JPH11292651A - Zeolite-forming porous body and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a porous body excellent in mechanical strength and having requirement necessary as a carrier by forming into a porous body having a porous zeolite layer on the surface of porous ceramic substrates and the surface of internal pores provided with internal pores having specific pore diameter and porosity and having a specific pressure break strength. SOLUTION: This zeolite-forming porous body is equipped with hollow pores having large diameter, small-size communicating pores for making hollow pores communicate with each other and internal pores having hollow pores and small- size communicating pores communicating with the outside, and a substrate in which a circle pore diameter corresponding to center value of volume accumulation of communicating pores having 1-360 μm pore diameter is 40±25 μm and that of the communicating pores having 5-1,100 μm pore diameter is 320±150 μm and inside diameter and internal shape in the internal pores composed of the hollow pores and communicating pores are irregular and porosity of pores having >=20 μm pore diameter among porosity of internal pores having 1-360 μm pore diameter is >=20 wt.% and the pressure break strength is >=5 MPa is used as the substrate. The zeolite layer is formed by heating the substrate in an alkali solution.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION Zeolite can be used, for example, as a molecular fraction sieve, an ion exchange agent, a catalyst carrier, or a catalyst functional agent by itself. Furthermore, because of its ion exchange ability, it has a high ability to adsorb microorganisms or metabolites such as ammonia, and is used as a carrier for microorganisms and enzymes such as bioreactors used in the bioreactor of food industry or biochemical treatment of wastewater. Is also useful.

The field of the present invention is, for example, a flow path having a pore size of several μm or more according to the purpose of use, which is installed in a fluid such as a liquid or a gas. This is a field in which zeolite is used as a porous body having a spherical shape or an arbitrary shape having a low mass transfer resistance and improving the reaction efficiency of the entire porous body.

[0003]

2. Description of the Related Art The following methods are known as examples of known methods for producing massive zeolites. A product formed from a powder obtained by converting zeolite of coal ash or other particles of several μm to several tens μm into a starting material, such as granules or plates.

A porous support in which pores are filled with zeolite and hermetically sealed (only a few tens of strokes to several tens of Angstrom pores of the zeolite are secured as a fluid flow path). One in which zeolite is formed on a monolithic support having regular flow passage holes of 100 μm or more, which is formed by an extruder or the like (see Japanese Patent Application Laid-Open No. 1-148771). The following conditions may be mentioned as necessary conditions for the conditions of the porous body to be performed.

(1) Flow resistance is small. (2) No spilled dust. (3) Work such as rejuvenation (regeneration) should be easy.

[0006]

However, conventional porous bodies have advantages and disadvantages as described below, and it is difficult to industrially produce those satisfying all of the above requirements.
It was virtually difficult. As for the subject shown in <Problem 1>, molding is performed by mixing water glass, clay, and other similar substances as a binder because the zeolite powder is difficult to mold, but the zeolite activity of the molded article is reduced by the mixed powder. Further, when a heat treatment is performed to improve the strength of the molded article, if the treatment is performed at a high temperature, the strength increases, but the zeolite activity of the molded article also decreases.

In the case of <Problem 2>, although the strength is ensured by the support, the flow path is extremely small and the flow path resistance is extremely large. This is a production method limited to fields where flow path resistance does not matter, such as molecular sieves. <Problem 3> The invention also relates to an invention in which a honeycomb monolithic ceramic porous body having regular linear porosity is used as a support.
It cannot be applied to spherical products of 0.5 to 10 [mm].

[0008]

Means for Solving the Problems (1) That is, in order to achieve the above object, the invention of claim 1 is characterized in that the porous ceramic substrate subjected to the zeolite treatment has a large diameter formed inside. A large number of internal holes having a cave hole, a small-diameter communication hole communicating the cave holes with each other, and a small-diameter communication hole communicating the cave hole with the outside are provided.
(V) the condition of (a) is satisfied, and (i) the circular hole diameter equivalent to the median of the integration of the communication hole volumes of the hole diameters of 1 to 360 [μm] is 40 ± 25 [μm]; (Ii) Hole diameter 5
(Iii) the diameter of a hole corresponding to the median value of the integrated area of the cave holes of １1100 [μm] is 320 ± 150 [μm];
The internal hole composed of the hole and the communication hole has an irregular shape in which the inner diameter and the internal shape are changed irregularly, and (iv) the hole diameter is 1 to 360 [μm]. Among the porosity of the internal pores, the porosity having a pore diameter of 20 [μm] or more is 20 [%] or more, (v) the compressive fracture strength is 5 [MPa] or more, and the above conditions are satisfied. The essence of the present invention is a zeolite-containing porous body characterized by having a porous zeolite layer on the surface of the porous ceramic substrate and the surface of the internal pores.

Here, as shown schematically in FIGS. 1 and 2, the zeolite-formed porous body of the present invention is based on a porous basic structure (porous ceramic) mainly composed of, for example, silica and alumina. Base) and a zeolite layer on the surface (zeolite layer),
Among them, the structure of the porous ceramic substrate and the method for producing the same are the same as those described in Japanese Patent Application No. 4-31819 (however, the application is not limited to those for growing microorganisms).

Next, the characteristics of the zeolite-formed porous body will be described. FIG. 1 is an explanatory view schematically showing, for example, the entire cross section of a spherical carrier. FIG. 2 (A) is an enlarged view of a main part thereof, and FIG. It is shown 90 degrees differently as seen from.

The zeolite layer usually covers the apparent surface (hereinafter abbreviated as the outer surface) of the porous ceramic substrate and also covers the hole wall surface of the inner hole (hereinafter abbreviated as the inner surface). However, some parts may not be covered depending on the purpose of use. The thickness of this zeolite layer may be within a range that does not cause a decrease in the strength of the porous ceramic substrate and does not block the internal holes very much. For example, a thickness of 1 to 100 [μm] can be adopted.

The median hole diameter equivalent to the median value of the integrated communication hole volume in (i) was obtained by a porosimeter method (the measurement limit was a mercury intrusion porosimeter having a large pore diameter of 360 [μm]. Value) is desirable. The diameter of the circular hole corresponding to the median value of the integration of the dented hole area in the above (ii) is preferably obtained by an image processing method for a cross section of a porous body.

In particular, a combination of a communication hole having a hole diameter of 40 [μm] and a cave hole having a hole diameter of 320 [μm] as close as possible is preferable because of, for example, excellent reactivity with microorganisms. Of the porosity of the pores having a pore diameter of 1 to 360 [μm] in the above (iv), if the porosity of the pores having a pore diameter of 20 [μm] or more is 20 [%] or more, for example, the propagation of microorganisms and Suitable for the reaction by the microorganism, but especially 4
Desirably, the value is 0% or more.

The compressive breaking strength of (v) is 5 [MP
a] or more, sufficient strength can be ensured in the zeolite porous body used for various applications. (2) The invention of claim 2 is characterized in that the zeolite-made porous body has a compressive breaking strength of 5 [MPa] or more.

That is, as the zeolite-made porous body,
A material having a compressive breaking strength of 5 [MPa] or more is desirable because it is less likely to be damaged in actual use and has excellent durability, but a material having a compressive strength of 7 [MPa] or more is more preferable. The zeolite-made porous body having pores satisfying the following conditions is suitable for, for example, various carriers.

(I) The porosity is 20% or more due to the pore diameter of 0.5 to 1 μm or more. (3) The invention of claim 3 provides the effective use depth according to the purpose of use on the surface side of the zeolite porous body. (E.g., the thickness of the effective reaction zone shown in FIG. 1), and an inner layer portion is provided inside the outer layer portion, and the outer layer portion has the irregularly shaped porosity and is not effectively used. It is characterized by having no porosity in the inner layer portion.

Here, the effective use depth is described as follows.
For example, the reaction proceeds in the depth direction of the porous body with the base concentration in the external fluid, and the concentration decreases. If the concentration is almost zero, the deeper places become invalid pores or dead spaces irrelevant to the reaction, A pore portion shallower than that has a depth effective for the reaction (that is, an effective utilization depth). Alternatively, in the microbial reaction, the depth of the inhabiting bacteria is referred to as the effective use depth.

In the structure of the porous ceramic substrate, the internal pores defined in claim 1 may be formed over the entire inside of the porous ceramic substrate, but may be formed only in the surface side layer. Is also good. In addition, particularly when the shape of the porous ceramic substrate is spherical, when the central layer is deeper than the effective use depth, the porosity of the central layer is smaller than that of the outer surface layer, or even if it is non-porous. Good.

(4) The invention of claim 4 is characterized in that the porous zeolite body is used as a carrier. (5) The invention according to claim 5, wherein the zeolite-formed porous body is
It is a carrier for growing microorganisms.

(6) The invention according to claim 6 is characterized in that, when the porous ceramic substrate having the configuration of (a) is manufactured,
When a ceramic material powder containing 20% by weight or more of a raw material having a large particle diameter of 20 μm or more is formed, and then fired at 1150 to 1450 ° C., in a firing temperature range of 1000 ° C. or less, a structure having no pores of 5 μm or more is fired. The eutectic nucleus partially starts with the rise in temperature and the elapsed time, the quantity of the cohesion nuclei and the cross-linking part between the nuclei both increase quantitatively, and the eutectic cohesion nuclei progress from small pores to large pores It is characterized by using a method for producing a crosslinked porous ceramic.

Here, a method for producing a eutectic agglomeration nucleus crosslinked porous ceramics, which is a method for producing a porous ceramic substrate as a basic structure, will be briefly described. This method has already been proposed by the present inventors in Japanese Patent Application Nos. 3-105947 and 4-116358. That is, as a material component shown in the glaze type, an acidic component RO
₂ , the neutral component R ₂ O ₃ , the alkaline earth component RO, and the alkaline component R ₂ O are in a molar ratio in a range satisfying the following formulas (1) to (6) or in the following formulas (5) and (6). With the determined blending coordinate point (X, Y) as the center, it is used within the range of a circle having a radius r represented by the following equation (7), and the neutral component R ₂ O _{3 is used.}
And the content of the alkaline earth component RO having a raw material particle diameter of 40 μm or more is 40 to 7 μm.
0 <% by weight, 1.2 <θ <1.45 (where θ = t ° C. × 1
0 ^-3) process for producing a porous ceramic substrate and firing in the range of firing temperature t satisfying, that is, the preparation of the eutectic aggregation nuclei crosslinked porous ceramics.

X = RO ₂ / (RO + R ₂ O) (1) Y = R ₂ O ₃ / (RO + R ₂ O) (2) Z = R ₂ O / (RO + R ₂ O) (3) Z = 2.311 × 10 ⁵ × exp (−12.28 × θ) ± exp (−3.8 × θ) (4) Y ₁ <Y <Y ₂ (5) where Y ₁ = X−1.75 , Y ₂ = X + 0.75 Y = −X + A (θ) (6) where A (θ) = 5808.75 × {1-exp (−6.72 × θ)} − 585.07 r = {A ( θ + 0.05) −A (θ)｝ / 2 ^1/2 (7) In this production method, the range of the particle diameter of the raw material for the neutral component R ₂ O _{3 and} the particle diameter of the raw material for the alkaline earth component RO And the range of the weight% and the firing temperature t,
The ranges of the component ratios of X, Y, and Z (consisting of an acidic component RO ₂ , a neutral component R ₂ O ₃ , an alkaline earth component RO, and an alkaline component R ₂ O) represented by the respective formulas (7) are as follows: Both are determined by experiments, and within this range, a good porous ceramic can be formed.

The R in the glaze is an oxide component usually used in the ceramic industry, for example, Si, Z
r, Al, Fe, Ca, Mg, Na, K and the like. Therefore, as the acidic component RO ₂ , for example, SiO ₂ ,
Examples of ZrO ₂ and the neutral component R ₂ O ₃ include Al ₂ O ₃ ,
Fe ₂ O ₃ and the alkaline earth component RO include, for example, Ca
Examples of O, MgO and alkali component R ₂ O include Na ₂
O, K ₂ O, etc. can be used respectively.

(7) The invention according to claim 7 is characterized in that the mixed raw material powder (A) used in the production of the porous ceramic substrate having the constitution of (a) is a plant powder, a synthetic resin powder, coal or coke. A component (B) to be removed in a subsequent step, such as powder and salts, is mixed at a ratio of (A) / (B) = 20 to 1,
Due to the residual holes caused by the removal substance (B) after firing,
It is characterized in that the porosity of a predetermined pore diameter is further increased by the particle size of the substance to be removed (B), and at the same time, the total porosity is also increased.

The removal substance (B) used here includes:
A material that is as hard as possible is desirable so that it is not compressed into fine particles during molding or the like, or it is not difficult to maintain the shape of the molded product due to expansion or other factors during the manufacturing process. In addition, the term “after the firing” refers to the time after the main firing when the main firing is performed after the temporary firing, and the case where only the main firing is performed without the temporary firing indicates the time after the main firing.

(8) The invention of claim 8 is to form a zeolite layer on the surface of the porous ceramic substrate by heating the porous ceramic substrate having the structure of (a) in an alkaline solution. It is characterized by doing.

Here, as the alkaline solution, for example, an aqueous solution of sodium hydroxide, potassium hydroxide or the like can be employed. The concentration may be in the range of 0.8 to 5 s. Furthermore, as the heating temperature, a range from room temperature to 300 ° C. can be adopted.

(9) A ninth aspect of the present invention is a porous ceramic substrate mainly composed of silica and alumina, wherein a large-diameter hole formed therein, and a small-diameter communication hole communicating the holes are provided. Using a porous ceramic substrate having many internal holes having a small diameter communication hole communicating the cave hole and the outside and satisfying the following conditions (i) to (iii), (b) (I) that the internal hole formed by the cave hole and the communication hole has an irregular shape in which the inner diameter and the internal shape are changed irregularly;
i) Among the porosity of the internal pores having a pore diameter of 1 to 360 [μm], the porosity having a pore diameter of 20 [μm] or more is 20 [%] or more; (iii) compressive fracture strength Is not less than 5 [MPa], and the porous ceramic substrate is heated in an alkaline solution to form a porous zeolite made of zeolite on the outer surface and the inner pore surface of the porous ceramic substrate. Forming a layer.

(10) The tenth aspect of the present invention is characterized in that a template agent for selectively generating zeolite is added to the alkaline solution. The template agent is an additive for assisting the formation of a specific type of zeolite, and for example, an organic mold removing agent such as tetrapropylammonium bromide can be used.

(11) The invention of claim 11 is characterized in that the concentration of the alkaline solution is changed during the processing step. (12) The invention of claim 12 is characterized in that the heating is performed in the atmosphere.

(13) A thirteenth aspect of the present invention is characterized in that the heating is performed in an autoclave in a pressurized state.

[0032]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Regarding a specific example of a porous ceramic substrate which is a basic structure of the constitution of the present invention, for example, the description of Japanese Patent Application No. Since it is described in detail as "porous ceramics produced by a method for producing coagulated nucleus crosslinked porous ceramics", here, a zeolite-made porous body having a zeolite layer on the surface of a porous ceramic substrate and the surface of internal pores is described. Details will be described.

(1) In the first to fifth aspects of the present invention, a zeolite layer is formed on the surface of the porous ceramic base material (having a large number of internal pores satisfying predetermined conditions) and the surface of the internal pores as the basic structure. Are formed. In this zeolite layer, extremely fine pores having a zeolite crystal structure (for example, pores having a diameter of several angstroms to several tens angstroms) and micropores of a tissue gap (several nanometers to several micrometers) are formed on one surface. Therefore, in the present invention, it is possible to exhibit performance such as zeolite adsorbability, ion exchange property, catalytic property, molecular sieve property, etc. while having a unique internal pore structure of the porous ceramic substrate as the basic structure. It will also have micropores and micropores. Thereby,
Compared to the case of a normal carrier in which a zeolite layer is simply formed on the outer surface, in the present invention, the treatment operation is performed to such an extent that the communication hole of several tens of micrometers or more of the basic structure is not blocked. By performing, at least 0.5 to 1
Since there are communication pores of micrometers or more, and then micropores due to the zeolite structure gap described above, and then ultrafine pores having a zeolite crystal structure, mass transfer resistance to the deep part of the zeolite porous material is small, The mass transfer to the whole body is fast and therefore the reaction efficiency is improved. Due to this, the above-mentioned zeolite adsorptivity,
Performances such as ion exchange property, catalytic property, molecular sieve property and the like are further exhibited.

Further, in the present invention, for example, silica and alumina are preferable as the main substances constituting the porous ceramic substrate. According to the second aspect of the present invention, since the zeolite-made porous body has a compressive breaking strength of 5 [MPa] or more, it has excellent durability.

According to the third aspect of the present invention, the outer surface of the zeolite porous body is provided with an outer layer portion having an effective use depth according to the purpose of use, and the outer layer portion has irregularly shaped porosity. Therefore, it effectively acts on, for example, the growth of microorganisms. As described above, for example, in a carrier for growing microorganisms, even when pores are formed from the surface to the inside of the carrier, the fact that microorganisms are actually attached and it is easier for them to grow is
Usually, near the surface of the carrier where nutrients and the like are easily secured, as a result, the bacterial concentration becomes high near the surface. Therefore, the range in which the microorganisms can actually adhere and inhabit and reproduce is the effective use range. This is true even when used as a carrier for a catalyst or the like. The fact that substances around the carrier can participate in the reaction (depending on the inner diameter of the pores and the viscosity of the fluid) is based on the concept of the catalyst effective coefficient. As shown in the above, it is usually easy to be limited to near the surface of the carrier.

According to the fourth aspect of the present invention, the porous zeolite is used as a carrier for carrying various functional substances such as a catalyst and an enzyme. In the invention of claim 5, the zeolite-formed porous body is used as a carrier for growing microorganisms. In particular, in the case of the zeolite-formed porous body having a communication hole diameter of 20 micrometers secured in the present invention, in addition to having the internal holes having the above-described configuration, the internal surface as well as the external surface is covered with the zeolite layer, It has excellent ability to attach and grow microorganisms.

In particular, zeolite has a cation exchange property as described above, adsorbs and removes substances such as ammonia which deteriorate the growth environment of microorganisms, and removes negatively charged microorganisms from the porous ceramic body. From these points, the zeolite-based porous body of the present invention is in a state suitable for the propagation of microorganisms, and the growth of microorganisms is promoted.

The invention of claim 6 exemplifies a method of manufacturing a porous ceramic substrate. That is, the porous ceramic substrate having the configuration (a) can be easily manufactured by the above-mentioned “method of manufacturing the eutectic aggregation nucleus crosslinked porous ceramics”. The invention of claim 7 more specifically exemplifies a method of manufacturing a porous ceramic substrate.

That is, the mixed raw material powder (A) for producing the porous ceramic substrate according to claim 7 is preferably removed in a subsequent step such as hard plant powder, synthetic resin powder, coal, coke powder, and salts. (A) /
(B) = 20 to 1 are mixed, and the amount of pores having a predetermined pore diameter is increased by the particle size of the removed substance (B) due to the residual pores caused by the removed substance (B) after firing, and at the same time, The overall porosity can also be increased.

According to this production method, a porous ceramic substrate, which is a basic structure having predetermined internal pores, can be formed. By forming a zeolite layer on the surface, the zeolite-formed porous body of the present invention can be produced. can do. In the invention of claim 8, for example, a zeolite layer can be formed on the surface of the porous ceramic substrate by heating the porous ceramic substrate mainly composed of alumina and silica in an alkaline solution.

That is, for example, by heating a porous ceramic substrate mainly composed of silica and alumina in an alkaline solution, the silica and alumina become
It reacts on the outer surface of the porous ceramic substrate and the surface of its internal pores, and recrystallizes as zeolite. That is, a thin (for example, a thickness of about 1 to 40 [μm]) zeolite layer is formed on the inner and outer surfaces of the porous ceramic substrate by heating under conditions in which zeolite crystals are formed.

The reason why the alkali solution is used here is that the alkali solution reacts with the porous ceramic base component to generate zeolite. The zeolite synthesis method by the hydrothermal method is a known method. is there. According to the ninth aspect of the present invention, the porous ceramic substrate is not manufactured by the “method of manufacturing a eutectic agglomeration nucleus crosslinked porous ceramic” according to the sixth aspect, but the porous ceramic substrate having the configuration of the above (a) is used. By forming a zeolite layer on the surface of the ceramic substrate or the surface of the internal pores using the ceramic substrate, for example, it can be suitably used as a carrier for microbial growth and the like, and a porous zeolite body can be produced.

According to the tenth aspect of the present invention, selective nucleation of a specific type of zeolite is promoted by adding a template agent to an alkaline solution. According to the eleventh aspect, by changing the alkali concentration during the heating step, a zeolite species different from that of the eighth aspect can be generated, and the ion exchange amount can be increased.

According to the twelfth aspect of the present invention, since the heating for forming the zeolite is performed in the atmosphere, it is possible to simplify the apparatus configuration in the zeolite forming process. In the invention of claim 13, the heating at the time of forming the zeolite,
Since it is performed in an autoclave in a pressurized state, there is an advantage that conditions can be easily set and the thickness and the like of zeolite can be adjusted.

[0045]

EXAMPLES Examples of the porous zeolite body (hereinafter, also referred to as zeolite porous ceramics: ZPC) of the present invention and a method for producing the same will be described below. (1) Example 1 (Manufacture of ZPC at atmospheric pressure) In this example, first, a spherical porous ceramic substrate was manufactured as a precursor, and this was heated in an alkaline solution at atmospheric pressure. Porous body (Zeolite Porous Ceramics: ZPC) with a new zeolite layer formed on the surface of the porous ceramic substrate and the surface of the internal pores
Was manufactured. 1. Porous ceramic substrate 1.1 Manufacturing method of porous ceramic substrate Ceramic raw material No. 1 having the composition (% by weight) as shown in Table 1 below
Sample Nos. A1 to A7 were prepared by mixing them, and mixing them to obtain the molar ratios of X, Y, and Z and the particle diameters of the raw materials shown in Table 2 below.
A5 was prepared.

[0046]

[Table 1]

[0047]

[Table 2]

Next, spherical porous ceramic substrates are prepared using the prepared sample Nos. A1 to A5. Typical examples are (No. B1 to B5: the raw material is the sample A).
No. (corresponding to the No.) is exemplified. First, spheres having a diameter of 2 to 6 mm were formed using a tumbling granulator mainly using water as a binder. Sample Nos. A1 to A3 were granulated at a high pressure, while Sample Nos. A4 and A5 were set to about 1/5 of the pressure of Sample Nos. A1 to A3.

The sphere was fired with a heating time of 15 hours and a firing temperature holding time of 5 hours. The firing temperature differs depending on the composition of the sample. Sample Nos. A1, A2 and A5
The gas was fired at 1350 ° C. in a high temperature range (1300 to 1400 ° C.) using a gas furnace having a furnace inner volume of 0.35 m ³ . On the other hand, for sample Nos. A3 and A4, a gas furnace having a furnace inner volume of 2 m ³ was used, and 12 ° C. in a low temperature range (1200 to 1300 ° C.) was used.
It was baked at 50 ° C.

After the firing, the fire was extinguished and the furnace was cooled. A few hours later, the red sphere at about 800 ° C. was withdrawn into the atmosphere, cooled at a higher cooling rate, and then cooled to a sample No. A1.
Nos. B1 to B5 respectively corresponding to Nos. To A5 were obtained. Incidentally, the porous ceramic substrates of Nos. B1 to B5 are mainly composed of silica and alumina, and are accordingly porous ceramic substrates containing calcia and magnesia. 1.2 Structure and Properties of Porous Ceramics Substrate 1.2.1 Porosity and Strength of Porous Ceramics Substrate First, the porosity of each sample was measured using a mercury intrusion porosimeter (Autopore 9220, manufactured by Microlitix, USA).
Was measured by The compressive breaking strength was examined by a universal testing machine (manufactured by Tokyo Koki Co., Ltd .: particles were placed between flat plates and pressurized, and the maximum breaking force was divided by the projected area of the particles to obtain the compressive breaking strength). The results are shown in Table 3 below.

[0051]

[Table 3]

Compressive breaking strength [MPa] = Compressive breaking load by plate [N] / projected area of particles [m ² ] As is clear from Table 3, spherical particle samples No. B1 to B
5, most of the formed holes are larger than 20 μm or more, and the surface aperture ratio is moderately large.
Further, many large communication holes are formed inside.

Further, in the case of a pore diameter of 1 to 360 [μm],
Circular hole diameter equivalent to the median of the integrated communication hole volume is 40 ± 25.
[Μm]. According to this measurement, the porosity of the pore having a pore diameter of 20 to 360 [μm] is 2
It turned out that it is 0 [%] or more.

Further, the strength of the porous ceramic substrate is as follows:
It turned out that it is 9 [MPa] which greatly exceeds 5 [MPa]. 1.2.2 Structure of Porous Ceramic Substrate Next, the structure of the porous ceramic substrate was examined using a scanning electron microscope.

FIGS. 3 and 4 show scanning electron micrographs of the porous ceramic substrate. The porous ceramic substrate has a large-diameter hole formed therein and a small-diameter communicating hole communicating with the den-hole. It was found that the porous body was composed of irregular holes composed of small-diameter communication holes that communicate the holes, caves, and the outside.

FIG. 3 is a scanning electron micrograph of the surface of the porous ceramic substrate produced by the eutectic aggregation nucleus crosslinking method, and FIG. 4 is a view of the porous ceramic substrate produced by the eutectic aggregation nucleation crosslinking method. It is a scanning electron microscope photograph of a fracture surface. Next, the scanning electron micrograph of the cross section of the porous ceramic substrate was analyzed by a computer-based image processing method, and the hole diameter of the cave hole was analyzed.

As a result, the circular hole diameter equivalent to the median value of the cumulative pore area of the pore diameter of 5 to 1100 [μm] was 320 ± 150.
[Μm]. 1.3 Effect of Porous Ceramic Substrate As described above, the porous ceramic substrate used in the present example is provided with the above-described internal hole composed of the cave hole and the communication hole, so that the carrier having excellent microbial reactivity is provided. And has high strength. In other words, as a substrate of a carrier that supports microorganisms, the microorganisms easily adhere to the inside thereof, and are provided with a large space in which the microorganisms can propagate, and are extremely excellent in reactivity (as indicated by the reaction rate). . In addition, since it has a high compressive strength, it is resistant to cracking and abrasion, and has excellent durability. Due to these properties, the porous ceramic substrate can be used not only as a carrier for microorganisms, but also for various functions, retention of substances, adsorption, liquid absorption, etc. It can be expected to improve the performance. 2. 2. Zeolite Porous Ceramics (ZPC: Production under Atmospheric Pressure) 2.1 Zeoliteization of Porous Ceramics Substrate (Atmospheric Pressure) First, one of the porous ceramics substrates (for example, No. 20 g of a porous ceramic substrate (B1) was weighed, and 160 ml of an aqueous sodium hydroxide solution (concentration: 3.5 N) was added thereto. Then, a cooling tube was attached to the mouth of the flask, and the mixture was heated at 95 ° C. for 24 hours while stirring with a hot stirrer.

In this treatment, that is, by heating the porous ceramic substrate in an alkaline solution, Si—Al—
Crystals of zeolite composed of O are formed. After the treatment, excess sodium hydroxide remaining was washed and removed with water, and the reaction product was dried. The reaction product (Zeolitized Porous Ceramics: ZPC) obtained by using the porous ceramic substrate as a precursor is the zeolite porous body of the present example. 2.2 Structure of ZPC (X-ray Diffraction Measurement and Scanning Electron Microscope Observation) As a result of performing X-ray diffraction measurement on the generated reactant,
The X-ray diffraction pattern revealed several new diffraction peaks not found in the untreated material. From the d value and intensity of the newly formed peak, it was confirmed that zeolite (hydroxysodalite) was generated in the treated product.

From observation by a scanning electron microscope,
It was found that this zeolite was precipitated as fine crystals on the surface of the porous ceramic substrate and the surface of the internal pores. Moreover, it was found that many internal pores originally contained in the porous ceramic substrate were preserved as they were even after the formation of the zeolite layer by this treatment. 2.3 Effect of ZPC The ZPC of the present embodiment has a small resistance to transfer of a reactant due to its large continuous holes as a functional substance carrier such as a self-catalyst or a catalyst. When used as particles, the inside of the particles also functions effectively. Therefore, the efficiency per unit filling volume is large, and therefore, there are various applications in the fields of the chemical industry and the exhaust gas treatment device.

The ZPC of the present embodiment is suitable as a carrier for microorganisms and enzymes such as a bioreactor used in the food industry or in the biochemical treatment of wastewater. Furthermore, it can be used as a carrier for agricultural chemicals and fertilizers, or as a flooring material for horticulture. In addition, products with large communication holes have various uses as porous bodies for high-speed absorbing liquids.

Further, the ZPC carrier of this embodiment has a structure in which a zeolite layer is provided on its surface and internal pores as shown in FIG. 2, for example.
The ability to attach and grow microorganisms is even better.
That is, zeolite can quickly attach negatively charged microorganisms to the inner and outer surfaces of ZPC due to its cation exchange property as described above. Also, adsorption and removal of excess ammonia around the microorganism is promoted by cation exchangeability. In addition to the above-described structure of the internal pores, the action of such a zeolite brings the carrier into a state suitable for the propagation of microorganisms and promotes the growth. (2) Example 2 (Manufacture of ZPC by Autoclave) Next, Example 2 will be described.

In this embodiment, ZPC is manufactured by an autoclave. 1. Porous Ceramics Substrate The structure and manufacturing method of the porous ceramics substrate serving as the precursor of the ZPC of the present example are the same as those in Example 1, and the description thereof will be omitted. 2. 2. Zeolitized Porous Ceramics (ZPC: Using Autoclave) 2.1 Method for Zeoliteizing Porous Ceramics Substrate (Using Autoclave) The beaded porous ceramics substrate as in Example 1 was filled in a beaker with a volume of 50 ml. An aqueous solution of sodium hydroxide (concentration: 3.5 normal) enough to sufficiently use the porous ceramic substrate is introduced. Then, this beaker is charged into an autoclave and heated at 120 ° C. for 12 hours.

After heating and drying, ZPC of this example was obtained. 2.2 Structure and Properties of ZPC 2.2.1 Porosity and Strength of ZPC The porosity and compressive breaking strength of the ZPC of this example were measured in the same manner as in Example 1. In addition, as a comparative example, the structure and characteristics of an untreated carrier (that is, a porous ceramic substrate) were measured. The results are shown in Table 4 below.

[0064]

[Table 4]

Compressive breaking strength [MPa] = Compressive breaking load due to flat plate [N] / projected area of particles [m ² ] As is clear from Table 4, in the present embodiment, the porous ceramics were obtained after the zeolite treatment. 20μ formed on the substrate
Most of the large holes (cave holes) of m or more are maintained, and the surface aperture ratio and the internal Dalian communication holes are also maintained.
Although the compressive strength is lowered by hydrothermal treatment, it is 6 [M
Pa]. 2.2.2 Structure of ZPC (X-ray diffraction measurement and scanning electron microscope observation) In the same manner as in Example 1, the ZPC of this example was observed by X-ray diffraction and scanning electron microscope.

When the crystal structure of the ZPC of this example was examined by X-ray diffraction, it was found that, in addition to the diffraction line peaks of the porous ceramic substrate, those which were considered to be hydroxysodalite (crystal plane spacing d = 6.31 angstroms) , 3.6
Several new peaks containing 5 angstrom) appeared. FIGS. 5 and 6 show the structure of the ZPC of this example examined using a scanning electron microscope. As shown in FIGS. 5 and 6, a large-diameter hole existing inside the porous ceramic substrate, and a small-diameter hole communicating with the dens are formed. Communication holes, irregular pores with many internal holes consisting of small diameter communication holes communicating the cave holes and the outside, on the original hole surface of the irregular substrate, a columnar shape of several μm to 40 μm and a spherical shape which seems to have grown, or It was confirmed that a new crystal having a shape of a large number of folds was formed.

FIG. 5 is a scanning electron microscope photograph of the surface of the ZPC, and FIG. 6 is a scanning electron microscope photograph of the fractured surface of the ZPC. 2.3 Function confirmation test of ZPC (cation exchange capacity measurement) In order to confirm the function of ZPC of this embodiment, Z
PC (ie, a carrier provided with a zeolite layer on the surface of a porous ceramic substrate by an autoclave treatment)
And the carrier of the comparative example (that is, the porous ceramic substrate), the cation exchange capacity (CEC) was measured.
The carrier of Example 1 (ZP by treatment under atmospheric pressure)
About C), it measured similarly. The measurement results are shown in Table 5 below.

[0068]

[Table 5]

As is clear from the measurement results, in the case of the ZPC carrier of the present example, the cation exchange capacity was 1.1 [me / 100 g] of the untreated carrier (substrate). It was 9.4 [me / 100 g]. In other words, the cation exchange capacity of the ZPC carrier of this example is higher than that of the comparative example. The apparently small absolute value of the cation exchange capacity means that the weight at the time of calculating the amount of cation exchange is included not only in the zeolite layer but also in the porous ceramic substrate (not zeolite) serving as the skeleton thereof. The value has an effect.

The cation exchange capacity of the carrier of Example 1 was larger than that of the untreated carrier (substrate), and was 3.3 [me].
/ 100 g]. 2.4 Effects of the present embodiment As described above, since the zeolite layer is formed in the autoclave in the present embodiment, it is possible to easily and mass-produce the ZPC having the characteristics obtained in the first embodiment. Can be.

The ZPC thus manufactured is
Has a unique internal pore and a zeolite layer on the inner and outer surfaces (that is, the outer surface of the carrier and the surface of the inner pore) as in Example 1, so that zeolite adsorbability, ion exchange property, The performance such as catalytic property and molecular sieve can be further exhibited. (3) Example 3 (Treatment by Autoclave: Operation during Alkaline Solution Concentration) Next, Example 3 will be described.

In this embodiment, the ZPC is manufactured in an autoclave by controlling the concentration of the alkaline solution during the treatment. 1. Porous Ceramics Substrate The structure and manufacturing method of the porous ceramics substrate serving as the precursor of the ZPC of the present example are the same as those in Example 1, and the description thereof will be omitted. 2. 2. Zeolitized Porous Ceramics (ZPC: Manipulating Alkaline Concentration) 2.1 Method for Making Porous Ceramics Base into Zeolite (Manipulating Alkaline Concentration) ZPC Having Zeolite Layer Prepared in Example 2
Was charged into an Erlenmeyer flask, and further diluted with an aqueous sodium hydroxide solution (concentration: 2 N) as in Example 2.
Add 50 cc.

This was again put in an autoclave at 120 ° C.
For 70 hours. The ZPC was dried after heating, to obtain a ZPC of this example. 2.2 Structure and Properties of ZPC 2.2.1 Porosity and Strength of ZPC The porosity and compressive breaking strength of the ZPC of this example were measured in the same manner as in Example 1. The results are shown in Table 6 below.
It writes in. For comparison, the measurement results of the carrier of Example 2 are also shown.

[0074]

[Table 6]

Compressive breaking strength [MPa] = Compressive breaking load by plate [N] / projected area of particles [m ² ] As is clear from Table 6, the ZPC carrier of Example 3
Although the porosity decreases with the formation of the zeolite, the pores of 1 μm or more are maintained, and the movement of the molecular fluid is sufficiently easy. Although the ratio of the surface openings and the internal communication holes is also reduced, the characteristics of the porous ceramic substrate before the treatment remain. In addition, the compressive strength is slightly increased by the re-hydrothermal treatment, and exceeds 7 [MPa]. 2.2.3 Structure of ZPC (X-ray Diffraction Measurement) The X-ray diffraction of the ZPC of this example was measured in the same manner as in Examples 1 and 2.

As a result, in addition to the diffraction line peak of Example 2, a peak considered to be a philipsite (d = 7.1)
(0 angstrom, 5.02 angstrom, 4.09 angstrom) and many unidentifiable peaks were also confirmed, confirming that a zeolite layer different from that of Example 2 was formed.

In Example 3, a template agent (eg, tetrapropylammonium bromide) was
The ZPC is manufactured by adding to an aqueous alkali solution.
When X-ray diffraction was measured, an unidentifiable diffraction line peak different from that of Example 3 was confirmed. 2.3 Function confirmation test of ZPC (cation exchange capacity measurement) In order to confirm the function of the carrier of the ZPC of the present example, the ZPC of the present example (that is, one subjected to an alkali solution concentration operation)
And the cation exchange capacity (CEC) was measured using the ZPC of Comparative Example (ZPC of Example 2). The measurement results are shown in Table 7 below.

[0078]

[Table 7]

As is clear from Table 7, by changing the concentration of the alkaline solution used for the hydrothermal treatment during the processing, it is possible to produce another zeolite having a higher cation exchange capacity. 2.4 Effects of the present embodiment In the present embodiment, by performing the hydrothermal treatment by controlling the alkali solution concentration as described above, the ZPC having higher performance can be obtained.
There is an advantage that can be obtained.

The embodiments of the present invention have been described above.
The present invention is not limited to such embodiments at all, and it goes without saying that the present invention can be carried out in various modes without departing from the gist of the present invention. In Example 3 and Examples 1 and 2 described above, it is possible to promote the selective formation of a specific type of zeolite nucleus by adding a known template agent (for example, tetrapropylammonium bromide) to an alkaline solution. It is.

[0081]

As described in detail above, the zeolite-containing porous body of the invention according to claims 1 to 5 can be provided with the necessary conditions (1) to (1) to (1) to (4), for example, using the carrier described in the section of [Background Art]. 3)
Is satisfied, so that there is an advantage that there is no problem in waste disposal and the mechanical strength is excellent.

In addition, since the porous ceramic substrate in the zeolite-formed porous body has a zeolite layer formed on the surface thereof and the surface of the internal pores, the zeolite has adsorptive properties, ion exchange properties, catalytic properties, molecular sieve properties and the like. The performance can be further exhibited. In particular, when used as a carrier for growing microorganisms, it has excellent germ-growing ability due to cation exchange. It also has sufficient strength against transport, charging and discharging into the reactor tank, operation to prevent channeling in the reactor, deterioration due to long-term use, etc. It is suitable as a carrier for microorganisms, enzymes, or germicides such as bioreactors used for chemical treatment.

Further, according to the method for producing a porous zeolite according to the invention of claims 6 to 13, the porous zeolite having the above-mentioned excellent properties can be easily produced.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a cross section of a carrier.

FIG. 2 is an enlarged schematic view showing a portion A in FIG. 1;

FIG. 3 is a photograph taken by a scanning electron microscope showing the surface of a porous ceramic substrate of the carrier (particles) of Example 1.

FIG. 4 is a photograph taken by a scanning electron microscope showing a fracture surface of a porous ceramic substrate of the carrier (particles) of Example 1.

FIG. 5 is a photograph taken by a scanning electron microscope showing the surface of a carrier (particles) of Example 3.

FIG. 6 is a scanning electron microscope photograph showing a fracture surface of a carrier (particle) of Example 3.

Continued on the front page (51) Int.Cl. ⁶ Identification code FI C02F 3/10 C02F 3/10 A C04B 41/85 C04B 41/85 D (72) Inventor Akio Hemi 645-20 Kuruzumicho, Matsuyama-shi, Ehime

Claims (13)

[Claims] 1. A porous ceramic substrate subjected to a zeolite treatment comprises: a large-diameter cavity formed therein; a small-diameter communication hole communicating between the dens; and the cavity and the outside. A large number of internal holes having a communication hole having a small diameter communicating therewith are provided, and the following condition (i) consisting of (i) to (v) is satisfied, and (a) (i) communication having a hole diameter of 1 to 360 [μm] The median equivalent hole diameter of the cumulative pore volume is 40 ± 25 [μm]; (ii) The median equivalent circular diameter of the accumulated cave area of the pore diameter of 5 to 1100 [μm] is 320 ± 150 [μm]. μm], (iii) the internal hole formed by the cave hole and the communication hole has an irregular shape whose inside diameter and its internal shape are irregularly changed, and (iv) a hole diameter of 1 Of the porosity of the internal pore composed of up to 360 [μm], composed of a pore diameter of 20 [μm] or more (V) the compressive fracture strength is 5 [MPa] or more, and the surface of the porous ceramic substrate and the surface of the internal hole satisfying the above conditions are: A zeolite-formed porous body having a porous zeolite layer. 2. The zeolite-made porous body according to claim 1, wherein the zeolite-made porous body has a compressive breaking strength of 5 [MP].
a) The zeolite-formed porous body characterized by the above. 3. The zeolite-containing porous body according to claim 1 or 2, further comprising an outer layer portion having an effective use depth according to a use purpose on a surface side of the zeolite-use porous body, A zeolite-made porous body comprising: an inner layer portion provided inside the outer layer portion; the outer layer portion having the irregularly shaped porosity; and the inner layer portion that is not effectively used having no porosity. 4. The zeolitic porous body according to claim 1, wherein the zeolitic porous body is used as a carrier. body. 5. The zeolitic porous body according to claim 4, wherein the zeolitic porous body is a carrier for growing microorganisms. 6. The method for producing a porous zeolite body according to any one of claims 1 to 7, wherein when producing a porous ceramic substrate having the configuration of (a), the porous ceramic body has a thickness of 20 μm or more. After the powder of the ceramic material containing 20% by weight or more of the large particle diameter raw material of
When firing at 〜1450 ° C., in a firing temperature range of 1000 ° C. or less, eutectic is partially started in a structure having no pores of 5 μm or more with an increase in firing temperature and elapsed time, and between the coagulated nuclei and the nuclei. A method for producing a zeolite-formed porous body, characterized by using a method for producing a eutectic agglomeration nucleus crosslinked porous ceramics in which both of the crosslinked portions increase in quantity from small pores to large pore structure. 7. The method for producing a zeolite-made porous body according to claim 6, wherein the mixed raw material powder (A) used in the production of the porous ceramic substrate having the configuration of (A) is used. , Plant components, synthetic resin powder, coal, coke powder, salts, and other removal components (B) to be removed in a post-process are mixed at a ratio of (A) / (B) = 20 to 1, and the above-mentioned after firing is mixed. A zeolite characterized by increasing the porosity of a predetermined pore size by the particle size of the removed substance (B) and at the same time increasing the total porosity by the residual pores caused by the removed substance (B). The method for producing a porous body. 8. The method for producing a zeolite-made porous body according to claim 6 or 7, wherein the porous ceramic substrate having the configuration (a) is
A method for producing a porous zeolite body, comprising forming a zeolite layer on the surface of the porous ceramic substrate by heating in an alkaline solution. 9. A porous ceramic substrate mainly composed of silica and alumina, a large-diameter hole formed therein, a small-diameter communication hole communicating between the holes, and a communication between the hole and the outside. A porous ceramic substrate having a plurality of internal holes having a communication hole having a small diameter and satisfying the following condition (i) consisting of (i) to (iii): The internal hole composed of the communication hole is an irregular shape in which the inner diameter and the internal shape are changed irregularly; (ii) pores of the internal hole having a hole diameter of 1 to 360 [μm] The porosity having a pore size of 20 [μm] or more is 20 [%] or more, (iii) the compressive fracture strength is 5 [MPa] or more. By heating in an alkaline solution Forming a porous zeolite layer made of zeolite on the outer surface and inner pore surface of the porous ceramic substrate. 10. The method for producing a zeolite-formed porous body according to claim 8 or 9, wherein a template agent for selectively generating zeolite is added to the alkaline solution. A method for producing a zeolite porous body. 11. The method for producing a porous zeolite according to any one of claims 8 to 11, wherein the concentration of the alkaline solution is changed during a processing step. Production method of the body. 12. The method of producing a porous zeolite according to claim 8, wherein the heating is performed in the atmosphere. Method. 13. The method for producing a porous zeolite according to any one of claims 8 to 12, wherein the heating is performed in an autoclave in a pressurized state. Production method of the body.