JP2003181282A - Production method of adsorbing material or adsorbing film, adsorbing material or adsorbing film obtained and application thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a production method of adsorbing material or adsorbing film which has large specific surface area, uniform mesopore size and small hysteresis in adsorption/desorption of water at relative humidity 10-50% and to provide the adsorbing material or adsorbing film and application thereof. <P>SOLUTION: This production method of adsorbing material features that porous silica is subjected to humidification treatment under the environment of temperature 20-80°C and relative humidity 40-90% for 1-10 hr. Further, this production method of adsorbing film features that the adsorbing material is deposited on a substrate surface together with a binder. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a sensor, an adsorber, etc.
In particular, the present invention relates to a method for producing an adsorbent or an adsorbent film applicable to an adsorbent heat pump, the adsorbent or adsorbent film obtained, and uses thereof.

[0002]

BACKGROUND OF THE INVENTION Conventionally, silica gel has been used as an adsorbent for adsorbing or desorbing adsorbed water in the atmosphere.
Activated carbon is known. However, these adsorbents are relatively easy to adsorb and desorb because the voids are non-uniform and the pore volume is not so large, but the adsorbed amount per unit weight could not be increased. . On the other hand, zeolite is a material with uniform pores, but since the pores are small and there are acid points on the surface of the pores, the heat of adsorption of water is large. Therefore, in order to desorb the adsorbed water, , High temperature, high calorie required.

By the way, in recent years, a porous material having uniform mesopores synthesized by utilizing cooperative organization (self-assembly) by interaction between an organic compound and an inorganic compound is a conventional silica gel. It has attracted attention because it has a larger pore volume and a larger surface area than porous materials such as zeolite and zeolite. As a method for producing a porous material having uniform mesopores by utilizing cooperative organization due to interaction between an organic compound and an inorganic compound, for example, WO91 / 1139 is used.
No. 0 describes a method for producing by hydrothermal synthesis using a silica gel and a surfactant in a sealed heat-resistant container. In addition, Bull. Chem. So
c. Jp. Magazine, Vol. 63, page 988, describes a method for producing a porous material by ion exchange between kanemite, which is a kind of layered silicate, and a surfactant.

This porous material is generally called mesoporous silica, and is characterized by having uniform mesopores of regular arrangement such as lamella, hexagonal and cubic, and has a large pore volume. Furthermore, since it has a large number of hydroxyl groups on the surface of the pore walls, it has a large amount of water adsorbed, and its application as a water adsorbent, application to separation adsorbents, sensors, catalyst carriers, and fuel cells are being studied. . However, there is a problem that a high specific surface area cannot be maintained when the regular arrangement of the mesoporous silica is lost.

Further, silica gel does not have a regular array,
There is no known one having such a high specific surface area and a large pore volume. There are some known applications of this porous material having mesopores to an adsorbent. For example, Japanese Unexamined Patent Publication No. 09-178292 and Japanese Unexamined Patent Publication No. 09-
JP-A-227249 and JP-A-09-264633 describe application to various adsorbents for adsorption heat pumps, humidity adjustment, and solvent recovery. The bulk density of the porous materials (powder) obtained in the examples of these publications is high, but the pore volume is 0.4 because the mesopores have no regularity.
It did not exceed ml / g, and it cannot be said that the amount of water adsorbed was particularly large. In addition, JP-A-11-114
In Japanese Patent No. 410, an attempt is made to impregnate such a mesoporous material with a depressurizing agent that lowers the vapor pressure of the liquid to lower the saturated vapor pressure of the liquid and improve the adsorption performance. I couldn't say.

Further, in order to apply a porous material having mesopores to a water-based adsorption heat pump, it is also described in No. 211 of 1998, an information magazine "Management of Asu" (GRC issue No. 211). As described above, it is of course necessary that the total amount of water adsorbed is large, but it is an essential condition that the amount of water absorbed is large when the relative humidity is 10 to 50%. Generally, mesoporous silica typified by MCM-41 having a regular array of uniform mesopores forms an organic-inorganic composite by utilizing cooperative organization by interaction between an organic compound and an inorganic compound. It is produced by further forming and removing organic substances from the composite by calcination. Since the skeleton of the mesoporous silica thus obtained is amorphous, the surface of silica exhibits the same properties as silica gel. If the firing temperature of the above-mentioned organic-inorganic composite is in the range of 100 to 170 ° C., the silica surface of the obtained mesoporous silica has a property of desorbing adsorbed water, but if the firing temperature is further increased, dehydration condensation of surface silanol groups will occur. A reaction occurs and the ability to desorb adsorbed water decreases. Therefore, in order to use the calcined mesoporous silica as an adsorbent, it is necessary to restore the surface silanol groups on which the dehydration condensation reaction has occurred to silanol groups. At this time, it should be noted that heat treatment in a steam atmosphere promotes surface diffusion of silicate ions. In particular, when the concentration of water vapor increases in the pores, hydrothermal reaction occurs in the pores, and the surface area of the pores, the pore structure, etc. change. Therefore,
In the case of treatment with steam, it is necessary to prevent the surface condition of the pores from changing.

Further, in Japanese Patent Laid-Open No. 2001-149735, for dehumidification or heat exchange, porous silica having mesopores prepared in a solution to which an acid is added is subjected to a hydrophilizing treatment in steam to remove moisture or heat. A method of manufacturing a functional device is disclosed. As described above, the hydrophilization treatment is effective for increasing the silanol groups on the silica surface to serve as an adsorbent, but the steam collapse with boiling water causes the structural collapse of the pores and reduces the adsorption amount. Therefore, it is not preferable.

A porous silica film prepared by spin coating or the like from a solution to which an acid is added easily forms a regular structure if it is a thin film, but if the film thickness increases, the evaporation of the solvent will not be uniform. , It becomes difficult to form a regular structure. That is, in order to manufacture an adsorbent by this method, it is necessary to form thin films in layers, which is not preferable as an industrial manufacturing method.

On the other hand, in consideration of use in a heat pump, when the adsorbent has mesopores having a pore diameter of more than 5 nm, water hardly adsorbs at a relative humidity of 50% or less, and the adsorbent is When the water adsorption isotherm is measured, the difference (hysteresis) between the adsorption isotherm on the desorption side and the adsorption isotherm on the adsorption side becomes large. Therefore, it is also important that the adsorbent is mesoporous silica having uniform pores whose pore diameter does not exceed 5 nm.

For the above reasons, at present, the most suitable adsorbent is silica gel (A type) as described in Chemical Engineering Papers, Vol. 19, No. 6 (1993) 1165. Is. However, in this silica gel, even when the relative humidity is as low as 10 to 50%, the adsorption of water is large relative to the total adsorption amount, but the total pore volume is not so large.

Therefore, the amount of water adsorbed is larger than that of conventional silica gel, and particularly the amount of water adsorbed is large at a relative humidity of 10% to 50%, and an adsorbent which can be industrially prepared is very useful as an adsorption heat pump material. Is desired.

[0012]

SUMMARY OF THE INVENTION The present invention is intended to solve the problems associated with the prior art as described above, and is a method for producing an adsorbent or an adsorbent film which can be applied to a sensor, an adsorber or the like, particularly an adsorption heat pump. And to provide the obtained adsorbent or adsorbent film, and uses thereof. That is, the present invention has a large specific surface area, has mesopores of a uniform size, and further absorbs and desorbs water, especially at a relative humidity of 10%.
A method for producing an adsorbent or an adsorbent film made of porous silica having a small hysteresis in water adsorption / desorption at -50%
Further, it is an object of the present invention to provide the obtained adsorbent or adsorbed film, and uses thereof.

[0013]

SUMMARY OF THE INVENTION In the method for producing an adsorbent according to the present invention, porous silica is used at a temperature of 20 to 80 ° C. and a relative humidity of 4.
It is characterized in that the humidification treatment is performed for 1 to 10 hours in an atmosphere of 0% to 90%. It is preferable that the specific surface area of the porous silica measured by the nitrogen adsorption method is 800 m ² / g or more, and the average pore diameter of the porous silica measured by the method is 0.5 to 4 nm.

Further, the porous silica is obtained by removing the alkylamines from an organic-inorganic composite composed of polycondensates of alkoxysilanes and micelle-forming alkylamines. And
The alkoxysilanes are represented by the general formula; (ZO) _4-n SiR _n (wherein Z and R represent C _X H _{2X + 1} , X is an integer of 1 to 4, and Z and R are the same. But it can be different,
n is an integer of 0 to 3. It is also preferable that the alkylamines are represented by the general formula; YNH ₂ (wherein Y represents C _m H _{2m + 1} , and m represents an integer of 6 to 20).

The organic-inorganic composite is obtained by adding the alkoxysilanes to a mixed solution of the alkylamines and water, and then stirring and mixing the mixture at a temperature of 25 to 70 ° C. for 1 to 150 hours. Is preferred. It is preferable that the alkylamines are octylamines and the alkoxysilanes are tetraalkoxysilanes.

The adsorbent according to the present invention is characterized by being obtained by the method for producing the adsorbent. The specific surface area of the adsorbent measured by the nitrogen adsorption method is 800 m ² /
It is preferable that it is g or more and the average pore diameter of the adsorbent measured by the method is 0.5 to 4 nm.

The method for producing an adsorbent film according to the present invention is characterized in that the adsorbent is supported on the surface of a base material together with a binder. The adsorption film according to the present invention is characterized by being obtained by the method for producing an adsorption film. The specific surface area of the adsorption film measured by the nitrogen adsorption method is 800 m ² /
It is preferable that it is g or more and the average pore diameter of the adsorption film measured by the method is 0.5 to 4 nm.

The adsorbent according to the present invention is characterized in that the adsorbent is used in an adsorption heat pump. The adsorption film according to the present invention is characterized by using the adsorption film in an adsorption heat pump.

[0019]

DETAILED DESCRIPTION OF THE INVENTION The method for producing an adsorbent or an adsorbent film according to the present invention, the adsorbent or adsorbent film thus obtained, and their uses will be specifically described. First, a method for manufacturing an adsorbent according to the present invention will be described. [Method for producing adsorbent] In the method for producing an adsorbent according to the present invention, the porous silica described below has a temperature of 20 to 80 ° C, preferably 20 to 60 ° C, more preferably 20 to 50 ° C.
And in a relative humidity of 40% to 90%, preferably 40 to 75%, more preferably 40 to 60%, for 1 to 10 hours, preferably 1 to 8 hours,
More preferably, it is desirable to perform the humidification treatment for 2 to 5 hours.

Since this porous silica is obtained through a firing step as described later, the surface of the porous silica is
Dehydration condensation of silanol groups is occurring. Therefore, in order to use the porous silica as an adsorbent or the like, it is necessary to restore the original silanol group. Humidification is effective as a method for treating the silica surface, but treatment in hot steam is not preferable because it causes structural collapse of pores. In particular, in the case of porous silica having a large specific surface area, such treatment in hot steam is not preferable because the specific surface area is significantly decreased due to the structural collapse of the pores. In the present invention, by subjecting the porous silica to a humidification treatment under the above-mentioned conditions, it is possible to return it to a silanol group without causing structural collapse of the pores.

By subjecting the porous silica to the humidification treatment (surface treatment) in this manner, the specific surface area is almost the same as before treatment, and since the porous silica has many silanol groups on the surface, the relative humidity is increased. At 10% to 50%, it is possible to obtain an adsorbent having a small hysteresis in water adsorption / desorption. [Adsorbent] The adsorbent according to the present invention is obtained by the above manufacturing method. Such adsorbents have uniform pores,
Specific surface area measured by a nitrogen adsorption method 800 m ² / g or more, preferably 800~1800m ² / g, more preferably from 900~1500m ² / g, and an average pore size measured by nitrogen adsorption method 0. 5-4 nm, preferably 0.5-3.5 nm, more preferably 1-3.
It is preferably 5 nm. The specific surface area and average pore diameter of the adsorbent of the present invention may be any combination within the above range.

The adsorbent of the present invention has a relative humidity of 1 when the specific surface area and the average pore diameter of the adsorbent are within the above ranges.
At 0% to 50%, the hysteresis due to adsorption and desorption of water is small, and it has very excellent performance as an adsorbent. Further, in the present invention, the adsorbent film according to the present invention can be manufactured using this adsorbent. Next, a method of manufacturing the adsorption film according to the present invention will be described.

[ Production Method of Adsorption Film] The production method of the adsorption film according to the present invention is carried out by adding a binder to the above-mentioned adsorbent and further coating it on a substrate. Examples of the method for applying to the substrate include general methods such as a spraying method, a spin coating method, a casting method, and a dip coating method. Further, the adsorbent, which has been subjected to the humidification treatment as described above, is applied onto the substrate, and then 100 ° C. or lower, preferably 60 ° C.
It is desirable to dry in a temperature range of -100 ° C for 30-300 minutes, preferably 30-180 minutes. As described above, the same adsorption performance as that of the adsorbent of the present invention can be obtained by using the humidified adsorbent and drying it under the above drying conditions.

As the above-mentioned substrate, any substrate can be used as long as it is generally used. Examples include metals such as copper and aluminum, alloys such as stainless steel, ceramics, metal oxides, and glass. Further, the shape of the base material may be any of a honeycomb shape, a cylindrical shape, a plate shape, a dish shape, a complicated shape with fins, or the like. As the binder when applied to the substrate, either organic or inorganic binders can be used. For example, as an organic binder, vinyl acetate, methyl cellulose,
Polyvinyl alcohol, epoxy resin, polyalkylene oxide, polyalkylene glycol, and the like can be used. As the inorganic binder, silica-based, alumina-based, cement or the like can be used. The amount of the binder added is not particularly limited, but is usually 0.5 to 20% by weight, preferably 0.5 to 15% by weight, based on 100% by weight of the porous silica.
It is preferable to add a binder within the above range, because the base material and the adsorption film are firmly adhered to each other and the water absorption amount of the adsorption film does not decrease significantly.

[Adsorption Film] The adsorption film according to the present invention obtained by the above manufacturing method is characterized in that the adsorbent is formed as a film on a base material. The thickness of the adsorption film is not particularly limited as long as the adsorption performance can be effectively exhibited, and is usually about 1 μm to 2 mm. Also,
The adsorbent film of the present invention is formed by using the adsorbent described above, and the specific surface area and average pore diameter of the adsorbent as a raw material hardly change in the obtained adsorbent film.

Such an adsorption membrane has uniform pores,
Specific surface area measured by a nitrogen adsorption method 800 m ² / g or more, preferably 800~1800m ² / g, more preferably from 900~1500m ² / g, and an average pore size measured by nitrogen adsorption method 0. 5-4 nm, preferably 0.5-3.5 nm, more preferably 1-3.
It is preferably 5 nm. The specific surface area and the average pore diameter of the adsorption film of the present invention may be any combination within the above range.

The adsorbent membrane of the present invention uses the adsorbent produced by subjecting porous silica to a humidification treatment (surface treatment), and the specific surface area and average pore diameter of the adsorbent membrane are within the above ranges. As a result, the hysteresis due to adsorption and desorption of water is small at a relative humidity of 10% to 50%, and it has a very excellent performance as an adsorption film. As described above, the adsorbent of the present invention,
Alternatively, porous silica is used for producing an adsorption film. The porous silica will be described below.

Porous Silica The porous silica used in the present invention has uniform pores and has a specific surface area of 800 m ² / measured by the nitrogen adsorption method.
g or more, preferably 800 to 1800 m ² / g, more preferably 900 to 1500 m ² / g, and having an average pore diameter measured by a nitrogen adsorption method of 0.5 to 4 nm,
Preferably 0.5-3.5 nm, more preferably 1-
It is preferably 3.5 nm. The specific surface area and average pore diameter of the adsorbent of the present invention may be any combination within the above range. With such a porous silica,
The adsorbent and the adsorbent film obtained by performing the above-mentioned humidification treatment (surface treatment) have a small hysteresis when adsorbing and desorbing water, and have excellent performance as an adsorbent.

Such a porous silica is manufactured as follows. First, the general formula: YNH ₂ (wherein Y is C _m H
_{It is represented by 2m + 1} and represents an integer of m = 6 to 20. ) The alkylamines represented by) and water are mixed and stirred to prepare a mixed solution. Examples of the alkylamines include hexylamine, octylamine, decylamine, dodecylamine, tetradecylamine, hexadecylamine, octadecylamine and the like, and octylamine is preferably used. In the present invention, the alkylamines may be used alone or in combination of two or more. The amount of water added to the mixed solution is 30 to 80 mol, preferably 3 to 1 mol of alkylamines.
It is desirable to use it in an amount of 5 to 60 mol. Within this range, the mixed solution can be easily stirred, and the alkylamines can form micelles.

When the mixed solution is prepared in the above range, the pH of the mixed solution is preferably in the range of 9 to 13, and a pH adjuster (for example, hydrochloric acid) can be added to the mixed solution. The above-mentioned alkylamines and water may be mixed and stirred as long as the mixed solution becomes uniform, and usually 10 minutes to 1 minute.
Do about an hour. At this time, the temperature of the mixed solution is 15 to 50.
It is desirable that the temperature is 0 ° C, preferably 20 ° C to 40 ° C.

Next, the general formula: (ZO) _4-n SiR _n (wherein Z and R represent C _X H _{2X + 1} , X is an integer of 1 to 4, and Z and R are the same. Or they may be different, n =
Indicates an integer of 0 to 3. ) Alkoxysilanes represented by the formula (1) are added to the above mixed solution and mixed and stirred. The mixing ratio of the alkoxysilanes and the alkylamines in the mixed solution is preferably in the range of 0.05 to 1.5 mol of the alkylamines with respect to 1 mol of the alkoxysilanes. The alkylamines also have a role of adjusting pH, and there is no problem even if added in a large amount, but it is not preferable from the viewpoint of manufacturing cost. The alkylamines are used so that the pH of the mixed solution after adding the alkoxysilanes is 9 or more. When the alkylamines are used in such a range, the alkylamines and the alkoxysilanes form a uniform complex, and then, when the alkylamines are removed, pores having mesopores of uniform size are formed. Quality silica can be obtained.

Examples of the alkoxysilanes include tetraalkoxysilane, trialkoxysilane and dialkoxysilane, and it is preferable to use tetraalkoxysilane. Examples of such tetraalkoxysilane include tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, and tetrabutylsilane. In particular, it is preferable to use tetraethoxysilane. Depending on the case, other metal alkoxides may coexist, but it is preferable to use the porous silica obtained in an amount of 80 to 100% by weight based on 100% by weight of porous silica. .

If desired, the alkoxysilanes may be diluted with a solvent before use. Such a solvent is usually used in an amount of 5 mol per 1 mol of alkoxysilanes.
It is preferably used in an amount of -20 mol. Examples of such a solvent include primary alcohols such as methanol, ethanol and 1-propanol; secondary alcohols such as 2-propanol and 2-butanol; tertiary alcohols such as tertiary butyl alcohol; acetone and acetonitrile. The above solvents may be used alone or in combination of two or more. By diluting the alkoxysilanes with a solvent, rapid hydrolysis of the alkoxysilanes can be controlled.

To add the above-mentioned alkoxysilanes to the mixed solution, specifically, the alkoxysilanes diluted with a solvent are added to the mixed solution of alkylamine and water. As a result, a hydrolysis reaction of the alkoxysilanes occurs, a precipitate is generated, and after that, the structure formation of the organic-inorganic composite is completed by stirring and mixing. At this time,
The method for adding the alkoxysilanes diluted with a solvent is not particularly limited.

The stirring and mixing performed after adding the alkoxysilanes to the mixed solution is continued at a temperature of 25 to 70 ° C., preferably 25 to 50 ° C. for 1 to 150 hours, preferably 1 to 72 hours. It is desirable to do so. By this stirring and mixing, the organic-inorganic composite of the polycondensate of silica and the alkylamines is formed with a more regular structure.

The solution after stirring and mixing contains the organic-inorganic composite of the polycondensate of silica and the alkylamines as described above. Such a solution is filtered to remove the alkylamines that did not contribute to the formation of the organic-inorganic composite together with the by-produced alcohol, solvent, and water. In some cases, the filtrate can be washed with an organic solvent such as alcohol or water. Furthermore, when the alkylamines are removed from the produced organic-inorganic composite, porous silica in which the alkylamines are vacant is formed. As a method of removing the alkylamines from such an organic-inorganic composite, there is a method of firing the organic-inorganic composite, a method of extracting the alkylamines from the organic-inorganic composite with alcohol or the like. When the organic-inorganic composite is fired, if the temperature is raised while the solvent, water, etc. remain in the composite, the structure of the pores may change, so it is desirable to include a drying step before firing. Further, when extraction is performed, sufficient drying and, if necessary, baking are required to remove the solvent, water, etc. remaining after the extraction. The firing for removing the remaining alcohols and alkylamines also contributes to strengthening the silica skeleton of the porous silica. Usually, this baking is performed at 300 ° C. to 800 ° C. for 1 to 10 hours. In this way, the porous silica used in the present invention is prepared.

[ Use of Adsorbent and Adsorption Film ] The adsorbent and the adsorption film according to the present invention have mesopores having a large specific surface area and a uniform size as described above, and a relative humidity of 10%. Since it has a small hysteresis in water adsorption and desorption at -50% and has an extremely excellent performance as an adsorbent material, it can be used in sensors and adsorbers, and is particularly preferably used in adsorption heat pumps.

[0038]

According to the present invention, the mesopores having a large specific surface area and a uniform size are provided, and the relative humidity is 1
It is possible to provide a method for producing an adsorbent or an adsorbent film having a small hysteresis of 0 to 50% in water adsorption and desorption, an adsorbent or an adsorbent film, and uses thereof.

[0039]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. The water adsorption isotherms used in the following examples and comparative examples were prepared as follows. Preparation of water adsorption isotherm Put the sample to be measured in a sample tube with a volume of about 5 ml, degas it until the inside of the system becomes 0.13 Pa or less, and then measure the automatic vapor adsorption amount (BELSORP18 PLUS; Nippon Bell Co., Ltd.). Made)
Water vapor adsorption test was conducted at a temperature of 25 ° C. At each relative humidity (P / Ps), the water absorption rate on the adsorption side and the water absorption rate on the desorption side were measured, and a water adsorption isotherm on the adsorption side and a water adsorption isotherm on the desorption side were created.

[0040]

Example 1 Octylamine (C ₈ H ₁₇ NH ₂ ) 10.0
g and 50.6 g of water are mixed and stirred at 25 ° C. for 60 minutes,
A homogeneous solution was obtained. Tetraethoxysilane (Si (OC
16.2 g of ₂ H ₅ ) ₄ ) was diluted with 23.4 g of ethanol, and the diluted solution was poured into the above mixed solution at 25 ° C., and further stirred and mixed at 35 ° C. for 18 hours. After stirring and mixing, the solution in which a white precipitate of the organic-inorganic composite had formed was filtered with a suction filter, and the precipitate was washed with water and dried. Firing was carried out at 600 ° C. for 3 hours in order to remove octylamine from the obtained organic-inorganic composite. Powder after firing is X
There was a peak representing a hexagonal structure by the line diffraction method. As a result of measuring the specific surface area and pore distribution of this porous silica by a nitrogen adsorption method, the specific surface area was 1250 m ² /
and the average pore diameter was 2.8 nm.

This porous silica was treated at 30 ° C. and a relative humidity of 50.
% Atmosphere for 4 hours for humidification. The obtained adsorbent had a peak showing a hexagonal structure by X-ray diffractometry and had a specific surface area of 1240 m ² /
g, the average pore diameter was 2.8 nm, and almost no change in the pore structure due to the treatment was observed. Further, a water adsorption isotherm of this adsorbent was prepared according to the method described above. The results are shown in Figure 1. As a result, the adsorbent obtained had a water adsorption amount of 0.65 at a relative humidity (P / Ps) of 90%.
It was found that the adsorption isotherm on the adsorption side and the adsorption isotherm on the desorption side did not significantly differ and the hysteresis was small at a relative humidity of 10% to 50%.

[0042]

[Example 2] In Example 1, the octylamine was removed by ethanol extraction, and the porous silica after extraction was treated with 300
Porous silica was prepared in the same manner except that it was calcined at 3 ° C. for 3 hours. The powder after firing had a peak representing a hexagonal structure by X-ray diffractometry. As a result of measuring the specific surface area and pore distribution of this porous silica by a nitrogen adsorption method, the specific surface area was 1180 m ² / g and the average pore diameter was 2.9 nm.

This porous silica was treated at 30 ° C. and a relative humidity of 50.
% Atmosphere for 4 hours for humidification. The obtained adsorbent had a peak showing a hexagonal structure by an X-ray diffraction method, and had a specific surface area of 1180 m ² /
g, the average pore diameter was 2.9 nm, and there was almost no change in the pore structure due to the treatment. Further, a water adsorption isotherm of this adsorbent was prepared according to the method described above. As a result, the obtained adsorbent has an amount of adsorbing water of 0.64 g / g at a relative humidity (P / Ps) of 90%.
It was found that there was no significant difference between the adsorption isotherm on the adsorption side and the adsorption isotherm on the desorption side at relative humidity of 10% to 50%, and the hysteresis was small.

[0044]

[Comparative Example 1] Porous silica was prepared in the same manner as in Example 1, and no humidification treatment was performed after firing. The water adsorption isotherm of this porous silica was prepared according to the method described above. The results are shown in Figure 2. As a result, the obtained porous silica has an amount of adsorbing water of 0.70 g / g at a relative humidity (P / Ps) of 90%, and is adsorbed and desorbed at a relative humidity of 10% to 50%. A large hysteresis was observed in the adsorption isotherm of.

[0045]

[Comparative Example 2] Porous silica was produced in the same manner as in Example 1, and the moistening treatment after firing was performed for 4 hours in an atmosphere of 85 ° C and 95% relative humidity. The adsorbent after the humidification treatment had a peak showing a hexagonal structure by the X-ray diffraction method.
It is weaker than before treatment and has a specific surface area of 1060m.
² / g, which is 15 compared with 1250 m ² / g before treatment.
% Had been reduced.

[0046]

Example 3 2.0 g of the adsorbent produced by the same operation as in Example 1 was dispersed in 44.0 g of water in which 0.1 g of methyl cellulose was dissolved. A substrate made of glass fibers formed in a honeycomb shape was immersed in the stirred slurry-like solution. Two minutes after soaking the substrate, the substrate was removed from the solution and dried at 80 ° C. for 60 minutes. Do this operation 2
This was repeated to obtain an adsorption film in which the supported amount of porous silica was 95% by weight based on 100% by weight of the substrate. The specific surface area of the obtained adsorption film was 1160 m ² / g, and the average pore diameter was 2.8 nm. The water adsorption isotherm of this adsorption film was prepared according to the method described above. As a result, the amount of water adsorbed at 90% relative humidity (P / Ps) was 0.62 g / g, and the adsorption isotherm on the adsorption side and the adsorption isotherm on the desorption side were observed at 10% to 50% relative humidity. It was found that there was no big difference and the hysteresis was small.

[Brief description of drawings]

FIG. 1 is a diagram showing water adsorption isotherms of the adsorbent obtained in Example 1.

FIG. 2 is a view showing a water adsorption isotherm of the porous silica obtained in Comparative Example 1.

Continued front page    (72) Inventor Yoshito Kurano             580-32 Nagaura, Sodegaura-shi, Chiba Mitsui Chemicals, Inc.             Inside the company (72) Inventor Kazuo Takamura             580-32 Nagaura, Sodegaura-shi, Chiba Mitsui Chemicals, Inc.             Inside the company (72) Inventor Shunsuke Oike             580-32 Nagaura, Sodegaura-shi, Chiba Mitsui Chemicals, Inc.             Inside the company F-term (reference) 4G066 AA14D AA22B AA71C AB13D                       AB18A AC02C BA03 BA07                       BA16 BA23 BA26 CA43 DA03                       FA03 FA12 FA22 FA33 FA34

Claims (12)

[Claims] 1. Porous silica at a temperature of 20 to 80 ° C.
And, in an atmosphere with relative humidity of 40% to 90%,
A method for producing an adsorbent, which comprises performing a humidification treatment for 1 to 10 hours. 2. The specific surface area of the porous silica measured by the nitrogen adsorption method is 800 m ² / g or more, and the average pore diameter measured by the method is 0.5 to 4 nm. The method for manufacturing an adsorbent according to claim 1. 3. The porous silica obtained by removing the alkylamines from an organic-inorganic composite comprising polycondensates of alkoxysilanes and alkylamines forming micelles. Wherein the alkoxysilanes are represented by the general formula; (ZO) _4-n SiR _n (wherein Z and R represent C _X H _{2X + 1} , X is an integer of 1 to 4, and Z and R may be the same or different,
n is an integer of 0 to 3. ) And the alkylamines are of the general formula: YNH ₂ (wherein Y represents C _m H _{2m + 1} and m is an integer of 6 to 20). Item 3. A method for producing an adsorbent according to item 1 or 2. 4. The organic-inorganic composite is obtained by adding the alkoxysilanes to a mixed solution of the alkylamines and water, and then stirring and mixing the mixture at a temperature of 25 to 70 ° C. for 1 to 150 hours. The method for producing an adsorbent according to claim 3, which is the obtained organic-inorganic composite. 5. The method for producing an adsorbent according to claim 3, wherein the alkylamines are octylamines and the alkoxysilanes are tetraalkoxysilanes. 6. An adsorbent obtained by the method for producing an adsorbent according to claim 1. 7. The specific surface area of the adsorbent measured by the nitrogen adsorption method is 800 m ² / g or more, and the average pore diameter measured by the method is 0.5 to 4 nm. The adsorbent according to claim 6. 8. A method for producing an adsorption film, which comprises supporting the adsorbent according to claim 6 or 7 together with a binder on the surface of a substrate. 9. An adsorption film obtained by the method for producing an adsorption film according to claim 8. 10. The specific surface area of the adsorption film measured by a nitrogen adsorption method is 800 m ² / g or more, and the average pore diameter measured by the method is 0.5 to 4 nm. The adsorption film according to claim 9. 11. An adsorbent characterized by using the adsorbent according to claim 6 or 7 in an adsorption heat pump. 12. The adsorption film according to claim 9 or 10,
An adsorption film characterized by being used in an adsorption heat pump.