JPH09154927A - Deodorizing material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable combination of a normal temperature catalytic action and an adsorbing action in a normal atmosphere by forming a molded body from a mixture containing an active carbon, a catalyst and a binder. SOLUTION: Active carbon, a catalyst and a binder are mixed physically and formed into a molded body. The binder herein used is preferably polysaccharide or a derivative thereof. The catalyst herein used is preferably activated alumina or the like. For example, an aqueous solution of chloroplatinic acid is added to an activated alumina powder to be kneaded by a ball mill and fired and crushed at about 500 deg.C. A colloidal silica aqueous solution, water and magnesium silicate are added and mixed by the ball mill to adjust a catalyst slurry. The catalyst slurry is mixed with an active carbon, methyl cellulose, methanol and water and the mixture thus obtained undergoes an extrusion molding to form a honey comb-like deodorizing body.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deodorizer used at room temperature such as deodorization of exhaust gas from combustion equipment or cooking equipment, or deodorization in dryers, refrigerators, air conditioners and the like.

[0002]

2. Description of the Related Art Conventionally, a deodorizing device has mainly used a method of adsorbing a gaseous malodorous substance with an adsorbent such as activated carbon or zeolite for deodorizing. Further, by arranging an ozone generator in the apparatus to oxidize and decompose a malodorous component with ozone gas, or by providing an oxidative decomposition catalyst such as a noble metal near a heat source such as a flame or a heating element, the catalyst is heated and activated, A method of deodorizing an odor substance by oxidative decomposition was also used.

[0003]

However, the conventional deodorizing method has the following problems. In the physical adsorption deodorization method using activated carbon or the like, since adsorption is physical adsorption, the ability to adsorb odor at low concentrations is poor. Further, when the adsorbed amount reaches saturation, it does not exhibit an adsorbing action, and the adsorbent itself such as activated carbon may become an odor source. Although the deodorization method using ozone gas can be used at room temperature, ozone gas adversely affects the human body, and therefore there is a risk of danger at the time of leak. Since the deodorization method using an oxidative decomposition catalyst requires a heating element,
It is not suitable for deodorizing devices such as refrigerators and cooling equipment where it is difficult to install a heating element in the air passage. In addition, it is not economical considering the cost of energy required for heat generation. Further, in order to efficiently generate heat, the deodorant body is limited in shape. In order to solve these problems, a deodorant having both a normal temperature catalytic action and an adsorption action in a normal atmosphere has been desired.

[0004]

The room temperature deodorizer of the present invention comprises:
It consists of a molded body of a mixture containing activated carbon, a catalyst and a binder. By physically mixing the activated carbon and the catalyst together with the binder, both the chemisorption action of the catalyst and the physical adsorption action of the activated carbon can be made to function. Moreover, the synergistic effect of both can be exhibited. Moreover, it is preferable that the binder is composed of a polysaccharide or a derivative thereof.
The ability to adsorb odorous molecules such as a hydroxyl group, a carbonyl group and an amino group possessed by a polysaccharide or a derivative thereof can be used.
That is, the binder itself can also function as an adsorbent. Further, the binder is silica sol,
It is preferably composed of at least one selected from the group consisting of alumina sol and titania sol. By using these inorganic binders, the hardness and mechanical strength of the deodorant can be improved. Further, this makes it possible to adsorb any molecule having a diameter smaller than the pore diameter by the physical adsorption action.

Further, it is preferable that the binder is at least one selected from the group consisting of silica sol, alumina sol and titania sol, and a polysaccharide or a derivative thereof. It is possible to obtain a deodorant that satisfies both mechanical strength and odor adsorption performance. Further, the catalyst is preferably at least one selected from the group consisting of activated alumina, rare earth element-containing alumina, zeolite, magnesium silicate and silica. The zeolite is preferably at least one selected from the group consisting of hydrophilic zeolite A type and hydrophobic zeolite pentasil type, mordenite, Y type and β type.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Specific examples will be described below. <Example 1> Aqueous chloroplatinic acid solution was added to activated alumina powder, and the mixture was sufficiently kneaded using a ball mill, then baked at 500 ° C and pulverized to prepare an alumina powder carrying 1.5 wt% of Pt. 130 g of this Pt-supported alumina powder (hereinafter referred to as Pt / alumina) and 20 w of silica
400 g of colloidal silica aqueous solution containing t%, 50 g of water,
130 g of pentasil-type zeolite (H-ZSM-5),
And 60 g of magnesium silicate were thoroughly mixed using a ball mill to prepare a catalyst slurry.

Activated carbon, methyl cellulose, methanol and water are mixed in a predetermined amount with the catalyst slurry, and activated carbon 43
A mixed solution of wt%, catalyst (solid content other than activated carbon, the same applies hereinafter), 9 wt% of methyl cellulose, 4 wt% of methanol, and 4 wt% of water was prepared. This was extruded and molded, and dried to prepare a honeycomb deodorant body made of a physical mixture of activated carbon, a catalyst and a binder. In addition, this deodorant body has a size of 70 mm.
× 40 mm × 25 mm, having 400 cells per square inch, the weight of the catalyst in the deodorant was 4.0 g, and the weight of activated carbon was 4.3 g. This is the deodorant product of Example 1.

A cordierite honeycomb carrier having a size of 70 mm × 40 mm × 25 mm and having pores of 400 cells per square inch was dipped in the above catalyst slurry and dried to carry 4.0 g of the catalyst. This is designated as the deodorant of Comparative Example 1-1. In addition, by mixing methyl cellulose and activated carbon in a weight ratio of 9:43, extruding the mixture, and drying it, a size of 70 mm is obtained.
× 40 mm × 25 mm, weight 5.2 g, 400 cells /
A honeycomb-shaped deodorizer made of activated carbon having pores of square inch was prepared. This is the deodorant product of Comparative Example 1-2. Furthermore, a honeycomb-like deodorant body made of activated carbon supporting a catalyst was prepared by immersing the same deodorant body as in Comparative Example 1-2 in the catalyst slurry and drying. The amount of catalyst supported was set to 4.0 g, which is the same as that of the deodorized product of Comparative Example 1-1. This is the deodorant product of Comparative Example 1-3.

The above-mentioned four types of honeycomb deodorizing materials were evaluated by the following methods. An odorous gas was passed through the deodorant body using a flow type fixed bed reactor until the adsorbent reached saturation of adsorption. The amount of adsorption was determined by analyzing the gas concentrations upstream and downstream of the deodorant at this time. The analysis was performed by gas chromatography. Methyl mercaptan for odorous gas,
Air having a concentration of either trimethylamine or acetaldehyde of 10 ppm was used. The results of these odorous gas adsorption tests are shown in Table 1.

[0010]

[Table 1]

As shown in Table 1, the deodorant of Example 1, that is, the deodorant in which activated carbon and a catalyst were physically mixed, was a cordierite honeycomb deodorant carrying a catalyst (Comparative Example 1-1). Activated carbon honeycomb deodorizer (Comparative Example 1-2)
It can be seen that the adsorption capacity is dramatically increased compared to. Further, as compared with the honeycomb-shaped deodorant having a catalyst layer formed on the surface of activated carbon (Comparative Example 1-3), regarding trimethylamine, the deodorant of Example 1 obtained by physically mixing activated carbon and a catalyst exhibits superior performance. . However, in the case of methyl mercaptan, the performance is equivalent, and in the case of acetaldehyde, the honeycomb deodorizer made of catalyst-supporting activated carbon is superior. By thus using the catalyst and the activated carbon in combination, even an odor that is difficult to be adsorbed only by the activated carbon can be changed into a molecule that is easily adsorbed by the activated carbon by the action of the catalyst and can be adsorbed to the activated carbon. The main function of the catalytic reaction is the oxidative decomposition of odors, but when used in combination with activated carbon, such a synergistic effect can be exhibited.

Next, the odor desorption characteristics of the adsorption-saturated deodorant were examined. The experiment was conducted as follows. Using the same flow type fixed bed reactor as described above, air was passed at 100 ml / min through the deodorant adsorbed and saturated with methyl mercaptan, and the odor in the air downstream of the deodorant was sensory evaluated. Sensory evaluation was started at the time of air injection, 30, 60, 1
The odor after 20 minutes was evaluated. The sensory evaluation criteria are that odorlessness is 0, odor intensity is 0, barely perceivable odor (detection threshold concentration) is odor intensity 1, weak odor (cognitive threshold concentration) is odor intensity 2, odor is easily perceivable. The strength was 3, the strong odor was odor strength 4, and the strong odor was odor strength 5. The results of the sensory evaluation test are shown in Table 2.

[0013]

[Table 2]

As shown in Table 2, the deodorant of Example 1 prepared by physically mixing activated carbon and a catalyst has the lowest sensory evaluation value, and the tendency of odor desorption from the saturated adsorbed deodorant is low. Recognize. Deodorant consisting only of activated carbon (Comparative Example 1-
In 2), because of adsorption by physical adsorption, the tendency of desorption is highest. On the other hand, in the deodorant composed of only the catalyst (Comparative Example 1-1), desorption of by-products of the catalytic reaction occurred. Further, a deodorant body having a catalyst layer formed on the surface of activated carbon (Comparative Example 1-
In 3), some desorption occurred because the by-product of the catalytic reaction generated on the surface of the catalyst layer could not be adsorbed and removed by the activated carbon. As described above, the room temperature deodorizer physically mixing the activated carbon and the catalyst quickly adsorbs the by-product produced by the reaction of the noble metal or zeolite in the catalyst layer on the activated carbon, prevents the diffusion to the outside, and the catalyst by the by-product It has the function of preventing layer poisoning. Due to such an action, an extremely large amount of odor can be adsorbed as compared with the conventional adsorbent, and the deodorant can be used for a long period of time. Also, even if the odor is desorbed from the activated carbon,
Since the catalyst is present in the vicinity of the activated carbon due to the physical mixture of the activated carbon and the catalyst, the desorbed molecules can be adsorbed and removed to prevent the diffusion to the outside. Therefore, the room temperature deodorizer of this example is unlikely to become an odor source even during long-term use.

Example 2 Pt / alumina powder 130
g, activated alumina powder simple substance 130 g, silica 20 wt
% Aqueous colloidal silica solution 400 g, pentasil-type zeolite (H-ZSM-5) 130 g, magnesium silicate 60 g, activated carbon 430 g, water 40 g, methanol 4
No. 0 g and 90 g of methyl cellulose shown in Table 3. A combination of 1 to 15 was thoroughly mixed and dried to prepare a honeycomb deodorant body having a size of 70 mm × 40 mm × 25 mm having pores of 400 cells per square inch. In this deodorized product, the weight of activated carbon and cellulose was 5.2 g. The catalyst was thoroughly mixed with a ball mill into a slurry before being mixed with activated carbon, a binder and the like.

A methyl mercaptan purification test was carried out on these deodorized products and, as a comparative example, a honeycomb-shaped deodorized product prepared by using only activated carbon and cellulose (the same as in Comparative Example 1-2 above). In the purification test, the deodorant was placed in a cubic fluororesin container having a volume of 250 liters, methyl mercaptan was injected into the container so that the concentration became 8 ppm, and the gas in the container was stirred with a fan for 90 minutes. After that, it was performed by examining the methyl mercaptan concentration in the container.
The measurement was performed by gas chromatography. In addition, a similar purification test was performed on trimethylamine. 2
The results of three purification tests are shown in Table 3.

[0017]

[Table 3]

As shown in Table 3, in the above-mentioned purification test, the noble metal (P
t), activated alumina, pentasil-type zeolite, (H-
ZSM-5), magnesium silicate and colloidal silica. Deodorant of 15 shows the best performance.

<Example 3> In order to investigate the odor adsorption performance of the zeolite species, the following study was conducted. Using 130 g of Pt / alumina, 400 g of colloidal silica aqueous solution containing 20 wt% of silica, 130 g of zeolite, 60 g of magnesium silicate, 430 g of activated carbon, 40 g of water, 40 g of methanol, 90 g of methyl cellulose, and 90 g of methyl cellulose, a deodorant body was prepared in the same manner as in Example 2. did. At this time, as the zeolite, copper ion-exchanged type A zeolite (Cu-
A), sodium ion-exchanged pentasil-type zeolite (Na-ZSM-5), hydrogen-ion-exchanged Y-type zeolite (HY), sodium-ion-exchanged β-type zeolite (Na-β), and hydrogen-ion-exchanged mordenite ( A mixture of two kinds of (H-mordenite) at a weight ratio of 1: 1 was used. These deodorants were subjected to a purification test using ammonia, which is a hydrophilic odor component, and dimethyl sulfide, which is a hydrophobic odor component. In the purification test, the deodorizer was placed in a 250 liter cubic container made of fluororesin, and the concentration of the odorous component was 8 pp.
One of the two odors was injected into the container so that the m became m, and the gas in the container was stirred by a fan for 90 minutes, and the odor concentration was examined. The measurement was performed by gas chromatography. Table 4 shows the results of each odor purification test.

[0020]

[Table 4]

As shown in Table 4, pentasil type, H-
The deodorant containing any one of Y, Na-β, and H-mordenite and the A-type zeolite exhibits excellent adsorption performance for both hydrophilic and hydrophobic odors.

<Example 4> Deodorizers were molded using various organic binders, and their moldability and adsorption characteristics were examined. As the organic binder, any one of ammonium salt or sodium salt of carboxymethyl cellulose, hydroxyethyl cellulose, sodium lignin sulfonate, bisphenol A, resole, and urea resin adhesive was used. For ammonium salt or sodium salt of carboxymethyl cellulose, hydroxyethyl cellulose and sodium lignin sulfonate, the same catalyst slurry as in Example 1 was used, and these organic binder, activated carbon, catalyst, water and methanol were used in a weight ratio. A kneaded material was extruded and molded at a ratio of 1: 5: 5: 1: 1, and dried to prepare a honeycomb-shaped deodorant body. For bisphenol A, resol, or urea resin adhesive, a mixture of 130 g of Pt / alumina, 80 g of silica, 130 g of pentasil-type zeolite (H-ZSM-5), and 60 g of magnesium silicate was used as an organic binder. A honeycomb-shaped deodorizer was produced by extruding a mixture of activated carbon and a catalyst in a weight ratio of 1: 5: 5 and curing the mixture by heat treatment. The produced deodorant has a size of 70 mm × 40 mm × 25 mm and has 400 cells per square inch. The moldability of these deodorants was evaluated. Furthermore, in order to investigate the effect of the binder on the deodorizer at room temperature, the same dimethyldisulfide purification test as in Example 3 was performed. Table 5 shows the results.

[0023]

[Table 5]

As shown in Table 5, the room temperature deodorizer using a binder made of a polysaccharide or its derivative was superior in moldability and deodorizing performance to other binders. This is because by using an organic binder in which a polysaccharide and its derivative are dissolved in water, it is possible to use the ability to adsorb odorous molecules such as a hydroxyl group, a carbonyl group, and an amino group possessed by the polysaccharide and its derivative. Conceivable. That is, the binder itself can also function as an adsorbent.

Example 5 In order to investigate the water resistance of a deodorant composed of an organic binder, the following study was conducted. Seven types of honeycomb deodorizing bodies shown in Table 5 produced in the same manner as in Example 4 were immersed in water, and the appearance was observed. Table 6 shows the results.

[0026]

[Table 6]

From the results shown in Table 6, it was confirmed that the polysaccharide and its derivative, that is, the deodorant using the ammonium salt or sodium salt of carboxymethyl cellulose as a binder has water resistance.

<Example 6> Deodorizers were prepared using various inorganic binders, and their moldability and adsorption properties were examined. The binder used for molding is silica sol, alumina sol, titania sol, bentonite, sodium silicate,
Six types of lithium silicate were used. Using the same catalyst slurry as in Example 1, these binders, activated carbon and catalyst were mixed in a weight ratio of 1: 5: 5, and an appropriate amount of water was added to the mixture to give a constant viscosity, and the mixture was kneaded. A honeycomb deodorizer having a size of 70 mm × 40 mm × 25 mm having 400 cells per square inch was prepared by extrusion molding and drying. The moldability of the room-temperature deodorant thus prepared was evaluated. Table 7 shows the results.

[0029]

[Table 7]

As shown in Table 7, by using silica sol, alumina sol or titania sol, a deodorant having high hardness was obtained although some fine cracks were observed.

<Example 7> Using a binder obtained by mixing an organic binder such as a polysaccharide or a derivative thereof having excellent moldability and deodorizing performance with an inorganic binder such as silica sol, alumina sol, titania sol, moldability of a deodorant,
The effect on deodorizing performance was examined. The mixing ratio was 1: 1 by weight of solids. Using the same catalyst slurry as in Example 1, the mixed binder thus prepared, activated carbon and catalyst (solid content) were mixed at a weight ratio of 1: 5: 5, kneaded, extruded and dried to give 400 per square inch. A honeycomb deodorant body having a size of 70 mm × 40 mm × 25 m having cell pores was produced. The moldability and deodorizing performance of the honeycomb-shaped deodorizing body thus produced were evaluated. The deodorizing performance was evaluated by the same dimethyldisulfide purification test as in Example 4. These test results are combined with the results of the deodorant using the organic binder having good performance obtained in Example 4 and the result of the deodorant using the inorganic binder having good performance also obtained in Example 6. It shows in Table 8.

[0032]

[Table 8]

From the results shown in Table 8, the deodorants obtained by using the inorganic binders such as silica sol and alumina sol together with the organic binders of polysaccharides and their derivatives are more excellent than the deodorants obtained by using the organic binder and the inorganic binder alone. It was found that it has moldability and deodorizing performance.

When molding the deodorant, a kneaded mixture of activated carbon, a catalyst and a binder is used. A layered clay compound such as bentonite may be added to control the viscosity of the kneaded product. As the activated carbon, it is also possible to use the activated carbon modified by the functional group in the activated carbon pores by surface-treating ordinary activated carbon with an organic compound. As the activated alumina, metastable alumina such as β, γ, δ, η, θ, ρ and χ can be used. Further, the activity can be further improved by supporting a promoter such as a rare earth oxide on the surface of activated alumina. Further, the activated alumina may contain an alkaline earth metal. In particular, by adding barium to activated alumina, the thermal stability of alumina can be improved. Pd as well as Pd can be used as the noble metal. Particularly, when both Pt and Pd are used, a particularly large effect is obtained. this is,
The oxidative decomposition power of Pt and Pd is higher than that of Rh and Ih,
This is because the use of both Pt and Pd results in higher activity.

Zeolites include A type, pentasil type,
Although mordenite, Y type, β type, etc. can be used,
Those obtained by ion-exchanging these zeolites with a metal salt can also be used. In addition, by incorporating activated alumina, rare earth element-containing alumina, noble metal, zeolite, and silica as a catalyst into the deodorant body, it becomes possible to perform adsorption with chemical changes such as combustion of odor molecules, partial oxidation, dehydrogenation, and condensation. . In addition, the zeolite shares at least one of a hydrophilic zeolite, A type, and a hydrophobic zeolite, pentasil type, mordenite, Y type, and β type, so that odor molecules can be obtained regardless of hydrophilicity or hydrophobicity. Can be chemisorbed.

[0036]

INDUSTRIAL APPLICABILITY As described above, by using the deodorant product of the present invention, excellent room temperature catalytic deodorization becomes possible. That is, due to the interaction between the catalyst and the activated carbon, the deodorizing performance was improved as compared with the performances of the catalyst and the activated carbon. further,
The deodorant has an extremely high odor adsorption capacity and a low tendency of deodorizing the odor from the deodorant, which allows the deodorant to be used for a long period of time.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location B01J 23/10 B01J 23/10 Z 29/06 29/06 Z (72) Inventor Hidenobu Wakita Osaka 1006 Kadoma, Kadoma-shi, Fuchu Matsushita Electric Industrial Co., Ltd.

Claims (6)

[Claims] 1. A deodorant body comprising a molded body of a mixture containing activated carbon, a catalyst and a binder. 2. The deodorant product according to claim 1, wherein the binder comprises a polysaccharide or a derivative thereof. 3. The deodorant body according to claim 1, wherein the binder comprises at least one selected from the group consisting of silica sol, alumina sol and titania sol. 4. The deodorant product according to claim 1, wherein the binder is at least one selected from the group consisting of silica sol, alumina sol and titania sol, and a polysaccharide or a derivative thereof. 5. The deodorant according to claim 1, wherein the catalyst is at least one selected from the group consisting of activated alumina, rare earth element-containing alumina, zeolite, magnesium silicate, and silica. 6. The deodorization according to claim 5, wherein the zeolite is at least one selected from the group consisting of hydrophilic zeolite A type and hydrophobic zeolite pentasil type, mordenite, Y type and β type. body.