A method for preparing a chlorinated hydrocarbon contaminant remediation agent and a chlorinated hydrocarbon contaminant remediation agent and uses thereof

Abstract

The present application relates to chlorinated hydrocarbon pollutant remediation technical field, specifically relates to a kind of preparation chlorinated hydrocarbon pollutant remediation reagent and chlorinated hydrocarbon pollutant remediation reagent and its application.The method includes the following steps: (1) component A, surfactant, iron source and carbon-containing adsorbent are carried out first ball milling;(2) the material obtained in step (1) is carried out second ball milling with first portion water;(3) the material obtained in step (2) is carried out third ball milling with second portion water;Wherein, the component A is vegetable oil and / or fatty acid;The weight ratio of the amount of first portion water and second portion water is 1: (3-5).The chlorinated hydrocarbon pollutant remediation reagent prepared by the method of the present application is a kind of reagent with chemical reduction and biological stimulation microbial degradation chlorinated hydrocarbon, with excellent remediation performance and stability, after injection into underground, still can keep oil-water emulsion oil-in-water phase state for a long time.

Description

Technical Field

[0001] This invention relates to the field of chlorinated hydrocarbon remediation technology, specifically to a method for preparing chlorinated hydrocarbon remediation agents and the chlorinated hydrocarbon remediation agents and their applications. Background Technology

[0002] Currently, groundwater pollution is widespread, especially in shallow groundwater, and the degree of pollution is constantly worsening, with the affected area expanding daily. Halogenated hydrocarbons are among the most common organic pollutants. In urban groundwater samples, halogenated hydrocarbons are the most frequently detected organic pollutants. Among the halogenated hydrocarbon organic pollutants in groundwater, trichloroethylene (TCE), carbon tetrachloride (CT), and tetrachloroethylene (PCE) are the most common.

[0003] Chlorinated organic solvents are widely used in industrial manufacturing processes such as degreasing, cleaning of electronic components, and dry cleaning. Due to improper management and disposal, chlorinated organic solvents often leak out and become common heavy non-aqueous phase liquids (DNAPL) pollutants in groundwater. Because heavy non-aqueous phase liquids are denser than water and immiscible or only slightly soluble in water, they form an independent liquid phase after entering the groundwater layer. Once a chlorinated hydrocarbon leak occurs, it may be exposed to the environment through drinking water and other routes, causing serious harm to the health of nearby residents.

[0004] Traditional remediation technologies include groundwater extraction and treatment, in-situ thermal desorption, surfactant leaching, and zero-valent iron chemical reduction. However, these technologies all have various problems, the most common being tailing and rebound issues during the remediation process. To address these pollution problems, many studies have focused on chlorinated hydrocarbons as the target pollutant, developing in-situ biostimulation remediation technologies for treating DNAPL-contaminated groundwater. This technology is relatively environmentally friendly and rapid. Its application in in-situ degradation of environmental pollutants mainly involves providing biodegradable organic matrix components to promote the growth of indigenous dechlorination microorganisms, thereby assisting microbial decomposition of pollutants. Therefore, compared to physical and chemical remediation methods, it can relatively reduce remediation costs, is easy to operate, and is more readily accepted by the public. Furthermore, as an in-situ remediation technology, in-situ biostimulation remediation causes minimal site disturbance, provides long-term effectiveness with a single injection, and effectively solves the tailing and rebound problems encountered during the remediation process. Since no off-site disposal is required, it avoids the generation of wastewater and solid waste, and eliminates concerns about secondary environmental damage such as chemical precipitation and the production of large amounts of harmful sludge.

[0005] Patent application CN114477474A discloses an in-situ remediation agent, preparation method, and application for groundwater contamination with chlorinated hydrocarbons. The remediation agent includes zero-valent iron powder, biochar, biocarbon source, emulsifier, stabilizer, and water. The biocarbon source includes short-acting, medium-acting, and long-acting carbon sources. The weight percentages of each component are as follows: zero-valent iron powder 20-45%, biochar 8-15%, biocarbon source 15-35%, emulsifier 1-3%, stabilizer 0.1-0.5%, and water 15-30%. By adding reusable oil and emulsifier to water and stirring at low speed to fully emulsify the reusable oil and emulsifier, zero-valent iron powder, biochar, and stabilizer are added sequentially and stirred to mix evenly. Industrial syrup and straw powder are then added and mixed at a stirring speed of 2000 r / min for 10-20 min to obtain a remediation agent slurry. The remediation agent is then injected under high pressure into the groundwater aquifer contaminated with halogenated hydrocarbons to achieve in-situ water remediation. This method is highly efficient, low-cost, and beneficial for engineering applications of groundwater contaminated with chlorinated hydrocarbons.

[0006] Patent application CN108675435A discloses a nanoemulsified carbon source with low aquifer permeability loss in groundwater remediation and its preparation method. Specifically, the nanoemulsified carbon source is composed of water, edible vegetable oil, and food-grade emulsifier; the mass ratio of food-grade emulsifier to edible vegetable oil is 1:(1-2); the food-grade emulsifier is a mixture of Tween-80 and Span-80, with a mass ratio of Tween-80 to Span-80 of 1:(0.2-0.5); the internal phase content is 5-35%. The preparation method involves mixing the components in the specified proportions, stirring for 5-15 minutes, followed by ultrasonication for 15-25 minutes, heating to 55-70℃ and holding for 5-10 minutes, and then allowing natural cooling. This nanoemulsified carbon source has small particle size, low viscosity, and high stability, making it easy to inject into groundwater and effectively alleviating permeability loss and blockage in porous aquifer media.

[0007] Patent application CN109534517A discloses an emulsified vegetable oil, its preparation method, and its application. The emulsified vegetable oil comprises the following components by weight percentage: 45%-75% edible vegetable oil, 2%-12% surfactant, and 20%-45% water; it also optionally includes a common substrate and / or a pH adjuster. The preparation method of the emulsified vegetable oil includes steps such as mixing and dissolving soluble substrates and mixing and stirring oil and water. The application method of the emulsified vegetable oil includes steps such as well construction, preparation of the emulsified oil working solution, assessment of indigenous microbial activity, and injection of the emulsified oil working solution, thereby achieving the remediation of groundwater contaminated with chlorinated organic compounds to meet standards. The emulsified vegetable oil prepared by this invention has a rapid onset of action and a stable and long-lasting effect after injection; a single injection can provide continuous effectiveness for 3 to 5 years, eliminating the need for long-term continuous addition. Summary of the Invention

[0008] The purpose of this invention is to overcome the problems of low stability of emulsions prepared by mechanical stirring, difficulty in controlling the particle size of the internal phase, and insufficient performance of reducing components in the existing technology, and to provide a method for preparing chlorinated hydrocarbon pollutant remediation agents and the chlorinated hydrocarbon pollutant remediation agents and their applications.

[0009] To achieve the above objectives, the present invention provides a method for preparing a remediation agent for chlorinated hydrocarbon pollutants, the method comprising the following steps:

[0010] (1) Component A, surfactant, iron source and carbon adsorbent are subjected to a first ball milling;

[0011] (2) The material obtained in step (1) is subjected to a second ball milling with the first part of water;

[0012] (3) The material obtained in step (2) is subjected to a third ball milling with the second part of water;

[0013] Component A is vegetable oil and / or fatty acids;

[0014] The weight ratio of the first portion of water to the second portion of water is 1:(3-5).

[0015] Preferably, the total weight of component A, surfactant, iron source, carbon adsorbent, first part water and second part water is 100 parts by weight, wherein the amount of component A is 20-40 parts by weight, the amount of surfactant is 5-10 parts by weight, the amount of iron source is 2-5 parts by weight, the amount of carbon adsorbent is 2-5 parts by weight, and the amount of first part water and second part water is 40-60 parts by weight.

[0016] Preferably, the vegetable oil is soybean oil and / or peanut oil;

[0017] Preferably, the fatty acid is a C16-C20 fatty acid.

[0018] Preferably, the surfactant is selected from at least one of Tween 80, Span 20 and lecithin.

[0019] Preferably, the iron source is a divalent iron salt and / or zero-valent iron;

[0020] Preferably, the D50 particle size of the iron source is ≤100μm, and more preferably ≤10μm;

[0021] Preferably, the divalent ferric salt is selected from ferrous sulfide and / or ferrous sulfate.

[0022] Preferably, the carbon-containing adsorbent is biochar powder and / or activated carbon;

[0023] Preferably, the D50 particle size of the carbon-containing adsorbent is ≤10μm.

[0024] Preferably, in step (1), the first ball milling is carried out in the presence of a protective gas;

[0025] Preferably, the conditions for the first ball milling include: a rotation speed of 1000-3000 rpm and a time of 20-40 min.

[0026] Preferably, in step (2), the second ball milling is carried out in the presence of a protective gas;

[0027] Preferably, the conditions for the second ball milling include: a rotation speed of 1000-2000 rpm and a time of 10-20 min.

[0028] Preferably, in step (3), the third ball milling is carried out in the presence of a protective gas;

[0029] Preferably, the conditions for the third ball milling include: a rotation speed of 2000-3000 rpm and a time of 20-30 min.

[0030] A second aspect of the present invention provides a chlorinated hydrocarbon contaminant remediation agent prepared according to the method described above.

[0031] A third aspect of this invention provides the application of the chlorinated hydrocarbon pollutant remediation agent described above in the remediation of chlorinated hydrocarbon pollutants in groundwater or soil.

[0032] Preferably, the chlorinated hydrocarbon contaminant is selected from at least one of carbon tetrachloride, carbon trichloride, tetrachloroethylene, trichloroethylene, dichloroethylene, trichloroethane, dichloroethane, tetrachloropropane, and trichloropropane.

[0033] The method described in this invention comprises a three-stage ball milling process. The first ball milling pulverizes the iron source, increasing its specific surface area and active sites. Simultaneously, the contact between the iron source and the carbon-containing adsorbent, fatty acid esters, and fatty acids increases the number of carbon-containing groups on its surface, enhancing its stability. A second ball milling process is then performed with the addition of a small amount of water to obtain a water-in-oil emulsion with a viscosity exceeding 3000 cP. Further water is added, and the mixture undergoes deep wet ball milling using the ball milling media to obtain a water-in-oil emulsion remediation agent for chlorinated hydrocarbon pollutants. This emulsion agent has a viscosity below 200 cP and an internal phase particle size of approximately 0.3-4.9 μm, exhibiting the advantage of small particle size. The chlorinated hydrocarbon pollutant remediation agent prepared by the method described in this invention is an agent that combines chemical reduction and biostimulation for microbial degradation of chlorinated hydrocarbons, possessing excellent remediation performance and stability. Even after injection into the ground, it can maintain its emulsified oil-in-oil phase for an extended period. Detailed Implementation

[0034] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0035] 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.

[0036] This invention provides a method for preparing a remediation agent for chlorinated hydrocarbon pollutants, the method comprising the following steps:

[0037] (1) Component A, surfactant, iron source and carbon adsorbent are subjected to a first ball milling;

[0038] (2) The material obtained in step (1) is subjected to a second ball milling with the first part of water;

[0039] (3) The material obtained in step (2) is subjected to a third ball milling with the second part of water;

[0040] Component A is vegetable oil and / or fatty acids;

[0041] The weight ratio of the first portion of water to the second portion of water is 1:(3-5).

[0042] According to some specific embodiments of the present invention, the weight ratio of the first part of water to the second part of water can be 1:3, 1:3.5, 1:4, 1:4.5 or 1:5.

[0043] In this invention, a chlorinated hydrocarbon pollutant remediation agent capable of maintaining long-term stability and high remediation capacity is obtained by using raw materials comprising component A, a surfactant, an iron source, and a carbon-containing adsorbent, combined with three specific ball milling stages. This chlorinated hydrocarbon pollutant remediation agent possesses both chemical reduction and biostimulation of microbial degradation of chlorinated hydrocarbons. The iron salt provides the chemical reduction effect, while agent A provides the biostimulation of microorganisms. This chlorinated hydrocarbon pollutant remediation agent is suitable for the remediation of chlorinated hydrocarbon pollutants in groundwater or soil, and all raw materials are biodegradable, preventing secondary pollution.

[0044] In a preferred embodiment, the total weight of component A, surfactant, iron source, carbon-containing adsorbent, first part water, and second part water is 100 parts by weight. The amount of component A is 20-40 parts by weight, the amount of surfactant is 5-10 parts by weight, the amount of iron source is 2-5 parts by weight, the amount of carbon-containing adsorbent is 2-5 parts by weight, and the amount of first part water and second part water is 40-60 parts by weight. It should be noted that the amounts of first part water and second part water refer to the sum of their amounts. By rationally controlling the amount of each component, the prepared chlorinated hydrocarbon pollutant remediation agent can maintain a stable emulsified oil-in-water phase with a small internal phase particle size. The median D50 internal phase particle size can be effectively controlled within 0.3-4.9 μm, and it exhibits strong stability, remaining stable and not stratified even after 10 days of standing or high-speed centrifugation at 2000 rpm for 20 minutes.

[0045] In this invention, the vegetable oil can be selected from conventionally used vegetable oils in the art, and is a biodegradable agent that will not cause secondary pollution. Preferably, the vegetable oil is soybean oil and / or peanut oil.

[0046] In a preferred embodiment, the fatty acid is a C16-C20 fatty acid, which can be either unsaturated or saturated. Specifically, it can be one or more of palmitic acid, stearic acid, arachidic acid, and oleic acid.

[0047] In this invention, there are no special requirements for the selection of surfactants; any biodegradable surfactant commonly used in the art can be used. In a preferred embodiment, the surfactant is selected from at least one of Tween 80, Span 20, and lecithin.

[0048] In a preferred embodiment, the iron source is a ferrous salt and / or ferrous iron. The ferrous salt may be ferrous sulfide, ferrous sulfate, or other ferrous salts. The ferrous iron may be ferrous iron conventionally used in the art. More preferably, the D50 particle size of the iron source is ≤100 μm, more preferably ≤10 μm.

[0049] In this invention, the carbon-containing adsorbent adsorbs pollutants, slowing their diffusion rate and facilitating their binding with remediation agents. In a preferred embodiment, it is biochar powder and / or activated carbon. The biochar powder and activated carbon can be conventional commercially available products; for example, the biochar powder can be coconut shell activated carbon powder or straw biomass activated carbon. Preferably, the D50 particle size of the carbon-containing adsorbent is ≤10 μm.

[0050] In a preferred embodiment, in step (1), the first ball milling is carried out in the presence of a protective gas to prevent the oxidation of zero-valent iron and divalent iron salts during the ball milling process.

[0051] In this invention, the protective gas used can be nitrogen and / or argon.

[0052] In a preferred embodiment, the conditions for the first ball milling include: a rotation speed of 1000-3000 rpm, more preferably 2000-2500 rpm; and a time of 20-40 min. Performing the first ball milling under high-speed stirring not only further pulverizes substances such as iron sources but also promotes close contact between the components, resulting in a more uniform composition.

[0053] In a preferred embodiment, the grinding balls used in the first ball mill include two different sizes of grinding balls. According to some specific embodiments of the present invention, the grinding balls include grinding ball A and grinding ball B, wherein grinding ball A has a diameter of 6 mm and grinding ball B has a diameter of 2.2-2.4 mm. There are no special requirements for the number of grinding balls; it can be adjusted adaptively according to the amount of material fed.

[0054] In a preferred embodiment, in step (2), the second ball milling is performed in the presence of a protective gas.

[0055] In a preferred embodiment, the conditions for the second ball milling include: a rotation speed of 1000-2000 rpm and a time of 10-20 min.

[0056] In the method described in this invention, in step (2), a small amount of water is added for a second ball milling, which can obtain a high-viscosity material (a water-in-oil emulsion with a viscosity of more than 3000 cP), which is beneficial to obtain an emulsion with smaller internal phase particle size and stronger stability during the conversion from water-in-oil to oil-in-water emulsion.

[0057] In a preferred embodiment, the second ball milling process is performed in the same equipment as the first ball milling process and the same grinding balls are used to complete the ball milling process.

[0058] In a preferred embodiment, in step (3), the third ball milling is performed in the presence of a protective gas.

[0059] In a preferred embodiment, the conditions for the third ball milling include: a rotation speed of 2000-3000 rpm and a time of 20-30 min. In this invention, deep wet ball milling through the third ball milling process is beneficial for obtaining a stable oil-in-water emulsion, with smaller particle size and higher stability of the emulsion phase, and further pulverization of iron salts and carbon-containing adsorbents.

[0060] In a preferred embodiment, the third ball milling process is performed in the same equipment as the first ball milling process and uses the same grinding balls to complete the ball milling process.

[0061] In the method described in this invention, after step (1), the first ball milling pulverizes the iron source, reducing its particle size, increasing its specific surface area, and increasing its active sites. Simultaneously, due to contact with the carbon-containing adsorbent and component A (fatty acid esters and / or fatty acid esters), the iron source's surface gains carbon-containing groups, and an oil film uniformly coats the surface of the iron source particles, increasing its stability and dispersibility, and improving the synergistic removal effect of the components in the agent on chlorinated hydrocarbons. Combined with steps (2) and (3), the mixture obtained in step (1) exists in a uniform and stable form in the aqueous phase. Based on this, the agent prepared by the method described in this invention is an oil-in-water phase, and can maintain this oil-in-water phase for a long time after being injected underground.

[0062] A second aspect of the present invention provides a chlorinated hydrocarbon contaminant remediation agent prepared according to the method described above.

[0063] The preparation method described in this invention has the advantages of simple steps, all reagent components being biodegradable, and no secondary pollution. The chlorinated hydrocarbon remediation agent prepared by the method described in this invention has the advantages of good phase stability, long lifespan, and multiphase coexistence. It can be maintained in groundwater or soil phases for a long time, and its effective slow-release period can be significantly increased. The prepared chlorinated hydrocarbon remediation agent can be stored under sealed conditions at room temperature, maintaining long-term stability and homogeneity without stratification.

[0064] A third aspect of this invention provides the application of the aforementioned chlorinated hydrocarbon remediation agent in the remediation of chlorinated hydrocarbon pollutants in groundwater.

[0065] Preferably, the chlorinated hydrocarbon contaminant includes at least one of carbon tetrachloride, carbon trichloride, tetrachloroethylene, trichloroethylene, dichloroethylene, trichloroethane, dichloroethane, tetrachloropropane, and trichloropropane.

[0066] The chlorinated hydrocarbon pollutant remediation agent described in this invention is convenient for on-site application. It can be applied on-site by direct injection or by using a permeable reactive barrier.

[0067] The present invention will be described in detail below through embodiments, but the scope of protection of the present invention is not limited thereto.

[0068] Example 1

[0069] (1) Place 30g soybean oil, 10g surfactant (composed of 8g Tween 80, 1g Span 20 and 1g lecithin), 2g zero-valent iron (D50 particle size of 1.9μm), and 2g coconut shell activated carbon powder (D50 particle size of 3.5μm) into a ball mill jar, add 20 zirconia grinding balls A (particle size of 6mm) and 20 zirconia grinding balls B (particle size of 2.2-2.4mm), then fill the jar with argon gas as a protective gas, seal it, place it on a planetary ball mill, turn on the ball mill, set the speed to 3000rpm, and the grinding time to 30min;

[0070] (2) Open the ball mill jar in a glove box filled with nitrogen, then add 12.5g of water, seal it, and continue to place it on the planetary ball mill. Turn on the ball mill, set the speed to 1000rpm, and the ball milling time to 20min to obtain a highly viscous mixture with a viscosity of up to 3400cp.

[0071] (3) Open the ball mill jar in a glove box filled with nitrogen, then add 43.5g of water, seal it, place it on a planetary ball mill, turn on the ball mill, set the speed to 3000rpm, and the ball milling time to 30min to obtain chlorinated hydrocarbon pollutant remediation agent S1, at which time the viscosity is about 49cp.

[0072] The chlorinated hydrocarbon pollutant remediation agent S1 prepared in this embodiment has a D50 internal phase particle size of approximately 0.4 micrometers. It remained stable after standing for 10 days without any stratification, and its Zn content was also stable. 2+ Mn 2+ It remains stable in plasma aqueous solution, without any layering or demulsification.

[0073] Example 2

[0074] (1) Place 20g peanut oil, 8.9g surfactant (Tween 80), 3g ferrous sulfide particles (D50 particle size of 5.6μm) and 3g coconut shell activated carbon powder (D50 particle size of 1.6μm) into a ball mill jar, add 20 zirconia grinding balls A (particle size of 6mm) and 20 zirconia grinding balls B (particle size of 2.2-2.4mm), then fill the jar with nitrogen as a protective gas, seal it, place it on a planetary ball mill, turn on the ball mill, set the speed to 2000rpm, and the grinding time to 20min;

[0075] (2) Open the ball mill jar in a glove box filled with nitrogen, then add 10.85g of water, seal it, and continue to place it on the planetary ball mill. Turn on the ball mill, set the speed to 2000rpm, and the ball milling time to 10min to obtain a highly viscous mixture with a viscosity of up to 4200cp.

[0076] (3) Open the ball mill jar in a glove box filled with nitrogen, then add 54.25g of water, seal it, place it on a planetary ball mill, turn on the ball mill, set the speed to 2000rpm, and the ball milling time to 20min to obtain chlorinated hydrocarbon pollutant remediation agent S2, at which time the viscosity is about 39cp.

[0077] The chlorinated hydrocarbon remediation agent S2 prepared in this embodiment has a D50 internal phase particle size of approximately 1.6 micrometers. It remained stable after standing for 10 days without any stratification, and its Zn content was also stable. 2+ Mn 2+ It remains stable in plasma aqueous solution, without any layering or demulsification.

[0078] Example 3

[0079] (1) Place 40g of oleic acid, 8g of surfactant (Tween 80), 5g of ferrous sulfide particles (particle size 0.9μm) and 5g of coconut shell activated carbon powder (particle size 1.8μm) into a ball mill jar, add 20 zirconia grinding balls A (particle size 6mm) and 20 zirconia grinding balls B (particle size 2.2-2.4mm), then fill the jar with nitrogen as a protective gas, seal it, place it on a planetary ball mill, turn on the ball mill, set the speed to 2500rpm, and the ball milling time to 25min;

[0080] (2) Open the ball mill jar in a glove box filled with nitrogen, then add 10.5g of water, seal it, and continue to place it on the planetary ball mill. Turn on the ball mill, set the speed to 1000rpm, and the ball milling time to 15min to obtain a highly viscous mixture with a viscosity of up to 4300cp.

[0081] (3) Open the ball mill jar in a glove box filled with nitrogen, then add 31.5g of water, seal it, place it on a planetary ball mill, turn on the ball mill, set the speed to 2500rpm, and the ball milling time to 25min to obtain chlorinated hydrocarbon pollutant remediation agent S3, at which time the viscosity is about 51cp.

[0082] The chlorinated hydrocarbon pollutant remediation agent S3 prepared in this embodiment has a D50 internal phase particle size of approximately 1.4 micrometers. It remained stable after standing for 10 days without any stratification, and its Zn content was also stable. 2+ Mn 2+ It remains stable in plasma aqueous solution, without any layering or demulsification.

[0083] Example 4

[0084] (1) Place 30g palmitoleic acid, 8g surfactant (lecithin), 3g ferrous sulfide particles (particle size 0.9μm) and 3g coconut shell activated carbon powder (particle size 3.μm) into a ball mill jar, add 20 zirconia grinding balls A (particle size 6mm) and 20 zirconia grinding balls B (particle size 2.2-2.4mm), then fill the jar with nitrogen as a protective gas, seal it, place it on a planetary ball mill, turn on the ball mill, set the speed to 2500rpm, and the ball milling time to 25min;

[0085] (2) Open the ball mill jar in a glove box filled with nitrogen, then add 14g of water, seal it, and continue to place it on the planetary ball mill. Turn on the ball mill, set the speed to 1000rpm, and the ball milling time to 15min to obtain a highly viscous mixture with a viscosity of up to 4600cp.

[0086] (3) Open the ball mill jar in a glove box filled with nitrogen, then add 42g of water, seal it, place it on a planetary ball mill, turn on the ball mill, set the speed to 2500rpm, and the ball milling time to 25min to obtain chlorinated hydrocarbon pollutant remediation agent S4, at which time the viscosity is about 28cp.

[0087] The chlorinated hydrocarbon pollutant remediation agent S4 prepared in this embodiment has a D50 internal phase particle size of 2.3 micrometers. It remained stable after standing for 10 days without any stratification, and its Zn content was also stable. 2+ Mn 2+ It remains stable in plasma aqueous solution, without any layering or demulsification.

[0088] Example 5

[0089] (1) Place 35g soybean oil, 8g surfactant (composed of 6g Tween 80, 1g Span 20 and 1g lecithin), 3g zero-valent iron (particle size of 5.6μm), and 3g coconut shell activated carbon powder (particle size of 5.4μm) into a ball mill jar, add 20 zirconia grinding balls A (particle size of 6mm) and 20 zirconia grinding balls B (particle size of 2.2-2.4mm), then fill the jar with argon gas as a protective gas, seal it, place it on a planetary ball mill, turn on the ball mill, set the speed to 3000rpm, and the grinding time to 30min;

[0090] (2) Open the ball mill jar in a glove box filled with nitrogen, then add 10.2g of water, seal it, and continue to place it on the planetary ball mill. Turn on the ball mill, set the speed to 1000rpm, and the ball milling time to 20min to obtain a highly viscous mixture with a viscosity of up to 3900cp.

[0091] (3) Open the ball mill jar in a glove box filled with nitrogen, then add 40.8g of water, seal it, place it on a planetary ball mill, turn on the ball mill, set the speed to 3000rpm, and the ball milling time to 30min to obtain chlorinated hydrocarbon pollutant remediation agent S5, at which time the viscosity is about 25cp.

[0092] The chlorinated hydrocarbon pollutant remediation agent S5 prepared in this embodiment has a D50 internal phase particle size of approximately 2.4 micrometers. It remained stable after standing for 10 days without any stratification, and its Zn content was also stable. 2+ Mn 2+ It remains stable in plasma aqueous solution, without any layering or demulsification.

[0093] Example 6

[0094] (1) Place 25g peanut oil, 10g surfactant (Tween 80), 4g ferrous sulfide particles (particle size 2.8μm) and 4g coconut shell activated carbon powder (particle size 2.5μm) into a ball mill jar, add 20 zirconia grinding balls A (particle size 6mm) and 20 zirconia grinding balls B (particle size 2.2-2.4mm), then fill the jar with nitrogen as a protective gas, seal it, place it on a planetary ball mill, turn on the ball mill, set the speed to 2000rpm, and the grinding time to 20min;

[0095] (2) Open the ball mill jar in a glove box filled with nitrogen, then add 11.4g of water, seal it, and continue to place it on the planetary ball mill. Turn on the ball mill, set the speed to 2000rpm, and the ball milling time to 10min to obtain a highly viscous mixture with a viscosity of up to 3600cp.

[0096] (3) Open the ball mill jar in a glove box filled with nitrogen, then add 45.6g of water, seal it, place it on a planetary ball mill, turn on the ball mill, set the speed to 2000rpm, and the ball milling time to 20min to obtain chlorinated hydrocarbon pollutant remediation agent S6, at which time the viscosity is about 31cp.

[0097] The chlorinated hydrocarbon pollutant remediation agent S6 prepared in this embodiment has a D50 internal phase particle size of approximately 1.8 micrometers. It remained stable after standing for 10 days without any stratification, and its Zn content was also stable. 2+ Mn 2+ It remains stable in plasma aqueous solution, without any layering or demulsification.

[0098] Example 7

[0099] (1) Accurately weigh 30g soybean oil, 10g surfactant, 2g micron-sized zero-valent iron, and 2g micron-sized coconut shell activated carbon powder, including 8g Tween 80, 1g Span 20, and 1g lecithin in the surfactant. Place it in a ball mill jar, add 20 zirconia grinding balls (6mm in diameter) and 20 zirconia grinding balls (2.2-2.4mm in diameter), then fill the jar with argon gas as a protective gas, seal it, place it on a planetary ball mill, turn on the ball mill, set the speed to 800rpm, and the grinding time to 15min;

[0100] (2) After stopping, open the ball mill jar in a glove box filled with nitrogen, then add 12.5g of water, seal it, and continue to place it on the planetary ball mill. Turn on the ball mill, set the speed to 800rpm, and the ball milling time to 20min to obtain a highly viscous mixed substance with a viscosity of up to 2700cp.

[0101] (3) Then open the ball mill jar in a glove box filled with nitrogen, and add 43.5g of water. After sealing, place it on a planetary ball mill, turn on the ball mill, set the speed to 1500rpm, and after 30min of ball milling, obtain chlorinated hydrocarbon pollutant remediation agent S7, at which time the viscosity is about 14cp.

[0102] The chlorinated hydrocarbon pollutant remediation agent S7 prepared in this embodiment has a D50 internal phase particle size of 6.8 micrometers. After standing for 10 days, it exhibits stratification. 2+ Mn 2+ Demulsification occurred when the plasma aqueous solution was left to stand for 4 days.

[0103] Comparative Example 1

[0104] 30g soybean oil, 10g surfactant (composed of 8g Tween 80, 1g Span 20 and 1g lecithin), 2g zero-valent iron (D50 particle size of 1.9μm), 2g coconut shell activated carbon powder (D50 particle size of 3.5μm) and 56g water were placed in a ball mill jar. 20 zirconia grinding beads A (particle size of 6mm) and 20 zirconia grinding beads B (particle size of 2.2-2.4mm) were added. Argon gas was then introduced into the jar as a protective gas, and after sealing, it was placed on a planetary ball mill. The ball mill was turned on, the speed was set to 3000rpm, and the milling time was 80min to obtain repair agent D1, at which point the viscosity was approximately 39cp.

[0105] The repair agent D1 prepared in this comparative example had an internal phase particle size of 11.5 micrometers at D50. After standing for 3 days, it exhibited stratification, and in Zn... 2+ Mn 2+ Demulsification occurs when the solution is left to stand for 7 hours in an ionic aqueous solution.

[0106] Comparative Example 2

[0107] (1) Place 40g of oleic acid, 8g of surfactant (Tween 80), 5g of ferrous sulfide particles (D50 particle size of 0.9μm), 5g of coconut shell activated carbon powder (D50 particle size of 1.8μm) and 42g of water into a ball mill jar, add 20 zirconia grinding balls A (particle size of 6mm) and 20 zirconia grinding balls B (particle size of 2.2-2.4mm), then fill the jar with nitrogen as a protective gas, seal it, place it on a planetary ball mill, turn on the ball mill, set the speed to 2500rpm, and the ball milling time to 65min to obtain repair agent D2, at which time the viscosity is 36cp.

[0108] The repair agent D2 prepared in this comparative example had an internal phase particle size of 15.4 micrometers at D50. After standing for 2 days, it exhibited stratification, and in Zn... 2+ Mn 2+ Demulsification occurred when the plasma aqueous solution was left to stand for 4 hours.

[0109] Comparative Example 3

[0110] The method described in Example 1 was implemented, except that the amount of water added in steps (2) and (3) was 28g.

[0111] Specifically:

[0112] (1) Place 30g soybean oil, 10g surfactant (composed of 8g Tween 80, 1g Span 20 and 1g lecithin), 2g zero-valent iron (D50 particle size of 1.9μm), and 2g coconut shell activated carbon powder (D50 particle size of 3.5μm) into a ball mill jar, add 20 zirconia grinding balls A (particle size of 6mm) and 20 zirconia grinding balls B (particle size of 2.2-2.4mm), then fill the jar with argon gas as a protective gas, seal it, place it on a planetary ball mill, turn on the ball mill, set the speed to 3000rpm, and the grinding time to 30min;

[0113] (2) Open the ball mill jar in a glove box filled with nitrogen, then add 28g of water, seal it, and continue to place it on the planetary ball mill. Turn on the ball mill, set the speed to 1000rpm, and the ball milling time to 20min to obtain a highly viscous mixture with a viscosity of about 1800cp.

[0114] (3) Open the ball mill jar in a glove box filled with nitrogen, then add 28g of water, seal it, place it on a planetary ball mill, turn on the ball mill, set the speed to 3000rpm, and the ball milling time to 30min to obtain repair agent D3, at which time the viscosity is about 52cp.

[0115] The repair agent D3 prepared in this comparative example had an internal phase particle size of 9.6 micrometers at D50. After standing for 2 days, it exhibited stratification, and in Zn... 2+ Mn 2+ Demulsification occurred when the plasma aqueous solution was left to stand for 10 hours.

[0116] Comparative Example 4

[0117] The method described in Example 1 was implemented, except that the amount of water added in step (2) was 18.7g and the amount of water added in step (3) was 37.3g.

[0118] Specifically:

[0119] (1) Place 30g soybean oil, 10g surfactant (composed of 8g Tween 80, 1g Span 20 and 1g lecithin), 2g zero-valent iron (D50 particle size of 1.9μm), and 2g coconut shell activated carbon powder (D50 particle size of 3.5μm) into a ball mill jar, add 20 zirconia grinding balls A (particle size of 6mm) and 20 zirconia grinding balls B (particle size of 2.2-2.4mm), then fill the jar with argon gas as a protective gas, seal it, place it on a planetary ball mill, turn on the ball mill, set the speed to 3000rpm, and the grinding time to 30min;

[0120] (2) Open the ball mill jar in a glove box filled with nitrogen, then add 18.7g of water, seal it, and continue to place it on the planetary ball mill. Turn on the ball mill, set the speed to 1000rpm, and the ball milling time to 20min to obtain a highly viscous material with a viscosity of up to 3800cp.

[0121] (3) Open the ball mill jar in a glove box filled with nitrogen, then add 37.3g of water, seal it, place it on a planetary ball mill, turn on the ball mill, set the speed to 3000rpm, and the ball milling time to 30min to obtain repair drug D4, at which time the viscosity is about 39cp.

[0122] The repair agent D4 prepared in this comparative example had an internal phase particle size of 7.9 micrometers at D50. After standing for 6 days, it exhibited stratification, and in Zn... 2+ Mn 2+ When the plasma aqueous solution was left to stand for 13 hours, stratification and demulsification occurred.

[0123] Test case

[0124] A 25 mg / kg tetrachloroethylene-contaminated aquifer sediment was obtained from contaminated soil at a company site. The sediment had a water content of 35%. The aquifer sediment was placed in a tube and sent to the laboratory, where it was placed directly in a glove box. Air contact was avoided throughout the entire process.

[0125] Accurately weigh 500 mg each of the products prepared in Examples 1-4, Example 7, and Comparative Example 3, and add them to 50 g of the above-mentioned contaminated aquifer sediment. This operation was performed in a glove box. Then, the mixture was placed in a constant temperature incubator for incubation, and the dissolved oxygen (unit: ppm), redox potential (unit: mV), and tetrachloroethylene contaminant concentration (unit: ppm) were measured periodically. The results are shown in Tables 1-3.

[0126] After a 270-day experiment, it was found that throughout the process, the dissolved oxygen content in S1, S2, S3, S4, and S7 rapidly decreased from an initial 2.4 ppm to below 0.3 ppm within 10 days, and remained at a very low level for the subsequent 270 days. Meanwhile, the dissolved oxygen content in D3 slowly decreased from an initial 2.6 ppm to below 0.4 ppm within 30 days.

[0127] The redox potentials (ORPs) of S1, S2, S3, S4, and S7 decreased rapidly from an initial 103 mV to -76 mV within 10 days, and then slowly decreased to -110 mV. This indicates that due to the introduction of an electron donor, the entire environment transformed from an oxidizing environment to a reducing environment, providing favorable reduction conditions for the reductive dechlorination of chlorinated hydrocarbons. Meanwhile, the redox potential of D3 slowly decreased from an initial 113 mV to below -59 mV within 30 days.

[0128] The pollutant concentrations started at 25 ppm. For samples S1, S2, S3, and S4, the concentrations decreased significantly in the first 10 days, reaching a minimum of 14 ppm, and then decreased to undetectable levels within 90 days. For S7, the concentration remained relatively stable in the first 10 days, but decreased to a low level within 270 days. For sample D3, the pollutant concentration decreased to 18 ppm in the first 10 days and then to undetectable levels within 210 days.

[0129] For the first 10 days, the concentration remained relatively stable at around 25 ppm. This was likely due to heterogeneity in the initial mixing of sediment and reagent, as well as systematic errors in the testing process. However, it indicates that the pollutant concentration did not change significantly during this short period. Later, however, the pollutant concentration changed dramatically. Since this occurred after 40 days, the rapid decrease in concentration suggests that after several dozen days of microbial growth, dechlorinating bacteria had become the dominant bacterial community, rapidly degrading chlorinated hydrocarbons and causing a rapid reduction in their concentration.

[0130] Table 1 Changes in dissolved oxygen content

[0131] time S1 S2 S3 S4 S7 D3 initial 2.4 2.4 2.5 2.3 2.4 2.6 3d 1.6 1.8 1.4 1.6 1.5 2.0 10d 0.2 0.2 0.3 0.2 0.5 0.9 30d 0.3 0.3 0.1 0.2 0.2 0.4 60d 0.2 0.3 0.2 0.2 0.2 0.3 90d 0.1 0.2 0.3 0.3 0.2 0.3 150d 0.3 0.2 0.1 0.1 0.2 0.2 210d 0.4 0.1 0.2 0.2 0.2 0.4 270d 0.3 0.2 0.2 0.3 0.2 0.3

[0132] Table 2 ORP Changes

[0133]

[0134]

[0135] Table 3. Changes in tetrachloroethylene pollutant concentrations

[0136] time S1 S2 S3 S4 S7 D3 initial 25 25 25 25 25 25 3d 20 21 20 20 24.6 23 10d 14.1 13.8 14.3 14.1 24.8 18 30d 6.3 6.8 5.9 6.1 22.5 13.2 60d 1.6 2.1 1.7 1.4 14.3 7.9 90d 0 0 0 0 6.8 5.4 150d 0 0 0 0 1.2 2.3 210d 0 0 0 0 0 0 270d 0 0 0 0 0 0

[0137] 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 method for preparing a remediation agent for chlorinated hydrocarbon pollutants, characterized in that, The method includes the following steps: (1) Component A, surfactant, iron source and carbon adsorbent are subjected to a first ball milling; (2) The material obtained in step (1) is subjected to a second ball milling with the first part of water; (3) The material obtained in step (2) is subjected to a third ball milling with the second part of water; Component A is vegetable oil and / or fatty acids; The weight ratio of the first portion of water to the second portion of water is 1:(3-5).

2. The method according to claim 1, characterized in that, The total weight of component A, surfactant, iron source, carbon adsorbent, first part water, and second part water is 100 parts by weight. The amount of component A is 20-40 parts by weight, the amount of surfactant is 5-10 parts by weight, the amount of iron source is 2-5 parts by weight, the amount of carbon adsorbent is 2-5 parts by weight, and the amount of first part water and second part water is 40-60 parts by weight.

3. The method according to claim 1 or 2, characterized in that, The vegetable oil is soybean oil and / or peanut oil; Preferably, the fatty acid is a C16-C20 fatty acid.

4. The method according to any one of claims 1-3, characterized in that, The surfactant is selected from at least one of Tween 80, Span 20 and lecithin.

5. The method according to any one of claims 1-4, characterized in that, The iron source is a divalent iron salt and / or zero-valent iron; Preferably, the D50 particle size of the iron source is ≤100μm, and more preferably ≤10μm; Preferably, the divalent ferric salt is selected from ferrous sulfide and / or ferrous sulfate.

6. The method according to any one of claims 1-5, characterized in that, The carbon-containing adsorbent is biochar powder and / or activated carbon; Preferably, the D50 particle size of the carbon-containing adsorbent is ≤10μm.

7. The method according to claim 1, characterized in that, In step (1), the first ball milling is carried out in the presence of a protective gas; Preferably, the conditions for the first ball milling include: a rotation speed of 1000-3000 rpm and a time of 20-40 min.

8. The method according to claim 1 or 7, characterized in that, In step (2), the second ball milling is carried out in the presence of a protective gas; Preferably, the conditions for the second ball milling include: a rotation speed of 1000-2000 rpm and a time of 10-20 min.

9. The method according to claim 1 or 6, characterized in that, In step (3), the third ball milling is carried out in the presence of a protective gas; Preferably, the conditions for the third ball milling include: a rotation speed of 2000-3000 rpm and a time of 20-30 min.

10. A chlorinated hydrocarbon pollutant remediation agent prepared by the method according to any one of claims 1-9.

11. The application of the chlorinated hydrocarbon pollutant remediation agent according to claim 9 in the remediation of chlorinated hydrocarbon pollutants in groundwater or soil.

12. The application according to claim 11, characterized in that, The chlorinated hydrocarbon contaminant is selected from at least one of carbon tetrachloride, carbon trichloride, tetrachloroethylene, trichloroethylene, dichloroethylene, trichloroethane, dichloroethane, tetrachloropropane, and trichloropropane.

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