JP2003047831A - Fluid separation filter and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluid separation filter less susceptible to moisture less liable to a change in percolation property and excellent in reliability. SOLUTION: A method for manufacturing a fluid separation filter has (a) a step of hydrolyzing a metal alkoxide to prepare a precursor sol, (b) a step of applying and drying the precursor sol on at least one surface of a porous support and carrying out firing to form an oxide film having a plurality of pores formed by cyclic siloxane bonds and silanol groups on the at least one surface of the porous support and (c) a step of exposing the oxide film to steam at 150-500 deg.C. Water can be uniformly adsorbed on the inner walls of numerous pores in the oxide film in advance and the objective fluid separation filter excellent in water resistance and reliability with the lapse of time can be obtained.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a plant for concentrating a specific gas, a plant for concentrating a specific substance from a mixed solvent, a plant for dehydrating alcohol, a water treatment plant or a desalination plant for increasing the purity of water. The present invention relates to a device for separating a specific gas such as oxygen and carbon dioxide from a factory exhaust gas or a power plant, a fluid separation filter that can be suitably used for food-related products, medical-related products, fuel cells, and the like, and a manufacturing method thereof.

[0002]

2. Description of the Related Art Conventionally, a porous body has been used as a catalyst carrier, an electrolytic partition wall, etc., including a filter for filtering and separating a specific gas from a mixed gas containing various gases, but it is safe and simple. The applicable range has been expanded, and the technology for separating and concentrating a specific gas using a porous body has been attracting attention in fields such as various combustion engines, the food industry, medical equipment, and waste treatment. However, since a polymer is generally used as the material of the film, there is a problem in heat resistance and corrosion resistance.

Therefore, a gas oxide film composed of a reaction product of at least one component selected from a hydrolyzate or a partial hydrolyzate of a metal alkoxide and an organosiloxane containing a terminal silanol group is prepared, and an inorganic material is used as a main material. It is possible to improve heat resistance by using
No. 23 publication.

However, as in the method described in Japanese Patent Application Laid-Open No. 2-149323, when an inorganic material is used, the heat resistance is improved, but the separation filter is easily affected by the outside air, so that the separation filter is exposed to the gas to be treated or the atmosphere. Water penetrates into the pores of the separation filter, and due to the presence of silanol (silanol) groups, water is adsorbed to the gas oxide film, which causes the pores to be clogged and the specific gas permeability to be repeatedly measured. There is a problem that the transmission characteristics are gradually deteriorated and a stable and large transmission amount cannot be obtained.

Therefore, in the glass oxide film, the silanol groups present on the surface and inside of the film are chemically converted by the silylating agent to form a siloxane bond, and the concentration of the silylating agent remaining in the film is adjusted. JP-A-8-24 discloses that a silanol group, which is an adsorption point of water existing in a membrane, is reduced to suppress adsorption of water and suppress deterioration of separation characteristics.
It is proposed in Japanese Patent Publication No. 600.

[0006]

However, in the method disclosed in JP-A-8-24600, the material is improved by forming a siloxane bond from the silanol group of the glass oxide film by a silylating agent. It is difficult to make the silanol group of the above into a siloxane bond, and there is a problem that the silanol group which becomes an adsorption point of water remains.

Further, even if a siloxane bond was once formed by the above treatment, it was converted back to a silanol group due to the presence of water, and there was a problem that the permeation characteristics changed with time.

[0008] Therefore, an object of the present invention is to provide a fluid separation filter which is less affected by moisture, has less change in permeation characteristics, and is excellent in reliability, and a manufacturing method thereof.

[0009]

According to the present invention, an oxide film made of an inorganic material having a large number of pores is exposed to water vapor at a specific temperature to adsorb water uniformly in the inner walls of the pores. It is based on the finding that a fluid separation filter that can be obtained with excellent water resistance and reliability over time can be obtained.

That is, (a) a step of hydrolyzing a metal alkoxide to prepare a precursor sol, and (b) applying the precursor sol to at least one of the surfaces of the porous support, drying and then firing. And forming an oxide film having a plurality of pores formed by a cyclic siloxane bond and silanol groups on at least one surface of the porous support, and (c) the oxide film at 150 ° C. And a step of exposing to water vapor at 500 ° C. As a result, a fluid separation filter having excellent water resistance and reliability over time can be obtained.

In particular, the partial pressure of the water vapor is 0.1 kPa to
It is preferably 100 kPa. As a result, water can be efficiently adsorbed in the pores in a short time.

Further, it is preferable that oxygen is contained in the atmosphere excluding water vapor in the step (c) in an amount of 5% by volume or more.
This makes it possible to suppress a sudden structural change on the membrane surface and prevent a significant decrease in the permeation rate of the membrane.

Further, it is preferable that the water vapor is continuously supplied to the oxide film. As a result, the local adsorption of water can be prevented and the water vapor can be uniformly supplied to the entire film, so that the water can be evenly adsorbed to the entire film.

Furthermore, it is preferable that the water vapor permeates the inside of the oxide film. This allows water to be adsorbed in the holes having smaller pores.

It is preferable that the temperature of the water vapor is higher than the operating temperature of the fluid separation filter. As a result, water that remains adsorbed and does not separate even at the operating temperature remains in the pores,
Stable transmission characteristics with little change over time can be obtained.

The average pore size of the oxide film is 0.4-1.
It is preferably 3 nm. As a result, even after water is adsorbed, a pore size suitable for separation can be obtained, and good separation can be performed.

It is preferable that the metal component of the metal alkoxide contains at least Si. This makes it possible to efficiently and stably form a plurality of pores composed of a siloxane bond and a silanol group.

Further, Ti, Z is added to the metal alkoxide.
It is preferable that at least one of r, Al and P is contained. These metals are present inside the siloxane bond and silanol groups and have a function of preventing deformation due to temperature rise, so that thermal stability is improved, and further chemical resistance and heat resistance can be improved.

The fluid separation filter of the present invention is a fluid separation filter comprising a porous support and an oxide membrane having a plurality of pores provided on at least one surface of the porous support. It is characterized in that the oxide film contains a siloxane bond and a silanol group, and the rate of change of nitrogen transmittance in repeated measurement is within 20%. As a result, the device is once stopped for maintenance of the device and the membrane is exposed to the atmosphere, and it is possible to have substantially the same transmission characteristics before the device was stopped even after the operation was started again.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION The fluid separation filter of the present invention is manufactured by using the sol-gel method. First, a metal alkoxide is prepared as a raw material. As the metal alkoxide, it is preferable to use silicon alkoxide because it forms a siloxane bond that forms pores and a silanol group.

The silicon alkoxide is preferably composed of tetraalkoxysilane represented by Chemical formula 1 and / or alkoxysilane represented by Chemical formula 2. These alkoxysilanes are relatively stable as long as they do not come into contact with water, and therefore have the characteristic that sol can be easily synthesized.
There is an advantage that a film having pores can be formed by baking at a relatively low temperature.

[0022]

[Chemical 1]

[0023]

[Chemical 2]

R _{1 to} R _{11 in} Chemical Formulas 1 and 2 represent any alkoxyl group or hydrocarbon group. For example, in Chemical Formula ₁ , R ₁ , R ₃ and R ₄ are OCH ₃ groups, R 1 Tetramethoxysilane in which ₂ is a CH ₃ group, R ₁ , R ₃ and R ₄ are OC ₂
Tetraethoxysilane in which H ₅ group and R ₂ are C ₂ H ₅ groups,
Tetrapropoxysilane in which R ₁ , R ₃ and R ₄ are OC ₃ H ₇ groups and R ₂ is a C ₃ H ₇ group and the like can be suitably used. In particular, it is desirable to use tetramethoxysilane or tetraethoxysilane in terms of raw material cost and film forming property.

The chemical formula 2 is, for example, R_Five~ R₉Is OCH
₃Group, R_TenIs CH₃Group and R₁₁Is C₂H_FourThe base 1, 2 bi
Striethoxysilylethane can be used, or
R_FiveIs CH₃Group, R₆Is CH₃CH₂Group, R₇Is CH₃C
H₂CH₂Group, R₈~ R_TenIs CH ₃CH₂Group, R₁₁Is CH₂C
H₂It is also possible to use compounds which are radicals.

The functional group, which is a part of the sol, causes a steric hindrance during the formation of the sol and can form a pore skeleton of a desired size in the sol. However, from the viewpoint of the stability of the sol, the functional group is It is desirable that it does not contain nitrogen (N).

Further, it is preferable that at least one alkoxide of Ti, Zr, Al and P is contained in the above silicon alkoxide. When these metals are contained as alkoxides, there are advantages that the thermal stability is improved, the chemical resistance of the film quality and the water resistance are improved.

Titanium alkoxide, zirconium alkoxide, aluminum alkoxide and phosphorus alkoxide are used as these metal alkoxides.

For example, the titanium alkoxide is preferably tetraethoxytitanium, tetrapropoxytitanium, tetrabutoxytitanium or the like, and particularly tetraethoxytitanium and tetrapropoxytitanium from the viewpoint of solubility in alcohol and film forming property of gel. Is desirable.

The zirconium alkoxide is preferably tetraethoxyzirconium, tetrapropoxyzirconium, tetrabutoxyzirconium or the like, and particularly tetraethoxyzirconium and tetrapropoxyzirconium in view of solubility in alcohol and gel film-forming property. Is desirable.

Further, the aluminum alkoxide is preferably tetraethoxyaluminum, tetrapropoxyaluminum, tetrabutoxyaluminum or the like, and particularly tetraethoxyaluminum or tetrapropoxyaluminum from the viewpoint of solubility in alcohol and gel film-forming property. Is desirable.

Further, the alkoxide of phosphorus is preferably trimethyl phosphate, triethyl phosphate, trimethyl phosphite, triethyl phosphite, etc., particularly in view of solubility in alcohol and gel film-forming property. Therefore, triethyl phosphite and trimethyl phosphite are preferable.

The amount of these metal alkoxides added is 0.05 to 1 mol of the silicon alkoxide from the viewpoint of improving heat resistance and water resistance and stability of the sol produced during production.
It is desirable that the amount is 1.0 mol, particularly 0.1 to 1.0 mol. If the amount of metal added is less than 0.05 mol, the effect of increasing heat resistance and water resistance tends to be low,
On the other hand, if the amount exceeds 1.0 mol, the stability of the sol produced during production is poor, and precipitation or the like tends to make it difficult to form an oxide film.

Next, each of the above alkoxides is dissolved in a solvent. As the solvent, alcohols such as methanol, ethanol, propanol, butanol, 2-methoxyethanol, and 2-ethoxyethanol are preferably used, but the solubility of the alkoxide and the affinity for the gel support and the drying property are preferable. A lower alcohol such as methanol or ethanol is optimal in terms of film-forming property.

With respect to tetraalkoxysilane, 1 to 100 mol, preferably 1 to 20 mol, of water is added together with a solvent together with a solvent together with an acid and hydrolyzed to give a precursor sol. It is desirable to make it so that the hydrolyzed portion of the tetraalkoxysilane reacts with the other alkoxysilane and zirconium alkoxide to enhance the homogeneity of the composition in the solution.

That is, when the amount of water is less than 1 mol, hydrolysis is insufficient and siloxane bond does not proceed, so that film forming property is poor and cracks may occur in the film or peeling of the film may occur. This is because, if the amount of water is more than 100 mol, hydrolysis may proceed too rapidly, precipitation may occur, and a stable sol may not be obtained.

On the other hand, for producing a porous support (hereinafter abbreviated as support), for example, a purity of 99.8% by weight or more,
A predetermined amount of binder, lubricant, plasticizer, water and the like are added to and mixed with alumina raw material powder having an average particle diameter of 0.1 to 2.0 μm, and the resulting mixture is press-molded, extrusion-molded, injection-molded, It is formed by a known forming means such as cold isostatic pressing. After that, the molded body is placed in the atmosphere at 1000 to 1500.
A support can be obtained by baking at ° C.

The support has a porosity of 20% or more,
It is desirable to have a flat surface having an average pore diameter of 0.05 μm or more and a surface roughness (Ra) of 0.1 to 2 μm, an inner diameter of 0.5 to 5 mm, and a wall thickness of 0.2 to 5
A tubular body of mm is desirable.

In order to improve the film forming property of the oxide film on the surface of the support, it is desirable to form an intermediate layer. As a result of the improvement of the film forming property, the thickness of the oxide film can be reduced. The processing speed of gas separation is improved. This intermediate layer has a large number of pores inside and has a structure that allows gas to pass therethrough. Then, a sol-gel method or the like is used so that the average pore diameter of the intermediate layer is smaller than the average pore diameter of the support and larger than the average pore diameter of the oxide film. Specifically, it is preferably 1 to 100 nm, and particularly preferably 1 to 50 nm.

As the intermediate layer, for example, when the support is an α-alumina sintered body, α-alumina and γ-alumina are suitable, and the method for forming the intermediate layer is, for example,
A boehmite sol is prepared by hydrolyzing an aluminum alkoxide such as aluminum secondary butoxide, and the boehmite sol is adhered and formed on the surface of the porous support.

As a method for depositing the boehmite sol on the surface of the support, a method of applying or injecting boehmite sol, or a method of impregnating and pulling up the porous support in a boehmite sol solution is preferably used.

After that, the deposited boehmite sol is dried and gelled, and the boehmite sol is heat-treated at 400 to 1000 ° C., particularly 400 to 800 ° C. in the atmosphere to form an intermediate layer on the surface of the support. it can. If the baking temperature is lower than 400 ° C., the bonding strength of the intermediate layer to the support is weak and the intermediate layer peels off.
This is because if the temperature is higher than 0 ° C., the sintering proceeds excessively and the pore size of the intermediate layer becomes large, so that the desired pore size cannot be obtained.

Next, the precursor sol is deposited and formed on the surface of the support or the intermediate layer by a method similar to the method for forming the intermediate layer, which is dried and gelled, and then in air at 350.
By heat-treating at ˜700 ° C., especially 400-600 ° C., the siloxane bond of Si—O proceeds in the gel to form a strong film, and the organic functional groups are decomposed and removed by the heat treatment to form pores. .

If the baking temperature is lower than 350 ° C., the siloxane bond cannot be made strong, a stable film cannot be formed, and the decomposition and removal of the organic functional group are incomplete. It is not possible to obtain pores with a diameter of. Further, when the firing temperature is higher than 700 ° C., the oxide film is crystallized and the pores in the film disappear.

Since the pores of the oxide film change depending on the temperature and time during firing, the average pore diameter is 0.4.
~ 1.3 nm, especially 0.4-1.0 nm, and even 0.4
It is preferable to control the firing conditions so that the thickness becomes 0.8 nm.

According to the present invention, the oxide film obtained as described above is exposed to water vapor at 150 to 500 ° C., particularly at a temperature above the operating temperature at which the oxide film is used. The major feature is that water is adsorbed in the pores.

Specific examples of the method include a method of treating water with a gas containing oxygen using bubbling with steam adjusted to a desired concentration, a method of hydrothermal treatment in an autoclave, and the like. At this time, the partial pressure of water vapor is adjusted by changing the temperature of water during bubbling.

Here, the partial pressure of water vapor is 0.1 to 100.
kPa, particularly 0.2 to 90 kPa, further 0.3 to 80
It is preferably kPa. With this pressure, there is an advantage that water can be adsorbed uniformly on the entire surface of the film with a structural change in the film quality. Further, it is preferable to set the volume concentration of water vapor in the range of 5 to 85%, particularly 10 to 50%, from the viewpoint of stability of the film and workability.

Further, the coexistence of oxygen with water vapor has the advantage that abrupt structural changes on the membrane surface can be suppressed and deterioration of the transmission characteristics can be suppressed. Oxygen is contained in an atmosphere excluding water vapor of 5% by volume or more, particularly oxygen. The content is preferably 8% by volume or more, more preferably 10% by volume or more.

Further, by continuously supplying water vapor, water can be evenly supplied to the entire surface of the film, and water is efficiently adsorbed in the pores. In particular, the effect of adsorbing water into the pores becomes more remarkable by forcibly permeating the water vapor into the pores.

In this way, it is possible to manufacture a fluid separation filter which is less affected by moisture, has less change in permeation characteristics, and is excellent in reliability.

Next, the fluid separation filter manufactured by the above manufacturing method will be described. As shown in Figure 1,
The gas separation filter 1 is composed of a porous support 2 and an oxide film 3 formed on at least one surface of the support 2. A large number of pores 4 are formed in the oxide film 3, and an intermediate layer 5 is optionally provided between the support 2 and the oxide film 3.

The bonding state of the oxide film 3 is, as shown in FIG. 2, an amorphous state having a plurality of pores 14 formed by cyclic siloxane bonds having a skeleton structure formed by connecting -Si-O-. According to the present invention, a silanol group is bonded to at least a part of the inner wall surface of the pores 14, and the steam treatment results in the formation of water on the inner wall surface of the pores as shown in FIG. It is important to be in the adsorbed state. As described above, when water is adsorbed on the silanol group, there is an advantage that the water once adsorbed is unlikely to be separated even when the surrounding environment changes.

In addition, in the oxide film 3, the average pore diameter of the pores 4 formed in the oxide film 3 is 0.4 to 1.3 nm, in particular, 0. 4-1.0
nm, and more preferably 0.4 to 0.8 nm.

Furthermore, in order to improve the heat resistance and water resistance of the oxide film 3, part of Si in the oxide film 3 is Ti, Z.
It is desirable to have a structure in which at least one metal selected from r, Al, and P is substituted. Since the metal content improves water resistance, heat resistance, and reliability, SiO ₂ is a metal oxide with respect to 1 mol. Converted to 0.05 to 1.0 mol, especially 0.1 to
A ratio of 1.0 mol is desirable.

Further, the oxide film 3 deposited on the surface of the porous support 2 does not generate a reaction product at the interface with the support 2 and is layered on the surface of the porous support 2. It is desirable to be coated to form a smooth surface, and the thickness of the oxide film 3 is 0.01 to 5 μm, particularly 0.01 to 3 μm, and further 0.01 to 2 μm from the viewpoint of improving the separation performance. Is desirable.

On the other hand, the support 2 is 0.05 to 5 μm, and particularly 0.05 to 5 μm, in that it is permeable to gas, has the strength required for the structure, and enhances the film forming property of the oxide film 3. It is desirable to have a pore size of ˜3 μm, more preferably 0.05 to 1 μm. Further, in order to improve the film forming property of the oxide film 3, the support 2 preferably has a smooth surface.

In order for the mixed gas to permeate through the support 2 without applying a high pressure, the support 2 preferably has a porosity of 20% or more, and the strength of the support 2 is secured. When the filter 1 is assembled, the support 2
In order to prevent the particles from being damaged or the particles constituting the support 2 from being shed during the operation, the porosity of the support 2 is 20%.
It is desirable that it is -50%, especially 30-45%.

The support 2 can be formed of ceramics containing α-alumina or stabilized zirconia as a main component, silica-based glass (phase-separating glass), or the like, but it has high heat resistance, can be easily manufactured, and is inexpensive. From the point of view, it is desirable that the ceramic is mainly composed of α-alumina.

In order to improve the film forming property of the oxide film 3,
The support 2 preferably has a smooth surface having a surface roughness Ra of 0.1 to 2.0 μm.

The shape of the support 2 used as the fluid separation filter is not particularly limited, and may be a flat plate or a tubular body. However, in view of gas separation efficiency and handling of the filter, the tubular body is a tubular body. Is desirable.

When the shape of the support 2 is a tubular body, the outer diameter of the tubular body is 0.5 to 0.5 in order to increase the area ratio of the oxide film 3 per unit volume and to enhance the gas separation efficiency.
About 5 mm, especially 0.5 to 4 mm, and further 0.5 to 3 m
The thickness of the tubular body is preferably 0.2 to 5 mm, particularly 0.2 to 3 mm, and more preferably 0.2 to 2 mm in order to maintain strength that does not hinder handling. . Further, in the case of a flat plate shape, the thickness of the support 2 is 0.3 mm or more, particularly 0.3 to 10 in terms of strength.
mm, and more preferably 0.3 to 5 mm.

According to the present invention, the oxide film 3 is deposited on the inner surface and / or the outer surface of the support 2.
Has a thickness of 0.01 to 5 from the viewpoint of improving the processing speed of gas separation and producing an oxide film without defects such as pinholes.
μm, particularly 0.01 to 3 μm, further 0.01 to 2 μm
Is desirable.

The gas separation filter 1 of the present invention having the above structure can maintain high gas separation performance over a wide temperature range from room temperature to 500 ° C. from the viewpoint of heat resistance and durability of the oxide film 3.

[0065]

[Example] α- with a purity of 99.9% and an average particle size of 0.1 μm
After adding an organic binder, a lubricant, a plasticizer, and water to the alumina powder and mixing them, and extruding to form a tubular body,
Calcinated in air at 1200 ° C, mainly consisting of α-alumina, inner diameter 2.3 mm, wall thickness 0.4 mm, length 250 m
A support body having an average pore diameter of 0.2 μm and a porosity of 39% was prepared in a tubular body of m. Further, the outer surface of this outer surface is R
Polishing was performed so that a was 0.3 μm or less.

[0066]

[Chemical 3]

Further, 1 mol of aluminum secondary butoxide (Chemical Formula 3) was added to 110 mol of water for hydrolysis, nitric acid was further added, and the mixture was refluxed for 16 hours to prepare a boehmite sol. Then, the tip of the above support is capped and impregnated into the boehmite sol solution,
Hold for 0 seconds, remove at a speed of 5 mm / sec, and leave at room temperature for 2
After drying for a period of time to gelate the boehmite sol, the step of firing the support coated with the gel in the atmosphere at 500 ° C. is repeated 4 times to form γ on the outer surface of the α-alumina porous support. An intermediate layer of alumina was deposited.
Next, 1 mol of water is added to 1 mol of the silicon alkoxide represented by Chemical formula 1, and a solvent containing HCl is added and mixed to prepare a partially hydrolyzed sol. The alkoxysilane and the solvent to be added are added so that the total amount of silicon alkoxide (Chemical formula 1 + Chemical formula 2) is 1 mol, and the mixture is stirred under a nitrogen stream, and then Ti, Z, if desired.
A metal alkoxide containing at least one of r, Al, and P (referred to simply as metal alkoxide in Examples) was added together with a solvent to prepare a composite alkoxide. Then, a mixed solution of 9.3 mol of water and ethanol was added to the above composite alkoxide to hydrolyze and stirred to prepare a precursor sol. In Table 1, chemical formula 1, chemical formula 2, metal alkoxide,
The type of solvent, the ratio of chemical formula 2 / chemical formula 1, the ratio of metal alkoxide / silicon alkoxide (B / A) and the amount of water added are shown.

The support on which the intermediate layer had been formed was immersed in the solution of the obtained precursor sol for 30 seconds, pulled up at a speed of 5 mm / sec, and dried at room temperature for 1 hour, and subsequently, Table 1 Firing for 1 hour at the temperature
A series of operations of drying and firing was repeated four times to deposit and form an oxide film containing Si on the intermediate layer. The average pore diameter of the oxide film after the firing was determined by the argon adsorption method and is shown in Table 1.

Next, the supporting tube on which the obtained oxide film was deposited was exposed to water vapor under the conditions shown in Table 1 to adsorb water. In this steam treatment, a support tube is installed in a container, and steam is carried out together with a carrier gas at a flow rate of 100 ml / min.
Water vapor was brought into contact with the oxide film, the intermediate layer, and the inner wall surfaces of the pores of the support tube by flowing for a minute. At this time, if desired,
The oxide film was exposed to the water vapor by forcibly flowing the water vapor.

A gas separation module was prepared by using one of the obtained fluid separation filters, the inside of the module was heated to the test temperature shown in Table 1, and the inside of the tube was opened to the atmosphere.
With the pressure set to 00 kPa (atmospheric pressure), nitrogen 20
Flow the flow rate of 0 kPa (2 atm) at a rate of 200 ml / min, measure the permeation flow rate of the gas collected at the permeation gas outlet, and express it as the permeation amount of nitrogen gas / (membrane area × differential pressure × time). The transmittance of the generated nitrogen gas was calculated.

In the same manner, the transmittance of CF ₄ gas was obtained, and the transmittance coefficient ratio α (nitrogen transmittance / CF ₄ transmittance) was determined. The rate of change represents the change in transmittance before and after standing in the air, where A is the transmittance before standing in the air and B is the transmittance after standing in the air, which is (B−A) / A × 100 (%). expressed. Here, leaving in the atmosphere means leaving in a container having a relative humidity of 100% and a temperature of 25 ° C. for 24 hours. The results are shown in Table 1.

[0072]

[Table 1]

Sample No. of the present invention. Nos. 1 to 33 have a nitrogen transmittance of 2.1 × 10 ⁻⁸ mol / (m ² · sec · Pa) or more, a transmittance coefficient ratio α of 2 or more, and a transmittance change rate of 15%.
It was below. In addition, by infrared absorption analysis, each had a siloxane bond and a silanol group.

Further, the sample No. outside the scope of the present invention, which omits the step (c), Sample No. 34 has a small water vapor temperature of 120 ° C. 35 and the temperature of steam is as high as 600 ° C., which is outside the range of the present invention. In all Nos. 36, the rate of change in nitrogen transmittance was 23.8% or more.

[0075]

According to the present invention, an oxide film having a large number of pores is exposed to water vapor at 150 to 500 ° C., and water is preliminarily and uniformly adsorbed in the inner walls of the pores, whereby water resistance and A fluid separation filter having excellent temporal reliability can be realized.

Further, since the pore diameter can be easily controlled within a predetermined range, the selectivity of permeation of a specific gas is improved, and the inclusion of a metal in the oxide film further improves the corrosion resistance and heat resistance. A superior fluid separation filter can be manufactured.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view of a fluid separation filter of the present invention.

FIG. 2 is a schematic diagram showing a bonded state of pores in the oxide membrane of the fluid separation filter of the present invention.

FIG. 3 is a schematic diagram showing a bonded state when water is adsorbed on the pores of the oxide membrane of the fluid separation filter of the present invention.

[Explanation of symbols]

1 ... Gas separation filter 2 ... Porous support 3 ... Oxide film 4, 14 ... Pore 5: Middle layer

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) B01D 71/70 500 B01D 71/70 500 H01M 8/06 H01M 8/06 R

Claims (10)

[Claims] 1. A process of (a) hydrolyzing a metal alkoxide to prepare a precursor sol, and (b) applying the precursor sol to at least one surface of a porous support, drying the sol, and then baking the same. And forming an oxide film having a plurality of pores formed by a cyclic siloxane bond and silanol groups on at least one surface of the porous support,
(C) exposing the oxide film to water vapor at 150 to 500 ° C., the method for producing a fluid separation filter. 2. The partial pressure of the water vapor is 0.1 to 100 kPa.
The method for manufacturing a fluid separation filter according to claim 1, wherein 3. The atmosphere excluding water vapor in the step (c) contains oxygen in an amount of 5% by volume or more.
Alternatively, the method for manufacturing the fluid separation filter according to the second aspect. 4. The method for manufacturing a fluid separation filter according to claim 1, wherein the water vapor is continuously supplied to the oxide film. 5. The method for manufacturing a fluid separation filter according to claim 1, wherein the water vapor permeates the inside of the oxide film. 6. The method for producing a fluid separation filter according to claim 1, wherein the temperature of the water vapor is higher than the operating temperature of the fluid separation filter. 7. The average pore diameter of the oxide film is 0.4 to 1.
It is 3 nm, The manufacturing method of the fluid separation filter in any one of Claim 1 thru | or 6 characterized by the above-mentioned. 8. The method for producing a fluid separation filter according to claim 1, wherein the metal component of the metal alkoxide contains at least Si. 9. The metal alkoxide further contains Ti, Zr,
9. The method for manufacturing a fluid separation filter according to claim 8, wherein at least one of Al and P is contained. 10. A fluid separation filter comprising a porous support and an oxide membrane provided on at least one surface of the porous support and having a plurality of pores, wherein the oxide membrane is A fluid separation filter comprising a siloxane bond and a silanol group, wherein the rate of change of nitrogen permeability in repeated measurement is within 20%.