JPH11253797A - Adsorbent, air cleaning filter and preparation of adsorbent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To highly efficiently remove lower aldehydes existing in a gas phase by making a surface acidic base of an active carbon at a specified value or lower. SOLUTION: It is necessary for an active carbon used for this adsorbent or an air cleaning filter to incorporate an active carbon wherein at least one compd. selected from the group consisting of polyethyleneimine, m-anisidine and p-anisidine is carried. Amt. of such an amine compd. Is pref. 5-20 wt.% to the active carbon. In addition, it is necessary for the active carbon used for the adsorbent or the air cleaving filter to have at most 0.3 meq/g surface acidic base after carrying the amine compd. When the surface acidic base is larger than 0.3 meq/g, even if amt. of carried amine compd. is equal, vol. of adsorption of lower aldehyde is decreased. When the surface acidic base is at most 0.3 meq, the vol. of adsorption does not change remarkably and high level of the vol. of adsorption can be kept.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lower aldehyde adsorbent, an air purification filter, and a method for producing an adsorbent, which are present in a gaseous phase such as a living space or a vehicle interior. Specifically, for example, an adsorbent, an air purification filter, and an adsorbent capable of efficiently removing lower aldehydes present in the gas phase such as formaldehyde generated from furniture, new building materials, etc., acetaldehyde contained in tobacco smoke, automobile exhaust gas, and the like. The present invention relates to a method for manufacturing a material.

[0002]

2. Description of the Related Art For removal of lower aldehydes in living space and the like, various types of organic aldehyde compounds having a porous material such as activated carbon carried thereon have been reported and used.

For example, JP-B-60-54095 and JP-A-7-80292 disclose activated carbon carrying aniline and toluidine as amine compounds. These amine compounds react with lower aldehydes. Although active, it is primarily a drama and is not suitable for use in living spaces.

Japanese Unexamined Patent Publication (Kokai) No. 2-115020 discloses a porous material supporting aminobenzoic acid and aminobenzoic acid sodium salt, and these amine compounds have few safety problems. Has a property as an acid, so that the reactivity with lower aldehydes is not so large, and a sufficient removal performance cannot be obtained.In the case of sodium salt, the molecular weight is large, and as a result, the Since the molar amount of the group cannot be increased, there has been a problem that the life of the removing ability is short.

In Japanese Patent Publication No. 62-51651, activated carbon carrying polyethyleneimine is disclosed in Japanese Patent Application Laid-Open No. 5-31.
JP-A-7703 and JP-A-7-328103 disclose activated carbon supporting a low-molecular-weight aliphatic amine. However, according to the findings of the present inventors, low-molecular-weight aliphatic amine is thermally activated on activated carbon. In addition, deactivation due to chemical change over time is likely to occur, and it is difficult to exhibit satisfactory removal performance over a long period of time. In addition, the above-mentioned JP-B-62-5
JP-A-16551 describes the pore diameter and pore volume, but does not control the surface structure so that the supported amine compound works effectively.

Japanese Patent Application Laid-Open No. 4-180834 proposes that an activated carbon surface is oxidized to form a hydroxyl group, and a silicon compound having an amino group is supported by a chemical bond with the hydroxyl group. Such an amino group-containing silicon compound has a low reaction activity with lower aldehydes, and its removal ability is not always satisfactory.

[0007] Further, some air purification filters containing such activated carbon carrying an amine compound have already been proposed. For example, when they are used in an air purifier or the like, only acidic substances such as aldehydes are used. In addition, the ability to remove basic substances is also required. It is known that adsorption by a porous material carrying an acid is effective for this, but using two types of filters for acidic substances and basic substances separately increases the pressure loss and increases the installation space. Difficult in terms of restrictions. Further, when both the amine compound and the acid are supported on the activated carbon-containing sheet by the impregnation method, when two kinds of compounds are mixed and impregnated, or when two kinds of impregnation liquids are overcoated on the same sheet, the ratio of activated carbon is reduced. There is a problem in that the surface area is greatly reduced, or the properties change due to a chemical reaction between the two, and the original activity for each odorous gas is reduced.

As described above, in the conventional activated carbon supporting an amine compound, the surface structure is not controlled so that the supported amine compound works effectively, and the reaction activity with the lower aldehydes is large. At present, even when an amine compound is supported, the supported amine does not work effectively and satisfactory removal performance has not been obtained.

[0009]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above problems, and it is intended to carry an amine compound which is safe and has a substantially large reaction activity with lower aldehydes, and An object of the present invention is to provide an adsorbent for lower aldehydes in a gaseous phase containing activated carbon whose surface structure is controlled so that its activity is effectively utilized, and a method for producing the same.

The present invention also contains the amine compound-supported activated carbon thus obtained, and has the ability to remove basic substances without impairing the excellent removal properties of the activated carbon for lower aldehydes. It is an object of the present invention to provide an air purification filter formed into a pleated shape and a honeycomb shape.

The present inventors have found that various amine compounds have essential reaction activity with lower aldehydes, safety,
As a result of detailed studies from the viewpoint of physicochemical stability when loaded on activated carbon, polyethyleneimine has excellent reaction activity with lower aldehydes and is relatively stable due to the heat of adsorption during loading. It has been found that m-anisidine and p-anisidine have a large adsorption capacity with activated carbon and those capable of exhibiting the maximum adsorption capacity without any safety problems as aromatic amines.

In addition, the present inventors control the surface structure of amine compound-supported activated carbon in order to effectively utilize the excellent reaction activity of the amine compound to lower aldehydes.
In particular, as a result of study focusing on the control of the amount of surface acidic groups, by controlling the amount of surface acidic groups to 0.3 meq / g or less,
It has been found that the adsorption capacity of lower aldehydes can be maintained at a high level. The above-mentioned surface acidic group means a generic term such as a hydroxyl group —OH, a carboxyl group —COOH, an aldehyde group —CHO, and a carbonyl group> C ＝ O that exist on the surface.

Although the reason for this is not clear, the amount of surface acidic groups after carrying the amine compound often reflects the amount of surface acidic groups of the activated carbon on the carrier. It is presumed that the state was different and the amount of amino groups that could react with lower aldehydes changed.

That is, when the amount of acidic groups on the surface of the activated carbon of the carrier is small, the activated carbon surface is hydrophobic and interacts with the hydrocarbon portion of the amine compound molecule, so that the amino group is oriented outward, and the activated carbon is located in the pores of the activated carbon. Reacts easily with physically adsorbed lower aldehydes. Conversely, when the amount of surface acidic groups increases, the activated carbon surface becomes more hydrophilic and interacts with the amino group, which is the hydrophilic portion of the amine compound molecule, so that the reaction activity with the physically adsorbed lower aldehydes is thought to decrease. .

In addition to the control of the amount of surface acidic groups described above, the present inventors have found that the specific surface area measured by the BET method is 800
It has been found that the removal performance of lower aldehydes is more stable when m ² or more.

Further, the inventors of the present invention have proposed using a carrier activated carbon having a surface acidic group content of 0.5 meq / g or less and a specific surface area of 1200 m ² g or more measured by the BET method. It has been found that after carrying the amine compound, an activated carbon having the surface acidic group content and the specific surface area controlled as described above can be obtained.

The present invention has been achieved as a result of further studies based on the above findings.

[0018]

That is, the present invention relates to an adsorbent containing activated carbon carrying at least one member selected from the group consisting of polyethyleneimine, m-anisidine and p-anisidine, Has a surface acidic group content of 0.3
An adsorbent having a meq / g or less is provided.

In a preferred embodiment of the adsorbent of the present invention, the activated carbon has a specific surface area measured by a BET method of 800 m ^2.
/ G or more.

A preferred embodiment of the adsorbent of the present invention is used for removing lower aldehydes.

The present invention also relates to a filter formed into a pleated or honeycomb shape, wherein at least one selected from the group consisting of polyethyleneimine, m-anisidine and p-anisidine is supported; An object of the present invention is to provide an air purification filter containing activated carbon having a surface acidic group content of 0.3 meq / g or less.

In a preferred embodiment of the air purifying filter of the present invention, the activated carbon has a specific surface area measured by a BET method of 800 m ² / g or more.

A preferred embodiment of the air purifying filter of the present invention includes a basic gas-adsorbing sheet.

Further, the present invention provides a method wherein the amount of surface acidic groups is 0.5
At least one member selected from the group consisting of polyethyleneimine, m-anisidine, and p-anisidine is supported on activated carbon having a meq / g or less and a specific surface area of 1200 m ² / g or more measured by a BET method. The present invention provides a method for producing an adsorbent.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION The activated carbon used in the adsorbent or air purification filter of the present invention is polyethyleneimine, m-
It is necessary to contain activated carbon carrying at least one selected from the group consisting of anisidine and p-anisidine. Such an amine compound has excellent reaction activity with lower aldehydes and is relatively stable against heat of adsorption during loading.

The amount of polyethyleneimine, m-anisidine and p-anisidine supported on activated carbon used in the adsorbent or air purification filter of the present invention is 5 to 5% per activated carbon.
-20% by weight is preferred. In the present invention, when the loading amount of the amine compound is large, the surface acidic groups after the loading are small, but the specific surface area is also reduced at the same time.

The activated carbon used in the adsorbent or the air purification filter of the present invention needs to have a surface acidic group content of not more than 0.3 meq / g after carrying the amine compound. This is because when the amount of surface acidic groups is larger than 0.3 meq / g, the adsorption capacity of lower aldehydes is reduced even if the amount of amine compound supported is the same. When the amount of surface acidic groups is 0.3 meq / g or less, the adsorption capacity does not change so much and a high adsorption capacity level can be maintained.

The above-mentioned surface acidic group content is determined by the method reported by Boehm et al. (Angew. Chem. Intern. Ed. Engl., 5, p533, 19).
66). Specifically, 0.5 g of a dry activated carbon sample was immersed in 60 ml of a 0.02 mol / l aqueous solution of sodium hydroxide, shaken at room temperature for 4 hours, and 25 ml of the supernatant was collected to obtain a 0.02 mol / l aqueous solution. Titration is performed with an aqueous hydrochloric acid solution, and the amount of surface acidic groups can be calculated from the alkali consumption determined using a phenolphthalein indicator. The unit of the surface acidic group, meq / g, represents a milliequivalent (1/1000 of an equivalent) of an acid per 1 g of activated carbon sample.

The above-mentioned surface acidic group means a general term such as a hydroxyl group —OH, a carboxyl group —COOH, an aldehyde group —CHO, and a carbonyl group> C O which exist on the surface of activated carbon.

The activated carbon used in the adsorbent or the air purification filter of the present invention needs to have a specific surface area measured by the BET method of at least 800 m ² / g after carrying the amine compound. When the specific surface area is less than 800 m ² / g, the physical adsorption ability of the lower aldehyde decreases, and a satisfactory removal ability cannot be achieved.

The above specific surface area is determined by the BET method by measuring the adsorption isotherm of nitrogen gas at the temperature of liquid nitrogen. To be specific, a soapmatic made by Carlo Elba
After the adsorption isotherm is measured using SSII-80, the adsorption isotherm is determined by calculation using the adsorption amount data in the range of 0.05 to 0.20 in the equilibrium adsorption pressure / saturated vapor pressure.

The method for producing an adsorbent according to the present invention is characterized in that activated carbon having a surface acidic group content of 0.5 meq / g or less and a specific surface area of 1200 m ² / g or more measured by the BET method is added to polyethyleneimine. , M-anisidine, and p-anisidine. By carrying the amine compound on such a carrier activated carbon, an adsorbent having the excellent lower aldehyde removal performance described above can be obtained.

Activated carbon having an amount of surface acidic groups of 0.5 meq / g or less can be used, for example, in a steam activation method.
After activation at ~ 1000 ° C, it is obtained by maintaining the activated carbon temperature in an inert gas atmosphere such as nitrogen until the temperature of the activated carbon becomes 300 ° C or less. To obtain the above-mentioned activated carbon from activated carbon having a surface acidic group content of more than 0.5 meq / g, 60
It is obtained by reheating at 0 to 1200 ° C. in an atmosphere of an inert gas such as nitrogen and maintaining the atmosphere as it is until the activated carbon temperature becomes 300 ° C. or less.

In the present invention, the method of supporting the amine compound on the activated carbon is not particularly limited. For example, the amine compound is dissolved in water or a suitable organic solvent to form a solution having an arbitrary concentration, and the solution is used as a carrier. Immersed in activated carbon,
After application, a method of drying at a predetermined temperature or the like is used. When the adsorbent of the present invention is a molded body such as a honeycomb, a corrugated, a sheet, a felt, a plate, or a urethane foam to which powder is attached, activated carbon is previously molded. After that, the amine compound may be supported, or the amine compound may be supported on activated carbon such as powdery, granular, or fibrous and then molded into a desired shape.

As described above, the adsorbent of the present invention may be activated carbon itself carrying an amine compound, or may be formed by molding. In the case of the former, there are shapes such as powdery, granular, and fibrous, and as the latter, activated carbon is made of honeycomb, corrugated, sheet, felt,
There are, for example, those molded into a plate shape and those obtained by adhering powder to urethane foam. The adsorbent of the present invention includes all of these.

The air purification filter of the present invention needs to be formed in a pleated or honeycomb shape, and preferably contains a basic gas-adsorbing sheet. This is to provide an air purification filter having the ability to remove basic substances without impairing the excellent removal performance of the above-mentioned activated carbon carrying amine compounds.

The basic gas-adsorbing sheet used in the air purification filter of the present invention is not particularly limited, but is preferably a sheet-like material having a basic gas-adsorbing agent carried thereon.

The basic gas-adsorbing agent is not particularly limited. For example, malic acid, citric acid,
Organic monocarboxylic acids such as tartaric acid, organic polycarboxylic acids and the like are preferably used.

In the air purifying filter of the present invention, the basic gas-adsorbing sheet is prepared separately from the above-mentioned adsorbent (the activated carbon carrying amine compound itself or a molded article thereof).
It is preferable that the filter is formed by combining (for example, laminating) both (a basic gas-adsorbing sheet and an adsorbent) into a pleated shape or a honeycomb shape. When the above-mentioned basic gas-adsorbing agent is overlaid on the adsorbent of the present invention, or is carried on a carrier activated carbon, the amine compound of the present invention and the above-mentioned basic gas-adsorbing agent are mixed and supported. This is because the reduction is large or the properties change due to a chemical reaction between the two, and the excellent removal characteristics of the adsorbent of the present invention with respect to lower aldehydes are impaired.

A specific example of the air purifying filter of the present invention is a direct-flow type air purifying filter obtained by laminating a sheet containing activated carbon carrying an amine compound and a basic gas-adsorbing sheet and molding the sheet into a pleated shape. Filter.

Another embodiment of the air purification filter of the present invention is a honeycomb-shaped filter in which the flute portion or the liner portion is constituted by a sheet containing the above-mentioned activated carbon carrying an amine compound, and the other is constituted by a basic gas-adsorbing sheet. This is a parallel-flow type air purification filter molded into a shape.

The sheet containing the activated carbon carrying the amine compound contains 10 to 80% by weight of the activated carbon and 5 to 50% of the supporting fibers.
It is a mixed paper made by mixing 1 to 30% by weight of water swellable fibers or heat fusible fibers. When used for a pleated air purification filter, the thickness is preferably about 0.5 to 1.2 mm in consideration of air permeability and foldability, and when used for a honeycomb air purification filter, it is necessary to secure a sufficient tubular path. It is preferably about 0.05 to 0.8 mm.

The shape of the activated carbon in the sheet containing the activated carbon carrying the amine compound is preferably fibrous or particulate. The fiber length of the fibrous activated carbon is preferably 3 to 20 mm. The average particle size of the particulate activated carbon is JIS standard sieve (JIS Z88) when used for pleated air purification filters.
01) is preferably 60 to 150 μm, and when used for a honeycomb-shaped air purification filter, a JIS standard sieve (JI
It is preferably from 5 to 50 μm in terms of SZ8801).

As the above supporting fibers, polyester,
In addition to synthetic fibers such as polyacrylonitrile, polyamide and polyolefin, cotton, hemp, wood pulp, rayon,
Glass fiber, ceramic fiber, carbon fiber and the like can be used. These fibers are preferably short fibers having a fiber length of 3 to 20 mm.

The above-mentioned water-swellable fiber or heat-fusible fiber serves as an adhesive component during mixing. Examples of the water-swellable fiber include polyvinyl alcohol fiber, and examples of the heat-fusible fiber include polyethylene fiber and polypropylene-polyethylene composite fiber. These fibers preferably have a fiber length of 20 mm or less.

An ordinary corrugated cardboard manufacturing machine can be used for forming the honeycomb shape. That is, a flat sheet (liner portion) is joined to one or both sides of a corrugated sheet (which becomes a flute portion) to form a corrugated cardboard, and the obtained cardboard is laminated horizontally or in a roll shape. Formed in a honeycomb shape.

The thickness of the tubular path formed when the laminate is formed is determined by the wave pitch and wave height of the corrugated sheet, and affects the pressure loss and the moving speed of the gas component when flowing air. In the honeycomb-shaped air purification filter of the present invention, a preferable wave pitch is 30 to 150 per 30 cm, and a preferable wave height is 0.6 to 3.0 mm. The value obtained by dividing the wave height by the thickness of the sheet is preferably 3 or more.

[0048]

The present invention will be described in detail below with reference to examples. The method of evaluating the adsorbent and the air purification filter obtained in this example is described below.

(Evaluation of Acetaldehyde Removal Performance of Adsorbent) A 40 mg sample of an adsorbent was packed in a glass column having an inner diameter of 8 mmφ, and this was filled with 13 ppm of acetaldehyde to a relative humidity of about 20.
% Air was continuously circulated at 2 L / min. The gas on the upstream and downstream sides of the adsorbent was sampled at regular intervals, the acetaldehyde concentration was measured by gas chromatography with FID, and the acetaldehyde removal efficiency was determined from the ratio. The value of this removal efficiency is calculated as the integrated flow rate (the time since the start of distribution and the
2L / min) to obtain a decay curve of the removal efficiency (FIG. 1). Next, the accumulated acetaldehyde adsorption amount of each adsorbent was determined from the attenuation curve up to the integrated flow rate of 100 L and the area surrounded by the vertical and horizontal axes, and the acetaldehyde adsorption capacity per unit weight of the adsorbent (mg / g) was calculated from this. The larger the adsorption capacity is, the more excellent the acetaldehyde removal performance is.

(Evaluation of Removal Performance of Air Purification Filter) An air purification filter sample was attached to an air purifier in an acrylic 1 m ³ box, and test gas was set in the box so that the initial concentrations were 5 ppm for acetaldehyde and 30 ppm for ammonia, respectively. (Temperature 25 ° C, relative humidity 50%), the air purifier was operated at a flow rate of 2.0 m ³ / min through the filter, and the residual concentration after 30 min was measured to calculate the removal efficiency of each gas. . The concentration of acetaldehyde was measured by gas chromatography with FID.
The ammonia concentration was measured with a gas detector tube. The higher the removal efficiency for both gases, the better the air purification filter is in the removal performance.

(Example 1) Commercially available granular activated carbon 60-140 mesh (specific surface area 1480 m ² / g, surface acid group content 0.55 meq / g) having ordinary adsorption characteristics as a base activated carbon,
It is kept at 800 ° C for 3 hours in a nitrogen atmosphere, and then cooled to 300 ° C or less in that atmosphere and taken out.
m ² / g and a carrier activated carbon having a surface acidic group content of 0.27 meq / g were obtained.

100 parts by weight of this carrier activated carbon were immersed in an aqueous solution consisting of 15 parts by weight of p-anisidine and 300 parts by weight of water and stirred at room temperature for 10 minutes. After that, it is filtered by suction and drained.
Dry at 24 ° C for 24 hours, surface acid group content 0.22meq / g, specific surface area
1050 m ² / g of adsorbent a was obtained.

Using the same carrier activated carbon, m-anisidine and polyethyleneimine were supported in the same manner in place of p-anisidine to obtain adsorbents b and c, respectively.

(Comparative Example 1) Using the same activated carbon carrier as in Example 1, except that the amine compound was changed, the particles were supported in the same manner as in Example 1 to obtain adsorbents. The amine compounds used were p-aminobenzoic acid (adsorbent d), p-phenylenediamine (adsorbent e), benzylamine (adsorbent f), ethylenediamine (adsorbent g), and n-hexylamine (adsorbent).
h), polyallylamine (adsorbent i).

Example 2 A 10-30 mesh coal-based raw material was carbonized at 800 ° C., and then the combustion gas (water vapor concentration of about 20
%) At 950 ° C. until the specific surface area exceeded 1200 m ² / g. Thereafter, the mixture was cooled to 300 ° C. or lower while being kept in a container purged with nitrogen gas to obtain activated carbon having a specific surface area of 1210 m ² / g and a surface acidic group content of 0.05 meq / g. This was pulverized and sieved to obtain a 60-140 mesh carrier activated carbon, which was loaded with p-anisidine in the same manner as in Example 1 to obtain an adsorbent j.

(Comparative Example 2) The base activated carbon used in Example 1 was used as a carrier without any treatment, and p-type was obtained in the same manner as in Example 1.
An adsorbent k was obtained by supporting anisidine. As an adsorbent having an increased amount of p-anisidine, 30 parts by weight of p-anisidine was supported on 100 parts by weight of the same untreated activated carbon carrier to obtain adsorbent l.

The above adsorbent was evaluated for acetaldehyde adsorption capacity by the method described above. FIG. 1 shows a decay curve of the removal efficiency of the adsorbents a and d. Tables 1 and 2 show the acetaldehyde adsorption capacities of the respective adsorbents.

[0058]

[Table 1]

[0059]

[Table 2]

As shown in Table 1, the amount of surface acidic groups was 0.3 m
Although the adsorbent having a specific surface area of not more than eq / g and a specific surface area of not less than 800 m ² / g and the supported amine compounds of polyethyleneimine, m-anisidine and p-anisidine has excellent acetaldehyde removal performance (Example 1), It can be seen that the adsorbent supporting the amine compound (Example 2) has a low removal performance.

As shown in Comparative Example 2, even when an amine compound having a large activity for reacting with acetaldehyde was carried, the amount of surface acidic groups of the adsorbent was larger than 0.3 meq / g, or the specific surface area was less than 800 m ² / g. In some cases, the acetaldehyde removal performance is inferior to that of the adsorbent of the present invention (Examples 1 and 2). FIG. 2 is a diagram showing the relationship between the specific surface area of the adsorbent and the amount of surface acidic groups. The colored portions in the figure are the ranges of the specific surface area and the surface acidic group content of the adsorbent of the present invention.

(Example 3) Activated carbon having a specific surface area of 1390 m ² / g and an average particle diameter of 105 μm having a surface acidic group content of 0.27 meq / g and an amine compound-supported activated carbon carrying p-anisidine in the same manner as in Example 1 was prepared. Obtained. In a round paper machine, a basis weight of 150 g / m ² consisting of 68% by weight of this activated carbon, 19% by weight of rayon, and 13% by weight of polyvinyl alcohol as a binder, and a thickness of 0.8m
m was prepared. In a wet state, a sheet consisting of 19 parts by weight of polypropylene, 66 parts of rayon, and 15 parts of polyvinyl alcohol fiber (basis weight 30 g / m ² , thickness 1.
0 mm) and dried at 120-130 ° C. Next, an impregnating liquid containing malic acid 10% by weight as a basic gas adsorbing agent was applied to the sheet side not containing the amine compound-supported activated carbon by a gravure direct method. The amount of malic acid impregnated was 17% by weight based on the sheet. Next, this laminated sheet was fold-folded to a peak height of 20 mm by a gear-type fold-folding device to obtain a pleated air purification filter having a pitch of 3.8 mm and a filter medium development area of 0.44 m ² .

Example 4 65% by weight of activated carbon having a specific surface area of 1390 m ² / g, a surface acidic group content of 0.27 meq / g, an average particle diameter of 20 μm,
30% by weight of pulp and 5% by weight of polyvinyl alcohol fiber are made with a round paper machine, thickness 0.25mm, bulk density 0.3g / cc
Activated carbon paper was obtained. Then, an impregnating solution containing 15% by weight of p-anisidine was applied to this paper by a dip coating method, and dried (8% by weight of p-anisidine supported on activated carbon) was used as a flute portion. An activated carbon paper containing 7% by weight of malic acid was impregnated by dip coating and dried (malic acid carrying amount of 12% by weight based on activated carbon) as a liner portion, with a wave pitch of approximately 3.1 mm and a wave height of approximately 3.1 mm. A 2 mm single cardboard was molded. Stack this single cardboard to a height of 65
A honeycomb-shaped air purification filter having a thickness of 20 mm and a layer length of 20 mm was produced.

Table 3 shows the evaluation results of the acetaldehyde and ammonia removal performance of the air purification filters of Examples 3 and 4. From these results, it is understood that the air purification filter of the present invention shows excellent removal performance for both acetaldehyde and ammonia.

[0065]

[Table 3]

[0066]

The adsorbent and the air purification filter of the present invention carry an amine compound which is safe and essentially has a large activity for reacting with lower aldehydes, and has a surface structure such that the activity is effectively utilized. Contains activated carbon, whereby the supported amine compound easily reacts with the lower aldehyde adsorbed in the pores of the activated carbon, thereby exhibiting extremely excellent lower aldehyde removal performance. Further, when the amine compound-carrying activated carbon is used as an air purification filter, a filter having a capability of removing basic substances can be obtained without impairing the excellent removal performance of the activated carbon.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of an attenuation curve of acetaldehyde removal efficiency.

FIG. 2 is a diagram showing the relationship between the specific surface area of an adsorbent and the amount of surface acidic groups.

Claims (7)

[Claims] 1. Polyethyleneimine, m-anisidine,
An adsorbent comprising activated carbon carrying at least one selected from the group consisting of p-anisidine, wherein the activated carbon has a surface acidic group content of 0.3 meq / g or less. 2. The adsorbent according to claim 1, wherein a specific surface area of the activated carbon measured by a BET method is 800 m ² / g or more. 3. The adsorbent according to claim 1, which is used for removing lower aldehydes. 4. A filter formed in a pleated or honeycomb shape, wherein at least one selected from the group consisting of polyethyleneimine, m-anisidine and p-anisidine is supported, and the amount of surface acidic groups is Is 0.3me
An air purifying filter comprising activated carbon of q / g or less. 5. The air purification filter according to claim 4, wherein a specific surface area of the activated carbon measured by a BET method is 800 m ² / g or more. 6. The air purification filter according to claim 4, further comprising a basic gas-adsorbing sheet. 7. The surface acidic group content is 0.5 meq / g or less, and the specific surface area measured by the BET method is 1200.
m to ² / g or more in which the activated carbon, polyethyleneimine, m
-A method for producing an adsorbent, comprising supporting at least one member selected from the group consisting of anisidine and p-anisidine.