渗透蒸发膜材料开发研究

本文概述了近十几年来渗透蒸发膜材料开发研究的状况,包括用于醇水分离的透水性膜材料(包括天然高分子膜材料、共聚物及共混物和离子交换树脂三大系列)、适醇性膜材料和用于其它有机混合物分离的膜材料,并对亲水性、疏水性膜材料与醇水分离性能的关系作了描述。阐述了填料在渗透蒸发膜分离过程中的作用,简要讨论了等离子体技术和辐照技术在渗透蒸发膜材料改性方面的应用。     

壳聚糖渗透蒸发膜的研究进展

综述了利用各种技术对壳聚糖膜进行改性以获得各种类型的渗透蒸发膜的方法，并对改性后膜的渗透蒸发分离性能作了阐述．     

填充型渗透蒸发膜的材料选择和制备

填充型渗透蒸发膜将填充剂的高吸附容量和膜过程的连续性的优势有效集成．以创造出适宜的膜结构形态并赋予膜以新颖和期望的理化特性，从而提高膜的渗透通量、选择性和力学强度等，因而在有机物脱水、水中有机物脱除和有机物-有机物分离等领域具有良好的应用前景。文中从膜的分类，膜材料的选择以及膜的制备方法三个方面对填充型渗透蒸发膜进行简要评述。     

乳胶渗透蒸发膜分离醇水混合物

以苯乙烯、丙烯酸丁酯为单体进行乳液聚合,将聚合获得的乳胶直接浇铸制备出乳胶膜．将该膜用于水－乙醇混合物的渗透蒸发分离,优先透水,渗透通量为50一450g／（m2·h）,分离因子为80～260．考察了乳胶膜的选择性及料液浓度对乳胶膜分离性能的影响．研究了塑化效应和耦合效应对组分渗透的影响,发现在乳胶膜中,乙醇的存在有利于水的渗透,而水的存在会阻止乙醇的渗透．     

甲壳素和壳聚糖膜材料的研究进展

本文综述了甲壳素和壳聚糖及它们的衍生物制备反渗透膜、超滤膜、渗透汽化和蒸发渗透膜的最新进展，可能是一类很有发展前途的天然高分子膜材料。     

交联壳聚糖共混膜醇水混合液分离性能研究

研究了醇水混合液体系在经交联的聚乙二醇／壳聚糖共混膜中的渗透蒸发分离性能．讨论了共混膜组成、料液浓度和温度、膜下侧压力等对渗透蒸发性能的影响．结果发现聚乙二醇的掺入能大大提高壳聚糖膜的渗透通量，但分离因子降低．当料液乙醇质量分数为８０％时，渗透通量及分离因子都随温度的升高而增加．料液中加入少量ＺｒＯＣｌ２能把分离因子从原来的８．８提高到７４．同时发现膜下游侧压力不仅仅影响渗透组分在膜表面的蒸发，还影响整个渗透蒸发传质过程．     

渗透蒸发与化学反应耦合过程的研究（I）

分析了渗透蒸发和渗透蒸发与化学反应耦合的传质过程，建立了渗透蒸发膜促进化学反应的数学模型，它能较准确地描述渗稼蒸发膜分离过程对化学反应的影响，并讨论了模型参数的物理意义及其变化趋势。     

优先透有机物渗透汽化膜的研究进展

渗透汽化膜分离技术是当前分离膜研究中最活跃的领域之一,作为分离技术中的重要组成部分,近年来受到高度重视.随着现代工业的发展,与优先透水膜相比,优先透有机物膜具有更大的发展潜力和应用价值,本文简述了优先透有机物渗透汽化膜材料的研究进展和改性状况。     

PVDF超疏水微孔膜调控研究

提高疏水膜表面的疏水性是降低其应用过程中润湿风险的有效方法.为了便捷有效地调控膜结构从而提高膜的疏水性,采用非溶剂致相分离法,以水作为非溶剂添加剂,希望通过调节初生膜的预蒸发时间这一最便捷的手段,调控膜的结构及疏水性.结果表明,随着预蒸发时间的延长,铸膜液黏度增加,有利于膜表面凝胶化的形成,从而在膜表面构建出均一超疏水结构.当预蒸发时间达到120 s时,膜表面的水接触角达到151.2°,膜的气体渗透通量为40.9 mL/(m~2·s·Pa),透水压力达到65.3 kPa.     

壳聚糖-聚磷酸钠聚离子复合物渗透汽化膜研究(Ⅱ)聚合条件和操作条件对膜分离性能的影响

选用聚阳离子电解质壳聚糖和聚阴离子电解质聚磷酸钠为膜材料，采用聚离子复合反应的方法制备出了一种新型的渗透汽化透水膜：壳聚糖—聚磷酸钠复合物膜(CS—SPP)，通过控制聚离子反应的条件如聚磷酸钠浓度，反应时间，从而改变聚离子反应程度，制备出了不同性能的聚离子膜．研究了壳聚糖-聚磷酸钠聚离子膜分离乙醇／水溶液的特性，探讨了聚离子反应条件、操作条件对膜分离性能的影响．     

聚偏氟乙烯膜的研究进展

探讨和介绍了聚偏氟乙烯(PVDF)微孔膜、超滤膜、共混膜和改性膜近来的研究情况，提出开发高性能的疏水性微孔膜和小孔径亲水性超滤膜，并解决亲水性PVDF膜的耐污染问题，成为PVDF膜的主要研究方向、     

Increased water retention in polymer electrolyte membranes at elevated temperatures assisted by capillary condensation

We establish a new systematic methodology for controlling the water retention of polymer electrolyte membranes. Block copolymer membranes comprising hydrophilic phases with widths ranging from 2 to 5 nm become wetter as the temperature of the surrounding air is increased at constant relative humidity. The widths of the moist hydrophilic phases were measured by cryogenic electron microscopy experiments performed on humid membranes. Simple calculations suggest that capillary condensation is important at these length scales. The correlation between moisture content and proton conductivity of the membranes is demonstrated.     

Hydrophilic and hydrophobic interactions in cross-linked chitosan membranes

Chitosan membranes with different cross-linking density were prepared by modifying cross-linking time. Sodium tripolyphosphate was the cross-linking agent. A pulsed nuclear magnetic resonance study was performed on uncross-linked and cross-linked membranes. Different fraction of water molecules were identified in different zones within the membranes. The ratio of water molecules per chitosan repeating unit were calculated. A maximum of twelve water molecules were tightly coordinated to the chitosan repeating unit. Also, a very small water molecule fraction was identified but it was mobile enough as not to contribute to the dipolar interactions. The cross-linking reaction could lead to the formation of hydrophilic and hydrophobic interactions. These two types of interactions could result in the coexistence of a network formed by hydrophilic and hydrophobic micropores. This knowledge could be useful for the interpretation of results of hydrophobic drugs permeation across hydrophilic membranes. For example, the increment of estradiol fluxes across chitosan membranes with an increase in cross-linking density.     

In Vitro Passive and Iontophoretically Assisted Transport of Salbutamol Sulphate Across Synthetic Membranes

The passive and electrically assisted transport of salbutamol sulphate through four synthetic membranes was investigated. Two of these were hydrophilic (Visking 18/32 and Celgard-3401®) and two hydrophobic (Celgard-2400® and Celgard-4500®). Significant differences in passive membrane transport were observed. The hydrophilic Celgard membrane gave similar passive transport rates to Visking 18/32. However, slower rates were observed with the hydrophobic membranes, the rate for Celgard-4500 being 4-5 fold smaller than Visking 18/32 and that for Celgard-2400 being negligible over a period of 6 hours. The passive release of salbutamol sulphate from the hydrogel across the hydrophilic membranes was matrix-controlled, whereas the membrane was the rate-limiting element for passive release through the hydrophobic membranes. Application of an electrical potential giving rise to iontophoretic currents in the range 0.100 to 0.500 mA led to an increase in drug transport rate and this effect became larger as the current was increased. The quantity of drug transported in a given time period increased linearly with time for both kind of membranes. However the relative increase in transport induced by current was greatest with the hydrophobic membranes.     

In Vitro Passive and Iontophoretically Assisted Transport of Salbutamol Sulphate Across Synthetic Membranes

Abstract

The passive and electrically assisted transport of salbutamol sulphate through four synthetic membranes was investigated. Two of these were hydrophilic (Visking 18/32 and Celgard-3401®) and two hydrophobic (Celgard-2400® and Celgard-4500®). Significant differences in passive membrane transport were observed. The hydrophilic Celgard membrane gave similar passive transport rates to Visking 18/32. However, slower rates were observed with the hydrophobic membranes, the rate for Celgard-4500 being 4-5 fold smaller than Visking 18/32 and that for Celgard-2400 being negligible over a period of 6 hours. The passive release of salbutamol sulphate from the hydrogel across the hydrophilic membranes was matrix-controlled, whereas the membrane was the rate-limiting element for passive release through the hydrophobic membranes. Application of an electrical potential giving rise to iontophoretic currents in the range 0.100 to 0.500 mA led to an increase in drug transport rate and this effect became larger as the current was increased. The quantity of drug transported in a given time period increased linearly with time for both kind of membranes. However the relative increase in transport induced by current was greatest with the hydrophobic membranes.     

天然纤维粉体对PVDF/DMAc体系热力学及膜结构的影响

考察天然纤维粉体/聚偏氟乙烯(PVDF)/N,N-二甲基甲酰胺(DMAc)铸膜液热力学性质,采用浸没沉淀相转化法制备了天然纤维粉体/PVDF共混膜,表征了共混膜的结构和性质。结果表明,按照棉花粉体、羊毛粉体、无粉体的顺序,制膜体系越来越容易发生液固分相;并且棉花粉体/PVDF共混膜、羊毛粉体/PVDF共混膜、PVDF膜的孔隙率和水通量依次降低,结晶度依次增加,但膜形态一致,均为致密皮层和多孔亚层。共混膜性质的差异主要是由于纤维粉体亲水性的不同,添加亲水性较好的羊毛粉体的铸膜液成膜速度慢,而添加亲水性较低的棉花粉体的铸膜液成膜速度较快。     

耐污染膜—聚乙烯醇膜的研究进展

介绍了具有高度亲水性、良好耐污染性的膜材料－聚乙烯醇在ＲＯ、ＵＦ和ＭＦ领域中的应用,对近１０年来聚乙烯醇薄层复合膜和不对称膜的制备、性能和改性的进展情况进行了综述。     

低温等离子体液相接枝NVP改性PAN膜

采用液相等离子体接枝技术改性聚丙烯腈(PAN)膜,在PAN膜表面引入亲水性单体氮乙烯吡咯烷酮(NVP).通过傅立叶红外光谱、DSC、XPS对PAN改性膜进行了表征,研究了单体浓度、温度、接枝时间对PAN改性膜纯水通量的影响,考察了在不同单体接枝温度下,PAN改性膜对NaCl、MgSO4混合盐体系的分离性能.     

聚醚砜超滤膜的亲水化改性研究进展

聚醚砜(PES)超滤膜的疏水性导致在处理水的过程中驱动力高、易污染，需要亲水化改性．调研了PES超滤膜的亲水化改性方法：物理共混、化学共聚、表面物理吸附、表面化学处理、表面接枝等．围绕亲水化综述了PES超滤膜亲水改性的研究进展．     

聚丙烯微孔膜亲水改性及其对力学性能影响的研究进展

聚丙烯微孔膜因其比表面积大、性能优异、价格合理等优点而被广泛应用;但其亲水性差、易被污染,因此需要进行亲水改性。根据是否发生化学变化将亲水改性方法归纳为:物理法、化学法和物理化学法;改性之后膜的亲水性得到了改善。分类论述了各种亲水改性方法对聚丙烯微孔膜力学性能的影响及其对膜亲水性能的改善程度同时对亲水改性方法的改进进行了展望。