JP7011119B2 - A monolith filter, a solid separation device using it, and a method for manufacturing the monolith filter. - Google Patents

Description

The present invention relates to a monolith filter, a solid separation device using the monolith filter, and a method for manufacturing the monolith filter.

A porous monolith having pores, which is composed of an inorganic material such as silica, is known. The monolith is widely used as a separation column for chromatography, an enzyme carrier, a catalyst carrier and the like. A sol-gel method, which is a liquid phase reaction, is generally used for producing such a porous monolith.
The sol-gel method uses a sol-gel reaction, that is, hydrolysis and polymerization (hypercondensation) of the compound, using an inorganic low molecular weight compound having a hydrolyzable functional group dispersed in a dispersion medium as a starting material. Typically, a method for obtaining an aggregate or a polymer of an oxide is shown.
The starting material, the inorganic low molecular weight compound, is, for example, a metal alkoxide typified by tetraalkoxysilane and a metal salt having a hydrolyzable functional group.

Patent Document 1 discloses a porous monolith having a through hole having a large pore diameter and a pore having a smaller pore diameter formed on the wall surface of the through hole, and the through hole and the skeleton exhibit a co-continuous structure. ing.
According to the porous monolith having such a hierarchical porous structure, for example, a separation column for chromatography having a small pressure loss while maintaining a high separation ability is realized, and it is desired for various uses as a porous monolith. The characteristics are realized. A porous monolith having a hierarchical porous structure can be obtained, for example, by proceeding with a sol-gel reaction in combination with a phase separation process.

Japanese Unexamined Patent Publication No. 6-265534

However, the above-mentioned porous monolith has micro-level pores and cannot be used as a nano-level filter.
An object of the present invention is to provide a nano-level monolith filter, a solid separation device using the same, and a method for manufacturing the monolith filter.

In order to solve the above problems, a monolith filter including a skeleton having mesopores and macropores existing between the skeletons, and at least one surface of the monolith filter is covered with the skeleton. Use.
A nano-level filter can be realized by utilizing the mesopores existing in the one-sided skeleton.

A step of preparing a solution containing a compound having a hydrolyzable functional group in a container, and a skeletal phase in which mesopores were formed by proceeding with hydrolysis, polymerization and phase separation of the solution by the sol-gel method. A step of forming a gel having a solution phase, and drying the formed gel to form a mesopore in the skeleton, the solution phase as a macropore, and a surface in contact with the container. Uses the process of forming a monolithic filter having the above-mentioned step of forming so as to be covered with a skeleton.

A skeleton can be formed on the surface in contact with the container to realize a nano-level monolith filter.

INDUSTRIAL APPLICABILITY According to the present invention, a nano-level filter and a method for producing the same can be provided.

(A) Internal cross-sectional view of the monolith filter 100 of the embodiment, (b) Cross-sectional view showing the surface of the monolith filter 100 of the embodiment. (A)-(b) Cross-sectional view illustrating the method for manufacturing the monolith filter of the embodiment, (c) Cross-sectional view of the monolith filter 100 of the embodiment put in the column 9. (A)-(b) Cross-sectional view illustrating how to use the monolith filter 100. (A)-(b) Cross-sectional view illustrating another method of using the monolith filter 100. Cross-sectional SEM diagram of the organic monolith of the example

<Structure>
FIG. 1A shows a cross-sectional view of the inside of the monolith filter 100. There is a skeleton 10 and a first opening 11. Further, there is a recessed portion 15 connected to the first opening 11. The skeleton 10 is distributed throughout the monolith filter 100.

FIG. 1B is a cross-sectional view including the surface of the monolith filter 100. The surface 21 is covered with the skeleton 10. Only the skeleton 10 is preferable for one surface of the surface 21, but in principle, it is necessary to cover the entire surface. Without some, nano-level particles will pass through them.
The skeleton 10 is present in at least one layer on the surface of the monolith filter 100. This one layer has a thickness of 50 nm or more and a micro level.

The first opening 11 is a macro hole. The skeleton 10 has a mesopore, which is a second opening 12, although not shown. Mesopores are continuous throughout the interior of the skeleton 10.
The "macropore" means a pore having a pore diameter (pore diameter) of 50 nm or more according to the proposal by IUPAC, and the "mesopore" means an intermediate between a macropore and a micropore (a pore having a pore diameter of less than 2 nm). That is, it means pores having a pore diameter in the range of 2 nm or more and less than 50 nm.

The pore diameter and average pore diameter are selected based on the expected pore diameter and average pore size size, for example, a general pore distribution measurement by a mercury intrusion method for macropores, a mesopore. Can be obtained by measuring the pore distribution by the nitrogen gas adsorption method.
The monolith refers to a mass of porous body having a skeleton 10 and a void (first opening 11) in succession, and is a functional material that can be applied as an immobilization carrier for a column or a catalyst due to its structural characteristics.

<Outline manufacturing method>
The outline manufacturing method is as follows. A step of preparing a solution containing a compound having a hydrolyzable functional group in a container, and a skeletal phase in which mesopores were formed by proceeding with hydrolysis, polymerization and phase separation of the solution by the sol-gel method. The step of forming a gel having a solution phase and the formed gel are dried to make the skeleton phase the skeleton 10, a mesopore (second opening 12) is formed in the skeleton 10, and the solution phase is macroscopic. It is a method for manufacturing a monolith filter 100 having a hole (first opening 11) and a step of forming the surface in contact with the container so as to be covered with the skeleton 10.

<Detailed manufacturing method>
The monolith filter 100 is obtained by causing a sol-gel transition with phase separation of a reaction solution containing silica as a main component in a container. Precursors of gel-forming network components used in sol-gel reactions include metal alkoxides, complexes, metal salts, organically modified metal alkoxides, organic crosslinked metal alkoxides, and their partial hydrolysis products and partial polymerization products. Can be used as a multimer. The sol-gel transition by changing the pH of water glass or other silicate aqueous solution can also be used in the same manner.

Here, the surface of the vessel needs to be a surface of the opposite nature of the reaction solution. That is, if the reaction solution is hydrophobic, the surface of the container needs to be hydrophilic. 2 (a) and 2 (b) will be described with reference to the cross-sectional view of the container 30.
In the container 30 of FIG. 2A, the sol-gel reaction of the solution 31 is caused. After that, it solidifies by drying and becomes the monolith filter 100 of FIG. 2 (b).

At this time, the surface 21 of the monolith filter 100 is repelled due to the opposite property to the surface of the container 30, and the skeleton 10 is formed on the entire surface 21 as shown in FIG. 2 (c).
In order for the skeleton 10 to be formed, the reaction solution and the surface of the container must have opposite properties. That is, it is necessary that the reaction solution is not regulated on the surface of the container and can be displaced. As described above, it may be hydrophobic and hydrophilic, or it may be an organic reaction solution and an inorganic glass container. If the reaction solution and the surface of the container have the same properties, the reaction solution is restricted and the skeleton 10 cannot be formed or becomes thin.

The surface 21 of the monolith filter 100 that does not come into contact with the container 30 comes into contact with air only. Since air is a free space, as a result, the skeleton 10 cannot be formed on the surface 21 of the monolith filter 100.
FIG. 2C is a cross-sectional view of the formed monolith filter 100 in the column 9. A solution is introduced from the inlet 10 of the column 9 and passed through a monolith filter 100 to remove particles of several nanometers or more in the solution.

At least one surface covered with the skeleton 10 is required for use as a filter. The monolith filter 100 can remove particles at the nano level or higher by the second opening 12 in the skeleton 10.
Further, specifically, in the monolith filter 100, a water-soluble polymer and a thermally decomposable compound are dissolved in an acidic aqueous solution in a container, and a metal compound having a hydrolyzable functional group is added thereto to carry out a hydrolysis reaction. conduct. After the product has solidified, the wet gel is then heated to thermally decompose the small molecule compounds previously dissolved during gel preparation. Then, it is preferably produced by drying and heating.

Here, the water-soluble polymer is a water-soluble organic polymer that can theoretically form an aqueous solution having an appropriate concentration, and is contained in a reaction system containing an alcohol produced by a metal compound having a hydrolyzable functional group. Any substance may be used as long as it can be uniformly dissolved in, but specifically, a sodium salt or a potassium salt of polystyrene sulfonic acid, which is a high molecular weight metal salt, or a polyacrylic acid, which is a high molecular acid and dissociates into a polyanion, is high. Suitable are polyallylamine and polyethyleneimine which are molecular bases and generate polycations in an aqueous solution, polyethylene oxide which is a neutral polymer and has an ether bond in the main chain, and polyvinylpyrrolidone which has a carbonyl group in the side chain. .. Further, a formamide, a polyhydric alcohol, or a surfactant may be used instead of the organic polymer. In that case, glycerin is most suitable as the polyhydric alcohol, and polyoxyethylene alkyl ethers are most suitable as the surfactant.

As the metal compound having a hydrolyzable functional group, a metal alkoxide or an oligomer thereof can be used, and for example, those having a small number of carbon atoms such as a methoxy group, an ethoxy group and a propoxy group are preferable. Further, as the metal, a metal of an oxide finally formed, for example, Si, Ti, Zr, Al is used. The metal may be one kind or two or more kinds. On the other hand, the oligomer may be any oligomer that can be uniformly dissolved and dispersed in alcohol, and specifically, it can be used up to about a dimer.

The acidic aqueous solution is usually preferably one having a concentration of 0.001 mol or more of a mineral acid such as hydrochloric acid or nitric acid, or one having a concentration of 0.01 mol or more of an organic acid such as acetic acid or formic acid.
For phase separation and gelation, the solution is stored at room temperature of 40 to 80 ° C. for 0.5 to 24 hours. It can be achieved by. Phase separation / gelation is a process in which an initially transparent solution becomes cloudy, phase separation between the silica phase and the aqueous phase occurs, and finally gelation occurs. Due to this phase separation and gelation, the water-soluble polymers are in a dispersed state and their precipitation does not occur substantially.

Specific examples of the thermally decomposable compound to be coexisted in advance include urea or hexamethylenetetramine, formamide, N-methylformamide, N, N-dimethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide and the like. However, since the pH value of the solvent after heating is an important condition, there is no particular limitation as long as it is a compound that makes the solvent basic after thermal decomposition.

The amount of the thermally decomposable compound to be coexistent depends on the type of the compound, but in the case of urea, for example, it is 0.05 to 0.8 g, preferably 0.1 to 0.7 g, based on 10 g of the reaction solution. The heating temperature is, for example, 40 to 200 ° C. in the case of urea, and the pH value of the solvent after heating is preferably 6.0 to 12.0. Further, compounds having a property of dissolving silica, such as hydrofluoric acid, which are produced by thermal decomposition can be similarly used.

Even if the monolith filter 100 has a mesopore, it must not be fired to disappear. When the calcination temperature is, for example, 600 degrees or more, the mesopore pore diameter and the pore volume are greatly reduced, which is not good.
<How to use>
A method of using the monolith filter 100 will be described with reference to FIGS. 3 (a) and 3 (b).

FIG. 3A shows a monolith filter 100 fixed to a pipe-shaped column 19. The solution is put in from the inlet 10 and put on a centrifuge. The solution is withdrawn from outlet 15. When the solution passes through the monolith filter 100, particles having a diameter of several nanometers are removed.

The monolith filter 100 has a columnar shape, one surface of which is covered with the skeleton 10, and the other surface of which is a layer in which macropores (first opening 11) are continuous. The monolith filter 100 may be in the form of a sheet. One surface may be covered with the skeleton 10, and the other surface may be a layer in which macropores (first openings 11) are continuous.

FIG. 3B shows a pipe-shaped or columnar monolith filter 100 set in the column 19. The solution is put into the inside of the pipe-shaped monolith filter 100 from the inlet 10. The solution flows through the first opening 11 inside the monolith filter 100 with low resistance and is discharged to the outside from the second opening 12 existing on the outer surface of the monolith filter 100. A few nano particles can be removed from the solution.

It is preferable that the monolith filter 100 at the entrance 10 does not have the skeleton 10. Another usage method will be described with reference to the cross-sectional views of FIGS. 4 (a) and 4 (b).

As another method of use, the monolith filter 100 is provided on the porous body 41. The monolith filter 100 is separately formed into a sheet shape.
That is, the sol-gel reaction of the solution 31 in a solution state is caused in a plane. The flat surface has the opposite properties of the solution, as described above. As a result, a sheet-shaped monolith filter 100 whose surface is covered with the skeleton 10 is formed.

The sheet-shaped monolith filter 100 is arranged on the porous body 41. The porous body 41 is a skeleton that supports the monolith filter 100, and has continuous pores at the micro level or higher. This arrangement is set in the solid-state separator 50a as shown in FIG. 4 (b). This completes the solid separation device 50a as shown in FIG. 3A. The skeleton 10 of the monolith filter 100 is a nano-level filter.

0.80 g of polyethylene oxide (Product No. 85,645-2 manufactured by Aldrich) and 0.90 g of urea, which are water-soluble polymers, are dissolved in 10 g of a 0.01 specified acetic acid aqueous solution, and 4 ml of tetramethoxysilane is stirred in this solution. In addition, a hydrolysis reaction was carried out. After stirring for several minutes, the obtained transparent solution was poured into a glass tube having an inner diameter of 6 mm and kept in a constant temperature bath at 40 ° C., and solidified after about 30 minutes.

The solidified sample was aged for a further few hours and kept at 80 ° C. for 2 hours under closed conditions. After this treatment, the gel was dried at 40 ° C. for 3 days and heated to 800 ° C. at a heating rate of 100 ° C./h to obtain a rod-shaped inorganic porous body having a diameter of 4.5 mm.
It was confirmed that in the obtained porous body, through holes having a central hole diameter of about 3.5 μm (= 3500 nm) were entwined in a three-dimensional network. Then, it was confirmed by nitrogen adsorption measurement that a large number of pores having a diameter of about 9 nm existed on the inner wall of the through hole.

(as a whole)
As the monolith as the monolith filter 100, not only the above silica monolith but also inorganic monoliths of various metal elements can be used.
Organic monoliths (polymer monoliths, polymer monoliths) can also be used. For example, a method of producing a monolith by phase separation from a polymer solution can be used by utilizing the fact that the acrylic resin is specifically dissolved in a water / alcohol mixed solvent. Specifically, polymethyl methacrylate resin (PMMA) can be dissolved by heating in a mixed solvent of water and ethanol (ethanol 80 vol%), and the solution can be cooled to obtain a monolith having a submicron-sized skeleton 10. can. In addition, various organic monoliths can be used.

It can be used if the skeleton 10 can be formed on the surface of the monolith filter 100. In the case of organic monoliths, the hydrophobicity and hydrophilicity change depending on the raw materials and additives. However, unlike the silica monolith described above, it is easy to form a surface layer covered with the skeleton 10 regardless of the properties. This is probably because the organic monolith has an organic skeleton unlike the silica monolith, so that the surface 21 can be displaced and the skeleton 10 is formed without being restricted by the container.

Unlike inorganic monoliths, organic monoliths are flexible and easy to set on columns. Furthermore, a monolith in which an organic monolith and an inorganic monolith are mixed can also be used. It can be formed by mixing at the solution stage.
Examples of organic monoliths are shown below.

Examples of organic monoliths

15 ml of triethylene glycol, 1.5 ml of 1,3,5-trimethylbenzene, 1.5 ml of benzyl alcohol and 2.5 ml of 1M hydrochloric acid are mixed, and 1.5 g of block copolymer F127 (EO ₁₀₆ PO ₇₀ EO ₁₀₆ ) and resorcinol are mixed therein. Add 1.1 g and stir well to make a uniform solution. Add 1.5 ml of formamide (37%) to this and stir. The obtained solution was placed in a glass container and held at 60 ° C. for 48 hours to prepare a polymer monolith having macropores and mesopores. The macropore diameter of the produced polymer monolith was 2 μm, and the mesopore diameter was 5 nm. FIG. 5 shows an SEM photograph of the portion of the surface of the obtained polymer monolith in contact with the glass. A skeleton layer having a thickness of about 3 μm can be uniformly formed. There are no macropores in this skeletal layer, only mesopores of 5 nm.

According to the monolith filter of the present invention and the method for producing the same, a nano-level filter can be provided. Nano-level particles can be removed from various solutions. For example, it can be used for purification of bio-related solutions.

9, 19 ... column, 10 ... skeleton, 11 ... first opening, 12 ... second opening, 15 ... outlet, 21 ... surface, 30 ... container, 31 ... solution, 40-80 ... room temperature, 41 ... porous body, 50a ... Solid separator, 100 ... Monolith filter, filter.

Claims (9)

A skeleton with mesopores and
A monolith filter containing macropores existing between the skeletons.
At least one surface of the monolith filter is a monolith filter covered with the skeleton.
The one side is a monolith filter, which is the side through which the solution passes.
On the one side, there is a meso hole without the macro hole, and there is a meso hole.
A monolith filter for solid separation consisting only of monoliths. The monolith filter according to claim 1, wherein one surface of the surface is formed only of the skeleton. A skeleton with mesopores and
A monolith filter containing macropores existing between the skeletons.
At least one surface of the monolith filter is a monolith filter covered with the skeleton.
The monolith filter has a columnar shape, its side surface is covered with the skeleton, and the inside thereof is a monolith filter in which macropores are continuously present.
On the one side, there is a meso hole without the macro hole, and there is a meso hole.
The one side is the side through which the solution passes.
A monolith filter for solid separation that is only a monolith. A skeleton with mesopores and
A monolith filter containing macropores existing between the skeletons.
At least one surface of the monolith filter is a monolith filter covered with the skeleton.
The monolith filter is in the form of a sheet, one surface of which is covered with the skeleton, and the other surface is a monolith filter in which macropores are continuously present.
There is a meso hole on the one side without the macro hole.
The one side is the side through which the solution passes.
A monolith filter for solid separation consisting only of monoliths. A solid-state separation device in which one surface of the monolith filter according to any one of claims 1 to 4 is used as a passing surface for the solution . A solid separation device in which the monolith filter according to any one of claims 1 to 4 is laminated with a porous body. A skeleton with mesopores and
A monolith filter containing macropores existing between the skeletons.
At least one surface of the monolith filter is covered with the skeleton.
It has a pipe-shaped column in which the monolith filter is arranged, and has.
The solution is a solid separation device having the one side of the monolith filter as a passing surface.
Inside the monolith filter, macro holes are continuously present, and
The other surface of the monolith filter is a solid separation device in which macropores are continuously present, one surface is a surface through which a solution passes, and the one surface does not have the macropores but has mesopores. Solid separation device. The solid separation device according to claim 7, wherein one surface of the surface is formed only of the skeleton. The step of preparing a solution containing a compound having a hydrolyzable functional group in a container, and
A step of advancing hydrolysis and polymerization of the above solution by the sol-gel method and phase separation to form a gel having a skeletal phase in which mesopores are formed and a solution phase.
A step of drying the formed gel to form the skeletal phase as a skeleton, forming mesopores in the skeleton, macropores in the solution phase, and forming the surface in contact with the container so as to be covered with the skeleton. Is a manufacturing method of a monolith filter having,
One of the container and the solution is hydrophobic and the other is hydrophilic.
The surface does not have the macropores but has mesopores, and is a method for manufacturing a monolith filter for solid separation.

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