JP2003012381A - Method of manufacturing inorganic porous body and inorganic porous body and gas separation module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inorganic porous body which is unnecessary to adjust the humidity, the surface of which is formed with a porous film of few pin hole, and the thickness of the film is uniform. SOLUTION: The inorganic porous film is characterized in that a sol containing a metal compound, water, and alcohol is made to coat over the surface of an inorganic porous support medium 2, thereafter the porous film 3 is formed by firing it, at this time it is especially preferable that the sol is to be prepared by adding a solution containing an acid to a solution containing a metal alkoxide and alcohol, and hydrolyzing while adjusting the amount of evaporation of the water and the alcohol, after that heating it.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for concentrating a specific gas, a device for concentrating a specific substance from a mixed solvent, a device for dehydrating from alcohol, a water treatment device for improving the purity of water, and a desalination device, Inorganic porous material suitably used for a device for separating a specific gas such as oxygen and carbon dioxide from a factory exhaust gas or a power plant, food-related, medical-related, a fuel cell for generating electricity using hydrogen gas and oxygen gas as a fuel, and a method for producing the same And the gas separation module.

[0002]

2. Description of the Related Art Conventionally, a separation membrane module capable of selectively permeating and separating a specific substance from a mixed solvent containing a plurality of substances is known.
An organic material such as a polymer resin or a metal film or an inorganic oxide film deposited on the surface of a porous body is used.

Such a thin film as a separation film is often produced by the sol-gel method because of the ease of the production method. Here, the sol-gel method is a sol in which fine particles of a metal oxide or a hydroxide are dissolved, starting from a solution of an organic or inorganic compound of a metal, hydrolysis of the compound in the solution, and a polymerization process. This is a method of heating the porous gel that has been made into a gel by advancing the reaction and producing an amorphous, glass, or polycrystalline body.

For example, it is described in JP-A-3-193679 that a titania suitable for use in an atmosphere containing water is prepared as a separation layer having an average pore diameter of 40 Å or less by a sol in an alcohol solvent. ing.

Further, it is possible to form a porous thin film by using a hydrosol solution containing titanium hydroxide or titanium oxide on one side of the porous support by utilizing hydrolysis with water instead of the organic solvent. It is proposed in Japanese Examined Patent Publication No. 5-61969.

[0006]

[Problems to be Solved by the Invention] JP-A-3-19367
In the case of TiO ₂ disclosed in JP-A-9, an alcohol solvent is used, so that the sol is quickly dried after being applied, and it is necessary to dry it in an atmosphere where the humidity is adjusted, which requires equipment and complicated steps. In addition, it is difficult to form a film because it easily penetrates into the pores of the support.

In Japanese Patent Publication No. 5-61969, a film is formed on a support using a water solvent. However, since the volatility of water is low, the drying time is too long, and the sol moves downward in the solvent during drying, and the sol accumulates in the lower part, causing the problem of non-uniformity of the film thickness and the drying. If insufficient, there was a problem that pinholes were generated during firing.

An object of the present invention is to provide an inorganic porous material having a porous film having a uniform film thickness and few pinholes on its surface, which does not require humidity adjustment, a method for producing the same, and a gas separation module. There is.

[0009]

The method for producing an inorganic porous material of the present invention is based on the finding that the viscosity and volatility of a solution can be easily adjusted by using a sol containing water and alcohol as a solvent. As a result, it is possible to reduce the number of pinholes and to fabricate an inorganic porous body of a porous film having a uniform film thickness of the porous film with simple equipment.

That is, a sol containing a metal compound, water and alcohol is prepared, and the sol is coated on the surface of the inorganic porous support and then fired to form a porous film. .

In particular, it is preferable to add an aqueous solution containing an acid to a solution containing a metal alkoxide and an alcohol for hydrolysis, and then heat while adjusting the evaporation amounts of water and alcohol to prepare a sol. The amounts of water and alcohol in the sol after hydrolysis can be easily adjusted, and a porous membrane having a uniform average pore diameter can be formed.

At this time, it is preferable to add an aqueous solution of the acid so that the amount of water is 1 to 100 mol with respect to 1 mol of the metal alkoxide to carry out hydrolysis. It is possible to control the pore size.

Further, it is preferable that the sol contains 0.001 to 1 mol of alcohol with respect to 1 mol of water. This optimizes volatility and viscosity, and by using this sol, it becomes possible to produce a porous film having a small pore size distribution with a more uniform film thickness.

Furthermore, the pH of the sol is 0.5 to 2.5.
Is preferred. This makes it possible to produce a sol having a uniform particle size and prevent gelation and precipitation.

Furthermore, it is preferable that the alcohol comprises at least one of methanol, ethanol, propanol and butanol. This makes drying after sol coating easier due to its high volatility, and since these alcohols are easily available and easy to handle,
Suitable for work.

The metal alkoxide is Ti, S
It is preferable to contain at least one of i, Zr and Mg. By using Ti, a titania porous film can be formed, an inorganic porous material used in an atmosphere containing water and water vapor can be obtained, and a fluid having a relatively large molecular diameter can be separated. Further, a porous film containing Si, Zr, Mg, etc. has high corrosion resistance and can be suitably used for separating a fluid having a small molecular diameter.

Furthermore, it is preferable that the average pore diameter of the porous film after firing is 0.5 to 50 nm.

The inorganic porous material of the present invention comprises a porous film formed on the surface of an inorganic porous support, and the average film thickness of the porous film is 0.1 to 50 μm, based on the average film thickness a. The ratio (b−c) / a of the difference between the maximum film thickness b and the minimum film thickness c is 0 to 1
It is characterized by being. With this configuration,
It is possible to produce an inorganic porous membrane having a small variation in film thickness and few pinholes, and an inorganic porous body that can be suitably used as a separation membrane having excellent gas permeation characteristics and gas separation characteristics can be realized.

Further, the gas separation module of the present invention comprises: a gas supply port; and the inorganic porous material according to claim 9, which is arranged so as to come into contact with the gas introduced from the gas supply port.
It is characterized by comprising an outlet for a gas rich in a specific molecule that has passed through the inorganic porous body and an outlet for a gas that does not pass through the inorganic porous body. With this configuration, the supplied gas can be easily separated and concentrated into the permeable component and the non-permeable component through the membrane by utilizing the pressure difference.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION The method for producing an inorganic porous material of the present invention will be described using a porous film made of titania (hereinafter referred to as Ti porous film) as an example. Also,
According to the present invention, at least one porous film may be provided, but also in the case of forming two layers, the case of forming a small diameter film (Si-Zr-O compound) on the Ti porous film will be described. The Si-Zr-O compound may be directly formed on the inorganic porous support.

First, in order to prepare an inorganic porous support,
Average particle size 0.05 to 10 μm, especially 0.1 to 2
A predetermined ceramic powder of μm is prepared, a desired organic binder is added thereto, and the mixture is molded into a desired shape by a known molding means such as press molding, extrusion molding, injection molding, cast molding, tape molding, and then fired. Thus, an inorganic porous support is prepared. The support is preferably fired in an oxidizing atmosphere to prevent residual carbon from remaining.

The above-mentioned inorganic porous support is preferably composed mainly of alumina in view of ease of production.
For example, a support may be prepared by molding a mixed powder of alumina powder and a sintering aid powder and firing it.

Next, a Ti porous film is formed on the surface of this support. For the preparation of the Ti porous film, a titania sol containing a metal compound, water and alcohol (hereinafter referred to as Ti sol) is prepared, and the obtained Ti sol is coated on the surface of the inorganic porous support and then fired. is important. By using a sol containing a metal compound, water and alcohol,
The viscosity and volatility of the solution can be easily adjusted.

For example, a titanium alkoxide (hereinafter referred to as Ti alkoxide) is dissolved in a dehydrated alcohol solvent such as ethanol, water for hydrolysis and an acid such as nitric acid for deflocculation are added, and Ti of an alcohol solvent is added. Make a sol. Then, this solution can be stirred with heating to volatilize the alcohol to adjust the contents of the alcohol and water. At the time of heating and stirring, alcohol or water may be replenished to adjust the concentrations of alcohol and water.

The aqueous solution of the acid added to the alcohol solution of the alkoxide has 1 to 100 moles of water in the aqueous solution of the acid, particularly 1 to 5 moles, relative to 1 mole of the alkoxide in the alcohol solution.
It is preferably 0, more preferably 1 to 20. This makes it possible to produce a uniform sol particle size and a thin film having a sharp pore size distribution.

As described above, an aqueous solution of an acid is added to a stock solution containing an alkoxide and an alcohol for hydrolysis, and then heated while adjusting the contents of water and alcohol to produce a Ti sol. It is possible to easily prepare a Ti sol of a water solvent in which the slag remains. Depending on the particle size of the sol, the alcohol component may be volatilized once to make a water solvent, and then alcohol may be added.

In particular, the obtained Ti sol contains 0.001 to 1 mol of alcohol, particularly 0.01 to 1 mol of water per mol of water.
It is preferable to make it so as to be contained in a ratio of 0.8 mol, and further 0.1 to 0.6 mol. By setting the alcohol concentration relative to water as described above, volatility and viscosity can be optimized, and a porous membrane having a small pore size distribution can be produced with a more uniform membrane.

Further, it is preferable to adjust the amount of acid to be added so that the pH of the Ti sol is 0.5 to 2.5.
When the pH is in the above range, the generation of precipitates disappears,
Further, gelation does not proceed, and it becomes easy to store the sol for a long period of time.

The alcohol used as the solvent for the Ti alkoxide can be used as long as it has a higher volatility as compared with water, but it is particularly preferable to use at least one of methanol, ethanol, propanol and butanol. Since these alcohols have high volatility, drying after sol coating becomes easier, and since these alcohols are easily available and easy to handle, they are suitable for work.

Next, the surface of the inorganic porous support is coated with the produced Ti sol. As a coating method, a known method can be used, but a dipping method in which an inorganic porous support is immersed in Ti sol and pulled up is particularly preferable.
By using the dipping method, at least one surface of the inorganic porous support can be uniformly coated with Ti sol.

Then, this is fired to form a porous film on the surface of the inorganic porous support. Upon firing, the Ti porous film has an average pore size of 0.5 to 50 nm, particularly 0.5 to 50 nm.
It is preferable to bake to a thickness of 40 nm, more preferably 0.5 to 30 nm. The porous membrane having such an average pore diameter is characterized in that only a specific substance can be permeated, and substances having different molecular diameters can be separated at the molecular level.

By controlling the firing temperature and firing time in firing, it becomes easy to obtain the above-mentioned porous body. That is, the firing temperature is 300 to 900 ° C., especially 400.
By setting the temperature to ˜800 ° C., and further to 450 to 700 ° C., a thin film having a sharp pore size distribution can be obtained. Also, the same effect can be obtained by prolonging the firing time.

According to the present invention, a porous film having a smaller diameter can be formed on the surface of the Ti porous film of the above-mentioned inorganic porous material to enhance the separation efficiency for separating small molecules. For example, a precursor sol is prepared through hydrolysis and polycondensation reaction using a simple or complex solution of a metal alkoxide containing Si (TEOS or the like) or a metal alkoxide containing Zr such as zirconium normal propoxide or zirconium normal butoxide as a starting solution. A small-diameter membrane can be produced by a step of coating on the surface of the inorganic porous material of the present invention, drying and then firing at a temperature of 350 to 700 ° C. The coating method of the small-diameter film is preferably a method of impregnating the support on which the titania layer is formed in the solution and pulling it up, because the operation is as easy as the titania layer and the handling is easy.

In such a method for producing a porous film, it is possible to produce a porous film having a uniform film thickness and few pinholes, without the need to adjust humidity. And Si, Zr
And small-diameter film 4 containing at least one of Al and Al
Can have an average pore size of 0.1 to 3 nm, and T
i Suitable for separating gas with smaller molecular diameter than porous membrane.

The inorganic porous material of the present invention can be produced by the above-mentioned method, and at least one layer of the porous membrane is formed on the surface of the inorganic porous support, and it is used as a gas separation membrane or an ultra membrane. It can be suitably used as a filtration membrane.

According to the present invention, it is important that the average film thickness of the porous film is 0.1 to 50 μm, and especially, the average film thickness is 0.1.
The thickness is preferably 5 to 30 μm, more preferably 0.5 to 15 μm. In addition, a small-diameter membrane can be provided on the porous membrane to further improve the separation efficiency.

If the thickness of the porous membrane is less than 0.1 μm, there is a risk that the surface of the support will be exposed, and gas will permeate the support having large pores without being separated, and the selection efficiency will decrease. Further, when it exceeds 50 μm, the gas permeation rate becomes small, and the residual stress of the film becomes high, so that part of the porous film may be peeled off or cracks may be generated, so that the gas separating function should be sufficient. I can't show it.

The ratio (b-c) / a of the difference between the maximum film thickness b and the minimum film thickness c with respect to the average film thickness a of the porous film is 0 to
It is important that it is 1. If this ratio is d, 0 ≦
By setting d ≦ 1, variation in film thickness is small and defects such as cracks and pinholes are small, so reliability can be improved and product life can be extended.

It is preferable to reduce the variation in the film thickness and increase the separation efficiency to 0 ≦ d ≦ 0.8, more preferably 0 ≦ d ≦ 0.5. As one means therefor, a small-diameter membrane is formed on the porous membrane. It is effective to provide it.

Further, since the porous membrane separates fluids,
Since it is preferably excellent in corrosion resistance, it is preferably made of ceramics. In particular, alumina is preferable from the viewpoint of adhesion to the alumina of the support, and titania is preferable from the viewpoint of being resistant to the environment in which water and water vapor exist.

In the gas separation module of the present invention, as shown in FIG. 1, the inorganic porous material 1 is the inorganic porous support material 2.
The porous membrane 3 having a large number of pores is formed on at least one surface of the.

The porous film 3 has a film thickness of 0.1 to 50 μm,
It is characterized in that 0 ≦ d ≦ 1 and is preferably made of titania.

The inorganic porous support 2 may have any shape such as a tubular shape or a plate shape. From the viewpoint of improving the mechanical strength and the membrane area per volume, the tubular shape has an outer diameter of 1 to 15 mm and a wall thickness. The thickness is preferably 0.2 to 3 mm, and in the plate shape, the thickness is preferably 0.2 to 10 mm.

The average pore diameter is 1 μm in order to suppress the generation of pinholes when the sol is applied uniformly.
Hereafter, it is more preferable that the thickness is 0.5 μm or less.

To obtain an average pore size of 1 μm or less, the average particle size of the ceramic is 1 μm or less, and further 0.5 μm.
It is desirable to be m or less. Further, for the purpose of reducing the pressure loss, the average pore size may be increased to smooth the gas flow.

In this case, the average pore diameter is preferably 1 μm or more, and more preferably 5 μm or more. Therefore, the average particle size of the ceramic is preferably 1 μm or more, and more preferably 5 μm or more. The separation membrane and its module produced as described above are composed of an inorganic material separation membrane having a heat resistance of 500 ° C. or more, and have sufficient heat resistance even if they are used for a long time.

According to the present invention, it is desirable that the inorganic porous support 2 has a small resistance to gas permeation, and specifically, the porosity is preferably 20% or more, particularly 25% or more in volume ratio. However, since the support 2 has sufficient mechanical characteristics, the porosity is preferably 50% or less, particularly 45% or less.

Further, in view of gas or liquid separation performance and gas or liquid permeability, porosity is 20 to 50%, average pore diameter is 0.02 to 2 μm, and surface roughness (Ra) is 2 μm or less, particularly 1 μm or less. Is desirable.

The shape of the above-mentioned inorganic porous support 2 is not limited and can be used by forming it into a desired shape. For example, a tubular, flat plate, corrugated plate or the like may be a gas-inorganic porous body made of porous glass hollow fiber, does not reduce the permeability of the fluid, to form a porous membrane on the surface, The porous support 2 is not particularly limited as long as it indicates the membrane.

For the inorganic porous support 2, ceramics such as alumina, zirconia, silica, cordierite, silicon nitride, silicon carbide or a composite thereof can be used. Considering heat resistance and cost, Alumina is preferred.

According to the present invention, the specific substance can be separated by the porous membrane 3, but the average fine particles in the porous membrane 3 are formed on the surface of the porous membrane 3 opposite to the porous support 2. It is also possible to separate a specific gas, in particular, by means of the small-diameter membrane 4 having an average pore size smaller than the pore size.

The small-diameter film 4 is made of, for example, Si, Zr and Al.
Of at least one of these compounds as the main component,
Average pore size 0.1 to 3 nm, film thickness 0.01 to 10 μ
It is desirable that it is m.

The structure used for separation by the ultrafiltration method is prepared by forming a porous membrane 3 made of titania on at least one side of the inorganic porous body 1 on one side of the inorganic porous support 2. . The ends may be sealed with an inorganic adhesive such as glass, an epoxy resin, a silicon resin, or a rubber stopper before use. The supply side comes into contact with the separated mixed solution and is pressurized by a pressure pump or the like. When pressurized, only specific components move to the permeate side through the membrane and are concentrated.

In the structure used for gas separation, a porous membrane 3 is formed on at least one side of the inorganic porous body 1 on one side of the inorganic porous support 2, and a small-diameter membrane 4 is formed thereon if desired. To do. The formed porous film 3 has an average pore diameter of 0.5 to 50 nm and a film thickness of 0.1 to 50 μm, which enables separation of gas in the angstrom order.

The inorganic porous material 1 of the present invention thus constructed is characterized in that it is a thin film with few defects such as cracks and pinholes because the thickness variation of the porous film 3 is small. It can be suitably used for a separation membrane module having a separation membrane through which a predetermined molecule preferentially permeates other molecules. Then, for example, air can be separated from the introduction port to be taken out as oxygen-enriched air concentrated to an oxygen concentration of 24 to 90% by volume, and for example, CO ₂ which causes global warming can be removed. It is possible to separate efficiently from ₂ .

Further, the gas separation module of the present invention comprises a gas supply port, the above-mentioned inorganic porous body 1 arranged so as to come into contact with the gas introduced from the gas supply port, and the inorganic porous body 1. It is provided with an outlet for a gas that permeates and is rich in a specific molecule and an outlet for a gas that does not permeate the inorganic porous body.

For example, as shown in FIG. 2, the gas separation module 10 of the present invention comprises the inorganic porous material 11 of the present invention, and the separation of fluid through the porous membrane 13 formed on the surface thereof. Is done. That is, gas is introduced from the gas supply port 16 attached to the housing 15, and the introduced gas passes through the inside of the tubular inorganic porous body 11 fixed by the support member 17, and the porous film provided on the surface. Thirteen
The separated gas that has permeated the exhaust gas is taken out from the separated gas outlet 18, and the exhaust gas that has not passed through the porous membrane 13 is exhausted from the exhaust gas outlet 19.

The housing 15 is formed of a member such as heat-resistant glass, metal such as stainless steel, ceramics such as alumina or zirconia that does not allow gas or liquid to pass therethrough, and is hermetically sealed from the outside. It is desirable that the metal has high mechanical properties. Further, when pressurizing or depressurizing the inside of the housing 15, metal such as stainless steel having high mechanical strength is preferable, and it is desirable that the metal has a substantially tubular body.

The inorganic porous material as described above is formed into a tubular shape,
The surface area can be increased by bundling or stacking one or more honeycomb-shaped, monolith-shaped, or plate-shaped ones.

In the case of a honeycomb shape or a monolith shape, as a porous body having an average pore diameter of 1 μm or more and a porosity of 20% or more, the gas permeated from the gas flowing through the through holes is discharged to the side surface through the pores. Further, the permeated gas may be collected by sealing one end of some through holes. When bundling a plurality of these materials, it is important to seal them so that the permeated gas, the mixed gas, and the non-permeated gas do not mix, as in the case of the tubular shape.

The shape of the inorganic porous material is not limited to the tube shape, the honeycomb shape, and the monolith shape as described above. In the gas separation module 20 shown in FIG. 3, a plurality of flat plate-shaped or corrugated plate-shaped inorganic particles are used. The porous body 21, the porous membrane 23 formed on the surface of the porous body 21, and the small-diameter membrane 24 formed on the porous body 21 are fixed by the support member 27, and the fluid introduced from the supply port 26 forms the laminated inorganic porous body 21. The fluid that comes in contact with and is introduced into the separation gas outlet 28 while passing through the inorganic porous body 21 and the porous membrane 23 formed on the surface thereof, and the gas that has not passed through the inorganic porous body 21 is exhaust gas. It is discharged from the discharge port 29.

The gas separation module having the above structure is
Since the inorganic porous material of the present invention is used, it is characterized by high gas separation efficiency and high permeation rate.
It can be suitably used for gas separation such as ₂ gas and oxygen enrichment, separation of toxic substances in solution, and separation of bacteria.

[0063]

EXAMPLES First, the purity is 99.9%, the average particle size is 0.1 μm.
3% by weight of methylcellulose as an organic binder, 10% by weight of a wax emulsion as a lubricant, and distilled water were added to and mixed with the alumina powder of, and a tubular molded body was produced by extrusion molding, and then the temperature was increased to 1200 ° C. And calcination, outer diameter 2.0mm, inner diameter 1.1mm, length 10cm
Then, an inorganic porous support having an average particle diameter of 0.2 μm, a porosity of 39%, a tubular shape, and mainly composed of α-alumina was prepared.

[0064] Then, titanium tetraisopropoxide (Ti (O-iso-C 3 H 6) 4) were mixed in an ethanol solvent, a nitric acid aqueous solution adjusted at a concentration shown in Table 1 with ion-exchanged water as a catalyst Add and stir. Sample N
o. In No. 1, titanium tetraisopropoxide was mixed using water as a solvent instead of alcohol, and then the above nitric acid aqueous solution was added and stirred.

While heating the obtained mixed solution, ion exchange distilled water was added to evaporate ethanol, and the molar ratio of water to alcohol was adjusted as shown in Table 1 to prepare a Ti sol. Sample No. In No. 6, titaniisopropoxide was mixed in an ethanol solvent, nitric acid alone was added, and the mixture was stirred.

Then, one side of the above inorganic porous support is capped and dipped in the sol to form a sol on the outer surface of the inorganic porous support, and after drying 5
An inorganic porous material was produced by firing at 00 ° C. for 1 hour.

Sample No. In Nos. 13 to 18, a small-diameter membrane was formed on the porous membrane. That is, tetraethoxysilane (TEOS) and zirconium tetra-n-butoxide (ZTNB) are dissolved in ethanol, and then TEO
A nitric acid aqueous solution (ion-exchanged water) adjusted to have S: ZTNB: nitric acid of 1: 0.5: 0.07 was added as a catalyst to prepare a silica-zirconia sol. An inorganic porous support is dipped in this sol, dried and then heated to 500 ° C.
Pore size 0.5n by firing for 1 hour
A small-diameter film having a thickness of m and a thickness of 0.3 μm was produced.

Further, the sample No. In No. 25, heating and stirring were carried out until the water solvent was completely changed, and then ethanol was added to prepare a sol.

The amount of adsorption of the obtained inorganic porous material was measured in vacuum and in air with different humidity, and the average pore diameter was measured by the Kelvin capillary condensation formula.

Further, pure gas permeation characteristics of He and SF ₆ were measured in order to evaluate the pore diameter and confirm the presence or absence of pinholes. For the measurement, supply gas to the film side to adjust the pressure,
The flow rate of the permeating gas was measured by opening the porous side to the atmosphere. The differential pressure between the membrane side and the porous side was 100 kPa, and the supply gas flow rate was 500 cc / min.

The measured permeation flow rate is used as one guideline for evaluating the permeation characteristics of the membrane by calculating the number of moles permeated through the membrane per unit area, which is called permeation coefficient, unit time, and unit pressure. Whether or not there is a pinhole is H, which has a small molecular diameter.
When the ratio He / SF _{6 of} e and the transmission coefficient of SF _{6 having} a large molecular diameter is smaller than 2, it was judged that the gas was flowing out from the pinhole.

The film thickness was observed using a scanning electron microscope, and a photograph of 10000 times was taken.
The film thickness at the location was measured to calculate the maximum film thickness, the minimum film thickness, and the average film thickness, and the film thickness variation (d) was obtained from d = (bc) / a. The results are shown in Table 1.

[0073]

[Table 1]

Sample No. of the present invention. 2-5 and 7-25
Has a ratio He / SF ₆ of 2.71 or more and an average film thickness of 1.4
˜9.8 μm, and the variation (d) was 89% or less.

On the other hand, the sample No. using the water only as the solvent was outside the scope of the present invention. In No. 1, since the ratio He / SF ₆ was 1.77, which was less than 2, it was judged that there was a pinhole. Further, the variation (d) in the film thickness was as large as 187%.

Further, sample No. outside the range of the present invention using only alcohol as a solvent. In No. ₆ , since the ratio He / SF ₆ was 1.03, which was less than 2, it was judged that there was a pinhole. Further, the variation (d) was as large as 113%.

[0077]

According to the gas separation module of the present invention,
The titania inorganic porous body produced using a sol composed of a mixed solvent of ethanol and water can be produced as an inorganic porous body having a uniform film thickness and no pinhole.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing an inorganic porous material of the present invention.

FIG. 2 is a schematic cross-sectional view showing a gas separation module of the present invention.

FIG. 3 is a schematic sectional view showing another gas separation module of the present invention.

[Explanation of symbols]

1, 11, 21 ... Inorganic porous material 2 ... Inorganic porous support 3, 13, 23 ... Porous membrane 4, 24 ... Small diameter membrane 10, 20 ... Gas separation membrane module 15 ... Housing 16, 26 ... Gas supply port 17, 27 ... Support member 18, 28 ... Separation gas outlet 19, 29 ... Exhaust gas outlet

Claims (10)

[Claims] 1. A sol containing a metal compound, water and alcohol is prepared, and after coating the surface of the inorganic porous support with the sol,
A method for producing an inorganic porous body, which comprises firing to form a porous film. 2. A sol is prepared by adding an aqueous solution containing an acid to a solution containing a metal alkoxide and an alcohol for hydrolysis and then heating while adjusting the evaporation amounts of water and alcohol to prepare a sol. The method for producing an inorganic porous body according to claim 1. 3. The method for producing an inorganic porous material according to claim 2, wherein the aqueous solution of the acid is added and hydrolyzed so that the amount of water is 1 to 100 moles with respect to 1 mole of the metal alkoxide. . 4. The method for producing an inorganic porous material according to any one of claims 1 to 3, wherein the sol contains 0.001 to 1 mol of alcohol with respect to 1 mol of water. 5. The method for producing an inorganic porous body according to claim 1, wherein the sol has a pH of 0.5 to 2.5. 6. The method for producing an inorganic porous material according to claim 1, wherein the alcohol comprises at least one of methanol, ethanol, propanol and butanol. 7. The metal alkoxide is Ti, Si, Zr.
7. The method for producing an inorganic porous body according to any one of claims 1 to 6, further comprising at least one of Mg and Mg. 8. The average pore diameter of the porous membrane after firing is 0.5 to
It is 50 nm, The manufacturing method of the inorganic porous body in any one of Claim 1 thru | or 7 characterized by the above-mentioned. 9. A porous film is formed on the surface of an inorganic porous support, and the average film thickness of the porous film is 0.1 to 50 μm.
And the ratio (b−c) / a of the difference between the maximum film thickness b and the minimum film thickness c with respect to the average film thickness a is 0 to 1. 10. An inorganic porous body according to claim 9, which is arranged so as to come into contact with a gas supply port and a gas introduced from the gas supply port, and a specific molecule which has permeated the inorganic porous body. A gas separation module comprising a gas outlet and a gas outlet that does not permeate the inorganic porous material.