Device and method for repairing cadmium-polluted soil with pasture

Abstract

The invention relates to the field of soil remediation, in particular to a device and method for remedying cadmium-contaminated soil through pasture. The device comprises a main rod and a plurality of elastic nets, cross rods are fixedly connected to the two sides of the elastic nets in the height direction, and the cross rods located at the tops of the elastic nets are fixedly connected with the main rod; the main rod is provided with a hydraulic structure for driving transverse rods on the two sides of the elastic net to get away, an elastic reset piece is arranged in the hydraulic structure, the hydraulic structure is used for enabling the transverse rods on the two sides of the elastic net to get close through the elastic reset piece, and a constant flow valve is arranged at the top of the main rod and communicates with the hydraulic structure. An air pump is arranged on the main rod, and an air release opening is formed in the bottom of the main rod and communicated with the air pump. By adopting the technical scheme, the grass root system is wound on the elastic net through the elastic net, so that the integrity of the grass root system when the grass root system is pulled out is improved.

Description

Technical Field

[0001] The present invention relates to the field of soil remediation, and in particular to a device and method for remediating cadmium-contaminated soil with forage. Background Art

[0002] Cadmium contamination in soil refers to the environmental problem caused by the accumulation of the heavy metal cadmium in the soil, exceeding safety limits, due to human activities such as industrial emissions, mining, wastewater irrigation, and the overuse of fertilizers and pesticides. Cadmium is an extremely toxic heavy metal with high mobility and bioaccumulation. It can be absorbed into the food chain through crops, posing a threat to human health. Long-term exposure can cause kidney damage, osteoporosis, and even cancer. Cadmium pollution also disrupts the ecological balance of the soil, reducing fertility and affecting crop yield and quality. Methods for remediating cadmium contamination include physical, chemical, and bioremediation, but these are costly and time-consuming, making source control and prevention crucial.

[0003] Prior art, such as patent publication number CN109174936A, discloses a method for remediating cadmium-contaminated farmland soil using the forage grass Guimu No. 1. The grass concentrates the cadmium and removes it from the soil by pulling it out. However, during the pulling process, the grass roots are likely to remain in the soil. Since the cadmium is concentrated in the grass, the remaining roots, after decomposition, return the cadmium in the roots to the soil. Summary of the Invention

[0004] To solve the above problems, the present invention provides a device and method for using forage grass to repair cadmium-contaminated soil, which is used to wrap the forage grass roots around the elastic net through an elastic net to improve the integrity of the forage grass roots when they are pulled out.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows: a device for remediating cadmium-contaminated soil with forage grass, comprising a main pole and a plurality of elastic nets, wherein cross bars are fixedly connected to both sides of the elastic nets in the height direction, and the cross bars located at the top of the elastic nets are fixedly connected to the main pole. The main pole is provided with a hydraulic structure for driving the cross bars on both sides of the elastic nets away from each other, and an elastic reset member is provided within the hydraulic structure. The hydraulic structure is used to bring the cross bars on both sides of the elastic net closer together via the elastic reset member. A constant flow valve is provided at the top of the main pole, and the constant flow valve is connected to the hydraulic structure.

[0006] An air pump is provided on the main rod, and a gas release port is provided at the bottom of the main rod, which is communicated with the air pump.

[0007] The above scheme has the following beneficial effects:

[0008] 1. In this solution, a planting pit is first constructed, and an elastic net is placed within it. The soil within the restoration area is then covered to bury the net. Grass is then planted in the soil above the net. After the grass is planted, its roots gradually develop and extend. Once they reach the elastic net, the roots penetrate the mesh and become tightly entangled with it. When the grass is subsequently removed from the soil, the net effectively holds the roots, ensuring they remain intact and remove cadmium from the soil.

[0009] 2. In this solution, a constant-flow valve slowly releases the fluid from the hydraulic structure, causing it to contract under the action of an elastic reset element. This contraction of the hydraulic structure pulls the crossbars closer together, causing the elastic net to contract, shrinking the mesh and tightly aligning with the grass roots. Furthermore, this contraction improves the root distribution of the grass and optimizes its lateral and vertical expansion. The fluid in the hydraulic structure can be a nutrient solution or water, slowly released through the constant-flow valve, enabling irrigation or fertilization similar to drip irrigation.

[0010] 3. In this solution, although the hydraulic structure is driven by an elastic reset element, once the soil becomes compacted, it will increase resistance to the movement of the crossbar, so good soil loosening conditions must be maintained. An air pump can be used for gas injection. Since the gas release port is at the bottom of the main rod, it is located at the bottom of the soil after soil burial. Therefore, when gas is injected, the gas is pumped out from the bottom of the soil, thereby loosening the soil conveniently.

[0011] Furthermore, the bottom of the main rod is an L-shaped structure, and the gas release port is located on the L-shaped structure.

[0012] Beneficial effects: The L-shaped structure can improve the distribution of the gas release port. In addition, when the main pole is subsequently pulled out, the L-shaped structure can support the bottom of the grass, making it less likely to break during the pulling process.

[0013] Furthermore, the air pump is a manual air pump.

[0014] Beneficial effect: Users can inflate the air through a manual air pump, which does not require energy storage devices such as batteries, making it easy to deploy.

[0015] Furthermore, a side of the elastic net away from the bottom of the main rod is inclined away from the main rod.

[0016] Beneficial effects: The tilt of the elastic net can improve the coverage area, allowing for a larger root entanglement coverage area. In addition, it can improve the traction effect when the crossbars are brought closer, thereby pulling the roots of the grass in an oblique upward direction, so that the roots of the grass have a better lateral extension effect.

[0017] Furthermore, the reset direction of the hydraulic structure is from the bottom of the elastic net to the top of the elastic net.

[0018] Beneficial effect: the hydraulic structure is reset only from obliquely downward to obliquely upward, so that the hydraulic structure has a greater effect, thereby being able to pull the roots of the grass laterally.

[0019] A method for repairing cadmium-contaminated soil using forage grass, comprising:

[0020] Step 1: Loosen the soil and build a planting pit. Place the main pole into the planting pit so that the elastic net in the planting pit forms an inverted "eight" shape.

[0021] Step 2: Cover the area to be repaired with soil on the elastic net and plant grass, and water the soil thoroughly;

[0022] Step 3: regularly triggering the air pump to pump out gas from the gas release port to loosen the soil covering the elastic net so as to facilitate the contraction of the hydraulic structure;

[0023] Step 4: When the grass is mature, loosen the soil with an air pump and pull out the main pole together with the elastic net and the grass.

[0024] Beneficial Effects: Cadmium accumulates in the roots of most grasses, so when using grasses for cadmium treatment, special attention must be paid to root treatment. The elastic net allows the grass roots to entangle with it, effectively lifting them out of the soil when the grass is pulled out. The air pump design not only facilitates the loosening of the grass, but also facilitates the contraction of the hydraulic structure.

[0025] Furthermore, the fluid used to generate hydraulic drive in the hydraulic structure is nutrient solution.

[0026] Beneficial effect: The constant flow valve can slowly release the nutrient solution, thereby supplementing the nutrition of the forage grass and increasing its growth.

[0027] Furthermore, in step three, the air pump is periodically triggered to stop after the grass branching period ends.

[0028] Beneficial effect: After the roots of the grass are entangled with the elastic net, the loosening of the soil can be stopped, reducing the workload of manual labor.

[0029] Furthermore, in step 4, the perennial forage grass is pulled out before it overwinters and its leaves wither.

[0030] Beneficial effects: The root system of perennial forage grass is fully developed before wintering or after it turns green again. However, pulling it out when it turns green again means that the grass will wither naturally, returning the cadmium in the leaves to the soil. In addition, due to the obstruction of the main stem, it is not convenient to harvest the grass. Therefore, even perennial forage grass should be pulled out before wintering and before the leaves wither.

[0031] Furthermore, in step 4, the pulled grass is treated with ashing to recover and extract cadmium.

[0032] Beneficial effects: Cadmium-enriched grass cannot be used as feed or fertilizer, as this would cause the cadmium to be re-transmitted along the food chain. Therefore, the pulled grass is treated by ashing to extract and recover the cadmium element.

[0033] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is an axonometric diagram of an embodiment of a device for remediating cadmium-contaminated soil with forage grass according to the present invention;

[0035] Figure 2 This is a schematic diagram of an elastic restoring member of an embodiment of a device for repairing cadmium-contaminated soil with forage grass according to the present invention;

[0036] Figure 3 This is a schematic diagram of the steps of an embodiment of the method for using forage to repair cadmium-contaminated soil according to the present invention.

[0037] The reference numerals in the drawings of the specification include: 1. main rod; 2. elastic net; 3. cross bar; 4. hydraulic structure; 5. constant flow valve; 6. L-shaped structure; 7. manual air pump; 8. gas release port; 9. elastic reset part. DETAILED DESCRIPTION

[0038] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0039] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0040] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0041] The following is further described in detail through specific implementation methods:

[0042] Example 1:

[0043] As attached Figure 1-Figure 3 Figure 1 shows a device for using forage grass to remediate cadmium-contaminated soil, comprising a main pole 1 and several elastic nets 2. Crossbars 3 are bonded and fixed to both sides of the elastic nets 2 in the height direction. The crossbars 3 located at the top of the elastic nets 2 are fixedly connected to the main pole 1 via support rods. The main pole 1 is provided with a hydraulic structure 4 that drives the crossbars 3 on both sides of the elastic nets 2 apart. The hydraulic structure 4 is a hydraulic telescopic rod. An elastic return member 9 is welded and fixed within the hydraulic structure 4. The elastic return member 9 is a spring. The hydraulic structure 4 is used to bring the crossbars 3 on both sides of the elastic net 2 closer together via the elastic return member 9. A constant flow valve 5 is mounted on the top of the main pole 1. The hydraulic circuit of the hydraulic telescopic rod passes through the crossbars 3 and support rods and returns to the main pole 1. The constant flow valve 5 is connected to the hydraulic circuit.

[0044] An air pump is installed on the main rod 1, which is a manual air pump 7. An L-shaped structure 6 is provided at the bottom of the main rod 1. The L-shaped structure 6 is provided with several gas release ports 8. The gas release ports 8 are connected to the air pump, and a waterproof and breathable membrane is bonded and fixed inside the gas release ports 8.

[0045] The side of the elastic net 2 away from the bottom of the main rod 1 is inclined away from the main rod 1. The reset direction of the hydraulic structure 4 is from the bottom of the elastic net 2 to the top of the elastic net 2.

[0046] During use, a planting pit is first constructed, and elastic net 2 is placed within the pit. The soil within the area to be remediated is then covered to bury the net 2. The grass is then planted in the soil above the net 2. After planting, the grass gradually develops its root system, extending continuously. Once the root system reaches the elastic net 2, the root hairs will pass through the mesh of the elastic net 2, becoming tightly entangled with it. When the grass is subsequently removed from the soil, the elastic net 2 effectively holds the grass roots, promoting the integrity of the grass roots as they leave the soil, thereby removing cadmium from the soil.

[0047] The constant flow valve 5 slowly releases the fluid from the hydraulic structure 4, reducing the hydraulic pressure therein, thereby causing the hydraulic structure 4 to contract under the action of the elastic reset member 9. After the hydraulic structure 4 contracts, the crossbars 3 move closer together, driving the elastic net 2 to contract, causing the mesh of the elastic net 2 to shrink, thereby tightly binding to the roots of the grass.

[0048] Furthermore, the contraction of the elastic net 2 improves the root distribution of the grass, optimizing its lateral and vertical expansion. The tilt of the elastic net 2 improves coverage, allowing for a larger root entanglement area. It also enhances the traction effect of the crossbars 3 as they converge, pulling the grass roots diagonally upward for greater lateral root extension.

[0049] At the same time, the fluid in the hydraulic structure 4 can be nutrient solution or clean water, which is slowly released through the action of the constant flow valve 5, so that the nutrient solution or clean water drips into the soil after being released from the constant flow valve 5, thereby irrigating the grass in a manner similar to drip irrigation.

[0050] Although the hydraulic structure 4 is driven by an elastic reset member 9, once the soil becomes compacted, it will increase the resistance to the movement of the crossbar 3, making it difficult to move the crossbar 3. Therefore, the soil needs to be kept loose to a certain extent. The air pump can inject gas. Since the gas release port 8 is at the bottom of the main rod 1, it is located at the bottom of the soil after the soil is buried. Therefore, when the gas is injected, the gas will be pumped out from the bottom of the soil, thereby loosening the soil conveniently. Using a manual air pump 7, the user can trigger it during the early stage of grass care, so there is no need to configure additional power supply equipment for energy supply.

[0051] The L-shaped structure 6 can improve the distribution of the gas release port 8. In addition, when the main rod 1 is subsequently pulled out, the L-shaped structure 6 can support the bottom of the grass, making it less likely for the grass to break during the pulling-out process.

[0052] A method for repairing cadmium-contaminated soil using forage grass, comprising:

[0053] Step 1: loosen the soil and build a planting pit, place the main pole 1 into the planting pit, and make the elastic net 2 in the planting pit form an inverted "eight" shape.

[0054] Step 2: Cover the elastic net 2 with soil from the area to be repaired and plant grass, watering the soil thoroughly. Annual grass is the best choice, and any grass with cadmium-accumulating roots or stems and leaves, such as Sudan grass and ryegrass, can be planted.

[0055] Step three: Trigger the air pump regularly, with intervals of 7-14 days between triggers. Air is pumped out of the air release port 8, loosening the soil covering the elastic net 2 and facilitating the contraction of the hydraulic structure 4. After the grass branching period ends, the air pump does not need to be triggered; the grass can continue to grow until maturity. The fluid used to generate the hydraulic drive within the hydraulic structure 4 is a nutrient solution. As the soil covering the elastic net 2 loosens, the constant flow valve 5 continuously releases small amounts of nutrient solution to replenish the grass.

[0056] Step 4: When the grass is mature, loosen the soil with an air pump, pull out the main pole 1 together with the elastic net 2 and the grass, and recover and extract cadmium from the pulled grass after ashing treatment.

[0057] Most cadmium in grass accumulates in its roots, so when using grass for cadmium pollution treatment, special attention must be paid to treating the grass roots. The elastic net 2 allows the grass roots to entangle with it, effectively pulling them out of the soil when the grass is pulled out. The air pump design not only facilitates loosening the grass but also facilitates the contraction of the hydraulic structure 4.

[0058] Cadmium-enriched grass cannot be used as feed or fertilizer, as this would cause the cadmium to be re-transmitted along the food chain. Therefore, the pulled grass is treated by ashing to extract and recover the cadmium element.

[0059] Example 2

[0060] The difference from the above embodiment is that in step 4, the perennial forage grass is pulled out before the leaves have withered and overwintered.

[0061] The root system of perennial forage grass is fully developed before wintering or after it turns green again, but pulling it out when it turns green again means that the grass will wither naturally, returning the cadmium in the leaves to the soil. In addition, due to the obstruction of the main stem 1, it is not convenient to harvest the grass. Therefore, even perennial forage grass should be pulled out before wintering and before the leaves wither.

[0062] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A device for repairing cadmium-contaminated soil with forage grass, characterized in that: The invention comprises a main rod (1) and a plurality of elastic nets (2). Both sides of the elastic nets (2) in the height direction are fixedly connected with cross bars (3). The cross bars (3) located at the top of the elastic nets (2) are fixedly connected to the main rod (1). The main rod (1) is provided with a hydraulic structure (4) for driving the cross bars (3) on both sides of the elastic nets (2) to move away from each other. The hydraulic structure (4) is provided with an elastic reset member (9). The hydraulic structure (4) is used to bring the cross bars (3) on both sides of the elastic net (2) closer together through the elastic reset member (9). A constant flow valve (5) is provided at the top of the main rod (1). The constant flow valve (5) is communicated with the hydraulic structure (4). An air pump is provided on the main rod (1), and a gas release port (8) is provided at the bottom of the main rod (1), and the gas release port (8) is communicated with the air pump.

2. The device for repairing cadmium-contaminated soil with forage grass according to claim 1, characterized in that: The bottom of the main rod (1) is an L-shaped structure (6), and the gas release port (8) is located on the L-shaped structure (6).

3. The device for repairing cadmium-contaminated soil with forage grass according to claim 2, characterized in that: The air pump is a manual air pump (7).

4. The device for repairing cadmium-contaminated soil with forage grass according to claim 3, characterized in that: The side of the elastic net (2) away from the bottom of the main rod (1) is inclined away from the main rod (1).

5. The device for repairing cadmium-contaminated soil with forage grass according to claim 4, characterized in that: The reset direction of the hydraulic structure (4) is from the bottom of the elastic net (2) to the top of the elastic net (2).

6. A method for repairing cadmium-contaminated soil with forage grass, based on the method of the device for repairing cadmium-contaminated soil with forage grass according to claim 5, characterized in that: include: Step 1: loosen the soil and construct a planting pit, place the main pole (1) into the planting pit, and make the elastic net (2) in the planting pit form an inverted "eight" shape; Step 2: Cover the elastic net (2) with soil in the area to be repaired and plant grass, and water the soil thoroughly; Step 3: regularly triggering the air pump to pump out gas from the gas release port (8) to loosen the soil covering the elastic net (2) so as to facilitate the contraction of the hydraulic structure (4); Step 4: When the grass is mature, loosen the soil with an air pump and pull out the main rod (1) together with the elastic net (2) and the grass.

7. The method for repairing cadmium-contaminated soil with forage according to claim 6, characterized in that: The fluid used to generate hydraulic drive in the hydraulic structure (4) is nutrient solution.

8. The method for repairing cadmium-contaminated soil with forage according to claim 7, characterized in that: In step 3, the air pump is periodically triggered to stop after the grass branching period ends.

9. The method for repairing cadmium-contaminated soil with forage according to claim 8, characterized in that: In step 4, the perennial forage grass is pulled out before it overwinters and its leaves wither.

10. The method for repairing cadmium-contaminated soil with forage according to claim 9, characterized in that: In step 4, the pulled grass is treated with ashing to recover and extract cadmium.

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