胶团强化超滤在处理重金属离子废水中的应用

本文介绍了一种具有表面活性荆双分子结构特性的新型重金属离子废水处理技术一胶团强化超滤（Micellar—enhanced Ultrafiltration,简称MEUF）。MEUF适用于单独或同时从废水中去除多价金属离子,具有工艺简单,易于工业化的特点。文章介绍了胶团强化超滤的原理、主要影响因素、存在的问题及解决方法,总结了近年来胶团强化超滤应用的最新研究成果,认为该技术具有良好的应用前景。     

处理含有机污染物废水的新万法--胶团强化超滤

胶团强化超滤是一种处理含有机污染物废水的新技术。该技术利用表面活性剂胶团对有机物的增溶作用,结合超滤工艺,进而达到去除有机污染物的目的。文章详细介绍了胶团强化超滤处理含有机污染物废水的原理、影响因素,分析了该技术目前存在的问题以及今后的发展方向。     

胶团强化超滤技术在染料废水处理中的应用研究进展

胶团强化超滤技术(MEUF)的研究开发,使得采用投资、运行费用都相对较低的超滤膜分离工艺能高效去除废水中的低浓度染料分子和有机物从理论和技术上成为可能.综合分析了胶团强化超滤技术的原理,以及应用于染料废水处理的主要影响因素,同时指出了该技术应用中存在的问题.     

胶团强化超滤对二氯乙烷的分离作用及浓缩液后处理

本文利用聚丙烯腈中空纤维膜组件,根据胶团强化超滤法,以十六烷基三甲基溴化铵（CTAB）为增溶剂,对模拟聚乙烯生产废水中的1,2-二氯乙烷（DCE）进行分离实验。确定了最佳表面活性剂投加量、超滤操作条件及浓缩液后处理方法,并得到较高的DCE去除率。     

胶团强化超滤去除水中硝酸盐氮的实验研究

以表面活性剂CTAC和CPC为吸附载体,研究了胶团强化超滤(MEUF)对低浓度硝酸盐氮的截留效果。研究结果表明,以CTAC为表面活性剂进行胶团强化超滤时其对硝酸盐氮的截留率较CPC为表面活性剂时要高。当静置时间为10 min、pH=7、CTAC投加量为1.5倍CMC时,对硝酸盐氮的截留率最高,为97.33%,表明MEUF在低浓度硝酸盐氮废水处理中具有良好的应用前景。     

膜技术在废水处理中的应用

本文介绍了膜技术处理废水的基本原理及其特点，综述了反渗透、微滤、超滤、液膜和电渗析等传统膜技术在废水处理的应用，以及纳滤膜、充气膜、膜生物反应器、渗透蒸发和胶团强化超滤法等新型膜技术在废水处理的发展及其应用，指出了膜技术在处理废水中存在的主要问题，并对膜技术处理废水的发展前景作了展望。     

MEUF去除废水中重金属和有机物及其浓缩液的处理

胶团强化超滤(MEUF)是一种表面活性剂和超滤相结合的处理含重金属或有机污染物废水的新技术。详细介绍了MEUF技术的原理、表面活性剂的选择、影响处理效果的主要因素,同时针对MEUF技术目前存在的浓缩液处理和表面活性剂回收的问题作了详细的阐述,综述了近年来MEUF技术应用的最新研究成果,并就此技术存在的问题和发展前景作了相关分析,实践表明该技术具有很好的应用前景。     

一些阴离子／阳离子二元混合体系的增溶行为

研究了十二烷基聚氧乙烯（约含3个EO基团）硫酸三乙醇铵（TADPS）分别与十六烷基三甲基溴化铵（CTABr）、氯化十六烷基毗院（CPCI）以及氯化十二烷基吡啶（DPCI）的二元混合体系对正庚烷、正辛醇以及甲苯的饱和增溶行为。结果表明,混合体系在增溶方面的协同效应取决于增港物的极性或增港物在胶团中的位置．对增溶于胶团内核的非极性正庚烷,TAPDS／CTABr体系显示出较强的实际正协同效应,最大添加浓度（MAC）可用Nishikido的阴离子-阳离子复合物理想增港模型来预测;对既可增溶于胶团的内核,又可增溶于胶团栅栏中的微极性的甲苯,三个混合体系皆表现出实际的正协同效应;但对增溶于胶团栅栏,与表面活性剂形成混合胶团的两亲物质正辛醇,TAD－PA／CTABr体系显示出负协同效应,并且增溶物在胶团相和水相中的分布系数符合Treiner的非理想增溶模型。这些结果表明,阴离子／阳离子混合体系在胶团强化超滤（MEUF）技术中具有潜在的应用前景。     

利用低浓度表面活性剂胶团强化超滤处理含锌废水

利用低浓度的阴离子表面活性剂十二烷基硫酸钠（SDS）,对含Zn^2＋废水进行了胶团强化超滤（MEUF）研究．结果表明：进料液的静置时间为3h时,Zn^2＋在SDS胶团上的吸附达到平衡状态。当Zn^2＋的浓度一定时,由于发生在膜表面的浓差极化现象的影响,在进料液中投加浓度低于1倍临界胶束浓度（CMC）的SDS,不但在很大程度上降低了SDS的用量,而且亦可获得较高的Zn^2＋截留率和渗透通量,Zn^2＋的截留率主要受膜表面SDS浓度的影响。随着进料液中SDS浓度的升高,渗透通量逐渐降低,而渗透液中SDS的浓度随之不断增大,但无论进料液中SDS浓度有多大,渗透液中SDS的浓度都不会高于1倍CMC（2．25g／L）,所以渗透液中的SDS的损失相对较小。Zn^2＋截留率随进料液中Zn^2＋浓度逐步增大而逐渐减小,基于低浓度表面活性剂的胶团强化超滤技术适宜处理低浓度含Zn^2＋废水．     

超声波强化超滤的研究进展

本文综述了超声波强化超滤的作用机理，声冲流和空化作用在超声波强化超滤中起到主要作用。文章还综述了超声波强化超滤的实验方法、超声波辐射对超滤膜的影响及超声波强化清洗超滤膜等方面的研究进展。     

Concentration Polarization Effects in the Use of Micellar-Enhanced Ultrafiltration to Remove Dissolved Organic Pollutants from Wastewater

Abstract

Micellar-enhanced ultrafiltration (MEUF) is used to remove 4-tert-butylphenol (TBP) from aqueous solution, a separation for which traditional ultrafiltration is ineffactive. A micelle—forming surfactant is added to the solution. The micelles solubilize a high fraction of the TBP. The stream is then forced through an ultrafilter. Overall rejection of TBP was greater than 99%. under all conditions studied and did not decrease with increasing pressure drop. Micelles were completely rejected by membranes with pore size 10 000 Dalton MWCO and below. Concentration polarization affects MEUF fluxes under conditions of interest. Bel polarization theory does not completely explain MEUF flux behavior. Selection of optimum operating parameters in MEUF application are discussed.     

基于胶束强化超滤的金属离子去除技术研究进展

胶束强化超滤技术(MEUF)作为一种新兴的含金属废水处理技术,有着较好的应用前景.通过总结前人的研究结果,综合讨论了影响金属离子截留效果的各个因素,为优化MEUF提出了一些建议.并就当前采用胶束强化超滤法处理金属离子技术的最新发展与表面活性剂的循环再利用作了简要的介绍.     

Solubilization and micellarenhanced ultrafiltration ofo-cresol by Sodium Dodecyl Sulfate Micelles

The solubilization and the micellar-enhanced ultrafiltration (MEUF) of o-cresol were investigated by using an anionic surfactant, sodium dodecyl sulfate (SDS). In order to study the solubilization behaviour of the solute, the semiequilibrium dialysis (SED) method was employed and stirred-cell ultrafiltration experiments were performed for the test of MEUF. The analysis of the results supported that approximately two surfactant molecules provide a location for the solubilized solute within micelle. In the removal of o-cresol by MEUF, as long as high SDS concentrations in the retentate (>0.2 M) are avoided, relatively good rejection of o-cresol (85 %) could be obtained under the conditions used (initial concentration ratio:[o-cresol]/[SDS]=0.2 and 0.6). Furthermore, the ultrafiltration processes were nearly at equilibrium, so that the permeate concentrations of o-cresol could be predicted from the SED results. The separation efficiency was greater at lower o-cresol concentrations when the SDS concentrations were fixed in the feed, while the rejection increased with increasing the SDS concentrations at constant intramicellar mole fraction of the solute Xc. In addition, as the o-cresol loading of retentate increased, the less SDS in the retentate permeated through ultrafiltration membranes. On the other hand, the higher o-cresol loadings reduced the fluxes of MEUF runs.     

Micellar Enhanced Ultrafiltration as a Method of Removal of Chromium(III) Ions from Aqueous Solutions

This study was undertaken to check the possibility of using micellar enhanced ultrafiltration (MEUF) in the removal of chromium(III) ions from water systems. The influence of ion concentration in the feed, type of surfactant (SDS or Rofam 10), and the membrane material on separation efficiency were studied and discussed. The use of environmentally safer surfactants from renewable sources was proposed, that is, oxyethylated rape fatty acid methyl esters – trade name: Rofam 10. The results presented show the possibility of using MEUF as an effective method for removing chromium(III) ions from aqueous solutions, especially from solutions of low concentration.     

Removal of Divalent Metal Cations and Their Mixtures from Aqueous Streams Using Micellar-Enhanced Ultrafiltration

ABSTRACT

Micellar-enhanced ultrafiltration (MEUF) is a novel membrane-based separation technique that can be used to remove multivalent metal cations from aqueous streams. In this technique an anionic surfactant is added to the aqueous stream containing the metal cations to be removed. The surfactant forms highly charged aggregates called micelles onto which the metal cations adsorb or bind. The aqueous stream is then passed through an ultrafiltration membrane with pores small enough to block the passage of the micelles and adsorbed metal cations. In this study, MEUF has been shown to remove divalent cadmium, zinc, copper, and calcium ions and their mixtures with rejections of at least 96%. A previously developed equilibrium binding model describes the results successfully. Under reasonable conditions the flux rates are not substantially below that of pure water, indicating the feasibility of MEUF for industrial application.     

Removal of Ni(II) ions from wastewater by micellar enhanced ultrafiltration using mixed surfactants

Ni(II) ions were removed from aqueous waste using micellar enhanced ultrafiltration (MEUF) with a mixture of surfactants. The surfactant mixture was the nonionic surfactant Tween 80 (TW80) mixed with the anionic surfactant sodium dodecyl sulfate (SDS) in different molar ratios ranging from 0.1–1.5. The operational variables of the MEUF process such as pH, applied pressure, surfactant to metal ion ratio and nonionic to ionic surfactant molar ratio (α) were evaluated. Rejection of Ni and TW80 was 99% and 98% respectively whereas that for SDS was 65%. The flux and all resistances (fouling resistance, resistance due to concentration polarization) were measured and calculated for entire range of α respectively. A calculated flux was found to be declined with time, which was mainly attributed to concentration polarization rather than resistance from membrane fouling.     

Partition Coefficients for Continuous Micellar Reaction Processes

The micelle‐water partition coefficients of reactants, products, and catalyst ligands are predicted using UNIFAC‐IF and COSMO‐RS. It is demonstrated that both models represent a reasonable tool for preliminary screening of the micellar systems for a specific continuous reaction process supported by micellar enhanced ultrafiltration (MEUF). The model reaction is the hydrogenation of itaconic acid and its derivatives (dialkyl esters) in the presence of a rhodium‐based catalyst. The effect of the size and nature of the surfactant head group and tail is explored for nonionic and ionic surfactants. The high partition coefficients of the catalyst ligands indicate that no catalyst leakage is expected in MEUF. Based on the concentration dependence of the calculated partition coefficients, the solubilization capacity of micelles is estimated.     

胶团强化超滤法处理废水中二氯乙烷的研究

本研究工作分两部分：增溶和超滤。首先,用正交实验的方法研究阴、阳、非离子三种不同类型的表面活性剂增溶废永中的二氯乙烷以确定最佳表面活性剂种类、投加浓度、增溶振荡时间和平衡静置时间。正交实验结果表明：表面活性剂浓度越高,对二氯乙烷的去除率也越高;实验所选的三种表面活性剂对二氯乙烷的去除率由高到低的顺序依次为：非离子、阳离子、阴离子表面活性剂;表面活性剂种类和投加浓度对二氯乙烷的去除率影响最大,振荡时间其次,静置时间影响最小。其次,用不同截留分子量的超痣膜超滤测得胶团强化超滤法对二氯乙烷去除率在60％～90％。     

Use of Micellar-Enhanced Ultrafiltration to Remove Dissolved Organics from Aqueous Streams

Abstract

Traditional ultrafiltration is ineffective at removing dissolved low molecular weight organics from water. In micellar-enhanced ultrafiltration (MEUF), surfactant is added to the water at concentrations well above the critical micelle concentration. Almost all of the organic originally dissolved (the solute) solubilizes in the micelles formed by the surfactant. The solution then passes through an ultrafiltration membrane with pores small enough to block micelle passage. The permeate contains (at most) only the unsolubilized solute and the surfactant monomer, both at very low concentrations. In this work, the criteria for selecting a surfactant are considered and MEUF is tested on an aqueous stream containing 4-tert-butyl-phenol with hexadecylpyridinium chloride as the surfactant. At high surfactant concentrations (0.25 M) in the retentate, rejections decrease, probably owing to the formation of n-mers (e.g., dimers, trimers, etc.) which are able to pass through the pores along with some solubilized solute. Also under these conditions, the viscosity increases while fluxes decline sharply. So long as these high surfactant concentrations are avoided, MEUF is an extremely effective separation technique, resulting in an average solute rejection of 99.7%, a permeate/feed ratio of 87%, and good fluxes under the conditions studied.