JP2000354642A - Method and device for decomposing dioxins - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily decompose dioxins at normal pressure and room temperature by bringing functional water produced by electrolysis of water containing electrolyte into contact with a medium containing dioxins under exposure to the light. SOLUTION: Water, in which electrolyte is dissolved, is fed to a water bath 101 through a pipe 11 and electric power is supplied from a power source 109 to electrodes 103, 105 for electrolysis to generate acidic water on the anode side 105, whereupon dioxins in the form of liquid and liquid medium containing dioxins are continuously supplied to the anode side 105 from a pipe 115 of the water bath 101, while the interior of the bath 101 is illuminated with the light by means of a light source 166 set in the bath 101. As a result, the dioxins are brought into contact with functional water and decomposed and moreover the decomposition is accelerated under exposure to the light. Thereafter, the acidic water which is deactivated by the reaction with the dioxins is discharged from the bath 101 to a tank 119 through a discharge pipe 118.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for decomposing dioxins and an apparatus for decomposing dioxins used therein.

[0002]

2. Description of the Related Art Dioxin, which is said to be generated by incineration of garbage and the like, is extremely toxic to the human body even in a small amount and is a substance showing particularly strong carcinogenicity, and has recently become a major social problem. Therefore, establishment of a processing method is strongly desired. Generally, dioxins refer to polychlorinated dibenzoparadioxin (PCDD) and polychlorinated dibenzofuran (PCDF), and there are many compounds depending on the number and position of chlorine bonds. These compounds are mo
The number of chlorine bonds is represented by an initial letter of a prefix representing a number such as no-, di-, and tri- and a numerical value.
D, D2CDD, T3CDD... Can be displayed.

[0003] Conventionally reported dioxin treatment methods include, for example, a decomposition method using a microorganism, a method using a chemical reaction, and a treatment using combustion. As a decomposition method using a microorganism, for example, Psudomonas aeru
ginosa or P. ginosa, a microorganism having lignin degradability. chrysosporium, dioxins,
In particular, there has been proposed a method of decomposing by adding to a liquid containing polychlorinated dibenzoparadioxin (PCDDs) and / or polychlorinated dibenzofuran (PCDFs) substituted with more than 4 chlorines (JP-A-10-323646). Reference).

[0004] In addition, as for the chemical reaction, an object to be treated containing dioxins is heated in an aqueous alkali solution to which an alkali silicate is added as a reaction accelerator to remove dioxins contained in the object to be treated. Hydrolysis (Japanese Patent Application Laid-Open No. 8-98900), or the treatment of a dioxin-containing substance with a gaseous amine compound at 100 ° C.
A method of contacting under conditions of not less than 300 ° C.
0-272440).

Although there are many unknowns in the process of dioxin generation, 250 to 5 parts of hydrogen chloride derived from plastics generated during incineration of garbage and hydrocarbons in the unburned combustion components are present.
It is said to react and form in the range of 00 ° C. For this reason, in order to suppress the generation of dioxin, many measures have been taken to increase the combustion efficiency in a garbage incinerator so as not to generate unburned components (Japanese Patent Laid-Open Nos. 10-196930 and 7-196). JP-A-138054, JP-A-10-13
No. 2254). Recently, a method using supercritical water (JP-A-9-327678) and a method of decomposing with ozone, hydrogen peroxide and hydroxy radicals generated by ultraviolet rays (JP-A-11-033570) have been proposed. Is being developed.

[0006]

As described above, various methods for decomposing dioxins have been proposed. However, according to the study of the present inventors, all of them require a complicated apparatus for decomposition. Is necessary in many cases, or further detoxification treatment of decomposition products is required, and it is concluded that there is a need for less troublesome and environmentally friendly technology for decomposition of dioxins. Reached. The present invention has been made based on new findings by the present inventors, and an object of the present invention is to realize a simpler method for decomposing dioxins, which can be performed at normal pressure and normal temperature, and a method for realizing the method. An object of the present invention is to provide a device for decomposing dioxins to be obtained.

[0007]

The above objects are achieved by the present invention described below. That is, the present invention provides a method for decomposing dioxins, which comprises a step of bringing functional water generated by electrolysis of water containing an electrolyte into contact with a medium containing dioxins under light irradiation, and used in the method. It is a device for decomposing dioxins.

[0008] The inventors of the present invention have studied for the purpose of achieving the above-mentioned problems, and found that a bactericidal effect (Japanese Unexamined Patent Application Publication No.
Using functional water obtained by electrolysis of water, which is reported to have a cleaning effect of contaminants on a semiconductor wafer (JP-A-7-51675), for example, acidic water; In addition, the present inventors have found out that dioxins are decomposed by light irradiation, leading to the present invention. That is, the method for decomposing dioxins according to one embodiment of the present invention includes a step of bringing functional water generated by electrolysis of water containing an electrolyte into contact with a medium containing dioxins under light irradiation. And The reason why the decomposition of various dioxins is promoted by the irradiation of functional water and light as described above is not clear. But,
For example, water generated by electrolysis of water containing an electrolyte such as sodium chloride contains hypochlorous acid or hypochlorite ion, and this hypochlorous acid or hypochlorite ion is converted to chlorine by the action of light. It is considered that a radical, a hydroxyl radical or a superoxide is induced to accelerate the above decomposition reaction.

A method for decomposing dioxins according to another embodiment of the present invention comprises a step of bringing water containing hypochlorous acid into contact with a medium containing dioxins under light irradiation. I do. A device for decomposing dioxins according to another embodiment of the present invention includes a container having a pair of electrodes and a power supply for applying a potential to the electrodes, a unit for supplying water in which an electrolyte is dissolved in the container, and irradiation with light. And a means for supplying a medium containing dioxins. Further, a dioxin decomposing apparatus according to another embodiment of the present invention includes a decomposition tank, means for supplying functional water generated by electrolysis of water to the decomposition tank, and a dioxin to be decomposed. It is characterized by having means for supplying to the decomposition treatment tank and means for irradiating light to the decomposition treatment tank.

Japanese Patent Application Laid-Open No. 8-281271 discloses that
There is disclosed a technique for decomposing a dye in dyeing wastewater in an electrolytic cell by hypochlorous acid and / or hypochlorite ions generated by electrolysis. Also, the magazine "Water Treatment Technology" V
ol. 37, no. 5 (1996), page 33, describes the treatment of dyeing wastewater using an electrochemical reaction. In the indirect electrolysis method as a method for decomposing coloring component molecules of a dye by electrolysis, first, an oxidizing agent is electrolyzed by electrolysis. And indirectly decompose the dye by its oxidizing power. Further, most of hypochlorous acid is used as the oxidizing agent, and sodium chloride is contained in the wastewater. It is described that chlorine gas generated at the anode when electrolysis is performed by adding OH is generated by reaction with hydroxyl ions generated at the cathode. But,
There is no description in these patent publications and magazines suggesting that dioxins can be decomposed by these methods. Furthermore, there is no description of irradiating light to promote decomposition.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail by way of preferred embodiments of the present invention. One embodiment of the method for decomposing dioxins of the present invention is characterized in that the method comprises a step of contacting functional water produced by electrolysis of water with dioxins to be decomposed under light irradiation. In one embodiment, the method includes a step of bringing an aqueous solution containing hypochlorous acid into contact with a medium containing dioxins under light irradiation. Hereinafter, each constituent material used in the method for decomposing dioxins of the present invention having these embodiments will be described.

[Functional Water] (Acid Water) As the functional water generated by electrolysis of water that can be used in the present invention, for example, an electrolyte (eg, sodium chloride or potassium chloride) is dissolved in raw water, This water can be obtained in the vicinity of the anode by performing electrolysis in a water tank having a pair of electrodes. In the present invention, among the functional water thus obtained, the oxidation-reduction when the hydrogen ion concentration (pH value) is 1 or more and 4 or less, the working electrode is a platinum electrode, and the reference electrode is silver-silver chloride is measured. The potential is 800 mV or more and 1500 mV or less, and the chlorine concentration is 5 mg / l.
It is preferable to use one having a property of 150 mg / l or less.

In order to produce functional water having the above-mentioned characteristics, the concentration of the electrolyte in the raw water before the electrolysis is adjusted to, for example, 20% when sodium chloride is used as the electrolyte.
mg / l to 2000 mg / l, and the electrolytic current value at that time is desirably 2A to 20A. As a means for obtaining such functional water, a commercially available strongly acidic electrolyzed water generator, for example, trade name: Oasis Bio Half (manufactured by Asahi Glass Engineering Co., Ltd.), trade name: strong electrolyzed water generator Model FW-2
00 (manufactured by Amano Corporation) or the like can be used.
Also, if a diaphragm is arranged between a pair of electrodes when performing electrolysis,
Mixing of acidic water generated in the vicinity of the anode and alkaline water generated in the vicinity of the cathode can be prevented, and acidic water capable of decomposing dioxins more efficiently can be obtained. As the diaphragm used at this time, for example, an ion exchange membrane or the like is suitably used.

(Mixed water) Functional water generated by electrolysis of water that can be used in the present invention includes:
For example, functional water having no diaphragm between the above-mentioned pair of electrodes or generated near the anode of an electrolysis apparatus except for the above, for example, having an oxidation-reduction potential of 300 mV or more and 1100 mV or less, and chlorine Functional water having a concentration of 2 mg / l or more and 100 mg / l or less and a pH of 4 to 10 is also included. Functional water having such properties can also be used effectively for decomposing organic compounds. Such functional water is also obtained as neutral functional water. Furthermore, acidic water and alkaline water prepared by disposing a diaphragm between electrodes can be mixed to obtain functional water having resolution, and such functional water can also be used effectively.
At this time, the mixing ratio of the acidic water and the alkaline water is a volume ratio,
For example, it is desirable to use 1: 0 to 1: 1.

(Synthetic functional water) Functional water having a dioxin resolution substantially equivalent to that of the functional water generated by the above-mentioned electrolysis is obtained not only by electrolysis but also by dissolving various reagents in raw water to obtain synthetic functional water. It is also possible to prepare. For example, it can be obtained by using 0.001 N to 0.1 N hydrochloric acid, 0.005 N to 0.02 N sodium chloride, and 0.0001 M to 0.01 M sodium hypochlorite. Functional water having a pH of 4 or more can be prepared not only by electrolysis but also by dissolving various reagents in raw water. For example, hydrochloric acid 0.001N
~ 0.1N, sodium hydroxide 0.001N ~ 0.1
N and sodium hypochlorite 0.0001M to 0.1M.
01M, and only hypochlorite, for example, sodium hypochlorite 0.0001
It can also be obtained by setting M to 0.01M. A mixture of hydrochloric acid and hypochlorite with a pH of 4.0 or less and a chlorine concentration of 2 m
g / l or more of functional water can also be prepared.

In place of the hydrochloric acid used above, other inorganic or organic acids can be used. At this time, for example, hydrofluoric acid, sulfuric acid, phosphoric acid and boric acid can be used as the inorganic acid, and acetic acid, formic acid, malic acid, citric acid, oxalic acid and the like can be used as the organic acid. Also, a weakly acidic water powder generating agent, for example, N ₃ C ₃ which is commercially available as trade name: Kinosan 21X (manufactured by Clean Chemical Co., Ltd.)
Even if O ₃ NaCl ₂ or the like is used, functional water usable in the present invention can be produced. As is clear from the examples described below, the synthetic functional water obtained by the preparation of these chemicals has a difference in the decomposing ability, but by irradiating light, the functional water obtained by the electrolysis described above is sufficiently sufficient. It has the ability to decompose dioxins.

[Dioxins to be Decomposed] Examples of dioxins to be decomposed in the method for decomposing dioxins of the present invention include polychlorinated dibenzoparadioxin (PCDD) and polychlorinated dibenzofuran (PCDF). Can be The form of the medium containing these dioxins may be either gaseous or liquid. Examples of the liquid include raw water such as tap water, river water, and seawater. The pH of these raw waters is usually between 6 and 8 and the chlorine concentration is at most less than 1 mg / liter, and such raw waters naturally have the resolution of dioxins as described above. Not.

[Light Source for Light Irradiation in Decomposition] The method for decomposing dioxins of the present invention is characterized in that light is irradiated when decomposing dioxins with functional water as described above. According to the study of the present inventors, the light to be irradiated is, for example, at a wavelength of 300 to 500 nm, particularly at 350 to 500 nm.
Light of ~ 450 nm has been found to be particularly preferred for use in decomposing dioxins. Further, the light irradiation intensity for a mixture of functional water or an aqueous solution of hypochlorous acid and a dioxin to be decomposed is 10 μm from the viewpoint of decomposition efficiency.
W / cm ^{2 to} 10 mW / cm ² , especially 50 μW / cm
It is ^{2 ~5mW} / cm ² was found to be preferable. Specifically, for example, in a light source having a peak at a wavelength of 365 nm, several hundred μW / cm ² (300 nm to 400 n
(measured between m), it was found that decomposition proceeded sufficiently for practical use.

As a light source of such light, for example, natural light such as sunlight and artificial light such as mercury lamp, black light and color fluorescent lamp can be suitably used. Irradiation of light to a mixture of functional water or an aqueous solution of hypochlorous acid and dioxins may be performed directly on the functional water, or via a transparent container made of glass, plastic, or the like. You may do it. Light irradiation may be performed in the process of generating functional water in the presence of dioxins, or dioxins may be added to functional water after generating functional water, and then irradiated with light. In any case, in order to remarkably promote the decomposition of dioxins, it is desirable to perform light irradiation at the time of contact between the functional water and the dioxins. In the above-described embodiment using the functional water or the aqueous solution of hypochlorous acid, it is not necessary to use 250 nm ultraviolet light which has a large influence on the human body as light for light irradiation for accelerating the decomposition.

According to the study of the present inventors, it has been found that in the case where dioxins are decomposed using the above-described various functional waters, in all cases, the decomposition proceeds by light irradiation. . This is because, as described above, for example, functional water generated by electrolysis of water containing an electrolyte such as sodium chloride contains hypochlorous acid or hypochlorite ions. Alternatively, it is considered that hypochlorite ion induces chlorine radicals, hydroxyl radicals, and superoxide by the action of light to promote the decomposition reaction of dioxins. The amount of hypochlorous acid in the functional water, which is considered to contribute to the decomposition of dioxins by the functional water generated near the anode by the electrolysis, can be obtained from the pH and the chlorine concentration of the functional water. Furthermore, functional water produced by electrolysis, for example, diluted with pure water or the like can be used for the decomposition of dioxins. FIG. 1 shows a process for decomposing dioxins by the above method and a process for measuring the abundance of dioxins after decomposition.

The apparatus for decomposing dioxins of the present invention, which is applicable to the method for decomposing dioxins using functional water as described above, will be described below. In such a decomposition apparatus, contact between functional water and dioxins under light irradiation may be performed at room temperature and normal pressure, and no special equipment or environment is required. For example, it is only necessary to introduce a dioxin or a medium containing dioxins into a container storing functional water and irradiate the light, or a medium containing dioxins or dioxins in a water tank having the prepared functional water. It only needs to be introduced under light irradiation. Examples of the configuration of the dioxin decomposition device include the following configurations (1) and (2).

(1) A method in which dioxins to be decomposed are directly charged into an electrolyzed water generating apparatus from which functional water is obtained, whereby the generated functional water is brought into contact with dioxins, and light is irradiated to the dioxins. FIG. 2 is a schematic view of a dioxin decomposing apparatus according to an embodiment of the present invention. Hereinafter, this will be described. In FIG. 2, reference numeral 101 denotes a water tank. The water tank includes a cathode 103 and an anode 105, a diaphragm 107 composed of an ion exchange membrane and the like disposed between these electrodes, a power supply 109 connected to these electrodes, and a pipe 111 for supplying water containing an electrolyte into the water tank. and pump 113, the dioxins or medium containing it to be degraded aquarium 1
01 is provided with a pipe 115 and a pump 117. Reference numeral 119 denotes a tank for storing functional water that has lost its activity as a result of reacting with dioxins in the water tank 101 .

[0023] In the device for decomposing dioxins having the above structure, the water tank 101, water containing dissolved electrolyte when supplied thereto through a pipe 111, filled with water aquarium 101 is dissolved an electrolyte. When power is supplied from the power supply 109 to the electrodes 103 and 105 for electrolysis, acidic water is generated on the anode 105 side. Therefore, liquid dioxins and a liquid medium containing dioxins are continuously supplied to the anode 105 side of the water tank 101 from the pipe 115 at a desired flow rate. Further, the same time, the light source 166 installed in 101 water tank, applying light to 101 water tank. As a result, the dioxins are decomposed in contact with the functional water in the water tank 101 , and the decomposition is promoted by light irradiation. Thereafter, the functional water deactivated by the reaction with the dioxins is transferred to the water tank 101 through the drain pipe 118.
From the tank 119. When the gas is discharged at this time, the gas is discharged from the discharge pipe 121. However, when gas is not discharged, the discharge pipe 121 is not necessarily required. The electrolyte may be dissolved in the water discharged to the tank 119 and supplied to the water tank 101 again.

In the apparatus for decomposing dioxins having the structure shown in FIG.
The electrolyte solutions on the 03 side and the anode 105 side are not moved to the opposite sides, respectively, and cations (eg, Na ⁺ , Ca ⁺ , Mg ²⁺ , K ^+, etc.) present on the anode side are irreversible to the cathode side. An ion-exchange membrane is preferred, which allows aggressive movement and allows irreversible movement of anions (eg, Cl ⁻ , SO ₄ ²⁻ , HCO ₃ ⁻ etc.) present on the cathode side to the anode 105 side. Used for That is, by using such an ion exchange membrane, it is possible to efficiently generate functional water suitable for the present invention having characteristics as described below in the vicinity of the anode side.

When the medium containing dioxins is a liquid medium such as water, the amount of water in which the electrolyte is dissolved or the concentration of the dioxin is adjusted so that this solution does not excessively dilute the electrolyte solution in the water tank 101 . It is possible to control the amount of the solution containing the chemicals, etc., and to control the characteristics of the acidic water generated by the electrolysis, such as the hydrogen ion concentration, the oxidation-reduction potential, and the chlorine concentration, within the ranges described above. preferable.
In the dioxin decomposition apparatus having the above configuration,
It is also possible to adopt a configuration in which dioxins contained in the gas phase are introduced into a water tank.

(2) Dioxin having a configuration in which the functional water created by the electrolyzed water generator is transferred to a decomposition treatment tank, dioxins are introduced into the decomposition treatment tank, and both are brought into contact with each other, and light irradiation is performed. FIG. 3 is a schematic view of an embodiment of a dioxin-based decomposer having the above-described configuration. In such an apparatus, the functional water formed by the functional water generator 123 is supplied to the decomposition treatment tank 143 via the pump 145 and the pipe 147. On the other hand, a pump 131 is provided from a tank 137 in which liquid dioxins or a liquid medium in which dioxins are dissolved are stored.
The dioxins are supplied to the decomposition treatment tank 143 via the pipe 133. A stirring device 149 is disposed in the decomposition tank 143, and the mixed liquid is stirred by the stirring device 149. At the same time, the inside of the decomposition treatment tank is irradiated with light by the light irradiation device 166. As a result, the dioxins come into contact with the functional water, the dioxins are decomposed by the functional water, and the decomposition of the dioxins is promoted by light irradiation. In the dioxin decomposing apparatus having such a configuration, as shown in FIG. 3, by providing the stirring means 149 in the decomposition treatment tank 143, the contact efficiency between dioxins and functional water can be improved. It is possible to further improve the decomposition efficiency of dioxins.

In the dioxin decomposition apparatus having the above structure, it is also possible to adopt a structure in which dioxins contained in the gas phase are introduced into a water tank. Further, in the dioxin decomposing apparatus having the above-described configuration, as a means for supplying functional water, instead of the electrolytic water generating apparatus, supply of synthetic functional water comprising an aqueous solution of hypochlorous acid or an aqueous solution of hypochlorite is used. A device in which devices are arranged may be used.

[0028]

EXAMPLES The present invention will be described in detail with reference to the following Examples, which do not limit the present invention in any way. (Example 1) [Example of decomposition of dioxin by configuration of functional water obtained by electrolysis and black light irradiation] First, a strongly acidic functional water generator (trade name: Strong electrolyzed water generator (Model FW-
200; Amano Corporation) to prepare functional water. In this device, a diaphragm is arranged between the anode and the cathode. Functional water of various properties was obtained by using the above apparatus and changing the electrolyte concentration of the water to be electrolyzed and the electrolysis time in various ways. The pH and oxidation-reduction potential of each acidic functional water obtained on the anode side were measured with a pH meter (Toko Chemical Laboratory Co., Ltd., TCX-90i and KP900-2N).
And conductivity meter (Toko Chemical Laboratory Co., Ltd., TCX-
90i and KM900-2N), and the chlorine concentration was measured with chlorine test paper (Advantech).

As a result, the pH of the generated functional water depends on the electrolysis conditions such as the concentration of sodium chloride used as the electrolyte (standard concentration is 1000 mg / l), electrolysis current value, electrolysis time and the like. 0 to 4.0, oxidation-reduction potential is 800 mV to 1500 mV, and chlorine concentration is 5 m
g / l to 150 mg / l were obtained. Therefore, in the present embodiment, as the functional water used for the decomposition experiment of dioxins, the pH is 2.1 and the oxidation-reduction potential is 115.
A functional water having 0 mV and a residual chlorine concentration of 54 mg / l was prepared. This functional water was obtained by setting the electrolyte (sodium chloride) concentration to 1000 mg / l and the electrolysis time to 11 minutes.

Next, the dioxin subjected to the dioxin decomposition experiment was the dioxin measurement kit “DI
OXIN RISC TEST (STRATEGIC
DIAGNOSTICS INC. Model substance 2,3,7-Trichlorodibenzo-p attached to
-Dioxin (TriCDD) was used. This TriCDD
Is 2,3,7,8-Tetrach, a typical dioxin
Although it is a substance with much less toxicity than lorodibenzo-p-dioxin (2,3,7,8-TCDD), it is 2,3,7,8
-Because it can be used as an analytical sample of TCDD,
A (Environmental Protection)
on Agency (Environmental Protection Agency) (National Dioxin Stud)
y, Office of Solid Waste A
nd Emergency Response. EPA
/ 530-SW-87-025. August, 198
7).

10 μl of this TriCDD DMSO solution
Was pipetted into 10 centrifuge tubes by a pipette, DMSO was volatilized by a centrifugal concentrator (manufactured by Tommy Seiko Co., Ltd., CC-100), and then 10 μl of the functional water described above was added to the five centrifuge tubes. Was added, and the light from a black light fluorescent lamp (trade name: FL10BLB; manufactured by Toshiba Corporation, 10 W) was irradiated from a distance of 10 cm from the top while the lid of the centrifuge tube was opened. The light irradiation amount at this time is
Digital UV intensity meter (NT Corporation, UV
A-365), about 0.5 mW / cm ²
Met. In addition, the remaining 5 centrifuge tubes were used as controls.
Pure water (10 μl) was added instead of functional water, and the mixture was left in the same laboratory with the lid open. Sixteen hours later, 10 μl of the DMSO solution is added to each centrifuge tube in which the functional water or pure water has completely evaporated, and the suction / release with a pipette is repeated three times, so that the TriCD in each centrifuge tube is removed.
D was dissolved.

Using this solution as a measurement sample, the residual TriC was measured using the dioxin measurement kit described above.
The concentration of DD was measured. As a result, the average of the TriCDD concentrations of the five control samples was 283.4 ppb.
In contrast, the Tri of the five samples subjected to the decomposition processing is
The average of the CDD concentration is 268.6 ppb, and the sample subjected to the decomposition treatment with a clearly significant difference has a higher TrD.
iCDD concentration was low. Furthermore, the minimum value of the TriCDD concentration of the five samples used as the control exceeded the maximum value of the TriCDD concentration of the five samples subjected to the decomposition treatment, and the addition of functional water produced by electrolysis and the black light It was confirmed that dioxins could be decomposed by light irradiation. Furthermore, the pH and residual chlorine concentration described above were also evaluated for the decomposition of dioxins when using functional water different from the above. It was confirmed that addition of water and light irradiation caused decomposition of dioxins.

Example 2 [Example of Decomposition of Dioxins by Configuration of Functional Water Obtained by Electrolysis and Solar Light Irradiation] Functional water was prepared in the same manner as in Example 1. In this example, functional water having a pH of 2.3, an oxidation-reduction potential of 1050 mV, and a residual chlorine concentration of 50 mg / l was used. Then, similarly to Example 1, 10 μl of the TriCDD DMSO solution was dispensed into ten centrifuge tubes by a pipette, and the centrifugal concentrator (manufactured by Tommy Seiko Co., Ltd.
After volatilizing DMSO by CC-100), 10 μl of the above functional water was added to each of five centrifuge tubes,
The centrifuge tube was left open from 9:00 to 17:00 in a place exposed to direct sunlight from above with the lid open. The amount of light irradiation at this time was measured by a digital ultraviolet intensity meter (manufactured by NT Corporation, UVA-365), and was 0.4
１．２1.2 mW / cm ² . As a control, 10 μl of pure water was added to each of the remaining five centrifuge tubes, and the mixture was left outdoors with the lid open.

Then, 10 μl of DMSO was added to each centrifuge tube in which the functional water or pure water was completely evaporated by the above operation.
The TriCDD in the centrifuge tube was dissolved by repeating the suction / release three times with a pipette.
Then, using this solution as a sample, the concentration of the remaining TriCDD was measured using the dioxin measurement kit described above. As a result, Tr
The average of the iCDD concentration was 288.5 ppb, whereas that of the degraded one was 273.4 ppb.
The riCDD concentration of the sample subjected to the decomposition treatment was clearly significantly lower than that of the sample, and it was found that the dioxins could be decomposed by addition of functional water produced by electrolysis and irradiation with sunlight.

(Example 3) [Decomposition of functional water obtained by electrolysis without diaphragm and dioxin by irradiation of black light] A strongly electrolyzed water generator (Model FW-20) in which the diaphragm between the anode and the cathode was removed
0; manufactured by Amano Co., Ltd.) and variously changing the electrolyte concentration of the water to be electrolyzed, to obtain each functional water as a mixed water obtained on the anode side. The pH and oxidation-reduction potential of each obtained functional water were measured with a pH meter (Toko Chemical Laboratory, T
CX-90i and KP900-2N) and a conductivity meter (Toko Chemical Laboratory Co., Ltd., TCX-90i and KM9)
00-2N), and the chlorine concentration was measured with chlorine test paper (Advantech). As a result, the concentration of sodium chloride used as the electrolyte (standard concentration was 1000 m
g / l), electrolysis current value, electrolysis time, etc., the characteristic value of each functional water is pH 4.0 to 10.0, oxidation-reduction potential is 300 mV to 800 mV, and chlorine concentration is 2 mg / l to 70.
mg / l. Therefore, in this example, functional water having a pH of 7.9, an oxidation-reduction potential of 570 mV, and a residual chlorine concentration of 15 mg / l was prepared as functional water used in an organic compound decomposition experiment. This functional water has an electrolyte concentration of 100.
It was obtained by operating the strong electrolyzed water generator at 0 mg / l for 11 minutes.

The method of decomposition experiment of dioxins was carried out in the same manner as in Example 1. As a result, the average value of the control centrifuge tube was 281.9 ppb, whereas that of the digested tube was 271.2 ppb,
The TriCDD concentration was significantly lower with a significant difference, indicating that dioxins can be decomposed by addition of functional water produced by electrolysis without a diaphragm and irradiation with black light. Furthermore, the pH and residual chlorine concentration described above were also evaluated for the decomposition of dioxins when using functional water different from the above. It was confirmed that addition of water and light irradiation caused decomposition of dioxins.

Example 4 Decomposition of Synthetic Water Prepared with Hydrochloric Acid, Sodium Chloride, and Sodium Hypochlorite and Dioxin by Irradiation with Black Light
1N to 0.1N, sodium chloride 0.005N to 0.0
2N, and sodium hypochlorite 0.0001M to 0.1M.
For each aqueous solution prepared to be 01M, pH,
When the oxidation-reduction potential and the residual chlorine concentration were measured, p
H is 1.0 to 4.0, and the oxidation-reduction potential is 800 mV to 15
00mV, and the residual chlorine concentration is 5mg / l-150mg /
1 and functional water having the same properties as in Example 1 was obtained. Here, hydrochloric acid 0.006N, sodium chloride 0.
When 014N and sodium hypochlorite were set to 0.002M, the pH was 2.3, the oxidation-reduction potential was 1180mV, and the residual chlorine concentration was 105mg / l.

The method of the experiment for decomposing dioxins was carried out in the same manner as in Example 1. As a result, the average value of the control centrifuge tube was 285.7 ppb, whereas that of the digested tube was 270.8 ppb, indicating that the TriCDD concentration between the two was significantly lower with a significant difference. It was found that dioxins can be decomposed by the addition of functional water prepared with an aqueous solution of chlorate or the like and irradiation with black light. Furthermore, when the decomposition of dioxins was evaluated for each functional water prepared with hydrochloric acid, sodium chloride, and sodium hypochlorite having different pH and residual chlorine concentration, the concentration was reduced with time. Decomposition of dioxins by water and light irradiation was confirmed.

[0039]

As described above, according to the present invention,
Provided are a method for decomposing dioxins and an apparatus for decomposing dioxins capable of safely and economically decomposing dioxins under normal temperature and normal pressure.

[Brief description of the drawings]

FIG. 1 is a flow chart showing an outline of a process for decomposing dioxins of the present invention and a process for measuring dioxins in a sample after decomposition.

FIG. 2 is a schematic view of one embodiment of the dioxin decomposition apparatus of the present invention.

FIG. 3 is a schematic view of another embodiment of the dioxin decomposition apparatus of the present invention.

[Description of Signs] 101 : water tank 103: cathode 105: anode 107: diaphragm 109: power supply 111, 115, 147: pipe 109, 113, 117, 131, 145: pump 118: drain pump 119, 137: tank 121: Gas discharge pipe 123: Functional water generator 143: Decomposition tank 149: Stirrer (means) 166: Light source 166 ': Light irradiation device

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C02F 1/58 C02F 1/76 Z 4D061 / 1/76 B01D 53/34 134E F-term (Reference) 2E191 BA12 BD17 4D002 AA21 BA08 BA09 4D037 AA11 AB14 BA18 CA04 CA11 4D038 AA08 AB14 BA04 BB07 BB10 BB16 4D050 AA12 AB19 BB01 BC09 BD06 CA10 4D061 DA08 DB19 DC09 EA03 EB04 ED12 ED17 GA18 GC18

Claims (30)

[Claims] 1. A method for decomposing dioxins, comprising a step of bringing functional water generated by electrolysis of water containing an electrolyte into contact with a medium containing dioxins under light irradiation. 2. The method for decomposing dioxins according to claim 1, wherein the functional water is acidic water generated near an anode by electrolysis of water containing an electrolyte. 3. The method for decomposing dioxins according to claim 1, wherein the functional water is a mixed water of acidic water generated near an anode and alkaline water generated near a cathode by electrolysis of water containing an electrolyte. 4. The method for decomposing dioxins according to claim 3, wherein the mixed water is a mixture of acidic water and alkaline water at a ratio of 1: 1 or less. 5. The method for decomposing dioxins according to claim 1, wherein the electrolyte is at least one of sodium chloride and potassium chloride. 6. A method for decomposing dioxins, comprising the step of contacting functional water containing hypochlorous acid with a medium containing dioxins under light irradiation. 7. The method for decomposing dioxins according to claim 6, wherein the functional water is an aqueous solution of hypochlorite. 8. The method for decomposing dioxins according to claim 7, wherein the hypochlorite is at least one of sodium hypochlorite and potassium hypochlorite. 9. The chlorine concentration of the functional water is 2 to 200 mg / l.
The method for decomposing dioxins according to claim 6, wherein 10. The method for decomposing dioxins according to claim 6, wherein the aqueous hypochlorite solution further contains an inorganic acid or an organic acid. 11. An inorganic or organic acid comprising hydrochloric acid, hydrofluoric acid,
The method for decomposing dioxins according to claim 10, which is at least one selected from oxalic acid, sulfuric acid, phosphoric acid, boric acid, acetic acid, formic acid, malic acid and citric acid. 12. The functional water has a hydrogen ion concentration (pH value).
1-4, redox potential (working electrode: platinum electrode, reference electrode: silver-silver chloride electrode) 800-1500 mV, and
7. The method for decomposing dioxins according to claim 1, wherein the chlorine concentration has a characteristic of 5 to 150 mg / l. 13. The functional water has a hydrogen ion concentration (pH value).
7. The method according to claim 1, wherein the oxidation-reduction potential (working electrode: platinum electrode, reference electrode: silver-silver chloride electrode) is 300 to 1100 mV, and the chlorine concentration is 2 to 100 mg / l. A method for decomposing dioxins. 14. The light for irradiation has a wavelength of 300 to 500 n.
The method for decomposing dioxins according to claim 1 or 6, wherein the method includes light in a wavelength range of m. 15. The method for decomposing dioxins according to claim 14, wherein the light is light in a wavelength range of 350 to 450 nm. 16. The irradiation intensity of light for irradiation is 10 μW /
cm ² ~10mW / cm ² dioxins decomposition method according to claim 1 or claim 6. 17. An irradiation amount of light for irradiation is 50 μW / c.
m ² ~5mW / cm ² a method for decomposing dioxins as claimed in claim 16. 18. The step of bringing functional water generated by electrolysis of water containing an electrolyte into contact with a medium containing dioxins under light irradiation, comprising a pair of electrodes, for applying a potential between the electrodes. A step of preparing a container provided with a power supply and containing water containing an electrolyte therein; a step of causing dioxins to be present at least in the vicinity of the anode of the electrode; The method for decomposing dioxins according to claim 1, comprising a step of electrolyzing to generate functional water; and a step of irradiating the functional water with light. 19. A diaphragm is provided between the electrodes in the container to prevent the functional water generated near the anode and the functional water generated near the cathode from being mixed by electrolysis. The method for decomposing dioxins according to the above. 20. The medium according to claim 19, wherein the medium containing dioxins is in a gaseous state, and the medium containing dioxins is bubbled near the anode so that the medium containing dioxins is present near the anode. A method for decomposing dioxins. 21. The method for decomposing dioxins according to claim 20, wherein bubbling is performed after functional water is generated near the anode. 22. The dioxin-containing medium is in a liquid state, and the dioxin-containing medium is supplied near the anode to cause the dioxins to be present near the anode.
10. The method for decomposing dioxins according to 9. 23. The method for decomposing dioxins according to claim 22, wherein the supply of the medium containing dioxins to the vicinity of the anode is performed after the generation of functional water near the anode. 24. A step of supplying functional water generated near an anode by electrolysis of water containing an electrolyte to a container, a step of supplying a medium containing dioxins to the container, and irradiating the container with light. The method for decomposing dioxins according to claim 1, comprising a step of carrying out. 25. The method for decomposing dioxins according to claim 1, wherein the dioxins are polychlorinated dibenzoparadioxin (PCDD) and polychlorinated dibenzofuran (PCDF). 26. A container containing functional water containing hypochlorous acid, means for irradiating the container with light, and means for supplying a medium containing dioxins to the container. Dioxin decomposition equipment. 27. A decomposition treatment tank, means for supplying functional water generated by electrolysis of water to the decomposition treatment tank, means for supplying dioxins to be decomposed to the decomposition treatment tank,
And a means for irradiating the decomposition treatment tank with light. 28. The method according to claim 27, wherein the means for supplying functional water generated by electrolysis of water to the decomposition treatment tank is a means for supplying functional water generated near the anode by electrolysis of water to the decomposition treatment tank. The disassembly apparatus according to any one of the preceding claims. 29. A container provided with a pair of electrodes and a power supply for applying a potential to the electrodes, a unit for supplying water in which an electrolyte is dissolved to the container, a unit for irradiating light, and a medium containing dioxins A device for decomposing dioxins, comprising: means for supplying dioxins. 30. The decomposition apparatus according to claim 29, wherein the means for supplying the medium containing dioxins is means for supplying dioxins to the anode side of the electrode.