JP2001046548A - Decomposing method for halogenated aliphatic hydrocarbon compound and apparatus used for it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an efficient decomposing method for halogenated aliphatic hydrocarbon compound and apparatus used for it. SOLUTION: This is a decomposing method for halogenated aliphatic hydrocarbon compounds with a process of making functional water and halogenated aliphatic hydrocarbon compounds contact under light irradiation, and a decomposing method having a process of making functional water containing decomposed products of halogenated aliphatic hydrocarbon compounds, contact with a photocatalyst and an apparatus used for it.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for decomposing a halogenated aliphatic hydrocarbon compound and an apparatus used therefor.

[0002]

2. Description of the Related Art Halogenated aliphatic hydrocarbon compounds (eg, chlorinated ethylene, chlorinated methane, etc.) have been used enormously with the recent development of industrial technology, and their disposal has become a serious problem. . In addition, these gases used have caused environmental problems such as polluting the natural environment, and great efforts have been made to solve them.

[0003] Specific treatment methods include, for example, a method of decomposing chlorinated ethylene using an oxidizing agent or a catalyst, a method of decomposing with ozone (JP-A-3-38297) or an ultraviolet ray in the presence of hydrogen peroxide. Is known (Japanese Patent Application Laid-Open No. 63-218293). It has also been suggested to use sodium hypochlorite as an oxidizing agent (US Pat. No. 5,525,008, 561164).
2). A method of combining sodium hypochlorite with ultraviolet irradiation has also been proposed (US Pat. No. 5,558,274).
1). Furthermore, a method is known in which a photocatalyst comprising fine particles of an oxide semiconductor such as titanium oxide and liquid chlorinated ethylene are suspended under alkaline conditions and decomposed by light irradiation (Japanese Patent Application Laid-Open No. 7-141373).

[0004] In addition to the above, a photolysis method of irradiating ultraviolet rays in a gas phase without using an oxidizing agent has already been attempted. For example, a method in which an exhaust gas containing an organic halogen compound is irradiated with ultraviolet rays to form an acidic decomposition gas, then washed with an alkali and detoxified (Japanese Patent Application Laid-Open No. 62-191025), a wastewater containing an organic halide is used. Aeration process,
An apparatus for irradiating the discharged gas with ultraviolet rays and then performing alkali cleaning (Japanese Patent Laid-Open No. 62-191095) has been proposed. Further, as an example presumed to be reductive decomposition, chlorinated ethylene decomposition by iron powder is also known (JP-A-8-257570). Regarding the decomposition of PCE (perchlorethylene: the same applies hereinafter) using silicon fine particles, reductive decomposition has also been reported.

[0005] However, none of these methods can be said to be sufficiently practical in terms of the decomposition efficiency and the equipment configuration required for the treatment, etc., and can be used to efficiently decompose the halogenated aliphatic hydrocarbon compound with a simpler equipment configuration. There is a need for a way to do that.

[0006]

The inventors of the present invention have studied the methods for decomposing various halogenated aliphatic hydrocarbon compounds as described above, and as a result, it is expected that each of them contains an unsolved problem. Therefore, there are fewer problems,
It was concluded that there was a need for technology for the environmentally friendly decomposition of halogenated aliphatic hydrocarbon compounds.

[0007] The present invention has been made based on new findings by the present inventors, and has as its object the purpose of being more environmentally friendly and having a lower possibility of causing new environmental pollution by decomposition. An object of the present invention is to provide a method for efficiently decomposing a hydrocarbon compound and an apparatus used for the method.

In particular, it is an object of the present invention to provide a cheaper and simpler technique without using an expensive and high-energy light source and accompanying expensive materials such as quartz.

[0009]

Investigations were made to achieve the above-mentioned problems. As a result, a disinfection effect (Japanese Patent Publication No. JP-A-180293) and a cleaning effect for contaminants on a semiconductor wafer (Japan) Patent publication 1995 51675
Functional water obtained by electrolysis of water reported to have, for example, acidic functional water, has excellent halogenated aliphatic hydrocarbon compound resolution under light irradiation. Obtained knowledge.

[0010] After that, a more practical form was examined, and as the detailed experiments proceeded, the contamination containing the acidic functional water and the halogenated aliphatic hydrocarbon compound obtained by the electrolysis through the diaphragm as described above was carried out. When decomposing the substance under light irradiation, or after the decomposition, it is desirable that the decomposition treatment liquid be in contact with a photocatalyst such as TiO ₂ under light irradiation. It has been found that a similar effect can be obtained by using functional water containing an acid, and the present invention has been achieved.

That is, a method for decomposing a halogenated aliphatic hydrocarbon compound according to one embodiment of the present invention comprises a step of bringing functional water into contact with a contaminant containing a halogenated aliphatic hydrocarbon compound under light irradiation. A method for decomposing a fluorinated aliphatic hydrocarbon compound, wherein functional water containing a decomposition product after the light irradiation treatment is brought into contact with a photocatalyst under light irradiation.

A means for supplying functional water to the decomposition treatment layer; a means for supplying a contaminant containing a halogenated aliphatic hydrocarbon compound to be decomposed to the decomposition treatment layer; and irradiating the decomposition treatment layer with light. An apparatus for decomposing a halogenated aliphatic hydrocarbon compound, wherein a photocatalyst coexists in the decomposition tank in the apparatus for decomposing a halogenated aliphatic hydrocarbon compound having a means for performing the following.

In another embodiment, the apparatus for decomposing a halogenated aliphatic hydrocarbon compound includes a means for supplying functional water to a first decomposition treatment layer, a contaminant containing a halogenated aliphatic hydrocarbon compound to be decomposed. From the first decomposition treatment tank of the halogenated aliphatic hydrocarbon compound having means for supplying the first decomposition treatment layer to the first decomposition treatment layer and means for irradiating the first decomposition treatment layer with light. An apparatus for decomposing a halogenated aliphatic hydrocarbon compound, comprising: means for supplying a decomposition treatment liquid containing a substance to a second decomposition treatment tank; and means for irradiating the second decomposition treatment tank with light. A photocatalyst is provided inside the layer, and the functional water containing the decomposition product is brought into contact with the photocatalyst.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION According to one embodiment of the present invention, a method for decomposing a halogenated aliphatic hydrocarbon compound comprises bringing functional water into contact with a halogenated aliphatic hydrocarbon compound to be decomposed under light irradiation. And a step of contacting the decomposition product generated at this time with a photocatalyst such as TiO2 under light irradiation to decompose the product.

(Halogenated aliphatic hydrocarbon to be decomposed
Elemental compound) Examples of the halogenated aliphatic hydrocarbon compound to be decomposed include chlorinated ethylene and chlorinated methane. Specifically, examples of the chlorinated ethylene include 1 to 4 chlorine-substituted products of ethylene, that is, chloroethylene, dichloroethylene, trichloroethylene, and tetrachloroethylene. Further, as dichloroethylene, for example, 1,1-dichloroethylene (vinylidene chloride), cis-1,2-dichloroethylene, tras-
1,2-dichloroethylene methane can be mentioned. As chlorinated methane, chlorine-substituted methane,
For example, chloromethane, dichloromethane, trichloromethane and the like can be mentioned.

(Regarding functional water) Functional water means, for example, a hydrogen ion concentration (pH value) of 1 to 4 and an oxidation-reduction potential of 800 mV or more when a working electrode is a platinum electrode and a reference electrode is silver-silver chloride. 1500 mV or less, preferably 1000 mV or more and 1300 mV or less, and chlorine concentration of 5 mg / L or more and 150 mg / L or less, preferably 30 mV
It refers to water having properties of g / L or more and 120 mg / L or less.

Such functional water is obtained by dissolving an electrolyte (for example, sodium chloride, potassium chloride, etc.) in raw water and subjecting this water to electrolysis in a water tank having a pair of electrodes on which a diaphragm is disposed, so that the vicinity of the anode can be obtained. Can be obtained at Here, the concentration of the electrolyzed water in the raw water before the electrolysis is, for example, preferably 20 mg / L to 2000 mg / L, more preferably 200 mg / L to 1000 mg / L for sodium chloride, and the electrolysis current value at that time is 2 A to It is desirable to be 20A.

As the diaphragm, for example, an ion exchange membrane is preferably used. As a means for obtaining such functional water, a commercially available strongly acidic electrolyzed water generator (for example, trade name:
Oasis Bio Half; Asahi Glass Engineering Co., Ltd.
Product name: Strong electrolyzed water generator (Model FW-2)
00); manufactured by Amano Corporation.

(Synthetic functional water) Functional water having a halogenated aliphatic hydrocarbon resolving power substantially equivalent to the functional water generated by the above-mentioned electrolysis is prepared not only by electrolysis but also by dissolving various reagents in raw water. It is also possible. 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, it can be obtained by using 0.001 N to 0.1 N hydrochloric acid, 0.001 N to 0.1 N sodium hydroxide, and 0.0001 M to 0.01 M sodium hypochlorite. It can also be obtained by using only chlorate, for example, sodium hypochlorite at 0.0001M to 0.01M. 3. pH of 4 with hydrochloric acid and hypochlorite.
Functional water having a chlorine concentration of 2 mg / l or more at 0 or less can be adjusted. Functional water can also be produced using N ₃ C ₃ O ₃ NaCl ₂ or the like which is commercially available as a weakly acidic water powder generator (for example, Quinosan 21X (trade name, manufactured by Clean Chemical Co., Ltd.)). Functional water from these chemical preparations also has the ability to decompose halogenated aliphatic hydrocarbons by irradiating light, as in the case of functional water by electrolysis, although there is a difference in the decomposing ability as is clear from the examples. . Here, the raw water includes tap water, river water, seawater, and the like. The pH of these waters is usually between 6 and 8 and the chlorine concentration is at most less than 1 mg / l, and such raw water naturally has the resolution of halogenated aliphatic hydrocarbons as described above. Not.

(Regarding Light Source) The light to be irradiated when decomposing the halogenated aliphatic hydrocarbon compound and its product by the functional water and the photocatalyst is, for example, a wavelength of 300 to 50.
Light having a wavelength of 0 nm, particularly 350 to 450 nm is preferable. The light irradiation intensity is, for example, several hundred μW / cm ² (300 nm to 400 nm) in a light source having a peak at a wavelength of 365 nm.
(Measurement is performed), the decomposition is practically sufficient. And
Natural light (for example, sunlight) is used as a light source for such light.
Alternatively, artificial light (a mercury lamp, a black light, a color fluorescent lamp, or the like) can be used.

The light irradiation may be performed directly on the functional water, or may be performed through a transparent container made of glass, plastic, or the like. In order to perform the decomposition effectively, it is desirable to perform light irradiation when the functional water and the halogenated aliphatic hydrocarbon compound and the photocatalyst and the decomposition product come into contact with each other. Further, in the present embodiment, it is not necessary to use ultraviolet light having a wavelength of about 250 nm which has a large effect on the human body as light.

(Decomposition of decomposition products by photocatalyst
T) Decomposition of halogenated aliphatic hydrocarbon compounds by functional water may not be completely decomposed. For example TCE
This produces degrading organisms such as dichloroacetic acid, which results when is decomposed by acidic water. Such decomposition products can be removed by way of contact with a photocatalyst such as TiO ₂ under light irradiation.

A photocatalyst such as TiO ₂ is originally activated by light (ultraviolet) energy to generate a strong oxidizing power, and has a property of oxidizing and decomposing many organic substances in contact with the surface.
As the photocatalyst used here, oxides such as TiO ₂ , zinc oxide and tungsten trioxide, metal sulfides such as cadmium sulfide and zinc sulfide, or a catalyst obtained by adding platinum, gold, palladium or the like to these can be used. . Alumina, silica with a large surface area with adsorptive power as a form,
Photocatalysts corresponding to various uses such as powders, sols, sheet filters, honeycomb filters, etc., in which the above-mentioned photocatalyst component such as TiO ₂ is supported on the surface of activated carbon or the like, especially TiO ₂ are already commercially available. It is preferable to appropriately select a form capable of sufficiently exhibiting the decomposition ability.

In general, TiO ₂ which is relatively inexpensive and has no toxicity and is easy to handle is most preferably used in the present invention.

An apparatus for decomposing a halogenated aliphatic hydrocarbon compound used for decomposing a halogenated aliphatic hydrocarbon compound using functional water will be described below. Examples of the apparatus for decomposing halogenated aliphatic hydrocarbon compounds include the following 1) and 2).

1) After the halogenated aliphatic hydrocarbon compound is decomposed by functional water under light irradiation in the first decomposition tank, the decomposition treatment liquid is transported to the second decomposition tank, and TiO is irradiated under light irradiation.
Decomposition of decomposition products in the decomposition treatment liquid by ₂ is performed.

FIG. 1 is a schematic view of one embodiment of the apparatus for decomposing a halogenated aliphatic hydrocarbon compound according to the present invention. In FIG. 1, reference numeral 4 denotes a functional water generator, which has a cathode 6 and an anode 5, a diaphragm 7 such as an ion exchange membrane, and a power source 34 connected to the electrodes. 1 is a tank for storing an aqueous electrolyte solution, 3 and 35 are pipes and pumps for supplying water containing an electrolyte into the water tank, 10 is a supply of a halogenated aliphatic hydrocarbon compound to be decomposed or a medium containing the same. And 12 are pipes and pumps for supplying a halogenated aliphatic hydrocarbon compound from the pollutant supply tank 10 to the first cracking tank, and 15 is a halogenated aliphatic hydrocarbon by functional water. A first decomposition tank for decomposing compounds, 16-1 is a light irradiation device of the first decomposition tank, 13 and 14 are pipes and pumps for supplying functional water to the first decomposition tank, and 21 is a first decomposition tank. A second decomposition tank 22 for decomposing a decomposition treatment liquid containing decomposition products discharged from TiO ₂ with TiO ₂ is provided with a TiO ₂ for decomposing decomposition products.
₂ , 16-2 are light irradiation devices for the second decomposition tank, and 19 and 20 are pipes and pumps for supplying a decomposition treatment liquid containing decomposition products discharged from the first decomposition tank to the second decomposition tank. Have.

Then, the water in which the electrolyte is dissolved is supplied to the functional water generator 4 through the pipe 3, and the functional water generator 4 is filled with the water in which the electrolyte is dissolved. When power is supplied from the power supply 34 to the electrodes 6 and 5 for electrolysis, acidic functional water is generated on the anode 5 side. This acidic functional water is supplied to the first decomposition tank 15 through the pipe 13. Further, the halogenated aliphatic hydrocarbon compound or a medium containing the same is supplied to the first cracking tank through the pipe 11, and the first cracking tank is filled with the acidic functional water and the halogenated aliphatic hydrocarbon compound or a medium containing the same. .

In mixing the acidic functional water with the halogenated aliphatic hydrocarbon compound or a medium containing the same, the concentration of the electrolyte and the amount of the solution containing the halogenated aliphatic hydrocarbon compound are adjusted so that the acidic functional water is not excessively diluted. Control the
It is preferable to control the characteristics of the acidic functional water so as to be in the above-mentioned range.

Light is irradiated by the light source 16-1 installed in the first decomposition tank. Here, the halogenated aliphatic hydrocarbon compound is brought into contact with the acidic functional water, and its decomposition is promoted by light irradiation. After the completion of the decomposition treatment, the decomposition treatment liquid is sent to the second decomposition tank through the pipe 19 and the pump 20. Light is irradiated by the light source 16-2 installed in the second decomposition tank. Here, the decomposition products in the decomposition solution are accelerated by the photocatalysis of TiO ₂ . After the end of this decomposition, it is discharged from 36.

FIG. 2 is a schematic view of an embodiment of a decomposition apparatus in which the decomposition target is a gaseous halogenated aliphatic hydrocarbon compound. In FIG. 2, 1 is a tank for storing an aqueous electrolyte solution, 4 is a functional water generator, 15 is a first decomposition tank for photodecomposing halogenated aliphatic hydrocarbon compounds with acidic functional water, and 28 is a decomposition treatment in the first decomposition tank. Activated carbon column for final treatment of the gas thus obtained, 26 is an introduction pipe for introducing the gas decomposed in the first decomposition tank into the activated carbon column 28, 21 is TiO ₂ and discharged from the first decomposition tank 15 A second decomposition tank for photolysis of decomposition products, 25 a contaminant supply device for supplying air containing a halogenated aliphatic hydrocarbon compound, 3 an introduction pipe for introducing an aqueous electrolyte solution into the functional water generation device 4, 13 and 14 are an introduction pipe and a pump for introducing the acidic functional water into the first decomposition tank 15, and 11 and 12.
Denotes an inlet pipe and a pump for introducing air containing a halogenated aliphatic hydrocarbon compound into the first cracking tank, and 19 and 20 denote a second processing liquid containing a cracked product discharged from the first cracking tank 15.
The introduction pipe and pump introduced into the decomposition tank, 26 and 27 are the first
An introduction pipe and a pump for introducing the gas decomposed in the decomposition tank into the activated carbon column 28, 16-1 is a light irradiation device of the first decomposition tank, 16-2 is a light irradiation device of the second decomposition tank, 23
Is an exhaust port for a gas in which the halogenated aliphatic hydrocarbon compound and its decomposition product are decomposed. Among the decomposition products of the halogenated aliphatic hydrocarbon compound decomposed in the first decomposition tank, gaseous substances are adsorbed and removed by the activated carbon column, and water-soluble substances are sent to the second decomposition tank together with acidic functional water. Ti
It is discharged after being subjected to photodecomposition treatment by O ₂ .

2) Functional water and a halogenated aliphatic hydrocarbon compound to be decomposed are introduced into a decomposition tank in which TiO ₂ is disposed, and decomposition of the halogenated aliphatic hydrocarbon compound under light irradiation and decomposition products are performed. Is re-decomposed with a photocatalyst such as TiO ₂ in the same apparatus.

FIG. 3 is a schematic view of another embodiment of the apparatus for decomposing a halogenated aliphatic hydrocarbon compound. The acidic functional water formed on the anode side by the functional water generator 3 is supplied to the decomposition tank 15 via the pump 14 and the pipe 13. The halogenated aliphatic hydrocarbon compound is supplied from the contaminant supply tank to the decomposition tank 30 via the pipe 11 and the pump 12. TiO ₂ 22 is disposed in the cracking tank, and the operation of the light irradiation device 16 starts the decomposition of the halogenated aliphatic hydrocarbon compound by the acidic functional water, and at the same time, the decomposition product of the halogenated aliphatic hydrocarbon compound. Is promoted by the photocatalysis of TiO ₂ .

FIG. 4 is a schematic view of another embodiment of the apparatus for decomposing a halogenated aliphatic hydrocarbon compound. The acidic functional water formed on the anode side by the functional water generator 4 is used to decompose gaseous halogenated aliphatic hydrocarbon compounds, and is supplied to the decomposition tank 30 via the pump 14 and the pipe 13. The gaseous halogenated aliphatic hydrocarbon compound is supplied from the pollutant supply tank to the pipe 13 and the pump 14.
And supplied to the decomposition tank. TiO ₂ 2 in the decomposition tank
2, the operation of the light irradiation device 16 starts the decomposition of the halogenated aliphatic hydrocarbon compound by the acidic functional water, and at the same time, the decomposition product of the halogenated aliphatic hydrocarbon compound is a photocatalyst such as TiO ₂ Decomposition is promoted by photocatalysis.

FIG. 5 is a schematic view of another embodiment of the apparatus for decomposing a halogenated aliphatic hydrocarbon compound. In order to decompose the medium containing the halogenated aliphatic hydrocarbon compound in a continuous system, six decomposition tanks were provided so that the acidic functional water and TiO ₂ could sufficiently contact the halogenated aliphatic hydrocarbon compound. The acidic functional water formed on the anode side by the functional water generator 4 is continuously supplied at a desired flow rate to the decomposition tank 30-1 via the pump 14 and the pipe 13. The halogenated aliphatic hydrocarbon compound is supplied from the pollutant supply tank 10 to the supply pipe 1.
1 and the pump 12 are continuously supplied to the decomposition treatment tank 30-1 at a desired flow rate, and the light irradiation device 16-
1 irradiates the inside of the decomposition treatment tank 30-1 with light. The decomposition treatment tank 30-1 comes into contact with the halogenated aliphatic hydrocarbon compound and the functional water, and accelerates the decomposition treatment by light irradiation. Further, the TiO ₂ 22 disposed in the decomposition treatment tank 30-1 comes into contact with the decomposition product of the halogenated aliphatic hydrocarbon compound, and T
The decomposition process is promoted by the photocatalysis of iO ₂ . The same decomposition as the decomposition treatment layer 30-1 is performed in the decomposition treatment layers 30-2 to 30-30.
The processing solution that has been completely purified by repeating at -6
Is discharged from

1 to 5, the functional water generator 4 may be replaced with a hypochlorous acid aqueous solution or a hypochlorite aqueous solution supply device.

The decomposition apparatus which can be used to decompose the halogenated aliphatic hydrocarbon compound using functional water, TiO ₂ and light irradiation has been described above. In view of this, a configuration in which a diaphragm such as an ion exchange membrane in the tank is removed can be adopted. That is, functional water generated from an apparatus having no diaphragm can also be used for the decomposition of the above-described halogenated aliphatic hydrocarbon compounds.

Although various embodiments according to the present invention have been specifically described above, it is needless to say that the present invention is not limited to these embodiments.

Hereinafter, the present invention will be described in detail with reference to examples.

[0041]

(Example 1) (Electrolytic functional water of TCE,
Photo) decomposition + (TiO ₂ , photo) decomposition First, functional water was prepared using a strongly acidic functional water generator (trade name: Strong electrolyzed water generator (Model FW-200; manufactured by Amano Corporation)). In this example, a diaphragm is disposed between the anode and the cathode, and in this embodiment, pH is used as functional water for a decomposition experiment of TCE (trichloroethylene, the same applies hereinafter).
2.1, redox potential 1150 mV, residual chlorine concentration 64
mg / liter of functional water was prepared. The functional water was obtained by setting the electrolyte (sodium chloride) concentration to 1000 mg / l and the electrolysis time to 11 minutes. Then 27.
Six 5 ml glass vials were prepared, and 10 ml of functional water was put into each glass vial and sealed with a butyl rubber stopper with a Teflon liner and an aluminum seal. Next, TCE gas was added to all the glass vials through a butyl rubber stopper with a gas-tight syringe so that the TCE concentration when all of the TCE in the glass vials was dissolved in the functional water was 30 ppm. Light from a lamp (trade name: FL10BLB; manufactured by Toshiba Corporation, 10 W) was applied. The irradiation light amount is 0.8mW / cm ² -1.2mW /
cm ² .

After one hour, the TCE concentration of the gas phase in each glass vial was measured. The TCE concentration of the gas phase in the glass vial was measured by sampling the gas phase of the glass vial with a gas tight syringe,
E concentration was measured by gas chromatography (trade name: GC-14
B (with FID detector); TCE was not detected in any of the vials when the column was measured using Shimadzu Corporation (DB-624, manufactured by J & W).

Next, three of the six vials were subjected to MTBE solution extraction, methylated, and then measured by gas chromatography with an ECD detector. From all the vials, it was considered to be a decomposition product of TCE. Dichloroacetic acid was detected. The average concentration of dichloroacetic acid detected was 26.6 ppm.

Next, TiO was added to the remaining three vials.
₂ 0.5 g of ST-B11 (manufactured by Ishihara Sangyo Co., Ltd.) was added and sealed again with an aluminum seal. After irradiation with a black light fluorescent lamp (irradiation light amount: 0.8 mW / cm ^{2 to} 1.2 mW / cm ² ) for one hour, MTBE (methyl-t
er-butyl ether: the same applies hereinafter). After solution extraction and methylation and measurement by gas chromatography with an ECD detector, the average concentration of dichloroacetic acid detected from three vials was 0.02 ppm.

(Example 2) TCE (electrolytic functional water,
TiO _2, light) was prepared functional water by using the same apparatus as the decomposition Example 1. p
With respect to H, oxidation-reduction potential, and residual chlorine concentration, those similar to those in Example 1 were prepared. Next, three 27.5 ml glass vial bottles were prepared, and each glass vial was filled with 10 ml of functional water and TiO ₂ (ST-ST manufactured by Ishihara Sangyo Co., Ltd.).
B11) 0.5 g was put therein, and sealed with a butyl rubber stopper with a Teflon liner and an aluminum seal. Next, the TCE when all the TCE in the glass vial was dissolved in functional water
After the TCE gas was added to all the glass vials through a butyl rubber stopper with a gas-tight syringe so that the concentration became 30 ppm, light from a black light fluorescent lamp was irradiated for 1 hour in the same manner as in Example 1.

Next, when the TCE concentration of the gas phase portion in each glass vial was measured by gas chromatography with an FID detector, no TCE concentration was detected.

Further, for each vial bin, the MT
Extraction of the BE solution was followed by methylation and measurement by gas chromatography with an ECD detector. The concentration of the detected dichloroacetic acid was 0.03 ppm on average.

Example 3 (Hydrochloric acid, sodium chloride,
Water + TiO ₂ prepared with sodium and sodium hypochlorite
+ Photolysis) For an aqueous solution prepared to be 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 in pure water, pH, When the oxidation-reduction potential and the residual chlorine concentration were measured, the pH changed from 1.0 to 4.0, the oxidation-reduction potential changed from 800 mV to 1500 mV, and the residual chlorine concentration changed from 5 mg / l to 150 mg / l. Functional water having the same properties as was obtained. Here, hydrochloric acid 0.00
When 5N, 0.01N sodium chloride, and 0.0018M sodium hypochlorite were used, the pH was 2.3, the oxidation-reduction potential was 1180mV, and the residual chlorine concentration was 75mg / l. This functional water was used for experiments. The experimental method was the same as in Example 2.

10 ml of functional water in three glass vials
And TiO2 (ST-B11 manufactured by Ishihara Sangyo Co., Ltd.) 0.5
g, sealed with a butyl rubber stopper with a Teflon liner and an aluminum seal, added with a gas tight syringe so that the TCE concentration became 30 ppm, and then irradiated with light from a black light fluorescent lamp for 1 hour in the same manner as in Example 1.

Next, when the TCE concentration of the gas phase portion in each glass vial was measured by gas chromatography with a FID detector, no TCE concentration was detected.

Further, for each vial bin, the MT
The BE solution was methylated after extraction and measured by gas chromatography with an ECD detector. The concentration of the detected dichloroacetic acid was 0.02 ppm on average.

Example 4 Decomposition of Synthetic Contaminated Liquid The apparatus shown in FIG. 1 was prepared. An electrolyte (sodium chloride solution) 2 is prepared in an electrolyte supply tank 1 and a strongly acidic functional water generator 4 (trade name: strong electrolyzed water generator (Mode)
l FW-200; manufactured by Amano Corporation). In the strongly acidic functional water generator, a diaphragm 7 is disposed between an anode 5 and a cathode 6. The functional water used in this experiment had a pH of 2.1 and an oxidation-reduction potential of 11 under the conditions of an electrolyte (sodium chloride) concentration of 1000 mg / liter and an electrolysis time of 11 minutes.
Functional water having a concentration of 50 mV and a residual chlorine concentration of 64 mg / liter was prepared. Further, a synthetic contaminated liquid 9 shown below was prepared and placed in a contaminated liquid supply tank 10.

Composition of synthetic contaminated liquid: TCE 200 mg PCE 200 mg Chloroform 200 mg Water 1 liter And, it was supplied to the first decomposition tank 15 (capacity: 1 liter) by the transport pump 12.

Next, the functional water and the synthetic contaminated liquid were supplied to the feed pipe 1.
3 and 11, the first using transfer pumps 14 and 12
Supply 500ml each to the decomposition tank, light irradiation means 16-1
(Black light fluorescent lamp (TOSHIBA, FL10BL
B, 10w)), irradiation was performed in the first decomposition tank for 30 minutes. A treatment liquid is collected from a sampling port 18 provided in a drain port 17 of the first decomposition tank, and TCE,
When the concentrations of PCE and chloroform were measured by gas chromatography with an ECD detector, each was 0.02 p.
pm, 0.03 ppm and 0.03 ppm, and the concentration of dichloroacetic acid was 80 ppm.

Next, the processing liquid is supplied from the first decomposition tank to the feed pipe 1.
9 and transported to a second decomposition tank (capacity: 1 liter) 21 containing TiO ₂ (100 g) 22 and irradiated with light 16-2.
(Black light fluorescent lamp (TOSHIBA, FL10BL
B, 10w)), irradiation in the decomposition tank was performed for 30 minutes.
The solution after the treatment was sampled from the sampling port 23 and measured for dichloroacetic acid. The result was 0.02 ppm.

Example 5 Decomposition of Contaminated Gas The apparatus shown in FIG. 2 was prepared. For the generation of functional water, a strongly acidic functional water generator 4 (trade name: strong electrolyzed water generator (Model FW-200; Amano Corporation) similar to that used in Example 1
(Manufactured by Sharp Corporation). The functional water used in this experiment had a pH of 2.1 and an oxidation-reduction potential of 11 under the conditions of an electrolyte (sodium chloride) concentration of 1000 mg / liter and an electrolysis time of 11 minutes.
A functional water having a concentration of 50 mV and a residual chlorine concentration of 64 mg / liter was prepared.
000 ml) 15. On the other hand, the gas phase concentration is 1500
Air containing ppm of TCE was continuously supplied to the lower part of the decomposition column 15 at a flow rate of 10 ml / min from a gas supply device 25 (standard gas generator, Gastec, PD-1B).

Irradiation in the decomposition column was carried out for 30 minutes using light irradiation means 16-1 (black light fluorescent lamp (FL10BLB, 10w, manufactured by Toshiba)). The exhaust gas was sampled from a sampling port 27 provided at the exhaust port 26 of the first decomposition column with a gas tight syringe, and the concentration of TCE was measured by gas chromatography with an FID detector. In addition, drain port 1 of the first decomposition column
The treatment liquid was collected from the sampling port 18 of No. 7 and the concentration of dichloroacetic acid was measured. As a result, it was 2.1 ppm.

Next, the processing liquid is supplied from the first decomposition tank to the feed pipe 1.
9 and transported to a second decomposition tank 21 (capacity: 1 liter) containing TiO ₂ (100 g) 22 by light irradiation means 16-2 (black light fluorescent lamp (manufactured by Toshiba, FL10BLB, 10).
In w)), irradiation in the decomposition tank was performed for 30 minutes. The solution after the treatment was collected from the sampling port 23 and measured for dichloroacetic acid. The result was 0.03 ppm.

(Example 6) Synthetic fouling with functional water + TiO ₂
Continuous Decomposition of Stained Water Decomposition experiments of synthetic contaminated water were performed using the decomposition apparatus shown in FIG. As the strongly acidic functional water generator 4, the same apparatus as used in Example 1 was used, and the pH obtained on the anode side was used.
2.1, redox potential 1150 mV, residual chlorine concentration 54
A functional water 8 having a mg / liter was made. On the other hand, synthetic contaminated water 9 shown below was prepared and put into the contaminated tank 10.

Composition of synthetic contaminated liquid: TCE 600 mg PCE 300 mg Chloroform 100 mg dichloromethane 100 mg water 1 liter To increase the average residence time of synthetic contaminated water, the decomposition columns 30-1 to 6 are each a column having an inner diameter of 25 mm, a length of 1 m, and a volume of about 490 ml. The column was connected to a total volume of about 2940 ml, and the column was filled with 25 g of TiO ₂ 22 per column.
In order that the synthetic contaminated water and the irradiation light can sufficiently contact the TiO ₂ ,
All columns are set horizontally, and the light irradiation means 16-1 to 16-1
6 black light fluorescent lamp (trade name: FL10
BLB; 10w), manufactured by Toshiba Corporation, was arranged in parallel with the column so that the entire decomposition column could be uniformly irradiated with light.

Next, after the functional water is supplied by the feed pipe 13 and the pump 14 until the functional water fills the entire decomposition column,
The solution was continuously supplied to the decomposition column at a flow rate of 5 ml / min. Next, the synthetic contaminated water was supplied to the pump 12 and the feed pipe 1.
1 and a continuous decomposition column 3 at a flow rate of 5 ml / min.
0-1. Further, the light irradiating means 16-1 to 16-6 are set to 0.1.
Light irradiation was performed at 8 to 1.2 mW / cm ² . The contaminant concentration of the treatment liquid discharged from the outlet 32 of the decomposition column 16-6 was measured by hexane extraction and MTBE extraction-methylation, and the concentration of each contaminant was 0.02 pp TCE.
m, PCE 0.03 ppm, chloroform 0.025 ppm,
0.03 ppm of dichloromethane, 0.03 ppm of dichloroacetic acid
It was found that this apparatus can highly decompose synthetic contaminated liquid.

[0062]

As described above, according to the present invention, it is possible to stably, safely and economically decompose a halogenated aliphatic hydrocarbon at normal temperature and normal pressure.

[Brief description of the drawings]

FIG. 1 is a schematic view of a halogenated aliphatic hydrocarbon cracking apparatus according to one embodiment of the present invention.

FIG. 2 is a schematic view of a gaseous halogenated aliphatic hydrocarbon cracking apparatus according to another embodiment of the present invention.

FIG. 3 is a schematic view of a halogenated aliphatic hydrocarbon cracking apparatus according to another embodiment of the present invention.

FIG. 4 is a schematic view of a gaseous halogenated aliphatic hydrocarbon cracking apparatus according to another embodiment of the present invention.

FIG. 5 is a schematic view of a continuous halogenated aliphatic hydrocarbon cracking apparatus according to another embodiment of the present invention.

FIG. 6 is a sectional view of the decomposition tank of FIG.

[Explanation of symbols]

Reference Signs List 1 electrolyte aqueous solution storage tank 2 electrolyte water 3 pipe 4 functional water purifier 5 negative electrode 6 positive electrode 7 diaphragm 8 functional water 9 halogenated aliphatic hydrocarbon-containing solution 10 contaminated water supply tank 11 pipe 12 pump 13 pipe 14 pump 15th 1 decomposition tank 16 light irradiation device 17 drain port 18 sampling port 19 pipe 20 pump 21 second decomposition tank 22 TiO ₂ 23 sampling port 24 halogenated aliphatic hydrocarbon-containing gas 25 pollutant gas supply tank 26 pipe 27 sampling port 28 activated carbon column 30 decomposition tank 31 pipe 32 pipe 33 treated water 34 power supply 35 pump 36 pipe 37 bubbler

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2E191 BA15 BC01 BD13 BD17 4D061 DA08 DB10 DC09 EA02 EB13 EB19 EB30 EB31 EB37 EB39 ED13 ED17 ED20 FA11 GA07 GC06 GC14 4H006 AA04 AA05 AC26 BA28 BA29 BA35 BA36 BA37 BA50 BA66 BA BD81 BE36 BE60

Claims (20)

[Claims] 1. A method for decomposing a halogenated aliphatic hydrocarbon compound, comprising the step of bringing functional water and a halogenated aliphatic hydrocarbon compound into contact with each other under light irradiation. A method for decomposing a halogenated aliphatic hydrocarbon compound, comprising a step of bringing functional water containing a decomposition product into contact with a photocatalyst under light irradiation. 2. The step of contacting the decomposition product of the halogenated aliphatic hydrocarbon compound with a photocatalyst under light irradiation, the step of contacting functional water with the halogenated aliphatic hydrocarbon compound under light irradiation. 2. The method for decomposing a halogenated aliphatic hydrocarbon compound according to claim 1, wherein the method is performed in the same step. 3. Decomposition of the halogenated aliphatic hydrocarbon compound after passing through a step of bringing functional water into contact with the halogenated aliphatic hydrocarbon compound under light irradiation to decompose the halogenated aliphatic hydrocarbon compound. The method for decomposing a halogenated aliphatic hydrocarbon compound according to claim 1, wherein the functional water containing the substance is brought into contact with the photocatalyst under light irradiation. 4. The decomposition method according to claim 1, wherein the functional water is acidic water generated near an anode by electrolysis of water containing an electrolyte. 5. The decomposition method according to claim 1, wherein the electrolyte is at least one of sodium chloride and potassium chloride. 6. The method according to claim 1, wherein said functional water is an aqueous solution of hypochlorite. 7. The method according to claim 6, wherein said hypochlorite is at least one of sodium hypochlorite and potassium hypochlorite. 8. The functional water having a chlorine concentration of 2 to 200 mg /
7. The decomposition method according to claim 6, wherein l is 1. 9. The decomposition method according to claim 6, wherein the aqueous solution further contains an inorganic acid. 10. The method according to claim 10, wherein the inorganic acid is hydrochloric acid, hydrofluoric acid, oxalic acid,
The decomposition method according to claim 9, which is at least one selected from sulfuric acid, phosphoric acid, and boric acid. 11. The functional water has a hydrogen ion concentration (pH value).
4. A redox potential (working electrode: platinum electrode, reference electrode: silver-silver chloride electrode) of 800 to 1500 mV, and a chlorine concentration of 5 to 150 mg / l.
The decomposition method described. 12. The functional water has a hydrogen ion concentration (pH value).
4 to 10; a redox potential (working electrode: platinum electrode; reference electrode: silver-silver chloride electrode) of 300 to 1100 mV; and a chlorine concentration of 2 to 100 mg / l.
The decomposition method described. 13. The decomposition method according to claim 1, wherein the light is light containing light in a wavelength range of 300 to 500 nm. 14. The decomposition method according to claim 13, wherein the light is light in a wavelength range of 350 to 450 nm. 15. The light irradiation amount is 10 μW / cm 2 to 1
The decomposition method according to claim 1, wherein the power is 0 mW / cm2. 16. The light irradiation amount is 50 μW / cm 2 -5.
The decomposition method according to claim 15, wherein the power is mW / cm2. 17. The method according to claim 1, wherein the halogenated aliphatic hydrocarbon compound is a chlorinated aliphatic hydrocarbon compound. 18. The chlorinated aliphatic hydrocarbon compound is c
18. The decomposition method according to claim 17, which is at least one of is-1,2-dichloroethylene, 1,1-dichloroethylene, trans-1,2-dichloroethylene, trichloroethylene, tetrachloroethylene, dichloromethane, trichloromethane, and pentachloroethane. 19. A means for supplying functional water to a first decomposition treatment tank, a means for supplying a halogenated hydrocarbon compound to be decomposed to the first decomposition treatment tank, and In a halogenated hydrocarbon compound decomposing apparatus having a means for irradiating light, a second decomposition treatment tank provided with a photocatalyst disposed of functional water containing a decomposition product of the halogenated hydrocarbon compound decomposed in the first decomposition treatment tank An apparatus for irradiating the second decomposition tank with light. 20. A means for supplying functional water to a decomposition treatment tank provided with a photocatalyst, a means for supplying a halogenated hydrocarbon compound to be decomposed to the decomposition treatment tank, and a light source for supplying light to the first decomposition treatment tank. Apparatus for decomposing a halogenated hydrocarbon compound, comprising: