分散支撑液膜体系中Cd(Ⅱ)的传输研究

以聚偏氟乙烯膜(PVDF)为支撑体,煤油为膜溶剂,2-乙基己基膦酸-单-2-乙基己基酯(PC-88A)为流动载体,研究了分散支撑液膜体系中金属Cd(Ⅱ)的传输行为;考察了料液pH、膜溶液与解析剂体积比、解析相中HCl浓度以及Cd(Ⅱ)的起始浓度对Cd(Ⅱ)传输的影响.结果表明,以HCl为解析剂,料液pH=5.0、膜溶液与解析液体积比为160:40、解析相中HCl浓度为4.0 mol·L-1时,该分散支撑液膜体系对金属cd(Ⅱ)具有良好的传输作用.在最优条件下,料液相中Cd(Ⅱ)的初始浓度为3.00×104mol·L-1时,传输190min,传榆率可达82.65%.     

PC-88A-煤油-HCl分散支撑液膜体系中Zn(Ⅱ)的传输与分离研究

以聚偏氟乙烯膜(PVDF)为支撑体,煤油为膜溶剂,2-乙基己基膦酸-单-2-乙基己基酯(PC-88A)为流动载体,研究了分散支撑液膜体系中金属Zn(Ⅱ)的传输行为;考察了料液pH、膜溶液与解析剂体积比和解析相中HCl浓度对Zn(Ⅱ)传输的影响.结果表明,以HCl为解析剂,料液pH为4.0、膜溶液与解析液体积比为160:40、解析相中HCl浓度为4.0 mol·L-1时,该分散支撑液膜体系对金属Zn(Ⅱ)具有良好的传输作用,传输190 min,传输率可达90%,在相同的条件下传统的支撑液膜只有72.8%.在Zn(Ⅱ)的最佳传输条件下,对Zn(Ⅱ)/Cu(Ⅱ)、Zn(Ⅱ)/Co(Ⅱ)进行了分离试验,分离效果很好,该体系能够实现金属离子的传输和分离.     

PC-88A为载体的大块液膜体系Cu(II)传输动力学

采用以2-乙基己基膦酸-2-乙基己基单酯(PC-88A)为载体、CHCl3为膜溶剂的大块液膜分离体系,研究了搅拌速度、载体浓度、体系温度对铜离子迁移的影响. 获得了不同反应温度下的表观反应速率常数,萃取与反萃取表观反应活化能分别为41.97和8.59 kJ/mol. 铜离子的迁移过程可用2个串联的准一级不可逆过程描述,萃取过程化学反应为控速步骤,反萃取过程扩散为控速步骤.     

PC-88A为载体的大块液膜体系Cu(Ⅱ)传输动力学

采用以2-乙基己基膦酸.2.乙基己基单酯(PC-88A)为载体、CHCl3为膜溶剂的大块液膜分离体系,研究了搅拌速度、载体浓度、体系温度对铜离子迁移的影响.获得了不同反应温度下的表观反应速率常数,萃取与反萃取表观反应活化能分别为41.97和8.59 kJ/mol.铜离子的迁移过程可用2个串联的准一级不可逆过程描述,萃取过程化学反应为控速步骤,反萃取过程扩散为控速步骤.     

磷酸三丁酯/煤油支撑液膜体系中苯酚的传质分离

研究了苯酚在以多孔聚丙烯平板膜(Celgard2500)为支撑体、磷酸三丁酯(TBP)为膜载体和煤油为膜溶剂的支撑液膜体系中的传质过程;用传统萃取法测定了TBP/煤油体系中苯酚络合物摩尔比为1∶1,同时得到25.0℃萃取平衡常数为96.72;考察了原料相pH值、初始质量浓度、膜二侧转速、载体浓度和反萃取相碱浓度对苯酚传质的影响,确定了该体系分离苯酚的最佳条件:原料相pH<9,苯酚初始质量浓度<1 000 mg/L,膜二侧转速>300 r/m in,载体浓度为0.55 mol/L,反萃取相碱浓度0.10 mol/L;根据双膜理论提出苯酚的传质动力学方程,采用直线斜率法计算了苯酚在TBP/煤油支撑液膜体系中的扩散层厚度和膜内扩散系数,计算结果表明动力学方程计算值能较好地与实验值吻合,平均相对误差在2%以内。     

支撑液膜稳定性研究进展

分析了导致支撑液膜不稳定的因素及其机理。主要提出了近年来各国学者在改进支撑液膜稳定性方面所作的努力,包括对支撑液膜的结构、液膜相组成和制备工艺、膜支撑体以及膜组件改进等方面的工作。最后对支撑液膜的工业化前景进行了展望。     

铝基复合材料表面四价铈转化膜的研究

研究了铝基复合材料Ａｌ６０６１／ＳｉＣｐ表面四价铈转化膜的成膜工艺,讨论了各工艺参数对转化膜性能的影响。利用湿热试验、盐水浸渍试验和电化学方法评价了转化膜的耐腐蚀性能并与其它类型转化膜进行了比较,结果表明四价铈转化膜的耐腐蚀性能优于复合材料Ａｌ６０６１／ＳｉＣｐ表面的化学氧化膜和阳极氧化膜。     

离子液体在支撑液膜中的应用

简要叙述了利用离子液体作为膜液相来制备支撑液膜的方法,分析了影响支撑离子液体膜稳定性的主要因素.对支撑离子液体膜的应用情况做了详细综述,内容包括气体分离、有机混合物的分离以及化学反应等3个方面,并对其工业化前景进行展望.     

离子液体支撑液膜应用研究进展

离子液体作为一种新型绿色介质,受到研究学者的广泛关注。离子液体具有不易燃、无味、无污染、无蒸汽压、可循环使用等独特性质,被广泛应用于化学化工过程中。离子液体用于膜分离技术具有不易挥发、稳定性好的特点,近来对离子液体在支撑液膜方面的研究备受关注,离子液体支撑液膜在污染性气体的吸收分离方面具有高选择性、高渗透性等优势,在有机物的分离方面具有分离效果明显、耐用性强等优势,在化学反应方面具有催化效率高、可循环使用等优势,本文介绍了离子液体支撑液膜的常用制备方法和膜基材料的选择,探讨了离子液体支撑液膜的稳定性和分离选择性的影响因素,对离子液体支撑液膜在气体分离、有机物的分离、化学反应等方面的应用研究进行了综述。     

几种新型的支撑液膜组件的结构型式

本文介绍四种新型支撑液膜组件的型式和特点。它们分别是：中空纤维夹芯型膜组件、管式－中空纤维混合式膜组件，板式夹芯型膜组件和框式隔板夹芯型膜组件。     

P507溶于煤油作为载体的一种新型分散组合液膜对Eu3+的分离

The separation of Eu3+ is studied with a dispersion combined liquid membrane (DCLM), in which polyvinylidene fluoride membrane (PVDF) is used as the liquid membrane support, dispersion solution containing HCl solution as the stripping solution, and 2-ethyl hexyl phosphonic acid-mono-2-ethyl hexyl ester (P507) dissolved in kerosene as the membrane solution. The effects of pH value, initial concentration of Eu3+ and different ionic strength in the feed phase, volume ratio of membrane solution to stripping solution, concentration of HCl solution, concentration of carrier, different stripping agents in the dispersion phase on the separation are investigated. The optimum condition for separation of Eu3+ is that concentration of HCl solution is 4.0 mol&#8226;L&#61485;1, concentration of carrier is 0.16 mol&#8226;L&#61485;1, and volume ratio of membrane solution to stripping solution is 30︰30 in the dispersion phase, and pH value is 4.2 in the feed phase. The ionic strength has no significant effect on separation of Eu3+. Under the optimum condition, when the initial concentration of Eu3+ is 0.8×10&#61485;4 mol&#8226;L&#61485;1, the separation percentage of Eu3+ is 95.3% during the separation time of 130 min. The kinetic equation is developed in terms of the law of mass diffusion and the theory of interface chemistry. The diffusion coefficient of Eu3+ in the membrane and the thickness of diffusion layer between feed phase and membrane phase are obtained and their values are 1.48×10&#61485;7 m2&#8226;s&#61485;1 and 36.6 μm, respectively. The results obtained are in good agreement with literature data.     

La(III) Transport in Dispersion Supported Liquid Membrane Including PC-88A as the Carrier and HCl Solution as the Stripping Solution

The transport of La(III) through a dispersion supported liquid membrane with polyvinylidene fluoride membrane as the liquid membrane support and dispersion solution including HCl solution as the stripping solution and 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (PC-88A) in kerosene as the membrane solution, was studied. As a result, the optimum transport conditions of La(III) were obtained as that concentration of HCl solution was 4.0 mol/L, concentration of PC-88A 0.16 mol/L, and volume ratio of membrane to stripping solution 30:30 in the dispersion phase, and pH value 4.0 in the feed phase. Ionic strength had no obvious effect on the transport of La(III). Under the optimum conditions, when initial concentration of La(III) was 0.8′10-4 mol/L, the transport rate was up to 96.3% during the transport time of 125 min. The kinetic equation was developed based on the law of mass diffusion and theory of interface chemistry. The diffusion coefficient of La(III) in the membrane and the thickness of diffusion layer between feed and membrane phases were obtained as 3.20′10-7 m2/s and 3.22′10-5 m, respectively. The calculated results were in good agreement with experimental results.     

离子液体支撑液膜技术及其在气体分离中的研究进展

分析离子液体支撑液膜的气体分离机理,总结目前离子液体支撑液膜的制备方法以及不同膜材料、不同离子液体及其亲疏水性对离子液体支撑液膜稳定性的影响。介绍离子液体支撑液膜在气体分离中的应用,对离子液体支撑液膜的工业化前景进行了展望。     

离子液体-中空纤维支撑液膜技术分离Cs／Mo研究

支撑液膜（SLM）发展迅速、应用前景广阔,在众多支撑液膜性能改进的研究中,采用离子液体（IL）代替传统有机溶剂,已在气体、有机物分离以及生物反应器方面有一定的进展。本实验采用疏水性聚丙烯中空纤维（HF）作支撑体,针对目标金属Cs离子选择杯冠化合物DB18C6作萃取剂,预选[Bmim][PR]、[Bmim][NTf2]和[Bmim][BF4]三种ILs作稀释剂制备膜体系,探索其在Cs／Mo分离中的应用潜力。结果表明,在本实验工艺条件下,使用[Bmim][PF6]成功制备了离子液体中空纤维支撑液膜体系（IL—HFSLM）,该液膜体系在料液流速低于5mL／min的条件下稳定存在,并可实现从含Mo溶液中回收超过80％的Cs。     

Simultaneous Transport and Separation of Cu(II) and Zn(II) in Cu-Zn-Co Sulfate Solution by Double Strip Dispersion Hybrid Liquid Membrane (SDHLM)

A double strip dispersion hybrid liquid membrane (SDHLM) was successfully used in the simultaneous extraction and separation of Cu(II), Zn(II), and Co(II) from Cu-Zn-Co dilute feed phase. In the double SDHLM system, Acorga M5640-loaded membrane was placed between the 1st and the 2nd compartment, whereas the mono(2-ethylhexyl) 2-ethylhexyl phosphonate [HEH(EHP)]-loaded membrane was placed between the 1st and the 3rd compartment of the transport cell. The feed solution was filled in the central feed compartment(1st compartment) of the transport cell. The effect of the different experimental variables on separation was examined. The optimum separation conditions were summarized.

An analysis of mass transfer resistances in the double SDHLM system shows that the mass transfer resistance for the diffusion of Zn(II) ions in the microporous membrane phase is dominant and the mass transfer resistances for the diffusion of copper (II) ions in the aqueous boundary layer and in the microporous membrane phase are dominant in comparison with the overall mass transfer resistance. The experiments verify that the double strip dispersion hybrid liquid membrane (SDHLM) possesses the nonequlibrium mass transfer characteristic.     

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.     

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.     

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.     

液膜分离技术及在医药化工中的应用

介绍了液膜分离技术的分类、优点、局限性和改进研究,论述了该技术在氨基酸、抗生素、生物碱及蛋白质等医药化工中的应用情况,并对其前景进行了展望。