JP3404739B2 - Filter, and air cleaner and air conditioner using the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filter, an air purifier, an air filter, which is effective in modifying harmful substances such as carbon monoxide and organic polymers contained in inks into harmless substances or useful substances. It relates to a conditioner and a humidifier.

[0002]

2. Description of the Related Art Conventionally, there has been concern about the effects of environmentally hazardous substances such as odorous substances and harmful gases on the human body and the environment.
Studies on methods for purifying and removing these environmentally hazardous substances are underway.

For example, in recent years, the airtightness of houses has been increasing, and carbon monoxide, cigarettes, etc., generated by the use of heating appliances,
Formaldehyde generated from heating appliances, furniture, building materials, household products, etc., and substances causing odors generated from refrigerators, toilets, shoes, etc. have become problems. Among them, formaldehyde is one of the causative agents of sick house syndrome with symptoms such as discomfort, tearing, sneezing, coughing, nausea and dyspnea.
In the Ministry of Health and Welfare, the standard value of indoor formaldehyde concentration is 0.1 mg / Nm ³ (80 pp
b). Therefore, the house maker and the material maker try to refrain from using the material containing formaldehyde as much as possible or to age the inside of the house after the construction and before delivering it to the owner, but this has not solved the problem fundamentally. In addition, it has been proposed to wear a mask in order to alleviate the symptoms of sick house syndrome, but when the symptoms are severe, a conventional mask has not been able to achieve a sufficient effect.

The ethylene gas contained in the air is
It is considered to be a causative substance that promotes ripening and aging of fruits and vegetables. Therefore, in order to maintain the freshness of fruits and vegetables, it is important to remove ethylene gas from the air.

By the way, in living spaces, it is important to purify and remove the above environmentally hazardous substances at room temperature. As such purifying and removing means, conventionally, adsorbents such as activated carbon and zeolite have been known, and air purifiers equipped with filters incorporating these adsorbents, air conditioners, humidifiers, etc. are widely used. ing. However, these adsorbents exert a deodorizing effect by physically adsorbing environmentally hazardous substances, and when the saturated adsorption amount is reached, a sufficient deodorizing effect cannot be obtained. Therefore, in order to obtain a sufficient deodorizing effect for a long period of time, the adsorbent must be replaced and the regeneration treatment must be frequently performed, which is not sufficient in terms of handleability and cost.

Therefore, studies on a method for reforming environmentally hazardous substances at room temperature for a long period of time are under way, and as a part of them, a method using a photocatalyst or ozone has been proposed. However, in the method using a photocatalyst, it is necessary to operate an artificial light source that is an excitation source of the photocatalyst, so the cost is high. On the other hand, in the method using ozone, in order to obtain a sufficient purification and removal effect, ozone There was a problem that the usage concentration exceeded the regulation value.

On the other hand, a catalyst for oxidizing an oxidizing substance such as carbon monoxide or trimethylamine is disclosed in Japanese Patent Application Laid-Open No. 6-21972.
1, JP-A-7-51567, JP-A-10-
Although disclosed in 296087, WO-91 / 01175, etc., it is necessary to heat to a high temperature (for example, 150 ° C. or higher) in order to carry out an oxidizing substance using these catalysts. It has not been sufficient as a means for purifying and removing harmful gas at room temperature.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems of the prior art, and is capable of sufficiently purifying and removing environmentally hazardous substances such as odorous substances and harmful gases at room temperature for a long period of time. The purpose of the present invention is to provide a filter, an air cleaner, an air conditioner, and a humidifier.

[0009]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventors have found that the above problems can be solved by using a specific catalyst in a filter, an air cleaner, an air conditioner and a humidifier. The inventors have found that they can be solved and have completed the present invention.

That is, the filter of the present invention comprises a filter body having gas permeability, an oxide carried on the filter body or contained in the filter body, in which oxygen defects are introduced by a reduction treatment, and the oxide. A catalyst comprising a noble metal supported on the oxide, wherein the oxide is cerium.
And an oxide containing zirconium , wherein the oxide has a molar ratio of cerium to oxygen of 1: 1.5 to 1:
1.8 Der is, is characterized in that used in the 50 ° C. or less.

Further, the air purifier of the present invention comprises a flow passage, through which air is introduced, having an intake port at one end and an exhaust port at the other end, and the filter of the present invention arranged in the flow channel. And a blowing unit for sequentially sending air to the intake port, the filter, and the exhaust port.

Further, the air conditioner of the present invention has a flow path for passing air, which has an intake port at one end and an exhaust port at the other end, and air in order to the intake port, the filter and the exhaust port. It is characterized in that it is provided with a blowing means for sending air and a temperature adjusting means for heating and / or cooling the air.

Furthermore, the humidifier of the present invention comprises: a flow passage for allowing air to flow, having an intake port at one end and an exhaust port at the other end; and the filter of the present invention arranged in the flow channel. ,
It is characterized by comprising a blowing unit for sequentially sending air to the intake port, the filter, and the exhaust port, and a humidifying unit for humidifying the air.

In the catalyst according to the present invention, cerium is used.
Oxygen defects are introduced into the oxide containing zirconium and zirconium, and the molar ratio of cerium to oxygen in the oxide is 1:
By setting the ratio to 1.5 to 1: 1.8, the oxide itself is activated, and the catalytic activity is enhanced by the synergistic effect of the activated oxide and the noble metal, so that it is sufficiently high at room temperature for a long period of time. Catalytic activity can be obtained. Therefore, by using the catalyst according to the present invention in a filter, an air cleaner, an air conditioner, and a humidifier, it is possible to sufficiently purify and remove environmental load substances such as odorous substances and harmful gases over a long period of time.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will now be described in detail with reference to the drawings as occasion demands.
In the drawings, the same or corresponding parts are designated by the same reference numerals.

(Catalyst) The filter, the air cleaner, the air conditioner and the humidifier of the present invention are provided with a catalyst comprising an oxide into which oxygen defects are introduced by a reduction treatment and a noble metal supported on the oxide. , Carbon monoxide, nitrogen oxides, ethylene,
It is possible to sufficiently purify and remove environmental load substances such as aldehydes, amines, mercaptans, fatty acids, and aromatic hydrocarbons at room temperature for a long period of time.
The normal temperature referred to in the present invention means a temperature at which the oxygen defects of the oxide included in the catalyst according to the present invention do not disappear, and specifically, it is 50 ° C or lower, preferably 10 to 40 ° C. In addition, an oxide into which oxygen defects are introduced refers to an oxide in which the content of oxygen atoms is lower than the value obtained based on the valence of atoms such as a transition metal or a rare earth element included in the oxide. The composition of the oxide having oxygen defects introduced therein can be determined by measuring X-ray diffraction or the like.

In the present invention, cerium and zirconium are used.
And an oxide containing both of them . Using a mixture of cerium oxide and zirconium oxide as the oxide,
There is a tendency that a higher purification and removal effect can be obtained for environmentally harmful substances such as odorous substances, carbon monoxide, nitrogen compounds, and endocrine disrupters.

[0018] In the present invention, glyceryl as oxides
Although the reason why a higher purification and removal effect for environmentally hazardous substances can be obtained by using the oxide containing cobalt and zirconium is not clear, the present inventors speculate as follows. That is, by using these oxides, the catalytic activity is enhanced by the synergistic effect of the oxide activated by the introduction of oxygen defects and the noble metal, and the presence of the oxygen defects causes the adsorption power of the environmentally hazardous substance to the noble metal. Is thought to be weakened. As a result, the purification reaction is promoted while the poisoning of the noble metal by the environmentally hazardous substance is sufficiently suppressed, and it is considered that a higher purification and removal effect can be obtained for a longer period of time.

[0019] Here, when representing the composition of the cerium oxide used in the catalyst according to the present invention in CeOx, x is 1.5 to 1.8. When x is within the above range, a higher purification and removal effect tends to be obtained particularly for formaldehyde in the air. When the cerium oxide is in the form of particles, x is 1.5 or more in the surface layer.
It is preferably 8 or less. The surface layer here means a layer from the surface to a depth of 100 nm.

When an oxide containing cerium and zirconium is used in the catalyst according to the present invention,
The oxide may be either a mixture or solid solution of cerium oxide and zirconium oxide, or a complex oxide of cerium and zirconium, but the solid solution or complex oxide facilitates the introduction of oxygen defects. preferable. Such a solid solution or complex oxide can be preferably obtained by obtaining a precipitate by a coprecipitation method using a predetermined raw material compound and firing the precipitate.

The molar ratio of cerium atom to zirconium atom in the oxide containing cerium and zirconium used in the present invention is preferably 100: 1 to 1:10.
0, more preferably 20: 1 to 1:10,
More preferably, it is 5: 1 to 1: 1. When the molar ratio between the cerium atom and the zirconium atom is within the above range, oxygen defects tend to be stably maintained. Further, it is preferable that the mixture contains more cerium atoms than zirconium atoms, because it becomes easy to introduce oxygen defects into the oxide.

In the present invention, when cerium oxide or an oxide containing cerium and zirconium is used as the oxide, an oxide of a rare earth element such as yttrium, lanthanum, neodymium, braceodymium or the like is used as another component in the oxide. Alternatively, oxides of transition metals such as iron, manganese, cobalt, chromium, nickel and copper may be further added. Above all, if at least one of yttrium oxide, lanthanum oxide, iron oxide, manganese oxide or copper oxide is added as the other component, a higher purification and removal effect on ethylene tends to be obtained.

As the noble metal used in the catalyst according to the present invention, platinum (Pt), palladium (Pd), rhodium (Rh), iridium (Ir), gold (Au), ruthenium (Ru) and the like are preferably used. To be In the present invention, one of these noble metals may be used alone or two or more of them may be used in combination. The particle size of these noble metals is preferably 5 nm or less, more preferably 1 nm or less. If the particle size of the noble metal exceeds the above upper limit, the catalytic activity tends to be insufficient. Further, the method of supporting these noble metals on the above-mentioned oxide is not particularly limited, and specific examples thereof include an impregnation method, an evaporation-drying method, a supercritical fluid method and the like.

Here, the loading amount of the noble metal according to the present invention is appropriately selected depending on the combination of the oxide and the noble metal. When the oxide containing cerium and zirconium is used as the oxide, the loading amount of the noble metal is It is preferably 0.01 to 20% by weight, more preferably 0.6 to 3.0% by weight, based on the oxide. In any case, if the supported amount of the noble metal is less than the lower limit, the catalytic activity tends to be insufficient, on the other hand, even if the supported amount of the noble metal exceeds the upper limit, the supported amount of the noble metal The effect of purifying and removing environmentally harmful substances is not obtained, and the cost tends to increase due to the use of a large amount of expensive noble metal.

In the present invention, the target catalyst having oxygen defects introduced into the oxide can be obtained by carrying out the reduction treatment after supporting the above-mentioned noble metal on the above oxide. Here, the method of the reduction treatment according to the present invention is not particularly limited, but, for example, in a reducing gas stream,
0.2 at 800 ° C (more preferably 200 to 600 ° C)
By performing the reduction treatment for 10 hours, the introduction of oxygen defects into the oxide can be performed efficiently and reliably. When the reduction treatment temperature is lower than 100 ° C., the reduction reaction becomes difficult to proceed, and the introduction of oxygen defects into the oxide tends to be insufficient. On the other hand, the reduction temperature is 800 ℃
If it exceeds, the specific surface area of the oxide tends to be small, and the catalytic activity tends to be insufficient.

Specific examples of the reducing gas used in the above reduction treatment include hydrogen, carbon monoxide, methane and formaldehyde. In the above method, the concentration of the reducing gas in the atmosphere is 0.1 to
100% by volume is preferable, 1 to 100% by volume
Is more preferable.

Furthermore, in addition to the above method, the use of a reducing agent such as hydrazine or sodium borohydride can introduce oxygen vacancies into the oxide.
In addition, in the present invention, the shape of the sample used for the reduction treatment is not particularly limited.

The specific surface area of the catalyst after the reduction treatment as described above varies depending on the conditions such as the reduction treatment temperature. For example, when an oxide containing cerium and zirconium is used, the reduction at 500 ° C. Specific surface area after treatment (B
The ET specific surface area) is preferably 50 m ² / g or more, and the specific surface area after the reduction treatment at 800 ° C. is 15 m ² / g.
The above is preferable.

The catalyst according to the present invention may be used by supporting it on titanium oxide, alumina, silica, zeolite, sepiolite, activated carbon, etc., which are conventionally known as catalyst carriers. You may use it as a mixture with these carriers. Furthermore, it is also possible to use the catalyst according to the present invention, which is carried on the above carrier and then formed into pellets, or which is held on a honeycomb-shaped or foam-shaped substrate or the like. Furthermore, a mixture of the catalyst according to the present invention and the above carrier may be formed into pellets or extruded into a honeycomb shape.

(Filter) The filter of the present invention comprises a filter body having air permeability,
The catalyst according to the present invention, which is carried on the filter main body or contained in the filter main body, and an environmental load substance contained in the air by passing air. It is possible to sufficiently purify and remove the above for a long period of time. Here, as the material of the filter body, conventionally known materials can be used, but specifically, stainless, copper, metal wool such as aluminum, cordierite, sepiolite, alumina, zeolite, activated carbon, silica, Examples include porous inorganic materials such as mullite, SiC, and mesosilica porous materials, paper, and non-woven fabric. The aperture of the filter body according to the present invention is usually 5 to 2 × 10 ⁴ μm, preferably 100 to 7 × 10 ³ μm.

The method of supporting the catalyst on the filter body is not particularly limited. For example, when a porous inorganic material is used as the filter body, the catalyst according to the present invention is added to water to form a slurry, and the porous material is added to the slurry. After immersing the inorganic material, the target filter can be obtained by sequentially performing drying, firing and reduction treatment. Here, the supported amount of the catalyst in the filter of the present invention is preferably 4 to 55% by weight based on the total amount of the filter. If the supported amount of the catalyst is less than the lower limit value, the purification / removal effect for environmentally hazardous substances tends to be insufficient, while if it exceeds the upper limit value, the filter tends to be clogged.

The filter of the present invention is suitably used for an air cleaner, an air conditioner, and a humidifier, as will be described later.

(Air Purifier) FIG. 1 is a schematic configuration diagram showing a preferred embodiment of the air purifier of the present invention. In the air cleaner shown in FIG. 1, an intake port 3 is provided at one end of a flow path 2 for passing air, and an exhaust port 4 is provided at the other end thereof. The filter 1 of the present invention is arranged between them. Further, the air purifier shown in FIG. 1 is provided with a blower unit 5 so that the air outside the air purifier can be sequentially supplied to the intake port 3, the filter 1, and the exhaust port 1.

Here, the position where the filter 1 is arranged is not particularly limited as long as the air taken into the flow path 2 from the intake port 3 can pass through the filter 1, and as shown in FIG. May be arranged at a predetermined position between the intake port 3 and the exhaust port 4, and the intake port 3 or the exhaust port 4
It may be arranged at the end of the flow path 2.

As the air blowing means 5, conventionally known ones can be used, and specific examples thereof include a fan having rotating blades.

Although not shown in FIG. 1, in the air cleaner of the present invention, the intake port 3 is provided with a rough filter (not shown) for removing dust and the like in the air. Is preferred. When the rough filter is arranged at the intake port 3, clogging of the filter 1 of the present invention is prevented, and the life of the filter tends to be longer. Examples of such a rough filter include a mesh-shaped metal filter having an opening of 100 to 10000 μm, paper, non-woven fabric and the like.

(Air Conditioner) FIG. 2 is a schematic configuration diagram showing a preferred embodiment (air conditioner for a vehicle; hereinafter referred to as a car air conditioner) of the air conditioner of the present invention. In the car air conditioner shown in FIG. 2, an intake port 3 is provided at one end of a flow path 2 for passing air, and an exhaust port 4 is provided at the other end thereof. The filter 1 of the present invention is arranged in between. The intake port 3 is composed of an intake port 3a for inside air and an intake port 3b for outside air, and the switching damper 6 can switch between the inside air and the outside air taken into the flow path 2. Further, the car air conditioner shown in FIG. 2 is provided with a blower unit 5 so that the air outside the car air conditioner can be sequentially supplied to the intake port 3, the filter 1, and the exhaust port 4. Further, a cooling means 7 and a heating means 8 as temperature adjusting means are arranged in the flow path 2, and the intake port 3
It is possible to cool and heat the air taken in from the flow path 2. The temperature inside the vehicle compartment can be adjusted by adjusting the flow rate of the air supplied to the cooling means 7 or the heating means 8 by the temperature adjustment damper (air mix damper) 9.

Here, the position where the filter 1 is arranged is not particularly limited as long as the air taken into the flow path 2 from the intake port 3 can pass through the filter 1. It may be arranged at a predetermined position between the exhaust port 4 and the end of the flow path 2 such as the intake port 3 or the exhaust port 4 as shown in FIG.

The temperature adjusting means is not particularly limited, but, for example, one having a refrigerant circulation system in which a refrigerant compressor, a condenser, an expansion mechanism and an evaporator are sequentially connected can be used. In the temperature adjusting means having such a refrigerant circulation system, the cooling means 7 and the heating means 8
Are those which utilize heat absorption or heat generation due to physical changes such as vaporization or liquefaction of a refrigerant (hydrofluorocarbon or the like).

As the air blowing means 5, any conventionally known one can be used, and specifically, a fan having rotating blades or the like can be used.

Further, although not shown in the figure, the air conditioner of the present invention may further include a dehumidifying means for removing moisture contained in the air.

Although an example of a car air conditioner is shown in FIG. 2, the air conditioner of the present invention can be suitably used for houses, aircraft, railway vehicles, ships and the like.

(Humidifier) In the humidifier of the present invention, when the air taken in from the intake port passes through the filter of the present invention, the environmentally hazardous substances contained in the air are sufficiently purified and removed at room temperature for a long period of time. It is possible to do.

In the humidifier of the present invention, the position at which the filter is arranged is not particularly limited as long as the air taken into the flow path from the intake port can pass through the filter 1. It may be arranged at a predetermined position between the port and the exhaust port, or may be arranged at the end of the flow path such as the intake port or the exhaust port.

The humidifying means according to the present invention is not particularly limited, and for example, a humidifying means provided with a container for containing water and a heater for heating the water in the container can be used. . The position of the humidifying means is not particularly limited as long as the air in the flow path can be humidified. For example, the humidifying means is arranged between the intake port and the filter, and the environment in the air after the air is humidified. The load substance may be purified and removed, or the load substance may be disposed between the filter and the exhaust port to purify and remove the environmental load substance in the air and then humidify the air.

Further, as the air blowing means in the humidifier of the present invention, conventionally known ones can be used, and specifically, a fan having rotating blades and the like can be mentioned.

[0047]

EXAMPLES The present invention will be described in more detail below with reference to production examples, examples and comparative examples, but the present invention is not limited to the following examples.

Production Example 1 Platinum-supported (cerium oxide-zirconium oxide) as a catalyst according to the present invention (hereinafter Pt /
CZ) was prepared.

First, cerium (III) nitrate 434.2
g and 53.5 g of zirconium nitrate were added to 1500 g of water to prepare an aqueous solution containing cerium atoms and zirconium atoms in a ratio of 5: 1 (molar ratio). Ammonia water was added dropwise to this aqueous solution with stirring to generate a precipitate, and then an aqueous solution containing hydrogen peroxide corresponding to ½ of the number of moles of cerium atoms contained in the aqueous solution and the resulting oxide. An aqueous solution containing alkylbenzene sulfonic acid corresponding to 10% by weight (theoretical value) was added dropwise, and the mixed solution of these was stirred to form a slurry. The slurry was dried to remove the coexisting ammonium nitrate to obtain a solid solution of cerium oxide-zirconium oxide.

Next, 150 g of the cerium oxide-zirconium oxide solid solution was impregnated with a nitric acid aqueous solution of dinitrodiammine platinum (platinum content: 2 g), dried, and calcined at 500 ° C. for 3 hours to obtain Pt / CZ (platinum loading: 1.3% by weight) was obtained.

Production Example 2 Platinum-supported cerium oxide (Pt / CeO ₂ ) was produced in the same manner as in Production Example 1 except that cerium oxide (CeO ₂ ) was used instead of the solid solution of cerium oxide-zirconium oxide in Production Example 1. Was prepared.

Production Example 3 Platinum-supported iron oxide (Pt / Fe) was produced in the same manner as in Production Example 1 except that iron oxide (Fe ₂ O ₃ ) was used instead of the solid solution of cerium oxide-zirconium oxide in Production Example 1. ₂
O ₃ ) was prepared.

Production Example 4 Platinum-supported manganese oxide (Pt / MnO ₂ ) was produced in the same manner as in Production Example 1 except that manganese oxide (MnO ₂ ) was used instead of the cerium oxide-zirconium oxide solid solution in Production Example 1. Was prepared.

Production Example 5 Platinum-supported silica (Pt / SiO ₂ ) was prepared in the same manner as in Production Example 1 except that silica (SiO ₂ ) was used in place of the solid solution of cerium oxide-zirconium oxide in Production Example 1.
₂ ) was prepared.

Production Example 6 Platinum-supported silica (P) was prepared in the same manner as in Production Example 1 except that γ-alumina (γ-Al ₂ O ₃ ) was used in place of the solid solution of cerium oxide-zirconium oxide in Production Example 1.
t / γ-Al ₂ O ₃ ) was prepared.

(Catalyst activity evaluation test 1) 20 g of the catalyst obtained in Production Example 1 was used in a mixed gas atmosphere of carbon monoxide and nitrogen (carbon monoxide content: 1% by volume).
After reduction treatment at 500 ° C. for 15 minutes, using a fixed bed flow reactor, the following conditions: Reaction gas: mixed gas of carbon monoxide (20 ppm), oxygen (20% by volume) and nitrogen Reaction gas flow rate: 5 l / Min W / F (W: catalyst weight [g], F: reaction gas flow rate [ml]
/ S]): 0.24 g · s · ml ⁻¹ Reaction temperature: An oxidation reaction of carbon monoxide was performed at 25 ° C., and the conversion rate of carbon monoxide was measured. The result is shown in FIG. In addition, in FIG. 3, as a comparative test example, the catalyst obtained in Production Example 1 was subjected to an oxidation treatment at 500 ° C. for 15 minutes in an atmosphere of a mixed gas of oxygen and nitrogen (oxygen content: 20% by volume). The reaction temperatures are 25 ° C, 50 ° C, 80 ° C, 100 ° C, 125 ° C,
The conversion rate of carbon monoxide when set at 150 ° C. is also shown.

As shown in FIG. 3, it was confirmed that carbon monoxide could be sufficiently purified and removed at room temperature when a catalyst in which oxygen defects were introduced into the oxide by the reduction treatment was used. On the other hand, when the oxidation-treated catalyst was used, the conversion rate of carbon monoxide increased with the increase of the reaction temperature, but the reaction was conducted at room temperature using the reduction-treated catalyst. The conversion rate was lower than that in the case of carrying out.

(Catalyst activity evaluation test 2) 20 g of each of the catalysts obtained in Production Examples 1 and 5 was heated at 500 ° C. in a mixed gas atmosphere of carbon monoxide and nitrogen (carbon monoxide content: 1% by volume). After reduction treatment for 15 minutes, the following conditions were obtained using a fixed bed flow reactor: Reaction gas: mixed gas of carbon monoxide (20 ppm), oxygen (20% by volume) and nitrogen Reaction gas flow rate: 5 l / min W / F: 0.24 g · s · ml ⁻¹ Reaction temperature: An oxidation reaction of carbon monoxide was performed at 25 ° C., and the conversion rate of carbon monoxide was measured. The result is shown in FIG.

As shown in FIG. 4, it was confirmed that carbon monoxide could be sufficiently purified and removed at room temperature when the catalysts obtained in Production Examples 1 and 5 were used. In particular, Production Example 1
When the catalyst obtained in 1. was used, a sufficiently high catalytic activity could be obtained for a longer period of time.

(Catalyst activity evaluation test 3) 500 g of each of the catalysts obtained in Production Examples 1 to 4 and 6 was mixed in a mixed gas of carbon monoxide and nitrogen (carbon monoxide content: 1% by volume) for 500 times. After reduction treatment at 15 ° C. for 15 minutes, the following conditions were measured using a fixed bed flow reactor: Reaction gas: mixed gas of carbon monoxide (20 ppm), oxygen (20% by volume) and nitrogen Reaction gas flow rate: 10 l / Min W / F: 0.03 g · s · ml ⁻¹ Reaction temperature: An oxidation reaction of carbon monoxide was performed at 25 ° C., and the conversion rate of carbon monoxide was measured. The result is shown in FIG.

As shown in FIG. 5, it was confirmed that carbon monoxide could be sufficiently purified and removed at room temperature when any of the catalysts obtained in Production Examples 1 to 4 and 6 was used. In particular, when the catalysts obtained in Production Examples 1, 2, and 4 were used, a sufficiently high catalytic activity could be obtained for a longer period of time.

(Catalyst Activity Evaluation Test 4) 5 g of the catalyst obtained in Production Example 1 was mixed with 1 g of carbon monoxide and nitrogen in a mixed gas (carbon monoxide content: 1% by volume) atmosphere.
Reduction treatment was performed for 15 minutes at a predetermined temperature within the range of 50 to 600 ° C. to prepare catalysts having different oxygen deficiency amounts. For each of the catalysts thus obtained, the following conditions were determined using a fixed bed flow reactor: Reaction gas: mixed gas of carbon monoxide (20 ppm), oxygen (20% by volume) and nitrogen Reaction gas flow rate : 10 l / min W / F: 0.03 g · s · ml ⁻¹ Reaction temperature: An oxidation reaction of carbon monoxide was performed at 25 ° C., and the conversion rate of carbon monoxide was measured. The result is shown in FIG. The amount of oxygen vacancies in each catalyst was determined by measuring the composition (Ce
₅ ZrO _x ; x represents a number of 12 or less) and was calculated using the following formula: (oxygen defect amount) = (12−x) / 12.

As shown in FIG. 6, it can be seen that the conversion rate of carbon monoxide increases as the amount of oxygen defects increases.

(Catalyst Activity Evaluation Test 5) 2 g of each of the catalysts obtained in Production Examples 1 and 2 was subjected to 500 atmosphere in a mixed gas of hydrogen and nitrogen (hydrogen content: 5% by volume).
After reduction treatment at 1 ° C for 1 hour, the following conditions were used using a fixed bed flow reactor: reaction gas: formaldehyde (100 ppb), oxygen (20% by volume) and nitrogen mixed gas Reaction gas flow rate: 10 l / min W / F: 2 × 10 ⁻³ g · s · ml ⁻¹ Reaction temperature: An oxidation reaction of formaldehyde was performed at 25 ° C., and the conversion of formaldehyde was measured. The result is shown in FIG. 7. In addition,
FIG. 7 also shows the conversion rate of formaldehyde when using activated carbon as a comparative test example.

As shown in FIG. 7, it was confirmed that when the catalysts obtained in Production Examples 1 and 2 were used, carbon monoxide could be sufficiently purified and removed at room temperature.

(Catalytic activity evaluation test 6) 0.1 g of the catalyst obtained in Production Example 1 was subjected to reduction treatment at 500 ° C. for 1 hour in a mixed gas atmosphere of hydrogen and nitrogen (hydrogen content: 5% by volume). Then, the mixture was placed in a closed container, and 5 L of a mixed gas of acetaldehyde (80 ppm), oxygen (20% by volume) and nitrogen was introduced into the closed container. After a lapse of a predetermined time, the gas was weighed from the container with a microsyringe, and the concentrations of acetaldehyde and carbon dioxide in the gas were quantified by gas chromatography (FID). FIG. 8 shows the correlation between the acetaldehyde concentration and the reaction time obtained by the above test, and FIG. 9 shows the correlation between the carbon dioxide concentration and the reaction time.
Shown respectively. 8 and 9 also show the results when activated carbon was used as a comparative test example.

As shown in FIGS. 8 and 9, when the catalyst obtained in Production Example 1 was used, the reforming of acetaldehyde to carbon dioxide could be sufficiently carried out at room temperature.

Example 1 A slurry was prepared by mixing 100 g of the catalyst obtained in Production Example 1, 35 g of alumina sol (Nissan Chemical Co., Ltd.) and 20 ml of distilled water. A 300-cell cordierite carrier (manufactured by Nippon Glass Co., Ltd., outer size: 100 mm ×)
(Corresponding to 100 mm × 10 mm), the cordierite carrier is taken out of the slurry, excess slurry is removed, dried at 120 ° C. for 3 hours, calcined at 450 ° C. for 2 hours in an air stream, and further hydrogen and nitrogen are added. In a mixed gas of (hydrogen content: 5% by volume), reduction treatment was performed at 500 ° C. for 1 hour to obtain a target filter.

Next, the above filter was attached to the air purifier having the structure shown in FIG. 1, and the air purifier was installed in a 6-tatami mat room two years after construction by the conventional wooden construction method. Operate this air purifier at a linear velocity of 1.2m / sec for the air flow,
The time-dependent change of the formaldehyde concentration in the air discharged from the exhaust port was measured. The results are shown in Table 1. A Kitagawa gas detector (manufactured by Gaskuro Industry Co., Ltd.) was used to measure the formaldehyde concentration.

Comparative Example 1 Formaldehyde in the air discharged from the exhaust port of the air purifier was prepared in the same manner as in Example 1 except that the filter of Example 1 was replaced by a filter consisting of a cordierite carrier alone. The change in concentration with time was measured. The results are shown in Table 1.

Comparative Example 2 A filter was produced in the same manner as in Example 1 except that the catalyst obtained in Production Example 1 was supported on a cordierite support and no reduction treatment was carried out. In the same manner as in Example 1 except that the filter thus obtained was used,
The change with time of the formaldehyde concentration in the air discharged from the exhaust port of the air purifier was measured. The results are shown in Table 1.

[0072]

[Table 1]

As shown in Table 1, it was confirmed that formaldehyde could be sufficiently purified and removed at room temperature when the air cleaner of Example 1 was used. On the other hand, Comparative Example 1
When the air cleaners of Nos. 2 and 2 were used, a sufficient formaldehyde purifying / removing effect was not recognized even after 8 hours from the start of operation.

Example 2 The filter after the reduction treatment obtained in Example 1 was mounted on a car air conditioner having the structure shown in FIG. This car air conditioner is a sedan type gasoline engine car (total displacement:
1300cc, mileage: 25337km),
Regarding air released from the exhaust port after operating at 23 ° C for 1 hour, the pleasantness and discomfort and odor intensity were evaluated by sensory evaluation tests, and the odor concentration was determined by the three-point comparison odor bag method. Qualitative / quantitative analysis of was carried out by gas chromatography-mass spectrometry (GC-MS method). Table 2 shows the results immediately after operating the car air conditioner and after operating for 1 hour. In addition, the degree of pleasantness and discomfort is as follows: +4: Extremely pleasant +3: Very pleasant +2: Pleasant + 1: Fairly pleasant 0: Neither pleasant nor unpleasing -1: Slightly unpleasing -2: Displeasing -3: Very unpleasant -4: Based on extremely unpleasantness, and the odor intensity has the following criteria: 0: Odorless 1: Odor that can be finally detected (detection threshold concentration) 2: Weak odor that identifies what odor (cognitive threshold concentration) 3: Easily detectable odor 4: Strong odor 5: Strong odor was evaluated based on each.

[0075]

[Table 2]

As shown in Table 2, it was confirmed that when the car air conditioner of Example 2 was used, odorous substances could be sufficiently purified and removed at room temperature.

[0077]

As described above, the filter of the present invention,
The air purifier, air conditioner, and humidifier make it possible to sufficiently purify and remove environmentally hazardous substances such as odorous substances and harmful gases at room temperature for a long period of time.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a preferred embodiment of an air cleaner of the present invention.

FIG. 2 is a schematic configuration diagram showing a preferred embodiment (car air conditioner) of the air conditioner of the present invention.

FIG. 3 is a graph showing the correlation between the conversion rate of carbon monoxide and the reaction temperature, which was obtained in the catalytic activity evaluation test 1 in the examples.

FIG. 4 is a graph showing the correlation between the conversion rate of carbon monoxide and the reaction time, which was obtained in the catalytic activity evaluation test 2 in the examples.

FIG. 5 is a graph showing the correlation between the conversion rate of carbon monoxide and the reaction time, which was obtained in the catalytic activity evaluation test 3 in the examples.

FIG. 6 is a graph showing the correlation between the conversion rate of carbon monoxide and the amount of oxygen defects, which is obtained in the catalyst activity evaluation test 4 in the examples.

FIG. 7 is a graph showing a correlation between a conversion rate of formaldehyde and a reaction time, which was obtained in a catalytic activity evaluation test 5 in Examples.

FIG. 8 is a graph showing the correlation between the acetaldehyde concentration and the reaction time, which was obtained in the catalytic activity evaluation test 6 in the examples.

FIG. 9 is a graph showing the correlation between carbon dioxide concentration and reaction time, which was obtained in a catalyst activity evaluation test 6 in Examples.

[Explanation of symbols]

1 ... Filter, 2 ... Flow path, 3 ... Intake port, 3a ... Inside air intake port, 3b ... Outside air intake port, 4 ... Exhaust port, 5 ... Blower means, 6 ... Switching damper, 7 ... Cooling means, 8 ... Heating means, 9
… Temperature control damper.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI B01J 23/63 B01D 53/36 ZABH F24F 1/00 F24F 1/00 371Z 7/00 B01J 23/56 301A (72) Inventor Sasaki Civic Aichi Prefecture, Nagakute-machi, Aichi-gun, Nagatoko, 41, Yokochi Central Research Institute, Inc. (72) Inventor, Akira Morikawa, Aichi-gun, Nagakute-cho, Aichi, 1-Cho, Yokota, Central Research Institute, Toyota Central Research Institute (72) ) Inventor Hiroaki Hayashi 1 41, Nagachote, Nagakute-cho, Aichi-gun, Aichi Prefecture 1st in Yokota Central Research Institute Co., Ltd. (72) Inventor Masaaki Sugiura 1 41, Yokochi-cho, Nagakute-cho, Aichi-gun, Aichi Prefecture 1 Toyota, Ltd. Central Research Laboratory (56) Reference JP-A-10-258234 (JP, A) JP-A-10-277394 (JP, A) JP-A-10-296087 (J (P, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) B01D 53/86 B01J 21/00-38/74

Claims (4)

(57) [Claims] 1. A filter body having air permeability, an oxide having oxygen defects introduced by a reduction treatment, which is supported on the filter body or contained in the filter body, and a noble metal supported on the oxide. And a catalyst comprising, wherein the oxide contains cerium and zirconium
Are those, the molar ratio of cerium and oxygen in the oxide is 1: 1.5 to 1: 1.8 der is, used at 50 ° C. or less of
A filter characterized by being 2. A flow path for passing air, which has an intake port at one end and an exhaust port at the other end, the filter according to claim 1 disposed in the flow path, and the air intake port. An air purifier for sequentially sending air to the filter and the exhaust port. 3. A flow path for passing air, which has an intake port at one end and an exhaust port at the other end, the filter according to claim 1 disposed in the flow path, and the air intake port. An air conditioner comprising: an air blowing unit for sequentially sending the air to the filter and the exhaust port; and a temperature adjusting unit for heating and / or cooling the air. 4. A flow path for passing air, which has an intake port at one end and an exhaust port at the other end, the filter according to claim 1 disposed in the flow path, and the air intake port. A humidifier, comprising: a blowing unit for sequentially sending the air to the filter and the exhaust port; and a humidifying unit for humidifying the air.