支撑液膜萃取乳酸传质模型

本文对使用支撑液膜(Supported Liquid Membrane)从水溶液中革取乳酸(HL)的过程进行了理论分析,经过适当的简化,推导出支撑液膜革取乳酸的传质模型。对模型进行了实验验证,测得了膜的弯曲因子及过程的促进因子,模型计算值与实验值相吻合,同时得出膜内载体三烷基氧磷(TRPO)与乳酸形成的萃合物分子式为HL·TRPO。     

乳酸的乳化液膜萃取与有机溶剂萃取的比较

在乳酸发酵与分离耦合过程中,可以采用乳化液膜萃取法或有机溶剂萃取法提取发酵液中的乳酸。本文比较了这两种方法的传质机理和操作过程,并实验分别研究了它们的最佳工艺条件,提出：在最佳操作条件下,提取相同量的乳酸,有机溶剂萃取有机相的消耗量为乳化液膜法的３－４倍,乳化液膜法萃取率高,而且能得到浓缩的乳酸。     

Enzyme Separation Using Supported Liquid Membrane Filled with Reversed Micelles

Abstract

A phenomenological model describing the transfer of lysozyme between a bulk aqueous phase and a reversed micellar phase in a stirred membrane cell has been confirmed. Transport of the enzyme at the interface at low surfactant concentrations is dominant, while that through the membrane is the rate-determining step at high surfactant concentrations. Complete separation of α-chymotrypsin from lysozyme using a supported liquid membrane filled with reversed micelles demonstrates the feasibility of the present process for enzyme separation.     

液膜技术在有机废水处理中的应用

综述了液膜分离的原理及该技术在有机废水处理领域中的研究进展和应用实例。     

Transport of lithium through a supported liquid membrane of LIX54 and TOPO in kerosene

A mathematical transport model is developed for the extraction of lithium from dilute synthetic solution, simulating geothermal water, using a supported liquid membrane (SLM) of LIX54 (major component is -acetyl-m-dodecylacetophenone) and TOPO (tri-n-octylphosphine oxide) in kerosene. The model is based on fundamental mass transfer and kinetics mechanisms that account for all possible transport resistances. The model is solved numerically and is used to investigate the effect of various extraction conditions and membrane support characteristics. Reasonable agreement is found between the predicted and the experimental results reported in literature.     

Transport Behavior of Basic Amino Acids through an Organic Liquid Membrane System

Abstract

The transport behavior of basic amino acids (BAA), such as arginine (Arg), histidine (His), and ornithine (Orn), through an organic liquid membrane system (LMS) was investigated. The LMS was composed of two aqueous phases (Phases I and II) separated by an organic phase of chloroform containing sodium di-(2-ethylhexyl) sulfosuccinate (Aerosol OT, AOT). The amount of BAA that moved from Phase I at pH 3 into the organic phase increased with increasing AOT concentration (2–10 mM). The relative amount of extracted BAA was in the following order: Arg > His > Orn. On the other hand, the release of BAA from the organic phase into Phase II at pH 10 did not depend upon their amount in the organic phase. Arg was difficult to release. The relative amount of released BAA was in the following order: Arg = His > Orn. BAA were extracted from Phase I at pH 5 into the organic phase containing 4 mM AOT because they exist as cationic species. Other amino acids possessing nonionic residues were untransportable under these conditions except leucine, tryptophan, and phenylalanin, which have highly hydrophobic residues. However, they were transportable in their cationic forms at pH 1. These transport phenomena are essentially controlled by the interaction of the anionic group of AOT and a cationic form. These results suggested that BAA can be separated from most amino acids under an appropriate pH by using AOT.     

苯酚体系支撑液膜不稳定性研究

The instability mechanisms of the supported liquid membrane using Celgard 2500 membranes as support and tributyl phosphate dissolved in kerosene as carrier for phenol transport was studied by electrochemical impedance spectroscopy. Emulsion formation is demonstrated to be one of the main causes for the instability of supported liquid membrane in the present system. The emulsion-facilitated conditions, such as higher membrane liquid concentration, faster stirring speed, lower salt concentration and higher HLB value, would accelerate the degradation of supported liquid membrane. Other mechanisms including solubility and os-motic pressure work together to increase the membrane liquid loss.     

Extraction of Amino-J Acid from Waste-water by Emulsion Liquid Membrane

The emulsion liquid membrane technique was used to extract amino-J acid from industrial dye waste-water. The effects of stirring speed, ratio of the emulsion to water (Rew), ratio of the oil to internal phase (Roi) and membrane phase components on the extraction rate were investigated and optimized. The results showed that the extraction rate of amino-J acid approached 97% when the stirring speed was 300 r/min, Rew 1:6, Roi 1:1, trioctylamine (TOA) 3 mL/100 mL kerosene, and methyl-didecyle-alcohol-acrylate (LMA-2) 3 g/100 mL kerosene, respectively. The extraction rate had not changed with the oil phase reused for times.     

Selective Transport of Alkali and Alkaline Earth Metallic Ions through a Supported Liquid Membrane Containing Tripentyl Phosphate as a Carrier

Abstract

A selective transport system for alkali and alkaline earth metallic ions with a perchlorate ion as a pairing ion species through a supported liquid membrane (SLM) containing tripentyl phosphate (TPP) as a carrier is described. The SLM used is a porous polypropylene membrane impregnated with TPP solution in o-nitrophenyloctylether. The effects of the pairing ion species, the initial perchlorate concentration, and the TPP concentration on metallic ion transportability are examined under various experimental conditions. The permeation velocities of the metallic ions in the transport system followed the sequence Li⁺?Na⁺>K⁺>Mg²⁺; that is, a highly selective transport for Li⁺ ion was observed. Compared with the transport rates of alkali metallic ions, those of transition metallic ions such as Cu²⁺ and Fe³⁺ ions are very low. The permeation velocities of alkali and alkaline earth metallic ions through an SLM are dependent on the concentrations of perchlorate and TPP. Equations for the permeation velocities of Li⁺, Na⁺, K⁺, and Mg²⁺ ions through an SLM, based on two concentrations of perchlorate and TPP, are proposed.     

The Transport of Copper(II) through Hollow Fiber Renewal Liquid Membrane and Hollow Fiber Supported Liquid Membrane

Abstract

In this paper, hollow fiber renewal liquid membrane (HFRLM) and hollow fiber supported liquid membrane (HFSLM) were used to simultaneously remove and recover copper(II) from aqueous solutions, and the transport performance of these two techniques were compared under the similar conditions for the system of CuSO₄ +D2EHPA in kerosene +HCl. The results showed that the HFRLM process was more stable than the HFSLM process. The HFRLM process had a higher overall mass transfer coefficient than that of HFSLM process in single-pass experiments. These were because the renewal effect of the liquid membrane layer could reduce the mass transfer resistance of the lumen side and replenish the loss of the membrane liquid in the HFRLM process. The transport results were better in the HFRLM process than that in the HFSLM process with recycling experiments. Therefore, HFRLM technique is a promising method for simultaneous removal and recovery of heavy metal from aqueous solutions.     

Modeling of Thallium Extraction in a Hollow-Fiber Membrane Contactor

A mass transfer model was developed to simulate the solvent extraction of thallium by butyl acetate through a hollow-fiber membrane contactor. The model was based on the solving conservation equations including mass and momentum transfers for thallium in both aqueous and solvent phases as well as membrane. The model equations were solved by a numerical method based on the finite element method. The simulations were conducted using experimental data obtained from literature for two different modules consisting of hydrophobic polypropylene (PP) and polyvinylidene fluoride (PVDF) fibers. The fibers had different effective membrane areas. The model findings were then verified through comparison with experimental data. The comparison showed an average deviation of 9% with the experimental data. The effect of process variables on thallium mass transfer was investigated. The results confirmed that the developed model predicts well the general behavior of thallium extraction versus process variables.     

Study on Competitive Transport of Heavy Metal Ions Through Liquid Surfactant Membrane

Abstract

In the present work an attempt has been made to develop a mathematical model for competitive transport of Cr(VI) and Mo(VI) through liquid surfactant membrane from acidic solution using Alamine‐336 and Caustic Soda as extractant and stripping reagent respectively. A reaction front has been assumed to exist within the emulsion globule in the proposed model. It has been assumed that, an instantaneous and irreversible reaction takes place at the membrane‐internal stripping phase interface between the solute and internal stripping reagent. Experiments on simultaneous extraction of Cr(VI) and Mo(VI), in batch mode, from aqueous solutions of Potassium Dichromate and Ammonium Molybdate have been carried out with the initial concentration of the solutes between 50–100 mg/l. Experiment on emulsion stability has also been performed to arrive at a reasonably stable emulsion composition. Effect of initial solute concentration on distribution coefficient has also been found experimentally and fitted by a semiemperical model that has been used in the computer simulation of the simultaneous extraction process. It has been found that the experimental results are within reasonably close proximity with the simulated curves.     

乳状液膜分离Zn^2＋的界面传质阻力及传质模型

用Ｌｗｅｉｓ恒界面传质池对乳状液膜分离Ｚｎ＾２＋的传质阻力进行实验研究，结果表明由于表面活性剂单分子层的形成，使界面传质阻力占整个传质阻力的８５％。在此基础上所建立的既考虑界面传质阻力又考虑膜破碎的液膜传质模型能使用理论计算值与实验测定值符合较好。     

Selective Separation of Toluene/n‐Heptane by Supported Ionic Liquid Membranes with [Bmim][BF4]

Room‐temperature ionic liquids serve as alternative solvents for volatile organic compounds in liquid‐liquid extraction and liquid membrane separation. 1‐Butyl‐3‐methylimidazolium tetrafluoroborate ([Bmim][BF₄]) was applied for extraction and supported ionic liquid membranes (SILMs) to separate toluene and n‐heptane. A high separation factor of toluene was achieved due to the strong interaction between ionic liquid cations and toluene. The mass transfer performance of the SILM process was enhanced by higher operating temperature. With the increase of initial toluene concentration in the feed phase, the mass transfer flux and removal efficiency of the SILM process were improved, while the separation factor decreased. The mass transfer flux was growing with the increase of flow rate at both sides. The SILM process was stable over a long time period due to the high viscosity and low volatility of [Bmim][BF₄].     

Separation of Propylene-Propane Mixture Using Immobilized Liquid Membrane via Facilitated Transport Mechanism

Abstract

Separation of propylene-propane mixtures using immobilized liquid membrane was investigated. A porous polymeric sheet was used as support to immobilize the liquid membrane. The effect of propylene partial pressure in feed stream, trans-membrane pressure, and carrier concentration on membrane separation performance was investigated and the results were evaluated in terms of separation factor, propylene permeability, and propane permeability. Propylene permeability ranged from 0.4 to 650 Barrer. Moreover, it was observed that for 30:70 (vol.%) propylene-propane mixture, at pressure 120 kPa and carrier concentration 20 wt.%, a separation factor of 480 was obtained.     

Mass Transfer Investigation of Liquid Membrane Transport of Gold (III) by Methyl Isobutyl Ketone Mobile Carrier

Extraction of Au^III ions by an emulsion liquid membrane (ELM) system with methyl isobutyl ketone (MIBK) as the mobile carrier and also liquid‐liquid extraction of Au^III from aqueous solutions have been studied. Experiments on the transport of the gold ions in a liquid‐liquid extraction system and stripping of the extracted ions from the organic phase as well as the extraction by a three‐phase W/O/W emulsion liquid membrane system have been performed. The results showed that even when the distribution coefficient of the diffusing species in the phases is small, the extraction by emulsion liquid membranes would be an effective process. A first‐order extraction rate was proposed and examined for the extraction system.     

中空纤维更新液膜传质性能的研究

研究了中空纤维更新液膜(HFRLM)技术的传质性能.以CuCl2水溶液-10%P204 煤油-盐酸为实验体系,研究结果表明,中空纤维更新液膜技术可以实现同级萃取-反萃,且总传质系数随料液相流速的增大而增大,在实验条件下,总传质系数受反萃相流速的影响较小.实验研究探讨了混合方式(料液与萃取剂混合和反萃剂与萃取剂混合)和体系分配系数对传质性能的影响.实验结果表明,由于相间分配系数的不同,总传质系数受混合方式的影响较大,以分配系数较大的一相与萃取相混合流经管程的方式对传质过程有利.     

液膜法提取绿原酸的实验研究

采用液膜法提取杜仲叶中绿原酸,通过正交实验对液膜制备工艺和绿原酸提取工艺进行了研究。结果表明,液膜制备的最佳工艺条件为:NaOH浓度4mol.L-1、吐温-20质量分数8%、搅拌速度350r.min-1;绿原酸提取的最佳工艺条件为:混合时间8min、乳水比1∶2、搅拌速度100r.min-1、油内比3∶1。液膜法实现了对绿原酸的提取和浓缩,为进一步开发利用绿原酸提供了依据。     

两相更新支撑液膜中金属二价镍的迁移行为研究(英文)

A novel disphase supplying supported liquid membrane(DSSLM),containing supplying feed phase and supplying stripping phase for transport behavior of Ni(II),have been studied.The supplying supported feed phase included feed solution and di(2-ethyhexyl) phosphoric acid(HDEHP) as the carrier in kerosene,and supplying stripping phase included HDEHP as the carrier in kerosene and HCl as the stripping agent.The effects of volume ratio of membrane solution to feed solution(O/F),pH,initial concentration of Ni(II) and ionic strength in the feed solution,volume ratio of membrane solution to stripping solution(O/S),concentration of H2SO4 solution,HDEHP concentration in the supplying stripping phase on transport of Ni(II),the advantages of DSSLM compared to the traditional supported liquid membrane(SLM),the system stability,the reuse of membrane solution and the reten-tion of membrane phase were studied.Experimental results indicated that the optimum transport of Ni(II) was ob-tained when H2SO4 concentration was 2.00 mol·L-1,HDEHP concentration was 0.120 mol·L-1,and O/S was 4:1 in the supplying stripping phase,O/F was 1︰10 and pH was 5.20 in the supplying feed phase.The ionic strength in supplying feed phase had no obvious effect on transport of Ni(II).When initial Ni(II) concentration was 2.00×10?4 mol/L,the transport percentage of Ni(II) was up to 93.1 % in 250 min.The kinetic equation was deduced in terms of the law of mass diffusion and the interface chemistry.