Automatic integrated device for separating soil and sediment micro-plastics and separation method

Abstract

According to the soil and sediment micro-plastic separation automatic integrated device and the separation method, the flotation cylinder, the digestion cylinder, the suction filtration device, the waste liquid collection pipe and other components are integrated, and automatic and efficient separation and extraction of micro-plastics in soil and sediment are achieved. The device realizes rapid and efficient separation and extraction of micro-plastics in soil and sediments, and has the advantages of no need of manual intervention in the separation process, high automation degree, less external environment interference, high micro-plastic extraction and separation efficiency and the like.

Description

Technical Field

[0001] The present invention relates to the field of soil detection technology, and specifically to an automatic integrated device and method for separating microplastics from soil and sediment. Background Art

[0002] Microplastics refer to plastic particles with a diameter of less than 5 mm, which are a major carrier of pollution. Microplastics are dispersed in large quantities and attached to water, soil and other environments in the environment, and then enter the food chain, causing great health damage to animals and humans. In recent years, it has become a key research direction in the environmental science community.

[0003] Before studying microplastics in soil and sediments, the microplastic particles in the soil and sediments need to be extracted and separated to remove the interference of other impurities on the experimental process in subsequent experiments. Usually, after the experimenters obtain soil or sediment samples, they are bagged and sealed, and then taken back to the laboratory for processing. The microplastic particles in the soil and sediments are separated and digested through processes such as flotation and digestion. After filtering, dry microplastic particles are obtained on the filter disc for further analysis.

[0004] The existing separation process needs to be completed in the laboratory. There is a lot of preparation work before the experiment, including preparing multiple beakers, connecting pipes, preparing flotation liquid and digestion liquid, etc. During the experiment, it is also necessary to manually stir the materials and continuously add flotation liquid and digestion liquid, which is extremely inconvenient. Soil and sediment samples are often large in number. Throughout the project, the experimenters have to repeat the separation operation dozens of times, which consumes a lot of manpower and time.

[0005] Although there are many records of equipment and methods for the separation and extraction of microplastics in existing literature, their use environment is basically inseparable from the indoor laboratory environment. There is no real automated equipment that can be used anytime and anywhere, or even directly perform separation operations outdoors. Summary of the invention

[0006] The present invention provides an automatic integrated device and method for separating microplastics from soil and sediments, which can achieve rapid and efficient separation and extraction of microplastics in soil and sediments, and has the advantages of no need for human intervention in the separation process, high degree of automation, little interference from the external environment, and high efficiency in microplastic extraction and separation.

[0007] To achieve the above object, the technical solution of the present invention is as follows: An automatic integrated device for separating microplastics from soil and sediments, wherein a flotation liquid storage tank is installed in the inner cavity of the machine body, a flotation liquid outlet pipe is arranged in the flotation liquid storage tank and connected to the flotation cylinder, an overflow channel is arranged at the upper end of the flotation cylinder and connected to the digestion cylinder, a digestion liquid storage tank is arranged next to the digestion cylinder, a digestion liquid outlet pipe is arranged in the digestion liquid storage tank and connected to the digestion cylinder, one end of a suction pipe is connected to the digestion cylinder, the other end of the suction pipe is connected to the funnel on the upper part of the suction device, the bottom of the funnel is a glass filter membrane, below the glass filter membrane is a suction tank, and the suction tank is connected to the vacuum pump through an air pipe; the upper end face of the machine body is hingedly connected to the machine cover.

[0008] The flotation liquid is saturated NaCl or NaBr. Saturated NaCl or NaBr solution has a large density, and the density of most microplastics is less than that of the solution, so they will float in the upper clear liquid of the flotation liquid to complete the separation. The digestion reaction can digest the organic matter in the water through oxidation reaction, eliminate the influence of organic impurities on subsequent experiments, and play a certain role in sterilization and disinfection; the digestion liquid is 30% H2O2 by mass. H2O2 has strong oxidizing properties and can react and digest with organic impurities in the water body, thereby removing organic impurities attached to microplastics and increasing the purity of the obtained microplastics; the digestion liquid reacts with organic matter, and the resulting flocculated precipitate remains in the lower layer of the digestion cylinder, and the upper clear liquid enters the filtration device through the suction pipe. Under the action of the vacuum pump, the suction storage tank of the filtration device forms a negative pressure environment, and the liquid at the suction funnel is accelerated to pass through the glass filter membrane, thereby achieving the effect of quickly extracting microplastics in the liquid; The bottom of the flotation cylinder is installed in the cylinder seat, a number of ultrasonic vibrators A are installed on the side wall of the cylinder seat, and a heater A is installed at the bottom of the cylinder seat; the ultrasonic frequency is 40kHz. The ultrasonic instrument ultrasonically vibrates the soil and sediment in the flotation cylinder, so that the attached microplastics can be quickly separated and floated to the upper flotation liquid; the water temperature of the flotation cylinder is maintained at 50±5℃, which is conducive to the dispersion of soil and sediment particles and improves the flotation effect.

[0009] The bottom of the digestion cylinder is installed in the cylinder seat, a number of ultrasonic vibrators B are installed on the side wall of the cylinder seat, and a heater B is installed at the bottom of the cylinder seat. The ultrasonic instrument digests the solution in the cylinder through ultrasonic oscillation, so that the oxidant can react quickly with the organic matter to accelerate the reaction process; the liquid temperature in the digestion cylinder is maintained at 50±5℃, which also increases the reaction rate of the digestion solution and impurities.

[0010] The bottom of the suction filtration tank is connected to the waste liquid storage tank through a pipeline, and a one-way valve and a liquid pump are arranged on the pipeline. The one-way valve can be used to pump the waste liquid into the waste liquid storage tank for collection, so as to prevent the waste liquid from being discharged at will and polluting the environment.

[0011] A waste liquid outlet pipe is arranged at the bottom of the waste liquid storage tank, and an electric switch valve and a liquid pump are arranged on the waste liquid outlet pipe. When the waste liquid storage tank is full, a discharge hose can be connected, and the switch valve can be opened through the control panel to discharge the waste liquid in the storage tank to a designated pool for treatment.

[0012] One end of the flotation liquid outlet pipe extends into the bottom of the inner cavity of the flotation liquid storage tank to connect to the liquid pump, and the middle part of the straight section of the flotation liquid outlet pipe is connected through a rotating joint, and the rotating joint is fixed on the inner wall of the liquid storage tank; the rotating joint can realize the deflection of the flotation liquid outlet pipe without hindering the upward removal and replacement of the flotation tube.

[0013] One end of the digestion liquid outlet pipe extends into the bottom of the inner cavity of the digestion liquid storage tank to connect the liquid pump, and the middle of the straight section of the digestion liquid outlet pipe is connected through a rotating joint, and the rotating joint is fixed on the inner wall of the digestion liquid storage tank. The rotating joint can realize the deflection of the digestion liquid outlet pipe, and does not hinder the upward removal and replacement of the digestion cylinder.

[0014] A filtrate pump is fixedly arranged on the inner wall side of the funnel and connected to the filtration suction pipe. The filtrate pump extracts the upper clear liquid in the digestion cylinder into the filtration funnel.

[0015] Three liquid level sensors are arranged on the inner wall of the digestion cylinder, and the liquid level sensors are connected with the filtrate pump signal.

[0016] A liquid level sensor is arranged at the low liquid level of the inner cavity of the funnel, and the liquid level sensor is connected with the vacuum pump signal.

[0017] A liquid level sensor is arranged at the low liquid level of the inner cavity of the waste liquid storage tank, and the liquid level sensor is connected with the liquid pump signal of the waste liquid outlet pipe.

[0018] A spare flotation cylinder and a spare digestion cylinder are also placed in the inner cavity of the machine body.

[0019] The operating steps of the equipment for microplastic separation are: Place soil and sediment samples into the flotation liquid storage tank, install a glass filter membrane in the filtration device, select the flotation time and digestion time on the control panel, and close the cover; (2) The flotation liquid storage tank adds the flotation liquid into the flotation cylinder through the liquid pump and the flotation liquid outlet pipe until it reaches the position of the liquid level sensor, then stops adding liquid, and the heater and ultrasonic vibrator at the bottom of the flotation cylinder start working for a specified time; (3) After the flotation process is completed, the flotation liquid storage tank continues to add flotation liquid to the flotation cylinder, and after reaching the overflow port, it flows into the digestion cylinder. When the flotation liquid carrying microplastic particles is injected into the digestion cylinder and reaches the position of the first liquid level sensor, the flotation liquid storage tank stops adding liquid to the flotation cylinder, and the digestion liquid storage tank starts to inject digestion liquid into the digestion cylinder through the digestion liquid outlet pipe. When the level of the injected digestion liquid reaches the position of the third liquid level sensor, the heater and ultrasonic vibrator at the bottom of the digestion cylinder start to work for a specified time; (4) After the digestion process is completed, the liquid pump of the suction funnel starts to extract liquid from the digestion cylinder through the suction pipette. At the same time, the liquid level sensor in the suction funnel senses that liquid has been injected, the vacuum pump starts to work, and the filtration begins. When the liquid level in the digestion cylinder drops to the position of the second liquid level sensor, the liquid pump of the suction funnel stops working. (5) When the liquid level is lower than the position of the liquid level sensor of the filtration funnel, the vacuum pump stops working after a delay of 30 seconds; during the filtration process, the liquid level sensor installed at the bottom of the filtration tank senses the liquid level, and the discharge pump starts working to discharge the waste liquid into the waste liquid storage tank for storage; (6) After the equipment stops running, open the cover and take out the glass filter membrane to obtain the collected microplastics; manually push the flotation liquid outlet tube and the digestion liquid outlet tube aside, then take out the flotation cylinder and the digestion cylinder, and put in a spare clean flotation cylinder and digestion cylinder to separate and extract the next group of microplastics. The staff can clean and wash the used flotation cylinder and digestion cylinder for secondary use. Advantages of the invention

[0020] The present invention changes the existing separation and extraction methods and required environment for soil and sediment microplastics. With this integrated and automated equipment placed on a tool cart, microplastic separation and extraction can be performed anytime and anywhere without the restriction of a laboratory environment, and is suitable for various microplastic extraction occasions.

[0021] The device of the present invention has the characteristics of high automation. All liquids are completely connected through pipelines and liquid pumps during the transportation process. The start and stop of the liquid pump and the vacuum pump are automatically controlled by the liquid level sensor. The process does not require manual participation. It only needs to load the dried soil and sediment into the flotation cylinder at the beginning, add the flotation liquid and digestion liquid at regular intervals, and discharge the waste liquid at regular intervals.

[0022] 3. The operation process of the present invention is enclosed by the body and the cover, so the equipment can achieve completely sealed operation. Impurities in the environment cannot enter the interior of the equipment to have an adverse effect on the results of extraction and separation, and the separated and extracted microplastic impurities are less.

[0023] 4. The present invention adopts suction filtration separation, heating + ultrasonic flotation and digestion, and the process is efficient and fast. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the vertical structure of the device of the present invention; Figure 2 It is a schematic diagram of the top view of the structure of the device of the present invention; Figure 3 It is a schematic diagram of the pipeline directions of each component of the equipment; Figure 4 It is a schematic diagram of the cross-sectional structure of a flotation liquid storage tank or a digestion liquid storage tank; The serial numbers and component names in the figure are: 1-machine body; 11-machine cover; 2-flotation liquid storage tank; 21-flotation liquid outlet pipe; 3-flotation cylinder; 31-heater A; 32-ultrasonic vibrator A; 4-digestion cylinder; 41-heater B; 42-ultrasonic vibrator B; 5-digestion liquid storage tank; 51-digestion liquid outlet pipe; 6-filtration device; 61-filtration straw; 62-vacuum pump; 63-funnel; 64-filtration tank; 65-glass filter membrane; 71-spare flotation cylinder; 72-spare digestion cylinder; 8-waste liquid storage tank; 81-waste liquid outlet pipe. DETAILED DESCRIPTION Example 1

[0025] An automatic integrated device for separating microplastics from soil and sediments, wherein a flotation liquid storage tank 2 is installed in the inner cavity of a machine body 1, a flotation liquid outlet pipe 21 is arranged in the flotation liquid storage tank 2 to pass into a flotation cylinder 3, an overflow channel is arranged at the upper end of the flotation cylinder 3 to pass into a digestion cylinder 4, a digestion liquid storage tank 5 is arranged next to the digestion cylinder 4, a digestion liquid storage tank 5 is arranged in the digestion liquid storage tank 5 to pass into the digestion cylinder 4, one end of a suction filtration pipe 61 is connected to the digestion cylinder 4, the other end of the suction filtration pipe 61 is connected to a funnel 63 at the upper part of a suction filtration device 6, a glass filter membrane 65 is provided at the bottom of the funnel 63, a suction filtration tank 64 is provided below the glass filter membrane 65, and the suction filtration tank 64 is connected to a vacuum pump 62 through an air pipe; the upper end surface of the machine body 1 is hingedly connected to a machine cover 11.

[0026] The bottom of the flotation cylinder 3 is installed in the cylinder seat, a number of ultrasonic vibrators A32 are installed on the side wall of the cylinder seat, and a heater A31 is installed at the bottom of the cylinder seat; The bottom of the digestion cylinder 4 is installed in the cylinder seat, a number of ultrasonic vibrators B42 are installed on the side wall of the cylinder seat, and a heater B41 is installed at the bottom of the cylinder seat.

[0027] The bottom of the suction filtration tank 64 is connected to the waste liquid storage tank 8 through a pipeline, and a one-way valve and a liquid pump are arranged on the pipeline; a waste liquid outlet pipe 81 is arranged at the bottom of the waste liquid storage tank 8, and an electric switch valve and a liquid pump are arranged on the waste liquid outlet pipe 81.

[0028] One end of the flotation liquid outlet pipe 21 extends into the bottom of the inner cavity of the flotation liquid storage tank 2 to connect to the liquid pump, and the middle of the straight section of the flotation liquid outlet pipe 21 is connected through a rotary joint, and the rotary joint is fixed on the inner wall of the liquid storage tank 2; One end of the digestion liquid outlet pipe 51 extends into the bottom of the inner cavity of the digestion liquid storage tank 5 to connect to the liquid pump. The middle of the straight section of the digestion liquid outlet pipe 51 is connected through a rotary joint, and the rotary joint is fixed on the inner wall of the digestion liquid storage tank 5.

[0029] A filtrate pump is fixedly arranged on the inner wall side of the funnel 63 and connected to the filtration suction pipe 61 .

[0030] The inner wall of the digestion cylinder 4 is provided with a high and low liquid level sensor, and the liquid level sensor is connected to the filtrate pump signal; the liquid level sensor is also connected to the liquid pump signal of the digestion liquid outlet pipe 51.

[0031] A liquid level sensor is provided at the low liquid level of the inner cavity of the funnel 63 , and the liquid level sensor is connected to the vacuum pump 62 by signal.

[0032] A liquid level sensor is arranged at the low liquid level of the inner cavity of the waste liquid storage tank 8 , and the liquid level sensor is connected to the liquid pump signal of the waste liquid outlet pipe 81 .

[0033] A liquid level sensor is arranged at the high liquid level of the inner cavity of the flotation cylinder 3 , and the liquid level sensor is connected to the liquid pump signal of the flotation liquid outlet pipe 21 .

[0034] The inner cavity of the machine body 1 also contains a spare flotation cylinder 71 and a spare digestion cylinder 72 .

Claims

1. Automatic integrated device for separation of soil and sediment microplastics, characterized by: A flotation liquid storage tank (2) is installed in the inner cavity of the machine body (1). A flotation liquid outlet pipe (21) is arranged in the flotation liquid storage tank (2) and is connected to the flotation cylinder (3). An overflow channel is arranged at the upper end of the flotation cylinder (3) and is connected to the digestion cylinder (4). A digestion liquid storage tank (5) is arranged next to the digestion cylinder (4). A digestion liquid outlet pipe (51) is arranged in the digestion liquid storage tank (5) and is connected to the digestion cylinder (4). One end of a suction filter pipe (61) is connected to the digestion cylinder (4). The other end of the suction filter pipe (61) is connected to a funnel (63) at the upper part of the suction filter device (6). A glass filter membrane (65) is provided at the bottom of the funnel (63). A suction filter tank (64) is provided below the glass filter membrane (65). The suction filter tank (64) is connected to a vacuum pump (62) through an air pipe. The upper end surface of the machine body (1) is hingedly connected to a machine cover (11).

2. The automatic integrated device for separating microplastics from soil and sediment according to claim 1, characterized in that: The bottom of the flotation cylinder (3) is installed in a cylinder seat, a plurality of ultrasonic vibrators A (32) are installed on the side wall of the cylinder seat, and a heater A (31) is installed on the bottom of the cylinder seat; The bottom of the digestion cylinder (4) is installed in a cylinder seat, a plurality of ultrasonic vibrators B (42) are installed on the side wall of the cylinder seat, and a heater B (41) is installed on the bottom of the cylinder seat.

3. The automatic integrated device for separating microplastics from soil and sediment according to claim 1, characterized in that: The bottom of the suction filtration tank (64) is connected to the waste liquid storage tank (8) via a pipeline, and a one-way valve and a liquid pump are arranged on the pipeline; a waste liquid outlet pipe (81) is arranged at the bottom of the waste liquid storage tank (8), and an electric switch valve and a liquid pump are arranged on the waste liquid outlet pipe (81).

4. The automatic integrated device for separating microplastics from soil and sediment according to claim 1, characterized in that: One end of the flotation liquid outlet pipe (21) extends into the bottom of the inner cavity of the flotation liquid storage tank (2) to connect to the liquid pump, and the middle of the straight section of the flotation liquid outlet pipe (21) is connected via a rotary joint, and the rotary joint is fixed to the inner wall of the liquid storage tank (2); One end of the digestion liquid outlet pipe (51) extends into the bottom of the inner cavity of the digestion liquid storage tank (5) to connect to the liquid pump, and the middle part of the straight section of the digestion liquid outlet pipe (51) is connected via a rotary joint, and the rotary joint is fixed to the inner wall of the digestion liquid storage tank (5).

5. The automatic integrated device for separating microplastics from soil and sediment according to claim 1, characterized in that: A filtrate pump is fixedly arranged on the inner wall side of the funnel (63) and is connected to the filtrate suction pipe (61).

6. The automatic integrated device for separating microplastics from soil and sediment according to claim 8, characterized in that: The inner wall of the digestion cylinder (4) is provided with a high and low liquid level sensor, and the liquid level sensor is connected to the filtrate pump signal; the liquid level sensor is also connected to the liquid pump signal of the digestion liquid outlet pipe (51).

7. The automatic integrated device for separating microplastics from soil and sediment according to claim 8, characterized in that: A liquid level sensor is provided at a low liquid level in the inner cavity of the funnel (63), and the liquid level sensor is connected to the vacuum pump (62) via a signal.

8. The automatic integrated device for separating microplastics from soil and sediment according to claim 8, characterized in that: A liquid level sensor is provided at a low liquid level in the inner cavity of the waste liquid storage tank (8), and the liquid level sensor is connected to the liquid pump signal of the waste liquid outlet pipe (81).

9. The automatic integrated device for separating microplastics from soil and sediment according to claim 1, characterized in that: A liquid level sensor is provided at a high liquid level in the inner cavity of the flotation cylinder (3), and the liquid level sensor is connected to a liquid pump signal of the flotation liquid outlet pipe (21).

10. The automatic integrated device for separating microplastics from soil and sediment according to claim 1, characterized in that: A spare flotation cylinder (71) and a spare digestion cylinder (72) are also placed in the inner cavity of the machine body (1).

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