KR102437966B1 - Soil purifier apparatus of persistent organic pollutants and method of purification using the same and recivering method of organic solvent contained in the same - Google Patents

Abstract

The present invention provides a purification method for purifying soil containing persistent organic pollutants by photodegrading an organic solvent, wherein the organic solvent is vaporized, the vaporized organic solvent is collected, and the collected organic solvent is used in a second In the method for recovering the organic solvent injected into the soil containing residual organic pollutants, characterized in that it further comprises the step of transferring to a reaction tank and the step of liquefying the organic solvent in the second reaction tank and collecting it into a second reaction tank it's about

Description

Soil purifier apparatus of persistent organic pollutants and method of purification using the same and recivering method of organic solvent contained in the same}

The present invention relates to an apparatus and method for purifying soil containing persistent organic pollutants, and more preferably, a soil purification apparatus containing persistent organic pollutants, including a method for recovering an organic solvent used for purification, and purification using the same It relates to a method and a method for recovering an organic solvent.

In general, persistent organic pollutants are polychlorinated biphenyls (PCBs), dioxins, organochlorine pesticides, hexachlorobenzene, and polyaromatic hydrocarbons (PAHs), etc. It means a substance that contaminates everything that exists in lipids.

Among them, polychlorinated biphenyls (PCBs) are a generic term for 209 individual compounds, so-called analogs, in which 1 to 10 chlorine atoms are bonded to two phenyl rings.

However, in the past, PCBs have been recognized as a difficult soil contaminant due to their enormous usage, reckless disposal, and persistent environmental resistance.

In addition, it is known that dioxins are produced a lot when plastic types of materials are burned, and the produced dioxins float in the air and seep into the soil with rain to contaminate them.

In order to remove these persistent organic pollutants, Korean Patent Registration No. 10-1287990 discloses a method for purifying contaminated soil that combines a thermal desorption step and a subcritical water treatment step. Although a method of purifying the soil by heating to 600° C. is disclosed, the above methods require a large amount of organic solvent in the purification process, and the used organic solvent is treated as wastewater, thereby causing another environmental pollution.

1. Republic of Korea Patent Registration No. 10-1287990 (2013. 07. 15.) 2. Republic of Korea Patent Publication No. 10-2061828 (2019. 12. 26.) 3. Japanese Patent Publication No. 4996537 (2009.11.26.) 4. Republic of Korea Patent Registration No. 10-0919924 (2009. 09. 24.)

The present invention relates to a soil purifying apparatus containing persistent organic pollutants that can be reused while extracting persistent organic pollutants using an organic solvent.

The purpose of the embodiments of the present invention is not limited to the above-mentioned purpose, and other objects not mentioned will be clearly understood by those of ordinary skill in the art to which the present invention belongs from the description below. .

According to an embodiment of the present invention, in the purification method for purifying the soil containing residual organic pollutants by photodegrading the organic solvent, the steps of vaporizing the organic solvent, collecting the vaporized organic solvent, and the collected The method may further include transferring the organic solvent to a second reaction tank and collecting the organic solvent into a second reaction tank after being liquefied in the second reaction tank.

In addition, the step of recovering the organic solvent may further include irradiating ultraviolet light to the liquefied organic solvent.

In addition, the step of vaporizing the organic solvent may have a temperature before vaporization defined as a first temperature and a temperature at which vaporization is performed defined as a second temperature, wherein the first temperature and the second temperature are Relation 1 below may be satisfied.

[Relational Expression 1]

40 ≤ T ₂ -T ₁ ≤ 80℃

(In Relation 1, T1 means the first temperature, and T2 means the second temperature)

In addition, the second temperature may be 70 to 100 ℃.

In addition, the step of liquefying the organic solvent in the second reaction tank and collecting it into the second reaction tank may have a temperature at which liquefaction is performed, which is defined as a third temperature, and the third temperature may be 5 to 30°C.

In addition, the organic solvent may be any one selected from hexane and methanol.

According to another embodiment of the present invention, a first reaction tank sealed inside and the contaminated soil is transferred, a hexane injector injecting hexane into the inside of the first reaction tank, and generating ultraviolet rays inside the first reaction tank An ultraviolet lamp, a persulfate injector for injecting persulfate into the first reaction tank, an ozone injector for injecting ozone into the first reaction tank, and an ozone recovery machine for recovering the ozone into the first reaction tank And, an inhaler for recovering and moving the hexane adsorbed to the soil, a second reactor to which the hexane recovered through the inhaler is transferred, and a temperature controller for controlling the temperature inside the first and second reactors may include.

In addition, the first reaction tank may further include a vibrating rotator at a lower portion of the first reaction tank to vibrate and rotate.

In addition, it may further include a hexane recovery group for recovering the hexane vaporized in the first reaction tank and the second reaction tank through the temperature controller.

In addition, it may further include a hexane liquefier connected to the hexane recovery group to liquefy the recovered hexane.

In addition, the first reaction tank may include a movement path through which the soil is moved provided on both lower sides, respectively, and a pressurization pump provided on the movement path to move the soil.

According to another embodiment of the present invention, transferring the contaminated soil to a first reaction tank maintained at a first temperature, injecting an organic solvent into the contaminated soil transferred to the first reaction tank, the organic solvent is injected It may include the steps of photolysis treatment by irradiating ultraviolet rays to the soil, recovering the organic solvent injected into the first reaction tank, and recovering the soil from which the organic solvent has been removed.

The present invention is economical because the time required for removal using only one device is reduced by extracting and removing multi-persistent organic pollutants using an organic solvent.

In addition, the present invention is environmentally friendly because the organic solvent is recovered and reused, thereby reducing the cost of soil purification and discharging the organic solvent to the outside.

1 is a view showing a soil purification apparatus containing persistent organic pollutants according to an embodiment of the present invention.
2 is a flowchart illustrating a method for purifying soil containing persistent organic pollutants according to an embodiment of the present invention.
3 is a flowchart for explaining the step of recovering an organic solvent according to an embodiment of the present invention.

Advantages and features of embodiments of the present invention, and methods of achieving them, will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms, and only these embodiments allow the disclosure of the present invention to be complete, and common knowledge in the technical field to which the present invention pertains It is provided to fully inform those who have the scope of the invention, and the present invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout.

In describing the embodiments of the present invention, if it is determined that a detailed description of a well-known function or configuration may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. In addition, the terms to be described later are terms defined in consideration of functions in an embodiment of the present invention, which may vary according to intentions or customs of users and operators. Therefore, the definition should be made based on the content throughout this specification.

One aspect of the present invention is a method for purifying soil containing persistent organic pollutants, and more preferably comprising: injecting an organic solvent into the contaminated soil transferred to the first reaction tank; Photolysis treatment by irradiating ultraviolet light to the soil injected with the organic solvent; and recovering the organic solvent injected into the first reaction tank.

In the present invention, the persistent organic pollutants may mean organic substances contaminating the soil, such as dioxins and polychlorinated biphenyls (PCBs), organic chlorine-based pesticides, hexachlorobenzene, and poly aromatic hydrocarbons (PAHs). have.

In the present invention, contaminated soil means soil containing the persistent organic pollutants.

In the present invention, the organic solvent means a solvent for dissolving the persistent organic pollutants by wetting the surface of the soil containing the persistent organic pollutants. Examples of the organic solvent include methanol, ethanol, isopropanol, tetrahydrofuran, N-methylpyrrolidinone, cyclohexylpyrrolidinone, N-octylpyrrolidinone, N-phenylpyrrolidinone, methyl formate, dimethyl foam Amide, dimethylsulfoxide, diethyl ether, phenoxy-2-propanol, propriophenone, ethyl lactate, ethyl acetate, ethyl benzoate, acetonitrile, acetone, ethylene glycol, propylene glycol, It may be at least one selected from the group consisting of dioxane, butyryl lactone, butylene carbonate, ethylene carbonate, propylene carbonate, dipropylene glycol, and hexane. More preferably, the organic solvent may be one selected from hexane and methanol.

Another aspect of the present invention relates to a method for recovering an organic solvent injected into soil containing persistent organic pollutants, and more preferably, the organic solvent injected into the persistent organic pollutants is recovered and reused by a fractional distillation method. This is a method of recovering organic solvents injected into soil containing organic pollutants.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a view showing a soil purification apparatus containing persistent organic pollutants according to an embodiment of the present invention.

1, the soil purification apparatus 1000 containing persistent organic pollutants includes a first reaction tank 110, an organic solvent injector 120, an ultraviolet lamp 130, a persulfate injector 140, an ozone injector ( 150), ozone recovery device 160, vibration rotator 170, second reaction tank 210, inhaler 220, temperature controller 300, organic solvent recovery device 400, organic solvent liquefier 500, etc. can do.

The first reaction tank 110 may be formed in the form of a cylinder with a sealed inside, and the contaminated soil including the moving path 111 and the moving pump 112 is transported and stored therein, and a reaction can occur therein. have.

The movement path 111 may be provided on both lower sides of the first reaction tank 110 , and may be connected to the first reaction tank 110 through a pipe with an empty interior so that the soil moves.

The pressurization pump 112 is provided on the moving path 111 to apply pressure to the soil to move the soil in the first reaction tank 110 to the moving path 111 or to remove the soil in the moving path 111 . 1 It can be moved to the inside of the reaction tank (110).

According to an embodiment, at least one pressure pump 112 may be provided, and when no pressure is applied, the soil may be prevented from moving and the state may be maintained.

The organic solvent injector 120 may be connected to the inside of the first reaction tank 110 to inject the organic solvent in a liquid phase into the contaminated soil stored in the first reaction tank 110 .

According to an embodiment, when the organic solvent and the contaminated soil come into contact, residual organic pollutants in the soil may be extracted into the organic solvent phase. In addition, the organic solvent may be mixed in an amount of 100 to 150 parts by weight based on 100 parts by weight of the contaminated soil.

The ultraviolet lamp 130 generates ultraviolet rays inside the first reaction tank 110, thereby sterilizing bacteria in the soil, and persulfate and persulfate injected from the persulfate injector 140 and the ozone injector 150, which will be described later. Ozone is activated and has the effect of increasing the efficiency.

According to an embodiment, at least one ultraviolet lamp 130 may be provided, and the efficiency may be increased by generating ultraviolet rays at a high pressure.

The persulfuric acid injector 140 injects persulfate into the interior of the first reaction tank 110, and the injected persulfate is activated by ultraviolet light from the ultraviolet lamp 130 to generate sulfate radicals of high oxidizing power. Residual organic pollutants in organic solvents can be treated.

According to an embodiment, the persulfuric acid injector 140 may inject persulfate at a predetermined concentration and cycle while the reaction occurs in the first reaction tank 110 in order to increase the decomposition power.

The ozone injector 150 injects ozone into the interior of the first reaction tank 110, ozone exists in a gaseous phase, and can increase contact with soil and organic solvents, and increases ozone's oxidizing power and activation by ultraviolet rays. Persistent organic pollutants can be treated.

According to an embodiment, the ozone injector 150 may inject ozone at a predetermined concentration and cycle while the reaction occurs in the first reaction tank 110 in order to increase the decomposition power.

After the reaction is completed and the residual organic pollutants in the soil are treated, the ozone recoverer 160 may recover ozone present in the gaseous phase inside the first reaction tank 110 .

The vibrating rotator 170 is provided with a vibrating table and a rotating table at the lower part of the first reaction tank 110 so that the first reaction tank 110 vibrates and rotates, and may be operated through a motor.

According to the embodiment, the vibrating rotator 170 vibrates and rotates the first reaction tank 110 so that the soil and the organic solvent are well mixed, and the ultraviolet rays, persulfuric acid, and ozone are mixed in the slurry in which the soil and the organic solvent are mixed together. By making the contact smoothly, a photodegradation reaction, an oxidizer decomposition reaction, a photo/oxidizer decomposition reaction, etc. of the persistent organic pollutants in the soil can be induced, thereby increasing the residual ratio of the pollutants.

The second reaction tank 210 may be formed in the form of a cylinder with a sealed interior, and the organic solvent recovered through an inhaler 220 to be described later is transported and stored, and a reaction may occur therein.

The inhaler 220 may recover the organic solvent adsorbed on the soil in the first reaction tank 110 and transfer it to the second reaction tank 210 .

According to an embodiment, the inhaler 220 may prevent the soil from being sucked through the filter, and may collect only the organic solvent in a liquid state by suction.

The temperature controller 300 may adjust the temperature inside the first reaction tank 110 and the second reaction tank 210 so that the reaction is performed smoothly.

In addition, after the reaction is completed and the residual organic pollutants in the soil are treated, by raising the temperature inside the first reaction tank 110 and the second reaction tank 210, the organic solvent is vaporized to exist in a gaseous phase. can

The organic solvent recovery unit 400 is connected to the first reaction tank 110 and the second reaction tank 210 to complete the reaction, and after the residual organic pollutants in the soil are treated, the first reaction tank ( 110) and the organic solvent present in the gas phase inside the second reaction tank 210 may be recovered.

According to an embodiment, by raising the temperature of the organic solvent through the temperature controller 300, it is vaporized to remove the organic solvent remaining in the soil existing in the first reaction tank 110, and is vaporized to exist in a gaseous phase. The organic solvent may be recovered.

The organic solvent liquefier 500 may be connected to the organic solvent recovery device 400 to liquefy the recovered organic solvent.

In addition, the organic solvent liquefier 500 is connected to the organic solvent injector 120 and transfers the liquefied organic solvent to the organic solvent injector 120 so that the organic solvent can be reused, which is efficient.

The present invention is economical by simultaneously extracting and removing residual organic pollutants using an organic solvent, thereby reducing the time required for removal using only one device.

In addition, the present invention is environmentally friendly because the organic solvent is recovered and reused, thereby reducing the cost of soil purification and discharging the organic solvent to the outside.

A soil purification apparatus containing persistent organic pollutants according to an embodiment of the present invention has been described above. Hereinafter, a method for purifying soil containing persistent organic pollutants will be described with reference to FIGS. 2 to 3 .

2 is a flowchart for explaining a method for purifying soil containing persistent organic pollutants according to an embodiment of the present invention, and FIG. 3 is a flowchart for explaining a step of recovering an organic solvent according to an embodiment of the present invention.

Referring to FIG. 2 , the method for purifying soil containing persistent organic pollutants according to an embodiment ( S1000 ) includes transferring the contaminated soil to a first reaction tank ( S100 ); injecting an organic solvent into the contaminated soil transferred to the first reaction tank (S200); photodegrading treatment by irradiating the soil into which the organic solvent is injected (S300); recovering the organic solvent injected into the first reaction tank (S400); and recovering the photolysis-treated soil (S500).

S100

In this step, the contaminated soil may be transferred to the first reaction tank through the above-described pressure pump. In this case, the contaminated soil refers to soil containing persistent organic pollutants, and more preferably refers to soil containing dioxins or PCBs.

According to an embodiment, the first reaction tank may be maintained at a first temperature, preferably 20 to 30 ℃. More preferably, it may be maintained at 23 to 27°C.

S200

In this step, the organic solvent may be injected into the contaminated soil transported in step S100. Specific information on the organic solvent is omitted since it has been described above.

According to an embodiment, the organic solvent may be mixed in an amount of 100 to 150 parts by weight based on 100 parts by weight of the contaminated soil. When the amount of the organic solvent is less than 100 parts by weight based on 100 parts by weight of the contaminated soil, it may be difficult to extract residual organic pollutants present in the soil into the organic solvent.

Conversely, when the amount of the organic solvent exceeds 150 parts by weight relative to 100 parts by weight of the contaminated soil, the organic solvent is used excessively, and UV light is excessively lost in the organic solvent during photolysis, thereby reducing the purification effect. For this reason, the organic solvent may be mixed in an amount of 100 to 150 parts by weight based on 100 parts by weight of the contaminated soil, more preferably 120 to 140 parts by weight.

According to an embodiment, the step S200 is maintained for 10 minutes or more, more preferably 10 to 60 minutes after the organic solvent is injected to extract residual organic pollutants contained in the contaminated soil into the organic solvent. have.

S300

In this step, the step of photolysis treatment by irradiating ultraviolet light to the soil injected with the organic solvent in step S200 may be further included. Specifically, by irradiating the soil into which the organic solvent is injected with ultraviolet light for 10 to 60 minutes, the residual organic pollutants extracted in the organic solvent can be decomposed.

According to an embodiment, the UV light may be UV C having a wavelength of 100 to 280 nm. If the wavelength of the ultraviolet is less than 100 nm, it becomes extreme ultraviolet and is absorbed in the atmosphere and cannot reach the organic solvent. Conversely, when the wavelength of ultraviolet light exceeds 280 nm, it becomes ultraviolet B and sterilization may be reduced. For this reason, the wavelength of the ultraviolet rays is preferably 100 to 280 nm, more preferably 150 to 230 nm.

S400

In this step, the organic solvent injected into the photolysis-treated soil in S300 is recovered. Specifically, fractional distillation may be applied as a method for recovering the organic solvent, but is not limited thereto, and any known method may be used.

Referring to FIG. 3 , the step of recovering the organic solvent (S400) includes the step of vaporizing the organic solvent (S410), the step of collecting the vaporized organic solvent (S430), and the collected organic solvent into a second reactor. It may further include the step of transferring (S450) and the step (S470) of the organic solvent being liquefied in the second reactor and collected into the second reactor.

In the step of vaporizing the organic solvent (S410), the soil purification apparatus containing the persistent organic pollutants improves the temperature of the first reaction tank from the first temperature to the second temperature through the above-described temperature controller. The organic solvent may be vaporized. The second temperature means a predetermined temperature exceeding the boiling point of the organic solvent, and more preferably, may be a predetermined temperature of 70° C. or higher.

According to an embodiment, the first temperature and the second temperature may satisfy Relational Expression 1 below.

[Relational Expression 1]

40 ≤ T ₂ -T ₁ ≤ 80℃

(In the above relation 1, T ₁ means the first temperature, T ₂ means the second temperature)

When the T ₂ -T ₁ is less than 40° C., the second temperature (T ₂ ) is too low compared to the first temperature (T ₁ ), so it is difficult for the vaporization to occur actively, and the T ₂ -T ₁ is 80 If it is exceeded, compared to the cost required to raise to the second temperature, the rate of the vaporization reaction of the organic solvent has a critical value, and thus the overall production efficiency may be reduced. For this reason, the T ₂ -T ₁ may be preferably 40 to 80°C, and more preferably 40 to 50°C.

According to an embodiment, the second temperature may be 70 to 100 ℃.

In the step (S430) of collecting the organic solvent, the organic solvent vaporized at the second temperature may be collected through the above-described inhaler.

Then, in the step of transferring the collected organic solvent to the second reaction tank (S450), the vaporized organic solvent collected in the inhaler may be transferred to the second reaction tank.

Finally, in the step ( S470 ) in which the organic solvent is liquefied in the second reactor and collected into the second reactor, the vaporized organic solvent may be liquefied and collected in the second reactor in a liquid state.

According to an embodiment, the second reaction tank may be maintained at a third temperature. The third temperature means a temperature at which the vaporized organic solvent can be liquefied again, and may preferably be 5 to 30°C.

When the third temperature is less than 5° C., moisture in the second reaction tank may freeze to prevent smooth movement of the organic solvent, and moisture may be mixed with the organic solvent by dew condensation. On the other hand, when the third temperature exceeds 30° C., the rate at which the organic solvent is liquefied may decrease, thereby reducing productivity. For this reason, the third temperature is preferably 5 to 30 °C, more preferably 10 to 25 °C.

According to an embodiment, the step of irradiating ultraviolet rays to the liquefied organic solvent after S370 may be further included. In this case, the UV light may be UV C having a wavelength of 100 to 280 nm, similar to the step of photolysis treatment by irradiating UV light to the soil injected with the organic solvent.

Through this, it is possible to remove residual organic pollutants contained in the organic solvent collected in the second reaction tank.

S500

Finally, in this step, the soil from which the organic solvent has been removed through the step S400 may be recovered.

According to an embodiment, in the method for purifying the soil containing persistent organic pollutants (S1000), persulfate and ozone are injected into any one or more of the soil into which the organic solvent is injected or the organic solvent collected in the second reaction tank. can be removed.

Hereinafter, a method for purifying a soil containing persistent organic pollutants and a soil purifying apparatus using the same according to the present invention will be described in more detail through examples. However, the following examples are only a reference for describing the present invention in detail, and the present invention is not limited thereto, and may be implemented in various forms.

Also, unless otherwise defined, all technical and scientific terms have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein is for the purpose of effectively describing particular embodiments only and is not intended to limit the invention. In addition, the unit of additives not specifically described in the specification may be weight %.

go. Optimization of organic solvent recovery conditions

In order to optimize the heating temperature and time conditions for recovering the organic solvent, Examples and Comparative Examples were configured as follows.

[Example 1]

Contaminated Soil Manufacturing

Prepare contaminated soil at a ratio of 1.57 mg of PCBs (Aroclor 1248, biphenyl tetrachloride, SUPELCO) per 1 kg of sand (WHITE QUARTZ, -50+70 MESH). Specifically, 1.57 mg of a solution of PCBs (Aroclor 1248, biphenyl tetrachloride, SUPELCO) dissolved in hexane in 1 kg of sand was injected and contaminated, and then left at room temperature for about 24 hours to evaporate all of the hexane to artificially evaporate PCBs. Contaminated soil containing

organic solvent injection

100 g of the artificially prepared contaminated soil was injected into the first reactor maintained at 25° C., and 130 g of methanol was injected into the first reactor, followed by stirring for 2 hours using a vibrating rotator.

1st reaction tank temperature rise

In order to vaporize the methanol injected into the first reaction tank, the temperature of the first reaction tank was increased to 70°C.

Organic solvent vaporization and recovery

Methanol vaporized in the first reaction tank was transferred to the second reaction tank maintained at 20° C. through an inhaler to liquefy and recover methanol.

[Example 2]

All processes were performed in the same manner as in Example 1 except that methanol was vaporized by raising the temperature to 80° C. during recovery of the organic solvent.

[Example 3]

All processes were performed in the same manner as in Example 1 except that methanol was vaporized by raising the temperature to 90° C. during recovery of the organic solvent.

[Comparative Example 1]

The first reaction tank, in which methanol and contaminated soil were mixed, was raised to 70° C. and maintained, but the organic solvent recovery step was not performed. All other processes were performed in the same manner as in Example 1.

[Comparative Example 2]

The first reaction tank, in which methanol and contaminated soil were mixed, was raised to 80° C. and maintained, but the organic solvent recovery step was not performed. All other processes were performed in the same manner as in Example 1.

[Comparative Example 3]

The first reaction tank, in which methanol and contaminated soil were mixed, was raised to 90° C. and maintained, but the organic solvent recovery step was not performed. All other processes were performed in the same manner as in Example 1.

[Example of evaluation. Measurement of PCBs concentration before and after organic solvent recovery]

In order to compare the concentration of PCBs before and after the organic solvent recovery, the PCBs contained in the methanol solutions obtained in Examples 1 to 3 and Comparative Examples 1 to 3 were analyzed using a gas chromatograph/electron capture detector (GC/ECD, Varian 450-GC). ) was used to analyze the results of the relative area analysis (peak area) of PCB allotropes. In addition, the residual ratio was calculated based on the analysis result. In this case, the residual ratio may be derived through the following relational expression (2).

[Relational Expression 2]

Residual ratio (%) = 100 x (GC ₂ / GC ₁ )

(In Relation 2, GC ₁ means the residual amount of PCBs in methanol that has not performed the organic solvent recovery step, and GC ₂ means the residual amount of PCBs in methanol that has performed the organic solvent recovery step.)

The area analysis results and residual ratios of PCBs in methanol obtained by Example 1 and Comparative Example 1 are shown in Table 1 below. In addition, the area analysis result and residual ratio of the PCB in methanol obtained by Example 2 and Comparative Example 2 are shown in Table 2 below, the area analysis result and the residual ratio of the PCB in methanol obtained by Example 3 and Comparative Example 3 are shown in the table below. 3 starts.

PCB IUPAC# number of goats Comparative Example 1 Example 1 Residual ratio (%) 18 3 1507.6 12.3 0.81 28, 31 2-3 4651.0 96.1 2.07 52 4 2676.8 46.2 1.73 44 4 2972.8 10.5 0.35 101 5 1781.3 22.5 1.26 118 5 2536.7 14.1 0.55 149 5 534.8 0.0 0.00 153 6 415.6 0.0 0.00 138 6 668.3 0.0 0.00 180 7 122.9 0.0 0.00 170 7 79.5 0.0 0.00 194 8 9.6 0.0 0.00 Sum 17957.0 201.7 1.1%

PCB homologue number number of goats Comparative Example 2 Example 2 Residual ratio (%) 18 3 1449.1 85.0 5.87 28, 31 2-3 4396.0 265.5 6.04 52 4 2738.4 176.4 6.44 44 4 3985.9 193.5 4.86 101 5 1811.9 98.0 5.41 118 5 2433.7 112.7 4.63 149 5 580.3 21.9 3.77 153 6 397.8 61.4 15.43 138 6 646.0 21.3 3.29 180 7 112.9 0.0 0.00 170 7 65.4 0.0 0.00 194 8 8.6 0.0 0.00 Sum 18626.0 1035.8 5.6%

PCB homologue number number of goats Comparative Example 3 Example 3 Residual ratio (%) 18 3 1523.7 97.1 6.37 28, 31 2-3 4671.9 233.1 4.99 52 4 2793.5 147.1 5.27 44 4 3802.3 212.5 5.59 101 5 1895.1 83.8 4.42 118 5 2596.7 102.6 3.95 149 5 615.4 29.8 4.85 153 6 430.1 63.1 14.67 138 6 686.3 19.4 2.82 180 7 119.2 0.0 0.00 170 7 76.4 0.0 0.00 194 8 25.7 0.0 0.00 Sum 19236.2 988.5 5.1%

Referring to Tables 1 to 3, it can be seen that the methanol recovered at the vaporization temperature of 70, 80 and 90° C. contains less than 6% of PCBs. This is because the vaporization temperature of the PCBs is 285 to 456 ° C, whereas the vaporization temperature of the methanol is 64 to 65 ° C. This is because it does not work and remains in the first reactor. However, the reason why the residual ratio does not have 0% in the recovered methanol is that a very small amount of PCBs is mixed with methanol and vaporized.

Specifically, when methanol was vaporized at 70° C., all PCBs having 6 or more chlorines were not included, but it can be seen that PCBs having 5 or less chlorines contained 0.35 to 2.1%. On the other hand, when methanol is vaporized at 80 to 90° C., it can be confirmed that the PCB having 6 chlorines is also included. This means that as the vaporization temperature rises, a relatively toxic PCB may be included.

However, referring to Table 4 below, it can be seen that the solvent recovery rate is 1.73 to 3.00% when the vaporization temperature is 80 to 90°C, but decreases to 0.18 to 0.22% when the vaporization temperature is 70°C. That is, when the user does not want to include a PCB having a chlorine number of 6 or more when recovering the organic solvent, the organic solvent can be vaporized at 70° C. to selectively remove the relatively toxic PCB.

division Vaporization temperature (℃) 70 80 90 methanol Solvent recovery rate
(ml/min) 0.18 to 0.22 1.73 to 2.00 2.8 to 3.2 PCBs concentration compared to initial concentration (%) 1.8 to 3.6 1.0 to 4.2 1.2 to 4.8 hexane Solvent recovery rate
(ml/min) 0.2 to 0.24 2.03 to 2.53 3.45 to 4.3 PCBs concentration compared to initial concentration (%) 0.2 to 0.5 1.3 to 3.1 2.4 to 5.6

On the other hand, if the user wants to shorten the recovery time of the organic solvent, the organic solvent may be vaporized at 80 to 90 °C. Alternatively, as described above, the organic solvent vaporized at 80 to 90° C. may reduce the concentration of PCBs in the solvent while improving the recovery time by adding a UV photolysis process.

me. Optimization of organic solvent purification conditions

In order to optimize the mixing ratio of the soil and organic solvent for purifying the soil contaminated with PCBs, Examples and Comparative Examples were configured as follows.

[Example 1]

Contaminated Soil Manufacturing

Prepare contaminated soil at a ratio of 1.57 mg of PCBs (Aroclor 1248, biphenyl tetrachloride, SUPELCO) per 1 kg of sand (WHITE QUARTZ, -50+70 MESH). Specifically, 1.57 mg of a solution of PCBs (Aroclor 1248, biphenyl tetrachloride, SUPELCO) dissolved in hexane in 1 kg of sand was injected and contaminated, and then left at room temperature for about 24 hours to evaporate all of the hexane to artificially evaporate PCBs. Contaminated soil containing

organic solvent injection

100 g of the artificially prepared contaminated soil was injected into the first reactor maintained at 25° C. (= first temperature), and 130 g of methanol was injected into the first reactor, followed by stirring for 2 hours using a vibrating rotator. .

UV irradiation step

The contaminated soil and stirred methanol were irradiated with UVC of 180 nm wavelength for 20 minutes to photolyse the PCBs extracted in the methanol.

1st reaction tank temperature rise

In order to vaporize the methanol injected into the first reaction tank, the temperature of the first reaction tank was increased to 70° C. (= second temperature).

Organic solvent vaporization and recovery

Methanol vaporized in the first reaction tank was transferred to the second reaction tank maintained at 20° C. (= third temperature) through an inhaler, and methanol was liquefied and recovered.

[Example 2]

All processes were performed in the same manner as in Example 1 except that 140 g of methanol was mixed with 100 g of contaminated soil in the step of injecting the organic solvent.

[Example 3]

All processes were performed in the same manner as in Example 1 except that 110 g of methanol was mixed with 100 g of contaminated soil in the step of injecting the organic solvent.

[Example 4]

In the step of raising the temperature of the first reaction tank, the temperature of the first reaction tank was raised to 90° C., and the methanol recovered from the second reaction tank was irradiated with UVC of 180 nm wavelength again for 60 minutes. The same was performed.

[Example 5]

All processes were performed in the same manner as in Example 4 except that 140 g of methanol was mixed with 100 g of contaminated soil in the step of injecting the organic solvent.

[Comparative Example 1]

All processes were performed in the same manner as in Example 1 except that 80 g of methanol was mixed with 100 g of contaminated soil in the step of injecting the organic solvent.

[Comparative Example 2]

All processes were performed in the same manner as in Example 1 except that 170 g of methanol was mixed with 100 g of contaminated soil in the step of injecting the organic solvent.

[Comparative Example 3]

All processes were performed in the same manner as in Example 1 except that 180 g of methanol was mixed with 100 g of contaminated soil in the step of injecting the organic solvent.

[Comparative Example 4]

All processes were performed in the same manner as in Example 4 except for the process of re-irradiating UV to the methanol recovered in the second reaction tank.

[Comparative Example 5]

All processes were performed in the same manner as in Example 5 except for the process of re-irradiating UV to the methanol recovered in the second reaction tank.

[Comparative Example 6]

All processes were performed in the same manner as in Example 1 except for maintaining the temperature of the first reaction tank at 15° C. in the organic solvent injection step.

[Comparative Example 7]

All processes were performed in the same manner as in Example 1 except for maintaining the temperature of the first reaction tank at 40° C. in the organic solvent injection step.

per 100 g of contaminated soil
Methanol mixing amount (g) first temperature (°C) Second temperature (°C) UV irradiation on recovered methanol Example 1 130 25 70 X Example 2 140 25 70 X Example 3 110 25 70 X Example 4 130 25 90 ○ Example 5 140 25 90 ○ Comparative Example 1 80 25 70 X Comparative Example 2 170 25 70 X Comparative Example 3 180 25 70 X Comparative Example 4 130 25 90 X Comparative Example 5 140 25 90 X Comparative Example 6 130 15 70 X Comparative Example 7 130 40 70 X

The concentration of PCBs remaining in the organic solvent (methanol) irradiated with ultraviolet light after mixing with the soil contaminated in Examples 1 to 5 and Comparative Examples 1 to 7 and the organic solvent (methanol) recovered in the second reaction tank was then measured. .

The PCBs were measured using a gas chromatograph/electron capture detector (GC/ECD, Varian 450-GC) in the same manner as in the previous example, and the measurement results are summarized in Table 6 below.

PCBs concentration (mg/ℓ) before UV irradiation after UV irradiation Recovered organic solvent Example 1 0.28 0.03 less than 0.01 Example 2 0.31 0.05 less than 0.01 Example 3 0.35 0.06 less than 0.01 Example 4 0.34 0.05 less than 0.01 Example 5 0.35 0.06 less than 0.01 Comparative Example 1 0.37 0.14 0.08 Comparative Example 2 0.25 0.18 0.14 Comparative Example 3 0.25 0.16 0.12 Comparative Example 4 0.31 0.05 0.01 Comparative Example 5 0.28 0.06 0.02 Comparative Example 6 0.2 0.14 0.1 Comparative Example 7 0.45 0.23 0.12

Referring to Table 6, according to the embodiment of the present invention, it can be seen that the concentration of PCBs after UV irradiation is 0.08 mg/L or less, and at this time, the concentration of PCBs in the recovered organic solvent is less than 0.01 mg/L.

On the other hand, in Comparative Example 1 (80 g), in which the methanol mixing amount per 100 g of contaminated soil is less than 100 g, and Comparative Example 2 (170 g) and Comparative Example 3 (180 g) exceeding 150 g, the concentration of PCBs after UV irradiation was 0.14, 0.18 and 0.16, respectively. As a result, it can be confirmed that it exceeds 0.08 mg/L. This is because either the residual organic pollutants are not smoothly extracted due to insufficient amount of the organic solvent mixed into the contaminated soil, or the UV is lost in the organic solvent because the organic solvent is used excessively. For this reason, if the organic solvent is not mixed in 100 to 150 parts by weight based on 100 parts by weight of the contaminated soil, it can be confirmed that the purification efficiency is reduced.

In addition, comparing Examples 4 to 5 and Comparative Examples 4 to 5, the concentration of PCBs after UV irradiation of Example 4 and Comparative Example 4 was 0.05 mg/L, and Example 5 and Comparative Example 5 were 0.06 mg/L. The organic solvent was sufficiently purified by UV photolysis.

However, it can be seen that the recovered organic solvent contained some small amount of PCBs. In particular, the organic solvents recovered in Comparative Examples 4 to 5 contained a large amount of chlorine (Cl), and thus, PCBs of #118, #149, #153, and #138, which were relatively highly toxic, were detected. On the other hand, it can be seen that in Examples 4 and 5, in which additional UV treatment was performed on the organic solvent recovered under the same experimental conditions, the PCBs concentration was less than 0.01 mg/L, as in Examples 1 to 3. This means that it is necessary to perform additional UV treatment in order to completely remove the toxicity of the organic solvent vaporized at 70° C. or higher.

Finally, Comparative Example 6 in which the temperature (first temperature) of the first reaction tank is maintained at 15°C and Comparative Example 7 in which the temperature (first temperature) of the first reaction tank is maintained at 40°C Also, the concentration of PCBs after UV irradiation is 0.08 Exceeding mg/L, the concentration of PCBs in the recovered organic solvent also exceeded 0.01 mg/L, indicating that PCBs were not sufficiently reduced compared to Examples 1 to 5. It seems that the first temperature was too low so that the PCBs were not sufficiently extracted with methanol during the mixing process (Comparative Example 6), or the UV photolysis efficiency was reduced because the PCBs were excessively extracted with methanol during the mixing process.

Accordingly, the present invention mixes the mixing ratio of the contaminated soil and the organic material by adding 100 to 150 parts by weight of an organic solvent with respect to 100 g of the contaminated soil and 100 parts by weight of the contaminated soil, and the first reaction is maintained at 20 to 30 ° C. A soil purifying device containing residual organic pollutants that creates optimal mixing conditions to remove residual organic solvents by mixing in the sub, and then recovers organic solvents by vaporizing the organic solvents at a temperature of 70 to 90°C, using the same A purification method and an organic solvent recovery method were developed.

In the above description, various embodiments of the present invention have been presented and described, but the present invention is not necessarily limited thereto. It will be readily appreciated that branch substitutions, transformations and alterations are possible.

110: first reactor 111: transfer path
112: pressurized pump 120: organic solvent injector
130: UV lamp 140: persulfate injector
150: ozone injector 160: ozone recoverer
170: vibrating rotator 210: second reaction tank
220: inhaler 300: thermostat
400: organic solvent recovery unit 500: organic solvent liquefier

Claims (13)

transferring the contaminated soil to a first reaction tank maintained at a first temperature;
injecting an organic solvent into the contaminated soil transferred to the first reaction tank;
photolysis treatment by irradiating the soil into which the organic solvent is injected;
recovering the organic solvent injected into the first reaction tank; and
Recovering the soil from which the organic solvent has been removed;
The step of photodegrading treatment by irradiating ultraviolet rays to the soil injected with the organic solvent,
vaporizing the organic solvent;
collecting the vaporized organic solvent;
transferring the collected organic solvent to a second reactor; and
liquefying the organic solvent in the second reactor and collecting the organic solvent into a second reactor;
Re-irradiating ultraviolet light to the organic solvent recovered from the second reaction tank; delete According to claim 1,
In the step of vaporizing the organic solvent, it may have a temperature before vaporization defined as a first temperature and a temperature at which vaporization is performed defined as a second temperature,
The method for recovering the organic solvent injected into the soil containing persistent organic pollutants, characterized in that the first temperature and the second temperature satisfy the following relational expression 1.
[Relational Expression 1]
40 ≤ T ₂ -T ₁ ≤ 80℃
(In the above relation 1, T ₁ means the first temperature, T ₂ means the second temperature) 4. The method of claim 3,
The method for recovering the organic solvent injected into the soil containing the persistent organic pollutants, characterized in that the second temperature is 70 to 100 ℃. The method of claim 1,
The step of liquefying the organic solvent in the second reaction tank and collecting it into the second reaction tank may have a temperature at which liquefaction is performed, which is defined as a third temperature,
The third temperature is a method of recovering an organic solvent injected into the soil containing persistent organic pollutants, characterized in that 5 to 30 ℃. The method according to any one of claims 1 to 5,
The organic solvent is a method for recovering the organic solvent injected into the soil containing residual organic pollutants, characterized in that any one selected from hexane and methanol. A first reaction tank in which the inside is sealed and the contaminated soil is transported;
an organic solvent injector for injecting an organic solvent into the first reaction tank;
an ultraviolet lamp for generating ultraviolet rays inside the first reaction tank;
a persulfuric acid injector for injecting persulfate into the first reaction tank;
an ozone injector for injecting ozone into the first reaction tank;
an ozone recovery device for recovering the ozone inside the first reaction tank;
an inhaler for recovering and moving the organic solvent adsorbed to the soil;
a second reactor to which the organic solvent recovered through the inhaler is transported;
A temperature controller for controlling the temperature inside the first reaction tank and the second reaction tank
including,
The ultraviolet lamp is subjected to photolysis treatment by irradiating ultraviolet rays to the soil into which the organic solvent is injected,
A soil purifying device containing residual organic pollutants for re-irradiating ultraviolet rays to the solvent recovered from the second reaction tank. 8. The method of claim 7,
A soil purifying apparatus containing residual organic pollutants further comprising a vibrating rotator at a lower portion of the first reaction tank to allow the first reaction tank to vibrate and rotate. 8. The method of claim 7,
The soil purification apparatus containing residual organic pollutants further comprising an organic solvent recoverer configured to recover the organic solvent vaporized in the first reaction tank and the second reaction tank through the temperature controller. 10. The method of claim 9,
A soil purifying apparatus containing residual organic pollutants further comprising an organic solvent liquefier connected to the organic solvent recovery device to liquefy the recovered organic solvent. 8. The method of claim 7,
The first reaction tank,
A movement path provided on both sides of the lower portion to move the soil,
A soil purification apparatus containing persistent organic pollutants including a pressurization pump provided on the movement path to move the soil. 12. The method according to any one of claims 7 to 11,
The organic solvent is a soil purification apparatus containing residual organic pollutants, characterized in that any one selected from hexane or methanol. transferring the contaminated soil to a first reaction tank maintained at a first temperature;
injecting an organic solvent into the contaminated soil transferred to the first reaction tank;
photolysis treatment by irradiating the soil into which the organic solvent is injected;
recovering the organic solvent injected into the first reaction tank; and
Recovering the soil from which the organic solvent has been removed;
The step of photodegrading treatment by irradiating ultraviolet rays to the soil injected with the organic solvent,
vaporizing the organic solvent;
collecting the vaporized organic solvent;
transferring the collected organic solvent to a second reactor; and
liquefying the organic solvent in the second reactor and collecting the organic solvent into a second reactor;
Re-irradiating ultraviolet rays to the solvent recovered from the second reaction tank;

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