JPH05131138A - Deodorizing catalyst body - Google Patents

Abstract

PURPOSE:To provide a catalyst body capable of performing the deororizing/ oxidative decomposition of a malodorous component at room temp., enhanced in the adhesion of a catalystic component and having a large specific surface area. CONSTITUTION:A deodorizing catalyst body is constituted of a catalyst sheet 2 consisting of a ceramic fiber, the zeolite fine powder supported on the surface and interstices of the fiber and oxides of gold and iron in an amount effective for deodorizing (gold content; 0.2-0.9g/l, iron content; 0.3-1.5% by wt. of the catalyst body) and provided with many ventilation holes 2 by molding the sheet 2 into a honeycomb shape. The zeolite fine powder and oxides of gold and iron are arranged even in the gaps of the reticulated structure of the ceramic fiber and the highly active catalyst body suitable for deodorizing having a large active surface area and enhanced in the adhesion of a catalytic component is obtained without requiring a complicated process.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalyst body for oxidizing and decomposing malodorous components such as ammonia and various amines, and more particularly to a deodorizing catalyst body excellent in oxidation reaction at room temperature.

[0002]

2. Description of the Related Art As a deodorant touch agent for purifying a bad odor, an adsorbent mainly composed of physical adsorption represented by activated carbon is the mainstream, and there is almost no deodorant which can be recycled.

On the other hand, as industrial deodorizing means, various catalysts for catalytically oxidizing malodorous components have been put into practical use.
The oxidation catalyst can be reused because it decomposes malodorous components by the oxidation reaction to make them odorless, but it requires a temperature of at least 200 ° C or higher to obtain catalytic activity and requires heating means, so it is in the normal temperature range. There is a desire for a low temperature active catalyst that can be used in.

As a low-temperature active catalyst that meets such demands, a hopcalit catalyst mainly containing manganese oxide and copper oxide has been put into practical use, but the low-temperature activity of the hopcalit catalyst rapidly decreases due to moisture. It has fatal drawbacks and is not suitable for decomposing odors such as ammonia and amines.

On the other hand, in recent years, a highly dispersed gold-supported catalyst composed of iron oxide and gold has been proposed, and a good combustion rate of carbon monoxide has been obtained even in a low temperature range of -30 ° C. 60-238148). Also, a carrier such as alumina, silica, zeolite, or titania carrying 20% by weight or more of a metal oxide such as iron oxide is put in an alkaline solution having a pH of 7.5 or more while keeping the pH at 7.5 to 9.5. A method has been proposed in which a gold compound solution such as chloroauric acid is added to deposit and support gold in an amount of 0.1 to 20 g / l catalyst to obtain a catalyst precursor, and then calcination is performed. This makes it possible to obtain a catalyst having a high activity equivalent to that of a gold-metal oxide catalyst which does not use a carrier even when the seed metal compound is supported on the carrier with respect to the carbon monoxide burning rate (special characteristics). Kaihei 1-94945).

[0006]

In such a gold-metal oxide catalyst, optimum catalyst preparation conditions, that is, optimum amounts of gold and iron metal oxides, exist depending on the gas component to be oxidized. It is necessary to design an optimum catalyst for the deodorization / oxidative decomposition of malodorous components such as ammonia and various amines.

Further, when the gold-metal oxide catalyst is supported on a carrier made of an inorganic material, the adhesion may be lowered depending on the supporting method and the active component may be easily desorbed.
The catalyst is expensive because it requires relatively complicated steps and equipment like the method disclosed in Japanese Patent No. 4945.

The present invention is intended to solve the above problems,
To provide a catalyst body suitable for deodorizing ammonia, various amines, etc. in an oxidation catalyst containing gold, iron oxide and zeolite as a catalyst component, and to obtain a catalyst body having high adhesion of the catalyst component and a large specific surface area. It is an object.

[0009]

In order to achieve the above object, the oxidation catalyst body of the present invention comprises a ceramic fiber, a zeolite supported on the surface of the ceramic fiber and in a gap between the ceramic fibers, a metal of gold and iron. It is composed of an oxide, and the content of the gold is 0.2 to 0.9 g / l (catalyst volume),
Further, the content of iron is set in the range of 0.3 to 1.5% by weight based on the weight of the catalyst body.

[0010]

The oxidation catalyst body of the present invention is arranged in a normal temperature air stream containing a malodorous component such as ammonia and various amines, and is generally used in an air circulation system using a blower fan or the like. When the air containing the malodorous component passes through the catalyst body, the malodorous component is selectively adsorbed on the zeolite surface having a large adsorption surface area, and the odor is alleviated and released. The adsorbed malodorous component is activated by the interaction of metal ions composed of gold and iron and the action of the solid acid of zeolite, and an oxidative decomposition reaction occurs in a normal temperature atmosphere. Let go. As a result, the adsorption site is regenerated and new malodorous molecules can be adsorbed. The reaction speed at this time is relatively slow, and the malodorous component is once adsorbed and then gradually reacted.
Therefore, it is suitable for relatively low concentration deodorization, and more suitable for intermittent deodorization rather than continuous deodorization. That is, after deodorizing for a predetermined time, it is necessary to stand in the presence of oxygen for a predetermined time for oxidative decomposition.

The performance required for this type of deodorizing catalyst is that it can efficiently deodorize when an odor component passes, that is, it has a strong adsorption power for the odor component and decomposes the adsorbed odor component efficiently. That is, the oxidation activity is high. In the present invention, in the combination of ceramic fiber, zeolite, gold, and iron oxide, the gold content is 0.2 to 0.9 g / l (catalyst volume), and the iron content is the catalyst weight. On the other hand, it has been found that the above performance can be most effectively exhibited by setting the content to 0.3 to 1.5% by weight.

Further, in the present invention, since the ceramic fiber constitutes the skeleton of the catalyst body, it has a porous structure, and the fine zeolite powder and metal oxides of gold and iron are not limited to the surface of the catalyst body but the ceramic fiber. It will also exist in the gap of several tens of μm. As a result, the specific surface area can be increased and the catalytically active surface area is expanded. This is suitable for this type of deodorizing catalyst, that is, a catalyst in which a malodorous component is once adsorbed and then oxidatively decomposed.

Further, the metal oxides of gold and iron, which are the catalyst components, and the zeolite fine powder are arranged in the gaps of the network structure of the ceramic fibers, so that the adhesion is improved and the active component is less likely to be desorbed. As a result, it becomes possible to carry the catalyst with high adhesion without performing a complicated carrying operation, and since the skeleton is made of ceramic fibers, the brittle resistance strength is improved.

As described above, according to the present invention, a catalyst body is composed of zeolite fine powder which is a catalyst component, metal oxides of gold and iron, and ceramic fibers, and the main active components of gold and iron are contained. By providing a deodorizing catalyst body capable of oxidizing and decomposing malodorous components such as ammonia and amines at room temperature by limiting the amount to a predetermined range, it is possible to use as a filter for deodorizing or air purifying without catalyst heating means. It is of high practical value.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in more detail with reference to the accompanying drawings.

FIG. 1 is a perspective view showing the appearance of an oxidation catalyst body according to the present invention, in which 1 is a catalyst body, 2 is a ceramic fiber such as silica and alumina, and the surface of the ceramic fiber and a gap between the ceramic fibers. It is a catalyst sheet composed of supported zeolite and metal oxides of gold and iron. Here, the content of gold is 0.2 to 0.9 g / l (catalyst volume), and the content of iron is 0.3 to the weight of the catalyst.
It is prepared to be in the range of 1.5% by weight. If necessary, an inorganic binder may be added to improve the bond between the ceramic fiber and the metal oxide composed of zeolite, gold, and iron. The catalyst sheet 2 is laminated or wound by a method described below and formed into a honeycomb shape, and a plurality of vent holes 3 are formed in order to reduce pressure loss when a bad odor passes through.

Next, a specific embodiment of the above structure will be described. Example 1 Ceramic fiber composed of silica and alumina, and pore size 1
An organic binder was mixed with 0Å NaX-type zeolite fine powder, and a solvent was further added to prepare a mixed slurry having an appropriate viscosity, and a ceramic sheet was prepared by a papermaking method. This ceramic sheet that has been pre-dried at a predetermined temperature is corrugated by a corrugator, and the corrugated ceramic sheet and those that are not corrugated are bonded using an inorganic binder. After being molded into a compact, it was fired at about 350 ° C. to obtain a composite carrier of ceramic fiber and zeolite. After that, an aqueous solution was prepared by adding a solvent to chloroauric acid and iron nitrate at a predetermined ratio, and the aqueous solution was carried on the composite carrier by an impregnation method. At this time, since the zeolite present on the composite carrier has a property of strongly adsorbing water having a large dipole moment, it is strongly impregnated with an acidic aqueous solution of chloroauric acid and iron nitrate, and The metal oxides of gold and iron can be efficiently supported with good dispersibility even in the internal voids of the network structure. After the loading operation, it is dried at a temperature around 100 ° C.
A deodorizing catalyst body was obtained by firing in air at 0 ° C. for 10 minutes. Using the above-mentioned preparation method, catalysts having different contents of gold and iron were prepared by changing the adjustment ratio of chloroauric acid and iron nitrate, and a deodorizing purification test and an odor component desorption test were carried out under the following test conditions. ..

Test condition 1 (deodorization purification test) Gas used: trimethylamine (CH ₃ ) ₃ N (nitrogen balance) A concentration of 100 PPM was mixed with air in the atmosphere to obtain 50 PPM.
Used after diluting to the concentration.

Space velocity: 12000 / h Measuring device: Gas chromatography measuring device; Fixed flow reactor temperature: Room temperature Test condition 2 (odor component elimination test) After the measurement under test condition 1 is completed, the catalyst is not adsorbed. The sample is inserted into a container of No. 1, sealed with 10 l of air and left at room temperature, and the atmospheric concentration of trimethylamine is measured every predetermined time.

Measuring instrument: gas chromatography temperature: room temperature Test results of catalyst bodies having different gold and iron contents under the above test conditions, that is, the supported amount of gold and the adsorption rate Ra and desorption of trimethylamine (hereinafter referred to as TMA). Rate Rr
The relationship is shown in FIG. Here, the adsorption rate Ra is, when the test gas is passed for 2 hours under the test condition 1, the supplied mass of TMA on the inlet side is mi, and the mass of TMA detected on the outlet side is m.
If o, it was calculated by (Equation 1).

[0021]

[Equation 1]

The desorption rate Rr is the mass of TMA adsorbed on the catalyst body under test condition 1, that is, the amount obtained by subtracting mo from mi is defined as mc, and the desorption rate of TMA desorbed from the catalyst body into the non-adsorbate container is When the mass is mr, it was calculated by (Equation 2).

[0023]

[Equation 2]

That is, the higher the adsorption rate Ra, the better the deodorizing and purifying performance, and the desorption rate Rr indicates the rate at which the adsorbed TMA is desorbed as it is. It is a measure that the rate of conversion to the component of is high. Note that in FIG. 2, the amount of supported gold is 0, and an example of a catalyst body that does not support gold and iron as main catalysts is shown for comparison. From the figure, the adsorption rate Ra is
It can be seen that the amount of supported gold tends to decrease as the supported amount of gold increases, and that the desorption rate Rr has a minimum peak around the supported amount of gold of 0.5 g / l. The catalyst shown as a comparative example has good adsorption characteristics, but 75% of the amount of TMA adsorbed is desorbed.

From the result of FIG. 2, the allowable limit of the desorption rate Rr is set to 4
When the content is 0% or less, the amount of gold supported is 0.2 g / l to 0.9 g /
There is an optimal range for l. The iron content at this time was 0.3% by weight to 1.5% by weight based on the weight of the catalyst body.

The desorption rate Rr of 40% or less is a permissible limit value at a level at which odor is not a problem when actually used in the case of assuming a domestic flush toilet as the deodorization catalyst body. Is.

Example 2 Ceramic fiber made of silica and alumina, and Na
Mixing a fine powder of X-type zeolite with an organic binder,
Further, a solvent was added to prepare a mixed slurry adjusted to an appropriate viscosity, and gold was added by the same preparation method as in Example 1 above.
Catalyst bodies impregnated with g / l (catalyst volume) and iron content of 1.8% by weight based on the weight of the catalyst body were prepared by changing the calcination temperature and varying the calcination conditions. ,
The results of the deodorization purification test and the odor component desorption test conducted under the same test conditions as in Example 1 are shown in FIG.

The adsorption rate Ra increased and the desorption rate Rr tended to decrease as the firing temperature decreased. From this, it can be said that the lower baking temperature is suitable for deodorizing TMA. When the temperature is 200 ° C. or lower, chloride and nitrate components in the adjusted liquid may remain, and when the temperature is 400 ° C. or higher, the crystal structure of NaX type zeolite may be destroyed. Therefore, the desorption rate R is the same as in Example 1 above.
When r is 40% or less, the optimum firing temperature range is 20
Present at 0-350 ° C.

[0029]

As described above, according to the present invention, the fine zeolite powder as the catalyst component and the metal oxides of gold and iron within the range effective for deodorizing the malodorous component are added to the surface of the ceramic fiber and the ceramic. The present invention provides an oxidation catalyst body supported in the gaps between fibers and suitable for deodorization, and the following effects can be obtained. (1) Since the contents of gold and iron, which are the main active components of the catalyst, are set to an amount effective for deodorization, it is possible to effectively deodorize / oxidize and decompose odorous components such as ammonia and amines at room temperature and to deodorize for a long life A catalyst body is provided, and a deodorizing device or an air cleaning filter that does not require catalyst heating means can be realized. (2) Since the ceramic fiber constitutes the skeleton of the catalyst body, it has a porous structure, and the zeolite fine powder and metal oxides of gold and iron are not only on the surface of the catalyst body, but are several tens of μm between the ceramic fibers. Exists also in the voids, and the specific surface area can be increased, and the catalytically active surface area and adsorption surface area can be increased. (3) Since the metal oxides of gold and iron, which are the catalyst components, and the zeolite fine powder are arranged in the gaps of the network structure of the ceramic fibers, the adhesion is improved and the active component is less likely to be desorbed.
As a result, it becomes possible to carry the catalyst with high adhesion without performing a complicated carrying operation, and since the skeleton is made of ceramic fibers, the brittle resistance strength is improved.

[Brief description of drawings]

FIG. 1 is an external perspective view of a deodorizing catalyst body according to an embodiment of the present invention.

FIG. 2 Adsorption and desorption characteristic diagram of deodorizing catalyst

FIG. 3 is a characteristic diagram of adsorption and desorption of a deodorizing catalyst body showing another embodiment of the present invention.

[Explanation of symbols]

 1 catalyst body 2 catalyst sheet 3 vent hole

Claims (2)

[Claims] 1. A ceramic fiber, a zeolite supported on a surface of the ceramic fiber and in a gap between the ceramic fibers, and a metal oxide of gold and iron, wherein the content of the gold is 0.2 to 0.9 g /. 1 (catalyst body volume), and the deodorizing catalyst body in which the iron content is 0.3 to 1.5% by weight based on the weight of the catalyst body. 2. A catalyst precursor in an air atmosphere of 200-35.
The deodorizing catalyst body according to claim 1, which is calcined in a temperature range of 0 ° C.