JPH0847687A - Water purifier - Google Patents

Abstract

PURPOSE:To conveniently and efficiently exterminate the harmful organism such as algae, to decompose harmful matter and to purify water by providing a water purifier with a photocatalyst, a fixed-bed photocatalyst reactor, a means for supplying water to the reactor and a means for irradiating the photocatalyst with a UV-contg. light and cascade-controlling the water current. CONSTITUTION:A photocatalyst A consisting of a filler carrying titanium oxide is arranged at the bottom of a fixed-bed photocatalyst reactor 1, white fluorescent lamp 2 is set above the reactor 1, and a pump 3 is installed to supply water to the reactor 1. This water purifier 1 is placed above a water tank 4, water in the tank 4 is introduced into the purifier, the water is fed back, and the water current is cascade-controlled. Titanium oxide as the photocatalyst is deposited on a light-transmissive filler to obtain the photocatalyst A, and a light selected from a group consisting of sunlight, florescent lamp, black lamp, sterilizing lamp, mercury lamp incandescent lamp is used as the light contg. UV.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water purification device,
More specifically, the present invention relates to a water purification device that utilizes the photocatalytic function of titanium oxide.

[0002]

2. Description of the Related Art Some domestic wastewater, irrigation wastewater, and industrial wastewater contain a large amount of substances such as nitrogen and phosphorus, which cause eutrophication in lakes, marshes, rivers, and sea bays. When algae such as plankton, picoplankton, water-bloom, and red-crown grow due to eutrophication, water becomes musty due to odorous substances such as holmium, which is a type of plankton, or 2-methylisoborneol, which is an odor substance produced by oscillatria. It has a bad influence on water supply or forms so-called water flower, freshwater blue tide or freshwater red tide, which colors lake or river water green or brown, or so-called red tide, which colors seawater reddish brown, pink or brown. , Which damages the landscape, digests oxygen in the water to cause oxygen deficiency, and causes plankton to adhere to the gills of fish, causing respiratory distress, which causes great damage to fisheries. In addition, the algae that have multiplied may impede water purification treatment by, for example, pinching filter ponds and filtration screens in water purification plants and dams. In addition, domestic wastewater, irrigation wastewater, or industrial wastewater contains fungi such as molds, fungi such as actinomycetes, and bacteria such as Escherichia coli, which may multiply in lakes, marshes, rivers, sea bays, and the like. Fungi include harmful diseases such as infectious disease bacteria such as typhoid fever and Shigella, sulfur bacteria that promote corrosion, iron bacteria, sulfate-reducing bacteria, slime-producing bacteria and fungi, and actinomycetes that smell water. Not a few, various types of damage have occurred.
Especially, in the ponds and aquariums where fish, shellfish, crabs, shrimp, frogs, etc. are cultivated, and in the ornamental ponds and aquariums where fish etc. are raised, the water is contaminated by excrement and food spoilage. , Foul odors are emitted, and excrements, spoilage of foods, etc. frequently cause damages caused by bacteria and fungi. In addition to the above, domestic wastewater, irrigation wastewater, or industrial wastewater may contain oxygen-requiring substances such as detergents and oils, and harmful substances such as organic halogen compounds and pesticides contained in the wastewater of semiconductor manufacturing plants. , May pollute lakes, rivers, sea bays and cause damage to living things.

In order to kill or sterilize the algae, fungi, and bacteria that have grown, for example, a method of injecting chlorine, ozone, copper sulfate, or the like, or a method of treating by irradiation with ultraviolet rays is adopted. To remove odorous substances and coloring substances generated by algae, fungi and bacteria, use
The method of adsorbing on activated carbon is adopted. In particular,
At water purification plants that take water from polluted lakes and rivers, a large amount of activated carbon is administered to improve water quality. on the other hand,
When titanium oxide is irradiated with light having a wavelength having energy higher than its band gap, photoexcitation causes electrons to be generated in the conduction band,
Although holes are generated in the valence band, there has been proposed a method of sterilizing, decomposing or deodorizing an organic substance by utilizing the strong reducing power of the electrons generated by the photoexcitation and the strong oxidizing power of the holes.

[0004]

Although the above-mentioned method of treating with chlorine or ozone can reduce algae, fungi, and bacteria, its effect is not sufficient, and the treatment time is long, There is a problem that the drug used and the compound generated from the drug remain in water. The activated carbon adsorption method can reduce odor and coloring, but
It does not kill fungi and bacteria. The titanium oxide photocatalyst method is expected to have a wide range of water purification effects such as killing of algae and fungi, decomposition of dead algae, fungi and dissolved organic substances, oxidation of ammonia, deodorization, etc. In order to improve the utilization efficiency and obtain a high photocatalytic function, the treatment is usually performed in a state where ultrafine particles of titanium oxide are individually dispersed. For this reason, it is necessary to separate and recover titanium oxide from the treatment system, but this separation and recovery operation may be extremely difficult, making it difficult to put it into practical use.

[0005]

[Means for Solving the Problems] The present inventors focused on the photocatalytic function of titanium oxide and simply and efficiently killed harmful organisms such as algae, fungi, and bacteria contained in water, and As a result of various studies on methods for decomposing substances to purify water, (1) water was sent to a fixed-bed photocatalytic reactor in which titanium oxide was placed, and light containing ultraviolet rays was generated in the fixed-bed photocatalytic reactor. Surprisingly, if water is treated while controlling the flow of water in the presence of water, algae killing, sterilizing, deodorizing, decolorizing or decomposing harmful substances can be performed efficiently, and water can be purified. , The purification of water is performed easily and easily because there is no need to collect it. (2) The concentration of the object to be treated contained in the water discharged from the fixed bed photocatalytic reactor is measured, and the result is Controllers such as liquid transfer means and light source It is possible to purify water more advanced by feedback control. (3) When titanium oxide is carried on the surface of the filler, the contact between titanium oxide, which is a photocatalyst, and the treated water becomes good, and algae in the treated water , Enhancement of purification action by killing bacteria and decomposition of harmful organic substances, (4) by loading a titanium oxide-supported packing material into a fixed bed reactor in order to control the water flow in a cascade, The contact between titanium oxide and treated water is improved, and the purifying action by killing algae and bacteria in the treated water and decomposing harmful organic substances is further improved. Furthermore, (5) for cascade control of water flow ,
It is possible to maintain and control a constant residence time by dividing the packed bed into multiple stages in the apparatus, and more preferably, by feeding back a part of the treated water in each stage or the whole to the preceding stage. The object to be processed can be efficiently processed up to a target processing concentration. (6) In particular, the filling material is a light transmissive material having a light transmittance of 50% or more, and 2 A combination of fillers of different sizes or more is used to support titanium oxide on the surface of the fillers to be used as a photocatalyst to increase the packing density, and the packed layer of the photocatalyst is irradiated with light having a thickness of 50 mm or less in the light entrance direction. By so doing, it is possible to further improve the contact between light and water on the photocatalyst, (7) In particular, algae, fungi, and bacteria are easily proliferated, and (a) Water in water storage tanks such as storage tanks. , Solar energy Water in water supply / hot water supply equipment and air conditioning equipment using ghee, bath water, pool water, domestic water such as tap water, drinking water, industrial water, agricultural water or raw water used for these water, (b) Water in the aquatic animal rearing area, and further (c) domestic wastewater, industrial wastewater from manufacturing, agriculture, fisheries, sewage treatment plant wastewater, pesticide-contaminated wastewater from golf courses, etc. (d) closure Waters, bays, lakes,
It was found that it is optimal for cleaning polluted water such as swamps, dams, scenic ponds, and viewing ponds. Based on these findings, the present inventors have further studied and completed the present invention.

That is, the present invention relates to a photocatalyst body made of titanium oxide, a fixed-bed photocatalyst reactor in which the photocatalyst body is arranged,
A water purification apparatus and a water purification method comprising: a means for sending water to the reactor; and a means for irradiating the photocatalyst with light containing ultraviolet rays, and performing cascade control of the water flow.

The present invention is to provide an apparatus and method for purifying water simply and efficiently.

In the present invention, the photocatalytic reactor is preferably a fixed bed, and the reactor such as a fluidized bed is not desirable because it requires a separation operation of titanium oxide. As the fixed bed photocatalytic reactor, for example, a fixed bed reactor, a radial flow type reactor, a parallel passage type reactor, a monolith type reactor, a thin layer type reactor, a tube wall type reactor and the like are used. A photocatalyst body made of titanium oxide is placed in the fixed bed photocatalytic reactor. The fixed-bed reactor is connected to the series, the inside of the fixed-bed reactor is divided into multiple stages, and a part of the treated water of each stage or the whole system is fed back to the previous stage. Is more preferable. In this case, a molded product of titanium oxide, which is a photocatalyst, can be arranged inside the fixed bed reactor, or titanium oxide can be arranged by adhering it to a filler, a wall surface inside the reactor, a metal net, or the like. In particular, it is preferable to attach titanium oxide to the surface of the filler. As the filler, various materials such as inorganic materials, metal materials, and organic materials can be used, and minerals such as stones can also be used. Desirable materials include various glasses such as light-transmissive quartz and quartz glass, soda lime glass, lead glass, aluminoborosilicate glass, borosilicate glass, and aluminosilicate glass, and various plastics. It is desirable to use a material that transmits 50% or more, preferably 70% or more of the light component to be transmitted. When such a light-transmissive filler is used, the irradiation light can be used more efficiently and the photocatalytic function can be further exerted. The filler is preferably suitable for cascading water flow. Cascade control of water flow means that the surface of the photocatalyst in the fixed bed photocatalyst reactor is irradiated with light and the treated water is brought into contact with the surface so that the contact surface is as wide as possible and the residence time is kept constant. Therefore, the flow of water is controlled in multiple stages, and more preferably, a part of the treated water is fed back. Fillers suitable for cascade control of water include various shapes such as Raschig rings, Lessing rings, Berlu saddles, Interlocks saddles, terrarettes, and pole rings, as well as amorphous shapes, spherical shapes, and plate shapes. A suitable size of the filler is about 100 μm to 5 cm in diameter, preferably 0.1 to 3 cm, and more preferably 0.2 to 2 cm. In the present invention, the thickness of the photocatalyst is set to 50 mm or less, preferably 40 mm or less, and more preferably 30 mm or less in the entrance direction of the irradiated light so that the entire photocatalyst is irradiated with the light. In order to adjust the thickness of the photocatalyst body to the above range, the number of light sources for irradiating light can be increased, or the light sources can be installed in a fixed bed photocatalytic reactor.

In the present invention, the titanium oxide used as the photocatalyst includes, in addition to titanium oxide, those generally called hydrous titanium oxide, hydrated titanium oxide, metatitanic acid, orthotitanic acid, titanium hydroxide, and the like. The crystal form does not matter. The above-mentioned titanium oxide can be obtained by various known methods. For example, a method of hydrolyzing a titanium compound such as titanyl sulfate, titanium chloride, or an organotitanium compound in the presence of seeds for nucleation, if necessary, and titanyl sulfate in the presence of seeds for formation of nucleation, if necessary. , A method of neutralizing by adding an alkali to a titanium compound such as titanium chloride or an organic titanium compound, a method of vapor-phase oxidizing titanium chloride or an organic titanium compound, a method of firing the titanium oxide obtained by the above method Is mentioned. In particular, titanium oxide obtained by the above method is preferable because of its high photocatalytic function. In order to improve the photocatalytic function of titanium oxide, platinum, gold, silver,
A metal such as copper, palladium, rhodium, or ruthenium, or a metal oxide such as ruthenium oxide or nickel oxide may be coated. The titanium oxide thus obtained is suspended in a solvent such as water, alcohol or toluene. Various dispersants and binders may be added as needed. The obtained suspension is applied, for example, by an impregnation method, a dip coating method, a spinner coating method, a blade coating method, a roller coating method, a wire bar coating method, a reverse roll coating method, or a spraying method. Etc., is used to apply or spray to the surface of the filler, the wall surface in the reactor, the wire mesh, etc., and then dried to deposit titanium oxide. In particular, it is preferable to highly disperse the titanium oxide obtained by the above method in a solvent to form a titanium oxide sol, and to apply or spray the titanium oxide sol. The adhering titanium oxide may be fired if necessary, and by this firing, the titanium oxide can be firmly adhered to the surface of the filler, the wall surface in the reactor, the wire netting and the like. The above-mentioned firing is 100 ° C. or higher, preferably 200
It is suitable to bake at a temperature of ˜800 ° C., particularly preferably 300˜800 ° C. In addition, the above-mentioned titanyl sulfate,
By hydrolyzing or neutralizing titanium chloride, an organic titanium compound or the like in the presence of the filler, depositing and adhering titanium oxide on the surface of the filler, then drying, and further firing if necessary. Also, titanium oxide can be supported on the filler.

The present invention comprises means for feeding water to be treated to a fixed bed photocatalytic reactor under pressure, reduced pressure or atmospheric pressure. Usually, it is preferable to use a pump or gravity to send the liquid, and as a means for circulating the liquid in the apparatus, a method such as a spontaneous drop by the pump or gravity is preferable. Furthermore, a means for irradiating the photocatalyst made of titanium oxide in the fixed-bed photocatalytic reactor with light containing ultraviolet rays is provided, and water is purified in the fixed-bed photocatalytic reactor in the presence of light containing ultraviolet rays. . Examples of the light containing ultraviolet rays include sunlight, fluorescent lamps, black lights, halogen lamps, xenon flash lamps, germicidal lamps, mercury lamps and incandescent lamps. Especially 300-400n
Light containing m near-ultraviolet rays is preferred. The irradiation amount and irradiation time of the light containing ultraviolet rays can be appropriately set depending on the degree of contamination of the water to be treated and the content of ultraviolet rays. The fixed bed photocatalytic reactor used in the present invention may have the form of the reactor used in Examples 1 to 6 described later, or may be appropriately modified, or two or more reactors may be connected and used. good.

The purifying device of the present invention may further comprise means for feedback control. In the present invention, the feedback control is to measure the concentration of the object to be treated contained in the water discharged from the fixed bed photocatalytic reactor, and feed back the result to a controller such as a liquid feeding means or a light source, and the controller gives It is a method that determines the next operation by comparing the obtained target with the measurement result. If the measurement result is a concentration higher than the target, an operation is performed to reduce the liquid supply amount or increase the light irradiation amount to bring the concentration close to the target. These operations can be controlled using a computer.

Using the purifying apparatus of the present invention, water is sent to a fixed-bed photocatalytic reactor using titanium oxide as a photocatalyst,
Water can be purified in the fixed bed photocatalytic reactor by irradiating the titanium oxide with light containing ultraviolet rays.

[0013]

EXAMPLES Examples of the present invention will be shown below, but the present invention is not limited thereto. Example 1 An acidic titania sol (CS-C, manufactured by Ishihara Sangyo Co., Ltd.) obtained by hydrolyzing titanyl sulfate was heated to 40 on a TiO ₂ basis.
Diluted with water to g / l. Next, the diluting solution was impregnated with a filler of glass beads (diameter 1 cm) having a spherical shape and a light transmittance of 85% and having a light transmitting property for 2 hours, and then ammonia water was added thereto. It was neutralized to pH 7 and titanium oxide was attached to the surface of the filler. Subsequently, the filler to which titanium oxide is attached is separated by filtration, dried, and then dried in the air at 600
It was baked at a temperature of ° C for 2 hours. Next, the baked filler was washed with water and dried to obtain a photocatalyst A. The amount of titanium oxide supported on the photocatalyst A was 1.
It was 6 parts by weight. As shown in FIG. 1, 300 g of this photocatalyst A was placed on the floor of the container so that the packed bed had a thickness of 30 mm in the entrance direction of the irradiation light, to obtain a fixed bed photocatalytic reactor 1. 15c above this fixed bed photocatalytic reactor
A white fluorescent lamp 2 of 20 W was installed at a distance of m, and a pump 3 for feeding water to the fixed bed photocatalytic reactor was further provided, and the purification device of the present invention was obtained. Aquarium 4 with 20 goldfish
This purification device was placed on (50 liters of water), the water in the water tank was sent to the purification device, and the water was fed back to examine the occurrence of phytoplankton and the contamination of the water. The water flow was cascade controlled. The water flow rate of the pump was 10 liters / minute. 0.5 g of food was administered to this aquarium twice a day. As a result, no phytoplankton was observed in this aquarium even after 2 weeks. Also,
When the number of viable bacteria and the number of coliforms in water 4 weeks after the start of the test were examined by the following method, the viable count was 6620 / ml and the coliform count was 3640 / ml. Compared with the above, the growth of fungi and bacteria could be suppressed. Further, as shown in Table 1, the change in water transmittance was smaller than that in Comparative Example 1, and there was almost no water stain.

<Method for measuring the number of viable bacteria and coliforms> The collected water is diluted 10 times or 100 times with sterile water, dispensed in 1 ml aliquots on 5 sterilized petri dishes, and then the medium is diluted to 10 m.
After adding, stirring and culturing at 37 ° C. overnight, the next day,
The number of colonies was counted. <Medium used> Number of viable bacteria: Brain Heart Infusion Bouillon (Nissui) Number of coliforms: Desoxycholate medium (Nissui)

Comparative Example 1 50 liters of water was placed in a water tank, 20 goldfish were bred, and phytoplankton generation and water stains were observed in the same manner as in Example 1. As a result, after 2 weeks, a large amount of phytoplankton was generated in the aquarium and the opposite side of the aquarium was contaminated so that it could not be seen. Further, when the number of viable bacteria and the number of coliforms in water 4 weeks after the start of the test were examined by the same method as in Example 1, the viable count was 8000 / ml and the coliform count was 4700 / ml. It was Further, as shown in Table 1, the change in the water transmittance was large, and the water was contaminated.

[0016]

[Table 1]

Example 2 400 g / l acidic titania sol based on TiO ₂ obtained by heating and hydrolyzing titanyl sulfate (manufactured by Ishihara Sangyo Co., Ltd.)
CS-C) was impregnated with a filler of spherical glass beads (diameter 1 cm) having a light transmittance of 65% for 2 days, and then the filler was separated by filtration. Dried
Titanium oxide was attached to the surface of the filler. Subsequently, the filler to which titanium oxide was attached was fired in the atmosphere at a temperature of 600 ° C. for 2 hours. Then, the fired filler was washed with water and dried to obtain a photocatalyst B. The amount of titanium oxide supported on this photocatalyst B was 3.6 parts by weight with respect to 100 parts by weight of the filler. 300 g of this photocatalyst B was placed on the floor of the container so that the packed bed had a thickness of 50 mm in the entrance direction of the irradiation light, to obtain a fixed bed photocatalytic reactor. A black light was installed above the fixed-bed photocatalytic reactor, and a pump for feeding water to the fixed-bed photocatalytic reactor was further provided to provide the purification apparatus of the present invention. In the present purifier, the intensity of ultraviolet light was 1.55 mW / cm ^{2 on} the surface of the filling material, and the water flow rate of the pump was 10 liters / minute. The purification device is placed next to the aquarium containing 50 liters of water from Lake Biwa used for daily life, and the water in the aquarium is sent to the purification device.
Water was fed back to examine the change in the concentration of 2-methylisoborneol, which is a musty odor component. The water flow was cascade controlled. The results are shown in Table 2. Most humans do not feel a musty odor when the concentration of 2-methylisoborneol is 10 ppt or less. When the domestic wastewater was treated in the same manner using the above-mentioned purification device, the organic matter contained in the domestic wastewater was decomposed and the COD value was lowered.

[0018]

[Table 2]

Example 3 1 kg of the photocatalyst B of Example 2 was used as shown in FIG.
Fixed bed photocatalytic reactor 5 filled in a donut type cylindrical container
And The thickness of the packed layer of the photocatalyst was 50 mm in the entrance direction of the irradiation light. This fixed-bed photocatalytic reactor is provided with a black light 6 inside, a mirror is attached to the inner wall surface, and a pump 7 for feeding water to the fixed-bed photocatalytic reactor is provided to purify the present invention. The device. In this purification device, the intensity of ultraviolet light was 1.55 mW / cm ^{2 on the} inner surface of the fixed bed photocatalytic reactor, and the water flow rate of the pump was 1
It was set to 0 liter / min, and a part of the discharged water was fed back. The water flow was cascade controlled. The same water of Lake Biwa as used in Example 2 was fed from above the purification device, and the concentration of 2-methylisoborneol after passing through the purification device was examined. As a result, the concentration of 2-methylisoborneol was 10 ppt or less.

Example 4 As shown in FIG. 3, the photocatalyst A of Example 1 was placed in a container divided into multiple stages so as to have a packed bed thickness of 50 mm, and the fixed bed photocatalytic reactor 8 was used. And A black light 9 of 10 W was installed at a distance of 15 cm above the fixed-bed photocatalytic reactor, and a pump 10 for feeding water to the fixed-bed photocatalytic reactor was further provided, and the purification device of the present invention was obtained. This device was placed on an aquarium 11 (50 liters of water) in which 20 goldfish were bred, the water in the aquarium was sent to a purification device, and the water was fed back to examine the change in COD. The water flow rate of the pump was 10 liters / minute. 0.5 g of food was administered to this aquarium twice a day. The water flow was cascade controlled. As a result, as shown in Table 3, it was confirmed that the COD was suppressed to be lower than that in Comparative Example 2 below, and the organic matter was efficiently decomposed.

Example 5 Acidic titania sol (CS-C manufactured by Ishihara Sangyo) obtained by hydrolyzing titanyl sulfate was 40 g / l based on TiO _2.
Diluted with water. Next, this diluting solution was impregnated with a filler of glass balls (diameter 0.5 cm) having a spherical shape and a light transmittance of 60% and having a light transmitting property for 2 hours, and then ammonia water was added. It was neutralized to pH 7 and titanium oxide was supported on the surface of the filler. Subsequently, the filler supporting titanium oxide was separated by filtration, dried, and then fired in the atmosphere at a temperature of 600 ° C. for 2 hours. Next, the baked filler was washed with water and dried to obtain a photocatalyst E. The amount of titanium oxide supported on this photocatalyst E was 2.5 parts by weight with respect to 100 parts by weight of the filler. This photocatalyst E and the photocatalyst A of Example 1 were mixed in the same volume, and the mixture was placed in the container used in Example 4 so that the packed bed had a thickness of 50 mm to obtain a fixed bed photocatalytic reactor. A black light of 10 W was installed at a distance of 15 cm above the fixed-bed photocatalytic reactor, and a pump for feeding water to the fixed-bed photocatalytic reactor was further provided, and the purification device of the present invention was obtained. This device was placed on an aquarium (50 liters of water) in which 20 goldfish were bred, the water in the aquarium was sent to a purification device, and the water was fed back to examine the change in COD. The water flow rate of the pump was 10 liters / minute.
0.5 g of food was administered to this aquarium twice a day. The water flow was cascade controlled. As a result, as shown in Table 3, it was confirmed that the COD was suppressed to be lower than that in Comparative Example 2 below, and the organic matter was efficiently decomposed.

Comparative Example 2 The floor of the container used in Example 1 was filled with a commercially available plastic filter cotton to a thickness of 50 mm. 15 cm above this container
A black light of 10 W was installed at a distance of, and a pump for feeding water was further provided in this container to provide a purification device for comparison. This device was placed on an aquarium (50 liters of water) in which 20 goldfish were bred, the water in the aquarium was sent to a purification device, and the water was fed back to examine the change in COD.
The water flow rate of the pump was 10 liters / minute. 0.5 g of food was administered to this aquarium twice a day. As a result,
As shown in Table 3, it was confirmed that COD increased in a short period of time and organic substances accumulated.

[0023]

[Table 3]

Example 6 The purification apparatus described in Example 3 was equipped with means for feedback control. That is, the concentration of 2-methylisoborneol contained in the water discharged from this purification apparatus was measured, and based on the result, the pumped liquid flow rate was in the range of 5 to 20 liters / minute, and the light source output power was adjusted. The intensity of ultraviolet light was controlled to be ¹ to 4 mW / cm ² . As a result,
The concentration of 2-methylisoborneol could be controlled to 5 ppt or less.

[0025]

INDUSTRIAL APPLICABILITY According to the present invention, a photocatalyst body made of titanium oxide, a fixed bed photocatalytic reactor in which the photocatalyst body is arranged, a means for feeding water to the reactor, and a light containing ultraviolet rays are applied to the titanium oxide. And a means for purifying water that cascade-controls the flow of water, wherein the photocatalytic function of titanium oxide kills harmful organisms such as algae, fungi, and bacteria contained in water, decomposes harmful substances, Furthermore, since deodorization and decolorization can be performed quickly and efficiently, it is extremely useful as a water purification device for not only industrial use but also general household use. In particular, it is possible to sterilize pathogenic bacteria such as Ogusale's disease and Hakuhan's disease that occur in a feeding area of fish and the like, and prevent the death of fish and the like. Since the purification apparatus of the present invention uses titanium oxide, it is highly safe, has a wide range of applicable harmful substances, and does not pollute the environment even if it is discarded, and thus is extremely useful industrially. Furthermore, the purification device of the present invention,
In order to control the water flow in cascade, a packing material carrying titanium oxide, which is a photocatalyst, is loaded into a fixed bed reactor,
Alternatively, the inside of the fixed bed reactor is divided into multiple stages, or individual fixed bed reactors are connected in multiple stages, and even more preferably,
By feeding back the treated water to the previous stage,
The contact between water and light is improved with respect to the photocatalyst, the photocatalytic function of titanium oxide can be further enhanced, and there is no outflow of titanium oxide, which facilitates replacement of the photocatalyst. Further, the present invention includes a photocatalyst body comprising titanium oxide, a fixed bed photocatalytic reactor in which the photocatalyst body is arranged, means for feeding water to the reactor, and means for irradiating the photocatalyst body with light containing ultraviolet rays. It is a water purifying apparatus that includes the above, and controls the flow of water in a cascade manner and also performs feedback control, and can accurately control the concentration of the object to be treated. Also,
The present invention provides water for purifying water in a fixed-bed photocatalytic reactor by feeding water to a fixed-bed photocatalytic reactor using titanium oxide as a photocatalyst and irradiating the titanium oxide with light containing ultraviolet rays. A method for purifying water, such as water for seawater or water of rivers, lakes, dams, rivers or domestic water, industrial water, agricultural water, or raw water used for these water, water for aquatic animals, and Is useful for easily and easily purifying various water such as domestic wastewater, industrial wastewater from manufacturing industry, agriculture, fisheries, wastewater from sewage treatment plants, agricultural polluted wastewater from golf courses, etc. That's the method.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of a purification device of the present invention in a first embodiment.

FIG. 2 is a conceptual diagram of a purifying device of the present invention in a third embodiment.

FIG. 3 is a conceptual diagram of a purification device of the present invention in a fourth embodiment.

[Explanation of Codes] A, B ... Photocatalyst 1, 5, 8 ... Fixed-bed photocatalytic reactor 2 ... White fluorescent lamp 3, 7, 10. Pumps 4, 11 --- Water tanks 6, 9, --- Black light → --- Direction of water flow

Front page continuation (72) Inventor Eiji Nomura 2-3-1, Nishi-Shibukawa, Kusatsu City, Shiga Ishihara Sangyo Co., Ltd. Central Research Laboratory (72) Inventor Tokuo Suita 2-3-1, Nishi-Shibukawa, Kusatsu City, Shiga Prefecture Ishihara (72) Inventor Akira Fujishima, 710 Nakamaruko, Nakahara-ku, Kawasaki City, Kanagawa Prefecture 5 (72) Kazuhito Hashimoto, Inori, Kosugaya-cho, 2000, Sakae-ku, Yokohama-shi, Kanagawa Prefecture 2 Minami-Kosugaya Houses 2 506

Claims (12)

[Claims] 1. A photocatalyst body comprising titanium oxide, a fixed-bed photocatalytic reactor in which the photocatalyst body is arranged, means for feeding water to the reactor, and means for irradiating the photocatalyst body with light containing ultraviolet rays. A water purifying apparatus comprising: a water flow cascade control. 2. The water purifying apparatus according to claim 1, further comprising means for feedback control. 3. The water purifying apparatus according to claim 1, wherein a photocatalyst having titanium oxide supported on the surface of the filler is arranged in a fixed bed photocatalytic reactor. 4. The water purifying apparatus according to claim 1, wherein a filler supporting titanium oxide as a photocatalyst is used as a photocatalyst, and the water flow is cascade-controlled. 5. The water purifying apparatus according to claim 1, wherein titanium oxide, which is a photocatalyst, is supported on a light-transmissive filler to form a photocatalyst, and the water flow is cascade-controlled. 6. The light containing ultraviolet light is at least one light selected from the group consisting of sunlight, fluorescent light, black light, germicidal lamp, mercury lamp, halogen lamp and incandescent lamp. Item 1. The water purification device according to item 1. 7. The water purifying apparatus according to claim 1, which purifies domestic water, industrial water, agricultural water, or raw water used therein. 8. The water purifying apparatus according to claim 1, which purifies water in a breeding area of aquatic organisms. 9. The water purification apparatus according to claim 1, which purifies domestic wastewater, industrial wastewater, or wastewater from a sewage treatment plant. 10. The photocatalyst-carrying filler is a light-transmitting material having a transmittance of 50% or more with respect to irradiation light, and a filler of two or more sizes is used in combination as a photocatalyst body. At the same time, the water purifying apparatus according to claim 1, wherein the thickness of the packed layer of the photocatalyst body is set to 50 mm or less in the entrance direction of the irradiating light. 11. A fixed bed photocatalytic reactor according to claim 1, wherein titanium oxide is used as a photocatalyst, and water is sent to the titanium oxide, and the titanium oxide is irradiated with light containing ultraviolet rays to control the water flow in cascade. A method for purifying water, comprising purifying water in the fixed bed photocatalytic reactor. 12. A fixed bed photocatalytic reactor according to claim 1, wherein titanium oxide is used as a photocatalyst, and water is fed to the titanium oxide, and the titanium oxide is irradiated with light containing ultraviolet rays to control the water flow in cascade. In addition, a method for purifying water, which comprises purifying water in the fixed bed photocatalytic reactor while performing feedback control.