A method for ecological restoration of quarry sites based on soil seed bank

Abstract

The invention relates to the field of soil restoration, and discloses a method for ecological restoration of a quarry based on a soil seed bank, comprising the following steps: S1: collecting and constructing a soil seed bank; S2: remediation of a mining area; S3: subsoil treatment; S4: covering a seed bank matrix; S5: covering with imported soil; and S6: vegetation reconstruction. The invention performs ecological restoration on a quarry area based on a soil seed bank, can repair the mine soil, can improve the water holding capacity and nutrient holding capacity of poor sandy soil, increase soil fertility, and provide better living conditions for microbial communities, and improve the absorption efficiency of plants to heavy metal ions; through electric heavy metal ion solidification technology, heavy metals are fixed, their biological effectiveness is reduced, the passivation effect of heavy metals is enhanced, and the biological activity of the soil is improved.

Description

Technical Field

[0001] The present invention relates to the field of soil restoration, and more particularly to a quarry ecological restoration method based on a soil seed bank. Background Art

[0002] After the mining activities in a quarry are completed, the mine land is usually restored and agriculture or forestry is developed. However, quarrying activities cause serious damage to the land, resulting in the disappearance of surface vegetation, destruction of soil structure, and degradation of ecosystem functions.

[0003] Among them, gravel mines that mine gravel and other gravel rocks will carry out large-scale stripping and excavation operations during the mining process. The original surface mature soil is completely removed, and the underlying parent material layer is exposed. These bare ore bodies and gravel parent material soil structures are extremely poor, lacking organic matter and agglomeration structure, which is not conducive to plant growth. Due to the thorough excavation and destruction, the mining area did not retain the original soil seed bank and microbial flora, and could not rely on natural vegetation to recover. The exposed gravel mining area is prone to water loss and leakage, and also lacks a good drainage system, sometimes dry and sometimes flooded. Gravel itself lacks nutrients, the parent material soil in the mining area is barren, and inorganic nutrients are seriously lacking. Some gravel comes from the mineralized zone and contains a certain amount of heavy metal ions, which will be toxic to plant growth.

[0004] At present, ecological restoration of such quarries, especially soil restoration, is an urgent problem to be solved. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a quarry ecological restoration method based on a soil seed bank.

[0006] A method for ecological restoration of a quarry based on a soil seed bank comprises the following steps:

[0007] S1: Collecting and constructing soil seed banks

[0008] Collect and construct native soil seed banks in undisturbed areas of similar vegetation around the mine site;

[0009] S2: Mine area remediation

[0010] Level the mine area, dredge the drainage system, and carry out engineering protection on steep slopes;

[0011] S3: Subsoil treatment

[0012] Improve the exposed gravel parent material at the bottom of the mining area;

[0013] S4: Covering the seed bank matrix

[0014] First, lay a 10-15cm thick layer of natural seed bank soil and plant seed mixed matrix on the subsoil surface;

[0015] S5: Covering with imported soil

[0016] Cover the seed bank matrix with 15-20cm of high-quality foreign mature planting soil or garden soil as a moisture-retaining layer;

[0017] S6: Vegetation Restoration

[0018] Provide closed protection to prevent disturbance, control irrigation, re-sow pioneer herb seeds, accelerate vegetation recovery, re-plant trees and shrubs after 2-3 years, and rebuild a multi-layer vegetation system.

[0019] Preferably: in step S1, collecting and constructing a soil seed bank comprises the following steps:

[0020] S11: Collect natural seed bank soil rich in seeds and microorganisms from the topsoil 5-10 cm deep in undisturbed areas with similar vegetation around the mining area;

[0021] S12: Collect mature seeds of major trees, shrubs and herbs around the mining area, paying special attention to collecting seeds of pioneer species and native plants with strong adaptability;

[0022] S13: Mix the collected natural seed bank soil with the imported planting soil, add appropriate amount of collected native plant seeds according to the desired plant community type, and ensure uniform mixing.

[0023] Preferably: in step S13, a biological agent may be added to the mixed soil to promote the reproduction and activity of beneficial microorganisms in the soil.

[0024] Preferably: in step S3, the subsoil treatment comprises the following steps:

[0025] S31: Apply biochar and clay minerals to the surface of the subsoil in the mining area to improve the water holding capacity and nutrient retention capacity of the poor sandy soil, increase soil fertility, and provide better living conditions for microbial communities;

[0026] S32: Lay low-voltage electrode grids in the subsoil area and plant heavy metal hyperaccumulator-resistant plants. Electrically stimulate plant roots to improve the absorption efficiency of heavy metal ions by plants. Electrically solidify heavy metal ions to fix heavy metals and reduce their bioavailability.

[0027] S33: Apply a combination of nano-minerals and functional microorganisms that have the ability to adsorb and passivate heavy metals to achieve interaction between microorganisms and nano-minerals, enhance the passivation effect of heavy metals, and improve the biological activity of the soil.

[0028] Preferably, in step S32, the heavy metal hyperaccumulator-resistant plants are one or more of kale and Bermuda grass.

[0029] Preferably: in step S33, the nano mineral is one or more of nano iron oxide or nano hydrotalcite.

[0030] Preferably: in step S33, the functional microorganism is one or more of Pseudomonas aeruginosa or pyrite sulfur oxidizing bacteria.

[0031] Preferably, in step S31, the specific steps of applying biochar and clay minerals to the surface layer of the subsoil in the mining area are:

[0032] Before applying biochar, carry out necessary soil preparation operations, including removing large stones and debris, loosening the soil surface, and ensuring that the biochar can be evenly mixed with the soil;

[0033] The application rate of biochar is 5-20 kg per square meter of soil. After mixing the biochar with other amendments, spread it evenly on the soil surface, then plow it and mix it into the soil layer 20-30 cm deep.

[0034] After applying biochar, a layer of mature topsoil is covered, and irrigation and fertilization are carried out to promote microbial colonization and plant growth.

[0035] Preferably, in step S32, the specific steps of laying a low voltage electrode grid in the subsoil area and implanting heavy metal hyperaccumulator-resistant plants are:

[0036] Use inert electrode materials, lay them in the subsoil area, with an electrode spacing of 0.5-1 meter, and the electrodes penetrate 20-30 cm into the soil, covering the main pollution layer, and connect to a DC power supply with a voltage range of 1-5V;

[0037] Select hyperaccumulators with strong tolerance to heavy metals, plant them evenly in the electrode grid area, and during the plant growth period, adjust the voltage and current intensity to ensure that the microcurrent can effectively stimulate root growth without causing excessive stress on the plants. The current density is controlled at 0.01-0.1mA / cm²;

[0038] In the anode area, heavy metal cations will migrate to the cathode, and some heavy metal ions will be absorbed by the plant roots. The pH value around the anode will gradually decrease, forming an acidic environment, which will further promote the dissolution and migration of heavy metals.

[0039] In the cathode area, heavy metal ions are concentrated and fixed due to electrokinetic action. Adding limestone powder or other alkaline materials near the cathode promotes the precipitation and solidification of heavy metals.

[0040] The electrostatic solidification process forms insoluble precipitates of heavy metal ions in the cathode area through electrochemical precipitation, adsorption and chemical complexation, thereby solidifying them in the soil and reducing their bioavailability.

[0041] Preferably, the inert electrode material is one of titanium, platinum or carbon electrode.

[0042] Preferably, in step S33, a combination of nano-minerals and functional microorganisms having the ability to adsorb and passivate heavy metals is applied, and the specific steps are as follows:

[0043] selecting microorganisms and nano-minerals, and co-culturing the selected microorganisms with the nano-mineral materials to form a composite material;

[0044] In the soil area that needs to be repaired, first carry out necessary land preparation and drainage treatment to optimize the growth environment of microorganisms;

[0045] Spread the prepared microorganism and nano-mineral symbiotic composite material evenly on the soil surface, or mix it thoroughly with the soil (to a depth of about 20-30 cm);

[0046] Regularly collect and monitor soil samples, analyze heavy metal concentrations and form changes, and evaluate the remediation effect. Monitoring should also include microbial activity and the distribution of nanomaterials.

[0047] The beneficial effects of the present invention are as follows: the present invention can carry out ecological restoration of the quarrying area based on the soil seed bank, can repair the mine soil, can improve the water holding capacity and nutrient retention capacity of the poor sandy soil, increase soil fertility, and at the same time provide better living conditions for the microbial community.

[0048] Through electric plant root stimulation technology, the absorption efficiency of heavy metal ions by plants is improved, and through electric heavy metal ion solidification technology, heavy metals are fixed and their biological effectiveness is reduced.

[0049] Through the interaction between microorganisms and nano-minerals, the passivation effect of heavy metals is enhanced and the biological activity of the soil is improved.

[0050] Biochar provides a basic environment for improving soil structure and water retention capacity, which is not only beneficial for plant growth but also provides a good foundation for microbial activity.

[0051] Electric plant root stimulation and heavy metal immobilization technology can effectively promote the rapid establishment of plants in improved soils, while combining electric ion immobilization with plant enrichment to enhance the fixation of heavy metals.

[0052] Microbial-driven nanomineral symbiotic remediation technology is combined with biochar and electric systems to further enhance the passivation of heavy metals using the effects of microorganisms and nanomaterials, thereby avoiding their enrichment and toxicity in plant roots.

[0053] Multi-level improvement and stabilization: Biochar and nano-minerals work together to improve soil physical and chemical properties, stabilize the underlying soil, and establish microorganisms and plants simultaneously.

[0054] Double heavy metal fixation: The two-pronged approach of electric ion solidification technology and nano-mineral passivation not only improves the soil's fixation effect on heavy metals, but also reduces their cumulative toxicity in plant roots.

[0055] Strengthening ecosystem resilience: Through the combined action of plants, microorganisms and biochar mixed with clay minerals, the health and ecological balance of the soil are gradually restored and rebuilt, creating conditions for the long-term recovery of vegetation. DETAILED DESCRIPTION

[0056] The subject matter described herein will now be discussed with reference to example embodiments. It should be understood that the discussion of these embodiments is only to enable those skilled in the art to better understand and implement the subject matter described herein, and the functions and arrangements of the elements discussed may be changed without departing from the scope of protection of the contents of this specification. Each example may omit, replace or add various processes or components as needed. In addition, the features described relative to some examples may also be combined in other examples.

[0057] Example 1

[0058] In this embodiment, a quarry ecological restoration method based on a soil seed bank is proposed, comprising the following steps:

[0059] S1: Collecting and constructing soil seed banks

[0060] Collect and construct native soil seed banks in undisturbed areas of similar vegetation around the mine site;

[0061] S2: Mine area remediation

[0062] Level the mine area, dredge the drainage system, and carry out engineering protection on steep slopes;

[0063] S3: Subsoil treatment

[0064] Improve the exposed gravel parent material at the bottom of the mining area;

[0065] S4: Covering the seed bank matrix

[0066] First, lay a 10-15cm thick layer of natural seed bank soil and plant seed mixed matrix on the subsoil surface;

[0067] S5: Covering with imported soil

[0068] Cover the seed bank matrix with 15-20cm of high-quality foreign mature planting soil or garden soil as a moisture-retaining layer;

[0069] S6: Vegetation Restoration

[0070] Provide closed protection to prevent disturbance, control irrigation, re-sow pioneer herb seeds, accelerate vegetation recovery, re-plant trees and shrubs after 2-3 years, and rebuild a multi-layer vegetation system.

[0071] in:

[0072] In step S1, collecting and constructing a soil seed bank includes the following steps:

[0073] S11: Collect natural seed bank soil rich in seeds and microorganisms from the topsoil 5-10 cm deep in undisturbed areas with similar vegetation around the mining area;

[0074] S12: Collect mature seeds of major trees, shrubs and herbs around the mining area, paying special attention to collecting seeds of pioneer species and native plants with strong adaptability;

[0075] S13: Mix the collected natural seed bank soil with the imported planting soil, add appropriate amount of collected native plant seeds according to the desired plant community type, and ensure uniform mixing.

[0076] In step S13, biological agents may be added to the mixed soil to promote the reproduction and activity of beneficial microorganisms in the soil.

[0077] In step S3, the subsoil treatment includes the following steps:

[0078] S31: Apply a mixture of biochar and clay minerals as an amendment to the surface of the subsoil in the mining area to improve the water-holding and nutrient-retention capacity of the poor sandy soil, increase soil fertility, and provide better living conditions for microbial communities.

[0079] Biochar is a stable carbon material produced by pyrolysis of biomass (such as wood, straw, livestock and poultry manure, etc.) and has the following significant characteristics:

[0080] Porous structure: Biochar has abundant pores on its surface and inside, which makes it have strong adsorption capacity and can absorb water, nutrients and organic matter. At the same time, these pores also provide a habitat for microorganisms.

[0081] High Specific Surface Area: Biochar has a large specific surface area, which means it has a large surface area to react with trace elements, nutrients and organic matter in the soil, thereby affecting the chemical balance of the soil.

[0082] Long-term stability: Biochar has high stability in the soil, can continue to work for a long time, and is not easily decomposed by microorganisms.

[0083] pH regulating effect: Biochar is generally alkaline and can neutralize acidic soils, increase soil pH, and make it more suitable for plant growth.

[0084] 1. Specific mechanism of action of biochar

[0085] 1) Improve soil structure:

[0086] The porous structure of biochar helps to reorganize soil particles and form good soil aggregates. These aggregates can enhance the air permeability and water retention of the soil and prevent soil compaction and loss.

[0087] 2) Improve water retention and nutrient retention capacity:

[0088] Biochar pores can absorb and retain large amounts of water, slowing water loss, and it can also absorb nutrients, reducing nutrient leaching. This is particularly beneficial for sandy soils, which usually have poor water retention and are prone to nutrient loss.

[0089] 3) Increase soil fertility:

[0090] Biochar can increase soil fertility by absorbing and releasing nutrients, especially some key plant nutrients such as nitrogen, phosphorus and potassium. In addition, the small amount of nutrients contained in biochar itself can also directly provide necessary nutrients for plants.

[0091] 4) Promote microbial activity:

[0092] The porous structure of biochar provides shelter and living space for soil microorganisms, enhancing their activity and quantity. This microbial activity is essential for soil ecological functions such as organic matter decomposition and nutrient cycling.

[0093] 2. Introduction of stabilizers and synergistic effects

[0094] To further enhance the effects of biochar, you can combine biochar with other types of soil stabilizers:

[0095] 1) Clay minerals (such as bentonite, montmorillonite, etc.):

[0096] These minerals are extremely absorbent and expandable and can be used in conjunction with biochar to increase the water holding capacity of the soil. Clay minerals can also help form stable soil aggregates, further improving soil structure.

[0097] 2) Organic matter (such as compost, humic acid, etc.):

[0098] When organic matter is used in combination with biochar, it can increase the carbon content in the soil, improve the physical properties of the soil, and provide an adequate source of nutrients for soil microorganisms. Substances such as humic acid can also bind to heavy metal ions and reduce the bioavailability of heavy metals.

[0099] 3) pH adjuster (such as limestone powder):

[0100] In acidic soils, pH adjusters such as limestone powder can be added and mixed with biochar to further increase the pH value of the soil, making the soil more suitable for plant growth.

[0101] 3. Implementation steps

[0102] 1) Preliminary soil treatment:

[0103] Before applying biochar, the soil should be prepared, including removing large stones and debris, loosening the soil surface, and ensuring that the biochar can be evenly mixed with the soil.

[0104] 2) Ratio of biochar to stabilizer:

[0105] The ratio of biochar to other stabilizers is determined according to the specific conditions of the soil. Usually, the application amount of biochar is 5-20 kg per square meter of soil, while the application amount of clay minerals, organic matter, etc. needs to be adjusted according to the actual conditions of the soil.

[0106] 3) Mixing and application:

[0107] Mix the biochar with other amendments and spread them evenly on the soil surface. Then till the soil and mix the amendments into the soil layer 20-30cm deep.

[0108] 4) Covering and maintenance:

[0109] If conditions permit, a layer of mature topsoil can be covered after applying biochar, and necessary irrigation and fertilization can be carried out to help microbial colonization and plant growth.

[0110] 4. Effects and long-term management

[0111] 1) Short-term effects:

[0112] Biochar-based soil stabilizer can quickly improve soil structure, increase water retention and nutrient content after application. Vegetation recovery is relatively rapid, and initial vegetation growth is good.

[0113] 2) Long-term effects:

[0114] The stability of biochar means it can remain in the soil for decades or longer, providing a lasting soil improvement effect. The reconstruction of microbial communities also contributes to the long-term health of the soil ecosystem.

[0115] 3) Ongoing Management:

[0116] Although biochar-based soil stabilizers have long-term effects, in order to ensure sustained ecological restoration effects, regular soil quality monitoring is required, and organic matter or fertilizers should be added in a timely manner according to vegetation growth conditions.

[0117] Biochar-based soil stabilizer improvement technology is a comprehensive soil improvement method. Through the synergistic effect of biochar and other stabilizers, it significantly improves the structure, water retention, nutrient content and microbial activity of poor soil. In the ecological restoration of quarries, this technology can effectively solve the problems of poor sandy soil, heavy metal pollution, and structural instability, laying a solid foundation for subsequent vegetation reconstruction and ecological restoration.

[0118] S32: Lay low-voltage electrode grids in the subsoil area and plant heavy metal hyperaccumulator-resistant plants. Electrically stimulate plant roots to improve the absorption efficiency of heavy metal ions by plants. Electrically solidify heavy metal ions to fix heavy metals and reduce their bioavailability.

[0119] 1. Technical background and principles

[0120] 1) Basic principles of electric technology:

[0121] Electrokinetic technology mainly uses the electromotive force generated by the electric field in the soil to drive the migration of pollutants. By inserting electrodes in the soil and applying direct current, charged heavy metal ions can be driven to move toward the electrodes. Heavy metal cations near the anode (such as Pb²⁺, Cu²⁺, Cd²⁺, etc.) will be attracted to the cathode and fixed in the cathode area.

[0122] 2) Principle of plant root stimulation:

[0123] The effect of microcurrent can stimulate the activity of plant roots and enhance the absorption function of the roots. Plant root cells are very sensitive to electric current. Appropriate microcurrent can promote cell metabolism, accelerate root growth, enhance the absorption of water and nutrients, and improve the plant's ability to enrich heavy metal ions.

[0124] 3) Synergistic principle:

[0125] Electric technology can not only directly solidify heavy metal ions in the soil, but also act on plant roots through electric current to enhance the plant's ability to absorb and fix heavy metals. This synergistic effect can improve the removal efficiency of heavy metals while reducing the risk of heavy metal migration.

[0126] 2. Detailed implementation steps

[0127] 1) Laying out the electrode grid

[0128] Electrode selection: Use inert electrode materials such as titanium, platinum or carbon electrodes to ensure that the electrodes are not easily corroded in the soil environment.

[0129] Electrode layout: According to the size of the remediation area and the soil properties, the electrode grid is reasonably laid out. Usually, the electrode spacing is 0.5-1 meter. The electrodes need to be 20-30 cm deep into the soil to cover the main contaminated layer.

[0130] Power connection: Connect a DC power supply with a voltage range of 1-5V to ensure that sufficient electromotive force is generated to drive the migration of heavy metal ions without causing damage to the plant roots.

[0131] 2) Planting heavy metal-resistant plants

[0132] Plant selection: Choose hyperaccumulators that are tolerant to heavy metals, such as kale, bermudagrass or other native heavy metal-tolerant plants. These plants have strong heavy metal absorption and accumulation capabilities.

[0133] Plant planting: Plants should be planted evenly within the electrode grid area, and the planting density should be appropriately increased to increase the contact area between the roots and the soil.

[0134] Current regulation: During the plant growth period, the voltage and current intensity are adjusted to ensure that the microcurrent can effectively stimulate root growth without causing excessive stress to the plant. The current density is generally controlled at 0.01-0.1 mA / cm².

[0135] 3) Electric heavy metal curing process

[0136] Anode action: In the anode area, heavy metal cations will migrate to the cathode, and some heavy metal ions will be absorbed by the plant roots. The pH value around the anode will gradually decrease, forming an acidic environment, further promoting the dissolution and migration of heavy metals.

[0137] Cathodic action: In the cathode area, heavy metal ions are concentrated and fixed due to electrokinetic action. The precipitation and solidification of heavy metals can be promoted by adding limestone powder or other alkaline materials near the cathode.

[0138] Heavy metal solidification: The electrostatic solidification process can form insoluble precipitates in the cathode area through electrochemical precipitation, adsorption and chemical complexation, thereby solidifying heavy metal ions in the soil and reducing their bioavailability.

[0139] 3. Technological advantages and synergies

[0140] 1) Synergy between plants and electric technology:

[0141] Root activation: Electric technology can effectively stimulate the growth of plant roots and enhance the heavy metal enrichment capacity of plants, thus making the phytoremediation process more efficient.

[0142] Simultaneous removal and solidification: While plants absorb heavy metals, electric technology fixes the unabsorbed heavy metal ions in the soil through solidification, preventing them from spreading to other areas and reducing the risk of secondary pollution during the remediation process.

[0143] 2) Optimize soil health:

[0144] This technology not only has a significant effect on the remediation of heavy metal pollution, but can also gradually improve soil health by promoting plant growth and restoring soil ecosystems.

[0145] The electric stimulation of the root system can also enhance the plant's absorption of nutrients, make the nutrients in the soil more fully utilized, and promote rapid plant growth and vegetation recovery.

[0146] 3) Long-term stability:

[0147] Electric heavy metal immobilization technology can fix heavy metals in the soil for a long time, reduce their migration and bioavailability, and thus reduce potential risks to the environment.

[0148] 4. Notes on implementation

[0149] 1) Current control:

[0150] The applied voltage and current must be precisely controlled to ensure that no damage is caused to the plant roots while effectively promoting the migration and fixation of heavy metals.

[0151] 2) Heavy metal monitoring:

[0152] Regularly monitor the concentration distribution of heavy metals in the soil to evaluate the effect of electrostatic fixation and the absorption of heavy metals by plants.

[0153] 3) Environmental factors adjustment:

[0154] Pay attention to adjusting soil moisture, pH value and other environmental factors, which will affect the effectiveness of electric technology and phytoremediation.

[0155] 4) Electrode maintenance:

[0156] Ensure the durability of the electrode material and regularly check the condition of the electrodes to avoid degradation of the repair effect due to corrosion or damage.

[0157] Electric plant root stimulation and electric heavy metal ion solidification technology is an innovative soil remediation technology that combines electric technology with plant remediation to achieve efficient treatment of soil contaminated by heavy metals. Microcurrent can not only stimulate plant root growth and enhance the plant's ability to absorb heavy metals, but also solidify unabsorbed heavy metals in the soil through electrochemical action to prevent their diffusion. This synergistic effect significantly improves the remediation efficiency and has long-term stability, which helps to restore and maintain a healthy soil ecosystem.

[0158] S33: Apply a combination of nano-minerals and functional microorganisms that have the ability to adsorb and passivate heavy metals to achieve interaction between microorganisms and nano-minerals, enhance the passivation effect of heavy metals, and improve the biological activity of the soil.

[0159] 1. Technical background and principles

[0160] 1) The role of microorganisms:

[0161] Bioremediation ability: Microorganisms play an important role in soil remediation. Some microorganisms can produce organic acids, surfactants and other substances through metabolic activities, which can form stable complexes or precipitation with heavy metal ions, thereby reducing the bioavailability of heavy metals. In addition, microorganisms can also convert heavy metals into low-toxic or insoluble forms through reduction.

[0162] Ecological restoration capacity: Microorganisms can promote the decomposition of organic matter, release nutrients needed for plant growth, and enhance the biological activity of the soil, thereby promoting the improvement of soil structure and the restoration of the ecosystem.

[0163] 2) The role of nano mineral materials:

[0164] High specific surface area and strong adsorption: Nano-mineral materials have extremely high specific surface area and strong adsorption capacity, which can effectively adsorb heavy metal ions or other pollutants and reduce their mobility and bioavailability in the soil.

[0165] Chemical passivation: Nano-mineral materials such as nano-iron oxide and nano-hydrotalcite can react with heavy metal ions to form stable precipitates or complexes, thereby passivating heavy metals and reducing their toxicity.

[0166] 3) Synergistic effect of microorganisms and nano-minerals:

[0167] Microorganisms and nano-mineral materials can form a symbiotic system. Nano-materials provide a microenvironment for microorganisms to attach and grow, enhancing their activity and metabolic capacity. In turn, microbial metabolites can promote the dispersion and action of nano-materials, enhancing their passivation and adsorption capabilities. This synergistic effect significantly improves the heavy metal remediation effect.

[0168] 2. Detailed implementation steps

[0169] 1) Select appropriate microorganisms and nanominerals

[0170] Microorganism selection: Choose the appropriate microorganism according to the type of pollution. For example, Pseudomonas aeruginosa is suitable for copper pollution remediation, and pyrite sulfur oxidizing bacteria is suitable for heavy metal remediation such as lead and arsenic.

[0171] Nano mineral selection: Choose appropriate nano mineral materials according to the soil pollution situation. For example, nano iron oxide (Fe2O3) has strong adsorption and passivation capabilities for heavy metal ions such as lead and cadmium, and nano hydrotalcite has a layered structure and can effectively fix a variety of heavy metal ions.

[0172] 2) Preparation of microbial and nano-mineral symbiotic composite materials

[0173] Symbiotic composite: Selected microorganisms are mixed and cultured with nano-mineral materials to form a composite material. Usually, microorganisms will attach and grow on the surface or pores of nanomaterials to form a stable symbiotic system. This symbiotic composite material retains the biological repair function of microorganisms and enhances the physical and chemical repair ability of nanomaterials.

[0174] 3) Application in soil remediation

[0175] Soil treatment: In the soil area that needs to be repaired, necessary land preparation and drainage treatment should be carried out first to optimize the growth environment of microorganisms.

[0176] Composite material application: Spread the prepared microorganism and nano-mineral symbiotic composite material evenly on the soil surface, or mix it with the soil thoroughly (about 20-30 cm in depth). This uniform distribution can ensure that the effects of microorganisms and nanomaterials in the soil are maximized.

[0177] Condition optimization: In order to promote the activity of microorganisms, some organic matter (such as compost, humic acid, etc.) can be appropriately added as a nutrient source. In addition, the pH value, moisture and temperature of the soil need to be controlled to maintain high activity of microorganisms.

[0178] 4) Monitoring and maintenance

[0179] Heavy metal monitoring: Regularly collect soil samples to analyze heavy metal concentrations and form changes and evaluate remediation results. Monitoring should also include microbial activity and the distribution of nanomaterials.

[0180] Microbiome maintenance: The microbiome may change over time, so the activity of specific functional microorganisms needs to be regularly supplemented or enhanced to ensure the continuity of the repair process.

[0181] 3. Technological advantages and synergies

[0182] 1) Strengthen the passivation and adsorption of heavy metals:

[0183] Efficient adsorption of nanomaterials: The high specific surface area and adsorption capacity of nanomineral materials can effectively capture heavy metal ions and prevent their migration in the soil.

[0184] Microbial metabolism: Microorganisms can convert heavy metals into low-toxic or insoluble forms through metabolic activities. Nanomaterials provide a good habitat for these microorganisms and enhance their metabolic capacity.

[0185] 2) Improve soil health and ecological restoration:

[0186] Soil structure improvement: Nano-mineral materials can improve the physical structure of the soil, increase the porosity and water retention capacity of the soil. At the same time, the activity of microorganisms further decomposes organic matter, improving soil fertility and microbial diversity.

[0187] Positive feedback in the ecosystem: As soil health improves, vegetation recovers more quickly, and plant roots work together with microorganisms and nanomaterials to form a positive feedback mechanism, further promoting the recovery of the ecosystem.

[0188] 4. Notes on implementation

[0189] 1) Compatibility of microorganisms and nanomaterials:

[0190] Prior to implementation, small-scale experiments should be conducted to ensure that there are no adverse interactions between the selected microorganisms and nanomaterials and that they can coexist effectively.

[0191] 2) Environmental condition control:

[0192] In order to ensure high activity of microorganisms, it is necessary to control soil conditions such as temperature, humidity, pH, etc. For specific nanomaterials, their stability and effects in different soil environments must also be considered.

[0193] 3) Long-term effect evaluation:

[0194] The long-term effects and environmental impacts of nanomaterials and microorganisms in soil need to be evaluated to ensure the environmental friendliness and sustainability of the technology.

[0195] Microbial-driven nano-mineral symbiotic remediation technology is an innovative soil remediation method that can significantly improve the passivation effect of heavy metals and soil improvement ability by combining microorganisms with specific functions and nano-mineral materials. Nanomaterials provide an ideal habitat for microorganisms and enhance their bioremediation functions, while the metabolic activities of microorganisms promote the effects of nanomaterials, forming an efficient and synergistic remediation system. This technology can effectively address soil remediation issues in heavily polluted areas such as quarries, and provides strong technical support for the restoration of ecosystems.

[0196] Example 2

[0197] This example uses experimental means to verify the improvement effect of biochar-based soil stabilizer improvement technology on sandy soil.

[0198] This experiment aims to verify whether the biochar-based soil stabilizer improvement technology can effectively improve the water holding capacity and nutrient retention capacity of poor sandy soil, increase soil fertility, and provide better living conditions for microbial communities.

[0199] Biochar is a porous carbon material prepared by pyrolysis of organic materials (such as wood, straw, livestock manure, etc.). Its porous structure, high specific surface area and carbon-rich properties give it strong adsorption capacity and water retention, while providing a suitable habitat for soil microorganisms.

[0200] By mixing biochar into sandy soil, the physical structure of the soil can be effectively improved, the water holding capacity and air permeability of the soil can be increased, and the loss of water and nutrients can be reduced. In addition, biochar can provide a rich source of organic carbon and promote microbial activity, thereby increasing soil fertility. The experiment will verify these effects by measuring the water holding capacity, nutrient content and microbial activity of the soil before and after improvement.

[0201] Experimental steps:

[0202] 1. Experimental Preparation

[0203] Soil sampling: Select typical poor sandy soil areas to collect soil samples. The sampling depth is 0-20 cm to ensure that the samples are representative.

[0204] Biochar preparation: Local agricultural waste (such as rice husks and straw) was used as raw materials to prepare biochar by anaerobic pyrolysis. The preparation conditions were 500°C and pyrolysis time was 2 hours. The obtained biochar was crushed to a particle size of 1-2 mm.

[0205] 2. Experimental Design

[0206] The collected sandy soil was divided into two groups: a control group (without biochar addition) and an experimental group (with biochar addition).

[0207] Experimental treatment: Add biochar at 5% of soil mass and mix it with sandy soil. Three replicates were set up for each group.

[0208] Control group treatment: No improvement treatment was performed. Three replicate samples were set up for each group.

[0209] 3. Soil improvement and maintenance

[0210] Mixing treatment: The biochar was evenly mixed into the soil of the experimental group, and water was added to 60% of the field water capacity.

[0211] Curing period: Maintain at room temperature for 4 weeks, keep the soil moist during this period, weigh the soil regularly every week and add water to the initial weight.

[0212] 4. Experimental index determination

[0213] Water holding capacity determination: The maximum water holding capacity of the soil before and after improvement was determined by a soil constant humidity container, and the weight change was recorded to calculate the water holding rate.

[0214] Nutrient content determination: The total nitrogen content of the soil was determined by the Kjeldahl method, the available phosphorus content was determined by the Olsen method, and the available potassium content was determined by flame photometry.

[0215] Microbial activity determination: The total amount and structure of microbial communities in the soil were determined by the phospholipid fatty acid analysis (PLFA) method, and the dehydrogenase activity method was used to determine the soil enzyme activity.

[0216] 5. Data Recording and Analysis

[0217] Record the test results of each group of soil samples, and summarize and analyze the differences between different treatment groups.

[0218] Perform statistical analysis (such as analysis of variance) on the data to determine the significance of biochar in improving sandy soil.

[0219] 6. Experimental equipment

[0220] Constant temperature oven, electronic balance, constant humidity container, Kjeldahl nitrogen determination apparatus, flame photometer, optical microscope, PLFA analyzer, dehydrogenase activity assay reagent, sample collection tools (shovel, sample bag).

[0221] 7. Experimental Results

[0222]

[0223] 8 Experimental results analysis

[0224] Water holding capacity: The maximum water holding capacity of the soil in the experimental group was significantly higher than that in the control group, increasing by about 41%. This indicates that the porous structure of biochar effectively enhances the water retention of sandy soil.

[0225] Nutrient content: The total nitrogen content, available phosphorus content and available potassium content of the experimental group soil were significantly higher than those of the control group. The total nitrogen content increased by 87.5%, the available phosphorus content increased by 82.4%, and the available potassium content increased by 69.2%. This shows that biochar has a significant effect on improving the soil nutrient retention capacity.

[0226] Microbial activity: The total amount of microorganisms and soil dehydrogenase activity in the experimental group were significantly higher than those in the control group. The total amount of microorganisms increased by 70%, and the dehydrogenase activity increased by 94%. This indicates that the presence of biochar provides better living conditions for microbial communities and promotes soil microbial activity.

[0227] 9. Summary

[0228] The results of this experiment verified the significant improvement effect of biochar-based soil stabilizer improvement technology on poor sandy soil. By adding biochar, the water holding capacity, nutrient retention capacity and microbial activity of the soil were significantly improved. Biochar provides an ideal physical structure and chemical environment, which not only improves the physical properties of the soil, but also provides a good habitat for microorganisms, promoting the healthy development of the soil ecosystem.

[0229] Example 3

[0230] This example uses experimental means to verify the repair effects of the electric plant root stimulation and electric heavy metal ion solidification technology.

[0231] 1. Purpose of the experiment

[0232] This experiment aims to verify the remediation effect of electric plant root stimulation and electric heavy metal ion solidification technology on heavy metal contaminated soil.

[0233] Specifically include:

[0234] To evaluate whether electric plant root stimulation technology can improve the efficiency of plant absorption of heavy metal ions.

[0235] Verify the function of electric heavy metal ion immobilization technology in fixing heavy metals in soil and reducing their bioavailability.

[0236] 2. Experimental Principle

[0237] Electric plant root stimulation technology uses microcurrent to stimulate plant roots, enhance their metabolic activity and growth ability, and thus improve the plant's absorption efficiency of heavy metal ions. Under the stimulation of electric current, plant roots will have a stronger ability to adsorb and enrich heavy metal ions in the surrounding environment.

[0238] The electric heavy metal ion fixation technology sets electrodes in the soil and applies an electric field to drive the heavy metal ions to move toward the electrodes. These heavy metal ions are fixed in the soil through electrochemical reactions at the electrodes to form insoluble compounds, thereby reducing the bioavailability of heavy metals and thus reducing their harm to the environment.

[0239] 3. Experimental steps

[0240] 1. Experimental Preparation

[0241] Soil sampling: Collect surface soil (0-20 cm) from mining areas contaminated by heavy metals to ensure that the samples are representative. Detect the initial concentration of heavy metals in the soil (such as lead, cadmium, copper, etc.).

[0242] Plant selection: Choose plants that have the ability to accumulate heavy metals, such as kale or bermudagrass.

[0243] 2. Experimental Design

[0244] Control group: only plants were grown without applying current. Three replicate samples were set up for each group.

[0245] Experimental group 1 (root stimulation): Plants were grown and microcurrent was applied to stimulate the roots. Three replicates were set up for each group.

[0246] Experimental group 2 (root stimulation + heavy metal fixation): Plants were planted, microcurrent was applied to stimulate the roots, and electrodes were set in the soil for heavy metal fixation. Three replicates were set up for each group.

[0247] 3. Electrode setting and current control

[0248] Electrode layout: In experimental group 2, anodes and cathodes were set at a distance of 1 meter. The electrode material was selected as inert material such as titanium alloy, and the electrode was inserted into the soil 20-30 cm deep.

[0249] Current parameters: DC power supply was used, with a current density of 0.05 mA / cm² for root stimulation and 0.1 mA / cm² for heavy metal curing. The current application lasted for 8 weeks, with power on for 12 hours per day.

[0250] 4. Plant growth and heavy metal absorption

[0251] Plant planting: Plants were planted in each treatment group, and plant growth was regularly monitored, including indicators such as plant height, number of leaves, and root length.

[0252] Heavy metal absorption: At the end of the experiment, plant samples were collected and the heavy metal contents in the plants were determined using atomic absorption spectrometry (AAS).

[0253] 5. Evaluation of soil heavy metal fixation effect

[0254] Heavy metal distribution determination: After the experiment, soil samples were collected to detect the total amount of heavy metals in the soil and their distribution in different electrode areas. X-ray fluorescence spectroscopy (XRF) was used to analyze the fixation effect.

[0255] 6. Data Recording and Analysis

[0256] The plant growth data, heavy metal content in plants, and heavy metal distribution in soil of each treatment group were recorded.

[0257] Analysis of variance (ANOVA) was used to analyze the differences among different treatment groups.

[0258] 7. Experimental equipment

[0259] DC power supply (adjustable voltage and current), titanium alloy electrodes (anode and cathode), soil sampling tools (shovel, sample bag), atomic absorption spectrometer (AAS), X-ray fluorescence spectrometer (XRF), electronic balance, plant incubator.

[0260] 8. Experimental Data

[0261]

[0262] 9. Experimental results analysis

[0263] Plant growth: The plant heights of experimental groups 1 and 2 were significantly higher than those of the control group, indicating that microcurrent stimulation enhanced the growth ability of plants. The plant height of experimental group 2 was the highest, indicating that the synergistic effect of electric technology and heavy metal solidification was most beneficial to plant growth.

[0264] Heavy metal absorption efficiency: The heavy metal content in the plants of experimental groups 1 and 2 was significantly higher than that of the control group, especially the heavy metal absorption of experimental group 2 was the largest. This shows that the electric plant root stimulation technology effectively improves the absorption efficiency of heavy metals by plants, and the electric heavy metal solidification technology further increases the effectiveness of heavy metals, allowing plants to absorb more.

[0265] Heavy metal fixation effect: The soil heavy metal fixation rate of experimental group 2 was significantly higher than that of the control group and experimental group 1, especially in the fixation effect of three heavy metals: Pb, Cd and Cu. The experimental results show that the electric heavy metal ion fixation technology has a significant effect in reducing the bioavailability of heavy metals.

[0266] 10. Summary

[0267] The experimental results verified the effectiveness of the electric plant root stimulation and electric heavy metal ion fixation technology. Microcurrent stimulation significantly enhanced the plant's ability to absorb heavy metals, while the electric heavy metal fixation technology successfully fixed the heavy metals in the soil, reducing their bioavailability.

[0268] Example 4

[0269] This example uses experimental means to verify the repair effect of the microbial-driven nano-mineral symbiotic repair technology.

[0270] 1. Purpose of the experiment

[0271] This experiment aims to verify the effect of microbial-driven nano-mineral symbiotic remediation technology, including: evaluating whether the interaction between microorganisms and nano-minerals can enhance the passivation effect of heavy metals. Verify whether this technology can improve the biological activity of soil.

[0272] 2. Experimental Principle

[0273] Microbial-driven nano-mineral symbiotic remediation technology combines the bioremediation ability of microorganisms with the physicochemical passivation of nano-mineral materials. Microorganisms release organic acids and surfactants through metabolic activities, which can enhance the adsorption and passivation effect of nano-minerals on heavy metal ions. At the same time, nano-minerals provide a stable habitat for microorganisms, promoting their growth and activity. This synergistic effect can not only effectively reduce the bioavailability of heavy metals, but also enhance the biological activity of soil.

[0274] 3. Experimental steps

[0275] 1. Experimental Preparation

[0276] Soil sampling: Collect surface soil (0-20 cm) from mining areas contaminated by heavy metals to ensure that the samples are representative. Detect the initial concentration of heavy metals in the soil (such as lead, cadmium, copper, etc.).

[0277] Microbial culture: Select microbial strains that can passivate heavy metals, such as Pseudomonas aeruginosa, and culture them in the laboratory to ensure their activity in the experiment.

[0278] Nano-mineral preparation: Nano-iron oxide (Fe2O3) was selected as the nano-mineral material and prepared by wet chemical precipitation method to ensure that its particle size was in the range of 20-50nm.

[0279] 2. Experimental Design

[0280] Control group: only soil samples were added without adding microorganisms or nano-minerals. Three replicate samples were set up for each group.

[0281] Experimental group 1 (microorganisms): soil was inoculated with microorganisms but no nanominerals were added. Three replicates were set up for each group.

[0282] Experimental group 2 (nanominerals): Nanominerals were added to the soil but no microorganisms were inoculated. Three replicates were set up for each group.

[0283] Experimental group 3 (microorganisms + nano-minerals symbiosis): microorganisms were inoculated and nano-minerals were added to the soil at the same time. Three replicate samples were set up for each group.

[0284] 3. Soil treatment and maintenance

[0285] Mixing treatment: Evenly mix the corresponding microbial solution and nano-minerals into the soil to ensure uniform treatment of each group.

[0286] Curing period: Maintain at room temperature for 8 weeks, add water every week to keep the soil moist, and stir regularly to ensure uniform reaction.

[0287] 4. Experimental index determination

[0288] Determination of the passivation effect of heavy metals: X-ray fluorescence spectroscopy (XRF) was used to determine the total amount and morphological changes of heavy metals in the soil, focusing on the bioavailability of heavy metals after passivation.

[0289] Soil biological activity determination: The total amount and structure of microbial communities in the soil were determined by the phospholipid fatty acid analysis (PLFA) method, and the soil enzyme activity was determined by the dehydrogenase activity method.

[0290] pH and organic carbon content determination: Soil pH was measured using a pH meter, and soil organic carbon content was determined using potassium dichromate titration to assess the effects of microbial activity on soil chemical properties.

[0291] 5. Data Recording and Analysis

[0292] The heavy metal passivation effect, soil biological activity data and soil chemical properties data of each group were recorded.

[0293] Analysis of variance (ANOVA) was used to compare the differences among different treatment groups and evaluate the synergistic effect of microorganisms and nanominerals.

[0294] 6. Experimental equipment

[0295] Constant temperature incubator, pH meter, X-ray fluorescence spectrometer (XRF), phospholipid fatty acid analyzer (PLFA), dehydrogenase activity assay reagent, electronic balance, soil sampling tools (shovel, sample bag).

[0296] 7. Experimental Results

[0297]

[0298] 8. Experimental results analysis

[0299] Heavy metal passivation effect: Experimental group 3 (symbiotic restoration) had the highest reduction rate of heavy metal bioavailability, reaching 75%, significantly higher than other groups. This shows that the synergistic effect of microorganisms and nano-minerals effectively enhanced the passivation effect of heavy metals.

[0300] Total microbial count and enzyme activity: The total microbial count and soil dehydrogenase activity of experimental group 3 were also significantly higher than those of other groups, reaching 180 PLFA and 90 μg TPF / g soil / 24h, respectively. This shows that the symbiotic restoration technology not only improves the microbial activity of the soil, but also enhances the biological function of the soil.

[0301] Soil pH and organic carbon content: The soil pH and organic carbon content of experimental group 3 also increased, with the pH value increasing to 5.7 and the organic carbon content increasing to 1.5%. These results further prove that the synergistic effect of microorganisms and nanominerals has a positive effect on improving soil chemical properties.

[0302] 9. Summary

[0303] The experimental results verified the effectiveness of the microbial-driven nano-mineral symbiotic remediation technology. The interaction between microorganisms and nano-minerals significantly enhanced the passivation effect of heavy metals and significantly improved the biological activity of the soil. The symbiotic remediation technology not only effectively reduced the bioavailability of heavy metals in the soil, but also improved the microbial ecosystem and chemical properties of the soil.

[0304] Example 5

[0305] This example uses experimental means to verify the remediation effect of multi-level synergistic remediation on soil heavy metal pollution.

[0306] 1. Purpose of the experiment

[0307] This experiment aims to verify the synergistic repair effect of the following three technical means:

[0308] Biochar-based soil stabilizers improve soil structure and water retention capacity, providing a good basic environment for plant growth and microbial activities.

[0309] Electric plant root stimulation and heavy metal fixation technology promotes rapid plant establishment in amended soils while enhancing heavy metal fixation through electric fixation.

[0310] Microbial-driven nano-mineral symbiotic remediation technology is combined with biochar and electric systems to further enhance the passivation of heavy metals and reduce the enrichment and toxicity of heavy metals in plant roots.

[0311] 2. Experimental Principle

[0312] This experiment is based on the following principles:

[0313] Biochar-based soil stabilizer: By increasing soil organic matter and improving soil structure, it improves soil water retention and nutrient retention capacity, creating a suitable growth environment for plants and microorganisms.

[0314] Electric plant root stimulation and heavy metal solidification technology: Use microcurrent to stimulate plant roots and enhance the heavy metal absorption capacity of plants. At the same time, the electric field drives heavy metal ions to migrate to the electrode and solidify them in the soil, reducing the biological effectiveness of heavy metals.

[0315] Microbial-driven nano-mineral symbiotic remediation technology: Through the combination of specific functional microorganisms and nano-minerals, the passivation effect of heavy metals is enhanced and the microbial activity of the soil is improved, thereby improving the soil ecosystem.

[0316] 3. Experimental steps

[0317] 1. Experimental Preparation

[0318] Soil sampling: Collect surface soil (0-20 cm) from mining areas contaminated by heavy metals to ensure that the samples are representative. Detect the initial concentration of heavy metals in the soil (such as lead, cadmium, copper, etc.).

[0319] Biochar preparation: Local agricultural waste (such as rice husks and straw) was used as raw materials, and biochar was prepared by anaerobic pyrolysis and crushed to a particle size of 1-2 mm.

[0320] Microbial culture: Select microbial strains that can passivate heavy metals, such as Pseudomonas aeruginosa, and culture them in the laboratory to ensure their activity in the experiment.

[0321] Nanomineral preparation: Nano iron oxide (Fe2O3) was selected as the nanomineral material and prepared by wet chemical precipitation method with a particle size in the range of 20-50 nm.

[0322] 2. Experimental Design

[0323] Control group: only soil samples were added without any treatment. Three replicate samples were set up for each group.

[0324] Experimental group 1 (single treatment - biochar): biochar was added to the soil without current or microorganisms. Three replicates were set up for each group.

[0325] Experimental Group 2 (Single Treatment - Electric Stimulation and Fixation): Electrodes were set in the soil and microcurrent was applied for electric stimulation and heavy metal fixation. Three replicates were set up for each group.

[0326] Experimental group 3 (single treatment - microorganisms and nano-minerals): microorganisms were inoculated in the soil and nano-iron oxide was added. Three replicates were set up for each group.

[0327] Experimental group 4 (synergistic treatment - integrated restoration): combining biochar, electrostimulation and heavy metal immobilization, microbial and nano-mineral symbiotic restoration. Three replicates were set up for each group.

[0328] 3. Treatment and maintenance

[0329] Biochar addition: Biochar was added to experimental groups 1 and 4 at 5% of soil mass.

[0330] Electrode setting and current control: Titanium alloy electrodes were set in experimental groups 2 and 4, with an electrode spacing of 1 meter. A DC power supply was used, and the current density was controlled at 0.05 mA / cm².

[0331] Mixing of microorganisms and nano-minerals: The cultured Pseudomonas aeruginosa solution was evenly mixed with nano-iron oxide and added to experimental groups 3 and 4 at 1% of the soil mass.

[0332] Curing period: Maintain at room temperature for 8 weeks, add water to 60% of the field water holding capacity every week to keep the soil moist.

[0333] 4. Experimental index determination

[0334] Determination of heavy metal passivation effect: X-ray fluorescence spectroscopy (XRF) was used to determine the total amount and form changes of heavy metals in the soil and evaluate the passivation effect.

[0335] Soil biological activity determination: The total amount and structure of microbial communities in the soil were determined by the phospholipid fatty acid analysis (PLFA) method, and the soil enzyme activity was determined by the dehydrogenase activity method.

[0336] Plant heavy metal absorption determination: Atomic absorption spectroscopy (AAS) was used to determine the heavy metal content in plants and evaluate the absorption effect of electric root stimulation.

[0337] Determination of soil water holding capacity and organic carbon content: The water holding capacity of the soil was determined using a constant humidity container, and the soil organic carbon content was determined by potassium dichromate titration.

[0338] 5. Data Recording and Analysis

[0339] The heavy metal passivation effect, soil biological activity, plant heavy metal absorption, soil water holding capacity and organic carbon content data of each group were recorded.

[0340] Analysis of variance (ANOVA) was used to compare the differences among different treatment groups and evaluate the synergistic repair effects of various technical means.

[0341] 6. Experimental equipment

[0342] Constant temperature incubator, DC power supply (adjustable voltage and current), titanium alloy electrodes (anode and cathode), pH meter, X-ray fluorescence spectrometer (XRF), atomic absorption spectrometer (AAS), phospholipid fatty acid analyzer (PLFA), dehydrogenase activity assay reagent, constant humidity container, potassium dichromate titration equipment, electronic balance, soil sampling tools (shovel, sample bag).

[0343] 7. Experimental Results

[0344]

[0345] 8. Experimental results analysis

[0346] Heavy metal passivation effect: The comprehensive remediation group (experimental group 4) had the highest reduction rate of heavy metal bioavailability, reaching 80%, significantly higher than other groups. This shows that the synergistic effect of the three technical means effectively enhanced the passivation effect of heavy metals.

[0347] Total microbial count and enzyme activity: The total microbial count and soil dehydrogenase activity of the comprehensive restoration group were significantly higher than those of other groups, reaching 200 PLFA and 95 μg TPF / g soil / 24h, respectively. This indicates that the comprehensive restoration technology significantly improved the biological activity of the soil.

[0348] Plant heavy metal absorption: The plants in the comprehensive restoration group had the highest Pb absorption, reaching 230 mg / kg, indicating that the electric plant root stimulation technology effectively improved the plant's ability to absorb heavy metals.

[0349] Soil water holding capacity and organic carbon content: The soil water holding capacity and organic carbon content of the comprehensive restoration group were significantly higher than those of other groups, with water holding capacity reaching 30.2% and organic carbon content reaching 1.8%. This further demonstrates that the synergistic effect of biochar and microbial-nanomineral technology on improving soil physical and chemical properties is significant.

[0350] 9. Summary

[0351] The experimental results verified the significant synergistic effect of biochar-based soil stabilizer, electric plant root stimulation and heavy metal solidification technology, and microbial-driven nano-mineral symbiotic remediation technology in the remediation of heavy metal-contaminated soil. The combination of the three technical means not only effectively reduced the bioavailability of heavy metals in the soil, but also significantly improved the microbial activity and water holding capacity of the soil, creating good conditions for the long-term recovery of the ecosystem.

[0352] The above describes an embodiment of the present embodiment, but the present embodiment is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present embodiment, ordinary technicians in this field can also make many forms, all of which are within the protection of the present embodiment.

Claims

1. A quarry ecological restoration method based on soil seed bank, characterized in that: The steps include: S1: Collect and construct soil seed banks; Collect and construct native soil seed banks in undisturbed areas of similar vegetation around the mine site; S2: Mining area remediation; Level the mine area, dredge the drainage system, and carry out engineering protection on steep slopes; S3: Subsoil treatment; Improve the exposed gravel parent material at the bottom of the mining area; S4: Covering seed bank matrix; First, lay a 10-15cm thick layer of natural seed bank soil and plant seed mixed matrix on the subsoil surface; S5: Covering with imported soil Cover the seed bank matrix with 15-20cm of high-quality foreign mature planting soil or garden soil as a moisture-retaining layer; S6: vegetation reconstruction; Closed protection, prevent disturbance, control irrigation, re-sow pioneer herbaceous plant seeds, accelerate vegetation recovery, re-plant trees and shrubs after 2-3 years, and rebuild the multi-layer vegetation system; In step S1, collecting and constructing a soil seed bank includes the following steps: S11: Collect natural seed bank soil rich in seeds and microorganisms from the topsoil 5-10 cm deep in undisturbed areas with similar vegetation around the mining area; S12: Collect mature seeds of major trees, shrubs and herbs around the mining area at the same time; S13: Mix the collected natural seed bank soil with the imported planting soil, add appropriate amount of collected native plant seeds according to the desired plant community type, and ensure uniform mixing; In step S13, a biological agent is added to the mixed soil to promote the reproduction and activity of beneficial microorganisms in the soil; In step S3, the subsoil treatment includes the following steps: S31: Apply biochar mixed with clay minerals to the surface of the subsoil in the mining area; S32: Laying low voltage electrode grids in the subsoil area and planting heavy metal hyperaccumulator-resistant plants; S33: Application of a combination of nanominerals and functional microorganisms with the ability to adsorb and passivate heavy metals; In step S32, the heavy metal hyperaccumulator-resistant plant is one or more of kale and Bermuda grass; In step S32, the specific steps of laying a low voltage electrode grid in the subsoil area and planting heavy metal hyperaccumulator-resistant plants are as follows: Use inert electrode materials, lay them in the subsoil area, with an electrode spacing of 0.5-1 meter, and the electrodes penetrate 20-30 cm into the soil, covering the main pollution layer, and connect to a DC power supply with a voltage range of 1-5V; Select hyperaccumulator plants with strong tolerance to heavy metals and plant them evenly in the electrode grid area.

2. A quarry ecological restoration method based on soil seed bank according to claim 1, characterized in that: In step S33, the nano mineral is one or more of nano iron oxide or nano hydrotalcite.

3. The method for ecological restoration of a quarry based on a soil seed bank according to claim 1, characterized in that: In step S33, the functional microorganism is one or more of Pseudomonas aeruginosa or pyrite sulfur oxidizing bacteria.

4. The method for ecological restoration of a quarry based on a soil seed bank according to claim 1, characterized in that: In step S31, the specific steps of applying biochar and clay minerals to the surface layer of the subsoil in the mining area are: Before applying biochar, the soil should be prepared, which includes removing stones and debris, loosening the soil surface, and ensuring that the biochar can be evenly mixed with the soil; The application rate of biochar is 5-20 kg per square meter of soil. After the biochar is evenly mixed with clay minerals, it is evenly spread on the soil surface and then plowed; After applying biochar, a layer of mature topsoil is covered, and irrigation and fertilization are carried out to promote microbial colonization and plant growth.

5. The method for ecological restoration of a quarry based on a soil seed bank according to claim 1, characterized in that: In step S33, a combination of nano-minerals and functional microorganisms having the ability to adsorb and passivate heavy metals is applied, and the specific steps are as follows: selecting microorganisms and nano-minerals, and co-culturing the selected microorganisms with the nano-mineral materials to form a composite material; In areas where soil restoration is needed, land preparation and drainage treatment are performed to optimize the growth environment for microorganisms; The prepared microorganism and nano-mineral symbiotic composite material is evenly spread on the soil surface.

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