Surfactant compositions, soil remediation agents, their preparation methods and applications, and methods for removing organic pollutants from soil

Abstract

This invention relates to the field of soil remediation, specifically to a surfactant composition, a soil remediation agent, its preparation method and application, and a method for removing organic pollutants from soil. The surfactant composition comprises a fatty acid ester alkoxysulfonate and a hydrocarbon quaternary ammonium salt, wherein the fatty acid ester alkoxysulfonate has the structural formula shown in Formula I: where R is C 10 -C 26 aliphatic hydrocarbon group, Y + It is a metal ion, R' is a C1-C4 hydrocarbon group; P includes -(C2H4O). m - and / or - (C3H6O) n - where n is any integer from 0 to 15, and m is any integer from 0 to 15. The surfactant composition of this invention, when applied to the removal of organic pollutants from soil, significantly enhances adsorption capacity and liquid film strength after mixing with gas to form foam. It expands the swept volume in heterogeneous soils, achieving the effect of removing organic pollutants from soil with a high organic matter removal rate.

Description

Technical Field

[0001] This invention relates to the field of soil remediation technology, specifically to a surfactant composition, a soil remediation agent, its preparation method and application, and a method for removing organic pollutants from soil. Background Technology

[0002] With the relocation and reconstruction of numerous industrial sites, soil organic pollution has become a major concern, and soil remediation is receiving increasing attention. Sources of organic pollutants in soil include: leaks and spills during organic chemical production processes, and the unavoidable discharge of waste gas, wastewater, and solid waste, leading to high levels of residues in the surrounding soil; additionally, pollution can also occur during the circulation and use of organic chemicals, such as pesticide overuse and improper waste disposal. Among the many pollutants, soil pollution caused by non-aqueous liquid pollutants (NAPLs) is particularly prominent. NAPLs can be classified into light-phase liquid pollutants (LNAPLs, such as petroleum hydrocarbons) and heavy-phase liquid pollutants (DNAPLs, such as polychlorinated organic compounds) based on their specific gravity relative to water. NAPLs can be trapped in the formation's porous media for extended periods, thus becoming a persistent source of pollution.

[0003] Soil remediation technologies for organic pollutants can be categorized by location into in-situ and ex-situ remediation. In-situ remediation is more economical, while ex-situ remediation carries lower environmental risk and offers more controllable treatment effects, but has a limited treatment range. Based on operating principles, they can be classified into physical, chemical, and biological remediation technologies. Physical remediation is low-cost and highly operable, but it consumes energy, damages the original soil structure and ecosystem, and is not suitable for large-scale application. Chemical remediation technologies mainly include soil leaching and chemical oxidation-reduction techniques. These technologies are effective for small areas and heavily polluted soils, but their effectiveness is limited for poorly permeable soils, and they also pose a potential risk of secondary pollution. Bioremediation is a relatively environmentally friendly remediation technology with minimal soil damage, but it requires a long remediation time and is applicable to a limited number of pollutants.

[0004] The unique amphiphilic structure of surfactants can reduce interfacial tension and solubilize the organic phase at lower concentrations, making it easier to remove organic pollutants in low-permeability areas. After surfactants generate foam, they exhibit permeability selectivity and expand the swept volume. The result of these two effects makes it possible to remove organic matter from soil pores with different permeabilities.

[0005] The literature “Remediation with surfactant foam of PCP contaminated soil” reports the use of 1% alkylphenol polyoxyethylene ether Triton X-100 to form foam for the removal of pentachlorophenol in soil. However, since Triton X-100 is a relatively weak foaming agent, only 85% of the pentachlorophenol was removed. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of existing technologies, such as the retention of organic pollutants in the pores of heterogeneous soils, difficulty in removal, easy secondary pollution during treatment, and the need for further improvement in the removal rate of organic residues. This invention provides a surfactant composition, a soil remediation agent, its preparation method and application, and a method for removing organic pollutants from soil. The soil remediation agent formed by this surfactant composition can form good foam, is green, easily degradable, and will not cause secondary pollution.

[0007] To achieve the above objectives, a first aspect of the present invention provides a surfactant composition comprising a fatty acid ester alkoxysulfonate and a hydrocarbon quaternary ammonium salt, wherein the fatty acid ester alkoxysulfonate has the structural formula shown in Formula I:

[0008]

[0009] Where R is C 10 -C 26 aliphatic hydrocarbon group, Y + It is a metal ion, R' is a C1-C4 hydrocarbon group; P includes -(C2H4O). m - and / or -(C3H6O) n - where n is any integer from 0 to 15, and m is any integer from 0 to 15.

[0010] Preferably, n and m are not both 0.

[0011] A second aspect of the present invention provides a soil remediation agent comprising the surfactant composition described in the first aspect.

[0012] A third aspect of the present invention provides a method for preparing the soil remediation agent described in the second aspect above, the method comprising: mixing the surfactant composition with, optionally, water.

[0013] The fourth aspect of this invention provides the application of the soil remediation agent described in the second aspect above in the removal of organic pollutants from soil.

[0014] The fifth aspect of the present invention provides a method for removing organic pollutants from soil, comprising injecting a gas and the soil remediation agent described in the second aspect above into the soil to displace the organic pollutants in the soil with foam.

[0015] The surfactant composition provided by this invention utilizes the synergistic interaction of fatty acid ester alkoxysulfonate and hydrocarbon quaternary ammonium salt. The fatty acid ester alkoxysulfonate can react with organic pollutants and has strong detergency, while the hydrocarbon quaternary ammonium salt is a good foaming agent. Furthermore, there is anionic and cationic electrostatic interaction between these two components. When this surfactant composition is applied to remove organic pollutants from soil, it can significantly enhance the adsorption capacity and liquid film strength after mixing with gas to form foam. It can also expand the swept volume for heterogeneous soils, thereby achieving the effect of removing organic pollution from soil. Moreover, the organic matter removal rate is high, specifically, it can remove more than 70% of organic residues, preferably more than 95%.

[0016] Moreover, the fatty acid ester alkoxysulfonate and hydrocarbon quaternary ammonium salt used in this invention are both green and easily degradable surfactants, thus avoiding secondary pollution to the formation. Detailed Implementation

[0017] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0018] The following explains some of the terms used in this invention:

[0019] “C 10 -C 26 "Aliphatic hydrocarbon group" refers to an aliphatic hydrocarbon group with a total number of carbon atoms of 10-26, including saturated or unsaturated straight-chain hydrocarbon groups, branched hydrocarbon groups, or cyclic hydrocarbon groups. It may also contain heteroatoms such as O and S, and may contain groups such as acyl, carbonyl, ether, and hydroxyl groups. Specifically, it can be a saturated or unsaturated straight-chain hydrocarbon group, branched hydrocarbon group, or cyclic hydrocarbon group with a total number of carbon atoms of 10, 11, 13, 14, 15, 16, 17, 18, 19, 20, 22, 24, or 26. For example, it can be a straight-chain C 12 H 25 -、C 15 H 29 -、C 25 H 31 -wait.

[0020] "C1-C4 hydrocarbon groups" refers to hydrocarbon groups with a total number of carbon atoms of 1-4, including saturated or unsaturated straight-chain hydrocarbon groups, branched hydrocarbon groups, or cyclic hydrocarbon groups. Specifically, they can be saturated or unsaturated straight-chain hydrocarbon groups, branched hydrocarbon groups, or cyclic hydrocarbon groups with a total number of carbon atoms of 1, 2, 3, or 4. Examples include methyl, ethyl, vinyl, n-propyl, isopropyl, propenyl, cyclopropyl, n-butyl, isobutyl, tert-butyl, etc.

[0021] The definitions of other similar groups in this article are the same as those in the previous article, differing only in the number of carbon atoms or the isomerism.

[0022] A first aspect of the present invention provides a surfactant composition comprising a fatty acid ester alkoxysulfonate and a hydrocarbon quaternary ammonium salt, wherein the fatty acid ester alkoxysulfonate has the structural formula shown in Formula I:

[0023]

[0024] Where R is C 10 -C 26 aliphatic hydrocarbon group, Y + It is a metal ion, R' is a C1-C4 hydrocarbon group; P includes -(C2H4O). m - and / or -(C3H6O) n - where n is any integer from 0 to 15, and m is any integer from 0 to 15.

[0025] The inventors of this invention have discovered that when fatty acid ester alkoxysulfonates and hydrocarbon quaternary ammonium salts are combined, they have a synergistic effect in foaming and detergency, and are particularly suitable for removing organic pollutants from soil.

[0026] Preferably, n and m are not both 0. Under this preferred scheme, the synergistic effect of fatty acid ester alkoxysulfonate and hydrocarbon quaternary ammonium salt is more significant, making it more suitable for removing soil organic pollutants and achieving a higher removal rate of organic pollutants.

[0027] In this invention, the mass ratio of the fatty acid ester alkoxysulfonate to the hydrocarbon quaternary ammonium salt can be selected within a wide range. Preferably, the mass ratio of the fatty acid ester alkoxysulfonate to the hydrocarbon quaternary ammonium salt is 1:(0.1-50), more preferably 1:(0.1-30), even more preferably 1:(0.2-20), and more preferably 1:(0.2-10). This preferred embodiment is more conducive to leveraging the synergistic effect of the fatty acid ester alkoxysulfonate and the hydrocarbon quaternary ammonium salt in foaming and detergency.

[0028] In this invention, R is preferably C. 10 -C 26 Aliphatic alkyl groups, more preferably C10, are preferred. 10 -C 20 Fatty alkyl groups.

[0029] In a preferred embodiment, R is C. 12 -C 20 The aliphatic hydrocarbon group, more preferably C 12 -C 20 Straight-chain saturated hydrocarbon groups.

[0030] In another preferred embodiment, R is C 12 -C 18 Aliphatic hydrocarbon groups.

[0031] In this invention, preferably, R' is a C1-C2 hydrocarbon group, more preferably methyl or ethyl.

[0032] In a preferred embodiment of the present invention, n is any integer from 1 to 10, and m is any integer from 0 to 12.

[0033] In another preferred embodiment of the present invention, n is any integer from 1 to 10, and m is any integer from 1 to 12, more preferably any integer from 1 to 8.

[0034] According to the present invention, preferably, P includes -(C2H4O). m - and -(C3H6O) n -

[0035] In this invention, when m and n are both present in P, the effect on -(C2H4O) is... m - and -(C3H6O) n The arrangement order of - has a wide range of options, and those skilled in the art can choose according to their needs. For example, it can be -(OC2H4)2-(OC3H6). n -(OC2H4) m-2 -or-(OC3H6)2-(OC2H4) m -(OC3H6) n-2 Preferably, P in Formula I is -(OC2H4). m -(OC3H6) n More preferably, n+m is any integer from 8 to 16.

[0036] According to the present invention, Y + As a coordinating cation, preferably, Y + It is an alkali metal ion, more preferably a sodium ion and / or a potassium ion, and even more preferably a sodium ion.

[0037] According to a preferred embodiment of the present invention, the fatty acid ester alkoxysulfonate has the structural formula shown in Formula II:

[0038]

[0039] Under the above preferred scheme, the selectable ranges of R, m, and n are the same as those mentioned above.

[0040] In this invention, the hydrocarbon-based quaternary ammonium salt refers to a quaternary ammonium salt containing a hydrocarbon group. This hydrocarbon group can be a saturated or unsaturated straight-chain hydrocarbon group, a branched hydrocarbon group, or a cyclic hydrocarbon group, and may also contain heteroatoms such as O and S, for example, acyl, carbonyl, ether, or hydroxyl groups. Those skilled in the art can adjust the groups contained in the hydrocarbon-based quaternary ammonium salt according to actual needs such as foaming performance and detergency.

[0041] In a preferred embodiment, the hydrocarbon group in the hydrocarbon-based quaternary ammonium salt is C1-C. 24 The aliphatic hydrocarbon group. This preferred embodiment further improves detergency and foaming performance.

[0042] The present invention allows for a wide range of salt types that can be selected from the hydrocarbon-based quaternary ammonium salt. Preferably, the hydrocarbon-based quaternary ammonium salt is at least one of chloride, bromide, and iodide salts.

[0043] According to a preferred embodiment of the present invention, the hydrocarbon quaternary ammonium salt is alkyl dimethyl benzyl ammonium chloride and / or alkyl trimethyl ammonium chloride having the structure shown in Formula III:

[0044]

[0045] Where R1 is C 10 -C 24 The preferred embodiment utilizes aliphatic hydrocarbon groups. This preferred embodiment further enhances the synergistic effect of fatty acid ester alkoxysulfonates and hydrocarbon quaternary ammonium salts in foaming and detergency.

[0046] More preferably, R1 is C 10 -C 18 The aliphatic hydrocarbon group, further preferably C 10 -C 18 Straight-chain saturated hydrocarbon groups.

[0047] More preferably, the alkyl group in the alkyl dimethyl benzyl ammonium chloride is C10. 10 -C 24 Aliphatic hydrocarbon groups.

[0048] In this invention, there are no restrictions on the form in which the surfactant composition exists. Each component can be stored separately or in combination. Various supply forms can also be adopted for the convenience of transportation, storage or field use, such as anhydrous solid form, aqueous solid form, aqueous paste form or aqueous solution form. The aqueous solution form includes the form of a concentrated solution prepared with water, or the form of a treatment agent prepared directly to the concentration required for the application field (e.g., field oil displacement). There are no special requirements for the water. It can be deionized water or water containing inorganic minerals. The water containing inorganic minerals can be tap water or formation water.

[0049] A second aspect of the present invention provides a soil remediation agent comprising the surfactant composition described in the first aspect. The aforementioned composition, when used to form a soil remediation agent, can effectively remediate soil, particularly effectively removing organic pollutants from the soil.

[0050] In a preferred embodiment, the soil remediation agent further contains water. Preferably, the concentration of the composition is 0.5-5 wt%, based on the total amount of the soil remediation agent.

[0051] A third aspect of the present invention provides a method for preparing the soil remediation agent described in the second aspect above, the method comprising: mixing the surfactant composition with, optionally, water.

[0052] In this invention, when the soil remediation agent contains water, there are no restrictions on the mixing method. The components in the composition can be mixed first and then mixed with water; or the components in the composition can be dissolved and mixed with water separately before being blended.

[0053] The fourth aspect of this invention provides the application of the soil remediation agent described in the second aspect above in the removal of organic pollutants from soil.

[0054] In this invention, the soil remediation agent can be used to remove any existing organic pollutants of any structure or form in the soil.

[0055] In particular, the soil remediation agent of the present invention can effectively remove heavy and light phase organic pollutants from soil, with a high removal rate and significant remediation effect. The heavy phase organic pollutants include, for example, polychlorinated organic compounds, and the light phase organic pollutants include, for example, petroleum hydrocarbons.

[0056] The fifth aspect of the present invention provides a method for removing organic pollutants from soil, comprising injecting a gas and the soil remediation agent described in the second aspect above into the soil to displace the organic pollutants in the soil with foam.

[0057] During the process of injecting gas and soil remediation agent into the soil, the gas and soil remediation agent mix to form foam, thereby achieving foam displacement.

[0058] In a preferred embodiment, the flow rate of the soil remediation agent is 0.1-50 mL / min, preferably 1-10 mL / min, and the flow rate of the gas is 0.2-200 mL / min, preferably 1-50 mL / min. In this embodiment, the soil remediation agent is preferably present in the form of an aqueous solution, and the concentration of the surfactant composition is 0.5-5 wt%, based on the total amount of the soil remediation agent.

[0059] In another preferred embodiment, the volume ratio of the soil remediation agent to the gas is 1:(1-5).

[0060] The present invention does not limit the type of gas, as long as it can achieve foam displacement of organic pollutants, such as an inert gas. Preferably, the gas is at least one of nitrogen, air and carbon dioxide.

[0061] Preferably, the method further includes: collecting the effluent obtained from the foam displacement until no organic pollutants are produced.

[0062] The present invention will be described in detail below through examples. All raw materials used in the following examples are commercially available products.

[0063] Example 1

[0064] 1. Preparation of soil remediation agent

[0065] Sodium methyl ester ethoxysulfonate (component I, having the structural formula shown in formula II) and alkyltrimethylammonium chloride (component II, having the structural formula shown in formula III) were dissolved in tap water at a mass ratio of 1:1 to prepare a 2wt% aqueous solution, thus obtaining soil remediation agent TR-1. The component ratios and the functional groups in the structural formulas of components I and II are shown in Table 1.

[0066] 2. Foam displaces organic pollutants

[0067] A planar sand-filled model with different permeabilities was constructed, with the upper layer having a permeability of 4000 mD and the lower layer having a permeability of 100 mD. After saturation with water, a mixture of cumene and tetrachloroethylene at a mass ratio of 1:1 was used as a pollutant to displace the sand-filled model until saturation. The prepared soil remediation agent and nitrogen were then injected into the sand-filled model together for further displacement. The injection rates of the soil remediation agent and nitrogen were 1.5 mL / min and 3 mL / min, respectively. Displacement continued until no pollutants flowed out, and the organic matter removal rate was calculated. The results are shown in Table 1. The formula for calculating the organic matter removal rate is: amount of pollutants displaced / amount of pollutants saturated in the sand-filled model.

[0068] Examples 2-5

[0069] The procedure was carried out according to Example 1, except that the proportions of each component shown in Table 1 and the functional groups in the structural formulas of component I and component II were used; otherwise, it was the same as in Example 1. The results are shown in Table 1.

[0070] Example 6

[0071] The procedure was carried out according to Example 1, except that component I was different, having the structural formula shown in Formula I, and R and P were shown in Table 1, with R' being C2H5 and Y being Na. + The rest is the same as in Example 1. The results are shown in Table 1.

[0072] Example 7

[0073] The procedure was carried out according to Example 1, except that R in component I is as shown in Table 1.

[0074] Example 8

[0075] The procedure was carried out according to Example 1, except that n = 1 and m = 0 in component I, as shown in Table 1.

[0076] Example 9

[0077] The procedure was carried out according to Example 1, except that component I and component II were different, as shown in Table 1.

[0078] Example 10

[0079] The procedure was carried out according to Example 1, except that component II was different, specifically using octadecyl dimethyl benzyl ammonium chloride, as shown in Table 1.

[0080] Example 11

[0081] The procedure was performed according to Example 1, except that both m and n in component I were 0. The results are shown in Table 1.

[0082] Comparative Examples 1-6

[0083] The procedure was carried out according to Example 1, except that a single component from Examples 1-3 (shown in Table 1) was used instead of the two components in Example 1 when mixed with water. The amount of the single component was the same as that of the corresponding component in the corresponding example, and everything else was the same as in Example 1. The results are shown in Table 1.

[0084] Comparative Example 7

[0085] The procedure was carried out according to Example 1, except that sodium dodecyl sulfonate (component I) and hexadecyltrimethylammonium chloride (component II) as shown in Table 1 were used instead of the two components in Example 1. All other aspects were the same as in Example 1. The results are shown in Table 1.

[0086] Comparative Example 8

[0087] The procedure was carried out according to Example 1, except that hexadecyl alcohol polyoxyethylene ether (EO10, component I) and dodecyltrimethylammonium chloride (component II) as shown in Table 1 were used instead of the two components in Example 1. All other aspects were the same as in Example 1. The results are shown in Table 1.

[0088] Table 1

[0089]

[0090]

[0091]

[0092] Unless otherwise specified, R and R1 are straight chains.

[0093] As can be seen from the results in Table 1, compared with the comparative examples, the examples using the soil remediation agent of the present invention have significantly better effects and higher organic matter removal rates. Specifically, comparing Examples 1 and Examples 6-10 shows that the scheme using the preferred structure and preferred dosage ratio of fatty acid ester alkoxysulfonate and hydrocarbon quaternary ammonium salt of the present invention achieves a higher organic matter removal rate. Comparing Examples 1 and Example 11 shows that the scheme using the preferred structure of fatty acid ester alkoxysulfonate of the present invention achieves a higher organic matter removal rate.

[0094] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A surfactant composition for soil remediation, comprising a fatty acid ester alkoxysulfonate and a hydrocarbon quaternary ammonium salt, said fatty acid ester alkoxysulfonate having the structural formula shown in Formula I: Formula I in, R is C 10 -C 26 aliphatic hydrocarbon group, Y + It is a metal ion, R' is a C1-C4 hydrocarbon group; P includes -(C2H4O). m - and -(C3H6O) n - where n is any integer from 0 to 15, and m is any integer from 0 to 15; n and m are not both 0; The mass ratio of the fatty acid ester alkoxysulfonate to the hydrocarbon quaternary ammonium salt is 1:(0.1-50).

2. The composition according to claim 1, wherein, The mass ratio of the fatty acid ester alkoxysulfonate to the hydrocarbon quaternary ammonium salt is 1:(0.1-30).

3. The composition according to claim 2, wherein, The mass ratio of the fatty acid ester alkoxysulfonate to the hydrocarbon quaternary ammonium salt is 1:(0.2-20).

4. The composition according to claim 1, wherein, n is any integer from 1 to 10, and m is any integer from 0 to 12.

5. The composition according to claim 1, wherein, R is C 12 -C 20 Aliphatic hydrocarbon groups.

6. The composition according to claim 5, wherein, R is C 12 -C 20 Straight-chain saturated hydrocarbon groups.

7. The composition according to claim 1, wherein, R' is a C1-C2 hydrocarbon group.

8. The composition according to claim 7, wherein, R' is methyl or ethyl.

9. The composition according to claim 1, wherein, P includes -(C2H4O) m - and -(C3H6O) n - where n is any integer from 1 to 10, and m is any integer from 1 to 12.

10. The composition according to claim 9, wherein, n+m is any integer from 8 to 16.

11. The composition according to claim 1, wherein, Y + It is an alkali metal ion.

12. The composition according to claim 11, wherein, Y + It is a sodium ion.

13. The composition according to any one of claims 1-12, wherein, The fatty acid ester alkoxysulfonate has the structural formula shown in Formula II: Formula II.

14. The composition according to any one of claims 1-12, wherein, The hydrocarbon group in the hydrocarbon-based quaternary ammonium salt is C1-C. 24 Aliphatic hydrocarbon groups.

15. The composition according to any one of claims 1-12, wherein, The hydrocarbon-based quaternary ammonium salt is at least one of chloride, bromide, and iodide salts.

16. The composition according to any one of claims 1-12, wherein, The hydrocarbon quaternary ammonium salt is alkyl dimethyl benzyl ammonium chloride and / or alkyl trimethyl ammonium chloride having the structural formula shown in Formula III: Formula III Where R1 is C 10 -C 24 Aliphatic hydrocarbon groups.

17. The composition according to claim 16, wherein, R1 is C 10 -C 18 Aliphatic hydrocarbon groups.

18. The composition according to claim 17, wherein, R1 is C 10 -C 18 Straight-chain saturated hydrocarbon groups.

19. The composition according to claim 16, wherein, R1 is the alkyl group of the alkyl dimethyl benzyl ammonium chloride, where the alkyl group is C. 10 -C 24 Aliphatic hydrocarbon groups.

20. A soil remediation agent comprising the surfactant composition according to any one of claims 1-19.

21. The soil remediation agent according to claim 20, wherein, The soil remediation agent also contains water, and the concentration of the surfactant composition is 0.5-5 wt% based on the total amount of the soil remediation agent.

22. A method for preparing the soil remediation agent according to claim 20 or 21, the method comprising: Mix the surfactant composition with water, optionally.

23. The application of the soil remediation agent of claim 20 or 21 in the removal of soil organic pollutants, wherein the application is in the removal of heavy phase and light phase organic pollutants in the soil.

24. A method for removing organic pollutants from soil, comprising injecting a gas and the soil remediation agent of claim 20 or 21 into the soil to displace the organic pollutants in the soil by foaming.

25. The method according to claim 24, wherein, The flow rate of the soil remediation agent is 0.1-50 mL / min, and the flow rate of the gas is 0.2-200 mL / min.

26. The method of claim 25, wherein, The flow rate of the soil remediation agent is 1-10 mL / min, and the flow rate of the gas is 1-50 mL / min.

27. The method according to any one of claims 24-26, wherein, The volume ratio of the soil remediation agent to the gas is 1:(1-5).

28. The method according to any one of claims 24-26, wherein, The gas is at least one of nitrogen, air, and carbon dioxide.

29. The method according to any one of claims 24-26, wherein, The method further includes collecting the effluent obtained from the foam displacement until no organic pollutants are produced.

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