Intelligent complexing controlled-release soil remediation material and application thereof

Abstract

The invention belongs to the field of soil remediation, and discloses an intelligent complexing controlled-release soil remediation material and application thereof, the intelligent complexing controlled-release soil remediation material mainly comprises three parts: a response matrix, a recognition element and a remediation agent; the response matrix is selected from poly (N-isopropylacrylamide) hydrogel; the recognition element is made of thiolated chitosan; and the repairing agent is loaded with ethylene diamine tetraacetic acid disodium (ethylene diamine tetraacetic acid) (ethylene diamine tetraacetic acid (ethylene diamine tetraacetic acid)-2Na). Through a series of synergistic effects of specific recognition of the recognition element, signal transduction and structural change of the response matrix and release and remediation reaction of the remediation agent, intelligent and efficient remediation of the heavy metal pollutants in the soil is achieved.

Description

Technical Field

[0001] The present invention belongs to, but is not limited to, the technical field of soil remediation, and particularly relates to an intelligent complexing controlled-release soil remediation material and its application. Background Art

[0002] At present, with the rapid development of industrialization and urbanization, the problem of soil pollution is becoming increasingly serious. The situations of heavy metal pollution and excessive organic pollutants frequently occur in many places, seriously threatening the ecological environment safety and human health. Traditional soil remediation methods, such as physical separation method, chemical leaching method, and bioremediation method, although can alleviate the current situation of soil pollution to a certain extent, each has obvious limitations.

[0003] The physical separation method has extremely high requirements for equipment and can only treat pollutants with relatively large particles. For the fine particle pollutants and dissolved pollutants widely distributed in the soil, the treatment effect is not good; the chemical leaching method is prone to cause secondary pollution and will also damage the original structure and physical and chemical properties of the soil; although the bioremediation method is relatively environmentally friendly, the remediation cycle is long and it is greatly affected by environmental factors, making it difficult to meet the urgent need for rapid remediation.

[0004] Under this background, it is urgent to develop a new type of soil remediation material with high efficiency, environmental friendliness and strong adaptability. The intelligent complexing controlled-release remediation material emerges as the times require. By means of advanced materials science and technology, it is committed to realizing the accurate identification and efficient remediation of soil pollutants, and effectively overcoming the drawbacks of traditional remediation methods.

[0005] In view of the above analysis, the technical problems that urgently need to be solved in the existing technology are as follows:

[0006] (1) Precise remediation requirement: The types and degrees of soil pollution in different regions vary greatly. Traditional remediation methods often adopt a single mode and are difficult to achieve precise remediation. The intelligent complexing controlled-release remediation material can automatically adjust the remediation mechanism according to the types and concentrations of heavy metal pollutants in the soil, and conduct targeted remediation for different pollutants, greatly improving the remediation efficiency and effect.

[0007] (2) Environmental protection requirement: Traditional remediation methods may introduce new pollutants during the remediation process or cause irreversible damage to the soil ecosystem. The intelligent complexing controlled-release remediation material adopts a mild remediation method, minimizing the negative impact on the soil and the surrounding environment, which conforms to the current development concept of green environmental protection.

[0008] (3) Consideration of cost-benefit: In the long run, the intelligent complexing controlled-release remediation material has high remediation efficiency and short remediation cycle, which can reduce the long-term environmental governance cost and potential health risk cost. Through precise remediation, it avoids the waste of resources caused by over-remediation and realizes the maximization of cost-benefit.

[0009] (4) Sustainable development needs: Soil is a key resource for human survival. Ensuring the health and sustainable use of soil is the foundation for achieving sustainable development. The application of intelligent complexing controlled-release remediation materials helps to quickly restore the ecological functions of polluted soil, providing a solid soil foundation for agricultural production, ecological protection, etc., and strongly promoting the sustainable development of social economy. Summary of the Invention

[0010] In view of the problems existing in the prior art, the present invention provides an intelligent complexing controlled-release soil remediation material and its application.

[0011] The present invention is realized as follows. An intelligent complexing controlled-release soil remediation material, characterized in that the intelligent complexing controlled-release soil remediation material mainly consists of three parts: a responsive matrix, a recognition element, and a remediation agent; the responsive matrix is selected as poly(N-isopropylacrylamide) hydrogel; the recognition element is thiolated chitosan; the remediation agent is loaded with disodium ethylenediaminetetraacetate (EDTA-2Na).

[0012] Further, for the preparation of the responsive matrix, 10 g of N-isopropylacrylamide monomer, 0.05 g of N,N'-methylenebisacrylamide (crosslinking agent), and 0.03 g of ammonium persulfate (initiator) are added to 100 mL of deionized water. Under nitrogen protection, it is stirred and reacted at 60 °C for 4 - 6 hours to form a poly(N-isopropylacrylamide) hydrogel matrix.

[0013] Further, for the preparation of the recognition element, 5 g of chitosan is dissolved in 100 mL of 1% acetic acid solution, and 3 - 5 g of thiolation reagent (3-mercaptopropionic acid) is added. It is stirred and reacted at 40 - 50 °C for 6 - 8 hours to obtain thiolated chitosan, and then it is uniformly mixed into the above-prepared poly(N-isopropylacrylamide) hydrogel matrix.

[0014] Further, for the preparation of the remediation agent, the prepared hydrogel matrix containing the recognition element is immersed in a 0.5 mol / L EDTA-2Na solution for 12 - 24 hours, so that EDTA-2Na fully diffuses into the hydrogel network structure to complete the loading of the remediation agent. Finally, an intelligent complexing controlled-release remediation material is obtained. When encountering heavy metal ions in the soil, thiolated chitosan recognizes and binds to the heavy metal ions, triggering a structural change in the hydrogel matrix and releasing EDTA-2Na, which undergoes a chelation reaction with the heavy metal ions to achieve the purpose of soil remediation.

[0015] Further, for the intelligent complexing controlled-release soil remediation material, for slightly polluted soil, the material addition amount is generally 0.5% - 1% of the soil mass; for moderately polluted soil, the addition ratio can be increased to 1% - 3%; for severely polluted soil, the addition ratio is usually 3% - 5%.

[0016] Combined with the above technical solutions and the technical problems solved, the advantages and positive effects of the technical solutions to be protected by the present invention are as follows:

[0017] First, precise repair ability: Conventional repair agents often lack the specific recognition ability for different heavy metals and usually adopt a unified repair mechanism, making it difficult to precisely repair multiple heavy metals in complex contaminated soil. However, the intelligent complexing controlled-release repair material, with its unique recognition element - mercapto chitosan, can accurately identify different heavy metal ions such as lead, cadmium, mercury, and copper like a "molecular radar" and initiate corresponding repair mechanisms, greatly improving the pertinence and efficiency of the repair. When the intelligent complexing controlled-release repair material is added to the contaminated soil, the recognition element mercapto chitosan takes the lead in playing its role. Due to the special affinity of the mercapto groups on its molecular chain for heavy metal ions, it will actively search for and approach heavy metal ions in the soil solution. For example, in contaminated soil containing heavy metal ions such as lead and cadmium, mercapto chitosan will quickly undergo a complexation reaction with these heavy metal ions like a "hunter" with targeting ability. This reaction is highly specific, and different heavy metal ions will form complexes with specific structures with mercapto groups, just like different keys corresponding to different locks, thus achieving the precise recognition of different heavy metal ions. In addition, for some organic pollutants containing specific functional groups (such as carboxyl and amino groups), mercapto chitosan can also preliminarily recognize and adsorb them through intermolecular interactions such as hydrogen bonds and electrostatic interactions, while conventional repair agents cannot achieve such precise repair effects.

[0018] Intelligent response characteristics: Conventional remediation agents generally carry out remediation in a fixed reaction mode in the soil and are difficult to make timely adjustments according to changes in the soil environment. The response matrix of the intelligent complexing controlled-release remediation material, poly(N-isopropylacrylamide) hydrogel, is extremely sensitive to minor temperature and pH changes in the soil environment. When the soil environment changes, it can quickly undergo structural changes such as swelling or shrinking, thereby triggering the release of the remediation agent and achieving an intelligent response to changes in soil pollution conditions to ensure the efficient progress of the remediation process. After the recognition element captures heavy metal ions or interacts with organic pollutants, it will cause changes in the local microenvironment. Such changes may be manifested as changes in temperature, pH, or ionic strength in the micro-region. Poly(N-isopropylacrylamide) hydrogel, as the response matrix, is extremely sensitive to these minor environmental changes. For example, when heavy metal ions complex with mercaptochitosan, local hydrogen ions or hydroxide ions will be consumed, resulting in a change in pH. After poly(N-isopropylacrylamide) hydrogel senses the change in pH, its molecular chains will stretch or curl, causing the network structure of the hydrogel to swell or shrink. This structural change is like opening the "valve" of the hydrogel pores, causing the remediation agent sodium ethylenediaminetetraacetate (EDTA-2Na) loaded in the hydrogel network structure to start releasing from the pores. Moreover, the degree of environmental change is different, and the degree of structural change of the hydrogel is also different, thereby controlling the release amount of the remediation agent. If the concentration of heavy metal ions in the soil is relatively high, causing a more drastic environmental change, the structural change of the hydrogel will be more obvious, and more remediation agent will be released to meet the remediation requirements for high-concentration pollutants.

[0019] Relatively high environmental friendliness: Some conventional remediation agents are prone to introducing new pollutants during the remediation process or causing greater damage to the soil ecosystem. The intelligent complexing controlled-release remediation material adopts a relatively mild remediation method, and most of the materials used have good biocompatibility. For example, chitosan, as a natural polymer, is itself environmentally friendly and does not produce a large amount of secondary pollutants during the remediation process, has a relatively small impact on the soil microbial community, and is conducive to maintaining the stability of the soil ecosystem.

[0020] Second, the expected benefits after the transformation of the technical solution of the present invention include direct sales benefits and long-term cooperation benefits. Among them, the direct sales benefits refer to directly selling the intelligent complex-controlled release soil remediation material as a commodity to enterprises or institutions in need of soil remediation to obtain sales revenue, or providing customized intelligent responsive remediation materials and solutions according to the specific needs of different customers and charging higher service fees. The long-term cooperation benefits refer to signing long-term maintenance contracts with customers, regularly providing them with remediation materials and related services to ensure the long-term stability of the remediation effect and obtaining a continuous income stream; with the development of technology, continuously upgrading and optimizing the intelligent responsive remediation materials, and selling the upgraded products or services to old customers to increase the lifetime value of customers.

[0021] The commercial value of the present invention is mainly reflected in three aspects: the improvement of market competitiveness, industry promotion and cooperation opportunities, and environmental and social benefits.

[0022] I. In terms of the improvement of market competitiveness

[0023] Relying on its unique intelligent recognition and remediation functions, the intelligent complex-controlled release soil remediation material has higher remediation efficiency and effect compared with traditional remediation materials, can stand out in the market competition, attract more customers, and increase the market share. The successful promotion of this technical solution helps the enterprise to establish an innovative, environmentally friendly and efficient brand image, enhance the popularity and reputation of the brand, and lay a good foundation for the promotion of other products or services of the enterprise.

[0024] II. Industry promotion and cooperation opportunities

[0025] As a pioneer in intelligent responsive remediation materials, the enterprise can lead the development direction of the entire remediation material industry through technological innovation, promote the improvement of the industry's technical level, and formulate industry standards, so as to occupy a dominant position in the industry. The application of this technical solution may involve multiple fields and industries, bringing opportunities for the enterprise to establish cooperative relationships or strategic alliances with other enterprises, scientific research institutions, universities, etc., jointly carrying out activities such as R & D and promotion and application, realizing resource sharing and complementary advantages, and expanding business areas and market space.

[0026] III. Environmental and social benefits

[0027] The intelligent complex-controlled release remediation material can effectively repair the polluted soil environment, reduce the harm of heavy metals and other pollutants to the environment and human health, and reduce the impact of industrial production on the environment, which conforms to the global environmental protection trend and wins a good social reputation for the enterprise. Through the remediation of soil resources, the sustainable utilization of land resources is realized, which has important social value.

[0028] The material of the present invention uses mercaptochitosan as the recognition element, which can accurately recognize specific heavy metal ions. At the same time, ethylenediaminetetraacetic acid disodium is combined as a repair agent to achieve efficient chelation and fixation of heavy metal ions. This intelligent response mechanism that tightly combines the recognition and repair functions is an innovation in the field of soil heavy metal pollution remediation. Compared with traditional repair materials, it can more specifically solve pollution problems, improve the repair efficiency and effect, and fill the gap in precise repair technology.

[0029] Mercaptochitosan is a modified product of a natural polymer material, with good biocompatibility and degradability. Although ethylenediaminetetraacetic acid disodium is a synthetic compound, when used in combination with chitosan in this technical solution, it can achieve stable chelation of heavy metals, reducing secondary pollution to the environment during the repair process. This environmentally friendly repair material system fills the relevant technical gaps in the domestic and international industry's demand for green and environmental protection repair technologies, providing new ideas and methods for sustainable soil remediation.

[0030] The intelligent complexing and controlled-release repair material can automatically trigger the repair reaction according to the presence and concentration changes of heavy metal ions in the soil. This intelligent response characteristic makes the repair process more intelligent and automated, without the need for frequent manual intervention and complex monitoring equipment. Currently, in the field of soil remediation, the research and application of intelligent response materials are relatively few. The technical solution of this invention is innovative in this regard, filling the technical gap of the intelligent repair mechanism in the field of soil remediation and providing a new direction for the development of future soil remediation technologies.

[0031] Third, the technical solution of the present invention overcomes technical biases:

[0032] 1) Previous repair materials may pursue broad applicability but lack precision in targeting specific heavy metal repairs. The technical solution of this invention uses mercaptochitosan to accurately recognize specific heavy metal ions, overcoming the bias that repair materials need to be general but are difficult to act precisely, demonstrating the ability to precisely repair specific heavy metal pollution.

[0033] 2) It is generally believed that although environmentally friendly materials are environmentally friendly, their repair efficiency may be lower than that of traditional chemically synthesized materials. However, in this technical solution, mercaptochitosan, as a modified product of a natural polymer material, is combined with ethylenediaminetetraacetic acid disodium to achieve efficient repair, changing the view that environmentally friendly materials have low repair efficiency.

[0034] 3) Intelligent repair materials may previously have had problems such as unstable response mechanisms and easy failure during long-term use, leading to doubts about their durability. This technical solution enables the material to stably trigger the repair reaction through the synergistic effect of mercaptochitosan and ethylenediaminetetraacetic acid disodium, with high reliability and repeatability, overcoming the bias against the poor durability of intelligent repair materials.

[0035] 4) It is generally believed that the compounding of different functional materials may have compatibility problems, affecting the overall performance. However, the present invention effectively combines the recognition function of mercaptochitosan with the repair function of disodium ethylenediaminetetraacetate, achieving the synergistic effect of the two and breaking the prejudice that it is difficult to achieve ideal results in the compounding of materials. Description of the Drawings

[0036] Figure 1 It is a structural diagram of the intelligent complexing controlled-release soil remediation material provided by an embodiment of the present invention;

[0037] Figure 2 It is an external view of the medicament provided by an embodiment of the present invention;

[0038] Figure 3 It is a diagram of the experimental situation of contaminated soil provided by an embodiment of the present invention. Detailed Description of the Invention

[0039] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0040] As Figure 1 , an embodiment of the present invention provides an intelligent complexing controlled-release soil remediation material, which mainly consists of three parts: a responsive matrix, a recognition element, and a remediation agent.

[0041] Responsive matrix: Poly(N-isopropylacrylamide) hydrogel is selected, which has thermosensitivity and certain swelling properties. At room temperature, its network structure is relatively compact and can effectively load other components; when the external environment changes, such as the minute temperature or pH value changes caused by the change of pollutant concentration, it can respond quickly and swell or shrink.

[0042] Recognition element: Mercaptochitosan is used as the recognition element. Chitosan is a natural polymer with good biocompatibility and the ability to chelate metal ions. After mercapto modification, its selectivity and affinity for heavy metal ions are stronger.

[0043] Remediation agent: Disodium ethylenediaminetetraacetate (EDTA-2Na) is loaded as the remediation agent.

[0044] For the preparation of the responsive matrix, 10 g of N-isopropylacrylamide monomer, 0.05 g of N,N'-methylenebisacrylamide (crosslinking agent), and 0.03 g of ammonium persulfate (initiator) are added to 100 mL of deionized water. Under nitrogen protection, the mixture is stirred and reacted at 60 °C for 4 - 6 hours to form a poly(N-isopropylacrylamide) hydrogel matrix.

[0045] For the preparation of the recognition element, 5 g of chitosan was dissolved in 100 mL of 1% acetic acid solution, and 3 - 5 g of mercapto reagent (3-mercaptopropionic acid) was added. The mixture was stirred and reacted at 40 - 50 °C for 6 - 8 hours to obtain mercaptochitosan. Then it was uniformly mixed into the prepared poly(N-isopropylacrylamide) hydrogel matrix.

[0046] For the preparation of the repair agent, the prepared hydrogel matrix containing the recognition element was immersed in a 0.5 mol / L EDTA-2Na solution for 12 - 24 hours to allow EDTA-2Na to fully diffuse into the hydrogel network structure, completing the loading of the repair agent. Finally, an intelligent complex-controlled release repair material was obtained. When encountering heavy metal ions in the soil, mercaptochitosan recognized and bound to the heavy metal ions, triggering a structural change in the hydrogel matrix and releasing EDTA-2Na, which underwent a chelation reaction with the heavy metal ions to achieve the purpose of soil repair.

[0047] Dissolve or disperse the components of the repair material in a deionized water solvent in a certain proportion, and add an appropriate amount of dispersant and auxiliary agent to form a uniform liquid repair material.

[0048] Regarding the intelligent complex-controlled release soil repair material provided in the embodiments of the present invention, from the perspective of the degree of heavy metal pollution, for slightly polluted soil (heavy metal content close to or slightly higher than the soil environmental quality standard), the material addition amount is generally 0.5% - 1% of the soil quality. For moderately polluted soil (heavy metal content exceeding the standard by 1 - 3 times), the addition ratio can be increased to 1% - 3%. For severely polluted soil (heavy metal content exceeding the standard by more than 3 times), the addition ratio is usually 3% - 5%.

[0049] The intelligent repair function of the intelligent complex-controlled release repair material provided in the embodiments of the present invention mainly depends on its unique composition structure and the synergistic effect between its components.

[0050] Specific recognition of the recognition element: Mercaptochitosan, as the recognition element, has a unique chemical structure. The mercapto groups (-SH) on its molecular chain have extremely strong affinity for heavy metal ions, responsible for precisely identifying specific heavy metal ions such as lead, cadmium, mercury, and copper in a complex soil environment. Using its specific affinity for heavy metal ions, it takes the lead in binding to heavy metal ions, acting as a "detector" and "capturer", providing a targeted target for subsequent repair reactions. This specific recognition is based on the complexation reaction between mercapto groups and heavy metal ions. When heavy metal ions in the soil approach mercaptochitosan, the mercapto groups will quickly bind to the heavy metal ions to form a stable complex. For example, for lead ions (Pb 2 +), multiple mercapto groups on mercaptochitosan will bind to Pb 2A coordination reaction occurs to form a stable five - or six - membered ring structure, thus achieving efficient capture of lead ions.

[0051] Signal transduction and structural changes in the responsive matrix: Poly(N - isopropylacrylamide) hydrogel, as the responsive matrix, not only provides a carrier platform for the recognition element and the repair agent but also plays a crucial role in signal transduction and structural regulation during the intelligent repair process. When the recognition element captures heavy metal ions, it triggers changes in the local microenvironment, such as slight temperature and pH changes. Poly(N - isopropylacrylamide) hydrogel is extremely sensitive to these environmental changes and will rapidly undergo structural changes such as swelling or shrinking. For example, when the temperature rises or the pH changes, the molecular chains of the hydrogel will stretch or curl, and this structural change is like a "switch" that can trigger the release mechanism of the repair agent.

[0052] Release of the repair agent and the repair reaction: Disodium ethylenediaminetetraacetate (EDTA - 2Na), which is loaded in the hydrogel network structure as the repair agent, starts to be released from the pores of the hydrogel under the trigger of the structural change of the responsive matrix. Once released, EDTA - 2Na will rapidly undergo a chelation reaction with the heavy metal ions captured by the recognition element. EDTA - 2Na has multiple coordination atoms and can form stable chelates with heavy metal ions, desorbing the heavy metal ions from the soil particle surface and fixing them in the chelates, thereby reducing the mobility and bioavailability of heavy metal ions in the soil and achieving the purpose of soil remediation. The repair agent plays a major repair role after the recognition element captures heavy metal ions and triggers a series of reactions, and is the key executor for realizing soil remediation. The recognition element and the repair agent cooperate with each other to jointly complete the intelligent repair process of heavy metal pollutants in the soil.

[0053] In summary, through a series of synergistic effects including the specific recognition of the recognition element, the signal transduction and structural changes of the responsive matrix, and the release and repair reaction of the repair agent, the intelligent complexing controlled - release repair material realizes the intelligent and efficient repair of heavy metal pollutants in the soil.

[0054] In deep - soil remediation projects, through the drilling and injection system, the liquid repair material can be smoothly injected into the deep soil and naturally diffuse in the soil, achieving mixing with the soil without additional strong stirring. The concentration of the liquid repair material can be adjusted according to the pollution situation in different areas to achieve precise remediation.

[0055] Using an engineering drill rig, drill holes at a certain spacing in the polluted area, and the drilling depth should reach the bottom of the polluted soil. During the drilling process, pay attention to maintaining the verticality and stability of the drill holes to avoid problems such as hole collapse. After the drilling is completed, install a specially made repair material injection pipe in each drill hole. The bottom of the injection pipe should extend to the bottom of the polluted soil. Inject the pre-prepared repair material into the injection pipe in the drill hole through the injection equipment at a certain speed and pressure. To ensure that the repair material can be evenly distributed in the deep soil, a segmented injection method can be adopted. After injecting a certain amount of material, pause for a period of time (usually 1-2 hours) to allow the material to naturally diffuse in the soil, and then carry out the next injection. During the injection process, monitor parameters such as injection pressure and flow rate in real time to ensure the smooth progress of the injection process.

[0056] The intelligent complexing controlled-release soil repair material provided by the embodiment of the present invention has the following treatment efficiencies for different heavy metals:

[0057] The appearance of the medicament is as Figure 2

[0058] The experimental situation of the polluted soil is as Figure 3 ;

[0059] Experimental data on the removal effect of polluted soil

[0060]

[0061] Example 1: Remediation of slightly polluted soil

[0062] (1) Preparation of the response matrix: Weigh 10 g of N-isopropylacrylamide (NIPAM) monomer, 0.05 g of cross-linking agent N,N'-methylenebisacrylamide, and 0.03 g of ammonium persulfate initiator. Add them to 100 mL of deionized water. Under nitrogen protection, stir and react at 60 °C for 4 hours to form a uniform and transparent poly-N-isopropylacrylamide hydrogel matrix.

[0063] (2) Preparation of the recognition element: Dissolve 5 g of chitosan completely in 100 mL of 1% acetic acid aqueous solution. Add 3 g of mercapto-functionalized reagent (3-mercaptopropionic acid), and stir and react at 50 °C for 6 hours to obtain mercapto-functionalized chitosan; uniformly mix the mercapto-functionalized chitosan into the above hydrogel matrix and stir until completely fused to form a hydrogel composite matrix with the ability to recognize heavy metal ions.

[0064] (3) Loading of the repair agent: Immerse the above hydrogel composite matrix in a 0.5 mol / L EDTA-2Na solution and soak it at room temperature for 12 hours to ensure that EDTA-2Na fully diffuses into the gel structure to complete the preparation of the loading of the repair agent, and finally obtain the intelligent complexing controlled-release soil repair material.

[0065] (4) Soil remediation application: The above materials were evenly added to slightly contaminated soil at a ratio of 0.8% of the soil quality. Regular monitoring found that the concentration of heavy metal ions in the soil decreased significantly. After 4 weeks of application, the content of heavy metal ions in the soil decreased by more than about 70%, and the soil remediation effect was good.

[0066] Example 2: Remediation of severely contaminated soil

[0067] (1) Preparation of the responsive matrix: Take 10 g of N-isopropylacrylamide monomer, 0.05 g of cross-linking agent N,N'-methylenebisacrylamide, and 0.03 g of ammonium persulfate, mix and add them to 100 mL of deionized water, and react at 60 °C for 6 hours under nitrogen protection to obtain a transparent and stable poly-N-isopropylacrylamide hydrogel matrix.

[0068] (2) Preparation of the recognition element: Dissolve 5 g of chitosan in 100 mL of 1% acetic acid solution, then add 5 g of mercapto-functionalized reagent (3-mercaptopropionic acid), and react at a constant temperature of 40 °C for 8 hours to obtain mercapto-functionalized chitosan; mix it thoroughly into the poly-N-isopropylacrylamide hydrogel matrix to prepare a composite matrix that can specifically recognize and capture heavy metal ions.

[0069] (3) Loading of the repair agent: Place the above composite hydrogel matrix in a 0.5 mol / L EDTA-2Na solution and soak it at room temperature for 24 hours to allow EDTA-2Na to fully penetrate and be loaded into the gel matrix network, and finally obtain a high-loading intelligent controlled-release soil repair material.

[0070] (4) Soil remediation application: Incorporate the material prepared above into severely contaminated soil at a ratio of 5%. After detection and analysis, the material quickly responds and releases EDTA-2Na after contacting the soil, and efficiently chelates heavy metal ions in the soil. After 8 weeks of application, the concentration of heavy metal ions decreased by more than 85%, achieving an ideal soil remediation effect.

[0071] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, any modifications, equivalent substitutions, and improvements made within the spirit and principle of the present invention should be covered by the protection scope of the present invention.

Claims

1. An intelligent complexing controlled-release soil remediation material, characterized in that, The intelligent complex-controlled release soil remediation material mainly consists of three parts: a responsive matrix, an identification element, and a remediation agent; the responsive matrix is selected as poly(N-isopropylacrylamide) hydrogel; the identification element is thiolated chitosan; and the remediation agent is loaded with disodium ethylenediaminetetraacetate (EDTA-2Na).

2. The intelligent complexing controlled-release soil remediation material according to claim 1, wherein For the preparation of the responsive matrix, 10 g of N-isopropylacrylamide monomer, 0.05 g of N,N'-methylenebisacrylamide (crosslinking agent), and 0.03 g of ammonium persulfate (initiator) are added to 100 mL of deionized water. Under nitrogen protection, the mixture is stirred at 60 °C for 4 - 6 hours to form a poly(N-isopropylacrylamide) hydrogel matrix.

3. The intelligent complex-controlled release soil remediation material according to claim 1, characterized in that, For the preparation of the identification element, 5 g of chitosan is dissolved in 100 mL of 1% acetic acid solution, and 3 - 5 g of thiolation reagent (3-mercaptopropionic acid) is added. The mixture is stirred at 40 - 50 °C for 6 - 8 hours to obtain thiolated chitosan, and then it is uniformly mixed into the poly(N-isopropylacrylamide) hydrogel matrix prepared above.

4. The intelligent complex-controlled release soil remediation material according to claim 1, wherein For the preparation of the remediation agent, the prepared hydrogel matrix containing the identification element is immersed in a 0.5 mol / L EDTA-2Na solution for 12 - 24 hours to allow EDTA-2Na to fully diffuse into the hydrogel network structure, completing the loading of the remediation agent. Finally, an intelligent complex-controlled release remediation material is obtained. When encountering heavy metal ions in the soil, thiolated chitosan identifies and binds to the heavy metal ions, triggering a structural change in the hydrogel matrix and releasing EDTA-2Na, which undergoes a chelation reaction with the heavy metal ions to achieve the purpose of soil remediation.

5. The intelligent complex-controlled release soil remediation material according to claim 1, characterized in that, For the intelligent complex-controlled release soil remediation material, for slightly contaminated soil, the material addition amount is generally 0.5% - 1% of the soil mass; for moderately contaminated soil, the addition ratio can be increased to 1% - 3%; for severely contaminated soil, the addition ratio is usually 3% - 5%.

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