Petroleum-contaminated soil remediation method

Abstract

The present application relates to the field of soil remediation. Particularly disclosed is a petroleum-contaminated soil remediation method. The method comprises the following steps: thoroughly mixing a dilute hydrochloric acid solution of isooctanol polyoxyethylene ether phosphate or Triton with crushed petroleum-contaminated soil, r filtering and cleaning same, and then measuring the preliminarily cleaned contaminated soil; after the measurement shows said preliminarily cleaned contaminated soil is qualified, using a neutralizer to neutralize and remediate the preliminarily cleaned soil; and further filtering and cleaning same, and drying same to obtain cleaned remediated soil. The petroleum-contaminated soil remediation method provided by the present application can effectively remove petroleum contaminants from petroleum-contaminated soil, remove cadmium and arsenic from contaminated soil, and can also remediate soil damaged by petroleum contamination while removing contaminants. The present application is suitable for cleaning and remediation of petroleum-contaminated soil.

Description

Petroleum contaminated soil remediation methods

[0001] This patent application claims priority to Chinese patent application No. CN 202310829736.9 filed on July 7, 2023. The disclosure of the prior application is incorporated herein by reference in its entirety. Technical Field

[0002] The present application relates to the field of soil remediation, and in particular to a method for remediating petroleum-contaminated soil. Background Art

[0003] The hazards of petroleum-contaminated soil include damage to the soil's properties, damage to crops, and harm to animals and humans through the soil itself or crops. Petroleum-based substances entering the soil can alter the composition and structure of soil organic matter, causing an imbalance in the carbon, nitrogen, and phosphorus ratios. Furthermore, due to its relatively low density and strong adhesion, petroleum easily adheres to soil particles, blocking pores and affecting soil permeability. Petroleum also alters the soil's microbial community. These changes in soil properties can damage crop roots, hindering root respiration and nutrient absorption, and increasing pollutant levels in crops. Crops can exhibit symptoms such as low germination and emergence rates, delayed growth periods, decreased fruit set rates, and reduced resistance to lodging and pests and diseases, ultimately leading to reduced yields or loss of edible value due to excessive levels of pollutants. Petroleum-based aromatic hydrocarbons in contaminated soil are highly toxic. Among these, benzene, toluene, xylene, and phenols can cause nausea, headaches, and dizziness if humans and animals are exposed to them for extended periods and in high concentrations. In addition, polycyclic aromatic hydrocarbons in petroleum have strong teratogenic, mutagenic and carcinogenic effects, and can accumulate in animals and plants through the food chain, endangering their health.

[0004] Chemical remediation is an important method for remediating petroleum-contaminated soil. Currently, most of the research on petroleum-contaminated soil in my country is still in the laboratory stage. The remediation agents currently used in the laboratory have at least the following problems: (1) complex composition; (2) easy to produce secondary pollution; (3) high requirements for use conditions. Therefore, it is of great significance to develop an environmentally friendly and efficient remediation agent. Technical issues

[0005] The purpose of this application is to overcome the problems in the above-mentioned prior art and provide a low-cost, high-oil removal rate and secondary pollution-free petroleum-contaminated soil remediation method. Technical Solutions

[0006] To achieve the above objectives, the technical solutions adopted in this application are as follows:

[0007] A method for remediating petroleum-contaminated soil, the main steps of which include:

[0008] S1. Adding a surfactant solution to the petroleum-contaminated soil, mixing well, filtering, and washing to obtain remediated soil A;

[0009] S2. Detect the content of petroleum pollutants in the remediated soil A;

[0010] The testing standards refer to the petroleum pollutant residue standards in the "Soil Environmental Quality Construction Land Soil Pollution Risk Control Standards" and the "Soil Environmental Quality Agricultural Land Soil Pollution Risk Control Standards". If the test is qualified, proceed to S3; if the test is unqualified, repeat S1;

[0011] S3. Add a neutralizer to the repaired soil A for neutralization, filter, wash, and dry to obtain repaired soil B.

[0012] As an embodiment of the present application, in S1, the surfactant solution is a dilute acid solution of isooctyl polyoxyethylene ether phosphate or Triton, with a mass concentration of 1% to 9% and a pH value of 4.2 to 5.3;

[0013] Preferably, the mass concentration of the surfactant solution is 5.3%;

[0014] As an embodiment of the present application, the acid of the surfactant solution in S1 is any one of hydrochloric acid, acetic acid or oxalic acid;

[0015] Preferably, the concentration of hydrochloric acid is 19% to 33%, the concentration of acetic acid is 26% to 47%, and the concentration of oxalic acid is 21% to 39%;

[0016] Further preferably, the concentration of hydrochloric acid is 23%, the concentration of acetic acid is 34%, and the concentration of oxalic acid is 30%;

[0017] As an embodiment of the present application, in S2, the mass-to-volume ratio of the petroleum-contaminated soil to the surfactant solution is 1:3-7, where the mass unit is kg and the volume unit is L;

[0018] Preferably, in S1, the mass volume ratio of the petroleum contaminated soil to the surfactant solution is 1:5.6;

[0019] As an embodiment of the present application, in S1, the detergent used for washing is a dilute hydrochloric acid solution with a mass concentration of 6% to 17%;

[0020] Preferably, the detergent used for washing is a dilute hydrochloric acid solution with a mass concentration of 13%;

[0021] As an embodiment of the present application, in S3, the neutralizing agent used for neutralization is ammonia water with a mass concentration of 10% to 20% or a potassium bicarbonate solution with a mass concentration of 18% to 39%;

[0022] Preferably, in S3, the neutralizing agent used for neutralization is 14% ammonia water or 21% potassium bicarbonate solution;

[0023] As an embodiment of the present application, in S3, the remediation soil B is weakly alkaline, and its pH value is 7.3-8.4;

[0024] Preferably, in S3, the pH value of the remediation soil B is 7.6.

[0025] The present application also provides an application of a method for remediating petroleum-contaminated soil, which is used to clean petroleum pollutants in petroleum-contaminated soil and remediate the petroleum-contaminated soil. Beneficial effects

[0026] Due to the adoption of the above technical solution, the present application has the following beneficial effects compared with the prior art:

[0027] (1) The specific surfactant used in the petroleum-contaminated soil remediation method provided in this application can increase the fluidity of petroleum contaminants in the soil, reduce their viscosity, and cause the petroleum contaminants to fall off the soil surface, thereby effectively removing the petroleum contaminants in the petroleum-contaminated soil;

[0028] (2) The petroleum-contaminated soil remediation method provided in this application can not only clean up petroleum pollutants in the soil, but also has a good cleaning effect on heavy metal elements in the soil, such as cadmium and arsenic; by adding a dilute acid solution of isooctyl polyoxyethylene ether phosphate or Triton, the oxidation-reduction potential in the soil is increased, and the valence state of cadmium and arsenic in the soil changes, thereby forming soluble salts; the soluble salts can be dissolved in the cleaning solution and washed out of the soil, thereby achieving the removal of cadmium and arsenic in the soil;

[0029] (3) In the petroleum-contaminated soil remediation method provided in this application, during the step of neutralizing the cleaned soil, ammonia water or potassium bicarbonate can be selected according to the actual conditions of the soil to replenish the nitrogen or potassium elements lost in the soil due to pollution.

[0030] In summary, the petroleum-contaminated soil remediation method provided in this application can not only effectively remove petroleum pollutants in petroleum-contaminated soil, but also simultaneously remove cadmium and arsenic in the contaminated soil, and can also repair the soil damaged by pollution while removing pollutants.

[0031] Therefore, the petroleum-contaminated soil remediation method provided in this application is suitable for cleaning and remediating petroleum-contaminated soil. Modes for Carrying Out the Invention

[0032] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0033] Example 1

[0034] A method for remediating petroleum-contaminated soil

[0035] The petroleum contaminated soil remediation method provided in this embodiment includes the following specific implementation steps:

[0036] S1. Take 1 kg of isooctyl polyoxyethylene ether phosphate and add it to 18.87 L of 23% hydrochloric acid in batches to prepare a dilute hydrochloric acid solution of isooctyl polyoxyethylene ether phosphate with a pH value of 5.0 and a mass concentration of 5.3% for standby use; crush 1 kg of petroleum contaminated soil and add it to a stirred tank. According to the mass volume ratio of petroleum contaminated soil to surfactant solution of 1 kg: 5.6 L, 5.6 L of the prepared dilute hydrochloric acid solution of isooctyl polyoxyethylene ether phosphate was added to the stirred tank; start the stirring device to fully mix and stir the petroleum contaminated soil and the dilute hydrochloric acid solution of isooctyl polyoxyethylene ether phosphate for 10 to 24 hours, so that the petroleum contaminated soil is evenly dispersed in the dilute hydrochloric acid solution of isooctyl polyoxyethylene ether phosphate; after mixing evenly, filter with a filter device, and after solid-liquid separation, wash the solid phase with a dilute hydrochloric acid solution with a mass concentration of 13% three times. The obtained solid phase is the remediation soil A;

[0037] S2. Take a small amount of the remediated soil A obtained in S1 and send it for testing. Compare the test data of the remediated soil A sample with the standard values ​​of petroleum pollutant residues in the "Soil Environmental Quality Construction Land Soil Pollution Risk Control Standard" and the "Soil Environmental Quality Agricultural Land Soil Pollution Risk Control Standard"; if the test value is lower than the standard value, proceed to S3; if the test value is higher than the standard value, repeat S1 above;

[0038] S3. Take the qualified remediation soil A and add it to a stirring device. Add ammonia water with a mass concentration of 14% to adjust the pH value of the remediation soil A to 7.6; then filter it, separate the solid and liquid, wash the solid phase with water three times, and dry the solid phase to obtain remediation soil B.

[0039] Example 2

[0040] A method for remediating petroleum-contaminated soil

[0041] The petroleum contaminated soil remediation method provided in this embodiment includes the following specific implementation steps:

[0042] S1. Take 1 kg of Triton and add it to 100 L of 34% acetic acid in batches to prepare a dilute Triton acetic acid solution with a pH value of 4.2 and a mass concentration of 1% for standby use; crush 1 kg of petroleum-contaminated soil and add it to a stirred tank, and add 3 L of the prepared dilute Triton acetic acid solution to the stirred tank according to the mass volume ratio of petroleum-contaminated soil to surfactant solution of 1 kg:3 L; start the stirring device to fully mix and stir the petroleum-contaminated soil and the dilute Triton acetic acid solution for 10 to 24 hours, so that the petroleum-contaminated soil is evenly dispersed in the dilute Triton acetic acid solution; after mixing evenly, filter with a filter device, and after solid-liquid separation, wash the solid phase with a dilute hydrochloric acid solution with a mass concentration of 17% three times, and the resulting solid phase is remediation soil A;

[0043] S2. Take a small amount of the remediated soil A obtained in S1 and send it for testing. Compare the test data of the remediated soil A sample with the standard values ​​of petroleum pollutant residues in the "Soil Environmental Quality Construction Land Soil Pollution Risk Control Standard" and the "Soil Environmental Quality Agricultural Land Soil Pollution Risk Control Standard"; if the test value is lower than the standard value, proceed to S3; if the test value is higher than the standard value, repeat S1 above;

[0044] S3. Take the qualified remediation soil A and add it to a stirring device. Add potassium bicarbonate solution with a mass concentration of 26% to adjust the pH value of the remediation soil A to 8.4; then filter it, separate the solid and liquid, wash the solid phase with water three times, and dry the solid phase to obtain remediation soil B.

[0045] Example 3

[0046] A method for remediating petroleum-contaminated soil

[0047] The petroleum contaminated soil remediation method provided in this embodiment includes the following specific implementation steps:

[0048] S1. Take 1 kg of isooctyl alcohol polyoxyethylene ether phosphate and add it to 11.11 L of 30% oxalic acid in batches to prepare a dilute oxalic acid solution of isooctyl alcohol polyoxyethylene ether phosphate with a pH value of 5.3 and a mass concentration of 9% for standby use; crush 1 kg of petroleum contaminated soil and add it to a stirred tank. According to the mass volume ratio of petroleum contaminated soil to surfactant solution of 1 kg: 7 L, 7 L of the prepared dilute oxalic acid solution of isooctyl alcohol polyoxyethylene ether phosphate was added to the stirred tank; start the stirring device to fully mix and stir the petroleum contaminated soil and the dilute oxalic acid solution of isooctyl alcohol polyoxyethylene ether phosphate for 10 to 24 hours, so that the petroleum contaminated soil is evenly dispersed in the dilute oxalic acid solution of isooctyl alcohol polyoxyethylene ether phosphate; after mixing evenly, filter with a filter device, and after solid-liquid separation, wash the solid phase with a dilute hydrochloric acid solution with a mass concentration of 6% three times. The obtained solid phase is the remediation soil A;

[0049] S2. Take a small amount of the remediated soil A obtained in S1 and send it for testing. Compare the test data of the remediated soil A sample with the standard values ​​of petroleum pollutant residues in the "Soil Environmental Quality Construction Land Soil Pollution Risk Control Standard" and the "Soil Environmental Quality Agricultural Land Soil Pollution Risk Control Standard"; if the test value is lower than the standard value, proceed to S3; if the test value is higher than the standard value, repeat S1 above;

[0050] S3. Take the qualified remediation soil A and add it to a stirring device. Add potassium bicarbonate with a mass concentration of 20% to adjust the pH value of the remediation soil A to 8.4; then filter it, separate the solid and liquid, wash the solid phase with water three times, and dry the solid phase to obtain remediation soil B.

[0051] Example 4

[0052] A method for remediating petroleum-contaminated soil

[0053] The petroleum contaminated soil remediation method provided in this embodiment includes the following specific implementation steps:

[0054] S1. Take 1 kg of Triton and add it to 20.83 L of 20% acetic acid in batches to prepare a dilute Triton acetic acid solution with a pH of 4.4 and a mass concentration of 4.8% for standby use; crush 1 kg of petroleum-contaminated soil and add it to a stirred tank, and add 4.2 L of the prepared dilute Triton acetic acid solution to the stirred tank according to the mass volume ratio of petroleum-contaminated soil to surfactant solution of 1 kg:4.2 L; start the stirring device to fully mix and stir the petroleum-contaminated soil and the dilute Triton acetic acid solution for 10 to 24 hours, so that the petroleum-contaminated soil is evenly dispersed in the dilute Triton acetic acid solution; after mixing evenly, filter with a filter device, and after solid-liquid separation, wash the solid phase with a dilute hydrochloric acid solution with a mass concentration of 17% three times. The resulting solid phase is remediation soil A;

[0055] S2. Take a small amount of the remediated soil A obtained in S1 and send it for testing. Compare the test data of the remediated soil A sample with the standard values ​​of petroleum pollutant residues in the "Soil Environmental Quality Construction Land Soil Pollution Risk Control Standard" and the "Soil Environmental Quality Agricultural Land Soil Pollution Risk Control Standard"; if the test value is lower than the standard value, proceed to S3; if the test value is higher than the standard value, repeat S1 above;

[0056] S3. Take the qualified remediation soil A and add it to a stirring device. Add a 10% ammonia solution to adjust the pH value of the remediation soil A to 7.9; then filter it, separate the solid and liquid, wash the solid phase with water three times, and dry the solid phase to obtain remediation soil B.

[0057] Comparative Example 1

[0058] The petroleum-contaminated soil remediation method provided in this comparative example is basically the same as that in Example 1; the only difference is that sodium dodecylbenzenesulfonate is used in S1 of Comparative Example 1, and a dilute hydrochloric acid solution with a mass concentration of 5.3% is prepared as the surfactant solution; the other steps are the same as those in Example 1.

[0059] Comparative Example 2

[0060] The petroleum contaminated soil remediation method provided in this comparative example is basically the same as that in Example 1; the only difference is that a surfactant aqueous solution is prepared in S1 of Comparative Example 2, and the other steps are the same as those in Example 1.

[0061] Test example

[0062] Six soil samples were taken, each weighing 1 kg. The oil content of the six soil samples was measured to be 32268 mg / kgDW (milligrams per kilogram (dry weight)), 32134 mg / kgDW, 31468 mg / kgDW, 33257 mg / kgDW, 32089 mg / kgDW, and 31569 mg / kgDW, respectively. The six soil samples were remediated using the remediation methods of Examples 1 to 4 and Comparative Examples 1 and 2. The oil content of the remediated soil samples was measured and the oil removal rate was calculated. The oil removal rate was calculated using the following formula:

[0063]

[0064] The test results are shown in Table 1.

[0065] Table 1: Comparative test results of petroleum contaminated soil remediation methods

[0066] Repair method Original sample oil content (mg / kgDW) Repaired sample oil content (mg / kgDW) Oil removal rate μ (%) Example 1 322681040367.76 Example 2 321341181963.22 Example 3 314681186762.29 Example 4 332571189364.24 Comparative example 1 320891639448.91 Comparative example 2 315691517551.93

[0067] By further testing the pollutants in the soil before and after the sample soil remediation, it was found that the content of heavy metal arsenic and cadmium in the sample soil remediated by Examples 1 to 4 and Comparative Examples 1 and 2 also decreased. The specific test data are shown in Table 2.

[0068] Table 2: Changes in other pollutants in sample soil

[0069]

[0070] It can be seen from the above test examples that the present application can not only effectively remove petroleum pollutants in the soil, but also remove heavy metal cadmium and arsenic in the soil.

[0071] It should be noted that all the above embodiments are used to illustrate some specific implementations of the petroleum-contaminated soil remediation method provided by this application and cannot be used to limit this application. Any other changes or other equivalent replacement methods that do not deviate from the technical solution of this application are included in the scope of protection of this application.

Claims

1. A method for remediating petroleum-contaminated soil, characterized in that: include: S1. Adding a surfactant solution to the petroleum-contaminated soil, mixing evenly, filtering, and washing to obtain a repaired soil A; S2, repeat step S1 until the repaired soil A is tested to be qualified, and obtain qualified repaired soil A; S3, adding a neutralizing agent to the qualified remediation soil A for neutralization, filtering, washing, and drying to obtain remediation soil B; Wherein, the surfactant solution is a dilute acid solution of isooctyl polyoxyethylene ether phosphate or a dilute acid solution of Triton, and the pH value is 4.2-5.

3.

2. The method for remediating petroleum-contaminated soil according to claim 1, characterized in that: In S1, the mass concentration of isooctyl polyoxyethylene ether phosphate or Triton in the surfactant solution is 1% to 9%.

3. The method for remediating petroleum-contaminated soil according to claim 2, characterized in that: In S1, the mass concentration of isooctyl polyoxyethylene ether phosphate or Triton in the surfactant solution is 5.3%.

4. The method for remediating petroleum-contaminated soil according to claim 1, characterized in that: The acid in the surfactant solution is any one of hydrochloric acid, acetic acid or oxalic acid.

5. The method for remediating petroleum-contaminated soil according to claim 1, characterized in that: In S1, the mass-to-volume ratio of the petroleum-contaminated soil to the surfactant solution is 1:3-7; wherein the unit of mass is kg and the unit of volume is L.

6. The method for remediating petroleum-contaminated soil according to claim 5, characterized in that: The mass-to-volume ratio of the petroleum-contaminated soil to the surfactant solution is 1:5.6; wherein the unit of mass is kg and the unit of volume is L.

7. The method for remediating petroleum-contaminated soil according to claim 1, characterized in that: In S1, the washing liquid used for washing is a dilute hydrochloric acid solution with a mass concentration of 6% to 17%.

8. The method for remediating petroleum-contaminated soil according to claim 1, characterized in that: In S3, the neutralizing agent used for the neutralization is ammonia water or potassium bicarbonate solution.

9. The method for remediating petroleum-contaminated soil according to any one of claims 1 to 8, characterized in that: In S3, a neutralizer is added to adjust the pH value to 7.3-8.4.

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