Tailoring the Separation Behavior of Hybrid Organosilica Membranes by Adjusting the Structure of the Organic Bridging Group

Hybrid organically linked silica is a highly promising class of materials for the application in energy‐efficient molecular separation membranes. Its high stability allows operation under aggressive working conditions. Herein is reported the tailoring of the separation performance of these hybrid silica membranes by adjusting the size, flexibility, shape, and electronic structure of the organic bridging group. A single generic procedure is applied to synthesize nanoporous membranes from bridged silsesquioxane precursors with different reactivities. Membranes with short alkylene (CH₂ and C₂H₄) bridging groups show high H₂/N₂ permeance ratios, related to differences in molecular size. The highest CO₂/H₂ permeance ratios, related to the affinity of adsorption in the material, are obtained for longer (C₈H₁₆) alkylene and aryl bridges. Materials with long flexible alkylene bridges have a hydrophobic surface and show strongly temperature‐dependent molecular transport as well as a high n‐butanol flux in a pervaporation process, which is indicative of organic polymerlike properties. The versatility of the bridging group offers an extensive toolbox to tune the nanostructure and the affinity of hybrid silica membranes and by doing so to optimize the performance towards specific separation challenges. This provides excellent prospects for industrial applications such as carbon capture and biofuel production.     

γ－Al_2O_3超滤膜分离层活性孔孔径分布测定研究

基于毛细管冷凝机理，改进了蒸汽渗透法（ｐｅｒｍｐｏｒｏｍｅｔｒｙ），并实验测定了γ－Ａｌ２Ｏ３非对称超滤膜分离层的孔径分布．研究了环己烷和四氯化碳两种冷凝介质对测定结果的影响，并与氮气吸附－脱附法测定结果进行了比较．结果表明：改进的蒸汽渗透法具有装置简单、适于测定纳米级超滤膜孔径分布、结果可靠及重复性好等优点     

用PVA／PAN复合膜分离乙醇水溶液

简述了ＰＶＡ／ＰＡＮ复合膜的研制过程，分析了影响膜性能的主要因素，摸索了制膜条件。     

用于渗透汽化过程的中空纤维膜器工艺流程设计模型

本文通过渗透汽化过程中物料，热量衡算，进行合理假设，建立工艺流程设计的数学模型，为中空纤维膜器在渗透气化过程应用提供设计依据，并以生产无水乙醇为例求解出数学模型。     

海藻酸钠与PVA共混膜用于渗透汽化分离乙醇┐水混合物

制备了天然高分子海藻酸钠与ＰＶＡ的不同比例共混膜，并用于渗透汽化法分离乙醇－水混合物。结果表明，与均质ＰＶＡ膜相比，透过系数及分离系数均大幅度提高，尤其是当乙醇浓度低于８０％时，共混膜依然保持较高分离系数，在共混膜中，ＰＶＡ可起到增强力学强度，易于交联的作用。     

Computer simulation and comparative study on the pervaporation separation characteristics of sodium alginate and its blend membranes with poly(vinyl alcohol) to separate aqueous mixtures of 1,4‐dioxane or tetrahydrofuran

A comparative study on the pervaporation separation has been attempted for water + 1,4‐dioxane and water + tetrahydrofuran mixtures using sodium alginate and blend membranes of sodium alginate with 5, 10, and 20 mass % of poly(vinyl alcohol). Pure sodium alginate membrane has a selectivity of 111 to water at 0.35‐mol fraction of water in the feed mixture containing 1,4‐dioxane while for water + tetrahydrofuran mixture, the membrane selectivity to water was 291 at 0.31‐mol fraction of water in the feed mixture. Pervaporation results have been discussed using the solution–diffusion principles. Arrhenius activation parameters for diffusion and permeation have been computed from the temperature‐dependent pervaporation results. Furthermore, experimental results have been analyzed using the complete mixing and plug flow models to compute membrane area as well as design parameters that are useful in scale‐up operations. The plug flow model is more appropriate than the complete mixing model to analyze the pervaporation results. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1827–1840, 2004     

渗透蒸发与化学反应耦合过程的研究（Ⅱ）：模型验证

针对乙酸异戊酯合成反应体系，采用改性的ＰＡｍＡ－ＰＩ渗透蒸发膜进行渗透蒸发与化学反应耦合过程的试验研究．在给定的实验条件下，可以回归出如下数学模型：η＝０．５１５５ｅｘｐ（７５０．５ＲＴ）ｌｎ［１＋７７０．０Ｃ２Ａｏｅｘｐ（－６４４８ＲＴ）（１－ε）（Π－ε）－１４．５５ｅｘｐ（－５９２．２ＲＴηε２Ｃ２Ａｏ］／ＣＡｏε它能较准确地描述渗透蒸发与乙酸异戊酯合成反应过程，在相似反应条件下，可以预测改变其它变量的变化趋势，从而给渗透蒸发膜反应器的优化设计提供了理论依据     

Characterization and preparation of polyion complex composite membranes for the separation of methyl tert‐butyl ether/methanol mixtures

A series of polyion complex (PIC) composite membranes composed of sodium alginate (SA) polyanion and chitosan polycation were prepared by varying the ratio of concentration. The interaction between SA and chitosan was investigated by FTIR, SEM, and X‐ray analysis and was related to mechanical properties and the swelling phenomenon. The overall PIC composite membranes showed the following results: the total thickness of the coating layer was thicker than that of pure SA composite, and increased with increasing the concentration of chitosan solution during PIC formation. This result was attributed to the diffusion of chitosan molecules from the liquid solution into the SA matrix, and the incorporation with SA molecules. For the PIC membranes prepared with different concentrations of polymer solution, their structural differences could not be detected from IR spectra but their morphological differences could be noticeably found from SEM. Furthermore, the amorphousness of PIC membranes and their elongation properties at break increased significantly as a function of polymer contents, whereas the tensile modulus decreased because of the physical transition effect. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 714–725, 2002     

Pervaporation of tertiary butanol/water mixtures through chitosan membranes cross‐linked with toluylene diisocyanate

Membranes made from 84% deacetylated chitosan biopolymer were cross‐linked by a novel method using 2,4‐toluylene diisocyanate (TDI) and tested for the separation of t‐butanol/water mixtures by pervaporation. The unmodified and cross‐linked membranes were characterized by Fourier transform infra red (FTIR) spectroscopy, X‐ray diffraction (XRD) studies and sorption studies in order to understand the polymer–liquid interactions and separation mechanisms. Thermal stability was analyzed by differential scanning calorimetry (DSC) and thermo gravimetric analysis (TGA) while tensile strength measurement was carried out to assess mechanical strength. The membrane appears to have good potential for breaking the aqueous azeotrope of 88.2 wt% t‐butanol by giving a high selectivity of 620 and substantial water flux (0.38 kg m^?2 hr^?1). The effects of operating parameters such as feed composition, membrane thickness and permeate pressure on membrane performance were evaluated. Copyright © 2005 Society of Chemical Industry     

渗透汽化膜组件的结构特性

本文根据渗透汽化膜过程的特点,通过分析、计算、探讨了渗透汽化膜组件在结构上的特殊要求,这些要求与其它膜技术极不同,因此在渗透汽化膜组件及装置设计前,必须在实际料液操作条件下,进行长期试验,以取得设计数据和经验。