纤维素醋酸丁酸酯/碳纳米管混合基质膜的气体分离性能

通过溶液复合-溶液成膜的方法,制备了一系列纤维素醋酸丁酸酯(CAB)/多壁碳纳米管(MWCNTs)的新型混合基质膜.表征了CAB/MWCNTs膜材料的形貌、结构与力学性能.结果表明,MWCNTs与CAB界面未见明显缺陷存在,混合基质膜材料具有良好的力学性能.进一步考察了不同MWCNTs含量(2 wt%~30wt%)对CAB/MWCNTs混合基质膜材料的气体分离性能的影响.发现,随着混合基质膜中MWCNTs含量的增加,其对几种测试气体(O2、N2、CH4、CO和CO2)的渗透系数均明显提高,尤其是常见气体对中的"快气"——O2和CO2的渗透系数提高显著:当MWCNTs含量为30 wt%时,所制备的混合基质膜对O2和CO2渗透系数分别达到40.24和180.20 Barrer,比纯CAB膜分别提高了约300%和260%;同时,混合基质膜对多种气体对均表现出优异的分离效果.     

CO_2/CH_4/N_2在MER型沸石中扩散和分离的分子动力学模拟

采用巨正则蒙特卡洛(GCMC)模拟方法研究了CO_2、CH_4和N_2在MER型沸石中的吸附性能,模拟结果与实验结果吻合证明模型和力场是可靠的。在此基础上,以纯硅MER型沸石作为对照,采用分子动力学(MD)模拟方法研究了CO_2、CH_4和N_2在K-MER型沸石中的扩散和分离性能。结果表明,CO_2、CH_4和N_2在MER型沸石中存在亚扩散现象,扩散方式为构型扩散,在沸石三维通道中的扩散存在各向异性。沸石与气体之间的作用力和沸石骨架外阳离子均影响气体分子的扩散能力,而沸石骨架外阳离子是影响气体分子扩散能力的主要因素。CO_2和N_2的自扩散系数随吸附浓度的增加而减小;CH_4的自扩散系数随吸附浓度的增大先增加后减小。CO_2、CH_4和N_2的自扩散系数随温度的升高均增加,扩散活化能大小顺序为N_2 (16.51 kJ/mol) CH_4 (8.39 kJ/mol) CO_2 (4.38 kJ/mol)。K-MER型沸石膜对CO_2/CH_4、CO_2/N_2和N_2/CH_4分离体系均有良好的分离选择性。气体分子的渗透率～104 GPU(1 GPU=3.35×10~(-10) mol/(s·m2·Pa))。     

二氧化钛纳米粒子-氧化石墨烯/聚酰亚胺混合基质膜的原位聚合及气体渗透性能

以钛酸四丁酯为前驱体,采用浸渍-沉淀法制备二氧化钛纳米粒子-氧化石墨烯(TiO_2-GO)复合物,再将TiO_2-GO复合物与4,4'-(六氟异亚丙基)邻苯二甲酸酐和4,4'-二氨基二苯醚通过原位聚合构建TiO_2-GO/TiO_2-GO/PI(聚酰亚胺)混合基质膜,用于CO_2的渗透脱除.采用傅里叶变换红外光谱(FTIR)、拉曼光谱(Raman)、透射电子显微镜(TEM)、扫描电子显微镜(SEM)、热失重(TG)和Zeta电位等表征了TiO_2-GO复合物和TiO_2-GO/PI混合基质膜的形貌与结构;探讨了TiO_2掺杂量对TiO_2-GO复合物及TiO_2-GO/PI混合基质膜的结构和气体渗透性能的影响.结果表明,TiO_2-GO复合物中TiO_2纳米粒子较均匀地沉积在GO片层上,TiO_2纳米粒子在形成的同时破坏了GO的结构,使其无序度增加.TiO_2的掺杂对TiO_2-GO/PI混合基质膜的形貌与结构影响较小,但提升了TiO_2-GO/PI混合基质膜的CO_2和N2渗透性能.但过量的掺杂使TiO_2粒子在GO片层上团聚,从而导致TiO_2-GO复合物在混合基质膜中的分散性变差,CO_2渗透性及CO_2/N2渗透选择性降低.当TiO_2掺杂质量分数为30%时,TiO_2-GO/PI混合基质膜的CO_2渗透性为360 Barrer[1 Barrer=10~(-10)cm~3(STP)·cm/(cm~2·s·cm Hg)=7.5×10~(-14)cm~3(STP)·cm/(cm~2·s·Pa)],CO_2/N_2的渗透选择性可达31.     

用于CO2分离的混合基质膜中填充剂的研究进展

高效、绿色和低能耗的CO_2捕集技术是解决能源气体净化和温室气体减排问题的关键。膜分离技术以其高效、节能、低碳等特点在CO_2捕集领域具有潜在的发展前景。目前,CO_2分离膜的研究主要集中在混合基质膜内的填充剂,通过调控填充剂解决膜内渗透性和选择性间的"博弈"效应。近年来,研究者们发现填充剂通常是影响混合基质膜分离性能的关键因素,采用不同的填充剂可改善混合基质膜的气体分离性能。基于此,本文对目前已经开发出的填充剂进行了归纳总结,以便为设计开发新型混合基质膜用于CO_2分离提供参考。     

多孔材料表面修饰聚酰亚胺非对称混合基质膜对CO2/N2和CO2/CH4的气体分离

兼具高通量和高选择性的气体分离膜是研究膜分离材料的目标.采用相转化法制备了聚酰亚胺非对称膜,并将其作为基底膜材料,分别在其表面修饰掺有金属有机框架材料Cu₃(BTC)₂ (1, 3, 5-均苯三甲酸合铜),沸石咪唑酯骨架材料ZIF-8以及镁铝水滑石MgAl-LDHs的聚酰胺酸溶液,经热亚胺化后制成非对称混合基质膜.研究了该系列非对称混合基质膜的结构特性和对CO₂、CH₄和N₂气体分离性能;考察了ZIF-8的掺杂量对非对称混合基质膜透气性能的影响.结果表明非对称聚酰亚胺膜的表面修饰可有效地改变膜的表面性质,掺杂ZIF-8的非对称混合基质膜气体的透气性能和选择性都增加,且掺杂量为5% (w)时CO₂/N₂和CO₂/CH₄的理想选择性分别高达24和83,为合成高效的CO₂分离膜提供了借鉴.     

金属有机骨架材料/聚酰亚胺混合基质膜的制备及气体分离性能

合成了3种不同结构、 粒径和气体吸附性能的金属有机骨架材料(MOFs): 微米级Cu₃(BTC)₂、 亚微米级ZIF-8和S-Cu₃(BTC)₂. 氮气吸附等温线分析结果表明, ZIF-8和Cu₃(BTC)₂具有较大比表面积(1653和1439 m²/g), S-Cu₃(BTC)₂的比表面积为171.4 m²/g. 用共混法将MOFs直接引入聚酰亚胺中制备了MOFs/聚酰亚胺混合基质膜(MMMs). X射线衍射(XRD)和全反射红外光谱(FTIR-ATR)分析结果表明, MOFs在混合基质膜中保持物理和化学稳定. 气体渗透测试结果表明, MOFs的加入使膜的气体渗透分离性能明显提高, S-Cu₃(BTC)₂使渗透系数增加了1.75倍; ZIF-8和Cu₃(BTC)₂使渗透系数增加了3倍左右; 同时, 膜的气体分离系数变化很小.     

含叔丁基聚酰亚胺均质膜的气体分离性能

采用高温“一步法”缩聚合成了一系列含叔丁基的可溶性芳香聚酰亚胺树脂, 然后通过溶液浇注法制得相应均质薄膜, 并对其气体分离性能进行了测试, 同时研究了二酐结构和温度对聚酰亚胺均质膜气体分离性能的影响. 结果表明, 对于H₂, N₂, O₂, CO₂和CH₄ 等5种气体, 含叔丁基聚酰亚胺均质膜不仅表现出良好的透气性, 而且具有较高的气体透过选择性, 4,4'-(六氟异丙烯)二酞酸酐(6FDA)和均苯四甲酸二酐(PMDA)两类聚酰亚胺均质膜的气体分离性能最佳. 除CO₂外, 这两类聚酰亚胺均质膜的气体渗透系数随温度升高而升高, 而所有测试气体在这两种均质膜中的扩散系数和溶解度系数均随温度升高而增大.     

咔唑基噻咯微孔骨架材料的合成及其气体吸附

分别以1,1-二甲基-3,4-二苯基-2,5-双(4-(9-苯基-咔唑))噻咯、1-甲基-1,3,4-三苯基-2,5-双(4-(9-苯基-咔唑))噻咯和1,1,3,4-四苯基-2,5-双(4-(9-苯基-咔唑)噻咯单元为前驱体,通过氧化偶联聚合,制备了3种微孔骨架材料CPDM-CzS、CPPM-CzS和CPDP-CzS。通过傅里叶红外光谱(FT-IR)、X射线衍射(XRD)、热重分析(TG)、冷场发射扫描电子显微镜(FSEM)和透射电子显微镜(TEM)对3种聚合物的结构和形貌进行了表征,采用N_2吸附、CO_2吸附、H_2吸附和CH_4吸附对材料的孔道性能和气体吸附性能进行了研究。结果表明:CPDM-CzS具有较高的CO_2吸附量(2.1 mmol/g,113 kPa,273 K)和优良的CO_2/N_2选择性气体吸附值(75.2),CPPMCzS具有较高的H_2吸附量(0.0151 g/g,113 kPa,77 K)。     

含有聚醚链段的可溶性聚酰亚胺气体分离膜材料及其性能

将4,4'-六氟亚异丙基-邻苯二甲酸酐(6FDA)和1,3-苯二胺(mPDA)与二端氨基聚醚缩聚, 得到含有聚醚柔性链段的聚酰亚胺气体分离膜材料. 所合成的共聚聚酰亚胺在N-甲基吡咯烷酮(NMP)和四氢呋喃(THF)等有机溶剂中具有良好的溶解性能. 研究了O2, N2, H2, CH4和CO2在聚酰亚胺均质膜中的渗透性能, 考察了二端氨基聚醚的含量、链长和化学结构对气体渗透性能的影响. 结果表明, 聚醚链段的引入增大了气体的扩散系数, 气体的渗透系数显著增大; 聚醚链段与CO2相对较强的相互作用, 增大了对CO2/N2的溶解选择性, CO2/N2的分离性能优于CO2/CH4, 同时CO2比H2优先透过膜.     

不同助剂对CuO-ZnO/SBA-15催化CO_2加氢制甲醇性能影响的研究

以硅质骨架结构介孔分子筛SBA-15为载体,采用浸渍法合成CuO-ZnO/SBA-15(CZ/SBA-15)、CuO-ZnO-MnO_2/SBA-15(CZM/SBA-15)、CuO-ZnO-ZrO_2/SBA-15(CZZ/SBA-15)三组多孔催化剂,在固定床反应器上评价了各组催化剂催化CO_2加氢合成甲醇的性能,同时结合N_2吸附-脱附(BET)、X射线衍射(XRD)、H_2程序升温还原(H_2-TPR)、程序升温脱附(H_2-TPD、CO_2-TPD)、N_2O滴定、X射线光电子能谱(XPS)、透射电子显微镜(TEM)等表征研究了不同助剂对CO_2催化加氢制甲醇的影响。结果表明,催化剂中的金属氧化物改变了SBA-15分子筛载体的孔径大小和比表面积;催化剂CuO-ZnO-MnO_2/SBA-15、CuO-Zn O-ZrO_2/SBA-15中铜的分散度(D_(Cu))和比表面积(A_(Cu))更大,表面CuO粒径更小,更易被还原;相比Mn-O簇,Zr-O簇为增强了碱性位点,提高了甲醇选择性。此外,CuO-ZnO-ZrO_2/SBA-15具有更高的氧空位浓度,催化活性更好,其甲醇选择性为25.02%,与CuO-ZnO/SBA-15、CuO-ZnO-Mn O_2/SBA-15相比分别提高了28%和136.9%,催化效果最好。     

The effects of polymer chain rigidification, zeolite pore size and pore blockage on polyethersulfone (PES)-zeolite A mixed matrix membranes

The polyethersulfone (PES)-zeolite 3A, 4A and 5A mixed matrix membranes (MMMs) were fabricated with a modified solution-casting procedure at high temperatures close to the glass transition temperatures (T_g) of polymer materials. The effects of membrane preparation methodology, zeolite loading and pore size of zeolite on the gas separation performance of these mixed matrix membranes were studied. SEM results show the interface between polymer and zeolite in MMMs experiencing natural cooling is better (i.e., less defective) than that in MMMs experiencing immediate quenching. The increment of glass transition temperature (T_g) of MMMs with zeolite loading confirms the polymer chain rigidification induced by zeolite. The experimental results indicate that a higher zeolite loading results in a decrease in gas permeability and an increase in gas pair selectivity. The unmodified Maxwell model fails to correctly predict the permeability decrease induced by polymer chain rigidification near the zeolite surface and the partial pore blockage of zeolites by the polymer chains. A new modified Maxwell model is therefore proposed. It takes the combined effects of chain rigidification and partial pore blockage of zeolites into calculation. The new model shows much consistent permeability and selectivity predication with experimental data. Surprisingly, an increase in zeolite pore size from 3 to 5 Å generally not only increase gas permeability, but also gas pair selectivity. The O₂/N₂ selectivity of PES-zeolite 3A and PES-zeolite 4A membranes is very similar, while the O₂/N₂ selectivity of PES-zeolite 5A membranes is much higher. This implies the blockage may narrow a part of zeolite 5A pores to approximately 4 Å, which can discriminate the gas pair of O₂ and N₂, and narrow a part of zeolites 3A and 4A pores to smaller sizes. It is concluded that the partial pore blockage of zeolites by the polymer chains has equivalent or more influence on the separation properties of mixed matrix membranes compared with that of the polymer chain rigidification.     

Poly(N,N-dimethylaminoethyl methacrylate)–poly(ethylene oxide) copolymer membranes for selective separation of CO2

A series of copolymers containing ether oxygen groups and amino groups were prepared based on N,N-dimethylaminoethyl methacrylate (DMEMA) and polyethylene glycol methyl ether methyl acrylate (PEGMEMA). The effect of PEGMEMA content in the copolymer on density, free volume, mechanical performance, and H₂, CO₂, N₂ and CH₄ gas transport properties of the copolymer was determined. Free volume was characterized using the polymer density and group contribution theory. The permeability of the copolymer to CO₂ is high, and both the CO₂/N₂ and CO₂/H₂ selectivities are high. For example, the permeability coefficient of PDMAEMA–PEGMEMA-90 (“90” represents the weight percent of PEGMEMA) to CO₂ is 112 Barrer and the CO₂/N₂ and CO₂/H₂ selectivity coefficients are 31 and 7, respectively. The effect of the temperature on gas transport properties was also determined. Finally, the potential application of the copolymer membranes for CO₂/light gases separation was explored.     

Gas transport property of polyallylamine–poly(vinyl alcohol)/polysulfone composite membranes

Polyallylamine (PAAm) was synthesized by free radical polymerization and characterized by Fourier transform infrared resonance (FT-IR) spectroscopy, hydrogen nuclear magnetic resonance (¹H NMR) spectroscopy and differential scanning calorimetry (DSC). The composite membranes were prepared by using PAAm–poly(vinyl alcohol) (PVA) blend polymer as the separation layer and polysulfone (PSF) ultrafiltration membranes as the support layer. The surface and cross-section morphology of the membrane was inspected by environmental scanning electron microscopy (ESEM). The gas transport property of the membranes, including gas permeance, flux and selectivity, were investigated by using pure CO₂, N₂, CH₄ gases and CO₂/N₂ gas mixture (20 vol% CO₂ and 80 vol% N₂) and CO₂/CH₄ gas mixture (10 vol% CO₂ and 90 vol% CH₄). The plots of gas permeance or flux versus feed gas pressure imply that CO₂ permeation through the membranes follows facilitated transport mechanism whereas N₂ and CH₄ permeation follows solution–diffusion mechanism. Effect of PAAm content in the separation layer on gas transport property was investigated by measuring the membranes with 0–50 wt% PAAm content. With increasing PAAm content, gas permeance increases initially, reaches a maximum, and then decreases gradually. For CO₂/N₂ gas mixture, the membranes with 10 wt% PAAm content show the highest CO₂ permeance of about 1.80 × 10⁻⁵ cm³ (STP) cm⁻² s⁻¹ KPa⁻¹ and CO₂/N₂ selectivity of 80 at 0.1 MPa feed gas pressure. For CO₂/CH₄ gas mixture, the membranes with 20 wt% PAAm content display the highest CO₂ permeance of about 1.95 × 10⁻⁵ cm³ (STP) cm⁻² s⁻¹ KPa⁻¹ and CO₂/CH₄ selectivity of 58 at 0.1 MPa feed gas pressure. In order to explore the possible reason of gas permeance varying with PAAm content, the crystallinity of PVA and PAAm–PVA blend polymers was measured by X-ray diffraction (XRD) spectra. The experimental results show an inverse relationship between crystallinity and gas permeance, e.g., a minimum crystallinity and a maximum CO₂ permeance are obtained at 20 wt% PAAm content, indicating that the possibility of increasing CO₂ permeance with PAAm content due to the increase of carrier concentration could be weakened by the increase of crystallinity.     

二维材料膜在气体分离领域的最新研究进展

Two-dimensional (2D) materials, led by graphene, have emerged as nano-building blocks to develop high-performance membranes. The atom-level thickness of nanosheets makes a membrane as thin as possible, thereby minimizing the transport resistance and maximizing the permeation flux. Meanwhile, the sieving channels can be precisely manipulated within sub-nanometer size for molecular separation, such as gas separation. For instance, graphene oxide (GO) channels with an interlayer height of about 0.4 nm assembled by external forces exhibited excellent H₂/CO₂ sieving performance compared to commercial membranes. Cross-linking was also employed to fabricate ultrathin (< 20 nm) GO-facilitated transport membranes for efficient CO₂ capture. A borate-crosslinked membrane exhibited a high CO₂ permeance of 650 GPU (gas permeation unit), and a CO₂/CH₄ selectivity of 75, which is currently the best performance reported for GO-based composite membranes. The CO₂-facilitated transport membrane with piperazine as the carrier also exhibited excellent separation performance under simulated flue gas conditions with CO₂ permeance of 1020 GPU and CO₂/N₂ selectivity as high as 680. In addition, metal-organic frameworks (MOFs) with layered structures, if successfully exfoliated, can serve as diverse sources for MOF nanosheets that can be fabricated into high-performance membranes. It is challenging to maintain the structural and morphological integrity of nanosheets. Poly[Zn₂(benzimidazole)₄] (Zn₂(bim)₄) was firstly exfoliated into 1-nm-thick nanosheets and assembled into ultrathin membranes possessing both high permeance and excellent molecular sieving properties for H₂/CO₂ separation. Interestingly, reversed thermo-switchable molecular sieving was also demonstrated in membranes composed of 2D MOF nanosheets. Besides, researchers employed layered double hydroxides (LDHs) to prepare molecular-sieving membranes via in situ growth, and the as-prepared membranes showed a remarkable selectivity of ~80 for H₂-CH₄ mixture. They concluded that the amount of CO₂ in the precursor solution contributed to LDH membranes with various preferred orientations and thicknesses. Apart from these 2D materials, MXenes also show great potential in selective gas permeation. Lamellar stacked MXene membranes with aligned and regular sub-nanometer channels exhibited excellent gas separation performance. Moreover, our ultrathin (20 nm) MXene nanofilms showed outstanding molecular sieving property for the preferential transport of H₂, with H₂ permeance as high as 1584 GPU and H₂/CO₂ selectivity of 27. The originally H₂-selective MXene membranes could be transformed into membranes selectively permeating CO₂ by chemical tuning of the MXene nanochannels. This paper briefly reviews the latest groundbreaking studies in 2D-material membranes for gas separation, with a focus on sub-nanometer 2D channels, exfoliation of 2D nanosheets with structural integrity, and tunable gas transport property. Challenges, in terms of the mass production of 2D nanosheets, scale-up of lab-level membranes and a thorough understanding of the transport mechanism, and the potential of 2D-material membranes for wide implementation are briefly discussed.     

Gas permeability in rubbery polyphosphazene membranes

The synthesis, characterization, and gas permeability of 10 new polyphosphazenes has been studied. Additionally, the first gas permeation data has been collected on hydrolytically unstable poly[bis-(chloro)phosphazene]. Gases used in this study include CO₂, CH₄, O₂, N₂, H₂, and Ar. CO₂ was the most permeable gas through any of the phosphazenes and a direct correlation between the T_g of the polymer and CO₂ transport was noted with permeability increasing with decreasing polymer T_g. To a lesser degree, permeability of all the other gases studied also yielded increases with decreasing polymer T_g. The trend observed for these new polymers was further supported by published data for other phosphazenes. Furthermore, permeability data for all gases were found to correlate to the gas condensability and the gas critical pressures, except for hydrogen, suggesting that the nature of the gas is also a significant factor for permeation through rubbery phosphazene membranes. Ideal separation factors () for the CO₂/H₂ and CO₂/CH₄ gas pairs were calculated. For CO₂/CH₄, no increase in was observed with decreasing T_g, however increases in were noted for the CO₂/H₂ pair.     

Systematic investigation of the effects of temperature and pressure on gas transport through polyurethane/poly(methylmethacrylate) phase-separated blends

Polyurethane (PU) and polyurethane–poly(methylmethacrylate) (PMMA) blend membranes were used in gas separation studies. The effects of blend composition, temperature, and pressure on the permeability, diffusivity, and solubility of CO₂, H₂, O₂, CH₄, and N₂ were investigated. The separation factors of some gas pairs were also evaluated. Positron annihilation lifetime spectroscopy was applied to assess free volume changes as a function of blend composition and temperature. Free volume size increases by approximately 30% with increasing temperature from 10 to 40 °C for all blends studied. The permeability of all gases decreases by approximately 55% with the addition of 30 wt% of PMMA. The permeation process is governed by diffusion, except that of CO₂. In relation to the behavior of gas transport as a function of temperature, some important observations are (i) CO₂ presents the lowest permeation activation energy value (28 kJ/mol), and (ii) gas pair selectivity increases at low temperatures and is high for gas pairs that present differences in permeation activation energies as high as 15 kJ/mol for the CO₂/CH₄ gas pair. Furthermore, the study with pressure variations shows that: (i) at elevated pressure, the PU and the blend membrane permeability to CO₂ and H₂ increases by approximately 35%, and (ii) oxygen-to-nitrogen selectivity increases with pressure as a consequence of the decrease in the permeability to nitrogen in the case of the 30%-PMMA blend.     

聚合物支撑的金属有机骨架膜的制备及其气体分离性能

由于MOF(金属有机骨架)膜与基底之间的作用力较薄弱,所以制备具有高的H_2渗透性和H_2/CO_2选择性的致密连续的大面积金属有机骨架膜仍具有巨大挑战。本文选取多孔Al_2O_3作为基底,在表面涂覆一层PIM-1(一种固有微孔聚合物),并对其进行羧基化处理,使得表面具有大量的羧基基团,随后利用羧基与金属之间的相互作用,原位生长得到了两种致密连续的聚合物支撑的MOF膜(PIM-1-COOH/ZIF-8和PIM-1-COOH/HKUST-1)。通过XRD的表征可以看出MOF膜是纯相的并且具有较高的结晶性;SEM的测试结果表明MOF膜是致密连续的并且MOF膜与基底之间紧密结合。气体分离测试结果表明,这两种MOF膜对H_2具有较高的渗透性以及H_2/CO_2选择性。在常温常压下,对于PIM-1-COOH/ZIF-8和PIM-1-COOH/HKUST-1膜,H_2/CO_2双组分气体的分离系数分别为7.32、9.69,并且它们H_2的渗透通量分别高于3.16×10~(-6)、1.14×10~(-6) mol·m~(-2)·s~(-1)·Pa~(-1)。在单组份测试中,这两种MOF膜的H_2/CO_2的理想分离系数分别为7.70、12.04;H_2的渗透通量分别高达3.73×10~(-6)、3.86×10~(-6) mol·m~(-2)·s~(-1)·Pa~(-1),这就表明这两种MOF膜有望在H_2的纯化和分离方面广泛应用。     

Gas permeation through water-swollen hydrogel membranes

This work deals with water-swollen hydrogel membranes for potential CO₂ separation applications, with an emphasis on elucidating the role of water in the membrane for gas permeation. A series of hydrogel membranes with a wide range of water contents (0.9–10 g water/g polymer) were prepared from poly(vinyl alcohol), chitosan, carboxyl methyl cellulose, alginic acid and poly(vinylamine), and the permeation of CO₂, H₂, He and N₂ through the membranes at different pressures (200–800 kPa) was studied. The gas permeabilities through the dry dense membranes were measured as well to evaluate the resistance of the polymer matrix in the hydrogel membranes. It was shown that the gas permeability in water-swollen membrane is lower than the gas permeability in water, and the selectivity of the water-swollen membranes to a pair of gases is close to the ratios of their permeabilities in water. The permeability of the water-swollen membranes increases with an increase in the swelling degree of the membrane, and the membrane permeability tends to level off when the water content is sufficiently high. A resistance model was proposed to describe gas permeation through the hydrogel membranes, where the immobilized water retained in the polymer matrix was considered to form transport passageways for gas permeation through the membrane. It was shown that the permeability of hydrogel membranes was primarily determined by the water content in the membrane. The model predictions were consistent with the experimental data for various hydrogel membranes with a wide range of water contents (0.4–10 g water/g polymer).