JP4093409B2 - Fluid purification method and fluid purification device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
This invention sterilizes and purifies fluids such as bath water, domestic wastewater, drinking water, pool water, cooling water, washing water, stored water, aquaculture water, industrial waste water, agricultural water such as hydroponics, and air. The present invention relates to a fluid purification method and a fluid purification apparatus.
[0002]
[Prior art]
[Patent Document 1]
JP-A-8-89725 [Patent Document 2]
JP, 11-262759, A Conventionally, as a sterilization and purification device of water and air, there were an ultraviolet sterilizer, an ozone sterilizer, a photocatalyst sterilizer, etc. Among them, the ultraviolet sterilizer uses a lamp that generates light in the ultraviolet wavelength band. However, the electrodeless discharge lamp having a short lifetime and a long lifetime is expensive and requires a high maintenance cost. In addition, uniform light distribution cannot be performed around the entire circumference of the lamp, and a large processing apparatus requires a plurality of light sources, which requires equipment costs. Furthermore, the lamp surface or cover that comes into contact with the sewage to be treated is contaminated with organic matter or inorganic matter, so that periodic cleaning work is required.
[0003]
Since the ozone sterilization apparatus discharges oxygen by a general silent discharge method to ozonize oxygen, the contact between oxygen and the discharge site is short, and high concentration ozone cannot be generated. In addition, ozone could not be efficiently dissolved in water, and the generated ozone escaped into the atmosphere without returning to oxygen or dissolving in water. Furthermore, when ozone is made high, there is also a problem that there is an odor due to leaked ozone and it is harmful to the human body.
[0004]
In the photocatalyst sterilization apparatus, it is difficult to fix the titanium oxide as the photocatalyst, and the titanium oxide peels off due to long-term use, resulting in a decrease in performance. Furthermore, although oxygen is required for sterilization using a photocatalyst, sewage and bath water have little oxygen and cannot effectively exhibit the sterilization action of the photocatalyst. In addition, the photocatalyst needs light, and it is difficult to irradiate the entire photocatalyst with uniform light, and bacteria and organic substances come into contact with the photocatalyst to exert a bactericidal action, so a large surface area is necessary. It was difficult to increase the surface area of the photocatalyst.
[0005]
Furthermore, as disclosed in Patent Documents 1 and 2, a reaction vessel provided with a photocatalyst is provided in the middle of a path for circulating the water to be treated, and the reaction vessel is irradiated with ultraviolet rays to be treated with the photocatalyst. Some have been proposed to detoxify these bacteria. In this fluid purification device, a net sprayed with titanium oxide is placed in a reaction vessel, irradiated with an ultraviolet lamp, passed through water to be treated and sterilized by the action of a photocatalyst. Patent Document 2 also proposes a treatment method for supplying a gas containing ozone into the water to be treated using the same apparatus.
[0006]
The principle of sterilization treatment using this photocatalyst is as follows. When a photocatalyst such as titanium dioxide which is a semiconductor material is irradiated with ultraviolet light having a wavelength of 400 nm or less, holes are generated in the valence band and electrons are generated in the conduction band. The oxidation potential of the holes is higher than that of fluorine, ozone, hydrogen peroxide, etc., and the organic matter is completely oxidized and decomposed by the photocatalyst, and finally it is completely oxidized to carbon dioxide gas, water, sulfuric acid, nitric acid, etc. Is done. The mechanism of the oxidation reaction by the photocatalyst is that the oxidation reaction occurs due to the hydroxyl radical (OH radical) that is rich in the reaction activity that is generated by the reaction of holes or water generated when ultraviolet light is irradiated to the photocatalyst. It is believed that. At this time, the reduction reaction between the electrons generated simultaneously with the holes generated when the ultraviolet rays are irradiated and oxygen gas or the like proceeds in parallel. The action of the photocatalyst has a stronger sterilizing ability than conventional sterilizing agents such as ozone, hydrogen peroxide, chlorine, and the like, and has a function of decomposing organic substances. In addition, the lifetime of holes and OH radicals generated by light irradiation is as short as less than milliseconds, so there is no residue after treatment like oxidants such as ozone and hydrogen peroxide, and no equipment for treating residual oxidants is required. There is an advantage of being. For this reason, many fluid purification devices using a photocatalyst have been proposed so far.
[0007]
However, since the action of the photocatalyst occurs only on the surface of the photocatalyst irradiated with light, it is necessary to increase the surface area of the photocatalyst to increase the contact efficiency with the water to be treated in order to perform the treatment efficiently. In addition, since holes or OH radicals generated when the photocatalyst is irradiated with ultraviolet light have a short lifetime, it is necessary to react in a short time. Further, there is a problem that ultraviolet light is easily absorbed by water and easily attenuates in water.
[0008]
Furthermore, in the case of the above-mentioned conventional technology, the oxidation and sterilization action occurs only on the surface of the photocatalyst irradiated with ultraviolet rays, and only a part of the water to be treated that contacts the surface of the net sprayed with the photocatalyst such as titanium oxide. Only the processing was performed, and the processing capability was low. In addition, a net on which a photocatalyst such as titanium oxide is sprayed easily peels off the photocatalyst on the surface and has low durability. When the thermally sprayed photocatalyst disappears, there is a problem that the function as a photocatalyst is lost and the portion needs to be replaced.
[0009]
[Problems to be solved by the invention]
The present invention has been made in view of the above-described problems of the prior art. A fluid purification method and fluid purification in which a fluid to be treated is uniformly and effectively sterilized and purified, and has a simple configuration and is easy to maintain. An object is to provide an apparatus.
[0010]
[Means for Solving the Problems]
The present invention provides a reaction vessel provided with an outer cylinder in the middle of a pipe through which a fluid to be treated such as sewage, bathtub water, tap water or air flows, and one provided on the entire inner circumference of the outer cylinder of the reaction vessel. A transparent inner cylinder provided with a predetermined space in the outer cylinder of the reaction vessel and having an inlet and an outlet communicating with the pipe, respectively, and a pair of the electrode and the one electrode provided in the inner cylinder. And supplying oxygen to a sealed space between the outer cylinder and the inner cylinder, generating a discharge between the electrodes between the outer cylinder and the inner cylinder, and Is a fluid purification method in which ozone is generated by passing through the discharge section between the electrodes, and this ozone is mixed with the fluid flowing into the inner cylinder.
[0011]
Further, a photocatalyst is provided in the inner cylinder, ultraviolet rays are generated by the discharge , and the photocatalyst in the transparent inner cylinder is caused to function by the ultraviolet rays. In addition, a titanium or titanium alloy large surface area material is provided in the inner cylinder, a titanium dioxide photocatalyst is formed on the surface of the large surface area material by the oxidizing action of ozone, and ultraviolet rays are generated by the discharge. The photocatalyst of the large surface area material in the transparent inner cylinder is caused to function by ultraviolet rays.
[0012]
Further the invention, sewage and bath water, a reaction vessel equipped with an outer cylinder provided in the middle of the pipe in which the processing fluid flows, such as tap water or air, is provided on the entire circumference the outer tube inner surface of the reaction vessel One electrode, a transparent inner cylinder provided with a predetermined space in the outer cylinder of the reaction vessel and having an inlet and an outlet each communicating with the pipe, and the one electrode provided in the inner cylinder From the other electrode forming a pair, an oxygen supply means for supplying oxygen to a sealed space between the outer cylinder and the inner cylinder of the reaction vessel, and the oxygen that has passed between the outer cylinder and the inner cylinder, The fluid purification device includes a mixing device that mixes ozone generated by the discharge between the electrodes with the fluid on the upstream side of the inner cylinder.
[0013]
The reaction vessel is formed of a stainless steel cylinder, and this cylinder also serves as an outer cylinder to constitute the one electrode. The inner cylinder has a large surface area material made of titanium or a titanium alloy, and the large surface area material is a photocatalyst and constitutes the other electrode. The photocatalyst may be a glass bead surface provided with a photocatalyst, or a photocatalyst such as titanium oxide provided on the surface of a large surface area material such as stainless steel, ceramics, or glass fiber.
[0014]
This invention generates discharge between the inner cylinders of the reaction vessel of the fluid to be treated, generates ozone by passing oxygen between them, and mixes this ozone in the water to be treated for sterilization and purification treatment It is. Furthermore, the ultraviolet light generated by the discharge is applied to the photocatalyst of the large surface area material in the inner cylinder to cause sterilization and purification action by the photocatalyst, and further, the light catalyst is applied to the surface of the large surface area material containing titanium by the above ozone or the like. It is designed to be played back at all times.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic view showing an embodiment of a fluid purification apparatus of the present invention. A fluid purification apparatus 10 according to this embodiment is a bath that circulates in a hot spring, a health facility, or the like as treated water 12 that is a treated fluid. Of hot water. The fluid purification device 10 of this embodiment includes a hair catcher 18 that collects hair in a circulation pipe 16 through which the water 12 to be treated in the bathtub 14 flows and circulates, and a circulation pump 20 that is provided downstream of the hair catcher 18. have. A filtration tank 22 is provided on the downstream side of the circulation pump 20, and a heat exchanger 24 is provided on the downstream side of the filtration tank 22, and the temperature of the water to be treated 12 is raised to a predetermined temperature, and is passed through the circulation pipe 16. The treated water 12 is returned to the large bathtub 14.
[0016]
As shown in FIGS. 1 and 2, the circulation pipe 16 between the hair catcher 18 and the circulation pump 20 has a mesh or a titanium wire, a collection of fibrous titanium materials, In addition, a reaction vessel 32 containing a large surface area material 30 such as a porous titanium material is attached. The large surface area material 30 may be preliminarily formed with a titanium dioxide photocatalyst on the surface of titanium or a titanium alloy, or may be one that forms a titanium dioxide photocatalyst during use with ozone, as will be described later. Further, a photocatalyst may be attached to a large surface area material other than titanium such as glass or stainless steel.
[0017]
The reaction vessel 32 is a stainless steel cylinder, and circulation pipes 16 are connected to both ends thereof. A concentrically transparent inner cylinder 34 is attached in the reaction vessel 32 which is an outer cylinder, and the inner cylinder 34 communicates with an inlet 34a and an outlet 34b of a connection portion with the circulation pipe 16 in an airtight state. Yes. Therefore, the space between the inner wall of the reaction vessel 32 and the outer wall of the inner cylinder 34 is a cylindrical sealed space 32a. Between the inner wall of the reaction vessel 32 and the outer wall of the inner cylinder 34, a pipe 36 for supplying air containing oxygen to the downstream end thereof is connected to a cylindrical sealed space 32a. An air pump 38 is provided so that air can be supplied through a filter 40 that removes dust and moisture.
[0018]
A pipe 42 communicating with the space 32a is connected to the upstream side of the space 32a between the reaction vessel 32 and the inner cylinder 34, and the pipe 42 is connected to a mixing device 44 attached to the circulation pipe 16 on the upstream side. Has been. As shown in FIG. 3, the mixing device 44 is a porous body such as a ring-shaped ceramics or metal having a pipe 42 connected to the side surface, or an open cell resin, and discharges the gas as fine bubbles.
[0019]
The inner cylinder 34 is made of quartz glass or borosilicate glass that allows easy passage of ultraviolet rays. Since the stainless steel reaction vessel 32 is connected to the positive side of the power supply device as one electrode for discharge described later, the stainless steel portion is installed in an insulated state. The large surface area material 30 such as a titanium wire constitutes the other electrode together with the water to be treated 12 in the inner cylinder 34 and is connected to the ground side of the power supply device.
[0020]
Next, the operation and action of this embodiment will be described. The water to be treated 12 is pressurized by the circulation pump 20 and is pumped into the filtration tank 22 of the fluid purification device 10 to remove foreign matter and the like to some extent, and is heated to a certain temperature via the heat exchanger 24 and is sent to the large bathtub. 14 is returned. Further, on the upstream side of the circulation pump 20, the water 12 to be treated from the large bathtub 14 is removed by the hair catcher 18 by the circulation pipe 16 and is sucked into the circulation pump 20 through the reaction container 32.
[0021]
In the reaction vessel 32, silent discharge is generated in the space 32a by the electrode by the reaction vessel 32 and the other electrode by the large surface area material 30 and the water to be treated 12 in contact therewith. The voltage at this time is adjusted as appropriate, and a power supply device (not shown) is set to a voltage that allows good silent discharge. Furthermore, ultraviolet rays are generated by silent discharge all around the space 32a. The generated ultraviolet rays are reflected from the inner surface of the stainless steel reaction vessel 32, are irradiated into the transparent inner cylinder 34, and are irradiated onto the surface of the large surface area material 30 on which the photocatalyst is formed. Furthermore, air containing oxygen is sent from the air pump 38 through the pipe 36 into the space 32a, and the oxygen is converted into ozone by passing through the discharge section in the space 32a and sent out from the pipe 42. . This ozone is mixed into the treated water 12 flowing through the circulation pipe 16 by being made into fine bubbles by the mixing device 44, and flows into the upstream side of the inner cylinder 34.
[0022]
The ozone mixed with the water to be treated 12 passes through the gap between the large surface area materials 30 in the reaction vessel 32. The photocatalyst on the surface of the large surface area material 30 generates OH radicals by irradiation with ultraviolet rays by silent discharge, thereby sterilizing and decomposing organic substances. This sterilization / purification mechanism is as described above. At the same time, sterilization with ozone mixed on the upstream side is also performed. Further, the large surface area material 30 made of titanium or a titanium alloy oxidizes the exposed titanium atoms with ozone in the liquid to be treated 12 even when the photocatalyst on the surface is peeled off, and the surface of the titanium dioxide is easily formed on the surface. A photocatalyst is formed.
[0023]
According to the fluid purification method and apparatus of this embodiment, it is not necessary to use an ultraviolet lamp, and it is possible to always irradiate the inner cylinder 34 with uniform ultraviolet rays. In addition, in the inner cylinder 34, organic substances do not adhere to the inner surface due to the action of the photocatalyst, so that a clean surface can be maintained at all times, and the number of cleaning steps can be greatly reduced. Further, since silent discharge occurs around the entire circumference of the reaction vessel 32 and ultraviolet rays are incident from the whole circumference of the inner cylinder 34, the ultraviolet rays are efficiently irradiated onto the photocatalyst of the large surface area material 30.
[0024]
Moreover, in the space 32a in the reaction vessel 32, discharge occurs over a relatively long section, oxygen can be efficiently converted into ozone, and high concentration ozone can be generated. And the to-be-processed water 12 sterilization and the decomposition | disassembly process of organic substance can be reliably performed with high efficiency with an ultraviolet-ray, ozone, and a photocatalyst. For example, it is possible to reliably prevent contamination of bath water by Legionella bacteria and the like, and a large amount of water to be treated 12 can be treated. Furthermore, even if the photocatalyst by titanium dioxide of the large surface area material 30 in the reaction vessel 32 is peeled off due to long-term use, the ozone from the ozone generator 26 causes the surface of the large surface area material 30 made of titanium or a titanium alloy. In this case, titanium dioxide is always produced and the photocatalyst is not peeled off.
[0025]
Further, in the photocatalyst upon irradiation with ultraviolet light, electrons generated simultaneously with holes react rapidly with oxygen to generate superoxide (O ₂ ⁻ ). At this time, if oxygen is insufficient, unreacted electrons recombine with holes and inhibit the oxidation reaction of holes. In this invention, sufficient oxygen-containing gas including ozone is supplied to the photocatalyst surface. Therefore, recombination of the electrons and holes can be prevented, and as a result, the oxidation reaction efficiency between the water to be treated 12 and the titanium dioxide photocatalyst can be increased.
[0026]
Furthermore, according to this embodiment, due to the mixing and stirring effect of the water to be treated 12 in the reaction vessel 32, the water to be treated 12 can be efficiently brought into contact with the surface of the photocatalyst, and sufficient oxygen is supplied. The reaction efficiency between the photocatalyst and the water to be treated 12 can be dramatically increased.
[0027]
The fluid purification device of the present invention is not limited to the above embodiment, and as shown in FIG. 5, a plurality of electrodes 50 are provided in the longitudinal direction on the inner peripheral surface of the inner cylinder 34 in the reaction vessel 32, and are made of stainless steel. A silent discharge may be generated in the space 32 a between the reaction vessel 32 and the electrode 50. Thereby, even when the conductivity of the fluid flowing in the inner cylinder 34 is low, silent discharge can be generated in the space 32a. For example, drinking water or the like has low conductivity because there is little electrolyte in the liquid, but this can generate silent discharge well, efficiently generate ozone, and dissolve in drinking water flowing in the inner cylinder 34. I can do it. It is also sterilized by ultraviolet rays caused by silent discharge. When flowing drinking water, in order to prevent consumption of ozone by the photocatalyst, the photocatalyst is not put in the inner cylinder 34 and is used in the mode shown in FIG.
[0028]
Further, air may be passed through the inner cylinder 34 of the reaction vessel 32 shown in FIG. 4 to be used for air sterilization and deodorization. In this case, the air flowing in the inner cylinder 34 is sterilized by ozone and ultraviolet rays, and further, sterilization, decomposition of organic substances, deodorization, and the like are performed by a photocatalyst. In addition, ozone is consumed by the photocatalyst and is converted to oxygen so that the ozone odor does not leak.
[0029]
In addition, as shown in FIG. 6, the fluid purification apparatus of the present invention may mix ozone gas from the space 32 a in the reaction vessel 32 into the water to be treated 12 in the pipe 16 through the pressurizing pump 52. . In this case, air containing ozone is sucked using the negative pressure of the pipe flowing into the pressurizing pump 52, and is stirred into fine bubbles by the impeller of the pressurizing pump 52, so that more ozone gas is dissolved in the water 12 to be treated. To do. By using the pressurizing pump 52, even when the internal pressure of the water to be treated in the pipe 16 is high, ozone can be reliably and efficiently mixed and dissolved in the water to be treated 12. In addition, the fine bubbles of ozone and oxygen mixed in the water to be treated 12 further activate the photocatalyst.
[0030]
Further, the reaction vessel 32 is also used as a treatment tank such as the hair catcher 18, and a hair catcher basket is provided on the inlet side of the water to be treated 12 of the reaction vessel 32. The cylinder 34 may be provided and the large surface area material 30 may be provided therein. In this case as well, a silent discharge is generated between the inner cylinder 34 and the inner wall of the reaction vessel 32 to irradiate the inner cylinder with ultraviolet rays, and the generated ozone is exposed to the upstream side of the reaction vessel 32. Mix in treated water 12. Thereby, further downsizing and space saving of the apparatus can be achieved.
[0031]
Further, a fluorescent agent for effectively generating ultraviolet rays may be applied to the outer surface of the inner cylinder 34.
[0032]
Water to be treated which is the target of the fluid purification method and apparatus of the present invention includes domestic wastewater, industrial water, agricultural water such as hydroponics, water that requires sterilization, air, etc. It can be used for all fluids such as gas.
[0033]
【The invention's effect】
According to the fluid purification method and apparatus using a photocatalyst according to the present invention, ultraviolet rays can be generated effectively without using an ultraviolet lamp, and the water to be treated can be reliably sterilized and purified together with ultraviolet rays and ozone. it can. In addition, the generated ultraviolet rays are irradiated from the entire circumference of the inner cylinder to the inside, and even when a photocatalyst is used, the large surface area material that is the photocatalyst is efficiently irradiated with ultraviolet rays, and the sterilization by the photocatalyst and the decomposition of organic matter are performed efficiently Can be made. By combining the treatment with the photocatalyst, harmful organic substances, microorganisms such as bacteria, odorous substances and hardly decomposable substances contained in the water to be treated can be efficiently sterilized and decomposed and removed in large quantities.
[0034]
In addition, by forming a large surface area material with a photocatalyst on its surface using titanium or a titanium alloy, even if the photocatalyst of titanium dioxide is peeled off after long-term use, the titanium atoms of the large surface area material can be obtained by a strong oxidizing action by ozone. Oxidize and constantly regenerate the titanium dioxide photocatalyst on the surface. Thereby, the large surface area material can function semipermanently as a photocatalyst, and can solve problems such as peeling of the photocatalyst due to use.
[Brief description of the drawings]
FIG. 1 is a schematic piping diagram of a fluid purification device according to an embodiment of the present invention.
FIG. 2 is a longitudinal sectional view of a reaction vessel according to this embodiment.
FIG. 3 is a front view of the mixing apparatus of this embodiment.
FIG. 4 is a cross-sectional view of the reaction vessel of this embodiment.
FIG. 5 is a cross-sectional view showing another embodiment of the reaction vessel of the present invention.
FIG. 6 is a longitudinal sectional view showing still another embodiment of the reaction vessel of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Fluid purification device 12 Water to be treated 14 Large bathtub 16 Circulation piping 20 Circulation pump 22 Filtration tank 24 Heat exchanger 30 Large surface area material 32 Reaction vessel 34 Inner cylinder 38 Air pump 44 Mixing device

Claims (4)

A reaction vessel provided in the middle of a pipe through which the fluid to be treated is provided and provided with an outer cylinder , one electrode provided on the entire inner surface of the outer cylinder of the reaction vessel, and a predetermined inside of the outer cylinder of the reaction vessel A transparent inner cylinder provided with a space and having an inlet and an outlet each communicating with the pipe, the other electrode provided in the inner cylinder and paired with the one electrode, and provided in the inner cylinder Provided with a photocatalyst , supplying oxygen into a sealed space between the outer cylinder and the inner cylinder, generating a discharge between the electrodes between the outer cylinder and the inner cylinder, Ozone is generated by passing through the discharge section between the electrodes, and this ozone is mixed with the fluid flowing into the inner cylinder, and ultraviolet light is generated by the discharge, and the photocatalyst in the transparent inner cylinder is generated by the ultraviolet light. A fluid purification method characterized by causing the function to function . A reaction vessel provided in the middle of a pipe through which the fluid to be treated is provided and provided with an outer cylinder, one electrode provided on the entire inner surface of the outer cylinder of the reaction vessel, and a predetermined inside of the outer cylinder of the reaction vessel A transparent inner cylinder provided with a space and an inlet and an outlet each communicating with the pipe, the other electrode provided in the inner cylinder and paired with the one electrode, and positioned in the inner cylinder A large surface area material made of titanium or titanium alloy is provided, oxygen is supplied to a sealed space between the outer cylinder and the inner cylinder, and a discharge is generated between the electrodes between the outer cylinder and the inner cylinder. The oxygen passes through the discharge section between the electrodes to generate ozone, and this ozone is mixed with the fluid flowing into the inner cylinder, and the surface of the large surface area material is oxidized by the ozone to produce titanium dioxide. The photocatalyst is formed and purple is generated by the above discharge. Line to generate a fluid purification method, characterized in that to function photocatalyst of the large surface area materials in the inner cylinder the clear by ultraviolet. A reaction vessel provided in the middle of a pipe through which the fluid to be treated is provided and provided with an outer cylinder , one electrode provided on the entire inner surface of the outer cylinder of the reaction vessel, and a predetermined inside of the outer cylinder of the reaction vessel A transparent inner cylinder provided with a space and an inlet and an outlet communicating with the pipe respectively, and a large surface area material made of titanium or titanium alloy provided in the inner cylinder and paired with the one electrode From the other electrode, the oxygen supply means for supplying oxygen to the sealed space between the outer cylinder and the inner cylinder of the reaction vessel, and the oxygen passing between the outer cylinder and the inner cylinder, A fluid purification device comprising: a mixing device that mixes ozone generated by electric discharge with a fluid upstream of the inner cylinder.     4. The fluid purification apparatus according to claim 3, wherein the reaction vessel is formed of a stainless steel cylinder, and the cylinder also serves as an outer cylinder to constitute the one electrode.

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