JP7414636B2 - Gas adsorbent, method for producing the gas adsorbent, and gas adsorption method - Google Patents

Description

The present invention relates to a gas adsorbent, a method for producing the gas adsorbent, and a method for gas adsorption.

Foul-smelling gases and gases that cause air pollution are regulated by the Offensive Odor Prevention Act, the Air Pollution Control Act, the Building Standards Act, etc. because they cause pollution and health damage. For example, aldehyde gases such as acetaldehyde and formaldehyde are considered to be the cause of sick building syndrome, and there is a strong demand for their removal. On the other hand, for example, Patent Document 1 proposes that a compound having an amino group and/or an imino group be supported in the pores of a porous silica material as an adsorbent for aldehyde gas.

However, the adsorbent described above may not have sufficient adsorption ability for malodorous gases other than aldehyde gases.

JP2009-82786A

The present invention has been made to solve the above problems, and one of its objects is to provide a gas adsorbent that can exhibit excellent adsorption ability for various gases.

According to one aspect of the invention, a gas adsorbent is provided. This gas adsorbent is composed of a porous body containing a metal silicate, and has amino groups supported on the porous body, and the amount of the amino groups contained in 1 g is 3 mmol or less.
In one embodiment, the SiO ₂ content of the gas adsorbent is 75% by weight or less.
In one embodiment, the content of SiO ₂ in the gas adsorbent is 35% by weight or more.
In one embodiment, the porous body includes an amorphous metal silicate.
In one embodiment, the metal silicate comprises magnesium silicate.
In one embodiment, the amount of amino groups contained in 1 g of the gas adsorbent is 0.1 mmol or more.
In one embodiment, the amount of amino groups contained in 1 g of the gas adsorbent is 2 mmol or less.
In one embodiment, the gas adsorbent has a BET specific surface area of 200 m ² /g or more.
In one embodiment, the gas adsorbent has a mesopore volume of 0.35 cm ³ /g or more.
In one embodiment, the total pore volume of the gas adsorbent is 0.4 cm ³ /g or more.
In one embodiment, the ratio of mesopore volume to total pore volume (mesopore volume/total pore volume) of the gas adsorbent is 0.75 or more.
In one embodiment, the gas adsorbent has at least one peak in a pore size range of 10 nm or less in the pore distribution determined by the BJH method.

According to another aspect of the present invention, a method for manufacturing the above gas adsorbent is provided. This manufacturing method includes obtaining a first liquid containing a reaction product of a precursor of a porous body containing the metal silicate and an amino group-containing compound, and drying the first liquid. include.
In one embodiment, the first liquid is dried by a spray drying method.

According to yet another aspect of the invention, a method of gas adsorption is provided. This gas adsorption method includes bringing a gas into contact with the gas adsorbent.

According to yet another aspect of the invention, a deodorizing product is provided. This deodorizing product contains the gas adsorbent described above.

According to the present invention, by supporting an amino group on a porous body containing a metal silicate, it can be provided with excellent adsorption ability for various gases.

It is an electron microscope observation photograph (2000 times) of Example 3. 3 is a graph showing the pore distribution measurement results of Example 3. It is an electron microscope observation photograph (2000 times) of Comparative Example 3. It is an electron microscope observation photograph (2000 times) of Example 4. 3 is a graph showing the pore distribution measurement results of Example 4. This is an electron microscope observation photograph (2000 times) of Comparative Example 4.

Embodiments of the present invention will be described below, but the present invention is not limited to these embodiments.

A. Gas Adsorbent The gas adsorbent in one embodiment of the present invention is composed of a porous body containing a metal silicate, and has an amino group supported on the porous body. Specifically, the gas adsorbent in one embodiment of the present invention is configured by using a porous body containing a metal silicate as a carrier, and having an amino group supported on the carrier.

The BET specific surface area of the gas adsorbent is preferably 200 m ² /g or more, more preferably 300 m ² /g or more, particularly preferably 400 m ² /g or more. With such a BET specific surface area, sufficient gas adsorption sites can be secured and higher gas adsorption ability can be achieved. On the other hand, the BET specific surface area of the gas adsorbent is, for example, 900 m ² /g or less.

The mesopore volume of the gas adsorbent is preferably 0.35 cm ³ /g or more, more preferably 0.4 cm ³ /g or more. With such a mesopore volume, sufficient gas adsorption sites can be secured and higher gas adsorption capacity can be achieved. On the other hand, the mesopore volume of the gas adsorbent is, for example, 1.5 cm ³ /g or less. Note that the mesopore volume is an integrated value of the pore volumes of pores with a diameter of 1 nm to 100 nm, which is determined by pore distribution analysis using the BJH method.

In one embodiment, the mesopore volume of the gas adsorbent is preferably 0.35 cm ³ /g or more, more preferably 0.4 cm ³ /g or more, particularly preferably 0.6 cm ³ /g or more. .

The total pore volume of the gas adsorbent is preferably 0.4 cm ³ /g or more, more preferably 0.5 cm ³ /g or more. With such a total pore volume, sufficient gas adsorption sites can be secured and higher gas adsorption capacity can be achieved. On the other hand, the total pore volume of the gas adsorbent is, for example, 2.0 cm ³ /g or less. Note that the total pore volume is the total volume of all pores, and is determined from the maximum adsorption amount by the one-point method at the maximum relative pressure in the gas adsorption method.

In one embodiment, the total pore volume of the gas adsorbent is preferably 0.4 cm ³ /g or more, more preferably 0.5 cm ³ /g or more, particularly preferably 0.7 cm ³ /g or more. .

The ratio of the mesopore volume to the total pore volume (mesopore volume/total pore volume) is preferably 0.75 or more, more preferably 0.8 or more, particularly preferably 0.9 or more. . With such a ratio, the gas adsorption ability (for example, for aldehyde gases) can be improved. Specifically, the presence of mesopores can greatly contribute to the adsorption of gases (eg, aldehyde gases).

It is preferable that the gas adsorbent has at least one peak in the pore diameter range of 10 nm or less in the pore distribution determined by the BJH method. Such a pore distribution provides superior gas adsorption ability (for example, for aldehyde gases).

The gas adsorbent may be in any suitable form. In one embodiment, the gas adsorbent is in the form of particles (powder) from the viewpoint of ease of handling. In this case, the angle of repose of the gas adsorbent is preferably 25° to 40°, more preferably 27° to 37°.

The content of SiO ₂ in the gas adsorbent is, for example, 75% by weight or less, preferably 70% by weight or less. On the other hand, the content of SiO ₂ is preferably 35% by weight or more, more preferably 40% by weight or more, particularly preferably 50% by weight or more. According to such a SiO ₂ content, the adsorption ability for various gases can be improved. For example, it has an excellent balance between the metal salt and SiO ₂ described below (specifically, the content ratio of the metal salt and SiO ₂ is not biased to either side), and has excellent adsorption ability for various gases.

In one embodiment, the adsorption capacity for various gases is controlled by adjusting the content of SiO ₂ . Specifically, the content of SiO ₂ is adjusted depending on the type of gas to be adsorbed.

A-1. Porous Body The porous body is formed of metal silicate. The content of metal silicate in the porous body is, for example, 93% by weight or more, preferably 95% by weight or more, and more preferably 97% by weight or more. According to such a content, an adverse effect on the components combined with the gas adsorbent, various products obtained using the gas adsorbent (for example, deodorizing products), etc. can be suppressed. Specifically, the elution of impurities (eg, alkali salts) contained in the gas adsorbent is suppressed. As a result, it is possible to suppress deterioration of the physical properties of components combined with the gas adsorbent, various products obtained using the gas adsorbent, etc. due to elution of impurities.

The metal silicate is a metal salt of silicic acid (SiO ₂ ). Examples of metal silicates include magnesium silicate, aluminum silicate, zinc silicate, calcium silicate, copper silicate, iron silicate, and complexes thereof. These may be used alone or in combination of two or more. Among these, at least one selected from the group consisting of magnesium silicate, aluminum silicate, and zinc silicate is preferably used, and magnesium silicate is more preferably used. For example, it is easy to handle and is easily available.

In one embodiment, the adsorption capacity for various gases is controlled by adjusting the content ratio (for example, molar ratio) of the metal salt and SiO ₂ . Specifically, the content ratio of the metal salt and SiO ₂ is adjusted depending on the type of gas to be adsorbed.

The metal silicate can be represented by the following general formula (I), for example.
x(M _m O _n )・y(SiO ₂ )・z(H ₂ O)...(I)
(In formula (I), M is a metal, y/x is 0.5 or more and 14 or less, n/m is 1.0 or 1.5, and z is 0 or more and 5.0 or less.)

In the above general formula (I), M represents a divalent or trivalent metal. Preferably, M represents one or a combination of two or more selected from the group consisting of Mg, Al, Zn, Ca, Cu and Fe. M preferably represents one or a combination of two or more selected from the group consisting of Mg, Al, and Zn, and more preferably represents Mg.

In the above general formula (I), y/x is preferably 1.0 or more, more preferably 2.0 or more, and still more preferably 3.0 or more. On the other hand, y/x is preferably 13 or less, more preferably 7.5 or less.

In the above general formula (I), z is preferably 0.5 or more, more preferably 1.0 or more. On the other hand, z is preferably 4.0 or less, more preferably 3.5 or less.

The porous body is preferably formed of an amorphous metal silicate. By employing such a configuration, for example, the specific surface area, pore volume (especially mesopore volume), and pore distribution described above can be satisfactorily satisfied. Specifically, amorphous metal silicate allows the primary particles to be made very small. Furthermore, amorphous metal silicates tend to have many mesopores, whereas crystalline metal silicates tend to have many micropores. Here, "mesopores" refer to pores with a diameter of 1 nm to 100 nm. Moreover, confirmation that it is amorphous can be performed, for example, by measurement using an X-ray diffraction device (XRD measurement).

A-2. Amino Group As mentioned above, the gas adsorbent has an amino group supported on the porous body. By having an amino group, for example, the adsorption ability for aldehyde gases can be excellent. Specifically, aldehyde gases react with amino groups and are chemically adsorbed, and problems that occur in the case of physical adsorption (for example, the adsorbed gas may be desorbed from the gas adsorbent over time due to conditions such as temperature and pressure). ) may be suppressed. Note that physical adsorption typically includes adsorption due to van der Waals force.

The amount of amino groups contained in 1 g of gas adsorbent can be adjusted as appropriate, for example, depending on the metal silicate contained in the porous body. The amount of amino groups contained in 1 g of gas adsorbent is, for example, 0.1 mmol or more, preferably 0.4 mmol or more, and more preferably 0.8 mmol or more. On the other hand, the amount of amino groups contained in 1 g of gas adsorbent is 3 mmol or less, preferably 2.5 mmol or less, more preferably 2 mmol or less, particularly preferably 1.5 mmol or less. By having such an amount of amino groups, for example, the above-mentioned specific surface area and pore volume can be satisfactorily satisfied. Note that the amount of supported amino groups can be measured using the Kjeldahl method.

In one embodiment, the amount of amino groups contained in 1 g of gas adsorbent is 2.5 mmol or less, preferably 2 mmol or less.

By adjusting the amount of amino groups, the adsorption ability for various gases can be controlled. In one embodiment, the amount of gas (e.g., acidic gas and/or basic gas) adsorbed by the porous material (e.g., basic substance and/or acidic substance) that is the carrier is reduced by suppressing the amount of amino groups. increase.

Typically, the amino group is supported on the porous body using an amino group-containing compound. Any suitable compound may be used as the amino group-containing compound. In one embodiment, an amino group-containing silicon compound is used as the amino group-containing compound.

As the amino group-containing silicon compound, a compound (for example, a silane coupling agent) having an amino group and a functional group capable of bonding to a functional group (typically, a hydroxyl group) on the surface of the porous body is preferably used. It will be done. Specific examples of such compounds include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl )-3-aminopropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine, N-phenyl -3-aminopropyltrimethoxysilane is mentioned. These may be used alone or in combination of two or more. Among these, for example, 3-aminopropyltriethoxysilane is preferably used from the viewpoint of cost.

A-3. Manufacturing method Any suitable method may be employed as the method for manufacturing the gas adsorbent. In one embodiment, the method for producing the gas adsorbent includes obtaining a first liquid containing a reaction product of the precursor of the porous body containing the metal silicate and the amino group-containing compound; , drying the first liquid.

The precursor of the porous body containing the metal silicate can be produced by any suitable method. For example, a precursor of a porous body containing a metal silicate is a coprecipitate obtained using an aqueous solution of a metal salt and an aqueous alkali silicate solution. As the metal salt, preferably used are soluble metal salts such as sulfates, nitrates, and chlorides. Examples of the alkali silicate aqueous solution include sodium orthosilicate aqueous solution, sodium metasilicate aqueous solution, sodium silicate aqueous solution, potassium silicate aqueous solution, and water glass.

When obtaining the above-mentioned coprecipitate (during the coprecipitation reaction), a coprecipitation liquid may be used. Specifically, a coprecipitate is obtained by adding the metal salt aqueous solution and the alkali silicate aqueous solution to a coprecipitation liquid (typically water). When a coprecipitation liquid is not used, a coprecipitate is obtained by adding the other aqueous solution to either the metal salt aqueous solution or the alkali silicate aqueous solution. In addition, when adding the aqueous solution, it is preferable that the liquid to be added be stirred.

Typically, the pH value is adjusted during the coprecipitation reaction. The pH value during the coprecipitation reaction is adjusted, for example, depending on the type of metal salt used. Specifically, when the metal salt contains magnesium, it is adjusted within the range of 9.0 to 12.0. When the metal salt contains aluminum, it is adjusted within the range of 3.0 to 5.0. When the metal salt contains zinc, it is adjusted within the range of 5.5 to 7.5.

In one embodiment, the coprecipitate is subjected to appropriate treatments such as dehydration and washing, and the coprecipitate is dispersed in a dispersion medium (typically water) to form a dispersion (suspension). do. The dispersion may further be subjected to heat treatment.

Water is typically used as the dispersion medium. Further, the heating temperature of the dispersion is preferably 60°C to 200°C, more preferably 80°C to 170°C. The heating time is, for example, 2 hours to 20 hours.

When preparing the first liquid, the amino group-containing compound is preferably in the form of a solution or dispersion in advance. For example, by mixing the dispersion and a solution or dispersion of an amino group-containing compound, and reacting the precursor of the porous body containing the metal silicate with the amino group-containing compound, the first liquid get.

Any suitable drying method may be adopted as the method for drying the first liquid. Preferably, a spray drying method is employed. By employing the spray drying method, for example, a dried product (gas adsorbent) that is easy to handle can be obtained. For example, a dry product with a low angle of repose can be obtained.

The drying temperature of the first liquid is, for example, 100°C to 140°C.

By drying the first liquid, amino groups (amino group-containing compounds) can be supported on the porous body containing the metal silicate. According to such a method, substantially all of the amino groups (amino group-containing compound) contained in the first liquid can be supported on the porous body containing the metal silicate. Therefore, by adjusting the content of the amino group-containing compound in the first liquid, a gas adsorbent having a desired supported amount can be obtained.

A-4. Method of Use A gas adsorption method in one embodiment of the present invention uses the above gas adsorbent. Specifically, it includes bringing a gas into contact with the gas adsorbent. Gas contact is typically carried out with the gas adsorbent contained in a filter, sheet-like product, paint, fiber, resin molded product, or the like.

The gas to be contacted may contain various malodorous gases. Examples of malodorous gases include neutral malodorous gases such as aldehyde gases (e.g. formaldehyde, acetaldehyde); acidic malodorous gases such as acetic acid, hydrogen sulfide, and mercaptans; basic malodorous gases such as ammonia and amines (e.g. trimethylamine). Examples include foul-smelling gas.

The gas adsorbent can exhibit excellent adsorption ability for various gases. Specifically, in addition to the above-mentioned aldehyde gases, it can exhibit excellent adsorption ability for acidic malodorous gases and/or basic malodorous gases.

According to the gas adsorbent, the adsorption ability for various gases can be controlled by, for example, adjusting various properties such as the composition, amount of amino groups, specific surface area, and pores of the metal silicate. Specifically, the adsorption capacity for aldehyde gases and the adsorption capacity for acidic gases and/or basic gases can be controlled. Note that the specific surface area and pores can be controlled, for example, by the method for producing the metal silicate.

According to the gas adsorbent, for example, compared to a case where two or more types of adsorbents with different configurations are mixed to adsorb various gases, uniformity in adsorption characteristics and quality can be excellent.

EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited to these Examples.

[Example 1-1]
While stirring the ion-exchanged water in the reaction vessel, a magnesium sulfate aqueous solution (1.36 mol/L) and a No. 3 water glass aqueous solution (Na ₂ O: 0.55 mol/L, SiO ₂ : 1.73 mol/L) were added thereto. ) were added at the same time to cause a coprecipitation reaction. The temperature during the coprecipitation reaction was 30°C, and the pH was 10.4.
The resulting coprecipitate was dehydrated and washed with water, then resuspended in ion-exchanged water, and the resulting suspension was stirred while heating at 90° C. for 2 hours.

While stirring 1 L of the above heated and stirred suspension (solid content concentration: 292 g/L) at room temperature, 3-aminopropyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., "KBE-903") was added to it. 650 mL of 5 wt % aqueous solution was added.
Next, the suspension was spray-dried to obtain a dried product containing an amorphous hydrated magnesium silicate compound (molar ratio (SiO ₂ /MgO): 3.69).

[Example 1-2]
While stirring the ion-exchanged water in the reaction vessel, a magnesium sulfate aqueous solution (1.36 mol/L) and a No. 3 water glass aqueous solution (Na ₂ O: 0.55 mol/L, SiO ₂ : 1.73 mol/L) were added thereto. ) were added at the same time to cause a coprecipitation reaction. The temperature during the coprecipitation reaction was 30°C, and the pH was 10.4.
The resulting coprecipitate was dehydrated and washed with water, then resuspended in ion-exchanged water, and the resulting suspension was stirred while heating at 90° C. for 2 hours.

While stirring 700 mL of the above heated and stirred suspension (solid content concentration: 292 g/L) at room temperature, 3-aminopropyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., "KBE-903") was added to it. 1.02 L of 5 wt % aqueous solution was added.
Next, the suspension was spray-dried to obtain a dried product containing an amorphous hydrated magnesium silicate compound (molar ratio (SiO ₂ /MgO): 3.81).

[Comparative example 1]
While stirring the ion-exchanged water in the reaction vessel, a magnesium sulfate aqueous solution (1.36 mol/L) and a No. 3 water glass aqueous solution (Na ₂ O: 0.55 mol/L, SiO ₂ : 1.73 mol/L) were added thereto. ) were added at the same time to cause a coprecipitation reaction. The temperature during the coprecipitation reaction was 30°C, and the pH was 10.4.
The resulting coprecipitate was dehydrated and washed with water, then resuspended in ion-exchanged water, and the resulting suspension was stirred while heating at 90° C. for 2 hours.
Thereafter, the suspension was dehydrated and washed with water, and then dried in a hot air dryer for 15 hours to obtain a dried product containing an amorphous hydrated magnesium silicate compound (molar ratio (SiO ₂ /MgO): 3.58). Obtained.

[Example 2-1]
While stirring the ion-exchanged water in the reaction vessel, a magnesium sulfate aqueous solution (1.36 mol/L) and a No. 3 water glass aqueous solution (Na ₂ O: 0.55 mol/L, SiO ₂ : 1.73 mol/L) were added thereto. ) were added at the same time to cause a coprecipitation reaction. The temperature during the coprecipitation reaction was 30°C, and the pH was 10.3.
The resulting coprecipitate was dehydrated and washed with water, then resuspended in ion-exchanged water, and the resulting suspension was stirred while heating at 90° C. for 2 hours.

While stirring 1 L of the above heated and stirred suspension (solid concentration: 293 g/L) at room temperature, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane (Shin-Etsu Chemical Co., Ltd. 650 mL of a 5 wt % aqueous solution of "KBM-603" (manufactured by KBM-603) was added.
Next, the suspension was spray-dried to obtain a dried product containing an amorphous hydrated magnesium silicate compound (molar ratio (SiO ₂ /MgO): 3.59).

[Example 2-2]
While stirring the ion-exchanged water in the reaction vessel, a magnesium sulfate aqueous solution (1.36 mol/L) and a No. 3 water glass aqueous solution (Na ₂ O: 0.55 mol/L, SiO ₂ : 1.73 mol/L) were added thereto. ) were added at the same time to cause a coprecipitation reaction. The temperature during the coprecipitation reaction was 30°C, and the pH was 10.3.
The resulting coprecipitate was dehydrated and washed with water, then resuspended in ion-exchanged water, and the resulting suspension was stirred while heating at 90° C. for 2 hours.

N-2-(aminoethyl)-3-aminopropyltrimethoxysilane (Shin-Etsu Chemical Co., Ltd.) was added to 700 mL of the above heated and stirred suspension (solid concentration: 293 g/L) while stirring at room temperature. 1.03 L of a 5 wt % aqueous solution of "KBM-603" (manufactured by KBM-603) was added.
Next, the suspension was spray-dried to obtain a dried product containing an amorphous hydrated magnesium silicate compound (molar ratio (SiO ₂ /MgO): 3.87).

[Comparative example 2-1]
While stirring the ion-exchanged water in the reaction vessel, a magnesium sulfate aqueous solution (1.36 mol/L) and a No. 3 water glass aqueous solution (Na ₂ O: 0.55 mol/L, SiO ₂ : 1.73 mol/L) were added thereto. ) were added at the same time to cause a coprecipitation reaction. The temperature during the coprecipitation reaction was 30°C, and the pH was 10.3.
The resulting coprecipitate was dehydrated and washed with water, then resuspended in ion-exchanged water, and the resulting suspension was stirred while heating at 90° C. for 2 hours.
Thereafter, the suspension was dehydrated and washed with water, and then dried in a hot air dryer for 15 hours to obtain a dried product containing an amorphous hydrated magnesium silicate compound (molar ratio (SiO ₂ /MgO): 3.64). Obtained.

[Comparative example 2-2]
While stirring the ion-exchanged water in the reaction vessel, a magnesium sulfate aqueous solution (1.36 mol/L) and a No. 3 water glass aqueous solution (Na ₂ O: 0.55 mol/L, SiO ₂ : 1.73 mol/L) were added thereto. ) were added at the same time to cause a coprecipitation reaction. The temperature during the coprecipitation reaction was 30°C, and the pH was 10.3.
The resulting coprecipitate was dehydrated and washed with water, then resuspended in ion-exchanged water, and the resulting suspension was stirred while heating at 90° C. for 2 hours.

N-2-(aminoethyl)-3-aminopropyltrimethoxysilane (Shin-Etsu Chemical Co., Ltd. 1.37 L of a 5 wt % aqueous solution of ``KBM-603'' (manufactured by Kogyo Co., Ltd.) was added.
Next, the suspension was spray-dried to obtain a dried product containing an amorphous hydrated magnesium silicate compound (molar ratio (SiO ₂ /MgO): 3.77).

[Example 3]
While stirring the ion-exchanged water in the reaction vessel, a magnesium sulfate aqueous solution (1.36 mol/L) and a No. 3 water glass aqueous solution (Na ₂ O: 0.55 mol/L, SiO ₂ : 1.73 mol/L) were added thereto. ) were added at the same time to cause a coprecipitation reaction. The temperature during the coprecipitation reaction was 30°C, and the pH was 10.5.
The resulting coprecipitate was dehydrated and washed with water, then resuspended in ion-exchanged water, and the resulting suspension was stirred while heating at 120° C. for 15 hours.

While stirring 500 mL of the above heated and stirred suspension (solid content concentration: 313 g/L) at room temperature, 3-aminopropyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., "KBE-903") was added to it. 780 mL of 5 wt % aqueous solution was added.
Next, the suspension was spray-dried to obtain a dried product containing an amorphous hydrated magnesium silicate compound (molar ratio (SiO ₂ /MgO): 3.95).

[Comparative example 3]
While stirring the ion-exchanged water in the reaction vessel, a magnesium sulfate aqueous solution (1.36 mol/L) and a No. 3 water glass aqueous solution (Na ₂ O: 0.55 mol/L, SiO ₂ : 1.73 mol/L) were added thereto. ) were added at the same time to cause a coprecipitation reaction. The temperature during the coprecipitation reaction was 30°C, and the pH was 10.5.
The resulting coprecipitate was dehydrated and washed with water, then resuspended in ion-exchanged water, and the resulting suspension was stirred while heating at 120° C. for 15 hours.
Thereafter, the suspension was dehydrated and washed with water, and then dried in a hot air dryer for 15 hours to obtain a dried product containing an amorphous hydrated magnesium silicate compound (molar ratio (SiO ₂ /MgO): 3.61). Obtained.

[Example 4]
While stirring the ion-exchanged water in the reaction vessel, a magnesium sulfate aqueous solution (0.45 mol/L) and a sodium silicate aqueous solution (Na ₂ O: 0.6 mol/L, SiO ₂ : 0.95 mol/L) were added thereto. were added at the same time to cause a coprecipitation reaction. The temperature during the coprecipitation reaction was 30°C, and the pH was 11.2.
The resulting coprecipitate was dehydrated and washed with water, then resuspended in ion-exchanged water, and the resulting suspension was stirred while heating at 180° C. for 15 hours.

While stirring 700 mL of the above heated and stirred suspension (solid content concentration: 148 g/L) at room temperature, 3-aminopropyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., "KBE-903") was added to it. 520 mL of 5 wt % aqueous solution was added.
Next, the suspension was spray-dried to obtain a dried product containing an amorphous hydrated magnesium silicate compound (molar ratio (SiO ₂ /MgO): 2.11).

[Comparative example 4]
While stirring the ion-exchanged water in the reaction vessel, a magnesium sulfate aqueous solution (0.45 mol/L) and a sodium silicate aqueous solution (Na ₂ O: 0.6 mol/L, SiO ₂ : 0.95 mol/L) were added thereto. were added at the same time to cause a coprecipitation reaction. The temperature during the coprecipitation reaction was 30°C, and the pH was 11.2.
The resulting coprecipitate was dehydrated and washed with water, then resuspended in ion-exchanged water, and the resulting suspension was stirred while heating at 180° C. for 15 hours.
Thereafter, the suspension was dehydrated and washed with water, and then dried in a hot air dryer for 15 hours to obtain a dried product containing an amorphous hydrated magnesium silicate compound (molar ratio (SiO ₂ /MgO): 1.83). Obtained.

[Example 5]
While stirring the ion-exchanged water in the reaction vessel, a mixed solution of 630 mL of magnesium sulfate aqueous solution (0.79 mol/L) and 242 mL of sulfuric acid (1.86 mol/L) and No. 3 water glass aqueous solution (Na ₂ 1.744 L of O: 0.57 mol/L, SiO ₂ : 1.8 mol/L) were added at the same time to cause a coprecipitation reaction. The temperature during the coprecipitation reaction was 30°C, and the pH was 9.7.
The resulting coprecipitate was dehydrated and washed with water, then resuspended in ion-exchanged water, and the resulting suspension was stirred while heating at 90° C. for 2 hours.

While stirring 500 mL of the above heated and stirred suspension (solid content concentration: 132 g/L) at room temperature, 3-aminopropyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., "KBE-903") was added to it. 330 mL of 5 wt % aqueous solution was added.
Next, the suspension was spray-dried to obtain a dried product containing an amorphous hydrated magnesium silicate compound (molar ratio (SiO ₂ /MgO): 7.79).

[Example 6]
While stirring the ion-exchanged water in a reaction vessel, 1.377 L of a magnesium sulfate aqueous solution (2.18 mol/L) and 1.377 L of a sodium orthosilicate aqueous solution (Na ₂ O: 2 mol/L, SiO ₂ : 1 mol/L) were added. .5L was added at the same time to cause a coprecipitation reaction. The temperature during the coprecipitation reaction was 30°C, and the pH was 10.6.
The resulting coprecipitate was dehydrated and washed with water, then resuspended in ion-exchanged water, and the resulting suspension was stirred while heating at 90° C. for 2 hours.

While stirring 500 mL of the above heated and stirred suspension (solid content concentration: 156 g/L) at room temperature, 3-aminopropyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., "KBE-903") was added to it. 390 mL of 5 wt % aqueous solution was added.
Next, the suspension was spray-dried to obtain a dried product containing an amorphous hydrated magnesium silicate compound (molar ratio (SiO ₂ /MgO): 0.65).

[Comparative example 5]
A suspension was obtained by suspending 100 g of silica gel (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd., "Wako Gel C-500HG", 5-20 μm crushed) in 500 mL of ion-exchanged water.
While stirring the resulting suspension at room temperature, 500 mL of a 5 wt% aqueous solution of 3-aminopropyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., "KBE-903") was added.
Next, the suspension was spray dried to obtain a dried product containing an amorphous hydrated silicic acid compound.

[Example A-1]
While stirring the ion-exchanged water in the reaction vessel, an aluminum sulfate aqueous solution (0.16 mol/L) and a No. 3 water glass aqueous solution (Na ₂ O: 0.8 mol/L, SiO ₂ : 2.53 mol/L) were added thereto. ) were added at the same time to cause a coprecipitation reaction. The temperature during the coprecipitation reaction was 30°C, and the pH was 4.
The resulting coprecipitate was dehydrated and washed with water, then resuspended in ion-exchanged water, and the resulting suspension was stirred while heating at 95° C. for 4 hours.

While stirring 1 L of the above heated and stirred suspension (solid content concentration: 113 g/L) at room temperature, 3-aminopropyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., "KBE-903") was added to it. 1.22 L of 5 wt % aqueous solution was added.
Next, the suspension was spray-dried to obtain a dried product containing an amorphous hydrous aluminum silicate compound (molar ratio (SiO ₂ /Al ₂ O ₃ ): 12.7).

[Example A-2]
While stirring the ion-exchanged water in the reaction vessel, an aluminum sulfate aqueous solution (0.16 mol/L) and a No. 3 water glass aqueous solution (Na ₂ O: 0.8 mol/L, SiO ₂ : 2.53 mol/L) were added thereto. ) were added at the same time to cause a coprecipitation reaction. The temperature during the coprecipitation reaction was 30°C, and the pH was 4.
The resulting coprecipitate was dehydrated and washed with water, then resuspended in ion-exchanged water, and the resulting suspension was stirred while heating at 95° C. for 4 hours.

While stirring 700 mL of the above heated and stirred suspension (solid content concentration: 113 g/L) at room temperature, 3-aminopropyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., "KBE-903") was added to it. 1.58 L of 5 wt % aqueous solution was added.
Next, the suspension was spray-dried to obtain a dried product containing an amorphous hydrous aluminum silicate compound (molar ratio (SiO ₂ /Al ₂ O ₃ ): 12.8).

[Comparative example A-1]
While stirring the ion-exchanged water in the reaction vessel, an aluminum sulfate aqueous solution (0.16 mol/L) and a No. 3 water glass aqueous solution (Na ₂ O: 0.8 mol/L, SiO ₂ : 2.53 mol/L) were added thereto. ) were added at the same time to cause a coprecipitation reaction. The temperature during the coprecipitation reaction was 30°C, and the pH was 4.
The resulting coprecipitate was dehydrated and washed with water, then resuspended in ion-exchanged water, and the resulting suspension was stirred while heating at 95° C. for 4 hours.
Thereafter, the suspension was dehydrated and washed with water, and then dried in a hot air dryer for 15 hours to form a solution containing an amorphous hydrated aluminum silicate compound (molar ratio (SiO ₂ /Al ₂ O ₃ ): 10.3). A dried product was obtained.

[Example B-1]
While stirring the ion-exchanged water in the reaction vessel, a zinc chloride aqueous solution (0.4 mol/L) and a No. 1 water glass aqueous solution (Na ₂ O: 0.4 mol/L, SiO ₂ : 0.84 mol/L) were added thereto. ) were added at the same time to cause a coprecipitation reaction. The temperature during the coprecipitation reaction was 30°C, and the pH was 6.2.
The obtained coprecipitate was dehydrated and washed with water, and then resuspended in ion-exchanged water.

While stirring 500 mL of the above suspension (solid content concentration: 194 g/L) at room temperature, a 5 wt% aqueous solution of 3-aminopropyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., "KBE-903") was added. 485 mL was injected.
Next, the suspension was spray-dried to obtain a dried product containing an amorphous hydrated zinc silicate compound (molar ratio (SiO ₂ /ZnO): 2.3).

[Comparative example B-1]
While stirring the ion-exchanged water in the reaction vessel, a zinc chloride aqueous solution (0.4 mol/L) and a No. 1 water glass aqueous solution (Na ₂ O: 0.4 mol/L, SiO ₂ : 0.84 mol/L) were added thereto. ) were added at the same time to cause a coprecipitation reaction. The temperature during the coprecipitation reaction was 30°C, and the pH was 6.2.
The obtained coprecipitate was dehydrated and washed with water, and then dried in a hot air dryer for 15 hours to obtain a dry product containing an amorphous hydrated zinc silicate compound (molar ratio (SiO ₂ /ZnO): 2.22). I got something.

<Evaluation>
The dried products obtained in each Example and Comparative Example were evaluated on the following items. As reference examples, activated carbon (manufactured by Wako Pure Chemical Industries, Ltd., crushed form, 0.2 to 1 mm) and activated clay (manufactured by Wako Pure Chemical Industries, Ltd., main component: montmorillonite) were also evaluated in the same manner.
The evaluation results are summarized in Tables 1 to 3.

<Evaluation items>
1. Amount of amino groups contained in 1 g of dry product The amount of amino groups was determined by quantifying the nitrogen content using the Kjeldahl method. The nitrogen content is determined by thermally decomposing the dried material using sulfuric acid and a decomposing agent (potassium sulfate/copper sulfate mixed powder), converting the nitrogen contained in the dried material into ammonium sulfate, and then adding an aqueous sodium hydroxide solution to this. The ammonia generated was collected in an aqueous boric acid solution and determined by titration.
2. Specific surface area Measured using "BELsorp-max" manufactured by Microtrac Bell Co., Ltd. Specifically, it was measured by a constant volume gas adsorption method using nitrogen gas, and the specific surface area was determined by analysis using the BET multipoint method. In addition, in measuring the specific surface area, vacuum deaeration was performed at 105° C. for 1 hour as a pretreatment of the dried material.
3. Total pore volume Measured using "BELsorb-max" manufactured by Microtrac Bell Co., Ltd. Specifically, it was measured by a constant volume gas adsorption method using nitrogen gas, and the total pore volume was determined from the maximum adsorption amount by a one-point method at the maximum relative pressure. In addition, in measuring the total pore volume, vacuum deaeration was performed at 105° C. for 1 hour as a pretreatment of the dried material.
4. Mesopore volume was measured using "BELsorb-max" manufactured by Microtrac Bell Co., Ltd. Specifically, it was measured by a constant volume gas adsorption method using nitrogen gas, and the mesopore volume (integrated pore volume of pores with a diameter of 1 nm to 100 nm) was determined by pore distribution analysis using the BJH method. . In addition, in measuring the mesopore volume, vacuum deaeration was performed at 105° C. for 1 hour as a pretreatment of the dried material.
5. Content of SiO ₂ Measured by gravimetric method. Specifically, the dried product is evaporated to dryness using hydrochloric acid and perchloric acid, the residue is filtered through a filter paper and thoroughly washed with water, and then the residue is placed in a magnetic crucible together with the filter paper and heated to burn and carbonize. Then, it was ignited at 950° C., and the mass after cooling was measured to determine the SiO ₂ content (% by weight).
Note that the above molar ratio is a value obtained by dividing the value obtained by converting the content of SiO ₂ into molar terms by the value obtained by converting the content of M _m O _n into molar terms. Here, the content of M _m O _n was determined by a chelate titration method. Specifically, hydrochloric acid is added to the dried material and dissolved by heating, the residue is filtered through filter paper and thoroughly washed with water, the washing liquid and filtrate are combined, this is diluted with ion-exchanged water, and then chelate titration is performed. The metal salt concentration was measured using a method to determine the M _m O _n content.
6. Gas adsorption capacity (adsorption rate)
(1) Acetaldehyde A 1L Tedra bag (GL Science, "Smart Bag PA") containing 30mg of dry matter was filled with 100ppm acetaldehyde gas (test gas) and left for 1, 60, and 120 minutes for adsorption tests. After performing this, 1 ml of the residual test gas in the Tedra bag was introduced into a Gachromatograph (manufactured by Shimadzu Corporation, "GC-2014") to measure the concentration of the residual test gas. The adsorption rate was calculated using the following formula (1).
Adsorption rate = {(Test gas concentration before adsorption test−Test gas concentration after adsorption test)/Test gas concentration before adsorption test}×100...Formula (1)
Note that the measurement conditions using the gas chromatograph are as follows.
・Carrier gas: N ₂ , 50ml/min
・Detector: FID detector ・Column oven temperature: 130℃
・Sample vaporization chamber temperature: 200℃
・Detector temperature: 200℃
・Column: Using SHIMADZU GlassColum FFAP+H3PO4 (2) Trimethylamine A 1L Tedra bag containing 30mg of dry matter was filled with 200ppm trimethylamine gas (test gas) and left for 1, 60, and 120 minutes to conduct an adsorption test. Thereafter, 1 ml of the residual test gas in the Tedra bag was introduced into a gas chromatograph to measure the concentration of the residual test gas, and the adsorption rate was calculated using the above formula (1).
Note that the measurement conditions using the gas chromatograph are as follows.
・Carrier gas: N ₂ , 50ml/min
・Detector: FID detector ・Column oven temperature: 80℃
・Sample vaporization chamber temperature: 130℃
・Detector temperature: 130℃
Karam: SHIMADZU GLASSCOLUM DIGLYCEROL + TETRAEHYLENENENTAMINE + KOH (3) 1L Tedora bag containing 30 mg of ammonia dramatic, full of 200 ppm ammonia gas (applied gas). , 60, 120 minutes left and performed an adsorption test Thereafter, the concentration of the residual test gas in the Tedra bag was measured using a gas detection tube (manufactured by Gastech, "3La"), and the adsorption rate was calculated using the above formula (1).
(4) Acetic acid A 1L Tedra bag containing 30 mg of dry matter was filled with 100 ppm of acetic acid gas (test gas), and left to stand for 1, 60, and 120 minutes to conduct an adsorption test. 1 ml of the gas was introduced into the gas chromatograph, the residual test gas concentration was measured, and the adsorption rate was calculated using the above formula (1).
Note that the measurement conditions using the gas chromatograph are as follows.
・Carrier gas: _N2 , 60ml/min
・Detector: FID detector ・Column oven temperature: 150℃
・Sample vaporization chamber temperature: 200℃
・Detector temperature: 200℃
・Column: Use SHIMADZU GlassColum FFAP+H3PO4 (5) Hydrogen sulfide A 1L Tedra bag containing 30mg of dry matter was filled with 100ppm hydrogen sulfide gas (test gas), and left to stand for 1, 60, and 120 minutes to conduct an adsorption test. After that, 1 ml of the residual test gas in the Tedra bag was introduced into the gas chromatograph, the concentration of the residual test gas was measured, and the adsorption rate was calculated using the above formula (1).
Note that the measurement conditions using the gas chromatograph are as follows.
・Carrier gas: N ₂ , 50ml/min
・Detector: FPD detector ・Column oven temperature: 60℃
・Sample vaporization chamber temperature: 130℃
・Detector temperature: 130℃
・Column: Use SHIMADZU GlassColumbeββ'-OxyDiPropionNitril

It can be said that as the amount of amino groups increases, the adsorption ability for acetaldehyde gas tends to increase. Furthermore, it can be said that the closer the value of mesopore volume/total pore volume is to 1, the higher the adsorption ability for acetaldehyde gas tends to be.

In each example, the adsorption ability for various gases can be confirmed. It can be said that by using a metal silicate as a carrier, the adsorption ability for various gases (desired gases) can be enhanced.

<FE-SEM observation>
Example 3, Comparative Example 3, Example 4, and Comparative Example 4 were observed using a field emission scanning electron microscope (JSM-7600F manufactured by JEOL Ltd.) (2000x magnification).
The observation results of Example 3 are shown in FIG. 1A, the observation results of Comparative Example 3 are shown in FIG. 2, the observation results of Example 4 are shown in FIG. 3A, and the observation results of Comparative Example 4 are shown in FIG.

From FIG. 1A and FIG. 3A, it can be confirmed that spherical particles are obtained in Examples 3 and 4 in which spray drying was performed.

<Angle of repose>
For Example 3, Comparative Example 3, Example 4, and Comparative Example 4, the angle of repose measurement was carried out by the injection method using a hanging/electromagnetic vibration type angle of repose measuring device (manufactured by Tsutsui Rikagaku Kiki Co., Ltd., "TYPE AOR-14"). The angle was measured.
The measurement results are summarized in Table 4.

<Pore distribution measurement>
Examples 3 and 4 were measured using "BELsorb-max" manufactured by Microtrac Bell Co., Ltd. Specifically, it was measured by a constant volume gas adsorption method using nitrogen gas, and the differential pore volume distribution (dV/dD) was determined by analysis using the BJH method.
The measurement results of Example 3 are shown in FIG. 1B, and the measurement results of Example 4 are shown in FIG. 3B.

It can be confirmed that all of them have a peak within the range of pore diameters of 10 nm or less.

The gas adsorbent of the present invention can be used as a deodorant or deodorizer for any appropriate purpose. For example, it can be used for air purifier filters, interior materials for automobiles, wallpaper, sheet products, various fibers, paints, and resin molded products.

Claims (12)

It is composed of a porous body containing a metal silicate, and has an amino group supported on the porous body,
The amount of the amino group contained in 1 g is 3 mmol or less,
The content of SiO ₂ is 35% by weight or more and 75% by weight or less,
The BET specific surface area is 200 m ² /g or more, and the mesopore volume is 0.35 cm ³ /g or more .
Gas adsorbent. The gas adsorbent according to claim 1 , wherein the porous body contains an amorphous metal silicate. The gas adsorbent according to claim 1 or 2 , wherein the metal silicate contains magnesium silicate. The gas adsorbent according to any one of claims 1 to 3 , wherein the amount of the amino group contained in 1 g is 0.1 mmol or more. The gas adsorbent according to any one of claims 1 to 4 , wherein the amount of amino groups contained in 1 g is 2 mmol or less. The gas adsorbent according to any one of claims 1 to 5 , having a total pore volume of 0.4 cm ³ /g or more. The gas adsorbent according to any one of claims 1 to 6 , wherein the ratio of mesopore volume to total pore volume (mesopore volume/total pore volume) is 0.75 or more. The gas adsorbent according to any one of claims 1 to 7 , which has at least one peak in a pore diameter range of 10 nm or less in pore distribution according to the BJH method. obtaining a first liquid containing a reaction product of a precursor of the porous body containing the metal silicate and an amino group-containing compound, and
drying the first liquid;
A method for producing a gas adsorbent according to any one of claims 1 to 8 . The manufacturing method according to claim 9 , wherein the first liquid is dried by a spray drying method. Contacting the gas adsorbent according to any one of claims 1 to 8 with a gas,
Gas adsorption method. A deodorizing product comprising the gas adsorbent according to any one of claims 1 to 8 .

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