Device and method for efficiently degrading micro-plastics in soil

Abstract

The invention discloses a device and method for efficiently degrading soil micro-plastics, and belongs to the technical field of soil remediation. The input end of the physical-chemical cooperation mechanism is connected with the output end of the pretreatment mechanism through a spiral conveyor, and the physical-chemical cooperation mechanism is used for assisting the soil micro-plastics in biodegradation; the input end of the biological enhanced degradation mechanism is connected with the output end of the physical-chemical synergistic mechanism, and the biological enhanced degradation mechanism decomposes micro-plastics in the soil by efficiently degrading microbial florae or enzymes secreted by the microbial florae. Compared with traditional pretreatment, the method has the advantages that an ideal reaction interface is provided for biodegradation and physical-chemical synergistic effect; mild treatment conditions are adopted in the whole process, and damage of high temperature and high pressure to soil physicochemical properties is avoided; the biological stimulant and the catalyst can be naturally degraded or recycled, so that the risk of secondary pollution is avoided, and in-situ preservation and rapid recovery of soil functions are realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of soil remediation, and specifically relates to a device and method for efficiently degrading soil microplastics. Background Art

[0002] With the development of industry, intensive agricultural cultivation, and accelerated urbanization, soil pollution is becoming increasingly serious, with the combined effects of microplastics and organic pollutants being particularly prominent. Traditional soil remediation technologies have numerous limitations: physical screening methods struggle to handle tiny particulate pollutants and can easily damage soil structure; chemical leaching techniques can introduce secondary contamination and irreversibly damage soil microbial communities; and single biodegradation techniques are limited by low pollutant bioavailability and insufficient microbial activity, resulting in long remediation cycles and low efficiency.

[0003] Most existing combined remediation technologies have the defect of insufficient synergy. For example, there is a lack of differentiated treatment solutions for different types of microplastics (such as polyethylene, polyvinyl chloride, polyester, etc.) and complex soil matrices (such as clay, sand, and high-organic soil), resulting in poor stability of the remediation effect and limited scope of application. Summary of the Invention

[0004] In order to solve the above problems, the present invention adopts the following technical solutions:

[0005] A device for efficiently degrading soil microplastics, comprising

[0006] Pretreatment mechanism for screening, crushing and homogenizing the soil;

[0007] A physical-chemical synergistic mechanism, wherein the input end of the physical-chemical synergistic mechanism is connected to the output end of the pretreatment mechanism via a screw conveyor, and the physical-chemical synergistic mechanism is used to assist in the biodegradation of soil microplastics;

[0008] A bio-enhanced degradation mechanism, wherein the input end of the bio-enhanced degradation mechanism is connected to the output end of the physical-chemical synergistic mechanism, and the bio-enhanced degradation mechanism utilizes a high-efficiency degradation microbial flora or enzymes secreted by it to decompose microplastics in the soil.

[0009] Furthermore, the pre-processing mechanism includes:

[0010] A pre-processing bin, wherein the output port of the pre-processing bin is connected to the input end of the screw conveyor;

[0011] A vibrating screen is provided at the input port of the pretreatment bin and is used to screen and remove large debris from the soil;

[0012] Double crushing rollers, which are arranged in the pre-treatment bin and below the vibrating screen, and are used to crush soil clumps to increase the surface area;

[0013] A soil mixer is provided in the pretreatment bin and below the double crushing rollers to ensure uniform distribution of pollutants;

[0014] A moisture regulator is provided in the pretreatment bin and below the double crushing rollers, and is used to control soil moisture to an optimal treatment range.

[0015] Furthermore, the soil mixer comprises:

[0016] An umbrella-shaped baffle, the umbrella-shaped baffle being arranged between the double crushing rollers;

[0017] a first drive motor, the first drive motor being located at the bottom of the umbrella-shaped baffle and fixedly mounted to the umbrella-shaped baffle;

[0018] A first stirring shaft, one end of which is drivingly connected to the driving end of the first driving motor, the other end of which is located in the pretreatment chamber, and an outer surface of the first stirring shaft is provided with a first stirring blade.

[0019] Furthermore, the moisture regulator includes a high-pressure sprayer and a hot air circulator, and the high-pressure sprayer and the hot air circulator are respectively arranged on the inner wall of the pretreatment bin; the inner wall of the pretreatment bin is also provided with a humidity sensor and a pH sensor.

[0020] Furthermore, the physical-chemical synergistic mechanism includes a synergistic bin and a conveyor belt;

[0021] The input port of the cooperative bin is connected to the output end of the screw conveyor;

[0022] A conveyor belt is disposed in the cooperative warehouse body, with a first end of the conveyor belt located directly below the input port of the cooperative warehouse body and a second end located directly above the cooperative warehouse body; baffles are also provided on both sides of the conveyor belt;

[0023] A spreading plate, a catalyst dispenser and an ultraviolet lamp are sequentially arranged on the inner top wall of the cooperative bin along the transmission direction of the conveyor belt; wherein, the spreading plate is used to spread a thin layer of pretreated soil on the conveyor belt, the catalyst dispenser is used to dispense photocatalyst into the soil, and the ultraviolet lamp is used to enable the photocatalyst to generate strong oxidizing active oxygen under irradiation to degrade microplastics.

[0024] Furthermore, the lowest end of the flattening plate is 5 to 10 cm away from the top of the conveyor belt.

[0025] Furthermore, the bio-enhanced degradation mechanism includes:

[0026] a degradation chamber, the input port of which is in communication with the output port of the cooperative chamber body;

[0027] a second drive motor, the second drive motor being located outside the degradation chamber and fixedly mounted to an outer side wall of the degradation chamber;

[0028] A soil turning roller, one end of which is rotatably connected to the side wall of the degradation bin and is drivenly connected to the driving end of the second drive motor through the side wall of the degradation bin, and the other end of the soil turning roller is located in the degradation bin and is rotatably connected to the side of the degradation bin away from the second drive motor; a plurality of roller blade holders are provided on the outer surface of the soil turning roller, and the plurality of roller blade holders are equidistantly staggered and distributed in groups of two;

[0029] A nutrient solution feeder is provided on the inner top wall of the degradation bin.

[0030] Furthermore, the degradation chamber is also provided with a plurality of titanium-based IrO2 electrode plates embedded in the inner wall, which are used to apply a weak current to the soil to promote microbial electron transfer and stimulate activity.

[0031] A method for efficiently degrading soil microplastics, a method for the above-mentioned device for efficiently degrading soil microplastics, the method comprising the following steps:

[0032] S1. The soil enters the pretreatment unit, where a vibrating screen screens the contaminated soil, removing large impurities and separating coarse particles from fine soil. Remaining soil clumps after screening enter a double crushing roller for crushing. The crushed soil enters a soil mixer, where a moisture sensor and a pH sensor monitor the soil's condition in real time. Based on the monitoring data, a high-pressure sprayer and a hot air circulator operate to adjust the soil moisture content to 30%. The treated soil is then transported to the physical-chemical synergistic unit via a screw conveyor.

[0033] S2. The soil is spread on the conveyor belt by a flat plate, and the catalyst dispenser dispenses TiO2 nanocatalyst, which is irradiated under a UV lamp for 0.5 to 2 hours to generate strong oxidizing active oxygen to degrade microplastics; the soil is then transferred to the bio-enhanced degradation mechanism;

[0034] S4, the titanium-based IrO2 electrode plate is connected to a DC power supply, the bacterial agent is added through the nutrient solution doser, and the second drive motor is started to fully mix the soil and the bacterial agent to decompose the soil microplastics.

[0035] Beneficial effects:

[0036] The present invention removes large impurities and gravel from the soil through screening, crushes and breaks the soil aggregate structure, homogenizes to ensure uniform distribution of pollutants, and regulates moisture to optimize the living environment of microorganisms, significantly improving the exposure efficiency of subsequent remediation modules to pollutants. Compared with traditional pretreatment, it provides an ideal reaction interface for biodegradation and physical-chemical synergy. Mild treatment conditions are used throughout the process to avoid the damage of high temperature and high pressure to the physical and chemical properties of the soil. Both biostimulants and catalysts can be naturally degraded or recycled without the risk of secondary pollution, thereby achieving in situ preservation and rapid recovery of soil functions.

[0037] The present invention uses ultraviolet light catalytic pretreatment (TiO2 nanocatalyst) to destroy the plastic molecular chains and introduce hydroxyl groups, thereby increasing the biodegradation rate; a weak current is applied during the biodegradation process to promote the contact between pollutants and microorganisms through the electromigration effect. At the same time, the trace active oxygen generated by electrolysis can enhance the degradation effect and shorten the repair cycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 Schematic diagram of the structure of the device for efficiently degrading soil microplastics according to the present invention;

[0039] Explanation of reference numerals: 1. pretreatment mechanism; 11. vibrating screen; 12. double crushing rollers; 13. soil mixer; 14. high-pressure sprayer; 15. hot air circulator;

[0040] 2. Screw conveyor;

[0041] 3. Physical-chemical synergistic mechanism; 31. Spreading plate; 32. Catalyst dispenser; 33. UV lamp; 34. Conveyor belt; 35. Baffle;

[0042] 4. Bio-enhanced degradation mechanism; 41. Soil turning roller; 42. Roller cutter holder; 43. Titanium-based IrO2 electrode plate. DETAILED DESCRIPTION

[0043] This section will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present invention, but it should not be understood as a limitation on the scope of protection of the present invention.

[0044] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0045] In the description of the present invention, "several" means one or more, "many" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. The use of "first" and "second" in the description is solely for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0046] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, and connecting should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0047] Example 1

[0048] refer to Figure 1 , a device for efficiently degrading soil microplastics, comprising

[0049] Pretreatment mechanism 1, for screening, crushing and homogenizing the soil;

[0050] A physical-chemical synergistic mechanism 3, wherein the input end of the physical-chemical synergistic mechanism 3 is connected to the output end of the pretreatment mechanism 1 through a screw conveyor 2, and the physical-chemical synergistic mechanism 3 is used to assist in the biodegradation of soil microplastics;

[0051] The bio-enhanced degradation mechanism 4 has an input end connected to the output end of the physical-chemical synergistic mechanism 3 , and the bio-enhanced degradation mechanism 4 utilizes highly efficient degradation microbial flora or enzymes secreted by them to decompose microplastics in the soil.

[0052] Preferably, the pretreatment mechanism 1 comprises:

[0053] A pre-treatment bin, the output port of which is connected to the input end of the screw conveyor 2;

[0054] Vibrating screen 11, which is provided at the input port of the pre-treatment bin and is used to screen out large debris from the soil;

[0055] Double crushing rollers 12 are arranged in the pre-treatment bin and below the vibrating screen 11, and are used to crush soil clumps to increase the surface area;

[0056] A soil mixer 13 is provided in the pretreatment bin and below the double crushing rollers 12 to ensure uniform distribution of pollutants;

[0057] The moisture regulator is arranged in the pre-treatment bin and is located below the double crushing rollers 12, and is used to control the soil moisture to the optimal treatment range.

[0058] Preferably, the soil mixer 13 comprises:

[0059] An umbrella-shaped baffle is provided between the double crushing rollers 12;

[0060] A first drive motor is located at the bottom of the umbrella-shaped baffle and is fixedly mounted to the umbrella-shaped baffle;

[0061] A first stirring shaft, one end of which is drivingly connected to the driving end of the first driving motor, the other end of which is located in the pretreatment chamber, and an outer surface of the first stirring shaft is provided with a first stirring blade.

[0062] Preferably, the moisture regulator includes a high-pressure sprayer 14 and a hot air circulator 15, which are respectively arranged on the inner wall of the pretreatment bin; the inner wall of the pretreatment bin is also provided with a humidity sensor and a pH sensor.

[0063] Preferably, the physical-chemical synergistic mechanism 3 includes a synergistic bin and a conveyor belt 34;

[0064] The input port of the cooperative bin is connected to the output end of the screw conveyor 2;

[0065] A conveyor belt 34 is provided in the cooperative bin, with a first end of the conveyor belt 34 located directly below the input port of the cooperative bin and a second end located directly above the cooperative bin; baffles 35 are also provided on both sides of the conveyor belt 34;

[0066] A spreading plate 31, a catalyst dispenser 32 and an ultraviolet lamp 33 are sequentially arranged on the inner top wall of the cooperative bin along the transmission direction of the conveyor belt 34; wherein, the spreading plate 31 is used to spread a thin layer of pretreated soil on the conveyor belt 34, the catalyst dispenser 32 is used to dispense photocatalyst into the soil, and the ultraviolet lamp 33 is used to enable the photocatalyst to produce strong oxidizing active oxygen under irradiation to degrade microplastics.

[0067] Preferably, the lowest end of the spreading plate 31 is 5 to 10 cm away from the top of the conveyor belt.

[0068] Preferably, the bio-enhanced degradation mechanism 4 comprises:

[0069] A degradation chamber, the input port of which is connected to the output port of the cooperative chamber body;

[0070] A second drive motor is located outside the degradation chamber and is fixedly mounted to an outer wall of the degradation chamber;

[0071] A soil turning roller 41, one end of which is rotatably connected to the side wall of the degradation chamber and passes through the side wall of the degradation chamber to be driven and connected to the drive end of the second drive motor. The other end of the soil turning roller 41 is located in the degradation chamber and is rotatably connected to the side of the degradation chamber away from the second drive motor. The outer surface of the soil turning roller 41 is provided with a plurality of roller blade holders 42, and the plurality of roller blade holders 42 are equidistantly staggered and arranged in groups of two.

[0072] The nutrient solution feeder is arranged on the inner top wall of the degradation bin.

[0073] Preferably, the degradation chamber is further provided with a plurality of titanium-based IrO2 electrode plates 43 embedded in the inner wall, which are used to apply a weak current to the soil to promote microbial electron transfer and stimulate activity.

[0074] Example 2

[0075] A method for efficiently degrading soil microplastics, a method for the device for efficiently degrading soil microplastics in Example 1, comprising the following steps:

[0076] S1. The soil enters the pretreatment unit, where a vibrating screen screens the contaminated soil, removing large impurities and separating coarse particles from fine soil. Remaining soil clumps after screening enter a double crushing roller for crushing. The crushed soil enters a soil mixer, where a moisture sensor and a pH sensor monitor the soil's condition in real time. Based on the monitoring data, a high-pressure sprayer and a hot air circulator operate to adjust the soil moisture content to 30%. The treated soil is then transported to the physical-chemical synergistic unit via a screw conveyor.

[0077] S2. The soil is spread on the conveyor belt by a flat plate, and the catalyst dispenser dispenses TiO2 nanocatalyst, which is irradiated under a UV lamp for 0.5 to 2 hours to generate strong oxidizing active oxygen to degrade microplastics; the soil is then transferred to the bio-enhanced degradation mechanism;

[0078] S4, the titanium-based IrO2 electrode plate is connected to a DC power supply, the bacterial agent is added through the nutrient solution doser, and the second drive motor is started to fully mix the soil and the bacterial agent to decompose the soil microplastics.

[0079] In this embodiment, the spacing between the titanium-based IrO2 electrode plates 43 is 30 cm, and the current intensity is 0.1-0.5 mA / cm 2 .

[0080] In this embodiment, the bioreactor is a horizontal cylindrical tank made of 316 stainless steel.

[0081] In this embodiment, the wavelength of the ultraviolet lamp is 254 nm, the particle size of the TiO2 nano-catalyst powder is 20-50 nm, and the thickness of the thin layer of soil during treatment is 5-10 cm.

[0082] In this embodiment, the UV irradiation intensity is 10-20 mW / cm 2 .

[0083] The above description is merely a preferred embodiment of the present invention and does not limit the technical scope of the present invention. Therefore, any minor modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A device for efficiently degrading soil microplastics, characterized in that: include Pretreatment mechanism for screening, crushing and homogenizing the soil; A physical-chemical synergistic mechanism, wherein the input end of the physical-chemical synergistic mechanism is connected to the output end of the pretreatment mechanism via a screw conveyor, and the physical-chemical synergistic mechanism is used to assist in the biodegradation of soil microplastics; A bio-enhanced degradation mechanism, wherein the input end of the bio-enhanced degradation mechanism is connected to the output end of the physical-chemical synergistic mechanism, and the bio-enhanced degradation mechanism utilizes a high-efficiency degradation microbial flora or enzymes secreted by it to decompose microplastics in the soil.

2. The device for efficiently degrading soil microplastics according to claim 1, characterized in that: The pre-processing mechanism comprises: A pre-processing bin, wherein the output port of the pre-processing bin is connected to the input end of the screw conveyor; A vibrating screen is provided at the input port of the pretreatment bin and is used to screen and remove large debris from the soil; Double crushing rollers, which are arranged in the pre-treatment bin and below the vibrating screen, and are used to crush soil clumps to increase the surface area; A soil mixer is provided in the pretreatment bin and below the double crushing rollers to ensure uniform distribution of pollutants; A moisture regulator is provided in the pretreatment bin and below the double crushing rollers, and is used to control soil moisture to an optimal treatment range.

3. The device for efficiently degrading soil microplastics according to claim 2, characterized in that: The soil mixer comprises: An umbrella-shaped baffle, the umbrella-shaped baffle being arranged between the double crushing rollers; a first drive motor, the first drive motor being located at the bottom of the umbrella-shaped baffle and fixedly mounted to the umbrella-shaped baffle; A first stirring shaft, one end of which is drivingly connected to the driving end of the first driving motor, the other end of which is located in the pretreatment chamber, and an outer surface of the first stirring shaft is provided with a first stirring blade.

4. The device for efficiently degrading soil microplastics according to claim 2, characterized in that: The moisture regulator includes a high-pressure sprayer and a hot air circulator, which are respectively arranged on the inner side wall of the pretreatment bin; the inner side wall of the pretreatment bin is also provided with a humidity sensor and a pH sensor.

5. The device for efficiently degrading soil microplastics according to claim 1, characterized in that: The physical-chemical synergistic mechanism includes a synergistic bin and a conveyor belt; The input port of the cooperative bin is connected to the output end of the screw conveyor; A conveyor belt is disposed in the cooperative warehouse body, with a first end of the conveyor belt located directly below the input port of the cooperative warehouse body and a second end located directly above the cooperative warehouse body; baffles are also provided on both sides of the conveyor belt; A spreading plate, a catalyst dispenser and an ultraviolet lamp are sequentially arranged on the inner top wall of the cooperative bin along the transmission direction of the conveyor belt; wherein, the spreading plate is used to spread a thin layer of pretreated soil on the conveyor belt, the catalyst dispenser is used to dispense photocatalyst into the soil, and the ultraviolet lamp is used to enable the photocatalyst to generate strong oxidizing active oxygen under irradiation to degrade microplastics.

6. The device for efficiently degrading soil microplastics according to claim 5, characterized in that: The lowest end of the flattening plate is 5 to 10 cm away from the top of the conveyor belt.

7. The device for efficiently degrading soil microplastics according to claim 5, characterized in that: The bio-enhanced degradation mechanism comprises: a degradation chamber, the input port of which is in communication with the output port of the cooperative chamber body; a second drive motor, the second drive motor being located outside the degradation chamber and fixedly mounted to an outer side wall of the degradation chamber; A soil turning roller, one end of which is rotatably connected to the side wall of the degradation bin and is drivenly connected to the driving end of the second drive motor through the side wall of the degradation bin, and the other end of the soil turning roller is located in the degradation bin and is rotatably connected to the side of the degradation bin away from the second drive motor; a plurality of roller blade holders are provided on the outer surface of the soil turning roller, and the plurality of roller blade holders are equidistantly staggered and distributed in groups of two; A nutrient solution feeder is provided on the inner top wall of the degradation bin.

8. The device for efficiently degrading soil microplastics according to claim 7, characterized in that: The degradation chamber is also provided with a plurality of titanium-based IrO2 electrode plates embedded in the inner wall, which are used to apply a weak current to the soil, promote microbial electron transfer, and stimulate activity.

9. A method for efficiently degrading soil microplastics, characterized in that: A method for the device for efficiently degrading soil microplastics according to any one of claims 1 to 8, comprising the following steps: S1. The soil enters the pretreatment unit, where a vibrating screen screens the contaminated soil, removing large impurities and separating coarse particles from fine soil. Remaining soil clumps after screening enter a double crushing roller for crushing. The crushed soil enters a soil mixer, where a moisture sensor and a pH sensor monitor the soil's condition in real time. Based on the monitoring data, a high-pressure sprayer and a hot air circulator operate to adjust the soil moisture content to 30%. The treated soil is then transported to the physical-chemical synergistic unit via a screw conveyor. S2. The soil is spread on the conveyor belt by a flat plate, and the catalyst dispenser dispenses TiO2 nanocatalyst, which is irradiated under a UV lamp for 0.5 to 2 hours to generate strong oxidizing active oxygen to degrade microplastics; the soil is then transferred to the bio-enhanced degradation mechanism; S4, the titanium-based IrO2 electrode plate is connected to a DC power supply, the bacterial agent is added through the nutrient solution doser, and the second drive motor is started to fully mix the soil and the bacterial agent to decompose the soil microplastics.

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