Soil remediation composition, contaminated soil eluting agent and contaminated soil remediation method

Abstract

The invention relates to the technical field of soil remediation, and discloses a soil remediation composition, a contaminated soil eluting agent and a contaminated soil remediation method, the composition comprises a modified cyclodextrin derivative and an anionic nonionic surfactant; the modified cyclodextrin derivative has a structure as shown in a formula (I), wherein # imgabs0 # R1 is selected from C8-C22 alkyl groups; r3 and R4 are respectively and independently selected from H,-PO3M2,-PO3HM,-SO3M or-COOM, and at least one of R3 and R4 is not H; m is selected from any one of Li, Na, K and NH4; each R2 is independently selected from hydrogen or alkyl of C1-C4; m is selected from any integer of 1-10, n is selected from any integer of 1-10, z is selected from any integer of 0-9, and the sum of m, n and z is any integer of 5-11. As an eluting agent, the composition can effectively remove benzene pollutants in soil, and is environment-friendly and pollution-free.

Description

Technical Field

[0001] The present invention relates to the technical field of soil remediation, and in particular to a soil remediation composition, a contaminated soil eluent and a method for remediating contaminated soil. Background Art

[0002] Industrial wastewater discharged from organic chemical industries such as petrochemicals, coking industry, pesticides, and medicines often contains a large amount of benzene series, which has caused serious pollution to the soil near the factories. Benzene series have a high octanol-water partition coefficient and are typical hydrophobic organic pollutants. Because of their lipophilicity, persistence, and difficulty in degradation, they are easy to accumulate in the environment. In addition, benzene series are highly toxic pollutants with hazards such as "carcinogenicity, mutagenicity, and teratogenicity". They also have a strong inhibitory effect on the growth of microorganisms, posing a serious threat to human health and the ecological environment.

[0003] CN106269820A discloses a method for repairing soil contaminated by benzene series, wherein the contaminated soil is pretreated with a heptahydrated ferric sulfate solution, the pretreated soil is placed in a thermal desorption device for treatment, humic acid and polyoxyethylene sorbitan monolaurate are prepared into a solution and mixed with the soil and inserted into an electrode, and a constant voltage is applied to react for several hours. The method has a high removal rate of benzene series in the soil, but the added humic acid has a complex chemical structure and can cause secondary pollution to the soil environment. In addition, the method has a complex process and is not easy to realize industrial application.

[0004] CN111534462A discloses a composite microbial agent for treating petroleum hydrocarbons and benzene series. The contaminated soil added with the composite microbial agent can maintain a high degradation efficiency for a long time, and finally achieve complete restoration of the contaminated soil, and the removal rate of benzene series and petroleum hydrocarbons can reach more than 98%. However, the degradation efficiency of microorganisms on pollutants is limited by environmental conditions, pollutant concentrations, etc., and the treatment cycle is relatively long.

[0005] In addition, the existing eluents for remediating soil contaminated by benzene series substances have the problems of large dosage, low pollutant removal efficiency and poor removal effect. Therefore, it is necessary to develop a new eluent that has obvious removal effect on benzene series substances, is environmentally friendly and easily degradable, so as to remediate soil contaminated by benzene series substances. Summary of the invention

[0006] The purpose of the present invention is to overcome the problems of poor removal effect and low removal efficiency of benzene series in benzene series contaminated soil in the prior art, and to provide a soil remediation composition, a contaminated soil eluent and a method for remediating contaminated soil. The composition is used as a soil eluent to efficiently remove aromatic hydrocarbon pollutants in contaminated soil.

[0007] In order to achieve the above-mentioned object, the first aspect of the present invention provides a soil remediation composition, which comprises a modified cyclodextrin derivative and an anionic nonionic surfactant;

[0008] The modified cyclodextrin derivative has a structure shown in formula (I),

[0009]

[0010] Wherein, R1 is selected from C8-C 22 The alkyl group;

[0011] R3 and R4 are each independently selected from H, -PO3M2, -PO3HM, -SO3M or -COOM, and at least one of R3 and R4 is not H; M is selected from any one of Li, Na, K and NH4;

[0012] Each R2 is independently selected from hydrogen or C1-C4 alkyl;

[0013] m is selected from any integer of 1-10, n is selected from any integer of 1-10, z is selected from any integer of 0-9, and the sum of m, n and z is any integer of 5-11.

[0014] The second aspect of the present invention provides a contaminated soil eluent, which comprises the soil remediation composition described in the first aspect and a solvent.

[0015] A third aspect of the present invention provides a method for remediating contaminated soil, the method comprising: mixing a leaching agent with the contaminated soil, and then performing solid-liquid separation;

[0016] Wherein, the eluent is the contaminated soil eluent described in the second aspect.

[0017] Preferably, the pollutants in the contaminated soil include substituted or unsubstituted aromatic hydrocarbons.

[0018] The soil remediation composition provided by the present invention includes a modified cyclodextrin derivative and an anionic nonionic surfactant. The unique cavity of the cyclodextrin molecule can combine with the aromatic hydrocarbon pollutants in the benzene-contaminated soil to form a host-guest complex, thereby effectively removing the benzene pollutants in the soil. The modified cyclodextrin derivative and the anionic nonionic surfactant are combined to effectively improve the removal effect of the benzene in the contaminated soil, and the removal efficiency is high. Compared with the existing eluent, under the condition of equivalent dosage, the eluent provided by the present invention has a higher removal rate for aromatic hydrocarbon pollutants in the contaminated soil, especially for the contaminated soil containing the pollutant content higher than 1500mg / kg, the pollutant removal effect is good.

[0019] In addition, compared with existing soil leaching agents, the modified cyclodextrin derivatives and anionic nonionic surfactants used in the present invention are environmentally friendly materials, non-toxic and degradable, and will not cause secondary pollution to the soil. Based on the above main advantages, the method for repairing soil contaminated by benzene series provided by the present invention can achieve large-scale production and is easy to promote and use. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is the modified cyclodextrin derivative A1 obtained in Preparation Example 1 of the present invention 1 H NMR spectra;

[0021] Figure 2 is the modified cyclodextrin derivative A2 obtained in Preparation Example 2 of the present invention 1 H NMR spectra. DETAILED DESCRIPTION

[0022] The endpoints and any values ​​of the ranges disclosed in this article 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 each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0023] The first aspect of the present invention provides a soil remediation composition, the composition comprising a modified cyclodextrin derivative and an anionic nonionic surfactant;

[0024] The modified cyclodextrin derivative has a structure shown in formula (I),

[0025]

[0026] Wherein, R1 is selected from C8-C 22 The alkyl group;

[0027] R3 and R4 are each independently selected from H, -PO3M2, -PO3HM, -SO3M or -COOM, and at least one of R3 and R4 is not H; M is selected from any one of Li, Na, K and NH4;

[0028] Each R2 is independently selected from hydrogen or C1-C4 alkyl;

[0029] m is selected from any integer of 1-10, n is selected from any integer of 1-10, z is selected from any integer of 0-9, and the sum of m, n and z is any integer of 5-11.

[0030] The soil remediation composition provided by the present invention includes a modified cyclodextrin derivative and an anionic nonionic surfactant, which can effectively enhance the solubility of benzene series in the solution and realize the migration and removal of pollutants from the soil to the water phase. The reason is that, on the one hand, the modified cyclodextrin derivative has a unique cavity environment and can combine with hydrophobic molecules of suitable size to form a host-guest complex. On the other hand, the compounding of the modified cyclodextrin derivative and the anionic nonionic surfactant is conducive to reducing the surface tension of the aqueous solution to a greater extent and improving the solubilization effect on benzene series.

[0031] In the present invention, "C8-C 22 "Alkyl" means an alkyl group having a total of 8 to 22 carbon atoms, including C8-C 22 Straight chain alkyl, C8-C 22 The branched alkyl group may be, for example, a straight chain alkyl group or a branched alkyl group having a total number of carbon atoms of 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, or 22. For example, it may be n-octyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-hexadecyl, and the like. 16 The alkyl group of C1-C4 has a similar explanation, except that the number of carbon atoms is different. The alkyl group of C1-C4 can be, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, etc.

[0032] According to some preferred embodiments of the present invention, R1 is selected from C8-C 16 The alkyl group is preferably n-octyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl or n-hexadecyl.

[0033] According to the present invention, each R2 in formula (I) may be the same or different. Preferably, each R2 is independently selected from H, methyl or ethyl.

[0034] According to the present invention, preferably, M is selected from Na or K.

[0035] According to the present invention, preferably, m is selected from any integer of 1-7, n is selected from any integer of 1-7, z is selected from any integer of 0-6, and the sum of m, n and z is any integer of 6-8.

[0036] When R3 and R4 are each independently selected from H, -PO3M2 or -PO3HM, and at least one of R3 and R4 is not H, the modified cyclodextrin derivative can be prepared by the preparation method of cyclodextrin-based phosphate type surfactant provided in Chinese patent application 202310007991.5, and the entire content of the above patent application is cited in the present invention.

[0037] When R3 and R4 are each independently selected from H or -SO3M, and at least one of R3 and R4 is not H, the modified cyclodextrin derivative can be prepared by the preparation method of the anionic sulfate surfactant provided in Chinese patent application 202310010247.0, and the entire content of the above patent application is cited in the present invention.

[0038] When R3 and R4 are each independently selected from H or -COOM, and at least one of R3 and R4 is not H, the preparation method of the modified cyclodextrin derivative comprises:

[0039] (1) in the presence of solvent I and a catalyst, contacting and reacting a 1,2-epoxy compound represented by formula (I-1) with a cyclodextrin compound represented by formula (I-2) to obtain an intermediate;

[0040] (2) in the presence of solvent II, the intermediate, an oxidant and an alkaline substance containing the element M are mixed to carry out an oxidation reaction;

[0041]

[0042] Among them, in formula (I-1), formula (I-2), and alkaline substances,

[0043] The definitions of R1, R2, m, n, z, and M are the same as those in the previous text.

[0044] According to a preferred embodiment, in step (1), the cyclodextrin compound is provided by at least one of cyclodextrin, methyl cyclodextrin, hydroxyethyl cyclodextrin and hydroxypropyl cyclodextrin.

[0045] Preferably, the cyclodextrin is selected from at least one of α-cyclodextrin, β-cyclodextrin and γ-cyclodextrin.

[0046] More preferably, the cyclodextrin compound is at least one selected from α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, and hydroxypropyl-β-cyclodextrin.

[0047] It should be noted that the cyclodextrin compound, the 1,2-epoxy compound and the sulfonating agent in the present invention can be commercially available chemical reagents, or can be prepared by those skilled in the art according to methods known in the art.

[0048] According to a preferred embodiment, the method further comprises: in step (1), filtering and drying the product after the contact reaction between the 1,2-epoxy compound and the cyclodextrin compound. The present invention does not particularly limit the specific method of filtering and drying, and those skilled in the art can perform the filtering and drying according to known methods; as long as an intermediate can be obtained after the solvent is removed and dried to a constant weight.

[0049] Preferably, the molar ratio of the cyclodextrin compound to the 1,2-epoxy compound is 1:(1-40). More preferably, the molar ratio of the cyclodextrin compound to the 1,2-epoxy compound is 1:(1-32).

[0050] Preferably, in step (1), the solvent I is water, and the catalyst is an alkali metal hydroxide or 4-dimethylaminopyridine.

[0051] Preferably, the alkali metal hydroxide is selected from at least one of NaOH, KOH and LiOH.

[0052] Preferably, in step (1), the contact reaction conditions at least meet the following conditions: temperature of 30-100°C, time of 1-10 hours. More preferably, the contact reaction conditions at least meet the following conditions: temperature of 60-90°C, time of 3-8 hours.

[0053] Preferably, in step (1), relative to 1 mmol of the cyclodextrin compound, the amount of the solvent I is 0.1-50 mL, and the amount of the catalyst is 0.001-0.1 mmol. More preferably, relative to 1 mmol of the cyclodextrin compound, the amount of the solvent I is 1-10 mL, and the amount of the catalyst is 0.005-0.1 mmol.

[0054] In the above preparation method, part of the alkoxy groups are oxidized to carboxyl groups by the oxidation reaction in step (2). The present invention has no particular limitation on the selection of the oxidant, and conventional oxidants in the art can be used, such as potassium permanganate.

[0055] Preferably, the mass ratio of the intermediate to the oxidant is 1:(1-5), preferably 1:(1.5-2.5).

[0056] Preferably, relative to 1 g of the intermediate, the amount of the solvent II is 5-20 mL.

[0057] Preferably, in step (2), the solvent II is selected from at least one of tetrahydrofuran, 1,4-dioxane, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide and pyridine.

[0058] Preferably, in step (2), the conditions of the oxidation reaction at least meet the following conditions: temperature of 0-90° C. and time of 1-24 h.

[0059] Preferably, in step (3), the alkaline substance is selected from at least one of lithium hydroxide, sodium hydroxide, potassium hydroxide and ammonia water.

[0060] Preferably, the mass ratio of the alkaline substance containing the M element to the intermediate is (1-5):1.

[0061] In the present invention, the "anionic nonionic surfactant" has the conventional definition in the art, which refers to a surfactant composed of two hydrophilic groups and having both nonionic and anionic surface chemical properties. Surfactants with the above characteristics can be applied to the present invention. For example, the anionic nonionic surfactant can be an alkylphenol or fatty alcohol polyoxyethylene ether derivative.

[0062] According to some preferred embodiments of the present invention, the anionic nonionic surfactant is a fatty alcohol polyoxyethylene ether derivative, and the fatty alcohol polyoxyethylene ether derivative is preferably any one of fatty alcohol polyoxyethylene ether carboxylates, fatty alcohol polyoxyethylene ether sulfonates, fatty alcohol polyoxyethylene ether sulfates and fatty alcohol polyoxyethylene ether phosphates, and the metal cations in the above salts may be sodium or potassium.

[0063] Preferably, the anionic nonionic surfactant is selected from at least one of sodium fatty alcohol polyoxyethylene ether carboxylate, sodium fatty alcohol polyoxyethylene ether sulfonate, sodium fatty alcohol polyoxyethylene ether sulfate and sodium fatty alcohol polyoxyethylene ether phosphate. When the above-mentioned preferred anionic nonionic surfactant is compounded with the modified cyclodextrin derivative, the obtained soil remediation composition has a higher pollutant removal rate when used for leaching contaminated soil.

[0064] In the present invention, preferably, in the fatty alcohol polyoxyethylene ether derivative, the carbon number of the alkyl group of the fatty alcohol is 6-14, for example, the fatty alcohol can be n-hexanol, n-heptanol, n-octanol, n-nonanol, n-decanol, dodecanol, tetradecanol or isomers of the above fatty alcohols. Preferably, the carbon number of the alkyl group in the fatty alcohol is 6-12.

[0065] Preferably, in the fatty alcohol polyoxyethylene ether derivative, the polymerization degree of ethylene oxide is 3-80, preferably 6-50.

[0066] In the present invention, in the soil remediation composition, the modified cyclodextrin derivative and the anionic nonionic surfactant can be compounded in any proportion, and the removal effect of benzene series in the contaminated soil can be improved as long as the above two components are present. In order to further improve the removal rate of benzene series, preferably, in the composition, the mass ratio of the modified cyclodextrin derivative to the anionic nonionic surfactant is 60-95:5-40, preferably 75-95:5-25. For example, the mass ratio of the modified cyclodextrin derivative to the anionic nonionic surfactant can be 75:25, 78:22, 80:20, 82:28, 85:15, 88:12, 90:10, 92:8, 95:5 and other typical but non-limiting mass ratios. In the above preferred composition, it is conducive to promoting the formation of host-guest complexes between the modified cyclodextrin derivative and the benzene series in the contaminated soil, and improving the removal efficiency of the compound system for benzene series. The second aspect of the present invention provides a contaminated soil eluent, and the eluent includes the soil remediation composition and a solvent described in the first aspect.

[0067] The present invention has a wide range of choices for the solvent, and conventional inorganic or organic solvents in the art can be applied to the present invention. Preferably, the solvent is water. The eluent obtained by using water as the solvent is not only conducive to improving the solubility of benzene series in the eluent, but also non-toxic and environmentally friendly, and can avoid secondary pollution to the soil.

[0068] According to the present invention, preferably, in the eluent, the concentration of the composition is 50-200 mg / L, for example, it can be 50 mg / L, 60 mg / L, 70 mg / L, 80 mg / L, 90 mg / L, 100 mg / L, 150 mg / L, 200 mg / L and other typical but non-limiting concentration values ​​or ranges therebetween. Preferably, in the eluent, the concentration of the composition is 50-180 mg / L. Within the above preferred concentration range, it is beneficial to further enhance the elution effect of the composition formed by the modified cyclodextrin derivative and the fatty alcohol polyoxyethylene ether derivative on soil benzene pollutants.

[0069] According to some preferred embodiments of the present invention, the preparation method of the contaminated soil eluent comprises: mixing a modified cyclodextrin derivative, an anionic nonionic surfactant and a solvent. The mixing can be performed in a conventional manner in the art, and the present invention has no particular limitation thereto.

[0070] A third aspect of the present invention provides a method for remediating contaminated soil, the method comprising: mixing a leaching agent with the contaminated soil, and then performing solid-liquid separation;

[0071] Wherein, the eluent is the contaminated soil eluent described in the second aspect.

[0072] The method for remediating contaminated soil provided by the present invention has a wide range of application for the content of pollutants in the contaminated soil. In particular, compared with the prior art, the method for remediating contaminated soil provided by the present invention has a better remediation effect for contaminated soil with a high content of benzene-based pollutants.

[0073] According to some preferred embodiments of the present invention, based on the total amount of the contaminated soil, the total content of the pollutants is 800-8000 mg / kg, preferably 1000-8000 mg / kg. For the above-mentioned contaminated soil with high pollutant content, the removal effect of the elution method in the prior art is poor. Due to solubility limitations, a large amount of elution agent is usually required. However, when the dosage is equivalent, the method for repairing contaminated soil provided by the present invention has a higher pollutant removal rate and higher efficiency for contaminated soil with high pollutant content.

[0074] According to some preferred embodiments of the present invention, the mass ratio of the eluent to the contaminated soil is (2-10):1, for example, it can be 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, and preferably (3-9:1).

[0075] The method for repairing contaminated soil provided by the present invention is particularly suitable for contaminated soil containing substituted or unsubstituted aromatic hydrocarbons (benzene series), such as soil contaminated by industrial wastewater discharged from organic chemical industries such as petrochemicals, coking industries, pesticides, and medicines. The number of carbon atoms of the substituted or unsubstituted aromatic hydrocarbons is 6-10. The H on at least one carbon atom in the substituted aromatic hydrocarbons can be substituted by, for example, an alkyl, an alkenyl, a hydroxyl, etc. For example, the pollutants in the contaminated soil can include at least one of benzene, toluene, o-xylene, m-xylene, p-xylene, styrene, and phenol.

[0076] According to some preferred embodiments of the present invention, based on the total amount of the contaminated soil, the content of benzene is 100-1500 mg / kg, the content of toluene is 0-1500 mg / kg, the content of o-xylene is 30-1000 mg / kg, the content of m / p-xylene is 0-1000 mg / kg, the content of styrene is 0-1500 mg / kg, and the content of phenol is 0-1500 mg / kg.

[0077] In particular, the method for remediating contaminated soil provided by the present invention is particularly suitable for contaminated soil containing a high phenol content, especially contaminated soil containing a phenol content of more than 1000 mg / kg. Under the same eluent dosage conditions, the removal rate of phenol in contaminated soil containing a high phenol content by conventional eluents in the prior art is generally less than 60wt%, while the removal rate of phenol in the present invention is more than 90wt%.

[0078] The present invention has no particular limitation on the mixing method of the eluting agent and the contaminated soil, and the conventional soil eluting operation method and conditions in the art can be used.

[0079] According to some preferred embodiments of the present invention, the mixing is carried out under oscillation and / or stirring conditions, preferably, the rotation speed of the oscillation and / or stirring is 100-250 rpm. The above preferred mixing method is conducive to uniform mixing of the eluent and the contaminated soil, and fully exerting the removal effect of benzene series.

[0080] In the present invention, the mixing can be performed at room temperature or under heating conditions. Preferably, the mixing conditions include: a temperature of 20-70° C. and a time of 5-10 hours.

[0081] According to the present invention, the washed soil and the supernatant are obtained by the solid-liquid separation, and the solid-liquid separation can be carried out in a conventional manner in the art, and the present invention has no particular limitation thereto. For example, it can be carried out by filtering, suction filtration, centrifugation, etc.

[0082] The present invention will be described in detail below through examples.

[0083] The following preparation examples are used to illustrate the preparation of modified cyclodextrin derivatives.

[0084] Preparation Example 1

[0085] Weigh 10 mmol of β-cyclodextrin and 70 mmol of 1,2-epoxytetradecane into a reaction bottle, then add 20 mL of water, 0.05 mmol of 4-dimethylaminopyridine and a magnet. Stir the reaction at 85°C for 7 hours, stop the reaction, filter and dry to obtain intermediate I as a white solid.

[0086] Add 1 g of intermediate I and 10 mL of N,N-dimethylformamide into a three-necked flask. At the same time, weigh 2 g of sulfur trioxide pyridine complex (active SO3 content 50 wt%) and dissolve it in 5 mL of N,N-dimethylformamide. Add it into the three-necked flask and stir to react at 50 °C for 2 h. Cool to room temperature, add 10 wt% sodium hydroxide aqueous solution to adjust the pH value to 7, remove the solvent by rotary evaporation and dry to obtain the product modified cyclodextrin derivative A1 with a yield of 81%.

[0087]

[0088] The structures shown in formula (1) and formula (2) are the structures of intermediate I and modified cyclodextrin derivative A1, respectively. In formula (1) and formula (2), m is 2, n+z is 5, the sum of m, n, and z is 7, -C 12 H 25 represents n-dodecyl.

[0089] The modified cyclodextrin derivative A1 was subjected to 1 H NMR characterization (the deuterated solvent used was deuterated water), the results are as follows Figure 1 As shown, 1 H NMR (D2O): δ=0.78(-C 11 H 22 CH3),1.20-1.65(-C 11 H 22 CH3),3.28-3.85(-CH2OH,-CH-CH2-O-CH2-CHOH-C 12 H 25 ,-O-CH-CH-CH2-O-,-CHOH,),4.06(-CH-CH2-OSO3Na),4.18-4.49(-CH-CH2-OSO3Na,-CH-CH2-O-CH2-CHOH-C 12 H 25 ).

[0090] Depend on Figure 1 It can be seen that there are two broad peaks at 4.06 and 4.18-4.49 ppm. Among them, 4.06 ppm corresponds to -CH-CH2OSO3Na, and 4.18-4.49 ppm corresponds to -CH-CH2-OSO3Na and -CH-CH2-O-CH2-CHOH-C 12 H 25 , proving the successful progress of the sulfonation reaction and the existence of the sulfonation product.

[0091] Preparation Example 2

[0092] Weigh 10 mmol of α-cyclodextrin and 90 mmol of 1,2-epoxytetradecane into a reaction bottle, then add 10 mL of distilled water, 0.30 mmol of 4-dimethylaminopyridine and a magnet. Stir the reaction system at 60°C for 8 hours, stop the reaction, filter and dry to obtain a white solid intermediate II.

[0093] 1 g of intermediate II, 10 mL of N,N-dimethylformamide, and 2 g of polyphosphoric acid were added to a three-necked flask, and stirred at 60°C for 4 h; 0.15 g of water was added, and the reaction was continued at 60°C for 1 h. Subsequently, 10 wt% of potassium hydroxide was added to adjust the pH value to 7, and the solvent was removed by rotary evaporation and dried to obtain the modified cyclodextrin derivative A2 with a yield of 78%.

[0094]

[0095] The structures shown in formula (3) and (4) are the structures of intermediate II and modified cyclodextrin derivative A2, respectively. In formula (3) and (4), m is 2, n+z is 4, the sum of m, n and z is 6, -C 12 H 25 represents n-dodecyl.

[0096] The modified cyclodextrin derivative A2 was subjected to 1 H NMR characterization, the results are as follows Figure 2 shown. Figure 2 The peaks are assigned as follows:

[0097] 1 H NMR (DMSO-d6): δ=0.97(-C 11 H 22 CH3),1.35-1.48(-C 11 H 22 CH3),3.31-3.53(-CH2OH,-CH-CH2-O-CH2-CHOH-C 12 H 25 ,-O-CH-CH-CH2-O-),3.62-3.87(-CH2OH,-CH-CH-OH,-CH-CH2-O-CH2-CHOH-C 12 H 25 ,-CH-CH2-OPO3K2),4.79-4.90(-O-CH-O-).

[0098] Preparation Example 3

[0099] Weigh 10 mmol of β-cyclodextrin and 80 mmol of 1,2-epoxyoctadecane into a reaction bottle, add 20 mL of deionized water and 0.2 mmol of 4-dimethylaminopyridine, stir and react at 80° C. for 10 hours, stop the reaction, filter and dry to obtain a white intermediate III.

[0100] Add 1 g of intermediate III, 10 mL of N,N-dimethylformamide and 2 g of chlorosulfonic acid into a three-necked flask and react at 45°C for 3 h. After the reaction is completed, cool to room temperature and add 10 wt% aqueous sodium hydroxide solution to adjust the pH value to 7. After drying, obtain modified cyclodextrin derivative A3 with a yield of 74%.

[0101]

[0102] The structures shown in formula (5) and (6) are the structures of intermediate III and modified cyclodextrin derivative A3, respectively. In formula (5) and (6), m is 3, n+z is 4, the sum of m, n and z is 7, -C 16 H 33 It represents n-hexadecyl.

[0103] Preparation Example 4

[0104] Weigh 10 mmol of β-cyclodextrin and 50 mmol of 1,2-epoxydodecane into a reaction bottle, add 20 mL of deionized water and 0.1 mmol of 4-dimethylaminopyridine, react at 70° C. for 9 hours, stop the reaction, filter, and dry to obtain a white intermediate IV.

[0105] Add 1 g of intermediate IV, 10 mL of N,N-dimethylformamide, 2 g of potassium permanganate and 1 g of potassium hydroxide into a three-necked flask, react at 70°C for 2 h, cool to room temperature, filter, evaporate the filtrate to remove the solvent, add a large amount of acetone to recrystallize, and obtain the modified cyclodextrin derivative A4 with a yield of 65%.

[0106]

[0107] The structures shown in formula (7) and (8) are the structures of intermediate IV and modified cyclodextrin derivative A4, respectively. In formula (7) and (8), m is 2, n+z is 5, the sum of m, n and z is 7, -C 10 H 21 It represents n-decyl.

[0108] The following examples are used to illustrate the preparation of contaminated soil eluent and the method for remediating contaminated soil.

[0109] Example 1

[0110] Weigh 90 mg of modified cyclodextrin derivative A1 and 10 mg of sodium octanol polyoxyethylene ether (80) phosphate (purchased from Beijing Xingpu New Product Development Center), and prepare them into an aqueous solution with a concentration of 100 mg / L with distilled water to obtain a washing agent.

[0111] The contaminated soil from a dye chemical factory was used. The main pollutants were benzene (384 mg / kg), toluene (798 mg / kg), o-xylene (243 mg / kg), and m / p-xylene (98 mg / kg). Take 50 g of contaminated soil, add 150 g of the prepared eluent, and mix the contaminated soil and eluent solution at 50 ° C. Stir at a speed of 110 rpm for 10 hours. After the solid-liquid separation, the content of each pollutant in the supernatant was determined, and the removal rate was calculated. The specific results are shown in Table 1.

[0112] Removal rate (wt%) = (total amount of pollutants - content of each pollutant in the supernatant) / total amount of pollutants × 100%

[0113] Example 2

[0114] Weigh 95 mg of modified cyclodextrin derivative A2 and 5 mg of sodium tetradecyl alcohol polyoxyethylene ether (30) sulfate (purchased from Beijing Xingpu New Product Development Center), and prepare them into an aqueous solution with a concentration of 100 mg / L with distilled water to obtain a washing agent.

[0115] At a certain oil refining site, the main pollutants are toluene (1200mg / kg), o-xylene (640mg / kg), m / p-xylene (570mg / kg), and styrene (1290mg / kg). Take 50g of contaminated soil, add 350g of the prepared eluent, and mix the contaminated soil and the eluent solution at 30℃. Stir at a speed of 150 rpm for 6h. After the solid-liquid separation, the content of each pollutant in the supernatant is determined, and the removal rate is calculated. The specific results are shown in Table 1.

[0116] Example 3

[0117] Weigh 85 mg of modified cyclodextrin derivative A3 and 15 mg of sodium dodecanol polyoxyethylene ether (3) carboxylate (purchased from Beijing Xingpu New Product Development Center), and prepare them into an aqueous solution with a concentration of 100 mg / L with distilled water to obtain a washing agent.

[0118] The polluted soil from a chemical storage site was used. The main pollutants were benzene (1040 mg / kg), o-xylene (32.7 mg / kg), and styrene (2.5 mg / kg). Take 50 g of the contaminated soil, add 450 g of the prepared eluent, and mix the contaminated soil and the eluent solution at 65 ° C. Stir at a speed of 250 rpm for 8 hours. After the solid-liquid separation, the content of each pollutant in the supernatant was determined, and the removal rate was calculated. The specific results are shown in Table 1.

[0119] Example 4

[0120] Weigh 80 mg of modified cyclodextrin derivative A4 and 20 mg of sodium n-hexanol polyoxyethylene ether (50) sulfonate (purchased from Beijing Xingpu New Product Development Center), and prepare them into a 100 mg / L aqueous solution with distilled water to obtain a washing agent.

[0121] The contaminated soil from a coking plant was used. The main pollutants were benzene (228.8 mg / kg), phenol (1330 mg / kg) and toluene (2.8 mg / kg). Take 50g of the contaminated soil, add 250g of the prepared eluent, the temperature is 20℃, the contaminated soil and the eluent solution are fully mixed, and stirred at a speed of 180 rpm for 5h. After the solid-liquid separation, the content of each pollutant in the supernatant is determined, and the removal rate is calculated. The specific results are shown in Table 1.

[0122] Example 5

[0123] The method of Example 4 is followed, except that the amount of modified cyclodextrin derivative A4 used is 30 mg, the amount of sodium n-hexanol polyoxyethylene ether (50) sulfonate used is 70 mg, and distilled water is used to prepare a 100 mg / L aqueous solution to obtain an eluent.

[0124] The contaminated soil was eluted according to the method of Example 4. The results are shown in Table 1.

[0125] Example 6

[0126] The method of Example 1 is followed, except that an equal mass of sodium 1-octanol polyoxyethylene ether (120) phosphate is used to replace sodium 1-octanol polyoxyethylene ether (80) phosphate. Distilled water is used to prepare a 100 mg / L aqueous solution to obtain an eluent.

[0127] The contaminated soil was eluted according to the method of Example 1. The results are shown in Table 1.

[0128] Comparative Example 1

[0129] 100 mg of α-cyclodextrin was weighed and prepared into a 100 mg / L aqueous solution with distilled water to obtain an eluent.

[0130] Take 50g of the contaminated soil of Example 3, add 450g of the prepared eluent, and mix the contaminated soil and the eluent at 65°C, stirring at a speed of 250 rpm for 8h. After completion, separate the solid and liquid, determine the content of each pollutant in the supernatant, and calculate the removal rate. The specific results are shown in Table 1.

[0131] Comparative Example 2

[0132] Weigh 95 mg of β-cyclodextrin and 5 mg of sodium tetradecyl alcohol polyoxyethylene ether (30) sulfate (purchased from Beijing Xingpu New Product Development Center), and prepare a 100 mg / L aqueous solution with distilled water to obtain a washing agent.

[0133] Take 50g of the contaminated soil of Example 2, add 350g of the prepared eluent, and mix the contaminated soil and the eluent at a temperature of 30°C, and stir at a speed of 150 rpm for 6 hours. After the solid-liquid separation, the content of each pollutant in the supernatant is determined, and the removal rate is calculated. The specific results are shown in Table 1.

[0134] Comparative Example 3

[0135] Weigh 100 mg of sodium tetradecyl alcohol polyoxyethylene ether (30) sulfate and prepare it into a 100 mg / L aqueous solution with distilled water to obtain a washing agent.

[0136] Take 50g of the contaminated soil of Example 2, add 350g of the prepared eluent, and mix the contaminated soil and the eluent solution at a temperature of 30°C, and stir at a speed of 150 rpm for 6 hours. After the solid-liquid separation, the content of each pollutant in the supernatant is determined, and the removal rate is calculated. The specific results are shown in Table 1.

[0137] Comparative Example 4

[0138] 100 mg of sodium dodecyl sulfate (SDS) was weighed and prepared into a 100 mg / L aqueous solution with distilled water to obtain an eluent.

[0139] Take 50g of the contaminated soil of Example 4, add 250g of the prepared eluent, and mix the contaminated soil and the eluent at a temperature of 20°C, and stir at a speed of 180 rpm for 5h. After completion, separate the solid and liquid, determine the content of each pollutant in the supernatant, and calculate the removal rate. The specific results are shown in Table 1.

[0140] Table 1

[0141]

[0142] It can be seen from the results in Table 1 that the method provided by the present invention can effectively remove benzene pollutants in soil, such as benzene, toluene, xylene, phenol, styrene, etc. In particular, by comparing the examples with the comparative examples, it can be seen that the soil remediation composition or eluent provided by the present invention is more conducive to the removal of benzene, especially for high-content phenol, it has an excellent removal effect.

[0143] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A soil remediation composition, characterized in that: The composition comprises a modified cyclodextrin derivative and an anionic nonionic surfactant; The modified cyclodextrin derivative has a structure shown in formula (I), Wherein, R1 is selected from C8-C 22 The alkyl group; R3 and R4 are each independently selected from H, -PO3M2, -PO3HM, -SO3M or -COOM, and at least one of R3 and R4 is not H; M is selected from any one of Li, Na, K and NH4; Each R2 is independently selected from hydrogen or C1-C4 alkyl; m is selected from any integer of 1-10, n is selected from any integer of 1-10, z is selected from any integer of 0-9, and the sum of m, n and z is any integer of 5-11.

2. The composition according to claim 1, wherein R1 is selected from C8-C 16 Preferably, R1 is selected from C 10 -C 14 The alkyl group; and / or, each R2 is independently selected from H, methyl or ethyl; and / or, M is selected from Na or K; And / or, m is selected from any integer of 1-7, n is selected from any integer of 1-7, z is selected from any integer of 0-6, and the sum of m, n and z is any integer of 6-8.

3. The composition according to claim 1 or 2, wherein The anionic nonionic surfactant is a fatty alcohol polyoxyethylene ether derivative, and the fatty alcohol polyoxyethylene ether derivative is preferably at least one of sodium fatty alcohol polyoxyethylene ether carboxylate, sodium fatty alcohol polyoxyethylene ether sulfonate, sodium fatty alcohol polyoxyethylene ether sulfate and sodium fatty alcohol polyoxyethylene ether phosphate.

4. The composition according to claim 3, wherein In the fatty alcohol polyoxyethylene ether derivative, the carbon number of the alkyl group of the fatty alcohol is 6-14, preferably 6-12; the polymerization degree of ethylene oxide is 3-80, preferably 6-50.

5. The composition according to any one of claims 1 to 4, wherein In the composition, the mass ratio of the modified cyclodextrin derivative to the anionic nonionic surfactant is 60-95:5-40, preferably 75-95:5-25.

6. A contaminated soil cleaning agent, characterized in that: The eluent comprises the soil remediation composition according to any one of claims 1 to 5 and a solvent; Preferably, the solvent is water; Preferably, in the eluent, the concentration of the composition is 50-200 mg / L.

7. A method for remediating contaminated soil, characterized in that: The method comprises: mixing a leaching agent with the contaminated soil, and then performing solid-liquid separation; Wherein, the eluent is the contaminated soil eluent as described in claim 6.

8. The method according to claim 7, wherein: Based on the total amount of the contaminated soil, the total content of the pollutants is 800-8000 mg / kg, preferably 1000-8000 mg / kg; Preferably, the mass ratio of the eluent to the contaminated soil is (2-10):1, preferably (3-9):

1.

9. The method according to claim 8, wherein: The pollutants in the contaminated soil include substituted or unsubstituted aromatic hydrocarbons; Preferably, the substituted or unsubstituted aromatic hydrocarbon has 6 to 10 carbon atoms; Preferably, the pollutants in the contaminated soil include at least one of benzene, toluene, o-xylene, m-xylene, p-xylene, styrene and phenol; Preferably, based on the total amount of the contaminated soil, the content of benzene is 100-1500 mg / kg, the content of toluene is 0-1500 mg / kg, the content of o-xylene is 30-1000 mg / kg, the content of m / p-xylene is 0-1000 mg / kg, the content of styrene is 0-1500 mg / kg, and the content of phenol is 0-1500 mg / kg.

10. The method according to any one of claims 7 to 9, wherein: The mixing is carried out under shaking and / or stirring conditions, preferably, the shaking and / or stirring speed is 100-250 rpm; Preferably, the mixing conditions include: temperature of 20-70° C. and time of 5-10 hours.

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