Three-dimensional soil column leaching system with temperature control and stratified sampling functions and operation method

Abstract

The invention relates to the technical field of natural soil leaching tests, and discloses a three-dimensional soil column leaching system with temperature control and stratified sampling functions and an operation method.The three-dimensional soil column leaching system comprises a simulated rainfall leaching unit, an assembled soil column module, a temperature control system and a percolate collecting unit; the simulated rainfall leaching unit realizes uniform spraying of leaching liquid, the assembled soil column module realizes three-dimensional in-situ sampling through a plurality of groups of sampling interfaces which are longitudinally and radially arranged on the side wall, the temperature control system accurately regulates and controls the experimental temperature, and the percolate collection unit completes timed and quantitative collection. According to the invention, multiple layers and multiple columns of sampling interfaces are arranged on the side wall of the model box in a systematized and gridding manner, three-dimensional space sampling is realized in a single box body structure, and the design allows researchers to synchronously obtain migration data and samples of pollutants in the vertical, radial and circumferential directions on the premise of not damaging a soil body structure; and a technical support is provided for revealing spatial heterogeneity distribution and dominant flow paths of pollutants in soil.

Description

Technical Field

[0001] This invention relates to the field of natural soil leaching testing technology, and in particular to a three-dimensional soil column leaching system and its operation method with temperature control and stratified sampling functions. Background Technology

[0002] Soil column testing is a core method for studying soil hydrological processes and pollutant migration behavior in agriculture, forestry, water conservancy, and the environment. In industrial activities such as mining and smelting, large amounts of heavy metals enter the soil environment through multiple pathways, forming complex pollution. Their migration and transformation are dynamically regulated by multiple factors such as pH, temperature, and moisture, exhibiting significant spatiotemporal heterogeneity. Existing leaching devices still have several significant shortcomings: most devices cannot simulate the impact of temperature changes on pollutant migration behavior; traditional devices mostly adopt an integrated, fixed vertical column structure, which can only collect leachate from the bottom and cannot achieve in-situ sampling and analysis of soil layers at different depths; and they generally lack three-dimensional spatial sampling capabilities.

[0003] Existing soil column leaching devices generally have the following shortcomings:

[0004] 1. Inadequate temperature control capability: Most equipment only operates under constant temperature conditions and cannot simulate the impact of temperature changes caused by seasons and regions on the migration behavior of pollutants in the actual environment.

[0005] 2. Limited sampling dimensions and lack of three-dimensional migration information: Traditional devices often adopt an integrated cylindrical or square column structure, and the leachate can only be collected uniformly from the bottom of the column. This design cannot obtain the migration information of pollutants at different depths in the vertical direction and at different radial positions in the horizontal direction; it cannot achieve in-situ, layered sampling in three-dimensional space, and it is difficult to fully capture the spatiotemporal distribution and dynamic transformation patterns of pollutants in the soil profile. Summary of the Invention

[0006] To overcome the above deficiencies, this invention provides a three-dimensional soil column leaching system and operation method with temperature control and stratified sampling functions, which realizes precise temperature control, three-dimensional in-situ stratified sampling, and accurate analysis of pollutant migration and transformation patterns.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: a three-dimensional soil column leaching system and operating method with temperature control and stratified sampling functions, comprising:

[0008] The simulated rainfall leaching unit includes a storage container for storing leaching liquid, a peristaltic pump for precisely pumping the liquid, and a water distributor for uniformly spraying the leaching liquid onto the surface of the soil column.

[0009] An assemblable soil column module includes a base, a model box set on the base, a porous support plate placed at the bottom of the model box, and a square liquid collection tray located below the porous support plate; the side wall of the model box is provided with multiple sets of sampling interfaces for sampling along the longitudinal and radial directions.

[0010] The temperature control unit includes a heating component attached to the outer wall of the model box, and a temperature control component electrically connected to the heating component for precise temperature control;

[0011] The exudate collection unit includes multiple sets of measuring vessels for collecting liquid; the measuring vessels are connected to the outlet of the square collection tray via conduits, or to the sampling interface on the side wall of the model box.

[0012] As a further description of the above technical solution: the simulated rainfall filtration unit also includes pipe one and pipe two. The outlet of the liquid storage container is connected to the inlet of the peristaltic pump through pipe one, and the outlet of the peristaltic pump is connected to the water distributor through pipe two.

[0013] As a further description of the above technical solution: the exudate collection unit also includes pipe three and pipe four, and multiple sets of measuring vessels are provided, one set of which is connected to the outlet of the square collection tray through pipe three, and the other sets are connected to the sampling interface through pipe four.

[0014] As a further description of the above technical solution: each sampling interface is equipped with an openable and closable plug valve.

[0015] As a further description of the above technical solution: the model box is a hollow cuboid with openings at the top and bottom, with a length of 30cm, a width of 20cm, a height of 25cm, and a wall thickness of 1cm. One set of opposite sidewalls of the model box is uniformly provided with three layers of sampling interfaces along the longitudinal direction, and another set of opposite sidewalls is uniformly provided with two rows of three layers of sampling interfaces along the longitudinal direction. Within the same row, the vertical distance between adjacent sampling interfaces is 5cm, the height of the bottom interface from the base of the box is 5cm, and the horizontal distance between columns is 10cm.

[0016] As a further description of the above technical solution: the diameter of the porous support plate is 2.5mm.

[0017] As a further description of the above technical solution: the assemblable soil column module also includes permeable stones, which are laid on top of the soil in the model box.

[0018] As a further description of the above technical solution: the base and the square liquid collection tray are detachably sealed and connected by a flange, and the model box and the base are fitted together by a slot and reinforced by a quick locking mechanism.

[0019] As a further description of the above technical solution: the heating component is a heating plate, which is evenly attached to the four outer walls of the model box; the temperature control component is a PID temperature controller, whose temperature sensor probe can be inserted into the soil of the model box.

[0020] The operation method of a three-dimensional soil column leaching system with temperature control and stratified sampling functions includes the following steps:

[0021] Step 1: Assemble the soil column module. The base and the model box are sealed and connected by flanges and sealing rings. The base and the square liquid collection tray are coupled to each other by slot embedding and quick locking mechanism. The porous support plate is installed at the bottom of the model box to form a complete sealed leaching system. The heating component is installed on the outer wall of the model box.

[0022] Step 2: Prepare the target solution according to the experimental requirements, inject it into the storage container, and use a peristaltic pump to set the required leaching flow rate;

[0023] Step 3: Control the temperature of the simulation chamber to the required temperature for the experiment using the temperature control component, pour the prepared contaminated soil into the model chamber in layers, and lay permeable stones on top of the contaminated soil;

[0024] Step 4: Start leaching. Spray the water evenly onto the surface of the contaminated soil using a water distributor. During the experiment, collect the leachate from different time and space dimensions into the corresponding measuring vessels by opening the stopcock valve at a specific position on the side wall of the model box and connecting the liquid guide tube.

[0025] Step 5: After the test is completed and the leachate is sampled, first loosen the fastening device on the side wall of the model box and place the model box horizontally on the sampling platform; then sample each soil layer in sequence through the preset sampling interface. When sampling, use a sampler to cut soil samples radially in layers.

[0026] The present invention has the following beneficial effects:

[0027] 1. In this invention, three-dimensional spatial sampling is achieved in a single-unit box structure by systematically and griddedly arranging multiple layers and columns of sampling interfaces on the side wall of the model box. This design allows researchers to simultaneously obtain vertical, radial and circumferential migration data and samples of pollutants without damaging the soil structure, providing technical support for revealing the spatial heterogeneity distribution and dominant flow path of pollutants in the soil.

[0028] 2. In this invention, by combining the external wall-attached heating component with a high-precision temperature controller, dynamic and precise control of the internal temperature of the soil column is achieved. This can effectively simulate temperature scenarios under different seasons and geographical climate conditions, greatly improving the environmental realism and data extrapolation value of the experiment, and making up for the shortcomings of existing devices that cannot assess the impact of temperature changes on pollutant migration.

[0029] 3. In this invention, leachate chemical data and soil pollutant distribution data in three-dimensional space can be acquired simultaneously, providing an unprecedented high-resolution, multi-dimensional dataset for constructing and validating pollutant migration and transformation models, which strongly supports the research and development of precise soil pollution risk assessment and remediation technologies. Attached Figure Description

[0030] Figure 1 A structural schematic diagram of a three-dimensional soil column leaching system and its operation method, which has temperature control and stratified sampling functions;

[0031] Figure 2 This is a detailed schematic diagram of the simulation chamber.

[0032] Legend:

[0033] 1. Liquid storage container; 2. Pipeline 1; 3. Peristaltic pump; 4. Pipeline 2; 5. Base; 6. Permeable stone; 7. Heating component; 8. Stop valve; 9. Model box; 10. Sampling interface; 11. Porous support plate; 12. Square collection tray; 13. Pipeline 3; 14. Measuring vessel; 15. Pipeline 4. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Example 1

[0036] Reference Figure 1-2 The three-dimensional soil column leaching system with temperature control and stratified sampling functions provided by the present invention mainly includes a simulated rainfall leaching unit, an assemblable soil column module, a temperature control unit and an exudate collection unit.

[0037] The simulated rainfall leaching unit is used to simulate the rainfall process and includes a liquid storage container 1, a peristaltic pump 3, and a water distributor. The outlet of the liquid storage container 1 is connected to the inlet of the peristaltic pump 3 through pipe 1 2, and the outlet of the peristaltic pump 3 is connected to the water distributor through pipe 2 4. The peristaltic pump 3 is used to precisely control the delivery flow rate of the leaching liquid, while the water distributor ensures that the leaching liquid can be sprayed evenly on the surface of the soil column.

[0038] The assemblable soil column module is the core of the system, used to fill soil samples and simulate soil profiles. It includes a base 5, a model box 9, a porous support plate 11, and a square collection tray 12. The model box 9 is set on the base 5 and is a hollow cuboid with openings at the top and bottom. In this embodiment, the specific dimensions are 30cm in length, 20cm in width, 25cm in height, and 1cm in wall thickness. The porous support plate 11 is placed at the bottom of the model box 9 to support the soil and allow the exudate to pass through. Its hole diameter is preferably 2.5mm. The square collection tray 12 is located below the porous support plate 11 and is used to collect the exudate flowing out from the bottom of the soil column. The base 5 and the square collection tray 12 are detachably sealed and connected by a flange. The model box 9 and the base 5 are fitted together by a slot and reinforced by a quick locking mechanism, thus forming a modular and well-sealed overall structure.

[0039] Optionally, permeable stones 6 can be laid on top of the soil in the model box 9 to further improve the uniformity of water distribution and prevent soil erosion.

[0040] The sidewalls of the model box 9 are provided with multiple sampling interfaces 10 along the longitudinal and radial directions, which is the key to realizing three-dimensional sampling. Specifically, one set of opposite sidewalls of the model box 9 is uniformly provided with three layers of sampling interfaces 10 along the longitudinal direction, and another set of opposite sidewalls is uniformly provided with two rows of three layers of sampling interfaces 10 along the longitudinal direction. In the same row, the vertical distance between adjacent sampling interfaces 10 is 5cm, the height of the bottom interface from the base of the box is 5cm, and the horizontal distance between columns is 10cm. Each sampling interface 10 is equipped with an openable and closable stopcock valve 8 to control the opening and closing of the sampling port.

[0041] The temperature control unit is used to precisely control the test temperature inside the soil column. It includes a heating component 7 attached to the outer wall of the model box 9 and a temperature control component electrically connected to the heating component 7. The heating component 7 is preferably a heating plate, which is evenly attached to the four outer walls of the model box 9 to achieve uniform heating. The temperature control component is preferably a PID temperature controller, whose temperature sensor probe can be inserted into the soil of the model box 9 to monitor the soil temperature in real time and provide feedback to control the heating component 7, thereby achieving dynamic and precise control of the temperature inside the soil column.

[0042] The exudate collection unit is used to collect exudates from different sources, including multiple sets of measuring vessels 14. These measuring vessels 14 are connected to the system via conduits. Specifically, one set of measuring vessels 14 is connected to the outlet of the square collection tray 12 via pipe three 13 to collect bottom exudates. The other sets of measuring vessels 14 are connected to the sampling interface 10 on the side wall of the model box 9 via pipe four 15. When the stopcock valve 8 at a specific position is opened, lateral exudates from different depths and horizontal positions can be collected.

[0043] Example 2

[0044] To further illustrate the above embodiments, the present invention also provides an operating method for a three-dimensional soil column leaching system with temperature control and stratified sampling functions. The specific steps for conducting soil column leaching tests using this system are as follows:

[0045] Step 1: Assemble the soil column module. The base 5 and the model box 9 are sealed and connected by flanges and sealing rings. The base 5 and the square liquid collection tray 12 are coupled to each other by slot embedding and quick locking mechanism. The porous support plate 11 is installed at the bottom of the model box 9 to form a complete sealed leaching system. The heating component 7 is installed on the outer wall of the model box 9.

[0046] Step 2: Prepare the target solution (such as simulated acid rain or pollutant solution) according to the test requirements, inject it into the storage container 1, and use the peristaltic pump 3 to set the required leaching flow rate;

[0047] Step 3: Control the temperature inside the model box 9 to the required temperature for the test using the temperature control component. Pour the prepared contaminated soil into the model box 9 in layers, compacting it. If necessary, lay permeable stones 6 on top of the soil.

[0048] Step 4: Start leaching. The leaching liquid is evenly sprayed onto the surface of the soil column through the water distributor. During the test, by opening the stopcock valve 8 at a specific position on the side wall of the model box 9 and connecting it to the liquid guide pipe, the seepage liquid at different spatial dimensions (different depths, different radial positions) can be collected into the corresponding measuring vessel 14.

[0049] Step 5: After the leachate sampling is completed, loosen the fastening device on the side wall of the model box 9, place the model box 9 horizontally on the sampling platform, and then sample each soil layer sequentially through the preset sampling interface 10. When sampling, the sampler is used to cut soil samples radially in layers for subsequent analysis.

[0050] Example 3

[0051] The specific experimental procedure is as follows:

[0052] Step 1: Prepare a cadmium-contaminated solution with a mass concentration of 100 mg / L as the target leachate, inject it into the storage container 1, and set the leaching flow rate to 5 mL / min using the peristaltic pump 3;

[0053] Step 2: Set the test temperature to 25℃ (simulating normal temperature environment) using a PID temperature controller. After the temperature inside the model box 9 stabilizes, pour the prepared contaminated soil into the model box 9 in layers, compacting each layer to a thickness of 5cm. Lay a total of 4 layers with a total thickness of 20cm. Then lay permeable stones 6 on top of the contaminated soil.

[0054] Step 3: Start the leaching process. The leaching liquid is evenly sprayed onto the surface of the permeable stone 6 through the water distributor, and then penetrates into the contaminated soil layer below.

[0055] Step 4: During the experiment, at 1h, 3h, 6h, 12h and 24h of leaching, the stopcock valves 8 at different positions were opened, and the exudate at different depths and radial positions was collected through pipe 4 15 into the corresponding measuring vessels 14; at the same time, the exudate in the bottom square collection tray 12 was collected through pipe 3 13.

[0056] Step 5: After the leaching test lasts for 48 hours, stop the peristaltic pump 3, close all stopcock valves 8, and take soil samples according to Step 5 of the operation method in Example 2. Use a sampler to cut soil samples radially in layers through each sampling interface 10. Take 3 parallel samples from each sampling point for subsequent pollutant content detection and analysis.

[0057] Post-test processing:

[0058] 1. Collect the leachate sample from measuring vessel 14 and test indicators such as pH and contaminant concentration;

[0059] 2. After the collected soil samples are air-dried, ground, and sieved, the residual amount and distribution of pollutants in the soil are tested.

[0060] 3. Disassemble the test device, clean and dry each component, and store it properly for future use.

[0061] Through the above embodiments, soil and leachate samples at different temperatures, time periods, and spatial locations can be accurately obtained, and the migration patterns of pollutants can be systematically analyzed, providing technical support for the remediation of contaminated soil.

[0062] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A three-dimensional soil column leaching system with temperature control and layered sampling function, characterized in that: The simulation rainfall leaching unit comprises a liquid storage container (1) for storing leaching liquid, a peristaltic pump (3) for accurately pumping liquid, and a water distributor for uniformly spraying the leaching liquid on the surface of the soil column. The soil column module comprises a base (5), a model box (9) arranged on the base (5), a porous support plate (11) arranged at the bottom of the model box (9), and a square collection tray (12) arranged below the porous support plate (11). The side walls of the model box (9) are longitudinally and radially arranged with multiple groups of sampling interfaces (10) for sampling. The temperature control unit comprises a heating assembly (7) attached to the outer wall of the model box (9), and a temperature control assembly electrically connected to the heating assembly (7) for accurately controlling the temperature. The leachate collection unit comprises multiple groups of measuring vessels (14) for collecting liquid. The measuring vessels (14) are connected to the outlet of the square collection tray (12) through a conduit, or connected to the sampling interfaces (10) on the side wall of the model box (9). The simulation rainfall leaching unit further comprises a pipe (2) and a pipe (4). The outlet of the liquid storage container (1) is connected to the water inlet of the peristaltic pump (3) through the pipe (2), and the water outlet of the peristaltic pump (3) is connected to the water distributor through the pipe (4).

2. The three-dimensional soil column leaching system with temperature control and layered sampling function according to claim 1, characterized in that: The leachate collection unit further comprises a pipe (13) and a pipe (15). The measuring vessels (14) are arranged in multiple groups. One group is connected to the water outlet of the square collection tray (12) through the pipe (13), and the other groups are connected to the sampling interfaces (10) through the pipe (15).

3. The three-dimensional soil column leaching system with temperature control and layered sampling function according to claim 1, characterized in that: Each sampling interface (10) is provided with a rotatable stop valve (8) that can be opened and closed.

4. The three-dimensional soil column leaching system with temperature control and layered sampling function according to claim 3, characterized in that: The model box (9) is a hollow rectangular box with an upper and lower opening, with a length of 30 cm, a width of 20 cm, a height of 25 cm, and a wall thickness of 1 cm. One group of opposite side walls of the model box (9) is uniformly arranged with three layers of sampling interfaces (10) in the longitudinal direction, and the other group of opposite side walls is uniformly arranged with two rows of three layers of sampling interfaces (10) in the longitudinal direction. In the same row, the vertical spacing between adjacent sampling interfaces (10) is 5 cm, the height of the lowermost interface from the bottom of the box is 5 cm, and the horizontal spacing between rows is 10 cm.

5. The three-dimensional soil column leaching system with temperature control and layered sampling function according to claim 1, characterized in that: The porous support plate (11) has a hole diameter of 2.5 mm.

6. The three-dimensional soil column leaching system with temperature control and layered sampling function according to claim 1, characterized in that: The soil column module further comprises a water-permeable stone (6) arranged above the soil body in the model box (9).

7. The three-dimensional soil column leaching system with temperature control and layered sampling function according to claim 1, characterized in that: The base (5) and the square collection tray (12) are detachably connected by flanges, the model box (9) and the base (5) are fitted by a clamping groove, and a quick locking mechanism is used for reinforcement.

8. The three-dimensional soil column leaching system with temperature control and layered sampling function according to claim 1, characterized in that: The heating assembly (7) is a heating plate uniformly attached to the four outer walls of the model box (9), and the temperature control assembly is a PID temperature controller with a temperature sensor probe that can be inserted into the soil body of the model box (9).

9. The three-dimensional soil column leaching system with temperature control and layered sampling function according to claim 1, characterized in that: The method comprises the following steps:

10. The operating method of the three-dimensional soil column leaching system with temperature control and layered sampling function, characterized in that: ​ Step one: Assemble the soil column module, the base (5) and the model box (9) are connected by flange and sealing ring, the base (5) and the square collector (12) are coupled by card slot and quick locking mechanism, the porous support plate (11) is installed at the bottom of the model box (9), forming a complete sealed leaching system, and the heating assembly (7) is installed on the outer wall of the model box (9); Step two: Configure the target solution according to the test requirements, inject it into the storage container (1), and set the required leaching liquid flow rate using the peristaltic pump (3); Step three: Control the temperature in the simulation box (9) to the required temperature for the test, pour the prepared contaminated soil into the model box (9) in layers, and lay the water permeable stone (6) on top of the contaminated soil; Step four: Start leaching, the leaching liquid is evenly sprayed on the surface of the contaminated soil through the water distributor, during the test, open the stopcock (8) at a specific position on the side wall of the model box (9) and connect the liquid guide pipe to collect the leachate at different space-time dimensions into the corresponding measuring vessel (14); Step five: After the test is completed and the leachate sampling is finished, first loosen the fastening device on the side wall of the model box (9), place the model box (9) horizontally on the sampling platform; then sample each soil layer through the pre-set sampling interface (10), and use the sampler to take soil samples in layers along the radial direction.

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