JP2000354854A - Pollution environment purification device and restoration method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To purify underground air and groundwater containing volatile organic chlorine compounds at the existing position by bringing the volatile organic chlorine compounds into contact with a chlorine gas under light irradiation after introducing them into a chamber having a porous outer wall under reduced pressure. SOLUTION: A column-type or a plate-type purifying apparatus 100 consists of a chamber 1 provided with a porous outer walls 2, a light irradiation device 3, an inlet 5 of a chlorine gas into the chamber 1, an outlet 6, and an electric wire or an optical fiber 7. The chamber 1 is depressurized by a sucking pump connecting to the outlet 6 via a pressure proof hose, and introduces volatile organic chlorine compounds from underground air and/or groundwater containing the volatile organic compounds through the porous outer wall 2. Then, a chlorine gas is introduced from the inlet 5, and an electric power is supplied to the light irradiation device 3 via the electric wire 7, and the sun's light or artificial sun light is introduced via the optical fiber 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for purifying an environment (soil, groundwater, etc.) contaminated with a volatile organic chlorine compound.

[0002]

2. Description of the Related Art Various volatile organic chlorine compounds have been used in the development of industrial technology, and their disposal is a serious problem due to their chemical stability. In addition, environmental problems such as the use of used volatile organic chlorine compounds polluting the natural environment have occurred, and great efforts have been made to solve them. Typical volatile organic chlorine compounds are chlorinated aliphatic hydrocarbons such as trichloroethylene and tetrachloroethylene, and a technique for economically and efficiently purifying soil and groundwater leaked and contaminated by these compounds is desired.

[0003] In order to purify the soil, in addition to excavating and burning the contaminated soil, a method of vacuum-suctioning underground air or groundwater in the contaminated soil to adsorb and recover volatile organic chlorine compounds with activated carbon or the like is generally used. It is a target.

[0004] Methods for decomposing volatile organic chlorine compounds recovered from soil by vacuum suction include methods such as incineration, thermal decomposition, photolysis, oxidative decomposition, reductive decomposition, catalysis, and microbial decomposition. ing. For example, as an example using an oxidizing agent or a catalyst, a method of decomposing with ozone (JP-A-03-3829)
7), a method of irradiating ultraviolet rays in the presence of hydrogen peroxide (JP-A-63-218293), and a method of oxidative decomposition with hydrogen peroxide or iron salt (JP-A-60-261590) are known. . A method of decomposing volatile organic chlorine compounds in situ using hydrogen peroxide or hypochlorous acid as an oxidizing agent has also been disclosed (US Pat. A decomposition method combining sodium hypochlorite and ultraviolet irradiation has also been proposed (JP-A-05-269374, US Pat. No. 5,558,271). A method is also known in which a volatile organic chlorine compound is decomposed under alkaline conditions by irradiating light to a photocatalyst such as titanium oxide (JP-A-07-144137).

In addition to these methods, a method of irradiating a vaporized volatile organic chlorine compound with ultraviolet rays or a laser (Japanese Patent Laid-Open No.
43351, JP-A-06-262035), a method of performing oxidative decomposition using a platinum-based oxide (JP-A-06-31135), and a decomposition method using iron powder (JP-A-08-257570).

Several methods are known for efficiently separating or decomposing volatile pollutants in wastewater or groundwater. For example, a method of disposing a vane body made of a porous body in a pipe, bringing a liquid passing through the vane body into contact with a gas passing through the pipe, and moving volatile contaminants in the liquid to a gas (Japanese Patent Laid-Open No. 05-2005). 096144) and a method of decomposing volatile contaminants such as microorganisms by fixing them to a porous body, disposing them in a reactor and decomposing them (JP 08-024893, JP 09-266784, JP 10 -084947, U.S. Pat.
and so on. In addition, a method has been proposed in which a photocatalyst such as titanium oxide is used as a porous body, and a pollutant in groundwater is decomposed while irradiating the porous body (US Pat. No. 5,682,449). As described above, many methods for decomposing volatile organic chlorine compounds in underground air and underground water have been proposed, but from a practical viewpoint, a further low-cost and safe treatment method is desired.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above technical background, and an apparatus and a method capable of purifying ground air or groundwater containing volatile organic chlorine compounds in situ. It is intended to provide.

[0008]

As a result of repeated studies to achieve the above object, the volatile organic chlorine compound and chlorine gas are brought into contact with each other under light irradiation so that the volatile organic chlorine compound can be extremely efficiently used. The inventors have found that the compound can be decomposed, and have accomplished the present invention.

That is, an apparatus for purifying an environment containing a volatile organic chlorine compound according to one embodiment of the present invention includes: a chamber having an outer wall made of a porous material; a pressure reducing means for reducing the pressure in the chamber; Means for supplying gas; and light irradiation means for irradiating the inside of the chamber.

The method for purifying underground air or groundwater containing a volatile organic chlorine compound according to one embodiment of the present invention includes a chamber having an outer wall made of a porous material; a means for reducing the pressure in the chamber; Burying a purification device having a means for supplying chlorine gas to the chamber; and a light irradiating means for irradiating the inside of the chamber at a contaminated position; depressurizing the inside of the chamber and passing the gaseous volatile organic chlorine through the outer wall Introducing a compound into the chamber; introducing chlorine gas into the chamber; and irradiating the mixed gas of the chlorine gas and the gaseous volatile organic chlorine compound in the chamber with light to produce the volatile organic chlorine compound. And a step of decomposing.

The reason why the volatile organic chlorine compound is decomposed by irradiating the mixed gas of the volatile organic chlorine compound and chlorine gas with light as described above is not clear. However, it is well known that water generated by electrolysis of water containing an electrolyte such as sodium chloride contains hypochlorous acid, and chlorine is generated from this hypochlorous acid. It is considered that irradiation of this chlorine with light induces chlorine radicals, which act on decomposition.

Japanese Patent Application Laid-Open No. 08-281271 discloses a technique for decomposing a dye in a dyeing wastewater in an electrolytic cell by hypochlorous acid and / or hypochlorite ions generated by electrolysis. In addition, magazine "Water Treatment Technology" Vol.37, No.5 (1996)
Page 33 describes the treatment of dyeing wastewater using electrochemical reactions. However, there is no description in these patent publications or magazines suggesting that an aqueous medium containing a volatile organic chlorine compound can be decomposed. Further, there is no description about promoting a decomposition reaction by light irradiation.

[0013]

FIG. 1 is a sectional view of a purifying apparatus using chlorine. The purification device 100 on a columnar or flat plate comprises a chamber 1 having an outer wall 2 made of a porous material, light irradiating means 3, an inlet 5, an outlet 6 for chlorine gas into the chamber 1, an electric wire or an optical fiber 7. The conical cone 4 may be attached as needed, for example, when the cleaning device 1 is driven into soil. The inside of the apparatus is configured such that the inside of the chamber 1 can be depressurized by a suction pump connected to the outlet 6 via a pressure-resistant hose. When the pressure in the chamber 1 is reduced, the underground air and / or groundwater containing the volatile organic chlorine compound penetrates the outer wall 2 of the porous body, and passes through the porous body in the chamber 1 or Volatile organic chlorine compounds vaporized from the matrix are introduced. Further, chlorine gas is introduced from the inlet 5, and a gaseous volatile organic chlorine compound and chlorine gas are mixed inside the chamber. A baffle plate or the like that disturbs the flow of chlorine gas may be appropriately inserted into the apparatus to promote the mixing of the two. The volatile organic chlorine compound can be decomposed by irradiating the mixed gas with light using the light irradiating means 3, and as a result, the environment is purified.

After the decomposition, the environment 6 can be continuously purified by removing purified ground air or / and groundwater, excess chlorine and decomposition products from the outlet 6.

In the case where the light irradiation means 3 is an array in which a black light fluorescent lamp or a blue light emitting diode, which is inserted into a glass tube and subjected to a waterproof treatment, is arranged in a bar shape, an electric wire 7 is attached to the purification device, and power is supplied from the ground. Supply. When the light irradiating means 3 is a leaky optical fiber, the optical fiber 7 is attached to the purification device, and sunlight or artificial light is introduced from the ground.

Here, the volatile organic chlorine compounds mainly include chlorinated aliphatic hydrocarbons, specifically, vinyl chloride, 1,1-dichloroethylene, cis-dichloroethylene, trans-dichloroethylene, trichloroethylene, tetrachloroethylene and the like. And chlorinated methane such as chloromethane, dichloromethane and chloroform. These volatile organic chlorine compounds may be contained solely in soil or / and groundwater, or two or more compounds may coexist. The concentration of the volatile organic chlorine compound ranges from the environmental standard value to the concentration of the saturated aqueous solution for the compound for which the environmental standard value is set. For compounds for which no environmental standard value is provided, the treatment concentration ranges from a concentration at which no biological toxicity occurs to a concentration of a saturated aqueous solution.

In the decomposition treatment, the irradiation light may be 300 to 450
Light having a wavelength of nm may be used. The light irradiation intensity is, for example, 0.1 mW / cm for a light source having a peak at a wavelength of 365 nm.
² (measured between 300 nm and 400 nm) promotes decomposition, and a light intensity of 1 mW / cm ² or more is practically sufficient. As such a small light source suitable for a purification device buried underground or in a well, a black light, a color fluorescent lamp, a light emitting diode, and the like can be given. Alternatively, the light source and the purification device can be separated by installing a light source on the ground, introducing light from the light source into an optical waveguide such as an optical fiber, and guiding the light to a purification device in the ground or a well. Thus, in addition to artificial light sources such as mercury lamps and electroluminescent elements, which are somewhat disadvantageous in terms of heat generation and miniaturization, sunlight can be used if it can be used stably. In addition, if a leaky optical fiber is used as the light irradiating means, light can be emitted linearly or planarly, so that the decomposition efficiency in the purification device can be further improved.

In a volatile organic chlorine compound purifying apparatus, it is desired to treat a large amount of a compound per unit time.
A large decomposition reaction rate is required. Therefore, the concentration of the volatile organic chlorine compound in the aqueous medium may be increased by a concentration operation or the like, or the volatile organic chlorine compound may be vaporized and reacted in the gas phase. In the purifying apparatus of the present invention, since the decomposition reaction is considered to proceed mainly in the gas phase, it is preferable to increase the vaporization rate so that the vaporization of the volatile organic chlorine compound from the aqueous medium does not become reaction-limited. One of the most suitable methods is to use a porous body capable of increasing the area of the gas-liquid interface in the flow path of the aqueous medium to promote the gas-liquid contact and increase the vaporization rate. As a porous material, by permeating the environment, for example, groundwater, into the porous material, the volatile organic chlorine compound in the groundwater can be efficiently vaporized and introduced into the chamber.
Many organic or inorganic materials can be used for the porous body. For example, Teflon, polystyrene, polyethylene,
Porous materials such as polyurethane, vinyl chloride, urea resin, phenolic resin, and rubber; porous materials such as perlite, vermiculite, and foam glass; or fibers such as asbestos, rock wool, glass wool, ceramic fiber, animal and plant fibers, and carbonaceous fibers The same effect as the porous body can be exhibited by filling the material into the purification device. Further, inorganic materials such as alumina, calcium silicate, magnesium carbonate, and diatomaceous earth may be fired to form a porous body.

The air pressure inside the apparatus is always 0.5 to 0.9 lower than the underground air pressure and / or the underground water pressure by a suction pump.
Maintained at atmospheric pressure. When the pressure is reduced, the underground air or / and groundwater to be purified naturally penetrates into the inside of the device through the porous purification device outer wall. Further, supply of chlorine gas or supply and vaporization of functional water through the porous body are also promoted. It is also useful for draining liquid accumulated inside the apparatus. Considering the maintenance of the pump itself, the vacuum pump is preferably installed on the ground and connected to the device with a pressure-resistant hose. However, the vacuum pump may be buried in the soil together with the device and submerged in a well together with the device.

In addition, the underground air permeated into the apparatus and / or
In addition, by efficiently mixing groundwater with functional water or / and chlorine (including those derived from functional water and hypochlorous acid) and irradiating with light, it can be efficiently decomposed. Unless the mixture can be sufficiently mixed by natural diffusion, it is desirable to provide a means for mixing the two in the purification device. Specific examples include stirring the mixed gas with a stirring blade, and attaching a baffle plate to the gas flow path to promote mixing.

The chlorine used for the decomposition may be a commercially available chlorine gas. As a method for more safely supplying chlorine, chlorine gas may be vaporized from functional water and the chlorine gas may be used. This functional water refers to acidic water obtained on the anode side by dissolving an electrolyte such as sodium chloride or potassium chloride in water and electrolyzing the water with a pair of electrodes. Desirable properties of the functional water include a hydrogen ion concentration (pH value) of 1 to 4, a redox potential of 800 to 1500 m when the working electrode is a platinum electrode and the reference electrode is silver-silver chloride.
V, and the chlorine concentration is 5 to 150 mg / L. Further, an aqueous solution having the same properties as the functional water may be prepared chemically. For example, addition of hydrochloric acid to sodium hypochlorite has the same function as functional water.

FIG. 2 is a schematic perspective view of a purifying apparatus using functional water, and FIG. 3 is a sectional view taken along line AA of FIG. The purification device 11 on a columnar or flat plate is composed of two porous bodies 12 and 13 separated so that the functional water and the aqueous medium are not mixed, a light irradiation means 14, an inlet 16 and an outlet 17 of the functional water,
It comprises an electric wire or an optical fiber 18. Conical cone 1
5 may be attached as needed, such as when the purification device 11 is driven into soil. The inside of the apparatus is depressurized by a suction pump (not shown) connected to the outlet 17 via a pressure-resistant hose, and ground air or / and ground water containing a volatile organic chlorine compound permeates the outer wall 12 of the porous body,
A gaseous volatile organic chlorine compound is introduced into the chamber. The functional water is introduced into the porous body 13 whose surface has been processed so that liquid and gas do not leak from the inlet 16 to the outside of the apparatus, and chlorine gas is supplied into the chamber.
As a result, the volatile organic chlorine compound and the chlorine gas are mixed in the chamber. A baffle plate or the like that disturbs the flow may be inserted into the apparatus as appropriate in order to promote the mixing of the two. By irradiating the mixed gas with light using the light irradiating means 14, the volatile organic chlorine compound is decomposed and the environment is purified.

When the light irradiating means 14 is an array of rod-shaped black light fluorescent lamps or blue light emitting diodes which are inserted into a glass tube and subjected to waterproofing, an electric wire 18 is attached to the purification device, and power is supplied from the ground. Supply. When the light irradiating means 14 is a leaky optical fiber, an optical fiber 18 is attached to the purification device, and sunlight or artificial light is introduced from the ground.

FIG. 4 is a schematic diagram showing a case where the apparatus shown in FIG. 1 or 2 is actually buried in the ground. The decomposition device 25 is buried in the contaminated area 26 in the soil. At this time, the contaminated area 2
6 may be above or below the groundwater level. On the ground, a chlorine gas tank or a functional water generator or a functional water tank 21
Is installed, and is sent to the purification device 25 via the chlorine gas supplied therefrom or the water / air supply pipe 24. Further, the pressure inside the apparatus is reduced by using the suction pump 22 to reduce the underground air or /
And permeate the groundwater into the purifier, and collect excess chlorine, functional water, purified ground air and / or groundwater. In FIG. 3, the suction pump 22 is installed on the ground.
A structure may be used in which the air is exhausted to the ground via the. FIG.
In the above, the sunlight is collected by the light condensing device 23 and the light is introduced into the purification device by an optical fiber provided in the water supply / air supply tube 24. The lamp may be turned on.

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.
They do not limit the invention in any way.

Example 1 Contaminated groundwater was supplied by supplying chlorine gas and irradiating it with black light.
Example of Purification <Explanation of Apparatus Used in Experiment> An experimental apparatus shown in FIG. 1 was prepared and used in Examples. First, an alumina porous cylindrical tube 2 (inner diameter 40 mm, outer diameter 60 mm, length 500 mm, manufactured by NGK Insulators, FA-2) having a stainless steel conical cone 4 attached to the lower end is prepared. Prepared. Next, a light source 3 (black light, Toshiba Lighting & Technology Corp.) is placed inside the porous cylindrical tube 2.
2 W, 6 W). Finally, the upper end of the porous cylindrical tube 2 was closed with a stainless steel flange having an inlet 5 and an outlet 6 to assemble a purification device.

<Decomposition of Volatile Organic Chlorine Compounds> Pure water is placed in a sealable metal container, and 1,1-dichloroethylene,
cis-dichloroethylene, trans-dichloroethylene, trichloroethylene, tetrachloroethylene, and dissolved so that each concentration of dichloromethane becomes 5 mg / L,
Simulated contaminated groundwater.

In this water tank, a purifying device 1 connected to a Teflon tube for an inlet and an outlet and an electric wire was sunk so that the cone was directed downward. Chlorine concentration is 500 ppmV
Then, chlorine (supplied from a chlorine cylinder) and air were mixed in such a manner as to be introduced, and this was introduced from the inlet 5 at a flow rate of 10 mL / min. Further, a suction pump was attached to the Teflon tube connected to the outlet 6, and water and gas in the apparatus were sucked at a flow rate of 15 mL / min, and the light source 4 was turned on. At this time, the pressure on the suction side of the suction pump connected to the outlet 6 is about 0.8.
Atmospheric pressure. The concentration of volatile organochlorine compounds in the gas and water discharged from the suction pump was determined by gas chromatography with an electron capture detector (inject the sample directly, and inject the sample after extracting with n-hexane, Shimadzu Corporation) (GC-14B). As a result, the concentration of any volatile organic chlorine compounds in the gas was 0.05 ppmV or less. In addition, the concentration of any volatile organic chlorine compounds in the solution was 0.1 mg / L or less, and it was confirmed that the groundwater of contaminated soil could be efficiently purified by this purification device.

Next, the chlorine concentration was changed in the range of 5 ppmV to 1000 ppmV, and the concentration of the volatile organic chlorine compound after the decomposition was measured. (5 mg / L), and it was confirmed that purification was possible with this purification device.

Comparative Example 1 Example 1 was repeated except that only air was introduced from the inlet 5.
An experiment was performed in the same manner as described above. As a result, the concentration of any volatile organic chlorine compound in the gas was 100 ppmV or more, and the concentration of any volatile organic chlorine compound in the solution was 3 mg / L or more. From this, it was found that the ground air in the contaminated soil could not be purified without introducing chlorine.

Example 2 Example of Purifying Contaminated Groundwater by Irradiating Sunlight The light irradiating means 3 shown in FIG. 1 is changed to a leaky optical fiber (Sumitomo 3M, 3M light fiber sidelight high-brightness type), and sunlight is applied to the apparatus. The same experiment as in Example 1 was performed except that the irradiation was performed inside. As a result, the concentration of any chlorinated aliphatic hydrocarbon in the gas was 0.1 ppmV or less. In addition, the concentration of any chlorinated aliphatic hydrocarbon in the solution was 0.1 mg / L or less, and it was found that the chlorinated aliphatic hydrocarbon could be efficiently decomposed by this purifier.

Next, the concentration of the volatile organic chlorine compound after decomposition was measured while changing the irradiation light intensity from the leaky optical fiber in the range of 10 μW / cm ² to 10 mW / cm ^2. Initial concentration of volatile organic chlorine compounds
(5 mg / L), confirming that the groundwater of contaminated soil can be efficiently purified by this purification device.

Example 3 Contaminated groundwater was purified with a device made of Teflon porous tubes.
Example In Example 1, a porous tube made of Teflon (Teflon filter, average pore size 25) was used instead of the porous tube made of alumina.
(μm, 0.13 mm thick). Using this apparatus, the decomposition of volatile organic chlorine compounds was carried out in the same manner as in Example 1. As a result, the concentration of any volatile organic chlorine compounds in the gas was 0.7 ppmV or less. In addition, the concentration of any volatile organic chlorine compounds in the solution was set to 0.
It was 15 mg / L or less, and it was confirmed that the groundwater of contaminated soil can be efficiently purified by this purification device.

Example 4 A contaminated underground air was supplied by supplying chlorine gas and irradiating black light.
Example of Purified Air The soil was put in a metal container that can be sealed, and the same purification device as in Example 1 in which the Teflon tubes and the electric wires of the inlet and outlet were connected was buried. Next, 1,1-dichloroethylene, cis-dichloroethylene, trans-dichloroethylene, trichloroethylene, tetrachloroethylene, and dichloromethane were added, and the air in the soil was circulated and homogenized for several days to be regarded as a contaminated soil. At this time, each concentration was 10 ppmV.

The same experiment as in Example 1 was carried out, and the concentration of gas recovered from the exhaust of the suction pump was measured. The concentration of any chlorinated aliphatic hydrocarbon was 0.1 ppmV or less.
It has been confirmed that this purification device can efficiently purify underground air in contaminated soil.

Example 5 Contaminated groundwater was supplied by supplying functional water and irradiating it with black light.
Example of Purification <Explanation of Apparatus Used in Experiment> An experimental apparatus shown in FIG. 2 was prepared and used in Examples. First, an alumina porous cylindrical tube (inner diameter 40 mm, outer diameter 60 mm, length 500 mm, manufactured by NGK Insulators, Ltd., FA-2) was vertically divided into two equal parts (12 and 13), and 1
Aluminum was deposited only on the outer part of No. 3 so that the flowing solution did not leak out. Next, a stainless steel plate (width 10 mm, length 500 mm, thickness 2 mm) was sandwiched between the cross sections of both cylinders, and the cylinders were formed again. A light source 14 similar to that of Example 1 was installed inside the cylinder, and both ends of the cylinder were closed with a stainless steel flange having an inlet 16 and an outlet 17 and a conical cone, thereby producing a purification device.

<Decomposition of Chlorinated Aliphatic Hydrocarbons>
In the same way as above, the concentration of volatile
Submerged in g / L aquarium.

Next, functional water was prepared using a strongly acidic functional water generator (trade name: Strong electrolyzed water generator (Model FW-200), manufactured by Amano Corporation). Using this device, the electrolyte concentration and electrolysis time of the water to be electrolyzed are varied, and the pH and oxidation-reduction potential of the functional water obtained on the anode side are measured with a pH meter (Toko Chemical Laboratory, TCX-90i and KP900-2N) and conductivity meter (Toko Chemical Laboratory Co., Ltd., TCX-90i and K
M900-2N), and the chlorine concentration was further measured with a chlorine test paper (Advantech). As a result, the pH of this functional water is 1-4, the oxidation-reduction potential is 800-1500mV, and the chlorine concentration is 5 depending on the concentration of sodium chloride as electrolyte (standard concentration is 1000mg / L), electrolysis current value and electrolysis time. Changed to 150150 mg / L. Therefore, in this example, functional water having a pH of 2.6, an oxidation-reduction potential of 1000 mV, and a chlorine concentration of 54 mg / L was prepared as functional water. This functional water was obtained by setting the electrolyte (sodium chloride) concentration to 1000 mg / L and the electrolysis time to 5 minutes. This functional water was introduced from the inlet 16 at a flow rate of 10 mL / min. In addition, a suction pump was attached to the Teflon tube connected to the outlet 17, and at a flow rate of 15 mL per minute,
Water and gas in the device were sucked, and the light source 14 was turned on.
At this time, the pressure on the suction side of the suction pump connected to the outlet 6 was about 0.8 atm. The concentration of volatile organochlorine compounds in the gas and water discharged from the suction pump was determined by gas chromatography with an electron capture detector (injecting the sample directly and injecting the sample after extracting with n-hexane, Shimadzu Corporation) (GC-14B).
As a result, the concentration of any volatile organic chlorine compounds in the gas was 0.05 ppmV or less. In addition, the concentration of any volatile organic chlorine compound in the solution was 0.1 mg / L or less, and it was found that the volatile organic chlorine compound can be efficiently decomposed by this purifying device.

Next, when the concentration of the volatile organic chlorine compound after decomposition was measured while changing the chlorine concentration in the range of 5 ppmV to 1000 ppmV, the initial concentration of the volatile organic chlorine compound (5 mg / L)
It was confirmed that this purification device can efficiently purify groundwater in contaminated soil.

Example 6 Example of Purifying Contaminated Groundwater by Supplying Synthetic Functional Water Example 5 was prepared in the same manner as in Example 5 except that a synthetic functional water prepared with a hydrochloric acid (10 mM) solution containing 0.01% by weight of sodium hypochlorite was used. A similar experiment was performed. As a result, the concentration of any volatile organic chlorine compound in the gas was 0.05 ppmV or less, and it was found that the volatile organic chlorine compound can be efficiently decomposed by this purification device.

Further, the concentration of hypochlorite and the concentration of hydrochloric acid were changed to prepare functional water having a pH of 1 to 4, an oxidation-reduction potential of 800 mV to 1500 mV, and a chlorine concentration of 5 mg / L to 150 mg / L, and subjected to decomposition. However, in each case, the concentration was lower than the initial concentration of the volatile organic chlorine compound (5 mg / L), and it was confirmed that the groundwater of the contaminated soil could be efficiently purified by this purification device.

Example 7 Example of Purifying Contaminated Soil by Supplying Functional Water An apparatus similar to that in Example 5 was buried in the same contaminated soil as in Example 4, and an experiment was performed. As a result, the concentration of each chlorinated aliphatic hydrocarbon was 0.1 ppmV or less, and it was confirmed that the underground air of the contaminated soil could be efficiently purified by this purification device.

[0044]

According to the present invention, a volatile organic chlorine compound,
In particular, it has become possible to efficiently decompose and purify soil ground air and / or ground water contaminated with chlorinated aliphatic hydrocarbons such as tetrachloroethylene and trichloroethylene.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a purification device according to an embodiment of the present invention.

FIG. 2 is a schematic sectional view of a purification device according to another embodiment of the present invention.

FIG. 3 is a sectional view taken along line AA of FIG. 2;

FIG. 4 is a schematic diagram showing a case where the device of FIG. 1 or 2 is buried in a position to be purified;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Purifier 2 Porous body 3 Light irradiation means 4 Conical cone for underground driving 5 Inlet 6 Outlet 7 Electric wire or optical fiber for introducing light 11 Purifier 12 Porous body for infiltration of ground air or / and groundwater 13 Function Porous body for water intrusion 14 Light irradiation means 15 Conical cone for underground driving 16 Inlet 17 Outlet 18 Electric wire or optical fiber for light introduction 21 Chlorine gas tank or functional water generator or functional water tank 22 Suction pump 23 Gathering Optical device 24 Water supply air pipe with optical fiber 26 Soil contaminated area 100 Purification device

Continued on the front page (72) Kinya Kato, Inventor, 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Masahiro Kawaguchi 3-30-2, Shimomaruko, Ota-ku, Tokyo Canon Inc. F-term (reference) 4D004 AA41 AB06 AB07 CA34 CA43 CA50 CB01 CB42 CB43 CB50 CC01 CC03 CC11 CC12 CC15 DA03 DA07 DA20 4D037 AA01 AB14 BA16 BA18 BB07 BB09 4D050 AA01 AA20 AB19 BB05 BB06 BC09 BC10 A02 BD03 A03 BD05 A03 CA32 CA33 CA57 CA73 EB32 FA02 FA14 FB04 FB12

Claims (26)

[Claims] 1. An apparatus for purifying an environment containing a volatile organic chlorine compound, comprising: a chamber having an outer wall made of a porous material; means for reducing the pressure in the chamber; means for supplying chlorine gas into the chamber; And a light irradiation means for irradiating the inside of the chamber. 2. The purification device according to claim 1, wherein the porous body is a ceramic. 3. The purification device according to claim 2, wherein the ceramic is alumina. 4. The purifying apparatus according to claim 1, wherein the porous body is a polymer. 5. The purifying apparatus according to claim 4, wherein the polymer is Teflon. 6. The purification device according to claim 1, wherein the volatile organic chlorine compound is a chlorinated aliphatic hydrocarbon. 7. The chlorinated aliphatic hydrocarbon is at least one of 1,1-dichloroethylene, cis-dichloroethylene, trans-dichloroethylene, trichloroethylene, tetrachloroethylene, and dichloromethane.
Purification device according to claim 1. 8. The purification device according to claim 1, wherein the light irradiation means is at least one of an optical fiber, a mercury lamp, a black light, a light emitting diode, and an electroluminescent element. 9. The purification device according to claim 8, wherein the light source for supplying light to the optical fiber is at least one of sunlight, a mercury lamp, a black light, a light emitting diode, and an electroluminescent element. . 10. The purification device according to claim 1, wherein the wavelength of the light is in a wavelength range of 300 nm to 450 nm. 11. The light intensity of the light is 10 μW / cm ² to 10 mW / cm ^2.
The purification device according to claim 1, wherein 12. The purifying apparatus according to claim 1, wherein the means for supplying the chlorine gas includes a means for introducing functional water into the chamber. 13. The purification apparatus according to claim 1, wherein the means for supplying the chlorine gas includes a means for introducing functional water into the porous body. 14. The functional water has a hydrogen ion concentration (pH value).
14. The method according to claim 13, which has a characteristic in which the oxidation-reduction potential (working electrode: platinum electrode, reference electrode: silver-silver chloride electrode) is 800 mV to 1500 mV, and the chlorine concentration is 5 mg / L to 1000 mg / L. Purification device. 15. The purification apparatus according to claim 13, wherein the functional water is acidic water generated near the anode by electrolysis of water containing an electrolyte. 16. The purification apparatus according to claim 15, wherein the electrolyte is at least one of sodium chloride and potassium chloride. 17. The purification apparatus according to claim 13, wherein the functional water is an aqueous solution of hypochlorite. 18. The purification device according to claim 17, wherein the hypochlorite is at least one of sodium hypochlorite and potassium hypochlorite. 19. The purification device according to claim 17, wherein the aqueous solution further contains an inorganic acid or an organic acid. 20. The inorganic acid or the organic acid is at least one selected from hydrochloric acid, hydrofluoric acid, oxalic acid, sulfuric acid, phosphoric acid, boric acid, acetic acid, formic acid, malic acid and citric acid. Purification device according to claim 1. 21. The purification apparatus according to claim 1, wherein the environment is underground air or groundwater. 22. A method for purifying underground air or groundwater containing a volatile organic chlorine compound, comprising: a chamber having an outer wall made of a porous material; a means for reducing the pressure in the chamber; and supplying chlorine gas into the chamber. Burying a purification device having a light irradiation means for irradiating the inside of the chamber at a contaminated position; depressurizing the inside of the chamber and introducing the gaseous volatile organic chlorine compound through the outer wall into the chamber. Introducing a chlorine gas into the chamber; and irradiating the mixed gas of the chlorine gas and the gaseous volatile organic chlorine compound in the chamber with light to decompose the volatile organic chlorine compound. Purification method characterized by having. 23. The method according to claim 22, wherein the volatile organic chlorine compound is a chlorinated aliphatic hydrocarbon. 24. The chlorinated aliphatic hydrocarbon is 1,1-dichloroethylene, cis-dichloroethylene, trans-dichloroethylene, trichloroethylene, tetrachloroethylene,
24. The purification method according to claim 23, wherein the purification method is at least one of: and dichloromethane. 25. The purification method according to claim 22, wherein the pressure in the apparatus is reduced to 0.5 to 0.9 atm. 26. The purification method according to claim 22, wherein functional water is introduced into the porous body, and the chlorine gas is generated from the porous body.