A heavy non-aqueous phase contaminant self-identifying remediation material, and a preparation method and application thereof

Abstract

The present application relates to the field of site organic pollutant remediation technology field, and discloses a kind of site heavy non-aqueous phase pollutant self-identification repair material and its preparation method and application.The heavy non-aqueous phase pollutant self-identification repair material has multiple core-shell structure, and the multiple core-shell structure has inner core, intermediate layer and coating layer sequentially distributed from inside to outside;Wherein, the inner core contains modified zero-valent iron, electron shuttle and biological stimulant material;The intermediate layer contains deoxidizing agent;The coating layer contains fat-soluble material.The heavy non-aqueous phase pollutant self-identification repair material has the selective identification function of DNAPL phase pollutant, and the coating layer can self-dissolve when encountering DNAPL phase pollutant or high concentration water in oil, so as to start DNAPL phase pollutant remediation agent release, realize DNAPL phase timely and efficient purification removal.

Description

Technical Field

[0001] This invention relates to the field of site organic pollutant remediation technology, specifically to a self-identifying remediation material for heavy non-aqueous phase pollutants in a site, its preparation method, and its application. Background Technology

[0002] In industries such as petrochemicals, fine chemicals, printing and dyeing, and pharmaceuticals, large quantities of raw materials and products enter the natural environment during production, storage, and transportation, causing varying degrees of pollution to soil and groundwater. Organic solvents, represented by chlorinated hydrocarbons (CHPs) and polychlorinated biphenyls (PCBs), are persistent pollutants. These organic compounds, containing one or more chlorine atoms, have a higher density than groundwater, lower solubility, and are characterized by low viscosity and toxicity ("three-fold toxicity"). They are called heavy non-aqueous phase pollutants (DNAPLs) and can penetrate both unsaturated and saturated zones, remaining at the bottom of aquifers. Influenced by groundwater flow velocity and the heterogeneity of the medium, DNAPL pollutants from chlorinated hydrocarbons migrate and diffuse, forming pollution plumes that pose a significant risk to the health and lives of people in and around the plant area. Therefore, developing a highly efficient and precise targeted material is of great significance, addressing the challenges of low utilization rates and poor precision in DNAPL pollution remediation agents at petrochemical sites.

[0003] Remediation of DNAPL pollution, primarily composed of chlorine-containing pollutants, mainly employs technologies such as in-situ chemical oxidation-reduction, permeable reactive barriers, in-situ extraction, and microbial degradation. These technologies have been applied in engineering projects both domestically and internationally. In-situ chemical oxidation-reduction technology involves injecting remediation agents under pressure into the DNAPL-contaminated strata. Through the oxidation-reduction reaction between the agent and the pollutants, the DNAPL and oil pollutants in the water are purified and removed. For example, patent application CN106269823A discloses a method for remediating soil contaminated with high concentrations of organic matter. The core of this technology is the injected oxidant or reducing agent. DNAPL pollution in soil and groundwater accumulates at the bottom of the aquifer, and its migration path is unclear due to groundwater flow velocity and soil heterogeneity. The agent is consumed by organic matter in the soil before acting on the DNAPL pollution, significantly reducing its utilization rate. In-situ extraction treatment technology typically uses power pumps to generate negative pressure, extracting DNAPL and contaminated groundwater to the surface for purification. For example, patent application CN212954525U discloses a system for extracting and treating heavy non-aqueous phase liquid pollutants in groundwater, and patent application CN111137941A discloses a technology for remediating non-aqueous phase pollution in groundwater. However, this type of extraction treatment technology lacks specificity for remediation, is prone to DNAPL contamination recurrence after remediation, and still requires purification after extraction, resulting in high overall operating costs. Microbial degradation technology mainly utilizes the metabolic activities of indigenous or exogenous microorganisms to transform or degrade DNAPL pollutants into non-polluting substances. Exogenous microorganisms, such as the composite biological agent for remediating PCB-contaminated soil disclosed in patent application CN111235077B, and the composite biological agent and its application in remediating PCB-contaminated soil disclosed in patent application CN107586747B, face significant challenges in maintaining the activity of injected bacteria in complex geological environments.

[0004] Among the aforementioned technologies, in-situ reductive dechlorination is a highly efficient DNAPL repair technique. The main agent is zero-valent iron, combined with anaerobic microbial degradation to remove chlorine-containing pollutants. It has received considerable research attention in recent years. The reactions occurring during the reductive dechlorination process are as follows:

[0005] 2Fe 0 +4H + +O2→2Fe 2+ +2H2O

[0006] Fe 0 +2H₂O→Fe 2+ +H2↑+2OH -

[0007] R-Cl+Fe 0 +H+ →R-H+Fe 2+ +Cl -

[0008] 2Fe 2+ +R-Cl+H + →2Fe 3+ +R-H+Cl - .

[0009] During the dechlorination process of zero-valent iron, microbial degradation also occurs, Fe 0 The H2 produced by its reaction with water can serve as an electron donor for microbial metabolism to achieve biological dechlorination, and zero-valent iron can also stimulate microorganisms to secrete extracellular substances with the ability to degrade pollutants. For example, patent application CN109019819A discloses a reducing agent for in-situ remediation of groundwater contaminated with chlorinated hydrocarbons and its preparation and application methods; patent application CN114479872A discloses a formable in-situ remediation slow-release agent for chlorinated hydrocarbon pollutants and its preparation method; and patent application CN114477474A discloses an in-situ remediation agent for groundwater contaminated with chlorinated hydrocarbons, its manufacturing method, and its application. These patents are all based on the above principles. Although the materials involved can achieve zero-valent iron-microbial synergistic remediation of chlorinated pollutants, there are still many problems. For example, the specificity and selectivity of the agent materials are poor, and they will be consumed by groundwater and geochemical components after being injected underground, resulting in low utilization rate; during production, storage, transportation, and use, the zero-valent iron component is easily oxidized; in complex systems, zero-valent iron will undergo various reactions with groundwater and geochemical components, and the bio-carbon source co-metabolism matrix incorporated in the above materials is prone to acid production, causing passivation, flocculation, and adhesion of zero-valent iron surface, resulting in reduced electron transfer efficiency, etc.

[0010] Given a clear understanding of the concentration and distribution of low-concentration chlorinated hydrocarbon pollutants in soil and groundwater, existing in-situ chemical oxidation-reduction, in-situ extraction, and microbial degradation remediation technologies and materials can basically meet the remediation and treatment needs. However, for chlorinated hydrocarbon pollutants existing in the DNAPL phase, there are still many problems in terms of the accuracy of remediation and treatment and the removal capacity. Furthermore, there is a lack of key materials with specific selection to address the concealment and easy migration of chlorinated hydrocarbon DNAPL phase pollutants. Summary of the Invention

[0011] The purpose of this invention is to overcome the problems of tailing and rebound in the remediation of DNAPL pollutants by existing technologies and agents, low effective utilization rate of agents, multiple migration modes of DNAPL in complex strata, irregular pollution contours that make tailing and rebound phenomena difficult to detect and treat in the first time, and lack of efficient identification selectivity. The invention provides a self-identifying remediation material for heavy non-aqueous phase pollutants, its preparation method and application.

[0012] To achieve the above objectives, the present invention provides a self-identifying and remediating material for heavy non-aqueous pollutants, wherein the heavy non-aqueous pollutant self-identifying and remediating material has a multi-core-shell structure, wherein the multi-core-shell structure has a core, an intermediate layer and a coating layer distributed sequentially from the inside to the outside.

[0013] The core contains modified zero-valent iron, an electron shuttle, and biostimulatory materials.

[0014] The intermediate layer contains a deoxidizer;

[0015] The coating layer contains a fat-soluble material.

[0016] Preferably, the kernel has a particle size of 20-35 μm.

[0017] Preferably, the core further comprises a first adhesive;

[0018] Preferably, the total weight of modified zero-valent iron, electron shuttle, biostimulant material and first adhesive is 100% by weight, the content of modified zero-valent iron is 40-60% by weight, the content of electron shuttle is 10-20% by weight, the content of biostimulant material is 10-40% by weight, and the content of first adhesive is 5-15% by weight.

[0019] Preferably, the modified zero-valent iron is selected from one or more of polyethylene glycol modified zero-valent iron, carboxymethyl cellulose modified zero-valent iron, and sodium oleate modified zero-valent iron;

[0020] Preferably, the electron shuttle is selected from sodium anthraquinone-2,6-disulfonate and / or riboflavin;

[0021] Preferably, the biostimulant material is selected from one or more of yeast extract, nitrogen source, and phosphorus source.

[0022] Preferably, the thickness of the intermediate layer is 5-10 μm.

[0023] Preferably, the intermediate layer further comprises a second adhesive;

[0024] Preferably, the deoxidizing agent is selected from sodium sulfite, ascorbic acid, glucose oxidase, etc.

[0025] Preferably, the thickness of the coating layer is 10-20 μm.

[0026] Preferably, the fat-soluble material is selected from fatty acids and / or paraffin;

[0027] Preferably, the fatty acid is selected from C16-C20 fatty acids.

[0028] A second aspect of the present invention provides a method for preparing a self-identifying repair material, the method comprising the following steps:

[0029] S1: Modified zero-valent iron, electron shuttle, biostimulant material and first binder are mixed and then granulated to obtain the core;

[0030] S2; The deoxidizer, the second binder and the core are mixed and then granulated to form an intermediate layer on the surface of the core;

[0031] S3: Heat the fat-soluble material to obtain a coating solution, and use the coating solution to coat the material obtained in step S2 to form a coating layer on the surface of the intermediate layer.

[0032] Preferably, in step S1, the total weight of modified zero-valent iron, electron shuttle, biostimulant material and first adhesive is 100% by weight, the content of modified zero-valent iron is 40-60% by weight, the content of electron shuttle is 10-20% by weight, the content of biostimulant material is 10-40% by weight, and the content of adhesive is 5-15% by weight.

[0033] Preferably, the modified zero-valent iron is selected from one or more of polyethylene glycol modified zero-valent iron, carboxymethyl cellulose modified zero-valent iron, and sodium oleate modified zero-valent iron;

[0034] Preferably, the electron shuttle is selected from sodium anthraquinone-2,6-disulfonate and / or riboflavin;

[0035] Preferably, the biostimulant material is selected from one or more of yeast extract, nitrogen source, and phosphorus source.

[0036] Preferably, the kernel has a particle size of 20-35 μm.

[0037] Preferably, in step S2, the deoxidizing agent is selected from one or more of sodium sulfite, ascorbic acid, and glucose oxidase.

[0038] Preferably, the ratio of the deoxidizer to the second adhesive is 5-8:1.

[0039] Preferably, in step S2, the ratio of the total weight of the deoxidizer and the second adhesive to the weight of the core is 1:2-3.

[0040] Preferably, in step S2, the thickness of the intermediate layer is 5-10 μm.

[0041] Preferably, the specific process of step S3 includes:

[0042] The fat-soluble material is heated to obtain a coating solution. The material obtained in step S2 is placed in a preheated fluidized bed coating machine, and then the coating solution is sprayed in for coating. Then, it is dried.

[0043] Preferably, in step S3, the volume ratio of the coating solution to the material obtained in step S2 is 1:2-5.

[0044] Preferably, in step S3, the thickness of the coating layer is 10-20 μm.

[0045] Preferably, in step S3, the fat-soluble material is selected from fatty acids and / or paraffin;

[0046] Preferably, the fatty acid is selected from C16-C20 fatty acids.

[0047] The third aspect of the present invention provides a self-identifying and remediating material for heavy non-aqueous phase pollutants prepared by the method described above.

[0048] The fourth aspect of this invention provides the application of the self-identifying remediation material for heavy non-aqueous pollutants described above in the remediation of heavy non-aqueous pollutants.

[0049] Compared with the prior art, the present invention has the following advantages:

[0050] 1. The heavy non-aqueous phase pollutant self-identification remediation material of the present invention has the selective recognition function of DNAPL phase pollutants. When the coating layer encounters DNAPL phase pollutants or high concentrations of oil in water, it can undergo self-dissolution, thereby initiating the release of DNAPL phase pollutant remediation agents and achieving timely and efficient purification and removal of DNAPL phase. It can also avoid the consumption of remediation agents by geochemical and organic matter in soil and groundwater environments, improve the effective utilization rate of remediation agents, and achieve timely removal when DNAPL diffuses or rebounds. Furthermore, the coating layer can also protect the internal agent material from oxidation.

[0051] 2. The intermediate layer of the heavy non-aqueous pollutant self-identification and remediation material of the present invention contains sulfites, which can produce a deoxygenation reaction on dissolved oxygen in groundwater, forming an anaerobic environment that is conducive to the reduction, dechlorination and biodegradation of chlorinated hydrocarbons; it can also protect zero-valent iron and prevent zero-valent iron from being oxidized by water and air during storage, transportation and injection.

[0052] 3. The self-identification and remediation material for heavy non-aqueous pollutants described in this invention uses modified nano-zero-valent iron as the final electron donor for reductive dechlorination and anaerobic microbial degradation, eliminating the need for added organic carbon sources. This avoids the loss of zero-valent iron due to degradation and acidification of organic carbon sources. Furthermore, the modified nano-zero-valent iron used is lipophilic, enhancing the targeted removal capacity of DNAPL phase and oil pollutants in water.

[0053] 4. The heavy non-aqueous phase pollutant self-identification and remediation material of the present invention uses an electron shuttle in combination with modified zero-valent iron, which can enhance electron transfer efficiency, effectively promote the reducing dechlorination ability of modified zero-valent iron, improve the microbial degradation of chlorine-containing pollutants and secondary organic pollutants under anaerobic conditions, and reduce the barrier effects of iron surface passivation and attachments. Attached Figure Description

[0054] Figure 1 This is a schematic diagram of the structure of the self-identification and repair material for heavy non-aqueous pollutants described in this invention.

[0055] Explanation of reference numerals in the attached figures

[0056] 1. Coating layer 2. Intermediate layer

[0057] 3 kernels Detailed Implementation

[0058] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0059] 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.

[0060] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating relative importance or implying the number of technical features indicated. Therefore, unless otherwise stated, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature; "multiple" means two or more. The term "comprising" and any variations thereof mean non-exclusive inclusion, where one or more other features, integers, steps, operations, units, components, and / or combinations thereof may be present or added.

[0061] The first aspect of this invention provides a self-identifying and remediating material for heavy non-aqueous pollutants, in conjunction with reference to [reference needed]. Figure 1 The heavy non-aqueous pollutant self-identification and remediation material has a multi-core-shell structure, which has a core 3, an intermediate layer 2 and a coating layer 1 distributed from the inside to the outside.

[0062] The core 3 contains modified zero-valent iron, an electron shuttle, and biostimulatory materials.

[0063] The intermediate layer 2 contains a deoxidizer;

[0064] The coating layer 1 contains a fat-soluble material.

[0065] In a preferred embodiment, the kernel 3 is spherical in shape.

[0066] More preferably, the particle size of the kernel 3 is 20-35 μm.

[0067] In a preferred embodiment, the core 3 further comprises a first adhesive. Using the first adhesive helps maintain the stability of the shape and structure of the core 3.

[0068] In a preferred embodiment, the total weight of modified zero-valent iron, electron shuttle, biostimulant material and first adhesive is 100% by weight, the content of modified zero-valent iron is 40-60% by weight, the content of electron shuttle is 10-20% by weight, the content of biostimulant material is 10-40% by weight, and the content of first adhesive is 5-15% by weight.

[0069] Preferably, the modified zero-valent iron is selected from one or more of polyethylene glycol modified zero-valent iron, carboxymethyl cellulose modified zero-valent iron, and sodium oleate modified zero-valent iron.

[0070] Preferably, the electron shuttle is selected from sodium anthraquinone-2,6-disulfonate and / or riboflavin;

[0071] Preferably, the biostimulant material is selected from one or more of yeast extract, nitrogen source, and phosphorus source.

[0072] More preferably, the nitrogen source is selected from ammonium chloride and / or potassium nitrate; the phosphorus source is selected from disodium hydrogen phosphate and / or potassium dihydrogen phosphate.

[0073] In a preferred embodiment, when the biostimulant is yeast extract, nitrogen source and phosphorus source, the weight ratio of the three is 10-16:8-13:1-3.

[0074] In this invention, modified zero-valent iron is used to reduce the aggregation caused by magnetic attraction and electrostatic attraction, resulting in better suspension fluidity and affinity for DNAPL. The use of an electron shuttle in conjunction with modified zero-valent iron promotes electron transfer efficiency in reductive dechlorination and anaerobic microbial degradation. Biostimulants are used as inorganic nutrients to stimulate the growth of indigenous microorganisms in conjunction with zero-valent iron. Based on this, this invention uses a combination of modified zero-valent iron, electron shuttle, and biostimulants as the main remediation agent, achieving highly efficient removal of DNAPL phase pollutants through a reductive dechlorination-anaerobic microbial degradation process.

[0075] In a preferred embodiment, the thickness of the intermediate layer 2 is 5-10 μm.

[0076] In a preferred embodiment, the intermediate layer 2 further comprises a second adhesive. Using the second adhesive facilitates the formation of a structurally stable intermediate layer.

[0077] In a preferred embodiment, the deoxidizing agent is selected from one or more of sodium sulfite, ascorbic acid, and glucose oxidase.

[0078] In a preferred embodiment, the thickness of the coating layer 1 is 10-20 μm, and more preferably...

[0079] In a preferred embodiment, the fat-soluble material is selected from fatty acids and / or paraffin.

[0080] More preferably, the fatty acid is selected from C16-C20 fatty acids. For example, it can be stearic acid, etc.

[0081] In this invention, the main component of the coating layer is a lipid-soluble material, which allows the self-recognition repair material to dissolve upon contact with the DNAPL phase or high-concentration oil pollutants in water. This triggers the self-recognition process, releasing the DNAPL phase pollutant repair agent from the shell within approximately 2-5 minutes. The intermediate layer contains a deoxygenating agent. When the coating layer recognizes the dissolution of the DNAPL phase, it releases the deoxygenating agent, which reacts with dissolved oxygen in the groundwater to create an anaerobic environment. The dissolved oxygen in the groundwater is below 0.1 mg / L, and this anaerobic environment can last for 50-70 days. After the intermediate layer releases the deoxygenating agent, the modified zero-valent iron, electron shuttle, and biostimulant contained in the core are released into the anaerobic environment created by the deoxygenating agent. Through the synergistic effect of the modified zero-valent iron, electron shuttle, and biostimulant, the purification and removal of the DNAPL phase and oil pollutants in the water can be achieved based on the synergistic effect of reductive dechlorination and microbial anaerobic degradation.

[0082] A second aspect of the present invention provides a method for preparing a self-identifying remediation material for heavy non-aqueous pollutants, the method comprising the following steps:

[0083] S1: Modified zero-valent iron, electron shuttle, biostimulant material and first binder are mixed and then granulated to obtain the core;

[0084] S2; The deoxidizer, the second binder and the core are mixed and then granulated to form an intermediate layer on the surface of the core;

[0085] S3: Heat the fat-soluble material to obtain a coating solution, and use the coating solution to coat the material obtained in step S2 to form a coating layer on the surface of the intermediate layer.

[0086] In a preferred embodiment, step S1 specifically includes: in the presence of a protective gas, modified zero-valent iron, an electron shuttle, a biostimulant material, and a first binder are mixed in a mixing granulator, then ethanol is added and mixing continues, and then the temperature is raised to 50°C in a uniform programmed heating manner to gradually complete granulation.

[0087] In this invention, adding ethanol during the granulation process in step S1 facilitates thorough mixing of the raw materials.

[0088] More preferably, in step S1, the amount of ethanol used is 30-50% by weight of the total weight of the modified zero-valent iron, the electron shuttle, the biostimulant material, and the first adhesive.

[0089] In a preferred embodiment, in step S1, the total weight of modified zero-valent iron, electron shuttle, biostimulant material and first adhesive is 100%, the content of modified zero-valent iron is 40-60% by weight, the content of electron shuttle is 10-20% by weight, the content of biostimulant material is 10-40% by weight, and the content of adhesive is 5-15% by weight.

[0090] More preferably, in step S1, the total weight of modified zero-valent iron, electron shuttle, biostimulant material and first adhesive is 100%, the content of modified zero-valent iron is 45-55% by weight, the content of electron shuttle is 12-16% by weight, the content of biostimulant material is 20-35% by weight, and the content of first adhesive is 7-12% by weight.

[0091] More preferably, the modified zero-valent iron is selected from one or more of polyethylene glycol modified zero-valent iron, carboxymethyl cellulose modified zero-valent iron, and sodium oleate modified zero-valent iron.

[0092] More preferably, the electron shuttle is selected from sodium anthraquinone-2,6-disulfonate and / or riboflavin.

[0093] More preferably, the biostimulant material is selected from one or more of yeast extract, nitrogen source, and phosphorus source.

[0094] More preferably, the nitrogen source is selected from ammonium chloride and / or potassium nitrate; the phosphorus source is selected from disodium hydrogen phosphate and / or potassium dihydrogen phosphate.

[0095] In a preferred embodiment, when the biostimulant is yeast extract, nitrogen source and phosphorus source, the weight ratio of the three is 10-16:8-13:1-3.

[0096] More preferably, the first adhesive can be an adhesive conventionally used in the art. In one specific embodiment, the first adhesive is polyvinylpyrrolidone.

[0097] In a preferred embodiment, in step S1, the kernel is spherical in shape.

[0098] In a preferred embodiment, the particle size of the core is 20-35 μm; specifically, it can be 20 μm, 25 μm, 30 μm or 35 μm.

[0099] In a preferred embodiment, step S2 specifically includes: mixing the deoxidizer, the second binder and ethanol to obtain a mixture, adding the mixture to the mixing granulator used in step S1 and mixing it with the core obtained in step S1 to form an intermediate layer on the surface of the core.

[0100] In a preferred embodiment, in step S2, the deoxidizing agent is selected from one or more of sodium sulfite, ascorbic acid, and glucose oxidase.

[0101] More preferably, the weight ratio of the deoxidizer to the second adhesive is 5-8:1.

[0102] More preferably, the second adhesive can be an adhesive conventionally used in the art. In one specific embodiment, the second adhesive is polyvinylpyrrolidone.

[0103] In a preferred embodiment, in step S2, the ratio of the total weight of the deoxidizer and the second adhesive to the weight of the core is 1:2-3.

[0104] In a preferred embodiment, in step S2, the amount of ethanol used is 20-40% by weight of the total weight of the deoxidizer and the second adhesive.

[0105] In a preferred embodiment, in step S2, the thickness of the intermediate layer is 5-10 μm.

[0106] In the method described in this invention, there are no special requirements for granulation in steps S1 and S2, and conventional granulation methods in the art can be used.

[0107] In a preferred embodiment, step S3 specifically includes:

[0108] The fat-soluble material is heated to obtain a coating solution. The material obtained in step S2 is placed in a preheated fluidized bed coating machine, and then the coating solution is sprayed in for coating. Then, it is dried.

[0109] In a preferred embodiment, in step S3, the volume ratio of the coating liquid to the material obtained in step S2 is 1:2-5.

[0110] In a preferred embodiment, in step S3, the thickness of the coating layer is 10-20 μm.

[0111] In a preferred embodiment, in step S3, the fat-soluble material is selected from fatty acids and / or paraffin.

[0112] More preferably, the fatty acid is selected from C16-C20 fatty acids.

[0113] In a preferred embodiment, the preheating temperature is 70-80°C.

[0114] In a preferred embodiment, the heating temperature is 80-90°C.

[0115] In a preferred embodiment, the drying temperature is 30-40°C and the time is 1-2 hours.

[0116] A third aspect of the present invention provides a self-identifying and remediating material for heavy non-aqueous phase pollutants prepared by the method described above.

[0117] The fourth aspect of this invention provides the application of the self-identifying remediation material for heavy non-aqueous pollutants described above in the remediation of heavy non-aqueous pollutants.

[0118] The self-identifying remediation material described in this invention can be injected into the target contaminated area or diffusion area of ​​chlorinated hydrocarbon DNAPL phase contaminants using an in-situ high-pressure injection method; it can also be used as a filling material to fill the bottom of the permeable reactive wall in a chlorinated hydrocarbon contaminated site; and it can also be used as a complementary material for in-situ extraction treatment, injected into the DNAPL phase rebound area in the later stage of extraction treatment.

[0119] The present invention will be described in detail below through embodiments, but the scope of protection of the present invention is not limited thereto.

[0120] Unless otherwise specified, all other reagents used in the following examples and comparative examples are commercially available products.

[0121] Example 1

[0122] S1: In the presence of a protective gas (nitrogen), modified zero-valent iron (polyethylene glycol modified zero-valent iron), electron shuttle (sodium anthraquinone-2,6-disulfonate), biostimulant (yeast extract, ammonium chloride, and potassium dihydrogen phosphate) and first binder (polyvinylpyrrolidone) are mixed in a granulator, then ethanol is added and mixing continues. Granulation is then completed at 50°C and 150 rpm to obtain a core with a diameter of 25 μm. The total weight of modified zero-valent iron, electron shuttle, biostimulant, and first binder is 100% by weight, the content of modified zero-valent iron is 47% by weight, the content of electron shuttle is 15% by weight, the content of biostimulant is 26% by weight, and the content of binder is 12% by weight. The weight ratio of yeast extract, nitrogen source (ammonium chloride), and phosphorus source (potassium dihydrogen phosphate) is 13:10:3. The amount of ethanol used is 40% by weight of the total weight of modified zero-valent iron, electron shuttle, biostimulant, and first binder.

[0123] S2: The deoxidizer (sodium sulfite), the second binder (polyvinylpyrrolidone), and ethanol are mixed to obtain a mixture. The mixture is added to the mixing granulator used in step S1 and mixed with the core obtained in step S1 for granulation. The mixing and granulation speed is 500 rpm and the granulation temperature is 50°C. An intermediate layer is formed on the surface of the core with a thickness of 6 μm. The weight ratio of the deoxidizer and the second binder is 6:1. The weight ratio of the total weight of the deoxidizer and the second binder to the weight of the core obtained in step S1 is 1:3. The amount of ethanol used is 30% by weight of the total weight of the deoxidizer and the second binder.

[0124] S3: Heat the fat-soluble material (paraffin) to 90°C to obtain a coating solution. Place the material obtained in step S2 into a fluidized bed coating machine preheated to 75°C, and then spray it with the coating solution for coating. Then dry it at 35°C for 2 hours to form a coating layer on the surface of the intermediate layer. The thickness of the coating layer is 12 μm. The volume ratio of the coating solution to the material obtained in step S2 is 1:4.

[0125] Example 2

[0126] S1: In the presence of a protective gas (nitrogen), modified zero-valent iron (polyethylene glycol modified zero-valent iron), electron shuttle (sodium anthraquinone-2,6-disulfonate), biostimulant (yeast extract, ammonium chloride, and potassium dihydrogen phosphate), and first binder (polyvinylpyrrolidone) are mixed in a granulator. Ethanol is then added and mixing continues. Granulation is then completed at 150 rpm and 50°C to obtain a core with a diameter of 25 μm. The total weight of modified zero-valent iron, electron shuttle, biostimulant, and first binder is 100% by weight, the content of modified zero-valent iron is 47% by weight, the content of electron shuttle is 15% by weight, the content of biostimulant is 26% by weight, and the content of binder is 12% by weight. The weight ratio of yeast extract, nitrogen source (ammonium chloride), and phosphorus source (potassium dihydrogen phosphate) is 13:10:3. The amount of ethanol used is 40% by weight of the total weight of modified zero-valent iron, electron shuttle, biostimulant, and first binder.

[0127] S2: The deoxidizer (sodium sulfite), the second binder (polyvinylpyrrolidone), and ethanol are mixed to obtain a mixture. The mixture is then added to the mixing granulator used in step S1 and mixed with the core obtained in step S1 for granulation. The granulation is carried out at 600 rpm and 50°C to form an intermediate layer on the surface of the core with a thickness of 6 μm. The weight ratio of the deoxidizer to the second binder is 7:1. The weight ratio of the total weight of the deoxidizer and the second binder to the weight of the core obtained in step S1 is 1:3. The amount of ethanol used is 30% by weight of the total weight of the deoxidizer and the second binder.

[0128] S3: Heat the fat-soluble material (paraffin) to 90°C to obtain a coating solution. Place the material obtained in step S2 into a fluidized bed coating machine preheated to 75°C, and then spray it with the coating solution for coating. Then dry it at 35°C for 2 hours to form a coating layer on the surface of the intermediate layer. The thickness of the coating layer is 10 μm. The volume ratio of the coating solution to the material obtained in step S2 is 1:5.

[0129] Example 3

[0130] S1: In the presence of a protective gas (nitrogen), modified zero-valent iron (polyethylene glycol modified zero-valent iron), electron shuttle (sodium anthraquinone-2,6-disulfonate), biostimulant (yeast extract, ammonium chloride, and potassium dihydrogen phosphate) and first binder (polyvinylpyrrolidone) are mixed in a granulator, then ethanol is added and mixing continues. Granulation is then completed at 200 rpm and 50°C to obtain a core with a diameter of 25 μm. The total weight of modified zero-valent iron, electron shuttle, biostimulant, and first binder is 100% by weight, the content of modified zero-valent iron is 47% by weight, the content of electron shuttle is 15% by weight, the content of biostimulant is 26% by weight, and the content of binder is 12% by weight. The weight ratio of yeast extract, nitrogen source (ammonium chloride), and phosphorus source (potassium dihydrogen phosphate) is 13:10:3. The amount of ethanol used is 40% by weight of the total weight of modified zero-valent iron, electron shuttle, biostimulant, and first binder.

[0131] S2: The deoxidizer (ascorbic acid), the second binder (polyvinylpyrrolidone), and ethanol are mixed to obtain a mixture. The mixture is then added to the mixing granulator used in step S1 and mixed with the core obtained in step S1 for granulation. The granulation is carried out at 600 rpm and 50°C to form an intermediate layer on the surface of the core with a thickness of 5 μm. The weight ratio of the deoxidizer to the second binder is 6:1. The weight ratio of the total weight of the deoxidizer and the second binder to the weight of the core obtained in step S1 is 1:3. The amount of ethanol used is 30% by weight of the total weight of the deoxidizer and the second binder.

[0132] S3: Heat the fat-soluble material (paraffin and stearic acid in a weight ratio of 1:1) to 90°C to obtain a coating solution. Place the material obtained in step S2 into a fluidized bed coating machine preheated to 75°C, and then spray it with the coating solution for coating. Then dry it at 35°C for 2 hours to form a coating layer on the surface of the intermediate layer. The thickness of the coating layer is 13 μm. The volume ratio of the coating solution to the material obtained in step S2 is 1:4.

[0133] Example 4

[0134] S1: In the presence of a protective gas (nitrogen), modified zero-valent iron (polyethylene glycol modified zero-valent iron), electron shuttle (riboflavin), biostimulant (yeast extract, ammonium chloride, and potassium dihydrogen phosphate), and first binder (polyvinylpyrrolidone) are mixed in a granulator. Ethanol is then added and mixing continues. Granulation is then completed at 150 rpm and 50°C to obtain a core with a diameter of 25 μm. The total weight of modified zero-valent iron, electron shuttle, biostimulant, and first binder is 100% by weight, the content of modified zero-valent iron is 47% by weight, the content of electron shuttle is 15% by weight, the content of biostimulant is 26% by weight, and the content of binder is 12% by weight. The weight ratio of yeast extract, nitrogen source (ammonium chloride), and phosphorus source (potassium dihydrogen phosphate) is 13:10:3. The amount of ethanol used is 40% by weight of the total weight of modified zero-valent iron, electron shuttle, biostimulant, and first binder.

[0135] S2: The deoxidizer (sodium sulfite), the second binder (polyvinylpyrrolidone), and ethanol are mixed to obtain a mixture. The mixture is then added to the mixing granulator used in step S1 and mixed with the core obtained in step S1 for granulation. The mixing and granulation speed is 600 rpm and the granulation temperature is 50°C. An intermediate layer with a thickness of 6 μm is formed on the surface of the core. The weight ratio of the deoxidizer and the second binder is 7:1. The weight ratio of the total weight of the deoxidizer and the second binder to the weight of the core obtained in step S1 is 1:3. The amount of ethanol used is 30% by weight of the total weight of the deoxidizer and the second binder.

[0136] S3: Heat the fat-soluble material (stearic acid) to 90°C to obtain a coating solution. Place the material obtained in step S2 into a fluidized bed coating machine preheated to 75°C, and then spray it with the coating solution for coating. Then dry it at 35°C for 2 hours to form a coating layer on the surface of the intermediate layer. The thickness of the coating layer is 11 μm. The volume ratio of the coating solution to the material obtained in step S2 is 1:5.

[0137] Example 5

[0138] S1: In the presence of a protective gas (nitrogen), modified zero-valent iron (carboxymethyl cellulose modified zero-valent iron), electron shuttle (anthraquinone-2,6-disulfonate sodium), biostimulant (yeast extract, potassium nitrate, and disodium hydrogen phosphate), and first binder (polyvinylpyrrolidone) are mixed in a granulator. Ethanol is then added and mixing continues. Granulation is then completed at 150 rpm and 50°C to obtain a core with a diameter of 23 μm. The total weight of modified zero-valent iron, electron shuttle, biostimulant, and first binder is 100% by weight, the content of modified zero-valent iron is 50% by weight, the content of electron shuttle is 12% by weight, the content of biostimulant is 29% by weight, and the content of binder is 9% by weight. The weight ratio of yeast extract, nitrogen source (potassium nitrate), and phosphorus source (disodium hydrogen phosphate) is 15:12:2. The amount of ethanol used is 40% by weight of the total weight of modified zero-valent iron, electron shuttle, biostimulant, and first binder.

[0139] S2: The deoxidizer (sodium sulfite), the second binder (polyvinylpyrrolidone), and ethanol are mixed to obtain a mixture. The mixture is then added to the mixing granulator used in step S1 and mixed with the core obtained in step S1 for granulation. The mixing and granulation speed is 600 rpm and the granulation temperature is 50°C. An intermediate layer is formed on the surface of the core with a thickness of 8 μm. The weight ratio of the deoxidizer and the second binder is 6:1. The weight ratio of the total weight of the deoxidizer and the second binder to the weight of the core obtained in step S1 is 1:3. The amount of ethanol used is 30% by weight of the total weight of the deoxidizer and the second binder.

[0140] S3: Heat the fat-soluble material (paraffin) to 90°C to obtain a coating solution. Place the material obtained in step S2 into a fluidized bed coating machine preheated to 75°C, and then spray it with the coating solution for coating. Then dry it at 35°C for 2 hours to form a coating layer on the surface of the intermediate layer. The thickness of the coating layer is 12 μm. The volume ratio of the coating solution to the material obtained in step S2 is 1:4.

[0141] Example 6

[0142] S1: In the presence of a protective gas (nitrogen), modified zero-valent iron (carboxymethyl cellulose modified zero-valent iron), electron shuttle (riboflavin), biostimulant (yeast extract, potassium nitrate, and disodium hydrogen phosphate), and first binder (polyvinylpyrrolidone) are mixed in a granulator. Ethanol is then added and mixing continues. Granulation is then completed at 200 rpm and 50°C to obtain a core with a diameter of 25 μm. The total weight of modified zero-valent iron, electron shuttle, biostimulant, and first binder is 100% by weight, the content of modified zero-valent iron is 50% by weight, the content of electron shuttle is 12% by weight, the content of biostimulant is 29% by weight, and the content of binder is 9% by weight. The weight ratio of yeast extract, nitrogen source (potassium nitrate), and phosphorus source (disodium hydrogen phosphate) is 15:12:2. The amount of ethanol used is 40% by weight of the total weight of modified zero-valent iron, electron shuttle, biostimulant, and first binder.

[0143] S2: The deoxidizer (sodium sulfite), the second binder (polyvinylpyrrolidone), and ethanol are mixed to obtain a mixture. The mixture is then added to the mixing granulator used in step S1 and mixed with the core obtained in step S1 for granulation. The mixing and granulation speed is 600 rpm and the granulation temperature is 50°C. An intermediate layer is formed on the surface of the core with a thickness of 8 μm. The weight ratio of the deoxidizer and the second binder is 6:1. The weight ratio of the total weight of the deoxidizer and the second binder to the weight of the core obtained in step S1 is 1:3. The amount of ethanol used is 30% by weight of the total weight of the deoxidizer and the second binder.

[0144] S3: Heat the fat-soluble material (paraffin) to 90°C to obtain a coating solution. Place the material obtained in step S2 into a fluidized bed coating machine preheated to 75°C, and then spray it with the coating solution for coating. Then dry it at 35°C for 2 hours to form a coating layer on the surface of the intermediate layer. The thickness of the coating layer is 12 μm. The volume ratio of the coating solution to the material obtained in step S2 is 1:4.

[0145] Example 7

[0146] S1: In the presence of a protective gas (nitrogen), modified zero-valent iron (carboxymethyl cellulose modified zero-valent iron), electron shuttle (anthraquinone-2,6-disulfonate sodium), biostimulant (yeast extract, potassium nitrate, and disodium hydrogen phosphate), and first binder (polyvinylpyrrolidone) are mixed in a granulator. Ethanol is then added and mixing continues. Granulation is then completed at 200 rpm and 50°C to obtain a core with a diameter of 23 μm. The total weight of modified zero-valent iron, electron shuttle, biostimulant, and first binder is 100% by weight, the content of modified zero-valent iron is 50% by weight, the content of electron shuttle is 12% by weight, the content of biostimulant is 29% by weight, and the content of binder is 9% by weight. The weight ratio of yeast extract, nitrogen source (potassium nitrate), and phosphorus source (disodium hydrogen phosphate) is 15:12:2. The amount of ethanol used is 40% by weight of the total weight of modified zero-valent iron, electron shuttle, biostimulant, and first binder.

[0147] S2: The deoxidizer (sodium sulfite), the second binder (polyvinylpyrrolidone), and ethanol are mixed to obtain a mixture. The mixture is then added to the mixing granulator used in step S1 and mixed with the core obtained in step S1 for granulation. The mixing and granulation speed is 600 rpm and the granulation temperature is 50°C. An intermediate layer is formed on the surface of the core with a thickness of 8 μm. The weight ratio of the deoxidizer and the second binder is 6:1. The weight ratio of the total weight of the deoxidizer and the second binder to the weight of the core obtained in step S1 is 1:3. The amount of ethanol used is 30% by weight of the total weight of the deoxidizer and the second binder.

[0148] S3: Heat the fat-soluble material (paraffin and stearic acid in a weight ratio of 1:1) to 90°C to obtain a coating solution. Place the material obtained in step S2 into a fluidized bed coating machine preheated to 75°C, and then spray it with the coating solution for coating. Then dry it at 35°C for 2 hours to form a coating layer on the surface of the intermediate layer. The thickness of the coating layer is 13 μm. The volume ratio of the coating solution to the material obtained in step S2 is 1:4.

[0149] Example 8

[0150] S1: In the presence of a protective gas (nitrogen), modified zero-valent iron (sodium oleate modified zero-valent iron), electron shuttle (sodium anthraquinone-2,6-disulfonate), biostimulant (yeast extract, potassium nitrate, and disodium hydrogen phosphate), and first binder (polyvinylpyrrolidone) are mixed in a granulator. Ethanol is then added and mixing continues. Granulation is then completed at 150 rpm and 50°C to obtain a core with a diameter of 28 μm. The total weight of modified zero-valent iron, electron shuttle, biostimulant, and first binder is 100% by weight, the content of modified zero-valent iron is 48% by weight, the content of electron shuttle is 14% by weight, the content of biostimulant is 26% by weight, and the content of binder is 12% by weight. The weight ratio of yeast extract, nitrogen source (potassium nitrate), and phosphorus source (disodium hydrogen phosphate) is 12:12:2. The amount of ethanol used is 40% by weight of the total weight of modified zero-valent iron, electron shuttle, biostimulant, and first binder.

[0151] S2: The deoxidizer (sodium sulfite), the second binder (polyvinylpyrrolidone), and ethanol are mixed to obtain a mixture. The mixture is then added to the mixing granulator used in step S1 and mixed with the core obtained in step S1 for granulation. The mixing and granulation speed is 600 rpm, and the granulation temperature is 50°C to form an intermediate layer on the surface of the core. The thickness of the intermediate layer is 7 μm. The weight ratio of the deoxidizer and the second binder is 7:1. The weight ratio of the total weight of the deoxidizer and the second binder to the weight of the core obtained in step S1 is 1:3. The amount of ethanol used is 30% by weight of the total weight of the deoxidizer and the second binder.

[0152] S3: Heat the fat-soluble material (paraffin) to 90°C to obtain a coating solution. Place the material obtained in step S2 into a fluidized bed coating machine preheated to 75°C, and then spray it with the coating solution for coating. Then dry it at 4°C for 2 hours to form a coating layer on the surface of the intermediate layer. The thickness of the coating layer is 10 μm. The volume ratio of the coating solution to the material obtained in step S2 is 1:4.5.

[0153] Example 9

[0154] S1: In the presence of a protective gas (nitrogen), modified zero-valent iron (sodium oleate modified zero-valent iron), electron shuttle (riboflavin), biostimulant (yeast extract, potassium nitrate, and disodium hydrogen phosphate), and first binder (polyvinylpyrrolidone) are mixed in a granulator. Ethanol is then added and mixing continues. Granulation is then completed at 150 rpm and 50°C to obtain a core with a diameter of 30 μm. The total weight of modified zero-valent iron, electron shuttle, biostimulant, and first binder is 100% by weight, the content of modified zero-valent iron is 48% by weight, the content of electron shuttle is 14% by weight, the content of biostimulant is 26% by weight, and the content of binder is 12% by weight. The weight ratio of yeast extract, nitrogen source (potassium nitrate), and phosphorus source (disodium hydrogen phosphate) is 12:12:2. The amount of ethanol used is 40% by weight of the total weight of modified zero-valent iron, electron shuttle, biostimulant, and first binder.

[0155] S2: The deoxidizer (sodium sulfite), the second binder (polyvinylpyrrolidone), and ethanol are mixed to obtain a mixture. The mixture is then added to the mixing granulator used in step S1 and mixed with the core obtained in step S1 for granulation. The mixing and granulation speed is 500 rpm and the granulation temperature is 50°C. An intermediate layer with a thickness of 7 μm is formed on the surface of the core. The weight ratio of the deoxidizer and the second binder is 7:1. The weight ratio of the total weight of the deoxidizer and the second binder to the weight of the core obtained in step S1 is 1:3. The amount of ethanol used is 30% by weight of the total weight of the deoxidizer and the second binder.

[0156] S3: Heat the fat-soluble material (paraffin) to 90°C to obtain a coating solution. Place the material obtained in step S2 into a fluidized bed coating machine preheated to 75°C, and then spray it with the coating solution for coating. Then dry it at 40°C for 1 hour to form a coating layer on the surface of the intermediate layer. The thickness of the coating layer is 10 μm. The volume ratio of the coating solution to the material obtained in step S2 is 1:4.5.

[0157] Example 10

[0158] S1: In the presence of a protective gas (nitrogen), modified zero-valent iron (sodium oleate modified zero-valent iron), electron shuttle (riboflavin), biostimulant (yeast extract, potassium nitrate, and disodium hydrogen phosphate), and first binder (polyvinylpyrrolidone) are mixed in a granulator. Ethanol is then added and mixing continues. Granulation is then completed at 150 rpm and 50°C to obtain a core with a diameter of 28 μm. The total weight of modified zero-valent iron, electron shuttle, biostimulant, and first binder is 100% by weight, the content of modified zero-valent iron is 48% by weight, the content of electron shuttle is 14% by weight, the content of biostimulant is 26% by weight, and the content of binder is 12% by weight. The weight ratio of yeast extract, nitrogen source (potassium nitrate), and phosphorus source (disodium hydrogen phosphate) is 12:12:2. The amount of ethanol used is 40% by weight of the total weight of modified zero-valent iron, electron shuttle, biostimulant, and first binder.

[0159] S2: The deoxidizer (sodium sulfite), the second binder (polyvinylpyrrolidone), and ethanol are mixed to obtain a mixture. The mixture is then added to the mixing granulator used in step S1 and mixed with the core obtained in step S1 for granulation. The mixing and granulation speed is 500 rpm and the granulation temperature is 50°C. An intermediate layer with a thickness of 7 μm is formed on the surface of the core. The weight ratio of the deoxidizer and the second binder is 7:1. The weight ratio of the total weight of the deoxidizer and the second binder to the weight of the core obtained in step S1 is 1:3. The amount of ethanol used is 30% by weight of the total weight of the deoxidizer and the second binder.

[0160] S3: Heat the fat-soluble material (paraffin and stearic acid in a weight ratio of 1:1) to 90°C to obtain a coating solution. Place the material obtained in step S2 into a fluidized bed coating machine preheated to 75°C, and then spray it with the coating solution for coating. Then dry it at 40°C for 1 hour to form a coating layer on the surface of the intermediate layer. The thickness of the coating layer is 12 μm. The volume ratio of the coating solution to the material obtained in step S2 is 1:4.5.

[0161] Comparative Example 1

[0162] The method described in Example 5 is implemented, except that step S3 is omitted.

[0163] Comparative Example 2

[0164] The method described in Example 5 is implemented, except that steps S2 and S3 are omitted.

[0165] Comparative Example 3

[0166] S1: In the presence of a protective gas (nitrogen), modified zero-valent iron (carboxymethyl cellulose modified zero-valent iron), biostimulant (yeast extract, potassium nitrate, and disodium hydrogen phosphate), and first binder (polyvinylpyrrolidone) are mixed in a granulator. Ethanol is then added and mixing continues. Granulation is then completed at 150 rpm and 50°C to obtain a core with a diameter of 22 μm. The total weight of modified zero-valent iron, biostimulant, and first binder is 100% by weight, the content of modified zero-valent iron is 55% by weight, the content of biostimulant is 35% by weight, and the content of binder is 10% by weight. The weight ratio of yeast extract, nitrogen source (potassium nitrate), and phosphorus source (disodium hydrogen phosphate) is 18:13:4. The amount of ethanol used is 40% by weight of the total weight of modified zero-valent iron, biostimulant, and first binder.

[0167] S2: The deoxidizer (sodium sulfite), the second binder (polyvinylpyrrolidone), and ethanol are mixed to obtain a mixture. The mixture is then added to the mixing granulator used in step S1 and mixed with the core obtained in step S1 for granulation. The mixing and granulation speed is 600 rpm and the granulation temperature is 50°C. An intermediate layer is formed on the surface of the core with a thickness of 8 μm. The weight ratio of the deoxidizer and the second binder is 6:1. The weight ratio of the total weight of the deoxidizer and the second binder to the weight of the core obtained in step S1 is 1:3. The amount of ethanol used is 30% by weight of the total weight of the deoxidizer and the second binder.

[0168] S3: Heat the fat-soluble material (paraffin) to 90°C to obtain a coating solution. Place the material obtained in step S2 into a fluidized bed coating machine preheated to 75°C, and then spray it with the coating solution for coating. Then dry it at 35°C for 2 hours to form a coating layer on the surface of the intermediate layer. The thickness of the coating layer is 12 μm. The volume ratio of the coating solution to the material obtained in step S2 is 1:4.

[0169] Test Example 1

[0170] The properties of the products prepared in Examples 1-10 and Comparative Example 3 were tested, and the test results are shown in Table 1. The test methods are as follows:

[0171] Add the sample to be tested into a glass beaker containing 1L of tap water and stir with a glass rod for 10 minutes daily. After 15 days, test the iron ion concentration and chloride ion concentration in the water. Then, add 5mL of trichloroethylene to the bottom of the beaker to form DNAPL. Continue to let it stand for 3 days and then test the chloride ion content.

[0172] The properties of the products prepared in Comparative Examples 1-2 were tested, and the results are shown in Table 2. The testing methods are as follows:

[0173] The sample to be tested was added to a glass beaker containing 1L of tap water and stirred with a glass rod for 10 minutes daily. After 3 days, the iron ion concentration in the water was measured, and the initial chloride ion concentration in the water was also measured. Then, 5mL of trichloroethylene was added to the bottom of the beaker to form DNAPL. After 3 more days, the chloride ion content was measured.

[0174] Table 1

[0175] Example 1 10g <0.2mg / L 0.47 mg / L 2415mg / L Example 2 10g <0.2mg / L 0.43 mg / L 2372mg / L Example 3 10g <0.2mg / L 0.37 mg / L 2504mg / L Example 4 10g <0.2mg / L 0.58 mg / L 2351mg / L Example 5 10g <0.2mg / L 0.51 mg / L 2460mg / L Example 6 10g <0.2mg / L 0.41 mg / L 2372mg / L Example 7 10g <0.2mg / L 0.48 mg / L 2575mg / L Example 8 10g <0.2mg / L 0.46 mg / L 2419mg / L Example 9 10g <0.2mg / L 0.47 mg / L 2085mg / L Example 10 10g <0.2mg / L 0.51 mg / L 2605mg / L Comparative Example 3 10g <0.2mg / L 0.39 mg / L 1508mg / L

[0176] Table 2

[0177] Comparative Example 1 9g 31mg / L 0.47 mg / L 672mg / L Comparative Example 2 7g 95mg / L 0.47 mg / L 71mg / L

[0178] During the performance testing of the products prepared in Examples 1-10 and Comparative Example 3, after the addition of trichloroethylene, it was immediately observed that the test samples dissolved and broke down successively, and the turbidity of the water in the beaker gradually increased, presenting a brownish-green turbidity. Combined with the data in Table 1, it can be seen that the products prepared in the examples can achieve specific self-recognition of chlorinated hydrocarbon DNAPL phase pollutants and can efficiently remove chlorine from trichloroethylene. Although the product prepared in Comparative Example 3 can recognize chlorinated hydrocarbons, its dechlorination ability is relatively low.

[0179] During the performance testing of the product prepared in Comparative Example 1, the sample was added to tap water and stirred for 3 days. It was observed that some of the sample remained suspended in the tap water, and the iron ion concentration in the water increased rapidly. Combined with the data in Table 2, it can be seen that the product prepared in Comparative Example 1 has low dechlorination capacity and exhibits some loss of zero-valent iron.

[0180] During the performance testing of the product prepared in Comparative Example 2, the sample was added to tap water and stirred for 3 days. It was observed that some of the sample remained suspended in the tap water, and the iron ion concentration in the water increased rapidly. Combined with the data in Table 2, it can be seen that the product prepared in Comparative Example 2 can only remove a small amount of chlorine, and the loss of zero-valent iron is significant.

[0181] Application Example 1

[0182] The application site is a petrochemical contaminated site, primarily engaged in modern chemical production, manufacturing various aldehydes, epoxy compounds, butyl rubber, plasticizers, and acetonitrile series. Preliminary site investigations indicated that groundwater contaminants included polycyclic aromatic hydrocarbons, phenols, and chlorinated hydrocarbons. The site covers a total area of ​​0.7 km². 2 The groundwater level is consistently between 1.8 and 3 meters deep. The soil layers, from top to bottom, consist of fill, silt, clay, and bedrock. The first impermeable slab is at a depth of 6 to 9 meters, and the groundwater permeability coefficient is 3.8 × 10⁻⁶. -6The area has a high elevation difference, making it prone to pollution migration due to seasonal rainfall. Two wells detected DNAPL-phase contaminants of chlorinated hydrocarbons near the aquitard. Ground-penetrating radar was used to delineate the DNAPL-phase contamination area of ​​chlorinated hydrocarbons. The contaminated area of ​​monitoring well A was approximately 37 m². 2 Using the product prepared in Example 3, direct-push differential pressure injection was conducted at 20 points in monitoring well A, with an injection volume of 10 kg at each point and an injection depth of 8–8.5 m. Chloride ion concentration changes were then continuously observed in monitoring well A. During 107 days of monitoring, the chloride ion concentration continuously increased, with a rapid increase in the early stages, reaching 1300 mg / L on day 30 and 2100 mg / L on day 107. Ground-penetrating radar was used to detect changes in the DNAPL phase chlorinated hydrocarbon contamination area, showing a 78% reduction in the DNAPL phase area.

[0183] Application Example 2

[0184] The application site was a petrochemical contaminated site, primarily used for oil refining and chemical production, producing refined oil products, cyclohexane, and allyl chloride. Preliminary site investigation revealed the presence of complex contaminants such as LNAPL and DNAPL. Multiphase extraction remediation technology was selected for this site, with a total of 11,428 m³ extracted. 3 After the contaminated groundwater was pumped out and treated, approximately 10 meters of water remained at the impermeable slab of the contaminated source. 2 The product exhibited repeated tailing and precipitation of small-scale chlorinated hydrocarbon DNAPL phases. To address this issue, five injection points were established in this localized area. 20 kg of the product prepared in Example 10 was injected at each point at a pressure of 0.8–1 MPa at the impermeable base plate, and monitoring was conducted continuously after injection. The chloride ion concentration increased from an initial 27 mg / L to 1307 mg / L within 83 days, indicating a significant dechlorination effect. No significant DNAPL phase chlorinated hydrocarbon contaminants were detected after day 68.

[0185] 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 self-identifying and remediating material for heavy non-aqueous pollutants, characterized in that, The heavy non-aqueous pollutant self-identification and remediation material has a multi-core-shell structure, which has a core (3), an intermediate layer (2) and a coating layer (1) distributed from the inside to the outside. The core (3) contains modified zero-valent iron, an electron shuttle, and a biostimulant; the modified zero-valent iron is selected from one or more of polyethylene glycol modified zero-valent iron, carboxymethyl cellulose modified zero-valent iron, and sodium oleate modified zero-valent iron; the electron shuttle is selected from sodium anthraquinone-2,6-disulfonate and / or riboflavin; the biostimulant is selected from one or more of yeast extract, nitrogen source, and phosphorus source. The intermediate layer (2) contains a deoxidizing agent; the deoxidizing agent is selected from one or more of sodium sulfite, ascorbic acid and glucose oxidase; The coating layer (1) contains a fat-soluble material; the fat-soluble material is selected from fatty acids and / or paraffin.

2. The self-identification and remediation material for heavy non-aqueous pollutants according to claim 1, characterized in that, The particle size of the kernel (3) is 20-35 μm.

3. The self-identification and remediation material for heavy non-aqueous pollutants according to claim 1 or 2, characterized in that, The core (3) also contains a first adhesive.

4. The self-identification and remediation material for heavy non-aqueous pollutants according to claim 3, characterized in that, The total weight of modified zero-valent iron, electron shuttle, biostimulant material and first adhesive is 100% by weight, wherein the content of modified zero-valent iron is 40-60% by weight, the content of electron shuttle is 10-20% by weight, the content of biostimulant material is 10-40% by weight, and the content of first adhesive is 5-15% by weight.

5. The self-identification and remediation material for heavy non-aqueous pollutants according to claim 1, characterized in that, The thickness of the intermediate layer (2) is 5-10 μm.

6. The self-identification and remediation material for heavy non-aqueous pollutants according to claim 1, characterized in that, The intermediate layer (2) also contains a second adhesive.

7. The self-identification and remediation material for heavy non-aqueous pollutants according to claim 1, characterized in that, The thickness of the coating layer (1) is 10-20 μm.

8. The self-identification and remediation material for heavy non-aqueous pollutants according to claim 1, characterized in that, The fatty acids are selected from C16-C20 fatty acids.

9. A method for preparing a self-identifying and remediating material for heavy non-aqueous phase pollutants according to any one of claims 1-8, characterized in that, The method includes the following steps: S1: Modified zero-valent iron, electron shuttle, biostimulant material and first binder are mixed and then granulated to obtain the core; S2; The deoxidizer, the second binder and the core are mixed and then granulated to form an intermediate layer on the surface of the core; S3: Heat the fat-soluble material to obtain a coating solution, and use the coating solution to coat the material obtained in step S2 to form a coating layer on the surface of the intermediate layer.

10. The method according to claim 9, characterized in that, In step S2, the ratio of the amount of the deoxidizer to the amount of the second adhesive is 5-8:

1.

11. The method according to claim 9, characterized in that, In step S2, the ratio of the total weight of the deoxidizer and the second adhesive to the weight of the core is 1:2-3.

12. The method according to claim 9, characterized in that, The specific process of step S3 includes: The fat-soluble material is heated to obtain a coating solution. The material obtained in step S2 is placed in a preheated fluidized bed coating machine, and then the coating solution is sprayed in for coating. Then, it is dried.

13. The method according to claim 9, characterized in that, In step S3, the volume ratio of the coating solution to the material obtained in step S2 is 1:2-5.

14. The application of the self-identifying remediation material for heavy non-aqueous pollutants according to any one of claims 1-8 in the remediation of heavy non-aqueous pollutants.

Images