JP2015171691A - Ceramic filter manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ceramic filter manufacturing method capable of enhancing the film forming accuracy of a ceramic separation membrane.SOLUTION: A ceramic filter manufacturing method comprises: an elastic member arranging step of arranging an elastic member 4 having elasticity on the inner side of a substrate 2; a film precursor forming step of dipping the substrate 2 with the elastic member 4 arranged on the inner side thereof, in a raw material solution 5 containing a material for a ceramic separation membrane thereby to form a film precursor in a film forming region 211 in the outer circumference 21 of the substrate 2; and a film forming step of forming the ceramic separation membrane from the film precursor formed in the film forming region 211 of the outer circumference 21 of the substrate 2. In the elastic member arranging step, the elastic member 4 is arranged in an opposing region 221 of the inner circumference 22 of the substrate 2 opposing the film forming region 211 of the outer circumference 21 of the substrate 2.

Description

  The present invention relates to a method for producing a ceramic filter used for solid-liquid separation, solvent dehydration and the like.

  Conventionally, as a filter used for solid-liquid separation, solvent dehydration, and the like, for example, a ceramic filter in which a ceramic separation membrane is formed on the outer peripheral surface of a porous cylindrical base material is known. As the ceramic separation membrane, for example, a ceramic porous membrane made of zeolite membrane or alumina is used.

  As a method for producing a ceramic filter, for example, a porous cylindrical substrate with both ends sealed is immersed in a raw material solution, and a membrane precursor of a ceramic separation membrane (zeolite seed crystal, alumina, etc. A method of coating a ceramic separation membrane (zeolite membrane or ceramic porous membrane) from this membrane precursor is disclosed (for example, see Patent Document 1).

JP 2007-90233 A

  However, in the conventional method, a porous cylindrical base material sealed at both ends is immersed in the raw material solution. At this time, since the base material is porous, the raw material solution is outside of the base material (outer peripheral surface). From the side) to the inside, and a liquid pool may be formed inside the substrate. Therefore, when pulling up the base material from the raw material solution, a part of the film precursor coated on the outer peripheral surface of the base material is pushed up because the raw material solution that has entered inside the base material flows backward to the outside of the base material. It floats or minute bubbles remaining inside the substrate move to the film precursor. These were the causes of membrane defects such as floating (peeling), dripping and pinholes in the ceramic separation membrane.

  The present invention has been made in view of such a background, and an object of the present invention is to provide a method for manufacturing a ceramic filter capable of increasing the film formation accuracy of a ceramic separation membrane.

  The method for producing a ceramic filter of the present invention is a method for producing a ceramic filter in which a ceramic separation membrane is formed on the outer peripheral surface of a porous cylindrical substrate, and an elastic member having elasticity inside the substrate. The base material with the elastic member disposed inside is immersed in a raw material solution containing the raw material of the ceramic separation membrane, and a film precursor is formed in the film forming region on the outer peripheral surface of the base material. A film precursor forming step of forming a body, and a film forming step of forming the ceramic separation film from the film precursor formed in the film forming region of the outer peripheral surface of the base material, and the elastic In the member disposing step, the elastic member is disposed at least in a region facing the inner peripheral surface of the base material facing the film forming region on the outer peripheral surface of the base material.

  In the method for producing a ceramic filter, the elastic member is arranged inside the base material in the elastic member arranging step. At this time, the elastic member is placed in contact with at least the facing region of the inner peripheral surface of the base material facing the film forming region of the outer peripheral surface of the base material. Therefore, when the base material is immersed in the raw material solution, the elastic member can suppress the raw material solution from entering the inside of the base material. Therefore, when the soaked substrate is pulled up from the raw material solution, the raw material solution that has entered the inside of the base material starts from the opposing region (region facing the film forming region for forming the film precursor) on the inner peripheral surface of the base material. Backflow to the outside of the material can be suppressed by the elastic member.

  As a result, the film precursor formed on the outer peripheral surface of the base material is pushed up by the raw material solution that flows backward from the inside to the outside of the base material when the base material is pulled up, and the fine bubbles remaining inside the base material Can be prevented from moving to the film precursor. And the generation | occurrence | production of the film | membrane defects, such as a float (peeling), dripping, and a pinhole, of the ceramic separation film formed into a film based on a film | membrane precursor can be suppressed. As a result, the ceramic separation membrane can be accurately formed on the outer peripheral surface of the substrate.

  Thus, according to this invention, the manufacturing method of the ceramic filter which can raise the film-forming precision of a ceramic separation membrane can be provided. That is, a ceramic filter provided with a high-quality ceramic separation membrane free of membrane defects can be obtained.

  Here, in the method for producing a ceramic filter, in the elastic member arranging step, the elastic member may be arranged on the entire inner peripheral surface of the base material. In this case, it is possible to enhance the effect of suppressing the penetration of the raw material solution into the base material and the back flow of the raw material solution from the base material by the elastic member.

  Moreover, it is preferable that the outer diameter of the said elastic member before arrange | positioning inside the said base material is larger than the internal diameter of the said base material. In this case, in the elastic member arranging step, the elastic member is arranged in close contact with the inner peripheral surface (opposed region) of the base material. Thereby, the effect which suppresses the penetration | invasion of the raw material solution to the base material inside and the backflow from the base material inside of the raw material solution by an elastic member can be heightened. In addition, what is necessary is just to set the outer diameter of an elastic member to the magnitude | size which can be arrange | positioned inside a base material, without damaging a base material.

  In addition, after the film precursor forming step, a drying step of drying the film precursor is performed in a state where the elastic member is disposed inside the base material. After the drying step, from the inside of the base material It is preferable to remove the elastic member. That is, the film precursor before drying may have fluidity and the like. Therefore, by removing the elastic member after drying both the base material and the film precursor, the elastic member is removed before the film precursor is dried, that is, in a state where the film precursor has fluidity and the like. Compared to the case, there is no fear of damaging the film precursor when removing the elastic member. Thereby, a membrane precursor can be formed with high accuracy on the outer peripheral surface of the substrate, and the film formation accuracy of the ceramic separation membrane can be increased.

  In addition, as a material constituting the elastic member, for example, a polymer material excellent in elasticity and flexibility is suitable. Further, the characteristics required for the elastic member include not dissolving in the raw material solution and not swelling / water absorption so as not to hinder the effects of the present invention. If the elastic member elutes into the raw material solution, the components of the raw material solution may change, which is not preferable. In addition, when the elastic member swells and absorbs water, the amount of the raw material solution penetrating into the base material differs depending on the individual base material, and the film thickness variation of the ceramic separation membrane increases, which is not preferable.

  When the solvent of the raw material solution is water, examples of the polymer material constituting the elastic member include silicon rubber, silicon sponge, silicon tube, urethane rubber, and urethane sponge. A rubber balloon can also be used. In this case, an elastic member can be arrange | positioned inside a base material by arrange | positioning a rubber balloon inside a base material and inflating this.

  Moreover, as a material which comprises the said base material, ceramic materials, such as an alumina, a titania, a zirconia, a silica, a silicon nitride, a silicon carbide, an inorganic type binder, can be used, for example. Examples of the inorganic binder include glass frit, kaolin, talc (feldspar, quartzite) and the like.

  Further, the base material may be constituted only by a support made of the above-mentioned material, for example, an intermediate film (intermediate layer) for improving the adhesion of the ceramic separation membrane on the outer peripheral surface of the support. It may be formed and configured. Moreover, the pore diameter, porosity, etc. of the base material are not particularly limited, and can be appropriately set according to the application.

  Further, as the ceramic separation membrane, for example, a ceramic porous membrane formed by firing ceramic fine particles such as alumina, titania, zirconia, silica, silicon nitride, silicon carbide, a zeolite membrane, or the like can be used.

  Further, when a ceramic porous membrane is used as the ceramic separation membrane, its pore diameter, porosity, film thickness and the like are not particularly limited, and can be appropriately set according to applications and the like. The pore diameter and porosity can be controlled by the particle size of the raw material of the ceramic separation membrane contained in the raw material solution, and the film thickness can be controlled by the raw material concentration in the raw material solution, the number of film formations, etc. .

In Embodiment 1, (a) is a perspective view which shows a ceramic filter, (b) is sectional drawing which shows the axial direction cross section of a ceramic filter. In Embodiment 1, (a) is a perspective view which shows a base material, (b) is sectional drawing which shows the axial direction cross section of a base material. In Embodiment 1, it is sectional explanatory drawing which shows the state which has arrange | positioned the elastic member inside the base material. In Embodiment 1, it is explanatory drawing which shows the state which immersed the base material which has arrange | positioned the elastic member inside the raw material solution. In Embodiment 1, it is sectional explanatory drawing which shows the state which formed the film | membrane precursor in the film | membrane formation area of the outer peripheral surface of a base material. In Embodiment 2, it is sectional explanatory drawing which shows the state which has arrange | positioned the elastic member inside the base material. In other embodiment, (a) is a perspective view which shows a base material, (b) is a perspective view which shows a ceramic filter. In other embodiment, (a) is a perspective view which shows a base material, (b) is sectional drawing which shows the axial cross section of a base material. In other embodiment, (a) and (b) are sectional explanatory drawings which show the state which has arrange | positioned the elastic member inside the base material.

Embodiments of the present invention will be described with reference to the drawings.
(Embodiment 1)
First, the ceramic filter manufactured by the manufacturing method of the ceramic filter of this embodiment is demonstrated.

  As shown in FIGS. 1A and 1B, the ceramic filter 1 includes a porous cylindrical substrate 2 and a ceramic separation membrane 3 formed on the outer peripheral surface 21 of the substrate 2. The cylindrical substrate 2 is a support made of porous alumina. The base material 2 has an outer diameter of 14 mm, an inner diameter of 10 mm, and an overall length of 200 mm. The ceramic separation membrane 3 is a ceramic porous membrane made of alumina. The film thickness of the ceramic separation membrane 3 is 60 μm.

Next, the manufacturing method of the ceramic filter of this embodiment is demonstrated.
As shown in FIGS. 2 to 5, the ceramic filter manufacturing method of the present embodiment includes an elastic member arranging step of arranging an elastic member 4 having elasticity inside the base material 2, and a raw material for the ceramic separation membrane 3. A film precursor forming step of immersing the base material 2 in which the elastic member 4 is disposed inside the raw material solution 5 to form the film precursor 30 in the film forming region 211 on the outer peripheral surface 21 of the base material 2; A film forming step of forming the ceramic separation film 3 from the film precursor 30 formed in the film forming region 211 on the outer peripheral surface 21 of the second outer peripheral surface 21. In the elastic member arranging step, the elastic member 4 is arranged at least in the facing region 221 of the inner peripheral surface 22 of the base material 2 that faces the film forming region 211 of the outer peripheral surface 21 of the base material 2. This will be described in detail below.

  First, when manufacturing the ceramic filter 1 (FIG. 1), as shown in FIG. 2, the porous cylindrical base material 2 was prepared. Specifically, 100 parts by weight of alumina, 10 parts by weight of methyl cellulose, 25 parts by weight of water, and 5 parts by weight of a lubricant were mixed and kneaded with a mixer to obtain a clay for extrusion molding. Then, a cylindrical body having an outer diameter of 14 mm, an inner diameter of 10 mm, and a total length of 300 mm was extruded using an extrusion molding machine and dried by a roller rotary dryer to obtain a cylindrical molded body before firing.

  The obtained cylindrical molded body was fired under conditions of 1600 ° C. and 3 hours in an air atmosphere to obtain a cylindrical fired body. Thereafter, both ends of the cylindrical fired body were excised and polished. As a result, as shown in FIGS. 2A and 2B, a cylindrical substrate 2 having a total length of 200 mm made of porous alumina ceramic was obtained. In the present embodiment, as shown in the figure, the entire outer peripheral surface 21 of the substrate 2 is a film forming region 211 that forms the ceramic separation membrane 3 (FIG. 1).

  Subsequently, as shown in FIG. 3, the elastic member arrangement | positioning process was performed. Specifically, the elastic member 4 made of a cylindrical silicon sponge having an outer diameter of 12 mm was inserted and disposed inside the porous cylindrical base material 2 (inner peripheral surface 22 side). Then, the elastic member 4 is disposed in contact with the facing region 221 of the inner peripheral surface 22 of the base material 2. In the present embodiment, the outer diameter of the elastic member 4 before being arranged inside the base material 2 (before the elastic member arranging step) is larger than the inner diameter of the base material 2. The total length of the elastic member 4 is longer than the total length of the substrate 2.

  Further, the outer peripheral surface 41 of the elastic member 4 inserted and arranged inside the base material 2 is in close contact with the facing region 221 of the inner peripheral surface 22 of the base material 2. Note that the facing region 221 is a region of the inner peripheral surface 22 of the base material 2 that faces the film forming region 211 of the outer peripheral surface 21 of the base material 2 in the radial direction. In the present embodiment, since the entire outer peripheral surface 21 of the substrate 2 is the film forming region 211, the entire inner peripheral surface 22 of the substrate 2 is the opposing region 221. Further, both end portions of the elastic member 4 protrude outward from both ends of the base material 2.

  Next, as shown in FIG. 4, a film precursor forming step was performed. Specifically, the base material 2 with the elastic member 4 disposed inside was immersed in the raw material solution 5. The raw material solution 5 was prepared by mixing 100 parts by weight of alumina having a particle size of 0.35 μm, 1.5 parts by weight of polyacrylate ester, 20 parts by weight of a polyacrylic organic binder, and 200 parts by weight of water. Prepared. The descending speed of the base material 2 was 1 mm / second. And it hold | maintained for 10 minutes in the state in which the base material 2 was immersed in the raw material solution 5 completely. Then, the base material 2 was pulled up from the raw material solution 5 at a pulling rate of 1 mm / second.

  Thereby, as shown in FIG. 5, the film precursor 30 was coated on the film formation region 211 (the entire outer peripheral surface 21) of the outer peripheral surface 21 of the substrate 2. The film precursor 30 is a ceramic porous film before baking formed by depositing alumina fine particles in the raw material solution 5 on the outer peripheral surface 21 of the substrate 2.

  Subsequently, the drying process was performed. Specifically, the film precursor 30 was dried at room temperature for 24 hours in a state where the elastic member 4 was disposed inside the substrate 2 (state shown in FIG. 5). Thereafter, the elastic member 4 was pulled out from the inside of the substrate 2 and removed. In addition, it is preferable that the drying temperature in a drying process shall be less than the boiling point of the solvent of this raw material solution 5 (this embodiment water). This is because if the film is dried at a temperature equal to or higher than the boiling point, the film precursor 30 may be peeled off due to bumping of the solvent.

  Next, a film forming process was performed. Specifically, the base material 2 on which the film precursor 30 was formed was baked under conditions of 1400 ° C. for 2 hours in the air atmosphere, and the film precursor 30 was baked. In addition, although baking temperature changes with ceramic materials, it is about 1000-1600 degreeC normally. Thereby, as shown in FIG. 1, the ceramic separation membrane 3 was formed on the entire outer peripheral surface 21 of the substrate 2, and the ceramic filter 1 was obtained.

Next, the function and effect of this embodiment will be described.
In the method for producing a ceramic filter of the present embodiment, the elastic member 4 is arranged inside the base material 2 in the elastic member arranging step. At this time, the elastic member 4 is placed in contact with the facing region 221 of the inner peripheral surface 22 of the base material 2 that faces the film forming region 211 of the outer peripheral surface 21 of the base material 2. Therefore, when the base material 2 is immersed in the raw material solution 5, the elastic member 4 can suppress the raw material solution 5 from entering the inside of the base material 2. Therefore, when the immersed base material 2 is pulled up from the raw material solution 5, the raw material solution 5 that has entered the inside of the base material 2 forms the opposing region 221 (film formation for forming the film precursor 30) on the inner peripheral surface 22 of the base material 2. The elastic member 4 can suppress backflow from the region 211 to the outside of the substrate 2.

  Thereby, the film precursor 30 formed on the outer peripheral surface 21 of the base material 2 is pushed up and floats by the raw material solution 5 that flows backward from the inside to the outside of the base material 2 when the base material 2 is pulled up. It is possible to suppress the minute bubbles remaining inside from moving to the film precursor 30. And generation | occurrence | production of film | membrane defects, such as a float (peeling), dripping, and a pinhole, of the ceramic separation film 3 formed into a film based on the film | membrane precursor 30 can be suppressed. As a result, the ceramic separation membrane 3 can be accurately formed on the outer peripheral surface 21 of the substrate 2.

  Moreover, in this embodiment, the elastic member 4 is arrange | positioned in the whole inner peripheral surface 22 of the base material 2 at an elastic member arrangement | positioning process. Therefore, the elastic member 4 can enhance the effect of suppressing the intrusion of the raw material solution 5 into the base material 2 and the backflow of the raw material solution 5 from the base material 2 inside. Further, since both end portions of the elastic member 4 protrude outward from both ends of the base material 2, workability when the base material 2 is immersed in the raw material solution 5 can be improved.

  Further, the outer diameter of the elastic member 4 before being arranged inside the base material 2 is larger than the inner diameter of the base material 2. Therefore, in the elastic member arranging step, the elastic member 4 is arranged in close contact with the inner peripheral surface 22 (opposing region 221) of the base material 2. Thereby, the effect which suppresses the penetration | invasion of the raw material solution 5 to the base material 2 inner side and the backflow from the base material 2 inner side of the raw material solution 5 by the elastic member 4 can be heightened.

  In addition, after the film precursor forming step, a drying step of drying the film precursor 30 is performed in a state where the elastic member 4 is disposed inside the base material 2. After the drying step, the elastic member is formed from the inside of the base material 2. 4 is removed. That is, the film precursor 30 before drying may have fluidity and the like. Therefore, by removing the elastic member 4 after drying both the base material 2 and the film precursor 30, before the film precursor 30 is dried, that is, in a state where the film precursor 30 has fluidity and the like. Compared to the case where the elastic member 4 is removed, there is no fear of damaging the film precursor 30 when the elastic member 4 is removed. Thereby, the film | membrane precursor 30 can be accurately formed in the outer peripheral surface 21 of the base material 2, and the film-forming precision of the ceramic separation membrane 3 can be improved.

  Thus, according to the present embodiment, it is possible to provide a method for manufacturing a ceramic filter that can increase the film formation accuracy of the ceramic separation membrane 3. That is, the ceramic filter 1 including the high-quality ceramic separation membrane 3 free from membrane defects can be obtained.

  In this embodiment, water is used as the solvent contained in the raw material solution 5 for ease of handling. However, in order to improve the wettability with respect to the base material 2, an organic solvent may be mixed with the raw material solution 5. Good.

  Moreover, in this embodiment, after immersing the base material 2 in the raw material solution 5, the base material 2 was pulled up from the raw material solution 5 at a pulling speed of 1 mm / sec. The pulling speed of the base material 2 was 0.1 to 30 mm. / Second is preferable, and it is more preferable to set within a range of 0.5 to 10 mm / second. When the pulling rate is less than 0.1 mm / second, the processing time may be long. On the other hand, when the pulling speed exceeds 30 mm / sec, there is a possibility that bubbles in the raw material solution 5 are involved.

  Further, in the present embodiment, the ceramic separation film 3 having a desired film thickness is formed in one film forming process. For example, when a desired film thickness cannot be obtained in one film forming process, It is also possible to adjust the thickening by performing the film forming process a plurality of times. In this case, it is preferable to repeat a series of steps (an elastic member arranging step, a film precursor forming step, and a film forming step) a plurality of times.

  In particular, it is preferable that the ceramic porous film be baked each time a ceramic porous film serving as a film precursor is formed. If an attempt is made to form a ceramic porous film on the ceramic porous film without further baking, the previously formed ceramic porous film is dissolved in the raw material solution, the film surface becomes uneven, and film defects are caused. This is because it may cause it. Further, in order to suppress variations in the film thickness of the ceramic separation membrane 3 in the axial direction of the substrate 2, it is preferable to repeat a series of steps a plurality of times while the substrate 2 is turned upside down.

(Embodiment 2)
The present embodiment is an example in which the type and shape of the elastic member are changed in the ceramic filter manufacturing method.

  As shown in FIG. 6, in the ceramic filter manufacturing method of the present embodiment, in the elastic member arranging step, the elastic member 4 made of a cylindrical silicon tube having an outer diameter of 10.5 mm is inserted and arranged inside the substrate 2. did. Other basic manufacturing methods are the same as those in the first embodiment.

  Also in the case of the present embodiment, the ceramic separation membrane 3 can be accurately formed on the outer peripheral surface 21 of the substrate 2 as in the first embodiment. And generation | occurrence | production of the membrane defect in the ceramic separation membrane 3 can be suppressed. That is, the ceramic filter 1 including the high-quality ceramic separation membrane 3 free from membrane defects can be obtained. Other basic functions and effects are the same as those of the first embodiment.

(Experimental example 1)
In this experimental example, the ceramic separation membrane (ceramic porous membrane) was evaluated for the ceramic filter (Examples 1 and 2) which is an example of the present invention and the ceramic filter (Comparative Example 1) which is a comparative example. .

<Production of Ceramic Filters of Examples 1 and 2>
The ceramic filter of Example 1 was produced by the same method (elastic member: cylindrical silicon sponge) as that of the above-described Embodiment 1. The ceramic filter of Example 2 was produced by the same method (elastic member: cylindrical silicon tube) as in Embodiment 2 described above.

<Preparation of Ceramic Filter of Comparative Example 1>
The ceramic filter of Comparative Example 1 was produced by the same method as in Embodiments 1 and 2 except that no elastic member was used. In the film precursor formation step, the raw material solution was prevented from entering the inside of the base material from the opening portions at both ends in the axial direction of the base material by performing a sealing treatment or the like on the base material.

<Evaluation of ceramic separation membrane>
The maximum pore diameter and film thickness of the ceramic separation membrane (ceramic porous membrane) were measured with respect to a cylindrical ceramic filter having a total length of 150 mm by cutting off both axial ends. The maximum pore size was measured using PoloLux 1000 (Benelux Scientific) according to the valve point method (according to ASTM F316-03). Moreover, the wetting liquid which has perfluoroether as a main component was used for the measuring liquid. The number of samples in Examples 1 and 2 and Comparative Example 1 was 5.

表１にセラミック分離膜の評価結果を示す。

Table 1 shows the evaluation results of the ceramic separation membrane.

  As can be seen from the table, the maximum pore size of the ceramic separation membrane of the ceramic filters of Examples 1 and 2 is 0.2 to 0.3 μm. Since the through-hole distribution of the porous base material is 0.8 to 3.1 μm, the value of the maximum pore diameter is presumed to be the pore diameter derived from the ceramic separation membrane.

  On the other hand, some ceramic separation membranes of the ceramic filter of Comparative Example 1 have a maximum pore diameter value that matches the through-hole distribution of the substrate. This is presumably because a membrane defect has occurred in the ceramic separation membrane, and the hole diameter of the through hole of the base material has been detected.

  Thus, according to the manufacturing method of the ceramic filter of this invention, it turned out that the film-forming precision of a ceramic separation membrane (ceramic porous membrane) can be improved, and generation | occurrence | production of a membrane defect can be suppressed. That is, it was found that a ceramic filter provided with a high-quality ceramic separation membrane (ceramic porous membrane) free from membrane defects was obtained.

(Embodiment 3)
The present embodiment is an example in which the type of ceramic separation membrane is changed in the method for manufacturing a ceramic filter. Hereinafter, description will be made with reference to FIGS.

  As shown in FIG. 1, in the ceramic filter 1 manufactured by the method for manufacturing a ceramic filter of the present embodiment, the ceramic separation membrane 3 is a zeolite membrane. Other basic configurations are the same as those in the first embodiment.

  Moreover, in the method for manufacturing a ceramic filter of the present embodiment, a porous cylindrical base material 2 was prepared as shown in FIG. Subsequently, as shown in FIG. 3, the elastic member arrangement | positioning process was performed. Specifically, the elastic member 4 was inserted and arranged inside the porous cylindrical base material 2.

  Next, as shown in FIG. 4, a film precursor forming step was performed. Specifically, the base material 2 with the elastic member 4 disposed inside was immersed in a slurry-like raw material solution 5 in which zeolite seed crystals were dispersed in pure water, and then pulled up from the raw material solution 5. Thereby, the zeolite seed crystal as the film precursor was adhered to the film forming region 211 (the entire outer peripheral surface 21) of the outer peripheral surface 21 of the base material 2.

  Subsequently, the drying process was performed. Specifically, the zeolite seed crystal as the membrane precursor was dried at 80 ° C. in a state where the elastic member 4 was disposed inside the substrate 2. Thereafter, the elastic member 4 was pulled out from the inside of the substrate 2 and removed.

  Next, a film forming process was performed. Specifically, the base material 2 on which the film precursor (zeolite seed crystal) was adhered was immersed in a predetermined synthetic solution placed in a pressure vessel (not shown). And the pressure-resistant container was left still in a 150 degreeC high temperature dryer, and hydrothermal synthesis was performed. As the synthesis solution, an aqueous solution having a uniform composition was used, for example, an Si element source, an Al element source, and an aqueous solution containing an organic template or an alkali source called a structure directing agent as necessary.

  Next, the pressure vessel was cooled to room temperature, and the substrate 2 was taken out from the pressure vessel. Then, the substrate 2 was washed with water and dried. Thereby, as shown in FIG. 1, the ceramic separation membrane 3 (zeolite membrane) was formed on the entire outer peripheral surface 21 of the substrate 2, and the ceramic filter 1 was obtained. Other basic manufacturing methods are the same as those in the first embodiment.

  Also in the case of the present embodiment, the ceramic separation membrane 3 (zeolite membrane) can be accurately formed on the outer peripheral surface 21 of the substrate 2 as in the first embodiment. And generation | occurrence | production of the membrane defect in the ceramic separation membrane 3 can be suppressed. That is, the ceramic filter 1 including the high-quality ceramic separation membrane 3 free from membrane defects can be obtained. Other basic functions and effects are the same as those of the first embodiment.

(Experimental example 2)
In this experimental example, the ceramic separation membrane (zeolite membrane) was evaluated for the ceramic filter (Example 3) as an example of the present invention and the ceramic filter (Comparative Example 2) as a comparative example.

<Preparation of Ceramic Filter of Example 3>
The ceramic filter of Example 3 was produced by the same method (elastic member: cylindrical silicon sponge) as that of the above-described Embodiment 3.

<Preparation of Ceramic Filter of Comparative Example 2>
The ceramic filter of Comparative Example 2 was produced by the same method as in Embodiment 3 except that no elastic member was used. In the film precursor formation step, the raw material solution was prevented from entering the inside of the base material from the opening portions at both ends in the axial direction of the base material by performing a sealing treatment or the like on the base material.

<Evaluation of ceramic separation membrane>
The pervaporation separation evaluation was performed on the ceramic separation membrane (zeolite membrane) of the produced ceramic filter. Permeate vaporization separation evaluation calculates the separation factor by measuring the purity of water on the permeate side when the permeate side is depressurized to 2 kPa using a 90% ethanol and 10% water mixture as the feed liquid. Compared. The separation factor can be obtained from the equation (water amount of permeate / ethanol amount of permeate) / (water amount of feed solution / ethanol amount of feed solution).

  When the above-described pervaporation evaluation was performed, the separation factor of the ceramic separation membrane of Example 3 was 2200, whereas the separation factor of the ceramic separation membrane of Comparative Example 2 was 150. This is presumed that a membrane defect occurred in the ceramic separation membrane of Comparative Example 2 and ethanol could not be sufficiently separated.

  Thus, according to the manufacturing method of the ceramic filter of this invention, it turned out that the film-forming precision of a ceramic separation membrane (zeolite membrane) can be improved, and generation | occurrence | production of a membrane defect can be suppressed. That is, it was found that a ceramic filter provided with a high-quality ceramic separation membrane (zeolite membrane) free of membrane defects was obtained.

(Other embodiments)
It goes without saying that the present invention is not limited to the above-described embodiment, and can be implemented in various modes without departing from the present invention.

  (1) In the said embodiment, as shown to FIG. 2 (a), (b), although the base material 2 which consists of porous alumina was used, it is not limited to this, For example, FIG. As shown in a), as the substrate 2, a substrate 2 having a support 2a made of ceramic such as porous alumina, and a porous intermediate film 2b formed on the outer peripheral surface of the support 2a. It may be used. Then, as shown in FIG. 7B, a ceramic filter 1 in which a ceramic separation membrane 3 is formed on a base material 2 constituted by a support 2a and an intermediate membrane 2b may be used. Note that the intermediate film 2b is, for example, for improving the adhesion with the ceramic separation film 3, and may be a single layer as shown in FIG. 7A or a plurality of layers.

  (2) In the embodiment, as shown in FIGS. 2A and 2B, the entire outer peripheral surface 21 of the base material 2 is the film formation region 211. For example, FIG. 8A and FIG. As shown in FIG. 3, a part of the outer peripheral surface 21 of the base material 2 may be the film forming region 211. In the example shown in the figure, the portion (the region between the dotted lines) excluding both end portions on the outer peripheral surface 21 of the base material 2 is the film forming region 211.

  Moreover, in the said embodiment, as shown to FIG. 2 (a), (b), although the whole internal peripheral surface 22 of the base material 2 is the opposing area | region 221, for example, to FIG. 8 (a), (b) As shown, a part of the inner peripheral surface 22 of the substrate 2 may be a facing region 221. In the example shown in the figure, a portion (a region between dotted lines) excluding both end portions on the inner peripheral surface 22 of the base material 2 is the facing region 221.

  (3) In the embodiment, in the elastic member arranging step, as shown in FIG. 3, at least the facing region 221 of the inner peripheral surface 22 of the base material 2 that faces the film forming region 211 of the outer peripheral surface 21 of the base material 2. The elastic member 4 is disposed on the surface. Therefore, for example, as shown in FIG. 9 (a), the elastic member 4 may be disposed only in the facing region 221 of the inner peripheral surface 22 of the base member 2, or as shown in FIG. 9 (b). The elastic member 4 may be disposed up to the opposing region 221 of the inner peripheral surface 22 of the material 2 and the region outside (outside the dotted line).

  (4) In the embodiment, in the elastic member arranging step, the elastic member 4 is arranged on the entire inner peripheral surface 22 of the base member 2 as shown in FIG. 3, but for example, as shown in FIG. As described above, the elastic member 4 may be disposed on a part of the inner peripheral surface 22 of the substrate 2.

  (5) In the said embodiment, in the elastic member arrangement | positioning process, as shown in FIG. 3, in the state which has arrange | positioned the elastic member 4 inside the base material 2, both ends of the elastic member 4 are outside from the both ends of the base material 2. For example, as shown in FIGS. 9A and 9B, both end portions of the elastic member 4 may be prevented from protruding outward from both ends of the base material 2.

  (6) In the first embodiment, in the elastic member arranging step, as shown in FIG. 3, the elastic member 4 made of a solid silicon sponge is inserted and arranged inside the base material 2. Moreover, in the said Embodiment 2, as shown in FIG. 6, the elastic member 4 which consists of a cylindrical silicon tube is inserted and arrange | positioned inside the base material 2 in the elastic member arrangement | positioning process. That is, the shape and structure of the elastic member 4 are not particularly limited as long as the elastic member 4 can be brought into close contact with the facing region 221 of the inner peripheral surface 22 of the base material 2 without damaging the base material 2. It may be solid or cylindrical, or may be hollow like a rubber balloon.

  (7) In the embodiment, the elastic member 4 is removed from the inside of the base material 2 after the drying step. However, the elastic member 4 is disposed on the base material 2 when the base material 2 is immersed and pulled up. It is sufficient that it is removed from the substrate 2 during the film forming step.

DESCRIPTION OF SYMBOLS 1 ... Ceramic filter 2 ... Base material 21 ... Outer peripheral surface 211 ... Membrane formation area 22 ... Inner peripheral surface 221 ... Opposite area | region 3 ... Ceramic separation membrane 30 ... Membrane precursor 4 ... Elastic member 5 ... Raw material solution

Claims (4)

A method for producing a ceramic filter formed by forming a ceramic separation membrane on the outer peripheral surface of a porous cylindrical substrate,
An elastic member arranging step of arranging an elastic member having elasticity inside the base material;
A film precursor forming step of immersing the base material in which the elastic member is disposed in a raw material solution containing the raw material of the ceramic separation membrane, and forming a film precursor in a film forming region on the outer peripheral surface of the base material When,
A film forming step of forming the ceramic separation film from the film precursor formed in the film forming region of the outer peripheral surface of the base material,
In the elastic member disposing step, the elastic member is disposed at least in an opposing region of the inner peripheral surface of the base material that opposes the film forming region of the outer peripheral surface of the base material. Production method.   The method for producing a ceramic filter according to claim 1, wherein, in the elastic member arranging step, the elastic member is arranged on the entire inner peripheral surface of the base material.   3. The method of manufacturing a ceramic filter according to claim 1, wherein an outer diameter of the elastic member before being arranged inside the base material is larger than an inner diameter of the base material.   After the film precursor forming step, a drying step of drying the film precursor is performed in a state where the elastic member is disposed on the inner side of the base material. After the drying step, the elasticity is applied from the inner side of the base material. The member is removed, The manufacturing method of the ceramic filter of any one of Claims 1-3 characterized by the above-mentioned.

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