Soil and sediment micro-plastic circulating flotation device

Abstract

The utility model belongs to the field of pretreatment research of environmental pollutants, and particularly relates to a soil and sediment micro-plastic circulating flotation device which particularly comprises a batch pretreatment system and a full-automatic double-vacuum circulating flotation system. The batch pretreatment system comprises a multi-head magnetic stirrer, a matched magnetic stirrer, a magnetic stirrer controller and a plurality of sets of upper nozzle suction flasks; the full-automatic double-vacuum circulation type flotation system comprises a programming type power supply control unit, a double-vacuum suction filtration unit, a flotation liquid circulation unit and a lifting table unit. The micro-plastic circulating flotation system effectively solves the problem that in the flotation process of the micro-plastic circulating flotation system, the flow speed of the circulating pump needs to be adjusted according to the pressure of the suction filtration pump, and then the process of suction filtration and circulation can be achieved at the same time. Vacuum filtration of micro-plastic can be achieved under the condition that no vacuum filtration pump is additionally arranged, the flow speed of a water pump does not need to be manually adjusted, and flotation liquid cannot overflow; and suction filtration circulation without manual guarding can be realized, and manpower and material resources are saved.

Description

Technical Field

[0001] The utility model belongs to the field of pre-treatment research of environmental pollutants, and specifically relates to a soil and sediment microplastic circulation flotation device, in particular to the separation and flotation of microplastic particles in environmental soil and sediment samples. Background Art

[0002] Plastic pollution has become a global environmental problem, and "microplastic" pollution with a particle size of less than 5mm has become a new global environmental disaster that has attracted much attention. Microplastics can not only poison the soil environment by releasing their own toxic chemicals, but also, due to their large surface area, they can accumulate heavy metals, persistent organic pollutants, and new highly toxic organic pollutants in the environment, causing persistent pollution to the environment.

[0003] Microplastic pollution and hazards in the aquatic environment have attracted the attention of the scientific community. In recent years, many scholars have conducted a lot of scientific research. However, there are very few studies on soil microplastic pollution, especially the lack of separation methods for microplastic particles in soil and sediment samples. Traditional methods are mainly based on the principle of density separation, using gas rise or liquid agitation to separate microplastics from samples (density flotation method). With the emergence of simple density flotation separation devices, semi-automatic separation of microplastics can be achieved, but there are still problems such as much manual intervention.

[0004] Zhang Haibo and others applied for a utility model for a continuous flow separation flotation device and method for micro-particle plastics (patent application number 201510227085.1), which realized the continuous flow flotation of solid samples. This method uses a vibrating screen as a microplastic filtration container, which makes it difficult to switch between different microplastic samples, and the flotation liquid cannot be recycled. Zhang Chengli et al. applied for a device and method for extracting microplastics from soil (CN 109682654 A). The device realizes the thermal recycling of flotation liquid by setting a separation tank, a liquid storage tank and a return liquid tank, and a liquid inlet pipe is set between the liquid storage tank and the separation tank, and a liquid outlet pipe is set between the return liquid tank and the liquid storage tank, which greatly reduces the cost of microplastic screening. However, the flotation liquid passes through the filter membrane by gravity, which takes a long time; Chen Yajun et al. applied for a device and method for continuous separation and enrichment of microplastics (CN 108177273 A). By setting an air pump, an aeration branch pipe, a separator, a screen, a connector, an inlet branch pipe, an overflow branch pipe and a storage, the flotation liquid is recycled. However, there is also the problem of long time consumption and need for human supervision; He Defu et al. applied for a device and method for separating soil microplastics based on sodium bromide solution circulation (CN 109877150 A) In terms of flotation fluid, cheaper sodium bromide is used as the flotation fluid. The flotation fluid is recycled by setting up a separation unit, a vacuum filtration unit and a solution recovery unit. The use of vacuum filtration in the microplastic filtration membrane stage greatly accelerates the filtration speed. However, in the process of filtering and circulating, it is necessary to adjust the flow rate of the circulation pump according to the pressure of the filtration pump. The manpower investment is relatively large, and it is impossible to separate large quantities of soil microplastics in the short term. Utility Model Content

[0005] In order to overcome the defects in the above-mentioned existing technologies and solve the problem that the flow rate of the circulation pump needs to be manually adjusted during the process of suction and circulation, the utility model proposes a soil and sediment microplastic circulation flotation device. It aims to solve the problems of long time and human resource occupation in the separation process of large quantities of soil microplastics. The utility model is designed based on the principle of density separation, and the microplastics include but are not limited to one or more microplastics such as polyamide (PA), polypropylene (PP), polyethylene (PE), polyvinyl chloride (PVC), polypropylene (PP), polystyrene (PS), etc. To achieve the above purpose, the utility model adopts the following technical solutions:

[0006] A soil and sediment microplastic circulation flotation device comprises a batch pretreatment system and a fully automatic double vacuum circulation flotation system; the batch pretreatment system comprises a multi-head magnetic stirrer, a matching magnetic stirrer and a magnetic stirrer controller and multiple sets of upper nozzle suction bottles; the fully automatic double vacuum circulation flotation system comprises a programmable power control unit, a double vacuum filtration unit, a flotation liquid circulation unit and a lifting platform unit.

[0007] Further, the programmable power control unit includes: an aeration pump controller, a circulating water pump controller, a vacuum filtration pump controller, a circulating liquid valve controller and a vacuum filtration valve controller;

[0008] The double vacuum filtration unit is composed of a circulating water pump vacuum filtration unit and a vacuum pump vacuum filtration unit. The circulating water pump vacuum filtration unit includes an aeration pump, an aeration stone, an upper and lower nozzle filtration bottle, an adjustable circulating water pump, a circulating liquid valve and a Buchner funnel with a rubber stopper. The vacuum pump vacuum filtration unit includes an upper and lower nozzle filtration bottle, a vacuum filtration pump, a Buchner funnel with a rubber stopper and a vacuum filtration valve.

[0009] The flotation liquid circulation unit comprises: an upper suction filter bottle, an upper suction filter bottle plug, an adjustable circulating water pump circulation liquid valve and upper and lower suction filter bottles; the lifting platform unit comprises: a lifting platform; the upper suction filter bottle is placed on the lifting platform, the aeration pump is connected to the aeration stone through a pipeline, and the aeration stone passes through the upper suction filter bottle plug and is suspended in the liquid of the upper suction filter bottle;

[0010] The water inlet end of the adjustable circulating water pump is connected to the lower mouth of the upper and lower mouth suction filter bottles through a pipeline, and the water outlet end passes through the upper mouth suction filter bottle plug through a pipeline and enters the upper mouth suction filter bottle, suspended above the highest liquid level, and a vacuum suction filter valve is arranged between the adjustable circulating water pump and the upper and lower mouth suction filter bottles.

[0011] The vacuum filtration pump is connected to the upper mouth of the upper and lower mouth filtration bottle, the vacuum filtration pump and the upper and lower mouth filtration bottle are provided with a vacuum filtration valve, and the Buchner funnel with a rubber stopper is installed at the bottle mouth of the upper and lower mouth filtration bottle.

[0012] Furthermore, the controller is an electronic programmable timer with more than 10 groups of on-off period settings; the vacuum filtration pump is 0-80kPa adjustable vacuum, the aeration pump is adjustable, and the maximum aeration volume is 4L / MIN; the adjustable circulating water pump is flow adjustable, and the flow range is 500-2000L / H.

[0013] Furthermore, the lifting height of the lifting platform is more than 5 cm higher than the bottom of the upper and lower nozzle suction filtration bottles.

[0014] Furthermore, the upper-mouth suction filtration bottle and the upper-lower-mouth suction filtration bottle are triangular suction filtration bottles with a wide bottom and a narrow top, and have the same capacity of 1-5L; the diameter of the upper and lower mouths is greater than 0.5 cm.

[0015] Furthermore, filter papers with different pore sizes are arranged in the Buchner funnel, and the pore size of the filter paper is 0.45 μm-0.5 mm.

[0016] The method of using the utility model is as follows:

[0017] First, add the soil and sediment samples into the upper filter bottle of the batch pretreatment system, and add a magnetic stirrer into the filter bottle. After adding the flotation liquid to a certain height, start magnetic stirring, stir evenly and let it stand for a while;

[0018] The stirred and static microplastic samples are placed on the lifting platform together with the upper filter bottle and connected to the fully automatic circulating flotation system;

[0019] Set different power switch sequences and their switch times in the programmable power control unit, turn on the programmable power control unit, control the double vacuum filtration unit, and the flotation liquid in the upper filter bottle flows into the Büchner funnel. Under the action of the filtration unit, the flotation liquid in the Büchner funnel enters the upper and lower filter bottles, the flotation liquid is recycled, and the microplastics are filtered and left on the filter paper, completing the microplastic flotation process;

[0020] Remove the filter paper in the Büchner funnel, replace it with a new filter paper, replace a new microplastic sample, and restart the fully automatic double vacuum circulation flotation system to carry out fully automatic flotation of the next sample.

[0021] The utility model sets the flotation liquid level in the two suction bottles as high as possible, and the distance between the flotation liquid level in the upper suction bottle and the bottom of the upper mouth is smaller than the height between the flotation liquid level in the upper and lower suction bottles and the bottom of the upper mouth, so that the circulating water pump draws away part of the flotation liquid to seal the Büchner funnel, so as to form a really fast vacuum filtration system. It effectively solves the problem that the microplastic circulating flotation system needs to adjust the flow rate of the circulating pump according to the pressure of the suction pump during the flotation process in order to realize the process of filtering and circulating at the same time. The utility model forms a vacuum filtration system through the circulating water pump itself, and through the joint action of the circulating water pump, the flotation liquid and the Büchner funnel, there is no need to manually adjust the flow rate of the circulating pump, and the function of adjusting the flow rate of the water pump is realized in linkage.

[0022] Beneficial effects of the utility model:

[0023] (1) It can realize vacuum filtration of microplastics without an external vacuum filtration pump. During the filtration process, there is no need to manually adjust the flow rate of the water pump according to the filtration pressure. The flotation liquid in the Büchner funnel will not overflow. The process of filtration and circulation without manual supervision can be realized. No manual supervision and adjustment are required during the filtration process, saving manpower and material resources. (2) The upper mouth filtration bottle is plugged with a bottle stopper, and the circulating flotation liquid enters the upper mouth filtration bottle. When the aeration pump is turned on, the upper mouth filtration bottle can be actively pressurized to accelerate the flow of microplastics from the upper mouth of the upper mouth filtration bottle to the Büchner funnel for filtration. (3) In addition to the vacuum unit formed by the water pump circulation, in order to speed up the filtration speed, a vacuum pump filtration unit is also provided. When necessary, the dual vacuum filtration units can be turned on at the same time or part of the time to speed up the separation of microplastics. (4) By programming the controller of the fully automatic circulating flotation system, different programming settings can be made according to the conditions of microplastics in soil and sediments to achieve flotation without manual supervision, greatly reducing the workload and improving the flotation efficiency. (5) Microplastics can be filtered by placing qualitative filter paper in a Büchner funnel. Filter papers with different pore sizes can be placed for microplastics with different particle sizes to achieve classified flotation of microplastics with different particle sizes, which is low-cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic diagram of the batch pre-processing system of the utility model;

[0025] Figure 2 Schematic diagram of the fully automatic circulating flotation system of the utility model.

[0026] Reference numerals:

[0027] 1-circulating water pump controller, 2-magnetic stirrer controller, 3-vacuum filtration pump controller, 4-aeration pump controller, 5-lifting platform, 6-aeration pump, 7-magnetic stirrer, 8-aeration stone, 9-magnetic stirring bar, 10-upper and lower nozzle filtration bottle, 11-vacuum filtration pump, 12-Buchner funnel with rubber stopper, 13-adjustable circulating water pump, 14-circulating liquid valve, 15-vacuum filtration valve, 16-upper nozzle filtration bottle, 17-upper nozzle filtration bottle stopper, 18-circulating liquid valve controller, 19-vacuum filtration valve controller. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0029] like Figure 1-2 As shown, the utility model structural schematic diagram

[0030] A soil and sediment microplastic circulation flotation device comprises a batch pretreatment system and a fully automatic double vacuum circulation flotation system; the batch pretreatment system comprises a multi-head magnetic stirrer 7, a matching magnetic stirrer 9 and a magnetic stirrer controller 2 and a plurality of sets of upper nozzle suction bottles 16; the fully automatic double vacuum circulation flotation system comprises a programmable power control unit, a double vacuum filtration unit, a flotation liquid circulation unit and a lifting platform unit.

[0031] The programmable power control unit includes: an aeration pump controller 4, a circulating water pump controller 1, a vacuum filtration pump controller 3, a circulating liquid valve controller 18 and a vacuum filtration valve controller 19; the double vacuum filtration unit consists of a circulating water pump vacuum filtration unit and a vacuum pump vacuum filtration unit: the circulating water pump vacuum filtration unit includes an aeration pump 6, an aeration stone 8, an upper and lower nozzle filtration bottle 10, an adjustable circulating water pump 13, a circulating liquid valve 14 and a Buchner funnel with a rubber stopper 12; the vacuum pump vacuum filtration unit includes an upper and lower nozzle filtration bottle 10, a vacuum filtration pump 11, a Buchner funnel with a rubber stopper 12 and a vacuum filtration valve 15; the flotation liquid circulation unit includes: An upper filter bottle 16, an upper filter bottle plug 17, an adjustable circulating water pump 13, a circulating liquid valve 14 and upper and lower filter bottles 10; the lifting platform unit includes: a lifting platform 5; the upper filter bottle 16 is placed on the lifting platform 5, the aeration pump 6 is connected to the aeration stone 8 through a pipeline, and the aeration stone 8 passes through the upper filter bottle plug 17 and is suspended in the liquid of the upper filter bottle 16; the water inlet end of the adjustable circulating water pump 13 is connected to the lower mouth of the upper and lower filter bottles 10 through a pipeline, and the water outlet end passes through the upper filter bottle plug 17 through a pipeline to enter the upper filter bottle 16 and is suspended above the highest liquid surface, and a vacuum filter valve 15 is arranged between the adjustable circulating water pump 13 and the upper and lower filter bottles. The vacuum filtration pump 11 is connected to the upper mouth of the upper and lower mouth filtration bottle 10, and a vacuum filtration valve 15 is provided between the vacuum filtration pump 11 and the upper and lower mouth filtration bottle 10, and a Buchner funnel 12 with a rubber stopper is installed at the bottle mouth of the upper and lower mouth filtration bottle 10. Example 1

[0032] Simulation verification

[0033] Rapid qualitative filter paper is used to verify the flotation efficiency of polyethylene (PE), polyvinyl chloride (PVC), and polypropylene (PP) microplastics. The specific process is as follows:

[0034] ① Select 50 purchased microplastic particles (particle size of about 1 to 3 mm), dye them with Nile red, and add them to 4 upper-mouth suction filtration bottles 16 respectively. At the same time, add a magnetic stirring bar 9 to the bottle.

[0035] ②Prepare 6L of saturated potassium formate flotation solution.

[0036] ③ Pour saturated potassium formate solution into the upper-mouth suction bottle 16 and the upper-lower-mouth suction bottle 10. The liquid level of the upper-mouth suction bottle is 1 cm lower than the lowest point of the upper mouth, and the liquid level of the lower-mouth suction bottle is 2 cm lower than the lowest point of the upper mouth.

[0037] ④ Add 4 upper-mouth suction filtration bottles 16 to the magnetic stirrer 7 for stirring, and then let it stand for 12 hours. Connect the upper and lower suction filtration bottles to the fully automatic double vacuum filtration system.

[0038] ⑤ Connect the sample after standing together with the upper filter bottle 16 to the fully automatic double vacuum filtration system.

[0039] ⑥ Place a quick qualitative filter paper (pore size 80-120 μm) in the Buchner funnel (with a rubber stopper) 12, and set the filtration program to enable only the circulating water pump vacuum filtration system for the first 20 minutes and the double vacuum filtration unit for the next 10 minutes.

[0040] ⑦ After the program ends and filtration is completed, replace the filter paper and replace the new microplastic sample after standing. Set the filtration program to 30 minutes, and start the double vacuum filtration system at the same time to filter again.

[0041] ⑧ After completing the above steps, set the filtration program again to single vacuum filtration for 20 minutes, double vacuum filtration for 10 minutes, and double vacuum filtration for 30 minutes throughout the process.

[0042] ⑨Completed the flotation separation of 4 microplastic samples.

[0043] ⑩Repeat steps ①-⑩ three times for three different microplastics.

[0044] ⑪Count the number of microplastics on the filter membrane and calculate the microplastic recovery rate.

[0045] The above experimental process was carried out on three types of microplastics respectively. The results showed that the recovery rate of polyethylene (PE), polyvinyl chloride (PVC), and polypropylene (PP) microplastics was above 96% regardless of the filtration procedure. Example 2

[0046] Rapid qualitative filter paper was used to verify the flotation efficiency of polyethylene (PE), polyvinyl chloride (PVC), and polypropylene (PP) microplastics.

[0047] The specific implementation steps are the same as those in Example 1. The difference is that the flotation solution in Example 2 is a saturated zinc chloride solution.

[0048] The three types of microplastics were automatically floated by the device and method of the utility model. The results showed that the recovery rates of polypropylene (PP), polyethylene (PE), polyvinyl chloride (PVC), and polypropylene (PP) microplastics were between 96% and 100% regardless of the filtration procedure. Example 3

[0049] Similar to Example 2, the difference is that the purchased microplastics are first crushed in a medium-speed crusher for 4 minutes. After crushing, about 2 grams of microplastic particles are weighed and added to the flotation system. The filter membrane is a medium-speed qualitative filter paper (pore size 30 to 50 microns). The recovery rate of microplastics after flotation filtration is calculated by weight.

[0050] The three types of microplastics were automatically floated by the device and method of the utility model. The results showed that the recovery rates of polypropylene (PP), polyethylene (PE), polyvinyl chloride (PVC), and polypropylene (PP) microplastics were all above 95.5% regardless of the filtration procedure. Example 4

[0051] The simulated soil microplastic verification takes the detection of the separation efficiency of polyethylene (PE), polyvinyl chloride (PVC), and polypropylene (PP) microplastics in soil as an example. Specific process:

[0052] First, a 6 kg soil sample (from the suburbs of Nanchang City) was dried at 50°C, 60 g of soil was weighed and added to an upper-mouthed suction filtration bottle 16. A total of 30 upper-mouthed suction filtration bottles were set up, 10 of which were filled with polyethylene (PE), 10 with polyvinyl chloride (PVC), and 10 with polypropylene (PP) microplastics. At the same time, a magnetic stirrer 9 was added to the bottle.

[0053] The other steps are the same as those in Example 2.

[0054] The above experimental process was carried out on three types of microplastics respectively. The results showed that the recovery rates of polypropylene (PP), polyethylene (PE), polyvinyl chloride (PVC), and polypropylene (PP) microplastics were as follows: the average recovery rate of double vacuum filtration for 30 minutes was 96.8%, and the average recovery rate of single vacuum filtration for the first 20 minutes and double vacuum filtration for the last 10 minutes was 95.1%. Example 5

[0055] The simulated soil microplastic verification takes the separation efficiency of crushed polyethylene (PE), polyvinyl chloride (PVC), and polypropylene (PP) microplastics in soil as an example. Specific process:

[0056] The specific implementation steps are the same as those in Example 4, except that the purchased microplastics are first crushed in a medium-speed crusher for 4 minutes. After crushing, about 2 grams of microplastic particles are weighed and added to the flotation system. The recovery rate of microplastics after flotation filtration is calculated by weight.

[0057] The above experimental process was carried out on three types of microplastics respectively. The results showed that the recovery rate of polypropylene (PP), polyethylene (PE), polyvinyl chloride (PVC), and polypropylene (PP) microplastics was 95.8% after 30 minutes of double vacuum filtration, and the average recovery rate of single vacuum filtration for the first 20 minutes and double vacuum filtration for the last 10 minutes was 94.1%. Example 6

[0058] A specific example of actual separation of microplastics from a sediment

[0059] ① First, the wetland sediment samples after water withdrawal (from a lakeshore area of ​​Poyang Lake) were dried at 50°C, and a total of 1000g of soil was weighed and added to 10 upper-mouth suction filtration bottles 16 respectively, and a magnetic stirring bar 9 was added to the bottle.

[0060] ②Prepare 13L saturated zinc chloride flotation solution.

[0061] ③ Pour saturated zinc chloride solution into the upper nozzle filter bottle 16 and the upper and lower nozzle filter bottles 10, and the liquid level is 2 cm lower than the lowest point of the upper nozzle.

[0062] ④ Add 10 upper nozzle suction filtration bottles 16 to the magnetic stirrer 7 for stirring, and then let it stand for 12 hours. Connect the upper and lower nozzle suction filtration bottles to the fully automatic double vacuum filtration system.

[0063] ⑤ Connect the sample after standing together with the upper filter bottle 16 to the fully automatic double vacuum filtration system.

[0064] ⑥ Place medium-speed qualitative filter paper (pore size 30-50 μm) in the Buchner funnel (with rubber stopper) 12, and set the filtration program to a double vacuum filtration system for a full 30-minute process.

[0065] ⑦ After the program is finished and the filtration is completed, replace the filter paper and replace the new microplastic sample after standing. Repeat

[0066] ⑧Complete the flotation separation of a microplastic sample.

[0067] ⑨Repeat steps ⑤-⑦ nine times

[0068] ⑩Count the number of microplastics on the filter membrane.

[0069] After the sediment sample was flotated, 56 microplastics were obtained.

[0070] The above describes in detail the preferred implementation of this patent, but this patent is not limited to the above implementation. Various changes can be made within the knowledge scope of ordinary technicians in this field without departing from the purpose of this patent.

Claims

1. A soil and sediment microplastics circulation flotation device, characterized in that: It comprises a batch pre-treatment system and a fully automatic double vacuum circulation flotation system; the batch pre-treatment system comprises a multi-head magnetic stirrer (7), a matching magnetic stirrer (9) and a magnetic stirrer controller (2) and a plurality of sets of upper nozzle suction bottles (16); the fully automatic double vacuum circulation flotation system comprises a programmable power control unit, a double vacuum suction filtration unit, a flotation liquid circulation unit and a lifting platform unit; The programmable power control unit comprises: an aeration pump controller (4), a circulating water pump controller (1), a vacuum filtration pump controller (3), a circulating liquid valve controller (18) and a vacuum filtration valve controller (19); The double vacuum filtration unit is composed of two parts: a circulating water pump vacuum filtration unit and a vacuum pump vacuum filtration unit. The circulating water pump vacuum filtration unit comprises an aeration pump (6), an aeration stone (8), an upper and lower nozzle filtration bottle (10), an adjustable circulating water pump (13), a circulating liquid valve (14) and a Büchner funnel with a rubber stopper (12); the vacuum pump vacuum filtration unit comprises an upper and lower nozzle filtration bottle (10), a vacuum filtration pump (11), a Büchner funnel with a rubber stopper (12) and a vacuum filtration valve (15); The flotation liquid circulation unit comprises: an upper suction filter bottle (16), an upper suction filter bottle plug (17), an adjustable circulating water pump (13), a circulating liquid valve (14), and upper and lower suction filter bottles (10); the lifting platform unit comprises: a lifting platform (5); the upper suction filter bottle (16) is placed on the lifting platform (5), the aeration pump (6) is connected to the aeration stone (8) through a pipeline, and the aeration stone (8) passes through the upper suction filter bottle plug (17) and is suspended in the liquid of the upper suction filter bottle (16); The water inlet end of the adjustable circulating water pump (13) is connected to the lower nozzle of the upper and lower nozzle suction filter bottle (10) through a pipeline, and the water outlet end passes through the upper nozzle suction filter bottle plug (17) through a pipeline and enters the upper nozzle suction filter bottle (16) and is suspended above the highest liquid surface. A vacuum suction filter valve (15) is provided between the adjustable circulating water pump (13) and the upper and lower nozzle suction filter bottles; The vacuum filtration pump (11) is connected to the upper mouth of the upper and lower mouth filtration bottle (10), a vacuum filtration valve (15) is provided between the vacuum filtration pump (11) and the upper and lower mouth filtration bottle (10), and a Buchner funnel (12) with a rubber stopper is installed at the bottle mouth of the upper and lower mouth filtration bottle (10).

2. A soil and sediment microplastic circulation flotation device according to claim 1, characterized in that: The controller is an electronic programmable timer with more than 10 groups of on / off time settings; the vacuum filtration pump (11) is 0-80kPa adjustable vacuum, the aeration pump (6) is adjustable, and the maximum aeration volume is 4L / MIN; the adjustable circulating water pump (13) is flow adjustable, and the flow range is 500-2000L / H.

3. A soil and sediment microplastic circulation flotation device according to claim 1, characterized in that: The lifting height of the lifting platform is more than 5 cm higher than the bottom of the upper and lower nozzle suction bottles.

4. A soil and sediment microplastic circulation flotation device according to claim 1, characterized in that: The upper-mouth suction filter bottle and the upper-lower-mouth suction filter bottle are triangular suction filter bottles with a wide bottom and a narrow top, and have the same capacity of 1-5L; the diameters of the upper and lower mouths are greater than 0.5 cm.

5. The soil and sediment microplastic circulation flotation device according to claim 1, characterized in that: The Buchner funnel is provided with filter papers with different pore sizes, and the pore size of the filter papers ranges from 0.45 μm to 0.5 mm.

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