聚离子液体/PVDF共混离子传导膜的制备与性能研究

以研究高电导率、高稳定性的新型离子传导膜为目标,为电池领域的应用奠定基础.通过选用同时具有双键和离子交换基团的离子液体单体,能够制备聚离子液体的新型离子传导膜材料.采用溶剂法将聚偏氟乙烯(PVDF)和离子液体(ILS)共混,在加温条件下使离子液体单体之间发生聚合反应,制得高分子互穿网络结构的离子传导膜.系统研究了制膜过...     

多孔离子传导电池隔膜研究进展

具有高离子选择性和高电导率的离子传导膜对于以新能源为主体的新型电力系统（如液流电池、燃料电池、锂电池等）至关重要。近年来，研究者们提出了构建多孔离子传导膜以应对传统隔膜普遍存在的离子选择性和电导率之间的权衡效应。本综述从无机多孔离子传导膜、有机多孔离子传导膜以及多孔离子传导复合膜三个方面简要概述了近年来多孔离子传导膜作为电池隔膜的最新研究进展，总结了多孔离子传导膜在液流电池、燃料电池、锂电池等新能源电池中的前沿性工作，并指出未来多孔离子传导电池隔膜的研究将重点关注多孔膜结构的调控、高性能多孔膜材料的开发以及多孔膜在新型电池中的应用。     

燃料电池用阴离子交换膜分子结构研究进展

阴离子交换膜（AEMs）作为燃料电池的核心部件,其发展得到了普遍关注。然而,AEMs中聚合物骨架和阳离子基团无序的直接相连的结构导致了膜在应用过程中存在离子电导率低、碱稳定性差和机械性能不足等问题,因此对连接二者的分子结构进行设计,开发综合性能优异的AEMs很有必要。本文介绍了AEMs选择性透过的基本机理,并从不同的分子结构出发,总结了近年来应用较为广泛的嵌段结构、接枝结构、交联结构、局部高密度结构以及由局部高密度结构与其他三种结构组成的复合结构AEMs的研究进展;从离子电导率、碱稳定性、机械性能以及吸水率等方面对AEMs的性能提升进行了归纳,重点关注AEMs离子电导率和吸水率的权衡问题,并从分子结构及其组合使用的角度对燃料电池用AEMs的未来发展方向进行了展望。     

国外离子交换膜的制备和应用动向

离子交换膜是一种高聚物电解质材料,因为在膜体结构上的活性基团,带有可以解离的离子,所以具有负载电流并使离子选择透过等特性。最常见的是用于电渗析海水(或咸水)脱盐方面。这种脱盐方法,不象离子交换树脂需要酸碱再生,仅仅利用电能,即可得到满意的淡水。近年来,电渗析的应用日益广泛,例如可用于药品纯化,稀有金属回收,放射性废液处理以及同位素分离等。还有一种不用电的渗透膜,亦能从冶金废液中回收硫酸、精制镍等。离子交换膜亦能用做电池隔膜。一般常用的离子交换膜,有磺酸型阳膜和季胺型阴膜。     

Nafion全氟离子交换膜与Aciplex-F离子交换膜的比较

对Ｎａｆｉｏｎ全氟离子交换膜及Ａｃｉｐｌｅｘ－Ｆ离子交换膜的性能包括操作条件、预处理,及商务保证条款进行比较,系统地介绍了该两种离子膜的相同点与不同点,为氯碱厂选择采购离子膜产品提供依据。     

氯碱工业离子膜和电槽的进展

氯碱工业离子膜法已被公认为是一种带有方向性的氯碱生产新工艺 ,其特点是节能、优质、基本无污染、生产成本及投资均较低廉。离子膜法技术的进展是离子膜从磺酸膜到羧酸膜及羧酸 -磺酸复合膜 ,电槽从单极式到复极式 ,极间距进展到小极距或“零”极距。1　离子交换膜的进展离子交换膜是氯碱工业离子膜法制碱的核心 ,目前应用于食盐水溶液电解的阳离子交换膜 ,根据其离子交换基团的不同 ,可分为全氟磺酸膜和全氟羧酸膜和全氟羧酸 -磺酸复合膜。美国杜邦 (Dupont)公司于 1 938年起开始研制氟化学品 ,首先研制成功聚四氟乙烯 ,1 960年研制成功…     

离子交换膜及其在磷酸盐生产中的应用

一、离子交换膜的性质离子交换膜大体上可以分为均相膜与非均相膜两类。非均相膜的制法沿用了最初的制造方法,即将离子交换树脂微粉与热塑性树脂粉混合热压成型制得。它的质量远不如均相膜。均相膜一般是在共聚成膜后引入(或形成)适当的离子交换基,因而交换基在膜内是均匀分布的。随着引入(或形成)的离子交换基之不同,可以将离子交换膜分为阳膜、阴膜、阴阳两性离子交换膜、复合膜等类型。阳膜上引入了磺酸基、羧酸基等阴离子基团,阴膜     

高稳定碱性离子膜分子设计研究进展

以阴离子交换膜（碱性离子膜）为基础的能量转化与储能过程十分重要,包括碱性膜燃料电池、碱性膜电解水制氢等,该类电膜过程对未来能源结构会产生深远影响。现有阴离子交换膜存在耐碱性差、性能衰减显著的问题,严重制约高效能源储存及转化技术发展。为了获得高稳定的碱性离子膜,近年来,围绕耐碱高分子材料的分子设计开展大量工作。本综述从碱性膜材料的高分子骨架和阳离子基团两个角度出发,针对膜材料耐碱性,重点阐述聚烯烃和聚芳基的主链结构,以及非金属中心、金属中心,两类阳离子的分子结构设计策略,展望高稳定碱性膜的结构设计规律及主要挑战,为设计与合成高性能碱性离子膜,满足清洁能源转化与储能膜过程提供新思路。     

离子交换膜的发展态势与应用展望

基于离子交换膜的电膜技术,由于其独特的离子传递特性,可以用于离子物系的分离、分级,在清洁生产、节能减排、能量转换等方面有着广泛的应用前景。本文综述了离子交换膜的制备、应用过程以及组件设计等方面的前沿性进展,并对亟待解决的问题和未来的发展方向作了展望。关于膜的制备,提出了从二相到三相、从致密到微孔的新型离子交换膜结构,开发了电纳滤膜并用于一价或多价离子的分离,通量和选择性均得到提高,实现了膜功能的多样化。在应用过程中,实现了扩散渗析和电渗析过程的集成,分离效果优越,生产成本降低。同时对膜组件进行优化,设计开发出新型的卷式组件,克服了传统板式组件的诸多缺陷。值得一提的是,离子分离膜的应用领域也由初级水处理扩展到复杂物料的分离与纯化。以上研究成果将为离子交换膜的发展提供指导,加快其工业化进程。     

亲水性季铵聚砜阴离子交换膜在全钒液流电池中的应用

针对全钒氧化还原液流电池用的阴离子交换膜电导率低的问题,对其高分子链结构进行源头设计,通过N,N-二甲基乙醇胺与氯甲基化聚砜反应在接枝功能季铵基团的同时,引入亲水的羟基基团,制备了具有亲水结构的季铵化聚砜AEM。亲水结构提高了SO_4~(2-)与HSO_4~-的传输效率,提升了膜的离子电导率;季铵阳离子基团与钒离子的Donnan排斥效应,有效抑制钒离子的渗透,从而提高了膜对钒离子的选择性,进而实现了VRFB电压效率与能量效率的大幅提升。     

Water/ionic liquid/organic three-phase interfacial synthesis of coral-like polypyrrole toward enhanced electrochemical capacitance

Two interfacial synthesis strategies are proposed to synthesize polypyrrole samples for electrochemical capacitors (ECs). In contrast to water/organic two-phase route, unique water/ionic liquid (IL)/organic three-phase interface strategy is first performed to prepare coral-like polypyrrole with even better electrochemical capacitance, where 1-Ethyl-3-methylimidazolium tetrafluoroborate IL, as a “buffering zone”, is set between the water and organic phases to control the morphology and micro-structure of the polypyrrole phase during polymerization. The polypyrrole synthesized by three-phase interfacial route owns more ordered structure, less charge transfer resistance and better electronic conductivity, compared with two-phase method, and delivers larger specific capacitance, higher rate performance and better electrochemical stability at large current densities in 3 M KCl aqueous electrolyte.     

Heterogeneous Cation Exchange Membrane: Preparation,Characterization and Comparison of Transport Properties of Mono and Bivalent Cations

Polycarbonate heterogeneous cation exchange membranes were prepared by solution casting techniques using tetrahydrofuran as solvent and cation exchange resin powder as functional groups agent. The effect of resin ratio loading on properties of prepared membranes was studied. Also, transport properties of the prepared membranes for mono and bivalent cations were evaluated. Scanning electron microscopy and scanning optical microscopy were used for the membranes structure investigation. Images showed that increase of resin ratio in casting solution results in a highly uniform phase to form. Formation and propagation of voids, cavities, and cracks were facilitated through higher resin ratio loading. The water content, surface hydrophilicity, specific surface area, ion exchange capacity, ion concentration, ionic permeability, conductivity, flux, and current efficiency of the membranes were enhanced and their energy consumption, oxidative stability, and mechanical strength were declined by increase of resin ratio loading. Moreover, membranes showed higher ionic flux, current efficiency, and lower energy consumption for sodium ions in comparison with bariums. Furthermore, with the increase of resin loading, permselectivity, membrane potential and transport number of membranes were improved for monovalent ions and diminished for bivalent ones. Also, membranes exhibited lower membrane potential, selectivity, and transport number for bivalent ions in comparison with the monovalent type.     

Two-dimensional graphitic carbon nitride for membrane separation

Recent years, membrane separation technology has attracted significant research attention because of the efficient and environmentally friendly operation. The selection of suitable materials to improve the membrane selectivity, permeability and other properties has become a topic of vital research relevance. Two-dimensional (2D) materials, a novel family of multifunctional materials, are widely used in membrane separation due to their unique structure and properties. In this respect, as a novel 2D material, graphitic carbon nitride (g-C₃N₄) have found specific attention in membrane separation. This study reviews the application of carbon nitride in gas separation membranes, pervaporation membranes, nanofiltration membranes, reverse osmosis membranes, ion exchange membranes and catalytic membranes, along with describing the separation mechanisms.     

Preparation and Electrochemical Characterization of Monovalent Ion Selective Poly (Vinyl Chloride)-Blend-Poly (Styrene-Co-Butadiene) Heterogeneous Cation Exchange Membrane Coated with Poly (Methyl Methacrylate)

In this research, polyvinylchloride/ styrene-butadiene-rubber blend heterogeneous cation exchange membranes were prepared by solution casting technique using tetrahydrofuran as solvent and cation exchange resin powder as functional groups agent. Poly methyl methacrylate (PMMA) was also employed as membrane surface modifier by emulsion polymerization technique to improve the membrane selectivity and anti-fouling property. The effect of used emulsion composition on properties of home-made membranes was studied. SOM images showed uniform particles distribution and relatively uniform surfaces for the membranes. Results revealed that surface modification of membrane led to decrease in water content, ion exchange capacity, and ionic permeability in composite membranes. Membrane potential, transport number, selectivity, ionic concentration, and membrane surface electrical resistance all were increased by the PMMA coating on membrane surface. Also, the results showed that decrease of (Methyl methacrylate (MMA): Sodium dodecyl benzene solfanate (SDBS)) ratio in used emulsion during the modification process led to decrease in water content, IEC and permeability in composite membranes. Conversely, opposite trends were found for membrane potential, transport number, selectivity, and electrical resistance by (MMA: SDBS) ratio decreasing in used emulsion. Composite membranes exhibited higher potential, selectivity, transport number, and permeability for monovalent ions compared to bivalent ones. Modified membranes showed good ability in (monovalent/ bivalent) ions separation.     

焦化生化出水电渗析脱盐研究

采用电渗析技术对焦化生化出水如曝气生物滤池出水及反渗透浓水进行脱盐,考察不同废水中的离子迁移、废水脱盐及离子交换膜污染情况。结果表明:2种焦化废水采用电渗析处理具有较好的脱盐效果,其中不同离子的迁移脱除与其浓度、离子半径等密切相关。膜电阻测试表明,不同焦化废水电渗析体系中不同离子交换膜的污染存在差别。扫描电镜和红外分析表明,曝气生物滤池出水主要由有机物造成阴离子交换膜污染,而反渗透浓水主要在电渗析浓室侧的膜表面形成颗粒状的无机污染,且阳膜浓室侧比阴膜浓室侧更显著。     

Novel hollow‐fiber anion‐exchange hybrid membranes: Preparation and characterization

To develop ion‐exchange membranes for application in severe conditions, such as those with high temperatures, strongly oxidizing environments, or organic solvents, new hollow‐fiber anion‐exchange hybrid membranes were prepared by the immersion of brominated poly(2,6‐dimethyl‐1,4‐phenylene oxide) base hollow fibers in a tetraethoxysilane–ethanol solution followed by sol–gel and quaternary amination. Compared to conventional polymeric charged membranes, the prepared hybrid membranes were higher in both thermal and dimensional stabilities. The results suggest that tetraethoxysilane concentration was an important factor affecting the membrane's intrinsic properties. When the tetraethoxysilane concentration was in the range 15–45%, the final hollow‐fiber anion‐exchange hybrid membranes had an ion‐exchange capacity of 1.9–2.0 mmol/g, a water uptake of.83–1.23 g of water/g of dry weight, and a dimensional change ratio of 13–18%. An evaluation on the membranes' separation performances is underway. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

The role of ion-membrane interactions in fast and selective mono/multivalent ion separation with hierarchical nanochannels

Precise control over the nanofluid behavior of polyelectrolyte-based membranes is a primary step toward understanding the structure-morphology-property relationships to ultimately determine the mass transfer characteristics. In this study, a high-performance multistacked polyelectrolyte-based cation exchange membrane (CEM) with a heterogeneous structure and versatile surface chemistry was developed to achieve selective ion conductance. The self-assembled CEM can facilitate ion permeation with fluxes of 2.9 mol m⁻² h⁻¹ for K⁺ and 0.22 mol m⁻² h⁻¹ for Mg²⁺, reaching a mono/multivalent ionic selectivity of up to 13, outperforming mono/divalent fractionation when compared with state-of-the-art membranes. Molecular dynamic (MD) simulations illustrated the ionic transport trajectory in hierarchical channels with angstrom-scale cavities using multilayered CEMs. Both the experimental measurements and theoretical simulations indicated that ionic fractionation was associated with a large disparity in the energy barrier between mono/multivalent cations, which was the primary origin of the differences in the ion dehydration-rehydration processes in the angstrom-confinement membrane ion channels.     

离子交换膜改性的研究现状及发展趋势

离子交换膜已广泛应用于化工、废水治理等工业领域。但是,目前所使用的离子交换膜选择透过性低、机械强度差、抗污染能力弱,对离子交换膜进行改性可以改善这些性能。综述了离子交换膜的改性方法,包括组成改性（表面改性和掺杂改性）和结构改性（中空纤维结构改性和增加膜基质孔隙率改性）。通过对这些方法进行分析对比得出：表面改性和掺杂改性,以聚合物为添加剂,技术简单、易操作,并且能够提高膜的综合性能,是膜改性的重要发展方向;中空纤维结构改性,由于膜的使用条件严格、清洗困难,目前得不到广泛应用,但是中空纤维结构改性使膜的结构从根本上发生了改变,这是膜改性的一个重要途径;增加膜的孔隙率只适合多孔膜的改性,这种方法研究较少。     

Pervaporation separation of water/ethanol mixture using asymmetric ion‐exchange membranes containing aluminum ions

The asymmetric aluminum ion exchange polysulfone membranes have successfully been prepared for the dehydration of ethanol‐water mixture. The relationship between the membrane morphology, separation performance, and the ion content of membranes were discussed in this study. The experimental results showed that the separation performance of those membranes was increased upon increasing the degree of aluminum ion exchange in polysulfone membranes. Both permeation rate and separation factors of those membranes increased with increasing the degree of ion exchange. The increase in separation performance of aluminum ion exchange membranes was mainly attributed to ion crosslinking in polymer network and the hydration effects of exchanged ion in membranes. On the other hand, the operating temperature in the PV process showed a significant influence on the dehydration of water molecules in the permeate. An increase in temperature increased the permeation flux of permeate but slightly decreased its selectivity. The aluminum asymmetric ions in membranes showed a strong influence on permselectivity of asymmetric ion exchange membranes. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007