JP2001096149A - Porous adsorbent and filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a porous adsorbent and a filter capable of efficiently removing lower aldehydes at ordinary temperature and excellent in heat resistance, safety, and stability of the adsorptive capability. SOLUTION: The porous adsorbent is an adsorbent obtained by depositing an urea compound having ureid bond in a molecule in a porous carrier and molding the carrier. The filter is filter for air cleaning obtained by molding a porous adsorbent produced by depositing aniline as the urea compound and salts of transition metals in a porous carrier of such as an activated carbon.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a porous adsorbent and a filter. More specifically, the present invention relates to a porous adsorbent effective for adsorbing and removing aldehydes contained in odors generated from domestic and working environments, particularly lower aldehydes represented by formaldehyde and acetaldehyde, and to a filter formed of the same.

[0002]

2. Description of the Related Art Various deodorants have been developed for the purpose of removing odors present in home and work environments. In recent years, among the components contained in these odors, particularly lower aldehydes such as formaldehyde and acetaldehyde have been pointed out as having effects and harmfulness in home and work environments. Requested.

Hitherto, in order to remove such odors, porous adsorbents such as activated carbon, activated clay, silica gel, and activated alumina have been frequently used, and in particular, activated carbon has been widely used. However, these adsorbents have a low ability to adsorb lower aldehydes, and when deodorizing and removing in various environments, it is necessary to use a considerable amount of adsorbent.

On the other hand, various adsorbents have been developed in which various organic compounds and inorganic compounds are supported on a porous carrier to enhance the ability to adsorb lower aldehydes. For example, aniline, aniline, Hydrazines, aliphatic first
Adsorbents impregnated with organic compounds such as secondary amines, secondary amines, and saturated cyclic secondary amines have been proposed (for example, JP-B-60-54095, JP-A-55-1).
59836, JP-A-60-48138, JP-A-4-358536, and the like. In addition, a porous carrier such as activated carbon, an acidic ammonium salt, a sulfite, a metal oxide, a metal sulfate, a metal acetate, a metal carboxylate and the like, and a platinum compound as a catalyst, and a platinum compound as described above. Those supported on an adsorbent have also been proposed.

[0005]

However, an adsorbent supporting an organic compound does not have good stability over time of an adhering substance, and also poses a problem of health hazards such as odor. Furthermore, such adsorbents are often used after being subjected to some kind of secondary processing in addition to being used alone. Therefore, heat resistance at the time of secondary processing is required, and the surface of odor and the processing at the time of processing are required. The subsequent performance stability was not satisfactory.

[0006] In general, those loaded with an inorganic compound do not have a sufficient adsorption rate, and those loaded with a catalyst generally have low removal performance at room temperature. As described above, the adsorbents conventionally proposed are not necessarily sufficiently satisfactory for removal of lower aldehydes. Therefore, an object of the present invention is to provide a porous adsorbent and a filter that efficiently remove lower aldehydes and are excellent in heat resistance, safety, and stability of adsorption performance.

[0007]

Means for Solving the Problems The present inventors have conducted intensive studies on a porous adsorbent impregnated with a urea compound, which was previously unsuitable for the adsorption of lower aldehydes. The present inventors have found that a porous adsorbent in which a urea compound is impregnated on a porous carrier is excellent in adsorbing lower aldehydes, and have reached the present invention. That is, the present invention is a porous adsorbent obtained by attaching a urea compound having a urea bond in a molecule to a porous carrier. Another aspect of the present invention is a filter formed from the porous adsorbent.

The urea compound having a urea bond in the molecule used in the present invention refers to a urea compound in which at least one hydrogen atom of urea is substituted with an alkyl group or an acyl group, and has either a chain structure or a cyclic structure. You can do it.

Among such urea compounds, a chain urea compound refers to a urea compound in which a urea bond does not directly form a cyclic structure, such as methyl urea, ethyl urea, dimethyl urea, diethyl urea, and tetramethyl urea. , Acetyl urea,
Acetyl methyl urea such as N-acetyl-N'-methyl urea, phenyl urea, diphenyl urea and the like can be mentioned.

Of the urea compounds, cyclic urea compounds include 2-imidazolidinone (ethylene urea), pseudouric acid (ureidobarbituric acid), hydantoin,
Allantoin, alloxanic acid, parabanic acid (oxalyl urea), 5,5-methylhydantoin (acetylurea), urazole, barbituric acid (malonyl urea), alloxane (mesoxalyl urea), dialluic acid (hydroxymalonyl urea), uramil (amino barbi) Turic acid), dilituric acid (nitrobarbituric acid), violuric acid (isonitrosobarbituric acid), uracil (2,6-hydroxypyrimidine), thymine (5-methyluracil), isocyanuric acid, uric acid (2,6 8-trioxypurine), alloxanthine and the like.

The above-mentioned urea compounds are used alone or in combination of two or more. Of these, the use of 2-imidazolidinone (ethylene urea) or pseudouric acid is preferred because the effects of the present invention are well exhibited. Also,
When the urea compound and aniline are used in combination,
Since the effects of the present invention are well exhibited and release of aniline from the carrier can be restricted, harmfulness can be suppressed, and heat resistance is excellent, so that it can be preferably used. The amount of the urea compound added to the porous carrier is 0.5 to 60% by weight, preferably 5 to 30% by weight, based on the weight of the anhydrous porous carrier.

The porous carrier used in the present invention includes:
There is no particular limitation as long as it can support a urea compound, aniline, and a transition metal, and examples thereof include activated carbon, activated clay, activated alumina, zeolite, silica gel, and montmorillonite. Among them, activated carbon is preferable in terms of gas contact efficiency due to a large specific surface area. The shape of the porous carrier may be any of granular, powdery, crushed, granular, spherical, cylindrical, fibrous, cloth, felt, sponge, and the like.

The urea compound can be supported on the porous carrier by the following method. When a water-soluble urea compound is used, the following method is employed. The compound is dissolved in water in advance, the porous carrier is immersed in the aqueous solution, and then dried to support the compound. The compound is dissolved in water in advance, this aqueous solution is sprayed on a porous carrier, and then dried to support the compound.

The following method can be used regardless of whether it is soluble or insoluble in water. An emulsion is prepared by adding the compound to a dispersant, a binder, and the like, and is dispersed on a porous carrier to carry the compound. Powder, granular, crushed or fibrous porous carrier such compound, solvent,
Add a binder and granulate into a spherical or cylindrical shape. A powdery, granular, crushed or fibrous porous carrier is added to the above emulsion, and impregnated or coated with porous polyurethane, non-woven fabric, paper or the like.

In the above method, a binder is used if necessary, and examples of the binder include carboxymethyl cellulose, acrylic emulsion, fluorinated ethylene dispersion, nitrocellulose, polyvinyl alcohol, water glass, pulp and the like. be able to. The smaller the amount of the binder used, the better.

In the present invention, when a urea compound is carried together with a salt of a transition metal, a catalytic effect is exhibited, so that the adsorption performance can be further improved, which is preferable. Examples of such transition metals include zinc, iron, copper, magnesium, nickel, titanium, and cobalt. The transition metal salt is preferably a transition metal chloride, nitrate, sulfate, phosphate, acetate, or the like. The addition amount of the transition metal compound is preferably 1 to 100% by weight, more preferably 3 to 30% by weight, based on the weight of the urea compound anhydride added to the porous carrier. Such a compound is supported on a porous carrier in the same manner as the above-described method for supporting a urea compound. At this time, it is desirable that the urea compound and the transition metal compound basically carry the urea compound first.

A porous adsorbent obtained by supporting a urea compound or the like on a porous carrier is preferably used as an air purifying agent. However, it is practical to further form a filter and use it as a filter for air purifying. Yes, preferred. In order to mold the porous adsorbent, a fine particle binder is mixed with the porous adsorbent, the surface of the porous adsorbent is coated, and pressure molding is performed. As a fine particle binder,
Those which can be heated and fused without using water or an organic solvent are preferred. From such a viewpoint, a thermoplastic resin is preferable as the binder, but a polyolefin resin such as polyethylene or polypropylene is preferable in terms of softening temperature and melting temperature. When frictional strength is required, a polyamide resin such as 6-nylon or 6,6-nylon may be used.

It is desirable that the particle size of these binders is as small as possible so as not to impair the adsorptivity of the porous adsorbent, and that the amount of the binder used is small. However, when the particle size of the binder is too small, the coat layer of the binder on the surface of the porous adsorbent becomes too thin, and the strength at the time of molding may decrease. Therefore, the central particle size is set to 1 μm or more and 30 μm or less. It is desirable. The amount of the binder used is usually 2 to 4
Although it is carried out with 0 parts by weight, as described above, it is better to carry out with as small an amount as possible from the viewpoint of preventing a decrease in the adsorption capacity.

For mixing the porous adsorbent and the binder, for example, a conventional mixer, a ribbon mixer, a static mixer, a ball mill, a sample mill, a kneader, etc., which are industrially used, can be used. is not. By utilizing static electricity generated by stirring the porous adsorbent and the resin fine particle binder, it is possible to coat the fine particles on the surface of the porous adsorbent extremely thinly and uniformly. The strength of the formed coat layer is so high that once formed, it is not easily peeled off by ordinary operations. In addition, at the time of stirring, microwaves,
Irradiation with infrared rays, far infrared rays or high frequencies can also be performed.

The porous adsorbent can be formed into an arbitrary shape such as a plate, a lattice, a honeycomb, a paper, a sheet, or the like, but it is practical to form the plate into a plate or a lattice.
preferable. In particular, by forming it into a lattice shape or a honeycomb shape, pressure loss during ventilation can be suppressed low. As the molding method, a known pressure molding method can be used, for example, a method in which a porous adsorbent is sealed in a mold frame and pressure-compressed while heating, and a roller, endless while being sprayed on a belt and heated. Examples of the method include pressure bonding with a belt or the like. In the filter thus obtained, generation of fine powder of a porous carrier such as activated carbon is extremely low. Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto.

[0021]

Example 1 As a porous carrier, a BET specific surface area of 1000 m ² / g,
Activated carbon made from coconut shells having a particle size of 20 to 40 mesh was used. As the urea compound, 2-imidazolidinone was used. A predetermined amount of 2-imidazolidinone was dissolved in water in advance to prepare a 30% by weight aqueous solution of 2-imidazolidinone. 200 g of activated carbon was put into a 2 liter tabletop mixer, and a predetermined amount of the aqueous solution was sprayed while the mixer was operating, and dried at 105 ° C. for 3 hours.
As a result, activated carbon loaded with 2-imidazolidinone was obtained as shown in FIG.

[0022]

[Table 1]

The adsorption isotherm of each adsorbent for acetaldehyde gas at 25 ° C. was measured, and the gas concentration was 10 pp.
The adsorption capacity in m was determined. Table 2 shows the results.

[0024]

[Table 2]

Example 2 Pseudouric acid-loaded activated carbon shown in Table 3 was obtained in the same manner as in Example 1 except that pseudouric acid (ureidobarbituric acid) was used as the urea compound.

[0026]

[Table 3]

The equilibrium adsorption performance of acetaldehyde was measured for each of the obtained adsorbents under the same conditions as in Example 1.
Table 4 shows the results.

[0028]

[Table 4]

Example 3 Activated carbon carrying N-acetyl-N'-methylurea shown in Table 5 was obtained in the same manner as in Example 1 except that N-acetyl-N'-methylurea was used as the urea compound.

[0030]

[Table 5]

The equilibrium adsorption performance of acetaldehyde was measured for each of the obtained adsorbents under the same conditions as in Example 1.
Table 6 shows the results.

[0032]

[Table 6]

Example 4 Activated carbon made from coconut shell having a BET specific surface area of 1000 m ² / g and a particle size of 20 to 40 mesh used in Example 1 was used as a porous carrier, and aniline and N-acetyl- N'-methyl urea was used. A predetermined amount of N-acetyl-N'-methylurea was previously dissolved in water, and 30% by weight of N-acetyl-N'-methylurea was dissolved.
An aqueous solution was prepared. 200 g of activated carbon was placed in a tabletop mixer having a capacity of 2 liters, and a predetermined amount of aniline was sprayed and supported while operating the mixer. Then, the above aqueous solution was sprayed in a predetermined amount and dried at 105 ° C. for 3 hours. N-acetyl-N'-methylurea-supported activated carbon was obtained.

[0034]

[Table 7]

The equilibrium adsorption performance of acetaldehyde on each of the obtained adsorbents was measured under the same conditions as in Example 1.
Table 8 shows the results.

[0036]

[Table 8]

Example 5 In order to check the heat resistance of the adsorbent obtained in Example 4, as shown in Table 9, each adsorbent was heat-treated at 140 ° C. in air for 3 hours.

[0038]

[Table 9]

The equilibrium adsorption performance of acetaldehyde was measured for each of the obtained adsorbents under the same conditions as in Example 1.
The results are shown in Table 10, where aniline-N-acetyl-N '
It can be seen that those carrying -methyl urea have less decrease in acetaldehyde adsorption ability than those carrying only aniline.

[0040]

[Table 10]

Example 6 As a porous carrier, the activated carbon used in Example 1 and having a BET specific surface area of 1000 m ² / g and a particle size of 20 to 40 mesh coconut shell as a raw material was used. Zinc chloride and pseudouric acid were used as loading components. A predetermined amount of zinc chloride and pseudouric acid was previously dissolved in water to prepare a zinc chloride aqueous solution and a 30% by weight aqueous solution of pseudouric acid, respectively.
200 g of activated carbon was put into a tabletop mixer having a capacity of 2 liters, and a predetermined amount of a pseudouric acid aqueous solution was sprayed and supported while operating the mixer. Then, a predetermined amount of a zinc chloride aqueous solution was sprayed,
After drying at 105 ° C. for 3 hours, activated carbon carrying zinc chloride and pseudouric acid was obtained. Table 11 shows the amount of the activated carbon obtained.

[0042]

[Table 11]

The equilibrium adsorption performance of acetaldehyde was measured for each of the obtained adsorbents under the same conditions as in Example 1.
Table 12 shows the results.

[0044]

[Table 12]

Example 7 Activated carbon 8 supported on 2-imidazolidinone obtained in Example 1
5 g and 15 g of fine powdered polyethylene having a central particle diameter of 20 μm
Was put into a mixer and mixed uniformly. This is 100m long
pour into a formwork of mx 100 mm wide x 5 mm high,
Crimping was performed at 130 ° C. for 30 minutes under a pressure of 10 kg / cm ² . There was no off-flavor during molding, and the moldability was good. After cooling, it was taken out, and its adsorption performance and bending strength were measured.

Regarding the adsorption performance, the adsorption isotherm for formaldehyde gas was measured at 25 ° C.
The adsorption capacity at 0 ppm was determined. Regarding the bending strength, a molded body having a width of 100 mm and a thickness of 5.0 mm was placed on a support at intervals of 60 mm. Place a 100mm round bar,
The load value (kgf) when breaking by applying a load from above the round bar with a push-pull gauge was defined as the bending strength. Table 13 shows the results.

[0047]

[Table 13]

Example 8 Sample No. 1 prepared in Example 1 The mixture of 2 was molded in a mold, and 4 mm in length 100 mm × width 100 mm × height 10 mm.
A grid-like molded body having cells / inch and an aperture ratio of 42% was produced. Ten of these were stacked and packed in a vinyl chloride column to form a filter for air purification. A test gas containing 5 ppm of formaldehyde at 30 ° C. and 40% RH was passed through the filter at a flow rate of 20 L / min for 24 hours, and the outlet gas concentration was measured with a gas tech detector tube (91 L). (Removal rate 70
%). On the other hand, when only the activated carbon used in Example 1 was similarly formed into a lattice shape and measured, the outlet gas concentration after passing the test gas for 5 hours was 5 ppm, which is the same as the inlet gas concentration (removal rate 0%). ).

Example 9 A plate-like molded product was produced from the adsorbents obtained in Examples 3 and 4 under the same conditions as in Example 7. Sample No. In No. 8, an aniline odor was generated during the production of the molded product, and the obtained plate-shaped molded product also had many cracks and was weak in strength. The equilibrium adsorption performance of formaldehyde was measured for each of the obtained plate-like molded bodies under the same conditions as in Example 7. Table 14 shows the results.

[0050]

[Table 14]

Example 10 In order to check the heat resistance of the plate-like molded product obtained in Example 9, as shown in Table 15, each plate-like molded product was heated at 120 ° C. in air for 5 hours.
Heat treatment was applied for a time.

[0052]

[Table 15]

The equilibrium adsorption performance of formaldehyde was measured under the same conditions as in Example 1 for each of the obtained plate-like molded bodies. The results are shown in Table 16, and it can be seen that the sample to which aniline-N-acetyl-N'-methylurea was impregnated had less decrease in formaldehyde adsorption ability than the sample to which only aniline was impregnated.

[0054]

[Table 16]

Example 11 Each adsorbent obtained in Example 6 was formed into a plate in the same manner as in Example 7, and the equilibrium adsorption performance of formaldehyde was measured. Table 17 shows the results.

[0056]

[Table 17]

From the above results, it can be seen that the porous adsorbent and the filter of the present invention efficiently adsorb lower aldehydes at room temperature, are excellent in heat resistance, and are excellent in adsorption removal performance. It is clear that when used in combination with a transition metal salt, better performance is exhibited.

[0058]

According to the present invention, it is possible to provide a porous adsorbent in which a urea compound having a urea bond is attached to a porous carrier, and a filter in which the adsorbent is formed into a plate or lattice. ADVANTAGE OF THE INVENTION The porous adsorbent and filter of this invention remove a lower aldehyde efficiently at normal temperature, and are excellent also in heat resistance, safety, and stability of adsorption performance. The porous adsorbent and the filter of the present invention can exhibit higher performance by further using a specific metal salt in combination.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masaki Fukuura 4342 Tsuruumi, Bizen City, Okayama Prefecture Inside Kuraray Chemical Co., Ltd. (72) Inventor Teruhiro Okada 4342 Tsuruumi, Bizen City, Okayama Prefecture Kuraray Chemical Co., Ltd. F-term (reference) 4C080 AA05 AA06 AA09 BB02 CC02 HH05 JJ03 JJ04 JJ06 KK08 MM18 NN01 NN05 NN14 QQ03 4D012 CA09 CA10 CB01 CG01 CG03 4G066 AA05C AA32B AA47B AA50B AA53B AB09B AB13 FA23 BA02 BA02 FA02

Claims (9)

[Claims] 1. A porous adsorbent in which a urea compound having a urea bond in a molecule is attached to a porous carrier. 2. A porous adsorbent in which aniline and a urea compound having a urea bond in a molecule are attached to a porous carrier. 3. A transition metal nitrate, chloride salt, acetate salt,
A porous adsorbent in which a phosphate or a sulfate and a urea compound having a urea bond in a molecule are attached to a porous carrier. 4. The porous adsorbent according to claim 1, wherein the urea compound is a cyclic urea compound. 5. The porous adsorbent according to claim 4, wherein the cyclic urea compound is 2-imidazolidinone or pseudouric acid. 6. The porous carrier according to claim 1, wherein said porous carrier is activated carbon.
5. The porous adsorbent according to any one of 5. 7. The porous adsorbent according to claim 1, wherein the porous adsorbent is an air purifier. 8. A filter formed by molding the porous adsorbent according to claim 1. 9. The filter according to claim 8, wherein the filter is a filter for purifying air.