酸化碳纳米管/聚酰亚胺混合基质膜的制备及气体分离性能研究

以4,4’-(六氟异丙基)二酞酸酐(6FDA)和2,6-二氨基甲苯(2,6-DAT)为原料,合成6FDA-2,6DAT型聚酰亚胺,通过引入酸化碳纳米管(MWCNTs-COOH)填料,利用热致相分离法制备了酸化碳纳米管/聚酰亚胺(MWCNTs-COOH/PI)型混合基质膜(MMMs)。通过红外光谱(FT-IR)、扫描电镜(SEM)、X-射线衍射(XRD)及气体渗透仪对混合基质膜的结构和性能进行了表征和分析,并考察了不同掺杂量的酸化碳纳米管对混合基质膜的二氧化碳分离性能影响。结果表明,MWCNTs-COOH的一维光滑孔道结构与聚合物间形成的非贯穿孔状缺陷可以为气体的传输提供了高速通道,显著增强了气体的渗透性;其次,填料的表面官能团可以增强对CO2的吸附选择性,从而提高了混合基质膜的CO2分离性能。相比于纯聚酰亚胺膜,MWCNTs-COOH掺杂量为2.0wt%的混合基质膜的二氧化碳渗透系数88.28 Barrer、二氧化碳/甲烷选择性为52.45、二氧化碳/氮气选择性为28.64,分别提高了128.08%、43.65%和35.58%。     

GO-TSC/聚酰亚胺混合基质膜的制备及气体分离性能研究

使用氨基硫脲（TSC）对氧化石墨烯（GO）进行改性,制备GO-TSC层状复合材料。随后,将该复合材料加入到Matrimid^®5218（PI）基质中,制备用于二氧化碳分离的混合基质膜（MMMs）。通过TGA、SEM及气体分离性能测试考察了GO-TSC对膜热稳定性、结构和气体分离性能等的影响。SEM结果显示GO-TSC可均匀分散在聚合物基质上并与基质紧密结合;TGA结果显示混合基质膜在250 ℃以上仍保持稳定。与纯PI膜相比,MMMs显著增强了二氧化碳的渗透性。GO-TSC中所含的氨基与二氧化碳具有良好的亲和力,增加的碱性位点可以有效地转运二氧化碳。GO-TSC的层状结构增加了气体的传输路径,不利于大动态直径气体（甲烷、氮气）的通过,从而提高了分离性能。GO-TSC负载量为0.75%（质量分数）时混合基质膜的分离性能最佳。相比较纯PI膜,混合基质膜的二氧化碳渗透系数和二氧化碳/甲烷、二氧化碳/氮气分离系数分别提高了42.16%、95.79%和83.72%。     

MOF基混合基质气体分离膜界面作用调控研究进展

混合基质膜结合了无机填充材料和聚合物组分的双重优势,被认为是一种可同时增加渗透性和选择性的新型方法,有望解决传统聚合物膜的Trade-off效应。混合基质膜的气体分离性能主要依赖无机填充材料的分子筛分性质和高分子本身的化学结构,因此适当选择无机填充材料对于制备高性能的混合基质膜十分重要。金属有机骨架(MOF)作为一种新型多孔填料,具有比表面积大、密度小、孔隙率高和孔尺寸可调等优点,因此在气体吸附分离和气体储存等领域应用广泛,为新型混合基质膜带来良好的发展机遇。但混合基质膜的分离性能并不是简单地两相性能相加,在大多数情况下分离性能远低于材料模拟的预测理论值,造成这种非理想性的关键因素之一是MOF晶体和聚合物之间的界面缺陷,这可能导致界面非选择性空隙的形成、聚合物硬化和孔隙堵塞等界面问题,降低膜的分离性能。因此,实现MOF-聚合物基质间的界面作用调控以改善界面相容性是充分发挥MOF基混合基质膜气体分离潜力的关键。本工作综述了MOF基混合基质膜近五年关于不同类型界面作用调控的方法及策略,及其对气体分离性能的影响。最后,总结构建的界面作用对于混合基质膜性能的正面影响并提出当中存在的问题,为混合...     

IL@ZnBDC/PI混合基质膜的制备及CO2分离性能研究

选取咪唑型离子液体修饰金属有机框架填料ZnBDC制备IL@ZnBDC纳米复合填料,通过物理共混的方式将其引入PI中制备PI-IL@ZnBDC混合基质膜。结果表明,复合填料的引入改善了填料与PI间的相容性,增加了混合基质膜的分子链间距,强化了膜内CO₂扩散过程。同时,离子液体中含有与CO₂有较强亲和作用的三氟甲基、磺酸基团和咪唑基团,促进了CO₂在膜内的溶解,进而协同强化了PI-IL@ZnBDC混合基质膜的溶解-扩散机制,提升了CO₂气体通量和选择性。相较于纯PI膜,PI-IL@ZnBDC-2膜表现出优异的气体分离性能,CO₂的渗透系数为10.97 Barrer, CO₂/CH₄的选择性为42.21,分别较纯膜提升了59.9%和41.5%。     

气体分离无机膜的应用及研究进展

阐述了无机膜的优缺点及其在气体分离方面的研究与应用进展,并对无机膜发展中存在和尚待解决的问题作了简要评述。     

面向CO2分离的混合基质膜研究进展

CO₂分离膜技术是有效减少温室气体排放和能源气体净化的重要手段。设计制备新型混合基质膜(Mixed matrix membranes, MMMs)是同时提高膜的渗透性和选择性的有效途径。MMMs在多种膜分离材料中表现出了优异的CO₂分离性能,并且其具有潜在的克服trade-off效应的前景,因此被研究者广泛关注。MMMs中的填充剂对其分离性能起到至关重要的作用。首先介绍了MMMs中CO₂的传递机制,从传统型填充剂和新型填充剂入手,总结了近年来MMMs中不同种类的填充剂在膜基质中起到的作用以及对CO₂分离性能影响的研究进展。最后,对MMMs用于CO₂分离未来的发展进行了展望。     

炭膜气体分离性能研究

以酚醛树脂为原料制备了炭支撑膜和炭－炭复合膜，研究了其气体分离性能。结果表明：炭支撑膜分离气体和机理包括努森扩散和粘性流；采用浸涂－干燥－炭化的工艺制备的炭－炭复合膜对Ｈ２／ＣＯ２具有较好的分离性能，Ｈ２／ＣＯ２分离系数达５．６，大于理想努森扩散的分离系数３．７。但在高压差时复合膜上ＣＯ２的表面扩散增强，使Ｈ２／ＣＯ２分离系数下降。     

金属有机框架/聚酰亚胺混合基质膜的研究进展

聚酰亚胺是一种具有高热稳定性和良好成膜性的高分子材料,但聚酰亚胺膜在气体分离方面的应用效果较差。金属有机框架材料在气体分离中有较好的应用前景。用两者制备的混合基质膜,可以综合其各自的优点,提高对气体的选择渗透性。本文综述了采用金属有机框架材料、金属有机框架材料改性以及添加其他聚合物基底制备混合基质膜,对气体分离效果的影响,并对这种混合基质膜在气体分离领域的使用效果进行了分析,对这种混合基质膜面临的挑战进行了讨论与展望。     

Size effects of graphene oxide on mixed matrix membranes for CO2 separation

Graphene oxide (GO)‐polyether block amide (PEBA) mixed matrix membranes were fabricated and the effects of GO lateral size on membranes morphologies, microstructures, physicochemical properties, and gas separation performances were systematically investigated. By varying the GO lateral sizes (100–200 nm, 1–2 μm, and 5–10 μm), the polymer chains mobility, as well as the length of the gas channels could be effectively manipulated. Among the as‐prepared membranes, a GO‐PEBA mixed matrix membrane (GO‐M‐PEBA) containing 0.1 wt % medium‐lateral sized (1–2 μm) GO sheets showed the highest CO₂ permeation performance (CO₂ permeability of 110 Barrer and CO₂/N₂ mixed gas selectivity of 80), which transcends the Robeson upper bound. Also, this GO‐PEBA mixed matrix membrane exhibited high stability during long‐term operation testing. Optimized by GO lateral size, the developed GO‐PEBA mixed matrix membrane shows promising potential for industrial implementation of efficient CO₂ capture. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2843–2852, 2016     

Hydrophobic inorganic membranes for water/gas separation

Macroporous or mesoporous hydrophobic inorganic membranes are prepared by a simple one-pot synthesis method coupling the sol–gel process with fluorinated silanes as precursors and the use of alumina powders as fillers. The porosity of these intrinsically hydrophobic membranes can be tuned by the particle size distribution of the dispersed alumina powder. These membranes developed for water/gas separation applications are characterized in term of gas permeance and water breakthrough pressure. A value of air permeance equal to 1800 L min⁻¹ bar⁻¹ m⁻² associated with a water breakthrough pressure larger than 10 bar are measured for the effective sample.     

膜接触器分离气体研究进展

阐述了膜接触器分离气体的基本原理和组件设计,讨论了膜材料、吸收剂和流动方式的选择,列举了一些商业膜接触器。最后对膜接触器分离低浓度CO2气体的研究进行了展望。     

Enhanced gas separation properties by using nanostructured PES‐Zeolite 4A mixed matrix membranes

The polymer–zeolite mixed matrix membranes were fabricated by incorporating nanosized or microsized zeolite 4A into polyethersulfone. A comparison of zeolite 4A nanocrystals and microcrystals was made by using SEM, XRD, N₂ adsorption–desorption measurements. Zeolite particles were well‐distributed in the polymer phase, as reflected by the SEM images. The effects of the zeolite 4A particle size on the gas permeation performance were studied. Experimental results demonstrate that mixed matrix membranes exhibit decreased gas permeabilities due to the barrier effect of zeolite particles. The obtained permselectivity is greatly enhanced for He/N₂, H₂/N₂, He/CO₂, and H₂/CO₂ gas pairs, especially for nanosized zeolite 4A mixed matrix membranes. The gas permeation performance difference is observed between the nanostructured and microstructured membranes, which is attributed to a combined effect of different zeolite composition and different particle size. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3800–3805, 2006     

Fabrication of Pebax/SAPO mixed matrix membranes for CO2/N2 separation

Mixed matrix membranes (MMMs) were prepared by solvent evaporation method using Pebax-1074 polymer as matrix and inorganic zeolite SAPO-23 as dopant. The morphology, surface functional groups, microstructure, thermal stability, and separation performance of MMMs were analyzed by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, and gas permeation, respectively. The effects of dopant loading amount, permeation temperature, and permeation pressure on the structure and properties of MMMs were investigated. The results showed that the introduction of SAPO zeolite reduced the crystallinity of the MMMs and improved the CO₂/N₂ selectivity. Under the conditions of 30°C and 0.15 MPa, the MMMs prepared by incorporating with 5% SAPO zeolite in content exhibited the highest CO₂/N₂ selectivity of 72.0 together with the CO₂ permeability of 98.2 Barrer.     

Recent advances on mixed matrix membranes for CO2 separation

Recent advances on mixed matrix membrane for CO2 separation are reviewed in this paper. To improve CO2 separation performance of polymer membranes, mixedmatrixmembranes (MMMs) are developed. The concept of MMM is illustrated distinctly. Suitable polymer and inorganic or organic fillers for MMMs are summarized.Possible interface morphologies between polymer and filler, and the effect of interface morphologies on gas transport properties of MMMs are summarized. The methods to improve compatibility between polymer and filler are introduced. There are eightmethods including silane coupling, Grignard treatment, incorporation of additive,grafting, in situ polymerization, polydopamine coating, particle fusion approach and polymer functionalization. To achieve higher productivity for industrial application,mixed matrix composite membranes are developed. The recent development on hollow fiber and flat mixedmatrix composite membrane is reviewed in detail. Last, the future trend of MMM is forecasted.     

高性能气体分离聚苯胺膜

系统论述了聚苯胺自支撑膜和复合膜对气体的分离性能。聚苯胺自支撑膜、聚苯胺 /尼龙、聚苯胺 /氧化铝复合膜经去掺杂尤其是二次掺杂后 ,气体分离系数会显著提高 ,而透气系数略有提高。二次掺杂态聚苯胺自支撑膜和复合膜都具有极高的氧氮分离性能 ,已超过了一般聚合物材料的上限 ,最优异的聚苯胺膜的氧氮选择分离系数可达 30 ,它在包括有高选择性能膜材料聚酰亚胺、聚吡咙、聚三唑等在内的所有聚合物膜中排行第一 ,对空气分离显示出极大优势。预计聚苯胺复合膜及纳米膜在医疗保健等领域具有很大应用潜力     

Zeolite imidazolate framework (ZIF)-based mixed matrix membranes for CO2 separation: A review

Mixed matrix membranes (MMMs), which combine the good separation performance of inorganic materials with the low cost of polymers, have emerged as a research hotspot for gas separation membranes. Zeolite imidazolate frameworks (ZIFs) are widely used as fillers to prepare MMMs owing to their advantageous characteristics, such as adjustable pore channels, unsaturated sites, and easy functionalization. For MMMs, three directions can be employed as criteria for improvement compared with pristine polymeric membranes. In this article, the progress of ZIF-based MMMs is reviewed from the aspects of sole-ZIF-based MMMs and modified ZIF-based MMMs. Both strategies improve the separation performance through different improvement directions and mechanisms. Our analysis shows that the synergistic effect of the modified filler can change the structure of the membranes, such as by improving the filler–polymer interface voids, which provides a foundation to overcome the trade-off effect to a certain extent. © 2020 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48968.