A Planted Concrete and Its Application in Slope Restoration under Heavy Metal Pollution

Abstract

This invention provides a vegetation concrete and its application in slope restoration under heavy metal pollution. The vegetation concrete includes a base substrate and a surface substrate. By weight, the base substrate includes 90-110 parts of planting soil, 6-9 parts of cement, 5-7 parts of natural organic materials, 3-4.5 parts of ecological conditioner, 1-3 parts of heavy metal passivator, and 1-3 parts of heavy metal complexing agent. The surface substrate includes 90-110 parts of planting soil, 3.2-4.5 parts of cement, 5-7 parts of natural organic materials, 1.8-2.3 parts of ecological conditioner, 1-3 parts of heavy metal passivator, 1-3 parts of heavy metal complexing agent, and 0.012-0.028 parts of planting seeds. This invention uses the combined action of heavy metal passivating agents and heavy metal complexing agents to passivate and absorb heavy metals in the soil, reducing the activity of heavy metal ions, increasing the soil nutrient content in vegetated concrete, promoting the growth of heavy metal hyperaccumulating plants, and further enhancing the soil and plant's ability to absorb and accumulate heavy metals, thus effectively improving the remediation effect of vegetated concrete.

Description

Technical Field

[0001] This invention belongs to the field of slope protection and ecological restoration technology, specifically relating to a type of vegetation concrete and its application in slope restoration under heavy metal pollution. Background Technology

[0002] my country is a country rich in mineral resources, and its mining industry has developed rapidly, especially after the reform and opening up. However, large-scale development has also brought about ecological and environmental problems. Mining has destroyed large areas of vegetation on mining slopes, stripped topsoil, and especially caused by earthwork excavation, resulting in the loss of habitat conditions. This has led to a series of problems such as reduced biodiversity, soil erosion, and frequent geological disasters, seriously affecting the surrounding environment, landscape, and sustainable development of the project disturbance area. Furthermore, the high heavy metal content in the soil of mining areas also limits the effective implementation of ecological restoration projects.

[0003] Vegetated concrete ecological restoration technology has become an effective means of ecological restoration due to its dual functions of engineering protection and ecological greening, as well as its good sustainability of restoration effects. It has been widely used in various slopes in municipal, road, construction, and mining fields. However, heavy metal pollution often occurs during mineral mining, which seriously affects vegetation growth. After heavy metals enter the soil, they enter the plants around the metal mine through infiltration and leaching, inhibiting the growth and development of plant roots, affecting the absorption and transport of nutrients, interfering with plant metabolism, and impacting plant growth and development. This, in turn, affects the positive succession of vegetation, greatly limiting the application effect of vegetated concrete restoration technology in heavy metal mining areas.

[0004] Current research on the limited application of vegetation concrete in slope restoration mainly focuses on arid and saline-alkali areas, while there is still no good solution to the problem of reduced ecological restoration effect of vegetation concrete under heavy metal pollution. Summary of the Invention

[0005] This invention provides a vegetation concrete and its application in slope restoration under heavy metal pollution, which can effectively improve the slope restoration effect under heavy metal pollution.

[0006] The technical solution of the present invention is a planting concrete, comprising a base substrate and a surface substrate. By weight, the base substrate comprises 90-110 parts planting soil, 6-9 parts cement, 5-7 parts natural organic materials, 3-4.5 parts ecological conditioner, 1-3 parts heavy metal passivator, and 1-3 parts heavy metal complexing agent; the surface substrate comprises 90-110 parts planting soil, 3.2-4.5 parts cement, 5-7 parts natural organic materials, 1.8-2.3 parts ecological conditioner, 1-3 parts heavy metal passivator, 1-3 parts heavy metal complexing agent, and 0.012-0.028 parts planting seeds.

[0007] Furthermore, the natural organic material is one or more of agricultural and forestry waste and / or landscaping waste, obtained after crushing, drying, and screening. Examples include poplar branches, apple branches, elm sawdust, willow sawdust, corn stalks, peanut shells, and wheat husks. The preferred ecological conditioner is the concrete landscaping additive from the patented product of Three Gorges University, patent number ZL01138343.7.

[0008] Furthermore, the greening seeds are selected from one or more of the following: bermudagrass, tall fescue, vetiver grass, alfalfa, and magnolia multiflora.

[0009] Furthermore, the heavy metal passivating agent is one or more of bone char, coconut shell char, apricot kernel char, peach kernel char, wood char, coal-based activated carbon, and straw char; bone char is preferred.

[0010] Furthermore, the heavy metal chelating agent is one or more of potassium dihydrogen phosphate, calcium dihydrogen phosphate, or ammonium dihydrogen phosphate.

[0011] This invention also relates to the application of the aforementioned vegetation concrete in slope restoration under heavy metal pollution.

[0012] Furthermore, the specific operating method includes the following steps:

[0013] S1. Slope cleaning: remove loose materials such as loose stones, topsoil, and roots; disinfect and soak the seeds for planting.

[0014] S2. Prepare the vegetation concrete base material and spray it onto the slope surface. When spraying the base material, pressurized water jets are applied below the nozzle. The thickness of the base material spraying is 70-100mm.

[0015] S3. Prepare the vegetation concrete surface substrate and spray it onto the slope surface covered with the vegetation concrete base substrate. When spraying the substrate, pressurized water jets are applied below the nozzles. The spraying thickness is 15-40mm.

[0016] S4. Irrigate and maintain the slope surface to complete the repair treatment.

[0017] Furthermore, during the disinfection and soaking treatment in S1, the seeds are first soaked in alcohol with a mass concentration of 70%-75% for disinfection, then rinsed with sterile water 3-5 times, and then soaked in gibberellin solution with a mass concentration of 100-125 mg / L for 1.25-1.75 hours.

[0018] Furthermore, the preferred spraying thickness in S2 is 85mm. During the spraying process, the distance between the nozzle and the slope is controlled between 0.6 and 1.1m. The spray is applied perpendicularly to the slope in one pass to the designed thickness. A pressurized water jet is applied to the nozzle during spraying, causing the substrate and water to mix in the air. The output pressure of the spray head is not less than 0.1MPa. The concave areas are sprayed first, followed by the protruding areas. The spraying movement can be in an "S" shape or a spiral motion. The pressure of the pressurized water jet is 0.15–0.25MPa.

[0019] Furthermore, the preferred spraying thickness in S3 is 20mm. Surface spraying should be carried out within 8 hours of the completion of the base course construction. Before spraying, the slope should be thoroughly watered to ensure adhesion between the base course and the surface course. Spraying should be carried out at close range, with the distance between the nozzle and the slope controlled within 0.5m. The output pressure of the substrate should be ≥0.1MPa, and the pressure of the pressurized water column should be 0.15~0.25MPa to ensure uniform seeding.

[0020] Furthermore, the heavy metal is Pb and / or Cd.

[0021] The present invention has the following beneficial effects:

[0022] This invention incorporates a heavy metal passivator and a heavy metal complexing agent into the bottom substrate and the top substrate. The heavy metal passivator can precipitate heavy metals in polluted soil in the form of carbonates, and it can also provide attachment points for the heavy metal complexing agent. This enhances the in-situ passivation and absorption capacity of both agents for heavy metals in the soil, significantly reducing the heavy metal content in the soil and increasing above-ground and below-ground biomass, thus effectively improving the soil environmental quality.

[0023] Compared with traditional dry spraying processes, this invention, during the spraying of the base and surface substrates, involves spraying the substrate from the nozzle at an output pressure of not less than 0.1 MPa, supplemented by pressurized water jets to mix it with water in the air, and spraying perpendicular to the slope. This reduces dust concentration in the construction area, improves the uniformity of the substrate, and mitigates the flow of materials on the slope. After spraying, drip irrigation is used to maintain soil moisture, accelerating the hydrolysis of heavy metal complexing agents in the substrate, promoting the electrostatic adsorption of heavy metal passivating agents, facilitating the combination of passivating agents and complexing agents, providing more adsorption sites for heavy metal ions, reducing the amount of adsorbed heavy metals released, and making it more conducive to the formation of fixed-structure precipitation of Pd and Cd, further promoting the fixation of heavy metal ions in the soil.

[0024] Bone char is the preferred heavy metal passivating agent due to its high organic content, which increases the amount of organically bound heavy metals in the soil. Furthermore, its porous nature allows it to adsorb heavy metal ions in the soil, reducing their activity and providing more space for plant root growth, thus offering more readily available nutrients. When the heavy metal complexing agent is mixed into the vegetated concrete slope protection substrate, it promotes the leaching of heavy metals such as Pb and Cd from the contaminated soil and the release of PO from the complexing agent. 3- 4. The reaction generates phosphate mineral precipitates with very low solubility, which is beneficial for the fixation of heavy metals in the soil by heavy metal chelating agents. It promotes the hyperaccumulation of heavy metals and the growth of resilient slope protection plants such as bermudagrass, tall fescue, vetiver grass, alfalfa, and magnolia, further enhancing the soil and plant's ability to absorb and accumulate heavy metals, thereby improving the restoration effect of vegetation-concrete slopes under heavy metal pollution. Detailed Implementation

[0025] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are only for illustrating the present invention and should not be regarded as limiting the scope of the present invention.

[0026] Example 1

[0027] A method for improving the restoration effect of vegetated concrete slopes under heavy metal pollution, the method comprising the following steps:

[0028] Step 1: Slope cleaning: Remove loose materials such as loose stones, loose soil, and loose roots;

[0029] Step 2: Seed pretreatment for greening: Select high-quality, plump seeds of slope protection plants with high heavy metal accumulation and strong stress resistance. In this example, Bermuda grass and alfalfa seeds were selected. The seeds were disinfected by soaking in 75% alcohol, then rinsed three times with sterile water, and then soaked in 125mg / L gibberellin solution for 1.5h.

[0030] Step 3: Preparation of vegetation concrete base substrate: The substrate includes the following materials by weight: 90 parts planting soil, 6 parts cement, 5 parts natural organic materials (elm wood chips and poplar branches), 3 parts ecological conditioner (concrete greening additive in ZL01138343.7), 1 part heavy metal passivating agent (straw charcoal), and 1 part heavy metal complexing agent (potassium dihydrogen phosphate). Mix the ingredients thoroughly to obtain the vegetation concrete base substrate.

[0031] Step 4: The vegetation concrete base material obtained in Step 2 is sprayed onto the slope surface using a spraying machine at a distance of 1.0m perpendicular to the slope surface and with the output pressure of the spraying head at 0.12MPa, supplemented by a pressurized water column of 0.15MPa. The spraying thickness is 70mm.

[0032] Step 5: Preparation of the vegetation concrete surface substrate: The substrate includes the following materials by weight: 90 parts planting soil, 3.2 parts cement, 5 parts natural organic materials (elm wood chips and poplar branches), 1.8 parts ecological conditioner (concrete greening additive in ZL01138343.7), 1 part heavy metal passivating agent (straw charcoal), 1 part heavy metal complexing agent (potassium dihydrogen phosphate), and 0.016 parts pretreated greening seeds. Mix thoroughly to obtain the vegetation concrete surface substrate.

[0033] Step 6: Slope surface vegetation concrete surface substrate spraying: Before spraying, spray the slope surface with water to ensure the adhesion between the base layer and the surface layer. The vegetation concrete surface substrate prepared in Step 4 is sprayed onto the slope surface covered with vegetation concrete base substrate using a spraying machine at a distance of 0.5m perpendicular to the slope surface and with the output pressure of the spraying head at 0.1MPa, supplemented by a pressurized water column of 0.15MPa. The spraying thickness is 15mm.

[0034] Step 7: Maintenance: Water the slope surface for maintenance and moisture retention.

[0035] Example 2

[0036] A method for improving the restoration effect of vegetated concrete slopes under heavy metal pollution, the method comprising the following steps:

[0037] Step 1: Slope cleaning: Remove loose materials such as loose stones, loose soil, and loose roots;

[0038] Step 2: Seed pretreatment for greening: Select high-quality, plump seeds of slope protection plants with heavy metal hyperaccumulation and strong stress resistance. In this example, tall fescue and magnolia multiflora seeds are selected. Then, the seeds are soaked in 75% alcohol for disinfection, rinsed three times with sterile water, and then soaked in 125mg / L gibberellin solution for 1.5h.

[0039] Step 3: Preparation of vegetation concrete base material: including the following materials by weight: 100 parts planting soil, 7 parts cement, 6 parts natural organic materials apple branches and wheat husks, 3.5 parts ecological conditioner (same as in Example 1), 3 parts bone char heavy metal passivating agent, and 1 part heavy metal complexing agent potassium dihydrogen phosphate and calcium dihydrogen phosphate. Mix evenly to obtain the vegetation concrete base material.

[0040] Step 4: The vegetation concrete base material obtained in Step 2 is sprayed onto the slope surface using a spraying machine at a distance of 1.0m perpendicular to the slope surface and with the output pressure of the spraying head at 0.12MPa, supplemented by a pressurized water column of 0.15MPa. The spraying thickness is 85mm.

[0041] Step 5: Preparation of the vegetation concrete surface substrate: The substrate includes the following materials by weight: 100 parts planting soil, 3.5 parts cement, 6 parts natural organic materials (apple branches and wheat husks), 1.8 parts ecological conditioner, 2 parts bone char (heavy metal passivator), 1 part potassium dihydrogen phosphate and calcium dihydrogen phosphate (heavy metal complexing agents), and 0.016 parts pretreated greening seeds. Mix the ingredients thoroughly to obtain the vegetation concrete surface substrate.

[0042] Step 6: Slope surface vegetation concrete surface substrate spraying: Before spraying, spray the slope surface with water to ensure the adhesion between the base layer and the surface layer. The vegetation concrete surface substrate prepared in Step 4 is sprayed onto the slope surface covered with vegetation concrete base substrate using a spraying machine at a distance of 0.5m perpendicular to the slope surface and with the output pressure of the spraying head at 0.1MPa, supplemented by a pressurized water column of 0.15MPa. The spraying thickness is 20mm.

[0043] Step 7: Maintenance: Water the slope surface for maintenance and moisture retention.

[0044] Example 3

[0045] A method for improving the restoration effect of vegetated concrete slopes under heavy metal pollution, the method comprising the following steps:

[0046] Step 1: Slope cleaning: Remove loose materials such as loose stones, loose soil, and loose roots;

[0047] Step 2: Seed pretreatment for greening: Select high-quality, plump seeds of slope protection plants with heavy metal hyperaccumulation and strong stress resistance. In this example, vetiver grass and alfalfa seeds are selected. The seeds are then disinfected by soaking in 75% alcohol, rinsed three times with sterile water, and then soaked in 125mg / L gibberellin solution for 1.5h.

[0048] Step 3: Preparation of vegetation concrete base material: including the following materials by weight: 110 parts planting soil, 9 parts cement, 7 parts natural organic materials (corn stalks and peanut shells), 4.5 parts Runzhi ecological conditioner, 3 parts heavy metal passivating agent (coal-based activated carbon), and 3 parts heavy metal complexing agent (ammonium dihydrogen phosphate). Mix evenly to obtain the vegetation concrete base material.

[0049] Step 4: The vegetation concrete base material obtained in Step 2 is sprayed onto the slope surface using a spraying machine at a distance of 1.0m perpendicular to the slope surface and with a spraying head output pressure of 0.12MPa, supplemented by a pressurized water column of 0.15MPa. The spraying thickness is 100mm.

[0050] Step 5: Preparation of the vegetation concrete surface substrate: The substrate includes the following materials by weight: 110 parts planting soil, 3.5 parts cement, 7 parts natural organic materials (corn stalks and peanut shells), 2.3 parts Runzhi ecological conditioner, 3 parts coal-based activated carbon (heavy metal passivator), 3 parts ammonium dihydrogen phosphate (heavy metal complexing agent), and 0.016 parts pretreated greening seeds. Mix the ingredients thoroughly to obtain the vegetation concrete surface substrate.

[0051] Step 6: Before spraying, spray water on the slope to ensure the adhesion between the base layer and the surface layer. The vegetation concrete surface layer substrate prepared in Step 4 is sprayed onto the slope surface covered with vegetation concrete base layer substrate by spraying machine at a distance of 0.5m perpendicular to the slope surface and at a spray head output pressure of 0.1MPa, supplemented by a pressurized water column of 0.15MPa. The spraying thickness is 40mm.

[0052] Step 7: Maintenance: Water the slope surface for maintenance and moisture retention.

[0053] Comparative Example 1

[0054] Compared with Example 2, no heavy metal passivating agent was added in steps 3) and 5), while the other steps and parameters were the same as in Example 2.

[0055] Comparative Example 2

[0056] Compared with Example 2, no heavy metal complexing agent was added in steps 3) and 5), while the other steps and parameters were the same as in Example 2.

[0057] Comparative Example 3

[0058] Compared with Example 2, in steps 4) and 6), pressurized water jets were not used during the spraying of the base substrate and the surface substrate.

[0059] Comparative Example 4:

[0060] Compared with Example 2, the spray head output pressure during the spraying process of the base substrate and the surface substrate in steps 4) and 6) is 0.05 MPa.

[0061] control group

[0062] Compared with Example 2, no heavy metal passivating agent or heavy metal complexing agent was added in steps 3) and 5), and the other steps and parameters were the same as in Example 2.

[0063] The above-described embodiments, comparative examples, and control group experimental schemes were followed. After 90 days of project implementation, the pH value of the soil samples was tested using the potentiometric method, and the available concentrations of heavy metals Pb and Cd in the soil samples were tested using atomic absorption spectrophotometry. The samples were dried and weighed, and the aboveground and belowground biomass were measured, as shown in Tables 1 and 2 below.

[0064] Table 1

[0065]

[0066] Table 2

[0067]

[0068]

[0069] As shown in the table above, after 90 days of treatment with this method under heavy metal pollution, the content of heavy metals Pd and Cd in the soil decreased significantly. The best passivation efficiency for Pd and Cd was 72.87% and 75.97%, respectively. It also increased the aboveground biomass by 35.65% and the underground biomass by 51.02%, effectively improving the restoration effect of vegetation concrete slopes under metal pollution.

[0070] The above embodiments are merely preferred technical solutions of the present invention and should not be considered as limitations on the present invention. The embodiments and features described in these embodiments can be arbitrarily combined without conflict. The scope of protection of the present invention should be limited to the technical solutions described in the claims, including equivalent substitutions of the technical features described in the claims. That is, equivalent substitutions and improvements within this scope are also within the scope of protection of the present invention.

Claims

1. The application of vegetation concrete in slope restoration under heavy metal pollution, characterized in that, The vegetation concrete comprises a base substrate and a surface substrate. By weight, the base substrate comprises 90-110 parts planting soil, 6-9 parts cement, 5-7 parts natural organic materials, 3-4.5 parts ecological conditioner, 1-3 parts heavy metal passivator, and 1-3 parts heavy metal complexing agent; the surface substrate comprises 90-110 parts planting soil, 3.2-4.5 parts cement, 5-7 parts natural organic materials, 1.8-2.3 parts ecological conditioner, 1-3 parts heavy metal passivator, 1-3 parts heavy metal complexing agent, and 0.012-0.028 parts planting seeds. The specific repair procedure includes the following steps: S1. Slope cleaning: remove loose materials such as loose stones, topsoil, and roots; disinfect and soak the seeds for planting. S2. Prepare the vegetation concrete base substrate and spray it onto the slope surface. When spraying the substrate, a pressurized water column is applied below the nozzle. The thickness of the substrate sprayed is 70-100mm. During the spraying process, the distance between the nozzle and the slope surface is controlled at 0.6~1.1m. The output pressure of the substrate is ≥0.1MPa, and the pressure of the pressurized water column is 0.15~0.25MPa. S3. Prepare the vegetation concrete surface substrate and spray it onto the slope surface covered with the vegetation concrete base substrate. When spraying the substrate, a pressurized water column is applied below the nozzle. The spraying thickness is 15-40mm. The distance between the nozzle and the slope surface is controlled within 0.5m during spraying. The output pressure of the substrate is ≥0.1MPa, and the pressure of the pressurized water column is 0.15~0.25MPa. S4. Irrigate and maintain the slope surface to complete the repair treatment.

2. The application according to claim 1, characterized in that: The natural organic material is one or more of agricultural and forestry waste and / or landscaping waste, which is obtained after crushing, drying and screening.

3. The application according to claim 1, characterized in that: The greening seeds are selected from one or more of the following: bermudagrass, tall fescue, vetiver grass, alfalfa, and magnolia multiflora.

4. The application according to any one of claims 1 to 3, characterized in that: The heavy metal passivating agent is one or more of the following: bone char, coconut shell char, apricot kernel char, peach kernel char, wood char, coal-based activated carbon, and straw char.

5. The application according to any one of claims 1 to 3, characterized in that: The heavy metal passivating agent is bone char.

6. The application according to any one of claims 1 to 3, characterized in that: The heavy metal chelating agent is one or more of potassium dihydrogen phosphate, calcium dihydrogen phosphate, or ammonium dihydrogen phosphate.

7. The application according to claim 1, characterized in that: During disinfection and seed soaking in S1, the seeds are first soaked in 70%-75% alcohol for disinfection, then rinsed with sterile water 3-5 times, and then soaked in a 100-125 mg / L gibberellin solution for 1.25-1.75 hours.

8. The application according to claim 1, characterized in that: Spraying in S3 should be carried out within 8 hours after the completion of the base substrate construction in S2. The slope should be sprayed with water once before spraying.

9. The application according to claim 1, characterized in that: The heavy metals mentioned are Pb and / or Cd.

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