JP2007070161A - Porous composite body, and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a porous material composed of an accumulated body of porous bodies each having an inorganic porous structure of a metallic compound(s) and holding the outer shell shape of a granular biological material, to provide a method for producing the same, and to provide a functional member. <P>SOLUTION: The porous material is formed in such a manner that a metallic compound(s) is precipitated, covered or mixed on the surface of a granular biological material or into a solution. The porous material is composed of an accumulated body of porous bodies each having a porous membrane structure of the metallic compound(s) and holding the outer shell shape of the biological material. The production method uses the same. The functional member is obtained by using the same. According to this invention, the porous material having bimodal pores of macropores whose pore shape and pore size are relatively uniformly arranged and mesopores composed as a wall can be easily produced and provided by an environment-friendly means. The porous material can be suitably used as porous materials such as an absorber, a separation material, a catalyst and a filter utilizing the characteristics of its high adsorption performance. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a porous composite and a method for producing the same, and more specifically, using a particulate biological material as a template, depositing, coating or mixing a metal compound on the surface of the solution in a slurry to form a slurry, Accumulation of the composite with the porous body having a porous wall structure of the particulate biological material and the metal compound formed by molding and maintaining the outer shape of the biological material, or the porous body The present invention relates to a porous material comprising a body, a production method thereof, and a use as a functional member. The present invention provides a porous material having a porous wall structure in which the shape and particle size are substantially uniform and the outer shell shape of the particulate biological material is maintained by using a particulate biological material such as yeast particles as a template. In addition, it is produced and provided in a simple and environmentally friendly manner, and further, the present invention is based on the porous structure of the porous material described above, such as weight reduction, release of substances contained inside, heat insulation, etc. We provide new technologies and new products related to new highly functional porous inorganic materials and functional members that exhibit their properties.

Ceramic porous materials are excellent in heat resistance, chemical resistance, light weight, etc., and are therefore used in a wide range of fields such as filters, catalysts, separation membranes and adsorbing materials. Such a porous material is required to have a pore size suitable for each application. For example, a membrane for a filter medium that needs to consider air permeability and fluid flow has various pore diameters in the range of 0.005 μm to 10 μm (see Non-Patent Document 1), optical materials, In particular, a photonic crystal or the like having a periodic refractive index change equivalent to the wavelength of light has a structure in which holes having a uniform size of 0.12 μm to 1 μm are regularly arranged in three dimensions. (Refer nonpatent literature 2). Further, when gas is adsorbed and separated by a gas sensor or a separation membrane, the function is exhibited by the presence of nano-order or angstrom pores (see Non-Patent Document 3).
Recently, higher porosity and improved adsorption properties are desired, and it is necessary to control the nano to macro structure of the material. Bimodal porous materials that combine the order of each pore attract attention. (See Non-Patent Document 4).

  As a method for producing a material having macropores, a polymer such as polystyrene or silica particles is used as a template, and after mixing the template and matrix raw material, the template is burned, dissolved, etc. to disappear and the pores are removed. There is a method of forming (see Non-Patent Document 5). In addition, research on materials in which holes are arranged by self-organizing a template two-dimensionally or three-dimensionally (see Non-Patent Document 6).

  However, according to the above-described method, the affinity between the resin particles and the matrix material is important, and the resin particles are poorly dispersible in water. It has been pointed out that surface modification such as introduction of silanol groups into the particles is necessary (see Non-Patent Document 7). In addition, since the resin particles that can serve as a template are made of a petroleum-based resin, consideration for the environment is required for firing.

  On the other hand, recently, as a prior art, as a biotemplate, a technique for copying DNA structure onto silica gel and semi-permanently storing DNA genetic information (see Non-Patent Document 2) and bacteria (see Non-Patent Document 3) In addition, there have been reported cases in which nanostructures are produced using chromosomes (see Non-Patent Document 4) or the like as templates.

On the other hand, the present inventors have focused on using yeast as a biotemplate. Yeast has a cell wall mainly composed of saccharides such as β-glucan and α-mannan (see Non-Patent Document 5), is robust compared to other microorganisms such as E. coli, and is easy to handle as a template. Conceivable. As prior art, for example, as an example using the cell wall component of yeast particles and the structure thereof, a film biodegradable sheet (see Patent Document 1) and a film coating agent such as a tablet (see Patent Document 2) are produced. As other examples, removal by mercury adsorption for the purpose of environmental purification (see Patent Document 3), removal by adsorption of basic dye (see Patent Document 4), and the like have been attempted. However, these do not combine yeast with any effect, and are not examples of producing materials using yeast as a template.

  Furthermore, as a prior art, for example, as a case where a biological substance mainly composed of yeast and an inorganic material such as a metal oxide are combined, a metal catalyst having a metal oxide or a metal supported on the surface of a yeast cell in tobacco leaves. Composition for smoking (see Patent Document 5), and for controlling the growth of microorganisms provided with a hydrophilic synthetic resin layer containing a metal oxide, a metal hydroxide, and a metal salt on the surface of a thermoplastic synthetic resin nonwoven fabric Materials (see Patent Document 6) have been proposed. However, in the former, the amount of metal supported is 12.5% and the thickness is 31 μm with respect to the bread yeast diameter of 5 μm. It is considered to be inferior. In the latter case, since the metal compound is blended with a hydrophilic synthetic resin such as polyvinyl alcohol, it is considered that the metal compound is not actively brought into contact with the yeast particles.

JP 2002-97301 A JP 2002-249714 A JP-A-50-051988 JP 49-021950 A Japanese Patent Laid-Open No. 51-54996 JP 2000-45166 A

Katsutoshi Ando et al., “Porous materials-Characterization, production and Application-”, Fuji Techno System, pp. 800 (1999) Wijnhoven, J. E. G. J. and Vos, W. L., Science, Vol.281, pp. 802-804 (1998) Lin, C. L., Flowers, D.L. and Liu, P. K. T., J. Membrane Sci., Vol. 92, pp. 45-58 (1994) Kim, Y., Kim, C. andYi, J., Materials Research Bulletin, Vol. 39, pp. 2103-2112 (2004) Shi, X., Briseno, A.L., Sanedrin, R. J. and Zhou, F., Macromolecules, Vol. 36, pp. 4093-4098 (2003) Choi, D. G., Kim, S., Lee, E. and Yang, S. M., J. Am. Chem. Soc., Vol. 127, pp. 1636 -1637 (2005) Ding, X. , K. Yu, Y. Jiang, H. Bala, H. Zhang and Z. Wang: “A Novel Approach to the Synthesis of Hollow Silica Nanoparticles”, Materials Letters, 58, 3618-3621 (2004) Numata, M. , K. Sugiyasu, T. Hasegawa and S. Shinkai: “Sol-GelReaction Using DNA as a Template: An Attempt Toward Transcription of DNA into Inorganic Materials”, Angew. Chem. Int. Ed. , 43, 3279-3283 (2004) Davis, S. A. , S. L. Burkett, N. H. Mendelson and S. Mann: “BacterialTemplating of Ordered Macrostructures in Silica and Silica-SurfactantMesophases”, Nature, 385, 420-423 (1997) Sugiyasu, K. , S. Tamaru, M. Takeuchi, D. Berthier, I. Huc, R. Odaand S. Shinkai: “Double Helical Silica Fibrils by Sol-Gel Transcription of Chiral Aggregates of Gemini Surfactants”, Chem. Commun, 1212-1213 (2002) Hiroshi Aida et al .: “New edition of applied microbiology I”, p. 85, Asakura Shoten (1981)

  In such a situation, in view of the above prior art, the present inventors have conducted intensive research with the goal of developing a new porous material using a biotemplate. As one of the technologies, we focused on the production of porous materials using yeast. Yeast has been used industrially on a large scale, such as being used in the fermentation process in bread making for a long time, is easily available, and is inexpensive, with a size of only a few microns for use as a macropore. Appropriate. Yeast can be considered as a microcapsule that contains 70% of water in a living state and contains water necessary for hydrolysis such as alkoxide, and is more robust than other microorganisms such as Escherichia coli. It is easy to handle as a template. Furthermore, the surface is hydrophilic and does not require additional hydrophilic treatment like polystyrene latex.

  The present inventors use a particulate biological material such as yeast particles as a template, deposit a metal compound on the surface of the solution in a solution, coat or mix it into a slurry, and fire the molded body formed by molding. Succeeded in producing a porous material composed of an aggregate of porous bodies having a porous wall structure of the metal compound and retaining the outer shape of the biological material, and completed the present invention. . That is, the present invention is a composite having a structure in which yeast particles and the like are uniformly dispersed in the metal compound prepared by adding a metal compound to yeast particles and depositing, coating or mixing the metal compound on the surface of the yeast particles and the like. It is an object of the present invention to provide a porous material comprising a body, a porous material obtained by baking the complex to remove yeast particles, and a method for producing the same.

  Another object of the present invention is to provide a bimodal porous material having macropores and mesopores having relatively uniform particle shapes and particle diameters. Another object of the present invention is to provide a method for producing a porous material that makes it possible to produce a porous material having a larger specific surface area by making the atmosphere to be heat-treated inert or reducing. It is what. In addition, the present invention relates to a porous material whose surface is controlled in terms of its chemical properties, pore structure, crystal structure, etc., according to its synthesis conditions, types, drying / firing conditions, etc. It is intended to provide a method.

  Another object of the present invention is to produce and provide a composite having a biological material having biocompatibility inside by leaving the biological material in a composite comprising a particulate biological material and a metal compound. It is what. Furthermore, an object of the present invention is to provide a porous material for use in, for example, a filter, an environmental purification material, a heat insulating material, and a catalyst.

The present invention for solving the above-described problems comprises the following technical means.
(1) A composite porous material formed by compositing a metal compound with a particulate biological material, and having a porous wall structure of the particulate biological material and the metal compound; A porous material comprising a composite with a porous body having a shell shape or an aggregate of the porous body.
(2) The porous material according to (1), wherein the particulate biological material is yeast, starch, chlorella (algae), lactic acid bacteria, spores, or pollen.
(3) The porous material according to (1), wherein the metal compound is a metal, a metal oxide, a metal hydroxide, a metal nitride, or a composite thereof.
(4) The porous material according to (3), wherein the metal component of the metal compound is titanium, zirconium, aluminum, zinc, yttrium, hafnium, tin, antimony, or silicon.
(5) The porous material according to (1), which is a porous material not containing particulate biological material.
(6) Using a particulate biological material as a template, depositing, coating or mixing a metal compound on the surface of the biological material, and having a porous structure of the particulate biological material and the metal compound, A composite with a porous body that retains the outer shell shape is prepared, and then, optionally, a porous material containing the particulate biological material or the particulate biological material is contained by heat treatment. A method for producing a porous material, comprising producing a non-porous material.
(7) The method for producing a porous material according to (6), wherein the particulate biological material is yeast, starch, chlorella (algae), lactic acid bacteria, spores, or pollen.
(8) The method for producing a porous material according to (6), wherein the metal compound is a metal, a metal oxide, a metal hydroxide, a metal nitride, or a composite thereof.
(9) The method for producing a porous material according to (8), wherein the metal component of the metal compound is titanium, zirconium, aluminum, zinc, yttrium, hafnium, tin, antimony, or silicon.
(10) A functional member having high adsorption performance, characterized in that the porous material according to any one of (1) to (5) is a constituent element.
(11) The functional member according to (10), wherein the member is a filter, an environmental purification material, a heat insulating material, a catalyst, or an optical material.

Next, the present invention will be described in more detail.
The present invention is a composite formed by depositing, coating or mixing a metal compound on the surface of a particulate biological material, having a porous membrane structure of the metal compound, and maintaining the outer shell shape of the biological material The porous biological material is composed of an aggregate of porous materials, and the particulate biological material is used as a template to deposit, coat or mix the metallic compound on the surface of the biological material, and the particulate biological material and the metal By producing a composite with a porous body having a porous structure of the compound and retaining the shape of the outer shell of the biological material, and then optionally subjecting it to a heat treatment, the particulate biological material Or a porous material that does not contain the above-described particulate biological material.

In the present invention, the particulate biological material used as a template is preferably a biological material having an average particle size of 0.2 to 40 μm, such as yeast, starch, chlorella (algae), lactic acid bacteria, spores, Pollen etc. are illustrated. As the yeast, any yeast may be used as long as it belongs to the taxonomics, for example, beer yeast, wine yeast, baker's yeast, torula yeast, etc., more specifically, Saccharomyces cerevisiae, Saccharomyces rouxii, and Saccharomyces Saccharomyces (Saccharomyces rouxii)
carlsbergensis), Candida utilis, Candida tropicalis, Candida lipolytica
lipolytica), Candida flaveri and the like. As yeast, it is preferable to use live yeast, but even when a yeast of a form other than live yeast, such as dry yeast, is used, for example, it can be suspended in water and treated in the same manner as live yeast.

  Moreover, in this invention, as a thing which exhibits the performance equivalent to or similar to yeast particles, for example, corn starch (average particle size 2 to 30 μm), wheat starch (average particle size 2 to 40 μm), rice starch is preferable. (Average particle size 2 to 5 μm), bean starch (average particle size 25 to 40 μm), potato starch (average particle size 2 to 80 μm), unicellular green algae, and spherical or ellipsoid with an average particle size of 2 to 12 μm Chlorella (algae), which is a fine particle of These particulate biological materials can be used alone or in combination of two or more as required. Although there is no restriction | limiting in particular in the shape and magnitude | size of the biological material to be used, As a shape, the thing of a shape close | similar to a spherical shape is preferable as possible, and the magnitude | size is preferably 0.2-40 micrometers, for example, 1-5 micrometers The thing of the range of is more preferable.

  In the present invention, the metal compound means a metal, a metal oxide, a metal hydroxide, a metal nitride, or a composite thereof, and there is no particular limitation on the crystallinity thereof. Any of these can be used. The metal compound to be coated is not particularly limited, but for example, one or more metal compounds selected from zinc, yttrium, aluminum, titanium, zirconium, hafnium, tin, antimony, and silicon are preferable. Specific examples of the hydroxide and oxide include zinc oxide, yttrium oxide, aluminum hydroxide, alumina, titania, zirconia, hafnium oxide, tin oxide, antimony oxide, and silica. Among these, an oxide is particularly preferable. A porous structure made of an oxide can be formed by, for example, a hydrolysis reaction, a thermal decomposition reaction, or the like of an inorganic metal salt, an organic metal salt, or a metal alkoxide. Moreover, these metal compounds can be used individually by 1 type or in combination of 2 or more types as needed.

  The amount of the metal compound used is not particularly limited, and can be appropriately selected according to various conditions such as the type and particle size of the biological material such as yeast particles, the type of the metal compound itself, the use of the porous material to be obtained, Usually, 5 to 200 parts by weight, preferably 10 to 100 parts by weight, are used with respect to 100 parts by weight of the yeast particles. When adding a metal compound or a solution or dispersion thereof to a biological material, the biological material such as yeast particles can be heated to about 15 to 95 ° C. or not heated.

  Next, the present invention will be described based on an example in which yeast particles are used as a template and an alkoxide is used as a metal compound, but other biological materials and metal compounds may be used in the same manner as described below. Needless to say, the porous material of the present invention can be produced, but the present invention is not limited to the following method.

  An example of the method for producing a porous material according to the present invention will be described. First, triethanolamine as a stabilizer is mixed with an alcohol solution of a metal alkoxide and stirred at room temperature. This solution is mixed with a dispersion in which yeast particles are dispersed in water, and stirred for a long time to precipitate alkoxide hydrolyzate on the surface of the yeast particles to obtain coated yeast particles. The hydrolyzate is also produced in the solution, producing a slurry of yeast particles and hydrolyzate sol. The mixed slurry is processed by a centrifugal separator, molded, dried, and then heat-treated at 500 to 1200 ° C., whereby the precipitated hydrolyzate is crystallized and the organic substance is decomposed to obtain a porous material. By the series of these steps, the porous material of the present invention is produced.

  In the present invention, as described above, the reactivity of the raw material is controlled in the solution in which the yeast particles are dispersed, and the raw material of the metal compound is added to precipitate the metal compound on the surface of the yeast particles. For example, for a raw material having a slow reaction rate such as tetraethoxysilane, a catalyst such as ammonia is added to the solution. Conversely, for a raw material such as titanium isopropoxide having a fast reaction rate, triethanolamine (TEA ) Is previously combined with titanium isopropoxide, mixed and precipitated.

  Thus, in the present invention, the stabilizer is used to control the reactivity of the reaction solution and participate in the formation of macropores. TEA has an ethanolamino group and easily exchanges alcohol with an alkoxide to produce an amino alcoholate, forming a chelate ring and stabilizing AIP. AIP stabilized with TEA is considered to behave differently from that of AIP alone in the process of producing aluminum hydroxide by hydrolysis and the process of densification by firing. Therefore, the effect of TEA-added molded body preparation was investigated by performing thermal analysis (see FIGS. 1 and 2) and SEM observation (see FIG. 3) showing the microstructure of the product.

A reaction was performed by adding TEA to AIP without adding yeast, followed by hydrolysis with water and that obtained by adding water to only AIP without addition of TEA for hydrolysis. According to DTA, the TEA-free sample shows an endothermic reaction at 280 ° C. This peak is considered to be a peak due to dehydration decomposition of aluminum hydroxide. The decrease of 35% in weight change from TG corresponds to a moisture content of 35% shown in 2Al (OH) ₃ → Al ₂ O ₃ + 3H ₂ O. In contrast, the TEA-added sample had only an exothermic reaction in the vicinity of this temperature in DTA.

  This is considered that the endothermic peak does not appear and only the exotherm appears because the combustion of the unreacted portion of AIP and the hydrolyzate is larger than the endothermic reaction due to the dehydration decomposition of aluminum hydroxide. In DTA, peaks are observed at 383 ° C. and 492 ° C. Since the ignition point of TEA is 324 ° C., it is considered that these are combustion of unreacted parts related to TEA. In the case of no addition, the weight change was completed at 300 ° C., but in the case of addition of TEA, the weight change continued to 500 ° C. This is considered to be because the generated hydroxide sol was stabilized by TEA and remained up to a high temperature.

  According to SEM observation, the one without TEA was not sufficiently retained after being molded and was in a fragile state. In contrast, the added material formed a dense wall with the sol. Therefore, when TEA is not added, macropores that should be formed by yeast burnout are hardly formed, whereas added ones form macropores of several μm and walls that separate them. It is possible. In addition, in the process of producing these molded articles, it is considered that the dispersion of yeast, the yeast arrangement, and the filling of the sol are related to the formation and baking of the aluminum hydroxide sol described above.

  Since yeast has a hydrophilic surface, it was highly dispersed when the solution was mechanically stirred. Regarding the production of aluminum hydroxide, it is considered that after adding the raw material to water, aluminum hydroxide is produced on the yeast surface and in the solution, and a mixture of yeast and aluminum hydroxide sol is present in the solution. Therefore, by performing a solid-liquid separation process by centrifugation, a cake can be formed by crushing the yeast without concentrating the yeast and the sol without separating the sol, and a porous body in which macropores are uniformly dispersed by baking. Can be produced. Since an excessively stable solution is not suitable for the hydrolysis reaction, the TEA / AIP ratio is suitably in the range of 0.1-1.

  The reaction rate of the metal compound can also be adjusted by changing the type of solution. As the solution, for example, water, alcohols, ethers, and mixtures thereof are used. It is known that when an alkoxide is used as a raw material, the reaction becomes slow when an alcohol exchange reaction such as ethanol occurs in the solution. Therefore, by using a hydrophobic organic solution such as ethanol and hexane as the solution, it becomes possible to deposit the metal compound uniformly on the surface of the yeast particles, and form pores that accurately capture the shape of the particulate biological particles. (See Japanese Patent Laid-Open No. 4-45835).

  In the present invention, yeast particles whose surfaces are coated with a metal compound or a slurry in which these particles are uniformly mixed are separated from the reaction mixture by a general method such as filtration and centrifugation, and a solid is formed, and then necessary. After drying according to the above, the inorganic porous material can be produced by firing and burning or pyrolyzing the yeast particles. FIG. 4 shows an SEM photograph of the dried yeast and aluminum hydrolyzate sol mixture dispersed in ethanol and dried. Although cracks due to drying were observed, the sol uniformly covered the surface of the yeast and between the yeasts in a dense film form. Moreover, the aggregation between yeasts or the non-uniform aggregation between sols was hardly seen.

  As shown in the thermal analysis results in FIG. 5 and FIG. 6, the baking temperature is such that when the yeast particles in the composite material containing the metal compound in which the yeast particles are uniformly dispersed as a matrix are burned away, The temperature is not particularly limited as long as it can be decomposed and burned, but in order to thermally decompose yeast particles almost completely and to suppress selection of crystal structure and grain growth of the inorganic substance, the firing temperature is usually 500 to 1200. ° C, particularly preferably 600 to 800 ° C. The firing time is usually 0.5 to 10 hours. In addition, in the case where the yeast particles are left and only the crystal structure of the metal compound is selected, the firing temperature is usually 200 to 800 ° C., particularly 300 to 500 ° C., and the firing time is usually 0.5 to 10 hours. is there.

  The crystallinity of the metal compound can be controlled by controlling the heat treatment conditions of the composite material using the metal compound in which the yeast particles are uniformly dispersed as a matrix. For example, when an aluminum hydrolyzate in which yeast particles are uniformly dispersed is heat-treated, 900 to 1100 ° C. is γ-alumina, and 1200 ° C. greatly changes the crystal system from γ to α. The crystallinity can be controlled by adjusting these temperatures (see FIG. 7). Further, by adding α-alumina having good crystallinity at the stage of the metal compound slurry in which the yeast particles are uniformly dispersed, α-alumina can be obtained at 1100 ° C., which is 100 ° C. lower than that without addition (see FIG. 9).

Further, in the heat treatment in an oxidizing atmosphere, the macropores gradually contracted as the heat treatment temperature increased to 500 ° C. and further to 1000 ° C., and the yeast particles had a diameter of 2 to 4 μm before the heat treatment. After the heat treatment, it becomes 1 to 2 μm (see FIG. 2). Furthermore, as shown in the TEM photograph (see FIG. 10), the wall of the porous material is composed of nanoparticles, and mesopores are formed by the gaps between the particles and the pores in the particles. As shown in FIGS. 11 and 12, the mesopores can be changed from 6 nm to 11 nm in pore diameter by increasing the heat treatment temperature. The specific surface area, as shown in FIG. 13, changes from ^38m 2 / g to 205m ² / g.

The atmosphere at the time of firing is not particularly limited. For example, an oxidizing atmosphere such as air, a reducing atmosphere such as hydrogen gas, carbon monoxide gas and ammonia gas, an inert atmosphere such as nitrogen gas, helium gas and argon gas, etc. Can be mentioned. When calcination is performed in an oxidizing atmosphere, the yeast particles are burned out and an inorganic porous material is obtained. When calcination is performed in a reducing atmosphere or an inert atmosphere, a complex of yeast particles and a metal compound is obtained. The specific surface area and pore distribution were a composite of alumina and yeast, and the sample heated at 1000 ° C. for 3 hours at a heating rate of 10 ° C. per minute was 119 m ² / g. When the heat treatment was performed in a nitrogen atmosphere with respect to 9 nm, the peak of the pores was 4 nm at 142 m ² / g, and the distribution was sharper than in the atmosphere (see FIGS. 14, 15, and 16).

  In the present invention, the wall thickness of the porous material can be controlled. When a molded body is produced by centrifuging a mixture of yeast and aluminum compound sol dispersed in water, separation of yeast and aluminum hydrolyzate is not observed, and a uniform bulk body is obtained. Therefore, the ratio of the volume of macropores burnt down by yeast and the volume of alumina as a matrix can be changed by the ratio of the volume of yeast initially charged and the aluminum raw material to be added. Furthermore, by changing these ratios, the wall thickness of the matrix can also be changed. FIG. 17 shows SEM photographs of samples obtained by mixing yeast and aluminum compound raw materials at various ratios and heat-treated at 700 ° C. for 3 hours.

  In FIG. 17 (a), the thickness of the wall is submicron everywhere, and in the thin portion, a hole combined with the adjacent macro hole can be seen. At the back of the screen, macropores that are thought to be contacts of yeast are also formed, and the entire bulk body is predicted to have a three-dimensionally continuous honeycomb structure. Furthermore, as the ratio is increased, as can be seen from FIGS. 17B and 17C, the wall thickness is submicron, but the number of walls per unit area decreases. It is observed that the wall thickness is increased on average. Thus, the film thickness can be controlled by changing the ratio of the yeast and the aluminum raw material.

  The present invention, when producing a porous material, by adjusting the reactivity by selecting raw material compounds, stabilizers, solvents, etc., formation of a uniform macropore structure that could not be achieved conventionally, The wall thickness of the porous material can be controlled, and the crystallinity of the porous material and the mesopores due to the fine structure of the wall can be controlled by adjusting the firing temperature and firing atmosphere. . In addition, the bimodal porous material having macropores and mesopores whose properties are arbitrarily controlled as described above can be used as a highly functional material useful in various technical fields.

  According to the present invention, (1) a porous inorganic material in which macropores are uniformly dispersed can be easily produced and provided. (2) The thickness of the wall of the porous material depending on the addition of raw materials, processing conditions, and firing atmosphere The wall surface structure, pore structure, and crystal structure can be controlled. (3) A complex with a metal compound having yeast particles etc. having affinity inside by leaving yeast particles etc. (4) The porous material can be used as, for example, a catalyst, a sensor, an environmental purification material, and a heat insulating material. (5) A complex that does not lose biological materials such as yeast particles. The effect that it can utilize suitably as a porous material which has the characteristic which biological material has, for example, the adsorption | suction ability of ion or gas, is show | played.

  EXAMPLES Next, although this invention is demonstrated concretely based on an Example, this invention is not limited at all by the following Examples.

  In this example, an alumina porous material was produced. As yeast, baker's yeast (Saccharomyces cerevisiae) was obtained as fresh yeast, and was used as a template after stirring and washing with distilled water several times. Aluminum isopropoxide (abbreviated as AIP) was used as a raw material for alumina. Triethanolamine (abbreviated as TEA) was used as a stabilizer for the alumina solution. The procedure for producing the porous material was as follows. First, 0.02 mol of AIP and TEA were mixed at a predetermined ratio and stirred at room temperature for 12 hours. Thereafter, 50 ml of water was added and stirring was continued. On the other hand, 5 g of yeast was added to 150 ml of water and dispersed. These two solutions were mixed and stirred for 60 hours to precipitate the alkoxide hydrolyzate on the yeast surface and in the solution, thereby obtaining a slurry in which the yeast and the aluminum hydrolyzate were uniformly mixed and dispersed. The slurry was processed with a centrifuge to produce a molded body, dried, and then fired to obtain an alumina porous material.

  In this example, a zirconia porous material was produced. As yeast, baker's yeast (Saccharomyces cerevisiae) was obtained as fresh yeast, and was used as a template after stirring and washing with distilled water several times. As a zirconia raw material, an 85% zirconium (IV) butoxide 1-butanol solution was used. Triethanolamine (abbreviated as TEA) was used as a stabilizer for the zirconium solution. The procedure for producing the porous material was as follows. First, 85% zirconium (IV) butoxide 1-butanol solution [zirconium (IV) butoxide (abbreviated as ZNB) 0.04 mol] and TEA were mixed at a predetermined ratio and stirred at room temperature for 12 hours. Thereafter, 50 ml of water was added and stirring was continued. On the other hand, 5 g of yeast was added to 150 ml of water and dispersed. These two solutions were mixed and stirred for 60 hours to precipitate the alkoxide hydrolyzate on the yeast surface and in the solution, thereby obtaining a slurry in which the yeast and zirconium hydrolyzate were uniformly mixed and dispersed. A molded body was prepared from the slurry by a centrifugal separator, dried, and then fired to obtain a zirconia porous material. FIG. 18 shows a scanning electron micrograph of the zirconia porous material produced in this example.

  In this example, a titania porous material was produced. As yeast, baker's yeast (Saccharomyces cerevisiae) was obtained as fresh yeast, and was used as a template after stirring and washing with distilled water several times. Titanium isopropoxide was used as a titania raw material. Triethanolamine was used as a stabilizer for the titanium isopropoxide solution. Titanium isopropoxide 0.04 mol and TEA were mixed at a predetermined ratio and stirred at room temperature for 12 hours. Thereafter, 50 ml of water was added and stirring was continued. On the other hand, 5 g of yeast was added to 150 ml of water and dispersed. These two solutions were mixed and stirred for 60 hours to precipitate the alkoxide hydrolyzate on the yeast surface and in the solution, thereby obtaining a slurry in which the yeast and the titanium hydrolyzate were uniformly mixed and dispersed. The slurry was processed by a centrifuge to produce a molded body and dried.

Furthermore, this was heat-treated at a predetermined temperature of 500 ° C. to 1000 ° C. to promote crystallization of titania and pyrolyze organic matter to make it porous. The porous material had submicrometer to several micrometer walls. FIG. 19 shows a scanning electron micrograph of the porous material produced in this example, and FIG. 20 shows each heat treatment condition of the titania porous material (before heat treatment, 500 ° C., 700 ° C., 900 ° C., 1000 ° C.). The X-ray diffraction pattern of is shown. Further, FIG. 21 shows a transmission electron micrograph of the wall of the titania porous material. The wall is composed of a few nanometers of anatase fine particles, the specific surface area is 112.1 m ² / g, and pores exist between the particles. FIG. 22 shows an adsorption isotherm of the titania porous material heat-treated at 500 ° C., and FIG. 23 shows the pore distribution of the pores. It can be seen that there are pores having a peak at 4 nm.

  In this example, a silicon product porous material was produced. As yeast, baker's yeast (Saccharomyces cerevisiae) was obtained as fresh yeast, and was used as a template after stirring and washing with distilled water several times. As a raw material for the silicon product, 5 ml of ethyl silicate was used. On the other hand, 3 g of yeast was dispersed in 4 g of water. By mixing these two solutions, and further adding 0.5 ml of ammonia as a reaction accelerator and stirring for 60 hours to precipitate the alkoxide hydrolyzate on the yeast surface and in the solution, yeast and silicon hydrolyzate Was obtained by uniformly mixing and dispersing. The slurry was treated with a centrifugal separator to form a molded body, dried, and then fired to obtain a porous material of a silicon product. In FIG. 24, the scanning electron micrograph of the porous material of the silicon product produced in the present Example is shown.

  In this example, a silicon product / titania porous material was produced. As yeast, baker's yeast (Saccharomyces cerevisiae) was obtained as fresh yeast, and was used as a template after stirring and washing with distilled water several times. As a raw material for the silicon product, 1 ml of ethyl silicate was used. Titanium isopropoxide was used as a titania raw material. Triethanolamine was used as a stabilizer for the titanium isopropoxide solution. 4.5 g of titanium isopropoxide and TEA were mixed at a predetermined ratio and stirred at room temperature for 12 hours. Thereafter, these two solutions were mixed.

  On the other hand, 3 g of yeast was dispersed in 4 g of water and 1 ml of ethanol. These two solutions were mixed and stirred for 60 hours to precipitate the alkoxide hydrolyzate on the yeast surface and in the solution, thereby obtaining a slurry in which the yeast and the silicon / titanium hydrolyzate were uniformly mixed and dispersed. The slurry was treated with a centrifuge to produce a molded body, dried, and then fired to obtain a porous material of silicon product / titania. FIG. 25 shows a scanning electron micrograph of the silicon product / titania porous material produced in this example.

  In this example, an alumina porous material was prepared by adding α-alumina seed particles. As yeast, baker's yeast (Saccharomyces cerevisiae) was obtained as fresh yeast, and was used as a template after stirring and washing with distilled water several times. Aluminum isopropoxide (abbreviated as AIP) was used as a raw material for alumina. For the purpose of promoting the transition to α-alumina, 0.02 g of α-alumina fine particles were added. Triethanolamine (abbreviated as TEA) was used as a stabilizer for the alumina solution. The procedure for producing the porous material was as follows. First, 0.02 mol of AIP and TEA were mixed at a predetermined ratio and stirred at room temperature for 12 hours. Thereafter, 50 ml of water was added and stirring was continued.

  On the other hand, 5 g of yeast was added to 150 ml of water and dispersed. These two solutions were mixed and stirred for 60 hours to precipitate the alkoxide hydrolyzate on the yeast surface and in the solution, thereby obtaining a slurry in which the yeast and the aluminum hydrolyzate were uniformly mixed and dispersed. The slurry was processed with a centrifugal separator to produce a molded body, dried, and then fired to obtain an alumina porous material. FIG. 26 shows a scanning electron micrograph of an alumina porous material prepared by adding α-alumina. FIG. 9 shows an X-ray diffraction diagram for each heat treatment condition (before heat treatment, 900 ° C., 1000 ° C.) of the alumina porous material prepared by adding α-alumina seed particles. By adding α alumina, α conversion was observed at 1100 ° C., which was 100 ° C. lower than that without addition.

  In this example, for the purpose of controlling the wall thickness of the porous material, by changing the ratio of the initially charged yeast volume and the aluminum raw material to be added, the volume of macropores that the yeast burned off and the alumina that is the matrix The volume ratio of the matrix was changed, and the wall thickness of the matrix was changed. FIG. 17 shows the ratio of aluminum isopropoxide to yeast AIP / Yeast (wt.%) (A) 20; (b) 40; (c ) 60 scanning electron micrographs are shown. In FIG. 17 (a), the wall thickness is submicron everywhere, and in the thin part, a hole that merges with the adjacent macro hole is also seen. At the back of the screen, macropores that are thought to be contacts of yeast are also formed, and the entire bulk body is predicted to have a three-dimensionally continuous honeycomb structure. Furthermore, as the ratio is increased, as can be seen from FIGS. 17B and 17C, the wall thickness is submicron, but the number of walls per unit area decreases. It was observed that the wall thickness increased on average.

In this example, the firing atmosphere was changed to the air and performed in a nitrogen atmosphere. An aluminum compound molded body in which yeast particles produced in the same manner as in Example 1 were uniformly dispersed was heat-treated at 1000 ° C. in nitrogen to produce an alumina porous material. FIG. 16 shows an SEM photograph of the fracture surface of this sample, FIG. 27 shows a TEM photograph of the wall, and FIGS. 14 and 15 show adsorption isotherms and pore distributions. In SEM observation, the appearance of the fracture surface is almost the same as that of 1.5 to 2 μm holes dispersed and observed as compared with heat treatment in the atmosphere. However, when comparing TEM photographs of the wall, a gap of several nanometers formed by the combination of partially crystallized several nanometer particles was seen in the atmosphere, and irregularities were formed on the surface. Particles could not be confirmed and had a smooth surface. Next, according to the adsorption isotherm, the pore volume decreased in the nitrogen atmosphere, but the specific surface area was 119 m ² / g in the air, but increased to 142 m ² / g in the nitrogen atmosphere. . Further, the peak of the pore distribution was 9 nm in the air, whereas it became a fine and sharp distribution of 4 nm in the nitrogen atmosphere.

  In this example, an alumina-based composite porous material having silver particles dispersed therein was produced. As yeast, baker's yeast (Saccharomyces cerevisiae) was obtained as fresh yeast, and was used as a template after stirring and washing with distilled water several times. Aluminum isopropoxide (abbreviated as AIP) was used as a raw material for alumina. Triethanolamine (abbreviated as TEA) was used as a stabilizer for the alumina solution. Silver chloride was used as a silver raw material. The procedure for producing the porous material was as follows. First, 0.02 mol of AIP and TEA were mixed at a predetermined ratio, 0.5 g of silver chloride was further added, and the mixture was stirred at room temperature for 12 hours. Thereafter, 50 ml of water was added and stirring was continued.

  On the other hand, 5 g of yeast was added to 150 ml of water and dispersed. These two solutions were mixed and stirred for 60 hours to precipitate the alkoxide hydrolyzate on the yeast surface and in the solution, thereby obtaining a slurry in which the yeast, aluminum hydrolyzate and silver compound were uniformly mixed and dispersed. The slurry was treated with a centrifuge to produce a molded body, dried, and then fired to obtain an alumina porous material in which silver particles were dispersed. FIG. 28 shows a scanning electron micrograph of the silver-dispersed alumina porous material produced in this example, and FIG. 29 shows its X-ray diffraction pattern.

  As described in detail above, the present invention is a composite formed by depositing, coating or mixing a metal compound on a particulate biological material, having a porous film structure of the metal compound, and According to the present invention, a porous material composed of an accumulation of porous bodies having an outer shell shape, a method for producing the same, and a functional member. It is possible to easily produce and provide a porous material having macro-modal pores and pores having relatively uniform pore sizes and mesopores formed on the wall by a gentle technique. Further, in the present invention, the complex in which the template made of biological material such as yeast particles has not disappeared is characterized by the characteristics of the biological material such as yeast particles, such as ion or gas adsorbing ability, and the like. It can be used as a new composite material with high functionality combining the characteristics of the shell structure. The porous material of the present invention has high functionality in the fields of, for example, adsorbents, ion exchange materials, separation materials, hazardous substance treatment materials, electrode materials, dielectric materials, catalysts, heat insulating materials, and environmental purification members. It can be suitably used as a porous material.

The thermogravimetric analysis result of the aluminum hydrolyzate (a) which has not added triethanolamine, and the aluminum hydrolyzate (b) which added triethanolamine is shown. The differential thermal analysis result of the aluminum hydrolyzate (a) which has not added triethanolamine, and the aluminum hydrolyzate (b) which added triethanolamine is shown. Product (a) produced from yeast particles and aluminum hydrolyzate without added triethanolamine, and porous material produced from yeast particles produced in Example 1 and aluminum hydrolyzate with added triethanolamine ( The scanning electron micrograph which heat-processed b) at 1000 degreeC is shown. The scanning electron micrograph before the heat processing of the alumina porous material produced in Example 1 is shown. The thermogravimetric analysis result of the yeast particle (a) and the mixture (b) of the yeast produced in Example 1 and the aluminum hydrolyzate sol is shown. The differential thermal analysis result of the mixture (b) of the yeast particle | grains (a) and the yeast produced in Example 1 and aluminum hydrolyzate sol is shown. The X-ray-diffraction pattern for every heat processing conditions (before heat processing, 900 degreeC, 1100 degreeC, 1200 degreeC) of the alumina porous material produced in Example 1 is shown. The scanning electron micrograph for every heat processing conditions (before heat processing, 900 degreeC, 1100 degreeC, 1200 degreeC) of the alumina porous material produced in Example 1 is shown. The X-ray-diffraction pattern for every heat processing conditions (before heat processing, 900 degreeC, 1100 degreeC) of the alumina porous material produced by adding (alpha) alumina seed particles in Example 6 is shown. The transmission electron micrograph of the wall of the alumina porous material produced in Example 1 is shown. The adsorption isotherm for every heat treatment condition (900 degreeC, 1000 degreeC, 1100 degreeC, 1200 degreeC) of the alumina porous material produced in Example 1 is shown. The pore distribution for every heat treatment condition (900 degreeC, 1000 degreeC, 1100 degreeC, 1200 degreeC) of the alumina porous material produced in Example 1 is shown. The specific surface area for every heat processing condition (900 degreeC, 1000 degreeC, 1100 degreeC, 1200 degreeC) of the alumina porous material produced in Example 1 is shown. The adsorption isotherm of the alumina porous material produced in Example 1 that was heat-treated at 1000 ° C. in a nitrogen atmosphere is shown. The pore distribution of what was heat-processed at 1000 degreeC in the nitrogen atmosphere of the alumina porous material produced in Example 1 is shown. The scanning electron micrograph of what heat-processed at 1000 degreeC in the nitrogen atmosphere of the alumina porous material produced in Example 1 is shown. The alumina porous material prepared in Example 7 was heat-treated at 700 ° C., but the ratio of aluminum isopropoxide to yeast AIP / Yeast (wt.%) Was (a) 20; (b) 40; (c) 60 scanning An electron micrograph is shown. The scanning electron micrograph of the zirconia porous material produced in Example 2 is shown. The scanning electron micrograph of the titania porous material produced in Example 3 is shown. The X-ray-diffraction pattern for every heat processing conditions (Before heat processing, 500 degreeC, 700 degreeC, 900 degreeC, 1000 degreeC) of the titania porous material produced in Example 3 is shown. The transmission electron micrograph of the wall of the titania porous material produced in Example 3 is shown. The adsorption isotherm of the titania porous material produced in Example 3 was heat treated at 500 ° C. The pore distribution of the titania porous material produced in Example 3 was heat treated at 500 ° C. The scanning electron micrograph of the porous material of the silicon product produced in Example 4 is shown. The scanning electron micrograph of the silicon product and the titania porous material produced in Example 5 is shown. The scanning electron micrograph of the alumina porous material produced by adding (alpha) alumina in Example 6 is shown. The transmission electron micrograph of the alumina porous material produced in Example 8 in nitrogen atmosphere is shown. The scanning electron micrograph of the silver particle dispersion | distribution alumina porous material produced in Example 9 is shown. The X-ray-diffraction pattern of 900 degreeC of the silver particle dispersion | distribution alumina porous material produced in Example 9 is shown.

Claims (11)

  A composite porous material formed by compositing a metal compound with a particulate biomaterial, having a porous wall structure of the particulate biomaterial and the metal compound, and having an outer shell shape of the particulate biomaterial A porous material comprising a composite with a retained porous body or an aggregate of the porous body.   The porous material according to claim 1, wherein the particulate biological material is yeast, starch, chlorella (algae), lactic acid bacteria, spores, or pollen.   The porous material according to claim 1, wherein the metal compound is a metal, a metal oxide, a metal hydroxide, a metal nitride, or a composite thereof.   The porous material according to claim 3, wherein the metal component of the metal compound is titanium, zirconium, aluminum, zinc, yttrium, hafnium, tin, antimony, or silicon.   The porous material according to claim 1, which is a porous material not containing particulate biological material.   Using a particulate biological material as a template, a metal compound is deposited, coated or mixed on the surface of the biological material, and has a porous structure of the particulate biological material and the metal compound, and has an outer shell shape of the biological material. The porous material containing the particulate biological material or the porous material not containing the particulate biological material is prepared by, optionally, heat-treating the composite with the porous body holding A method for producing a porous material, comprising producing a material.   The method for producing a porous material according to claim 6, wherein the particulate biological material is yeast, starch, chlorella (algae), lactic acid bacteria, spores, or pollen.   The method for producing a porous material according to claim 6, wherein the metal compound is a metal, a metal oxide, a metal hydroxide, a metal nitride, or a composite thereof.   The method for producing a porous material according to claim 8, wherein the metal component of the metal compound is titanium, zirconium, aluminum, zinc, yttrium, hafnium, tin, antimony, or silicon.   A functional member having high adsorption performance, comprising the porous material according to claim 1 as a constituent element.   The functional member according to claim 10, wherein the member is a filter, an environmental purification material, a heat insulating material, a catalyst, or an optical material.