Porous body, composite porous body, fluid separation membrane module, fluid separation method, and gas separation apparatus

Abstract

To provide a porous body, a composite porous body, a fluid separation membrane module, a fluid separation method, and a gas separation apparatus that improve mechanical properties, prevent damage during transport and use, and exhibit stable performance over a long period of time.SOLUTION: A porous body is composed of particles with an aspect ratio of 10 to 10,000.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a porous body, a composite porous body, a fluid separation membrane module, a fluid separation method, and a gas separation apparatus. [Background technology]

[0002] Porous bodies composed of particles have excellent properties such as adsorption, separation, high permeability, etc., and therefore have been developed for various applications such as adsorbents, separation membranes, sound absorbing materials, filters, etc. However, due to the high porosity of porous bodies, the mechanical properties can be an issue depending on the application, and a technique of using a binder together with the particles is known (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2012-57260 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, it was difficult to industrially produce a satisfactory level of the technology described in Patent Document 1. Patent Document 1 discloses a method for preparing a spinning dope for forming a porous ceramic hollow fiber membrane, which is characterized by dispersing or dissolving a ceramic powder and a membrane-forming polymeric substance separately in a water-soluble aprotic polar solvent, and mixing the obtained ceramic powder dispersion and the membrane-forming polymeric substance solution before spinning to prepare a spinning dope. This is an excellent method for obtaining a porous body using ceramic powder, but on the other hand, there are problems with the mechanical properties, especially flexibility, and the hard and low-elongation porous body is often damaged during transportation or use, causing a change in macroscopic form and losing its function.

[0005] Therefore, an object of the present invention is to provide a porous body, a composite porous body, a fluid separation membrane module, a fluid separation method, and a gas separation apparatus, all of which have excellent mechanical properties. [Means for solving the problem]

[0006] In order to solve the above problems, the present invention has the following features: That is, the present invention is a porous body characterized by being composed of particles having an aspect ratio of 10 to 10,000. Effect of the Invention

[0007] The present invention can provide a porous body, a composite porous body, a fluid separation membrane module, a fluid separation method, and a gas separation apparatus that are composed of particles with an aspect ratio of 10 to 10,000, thereby improving mechanical properties, preventing damage during transportation or use, and providing stable functionality for a long period of time. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] The present invention will be described below with reference to examples, but the present invention should not be construed as being limited to these examples.

[0009] The porous body of the present invention is composed of particles having an aspect ratio of 10 to 10,000.

[0010] The aspect ratio is defined as the value obtained by dividing the longest axis by the shortest axis among the shortest axis of the shortest axis, the shortest axis, and the longest axis of the shortest axis among the shortest axis, the shortest axis, and the longest axis of the shortest axis. There is no particular limitation on the method of obtaining three-dimensional data of a particle, but examples of the method include a method of obtaining three-dimensional data by applying a CT method to a transmission microscope using a probe such as an X-ray, an electron beam, or a visible light, and a method of obtaining three-dimensional data by repeatedly cutting and observing the cut surface with a focused ion beam or the like. These methods are appropriately selected according to the size and aspect ratio of a certain particle, and a method that can observe and obtain the entire particle as three-dimensional data. In this case, even if a single particle is in a bent state, the aspect ratio is calculated by performing an ellipsoid approximation while maintaining its shape.

[0011] The higher the aspect ratio of the particles having an aspect ratio of 10 to 10,000 contained in the porous body of the present invention, the lower the bending moment of the particles themselves, and the greater the effect of improving flexibility. In addition, the lower the aspect ratio, the shorter the relaxation time of the particles compared to the same particle diameter, making it easier to form a uniform porous body. From these points of view, it is preferable that the particles have an aspect ratio of 100 to 5,000, and more preferably that the particles have an aspect ratio of 200 to 5,000.

[0012] The average aspect ratio of the particle aggregate constituting the porous body is obtained by randomly extracting 10 particles, calculating the aspect ratio of each of them using the above-mentioned method, and excluding the maximum and minimum aspect ratios, and then taking the arithmetic average. The higher the average aspect ratio, the lower the bending moment of the particle aggregate, and the greater the effect of improving flexibility. In addition, the lower the average aspect ratio, the shorter the relaxation time of the particle aggregate compared to the same particle diameter, making it easier to form a uniform porous body. From these points of view, the average aspect ratio is preferably in the range of 100 to 5,000, and more preferably in the range of 200 to 5,000.

[0013] In addition, the ratio of the minor axis 1 to the minor axis 2 (hereinafter, axial ratio) of the ellipsoid approximated to the particle is preferably in the range of 1.0 to 20, after rearranging the relationship of minor axis 1 ≧ minor axis 2. The closer the axial ratio is to 1, the closer the particle shape is to a fiber shape, there is no distribution of bending moment in the formation direction of minor axis 1 and minor axis 2, the anisotropy of the porous body to bending can be reduced, and the characteristics become isotropic. In addition, the higher the axial ratio, the more anisotropic the distribution of bending moment becomes, so the response of the porous body to bending becomes anisotropic. It is preferable that these characteristics are appropriately selected according to the application, but the axial ratio in the case of imparting isotropic characteristics to the porous body is preferably in the range of 1.0 to 5.0. In addition, the axial ratio in the case of imparting anisotropic characteristics to the porous body is preferably in the range of 5.0 to 20. In addition, it is also preferable to mix and use a plurality of particles having different axial ratios for the purpose of controlling isotropic and anisotropic characteristics.

[0014] The average particle size of the particles is not particularly limited as long as it is possible to form a porous body, but the smaller the average particle size, the smaller the pore diameter formed in the porous body, and the more the surface smoothness is improved. In addition, the larger the average particle size, the easier it is to form a large porous body. In addition to the above viewpoints, it is preferable to appropriately select according to the application of the porous body, but in particular, when the application range of the porous body is assumed to be application as a separation membrane support for separating fluids, it is preferable that the average particle size of the particles is in the range of 0.05 to 100 μm, since it is possible to achieve both pore diameter, moldability, and surface smoothness. It is more preferable that the average particle size is in the range of 0.05 to 10 μm. The average particle size of the particles referred to here is calculated based on the diameter of the sphere calculated by calculating the sphere corresponding to the volume of the approximate ellipsoid for which the aspect ratio was calculated above. The volume V of the approximate ellipsoid is calculated by V=(4 / 3)×π×a×b×c, where the major axis of the ellipsoid is a, the minor axis 1 is b, and the minor axis 2 is c. The average particle size is calculated by randomly selecting 10 particles, calculating their particle sizes using the method described above, excluding the maximum and minimum particle sizes, and then taking the arithmetic average, as in the case of calculating the aspect ratio above.

[0015] The particles having an aspect ratio of 10 to 10,000 of the present invention can be appropriately used from those known in the art, but examples include fibrous, film-like, and disk-like shapes, and in particular, those having a fibrous or film-like shape are preferred because the aspect ratio can be easily adjusted. In particular, the use of those having a fibrous shape is preferred because it is easier to control the shape and mechanical properties of the porous body due to the synergistic effect with the component that connects the particles having an aspect ratio of 10 to 10,000 described below. In addition, the constituent material can be a known material, and any material such as a biological material, polymer, ceramic, carbon, or metal can be selected. When the porous body is to be made flexible, it is preferable to select a polymer. When the porous body is to be made heat-resistant, it is preferable to select ceramic, carbon, or metal. When the porous body is to be made conductive, it is preferable to select carbon or metal. From the viewpoint of achieving both flexibility and structural stability, which are the mechanical properties of the porous body, it is particularly preferable to select carbon.

[0016] The particles having an aspect ratio of 10 to 10,000 of the present invention may be any particles that satisfy the above-mentioned viewpoints, and examples thereof include graphene, carbon nanotubes, cellulose nanofibers, graphite, mica, talc, montmorillonite, whiskers, etc., and are preferably selected from graphene, carbon nanotubes, cellulose nanofibers, talc, montmorillonite, and whiskers, and more preferably graphene and carbon nanotubes are selected. Note that, as long as the objectives and effects of the present invention are achieved, the particles may contain components other than the particles having an aspect ratio of 10 to 10,000 of the present invention.

[0017] It is also preferable to have a component that connects at least a part of the particles having an aspect ratio of 10 to 10,000. The component that connects at least a part of the particles having an aspect ratio of 10 to 10,000 is a component that has an interaction such as adhesiveness with the particles and connects a certain particle to another particle to form a porous body. The connecting component is not particularly limited as long as it has the above function, and any material such as a biological material, a polymer material, a ceramic, a carbon material, or a metal can be selected. Here, when the constituent material of the particles having an aspect ratio of 10 to 10,000 and the constituent material of the connecting component are selected from the same material, the interaction between the particle and the connecting component is stronger than when different constituent materials are selected, so that even when an external stress is applied to the particle and the connecting component, peeling is suppressed and the shape of the porous body is maintained, and a porous body with excellent mechanical properties is obtained, which is preferable.

[0018] As for the constituent material of the connecting component, if the porous body is to have flexibility, it is preferable to select a polymer material. Furthermore, if the porous body is to have heat resistance, it is preferable to select a ceramic, carbon material, or metal. Furthermore, if the porous body is to have conductivity, it is preferable to select a carbon material or metal. From the viewpoint of achieving both flexibility, which is the mechanical property of the porous body, and structural stability, it is particularly preferable to select a carbon material. It is preferable that the constituent materials of the component connecting to the particle are both mainly carbon, since this provides an excellent balance between mechanical properties and durability such as heat resistance.

[0019] When the component connecting at least a part of the particles having an aspect ratio of 10 to 10,000 is made of a carbon material, the component connecting at least a part of the particles having an aspect ratio of 10 to 10,000 preferably contains 90 to 99.5 atomic % of carbon atoms. The ratio of carbon atoms is measured by energy dispersive X-ray spectroscopy (EDX) analysis combined with an electron microscope, in which 10 points of the component connecting the particles are randomly selected, the ratio of carbon atoms at each point is calculated, and the data of the maximum and minimum points is deleted to obtain an average value. Here, the ratio of carbon atoms is defined as the ratio of carbon atoms among the calculated composition ratio of all atoms detectable by EDX. The higher the ratio of carbon atoms, the higher the mechanical properties and durability of the pure carbon material can be maintained, and the lower the ratio of carbon atoms, the more preferable it is because it can have an interaction with other materials and improve adhesion. From these viewpoints, the ratio of carbon atoms is preferably in the range of 95 to 99.5 atomic %, and more preferably in the range of 98 to 99 atomic %.

[0020] The volume ratio of the particles having an aspect ratio of 10 to 10,000 constituting the porous body of the present invention to the components connecting at least a portion of the particles having an aspect ratio of 10 to 10,000, calculated as (particle volume) / (connecting component volume), is preferably in the range of 0.02 to 30, from the viewpoint that the particles constituting the porous body are sufficiently integrated by the connecting components.

[0021] The porous body of the present invention preferably has a porosity in the range of 10 to 95%. A higher porosity is preferable from the viewpoint of reducing the permeation resistance of fluids such as gases and liquids, while a lower porosity is preferable from the viewpoint of suppressing destruction against externally applied forces such as bending and compression in view of the mechanical properties of the porous body. From these viewpoints, the porosity is preferably 30 to 90%, and more preferably in the range of 40 to 70%.

[0022] The shape of the porous body of the present invention is not particularly limited, and it can be any shape such as fiber, tube, film, bulk, etc. The porous body of the present invention is preferably a fiber or film having an aspect ratio of 10 to 30,000. More preferably, it is a fiber or film having an aspect ratio of 100 to 30,000.

[0023] When the porous body is a fibrous porous fiber, the higher the aspect ratio, the higher the flexibility of the porous fiber against bending is, and the lower the aspect ratio, the higher the rigidity of the porous fiber against bending is. From these viewpoints, the aspect ratio of the porous fiber is preferably in the range of 20 to 20,000, and more preferably in the range of 30 to 18,000.

[0024] In addition, when the porous body is in the form of a film, the higher the aspect ratio, the more flexible the porous body can be when bent, and the lower the aspect ratio, the more rigid the porous body can be when bent. From these viewpoints, the aspect ratio of the porous body in the form of a film is preferably in the range of 20 to 20,000, and more preferably in the range of 30 to 18,000.

[0025] The porous body of the present invention is more preferably in the form of fibers having an aspect ratio of 10 to 30,000.

[0026] One of the preferred embodiments of the porous body of the present invention, the porous fiber, is not particularly limited with respect to its cross-sectional shape, and examples thereof include a circular cross-section, a polygon such as a triangle, a flat or multi-lobed cross-section, and a hollow cross-section. These shapes are preferably appropriately selected according to the use and purpose of the porous fiber. However, when the porous fiber is used as a support for a gas separation membrane, the cross-sectional shape is preferably a hollow cross-section. That is, it is preferable that the porous body of the present invention is in the form of hollow fibers. The hollow cross-section has one or more holes forming a hollow portion in the cross-section. When the diameter d of the hole is in the range of 0.02 < d / D < 0.90 with respect to the average diameter D of the porous fiber, it is possible to suppress damage due to the external force received from the gas to be separated, which is the object of separation received by the porous fiber when used as a support for the gas separation membrane, while reducing the pressure loss in the hollow portion, and from the viewpoint of maximizing the performance as a gas separation membrane, it is preferable. From these viewpoints, the ratio of the diameter d of the hole to the average diameter D of the porous fiber, and the hollow portion ratio are preferably 0.30 < d / D < 0.70. In particular, when the cross-sectional shape has two or more hollow portions in the cross-section of the porous fiber, the hollow portion ratio in the range of 0.05 < d / D < 0.30 is preferable from the viewpoint of suppressing damage due to the external force received from the gas while reducing the pressure loss in the hollow portion.

[0027] One of the preferred embodiments of the porous body of the present invention, the porous fiber, preferably has an outer diameter in the range of 0.1 to 15 mm because it has an excellent balance of mechanical properties. The larger the outer diameter, the higher the strength of the porous fiber as seen macroscopically, and it is particularly preferable from the viewpoint of suppressing breakage against the tensile stress in the fiber axis direction. Also, the smaller the outer diameter, the lower the bending rigidity of the porous fiber as seen macroscopically, and it is preferable from the viewpoint of suppressing breakage when subjected to bending deformation. The outer diameter is preferably 0.2 to 10 mm from the above viewpoints, and more preferably 0.2 to 1.0 mm.

[0028] It is also preferable to form a thin film having a thickness of 0.1 to 10 μm on the surface of the porous body of the present invention. That is, it is also preferable to adopt a composite porous body characterized by forming a thin film having a thickness of 0.1 to 10 μm on the surface of the porous body of the present invention. The function of the thin film can be assumed to be various and can be used in combination, such as controlling the diffusion and flow of fluid into the composite porous body, transmitting stress to particles constituting the composite porous body, imparting a fluid separation function by the thin film, and imparting electrical conductivity and thermal conductivity. In particular, when the thin film is imparted with a fluid separation function, that is, when the composite porous body is in the form of a porous body and a thin film, the mechanical properties of the porous body of the present invention can be maximized, breakage of the composite porous body during transportation or use can be suppressed, and stable long-term performance can be exhibited, which is preferable. The thin film constituting the composite porous body, which is a preferred embodiment of the present invention, is not particularly limited as long as it has a fluid separation function, and various materials can be used, including zeolite, polymer materials, carbon materials, and silicones. Among them, it is preferable to select a carbon material from the viewpoint of the fluid separation function as a thin film, heat resistance, and film formability. The carbon material constituting the thin film preferably has a carbon atom ratio of 90 to 99.5 atomic %. The higher the carbon atom ratio of the carbon material constituting the thin film, the easier it is to form fine pores in the thin film composed of carbon atoms, and the better the balance between heat resistance and fluid permeation and separation characteristics, while the lower the carbon atom ratio, the more preferable it is from the viewpoint of enabling control of the dissolution and diffusibility of the fluid by utilizing the interaction between the thin film and the fluid.

[0029] In addition, the fluid separation membrane module containing a plurality of composite porous bodies of the present invention is preferable because it can function as a device for efficiently contacting and separating fluids with the composite porous bodies. The fluid separation membrane module is composed of a composite porous body, an adhesive, a sealant, and a case for containing the composite porous bodies, and may also contain a plurality of other members that separate fluids as a fluid separation membrane module while controlling the flow of fluids before and after separation and that have materials suitable for the environment in which the fluid separation membrane module is used, such as heat resistance and chemical resistance.

[0030] The fluid separation membrane module is preferably provided with at least one port for introducing a fluid containing two or more components to be separated, a portion for contacting the composite porous body, a port for introducing a flow that increases the concentration of a specific component, and a port for introducing a flow that decreases the concentration. With the fluid separation membrane module having the above configuration, a fluid containing two or more components to be separated can be efficiently separated into a flow that increases the concentration of a specific component and a flow that decreases the concentration. That is, the fluid separation method of the present invention is a fluid separation method using the fluid separation membrane module of the present invention, in which a fluid containing two or more components is supplied to the fluid separation membrane module, and at least one flow that increases the concentration of one component in the fluid and one flow that decreases the concentration of one component in the fluid are provided.

[0031] The fluid separation membrane module is also suitable for use as a gas separation device that uses the fluid separation membrane module as a component. The gas separation device includes a line for supplying a mixed gas to the fluid separation membrane module, and respective discharge lines for the non-permeating gas that does not permeate the fluid separation membrane and the permeating gas that permeates the fluid separation membrane from the supplied mixed gas. In addition, it is also preferable to provide an appropriate pressure difference between the non-permeating side and the permeating side of the fluid separation membrane by appropriately providing a compressor for applying pressure to the mixed gas or a vacuum pump for reducing the pressure conversely. Furthermore, when the temperatures of the mixed gas, permeating gas, and non-permeating gas need to be controlled, it is also preferable to have a mechanism for heating and cooling them, respectively. EXAMPLES

[0032] The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited thereto. Evaluations in each of the examples and comparative examples were carried out by the following methods.

[0033] <particle> (Aspect Ratio) A porous material was used as an observation sample, and a cross section of the observation sample was cut to a thickness of 10 nm using a focused ion beam. The cut surface was observed and photographed using an electron microscope, and this process was repeated to obtain three-dimensional data consisting of particles, connecting components, and voids. Ten particles of interest were randomly selected from the obtained three-dimensional data, and each particle was approximated by the least squares method to form the most closely circumscribed ellipsoid. The aspect ratio was calculated by dividing the longest axis by the shortest axis of the shortest axis among the shortest axis, shortest axis 1, shortest axis 2, and longest axis 1 that constitute the ellipsoid obtained by the approximation. Ten individual particles were randomly selected, and their aspect ratios were calculated using the method described above. The maximum and minimum aspect ratios were excluded, and the average aspect ratio was calculated by taking the arithmetic mean and rounding off to the nearest tenth place.

[0034] (ratio of minor axis 1 / minor axis 2) In the ellipsoid obtained when calculating the aspect ratio, the relationship was rearranged to be minor axis 1≧minor axis 2, and the aspect ratio was calculated as the ratio of minor axis 1 / minor axis 2.

[0035] (Average particle size) The average particle size is calculated by calculating the sphere that corresponds to the volume of the approximate ellipsoid for which the aspect ratio was calculated above, and then based on the diameter of that sphere. The volume V of the approximate ellipsoid is calculated by V = (4 / 3) x π x a x b x c, where the major axis of the ellipsoid is a, the minor axis 1 is b, and the minor axis 2 is c. The average particle size is calculated by randomly selecting 10 particles, as in the case of calculating the aspect ratio above, calculating the particle size of each using the method described above, and then excluding the maximum and minimum particle sizes, and taking the arithmetic mean.

[0036] (proportion of carbon atoms) Energy dispersive X-ray spectroscopy was applied to the ion beam cut cross section used to measure the aspect ratio, and the ratio of carbon atoms at 10 randomly selected measurement points on the particle was calculated as a percentage. After excluding the maximum and minimum ratios of carbon atoms at these two points, the arithmetic average was calculated.

[0037] <Connecting components> (ratio of carbon atoms in connecting components) As with the ratio of carbon atoms in the <particles>, the components connecting particles having an aspect ratio of 10 to 10,000 were measured.

[0038] <Porous body> (Aspect Ratio) The aspect ratio of a porous body was determined by calculating the length d of the shortest part of the porous body and the length e of the longest part of the porous body based on the magnification of the microscope and a scale calibrated for that magnification, and calculating e / d as the aspect ratio of the porous body. Note that, when observing the longest part by microscope, if the observation sample does not fit inside the microscope, the entire length was measured separately and e was calculated.

[0039] (Outer diameter, length) When the porous body has a fibrous form, 10 randomly selected cross sections perpendicular to the fiber axis of the porous body were observed under a microscope, the circumscribing circles were drawn, and the diameters of the circles were calculated. The arithmetic mean of the obtained circle diameters was calculated excluding the maximum and minimum diameters to determine the outer diameter of the fibrous porous body. The length of the porous body can be measured using a microscope, micrometer, caliper, tape measure, etc., depending on the length range, and a reasonable method was selected according to the measurable range of each measuring device and the length of the porous body to measure one sample of the fibrous porous body.

[0040] (particle volume ratio) The volume of the particle portion and the volume of the connecting component were calculated from the three-dimensional data obtained when the aspect ratio was measured, and the volume of the particle portion was divided by the volume of the connecting component to calculate the particle volume ratio.

[0041] (Number of hollows) When the porous body of the present invention has a hollow fiber morphology, 10 randomly selected cross sections perpendicular to the fiber axis of the porous body were observed under a microscope, and the number of independent voids in the cross section where there were no particles having an aspect ratio of 10 to 10,000 that constitute the porous body and no components connecting the particles having an aspect ratio of 10 to 10,000 were counted, and this was regarded as the number of hollows.

[0042] (Hollow diameter, ratio) According to the method for counting the number of hollows, the cross-sectional area of ​​the voids that make up the hollows was calculated, and the diameter d of the circle corresponding to that cross-sectional area was taken as the diameter of the hollows. The outer diameter of the porous body was taken as D, and the hollow ratio d / D was calculated using the diameter d of the circle. The diameter d of the circle and the hollow ratio were calculated for 10 samples randomly extracted, and the maximum and minimum points were excluded, and the data was calculated by arithmetic averaging.

[0043] (Transportation durability) Random vibration conforming to the random vibration test of JIS Z0200:2023 was applied to ten 100 mm porous bodies as Level 1 test pieces, and the outer surface of the porous bodies was observed visually and under a microscope for the presence or absence of damage. A 5-point rating was used, with 5 being no damage at all, 4 being damage with a diameter of 10 μm or less found within one body, 3 being damage with a diameter of 10 μm or less found within two to three bodies, 2 being damage with a diameter of 10 μm or less found within four to seven bodies, and 1 being damage that has progressed to two or more bodies, with a rating of 3 or above being considered a pass.

[0044] <Thin film> (With or without thin film and film thickness) A cross section parallel to the normal to the surface of the porous body was prepared, and the cross section was observed using an electron microscope to determine whether or not a thin film was present by observing the state in which the porous body and other parts formed a layered structure. The thickness of the non-porous part was measured at 10 randomly selected locations, and the arithmetic mean of the data from 8 locations excluding the maximum and minimum was determined as the thickness of the thin film.

[0045] (proportion of carbon atoms in thin film) The thin film portion was measured in the same manner as the (ratio of carbon atoms) in the <particles>.

[0046] [Example 1] A solution was formed by dispersing 15 parts by mass of multi-walled carbon nanotubes (as-produced cathode deposit, >7.5% MWCNT basis, OD×L7-15 nm×0.5-10 μm) (hereinafter, MWCNT) manufactured by Sigma-Aldrich, 10 parts by mass of aromatic polyimide, and 100 parts by mass of N-methylpyrrolidone (NMP).

[0047] The obtained solution was discharged from the outside of a nozzle having a double tube and allowed to travel 2 cm in the air, after which it was coagulated in a coagulation bath composed of pure water and then air-dried to obtain a porous body having a hollow cross-section and a fibrous form, i.e., a porous fiber.

[0048] The obtained porous fiber was baked in a nitrogen atmosphere at 610°C for 10 minutes to obtain a carbonized porous fiber. After that, a thin film was formed on the surface of the carbonized porous fiber by dip coating with an NMP solution of aromatic polyimide at a pull-up speed of 1 cm / min to obtain a composite porous body.

[0049] The composite porous body obtained was again fired in a nitrogen atmosphere at 610°C for 10 minutes to obtain a carbonized composite porous body, which was a fluid separation membrane. A plurality of the obtained fluid separation membranes were bundled and stored in a cylindrical container, both ends of the fluid separation membrane were fixed with an adhesive, and after the adhesive had solidified, the fluid separation membrane was cut with a cutter so that the hollow portion of the fluid separation membrane was exposed at the end of the cylindrical container, to obtain a fluid separation membrane module.

[0050] A mixed fluid of CO2 and nitrogen in a volume ratio of 50:50 was introduced into the obtained fluid separation membrane module, and the CO2 concentration was measured on both the non-permeate and permeate sides of the fluid separation membrane.It was confirmed that the CO2 concentration decreased on the non-permeate side and increased on the permeate side.

[0051] The results are shown in Table 1.

[0052] [Example 2] Except for using 2.1 parts by mass of MWCNT and 43 parts by mass of aromatic polyimide, a porous body, a composite porous body, and a fluid separation membrane module were obtained in the same manner as in Example 1. The results are shown in Table 1.

[0053] [Example 3] A solution was prepared by dispersing 15 parts by mass of multi-walled carbon nanotubes (as-produced cathode deposit, >7.5% MWCNT basis, OD×L 7-15 nm×0.5-10 μm) (hereinafter, MWCNT) manufactured by Sigma-Aldrich in 100 parts by mass of N-methylpyrrolidone (NMP).

[0054] A nylon fishing line with a diameter of 0.2 mm was immersed in the solution for 1 minute, then pulled up vertically at a speed of 1 cm / min to coat the material, and then air-dried. A porous body, a composite porous body, and a fluid separation membrane module were obtained in the same manner as in Example 1, except that this was used as the porous fiber, which was the porous body. The results are shown in Table 1.

[0055] [Example 4] Except for adding polyethylene glycol having a mass average molecular weight of 4,000 instead of the aromatic polyimide, a porous body, a composite porous body, and a fluid separation membrane module were obtained in the same manner as in Example 1. The results are shown in Table 1.

[0056] [Example 5] Except for using 1 part by mass of aromatic polyimide, a porous body, a composite porous body, and a fluid separation membrane module were obtained in the same manner as in Example 1. The results are shown in Table 1.

[0057] [Example 6] Except for using graphene oxide powder manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. instead of MWCNT, a porous body, a composite porous body, and a fluid separation membrane module were obtained in the same manner as in Example 1. The results are shown in Table 1.

[0058] [Example 7] Except for using 1 part by mass of aromatic polyimide, a porous body, a composite porous body, and a fluid separation membrane module were obtained in the same manner as in Example 6. The results are shown in Table 1.

[0059] [Example 8] Except for using SG-2000 manufactured by Nippon Talc instead of MWCNT, a porous body, a composite porous body, and a fluid separation membrane module were obtained in the same manner as in Example 1. The results are shown in Table 1.

[0060] [Example 9] Except for using 1 part by mass of aromatic polyimide, a porous body, a composite porous body, and a fluid separation membrane module were obtained in the same manner as in Example 8. The results are shown in Table 1.

[0061] [Table 1] [Industrial Applicability]

[0062] The porous body, composite porous body, fluid separation membrane module, fluid separation method, and gas separation device of the present invention have improved mechanical properties, are prevented from being damaged during transportation or use, and perform stable functions for a long period of time, and can be particularly suitably used in the field of gas separation.

Claims

1. A porous body composed of particles having an aspect ratio of 10 to 10,000.

2. 2. The porous body according to claim 1, comprising a component that connects at least a portion of particles having an aspect ratio of 10 to 10,000.

3. The porous body according to claim 1, characterized in that at least a part of the particles having an aspect ratio of 10 to 10,000 is selected from graphene, carbon nanotubes, cellulose nanofibers, talc, montmorillonite, and whiskers.

4. 3. The porous body according to claim 2, wherein a component connecting at least a portion of the particles having an aspect ratio of 10 to 10,000 contains 90 to 99.5 atomic % of carbon atoms.

5. 2. The porous body according to claim 1, which is in the form of a fiber or film having an aspect ratio of 10 to 30,000.

6. 6. The porous body according to claim 5, wherein the porous body is in the form of hollow fibers.

7. 7. The porous body according to claim 6, which is in the form of a hollow fiber having an outer diameter of 0.1 to 15 mm.

8. A composite porous body, comprising the porous body according to any one of claims 1 to 7, and a thin film having a thickness of 0.1 to 10 µm formed on the surface of the porous body.

9. 9. The composite porous body according to claim 8, wherein the components constituting the thin film contain 90 to 99.5 atomic % of carbon atoms.

10. A fluid separation membrane module comprising a plurality of the composite porous bodies according to claim 9 housed therein.

11. A method for separating fluids using the fluid separation membrane module according to claim 10, characterized in that a fluid containing two or more components is supplied to the fluid separation membrane module, and at least one stream for increasing the concentration of one component in the fluid and one stream for decreasing the concentration of one component in the fluid are provided.

12. A gas separation device comprising the fluid separation membrane module according to claim 10 as a component part.

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