Separation membrane structure and production method for separation membrane structure

Abstract

One aspect of the present invention provides a separation membrane structure comprising a porous support and a separation membrane, wherein: the separation membrane is provided to one surface side of the porous support, and includes a substance having pores or a component derived from a substance having pores; and the surface roughness (arithmetic average roughness Ra) of the surface of the separation membrane on the reverse side from the porous support is 1.3 μm or less, and the surface roughness (maximum height roughness Rz) of said reverse-side surface of the separation membrane is 10 μm or less.

Description

Separation membrane structure and method for manufacturing the separation membrane structure

[0001] The present disclosure relates to a separation membrane structure and a method for manufacturing a separation membrane structure.

[0002] Conventionally, methods for forming a zeolite membrane on a porous support using zeolite seed crystals have been known (see Patent Documents 1 and 2). In this method, the seed crystals applied to the surface of the porous support grow into a membrane-like crystal by hydrothermal synthesis, thereby forming a zeolite membrane.

[0003] JP 2004-82008 A JP 2008-74695 A

[0004] However, there is a problem in that the surface of a zeolite membrane formed by hydrothermal synthesis is prone to defects such as large irregularities and interconnected voids.

[0005] According to one aspect of the present invention, there is provided a separation membrane structure comprising a porous support and a separation membrane, the separation membrane being provided on one side of the porous support and containing a substance having pores or a component derived from the substance having pores, the surface roughness (arithmetic mean roughness Ra) of the separation membrane on the side opposite the porous support being 1.3 μm or less, and the surface roughness (maximum height roughness Rz) of the separation membrane on the side opposite the porous support being 10 μm or less.

[0006] According to this embodiment, it is possible to provide a separation membrane structure and a method for manufacturing a separation membrane structure in which defects such as large irregularities and interconnected voids are highly suppressed.

[0007] FIG. 1 is a cross-sectional view showing an embodiment of a separation membrane structure. FIG. 2 is a conceptual diagram showing an enlarged view of an example of powder. FIG. 3 is a schematic diagram showing an enlarged view of a cross section of a separation membrane structure manufactured using the powder of FIG. 2. FIG. 4 is a conceptual diagram showing an enlarged view of another example of powder. FIG. 5 is a schematic diagram showing an enlarged view of a cross section of a separation membrane structure manufactured using the powder of FIG. 4. FIG. 6 is a schematic diagram showing an embodiment of a manufacturing apparatus for a separation membrane structure that manufactures a tubular separation membrane structure. FIG. 7 is a block diagram of the manufacturing apparatus for the separation membrane structure shown in FIG. 6. FIG. 8 is a perspective view showing the relationship in size between a porous support and a nozzle. FIG. 9 is a side view (internal perspective view) showing an embodiment of a separation apparatus. FIG. 10 is a schematic diagram showing a water permeation separation test apparatus.

[0008] Hereinafter, embodiments of the present disclosure will be described. For each numerical range presented in this specification, the percentage of the separation membrane structure or the like that satisfies the numerical range is preferably about 85% or more, more preferably about 90% or more, and even more preferably about 95% or more, or may be 100%.

[0009] [Separation membrane structure] First, a separation membrane structure according to one embodiment will be described. FIG. 1 is a cross-sectional view showing an embodiment of the separation membrane structure. The separation membrane structure 1 shown in FIG. 1 comprises a porous support 2 and a separation membrane 3. The separation membrane 3 is provided on one surface 21 of the porous support 2, and contains a substance having pores or a component derived from a substance having pores. The porous support 2 supports the separation membrane 3. The porous support 2 may have any shape as long as it can supply a mixed fluid (liquid or gas) containing molecules to be separated to the separation membrane 3.

[0010] Examples of the shape of the porous support 2 include annular, square tubular, honeycomb, monolithic, flat, cylindrical, and rectangular pillar shapes. The porous support 2 is preferably tubular (annular or square tubular). In this case, the separation membrane structure 1 itself can be tubular, making it easier to configure the separation device 100 described below. In this case, the separation membrane 3 may be formed on either the outer peripheral surface side or the inner peripheral surface side of the porous support 2. However, considering the ease of forming the separation membrane 3, it is preferable to form it on the outer peripheral surface side of the porous support 2. In this case, the outer peripheral surface of the porous support 2 becomes one surface 21.

[0011] Examples of materials constituting the porous support 2 include ceramic materials, metal materials, glass materials, carbon materials, and hard resin materials. Examples of ceramic materials include alumina, mullite, zirconia, titania, yttria, silicon nitride, and silicon carbide. Examples of metal materials include aluminum or aluminum alloys, iron, stainless steel, titanium, and nickel. Examples of hard resin materials include fluorine-based resins such as polytetrafluoroethylene, polyethylene, polypropylene, polysulfone, polyphenylene sulfide, polycarbonate, polyamide, polyimide, and polyamideimide.

[0012] Among these, it is preferable that the material of the porous support 2 is at least one selected from the group consisting of alumina, mullite, stainless steel, titanium, nickel, and fluorine-based resin (particularly, polytetrafluoroethylene). By forming the porous support 2 from such a material, the mechanical strength of the porous support 2 can be improved, while also increasing the adhesion to the separation membrane 3.

[0013] The average pore diameter of the porous support 2 is preferably approximately 0.1 μm or more and 50 μm or less, and more preferably approximately 0.5 μm or more and 25 μm or less. A porous support 2 having an average pore diameter in this range can sufficiently increase the permeability of the molecules to be separated. The average pore diameter of the porous support 2 is the 50% diameter (so-called D50) in the volume cumulative pore size distribution of the porous support 2 measured using a pore distribution measuring device (e.g., a mercury porosimeter). The average particle diameter of the particles 20 constituting the porous support 2 is preferably approximately 1 μm or more and 500 μm or less, and more preferably approximately 10 μm or more and 100 μm or less.

[0014] In this specification, the "average particle size" can be determined, for example, as follows. The average particle size of the particles 20 can be determined by arithmetically averaging the equivalent circle diameters obtained in accordance with JIS Z8827-1:2018 (ISO13322-1:2014) based on an image acquired using a scanning electron microscope (SEM). That is, for example, 50 particles 20 that are entirely contained in a cross-sectional image of the porous support 2 acquired using an SEM are selected, the equivalent circle diameter for each selected particle 20 is obtained, and the arithmetic mean of the obtained equivalent circle diameters can be determined as the average particle size of the particles 20. Of course, other "average particle sizes" in this specification can also be obtained in a similar manner. Note that, in this specification, the porous support 2 has a microstructure in which the particles 20 are aggregated. However, the microstructure of the porous support 2 is not particularly limited as long as the porous support 2 sufficiently transmits the molecules to be separated and has sufficient mechanical strength.

[0015] A separation membrane 3 containing a substance having pores or a component derived from a substance having pores is provided on one surface 21 of the porous support 2. Examples of substances having pores include inorganic substances having a crystalline structure with pores, organic substances having a ring structure with pores, and metal-organic frameworks (MOFs) having a ring structure with pores. Due to their high durability and stability, inorganic substances and metal-organic frameworks are preferred as substances having pores.

[0016] Specific examples of such pore-containing substances include zeolites, metal-organic frameworks, metal oxides, metal nitrides, or mixtures thereof. These substances are preferred because they are easy to create (synthesize) with different pore sizes. Among these, it is preferable that at least a portion of the pore-containing substance be crystalline, and more preferably, 50% or more, 80% or more, or 90% or more of the pore-containing substance be crystalline. 100% of the pore-containing substance may be crystalline. The crystalline nature of the pore-containing substance makes it easier to predict and control the chemical and physical properties of the separation membrane 3, allowing the desired separation membrane structure 1 to be obtained. Whether the powder P or the separation membrane 3 containing the pore-containing substance is crystalline and the proportion of the crystalline substance can be evaluated by X-ray diffraction (XRD) measurement. Among these, the pore-containing substance is preferably zeolite. This makes it easier to control the chemical and physical properties of the separation membrane 3 by adjusting the crystal structure, element ratio (Si / Al ratio), etc., and the selectivity of the molecules to be separated by the separation membrane 3 can be further improved.

[0017] Zeolites include, for example, the codes given by the International Zeolite Society: AFI, AFR, AFS, AFY, ASV, ATO, ATS, BEA, BEC, BOG, BPH, BSV, CAN, CHA, CON, CZP, DFO, EMT, EON, EZT, FAU, FER, GME, GON, -HOS, IFR, ISV, ITG, IWR, IWS, IWV, IWW, and L TF, LTL, MAZ, MEI, MFI, MOR, MOZ, MSE, MTW, MWW, NPO, OFF, OKO, OSI, POS, PUN, -RON, RWY, SAF, SAO, SBE, SBS, SBT, SEW, SFE, SFO, SFS, SOF, SOR, SOS, SOV, SSF, SSY, UOV, USI, UWY, VET, and YFI.

[0018] On the other hand, examples of organic cyclic structures (ionophores) include structures containing at least one heteroatom such as an oxygen atom, a nitrogen atom, a sulfur atom, or a phosphorus atom (i.e., a structure in which methylene groups are bonded together via a heteroatom such as an oxygen atom, a nitrogen atom, a sulfur atom, or a phosphorus atom), or derivatives thereof, and structures composed only of methylene groups (hydrocarbon rings). Among these, preferred organic cyclic structures are structures in which methylene groups are bonded together via an oxygen atom, a nitrogen atom, a sulfur atom, or a phosphorus atom, or derivatives thereof.

[0019] Examples of such heteroatom-containing cyclic structures include structures having six or more carbon atoms and two or more types of at least one heteroatom in one ring. Specific examples of such cyclic structures include crown ether structures, propylene glycol structures, azacrown structures, thioether structures, and structures in which multiple crown rings are linked together.

[0020] In the separation membrane 3 described above, the surface roughness (arithmetic mean roughness Ra) of the outermost surface 321 of the separation membrane 3 (the surface opposite to the porous support 2) is preferably about 1.3 μm or less, more preferably about 1.2 μm or less, about 1.1 μm or less, about 1 μm or less, about 0.9 μm or less, about 0.8 μm or less, or about 0.7 μm or less, and even more preferably about 0.6 μm or less, about 0.5 μm or less, about 0.4 μm or less, or about 0.3 μm or less. With this configuration, the outermost surface 321 of the separation membrane structure 1 can be formed relatively smoothly and with little waviness, which makes it difficult for turbulence to occur in the mixed fluid containing the molecules to be separated near the outermost surface 321, and allows the molecules to be separated to pass (permeate, penetrate) more uniformly in the in-plane direction of the porous support 2.

[0021] Furthermore, the surface roughness (arithmetic mean roughness Ra) of the outermost surface (opposite surface) 321 of the separation membrane 3 may be approximately 0.1 μm or more, approximately 0.11 μm or more, approximately 0.12 μm or more, approximately 0.13 μm or more, approximately 0.14 μm or more, approximately 0.15 μm or more, approximately 0.16 μm or more, approximately 0.17 μm or more, approximately 0.18 μm or more, approximately 0.19 μm or more, or approximately 0.2 μm or more. By configuring in this manner, the outermost surface 321 of the separation membrane structure 1 can have appropriate unevenness, which can increase the area of ​​contact between the separation membrane 3 (outermost surface 321) and the mixed fluid containing the molecules to be separated, and can prevent a decrease in the permeability of the molecules to be separated.

[0022] That is, the surface roughness (arithmetic mean roughness Ra) of the outermost surface 321 of the separation membrane 3 may be, for example, about 0.1 μm to 1.3 μm, about 0.11 μm to 1.2 μm, about 0.12 μm to 1.1 μm, about 0.13 μm to 1 μm, about 0.14 μm to 0.9 μm, about 0.15 μm to 0.8 μm, about 0.16 μm to 0.7 μm, about 0.17 μm to 0.6 μm, about 0.18 μm to 0.5 μm, about 0.19 μm to 0.4 μm, or about 0.2 μm to 0.3 μm. The upper and lower limit values ​​of the surface roughness (arithmetic mean roughness Ra) of the outermost surface 321 can be combined as appropriate. The surface roughness (arithmetic mean roughness Ra) of the outermost surface 321 can be measured in accordance with JIS B0601:2013 (ISO4287:1997) using a surface profile measuring instrument in accordance with JIS B0651:2001 (ISO3274:1996).

[0023] The surface roughness (maximum height roughness Rz) of the outermost surface (opposite surface) 321 of the separation membrane 3 is preferably about 10 μm or less, and may be about 9.9 μm or less, about 9.8 μm or less, about 9.7 μm or less, about 9.6 μm or less, about 9.5 μm or less, about 9.4 μm or less, about 9.3 μm or less, about 9.2 μm or less, about 9.1 μm or less, about 9.0 μm or less, about 8.9 μm or less, or about 8.8 μm or less, It is more preferably about 8.7 μm or less, about 8.6 μm or less, about 8.5 μm or less, about 8.4 μm or less, about 8.3 μm or less, about 8.2 μm or less, or about 8.1 μm or less, and more preferably about 8 μm or less, about 7.9 μm or less, about 7.8 μm or less, about 7.7 μm or less, about 7.6 μm or less, about 7.5 μm or less, about 7.4 μm or less, about 7.3 μm or less, about 7.2 μm or less, or about 7 It is more preferably about 1 μm or less, and particularly preferably about 7 μm or less, about 6.9 μm or less, about 6.8 μm or less, about 6.7 μm or less, about 6.6 μm or less, about 6.5 μm or less, about 6.4 μm or less, about 6.3 μm or less, about 6.2 μm or less, about 6.1 μm or less, or about 6 μm or less, and particularly preferably about 5.9 μm or less, about 5.8 μm or less, about 5.7 μm or less, or about 5.6 μm or less. It is particularly preferable that the thickness be about 5.5 μm or less, about 5.4 μm or less, about 5.3 μm or less, about 5.2 μm or less, about 5.1 μm or less, about 5 μm or less, about 4.9 μm or less, about 4.8 μm or less, about 4.7 μm or less, about 4.6 μm or less, about 4.5 μm or less, about 4.4 μm or less, about 4.3 μm or less, about 4.2 μm or less, about 4.1 μm or less, or about 4 μm or less. With this configuration, defects such as large irregularities and interconnected voids are unlikely to occur on the outermost surface 321 of the separation membrane structure 1. Therefore, defects are unlikely to occur in the separation membrane 3, and it is possible to prevent molecules other than the molecules to be separated from passing through the separation membrane structure 1 without passing through the separation membrane 3.

[0024] The surface roughness (maximum height roughness Rz) of the outermost surface (opposite surface) 321 of the separation membrane 3 is about 1 μm or more, about 1.01 μm or more, about 1.02 μm or more, about 1.03 μm or more, about 1.04 μm or more, about 1.05 μm or more, about 1.06 μm or more, about 1.07 μm or more, about 1.08 μm or more, about 1.09 μm or more, about 1.1 μm or more, about 1.11 μm or more, about 1.12 μm or more, about 1.13 μm or more, about 1.14 μm or more, about 1.15 μm or more, about 1.16 μm or more, about 1.17 μm or more, about 1.18 μm or more, about 1.19 μm or more, about 1.2 μm or more, about 1.21 μm or more, about 1.22 μm or more, about 1.23 μm or more, about 1.2 It may be about 4 μm or more, about 1.25 μm or more, about 1.26 μm or more, about 1.27 μm or more, about 1.28 μm or more, about 1.29 μm or more, about 1.3 μm or more, about 1.31 μm or more, about 1.32 μm or more, about 1.33 μm or more, about 1.34 μm or more, about 1.35 μm or more, about 1.36 μm or more, about 1.37 μm or more, about 1.38 μm or more, about 1.39 μm or more, about 1.4 μm or more, about 1.41 μm or more, about 1.42 μm or more, about 1.43 μm or more, about 1.44 μm or more, about 1.45 μm or more, about 1.46 μm or more, about 1.47 μm or more, about 1.48 μm or more, about 1.49 μm or more, or about 1.5 μm or more. By configuring it in this manner, appropriate unevenness is created on the outermost surface 321 of the separation membrane structure 1, making it easier to ensure a sufficient contact area between the mixed fluid containing the molecules to be separated and the separation membrane 3 (outermost surface 321), and preventing a decrease in the permeability of the molecules to be separated.

[0025] That is, the surface roughness (maximum height roughness Rz) of the outermost surface 321 of the separation membrane 3 is, for example, about 1 μm to 10 μm, about 1.01 μm to 8 μm, about 1.02 μm to 7 μm, about 1.03 μm to 6.5 μm, about 1.04 μm to 6 μm, about 1.05 μm to 5.5 μm, about 1.06 μm to 5.4 μm, about 1.07 μm to 5.3 μm, about 1.08 μm to 5.2 μm, or about 1.09 μm to 5.1 μm. The surface roughness of the outermost surface 321 may be approximately 1.1 μm or more and 5.0 μm or less, approximately 1.11 μm or more and 4.9 μm or less, approximately 1.12 μm or more and 4.8 μm or less, approximately 1.13 μm or more and 4.7 μm or less, approximately 1.14 μm or more and 4.6 μm or less, approximately 1.15 μm or more and 4.5 μm or less, approximately 1.16 μm or more and 4.4 μm or less, approximately 1.17 μm or more and 4.3 μm or less, approximately 1.18 μm or more and 4.2 μm or less, approximately 1.19 μm or more and 4.1 μm or less, or approximately 1.2 μm or more and 4 μm or less. The upper and lower limit values ​​of the surface roughness (arithmetic mean roughness Ra) of the outermost surface 321 can be combined as appropriate. The surface roughness (maximum height roughness Rz) of the outermost surface 321 can be measured in accordance with JIS B0601:2013 (ISO4287:1997) using a surface profile measuring instrument in accordance with JIS B0651:2001 (ISO3274:1996).

[0026] In summary, the surface roughness (arithmetic mean roughness Ra) of the outermost surface 321 of the separation membrane 3 (the surface opposite to the porous support 2) is approximately 1.3 μm or less, and the surface roughness (maximum height roughness Rz) of the outermost surface 321 of the separation membrane 3 (the surface opposite to the porous support 2) is approximately 10 μm or less. The outermost surface 321 that satisfies these conditions is a surface that has little waviness and does not have defects such as large irregularities. Therefore, in order to prevent turbulence from occurring in the mixed fluid containing the molecules to be separated near the outermost surface 321, the molecules to be separated can be easily passed uniformly in the in-plane direction of the porous support 2, and molecules other than the molecules to be separated can be prevented from passing through the separation membrane structure 1. In other words, a separation membrane structure 1 having an outermost surface 321 that satisfies these conditions can improve the permeation amount of the molecules to be separated and suppress a decrease in separation performance, thereby enabling the molecules to be separated to be efficiently recovered. The proportion of outermost surface 321 of separation membrane 3 whose surface roughness satisfies the above range is preferably 85% or more, more preferably 90% or more, even more preferably 95% or more, and may be 100%.

[0027] The combination of the upper limit of the surface roughness (arithmetic mean roughness Ra) and the upper limit of the surface roughness (maximum height roughness Rz) of the outermost surface 321 of the separation membrane 3 can be, for example, the combinations shown in Table 1 below. In Table 1, a preferred combination is indicated as C, a more preferred combination as B, an even more preferred combination as A, and a particularly preferred combination as S. Furthermore, in Table 1, the smaller the upper limit of the surface roughness (arithmetic mean roughness Ra), the smoother the outermost surface 321 will be with fewer waviness and irregularities, and the smaller the upper limit of the surface roughness (maximum height roughness Rz), the fewer defects such as large irregularities and interconnected voids will be in the outermost surface 321.

[0028]

[0029] Furthermore, the average length RSm of the roughness curve elements of the outermost surface (opposite surface) 321 of the separation membrane 3 is preferably approximately 5 μm or more and 60 μm or less, more preferably approximately 8 μm or more and 55 μm or less, and even more preferably approximately 10 μm or more and 50 μm or less. Thus, a small average length RSm of the roughness curve elements of the separation membrane 3 can prevent or suppress the occurrence of alternating regions of different thicknesses in the in-plane direction of the separation membrane 3. Therefore, the chemical and physical properties of the separation membrane 3 become relatively uniform in the in-plane direction, improving the quality of the separation membrane 3. Furthermore, the variation in stress applied to the outermost surface 321 of the separation membrane 3 can be reduced, improving the durability of the separation membrane 3. Furthermore, having a certain size of the average length RSm of the roughness curve elements makes it difficult for excessively sharp irregularities to occur on the outermost surface 321 of the separation membrane 3. This makes it possible to prevent or suppress damage such as chipping on the outermost surface 321.

[0030] Furthermore, when the average thickness of the first portion 31 of the separation membrane 3 that penetrates into the porous support 2 is T1 [μm] and the average thickness of the second portion 32 of the separation membrane 3 excluding the first portion 31 is T2 [μm], T1 / T2 is preferably about 1 / 6 or less, more preferably about 1 / 8 or less, and even more preferably about 1 / 10 or less. With this configuration, the average thickness T1 of the first portion 31 is sufficiently small, so that it is possible to prevent or suppress high blockage of the pores on one surface 21 of the porous support 2. This makes it possible to sufficiently ensure the permeability of the molecules to be separated in the porous support 2.

[0031] Furthermore, the ratio T1 / T2 of the average thickness T1 [μm] of the first portion 31 of the separation membrane 3 to the average thickness T2 [μm] of the second portion 32 may be approximately 1 / 1000 or more, approximately 1 / 500 or more, or approximately 1 / 250 or more. By ensuring a certain level of average thickness T1 in this way, it is possible to improve the adhesion between the porous support 2 and the separation membrane 3. That is, the ratio T1 / T2 of the average thickness T1 [μm] of the first portion 31 of the separation membrane 3 to the average thickness T2 [μm] of the second portion 32 may be approximately 1 / 1000 or more and 1 / 6 or less, approximately 1 / 500 or more and 1 / 8 or less, or approximately 1 / 250 or more and 1 / 10 or less.

[0032] The "average thickness" of each portion is the arithmetic mean value of thicknesses measured at at least three locations by cross-sectional microstructural observation using a SEM (scanning electron microscope). The at least three locations are selected to be at least 20 μm apart in the in-plane direction of the separation membrane 3. Furthermore, when measuring at each location, it is preferable to measure the thickness of the first portion 31 and the thickness of the second portion 32 so that they are positioned on the same straight line in the thickness direction of the separation membrane 3 (separation membrane structure 1).

[0033] When the interface between the porous support 2 and the separation membrane 3, which is the boundary between the first portion 31 and the second portion 32, is unclear, the interface can be identified, for example, using a scanning electron microscope (SEM)-energy dispersive X-ray spectroscopy (EDX). That is, in observing the cross-sectional microstructure of the separation membrane structure 1, a measurement area is used in which the in-plane direction of the separation membrane structure 1 is the long side and the thickness direction of the separation membrane structure 1 is the short side, and the long side is set to be at least 10 times the length of the short side. At each location where the thickness of the first portion 31 and the thickness of the second portion 32 are measured, the measurement area is moved from the outermost surface 321 of the separation membrane 3 toward the porous support 2 along the thickness direction of the separation membrane 3. At this time, the measurement areas before and after each movement are made not to overlap with each other. Elemental analysis is performed on each measurement area. Then, for example, a graph of each component detected by elemental analysis is created, and the thickness of the first portion 31 and the thickness of the second portion 32 are measured at the interface between the porous support 2 and the separation membrane 3, where the composition of the most frequently detected component changes or the inflection point where the concentration ratio of an element specific to the separation membrane 3 changes significantly. Here, the dashed dotted line in Figure 1 indicates the average thickness of the first portion 31 and the second portion 32. The first portion 31 can also be called a composite portion where the constituent material of the separation membrane 3 and the constituent material of the porous support 2 are composited.

[0034] It has been difficult to form a separation membrane 3 that satisfies this relationship in the past. In conventional hydrothermal synthesis methods, seed crystals applied to the surface of a porous support diffuse into the interior of the porous support, which tends to increase the effective thickness of the formed zeolite membrane, and depending on the viscosity and flow rate of the mixed fluid containing the molecules to be separated, the permeability of the molecules to be separated may decrease. In particular, when attempting to grow a zeolite membrane to a sufficient thickness, depending on the treatment conditions (temperature, time, etc.), the zeolite membrane tends to grow not only on the porous support but also toward the interior of the porous support.

[0035] For example, in Japanese Patent No. 6,882,561, an effort has been made to optimize the pore distribution on the outermost surface of the porous support and the particle size distribution of the seed crystals to suppress the diffusion of the seed crystals into the porous support. However, even with this method, it is difficult to suppress the diffusion of the seed crystals into the porous support, and if the pore distribution on the outermost surface of the porous support is made too small, the permeability of the molecules to be separated in the porous support itself tends to decrease. On the other hand, with the separation membrane structure 1 according to the above embodiment, there is no need to apply seed crystals to the surface of the porous support 2 in the first place, so the above-mentioned problems are less likely to occur. Therefore, the value of T1 / T2 can be kept small.

[0036] The average thickness T1 is preferably about 1 μm or less, more preferably about 0.8 μm or less, and even more preferably about 0.3 μm or less. This makes it possible to suitably suppress a decrease in the permeability of the molecules to be separated in the porous support 2 in the area where the first portion 31 is present. The average thickness T1 may be 0 μm. On the other hand, the average thickness T2 is preferably about 0.5 μm or more and 10 μm or less, more preferably about 0.8 μm or more and 8 μm or less, and even more preferably about 1.2 μm or more and 6 μm or less. This makes it possible to prevent a decrease in the permeability of the molecules to be separated in the second portion 32 while sufficiently maintaining the selectivity and mechanical strength of the molecules to be separated.

[0037] Furthermore, the separation membrane structure 1 preferably has acid resistance and water resistance. This allows the separation membrane structure 1 to fully demonstrate its separation performance even when the mixed fluid containing the molecules to be separated is acidic or when water molecules are to be separated. Furthermore, since deterioration of the separation membrane structure 1 can be prevented or suppressed and the separation membrane structure 1 can be used for a long period of time, the operating costs of the separation membrane structure 1 can be reduced. Furthermore, by using the separation membrane structure 1 for a long period of time, the environmental impact of the separation membrane structure 1 can be reduced and the life cycle assessment (LCA) can be improved.

[0038] More specifically, the ratio of the surface roughness (arithmetic mean roughness Ra) of the outermost surface (opposite surface) 321 after the separation membrane structure 1 has been immersed in a 50% by mass aqueous acetic acid solution at 80°C for 300 hours to the surface roughness (arithmetic mean roughness Ra) of the outermost surface (opposite surface) 321 before immersion in the acetic acid solution (i.e., the rate of change in surface roughness (arithmetic mean roughness Ra) before and after immersion in the acetic acid solution) is preferably about 0.5 to about 2, more preferably about 0.8 to about 1.8, even more preferably about 0.9 to about 1.6, and particularly preferably about 0.9 to about 1.4. Thus, when the change in the surface roughness (arithmetic mean roughness Ra) of the outermost surface 321 before and after immersion in the acetic acid solution is small, it can be said that the separation membrane structure 1 (separation membrane 3) is less susceptible to damage by an acidic solution or water. In other words, the separation membrane structure 1 is acid-resistant and water-resistant. More specifically, it is preferable that the ratio of the surface roughness (arithmetic mean roughness Ra) of the outermost surface 321 of the separation membrane structure 1 after it has been immersed in a 50 mass% acetic acid aqueous solution at 80°C for 300 hours, washed with ion-exchanged water, and left (dried) overnight at 70°C to the surface roughness (arithmetic mean roughness Ra) of the outermost surface 321 of the separation membrane structure 1 that has not been immersed in the acetic acid aqueous solution (i.e., before immersion or not immersed) satisfies the above-mentioned numerical range.

[0039] Furthermore, when the pore-containing substance is a zeolite, the content of aluminum atoms per 1 mol of silicon atoms in the separation membrane 3 is preferably about 1 / 10 mol or less, more preferably about 1 / 12 mol or less, and even more preferably about 1 / 40 mol or less (in other words, the Si / Al ratio is preferably about 10 or more, more preferably about 12 or more, and even more preferably about 40 or more). By satisfying these values, even if aluminum atoms, which are relatively prone to negative charge, are attacked by hydrogen ions, hydroxide ions, etc. and released, damage to the separation membrane structure 1 (separation membrane 3) can be prevented or suppressed. Note that when the aluminum atom content is small (i.e., the Si / Al ratio is large), the separation membrane 3 is also less likely to be damaged even in a high-temperature environment, even if aluminum atoms are released. In other words, the heat resistance of the separation membrane structure 1 (separation membrane 3) can also be improved.

[0040] The separation membrane 3 can be formed using powder P having a configuration as shown in Fig. 2. As described in detail below, the separation membrane 3 can be formed by spraying the powder P onto one surface 21 of the porous support 2. As a method for spraying the powder P onto one surface 21 of the porous support 2, it is preferable to adopt, for example, an aerosol deposition method.

[0041] FIG. 2 is a conceptual diagram showing an enlarged view of an example of a powder. FIG. 3 is a schematic diagram showing an enlarged view of a cross section of a separation membrane structure produced using the powder of FIG. 2. As shown in FIG. 2, the powder P is a collection of particles 3a containing a substance having pores. As described above, the substance having pores that constitutes the particles 3a may be either crystalline or amorphous. However, it is preferable that at least a portion of the substance having pores is crystalline. This appropriately improves the mechanical strength of the particles 3a, and it can be expected that the particles 3a will be sprayed against one surface 21 with sufficient collision energy. Furthermore, the constituent material of the particles 3a (substance having pores) is not limited to a single material, and may contain multiple types.

[0042] As shown in Figure 3, by spraying the powder P of Figure 2 onto one surface 21 of the porous support 2, a separation membrane 3 containing a particle-derived component 3a' can be formed. The particle-derived component 3a' includes at least one of the particles 3a themselves, a component formed by deformation (change in shape) of the particles 3a, and small pieces detached from the particles 3a. Of these, the particle-derived component 3a' preferably includes at least one of a component formed by deformation of the particles 3a and small pieces detached from the particles 3a. The particles 3a are sprayed onto one surface 21 and collide with the one surface 21 with such high collision energy that the particles 3a are deformed or partially detached, thereby forming the separation membrane 3. This increases the adhesion between the separation membrane 3 and the porous support 2, thereby improving the mechanical strength of the separation membrane structure 1.

[0043] The average particle size of the particles 3a is preferably about 0.01 μm to 100 μm, more preferably about 0.05 μm to 50 μm, and even more preferably about 0.1 μm to 10 μm, for example, about 0.3 μm to 0.6 μm. As shown in FIG. 3 , when the average particle size of the particles 3a is sufficiently small, the separation membrane 3 can be formed uniformly, homogeneously, and densely. Furthermore, when the average particle size of the particles 3a is relatively large, the powder P can have sufficient collision energy when sprayed onto one surface 21 of the porous support 2, making it easier to form the separation membrane 3. Furthermore, since the particles 3a of the powder P can adhere to the one surface 21 and the other particles 3a with sufficient strength, damage such as cracks and interconnected voids (through-holes) is less likely to occur in the separation membrane 3, thereby improving the quality of the separation membrane structure 1.

[0044] Furthermore, the powder P may have second particles 3b in addition to the particles 3a as the first particles. Fig. 4 is a conceptual diagram showing an enlarged view of another example of the powder. Fig. 5 is a schematic diagram showing an enlarged view of a cross section of a separation membrane structure produced using the powder of Fig. 4. In this case, as shown in Fig. 4, the powder P is an aggregate of first particles 3a and second particles 3b. The second particles 3b contain a substance that differs in at least one of crystal structure and chemical composition from the substance having the pores.

[0045] When the powder P includes first particles 3a and second particles 3b, the separation membrane 3 formed by spraying the first particles 3a against one surface 21 of the porous support 2 has a component 3b' derived from the second particles in addition to a component 3a' derived from the first particles, as shown in Figure 5. The component 3b' derived from the second particles is at least one of the second particles 3b themselves, a component formed by deformation (change in shape) of the second particles 3b, and small pieces detached from the second particles 3b. For the same reasons as for the component 3a' derived from the first particles, the component 3b' derived from the second particles preferably includes at least one of a component formed by deformation of the second particles 3b and small pieces detached from the second particles 3b.

[0046] That is, in this case, the separation membrane 3 has a component 3a' derived from the first particles and second particles 3b that differ from the first particle-derived component 3a' in at least one of the crystal structure and chemical composition, and thus can have multiple properties and functions. In particular, by forming the separation membrane structure 1 using a method such as aerosol deposition, as shown in FIG. 5 , regions of the component 3b' derived from the second particles can be substantially uniformly dispersed (scattered) within regions of the component 3a' derived from the first particles in the cross section of the separation membrane 3. Therefore, a relatively uniform and homogeneous separation membrane 3 can be formed while having multiple properties and functions. This makes it possible to reduce variations in the permeation rate and selectivity of molecules to be separated in the in-plane direction of the separation membrane 3. Furthermore, the chemical and physical properties of the separation membrane 3 can be easily predicted and controlled, and a desired separation membrane structure 1 can be obtained.

[0047] The average particle size of the second particles 3b is preferably about 0.1 μm or more and 100 μm or less, more preferably about 0.3 μm or more and 50 μm or less, and even more preferably about 0.5 μm or more and 10 μm or less, and can be, for example, about 0.9 μm or more and 1.1 μm or less.

[0048] It is more preferable that the average particle size of the second particles 3b is larger than the average particle size of the first particles 3a. In this case, since the average particle size of the first particles 3a is small, even if the collision energy of the first particles 3a is small when the powder P is sprayed onto one surface 21 of the porous support 2 and the powder P collides with the one surface 21 to form the separation membrane 3, the second particles 3b can impart collision energy to the entire powder P. Therefore, the separation membrane 3 can be reliably formed, and the separation membrane 3 can be adhered to the one surface 21 with sufficient strength.

[0049] Here, when the average particle size of the second particles 3b is larger than the average particle size of the first particles 3a (for example, the average particle size is about 0.5 μm or more), it is preferable that the second particles 3b are less likely to be incorporated into the separation membrane 3. This can prevent or suppress impairment of the density and homogeneity of the separation membrane 3. More specifically, the area ratio of the region composed of the second particle-derived component 3b' to the cross-sectional area of ​​the separation membrane 3 is preferably about 50% or less, more preferably about 40% or less, and even more preferably about 30% or less. The area ratio of the region composed of the second particle-derived component 3b' is about 0% or more. The area ratio of the region composed of the second particle-derived component 3b' can be obtained, for example, by cross-sectional microstructural analysis using an SEM or SEM-EDX device. Specifically, an image of a predetermined region (for example, a range of 1 μm in the thickness direction × 10 μm in the in-plane direction) in the cross section of the separation membrane 3 is obtained using the SEM or SEM-EDX device. By measuring the total area of ​​the separation membrane 3 in this image and the total area of ​​the region constituted by the component 3b' derived from the second particles, the ratio of the area constituted by the component 3b' derived from the second particles can be obtained.

[0050] By mixing the first particles 3 a and the second particles 3 b under the following conditions, it is possible to appropriately reduce the number of the second particles 3 b that are captured in the separation membrane 3. Furthermore, by including a sufficient amount of the second particles 3 b in the powder P, it is possible to impart an appropriate amount of collision energy to the powder P, thereby facilitating the formation of the separation membrane 3.

[0051] That is, the loose bulk density of the powder P as a whole is 0.3 g / cm３ It is preferable that the density is about 0.4 g / cm or more. ３ It is more preferable that the loose bulk density is about 100 mL or more. The loose bulk density can be measured according to JIS K7365:1999 (ISO60:1977) or a method conforming thereto. That is, powder P is gently poured into a 100 mL container using a funnel without applying any physical external force (tapping, pushing, etc.), and the weight of powder P when the container is leveled is divided by the volume (100 mL) to obtain the loose bulk density.

[0052] Furthermore, when the cumulative 10% diameter in the volume-based particle size distribution of powder P is defined as D10 and the cumulative 90% diameter is defined as D90, it is preferable that D10 is approximately 0.05 μm or more and 1.0 μm or less, and D90 is approximately 0.8 μm or more and 5 μm or less, and it is more preferable that D10 is approximately 0.1 μm or more and 0.8 μm or less, and D90 is approximately 1 μm or more and 4 μm or less. These values ​​are examples of particularly preferred ranges and can be combined with each other. Note that this particle size distribution can be measured, for example, using a particle size distribution measuring device using a laser diffraction / scattering method. Then, based on the obtained particle size distribution, the particle size at the 10% cumulative diameter from the smallest particle size side can be calculated as D10, and the particle size at the 90% cumulative diameter from the smallest particle size side can be calculated as D90.

[0053] That is, the powder P containing first particles 3a and second particles 3b larger in diameter than the first particles 3a preferably has two maxima in its volumetric particle size frequency distribution. The powder P may also contain particles with different average particle sizes in addition to the first particles 3a and the second particles 3b. In this case, the particle size distribution of the powder P may have three or more maxima. Thus, when the difference in average particle size between the first particles 3a and the second particles 3b is sufficiently large, the first particles 3a have a sufficiently small average particle size, which allows the separation membrane 3 to be formed uniformly, homogeneously, and densely, while the second particles 3b have a sufficiently large average particle size, which makes it easy to impart sufficient and appropriate collision energy to the entire powder P. In other words, the powder P preferably contains two or more types of particles exhibiting different particle size distributions. The maxima of these different particle size distributions correspond to two or more maxima of the powder P.

[0054] Examples of materials for the second particles 3b include various oxides and nitrides. Among these, the constituent material of the second particles 3b is preferably at least one selected from inorganic oxides such as titanium oxide (titanium dioxide or titanium trioxide), aluminum oxide, and silicon oxide, and inorganic nitrides such as aluminum nitride and boron nitride. Second particles 3b made of these materials are readily available and relatively inexpensive, thereby suppressing increases in the production cost of the separation membrane structure 1. Furthermore, the material for the second particles 3b may be a substance having fine pores, such as zeolite, a metal-organic framework, a metal oxide, a metal nitride, or a mixture thereof. In this case, even if the component 3a' derived from the first particles is unable to capture the molecules to be separated, the component 3b' derived from the second particles can capture the molecules to be separated, thereby improving permeability to the molecules to be separated. From the viewpoint of both reducing production costs and improving permeability, it is particularly preferable to use a metal oxide or a metal nitride as the material for the second particles 3b.

[0055] [Manufacturing Method of Separation Membrane Structure] Next, a manufacturing method of a separation membrane structure will be described. The manufacturing method of a separation membrane structure includes a step (first step) of preparing a powder P containing at least particles 3a (substances) having pores and a porous support 2, and a step (second step) of spraying the powder P onto one surface 21 of the porous support 2 to form a separation membrane 3, thereby obtaining a separation membrane structure 1.

[0056] (First Step) First, a powder P containing at least particles 3a having pores and a porous support 2 are prepared. Both the powder P and the porous support 2 may be commercially available or may be prepared by hand. In the latter case, the powder P can be prepared by, for example, hydrothermal synthesis. The pore size and the type of crystal structure can be changed by changing the raw materials and conditions used in the hydrothermal synthesis. A structure-directing agent may also be used to adjust the pore size. When the powder P is composed of multiple types of particles, it is advisable to further mix the prepared or purchased particles in a wet or dry manner.

[0057] On the other hand, the porous support 2 can be produced, for example, as follows. First, a molded body containing the particles 20, an organic binder, and, if necessary, a pH adjuster and a surfactant is formed. For molding the molded body, for example, injection molding, extrusion molding, press molding, etc. can be used. Next, the molded body is fired to obtain the porous support 2. The firing conditions can be, for example, about 900°C or higher and 1450°C or lower, and about 1 hour or higher and 100 hours or lower. Note that the organic binder may be removed by this firing, or a degreasing step for removing the organic binder may be provided prior to firing.

[0058] (Second Step) Next, a membrane is formed by spraying the powder P onto one surface 21 of the porous support 2. Examples of spraying methods include aerosol deposition, spray coating, and electrodeposition coating. Among these, in the second step (the step of obtaining the separation membrane structure 1), it is preferable to spray the powder P onto one surface 21 of the porous support 2 by aerosol deposition. By employing the aerosol deposition method, membrane formation can be performed at room temperature, thereby reducing power consumption.

[0059] The particles 3a (or the first particles 3a and the second particles 3b) in the powder P sprayed toward the surface 21 of the porous support 2 collide with and deposit on one surface 21 of the porous support 2, thereby forming a separation membrane 3 on that surface 21. At this time, at least some of the particles 3a (or the first particles 3a and the second particles 3b) may be deformed during the process of forming the separation membrane 3, or some of them may detach and adhere. Furthermore, when the powder P contains second particles 3b, it is preferable that many of the second particles 3b fall, float, or adhere to the inner surface of the chamber within the chamber, so that the mass ratio of the component 3b' derived from the second particles in the separation membrane 3 is significantly smaller than the mass ratio of the second particles 3b to the powder P, and the area ratio of the region composed of the component 3b' derived from the second particles in the separation membrane 3 becomes smaller. In this manner, the separation membrane structure 1 can be obtained.

[0060] [Separation Membrane Structure Manufacturing Apparatus] Hereinafter, a separation membrane structure manufacturing apparatus 4 that manufactures a separation membrane structure 1 by forming a separation membrane 3 using an aerosol deposition method will be described. In this specification, a case in which the separation membrane 3 is formed over the entire outer peripheral surface (one surface 21) of a tubular porous support 2 will be described as an example.

[0061] Incidentally, a program for realizing the software appearing in one embodiment may be provided as a non-transitory computer-readable recording medium, or may be provided so as to be downloadable from an external server, or may be provided so that the program is started on an external computer and its functions are realized on a client terminal (so-called cloud computing).

[0062] Furthermore, various information processing according to an embodiment may realize input and output corresponding to the input. Here, the form of information referenced in such information processing (hereinafter referred to as reference information) is not limited as long as an output is obtained as a result of the input. The reference information may be, for example, rule-based information such as a database, a lookup table, or a predetermined function (including a determination formula such as a regression formula constructed using a statistical method), a trained model that has previously learned the correlation between input and output, or a generative AI such as a large-scale language model or a visual language model that can output a desired result by inputting a prompt.

[0063] In one embodiment, the term "unit" may include, for example, a combination of hardware resources implemented by a circuit in the broad sense and software information processing that can be specifically realized by these hardware resources. In one embodiment, various information is handled, and this information is represented, for example, by physical values ​​of signal values ​​representing voltage or current, high or low signal values ​​as a binary bit set consisting of 0 or 1, or quantum superposition (so-called quantum bits), and communication and calculations can be performed on the circuit in the broad sense.

[0064] Furthermore, a circuit in a broad sense is a circuit realized by at least an appropriate combination of a circuit, circuitry, a processor, a memory, etc. The processor may be a general-purpose processor or a dedicated circuit. That is, it includes application specific integrated circuits (ASICs), programmable logic devices (e.g., simple programmable logic devices (SPLDs), complex programmable logic devices (CPLDs), and field programmable gate arrays (FPGAs)), etc.

[0065] FIG. 6 is a schematic diagram showing an embodiment of a separation membrane structure manufacturing apparatus for manufacturing a tubular separation membrane structure. FIG. 7 is a block diagram of the separation membrane structure manufacturing apparatus shown in FIG. 6. FIG. 8 is a perspective view showing the relationship between the size of the porous support and the nozzle. The separation membrane structure manufacturing apparatus 4 shown in FIG. 6 includes a chamber 5, a support mechanism 6 that supports a tubular porous support 2 within the chamber 5, and a spray mechanism 7 that sprays powder P containing at least pore-containing particles 3a toward the porous support 2. The average particle size of the particles 3a (or the first particles 3a and the second particles 3b) contained in the powder P is preferably approximately 0.1 μm or more and 50 μm or less, and more preferably approximately 0.5 μm or more and 35 μm or less. This allows the powder P to be sprayed at a higher speed from the spray outlet 711 of the nozzle 71.

[0066] The support mechanism 6 has a support rod 61 inserted inside the tubular porous support 2 and a motor 62 that rotates the support rod 61. The motor 62 is rotated while the porous support 2 is supported by the support rod 61. The support mechanism 6 is configured to rotate the tubular porous support 2 about its central axis. This configuration makes it easy to form a uniform and homogeneous separation membrane 3 on the outer peripheral surface (one surface 21) of the porous support 2 along the circumferential direction of the porous support 2. The rotation speed of the porous support 2 is preferably approximately 1 rpm or more and 60 rpm or less, and more preferably approximately 5 rpm or more and 30 rpm or less. Rotating the porous support 2 at such a rotation speed makes it easy to improve the uniformity and homogeneity of the separation membrane 3 along the circumferential direction of the porous support 2.

[0067] The ejection mechanism 7 has a nozzle 71 that ejects the powder P, and is configured to move the nozzle 71 along the central axis (longitudinal direction) of the porous support 2 using a moving mechanism 78 (see FIG. 7 ). This configuration facilitates the formation of a uniform and homogeneous separation membrane 3 along the longitudinal direction of the porous support 2 on the outer peripheral surface (one surface 21) of the porous support 2. The moving speed of the nozzle 71 is preferably approximately 0.1 cm / sec to 30 cm / sec, and more preferably approximately 0.5 cm / sec to 20 cm / sec. Moving the nozzle 71 at this moving speed facilitates the enhancement of the uniformity and homogeneity of the separation membrane 3 along the longitudinal direction of the porous support 2. In the ejection mechanism 7, the nozzle 71 is connected to a gas cylinder 72 via a transfer pipe 73. A mass flow controller 74 and an aerosol generator 75 are provided in the transfer pipe 73, in this order from the gas cylinder 72 side.

[0068] In the separation membrane structure manufacturing apparatus 4, a carrier gas is supplied from a gas cylinder 72 to a carrier pipe 73, and the flow rate of the carrier gas is adjusted by a mass flow controller 74. An aerosol generator 75 is loaded with powder P to be sprayed, and the powder P is dispersed in the carrier gas flowing through the carrier pipe 73 to transport the powder P to the nozzle 71. That is, the jetting mechanism 7 is equipped with the aerosol generator 75 that mixes the powder P with the carrier gas to generate an aerosol. The powder P is then jetted from the nozzle 71 onto the outer peripheral surface of the porous support 2 at a jetting speed of approximately equal to or greater than subsonic speed and equal to or less than supersonic speed. In addition, a pump 81 is connected to the chamber 5 as a pressure reducing mechanism 8, and the pressure within the chamber 5 can be adjusted.

[0069] The separation membrane structure manufacturing apparatus 4 further includes a control means 9. The control means 9 is configured to control the operation of the separation membrane structure manufacturing apparatus 4. As shown in Fig. 7, the motor 62, the moving mechanism 78, and the pump 81 are each electrically connected to the control means 9. Although not shown, the control means 9 is also electrically connected to an operation unit, a display unit, a power supply unit, and the like. The control means 9 incorporates calculation units 91 and 92.

[0070] The calculation unit 91 is composed of, for example, a CPU (Central Processing Unit), an MPU (Micro Processing Unit), etc. The calculation unit 91 realizes various functions related to the separation membrane structure manufacturing apparatus 4 by reading out predetermined programs stored in the storage unit 92. In other words, information processing by the software stored in the storage unit 92 is specifically realized by the calculation unit 91. The calculation unit 91 is not limited to being a single unit, and multiple calculation units 91 may be provided for each function. A combination of these may also be used. In particular, it is preferable to provide a calculation unit 91 for controlling the operation of the motor 62, separate from the calculation unit 91 related to the movement of the nozzle 71 by the movement mechanism 78.

[0071] The memory unit 92 stores various pieces of information defined above. This can be implemented, for example, as a storage device such as a solid state drive (SSD) that stores various programs and the like related to the separation membrane structure manufacturing apparatus 4 executed by the calculation unit 91, or as a memory such as a random access memory (RAM) that stores temporarily required information (arguments, arrays, etc.) related to the program calculations. The memory unit 92 also stores various programs, variables, etc. related to the separation membrane structure manufacturing apparatus 4 executed by the calculation unit 91.

[0072] A method for manufacturing a separation membrane structure using such a manufacturing apparatus 4 for a separation membrane structure will now be described. First, the porous support 2 is attached to the support rods 61 of the support mechanism 6. Then, the chamber 5 is depressurized. The pressure within the chamber 5 (depressurized pressure) is not particularly limited, but is preferably about 5 Pa or more and 1000 Pa or less. By depressurizing to this level, convection within the chamber 5 is suppressed, making it easier to spray powder onto one surface 21 of the porous support 2. In this state, the motor 62 is operated to start rotation of the porous support 2 about its central axis.

[0073] Next, a carrier gas is supplied from a gas cylinder 72 to a carrier pipe 73, and while the flow rate of the carrier gas is adjusted by a mass flow controller 74, the carrier gas is supplied to an aerosol generator 75 filled with powder P. This causes the powder P to be dispersed and accelerated in the carrier gas, generating an aerosol. The aerosol (powder P) is then sprayed from a nozzle 71 toward one surface 21 of the porous support 2. At this time, an inert gas may be supplied to the aerosol, and the aerosol may be further accelerated by the supply pressure of at least one of the carrier gas and the inert gas.

[0074] The carrier gas may be, for example, oxygen (O ２ ), nitrogen (N ２Gases such as argon (Ar), helium (He), or air can be used. The flow rate and flow rate of the carrier gas can be set appropriately depending on the amount of aerosol supplied, the constituent material, average particle size, flow rate, and flow rate of the powder P sprayed from the nozzle 71. The flow rate and flow rate of the carrier gas can also be set in conjunction with the flow rate and flow rate of the inert gas. The aerosol is sprayed from the nozzle 711 of the nozzle 71 at a speed greater than or equal to subsonic and less than or equal to supersonic to deposit the powder on one surface 21 of the porous support 2. At this time, the spray rate of the aerosol (powder P) onto one surface 21 of the porous support 2 is preferably set to approximately 10 m / s or more and 1000 m / s or less, and more preferably set to approximately 10 m / s or more and 250 m / s or less. At this time, the nozzle 71 can be moved along the central axis of the porous support 2 as needed.

[0075] Here, as shown in Figure 8, when the nozzle 71 has a rectangular outlet 711 for ejecting powder P, when the outer diameter of the porous support 2 is R [mm] and the length of the outlet 711 along the radial direction of the porous support 2 is W [mm], it is preferable that W / R is approximately 0.1 or more and 1 or less, more preferably 0.2 or more and 0.8 or less, and even more preferably 0.3 or more and 0.6 or less.

[0076] By designing in this way, W / R is sufficiently small, and it is possible to prevent the formation of unintended gaps when the powder P is deposited on one surface 21 of the porous support body 2. In other words, it is possible to prevent the formation of defects such as cracks or interconnected voids, excessively large irregularities, etc. in the separation membrane 3, thereby improving the quality of the separation membrane 3.

[0077] Furthermore, since W / R is sufficiently large, it is possible to prevent the powder P from depositing more densely than necessary when it is deposited on one surface 21 of the porous support 2. This improves the productivity of the separation membrane 3. That is, by setting W / R within the above range, it is possible to form a high-quality separation membrane with high productivity.

[0078] The specific value of the width W is not particularly limited, but is preferably about 1 mm to 50 mm, more preferably about 5 mm to 40 mm, and even more preferably about 10 mm to 30 mm. In this case, a sufficient amount of powder P can be ejected onto the porous support 2, and the above-mentioned effect can be further improved.

[0079] The particles 3a (or the first particles 3a and the second particles 3b) contained in the powder P collide with the porous support 2, and at least some of them are crushed (pulverized) and / or deformed, and are deposited on one surface 21 of the porous support 2. At this time, when the second particles 3b are used, it is preferable that most of them do not deposit but fall, float, or adhere to the inner surface of the chamber 5 within the chamber 5. By the above steps, a separation membrane 3 having a predetermined thickness is obtained.

[0080] In addition to the nozzle 71 that sprays the powder P, a nozzle that sprays gas may be provided near the position on one surface 21 of the porous support body 2 where the powder P is sprayed. This makes it possible to remove excess powder P on one surface 21 of the porous support body 2 (powder P that could not be bonded to one surface 21). The removed powder P may be collected and reused as material for the powder P.

[0081] Furthermore, regardless of whether or not a nozzle for spraying gas is used, the powder P that has fallen, adhered, or floated in the chamber 5 without being able to form the separation membrane 3 may be collected and reused as material for the powder P. That is, the method for manufacturing a separation membrane structure may further include a recycling step, after the second step, of reusing at least a portion of the powder P that was not used to form the separation membrane 3. In this case, it is possible to reduce the amount of powder P produced when manufacturing the separation membrane 3 and the amount of powder P that was not used to form the separation membrane 3 that is discarded. Therefore, it is possible to reduce the environmental impact and manufacturing costs incurred when manufacturing the separation membrane structure 1.

[0082] According to the manufacturing method described above (particularly, the aerosol deposition method), it is possible to form a separation membrane 3 on one surface 21 of the porous support 2, while suppressing the occurrence of defects such as large irregularities and interconnected voids on the outermost surface 321. Furthermore, it is possible to selectively form the separation membrane 3 on one surface 21 of the porous support 2, while preventing or suppressing the separation membrane 3 from being formed inside the porous support 2. A separation membrane 3 having such a configuration is difficult to form by conventional hydrothermal synthesis methods.

[0083] The separation membrane structure manufacturing apparatus 4 is not limited to the above-described configuration, and various omissions, substitutions, and modifications can be made. For example, the porous support 2 may be flat, in which case a stage or arm or the like that holds the flat porous support is disposed above the nozzle of the separation membrane structure manufacturing apparatus 4. Furthermore, although the case where the separation membrane structure 1 is manufactured by moving the nozzle 71 of the separation membrane structure manufacturing apparatus 4 without moving the porous support 2 has been described, the separation membrane structure 1 may also be manufactured by fixing the nozzle 71 of the separation membrane structure manufacturing apparatus 4 and moving the porous support 2 in an in-plane direction facing the nozzle 711 of the nozzle 71.

[0084] Next, a separation device 100 including a tubular separation membrane structure 1 will be described. FIG. 9 is a side view (internal perspective view) showing an embodiment of the separation device. The separation device 100 shown in FIG. 9 includes a plurality of separation membrane structures 1 and a housing 200 that houses the plurality of separation membrane structures 1 in an internal space 201. Each separation membrane structure 1 is tubular. In other words, the separation device 100 is a multi-tube type device. Such a multi-tube type separation device 100 can ensure sufficient opportunity for contact between the separation membrane structure 1 and a mixed fluid (liquid or gas) containing molecules to be separated. As a result, the molecules to be separated can be separated smoothly and reliably.

[0085] The mixed fluid may be passed through the inside of each separation membrane structure 1 or the outside of each separation membrane structure 1 (i.e., the internal space 201 of the housing 200). For example, when the mixed fluid is passed through the inside of each separation membrane structure 1, the separated molecules move into the internal space 201 of the housing 200. To efficiently recover these separated molecules, the internal space 201 may be depressurized or a sweep gas may be supplied. The present disclosure as described above can provide a separation membrane structure 1, a method for producing the separation membrane structure 1, and a separation device 100 that have excellent permeability for the molecules to be separated by highly suppressing the formation of a separation membrane 3 inside the porous support 2. Furthermore, the present disclosure may be provided in the following aspects.

[0086] (1) A separation membrane structure comprising a porous support and a separation membrane, the separation membrane being provided on one side of the porous support and containing a substance having pores or a component derived from the substance having pores, the surface of the separation membrane opposite the porous support having a surface roughness (arithmetic mean roughness Ra) of 1.3 μm or less, and the surface of the separation membrane opposite the porous support having a surface roughness (maximum height roughness Rz) of 10 μm or less.

[0087] (2) The separation membrane structure according to (1) above, wherein the surface roughness (arithmetic mean roughness Ra) of the opposite surface of the separation membrane is 0.1 μm or more.

[0088] (3) The separation membrane structure according to (1) or (2) above, wherein the average length RSm of the roughness curve elements on the opposite surface of the separation membrane is 5 μm or more and 60 μm or less.

[0089] (4) In the separation membrane structure described in any one of (1) to (3) above, the ratio of the surface roughness (arithmetic mean roughness Ra) of the opposite surface after immersion in a 50 mass% acetic acid aqueous solution at 80°C for 300 hours to the surface roughness (arithmetic mean roughness Ra) of the opposite surface before immersion in the acetic acid aqueous solution is 0.5 or more and 2 or less.

[0090] (5) The separation membrane structure according to any one of (1) to (4) above, wherein the surface roughness (maximum height roughness Rz) of the opposite surface of the separation membrane is 1 μm or more.

[0091] (6) The separation membrane structure according to any one of (1) to (5) above, wherein the substance having the pores is crystalline.

[0092] (7) In the separation membrane structure described in any one of (1) to (6) above, when the average thickness of the first portion of the separation membrane embedded in the porous support is T1 [μm] and the average thickness of the second portion of the separation membrane excluding the first portion is T2 [μm], T1 / T2 is 1 / 6 or less.

[0093] (8) The separation membrane structure according to (7) above, wherein the average thickness T1 is 1 μm or less.

[0094] (9) The separation membrane structure according to (7) or (8) above, wherein the average thickness T2 is 0.5 μm or more and 10 μm or less.

[0095] (10) In the separation membrane structure according to any one of (1) to (9) above, the substance having the pores is a zeolite, a metal-organic framework, a metal oxide, a metal nitride, or a mixture thereof.

[0096] (11) A method for producing a separation membrane structure, comprising the steps of preparing a powder containing a substance having pores and a porous support, and spraying the powder onto one side of the porous support to form the separation membrane on the one side, thereby obtaining the separation membrane structure, wherein the surface roughness (arithmetic mean roughness Ra) of the separation membrane on the side opposite the porous support is 1.3 μm or less, and the surface roughness (maximum height roughness Rz) of the separation membrane on the opposite side is 10 μm or less.

[0097] (12) In the method for producing a separation membrane structure according to (11) above, in the step of obtaining the separation membrane structure, the powder is sprayed onto the one surface of the porous support by an aerosol deposition method.

[0098] As described above, various embodiments according to the present disclosure have been described. However, these are presented as examples and do not limit the scope of the invention in any way. The novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are within the scope and spirit of the invention, and are also encompassed by the inventions described in the claims and their equivalents. For example, one or more layers having any desired function may be provided between the porous support 2 and the separation membrane 3. Such functions preferably include, for example, a function to enhance adhesion between the porous support 2 and the separation membrane 3, a function to prevent a sudden change in the average pore size at the boundary between the porous support 2 and the separation membrane 3, a function to relieve stress between the porous support 2 and the separation membrane 3, and a function to enhance the selectivity of the molecules to be separated.

[0099] [Examples] The present disclosure will be described in more detail below with reference to examples, but the present disclosure is not limited to these examples.

[0100] 1. Preparation of Membrane Structure (Example 1) Preparation of Porous Support A porous alumina tube was cut to a length of 50 mm, washed with ion-exchanged water and ethanol in that order, and then dried before use. The porous alumina tube had an outer diameter of 12 mm, an inner diameter of 9 mm, and an average pore diameter of 1.2 μm.

[0101] Preparation of powder P for aerosol deposition method 2 g of zeolite (LTA type) with an average particle size of 50 nm as the first particles and 2 g of titanium oxide (TiO ２98 g of ethanol (99.5% by mass) and 60 g of ethanol (99.5% by mass) were placed in a container and kneaded using a planetary mixer. Kneading was performed for 2 minutes at a revolution speed of 2,000 rpm and a rotation speed of 800 rpm. The slurry obtained after kneading was left at 70°C for 3 hours and then left at 100°C for 1 hour to dry. The dried product obtained by drying was pulverized in a blade mill at 20,000 rpm for 1 minute. This resulted in a powder. In other words, the particle mixing ratio in the powder was 2%.

[0102] Formation of a membrane on one surface of a porous support The membrane was formed using a membrane structure manufacturing apparatus 4 shown in Figure 6. First, the porous support was set on a support rod 61 of a support mechanism 6 that supports the porous support rotatably around its central axis. Next, the powder was sprayed onto the outer peripheral surface (one surface) of the porous support at approximately 20°C.

[0103] Specifically, the powder P to be sprayed was loaded into the aerosol generator 75, and the chamber 5 containing the porous support was depressurized to 5 Pa by the pump 81. In this state, the powder P was sprayed onto the porous support while it was rotating from the nozzle 71 having a rectangular nozzle 711 measuring 10 mm x 0.5 mm in plan view. While the powder was being sprayed, the pressure inside the chamber 5 was adjusted to be approximately 150 Pa or more and 200 Pa or less. The width W of the nozzle 711, which is the length along the radial direction of the porous support, was 10 mm. In other words, W / R was 0.83.

[0104] At this time, nitrogen gas (N ２) was used, and this nitrogen gas was supplied from a gas cylinder 72 to an aerosol generator 75 filled with powder, thereby dispersing the powder P in the nitrogen gas to generate an aerosol. The flow rate of the nitrogen gas was adjusted by a mass flow controller 74 installed upstream of the aerosol generator 75. The mass flow controller 74 also adjusted the amount of nitrogen gas supplied so that the pressure inside the aerosol generator 75 was 50 Pa. The aerosol was then ejected from a nozzle 71 toward the porous support to form a film. The ejection speed of the aerosol from the nozzle 71 was 250 mm / sec, and the distance from the nozzle 71 to one surface of the porous support was 10 mm. The rotation speed around the central axis of the porous support was 5 rpm, and the movement speed of the nozzle 71 along the central axis of the porous support was 5 cm / sec. The number of scans was 12. The number of scans refers to the number of times the tip of the nozzle 71 (the nozzle 711) passed through a position facing the same point on one surface of the porous support. In this manner, the membrane structure according to Example 1 was obtained.

[0105] Examples 2 to 8 Film structures were produced in the same manner as in Example 1, except that the constituent materials and particle sizes of the first particles and second particles were changed as shown in Table 2.

[0106] Comparative Example 1 A porous support was prepared in the same manner as in Example 1. Zeolite powder (LTA type) having an average particle size of 300 nm was prepared as the first particles. Approximately 3 g of the zeolite powder (LTA type) was rubbed by hand onto the outer peripheral surface (one side) of the porous support to adhere it as seed crystals.

[0107] 3.2 g of sodium hydroxide was added to 18 g of water and stirred to obtain an aqueous sodium hydroxide solution. 4.3 g of aluminum hydroxide was added to the aqueous sodium hydroxide solution and stirred at 80°C for 1 hour to dissolve. 23.8 g of a 22% by mass aqueous sodium silicate solution was added to 23.8 g of water and stirred at 50°C for 1 hour. These two aqueous solutions were mixed and stirred at room temperature for 1 hour to obtain an aluminosilicate solution.

[0108] The porous support with the attached seed crystals was immersed vertically in the aluminosilicate liquid and allowed to stand for 5 hours at 80° C. Thereafter, the porous support with the membrane formed thereon was taken out, washed with water, and then dried overnight at 100° C. to obtain a membrane structure.

[0109] Comparative Example 2 A membrane structure was produced in the same manner as in Comparative Example 1, except that the first particles were attached to the porous support as seed crystals by the following procedure (dip coating method). Zeolite powder (LTA type) with an average particle size of 300 nm as the first particles was dispersed in water to a concentration of 0.5 g / mL to prepare a dip coating solution. The porous support was immersed vertically in the dip coating solution for 1 hour, and then dried at 100°C for 2 hours, thereby attaching the first particles to the porous support as seed crystals.

[0110] 2. Measurement and Test [Measurement of film surface roughness (arithmetic mean roughness Ra), surface roughness (maximum height roughness Rz), and average length RSm of roughness curve element] Using a surface profiler conforming to JIS B0651:2001 (ISO3274:1996), the surface roughness (arithmetic mean roughness Ra), surface roughness (maximum height roughness Rz), and average length RSm of roughness curve element of the outermost surface of the film were measured according to the following procedure in accordance with JIS B0601:2013 (ISO4287:1997). The measurement needle of the surface profiler (manufactured by Tokyo Seimitsu Co., Ltd., "SURFCOM130A") was placed in contact with the outermost surface of the film, and the needle was swept 1 cm to measure the surface roughness (arithmetic mean roughness Ra), surface roughness (maximum height roughness Rz), and average length RSm of the roughness curve element. The arithmetic average of the measurement results at three different locations on the outermost surface was obtained as the surface roughness (arithmetic mean roughness Ra), surface roughness (maximum height roughness Rz), and average length RSm of the roughness curve element for each Example and Comparative Example.

[0111] [Acetic Acid Immersion Test] The membrane structure was immersed in a 50% by mass aqueous solution of acetic acid at 80°C for 300 hours, washed with ion-exchanged water, and left (dried) overnight at 70°C. Thereafter, the arithmetic mean of the surface roughness (arithmetic mean roughness Ra) of the outermost surface of the membrane structure was measured as "Ra after immersion" in the same manner as described above. Then, the ratio of the arithmetic mean of the Ra after immersion to the arithmetic mean of the surface roughness (arithmetic mean roughness Ra) of the membrane structure that had not been subjected to the acetic acid immersion test (i.e., before immersion) was obtained as the "Ra change rate."

[0112] [Obtaining the area ratio of the second particle region] The cross-sectional microstructure of the film was observed using a scanning electron microscope (SEM). Based on the color density of the cross-sectional image of the film at any point in the in-plane direction, the area ratio of the region composed of components derived from the second particles (hereinafter also referred to as the second particle region) to the cross-sectional area of ​​the film was measured. The second particle region appeared lighter in color than the region composed of components derived from the first particles. Note that this measurement was carried out after confirming by observation using the SEM-EDX method that the region that appeared lighter in color was the second particle region. In the measurement, one cross-sectional image in the range of 1 μm in the thickness direction × 10 μm in the in-plane direction was used.

[0113] [Measuring the average thickness of the membrane] The average thicknesses T1 and T2 [μm] of the first and second portions of the membrane were measured at five locations on the cross section of the membrane structure and calculated by arithmetically averaging the measured thicknesses. The five locations were selected to be at least 20 μm apart in the in-plane direction of the membrane. Furthermore, when measuring at each location, the thickness of the first portion and the thickness of the second portion were measured so that they were aligned on the same line in the thickness direction of the membrane (membrane structure). The first portion refers to the portion of the membrane that penetrates the porous support, and the second portion refers to the portion of the membrane excluding the first portion.

[0114] When the interface between the porous support and the membrane, which is the boundary between the first and second parts, could be identified by observation using a scanning electron microscope (SEM) (Examples 5 and 6), the thickness was measured based on that interface.

[0115] In cases where the interface between the porous support and the membrane could not be clearly identified by SEM observation (Examples 1-4, 7-8, Comparative Examples 1-2), elemental analysis was performed on the measurement area using a scanning electron microscope (SEM)-energy dispersive X-ray spectroscopy (EDX). The measurement area was set to 10 μm along the in-plane direction of the membrane structure and 1 μm along the thickness direction of the membrane structure in the microstructural observation of the cross section of the membrane structure. Then, at each of the five locations where the thickness of the first portion and the thickness of the second portion were measured, the measurement area was moved from the outermost surface of the membrane toward the porous support. At this time, the measurement areas before and after each movement were moved so as not to overlap with each other. Then, a graph of each component detected by elemental analysis was created, and the location where the composition of the most frequently detected component changed was identified as the interface between the porous support and the membrane. Then, thickness measurements were performed based on the interface.

[0116] [Selective Water Permeation Separation Test] A test was conducted to selectively permeate and separate water from a 50°C water / ethanol aqueous solution (10 / 90 mass%), which was a liquid to be separated (mixed fluid), by a pervaporation method. Specifically, the test was conducted using a water permeation separation test device 1000 shown in Figure 10. Figure 10 is a schematic diagram showing the water permeation separation test device.

[0117] A test container 1001 was filled with a liquid to be separated 1002, and the outer peripheral surface of the test container 1001 was heated by a heater 1003 so that the liquid to be separated 1002 reached 50° C. The membrane structures 1′ of the examples and comparative examples were placed in the test container 1001 filled with the liquid to be separated 1002, and the outer peripheral surface (one side) was brought into contact with the liquid to be separated 1002.

[0118] The pressure in the cavity of the membrane structure 1' was reduced by a vacuum pump 1008 so that the pressure in the cavity was 200 Pa or less. The pressure in the cavity was monitored using a pressure gauge 1007. A pressure difference was generated between the cavity and the outer peripheral surface (one side) with which the liquid to be separated 1002 was in contact, and this pressure difference caused the water molecules to be separated in the liquid to be separated 1002 to permeate and vaporize through the membrane structure 1'. At this time, the permeation of the water molecules causes a concentration gradient in the liquid to be separated 1002 near the outermost surface of the membrane (the outer peripheral surface of the membrane structure) (the water concentration is low near the outermost surface), but the test was performed while stirring the liquid to be separated 1002 with a stirrer 1004 and a stirrer bar 1005, so that the concentration gradient was quickly eliminated.

[0119] The water molecules that permeated the membrane structure 1' passed through the liquid sending pipe 1006 and were collected as permeated liquid in the permeated liquid collecting trap 1009. Two permeated liquid collecting traps 1009 were provided, and the permeated liquid collecting traps 1009 were switched using valves V1 to V4. After 60 minutes had elapsed since the start of depressurization, the permeated amount (g / m) was calculated from the weight of the liquid collected in the permeated liquid collecting trap 1009. ２ The water content of the collected liquid was then calculated using the Karl Fischer method.

[0120] 3. Results The measurement results of Examples 1 to 8 and Comparative Examples 1 and 2 are summarized in Tables 2 and 3 below.

[0121]

[0122]

[0123] As shown in Table 3, in each Example, a separation membrane structure with a small outermost surface roughness (arithmetic mean roughness Ra, maximum height roughness Rz) was produced. The separation membrane structure of each Example exhibited sufficient permeation rate and high separation performance. Furthermore, in the separation membrane structure of each Example, the penetration of the membrane into the porous support (average thickness T1 / average thickness T2) was suppressed to a small value. Furthermore, in Examples 7 and 8, the change in the separation membrane structure before and after immersion in acetic acid was extremely small, and high acid resistance and water resistance were exhibited. Furthermore, in Examples 7 and 8, no damage such as membrane peeling was observed. On the other hand, in Examples 1 to 4, it was confirmed that some membrane components were floating in the acetic acid aqueous solution after immersion. However, sufficient resistance to the acetic acid aqueous solution (i.e., acid resistance and water resistance) was also confirmed in Examples 1 to 6.

[0124] DESCRIPTION OF SYMBOLS 1: Separation membrane structure, 2: Porous support, 20: Particle, 21: Surface, 3: Separation membrane, 31: First portion, 32: Second portion, 321: Outermost surface, 3a: Particle, 3a': Particle-derived component, 3b: Second particle, 3b': Second particle-derived component, 4: Manufacturing apparatus, 5: Chamber, 6: Support mechanism, 61: Support rod, 62: Motor, 7: Spout mechanism, 71: Nozzle, 711: Spout, 72: Gas cylinder, 73: Transfer pipe, 74: Mass flow controller, 75: Aerosol generator, 78: Movement mechanism, 8: Pressure reduction mechanism, 81 : Pump, 9: Control means, 91: Calculation unit, 92: Memory unit, 100: Separation device, 200: Housing, 201: Internal space, 1000: Water permeation separation test device, 1001: Test vessel, 1002: Liquid to be separated, 1003: Heater, 1004: Stirrer, 1005: Stirrer bar, 1006: Liquid delivery pipe, 1007: Pressure gauge, 1008: Vacuum pump, 1009: Trap for collecting permeated liquid, P: Powder, T1: Average thickness, T2: Average thickness, V1: Valve, V2: Valve, V3: Valve, V4: Valve

Claims

1. A separation membrane structure comprising a porous support and a separation membrane, wherein the separation membrane is provided on one side of the porous support and contains a substance having pores or a component derived from a substance having pores, and wherein the surface of the separation membrane opposite the porous support has a surface roughness (arithmetic mean roughness Ra) of 1.3 μm or less, and the surface of the separation membrane opposite the porous support has a surface roughness (maximum height roughness Rz) of 10 μm or less.

2. A separation membrane structure according to claim 1, wherein the surface roughness (arithmetic mean roughness Ra) of the opposite surface of the separation membrane is 0.1 μm or more.

3. A separation membrane structure according to claim 1 or 2, wherein the average length RSm of the roughness curve elements on the opposite surface of the separation membrane is 5 μm or more and 60 μm or less.

4. A separation membrane structure according to any one of claims 1 to 3, wherein the ratio of the surface roughness (arithmetic mean roughness Ra) of the opposite surface after immersion in a 50 mass % acetic acid aqueous solution at 80°C for 300 hours to the surface roughness (arithmetic mean roughness Ra) of the opposite surface before immersion in the acetic acid aqueous solution is 0.5 or more and 2 or less.

5. A separation membrane structure according to any one of claims 1 to 4, wherein the surface roughness (maximum height roughness Rz) of the opposite surface of the separation membrane is 1 μm or more.

6. A separation membrane structure according to any one of claims 1 to 5, wherein the substance having the pores is crystalline.

7. A separation membrane structure according to any one of claims 1 to 6, wherein when the average thickness of a first portion of the separation membrane embedded in the porous support is T1 [μm] and the average thickness of a second portion of the separation membrane excluding the first portion is T2 [μm], T1 / T2 is 1 / 6 or less.

8. A separation membrane structure according to claim 7, wherein the average thickness T1 is 1 μm or less.

9. A separation membrane structure according to claim 7 or 8, wherein the average thickness T2 is 0.5 μm or more and 10 μm or less.

10. The separation membrane structure according to any one of claims 1 to 9, wherein the substance having pores is a zeolite, a metal-organic framework, a metal oxide, a metal nitride, or a mixture thereof.

11. A method for manufacturing a separation membrane structure, comprising the steps of: preparing a powder containing a substance having pores and a porous support; and spraying the powder onto one surface of the porous support to form the separation membrane on the one surface, thereby obtaining the separation membrane structure, wherein the surface of the separation membrane opposite the porous support has a surface roughness (arithmetic mean roughness Ra) of 1.3 μm or less, and the surface roughness of the opposite surface of the separation membrane (maximum height roughness Rz) of 10 μm or less.

12. A method for producing a separation membrane structure according to claim 11, wherein in the step of obtaining the separation membrane structure, the powder is sprayed onto the one surface of the porous support by an aerosol deposition method.

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