膜微滤强化技术国内研究进展

概述了国内膜微滤强化技术研究进展,分析了附加场、设置湍流促进器或脉动进料方法,以及旋转横流强化、旋转动态膜强化、组合强化等方法的特点。     

旋转切向流PA管式膜微滤试验研究

实验研究了旋转切向流聚丙烯PA管式膜微滤。通过建立的旋转切向流强化微滤实验装置系统，测定了旋转直线切向流和旋转圆弧切向流PA管式膜在不同SiO2悬浮液农度和不同流体压力下的膜通量随时间的变化曲线。实验研究结果表明，旋转切向流强化微滤不但节能，而且系统结构简单。     

旋转切向流管式膜器的参数设计与优化研究

旋转切向流强化膜微滤是近几年提出的一种新的强化方法 ,它把水力旋流器的作用原理引入到管式膜微滤中 ,从而改进了膜器结构和悬浮流体进入膜器的方式 ,提高了膜通量 ,降低了膜污染 ,本文分析和探讨了旋转切向流膜器的结构参数与操作参数 ,给出了膜器结构设计与优化方法     

具有旋转横流的管式膜微滤的渗透通量及环隙压力分布

用自行研制的计算机控制的在线管式膜器环隙压力测试系统实测分析了不同入口压力、不同悬浮液浓度和不同膜器环隙大小下的旋转横流膜微滤渗透通量大小及环隙压力分布规律,与一般横流膜微滤的环隙压力分布及渗透通量大小进行了对比,为进一步研究膜微滤强化机理、探讨减少或解决浓差极化和膜污染的方法提供了实测依据.     

动态Monte Carlo模拟蛋白质与微滤膜相互作用及其对微滤过程影响

构建了二维晶格蛋白质-微滤膜疏水相互作用模型，采用动态Monte Carlo方法模拟了微滤膜污染过程及其受膜孔径、蛋白质浓度和蛋白质结构特性等因素的影响。模拟结果显示：微滤过程中膜通量的变化呈现快速下降、缓慢下降和平台期3个阶段。小孔径微滤膜的滤阻从以膜孔阻力为主转变为以饼层阻力为主;而大孔径微滤膜的滤阻则以膜孔阻力为主。提高蛋白质浓度会强化滤阻从膜孔阻力向饼层阻力的转变。在微滤过程中，蛋白质会因疏水相互作用在膜孔内发生构象转换，进而发生不可逆吸附并形成多层堆积，导致膜污染和通量下降，提高蛋白质的构象稳定性可以显著降低其对微滤膜的污染。分子模拟结果与文献报道的实验结果和理论模型相符，所提供的微观信息对于微滤过程优化和微滤膜设计具有参考作用。     

超声强化多通道陶瓷膜微滤超细TiO2悬浮液

针对超声强化膜分离过程能耗高的问题,提出并设计了一种新型超声强化膜分离操作方式,并进行了超声强化陶瓷膜微滤超细TiO₂颗粒悬浮液的研究。考察了超声场参数、操作时间及溶液环境对多通道陶瓷膜微滤过程的影响规律,并分析了此操作方式强化陶瓷膜微滤颗粒悬浮体系的机理。结果表明,该操作方式能够获得较高膜通量恢复率及平均膜通量,同时超声能量消耗减小了90.0%以上;降低超声频率及提高功率,有利于膜通量恢复,在超声参数45 kHz和0.33 W·cm^-2条件下,膜通量恢复到初始值的94.0%;控制超声辐射时间0.167 min,微滤时间8 min时,平均膜通量提高了61.5%;降低悬浮液颗粒浓度及提高料液温度都有利于超声场强化陶瓷膜微滤过程。     

旋转流强化管式膜微滤的研究评述

浓差极化和膜污染是阻碍微滤广泛应用的关键难题 ,在认识理解颗粒迁移沉积和过滤速率下降的基础上 ,本文对旋转流管式膜微滤进行了一定的探讨分析。     

旋转流强化膜过滤的研究与应用

通过流场测定 ,探明了旋转流膜过滤器内的流态全貌 ,为认识旋转流强化膜过滤的机理与膜器设计提供了理论依据。建立了旋转流膜微滤通量数学模型 ,探明了渗透通量的三个主要影响因素。应用研究证明 ,此种膜器是一种结构不复杂、通量大、分离质量好、能量利用率高的新颖膜器结构 ,其应用前景十分宽广。     

Mg（ClO4）2填充聚丙烯晴微滤膜的制备及性能研究

以高氯酸镁(Mg(ClO4)2)为添加剂,采用浸没沉淀相转化法制备了聚丙烯晴(PAN)微滤平板膜。考察了Mg(ClO4)2含量对PAN微滤平板膜纯水通量、膜污染速率、孔隙率、接触角和膜表面形态的影响;并根据相关结论探讨了PAN微滤平板膜抗膜污染主要物质SMP的特性试验。结果表明,PAN微滤平板膜中添加Mg(ClO4)2可改变成膜性能,当Mg(ClO4)2的质量分数为1.5%时,PAN微滤平板膜的成膜性能最优,抵抗强疏水性有机物组分污染的能力增强。     

旋转管式微滤器中流体流动对过滤通量的影响

为讨论膜器环隙内流体流动对过滤通量的影响，运用了纳维—斯托克斯方程、连续性方程、达西定律等，并结合稳定性理论，分别对主流体为去离子水和悬浮液的情况下环隙内流体的运动规律进行了分析。对于主流体为去离子水的情况，建立了过滤通量与膜器进出口压力降的关系，并与Belfort的实验数据进行了比较。结果证明当主流体为去离子水时(即无滤饼生成的理想情况下)，流体旋转所产生的离心力对微滤推动力有削弱作用，当内膜管转速较小时，流体流动方式对过滤通量几乎无影响。对于悬浮液，由内膜管旋转所形成的剪切力对减少滤饼形成的作用甚微，而Taylor涡的形成是强化微滤的主要原因。最后提出了内膜管旋转管式膜器优化设计的新思想。     

膜分离法污水处理技术

介绍了膜分离技术及其特点，回顾了膜分离技术及其在污水处理领域中的应用发展概况；详细分析了电渗析、微滤、超滤、反渗透和纳滤五种膜分离技术和它们在污水处理领域中的应用开发现状以及存在的问题；还概括了膜分离技术（包括膜制备、膜组件和膜工艺）中最新应用开发动向，并对膜分离技术在污水处理领域中的应用前景作了展望。可以预计，本世纪膜分离技术将得到迅速的发展，在污水处理领域发挥极其重要的作用。     

Binding and Fusion of Extracellular Vesicles to the Plasma Membrane of Their Cell Targets

Exosomes and ectosomes, extracellular vesicles of two types generated by all cells at multivesicular bodies and the plasma membrane, respectively, play critical roles in physiology and pathology. A key mechanism of their function, analogous for both types of vesicles, is the fusion of their membrane to the plasma membrane of specific target cells, followed by discharge to the cytoplasm of their luminal cargo containing proteins, RNAs, and DNA. Here we summarize the present knowledge about the interactions, binding and fusions of vesicles with the cell plasma membrane. The sequence initiates with dynamic interactions, during which vesicles roll over the plasma membrane, followed by the binding of specific membrane proteins to their cell receptors. Membrane binding is then converted rapidly into fusion by mechanisms analogous to those of retroviruses. Specifically, proteins of the extracellular vesicle membranes are structurally rearranged, and their hydrophobic sequences insert into the target cell plasma membrane which undergoes lipid reorganization, protein restructuring and membrane dimpling. Single fusions are not the only process of vesicle/cell interactions. Upon intracellular reassembly of their luminal cargoes, vesicles can be regenerated, released and fused horizontally to other target cells. Fusions of extracellular vesicles are relevant also for specific therapy processes, now intensely investigated.     

Fake It ‘Till You Make It—The Pursuit of Suitable Membrane Mimetics for Membrane Protein Biophysics

Membrane proteins evolved to reside in the hydrophobic lipid bilayers of cellular membranes. Therefore, membrane proteins bridge the different aqueous compartments separated by the membrane, and furthermore, dynamically interact with their surrounding lipid environment. The latter not only stabilizes membrane proteins, but directly impacts their folding, structure and function. In order to be characterized with biophysical and structural biological methods, membrane proteins are typically extracted and subsequently purified from their native lipid environment. This approach requires that lipid membranes are replaced by suitable surrogates, which ideally closely mimic the native bilayer, in order to maintain the membrane proteins structural and functional integrity. In this review, we survey the currently available membrane mimetic environments ranging from detergent micelles to bicelles, nanodiscs, lipidic-cubic phase (LCP), liposomes, and polymersomes. We discuss their respective advantages and disadvantages as well as their suitability for downstream biophysical and structural characterization. Finally, we take a look at ongoing methodological developments, which aim for direct in-situ characterization of membrane proteins within native membranes instead of relying on membrane mimetics.     

多孔陶瓷膜支撑体的制备研究进展

多孔陶瓷膜支撑体是陶瓷膜制备与应用的基础.本文概述了多孔陶瓷膜支撑体主要的制备工艺及其特点;探讨了制备过程中影响多孔陶瓷膜支撑体结构及性能的因素;综述了多孔陶瓷膜支撑体研究现状,并对多孔陶瓷膜支撑体的发展趋势进行了展望.     

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。     

Steroid‐Based Amphiphiles for Membrane Protein Study: The Importance of Alkyl Spacers for Protein Stability

Membrane proteins allow effective communication between cells and organelles and their external environments. Maintaining membrane protein stability in a non‐native environment is the major bottleneck to their structural study. Detergents are widely used to extract membrane proteins from the membrane and to keep the extracted protein in a stable state for downstream characterisation. In this study, three sets of steroid‐based amphiphiles—glyco‐diosgenin analogues (GDNs) and steroid‐based pentasaccharides either lacking a linker (SPSs) or containing a linker (SPS‐Ls)—have been developed as new chemical tools for membrane protein research. These detergents were tested with three membrane proteins in order to characterise their ability to extract membrane proteins from the membrane and to stabilise membrane proteins long‐term. Some of the detergents, particularly the SPS‐Ls, displayed favourable behaviour with the tested membrane proteins. This result indicates the potential utility of these detergents as chemical tools for membrane protein structural study and a critical role of the simple alkyl spacer in determining detergent efficacy.     

用集成膜技术回收无机氨氮废水的研究进展

首次提出用电去离子膜技术处理高浓度无机氨氮废水。介绍了近年来用反渗透、电渗析和电去离子等膜技术及其集成膜技术回收无机氨氮废水的进展,分析了在这种工程应用中各种膜技术的特点。该废水处理系统实现闭路循环,同时回收纯水和无机铵盐,既节能又减排,经济和环境效益极好。     

多孔陶瓷膜反应器用于非均相超细纳米催化的研究进展(英文)

Heterogeneous catalysts with ultrafine or nano particle size have currently attracted considerable attentions in the chemical and petrochemical production processes, but their large-scale applications remain challenging because of difficulties associated with their efficient separation from the reaction slurry. A porous ceramic membrane reactor has emerged as a promising method to solve the problem concerning catalysts separation in situ from the reaction mixture and make the production process continuous in heterogeneous catalysis. This article presents a review of the present progress on porous ceramic membrane reactors for heterogeneous catalysis, which covers classification of configurations of porous ceramic membrane reactor, major considerations and some important industrial applications. A special emphasis is paid to major considerations in term of application-oriented ceramic membrane design, optimization of ceramic membrane reactor performance and membrane fouling mechanism. Finally, brief concluding remarks on porous ceramic membrane reactors are given and possible future research interests are also outlined.     

Chemical modification of polyethersulfone nanofiltration membranes: A review

Polysulfone (PS) and poly(ether)sulfone (PES) are often used for synthesis of nanofiltration membranes, due to their chemical, thermal, and mechanical stability. The disadvantage for applying PS/PES is their high hydrophobicity, which increases membrane fouling. To optimize the performance of PS/PES nanofiltration membranes, membranes can be modified. An increase in membrane hydrophilicity is a good method to improve membrane performance. This article reviews chemical (and physicochemical) modification methods applied to increase the hydrophilicity of PS/PES nanofiltration membranes. Modification of poly(ether)sulfone membranes in view of increasing hydrophilicity can be carried out in several ways. Physical or chemical membrane modification processes after formation of the membrane create more hydrophilic surfaces. Such modification processes are (1) graft polymerization that chemically attaches hydrophilic monomers to the membrane surface; (2) plasma treatment, that introduces different functional groups to the membrane surface; and (3) physical preadsorption of hydrophilic components to the membrane surface. Surfactant modification, self‐assembly of hydrophilic nanoparticles and membrane nitrification are also such membrane modification processes. Another approach is based on modification of polymers before membrane formation. This bulk modification implies the modification of membrane materials before membrane synthesis of the incorporation of hydrophilic additives in the membrane matrix during membrane synthesis. Sulfonation, carboxylation, and nitration are such techniques. To conclude, polymer blending also results in membranes with improved surface characteristics. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

反渗透膜法处理城市污水技术的探析

介绍了反渗透膜分离技术及其特点，讨论了反渗透膜分离技术在城市污水处理领域中的重要作用。