JP2722891B2 - Catalyst for deodorization - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalyst used for deodorizing equipment for heating, hot water supply, drying, cooking, refrigeration, and air conditioning.

[0002]

2. Description of the Related Art Conventional deodorizing methods are known, such as activated carbon and zeolite, which deodorize by adsorbing odorous substances, and those which send odor to a heated catalyst to deodorize by oxidative decomposition. Recently, a method has been proposed in which a device having an ozone generating function is disposed in a room and an odorous component is oxidatively decomposed by ozone gas.

[0003]

However, such a conventional deodorizing method has the following problems.

As in the case of conventional activated carbon and zeolite, deodorization by adsorption of odorous substances requires replacement when the adsorption reaches saturation. Further, in the case where deodorization is performed using a catalyst, there is a problem that the deodorization cannot be performed unless the catalyst is constantly heated. Furthermore, in the odor decomposition method using ozone, a special device must be provided to control the optimum ozone generation concentration for decomposition and deodorization, there are odorous components that are difficult to decompose by ozone, and the ozone generator There is a problem in that there is a lifetime.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and has a simple structure and has an odor and harmful gas.
The has a function of divided and deodorizing which can be repeatedly used
A catalyst body is provided.

[0006]

DISCLOSURE OF THE INVENTION The catalyst for deodorization according to the present invention
Body is noble on zeolites, mineral binders and surfaces
A metal-supported inorganic oxide, wherein the inorganic oxide
Is alumina, silica, zirconia and magnesia
At least one selected from the group consisting of
And has the function of oxidative decomposition and deodorization under heating.
It is a sign .

[0007]

The catalytic body for deodorization according to the present invention has a large specific surface area.
Catalyst material supported on silica zeolite and inorganic oxide
Noble metals. Because of that,
At room temperature by adsorption and acid by noble metal under heating
It can have two deodorizing functions of chemical decomposition and deodorization. An example
For example, if ambient air comes into contact with the deodorizing catalyst,
Amine and mercaptan as components are adsorbed on zeolite
Is done. In addition, the deodorizing catalyst body is heated or heated.
Activate precious metals by bringing air into contact with the deodorizing catalyst.
As a result, the odorous substances in the air are oxidatively decomposed. This
Thus, odor substances in the air can be removed.
In addition, the deodorizing catalyst is heated to activate the noble metal
Then, at the same time, the odorous substances adsorbed on the zeolite
When the adsorption capacity of zeolite is regenerated,
The effect is called. Therefore, the catalyst body for deodorization according to the present invention
Deodorizes odorants in the surrounding air for a long time
Can maintain ability.

Here, when the noble metal salt is put in a slurry together with the zeolite and then calcined to carry the noble metal, the noble metal is also carried in the pores of the zeolite. Noble metals do not perform well because the substance cannot enter the pores. Further, even if a slurry from which the noble metal salt is removed is prepared and baked, then the noble metal is supported by the noble metal salt solution later, the same problem occurs. On the other hand, a noble metal is supported on the surface of an inorganic oxide such as alumina, silica, zirconia, and magnesia, and then a slurry is prepared by mixing an inorganic oxide, zeolite, and an inorganic binder, followed by firing.
The noble metal exists only on the surface of the inorganic oxide, and the function of the supported noble metal is sufficiently exhibited. The inorganic oxide used in the present invention is most preferably alumina. By using alumina, it becomes highly active in oxidative purification characteristics as compared with other inorganic oxides.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The alumina of the present invention has β-, γ-, δ-, θ
-, Η-, ρ-, χ-alumina and the like.

It is desirable that the content of alumina in the catalyst body of the present invention is 20 to 80% by weight. If the alumina content is less than 20% by weight, the catalytic noble metal is difficult to be highly dispersed, so that sufficient catalytic activity cannot be obtained.
%, The odor adsorption capacity of the catalyst decreases.

As the zeolite of the present invention, various zeolites can be used. Among them, the copper ion-exchanged A-type zeolite is the most excellent in the adsorption characteristics of odorous substances.

Further, silica is most excellent as an inorganic binder as a binder, and it is possible to form a film which is hard to peel off from the substrate when the catalyst is carried on the surface of the substrate without deteriorating the catalytic properties. it can.

As the noble metal of the present invention, Pt or Pd
Is preferably used, and more preferably, both Pt and Pd are used. This is because the oxidative decomposition power of Pt or Pd is higher than that of Rh or Ir, and the use of both Pt and Pd further enhances the activity. In addition, Ru
When used at high temperatures, Ru is volatilized and becomes a harmful substance.

It is desirable that the catalyst of the present invention contains cerium oxide. By including cerium oxide in the catalyst, the catalytic oxidative decomposition activity for hydrocarbon compounds can be improved.

The cerium oxide content of the present invention is desirably 2 to 15% by weight in the catalyst. When the content of cerium oxide exceeds 15 wt%, the oxidative decomposition characteristics of the catalyst begin to decrease, and when the content is less than 2 wt%, a sufficient effect of adding cerium oxide cannot be obtained.

It is desirable that the catalyst of the present invention contains barium oxide. By including barium oxide in the catalyst, the oxidative decomposition characteristics of the catalyst can be improved. The same effect can be obtained by using barium carbonate instead of barium oxide of the present invention.

The specific surface area of the catalyst of the present invention is 10 m ² /
g or more. This is because, as the specific surface area of the catalyst increases, the ratio of the far-infrared radiation amount to the amount of the emitted near-infrared ray increases, but the specific surface area is 10 m ^2.
/ G or more provides a sufficient far-infrared radiation ratio.

When coated on a substrate, the central particle diameter of the particles in the mixed slurry of the present invention is desirably 1 μm or more and 9 μm or less. When the thickness exceeds 9 μm, the coating layer becomes soft, and when the thickness is smaller than 1 μm, the coating layer is easily cracked.

The catalyst of the present invention may be formed as a coating on the surface of the substrate, molded into pellets, or wrapped in a non-woven fabric using powder.

A specific embodiment will be described below. (Example 1) After sufficiently mixing chloroplatinic acid, alumina and water using a ball mill, the mixture was calcined at 500 ° C and pulverized to prepare Pt-supported alumina. 160 g of this Pt-supported alumina and 20 wt.
% Anhydrous silicic acid colloid aqueous solution containing 400 g and water 200 g
The slurry A was prepared by sufficiently mixing 160 g of the copper ion-exchanged zeolite A with a ball mill. The average particle size of the slurry was 4.5 μm.
This slurry was coated on a cordierite honeycomb type carrier by a dip method so that the film thickness became 150 μm,
It was calcined at 500 ° C. to form a catalyst body A. The amount of the noble metal was 25 mg per 1 g of the coating layer.

This honeycomb type catalyst body A is placed behind the flame forming portion of an oil stove so that the exhaust gas of the stove passes through the catalyst, and the temperature of the catalyst during steady combustion is 300 to 500 ° C.
I tried to be. As a result, compared to those without the catalyst, even it smell weakened during even normal combustion at combustion initiation. This is because at the start of combustion, odor components are catalyzed by zeolite.
This is because the catalyst body is adsorbed by the body and is oxidized and decomposed by the noble metal during steady combustion.

A slurry B was prepared by sufficiently mixing chloroplatinic acid, alumina and an aqueous solution of colloidal silicic anhydride with water and copper ion-exchanged A-type zeolite using a ball mill. Using this slurry, a catalyst B having a noble metal supported on a copper ion-exchanged A-type zeolite or silica was similarly prepared.

Furthermore, at the time of preparing the slurry A, alumina-free precious metal-free alumina was used, and the aluminate-olyte coating layer was formed on the honeycomb-type carrier in the same manner as the catalyst body A.
The catalyst was impregnated with an aqueous chloroplatinic acid solution by a dipping method and heat-treated to prepare a catalyst C carrying the same amount of Pt as the catalyst A.

The catalyst bodies A, B and C have a diameter of 2c
m, cut into a cylindrical shape having a length of 3 cm, put it into a quartz tube having an inner diameter of 2 cm, and put 100 ppm of isovaleric acid into the quartz tube.
100 ml / min in was circulated, the catalyst body 10 ° C. / min
And the temperature dependence of the ability to purify isovaleric acid was examined.
The results are shown in (Table 1).

[0025]

[Table 1]

As is evident from Table 1, the catalyst B and the catalyst C in which the noble metal is also supported on the copper ion-exchanged A-type zeolite and silica are lower than the catalyst A in which the noble metal is supported on the alumina surface. Was active. This is presumably because the odor substance is larger than the zeolite pores and the odor substance cannot enter the pores, so that the noble metal present in the pores (about several angstroms) of the zeolite does not function effectively. Conversely, when the noble metal is present on the alumina surface, the function of the noble metal carried thereon can be sufficiently exhibited.

Example 2 Catalyst A prepared in Example 1
, A catalyst was prepared by replacing alumina in the catalyst with various inorganic oxides as shown in (Table 2).

These catalysts were cut into a column having a diameter of 2 cm and a length of 3 cm, placed in a quartz tube having an inner diameter of 2 cm, and 100 ppm of isovaleric acid of 100 ppm was placed in the quartz tube.
was circulated in l / min, the catalyst body was warmed at 10 ° C. / min, was investigated the temperature dependence of isovaleric acid purification performance. The temperature at which the conversion is 50% is shown in (Table 2).

As shown in Table 2, the use of alumina, silica, zirconia, and magnesia improved the activity as compared with the catalyst B of Example 1 in which the noble metal was also supported on zeolite. Among them, the highest activity was obtained when alumina was used.

From the above results, by supporting a noble metal on alumina, silica, zirconia, and magnesia,
The activity is higher than when noble metal is present in the pores of the zeolite. Among them, it is most desirable to use alumina.

[0031]

[Table 2]

Example 3 A catalyst was prepared by replacing the copper zeolite in the catalyst coating layer with another ion-exchanged zeolite in the catalyst A prepared in Example 1. These catalysts were tested for their ability to adsorb odorous substances at room temperature using methyl mercaptan, a typical odorant. The test method was as follows. A honeycomb-shaped catalyst body was cut into a cylindrical shape having a diameter of 2 cm and a length of 3 cm, placed in a quartz tube having an inner diameter of 2 cm, and 50 ppm of methyl mercaptan was placed in the quartz tube at 100 ml / m 2.
In circulation, the time required for methyl mercaptan to break through was determined. The results are shown in (Table 3).

As is clear from Table 3, copper ion-exchanged zeolite A has the longest time until methyl mercaptan breaks through, so that copper ion-exchanged zeolite has the best odorant adsorption ability. Is considered desirable.

[0034]

[Table 3]

Example 4 During the preparation of the slurry A of Example 1, various slurries having a center particle diameter of 0.8 μm to 15 μm were prepared by changing the milling time in a ball mill. Using this slurry, a honeycomb-type carrier was coated in the same manner as in Example 1 to form a catalyst. Next, the film hardness of the coating layer formed here was examined by a pencil hardness test according to JIS G-3320. The results are shown in (Table 4).

As is clear from Table 4, when the thickness exceeds 9 μm, the coating layer becomes soft, and when the thickness is smaller than 1 μm, the coating layer is easily cracked.

Therefore, the center particle diameter of the particles in the mixed slurry of the present invention is desirably 1 μm or more and 9 μm or less.

[0038]

[Table 4]

[0039]

As described above, in the present invention, the odor of the atmosphere in which the catalyst is placed is purified by the adsorption of zeolite, and the catalyst is heated when the adsorption capacity of zeolite reaches saturation. In addition, contacting heated air with the catalyst activates the precious metal, which is a catalytic substance, deodorizes odorous substances in the air that contacted the catalytic body, and also oxidizes odorous substances adsorbed on zeolite with the noble metal. It can decompose and regenerate the adsorption capacity of zeolite. Further, since a noble metal is supported on the surface of an inorganic oxide such as alumina, silica, zirconia, and magnesia, the catalyst function of the noble metal can be sufficiently exhibited as compared with the case where the noble metal is present in the zeolite pores.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location B01J 20/18 (72) Inventor Kyoji Yamade 1006 Kazuma, Kazuma, Kazuma, Osaka Matsushita Electric Industrial Co., Ltd. (56) References JP-A-3-213150 (JP, A) JP-A-3-47516 (JP, A) JP-A-63-7845 (JP, A) JP-A-2-56247 (JP, A A) JP-A-5-96178 (JP, A) JP-A-5-96156 (JP, A) JP-A-2-71846 (JP, A) JP-A-5-31365 (JP, A) JP-A-5 −49862 (JP, A) JP-B-58-19335 (JP, B2) JP-B-52-10438 (JP, B2) JP-B-50-9896 (JP, B2)

Claims (2)

(57) [Claims] 1. A zeolite, an inorganic binder, and
It consists of an inorganic oxide carrying a noble metal on the surface,
The oxides are alumina, silica, zirconia and magne
At least one member selected from the group consisting of
It has a function of deodorizing and deodorizing by removing and oxidizing under heating.
And a catalyst for deodorization . 2. A deodorizing catalyst body according to claim 1 Symbol placing the zeolite is a copper ion-exchange A-type zeolite.