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％。     

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。     

液膜分离技术脱除废水中的醋酸——外相边界层及膜相扩散控制模型

本文导出了无再分散、无内循环、乳液滴直径均匀的液膜系统中的扩散控制模型。此模型同时考虑了外相边界层及膜相传质阻力。采用摄动法求得了非线性方程组的近似解。解中所含参数M,代表外相边界层中的传质阻力与乳液滴内最大传质阻力之比。当M等于零时,此解与渐进前沿模型的解相同。实验数据与模型计算值能很好吻合。通常,零级解(即拟稳态解)即可描述液膜传质。乳液溶胀可分为渗透溶胀与夹带溶胀。渗透溶胀速率随表面活性剂及内相试剂浓度的增加而增加。多次聚结再分散及增加搅拌强度加速了夹带溶胀。当内相试剂浓度较高时,渗透对溶胀的影响较大。本文提出了夹带溶胀机理。     

改进的Ⅱ型促进迁移液膜传质渐进前沿模型

提出了改进的Ⅱ型促进迁移液膜传质渐进前沿模型,该模型不仅考虑了滴内外扩散阻力、外界面反应,还同时引进了乳液渗透溶胀和液膜破损效应。用间歇式液膜提取苯丙氨酸进行了定量验证。模型计算值和实验值吻合良好。     

聚丙烯支撑液膜提取柠檬酸的传质条件

用聚丙烯支撑液膜从柠檬酸溶液中提取柠檬酸,通过正交实验考察和分析料液相浓度、反萃取相浓度、搅拌速率、温度等因素的影响,得到最佳传质条件：料液相浓度为0．4mol／L、反萃取相浓度0．1mol／L、搅拌强度300r／min、传质温度25℃。同时对该膜体系进行连续提取实验,结果表明最佳传质条件下膜体系稳定性较好,膜通量下降后可通过重新浸泡得以恢复,继续使用。     

溶胀对中空纤维膜萃取器中的流动和传质性能的影响

溶胀是中空纤维膜萃取工业化必须要解决的关键问题之一。本文通过拍摄电镜照片，观察了溶胀前后中空纤维膜表面形态，孔隙率，膜孔径，膜孔道弯曲状况等微观结构的变化。结果表明，溶胀会使中空纤维膜孔隙率减小，膜孔径变小，弯曲因子增大，通过测量发现，溶胀后膜长度增加，而膜的内外径，膜厚基本不变。本文还研究了溶胀时间对中空纤维膜器中的流动及传质效果的影响，通过测量聚丙烯和聚砜中空纤维膜器管程和壳程的停留时间分布曲线表明，对于装填密度较高的膜器，溶胀时间对壳程和管程中的流动状况的影响可以忽略。此外，本文以正辛醇－苯胺－水为实验体系，在中空纤维膜器中进行了循环逆流传质实验。实验证明，由于溶胀使纤维膜阻增加，膜器的传质性能随时间的增加而下降。     

有机硅改性丙烯酸酯乳液及其外墙涂料的研究

采用溶胀法制备有机硅改性丙烯酸酯复合乳液并配制外墙涂料，研究了有机硅含量、颜料体积浓度以及硅酸乙酯水解物含量对涂料性能的影响。结果表明，有机硅可大大改善丙烯酸酯乳液型外墙涂料的性能。     

乳化液膜萃取Cr(Ⅲ)的传质模型研究

采用经合理简化后的Ⅱ型渐进前沿性模型对DEHPA-Span80-液体石蜡-煤油乳化液膜体系萃取分离Cr(Ⅲ)的传质模型进行研究,此模型不仅考虑乳滴内、外扩散阻力、乳滴外界面反应,还同时考虑了乳液渗透溶胀和液膜破损效应。模型经过简化后,使用Matlab软件绘制曲线与实验结果进行对比。结果表明:模型与实际情况较为符合,在该传质过程中,传质阻力主要为乳滴内、外扩散阻力、乳滴外界面反应,且乳液渗透溶胀作用对液膜萃取影响比较大,膜破损阻力可忽略不计。     

OP-10/异戊醇/煤油/NaOH微乳液体系萃取钼(Ⅵ)的研究

采用电导率法研究了OP-10/异戊醇/煤油/NaOH水溶液微乳液体系的性质,并以此微乳液体系为油相,以TOA为载体研究了萃取水溶液中钼(Ⅵ)的工艺条件。实验结果表明:异戊醇和OP-10的最佳比例为1∶1时,该微乳液体系具有最大溶水量;拟三元相图表明该微乳液体系的稳定区域与NaOH浓度关系不大;外水相中加入一定量的NaCl可有效避免萃取过程中液膜的溶胀与破裂;当外水相中HCl浓度为0.05mol/L、膜相中TOA浓度为0.04mol/L、内水相中NaOH浓度为0.04mol/L时,微乳液体系对钼的单级萃取率可达98%。     

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.     

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.     

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.     

Separation of cadmium(II) from spent nickel/cadmium battery by emulsion liquid membrane

Experiments were conducted to investigate the separation of cadmium(II) from spent nickel/cadmium battery by emulsion liquid membrane. Liquid membrane mainly consisted of a diluent (kerosene), a surfactant (Span 80), a carrier (di(2‐ethylhexyl) phosphoric acid, D2EHPA) and an internal phase (sulfuric acid). Main research effort was focused on the identification of optimal parameters affecting the separation process, such as D2EHPA (4.4 vol%), Span 80 (6.6 vol%), pH in the external phase (3.0), treat ratio (0.4), agitation time (10 min), and sulfuric acid concentration (1500 mol / m³). With the selected emulsion liquid membrane to separate cadmium(II) from the leaching solution of spent nickel/cadmium battery, the fraction extracted of cadmium(II) ions (0.963) was much more than that of nickel(II) ions (0.026). The organic membrane phase after demulsification was re‐mulsification and recycled up to eight times.     

用乳状液型液膜提取铕的传质机理研究

本文研究了用乳状液型液膜提取稀土元素铕的工艺条件,考查了不同因素对铕的传质速率的影响.实验结果表明,以二(2-乙基己基)磷酸为载体,硝酸为解络剂的乳状液型液膜对铕的迁移效果很好.本文重点探讨了该液膜体系的传质机理,推导出本体系的传质通量式,并用实验数据进行了验证,取得了较好的一致性.     

环戊烷/水乳化液水合法捕获烟道气中CO_2(英文)

Capture of CO2 by hydrate is one of the attractive technologies for reducing greenhouse effect.The primary challenges are the large energy consumption,low hydrate formation rate and separation efficiency.This work presents a new method for capture of CO2 from simulated flue gasCO2(16.60%,by mole) /N2 binary mixture by formation of cyclopentane(CP) hydrates at initial temperature of 8.1°C with the feed pressures from 2.49 to 3.95 MPa.The effect of cyclopentane and cyclopentane/water emulsion on the hydrate formation rate and CO2 separation efficiency was studied in a 1000 ml stirred reactor.The results showed the hydrate formation rate could be increased remarkably with cyclopentane/water emulsion.CO2 could be enriched to 43.97%(by mole) and 35.29%(by mole) from simulated flue gas with cyclopentane and cyclopentane/water(O/W) emulsion,respectively,by one stage hydrate separation under low feed pressure.CO2 separation factor with cyclopentane was 6.18,higher than that with cyclopentane/water emulsion(4.01) ,in the range of the feed pressure.The results demonstrated that cyclopentane/water emulsion is a good additive for efficient hydrate capture of CO2.     

乳状液膜法提取浓海水中溴的研究

采用乳状液膜对海水中溴进行提取分离,考查了表面活性剂的用量、内水相浓度、乳水比、油内比等因素对提取性能的影响。结果表明,以民用煤油为溶剂,0.54%体积分数的L-113A为表面活性剂,内相为0.05 mol/L的Na2CO3,油内比为1:1,制乳时间为18 min,萃取接触时间为8 min,乳水比1:40,浓海水溴的提取率达到99.4%,表明乳状液膜能有效的从海水中提取溴。     

Studies on the Recovery of Uranium from Phosphoric Acid Medium by D2EHPA/n-Dodecane Supported Liquid Membrane

Abstract

Present studies deal with the application of supported liquid membrane (SLM) technique for the separation of uranium (VI) from phosphoric acid medium using Di-2 ethyl hexyl phosphoric acid (D2EHPA)/n-dodecane as a carrier and ammonium carbonate as a receiving phase. The studies involve the investigation of process controlling parameters like feed acidity of phosphoric acid, carrier concentration, stripping agents, and the effect of thickness and the pore size of the membrane. The transport of uranium decreases with increase in the concentration of phosphoric acid in feed solution whereas it increases with increase in carrier concentration in supported liquid membrane. More than 90% uranium (VI) is recovered in 360 minutes using 0.5 M D2EHPA/dodecane as carrier and 0.5 M ammonium carbonate as stripping phase from the 0.001 M H₃PO₄ feed. Lower concentration of phosphoric acid and higher carrier concentration is found to be the most suitable condition for maximum transport of uranium (VI) from its lean sources like commercial phosphoric acid and analytical wastes generated from the analysis of uranium by Volumetric (Davis-Gray) method.     

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.