JP2016190200A - Manufacturing method for zeolite film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method for a zeolite film capable of improving separability and penetrability.SOLUTION: A manufacturing method for a zeolite film 30 comprises steps of: coating a support 20 with first seeding slurry containing a first zeolite seed crystal 31a; growing the first zeolite seed crystal 31a to form a first zeolite crystal 31; coating the support 20 where the first zeolite crystal 31 is formed with second seeding slurry containing a second zeolite seed crystal 32a; and growing the second zeolite seed crystal 32a to form a second zeolite crystal 32.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a method for producing a zeolite membrane.

  Conventionally, a method of forming a zeolite membrane on the surface of a support using a zeolite seed crystal (hereinafter referred to as “seed crystal”) is known (for example, see Patent Document 1). The seed crystal applied on the surface of the support grows into a film to form a zeolite membrane.

JP 2003-159518 A

  Here, the separability of the zeolite membrane improves as the number of membrane defects decreases, and the permeability of the zeolite membrane tends to improve as the film thickness decreases. However, if crystal growth is performed for a long time in order to reduce film defects, the film thickness becomes thick, and it is not easy to achieve both separation and permeability.

  This invention is made | formed in view of the above-mentioned situation, and it aims at providing the manufacturing method of the zeolite membrane which can improve the separability and permeability | transmittance of a zeolite membrane.

  The method for producing a zeolite membrane structure according to the present invention includes a step of applying a first seeding slurry containing a first zeolite seed crystal to a support, and growing the first zeolite seed crystal to form a first zeolite crystal. Forming a second zeolite crystal by growing the second zeolite seed crystal, applying the second seeding slurry containing the second zeolite seed crystal to the support on which the first zeolite crystal is formed, and forming the second zeolite crystal. And a step of performing.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the zeolite membrane which can improve separability and permeability | transmittance can be provided.

Cross section of zeolite membrane structure Schematic diagram for explaining a method for producing a zeolite membrane

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, the drawings are schematic, and the ratio of each dimension may be different from the actual one. Accordingly, specific dimensions and the like should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

(Configuration of separation membrane structure 10)
FIG. 1 is a cross-sectional view showing the configuration of the separation membrane structure 10. The separation membrane structure 10 includes a support 20 and a zeolite membrane 30.

  The support 20 supports the zeolite membrane 30. The support 20 has chemical stability such that the zeolite membrane 30 can be formed into a film shape (crystallization, coating, or deposition) on the surface. The support 20 may have any shape that can supply a mixed fluid to be separated to the zeolite membrane 30. Examples of the shape of the support 20 include a honeycomb shape, a monolith shape, a flat plate shape, a tubular shape, a cylindrical shape, a columnar shape, and a prismatic shape. In the present embodiment, the support 20 has a base body 21, an intermediate layer 22, and a surface layer 23.

  The base 21 is made of a porous material. As the porous material, for example, a ceramic sintered body, metal, organic polymer, glass, or carbon can be used. Examples of the ceramic sintered body include alumina, silica, mullite, zirconia, titania, yttria, silicon nitride, and silicon carbide. Examples of the metal include aluminum, iron, bronze, silver, and stainless steel. Examples of the organic polymer include polyethylene, polypropylene, polytetrafluoroethylene, polysulfone, and polyimide.

  The base 21 may contain an inorganic binder. As the inorganic binder, at least one of titania, mullite, easily sinterable alumina, silica, glass frit, clay mineral, and easily sinterable cordierite can be used.

  The average pore diameter of the substrate 21 can be set to, for example, 5 μm to 25 μm. The average pore diameter of the substrate 21 can be measured with a mercury porosimeter. The porosity of the substrate 21 can be set to, for example, 25% to 50%. The average particle diameter of the porous material constituting the substrate 21 can be set to 5 μm to 100 μm, for example. The average particle diameter of the substrate 21 is a value obtained by arithmetically averaging the maximum diameters of 30 measurement target particles measured by cross-sectional microstructure observation using a SEM (scanning electron microscope).

  The intermediate layer 22 is formed on the base 21. The intermediate layer 22 can be made of the porous material that can be used for the substrate 21. The average pore diameter of the intermediate layer 22 may be smaller than the average pore diameter of the substrate 21, and may be, for example, 0.005 μm to 2 μm. The average pore diameter of the intermediate layer 22 can be measured with a palm porometer. The porosity of the intermediate layer 22 can be set to, for example, 20% to 60%. The thickness of the intermediate layer 22 can be set to 30 μm to 300 μm, for example.

  The surface layer 23 is formed on the intermediate layer 22. The surface layer 23 can be composed of the porous material that can be used for the base 21. The average pore diameter of the surface layer 23 may be smaller than the average pore diameter of the intermediate layer 22, and may be, for example, 0.001 μm to 0.5 μm. The average pore diameter of the surface layer 23 can be measured with a palm porometer. The porosity of the surface layer 23 can be set to, for example, 20% to 60%. The thickness of the surface layer 23 can be set to 1 μm to 50 μm, for example.

  The zeolite membrane 30 is formed on the surface of the support 20. When the support 20 is formed in a monolith shape, the zeolite membrane 30 is formed on the inner walls of a plurality of through holes formed in the support 20.

  The skeleton structure (type) of the zeolite contained in the zeolite membrane 30 as a main component is not particularly limited. For example, MFI, LTA, CHA, DDR, MOR, DOH, FAU, OFF / ERI, LTL, FER, BEA, BEC, CON, MSE, MEL, MTW, MEI, MWW, RHO, BOG, SZR, EMT, SOD, AEI, AEL, AEN, AET, AFN, AFO, AFR, AFS, AFT, AFI, AFX, ANA, CAN, GIS, GME, HEU, JBW, KFI, LAU, LEV, MAZ, MER, MFS, MTT, PHI, SFG, TUN, TON, UFI, VET, VFI, VNI, VSV and the like. In particular, MFI, DDR, MEL, BEA, CHA, MOR, FAU, LTA, FER, and SOD are preferred, and MFI, DDR, MEL, BEA, and CHA, which have high chemical stability, are particularly preferred. In the present embodiment, the composition X “contains the substance Y as a main component” means that the substance Y preferably accounts for 60% by weight or more, more preferably 70% by weight or more in the entire composition X. Means more preferably 90% by weight or more.

  The zeolite membrane 30 may contain an inorganic binder (such as silica or alumina), an organic binder (such as a polymer), and a silylating agent.

  The Si / Al atomic ratio of the zeolite membrane 30 is not particularly limited, but can be, for example, 1.5 or more. The zeolite membrane 30 may be composed of high silica zeolite having an Si / Al atomic ratio of 200 or more. The Si / Al atomic ratio of the zeolite membrane 30 can be adjusted by controlling the reaction solution and reaction conditions used for hydrothermal synthesis. The Si / Al atomic ratio of the zeolite membrane 30 can be measured by SEM-EDX (scanning electron microscope-energy dispersive X-ray spectroscopy).

  The thickness of the zeolite membrane 30 is not particularly limited, but can be, for example, 0.1 μm to 10 μm. The permeability can be improved as the thickness of the zeolite membrane 30 is reduced.

  The average pore diameter of the zeolite membrane 30 is not particularly limited and can be adjusted according to the liquid mixture to be separated. The average pore diameter of the zeolite membrane 30 can be adjusted, for example, by specifying the framework structure of the zeolite by changing the type and size of the structure-directing agent or template. The average pore diameter of the zeolite membrane 30 can be set to 0.2 nm to 2.0 nm, for example. However, the average pore diameter of the zeolite membrane 30 may have a major axis and a minor axis. For example, the minor axis of the pores of the DDR type zeolite membrane is 0.36 nm and the major axis is 0.44 nm.

(Method for producing separation membrane structure)
A method for manufacturing the separation membrane structure 10 will be described. FIG. 2 is a schematic diagram for explaining a method of manufacturing the separation membrane structure 10.

  First, a molded body of the base 21 having a desired shape is formed by an extrusion molding method, a press molding method, a casting molding method, or the like. Next, the molded body of the base body 21 is fired (for example, 900 ° C. to 1450 ° C.) to form the base body 21.

  Next, the intermediate layer 22 is formed by forming a slurry for the intermediate layer prepared using a ceramic raw material having a desired particle diameter on the surface of the substrate 21. Next, the intermediate layer 22 is formed by firing the molded body of the intermediate layer 22 (for example, 900 ° C. to 1450 ° C.).

  Next, the surface layer 23 is formed on the surface of the intermediate layer 22 by forming a slurry for the surface layer using a ceramic raw material having a desired particle diameter, thereby forming a formed body of the surface layer 23. Next, the molded body of the surface layer 23 is fired (for example, 900 ° C. to 1450 ° C.) to form the surface layer 23.

  Next, the 1st zeolite seed crystal 31a is produced using a conventional method. For example, when a CHA type zeolite membrane is formed as the zeolite membrane 30, M.I. Itakura et al. , Chemistry Letters vol. 37, no. 9 (2008) 908, the FAU-type zeolite structure conversion method can be used. In the case of forming a DDR type zeolite membrane as the zeolite membrane 30, the technique described in Japanese Patent Application Laid-Open No. 2004-83375 can be used.

  Next, a first seeding slurry containing the first zeolite seed crystal 31a is prepared by dispersing the first zeolite seed crystal 31a in water or alcohol. The framework structure of the first zeolite seed crystal 31a may be selected according to the framework structure of the zeolite membrane 30. The average particle size of the first zeolite seed crystal 31a is not particularly limited, but can be, for example, 100 nm to 300 nm.

  Here, in the present embodiment, the “average particle diameter of the seed crystal” is a median value of the particle diameter on a volume basis, and can be measured by a dynamic light scattering method. Specifically, the particle size distribution of a suspension obtained by dropping a dispersion of seed crystals in water into water so as to have a measurable concentration and then dispersing with ultrasonic waves is the dynamic light scattering particle size. Measure with a distribution measuring device. The median diameter (D50) obtained from the measured particle size distribution is the average particle diameter of the seed crystal.

Next, after applying the first seeding slurry to the support 20 by a flow-down method, a dip method, or the like, the first seeding slurry is blown and dried. Thereby, as shown in FIG. 2A, the first zeolite seed crystal 31 a adheres to the surface of the support 20. The coating amount of the first zeolite seed crystal 31a per unit area is not particularly limited, but may be, for example, 0.005 g / m ^{2 to} 1.0 g / m ² .

  Next, the support 20 is immersed in a pressure resistant container containing a raw material solution containing a silica source, an alumina source, an alkali source, and water. The raw material solution may contain an organic template.

  Next, the pressure vessel is placed in a dryer and heated (hydrothermal synthesis). Thereby, as shown in FIG. 2B, the first zeolite seed crystal 31a grows and the first zeolite crystal 31 is formed. In the present embodiment, it is assumed that a film defect (gap) exists in the first zeolite crystal 31 as shown in FIG. The heating temperature can be 100 to 200 ° C. The heating time can be 3 to 40 hours, preferably 5 hours or more.

  Next, the support 20 on which the first zeolite crystals 31 are formed is washed and dried at 80 to 100 ° C.

  Next, a second seeding slurry containing the second zeolite seed crystal 32a is prepared by dispersing the second zeolite seed crystal 32a in water, alcohol, or the like. The framework structure of the second zeolite seed crystal 32a is preferably the same as that of the first zeolite seed crystal 31a. The average particle diameter of the second zeolite seed crystal 32a is not particularly limited, but may be, for example, 80 nm to 280 nm. The average particle size of the second zeolite seed crystal 32a is preferably smaller than the average particle size of the first zeolite seed crystal 31a.

Next, the second seeding slurry is applied to the first zeolite crystal 31 by a flow-down method or a dip method, and then the second seeding slurry is blown and dried. As a result, as shown in FIG. 2C, the second zeolite seed crystal 32 a enters the gap between the first zeolite crystals 31. The second zeolite seed crystal 32a is more likely to enter the gap between the first zeolite crystals 31 as the average particle size is smaller. The coating amount of the second zeolite seed crystal 32a per unit area is not particularly limited and may be, for example ^{0.002g / m 2 ~0.8g / m 2} . The coating amount of the second zeolite seed crystal 32a per unit area is preferably smaller than the coating amount of the first zeolite seed crystal 31a per unit area.

  Next, by putting the pressure vessel in a dryer and heating (hydrothermal synthesis), as shown in FIG. 2 (d), the second zeolite seed crystal 32a grows and the second zeolite crystal 32 is formed. The At this time, the first zeolite crystal 31 continues to grow. In FIG. 2 (d), the first zeolite crystal 31 and the second zeolite crystal 32 are drawn separately, but both constitute a zeolite membrane 30 together. Thereby, since the membrane defect of the first zeolite crystal 31 can be filled with the second zeolite crystal 32 in a short time, the separability and permeability of the zeolite membrane 30 can be improved. The heating temperature can be 100 to 200 ° C. The heating time can be 2 hours to 35 hours, preferably 30 hours or less. In particular, since the entire thickness of the zeolite membrane 30 can be reduced by shortening the time for forming the second zeolite crystal 32 than the time for forming the first zeolite crystal 31, the permeability of the zeolite membrane 30 can be further improved. it can.

  Next, the support 20 on which the zeolite membrane 30 is formed is washed and dried at 80 to 100 ° C.

  Next, when the organic template is contained in the raw material solution, the support 20 is put in an electric furnace and heated in the atmosphere (400 to 800 ° C. for 1 to 200 hours) to burn and remove the organic template. .

(Feature)
The manufacturing method of the zeolite membrane 30 according to the present embodiment includes a step of applying a second seeding slurry containing the second zeolite seed crystal 32a to the first zeolite crystal 31, and growing the second zeolite seed crystal 32a. Forming a second zeolite crystal 32.

  Thus, since the second zeolite crystal 32 is formed by the crystal growth of the second zeolite seed crystal 32a that has entered the gap between the first zeolite crystals 31, the dense zeolite film 30 can be formed in a short time. Therefore, both the separability and the permeability can be improved by making the zeolite membrane 30 thin and dense.

(Other embodiments)
In the above-described embodiment, the second seeding slurry is applied to the first zeolite crystal 31. From the base side of the support 20 while supplying the applied second seeding slurry to the first zeolite crystal side. You may suck with a pump. Thereby, the second zeolite seed crystal 32 a can be positively filled in the gaps between the first zeolite crystals 31.

  In the above embodiment, the second seeding slurry is applied to the first zeolite crystal 31, but the applied second seeding slurry may be washed away. As a result, the second zeolite seed crystal 32a that has entered the gap between the first zeolite crystals 31 can remain, and the excess second zeolite seed crystal 32a attached to the surface of the first zeolite crystal 31 can be removed. Can be made thinner.

  In the above embodiment, the support 20 has the base 21, the intermediate layer 22, and the surface layer 23. However, the support 20 may not have one or both of the intermediate layer 22 and the surface layer 23.

  In the above embodiment, the separation membrane structure 10 includes the support 20 and the zeolite membrane 30, but may further include a functional membrane or a protective membrane laminated on the zeolite membrane 30. As such a film, an inorganic film such as a zeolite film, a carbon film, or a silica film, or an organic film such as a polyimide film or a silicone film can be used.

  Examples of the present invention will be described below. However, the present invention is not limited to the examples described below.

(Production of sample Nos. 1 to 12)
First, a porous support (diameter 30 mm × length 160 mm, average pore diameter 0.10 μm) on which 55 cells were formed was prepared.

  Next, water and an organic binder were mixed with the glass frit to prepare a slurry for glass sealing.

  Next, a glass seal slurry was adhered to both end faces of the support, followed by drying to form a pair of glass seal compacts.

  Next, a pair of glass seals were formed by firing a pair of glass seal compacts at 950 ° C.

  Next, after putting ethylenediamine (manufactured by Wako Pure Chemical Industries, Ltd.) into a sealed container made of fluororesin, 1-adamantanamine (manufactured by Sigma Aldrich) is added, and 1-adamantanamine is completely dissolved by ultrasound. It was.

  Next, an aqueous solution containing DDR type zeolite crystals as nuclei was placed in another container, and silica sol containing silica (Snowtex S, manufactured by Nissan Chemical Industries, Ltd.) was added and stirred to obtain a silica sol containing nuclei. . A DDR type zeolite crystal as a core was obtained by pulverizing a DDR type zeolite powder produced based on the method described in WO2010 / 090049A1.

  Next, after rapidly adding the silica sol containing the nucleus prepared previously to the sealed container containing ethylenediamine in which 1-adamantanamine is dissolved, the mixture solution in the sealed container is stirred until it becomes transparent, thereby starting the raw material solution ( A raw material sol) was obtained.

  Next, the raw material solution was put into a stainless steel pressure vessel with a fluororesin inner cylinder, and heated (hydrothermal synthesis) at 160 ° C. for 16 hours.

  Next, a first DDR type zeolite seed crystal (hereinafter referred to as “first zeolite seed crystal”) was dispersed by washing with water.

  Next, a first seeding slurry was prepared by dropping and stirring the first zeolite seed crystal dispersion in ethanol.

  Next, the first seeding slurry was poured into 55 cells of the support from above the vertically placed support. As a result, the first seeding slurry was applied to the cell wall surface.

  Next, the first seeding slurry applied to the cell wall surface was dried by flowing air at room temperature at a wind speed of 5 m / second for 10 minutes through the cell. The coating amount of the first zeolite seed crystal per unit area of the cell wall surface was as shown in Table 1. The coating amount of the first zeolite seed crystals was adjusted by controlling the concentration of the first zeolite seed crystals in the first seeding slurry.

  Next, after putting ethylenediamine (manufactured by Wako Pure Chemical Industries, Ltd.) into a fluororesin container, 1-adamantanamine (manufactured by Sigma Aldrich) was added and completely dissolved.

  Next, after putting silica sol (Snowtex S, manufactured by Nissan Chemical Industries, Ltd.) containing silica and ion-exchanged water in another container, a silica dispersion was prepared by gently stirring.

  Next, an ethylenediamine solution in which 1-adamantanamine was dissolved was added to the silica dispersion and stirred for 90 minutes to prepare a film forming raw material solution.

  Next, the support body which the 1st zeolite seed crystal adhered in the stainless steel pressure-resistant container with a fluororesin inner cylinder was arrange | positioned.

  Next, the film-forming raw material solution is put in a container and heated (hydrothermal synthesis) at 125 ° C. to thereby form a first DDR type zeolite crystal containing 1-adamantanamine (hereinafter referred to as “first zeolite crystal”). ) Was formed. The hydrothermal synthesis time was as shown in Table 1.

  Next, the support taken out from the container was washed in water and then dried.

  Next, a second seed crystal dispersion in which a second DDR type zeolite seed crystal (hereinafter referred to as “second zeolite seed crystal”) was dispersed in water was prepared in the same manner as the first seed crystal dispersion described above. . By adjusting the temperature and time of hydrothermal synthesis, the average particle size of the second zeolite seed crystals was changed as shown in Table 1.

  Next, a second seeding slurry containing a second zeolite seed crystal was prepared in the same manner as the first seeding slurry described above.

  Next, the second seeding slurry was poured into each cell of the support, and the second seeding slurry was applied to the surface of the first zeolite crystals. The coating amount of the second zeolite seed crystal per unit area of the cell wall surface was as shown in Table 1. The coating amount of the second zeolite seed crystal was adjusted by controlling the concentration of the second zeolite seed crystal in the second seeding slurry.

  Next, the support body to which the second zeolite seed crystal was attached was placed in a stainless steel pressure resistant vessel with a fluororesin inner cylinder.

  Next, the above-mentioned raw material solution for film formation is put in a container and heated at 125 ° C. (hydrothermal synthesis) to thereby produce a second DDR type zeolite crystal containing 1-adamantanamine (hereinafter referred to as “second zeolite crystal”). Formed). The hydrothermal synthesis time was as shown in Table 1. Thus, a DDR type zeolite membrane (hereinafter referred to as “zeolite membrane”) composed of the first and second zeolite crystals was formed.

  Next, the support taken out from the container was washed in water and then dried.

  Next, the 1-adamantanamine was burned off by heating the zeolite membrane at 450 ° C. for 100 hours.

(Production of sample Nos. 13 to 15)
Sample No. 2 except that no second zeolite crystals were formed. Sample No. 1 in the same manner as in Nos. 1-12. 13-15 were produced. Therefore, sample no. In 13 to 15, the zeolite membrane is composed only of the first zeolite crystals.

  Sample No. In No. 15, the first zeolite seed crystal (zeolite membrane) was formed by hydrothermal synthesis of the first zeolite seed crystal in two portions.

(Measurement of average particle size of first and second zeolite seed crystals)
The first seed crystal dispersion liquid of each sample was dropped into about 20 ml of water so as to have a measurable concentration, and then dispersed with an ultrasonic wave for 5 minutes or more to obtain a suspension of the first zeolite seed crystal.

  Next, the particle size distribution of the suspension was measured with a dynamic light scattering type particle size distribution measuring device (trade name: Nanotrac, manufactured by Nikkiso Co., Ltd.), and the median diameter (D50) of the particle size distribution was obtained as the average particle size.

  The average particle size of the second zeolite seed crystal was also measured by the same method.

  The average particle size of each of the first and second zeolite seed crystals of each sample was as shown in Table 1.

(Measurement of N ₂ permeation amount of support)
Before the application of the first seeding slurry, the N ₂ gas permeation amount (hereinafter referred to as “support N ₂ permeation amount”) in each sample was measured. Specifically, N ₂ gas of 0.8 KPa was introduced into the cell of the support, and the amount of support N ₂ permeating through the support was measured with a mass flow meter. The measurement results are as shown in Table 1.

(Measurement of N ₂ permeation amount of support on which first zeolite crystals are formed)
After the formation of the first zeolite crystals, the permeation amount of N ₂ gas in each sample (hereinafter referred to as “first N ₂ permeation amount”) was measured. Specifically, N ₂ gas of 100 KPa was introduced into the cell of the support, and the first N ₂ permeation amount permeated through the support on which the first zeolite crystals were formed was measured with a mass flow meter. The measurement results are as shown in Table 1.

(Measurement of N ₂ permeation amount of support on which second zeolite crystal is formed)
After the formation of the second zeolite crystal, the sample No. The permeation amount of N ₂ gas in 1 to 12 (hereinafter referred to as “second N ₂ permeation amount”) was measured. Specifically, N ₂ gas of 100 KPa was introduced into the cell of the support, and the second N ₂ permeation amount permeated through the support on which the first and second zeolite crystals were formed was measured with a mass flow meter. The measurement results are as shown in Table 1.

(Measurement of water permeability and separation factor of zeolite membrane)
In order to evaluate the performance of the zeolite membrane of each sample, the amount of water permeation and the separation factor were measured.

Specifically, a mixture of 50 ° C. water and ethanol mixed at a weight ratio of 50:50 is supplied to the zeolite membrane, and when the pressure on the permeate side is 50 torr, the vapor that has permeated the zeolite membrane is recovered with liquid N ₂ . Then, the weight of the collected permeate was measured. Then, water and ethanol components in the collected permeate were analyzed with a hydrometer, and the water permeation amount was calculated from the water and ethanol concentrations.

  Further, based on the formula of (permeate concentration / permeate ethanol concentration) / (supply water concentration / supply ethanol concentration), a separation coefficient indicating separation performance was calculated.

  As shown in Table 1, sample no. In Nos. 13 and 15, the hydrothermal synthesis time of the first zeolite crystals was reduced to 18 hours, so that the water permeation amount was good but the separation factor was low. Sample No. In No. 14, the hydrothermal synthesis time of the first zeolite crystals was increased to 38 hours to increase the film thickness, so that the separation factor was good but the water permeation amount was low. This confirms that it is difficult to achieve both separation and permeability when a single zeolite seed crystal is grown to form a zeolite membrane.

  On the other hand, sample no. In 1 to 12, both the water permeation amount and the separation factor were good. This is because the gap (film defect) of the first zeolite crystals could be filled in a short time by growing the second zeolite seed crystals applied after the formation of the first zeolite crystals. From this, it was confirmed that the separation and permeability of the zeolite membrane could be improved by growing the zeolite seed crystals with a time difference.

In addition, sample No. 1 in which the coating amount of the second zeolite seed crystal was smaller than that of the first zeolite seed crystal. In 1-4 and 7-12, the amount of water permeation was able to be improved more. This is because the entire thickness of the zeolite membrane could be reduced by reducing the thickness of the applied second zeolite seed crystal itself. In particular, sample No. ^{2 in} which the coating amount of the second zeolite seed crystal was less than 0.1 g / m ² . In 7 and 8, the water permeation amount was remarkably improved.

  In addition, sample No. 2 in which the average particle size of the second zeolite seed crystal was made smaller than that of the first zeolite seed crystal. In 9, 10, the separation factor could be further improved. This is because a fine second zeolite seed crystal can be efficiently put in the gap between the first zeolite crystals.

Sample No. 1 having a ratio of the first N ₂ permeation amount to the support N ₂ permeation amount (first N ₂ permeation amount / support N ₂ permeation amount) is 0.0008 or more and 0.5087. In 1-10, the separation factor was able to be improved more. This is because the second zeolite seed crystals could be efficiently put into the gaps of the first zeolite crystals because the gaps of the first zeolite crystals were set to an appropriate amount.

10 Separation Membrane Structure 20 Support 21 Base 22 Intermediate Layer 23 Surface Layer 30 Zeolite Membrane 31 First Zeolite Crystal 31a First Zeolite Seed Crystal 32 Second Zeolite Crystal 32a Second Zeolite Seed Crystal

Claims (5)

Applying a first seeding slurry containing a first zeolite seed crystal to a support;
Growing the first zeolite seed crystal to form a first zeolite crystal;
Applying a second seeding slurry containing a second zeolite seed crystal to the support on which the first zeolite crystal has been formed;
Growing the second zeolite seed crystal to form a second zeolite crystal;
A method for producing a zeolite membrane comprising: The coating amount of the second zeolite seed crystals per unit area is less than the coating amount of the first zeolite seed crystals per unit area.
The method for producing a zeolite membrane according to claim 1. The average particle size of the second zeolite seed crystal is smaller than the average particle size of the first zeolite seed crystal.
The manufacturing method of the zeolite membrane of Claim 1 or 2. The time for growing the second zeolite seed crystal to form the second zeolite crystal is shorter than the time for growing the first zeolite seed crystal to form the first zeolite crystal.
The method for producing a zeolite membrane according to any one of claims 1 to 3. Ratio transmission amount of _{N 2} gas in the support of the permeation amount of _{N 2} gas in the support to which the first zeolite crystals are formed is 0.0008 or more 0.5087,
The manufacturing method of the zeolite membrane in any one of Claims 1 thru | or 4.

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