JPH11290695A - Photocatalytic filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To emit a light sufficiently deep inside and thereby fully exhibit the photocatalytic performance of a deodorizing material as a whole by integrally combining an adsorbing material borne on the surface and the interior of a photocatalyst with a light waveguide path which guides an excited light to the photocatalyst to form a photocatalytic filter. SOLUTION: A microparticular powder of TiO2 is added to and dispersed in a silica sol prepared by dissolving a tetraethoxysilane in ethanol and adding a mixed solution of water, nitric acid and ethanol. Further, a fibrous activated carbon is soaked in this dispersion and is removed from the dispersion to be dried and baked and consequently, a TiO2 bearing fibrous activated carbon unwoven fabric 1 is obtained. A platelike filter comprising alternately laminated sheetlike light waveguide paths 2 consisting of a bundle of guarty fibers and the unwoven fabric 1, is built in a closed circulation-type gaseous phase reaction device. In addition, acetoaldehyde is circulated through the filter while ultraviolet rays are irradiated from the end face of the light waveguide paths 2. Thus, it is possible to efficiently emit an excited light from outside the filter to the inside photocatalyst, so that the performance of the photocatalyst can be fully exhibited.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photocatalyst filter used for an air purifier, a sewage treatment apparatus, a water purifier and the like. In recent years, attempts have been made to use photocatalysts for environmental purification such as air purification and sewage purification. It irradiates semiconductors such as titanium oxide (TiO ₂ ) with light having an energy greater than the energy gap, thereby oxidizing and reducing electrons and holes, causing odorous and harmful substances in the air and water. Decompose and remove. [0003] Since the photocatalytic reaction occurs only on the surface of the photocatalyst, in air purification and sewage purification using the photocatalyst, it is necessary to efficiently supply a treatment substance to the surface of the photocatalyst. Attempts have been made to use a photocatalyst carried on an adsorbent such as activated carbon to purify odorous substances in air and sewage. However, since the photocatalytic reaction occurs only in the area where light is illuminated, if the photocatalyst is supported by the adsorbent, the area where the light does not illuminate is created, and the performance of the photocatalyst cannot be fully exhibited. There is. [0004] As a deodorizing method using a photocatalyst having a high decomposition performance of malodorous substances, for example, in Japanese Patent Application Laid-Open No. 9-75434, an adsorbent made of a porous substance carrying titanium oxide is used.
There has been proposed a method of using a deodorant formed by adding at least one component selected from an ultraviolet sensitizer, a light-transmitting ceramic, and a light-transmitting plastic. This is one in which the irradiation efficiency of the excitation light to the titanium oxide is increased and the deodorizing performance is increased by using any of an ultraviolet sensitizer, a translucent ceramic, and a translucent plastic. [0005] Although the technique presented above is excellent, the adsorbent supporting titanium oxide is mixed with an ultraviolet sensitizer, translucent ceramics, and translucent plastics. Particles or powder, or molded into a plate or the like with a binder or an adhesive.Light can pass through to a certain depth from the surface of the deodorizing material, but each component is dispersed. There remains a problem that light cannot be irradiated to the inside of the deodorizing material due to its existence. Specifically, as an example, 100 g of coconut shell activated carbon supporting titanium oxide and p-
1 g of nitroaniline, 2 g of translucent alumina powder as translucent ceramic, and polyethylene powder binder 15
g is mixed and shaped into a plate.
Since the light-transmitting material that guides light into the inside is dispersed in powder and the volume of the whole is small, light cannot be sufficiently supplied to the inside, and the photocatalytic performance of the entire deodorizing material cannot be sufficiently exhibited. According to the present invention, a photocatalyst filter is formed by integrally combining an adsorbent carrying a photocatalyst on the surface or inside thereof and an optical waveguide capable of guiding excitation light of the photocatalyst. By doing so, it is possible to efficiently supply the excitation light irradiated from the outside of the filter to the photocatalyst inside the filter,
This realizes a photocatalyst filter having excellent performance of decomposing and removing processing substances. Needless to say, the photocatalytic filter is often used in combination with other components or structural materials such as a filter housing and an adhesive. The photocatalyst filter of the present invention is characterized in that an adsorbent carrying a photocatalyst on the surface or inside thereof and an optical waveguide capable of guiding excitation light of the photocatalyst are integrally combined.
In the present invention, the light emitted from the outside of the filter is guided to the inside of the filter by the optical waveguide, which is one of the constituent members of the filter. It can be fully exhibited and has excellent decomposition treatment performance for treated substances. In addition, the adsorbent used as the supporting substrate for the photocatalyst efficiently collects the treatment substance in the air or water and increases the probability of contact of the treatment substance with the photocatalyst surface.
Excellent processing performance. Even if the substance is difficult to be completely decomposed by the photocatalyst and easily produces an intermediate product, the adsorbent increases the probability of re-adsorbing the intermediate product and coming into contact with the photocatalyst surface. Since the treatment substance adsorbed on the adsorbent is completely decomposed by the photocatalyst, there is no performance deterioration due to adsorption saturation. As the adsorbent used as a supporting substrate for the photocatalyst in the present invention, any adsorbent can be used as long as it has an adsorbing property to the treatment substance. Activated charcoal, silica gel, activated alumina,
It is desirable to use zeolite or the like, and these may be used alone or in combination as necessary. It is important to select an optimal adsorbent according to the treatment substance. For example, activated carbon is preferably used for removing malodorous substances in the air and removing trihalomethanes, residual chlorine and mold odor in tap water. Activated carbon can be used in any form, such as granular, powdered, and fibrous. However, fibrous activated carbon has a large specific surface area and thus has excellent adsorption performance. This is most preferable because the filter shape can be easily manufactured. Raw materials for granular or powdered activated carbon include coconut shell, coal, coke, and charcoal, and raw materials for fibrous activated carbon include cellulosic fibers, phenolic fibers, and pitch-based fibers, all of which can be used. What is necessary is just to select a substance having excellent adsorption performance for the substance to be treated. For example, to remove trihalomethane from tap water, it is preferable to use a coconut shell material. Granular activated carbon, powdered activated carbon, silica gel,
The above-mentioned adsorbent such as activated alumina and zeolite can be easily formed into a sheet using a binder or the like. By combining these granular or powdery adsorbents with fibrous activated carbon, the function of the fibrous activated carbon can be improved. For example, fibrous activated carbon is combined with granular activated carbon as a coconut shell material to improve the performance of removing trihalomethanes in water. The photocatalyst used in the present invention is, for example, Ti
O ₂ , SrTiO ₃ , CdS, CdSe, GaP, ZrO ₂ , KTaO ₃ , KTa
_0.77 Nb _0.23 O ₃ , Nb ₂ O ₅ , ZnO, Fe ₂ O ₃ , WO ₃ , SnO ₂ , I
Any known substance having a photocatalytic ability, such as n ₂ O ₃ , MoO ₃ , Cu ₂ O, and CuFeO ₂ , can be used alone or in combination of a plurality of substances. In particular, TiO ₂ is particularly desirable because it has a strong oxidizing power and is inexpensive and harmless. TiO ₂ has two types of crystal structures, anatase type and rutile type, both of which can be used, but it is preferable to use an anatase type having higher catalytic activity. Alternatively, both may be used in combination. For the purpose of improving the photocatalytic performance, a metal such as Pt, Pd, Au, Ag, Ru, Rh, Fe, Co, Ni, Cu, Zn or an oxide of these metals may be used alone or in combination on the TiO ₂ surface. May be carried in combination. Especially Pt on TiO ₂ surface,
What carries fine particles of a noble metal such as Pd and Au having a particle size of 1 to 100 nm is particularly desirable because of its high photocatalytic performance as is known. Methods for supporting these metals or metal oxides on the TiO ₂ surface include impregnation, light deposition, chemical deposition, simultaneous precipitation, kneading, shaking, metal powder addition, vacuum evaporation, and sputtering. A known technique such as a method can be used. When using TiO ₂ carrying these metals or metal oxides, these materials were supported
The TiO ₂ fine particles may be supported on the adsorbent and used, or these materials may be supported and used after the TiO ₂ is supported on the adsorbent. The photocatalyst needs to be supported on the surface or inside of the adsorbent so as not to fill the pores of the adsorbent as much as possible. Known methods such as a sol-gel method, a thermal decomposition method, a pyrosol method, a CVD method, a vacuum deposition method, a sputtering method, an ion plating method, and a metal oxidation method can be used as a method for supporting the photocatalyst. The fine particles of the photocatalyst may be supported on the photocatalyst via a binder that is hardly decomposable. In this case, a known binder such as an inorganic binder such as silica or alumina, or an organic binder such as a fluorine-based polymer or a silicon-based polymer may be used. The smaller the particle diameter of the photocatalyst is, the smaller the particle diameter is. The higher the photocatalytic activity, the more desirable it is to have an average particle diameter of 1 to 500 nm. TiO ₂ fine particles having the above-described metal or metal oxide fine particles supported on the surface may be used. When the photocatalyst is TiO _2, a commercially available photocatalyst coating material containing an inorganic binder component may be used. As the optical waveguide used in the present invention, any waveguide can be used as long as it can guide light capable of exciting the photocatalyst. The shape may be selected depending on the adsorbent to be combined, such as a fiber shape, a sheet shape, a plate shape, and a cylindrical shape, so that the shape can be easily applied to a required filter shape. As a structure, for example, a structure including only a light guide portion such as a glass fiber or a structure for confining light in a light guide portion such as an optical fiber may be used. As the material of the light guide portion, that the transmittance of the excitation light of the photocatalyst as high as possible is desirable, when using a TiO ₂ photocatalyst, for example, quartz glass, borosilicate glass, alumina, the use of polycarbonate desired . As the optical waveguide, specifically, glass, translucent resin, translucent ceramic, or the like processed into a plate, sheet, or cylinder, glass fiber, quartz fiber, optical fiber, or the like can be used. In the optical waveguide used in the present invention, it is desirable that the light gradually leaks as the incident light propagates inside the filter. The optical waveguide including only the light guide section does not need to be specially devised. When using an optical fiber, for example, bend the optical fiber and install it in a filter, scrape a part of the cladding to expose the core, and use a lens etc. so that light is incident at an angle of incidence slightly larger than the maximum acceptance angle Adjustment may be performed. When an optical fiber is used, 1.3 μm
It is particularly desirable to use a single mode fiber for signal transmission used in optical communication such as a band, a 1.55 μm band, and a 0.85 μm band. In such a fiber, the cross-sectional area of the clad is very large compared to the cross-sectional area of the core.
By using the clad for transmitting light, a large amount of light can be transmitted. Further, since the light propagates while leaking appropriately, there is no need to control the incident angle of the light or to bend the optical fiber. In addition, since the material of the clad is quartz having a high transmittance from visible light to ultraviolet light,
Even when using a photocatalyst such as O ₂ that requires ultraviolet light for excitation light, it is possible to efficiently propagate ultraviolet light.
Furthermore, there is an advantage that it is manufactured in large quantities for optical communication and is very inexpensive. The songle mode fiber can use any fiber if the cladding is quartz glass. As the clad material, pure silica glass with good transmission characteristics from ultraviolet light to visible light is most desirable,
A material doped with an impurity such as fluorine can also be used. Any core material can be used, SiO ₂ + GeO ₂
Glass, quartz glass, and the like are easily available, but these materials may be doped with impurities. The cladding diameter is desirably 50 to 500 μm. A filter thinner than this is not suitable because the amount of light that can be transmitted is small and the intensity is weak, and a filter thicker than this is not suitable because it becomes difficult to bend when making a filter. In view of the amount of light that can be transmitted, the strength, the ease of bending, and the availability, it is more desirable that the thickness be 100 to 150 μm. The core diameter is desirably 1 to 25 μm. Thicker than this is difficult to fabricate, and thicker than this is not desirable because the cross-sectional area of the cladding is small and the amount of light that can propagate is small. 5 to 15 μm from ease of fabrication, size of clad cross-sectional area, and availability
Are more desirable. As such a single mode fiber, for example, a single mode fiber for 1.3 μm band,
Pure silica core fiber (cutoff shift fiber) for 1.55 μm band, dispersion shift fiber for 1.55 μm band, single mode fiber for 0.85 μm, etc., all of which can be used. The 1.3 μm band single mode fiber having a small value is most desirable because of good light propagation efficiency. The optical fiber core wire is usually coated with urethane acrylate or the like on the surface in order to secure the strength. Therefore, such a surface coating is removed before use. As a method of removing the surface coating,
For example, a method of dissolving with an acid such as sulfuric acid can be used. Next, the structure of the photocatalytic filter of the present invention will be described. The shape of the filter can be arbitrarily selected according to the shape of the device, such as a sheet, a plate, a cylinder, and a honeycomb. FIG. 1 shows an example of a plate filter in which the adsorbent is fibrous activated carbon formed in a sheet shape, and has a structure in which a fibrous activated carbon 1 supporting a photocatalyst and an optical waveguide 2 are stacked and combined. The sheet-like fibrous activated carbon includes non-woven fabric (felt-like), paper-like, and honeycomb-like ones. The figure shows an example in which a fiber-like material such as a glass fiber or an optical fiber is used for the optical waveguide 2. However, the present invention is not limited to the fiber shape, and any one of the above-described ones can be used. In the example shown in the figure, the excitation light is used from the upper surface of the filter where the end face of the fiber optical waveguide is exposed. FIG. 2A shows a fibrous activated carbon in which an adsorbent is formed in a sheet shape, and a sheet-shaped fibrous activated carbon 1 carrying a photocatalyst and an optical waveguide 2 are concentrically arranged and combined. 9 shows an example of a filter. FIG. 2B shows an example of a cylindrical filter in which a sheet-like fibrous activated carbon 1 supporting a photocatalyst and an optical waveguide 2 are wound in a multiple spiral. Although the figure shows an example in which a fiber-shaped optical waveguide is used, the present invention is not limited to the fiber-shaped one and can be selected from the above-mentioned ones. In the example shown in the figure, the excitation light is used from the upper surface of the filter where the end face of the fiber optical waveguide is exposed. FIG. 3A shows a fibrous activated carbon in which an adsorbent is spun into a long fiber, and a sheet formed by bundling a long fiber activated carbon 3 carrying a photocatalyst and a fiber optical waveguide 4 is shown in FIG. FIG. 3B shows a sheet formed by weaving a long fiber activated carbon carrying a photocatalyst and a fiber optical waveguide 4, and a plurality of these sheets are formed into a plate shape, or It is formed into a cylindrical shape by winding and used as a filter. The figure shows an example of how to bundle or knit a long fibrous fibrous activated carbon and a fibrous optical waveguide, and a sheet may be formed with another bundling or knitting method. These examples have a particularly desirable structure because fibrous activated carbon having high adsorption performance is used, excitation light irradiation efficiency is particularly excellent, and filter fabrication is easy. FIG. 4 shows a cylindrical filter in which cylindrical optical waveguides 5 are arranged concentrically and an adsorbent 6 carrying a photocatalyst is filled between the optical waveguides 5. In this filter, a hole 7 is formed in the side surface of the cylindrical waveguide so that the gas or liquid to be processed can flow from the hole at the center of the cylinder to the side of the cylinder or from the side of the cylinder toward the center of the cylinder. I have. What has been described above with reference to the drawings is only one example of the photocatalyst filter of the present invention. As described above, the photocatalyst filter has at least a structure in which an adsorbent supporting a photocatalyst and an optical waveguide are combined. Any structure can be used. The optical waveguide may extend to the outside of the filter, and may have a structure in which excitation light is incident from a place away from the filter. Further, in the above description, the production of the adsorbent supporting the photocatalyst and the optical waveguide may be performed by a known method, but it goes without saying that a new method that may be generated in the future may be used. Light having a wavelength that can excite the photocatalyst supported on the adsorbent can be used as light to be incident from the end face of the optical waveguide for the photocatalytic reaction. Examples of the light source include a discharge lamp such as a mercury lamp and a xenon lamp, and a fluorescent lamp. Lamps, black lights, fluorescent lamps such as germicidal lamps, filament lamps such as incandescent lamps, artificial light sources such as laser light sources, or
Sunlight can be used. The photocatalyst filter of the present invention can be used for treating gas or liquid by using it in combination with the light source for photocatalyst excitation described above. For example as a gas process, decompose and remove such malodorous substances or bacteria in the air, decomposing and removing harmful substances such as organic chlorine compounds in the exhaust gas, and the like oxidation removal of the NO _x in the atmosphere, as the processing liquid, drained Decomposition and removal of harmful substances such as organic chlorine compounds in water, decomposition and removal of harmful substances such as pesticides in groundwater, decomposition and removal of trihalomethanes, residual chlorine, moldy odor substances, bacteria, etc. in tap water, heavy metals in drainage and tap water It can be used for removing ions. Can also be used in such as H ₂ generated by photolysis of water photolysis and water. Embodiments of the present invention will be described in detail with reference to the following examples. EXAMPLE 1 Non-woven fibrous activated carbon was used as an adsorbent and used as a photocatalyst.
TiO ₂ was loaded as follows. First, 100 g of tetraethoxysilane is dissolved in 1000 ml of ethanol,
A silica sol was prepared by adding 500 ml of a solution obtained by mixing water, nitric acid and ethanol at a molar ratio of 1: 20: 100.
This is followed by an anatase type TiO ₂ fine particle powder (Ishihara Sangyo, S
T-01) was added and dispersed, and fibrous activated carbon was immersed, pulled up and dried, and then baked at 400 ° C. for 1 hour to obtain a TiO ₂ -supported fibrous activated carbon nonwoven fabric. A quartz fiber having a diameter of 100 μm is used as an optical waveguide, and a bundle of the fibers and a sheet-like fiber and a TiO ₂ -supported fibrous activated carbon nonwoven fabric are alternately laminated to form a 35 cm width and a length 3 having the structure of FIG.
A plate-like filter having a thickness of 0 cm and a thickness of 5 mm was prepared. This filter was assembled in a closed-circulation type gas phase reactor, and irradiated with ultraviolet light from above the filter using a 10 W black light fluorescent lamp so that light was incident from the end face of the quartz fiber. A diluted initial concentration of 100 ppm acetaldehyde was circulated through the filter. The time-dependent change in the concentration of acetaldehyde after the start of light irradiation was measured by gas chromatography.
After time, the acetaldehyde concentration decreased to 1 ppm. The above operation was repeated 10 times, but the ability to remove acetaldehyde did not change. Example 2 A TiO ₂ -supported fibrous activated carbon nonwoven fabric produced in the same manner as in Example 1 and a sheet formed by bundling quartz fibers having a diameter of 100 μm were stacked, and this was spirally wound.
A cylindrical filter having an inner diameter of 3 cm, an outer diameter of 5 cm, and a length of 30 cm having the structure of (b) was produced. The filter was assembled in a closed circulation type liquid phase reaction apparatus, and irradiated with ultraviolet light from above the filter using a 10 W black light fluorescent lamp so that light was incident from the end face of the quartz fiber. 1 ppm of 2
-Treated water containing methyl isoborneol was circulated through the filter. The treated water was allowed to flow through the center hole of the cylinder, through the cylinder, and to the outside from the side surface of the cylinder. The time-dependent change in the concentration of 2-methylisoborneol after the start of light irradiation was measured by a gas chromatograph mass spectrometer. As a result, after 30 minutes, the concentration of 2-methylisoborneol was reduced to 0.01 ppm. The above operation was repeated 20 times, but the removal ability of 2-methylisoborneol did not change. If necessary, it may be formed in a cylindrical shape as shown in FIG. 2A without being spirally wound. Example 3 Using fibrous activated carbon spun into long fibers as an adsorbent, TiO ₂ was carried in the same manner as in Example 1 to obtain TiO ₂ -supported long fibrous activated carbon. The core whose surface coating was removed with a 10% aqueous hydrogen sulfide solution as an optical waveguide was SiO ₂ + GeO ₂ glass having a diameter of 8 μm.
The cladding is a single-mode fiber of 1.3 μm band with a diameter of 125 μm of quartz glass (manufactured by Sumitomo Electric Industries, product number: ES
Using -1), a single-mode fiber was woven into the warp and a TiO ₂ -supported fibrous activated carbon filament was used as the weft in a lattice pattern to form a sheet having the structure shown in FIG. 3B. This sheet is wound so that the single mode fiber is in the longitudinal direction of the filter, and the inner diameter is 3 cm, the outer diameter is 5 cm, and the length is 30 cm.
Was manufactured. The filter was assembled in a closed-circulation liquid-phase reactor, and irradiated with ultraviolet light from above the filter using a 10 W black light fluorescent lamp so that light was incident from the end face of the quartz fiber. Treated water containing 1 ppm of trichloroethane was circulated through the filter. The treated water was allowed to flow through the center hole of the cylinder, through the cylinder, and to the outside from the side surface of the cylinder. The time-dependent change of the trichloroethane concentration after the start of the light irradiation was measured by gas chromatography, and after 30 minutes, the trichloroethane concentration was reduced to 0.02 ppm. The above operation was repeated 20 times, but the ability to remove trichloroethane did not change. In addition, if necessary, the warp and the weft may not be woven in a lattice shape, but may be used by being arranged side by side as shown in FIG. Example 4 Activated TiO ₂ was carried out in the same manner as in Example 1 using granular coconut shell activated carbon having a standard particle size of 50 mesh as an adsorbent to obtain TiO ₂ -supported granular activated carbon. Thickness with a hole on the side as an optical waveguide 2
A cylindrical quartz glass having a length of 30 mm and a length of 30 mm was used. The optical waveguide has an inner diameter of 3 cm, 3.5 cm, 4 cm, 4.5 cm, and 5 cm.
One having an inner diameter of 5 cm and having a bottom was used. These were arranged concentrically and TiO ₂ -supported granular activated carbon was filled between the optical waveguides to produce a cylindrical filter having the structure of FIG. This filter was assembled in a closed-circulation liquid-phase reactor, and irradiated with ultraviolet light from above the filter using a 10 W black light fluorescent lamp so that light was incident from the end face of the quartz glass waveguide. Initial concentration 1ppm
Processed water containing chloroform was circulated through the filter. The treated water was allowed to flow through the center hole of the cylinder, through the cylinder, and to the outside from the side surface of the cylinder. The change with time of the chloroform concentration after the start of light irradiation was measured by a gas chromatograph mass spectrometer, and the chloroform concentration was reduced to 0.01 ppm after 30 minutes. Perform the above operations 2
Although repeated 0 times, the ability to remove chloroform did not change. Example 5 Silica gel having an average particle size of 6 mesh was used as an adsorbent, and TiO ₂ was supported by a sol-gel method. As a procedure of the sol-gel method, first, 150 ml of an isopropanol solution of 80% by weight of titanium tetraisopropoxide is added to 750 ml of pure water and 5 ml of nitric acid, and a titania sol is prepared by hydrolysis.
After dip-coating silica gel with titania sol, 5
Calcination was performed at 50 ° C. to obtain TiO ₂ -supported silica gel. A cylindrical filter similar to that of Example 4 was produced using the same cylindrical quartz glass as the optical waveguide and TiO ₂ -supported silica gel instead of the photocatalyst-supported granular activated carbon. This filter was incorporated in a closed-circulation type gas phase reactor, and irradiated with ultraviolet light using a 10 W black light fluorescent lamp from the top of the filter so that light was incident from the end face of the quartz glass waveguide. A 100 ppm initial concentration of tetrachloroethylene diluted with air was circulated through the filter. The gas was circulated so as to pass through the center hole of the cylinder, pass through the cylinder, and escape from the side of the cylinder to the outside. The change with time of the tetrachloroethylene concentration after the start of the light irradiation was measured by gas chromatography, and after 2 hours, the tetrachloroethylene concentration was reduced to 5 ppm. The above operation was repeated 10 times, but the ability to remove tetrachloroethylene did not change. As described above, the use of the photocatalytic filter of the present invention makes it possible to efficiently decompose and remove malodorous substances and harmful substances in the gas phase and in water. Since the light is efficiently irradiated over the entire filter by the optical waveguide, the processing capacity is high, and the substance adsorbed by the adsorbent inside the filter is also efficiently decomposed, so that the removal performance does not deteriorate even if the reaction is repeated. As described above, according to the present invention, the excitation light radiated from the outside of the filter can be efficiently supplied to the photocatalyst inside the filter, and the photocatalyst excellent in the decomposition and removal performance of the processing substance can be obtained. A filter can be realized.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view illustrating a configuration of a photocatalytic filter according to a first embodiment. FIGS. 2A and 2B are perspective views illustrating the configuration of a photocatalytic filter according to a second embodiment. FIGS. 3A and 3B are plan views illustrating the configuration of a photocatalytic filter according to a third embodiment. FIG. 4 is a perspective view illustrating a configuration of a photocatalytic filter according to a fourth embodiment. DESCRIPTION OF THE SYMBOLS 1 Fibrous activated carbon carrying photocatalyst 2 Optical waveguide 3 Long fibrous activated carbon carrying photocatalyst 4 Fiber optical waveguide 5 Cylindrical optical waveguide 6 Adsorbent carrying photocatalyst 7 Cylindrical optical waveguide Hole on the side

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI C02F 1/32 C02F 1/72 101 1/72 101 F24F 7/00 A // F24F 7/00 B01D 53/36 ZABJ

Claims (1)

Claims: 1. A filter is formed by integrally combining an adsorbent carrying at least a photocatalyst on the surface or inside thereof and an optical waveguide capable of guiding excitation light of the photocatalyst. A photocatalyst filter, wherein excitation light irradiated from the filter is supplied to a photocatalyst inside the filter by an optical waveguide. 2. The photocatalyst filter according to claim 1, wherein the adsorbent is made of one or a combination of activated carbon, silica gel, activated alumina and zeolite. 3. The photocatalytic filter according to claim 1, wherein the adsorbent is formed in a sheet shape, and has a plate shape in which the sheet-shaped adsorbent and the optical waveguide are laminated. 4. The adsorbent is formed in a sheet shape and the sheet-shaped adsorbent and the optical waveguide are formed in a concentric circular cylindrical shape, or the sheet-shaped adsorbent and the optical waveguide are formed in a multiple spiral shape. The photocatalyst filter according to claim 1 or 2, wherein the photocatalyst filter has a wound cylindrical shape. 5. The adsorbent is spun into a long fiber, the optical waveguide is formed into a fiber, and both are bundled or braided to form a sheet, or the sheet is cylindrical or multi-layered. The photocatalyst filter according to claim 1 or 2, wherein the photocatalyst filter is formed in a spiral shape. 6. The photocatalyst filter according to claim 1, wherein the optical waveguide is a single mode fiber for optical communication. 7. The photocatalyst filter according to claim 1, wherein the photocatalyst is titanium oxide.