LU503220B1

LU503220B1 - Separation device and method of microplastics in forest soil

Info

Publication number: LU503220B1
Application number: LU503220A
Authority: LU
Inventors: Yingying Liu
Original assignee: Guizhou Inst Biology
Priority date: 2022-12-20
Filing date: 2022-12-20
Publication date: 2023-06-21

Abstract

The invention discloses a separation device and a separation method of microplastics in forest soil. The device comprises a base, where a separation assembly, a filter assembly, a collection assembly and a digestion assembly are installed on the base. The method specifically comprises the following steps: Step 1: sampling; Step 2: pretreating; Step 3: flotation; Step 4: filtering; Step 5: digesting; Step 6: collecting. The separation process is simple and the operation method is convenient, and can efficiently separate microplastics from forest soil; meanwhile, microplastics is separated by the first filter membrane, the second filter membrane and the third filter membrane according to different particle sizes, and then soaked in digestion solution to digest the mixed organic substances, so as to obtain high-purity microplastics, which is convenient for in-depth research on the content and components of microplastics with different particle sizes in forest soil.

Description

DESCRIPTION LU503220

SEPARATION DEVICE AND METHOD OF MICROPLASTICS IN

FOREST SOIL

TECHNICAL FIELD

The invention relates to the technical field of solid waste disposal technology, and in particular to a separation device and a separation method of microplastics in forest soil.

BACKGROUND

Microplastics refers to plastic fibers, fragments, particles, etc. with a particle size of less than Smm. Microplastics has the characteristics of light weight, small particle size, large quantity and difficult degradation, and is widely distributed in marine, land waters and soil ecosystems.

With the use of plastic products, microplastics widely exists in all kinds of soils with different land use types in the world. microplastics pollution has become a global environmental problem and one of the research hotspots of environmental science.

Compared with microplastics in water environment, microplastics in land soil is more difficult to separate and extract. From the environmental background, the composition of land soil is complex, and there are many objective influencing factors. It is difficult to carry out relevant scientific research experiments in microplastics, and the separation and detection effects are not obvious. At present, the focus of microplastics pollution is mainly on the water environment. There is relatively little research on the present situation of land microplastics pollution, especially the microplastics pollution in forest soil.

The forest soil is rich in high-concentration organic matter due to the input of dry branches and fallen leaves, animal and plant residues in the forest ecosystem. The structure and composition of microplastics changes under the mediation of organic matter, while the organic matter embeds or mixes in the forest soil, resulting in the formation of tiny aggregates between the organic matter in the forest soil and microplastics, thus affecting the separation of microplastics. At present, there is still no efficient and accurate separation method to separate microplastics from the forest soil, which restricts people's research on microplastics pollution in the forest soil. Therefore, it is urgent to develop a separation device and a separation method of microplastics in forest soil to solve the above problems.

SUMMARY LU503220

The purpose of the present invention is to provide a separation device and a separation method of microplastics in forest soil, so as to solve the problems existing in the prior art.

In order to achieve the above purpose, the invention provides the following scheme: the invention provides a separation device of microplastics in forest soil, which comprises a base, where a separation assembly, a filter assembly, a collection assembly and a digestion assembly are installed on the base; the separation assembly is communicated with the filter assembly, the filter assembly is communicated with the collection assembly, the collection assembly is communicated with the separation assembly, the filter assembly is communicated with the digestion assembly, the collection assembly and the digestion assembly are located below the filter assembly; a suspension discharge pipe is fixedly installed between the separation assembly and the filter assembly, a first water pump is fixedly installed on the suspension discharge pipe, one end of the suspension discharge pipe extends through the separation assembly to the inside of the separation assembly and is fixedly connected with a floating ball unit, and the other end of the suspension discharge pipe extends through the side wall of the filter barrel to the inside of the separation assembly and is fixedly connected with a shunt unit, where the shunt unit comprises an upper shell, the top of the upper shell is fixedly connected and communicated with the suspension discharge pipe; the upper shell is rotationally connected with the lower shell through a second sealed bearing; a propeller is fixedly installed in the middle of the top surface of the lower shell; and a plurality of water diversion holes are formed on the top surface of the lower shell.

Preferably, the separation assembly comprises a separation barrel, the bottom of the separation barrel is fixedly equipped with an electric heater, and the bottom of the electric heater is fixedly connected with the base, and the top surface of the base is embedded with a motor, the output shaft of the motor is fixedly connected with a rotating shaft, the rotating shaft sequentially penetrates through the electric heater and the bottom wall of the separation barrel and is fixedly connected with a stirring paddle, a first sealed bearing is arranged between the rotating shaft and the bottom wall of the separation barrel, and an ultrasonic transmitter is fixedly installed on the outer side wall of the separation barrel.

Preferably, the filter assembly comprises a filter barrel, in which a first filter membrane, à,593220 second filter membrane and a third filter membrane are detachably installed from top to bottom, the suspension discharge pipe is located at the top of the first filter membrane, and a first drain pipe and a second drain pipe are fixedly installed at the bottom of the filter barrel, the first drain pipe is communicated with the collection assembly, the second drain pipe is communicated with the digestion assembly, and the first drain pipe and the second drain pipe are respectively fixedly provided with control valves.

Preferably, the aperture of the second filter membrane is smaller than that of the first filter membrane and larger than that of the third filter membrane.

Preferably, the collection assembly comprises a collection barrel, the top surface of the base is provided with a first installation groove, the collection barrel is placed in the first installation groove, the collection barrel is communicated with the separation assembly through a return pipe, and a second water pump is fixedly installed on the return pipe.

Preferably, the digestion assembly comprises a digestion solution storage barrel, the top surface of the base is provided with a second installation groove, the digestion solution storage barrel is placed in the second installation groove, the digestion solution storage barrel is communicated with the filter assembly through a digestion solution conveying pipe, and a third water pump is fixedly installed on the digestion solution conveying pipe.

A separation method of microplastics in forest soil, comprises the following specific steps:

Step 1: sampling

Collecting soil in the forest;

Step 2: pretreating

Air-drying the soil to remove gravel, plant roots and other related impurities in the soil to obtain a soil sample to be treated;

Step 3: flotation

Putting the soil sample into a separation assembly, adding flotation solution, stirring, and standing until the materials in the separation assembly are divided into an upper non-precipitation layer and a lower precipitation layer, where the non-precipitation layer contains microplastics;

Step 4: filtering LU503220

Starting the first water pump, discharging the non-precipitation layer in the separation assembly into the filter assembly, filtering the non-precipitation layer by the separation assembly, and attaching the microplastics in the separation assembly, leaving flotation solution after filtering the non-precipitation layer, flowing the flotation solution into the bottom of the separation assembly, and discharging the flotation solution into the collection assembly;

Step 5: digesting

Adding the digestion solution in the digestion assembly into the filter assembly, digesting the organic substances remaining in the filter assembly, and then discharging the digestion solution into the digestion assembly;

Step 6: collecting.

Classifying and collecting microplastics with different particle sizes in the filter assembly.

Preferably, in step 3, starting the electric heater to heat the flotation solution to 35-45 degrees.

Preferably, in step 3, starting the ultrasonic transmitter.

Preferably, in step 5, soaking the digestion solution for 10-5min, replacing it with a new digestion solution, and repeating this step for 2-3 times until the organic substances are digested.

The invention discloses the following technical effects:

In the invention, the floating ball unit is located between the non-precipitation layer on the upper layer and the precipitation layer on the lower layer, so that substances of the precipitation layer are prevented from being sucked into the suspension discharge pipe, and the purity of the non-precipitation layer is kept, the non-precipitation layer enters the shunt unit through the suspension discharge pipe, enters from the upper shell, and then flows into the lower shell; the non-precipitation layer directly impacts the propeller, causing the propeller to rotate; as the upper shell is rotationally connected with the lower shell through the second sealed bearing, the lower shell rotates with the propeller; and the non-precipitation layer flows out from the water diversion holes while the lower shell rotates. As the non-precipitation layer flows out through the water diversion unit, the non-precipitation layer is dispersed more evenly when entering the filter assembly, thus preventing the non-precipitation layer from hitting the same position and causing damage to the filter assembly. At the same time, the non-precipitation layer disperses into the filter assembly, which prevents the microplastics from depositing in the same position, causing aso blockage and affecting the filtering effect of the filter assembly, so that the filtering efficiency is effectively improved.

Because the forest soil is rich in high-concentration organic matter, and the density of organic matter is similar to that of microplastics, the microplastics filtered by ordinary separation devices is often mixed with organic matter. In the device and method of the invention, by adding a digestion assembly on the basis of soil microplastics separation, microplastics is separated by the first filter membrane, the second filter membrane and the third filter membrane according to different particle sizes, and then soaked in digestion solution, the mixed organic matter in microplastics can be digested and removed in advance, so that microplastics does not contain organic impurities, and the separated microplastics can be improved, and the accuracy of the test data is guaranteed.

The separation process is simple and the operation method is convenient; related impurities such as gravel and plant roots are removed through pretreatment, and then organic substances such as animal and plant residues in forest soil are efficiently removed through soaking in digestion solution and double removal method, so that tiny aggregates formed by organic matter and microplastics in forest soil are effectively eliminated, the technical problem that high-concentration organic matter affects the separation of microplastics in soil is solved, microplastics in forest soil is efficiently separated, and high-purity microplastics is obtained, which is convenient for in-depth study of microplastics content and composition in forest soil.

BRIEF DESCRIPTION OF THE FIGURES

In order to more clearly explain the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings that need to be used in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained according to these drawings without any creative labor.

FIG. 1 is a front view of a separation device of microplastics in forest soil;

FIG. 2 is a plan view of the separation device of microplastics in forest soil;

FIG. 3 is a structural diagram of a floating ball unit;

FIG. 4 is a structural diagram of a frame, a sealing ring and a handle; LU503220

FIG. 5 shows the adsorption state of the floating ball unit;

FIG. 6 is a structural schematic diagram of the water diversion unit;

FIG. 7 is a plan view of the lower shell; in figures: 1. base; 11. first installation groove; 12. second installation groove; 2. separation assembly; 21. separation barrel; 211. strong electromagnetic block; 22. electric heater; 23. electric heater; 231. timers; 24. rotating shaft; 25. stirring paddle; 26. first sealed bearing; 27. ultrasonic transmitter; 3. filter assembly; 31. filter barrel; 311. micro-motor; 312. propeller; 32. first filter membrane; 322. frame; 323. sealing ring; 324. handle; 33. second filter membrane; 34. third filter membrane; 35. suspension discharge pipe; 351. flexible hose; 352. floating ball; 353. iron block; 354. bottom bin; 355. gravity balls; 356. upper shell; 357. second sealed bearing; 358. lower shell; 3581. propeller; 3582. water diversion holes; 36. first drain pipe; 37. first water pump; 38. control valves; 39. second drain pipe; 4. collection assembly; 41. collection barrel; 42. return pipe; 43. second water pump; 5. digestion assembly; 51. digestion solution storage barrel; 52. digestion solution conveying pipe; 53. third water pump.

DESCRIPTION OF THE INVENTION

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, but not all of them. Based on the embodiment of the present invention, all other embodiments obtained by ordinary technicians in the field without creative labor are within the scope of the present invention.

In order to make the above objects, features and advantages of the present invention more obvious and understandable, the present invention will be explained in further detail below with reference to the drawings and detailed description.

The invention provides a separation device of microplastics in forest soil, which comprises a base 1, where the base 1 1s provided with a separation assembly 2, a filter assembly 3, a collection assembly 4 and a digestion assembly 5, the separation assembly 2 is communicated with the filter assembly 3, the filter assembly 3 is communicated with the collection assembly 4,

the collection assembly 4 is communicated with the separation assembly 2, the filter assembly 3 503220 is communicated with the digestion assembly 5, the collection assembly 4 and the digestion assembly 5 are located below the filter assembly 3; a suspension discharge pipe 35 1s fixedly installed between the separation assembly 2 and the filtration module 3, and the first water pump 37 1s fixedly installed on the suspension discharge pipe 35. One end of the suspension discharge pipe 35 extends through the separation assembly 2 to the inside of the separation assembly 2 and is fixedly connected with a floating ball unit. The other end of the suspension discharge pipe 35 extends through the side wall of the filter barrel 31 to the inside of the separation assembly 2 and is fixedly connected with a shunt unit, where the shunt unit includes an upper shell 356. The top of the upper shell 356 is fixedly connected and communicated with the suspension discharge pipe 35. The upper shell 356 is rotationally connected with the lower shell 358 through the second sealed bearing 357. A propeller 3581 is fixedly installed in the middle of the top surface of the lower shell 358, and a plurality of water diversion holes 3582 are formed in the top surface of the lower shell 358.

Putting the soil sample into a separation assembly 2, adding flotation solution, stirring, and standing until the materials in the separation assembly 2 are divided into an upper non-precipitation layer and a lower precipitation layer, where the non-precipitation layer contains microplastics; starting the first water pump 37, and discharging the non-precipitation layer in the separation assembly 2 into the filter assembly 3, filtering the non-precipitation layer by the filter assembly 3, and attaching the microplastics in the filter assembly 3, leaving flotation solution after filtering the non-precipitation layer, flowing the flotation solution into the bottom of the filter assembly 3, and discharging the flotation solution into the collection assembly 4.

Adding the digestion solution in the digestion assembly 5 into the filter assembly 3, digesting the organic substances remaining in the filter assembly 3, and then discharging the digestion solution into the digestion assembly 4; finally, classifying and collecting microplastics with different particle sizes in the filter assembly 3.

The floating ball unit is located between the non-precipitation layer on the upper layer and the precipitation layer on the lower layer, so that substances of the precipitation layer are prevented from being sucked into the suspension discharge pipe 35, and the purity of the non-precipitation layer is kept. The non-precipitation layer enters the shunt unit through the suspension discharge pipe 35, enters from the upper shell 356, and then flows into the loWEf 503220 shell 358. The non-precipitation layer directly impacts the propeller 3581, causing the propeller 3581 to rotate. As the upper shell 356 is rotationally connected with the lower shell 358 through the second sealed bearing 357, the lower shell 358 rotates with the propeller 3581, and the non-precipitation layer flows out of the water diversion holes 3582 while the lower shell 358 rotates. As the non-precipitation layer flows out through the water diversion unit, the non-precipitation layer is dispersed more evenly when entering the filter assembly 3, thus preventing the non-precipitation layer from hitting the same position and causing damage to the filter assembly 3. At the same time, the non-precipitation layer disperses into the filter assembly 3, which prevents the microplastics from depositing at the same position, causing blockage and affecting the filtering effect of the filter assembly 3, so that the filtering efficiency is effectively improved.

In a further optimization scheme, the separation assembly 2 comprises a separation barrel 21, the separation barrel 21 is a transparent glass barrel. An electric heater 22 is fixedly installed at the bottom of the separation barrel 21, and the bottom of the electric heater 22 is fixedly connected with the base 1. A motor 23 is embedded in the top surface of the base 1, and the output shaft of the motor 23 is fixedly connected with a rotating shaft 24, the rotating shaft 24 sequentially penetrates through the electric heater 22 and the bottom wall of the separation barrel 21 and is fixedly connected with a stirring paddle 25. A first sealed bearing 26 is arranged between the rotating shaft 24 and the bottom wall of the separation barrel 21, and an ultrasonic transmitter 27 is fixedly installed on the outer side wall of the separation barrel 21. When in use, the soil sample is put into the separation barrel 21, the flotation solution is added, and then the motor 23 is started. The motor 23 drives the stirring paddle 25 to rotate, and the soil sample and the flotation solution are stirred evenly. At the same time, the electric heater 22 or the ultrasonic transmitter 27 can be turned on according to the test requirements, and the electric heater 22 and the ultrasonic transmitter 27 can be turned on at the same time to accelerate the separation of the non-precipitation layer from the lower precipitation layer, and then the materials in the separation barrel 21 are left standing until the upper non-precipitation layer and the lower precipitation layer are separated. The non-precipitation layer contains microplastics. The motor 23, the electric heater 22 and the ultrasonic transmitter 27 are all equipped with timers 231,

which can set the working time of the motor 23, the electric heater 22 and the ultrasonie 593220 transmitter 27.

After the ultrasonic transmitter 27 is turned on, the ultrasonic waves pass through the transparent glass barrel, that is, the separation barrel 21, and generates ultrasonic cavitation for the mixed solution of the soil sample and flotation solution. Ultrasonic cavitation refers to the dynamic process of the growth and collapse of micro-cavitation bubbles in liquid when the sound pressure reaches a certain value. Cavitation generally includes three stages: the formation, growth and violent collapse of cavitation bubbles. When the container filled with liquid is filled with ultrasonic waves, tens of thousands of tiny bubbles, namely cavitation bubbles, are generated due to the vibration of the liquid. These bubbles grow in the negative pressure zone formed by longitudinal propagation of ultrasonic waves, and close rapidly in the positive pressure zone, thus being compressed and stretched under alternating positive and negative pressures. At the moment when the bubble is compressed until it collapses, huge instantaneous pressure will be generated, which can cause the surface of the solid suspended in the liquid to be destroyed sharply, and the soil sample will be separated into tiny particles. At the same time, the soil will be separated from the microplastics particles, and the microplastics particles will float upward with the bubble, thus accelerating the separation of the non-precipitation layer and the precipitation layer.

In a further optimization scheme, the filter assembly 3 comprises a filter barrel 31, in which a first filter membrane 32, a second filter membrane 33 and a third filter membrane 34 are detachably installed from top to bottom. The shunt unit is located at the top of the first filter membrane 32, and a first drain pipe 36 and a second drain pipe 39 are fixedly installed at the bottom of the filter barrel 31. The first drain pipe 36 is communicated with the collection assembly 4, the second drain pipe 39 is communicated with the digestion assembly 5, and the first drain pipe 36 and the second drain pipe 39 are respectively fixedly provided with control valves 38.

The first water pump 37 is started, and the non-precipitation layer in the separation barrel 21 is discharged into the filter barrel 31. The non-precipitation layer is filtered by the first filter membrane 32, the second filter membrane 33 and the third filter membrane 34, and microplastics with different particle sizes is attached to the first filter membrane 32, the second filter membrane 33 and the third filter membrane 34. After the non-precipitation layer is filtered, 503220 flotation solution remains and flows into the bottom of the separation barrel 21. The control valve 38 on the first drain pipe 36 is opened, so that the flotation solution is discharged into the collection barrel 41 through the first drain pipe 36.

In a further optimization scheme, a micro-motor 311 is fixed on the bottom side of the filter barrel 31, and the output shaft of the micro-motor 311 penetrates through the side wall of the filter barrel 31 and is fixedly connected with a propeller 312, and a sealed bearing is arranged between the output shaft of the micro-motor 311 and the side wall of the filter barrel 31. In the process of filtration and digestion, the micro-motor 311 is turned on to make the propeller 312 vibrate the liquid in the filter barrel 31, so as to avoid the blockage of the first filter membrane 32, the second filter membrane 33 and the third filter membrane 34, and at the same time speed up the filtration or digestion and improve the filtration or digestion effect.

In a further optimization scheme, the floating ball unit includes a flexible hose 351, the flexible hose 352 is fixedly connected and communicated with the suspension discharge pipe 35.

The flexible hose 351 is located inside the separation barrel 21, and a floating ball 352 is sleeved on the flexible hose 351. The liquid inlet end of the flexible hose 351 is located at the top of the floating ball 352, and the top end of the floating ball 352 is embedded with an iron block 353.

The bottom of the floating ball 352 is screwed with a bottom bin 354, and a plurality of gravity balls 355 are placed in the bottom bin 354. A strong electromagnetic block 211 is fixed on the side wall of the separation barrel 21, and the strong electromagnetic block 211 is magnetically matched with the iron block 353. Before the separation operation in the separation barrel 21, the strong electromagnetic block 211 is energized, and the floating ball 352 is adsorbed on the strong electromagnetic block 211 through the iron block 353, which will not affect the rotation of the stirring paddle 25. After the separation in the separation barrel 21 is completed, the materials in the separation barrel 21 are left standing until the upper non-precipitation layer and the lower precipitation layer are divided. After the power supply of the strong electromagnetic block 211 is turned off, the floating ball 352 falls into the upper non-precipitation layer and continues to sink until it falls to the surface of the lower precipitation layer, then the first water pump 37 can be turned on to discharge the non-precipitation layer in the separation barrel 21 into the filter barrel 31. Since the liquid inlet end of the flexible hose 351 is located at the top of the floating ball 352,

which is higher than the surface of the lower precipitation layer, the precipitation layer will NP503220 be sucked into the flexible hose 351, and the purity of the non-precipitation layer will be maintained. The number of gravity balls 355 placed in the bottom bin 354 can be selected according to the density of the selected flotation solution, so that they can sink into the non-precipitation layer.

In a further optimization scheme, the aperture of the second filter membrane 33 1s smaller than that of the first filter membrane 32 and larger than that of the third filter membrane 34. The first filter membrane 32 is 20-80 mesh, preferably 50 mesh, the second filter membrane 33 is 100-200 mesh, preferably 160 mesh, and the third filter membrane 34 is 300-500 mesh, preferably 350 mesh.

In a further optimization scheme, the filter barrel 31 is rectangular, the side of the filter barrel 31 1s provided with three placing grooves, and the outer filtering sides of the first filter membrane 32, the second filter membrane 33 and the third filter membrane 34 are respectively fixedly connected with a frame 322, and the edge of the frame 322 1s higher than that of the first filter membrane 32, the second filter membrane 33 and the third filter membrane 34, so that the microplastics 1s located inside the frame 322, and the microplastics is not scraped off by the top of the placing grooves when the frame 322 1s pulled out, and the frame 322 1s connected with the placing grooves in a sliding way. The outer part of the frame 322 is covered with a sealing ring 323, which ensures that there is no gap between the frame 322 and the placing groove, and prevents leakage. The frame 322 is fixedly provided with a handle 324, which is convenient to push and pull the frame 322, and the microplastics particles on the filter membrane can be collected by pulling out the frame 322.

In a further optimization scheme, the collection assembly 4 includes a collection barrel 41, the top surface of the base 1 is provided with a first installation groove 11, and the collection barrel 41 is placed in the first installation groove 11, so that it not only ensures that the collection barrel 41 will not slide or fall, but also facilitates picking up the collection barrel 41 and pouring the flotation solution in the collection barrel 41 that cannot be reused into the waste recovery device. The collection barrel 41 is communicated with the separation assembly 2 through a return pipe 42, a second water pump 43 is fixedly installed on the return pipe 42, so that the filtered flotation solution can conveniently enter the separation barrel 21 through the return pipe

42 for reuse, the purpose of recycling the flotation solution is achieved, and the waste of the 503220 flotation solution is avoided.

In a further optimization scheme, the digestion assembly 5 comprises a digestion solution storage barrel 51, the top surface of the base 1 is provided with a second installation groove 12, and the digestion solution storage barrel 51 is placed in the second installation groove 12, so as to ensure that not only the digestion solution storage barrel 51 will not slide or dump, but also facilitates picking up the digestion solution storage barrel 51 and pouring the digestion solution in the digestion solution storage barrel 51 that cannot be reused into the waste recycling device.

The digestion solution storage barrel 51 is communicated with the filter assembly 3 through a digestion solution conveying pipe 52, and a third water pump 53 is fixedly installed on the digestion solution conveying pipe 52, so that the digestion solution in the digestion solution storage barrel 51 can be introduced into the filter barrel 31 through the digestion solution conveying pipe 52 for digestion.

The bottom end of the digestion solution conveying pipe 52 is fixedly provided with a microfiltration part, which comprises a shell 521, the top of the shell 521 is fixed and communicated with the bottom end of the digestion solution conveying pipe 52, and an activated carbon adsorption inner core 522 is fixedly installed inside the shell 521. Before entering the digestion solution conveying pipe 52, the digestion solution that has been used once enters the casing 521, passes through the activated carbon adsorption inner core 522 inside the casing 521, and the activated carbon adsorption inner core 522 filters the digestion solution and adsorbs organic substances remaining in the digestion solution, so as to enable the digestion solution to re-enter the filter barrel 31 for secondary digestion operation and improve the utilization rate of the digestion solution.

Step 1: sampling

Collecting soil in the forest;

Step 2: pretreating

Air-drying the soil to remove large particles, plant roots and related impurities in the soil such as such as stones, animal and plant residues, etc., and screening with a 4-8 mesh nylon sieve to obtain a soil sample to be treated;

Step 3: flotation LU503220

Putting the soil sample into the separation barrel 21, adding the flotation solution, then starting the motor 23 to uniformly stir the soil sample and the flotation solution for 15-20min, and then standing until the materials in the separation barrel 21 are divided into an upper non-precipitation layer and a lower precipitation layer, and the non-precipitation layer contains microplastics;

Step 4: filtering

Starting the first water pump 37, discharging the non-precipitation layer in the separation barrel 2 into the filter barrel 31, filtering the non-precipitation layer by the first filter membrane 32, the second filter membrane 33 and the third filter membrane 34, and attaching microplastics with different particle sizes to the first filter membrane 32, the second filter membrane 33 and the third filter membrane 34. After filtering, the non-precipitation layer leaves flotation solution, which flows into the bottom of the separation barrel 21 and is discharged into the collection barrel 41.

In the filtration process, the micro-motor 311 is turned on to make the propeller 312 vibrate the non-precipitation layer in the filter barrel 31, so as to avoid the blockage of the first filter membrane 32, the second filter membrane 33 and the third filter membrane 34, and accelerate the filtration speed.

Step 5: digesting

Adding the digestion solution in the digestion solution storage barrel 51 into the filter barrel 31 through the digestion solution conveying pipe 52, so that the first filter membrane 32, the second filter membrane 33 and the third filter membrane 34 are completely immersed in the digestion solution, and digesting the organic substances remaining in the first filter membrane 32, the second filter membrane 33 and the third filter membrane 34, and then discharging the digestion solution into the digestion solution storage barrel 51; in the digestion process, the micro-motor 311 is turned on, so that the propeller 312 vibrates the digestion solution in the filter barrel 31, and the microplastics is separated from the surfaces of the first filter membrane 32, the second filter membrane 33 and the third filter membrane 34, thus avoiding the accumulation of microplastics, accelerating the digestion speed and improving the digestion effect.

Step 6: collecting. LU503220

Classifying and collecting microplastics with different particle sizes on the first filter membrane 32, the second filter membrane 33 and the third filter membrane 34

In a further optimization scheme, in step 3, when the motor 23 is started, the electric heater 22 is started at the same time to heat the flotation solution to 35-45 degrees, and when the motor stops, the electric heater 22 is turned off.

In a further optimization scheme, in step 3, when the motor 23 is started, the ultrasonic transmitter 27 is started at the same time, and after the motor stops for 5 minutes, the ultrasonic transmitter 27 is turned off.

In a further optimization scheme, in step 5, soaking the digestion solution for 10-15min, replacing it with a new digestion solution, and repeating this step for 2-3 times until the organic substances are digested.

In a further optimization scheme, the flotation solution is vegetable oil, NaCl solution, Nal solution and ZnCl, solution, and the digestion solution is HNO;, KOH, H,O; or the mixed solution of HsOzand H>SO4. In step 5, one of the digestion solutions can be used, or several digestion solutions can be used alternately.

In the description of the present invention, it is to be understood that the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate an orientation or positional relationship based on that shown in the drawings, for convenience of description only, and do not indicate or imply that the indicated devices or elements must have a particular orientation, be constructed and operate in a particular orientation, and are therefore not to be construed as limiting the present invention.

The above-mentioned embodiments are only for describing the preferred embodiments of the present invention and are not intended to limit the scope of the present invention. On the premise of not departing from the design spirit of the present invention, various modifications and improvements made to the technical scheme of the present invention by those of ordinary skill in the art should fall within the protection scope determined by the claims of the present invention.

Claims

CLAIMS LU503220

1. A separation device of microplastics in forest soil, characterized by comprising a base (1), where the base (1) is provided with a separation assembly (2), a filter assembly (3), a collection assembly (4) and a digestion assembly (5), the separation assembly (2) is communicated with the filter assembly (3), the filter assembly (3) is communicated with the collection assembly (4), the collection assembly (4) is communicated with the separation assembly (2), the filter assembly (3) is communicated with the digestion assembly (5), the collection assembly (4) and the digestion assembly (5) are located below the filter assembly (3); a suspension discharge pipe (35) is fixedly installed between the separation assembly (2) and the filtration module (3), and the first water pump (37) is fixedly installed on the suspension discharge pipe (35); one end of the suspension discharge pipe (35) extends through the separation assembly (2) to the inside of the separation assembly (2) and is fixedly connected with a floating ball unit; the other end of the suspension discharge pipe (35) extends through the side wall of the filter barrel (31) to the inside of the separation assembly (2) and is fixedly connected with a shunt unit, where the shunt unit includes an upper shell (356); the top of the upper shell (356) is fixedly connected and communicated with the suspension discharge pipe (35); the upper shell (356) is rotationally connected with the lower shell (358) through the second sealed bearing (357); a propeller (3581) is fixedly installed in the middle of the top surface of the lower shell (358), and a plurality of water diversion holes (3582) are formed in the top surface of the lower shell (358).

2. The separation device of microplastics in forest soil according to claim 1, characterized in that the separation assembly (2) comprises a separation barrel (21), the bottom of the separation barrel (21) is fixedly equipped with an electric heater (22), the bottom of the electric heater (22) is fixedly connected with the base (1), and the top surface of the base (1) is embedded with a motor (23), the output shaft of the motor (23) is fixedly connected with a rotating shaft (24), the rotating shaft (24) sequentially penetrates through the electric heater (22) and the bottom wall of the separation barrel (21) and is fixedly connected with a stirring paddle (25), a first sealed bearing (26) is arranged between the rotating shaft (24) and the bottom wall of the separation barrel (21), and an ultrasonic transmitter (27) is fixedly installed on the outer side wall of the separation barrel (21).

3. The separation device of microplastics in forest soil according to claim 1, characterized in that the filter assembly (3) comprises a filter barrel (31), in which a first filter membrane Gys03220 a second filter membrane (33) and a third filter membrane (34) are detachably installed from top to bottom, and the suspension discharge pipe (35) is located at the top of the first filter membrane (32), the bottom of the filter barrel (31) is fixedly provided with a first drain pipe (36) and a second drain pipe (39), the first drain pipe (36) is communicated with the collection assembly (4), the second drain pipe (39) is communicated with the digestion assembly (5), and the first drain pipe (36) and the second drain pipe (39) are respectively fixedly provided with control valves (38).

4. The separation device of microplastics in forest soil according to claim 3, characterized in that the aperture of the second filter membrane (33) is smaller than that of the first filter membrane (32) and larger than that of the third filter membrane (34).

5. The separation device of microplastics in forest soil according to claim 1, characterized in that the collection assembly (4) comprises a collection barrel (41), the top surface of the base (1) is provided with a first installation groove (11), the collection barrel (41) is placed in the first installation groove (11), and the collection barrel (41) is communicated with the separation assembly (2) through a return pipe (42), and a second water pump (43) is fixedly installed on the return pipe (42).

6. The separation device of microplastics in forest soil according to claim 1, characterized in that the digestion assembly (5) comprises a digestion solution storage barrel (51), the top surface of the base (1) is provided with a second installation groove (12), the digestion solution storage barrel (51) is placed in the second installation groove (12), and the digestion solution storage barrel (51) is communicated with the filter assembly (3) through a digestion solution conveying pipe (52), and a third water pump (53) is fixedly installed on the digestion solution conveying pipe (52).

7. A separation method of microplastics in forest soil, which is applied to the separation device of microplastics in forest soil according to any one of claims 1 - 6, characterized by comprising the following specific steps: step 1: sampling collecting soil in the forest; step 2: pretreating air-drying the soil to remove gravel, plant roots and other related impurities in the soil 191503220 obtain a soil sample to be treated; step 3: flotation putting the soil sample into a separation assembly (2), adding flotation solution, stirring, and standing until the materials in the separation assembly (2) are divided into an upper non-precipitation layer and a lower precipitation layer, where the non-precipitation layer contains microplastics; step 4: filtering starting the first water pump (37), discharging the non-precipitation layer in the separation assembly (2) into the filter assembly (3), filtering the non-precipitation layer by the filter assembly (3), attaching microplastics to the filter assembly (3), and leaving flotation solution after filtering the non-precipitation layer, flowing the flotation solution into the bottom of the separation assembly (3), and discharging the flotation solution into the collection assembly (4); step 5: digesting adding the digestion solution in the digestion assembly (5) into the filter assembly (3), digesting the organic substances remaining in the filter assembly (3), and then discharging the digestion solution into the digestion assembly (5); step 6: collecting classifying and collecting microplastics with different particle sizes in the filter assembly

(3).

8. The separation method of microplastics in forest soil, according to claim 7, characterized in that in step 3, the electric heater (22) is started to heat the flotation solution to 35-45 degrees.

9. The separation method of microplastics in forest soil according to claim 7, characterized in that in step 3, the ultrasonic transmitter (27) 1s started.

10. The separation method of microplastics in forest soil according to claim 7, characterized in that in step 5, soaking the digestion solution for 10-5min, replacing it with a new digestion solution, and repeating this step for 2-3 times until the organic substances are digested.