CN115851275A - Remediation composition for polycyclic aromatic hydrocarbon contaminated soil and its application - Google Patents

Abstract

The invention proposes a remediation composition for polycyclic aromatic hydrocarbon-contaminated soil and an application thereof. The remediation composition includes persulfate, peroxide, free radical initiator and cosolvent. By adding initiator and co-solvent to the double oxidant system including peroxide and persulfate, not only can avoid the use of catalyst and chelating agent, but also improve the degradation rate of polycyclic aromatic hydrocarbons in soil. It is believed that the addition of co-solvent is beneficial to the desorption of pollutants, and the addition of initiator can stimulate persulfate and calcium peroxide to generate active free radicals, and the generated SO ₄ ^‑ and OH are mutually excited and work together to achieve repair The purpose of organic matter to pollute the soil.

Description

Remediation composition for polycyclic aromatic hydrocarbon contaminated soil and its application

technical field

The invention belongs to the technical field of remediation of organic polluted soil, in particular to a remediation composition for polycyclic aromatic hydrocarbon contaminated soil and its application.

Background technique

Organic pollutants and their hazards to human health and ecosystems are becoming more and more recognized. Countries such as the United States, the United Kingdom, Germany, and the Netherlands have placed soil pollution control on the same level as air and water pollution, and have formulated relevant restoration project plans from the perspective of the government. Germany invested about US$6 billion in soil purification as early as 1995, and the United States invested tens of billions to hundreds of billions of US dollars in soil restoration in the 1990s. But at present, our country does not pay much attention to the seriousness of soil pollution and the urgency of the treatment work. In addition, due to the characteristics of regional differences in soil, the complexity of ecosystems, and the immobility of soil, soil pollution is more complicated and difficult to control than water pollution or air pollution. Therefore, it is urgent to develop a soil remediation technology with high degradation efficiency and economical feasibility for refractory organic pollutants.

At present, there are many reports abroad about the degradation of organic pollutants in soil by single oxidants, such as peroxide, persulfate, permanganate, etc., which can achieve slow release of free radicals, high degradation efficiency, and long action time. And it has a good degradation effect on different organic pollutants. Among them, persulfate has attracted wide attention due to its advantages such as wide pH range, environmental friendliness, and long transmission distance underground. Due to its own limitations, the single oxidant system has limited ability to remove refractory pollutants, and the mixture of hydrogen peroxide and sodium persulfate may have stronger oxidizing ability. There are few reports on double oxidants, and the reported ones are mainly hydrogen peroxide and persulfate double oxidant systems. Although they have a good degradation effect on organic pollutants, they face certain difficulties in practical application, such as hydrogen peroxide The storage and transportation of organic matter and the release rate of hydrogen peroxide are too fast when the organic matter is degraded, and the effective time is short.

According to reports, calcium peroxide is a multifunctional and safe solid inorganic peroxide, which can slowly release hydrogen peroxide and generate OH in a humid environment. It is considered to be solid hydrogen peroxide and can be well used in in the process of environmental restoration. The dual oxidant system composed of persulfate and calcium peroxide has low sensitivity to environmental changes. It can not only have high oxidation activity for various organic pollutants, but also use the synergistic effect between the two oxidants to promote the degradation of refractory organic pollutants. Oxidation of pollutants, thereby improving the degradation efficiency, and providing support for the development of organic-contaminated soil remediation technology.

Polycyclic aromatic hydrocarbons are a class of refractory soil organic pollutants, which are carcinogenic, teratogenic, and mutagenic. The PAH-contaminated soil remediation agents used in the prior art include oxidizing agents, catalysts and chelating agents. The oxidizing agents are mainly peroxides and persulfates, the catalysts are mainly ferrous salts, and the chelating agents include citric acid and EDTA. Regardless of using a single oxidant or a dual-oxidant system composed of different oxidants, the remediation of polycyclic aromatic hydrocarbons in soil has problems such as low degradation efficiency and toxic and harmful degradation products, and the addition of catalysts and chelating agents increases the cost of remediation, which is not conducive to practical Use of contaminated sites.

It can be seen that it is necessary to improve the existing oxidant system for the remediation of organic matter-contaminated soil, and develop a remediation method for petroleum hydrocarbon-contaminated soil with high remediation efficiency, low remediation cost, and environmental friendliness.

Contents of the invention

In view of this, the purpose of the present invention is to overcome the problem of low degradation rate of polycyclic aromatic hydrocarbons and high repair cost in soil existing in the prior art, and provide a repair composition and application thereof for polycyclic aromatic hydrocarbon-contaminated soils. The remediation composition can increase the degradation rate of polycyclic aromatic hydrocarbons in polluted soil.

The purpose of the present invention is achieved through the following technical solutions.

In a first aspect, the present invention provides a remediation composition for PAH-contaminated soil, wherein the remediation composition includes persulfate, peroxide, free radical initiator and co-solvent.

In the present invention, by adding initiator and co-solvent to the double oxidant system including peroxide and persulfate, not only can avoid the use of catalyst and chelating agent, but also improve the degradation rate of polycyclic aromatic hydrocarbons in soil. Without wishing to be limited by theory, it is believed that the addition of co-solvent is beneficial to the desorption of pollutants, and the addition of initiator can stimulate persulfate and calcium peroxide to generate active free radicals, and the generated SO ₄ · ^- and ·OH excite each other, Work together to achieve the purpose of repairing organic matter-contaminated soil.

According to the restoration composition provided by the present invention, wherein, the restoration composition does not include a catalyst and/or a chelating agent.

According to the restoration composition provided by the present invention, the peroxide is a solid inorganic peroxide. In some embodiments, the peroxide is calcium peroxide and/or magnesium peroxide.

According to the restoration composition provided by the present invention, the persulfate is at least one selected from sodium persulfate, potassium persulfate and ammonium persulfate. In some embodiments, the persulfate is sodium and/or potassium persulfate.

According to the restoration composition provided by the present invention, the mass ratio of the peroxide to the persulfate is 1:2-8; in some embodiments, it is 1:3-6.

According to the restoration composition provided by the present invention, the free radical initiator is a water-soluble azo initiator. Examples of water-soluble azo initiators suitable for use in the present invention include, but are not limited to: azobisisobutylamidine hydrochloride, azobisisobutylimidazoline hydrochloride, azobisisobutylimidazoline sulfate salt, azobiscyanovaleric acid and azobisisopropylimidazoline.

According to the restoration composition provided by the present invention, the ratio of the mass of the peroxide and the persulfate to the mass of the free radical initiator can be 1:0.002-0.01, preferably 1:0.005-0.01 , more preferably 1:0.005 to 0.008.

According to the restoration composition provided by the present invention, the co-solvent is a monohydric or dihydric alcohol with 1 to 6 carbon atoms, preferably a monohydric or dihydric alcohol with 2 to 4 carbon atoms. Examples of co-solvents suitable for use in the present invention include, but are not limited to: ethanol, n-propanol, isopropanol, n-butanol, isobutanol, ethylene glycol, 1,3-propanediol, and 1,4-butanediol . In some embodiments, the co-solvent is ethanol and/or isopropanol.

According to the restoration composition provided by the present invention, relative to 100 g of the peroxide and the persulfate, the amount of the co-solvent is 50-200 ml, preferably 100-150 ml.

In the second aspect, the present invention provides the application of the remediation composition in remediation of polycyclic aromatic hydrocarbon-contaminated soil.

According to the application provided by the present invention, the polycyclic aromatic hydrocarbons refer to aromatic hydrocarbons containing two or more benzene rings. The content of PAHs in PAH-contaminated soils is usually greater than the screening value for soil pollution risks of various PAHs in the second type of construction land stipulated in the "Soil Environmental Quality Construction Land Soil Pollution Risk Control Standard (Trial)". For example, the polycyclic aromatic hydrocarbon is at least one selected from naphthalene, phenanthrene, anthracene, pyrene, benzo[a]pyrene and/or benzo[b]fluoranthene.

In the present invention, there is no special requirement on the size of the PAH-contaminated soil to be repaired. Generally, the smaller the soil particle size, the better the contact, which in turn facilitates remediation. However, reducing soil particle size generally increases treatment costs. In some embodiments, the particle size of the PAH-contaminated soil is below 2 mm.

According to the application provided by the present invention, the application includes the following steps:

S100, adding the first part of water and co-solvent to the PAH-contaminated soil, and mixing to obtain the first mixture;

S200, mixing the initiator, the persulfate and the second part of water and then heating to obtain a second solution;

S300. Mix the peroxide, the first mixture obtained in step S100, and the second solution in step S200.

According to the application provided by the present invention, wherein, in step S100, the amount of the co-solvent is 20-80ml, preferably 40-60ml, for example, 50ml per kilogram of the polycyclic aromatic hydrocarbon-contaminated soil; and/or, For every kilogram of the polycyclic aromatic hydrocarbon-contaminated soil, the amount of the first part of water is 3kg-5kg.

According to the application provided by the present invention, the mixing time in step S100 is 1 to 3 hours, for example, 2 hours.

According to the application provided by the present invention, wherein, in step S200, relative to each kilogram of the polycyclic aromatic hydrocarbon-contaminated soil, the dosage of the persulfate is 5g-20g.

According to the application provided by the present invention, wherein, in step S200, based on 1000 parts by weight of the peroxide and the persulfate, the addition amount of the initiator is 5-8 parts by weight.

According to the application provided by the present invention, wherein, the mass ratio of the initiator to the second part of water is 1:500-1500, preferably 1:800-1200, more preferably 1:900-1100.

According to the application provided by the present invention, the heating temperature in step S200 is 50°C-65°C. At such a temperature, it is beneficial for the initiator to excite the persulfate to generate active free radicals.

According to the application provided by the present invention, the time for the mixing treatment in step S300 is 1-12 hours, preferably 6-10 hours; and/or the mixing treatment is performed at normal temperature.

According to the application provided by the present invention, step S300 further includes: performing solid-liquid separation after the mixing treatment. In the present invention, any method known in the art can be used for solid-liquid separation, and the present invention is not special about it.

The above-mentioned raw materials in the present invention can be self-made or commercially available, which is not particularly limited in the present invention.

Compared with the prior art, the present invention has at least the following advantages:

(1) In the restoration composition of the present invention, by adding a small amount of initiator, the use of catalyst and chelating agent can be avoided, and the decomposition product of the initiator is non-toxic, which can reduce the cost of restoration, and avoid the occurrence of catalyst and chelating agent on the soil structure after restoration. Influence.

(2) The restoration method (application) provided by the present invention has a good restoration effect. The addition of co-solvent is beneficial to the desorption of pollutants, thereby improving the degradation efficiency. After remediation of high-concentration polycyclic aromatic hydrocarbon-contaminated soil by this method, the removal rate of polycyclic aromatic hydrocarbons can reach more than 90%. The polycyclic aromatic hydrocarbon soil pollution risk screening value stipulated in the second category of construction land (Trial) can meet the remediation requirements of petroleum and petrochemical enterprises or the surrounding PAH-contaminated soil of abandoned land.

(3) The addition of initiator can stimulate persulfate and peroxide to generate active free radicals, and the generated SO ₄ · ^- and ·OH are mutually excited and work together to achieve the purpose of remediating organic polluted soil. Using the repairing composition and repairing method (application) of the present invention, polycyclic aromatic hydrocarbons are degraded into small molecule organic matter and even completely mineralized, without causing secondary pollution to the environment.

(4) The dual oxidant system not only improves the degradation efficiency of pollutants, but also converts refractory organic matter into easily degradable organic matter. In particular, the application of solid inorganic peroxides in the process of soil remediation can slowly release hydrogen peroxide, increase the effective action time of the oxidant, and give full play to the oxidation effect of the oxidant, thereby improving the efficiency of soil remediation and reducing the cost of remediation. Persulfate can generate free radicals in a wide pH range, making up for the lack of low activity of peroxides under alkaline conditions.

Detailed ways

The present invention will be further described below in conjunction with specific examples, but this does not constitute any limitation to the present invention.

Preparation of contaminated soil samples:

(1) Collect 0-20 cm plow layer soil, remove gravel, animal and plant residues in the soil, dry at 200°C and pass through a 2 mm sieve to obtain non-polluted soil for future use.

(2) Dissolve a certain amount of polycyclic aromatic hydrocarbons in dichloromethane, add the prepared polycyclic aromatic hydrocarbons/dichloromethane solution into the non-polluted soil in the above step (1) under constant stirring, and continue to stir until uniform , placed in a fume hood to allow the solvent to volatilize naturally to obtain PAH-contaminated soil.

According to the different content of added pollutants, different concentrations of polluted soil can be prepared. The content of polycyclic aromatic hydrocarbons in the prepared contaminated soil exceeded the soil pollution risk screening value of various polycyclic aromatic hydrocarbons in the second category of construction land in the "Soil Environmental Quality Construction Land Soil Pollution Risk Control Standard". Based on this, the following remediation tests were carried out.

Example 1

Weigh 10g of prepared naphthalene-contaminated soil, the concentration of naphthalene in the soil is 300ppm, put it in a 50mL centrifuge tube, add 0.5mL ethanol and 30mL water, place it on a rotary shaker, and rotate it at room temperature for 2 hours to obtain a mixture of co-solvent and soil .

Weigh 0.002g of azobisisobutylamidine hydrochloride and 0.1g of sodium persulfate dissolved in 2mL of water to prepare a solution, heat to 50°C, then add the above mixture of co-solvent and soil, and add 0.3g of peroxide Calcium, after mixing evenly with a vortex mixer, place on a rotary shaker and rotate at room temperature for 6 hours.

After the reaction, centrifuge to separate the water phase and the soil phase, discard the water phase, freeze-dry the soil phase, and use n-hexane as the solvent to carry out pressurized solvent extraction with a fast solvent extraction apparatus. Compositional analysis was performed. The results are listed in Table 1.

Example 2

Weigh 10g of contaminated soil prepared with naphthalene, the concentration of naphthalene in the soil is 300ppm, put it in a 50mL centrifuge tube, add 0.5mL ethanol and 50mL water, place it on a rotary shaker, and rotate it at room temperature for 2 hours to obtain a mixture of co-solvent and soil .

Weigh 0.002g of azobisisobutylamidine hydrochloride and 0.1g of sodium persulfate dissolved in 2mL of water to prepare a solution, heat to 50°C, then add the above mixture of co-solvent and soil, and add 0.3g of peroxide Calcium, after mixing evenly with a vortex mixer, place on a rotary shaker and rotate at room temperature for 6 hours.

After the reaction, centrifuge to separate the water phase and the soil phase, discard the water phase, freeze-dry the soil phase, and use n-hexane as the solvent to carry out pressurized solvent extraction with a fast solvent extraction apparatus. Compositional analysis was performed. The results are listed in Table 1.

Example 3

Weigh 10g of prepared naphthalene-contaminated soil, the concentration of naphthalene in the soil is 300ppm, put it in a 50mL centrifuge tube, add 0.5mL ethanol and 30mL water, place it on a rotary shaker, and rotate it at room temperature for 2 hours to obtain a mixture of co-solvent and soil .

Weigh 0.002g of azobisisobutylamidine hydrochloride and 0.2g of sodium persulfate dissolved in 2mL of water to prepare a solution, heat to 50°C, then add to the mixture of the above co-solvent and soil, and add 0.6g of peroxide Calcium, after mixing evenly with a vortex mixer, place on a rotary shaker and rotate at room temperature for 6 hours.

After the reaction, centrifuge to separate the water phase and the soil phase, discard the water phase, freeze-dry the soil phase, and use n-hexane as the solvent to carry out pressurized solvent extraction with a fast solvent extraction apparatus. Compositional analysis was performed. The results are listed in Table 1.

Example 4

Weigh 10g of prepared naphthalene-contaminated soil, the concentration of naphthalene in the soil is 300ppm, put it in a 50mL centrifuge tube, add 0.5mL ethanol and 30mL water, place it on a rotary shaker, and rotate it at room temperature for 2 hours to obtain a mixture of co-solvent and soil .

Weigh 0.002g of azobisisobutylamidine hydrochloride and 0.1g of sodium persulfate dissolved in 2mL of water to prepare a solution, heat to 50°C, then add the above mixture of co-solvent and soil, and add 0.5g of peroxide Calcium, after mixing evenly with a vortex mixer, place on a rotary shaker and rotate at room temperature for 6 hours.

After the reaction, centrifuge to separate the water phase and the soil phase, discard the water phase, freeze-dry the soil phase, and use n-hexane as the solvent to carry out pressurized solvent extraction with a fast solvent extraction apparatus. Compositional analysis was performed. The results are listed in Table 1.

Example 5

Weigh 10g of prepared naphthalene-contaminated soil, the concentration of naphthalene in the soil is 300ppm, put it in a 50mL centrifuge tube, add 0.5mL ethanol and 30mL water, place it on a rotary shaker, and rotate it at room temperature for 2 hours to obtain a mixture of co-solvent and soil .

Weigh 0.002g of azobisisobutylamidine hydrochloride and 0.1g of sodium persulfate dissolved in 2mL of water to prepare a solution, heat to 60°C, then add to the mixture of the above co-solvent and soil, and at the same time add 0.3g of peroxide Calcium, after mixing evenly with a vortex mixer, place on a rotary shaker and rotate at room temperature for 6 hours.

After the reaction, centrifuge to separate the water phase and the soil phase, discard the water phase, freeze-dry the soil phase, and use n-hexane as the solvent to carry out pressurized solvent extraction with a fast solvent extraction apparatus. Compositional analysis was performed. The results are listed in Table 1.

Example 6

Weigh 10g of prepared naphthalene-contaminated soil, the concentration of naphthalene in the soil is 300ppm, put it in a 50mL centrifuge tube, add 0.5mL ethanol and 30mL water, place it on a rotary shaker, and rotate it at room temperature for 2 hours to obtain a mixture of co-solvent and soil .

Weigh 0.002g of azobisisobutylamidine hydrochloride and 0.1g of sodium persulfate dissolved in 2mL of water to prepare a solution, heat to 50°C, then add the above mixture of co-solvent and soil, and add 0.3g of peroxide Calcium, after mixing evenly with a vortex mixer, place on a rotary shaker and rotate at room temperature for 10 hours.

After the reaction, centrifuge to separate the water phase and the soil phase, discard the water phase, freeze-dry the soil phase, and use n-hexane as the solvent to carry out pressurized solvent extraction with a fast solvent extraction apparatus. Compositional analysis was performed. The results are listed in Table 1.

Example 7

Weigh 10g of the prepared naphthalene-contaminated soil, the concentration of naphthalene in the soil is 500ppm, put it in a 50mL centrifuge tube, add 0.5mL ethanol and 30mL water, place it on a rotary shaker, and rotate it at room temperature for 2 hours to obtain a mixture of co-solvent and soil .

Weigh 0.002g of azobisisobutylamidine hydrochloride and 0.1g of sodium persulfate dissolved in 2mL of water to prepare a solution, heat to 50°C, then add the above mixture of co-solvent and soil, and add 0.3g of peroxide Calcium, after mixing evenly with a vortex mixer, place on a rotary shaker and rotate at room temperature for 6 hours.

After the reaction, centrifuge to separate the water phase and the soil phase, discard the water phase, freeze-dry the soil phase, and use n-hexane as the solvent to carry out pressurized solvent extraction with a fast solvent extraction apparatus. Compositional analysis was performed. The results are listed in Table 1.

Example 8

Weigh 10 g of the prepared benzo[a]pyrene-contaminated soil, the concentration of benzo[a]pyrene in the soil is 30ppm, put it in a 50mL centrifuge tube, add 0.5mL ethanol and 30mL water, place on a rotary shaker, and rotate at room temperature After 2 hours, a mixture of co-solvent and soil was obtained.

Weigh 0.002g of azobisisobutylamidine hydrochloride and 0.1g of sodium persulfate dissolved in 2mL of water to prepare a solution, heat to 50°C, then add the above mixture of co-solvent and soil, and add 0.3g of peroxide Calcium, after mixing evenly with a vortex mixer, place on a rotary shaker and rotate at room temperature for 6 hours.

After the reaction, centrifuge to separate the water phase and the soil phase, discard the water phase, freeze-dry the soil phase, and use n-hexane as the solvent to carry out pressurized solvent extraction with a fast solvent extraction apparatus. Compositional analysis was performed. The results are listed in Table 1.

Example 9

Take by weighing 10g of prepared naphthalene-contaminated soil, the concentration of naphthalene in the soil is 300ppm, place in a 50mL centrifuge tube, add 0.5mL isopropanol and 30mL water, place on a rotary shaker, and rotate at room temperature for 2 hours to obtain the concentration of cosolvent and soil. mixture.

Weigh 0.002g of azobisisobutylamidine hydrochloride and 0.1g of sodium persulfate dissolved in 2mL of water to prepare a solution, heat to 50°C, then add the above mixture of co-solvent and soil, and add 0.3g of peroxide Calcium, after mixing evenly with a vortex mixer, place on a rotary shaker and rotate at room temperature for 6 hours.

After the reaction, centrifuge to separate the water phase and the soil phase, discard the water phase, freeze-dry the soil phase, and use n-hexane as the solvent to carry out pressurized solvent extraction with a fast solvent extraction apparatus. Compositional analysis was performed. The results are listed in Table 1.

Example 10

Weigh 10g of prepared naphthalene-contaminated soil, the concentration of naphthalene in the soil is 300ppm, put it in a 50mL centrifuge tube, add 0.5mL ethanol and 30mL water, place it on a rotary shaker, and rotate it at room temperature for 2 hours to obtain a mixture of co-solvent and soil .

Weigh 0.0028g of azobisisobutylamidine hydrochloride and 0.1g of sodium persulfate dissolved in 2.8mL of water to prepare a solution, heat to 50 ° C, then add the above mixture of co-solvent and soil, and at the same time add 0.3g of persulfate Calcium oxide was mixed evenly in a vortex mixer, placed on a rotary shaker, and rotated at room temperature for 6 hours.

After the reaction, centrifuge to separate the water phase and the soil phase, discard the water phase, freeze-dry the soil phase, and use n-hexane as the solvent to carry out pressurized solvent extraction with a fast solvent extraction apparatus. Compositional analysis was performed. The results are listed in Table 1.

Comparative example 1

Weigh 10g of the prepared naphthalene-contaminated soil and place it in a 50mL centrifuge tube. The concentration of naphthalene in the soil is 300ppm. Add 30 mL of deionized water to the centrifuge tube, and use a vortex mixer to mix the contaminated soil and deionized water evenly. Then weigh 0.1g of sodium persulfate and 0.3g of calcium peroxide, 0.3861g of ferrous sulfate and 0.2671g of citric acid and add them to the centrifuge tube. .

After the reaction, centrifuge to separate the water phase and the soil phase, discard the water phase, freeze-dry the soil phase, and use n-hexane as the solvent to carry out pressurized solvent extraction with a fast solvent extraction apparatus. After the extract is concentrated to a constant volume, use gas chromatography Compositional analysis was performed. The results are listed in Table 1.

Comparative example 2

The naphthalene-contaminated soil was repaired in the same manner as in Example 1, except that ethanol was not used as a cosolvent.

After the reaction, centrifuge to separate the water phase and the soil phase, discard the water phase, freeze-dry the soil phase, and use n-hexane as the solvent to carry out pressurized solvent extraction with a fast solvent extraction apparatus. After the extract is concentrated to a constant volume, use gas chromatography Compositional analysis was performed. The results are listed in Table 1.

Table 1 Experimental results (ppm)

Example Pollutants initial pollutant concentration Residual Pollutant Concentration Degradation rate(%) 1 naphthalene 300 twenty three 92.3 2 naphthalene 300 20 93.3 3 naphthalene 300 9 97 4 naphthalene 300 twenty one 93 5 naphthalene 300 14 95.3 6 naphthalene 300 17 94.3 7 naphthalene 500 43 91.4 8 Benzo[a]pyrene 30 1.1 96.3 9 naphthalene 300 25 91.7 10 naphthalene 300 16 94.7 Comparative example 1 naphthalene 300 62 79.3 Comparative example 2 naphthalene 300 54 82.0

As can be seen from the above results, using the restoration composition of the present invention, by adding cosolvent and a small amount of initiator, under the condition of not using catalyst and chelating agent, the double oxidizing agent system composed of calcium peroxide and sodium persulfate is effective for many Aromatic hydrocarbon-contaminated soil has a good remediation effect, the degradation rate of polycyclic aromatic hydrocarbons in the soil is greater than 90%, and the content of polycyclic aromatic hydrocarbons in the soil after remediation is lower than the "Soil Environmental Quality Construction Land Soil Pollution Risk Control Standard (Trial)" The soil pollution risk screening value of various polycyclic aromatic hydrocarbons in the second type of construction land has a good application prospect.

It should be noted that the above-mentioned embodiments are only used to explain the present invention, and do not constitute any limitation to the present invention. The invention has been described with reference to typical embodiments, but the words which have been used therein are words of description and explanation rather than words of limitation. The present invention can be modified as prescribed within the scope of the claims of the present invention, and the present invention can be revised without departing from the scope and spirit of the present invention. Although the invention described therein refers to specific methods, materials and examples, it is not intended that the invention be limited to the specific examples disclosed therein, but rather, the invention extends to all other methods and applications having the same function.

Claims (10)

1. A remediation composition for polycyclic aromatic hydrocarbon contaminated soil, wherein the remediation composition comprises a persulfate, a peroxide, a free radical initiator, and a co-solvent.

2. Repair composition according to claim 1, wherein the peroxide is a solid inorganic peroxide, preferably calcium peroxide and/or magnesium peroxide; and/or the presence of a gas in the gas,

the persulfate is at least one selected from sodium persulfate, potassium persulfate and ammonium persulfate, and preferably is sodium persulfate and/or potassium persulfate.

3. Repair composition according to claim 1 or 2, wherein the mass ratio between the peroxide and the persulfate is 1:2-8, preferably 1:3-6.

4. The remedial composition according to any of claims 1 to 3, wherein the free radical initiator is a water-soluble azo-based initiator, preferably at least one of azobisisobutylamidine hydrochloride, azobisisobutylimidazoline sulfate, azobiscyanovaleric acid, and azobisdiisopropylimidazoline; and/or

The ratio of the mass of the peroxide and the persulfate to the mass of the radical initiator is 1.

5. The repair composition according to any of claims 1 to 4, wherein the co-solvent is a monohydric or dihydric alcohol having 1 to 6 carbon atoms, preferably a monohydric or dihydric alcohol having 2 to 4 carbon atoms, more preferably at least one selected from the group consisting of ethanol, n-propanol, isopropanol, n-butanol, isobutanol, ethylene glycol, 1,3-propanediol and 1,4 butanediol; and/or

The co-solvent is used in an amount of 50 to 200ml, preferably 100 to 150ml, relative to 100g of the peroxide and the persulfate.

6. Use of the remedial composition according to any of claims 1 to 5 for remediating polycyclic aromatic hydrocarbon contaminated soil.

7. The use according to claim 6, wherein the polycyclic aromatic hydrocarbon is selected from at least one of naphthalene, phenanthrene, anthracene, pyrene, benzo [ a ] pyrene and/or benzo [ b ] fluoranthene; and/or the grain diameter of the polycyclic aromatic hydrocarbon-polluted soil is less than 2 mm.

8. Use according to claim 6 or 7, characterized in that it comprises the following steps:

s100, adding a first part of water and a cosolvent into the polycyclic aromatic hydrocarbon polluted soil, and mixing to obtain a first mixture;

s200, mixing an initiator, persulfate and second part of water, and heating to obtain a second solution;

s300, mixing the peroxide, the first mixture obtained in the step S100 and the second solution obtained in the step S200;

preferably, in step S100, the co-solvent is used in an amount of 20 to 80ml, preferably 40 to 60ml, for example, 50ml, per kg of the polycyclic aromatic hydrocarbon-contaminated soil; and/or, for each kilogram of soil polluted by the polycyclic aromatic hydrocarbon, the using amount of the first part of water is 3 kg-5 kg; and/or the mixing time in the step S100 is 1 to 3 hours.

9. The use according to claim 8, wherein in step S200, the persulfate is used in an amount of 5 to 20g per kg of the polycyclic aromatic hydrocarbon-contaminated soil; and/or the mass ratio of the initiator to the second portion of water is 1; and/or the heating temperature in the step S200 is 50-65 ℃.

10. Use according to claim 8 or 9, wherein the mixing treatment in step S300 is carried out for a period of time of 1 to 12 hours, preferably 6 to 10 hours; and/or the mixing treatment is performed at normal temperature.