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三相结构离子交换膜是一类具有惰性相、离子交换基团相和辅助功能基团相的特殊结构材料。传统两相结构离子交换膜受限于离子通量和选择性的相互制约,难以实现两者同步提升。因此,研究者开始关注新型三相结构,以改善离子传质路径。综述了离子交换膜从两相结构到三相结构的发展,介绍了微相分离离子交换膜、自具微孔离子交换膜、有机硅烷杂化离子交换膜和基于氧化石墨烯或金属有机框架的“三相”结构离子交换膜,讨论了离子膜介尺度中的相结构、孔道结构和缺陷等问题,并概述了三相结构在燃料电池、液流电池、一/二价离子分离和酸碱回收等领域所发挥的作用,以期给三相结构指导离子交换膜制备并提升性能提供策略参考。 相似文献
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渗透汽化脱水技术及其在酯化工业中的应用 总被引:6,自引:0,他引:6
渗透汽化是分离某一液体物质含量较低的液体混合物的实用分离方法.高性能渗透汽化膜的开发、膜组件及系统的合理设计是实现膜技术工业化的两个关键因素.分析了渗透汽化膜用于酯化工业耦合脱水工艺的研究现状,展望渗透汽化膜在制备乳酸酯的酯化反应、双酚A的缩合反应和手性化合物的酯合成反应等方面的应用前景. 相似文献
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膜分离技术作为一种新型化工分离单元,发展速度极快,无论在膜透过理论方面还是开发新膜材料及制膜工艺方面都取得了很大进展。文章对高分子分离膜的发展及分类、制备方法、分离机理和过程进行了综述,同时阐述了膜分离技术在工业中的应用及新型膜的开发与应用。相信高分子分离膜定能作为高效能材料而成为开发的萤点,并进一步获得发展。 相似文献
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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。 相似文献
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Zhixue Li Zhun Ma Yuting Xu Xiaomeng Wang Yongchao Sun Rong Wang Jian Wang Xueli Gao Jun Gao 《Korean Journal of Chemical Engineering》2018,35(8):1716-1725
Ion exchange membranes (IEMs) composed of sulfonated poly (ether sulfone) (SPES) and N-phthaloyl chitosan (NPHCs) were synthesized. NPHCs was employed in membrane fabrication to improve the porosity and hydrophilicity of membranes. The effect of blend ratio of sulfonation (DS) and NPHCs content on physico-chemical characteristics of home-made membranes was investigated. The morphology of prepared membranes was investigated by Fourier transform infrared spectroscopy (FTIR), X-ray diffractometer (XRD) and scanning electron microscopy (SEM). SEM images revealed the formation of a more porous membrane structure and smoother surface. The electrochemical and physical properties of CEMs were characterized comprising water content, contact angle, ion exchange capacity (IEC) and thermal stability. Membrane water content, surface hydrophilicity and IEC were enhanced with increase of DS and NPHCs blend ratios in casting solution. Furthermore, the diffusion coefficient was also improved slightly with increase of DS and NPHCs blend ratios in prepared membranes. Membrane potential, permselectivity, transport number and areal membrane resistance all showed decreasing trends by the increase in NPHCs blend ratio in casting solution. These results indicated that the prepared membrane has good prospective and great potential for desalination in electrodialysis applications. 相似文献
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离子交换膜具有分离效果好、能耗少和环保等特点,已经逐渐被应用于化工、海水脱盐、废水治理等领域。根据离子交换膜的分离机理不同,可将其在水处理中的应用分为电渗析、扩散渗析和Donnan渗析等三种,对三种分离方法的机理作了详细介绍,并举例说明了离子交换膜在水处理中的巨大潜力。 相似文献
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高盐废水“零排放”是当今很多企业需要面临的非常严峻的环保问题,而离子膜电渗析由于其独特的分离机制能够实现高盐废水中无机盐的分离、浓缩和资源化利用,从而实现水和盐的回收利用。本文综述了离子膜电渗析目前在高盐废水“零排放”盐浓缩工艺中的应用情况;展望了电渗析在高盐高COD废水中的应用前景以及新型的电渗析技术如选择性电渗析和双极膜电渗析在混盐分离和盐的资源化利用中的机遇;同时指出离子膜电渗析在大规模应用中仍存在很多挑战,如离子膜性能的提高、电渗析工艺的优化和电渗析设备的投资成本和能耗如何降低。本文将为高盐废水“零排放”提供新思路,同时为离子膜电渗析在高盐废水“零排放”中的规模化应用奠定基础。 相似文献
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Synthetic membranes are used for a great variety of separation processes such as dialysis, electrodialysis, hemodialysis and hemofiltration, ultra-and hyperfiltration, and pervaporation, listing the most usual ones, where the process is generally designated according to the applied driving force such as a concentration, electrical potential, or pressure difference, respectively, across the membrane. Rather common requirements on the membranes used for separation processes are high flux, excellent permselectivity, chemical and partially temperature resistivity as well as high durability (long life time), to name the most important ones out of additional distinct qualifications which a membrane has to meet regarding an individual application. Therefore, a great deal of work was spent during the last 25 years for the development of the best possible membranes using almost every available polymeric material. At the beginning of membrane research, natural polymers such as cellulose and cellulose derivatives were essentially employed for the preparation of appropriate membranes such as collodion and cellulose acetate, for instance. These polymeric materials became rediscovered for the preparation of desalination membranes installed into hyperfiltration modules for the production of fresh water from brackish and seawater. In this connection, new membrane structures and configurations were designed besides the common homogeneous flat sheet membrane in order to meet the demands of high flux and high packaging density of a corresponding membrane module. With respect to an improved packaging density, spiral-wound, tubular, capillary, and hollow-fine fiber modules were designed in addition to the classical plate and frame module. Moreover, asymmetric and so-called composite membranes were developed to generate high flux membranes possessing the same selectivity as the corresponding homogeneous ones. Concurrently to the development of new membrane structures and configurations, new polymeric materials such as polyamides, polyimides, polysulfone, polypropylene, polycarbonate, polyurethane, copolyacryl nitriles, silicone, polytetrafluor ethylene (PTFE), and polybenzimidazolone, for example, were cast into membranes of improved transport properties and chemical resistivity. The different membranes together with their structure and field of application as well as their advantages and disadvantages will be discussed. 相似文献
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电泳膜接触器(EMC)是在传统电渗析器中引入多孔膜,或用多孔膜代替部分离子交换膜的一种新型膜分离技术,其中多孔膜作为两液流的接触界面,提供传质的场所,垂直于液流方向的电场是唯一的驱动力。本文介绍了EMC的工作原理,并简要概述了EMC的膜堆构型及运行模式。详细分析了进料液pH值、电场强度等操作参数、多孔膜的材质和截留相对分子质量等对EMC过程传质的影响,且对EMC运行过程中多孔膜的污染状况进行了探讨,并展望了EMC在生物大分子分离和纯化中的应用潜力。EMC中多孔膜的引入,使得EMC可以用于相对分子质量大于500 Da的生物分子的分离与纯化,进一步拓宽了电渗析的应用领域,而外加电场的作用能够有效减轻多孔膜的污染,因此,EMC在生物分子的分离与纯化方面具有广阔的应用前景。 相似文献
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Kamalesh K. Sirkar 《Chemical Engineering Communications》1997,157(1):145-184
This article provides a brief overview of major developments in membrane separation technologies over the last six years until 1995. Progress in membrane separation processes, membrane separation techniques and membranes for given separation problems are of primary interest. The order of importance for membrane separation technologies is: already commercialized, being commercialized and having great potential based on laboratory performance. Separations involving liquid solutions, gaseous mixtures and particle removals have been covered. Notable recent developments in eight commercialized technologies namely, reverse osmosis, ultrafiltration, microfiltration, electrodialysis, dialysis, pervaporation, gas permeation, emulsion liquid membrane are illustrated first. New membrane-based equilibrium separation processes involving gas-liquid and liquid-liquid contacting, distillation and adsorption are then considered. The progress in new membrane-based rate-governed separation processes of vapor permeation and continuous deionization are treated next followed by a number of developing techniques, e.g., perstraction, facilitated transport, osmotic distillation, contained liquid membrane, supported liquid membrane and supported polymeric liquid membrane. Developments in hybrid separation processes where one of the techniques employs membranes are identified. The potential and current reality of membrane reactors is provided at the end. 相似文献
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相较于传统聚酰胺薄层复合(TFC)膜,金属有机骨架/聚酰胺薄层纳米复合(TFN)膜得益于MOFs材料的高比表面积、有序可控的孔隙结构、良好的聚合物相容性和可定制的化学功能,展现出更高的渗透选择性,在工业应用中显示出巨大的分子和离子分离潜力。本文首先简述了MOFs聚酰胺复合膜的研究背景,然后从MOFs材料的特性和MOFs聚酰胺复合膜的制备策略两个方面出发,总结了MOFs聚酰胺膜研究的最新进展。讨论了MOFs的物化特征在TFN膜的微观结构和分离性能中起的作用;介绍了MOFs聚酰胺复合膜的制备策略,重点对MOFs负载方法及效率进行了分析。最后简述了MOFs聚酰胺复合膜在气、液体系分离中的应用;对MOFs聚酰胺膜在应用过程中的稳定性问题进行了分析,并对未来MOFs聚酰胺复合膜优化MOFs负载和功能性设计的研究进行了展望。 相似文献
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为缓解电渗析膜污染,提高电渗析性能,采用阴膜扩散渗析对待脱盐的赖氨酸离子交换废液进行净化处理,对扩散渗析回收的(NH4)2SO4溶液进行电渗析脱盐浓缩。结果表明,当扩散渗析流量为5.6 L/h时,扩散渗析的扩散系数达2.24?10?7 cm2/s,离子交换废液中(NH4)2SO4透过率约为30%,可截留90.1% Mg2+和94.5%有机氮、80.3%蛋白、86.0%总糖、79.3%化学需氧量(COD);与直接电渗析赖氨酸离子交换废液相比,对扩散渗析回收的(NH4)2SO4溶液进行电渗析脱盐浓缩,SO42?膜通量、电流效率分别提高了55.7%和18.3%,操作时间、单位膜通量能耗分别降低了26.1%和42.3%。用扩散渗析净化赖氨酸离子交换废液可有效缓解后续电渗析的膜污染,提高电渗析性能。 相似文献