JP5851578B1 - Photocatalyst composition and method for producing the same - Google Patents

Abstract

Provided is a photocatalyst composition capable of sustaining adsorption performance and decomposition performance. SOLUTION: Adsorbent particles 2 composed of light-transmitting zeolite, sepiolite, mesoporous silica, activated clay, or a mixture of these, tungsten oxide, titanium dioxide acting in the visible light region, or these The photocatalyst composition 1 which contains the photocatalyst particle 3 comprised from the mixture, and the adsorbent particle 2 and the photocatalyst particle 3 exist in a dispersed state. The photocatalyst composition 1 is formed with voids, and the photocatalyst composition 1 has 30 to 50% by volume of voids with respect to 100% by volume of the photocatalyst composition 1. [Selection] Figure 1

Description

  The present invention relates to a photocatalyst composition and a method for producing the same, and more particularly to a solid photocatalyst composition in which adsorbent particles and photocatalyst particles are present in a dispersed state and a method for producing the same.

  A method for improving the performance of decomposing volatile organic compounds (VOCs) and odorous substances by combining an adsorbent and a photocatalyst has been conventionally known.

  For example, Patent Documents 1 and 2 disclose deodorizers or deodorizing filters in which zeolite and a photocatalyst are combined.

  Specifically, FIG. 15 is a cross-sectional view schematically showing a deodorant described in Patent Document 1. As shown in FIG. 15, the deodorant 101 described in Patent Document 1 has a configuration in which the surface of the zeolite particles 102 is covered with fine particles 103 of a visible light responsive photocatalyst. According to the deodorant 101, it is possible to have a sufficient gas removal speed and a stable gas removal ability even in a situation where there is very little ultraviolet light such as indoors or in an automobile.

  Moreover, the deodorizing filter described in Patent Document 2 has a configuration in which a photocatalyst is supported on the surface of a porous molded body containing hydrophobic zeolite. Hydrophobic zeolite adsorbs malodorous components, but hardly adsorbs moisture, so that malodorous components can be collected at a high concentration. In addition, the collected malodorous component is efficiently decomposed by the action of the photocatalyst supported on the hydrophobic zeolite surface. Thereby, since the adsorbent is regenerated and the adsorptive power can be continuously used, it is said that the deodorizing power is very excellent.

JP 2007-167699 A (published July 5, 2007) Japanese Patent Laid-Open No. 2002-136811 (released on May 14, 2002)

  However, in the configurations described in Patent Documents 1 and 2, there is a problem that the adsorption performance of the adsorbent is insufficient and the decomposition performance of the photocatalyst is not sustained.

  Specifically, in each of the configurations described in Patent Documents 1 and 2, a photocatalyst is supported on the surface of the adsorbent. For this reason, the supported amount of the photocatalyst with respect to the adsorbent is limited to an amount by which the entire surface of the adsorbent is covered with the photocatalyst layer. However, as the amount of the photocatalyst supported increases, the amount of exposure on the surface of the adsorbent decreases, so that the adsorbent is not exposed to the decomposition target. As a result, the adsorption performance by the adsorbent cannot be exhibited sufficiently.

  Further, when used for a long period of time, the photocatalyst carried on the surface of the adsorbent is peeled off, so that the amount of the photocatalyst is insufficient. As a result, the decomposition performance by the photocatalyst may decrease with time.

  This invention is made | formed in view of said subject, The objective is to provide the photocatalyst composition which can maintain adsorption | suction performance and decomposition | disassembly performance. Another object of the present invention is to provide a photocatalyst composition capable of achieving both adsorption performance and decomposition performance.

  In order to solve the above problems, a photocatalyst composition according to one embodiment of the present invention is a solid photocatalyst composition containing adsorbent particles having at least one of light transmittance and light reflectivity, and photocatalyst particles. The adsorbent particles and the photocatalyst particles are present in a dispersed state.

  According to one aspect of the present invention, there is an effect that it is possible to provide a photocatalyst composition capable of maintaining adsorbent adsorption performance and photocatalyst decomposition performance. Moreover, according to one aspect of the present invention, there is also an effect that it is possible to provide a photocatalyst composition that can achieve both adsorption performance of the adsorbent and decomposition performance of the photocatalyst.

It is a schematic diagram which shows roughly the external appearance of the photocatalyst composition concerning Embodiment 1 of this invention. It is the schematic which shows the evaluation apparatus used for the gas adsorption decomposition performance evaluation of the said photocatalyst composition. It is a graph which shows the evaluation result of the gas adsorption decomposition performance of the said photocatalyst composition. It is a figure which shows the SEM image which image | photographed the said photocatalyst composition. It is a figure which shows the SEM image which image | photographed the conventional photocatalyst composition used as a comparison object. It is the graph which compared the gas adsorption performance of the said photocatalyst composition and the conventional photocatalyst composition. It is the graph which compared the gas decomposition performance of the said photocatalyst composition and the conventional photocatalyst composition. It is sectional drawing which shows typically the photocatalyst composition which concerns on Embodiment 2 of this invention. It is sectional drawing which shows typically the photocatalyst composition which concerns on Embodiment 3 of this invention. It is sectional drawing which shows typically the photocatalyst composition which concerns on Embodiment 4 of this invention. It is a perspective view which shows typically the external appearance of the photocatalyst composition which concerns on Embodiment 5 of this invention. It is sectional drawing which shows typically the photocatalyst composition which concerns on Embodiment 5 of this invention. It is the graph which compared the gas adsorption | suction performance per adsorbent particle amount of the said photocatalyst composition and the conventional photocatalyst composition. It is the graph which compared the gas adsorption performance per photocatalyst particle amount of the said photocatalyst composition and the conventional photocatalyst composition. It is sectional drawing which shows typically the deodorizer of patent document 1. As shown in FIG.

Embodiment 1
Hereinafter, embodiments of the present invention will be described in detail. The embodiment described below is an example of the present invention and does not limit the content of the invention.

[Configuration of Photocatalyst Composition 1]
First, the structure of the photocatalyst composition according to the present embodiment will be described with reference to FIG. FIG. 1 is a schematic view schematically showing the appearance of a photocatalyst composition 1 according to Embodiment 1 of the present invention. As shown in FIG. 1, the photocatalyst composition 1 of this embodiment is solid (solid), and the adsorbent particles 2 and the photocatalyst particles 3 form an aggregate that exists in a dispersed state. Further, voids 6 are formed in the photocatalyst composition 1.

  The adsorbent particles 2 are capable of adsorbing and / or decomposing an object to be decomposed of the photocatalyst composition 1. The adsorbent particles 2 have at least one of light transmittance and light reflectivity. Specifically, the adsorbent particle 2 has a property of transmitting or reflecting at least a part of light having a wavelength absorbed by the photocatalyst particle 3, or transmitting at least a part of light having a wavelength absorbed by the photocatalyst particle 3. It has the property of reflecting the part. For example, the adsorbent particles 2 can be composed of zeolite, sepiolite, mesoporous silica, activated clay, or a mixture of these (at least two).

  Zeolite, sepiolite and other minerals, mesoporous silica, and activated clay have a property that the longer the wavelength in the visible to near-ultraviolet wavelength region, the lower the light absorptivity and the higher the sum of light transmittance and light reflectance. Have The structure type of the zeolite is not particularly limited, and BEA, CHA, EMT, ERI, FAU, FER, GIS, HEU, LTA, LTL, MAZ, MEI, MEL, MFI, MOR, MTW, OFF, or MCM41, MCM48 Various structural types such as can be used. Moreover, the zeolite can be either a natural type or a synthetic type.

  The size (average particle diameter) of the adsorbent particles 2 is not particularly limited. For example, the diameter (in the case of spherical particles) or the maximum length (in the case of non-spherical particles) is 0.1 μm or more and 1 μm or less. Generally, it is a degree. The reason why the adsorbent particles 2 have at least one of light transmission and light reflection will be described later. In addition, the size (average particle diameter) of the adsorbent particles 2 indicates a value measured by measurement with an optical particle size distribution meter and observation with SEM / TEM.

  The photocatalyst particles 3 can adsorb and / or decompose the decomposition target of the photocatalyst composition 1 by absorbing light. That is, the photocatalyst particles 3 exhibit photocatalytic activity when irradiated with light having a wavelength having energy equal to or greater than the band gap. The wavelength of light absorbed by the photocatalyst particles 3 is not particularly limited. For example, the photocatalyst particles 3 may be a visible light responsive photocatalyst that absorbs visible light and exhibits photocatalytic activity, or may be an ultraviolet responsive photocatalyst that absorbs ultraviolet light and exhibits photocatalytic activity. Further, it may be a mixture of a visible light responsive photocatalyst and an ultraviolet responsive photocatalyst. However, the photocatalyst particles 3 are preferably a visible light responsive photocatalyst.

As the visible light responsive photocatalyst, for example, tungsten oxide made of WO ₃ , W ₂₅ O ₇₃ , W ₂₀ O ₅₈ , W ₂₄ O ₆₈ , or a mixture thereof is suitable. Further, titanium dioxide (TiO ₂ ) modified so as to act in the visible light region by introducing a specific metal ion or introducing nitrogen into the oxygen site may be used as a visible light responsive photocatalyst. The visible light responsive photocatalyst may be a mixture of tungsten oxide and titanium dioxide so modified.

On the other hand, examples of the ultraviolet-responsive photocatalyst include titanium dioxide (TiO ₂ : simply referred to as titanium oxide).

  The size of the photocatalyst particles 3 is not particularly limited, but is preferably smaller than the adsorbent particles 2. Thereby, the photocatalyst particles 3 can be reliably dispersed to the inside of the photocatalyst composition 1. As for the size (average particle diameter) of the photocatalyst particles 3, for example, the diameter (in the case of spherical particles) or the maximum length (in the case of non-spherical particles) is preferably about 1 nm or more and 10 nm or less. In addition, the size (average particle diameter) of the photocatalyst particles 3 is a value measured by measurement with an optical particle size distribution meter and observation with SEM / TEM.

  In the photocatalyst composition 1, the content (weight ratio) of the adsorbent particles 2 and the photocatalyst particles 3 may be set according to the use of the photocatalyst composition 1, and is not particularly limited. When emphasizing the effect of the adsorbent particles 2, the photocatalyst composition 1 containing more adsorbent particles 2 than the photocatalyst particles 3 may be used. On the other hand, when emphasizing the effect of the photocatalyst particles 3, the photocatalyst composition 1 containing more photocatalyst particles 3 than the adsorbent particles 2 may be used. For example, the weight ratio of the adsorbent particle 2 / photocatalyst particle 3 is preferably 1 to 9, and more preferably 1.5 to 4. Thereby, it becomes the photocatalyst composition 1 in which the effect (adsorption performance) of the adsorbent particles 2 and the effect (decomposition performance) of the photocatalyst particles 3 are balanced.

  Although the ratio (void ratio) of the voids 6 in the photocatalyst composition 1 can be arbitrarily set, for example, the volume ratio of the photocatalyst composition 1 is preferably 30 to 50% by volume with respect to 100% by volume. Here, the porosity indicates the ratio of the voids 6 (spaces) to the apparent volume of the photocatalyst composition 1. Thereby, light can reach the inside of the photocatalyst composition 1 also in the wavelength region in which the adsorbent particles 2 have light reflectivity, in the same manner as the wavelength region in which the adsorbent particles 2 have light transmittance. Further, the decomposition target penetrates into the gap 6 and can be sufficiently adsorbed by the adsorbent particles 2 inside the photocatalyst composition 1.

  The form of the photocatalyst composition 1 is not particularly limited as long as it is solid. As shown in FIG. 1, in the present embodiment, the photocatalyst composition 1 is composed of aggregates of adsorbent particles 2 and photocatalyst particles 3. The photocatalyst composition 1 may be in the form of powder, particles, pellets, honeycomb, or film, but is preferably in the form of pellets.

  In addition, the photocatalyst composition 1 may consist of the adsorbent particles 2 and the photocatalyst particles 3, and may contain other components. For example, various binders may be included.

[Method for Producing Photocatalyst Composition 1]
Next, the manufacturing method of the photocatalyst composition 1 is demonstrated. Although the manufacturing method of the photocatalyst composition 1 is not specifically limited, For example, the dispersion process of disperse | distributing the adsorbent particle 2 and the photocatalyst particle 3 from the surface of the photocatalyst composition 1 to the inside as follows is included. A manufacturing method is conceivable.

  Specifically, in the dispersion step, the powdery adsorbent particles 2 and the powdery photocatalyst particles 3 are mixed and fixed as a mass of these particles in a lump shape. That is, the method for producing the photocatalyst composition 1 includes a mixing step of mixing the adsorbent particles 2 and the photocatalyst particles 3 and a forming step of forming the adsorbent particles 2 and the photocatalyst particles 3 mixed in the mixing step. It is out. Thereby, the photocatalyst composition 1 can be manufactured.

  Moreover, the space | gap 6 can be formed in the photocatalyst composition 1 with the conditions of this fixed shaping | molding. For example, powdery adsorbent particles 2 and powdery photocatalyst particles 3 are mixed at a certain ratio, and fixed as a mass of these particles having a void (fixed molding inside photocatalyst composition 1). ), Adsorbent particles 2 in the form of powder and photocatalyst particles 3 in the form of powder are mixed at different ratios, and fixed by molding with a similar or different molding method (photocatalyst composition 1). The photocatalyst composition 1 in which the voids 6 are formed can be manufactured. In this production method, if the ratio of the powdery adsorbent particles 2 and the powdered photocatalyst particles 3 at the time of each fixed molding is the same, the composition ratio of the adsorbent particles and the photocatalyst particles is uniform. A photocatalytic composition can be produced.

  There is no restriction | limiting in particular as a shaping | molding method of the photocatalyst composition 1, Granulation by a ring die system or a flat die system, or granulation by a briquetting machine may be sufficient. Examples of other granulation methods applicable to the production of the photocatalyst composition 1 include spray drying, extrusion granulation, rolling granulation, and thermoforming granulation.

  In addition, when the photocatalyst composition 1 is produced by granulation, other components may be mixed in addition to the adsorbent particles 2 and the photocatalyst particles 3. A typical example of another component is a binder. For example, the photocatalyst composition 1 may be produced by mixing and molding an organic or inorganic binder such as clay, CMC (carboxymethylcellulose), and resins as the binder together with the adsorbent particles 2 and the photocatalyst particles 3. Good.

  The photocatalyst composition 1 thus produced is preferably formed into a substantially spherical shape from the viewpoint of handling and permeability of the decomposition target. The particle diameter (diameter) when forming into a substantially spherical shape is not particularly limited, but is preferably about 0.5 mm or more and 5 mm or less, for example. In other words, it is preferable to form the photocatalyst composition 1 in the form of a pellet having a particle diameter (diameter) of about 0.5 mm or more and 5 mm or less. If the particle diameter is less than 0.5 mm, there may be difficulty in handling, and if it is more than 5 mm, there may be a problem in terms of permeability of the decomposition target.

[Operation of Photocatalyst Composition 1]
Then, the effect | action of the photocatalyst composition 1 is demonstrated. As described above, the photocatalyst composition 1 includes the adsorbent particles 2 and the photocatalyst particles 3. Both the adsorbent particles 2 and the photocatalyst particles 3 can adsorb and / or decompose the decomposition target of the photocatalyst composition 1. The decomposition target may be in a gas or liquid state. Examples of the decomposition target include volatile organic solvents (VOC) such as toluene, xylene, and acetaldehyde, and odorous substances such as acetic acid, hydrogen sulfide, and methyl mercaptan. Since the photocatalyst composition 1 has an effect of removing the decomposition target object by adsorption or decomposition, it is suitable for uses such as deodorization and deodorization.

  The adsorbent particles 2 generally have a feature that when the adsorption speed is high, the adsorption does not proceed any more when the adsorbent particles 2 are saturated. On the other hand, the photocatalyst particle 3 has a feature that it is generally decomposed without being saturated while it has a slow decomposition rate. Therefore, when the adsorbent particle 2 and the photocatalyst particle 3 are combined, the adsorbent particle 2 quickly adsorbs the decomposition target object, and the decomposition target object adsorbed by the adsorbent particle 2 is decomposed by the photocatalyst particle 3. For this reason, the adsorbent particles 2 are not saturated. On the other hand, the decomposition rate of the photocatalyst particles 3 depends on the concentration of the decomposition target. Since the photocatalyst particles 3 decompose the decomposition target object adsorbed on the adsorbent particles 2 at a high concentration, the decomposition speed is also increased. Therefore, the photocatalyst composition 1 has a synergistic effect that the adsorbent particles 2 are not saturated and the decomposition rate by the photocatalyst particles 3 is high.

  In the photocatalyst composition 1 of the present embodiment, the adsorbent particles 2 and the photocatalyst particles 3 are present in a dispersed state. For this reason, for example, by installing the photocatalyst composition 1 in the gas atmosphere to be removed, the gas to be removed can be adsorbed by the effect of the adsorbent particles 2, and the photocatalyst particles 3 absorb light. The removal target gas can be decomposed by the effect of the photocatalyst particles 3.

  Further, in the photocatalyst composition 1, the photocatalyst particles 3 are present not only in the outermost surface of the photocatalyst composition 1 but also dispersed inside. However, the adsorbent particles 2 have at least one of light transmission and light reflection. For this reason, when the adsorbent particle 2 has light transmittance, light reaches the internal photocatalyst particle 3 directly. In addition, since the void 6 is formed in the photocatalyst composition 1, the adsorbent particles 2 can reliably reach the internal photocatalyst particles 3 through the voids 6 regardless of whether the adsorbent particles 2 are light transmissive or light reflective. The light reaches. In particular, minerals such as zeolite and sepiolite have a lower light absorptance as the wavelength is longer in the wavelength region from visible light to near ultraviolet, and the sum of light transmittance and light reflectance is increased. For this reason, if the adsorbent particles 2 are composed of zeolite, sepiolite, or a mixture thereof having high light transmittance, sufficient light can reach the internal photocatalyst particles 3.

  Thus, in the photocatalyst composition 1 of the present embodiment, the adsorbent particles 2 having at least one of light transmittance and light reflectivity, and the photocatalyst particles 3 exist in a dispersed state. Thereby, it is easy to handle, and a sufficient amount of the photocatalyst particles 3 can be secured without impairing the adsorption ability of the adsorbent particles 2. Therefore, it is possible to provide the photocatalyst composition 1 that exhibits high gas adsorption decomposition performance and hardly deteriorates in gas decomposition performance even after long-term use. Therefore, it is possible to provide the photocatalyst composition 1 that can maintain the adsorption performance of the adsorbent particles 2 and the decomposition performance of the photocatalyst particles 3. Moreover, the photocatalyst composition 1 which can make the adsorption | suction performance of the adsorbent particle 2 and the decomposition performance of the photocatalyst particle 3 compatible can be provided.

  Moreover, the space | gap 6 is formed in the photocatalyst composition 1 of this embodiment. Thereby, light can reach the inside of the photocatalyst composition 1 through the gap 6 even in the wavelength region in which the adsorbent particles 2 have light reflectivity, as in the wavelength region in which light permeability is present. In addition, the decomposition target object penetrates into the gap 6 and can be adsorbed on the adsorbent particles 2 inside the photocatalyst composition 1. In addition, by forming the gap 6 at a ratio of 30% by volume or more and 50% by volume or less with respect to 100% by volume of the photocatalyst composition 1, light can reach the inside of the photocatalyst composition 1 more reliably. In addition, the decomposition target can be sufficiently adsorbed by the adsorbent particles 2 inside the photocatalyst composition 1.

[Evaluation of Photocatalyst Composition 1]
(Production of Photocatalyst Composition 1 to be evaluated)
Tungsten oxide was used as the photocatalyst, ZSM-5 type zeolite as the adsorbent, and CMC as the binder. The weight ratio of tungsten oxide: zeolite: binder was 1: 8.5: 0.5, and a combination of extrusion granulation and rolling granulation was combined to produce a photocatalyst composition 1 in the form of pellets.

(Production of Photocatalyst Composition of Comparative Object (Comparative Examples 1 and 2))
[Comparative Example 1] Photocatalyst composition carrying a photocatalyst on a ceramic surface Tungsten oxide was used as a photocatalyst, and a porous (sponge-like) ceramic filter was used as a ceramic. A weight ratio of tungsten oxide: ceramic filter was 1: 9, and a photocatalyst composition having a photocatalyst supported on the ceramic surface was produced by impregnation.

[Comparative Example 2] Photocatalyst composition having photocatalyst supported on zeolite surface Tungsten oxide was used as a photocatalyst, and β-type zeolite pellets were used as an adsorbent. A weight ratio of tungsten oxide: zeolite was 1.5: 8.5, and a photocatalyst composition having a photocatalyst supported on the zeolite surface was produced by impregnation. In addition, although the structural type of the zeolite used by the evaluation object and the comparative example 2 differs, when the powder of each zeolite is evaluated alone, the same capacity (gas adsorption rate = 1.6 [h-1]) It was confirmed separately.

(Evaluation method)
FIG. 2 is a schematic diagram showing a measurement system (evaluation apparatus 10) used for gas adsorption decomposition performance evaluation of the photocatalyst composition 1. As shown in FIG. 2, the evaluation device 10 includes a light shielding box 11, a light source 12, a gas bag 13, and a petri dish 14. The light source 12 is installed so as to illuminate the floor surface from the center of the inner ceiling of the light shielding box 11. The gas bag 13 is installed in the center of the floor surface of the light shielding box 11, and the petri dish 14 is accommodated in the gas bag 13. The light shielding box 11 has a structure that prevents light from being transmitted between the inside and the outside of the light shielding box 11, and the gas bag 13 is not irradiated with light other than the light emitted from the light source 12. A blue LED having a wavelength of 450 nm is used as the light source 12 and is irradiated with an irradiance of about 7 mW / cm ² . The gas bag 13 has a capacity of 5 L, is transparent in the vicinity of a wavelength of 450 nm, and has a structure that can be sealed so that gas cannot enter and exit. The petri dish 14 is made of quartz glass, and an object (photocatalyst composition 1) on which the gas adsorption decomposition rate is to be measured is placed.

  As the gas to be decomposed, acetaldehyde gas was used as a representative gas that causes VOC and various odors. The time dependence of the gas concentration change was measured, and the slope [h-1] when the logarithm of the gas concentration was plotted on the vertical axis and the time was plotted on the horizontal axis was defined as the gas adsorption decomposition rate. The time dependence of the concentration change due to gas adsorption and gas decomposition is such that the logarithm is on a straight line, so how much the initial concentration is does not affect the calculation of the slope, but here the initial concentration of gas is about 500 ppm. As measured. In other words, 500 ppm of acetaldehyde gas was enclosed in the gas bag 13 together with the petri dish 14 on which the measurement object (photocatalyst composition 1) was placed, irradiated with light from the light source 12, and the time dependence of the gas concentration change was measured. . Regarding the measurement of gas concentration, the detector tube No. 92 was used.

  At this time, only the gas adsorption rate due to the effect of the adsorbent particles 2 can be measured by not performing light irradiation from the light source 12.

(Evaluation results)
The gas adsorption decomposition rate of the photocatalyst composition 1 to be evaluated was measured by the evaluation method described above. FIG. 3 is a graph showing the evaluation results of the gas adsorption decomposition performance of the photocatalyst composition 1. In addition, the graph of FIG. 3 also shows the measurement result of a photocatalyst composition (Comparative Example 1) in which photocatalyst particles are supported on the surface of ceramics as a comparison object.

  As shown in FIG. 3, in the comparative example (ceramics + photocatalyst (surface supported)), since the adsorbent particles 2 do not exist, almost no gas adsorption decomposition is observed unless light is irradiated. However, the effect of the photocatalyst particles appeared by light irradiation, and the gas adsorption decomposition rate was measured to be 0.8 [h-1].

  On the other hand, in the photocatalyst composition 1 (zeolite + photocatalyst mixed pellet) to be evaluated, the gas adsorption rate when light is not irradiated is 1.5 [h-1], and the gas decomposition rate is obtained by light irradiation. It rose to 2.8 [h-1].

  From this, it can be seen that the photocatalyst composition 1 of the present embodiment not only simply added the effect of the photocatalyst particles 3 to the effect of the adsorbent particles 2, but also exhibited higher gas adsorption decomposition performance due to a synergistic effect. .

  Next, using FIG. 4 to FIG. 7, the photocatalyst composition 1 of the present embodiment and a conventional photocatalyst composition to be compared (photocatalyst composition in which photocatalyst particles are supported on the surface of adsorbent particles) are used. The comparison result will be described. FIG. 4 is a view showing an SEM image obtained by photographing the photocatalyst composition 1. FIG. 5 is a view showing an SEM image obtained by photographing a conventional photocatalyst composition to be compared (Comparative Example 2).

  Conventionally, as described in Patent Documents 1 and 2 described above, as a means for exerting the combined effect of adsorbent particles and photocatalyst particles, a method of supporting the photocatalyst particles on the surface of the adsorbent particles has been taken. It was. This is based on the idea that the photocatalyst particles must be irradiated with light in order to decompose the decomposition target such as gas, and the photocatalyst is arranged on the surface of the adsorbent particles that are easily irradiated with light.

  On the other hand, in the photocatalyst composition 1 of the present embodiment, the photocatalyst particles 3 are dispersed not only on the surface of the photocatalyst composition 1 but also inside.

  As described above, the photocatalyst composition 1 to be evaluated and the photocatalyst composition to be compared (Comparative Example 2) both use zeolite as the adsorbent particles, and the photocatalyst particles 3 have a weight ratio of about 10 to 20%. It is composed of.

  As shown in FIG. 4, many zeolite particles (adsorbent particles 2) having a particle size of about 0.5 μm are exposed on the surface of the photocatalyst composition 1 to be evaluated. The photocatalyst particle 3 is visible.

  On the other hand, as shown in FIG. 5, it can be seen that in the photocatalyst composition of Comparative Example 2, most of the surface of the zeolite (adsorbent particles) is covered with the photocatalyst particles. In such a configuration, photocatalyst particles are exposed on the surface, and zeolite is not exposed on the surface, so that the gas adsorption performance cannot be sufficiently exhibited.

  Next, measurement results of actual gas adsorption performance in the photocatalyst composition 1 and the conventional photocatalyst composition will be described with reference to FIG. FIG. 6 is a graph comparing the gas adsorption performance of the photocatalyst composition 1 and the conventional photocatalyst composition (Comparative Example 2). In addition, in FIG. 6, the measurement result of the gas adsorption rate of the pellet of the zeolite single which is not carrying the photocatalyst particle was also shown as a comparison.

  As shown in FIG. 6, the gas adsorption rate of the photocatalyst composition 1 to be evaluated (zeolite + photocatalyst mixed pellet) is 1.5 [h-1] which is almost the same as that of the zeolite pellet.

  On the other hand, the gas adsorption rate of the photocatalyst composition of Comparative Example 2 (zeolite pellet + photocatalyst (surface-supported)) is 1.2 [h−1], which is higher than that of the photocatalyst composition 1 to be evaluated and zeolite alone. It can be seen that the gas adsorption performance is low.

  When considering the result of the SEM image of FIG. 5 and the result of FIG. 6 together, the surface of the zeolite is covered with the photocatalyst particles, so that the photocatalyst particles 3 have an adverse effect on the gas adsorption performance of the adsorbent particles 2. Conceivable.

  Next, measurement results of actual gas adsorption performance in the photocatalyst composition 1 and the conventional photocatalyst composition will be described with reference to FIG. FIG. 7 is a graph comparing the gas decomposition performance of the photocatalyst composition 1 and the conventional photocatalyst composition (Comparative Example 2).

  As shown in FIG. 7, in all cases, the gas decomposition rate was 2.8 [h-1]. As a result, even when the photocatalyst particles 3 are present inside the pellet as in the photocatalyst composition 1, the light-transmitting adsorbent particles 2 and the visible light responsive photocatalyst particles 3 are used. This indicates that the light reaches the internal photocatalyst particles 3 sufficiently. For this reason, it is confirmed that the photocatalyst composition 1 has the same gas decomposition performance as the photocatalyst composition of Comparative Example 2 (zeolite pellet + photocatalyst (surface supported)) in which the photocatalyst particles are supported on the surface of the adsorbent particles. It was done.

  On the other hand, in the photocatalyst composition of Comparative Example 2, since the photocatalyst particles are supported on the surface of the zeolite pellets, in the unlikely event that powder falls from the pellets due to long-term use, the photocatalyst particles present on the surface preferentially. It will be peeled off. As a result, the gas decomposition performance decreases, and eventually the pellet becomes only the adsorbent particles.

  On the other hand, since the photocatalyst particle 3 exists in the photocatalyst composition 1, the gas decomposition performance can be maintained without losing completely even if it is used for a long time. Therefore, the photocatalyst composition 1 having a long lifetime can be realized.

  In the photocatalyst composition 1, the ratio (composition ratio) between the adsorbent particles 2 and the photocatalyst particles 3 is uniform at various locations inside the photocatalyst composition 1. Thereby, even if the powder falls off, the ratio between the adsorbent particles 2 and the photocatalyst particles 3 is always constant. For this reason, in the photocatalyst composition 1, the balance between adsorption and decomposition is always kept optimal. Further, when the adsorbent particles 2 and the photocatalyst particles 3 are extremely consumed, the same photocatalyst composition 1 is additionally replenished so that the gas adsorption and decomposition performance is maintained while maintaining the balance between adsorption and decomposition. Can be recovered.

  As described above, since the adsorbent particles 2 and the photocatalyst particles 3 exist in a dispersed state, the photocatalyst composition 1 can maintain the adsorption performance and the decomposition performance.

[Embodiment 2]
The following will describe another embodiment of the present invention with reference to FIG. For convenience of explanation, members having the same functions as those described in the embodiment are given the same reference numerals, and descriptions thereof are omitted.

  FIG. 8 is a cross-sectional view schematically showing a photocatalyst composition 1a according to Embodiment 2 of the present invention. As shown in FIG. 8, the photocatalyst composition 1a of the present embodiment is in the form of a substantially spherical pellet. Although not shown, in the photocatalyst composition 1a, the adsorbent particles 2 and the photocatalyst particles 3 are present in a dispersed state. The inside of the photocatalyst composition 1a has a two-layer structure of an outer layer (surface layer) 4a and an inner layer 5a. In the photocatalyst composition 1a, the ratio of the adsorbent particles 2 in the outer layer 4a is higher than the ratio of the photocatalyst particles 3, and the ratio of the photocatalyst particles 3 in the inner layer 5a is higher than the ratio of the adsorbent particles 2. That is, in the photocatalyst composition 1a, the abundance ratio of the adsorbent particles 2 and the photocatalyst particles 3 is non-uniform in the outer layer 4a and the inner layer 5a. The photocatalyst composition 1a has a two-layer structure, but may have a multilayer structure of three or more layers.

  According to the photocatalyst composition 1a, the content of the adsorbent particles 2 is higher in the outer layer 4a that is easier to touch the decomposition target. As a result, a function is realized in which the decomposition target is quickly adsorbed by the adsorbent particles 2 that are present more in the outer layer 4a, and the inner layer 5a having a high content of the photocatalyst particles 3 is decomposed slowly by more photocatalyst particles 3. be able to.

  Further, the photocatalyst composition 1a is consumed from the outside with a large proportion of the adsorbent particles 2 from a long-term viewpoint, so that the photocatalyst composition emphasizes adsorption in the short term and emphasizes decomposition in the long term. 1a pellets can be realized.

  As a method for producing the photocatalyst composition 1a having such a two-layer structure, for example, the inner layer 5a is once formed by molding using a die such as a briquette, a ring die, and a flat die, and then the outer layer 4a is changed by changing the material ratio. A method of molding again can be considered. The production method is not limited to these, and it is possible to produce a photocatalyst composition 1a having a multilayer structure of not only two layers but also three or more layers by molding in order from the inner layer 5a.

[Embodiment 3]
The following will describe another embodiment of the present invention with reference to FIG. For convenience of explanation, members having the same functions as those described in the embodiment are given the same reference numerals, and descriptions thereof are omitted.

  FIG. 9 is a cross-sectional view schematically showing a photocatalyst composition 1b according to Embodiment 3 of the present invention. The photocatalyst composition 1b in FIG. 9 is obtained by reversing the ratio of the adsorbent particles 2 and the photocatalyst particles 3 in the outer layer 4a and the inner layer 5a of the photocatalyst composition 1a in FIG. That is, the inside of the photocatalyst composition 1b also has a two-layer structure of the outer layer 4b and the inner layer 5b. In the photocatalyst composition 1b, the ratio of the photocatalyst particles 3 in the outer layer 4a is higher than the ratio of the adsorbent particles 2, and the ratio of the adsorbent particles 2 in the inner layer 5a is higher than the ratio of the photocatalyst particles 3. The photocatalyst composition 1b has a two-layer structure, but may have a multilayer structure of three or more layers.

  According to the photocatalyst composition 1b, the reverse function of the photocatalyst composition 1a can be realized. That is, according to the photocatalyst composition 1b, it is possible to realize a pellet of the photocatalyst composition 1b that emphasizes decomposition in the short term and emphasizes adsorption in the long term. Since the production method of the photocatalyst composition 1b is the same as that of the photocatalyst composition 1a, description thereof is omitted.

[Embodiment 4]
The following will describe another embodiment of the present invention with reference to FIG. For convenience of explanation, members having the same functions as those described in the embodiment are given the same reference numerals, and descriptions thereof are omitted.

  FIG. 10 is a cross-sectional view schematically showing a photocatalyst composition 1c according to Embodiment 4 of the present invention. The photocatalyst composition 1c in FIG. 10 is obtained by forming the inner layer 5a of the photocatalyst composition 1a in FIG. 8 into a multilayer structure. That is, the photocatalyst composition 1c includes an outer layer (surface layer) 4c and an inner layer 5c, and the inner layer 5c is composed of twelve layers 51 to 62.

  Further, in the photocatalyst composition 1c, the ratio (composition ratio) between the adsorbent particles 2 and the photocatalyst particles 3 is continuously changed from the outer layer 4c toward the inside. That is, in the outer layer 4c and the inner layer 5c (layers 51 to 62), the photocatalyst composition 1c has a non-uniform ratio of the adsorbent particles 2 and the photocatalyst particles 3. In the example of FIG. 10, the ratio of the adsorbent particles 2 is lower and the ratio of the photocatalyst particles 3 is higher toward the center of the photocatalyst composition 1c. However, conversely, the ratio of the adsorbent particles 2 may be higher and the ratio of the photocatalyst particles 3 may be lower toward the center of the photocatalyst composition 1c.

  Since the photocatalyst composition 1c has the same configuration as the photocatalyst composition 1a, the photocatalyst composition 1c has the same effects as the photocatalyst composition 1b.

  In the photocatalyst compositions 1a and 1b of the second and third embodiments, the composition ratio between the adsorbent particles 2 and the photocatalyst particles 3 changes rapidly between the outer layers 4a and 4b and the inner layers 5a and 5b. Cracking or peeling may occur during graining.

  On the other hand, in the photocatalyst composition 1c of the present embodiment, the composition ratio between the adsorbent particles 2 and the photocatalyst particles 3 continuously changes between the outer layer 4c and the inner layer 5c. It is possible to reduce the occurrence of cracks or peeling.

  As a production method of the photocatalyst composition 1c, for example, in a granulation method in which pellets are grown in order from the inner layer 5c (innermost layer 62) as in rolling granulation, a material to be added along with the growth is used. A granulation method in which the composition ratio is changed can be considered. The production method is not limited to this, and by using a granulation method for growing from the inner layer 5c (the innermost layer 62), the adsorbent particles 2 and the photocatalyst particles 3 can be formed according to the distance from the outer layer 4c (surface). The ratio can be controlled freely.

[Embodiment 5]
The following will describe another embodiment of the present invention with reference to FIGS. For convenience of explanation, members having the same functions as those described in the embodiment are given the same reference numerals, and descriptions thereof are omitted.

  FIG. 11 is a perspective view schematically showing the appearance of the photocatalyst composition 1d according to Embodiment 5 of the present invention. FIG. 12 is a cross-sectional view schematically showing a photocatalyst composition 1d according to Embodiment 5 of the present invention. As shown in FIG. 11 and FIG. 12, the photocatalyst composition 1d of the present embodiment is solid (solid) like the photocatalyst composition 1 of Embodiment 1, and the adsorbent particles 2 and the photocatalyst particles 3 are composed of Aggregates that existed in a distributed state are formed. Furthermore, as shown in FIG. 12, voids 6 are also formed in the photocatalytic composition 1d.

  The photocatalyst composition 1d is the most different from the photocatalyst composition 1 in that the distribution density of the photocatalyst particles 3 on the surface of the photocatalyst composition 1d is the highest. The distribution density of the photocatalyst particles 3 is not particularly limited. However, if the distribution density is high, the photocatalyst composition 1d emphasizes decomposition, and if the distribution density is low, the photocatalyst composition 1d is emphasized. That is, the higher the distribution density of the photocatalyst particles 3, the more the photocatalyst composition 1 d emphasizes the effect (decomposition performance) of the photocatalyst particles 3.

  Specifically, as shown in FIG. 12, in the photocatalyst composition 1d, the distribution density of the photocatalyst particles 3 is dense on the surface of the photocatalyst composition 1 and sparse inside. In other words, when the photocatalyst composition 1d is irradiated with parallel light from a certain direction, the areas of the photocatalyst particles 3 and the adsorbent particles 2 that are directly irradiated with the parallel light without considering the reflected light from the adsorbent particles 2. And the ratio of the volume of the photocatalyst particles 3 and the adsorbent particles 2 that are not directly irradiated with parallel light is “B”, the photocatalyst composition 1 has 1 / A ≠ 0, B ≠ 0, And A> B.

  The “A” can be expressed as the area occupied by the photocatalyst particles 3 on the apparent surface of the photocatalyst composition 1d / the area occupied by the adsorbent particles 2 on the apparent surface of the photocatalyst composition 1d. The “B” can be represented by the volume occupied by the photocatalyst particles 3 in the photocatalyst composition 1d / the volume occupied by the adsorbent particles 2 in the photocatalyst composition 1d. The apparent surface area of the photocatalyst composition 1d in “A” can be calculated from, for example, a photograph taken with an electron microscope or the like. Each volume in the “B” can be directly calculated by observation of a cross section or X-ray fluoroscopy, and the density and porosity of the photocatalyst composition 1d, the density of the photocatalyst particles 3 and the density of the adsorbent particles 2 By calculating the weight ratio from the above, the volume ratio can be calculated.

  In addition, the distribution density of the photocatalyst particles 3 may be a configuration in which the surface of the photocatalyst composition 1d is maximized and gradually decreases toward the inside.

  In the photocatalyst composition 1d, the photocatalyst particles 3 exhibit an effect by receiving light. Therefore, it is more efficient that the photocatalyst particles 3 are present on the surface of the photocatalyst composition 1d that receives light strongly. Therefore, it is preferable that the distribution density of the photocatalyst particles 3 on the surface of the photocatalyst composition 1d is the highest. That is, it is preferable that A> B. On the other hand, it is preferable that 1 / A ≠ 0 because the adsorbent particles 2 cannot exhibit the adsorption performance unless they contact the decomposition target. Even inside the photocatalyst composition 1 d, the reflected light and transmitted light of the adsorbent particles 2 reach and the light reaches the internal photocatalyst particles 3 directly through the gaps 6. Thereby, since the internal photocatalyst particles 3 also exert an effect, it is preferable that B ≠ 0.

[Method for Producing Photocatalyst Composition 1d]
Next, the manufacturing method of photocatalyst composition 1d is demonstrated. Although the manufacturing method of the photocatalyst composition 1d is not specifically limited, For example, the following manufacturing methods can be considered.

  For example, powdery adsorbent particles 2 and powdery photocatalyst particles 3 are mixed in a certain ratio (first mixing step) and fixed into a lump with a void as an aggregate of these particles (photocatalyst composition) 1d inside fixed molding) (first molding step), the powdery adsorbent particles 2 and the powdery photocatalyst particles 3 around the first photomolding particles 3 at a ratio higher than that in the first molding. Produced by mixing (second mixing step) and fixed molding (fixing molding of the surface of the photocatalyst composition 1d) with a void in the same or different molding method as in the first molding step (second molding step) can do. The molding method in the first molding step and the second molding step is the same as the molding method described in the first embodiment.

  The photocatalyst composition 1d can also be produced by performing a supporting step of further supporting the photocatalyst particles 3 on the surface of the molded product obtained by the molding step after the mixing step and the molding step in the first embodiment. Can do.

  By such a manufacturing method, the photocatalyst composition 1d can be easily manufactured.

  In addition, since the space | gap 6 is formed at the time of manufacture of the photocatalyst composition 1d of this embodiment, in the manufacturing method in [Evaluation of the photocatalyst composition 1d] described later, the photocatalyst particles 3 are formed on pellets composed of the adsorbent particles 2 and the binder. In the impregnation process, the photocatalyst particles 3 can be impregnated into the inside of the pellet.

[Action of Photocatalyst Composition 1d]
Thus, in the photocatalyst composition 1d of the present embodiment, the photocatalyst particles 3 are present not only in the outermost surface of the photocatalyst composition 1, but also dispersed inside. Moreover, the distribution density of the photocatalyst particles on the surface of the photocatalyst composition 1d is the highest. That is, the distribution density of the photocatalyst particles 3 is dense on the surface of the photocatalyst composition 1d and sparse inside. For this reason, in addition to the effect of the photocatalyst composition 1 of Embodiment 1, many of the photocatalyst particles 3 can receive light strongly, and the decomposition performance can be improved.

  Moreover, since the space | gap 6 is formed in the photocatalyst composition 1d, sufficient quantity of the photocatalyst particle 3 can be ensured, without inhibiting the adsorption | suction capability of the adsorbent particle 2. FIG.

[Evaluation of Photocatalyst Composition 1d]
(Production of Photocatalyst Composition 1d to be evaluated)
Tungsten oxide was used as the photocatalyst, ZSM-5 type zeolite as the adsorbent, and polyethylene as the binder. The weight ratio of tungsten oxide: zeolite: binder was 0.5: 4.5: 5 to form a pellet in which voids were formed by thermoforming, and then the photocatalyst was supported around the pellet by impregnation. The photocatalyst composition 1d in the form of pellets having a weight ratio of (surface) tungsten oxide: inner tungsten oxide: zeolite: binder of 1.7: 0.5: 4.5: 5 was produced.

  According to the optical surface observation, the “ratio of photocatalyst area / adsorbent area (A)” on the surface of the photocatalyst composition 1d was calculated to be about 100. Further, from the calculation of each density of the photocatalyst and the adsorbent, the ratio B of the photocatalyst volume / adsorbent volume within the photocatalyst composition 1d is calculated to be about 0.03, and the porosity of the photocatalyst composition 1d is about Calculated as 37%.

(Production of Photocatalyst Composition of Comparative Object (Comparative Example 3))
Tungsten oxide was used as the photocatalyst, ZSM-5 type zeolite as the adsorbent, and polyethylene as the binder. A photocatalytic composition in the form of pellets was produced by thermoforming at a weight ratio of tungsten oxide: zeolite: binder of 2.5: 2.5: 5.

  According to the optical surface observation, the photocatalyst area / adsorbent area ratio A is estimated to be about 0.005, and the photocatalyst volume / adsorbent volume ratio B is estimated to be about 0.03 from the density calculation. It was. The porosity of the photocatalyst composition of Comparative Example 3 was calculated to be about 37%.

(Evaluation method)
Similarly to the evaluation method of Embodiment 1, the photocatalyst composition 1d of the example and the photocatalyst composition of the comparative example were evaluated using the evaluation apparatus shown in FIG.

  As the gas to be decomposed, acetaldehyde gas was used as a representative gas that causes VOC and various odors. First, the change in gas concentration when acetaldehyde gas was adsorbed without irradiating light to the photocatalyst compositions of Example and Comparative Example 3 was measured, and the amount of gas decrease at the time when the change in gas concentration was not observed was determined as the adsorbent. The limit adsorption amount per unit amount of the adsorbent was determined. Next, the photocatalyst compositions of Examples and Comparative Examples were irradiated with light to decompose acetaldehyde gas. The average decomposition rate per unit amount of photocatalyst is calculated by calculating the amount of gas decomposition by measuring the change in carbon dioxide concentration caused by the decomposition of acetaldehyde gas, and dividing the slope of the change in the amount of decomposition by the amount of photocatalyst. It was. Regarding the measurement of the acetaldehyde gas concentration, the detector tube No. 92 and carbon dioxide detector tube No. 2LC was used.

(Evaluation results)
The limit adsorption amount and average decomposition rate of the photocatalyst composition 1d of the present embodiment were measured by the evaluation method described above. FIG. 13 is a graph showing the evaluation results of the limit adsorption amount of the photocatalyst composition 1d. In addition, the graph of FIG. 13 also shows the measurement result of the photocatalyst composition (Comparative Example 3) that does not carry photocatalyst particles on the surface as a comparison target.

  As shown in FIG. 13, in the photocatalyst composition 1d of this embodiment and the comparative example 3, the photocatalyst composition 1d of this embodiment has an advantage that the limit adsorption amount is equal. This is because the photocatalyst composition 1d of the present embodiment covers the entire surface of the photocatalyst composition 1 with photocatalyst particles 3, unlike the conventional examples described in Patent Documents 1 and 2 described above. It is considered that the adsorbent particles 2 are exposed on the surface, and there are voids throughout the interior, so that the gas permeates and is sufficiently adsorbed.

  Next, based on FIG. 14, the measurement result of the average decomposition rate in the photocatalyst composition 1d and Comparative Example 3 will be described. FIG. 14 is a graph comparing the gas decomposition performance of the photocatalyst composition 1d and Comparative Example 3.

  As shown in FIG. 14, the average decomposition rate was 26.3 [ppm @ 5 L / h] in the photocatalyst composition 1d with respect to 21.8 [ppm @ 5 L / h] in Comparative Example 3. As a result, even when the photocatalyst particles are present inside the pellet as in Comparative Example 3, the adsorbent particles 2 having light transmissivity and light reflectivity as in the photocatalyst composition 1d and the visible light response. It is shown that by using the photocatalyst particles 3 of the mold so as to have the voids 6, the light reaches the internal photocatalyst particles 3 sufficiently and the gas can be decomposed. Furthermore, the photocatalyst composition 1d has high decomposition efficiency because the photocatalyst particles 3 supported on the surface thereof directly receive light. For this reason, the photocatalyst composition 1d of this embodiment shows that the gas decomposition efficiency of the photocatalyst particles 3 is higher than that of Comparative Example 3 as a whole. Therefore, it was confirmed that the photocatalyst composition 1d has a higher average decomposition rate than Comparative Example 3 in which no additional photocatalyst particles are supported on the surface, and is superior in gas decomposition efficiency.

  As described above, in the photocatalyst composition 1d, the distribution of the photocatalyst particles 3 is dense on the surface and sparse inside. Thereby, the adsorption performance of the adsorbent and the decomposition performance of the photocatalyst can be sustained and compatible, and many of the photocatalyst particles 3 can receive light strongly, so that the decomposition performance can be improved.

[Embodiment 6]
The following will describe another embodiment of the present invention. In the present embodiment, a method for producing the photocatalyst composition 1d of Embodiment 5 will be described. For convenience of explanation, members having the same functions as those described in the embodiment are given the same reference numerals, and descriptions thereof are omitted.

  In the manufacturing method of the photocatalyst composition 1d in the present embodiment, the dispersing step of dispersing the adsorbent particles 2 and the photocatalyst particles 3 from the surface to the inside of the photocatalyst composition 1d uses the adsorbent particles 2 and the thermoplastic binder. A molding step for forming a molded product in which the voids 6 are formed, and a supporting step for supporting the photocatalyst particles 3 on the surface of the molded product in which the voids 6 are formed.

  For example, in the molding step, the powdery adsorbent particles 2 are fixed and molded into a lump with voids 6 using a thermoplastic resin (thermoplastic binder) as a binder. Furthermore, after the molding step, the supporting step is performed, whereby the photocatalyst particles 3 are supported on the surface of the molded product obtained in the molding step by an impregnation method. Thereby, photocatalyst composition 1d can be manufactured simply.

  The thermoplastic binder used in the molding process is, for example, a thermoplastic resin such as polypropylene or polyethylene. The molding method in the molding step is not particularly limited as long as it is a molding method in which heat is applied. For example, the molding method may be granulation by thermoforming, in which mixed particles of adsorbent particles 2 and thermoplastic binder are poured into a mold and heated to form.

  On the other hand, the impregnation method of the photocatalyst particles 3 in the supporting step is, for example, a method in which the photocatalyst particles 3 are dispersed in a solvent such as water or alcohol, and a molded product obtained by the molding step (a block-shaped fixed molded product having voids 6). ), And may be heated or dried at room temperature.

  According to such a method, in the supporting step, the dispersion liquid of the photocatalyst particles 3 penetrates not only to the surface of the fixed molded product obtained by the molding step but also to the gap 6 to some extent. For this reason, a certain amount of photocatalyst particles 3 can also be carried inside the fixed molded product. As a result, the photocatalyst particles 3 can be reliably dispersed even inside the photocatalyst composition 1d, and the photocatalyst particles 3 can be supported on the adsorbent particles 2 inside.

  Furthermore, in the manufacturing method of the present embodiment, after the supporting step, after the thermoplastic binder is softened by heating, the softened thermoplastic binder is cured, thereby fixing the photocatalyst particles 3 to the thermoplastic binder. It is preferable to further include a step.

  Thus, when the fixing step is performed after the supporting step of supporting the photocatalyst particles 3 by the impregnation method, the thermoplastic binder is softened and cooled to room temperature in the fixing step. Thereby, when a thermoplastic binder hardens | cures again, the photocatalyst particle 3 can be fixed to a thermoplastic binder. As a result, the photocatalyst particles 3 can be supported on the thermoplastic binder inside the photocatalyst composition 1d. Therefore, the photocatalyst particles 3 can be reliably supported inside the photocatalyst composition 1d.

[Embodiment 7]
The following will describe another embodiment of the present invention. In the present embodiment, another method for producing the photocatalyst composition 1d of Embodiment 5 will be described. For convenience of explanation, members having the same functions as those described in the embodiment are given the same reference numerals, and descriptions thereof are omitted.

  In the manufacturing method of the photocatalyst composition 1d in the present embodiment, the dispersing step of dispersing the adsorbent particles 2 and the photocatalyst particles 3 from the surface to the inside of the photocatalyst composition 1d includes the adsorbent particles 2 and the thermosetting binder. It includes a molding step for forming a molded product in which the voids 6 are formed, and a supporting step for supporting the photocatalyst particles 3 on the surface of the molded product in which the voids 6 are formed.

  For example, in the molding step, the powdery adsorbent particles 2 are thermoformed using a thermosetting binder that cures under a plurality of conditions as a binder. For example, a two-stage thermosetting binder that is thermally cured under two different conditions is used as the binder. Then, in the molding process, it is fixedly formed into a lump with gaps 6 by the first-stage curing. Furthermore, after the molding step, the supporting step is performed, whereby the photocatalyst particles 3 are supported on the surface of the molded product obtained in the molding step by an impregnation method. Thereby, photocatalyst composition 1d can be manufactured simply.

  The thermosetting binder used in the molding step is preferably a thermosetting binder that cures under a plurality of conditions. For example, as the thermosetting binder having such properties, a two-stage thermosetting resin that is thermoset under two different conditions, more specifically, a silicone resin or an epoxy resin can be given.

  The molding method in the molding step is not particularly limited as long as it is a molding method in which heat is applied. For example, the molding method may be granulation by thermoforming in which mixed particles of the adsorbent particles 2 and the thermosetting binder are poured into a mold and heated to form.

  On the other hand, the impregnation method of the photocatalyst particles 3 in the supporting step is, for example, a method in which the photocatalyst particles 3 are dispersed in a solvent such as water or alcohol, and a molded product obtained by the molding step (a block-shaped fixed molded product having voids 6). ), And may be heated or dried at room temperature.

  According to such a method, in the supporting step, the dispersion liquid of the photocatalyst particles 3 penetrates not only to the surface of the fixed molded product obtained by the molding step but also to the gap 6 to some extent. For this reason, a certain amount of photocatalyst particles 3 can also be carried inside the fixed molded product. As a result, the photocatalyst particles 3 can be reliably dispersed even inside the photocatalyst composition 1d, and the photocatalyst particles 3 can be supported on the adsorbent particles 2 inside.

  Furthermore, the manufacturing method of the present embodiment further includes a fixing step of fixing the photocatalyst particles 3 to the thermosetting binder by curing the thermosetting binder under the curing conditions different from the molding step after the supporting step. It is preferable.

  As described above, when the fixing step is performed after the supporting step of supporting the photocatalyst particles 3 by the impregnation method, second-stage curing occurs in the fixing step, and the photocatalyst particles 3 can be fixed to the thermosetting binder. As a result, the photocatalyst particles 3 can be supported on the thermoplastic binder inside the photocatalyst composition 1d. Therefore, the photocatalyst particles 3 can be reliably supported inside the photocatalyst composition 1d.

[Summary]
The photocatalyst compositions 1, 1a, 1b, 1c, and 1d according to the first aspect of the present invention are solid photocatalysts containing adsorbent particles 2 having at least one of light transmittance and light reflectivity, and photocatalyst particles 3. It is composition 1,1a, 1b, 1c, Comprising: It is the structure in which the said adsorbent particle 2 and the photocatalyst particle 3 exist in a dispersed state.

  According to the above configuration, the adsorbent particles and the photocatalyst particles exist in a dispersed state. That is, the photocatalyst particles do not exist only on the surface of the adsorbent particles as in the techniques described in Patent Documents 1 and 2, but exist in a dispersed state even inside the photocatalyst composition. Thereby, since adsorption | suction of the decomposition target object to adsorbent particle | grains is not inhibited by photocatalyst particle | grains, high adsorption | suction performance is exhibited.

  Furthermore, according to said structure, since it is not the structure which carries | supports a photocatalyst particle on the surface of adsorbent particle | grains (covering), more photocatalyst particles can be contained rather than the case. Further, the problem that the photocatalyst particles peel off from the surface of the adsorbent particles does not occur. In addition, since the adsorbent particles are light transmissive, sufficient light reaches the photocatalyst particles present inside. Thereby, the decomposition performance by a photocatalyst can be maintained.

  Therefore, it is possible to provide a photocatalyst composition that can maintain the adsorption performance and the decomposition performance. Moreover, the photocatalyst composition which can make adsorption performance and decomposition | disassembly performance compatible is provided.

  In the photocatalyst compositions 1, 1a, 1b, 1c, and 1d according to the second aspect of the present invention, in the first aspect, a void is preferably formed. In the photocatalyst compositions 1, 1a, 1b, 1c, and 1d according to the third aspect of the present invention, the proportion of the voids in the second aspect is 30 to 50% by volume with respect to 100% by volume of the photocatalyst composition. It is preferable.

  According to said structure, in the wavelength range in which the adsorbent particle | grains 2 have light reflectivity, it reaches | attains to the inside of a photocatalyst composition through a space | gap. That is, light can reach the inside of the photocatalyst composition even in a wavelength region where the adsorbent particles have light reflectivity, as in the wavelength region where light permeability is present. Further, the gas permeates into the voids, so that the adsorption can be sufficiently performed also in the adsorbent particles inside the photocatalyst composition.

  In the photocatalyst compositions 1, 1a, 1b, 1c, and 1d according to the embodiment 4 of the present invention, the photocatalyst particles 3 in the embodiments 1 to 3 are preferably made of a visible light responsive photocatalyst. The photocatalyst compositions 1, 1a, 1b, 1c, and 1d according to Aspect 5 of the present invention are the same as those in Aspect 4, wherein the photocatalyst particles 3 are composed of tungsten oxide, titanium dioxide that acts in the visible light region, or a mixture thereof. May be.

  According to the above configuration, the photocatalyst particles are composed of a visible light responsive photocatalyst such as tungsten dioxide or titanium dioxide that has been improved so that it also works in the visible light region, so by absorbing visible light, Shows photocatalytic activity. Thereby, it becomes possible to decompose | disassemble a decomposition | disassembly target object in a wavelength longer than an ultraviolet-responsive photocatalyst. Therefore, it is possible to provide a photocatalyst composition that stably exhibits adsorption performance and decomposition performance even in a situation where the amount of ultraviolet rays is extremely low, such as indoors and in automobiles.

  The photocatalyst compositions 1, 1a, 1b, 1c, and 1d according to Aspect 6 of the present invention are the Aspects 1 to 5, wherein the adsorbent particles 2 are made of zeolite, sepiolite, mesoporous silica, activated clay, or a mixture thereof. It is preferable to be configured.

  According to the above configuration, the adsorbent particles are composed of zeolite, sepiolite, mesoporous silica, activated clay, or a mixture of these, which has a high light transmittance particularly in the visible to near-ultraviolet wavelength region. Thereby, light can be reliably made to reach the photocatalyst particles existing inside the photocatalyst composition. Therefore, the adsorption performance and decomposition performance of the photocatalyst composition can be maintained for a long time.

  The photocatalyst compositions 1, 1a, 1b, 1c, and 1d according to the seventh aspect of the present invention are preferably in the form of pellets in the first to sixth aspects.

  According to said structure, since it is a pellet-form photocatalyst composition 1, 1a, 1b, 1c, 1d, compared with the case where it uses with powder, other support bodies etc. are not required, but gas adsorption It can be used as it is as a lump having a certain volume as long as the degradation performance is not lowered. Therefore, it can be used conveniently in terms of handling.

  The photocatalyst compositions 1, 1a, 1b, 1c, and 1d according to the eighth aspect of the present invention are in a substantially spherical pellet form in the seventh aspect, and may have a diameter of 0.5 mm or more and 5 mm or less. Thereby, the decomposition | disassembly target object to a photocatalyst composition can be osmose | permeated reliably, maintaining the simplicity of a handling surface.

  The photocatalyst composition 1d according to Aspect 9 of the present invention may have a configuration in which the distribution density of the photocatalyst particles on the surface of the photocatalyst composition 1d is the highest in Aspects 1 to 8.

  According to the above configuration, since the distribution of the photocatalyst particles 3 is dense on the surface of the photocatalyst composition 1d and is sparse inside, the photocatalyst particles 3 supported on the surface directly receive light. Decomposition efficiency increases.

  Further, if the gap 6 is formed in the photocatalyst composition 1d, the adsorbent particles 2 are exposed on the surface without covering the entire surface of the photocatalyst composition 1d with the photocatalyst particles 3. Thereby, the adsorption performance of the adsorbent and the decomposition performance of the photocatalyst are exhibited both on the surface and inside. Therefore, the adsorption performance of the adsorbent and the decomposition performance of the photocatalyst can be maintained more reliably and more reliably.

  In photocatalyst composition 1 according to aspect 10 of the present invention, in aspects 1 to 8, the composition ratio of adsorbent particles 2 and photocatalyst particles 3 may be uniform inside photocatalyst composition 1.

  According to said structure, adsorbent particle and photocatalyst particle exist uniformly in a photocatalyst composition. Therefore, it is possible to provide a photocatalyst composition in which the balance between adsorption and decomposition is always kept optimal.

  In the photocatalyst composition 1 according to the embodiment 11 of the present invention, the composition ratio between the adsorbent particles and the photocatalyst particles may be increased or decreased in accordance with the progress toward the inside of the photocatalyst composition in the embodiments 1 to 8. .

  According to the above configuration, the composition ratio between the adsorbent particles and the photocatalyst particles changes as it goes toward the inside of the photocatalyst composition, so that the adsorbent particles and the photocatalyst particles are unevenly present in the photocatalyst composition. To do. As a result, when the adsorbent particles decrease toward the inside, it is possible to realize a photocatalyst composition that emphasizes adsorption in the short term and emphasizes decomposition in the long term. On the other hand, when the adsorbent particles increase toward the inside, it is possible to realize a photocatalyst composition that emphasizes decomposition in the short term and emphasizes adsorption in the long term.

  The photocatalyst compositions 1, 1a, 1b, 1c, and 1d according to the twelfth aspect of the present invention may be configured to further include a binder in the first to eleventh aspects. Thereby, shaping | molding of a photocatalyst composition becomes easy and a photocatalyst composition can be manufactured simply.

  The production method of the photocatalyst composition 1, 1a, 1b, 1c, 1d according to the embodiment 13 of the present invention is a solid-state containing adsorbent particles having at least one of light transmittance and light reflectivity, and photocatalyst particles. It is a manufacturing method of a photocatalyst composition, Comprising: It is a method including the dispersion | distribution process of disperse | distributing the said adsorbent particle and photocatalyst particle from the surface to the inside of the said photocatalyst composition.

  According to said structure, the photocatalyst composition which can maintain adsorption | suction performance and decomposition | disassembly performance, and the photocatalyst composition which can make adsorption | suction performance and decomposition | disassembly performance compatible can be manufactured.

  The method for producing the photocatalyst compositions 1, 1a, 1b, 1c, and 1d according to the fourteenth aspect of the present invention is the method according to the thirteenth aspect, in which the dispersion step includes the mixing step of mixing the adsorbent particles and the photocatalyst particles, and the mixing A molding step of molding the adsorbent particles and the photocatalyst particles mixed in the step may be included. Thereby, a photocatalyst composition can be manufactured simply.

  The production method of the photocatalyst composition 1d according to the aspect 15 of the present invention may further include a supporting step of supporting the photocatalyst particles 3 on the surface of the molded product obtained by the molding step in the aspect 14.

  According to said structure, the photocatalyst composition 1d with the highest distribution density of the photocatalyst particle 3 in the surface of the photocatalyst composition 1d can be manufactured simply.

  In the production method of the photocatalyst compositions 1, 1a, 1b, 1c, and 1d according to Aspect 16 of the present invention, the dispersion step uses the adsorbent particles and the thermoplastic binder or the thermosetting binder in Aspect 13. A molding step for forming a molded product with voids formed thereon, and a supporting step for supporting the photocatalyst particles on the surface of the molded product with the voids formed therein.

  According to said structure, the photocatalyst composition which can maintain adsorption | suction performance and decomposition | disassembly performance, and the photocatalyst composition which can make adsorption | suction performance and decomposition | disassembly performance compatible can be manufactured simply.

  The production method of the photocatalyst composition 1d according to Aspect 17 of the present invention is the Aspect 16, wherein the molding step is performed by thermoforming using a thermoplastic binder, and in the supporting step, the void is formed by an impregnation method. The photocatalyst particles are supported on the surface of the product, and after the supporting step, the thermoplastic binder is softened by heating, and then the softened thermoplastic binder is cured to fix the photocatalyst particles to the thermoplastic binder. And a fixing step to be performed.

  According to the above configuration, in the supporting step, the dispersion step of the photocatalyst particles is infiltrated into the voids by impregnation so that the photocatalyst particles are supported in the molded product in which the voids are formed, and then the fixing step is performed. Thereby, the photocatalyst particles can be fixed to the thermoplastic binder by heating in the fixing step. Therefore, the photocatalyst composition 1d having the highest distribution density of the photocatalyst particles 3 on the surface of the photocatalyst composition 1d can be easily produced.

  In the production method of the photocatalyst composition 1d according to Aspect 18 of the present invention, in Aspect 16, the molding step is thermoformed using a thermosetting binder that is cured under a plurality of conditions. The photocatalyst particles are supported on the surface of the molded product in which voids are formed, and the photocatalyst particles are thermally cured by curing the thermosetting binder under the curing conditions different from the molding step after the supporting step. And a fixing step of fixing to the adhesive binder.

  According to said structure, the molded object in which the space | gap was formed is formed by hardening of the 1st step by a shaping | molding process. Further, in the supporting step, the dispersion of the photocatalyst particles is infiltrated into the voids by impregnation to support the photocatalyst particles in the molded product in which the voids are formed, and then the fixing step is performed. Thereby, the photocatalyst particle 3 can be fixed to the two-stage thermosetting binder by the second-stage curing by the fixing process. Therefore, the photocatalyst composition 1d having the highest distribution density of the photocatalyst particles 3 on the surface of the photocatalyst composition 1d can be easily produced.

  The gas adsorption decomposition pellet according to aspect 21 of the present invention is a pellet in which a powdery adsorbent and a powdery photocatalyst are mixed and fixed in a lump as an aggregate of powder, and the adsorbent has optical transparency. The photocatalyst is a visible light responsive type.

  According to said structure, since a sufficient quantity of photocatalyst can be ensured, it has a high gas adsorption decomposition performance, and can implement | achieve the gas adsorption decomposition pellet which a gas decomposition performance does not fall easily even if it uses it for a long time.

  In the gas adsorption decomposition pellet according to aspect 22 of the present invention, in aspect 21, the adsorbent may be composed of zeolite, sepiolite, or a mixture thereof.

  According to said structure, since it is an adsorbent which has a light transmittance especially, light can fully reach the inside of a pellet, and high gas decomposition performance can be implement | achieved.

The gas adsorption / decomposition pellet according to aspect 23 of the present invention is the gas adsorption decomposition pellet according to aspect 21 or 22, wherein the photocatalyst is introduced in the visible light region by introducing tungsten trioxide (WO ₃ ), a specific metal ion, or nitrogen at an oxygen site. It may be composed of titanium dioxide (TiO ₂ ) modified to work, or a mixture thereof.

  According to the above configuration, since it becomes possible to configure a photocatalyst having a characteristic that reacts particularly with visible light, it becomes possible to decompose gas even at a longer wavelength as compared with a photocatalyst that reacts with ultraviolet light, In general, since light having a longer wavelength can be used because the light permeability in the adsorbent is higher, high gas decomposition performance can be realized.

  The gas adsorption / decomposition pellet according to the embodiment 24 of the present invention is substantially spherical in the embodiments 21 to 23, and the diameter thereof may be about φ0.5 mm to φ5 mm.

  According to the above configuration, as compared with the case of using the powder as it is, it is used as it is as a lump having a certain volume as long as no other support is required and the gas adsorption decomposition performance is not deteriorated. Therefore, it can be used conveniently in terms of handling.

  In the gas adsorption / decomposition pellet according to the aspect 25 of the present invention, in the aspects 21 to 24, the abundance ratios of the adsorbent and the photocatalyst may be uniform at various locations inside the pellet.

  According to the above configuration, the ratio of the adsorbent and the photocatalyst can always be kept constant even when powder falling or the like occurs due to long-term use, and it becomes possible to continuously operate at an optimal ratio. In addition, it is possible to reduce a decrease in gas adsorption decomposition performance due to long-term use.

  In the gas adsorption / decomposition pellet according to the aspect 26 of the present invention, in the aspects 21 to 25, the existence ratio of the adsorbent and the photocatalyst may be expressed as a function of the distance from the pellet surface.

  According to said structure, although a density | concentration changes as gas and light osmose | permeate from the pellet surface, the ratio of an optimal adsorbent and a photocatalyst can be set freely according to it.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention. Furthermore, a new technical feature can be formed by combining the technical means disclosed in each embodiment.

  The photocatalyst composition of the present invention can be suitably used for air purifiers and deodorizers, and scenes of use include homes, conference rooms, stores, factories, medical institutions, automobiles, trains, ships, airplanes, etc. It can be suitably used.

1, 1a, 1b, 1c, 1d Photocatalyst composition 2 Adsorbent particle 3 Photocatalyst particle 6 Void

Claims (17)

A solid photocatalyst composition comprising adsorbent particles having at least one of light transmittance and light reflectivity, and photocatalyst particles,
The adsorbent particles and the photocatalyst particles are present in a dispersed state ,
A photocatalyst composition characterized in that the composition ratio of the adsorbent particles and the photocatalyst particles continuously increases or decreases in the direction toward the inside of the photocatalyst composition. The photocatalyst composition according to claim 1, wherein the photocatalyst composition has a multilayer structure of three or more layers. The photocatalyst composition according to claim 1 or 2 , wherein voids are formed. The photocatalyst composition according to claim 3 , wherein a ratio of the voids is 30 to 50% by volume with respect to 100% by volume of the photocatalyst composition. The photocatalyst composition according to any one of claims 1 to 4 , wherein the photocatalyst particles comprise a visible light responsive photocatalyst. The photocatalyst composition according to claim 5 , wherein the photocatalyst particles are composed of tungsten oxide, titanium dioxide acting in the visible light region, or a mixture thereof. The photocatalyst composition according to any one of claims 1 to 6 , wherein the adsorbent particles are composed of zeolite, sepiolite, mesoporous silica, activated clay, or a mixture thereof. Photocatalyst composition according to any one of claim 1 to 7, which is a form of pellets. The photocatalyst composition according to claim 8 , wherein the photocatalyst composition is in the form of a substantially spherical pellet and has a diameter of 0.5 mm or more and 5 mm or less. The composition ratio of the adsorbent particles and the photocatalyst particles continuously decreases as it goes toward the inside of the photocatalyst composition,
The photocatalyst composition according to any one of claims 1 to 9 , wherein the photocatalyst particles have the highest distribution density on the surface of the photocatalyst composition. The photocatalyst composition according to any one of claims 1 to 10 , further comprising a binder. A method for producing a solid photocatalyst composition comprising adsorbent particles having at least one of light transmittance and light reflectivity, and photocatalyst particles,
The adsorbent particles and the photocatalyst particles are separated from the surface of the photocatalyst composition so that the composition ratio of the adsorbent particles and the photocatalyst particles continuously increases or decreases as going to the inside of the photocatalyst composition. The manufacturing method of the photocatalyst composition characterized by including the dispersion | distribution process disperse | distributed inside. The dispersion step is
A mixing step of mixing the adsorbent particles and the photocatalyst particles;
The method for producing a photocatalyst composition according to claim 12 , further comprising a molding step of molding the adsorbent particles and the photocatalyst particles mixed in the mixing step. A method for producing a solid photocatalyst composition comprising adsorbent particles having at least one of light transmittance and light reflectivity, and photocatalyst particles,
A dispersion step of dispersing the adsorbent particles and the photocatalyst particles from the surface to the inside of the photocatalyst composition;
The dispersion step includes a mixing step of mixing the adsorbent particles and the photocatalyst particles, and a forming step of forming the adsorbent particles and the photocatalyst particles mixed in the mixing step,
Method of manufacturing the surface of the molded product obtained by the molding step, further photocatalyst composition you comprising a supporting step of supporting photocatalyst particles. A method for producing a solid photocatalyst composition comprising adsorbent particles having at least one of light transmittance and light reflectivity, and photocatalyst particles,
A dispersion step of dispersing the adsorbent particles and the photocatalyst particles from the surface to the inside of the photocatalyst composition;
The dispersion step is
A molding step for forming a molded article in which voids are formed using the adsorbent particles and a thermoplastic binder or a thermosetting binder,
The surface of the molded product the void is formed, the manufacturing method of the photocatalyst composition you; and a supporting step of supporting the photocatalyst particles. In the above molding process, thermoforming using a thermoplastic binder,
In the supporting step, the photocatalyst particles are supported on the surface of the molded product in which the voids are formed by an impregnation method,
A fixing step of fixing the photocatalyst particles to the thermoplastic binder by hardening the thermoplastic binder by heating after the supporting step and then softening the thermoplastic binder. Item 16. A method for producing a photocatalyst composition according to Item 15 . In the molding step, thermoforming using a thermosetting binder that cures under multiple conditions,
In the supporting step, the photocatalyst particles are supported on the surface of the molded product in which the voids are formed by an impregnation method,
After the loading step, by curing the heat-curable binder at different curing conditions and the molding process, according to claim 15, characterized in that it comprises a fixing step of fixing the photocatalyst particles in the thermosetting binder The manufacturing method of photocatalyst composition as described in any one of.