JP2005329360A - Cleaning material and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning material exerting a high photocatalytic activity, and its manufacturing method. <P>SOLUTION: The cleaning material contains ceramics as a base material, and has semiconductor particles and apatite particles having a photocatalytic activity on a base material surface. The apatite particles themselves have the photocatalytic activity. The apatite particles can be produced by generating precipitates from slurry containing raw materials comprising at least calcium and phosphorous acid, and heating the precipitates at 100-300°C under the presence of oxygen, and produce active oxygen species with the irradiation of ultraviolet rays including a wavelength of 254 nm or less. The base material is preferably a porous ceramic material having a three dimensional network structure. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a purification material comprising a photocatalyst exhibiting photocatalytic activity, a method for producing the same, and a purification module using the purification material.

As a means to eliminate bad odors in living spaces and work spaces, or a means to purify air polluted by harmful substances such as automobile exhaust gas, as a means to purify contaminated water such as domestic wastewater and industrial wastewater, A purification material (typically a fluid purification filter) provided with a photocatalyst such as titanium oxide is used. Conventionally, various studies have been made to further improve the photocatalytic activity of a purification material and efficiently purify air and water (see Patent Documents 1 to 5 and Non-Patent Document 1).
For example, Patent Documents 1, 2, 5 and Non-Patent Document 1 disclose a purification material for air or water in which a catalyst containing titanium oxide and calcium phosphate is supported on the surface of a porous substrate. Calcium phosphate has an action of adsorbing organic substances such as bacteria and viruses. For this reason, by adding calcium phosphate to titanium oxide having high photocatalytic activity, the organic substances as described above are adsorbed by calcium phosphate and decomposed by titanium oxide to effectively purify the germs and the like.

Japanese Patent Laid-Open No. 10-244166 JP 11-347407 A JP 2000-157867 A JP 2001-38218 A Japanese Patent Laid-Open No. 2001-232206 "Materials" (J. Soc. Mat. Sci., Japan), Vol. 51, No. 6, 599-603, June 2002

However, these conventional purification materials only use calcium phosphate as an adsorbent. Further, when the surface of a photocatalytic substance such as titanium oxide is partially coated with calcium phosphate, the specific surface area of the catalyst may be reduced, and the catalytic activity may be reduced.
Then, an object of this invention is to provide the purification | cleaning material which can exhibit a catalyst activity higher than before. Another object of the present invention is to provide a method for producing such a purifying material. Still another object of the present invention is to provide a photocatalyst processing apparatus (that is, a purification module) using such a purification material.

The purification material provided by the present invention is a purification material based on ceramic; semiconductor particles (typically titanium oxide particles) having photocatalytic activity and apatite particles are supported on the surface of the substrate. The apatite particles themselves have a photocatalytic activity.
In the purification material having such a configuration, the apatite particles themselves have photocatalytic activity. For this reason, even if a part of the surface of the semiconductor particles is covered with apatite particles and the catalyst surface is lowered, the photocatalytic activity of the apatite particles is not lowered. Therefore, extremely high photocatalytic activity can be exhibited with the excellent photocatalytic activity of the semiconductor particles. In addition, since the apatite particles have catalytic activity and have an organic substance adsorption action such as bacteria and viruses as in the past, they can adsorb and decompose organic substances and effectively purify germs and the like. .

In particular, the substrate is preferably a ceramic porous body having a three-dimensional network structure.
By using a ceramic porous body having a three-dimensional network structure, the specific surface area of the substrate can be significantly increased. For this reason, the quantity per unit volume of the photocatalyst (namely, semiconductor particle and apatite particle) which exists in this ceramic porous body surface part, ie, the specific surface area of a photocatalyst, can be increased. Therefore, the photocatalytic activity of these particles can be improved. Moreover, this ceramic porous body can permeate | transmit the to-be-processed fluid (gas and liquid) efficiently not only to the surface layer but to the inside. For this reason, the catalyst contact area of the fluid which passes per unit volume can be increased, and the outstanding photocatalytic activity can be expressed. Therefore, it is suitable as a fluid (gas, liquid) purification material (photocatalytic filter).

The apatite particles preferably generate active oxygen species by irradiation with ultraviolet rays having a wavelength of 254 nm or less.
By including such apatite particles, a high photocatalytic activity can be exhibited by effectively utilizing the wavelength of a predetermined region of ultraviolet rays.

Typically, the apatite particles are produced by generating a precipitate from a slurry containing a raw material containing at least calcium and phosphoric acid as constituents, and heat-treating the precipitate at 150 to 300 ° C. in the presence of oxygen. It has been done.
Since the apatite particles thus obtained have high photocatalytic activity, they are suitable as a photocatalyst in the present purification material. Further, since the firing temperature is relatively low, the specific surface area can be kept high, and particularly high photocatalytic activity can be realized.

As a preferable form of the present purification material, the particle size ratio between the semiconductor particles and the apatite particles held on the surface of the base material (average primary particle size of the semiconductor particles: average primary particle size of the apatite particles) is What is the range of 1: 2000-20: 1 is mentioned. Furthermore, it is particularly preferable that the weight composition ratio (weight of the semiconductor particles per unit volume of the purification material: weight of the apatite particles) is in the range of 20:80 to 95: 5.
A high specific surface area can be maintained by being constituted by this particle size ratio or further by this weight composition ratio. Furthermore, these particles are dispersed at an appropriate ratio and can have both high adsorbability such as bacteria and catalytic activity, and can exhibit particularly high adsorbability. Moreover, since the adhesiveness with respect to a base material is favorable, peeling of a photocatalyst is prevented.

Moreover, this invention provides the method which can manufacture suitably the purification | cleaning material taught in this specification. That is, the method for producing a purification material provided by the present invention is a method for producing a purification material having semiconductor particles having photocatalytic activity and apatite particles having photocatalytic activity on the surface of a substrate, the semiconductor having photocatalytic activity. A step of preparing a powder, an apatite powder having photocatalytic activity, and a base material; and a step of supporting a mixture of the semiconductor powder and the apatite powder on the surface of the base material.
Unlike such a method, that is, a conventional manufacturing method, a purification material capable of exhibiting high catalytic activity as described above can be easily obtained by using apatite powder having photocatalytic activity as a raw material for apatite particle components. Can be manufactured. The apatite powder also functions as a binder for the semiconductor powder, and can support the photocatalyst mixture on the surface of the substrate even at a relatively low temperature, for example, 200 ° C. or lower. For this reason, the purification material which has a high specific surface area, ie, photocatalytic activity, can be provided.

In this manufacturing method, in the step of preparing the apatite powder, a precipitate is generated from a slurry containing a raw material containing at least calcium and phosphoric acid as constituents, and the precipitate is 150 to in the presence of oxygen. It is preferable to include heat-treating at 300 ° C. to produce apatite powder having photocatalytic activity.
By this method, apatite particles having photocatalytic activity can be easily obtained from an inexpensive material. For this reason, the manufacturing cost is low, and therefore the excellent economic efficiency of the purification material can be realized.

In this production method, a preferred embodiment is a particle size ratio between the semiconductor powder and the hydroxide apatite powder (average primary particle size of the semiconductor powder: average primary particle size of the apatite powder) is 1: 2000 to 20: 1. These powders are supported on the surface of the substrate so as to be in the range. Furthermore, these powders are supported on the surface of the substrate so that the weight composition ratio (weight of the semiconductor powder per unit volume of the purification material: weight of the apatite powder) is in the range of 20:80 to 95: 5. Is particularly preferred.
By using a combination of the powders having this particle size ratio or even this weight composition ratio, a photocatalyst having a high specific surface area can be obtained, and appropriate organic substance adsorption ability and photocatalytic activity can be imparted. Moreover, since the adhesiveness with respect to a base material is favorable, it prevents that these photocatalysts peel from a base material.

  Another method for producing a purification material provided by the present invention is a method for producing a purification material having semiconductor particles having photocatalytic activity and apatite particles having photocatalytic activity on a substrate surface portion, wherein the photocatalytic activity is exhibited. A step of preparing a semiconductor powder and a base material, a step of preparing a slurry containing a raw material containing at least calcium and phosphoric acid as constituents, and mixing the semiconductor powder in the slurry in the presence of oxygen. It includes a step of heat-treating at 150 to 300 ° C. to obtain an apatite-carrying semiconductor powder, and a step of carrying the apatite-carrying semiconductor powder on the surface of the substrate.

  The purification material of the present invention can also be easily manufactured by the manufacturing method having such a configuration. In this method, a slurry containing a raw material containing at least calcium and phosphoric acid as constituents is used as a raw material for the apatite particle component. And apatite particle | grains can be formed on the semiconductor powder surface by heat-processing after mixing this slurry with semiconductor powder. By carrying this on the surface of the base material, it is possible to easily produce a purification material that can exhibit high catalytic activity as described above. The apatite particles formed on the surface of the semiconductor powder also function as a binder for the semiconductor powder, and can support the photocatalyst on the surface of the base material even at a relatively low temperature, for example, 200 ° C. or lower. For this reason, the specific surface area, ie, photocatalytic activity, can be maintained.

In this production method, the particle size ratio between the semiconductor particles and the apatite particles (the average primary particle size of the semiconductor particles: the average primary particle size of the apatite particles) is in the range of 1: 2000 to 20: 1. It is preferable to obtain an apatite-supporting semiconductor powder, and the weight composition ratio (weight of the semiconductor particles per purification material unit volume: weight of the apatite particles) is 99.9: 0.1 to 90.0: 10.0. It is particularly preferable to prepare the purification material so as to be in the range described above.
By setting such a particle size ratio, the apatite particles can be appropriately dispersed on the surface of the semiconductor particles. Further, the semiconductor particles can be strongly and uniformly bonded by the apatite particles having this particle size ratio, and a purification material having a photocatalyst having a stable structure on its surface can be obtained.

In the production method disclosed herein, it is preferable to use a ceramic porous body having a three-dimensional network structure as the substrate.
By using such a ceramic porous body, the amount of the photocatalyst supported per unit volume (or unit weight) of the purification material can be easily increased. In addition, since the fluid to be treated can permeate to the inside thereof, a fluid treatment purification material (for example, a gas purification filter or a water purification filter) having good treatment efficiency can be suitably manufactured.

Moreover, this invention provides the photocatalyst processing apparatus (purification module) provided with one of the purification | cleaning materials taught in this specification, and the light source which irradiates this purification | cleaning material with an ultraviolet-ray.
In the module having such a configuration, the fluid to be treated (gas or liquid) is circulated through the purification material while irradiating the purification material with ultraviolet light from the light source, thereby efficiently purifying the fluid (typically in the fluid). Can be decomposed by adsorption and photocatalysis.

  A preferable photocatalyst processing apparatus (purification module) includes a light source capable of generating ultraviolet rays having a wavelength of 254 nm or less. The photocatalytic activity of the apatite particles is particularly strong in the region near this wavelength. Therefore, the fluid to be processed can be purified efficiently.

  Hereinafter, preferred embodiments of the present invention will be described. It should be noted that the present invention is a matter other than matters particularly mentioned in the present specification (for example, the apatite used and its production method, the base material, and the particle size ratio and weight composition ratio of the semiconductor particles to the apatite particles). Matters necessary for the implementation of the above can be grasped as design matters of those skilled in the art based on the prior art in this field. The present invention can be carried out based on the contents disclosed in this specification and common technical knowledge in the field.

  The apatite particles featured in the present invention are required to have photocatalytic activity by themselves. The apatite particles may be obtained by any means as long as they exhibit photocatalytic activity, and are not particularly limited. The apatite includes one or a mixture of two or more of hydroxyapatite, carbonate apatite, fluoride apatite, and calcium phosphate. Of these, hydroxyapatite which is excellent in photocatalytic activity and organic substance adsorption action is particularly preferable.

In particular, it is preferable to produce a precipitate from a slurry containing a raw material containing at least calcium and phosphoric acid as constituents and heat-treat the precipitate at 150 to 300 ° C. in the presence of oxygen. That is, the present inventors were able to produce apatite having excellent photocatalytic activity by such a method. Therefore, the purification material of the present invention succeeded in improving the photocatalytic activity by using apatite having excellent photocatalytic activity.
Typically, apatite having excellent photocatalytic activity has any of the following properties.
(1) Containing structural water.
(2) The Ca / P molar ratio is 1.58 or more.
(3) The crystal structure is excellent in crystallinity in the a-axis direction.

  Here, as the calcium component used as a raw material of the apatite particles, a calcium-containing compound that inhibits the production of apatite or does not leave impurities in the apatite obtained is used without particular limitation. For example, calcium hydroxide, calcium carbonate, calcium nitrate, calcium chloride, calcium acetate, calcium fluoride and the like can be mentioned. Particularly preferred is calcium hydroxide.

The phosphoric acid component is not particularly limited as long as it is an acid component containing phosphorus that inhibits the production of apatite or does not cause impurities to remain in the obtained apatite. For example, phosphoric acid, calcium hydrogen phosphate, phosphorous acid, hypophosphorous acid and the like can be mentioned. Particularly preferred is phosphoric acid.
The apatite particles can be obtained by including the calcium component and the phosphoric acid component as described above in the slurry, and the slurry may further include other components suitable for obtaining apatite having a desired composition. it can. Examples thereof include, but are not limited to, a sodium component, a potassium component, a magnesium component, a chlorine component, a carbonic acid component, a sulfuric acid component, and a fluorine component.

  As a method for preparing the slurry, it is preferable to add a solution containing a phosphoric acid component to a solution containing a calcium component, for example, dropwise, but conversely, a solution containing a calcium component in a solution containing a phosphoric acid component May be added. Or you may mix in the same container simultaneously. These solvents are not particularly limited, and for example, water (preferably ion-exchanged water), organic solvents, dilute acids (such as nitric acid) and the like can be used.

As means for generating a precipitate from a slurry containing these calcium component and phosphoric acid component, a conventionally known uniform precipitation method can be appropriately selected and used. That is, apatite having a desired particle size and composition can be obtained by controlling the pH of the slurry solution, the concentration of each component, the reaction rate, and the like. By the precipitation method, fine particles having a uniform and uniform size can be obtained.
It is preferable to maintain the pH at, for example, 6 to 8, particularly 7.3 to 7.7. In this pH range, apatite particles are generated. The pH can be adjusted by adding any conventionally known pH adjusting agent. Examples thereof include, but are not limited to, sodium hydroxide, urea, thiourea, ammonium sulfate, acetic acid, carbonic acid, and hydrochloric acid.

  The composition ratio of the calcium component and the phosphoric acid component in the slurry is usually preferably a stoichiometric ratio. That is, the equivalent of 0.6 mol of phosphoric acid component is used for 1 mol of calcium component. However, it is not always necessary to use it in an accurate ratio. For example, a calcium component: phosphoric acid component can be appropriately used in a range of about 0.7: 0.6 to 1.5: 0.6. The total concentration of these components in the slurry is preferably adjusted to a range of 1 to 90% by weight, more preferably 3 to 30% by weight. If it is higher than this concentration, the slurry viscosity becomes high, and it is difficult to uniformly mix the slurry. On the other hand, if the concentration is lower than this concentration, the production amount is lowered, so that it is not efficient. In order to disperse them uniformly, a stirrer, ultrasonic vibration, or a dispersant that does not affect the product may be used. As the control of the reaction rate, heating, for example, heat treatment at room temperature to 80 ° C., addition of a catalyst, or reaction time can be controlled within a predetermined range, for example, 5 hours to 15 days. Usually, it is preferable to age at about room temperature to about 40 ° C. for about 10 to 80 hours, for example.

  The heat treatment temperature of the obtained precipitate is particularly important in that it exhibits photocatalytic activity, and is 150 to 500 ° C, preferably 150 to 300 ° C, more preferably 200 to 300 ° C. By a heat treatment at a temperature within this range, apatite particles capable of exhibiting photocatalytic activity can be obtained. The heat treatment atmosphere preferably contains oxygen and may be in an oxygen atmosphere, but is usually performed in the air.

  The method for producing such apatite particles is, for example, (Paper 1) Journal of Molecular Catalysis A: Chemical 206 (2003), pages 331 to 338 and (Paper 2) Journal of Molecular Catalysis A: Chemical 179 (200). Details are described on pages 193-200.

  The apatite particles obtained in this manner exhibit excellent photocatalytic activity. The wavelength of light exhibiting photocatalytic activity is not particularly limited in any wavelength range, and various wavelengths can be selected, but the apatite particles obtained as described above are particularly ultraviolet rays and more. Specifically, reactive oxygen species can be generated by ultraviolet light having a wavelength of approximately 254 nm or less, and can exhibit photocatalytic activity.

The average primary particle size of the apatite particles is not particularly limited, but is preferably about 5 nm to 10 μm, particularly about 5 to 100 nm. By having an average primary particle size in this range, a high specific surface area can be maintained, and semiconductor particles can be strongly bonded to the substrate surface portion, and thus a photocatalyst having a stable structure can be formed on the substrate surface portion. it can.
In the present specification, with respect to semiconductors such as titanium oxide and apatite, “particle” is a term indicating that these substances exist in a fine shape, and the form of individual particles is not limited. A semiconductor or apatite existing in a round and small shape on the surface of the substrate is a typical example of the particle referred to here, but is not limited to a round shape. It may be indefinite, and in the purification material of the present invention, these particles are usually bonded to each other to form a cluster or a layer.

  Next, semiconductor particles constituting the purification material of the present invention will be described. The semiconductor particles are not particularly limited as long as they are semiconductors that exhibit catalytic activity when irradiated with light, and can be appropriately selected from conventionally known ones. Examples include titanium oxide, tin oxide, zinc oxide, strontium titanate, tungsten oxide, zirconium oxide, niobium oxide, iron oxide, copper oxide, iron titanate, nickel oxide, bismuth oxide, and silicon oxide. Or a combination of two or more. Among these, titanium oxide and / or zinc oxide are preferable. In particular, titanium oxide is suitable because it exhibits excellent photocatalytic activity. Titanium oxide may be any of rutile type, anatase type, and brookite type, and particularly preferably an anatase type having high catalytic efficiency. These semiconductor particles may exhibit photocatalytic activity when irradiated with light of any wavelength. For example, what shows photocatalytic activity by the light of the wavelength of a ultraviolet-ray or visible region is mentioned. In particular, in order for apatite to exhibit photocatalytic activity in the ultraviolet region, those exhibiting photocatalytic activity by the same ultraviolet irradiation are suitable.

The average primary particle size of the semiconductor particles is not particularly limited, but is preferably about 5 to 100 nm, particularly about 5 to 50 nm. When the average primary particle size is in this range, an appropriate specific surface area can be maintained on the surface portion of the substrate, and thus high photocatalytic activity can be exhibited.
The particle size ratio between the semiconductor particles and the apatite particles (average primary particle size of the semiconductor particles: average primary particle size of the apatite particles) is not particularly limited, but is preferably 1: 2000 to 20: 1, particularly 1:20. -10: 1. The weight composition ratio of the semiconductor particles to the apatite particles (weight of the semiconductor particles per unit volume of the purification material: weight of the apatite particles) is preferably 20:80 to 95: 5, particularly 20:80 to The range is 60:40. By this particle size ratio and / or weight composition ratio, high adhesion to the substrate and specific surface area can be realized.

  In addition, in the purification material of the present invention, in addition to the semiconductor particles (metal oxide semiconductor) and apatite as photocatalysts as long as the photocatalytic activity and the binding property to the base material are not impaired, conventionally known photocatalysts such as various organics A polymer semiconductor, a metal complex, or the like can be used.

Moreover, as a base material used in the purification material of the present invention, a material having high mechanical strength and excellent durability is preferable. The shape is not particularly limited, and examples thereof include a plate shape, a cylindrical shape, a prismatic shape, a spherical shape, an elliptical spherical shape, and a granular shape. In particular, the substrate preferably has a large surface area (ie, specific surface area) per unit mass (volume). Therefore, a porous body is preferable. For example, a ceramic porous body, a honeycomb-shaped ceramic, etc. are mentioned. In particular, it has an uneven surface layer formed by adhering ceramic particles constituting an uneven surface layer (hereinafter referred to as “ceramic particles for the surface layer”) on the outer surface and pores of an inorganic porous body having a three-dimensional network structure. A porous body is preferred.
The material constituting the three-dimensional network structure (skeleton) of the porous body may be of any type as long as the desired mechanical strength can be maintained. Inorganic materials such as ceramics and metals are preferred, and ceramics are particularly preferred in terms of high strength and light weight. Oxide ceramics such as alumina and silica, or non-oxide ceramics such as silicon nitride and silicon carbide are preferable as the constituent material of the porous body as the base material.

  Moreover, it is preferable that the diameter of the skeletal muscle which comprises a three-dimensional network structure (skeleton) is about 100 micrometers-1000 micrometers. Thereby, it becomes easy to form pores (voids) through which the light irradiated to the purification material can be sufficiently transmitted to the inside. Therefore, the photocatalyst carried inside the porous body is sufficiently irradiated with light, and the catalytic activity can be sufficiently exhibited. When the diameter of the skeletal muscle is less than 100 μm, the strength of the purification material may be insufficient, which is not preferable. On the other hand, when the diameter exceeds 1000 μm, it is difficult to achieve both high specific surface area and porosity, which is not preferable.

The specific surface area of the porous body constituting the substrate is not particularly limited because it can be appropriately varied depending on the application. For purification material for gas treatment, 0.1m ² / cm ³ or more (e.g. 0.1~10m ² / cm ³⁾ is preferable, 1.0m ² / cm ³ or more (e.g. 1.0~10m ² / cm ³ ) is particularly preferred. In addition, the density of the porous body is not particularly limited because it can be appropriately varied depending on the material and application.

  Any kind of ceramics may be used as the surface layer ceramic particles. For example, an alumina particle etc. are mentioned. The average particle size is typically 1 μm to 100 μm. A porous body (preferably a ceramic porous body) having a concavo-convex surface layer formed by adhering ceramic particles having such a particle size has a large specific surface area and can carry a large amount of photocatalyst on the outer surface and pores. Since the surface area of a photocatalyst will become large if there is much loading, high photocatalytic activity can be provided to a purification material. When the average particle diameter of the ceramic particles for the surface layer is less than 1 μm, the uneven surface layer may not be sufficiently formed, which is not preferable. This is because the surface area cannot be improved. Further, when the average particle diameter exceeds 100 μm, it is not preferable because the ceramic particles for the surface layer are easily detached from the porous body.

In the purification material of the present invention, the weight of the photocatalyst (that is, the sum of the semiconductor particles and the apatite particles) with respect to the base material is not particularly limited, but is preferably about 0.01 to 0.1 g / cm ³ per base material volume, more preferably. Is 0.05 to 0.1 g / cm ³ . If the relative amount is less than 0.01 g / cm ³ , the photocatalytic activity tends to decrease, which is not preferable. On the other hand, when the relative amount is more than 0.1 g / cm ³ , the photocatalyst may be peeled off, which is not preferable.
In the purification material of the present invention, the base material is a porous body, and the light transmittance is changed by changing the density (porosity) of the porous body and the size of the photocatalyst (typically the particle size distribution) on the surface of the porous body. Can be significantly improved. For this reason, even if it is 3-20 mm in thickness, especially 5-15 mm (for example, 13.5 mm), it is excellent in the light transmittance of an ultraviolet-ray. Thereby, the thickness of the purification material can be increased practically and high photocatalytic activity (purification ability) can be exhibited.

Next, a suitable example of the method for producing the purification material described above will be described.
The substrate that can be used in the purification material is typically a ceramic body. A porous ceramic body is preferably prepared. A particularly suitable porous ceramic body can be produced, for example, as follows. First, ceramic fine powder (one kind or two or more kinds of fine powder composed of alumina, silica, mullite, etc. can be used) and a binder as binder (organic binders such as dextrin, methylcellulose, polyvinyl alcohol, clay) Any of the inorganic binders such as sodium silicate can be used) and water is added as appropriate and stirred to prepare a slurry for forming a ceramic porous body. Then, the slurry is impregnated into an organic porous body (such as polyurethane foam) having a predetermined shape (for example, plate shape) having a three-dimensional network structure. Next, before the porous body is dried, ceramic particles for the surface layer having an average particle diameter of 1 to 100 μm (one or more kinds of particles made of alumina, silica, mullite, etc. can be used) are made porous. Adhere to the body surface. After drying, the porous body is heated to burn off the organic matter and sinter the ceramic fine powder and the surface layer ceramic particles.

1 and 2, the ceramic in which the surface layer ceramic particles 5 are integrally held (sintered) on the surface of the skeletal muscle 3 constituting the porous body 1 having a three-dimensional network structure. A porous body 1 is obtained. As shown in FIG. 2, burnout marks 7 are formed in the portion where the organic porous body has been burned out. In FIG. 1, the skeletal muscle 3 is exposed by omitting the display of the ceramic particles 5 for the sake of explanation. Such a porous body having only skeletal muscle 3 can also be suitably used as a base material.
As the semiconductor particles, any semiconductor particles available as a photocatalyst, particularly titanium oxide can be used. Therefore, what is marketed may be obtained and what was manufactured by the conventionally well-known manufacturing method can be especially used without a restriction | limiting. Further, it is preferable to prepare the apatite particles manufactured as described above.

  Next, the process for supporting the photocatalyst on the substrate will be described. As a supporting method, a conventionally performed method can be employed without any particular limitation. For example, a slurry is prepared by dispersing a mixture of a powdered semiconductor and apatite in a solvent such as water (preferably ion-exchanged water), an organic solvent, a dilute acid (such as nitric acid), and the like. The concentration of the mixture in the slurry is preferably adjusted to 1 to 90% by weight, more preferably 3 to 30% by weight. If it is higher than this concentration, the viscosity of the slurry becomes high and it is difficult to mix the slurry uniformly. On the other hand, if it is lower than this concentration, the production amount is reduced, which is not efficient. The mixing ratio of the semiconductor powder and the apatite powder is preferably the weight composition ratio. In order to disperse them uniformly, a stirrer, ultrasonic vibration, or a non-influence dispersing agent may be used.

  Then, a base material, preferably a ceramic porous body is dipped (immersed) therein. The substrate is then dried. Although drying temperature is not specifically limited, It is room temperature to 300 degreeC, for example, 50-200 degreeC, Preferably it is 80-150 degreeC. Below this temperature, drying takes time. On the other hand, when the temperature is higher than this temperature, semiconductor particles and apatite particles grow, and the specific surface area, that is, the catalytic activity tends to decrease. The time is not particularly limited, but is usually 10 to 200 minutes, preferably 10 to 60 minutes. As a result, as shown in FIG. 3, the photocatalyst (typically the photocatalyst layer) 9 is supported (immobilized) on the surface portion of the ceramic porous body 1 (in the case of the ceramic porous body, the outer surface and inside the pores). be able to. In FIG. 3, the photocatalyst 9 has a uniform layer formed continuously, but is not limited thereto. For example, as shown in FIG. 4, a lump 9 a made of photocatalyst particles on the surface of the substrate 1. May be dispersed and supported. The film thickness, shape, composition, and the like of the resulting photocatalyst can be appropriately controlled by the concentration of each component of the slurry, the particle size of the raw material powder, the drying temperature, time, and the like.

As a photocatalyst carrying method, besides the dip method, a photocatalyst sol or slurry may be directly sprayed on a substrate (preferably a ceramic porous body).
Alternatively, the apatite particles can be formed in a state where they are supported on the surface of the semiconductor particles, in addition to being prepared and used in advance. That is, a semiconductor powder carrying apatite particles can be obtained by preparing a slurry containing a calcium component and a phosphoric acid component as used in the manufacture of apatite, and mixing this with a semiconductor powder followed by heat treatment. . As described above, the method of mixing and dispersing the slurry and the semiconductor powder can use a stirrer, ultrasonic vibration, or a dispersant that does not affect the slurry. Moreover, the same means as the precipitation method can be used for the production of apatite particles before the heat treatment. That is, the pH of the semiconductor powder mixed slurry solution, the concentration of each component, the reaction rate, and the like can be controlled. Since the preferred range is the same as the method for producing the apatite powder, the description thereof is omitted. Thereafter, the apatite particles having a desired particle size and composition can be formed on the surface of the semiconductor particles by heat treatment. The heat treatment is preferably performed in an oxygen atmosphere at a temperature range of about 150 to 300 ° C., particularly about 200 to 300 ° C. By being within this heat treatment temperature range, apatite particles having excellent photocatalytic activity can be formed.

And the obtained apatite carrying | support semiconductor particle is carry | supported by the base-material surface part. This supporting method can be carried out in the same manner as the supporting method of the photocatalyst mixture, that is, the dip or spraying method. Therefore, detailed description is omitted. According to this method, the particle diameter of the apatite particles can be reduced. That is, the particle size ratio between the semiconductor particles and the apatite particles in the apatite-carrying semiconductor powder (average primary particle size of the semiconductor particles: average primary particle size of the apatite particles) is preferably in the range of 1: 2000 to 20: 1. It can be in the range of 1:20 to 10: 1. For this reason, it can disperse | distribute uniformly on the surface of a semiconductor particle, and can show strong bond strength even if it is a small compounding ratio. The weight composition ratio (weight of the semiconductor particles per unit volume of the purification material: weight of the apatite particles) is preferably in the range of 99.9: 0.1 to 90.0: 10.0, particularly 99.7: It is the range of 0.3-90.0: 10.0. Thus, even if the quantity ratio of the semiconductor photocatalyst is increased, the photocatalyst can be prevented from peeling off from the substrate with a very high effect.

Moreover, according to this invention, the purification module (photocatalyst processing apparatus) comprised mainly by the purification | cleaning material mentioned above is provided. Specifically, the purification module of the present invention includes any of the purification materials taught herein and a light source capable of irradiating the purification material with ultraviolet rays.
The light source may be any light, but is preferably set so that ultraviolet light is emitted. For example, an ultraviolet light source may be used. Specifically, as a light source capable of mainly emitting ultraviolet light, a sterilizing lamp that emits ultraviolet light having a maximum wavelength near 254 nm, a black light, a UV light, a mercury lamp, deuterium that emits ultraviolet light having a maximum wavelength near 380 nm A lamp etc. are mentioned. Two or more of these light sources can be used in combination. In particular, those capable of irradiating ultraviolet rays having a wavelength of 254 nm or less (typically UV-C band enhancement type) are preferable. With this wavelength, the photocatalytic activity of the apatite particles can be sufficiently exhibited. For this reason, the photocatalytic activity of the apatite particles can be used effectively, and the light utilization efficiency is improved.

  The purification module of the present invention can be constructed as, for example, a gas processing module 10 as schematically shown in FIG. The module 10 is roughly composed of a gas introduction pipe 13, a gas discharge pipe 15, a casing 17 having an internal space through which gas can flow, and a light source 19. A gas introduction pipe 13 is communicated with the intake port 17 a of the casing 17. A gas discharge pipe 15 communicates with the exhaust port 17 b of the casing 17. A part of the gas discharge pipe 15 is equipped with a blower (not shown), and the gas to be treated can be introduced into the module 10 from the tip of the gas introduction pipe 13 by operating the blower. The introduced gas to be treated is discharged from the rear end of the gas discharge pipe 15 through the gas introduction pipe 13, the casing 17, and the gas discharge pipe 15 (see the arrow in the figure). The light source 19 is provided to face the lid portion 17c of the casing 17, and is configured to be able to irradiate light having a predetermined wavelength, preferably ultraviolet light with a predetermined intensity. For example, the light source 19 is a UV-C enhanced ultraviolet irradiation device (that is, a sterilization lamp) or a black light.

  A purification material 21 is built in the casing 17. The purification material 21 is disposed horizontally along the gas flow (progression) direction. Accordingly, the gas to be treated supplied from the gas introduction pipe 13 passes through the purification material 21 in the casing 17 and is discharged from the gas discharge pipe 15. The lid portion 17c of the casing 17 is made of a light transmissive material, for example, quartz glass, and transmits light emitted from the light source 19 to the inside thereof, that is, the purification material 21. Thereby, a photocatalytic reaction can be caused in the purification material 21, and the gas to be treated can be purified.

In the gas processing module 10 according to the present embodiment having the above-described configuration, the gas to be processed can be supplied into the casing 17 at a predetermined flow rate by operating the blower. Then, it is sequentially supplied to the purification material 21. At this time, the gas purification process based on the photocatalytic reaction is performed by irradiating the purification material 21 with light, particularly ultraviolet light, from the light source 19. The gas to be treated passes through the purification material 21 and can be effectively purified. The treated (purified) gas to be treated is discharged from the casing 17 and discharged to the outside through the gas discharge pipe 15 (see the arrow in the figure).
In addition, you may equip part of the gas introduction pipe | tube 13 with the adsorption | suction part 23 comprised from activated carbon etc. as needed. By removing the adsorbable substance in advance by the adsorbing unit 23, the purification efficiency of the purification material 21 can be further improved.

Alternatively, as shown in FIG. 6, the gas processing module 100 is separated from each other along the gas flow (progression) direction in the casing 117 so that the wide surface thereof is orthogonal to the gas flow direction. Individual purification materials (filters) 121a and 121b may be provided. A light source 119 (for example, a UV-C enhanced ultraviolet irradiation device, that is, a sterilization lamp) capable of irradiating both of the purification materials 21a and 121b with light, particularly ultraviolet light, is disposed between the purification materials 121a and 121b. Has been. Since the gas to be processed passes through the purification materials 121a and 121b twice (see the arrows in the figure), it can be effectively purified.
6 are the same as those of the module 10 shown in FIG. 5 described above. The other components in the module 100 shown in FIG. 6 (gas introduction pipe, gas discharge pipe, intake port and exhaust port of the casing 117, blower, adsorbent) are all the same. Yes, duplicate explanation is omitted.

Examples of the gas processed by the purification module of the present invention include smoke, malodorous components, atmospheric environmental pollutants such as NOx, SOx, and the like. Therefore, it can be preferably applied to deodorization and purification in automobiles, living rooms, kitchens, toilets, factories and the like.
Further, such a purification module can be used not only for purifying gas as described above, but also for purifying liquid, particularly contaminated water, for example, domestic wastewater and industrial wastewater. Specifically, it can be preferably applied to the purification of waste water, pools and stored water mixed with organic solvents and agricultural chemicals. Furthermore, by using the purification module of the present invention, it is possible to effectively prevent the growth of microorganisms such as fungi and fungi in the air or water.

Several examples relating to the present invention will be described below, but the present invention is not intended to be limited to those shown in the examples.
-Manufacture of photocatalytic filter having a mixture of titanium oxide powder and hydroxyapatite powder supported on the surface of the substrate-Manufacture of hydroxyapatite powder Hydroxyapatite was manufactured according to the method described in the papers 1 and 2. That is, calcium hydroxide and phosphoric acid were used as starting materials. 1 mol equivalent (74 g) of Ca (OH) ₂ slurry (solvent: ion-exchanged water, concentration: 37%) in 200 cm ³ and 0.6 mol equivalent (58.8 g) of H ₃ PO ₄ aqueous solution (concentration: 29.4%) 200 cm ³ was added dropwise at a rate of 10 cm ³ / min to produce a hydroxyapatite slurry. Next, an aqueous NaOH solution (concentration: 4%) was added to the obtained slurry to adjust the pH to 7.0, and then aging at room temperature for 48 hours to obtain a hydroxyapatite precipitate having a stoichiometric ratio. . The resulting precipitate was dried at 100 ° C. for 24 hours. Thereafter, a hydroxyapatite powder was obtained by heat treatment at 200 ° C. for 1 hour in an electric furnace. The Ca / P ratio in the obtained hydroxyapatite powder was 1.67 as measured by chemical analysis.

(2) Production of base material (porous body) 446.5 g of fine ceramic powder (alumina fine powder), 16.0 g of talc, 36.5 g of Kibushi clay, 155 g of water and dispersion in a 2 liter polyethylene pot mill 12.5 g of the agent was added. Further, alumina cobblestone having a diameter of 10 mm was added to about 1/3 of the pot mill and stirred and mixed for 5 hours. Next, 127.1 g of an organic binder (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., trade name “Ceramo TB-01”) was added to the pot mill, and the mixture was further stirred for 20 hours. Thus, the slurry for forming a ceramic porous body was prepared.
A plate-shaped organic porous body (here, urethane foam) having a three-dimensional network structure was immersed in this slurry, and the surface of the porous body was impregnated with the slurry. Next, the urethane foam was taken out of the slurry, and the excess slurry was removed by extruding with a roller. Next, the clogging was eliminated by blowing off the slurry clogged in the voids of the urethane foam using a spray.

Furthermore, the ceramic particles for the surface layer (alumina particles) having an average particle diameter of 8 μm were sprinkled on the slurry adhering to the urethane foam using a sieve to make it uniformly adhere. Then, excess alumina particles were removed, and the urethane foam to which the slurry adhered was dried in an oven at 70 ° C. for 24 hours, and then fired at 1600 ° C. for 1 hour. By this firing, the urethane foam was burned out and the alumina fine powder and alumina particles were sintered. In this way, a porous ceramic body was obtained in which the uneven surface layer made of the alumina particles was formed on the surface of the skeletal muscle constituting the three-dimensional network structure as shown in FIG.
When the bulk density of the obtained ceramic porous body was measured, it was 0.26 g / cm ³ . The surface area was about 0.5 m ² / g as measured by the BET method.

(3) Manufacture of photocatalytic filter TiO ₂ powder (manufactured by Nippon Aerosil Co., Ltd., trade name: P25) and the hydroxyapatite powder obtained by the above (1) in a ratio of 300 cm ³ in ion exchange water After stirring for 30 minutes with a stirrer and mixing, the resulting slurry was further uniformly dispersed by ultrasonic vibration for 15 minutes.
Next, the obtained slurry was dipped in the ceramic porous body obtained in (2) above and applied, and dried at 100 ° C. for 30 minutes. As a result, titanium oxide particles and hydroxyapatite particles were supported on the surface of the ceramic porous body. As schematically shown in FIG. 7, the titanium oxide particles and the hydroxyapatite particles are supported in a state where the titanium oxide particles 50 and the hydroxyapatite particles 51 are dispersed (typically in a cluster state). Yes.
The amount supported on the ceramic porous body was controlled to 10 g ± 1.0 g per volume of the ceramic porous body: 240 × 125 × 13 mm.

<2> Manufacture of a photocatalytic filter having a hydroxyapatite-supported titanium oxide powder supported on the substrate surface (1) Manufacture of a hydroxyapatite-supported titanium oxide powder Calcium hydroxide and phosphoric acid are used as starting materials for hydroxyapatite It was. 1 mol equivalent (74 g) of Ca (OH) ₂ slurry (solvent: ion-exchanged water, concentration: 37%) in 200 cm ³ and 0.6 mol equivalent (58.8 g) of H ₃ PO ₄ aqueous solution (concentration: 29.4%) 200 cm ³ was added dropwise at a rate of 10 cm ³ / min to produce a hydroxyapatite slurry. Next, TiO ₂ powder (manufactured by Nippon Aerosil Co., Ltd., trade name: P25) at a ratio shown in Table 2 below was added to the obtained slurry, and the mixture was stirred with a stirrer for 30 minutes.
And NaOH aqueous solution (concentration: 4%) was added to the obtained slurry, pH was adjusted to 7.0, and it dried at 100 degreeC for 24 hours. Then, the hydroxyapatite carrying | support titanium oxide powder was obtained by heat-processing in an electric furnace at 200 degreeC for 1 hour. As schematically shown in FIG. 8, the hydroxyapatite-supported titanium oxide powder has hydroxyapatite particles 56 having a smaller particle size dispersed and supported on the surface of the titanium oxide particles 54.

(2) Production of photocatalytic filter 100 g of the hydroxyapatite-supported titanium oxide powder obtained in (1) above was added to 300 cm ³⁻ of ion-exchanged water, and the mixture was stirred for 15 minutes with a stirrer and mixed.
Subsequently, the obtained slurry was dipped in the ceramic porous body obtained by the above <1> (2) and applied, and dried at 100 ° C. for 30 minutes.
The amount supported on the ceramic porous body was controlled to 10 g ± 1.0 g per volume of the ceramic porous body: 240 × 125 × 13 mm.

<3> Comparative Example (1) Comparative Example 1
As the photocatalytic filter of Comparative Example 1, the ceramic porous body obtained in the above (2) was used as it was. That is, no photocatalyst is supported.
(2) Comparative Example 2
A photocatalytic filter was produced in the same manner as in Preparation 4 except that the heat treatment temperature of the hydroxyapatite precipitate was 1150 ° C. instead of 200 ° C. That is, hydroxyapatite is inactive as a photocatalyst.
The hydroxyapatite powder used in Comparative Example 2 and the hydroxyapatite powder produced in <1> (1) as the above example were subjected to an X-ray diffraction (XRD) pattern using an X-ray diffractometer (Rigaku Multi (Flex diffractometer). The results are shown in FIG. As is clear from FIG. 10, the peak (002) in the c-axis direction shows the same sharp peak in any of the hydroxyapatite, that is, has the same crystallinity. However, the peak (300) in the a-axis direction shows a broad peak in the hydroxyapatite powder of this comparative example, while the example shows a sharp peak. Therefore, it can be seen that the hydroxyapatite powder of Comparative Example 2 has low crystallinity in the a-axis direction, while the hydroxyapatite powder of Example has high crystallinity in the a-axis direction. That is, these hydroxyapatite powders showed a difference in crystallinity in the a-axis direction, and it was confirmed that those having excellent crystallinity have high photocatalytic activity.
(3) Comparative Example 3
Ethyl silicate was added to a titanium oxide powder similar to that used in each of the above preparations with a weight ratio of SiO _{2 to} TiO ₂ of 3.0% (w / w). A total of 100 g was added to 300 cm ³⁻ of ion-exchanged water, mixed with stirring for 30 minutes with a stirrer, and the resulting slurry was further uniformly dispersed by ultrasonic vibration for 15 minutes.
Next, the obtained slurry was dipped in the ceramic porous body obtained by the above <1> (2) and applied, and baked at 600 ° C. for 30 minutes.
The amount supported on the ceramic porous body was 10.3 g per volume of the ceramic porous body: 240 × 125 × 13 mm.

<4> TiO ₂ Peeling Test The photocatalytic filter obtained by the above <1> and <2> was mounted on a vibration testing machine, a vibration test was performed, and a photocatalyst peeling amount due to vibration was obtained.
The conditions in the vibration tester were the Z direction in the thickness direction of the photocatalytic filter, acceleration: 0.8 G, vibration frequency: 5 to 50 Hz, vibration time: 10 minutes, and all vibrations in the Z direction. The results are shown in Table 3.

As is apparent from the results in Table 3, in the photocatalytic filter of <1>, in the preparation 11 in which the photocatalyst is composed only of titanium oxide, most of the titanium oxide particles were peeled off from the ceramic porous body. On the other hand, in the photocatalyst (formulation 2-7) in which the weight composition ratio of titanium oxide: hydroxide apatite is in the range of 20:80 to 95: 5, the peel amount of titanium oxide is less than 1 g, In particular, in the range of 20:80 to 60:40 (formulations 2 to 4), it was less than 0.01 g, indicating excellent binding properties of hydroxyapatite.
In the photocatalytic filter <2>, the titanium oxide is peeled off in a range where the weight composition ratio of titanium oxide: hydroxyapatite is 99.9: 0.1-90.0: 10.0 (formulation 12-19). The amount was less than 1 g, particularly less than 0.01 g in the range of 99.7: 0.3 to 90.0: 10.0 (formulations 13 to 19). For this reason, it was found that the filter using <2> titanium oxide-supported titanium oxide showed excellent binding properties even with a smaller amount.

<5> Measurement of specific surface area The same slurry as that immersed in the ceramic porous body in the above <1> and <2> (that is, slurry containing titanium oxide particles and hydroxyapatite particles in <1>, water in <2> The slurry containing acid apatite-carrying titanium oxide particles) was dried at 100 ° C. for 30 minutes, and the specific surface area was measured by the BET method. The results are shown in Table 4.

  As is clear from the results in Table 4, the specific surface area of all the photocatalysts was not significantly reduced even when compared with the titanium oxide alone of Formulation 11, except for Formulation 1, which was a photocatalyst of only hydroxyapatite. It was. In particular, the specific surface area of the photocatalyst (formulations 6 to 19) having a weight composition ratio of titanium oxide: hydroxide apatite in the range of 90:10 to 99.9: 0.1 was not substantially changed.

<6> Photocatalytic activity evaluation test (1) Dimethyl sulfide (DMS) decomposition and removal test In a gas treatment module 10a as shown in FIG. 9, DMS was treated by a photocatalytic reaction. That is, in the same gas processing module 10 as in FIG. 5, a DMS supply unit 25 and an air supply unit 27 that supply DMS and synthetic air (O ₂ + N ₂ ) are connected to the gas inflow side of the gas introduction pipe 13. These supply units 25 and 27 are provided with mass flow controllers 25a and 27a, respectively, capable of controlling the flow rates thereof. As the light source 19, a 20 W germicidal lamp (maximum wavelength 254 nm: UV-B, manufactured by Toshiba Lighting & Technology) was used. Further, in order to analyze the DMS concentration and the CO ₂ concentration of the discharged gas, a gas chromatograph (with a flame photometric detector, with FPD) 29 is disposed at the end of the gas discharge pipe 15 in the gas outflow direction.

Next, using this module 10a, a DMS odor decomposition and removal test was performed.
Gas was supplied from the DMS supply unit 25 and the air supply unit 27, respectively, and 50 ppm of DMS and synthetic air were mixed to adjust the DMS odor of a concentration of 1 ppm and an air volume of 1 L / min. Further, a photocatalytic filter (50 × 50 × 13 mm) produced in the same manner as in each of the preparation examples was disposed as the purification material 21 in the center of the casing 17. The lid 17a (quartz glass) was transmitted from the light source 19 and irradiated with ultraviolet rays at an intensity of 1 mW / cm ² for 60 minutes.
The photocatalytic activity was evaluated by the DMS concentration after passing through the purification material 21 and the CO ₂ production amount. The DMS concentration and CO ₂ production amount were measured by a gas chromatograph 29. The results are shown in Table 5.

As is apparent from Table 5, in the filter of Comparative Example 2, since hydroxyapatite does not have photocatalytic activity, it can be seen that the removal rate of DMS is significantly lower than the results of Formulations 2-19. Further, in the filter of Comparative Example 3, the photocatalytic activity is lowered due to the decrease in specific surface area due to grain growth by high-temperature treatment of titanium oxide and the influence of silica covering the surface of titanium oxide.
On the other hand, in the filters of Formulations 2 to 19, it was revealed that the DMS removal rate was extremely high of 99% or more. It was also found that most of DMS was converted to CO ₂ by oxidative decomposition. In Formulation 1, the DMS removal rate is slightly lower.
Further, in the filter of Comparative Example 1, the generation of CO ₂ is not recognized, it can be seen that the DMS decomposition removal is being performed by the photocatalyst.

(2) Acetaldehyde decomposition and removal test Instead of the DMS supply unit, an acetaldehyde supply unit was used, except that acetaldehyde (CH ₃ CHO) was introduced from the gas introduction pipe at a concentration of 1 ppm at an air flow rate of 1 L / min. The test was performed in the same manner as the DMS decomposition removal test. The results are shown in Table 6.

As is apparent from Table 6, in the filter of Comparative Example 2, since hydroxyapatite does not have photocatalytic activity, it can be seen that the removal rate of acetaldehyde is significantly lower than the results of Formulations 2-19. Further, in the filter of Comparative Example 3, the photocatalytic activity is lowered due to the decrease in specific surface area due to grain growth by high-temperature treatment of titanium oxide and the influence of silica covering the surface of titanium oxide.
On the other hand, in the filters of Formulations 2 to 19, it was revealed that the acetaldehyde removal rate was high and was 40% or more. In particular, the filter (formulations 6 to 19) in which the weight composition ratio of titanium oxide in the photocatalyst was 90% or more succeeded in removing 55% or more. In these filters, it was found that most (approximately 100%) of acetaldehyde was converted to CO ₂ by oxidative decomposition. In Formulation 1, the acetaldehyde removal rate is slightly low, which is about 30%.
Further, in the filter of Comparative Example 1, the generation of the removal of acetaldehyde and CO ₂ are not observed, it is seen that the decomposition and removal of acetaldehyde is being performed by the photocatalyst.

(3) Acetaldehyde adsorption test In the acetaldehyde decomposition and removal test, the acetaldehyde concentration and CO ₂ concentration after 10 minutes from the start of gas introduction were measured without irradiating ultraviolet rays. The results are shown in Table 7.

As is clear from Table 7, the filter of Comparative Example 3 does not have hydroxyapatite, the specific surface area has decreased due to grain growth by high-temperature treatment of titanium oxide, and silica covers the titanium oxide surface. As a result, the adsorption capacity is reduced.
On the other hand, in the filters of preparations 1 to 19, it was revealed that the acetaldehyde adsorption rate was high and was 55% or more. In particular, the filter obtained by the production method <1> succeeded in removing approximately 60% or more with a filter (formulations 1 to 7) having a weight composition ratio of hydroxyapatite in the photocatalyst of 5% or more. In addition, the filter obtained by the production method <2> succeeded in removing approximately 60% or more in all the preparations. Since the filter of Comparative Example 2 has hydroxyapatite, similar results are obtained. Moreover, in the filter of the comparative example 1, it is understood that acetaldehyde is hardly adsorbed and acetaldehyde is adsorbed by a photocatalyst.

  The preferred embodiments of the present invention have been described in detail above, but these are only examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the above-described embodiments. In addition, the technical elements described in the present specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology illustrated in the present specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

It is a schematic diagram which shows the structure of a ceramic porous body. It is the II-II sectional view taken on the line in FIG. It is a typical sectional view showing the state where the photocatalyst was carried on the surface of the ceramic porous body. It is typical sectional drawing which shows the state by which the photocatalyst was carry | supported on the surface of the ceramic porous body which concerns on other one Embodiment. It is explanatory drawing which shows typically the gas processing module which concerns on one Embodiment. It is explanatory drawing which shows typically the gas processing module which concerns on other one Embodiment. It is explanatory drawing which shows typically the form of the photocatalyst carry | supported by the photocatalyst filter of this invention which concerns on one Embodiment. It is explanatory drawing which shows typically the form of the photocatalyst carry | supported by the photocatalyst filter which concerns on other one Embodiment. It is explanatory drawing which shows typically the gas processing module used in order to test a gas processing capability in an Example. It is a graph which shows the XRD pattern of the apatite used in the Example and the apatite used in the comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Porous body 3 of three-dimensional network structure ... Skeletal muscle 5 of porous body ... Ceramic particle 7 for surface layer ... Burnt scar 9 ... Photocatalyst 9a ... Mass 10 and 100 consisting of photocatalyst particles ... Gas treatment module 13 ... Gas introduction pipe DESCRIPTION OF SYMBOLS 15 ... Gas exhaust pipe 17, 117 ... Casing 19, 119 ... Light source 21, 121a, 121b ... Purifier 23 ... Adsorption part 25 ... DMS supply part 27 ... Air supply part 29 ... Gas chromatograph

Claims (12)

A purification material based on ceramic;
Semiconductor particles having photocatalytic activity and apatite particles are supported on the surface of the base material,
A purification material, wherein the apatite particles themselves have photocatalytic activity.   The purification | cleaning material of Claim 1 whose said base material is a ceramic porous body which has a three-dimensional network structure.   The purification material according to claim 1 or 2, wherein the apatite particles generate active oxygen species by irradiation with ultraviolet rays having a wavelength of 254 nm or less.   The apatite particles are produced by generating a precipitate from a slurry containing a raw material containing at least calcium and phosphoric acid as constituents, and heat-treating the precipitate at 150 to 300 ° C. in the presence of oxygen. The purification material in any one of Claims 1-3.   The particle size ratio of the semiconductor particles and the apatite particles held on the surface of the substrate (average primary particle size of the semiconductor particles: average primary particle size of the apatite particles) is in the range of 1: 2000 to 20: 1. The weight composition ratio (weight of the semiconductor particles per unit volume of the purification material: weight of the apatite particles) is in the range of 20:80 to 95: 5. The purification material as described. A method for producing a purification material having semiconductor particles having photocatalytic activity and apatite particles having photocatalytic activity on a substrate surface portion,
A step of preparing a semiconductor powder having photocatalytic activity, an apatite powder having photocatalytic activity, and a substrate;
Carrying a mixture of the semiconductor powder and the apatite powder on the surface of the base material;
Manufacturing method. In the step of preparing the apatite powder,
Production of apatite powder having photocatalytic activity by generating a precipitate from a slurry containing a raw material containing at least calcium and phosphoric acid as constituents and heat-treating the precipitate at 150 to 300 ° C. in the presence of oxygen To do,
The manufacturing method of Claim 6 containing this.   The particle size ratio between the semiconductor powder and the hydroxide apatite powder (average primary particle size of the semiconductor powder: average primary particle size of the apatite powder) is in the range of 1: 2000 to 20: 1, and the weight composition ratio (purification) The weight of the said semiconductor powder per material unit volume: The weight of the said apatite powder) These powder is carry | supported by the base-material surface part so that it may become the range of 20: 80-95: 5. Production method. A method for producing a purification material having semiconductor particles having photocatalytic activity and apatite particles having photocatalytic activity on a substrate surface portion,
Preparing a semiconductor powder having photocatalytic activity and a substrate;
Preparing a slurry containing a raw material comprising at least calcium and phosphoric acid as constituent elements;
Mixing the semiconductor powder in the slurry and heat-treating at 150 to 300 ° C. in the presence of oxygen to obtain an apatite-supporting semiconductor powder;
A step of supporting the apatite-supporting semiconductor powder on the surface of the substrate;
Manufacturing method.   The manufacturing method in any one of Claims 6-9 which prepares the ceramic porous body which has a three-dimensional network structure as the said base material. The purification material according to any one of claims 1 to 5,
A light source for irradiating the purification material with ultraviolet rays;
A purification module comprising:   The purification module according to claim 11, wherein the light source generates ultraviolet light having a wavelength of 254 nm or less.

Images