Lignin-based condensed phase system, preparation method and method for repairing polluted underground water

Abstract

The invention relates to a lignin-based condensed phase system, a preparation method and a method for repairing polluted underground water. The lignin-based condensed phase system is composed of an anionic surfactant, organic amine, a nonionic surfactant and water. Based on the total mass of the lignin-based condensed phase system, the content of the anionic surfactant is 1-15 wt%, the content of the organic amine is 0.5-5 wt%, the content of the nonionic surfactant is 0.5-5 wt%, and the balance is water; the anionic surfactant is lignosulfonate; the organic amine is selected from fatty amine and / or alcohol amine, and the average molecular weight of the organic amine is 50-5000; the non-ionic surface active agent is a bio-based non-ionic surface active agent. The lignin-based condensed phase system is low in manufacturing cost and environment-friendly, can be used for repairing underground water polluted by DNAPLs, is good in repairing effect, and can avoid the situation that the underground water pollution range is expanded due to downward migration of DNAPLs.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of groundwater remediation, in particular, to a lignin-based condensed phase system, a preparation method and a method for remediation of contaminated groundwater. BACKGROUND

[0002] Heavy non-aqueous phase liquids (DNAPLs) are organic liquids with a density greater than water, such as chlorobenzene, 1,2-dichlorobenzene, 1,4-dichlorobenzene, trichloroethylene, etc., which are slightly soluble or insoluble in water, and are one of the common pollutants in the groundwater of petrochemical contaminated sites. DNAPLs have a high density and low water solubility, and during the pollution process, part of them are retained on the surface of the medium or are trapped in pores and corners to form residual phases; under the action of gravity, they continue to migrate vertically downward and accumulate on low-permeability layers or impermeable layers to form free phases, which serve as secondary pollution sources to slowly release pollutants into groundwater. At the same time, the pollution plume formed by dissolved DNAPLs will rapidly expand under the action of groundwater flow velocity, causing the pollution range to expand. After DNAPLs-contaminated groundwater enters the human body directly or indirectly, it can seriously damage the central nervous system, causing symptoms such as dizziness, nausea, excitement, convulsions and even coma in the human body, and can even cause death. In recent years, scholars have used a series of remediation technologies to remediate DNAPLs-contaminated groundwater, especially surfactant flooding remediation of DNAPLs, which is favored due to its high efficiency, low cost and construction safety. However, during the remediation process, the vertical downward migration of DNAPLs and the expansion of the pollution range can limit its application in actual remediation projects.

[0003] CN109516513A discloses a method for density regulation of heavy non-aqueous phase liquid pollutants in water, which uses double-liquid foam density regulation to remediate DNAPLs-contaminated aquifer, introduces light organic hydrocarbons such as n-dodecane, and adds an aluminum-based demulsifier to release the light organic hydrocarbons, which introduces secondary pollutants and is prone to secondary pollution.

[0004] CN115176802A discloses a lignin-based liquid-liquid condensed phase system constructed using lignin sulfonate, cationic surfactant and salt, which improves the persistence period and use efficiency of the herbicide, and increases crop yield. However, the use of cationic surfactants in this system can kill microorganisms in the groundwater system, leading to loss of ecological function, and is not suitable for groundwater remediation. In addition, the addition of salt in the condensed phase system can cause an impact on the water chemistry of the groundwater system, thereby damaging the groundwater chemical system. SUMMARY

[0005] The present disclosure aims to provide a lignin-based condensed phase system, a preparation method and a method for repairing contaminated groundwater, the lignin-based condensed phase system has low manufacturing cost and is environmentally friendly, can be used for repairing DNAPLs contaminated groundwater and has good repair effect, and can avoid the downward migration of DNAPLs to expand the contaminated range of groundwater.

[0006] To achieve the above-mentioned purpose, the present disclosure provides a lignin-based condensed phase system, which is composed of an anionic surfactant, an organic amine, a non-ionic surfactant and water;

[0007] The content of the anionic surfactant is 1-15 wt%, the content of the organic amine is 0.5-5 wt%, the content of the non-ionic surfactant is 0.5-5 wt%, and the balance is water, based on the total mass of the lignin-based condensed phase system;

[0008] The anionic surfactant is lignin sulfonate; the organic amine is selected from fatty amine and / or alcohol amine, and the average molecular weight of the organic amine is 50-5000; and the non-ionic surfactant is a bio-based non-ionic surfactant.

[0009] Optionally, the content of the anionic surfactant is 8-12 wt% of lignin sulfonate, the content of the organic amine is 1-4 wt%, the content of the non-ionic surfactant is 1-4 wt%, and the balance is water, based on the total mass of the lignin-based condensed phase system; preferably, the weight ratio of the anionic surfactant to the non-ionic surfactant is 1:0.05-0.3, preferably 1:0.08-0.25; and the weight ratio of the anionic surfactant to the organic amine is 1:0.1-0.4, preferably 1:0.2-0.4.

[0010] Optionally, the lignin sulfonate is selected from one or more of sodium lignosulfonate, calcium lignosulfonate and potassium lignosulfonate.

[0011] Optionally, the alcohol amine is selected from monoethanolamine and / or triethanolamine; and the fatty amine is selected from one or more of alkoxy polyoxyethylene amine, polyether amine, 2,2'-oxobisethylamine, polyoxyethylene diamine and ethylenediamine.

[0012] The polyether amine is selected from one or more of polyether amine T403, polyether amine D230 and polyether amine D400.

[0013] The alkoxy polyoxyethylene amine is selected from methoxy polyoxyethylene amine.

[0014] Optionally, the average molecular weight of the methoxy polyoxyethylene amine is 750-2000, preferably 1000-1500; the average molecular weight of the polyoxyethylene diamine is 200-2000, preferably 200-1000.

[0015] Optionally, the non-ionic surfactant is selected from one or more of alkyl glycoside, fatty alcohol glycoside, polyglycerol fatty acid ester and sophorolipid, preferably alkyl glycoside and / or sophorolipid, wherein the alkyl glycoside has 8-16 carbon atoms.

[0016] Optionally, the alkyl glycoside is selected from decyl glucoside; the fatty alcohol glycoside is selected from fatty alcohol polyoxyethylene glycoside; the sophorolipid is a lactone-type sophorolipid.

[0017] The second aspect of the present disclosure provides a method for preparing the lignin-based condensed phase system of the first aspect of the present disclosure, the method comprising:

[0018] The anionic surfactant, the organic amine, the non-ionic surfactant and water are mixed.

[0019] Optionally, the mixing conditions comprise: mixing under stirring, wherein the stirring rate is 200-1000 rpm; and the mixing time is 10-120 min.

[0020] The third aspect of the present disclosure provides a method for repairing contaminated groundwater using the lignin-based condensed phase system of the first aspect of the present disclosure, the method comprising: contacting the lignin-based condensed phase system of the first aspect of the present disclosure with heavy non-aqueous liquid contaminated groundwater, and collecting the displacement liquid.

[0021] Optionally, the injection amount of the lignin-based condensed phase system is 1-10 PV.

[0022] Optionally, the contaminated groundwater is contaminated with a heavy non-aqueous liquid at a concentration of 10 mg / L-130 mg / L; or,

[0023] The heavy non-aqueous liquid is in a free phase or in a residual phase.

[0024] Optionally, the heavy non-aqueous liquid comprises one or more of chlorobenzene, 1,2-dichlorobenzene, 1,4-dichlorobenzene, trichloroethylene and tetrachloroethylene.

[0025] By the technical scheme, the lignin-based condensed phase system for groundwater remediation is composed of lignin sulfonate, organic amine, bio-based non-ionic surfactant and water, and a condensed phase system is formed after mixing. The condensed phase system has a three-dimensional network microstructure like a sponge in the interior through dehydration, has rich hydrophobic microzones, can increase the drainage capacity of the condensed phase system to increase the buoyancy, can efficiently encapsulate DNAPLs pollutants, carries the DNAPLs pollutants upward, and avoids the downward migration of the pollutants to further expand the range of groundwater pollution. In addition, the complex three-dimensional network microstructure of the condensed phase system can be intertwined and pinned with the micro-nano structure of the medium interface, realizes the super-wetting state of the hydrophobic interface, more fully contacts the pollutants, and improves the remediation efficiency. The condensed phase material of the present disclosure is overall negatively charged, the surface of the groundwater medium is electronegative, and has electrostatic repulsion interaction with the surface of the groundwater medium, which can reduce the adsorption loss of the condensed phase material on the groundwater medium. The lignin-based condensed phase system of the present disclosure has low manufacturing cost and is environmentally friendly, can be used for remediation of DNAPLs contaminated groundwater, has good remediation effect, and can avoid the downward migration of DNAPLs to expand the range of groundwater pollution.

[0026] Other features and advantages of the present disclosure will be described in detail in the following detailed description section. BRIEF DESCRIPTION OF DRAWINGS

[0027] The accompanying drawings are included to provide a further understanding of the present disclosure and constitute a part of the specification, and together with the following detailed description, serve to explain the present disclosure but do not constitute a limitation thereof. In the drawings:

[0028] Figure 1 In FIG. 1, (A) is a microscopic imaging diagram of the condensed phase system of Example 1 of the present disclosure, and (B) is a microscopic imaging diagram of the preparation system of Comparative Example 1.

[0029] Figure 2 is a freeze scanning electron microscope diagram of the droplet cross section of the condensed phase system of Example 1 of the present disclosure.

[0030] Figure 3 is a contact angle diagram of the droplet of the condensed phase system of Example 1 of the present disclosure on the hydrophobic interface.

[0031] Figure 4 In FIG. 3, (A) is a photograph of an aqueous solution of 1,2-dichlorobenzene, and (B) is a photograph after the lignin-based condensed phase system prepared in Example 1 of the present disclosure enriches and separates 1,2-dichlorobenzene.

[0032] Figure 5 is a schematic diagram of an experimental device for flushing a 1,2-dichlorobenzene contaminated sand column with the lignin-based condensed phase prepared in Example 1 of the present disclosure.

[0033] Figure 6Figure of experimental results of lignin-based condensed phase prepared for Embodiment 1 of the present disclosure repairing 1,2-dichlorobenzene contaminated sand column. DETAILED DESCRIPTION

[0034] The detailed description of the present disclosure is described in detail below with reference to the accompanying drawings. It should be understood that the detailed description described herein is only used to illustrate and explain the present disclosure, and is not used to limit the present disclosure.

[0035] The present disclosure provides a lignin-based condensed phase system in the first aspect, which is composed of an anionic surfactant, an organic amine, a non-ionic surfactant and water;

[0036] The content of the anionic surfactant is 1-15wt%, the content of the organic amine is 0.5-5wt%, the content of the non-ionic surfactant is 0.5-5wt%, and the balance is water, based on the total mass of the lignin-based condensed phase system;

[0037] The anionic surfactant is lignin sulfonate; the organic amine is selected from fatty amine and / or alcohol amine, and the average molecular weight of the organic amine is 50-5000; and the non-ionic surfactant is a bio-based non-ionic surfactant.

[0038] The lignin-based condensed phase system of the present disclosure is composed of lignin sulfonate, organic amine, bio-based non-ionic surfactant and water, and forms a condensed phase system after mixing. Through dehydration, a three-dimensional network-like microstructure of sponge-like is formed inside the condensed phase system, which has abundant hydrophobic microdomains, can increase the drainage capacity of the condensed phase system to increase the buoyancy, and can efficiently encapsulate DNAPLs pollutants and carry the DNAPLs pollutants upward to avoid the downward migration of the pollutants and further expand the range of groundwater pollution. In addition, the complex three-dimensional network microstructure of the condensed phase system can interweave and pin with the micro-nano structure of the medium interface, realize the super-wetting state of the hydrophobic interface, more fully contact with the pollutants, and improve the repair efficiency. The whole condensed phase material of the present disclosure is negatively charged, the surface of the groundwater medium is electronegative, and has electrostatic repulsion with the surface of the groundwater medium, which can reduce the adsorption loss of the condensed phase material on the groundwater medium. The lignin-based condensed phase system of the present disclosure has low production cost and is environmentally friendly, can be used to repair DNAPLs contaminated groundwater, has good repair effect, and can avoid the downward migration of DNAPLs to expand the range of groundwater pollution.

[0039] According to one embodiment of the present disclosure, the content of the anionic surfactant is 8-12 wt% of lignosulfonate, the content of the organic amine is 1-4 wt%, the content of the nonionic surfactant is 1-4 wt%, and the balance is water, based on the total mass of the lignin-based condensed phase system; preferably, the weight ratio of the anionic surfactant to the nonionic surfactant is 1:0.05-0.3, preferably 1:0.08-0.25; the weight ratio of the anionic surfactant to the organic amine is 1:0.1-0.4, preferably 1:0.2-0.4. The above embodiment is conducive to improving the stability of the lignin-based condensed phase system.

[0040] According to one embodiment of the present disclosure, the lignosulfonate is selected from one or more of sodium lignosulfonate, calcium lignosulfonate and potassium lignosulfonate. The above embodiment is conducive to reducing the cost of the condensed phase system and being more environmentally friendly.

[0041] According to one embodiment of the present disclosure, the alcohol amine is selected from ethanolamine and / or triethanolamine; the fatty amine is selected from one or more of polyether amine, alkoxy polyoxyethylene amine, 2,2'-oxobisethylamine, polyoxyethylene diamine and ethylenediamine; the alkoxy polyoxyethylene amine is selected from methoxy polyoxyethylene amine; optionally, the average molecular weight of the methoxy polyoxyethylene amine is 750-2000, preferably 1000-1500; the average molecular weight of the polyoxyethylene diamine is 200-2000, preferably 200-1000; the polyether amine is selected from one or more of polyether amine T403, polyether amine D230 and polyether amine D400. The above embodiment is conducive to forming the condensed phase system, forming a three-dimensional network-like microstructure like a sponge inside the system, forming a hydrophobic microregion, increasing the drainage capacity of the condensed phase system to increase the buoyancy, and efficiently encapsulating DNAPLs pollutants.

[0042] According to one embodiment of the present disclosure, the nonionic surfactant is selected from one or more of alkyl glycoside with a carbon atom number of 8-16, fatty alcohol glycoside, polyglycerol fatty acid ester and sophorolipid, preferably alkyl glycoside and / or sophorolipid. Further, the alkyl glycoside can be selected from decyl glucoside; the fatty alcohol glycoside can be selected from fatty alcohol polyoxyethylene glycoside; and the sophorolipid is a lactone-type sophorolipid. The above embodiment can avoid secondary pollution to the environment during the repair process.

[0043] The second aspect of the present disclosure provides a method for preparing the lignin-based condensed phase system of the first aspect of the present disclosure, the method comprising:

[0044] The anionic surfactant, the organic amine, the nonionic surfactant and water are mixed.

[0045] The lignin-based condensed phase system of the present disclosure uses lignin sulfonate, a natural renewable and abundant resource, a bio-based non-ionic surfactant, an organic amine and water, is low in cost, friendly to the environment, does not damage the groundwater system, and forms a condensed phase system with rich hydrophobic micro-regions, high enrichment separation, strong wetting and spreading performance and upward transport performance.

[0046] According to an embodiment of the present disclosure, the mixing conditions include: mixing under stirring, the stirring rate is 200-1000 rpm; and the mixing time is 10-120 min.

[0047] The third aspect of the present disclosure provides a method for repairing contaminated groundwater using the lignin-based condensed phase system of the first aspect of the present disclosure, the method comprising: contacting the lignin-based condensed phase system of the first aspect of the present disclosure with heavy non-aqueous phase liquid contaminated groundwater, and collecting the displacement liquid.

[0048] According to an embodiment of the present disclosure, the injection amount of the lignin-based condensed phase system is 1-10 PV.

[0049] According to an embodiment of the present disclosure, the contamination concentration of the heavy non-aqueous phase liquid contaminated groundwater is 10 mg / L-130 mg / L; or the heavy non-aqueous phase liquid is a free phase or a residual phase. In the present disclosure, the contamination concentration of the heavy non-aqueous phase liquid contaminated groundwater refers to the concentration of dissolved phase pollutants, which refers to a small part of the pollutants as solutes entering the groundwater and continuously migrating with the groundwater flow to form a pollution plume when the pollutants migrate below the groundwater surface. This part of the pollutants is the dissolved phase pollutants; the free phase refers to the flowable single pure phase pollutants that exceed the solubility of the groundwater; the residual phase refers to the single pure phase pollutants adhered to the underground medium. The lignin-based condensed phase system of the present disclosure can be used to repair groundwater contaminated by dissolved phase pollutants, and can also be used for groundwater contaminated by non-dissolved phase pollutants.

[0050] According to an embodiment of the present disclosure, the heavy non-aqueous phase liquid comprises one or more of chlorobenzene, 1,2-dichlorobenzene, 1,4-dichlorobenzene, trichloroethylene and tetrachloroethylene.

[0051] The present disclosure will be further described by examples, but the present disclosure is not limited in any way by the examples. Unless otherwise specified, the raw materials used in the examples and comparative examples of the present disclosure are purchased through commercial channels.

[0052] Example 1

[0053] Take 10 g of lignin sulfonate sodium (anionic surfactant, purchased from ALADDIN company, item number S140863-500 g), 3 g of polyoxyethylene diamine (organic amine, CAS number 24991-53-5, average molecular weight 400), 1 g of decyl glucoside (nonionic surfactant, CAS number 68515-73-1) and 86 g of water, mix them uniformly, and obtain a lignin-based condensed phase system by stirring at 350 rpm at 25°C for 20 min. The specific weight content of each component is shown in Table 1.

[0054] Take the droplets of the condensed phase system and place them on a glass slide, and observe them using an optical microscope (40x objective lens). The optical micrograph is shown in Figure 1 As shown in FIG. 1A, a large number of micron-sized droplets can be seen in the field of view, indicating that the system has formed a liquid-liquid condensed phase.

[0055] In-situ micro-imaging of the cross-section of the droplets was performed using a freeze scanning electron microscope. The in-situ freeze scanning electron micrograph is shown in Figure 2 As shown in FIG. 2, a porous three-dimensional network microstructure is formed inside the condensed phase droplets, and there are many hydrophobic micro-regions.

[0056] Place the droplets of the liquid-liquid condensed phase system on paraffin (hydrophobic interface), and test the contact angle using a contact angle meter. As shown in Figure 3 This indicates that the liquid-liquid condensed phase system can achieve super-wetting on the hydrophobic interface, and can more fully contact the pollutants.

[0057] The lignin-based condensed phase system of Example 1 was used to treat an aqueous solution of 1,2-dichlorobenzene (as shown in Figure 4 A), 2 g of the lignin-based condensed phase system was placed in 6 mL of aqueous solution (containing 0.2 mL of pure phase 1,2-dichlorobenzene), and stirred at a speed of 500 rpm for 10 min, then left to stand. After spontaneous phase separation, as shown in Figure 4 B, layer I is the condensed phase enriched with 1,2-dichlorobenzene, and layer II is the dilute phase mainly existing in the aqueous solution.

[0058] Example 2

[0059] Take 12 g of calcium lignosulfonate (anionic surfactant, product number 8061-52-7), 3 g of 2,2'-oxobisethylamine (organic amine, molecular weight 104, CAS number 2752-17-2), 1 g of lactone sophorolipid (nonionic surfactant, CAS number 148409-20-5) and 84 g of water, mix them uniformly, and obtain a lignin-based condensed phase system by stirring at 400 rpm at room temperature for 30 min.

[0060] The optical microscopic imaging photo, in-situ freeze scanning electron microscopy photo of the liquid-liquid coacervate phase system are basically the same as those of Example 1, the inside of the coacervate phase droplet forms a porous three-dimensional network microstructure, and has more hydrophobic microareas.

[0061] Example 3

[0062] 8 g of potassium lignosulfonate (anionic surfactant), 2 g of polyoxyethylene diamine (organic amine, average molecular weight 1000), 2 g of fatty alcohol polyoxyethylene ether glucoside (nonionic surfactant, product number 1654752-70-1) and 88 g of water are uniformly mixed, and stirred at 200 rpm for 40 min at room temperature to obtain a lignin-based coacervate phase system.

[0063] The optical microscopic imaging photo, in-situ freeze scanning electron microscopy photo of the liquid-liquid coacervate phase system are basically the same as those of Example 1, the inside of the coacervate phase droplet forms a porous three-dimensional network microstructure, and has more hydrophobic microareas.

[0064] Example 4

[0065] The method is the same as that of Example 1, except that the sodium lignosulfonate (anionic surfactant) used is 5.5 g, and the decyl glucoside (nonionic surfactant, CAS number 68515-73-1) used is 5.5 g.

[0066] Example 5

[0067] The method is the same as that of Example 1, except that the sodium lignosulfonate (anionic surfactant) used is 7.2 g, and the polyoxyethylene diamine (organic amine, CAS number 24991-53-5, average molecular weight 400) used is 5.5 g.

[0068] Comparative Example 1

[0069] 8 g of potassium lignosulfonate (anionic surfactant), 2 g of decyl glucoside (nonionic surfactant, CAS number 68515-73-1) and 90 g of water are uniformly mixed, and stirred at 200 rpm for 40 min at room temperature to prepare a system.

[0070] The droplets of the system are placed on a glass slide, and observed using an optical microscope (40x objective lens), and the optical microscopic imaging photo is as shown in Figure 1 B, it can be seen that no coacervate phase droplets are formed in the field of view, indicating that the liquid-liquid coacervate phase system of the present disclosure is not formed.

[0071] Comparative Example 2

[0072] 4g polyoxyethylene diamine (organic amine, average molecular weight 400), 2g decyl glucoside (nonionic surfactant, CAS No. 68515-73-1) and 94g water were mixed uniformly to prepare a complex system, which was stirred at 350 rpm for 20 min at room temperature.

[0073] The optical microscopic imaging of the complex system was basically the same as that of Comparative Example 1, indicating that the liquid-liquid condensed phase system of the present disclosure was not formed.

[0074] Comparative Example 3

[0075] 12g sodium lignosulfonate, 3g polyoxyethylene diamine (organic amine, average molecular weight 6000), 1g lactone sophorolipid and 84g water were mixed uniformly to prepare a complex system, which was stirred at 350 rpm for 20 min at room temperature.

[0076] The optical microscopic imaging of the complex system was basically the same as that of Comparative Example 1, indicating that the liquid-liquid condensed phase system of the present disclosure was not formed.

[0077] Comparative Example 4

[0078] 18g calcium lignosulfonate, 7g 2,2' oxybisethylamine, 6g lactone sophorolipid and 69g water were mixed uniformly to prepare a complex system, which was stirred at 400 rpm for 30 min at room temperature.

[0079] The optical microscopic imaging of the complex system was basically the same as that of Comparative Example 1, indicating that the liquid-liquid condensed phase system of the present disclosure was not formed.

[0080] Table 1

[0081]

[0082]

[0083] Test Example

[0084] 10g of the system prepared in Examples 1-5 and Comparative Examples 1-4 was mixed with 2g of 1,2-dichlorobenzene contaminated quartz sand (1,2-dichlorobenzene mass percentage of 10wt%). After spontaneous phase separation, the displacement liquid was collected, and the concentration of 1,2-dichlorobenzene in the displacement liquid was determined according to the water quality chlorobenzene compound determination gas chromatography method (HJ 621-2011). The specific results are shown in Table 2.

[0085] Taking the solubility of 1,2-dichlorobenzene at 20℃ as 130mg / L as a benchmark, the calculation formula of the remediation efficiency is:

[0086] Remediation efficiency = (concentration of 1,2-dichlorobenzene in displacement liquid - benchmark concentration) / benchmark concentration.

[0087] Table 2

[0088]

[0089]

[0090] According to the data in Table 2, when the liquid-liquid condensed phase systems of Examples 1-5 are used to repair the 1,2-dichlorobenzene contaminated quartz sand, the large number of hydrophobic microzones in the condensed phase can enhance the solubilization capacity of the pollutants, and the concentration of the pollutants in the collected displacement liquid is high, and the repair effect is good. The systems of Comparative Examples 1-4, wherein the complex system of Comparative Example 1 does not contain an organic amine, the system of Comparative Example 2 does not contain an anionic surfactant lignosulfonate, the organic amine used in Comparative Example 3 has a molecular weight not within the range of the present disclosure, and the content of each component in Comparative Example 4 is not within the content range of the present disclosure, cannot obtain a condensed phase system, and have poor solubilization capacity for pollutants and poor repair effect.

[0091] As can be seen from the comparison of Examples 4 and 5 with Example 1, within the weight ratio of the anionic surfactant to the nonionic surfactant and the weight ratio of the anionic surfactant to the organic amine, the liquid-liquid condensed phase system obtained has better solubilization capacity for pollutants and better repair effect.

[0092] Application Example

[0093] As shown in the experimental device schematic diagram Figure 5 , the lignin-based condensed phase system prepared in Example 1 was used to flush the simulated sand column (inner diameter 3 cm, length 30 cm) contaminated with 1,2-dichlorobenzene (stained with oil red), and after flushing 2 PV (pore volume), the results are shown in Figure 6 , the red color of the sand column was completely removed, indicating that the lignin-based condensed phase system of the present disclosure can be used to repair 1,2-dichlorobenzene contaminated groundwater, and has good repair effect.

[0094] The preferred embodiments of the present disclosure are described in detail above with reference to the accompanying drawings, but the present disclosure is not limited to the specific details in the above-described embodiments. Within the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all belong to the protection scope of the present disclosure.

[0095] In addition, it should be noted that each specific technical feature described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, various possible combinations are not described again in the present disclosure.

[0096] In addition, various different embodiments of the present disclosure can also be combined in any manner, as long as they do not deviate from the idea of the present disclosure, and they should also be considered as disclosed by the present disclosure.

Claims

1. A lignin-based condensed phase system, characterized in that, The lignin-based condensed phase system is composed of anionic surfactants, organic amines, nonionic surfactants, and water. Based on the total mass of the lignin-based condensed phase system, the content of the anionic surfactant is 1-15 wt%, the content of the organic amine is 0.5-5 wt%, the content of the nonionic surfactant is 0.5-5 wt%, and the balance is water; The anionic surfactant is a lignin sulfonate; the organic amine is selected from fatty amines and / or alcoholic amines, and the average molecular weight of the organic amine is 50 to 5000; the nonionic surfactant is a bio-based nonionic surfactant.

2. The lignin-based condensed phase system according to claim 1, wherein, Based on the total mass of the lignin-based condensed phase system, the anionic surfactant comprises 8-12 wt% lignin sulfonate, the organic amine comprises 1-4 wt%, the nonionic surfactant comprises 1-4 wt%, and the balance is water; preferably, the weight ratio of the anionic surfactant to the nonionic surfactant is 1: The ratio of anionic surfactant to organic amine is 0.05 to 0.3, preferably 1:0.08 to 0.25; the weight ratio of the anionic surfactant to organic amine is 1:0.1 to 0.4, preferably 1:0.2 to 0.

4.

3. The lignin-based condensed phase system according to claim 1, wherein, The lignin sulfonate is selected from one or more of sodium lignin sulfonate, calcium lignin sulfonate, and potassium lignin sulfonate.

4. The lignin-based condensed phase system according to claim 1, wherein, The alkanolamine is selected from ethanolamine and / or triethanolamine; the fatty amine is selected from one or more of alkoxy polyoxyethylene amine, polyether amine, 2,2'-oxodiethylamine, polyoxyethylene diamine and ethylenediamine. The polyetheramine is selected from one or more of polyetheramine T403, polyetheramine D230 and polyetheramine D400; The alkoxy polyoxyethylene amine is selected from methoxy polyoxyethylene amine; Optionally, the average molecular weight of the methoxy polyoxyethylene amine is 750-2000, preferably 1000-1500; the average molecular weight of the polyoxyethylene diamine is 200-2000, preferably 200-1000.

5. The lignin-based condensed phase system according to claim 1, wherein, The nonionic surfactant is selected from one or more of alkyl glycosides, fatty alcohol glycosides, polyglycerol fatty acid esters and sophorolipids with 8 to 16 carbon atoms, preferably alkyl glycosides and / or sophorolipids; Optionally, the alkyl glycoside is selected from decyl glucoside; the fatty alcohol glycoside is selected from fatty alcohol polyoxyethylene ether glucoside; and the sophorolipid is a lactone type sophorolipid.

6. A method for preparing the lignin-based condensed phase system according to any one of claims 1 to 5, characterized in that, The method includes: The anionic surfactant, the organic amine, the nonionic surfactant, and water are mixed.

7. The method according to claim 6, wherein, The mixing conditions include: the mixing is carried out under stirring conditions, the stirring rate is 200-1000 rpm, and the mixing time is 10-120 min.

8. A method for remediating contaminated groundwater using a lignin-based condensed phase system, characterized in that, The method includes: contacting the lignin-based condensed phase system according to any one of claims 1 to 5 with heavy non-aqueous liquid-contaminated groundwater, and collecting the displacement fluid.

9. The method according to claim 8, wherein, The injection amount of the lignin-based condensed phase system is 1 to 10 PV.

10. The method according to claim 8, wherein, The concentration of the heavy non-aqueous liquid contaminating the groundwater is 10 mg / L to 130 mg / L; or, The heavy non-aqueous liquid is either a free phase or a residual phase; Optionally, the heavy non-aqueous phase liquid includes one or more of chlorobenzene, 1,2-dichlorobenzene, 1,4-dichlorobenzene, trichloroethylene, and tetrachloroethylene.

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