JP2003210980A - Method for regeneration treatment of adsorbent and apparatus therefor, and method for decomposing substance and apparatus therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a method for the regeneration treatment of an adsorbent generating no wastewater problem, not merely moving a substance capable of becoming a pollutant between media but capable of fundamentally subjecting the substance to decomposition treatment and an apparatus using this method, and a method for efficiently utilizing an acting substance necessary for decomposition and an apparatus using this method. <P>SOLUTION: The adsorbent having adsorbed a substance capable of being decomposed in the presence of chlorine capable of becoming a pollutant by light irradiation is heated to obtain the substance. This substance is converted to a gaseous state and air containing the gaseous substance and chlorine is formed and subsequently irradiated with light to decompose the substance. The mixed gas comprising chlorine and the gaseous substance contained in the gas after the decomposition treatment is formed and irradiated with light to decompose the substance. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for desorbing and regenerating an adsorbed material which has been adsorbed and passed through and obtained in a solvent recovery device or a deodorizing device using an adsorbent such as activated carbon, and decomposes the desorbed material.

[0002]

BACKGROUND ART Conventionally, generally used regeneration treatment of an adsorbent such as activated carbon utilizes heating by steam or the like, and trichloroethylene, which is a substance (adsorbed substance) adsorbed on the adsorbent, , 1,1-trichloroethane, tetrachloroethylene, cis-1,2-dichloroethylene and other organic solvents are desorbed from the adsorbent.

The system used for this regeneration treatment comprises an adsorption tower, a condenser and a decanter connected to the discharge side of the adsorption tower, and an aeration tank connected to the drain side of the decanter. In this system, the temperature of the condenser is set to 10 to 30 ° C., and after desorbing the adsorbed material from the adsorbent and the vapor,
A decanter was used to separate the adsorbate from water by specific gravity. Then, on the lower side, gas components and wastewater are separated in the aeration tank, and these are discharged to the outside of the system.
Complete the process.

[0004]

However, in the method using the above system, the following can be considered. 1) A part of the recovered solvent to be adsorbed may be dissolved in the waste water and further waste water treatment may be required. 2) When the material to be treated is a water-soluble solvent, it may be difficult to recover the solvent. 3) It is necessary to further treat the organic solvent after recovering the solvent with the decanter. Incineration has the risk of causing further pollution such as the generation of dioxins. 4) After the gas component and waste water are separated in the aeration tank, pollutants are discharged to the outside.

Therefore, the present invention provides a method and apparatus for regenerating an adsorbent which does not cause a problem of drainage and does not simply move an organic solvent which may be a pollutant between media, but can also fundamentally decompose it. provide.

Further, the present invention provides a method and an apparatus for efficiently utilizing an active substance required for decomposition.

[0007]

The method for regenerating an adsorbent according to the present invention comprises regenerating an adsorbent that adsorbs a substance decomposable by light irradiation in the presence of chlorine and decomposing the substance separated from the adsorbent. (A) separating the substance into a gas phase from the adsorbent on which a substance that can be decomposed by light irradiation in the presence of chlorine is adsorbed, and (b) chlorine. A step of preparing air containing, and (c)
Preparing a mixed gas containing chlorine, the substance and air from the chlorine-containing air and a substance capable of decomposing by light irradiation in the presence of chlorine, and (d) exposing the mixed gas to light in the reaction region. Irradiating to decompose a substance that can be decomposed by light irradiation in the presence of chlorine contained in the mixed gas, and (e)
The step of discharging a decomposition product generated by the decomposition of the substance by the light irradiation from the reaction region, and (f) a part or the whole of the gas discharged from the reaction region is transferred from the adsorbent to the gas phase. It is characterized by having a step of introducing into a region to be separated.

The method for separating a substance that can be decomposed by light irradiation in the presence of chlorine according to the present invention is a method of separating the substance from a gas containing a substance that can be decomposed by light irradiation in the presence of chlorine. In, an adsorption step of bringing the gas into contact with an adsorbent to adsorb the substance to the adsorbent, and a regeneration step of separating the substance from the adsorbent having adsorbed the substance,
And a decomposition step of decomposing the substance separated from the adsorbent by irradiation of light, wherein the regenerating step and the decomposing step are performed by the above-mentioned regeneration treatment method. In this method, the regenerated adsorbent can be reused in the adsorption step.

Further, the adsorbent regeneration treatment apparatus according to the present invention is configured to regenerate an adsorbent having adsorbed a substance decomposable by light irradiation in the presence of chlorine and photodecompose the substance separated from the adsorbent. (1) Separation means for separating the substance into a gas phase from an adsorbent on which a substance decomposable by light irradiation in the presence of chlorine is adsorbed,
(2) A mixed gas preparation means for preparing a mixed gas containing chlorine, the substance and air from a chlorine-containing air and a substance decomposable by light irradiation in the presence of chlorine in a reaction region, ) Light irradiation means for irradiating the mixed gas held in the reaction region with light to decompose a substance that can be decomposed by light irradiation in the presence of chlorine contained in the mixed gas,
(4) A discharge means for discharging the decomposition product generated by the decomposition of the substance by the light irradiation from the reaction region, and (5) a part or all of the gas discharged from the reaction region in the gas phase from the adsorbent. It is characterized in that it has means for introducing it into the area to be separated into.

According to the present invention, not only is the adsorbent regenerated, but the substance that is the adsorbed substance separated from the adsorbent,
That is, it is possible to further decompose a substance that can be decomposed by light irradiation in the presence of chlorine (an object to be processed in the decomposition treatment).

Further, the present invention is a method for decomposing a substance which can be decomposed by light irradiation, which comprises introducing a substance which can be decomposed by light irradiation into a reaction region and irradiating the substance with light, Discharging a gas containing a decomposition product of the substance generated in the step of discharging from the reaction region, contacting at least a part of the gas discharged from the reaction region with an acidic solution, and contacting with the acidic solution And a subsequent step of introducing a gas into the reaction region.

Further, the present invention is a decomposition apparatus for a substance which can be decomposed by light irradiation, wherein the substance which can be decomposed by light irradiation is introduced into a reaction region and the substance is irradiated with light, and the irradiation means. Means for discharging a gas containing a decomposition product of the substance generated from the reaction zone, a means for contacting at least a part of the gas discharged from the reaction zone with an acidic solution, and a means for contacting the acidic solution. Gas
And a means for introducing it into the reaction region.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION First, the operation of the adsorbent regenerating method and apparatus according to the present invention will be described.

In the present invention, the adsorbent is heated, for example, in the adsorbent tank in the separating means which is disposed in a predetermined circulation path and constitutes a part of the circulation path. By this heating, the substance that can be decomposed by light irradiation in the presence of chlorine as the substance to be adsorbed is desorbed from the adsorbent into the gas phase in the gas state. The desorbed adsorbate in the gas state is mixed with air containing chlorine in the mixed gas preparation means in the reaction tank arranged in the circulation path to form a mixed gas. When the mixed gas is irradiated with light from the light irradiation means in the reaction region, the substances to be adsorbed in the mixed gas are sequentially decomposed. The decomposition products are guided to the outside of the reaction region by the discharging means. Thus
The adsorbent is desorbed from the adsorbent, the adsorbent is regenerated, and the adsorbent from the adsorbent is decomposed. further,
The gas introduced to the outside of the reaction region contains chlorine, and this gas is introduced into the adsorbent tank.

The gas containing the substance to be adsorbed from the adsorbent heated in the adsorbent tank is mixed with the gas containing chlorine introduced to the outside of the reaction region. Therefore, it is not necessary to mix it with air containing chlorine. When the mixed gas of the gas containing the substance to be adsorbed from the adsorbent and the gas containing chlorine that has been introduced to the outside of the reaction region is irradiated with light from the light irradiation means in the reaction region, the substance to be adsorbed in the mixed gas is sequentially decomposed. To be done. This process proceeds continuously.

By heating the gas containing chlorine that is introduced to the outside of the reaction region and introducing this gas into the adsorbent tank, the adsorbent is heated to desorb the substance to be adsorbed. You may mix.

When the substance which can be decomposed by light irradiation in the presence of chlorine is a pollutant in the environment, it is possible to perform separation and removal of the pollutant by the adsorbent and complete purification by separation and decomposition from the adsorbent. it can.

The adsorbent reprocessing apparatus according to the present invention is
The chlorine contained in the chlorine-containing air is used to decompose the substance to be decomposed. The means for preparing this chlorine-containing air, whether it is integrated with the reprocessing apparatus or incorporated as a unit that constitutes the same processing system together with the reprocessing apparatus, is prepared separately from the reprocessing apparatus and is regenerated when used. It may be connected to the processing device.

Various embodiments of the present application will be described below with reference to the drawings.

[Embodiment 1] FIG. 1 shows a system configuration for separation by desorption of an adsorbed material from the adsorbent and decomposition of the separated adsorbed material in the adsorbent regeneration processing apparatus according to the present invention. Has been done. Here, as the adsorbent, activated carbon that is frequently used will be described as an example.

In this system, an activated carbon tank 2 constituting a separating means for accommodating an activated carbon 1 to be treated, a reaction tank 3 for decomposing an adsorbed substance, and a light irradiation means 4 for irradiating the inside of the reaction tank with light. And is configured. Here, in the present embodiment, the activated carbon tank 2 can be supplied with the activated carbon already adsorbed by the substance to be adsorbed. The activated carbon tank 2 is provided with a heater 5 as a means for heating the activated carbon 1.

In the activated carbon desorption system having this structure, the activated carbon 1 which has adsorbed the adsorbed substance and has passed through the adsorption is stored in a predetermined position of the activated carbon tank 2, and the heater 5 is operated to remove the activated carbon 1. While being heated, the adsorbate is desorbed from the activated carbon 1 into the gas phase to regenerate the activated carbon 1.

Further, the chlorine-containing air is added from the means 6 for supplying the chlorine-containing gas to the flow of the air containing the gaseous adsorbate generated in the regeneration step and mixed. As a result, a mixed gas of a gaseous substance to be adsorbed and chlorine is produced in the reaction region inside the reaction tank 3 where light irradiation is performed. In the reaction region, the mixed gas is irradiated with light by the lamp which is the light irradiation means 4, and the adsorbed substance is decomposed.

The processing gas containing the decomposition product and chlorine after the decomposition processing is discharged to the outside of the reaction region by the discharging means. Part or all of this exhaust gas is introduced into the activated carbon tank 2.

In the activated carbon tank 2, the substance to be adsorbed which is desorbed from the activated carbon 1 into the gas phase is mixed with the processing gas containing chlorine and the like.

Since this mixed gas contains chlorine,
It is not necessary to supply chlorine from the means 6 for supplying a gas containing chlorine.

The mixed gas carried into the reaction tank 3 is irradiated with light by the lamp which is the light irradiation means 4, and the adsorbed substance is decomposed.

By repeating this reaction continuously,
Eventually, the activated carbon, which is the adsorbent, is regenerated and the substance to be adsorbed is decomposed.

In many cases, all of the exhaust gas is supplied to the activated carbon tower 2
Since it is used for regeneration, the treated gas is not discharged from the discharge pipe 9 by the supply control valve 8 in the process of normal desorption / decomposition / regeneration. However, when the chlorine concentration in the gas after the treatment becomes extremely high, it is necessary to discharge the gas after the treatment from the exhaust pipe 9.

At this time, it is necessary to introduce a gas corresponding to the released amount from the outside of the system. (Not shown) Each part will be described in more detail below.

(Decomposition-target substance adsorbent) Any adsorbent for a decomposition-target substance that can be used in the system according to the present invention may be used, but the surface is generally in the form of a solid with a porous surface.
For example, in addition to activated carbon and activated carbon fibers made by carbonizing cellulosic substances and chitinous substances such as wood, which are commonly used for adsorption of hydrocarbon compounds, silica, zeolite, iron and alumina, etc. Examples thereof include a porous metal obtained by firing powder, activated clay that is also used as an oil desorption agent and a deodorant.

Among them, activated carbon is generally used, but has a specific surface area of 300 to 3000 m2 / g and a pore size of 3
0-3300 angstroms, TCE in gas phase
If so, it is said to adsorb about 10 times its own weight. Also,
According to the experiments conducted by the present inventors, in the case of TCE dissolved in a liquid, if approximately 400 times the TCE amount of activated carbon is added, the TCE concentration of the liquid is 0.03 which is an environmental standard due to its adsorption action.
It becomes less than mg / L.

For this reason, if the activated carbon that has just started to be used is filled with about 1 g of a TCE aqueous solution having a concentration of several mg / L at a flow rate of 10 mL / min, it can be used for several tens of hours.
It is a calculation that can keep the concentration on the outflow side below the environmental standard value. At present, various activated carbon fibers have been developed, and there is an activated carbon sheet obtained by processing these into a cloth shape or a non-woven cloth shape, or a cartridge shape.

In the present invention, the substance to be decomposed, which is the substance to be decomposed, and chlorine necessary for the decomposition coexist, so it is advisable to select a type that adsorbs the substance to be adsorbed well and has a low chlorine adsorption capacity.

(Substance to be Treated) Examples of the substance to be treated, which is a “substance that can be decomposed by light irradiation in the presence of chlorine”, include chlorinated ethylene and chlorinated methane. Specifically, as chlorinated ethylene,
Chloroethylene, dichloroethylene (DCE), trichloroethylene (TCE), tetrachloroethylene (PC
E) is mentioned. Further, as dichloroethylene, for example, 1,1-dichloroethylene (vinylidene chloride), c
is-1,2-dichloroethylene, trans-1,2
Mention may be made of dichloroethylene. Examples of the chlorinated methane include chlorine-substituted compounds of methane, such as chloromethane, dichloromethane and trichloromethane. In addition, chlorine substitution products of ethane such as 1,1,1-trichloroethane and chlorinated benzene are also included.

There is no particular limitation on the origin of the substance to be adsorbed, which is to be decomposed.
It can be applied to purification of exhaust gas, soil polluted with the above pollutants and groundwater. For example, the present invention can be used for removing and decomposing gas generated during air stripping and contaminants contained in vacuum extracted gas from contaminated soil.

(Adsorbent heating means) As the adsorbent heating means provided in the separating means, there are methods such as microwave heating, heater heating, steam pipe or steam desorption, which are determined depending on the combination with the adsorbent. In order to be heated by microwaves, it is desirable that the electric resistance be large.
Pitch-based fibrous activated carbon has an electric resistance of 150 mm layer thickness.
Has a resistance of about 3 Ω, but since the electric resistance of porous metal or PAN-based fibrous activated carbon is much smaller, another heating method such as heating with a heater, heating with warm air, or steam desorption is used. Need to take.

A heater 5 attached to the outside of the activated carbon tank 2.
Is, for example, a microwave oscillator with a frequency of 2450 MHz.
The z · 1.2 kW is usually used in a household microwave oven. The state of microwave heating is activated carbon tank 2
Far-infrared remote thermometer installed in
The surface temperature of is detected and the irradiation energy of microwave is controlled.

An example of the surface temperature is 120 ° C. In this system, since steam is not used for heating, the system is a dry system, and since the entire activated carbon tower is not heated, the energy saving effect is large and the equipment is inexpensive.

Since these heating means are directly exposed to chlorine gas, it is necessary to make them from a corrosion resistant material or to cover the outside.

(Means for Supplying Gas Containing Chlorine) As the means 6 for supplying a gas containing chlorine in the present invention, for example, a chlorine gas generating means having a structure in which a container such as a chlorine gas cylinder is filled with chlorine is used. it can. Also,
A means for contacting water containing chlorine and air to generate chlorine gas may be used. Further, it is possible to use a chlorine gas generating means for generating chlorine from the source gas by performing photolysis using the source gas. Further, a means for separating chlorine from the adsorbent on which chlorine is adsorbed into the gas phase can be used.

In any case, the chlorine gas concentration in the reaction tank 3 is 5 ppmV to 1000 ppmV, preferably 1
It is necessary to adjust the chlorine gas supply amount so as to be 0 ppmV to 500 ppmV.

During operation for decomposition, chlorine gas is supplied from the above-mentioned means for supplying gas containing chlorine to perform decomposition treatment, and thereafter, chlorine gas in the gas after decomposition treatment is supplied to decompose. Perform processing. This is because chlorine is hardly consumed by decomposition, and chlorine is generally generated from the chlorine compound that is the decomposition target, so the overall chlorine concentration tends to increase, and the gas after decomposition is used as the chlorine supply source. When used for decomposition again, chlorine concentration does not matter much.

That is, if chlorine is supplied from the means 6 for supplying a gas containing chlorine at the beginning of the decomposition operation, then the decomposition reaction can be continued without supplying chlorine from outside the system.

The chlorine gas cylinder used as the means 6 for supplying the chlorine-containing gas supplied during the operation for decomposition may be a commercially available chlorine gas cylinder used for sterilizing tap water at a water purification plant. Used for semiconductor manufacturing 99
There are some ultra high purity compounds that exceed%, but it does not have to be so high. This is also decompressed to about several atmospheres with a commercially available corrosion-resistant decompression device exclusively for chlorine gas.

Further, water containing chlorine is brought into contact with air,
For example, air containing chlorine necessary for decomposition may be generated by passing air through water containing chlorine.

As the chlorine-containing water serving as a chlorine-containing air supply source, for example, an electrolyte (eg, sodium chloride or potassium chloride) is dissolved in raw water, and this water is stored in a water tank having a pair of electrodes. Water that can be obtained near the anode by electrolysis can be used. The chlorine-containing air can also be obtained by arranging a means for introducing air into the water that can be obtained near the anode.

Water that can be obtained near the anode has a hydrogen ion concentration (pH value) of 1 or more and 4 or less, preferably 2 or more and 3 or less, and a dissolved chlorine concentration of 5 mg / L or more 20
0 mg / L or less, preferably 30 mg / L or more 120 m
Water having a property of not more than g / L is preferable.

It is also possible to obtain water containing chlorine, which serves as a supply source of air containing chlorine, by dissolving various reagents in raw water in addition to the method by electrolysis described above.

For example, using a chlorine water producing means provided with a water tank, means for supplying an aqueous solution of hypochlorite to the water tank, and means for supplying an aqueous solution containing at least one of an inorganic acid and an organic acid to the water tank. Obtainable.

The chlorine-containing water obtained by such synthesis is, for example, hydrochloric acid 0.001 mol / L to 0.1 mol / L and sodium hypochlorite 0.0001 mol / L to 0.
It can be obtained by setting it as 01 mol / L.

PH of 1.0 to 4.0 with hydrochloric acid and hypochlorite, and dissolved chlorine concentration of 2 mg / L to 2000 m
It is also possible to prepare water containing chlorine of g / L or less.

It is possible to generate chlorine necessary for decomposition from all of these waters, and by mixing this with chlorine and subjecting it to light irradiation, light irradiation is performed to decompose the adsorbed substance to be treated. It can be used in the invention.

In addition, in the structure in which photolysis is performed using the source gas to generate chlorine from the source gas, it is necessary to select a wavelength of light capable of decomposing the source gas.

The light irradiation means for generating chlorine from this source gas may be combined with the light irradiation means 4 for irradiating the photoreaction tank 3.

It is also possible to separate chlorine from the adsorbent on which chlorine is adsorbed in the gas phase to generate chlorine.

At this time, the structure in which chlorine contained in the gas discharged from the reaction region is adsorbed on the adsorbent and used, is suitable for a mode in which the activated carbon adsorption step and the regeneration step described later are repeated.

(Light Irradiating Means) As the light irradiating means which can be used in the present invention, light which does not include light of 300 nm or less, for example, light having a wavelength of 300 to 500 nm is preferable.
It is more preferable to use light of 350 to 450 nm. The light irradiation intensity is, for example, several hundreds μW / cm 2 (300 nm to 400 nm in the case of a light source having a peak around a wavelength of 360 nm).
Intensity of (measured between nm) promotes practically sufficient decomposition.

As a light source for such light, natural light (eg, sunlight) or artificial light (mercury lamp, black light, color fluorescent lamp, etc.) can be used.

In the drawings of the embodiments, the light irradiating means is rod-shaped, but of course, any shape such as dot-shaped, bulb-shaped or plane-shaped may be used.

In one embodiment of the present invention, 250
Since it is not necessary to use ultraviolet light of around nm or less, it is not necessary to install a safety device so as not to affect the human body, and it is not necessary to configure the decomposition reaction tank with quartz glass that easily transmits ultraviolet light. It is possible to reduce the cost of the device.

(Decomposition Reaction Tank) The decomposition treatment area may be physically limited in any form, but as described above, in the form in which the purification reaction proceeds with light not containing light of 300 nm or less. , It is not necessary to use expensive quartz glass or special additives that have improved UV transparency.
Ordinary glass plastic or the like that transmits visible light having a wavelength of nm or more can be used. As a result, an inexpensive system can be achieved as compared with an apparatus that needs to irradiate ultraviolet rays.

By increasing the selection of materials, the degree of freedom in selecting the form and shape of the reaction tank is increased. For example, a bag-shaped one such as an air bag can be used as the reaction tank.

(Decomposition Reaction Mechanism) The present inventors have already found that the irradiation of light in the presence of chlorine gas causes the decomposition of the organochlorine compound, but the reaction mechanism was largely unknown. However, it is already known that chlorine is dissociated to generate radicals when it receives light with a wavelength in a specific range. Also in the present invention, it is considered that chlorine radicals are generated by light irradiation and react with the substance to be decomposed to break the bond.

[Embodiment 2] In Embodiment 1 described above, an example of an apparatus adopting the present invention, which is used for adsorbing a substance to be adsorbed and regenerating an adsorbent in a state of adsorption breakthrough, is shown. However, it is also possible to configure a system that removes decomposition products in a closed loop.

Such an example is shown in FIG. In this system, the decomposition products contained in the processing gas discharged from the reaction tank are removed by the decomposition product removing means of 10.

When the original gas is an organic chlorine compound, a trap tank or the like can be used as a means for removing the decomposition products. For example, the decomposition gas can be transferred from the gas phase to the liquid phase by contacting the processing gas from the reaction tank with an aqueous solution such as water, and a gas containing no decomposition product can be discharged. By adjusting the pH of the aqueous solution to an acidic side, for example, pH of 0.5 or more and 5 or less, chlorine is hardly absorbed by the aqueous solution and is supplied to the activated carbon tank in a state of being contained in a gas containing no decomposition products discharged. To be done.

Since the decomposition products are often acidic,
The pH of the initial aqueous solution decreases with operation. Considering this, it is preferable to set the initial pH of the aqueous solution.

Further, the means for removing the decomposition products may be provided with means for decomposing the decomposition products.

The decomposition products are efficiently removed by the decomposition products removing means, so that the decomposition products do not inhibit the decomposition reaction and the decomposition products can be prevented from being adsorbed on the adsorbent. .

The above-mentioned structure is such that the decomposition products contained in the processing gas discharged from the reaction tank are removed by the decomposition product removing means, and the gas containing chlorine, which is an active substance necessary for the decomposition, is supplied to the reaction region. It can also be used for purposes other than regenerating activated carbon.

For example, when a pollutant gas generated from polluted soil or polluted groundwater contains a substance that can be decomposed by light irradiation in the presence of chlorine, it can be used for treating such polluted gas.

Examples of the present invention used as a pollutant gas will be described in Examples 5 and 6.

[Embodiment 3] In the above Embodiments 1 and 2, an example of an apparatus adopting the present invention, which is used for adsorbing a substance to be adsorbed and regenerating an adsorbent in a state of adsorption breakthrough. However, it is also possible to configure a system in which the raw gas containing the object to be treated is adsorbed, and the adsorbent removes the object to be treated, regenerates the adsorbent, and decomposes the object to be treated. is there.

That is, one of the plurality of adsorbents is in operation by removing the adsorbed material from the raw gas, and the other is regenerating the activated carbon and decomposing the object to be treated. It is a thing.

Further, the present invention can be applied to a rotor type processing apparatus in which an adsorbent alternately passes through an adsorption region for performing an adsorption process and a desorption region for performing a regeneration process. In this rotor type device, the adsorbent is installed in a ring shape, and the treatment is continuously performed by rotating around the central axis and passing through each treatment region.

By alternately performing the adsorption removal, the regeneration of the activated carbon and the decomposition of the treatment object, it is possible to continuously remove the treatment object and regenerate the activated carbon.

In such a system, the adsorbent does not necessarily have to be 100% regenerated. It suffices that the adsorption ability is restored to the extent that the object to be treated is removed again. In that sense, the decomposition in the reaction tank 3 is not perfect,
For example, the decomposition rate may be about 90%. In other words, it may be more efficient in terms of the entire system to regenerate the adsorbent by using the treated gas in which the decomposition target remains.

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

[0080]

EXAMPLES Example 1 A decomposition experiment was carried out using the processing apparatus shown in FIG.

In this experimental example, air is supplied to water containing chlorine as means 6 for supplying a gas containing chlorine to obtain air containing chlorine.

Solution containing hypochlorous acid (hydrochloric acid 0.006 m
ol / L, and sodium hypochlorite 0.002mo
1 / L, pH 2.3) was placed in a storage tank and aerated therewith, and the generated air was supplied to the reaction tank 3.

Activated carbon having adsorbed TCE and PCE gases was placed in the activated carbon tank 2 of the apparatus shown in FIG. 2 and heated by a heater, and at the same time air circulation was started. Next, the inside of the reaction tank was illuminated with a black light fluorescent lamp. This lamp is 300n
The light irradiation unit (4 in FIG. 2) is placed in a glass container that transmits light having a wavelength of m or more, and the light irradiation unit (4 in FIG. 2) is arranged to perform light irradiation from the inside. The supply control valves 7 and 8 were controlled to form a completely closed system, and an aqueous solution of which pH was adjusted to 3.0 with hydrochloric acid was used as 10 and was brought into contact with the gas after the photolysis treatment.

After operating this device for 5 hours, the activated carbon 1 was extracted with n-hexane and measured. As a result, it was found that TCE and PCE were not detected from the n-hexane and the activated carbon was regenerated.

Example 2 A decomposition experiment was carried out using the processing apparatus shown in FIG.

In Example 1, a light source having a light wavelength of 300 nm to 500 nm was used as a means for irradiating light, but in this Example, a light source having a peak at 254 nm (for example, a germicidal lamp) was used. A light irradiation unit in which a germicidal lamp was inserted in a quartz tube instead of the black light was set as the light irradiation means 4 in the photolysis reaction tank 3. Therefore, in this embodiment, the means 6 for supplying the gas containing chlorine, which is used in the first embodiment and is shown in FIG. 2, is unnecessary.

First, the supply control valves 11a, b, 12a, b
By controlling the above, a contaminating gas of 200 ppmV of tetrachloroethylene was introduced into the activated carbon 1a, and the adsorption step was performed on the activated carbon 1a. As a result, it was confirmed that the polluted gas of 200 ppmV was purified.

After the adsorption to the activated carbon 1a was sufficiently performed, the supply control valves 11a, b, 12a and b were controlled to introduce the pollutant gas into the activated carbon 1b. That is, activated carbon 1b
Adsorption process is performed for 200ppmV
It was confirmed that the polluted gas in was purified. Activated carbon 1
During the adsorption step for b, the activated carbon 1a was regenerated. The tetrachloroethylene that has been heated and adsorbed by the heater 5 a is separated into the gas phase and introduced into the reaction tank 3. Tetrachloroethylene is decomposed by the light irradiation means 4 to generate trichloroacetic acid and chlorine as main products. The processing gas containing them passes through the decomposition product removing means 10. By contacting with a hydrochloric acid solution having a pH of 3.0 in the decomposition product removing means 10, trichloroacetic acid dissolves in the solution. Chlorine is not absorbed by the aqueous solution and almost passes through the decomposition product removing means 10 and is introduced into the activated carbon tower 2a containing the activated carbon 1a.

Here, it is mixed with tetrachloroethylene separated from the activated carbon 1a, and this mixed gas is mixed in the reaction tank 3
Will be introduced in. The light irradiation of the light irradiation means 4 promotes the radicalization of chlorine, and a chain reaction occurs between the chlorine radical and tetrachloroethylene to cause decomposition. Tetrachloroethylene decomposes only by irradiation with light from a light source having a peak at 254 nm, but if chlorine is present, the decomposition is significantly promoted by the chlorine radicals.

The above process (adsorption step for activated carbon 1b. For activated carbon 1a, separation of pollutants by heat, photolysis,
When the chlorine generation and the regeneration process by decomposing pollutants using the generated chlorine were continued for a predetermined period, the activated carbon 1a was almost regenerated. Therefore, the supply control valves 11a, 11b,
By controlling 12a and 12b, it was confirmed that the adsorption process was performed on the activated carbon 1a and the regeneration process was performed on the activated carbon 1b, and then this process was repeated to enable continuous treatment.

(Example 3) A decomposition experiment was conducted using the processing apparatus shown in FIG.

In Example 2, a light source having a peak at 254 nm (for example, germicidal lamp) was used, but in this Example, a light source (black light) having a light wavelength of 300 nm to 500 nm was used as the light irradiation means 4. . Therefore, in this embodiment, the quartz tube for inserting the germicidal lamp is not necessary. Instead, means 6 for supplying a gas containing chlorine is arranged as shown in FIG.

First, the supply control valves 11a, b, 12a, b
By controlling the above, a contaminating gas of 200 ppmV of tetrachloroethylene was introduced into the activated carbon 1a, and the adsorption step was performed on the activated carbon 1a. As a result, it was confirmed that the polluted gas of 200 ppmV was purified.

After the adsorption to the activated carbon 1a was sufficiently performed, the supply control valves 11a, b, 12a and b were controlled to introduce the pollutant gas into the activated carbon 1b. That is, activated carbon 1b
Adsorption process is performed for 200ppmV
It was confirmed that the polluted gas in was purified. Activated carbon 1
During the adsorption step for b, the activated carbon 1a was regenerated.

Tetrachloroethylene that had been heated and adsorbed by the heater 5a is separated into the gas phase and introduced into the reaction tank 3. As a means 6 for supplying a gas containing chlorine, a means for holding chlorine is used. The means for holding chlorine is made of an adsorbent that adsorbs chlorine, and the adsorbed chlorine is separated from the adsorbent, passes through the activated carbon 1a, and is introduced into the reaction tank 3. Chlorine may be separated by any method, but a means such as pressure change or heating can be used. Examples of adsorbents that adsorb and retain chlorine include silica gel and zeolite.

When the mixed gas of tetrachloroethylene and chlorine is irradiated with light by the light irradiation means 4 in the reaction tank 3, the tetrachloroethylene is decomposed and trichloroacetic acid and chlorine are generated as main products. The processing gas containing them passes through the decomposition product removing means 10. By contacting with a hydrochloric acid solution having a pH of 3.0 in the decomposition product removing means 10, trichloroacetic acid dissolves in the solution. Chlorine passes through the decomposition product removing means 10 almost without being absorbed by the aqueous solution, and is supplied to the means 6 for supplying a gas containing chlorine. By adjusting the amount of chlorine initially adsorbed, the chlorine adsorbent of the means 6 for supplying a gas containing chlorine holds a certain amount of chlorine. That is, chlorine is supplied while maintaining a certain equilibrium state, and chlorine is introduced into the activated carbon tower 2a containing the activated carbon 1a.

Here, it is mixed with tetrachloroethylene separated from the activated carbon 1a, and this mixed gas is mixed in the reaction tank 3
Will be introduced in. The light irradiation of the light irradiation means 4 promotes the radicalization of chlorine, and a chain reaction occurs between the chlorine radical and tetrachloroethylene to cause decomposition.

When the above process (adsorption step for activated carbon 1b; regeneration step for activated carbon 1a) was continued for a predetermined period, activated carbon 1a was almost regenerated. Therefore, by controlling the supply control valves 11a, b, 12a, b, the adsorption process for the activated carbon 1a and the regeneration process for the activated carbon 1b were performed. That is, the chlorine retained in the chlorine adsorbent of the means 6 for supplying the gas containing chlorine was used to perform the regeneration process on the activated carbon 1b.

After that, it was confirmed that by repeating the regeneration step for activated carbon 1a, the adsorption step for activated carbon 1b, the adsorption step for activated carbon 1a, and the regeneration step for activated carbon 1b, it is possible to carry out continuous treatment.

In FIG. 4, means 6 for supplying a gas containing chlorine
Was installed in the circulation path as shown in the figure, but the amount of chlorine in contact with the adsorbent may be adjusted by providing a bypass pipe to control the amount of chlorine adsorbed and controlling the valve connected thereto.

(Embodiment 4) In Embodiment 3, means for holding chlorine is used as means 6 for supplying a gas containing chlorine. Specifically, as a means for holding chlorine, an adsorbent that adsorbs chlorine is used to absorb and desorb chlorine.

In Example 4, instead of an adsorbent that adsorbs chlorine as a means for holding chlorine, a gas containing chlorine is held in the pipe section.

Chlorine was retained in the pipe portion, and this was introduced into the activated carbon for the regeneration step to decompose it.

During the switching between the adsorption step and the regeneration step, the gas containing chlorine discharged from the reaction region was once held in the pipe, and after the switching was completed, this gas was held for decomposition in the new regeneration step. Gas was supplied to start the decomposition process.

The following experiment was conducted in the same manner as in Example 3, and it was confirmed that the substance to be decomposed and the adsorbed substance could be regenerated as in Example 3.

(Example 5) In Example 1, the pollutants derived from activated carbon in the activated carbon tower 2 were decomposed, but in this Example, instead of the activated carbon tower as shown in FIG. The pollutant gas from 13 was introduced into the reaction tank 3 via the control valve 14. 100 ppmV trichlorethylene was continuously supplied as a polluting gas. The control valves 7 and 8 were controlled so as not to be a completely closed system, and an amount of gas commensurate with the inflow amount was discharged from the discharge pipe 9 after passing through the decomposition product removing means 10. Except for this, almost the same experiment as in Example 1 was performed, and it was confirmed that the decomposition treatment of the polluted gas proceeded well.

Example 6 In Example 5, a light source having a light wavelength of 300 nm to 500 nm was used as a means for irradiating light, but in this Example, a light source having a peak at 185 nm was used. A light irradiation unit inserted in a quartz tube instead of the black light was installed in the photolysis reaction tank 3 as the light irradiation means 4. Therefore, in this embodiment, the means 6 for supplying the gas containing chlorine in FIG. 5 is not always necessary.

Except for this, almost the same experiment as in Example 5 was carried out, and it was confirmed that the decomposition treatment of the polluted gas also proceeded well in this configuration.

[0109]

EFFECT OF THE INVENTION The method and apparatus for regenerating activated carbon according to the present invention does not cause a drainage problem, and it is possible to fundamentally decompose and purify not only an organic solvent that may be a pollutant but move between media. became. Also, by reusing chlorine after the decomposition treatment, it has become possible to reduce the consumption of chlorine and also reduce the environmental load.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an activated carbon regenerating apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic view of an activated carbon regenerating apparatus according to another embodiment of the present invention.

FIG. 3 is a schematic diagram of an activated carbon regenerating apparatus according to another embodiment of the present invention.

FIG. 4 is a schematic view of an activated carbon regenerating apparatus according to another embodiment of the present invention.

FIG. 5 is a schematic view of a polluted gas decomposing apparatus according to another embodiment of the present invention.

[Explanation of symbols]

1 activated carbon 2 Activated carbon tower, activated carbon tank 3 reaction tanks 4 Light irradiation means 5 heater 6 Means for supplying gas containing chlorine 7,8 Supply control valve 9 discharge pipe 10 Decomposition product removal means 11, 12 Supply control valve 13 Contamination gas supply means 14 Control valve

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B01J 20/10 B01J 20/12 C 20/12 20/20 B D 20/20 B01D 53/34 134F 134E F Term (reference) 4D002 AA21 AB03 AC10 BA02 BA04 BA12 CA07 DA26 DA35 DA41 DA46 DA47 DA53 EA02 EA08 GA01 GB02 GB20 4G066 AA02B AA05B AA22B AA64B BA16 BA22 CA33 DA02 GA01 GA18

Claims (36)

[Claims] 1. A method for regenerating an adsorbent, which adsorbs a substance capable of decomposing by light irradiation in the presence of chlorine, comprising: (a) a step of preparing air containing chlorine; and (b) the presence of chlorine. Heating the adsorbent on which a substance that can be decomposed by light irradiation is adsorbed, and separating the substance from the adsorbent into the gas phase; and (c) air containing chlorine and the separation. A mixed gas containing chlorine, the substance and air, and (d) introducing the mixed gas into a reaction region and irradiating the mixed gas with light. Discharging a gas containing a decomposition product of the substance generated by irradiation from the reaction region, and (f) partially or entirely discharging the gas from the reaction region in the gas phase of the substance from the adsorbent. And the step of introducing into the area to be separated into A method for regenerating an adsorbent, comprising: 2. The method for regenerating an adsorbent according to claim 1, wherein the separating step is a step of heating the adsorbent. 3. The concentration of chlorine gas in the mixed gas is 5 p
The method for regenerating an adsorbent material according to claim 1, wherein the adsorption material is pmV to 1000 ppmV. 4. The concentration of chlorine gas in the mixed gas is 10
The method for regenerating an adsorbent material according to claim 2, wherein the adsorbent material is from ppmV to 500 ppmV. 5. The method for regenerating an adsorbent material according to claim 1, wherein the step (a) is performed by mixing chlorine gas supplied from a container filled with chlorine and air. 6. The method for regenerating an adsorbent material according to claim 4, wherein the container filled with chlorine is a chlorine gas cylinder. 7. The method for regenerating an adsorbent material according to claim 1, wherein the step (a) is performed by bringing air into contact with water containing chlorine. 8. The method for regenerating an adsorbent material according to claim 1, wherein the step (a) is performed by irradiating the substance separated from the adsorbent in the gas phase with light. 9. The method for regenerating an adsorbent material according to claim 7, wherein the light irradiation is the light irradiation in the step (d). 10. The method for regenerating an adsorbent material according to claim 1, wherein the step (a) is performed by separating chlorine from an adsorbent on which chlorine is adsorbed into a gas phase. 11. The method for regenerating an adsorbent material according to claim 1, wherein the chlorine adsorbs chlorine contained in a gas discharged from the reaction region. 12. The chlorine-containing air of (c), which is a gas discharged from the reaction region of (f) after performing the steps of (a) to (f), is described below. The method for regenerating an adsorbent according to claim 1, wherein the steps (f) to (f) are repeated. 13. The method according to claim 1, further comprising the step of introducing a part or all of the gas discharged from the reaction region into the region after bringing the gas into contact with the aqueous solution.
11. The method for regenerating the adsorbent according to any one of 11 to 11. 14. The method for regenerating an adsorbent according to claim 12, wherein the pH of the aqueous solution is 0.5 or more and 5 or less. 15. The irradiation light to the mixed gas is from 300 to
The reproduction processing method according to any one of claims 1 to 13, which is light including light having a wavelength in the range of 500 nm. 16. The substance capable of decomposing by irradiation with light in the presence of chlorine is trichlorethylene, 1,1,1-
Trichloroethane, tetrachloroethylene, cis-
The regeneration treatment method according to any one of claims 1 to 14, which is at least one of 1,2-dichloroethylene, 1,1-dichloroethylene (vinylidene chloride), trans-1,2-dichloroethylene, chloroform, dichloromethane and chlorobenzene. 17. The regeneration treatment method according to claim 1, wherein the adsorbent is at least one of activated carbon, activated carbon fiber, silica gel, porous metal and activated clay. 18. A method for separating a substance from a gas containing a substance capable of decomposing by light irradiation in the presence of chlorine, comprising: contacting the gas with an adsorbent to adsorb the substance to the adsorbent. An adsorption step, a regeneration step of separating the substance from the adsorbent having adsorbed the substance, and a decomposition step of decomposing the substance separated from the adsorbent by light irradiation, A method for separating a substance decomposable by light irradiation in the presence of chlorine, characterized in that the decomposing step is performed by the regeneration treatment method according to any one of claims 1 to 16. 19. The separation method according to claim 17, wherein the regenerated adsorbent is reused in the adsorption step. 20. The separation method according to claim 18, wherein the adsorption step, the regeneration step, and the decomposition step are repeatedly performed to retain the gas discharged from the reaction region generated in the decomposition step and used for the subsequent decomposition step. . 21. The separation method according to claim 19, wherein the region for holding the gas discharged from the reaction region generated in the decomposition step is inside the pipe. 22. A regeneration treatment device for an adsorbent having adsorbed a substance capable of decomposing by light irradiation in the presence of chlorine, comprising: (1) a substance decomposable by light irradiation in the presence of chlorine. Separation means for separating into a gas phase from (2) chlorine-containing air and the substance, chlorine,
A mixed gas preparation means for preparing a mixed gas containing the substance and air; (3) a reaction area for holding the mixed gas; and (4) a light irradiation means for irradiating the mixed gas held in the reaction area with light. (5) a discharge means for discharging a decomposition product generated by the decomposition of the substance from the reaction region, and (6) a part or all of the gas discharged from the reaction region, the substance being discharged from the adsorbent. And a means for introducing it into a region where it is separated into phases. 23. The adsorbent reprocessing apparatus according to claim 22, wherein the separating means is a heating device. 24. The adsorbent reprocessing apparatus according to claim 21, further comprising a chlorine-containing air adjusting means for supplying chlorine-containing air, wherein the chlorine-containing air adjusting means has a container filled with chlorine. . 25. The adsorbent material regenerating apparatus according to claim 22, wherein the container filled with chlorine is a chlorine gas cylinder. 26. A chlorine-containing air adjusting means for supplying chlorine-containing air, the chlorine-containing air adjusting means contacting the water in the water tank holding the water containing chlorine with air in the water tank. 22. The adsorbent material regeneration device according to claim 21, further comprising: an air supply means for causing the air to come into contact with the water containing chlorine, and a means for discharging the chlorine-containing air obtained by contacting the water with chlorine. 27. Means for preparing chlorine-containing air for supplying chlorine-containing air, wherein the chlorine-containing air preparation means irradiates the substance separated from the adsorbent in the gas phase with light. 22. The adsorbent material regenerating apparatus according to claim 21, further comprising: means for deriving the chlorine-containing air obtained thereby. 28. The adsorption material reclaiming apparatus according to claim 25, wherein the light irradiation means is the light irradiation means of (3). 29. The adsorption material regeneration device according to claim 21, further comprising a chlorine-containing air adjusting means for supplying chlorine-containing air, and the chlorine-containing air adjusting means has a means for holding chlorine. 30. The adsorbent material regeneration device according to claim 27, wherein the means for holding the chlorine is means for holding the chlorine contained in the gas discharged from the reaction region. 31. The adsorbent regeneration treatment apparatus according to claim 21, further comprising means for bringing a part or all of the gas discharged from the reaction region into contact with the aqueous solution in the means (5). 32. The adsorbent reprocessing apparatus according to claim 29, wherein the pH of the aqueous solution is 0.5 or more and 5 or less. 33. The separating means separates the substance from the gas by introducing a gas containing a substance capable of decomposing by light irradiation in the presence of chlorine into contact with an adsorbent to separate the substance from the gas. The regenerating apparatus according to any one of claims 21 to 30, further comprising means for obtaining adsorbed adsorbent. 34. After the adsorbent is regenerated by operating the separation means, the regenerated adsorbent is treated again by contacting a gas containing a substance that can be decomposed by light irradiation in the presence of chlorine. The adsorbent regeneration processing apparatus according to claim 31, which is controlled. 35. A method for decomposing a substance decomposable by light irradiation, comprising: introducing a substance decomposable by light irradiation into a reaction region and irradiating the substance with light; A step of discharging a gas containing a decomposition product of the substance from the reaction region, a step of contacting at least a part of the gas discharged from the reaction region with an acidic solution, and a gas after the contact with the acidic solution. And a step of introducing into the reaction region, the method for decomposing a substance. 36. A device for decomposing a substance that can be decomposed by light irradiation, wherein means for introducing a substance that can be decomposed by light irradiation into a reaction region and irradiating the substance with light, and the device generated by the irradiation. A means for discharging a gas containing a decomposition product of a substance from the reaction region, a means for contacting at least a part of the gas discharged from the reaction region with an acidic solution, and a gas after contacting with the acidic solution, A device for decomposing a substance, comprising: a means for introducing the substance into the reaction region.