CN114907856A - A green and efficient polycyclic aromatic hydrocarbon-contaminated soil remediation leaching agent and application method - Google Patents

Abstract

The invention discloses a green and efficient polycyclic aromatic hydrocarbon-contaminated soil remediation leaching agent and an application method, which belong to the technical field of site soil remediation. The invention effectively realizes green and efficient leaching and remediation of soil polycyclic aromatic hydrocarbons by screening suitable eluent components and scientifically setting the eluent component distribution ratio, solid-liquid ratio and elution time, and solves the problem of many problems in existing eluent remediation. Cyclic aromatic hydrocarbon-contaminated soil has problems such as poor leaching effect, long-term residual and toxicity of active ingredients of leaching agent.

Description

A green and efficient polycyclic aromatic hydrocarbon-contaminated soil remediation leaching agent and application method

technical field

The invention belongs to the technical field of site soil remediation, and more particularly relates to a green and efficient polycyclic aromatic hydrocarbon-contaminated soil remediation leaching agent and an application method.

Background technique

Polycyclic aromatic hydrocarbons (PAHs) are persistent organic pollutants composed of two or more benzene rings combined in a linear, angular or cluster form, and are by-products of incomplete combustion or pyrolysis of organic matter. Most PAHs are pale yellow or colorless crystals with high boiling point, high melting point and low water solubility. PAHs are inert and stable in chemical properties, and widely exist in various environmental media. Some high-molecular-weight PAHs have been proven to have "three causes" effects such as carcinogenicity, teratogenicity, and mutagenesis, which have attracted much attention. PAHs are mainly derived from biometabolic synthesis, geochemical synthesis of fossil fuels and mineral formation, and human activities. In recent years, the content of PAHs in the environment has been greatly increased due to human activities, and it has become the main source of PAHs in the environment. Although the content of polycyclic aromatic hydrocarbons in the environment is relatively small, they are widely distributed in the air, soil and water bodies, and enter the human body through respiration, diet, etc. and enrich, thus endangering human health. About 90% of the PAHs in the environment exist in the soil. PAHs can affect the composition, structure, and soil enzyme activity of soil microorganisms, thereby affecting the structure and function of soil ecosystems, causing serious pressure on soil microbial communities.

At present, the use of leaching and remediation methods to remove PAH pollutants in soil is one of the best methods. However, due to the strong hydrophobicity of PAHs, the effect in the actual leaching process is often poor. Surfactant is a natural or synthetic amphiphilic molecule that can reduce the surface tension of the solvent and change the interface state of the system by adding a small amount to produce wetting, dispersing, emulsification and solubilization. At present, my country has achieved some results in the remediation of organically polluted soil by using surfactants, but there are still problems in the remediation of organically polluted soil leaching agents. In the face of complex conditions such as soil physical and chemical properties, pollutant characteristics, etc. The choice of eluent, and there are still problems of unstable performance and poor elution effect in the actual elution process. At the same time, the residual and toxicity of the active ingredients of the eluent also bring about the problem of secondary pollution of the environment. Therefore, there is an urgent need to develop and obtain a polycyclic aromatic hydrocarbon-contaminated soil leaching agent that can effectively achieve high-efficiency leaching and remediation of soil polycyclic aromatic hydrocarbons.

SUMMARY OF THE INVENTION

1. The problem to be solved

Aiming at the problems of poor leaching effect, long-term residual and toxicity of the effective components of the leaching agent in the existing leaching and remediation of polycyclic aromatic hydrocarbon-contaminated soil, the present invention provides a green and efficient polycyclic aromatic hydrocarbon-contaminated soil remediation eluting agent and an application method. The present invention effectively realizes green and efficient leaching and remediation of soil polycyclic aromatic hydrocarbons by screening suitable eluting agent components and scientifically setting the eluting agent component distribution ratio, solid-liquid ratio and leaching time.

2. Technical solutions

In order to solve the above problems, the technical scheme adopted in the present invention is as follows:

A polycyclic aromatic hydrocarbon-contaminated soil remediation and leaching agent of the present invention comprises plant polyene phenol polyoxyethylene ether and polyethylene glycol as active ingredients, and the quality of the plant polyene phenol polyoxyethylene ether and polyethylene glycol is The ratio is 9:5 to 45:1.

Preferably, in terms of mass percentage, the rinsing agent comprises plant polyene phenol polyoxyethylene ether: 0.18%-0.9%, polyethylene glycol: 0.02%-0.1%, water: 99.8%-99%.

A method for remediating polycyclic aromatic hydrocarbon-contaminated soil of the present invention comprises contacting the eluting agent with the polycyclic aromatic hydrocarbon-contaminated soil to wash and remediate the polycyclic aromatic hydrocarbon-contaminated soil.

Preferably, a method for remediating polycyclic aromatic hydrocarbon-contaminated soil of the present invention specifically comprises the following steps:

S10. Remove impurities from the PAH-contaminated soil, grind it, pass through a 60-mesh sieve, and store it in an airtight brown bottle at -20°C for later use;

S20, placing the polycyclic aromatic hydrocarbon-contaminated soil in step S10 in a container, adding a leaching agent, and performing leaching and repairing on the soil at 25°C;

S30. Centrifuge, stand to obtain a soil-water separation, freeze-dry the repaired soil sample, extract polycyclic aromatic hydrocarbons by ultrasonic, purify the extract with a solid-phase extraction column, and measure the residual polycyclic aromatic hydrocarbons by liquid chromatography , the removal rate of PAHs was obtained.

Preferably, the solid-liquid ratio between the polycyclic aromatic hydrocarbon-contaminated soil and the eluent is 1:20 to 1:80.

Preferably, the rinsing time is 4-24 hours.

Preferably, the mass concentration of the active ingredient of the eluent is 5g/L～10g/L.

More preferably, the solid-liquid ratio between the polycyclic aromatic hydrocarbon-contaminated soil and the eluent is 1:40.

More preferably, the rinsing time is 12 hours.

Preferably, the polycyclic aromatic hydrocarbon-contaminated soil contains 100-1000 ppm of polycyclic aromatic hydrocarbons.

3. Beneficial effects

Compared with the prior art, the beneficial effects of the present invention are:

(1) A kind of polycyclic aromatic hydrocarbon-contaminated soil remediation and leaching agent of the present invention, selects a fully biodegradable plant-derived nonionic surfactant, that is, plant polyene phenol polyoxyethylene ether as an active ingredient, and also contains biodegradable non-ionic surfactants. For the degraded polyethylene glycol, by reasonably setting the proportioning relationship between the components of the eluent, the efficient removal of 100-1000 ppm polycyclic aromatic hydrocarbon-contaminated soil can be achieved, and the removal rate of polycyclic aromatic hydrocarbons is as high as 75% or more;

(2) The polycyclic aromatic hydrocarbon-contaminated soil remediation eluting agent of the present invention avoids the problem of secondary pollution when traditional surfactants are used to remediate the polycyclic aromatic hydrocarbon-contaminated soil, and the eluent composition is environmentally friendly and completely bioavailable. Degradation, excellent emulsifying and dispersing properties, good washing properties, low foaming, etc.;

(3) The method for remediating polycyclic aromatic hydrocarbon-contaminated soil of the present invention can achieve efficient removal of soil polycyclic aromatic hydrocarbons under certain conditions of eluent ratio, solid-liquid ratio and leaching time, while remaining leaching The active ingredients of the agent can be efficiently biodegraded under natural conditions, and the degree of biodegradation on the seventh day is 100%.

Description of drawings

Fig. 1 is the schematic diagram of the elution effect of different eluents on soil polycyclic aromatic hydrocarbons of embodiment 1 of the present invention;

2 is a schematic diagram of the elution effect of different solid-liquid ratios on soil PAHs in Example 2 of the present invention;

3 is a schematic diagram of the elution effect of active ingredient concentration on soil polycyclic aromatic hydrocarbons in different eluents of Example 3 of the present invention;

FIG. 4 is a schematic diagram of the elution effect of soil polycyclic aromatic hydrocarbons with different elution times in Example 4 of the present invention.

Detailed ways

The structures, proportions, sizes, etc. shown in the accompanying drawings of this specification are only used to cooperate with the contents disclosed in the specification for the understanding and reading of those who are familiar with the technology, and are not used to limit the conditions for the implementation of the present invention. Therefore, Without technical substantive significance, any structural modification, proportional relationship change or size adjustment should still fall within the technology disclosed in the present invention without affecting the effect that the present invention can produce and the purpose that can be achieved. content can be covered. Meanwhile, the various embodiments of the present invention are not independent of each other, but can be combined.

The present invention will be further described below with reference to specific embodiments.

Example 1

A kind of polycyclic aromatic hydrocarbon-contaminated soil remediation method of the present embodiment, the specific steps are as follows:

S10. Remove impurities from the polycyclic aromatic hydrocarbons (PHE, PYR, BaP) polluted soil, grind, pass through a 60-mesh sieve, and store in an airtight brown bottle at -20°C for later use;

S20. Take 1 g of contaminated soil and place it in a 50 mL centrifuge tube, add an eluent, and the components of the eluent are 0.45% by mass of plant polyenol polyoxyethylene ether, 0.05% by mass of polyethylene glycol and 99.5% by mass of polyethylene glycol. water, the mass concentration of the active ingredient of the eluent is 5g/L; the solid-liquid ratio is set to 1:40, and each sample is set to 3 parallel samples; then the centrifuge tube is placed on a constant temperature shaker and shaken horizontally for 12h (25℃, 150r/min);

S30. Centrifuge the centrifuge tube at a high speed (3000r, 10min), and after standing, obtain a soil-water separator, and use 10mL of an extractant (n-hexane:dichloromethane=1:1) for the restored soil sample to ultrasonically extract for 1h, and take 5mL of The lower extract was passed through a solid-phase extraction column (SPE, the solid-phase extraction column was filled with 1 g of anhydrous sodium sulfate/silica gel/Flory silica/anhydrous sodium sulfate from bottom to top), and the purified solution was placed on a rotary evaporator again. Concentrate to 2 mL, add 1 mL of acetonitrile and concentrate to less than 1 mL, use acetonitrile to make up to 1 mL, and use liquid chromatography to determine the removal rate of polycyclic aromatic hydrocarbons >75%.

Example 2

The basic content of this embodiment is the same as that of Embodiment 1, and the difference is: a method for remediation of polycyclic aromatic hydrocarbon-contaminated soil in this embodiment, the specific steps are as follows:

S10. Remove impurities from the polycyclic aromatic hydrocarbons (PHE, PYR, BaP) polluted soil, grind, pass through a 60-mesh sieve, and store in an airtight brown bottle at -20°C for later use;

S20. Take a certain amount of polluted soil and place it in a 50 mL centrifuge tube, add a eluting agent, and the components of the eluting agent are 0.45% by mass of plant polyene phenol polyoxyethylene ether, 0.05% by mass of polyethylene glycol and 0.05% by mass of polyethylene glycol. 99.5% water, the mass concentration of the active ingredient of the eluent is 5g/L; 1:5, set 3 parallel samples for each sample; then place the centrifuge tube on a constant temperature shaker and shake horizontally for 12h (25°C, 150r/min);

S30. Centrifuge the centrifuge tube at a high speed (3000r, 10min), and then stand to obtain a soil-water separator, perform ultrasonic extraction of polycyclic aromatic hydrocarbons on the restored soil sample, use a solid-phase extraction column to purify the extract, and measure it by a liquid chromatograph PAHs remain, and the removal rate of PAHs is obtained.

As shown in Figure 2, the removal rates of phenanthrene, pyrene and benzo[a]pyrene increased with the increase of the eluent volume. increase, thereby increasing the elution removal efficiency. The solid-liquid ratio increased from 1:5 to 1:100, the amount of eluent increased by 20 times, and the removal rates of phenanthrene, pyrene and benzo[a]pyrene increased from 13.3%, 10.4%, 11.6% to 82.8%, 89.5% and 72.8%. When the volume of the eluent was increased to a solid-liquid ratio of 1:40, the PAHs removal rate was >75%.

After that, the removal rate of PAHs increased slowly with the increase of the amount of eluent. At this time, the removal rate of PAHs reached 85.2% of the removal rate of 1:100. Therefore, the appropriate amount of eluent added is a solid-liquid ratio of 1:40.

Example 3

The basic content of this embodiment is the same as that of Embodiment 1, and the difference is: a method for remediation of polycyclic aromatic hydrocarbon-contaminated soil in this embodiment, the specific steps are as follows:

S10. Remove impurities from the polycyclic aromatic hydrocarbons (PHE, PYR, BaP) polluted soil, grind, pass through a 60-mesh sieve, and store in an airtight brown bottle at -20°C for later use;

S20. Take 1 g of contaminated soil and place it in a 50 mL centrifuge tube, add a eluting agent, and the eluting agent contains, in mass percentage, plant polyenol polyoxyethylene ether: 0.08%-1.8%, polyethylene glycol: 0.02%-0.2 %, water: 99.9%-98%, the corresponding active ingredient concentrations in the eluent are 1g/L, 2g/L, 5g/L, 10g/L, 20g/L, respectively. The solid-liquid ratio was set to 1:40, and three parallel samples were set for each sample; then the centrifuge tube was placed on a constant temperature shaker and horizontally shaken for 12h (25°C, 150r/min);

S30. Centrifuge the centrifuge tube at a high speed (3000r, 10min), and then stand to obtain a soil-water separator, perform ultrasonic extraction of polycyclic aromatic hydrocarbons on the restored soil sample, use a solid-phase extraction column to purify the extract, and measure it by a liquid chromatograph PAHs remain, and the removal rate of PAHs is obtained.

As shown in Figure 3, when the concentration of the active ingredients of the eluent is 5g/L, the total PAHs removal rate reaches about 60%. After continuing to increase the active ingredients of the eluent to 10g/L, the PAHs removal rate is >75%.

Example 4

The basic content of this embodiment is the same as that of Embodiment 1, and the difference is: a method for remediation of polycyclic aromatic hydrocarbon-contaminated soil in this embodiment, the specific steps are as follows:

S10. Remove impurities from the polycyclic aromatic hydrocarbons (PHE, PYR, BaP) polluted soil, grind, pass through a 60-mesh sieve, and store in an airtight brown bottle at -20°C for later use;

S20. Take 1 g of contaminated soil and place it in a 50 mL centrifuge tube, add an eluent, and the components of the eluent are 0.45% by mass of plant polyenol polyoxyethylene ether, 0.05% by mass of polyethylene glycol and 99.5% by mass of polyethylene glycol. water, the mass concentration of the active ingredient of the eluent is 5g/L; the solid-liquid ratio is set to 1:40, and three parallel samples are set for each sample; then the centrifuge tube is placed on a constant temperature shaker, and the The time gradient is set to 0.5h, 1h, 4h, 12h, 16h, 20h, 24h, 30h (25°C, 150r/min);

S30. Centrifuge the centrifuge tube at a high speed (3000r, 10min), and then stand to obtain a soil-water separator, perform ultrasonic extraction of polycyclic aromatic hydrocarbons on the restored soil sample, use a solid-phase extraction column to purify the extract, and measure it by a liquid chromatograph PAHs remain, and the removal rate of PAHs is obtained.

As shown in Figure 4, the eluent in this example can only elute 51.4% of phenanthrene, 38.7% of pyrene and 34.5% of benzo[a]pyrene within 1 h, and the average elution rate of PAHs is 41.5%. After 4 h, the removal rate of PAHs increased gradually with the increase of elution time. After the elution time reached 12h, the removal rate of PAHs was stable (>50%), and then the removal rate of PAHs increased slowly with time. Considering the time cost and the leaching efficiency comprehensively, the leaching time of the eluent of the present invention is 4-24h, among which 12h is the most suitable.

Comparative Example 1

The basic content of this comparative example is the same as that of Example 1, except that: this comparative example provides the following 10 kinds of eluents to investigate the elution effect of soil PAHs: eluents of Example 1, dodecylsulfonic acid Sodium (SDS), Sodium Dodecylbenzene Sulfonate (SDBS), 2-Hydroxypropyl-β-cyclodextrin (HPCD), Poly 23 Dodecyl Ether (Brij-35), Saponin (Saponin) ; Sophorolipids (Sop), lactose-type sophorolipids (Sop-1).

As shown in Figure 1, the elution effects of these 10 surfactants on soil PAHs were very different. Among them, the removal rate of the total PAHs of the eluent in Example 1 is >75%, the removal rate of Brij-35 to the total PAHs in the soil is about 50%, and the removal rate of the total PAHs by HPCD and Sop is less than 10%. Difference. The removal rate of SDS, SDBS and Sop-1 to the total soil PAHs was less than 1%, indicating that they had no effect on PAHs elution.

Therefore, the above results show that under the same conditions of use, the leaching agent of Example 1 is more efficient in leaching and remediation of soil PAHs than other commonly used leaching agents in the market.

The present invention has been described in detail above with reference to specific exemplary embodiments. However, it should be understood that various modifications and variations can be made without departing from the scope of the present invention as defined by the appended claims. The detailed description and drawings are to be regarded in an illustrative rather than a restrictive sense, and if any such modifications and variations exist, they will fall within the scope of the invention described herein. In addition, the background art is intended to illustrate the research and development status and significance of the present technology, and is not intended to limit the present invention or the application and application fields of the present invention.

More particularly, although exemplary embodiments of the present invention have been described herein, the present invention is not limited to these embodiments, but includes modifications, omissions, Any and all embodiments such as combinations, adaptations and/or substitutions between the various embodiments. The definitions in the claims are to be construed broadly according to the language applied in the claims, and are not limited to the examples described in the foregoing detailed description or during the practice of this application, which examples are to be considered non-exclusive. Any steps recited in any method or process claims may be performed in any order and are not limited to the order presented in the claims. Accordingly, the scope of the invention should be determined only by the appended claims and their legal equivalents, rather than by the description and examples given above.

Claims (10)

1. a polycyclic aromatic hydrocarbon-polluted soil remediation leaching agent, is characterized in that: comprise plant polyenol polyoxyethylene ether and polyethylene glycol as active ingredient, described plant polyenol polyoxyethylene ether and polyethylene glycol The mass ratio of alcohol is 9:5 to 45:1. 2 . The leaching agent for remediation of polycyclic aromatic hydrocarbon-contaminated soil according to claim 1 , wherein, in terms of mass percentage, the leaching agent comprises plant polyene phenol polyoxyethylene ether: 0.18% to 0.9% 2 . , polyethylene glycol: 0.02% to 0.1%, water: 99.8% to 99%. 3. A method for remediating polycyclic aromatic hydrocarbon-contaminated soil, characterized in that: comprising contacting the eluting agent according to claim 1 or 2 with the polycyclic aromatic hydrocarbon-contaminated soil, to wash and repair the polycyclic aromatic hydrocarbon-contaminated soil. 4. a kind of polycyclic aromatic hydrocarbon-contaminated soil remediation method according to claim 3, is characterized in that, described method specifically comprises the following steps: S10. Remove impurities from the PAH-contaminated soil, grind it, pass through a 60-mesh sieve, and store it in an airtight brown bottle at -20°C for later use; S20, placing the polycyclic aromatic hydrocarbon-contaminated soil in step S10 in a container, adding a leaching agent, and performing leaching and repairing on the soil at 25°C; S30. Centrifuge, stand to obtain a soil-water separation, freeze-dry the repaired soil sample, extract polycyclic aromatic hydrocarbons by ultrasonic, purify the extract with a solid-phase extraction column, and measure the residual polycyclic aromatic hydrocarbons by liquid chromatography , the removal rate of PAHs was obtained. 5 . The method for remediating polycyclic aromatic hydrocarbon-contaminated soil according to claim 3 , wherein the solid-liquid ratio between the polycyclic aromatic hydrocarbon-contaminated soil and the eluent is 1:20 to 1:80. 6 . . 6 . The method for remediating polycyclic aromatic hydrocarbon-contaminated soil according to claim 3 , wherein the leaching time is 4 to 24 hours. 7 . 7 . The method for remediation of polycyclic aromatic hydrocarbon-contaminated soil according to claim 3 , wherein the mass concentration of the active ingredient of the eluent is 5 g/L to 10 g/L. 8 . 8 . The method for remediating polycyclic aromatic hydrocarbon-contaminated soil according to claim 5 , wherein the solid-liquid ratio between the polycyclic aromatic hydrocarbon-contaminated soil and the eluent is 1:40. 9 . 9 . The method for remediating polycyclic aromatic hydrocarbon-contaminated soil according to claim 5 , wherein the leaching time is 12 hours. 10 . 10 . The method for remediating polycyclic aromatic hydrocarbon-contaminated soil according to claim 3 , wherein the polycyclic aromatic hydrocarbon-contaminated soil contains 100-1000 ppm of polycyclic aromatic hydrocarbons. 11 .

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