Gas Separation Applications Research Articles

Tailor-Made Modification of Commercial Ceramic Membranes for Environmental and Energy-Oriented Gas Separation Applications.

Ceramic membranes have been considered as potential candidates for several gas separation processes of industrial interest, due to their increased thermal and chemical stability compared to polymeric ones. In the present study, commercial Hybrid Silica (HybSi®) membranes have been evaluated and modified accordingly, to enhance their gas separation performance for targeted applications, including CO2 removal from flue gas and H2 recovery from hydrogen-containing natural gas streams. The developed membranes have been characterized before and after modification by relative permeability, single gas permeation, and equimolar separation tests of the respective gas mixtures. The modification procedures, involving in situ chemical vapor deposition and superficial functionalization, aim for precise control of the membranes’ pore size and surface chemistry. High performance membranes have been successfully developed, presenting an increase in H2/CH4 permselectivity from 12.8 to 45.6 at 250 °C. Ultimately, the modified HybSi® membrane exhibits a promising separation performance at 250 °C, and 5 bar feed pressure, obtaining above 92% H2 purity in the product stream combined with a notable H2 recovery of 65%, which can be further improved if a vacuum is applied on the permeate side, leading to 94.3% H2 purity and 69% H2 recovery.

Copper nanoparticles decorated N-doped mesoporous carbon with bimodal pores for selective gas separation and energy storage applications

• Mesoporous N & Cu doped carbon materials with enhanced physico-chemical features. • Materials display redox, conducting, basic, adsorption and porous characteristics. • N/Cu doped carons show ordered structure with a bimodal pores size distribution. • High gas adsorption capacity and selectivity in a mixture of CO 2 /H 2 and CO 2 /CH 4. • High values for supercapacitance with good cyclic ability and capacitance retention. We demonstrate a synthesis of copper nanoparticles decorated over nitrogen-doped mesoporous carbon with different N and Cu contents which exhibit conducting, redox, basic, adsorption, and excellent textural properties. These materials are prepared through a nanotemplating approach by simultaneously encapsulating sucrose, guanidine hydrochloride, and Cu(NO 3 ) 2 into the porous channels of mesoporous SBA-15 at a low carbonization temperature of 600 °C. The prepared materials exhibit an ordered mesoporous carbon framework with bimodal pores, decorated with nitrogen and Cu functionalities on the surface of the pores and in the wall structure. The presence of nitrogen functionalities in the porous carbon matrix not only helps to reduce the Cu ions but also stabilizes the nanoparticles and offers redox sites, which are beneficial for adsorption and electrochemical applications. The optimized sample exhibits the highest adsorption capacity of different gases such as CO 2 – 22.5 mmol/g at 273 K, H 2 −13.5 mmol/g at 77 K at 30 bar and CH 4 − 5 mmol/g at 298 K and 50 bar. We also demonstrate that the prepared material shows a high selectivity of adsorption towards CO 2 in a mixture of CO 2 /H 2 and CO 2 /CH 4 and it also registers a high supercapacitance of 209 F g −1 at a current density of 1 A g −1 with excellent cyclic stability.

Mixed‐matrix gas separation membranes for sustainable future: A mini review

AbstractMixed‐matrix membranes (MMMs), merging the advantages of polymers and inorganic fillers, has become a preferable choice as future gas separation membrane. Owing to hierarchical structures, MMMs are suitable for high‐performance gas separation capability. Research on extended porous organic/inorganic materials also known as fillers of intrinsic nanopores (FINS) such as porous organic frameworks (POFs), Zeolites, metal–organic frameworks (MOFs), porous organic cages (POCs) and analogous metal–organic polyhedral (MOPs) have bloomed over the last two decades. MOFs and POFs have been proposed as good adsorbent and promising filler components for industrial gas separations, due to their prominent porosity and structural flexibility and also for MMMs with good performance in terms of permeance and selectivity. They are compatible for providing additional molecular transport channels as well as having good size‐sieving property. This review briefly outlines the innovative trends in MMMs, highlighted with different porous fillers as well as suitable polymers followed by their synthesis and their suitable application in gas separations. Finally, a state of art and challenges in the direction of actual application of MMMs in different industries are outlined in terms of inter relation and regarding the future direction and potential growth opportunities of MMMs an elaborate discussion is provided.

Surface Modification of Matrimid® 5218 Polyimide Membrane with Fluorine-Containing Diamines for Efficient Gas Separation.

Polyimide membranes have been widely investigated in gas separation applications due to their high separation abilities, excellent processability, relatively low cost, and stabilities. Unfortunately, it is extremely challenging to simultaneously achieve both improved gas permeability and selectivity due to the trade-off relationship in common polymer membranes. Diamine modification is a simple strategy to tune the separation performance of polyimide membranes, but an excessive loss in permeability is also generally observed. In the present work, we reported the effects of diamine type (i.e., non-fluorinated and fluorinated) on the physicochemical properties and the corresponding separation performance of a modified membrane using a commercial Matrimid® 5218 polyimide. Detailed spectroscopic, thermal, and surface analyses reveal that the bulky fluorine groups are responsible for the balanced chain packing modes in the resulting Matrimid membranes compared to the non-fluorinated diamines. Consequently, the modified Matrimid membranes using fluorinated diamines exhibit both higher gas permeability and selectivity than those of pristine Matrimid, making them especially effective for improving the separation performance towards H2/CH4 and CO2/CH4 pairs. The results indicate that the use of fluorinated modifiers may offer new opportunities to tune the gas transport properties of polyimide membranes.

Improving Ethane/Ethylene Separation Performance under Humid Conditions by Spatially Modified Zeolitic Imidazolate Frameworks.

Gas separation performances are usually degraded under humid conditions for many crystalline porous materials because of the lack of water stability and/or the competition of water vapor toward the interaction sites (e.g., open metal sites). Zeolitic imidazolate frameworks (ZIFs) are suitable candidates for practical applications in gas separation because of their excellent physical/chemical stabilities. However, the limitation of substituent positions in common ZIFs has prevented extensive pore engineering to improve their separation performance. In a type of gyroidal ZIFs with gie topology, the Schiff base moiety provides additional substituent positions, making it possible to modify the spatial arrangement of hydrophobic methyl groups. Herein, a new gyroidal ZIF, ZnBAIm (H2BAIm = 1,2-bis(1-(1H-imidazol-4-yl)ethylidene)hydrazine), is designed, synthesized, and characterized. The spatially modified ZnBAIm exhibits improved thermal/chemical/mechanical stabilities compared to ZnBIm (H2BIm = 1,2-bis((5H-imidazol-4-yl)methylene)hydrazine). ZnBAIm can remain intact up to about 480 °C in a N2 atmosphere and tolerate harsh treatments (e.g., 5 M NaOH aqueous solution at room temperature for 24 h and 190 MPa high pressure in the presence of water). Moreover, the modified pore and window sizes have improved significantly the ethane/ethylene selectivity and separation performance under humid conditions for ZnBAIm. Breakthrough experiments demonstrate efficient separation of a C2H6/C2H4 (50/50, v/v) binary gas mixture under ambient conditions; more importantly, the C2H6/C2H4 separation performance is unaffected under highly humid conditions (up to 80% RH). The separation performance is attributed to combined thermodynamic (stronger dispersion interaction with C2H6 than with C2H4) and kinetic factors (diffusion), determined by density functional theory calculations and kinetic adsorption study, respectively.

Polybenzimidazole-derived carbon molecular sieve hollow fiber membranes with tailored oxygen selective transport

Polymer membrane carbonization is a promising strategy to obtain carbon molecular sieve (CMS) membrane materials with tailorable cavity size distributions for high gas selectivities beyond that attained from traditional polymer membrane materials. Despite their already demonstrated exceptional separation performance characteristics for several gas separation applications (e.g. CO2/CH4 and H2/CO2), further development of CMS membranes having high O2/N2 perm-selectivity for energy-efficient high-purity O2 production has proven challenging. Herein, we explore CMS hollow fiber membranes (HFMs) derived from highly rigid and tightly-packed polybenzimidazole (PBI) materials. Nearly defect-free PBI-derived CMS HFMs were fabricated and evaluated for O2/N2 separation performance for the first time. The micro-structural and O2 selective gas separation characteristics of PBI-CMS HFMs pyrolyzed at different pyrolysis conditions were intensively studied. With rigorous carbonization protocol optimization, we obtained highly O2 permselective PBI-CMS HFMs having O2/N2 selectivities approaching 14, enabling high purity O2 production. The PBI-CMS HFM O2/N2 separation performance dependence on operating conditions (e.g. temperature and feed pressure) are reported.

Data-Driven Matching of Experimental Crystal Structures and Gas Adsorption Isotherms of Metal–Organic Frameworks

Porous metal–organic frameworks are a class of materials with great promise in gas separation and gas storage applications. Due to the high dimensional space of materials science and engineering, computational screening techniques have long been an important part of the scientific toolbox. However, a broad validation of molecular simulations in these materials is impeded by the lack of a connection between databases of gas adsorption experiments and databases of the atomic crystal structure of corresponding materials. This work aims to connect the gas adsorption isotherms of metal–organic frameworks collected in the NIST/ARPA-E Database of Novel and Emerging Adsorbent Materials to the corresponding crystal structures in the Cambridge Structural Database. With tens of thousands of isotherms and crystal structures reported to date, an automatic approach is needed to establish this link, which we describe in this paper. As a first application and consistency check, we compare the pore volume measured from low-temperature argon or nitrogen isotherms to the geometrical pore volume computed from the crystal structure. Overall, 545 argon or nitrogen isotherms could be matched to a corresponding crystal structure. We find that the pore volume computed via the two complementary methods shows acceptable agreement only in about 35% of these cases. We provide the subset of isotherms measured on these materials as a seed for a future and more complete reference data set for computational studies.

Small-Pore Zeolite Membranes: A Review of Gas Separation Applications and Membrane Preparation

There have been significant advancements in small-pore zeolite membranes in recent years. With pore size closely related to many energy- or environment-related gas molecules, small-pore zeolite membranes have demonstrated great potential for the separation of some interested gas pairs, such as CO2/CH4, CO2/N2 and N2/CH4. Small-pore zeolite membranes share some characteristics but also have distinctive differences depending on their framework, structure and zeolite chemistry. Through this mini review, the separation performance of different types of zeolite membranes with respect to interested gas pairs will be compared. We aim to give readers an idea of membrane separation status. A few representative synthesis conditions are arbitrarily chosen and summarized, along with the corresponding separation performance. This review can be used as a quick reference with respect to the influence of synthesis conditions on membrane quality. At the end, some general findings and perspectives will be discussed.

Shaping of metal–organic frameworks through a calcium alginate method towards ethylene/ethane separation

The separation of ethylene and ethane is a crucial, challenging and cost-intensive process in chemical engineering. Metal–organic frameworks (MOFs) are a class of novel porous adsorbents used for the separation of ethylene/ethane mixtures. However, MOFs are normally crystalline powders that cause multiple problems, such as dust, abrasion and heat/mass loss, as well as significant pressure drops on the adsorption bed resulting in a sudden stop in production. To solve these issues, we have prepared four different sphere-shaped adsorbents, including Mg-gallate, Co-gallate, MUV-10(Mn) and MIL-53(Al) using a calcium alginate method to achieve excellent ethylene/ethane separation performance. The performance of the sphere-shaped adsorbents has been validated using mechanical strength measurements, powder X-ray diffraction, scanning electron microscopy, thermogravimetric analysis, gas adsorption isotherms and dynamic breakthrough experiments. The excellent mechanical strength of these sphere-shaped adsorbents meets the criteria for industrial application in gas separation. Thus, the energy consumption and operating cost will be further reduced in the ethylene production process. We believe that this shaping method will open a prosperous route to the development of MOFs toward higher technology levels and their commercial application.

Synergistic effect of hybridized TNT@GO fillers in CTA-based mixed matrix membranes for selective CO2/CH4 separation

Titanium dioxide nanotube (TNT) amalgamated graphene oxide (GO) matrix was blended with cellulose triacetate (CTA) polymer to form a new kind of mixed matrix membranes (MMMs) for the selective biogas upgrading. The effect of hybrid fillers on the physico-chemical, thermal and mechanical properties of membranes were studied using different spectroscopic techniques. Notable improvements on these properties were observed on MMMs as compared to the pristine membrane. Similarly, resulting MMMs exhibited higher CO2 adsorption affinity. Furthermore, single gas permeation measurements revealed higher permeability as well as selectivity for [email protected]/CTA membrane. CO2 permeability increased almost 7 times, reaching 22.54 Barrer, whereas CO2/CH4 selectivity increased nearly three folds from 25.06 for the pristine membrane to 86.69 for [email protected]/CTA membrane and reached the Robeson 2008 upper bound. The long term stability experiment of the [email protected]/CTA membrane confirm the anti-aging ability suggesting its practical application in the bio/natural gas upgrading process. These results established an effective modification approach for applying alternative porous hybrid fillers into gas separation applications.

Application of imine covalent organic frameworks in sample pretreatment

亚胺类共价有机骨架(I-COFs)是有机单体根据席夫碱(Schiff-base)反应原理缩合形成的一类新型多孔晶体有机材料。I-COFs具有骨架密度低、比表面积大、孔隙率高、单体种类丰富、孔径尺寸可控、结构可功能化、合成方法多样和物化稳定性好等优点。近年来,I-COFs已成为材料科学领域的研究前沿,并广泛用于气体吸附、存储、催化、传感、光电材料等方面。I-COFs材料优异的物理化学性能使其非常适于用作复杂样品中痕量目标物的分离富集介质,其高比表面积、高孔隙率性能赋予了它极高的吸附负载量,这些性能使得目标分析物可被高效富集;通过控制有机单体的链段长度、几何结构、掺杂元素、取代基团等方面精确调控I-COFs的孔洞结构和功能化基团,从而实现目标痕量物质的选择性富集。目前,I-COFs材料在样品前处理领域作为新型萃取介质已引起了极大关注。该文综述了近年来I-COFs材料的主要类型、合成方法及其在固相萃取、磁性固相萃取、分散固相萃取和固相微萃取方面的研究进展,同时展望了I-COFs在样品前处理领域的发展前景。

Recent advances and challenges of metal–organic framework/graphene-based composites

Metal–organic frameworks (MOFs) are a new kind of porous crystalline material synthesized by the assembly of metal ions and organic ligands, which have the advantages of a large specific surface area, high porosity, and tunable pore structures and morphological features. Owing to their ease of design as well as uniform and fine-tunable pore structures, MOFs are widely employed in several applications, such as in catalysts, supercapacitors , adsorbents, sensors, environmental protection, and drug delivery. However, the poor stability and electrical conductivity of traditional MOFs limit their applications. Using graphene-based materials with rich functional groups as templates for the growth of MOF particles can not only alleviate the poor conductivity and structural instability of MOFs, but also avoid the aggregation and restacking phenomenon between graphene sheets , thereby greatly expanding the application scope of MOFs. Due to the tunable structure and composition of derivatives, MOF-derived/graphene materials can also be used as multifunctional precursors, especially in the field of electrochemistry. The latest synthesis methods of MOF/graphene composites and their derivatives, as well as their diverse applications, are reviewed in this paper. In addition, the future development opportunities and challenges corresponding to MOF/graphene composites are discussed. The preparation of MOF/graphene-based composites and their applications in batteries, supercapacitors, electrocatalysts, water purification, gas separation and storage, chemical sensors and other fields. • Improving the electrical conductivity of MOFs. • To solve the aggregation and restacking phenomena of graphene. • Synergistic effect of MOFs and graphene. • Various morphologies of MOF/graphene composites. • Analyzing the advantages of MOF/graphene composites for various applications.

High performance of PES-GNs MMMs for gas separation and selectivity

In this study, graphene nanosheets (GNs) were incorporated into polyethersulfone (PES) by phase inversion approach for preparing PES-GNs mixed matrix membranes (MMMs). To investigate the impact of filler content on membrane surface morphology, thermal stability, chemical composition, porosity and mechanical properties, MMMs were constructed with various GNs loadings (0.01, 0.02, 0.03, and 0.04 wt%). ​The performance of prepared MMMs was tested for separation and selectivity of CO2, N2, H2 and CH4 gases at various pressures from 1 to 6 bar and temperature varying from 20 to 60 °C. It was observed that, compared to the pristine PES membrane, the prepared MMMs significantly improved the gas separation and selectivity performance with adequate mechanical stability. The permeability of CO2, N2, H2 and CH4 for the PES + 0.04 wt% GNs increases from 9 to 2246, 11 to 2235, 9 to 7151, and 3 to 4176 Barrer respectively, as compared with pure PES membrane at 1 bar and 20 °C due to improving the membrane absorption and porosity. In addition, by increasing the pressure, the permeability and selectivity of CO2, N2, H2 and CH4 are increased due to the increased driving force for the transport of gas via membranes. Furthermore, the permeability of CO2, N2, H2 and CH4 increased by increasing the temperature from 20 to 60 °C due to the plasticization in the membranes and the improvement in polymer chain movement. This result proved that the prepared membranes can be used for gas separation applications.

Gas sorption and diffusion in perfluoro(butenyl vinyl ether) based perfluoropolymeric membranes

Amorphous glassy perfluoropolymers are characterized by high fractional free volume and hydrocarbon phobicity which means that they perform at the upper bound for several gas pairs. In this study, the sorption of a range of pure gases in Cytop® and a CyclAFlorTM random copolymer of perfluoro(butenyl vinyl ether) (PBVE) and perfluoro(2,2-dimethyl-1,3-dioxole) (PDD) are studied for the first time at different temperatures. The Non-Equilibrium Lattice Fluid (NELF) model is used to model the sorption isotherms in Cytop®, after the determination of the Sanchez-Lacombe model parameters from literature data of the polymer volumetric behavior. The Dual Mode Sorption model is used to model the sorption isotherms in Poly(50%PBVE-co-50%PDD). These results and previously published permeability data are then used within a transport model to determine the diffusivity and activation energy of diffusion for a range of gases within these polymers. The CyclAFlor™ copolymer is shown to have a higher CO2 diffusivity than Cytop®, while maintaining comparable CO2/CH4 diffusivity selectivity. Molecular Dynamics (MD) simulations are performed as a comparison, to calculate the Fickian diffusion coefficients at 35 °C. The diffusion coefficients obtained from MD are consistent with those calculated by the transport model for He and H2 but deviate for larger penetrants (i.e. CO2 and CH4). The results confirm the superior performance of the CyclAFlor™ copolymer for gas separation applications, with greater CO2 solubility and diffusivity than comparable polymers.

Inverse Gas Chromatography as a Screening Technique for Henry’s Law Constants of Gases in Ionic Liquids

Henry’s law constants of various gases in 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([bmim][Tf2N]), 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([emim][Tf2N]), 1-allyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([allylmim][Tf2N]), and 1-ethyl-3-methylimidazolium ethylsulfate ([emim][EtSO4]) were measured using an inverse gas chromatography (GC) method. The gases explored were carbon dioxide, ethane, ethylene, propane, and propylene at temperatures ranging from 298.15 to 373.15 K. The temperature dependence of the Henry’s law constants was used to determine the standard enthalpies of absorption of the gases in the ionic liquids (ILs). Comparison of our measured values of Henry’s law constants and enthalpies with the literature leads to the conclusion that the GC method is a fast technique for screening ILs for various gas separation applications.

Graphene nanoplatelets based polyimide/Pebax dual-layer mixed matrix hollow fiber membranes for CO2/CH4 and He/N2 separations

Mixed matrix membranes are key in the preparation of stable, stretchy, durable and efficient membranes for gas separation applications. To this aim, the perfect filler nanomaterials’ dispersion is needed. At the same time the replacement of toxic solvents with green ones is also a priority in science, including the membrane technology. Herein, we present the development steps, their structural characteristics and the gas selectivity properties of graphene nanoplatelets (GNPs) based mixed matrix hollow fiber (HF) membranes. In specific, dual-layer composite polymeric hollow fiber membranes, for CO2/CH4 and He/N2 gas separations, were prepared by directly dip-coating a single selective layer on prepared porous HF supports without the use of any gutter layer. Asymmetric BTDA-TDI/MDI (P84) co-polyimide-based HFs that acted as porous supports, were fabricated via the dry-wet phase inversion process and the commercial poly(ether-block-amide) Pebax-1657 was chosen as a high CO2-selective separation layer material, dip-coated on the HF supports. The positive influence of the incorporation of GNPs as promising nanofiller in both, the polymeric matrix (support) and the selective layer, in parallel with the partial replacement of toxic NMP by GBL -a "green" solvent- in the support's spinning process, were all evaluated and confirmed. CO2/CH4 and He/N2 selectivities up to 82 and 20, respectively with CO2 and He permeances of 3 and 2.7 GPU, respectively were measured under real binary gas mixture conditions at 1.3 bar(a) transmembrane pressure at 298 K for dual-layer composite, with GNPs filler, HF (DL-HF) membranes.

Ti-40Al-10Nb-10Cr Porous Microfiltration Membrane with Hierarchical Pore Structure for Particulate Matter Capturing from High-Temperature Flue Gas.

TiAl-based porous microfiltration membranes are expected to be the next-generation filtration materials for potential applications in high-temperature flue gas separation in corrosive environments. Unfortunately, the insufficient high-temperature oxidation resistance severely limits their industrial applications. To tackle this issue, a Ti-40Al-10Nb-10Cr porous alloy was fabricated for highly effective high-temperature flue gas purification. Benefited from microstructural changes and the formation of two new phases, the Ti-40Al-10Nb-10Cr porous alloy demonstrated favorable high-temperature anti-oxidation performance with the incorporation of Nb and Cr high-temperature alloying elements. By the separation of a simulated high-temperature flue gas, we achieved an ultra-high PM-removal efficiency (62.242% for PM<2.5 and 98.563% for PM>2.5). These features, combined with our experimental design strategy, provide a new insight into designing high-temperature TiAl-based porous materials with enhanced performance and durability.

Ultra-highly porous carbon from Wasted soybean residue with tailored porosity and doped structure as renewable multi-purpose absorbent for efficient CO2, toluene and water vapor capture

Renewable and cost-efficient absorbent is of continuous interest to address the challenges induced by greenhouse gas and volatile organic chemicals (VOCs). Inspired by the needs for pyrolysis valorization of organic solid wastes, this work reported the synthesis of series of super-developed porous carbons with specific surface area and total pore volume up to 4293 m2/g and 2.52 cm3/g, respectively, via easily scalable KOH activation of pyrolysis char from waste soybean residue. By finely regulating the synthesis parameters, the resultants offered tunable porosity and surface chemistry for exceptionally high CO2/N2 selectivity (308 by Henry's Law at 298 K) and ultrahigh absorption capacity toward toluene (1587 mg/g under P/P0 of 0.99 and 25 °C) and water vapor (2187 mg/g under P/P0 of 0.9–1 and 25 °C). These features made them competitive candidates as physical absorbents for CO2 capture, VOCs removal and dehumidification. Furthermore, the CO2 molecules generally experienced adsorption at ultramicropores and doped sites, in addition to stacking in larger pore space under higher pressure. By contrast, the hierarchical porosity offered extensive surface and space for vapor adsorption, whilst those aromatic and oxygenic structures at surface may further interact with non-polar toluene and polar H2O, respectively. The current products can be envisioned with a broader application in gas separation given the findings here. Besides, conversion of solid char instead of directly the raw biomass waste is worthy of both academic and industrial focuses toward optimal valorization of biomass waste.

Shaping techniques of adsorbents and their applications in gas separation: a review

This paper reviews recent advances in the shaping adsorbents: alternative geometric forms, key metrics for evaluation, typical steps of main shaping techniques,etc., are discussed, which can serve as a reference for structured adsorbent design.

Highly steam-stable CHA-type zeolite imidazole framework ZIF-302 membrane for hydrogen separation

Metal-organic frameworks (MOFs) as molecular sieve membrane materials have received extensive attention on the gas separation application. However, the membrane separation performance is extremely limited by its intrinsic stability of frameworks. The successful preparation of high-quality gas separation membranes with excellent stability remains a grand challenge. ZIF-302 is based on hydrophobic ligand in-situ design with a high-stabile chabazite (CHA) topology. Herein, we synthesized uniform ZIF-302 nanocrystals with exceptional stability by introducing a modulator. Correspondingly, the continuous dense ZIF-302 polycrystalline membranes were also prepared for the separation of H2, N2, CO2, CH4 and other gases. The permeance of H2 and separation factor for H2/CH4 mixtures at 35 °C and 1 bar were 2.8 × 10-8 mol m−2 s−1 Pa−1 and 51.5, respectively, exceeding the Robeson upper bound in 2008. Furthermore, the separation performance of the super-hydrophobic ZIF-302 membranes for humidified mixed gases can maintain more than 168 h at 35 °C, indicating reliable long-term operational stability. Therefore, the CHA-type ZIF-302 polycrystalline membrane is promising for actual industrial gas separation.