JP7240756B2 - Gas separation membrane containing different types of zeolite and method for producing the same - Google Patents

Description

The present invention relates to a gas separation membrane containing MWW-type zeolite and DDR-type zeolite and a method for producing the same,
Specifically, it relates to a gas separation membrane comprising MWW zeolite epitaxially grown with DDR zeolite or DDR zeolite epitaxially grown with MWW zeolite, or a method for producing the same.

Zeolite is a catalyst for conversion of methanol to gasoline, denitrification of soot, etc., and is alumina having a regular three-dimensional framework structure in which tetrahedra of SiO ₄ and AlO ₄ ⁻ are combined in a geometric form. - It is a crystalline molecular body of silica, characterized in that the tetrahedrons are connected by sharing oxygen, the skeleton has channels, and the cavities are connected to each other. Due to these characteristics, zeolites have excellent ion exchange properties, and are used in various applications such as catalysts, adsorbents, molecular bodies, ion exchange agents, and separation membranes.

In the case of conventional zeolite separation membranes, defects larger than the pore size inherent to zeolite, which are inevitably generated during the production of separation membranes, greatly reduce the separation performance, making it difficult to produce high-performance separation membranes. was difficult.

Therefore, there is a demand for the development of a separation membrane that fills defects larger than the pore size inherent to zeolite and has excellent separation performance.

Korean Patent No. 10-0861012

SUMMARY OF THE INVENTION An object of the present invention is to provide a gas separation membrane in which different kinds of zeolites are alternately epitaxially grown, and a method of manufacturing the same. Specifically, the present invention provides a gas separation membrane in which DDR type zeolite is epitaxially grown from MWW type zeolite or MWW type zeolite is epitaxially grown from DDR type zeolite.

The present invention includes one or more MWW-type zeolite and one or more DDR-type zeolite, wherein the MWW-type zeolite and the DDR-type zeolite are alternately provided, and the MWW-type zeolite and the DDR-type zeolite are provided alternately. provides MWW/DDR type gas separation membranes, including those that are epitaxially grown.

Further, the present invention provides a plurality of first zeolite particles produced by a hydrothermal synthesis method using a first zeolite precursor solution containing a first structure-inducing agent and a first raw material on a support. , a first zeolite forming step to form a first zeolite; and a second zeolite precursor solution comprising a second structure directing agent and a second raw material on the first zeolite in a hydrothermal method. a second zeolite forming step of growing the second zeolite to
The first or second raw material contains at least one or more of Si and Al, respectively,
The first zeolite is provided in the form of a plurality of particles on the support, and the second zeolite is epitaxially grown on the first zeolite. provide a way.

The gas separation membrane according to the present invention, in which different types of zeolites are epitaxially grown using the structural continuity of MWW-type zeolite and DDR-type zeolite, can have excellent separation efficiency.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows sectional drawing of the gas separation membrane which concerns on one Example of this invention. 1 is a flowchart illustrating a method of manufacturing a gas separation membrane according to one embodiment of the invention; 1 is a schematic diagram showing a method of manufacturing a gas separation membrane according to one embodiment of the present invention; FIG. FIG. 4 is an image (ae) taken with a scanning electron microscope (SEM) and a graph (f) obtained by X-ray diffraction analysis of a gas separation membrane according to an embodiment of the present invention; 1 is an image showing a schematic structural model capable of epitaxial growth of DDR zeolite from MWW zeolite at the interface of a gas separation membrane according to an embodiment of the present invention; 4 is an image taken with a scanning electron microscope (SEM) of a gas separation membrane according to another embodiment of the present invention; 4 is a graph of X-ray diffraction analysis of a gas separation membrane according to another embodiment of the present invention; X-ray diffraction analysis graph (a), transmission electron microscope (TEM) image (b), high-resolution transmission electron microscope (HR-TEM) image (c) and fast Fourier analysis of the gas separation membrane according to one embodiment of the present invention 4 is an image of a transform (FFT) pattern (d); 4 is an image taken with a scanning electron microscope (SEM) of a gas separation membrane according to still another embodiment of the present invention; 4 is a graph of X-ray diffraction analysis of a gas separation membrane according to still another embodiment of the present invention; 1 is an image of a gas separation membrane according to a comparative example of the present invention, taken with a scanning electron microscope (SEM); 4 is a graph confirming the carbon dioxide separation capacity of a gas separation membrane according to an example of the present invention; 4 is a graph confirming the carbon dioxide separation ability of a gas separation membrane according to another example of the present invention; 4 is a graph confirming carbon dioxide separation performance under dry and wet conditions of a gas separation membrane according to an embodiment of the present invention; 4 is an image confirming the hydrophobicity of the gas separation membrane according to an embodiment of the present invention; Scanning electron microscope (SEM) and fluorescence confocal optical microscope (FCOM) images of a gas separation membrane according to an embodiment of the present invention, wherein (a) lines and (c) lines are cross-sectional images, (b) lines and (d) Lines are top-view images. FIG. 4 is an image of a fluorescence confocal optical microscope (FCOM) characteristic analysis of a gas separation membrane according to an embodiment of the present invention; FIG. FIG. 10 is an image of a fluorescence confocal optical microscopy (FCOM) analysis of a gas separation membrane according to another embodiment of the present invention; FIG. 1 is an image schematically showing a defect structure of a gas separation membrane according to an embodiment of the present invention; FIG. 10 is an image analyzing the characteristics of gas separation membranes according to other examples and comparative examples of the present invention with a fluorescence confocal optical microscope (FCOM); FIG.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described in more detail with reference to the accompanying drawings in order to explain the present invention more specifically. This invention may, however, be embodied in other forms and should not be construed as limited to the embodiments set forth herein.

The zeolite separation membrane has a uniform size of micropores and can act as a molecular body. When the zeolite separation membrane is applied to the separation process, it is expected that the energy used in the existing separation process can be reduced. Although 253 zeolite structures have been proposed to date, a few zeolite (eg MFI, FAU, CHA, DDR, MOR, LTA) structures have nevertheless been synthesized for separation membranes.

When synthesizing the separation membrane, the method of synthesizing the separation membrane through secondary growth after forming a uniform seed layer is mainly used. It consisted of a structure

DDR-type zeolite has a pore size of about 0.36×0.44 nm ² and can selectively separate CO ₂ (0.33 nm) through the role of molecular bodies. However, DDR-type zeolite is difficult to synthesize seed particles, has low reproducibility, and is difficult to form a seed layer of a separation membrane. .

In addition, the MWW-type zeolite is a plate-shaped particle, and when oriented in the c-direction, it must pass vertically through 6-membered ring (MR) pores (0.28 nm), so it is proposed as a hydrogen selective separation membrane. rice field. However, it is difficult to form a separation membrane oriented in the 6MR pore direction, and there has been no report on the formation and separation performance of a continuous separation membrane.

The present invention comprises one or more MWW-type zeolites and one or more DDR-type zeolites,
The MWW-type zeolite and the DDR-type zeolite are provided alternately, and at least one of the MWW-type zeolite and the DDR-type zeolite is epitaxially grown. A /DDR structural gas separation membrane is provided.

The MWW/DDR structure is a structure in which MWW-type zeolite and DDR-type zeolite are intergrown, and one or more MWW-type zeolites are epitaxially grown with one or more DDR-type zeolites, or one One or more MWW type zeolites are epitaxially grown on the above DDR type zeolite.

For example, in the gas separation membrane of the present invention, the MWW-type zeolite and the DDR-type zeolite independently form layers and are alternately and repeatedly provided, and the thickness of the gas separation membrane is 0. .1-50 μm, 0.1-30 μm, 0.5-10 μm, or 0.5-3 μm.

As an example, DDR type zeolite is epitaxially grown on the MWW type zeolite by a hydrothermal synthesis method under a first condition, or MWW type zeolite is hydrothermally synthesized on the DDR type zeolite under a second condition. can be provided epitaxially grown by the method.

The first condition is a temperature of 100° C. to 200° C., 100° C. to 180° C., 120° C. to 160° C., or 130° C. to 160° C. for 0.5 days to 15 days, 1 day to 15 days, or comprising hydrothermally synthesizing for 1 day to 10 days, wherein the second condition is 100° C. to 200° C., 100° C. to 180° C., 120° C. to 160° C., or 130° C. to 150° C. at a temperature of 0 .5 to 15 days, 1 to 15 days, or 1 to 11 days of hydrothermal synthesis.

The MWW-type zeolite may have a standard Si:Al molar ratio of 100:0-10 or 100:1-10.

The DDR-type zeolite may have a standard Si:Al molar ratio of 100:0-10 or 100:0-1.

As described above, the gas separation membrane according to the present invention has a structure in which different types of zeolites are alternately and mutually grown, and the different types of zeolites are epitaxially grown with each other. gas (CO ₂ ) can be further improved compared to existing separation membranes.

Further, in the gas separation membrane of the present invention, when the DDR type zeolite is provided on the MWW type zeolite in the first direction X as shown in (a) of FIG. The MWW-type zeolite particles have an average length T1 parallel to the first direction of 10 nm to 1 μm, 100 nm to 1 μm, 10 nm to 800 nm, 20 nm to 500 nm, 10 nm to 100 nm, or 50 nm to 100 nm.

Further, as shown in (b) of FIG. 1, when the MWW-type zeolite is provided on the DDR-type zeolite in the first direction X, the DDR-type zeolite is composed of a group of a plurality of DDR-type zeolite particles, The DDR type zeolite particles have an average length T2 parallel to the first direction of 0.1 μm to 10 μm, 0.1 μm to 5 μm, 0.5 μm to 5 μm, 1 μm to 5 μm, 0.5 μm to 3 μm, or 0 .1 μm to 1 μm.

Further, as shown in FIG. 1(c), the plurality of MWW-type zeolite particles can be multi-layered to form a first zeolite, as shown in FIG. 1(d). As such, the plurality of DDR-type zeolite particles may be stacked in a multi-layer to form a first zeolite.

The MWW-type zeolite particles or the DDR-type zeolite particles can serve as seeds for forming a second zeolite with the first zeolite particles.

In addition, as shown in FIG. 2, the present invention provides a plurality of first zeolites produced by a hydrothermal synthesis method using a first zeolite precursor solution containing a first structure-inducing agent and a first raw material. hydrothermally using a first zeolite forming step of providing particles on a support to form a first zeolite; and a second zeolite precursor solution comprising a second structure directing agent and a second raw material; a second zeolite forming step of growing a second zeolite on said first zeolite, wherein said first or second source material is at least one of Si and Al, respectively; said first zeolite is provided on said support in the form of a plurality of particles, and said second zeolite is epitaxially grown on said first zeolite. A method for manufacturing a separation membrane is provided.

Furthermore, in the method for producing a gas separation membrane according to the present invention, as shown in FIG. 3, between the first zeolite forming step and the second zeolite forming step, a plurality of A buffer portion forming step of forming a buffer portion covering at least a portion of the first zeolite particles can be included.

The buffer portion forming step can grow a second zeolite on the plurality of particles of the first zeolite by a hydrothermal synthesis method using the first zeolite and a buffer portion precursor solution.

The buffer portion forming step can be omitted. Through the step of forming the buffer portion, an interface between the first and second zeolites having different structures is epitaxially grown, thereby further improving structural safety.

Each of the first and second raw materials contains at least one of Si and Al.

The raw material containing Si may include at least one of silica (SiO ₂ ), monomeric silica, fumed silica, and colloidal silica.

The Al-containing material may include an aluminum oxide salt, and specifically, the Al-containing material may be NaAl ₂ O ₃ .

Specifically, when the first or second zeolite precursor solution is a solution for growing MWW-type zeolite, the first or second raw material contains Si and Al, and the first or second zeolite precursor solution contains Si and Al. The molar concentration ratio of the zeolite precursor solution is Si:Al:structuring agent:solvent=100:0-10:10-500:500-20000, or 100:1-10:10-500:500-20000. can contain.

Further, when the first or second zeolite precursor solution is a solution for growing DDR type zeolite, the first or second raw material contains Si, Al, and the first or second zeolite precursor solution is The molar concentration ratio of the body solution can be Si:Al:structuring agent:solvent=100:0-10:1-200:500-20000, or 100:0-1:1-200:500-20000 .

The solvent can include distilled water, deionized water, or ethanol.

The first and second structure directing agents are independently hexamethyleneimine (HMI), piperidine, adamantylamine (1-adamantylamine), ethylenediamine, methyltropinium salts, 1-TMAdaOH (N,N,N-trimethyl-1-adamantylammonium hydroxide), TMAdaBr (N,N,N-trimethyl-1-adamantylammonium bromide), TMAdaF (N,N,N-trimethyl-1-adamantyl), ＴＭＡｄａＣｌ（Ｎ，Ｎ，Ｎ－ｔｒｉｍｅｔｈｙｌ－１－ａｄａｍａｎｔｙｌａｍｍｏｎｉｕｍ ｃｈｌｏｒｉｄｅ）、ＴＭＡｄａＩ（Ｎ，Ｎ，Ｎ－ｔｒｉｍｅｔｈｙｌ－１－ａｄａｍａｎｔｙｌａｍｍｏｎｉｕｍ ｉｏｄｉｄｅ）、ＴＥＡＯＨ（ｔｅｔｒａｅｔｈｙｌａｍｍｏｎｉｕｍ ｈｙｄｒｏｘｉｄｅ）、ＴＥＡＢｒ（ｔｅｔｒａｅｔｈｙｌａｍｍｏｎｉｕｍ ｂｒｏｍｉｄｅ）、ＴＥＡＦ（ｔｅｔｒａｅｔｈｙｌａｍｍｏｎｉｕｍ ｆｌｕｏｒｉｄｅ）、 TEACl (tetraethylammonium chloride), TEAI (tetraethylammonium iodide), dipropylamine, and cyclohexylamine.

The methyltropinium salt is methyltropinium iodide.
iodide), methyltropinium fluoride, methyltropinium chloride, methyltropinium bromide, and methyltropinium hydroxide including one or more

Specifically, among the first and second structure inducers, the structure inducer for growing MWW-type zeolite is hexamethyleneimine (HMI), piperidine, TMAdaOH (N, N, N-trimethyl-1-adamantylammonium hydroxide), TMAdaBr (N,N,N-trimethyl-1-adamantylammonium bromide), TMAdaF (N,N,N-trimethyl-1-adamantylammonium bromide) (N,N,N-trimethyl-1-adamantylammonium fluoride) trimethyl-1-adamantylammonium chloride), and TMAdaI (N,N,N-trimethyl-1-adamantylammonium iodide).

Further, the structure-inducing agent for growing DDR-type zeolite among the first and second structure-inducing agents is any one of methyltropinium salt, adamantylamine (1-adamantylamine), and ethylenediamine can be one or more.

The support includes α-alumina, γ-alumina, polypropylene, polyethylene, polytetrafluoroethylene, polysulfone, polyimide, silica, glass, mullite, zirconia, titania, yttria. , ceria, vanadia, silicon, stainless steel, carbon, calcium oxide, and phosphorous oxide.

The first zeolite forming step uses a first zeolite precursor solution containing a first structure-inducing agent and a first raw material to support the plurality of first zeolite particles produced by a hydrothermal synthesis method. Forming the first zeolite in preparation on the body.

Said first zeolite formation step can consist of two steps, as follows:
(1) A first zeolite particle forming step of forming a plurality of first zeolite particles by a hydrothermal synthesis method under a first condition or a second condition using the first zeolite precursor solution; and ( 2) can include a first zeolite forming step of depositing said first zeolite particles on a support using a suspension comprising said forming plurality of first zeolite particles.

When the first zeolite precursor solution is a solution for forming MWW-type zeolite particles, the first raw material contains Si and Al, and the molar concentration ratio of the first zeolite precursor solution is Si:Al:structure inducer:solvent=100:0-10:10-500:500-20000 or 100:1-10:10-500:500-20000. Specifically, the first zeolite precursor solution for forming the MWW-type zeolite particles is Si:Na:Al:structure inducer:solvent=100:10-100:0-10:10-500:500- 20000, or a solution mixed in a ratio of 100:10-100:1-10:10-500:500-20000.

Further, when the first zeolite precursor solution is a solution for forming DDR type zeolite particles, the first raw material contains Si and Al, and the molar concentration ratio of the first zeolite precursor solution is includes Si:Al:structure directing agent:solvent=100:0-10:1-200:500-20000 or 100:0-1:1-200:500-20000. Specifically, the first zeolite precursor solution for forming the DDR-type zeolite particles is SiO ₂ :Na:Al:structuring agent:solvent=100:10-100:0-10:1-200:500 to 20000, or 100:10 to 100:0 to 1:1 to 200:500 to 20000.

The first condition is a condition for forming DDR type zeolite particles, and the temperature is 100° C. to 200° C., 100° C. to 180° C., 120° C. to 160° C., or 130° C. to 160° C. including hydrothermal synthesis for 5 to 15 days, 1 to 15 days, or 1 to 10 days, wherein the second conditions are conditions for forming MWW-type zeolite particles, and Hydrothermal synthesis at a temperature of 200°C, 100°C to 180°C, 120°C to 160°C, or 130°C to 150°C for 0.5 days to 15 days, 1 day to 15 days, or 1 day to 11 days Including.

The first zeolite particle formation step is heating and calcination ( Further steps of calcination can be performed.

In addition, the first zeolite forming step uses a suspension obtained by mixing a plurality of the manufactured first zeolite particles with a solvent containing at least one of anhydrous toluene, ethanol, and distilled water. A plurality of first zeolite particles can be deposited in one or more layers on a support to form the first zeolite.

When forming the first zeolite under the conditions as described above, as shown in FIG. , 10 nm to 800 nm, 20 nm to 500 nm, 10 nm to 100 nm, or 50 nm to 100 nm, can be formed to form a first zeolite, said first zeolite particles 100 may be MWW-type zeolite particles. Also, as shown in FIG. 1(c), the plurality of first zeolite particles 100 may be multi-layered on the support S to form the first zeolite.

Alternatively, as shown in FIG. 1(b), the average length T2 parallel to the first direction X on the support S is 0.1 μm to 10 μm, 0.1 μm to 5 μm, 0.5 μm to 5 μm, 1 μm. First zeolite particles 100 that are ~5 μm, 0.5 μm to 3 μm, or 0.1 μm to 1 μm can be formed to form a first zeolite, said first zeolite particles 100 being of the DDR type It can be zeolite particles. Also, as shown in (d) of FIG. 1, the plurality of first zeolite particles 100 may be multi-layered on the support S to form the first zeolite.

The first zeolite particles can act as seeds for forming the second zeolite.

The thickness of the first zeolite can be 0.1 to 10 μm, 0.5 to 10 μm, 0.1 to 1 μm, or 1 to 10 μm. The thickness of the first zeolite is 0.1-1 μm, and when the first zeolite is a DDR type zeolite, the thickness of the first zeolite can be 1-10 μm.

When forming the first zeolite with such a thickness, the second zeolite can be grown to form a continuous crystalline phase with the first zeolite particles.

The first zeolite forming step is heating and calcining at a temperature of 400-500° C. at a rate of increase of 0.2-1.0° C./min for 12-40 hours after hydrothermal synthesis. can be further done.

Through the calcination process as described above, the first zeolite may have increased bonding strength with the porous support layer, and may form a stable first zeolite.

The step of forming the buffer portion comprises epitaxially growing the second zeolite so as to form a continuous crystal phase with the plurality of first zeolite particles of the first zeolite, and forming a precursor for three-dimensionally growing the second zeolite. act as a body.

In the buffer portion forming step, the first and second zeolites are different types of zeolites, and the zeolite structure formed by the buffer portion precursor solution is the same as the second zeolite structure. be able to.

Specifically, the buffer part forming step is a buffer part precursor in which adamantylamine:ethylenediamine:fumed silica:solvent is mixed at a molar concentration of 1-20:100-200:100:1000-20000. A solution can be used to provide the buffer portion in a hydrothermal synthesis method. More specifically, 1 A buffer portion can be formed on the first zeolite by a hydrothermal synthesis method for 1 to 5 days, or 1 to 3 days.

In the step of forming the buffer portion, the second zeolite particles can be epitaxially formed from the first zeolite particles by forming the buffer portion by the hydrothermal synthesis method under the conditions described above.

The buffer part forming step further includes a step of heating and calcining at a temperature of 450 to 550 ° C. at a rate of increase of 0.2 to 0.5 ° C./min for 12 to 40 hours after hydrothermal synthesis. It can be carried out.

As described above, the second zeolite particles produced through the calcination process can be thermally activated, and the second zeolite particles stably have a strong bonding force with the first zeolite. be able to.

The second zeolite forming step is a hydrothermal synthesis method using a second zeolite precursor solution containing a second structure-inducing agent and a second raw material under the first condition or the second condition, growing a second zeolite on the first zeolite;

When the second zeolite precursor solution is a solution for forming MWW-type zeolite, the second raw material contains Si and Al, and the molar concentration ratio of the second zeolite precursor solution is Si :Al:structure inducer:solvent=100:0-10:10-500:500-20000 or 100:1-10:10-500:500-20000. Specifically, the second zeolite precursor solution for forming the MWW-type zeolite is Si:Na:Al:structuring agent:solvent=100:10-100:0-10:10-500:500-20000 , or a solution mixed in a ratio of 100:10-100:1-10:10-500:500-20000.

Further, when the second zeolite precursor solution is a solution for forming DDR type zeolite, the second raw material contains Si and Al, and the molar concentration ratio of the second zeolite precursor solution is , Si:Al:structure inducer:solvent=100:0-10:1-200:500-20000, or 100:0-1:1-200:500-20000. Specifically, the second zeolite precursor solution for forming the DDR-type zeolite is Si:Na:Al:structuring agent:solvent=100:10-100:0-10:1-200:500-20000 , or in a ratio of 100:10-100:0-1:1-200:500-20000.

In the second zeolite precursor solution, the structure directing agent can be the methyltropinium salt, and as described above, using the second zeolite precursor solution containing the methyltropinium salt, hydrothermal Synthetically, the second zeolite can be grown with a continuous face orientation.

Specifically, as shown in FIG. 1, a second zeolite layer is formed by forming one surface while growing a second zeolite from a plurality of first zeolite particles 100 formed on the support S. 200, and when the plurality of first zeolite particles 100 are MWW-type zeolite particles as in FIG. 1(a), the second zeolite layer 200 is formed of DDR-type zeolite. As shown in FIG. 1(c), a second zeolite layer 200 is formed on the first zeolite in which the plurality of first zeolite particles 100 are multi-layered. be able to.

Alternatively, if the plurality of first zeolite particles 100 are DDR type zeolite particles as in FIG. 1(b), the second zeolite layer 200 may be formed of MWW type zeolite. (d), a second zeolite layer 200 can be formed on the first zeolite in which the plurality of first zeolite particles 100 are multi-layered.

The first condition is a temperature of 100° C. to 200° C., 100° C. to 180° C., 120° C. to 160° C., or 130° C. to 160° C. for 0.5 days to 15 days, 1 day to 15 days, or hydrothermally for 1 day to 10 days, wherein said second conditions are at a temperature of 100°C to 200°C, 100°C to 180°C, 120°C to 160°C, or 130°C to 150°C , 0.5-15 days, 1-15 days, or 1-11 days.

After the second zeolite forming step, the step of rapid heat treatment at a temperature of 700-1200° C. for 10 seconds to 5 minutes may be further included.

As described above, through the rapid heat treatment step, the zeolite is shrunk, the support is expanded, and the width of cracks in the zeolite is reduced, thereby improving the gas permeation selectivity.

Examples of the present invention are described below. However, the following examples are merely preferred examples of the present invention, and the scope of the present invention is not limited by the following examples.

[Example]
The zeolites of Examples 1-2 of the present invention and Comparative Examples 1-11 were synthesized as follows, and the results are summarized in Table 1 below.

Synthesis of MWW-type zeolite particles
First, NaOH (98% pellet, Sigma-Aldrich) and sodium aluminate (NaAlO ₂ , Sigma-Aldrich) were added to deionized water (DI) in a plastic bottle. Hexamethyleneimine (HMI, 97% Sigma-Aldrich) was then added to the mixture. Fumed silica (CAB-O-SIL M-5, Cabot Corporation) was slowly added to the solution with stirring. The final mass composition of the mixture is 1 _SiO2 :0.1 NaOH:0.03 _NaAlO2 :0.8 HMI:13.1 _H2O . The mixture was vigorously mixed overnight using a shaker, transferred to a Teflon liner, and the liner placed in a stainless-steel autoclave. The autoclave was transferred to an oven preheated to 135° C. and rotated at 40 rpm for 11 days. After 11 days, the autoclave was quenched with tap water. After doing so, the MCM-22(P) produced was recovered by repeating centrifugation and washing five times. The collected particles were calcined in a calcining furnace under an air flow of 200 mL/min at a heating rate of 1° C./min at 550° C. for 12 hours to produce MCM-22 particles.

Formation of MCM-22 seed layer
About 0.05 g of calcined MCM-22 particles were added to 40 mL of anhydrous toluene to produce a seed suspension. With this suspension sandwiched between coverslips, the α-Al ₂ O ₃ discs oriented vertically using a Teflon holder were sequentially placed in a dried glass reactor. After that, the glass reactor was sealed with parafilm and subjected to ultrasonic treatment (UC-10P, JEIO Tech, South Korea) for about 20 minutes. After sonication, the α-Al ₂ O ₃ discs were recovered and washed briefly with fresh toluene. The resulting MCM-22 seed layer was calcined at 450° C. for 12 hours with a heating rate of 0.5° C./min under an air flow of 200 mL/min. At this time, the manufactured MCM-22 seed layer is referred to as Layer M (Comparative Example 1).

Formation of heterogeneous films through secondary and tertiary growth
The MCM-22 seed layer was further subjected to a secondary hydrothermal synthetic growth. First, the molar composition of the final sol is 1-adamantylamine (1-adamantylamine, 97%, Sigma-Aldrich): ethylenediamine (99%, Sigma-Aldrich): fumed silica (CAB-O_Sil, M5): H A synthetic solution of 9:150:100:4000 ₂ O was prepared. The side coated with the MCM-22 seed layer was then placed on the Teflon liner with the Teflon holder facing downwards at an oblique angle. The synthesis solution was poured into a Teflon liner in a stainless-steel autoclave. The autoclave was transferred to an oven preheated to 160° C. and allowed to react for 1, 2, or 3 days and then quenched with tap water. The recovered MCM-22 seed layer was washed extensively with deionized water, and was heated at 550° C. for 12 hours at a heating rate of 0.5° C./min under an air flow of 200 mL/min in a furnace. Time calcined. At this time, the recovered α-Al ₂ O ₃ disk is indicated as MD_xd (Comparative Example 2-4), where M is the MCM-22 seed layer, D is the DDR zeolite, x is the hydrothermal reaction time ( 1 day, 2 days, or 3 days).

The calcined MD layers were intergrown using synthetic precursors that allow the synthesis of ZSM-58 (DDR-type zeolite). The calcined MD layer is placed in a synthesis precursor solution containing methyltropinium iodide (MTI) to proceed with hydrothermal synthesis to form a hydrothermal fluid with continuous out-of-plane orientation. DDR zeolite separation membranes of different polarities were grown in three dimensions. Specifically, both LUDOX HS-40 (40 wt% suspension in H ₂ O, Sigma-Aldrich) acting as a silica source and methyltropinium iodide were added to deionized water. The precursor solution thus prepared was mixed using a stirrer for about 1 hour. Further, after adding NaOH, the mixture was well mixed overnight using a stirrer. The molar composition of the synthetic precursor solution thus prepared is 100 _SiO2 :25 MTI:30 NaOH:4000 _H2O . After putting the alpha-alumina disk having the calcined MD layer into the precursor solution prepared in this way, it was placed in an oven preheated to 130° C. for varying times (5 days or 10 days). After hydrothermal synthesis, when the reaction was completed, it was quenched with tap water. The obtained separation membrane was immersed in deionized water and then dried overnight in an oven at 100°C. As a result, the product separation membrane is denoted as MDZ_xd (Comparative Example 5-6), where M is MCM-22, D is DDR, Z: ZSM-58, and x is for tertiary growth. time indicates the reaction time (days) of hydrothermal synthesis.

To control the defect structures, the fabricated separation membranes (MDZ_5d, MDZ_10d) were processed using Rapid Thermal Processing (RTP) as reported in the literature. Specifically, the prepared separation membrane was placed in a quartz tube under an argon gas flow of 200 mL/min, and a preheated furnace (nominal about 1000° C.) was rapidly moved toward the separation membrane. rice field. After 1 minute, the furnace was far from the separator. Both the RTP-treated separation membrane and the non-RTP-treated separation membrane were further calcined at 550° C. for 12 hours at a heating rate of 0.5° C./min under an air flow of 200 mL/min. The RTP treated MDZ separation membrane is denoted MDZ_xd_RC (Examples 1-2), where R in RC denotes rapid thermal processing and C denotes subsequent pre-existing calcination. Conversely, the separation membrane without RTP treatment is indicated as MDZ_xd_C (Comparative Example 7-8).

The MCM-22 seed layer was also subjected to secondary hydrothermal growth of MFI-type zeolite to evaluate its structural compatibility for DDR/MWW heteroepitaxial growth. The molar composition of the MFI zeolite synthesis sol is 40 SiO ₂ (tetraethyl orthosilicate, TEOS, Sigma-Aldrich): 9 tetrapropylammonium hydroxide (1.0 M in H ₂ O, Sigma-Aldrich): 9500 deionized water: 160 ethanol. The synthetic sol was poured into a Teflon-lined autoclave in which an MCM-22 seed layer was placed, as described above. The autoclave was placed in an oven preheated to 175° C. and the reaction was carried out for 1 day, 3 days and 5 days. The recovered MCM-22 seed layer was washed with deionized water and further calcined at 550° C. for 12 hours at a heating rate of 0.5° C./min under an air flow of 200 mL/min. For convenience, the layers obtained are designated MM_xd (Comparative Examples 9-11), where M and M denote MCM-22 and MFI zeolites, respectively, and x is the hydrothermal synthesis reaction time (1 day, respectively, 3 days or 5 days).

［実験例］
分離膜の特性
図４の（ａ）は、大きいａｂ－ｂａｓａｌ平面を有するディスク型ＭＣＭ－２２粒子が、超音波処理支援方法を使用して、多孔性支持体に均一に蒸着され、連続的で稠密なシード層を構成したことを示す。特に、支持体の表面と平行するａｂ平面を有するＭＣＭ－２２粒子の数が著しく増加すると、まず、平面外部方向（この場合、ｃ軸はメンブレン表面に垂直の方向に整列）に合成されることを示唆した。このｃ－面外方向（ｃ－ｏｕｔ ｏｆ ｐｌａｎｅ）は、図４の（ｆ）の当該Ｘ線回折法（ＸＲＤ）測定によって確認された。図４の（ｂ）をみると、ＤＤＲゼオライトの合成を許容する前駆体とともに、シード層の後続成長によって、ＤＤＲの粒子が若干成長した。これによって、ＭＣＭ－２２粒子の丸い形態は、六角形の隅を有する鋭い形態に変わり、このことは、ＭＷＷ型ゼオライトの単位細胞に沿って異種エピタキシャル成長（ｈｅｔｅｒｏｅｐｉｔａｘｉａｌ ｇｒｏｗｔｈ）したことを意味する。

[Experimental example]
Separation membrane characteristics
FIG. 4(a) Disk-shaped MCM-22 particles with large ab-basal planes were uniformly deposited on a porous support using a sonication-assisted method to form a continuous, dense seed layer. indicates that you have configured In particular, a significant increase in the number of MCM-22 particles with a-b planes parallel to the surface of the support is first synthesized in the planar out-of-plane direction (where the c-axis is aligned perpendicular to the membrane surface). suggested. This c-out of plane direction was confirmed by the relevant X-ray diffraction (XRD) measurements in FIG. 4(f). See FIG. 4(b), with the precursor allowing the synthesis of DDR zeolite, the subsequent growth of the seed layer resulted in some grain growth of DDR. Thereby, the round morphology of MCM-22 particles changed to sharp morphology with hexagonal corners, which means heteroepitaxial growth along the unit cell of MWW-type zeolite.

Although MWW and DDR zeolites have different crystal structures, the heteroepitaxial growth of DDR zeolite on the ab plane of MWW zeolite is apparently formed along the c-axis. Looking at FIG. 5, structural compatibility between the MWW and DDR type zeolites is formed along the c-axis, which appears to result in heteroepitaxial growth. Referring to FIG. 6, although the heterogeneous epitaxial growth looks good, the extent of the secondary growth is not clear, and the heterogeneous epitaxial growth is difficult. , confirmed that the sharp hexagonal morphology increases monotonically. However, due to the further growth of vertically grown plates from hexagonal planes in MD_xd with increased secondary growth time, 2 days hydrothermally synthesized MD_2d was selected as the optimal time to form MD layers. . The reason is that it is halfway between formed MD_1d and MD_3d. Also, looking at FIG. 7, no clear morphological changes were observed in the MD_2d layer, but the prolonged growth resulted in the growth of unwanted new crystals. These new crystals are known to grow competitively with DDR-type zeolite, and are highly likely to be SGT-type zeolite.

Referring to FIG. 8, the structural properties of the MD_2d layer were investigated, and the Le Bail structural analysis method was used to match the XRD pattern of the MD_2d layer based on the combination of MWW and DDR type zeolites. The results confirmed that the MD_2d layer was mainly composed of DDR type zeolite. However, the Le Bail structural analysis method could not explain the additional XRD peaks occurring on the SGT zeolites mentioned earlier. Also, the particles were separated from the MD_2d layer through sonication and analyzed by transmission electron microscopy (TEM). As a result, particles with sharp corners were clearly identified, as shown in FIG. 8(b). , confirming that it was grown from the MCM-22 deposition of the disk. FIG. 8(c) is a high-resolution transmission electron microscope (HR-TEM) image of the sharp corner region observed in FIG. 8(b); ), and the results are shown in FIG. 8(d). Along with the FFT pattern, an additional pattern was observed that occurred in the [001] domain axis of the MWW-type zeolite and might belong to the DDR-type zeolite (white arrow). This is provided by the simulated FFT patterns for the [001] domain axis of the MWW and DDR zeolites, as in the image inserted in FIG. 8(d).

In FIGS. 4b and 6, the hexagonal growth of disk-like MCM-22 deposits can be inferred from scanning electron microscope (SEM) images of the MD_2d layer, which corresponds to the DDR Zeolite growth was observed in the XRD pattern shown in FIG. 4(f), and transmission electron microscopy (TEM) analysis in FIG. 8(d) also showed heteroepitaxial growth (DDR/MWW ). 4(c) and 9(a-b), subsequent hydrothermal growth of the MD_2d layer using a precursor that allows the synthesis of ZSM-58 zeolite (DDR-type zeolite) clearly leads to MDZ_5d (Z indicates the ZSM-58 zeolite used for tertiary growth) leading to partially intergrown layers, FIGS. 4(de) and 9(cd). ) further led to a continuous separation membrane at MDZ_10d. However, it is easy to find the parts that were not intergrown in MDZ_5d, as indicated by the white arrows. Also, the proportion of ZSM-58 zeolites was evidenced by an increase in XRD peak intensity, as shown in FIGS. .

9 and 10, the morphology of the particles and crystal phases of the separation membrane (MDZ_10d_RC) subjected to the rapid thermal process (RTP) was indistinguishable from that of the slowly calcined Comparative Example 8 (MDZ_10d_C). . Interestingly, the intensity of the XRD peak corresponding to the (003) plane of MDZ_10D increased significantly, indicating the formation of some c-out-of-plane orientation. Figures 4f and 7 show that this c-out-of-plane direction was already present in the MD layer and increased in amount with increasing secondary growth time in the MCM-22 seed layer (layer_M). clearly shows that Looking at FIG. 6, such an out-of-plane c-plane orientation can be expected to occur in the disc-shaped MCM-22 grains that make up the MCM-22 seed layer and the growth into hexagonal plates with sharp corners. .

In FIG. 10, additional hydrothermal growth of the MD_2d layer from day 5 to day 10 favors growth in the c-out-of-plane direction while maintaining the c-out-of-plane direction in MD_2d. This directional growth indicates epitaxial growth from hexagonal plates in the presence of precursors that allow the synthesis of ZSM-58 zeolites. In particular, the crystallographic preferred orientation (CPO) index for MDZ_10d is estimated to be high, 7.6±3.9, thus showing clear alignment of the c-axis in the out-of-plane direction.

To confirm the heteroepitaxial growth, secondary growth was performed on the MCM-22 seed layer using a synthetic precursor that induces silicalite-1 (ie, MFI-type zeolite composed only of silica). gone. MFI zeolites are known to form easily in the presence of tetrapropylammonium (TPA) cations, but from FIG. It can be seen that there is difficulty in filling the gaps between the -22 particles. Through this, it can be seen that structural similarity or compatibility between the two types of zeolites is necessary to form a heterogeneous epitaxial growth-based separation membrane. FIG. 5 shows that the hexagonal ring structure (6-MR) of DDR-type zeolite is located in the plane perpendicular to the c-axis in the heterogeneous separation membrane of MDZ_10d. Thus, preferentially, the c-out-of-plane oriented heteroseparation membrane (ie, MDZ_10d) possessed a significant number of 6-MR pores in the out-of-plane direction. This makes the separation membrane a good platform that can be used to assess the molecular capacity of 6-MR pores to separate H ₂ from CO ₂ .

Separation Performance of Gas Separation Membranes As expected from the discontinuities observed by scanning electron microscopy (SEM) shown in FIGS. Neither showed molecular body ability. Although rapid thermal processing (RTP) was helpful, the degree of intergrowth of MDZ_5d, which achieved a slight increase in separation performance, was not sufficient to ensure molecular body capacity. (a1, b1, c1) of FIG. 13 show that the existing calcined MDZ_10d_C is inferior to all three sets of gases (H ₂ /CO ₂ , CO ₂ /N ₂ , CO ₂ /CH ₄ ). Separation performance is shown, which indicates the existence of clear defects. In Fig. 9(d), MDZ_10d_C exhibits very poor permselectivity despite the apparent film continuity at scanning electron microscope (SEM) resolution, which is due to the calcination method of the synthesized film or layer. Show importance. In contrast, the separation membranes that underwent rapid thermal processing (RTP) (i.e., MDZ_10d_RC) showed significantly improved permselectivity to _CO2 , especially in all three cases, indicating that RTP was associated with a reduced degree of defects. indicates that it has contributed to Also, although the 6-MR pores of MDZ_10d_RC are expected to contribute significantly to _H2 permeation, the corresponding _H2 / _CO2 separation factor (SF) at 30 °C is about 0.37 ( 1) and about 0.97 at 125°C. Also, the maximum H ₂ /CO ₂ SF at 200° C. was still very low, about 1.7. This means that the 6-MR pore diameter (maximum size 0.28 nm) was not adapted for maximum H ₂ /CO _{2 -} separation. Since the structural properties of MDZ_10d_RC are similar to those of similar DDR separation membranes, the H ₂ /CO ₂ , CO ₂ /N ₂ , CO ₂ /CH ₄ separation performance of MDZ_10d_RC is similar to that of DDR separation membranes. Performance was similar, but showed much lower _CO2 permeance over MDZ_10d_RC. For better comparison, looking at the middle and right columns of FIG. 13, both the H ₂ /CO ₂ , CO ₂ /N ₂ and CO ₂ /CH ₄ separation performances of MDZ_10d_RC and similar DDR separation membranes are shown. . Clearly, the CO ₂ permeability of MDZ_10d_RC decreased to a similar level when compared to a similar DDR separation membrane with more 8-MR channels oriented perpendicular to the membrane surface. Therefore, it can be inferred that the 6-MR pore of DDR zeolites is not suitable for H ₂ /CO ₂ separation, whereas the 6-MR pore of other types of zeolites (not sodalite) can be used for H The molecular filtering ability for ₂ /CO ₂ separation must be confirmed. In particular, H ₂ /CO ₂ separation under harsh conditions (high pressure and high temperature) is important in realizing a water-gas shift separation membrane reactor, so it can play a role as a wall in the construction of a separation membrane reactor. Experiments through zeolite membranes are essential. The above separation performance results indicate that it is reasonable to post-treat zeolites with 8-MR or 10-MR to achieve superior H ₂ /CO ₂ separation performance through pore size reduction of the substrate. Conceivable. In the actual literature, MFI zeolite separation membranes with reduced pore size are also used in separation membrane reactors to achieve significant _H2 recovery and _CO2 conversion with high _H2 / _CO2 separation factor through the separation membrane reactors. I was able to get Also, looking at a1-a2 in FIG. 14, the addition of water vapor to the binary mixture feed increases the permeation of H ₂ and CO ₂ at temperatures below 100° C., the temperature at which the degree of moisture adsorption of DDR zeolites is assured. degree decreased. In contrast, the permeabilities of _H2 and _CO2 were unchanged by the presence of water vapor at temperatures above 100°C. Interestingly, the degree of transmittance decrease was similar up to 200°C for both _H2 and _CO2 . Therefore, the H ₂ /CO ₂ separation factor under the wet condition of a2 in FIG. 14 was similar to the H ₂ /CO ₂ separation factor under the dry condition of a1 in FIG. 14 . Also, looking at b1-b2 in FIG. 14, water vapor in the feed increased the CO ₂ /N ₂ separation factor (SF) while decreasing the CO ₂ permeability, especially below 100°C. In contrast, looking at c1,c2 in FIG. 14, the reduced permeance is higher for _CO2 than for _CH4 in the _CO2 / _CH4 separation, thereby resulting in the _CO2 / _CH4 separation The modulus (SF) was reduced to about 50°C under damp conditions. In particular, the CO ₂ /N ₂ and CO ₂ /CH ₄ separation trends induced by water vapor were very similar to those of reported homogeneous DDR separation membranes. The main difference is the lower CO ₂ permeability in the previously mentioned MDZ_10d_RC, which occurs in a substantial fraction of DDR zeolites with a distinct c-out-of-plane orientation. Referring to FIG. 15, the higher _CO2 / _N2 separation factor (SF) under wet conditions is attributed to the hydrophobicity of the siliceous DDR zeolite in MDZ_10d_RC (see inset image of FIG. 4(e)). obtain. In contrast, the contact angle measurement of MDZ_10d_C confirmed that the droplets disappeared quickly, confirming that MDZ_10d_C had many defects.

Figure 16 is a fluorescence confocal optical microscope (FCOM) image of MDZ_10d_C and _{MDZ_10d_RC} . I understand. Thereby, the corresponding defect levels can be seen as high for MDZ_10d_C and low for MDZ_10d_RC. Since the contribution of defects, particularly cracks, to the actual measured transmittance is a coupled function of defect size (width) and number (density), such factors are considered together to estimate the final apparent performance. must understand. Also, staining the separation membrane for various periods of time provides additional information on the defect structure. The defects (mainly cracks) of MDZ_10d_C were progressively invaded by dye molecules as the staining time increased. In particular, some cracks reaching the interface between the zeolite membrane and the porous support were visible only after 12 hours of dye contact (indicated by yellow arrows in a2 of FIG. 16). Conversely, looking at c2 and d2 in Fig. 16, MDZ_10d_RC had a high density or a high number of cracks, as indicated by the yellow dotted line in c2 of Fig. 16, but they did not propagate completely to the interface. There was no. Looking at Figure 16 a3, b3, we visualized more cracks propagating to the interface through long-term staining of MDZ_10d_C (24 h). In contrast, the number of cracks in MDZ_10d_RC detected after 12 hours of staining remained the same, with more dye molecules able to access regions closer to the interface, but only up to the middle part of the separation membrane ( (indicated by the yellow dotted line in c3 of FIG. 16). Finally, after 60 hours of staining, additional cracks in MDZ_10d_C propagated to the interface were observed, with a greater number or density of cracks present in MDZ_10d_RC being fully approached by dye molecules.

17 and 18, it was confirmed that the number and size of cracks in MDZ_10d_C were smaller and larger than the number and size of cracks in MDZ_10d_RC through the dyeing process with different times. Image processing of the fluorescence confocal light microscopy images provided additional confirmation for the number of defects. Referring to Table 2, the pixel-based area fraction is 0.020 for MDZ_10d_C and 0.035 for MDZ_10d_RC. After the image processing process was completed, crack features were well reconstructed, as shown in FIG. Despite the difference in crack density, the crack strain due to the thickness of the separation membrane is about 1.6 for both MDZ_10d_C and MDZ_10d_RC, as shown in Table 2, which means that the molecules permeating the separation membrane are equally distributed. It means that you should follow a slightly sloping path. Looking at FIG. 20, the cracking characteristics of MDZ_10d_C were similar to those of similar DDR separators, but MDZ_10d_RC had a higher number of cracks. Considering that similar DDR separation membranes exhibited high _CO2 permselectivity, the size of the cracks in MDZ_10d_C was clearly too large to ensure molecular body capacity. At present, rapid thermal processing (RTP) is known to condense particles in polycrystalline zeolite separation membranes and effectively reduce the size of defects. It shows that the stress generated upon removal of the structure directing agent (SDA) can be reduced while generating a greater number of small cracks when the process (RTP) is performed. In summary, MDZ_10d_RC, which had a higher number of defects but showed better isolation performance than MDZ_10d_C, shows that shrinking the defect size is a more important factor to ensure superior isolation performance.

Claims (16)

comprising one or more MWW-type zeolites and one or more DDR-type zeolites;
The MWW-type zeolite and the DDR-type zeolite are provided alternately, and at least one of the MWW-type zeolite and the DDR-type zeolite has an epitaxial structure . /DDR type gas separation membrane. 2. The gas separation membrane of claim 1, wherein the MWW-type zeolite and the DDR-type zeolite independently form layers and are alternately provided. 2. The gas separation membrane according to claim 1, wherein the MWW-type zeolite has a standard Si:Al molar ratio of 100:0-10. 2. The gas separation membrane according to claim 1, wherein the DDR type zeolite has a standard Si:Al molar ratio of 100:0-10. When the DDR type zeolite is provided on the MWW type zeolite in the first direction, the MWW type zeolite is composed of a group of a plurality of MWW type zeolite particles, and the MWW type zeolite particles are arranged in the first direction. has an average length of 10 nm to 1 μm parallel to
When the MWW-type zeolite is provided on the DDR-type zeolite in the first direction, the DDR-type zeolite is composed of a group of a plurality of DDR-type zeolite particles, and the DDR-type zeolite particles are arranged in the first direction. The gas separation membrane according to claim 1 , comprising one having an average length parallel to 0.1 μm to 10 μm. 2. The gas separation membrane of claim 1, wherein the gas separation membrane separates carbon dioxide gas ( _CO2 ) from a gas mixture. A plurality of first zeolite particles produced by a hydrothermal synthesis method using a first zeolite precursor solution containing a first structure-inducing agent and a first raw material are provided on a support to form an MWW-type zeolite. a step of forming a MWW-type zeolite; and growing a DDR-type zeolite on said MWW-type zeolite by hydrothermal synthesis using a second zeolite precursor solution containing a second structure directing agent and a second raw material. a zeolite forming step;
The first or second raw material contains at least one or more of Si and Al, respectively,
A method for producing a gas separation membrane, wherein the MWW-type zeolite is provided on the support in the form of a plurality of particles, and the DDR-type zeolite is epitaxially grown on the MWW-type zeolite. The MWW-type zeolite has an average particle length of 10 nm to 1 μm,
The molar concentration ratio of the first zeolite precursor solution is Si:Al:structure inducer:solvent=100:0-10:10-500:500-20000,
8. The gas separation membrane according to claim 7 , wherein the molar concentration ratio of the second zeolite precursor solution is Si:Al:structure inducer:solvent=100:0-10:1-200:500-20000. Production method. The MWW-type zeolite has an average particle length of 0.1 μm to 10 μm,
The molar concentration ratio of the first zeolite precursor solution is Si:Al:structure inducer:solvent=100:0 to 10:1 to 200:500 to 20000,
8. The gas separation membrane according to claim 7 , wherein the molar concentration ratio of the second zeolite precursor solution is Si:Al:structure inducer:solvent=100:0-10:10-500:500-20000. Production method. The first and second structure directing agents are independently hexamethyleneimine (HMI), piperidine, adamantylamine (1-adamantylamine), ethylenediamine, methyltropinium salts, 1-TMAdaOH (N,N,N-trimethyl-1-adamantylammonium hydroxide), TMAdaBr (N,N,N-trimethyl-1-adamantylammonium bromide), TMAdaF (N,N,N-trimethyl-1-adamantyl), ＴＭＡｄａＣｌ（Ｎ，Ｎ，Ｎ－ｔｒｉｍｅｔｈｙｌ－１－ａｄａｍａｎｔｙｌａｍｍｏｎｉｕｍ ｃｈｌｏｒｉｄｅ）、ＴＭＡｄａＩ（Ｎ，Ｎ，Ｎ－ｔｒｉｍｅｔｈｙｌ－１－ａｄａｍａｎｔｙｌａｍｍｏｎｉｕｍ ｉｏｄｉｄｅ）、ＴＥＡＯＨ（ｔｅｔｒａｅｔｈｙｌａｍｍｏｎｉｕｍ ｈｙｄｒｏｘｉｄｅ）、ＴＥＡＢｒ（ｔｅｔｒａｅｔｈｙｌａｍｍｏｎｉｕｍ ｂｒｏｍｉｄｅ）、ＴＥＡＦ（ｔｅｔｒａｅｔｈｙｌａｍｍｏｎｉｕｍ ｆｌｕｏｒｉｄｅ）、 8. The method for producing a gas separation membrane according to claim 7 , wherein at least one of TEACl (tetraethylammonium chloride), TEAI (tetraethylammonium iodide), dipropylamine, and cyclohexylamine is used. The support includes α-alumina, γ-alumina, polypropylene, polyethylene, polytetrafluoroethylene, polysulfone, polyimide, silica, glass, mullite, zirconia, titania, yttria. , ceria, vanadia, silicon, stainless steel , carbon, calcium oxide, and phosphorous oxide. Between the MWW-type zeolite forming step and the DDR-type zeolite forming step,
further comprising a buffer portion forming step of forming a buffer portion covering at least a portion of the plurality of first zeolite particles in the MWW-type zeolite forming step;
The buffer part forming step is performed using a buffer part precursor solution in which adamantylamine:ethylenediamine:fumed silica:solvent is mixed at a molar concentration of 1-20:100-200:100:1000-20000. 8. The method for producing a gas separation membrane according to claim 7 , wherein a buffer portion is provided on the MWW-type zeolite by a hydrothermal synthesis method. In the buffer portion forming step,
13. The gas of claim 12 , wherein the MWW-type and DDR-type zeolites are different types of zeolites, and the zeolite structure formed by the buffer part precursor solution is the same as the DDR-type zeolite structure. A method for producing a separation membrane. The MWW-type zeolite formation step and the DDR-type zeolite formation step are independently performed at a temperature of 450 to 550° C. at a rate of 0.2 to 0.5° C./min for 12 to 40 hours after hydrothermal synthesis. 8. The method for producing a gas separation membrane according to claim 7 , further comprising the step of heating and calcining at. The method for producing a gas separation membrane according to claim 7 , further comprising a step of rapid heat treatment at a temperature of 700 to 1200°C for 10 seconds to 5 minutes after the DDR type zeolite formation step. The DDR-type zeolite forming step of growing DDR-type zeolite on the MWW-type zeolite by the hydrothermal synthesis method comprises hydrothermal synthesis at a temperature of 100° C. to 200° C. for 0.5 days to 15 days. Item 8. A method for producing a gas separation membrane according to Item 7.

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