微管式固体氧化物燃料电池电解质膜的制备

基于聚合物溶液相分离诱导原理提出了一种新的微管式固体氧化物燃料电池（SOFC）电解质膜制备方法,应用该方法制得了YSZ电解质微管膜,该膜由致密电解质薄层和可制成电极的多孔层组成,其中YSZ致密电解质膜和多孔层厚度分别为3～5μm和70-90μm,而多孔层内表面孔隙率高于28．1％,电解质层和多孔层之间结合紧密,可避免电解质膜开裂或剥落等导致的电池性能降低等问题．该方法具有工艺简单、成本低、可靠性好等优点,为微管式SOFC电解质膜及电池的制备提供了一条新的途径．     

质子交换膜燃料电池模型研究进展

综述了质子交换膜燃料电池 (PEMFC)数学模型的研究进展 ,分析PEMFC中膜、催化层、扩散层和流场区域的传递现象和水、热管理的重要性 ,讨论了模型的维数、复杂性和求解方法 .提出了带有时间维数的PEMFC模型研究的实际应用意义     

两性离子基团改性分离膜的抗污染机理及研究进展

抗污染机理的研究对设计和合成抗污染膜材料具有指导意义。两性离子聚合物作为一种新型的抗污染膜材料逐渐受到人们的关注。本文从研究膜污染的成因及其影响因素出发,阐述了分离膜的抗污染机理及两性离子基团改性分离膜的抗污染特点,同时根据两性离子基团改性分离膜方式的不同,系统总结了近年来此类分离膜的研究进展,并对分离膜抗污染机理的研究和两性离子改性高分子分离膜未来的发展趋势作出展望。     

气体分离膜成膜技术及成膜机理的研究进展

介绍了气体分离膜的发展历史，从７０年代初期反渗透膜干燥技术获得气体分离膜，８０年代出现的“阻力型”“复合型”到９０年代发明的致密皮层非对称气体分离膜，着重介绍了成膜液相转化过程中发生微相分离的成膜机理，最后，提出现行成膜技术的不足及成膜机理的研究方向。     

膜的微波吸收机理

微波吸收现行理论将膜和材料混淆,把只能用于膜的反射损失(RL)性质用来表征材料,于是建立了错误的阻抗匹配理论和错误的膜吸收机理.阻抗匹配理论的不严谨表现为它有不同的定义,结果导致荒谬的结论如材料吸收的微波比进入材料的微波更多.这个事实说明阻抗匹配理论将孤立界面和在膜中的界面相混淆.阻抗匹配理论是建立在不可定义的物理量基础上的理论,存在严重缺陷.主流理论认为是材料本身具有多个吸收峰的性质导致(RL)有多个极小值.实际上均匀材料中的任何位置其微波吸收能力是一样的.微波在材料中传播的越远,被吸收的就越多,不会出现吸收峰.因而主流理论中膜的吸收峰又被错误地归结为材料的共振吸收.采用理论方法和自己实验室的实验数据,在波相消干涉的基础上建立了不同于当前主流理论的膜吸收机理并开拓性地应用了新理论.并指出文献报道的实验数据并不支持主流理论.同时通过已经发表的数据说明材料和膜的吸收机理不同,膜的吸收峰不是材料本身的属性,微波中的阻抗匹配理论应该用波的相消干涉理论取代.膜的多个吸收峰是膜特有的能量守恒所要求的、是角度效应的结果,需要用波的相消干涉分析,与材料的共振吸收没有任何关系.主流微波吸收理论混淆了实...     

木质素模型化合物的裂解工艺及机理的研究进展

化石资源的有限性、不可再生性及其利用所造成的环境污染,使木质生物质资源生产高附加值化学品和燃料受到广泛关注。因木质素是结构复杂的高分子聚合物,其综合有效利用受到极大限制,通常被作为燃料直接燃烧,同时给木质素解聚研究带来了巨大的困难。因此,围绕木质素模型化合物裂解工艺及机理的研究发展迅速。为梳理木质素模型化合物的裂解研究的现状和预测未来发展方向,本文综述了其裂解工艺和机理的研究进展。着重介绍木质素单体、二聚体和多聚体不同裂解工艺的特点、优势、应用前景以及相关的机理,最后预测了木质素模型化合物裂解研究未来的发展方向。     

微塑料环境赋存及其与有机污染物的作用机理研究进展

微塑料(MPs)普遍存在于全球各种环境介质中,可以吸附共存的污染物,尤其是有机污染物,进而改变其环境行为和毒性,也可以通过吸附/解吸作用促进污染物在不同介质中的迁移. MPs与有机污染物的吸附影响因素及其作用机理是准确评估MPs和有机污染物环境风险的必要信息.因MPs成分、结构、表面特征等的复杂性及其共存有机污染物的多样性使两者的相互作用十分复杂.本文对MPs在环境介质中的赋存、迁移、吸附有机污染物的影响因素及其相互作用机理进行了系统总结,以期为进一步评估MPs的环境行为和生态风险提供参考.     

纳滤膜的研究进展

纳滤膜是一种新型分离膜,其截流分子量介于反渗透膜和超滤膜之间,且对无机盐有一定的截流率。国内外纳滤膜制备方法有L-S相转化法、复合法、荷电化法和无机改性等。纳滤膜研究中存在着膜通量小、膜制作成本较高及抗污染性差等问题,因此选择和制备纳滤膜的材料,优化纳滤技术水处理工艺设计,提高纳滤性能,降低制膜成本,减轻膜污染等已成为当今科学研究的重要课题。     

功能性高分子微球在质子交换膜中的应用性能研究进展

不同拓扑结构和化学结构的高分子微球具有不同的物理化学特性与功能。本文介绍了功能高分子微球的设计、制备、与表征;总结了高分子微球作为功能性组份与质子传导性聚合物膜进行共混而制备了复合膜,作为质子交换膜的应用性能方面的研究进展,解决了质子交换膜的阻醇性能差和质子传递率低的关键问题。通过功能性高分子微球分散于质子传导性聚合物膜基质中,使得复合膜不但具有高的甲醇阻透性能,而且在低湿度下具有良好的保水性能,从而在质子传递性能方面发挥着重要作用。     

微孔聚丙烯中空纤维膜的研究与开发

综述了聚丙烯中空纤维膜的研究与开发状况 ,包括制备原理、过程、影响因素及应用开发状况。重点综述了聚丙烯中空纤维膜的制备及结构性能     

燃料电池用阴离子交换膜的研究进展

阴离子交换膜燃料电池(AEMFC)是一种高效环保的发电技术,因为其具有电池效率高、可以使用非贵金属(锌、镍)做为催化剂、优异的催化剂稳定性和灵活的燃料选择性等优点,而被视作新一代的能源动力系统。阴离子交换膜(AEM)是AEMFC电池结构中的重要组成部分,在其中起到隔绝燃料与氧化剂、传导氢氧根离子、支撑催化剂等作用。但是目前商业化的阴离子交换膜因为其离子导电率低、化学稳定性差而不适合于AEMFC方面的应用。因此,开发适于在AEMFC中使用的阴离子交换膜成为研究的热点。本文介绍了用于燃料电池的阴离子交换膜性能要求和功能化方法,同时还综述了近年来开发用于燃料电池应用的阴离子交换膜的研究进展。     

Microfiltration of amphoteric surfactant using ceramic membranes

The microfiltration of commercially available amphoteric surfactant using ceramic membranes has been investigated. Various combinations operating conditions such as pH, electrolyte and surfactant concentrations were employed. Zeta potential and adsorption isotherms were obtained for the components of membrane surfactant system as functions of pH using surfactant or indifferent electrolyte (KCl). The shift in the membrane isoelectric point induced by the surfactant is linked to the carboxylic groups present on the surfactant which are believed to play a dominant role in the net surface charge of the membrane. A minimum in the permeate flux was found at the pH corresponding to the isoelectric point of the zwitterionic surfactant. This behaviour is ascribed to the interactions occurring between the surfactant–surfactant molecules and the surfactant–membrane. The higher fluxes obtained at low pH as compared to high pH arise from different fouling mechanisms and ionic strengths. Lower fluxes were found when inorganic electrolytes were used in conjunction with surfactant. However, as the valency of the salt increases, flux behaviour of the zwitterionic surfactant (close to isoelectric point) does not vary whilst the cationic and anionic state of the surfactants are much more affected. Interactions between surfactant molecules as a result of the charge screening effects by the larger valence ions are encouraged. The permeate flux declines with an increasing surfactant concentration even though some concentrations fall under the critical micelle concentration (c.m.c.). This is attributed to concentration polarisation in which the accumulated surfactant concentration at the membrane surface could form a stable viscous phase which is resistant to permeate flow in the secondary layer next to the membrane surface. This paper demonstrates the role interactions such as surfactant–surfactant and surfactant–membrane play in influencing the filterability of surfactant solutions using ceramic membranes.     

Preparation and Evaluation of iPP/GO Microfiltration Membrane with Enhanced Antifouling Property

Isotactic polypropylene(iPP) and graphene oxide(GO), dispersed in dibutyl phthalate(DBP) and dioctyl phthalate(DOP), were blended to prepare organic-inorganic-blended microfiltration membranes using thermally induced phase separation(TIPS). These membranes were characterized by scanning electron microscopy(SEM), Fourier transform infrared spectroscopy(FTIR), contact angle measurements, mechanical properties, permeation tests, and porosity measurements. The morphology studied by SEM shows larger pores of the GO-blended membranes when compared to those of unmodified iPP membranes. Composite iPP/GO membranes achieve better performance in terms of water fluxes and pure water fluxes recovery ratio due to the hydrophilic nature of GO when compared with the pure iPP membranes. The addition of GO increases the permeability and the tensile strength by 352.98% and 123%, respectively, and also decreases the contact angle from 125° to 52.33°. We concluded that the composite membrane with 0.3% GO has the best antifouling ability of the membranes tested because it has the highest values of mean pore radius, porosity, and water flux observed in this study.     

A Combined Pore Blockage and Cake Filtration Model for Protein Fouling during Microfiltration

Previous studies of protein fouling during microfiltration have shown significant discrepancies between filtrate flux data and predictions of the classical pore blockage, pore constriction, and cake filtration models. A new mathematical model was developed for the filtrate flux which accounts for initial fouling due to pore blockage and subsequent fouling due to the growth of a protein cake or deposit over these initially blocked regions. The model explicitly accounts for the inhomogeneity in the cake layer thickness over different regions of the membrane arising from the time-dependent blockage of the pore surface. The model was shown to be in excellent agreement with experimental data obtained during the stirred cell filtration of bovine serum albumin solutions through polycarbonate track-etched microfiltration membranes over the entire course of the filtration. The model provides a smooth transition from the pore blockage to cake filtration regimes, eliminating the need to use different mathematical formulations to describe these two phenomena. In addition, the model provides the first quantitative explanation for some of the unusual observations reported previously in investigations of protein microfiltration. The results provide important insights into the underlying mechanisms of protein fouling during microfiltration. Copyright 2000 Academic Press.     

Drying Mechanism of Poly(N-isopropylacrylamide) Microgel Dispersions

The drying mechanism of poly(N-isopropylacrylamide) (pNIPAm) microgel dispersions was investigated. The microgels were synthesized by temperature-programmed aqueous free radical precipitation polymerization using NIPAm, N,N'-methylenebis(acrylamide), and water-soluble initiator. Drying processes of the microgel dispersions were observed with a digital camera and an optical microscope, and the resultant dried structures were observed by scanning electron microscopy. We found that the presence of the microgels changed the behavior of the drying process of water. In particular, the microgels were adsorbed at the air/water interface selectively within a few minutes irrespective of the microgel concentration. The relationship between the drying mechanism and structure of the resultant microgel thin film has been clarified by changing the microgel concentration of the dispersions.     

Effect of Contamination and Cleaning of a Microfiltration Membrane in Filtration of an Aqueous Extract of Dog-Rose

The main factors responsible for decrease in the filtration flux (membrane throughput) in removal of pectin substances from an aqueous extract from dog-rose fruits and reasons for membrane contamination were studied. The method for membrane cleaning with distilled water and additional cleaning agents, aqueous solutions of NaOH and HNO₃, was optimized.     

纳滤膜盐水溶液软化过程中膜面动态结垢机理研究进展

膜面结垢是纳滤(NF)膜盐水溶液软化过程中遇到的最主要问题之一。尽管已有大量的研究者对NF膜面结垢趋势预测和膜面污染物形貌的先进科学表征进行了深入广泛的研究,但对NF膜面动态结垢机制和过程还没有系统的报道。本文详细描述了包括膜阻力、浓差极化阻力、滤饼层阻力和膜孔堵塞阻力在内的NF膜结垢阻力理论模型;综述了包括膜面浓差极化、构晶离子成核和膜面结晶沉淀的NF膜面动态结垢过程的研究进展,重点阐述了表面结晶和主体结晶两种NF膜面结晶生长机制的研究概况,并展望了NF膜面结垢机理的研究前景。