A leaching solution and a method for remediating petroleum hydrocarbon-contaminated soil using the same.

Abstract

This invention provides a leaching solution and a method for remediating petroleum hydrocarbon-contaminated soil using the same. The leaching solution comprises: anionic surfactant, nonionic surfactant, inorganic additives, and water. The anionic surfactant is selected from at least one of alkylbenzene sulfonate surfactants and fatty alcohol polyoxyethylene ether sulfate surfactants; the nonionic surfactant is selected from at least one of alkyl glycoside surfactants; and the inorganic additives are selected from silicates and metasilicates. This invention, through the combined use of specific types of anionic surfactants, nonionic surfactants, and inorganic additives, produces a leaching solution that is highly efficient, safe, environmentally friendly, and economical, providing technical support for mitigating current petroleum hydrocarbon pollution of soil, particularly for the remediation of petroleum hydrocarbon-contaminated soil around oil fields and oil depots.

Description

Technical Field

[0001] This invention relates to the field of soil pollution control and remediation, specifically to a leaching solution and a method for remediating petroleum hydrocarbon-contaminated soil using the same. Background Technology

[0002] Currently, my country faces a severe soil pollution situation, with oil-contaminated soil being a prominent issue. Data shows that since 1978, nearly 100,000 tons of soil have been contaminated by oil, covering an area of ​​80 million square meters. 2 Nearly 600,000 tons of petroleum pollutants enter the environment each year, and nearly 1.0 × 10⁻⁶ tons of new soil are polluted. 8 kg; in most soil samples collected within 100 meters of oil wells in some oilfields, the content of petroleum pollutants was far higher than the pollution threshold, with some soil samples even containing crude oil content reaching 10,000 mg / kg. Petroleum-contaminated soil problems seriously affect the economic development and ecological environment of my country's oilfield areas, becoming a constraint on the sustainable development of local society, economy, and environment. Therefore, the remediation of petroleum-contaminated soil has become a hot topic in current environmental research and one of the most urgent problems to be solved.

[0003] Common remediation technologies for petroleum-contaminated soil include physical remediation, chemical remediation, and microbial remediation. Physical remediation involves large-scale engineering projects and is costly, making it unsuitable for large-scale remediation. Bioremediation has a long cycle and is significantly affected by the dominant microorganisms, making it unsuitable for rapid remediation of contaminated soil. Chemical remediation is fast, efficient, easy to operate, and widely applicable, often used for the remediation of large-area contaminated sites. Leaching remediation uses a liquid (i.e., leaching solution) that promotes the dissolution / migration of pollutants in the soil to leach the contaminated soil, causing pollutants adsorbed or fixed on soil particles to detach from the soil particles and enter the liquid phase, thereby reducing the pollutant content in the soil. This chemical remediation technology is commonly used for the remediation of large-area, high-concentration petroleum hydrocarbon contaminated sites.

[0004] Leaching solution is a key factor affecting soil leaching efficiency, and its development has always been an important aspect of soil leaching technology research. Chinese patent "A leaching agent for remediation of petroleum hydrocarbon-contaminated soil and its preparation and application" (application number: 201810198339.5, patent 1) discloses a leaching agent for remediation of petroleum hydrocarbon-contaminated soil: an aqueous solution containing a biosurfactant and a sodium salt, wherein the biosurfactant is one or more of rhamnolipid, fructose lipolipid, sucrose lipolipid, sophorolipid, polymyxin, or tea saponin. The sodium salt can be one or more of sodium silicate, sodium lignin, sodium carbonate, sodium acetate, or sodium humate. Chinese patent "A method, leaching device, and washing solution for continuous leaching treatment of petroleum-contaminated soil" (application number: 201810951941.1, patent 2) provides a washing solution for continuous leaching treatment of oil-contaminated soil, which is a mixed aqueous solution of anionic or nonionic surfactants, alcohols, and electrolytes. The anionic surfactant is sodium dodecylbenzenesulfonate or sodium dodecyl sulfate, the nonionic surfactant is Tween-20 or Tween-80, the alcohol is n-butanol or n-pentanol, and the electrolyte is sodium chloride, sodium sulfate, potassium chloride, or potassium sulfate. Although both of these leaching solutions can effectively remove petroleum hydrocarbons from soil and achieve good leaching results, they still have problems such as large reagent dosage, high leaching costs, difficulty in promotion, and potential secondary pollution. Chinese patent "A Mixed Formulation for Remediating Petroleum-Contaminated Soil" (application number: 201910949548.3) discloses a mixed formulation for remediating petroleum-contaminated soil, comprising an emulsifying functional bacterial fermentation broth and an anionic surfactant solution. The emulsifying functional bacteria are screened from oilfield produced water, and the emulsifying functional bacterial fermentation broth is obtained after inoculation and expansion culture of the emulsifying functional bacteria. The anionic surfactant solution is an aqueous solution of sodium ethoxylated alkyl sulfate (AES). This mixed formulation reduces the amount of anionic surfactants used, which alleviates secondary pollution to the soil to some extent. However, its disadvantages are that it is difficult to produce emulsified functional bacterial fermentation liquid on a large scale and the remediation cycle is long. Summary of the Invention

[0005] In view of the problems existing in the prior art, one of the objectives of this invention is to provide a leachate formulated with anionic surfactants, nonionic surfactants, and inorganic additives, and further selecting specific types of anionic surfactants, nonionic surfactants, and inorganic additives. The resulting leachate has the advantages of high efficiency, safety, environmental friendliness, and economy, providing technical support for alleviating current petroleum hydrocarbon pollution of soil, especially for the remediation of petroleum hydrocarbon-contaminated soils around oil fields and oil depots.

[0006] The second objective of this invention is to provide a method for preparing a rinsing solution corresponding to the first objective.

[0007] A third objective of this invention is to provide a method for remediating petroleum hydrocarbon-contaminated soil, corresponding to the above-mentioned objective.

[0008] To achieve one of the above objectives, the technical solution adopted by the present invention is as follows:

[0009] A rinsing solution includes: anionic surfactant, nonionic surfactant, inorganic additives, and water, wherein,

[0010] The anionic surfactant is selected from at least one of alkylbenzene sulfonate surfactants and fatty alcohol polyoxyethylene ether sulfate surfactants;

[0011] The nonionic surfactant is selected from at least one of alkyl glycoside surfactants; and

[0012] The inorganic additives are selected from silicates and metasilicates.

[0013] According to the present invention, the alkylbenzene sulfonate surfactant includes at least one of sodium dodecylbenzene sulfonate and sodium hexadecylbenzene sulfonate.

[0014] According to the present invention, the fatty alcohol polyoxyethylene ether sulfate surfactant includes at least one of fatty alcohol polyoxyethylene ether potassium sulfate and fatty alcohol polyoxyethylene ether sodium sulfate.

[0015] In some preferred embodiments of the present invention, the anionic surfactant is sodium dodecylbenzenesulfonate and / or sodium fatty alcohol polyoxyethylene ether sulfate.

[0016] In this invention, the molecular formula of the sodium fatty alcohol polyoxyethylene ether sulfate is RO(CH2CH2O). n SO3Na (n = 2 or 3, R is C) 12 ~C 15 Alkyl group). In some specific embodiments of the present invention, the sodium lauryl alcohol polyoxyethylene ether sulfate is sodium lauryl alcohol polyoxyethylene ether sulfate.

[0017] In some preferred embodiments of the present invention, the nonionic surfactant is selected from at least one of APG0810, APG0814, APG1214, APG0816, APG1216, APG10, APG12 and APG14.

[0018] In some preferred embodiments of the present invention, the inorganic additive is sodium silicate and / or sodium metasilicate.

[0019] In some preferred embodiments of the present invention, the concentration of the anionic surfactant in the rinsing solution is 0.6 g / L-2.0 g / L.

[0020] In some preferred embodiments of the present invention, the concentration of the nonionic surfactant in the rinsing solution is 3.0 g / L-5.0 g / L.

[0021] In some preferred embodiments of the present invention, the concentration of the inorganic additive is 5.0 g / L-15.0 g / L.

[0022] In some preferred embodiments of the present invention, the mass ratio of the anionic surfactant to the nonionic surfactant in the rinsing solution is 1:(1-10), preferably 1:(2-5).

[0023] In some preferred embodiments of the present invention, the ratio of the total mass of the anionic surfactant and the nonionic surfactant to the mass of the inorganic auxiliary is 1:(2-10), preferably 1:(2.5-5).

[0024] To achieve the second objective mentioned above, the technical solution adopted by the present invention is as follows:

[0025] A method for preparing the rinsing solution according to any one of the above embodiments includes:

[0026] The anionic surfactant, the nonionic surfactant, the inorganic additive, and the water are mixed to prepare the rinsing solution.

[0027] In some preferred embodiments of the present invention, the preparation method includes:

[0028] S1. Dissolve the anionic surfactant in water to obtain an anionic surfactant solution;

[0029] S2. Dissolve the nonionic surfactant in water to obtain a nonionic surfactant solution;

[0030] S3. The anionic surfactant solution, the nonionic surfactant solution, the inorganic additive, and optionally water are mixed to obtain the rinsing solution.

[0031] According to the present invention, the order of steps S1 and S2 is not particularly restricted. Step S1 can be performed first and then step S2, or step S2 can be performed first and then step S1. If conditions permit, steps S1 and S2 can also be performed simultaneously.

[0032] According to the present invention, the volume ratio of water added in step S3 to the anionic surfactant solution is (0-5):(2-5).

[0033] According to the present invention, the volume ratio of water added in step S3 to the nonionic surfactant solution is (0-5):(3-5).

[0034] In some preferred embodiments of the present invention, the preparation method includes:

[0035] 1) Dissolve the anionic surfactant in water to obtain an anionic surfactant solution;

[0036] 2) Dissolve the nonionic surfactant in water to obtain a nonionic surfactant solution;

[0037] 3) Mix the anionic surfactant solution, the nonionic surfactant solution, and optionally water to obtain a mixed solution;

[0038] 4) Mix the mixed solution with an inorganic additive to obtain the rinsing solution.

[0039] According to the present invention, the order of steps 1) and 2) is not particularly restricted. Step 1) can be performed first, followed by step 2), or step 2) can be performed first, followed by step 1). If conditions permit, steps 1) and 2) can also be performed simultaneously.

[0040] In some preferred embodiments of the present invention, the concentration of the anionic surfactant in the anionic surfactant solution is 2 g / L-5 g / L; and the concentration of the nonionic surfactant in the nonionic surfactant solution is 6 g / L-10 g / L.

[0041] In some preferred embodiments of the present invention, in step S3 or step 3), the volume ratio of the anionic surfactant solution to the nonionic surfactant solution is (2-5):(3-5).

[0042] According to the present invention, the volume ratio of water added in step 3) to the anionic surfactant solution is (0-5):(2-5).

[0043] According to the present invention, the volume ratio of water added in step 3) to the nonionic surfactant solution is (0-5):(3-5).

[0044] To achieve the third objective mentioned above, the technical solution adopted by the present invention is as follows:

[0045] A method for remediating petroleum hydrocarbon-contaminated soil includes:

[0046] The leachate solution used in any one of the above embodiments or the leachate solution prepared according to any one of the above embodiments is used to leach petroleum hydrocarbon contaminated soil.

[0047] In some preferred embodiments of the present invention, the ratio between the mass of the petroleum hydrocarbon-contaminated soil and the volume of the leachate is 1 kg: 6 L - 10 L.

[0048] In some preferred embodiments of the present invention, the conditions for the rinsing treatment include: the rinsing temperature is 25°C to 35°C; and the rinsing time is 5h to 8h.

[0049] According to the present invention, the term "water" may refer to tap water, distilled water, or deionized water, etc.

[0050] According to the present invention, the term "petroleum hydrocarbon contaminated soil" refers to soil with a petroleum hydrocarbon content greater than that specified in the "Soil Environmental Quality Standard for Construction Land Soil Pollution Risk Control (Trial)" (GB 36600-2018) for Class II construction land petroleum hydrocarbons (C1-C2). 40 Soil pollution risk screening value: 4500 mg / Kg soil.

[0051] According to the present invention, the term "alkyl glycoside" refers to an alkyl glycoside synthesized from glucose and fatty alcohol, abbreviated as APG.

[0052] According to the present invention, the term "APG0810" refers to a carbon chain with carbon atoms at C8 and C9. 10 Alkyl glycosides that are distributed throughout; the term "APG0814" refers to alkyl glycosides with carbon chains from C8 to C9. 14 Alkyl glycosides that are distributed throughout; the term "APG10" refers to alkyl glycosides with a carbon chain of C10. 10 Alkyl glycosides, also represented as C 10 APG.

[0053] The beneficial effects of this invention are at least in the following aspects:

[0054] Firstly, the concentrations and amounts of surfactants and inorganic additives are low. In the rinsing agent disclosed in Patent 1, the total concentration of biosurfactants and sodium salts is 50-1000 g / L. In the rinsing solution disclosed in Patent 2, the total concentration of anionic surfactants and inorganic additives is 20-400 g / L, and the volume ratio of alcohols to water is as high as 90-300 mL / L; the total concentration of nonionic surfactants and inorganic additives is 10-200 g / L, and the volume ratio of alcohols to water is 20-100 mL / L. However, in the rinsing solution described in this invention, the total concentration of anionic surfactants, nonionic surfactants, and inorganic additives is only 8.6-22.0 g / L. Compared with the prior art, the amount of surfactants used is reduced by 80-90%, and the amount of inorganic additives is reduced by 50-90%.

[0055] Secondly, the remediation effect is good. After using the leaching solution disclosed in this invention to leach and remediate petroleum hydrocarbon-contaminated soil, the petroleum hydrocarbon removal rate is greater than 80%, and its content is reduced from 10,000 mg / Kg to below 2,000 mg / Kg, which is significantly lower than the petroleum hydrocarbon (C1-C5) content for Class II construction land as specified in the "Soil Environmental Quality Standard for Construction Land Soil Pollution Risk Control (Trial)" (GB 36600-2018). 40 Soil pollution risk screening value: 4500 mg / Kg.

[0056] Third, the drugs selected in this invention are inexpensive, readily available, easy to prepare, and convenient to promote and use.

[0057] Fourth, the rinsing solution disclosed in this invention has low rinsing cost, good biodegradability, high safety, and no risk of secondary pollution. Detailed Implementation

[0058] The present invention will be described in detail below through embodiments, but the scope of protection of the present invention is not limited to the following description.

[0059] Unless otherwise specified in the examples, the procedures should be performed under standard conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0060] The following embodiments describe the sampling and testing of petroleum hydrocarbon-contaminated soil samples:

[0061] (1) The soil contaminated by petroleum hydrocarbons was taken from the petroleum contaminated site of a petrochemical enterprise and passed through a 10-mesh sieve to remove impurities with larger particle sizes.

[0062] (2) Determination of moisture content and petroleum hydrocarbon content in contaminated soil. The moisture content and dry matter content in contaminated soil were determined according to the Gravimetric Method for Determination of Dry Matter and Moisture in Soil (HJ613-2011); the petroleum hydrocarbon (C) content in soil and sediment was determined according to the Gravimetric Method for Determination of Dry Matter and Moisture in Soil (HJ613-2011). 10 -C 40 The determination of petroleum hydrocarbon content in contaminated soil by gas chromatography (HJ 1021-2019) is performed.

[0063] (3) Measurements showed that the dry matter content of the contaminated soil was 94.9%, the moisture content was 5.1%, and the petroleum hydrocarbon content was 9350 mg / kg. The petroleum hydrocarbon concentration was significantly higher than the Class II construction land petroleum hydrocarbon (C1-C1) standard in the "Soil Environmental Quality Standard for Construction Land Soil Pollution Risk Control" (GB36600-2018). 40 Soil pollution risk screening value: 4500 mg / Kg.

[0064] In the following examples, the alkyl glycosides used are all 50% alkyl glycoside solutions. When using them, it is necessary to calculate the equivalent: if 6 grams of alkyl glycoside are needed, then 12 grams of alkyl glycoside solution are required. That is, in this application, all figures refer to the actual amount of alkyl glycoside used, not the amount of solution used.

[0065] In the following examples, the sodium lauryl alcohol polyoxyethylene ether sulfate used is sodium lauryl alcohol polyoxyethylene ether sulfate, which is obtained through commercial channels.

[0066] Example 1

[0067] (1) Prepare sodium dodecylbenzenesulfonate solution. Weigh 2g of sodium dodecylbenzenesulfonate and prepare 1L of aqueous solution with tap water.

[0068] (2) Preparation of alkyl glycoside solution. Weigh 6g of alkyl glycoside (APG0814) and prepare 1L of aqueous solution with tap water.

[0069] (3) Preparation of rinsing solution. Weigh 1.2g of sodium metasilicate (Na2SiO3·9H2O) and place it in a beaker; measure in sequence: 48.0mL of sodium dodecylbenzenesulfonate solution, 60.0mL of alkyl glycoside solution and 12.0mL of tap water, add them to the beaker, stir and mix well to obtain 120mL of rinsing solution.

[0070] (4) Weigh 15g of petroleum hydrocarbon-contaminated soil and place it in a 250mL conical flask.

[0071] (5) Add all the leachate prepared in step (3) into the conical flask in step (4) and seal the flask. At this time, the total concentration of surfactant is 3.8 g / L, the concentration of sodium metasilicate is 10 g / L, and the ratio of contaminated soil mass to leachate volume is 1 kg: 8.0 L.

[0072] (6) Place the conical flask from step (5) in a constant temperature shaker for shaking and washing. The washing conditions are: temperature 30℃, rotation speed 180 rpm, shaking for 6 hours, followed by solid-liquid separation to obtain the washed soil.

[0073] Example 2

[0074] (1) Prepare a sodium fatty alcohol polyoxyethylene ether sulfate solution. Weigh 3g of sodium fatty alcohol polyoxyethylene ether sulfate and prepare a 1L aqueous solution with tap water.

[0075] (2) Preparation of alkyl glycoside solution. Weigh 8g of alkyl glycoside (APG1214) and prepare 1L of aqueous solution with tap water.

[0076] (3) Preparation of rinsing solution. Weigh 1.5g of sodium metasilicate (Na2SiO3·9H2O) and place it in a beaker; measure in sequence: 24.0mL of sodium fatty alcohol polyoxyethylene ether sulfate solution, 60.0mL of alkyl glycoside solution and 36.0mL of tap water, add them to the beaker, stir and mix well to obtain 120mL of rinsing solution.

[0077] (4) Weigh 15g of petroleum hydrocarbon-contaminated soil and place it in a 250mL conical flask.

[0078] (5) Take 90 mL of the leachate prepared in step (3) and add it to the conical flask in step (4), and then stopper the flask. At this time, the total concentration of surfactant is 4.6 g / L, the concentration of sodium metasilicate is 12.5 g / L, and the ratio of contaminated soil mass to leachate volume is 1 kg: 6.0 L.

[0079] (6) Place the conical flask from step (5) in a constant temperature shaker for shaking and washing. The washing conditions are: temperature 25℃, rotation speed 180 rpm, shaking for 7 hours, followed by solid-liquid separation to obtain the washed soil.

[0080] Example 3

[0081] (1) Prepare sodium dodecylbenzenesulfonate solution. Weigh 4g of sodium dodecylbenzenesulfonate and prepare a 1L aqueous solution with tap water.

[0082] (2) Preparation of alkyl glycoside solution. Weigh 10g of alkyl glycoside (C 12 APG is prepared into a 1L aqueous solution using tap water.

[0083] (3) Preparation of eluent. Weigh 1.2g of sodium silicate and place it in a beaker; measure 120.0mL of sodium dodecylbenzenesulfonate solution and 120.0mL of alkyl glycoside solution in sequence, add them to the beaker, stir and mix well to obtain 240mL of eluent.

[0084] (4) Weigh 15g of petroleum hydrocarbon-contaminated soil and place it in a 250mL conical flask.

[0085] (5) Take 150 mL of the leachate prepared in step (3) and add it to the conical flask in step (4), and then stopper the flask. At this time, the total concentration of surfactant is 7.0 g / L, the concentration of sodium silicate is 5.0 g / L, and the ratio of the mass of contaminated soil to the volume of leachate is 1 kg: 10.0 L.

[0086] (6) Place the conical flask from step (4) in a constant temperature shaker for shaking and washing. The washing conditions are: temperature 35℃, rotation speed 200 rpm, shaking for 8 hours, and then solid-liquid separation to obtain the washed soil.

[0087] Example 4

[0088] (1) Prepare a sodium fatty alcohol polyoxyethylene ether sulfate solution. Weigh 5g of sodium fatty alcohol polyoxyethylene ether sulfate and prepare a 1L aqueous solution with tap water.

[0089] (2) Preparation of alkyl glycoside solution. Weigh 6g of alkyl glycoside (APG0814) and prepare 1L of aqueous solution with tap water.

[0090] (3) Preparation of rinsing solution. Weigh 3.6g of sodium metasilicate (Na2SiO3·9H2O) and place it in a beaker; measure in sequence: 48.0mL of sodium fatty alcohol polyoxyethylene ether sulfate solution, 120.0mL of alkyl glycoside solution and 72mL of tap water, add them to the beaker, stir and mix well to obtain 240mL of rinsing solution.

[0091] (4) Weigh 15g of petroleum hydrocarbon-contaminated soil and place it in a 250mL conical flask.

[0092] (5) Take 120 mL of the leachate prepared in step (3) and add it to the conical flask in step (4), and then seal the flask. At this time, the total concentration of the surfactant is 4.0 g / L, the concentration of sodium silicate is 15.0 g / L, and the ratio of the mass of contaminated soil to the volume of leachate is 1 kg: 8.0 L.

[0093] (6) Place the conical flask from step (4) in a constant temperature shaker for shaking and washing. The washing conditions are: temperature 35℃, rotation speed 200 rpm, and shaking for 5 hours to separate the solid and liquid and obtain the washed soil.

[0094] Example 5

[0095] This embodiment basically follows the method of Example 1 for leaching petroleum hydrocarbon contaminated soil, except that sodium citrate is used instead of sodium metasilicate.

[0096] Example 6

[0097] This embodiment basically follows the method of Example 1 for leaching petroleum hydrocarbon contaminated soil, except that anhydrous sodium carbonate is used instead of sodium metasilicate.

[0098] Example 7

[0099] This embodiment basically follows the method of Example 1 for leaching petroleum hydrocarbon contaminated soil. The only difference is that the amount of sodium dodecylbenzenesulfonate solution and alkyl glycoside solution in step (3) is adjusted so that the composition of the leaching solution is: the concentration of sodium dodecylbenzenesulfonate solution is 3.0 g / L, the concentration of alkyl glycoside is 0.8 g / L, and the concentration of sodium metasilicate is 10 g / L.

[0100] Example 8

[0101] This embodiment basically follows the method of Example 1 to leach petroleum hydrocarbon contaminated soil. The only difference is that the amount of sodium dodecylbenzenesulfonate solution and alkyl glycoside solution in step (3) is adjusted so that the composition of the leachate is: the concentration of sodium dodecylbenzenesulfonate solution is 2.0 g / L, the concentration of alkyl glycoside is 1.8 g / L, and the concentration of sodium metasilicate is 10 g / L.

[0102] Example 9

[0103] This embodiment basically follows the method of Example 1 to leach petroleum hydrocarbon contaminated soil. The only difference is that the amount of sodium metasilicate in step (3) is adjusted so that the composition of the leachate is: the total concentration of surfactant is 3.8 g / L and the concentration of sodium metasilicate is 3.8 g / L.

[0104] Example 10

[0105] This embodiment basically follows the method of Example 1 to leach petroleum hydrocarbon contaminated soil. The only difference is that the amount of sodium metasilicate in step (3) is adjusted so that the composition of the leachate is: the total concentration of surfactant is 3.8 g / L and the concentration of sodium metasilicate is 16 g / L.

[0106] Comparative Example 1

[0107] This embodiment basically follows the method of Example 1 for leaching petroleum hydrocarbon contaminated soil, except that sodium metasilicate is not added in step (3).

[0108] Comparative Example 2

[0109] This embodiment basically follows the procedure of Example 1 for leaching petroleum hydrocarbon-contaminated soil, except that the leaching solution is a 3.0 g / L alkyl glycoside solution.

[0110] Comparative Example 3

[0111] This embodiment basically follows the method of Example 1 for leaching petroleum hydrocarbon contaminated soil, except that the leaching solution is a sodium dodecylbenzenesulfonate solution with a concentration of 2.0 g / L.

[0112] Comparative Example 4

[0113] This embodiment basically follows the method of Example 2 for leaching petroleum hydrocarbon contaminated soil, except that sodium metasilicate is not added in step (3).

[0114] Comparative Example 5

[0115] This embodiment basically follows the method of Example 1 for leaching petroleum hydrocarbon contaminated soil, except that the leaching solution is a 3.0 g / L sodium fatty alcohol polyoxyethylene ether sulfate solution.

[0116] Comparative Example 6

[0117] This embodiment basically follows the method of Example 3 for leaching petroleum hydrocarbon contaminated soil, except that sodium metasilicate is not added in step (3).

[0118] Test Example 1

[0119] According to the "Soil and Sediment Petroleum Hydrocarbons (C)" 10 -C 40 The petroleum hydrocarbon content in the soil after leaching remediation in each example and comparative example was determined by gas chromatography (HJ 1021-2019), and the results are shown in Table 1. The petroleum hydrocarbon removal rate (%) was calculated as: (Petroleum hydrocarbon content in the soil before remediation - Petroleum hydrocarbon content in the soil after remediation) / Petroleum hydrocarbon content in the soil before remediation × 100%.

[0120] Table 1

[0121]

[0122]

[0123] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. A method for remediating petroleum hydrocarbon-contaminated soil, comprising: Leaching treatment of petroleum hydrocarbon contaminated soil was carried out using a leaching solution. The ratio between the mass of the petroleum hydrocarbon-contaminated soil and the volume of the leachate is 1 kg: 6 L - 10 L. The conditions for the rinsing treatment include: a rinsing temperature of 25℃ to 35℃; and a rinsing time of 5 to 8 hours. The rinsing solution comprises: anionic surfactant, nonionic surfactant, inorganic additives, and water, wherein, The anionic surfactant is selected from sodium dodecylbenzene sulfonate and / or fatty alcohol polyoxyethylene ether sulfate surfactants. The nonionic surfactant is selected from at least one of alkyl glycoside surfactants; and The inorganic additives are selected from silicates and metasilicates; In the rinsing solution, the concentration of the anionic surfactant is 0.6 g / L-2.0 g / L; the concentration of the nonionic surfactant is 3.0 g / L-5.0 g / L; and the concentration of the inorganic additive is 5.0 g / L-15.0 g / L.

2. The repair method according to claim 1, characterized in that, The anionic surfactant is sodium dodecylbenzenesulfonate and / or sodium fatty alcohol polyoxyethylene ether sulfate; and / or the nonionic surfactant is selected from at least one of APG0810, APG0814, APG1214, APG0816, APG1216, APG10, APG12 and APG14; and / or the inorganic additive is sodium silicate and / or sodium metasilicate.

3. The repair method according to claim 1, characterized in that, The molecular formula of the fatty alcohol polyoxyethylene ether sulfate is RO(CH2CH2O). n SO3Na, n = 2 or 3, R is C 12 ~C 15 alkyl.

4. The repair method according to claim 1, characterized in that, The sodium lauryl alcohol polyoxyethylene ether sulfate is sodium lauryl alcohol polyoxyethylene ether sulfate.

5. The repair method according to any one of claims 1-4, characterized in that, In the rinsing solution, the mass ratio of the anionic surfactant to the nonionic surfactant is 1:(1~10); and / or the ratio of the total mass of the anionic surfactant and the nonionic surfactant to the mass of the inorganic additive is 1:(2~10).

6. The repair method according to claim 5, characterized in that, In the rinsing solution, the mass ratio of the anionic surfactant to the nonionic surfactant is 1:(2~5); and / or the ratio of the total mass of the anionic surfactant and the nonionic surfactant to the mass of the inorganic additive is 1:(2.5~5).

7. The repair method according to claim 1, characterized in that, The method for preparing the eluent includes: The anionic surfactant, the nonionic surfactant, the inorganic additive, and the water are mixed to prepare the rinsing solution.

8. The repair method according to claim 7, characterized in that, The preparation method includes: S1. Dissolve the anionic surfactant in water to obtain an anionic surfactant solution; S2. Dissolve the nonionic surfactant in water to obtain a nonionic surfactant solution; S3. The anionic surfactant solution, the nonionic surfactant solution, the inorganic additive, and optionally water are mixed to obtain the rinsing solution.

9. The repair method according to claim 7, characterized in that, The preparation method includes: 1) Dissolve the anionic surfactant in water to obtain an anionic surfactant solution; 2) Dissolve the nonionic surfactant in water to obtain a nonionic surfactant solution; 3) Mix the anionic surfactant solution, the nonionic surfactant solution, and optionally water to obtain a mixed solution; 4) The mixed solution, inorganic additives, and optionally water are mixed to obtain the rinsing solution.

10. The repair method according to claim 8 or 9, characterized in that, The concentration of the anionic surfactant in the solution is 2 g / L-5 g / L; the concentration of the nonionic surfactant in the solution is 6 g / L-10 g / L.

11. The repair method according to claim 8 or 9, characterized in that, In step S3 or step 3), the volume ratio of the anionic surfactant solution to the nonionic surfactant solution is (2-5):(3-5).

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