JP2004216255A - Deodorization element, manufacturing method therefor, and refrigeration cycle apparatus using deodorization element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a deodorization element efficiently carrying out a decomposition reaction of a photocatalyst, applicable for various odor gases exhibiting acidic property and a basic property, shortening an irradiation time for the photocatalyst material and sufficiently retaining the deodorization effect for a long time period, a manufacturing method therefor and a refrigeration cycle apparatus using the deodorization element. <P>SOLUTION: The deodorization element comprises a base material 1 having a honeycomb shape and a deodorization material layer provided on the base material 1. The deodorization material layer comprises a metal oxide 3 and the photocatalyst 4. The metal oxide 3 is formed by coating the base material 1 with a dispersion comprising a metal hydroxide and a liquid component and by heating it. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
TECHNICAL FIELD The present invention relates to a deodorizing element useful for removing odorous substances from air, a method for producing the same, and a refrigeration cycle apparatus using the deodorizing element.
[0002]
[Prior art]
Odorous substances emitting foul odors are generated from various sources, for example, everyday living environments, facilities such as factories, human waste treatment plants, and garbage disposal plants, and pose a problem as a cause of bad odor pollution. Examples of the odorants include ammonia, nitrogen-containing compounds such as amines (such as trimethylamine and triethylamine), hydrogen sulfide, sulfur-containing compounds such as mercaptans (such as methyl mercaptan), aldehydes (such as formaldehyde and acetaldehyde), and lower fatty acids. Many compounds are known, such as (formic acid, acetic acid, valeric acid, etc.).
[0003]
Activated carbon is widely used for deodorizing such odorous substances. However, activated carbon has a small adsorption capacity for nitrogen-containing compounds such as ammonia and sulfur-containing compounds such as hydrogen sulfide. Further, there is a problem that various odorous substances cannot be adsorbed even when only activated carbon is used. Therefore, an adsorbent in which activated carbon carries a halogen compound, a metal ion, an acid, an alkali, and the like has been proposed. However, even if these adsorbents are used, they have not yet achieved sufficient deodorizing ability.
In addition, zeolite, silica gel, activated alumina and the like are also used as deodorizing elements. However, they have a low adsorption capacity for odorous substances, and the equilibrium adsorption concentration, which is an index of the deodorization ability, increases with an increase in the amount of adsorption, so that the odor removal becomes insufficient with the elapse of the treatment time.
[0004]
In order to improve the limit of the deodorizing ability, there is a deodorizing method using a photocatalyst such as titanium oxide. In this method, the odorous substance adsorbed on the photocatalyst surface is oxidized and decomposed by irradiation with light such as ultraviolet rays. Therefore, as long as the photocatalyst has a sufficient reaction surface and continues irradiation with light, it has a high processing ability. However, in the deodorizing treatment method using a photocatalyst, when the light irradiation is not performed, the odorous substance is not oxidized and decomposed. That is, if the photocatalyst is not always irradiated with light, a deodorizing effect cannot be expected.
Then, as a deodorizing element which improves such a problem, there is an element obtained by sintering a mixture of an adsorbent and a photocatalyst (for example, see Patent Document 1).
[0005]
[Patent Document 1]
Japanese Patent No. 2138415 (Claim 1)
[0006]
[Problems to be solved by the invention]
However, the deodorizing element specifically proposed uses titanium oxide which is an acidic solid catalyst as a photocatalyst, and the adsorbent such as zeolite and silica used together has an acidic solid surface. In other words, although the deodorizing element using the photocatalyst is excellent in the adsorptivity to the basic substance, it has a problem that it is difficult to expect the active adsorption and removal of the acidic substance. Adsorbents made of alumina are expected to adsorb acidic substances, but alumina has a lower electronegativity than silica or titanium oxide, and the material itself increases as the ratio of alumina in the deodorizing element increases. Is increased in hydrophilicity. Then, the amount of moisture adsorbed by the deodorizing element increases, and there is a problem that the amount of adsorbing odorous substances that must be adsorbed decreases.
[0007]
Therefore, when the above-mentioned deodorizing element is mounted on various refrigeration cycle devices such as air conditioners and refrigerators, the performance of the deodorizing element is reduced by long-term use, or an odorous substance that cannot be completely adsorbed causes further odor. Or problems.
[0008]
An object of the present invention is to effectively perform a decomposition reaction of an odorous substance by a photocatalyst in order to solve the above-described problems. The present invention also provides a deodorizing element having good deodorizing properties for both odorous substances such as acidic substances (eg, methyl mercaptan, dimethyl sulfide, etc.) and basic substances (eg, ammonia, trimethylamine, etc.). Aim. Still another object of the present invention is to provide a refrigeration cycle apparatus using a deodorizing element capable of maintaining a deodorizing effect for a long period of time.
[0009]
[Means for Solving the Problems]
The present invention comprises a substrate having a honeycomb shape and a deodorizing material layer provided on the substrate, wherein the deodorizing material layer comprises a metal oxide and a photocatalyst, wherein the metal oxide is a metal hydroxide and Provided is a deodorizing element which is formed by applying a dispersion composed of a liquid component on the substrate and heating the dispersion.
[0010]
Preferably, the metal hydroxide is magnesium hydroxide. It is preferable that the deodorizing material layer further includes an adsorbent that captures odorous substances. The photocatalyst is preferably titanium oxide. The substrate is preferably made of a porous ceramic, ceramic fiber or metal material. The dispersion preferably further includes colloidal particles of silica. The adsorbent is preferably at least one selected from the group consisting of activated carbon, zeolite and silica.
[0011]
Further, the present invention is provided with a main body having a ventilation path, a refrigerant for cooling the inside of the ventilation path, a pipe for circulating the refrigerant, a flow rate regulator for the refrigerant circulating in the pipe, and provided in the ventilation path. A refrigeration cycle device including a deodorizing element, wherein the deodorizing element includes a substrate having a honeycomb shape and a deodorizing material layer provided on the substrate, and the deodorizing material layer includes a metal oxide and a photocatalyst. And a refrigeration cycle apparatus wherein the metal oxide is formed by applying a dispersion liquid composed of a metal hydroxide and a liquid component on the substrate and heating the dispersion.
It is preferable that the refrigeration cycle apparatus further includes a light source for irradiating the deodorizing element with light. Further, it is preferable that a heating means for heating the deodorizing element is provided. The heating means preferably has a function of heating the deodorizing element at 150 ° C. or higher.
[0012]
Further, the present invention provides (a) a step of forming a carrier layer composed of a metal oxide by applying a dispersion liquid composed of a metal hydroxide and a liquid component on a substrate having a honeycomb shape and heating the dispersion. (B) supporting a photocatalyst on the carrier layer.
The step (a) is preferably a step of forming the carrier layer by heating a coating film of the dispersion applied on the base material at 500 ° C. or higher in air.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
Embodiment 1
FIG. 1 is a sectional view of an example of the deodorizing element according to the first embodiment of the present invention.
The first deodorizing element 5 includes a substrate 1 and a deodorizing material layer provided on the substrate 1, and the deodorizing material layer includes a binder 2, a metal oxide 3, and a photocatalyst 4. . The substrate 1 may be in the form of a fiber such as a nonwoven fabric or may be in the form of a plate. In particular, a honeycomb shape having a large surface area is preferable. The binder 2 is used to improve the adhesion between the metal oxide 3 or the photocatalyst 4 and the substrate 1.
[0014]
Next, a method for manufacturing the first deodorizing element 5 will be described.
First, a dispersion comprising a metal hydroxide and a liquid component is prepared. It is preferable to disperse or dissolve the binder 2 or its raw material in addition to the metal hydroxide in the liquid component. In this case, the binder 2 is heated under high-temperature conditions when forming the metal oxide 3 from the metal hydroxide, and thus is preferably an inorganic material.
[0015]
As the binder 2 made of an inorganic material, for example, it is preferable to use, for example, an alkali-silicate glass, silica, or alumina. Further, the alkali-silicate glass preferably forms water glass in the liquid component, and silica and alumina are preferably dispersed in the liquid component as colloid particles.
[0016]
As the liquid component, those capable of uniformly dispersing the metal hydroxide can be used without any particular limitation. However, it is preferable to use water because of easy handling.
[0017]
The amount of the binder 2 to be dispersed or dissolved in the liquid component is preferably 1 to 100 parts by weight per 100 parts by weight of the metal hydroxide. If the amount of the binder 2 is too large, the effect of adsorbing the metal oxide obtained from the metal hydroxide will not be sufficiently obtained, and if the amount is too small, the adhesion between the metal oxide 3 or the photocatalyst 4 and the substrate 1 will be insufficient. The effect of improving the performance cannot be obtained sufficiently.
[0018]
Next, a coating film of the dispersion is formed on the substrate 1 by immersing the substrate 1 in the above-described dispersion. Then, the carrier film composed of the metal oxide 3 is formed by heating the coating film of the dispersion together with the base material 1 at a predetermined temperature in a high-temperature heating furnace or the like to change the metal hydroxide into the metal oxide 3. I do.
[0019]
The binder 2 may be provided on the base material 1 by any method other than being contained in the above-mentioned dispersion liquid. For example, a binder may be added to a raw material solution or a dispersion used when applying the photocatalyst 4 on the substrate 1.
[0020]
The base material 1 having a honeycomb shape has a large area covered with the metal oxide 3 and the photocatalyst 4 and has excellent heat resistance. Therefore, the base material 1 is made of porous ceramics, ceramic fibers, metal, or a mixture thereof. Is preferred. The shape of the metal oxide 3 obtained from the metal hydroxide may be a thin film or a particle.
[0021]
Examples of metal hydroxides include magnesium hydroxide, copper hydroxide, nickel hydroxide, lead hydroxide, calcium hydroxide, aluminum hydroxide, zinc hydroxide, strontium hydroxide, and cobalt hydroxide. Is more preferred.
[0022]
The heating temperature for obtaining the metal oxide from the metal hydroxide varies depending on the type of the metal hydroxide, but is about 150 to 700 ° C, particularly preferably 500 ° C or more. The heating is preferably performed in air or oxygen.
[0023]
As the photocatalyst 4, titanium oxide, tungsten oxide, zirconium oxide, zinc oxide, strontium titanate and the like are preferable, and titanium oxide is particularly preferable. Further, in the configuration of the first deodorizing element 5 described above, the carrier layer composed of the binder 2 and the metal oxide 3 is formed on the base material 1 and the photocatalyst 4 is supported on the layer. May be in a state of having penetrated into the carrier layer formed on the base material 1 and composed of the binder 2 and the metal oxide 3.
[0024]
Next, details of a method of supporting the photocatalyst on the deodorizing element will be described below.
First, a method using a photocatalyst raw material solution will be described.
As a raw material of the photocatalyst, a metal alkoxide compound such as titanium tetraisopropoxide, a suspension in which fine particles of the photocatalyst are dispersed, or the like can be used. The raw material solution is prepared by dissolving the raw material of the photocatalyst in a solvent such as alcohol or water containing a basic substance such as diethanolamine or an acidic substance such as nitric acid.
[0025]
Next, the substrate having the carrier layer is immersed in the obtained raw material solution and heated at 400 to 600 ° C. By the heating, the hydrolysis reaction of the metal alkoxide proceeds, and an oxide thin film serving as a photocatalyst is formed on the carrier layer. A method utilizing a hydrolysis reaction of a metal alkoxide is called a sol-gel method. Note that a metal hydroxide may be dispersed in the raw material solution of the photocatalyst.
[0026]
Next, a method using a dispersion of photocatalyst fine particles will be described.
First, photocatalyst fine particles having a particle diameter of several μm to several nm are mixed with a dispersion medium to prepare a photocatalyst dispersion liquid. A substrate having a carrier layer is immersed in the dispersion and heated at 100 to 600 ° C. to support photocatalyst fine particles in the fine pores of the carrier layer. The metal hydroxide may be dispersed in the dispersion of the photocatalyst. Further, as the dispersion medium, one that completely volatilizes by a heating operation may be used, or a dispersion medium containing a binder may be used. For example, it is preferable to use a colloidal solution of silica or the like.
[0027]
In addition to the above, a vapor deposition method such as CVD, (NH ₄ ) ₂ TiF ₆ The photocatalyst can be supported on the carrier layer by employing a liquid phase deposition method (LPD; Liquid Phase Deposition) using (hexafluorofluorotitanate) or the like as a starting material.
[0028]
The amount of the photocatalyst to be supported on the carrier layer is not particularly limited as long as the photocatalyst is sufficiently fixed to the carrier and a photocatalytic effect developed with light irradiation is confirmed. Further, the thickness of the deodorizing material layer formed on the base material is preferably several tens to several hundreds μm. If the thickness of the deodorizing material layer is too thin, the deodorizing effect becomes insufficient. If it is too thick, only the surface layer exerts the deodorizing effect, and the material of the lower layer cannot be used effectively.
[0029]
FIG. 2 is a partial cross-sectional view showing an example of a configuration of a deodorizing device including the deodorizing element of FIG.
The first deodorizing device 9 includes a first deodorizing element 5 and a light source 6. The light source 6 irradiates light to a photocatalyst carried by the first deodorizing element 5. The photocatalyst is activated when irradiated with light, and oxidizes and decomposes the odorous substance in contact with the photocatalyst to remove the odorous substance. As the light source 6, an ultraviolet lamp having an output peak at 380 nm or less, which is a wavelength effective for activating a photocatalyst such as titanium oxide, is preferable, and a hot cathode tube system or a cold cathode tube system may be used. Arrows in the drawing indicate the flow of air. When the air 7 containing the odorous substance passes through the inside of the first deodorizing device 9, the odorous substance is removed, and the clean air 8 is removed by the first deodorizing apparatus. Released outside the device 9.
[0030]
In the deodorizing element according to the first embodiment as described above, when the odorant is decomposed by the photocatalyst, the metal oxide produced using the metal hydroxide as a raw material has a cocatalytic effect. It is considered that the decomposition efficiency of the odorous substance is improved as compared with the case where only the photocatalyst is used. That is, it is considered that the activation energy of the decomposition reaction of the odor substance is reduced by the adsorption of the metal oxide with the odor substance, and the efficiency of the oxidative decomposition reaction of the odor substance by the photocatalyst is improved.
[0031]
In the present invention, the properties of the substrate surface can be designed to be acidic or basic depending on the type of the metal hydroxide. Therefore, the adsorption performance of the deodorizing element can be adjusted according to the type of the odor substance to be deodorized. For example, by setting the metal element of the metal hydroxide to a metal element having a small electronegativity such as Mg, Ca, Zn, Al, and Ni, the surface of the deodorizing element formed with the metal oxide exhibits basicity. become. On the other hand, since titanium oxide as a photocatalyst has an acidic solid surface, it can impart both acidic and basic properties to the deodorizing element. According to the deodorizing element thus manufactured, both acidic odor gas such as hydrogen sulfide and methyl mercaptan and basic odor gas such as ammonia and trimethylamine can be adsorbed and removed with high efficiency.
[0032]
In addition, by supporting the metal oxide and the photocatalyst on the base material in separate steps, it is possible to suppress the growth of the particles of the photocatalyst and to support the photocatalyst under a temperature condition suitable for each material. Further, the photocatalyst can be supported on the outermost surface of the deodorizing element. Therefore, the photocatalyst is not buried in the metal oxide, and the effect of the photocatalyst can be effectively exhibited.
Furthermore, not only the effect of adsorbing odorous substances during light irradiation, but also the time of non-irradiation of light, the lighting time of the light source can be shortened because the metal oxide exhibits a high ability to adsorb odorous substances. Further, compared to the case where only the photocatalyst is used, the amount of power consumption is smaller, and the odorant can be efficiently removed.
[0033]
Embodiment 2
FIG. 3 is a sectional view of an example of the deodorizing element according to the second embodiment of the present invention.
As shown in FIG. 3, the second deodorizing element 11 includes a base material 1 and a deodorizing material layer provided on the base material 1, and the deodorizing material layer includes a binder 2, a metal oxide 3, and an adsorbent. 10 and a photocatalyst 4. The binder 2 is used for improving the adhesion between the metal oxide 3, the adsorbent 10 and the photocatalyst 4 and the substrate 1. The binder 2 is preferably added to, for example, a dispersion of a metal hydroxide or a raw material solution or a dispersion used when the photocatalyst 4 is applied onto the substrate 1.
The second deodorizing element 11 can be manufactured by the same method as the first deodorizing element 5 described above, except that the adsorbent 10 is used.
Further, the amount of the adsorbent 10 dispersed or dissolved in the liquid component is preferably 1 to 100 parts by weight per 100 parts by weight of the metal hydroxide. Since the adsorbent 10 is heated under high temperature conditions when forming a metal oxide from a metal hydroxide, the adsorbent 10 is preferably an inorganic material such as activated carbon, zeolite, silica, and alumina. Is more preferred.
[0034]
In the configuration of the second deodorizing element 11 described above, a carrier layer composed of a binder 2, an adsorbent 10, and a metal oxide 3 is formed on a substrate 1, and a photocatalyst 4 is supported on the carrier layer. However, the photocatalyst 4 may be in a state in which the photocatalyst 4 has entered the carrier layer formed on the base material 1 and formed of the binder 2, the adsorbent 10, and the metal oxide 3. Further, as shown in FIG. 2 described above, the second deodorizing element 11 of the present invention can further comprise a light source to constitute a deodorizing device.
[0035]
In the present invention, since the adsorbent is supported, the ability to adsorb odorous substances is increased, and the effect of removing odorous substances can be improved. Therefore, by reducing the concentration of the odorant, the burden of the photocatalyst decomposing and removing the odorant can be reduced, and the lighting time of the light source for irradiating the photocatalyst can be shortened.
Further, since the surface properties of the adsorbent and the metal oxide are different from each other, irregularities are formed on the surface of the carrier layer when the adsorbent and the metal oxide are carried on the base material. Therefore, when a photocatalyst is supported on such a carrier layer, the surface area of the deodorizing material layer further increases, and odorous substances having various surface properties can be captured. In addition, since the adsorbent is supported, a state in which the odorant is trapped near the photocatalyst is formed, so that the odorant can be efficiently decomposed.
[0036]
Here, the liquid component in which the metal hydroxide and the adsorbent are dispersed may or may not dissolve the metal hydroxide or the adsorbent, and may be a metal hydroxide or an adsorbent. There is no particular limitation as long as the chemical reaction does not occur. In addition, when a metal oxide is formed from a metal hydroxide, since a heating operation is performed, the liquid component is preferably water or a mixed solution with water. It is preferable to use an aqueous solution containing colloidal silica in order to increase the water content.
[0037]
Embodiment 3
FIG. 4 is a configuration diagram of an example of the deodorizing device according to the third embodiment of the present invention.
As shown in FIG. 4, the second deodorizing device 12 includes a heating means 13 provided on the suction port side of the air 7 containing the odor substance, a light source 6 provided on the air outlet side of the air 8 from which the odor substance has been removed, It includes a first deodorizing element 5 provided between the heating means 13 and the light source 6. The heating means 13 heats the surface of the first deodorizing element 5, and may be a direct heating method using a heater wire or the like, or may be an indirect heating method in which heat is transmitted from another heat source. It will not be done. Further, it is preferable that the heating temperature by the heating means 13 can be set to 150 ° C. or higher.
[0038]
In the present invention, since the heating device is further provided, it is possible to heat and remove water molecules and odorant molecules adsorbed on the surface of the deodorizing element. Therefore, by reducing the concentration of the odorant, the burden of the photocatalyst decomposing and removing the odorant can be reduced, and the lighting time of the light source for irradiating the photocatalyst can be shortened. Further, the heating means can eliminate the poisoning of the metal oxide and the photocatalyst surface, and the deodorizing element can be used for a long period of time.
Although the deodorizing apparatus of the present invention has been described taking the configuration including the first deodorizing element 5 as an example, the deodorizing apparatus may include a second deodorizing element 11 instead of the first deodorizing element 5. With this configuration, the ability to adsorb and remove odorous substances is improved, and it is possible to reduce the lighting time of the light source required for exhibiting the effect of the photocatalyst.
[0039]
Next, an example in which the deodorizing device of the present invention is provided in a refrigeration cycle device will be described below. Here, the refrigeration cycle device includes a refrigerant, a pipe through which the refrigerant circulates, and a flow controller that adjusts the flow rate of the circulating refrigerant. The flow controller includes a compressor, a condenser, an evaporator, an electromagnetic expansion valve, and a capillary tube.
[0040]
Embodiment 4
FIG. 5 is a principal part plan view of an example of a refrigeration cycle apparatus including a deodorizing element according to Embodiment 4 of the present invention.
As shown in FIG. 5, the refrigerator main body 14 includes a refrigerator compartment 15 for storing foods and the like, a refrigerator compartment door 28, and a ventilation path 16 provided in a gap between the refrigerator main body 14 and the rear surface of the refrigerator compartment 15. In the ventilation path 16, a cooling effect is achieved by vaporizing the cool air circulation fan 20, the second deodorizing element 11, the light source 6 for irradiating light to the surface of the second deodorizing element 11, and the refrigerant circulating in the piping. The evaporator 17 which expresses is installed. On the side wall separating the refrigerator compartment 15 and the ventilation passage 16, there are provided a cool air outlet 18 for sending cool air from the ventilation passage 16 to the refrigerator compartment 15 and a cool air inlet 19 for sending cool air from the refrigerator compartment 15 to the ventilation passage 16. Have been. The arrow 21 in the figure indicates the flow of air inside the refrigerator main body 14.
[0041]
Various odorous substances are released from the food stored inside the refrigerator compartment 15. The air inside the refrigerator main body 14 is guided from the refrigerating room 15 to the ventilation path 16 through the cool air suction port 19 together with the operation of the cool air circulation fan 20. Then, it moves into the refrigerator compartment 15 again through the cool air outlet 18. At this time, the odorous substances introduced into the ventilation passage 16 from the cool air suction port 19 are removed when passing through the second deodorizing element 11, and the clean air passes through the cool air outlet 18 and is refrigerated again. Released into chamber 15.
[0042]
In the present invention, since the deodorizing element and the light source are provided in the ventilation passage, various odorous substances having acidic or basic characteristics and generated from the refrigerator compartment can be removed. Furthermore, since the surface of the deodorizing element is cleaned with a photocatalyst using a light source, a refrigeration cycle apparatus having an excellent deodorizing function over a long period of time can be provided. Therefore, there is provided a refrigeration cycle apparatus in which the odor substance does not harm the food stored in the refrigerator compartment and the odor substance does not stay in the refrigerator compartment even when used for a long time. can do.
[0043]
Embodiment 5
FIG. 6 is a cross-sectional view of a main part of an example of a refrigeration cycle apparatus including a deodorizing element according to Embodiment 5 of the present invention.
As shown in FIG. 6, the air conditioner main body 22 has a front panel 23 forming an air inlet, a pre-filter 24 for capturing a solid substance having a large particle diameter, a second deodorizing element 11, and light on the surface of the second deodorizing element 11. A light source 6 for irradiation, a heating means 13 for heating the surface of the second deodorizing element 11, a heat exchanger 25, a blower fan 26, and a wind direction plate 27 are provided. Arrow 21 in the figure indicates the flow of air.
[0044]
Indoor air contains various odorous substances such as harmful organic solvents such as formaldehyde and toluene, odors from foods, and pet urine odor. As for the flow of the air inside the air conditioner main body 22, the room air is guided into the air conditioner main body 22 through the front panel 23 together with the operation of the blower fan 26. The indoor air guided into the air conditioner main body 22 passes through the pre-filter 24 to remove solid substances such as dust and dust having a large particle diameter. The room air that has passed through the pre-filter 24 passes through the second deodorizing element 11 to remove odorous substances. The clean air from which the odorous substances have been removed is discharged to the outside of the air conditioner main body 22 while the wind direction is controlled by the wind direction plate 27 via the heat exchanger 25 and the blower fan 26.
[0045]
In the present invention, since the deodorizing element, the light source, and the heating means are provided inside the air conditioner, the water molecules and the molecules of the odorous substance adsorbed by the deodorizing element can be heated and removed by the heating means. Therefore, by reducing the concentration of the odorant, the burden of the photocatalyst decomposing and removing the odorant can be reduced, and the lighting time of the light source for irradiating the photocatalyst can be shortened.
[0046]
【Example】
Hereinafter, examples of the present invention will be described.
<< Example 1 >>
2 g of magnesium hydroxide powder was added to 1 L of a colloidal silica aqueous solution (Snowtex 30 Ml; manufactured by Nissan Chemical Industries, Ltd.) with stirring with a stirrer, and stirring was continued until the dispersion was uniform, thereby preparing a dispersion. At this time, the amount of silica contained in the aqueous colloidal silica solution was about 30% by weight. Subsequently, after a lapse of a predetermined time, a base material made of ceramic fibers (Honeyicle; manufactured by Nichias Corporation) is immersed in the dispersion, pulled up, and heated at 550 ° C. for 30 minutes in a high-temperature heating furnace. A carrier layer was prepared. After heating, the carrier layer is immersed in an aqueous solution of titania sol (STS-01; manufactured by Ishihara Techno Co., Ltd.), and an excess solution dropped at the time of removal from the aqueous solution of titania sol is removed by nitrogen gas blow, and then the solution is heated in a constant temperature furnace. Heated at ℃ for 30 minutes. In the deodorizing element thus manufactured, 400 mg of the photocatalyst material was supported on the substrate on which the carrier layer was formed. Next, the ability to remove odorous substances was evaluated using this deodorizing element.
[0047]
Methyl mercaptan (CH ₃ SH) gas was selected. In a container having a capacity of 6.7 L, the deodorizing element and a black light lamp (PL-S9W / 08; manufactured by Philips) having an output of 9 W to be used as a light source for activating a photocatalyst were installed. Then, after evacuation of the inside of the container with a vacuum pump, methyl mercaptan gas adjusted to have a concentration of 10 ppm with respect to dry air was introduced into the container.
[0048]
First, the concentration of methyl mercaptan gas after lapse of 60 minutes was measured without irradiating the light source installed in the container, and it was 0.1 ppm. The methyl mercaptan gas did not show a saturation tendency and had decreased to the concentration at the detection limit. Next, when the light source was continuously irradiated after the introduction of the methyl mercaptan gas was started, it was confirmed that the methyl mercaptan gas was removed to a concentration below the detection limit within a few minutes after the introduction of the gas.
[0049]
<< Comparative Example 1 >>
The substrate made of the same ceramic fibers as in Example 1 was immersed in the aqueous colloidal silica solution containing no metal hydroxide, and heated at 550 ° C. for 30 minutes in a high-temperature heating furnace to form a carrier layer. After the heating, the carrier layer was immersed in the titania sol aqueous solution, and an excess solution that was dropped at the time of being taken out of the titania sol aqueous solution was removed by nitrogen gas blowing, followed by heating at 200 ° C. for 30 minutes in a constant temperature furnace.
Using the thus prepared deodorizing element, 10 ppm of methyl mercaptan gas was introduced as an odor substance in the same manner as in Example 1, and the ability to remove the odor substance was evaluated. First, the concentration of methyl mercaptan gas after 60 minutes was measured without irradiating the light source installed in the container, was 1 ppm. However, when the light source was subsequently irradiated, a rapid decrease in the concentration of methyl mercaptan gas was confirmed.
[0050]
<< Comparative Example 2 >>
A substrate made of the same ceramic fibers as in Example 1 was immersed in a dispersion liquid in which 2 g of magnesium hydroxide powder was dispersed in 1 L of the aqueous colloidal silica solution, and dried at 100 ° C. for 30 minutes in a constant temperature oven. Was supported as a metal hydroxide to prepare a carrier layer. After drying, the carrier layer was immersed in the titania sol aqueous solution, and an excess solution dropped when taken out of the titania sol aqueous solution was removed by nitrogen gas blowing, followed by heating at 200 ° C. for 30 minutes in a constant temperature furnace.
Using the thus prepared deodorizing element, 10 ppm of methyl mercaptan gas was introduced as an odor substance in the same manner as in Example 1, and the ability to remove the odor substance was evaluated. First, the concentration of methyl mercaptan gas after a lapse of 60 minutes was measured without irradiating the light source installed in the container, and it was 8 ppm. That is, it was confirmed that the methyl mercaptan gas remained without being substantially removed. However, when the light source was subsequently irradiated, a rapid decrease in the concentration of methyl mercaptan gas was confirmed.
[0051]
<< Example 2 >>
2 g of magnesium hydroxide powder and 2 g of hydrophobic zeolite (Absentz 2000; manufactured by Union Showa Co., Ltd.) 2 g of colloidal silica (Snowtex PS-M; manufactured by Nissan Chemical Industries, Ltd.) are added while stirring with a stirrer, and the mixture is added uniformly. The mixture was continuously stirred until dispersed to prepare a dispersion. Then, this dispersion was applied to a base material (Honeyicle; manufactured by Nichias Corporation). Here, the method of applying the dispersion to the substrate may be any method such as a dipping method, a dropping method, or a spray method. Subsequently, after the dispersion was applied onto the substrate, the dispersion was heated in a high-temperature heating furnace at 500 ° C. for 30 minutes to prepare a carrier layer in which a porous thin film of an adsorbent and a metal oxide was formed on the surface of the substrate. Then, the carrier layer is immersed in an aqueous solution of titania sol (STS-01; manufactured by Ishihara Techno Co., Ltd.), and an excess solution dropped at the time of being taken out of the aqueous solution of titania sol is removed by blowing nitrogen gas, and then the solution is heated in a constant temperature furnace for 200 hours. Heated at ℃ for 30 minutes. In the deodorizing element thus manufactured, 45 mg of the photocatalyst was carried on the substrate on which the carrier layer was formed. Next, the ability to remove odorous substances was evaluated using this deodorizing element.
[0052]
Acetaldehyde (CH ₃ CHO) gas was selected. A cold cathode tube type UV lamp (K-CE150-26-HBA; manufactured by West Denki Co., Ltd.) was installed in a container having a capacity of 10 L as a light source for activating the deodorizing element and the photocatalyst. . Then, after evacuation of the inside of the container with a vacuum pump, acetaldehyde gas adjusted to have a concentration of 100 ppm with respect to dry air was introduced into the container.
First, the concentration of acetaldehyde gas after 20 minutes was measured without irradiating the light source installed in the container, was 1 ppm. Subsequently, after the measurement of the concentration, it was confirmed that when the light source was irradiated, the acetaldehyde gas was more efficiently removed.
[0053]
Except for not containing the adsorbent, the deodorizing element made of the same material as in Example 2 was used to evaluate the odor substance removal ability in the same manner as in Example 2.
First, the concentration of acetaldehyde gas after 20 minutes was measured without irradiating the light source installed in the container, and was found to be 10 ppm. That is, it was confirmed that the acetaldehyde gas was not removed much but remained almost.
[0054]
<< Example 3 >>
In a container having a capacity of 10 L, a deodorizing element similar to that of Example 1, a heating means for heating the deodorizing element, and a light source (a 9 W output black light lamp (PL-S9W / 08; Philips))).
[0055]
First, methyl mercaptan gas was used as an odor substance to be removed, and the residual concentration of the odor substance when no light was irradiated was measured.
After exhausting the air in the container, methyl mercaptan gas adjusted to have a concentration of 10 ppm with respect to dry air was introduced into the container. When the methyl mercaptan gas is repeatedly introduced into the container, the decreasing behavior of the methyl mercaptan gas in the container slows down with the lapse of time, and one month after the start of introduction of the methyl mercaptan gas, 60 minutes from the gas introduction. After the lapse of time, the concentration of methyl mercaptan gas in the container had increased to 1 ppm (initial capacity value: 0.1 ppm). Next, this deodorizing element was heated at 150 ° C. for 30 minutes by a heating means. Then, after the heating, the methyl mercaptan gas was again introduced into the container so as to have a concentration of 10 ppm. As a result, the residual concentration after a lapse of 60 minutes had decreased to the initial capacity value (0.1 ppm).
[0056]
Next, acetaldehyde gas was used as the odor substance to be removed, and after irradiation with light, the residual concentration of the odor substance when the heating means was used was measured.
After exhausting the air in the container, acetaldehyde gas adjusted to have a concentration of 100 ppm with respect to dry air was introduced into the container. Then, when the acetaldehyde gas is repeatedly introduced into the container, the concentration of the acetaldehyde gas in the container after 60 minutes from the gas introduction is 3 ppm (initial capacity value 1 ppm) at one month after the start of the introduction of the acetaldehyde gas. Met. Next, when this deodorizing element was heated by the heating means, the concentration of the acetaldehyde gas was reduced to the initial capacity value (1 ppm) and recovered to the deodorizing and removing ability of the acetaldehyde gas when the deodorizing element was manufactured.
[0057]
<< Example 4 >>
In a container having a volume of 10 L, a deodorizing element similar to that in Example 2, a heating means for heating the deodorizing element, and a light source (a 9 W output black light lamp (PL-S9W / 08; Philips)).
[0058]
First, ethyl alcohol gas was used as the odor substance to be removed, and the residual concentration of the odor substance when no light was irradiated was measured.
After the air in the container was exhausted, ethyl alcohol gas adjusted to a concentration of 10 ppm with respect to dry air was introduced into the container. When the ethyl alcohol gas is repeatedly introduced into the container, the decreasing behavior of the ethyl alcohol gas in the container slows down with the lapse of time, and one month after the start of the introduction of the ethyl alcohol gas, 60 minutes from the gas introduction. After the passage, the concentration of the ethyl alcohol gas in the container had increased to 3 ppm (initial capacity value: 0.1 ppm). Next, this deodorizing element was heated at 150 ° C. for 30 minutes by a heating means. Then, after the heating was completed, the ethyl alcohol gas was again introduced into the container so as to have a concentration of 10 ppm. As a result, the residual concentration after 60 minutes had been reduced to the initial capacity value (0.1 ppm).
[0059]
Next, acetaldehyde gas was used as the odor substance to be removed, and after irradiation with light, the residual concentration of the odor substance when the heating means was used was measured.
After exhausting the air in the container, acetaldehyde gas adjusted to have a concentration of 100 ppm with respect to dry air was introduced into the container. When the acetaldehyde gas is repeatedly introduced into the container, the concentration of the acetaldehyde gas in the container after 1 month from the start of the introduction of the acetaldehyde gas is 1 ppm (the initial capacity value is 0.1 ppm) after 60 minutes from the gas introduction. )Met. Next, when this deodorizing element was heated at 200 ° C. for 30 minutes by a heating means, the concentration of acetaldehyde gas was reduced to 0.1 ppm. Therefore, it was confirmed that the function of the deodorizing element was regenerated by the heating means, and the acetaldehyde gas was removed again to the concentration of the initial capacity value.
[0060]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a deodorizing element exhibiting an excellent deodorizing effect for any odorous gas exhibiting acidic or basic characteristics. By providing the above, it is possible to have a good deodorizing effect over a long period of time.
[Brief description of the drawings]
FIG. 1 is a sectional view of an example of a deodorizing element according to a first embodiment of the present invention.
FIG. 2 is a partial cross-sectional view showing an example of a configuration of a deodorizing device including the deodorizing element.
FIG. 3 is a sectional view of an example of a deodorizing element according to a second embodiment of the present invention.
FIG. 4 is a partial cross-sectional view illustrating an example of a configuration of a deodorizing device according to a third embodiment of the present invention.
FIG. 5 is a cross-sectional view of a main part of an example of a refrigeration cycle apparatus including a deodorizing element according to a fourth embodiment of the present invention.
FIG. 6 is a cross-sectional view of an example of a refrigeration cycle apparatus including a deodorizing element according to a fifth embodiment of the present invention.
[Explanation of symbols]
1 Substrate
2 Binder
3 Metal oxide
4 Photocatalyst
5 First deodorizing element
6 light source
7 Air containing odorous substances
8 Air with odorous substances removed
9 First deodorizing device
10 Adsorbent
11 Second deodorizing element
12 Second deodorizing device
13 heating means
14 Refrigerator body
15 Cold room
16 Ventilation path
17 Evaporator
18 Cold air outlet
19 Cold air inlet
20 Cooling air circulation fan
21 Airflow
22 Air conditioning equipment
23 Front Panel
24 Pre-filter
25 heat exchanger
26 blower fan
27 Wind direction board
28 Refrigerator door

Claims (13)

Consisting of a substrate having a honeycomb shape and a deodorizing material layer provided on the substrate,
The deodorizing material layer comprises a metal oxide and a photocatalyst,
A deodorizing element, wherein the metal oxide is formed by applying a dispersion comprising a metal hydroxide and a liquid component on the substrate and heating the dispersion. The deodorizing element according to claim 1, wherein the metal hydroxide comprises magnesium hydroxide. The deodorizing element according to claim 1, wherein the deodorizing material layer further includes an adsorbent for capturing an odorous substance. The deodorizing element according to claim 1, wherein the photocatalyst is titanium oxide. The deodorizing element according to claim 1, wherein the substrate is made of a porous ceramic, a ceramic fiber, or a metal material. The deodorizing element according to claim 1, wherein the dispersion further contains colloidal particles of silica. The deodorizing element according to claim 3, wherein the adsorbent is at least one selected from the group consisting of activated carbon, zeolite and silica. Refrigeration comprising a main body having a ventilation path, a refrigerant for cooling the inside of the ventilation path, a pipe for circulating the refrigerant, a flow rate regulator for the refrigerant circulating in the pipe, and a deodorizing element provided in the ventilation path. A cycle device,
The deodorizing element comprises a substrate having a honeycomb shape and a deodorizing material layer provided on the substrate,
The deodorizing material layer comprises a metal oxide and a photocatalyst,
A refrigeration cycle apparatus, wherein the metal oxide is formed by applying a dispersion comprising a metal hydroxide and a liquid component on the substrate and heating the dispersion. The refrigeration cycle apparatus according to claim 8, further comprising a light source that irradiates the deodorizing element with light. The refrigeration cycle apparatus according to claim 8, further comprising heating means for heating the deodorizing element. The refrigeration cycle apparatus according to claim 10, wherein the heating means has a function of heating the deodorizing element at 150 ° C or higher. (A) a step of applying a dispersion comprising a metal hydroxide and a liquid component onto a substrate having a honeycomb shape and heating the dispersion to form a carrier layer comprising a metal oxide; and (b) the carrier Supporting a photocatalyst on the layer. 13. The method according to claim 12, wherein the step (a) is a step of forming the carrier layer by heating the coating film of the dispersion applied on the base material at 500 ° C. or higher in air. Manufacturing method of deodorizing element.

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