聚离子液体二氧化碳分离膜材料的研究进展

近年来,全球二氧化碳排放超过370亿吨/年,对气候和自然环境造成严重影响,亟需发展碳捕集、利用与封存技术。气体膜分离是一种条件温和、操作简单的无相变分离技术,随着高渗透性、高选择性膜材料的不断涌现,逐渐成为全球碳捕集技术的主要发展方向。聚离子液体膜材料中含有大量高度亲和二氧化碳的功能基团,有望实现超高渗透选择性,被誉为下一代气体分离膜材料。综述了聚离子液体膜材料的研究进展,以渗透机制为主线重点介绍了面向碳捕集的阳离子型聚离子液体膜材料(主链型和支链型)的设计合成,包括阳离子和阴离子基团的选择,合成途径的选择,以及聚离子液体膜的结构设计优化。讨论了聚离子液体作为二氧化碳分离膜材料的优势和面临的挑战。     

离子液体膜材料分离二氧化碳的研究进展

离子液体由于具有不易挥发、结构可调、对CO₂有良好的吸收性能等特点而成为当前CO₂分离领域的研究热点,但因高黏度和高成本问题而限制了其工业化应用。将离子液体与气体分离膜材料结合,得到的新型分离膜材料兼具离子液体和膜的优势,成为当前离子液体研究领域的趋势之一。针对这一热点问题,综述了离子液体支撑液膜、聚离子液体膜和离子液体共混/杂化膜在CO₂分离方面的研究现状和进展,讨论了离子液体结构和含量对膜分离性能、稳定性等的影响。相关研究表明,离子液体共混/杂化膜具有较高的分离性能和稳定性,是一种很有应用前景的CO₂分离材料。提出该领域的重点发展方向,即开发新的功能化离子液体共混/杂化膜材料是解决高渗透通量与高稳定性之间矛盾、强化CO₂分离性能的有效途径,深入研究离子液体共混/杂化膜的形成机制、气体在膜中的渗透行为以及CO₂分离机理。     

离子液体中二氧化碳的溶解度研究进展

室温离子液体具有独特的气体选择溶解性,在二氧化碳(CO2)的捕集和分离中有很好的应用前景。综述了近年来CO2在不同离子液体中的溶解度研究进展,比较了CO2在常规离子液体和功能型离子液体中的不同溶解机制,分析、归纳了向离子液体中引入不同官能团对CO2溶解性能的影响规律,指出了离子液体捕集CO2的未来研究方向。     

功能化离子液体在二氧化碳吸收分离中的应用

吸收及分离二氧化碳是降低碳排放和应对全球气候变化的主要策略之一,这就必然要求全球科技工作者注重开发具有选择性高效吸收分离二氧化碳的新材料和新路线。作为近20多年来发展的一类代表性的新材料,离子液体（尤其是功能化离子液体）具有独特的物理化学性质,例如几乎没有蒸气压、液态温度范围大、热稳定性和化学稳定性好、电化学窗口宽、不可燃、结构-性质可调控等。这些性质使离子液体在二氧化碳吸收及分离领域受到广泛关注。重点综述了近5年（2015~2019）来功能化离子液体吸收分离二氧化碳的研究进展, 主要内容包括单位点离子液体、多位点离子液体、基于功能化离子液体的混合物、功能化离子液体杂化材料对二氧化碳的吸收分离。同时, 对目前该领域的发展所面临的主要问题和进一步的研究工作进行了分析讨论。     

离子液体支撑液膜应用研究进展

离子液体作为一种新型绿色介质,受到研究学者的广泛关注。离子液体具有不易燃、无味、无污染、无蒸汽压、可循环使用等独特性质,被广泛应用于化学化工过程中。离子液体用于膜分离技术具有不易挥发、稳定性好的特点,近来对离子液体在支撑液膜方面的研究备受关注,离子液体支撑液膜在污染性气体的吸收分离方面具有高选择性、高渗透性等优势,在有机物的分离方面具有分离效果明显、耐用性强等优势,在化学反应方面具有催化效率高、可循环使用等优势,本文介绍了离子液体支撑液膜的常用制备方法和膜基材料的选择,探讨了离子液体支撑液膜的稳定性和分离选择性的影响因素,对离子液体支撑液膜在气体分离、有机物的分离、化学反应等方面的应用研究进行了综述。     

支撑型离子液体膜用于捕集酸性气体研究

烟道气中酸性气体的捕集非常重要.近年来,支撑型离子液体膜(Supported ionic liquid membranes,SILMs)因传质速率高、稳定性好等特点而广泛应用于酸性气体的捕集研究.主要综述了利用离子液体作为膜液相来制备支撑液膜的方法,分析了捕集机理,讨论了离子液体阴阳离子结构、支撑体材料性能、原料气中水蒸汽、操作温度及跨膜压差等因素对支撑型离子液体膜渗透性及稳定性的影响,叙述了目前提高稳定性的一些方法,并在此基础上提出了支撑型离子液体膜用于酸性气体捕集需要解决的问题和工业化前景.     

离子液体分离膜及其在CO_2分离的应用研究进展

综述了离子液体支撑液膜、聚合离子液体膜、离子液体复合膜等的制备、性能及应用,重点介绍了离子液体分离膜在烟道气、水煤气转换(water-gas shift)、或沼气重组制氢(steam-methane reforming)、天然气(沼气)生产中分离CO_2的研究进展。     

离子液体分离膜及其在CO_2分离的应用研究进展

综述了离子液体支撑液膜、聚合离子液体膜、离子液体复合膜等的制备、性能及应用,重点介绍了离子液体分离膜在烟道气、水煤气转换(water-gas shift)、或沼气重组制氢(steam-methane reforming)、天然气(沼气)生产中分离CO_2的研究进展。     

离子液体在支撑液膜中的应用

简要叙述了利用离子液体作为膜液相来制备支撑液膜的方法,分析了影响支撑离子液体膜稳定性的主要因素.对支撑离子液体膜的应用情况做了详细综述,内容包括气体分离、有机混合物的分离以及化学反应等3个方面,并对其工业化前景进行展望.     

离子液体支撑液膜技术及其在气体分离中的研究进展

分析离子液体支撑液膜的气体分离机理,总结目前离子液体支撑液膜的制备方法以及不同膜材料、不同离子液体及其亲疏水性对离子液体支撑液膜稳定性的影响。介绍离子液体支撑液膜在气体分离中的应用,对离子液体支撑液膜的工业化前景进行了展望。     

离子液体支撑液膜的CO2/CH4分离性能

由于离子液体对CO₂具有较好的溶解选择性,离子液体支撑液膜分离CO₂越来越受到关注。比较了含3种不同阴离子的常规离子液体([bmim][BF₄]、[bmim][PF₆]、[bmim][Tf₂N])作为支撑液膜的液膜相分离CO₂/CH₄的性能,考察了咪唑环上烷基链长对离子液体支撑液膜性能的影响。考虑向离子液体中引入胺基和羧基等亲CO₂基团,制备了1-丁基-3-甲基咪唑丙氨酸离子液体([bmim][β-Ala]),考察了 [bmim][β-Ala]支撑液膜分离CO₂/CH₄的性能,并对在CO₂渗透测试前后的支撑液膜进行了FT-IR分析,发现氨基酸离子液体中的-NH₂和CO₂的较强作用以及该离子液体的高黏性影响了CO₂的透过性,使[Bmim][β-Ala]支撑液膜的CO₂透过率低。     

Mass‐transfer rate enhancement for CO2 separation by ionic liquids: Theoretical study on the mechanism

To promote the development of ionic liquid (IL) immobilized sorbents and supported IL membranes (SILMs) for CO₂ separation, the kinetics of CO₂ absorption/desorption in IL immobilized sorbents was studied using a novel method based on nonequilibrium thermodynamics. It shows that the apparent chemical‐potential‐based mass‐transfer coefficients of CO₂ were in three regions with three‐order difference in magnitude for the IL‐film thicknesses in microscale, 100 nm‐scale, and 10 nm‐scale. Using a diffusion‐reaction theory, it is found that by tailoring the IL‐film thickness from microscale to nanoscale, the process was altered from diffusion‐control to reaction‐control, revealing the inherent mechanism for the dramatic rate enhancement. The extension to SILMs shows that the significant improvement of CO₂ flux can be obtained theoretically for the membranes with nanoscale IL‐films, which makes it feasible to implement CO₂ separation by ILs with low investment cost. © 2015 American Institute of Chemical Engineers AIChE J, 61: 4437–4444, 2015     

Development of ethanolamine‐based ionic liquid membranes for efficient CO2/CH4 separation

This study is focused on the development of ionic liquids (ILs) based polymeric membranes for the separation of carbon dioxide (CO₂) from methane (CH₄). The advantage of ILs in selective CO₂ absorption is that it enhances the CO₂ selective separation for the ionic liquid membranes (ILMs). ILMs are developed and characterized with two different ILs using the solution‐casting method. Three different blend compositions of ILs and polysulfone (PSF) are selected for each ILMs 10, 20, and 30 wt %. Effect of the different types of ILs such as triethanolamine formate (TEAF) and triethanolamine acetate (TEAA) are investigated on PSF‐based ILMs. Field emission scanning electron microscopy analysis of the membranes showed reasonable homogeneity between the ILs and PSF. Thermogravimetric analysis showed that by increasing the ILs loading thermal stability of the membranes improved. Mechanical analysis on developed membranes showed that ILs phase reduced the amount of plastic flow of the PSF phase and therefore, fracture takes place at gradually lower strains with increasing ILs content. Gas permeation evaluation was carried out on the developed membranes for CO₂/CH₄ separation between 2 bar to 10 bar feed pressure. Results showed that CO₂ permeance increases with the addition of ILs 10–30 wt % in ILMs. With 20–30 wt % TEAF‐ILMs and TEAA‐ILMs, the highest selectivity of a CO₂/CH₄ 53.96 ± 0.3, 37.64 ± 0.2 and CO₂ permeance 69.5 ± 0.6, 55.21 ± 0.3 is observed for treated membrane at 2–10 bar. The selectivity using mixed gas test at various CO₂/CH₄ compositions shows consistent results with the ideal gas selectivity. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45395.     

Understanding the influence of the ionic liquid composition and the surrounding phase nature on the stability of supported ionic liquid membranes

The industrial application of supported liquid membranes (SLMs) is still limited due to concerns about their stability. In a previous work, the selective separation of the substrates and products of a transesterification reaction was successfully carried out using Nylon membranes impregnated with ionic liquids (ILs). This article analyses the effect of both the IL composition and the nature of the surrounding phase on the stability of these SLMs to design highly stable supported ionic liquid systems. For this purpose, the stability of SLMs based on several ILs after immersion for a week in different feed/receiving phases was characterized using scanning electron microscopy combined with energy dispersive X‐ray (SEM‐EDX). The differential migration of the ILs observed from the membrane toward the surrounding phases was found to be correlated with the solubility of the ILs in the contacting phases. It was observed that SLM stability increased as the polarity of the solvent used as receiving phase decreased and as the hydrophilic character of the ILs used as liquid phase increased. Furthermore, the polymeric support was found to have a strongly stabilizing effect because losses of IL after immersion in a given surrounding phase were much lower than that derived from the solubility of the IL in this phase. © 2011 American Institute of Chemical Engineers AIChE J, 2012     

Polyurethane-based poly (ionic liquid)s for CO2 removal from natural gas

Carbon dioxide separation from CH₄ is important to the environment and natural gas processing. Poly (ionic liquid)s (PILs) based on polyurethane structures are considered as potential materials for CO₂ capture. Thus, a series of anionic PILs based on polyurethane were synthesized. The effects of polyol chemical structure and counter-cations (imidazolium, phosphonium, ammonium, and pyridinium) in CO₂ sorption capacity and CO₂/CH₄ separation performance were evaluated. The synthesized PILs were characterized by NMR, DSC, TGA, dinamical mechanical thermo analysis (DMTA), SEM, and AFM. CO₂ sorption, reusability, and CO₂/CH₄ selectivity were assessed by the pressure-decay technique. The counter-cation and polyol chemical structure play an important role in CO₂ sorption and CO₂/CH₄ selectivity. PILs exhibited competitive thermal mechanical properties. Results showed that PILPC-TBP was the best poly (ionic liquid) for CO₂/CH₄ separation. Moreover, poly (liquid ionic) base polyol (polycarbonate) with phosphonium (PILPC-TBP) demonstrated higher CO₂ sorption capacity (21.4 mgCO₂/g at 303.15 K and 0.08 MPa) as compared to other reported poly (ionic liquids). © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47536.     

State of the art of ionic liquid-modified adsorbents for CO2 capture and separation

The enormous emission of carbon dioxide (CO₂) from industries has triggered a series of environmental issues. In recent years, ionic liquids (ILs) as novel absorbents are widely used for CO₂ capture owing to their low vapor pressure and tunable structures. IL-modified adsorbents have the advantages of both ILs and porous supports, such as high CO₂ selectivity and high specific surface area, which are novel agents to capture CO₂ with broad application prospects. In this review, more than 140 IL-modified adsorbents for CO₂ capture in recent years were systematically summarized. The types of ILs including conventional ILs and functionalized ILs on CO₂ separation performance of different IL hybrid adsorbents, and their adsorption mechanisms were also discussed. Finally, future perspectives on IL-modified adsorbents for CO₂ separation were further posed.     

超临界流体沉积制备[Emim][BF4]支撑型离子液体膜及其气体分离性能

为了进一步提高支撑型离子液体膜的制备效率及其CO2气体分离性能,将离子液体[Emim][BF4]以超临界流体沉积法负载到非对称的Al2O3支撑体内,制备了一系列支撑型离子液体膜,分别测定了CO2和N2两种纯气体在其中的渗透率,探究了制备参数(沉积时间、离子液体加入量和共溶剂加入量)对膜性能的影响规律.结果表明,基于[E...