving) phase, stirring speed, initial dye (RB) concentration and temperature were studied. Transport kinetics and stability of the membrane were also studied. Polytetrafluoroethylene (PTFE) with 1.0 µm pore size used as the membrane was found to be more permeable than that with 0.5 µm pore size. The feed solution at pH 11 ± 0.1 has the highest permeability. The initial feed solution concentration of 1.06 × 10^− 4 mol/L was completely extracted and stripped into 0.3 mol/L sulphuric acid solution in 5 h. Raising of pH in the feed solution from 7 to 13 ± 0.1 leads to an increase in dye permeation from 9.81 × 10^− 5 to 6.18 × 10^− 4 cm/s. It was observed that dye flux across the membrane tends to increase with stirring speed.     

Reverse osmosis separation of phenols in aqueous solutions using porous cellulose acetate membranes

Reverse osmosis separations of phenol (9.4 to 108 ppm), p-cresol (108 ppm), and p-chlorophenol (129 ppm) were studied using Loeb-Sourirajan-type porous cellulose acetate membranes, and single-solute aqueous feed solutions at 500 psig and the indicated solute concentrations. It was found that, by dissociating the solute by changing the pH of the feed solution, all the above phenols could be separated by reverse osmosis. Solute separation increased with increase in the degree of dissociation of the solute in the feed solution; and, by the appropriate choice of pore size on the membrane surface, separations of phenol approaching the degree of dissociation of phenol in the feed solution could be obtained under the operating conditions used. Similar experiments using aniline (93 ppm) as the solute showed that dissociation of solute molecules in the feed solution could be a technique generally applicable for the reverse osmosis separation of nonionic solutes in aqueous solution. The effects of operating pressure in the range 250 to 1500 psig and pore size on the membrane surface on the separation of un-ionized phenol and p-chlorophenol showed that, with respect to single-solute aqueous feed solutions of phenols, the component whose relative acidity was greater was preferentially sorbed at the cellulose acetate membrane—aqueous solution interface, and the solute concentration in the membrane-permeated product solution was a function of the extent and mobility of each of the sorbed species.     

Use of cyclopentyl methyl ether (CPME) as green membrane for acetic acid removal by facilitated bulk liquid membrane: A transport and kinetic study

In current investigation, cyclopentyl methyl ether (CMPE) was tested as a novel membrane solvent for acetic acid removal from an aqueous medium in the facilitated bulk liquid membrane (BLM). Tributyl phosphate (TBP) has been utilized as a carrier in CMPE to facilitate acetic acid transport. The influences of various operating factors like carrier concentration in the membrane solvent, receiving phase type, and receiving phase concentration on removal, were analyzed. The uptake was evaluated by means of feed (extraction) and receiving yields. Following this, a mass transfer modelling was established and the mass transfer coefficients were determined. The maximum yields were recorded as 95.4% for extraction and 78.01% for receiving yields at 2 mol · L⁻¹ carrier concentration in membrane solvent, and 4 mol · L⁻¹ NaOH of receiving phase concentration.     

PTFE中空纤维膜萃取对苯二胺工艺研究

以硫酸溶液为萃取剂,采用PTFE中空纤维膜萃取料液中的对苯二胺,考察了料液相对苯二胺的初始浓度、料液相初始pH、料液相与萃取相流量、萃取剂的初始浓度对对苯二胺萃取率(η)的影响。结果表明,随着料液初始浓度增大,η增大,当对苯二胺浓度0.8 g/L时,η减小,但膜通量基本不变,即存在一个最大膜通量,此时对苯二胺浓度变化对传质无影响;对苯二胺料液的pH增大,η增大;萃取相硫酸浓度增大,η增大。另外,温度升高有利于膜萃取。     

Transport of mercury(II) ion through a supported liquid membrane containing a triisobutylphosphine sulfide (Cyanex 471X) as a mobile carrier

Carrier‐facilitated transport of mercury(II) against its concentration gradient from aqueous 0.1 mol dm^?3 hydrochloric acid solution across a flat‐sheet supported liquid membrane (SLM) containing triisobutylphosphine sulfide (Cyanex 471X) as the mobile carrier in kerosene as diluent has been investigated. Dilute sodium thiocyanate solution (0.11 mol dm^?3) was the most efficient stripping agent among several aqueous reagents tested. Various parameters such as stirring rate, concentration of HCl in the feed solution, concentration of NaSCN in the strippant, concentration of Cyanex 471X in the membrane, and contact time were investigated. Under optimum conditions the transport of Hg(II) across the liquid membrane is about 100% after 6 h. The carrier, Cyanex 471X, selectively and efficiently transported Hg(II) ions in the presence of other associated metal ions. The method has been demonstrated to recover selectively mercury from waste samples and mercurochrome solution. © 2002 Society of Chemical Industry     

Stability of a Supported Liquid Membrane for Removing Hydrophobic Solutes from Casein Hydrolysate Solution

Abstract

The stability of a liquid membrane containing a solution of an ionic carrier (Aerosol OT, AOT) in oleyl alcohol and loaded on a commercial support, Celgard 2500, was examined. The experiments were conducted in this flat-sheet support to continuously remove hydrophobic solutes from a feed of casein hydrolysate solution with a strip solution of sodium chloride. Three approaches were investigated to study flux stability of the membrane; i.e., by 1) varying AOT concentrations (10–40% w/w), 2) using a different solvent (decanol instead of oleyl alcohol), and 3) applying an interfacial surface layer on the membrane support. At higher AOT concentrations the flux through the membrane was stable up to 40 hours; the flux declined rapidly beyond this period to about half the initial value and slowly decreased to low values after 120 hours. The use of decanol (100% pure) instead of oleyl alcohol (85% pure) as the membrane solvent increased the flux and improved the stability without significant loss of performance up to about 70 hours. The application of an interfacial gel layer at the feed, strip, or both interfaces did not improve the stability of the AOT/oleyl alcohol membrane. The generation of a polymerized layer at the interface between the organic and aqueous phases of the membrane showed better stability. However, the solute flux through the polymerized membrane was reduced to a low value.     

Response Surface Optimization of Dysprosium Extraction Using an Emulsion Liquid Membrane Integrated with Multi‐Walled Carbon Nanotubes

A new emulsion liquid membrane was prepared for dysprosium (Dy) extraction from aqueous solution using multi‐walled carbon nanotubes (MWCNTs). The influence of MWCNT concentration, carrier and surfactant concentration, stirring speed, feed‐phase pH, and internal phase concentration and their interactive effects were studied. A regression model for Dy extraction was developed and the parameters were optimized by response surface methodology. The extent of extraction increases with higher MWCNT concentration up to a certain level. The Dy extraction through the liquid membrane containing MWCNT improves with time. Moreover, the overall mass transfer coefficient was enhanced in the presence of MWCNT due to the formation of a more stable emulsion and liquid membrane.     

Selective Transport of Cu2+ Ions through Bulk Liquid Membrane System Mediated by Erythromycin Ethyl Succinate

The carrier mediated transport of Cu²⁺ ions from an aqueous medium has been examined. The ability of Erythromycin Ethyl Succinate (EES) as a carrier to form a complex with Cu²⁺ ions and transport them to the receiving phase is reported. The fundamental parameters influencing the transport of Cu²⁺ ions such as the pH in the source and receiving phases and concentration of the stripping agent in the receiving phase have been optimized and accordingly, the amount of Cu²⁺ transported across the liquid membrane after 5 h was 94.3 ± 1.8% in the presence of L-histidine as a suitable stripping agent. Moreover, the selectivity and efficiency of Cu²⁺ ions transport from aqueous solution over other cations in ternary and quaternary mixtures have been investigated. The results indicate that our fabricated membrane is very sensitive toward Cu⁺² ions in the presence of heavy metal ions.     

PTFE中空纤维膜萃取苯甲酸工艺研究

以氢氧化钠溶液为萃取剂,采用PTFE中空纤维膜萃取料液中的苯甲酸,考察了料液相苯甲酸的初始浓度、料液相初始pH、料液相与萃取相流量比、萃取剂的初始浓度对苯甲酸萃取率(η)的影响。结果表明,随着料液初始浓度增大,η增大,当苯甲酸浓度1 g/L时,η减小,但膜通量基本不变,即存在一个最大膜通量,此时苯甲酸浓度变化对传质无影响;料液的pH值下降,η增大;萃取相氢氧化钠浓度增大,η增大;存在一个最佳相流量比(Q料/Q萃)为1.8。另外,温度升高有利于膜萃取。     

液膜法分离富集对氨基酚

引　言对氨基酚 (PAP)含有两性官能团 ,有独特的物理、化学和生物性质 ,是一种应用广泛的精细化工中间体 .PAP是一种毒性较强的物质 ,难以自然降解[1] ,并在食物链中形成积累 .因此 ,将含PAP的废水进行处理 ,对于保护环境具有重要的实际意义 .含PAP的废水可生化性很差 ,且一般的混凝法和化学氧化法均难以达到较好的处理效果 .乳状液膜法在用于分离某些物质时具有快速、高效、选择性好的特点 ,尤其是对低浓度物质的分离富集更具优势 .该方法已被应用于湿法冶金[2 ] 、医药化工[3] 和环境保护[4 ] 等研究领域 .因此 ,若将乳状液膜法用于…     

中空纤维更新液膜在己内酰胺精制中的应用

研究了中空纤维更新液膜技术用于己内酰胺精制时的传质性能,考察了两相流速、萃取剂用量对传质的影响,并与大块液膜技术以及萃取塔技术进行了对比。在实验范围内,中空纤维更新液膜过程总传质系数随两相流速的增大而增大,且壳程流速对传质的影响较大。中空纤维更新液膜过程传质通量可达大块液膜的1．5倍,总体积传质系数可达工业萃取塔的2．3倍,萃取剂用量相比于大块液膜、工业萃取塔大幅度降低,具有很大的应用潜力。     

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.     

PTFE中空纤维膜萃取烟酸工艺研究

以氢氧化钠溶液为萃取剂,采用PTFE中空纤维膜萃取料液中的烟酸,考察了料液相烟酸的初始浓度、料液相初始pH值、料液相与萃取相流量比、萃取剂的初始浓度对烟酸萃取率(η)的影响。结果表明,随着料液初始浓度增大,η增大,当烟酸浓度0.9 g/L时,η减小,但膜通量基本不变,即存在一个最大膜通量,此时烟酸浓度变化对传质无影响;烟酸料液存在一个最佳pH值为4~5;萃取相氢氧化钠浓度增大,η增大;存在一个最佳相流量比(Q料/Q萃)为2.1;温度升高有利于膜萃取。     

Use of bulk liquid membrane for the removal of chromium (VI) from aqueous acidic solution with tri-n-butyl phosphate as a carrier

Tri-n-butyl phosphate (TBP) was used as carrier for the transport of chromium (VI) through a hexane bulk liquid membrane. The transport efficiency of chromium (VI) by TBP was investigated under various experimental conditions such as pH of the feed phase (Cr (VI) solution), concentration of the receiving phase (NaOH solution), concentration of TBP in membrane, rate of stirring, effect of transport time, type of solvent, Cr (VI) concentration in feed phase, and effect of temperature. The transport efficiency increased with increasing carrier concentration from 7.5 × 10^− 2 to 2.25 × 10^− 1 mol/L. At high pH (donor phase) the transport rate of chromate ions decreased. At high stirring speed (300 rpm) the Cr (VI) transport from the feed phase to the strip phase was completed within 5 h at 27 °C. Under optimum conditions: donor phase 4.8 × 10^− 4 mol/L K₂Cr₂O₇ solution at pH 1.0 ± 0.1, acceptor phase 1.0 mol/L NaOH solution, membrane phase 2.25 × 10^− 1 mol/L, stirring speed 300 rpm, and temperature 27 °C, the flux rate was found to be 2.90 × 10^− 7 mol/m² s.     

Separation of l-valine by anionic carrier-mediated transport in a supported liquid membrane

An anionic carrier-mediated separation of L-valine from the dilute aqueous solution was studied with a liquid membrane, constituted by a solution of D2EHPA (Di-2-Ethyl Hexyl Phosphoric Acid) in 1-decanol and supported by a hydrophobic microporous membrane. The equilibrium and transport rate data are reported in terms of distribution coefficients and mass transfer coefficients under the varying conditions of feed phase pH and carrier concentration. The experimental results obtained are analyzed to confirm the mechanism of the complex formation between carrier and L-valine and to describe the transport rate of L-valine through the supported liquid membrane by an appropriate theoretical model. The selectivity and the stability of the supported liquid membrane under study were also evaluated to ensure its potential application as a commercial down-stream process.     

Emulsion liquid membrane pertraction of L-lysine from dilute aqueous solutions by D2EHPA mobile carrier

The results of experimental studies on the batch extraction of L-lysine by emulsion liquid membrane are discussed and the capabilities of this method in the separation of solute from dilute aqueous solutions are shown. Studies on the extraction equilibrium for organic and aqueous phases were performed. The experimental results showed that the degree of extraction was increased by an increase in the pH of the feed phase, the concentration of [H⁺] in the internal phase, and concentration of the carrier in the organic phase. An optimum value of stirring speed was achieved. The rate of water swelling as an undesirable phenomenon was also measured.