乳状液膜系统稳定性的显微研究及Cr(Ⅵ )离子分离效率分析

采用毛细显微摄像技术,对乳状液膜系统的稳定性进行了微观研究并分析了稳定性对液膜分离效率的影响.实验中将含重金属离子Cr(Ⅵ)的工业废水作为外水相,采用TBp-Span80-煤油体系作为油膜相,NaOH溶液作为内水相,制备了单个W1/O/W2型双重乳液颗粒系统,通过显微镜直观、实时地观察不同组成的双重乳液系统的稳定性,同时采用此乳状液膜体系对废水中的Cr(Ⅵ)进行了去除实验,将实验与机理研究相结合,通过研究pH值、表面活性剂、载体及内水相组成等对乳状液膜稳定性和Cr(Ⅵ)提取率的影响,阐明了液膜稳定性与液膜法去除Cr(Ⅵ)的分离效率之间的内在联系.实验结果表明,在选择条件下,经过一次性处理10 min后,Cr(Ⅵ)的提取率可达99.3%以上,残余质量浓度降至0.5 mg/L,达到国家排放标准.     

液膜法提取分离对氨基苯甲酸的研究

由磷酸三丁酯(TBP)、表面活性剂和煤油为油相,氢氧化钠溶液为内水相,含对氨基苯甲酸(PABA)的水溶液为料液(外水相),组成了W/O/W型乳状液膜体系,用乳状液膜法对料液中的PABA进行了分离富集研究。探讨了PA-BA在水中的形态分布及其液膜分离的传质机理,考察了表面活性剂种类、TBP质量分数浓度、外水相pH值和内水相氢氧化钠浓度等因素,对PABA传质分离的影响。结果表明,采用适宜的乳状液膜体系,在最佳的操作条件下,对含PABA浓度为500 mol/L的料液进行分离富集时,仅经一级液膜分离过程,PABA的分离提取率可达99%。     

乳状液膜法处理苯胺废水的实验研究

采用乳状液膜法处理苯胺质量浓度为1 000 mg/L的模拟废水,通过高速分散器制乳、搅拌器提取等操作,得到稳定的W/O/W的乳状液膜体系.考察了膜增强剂质量分数、表面活性剂质量分数、内水相盐酸浓度、外水相pH、乳水比等因素对苯胺传质速率和提取率的影响,并得到各因素的适宜操作范围.     

纳米TiO_2溶胶W/O型乳液的稳定性及其微胶囊化研究

在W/O/W复相乳液体系中,TiO2溶胶W/O型乳状液的稳定性对所制备的微胶囊形貌影响很大。以破乳率为衡量标准,借助显微镜观察,探讨了内水相含量、Span-80用量、乳化速率和乳化时间等参数对W/O型乳状液稳定性的影响。结果表明,当TiO2溶胶含量为50%(v)、Span-80体积分数为5%时,乳状液的稳定性较好,存在较优的乳化速率8000~10000 r·min-1,和乳化时间8~10 min。以聚乙烯醇(PVA)水溶液为外水相、戊二醛(GA)为交联剂,在稳定的W/O型乳状液基础上所制备的微胶囊粒径均匀,分散性好。热分析表明,微胶囊中TiO2的含量约为35%。     

光催化法处理含Cr(VI)废水的研究

采用P 25 TiO2作为光催化剂,研究了废水的pH值、Cr(VI)的初始浓度、气氛及有机物等因素对含铬废水中Cr(VI)去解率的影响。结果表明,在pH值为3.0时,光催化反应速率最大;反应气氛对该体系中Cr(VI)的光催化还原无明显影响;苯酚、葡萄糖等有机物的存在能有效地促进Cr(VI)的光催化还原,当加入与Cr(VI)等物质的量的苯酚或葡萄糖时,150 mL反应液[Cr(VI)浓度为0.96 mmol/L],0.15 g光催化剂,经12 W紫外灯照射反应120 m in,Cr(VI)完全被去除,相对于在反应体系中不加有机物时,Cr(VI)光催化还原效率提高了近100%;Cr(VI)的光催化还原符合L-H动力学规律。     

大块液膜技术处理含六价铬废水

以磷酸三丁酯(TBP)为载体,煤油为稀释剂,NaOH为反萃剂,采用大块液膜技术处理含95~100mg/LCr(VI)的模拟废水。考察了液膜相用量、载体体积分数及反萃剂浓度对大块液膜过程中Cr(VI)传质过程的影响。结果表明,大块液膜技术对废水中Cr(VI)的去除效果较好。Cr(VI)迁移速率随TBP体积分数的提高而加快。当反萃剂NaOH浓度大于0.5mol/L时,反萃剂浓度对Cr(VI)传质过程的影响较小。处理后废水中Cr(VI)含量降至0.5mg/L以下,达到国家排放标准。     

乳化液膜法处理含铬废水的研究

采用span-80-煤油－NaOH液膜体系对含Cr(VI)废水的处理进行了研究，讨论了不同操作条件对Cr(VI)去除率的影响，得出了提取Cr(VI)的最佳实验条件，实验结果表明：含Cr(VI)废水经液膜处理后，Cr(VI)的去除率可达98％。     

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％。     

乳状液膜法从磷矿浸出液中提取稀土的研究

针对贵州织金磷矿伴生微量稀土元素的特点,采用乳状液膜工艺对磷矿盐酸浸出液进行了稀土提取试验研究。考察了流动载体种类及质量分数、表面活性剂种类及质量分数、内水相盐酸酸度、外水相酸度、油内比、乳水比等因素对稀土提取效果的影响。结果表明:在以Cyanex272为流动载体,质量分数为6%,N205为表面活性剂,质量分数为9%,内水相盐酸酸度为7mol/L,外水相pH为1.4,油内比为1∶1,乳水比为1∶30的条件下,采用Cyanex272-N205-HCl-磺化煤油组成的液膜体系提取稀土,可使稀土提取率达91.60%。     

流变调节剂对W/O型乳液稳定性和流变性的影响

采用均质乳化法制备了W/O型乳液,研究了高分子水溶性聚合物（黄原胶、透明质酸钠）和油相增稠剂（山嵛酸甘油酯、二甲基二硬脂基铵锂蒙脱石）对W/O型乳液稳定性和流变性的影响。实验结果表明,添加黄原胶后,W/O型乳液在不同稳定性测试条件下的稳定性均下降;添加透明质酸钠后,乳液的常温储存稳定性下降,但一定程度上提升了乳液的高温储存稳定性;山嵛酸甘油酯加入W/O型乳液体系后,常温和高温储存的稳定性均增加;二甲基二硬脂基铵锂蒙脱石添加后,乳液在不同条件下稳定性均增强。高分子水溶性聚合物加入后,内水相黏度上升,但W/O型乳液的表观黏度显著降低且线性黏弹区范围缩小,这可能是由于内水相黏度升高阻碍乳化剂分子在油/水界面的吸附;油相增稠剂的添加均增加了W/O型乳液的表观黏度和线性黏弹区范围,这可能和乳化粒子粒径降低和油/水界面能的变化有关。此外,流变调节剂加入后,乳液的滞后环面积均有不同程度的降低。     

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.     

Easy removing of phenol from wastewater using vegetable oil-based organic solvent in emulsion liquid membrane process

Phenol is considered as pollutant due to its toxicity and carcinogenic effect.Thus,variety of innovative methods for separation and recovery of phenolic compounds is developed in order to remove the unwanted phenol from wastewater and obtain valuable phenolic compound.One of potential method is extraction using green based liquid organic solvent.Therefore,the feasibility of using palm oil was investigated.In this research,palm oil based organic phase was used as diluents to treat a simulated wastewater containing 300×10~(-6) of phenol solution using emulsion liquid membrane process(ELM).The stability of water-in-oil(W/O) emulsion on diluent composition and the parameters affecting the phenol removal efficiency and stability of the emulsion;such as emulsification speed,emulsification time,agitation speed,surfactant concentration,pH of external phase,contact time,stripping agent concentration and treat ratio were carried out.The results of ELM study showed that at ratio7 to 3 of palm oil to kerosene,5 min and 1300 r·min~(-1) of emulsification process the stabile primary emulsion were formed.Also,no carrier is needed to facilitate the phenol extraction.In experimental conditions of500 r·min~(-1) of agitation speed,3%Span 80,pH 8 of external phase,5 min of contact time,0.1 mol·L~(-1) NaOH as stripping agent and 1:10 of treat ratio,the ELM process was very promising for removing the phenol from the wastewater.The extraction performance at about 83%of phenol was removed for simulated wastewater and an enrichment of phenol in recovery phase as phenolate compound was around 11 times.     

乳化液膜法提取废水中的阿司匹林

针对阿司匹林（ASA）结晶母液经处理后产生的废液,采用搅拌和超声结合的方法制备了乳化液膜体系来回收ASA。以环己烷为膜溶剂,Span80做表面活性剂,石蜡做膜稳定剂,氢氧化钠（NaOH）为内水相,研究了表面活性剂浓度、内水相NaOH浓度、内水相类型、外相pH、油内比、乳水比、搅拌速度、膜溶剂类型、盐浓度、ASA初始浓度等试验条件对ASA萃取效果的影响,并进行了破乳研究。结果表明：在最佳实验条件下[环己烷90%（质量分数）、Span80 6%（质量分数）、C（NaOH）=0.1mol/L、油内比1：1、水乳比1：4、搅拌速度200r/min、ASA初始浓度500mg/L],不对外相进行pH调节时,15min后ASA的萃取率可高达97.4%。对实验后的乳液进行离心破乳,20min后破乳率可达72.9%,破乳后的油相重复利用5次后,对ASA的提取率仍在76%左右。     

乳状液膜法提取红土矿浸出液中镍

采用Span-80-TBP-NH3×H2O体系乳状液膜法提取红土矿浸出液中的Ni(II),研究了膜相组成、内水相试剂浓度、膜相与内水相体积比(油内比)、乳水体积比对镍离子提取效果的影响. 采用微分法测定并比较了反应的浓度级数nC和时间级数nt. 结果表明,膜相组成为Span-80:TBP:石蜡:煤油(体积比)=5:4:2:89、内水相氨水浓度为2 mol/L、油内比为1:1、乳水体积比为1:3、外水相硫酸浓度为0.3 mol/L的条件下,经过二级提取后,红土矿浸出液中Ni(II)去除率可达80%;由浓度级数(nC=1)小于时间级数(nt=2.8)可知,该过程为化学反应控制过程.     

Removal of hydrogen sulphide from high salinity wastewater by emulsion liquid membrane

This article presents a experimental study on the removal of hydrogen sulphide (H₂S) from high salinity wastewater by emulsion liquid membrane (ELM). The ELM contains diethanolamine (DEA) as carrier, kerosene as solvent and span 80 as surfactant. The fundamental parameters (viz. surfactant concentration, carrier concentration, strip phase concentration, phase ratio, agitation speed and time) affecting the removal of H₂S were investigated to select the optimum combination of process parameters. The results showed the optimal governing parameters were: inner phase NaOH aqueous solution 2.0 wt%, Surfactant (span 80) 5.0 vol%, carrier (DEA) 6.0 vol%, treat ratio 1:5, agitation speed 250 rpm, agitation time 15 min, respectively, and removal efficiency of 97.3% was achieved. © 2011 Canadian Society for Chemical Engineering     

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.     

Efficient transport and selective extraction of Cr(VI) from waste pickling solution of the stainless steel-cold rolled plate process using Aliquat 336 via HFSLM

The selective extraction of Cr(VI) from waste pickling solution of the stainless steel-cold rolled plate process by hydrophobic hollow fiber supported liquid membrane (HFSLM) was investigated. The effects of various parameters— types of organic extractants, i.e., metyl trioctylammonium chloride (Aliquat 336), tri-n-octylamine (TOA), tri-n-butyl phosphate (TBP) and the mixture of Aliquat 336 and TBP, concentration of the selected extractant, types of stripping solutions (NaCl and NaOH), pH and concentration of the selected stripping solution, and the operating temperature—were studied. The feed and stripping solutions flowed countercurrently. The results showed that the coexisting contamination in spent pickling solution of Fe(II) and Ni(II) ions had no significant effect on Cr(VI) extraction. Among the extractants used in this study, Aliquat 336 was a specific carrier to attain the highest percentage of Cr(VI) extraction. About 70% extraction was achieved by using 0.11 M Aliquat 336 and 0.5 M NaCl at pH 7. The percentage of stripping slightly increased when the concentration of NaCl increased. In addition, it was found that the operating temperature of 20, 30, 40, and 50 °C had almost no influence on the percentages of extraction and stripping of Cr(VI). The calculated diffusion energy of Cr(VI) extraction was 15.14 kJ/mol.     

Study and Optimization of Amino Acid Extraction by Emulsion Liquid Membrane

Abstract

A batch extraction of an essential amino acid, phenylalanine, from an aqueous solution of different concentrations by an Emulsion Liquid Membrane (ELM) was developed using D2EHPA as a cationic carrier, Span 80 as the surfactant, paraffin, and kerosene as the diluents, and HCl as the internal electrolyte. All effective parameters such as the initial pH of the aqueous external phase, the electrolyte concentration in the aqueous internal phase, carrier, and surfactant concentration in the emulsion, the volume ratio of the organic to aqueous internal phase (Roi), the volume ratio of the W/O emulsion to the aqueous external phase (Rew) and time were examined and optimized using the Taguchi method. Applying the Taguchi method to analyze the experimental results, the effects and contribution of each of the factors on the extraction efficiency were obtained. The results obtained from the experiments illustrated that with a stable emulsion, by optimizing all the effective parameters, a considerable amount of phenylalanine can be extracted in a short time with an acceptable ratio of swelling and breakage.     

Extraction of Hexavalent Chromium from Aqueous Stream by Emulsion Liquid Membrane (ELM)

Emulsion Liquid Membrane (ELM) separation technique is an effective procedure for the removal of Chromium (VI) ions from the wastewater stream. In the present study, the effect of changes of different parameters such as the pH of feed solution, the stirring speed, and the emulsification time, carrier concentration, surfactant concentration, the effect on the presence of other metal ions, are systematically investigated. The membrane phase consists of kerosene with hexane as diluant, Aliquat 336 as extractant, sorbitan mono-oleate (span 80) as surfactant. 1 (N) Sodium hydroxide is the stripping solution. Results show that by the ELM process, 90% Cr(VI) can remove successfully in optimum condition from feed.