Soil heavy metal remediation method based on driving of degradable nanocomposite

Abstract

The invention provides a soil heavy metal remediation method based on driving of a degradable nano composite material, and relates to the technical field of safety monitoring and fault diagnosis of a power system. Comprising a data acquisition subsystem, a data processing subsystem, a fire risk assessment subsystem, a multi-dimensional analysis subsystem, an early warning module, a multi-source data fusion module, an after-event analysis subsystem and a self-learning mechanism module. Abnormal conditions in line operation can be found in time, fire hazards caused by delayed detection are effectively avoided, the efficiency and timeliness of line monitoring are improved, monitored electrical data are analyzed and processed by adopting a machine learning algorithm, abnormal modes can be automatically recognized, potential causes of fire occurrence can be judged, and the method is suitable for popularization and application. The system not only depends on single threshold alarm, but also provides more accurate fire early warning through deep analysis of historical data and operation trend.

Description

Technical Field

[0001] The present invention relates to the technical field of safety monitoring and fault diagnosis of power systems, and in particular to a soil heavy metal remediation method driven by degradable nanocomposite materials. Background Art

[0002] With the development of modern power systems, transmission lines, as an important part of power transmission, have a direct impact on the safety and stability of the entire power grid. Transmission line fires not only cause economic losses, but may also lead to large-scale power outages and affect the normal operation of society. Therefore, how to accurately and timely identify the causes of transmission line fires and reduce fire risks has become a key research direction in the field of power systems.

[0003] At present, the monitoring and identification of the causes of transmission line fires mainly rely on the following technical means:

[0004] Manual inspection: Traditional fire prevention measures include regular manual inspections of transmission lines, using personnel and detection equipment to detect potential risks. Although manual inspections can ensure line safety to a certain extent, this method has problems such as high cost, low efficiency, and poor real-time performance, making it difficult to provide timely warnings and identification of fires.

[0005] Infrared thermal imaging technology: Infrared thermal imaging technology can detect overheated wires, insulators or other equipment by detecting temperature changes in transmission lines. This technology has the advantages of non-contact and strong real-time performance, and can assist in detecting fire precursors. However, it is greatly affected by environmental factors (such as weather, sunshine, etc.), and the cost is high, so it is not suitable for large-scale transmission line monitoring.

[0006] Drone monitoring: With the advancement of drone technology, the use of drones for aerial monitoring of power transmission lines has become an effective means. Drones are equipped with sensors such as infrared imaging and high-definition cameras, which can quickly obtain the operating status of power transmission lines. However, drone monitoring also has problems such as short flight time and difficulty in all-weather monitoring.

[0007] Electrical parameter monitoring: Abnormalities in electrical parameters such as current, voltage, and power can often indicate potential problems in the transmission line. For example, abnormal increase in current may be caused by line short circuit, equipment aging, or other problems, which in turn may cause a fire. By monitoring the electrical characteristic parameters of the transmission line, the health status of the line can be more accurately reflected and provide a basis for early warning of fires.

[0008] Although existing monitoring and identification technologies have played an important role in preventing transmission line fires, they still have many shortcomings:

[0009] Problem 1: Traditional manual inspections are time-consuming, have limited coverage, and cannot achieve real-time monitoring of transmission lines. This makes it difficult to detect potential fire hazards in a timely manner and effectively prevent fires.

[0010] Problem 2: Although the use of advanced equipment such as infrared thermal imaging and drones for monitoring can achieve relatively accurate fire warnings, the equipment is expensive and has high maintenance costs, making it difficult to promote and apply on a large scale, especially on long-distance transmission lines. In addition, infrared imaging is greatly affected by weather and the environment, and its reliability will be reduced under harsh conditions;

[0011] Problem 3: Most of the existing monitoring methods rely on regular inspections or periodic drone patrols, lacking real-time and continuous monitoring capabilities. This non-real-time nature will result in hidden dangers not being discovered in time in the early stages of a fire, thus missing the best time for prevention and control;

[0012] Question 4: Although monitoring electrical characteristic parameters can predict the occurrence of line faults and fires, traditional technologies mainly rely on simple threshold alarms and fail to fully utilize modern data analysis methods (such as machine learning and data mining technology) to conduct in-depth analysis of electrical parameters. Simply relying on set thresholds can easily lead to false alarms and missed alarms, and cannot provide accurate risk assessments.

[0013] Therefore, a soil heavy metal remediation method based on degradable nanocomposites is needed to solve the above problems. Summary of the invention

[0014] Technical issues solved

[0015] In view of the shortcomings of the prior art, the present invention provides a soil heavy metal remediation method based on degradable nanocomposite materials, which solves the following problems:

[0016] 1. It solves the problem that traditional manual inspection is time-consuming, has limited coverage, and cannot achieve real-time monitoring of transmission lines. This makes it difficult to discover potential fire hazards in time and cannot effectively prevent fires.

[0017] 2. It solves the problem that the use of advanced equipment such as infrared thermal imaging and drones for monitoring can achieve relatively accurate fire warnings, but the equipment is expensive and has high maintenance costs, especially on long-distance transmission lines. In addition, infrared imaging is greatly affected by weather and environment, and its reliability will be reduced under harsh conditions.

[0018] 3. It solves the problem that most of the existing monitoring methods rely on regular inspections or periodic drone patrols, lacking real-time and continuous monitoring capabilities. This non-real-time nature will lead to hidden dangers not being discovered in time in the early stages of a fire, thus missing the best time for prevention and control;

[0019] 4. Solve the problem that although the existing technology can predict the occurrence of line faults and fires by monitoring electrical characteristic parameters, the traditional technology mainly relies on simple threshold alarms and fails to make full use of modern data analysis methods to conduct in-depth analysis of electrical parameters. Simply relying on set thresholds can easily lead to false alarms and missed alarms, and cannot provide accurate risk assessment.

[0020] Technical Solution

[0021] To achieve the above objectives, the present invention is implemented by the following technical scheme: a soil heavy metal remediation method driven by degradable nanocomposite materials, comprising the following steps:

[0022] S1. Before carrying out soil heavy metal remediation work, a soil remediation system is constructed, and the remediation method is implemented by relying on the soil remediation system for operation, management and regulation;

[0023] The soil remediation system includes a soil sampling and analysis subsystem, a nanomaterial preparation subsystem, a remediation plan customization subsystem, a contaminated area positioning subsystem, a remediation process monitoring subsystem, a microbial enhancement subsystem, a moisture control subsystem, a vegetation restoration guidance subsystem, an environmental risk assessment subsystem, and a remediation effect assessment subsystem. When the soil remediation system is started, the soil sampling and analysis subsystem collects and detects soil sample information; when in operation, the nanomaterial preparation subsystem prepares an adapted degradable nanocomposite material; the remediation plan customization subsystem plans the remediation process according to the soil contamination status and site conditions; the contaminated area positioning subsystem uses a geographic information system to accurately locate the contaminated area;

[0024] The nanomaterial preparation subsystem adopts three processes of physical blending, in-situ polymerization and sol-gel, combines biodegradable polymer matrix and nano-functional materials, and prepares a degradable nano-composite material with strong adsorption and fixation ability for heavy metals. The biodegradable polymer matrix is ​​selected from polylactic acid, polyhydroxyalkanoate, chitosan, and the nano-functional materials are selected from nano-zero-valent iron, nano-titanium dioxide, and nano-montmorillonite. During the preparation process, the material formula is accurately optimized according to the target heavy metal type, content and soil characteristics;

[0025] The microbial enhancement subsystem introduces microbial flora, promotes the degradation of degradable nanocomposites and the transformation of heavy metals with the help of microbial metabolic activities, and accelerates the repair process by using organic acids and enzymes produced by microorganisms; the moisture regulation subsystem reasonably arranges irrigation and drainage according to soil moisture content, climatic conditions and repair stage requirements, maintains suitable soil humidity, and ensures the effect of the degradable nanocomposites and heavy metals; when the soil remediation system is started, the soil sampling and analysis subsystem collects and detects soil sample information; the soil heavy metal remediation method based on degradable nanocomposites driven comprises the following steps:

[0026] S2. After the restoration work is started, the soil sampling and analysis subsystem is linked with the soil detector to collect soil samples at three different depths of 0-20 cm, 20-40 cm and 40-60 cm in the area to be restored. Atomic absorption spectroscopy, inductively coupled plasma mass spectrometry are used to determine the content, morphological distribution and basic physical and chemical properties of soil heavy metals. At the same time, a soil information database is constructed for subsequent query and comparison;

[0027] S3, updating soil sample data every month, and resampling and analyzing in time within seven days when the soil properties change significantly, including external interference factors such as heavy rainfall and new pollution sources in the surrounding area; preparing the adapted degradable nanocomposite material through the nanomaterial preparation subsystem during operation, the specific steps are:

[0028] S4. Based on the results of the previous soil sampling and analysis, the nanomaterial preparation subsystem selects appropriate biodegradable polymer matrices and nano-functional materials. When the soil is seriously polluted by lead and cadmium, polyhydroxyalkanoate matrices combined with nano-zero-valent iron functional materials are preferred; when mercury pollution is prominent, chitosan matrices combined with nano-titanium dioxide functional materials are considered;

[0029] S5. Prepare degradable nanocomposites by uniformly dispersing nanofunctional materials in polymer matrices through physical blending, in-situ polymerization, and sol-gel methods, and use scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy for quality inspection and performance optimization;

[0030] The remediation solution customization subsystem plans the remediation process according to the soil pollution status and site conditions. The specific steps are as follows:

[0031] S6. Comprehensive soil sampling and analysis data, site hydrogeological information and pollution source investigation results, the remediation plan customization subsystem formulates a detailed remediation plan, clearly stating that the amount of degradable nanocomposites to be added is 0.5%-5% of the soil mass, the placement method is to spread the application and then till the soil for uniform mixing, and the remediation period is set at 6-24 months according to the degree of pollution;

[0032] S7. Combine the actual construction conditions and potential risk factors, use numerical simulation software to simulate and predict the implementation effects of different restoration schemes in complex soil environments, compare and analyze the advantages and disadvantages of each scheme, select the best scheme and make fine adjustments according to the actual situation to ensure the feasibility and effectiveness of the scheme;

[0033] The polluted area positioning subsystem uses the geographic information system to accurately locate the polluted area, and its execution steps are as follows:

[0034] S8. Collect the topography, land use status and historical satellite image data of the site to be restored and import them into the geographic information system;

[0035] S9. Using the spatial analysis function of the geographic information system, combined with the heavy metal exceeding standard area information in the soil sampling analysis data, the pollution range is accurately delineated to provide coordinate guidance for targeted remediation. The microbial enhancement subsystem introduces specific microbial flora to promote the degradation of degradable nanocomposites and the transformation of heavy metals with the help of microbial metabolic activities. The specific steps are as follows:

[0036] S10. According to soil characteristics and restoration goals, select microbial flora from the genera Bacillus, Pseudomonas and Rhodococcus that have the ability to decompose degradable materials and have tolerance and conversion capabilities to heavy metals. At the appropriate stage of the restoration process, inoculate the microbial flora into the soil at a prescribed dose of 100,000-10,000,000 colony-forming units per gram of soil. By monitoring the growth and reproduction of microorganisms and their impact on the restoration effect, adjust the microbial inoculation strategy every two months;

[0037] The water regulation subsystem arranges irrigation and drainage according to soil moisture content, climate conditions and restoration stage requirements to maintain suitable soil humidity and ensure the effect of the degradable nanocomposite material and heavy metals, and includes the following steps:

[0038] When the soil moisture content deviates from the appropriate range, the startup subsystem calculates the irrigation water volume and drainage time based on the preset drainage model and real-time meteorological data, accurately executes the control instructions through intelligent irrigation and drainage facilities, and monitors the soil moisture feedback in real time to ensure that the humidity is stable within a reasonable range to promote restoration.

[0039] Preferably, the repair process monitoring subsystem tracks the indicators in the repair process in real time, specifically:

[0040] Atomic absorption spectroscopy, inductively coupled plasma mass spectrometry and plasma mass spectrometry are used to monitor the changes in the total amount and effective content of heavy metals in the soil every month, which can directly reflect the effect of heavy metal removal and accurately determine whether the restoration process is in line with expectations;

[0041] The degradation rate of the degradable nanocomposites was tested every three months using thermogravimetric analysis and differential scanning calorimetry combined with weight loss measurement;

[0042] The soil pH value is measured by the potentiometric method, the soil organic matter content is measured by the potassium dichromate oxidation method, and the cation exchange capacity is measured by the ammonium acetate exchange method. The physical and chemical properties of the soil are monitored monthly to detect subtle changes in the soil environment in a timely manner, providing a basis for adjusting the restoration strategy;

[0043] With the help of high-throughput sequencing technology, the soil microbial community structure and diversity are analyzed every six months, and the impact of restoration measures on the soil ecosystem is evaluated from the microbial ecology level to ensure the healthy and stable development of soil microbial ecology.

[0044] Preferably, the vegetation restoration guidance subsystem promotes vegetation growth in the later stage of restoration and consolidates the restoration results. The operation details are as follows:

[0045] Based on the local climate, soil type and degree of pollution remediation, local native plant species are prioritized for vegetation restoration. Herbaceous plants include bermudagrass, clover and ryegrass, shrubs include Amorpha fruticosa, Hippophae rhamnoides and Lespedeza bicolor, and trees include poplar, willow and Sophora japonica. These plants have strong adaptability to the local environment and help to quickly rebuild the soil ecology.

[0046] In the early stage of vegetation planting, a detailed irrigation plan is formulated according to the growth characteristics of plants. The soil moisture content of herbaceous plants is maintained at 60%-70%, shrubs at 50%-60%, and trees at 40%-50%, and the irrigation amount is dynamically adjusted according to the growth stage of the plants;

[0047] In case of insufficient soil fertility, apply 5-10 kg of organic fertilizer, 0.1-0.3 kg of nitrogen fertilizer, 0.05-0.15 kg of phosphorus fertilizer, and 0.1-0.2 kg of potassium fertilizer per square meter to meet the nutrient needs of plants at different growth stages and promote the healthy growth of vegetation.

[0048] Preferably, the environmental risk assessment subsystem pre-assesses the environmental risks generated during the entire restoration process, including the following key points:

[0049] For the degradable nano-composite materials themselves, acute toxicity tests, chronic toxicity tests and bioaccumulation tests are used to evaluate their potential hazards to soil organisms and surrounding ecosystems, among which the soil organisms are earthworms and nematodes, to ensure the safety of the materials before and during degradation.

[0050] Consider the water regulation process during the restoration process, simulate extreme climatic conditions, assess the risk of material loss caused by poor drainage and the possibility of groundwater pollution caused by excessive irrigation, and ensure the rational use and protection of water resources throughout the restoration process.

[0051] Preferably, the soil sampling and analysis subsystem comprehensively collects basic soil information at the initial stage of restoration, and the operating specifications include:

[0052] Taking the center of the plot as the reference point, the sampling grid is divided by chessboard or snake sampling method. For plots with an area of ​​less than 1 hectare, the grid size is set to 10 meters × 10 meters; for plots with an area between 1-5 hectares, it is set to 20 meters × 20 meters; when it is larger than 5 hectares, it is set to 30 meters × 30 meters to ensure that the sampling points are evenly distributed and accurately reflect the overall soil pollution status. At each sampling point, the soil is collected in layers strictly according to the three standard depths of 0-20 cm, 20-40 cm and 40-60 cm. The soil layers at the same depth are fully mixed and taken as a sample to avoid sampling errors and provide reliable data support for the formulation of subsequent remediation plans.

[0053] Preferably, in the nanomaterial preparation subsystem, the key process parameters of the physical blending method, in-situ polymerization and sol-gel method are precisely controlled as follows:

[0054] Physical blending method: The stirring speed is controlled at 500-1000 rpm, the stirring time is 30-60 minutes, and the temperature is controlled at 40-60°C according to the material properties;

[0055] In-situ polymerization method: the initiator concentration is precisely adjusted to 0.5%-2%, the monomer concentration is 20%-40%, the reaction temperature is maintained at 60-80°C, and the reaction time is 4-8 hours;

[0056] Sol-gel method: The ratio of the precursor hydrolysis rate to the polycondensation reaction rate is controlled at 1:2-1:3, the hydrolysis degree is maintained at 30%-50%, the polycondensation degree is 40%-60%, and the pH value of the reaction system is strictly controlled between 3-5.

[0057] Preferably, the quantitative relationship between the microbial growth and reproduction dynamics and heavy metal transformation in the microbial enhancement subsystem is clearly defined as follows:

[0058] Microbial growth and reproduction follow the Monod equation:

[0059]

[0060] Where μ is the rate of change of microbial population over time (individuals / mL·s), μ max is the maximum growth rate (cells / mL·s), S is the substrate concentration (g / L), K s is the saturation constant of microbial growth (g / L). This equation accurately describes the growth dynamics of microorganisms in the soil environment and provides a theoretical basis for the rational inoculation and regulation of microorganisms. The transformation of heavy metals by microorganisms follows the first-order kinetic equation:

[0061] C t =C0e-kt

[0062] Among them C t is the heavy metal conversion amount at time t (mg / kg), C0 is the initial heavy metal content (mg / kg), k is the microbial conversion coefficient (s -1 ), by monitoring the changes in heavy metal content in different time periods, combined with the equation, the transformation efficiency of microorganisms to heavy metals is accurately evaluated to guide the optimization of the remediation process.

[0063] Preferably, the irrigation water volume and drainage time calculation model of the water regulation subsystem is precisely designed as follows:

[0064] Irrigation water volume is calculated based on the modified Penman-Monteith formula:

[0065]

[0066] η Where I is the irrigation water volume (m 3 ),ET0 is the reference crop evapotranspiration (mm / d), K c is the crop coefficient, A is the irrigation area (m 2 ),ρ w is the density of water (kg / m 3 ), Δθ is the change in soil moisture content in the planned wet layer, η is the irrigation water utilization coefficient, this formula takes into account a variety of factors and accurately calculates the amount of irrigation water that meets the soil moisture demand; the drainage time calculation is based on the improved model of Darcy's law:

[0067]

[0068] Where t is the drainage time (h), V is the amount of water to be discharged (m 3 ), K is soil permeability coefficient (m / s), A is drainage area (m 2 ), i is the hydraulic gradient. By real-time monitoring of soil moisture content and hydraulic conditions, the improved model of Darcy's law is used to accurately calculate the drainage time to prevent soil waterlogging.

[0069] Preferably, the steps of the restoration effect evaluation subsystem mainly include heavy metal removal effect evaluation, soil ecological function restoration evaluation, vegetation community stability consideration and surrounding environmental impact monitoring.

[0070] Beneficial Effects

[0071] The present invention provides a soil heavy metal remediation method based on degradable nanocomposite materials. It has the following beneficial effects:

[0072] 1. The present invention can timely detect abnormal conditions in line operation through real-time monitoring of electrical characteristic parameters such as current and voltage of the transmission line, effectively avoid fire hazards caused by delayed detection, and improve the efficiency and timeliness of line monitoring. It uses machine learning algorithms to analyze and process the monitored electrical data, and can automatically identify abnormal patterns and determine the potential causes of fire, reducing the probability of false alarms and missed alarms. The system not only relies on a single threshold alarm, but also provides more accurate fire warnings through in-depth analysis of historical data and operating trends.

[0073] 2. The present invention can automatically issue a fire risk alarm based on the analysis results, prompting relevant personnel to take preventive measures to reduce the probability of fire. In addition, the system can provide corresponding early warning strategies for different risk levels to achieve more flexible and reliable fire prevention.

[0074] 3. Compared with traditional manual inspections or high-cost equipment monitoring, the present invention realizes fire warning through the monitoring of electrical characteristic parameters, which is lower in cost and can be widely promoted and applied. It is suitable for all-weather monitoring of long-distance transmission lines, does not rely on infrared or other environmentally sensitive equipment, and can operate normally under various weather conditions. It overcomes the shortcomings of the prior art that are limited by weather and environmental changes, and improves the reliability of the system. The system can monitor the electrical characteristic parameters of the transmission lines in real time to ensure that abnormal changes in current or voltage are discovered at any time to avoid fire risks. It introduces machine learning or data-driven algorithms to conduct in-depth analysis of electrical parameters and can automatically identify abnormal patterns to determine potential causes of fires. When a high fire risk is detected, the system can promptly issue an alarm to remind relevant personnel to take emergency measures to reduce the possibility of fire. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] Figure 1 It is the overall framework diagram of the present invention;

[0076] Figure 2 It is a diagram of the method concept of the present invention. DETAILED DESCRIPTION

[0077] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Specific embodiment one:

[0079] like Figure 1-2 As shown, the soil heavy metal remediation method based on degradable nanocomposite materials includes the following steps:

[0080] S1. Before carrying out soil heavy metal remediation work, a soil remediation system should be established, and the remediation method should be operated, managed and regulated by the soil remediation system during implementation;

[0081] The soil remediation system includes soil sampling and analysis subsystem, nanomaterial preparation subsystem, remediation plan customization subsystem, contaminated area positioning subsystem, remediation process monitoring subsystem, microbial enhancement subsystem, water regulation subsystem, vegetation restoration guidance subsystem, environmental risk assessment subsystem and remediation effect assessment subsystem. When the soil remediation system is started, the soil sampling and analysis subsystem collects and detects soil sample information; during operation, the nanomaterial preparation subsystem prepares suitable degradable nanocomposites; the remediation plan customization subsystem plans the remediation process according to the soil pollution status and site conditions; the contaminated area positioning subsystem uses the geographic information system to accurately locate the contaminated area;

[0082] The nanomaterial preparation subsystem adopts three processes, namely physical blending, in-situ polymerization and sol-gel, and combines biodegradable polymer matrix with nano-functional materials to prepare biodegradable nano-composite materials with strong adsorption and fixation capabilities for heavy metals. The biodegradable polymer matrix is ​​made of polylactic acid, polyhydroxyalkanoate, and chitosan, and the nano-functional materials are made of nano-zero-valent iron, nano-titanium dioxide, and nano-montmorillonite. During the preparation process, the material formula is accurately optimized according to the target heavy metal type, content, and soil characteristics.

[0083] The microbial enhancement subsystem introduces microbial flora, promotes the degradation of degradable nanocomposites and the transformation of heavy metals with the help of microbial metabolic activities, and accelerates the remediation process by using organic acids and enzymes produced by microorganisms; the water regulation subsystem reasonably arranges irrigation and drainage according to soil moisture content, climatic conditions and remediation stage requirements, maintains suitable soil humidity, and ensures the effect of the degradable nanocomposites and heavy metals. When the soil remediation system is started, the soil sampling and analysis subsystem collects and detects soil sample information. The soil heavy metal remediation method driven by degradable nanocomposites includes the following steps:

[0084] S2. After the restoration work is started, the soil sampling and analysis subsystem is linked with the soil detector to collect soil samples at three different depths of 0-20 cm, 20-40 cm and 40-60 cm in the area to be restored. Atomic absorption spectroscopy, inductively coupled plasma mass spectrometry are used to determine the content, morphological distribution and basic physical and chemical properties of soil heavy metals. At the same time, a soil information database is constructed for subsequent query and comparison;

[0085] S3. Update soil sample data every month. When soil properties change significantly, including external interference factors such as heavy rainfall and new pollution sources in the surrounding area, resample and analyze in time within seven days. Prepare the appropriate degradable nanocomposite materials through the nanomaterial preparation subsystem during operation. The specific steps are as follows:

[0086] S4. Based on the results of the previous soil sampling and analysis, the nanomaterial preparation subsystem selects appropriate biodegradable polymer matrices and nano-functional materials. When the soil is seriously polluted by lead and cadmium, polyhydroxyalkanoate matrices combined with nano-zero-valent iron functional materials are preferred; when mercury pollution is prominent, chitosan matrices combined with nano-titanium dioxide functional materials are considered;

[0087] S5. Prepare degradable nanocomposites by uniformly dispersing nanofunctional materials in polymer matrices through physical blending, in-situ polymerization, and sol-gel methods, and use scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy for quality inspection and performance optimization;

[0088] The remediation solution customization subsystem plans the remediation process based on the soil pollution status and site conditions. The specific steps are as follows:

[0089] S6. Comprehensive soil sampling and analysis data, site hydrogeological information and pollution source investigation results, the remediation plan customization subsystem formulates a detailed remediation plan, clearly stating that the amount of degradable nanocomposites to be added is 0.5%-5% of the soil mass, the placement method is to spread the application and then till the soil for uniform mixing, and the remediation period is set at 6-24 months according to the degree of pollution;

[0090] S7. Combine the actual construction conditions and potential risk factors, use numerical simulation software to simulate and predict the implementation effects of different restoration schemes in complex soil environments, compare and analyze the advantages and disadvantages of each scheme, select the best scheme and make fine adjustments according to the actual situation to ensure the feasibility and effectiveness of the scheme;

[0091] The pollution area positioning subsystem uses the geographic information system to accurately locate the pollution area. The execution steps are as follows:

[0092] S8. Collect the topography, land use status and historical satellite image data of the site to be restored and import them into the geographic information system;

[0093] S9. Using the spatial analysis function of the geographic information system, combined with the heavy metal exceeding standard area information in the soil sampling analysis data, the pollution range is accurately delineated to provide coordinate guidance for targeted remediation. The microbial enhancement subsystem introduces specific microbial flora to promote the degradation of degradable nanocomposites and the transformation of heavy metals with the help of microbial metabolic activities. The specific steps are as follows:

[0094] S10. According to soil characteristics and restoration goals, select microbial flora from the genera Bacillus, Pseudomonas and Rhodococcus that have the ability to decompose degradable materials and have tolerance and conversion capabilities to heavy metals. At the appropriate stage of the restoration process, inoculate the microbial flora into the soil at a prescribed dose of 100,000-10,000,000 colony-forming units per gram of soil. By monitoring the growth and reproduction of microorganisms and their impact on the restoration effect, adjust the microbial inoculation strategy every two months;

[0095] The water regulation subsystem arranges irrigation and drainage according to soil moisture content, climatic conditions and the needs of the restoration stage to maintain suitable soil moisture and ensure the effect of the degradable nanocomposites and heavy metals. It also includes the following steps:

[0096] When the soil moisture content deviates from the appropriate range, the startup subsystem calculates the irrigation water volume and drainage time based on the preset drainage model and real-time meteorological data, accurately executes the control instructions through intelligent irrigation and drainage facilities, and monitors the soil moisture feedback in real time to ensure that the humidity is stable within a reasonable range to promote restoration.

[0097] The repair process monitoring subsystem tracks the indicators of the repair process in real time, specifically:

[0098] Atomic absorption spectroscopy, inductively coupled plasma mass spectrometry and plasma mass spectrometry are used to monitor the changes in the total amount and effective content of heavy metals in the soil every month, which can directly reflect the effect of heavy metal removal and accurately determine whether the restoration process is in line with expectations;

[0099] The degradation rate of the degradable nanocomposites was tested every three months using thermogravimetric analysis and differential scanning calorimetry combined with weight loss measurement;

[0100] The soil pH value is measured by the potentiometric method, the soil organic matter content is measured by the potassium dichromate oxidation method, and the cation exchange capacity is measured by the ammonium acetate exchange method. The physical and chemical properties of the soil are monitored monthly to detect subtle changes in the soil environment in a timely manner, providing a basis for adjusting the restoration strategy;

[0101] With the help of high-throughput sequencing technology, the soil microbial community structure and diversity are analyzed every six months, and the impact of restoration measures on the soil ecosystem is evaluated from the microbial ecology level to ensure the healthy and stable development of soil microbial ecology.

[0102] The vegetation restoration guidance subsystem promotes vegetation growth in the later stage of restoration and consolidates the restoration results. The operation details are as follows:

[0103] Based on the local climate, soil type and degree of pollution remediation, local native plant species are prioritized for vegetation restoration. Herbaceous plants include bermudagrass, clover and ryegrass, shrubs include Amorpha fruticosa, Hippophae rhamnoides and Lespedeza bicolor, and trees include poplar, willow and Sophora japonica. These plants have strong adaptability to the local environment and help to quickly rebuild the soil ecology.

[0104] In the early stage of vegetation planting, a detailed irrigation plan is formulated according to the growth characteristics of plants. The soil moisture content of herbaceous plants is maintained at 60%-70%, shrubs at 50%-60%, and trees at 40%-50%, and the irrigation amount is dynamically adjusted according to the growth stage of the plants;

[0105] In case of insufficient soil fertility, apply 5-10 kg of organic fertilizer, 0.1-0.3 kg of nitrogen fertilizer, 0.05-0.15 kg of phosphorus fertilizer, and 0.1-0.2 kg of potassium fertilizer per square meter to meet the nutrient needs of plants at different growth stages and promote the healthy growth of vegetation.

[0106] The environmental risk assessment subsystem pre-evaluates the environmental risks generated by the entire restoration process, including the following key points:

[0107] For the degradable nano-composite materials themselves, acute toxicity tests, chronic toxicity tests and bioaccumulation tests are used to evaluate their potential hazards to soil organisms and surrounding ecosystems, among which the soil organisms are earthworms and nematodes, to ensure the safety of the materials before and during degradation.

[0108] Consider the water regulation process during the restoration process, simulate extreme climatic conditions, assess the risk of material loss caused by poor drainage and the possibility of groundwater pollution caused by excessive irrigation, and ensure the rational use and protection of water resources throughout the restoration process.

[0109] The soil sampling and analysis subsystem collects comprehensive soil basic information at the beginning of the restoration. The operating specifications include:

[0110] Taking the center of the plot as the reference point, the sampling grid is divided by chessboard or snake sampling method. For plots with an area of ​​less than 1 hectare, the grid size is set to 10 meters × 10 meters; for plots with an area between 1-5 hectares, it is set to 20 meters × 20 meters; when it is larger than 5 hectares, it is set to 30 meters × 30 meters to ensure that the sampling points are evenly distributed and accurately reflect the overall soil pollution status. At each sampling point, the soil is collected in layers strictly according to the three standard depths of 0-20 cm, 20-40 cm and 40-60 cm. The soil layers at the same depth are fully mixed and taken as a sample to avoid sampling errors and provide reliable data support for the formulation of subsequent remediation plans.

[0111] In the nanomaterial preparation subsystem, the key process parameters of physical blending, in-situ polymerization and sol-gel methods are precisely controlled as follows:

[0112] Physical blending method: The stirring speed is controlled at 500-1000 rpm, the stirring time is 30-60 minutes, and the temperature is controlled at 40-60°C according to the material properties;

[0113] In-situ polymerization method: the initiator concentration is precisely adjusted to 0.5%-2%, the monomer concentration is 20%-40%, the reaction temperature is maintained at 60-80°C, and the reaction time is 4-8 hours;

[0114] Sol-gel method: The ratio of the precursor hydrolysis rate to the polycondensation reaction rate is controlled at 1:2-1:3, the hydrolysis degree is maintained at 30%-50%, the polycondensation degree is 40%-60%, and the pH value of the reaction system is strictly controlled between 3-5.

[0115] The quantitative relationship between the growth and reproduction dynamics of microorganisms and the transformation of heavy metals in the microbial enhancement subsystem is as follows:

[0116] Microbial growth and reproduction follow the Monod equation:

[0117]

[0118] Where μ is the rate of change of microbial population over time (individuals / mL·s), μ max is the maximum growth rate (cells / mL·s), S is the substrate concentration (g / L), K s is the saturation constant of microbial growth (g / L). This equation accurately describes the growth dynamics of microorganisms in the soil environment and provides a theoretical basis for the rational inoculation and regulation of microorganisms. The transformation of heavy metals by microorganisms follows the first-order kinetic equation:

[0119] C t =C0e -kt

[0120] Among them C t is the heavy metal conversion amount at time t (mg / kg), C0 is the initial heavy metal content (mg / kg), k is the microbial conversion coefficient (s -1 ), by monitoring the changes in heavy metal content in different time periods, combined with the equation, the transformation efficiency of microorganisms to heavy metals is accurately evaluated to guide the optimization of the remediation process.

[0121] The irrigation water volume and drainage duration calculation model of the water regulation subsystem is precisely designed as follows:

[0122] Irrigation water volume is calculated based on the modified Penman-Monteith formula:

[0123]

[0124] η Where I is the irrigation water volume (m 3),ET0 is the reference crop evapotranspiration (mm / d), K c is the crop coefficient, A is the irrigation area (m 2 ),ρ w is the density of water (kg / m 3 ), Δθ is the change in soil moisture content in the planned wet layer, η is the irrigation water utilization coefficient, this formula takes into account a variety of factors and accurately calculates the amount of irrigation water that meets the soil moisture demand; the drainage time calculation is based on the improved model of Darcy's law:

[0125]

[0126] Where t is the drainage time (h), V is the amount of water to be discharged (m 3 ), K is soil permeability coefficient (m / s), A is drainage area (m 2 ), i is the hydraulic gradient. By real-time monitoring of soil moisture content and hydraulic conditions, the improved model of Darcy's law is used to accurately calculate the drainage time to prevent soil waterlogging.

[0127] The steps of the restoration effect evaluation subsystem mainly include heavy metal removal effect evaluation, soil ecological function restoration evaluation, vegetation community stability consideration and surrounding environmental impact monitoring. Specific embodiment 2:

[0129] like Figure 1-2 As shown, before soil remediation, the following stages should be followed:

[0130] 1. Preparation stage before repair

[0131] Personnel training and safety assurance

[0132] Organize systematic training for all technicians and operators involved in the repair project, covering the operating specifications of each subsystem, key points of equipment maintenance, emergency handling procedures, etc. Ensure that each staff member is not only familiar with the skills required for their job, but also understands the coordination mechanism of the entire repair process, and can respond quickly to emergencies to ensure the continuity and safety of the repair work.

[0133] Formulate a strict safety protection system and equip workers with professional protective equipment, such as dust masks, protective gloves, safety shoes, etc., to deal with harmful substances that may be exposed in soil sampling, material preparation, etc. At the same time, set up obvious safety warning signs at the construction site, plan safe passages, conduct regular safety inspections, and identify potential safety hazards.

[0134] 2. Restoration Implementation Phase

[0135] Material transportation and storage

[0136] For the prepared biodegradable nanocomposites, choose a suitable transportation method to ensure that the materials are not damp, contaminated, or damaged during transportation. Use sealed packaging and control the temperature and humidity of the transportation environment according to the characteristics of the materials. For example, for materials that are sensitive to humidity, the transportation vehicle needs to be equipped with a dehumidification device.

[0137] Establish a special material storage warehouse that is moisture-proof, fire-proof, and insect-proof. Store materials according to type and batch, set up clear identification signs, and record key information such as material entry time, validity period, and quality inspection report. Regularly conduct random inspections on stored materials to ensure that material performance does not deteriorate during storage.

[0138] Construction progress management

[0139] A special project progress management team was set up to formulate a detailed construction progress plan, and to clarify the start and end time, key nodes and responsible persons of each subsystem task in the form of a Gantt chart. On-site inspections were carried out daily against the progress plan, the actual construction progress was recorded, and the repair process was tracked in real time to ensure that the overall repair project was carried out as planned.

[0140] Establish a progress warning mechanism. When the progress of a task lags behind by a certain proportion (such as 10%), an early warning will be automatically triggered to notify the relevant responsible persons to take emergency measures, such as increasing the number of construction personnel, extending the working hours, and deploying spare equipment to ensure construction efficiency.

[0141] 3. Restoration Principle

[0142] Nanomaterial adsorption and fixation principle

[0143] Nanofunctional materials in degradable nanocomposites (such as nano zero-valent iron, nano titanium dioxide, and nano montmorillonite) have high specific surface areas and unique surface chemical properties. Taking nano zero-valent iron as an example, there are a large number of active sites on its surface. When it comes into contact with heavy metal ions in the soil (such as lead, cadmium, mercury, etc.), redox reactions will occur. Zero-valent iron loses electrons and is oxidized, and heavy metal ions gain electrons and are reduced to low-valent states or elemental forms, thereby reducing the mobility and bioavailability of heavy metals and achieving adsorption and fixation of heavy metals.

[0144] Nano-montmorillonite has a layered structure, and its interlayers can adsorb heavy metal ions through ion exchange, trapping heavy metal ions in the interlayer gaps to prevent their diffusion in the soil. At the same time, the biodegradable polymer matrix (such as polylactic acid, polyhydroxyalkanoate, chitosan) provides a dispersion carrier for nano-functional materials, making them evenly distributed in the soil, increasing the chance of contact with heavy metals, and synergistically playing an adsorption and fixation role.

[0145] Principle of Microbial Enhanced Degradation and Transformation

[0146] The introduced specific microbial flora (such as Bacillus, Pseudomonas and Rhodococcus) use the degradable nanocomposites as carbon sources, nitrogen sources and other nutrients for metabolic activities in the soil environment. Microorganisms secrete organic acids such as citric acid and oxalic acid during their growth and reproduction. These organic acids can reduce the pH value of the soil, allowing some heavy metal ions to exist in a dissolved state, increasing their activity and facilitating subsequent conversion.

[0147] Enzymes produced by microorganisms, such as oxidoreductases and hydrolases, can directly act on heavy metal ions, converting them from more toxic forms to less toxic or easily precipitated forms. For example, some enzymes can reduce hexavalent chromium to trivalent chromium, which easily forms chromium hydroxide precipitation under alkaline conditions and is thus removed from the soil solution. At the same time, the decomposition of degradable nanocomposites by microorganisms gradually degrades them into harmless small molecules, further promoting the recovery of soil ecology.

[0148] The synergistic effect of water regulation

[0149] Water is an important medium for material migration and chemical reactions in soil. Appropriate soil moisture content can ensure that degradable nanocomposites are in full contact with heavy metal ions and promote the adsorption and fixation process. When the soil moisture content is too high, it may cause material agglomeration and loss, affecting the repair effect; when the moisture content is too low, it will inhibit microbial activity and hinder chemical reactions.

[0150] The water regulation subsystem calculates the irrigation water volume and drainage time based on real-time monitoring data and preset models, maintains soil moisture content in an appropriate range, and ensures the synergistic effect between nanomaterials, microorganisms and heavy metals. For example, in the early stage of microbial inoculation, appropriately increasing the soil moisture content to 70%-80% of the field water holding capacity is conducive to the colonization and initial metabolism of microorganisms; in the later stage of material degradation, appropriately reducing the moisture content promotes the stability of heavy metal precipitation.

[0151] 4. Restoration Monitoring Phase

[0152] Data Management and Analysis

[0153] Build a unified data management platform to upload all kinds of data collected by the repair process monitoring subsystem to the platform in real time to achieve centralized storage, backup and sharing of data. The data platform has data cleaning and verification functions, automatically identifies and corrects abnormal data, and ensures data accuracy.

[0154] Professional data analysts are arranged to conduct in-depth mining and analysis of monitoring data on a regular basis. Statistical analysis methods and data visualization technology are used to draw trend charts of various data changes, such as the change curve of soil heavy metal content over time, the correlation chart between nanomaterial degradation rate and restoration cycle, etc., to provide an intuitive and scientific basis for the adjustment of restoration strategies.

[0155] 5. Restoration and consolidation stage

[0156] Ecological corridor construction

[0157] Around the restoration area, ecological corridors are planned and constructed in combination with the local ecological pattern. Appropriate local plant species, such as aquatic plants such as reeds and calamus, are selected for the construction of wetland ecological corridors to attract birds, fish and other creatures to inhabit; some vines such as honeysuckle and creepers are added to form an ecological connection zone between the edge of the restoration site and the surrounding natural environment, promoting the recovery and spread of biodiversity and improving the stability of the regional ecosystem.

[0158] During the construction of ecological corridors, attention should be paid to the connection with surrounding farmland, forest land and other ecosystems to avoid the formation of ecological islands. The width and direction of the corridors should be reasonably designed, and ecological nodes such as small ponds and compost pits should be set up according to the topography to provide foraging and breeding places for organisms, thereby enhancing the ecological service function of the ecological corridors.

[0159] 6. Restoration Assessment Phase

[0160] Public participation and feedback

[0161] Before and after the implementation of the restoration project, we actively carried out public participation activities to publicize the hazards of heavy metal pollution in soil, restoration goals and expected results to surrounding residents and community organizations. We collected public opinions and suggestions and answered public concerns through popular science lectures, community announcements, and questionnaires.

[0162] Incorporate public feedback into the restoration effect evaluation system, such as the public's satisfaction with the environmental improvement in the restoration area, the evaluation of the landscape effect of vegetation restoration, etc. Adjust the follow-up restoration management measures in a timely manner based on public feedback to ensure that the restoration project not only meets the ecological and environmental requirements, but also receives recognition and support from the public.

[0163] Through the above optimization and supplementary links, the soil heavy metal remediation workflow driven by degradable nano-composite materials will be further improved, the scientificity, systematicness and sustainability of the remediation project will be improved, and the remediation results will be guaranteed in all aspects. Specific embodiment three:

[0165] like Figure 1-2 As shown, the following are soil heavy metal remediation methods driven by degradable nanocomposites. Specific embodiment four:

[0167] like Figure 1-2 As shown, the following is a detailed hardware composition and hardware description of each subsystem in Example 1:

[0169] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "comprising a reference structure" do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0170] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A soil heavy metal remediation method based on degradable nanocomposite materials, characterized in that: The following steps are involved: S1. Before carrying out soil heavy metal remediation work, a soil remediation system is constructed, and the remediation method is implemented by relying on the soil remediation system for operation, management and regulation; The soil remediation system includes a soil sampling and analysis subsystem, a nanomaterial preparation subsystem, a remediation plan customization subsystem, a contaminated area positioning subsystem, a remediation process monitoring subsystem, a microbial enhancement subsystem, a water regulation subsystem, a vegetation restoration guidance subsystem, an environmental risk assessment subsystem, and a remediation effect assessment subsystem. When the soil remediation system is started, the soil sampling and analysis subsystem collects and detects soil sample information; During operation, the nanomaterial preparation subsystem prepares an adapted degradable nanocomposite material; the remediation solution customization subsystem plans the remediation process according to the soil pollution status and site conditions; the contaminated area positioning subsystem uses the geographic information system to accurately locate the contaminated area; The nanomaterial preparation subsystem adopts three processes of physical blending, in-situ polymerization and sol-gel, combines biodegradable polymer matrix and nano-functional materials, and prepares a degradable nano-composite material with strong adsorption and fixation ability for heavy metals. The biodegradable polymer matrix is ​​selected from polylactic acid, polyhydroxyalkanoate, chitosan, and the nano-functional materials are selected from nano-zero-valent iron, nano-titanium dioxide, and nano-montmorillonite. During the preparation process, the material formula is accurately optimized according to the target heavy metal type, content and soil characteristics; The microbial enhancement subsystem introduces microbial flora, promotes the degradation of degradable nanocomposites and the transformation of heavy metals with the help of microbial metabolic activities, and accelerates the repair process by using organic acids and enzymes produced by microorganisms; the moisture regulation subsystem reasonably arranges irrigation and drainage according to soil moisture content, climatic conditions and repair stage requirements, maintains suitable soil humidity, and ensures the effect of the degradable nanocomposites and heavy metals; when the soil remediation system is started, the soil sampling and analysis subsystem collects and detects soil sample information; the soil heavy metal remediation method based on degradable nanocomposites driven comprises the following steps: S2. After the restoration work is started, the soil sampling and analysis subsystem is linked with the soil detector to collect soil samples at three different depths of 0-20 cm, 20-40 cm and 40-60 cm in the area to be restored. Atomic absorption spectroscopy, inductively coupled plasma mass spectrometry are used to determine the content, morphological distribution and basic physical and chemical properties of soil heavy metals. At the same time, a soil information database is constructed for subsequent query and comparison; S3, updating soil sample data every month, and resampling and analyzing in time within seven days when the soil properties change significantly, including external interference factors such as heavy rainfall and new pollution sources in the surrounding area; preparing the adapted degradable nanocomposite material through the nanomaterial preparation subsystem during operation, the specific steps are: S4. Based on the results of the previous soil sampling and analysis, the nanomaterial preparation subsystem selects appropriate biodegradable polymer matrices and nano-functional materials. When the soil is seriously polluted by lead and cadmium, polyhydroxyalkanoate matrices combined with nano-zero-valent iron functional materials are preferred; when mercury pollution is prominent, chitosan matrices combined with nano-titanium dioxide functional materials are considered; S5. Prepare degradable nanocomposites by uniformly dispersing nanofunctional materials in polymer matrices through physical blending, in-situ polymerization, and sol-gel methods, and use scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy for quality inspection and performance optimization; The remediation solution customization subsystem plans the remediation process according to the soil pollution status and site conditions. The specific steps are as follows: S6. Comprehensive soil sampling and analysis data, site hydrogeological information and pollution source investigation results, the remediation plan customization subsystem formulates a detailed remediation plan, clearly stating that the amount of degradable nanocomposites to be added is 0.5%-5% of the soil mass, the placement method is to spread the application and then till the soil for uniform mixing, and the remediation period is set at 6-24 months according to the degree of pollution; S7. Combine the actual construction conditions and potential risk factors, use numerical simulation software to simulate and predict the implementation effects of different restoration schemes in complex soil environments, compare and analyze the advantages and disadvantages of each scheme, select the best scheme and make fine adjustments according to the actual situation to ensure the feasibility and effectiveness of the scheme; The polluted area positioning subsystem uses the geographic information system to accurately locate the polluted area, and its execution steps are as follows: S8. Collect the topography, land use status and historical satellite image data of the site to be restored and import them into the geographic information system; S9. Using the spatial analysis function of the geographic information system, combined with the heavy metal exceeding standard area information in the soil sampling analysis data, the pollution range is accurately delineated to provide coordinate guidance for targeted remediation. The microbial enhancement subsystem introduces specific microbial flora to promote the degradation of degradable nanocomposites and the transformation of heavy metals with the help of microbial metabolic activities. The specific steps are as follows: S10. According to soil characteristics and restoration goals, select microbial flora from the genera Bacillus, Pseudomonas and Rhodococcus that have the ability to decompose degradable materials and have tolerance and conversion capabilities to heavy metals. At the appropriate stage of the restoration process, inoculate the microbial flora into the soil at a prescribed dose of 100,000-10,000,000 colony-forming units per gram of soil. By monitoring the growth and reproduction of microorganisms and their impact on the restoration effect, adjust the microbial inoculation strategy every two months; The water regulation subsystem arranges irrigation and drainage according to soil moisture content, climate conditions and restoration stage requirements to maintain suitable soil humidity and ensure the effect of the degradable nanocomposite material and heavy metals, and includes the following steps: When it is found that the soil moisture content deviates from the suitable range, the startup subsystem calculates the irrigation water volume and drainage time based on the preset drainage model and combined with real-time meteorological data, accurately executes control instructions through intelligent irrigation and drainage facilities, and monitors soil moisture feedback in real time.

2. The soil heavy metal remediation method based on degradable nanocomposite materials according to claim 1, characterized in that: The repair process monitoring subsystem tracks the indicators of the repair process in real time, specifically: Atomic absorption spectroscopy, inductively coupled plasma mass spectrometry and plasma mass spectrometry are used to monitor the changes in the total amount and effective content of heavy metals in the soil every month, which can directly reflect the effect of heavy metal removal and accurately determine whether the restoration process is in line with expectations; The degradation rate of the degradable nanocomposites was tested every three months using thermogravimetric analysis and differential scanning calorimetry combined with weight loss measurement; The soil pH value is measured by the potentiometric method, the soil organic matter content is measured by the potassium dichromate oxidation method, and the cation exchange capacity is measured by the ammonium acetate exchange method. The physical and chemical properties of the soil are monitored monthly to detect subtle changes in the soil environment in a timely manner, providing a basis for adjusting the restoration strategy; With the help of high-throughput sequencing technology, the soil microbial community structure and diversity are analyzed every six months, and the impact of restoration measures on the soil ecosystem is evaluated from the microbial ecology level.

3. The soil heavy metal remediation method based on degradable nanocomposite materials according to claim 1, characterized in that: The vegetation restoration guidance subsystem promotes vegetation growth in the later stage of restoration and consolidates the restoration results. The operation details are as follows: Based on the local climate, soil type and degree of pollution remediation, local native plant species are prioritized for vegetation restoration. Herbaceous plants include bermudagrass, clover and ryegrass, shrubs include Amorpha fruticosa, Hippophae rhamnoides and Lespedeza bicolor, and trees include poplar, willow and Sophora japonica. In the early stage of vegetation planting, a detailed irrigation plan is formulated according to the growth characteristics of plants. The soil moisture content of herbaceous plants is maintained at 60%-70%, shrubs at 50%-60%, and trees at 40%-50%, and the irrigation amount is dynamically adjusted according to the growth stage of the plants; In case of insufficient soil fertility, apply 5-10 kg of organic fertilizer, 0.1-0.3 kg of nitrogen fertilizer, 0.05-0.15 kg of phosphorus fertilizer, and 0.1-0.2 kg of potassium fertilizer per square meter.

4. The soil heavy metal remediation method based on degradable nanocomposite materials according to claim 1, characterized in that: The environmental risk assessment subsystem pre-evaluates the environmental risks generated during the entire restoration process, including the following key points: For the degradable nanocomposites themselves, acute toxicity tests, chronic toxicity tests and bioaccumulation tests are used to evaluate their potential hazards to soil organisms and surrounding ecosystems, among which the soil organisms are earthworms and nematodes. Consider the water regulation link in the restoration process, simulate extreme climatic conditions, and evaluate the risk of material loss due to poor drainage and the possibility of groundwater contamination caused by excessive irrigation.

5. The soil heavy metal remediation method based on degradable nanocomposite materials according to claim 1, characterized in that: The soil sampling and analysis subsystem comprehensively collects basic soil information at the initial stage of restoration. The operating specifications include: Taking the center of the plot as the reference point, the sampling grid is divided by chessboard or snake sampling method. For plots with an area of ​​less than 1 hectare, the grid size is set to 10 meters × 10 meters; for plots with an area between 1-5 hectares, it is set to 20 meters × 20 meters; when it is larger than 5 hectares, it is set to 30 meters × 30 meters to ensure that the sampling points are evenly distributed and accurately reflect the overall soil pollution status. At each sampling point, the soil is collected in layers strictly according to the three standard depths of 0-20 cm, 20-40 cm and 40-60 cm. The soil layers at the same depth are fully mixed and taken as a sample to avoid sampling errors and provide reliable data support for the formulation of subsequent remediation plans.

6. The soil heavy metal remediation method based on degradable nanocomposite materials according to claim 1, characterized in that: In the nanomaterial preparation subsystem, the key process parameters of physical blending, in-situ polymerization and sol-gel method are precisely controlled as follows: Physical blending method: The stirring speed is controlled at 500-1000 rpm, the stirring time is 30-60 minutes, and the temperature is controlled at 40-60°C according to the material properties; In-situ polymerization method: the initiator concentration is precisely adjusted to 0.5%-2%, the monomer concentration is 20%-40%, the reaction temperature is maintained at 60-80°C, and the reaction time is 4-8 hours; Sol-gel method: The ratio of the precursor hydrolysis rate to the polycondensation reaction rate is controlled at 1:2-1:3, the hydrolysis degree is maintained at 30%-50%, the polycondensation degree is 40%-60%, and the pH value of the reaction system is strictly controlled between 3-5.

7. The soil heavy metal remediation method based on degradable nanocomposite materials according to claim 1, characterized in that: The quantitative relationship between the microbial growth and reproduction dynamics and heavy metal transformation in the microbial enhancement subsystem is as follows: Microbial growth and reproduction follow the Monod equation: Where μ is the rate of change of microbial population over time, μ max is the maximum growth rate, S is the substrate concentration, K s is the saturation constant of microbial growth. The transformation of heavy metals by microorganisms follows the first-order kinetic equation: C t =C0e -kt Among them C t is the heavy metal conversion amount at time t, C0 is the initial heavy metal content, k is the microbial conversion coefficient (s -1 ), by monitoring the changes in heavy metal content in different time periods.

8. The soil heavy metal remediation method based on degradable nanocomposite materials according to claim 1, characterized in that: The irrigation water volume and drainage time calculation model of the water regulation subsystem is precisely designed as follows: Irrigation water volume is calculated based on the modified Penman-Monteith formula: η Where I is the irrigation water volume (m 3 ), ET0 is the reference crop evapotranspiration, K c is the crop coefficient, A is the irrigation area (m 2 ),ρ w is the density of water (kg / m 3 ), Δθ is the change in soil moisture content in the planned wet layer, η is the irrigation water utilization coefficient, and the drainage time calculation is based on the improved model of Darcy's law: Where t is the drainage time (h), V is the amount of water to be discharged (m 3 ), K is the soil permeability coefficient, A is the drainage area (m 2 ), i is the hydraulic gradient. By real-time monitoring of soil moisture content and hydraulic conditions, the improved model of Darcy's law is used to accurately calculate the drainage time to prevent soil waterlogging.

9. The soil heavy metal remediation method based on degradable nanocomposite materials according to claim 1, characterized in that: The steps of the restoration effect evaluation subsystem mainly include heavy metal removal effect evaluation, soil ecological function recovery evaluation, vegetation community stability consideration and surrounding environmental impact monitoring.

Images