Single Gas Permeation Research Articles

Separation of Light Gases from Xenon over Porous Organic Cage Membranes.

Herein, we demonstrate the successful synthesis and separation ability of CC3 porous organic cage membranes grown on tubular supports for light gases He, CO2, CH4, and Kr over xenon. CC3 membranes were synthesized using secondary seeded growth and displayed different separation performances depending on the crystal size, size distribution of the seeds, and membrane thickness. CC3 membranes as thin as ∼2.5 μm resulted in high single gas permeances of 2114, 1962, 1705, 773, and 162 GPU, for He, CH4, CO2, Kr, and Xe, respectively. The highest ideal selectivities for He/Xe, CH4/Xe, CO2/Xe, and Kr/Xe gas pairs were 13, 12, 10.5, and 4.8, respectively. Mechanistically, the membranes separated He, CO2, Kr, and CH4 from Xe mainly via gas diffusivity differences. Therefore, the separation was kinetically driven.

Preparation of Pt-ZSM-5 zeolite membrane catalysts for the isomerization of linear alkane

A ZSM-5 supported membrane was synthesized by secondary growth method. The Pt-ZSM5 membrane was prepared by impregnation method. The membrane was characterized by single gas permeation step at room temperature. The isomerization of n-pentane was chosen as a probe reaction for evaluating the catalytic performance of the membrane. In particular, the effect of the space velocity and the time on stream were considered. After the catalytic tests, the membrane was characterized by SEM, EDX and XRD. N2 permeance for the membrane, after calcination, was equal to 2.9 × 10-7 mol/m2.s.Pa indicating a coverage of the larger support pores by the zeolite crystals. This results was also confirmed by the SEM investigation. In addition, XRD analysis showed as the ZSM-5 was the desired zeolite-type. During the catalytic tests, it was observed a decrease of the nC5 conversion and an increase of the iC5 selectivity with WHSV. The nC5 conversion was decreased from 2.5 to less than 0.5, with an enhancement in weight hourly space velocity (WHSV), while the selectivity increases from 30 to over 70. On the other hand, it's conversion on catalyst enhanced from 10% to approximately 38%, with an increase in the reaction temperature from 250 to 450°C.

Unprecedentedly Low CO2 Transport through Vertically Aligned, Conical Silicon Nanotube Membranes.

Nanotube membranes could show significantly enhanced permeance and selectivity for gas separations. Up until now, studies have primarily focused on applying carbon nanotubes to membranes to achieve ultrafast mass transport. Here, we report the first preparation of silicon nanotube (SiNT) membranes via a template-assisted method and investigate the gas transport behavior through these SiNT membranes using single- and mixed-gas permeation experiments. The SiNT membranes consist of conical cylinder-shaped nanotubes vertically aligned on a porous silicon wafer substrate. The diameter of the SiNT pore mouths are 10 and 30 nm, and the average inner diameter of the tube body is 80 nm. Interestingly, among the gases tested, we found an unprecedentedly low CO2 permeance through the SiNT membranes in single-gas permeation experiments, exceeding the theoretical Knudsen selectivity toward small gases/CO2 separation. This behavior was caused by the reduction of CO2 permeability through the blocking effect of CO2 adsorbed in the narrow pore channels of the SiNT cone regions, indicating that CO2 molecules have a high affinity to the native silicon oxide layer (∼2 nm) that is formed on the inner walls of SiNTs. SiNT membranes also exhibited enhanced gas permeance and water flux as compared to classic theoretical models and, as such, may prove useful as a new type of nanotube material for use in membrane applications.

Separation of CO2 from CH4 using mixed matrix membranes incorporated with amine functionalized MIL-125 (Ti) nanofiller

This work reported on the fabrication of mixed matrix membranes by incorporating NH2-MIL-125 (Ti) nanofiller into 6FDA–durene polymer matrix for CO2/CH4 separation. The structural properties and morphology of the nanofillers and resultant membranes were investigated by X-ray diffraction, Brunauer Emmett and Teller, field emission scanning electron microscope, energy-dispersive X-ray spectroscopy mapping, thermogravimetric analysis and free fractional volume. The results showed that the CO2 and CH4 single gas permeability, as well as CO2/CH4 ideal selectivity were improved by incorporating NH2-MIL-125 (Ti) into the polymer matrix. Membrane loaded with 7.0wt% of NH2-MIL-125 (Ti) filler showed the highest CO2 permeability of 1115.70 Barrer and CO2/CH4 selectivity of 37.10, surpassing the 2008 Robeson upper bound. Furthermore, improvement of CO2 permeability of 119% and increment of 331% for gas pair selectivity in comparison with pure membrane were achieved. The results obtained in this work is due to the high porosity of nanofillers besides the attraction of amine functional group towards CO2. Overall, incorporation of amine-functionalized MIL-125 (Ti) nanofillers into 6FDA–durene polymer matrix has enhanced the separation performance of the membrane in CO2/CH4 separation.

Evaluation of silica sodalite infused polysulfone mixed matrix membranes during H2/CO2 separation

Global warming and environmental degradation have stimulated the drive towards the capture of large point source carbon emissions and reducing high energy intensity of industrial processes. Mixed membranes infused with high porosity silica sodalite are potential useful for pre-combustion CO2 capture. However, development of high quality mixed matrix membranes is a challenge. In this study, silica sodalite (SSOD) infused polysulfone (PSF) membranes were developed and evaluated for pre-combustion CO2 capture. The SSOD was obtained via topotactic conversion of layered silicates; and the membrane was prepared using the phase inversion method. The physicochemical nature of the SSOD and the SSOD/PSF was checked using XRD, SEM, and N2 physisorption at 77 K. Single gas permeation used to check membrane quality. N2 physisorption shows that the SSOD possesses higher surface area of 56.56 m2/g and pore volume of 0.181 cm3/g, when compared to that of the hydrothermally-synthesized hydroxy sodalite (HSOD) crystals (surface area: 27.43 m2/g; pore volume: 0.084 cm3/g). The SSOD/PSF membrane is asymmetric with higher mechanical strength than the ordinary PSF. Loading the PSF with SSOD enhanced its H2 permeance from 4.9 × 10−7 mol/m2·s·Pa but with a decrease in H2/CO2 separation factor from 2.2 to 0.6. While the enhanced H2 permeance is attributed to the enhanced porosity of the SSOD, the ideal selectivity is low but still within the values reported in literature. Increasing the SSOD loading up to 10 wt% enhanced the quality and performance of the PSF membrane, displaying H2 permeance of 6.5 × 10−7 mol/m2·s·Pa and a separation factor of 1.1. Though results reported in this study are promising, a robust synthesis protocol that will further enhance both the H2 selectivity and H2 permeance of the membrane is required. Furthermore, more studies are required on the process optimization and techno-economic feasibility for pre-combustion CO2 capture.

Thermally annealed polyimide-based mixed matrix membrane containing ZIF-67 decorated porous graphene oxide nanosheets with enhanced propylene/propane selectivity

This work presents a new type of thermally annealed 6FDA-DAM-based mixed matrix membranes (MMMs) containing two-dimensional (2D) ZIF-67-decorated porous graphene oxide nanosheets (ZPGO67) with promising C3H6/C3H8 transport properties. Different characterization techniques, including XRD, DSC, FTIR, and fluorescence spectroscopy, were used to elucidate possible changes in physicochemical properties and structure of MMMs through thermal annealing. C3H6/C3H8 sorption isotherms for pristine 6FDA-DAM and MMM containing ZPGO67 were also measured at different temperatures. Single-gas permeation data indicated that embedding a 20 wt% ZPGO67 filler in the polyimide matrix increased C3H6 permeability from 19.5 Barrer to 58.8 Barrer at 2 bar and 35 °C. The corresponding thermally annealed MMMs showed not only high C3H6/C3H8 permselectivity also excellent resistance to plasticization. For instance, MMM thermally annealed at 400 °C presented C3H6/C3H8 permselectivity of 17.8, at 2 bar and 35 °C, considerably higher than that obtained for the non-annealed MMM. This membrane also showed stable C3H6 permeability of 18.2 Barrer and C3H6/C3H8 permselectivity of 11.3 at 5 bar and 50 °C for 24 h. The high C3H6/C3H8 permselectivity and good anti-plasticization behavior of thermally annealed membranes were mainly attributed to the formation of charge-transfer complexes (CTCs), as evidenced by fluorescence spectroscopy analysis and Tg measurement.

Preparation and Characterization of Mixed Matrix Membrane based on Polysulfone (PSF) and Lanthanum Orthoferrite (LaFeO3) for Gas Separation

The aim of this study is to investigate the effects of polysulfone (PSF) and lanthanum orthoferrite (LaFeO3) incorporated mixed matrix membrane (MMM) on gas permeation and selectivity properties. PSF/LaFeO3 MMMs were prepared with various weights loading of LaFeO3. The membranes obtained were characterized using scanning electron microscope (SEM), thermal gravimetric analysis (TGA) and Fourier-transform infra-red (FT-IR). The gas transport properties of MMM were measured using single gas permeation set up (CO2, CH4, O2 and N2) at ambient temperature, and feed pressure of 2, 4 and 6 bar. The permeation test showed that the mixed matrix membrane exhibited high permeability. With increasing LaFeO3 weight loading to 1.0%, the highest permeability values were 47.74 GPU for CO2, 29.85 GPU for CH4, 57.56 GPU for O2, and 40.66 GPU for N2. The results also showed that by incorporating 1.0wt% of LaFeO3 into PSF matrix, the highest CO2/CH4 and O2/N2 selectivity of 1.60 and 1.42 respectively were obtained. Overall, all the resultants MMM showed higher permeability and selectivity compared to pure PSF membrane.

High-performance SSZ-13 membranes prepared using ball-milled nanosized seeds for carbon dioxide and nitrogen separations from methane

Abstract SSZ-13 membranes with high separation performances were prepared using ball-milled nanosized seeds by once hydrothermal synthesis. Separation performances of SSZ-13 membranes in CO2/CH4 and N2/CH4 mixtures were enhanced after synthesis modification. Single-gas permeances of CO2, N2 and CH4 and ideal selectivities were recorded through SSZ-13 membranes. The effects of temperature, pressure, feed flow rate and humidity on separation performance of the membranes were discussed. Three membranes prepared after synthesis modifications had an average CO2 permeance of 1.16 × 10−6 mol·(m2· s·Pa)−1 (equal to 3554 GPU) with an average CO2/CH4 selectivity of 213 in a 50 vol%/50 vol% CO2/CH4 mixture. It suggests that membrane synthesis has a good reproducible. The membrane also displayed a N2 permeance of 1.07 × 10−7 mol·(m2·s·Pa)−1 (equal to 320 GPU) with a N2/CH4 selectivity of 13 for a 50 vol%/50 vol% N2/CH4 mixture. SSZ-13 membrane displayed stable and good separation performance in the wet CO2/CH4 mixture for a long test period over 100 h at 348 K. The current SSZ-13 membranes show great potentials for the simultaneous removals of CO2 and N2 in natural gas purification as a facile process suitable for industrial application.

Effect of Thermal Soak Time Towards Polyimide Based-Carbon Tubular Membrane

Tubular carbon membrane (TCM) was prepared form BTDA-TDI/MDI (P-84) polyimide (PI) has a main precursor that combines with nanocrystalline cellulose (NCC) through controlled carbonization condition. Consideration of the thermal soaking time through the heating process is needed to maintain the proficiency of resultant TCM’s. Thermal soaking time of 30 minutes, 60 minutes, 90 minutes, and 120 minutes was investigated to study the gas properties of the final TCM’s. In the course of TCM’s separation, single gas permeation experiments of CO2 and N2 are performed to investigate the transport mechanism. The PI / NCC TCM’s developed at 120 min of thermal soak time from this study showed the most impressive CO2/N2 performance, selectivity of 66.32±2.18 respectively.

Silica supported SAPO-34 membranes for CO2/N2 separation

Abstract In this work, SAPO-34 membrane was successfully synthesized on silica support by an optimized secondary growth method which combines ageing and rubbing with the use of enhanced synthesis gel. The enhanced synthesis gel was prepared by the addition of SAPO-34 crystals into the synthesis gel. Results of XRD and IR-ATR analysis of SAPO-34 seeds confirmed the formation of SAPO-34 crystal. SEM analysis showed that the crystal has cubic form and the size was about 200–400 nm. The resultant crystals were then used for the preparation of SAPO-34 membrane on the inner surface of the tubular silica support. XRD and XRF analysis showed that SAPO-34 layer was successfully formed on the membrane support with Si/Al ratio of 0.48–0.49. SEM images showed that the optimized secondary growth method could produce continuous and defect-free SAPO-34 membrane (SAPO-34-M2). In contrast, membrane prepared by rubbing method with conventional synthesis gel (SAPO-34-M1) displayed discontinued and defects layer. In single-gas permeation test, SAPO-34-M2 membrane showed two regions of N2 flux indicating the drastic effect of concentration polarization on N2 permeation at higher pressure. The concentration polarization phenomenon resulted in a decrease of CO2/N2 selectivity with increasing transmembrane pressure. It was demonstrated by single-gas permeation test that the SAPO-34-M2 membrane could surpass the Robeson plot (2008) for CO2/N2 separation (permeance = 2.01 × 10−6 mol/m2 s Pa; the highest selectivity = 53). The results showed that the prepared SAPO-34 membrane could be an alternative for CO2/N2 separation.

Influence of synthesis parameters on preparation of AlPO-18 membranes by single DIPEA for CO2/CH4 separation

CO2-selective AlPO-18 membranes were prepared hydrothermally on macroporous supports with a low-cost template N, N-diisopropylethylamine (DIPEA). The effects of synthesis parameters (such as gel dilution, synthesis temperature, synthesis time and aging time) on the structure, morphology and single gas permeation properties of CO2 and CH4 through AlPO-18 membranes were investigated in detail. The synthesis conditions had little effect on the membrane morphology but strongly affected the CO2/CH4 gas permeation properties of as-synthesized AlPO-18 membranes. The best membrane was obtained at a synthesis temperature of 433 K for 15 h after aging the precursor gel (1Al2O3: 1P2O5: 4DIPEA: 120H2O: 4IPA) for 24 h. The CO2 single gas permeance of this membrane was 1.1 × 10−6 mol/(m2 s Pa), with an ideal CO2/CH4 selectivity of 56 at 303 K and a 0.1 MPa pressure drop. The mixed gas CO2 permeance of same membrane with an equimolar CO2/CH4 mixture was 1.1 × 10−6 mol/(m2 s Pa) with a CO2/CH4 selectivity of 75 at 303 K and a 0.2 MPa pressure drop.

A lithium–aluminosilicate zeolite membrane for separation of CO2 from simulated blast furnace gas

In this study, for the first time, the small pore size (0.28 × 0.37 nm) Li–aluminosilicate zeolite membrane was synthesized for separation of CO2 from H2–CO2 and H2–CO2–N2–CO (simulated blast furnace gas) gas mixtures. Li–aluminosilicate membranes were prepared on porous clay alumina tubes by sonication mediated hydrothermal method using pre synthesized zeolite powders as seeds. The zeolite formation was confirmed by X-ray diffraction pattern and FESEM analysis. The scanning electron micrograph of the membrane, suggested the uniformity of the dense structure of the membrane. Single-gas and mixed-gas permeation experiments through membranes were carried out at 25 °C using H2, CO2 and N2 single-component gases and mixture of H2–CO2, H2–CO2–N2–CO for simulated blast furnace gas composition. Synthesized Li–aluminosilicate zeolite shows appreciable CO2 adsorption capacity at liquid nitrogen temperature compared with other reported zeolites. In case of single gas permeation, membrane shows usual pattern of permeation. For mixture gas, separation efficiency of Li–zeolite membrane increased abruptly compared to the other zeolite membranes. The maximum CO2–H2, CO2–N2 and CO2–CO separation selectivities were found to be 78, 8.7 and 67.3 respectively, with permeance of H2, CO2 and N2 2.21 × 10−7, 1.01 × 10−7 and 0.8 × 10−7 mol m−2 s−1 Pa−1 at 25 °C respectively.

SiC mesoporous membranes for sulfuric acid decomposition at high temperatures in the iodine-sulfur process.

Inorganic microporous materials have shown promise for the fabrication of membranes with chemical stability and resistance to high temperatures. Silicon-carbide (SiC) has been widely studied due to its outstanding mechanical stability under high temperatures and its resistance to corrosion and oxidation. This study is the first to prepare mesoporous SiC membranes for use in sulphuric acid decomposition to achieve thermochemical water splitting in the iodine–sulfur process. Single-gas permeation was carried out to confirm the stability of this mesoporous membrane under exposure to steam and H2SO4 vapor. Benefiting from the excellent chemical stability of the α-Al2O3 membrane support and the SiC particle layer, the SiC membrane exhibited stable gas permeance without significant degradation under H2SO4 vapor treatment at 600 °C. Additionally, with extraction, the membrane reactor exhibited an increased conversion from 25 to 41% for H2SO4 decomposition at 600 °C. The high performance combined with outstanding stability under acidic conditions suggests the developed SiC membrane is a promising candidate for H2SO4 decomposition in a catalytic membrane reactor.

Development of mixed matrix membrane comprising titanium (IV) oxide dispersed with octaisobutyl polyhedral oligomeric silsesquioxane

In designing mixed matrix membranes (MMMs) to improve gas separation performance, inorganic fillers such as titanium (IV) oxide (TiO2) nanoparticles are commonly added due to their excellent intrinsic properties and high affinity towards CO2. However, the addition of TiO2 nanoparticles causes the formation of agglomerates which deteriorate the gas separation properties of the membrane due to their high surface energy and Van der Waals forces. In this study, MMMs comprising octaisobutyl polyhedral oligomeric silsesquioxane (OPOSS) incorporated with TiO2 nanoparticles were successfully developed using phase inversion technique. MMMs were synthesized at different loadings of TiO2 and OPOSS. The effectiveness of OPOSS as a dispersant was determined by using SEM, EDS and single gas permeation analysis. The optimum amount of TiO2-OPOSS in the THF/DMAc casting solution was at 4wt% TiO2 and 2wt% of OPOSS, as the agglomeration of nanoparticles did not occur based on the morphology and gas separation performance. The membrane with the highest performance was achieved by 4/2-T/OPOSS, which is at 1.8 of CO2/CH4 gas selectivity. Based on the findings, it can be concluded that the OPOSS did play an important role in enhancing the dispersion of TiO2 nanoparticles in the polymer matrix as the TiO2 agglomerates were not seen upon addition of OPOSS.

ADVANCED IN CARBON MEMBRANE BY RELATING TO COATING-CARBONIZATION-CYCLES FOR OXYGEN PERFORMANCE

This work discusses the creation and assessment of rounded carbon membrane arranged from P84 co-polyimide mixes with Nanocrystalline cellulose (NCC). In light of earlier examinations, it defined the theory that rounded carbon membrane execution can be controlled by controlling the carbonization parameters. The focal point of this investigation is to acquaint compelling dip-coating strategies with deliver superior rounded carbon membrane. In light of the result of this examination, the coating carbonization cycle (1, 2, 3, and multiple times) has been distinguished as real effect on the separation productivity. Gas separation performance and transport instrument of the carbon membranes were enough assessed by single gas permeation of O2, and N2. In this exploration, use of 2-cycles of coating carbonization has brought about carbon membrane with the most elevated selectivity and O2 penetrability which are 9.29±2.54 and 29.92±1.44 GPU, individually.

Improved performance of vacuum membrane distillation in desalination with zeolite membranes

A supported Mordenite Framework Inverted (MFI) zeolite membrane with a length of 30 cm was synthesized by the secondary growth method using a fast heating profile for the template removal (calcination) step. The presence of defects into the zeolite layer (before and after calcination) was assessed by means of single gas permeation tests. Afterwards, the membrane performance was evaluated in Vacuum Membrane Distillation (VMD) for desalination. Two cleaning procedures were applied between consecutive experiments on salty solutions and their efficiency compared. NaCl rejections of 99.9% were achieved for feeds ranging from 0.2 M to 0.9 M, dropping down to 97% for the 1.2 M feed. The highest trans-membrane flux (20.6 kg m−2 h−1) was measured for 0.2 M feed, by working at 70 °C and 120 L/h.

Co-based zeolitic imidazolate framework ZIF-9 membranes prepared on α-Al2O3 tubes through covalent modification for hydrogen separation

Hydrogen has been regarded as the most promising clean and renewable energy. Beside the production of the hydrogen, the separation of hydrogen is also an import issue before it can be used in fuel cells. Membrane-based separation technologies have gained considerable attentions due to its high efficiency and low energy consumption. Zeolite imidazolate framework (ZIF) membranes have drawn intense interest due to their zeolite-like properties such as permanent porosity, uniform pore size and exceptional thermal and chemical stability. It is rather challenged to prepare well-intergrown Co-based zeolitic imidazolate frameworks (ZIFs) membranes on porous α-Al2O3 tubes since Co-based ZIFs prefer to form crystals in the synthesis solution rather than grow as membrane layer on the support surface. In this work, we report the preparation of high-quality ZIF-9 membrane with high H2/CO2 selectivity and excellent thermal stability by using 3-aminopropyltriethoxysilane (APTES) as a covalent linker to modify the α-Al2O3 tube. Due to the formation of covalent bonds between APTES and ZIF-9, ZIF-9 nutrients are bound to the support surface, thus promoting the growth of dense and phase-pure ZIF-9 membrane with a thin thickness of about 4.0 μm. The gas separation performances of the ZIF-9 membrane were evaluated by single gas permeation and mixture gas separation of H2/CO2, H2/N2 and H2/CH4, respectively. The mixture separation factors of H2/CO2, H2/CH4, and H2/N2 of the ZIF-9 membrane are 21.5, 8.2 and 14.7, respectively, which by far exceeds corresponding Knudsen coefficients. Moreover, the as-prepared ZIF-9 membrane exhibits excellent stability at a relatively broad range of operating temperature, which is beneficial for the industrial application of hydrogen separation or further membrane reactor.

Controlled Carbonization Heating Rate for Enhancing CO2 Separation Based on Single Gas Studies

Concerns about the impact of greenhouse gas have driven the development of new separation technology to meet CO2 emission reduction targets. Membrane-based technologies using carbon membranes that are able to separate CO2 efficiently appears to be a competitive method. This research was focused on the development of carbon membranes derived from polymer blend of polyetherimide and polyethylene glycol to separate CO2 rendering it suitable to be used in many applications such as landfill gas purification, CO2 removal from natural gas or flue gas streams. Carbonization process was conducted at temperature of 923 K and 2 h of soaking time. To enhance membrane separation properties, pore structure was tailored by varying the carbonization heating rates to 1, 3, 5, and 7 K / min. The effect of carbonization heating rate on the separation performance was investigated by single gas permeabilities using CO2 , N2 , and CH4 at room temperature. Carbonization heating rate of 1 K / min produced carbon membrane with the most CO2 / N2 and CO2 / CH4 selectivity of 38 and 64, respectively, with the CO2 permeability of 211 barrer. Therefore, carbonization needs to be carried out at sufficiently slow heating rates to avoid significant loss of selectivity of the derived carbon membranes.

Synthesis and evaluation of a nanocomposite hydroxy sodalite/ceramic (HS/ceramic) membrane for pre-combustion CO2 capture: Characterization and permeation test during CO2/H2 separation

Greenhouse gases (GHGs), secondary products from combustion of fossil fuel, have been instrumental to global warming which causes climate change. However, carbon capture, storage and utilization (CCSU) is one of the promising ways to reducing CO2 emission from large point sources via pre-combustion CO2 capture. Membrane technology has been identified as one of the promising technologies for pre-combustion CO2 capture, but availability of membranes with high membrane integrity (high CO2 flux, high selectivity, good chemical and thermal stability) is a major challenge in advancing this technology. Against this background, synthesis and gas permeation of a nanocomposite hydroxy sodalite/ceramic (HS/α-Al2O3) membrane, prepared via pore-plugging hydrothermal synthesis technique (PPH), are hereby reported. Morphology, purity of the sodalite particles (obtained from the bottom of the autoclave) and quality of the as-prepared membrane were checked using scanning electron microscopy (SEM), X-ray Diffraction (XRD), and Basic Desorption Quality Test (BDQT) (for the membrane). Single gas permeation experiments were carried out on the membrane at 298 K via Wicke-Kallenbach method (W-K) using pure component CO2 and H2 to gain insight into separation performance of the membrane. The single gas permeation results reveal H2 permeance and CO2 permeance of 7.37 × 10−8 mol·s−1·m−2·Pa−1 and 1.14 × 10−8 mol·s−1·m−2·Pa−1, respectively, with ideal selectivity of 6.46. In addition, H2 permeation through the membrane was adequately described with the well-known Maxwell-Stefan (M-S) model.

Synthesis and gas permeation properties of chabazite-type titanosilicate membranes synthesized using nano-sized seed crystals

Abstract Chabazite (CHA)-type zeolite membranes have received considerable attention regarding their high permeance and separation performance. A recent report detailing a unique preparation procedure for a CHA-type titanosilicate (Ti-CHA) zeolite—in which titanium heteroatoms were incorporated into the zeolite framework by substitution of aluminum—demonstrates excellent physico-chemical properties when compared with conventional aluminosilicate CHA-type zeolites. In this study, the synthesis of Ti-CHA zeolite membranes (Ti-CHA membrane) was investigated. The Ti-CHA membrane was synthesized on an alumina support via a secondary growth method using Ti-CHA zeolite seed crystals. The Ti-CHA membrane properties were studied as a function of seed crystal size. The average particle diameter was observed to reduce from 2.3 μm to 450 nm by increasing the loading of Ti-CHA into the synthesis gel. Regardless of the seed crystal particle size, the presence of CHA-type zeolites on the alumina support was confirmed by x-ray diffraction. UV–Vis demonstrated the incorporation of titanium heteroatoms into the zeolite framework. The results indicated the successful synthesis of the Ti-CHA membrane regardless of the seed crystal particle size. Additionally, the membrane thickness decreased by using the seed crystal. Single gas permeation tests showed that the thinnest Ti-CHA membrane prepared in this study exhibited a relatively high CO2 permeance of 1.5 × 10−6 mol m−2 s−1 Pa−1, compared with that of previously reported CHA-type zeolite membranes. The influence of moisture on the separation performance of the Ti-CHA membrane was evaluated in the presence of gas mixtures composed of CO2, methane and H2O ranging from 0.1 to 5 vol%. In the presence of 1 vol% H2O, the CO2 permeance and selectivity were only marginally reduced as a result of the highly hydrophobic pore structure.